PH 162A Lec 3 Microscopic Algae and Fungi

eukaryotic and have a cell wall

most are autotrophs via photosynthesis in chloroplasts and have different pigments depending on type of chlorophyll (red, green, yellow, or brown)
some are heterotraphs, require additional nutrients but can still photosynthesize, eg. euglena

sense and stigma move toward light to increase or enhance photosynthesis eg. euglena

1.) flagella
2.) gliding motion- secrete mucus substrate and glide on it

1.) cell wall made of cellulose
2.) cell walls with silica or calcium carbonate incorporated from their environment
3.) cysts- goes into resting state, protects from extreme environment
4.) pellicle- outer membraneous cover

1.) spore production- genetically identical, specialized to survive
2.) can fragment filament to create new individual as a result of these new fragments
3.) binary fission or multiple fission

gametogenesis
1.) isogamy- 2 gametes produced- same size and structure, motile or nonmotile (eg. sperm)
2.) heterogamy- 2 gametes produced- sperm and egg

1.) primary producers of O2- occurs in phytoplankton
2.) important part of food chain.
3.) diatomaceous earth

many organisms eat algae; kelp (brown-algae) enhance smoothness and spreadability to food

diatoms- top prdoucers of O2, freshwater and marine, no flagella, silicon, CaCO3 shell, diatomaceous earth, fossils of diatoms
dinoflagellates- marine environments, 2 flagella, some exhibit bioluminescence

1.) imparting unpleasant taste to drinking water eg. cyanobacteria
2.) fouling up swimming pools and swimming beaches
3.) various types of shellfish poisoning
4.) pathogenic algae

usually look, smell, taste, and normal; 4 diff dinoflagellates cause red tide which has high level of toxins--> shellfish uptake is increased and then humans eat it!

prototheca: mutant of green algae that has no chloroplasts so grows in humans, causes minor skin

1.) paralytic shellfish poisoning (saxitoxin/PSP)
2.) amnesic shellfish poisoning (domoic acid/ASP)
3.) diarrhetic toxic poison
4.) alaspiric acid

red-brown dinoflagellates --> red tides and saxitoxin concentrates within shellfish that eat them; 15 min-10 hour diarrhea; high doses--> paralysis/numbness/tingling; colder coastal waters of pacific and new england and central america

short term loss of memory, heat stable

1.) inspection of commercial shellfish farms- no easy test
2.) beach warnings
3.) thorough cooking- doesn't inactivate toxin

1.) yeasts
2.) molds
3.) dimorphic fungi

single-cell; repro asex via budding or binary fission or repro sex by conjugation
eg. Saccharomyces (wine), torulopsis, cryptococcus

-hyphae (septate- segmented = cell; aseptate)
-mycelium (lots of hyphae or long filaments)
-colony
-repro unit= spore

ability of an organism to alter its structure when it changes habitats: saprophytic and parasitic

the two forms of fungi:
saprophytic- free living in nature, room temp.
parasitic- yeast form in humans, body temp 37C

1.) Histoplasma capsulatum- causes histoplasmosis
2.) Coccidioides immitis- causes coccidioidomycosis
3.) Blastomyces dermatitidis- blastomycosis

Midwest esp. Kansas City; mild respiratory infection but can be life-threatening, associated with bat and bird guano, age 20 = 80-90%, had a positive skin test

Valley Fever; Central (San Joaquin) Valley of California, SW USA and NW Mexico.
Disease cycle: spore goes into animal, animal dies and decomposes in soil --> asexually reproduce --> airborne --> human exposure

sapro phase- found in NE US and African soil that contains organic debris: rotting wood, animal droppings, plant material, alnog rivers
parasitic phase- inhalation of conidia in soil causes lung disease and may become disseminated in the body

heterotrophs, structures for obtaining nutrition- vegetative mycelium and rhizoids that grab onto food substrates for nutrients (root-like)

1.) thick cell walls composed of chitin, peptidomannans
2.) capsules- around cell walls

sexual: involves fusion of haploid gametes in repro structures
asexual:
1.)budding- daughter cell grows out of mother cell with budding cell smaller
2.)special reproductive- units aerial mycelia
3.) binary fission

1.) conidia
2.) spores

1.) decomposers of garbage
2.) food manufacture eg. aspergillus makes miso, sake, rice vinegar
3.) drugs used for treatment of human disease
4.) manufacture of biological reagents
5.) experimental organisms for research

1.) antibiotics- Penicillium
2.) ergot- used to induce abortions or stop bleeding after childbirth

1.) food spoilage- mold
2.) nuisances- wood rot
3.) infectious diseases- mycoses
4.) allergy- eg. Stachybotanys chartarum
5.) poisonings

aflatoxin- peanut fungus
ergot- neurotropic activities--> hallucinations, convulsions