MCB 100 1st Edition Lecture 36 Outline of Last Lecture I. Evolutionary history of eukaryotic microorganisms II. Ecology and distributionIII. Cell structure IV. Eukaryotic genes V. Reproduction Outline of Current Lecture I. Major groups of eukaryotic microorganisms a. Algaeb. Fungic. Protozoa (will cover next class) Current LectureI. Major groups of eukaryotic microorganisms a. Algaei. Most have cell walls composed of celluloseii. Photosyntheticiii. Both sexual and asexual reproductioniv. Most have mitochondriav. Most prefer aerobic conditions vi. Produce oxygen and fix carbon dioxidevii. Traits of the 6 major groups: 1. Euglenophytaa. Euglena b. No cell wallc. Thick flexible membrane called a pellicled. Flagella (kinetoplastids)2. Chlorophyta- green algaea. Cell walls are celluloseb. Chlorophylls are similar to plants- plantae2. Chrsophyta- diatomsa. Cell walls often contain glass-like silicates b. usually golden-brown color- stramenophila 2. Pyrrophyta- dinoflagellates a. 2 flagella These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Many produce toxins c. Cause "red tide"- a shell fish infection that can cause food poisoning- alveolates 2. Rhodophyta- red algaea. Sea weed, source of agar and carrageenan- rhodophyta2. Phaeophyta- brown algaea. Sea weed- stramenophila ii. Ecological significance of algae:1. Common in water, upper millimeters of damp soil, and in snow2. Oxygenic photosynthesis3. Bottom of food chain4. Some are involved in symbiotic relationships with fungi (lichens) b. Fungii. (myco-) ii. Cell walls made of chitiniii. Cytoplasmic membrane contains ergosteroliv. ~100,000 species v. Most fungi survive by degrading dead plant matter- can digest lignocellulose vi. Some are significant plant pathogens vii. Some, especially plant pathogens, produce potent toxins viii. Few are human pathogens ix. Have mitochondria (yeast petite mutants lack them)x. Most can reproduce either sexually or asexually xi. Unicellular fungi = yeasts xii. Multicellular fungi grow as filamentous hyphaexiii. Mycelium is a tangled mass or mat of hyphae xiv. Higher forms of fungi form complex fruiting bodies that produce sporesxv. Molds have relatively small fruiting bodiesxvi. Mushrooms, shelf fungi, and gill fungi have more elaborate fruiting bodies xvii. Fungal classification is based on sexual cycle and type of fruiting bodies i. Fungal spores1. Reproductive 2. Survive harsh conditions- drying, freezing, heat3. Molds and mushrooms make thousands of spores and scatter them in thewind as a way or reproducing and spreading 4. Can be of medical significance- people can become allergic to mold spores and fungal infections are often acquired from inhalation or contactwith spores 5. Can be either asexual vegetative spores that produced by mitosis or sexual spores that are produced in the diploid state or shortly after diploid cells undergo meiosis6. Sexual recombination involves fusion of 2 haploid cells to form a diploid cell and some time later meiosis to form haploid cells again7. Diploid stage may include cell growth and division- or may notii. Zymycota1. Zygomycetes are mostly molds such as Rhizopus and Mucor species 2. They reproduce asexually via sporangiospores3. Sexual cycle involves production of a mass of diploid cells called zygosporangium4. Meiosis within the zygosporangium yields haploid cells that form an asexual hypha and sporangium ii. Basidiomycetes1. Basidiospores develop at the end of club-shaped projections called basidia- which develop from the tightly woven intertwined hyphae of the basidocarp ii. Lichens1. Lichens- a community of microorganisms formed by a symbiotic partnership between a fungus and green algae or cyanobacteria i. Examples of fungi: (Some will be on exam 3!) 1. Saccharomyces cerevisiae (yeast)a. Used to make beer and raise breadb. Grows fastest in the presence of airc. Carries out alcoholic fermentation in absence of aird. CO2 makes bread rise and the bubbles in beer2. Candida albicans (yeast) a. Normal flora of human gut, mouth and other mucous membranesb. An overgrowth of yeast in the mouth causes thrush c. A yeast infection is an overgrowth of vaginal Candida d. Thrush in the throat is a sign of AIDS2. Penicillium chrysogenum (mold) a. Used to produce penicillinb. Grows fastest on glucose but produces antibiotic in stationary phase- when grown on lactose and limiting nitrogen 2. Phytophora infestans (water molds now classified with diatoms and brown algae in Stramenophila)a. Plant pathogen, there are many strains b. One strain caused Great Irish Potato blight- 1850s c. Another caused corn blight- 1973 2. Aspergillus flavus (mold) a. Ascomycota fungus, mold, conidia look like broccoli headsb. Causes a black smut on grains- peanuts, corn, rye, etc. c. Produces aflatoxin- a potent carcinogen d. Liver carcinogene. Appears in improperly stored grain and peanutsf. High doses cause acute hepatic necrosis- followed by cirrhosis or hepatocarcinoma g. Phobability of liver disease increases in people with hepatitis Bh. Aflatoxins convert guanines into thymines2. Claviceps purpurea AKA Ergot (mold)a. Causes a rust on rye and other grains b. Produces hallucinogenic compounds similar to LSD (can be used to induce labor, lower blood pressure, and ease migraines)1. Histoplasma capsulatuma. Spelunker's disease or Ohio Valley Feverb. A dimorphic fungus: hyphae in soilc. Yeast form in lung infectiond. May spread from lungs to other organs2. Coccidiodies immetisa. San Joaquin Valley Feverb. A dimorphic fungusc. Hyphae in soil d. Yeast form in lung infection2. Trichophyton rubruma. A cause of dermatophtosis b. Athlete's foot, ringworm 2. Penicillium italicuma. Grows on citrus2. Penicillium roquefortia. Used to make blue cheese2. Blastomyces dermatitidisa. Infects skin and/or lungs can cause a systematic disease called