Protista and Fungi Agents of Human Disease and Health

Features 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 Fungi 1. Zygomycetes bread mold Some orders can cause disease via inhalation of spores by immunocompromised individuals

Four Divisions of Fungi 2. Ascomycetes yeasts, mildews, morels, truffles Some types can cause a type of athletes foot

Four Divisions of Fungi 3. Basidiomycetes common mushrooms Cryptococcus can cause meningitis in immunocompromised individuals

Four Divisions of Fungi 4. Deuteromycetes Roquefort cheese, athlete’s foot

Ecological and economic importance 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 Protista Kingdom 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 Categories Grouped into three major, unofficial categories based on how they obtain nutrition 1.Protozoa - Animal-like Protists 2.Algae 3.Fungus-like Protists

Protozoans 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

Algae 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 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