Role of Lactobacilli in Gastrointestinal · PDF fileRole of Lactobacilli in Gastrointestinal Ecosystem ... biotic and abiotic components of the GIT ... Role of Lactobacilli in Gastrointestinal

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Bulgarian Journal of Agricultural Science, 12 (2006), 63-114National Centre for Agrarian Sciences

Role of Lactobacilli in Gastrointestinal EcosystemS. A. DENEVTrakia University Department of Biology, Section of Microbiology, AgriculturalFaculty, BG – 6000 Stara Zagora, Bulgaria

Abstract

DENEV, S. A., 2006. Role of Lactobacilli in gastrointestinal ecosystem. Bulg. J. Agric.Sci., 12: 63-114

Lactobacilli are normal and important inhabitants of the gastrointestinal tract of human andanimals. They constitute an integral part of healthy gastrointestinal microecology and havereceived considerable scientific attention. The role that lactobacilli play in the ecology of thegastrointestinal tracts of humans and animals may be of major importance, but it is as yet poorlyunderstood.

The present review summarizes the current state of knowledge regarding the role of lactoba-cilli in gastrointestinal ecosystem. Topics covered include: nutritional and therapeutic benefitsof lactobacilli; deconjugation of bile acids; neutralization of toxins and other intestinal reac-tions; protection against intestinal pathogens by production of antibacterial substances suchas organic acids, hydrogen peroxide, bacteriocins and etc.; stabilization of intestinal microflora,excluding colonization of enteropathogenic bacteria by adhesion to the intestinal wall and com-petition for nutrients; reduction of the cholesterol level in blood serum by cholesterol assimila-tion; decrease risk of colon cancer by detoxification of toxic, mutagenic and carcinogenic sub-stances, and modulation of fecal procarcinogenic enzymes such as b-Glucuronidase, azoreductaseand nitroreductase; tumor suppression by stimulation of non-specific and specific immuneresponse.Key words: Lactobacilli, gastrointestinal microflora, gastrointestinal ecosystem, antago-nistic, antimutagenic, anticarcinigenic, immunological effectsAbbreviations: GIT - Gastrointestinal tract; GIE - Gastrointestinal ecosystem; GIM- Gastrointestinal microflora; CE - Competitive exclusion; IT – Intestinal tract; LAB- Lactic acid bacteria; BSH - Bile salt hydrolase

Introduction

Gastrointestinal ecosystems (GE) ofhumans and animals are complex, open,integrated, interactive units containing

many microbial species, which are dividedin two major groups: autochthonous (in-digenous) which exist in close associationwith the gut epithelium and allochthonous(non-indigenous) which occurs free in the

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gut lumen. It is, however, difficult to makea clear distinction between the two groups.In regard to autochthonous microorgan-isms, Savage (1977, 2001) has suggesteda useful definition. According to Savagethe autochthonous microflora must:

• Be capable of growing anaerobically;• Be always present in the gut of normal adult

animals;• Colonize the various parts of the digestive

tract;• Establish their own habitats during succes-

sion (i.e., sequential establishment of the variousmicroorganisms) in infant animals;

• Maintain a stable population in normal adults;

Associate intimately with the epithelialmucosa of the tract of the gut they colo-nize.

Its high population density, wide diver-sity, and complexity of interactions char-acterize the microbial community inhabit-ing the gastrointestinal tract (GIT). It hasbeen estimated that there are in the gut1014 bacterial cells whereas the numberof eukaryotic cells comprising the humanbody amounts to only 1013 (Luckey, 1972).Within this population there are about 500different bacterial species (Savage, 1984;Ewing and Cole, 1994; Bengmark, 1998;Bird et al., 2000; Miguel, 2001; Cole et al.2003), although 40 types comprise 99%of the microflora (Tannock, 1988). Thehuman body contains 10 times more pro-tective indigenous flora than do eukary-otic cells (Tancrede, 1992). The uniquebiotic and abiotic components of the GIT(specialized chemical environment and ap-propriately adapted microbes) permit thedefinition of the “gastrointestinal ecosys-tem” (GIE) (Savage, 1977, 2001). Thesystems are established during postnatallife, when various microbial species findtheir way into the intestinal tract. When

germfree animals are conventionalized, i.e.colonized with conventional flora, similarecosystems are established. Results ofstudies on ex-germfree animals have dem-onstrated that some microbial species mayact synergistically and others may act an-tagonistically with each other. The exactmechanisms involved in these interactions,however, have not been elucidated(Ducluzeau et al., 1984; Midtvedt et al.,1987; Savage, 2001).

The numerically dominant inhabitantsof the GIE are obligate anaerobes. In theneonatal mammal, such as the human in-fant, piglet and calf the intestinal tract issterile at birth (Haenel, 1970). It is rapidlycolonized from the mouth and rectum, usu-ally initially with the mother’s vaginal andperianal flora. In detailed of wide varietyof young animals showed that at birth theGIT becomes flooded with multiplyingbacteria: coliforms, bifidobacteria, strep-tococci, including enterococci, clostridia,bacteroides, and other anaerobes, followedrapidly by lactobacilli.

The metabolic activities of the gas-trointestinal microflora (GIM) are ex-tremely complex and diverse. Many inves-tigations have shown that intestinal bacte-ria play a major part in the enzyme activi-ties of intestine; production of b-glucu-ronidase (Hawksworth et al., 1971),azoreductase (Brown, 1981; Raffii et al.,1990), nitroreductase (Zachariah andJuchau, 1974), 7a-dehydroxylase (Hiranoet al., 1981), 7a-dehydrogenase (Wilkinsand Tassell, 1983), toxic, carcinogenic ormutagenic metabolites from diet (Rowlandet al., 1985; Goldin et al., 1996);deconjugation of bile acids (Aries and Hill,1970; Floch et al., 1971, 1972; Gilliland andSpeck, 1977a; Tannock et al.,1994); detoxi-fication of dietary toxicants; enterohepaticcirculation of drugs, food additives and ste-

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roids; alteration in susceptibility of hosttumor induction etc. For review see Drasarand Hill (1974), Yuguchi et al., (1992),Denev (1996, 1997); Bird et al. (2000);Denev et al. (2000); Savage (2001).

The composition and metabolic activi-ties of GIM is very complex and strictlydetermined by the local environmentalconditions (Croucher et al., 1983; Edwardset al., 1985; Seddon, 1989), physiologicalinteractions (Floch et al., 1971, 1972), diet(Winitz et al., 1970; Maier et al., 1974;Moore and Holdeman, 1975, Denev,1993a; Savage, 2001) and another factors(Hill et al., 1982; Kim, 1989; Seddon, 1989;Mitsuoka, 1990, Denev, 1996, 1997). Thesize of the microbial population in differ-ent regions of the tract also varies betweenanimal species too (Savage, 1977;Tannock, 1984, 2004).

Microbiological interest in the role oflactobacilli inhabiting the GIT dates, fromthe time of Metchnikoff (1903, 1907) whenit was observed that the natural fermen-tation of milk by lactic acid bacteria (LAB)prevented the growth of non-acid-toleranttypes of microbe. It was proposed that, iflactic fermentation prevented the putre-faction of milk, it should have a similareffect in the digestive tract. The implan-tation of lactobacilli in the GIT would sup-press the growth of “putrefactive” bacte-ria, thus reducing the amount of toxic sub-stances generated in the digestive tract.Although Metchnikoff’s hypothesis waspopular at the beginning of that century itwas unsupported by experimental or clini-cal proof, partly due to the lack of adequateexperimental techniques at that time. How-ever, the remarkable developments in tech-niques for microbiological research and forraising germ-free animals in recent years,have produced data showing the impor-tant role played by intestinal bacteria in

animals, leading to a fresh reassessmentof Metchnikoff’s hypothesis.

The balance of the GIM is then con-trolled by acid secretion in the stomach (al-though this is buffered to some extent bythe milk imbibed) and ingestion of immu-noglobulins and other protective factors inthe mother’s milk, so that lactobacilli be-come the dominant organisms and othergroups rapidly decline (Reiter, 1978). Lac-tobacilli predominate in the stomach andsmall intestine, but in the jejunum and largeintestine strict anaerobes such as bacteroi-des are the majority flora and lactobacilliconstitute only 0.07-1.0% of the total flora.This desirable predominance of lactoba-cilli in the upper intestine, which is estab-lished on suckling, help to prevent the po-tentially lethal diarrhea or scouring that oc-curs in young animals when enteropatho-genic coliforms proliferate in the upperGIT. The mechanisms by which lactoba-cilli suppress the rest of the bacterial florais not fully understood but is probably partlydue to lactic acid production and partly toinhibitory systems present in the raw milk,including the lactoperoxidase system,which can be activated by H2O2 -produc-ing lactobacilli (Reiter, 1978). In the younganimals, lactobacilli usually become theprincipal component of stomach and smallintestine, developing from about 104 to108/g intestinal content, highest numbersbeing obtained in the lower part of thesmall intestine (Smith, 1971).

Lactobacillus spp. are important in cre-ating a balanced microbial population inGIE (Sandine et al., 1972; Shahani andAyebo, 1980; Bianchi-Salvadory, 1986;Denev et al., 2000; Varnam, 2002;Tannock, 2004). The interest in their ex-istence in different areas of the body andtheir role in the host and microflora-relatedphysiochemical conditions in the organism

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has become one of the subjects of a com-paratively new research field - microbialecology (Haenel et al., 1957, 1957a,Haenel, 1980; Dubos, 1966; Reuter, 1975;Goldin and Gorbach, 1984; Gorbach, 1990;Prins, 1996; Mackie et al., 1999).

The therapeutic and nutritive attributesof LAB particularly the lactobacilli havebeen actively researched since then(Speck, 1976; Sandine et al., 1972;Sandine, 1979; Shahani and Ayebo, 1980;Garg and Mital, 1992). Thereafter, manyinvestigations have shown that the pres-ence of lactobacilli in the intestinal tract(IT) is helpful in maintaining good health,restoring body vigor, stimulating host im-mune mechanisms, productivity, and com-bating intestinal and other disease disor-ders (Rettger et al., 1935; Gilliland andSpeck, 1977; Gilliland, 1979; Friend andShahani, 1984; Perdigon et al., 1987;Denev, 1993; Denev et al., 2000;Morishita, 2003; Sandholm and M.Saarela, 2003).

Subsequent research has emphasizedthat the lactobacilli to be used as dietaryadjunct must be able to survive the hostileenvironment in the GIT and proliferate(Hawley et al., 1959; Gilliland et al., 1978;Hargrove and Alford, 1978). Several in-vestigations have shown that Lactobacil-lus acidophilus is not only capable of es-tablishing in the complex ecosystem of thegut (Kopeloff, 1926; Myers, 1931; Starket al., 1934; Rettger et al., 1935) but alsoof imparting many health benefits(Gilliland, 1989; Mital and Garg, 1992;Sellars, 1992; Mital et al., 1995). Theseinclude stabilization of intestinal microflora,antagonistic action toward intestinal andfood-borne pathogens, control of serumcholesterol, prevention of colon cancer,and enhanced availability of nutrients(Shah, 2001).

There are many other reports, begin-ning with Metchnikoff suggesting thatLAB particularly the lactobacilli are a nu-merically dominant and important group ofmicroorganisms colonizing the GIT and ofthe female reproductive tract of humans(Drasar and Hill, 1974; Mitsuoka et al.,1975; Conway, 1989; Mikelsaar andMandar, 1993; Varnam, 2002) and animals(Roach et al., 1977; Savage, 1975, 1977;Sharpe, 1981; Worthington and Fulghum,1988; Tannock et al., 1990; Denev et al.2000; Tannock, 1992, 2004).

Beyond these roles, some Lactobacil-lus species have been exploited as “livemicrobial supplements”, intended to ben-eficially affect the host by balancing thenatural microflora of the GIT. Probiotics,literally meaning “for life” (Fuller, 1992)have been the subject of considerable sci-entific and commercial attention over thepast two decades (for review see Denev,1996; 1997; Fuller, 1989, 1997;Klaenhammer, 1995, 1997, 1997a,b; Denevet al., 2000; Shah, 2001; Tannock, 2002,2004).

Due to their many beneficial proper-ties lactobacilli have attracted the great-est attention of researchers. In addition,the mechanisms involved in the expressionof these activities are not clearly under-stood. Therefore, an attempt has beenmade to review the pertinent literature onthese aspects critically.

MAJOR CHARACTERISTICS OF THELACTOBACILLI

Lactobacilli are members of the LAB,a broadly defined group characterized bythe formation of lactic acid as a sole ormain end product of carbohydrate metabo-lism (Tannock, 2004). There are 44 spe-cies of lactobacilli listed in Bergey’sManual of Systematic Bacteriology

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(Kandler and Weiss, 1986). Eighty spe-cies of lactobacilli are recognized at present(Satokari et al., 2003). Many Lactobacil-lus spp. have been detected in GT of ver-tebrate animals and humans (Table 1.).

Members of the genus Lactobacillusconstitute an extremely diverse group ofbacteria that provide considerable benefitsto humans and animals as natural inhabit-ants of the IT. They are Gram-positive,non-sporeforming, rods or coccobacilliwith a G+C content usually below 50mol%. The mol % G+C of the DNAranges from 32-53. They are strictly fer-mentative, aerotolerant (microaerophilic)or anaerobic and have complex nutritionalrequirements (carbohydrates, amino acids,peptides, fatty acid esters, salts, nucleicacid derivatives, vitamins). Various com-pounds (e.g. citrate, malate, tartarate,quinolate, nitrate, nitrite, etc.) may be me-tabolized and used as energy source(Kandler and Weiss, 1986; Hammes andVogel, 1995). Using glucose as a carbonsource, lactobacilli may be either homo-fermentative (producing more than 85%of fermentative products as lactic acid) orheterofermentative (producing lactic acid,carbon dioxide, ethanol, and/or acetic acidin equimolar amounts). The nutritional re-quirements of lactobacilli are reflected intheir habitats, which are rich in carbohy-drate-containing substrates: they are foundon plants or material of plant origin, in fer-mented or spoiled food, or in associationwith the bodies of animals. Lactobacilli arecatalase and cytochrome negative, usuallynon-motile, that does not usually reducenitrate. Gelatin not liquefied. Casein notdigested but small amounts of soluble ni-trogen produced by most strains. Indoleand H2S2 not produced. Lactobacilli areaciduric with optimal pH 5.5-6.2. Growthtemperature range of Lactobacilli are 2-

53oC - optimum generally 30-40oC(Hammes and Vogel, 1995). The classifi-cation of lactobacilli relies on biochemi-cal-physiological criteria include threegroups (Table 2).

Recently, Hammes et al. (1991), Potet al. (1994), Gasson and Vos (1994),Klaenhammer (1995), Hammes and Vogel(1995), Denev et al.(2000), Tannock(2002) reviewed lactobacilli. Venema etal. (1996) in the former publications athorough survey of the ecophysiology,genetics, metabolism, biotechnology andapplication of the organisms was pre-sented. For the role of lactobacilli in healthand disease Wood (1992) and Denev etal. (2000) provide an excellent survey. Formicroecology of lactobacilli inhabiting theGIT see Ahrne et al. (1998), Tannock(1988a, 1990, 1995, 2002).

COLONIZATION OF LACTOBACILLI TOEPITHELIAL SURFACES

In recent years much attention hasbeen given to the study of the administra-tion of living microbial preparations to farmanimals (probiotics), which would to as-sure improvement in nutrition and in theanimal’-s resistance to disease. Since thereport of Metchnikoff (1907) many reportshave indicated that Lactobacillus strainsare important in creating balanced micro-bial populations in the IT. Colonization ofintestinal tissue by lactobacilli is a naturalphenomenon which arises earlier and moreintensely in animals reared on traditionalfarms than those in factory-farms, wherecolonization may be detained or upset byacceleration of the rearing cycles, andabove all by the often indiscriminate useof antibiotics at subtherapeutic levels.

For the administration of Lactobacil-lus culture to animals to be of practical

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Table 1Gastrointestinal Species of Lactobacilli

Species References

L. acidophilus Axelsson and Lindgren (1987); Tannock et al. (1990); Arihara et al.(1996); Holzapfel et al. (2001)

L. agilis Baele et al. (2001)L. animalis Roach et al. (1977)L. aviarius Fujisawa et al. (1984)L. aviarius subsp. aviaries Gusils et al. (1999)L. aviarius subsp. araffinosusL. brevis Russell (1979)L. casei Kandler and Weiss (1986); Salminen et al. (1993); Ahrne et al. (1998); Holzapfel et al (2001)L. crispatus Tannock et al. (1990); Du Toit et al. (2001)L. delbruecki Russell (1979)L. coryniformis Lin and Savage (1984)L. curvatusL. fermentum subsp. cellobiosus Gusils et al. (1999)L. animalisL. gallinarum Fujisawa et al. (1992)L. johnsoniiL. gasseri Klein et al. (1998); Fujiwara et al. (2001) L. fermentum Fuller et al. (1978); Barrow et al. (1980); Morishita (1982);

Hautefort et al. (1996) L. intestinalis Du Toit et al. (2001)Lactobacillus gastricus Roos et al. (2005)Lactobacillus antriLactobacillus kalixensisLactobacillus ultunensisL. murinus Ma et al. (1990)L. plantarum Russell (1979); Bengmark (1998); Du Toit et al. (2001)L. rhamnosus Holzapfel et al. (2001)

L. reuteri Tannock et al. (1982); Sara et al. (1985);Molin et al. (1992, 1992a); Holzapfel et al. (2001)

L. ruminis Sharpe et al. (1973)

L. salivarius Fuller (1973); Barrow et al. (1980); Sara et al. (1985); Rada and Vorisek (1996); Du Toit et al. (2001); Holzapfel et al. (2001)

Lactobacillus thermotolerans Niamsup et al. (2003)L. vitulinus Sharpe et al. (1973); Tannock et al. (1982)

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use, the following conditions are essential:a) host specificity of the strains used, andb) their ability to form stable populationsin the GIT. Attachment of the strain to theintestinal mucosa is one of the selectioncriteria for probiotic microorganisms. Ad-hesion or close association of potentiallyprobiotic LAB, including lactobacilli to epi-thelial cells may further contribute to com-petitive exclusion (CE) (Gusils et al.,2002a).

Some strains of lactobacilli inhabitingthe GIT of animals exhibit a particularlyintimate association with their hosts. Thelactobacilli colonize the proximal region ofthe human small intestine at population lev-els that are minor (<108 g-1) when com-pared to the colonic flora (1010 g-1) wherebifidobacteria are predominant members

(109 g-1). Tissue-associated lactobacillihave been found on the gastrointestinal sur-faces of many animal species. Lactoba-cilli adhere to and multiply on the strati-fied squamous epithelial cells of the proxi-mal small intestine in animals (rodents, pigsand fowl), and are continually shed intothe lower regions of the tract (Pedersenand Tannock, 1989; Tannock, 1990). Inmice, for example, lactobacilli inhabit thetissue surface the esophagus and fore-stomach (Tannock, 1992). In rats, lacto-bacilli colonize the fore-stomach(Brownlee and Moss 1961, Savage, 1977).In fowl, they inhabit the epithelial surfaceof the crop (Fuller and Turvey, 1971; Fuller,1973, 1975, 1978). In pigs, lactobacilli colo-nize the epithelial surface of the esopha-gus and of a small area of tissue in the


Table 2Clasification of Lactobacillus spp.

Group I:Obligately homofermentative -(15 species).

Hexoses are almost exclusively ( <85%) fermented to lactic acid by the Embden-Meyerhov-Parnas (EMP) pathway. The organisms possess fructose 1,6-bisphos-phate-aldolase but lack phosphoketolase, and therefore, neither gluconate nor pentoses are fermente

Group II: Facultative heterofermentative -(11 species)

Hexoses are almost exclusively fermented to lactic acid by the RMP pathway. The organisms possess both aldolase and phosphoketolase, and therefore, not only ferment hexose but also pentoses (and often gluconate). In the presence of glucose, the enzyme

Group III: Obligately heterofermentative - (18 species)

Hexoses are fermented by the phosphogluconate pathway yielding lactate, ethanol (acetic acid) and CO2 in equimolar amounts. Pentoses enter this pathway and may be fermented.

* Kandler and Weiss (1986); Du Toit et al. (2001)

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stomach - pars esophagea (Fuller et al.,1978; Barrow et al., 1980). Under naturalconditions, lactobacilli colonize epithelialsurfaces in mice, rats, fowl and pigs soonafter birth (hatching). Lactobacilli attainhigh population levels on the epithelial sur-face (of the order of 108 bacteria per gramof sample) and a layer of lactobacilli,sometimes several cells thick, is presenton the tissue surface throughout the host’slife. The lactobacilli are shed from the colo-nized surface and can be detected through-out the remainder of the animal’s diges-tive tract (Tannock, 1990).

Specificity of colonization. There areseveral indications in the literature that thecolonization ability of lactobacilli is hostspecific (Lin and Savage, 1984; Tannockand Archibald, 1984; Conway andKjelleberger, 1989; Gusils et al., 2002).The host specificity of epithelium-associ-ating strains has been demonstrated in bothin vitro and in vivo experiments (Fuller,1973; Suegara et al., 1975; Kotarski andSavage, 1979; Wesney and Tannock, 1979;Barrow et al., 1980; Fuller and Brooker,1980; Tannock et. al., 1982). Mitsuoka(1969) observed differences between theadhesion characteristics of L. acidophi-lus strains isolated from man and animals.Morishita et al. (1971) found that L. aci-dophilus isolated from a human IT couldnot be implanted in the IT of a chick.Gilliland et al. (1980) compared two L.acidophilus strains for their use as a di-etary adjunct for young calves. They foundthat the L. acidophilus strain of calf ori-gin was more effective as a dietary ad-junct in calf than the strain of human ori-gin. According to Tannock (1990), severalfactors are likely to be involved in this phe-nomenon:

• Lactobacilli isolated from fowl adhere only to

crop epithelial cells, not to cells from the rat fore-stomach in in vitro experiments in which the bacte-ria have been cultivated in a standard laboratorymedium. Rat isolates of lactobacilli cultured in thesame standard medium adhere only to epithelialcells from rats. Bacterial strains from different hostscultured under the same physiological conditionsthus exhibit host specificity, which suggests thatinteractions occur between specific adhesins andreceptors on bacterial and host cells.

• The stratified, squamous epithelia lining theproximal digestive tracts of fowl, pigs, and rodentsdiffer in chemical composition. The murine fore-stomach, for example, has a keratinized epithe-lium, whereas the chicken crop does not. Lactoba-cilli may have to be nutritionally adapted to in-habit certain types of epithelial surfaces.

• Physiological conditions, including the na-ture of the diet, may influence the colonization ofepithelial surfaces by lactobacilli. Although clearlymarked differences in diet affect the compositionof the normal microflora of the gastrointestinal tract,investigation of subtle physiological differences onintestinal microbes has proved technologically dif-ficult.

This indicates that a Lactobacillusstrain isolated from indigenous microfloraof one animal species will not necessarilycolonize the same site in another animalspecies. Beside the animal species speci-ficity for adhesion, one can also recognizestrain specificity within the bacterial spe-cies. Barrow et al. (1980) demonstratedthat the degree of adherence to squamousepithelial cells of the stomach of pigs wasdifferent for various strains within the samespecies of lactobacilli. This may be causedby the fact that some Lactobacillus spp.do not consist of genetically homologousgroup. For example, according to DNA-hybridization techniques, L. acidophilusforms a heterogeneous group of bacteria(Johnson et al., 1987). Host-species speci-ficity of the intestinal microflora has also

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become clear from characterization stud-ies (differences in biotypes, serotypes andplasmid patterns). In a study by Convayet al. (1987), the tested lactic acid bacte-ria showed comparable adhesion patternsfor human and pig ileal cells. On the otherhand, it is not surprising that Mayra-Makinen et al. (1983) showed that lacto-bacilli from plant and cultured milk andcheese did not adhere in vitro to epithelialcells of pigs and calves.

Although many strains of lactobacilli donot associate with epithelial surfaces andmany animal species do not demonstratethe phenomenon of epithelial colonizationby microbes, the tissue-associating lacto-bacilli provide a useful focus for furtherdiscussion of the microecology of gas-trointestinal lactobacilli.

Mechanisms of colonization. In recentyears there has been increasing interestin the phenomenon of microbial attach-ment to surfaces as an ecological deter-minant (Tannock, 1990; Salminen et al.,1996). Adhesion of lactobacilli to epithe-lial surfaces in the beginning of the coloni-zation process for some strains of lacto-bacilli in the GIT. Anchored to the sur-face of an epithelium, these lactobacilli areable to resist the flushing action of the rela-tively rapid flow of digest passing throughthe proximal digestive tract. Successfulcolonization by any strain of lactobacillus,however, depends on the metabolic abilityof the microbe to function in the GE(Tannock, 1990, 2002).

Adhesion can be non-specific, basedon physicochemical factors, or specific in-volving adhesin molecules on the surfacesof adhesive bacteria and receptor mol-ecules on epithelial cells (Salminen et al.,1996). Earlier studies using animal systemsshown that lactobacilli colonize intestinal

surfaces by adsorption to gastric epithe-lial cells (Fuller, 1973; Savage, 1979;Kotarski and Savage, 1979). This physi-cal association with epithelial surfaces isan important criterion in determining theability of the organism to colonize the gut.Many investigations have reported thepresence of a surface layer in certain lac-tobacilli exterior to the cell wall and its in-volvement in the adherence of these or-ganisms to the gastrointestinal tract(Brooker and Fuller, 1975; Masuda andKawata, 1980, 1981; Hood and Zottola,1987). Subsequent research has shownthat this layer is composed of protein sub-mits that bind to the neutral polysaccha-ride moiety of the wall, other than pepti-doglycan or teichoic acid, probably throughH-bonding (Masuda and Kawata, 1980,1981; Sleytr and Messner, 1983; Hood andZottola, 1987). Being on the surface, theseproteins are presumably directly involvedin the interactions between the cell and itsenvironment.

Bhowmik et al. (1985) demonstratedthe presence of a surface protein layer insome L. acidophilus strains and partiallycharacterized it. The surface protein wasresistant to hydrolysis by several pro-teolytic enzymes, suggesting that the layermay have a protective function. L. acido-philus exhibited in high degree of hydro-phobicity, and this property was depend-ing on the surface protein. Therefore, theytheorized that the surface layer might havea role in the attachment of these organ-isms to the intestinal mucosa. Schneitz etal. (1993) observed that the surface layerformed the outermost part of the cell wallin strongly adherent L. acidophilusstrains, whereas this layer was coveredwith polymerized material or was absentin strains that lacked the ability to adhereor those with reduced adherence.


Fuller and Brooker (1980) suggestedthat the adherence of lactobacilli to epi-thelial cells is a multistage process fromthe initial phase of electrostatic attractionto the formation of fibrils and microcap-sules. They theorized that the outermostsurface layer is a potential mediator of theinitial steps in adherence. Further, adher-ence is not only a mechanical tie betweenepithelial cells and bacteria but are alsoan active process that probably elicits ametabolic response in both (Hoepelmanand Tuomanen, 1992).

Coconnier et al. (1992) proposed amodel for the adherence of L. acidophi-lus BG2 F04 to human intestinal cells. Themechanism involves two factors: the bac-terial cell-wall factor and the adhesion-pro-moting factor. The bacterial cell-wall fac-tor is polysaccharide in nature and is re-sponsible for the interaction between thebacterium and the extracellular adhesion-promoting factor. Earlier, Brooker andFuller (1975) had also reported that thesurface layer was rich in carbohydrates.Later, Hood and Zottola (1987) observedthat the adherence was mediated by apolysaccharide located at the bacterial sur-face. The second factor, adhesion-promot-ing factor, is an extracellular proteinaceouscomponent produced by adhering lactoba-cilli and provides a divalent bridge that linksthe bacteria to the intestinal enterocyte.This classic work has provided conclusiveevidence about the factors involved in theadherence of lactobacilli to the IT and theirchemical nature. For more informationabout adhesion ability of lactobacilli seeTuomola and Salminen (1998); Tuomolaet al. (2001); Tannock (2002); Gusils etal. (2002).

FUNCTIONS OF LACTOBACILLI IN THEGASTROINTESTINAL TRACT

The activities of LAB, especially lac-tobacilli in the GT have interested micro-biologists for at least 90 years, since thetime of Metchnikoff (1903, 1907). Sincethen, there has been much interest andresearch activity focused on the functionsof lactobacilli in the GIT, and on their po-tential health and nutritional benefits. Sev-eral reviews and books related to this topichave been published (Gilliland, 1979, 1990;Sandine, 1979; Shahani and Ayebo, 1980,Nakazawa and Hosono, 1992; Mital andGard, 1995; Tonila, 1996); Tannock, 1995,2002). The most important nutritional andtherapeutic effects of lactobacilli (Gurr,1977; Sandine, 1979; Shahani and Auebo,1980; Fernandes et al., 1987; Gilliland,1990; Mital and Garg, 1995; Denev, 1996,1997; Denev et al., 2000; Tannock, 2002)can be summarized as follows:

• Stimulation of the overall metabolism by pro-ducing vitamins (e.g., folic acid) and enzymes (e.g.lactase);

• Stabilization of the intestinal microflora, ex-cluding colonization by pathogenic bacteria suchas Staphylococcus aureus, Salmonella spp., Shi-gella spp. and enteropathogenic E. coli strains, viaadhesion to the intestinal wall and competition fornutrients;

• Control of growth of undesirable organismsin the intestinal tract and protection against intes-tinal infections by production of antibacterial sub-stances and competitive exclusion;

• Deconjugation of bile acids;• Reduction of the cholesterol level in blood

serum by cholesterol assimilation, bile salt hydroly-sis and/or modulation of the ratio of high-densityto low-density lipoproteins/cholesterol;

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• Decreased risk of colon cancer by detoxifi-cation of toxic, mutagenic and carcinogenic com-pounds and modulation of fecal procarcinogenicenzymes such as b-glucuronidase, azoreductase andnitroreductase;

• Tumor suppression via aspecific stimulationof the immune system.

Control of Growth of UndesirableOrganisms in the Intestinal Tract

Antagonistic Effect

It is well known that the presence oflactobacilli is important for the mainte-nance of the intestinal microbial ecosys-tem (Denev et al., 2000). The potentialcontrol of intestinal pathogens by LAB hasreceived much attention for the past 90years. Since Metchnikoff (1903, 1907)proposed a role of lactobacilli in suppress-ing undesirable intestinal microflora, nu-merous researchers have investigated theantagonistic activities of lactobacilli (re-viewed by Lindgren and Dobrogosz, 1990;Klaenhammer, 1988, 1993; Boris et al.,2001; Bird et al., 2002).

Several investigations have shown thatLactobacillus spp. exerts antagonistic ac-tion against intestinal and food-bornepathogens and other related organisms(Grossowics et. al, 1947; Wager, 1948;Wheater et al., 1951, 1952; Polonskaya,1952; Vincent et al., 1959. De Klerrk andCoetzee, 1961; Tramer, 1966; Reddy andShahani, 1971; Hamdan and Mikolajcik,1973; Mikolajcik and Hamdan, 1975; Tagget al., 1976; Shahani et al., 1976, 1977;Lascar, 1995; Singh et al., 1995; Denev etal., 2000; Bird et al., 2002). They havebeen shown to possess inhibitory activitytoward the growth of pathogenic bacteriasuch as Listeria monocytogenes (Harris

et al., 1989), E. coli, Salmonella spp.(Drago et al., 1997), and others (Coconnieret al., 1997).

Gilliland and Speck, 1977 were amongthe first investigators reporting on antibac-terial activity associated with Lactobacil-lus spp. Numerous reviews and books ad-dressing this field have recently been pub-lished (McCormick and Savage, 1983;Barefoot and Klaenhammer, 1983, 1984;Reddy et al., 1984; Joerger andKlaenhammer, 1986; Muriana andKlaenhammer, 1987; Wong and Chen,1988; Daeschel, 1989; Geis, 1989;Klaenhammer, 1988, 1993; James et al.,1992; Juven et al., 1992; Piard andDesmazeaud, 1992; Ray and Daeschel,1992; Hoover and Steenson, 1993; Nettlesand Barefoot, 1993; Sudirman et al., 1993;Benoit et al., 1994; De Vuyst andVandamine, 1994; Dodd and Gasson, 1994;Desmazeaud, 1994; Larpent, 1994;Kanatani et al., 1995; De Vuyst et al.,1996; Tahara et al., 1996; Takatoshi et al.,1996; Thanaruttikannont and Rengpipat,1996; Van der Vossen et al., 1996;Ouwehand, 1998; Guilliams,1999; Denev,1996, 1997; Denev et al., 2000; Dunne etal., 2001). This antibacterial activity mayresult not only from decreasing the pH andredox potential, competition for nutrientsand adhesion sites, but also because of theformation of specific antimicrobial com-pounds against Gram-negative and Gram-positive organisms.

The intestinal lactobacilli play a majorrole in the regulation of bacterial popula-tion and the control of various entero-pathogens in the GE. They suppress themultiplication of the pathogenic and putre-factive bacteria that cause intestinal prob-lems, diarrhea and digestive upsets, etc.,and contribute to the maintenance ofhealth. Lactobacilli are consumed by hu-

73Role of Lactobacilli in Gastrointestinal Ecosystem

mans and fed to animals of commercialvalue in efforts to control a variety of dis-eases and to maintain a balanced micro-flora by reduction of potential pathogensresiding in the gut.

It is not the intent of this paper to re-view all of the literature on control of in-testinal pathogens by lactobacilli howevera few examples will be given. Certain Lac-tobacillus strains inhibit E.coli adhesionto porcine enterocytes and attachment toporcine mucus (Ouwehand and Conway,1996). Furthemore, metabolic end prod-ucts of lactobacilli present in cell-free cul-ture supernatant fluids inhibit adhesion orinvasion by pathogenic bacteria. ProbioticLactobacillus strains also inhibit mucosaladherence of EPEC and S. typhimuriumin vitro (Bernet et al., 1994). In additionto prevent colonization by pathogens, Lac-tobacilli may strengthen the epithelial bar-rier, thereby preventing pathogenic trans-location of the epithelium by promoting ac-celerated epithelial repair. For example,oral administration of Lactobacillus aci-dophilus can ameliorate diarrhea in pa-tients undergoing pelvic radiotherapy, per-haps by preventing radiation-induced dam-age to the intestinal epithelium (Kaila etal., 1995). Furthermore, enhanced mac-romolecule intestinal permeability andtranslocation of intact proteins induced bycow milk was reversed in suckling rats fedmilk supplemented with L. casei GG(Salminen et al., 1988).

The exact mechanism whereby lacto-bacilli may inhibit intestinal pathogens isnot clear. Antagonistic factors that maycontribute to colonization and continuouspresence of lactobacilli in the digestivetract of animals are the presence of spe-cific antimicrobial compounds. The an-tagonism could be due to the production ofinhibitory compounds such as organic ac-

ids, hydrogen peroxide, bacteriocins andbroad-range antibiotic-like substances, orto competitive adhesion to the epitheliumand etc.

Bacteriocins and bacteriocin-likesubstances. The discovery of bacterio-cins dates back to 1925, when Gratia ob-served the inhibition of E. coli by E. coliV. The antibacterial substances producedby E. coli were named colicins (Fredericq,1948). The first report of production of an-tagonistic substances other than metabolicend products by LAB was made in 1928by Rogers. He observed antagonistic ac-tivity for L. lactis subsp. lactis against L.delbrueckii subsp. bulgaricus. The sub-stance was determined to be a polypep-tide (Whitehead, 1933) and subsequentlynamed nisin (Mattick and Hirsch, 1947).De Klerk and Coetzee (1961) first isolatedbactericidal substances from 11 homofer-mentative strains and one heterofermen-tative strain of Lactobacillus, that wereonly active against other Lactobacillusspp. and thus could be defined as bacte-riocins. Among the Gram-positive bacte-ria, the lactobacilli in particular produce awide variety of antimicrobial proteins in-cluding peptide antibiotics, antibiotic-likesubstances, bacteriocins and bacteriocin-like substances.

Bacteriocins, as defined by Tagg et al.(1976), are proteinaceous compounds pro-duced by bacteria that have bactericidalactivity against closely related species.They form a heterogeneous group withrespect to producing bacterial species,molecular size, physical and chemical prop-erties, stability, antimicrobial spectrum,mode of action, and so on.

Bacteriocins of LAB have been thesubject of many studies over the past 10years (De Vuyst and Vandamine, 1994;

S. A. Denev74

De Vuyst, 1994, 1996; Cenatiempo et al.,1996). Investigations on bacteriocins havehistorically focused on four general areasthat include: bacteriocin expression, pro-duction and mode of action; characteriza-tion of plasmids encoding bacteriocin pro-duction and immunity and their use as ve-hicles for gene transfer; identification anddescription of novel bacteriocins producedby bacteria not previously recognized asbacteriocinogenic; and taxonomic charac-terization of bacteria based on bacteriocinproduction or susceptibility (Klaenhammer,1988).

Since the late 1920s and early 1930s,when the discovery of nisin initiated theinvestigation of proteinaceous antimicro-bial compounds from LAB, a large num-ber of chemically diverse bacteriocins havebeen identified and characterized, particu-larly in recent years. Nonetheless, we canobserve common traits that justify theirclassification into just a few classes(Klaenhammer, 1993). On a sound scien-tific basis, three defined classes of bacte-riocins in LAB have been established,class I: the lantibiotics; class II: the smallheat-stable non-lantibiotics and class III:large heat-labile bacteriocins (Nes et al.,1996). In the past decades a large num-ber of reports have been published describ-ing Lactobacillus spp. that is claimed toproduce bacteriocin and bacteriocin-likecomponents. A selection is listed in Tab-le 3.

Bacteriocins and bacteriocin-like com-pounds play an important role in control-ling the composition of indigenous microf-lora and the regulation of population dy-namics in various bacterial ecosystems.Since, bacteriocins usually are only activeagainst organisms closely related to theproducer, their role in inhibiting intestinalpathogens may be limited. Bacteriocins ofGram-positive organisms usually possess

a somewhat broader inhibitory spectrumand are also active against other Gram-positive species. However, they may bevery important in enabling a selected strainof Lactobacillus in competing with otherLAB in the intestines. Some bacteriocinsas acidolin, acidophilin, bulgarican andreuterin have been reported to possess amuch broader inhibitory spectrum: manyGram-positive and Gram-negative bacte-ria were said to be inhibited by the puri-fied products (Shahani et al.,1977; Fernan-des et al., 1987; Talarico et al., 1988;Axelsson, 1989; Chung et al., 1989; Tala-rico and Dobrogosz, 1989). Certainly thesetypes of bacteriocins may be very effec-tive in helping to control the growth of in-testinal pathogens (Gilliland, 1990). Formore information about general charac-teristics, mechanisms of action, geneticsand biosynthesis of bacteriocins see Fuller(1992), Klaenhammer (1993), De Vuystand Vandamme (1994), Mishra and Lam-bert (1996), Nes et al. (1996), Tannock(2002).

Recently, bacteriocins have been stud-ied intensively from every possible scien-tific angle: microbiology, biochemistry, mo-lecular biology and food technology.Knowledge, especially about bacteriocinsfrom lactobacilli, is accumulating very rap-idly. Future investigations of bacteriocinshave provided new information in each ofthese areas.

Other antagonistic compounds. An-tagonism by lactobacilli has also been as-sociated with major end products of theirmetabolism. Several by-products of lac-tobacillus metabolism are capable of an-tagonism in vitro and in vivo. The bestknows of these compounds are lactic andacetic acids, hydrogen peroxide, diacetyland etc.

Organic acids such as lactic and ace-


tic which are responsible for significant pHchanges in gut-sufficient to antagonizemany microorganisms, including patho-genic Gram-negative organisms (Adamsand Hall, 1988). While pH per se is a fac-tor in such inhibitions, lower pH values alsopotentate the activities of these acids be-cause undissociated forms are more bac-tericidal than dissociated ones. This phe-

nomenon may be attributed to the abilityof undissociated acids to penetrate thebacterial cell (Kashet, 1987). Further, thevolatile acids are especially antimicrobialunder the low oxidation-reduction poten-tials that lactobacilli help maintain in theintestine (Goepfert and Hicks, 1969;Tannock, 2002). Organic acids decreaseor kill harmful bacteria, and as a result sup-

S. A. Denev76

Table 3

Species Bacteriocin References

L. acidophilus Lactocidin Vincent et al. (1959)Acidophilin Vakil and Shahani (1965)Acidolin Hamdan and Mikolajcik (1973)Lactacin B Barefoot and Klaenhammer (1983)Lactacin F Muriana and Klaenhammer(1987, 1991)

Klaenhammer et al. (1993)

Bacteriocin M46 Ten Brink et al. (1990)Acidophilucin A Toba et al. (1991)Acidocin A Kanatani et al. (1992, 1995)

L. brevis Lactobrevin Kavasnikov and Sudenko (1967)Brevicin Rammelsberg and Radler (1990)

L. casei Caseicin 80 Rammelsberg et al. (1990)Disks et al. (1992)

L. delbrueckii subsp. lactis UO004 Bacteriocin UO004 Boris et al. (2001)

L. fermentum Bacteriocin 466 De Klerk and Coetzee (1961)

L. gasseri Gassericin A Toba et al. (1991a)Takatoshi et al. (1996)

L. plantarum Lactolin Kodama (1952)Plantacin A Daeschel et al. (1990)Plantacin B West and Warner (1988)Plantacin S Jumenez-Diaz et al. (1993)Plantacin D Aymerich et al. (2000)Plantacin T Jumenez-Diaz et al. (1993)Plantacin Y Chin et al. (2001)

L. reuteri Reutericin 6 Toba et al. (1991b)

L. salivarius Salivaricin B Ten Bring and Holo (1996)

Bacteriocins and bacteriocin-like substances of some intestinal Lactobacillus species

Table 4

Substrates, reaction Catalyzed by End Products References

Pyruvate + O2 + phosphate Pyruvate oxidaseAcetyl phosphate +

CO2 + H2O2

Gotz et al. (1980) Murphy and Cobdon (1984)

Lactate + O2 L-lactate oxidase Pyruvate + H2O2 Kandler (1983)

Lactate + O2NAD-independent

D-lactate dehydrogenasePyruvate + H2O2 Sedewitz et al. (1983)

Saturated fatty acids + O2 Fatty acyl- CoA H2O2 De Kairuz et al. (1988)

-Glycerophosphate + O2 -Glycerophosphate

oxidaseDihydroxyacetone phosphate + H2O2

Condon (1987)

Substrates and reactions that might lead to production of H2O2 by Lactobacilli

press the production of harmful substancessuch as amines, phenols, indole, scatoleand hydrogen sulphide which are producedby these harmful bacteria. Because manyof these harmful bacteria have a neutraloptimum pH and are not acid-tolerant, thelowering of pH by organic acid metabo-lites of lactobacilli, such as lactic acid, hasa bacteriostatic or bactericidal effect onthese acid-sensitive bacteria (Fuller, 1992).

Hydrogen peroxide (H2O2) is one ofthe primary metabolites produced by lac-tobacilli. The lactobacilli have the abilityto generate hydrogen peroxide duringgrowth by several different mechanisms(Table 4.).

The accumulation of hydrogen perox-ide in growth media is shown in occursbecause lactobacilli do not possess thecatalase enzyme (Kandler and Weiss,1986). The antimicrobial activity of hydro-gen peroxide is well recognized and docu-mented. This compound is cytotoxic be-cause of its capacity to generate reactive

cytotoxic radicals that are strongly oxida-tive (Halliwell, 1978). Lactobacilli usuallyproduce hydrogen peroxide by direct re-duction of oxygen. Aside from the gen-eration of hydroxyl radicals, the in vivobactericidal effects of hydrogen peroxidemay be relevant to the activation of a per-oxidase-hydrogen peroxide system, com-monly referred to as lactoperoxidase sys-tem. A well-studied lactoperoxidase sys-tem is described in milk, where bacteri-cidal activity against enteric Gram-nega-tive bacteria is associated with thiocyan-ate (Reiter and Harnulv, 1984). Thismechanism may also occur in the intes-tines (Retire et al., 1980; Fervidness et al.,1987). Lactobacilli stimulated the lactop-eroxidase thiocyanate system in the intes-tines, which reduced the ability of E. coliand other enteropathogens to survive inthe gut (Fernandes and Shahani, 1989).

Hydrogen peroxide production by lac-tobacilli will usually occur by direct reduc-tion of atmospheric oxygen catalysed by


α α

77

either pyruvate-, NADH, alpha-glycero-phosphate-oxidase (Condon, 1987) or lac-tate-oxidase. In phosphate buffer with glu-cose and pyruvate added, resting cell of astrain of L. acidophilus, isolated from thechicken GT, produced 280 nmol hydrogenperoxide per hour per milligram of cell dryweight. Concentrations of oxygen highenough for significant amounts of hydro-gen peroxide to be produced are likely toexist only in the upper portions of the GITof live animals. That might be one of theexplanations for the antagonistic effectsof lactobacilli towards salmonellas ob-served in the crop of chicks whereas noneor very limited antagonism was found intheir caeca (Juven et al., 1991). For moreinformation abou antimicrobial compoundsproduced by lactobacilli and their struc-tures and properties see Yang (2000).

COMPETITIVE EXCLUSION OF PATHO-GENIC BACTERIA BY LACTOBACILLI

One of the physiological effects of lac-tobacilli in the host has proposed to be theantagonism against pathogens. Competi-tive exclusion (CE) by the lactobacilli isanother mechanism that has been sug-gested as being important in controlling in-testinal infections (Watkins and Miller,1983a; Edens et al., 1997; Edelman, 2005).CE involves the ability of the lactobacillito occupy binding sites on the intestinalwall, thereby preventing attachment andgrowth of enteric pathogens.

Nurmi and Rantala (1973) first recog-nized the importance of early establishmentof protective microflora in young chicks.Originally, these workers treated chickswith a suspension of crop and intestinaltract materials obtained from adult birds;in subsequent studies, cecal content or fe-ces cultures anaerobically in a liquid me-

dium were used for treatment. Thesepreparations of unknown bacterial com-position were administered orally to day-old chicks, which were challenged 24 or48 h later with a standardized dose of Sal-monella. Results showed that such treatedchicks were more resistant to infectionthan control birds. This prophylactic ap-proach, known as the “Nurmi concept” or“competitive exclusion”, opened new ho-rizons for the control of Salmonella inpoultry.

The advent of CE technologies for thecontrol of pathogenic enteric bacteria inpoultry as well as humans has receivedconsiderable interest during the past twodecades. Intensive efforts by groups ofUSDA scientists (Bailey, 1988; Ziprin etal. 1991; Corrier et al., 1994, 1995a, 1995b;Hollister et al., 1995) signal the importanceof this technology and its application to thepoultry industry. The mechanisms used byone species of bacteria to exclude or re-duce the growth of another species arevaried, but Rolfe (1991) determined thatthere are at least four major mechanismsof CE. These mechanisms are: 1) creationof microecology that is hostile to other bac-terial species; 2) elimination of availablebacterial receptor sites; 3) production andsecretion of antimicrobial metabolites, and4) selective and competitive depletion ofessential nutrients.

The effect of CE lactobacillus cultureson the growth of undesirable organisms inthe IT has been well documented the lastdecade. Watkins et al. (1979, 1982) re-ported that broiler chicks inoculated withL. acidophilus were more resistant to thepathogenic effect of E. coli. The additionof L. acidophilus acidified the crop,cecum and colon of the inoculated chicks,and this acidification appeared to increasethe competitiveness of the L. acidophi-

S. A. Denev78

lus against the other intestinal microflora.Watkins and Miller (1983a) suggested thatL. acidophilus increases competitive gutexclusion against harmful organisms (S.typhimurium, Staphylococcus aureus,and E. coli) in the intestinal tract. Watkinsand Miller (1983b) demonstrated that L.acidophilus colonized the epithelial cellsof the GIT through a close relationship andthrough actual physical attachment.

With the discovery that L. reuteri is amajor component of the intestinal microf-lora of humans (Gibson et al., 1997),chicks and other animals (Sarra et al.,1985; Dobrogosz et al., 1991; Edens et al.,1993; 1997) is appeared that the popula-tion dynamics of L. reuteri might be in-volved in establishing a favorable micro-ecology in the IT via its ability to secretelactic and acetic acid, and reuterin, whichact as modulators of intestinal tract mi-crobial populations (Dobrogosz et al.,1991).

According to Soerjadi et al. (1981a,1981b) members of the Lactobacillaceaefamily are responsible for CE of patho-gens from the gut of chicks. Schneitz etal. (1993) demonstrated the importance oflactobacilli with the ability to adhere as CEmicroorganisms in poultry. Mulder et al.,(1997) also reported that Lactobacillusspecies are very important in establishinga stable GIM which is able to prevent colo-nization of potentially pathogenic micro-organisms. Therefore, the use of probioticsand other CE products containing intesti-nal Lactobacillus spp. may be also exerta positive effect against this colonization.

Lactobacilli have been shown to affectthe prevalence of several intestinal patho-gens in vitro and in vivo (Coconnier etal., 1998; Jin et al., 1996; Pascual et al.,1999; Mack et al., 1999; La Ragione etal., 2004). The detailed molecular mecha-

nisms underlying this phenomenon remainpoorly characterized, and the reports varyin degrees of successful inhibition depend-ing on the strains used as CE agents, thepathogens as well as the methods of as-sessment. The importance of adhesion inpathogen exclusion at chicken ileal epitheliahas been shown in vitro with L. acido-philus against Salmonella pullorum (Jinet al., 1996) but L. acidophilus failed toexclude Salmonella enterica serovarEnteritidis and Salmonella entericaserovar typhimurium and APEC (Jin etal., 1996, 1998). Also, exclusion of E. coliand salmonalla by lactobacilli in human andpiglet mucus have been reported (Lee etal., 2003), but lactobacilli failed to inhibitthe adhesion of Salmonella ssp. to chickenmucus (Gusils et al., 2003). L. crispatusand its collagen binding S-layer protein in-hibit the adherence of E. coli to the com-ponents of basement membrane (Horie etal., 2002) and a 29-kDa surface proteinfrom L. fermentum inhibited adhesion ofuropathogenic Enterococcus faecalis topolystyrene (Heinemann et al., 2000). Formore information about CE properties oflactobacilli see (Edens et al., 1997; Mulderet al., 1997; Edelman, 2005). Improvingour understanding of the development andthe regulatory mechanisms of the lacto-bacillus flora in GE is essential for the de-velopment of effective CE products forhumans and animals.

NEUTRALIZATION OF TOXINS ANDOTHER INTESTINAL REACTIONS

Among the intestinal bacteria thereare some which act on food componentsand digestive secretions like bile acids toproduce harmful putrefactive productssuch as enterotoxins, ammonia, amines,phenols, indole and hydrogen sulphide, or


other toxic and carcinogenic substances.If these harmful metabolites are producedin large quantities, they promote a decreasein liver function and the development ofcancer.

Intestinal lactobacilli have been shownto inhibit the growth of pathogenic bacte-ria, decrease the metabolic activity ofharmful bacteria, including production ofenzymes which contribute to the produc-tion of toxic and cancer-related substances(Mitsuoka, 1984; Honma, 1986). Intesti-nal lactobacilli can also suppress the pro-duction (Honma et al., 1987) and break-down of nitrozamines, which have beenshown to be connected with the develop-ment of stomach cancer and cancer of thesmall intestine (Kanbe, 1992).

Investigations of L. bulgaricus in pigsshowed that the organism produces a me-tabolite thought to neutralize the effect ofenterotoxin released from coliforms. Pig-lets fed a L. bulgaricus culture, renderednon-viable with lactic acid, and artificiallyinfected with E. coli, grew faster and suf-fered less diarrhea compared with controlanimals. These studies showed that somelactobacilli especially L. bulgaricus wasable to neutralize E. coli enterotoxin(Mitchel and Kenworthy,1976). Althoughthe neutralizing substance has yet to beidentified, further support for anti-enterotoxic activity has also been obtainedfrom experiments with rats and calves. Cellfree extracts of L. casei and L. acido-philus have also been shown in vitro toinhibit the growth of E. coli. Scheline(1972) tested a number of different sub-strates and intestinal microorganisms todetermine the type of reactions specificLactobacillus species catalyze. In thestudy cited above, these investigators foundthat a Lactobacillus species could reducethe double bond in hydroxycinnamic acid,

reduce the nitro group of 4-nitrobenzoicacid and reduce the azo bond found inmethyl red and acid yellow. In more re-cent publication Pradham and Majumdar(1986) reported that L. acidophiluscleaves the azo bond of sulfasalazine, alsoknown as azulfidine, a drug used to treatpatients with ulcerative colitis. These in-vestigators also found that L. acidophi-lus degraded 17.6% of the antimicrobialagent phthalylsulfathiazole and 8% of theantibiotic chloramphenocol palmitate.These investigators also confirmed theprevious study and demonstrated that L.acidophilus could rapidly hydrolyze theazo bound of tartrazine and methyl red.L. helveticus and L. salivarius also hadsimilar but lower activity when comparedto L. acidophilus. Lactobacilli have alsobeen shown to reduce the double bond of3-hydroxy cinnamic acid and cinnamic acid(Whiting and Carr, 1970) to produce re-spectively 3-hydroxy phenylproponic acidand phenylproponic acid. A Lactobacil-lus species has been shown to be capableof amino acids (Melnoykowycz andJohansson, 1955). A L. acidophilus iso-lates from the stomach of rat was shownto exhibit histidine decarboxylase activity(Horakova et al., 1971).

Nitrosamines have been shown to bepotent carcinogens (Magee, 1971). The ni-trosamines found in foods are dimethyl-nitrosarnine, diethylnitrosamine, N-nitrosopyrrolidine, and N-nitro-sopi-peridine. These are formed when nitritesreact with secondary amines in an acidicmedium (Hawksworth and Hill, 1971).Nitrites are derived from nitrates, whichare found in green plants, vegetables, curedmeats, and some cheese products (Enderand Ceh, 1968). Nitrates may also bepresent in drinking water in higher con-centrations (Correa et al., 1970). A rela-

S. A. Denev80

tionship between gastric cancer and highnitrate intake has also been suggested(Correa et al., 1970). Lactobacillus spe-cies could degrade nitrosamines and thusmitigate their toxical and carcinogenic ef-fect (Rowland and Grasso, 1975; Kanbe,1992).

Some lactobacilli (L. acidophilus)have been shown to suppress the produc-tion of harmful substances such as am-monia, indole and hydrogen sulfide, whichare hazardious to the body. This suppress-ing effect may help to decrease the amountof toxins going to the liver and injuring it(Yamamoto et al., 1986; Yamashita et al.,1987).

Lactobacilli reduced activities of fecalbacterial enzyme b-glucuronidase, nitro-reductase, and azoreductase (Goldin andGorbach, 1984) that are involved in pro-carcinogen activation and reduced excre-tion of mutagens in feces and urine(Lidbeck et al., 1992).

These studies demonstrated the poten-tial of lactobacilli as toxin neutralizers, in-hibitors of cancer promoting enzyme ac-tivity, destructors of fecal nitrosamines andother drugs, harmful, mutagenic and car-cinogenic substances in the GIT.

DECONJUGATION OF BILE ACIDS

Bile acids are synthesized from cho-lesterol in the liver, conjugated to eitherglycine or taurine, and then released intothe intestines, where they facilitate fat ab-sorption by the epithelial cells (Hofmannand Mehjian, 1973). These acids aredeconjugated, dehydroxylated, dehydroge-nated, and desulfated in the intestines bymicrobial enzymes (Hylemon and Glass,1983). The capacity to deconjugate bileacids (hydrolyze the amide bond betweenthe steroid nucleus and amino acid) is wide-

spread among members of the autochtho-nous gastrointestinal microflora (Hayaka-wa, 1973; Midtvedt, 1974), including spe-cies of the genera Bacteroides (Masuda,1981), Bifidobacterium (Ferrari et al.,1980; Grill et al., 1995), Clostridium(Masuda, 1981), Lactobacillus (Gillilandand Speck, 1977a; Christiaens et al, 1992;Tannock et al., 1994), Fusobacterium(Shimada et al., 1969), Streptococcus(Kobashi et al., 1978) and others species(Midtedt, 1974). The reaction is catalyzedby the enzyme bile salt hydrolase (BSH)(Lundeen and Savage, 1990).

BSH catalyze the cleavage of an aminoacid from the steroid nucleus of conjugatedbile salts. It is not clear why lactobacilliproduce an enzyme with this property, be-cause they would not gain energeticallyfrom the deconjugation process, but it maybe an essential property enabling the bac-teria to survive transit through the smallbowel, into which relatively high concen-trations of conjugated bile acids are re-leased (De Boever and Verstraete. 1999).The deconjugating activity of the lactoba-cilli could be important to the host, becausedeconjugated bile salts are less effectivein emulsification of dietary lipids and mi-celle formation. Thus, the BSH activity oflactobacilli in the small bowel could impairlipid digestion and absorption by the hostand could have implications in the poultryand pig industries, where rapid growth andefficient feed conversion are required forprofitability (Tannock, 2004).

BSH has been purified from three or-ganisms, Bacteroides fragilis (Stellwagand Hylemon, 1976), Clostridiumperfringens (Gopal-Srivastava andHylemon, 1988; Coleman and Hudson,1995) and Lactobacillus ssp. (Lundeen andSavage, 1990, 1992). Lactobacilli havebeen shown to be the predominant pro-


ducers of BSH activity in the mouse gut.Gastric lactobacilli contribute approxi-mately 86% of the total BSH activity andthe 74% in the cecum of mice (Tannocket al., 1989). However, the enzymes cata-lyzing the reaction in these bacteria havenot been extensively studied (Tannock,2004). Hill and Drasar (1968) and Arieset al. (1969) reported that Lactobacillusssp. isolated from human feces were un-able to deconjugate taurocholic acid.Midtvedt and Norman (1968) reported thatL. arabinosus deconjugated both tau-rocholic and glycocholic acids, whereasL. brevis deconjugated only glycocholicacid. L. acidophilus,L casei and L.delbrueckii did not deconjugate either ofthe two bile acids. Floch et al. (1972) iso-lated Lactobacillus species from humanfeces, which deconjugated glycocholic,glycodeoxycholic, and glycochenode-oxycholic acids. The species of lactoba-cillus were not identified.

Gilliland and Speck (1977a) examineda number of lactobacilli from human fe-ces for their ability to deconjugate bileacids. They found that all of them pos-sessed this capacity but acted on either atauro- or glycoconjugate. However, onlyL. buchneri among the lactobacilli testedacted upon both.

The bile acids excreted in feces are en-tirely deconjugated. They represent about5% of the enterohepatically circulatedpool and consist of a variety of second-ary bile acids in addition to small quanti-ties of primary bile acids (Mallory et al.,1973). The deconjugated bile acids exerta greater inhibitory action against bacte-ria than conjugated forms (Dunne et al.,2001).

Deconjugated bile acids, particularlydehydroxy acids (deoxycholic and cheno-deoxycholic acids) inhibit the growth of a

variety of intestinal bacteria (Binder et al.,1975). Further, dihydroxy bile acids aremore inhibitory than trihydroxy one- cholicacids (Floch et al., 1972). Percy-Robb andCollee (1972) observed that the in vitroantibacterial actions of bile acids werestrongly pH dependent. They suggestedthat bile acids might be involved in a self-regulatory mechanism that prevented mi-crobial colonization of the upper bowel.

Bacterial metabolism of bile acids hasbeen postulated to play an important rolein etiology of colon cancer (Hill, 1986). Itis suggested that the secondary bile acids(i.e. those resulting from bacterial metabo-lism) can act as promoters of the tumo-rogenic process in the colon. In addition,Hill has proposed that dehydrogenation ofthe steroid nucleus to produce delta 1 anddelta 4 bonds in association with 3-ketogroups is particularly important in relationto colon cancer. Certain strains can per-form this reaction in vitro although the sig-nificance of the reaction in vivo is ques-tionable (Lombardi et al., 1978).

Deconjugated bile acids by lactobacilliplay a significant role in maintaining eco-logical equilibrium in the intestine (Hochet al., 1972; Mital and Garg, 1995;Tannock, 2004) They are more inhibitoryto bacteria than conjugated ones (Percy-Robb and Collee, 1972); therefore,deconjugation of bile acids may enhanceantagonistic actions of intestinal lactoba-cilli toward intestinal pathogens, thus help-ing to maintain a favorable balance amongspecies present in the intestinal tract. Sev-eral reports have been published on thistopic during the last years (Charteris etal., 1998; Boever and Verstaete, 1999; Grillet al., 2000; Shinoda et al., 2001; Tannock,2004). Understanding of the structural,enzymatic, and regulatory properties of thehydrolases from lactobacilli will be impor-

S. A. Denev82

tant to understanding of the role of theseorganisms in bile acid transformations inthe GIT.

Much attention has recently been paidto the phylogeny of the gut microbiota, butlittle has been paid to the microbial physi-ology of complex bacterial communities ortheir individual components (Lu et al.2003). It is time that this imbalance wasrectified. Lactobacilli could provide modelbacteria for such physiological studies be-cause their relationship with the farm ani-mal host (chickens, pigs) is much betterdefined than that of other members of themicrobiota.

ANTIMUTAGENIC ACTIVITY

Bruce et al. (1977) was the first to re-port the presence of mutagenic compoundsin human feces. Since then, many re-searchers have investigated the occur-rence and levels of fecal mutagens in dif-ferent populations (Ehrich et al., 1979;Reddy et al., 1980; Ferguson et al., 1985).Mutagenic activity in feces has been re-ported to be promoted by bile, enhancedby anaerobiosis, and inhibited by exposureto oxygen (Lederman et al., 1980; VanTassell et al., 1982a).

Studies with pure cultures have shownthat Bacteroides fragilis, B. ovatus, B.uniformis, and B. thetaiotaomicron arecapable of producing mutagens (VanTassell et al., 1982b). The fact that theseorganisms are common inhabitants of theintestinal tract and that only a relativelysmall percentage of individuals produce themutagen indicates that a precursor is thedetermining factor in their production. Ithas been demonstrated that bacteria fromfeces that do not contain the mutagen arecapable of producing it in the presence ofa precursor. The precursor is either a prod-

uct of other intestinal bacteria, a result ofa diet, or a metabolite derived from thehost. Further, it has been shown that cell-free extracts of bacteroides can producethe mutagen in the presence of bile. Theenzyme system involved is not oxygensensitive (Mital and Gard, 1995). However,the mutagen is only produced anaerobi-cally (Wilkins et al., 1981).

It is well known that carcinogenesis isinitiated by mutation induced in animal andhuman cells with carcinogen. Several com-pounds displaying mutagenic propertieshave been identified in numerous foods(Hosono, 1992; Thyagaraja and Hosono,1993).According to McCann et al. (1975)mutagenicity and carcinogenicity showgood correlation.

Recently, attention has been focusedon the biological transformation of sub-stances to carcinogens by intestinal micro-flora. Studies on the conditions that en-hance or decrease the activation or inac-tivation of environmental mutagens are im-portant for the control of their risks to hu-man (Thyagaraja and Hosono, 1994).There is evidence that LAB, especially lac-tobacilli, influence the mutagenicity of in-testinal content and the levels of fecal mi-crobial enzymes. The some strain lacto-bacilli have been shown to significantly de-crease mutagenicity in healtly volunteersconsuming fried ground beef. They de-creased fecal E.coli levels in colon can-cer patients and reduced the fecal enzymes(Goldin et al., 1992; Ling et al., 1994;Morotomi, 1996).

Hosono et al. (1986a) were the first toreport that milks fermented with L.del-brueckii subsp. bulgaricus IFO 3533, L.lactis subsp. lactis IFO 12546 and En-terococcus faecalis IFO 12964 exhibitedantimutagenic activity against 4-nitro-quinoline-N-oxide (4NQO). Hosono et


al.(1986b) have also described the anti-mutagenic activity of milks fermentedwith Lactobacillus delbrueckii subsp.bul-garicus and Streptococcus thermo-philus again all the mutagens.

Nishioka et al. (1989) have reportedthat with respect to 49 strains of Lacto-bacillus three exhibited strong antimu-tagenic activity against 4NQO and 2-(2-furyl)-3-(5-nitro-2- furyl)acryl-amide (AF-2).

Hosoda et al. (1996) investigated theantimutagenic effect of milk fermented withL.acidophilus. They concluded that L.acidophilus decreased fecal mutagenic-ity in the human intestine.

For more information about antimu-tagenic properties of LAB, including lac-tobacilli see Hosono (1988, 1992), Rennerand Munzner (1991), Hosoda et al.(1992a,b, 1996), Thyagaraja et al. (1992),Thyagaraja and Hosono (1993, 1994),Aldelali et al. (1995), Hosanna et al. (1990,1997), Shah (2001), Wollowski et al.(2001).

HYPOCHOLESTEROLEMIC EFFECT

High-serum cholesterol levels are con-sidered to be a major risk factor for coro-nary heart disease, and also a factor in-ducing colon cancer in addition to high di-etary fat and low fiber (Pekkanen et al.,1990; Lichtenstein and Goldin, 1993; Lawet al., 1994). Several reports have indi-cated that serum cholesterol levels can bereduced by the consumption of certain cul-tured dairy products (Suzuki, 1995). In ad-dition, intestinal microflora has been im-plicated in influencing the serum choles-terol level. Germ-free animals on an el-evated cholesterol diet accumulate ap-proximately twice as much cholesterol inblood as do conventional animals on a simi-

lar diet (Eyssen, 1973). The latter excretemuch higher levels of cholesterol in thefeces than germ-free animals. This sug-gests that the intestinal microflora inter-fere with the cholesterol absorption fromthe intestines.

Several studies have suggested that lac-tobacilli and especially intestinal strains ofL. acidophilus have the potential of de-creasing serum cholesterol levels (Daniel-son et al., 1989; Walker and Gilliland, 1993;De Rodas et. al., 1996). However, not allstrains of L. acidophilus were active inthis regard (Gilliland et al., 1985; Lin etal., 1989). On the other hand L. acido-philus had the ability to assimilate choles-terol in in vitro studies, but only in the pres-ence of bile and under anaerobic condi-tions.

Gilliland et al. (1985) found that somestrains of L. acidophilus could removecholesterol from the laboratory mediumonly in the presence of bile and underanaerobic conditions. Because these con-ditions also occur in the intestine, theytested the manifestation of such an actionin vitro using young pigs and L. acido-philus strains of pig origin. The resultsshowed that the feeding of pigs with L.acidophilus possessing the ability to growin the presence of bile and to remove cho-lesterol from laboratory medium, signifi-cantly inhibited the increase in their se-rum cholesterol levels on a high choles-terol diet.

The lactobacilli are the primary con-tributors to bile salt hydrolase activity inthe ileum and cecum of the mouse (Tan-nock et al., 1989). If strains of Lactoba-cillu sssp.exhibiting a high degree of bilesalt hydrolase activity could be incorpo-rated into the intestinal tract, it is possiblethat the amount of deconjugation activityin the intestine could be increased.

S. A. Denev84

Some species of lactobacilli that arepresent in the intestinal tract candeconjugate taurocholic and glycocholicacids in anaerobic conditions Gilliland andSpeck (1977a). This deconjugation activ-ity is important because deconjugated bileacids do not function as well as conjugatedbile acids in the intestinal absorption of cho-lesterol (Eyssen, 1973). Increaseddeconjugation of bile acids could also re-sult in greater excretion of bile acids fromthe intestinal tract because free bile acidsare less likely to be reabsorbed in the in-testines (Chickai et al., 1987). Increasedexcretion of bile acids stimulates the syn-thesis of replacement bile acids from cho-lesterol, thus providing the potential to re-duce cholesterol levels in the body (Gilli-land, 1990). The synthesis of bile acids ishomeostatically regulated by the amountof bile acids returning to the liver (Dani-elsson and Sjovall, 1975). Also, cholesterolabsorption into the blood from the intes-tines is not supported as well by decon-jugated bile acids as it is by conjugatedbile acids.

According to Walker and Gilliland(1993) there is no correlation between biletolerance and cholesterol uptake ability ofthe L. acidophilus.They also have evalu-ated four strains of L. casei and observedconsiderable variation among strains intheir ability to assimilate cholesterol. Ad-ditionally they have shown that L.plantarum and bifidobacteria possess theability to assimilate cholesterol. Thus, itmay be possible to use other of intestinallactobacilli or related organisms in exert-ing beneficial influences on serum choles-terol levels. Additional research will berequired to confirm whether or not this isa possibility.

Imaizumi et al. (1992) found many straindifferences and that which microbial could

draw no clear conclusions on the generalmechanism activity within the gut mightregulate serum cholesterol levels.

Bile tolerance, the ability to deconjugatebile salts, and the ability to assimilate cho-lesterol are factors that may affect thepotential of some strains of L. acidophi-lus to help control human serum choles-terol concentration when used as dietaryadjuncts (Lys and Gilliland, 1994). Futureresearch is needed to determine themechanism of cholesterol uptake and todetermine whether or not the ingestion ofcells of a selected strains of lactobacilliand especially L. acidophilus could de-crease serum cholesterol levels in adult hu-mans with primary hypercholesterolemia.For more information about hypocholes-terolemic effect of LAB, including lacto-bacilli see Denev et al. (2000), Shah(2001), Lovegrove and Jackson (2003).

ANTICARCINOGENIC EFFECTS

Since the first observation by Bogdanovet al. (1962) that L. bulgaricus producedsubstances, which were active against tu-mor development there, have been a num-ber of reports in the same vein. Duringthe last two decades, several experimentsand reviews indicating that LAB play asignificant role in suppressing carcinogen-esis have been published (Sandine, 1979;Friend et al., 19S2; Reddy et al., 1983;Deeth, 1984; Friend and Shahani, 1984a;Gurr, 1987; Fernandes et al., 1987, 1988;Hosono, 1988a; Kanbe, 1988; Gilliland,1989; Wada and Hayakawa, 1990;Guilliams, 1999; Wollowski et al., 2001;Mercenier et al., 2002).

Epidemiological evidence and dietarystudies have shown that consumption ofdairy products fermented by lactobacillimay reduce the risk of colon cancer in both


animals and humans. Numerous studieshave suggested that intestinal and otherlactobacilli possess anticarcinogenic activ-ity (Mitsuoka, 1981; Goldin and Gorbach,1980, 1983; Shahani et al., 1983; Friendand Shahani, 1984; Shimizu et al., 1987;Fernandes and Shahani, 1990; Adachi,1992; Salminen, 1996).

Parenteral administration of somestrains lactobacilli, especially Lactobacil-lus casei Shirota strain has had antitumorand immunostimulating activities on experi-mentally implanted tumors (Morotomi,1996; Miguel, 2001). Similar effects havebeen verified by oral administration. In arecent study Lactobacillus GG wasshown to cause a dramatic reduction inDMH induced tumor formation in rats. Itwas reported that Lactobacillus GG in-hibited the initiation and early phase pro-motion on the tumorigenesis process(Goldin et al., 1996). However, it was re-ported that the organism was not able toprevent the growth of tumors once theyhad been established (Goldin et al., 1996).The fact that Lactobacillus GG is an or-ganism of human origin capable of sur-viving in the GT and that it inhibits tumorinitiation or early promotion in the colonprovides a basis for further studies of thesefactors in humans. In a similar manner, L.casei Shirota strain has been shown tohave inhibitory properties on chemicallyinduced tumors in animals (Kato et al.,1994; Morotomi, 1996). In a clinical study,prophylactic effects of oral administrationof L. casei Shirota strain on initiation orearly promotion in the colon provides abasis for further studies of these factorsin humans. In a similar manner, L. caseiShirota strain has been shown to have in-hibitory properties on chemically inducedtumors in animals (Kato et al., 1994;Morotomi, 1996). In a clinical study, pro-

phylactic effects of oral administration ofL. casei Shirota strain on the recurrenceof superficial bladder cancer has been re-ported in two Japanese studies (Aso andAkazan, 1992; Aso et al, 1995). LAB hasalso been indicated in colonic fermenta-tion producing butyrate or butyric acid inthe colon. This alteration in intestinal me-tabolism may be due to changes in theintestinal microecology following probioticintake or the direct metabolism of slowlyabsorbable components by orally adminis-tered colonizing LAB (Salminen et al.,1996). Butyrate has been shown in vitrostudies to slow the growth of cultured co-lon cancer cells. Young (1996) has pro-posed that butyrate may be a diet-regu-lated, natural antitumor compounds at leastpartly responsible for the antitumor effectof dietary components and also dietaryprobiotics. When these studies are relatedto animal data on several Lactobacillusstrains and colon cancer related param-eters, it is important to assess the poten-tial of probiotic lactobacilli for cancerchemoprevention (Salminen, 1996;Wollowski et al., 2001).

Since intestinal microorganisms havebeen postulated to play an important rolein conversion of chemical procarcinogensto carcinogens in the gut, the activity ofcertain fecal enzymes (azoreductase,nitroreductase, β-Glucuronidase β-Glu-cosidase and etc.) has been used to moni-tor colon carcinogenesis (Golden and Gor-bach, 1976; Wollowski et al., 2001).

β-Glucuronidase plays a role in the gen-eration of carcinogenic aglycones, such as3-hydroxybenzopyrene from 3-hydro-xybenzopyrene-p-glucuronide (Kinoshitaand Gelboin, 1978) in colon, from glucu-ronides formed in the liver. Nitroreductaseand azoreductase are related to the for-mation of aromatic amines which can be

S. A. Denev86

converted to nitroso- and N-hydro-xycompounds in many tissues. These prod-ucts are known carcinogens (Cerniglia etal., 1982; Manning et al., 1985). Steroid-7-dehydroxylase is responsible for theformation of lithocholic acid from cheno-deoxycholic acid which is primary bile acidformed from cholesterol in the liver. Li-thocholic acid, a secondary bile acidformed by the bacterial enzyme in the co-lon, is a co- carcinogenic substance (Carey,1973).

Experiments performed in animal andhuman models showed that some lactoba-cilli could decrease the levels of enzymesazoreductase, nitroreductase, β-Glucu-ronidase and β−Glucosidase, responsiblefor activation of some procarcinogens, anddecrease the risk or the speed of tumor

development (Goldin and Gorbach, 1992).The results of some studies are shown inTable 5.

Several investigations have shown aninfluence of the intake of LAB and espe-cially Lactobacillus ssp. fermented-milkproducts on the gut flora, enzyme activi-ties and colon carcinogenesis (Wollowskiet al., 2001). According to Friend andShahani (1984) the lactobacilli inhibit car-cinogenesis by (a) inactivating or inhibit-ing formation of carcinogenic compoundsin the gastrointestinal tract; and (b) sup-pressing promotion of cancer throughstimulation or enhancement of the immuneproperties of the host. Fernandes andShahani (1990) observed that LAB, includ-ing lactobacilli, inhibits carcinogenesis by(a) prevention of cancer initiation by means


β β

Table 5

Species

Azo

redu

ctas

e

Nitr

ored

ucta

se

-G

lucu

roni

dase

-G

luco

sida

se

Reference

L. acidophilus d* d d Goldin and Gorbach (1977, 1984) L. acidophilus d d Goldin et al. (1980) L. acidophilus d d Auebo et al (1980) L. acidophilus d d Pedrosa et al. (1990) L. acidophilus d Marteau et al. (1990) L. acidophilus d Lidbeck et al. (1991) L. acidophilus d Bouhnik et al. (1996) L. acidophilus (NCFM) d d Cole et al. (1989) L. casei strain GG d Goldin et al. (1992) L acidophilus d L. reuteri d L. casei Shirota d Spanhaak et al. (1998) L. johnsonii d Haberer et al. (1995) L rhamnosus GG d d Ling et al. (1994)(d)* Decrease

Effect of Lactobacilli on fecal bacterial enzymes

87

of direct and indirect reduction of pro-car-cinogens and (b) suppression of initiatedcancer.

Another possible explanation for thepreventive effect of lactobacilli on carcino-genesis is their effect on other bacteria inthe intestine. Lactobacilli might suppressthe growth of bacteria that convertprocarcinogens into carcinogens, therebyreducing the amount of carcinogens in theintestine. The activity of the enzymes thatconvert procarcinogens into carcinogensis often used as an indicator of the effectof probiotics on the intestinal microflora(Roos and Katan, 2000).

The mechanism of anticarcinogenic ac-tion has not yet been fully elucidated. Sev-eral studies have suggested that anti-car-cinogenic activity of Lactobacillus spp.may be attributed to:

• Activation of the host’s immune system toantitumourigenesis (McIntosh, 1996);

• Improvement (quantitatively/qualitatively) ofthe intestinal microflora, reducing the putative pro-ducers of carcinogens and cancer promoters (im-provement of the intestinal microecology: e.g. morebile-acid degrading bacteria; less bacteria produc-ing the enzymes azoreductase, nitroreduc-tase,beta-glucuronidase, beta-glucosidase, etc.(Mercenier et al., 2002);

• Production of compounds that inhibit theproliferation of tumor cells (Reddy et al., 1973);

• Antagonistic action against the organismsthat convert procarcinogens to carcinogens by en-zyme activity (Auebo et al., 1980; McIntosh, 1996;Roos and Katan, 2000);

• Bind to mutagenic compounds in the intes-tine and decreasing the absorbtion of these mu-tagens (Orrhage et al., 1994; Young, 1996;Guilliams, 1999; Roos and Katan, 2000);

• Direct supprecion of the carcinogens and/orprocarcinogens by binding, blocking, remowing(McIntosh, 1996);

• Degradation of the carcinogens formed

(Rowland and Grasso, 1975);• Alteration of colonic motility and transit

time (McIntosh, 1996).

During the last five years an impresiveand useful reviews in the field of anti-car-cinogenic properties of lactobacilli are pro-vided by Wollowski et al. (2001); Herichet al. (2002); Norat and Riboli (2003); Gilland Rowland (2003).

IMMUNE SYSTEM STIMULATION

The immune system consist of a num-ber of organs and several different celltypes that recognize accurately and spe-cifically foreign antigens on microorgan-isms and thereby, eliminate those organ-isms. The organs of the immune systemare bone marrow, thymus, spleen, Peyer’spatches, and lymph nodes. The cells of thissystem are the leukocytes, or white bloodcells. There are two categories of leuko-cytes; 1) phagocytes, including neutrophils,monocytes, and macrophages, which formpart of the innate immune system and pro-vide nonspecific immunity, and 2) the lym-phocytes, which mediate adaptive, or spe-cific immunity. The specific immune re-sponse can produce cellular immunitymediated by specifically sensitive immunecells and the humoral immune responsemediated by the antibody production(Perdigon et al., 1995; Cebra, 1999).

A large proportion of the immune cellsof the body are associated with the gut. Inthe healthy host, the presence of themicrobiota is tolerated by the immune sys-tem, although the mechanisms involved arenot precisely known. Nevertheless, it canbe inferred that tolerance toward themicrobiota exists, because human patientswith inflammatory bowel diseases and ex-perimental animals with dysfunctional im-

S. A. Denev88

mune systems suffer from chronic, im-mune-mediated inflammation of the bowelmucosa (Podolsky, 2002). Much evidencepoints to the presence of the microbiota asthe fuel for this smoldering inflammation.The autochthonous microbe-immune sys-tem relationship in healthy animals musttherefore be one of tolerance and requiresmechanistic investigation. The allochtho-nous microbe-immune system relationshipis presumably quite different, at least ini-tially, because the immune system will ex-perience novel antigenic complexes witheach encounter with a different bacterialstrain. Continuous close encounters withthe same strain, either serendipitous (foodmicrobiota) or intentional (probiotic), could,one supposes, eventually engender toler-ance (Tannock, 2004).

The gut microflora is an important con-stituent in the intestine’s defense barrier,as shown by increased antigen transportacross the gut mucosa in the absence ofan intestinal microflora. This notion fur-ther supported by a demonstration that thegut microflora elicit specific immune re-sponses at a local and a systemic level(Kailua et al., 1992; Isolauri et al., 2001;Perdigon et al., 2001). It has been hypoth-esized that LAB may have some potentialrole in augmenting the immune system ofthe host (Turjman et al., 1982). This hy-pothesis was proposed on the observationthat LAB suppressed peritoneally and sub-cutaneously implanted tumors in mice inshort-term studies. LAB did not directlysuppress the tumor, but the suppressionappeared to be mediated indirectly throughthe host’s immune system.

The effects of LAB on the immune sys-tem could have theoretical applications fortumor suppression, and anti-infective ac-tivity. None of these potential effects hasbeen in man, and LAB do not yet have

a place among human cancer therapies(Marteau and Rambaud, 1993). However,very active and interesting research is de-veloping in this field.

During the past ten years, interactionsbetween lactobacilli and immunocompe-tence have been studied extensively invitro and in vivo. These investigationshave revealed that lactobacilli not only con-stitute an integral part of the healthy gas-trointestinal microecology, but are also in-volved in the host’s protective mechanismsby increasing its specific and non-specificimmune mechanisms (Renner, 1995). Theintestinal microflora has a profound influ-ence on the immunological state of thehost. Live indigenous bacteria or their an-tigens can, in fact, penetrate the epithelialbarrier of the intestine and directly stimu-late the immunocompetent cells. Thegerms present in the intestinal lumen fa-vour the production of suppressor cells, thelymphocytic differentiation or even the“helper” cell activity.

The intestinal lactobacilli can stimulatethe immune system in two ways. They caneither migrate thought the gut wall as vi-able cells and multiply to a limited extentor antigens released by the dead organ-isms can be absorbed and stimulate theimmune system directly. A third school ofthought suggests that the lactobacilli areacting indirectly through an effect on theother components of the gut flora. It is aproduct of this change that induces theimmune response. At present, which ofthese methods is, being used is not cer-tain, but there appears to be some rela-tionship between the ability of a strain totranslocate and the ability to be immuno-genic.

The improved immunity induced by lac-tobacilli may be manifested in three ways:

• Increased macrophage activity shown by the


enhanced ability to phagocytose microorganismsor carbon particle;

• Increased production of systemic antibodyusually of the immunoglobulin classes IgG, IgMand interferon;

• Increased local antibody at mucosal surfacessuch as the gut wall. These are usually IgA.

The first (and possibly the only) con-tact of lactobacilli with the immune sys-tem occurs in the gut-associated lymphoidtissue. Perdigon et al. (1990) showed thatoral administration of L. casei, L. acido-philus, L. bulgaricus and S. thermophi-lus increased the levels of immunoglo-bulins in the intestinal fluid. However, onlyL. casei pretreated mice had increased se-cretion of specific antibodies against Sal-monellae when challenged with Salmonel-lae. De Simone et al. (1987a, 1988) re-ported that yogurt or heated yogurt admin-istered to mice increased the percentageof B-lymphocytes in the Peyer’s patches,and the proliferative responses of thesecells to stimulants. When those mice chal-lenged with Salmonellae, antibacterial ac-tivity of the Peyer’s patche lymphocytesand thus resistance to infection was in-creased by living yogurt.

A large number of experiments havedemonstrated that LAB, especially lacto-bacilli could exert immunostimulatory ef-fects (Adachi, 1992; Tomioka and Saito,1992; Malin et. al., 1996; Perdigon et al.,1999, 2001; Koop-Hoolihan, 2001) and en-hance host resistance against experimen-tal infections (Perdigon and Alvarez, 1992).The effects seem mainly due to the acti-vation of the macrophages and non-spe-cific immunity by cell wall components ofthe lactobacilli (Kato et al., 1984; Sato,1984; Yokokura et al., 1986; Sato et al.,1988a, 1988b; Ohashi et al., 1989; Moineauand Goulet, 1991; Miettinen et al., 1996;

Fuller and Perdigon, 2000; Perdigon et al.,2001).

The non-specific defence mechanismsof the host include phagocytosis, which iseffected by macrophages, polymorpho-nuclear leucocytes, histiocytes and mono-cytic cells that are part of the mononuclearphagocytic system, which removes foreignantigens.In this system, the most impor-tant cells are macrophages. The state ofactivation of these is a measure of the non-specific immune response of the host(Perdigon and Alvarez, 1992)

Changes in monocytes’ and lympho-cytes’ activities, a measure of cell-medi-ated immunity, have also been studiedfollowing short-therm feeding of viableLAB and yogurt to mice. Mice were fedviable L. acidophilus, L. casei subsp.casei, L. delbrueckii subsp. bulgaricusand S. thermophilus, and changes inmacrophage enzymes and in vivo phago-cytic function of reticuloendothelial sys-tem were measured (Perdigon et al.,1986a). Feeding of L acidophilus and L.casei subsp. casei increased all three en-zymatic activities (Perdigon et al., 1986b,1987). The feeding of L delbrueckiisubsp. bulgaricus also increased β-glu-curonidase and β -galactosidase activities.(Perdigon et al., 1986a, 1987).

The effect of lactobacilli on the cellu-lar and the humoral immune response hasbeen investigated by Perdigon et al.(1986c,1988a, b). They found that the oral ad-ministration of L. casei, L. acidophilusand L. delbrueckii subsp. bulgaricusenhanced both the cellular and the humoralimmune response. L. casei and L. acido-philus were tested singly and together byPerdigon (1986b) for stimulation of phago-cytic activity. It was found that the mix-ture was more effective than the strainsgiven singly. These suggest that a mixture

S. A. Denev90

of lactobacilli was more effective and theindividual effects of the component strainsmay be additive.

In feeding experiments with micewhere 1.2 x 109 cells of LAB per daywere administered, the following resultswere obtained (Perdigon et al., 1993): Lacidophilus increased IgA productiononly temporarily, but increased IgG pro-duction thoughout the feeding period.; L.casei enhanced the proliferation of IgA-producing cells; yoghurt feeding increasedthe number of plasma cells, lymphocytesand macrophages. L. casei feeding givento mal-nourished animals slightly increasedthe number of circulating leukocytes andthe phagocytic activity of peritoneal mac-rophages. This feeding also restored thestrict anaerobic population in the small in-testine, but failed to prevent bacterialtranslocation. L. casei induced an increasein the number of IgA-producing cells aswell as the level of IgM (Perdigon et al.,1995). The above results suggested that:(a) L. casei,L. acidophilus, L. del-brueckii subsp. bulgaricus and certaindoses of S. thermophilus are capable ofactivating the cells involved in the non-spe-cific immune response; (b) the LAB ca-pable of survival and growth in the intesti-nal tract, such as L. casei and L. acido-philus, are more efficient in the activa-tion.

De Simone et al (1986, 1987b) showedthat several LAB including yogurt bacte-ria stimulated in vitro production of inter-feron-g (IFN-g) by human blood lympho-cytes. Several in vivo studies in manshowed then that ingested yogurt bacteriaat last in very large doses (1011 and 3x1012

day-1) stimulated IFN-g production (DeSimone et al., 1991; SoIis and Lemonnier,1991). Kishi et al. (1996) observed that L.brevis subsp.coagulans significantly in-

creased a-interferon production. A ben-eficial consequence of interferon stimula-tion could be an increase in resistance tosome infections. However, interferon canexert both beneficial and detrimental ef-fects to man (Murray, 1988). More ex-periments, including dose-response stud-ies, and trials with clinical end-points areneeded.

Perdigon et al. (1993) present the fol-lowing hypothesis for the immunomodu-lating effects of LAB: not all lactobacilliinduce synthesis of IgA; for those that do,the dose administered plays a critical role;the first effect of lactobacilli on the im-mune system occurs at the local level onthe gut-associated lymphoreticular tissue,which may or may not send signals thatwould permit the activation of the immunesystem in general. Many other studieshave shown that oral administration of lac-tobacilli could influence parameters of thesystemic immunity (Morissete et al., 1991;Perdigon and Alvarez, 1992; Marteau,1995; Sotirov et al., 2000, 2001; Isolauri etal., 2001). Although many of these resultswere obtained using mice as experimen-tal models, they are not easily transferredto human beings. For the use of lactoba-cilli as immunomodulatory agents, experi-mental models are absolutely necessaryto determine that effects of lactobacilli onthe host are innocuous and to select thosebacteria that most effectively enhance theimmune response. However, the exploita-tion of that knowledge for therapeutic pur-poses is still limited (Perdigon et al., 1995).For more information about immunologiceffects of lactobacilli see Guilliams (1999),Matsuzaki and Chin (2000), Isolauri et al.(2001); Perdigon et al. (2001); Kaur et al.(2002).

Lactobacilli clearly offer microbiolo-gists exciting research prospects, both for


biomedical applications and for acquiringfundamental knowledge of how bacterialcells function in the gut ecosystem. Asmodel gut bacteria, they may provide les-sons in the molecular mechanisms that de-fine autochthony as well as in understand-ing bacterial physiology in relation to hostwelfare. For these reasons, lactobacilli areset to remain the fond favorites of manymicrobiologists.

AcknowledgementsThis work was supported by Post-Doctoral

Research Fellowship Grant from the Japan Inter-national Science & Technology Exchange Center,Japan, and EU Grant (University of Groningen),The Netherlands. The financial assistance is highlyappreciated. The author is indebted to all partnersof the Research Project “Role of Lactobacilli inGastrointestinal Ecosystem” for the excellent work-ing conditions were provided. Gratitude is ex-pressed to I. Suzuki, H. Kimoto, H. Nakai, and W.Konnings, for their research support and collabo-ration. The contributions of many universities, labo-ratories and investigators who provided publica-tions are gratefully acknowledged. The authorwould like to thank many colleagues who kindlysupplied published information for this manuscript:R. Fuller, G. Tannock, T. R. Klaenhammer, S. E.Gilliland, D.S. Savage, T. Mitsuoka, A. Hosono,G. Perdigon, C. F. Fernandes, K. M. Shahani, E.Nurmi, P. G. Sara, W. E. Sandine, F. Edens, and etc.

ReferencesAdachi, S, 1992. Lactic Acid Bacteria and the

Control of Tumors.In: The Lactic Acid Bacte-ria Vol.1. The Lactic Acid Bacteria in Healthand Disease (Ed. Wood, J.B.) Elsevier AppliedScience, London and New York., pp.233-261.

Adams, M. R., and C. J. Hall, 1988. Growth in-hibition of food-borne pathogens by lactic andacetic acids and their mixtures. Int. J. Food Sci.Technol., 23:287-290.

Ahrne, S., S. Nobaek, B. Jeppsson, I. Adlerberth,

A. E. Wold and G. Molin, 1998. The normalLactobacillus flora of healthy human rectal andoral mucosa. J. Appl. Microbiol. 85:88-94.

Aries, V., B. S. Crowther, B. S. Drasar, and M.J. Hill, 1969. Degradation of bile salts by hu-man intestinal bacteria. Gut, 10: 575-576.

Aries, V. and M. J. Hill, 1970. Degradation ofsteroids by intestinal bacteria. Decon-jugationof bile salts. Acta Biochem. Biophys. 202:526.

Arihara, K., H. Ota, M. Itoh, Y. Kondo, T.Sameshima, H. Yamanaka, M. Akimoto, S.Kanai, T. Miki, 1996. Application of intesti-nal Lactobacilli to meat fermentation. Fifth Sym-posium on Lactic Acid Bacteria, Genetics, Me-tabolism and Applications (Abstracts),Veldhoven, The Netherlands, September 8/12,J1.

Aso, Y. and H. Akazan, 1992. Prophylactic effectof a Lactobacillus casei preparation on the re-currence of superficial bladder cancer. Urol. Int.49:125-129.

Aso, Y., H. Akazan, T. Kotake, T. Tsukamoto,K. Imai, and S. Nafto, 1995.Preventive effectof a Lactobacillus casei preparation on the re-currence of superficial bladder cancer in adouble- blind trial. Eur. Urol. 27:104-109.

Axelsson, L.T. and S. Lindgren, 1987. Charac-terization and DNA homology of Lactobacil-lus strains isolated from the pig intestine. J.Appl. Bacteriol. 62:433- 40.

Axelsson, L. T., T. C. Chung, W. J. Dobrogosz,and S. Lindgren, 1989. Production of a broad-spectrum antimicrobial substance by Lactoba-cillus reuteri. Microb. Ecol. Health Dis., 2:131-136.

Ayebo, A. D., I. A. Angelo, and K. M. Shahani,1980. Effect of ingesting Lactobacillus acido-philus milk upon fecal flora and the enzymeactivity in humans, Milchwissen-schaft, 35:730-733.

Aymerich, M.T., M. Garriga, J. M. Monfort, I.Nes, and M. Hugas, 2000. Bacteriocin-pro-ducing lactobacilli in Spanish-style fermentedsausages: characterization of bacteriocins. FoodMicrobiol. 17:33-45.

Baele, M., L., A. Devriese, and F. Haesen-brouck, 2001. Lactobacillus agilis is an im-portant component of the pigeon crop flora. J.

S. A. Denev92

Appl. Microbiol. 91:488-491.Bailey, J. S., 1988. Integrated colonization con-

trol of Salmonella in poultry. Poultry Sci.67:928-932.

Barefoot, S.F., and T. R. Klaenhammer, 1983.Detection and activity of Lactacin B, a bacte-riocin produced by Lactobacillus acidophilus,Appl. Environ. Microbiol., 45:1808-1815.

Barefoot, S. F., and T. R. Klaenhammer, 1984.Purification and characterization of the Lacto-bacillus acidophilus bacteriocin lactacin B,Antimicrob. Agents Chemother. 26:328-334.

Barrow, P. A., B. K. Brooker, R. Fuller, and M.J.Newport, 1980.The attachment of bacteria tothe gastric epithelium of the pig and its impor-tance in the microecology of the intestine.J.Appl. Bacteriol. 48:147-54.

Bengmark, S., 1998. Ecological control of the gas-trointestinal tract. The role of probiotic flora.Gut, 42:2-7.

Bernet, M.F., D. Brassart, J. R. Neeser, A. L.Servin, 1994. Lactobacillus acidophilus LA1binds to cultured human intestinal cell lines andinhibits cell attachment cell invasion byenterovirulent bacteria. Gut,, 35:483-489.

Bianchi-Salvadori, B., 1986. Intestinal microf-lora: the role of yogurt in the equilibrium of thegut ecosystem, Int. J. Immunotherapy, 2:9-18.

Binder, H. J., B. Filborn, and M. Flock, 1975.Bile acid inhibition of intestinal anaerobic or-ganisms. Am. J. Clin. Nutr., 28:119-124.

Bird, A. R., I. L. Brown and D. L. Topping, 2000.Current issues in Intestinal Microbiology, 1:25-37.

Bird, A. R., W. J. Croom and B. W. Bride, 2002.Dietary Management of the IntestinalMicrobiota Using Probiotics and Prebiotics inHumans and Animals. Proceedings of Austra-lian Poultry Science Symposium, Universityof Sydney, NSW, Feb. 11th-13th , Australia, pp1-5.

Boever, P. De, and W. Verstraete, 1999. Bile saltdeconjugation by Lactobacillus plantarum 80and its implication for bacterial toxicity. J. Appl.Microbiol. 87: 345-352.

Bogdanov, I. G., P. Popkhristov and L. Marinov,1962. Anticancer effect of antibioticumbulgaricum on Sarcoma-180 and the solid form

of Ehrlich carcinoma.Abstr. VIII Int. CancerCongress, Moscow, pp. 364-365.

Bogdanov, I. G., P. G. Dalev, L. A. Gurevich, M.N. Kolosov, V. P. Malkova, L. A.Plemyannikova and I. B. Sorokina, 1975.Antitumour glycopeptides from Lactobacillusbulgaricus cell wall. FEBS Letters, 57:259-261.

Boris, S., R. Jimenes-Diaz, J.L. Caso, and C.Barbes, 2001.Partial characterization of a bac-teriocin produced by Lactobacillus delbrueckiisubsp.lactis UO004, an intestinal isolate withprobiotic potential. J. Appl. Microbiol. 91:328-333.

Bouhnik Y., B. Flourie, C. Andrieux, N. Bisetti,F. Briet, and J. C. Rambaund, 1996. Effectsof Bifidobacterium sp. fermented milk ingestedwithout inulin on colonic bifi-dobacteria andenzymatic activities in heal-thly humans. Eur.J. Clin. Nutr. 50:269-273.

Brooker, B., and R. Fuller, 1975. Adhesion oflactobacilli to the chicken crop epithelium. J.Ultrastr.Res. 52: 21-31.

Browmik, T., M. C. Johnson, and S. Ray, 1985.Isolation and partial characterization of the sur-face protein of Lactobacillus strains. Int. J.Food Microbiol. 2:311-16.

Brown, J. P., 1981. Reduction of polymeric azoand nitro dyes by intestinal bacteria. Appl.Environ. Microbiol. 42:1283-1285.

Brownlee, A., and W. Moss, 1961. The influenceof diet on lactobacilli in the stomach of the rat.J. Pathol. Bacteriol. 82:513-16.

Bruce, W. R., A. J. Varghese, R. Furrer, and C.P. Land, 1977.A mutagen in the feces of nor-mal humans. In: Origjns of Human Cancer(Eds. Hiatt, H.H. & Watson, J.D.), Cold SpringHarbor Laboratory, Cold Spring Harbor, NY,pp.1641.

Carey, J. B. Jr.,1973. Bile salt metabolism in man.In: The Bile Acids, Vol 2, (Eds. Nair, P.P. &Kritchevsky, D.), Plenum Press, New York,pp. 62.

Cebra, J. J., 1999. Influences of microbiota onintestinal immune system development.Am.J.Clin Nutr. 69 (suppl):1046S-1051S.

Cenatiempo, Y., J. M. Serjeaud, F. Sfet, C.Fremaux, Y. Hechard, and D. Robfchon,1990. Bacteriocins of lactic acid bacteria: re-


cent data on their structure, their mode of ac-tion and their genetic determinants. Lait 76(1/2):169-177.

Cerniglia, C. E., J. P. Freeman, W. Franklin,and L. D. Paek, 1982. Metabolism of azo dyesderived from benzidine 3,3’-dimethyl benzi-dine and 3,3' -dimethoxybenzidine to poten-tially carcinogenic aromatic amines by intesti-nal bacteria. Carcinogenesis 3:1255-1259.

Charteris, W. P., P. M. Kelly, L. Morelli, and J.K. Collins, 1998. Development and applica-tion of an in vitro methodology to determinethe transit tolerance of potential probiotic Lac-tobacillus and Bifidobacterium species in theupper human gastrointestinal tract. J. Appl.Microbiol. 84:759-768.

Chickai, T., H. Nakao, and K. Uchida, 1987.Deconjugation of bile acids by human intesti-nal bacteria implanted in germ-free rats. Lip-ids, 22:669-674.

Chin, H. S., J. S. Shim, J. M. Kim, R. Yang,and S.S.Yoon, 2001.Detection and antibacte-rial activity of a bacteriocin produced by Lac-tobacillus plantarum. Food Sci. and Biotechnol.,10 (4):335-341.

Christiaens, H., R. J. Leer, P. H. Pouwels, andW. Verstraete, 1992. Cloning and expressionof a conjugated bile acid hydrolase gene fromLactobacillus plantarum by sing a direct plateassay. Appl. Environ. Microbiol., 58:3792-3798.

Chung, T. C., L. Axelsson, S. E. Lindgren, andW.J. Dobrogosz, 1989. In vitro studies onreuterin synthesis by Lactobacillus reuteri.Microb. Ecol. Health Dis. 2: 137-144.

Coconnier, M. H., T. R. Klaenhammer, S.Kerneis, M. F. Bernet, and A. L. Servln,1992. Protein mediated adhesion of Lactoba-cillus acidophilus BF 2 FO4 on humanenterocyte and mucus-secreting cell lines inculture. Appl. Environ. Microbiol., 58:2034-2039.

Coconnier, M.-H., V. Liévin, M. F. Bernet-Camard, S. Hudault, and A. L. Servin, 1997.Antibacterial effect of the adhering human Lac-tobacillus acidophilus strain LB. Anti-microb.Agents Chemother. 41: 1046-1052.

Coconnier, M. H., V. Lieven, E. Hemery, and A.

L. Servin, 1998. Antagonistic activity againstHelicobacter infection in vitro and in vivo bythe human Lactobacillus acidophilus strain LB.Appl.Environ. Microbiol,. 64: 4573-4580.

Cole, C. B., R. Fuller, and S. M. Carter, 1989.Effect of probiotic supplements of Lactobacil-lus acidophilus and Bifidobacteriumadolescentis 2204 on â-glucosidase and â-glu-curonidase activity in the lower gut of rats as-sociated with a human faecal flora. MicrobialEcol. in Health and Diseases 2: 223-225.

Cole, D. J. A., W. H. Close, P. H. Brooks and B.Hardy, 2003. Time for a new look at pro-biosisas a way of managing the gut microflora of thepig. Animal Talk, vol.10 (1):1-2

Coleman, J. P. and L. L. Hudson, 1995. Cloningand characterization of a conjugated bile acidshydrolase gene from Clostridium perfringens.Appl. Environ. Microbiol. 61:2514-2520.

Condon, S., 1987. Responses of lactic acid bacte-ria to oxygen. FEMS Microbiol. Rev. 46:269-280.

Conway, P. L., S. L. Gorbach, and B.R. Goldin,1987. Survival of lactic acid bacteria in the hu-man stomach and adhesion to intestinal cells. J.Dairy Sci., 70:1-12.

Conway, P. L., 1989. Lactobacilli: fact and fiction.In: The Regulatory and Protective Role of theNormal Microflora (Eds. R. Grubb, T.Midtvedt and E. Noris), M. Stockton Press,Stockho1m, pp. 263- 83.

Conway, P. L. and S. Kgelleberg, 1989. Protein-mediated adhesion of Lactobacillus fermentumstrain 737 to mouse stomach squamous epi-thelium. J. Gen. Microbiol., 135:1175-86.

Correa, P., C. Cuello, and K. Duque, 1970. Car-cinoma and intestinal metaplacia of the stom-ach in Columbian emigrants. J. Natl. CancerInst., 44:297-300.

Corrier, D. E., A. G. Nisbet, A. G. Hollister, R.C. Beier, C. M. Scanlan, B. M. Hargis, andJ. R. DeLoach, 1994. Resistance against Sal-monella enteritidis cecal colonization in Leg-horn chicks by vent lip application of cecalbacterial culture. Poultry Sci., 73:648-652.

Corrier, D. E., A. G. Nisbet, C. M. Scanlan, A.G. Hollister, and J. R. DeLoach, 1995a. Con-trol of Salmonella typhimurium colonization in

S. A. Denev94

broiler chicks with a continuous flow charac-terized mixed culture of cecal bacteria. PoultrySci., 74: 916-924.

Corrier, D. E., A. G. Nisbet, C. M. Scanlan,A.G. Hollister, D. J. Caldwell, L. A. Tho-mas, B. M. Hargis, T. Tomkins and J. R.DeLoach, 1995b. Treatment of commercialbroiler chickens with a characterized culture ofcecal bacteria to reduce Salmonella coloniza-tion Poultry Sci. 74: 1093-1101.

Daeschel, M. A., 1989. Antibacterial substancesfrom lactic acid bacteria for use as food preser-vatives. Food Technol., 43(1): 164-167.

Daeschel, M. A., M.S. Mckenney and L. C.McDonald, 1990. Bactericidal activity of Lac-tobacillus plantarum C11. Food Microbiol.,7:91-98.

Danielsson, A. D., K. R. Peo, K. M. Shahani, A.J. Lewis, P.J. Whalen, and M. A. Amer, 1989.Anticholesteremic property of Lactobacillusacidophilus yogurt fed to mature boards. J.Anim. Sci., 67: 966-970.

Danielsson, H., and J. Sjovall, 1975. Bile acidsmetabolism. Ann. Rev. Biochem., 44: 233- 240.

De Boever, P., and W. Verstraete, 1999. Bile saltdeconjugation by Lactobacillus plantarum 80and its implication for bacterial toxicity. J. Appl.Microbiol., 87:345-352.

Deeth, H. C., 1984. Yogurt and cultured products.Austr. J. Dairy Technol,. 39:111-113.

De Kairuz, M. S., M. E. Olazabal, G. Oliver,A.P. De Ruiz Olgado, and R. N. Farias, 1988.Fatty acid dependent hydrogen peroxide pro-duction in Lactobacillus. Biochem. Biophys. Res.Commun., 152:113-121.

De Klerk, H. C., and J. N. Coetzee, 1961. Anti-biosis among lactobacilli, Nature, 192:340-341.

Denev, S., 1993. Probiotics in lambs nutrition. In:Meeting on sheep and goat nutrition (A.NastisEd.), 24-26 Sept. Aristotle Univ., Tsessaloniki,Grece, Abstracts, pp.87.

Denev, S., 1993a. Effects of treatment of lambswith probiotic, containing lactic acid bacteria.In: Meeting on sheep and goat nutrition(A.Nastis Ed.), 24-26 Sept. Aristotle Univ.,Tsessaloniki, Grece, Abstracts, pp.231.

Denev, S., 1996. Probiotics, Past, Present andFuture. Bulg. J. Agric. Sci. 2: 445-474.

Denev, S., 1997. Probiotics-Present and Future.Proceedings of the First Alltech’s ResearchSeminar “Biotechnology in the Feed Industry”(S. Denev Ed.), 5th March, Sofia, Bulgaria, pp.67-78.

Denev, S., I. Suzuki, and H. Kimoto, 2000. Roleof Lactobacilli in Human and Animal Health.Animal Sci. J. (Jp), vol. 71(6): 549-562.

De Rodas, B. Z., S. K. Gilliland, and C. V. Max-well, 1996. Hypocholesterolemic action of Lac-tobacillus acidophilus ATCC 43121 and cal-cium in swine with hypercholesterolemia in-duced by diet. J. Dairy Sci., 79: 2121-2128.

De Simone, C., B. Bianchi-Salvadory, R. Ne-gri, M. Ferrazzi, L. Baldinelli, and R. Vesely,1986. The adjuvant effect of yogurt on pro-duction of gamma-interferon by con A-stimu-lated human peripheral blood lymphocytes.Nutr. Rep. Int., 33: 419-433.

De Simone, C., R. Vesely, R. Negri, B. Bianchi-Salvadory, S. Tzantzoglou, A. Cilli, andL.Lucci, 1987a. Enhancement of immune re-sponse of murine Peyer’s patches by dietsupplemented with yogurt. Immunophar-macol. Immunotoxicol. 9:87-100.

De Simone, C., M. Ferrazzi, M. Di Seri, F.Momgio, L. Baldinelli, and S. Di Fabio,1987b. The immunoregulation of the intestinalflora bifidobacteria and lactobacilli modulate theproduction of (IFN-g) induced by pathogenicbacteria. Int. J. Immunother. 3:151-158

De Simone, C., S. Tzantzoglou, L. Baldinelli,S. Di Fabio, B. Bianchi-Salvadory, K. Jirillo,and R. Vesely, 1988. Enhancement of host re-sistance against Salmonella typhymurium in-fection by diet supplemented with yogurt.Immunopharmacol. Immunotoxicol. 10:399-415.

De Simone, C., E. Rosati, S. Moretti, B.Bfanchi-Salvadory, R.Vesely, and K. Jirillo,1991.Probiotics and stimulation of the immuneresponse. Eur. J. Clin. Nutr., 45:32-34.

Desmazeaud, M., 1994. Bacteriocins of lactic acidbacteria and use in dairy industry. Rev. de Med.Vet. 10: 711-720.

DeVuyst, L., and K. J. Vandamme, 1994.Bacteriocins of Lactic Acid Bacteria: Microbi-ology, Genetics and Applications. Blackie Aca-


demic & Professional, London, pp. 539.De Vuyst, L., 1994. Bacteriocins and bacteriocin-

like substances from Lactobacillus. In:Bacteriocins of Lactic Acid Bacteria: Microbi-ology, Genetics and Applications.( De Vuyst,L., Vandamme, E.J. Eds.), Blackie Academic &Professional, London, pp. 319-330.

De Vuyst, L., 1996. Production and applicationsof bacteriocins from lactic acid bacteria.Bioactive peptides for future food preserva-tion. Cerevisia and Biotechnol. 21(1):71-74.

De Vuyst, L., R. Callewaert, and B. Pot, 1996.Characterization of the antagonistic activity ofLactobacillus amylovorus DCE 471 and large-scale isolation of its bacteriocin amylovorinL471. Syst. Appl. Microbiol., 19: 9-20.

Disks, L. M. T., D. E. Van Jaarsveld, H. J. J. VanVuuren, 1992. Caseicin LHS, a broad spec-trum bacteriocin produced by Lactobacilluscasei. Abstracts Book 7th Bienniul Congressof the South African Soc. Microbiol., pp 214.

Dodd, H. M. and M. J. Gasson, 1994. Bacterio-cins of lactic acid bacteria. In: Genetics andBiotechnology of Lactic Arid Bacteria (GassonM. J. & De Vos W.M. Eds.) Blackie Academic& Professional, London, pp 211-251.

Dobrogosz, W. J., B. L. Black, and I. A. Casas,1991. Delivery of viable Lactobacillusreuteri to the gastrointestinal tract of poultry.Poultry Sci., 70 (Suppl. 1.): 158 (Abstr.).

Drago, L., M. R. Gismondo, A. Lombardi, C. deHaën, and L. Gozzini, 1997. Inhibition of invitro growth of enteropathogens by new Lac-tobacillus isolates of human intestinal origin.FEMS Microbiol. Lett. 153: 455-463

Drasar, B. S. and M. J. Hill, 1974. Human Intes-tinal Flora. Academic Press, London (UK),pp.263.

Dubos, R., 1966. The microbiota of the gastrointes-tinal tract. Gastroenterology, 51: 868-892.

Ducluzeau, R., 1984. Microbial interactions inthe digestive tract. In: The Germ-free Animalin Biomedical Research, (M.E. Coates & B.E.Gustafsson Eds.), Laboratory Animals Ltd.,London, pp. 141-54.

Dunne, C., L. O’Mahony, L. Murphy, G.Thornton,D. Morrissey, S. O’Halloran,2001. In vitro selection criteria for probiotic

bacteria of human origin: correlation with invivo findings. Am. J.Clin. Nutr. 73 (suppl):386S-392S.

Du Toit, M., L. M. T. Dicks, and W. H. Holzapfel,2001. Taxonomy of obligately homofermen-tative and facultatively heterofermentative lac-tobacilli in pig faeces. Letters in Appl.Microbiol,. 32: 199-204.

Edelman, S., 2005. Mucosa-Adherent Lactoba-cilli: Commensal and Pathogenic Characteris-tics. Academic Dissertation, University ofHelsinki, Helsinki, Finland, pp. 81.

Edens, F. W., C. R. Parkhurst, and I. A.Casas,1993. Gaia Feedâ in commercial turkeyproduction. II Influence of Salmonella on liv-ability. Poultry Sci. 72 (Suppl.1.):163.

Edens, F. W., C. R. Parkhurst, I. A. Casas, andW. J. Dobrogosz, 1997. Principles of Ex OvoCompetitive Exclusion and In ovo Administra-tion of Lactobacillus reuteri. Poultry Sci.,76:179-196.

Edwards, C. A., B. I. Duerden, and N. W. Read,1985. The effect of pH on colonic bacteriagrown in continuous culture. J. Med.Microbiol,. 19:169-173.

Ehrich, M., J. E. Aswel, R. L.Van Tassell, and T.D. Wilkins, 1979. Mutagens in feces of 3South African populations at different levelsof risk for colon cancer. Mutat. Res., 64:231-236.

Ender, F. A. and L. Ceh, 1968.Occurrence of nit-rosamines in foodstuffs for human and animalconsumption. Food Cosmet. Toxicol., 6:569-572.

Ewing, W. N., 1994. The living gut: an introduc-tion to microorganisms in nutrition. Dungannon,UK, Context Publication, pp 222.

Eyssen, H., 1973. Role of the gut microflora inmetabolism of lipids and sterols. Proc. Nutr.Soc., 32:59-63.

Ferguson, L. R., P. G. Alley, and B.M. Guffin,1985. DNA-damaging activity in ethanolsoluble fractions of feces from New Zealandgroups at varying risks of colorectal cancer. Nutr.Cancer, 7:93-96.

Fernandes, C. F., K. M. Shahani, and M. A.Amer, 1987. Therapeutic role of dietary lacto-bacilli and lactobacilli fermented dairy prod-

S. A. Denev96

ucts. FEMS Microbial. Rev. 46: 343-356.Fernandes, C. F., K. M. Shahani, and M.

A.Amer, 1988. Control of diarrhea by lactoba-cilli. J.Appl. Nutrition, 40: 32-43.

Fernandes, C. F. and K. M. Shahani, 1989.Modulation of antibiosis by lactobacilli andother lactic cultures and fermented foods.Microbiologie-Aliments-Nutrition, 7: 337-352.

Fernandes, C. F. and K. M. Shahani, 1990.Anticarcinogenic and immunological propertiesof dietary lactobacilli, J. Food Prot., 53:704-710.

Ferrari, A., N. Pacine, and E. Canzi, 1980. Anote on bile acid transformation by strains ofBifidobacterium. J. Appl. Bacteriol. 49:193-197.

Floch, M. H., W. Gershengoren, S. Elliot, andH. M. Spiro, 1971. Bile acids inhibition of theintestinal microflora -a function for simple bileacids. Gastroenterology, 61: 228-232.

Floch, M. H., H. J. Binder, B. Filburn, and W.Gershengoren, 1972. The effect of bile acidson intestinal microflora. Am. J. Clin. Nutr.,25:418-1426.

Fredericq, P., 1948. Actions antibiotiquesreciproques chez les Enterobacteriaceae, Rev.Belg. Pathol. Med. Exp., 19 (Suppl. 4):1-107.

Friend, B. A, R. E. Farmer, and K. M. Shahani,1982. Effect of feeding and intraperitonealimplantation of yogurt culture cells on Ehrlichascites tumor. Milchwissenschaft, 37:708-710.

Friend, B. A. and K. M. Shahani, 1984. Antitu-mor properties of lactobacilli and dairy prod-ucts fermented by lactobacilli. J. Food Prot.47:717-723.

Friend, B. A. and K.M. Shahani, 1984a. Nutri-tional and therapeutic aspects of lactobacilli. J.Appl. Nutr., 36:125-153.

Fujisawa, T., S. Shirasaka, J. Watabe and T.Mitsuoka, 1984. Lactobacillus aviariussp.nov.: A new Species Isolated from theintestine of chickens. Syst. Appl. Microbiol., 5:414-420.

Fujisawa, T., Y. Benno, T. Yaeshima, and T.Mitsuoka, 1992. Taxonomic study of the Lac-tobacillus acidophilus group, with recognitionof Lactobacillus gallinarum sp. nov. and Lac-tobacillus johnsonii sp. nov. and synonymy of

Lactobacillus acidophilus group A3 (Johnsonet al. 1980) with the type strain of Lactobacil-lus amylovorus (Nakamura 1981). Int. J. Syst.Bacteriol. 42: 487–491.

Fujiwara, S., Y. Seto, A. Kimura, and H.Hashiba 2001. Establishment of orally admin-istered Lactobacillus gasseri SBT2055SR inthe gastrointestinal tract of humans and its in-fluence on intestinal microflora and metabo-lism. J. of Appl. Microbiol. , 90: 343-352.

Fuller, R. and A.Turvey, 1971. Bacteria associ-ated with the intestinal wall of the fowl (Gallusdomesticus). J. Appl. Bacteriol. 34: 617-22.

Fuller, R., 1973. Ecological studies on the lacto-bacillus flora associated with the crop epithe-lium of the fowl. J. Appl. Bacteriol,. 36: 31- 39.

Fuller, R., 1975. Nature of the determinant re-sponsible for the adhesion of lactobacilli tochicken crop epithelial cells. J. Gen. Microbiol.,87: 245-50.

Fuller, R., 1978. Epithelial attachment and otherfactors controling the colonization of the in-testine of gnotobiotic chicken by lactobacilli.J. Appl. Bacteriol., 45: 389-95.

Fuller, R., P. A. Barrow, and B. K. Srooker, 1978.Bacteria associated with the gastric epitheliumof neonatal pigs. Appl. Environ. Microbiol., 35:582- 91.

Fuller, R. and B. E. Srooker, 1980. The attach-ment of bacteria to the squamous epithelial cellsand its importance in the microecology of theintestine. In: Microbial Adhesion to Surfaces.(Eds R.C.W. Berkeley, J.M. Lynch, J. Me11ing,P.R. Rutter and B. Vincent). Pp. 495- 507.

Fuller, R., 1992. Probiotics, The Scientific Basis.Chapman & Hall, London, pp 398.

Fuller, R., 1997. Probiotics 2, Aplications and prac-tical aspects. Chapman & Hall, London, pp.212

Fuller, R. and G. Perdigon, 2000. Probiotics 3.Immunomodulation by the gut microflora andprobiotics. (R. Fuller and G. Perdigon Eds.).Kluwer Academic Publishers, Dordrecht.

Garg, S. K. and B. K. Mital, 1992. Genetics ofantagonistic action and drug resistance in Lac-tobacillus acidophilus. World J. Microbiol.Biotechnol. 8:92-97.

Gasson, M. J. and W. M. De Vos, 1994. Genetics


and Biotechnology of Lactic Acid Bacteria.B1ackie Academic & Professional, an imprintof Chapman A Hall,Glasgow, UK, pp. 295.

Gibson, G. R., J. M. Saavedra, S. Macfarlane,and G. T. Macfarlane, 1997. Probiotics andintestinal infections. In: Probiotics 2. Applica-tions and practical aspects (R. Fuller Ed.),Chapman & Hall, London, pp 10-39.

Geis, A., 1989. Antagonistic compounds producedby lactic acid bacteria. Kieler Milchwir-tschaftliche Forschungs-berichte, 41: 97-104.

Gill, C., and I. Rowland, 2003. Cancer. In Func-tional Dairy Products. (Eds. Sandholm, T.M.,and M. Saarela), Woodhead Publishing Lim-ited, Cambridge, England, pp 20-53.

Gilliland, S. E., M. L. Speck and C.G. Morgan,1975. Detection of Lactobacillus acidophilusin faeces of humans pigs and chickens. Appl.Microbiol., 30: 541-45.

Gilliland, S. K. and M. L. Speck, 1977. An-tagonistic action of Lactobacillus acidophilustoward intestinal and food-borne pathogens inassociative cultures. J. Food Prot., 40: 820-823.

Gilliland, S. K. and M. L. Speck, 1977a.Deconjugation of bile acids by intestinal lacto-bacilli. Appl. Environ. Microbiol., 33: 15-18.

Gilliland, S.E., M. L. Speck, G. F. Nauyok, andF. G. Giesbreeht, 1978. Influence of consum-ing non-fermented milk containing Lactobacil-lus acidophilus on fecal flora of healthy males.J. Dairy Sci., 61:1-3.

Gilliland, S. E., 1979. Beneficial interrectionshipsbetween certain microorganisms and humans:candidate microorganisms for use as dietary ad-juncts. J. Food Prot., 42: 164-167.

Gilliland, S. E., B.B. Bruce, I. J. Bush, and T. E.Staley, 1980. Comparison of two strains ofLactobacillus acidophilus as dietary adjunctsfor young calves.J. Dairy Sci., 63: 964-970.

Gilliland, S. E., C. R. Nelson, and C. V. Max-well, 1985. Assimilation of cholesterol by Lac-tobacillus acidophilus . Appl. Environ.Microbiol., 49:377-3S1.

Gilliland, S. E., 1989. Acidophilus milk prod-ucts: A review of potential benefits to con-sumers. J. Dairy Sci., 72: 2483-2494.

Gilliland, S. E., 1990. Health and nutritional ben-efits from lactic acid bacteria. FEMS Microbiol.

Rev., 7: 175-188.Gilliland, S. K. and D. K. Walker, 1990. Factors

to consider when selecting a culture of Lacto-bacillus acidophilus as a dietary adjunct to pro-duce a hypocholesterolemic effect in humans.J. Dairy Sci., 73: 905-911.

Goepfert, J. M. and R. Hicks, 1969. Effect ofvolatile fatty acids on Salmonella typhimurium.J. Bacteriol., 97: 956-960.

Goldin, B. R. and S. L. Gorbach, 1976. The rela-tionship between diet and fecal bacterial en-zymes implicated in colon cancer. J. Natl. Can-cer Inst., 57: 371-375.

Goldin, B. R. and S. L. Gorbach, 1977. Alter-ations in fecal microflora enzymes related todiet, age, Lactobacillus supplements and dim-ethylhydrazine. Cancer, 40: 2421-2425.

Goldin, B. R. and S. L. Gorbach, 1980. Effect ofLactobacillus acidophilus dietary supplementson 1,2-dimethilhydrazine dihydro-chloride-in-duced intestinal cancer in rats. J. Natl. CancerInst,. 64: 263-265.

Goldin, B. R., L. Swenson, J. Dwyer, M. Sex-ton, and S. L. Gorbach, 1980. Effect of dietand Lactobacillus acidophilus supplements onhuman fecal bacterial enzymes. J. Natl. Can-cer Inst., 64: 55-260.

Goldin, B. R. and S. L. Gorbach, 1983. The ef-fect of oral administration of Lactobacillus andantibiotics on intestinal bacterial activity andchemical induction of large bowel tumors.Dev.Ind. Microbiol., 25: 139-150.

Goldin, B. R. and S. L.Gorbach, 1984. The effectof milk and lactobacillus feeding on human in-testinal bacterial enzyme activity, Am, J. Clin.Nutr., 39: 756-761.

Goldin, B. R. and S. L. Gorbach, 1992. Probioticsfor humans. In: Probiotics, The Scientific Ba-sis (Ed. Fuller, R.), Chapman & Hall, London,pp. 355-376.

Goldin, B. R., S. L. Gorbach, M. Saxelin, S.Barakat, L. Gualtieri, and S. Salminen,1992. Survival of Lactobacillus species (strainGG) in human gastrointestinal tract. Dig. Dis.Sci., 37: 121-128.

Goldin, B. R., L. Gualtieri, and R. Moore, 1996.The effect of Lactobacillus GG on the initia-tion and promotion of dimethilhydrazine-in-

S. A. Denev98

duced intestinal tumors in the rat. Nutr. Can-cer, 25: 197- 204.

Gonzalez, B., P. Area, B. Mayo, and J. E.Suarez, 1994. Detection, purification, andpartial characterization of Plantacin C, a bacte-riocin produced by a Lactobacillus plantarumstrain of dairy origin. Appl. Environ. Microbiol.,60: 2158-2163.

Gopal-Srivastava, R. and P. B. Hylemon, 1988.Purification and characterization of bile salt hy-drolase from Clostridium perfringens. J. LipidRes., 29: 1079-1085.

Gorbach, S. L., 1990. Lactic acid bacteria and hu-man health, Ann. Medicine, 22:37-47.

Gotz, F., B. Sedewitz, and E. F. Elstner, 1980.Oxygen utilization by Lactobacillus plan-tarurn. I, Oxygen consuming reactions. Arch.Microbiol., 125: 209.

Gratia, A., 1925. Sur un remarquable exemple d’an-tagonisme entre souches de colibacille. C. R.Soc. Biol., 93:1040-1041.

Grill, J. P., C. Mangfnot-Durr, F. Schneider,and J. Ballongue, 1995. Bifidobacteria andprobiotic effects: Action of Bifido-bacteriumspecies on conjugated bile salts. CurrentMicrobiol., 31:23-27.

Grill, J. P., C. Cayuela, J. M. Antoine, and F.Schneider, 2000. Isolation and characteriza-tion of a Lactobacillus amylovorus mutant de-pleted in conjugated bile salt hydrolase activ-ity: relation between activity and bile salt re-sistance. J. Appl. Microbiol,. 89:553-563.

Grossowics, N., D. Kaplan, and S. Schneerson,1947. Production of an antibiotic substance bya Lactobacillus. Proceedings IV InternationalCongress of Microbiology, Copen-hagen, pp.137-138.

Groucher, S. C., A. P. Houston, C. E. Bayliss,and R. J. Turner, 1983. Bacterial populationsassociated with different regions of human co-lon wall. Appl. Environ. Micro-biol., 45:1025-1029.

Guilliams, T.G., 1999. Healthy Microbial Organ-isms, The Standard, 2(2):1-7.

Gurr, M. I., 1987. Nutritional aspects of fermentedmilk products. FEMS Microbiol. Rev., 46:337-342.

Gusils, C., J. Palacios, S. Gonzalez, and G.

Oliver, 1999. Lectin-like protein fractions inlactic acid bacteria isolated from chickens. Biol.Pharm. Bull., 22:11–15.

Gusils, C.J., S. Cuozzo, F. Sesma, and S.Gonzales, 2002. Examination of adhesive de-terminant in three species of Lactobacillus iso-lated from chicken. Can. J. Microbiol., 48:34-42.

Gusils, C., F. Cuozzo, F. Sesma, and S.Gonzales, 2002a.Examination of adhesive de-terminants in three species of Lactobacillus iso-lated from chicken. Can. J. Microbiol., 48:34-42.

Gusils, C., O. Oppezzo, R. Pizarro, and S.González, 2003. Adhesion of probiotic lacto-bacilli to chick intestinal mucus. Can. J.Microbiol., 49: 472-478.

Haberer, P., Du Toit, F. Ahrens, and W. H. Holz-apfel, 1995. Assessment of probioticcharacteristics of lactic acid bacteria andevaluation of serum cholesterol reduction in aminipig feeding trial. Conference on Lactic AcidBacteria “Improvement of Lactic Acid Bacteriafor Traditional and Novel Applications inBiotechnology”, 22- 26 October 1995, Cork,Ireland, Book of Abstracts, pp. 38.

Haenel, H., W. Muller-Beuthow, and A.Scheunert, 1957. Der Einfluss extremer Kost-formen auf die faekale Flora des Menschen IEinleitung und Versuchsabsichten, Zbl. Bakt. IOrig., 168: 37.

Haenel, H., W. Muller-Beuthow, and A.Scheunert, 1957a. Der Einfluss extremer Kost-formen auf die faekale Flor des Menschen I.Zbl. Bakt. I Orig., Abt. A. 169: 45.

Haenel, H., 1970. Human normal and abnormalgastrointestinal flora. Am. J. Clin. Nutr., 23:1433-1437.

Haenel, H., 1980. Die gastrointestinale Microflorain Abhangigkeit von Milieu und Ernahrung,Mikrobielle Umwelt und Massnahmen, 4:17.

Halliwell, B., 1978. Superoxide-dependent for-mation of hydroxyl radicals in the presence ofiron chelates. FEBS Lett., 92:321-326.

Hamdan, I. Y. and E. M. Mikola]cik, 1973.Growth, viability and antimicrobial activity ofLactobacillus acidophilus. J. Dairy Sci. 56:638.

Hamdan, I. Y. and E. M. Mikolajcik, 1974.


Acidolin: an antibiotic produced by Lactoba-cillus acidophitus. J. Antibiot. 27: 631-636.

Hammes, W. P., N. Weiss, and W. H. Holzapfel,1991. The genera Lactobacillus and Carno-bac-terium. In: The Prokaryotes. Handbook on theBiology of Bacteria: Ecophysiology, Isolation,Identification, Applications (Eds A. Balows,H.G. Truper, M. Dworkin, Harder, W. and K.H.Springer), New York, USA, pp. 1535-94.

Hammes, W. P., and R. F. Vogel, 1995. The genusLactobacillus. In: The Lactic Acid Bacteria, Vol.2., The Genera of Lactic Acid Bacteria (EdsB.J.B. Wood and W.H. Holzapfel), Blackie Aca-demic Professional, an imprint of Chapman &Hall, Glasgow, UK, pp. 19-54.

Hargrove, R. K. and J. A. Alford, 1978. Growthrate and feed efficiency of rats fed yogurt andother fermented milks. J. Dairy Sci., 61:11-15.

Harris, L. J., M. A. Daechsel, M. E. Stiles, andT. R. Klaenhammer. 1989. Antimicrobial ac-tivity of lactic acid bacteria against Listeriamonocytogenes. J. Food Prot., 52: 384-387.

Hautefort, I., M. Ladire, P. Raibaud, R.Ducluzeau, and M. Fons, 1996. Descriptionof a model sings colonizing and non-colonizingLactobacillus fermentum strains for potentialexpression of new functions in vivo. Fifth Sym-posium on Lactic Acid Bacteria, Genetics, Me-tabolism and Applications,(Abstracts), Veldho-ven, The Netherlands, September 8/12, J10.

Hawksworth, G., B. S. Drasar, and M. J. Hill,1971. Intestinal bacteria and the hydrolysis ofglycoside bonds., J. Med. Microbiol., 4:451-453.

Hawksworth, G., and M. J. Hill, 1971. Bacteriaand the N-nitrosation on secondary amines. Br.J. Cancer, 25:520-524.

Hawley, H.B., P. A. Shepherd, and D. M.Wheater, 1959. Factors affecting the implan-tation of lactobacilli in the intestine. J. Appl.Bacteriol., 22:360-365.

Hayakawa, S., 1973. Microbial transformationof bile acids. Adv. Lipid Res., 11:143-192.

Heinemann, C., J. E. T., van Hylcama Vlieg, D.B. Janssen, H.J. Busscher,H. C. van der Mei,and G. Reid, (2000) Purification and charac-terization of a surface-binding protein from Lac-tobacillus fermentum RC-14 that inhibits ad-

hesion of Enterococcus faecalis 1131. FEMSMicrobiol. Lett,. 190:177-180.

Herich, R., Revajova, V., Levkut, M., Bomba,A., Nemcova, A., Guba, P., andGancarcikova, S. 2002. The effect of L.paracasei and Raftilose P95 upon the non-spe-cific immune response of piglets. Food andAgric. Immunol., 14:171-179.

Hill, M. J. and B. S. Drasar, 1968. Degradationof bile salts by human intestinal bacteria.Gut..9:22-27.

Hill, M. J., M. J. Hudson, S. P. Borriello, 1982.Factors control the intestinal flora. Europ. J.Chemother. Antibiot., 2:51-56.

Hill, M. J. ,1986. Microbes and Human Carcino-genesis. Arnold, London, pp 345.

Hirano, S., R. Nakama, M. Tamaki, N. Masuda,and H. Oda, 1981. Isolation and characteriza-tion of thirteen intestinal microorganisms ca-pable of 7 a-dehydroxylating bile acids, Appl.Environ. Mtcrobiol., 41:737-745.

Hoepelman, A. I. M. and E. I. Tuomanen, 1992.Consequences of microbial attachment. Directhost cell functions with adhesins. A mini re-view. Infect. Immun., 60:1729-34.

Hofmann, A.F. and K. Mehjian, 1973. Bile acidsand the intestinal absorbtion of fat andelectrolytes in health and disease. In: The BileAcids: chemistry, physiology and metabolism.II. Physiology and metabolism. (Nair, P.P. andKritchevsky, D. Eds.), Plenum Press, NewYork, pp. 103-152.

Hollister, A. G., D. E. Corrier, D. J. Nisbet, R.C. Beier, and J. B. DeLoach, 1995. Effect oflyophilization in sucrose plus dextran andrehydratation in thioglycolate btorh on the per-formance of competitive exclusion cultures inbroiler chicks. Poultry Sci., 74:586-590.

Holzapfel, W.H., P. Haberer, R. Geisen, J.Bjorkroth, and U. Schillinger, 2001.Taxonomy and important features of probioticmicroorganisms in food and nutrition. Am. J.Clin. Nutr., 73 (suppl):365S-373S.

Honma, N., 1986. On effect of lactic acid bacteria.Part I. Biological significance. New Medicinesand Clinics, 35 (12): 2687-2695.

Honma, N., K. Ohtani, and H. Kikuchi, 1987.On effects of lactic acid bacteria. Part II. Clini-

S. A. Denev100

cal effects. New Medicines and Clinic, 36(1):75.Hood, S.K. and E. A. Zottola, 1987. An electronic

microscopic study of the adherence propertiesof Lactobacillus acidophilus. J. Food Sci. 52:791-97.

Hoover, D. and L. Steenson, 1993. Bacteriocinsof Lactic Acid Bacteria. Academic Press, NewYork, pp. 21-121.

Horakova, Z., C. H. Zefrdt, and M. A. Zeaven,1971. Identification of Lactobacillus as thesource of bacterial histidine decarboxylase inrat stomach. Europ. J. Pharmacol., 16: 67-77.

Horie, M., A. Ishiyama, Y. Fujihira-Ueki, J.Sillanpää, T. K. Korhonen, and T. Toba,2002. Inhibition of the adherence of Escheri-chia coli strains to basement membrane by Lac-tobacillus crispatus expressing an S-layer. J ApplMicrobiol., 92: 396-403.

Hosoda, M., H. Hashimoto, F. He, H. Morita,M. Chiba, and A. Hosono, 1992a. Studies onantimutagenic effects of lactic acid bacteria onTrpP-2 induced mutagenicity to TA 98 strainof Salmonella typhimurium. J. Dairy Sci., 59:543-549.

Hosoda, M., H. Hashimoto, F. He, H. Morita,M. Chiba, and A. Hosono, 1992b.Antimutagenicity of milk cultured with lacticacid bacteria against N-metyl-N’-nitro-soguanidin. J. Dairy Sci., 75:970-981.

Hosoda, M., H. Hashimoto, F. He, H. Morita, A.Hosono, 1996. Effect of administration of milkfermented with Lactobacillus acidophilus LA-2 on fecal mutagenicity and microflora in thehuman intestine. J. Dairy Sci., 79:745-749.

Hosono, A., K. Yastuld, and F. Tokita, 1977. Iso-lation and characterization of an inhibitory sub-stance against Escherichia coli produced byLactobacillus acidophilus. Milchwissenschaft,32: 727-730.

Hosono, A., S. Sagae, and F. Tokita, 1986a.Desmutagenic effect of cultured milk on chemi-cally induced mutagenesis in Escherichia coliB/r WP2 trp her. Mlchwissenschaft, 41:142-145.

Hosono, A., T. Kashina, and T. Kada, 1986b.Antimutagenic properties of lactic acid-culturedmilk on chemical and fecal mutagens. J. DairySci., 69:2237-2242.

Hosono, A., 1988a. Preventive effects of lactic acidbacteria against carcinogenesis. Food Industry,31(16):244-251.

Hosono, A., 1988b. The role of lactic acid bacteriaas scavenger of N-nitrosocompounds in theintestinal tract. Bull. Jap. Dairy TechnicalAssoc., 38(3): 1-17.

Hosono, A., R. Wardojo, and H. Otani, 1990.Binding of amino acid pyrolyzates by lacticacid bacteria isolated from “Dadih”.Lebensmittel-Wissenschaft und-Technol.,23:149-153.

Hosono, A., 1992. Diet and mutagenic toxicity.In: Functions of Fermented Milks. Challengesfor the Health Sciences (Eds. Nakazawa, Y. andHosono, A.), Elsevier Applied Science, Lon-don and New York, pp. 103-126.

Hosono, A., H. Kitazawa, and T. Yamaguchi,1997. Antimutagenic and antitumour activitiesof lactic acid bacteria. In: Probiotics 2,Aplications and practical aspects (Ed.R.Fuller), Chapman & Hall, London, pp. 89-132.

Hylemon, P. B. and T. J. Glass, 1983. Biotrans-formation of bile acids and cholesterol by theintestinal microflora. In: Human IntestinalMicroflora in Health and Disease. (Ed. Hentges,D.J.), Academic Press, Inc., New York, pp.189-213.

Imaizumi, K, K. Hirata, M. Zommara, M.Sugano, and Y. Suzuki, 1992. Effects of cul-tured milk products by Lactobacillus andBifidobacterium species on the secretion of bileacids in hepatocytes in rats. J. Nutr. Sci. andVitaminol., 38:343-351.

Isolauri E., Y. Sutas, P. Kankaanpaa, H.Arvilommi, and S. Salminen, 2001.Probiotics: effects on immunity. Am. J. Clin.Nutr., 73 (suppl):444S-450S.

James, R., C. Lazdunski, and F. Pattus, 1992.Bacteriocins, Microcins and Lantibiotics.Springer-Verlag, Berlin, Heidelberg. pp.124-156.

Jimenez-Diaz, R., J. C. Piard, J. L. Ruiz-Barba,and M. J. Desmazeaud, 1990. Plantacins Sand T, two new bacteriocins produced by Lac-tobacillus plantarum LPCO 10 isolated from agreen olive fermentation. Appl. Environ.Microbiol., 59:1416-1424.


Jin, L.Z., Y.W., Ho, M. A. Ali, N. Abdullah, andS.Jalaludin, 1996. Effect of adherent Lacto-bacillus spp. on in vitro adherence of salmo-nellae to the intestinal epithelial cells of chicken.J. Appl.Bacteriol, . 81: 201-206.

Jin, L.Z., Y.W., Ho, N. Abdullah, M.A. Ali, andS. Jalaludin, 1998. Lack of influence of ad-herent Lactobacillus isolates on the attachmentof Escherichia coli to the intestinal epithelialcells of chicken in vitro. J. Appl. Microbiol.,84:1171-1174.

Joerger, M. C. and T. R. Klaenhammer, 1986.Characterization and purification of HelveticinJ and evidence for a chromosomally determinedbacteriocin produced by Lactobacillushelveticus 481. J. Bacteriol., 167(2):439-446.

Johnson, M. S., B. Ray, and T. Bhowmik, 1987.Selection of Lactobacillus acidophilus strainsfor use in “acidophilus products”. Antonie vanLeeuwenhoek, 53: 215-31.

Juven, B J., F. Schved, and P.Lindner, 1992.Antagonistic compounds produced by achicken intestinal strain of Lactobacillus aci-dophilus. J. Food Prot., 55 (3): 155-161.

Kaila M., E. Isolauri, E. Soppi, E. Virtanen, S.Laine, H. Arvilommi, 1992. Enhancement ofthe circulating antibody secreting cells responsein human diarrhea by human lactobacillus strain.Pediatr. Res, 32:141-144.

Kaila M., E Isolauri., M. Saxelin, H. Arvilommi,T. Vesikan, 1995. Viable versus inactivatedLactobacillus strains GG in acute rotavirus di-arrhoea. Arch. Dis. Child, 72:51-53.

Kanatani, K., T. Tahara, K. Yoshida, H. Miura,M. Sakamoto, and M. Oshimura, 1992. Plas-mid-associated bacteriocin production by andimmunity of Lactobacillus acidophilusTK8912. Biosci. Biotechnol. Biochem., 56:648-651.

Kanatani, K., M. Oshimura, and K. Sano, 1995.Isolation and characterization of Acidocin Aand cloning of the bacteriocin gene from Lacto-bacillus acidophilus. Appl. Environ. Microbiol,.61: 1061-1067.

Kanbe, M., 1988. Control of tumorigenesis andfermented milk. New Food Industry, 30 (1):77-87.

Kanbe, M., 1992. Uses of intestinal lactic acid

bacteria and health. In: Functions of FermentedMilks. Challenges for the Health Sciences(Nakazawa, Y. and Hosono, A. Eds.) ElsevierApplied Science, London and New York, pp.289-304.

Kandler, O., 1983. Carbohydrate metabolism inlactic acid bacteria. Antonie Van Leeuwen-hoek,49:209-213.

Kashet, E. R., 1987. Bioenergetics of lactic acidbacteria: cytoplasmic pH and osmotole-rance.FEMS Microbiol. Rev., 46:233.

Kato, I., T. Yokokura, and M. Mutai, 1984. Aug-mentation of mouses natural killer cell activityby Lactobacillus casei and its surface antigens.Microbiol. Immunol., 28:209-217.

Kato, I., K. Endo and T. Yokokura, 1994. Effectsof oral administration of Lactobacillus casei onantitumor responses induced by tumor resec-tion in mice. Int. J. Immunophar-mac. 16:29-36.

Kaur, I. P. K. Chopra, and A. Saini, 2002.Probiotics: potential pharmaceutical applica-tions. Eur. J. of Pharmaceutical Sciences, 15:1-9.

Kavasnikov, F. J. and I. Sudenko, 1967. Antibi-otic properties of Lactobacillus brevis.Microbiol. J., (Kiev), 29:146.

Kim, H. S., 1989. Effects of fermented milk onthe ecology of the intestine and host benefits.In: Fermented Milks and Health. Proceedingsof a workshop held on September 26-26,Arnhem, The Netherlands, pp 15-32.

Kinoshita, N. and H. V. Gelboin, 1978. b-Glucu-ronidase catalyzed hydrolysis of benzo(a)pyrene-3-glucuronide and binding to DNA.Science, 199: 307-309.

Kishi, A., K. Uno, Y. Matsubara, C. Okuda,and T. Kishida, 1996. Effect of the oral ad-ministration of Lactobacillus brevis subsp.coagulans on a-interferon producing capacityin humans. J. Am. College. Nutr., 15: 408-412.

Klaenhammer, T. R., 1988. Bacteriocins of lacticacid bacteria, Biochimie, 70: 337-349.

Klaenhammer, T. R., 1993. Genetics of bacterio-cins produced by lactic acid bacteria. FEMSMicrobiol. Rev., 12: 39-85.

Klaenhammer, T. R., 1995. Genetics of Intesti-nal Lactobacilli. Int. Dairy J., 5:1019-1058.

S. A. Denev102

Klaenhammer, T. R., 1997. Probiotic Roles ofLactobacilli-genetic imperatives and op-portunities. International Symposium on LacticAcid Bacteria and Human Health. Korean Pu-blic Health Association, Seul, pp. 79-97.

Klaenhammer, T. R., 1997a. Functional activitiesof Lactobacillus probiotics: genetic mandate.Proceedings of the US/Ireland InternationalSymposium on Functional Foods: DesignerFoods for the Future, 17, Abstract SP20.

Klaenhammer, T. R., 1997b. Current research de-velopments on lactic acid bacteria probiotics,baxteriocins, and bacteriophages. RhonePoulenc, Madison, Wisconsin, May 1997,USA.

Klein, G., A. Pack, C. Bonaparte, and G. Reuter,1998. Taxonomy and physiology of probioticlactic acid bacteria. International Journal ofFood Microbiology, 41:103-125.

Kobashi, K. I., T. Nishizava, T. Yamada, and J.Hase, 1978. A new hydrolase specific for tau-rine conjugates of bile acids. J. Biochem. ,(To-kyo) 84: 495-497.

Kodama, R., 1952. Studies of lactic acid bacteria.2. Lactolin - a new antibiotic substance pro-duced by lactic acid bacteria. J. Antibiot., 5:72-74.

Kopeloff, N., 1926. Lactobacillus acidophilus. Wil-liams and Wilkins, Baltimore.

Kopp-Hoolihan, L., 2000. Prophylactic andtherapeuric uses of probiotics: a review. J. Am.Diet. Assoc.,101(2):229-238.

Kotarski, S. F. and D. S. Savage, 1979. Modelsfor study of the specificity by which indig-enous lactobacilli adhere to murine gastric epi-thelia. Infect. Immun., 26: 966-75.

La Ragione, R. M., A. Narbad, M.J. Gasson,and M.J. Woodward, 2004. In vivo character-ization of Lactobacillus johnsonii FI9785 foruse as a defined competitive exclusion agentagainst bacterial pathogens in poultry. Lett. Appl.Microbiol., 38:197-205.

Larpent, J. P., 1994. Les proteines antimicro-biennes. In: Les Probiotiques en AlimentationAnimale et Humaine (Eds. Chateau, N.G.,Larpent, J.P., Castellanos, M.I. and Larpent,1. L.), Technique & Documentation, Lavoisier,Paris, pp. 49-68.

Lascar, V., 1995. Yoghurt and cultured milks. Un-likely probiotic food models. Latte, 20:352-356.

Law, M. R., N. J. Wald, T. Wa, A. Hackshaw, andA. Bailey, 1994 Systematic underestimationof association between serum cholesterol con-centration and ischaemic heart disease in ob-servational studies. Br. Med. J. , 308: 363-366.

Lederman, M., R. L. Van Tassell, S. K. H. West,M. F. Ehrich, and T. D.Wilkins, 1980. In vitroproduction of fecal mutagen. Mutat. Res., 79:115-118.

Lee, Y.-K., K. Y. Puong, A. C. Ouwehand, andS. Salminen, 2003. Displacement of bacterialpathogens from mucus and Caco-2 cell surfaceby lactobacilli. J. Med. Microbiol., 52:925-930.

Lichtenstein, A. H. and B. R. Goldin, 1993.Lactic Acid Bacteria and Intestinal Drug andCholesterol Metabolism. In: Lactic AcidBacteria (Eds.Salminen, S.& von Wright, A.)Marcel Dekker, Inc., New York, pp. 227-235.

Lidbeck, A., E. Overvik, J. Rafter, C. E. Nord,and J. A. Gustafsson, 1992. Effect of Lacto-bacillus acidophilus supplements on mutagenexcretion in faeces and urine in humans.Microbiol. Ecol. Health Dis., 5:59-02.

Lidbeck, A., U. Allinger, K. Orrhage, L. Ottova,S. Brismar, J. A. Gustafsson, J. Rafter, andC. K. Nord, 1991. Impact of Lactobacillus aci-dophilus supplements on the fecal microfloraand soluble fecal bile acids in colon cancer pa-tients. Microb. Ecol. Health Dis., 4:81-88.

Lin, J. H. C. and D. S. Savage, 1984. Host speci-ficity of the colonization of murine gastric epi-thelium by lactobacilli. FEMS Microbiol. Lett.,24:67-71.

Lin, S. Y., J.W. Ayres, W. Winkler, and W. E.Sandine, 1989. Lactobacillus effects on cho-lesterol: in vitro and in vivo results. J. DairySci., 72:2885-2889.

Lindgren, S. E. and W. J. Dobrogosz, 1990. An-tagonistic activities of lactic acid bacteria infood and feed fermentations. FEMS Microbiol.Rev., 87:149-164

Ling, W. N., R. Korpela, H. Mykkanen, S.Salminen, and O. Hanninen, 1994. Lacto-bacillus strain GG supplementation decreasedcolonic hydeolytic and reductive enzyme ac-


tivities in healthy female adults. J. Nutr.,124:18-23.

Lombardi, P., B. Goldin, K. Boutin, and S. L.Gorbach, 1978. Metabolism of androgens andestrogens by human fecal microorganisms. J.Steroid Biochem., 9:795-801.

Lovegrove, J., and K. Jackson, 2003. Coronaryheart disease. In: Functional Dairy Products(Sandholm, T.M. and Saarela, M. Eds.)Woodhead Publishing Limited and CRC PressLLC.Abington Hall, Abington Cambridge CB16AH, England.pp. 54-93.

Lu, J., U. Idris, B. Harmon, C. Hofaere, J. J.Maurer, and M. D. Lee, 2003. Diversity andsuccession of the intestinal bacterial commu-nity of the maturing broiler chicken. Appl.Environ. Microbiol., 69:6816-6824.

Luckey, T. D., 1972. Introduction to intestinalmicroecology. Am. L Clin. Nutr., 25: 1929-1994.

Lundeen, S. G. and D. C. Savage, 1990. Charac-terization and purification of bile salt hydro-lase from Lactobacillus ssp. strain 100-100. J.Bacteriol., 172:4171-4177.

Lundeen, S. G. and D. C. Savage 1992. Mul-tiple Forms of bile salt hydrolase from Lacto-bacillus ssp. strain 100-100. J. Bacteriol.,174:7217-7220.

Lys, M. B. and S. E. Gilliland 1994. Compari-sons of freshly isolated strains of Lactobacil-lus acidophilus of human intestinal origin forability to assimilate cholesterol during growth.J.Dairy Sci., 77:2925-2933.

Ma, L., E. Deitch, R. E. Specian Steffen, and R.Berg, 1990. Translocation of Lactobacillusmurinus from the gastrointestinal tract. Cur-rent Microbiol., 20: 177- 84.

Mackie R. I., A. Sghir and H. R. Gaskins, 1999.Developmental microbial ecology of the neo-natal gastrointestinal tract. Am. J. of Clin. Nutr.,69 (suppl):1035s-1045s.

Magee, P. N., 1971. Toxicity of nitrosamines: theirpossible human health hazards. Food Cosmet.Toxicol., 9:207-211.

Maier, B. R., M. A. Flynn, G. C. Burton, R. K.Tsutakawa and D. J. Hentges, 1974. Effectof high beef diet on bowel flora: a preliminaryreport. Am. L Clin. Nutr,. 27: 1470.

Malin, M., H. Svomalainen, M. Saxelin and E.Isolauri, 1996. Promotion of IgA immuneresponse in patients with Crohn’s diseaseby oral bacteria therapy with LactobacillusGG. Ann. Nutr. Metabol., 40: 137-145.

Mallory, A.D., D. Savage, F. Kern and J. G.Smith, 1973. Patterns of bile acids and micro-flora in human small intestine. II. Microflora.Gastroenterology, 64:34-39.

Manning, B. W., C. K. Cerniglia and T. W.Federle, 1985. Metabolism of benzidine basedazo dye Direct Black 38 by human intestinalmicrobiota, Appl. Environ. Microbiol., 50:1985-1989.

Marc, D., P. Arné, A. Brée, and M. Dho-Mou-lin, 1998. Colonization ability and pathogenicproperties of a fim- mutant of an avian strainof Escherichia coli. Res. Microbiol., 149:473-485.

Marteau, Ph., P. Philippe, B. Flourie, P. Pellier,L. Santos, J. F. Desjeux, and J. C. Rambaud,1990. Effect of chronic ingestion of a fermenteddairy product containing Lactobacillusacidophilus and Bifidobac-terium bifidum onmetabolic activities of colonic flora in humans.Am. J. Clin. Nutr., 52:685-688.

Marteau, Ph. and J. C. Rambaud, 1993. Poten-tial of using lactic acid bacteria for therapy andimmunomodulation in man. FEMS Microbiol.Rev., 12:207-220.

Marteau, Ph., 1995. Impact of ingested lactic acidbacteria on the immune response in man. Actesdu Colloque LACTIS 94, ( Eds. Nobel, G. &Le Querler, Jean-Francois) Caen 7-9 Septem-ber, 1994, Presses universitaires de Caen,Gedex, France, pp. 31-42.

Masuda, K., 1981.Deconjugation of bile salts byBacteroides and Clostridium. Microbiol.Immunol., 25:1-11.

Masuda, K and T. Kawata, 1980. Reassemly ofthe regular rearranged subunits in the cell wallof L. brevis and their reattachment to cell wall,Microbiol. Immunol., 24: 299-307.

Masuda, K. and T. Kawata, 1981. Characteriza-tion of a regular array in the wall of L buchneriand its reattachment to the other wall compo-nents. J. Gen. Microbiol., 124:81-88.

Matsuzani T., and J. Chin, 2000. Modulating

S. A. Denev104

immune responses with probiotic bacteria.Immunology and Cell Biology, 78:67-73.

Mattick, A.T.R. and A. Hirsch, 1947. Further ob-servations on an inhibitory substance (nisin)from lactic streptococci. Lancet, 2: 5-7.

Mayra-Makinen, A., M. Manninen and H.Gyllenberg, 1983. The adherence of lactic acidbacteria to the columnar epithelial cells of pigsand calves. J. Appl. Bacteriol., 55:241-245.

McCann, J.E., E. Choi, K. Yamasaki, and B. N.Ames, 1975. Detection of carcinogens as mu-tagens in the Salmonella/microsome test: As-say of 300 chemicals. Proc. of the NationalAcad. Sci. (U.S.), 72:5135-5139.

McCormick, E. and D. C. Savage, 1983. Charac-terization of Lactobacillus sp. strain 100-37from the murine gastrointestinal tract: Ecology,plasmid content, and antagonistic activity to-ward Clostridium ramosum H1. Appl. Environ.Microbiol., 46:1103-1112.

McIntosh, G. H., 1996. Probiotics and colon can-cer prevention. Asia Pacific J. Clin. Nutr., 5:48-52.

Mercenier, A., S. Pavan, and B. Pot, 2002.Probiotics as Biotherapeutic Agents: PresentKnowledge and Future Prospects. CurrentPharmaceutical Design, 8:99-110.

Melnoykowycz, J. and K. R. Johansson, 1955.Formation of amines by intestinal microorgan-isms and the influence of chlortetracycline, J.Experim., Med. 101:507-517.

Metchnikoff, E., 1903. The Nature of Man. Stud-ies of Optimistic Philosophy. Heinemann, Lon-don.

Metchnikoff, E., 1907. The Prolongation of Life,Heinemann, London.

Midtvedt, T. and A. Norman, 1968. Parametersin 7 dehydroxylation of bile acids by anaerobiclactobacilli. Acta Pathol. Microbiol Scand.,72:313-329.

Midtvedt, T., 1974. Microbial bile acid transfor-mation. Am. J. Clin. Nutr., 27:1341-1347.

Midtvedt, T. B., T. Carlstedt-Duke Hoverstad,A. C. Midtvedt, K. Norin, and H. Saxerhold,1987. Establishment of a biochemicaIy activeintestinal ecosystem in ex-germfree rats. Appl.Environ. Microbiol., 12: 2866-2871.

Miettinen, M., V. Vuopio, and K. Varkila, 1996.

Production of TNF, IL-6 and IL-10 is inducedby lactic acid bacteria. Fifth Symposium onLactic Acid Bacteria, Genetics, metabolism andApplications, (Abstracts), Veldhoven, TheNetherlands, September 8/12, J5.

Miguel, C. B., 2001.Microbiota and gastrointes-tinal system. Rev. Esp. Enferm Dig.(Madrid),93(5):328-330.

Mikelsaar, M. and R. Mandar, 1993. Develop-ment of Individual Lactic Acid Microflora inthe Human Microbial Ecosystem. Lactic AcidBacteria in Health and Disease. In: Lactic AcidBacteria (Eds. S. Salminen and A. von Wright),Marcel Dekker, Inc. New York, pp. 237-293.

Mikolajcik, E. M., and I. Y. Hamdan, 1975. Lac-tobacillus acidophilus. 2. Antimicrobial agents.Cult. Dairy Prod. J., 10:18-20.

Mishra, C., and I. Lambert, 1996. Production ofantimicrobial substances by probiotics. AsiaPac. J. Clin. Nutr,. 5:20-24.

Mital, B K., and S. K. Garg, 1992. Acidophilusmilk products: manufacture and therapeutics.Food Rev. Int. 8:347-353.

Mital, B. K., and S. K. Garg, 1995. Anti-carcino-genic, Hypocholesterolemic and AntagonisticActivities of Lactobacillus acidophilus. Criti-cal Rev. Microbiol., 21(3) 175-214.

Mitchell, I. D. G., and R. Kenworthy, 1976. In-vestigations on a metabolite from Lactobacil-lus bulgaricus which neutralizes the effect ofenterotoxin from Escherichia coli pathogenicfor pigs. J. Appl. Bacteriol., 41:163-174.

Mitsuoka, T., 1969. Verglichende Untersuchun-gen uber die Laktobazillen aus den Faeces vonMenschen Schweinen und Huhnern. Zentralbl.Bakt. Parasitenkd. Infectionskr. Abt. I Orig.,210:32-37.

Mitsuoka, T., K. Hayakawa, and N. Kimura,1975. Die Faekalflora bei Menschen. III Mit-teilung: Die Zusammensetzung der Lactoba-zillenflora der verschiedener Altersgruppen,Zentralbl.Bakt. Parasitenkd. Infectionskr. Abt.A,. 232: 499.

Mitsuoka, T., 1981. Intestinal flora and cancer.Second Annual National Symposium for Lac-tic Acid Bacteria and Health. Korea, pp.16-40.

Mitsuoka, T., 1984. Effect of lactic acid bacteria


and new application areas. J. Japan Food In-dustry 31 (4):285.

Mitsuoka, T. and T. Fujisawa, 1987. Lactoba-cillus hamsteri, a new species from the intes-tine of hamsters. Proceedings of Japan Acad-emy, (Series B), 63:269-272.

Mitsuoka, T., 1992. The Human GastrointestinalTract..In: The Lactic Acid Bacteria Vol.1., TheLactic Acid Bacteria in Health and Disease( Ed. Wood, B. J. B), Elsevier Applied Science,London and New York, pp. 69-114.

Mitsuoka, T., 1996. Intestinal flora and humanhealth. Asia Pac. J. Clin. Nutr., 5:2-9.

Moineau, S. and J. Goulet, 1991. Effect offeeding fermented milks on the pulmonarymacrophage activity in mice. Milchwissen-schaft, 46:551-553.

Molin, G., R. S. Andersson Ahrne, C. Lonner,I. Marklinder, M. L. Johansson, B. Jeppsson,and S. Bengmark, 1992. Effect of fermentedoutmeal soup on the cholesterol level and theLactobacillus colonization in rat intestinalmucosa. Antonie van Leeuwenhoek , 61:167-73.

Molin, G., M. L. Johansson Stahl M., S. Ahrne,R. Andersson, B. Jeppsson, and S.Bengmark, 1992a. Systematic of the Lacto-bacillus population on rat intestinal mucosawith special reference to Lactobacillus reuteri,Antonie van Leeuwenhoek 61:175-83.

Moore, W.E.C., and Holdeman, L.V., 1975. Dis-cussion of current bacteriological investigationsof the relationships between intestinal flora,diet and colon cancer. Cancer Res., 35:3418.

Morishita, T. Y., T. Mitsuoka, C. Kaneuchi, S.Yamamoto, and M. Ogata, 1971. Specific es-tablishment of lactobacilli in the digestive tractof germ frees chickens.Jap. J. Microbiol., 15:531-37.

Morishita, T. Y., R. Fuller and M. K. Coates,1982. Influence of dietary lactose on the gutflora of chicks. Br. Poultry Sci., 23: 349- 59.

Morishita, T. Y., 2003. Ensuring Food Safety:Probiotics and other alternatives to antibiot-ics. Proceedings of Midwest Poultry Federa-tion Convention, St. Paul, Minnesota, 18th-20th

March, USA, pp. 21-24.Morissette, C., J. Goulet, and R., Letarte, 1991.

Effet l’une alimentation enrichie en fermentslactiques sur l”unmunite humorale de la souriset sa survie a une dose letale de Klebsiellapneumoniae. Can. Inst. Sci. Technol. J., 24:1-2.

Morotomi, M., 1996. Properties of Lactobacilluscasei Shirota strain as probiotics. Asia Pac.J.Clin. Nutr., 5:29-30.

Mulder, R.W.A.W., R. Havenaar, and Huis in’tVeld, 1997. Intervention strategies: the use ofprobiotics and competitive exclusion microflo-ras against contamination with pathogens inpigs and poultry. In: Probiotics 2. Applica-tions and practical aspects (Ed.R. Fuller),Chapman & Hall, London, pp 187-207.

Muriana, P.M. and T. R. Klaenhammer, 1987.Conjugal transfer of plasmid-encoded determi-nants for bacteriocin production and immunityin Lactobacillus acidophilus 88. Appl. Environ.Microbiol., 53:553-560.

Murphy, M.G., and S. Condon, 1984. Correla-tion of oxygen utilization and hydrogen perox-ide accumulation with oxygen induced en-zymes in Lactobacillus plantarum cultures.Arch. Microbiol. 138:44-48.

Murray, H. W., 1988. Interferon-gamma, the acti-vated macrophage, and host defence againstmicrobial challenge. Ann. Int. Med. 108:595-608.

Myers, R. P., 1931. Transformation of the intesti-nal flora through feeding has unfermented aci-dophilus milk. Am. J. Publ. Health, 24:470.

Nakazawa, Y. and A. Hosono, 1992. Functionsof Fermented Milks. Challenges for the HealthSciences, Elsevier Applied Science, London andNew York, 518 pp.

Nes, I. F., D. B. Diep, L. S. Havarstein, M. B.Brurberg, U. Eijsink, and H. Holo, 1996.Biosynthesis of bacteriocins in lactic acidbacteria. Antonie van Leeuwenhoek,.70:113-128.

Nettles, C. G. and S. F. Barefoot, 1993. Bio-chemical and genetic characteristics of bacte-riocins of food-associated lactic acid bacteria.J. Food Prot., 56:338-356.

Niamsup, P., I. N. Sujaya, M. Tanaka, T. Sone,S. Hanada, Y. Kamagata, S. Lumyong, A.Assavanig, K. Asano, F. Tomita, and A.Yokota,2003. Lactobacillus thermotolerans sp.

S. A. Denev106

nov., a novel thermotolerant species isolatedfrom chicken faeces. Int. J. Syst. Evol.Microbiol., 53:263-268.

Nishioka, K., T. Miyamoto, K. Kataoka, and T.Nakae, 1989.Preliminary studies on antimu-tagenic activities of lactic acid bacteria. Jap. LZootechn. Science, 60: 491-494.

Norat, T., and E. Riboli, 2003. Dairy Productsand colorectal cancer. A review of possiblemechanisms and epidemiological evidence. Eur.J. Clin. Nutr., 57:1-17.

Nurmi, E. and M. Rantala, 1973. New aspects ofSalmonella infection in broiler production.Nature, 241:210-211.

Ohashi, T., Y. Minamishima, T. Yokokura, andM. Mutai, 1989. Induction of resistance in miceagainst muriae cytomegalovirus by cellular com-ponents of Lactobacillus casei. Biotherapy,1:89-95.

Orrhage K., E. Sillerstrom, J. A. Gustafsson,C. E. Nord and J. Rafter 1994. Binding ofmutagenic heterocyclic amines by intestinaland lactic acid bacteria. Mutat. Res., 311:239-248.

Ouwehand A., P. Conway 1996 Specificity ofspent culture fluids of Lactobacillus ssp. Toinhibit adhesion of enteropathogenic fimbriatedE.coli cells. Microb. Ecol. Health. Dis., 9:239-246.

Ouwehand A., 1998. Antimicrobial componentsfrom lactic acid bacteria. In: Salminen S. andVon Wright Eds. Lactic acid bacteria:microboilogy and functional aspects. 2-nd ed.New York: Marcel Dekker Inc. 139-160 pp.

Pascual, M., M. Hugas, J. I. Badiola, J. M.Monfort, and M. Garriga, 1999. Lactobacil-lus salivarius CTC2197 prevents Salmonellaenteritidis colonization in chickens. Appl.Environ. Microbiol,. 65:4981-4986.

Pedersen, K. and G. W. Tannock, 1989. Coloni-zation of the porcine gastrointestinal tract byLactobacilli, Appl. Environ. Microbiol., 2:279-83.

Pedrosa, M. C., B. Golner, B. Goldin, S.Baraket, G. Dallal, and R. M. Russel, 1990.Effect of Lactobacillus acidophilus of yogurtfeeding on bacterial fecal enzymes in the eld-erly. Gastroenterology, 98, A439.

Pekkanen, J., S. Linn, G. Heiss, C. M.Suchindran, A. Leon, B. M. Rifkind, and H.A. Tyroler, 1990. Ten years mortality fromcardiovascular disease in relation to cholesterollevel among men with and without preexistingcardiovascular disease. N. Engl. J. Med.,322:1700-1710.

Percy-Robb, I. W. and J. G. Collee, 1972. Bileacids: a pH dependent antibacterial system inthe gut. Br. Med. J., 789:813-815.

Perdigon, G., M. E. Nader de Macias, S.Alvarez, G. Oliver, and A. Pesee de RuizHolgado, 1986a. Effect of preorally adminis-tered lactobacilli on macrophage activation inmice.Infect.Immun., 3:404-410.

Perdigon, G., M. E. Nader de Macias, S. Alva-rez, G. Oliver, M. Media, and A. Pesce deRuiz Holgado, 1986b. Effect of mixture ofLactobacillus casei and Lactobacillusacidophilus administered orally on the immunesystem of mice. J. Food Prot., 49: 986-989.

Perdigon, G., M. K. Nader de Macias, S. Alva-rez, 1986c. Activadad imunopotenciadora debacterias lacticas admintradas por via oral. Suefecto beneficioso en diarreas infan-tiles.Medicina (Buenos Aires), 46:751-754.

Perdigon, G., M. E. Nader de Macias, S. Alva-rez, G. Oliver, and A. Pesce de RuizHolgado, 1987. Enhancement of immuneresponse in mice fed with Streptococcusthermophilus and Lactobacillus acidophilus. J.Dairy Sci,. 70:919-926.

Perdigon, G., S. Alvarez, M. K. Nader deMacias, A. Pesce de Ruiz Holgado, 1988a.Activadad adyuvante de bacterias lacticas:perspectivas para su uso en vacunas orales.Rev. Argentina Microbiol., 20:141-146.

Perdigon, G., M. E. Nader de Macias, S. Alva-rez, 1988b. Systemic augmentation of the im-mune response in mice by feeding fermentedmilks with Lactobacillus casei and Lactobacillusacidophilus. Immu-nology, 63:17-23.

Perdigon, G., S. Alvarez, M. E. Nader deMacias, M. K. Roux, and A. Pesce De RuizHolgado, 1990. The oral administration oflactis acid bacteria increases the mucosal intes-tinal immunity in response to enteropathogens.J. Food Prot., 53: 404-410.


Perdigon, G. and S. Alvarez, 1992. Probioticsand immune state. In: Probiotics, The Scien-tific Basis (Ed. Fuller, R.), Chapman 8r. Hall,London, pp. 145-180.

Perdigon, G., M. Medici, M. K. Bibas Bonet DeJorrat, M. Valverde De Sudeguer, A. PesceDe Ruiz Holgado, 1993. Immunomodulatingeffects of lactic acid bacteria on mucosal andhumoral immunity. Int. J. Immunother. 9:29-52.

Perdigon, G., G. Aguero, S. Alvarez, C.Gaudioso de Allori, and A. Pesce De RuizHolgado, 1995. Effect of viable Lactobacilluscasei feeding on the immu-nity of the mucosaeand intestinal microflora in mal-nourished mice.Milchwissenschaft, 50 (5):251-256.

Perdigon, G., S. Alvarez, M. Rachid, G. Aguero,and N. Gobbato, 1995. Immune system stimu-lation by probiotics. J. Dairy Sci ., 78:1597-1606.

Perdigon G., E. Vintini, S. Alvares, M. Medinaand M. Medici, 1999. Study of the possiblemechanisms involved in the mucosal immunesystem activation by lactic acid bacteria. J.Dairy Sci., 82:1108-1114.

Perdigon, G., R. Fuller and R. Raya, 2001. Lac-tic acid Bacteria and their effect on the immunesystem. Current Issues Intest. Microbiol., 2(1):27-42.

Piard, J. C. and M. J. Desmazeaud, 1992.Inhib-iting factors produced by lactic acid bacteria.2. Antibacterial substances and bacteriocins.Lait, 72:113-142.

Prins, R. A., 1996. Microbiele ecologie, VakgroepMicrobiologie, Biologisch Centrum, Haren, TheNetherlands, pp.1208.

Podolsky, D. K., 2002. Inflammatory bowel dis-ease. N. Engl. J. Med., 347:417-429.

Polonskaya, M. S., 1952. An antibiotic from Lac-tobacillus acidophilus. Mikrobiology, 21:303-310.

Pot, B., W. Ludwlg, K. Kersters, and K. H.Schleifer, 1994. Taxonomy of lactic acid bac-teria. In: Bacteriocins of Lactic Acid Bacteria:Genetics and Applications (Eds L. De Vuystand E.J. Vandanune), Chapman and Hall,Glasgow, UK, pp.13-89.

Pradham, A. and M. K. Majumdar, 1986. Me-tabolism of some drugs by intestinal lactoba-cilli and their toxicological considerations. ActaPharmacol. Toxicol, 58:11-15.

Rada, V. and K. Vorisek, 1996. Effect of OralDosing of Lactobacillus salivarius 51R on in-testinal flora in broiler chicks. Fifth Sympo-sium on Lactic Acid Bacteria, Genetics, Me-tabolism and Applications, (Abstracts),Veldhoven, The Netherlands, September 8/12,J3.

Rafii, F., W. Franklin, and C. K. Gerniglia, 1990.Azoreductase activity of anaerobic bacteriaisolated from human intestinal microflora. Appl.Environ. Microbiol., 56:2146-2148.

Rammelsberg, M., and F. Radler, 1990. Anti-bacterial polypeptides of Lactobacillus species.J. Appl. Bacteriol., 69:187-194.

Rammelsberg, M., K. Muller, and F. Radler,1990. Caseicin 80: purification and character-ization of a new bacteriocin from Lactobacilluscasei. Arch. Microbiol., 154: 249-252.

Ray, B. and M. Daeschel, 1992. Food Bio-pre-servatives of Microbial Origin, CRC Press,Boca Raton,FL 245 pp.

Reddy, B.S., C. Sharma, L. Darby, K. Laakso,and K. L. Wynder, 1980. Metabolic epidemi-ology of large bowel cancer: fecal mutagens inhigh and low risk populations for colon cancer.Apreliminary report, Mutat. Res., 72:511-516.

Reddy, G.V. and K. M. Shahani, 1971. Isolationof an antibiotic from Lactobacillus bulgaricus,J. Dairy Sci., 54:748.

Reddy, C.V., K. M. Shahani, and M.R. Banerjee,1973. Inhibitory effect of yogurt on Ehrlichascites tumor-cell proliferation. J. Natl. Can-cer Inst., 50:815-817.

Reddy, G.V., B. A. Friend, K. M. Shahani, andR. E.Farmer, 1983. Antitumor activity of yo-ghurt components. J. Food Prot., 46: 8-11.

Reddy, G.V. and K. M. Shahani, 1984. Naturalantibiotic activity of Lactobacillus acidophilusand bulgaricus. III. Production and partial pu-rification of Bulgarican from Lactobacillusbulgaricus, Cult. Dairy Prod. J,. 19(2):7-14.

Reiter, B., V. M. Marshall, and S. M. Philips,1980. The antibiotic activity of the lactoper-

S. A. Denev108

oxidase-thiocyanate-hydrogen peroxide systemin the calf abomasum. Res. Vet. Sci., 28:116-122.

Reiter, B. and G. Harnulv, 1984. Lactoperoxi-dase antibacterial system: natural occurrence,biological functions and practical applications.J. Food Prot. 47:724-732.

Renner, H. W. and R. Munzer, 1991. The pos-sible role of probiotics as dietary antimutagens.Mutat. Res. 331:111-133.

Renner, E., 1994. Lactic acid bacteria in humannutrition. Actes du Colloque LACTIS 94, Eds.Nobel, G. A Le Querler, Jean-Francois) Caen,7-9 September, 1994, Presses universitaires deCaen, Gedex, France, pp. 193-199.

Renoit, R., R. Mathis, and G. Lefebvre, 1994.Characterization of Brevicin 27, a bacteriocinsynthesized by Lactobacillus brevis SB27.Current Microbiol., 28:53-61.

Rettger, L.G., M.N. Levy, L. Weinstein, and J.K. Weiss, 1935. Lactobacillus acidophilus andits Therapeutic Applications. Yale UniversityPress, New Haven, CT.

Reuter, G., 1965. Untersuchungen uber die Zu-sammensetzung und die Beeinflussbarkeit dermenschlichen Magen- und Darmflora unter be-sonderer Berucksichtigung der Lactobazillen,Ernahrungsforschung, 10: 429- 35.

Reuter, G., 1975. Position of the microflora ofhuman small intestine and the behaviour ofsome microorganisms after oral intake, Proc.IAMS, Tokyo. pp. 24

Roach, S., D.C. Savage, and G.W., Tannock,1977. Lactobacilli isolated from the stomachof conventional mice. Appl.Environ. Microbiol.,33:1197-203.

Rogers, L. A., 1928. The inhibitory effect of Strep-tococcus lactis on Lactobacillus bulgaricus. J.Bacteriol , 16:321-325.

Rolfe, R. D., 1991. Population dynamics of theintestinal tract. In: Colonization Control of Hu-man Bacterial Enteropathogens in Poultry (Ed.L.C.Blankenship), Academic Press, Ins., SanDiego, CA, pp-59-75.

Roos, N.M., and M. B. Katan, 2000. Effects ofprobiotic bacteria on diarrhea, lipid metabo-lism, and carcinogenesis: a review. Am. J. Clin.Nutr. 71:405-411.

Roos, S., L. Engstrand, and H. Jonsson, 2005.Lactobacillus gastricus sp. nov., Lactobacillusantri sp. nov., Lactobacillus kalixensis sp. nov.and Lactobacillus ultunensis sp. nov., isolatedfrom human stomach mucosa. Int. J. Syst. Evol.Microbiol., 55(1): 77-82.

Rowland, I. R., and P. Grasso, 1975. Degrada-tion of N-nitrosamine by intestinal bacteria.Appl. Microbiol., 29:7-11.

Rowland, I. R., A. K. Mallett, and A. Wise, 1985.The effect of diet on the manunalian gut floraand its metabolic activities. C.R C. Critical Rev.Toxicol., 16:31-103.

Russell, E. G., 1979. Types and distribution ofanaerobic bacteria in the large intestine of pigs.Appl. Environ. Microbiol., 37: 187-193

Salminen, S., I. Elomaa, J. Minkkinen, H.Vapaatalo, and S. Salminen, 1988. Preser-vation of intestinal integrity during radiotherapyusing live L. acidophilus cultures. Clin. Radiol,.39:435-437.

Salminen, S., M. Deighton, and S. Gorbach,1993. Lactic Acid Bacteria in Health and Dis-ease. In: Lactic Acid Bacteria (Eds. S. Salminenand A. von Wright). Marcel Dekker, Inc. NewYork, pp. 199-225.

Salminen, S., E. Isolauri, and K. Salminen,1996.Clinical uses of probiotics for stabilizingthe gut mucosal barrier: successful strains andfuture challenges. Antonie van Leewenhoek, 70:347-58.

Sandholm, T. M., and M. Saarela, 2003. Func-tional Dairy Products. Woodhead PublishingLimited, Cambridge, England, pp 395.

Sandine, W. E., K. S. Muralidhara, P. R. Elliker,and D. C. Ehgland, 1972. Lactic acid bacteriain food and health: a review with special refer-ence to enteropathogenic Escherichia coli aswell as certain enteric diseases and their treat-ment with antibiotics and lactobacilli. J. MilkFood Technol.,. 35: 691-702.

Sandine, W. E., 1979. Roles of Lactobacilli in theintestinal tract. J. Food Prot., 42: 259-262.

Sara, P.G., F. Dellaglio, and V. Bottazzi, 1985.Taxonomy of lactobacilli isolated from the ali-mentary tract of chickens. Syst. Appl.Microbiol., 6: 86-89.

Sato, K., 1984. Enhancement of host resistance


against Listeria infection by Lactobacilluscasei: Role of macrophages. Infect. Immun.44:445-451.

Sato, K., Saito, H. and H. Tomioka, 1988a. En-hancement of host resistance against Listeriainfection by Lactobacillus casei: Activation ofliver macrophages and peritoneal macrophagesby Lactobacillus casei. Microbiol. Immunol.,32:689-698.

Sato, K., H. Safto, H. Tomioka, and T.Yokokura, 1988b. Enhancement of host resis-tance against Listeria infection by Lactobacil-lus casei: Efficacy of cell wall preparation ofLactobacillus casei. Microbiol. Immunol.,32:1189-1200.

Satokari, R. M., E. E. Vaughan, H. Smidt, M.Saarela, J. Matto, and W. M. de Vos. 2003.Molecular approaches for the detection andidentification of bifidobacteria and lactobacilliin the human gastrointestinal tract. Syst. Appl.Microbiol., 26:572-584.

Savage, D. C., 1975. Indigenous microorganismsassociating with mucosal epithelia in thegastrointestinal ecosystem. In: Microbiology-1975, (Ed. D. Schlessinger), and American So-ciety for Microbiology, Washington, pp.120-123.

Savage, D. C., 1977. Microbial ecology of thegastrointestinal tract. Annual Rev. Microbiol.,31:107-33.

Savage, D. C., 1984. Present view of the normalflora. In: The Germfree Animals in BiomedicalResearch, (Eds. M.E. Coates and B.E.Gustafsson), Lab. Animals Ltd., London, pp.119-40.

Savage, D. C., 2001. Microbial Biota of the Hu-man Intestine: A tribute to Some PioneeringScientists. Curr.Issues Intest. Microbiol.,2(1):1-15.

Scheline, H. A., 1972. Metabolism of xenobiotiesby strains of intestinal bacteria. Acta Pharmacol.Toxicol., 31:471-480.

Schneitz, C., I. Nuotio and K. Lounatma, 1993.Adhesion of Lactobacillus acidophilus to avianintestinal epithelial cells mediated by the crys-talline bacterial cell surface layer (S- layer).J.Appl. Bacteriol., 74:290-294.

Sedewitx, S., K. H. Schleifer, and F. Gotz, 1983.

Purification and properties of pyruvate oxydasefrom Lactobacillus plantarum. In: Lactic acidbacteria in foods. Proc. Neth. Soc. Microbiol.Mtg., September 2-5, Wageningen, The Neth-erlands, pp. 33-37.

Seddon, S., 1989. The ecology of the gastrointes-tinal tract. In: Fermented Milks and Health.Proceedings of a workshop held on September26-26, Arnhem, The Netherlands, pp 3-12.

Sellars, R. L., 1992. Acidophilus products. InTherapeutic Properties of Fermented Milks(Ed. R.K Robinson.), Elsevier, London, pp. 81.

Shah N. P., 2001. Functional Foods fromProbiotics and Prebiotics. Food Technol.,55(11): 46-53.

Shahani, K. M., J. R. Vakil, and A. Kilara, 1976.Natural Antibiotic Activity of Lactobacillusacidophilus and bulgaricus. Cult. Dairy Prod.J,. 11(4):14-17.

Shahani, K. M., J. R. Vakil, and A. Kilara, 1977.Natural Antibiotic Activity of Lactobacillusacidophilus and bulgaricus. II. Isolation ofacidophilin from Lactobacillus acidophilusCult. Dairy Prod. J. 12(2):8-11.

Shahani, K.M. and A. D. Ayebo, 1980. Role ofdietary lactobacilli in gastrointestinalmicroecology. Am. J. Clin. Nutr., 33: 2448-2457.

Shahani, K. M., B. A. Friend, and P. J. Bailey,1983. Antitumor activity of fermented colos-trum and milk. J. Food Prot., 46:385-386.

Sharpe, M. E., M. J. Latham, K. I. GarvieZirngibl J., and O. Kandler 1973. Two newspecies of Lactobacillus isolated from the bo-vine rumen, Lactobacillus ruminis sp. nov. andLactobacillus vitulinus sp. nov. J. Gen.Microbiol., 77: 37-49.

Sharpe, M. E., 1981. The Genus Lactobacillus.In: The Procaryotes-A Handbook on Habitats,Isolation, and Identification of Bacteria (Eds.M.P. Starr, H. Stolp, H.G. Truper, A.Balows,H.G. Schlegel), Vol. II, Springer-Verlag,Berlin, Heidelberg, New York, pp.1653-1679.

Shimada, K., K. S. Bricknell, and S. M.Finegold, 1969. Deconjugation of bile acidsby intestinal bacteria: Review of the literatureand additional studies. J. Infect. Dis., 119:273-281.

S. A. Denev110

Shimuzu, T., K. Nomoto, T. Yokokawa, and M.Mutai, 1987. Role of colonystimulating activ-ity in antitumor activity of Lactobacillus caseiin mice. J. Leukocyte Biol., 42:204-212.

Shinoda, T., D. Kusuda, Y. Ishida, N. Ikeda, K.Kaneko, O. Masuda, and N. Yamamoto,2001. Survival of Lactobacillus helveticus strainCP53 in the human gastrointestinal tract. Let-ters in Applied Microbiology, 32:108-113.

Singh, B., R. P. Sinha, and R. N. Sinha, 1995.Isolation and biochemical characterization ofbacteriocin producing lactobacilli of gastrointes-tinal origin. Microbiol. Alim, Nutr., 13: 157-162.

Sleytr, U.B. and P.Messner, 1983. Crystallinesurface layers on bacteria. Ann. Rev. Microbiol.,37: 311-316.

Soerjadi, A. S., S. M. Stehman, G. H.Snoeyenbos, O. M. Wienack, and C. F.Smyser, 1981a. Some measurements of pro-tection against paratyphoid Salmonella and Es-cherichia coli by competitive exclusion inchickens. Avian Dis., 25:706-712.

Soerjadi, A. S., S. M. Stehman, G. H.Snoeyenbos, O. M. Wienack, and C. F.Smyser, (1991b) The influence of Lactobacillion the competitive exclusion of paratyphoidSalmonellae in chickens. Avian Dis., 25:1027-1033.

Solis, P.B. and D. Lemonnier, 1991. Inductionof 2'-5' A synthetase activity and interferon inhumans by bacteria used in dairy products. Eur.Cytokine Net., 2:137-140.

Sotirov, L., S. Denev, V. Georgieva, 2000. Effectof Different Growth Promoters on Lysozymeand Complement Activity of Broiler Chicks.Bulg. J. Agric. Sci, .6:75-82.

Sotirov, L., S. Denev, I. Tsachev, M. Lalev, M.Oblakova, and Z. Profirova, 2001. Effect ofdifferent growth promoters on lysozyme andcomplement activity. II. Studing in turkeys.Revue Med. Vet., 152(1):67-70.

Spanhaak, S. R. Havenaar, and G. Schaafsma,1998. The effect of consumption of milk fer-mented by Lactobacillus casei strain Shirotaon the intestinal microflora and immune pa-rameters in humans. Eur. J. Clin. Nutr., 52:1-9.

Speck, M. L., 1976. Interactions among lactoba-cilli and man. J. Dairy Sci,. 59:338.

Stark, C.N., R. Gordon, J. C. Mauer, L. R.Curtis, and , J. H. Schubert1934. Studies onacidophilus milk. Am. J. Publ. Health, 24:470.

Stellwag, E. J. and, P. B. Hylemon, 1976. Purifi-cation and characterization of bile salt hydro-lase from Bacteroides fragilis subsp. fragilis.Biochem. Biophys. Acta, 452: 165-176.

Sudirman, F., F. Mathieu, M. Michel and G.Lefebvre, 1993. Detection and properties ofCurvaticin 13, a bacteriocin-lice substanceproduced by Lactobacillus curvatus SB13.Current Microbiol., 27:35-40.

Suegara, N., M. Morotomi, T. Watanabe, Y.Kawai, and M. Mutai, 1975. Behavior ofmicroflora in the rat stomach: Adhesion of lac-tobacilli to the keratinized epithelial cells ofthe rat stomach in vitro. Infect. Immun., 12:173-79.

Suzuki, Y., 1995. Effects of fermented milk onlipid metabolism. Snow Brand R&D Reports,105:67-108.

Tagg, J. R., A. S. Dajani, and L. W. Wannamaker,1976. Bacteriocins of gram-positive bacteria.Bacteriol. Rev., 40: 722-756.

Tahara, T., M. Oshimura, C. Umezawa, and KKanatani, 1996. Isolation, partial character-ization, and mode of action of Acidocin J1132,a two-component bacteriocin produced byLactobacillus acidophilus JCM 1132, Appl.Environ. Microbiol., 62: 892-897.

Takatoshi, I., T. Safto, Y. Kawai, and J. Uemura,1996. Bacteriocins of Lactobacillusacidophi-lus group lactic acid bacteria isolated from hu-man intestinal tract. FifthSymposium on Lac-tic Acid Bacteria. Genetics, Metabolism andApplication, Veldhoven, September 8/12, TheNetherlands, (Abstracts) C1.

Talarico, T. R., I. A. Casas, T. C. Chung, and W.J. Dobrogosz, 1988. Production and isolationof reuterin, a growth inhibitor produced byLactobacillus reuteri. Antimicrob. AgentsChemother., 32: 1854-1858.

Talarico, T. R. and W J. Dobrogosz, 1989. Chemi-cal characterization of an antimicrobial sub-stance produced by Lactobacillus reuteri.Antimicrob. Agents Che-mother., 33:674-679.

Tancrede, C.,1992. Role of human microflora inhealth and disease. Eur. J. Clin. Microbiol., In-


fect. Disease, 11:1012-1015Tannock, G. W., 1981. Microbial interference in

the gastrointestinal tract. Asean J. Clin. Sci., 2:2-34.

Tannock, G. W., O. Szylit, Y. Duval, and P.Raibaud, 1982. Colonization of tissue surfacesin the gastrointestinal tract of gnotobiotic ani-mals by lactobacillus strains. Can. J..Microbiol,.28: 1196- 98.

Tannock, G. W., 1984. Control of gasrointestinalpathogens by normal flora. In: Current Per-spectives in Microbial Ecology (Eds. M.J. Klugand C.A. Reddy), American Society for Mi-crobiology, Washington, USA, pp. 374- 82.

Tannock, G. W. and R. D. Archibald, 1984. Thederivation and use of mice which do not harbourlactobacilli in the gastrointestinal tract. Can. J.Microbiol., 30:849-53.

Tannock, G. W., 1988. The normal microflora: newconcepts in health promotion. Microbiol. Sci.,5: 4-8.

Tannock, G. W., 1988a. Mini Review: MolecularGenetics: A New Tool for Investigating theMicrobial Ecology of the GastrointestinalTract? Microbial Ecology, 15: 239-56.

Tannock, G. W., 1989. Biotin-labeled plasmidDNA probes for detection of epithelium-asso-ciated strains of lactobacilli. Appl. Environ.Microbiol., 2:461-464.

Tannock, G. W., M. P. Dashkevlcz and S. D.Feighner, 1989. Lactobacilli and bile salt hy-drolase in the murine intestinal tract. Appl.Environ. Microbiol., 55:1848-1851.

Tannock, G. W., 1990. The microecology of lacto-bacilli inhabiting the gastrointestinal tract. In:Advances in Microbial Ecology, Vol. 11, (Ed.K.S. Marshall.), New York, Plenum Press, pp.147- 171.

Tannock, G. W., R. Fuller and K. Pedersen,1990. A lactobacillus succession in the pigletdigestive tract demonstrated by plasmid pro-filing. Appl. Environ. Microbiol., 56:310-1316.

Tannock, G. W., 1992. The Lactic Microflora ofPigs, Mice and Rats. In: The Lactic Acid Bac-teria Vol.1., The Lactic Acid Bacteria in Healthand Disease (Ed. B.J.B. Wood), Elsevier Ap-plied Science, London and New York, pp.21- 48.

Tannock, G.W., A. Tangerman, A. Van Schaik,and M. A. McConnell, 1994. Deconjugationof bile acids by Lactobacilli in the mouse smallbowel. App. Environ. Microbiol., 60:3419-3420.

Tannock, G. W., 1995. Microecology of the gas-trointestinal tract in relation to lactic acid bac-teria. Int. Dairy J., 5(8):1059-1070.

Tannock, G.W., 2002. Probiotics and Prebiotics:Where are we going? (G. W. Tannock Ed.)Caister Academic Press, USA, pp. 336.

Tannock, G.W., 2004.A Special Fondness for Lac-tobacilli. Appl.Environ. Microbiol.70 (6): 3189-3194.

Ten Brink, B., J. H. J. Huis in’t velt, A. M.Minekus, 1990. Antimicrobial activity of Lac-tobacillus M 46: optimization of productionand partial characterization. FEMS Microbiol.Rev, 87:91.

Ten Brink, B. and H. Holo, 1996. Salivaricin B,an indictable bacteriocin produced by Lacto-bacillus salivarius M7. Fifth Symposium onLactic Acid Bacteria. Genetics, Metabolism andApplication, September 8/12, Veldhoven, TheNetherlands, (Abstracts) C1S.

Thanaruttikannont, T. and S. Rengpipat, 1996.Use of Lactobacillus spp. as probiotic supple-ment in chicken feed. Fifth Symposium on Lac-tic Acid Bacteria. Genetics, Metabolism andApplication, Veldhoven, September 8/12, TheNetherlands, (Abstracts), J43.

Thyagaraga, N., H. Otani, and A. Hosono, 1992.Studies on microbiological changes during thefermentation of “Idly”. Lebensm.-Wiss. uTechnol., 25:77-79.

Thyagaraga, N. and A. Hosono, 1993. Anti-mu-tagenicity of lactic acid bacteria from “Idly”against food-related mutagens. J. Food Prot.,56:1061-1066.

Thyagaraga, N. and A. Hosono, 1994. Bindingproperties of lactic acid bacteria from “Idly”towards food-borne mutagens. Food Chem.Toxic., 32(9):805-809.

Thomas, T. D. and G.G. Pritchard, 1987. Pro-teolytic enzymes of dairy starter cultures.FEMS Microbiol. Rev., 46: 245-268.

Toba, T., K. Yoshioka, and T. Itoh, 1991.Acidophilucin A, a new heat-labile bacteriocinproduced by Lactobacillus acidophilus IA.PI’

S. A. Denev112

1060. Lett. Appl. Microbiol., 12:106-108.Toba, T., K. Yoshfoka, and T. Itoh, 1991a. Poten-

tial of Lactobacillus gasseri isolated from in-fant faeces to produce bacteriocin. Lett. Appl.Microbiol., 12:228-231.

Toba, T., S. K. Samant, K. Yoshioka, and T.Itoh, 1991b. Reuterin 6, a new bacteriocin pro-duced by Lactobacillus reuteri LA 6. Lett. Appl.Microbiol., 13:281-286.

Tonila, I. T., 1996. Symbalance-start of a new yo-ghurt generation. Alimenta 35:29-30.

Tramer, J., 1966.Inhibitory effect of Lactobacil-lus acidophilus. Nature, 21:204-205.

Tuomola E., and S. Salminen, 1998. Adhesionof some probiotic and dairy Lactobacillusstrains to Caco-2 cell cultures. InternationalJournal of Food Microbiology, 41:45-51.

Tuomola E., R. Crittenden, M. Playne, E.Isolauri, and S. Salminen, 2001.Quality as-surance criteria for probiotic bacteria. Am. J.Clin. Nutr. (Suppl) 73: 393S-398S.

Turjman, N., G. Guidry, B. Jaeger, A.Mendeloff, and B. Calkins, 1982. Fecal bileacids and neutral steroids among Sevenih DayAdventists and the general population in Cali-fornia. In: Colon and Nutrition (Eds. Kaspar,W. and Goebell,H.), Lancaster. MTP Press,Hingham, MA.

Vakil, J. R. and K. M. Shahani, 1965. Partialpurification of antibacterial activity of Lacto-bacillus acidophilus. Bacteriol. Proc., 45:9.

Van der Vossen, J., H. Rahaoui, R. J. Leer, andB. T. Brink, 1996. The anticlostridial bacte-riocin Plantacin F and Acidocin B showsome degree of structural and functional simi-larity. Fifth Symposium on Lactic Acid Bacte-ria. Genetics Metabolism and Application,Veldhoven, September 8/12, The Netherlands,Abstracts, C20.

Van Tassell, R. L., D. K. MacDonald, and T. D.Wilkins, 1982a. Stimulation of mutagen pro-duction in human feces by bile acids. Mutat.Res., 103:233-238.

Van Tassell, R. L., D. K. MacDonald, and T. D.Wilkins, 1982b. Production of fecal mutagensby Bacteroides sp. Infect. Immunol., 37:975-979.

Varnam, A., 2002. Lactobacillus: occurrence and

significance in non-dayry foods. MicrobiologyToday, 29:13-17.

Venema, G., Huis In’t Veld and J. Hugenholtz,1996. Lactic Acid Bacteria: Genetics, Metabo-lism and Applications. Proceedings Fifth Sym-posium held in Veldhoven, The Netherlands,8-12 September, Kluwer Academic Publishers,Dordrecht, The Netherlands, 262 pp.

Vincent, J. G., R. C. Veomett, and R.F. Riley,1959. Antibacterial activity associated withLactobacillus acidophilus. J. Bacteriol.,178:477-484.

Wada, K. and K. Hayakawa, 1990. Biomedicaleffects of lactic acid bacteria. J. .Microorgan-isms, 6:44-55.

Wager, O.A., 1948. 0n the capacity of thermo-philic bacterial strains to form antibiotic sub-stance. Ann. Med. .Exp. Biol., 26: 119-125.

Walker, D. K. and S.K. Gilliland, 1993. Rela-tionship among bile tolerance, bile saltdeconjugation and assimilation of cholesterolby Lactobacillus acidophilus. J. Dairy Sci.,76:956-960.

Watkins, B. A., B. F. Miller, D. H. Neil, and M.T. Collins, 1979. In vivo inhibitory effects ofL. acidophilus against the pathogenic E. coli ingnotobiotic chicks. Poultry Sci, 58:1121.

Watkins, B. A., B. F. Miller, and D.H. Neil, 1982.In vivo inhibitory effects of L. acidophilusagainst the pathogenic E. coli in gnotobioticchecks. Poultry Sci., 61:1298-1308.

Watkins, B. A. and B. F. Miller, 1983a. Com-petitive gut exclusion of avian pathogens byLactobacillus acidophilus in gnotobiotic chicks.Poultry Sci., 62:1772-1779.

Watkins, B. A., and B. F. Miller, 1983b. Coloni-zation of Lactobacillus acidophilus in gnotobi-otic chicks. Poultry Sci., 58: 2152-2157.

Wesney, K., and G.W. Tannock, 1979. Associa-tion of rat, pig and fowl biotypes of lactoba-cilli with the stomach of gnotobiotic mice. Mi-crobial Ecology, 5: 35-42.

West, C. and Warner, P. J., 1988. Plantacin 8, abacteriocin produced by Lactobacillus planta-rum NCDO 1193. FEMS Microbiol. Lett., 49:163-165.

Wheater, D. M., A. Hirsch, and A.T. Mattick,1951. Lactobacillin, an antibiotic from lactoba-cilli. Nature, 168:659.


Wheater, D. M., A. Hirsch, and A. T. Mattick,1952. Possible identity of Lactobacillin withhydrogen peroxide produced by lactobacilli.Nature, 170:623-624.

Whitehead, H. R., 1933. A substance inhibitingbacterial growth produced by certain strains oflactic streptococci. Biochem. J,. 27:1793-1800.

Whitting, G. C., and J. G. Carr, 1959. Metabo-lism of cinnomic acid and hydroxycinnomicacids by Lactobacillus pastroranius var.quinicus, Nature, 184:1427-1428.

Wilkins, T. D., and R. L. Van Tessell, 1983.Production of Intestinal Mutagens. In: HumanIntestinal Microflora in Health and Diseases.(Ed. D.J. Hentges), Academic Press, New York,pp. 265.

Wilkins, T. D., M. Lederman, and R. L. VanTessell, 1981. Isolation of a mutagen producedin the human colon by bacterial action. In:Banbury Report, Vol. 7, Gastrointestinal Can-cer Exogenous Factors, Eds. Bruce, W.R.,Correa, P., Lipkins,M., Tannenbaud, S.R. andWilkins, T.D.),Cold Spring Harbor Laboratory,Cold Spring Harbor, NY, pp. 205.

Winitz, M., R. F. Adams, D. A. Seedman, P. N.Davis, L. C. Jayko, and J. A. Hamilton,1970. Studies in metabolic nutrition employ-ing chemically defined diets. II. Effects on gutmicroflora population. Am. J. Clin. Nutr.,23:254-258.

Wollowski, I., G. Rechkemmer, and P. Pool-Zobel, 2001. Protective role of probiotics andprebiotics in colon cancer. Am. J. Clin. Nutr.,73 (Suppl.): 451-455.

Wong, H. C., and Y. L. Chen, 1988. Effects oflactic acid bacteria and organic acids on growthand germination of Bacillus cereus. Appl.Environ. Microbiol. 54:2179-2184.

Wood, B. J. B., 1992. The Lactic Acid BacteriaVol.1., The Lactic Acid Bacteria in Health andDisease, Elsevier Applied Science, London andNew York, 485 pp.

Worthington, J. M., and R. S. Fulghum, 1988.

Cecal and fecal bacterial flora of the Mongoliangerbil and the chinchilla. Appl. Environ.Microbiol., 54: 1210-1215.

Yamamoto, T., Y. Kishida, T. Ishida, and M.Hanedano, 1986. Effect of lactic acid bacteriaon intestinally decomposed substance produc-ing bacteria of human source. Basics andClinic,s 20(14):123.

Yamashita, M., M. Fujisaka, E. Ohkushi, K.Kaihatsu, and S. Uchida, 1987. Ecologicalstudy on the effects of administration of threekinds of lactic acid bacteria on suppression ofintestinal decomposed substance. Clinics andMicroorganisms 13(b):87.

Yang, Z. 2000. Antimicrobial compounds and ex-tracellular polysaccharides produced by lacticacid bacteria: structures and properties. Aca-demic Dissertation. University of Helsinki, Fin-land, pp 61.

Yokokura, T., S. Nomoto, T. Shimuzu, T., andK. Nomoto, 1986. Enhancement of hemato-poetic response of mice by subcutaneous ad-ministration of Lactobacillus casei. Infect.Immun., 52:156-160.

Young, G. P., 1996. Prevention of colon cancer:role of short chain fatty acids produced by in-testinal flora. Asia Pac. J. Clin. Nutr., 5:44-47.

Yuguchi, H., T. Goto, and S. Okonogi, 1992.Fermented milks, lactic drinks and intestinalmicroflora.In: Functions of Fermented Milks.Challenges for the Health Sciences. (Eds.Nakazawa Y. and Hosono A.), Elsevier Ap-plied Science, London and New York, pp.247-273.

Zachariah, P.K., and M. R. Juchau, 1974. Therole of gut flora in the reduction of aromaticnitro groups. Drug Metab. Dispos., 2:74-77.

Ziprin, R. L., M. H. Elissalde, A. Hinton, R.C.Beier, G. E. Spates, D. E., Corrier, T. G.Benoit, and J. R. DeLoach, 1991. Coloniza-tion control of lactose fermenting Salmonellatyphimurium in young broiler chichens by useof dietary lactose. Am. J. Vet. Res., 52:833-837.

S. A. Denev114

Received November, 10, 2005; accepted January, 8, 2006.

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