Protista and FungiProtista and Fungi

Agents of Human Disease and Health

Features of fungiFeatures of fungi

• Eukaryotic and mostly multicellular

• Heterotrophic– digest food by secreting enzymes outside their

bodies, then absorb the digested nutrients

• reproduce sexually or asexually by spores

• decomposers help return nutrients to soil and air

Four Divisions of FungiFour Divisions of Fungi

1. Zygomycetes

• bread mold

• Some orders can

cause disease via

inhalation of spores by 

immunocompromised

individuals

Four Divisions of FungiFour Divisions of Fungi

2. Ascomycetes

• yeasts, mildews, morels, truffles

• Some types can cause a type of athletes foot

Four Divisions of FungiFour Divisions of Fungi

3. Basidiomycetes

• common mushrooms

• Cryptococcus can cause meningitis in immunocompromised individuals

Four Divisions of FungiFour Divisions of Fungi

4. Deuteromycetes

• Roquefort cheese, athlete’s foot

Ecological and economic Ecological and economic importance of fungiimportance of fungi

• mycorrhizae were important in plant evolution• lichens important in soil formation, indicator of acid rain or air

quality• antibiotics – penicillin created with ascomycetes• cyclosporine - immune suppresser useful to transplant patients•  Basidiomycota – decomposers that play a significant role in

the carbon cycle • Yeast necessary for bread production and are good genetic

engineering subjects

Kingdom ProtistaKingdom Protista

• mostly unicellular, some are multicellular (algae)

• can be heterotrophic or autotrophic

• most live in water (though some live in moist soil or even the human body)

• ALL are eukaryotic (have a nucleus)

• A protist is any organism that is not a plant, animal or fungus

3 Categories3 Categories

Grouped into three major, unofficial categories based on how they obtain nutrition

1.Protozoa - Animal-like Protists

2.Algae

3.Fungus-like Protists

ProtozoansProtozoans

Groups divided by type of locomotion • feed autotrophically as well as heterotrophically• most reproduce asexually

Zooflagellates - one or more flagella•Trypanosoma causes African sleeping sickness

Sarcodines - pseudopods

Ciliates – use cilia for feeding and movement

Sporozoans – parasites that do not move independently•Plasmodium causes malaria

AlgaeAlgae

•Photosynthesize but may become heterotophic in the absence of light•Live in fresh and salt water•Reproduce asexually

Euglenophytes – have two flagella but no cell wall

Chrysophytes – contain pectin instead of cellulose

Diatoms – cell walls are rich in silicon

Dinoflagellates – half photosynthesize, half heterotrophic–Gonyolax – toxin causing red tides which causes paralytic shellfish poisoning when is makes humans sick

•

Fungus Like ProtistsFungus Like Protists

• Heterotrophs that decay organic matter

• Have centrioles but lack chitin unlike true fungi

Slime Molds – recycle organic matter

Water Molds – live on dead matter in water; some are plant parasites on land

• Phytophthora infestans – type of water mold that caused the Irish potato famine between 1845 and 1851