Part 2

EUKARYOTIC MICROBES

ALGAEPhotosynthetic eukaryotesSome algal cells have pellicle, a stigma and

flagellaSizes range from tiny, unicellular, microscopic to

large and multicellular.Found in freshwater, salt water, in wet soil or wet

rocks.Most are photoautotroph

(A)Vaucheria (B) Diatom (C)Navicula (D) Oocystis (E) Scenedesmus (F)Spirogyra (G) Nostoc (H)Oscillatoria

Phylum BacillariophytaDiatomsMicroscopic, unicellular,

live in both freshwater and salt water

Cell walls contain SiO2

Chlorophyll a and c, carotene, xanthophylls

Attractive, geometric and varied appearance

Phylum DinoflagellataDinoflagellatesMicroscopic, unicellular,

flagellated and often photosynthetic

Chlorophyll a and c, carotene, xanthins

Neurotoxins cause paralytic shellfish poisoning

Red Dinoflagellate

Phylum Chlorophyta

Green algaeCellulose cell wallsUnicellular or

multicellularChlorophyll a and bStore glucose

polymerGave rise to plants Spirogyra

Characteristics

Spirogyra- filamentous algaChlamydomonas- unicellular, biflagellated, one

chlorophyll and stigmaVolvox- multicellular alga, biflagellated cells

arranged to form a sphereDesmids- unicellular, resembles a banana

Chlamydomonas Volvox

Desmid

Phylum PhaeophytaBrown algaeCellulose + alginic acid

cell wallsMulticellularFew are microscopicChlorophyll a and c,

xanthophyllsStore carbohydratesHarvested for algin

AlgininAlginate absorbs water quickly, which makes it

useful as an additive in dehydrated products such as slimming aids, and in the manufacture of paper and textiles.

It is also used for waterproofing and fireproofing fabrics, as a gelling agent, for thickening drinks, ice cream and cosmetics, and as a detoxifier that can absorb poisonous metals from the blood.

Giant Kelp

Sargassum

Phylum RhodophytaRed algaeCellulose cell wallsMost multicellularChlorophyll a and d,

phycobiliproteinsStore glucose polymerHarvested for agar and

carrageenan

Agar Carrageenan

Agar is used to make jellies, puddings and custards.

Used throughout the world to provide a solid surface containing medium for the growth of bacteria and fungi.

Used for electrophoretic separation in agarose gel electrophoresis

Carrageenan sed in the food and other industries as thickening and stabilizing agents.

Desserts, ice cream, milk shakes, sweetened condensed milks, sauces.

Pharmaceuticals — used as an inactive excipient in pills/tablets

Porphyra Gibsmithia

Phylum ChrysophytaGolden algaeSome colorless, but the

vast majority are photosynthetic

Important in lakesFacultatively

heterotrophicChlorophyll c,

carotenoids and xanthophylls Synura

Licmophora Aulacoseira

Phylum EuglenophytaEuglenoidsPossessed both algae and

protozoan characteristicsContain stigma and

flagellumChlorophyll a as the primary

photosynthetic pigment and chlorophyll b and carotenoids

Remaining two-thirds are either facultatively or, like animals, fully heterotrophic

Euglena acus

Strombomonas Phacus elegans

Medical Significance

Prototheca – causes protothecosis, lives on soil. Can enter wounds on feetSmall subcutaneous lesion to crusty, warty-

looking lesion. Debilitating or fatal if enters the lymphatic system

Phycotoxins – secretion, poisonous to humans fish and other animals

Typical pond water ALGAE and PROTOZOA

A.Amoeba sp. B.Euglena sp.C.Stentor sp.D.Vorticella sp.E.Volvox sp.F.Paramecium sp.

PROTOZOA

Eukaryotic, unicellular, animal-like, and motile Feeding state is a trophozoiteSome produce cysts (dormant stage)Asexual reproduction by fission, budding, or

schizogonySexual reproduction by conjugation

No cell walls, pellicle serves for protectionContractile vacuole (in Amoeba and

Paramecium), pumps out waterSome are parasites, break down and absorb

host nutrientsPathogens – (malaria, giardiasis, African

Sleeping sickness and amebic dysenterySymbiotic relationship (in termites)

Ciliates

Move by ciliaComplex cellsBalantidium coli is

the only human parasite

Vorticella

Paramecium

Amoebae

Move by pseudopods,Phagocytosis

Like WBCsEntamoeba – dysentery

and extraintestinal abscesses

Acanthamoeba- eye infection

Entamoeba Acanthamoeba

Flagellates

Multiple flagellaGiardia lambliaTrichomonas

vaginalis (no cyst stage)

Trypanosoma Euglena

Sporozoa

No pseudopodia, flagella or cilia

Non-motilePlasmodium ssp.-

causes malariaCryptosporidium

parvum- cryptosporodiosis Plasmodium vivax

Plasmodium falciparum Cryptosporidium parvum

FUNGIEukaryotic, Kingdom FungiAerobic or facultatively anaerobic, found almost

everywhereSome are Saprophytic, others ParasiticMost are decomposers (organic matter/ leather

and plastics, spoilage of jams, pickles, etc.) some beneficial (prod’n cheese, wine, drugs: cyclosporine & penicillin)

Mycology is the study of fungi

Economic Effects of Fungi

Fungi Positive Effects Negative Effects

Saccharomyces Bread, wine, beer Food spoilage

Trichoderma Cellulose used for juices and fabric

Cryphonectria parasitica (chestnut blight)

Taxomyces Taxol production Ceratocystis ulm (Dutch elm disease)

Entomorphaga Gypsy moth control

Decomposers Versus Saprophyte

Decomposers- breaks material downSaprophyte (saprobe)- absorbs nutrients from

dead and decaying organic matterAll saprophytes are decomposers.Not all decomposers are saprophytes.Parasite obtain nutrients from living organisms.Saprophytes obtain nutrients from dead

organisms.

CharacteristicsNo chlorophyllCell wall contain chitinMany are unicellular (yeast)Others grow as filaments called hyphae, which

intertwine to form a mass called mycelia (thallus).

Some fungi have septate hyphaeOthers have aseptate hyphae, which contains

multinucleated cytoplasm (coenocytic).

Microscopic appearance of various Fungi

A.Aspergillus fumigatus B.Aspergillus flavusC.Penicillium sp.D.Curvularia sp.E. Scopulariopsis sp.F. Histoplasma capsulatum

ReproductionBudding, hyphal extension or formation of

spores.Fungal spores: sexual and asexual sporesSexual spores- fusion of two gametes

(ascospores, basidiospores, zygospores)Asexual spores- not formed by fusion (conidia)Some species can produce both sexual and

asexual sporesFungal spores are very resistant.

Fungal Life Cycle/ Reproduction

Conidiospores/ Conidia

Aspergillus flavus

Coccidioides immitis

Candida albicans

Classification

Divided into five phylaBased on their mode of reproductionLower fungi- Zygomycotina and

ChytridiomycotinaHigher fungi- Ascomycotina and

BasisiomycotinaFungi Imperfecti- Deuteromycotina

Classification According to Sexual ReproductionAccording to Sexual Reproduction

Lower fungi

Higher fungi

Fungi Imperfecti

YeastUnicellular fungiFission yeasts divide

symmetricallyBudding yeasts

divide asymmetricallyPseudohypha- string

of elongated budsChlamydosphores-

thick-walled spore-like

Yeasts

Left:Longitudinal sect. of a budding yeast; Right: Candida albicans A. Chlamydospores, B. Pseudohyphae, C.budding yeast cells Blastospores

Candida albicans Saccharomyces cerevisiae

Colonies of Candida albicans on blood agar plate

Molds

The fungi seen in water & food

Fungal thallus consists of hyphae; a mass of hyphae is a mycelium.

The Great Potato FaminePhytophthora infestans

– potato blight mold in Ireland

Killed Ireland’s potato crops in 1845, 1846 and 1848.

More than 1 million died of starvation

Antoine de Bary- proved that fungus caused the blight

Importance of MoldsAntibiotics from Penicillium and Cephalosporium.Many additional antibiotics discovered by isolating

molds that inhibit bacteria.Antibiotics can be chemically altered to increase

spectrum of activity ex.: Synthetic penicillins: ampicillin, amoxicillin, & barbenicillin

Some for production of large quantities of enzymes (amylase, citric acid, organic acids)

Molds provide flavor in diff. types of cheeses (, camembert, limburger).

Fleshy FungiLarge fungiMushroom, toadstools,

puffballs and bracket fungi

Many mushrooms are edible, but some are extremely toxic and may cause permanent liver and brain damage or death if ingested Amanita muscaria

Mushroom Toadstools

Puffballs Bracket fungi

Superficial mycoses Outermost areas (skin)Cutaneous mycoses Living layer of the skinOpportunistic mycoses Caused by normal

microbiota or fungi that are normally nonpathogenic

Subcutaneous mycoses Beneath the skinSystemic mycoses Deep within body

Fungal Infections (Mycoses)

Tinea pedis Oral thrush

Dimorphic FungiPathogenic dimorphic

fungi are yeastlike at 37°C and moldlike at 25°C

Histoplasma capsulatum (histoplasmosis)

Sporothrix schenckii (sporotrichosis)

Coccidioides immitis (coccidiomycosis)

Blastomyces dermatitidis (blastomycosis) Mycetomas

Teleomorphs and AnamorphsTeleomorphic fungi:

Produce sexual and asexual spores.Anamorphic fungi:

Produce asexual spores only.rRNA sequencing places most in Ascomycota, a few are

BasidiomycotaPenicilliumStachybotrys, Coccidioides, Pneumocystis (systemic

mycoses)Candida albicans (Cutaneous mycoses)

LichensMutualistic combination of an alga (or

cyanobacterium) & fungus – Symbiotic Alga produces and secretes carbohydrates,

fungus provides holdfastFound in various colors, black, brown, orange,

various shades of green, depending on combination of alga and fungus

Classified as protists

Fungus+Alga = LichensLichens

Slime MoldsFound in soil, rotting logsHave both fungal and protozoal chars. &

interesting life cyclesStart out in life as independent amoebaeSlug- motile, multicellular formSlug becomes a fruiting body (stalk and spore

cap)From each spores emerges and amoeba

Slime MoldsCellular slime molds

Resemble amoebas, ingest bacteria by phagocytosis

Cells aggregate into stalked fruiting body.

Some cells become spores

Plasmodial slime molds

• Multinucleated large cells

• Cytoplasm separates into stalked sporangia

• Nuclei undergo meiosis and form uninucleated haploid spores

Cellular Slime Mold

Plasmodial Slime Mold

Plasmodial Slime Mold- Fuligo septica

Lycogala epidendrum Hemitrichia calyculata

Arcyria cinerea Metatrichia vesparium

Quiz next meeting!!