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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

PowerPoint® Lecture Slide Presentation prepared by Christine L. Case

MicrobiologyB.E Pruitt & Jane J. Stein

AN INTRODUCTIONEIGHTH EDITION

TORTORA • FUNKE • CASE

Chapter 11The Prokaryotes:

Domains Bacteria and Archaea


The Prokaryotes: Domains Bacteria and Archaea• One circular chromosome, not in a membrane• No histones• No organelles• Peptidoglycan cell walls• Binary fission

Learning objective:

Make a dichotomous key to distinguish among the a-proteobacteria described in this chapter.


Bergey’s Manual

• Categorizes bacteria into taxa based upon rRNA sequences

• Lists identifying characteristics like: • Gram stain reaction• cellular morphology• oxygen requirements• nutritional properties

• Prokaryotes classified into two domains:• Bacteria• Archaea


• Bacteria essential to life on earth

• Proteobacteria• Mythical

Greek god, Proteus, who could assume many shapes

• Gram-negative

Domain Bacteria

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

• Human pathogens:• Bartonella• B. hensela Cat-scratch disease• Brucella Brucellosis

The α (alpha) Proteobacteria

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• Includes nitrogen-fixing bacteria, chemoautotrophs, and chemoheterotrophs

• Obligate intracellular parasites:• Ehrlichia. Tick-borne, ehrlichiosis• Rickettsia. Arthropod-borne, spotted fevers

• R. prowazekii Epidemic typhus• R. typhi Endemic murine typhus• R. rickettsii Rocky Mountain Spotted Fever




Figure 11.1


• Wolbachia. Live in insects and other animals

• In an infected pair, only female hosts can reproduce

• “Popcorn” strain causes host cells to lyse

• Possible biological control of insects



• Have prosthecae:• Caulobacter. Stalked

bacteria found in lakes

• Hyphomicrobium. Budding bacteria found in lakes


Figure 11.2 & 3


• Plant pathogen:• Agrobacterium.

Insert a plasmid into plant cells, inducing a tumor


Figure 9.17 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

• Chemoautotrophic:• Oxidize nitrogen for energy• Fix CO2

• Nitrobacter. NH3+ → NO2

–

• Nitrosomonas. NO2– → NO3

–


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• Nitrogen-fixing bacteria:• Azospirillum

• Grow in soil, using nutrients excreted by plants

• Fix nitrogen• Rhizobium

• Fix nitrogen in the roots of plants


Figure 27.5 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

• Produce acetic acid from ethyl alcohol:• Acetobacter• Gluconobacter



The β (beta) Proteobacteria

Learning objective:

Make a dichotomous key to distinguish among the β-proteobacteria described in this chapter.


• Thiobacillus• Chemoautotrophic, oxidize sulfur: H2S → SO4

2–

• Sphaerotilus• Chemoheterotophic, form sheaths


Figure 11.5

Sphaerotilus natans:

•Sheathed bacteria found in dilute sewage and aquatic environs


• Spirillum volutans:• Chemoheterotrophic,

helical• Note polar flagella

• Neisseria• Chemoheterotrophic,

cocci• N. meningitidis• N. gonorrhoeae (diplo-

cocci) – fimbriae attach to mucous membranes for greater pathogenicity


Figure 11.4 & 6

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• Bordetella• Chemoheterotrophic, rods• B. pertussis (pertussis or whooping cough)

• Burkholderia. Nosocomial infections (hospital infection)• Extraordinary nutritional spectrum, able to degrade

> 100 different organic molecules, can grow in disinfectant!

• Zoogloea. Slimy masses in aerobic sewage-treatment processes – essential to sewage treatment




The γ (gamma) Proteobacteria

Learning objective:

Make a dichotomous key to distinguish among the γ -proteobacteria described in this chapter.


• Pseudomonadales:• Pseudomonas

• Gram -• Opportunistic

pathogens• Metabolically

diverse• Polar flagella (characteristic, as in picture)

• Azotobacter and Azomonas. Nitrogen fixing• Moraxella. Conjunctivitis


Figure 11.7


• Legionellales:• Legionella

• Found in streams, warm-water pipes, cooling towers of air-conditioning

• L. pneumophilia (Legionnaire's)

• Coxiella• Q fever

transmitted via aerosols or milk


Figure 24.15b

Coxiella burnetii


• Vibrionales:• Found in coastal water

• Vibrio cholerae causes cholera

• Slight curvature of rods

• V. parahaemolyticuscauses gastroenteritis (raw/undercooked shellfish)


Figure 11.8

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• The γ (gamma) Proteobacteria• Enterobacteriales (enterics – intestinal tracts):

• Peritrichous flagella, facultatively anaerobic• Enterobacter• Erwinia• Escherichia• Klebsiella• Proteus• Salmonella• Serratia• Shigella• Yersinia




Figure 11.9a, b

Proteus mirabilis – swarmer due to multiple flagella


• Pasteurellales: • Non-motile• Human and animal pathogens• Pasteurella

• Cause pneumonia and septicemia• Haemophilus

• Require X factor (heme) and V factor (NAD+, NADP+) factors from blood hemoglobin

• H. influenzae – several important diseases (meningitis, earaches, epiglotitis, bronchitis, etc.)



• Beggiatoa• Chemoautotrophic, oxidize H2S to S0 for energy• Interface between aerobic and anaerobic layers in

aquatic sediments• Factor in discovery of of autotrophic metabolism

• Francisella• Chemoheterotrophic, tularemia



The δ (delta) Proteobacteria

Learning objective:

Make a dichotomous key to distinguish among the δ -proteobacteria described in this chapter.

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• Bdellovibrio. Prey on other bacteria• Desulfovibrionales. Use S instead of O2 as final

electron acceptor (sulfur reducing)• Releases tons of H2S into atmosphere, key part in

sulfur cycle• Myxococcales. Gliding. Cells aggregate to form

myxospores (stalked fruiting body – 2nd slide next)• Leave behind a slime trail (next slide)• Nutrition from bacteria they encounter




Figure 11.10a



Figure 11.1b Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

The ε (epsilon) Proteobacteria

Learning objective:

Make a dichotomous key to distinguish among the ε -proteobacteria described in this chapter.


The ε (epsilon) Proteobacteria

Figure 11.1a

• Helicobacter• Multiple flagella • Peptic ulcers• Stomach cancer

• Campylobacter• One polar flagellum• Gastroenteritis


Helicobacter pylori:

Example of a helical bacterium that doesn’t make a complete twist (different from spirochetes)

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The Nonproteobacteria Gram-Negative Bacteria

Learning objective:

Make a dichotomous key to distinguish among the gram-negative nonproteobacteria described in this chapter.


• Oxygenic photosynthesis • Once called blue-green algae• Water species have gas vacuoles for

buoyancy• Gliding motility• Fix nitrogen in heterocysts• Played important part in development of life

on earth, producing oxygen atmosphere

Cyanobacteria


Cyanobacteria

Figure 11.12a-c Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

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• Anoxygenic photosynthesis• Purple and green sulfur bacteria (bottom formula)

Purple and Green Photosynthetic Bacteria

2H2O + CO2light

(CH2O) + H2O + O2

2H2S + CO2light

(CH2O) + H2O + 2S0

Learning objective:

Compare and contrast purple and green photosynthetic bacteria with cyanobacteria


Purple sulfur bacteria: intracellular sulfur granules (multicolored refractile objects (anoxygenic photoautotrophs)


• Low G + C• Gram-positive

FirmicutesLearning objective:

Make a dichotomous key to distinguish among the low G + C gram-positivedescribed in this chapter.


• Clostridium• Endospore-

producing• Obligate anaerobes• Endospores usually

distend the cell wall• Epulopiscium

• Very large, shown on the head of a pin

• rRNA determined placement with prokaryotes

Clostridiales

Figure 11.14 & 15


• Bacillus• Endospore-producing

rods• B. anthracis - anthrax

Bacillales

Figure 11.16b Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

• Staphylococcus aureus• Cocci in grapelike clusters• Gram-positive, produces enterotoxin• Grow fairly well under high osmotic pressure

and low moisture (nasal secretions, skin, ham and other cured meats)

Bacillales

Figure 1.17

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• Generally aerotolerant anaerobes, lack an electron-transport chain• Lactobacillus – lactic-

acid producing• Streptococcus –

more illnesses and diseases than any other bacteria group

• Enterococcus –intestinal tract, oral cavity

• Listeria –contaminates dairy

Lactobacillales

Figure 11.18

Streptococcus – many of spherical cells are dividing and somewhat oval


• Mycoplasma pneumoniae• No cell walls• Pleomorphic (irregular

cells)• Arrows indicate terminal

structures that likely aid attachment to eukaryotic cells

• 0.1 - 0.24 µm

• Filamentous growth of M. pneumoniae• Reproduces by

fragmentation of the filaments

Mycoplasmatales

Figure 11.19a, b


• High G + C• Gram-positive

ActinobacteriaLearning objective:

Make a dichotomous key to distinguish among the high G + C gram-positivedescribed in this chapter.


• Actinomyces• Corynebacterium• Frankia• Gardnerella• Mycobacterium• Nocardia• Propionibacterium• Streptomyces

Actinobacteria

Figure 11.20b


• Streptomyces –• Filamentous

branching growth with asexual reproductive conidiospores at tips

• Make up much of soil bacteria

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsActinomyces – notice branched filamentous morphology

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• C. trachomatis• Trachoma• STD, urethritis

• C. pneumoniae• C. psittaci

• Causes psittacosis

Chlamydiae


Generalized life cycle of Chlamydia (48 hours)

Figure 11.22a


Generalized life cycle of Chlamydia

Figure 11.22b

Elementary bodies – infectious stage

Reticulate bodies – reproduce in host cell

Intermediate bodies – stage in between Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

• Borrelia• Leptospira• Treponema

Spirochaetes

Figure 11.23

Spirochetes –

•Helical, axial filaments under outer sheath

•Move by corkscrewlike rotation


• Anaerobic• Bacteroides. In mouth and large intestine• Cytophaga. Cellulose-degrading in soil

Phyla Bacteroidetes & Fusobacteria

• Fusobacterium• Found in mouth• May be involved in

dental diseases


• Hyperthermophiles (heat)• Pyrodictium• Sulfolobus

• Methanogens (methane)• Methanobacterium

• Extreme halophiles (salt)• Halobacterium

Domain Archaea

Figure 11.25

Archaea – Pyrodictium abyssi:

•Deep ocean, 110 degrees C

•Cells disk-shaped with network of tubules (cannulae)

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• Bacteria size range• Thiomargarita

(750 µm) to nanobacteria (0.02 µm) in rocks

Microbial Diversity

Figure 11.26

Thiomargarita namibiensis:

•Energy from reduced sulfur compounds


• Few of the total number of prokaryotes have been isolated and identified

• PCR indicates up to 10,000 bacteria/gm of soil. Many bacteria have not been identified or characterized because they:• Haven't been cultured• Need special nutrients• Are part of complex food chains requiring the

products of other bacteria• Need to be cultured to understand their metabolism

and ecological role

Microbial Diversity