Presentation on theme: "Survey of eucaryotic microbes"— Presentation transcript:
1 Survey of eucaryotic microbes FungiAlgaeProtozoaParasitic helminths (worms)
2 Kingdom Fungi 100,000 species divided into 2 groups: macroscopic fungi (mushrooms, puffballs, gill fungi)microscopic fungi (molds, yeasts)majority are unicellular or colonial, a few have cellular specialization
3 Roles of fungi decomposers of dead plants and animals sources of antibioticsused in making foods & in genetic studiesadverse impact – food spoilage, mycoses, toxin production
4 microscopic fungi exist in 2 morphologies yeast – unicellular, round ovoid shape, asexual reproduction (budding or transverse division) – also can form pseudohyphaeFilamentous (“mold”) - hyphae – long filamentous fungi or molds; forms tangled mass=myceliumsome exist in either form – dimorphic – characteristic of pathogens
5 yeasts Reproduces by budding or transverse division (asexual) Can form pseudohyphae (chains)Some can also form spores (sexual repro)Example: Saccharomyces cerevisae (Brewer’s or baker’s yeast)
8 Fungal nutrition all are _________________ majority are harmless __________living off dead plants & animals (saprophytes)secrete hydrolytic enzymes, digest externallysome are parasites, living on the tissues of other organisms, but none are obligate; __________= fungal infectionsgrowth temperature 20o-40oCextremely widespread distribution, many habitats
9 Fungal Reproductionprimarily through __________formed on special reproductive __________asexual reproduction – spores are formed through budding (yeasts) or in __________or _______________________ (molds)sexual reproduction – spores are formed following fusion of male & female strains & formation of sexual structuresexual spores are one basis for __________
10 I. Asexual reproduction Molds - ReproductionTransverse fissionBuddingSpores (most common)Sporaniogpores – spores enclosed in head (sporangium) – sits atop stalk (___________________)Conidia – free spores
11 I. Asexual Reproduction SporangiosporesStalk =Sac =Spores =
12 Conidia All form on top of stalk (conidiophore) I. Asexual ReproductionConidiaAll form on top of stalk (conidiophore)Arthrospores – septate hypha – fragments break offChlamydospores – spherical, thickened hyphal cell Blastospore = budPhialospore – buds from vase shaped phialideMicro/macro conidium – small and large versions of conidia, 1 and 2+celled, respectively.Porospore – conidium that grows from poreYou do NOT have to memorize these types of conidia!
14 Spore types and representative genera I. Asexual ReproductionSpore types and representative generaSporangiospores – Absidia, MucorArthrospores – CoccidiodesChlamydospores/blastospores – Candida albicansPhialospores – Aspergillus, PenicilliumMicro/microconidia – Microsporum, FusariumPorospores - AlternariaYou do NOT have to memorize these types of conidia!
15 II. Sexual reproduction Involves fertilization – union of compatible nucleiSome can self-fertilizeCan yield spores:ZygosporeAscosporeBasidiospore
16 4 main divisions of molds based on sexual spore type II. Sexual Reproduction4 main divisions of molds based on sexual spore typeZygomycotaAscomycotaBasidiomycotaDeuteromycota – no sexual spores?
17 Zygomycota Ascomycota Basidiomycota Detueromycota Sexual spores None or not describedAsexual sporesSporangio-(some conidia)Types of conidiaConidiaVar. conidiaHyphaeNonseptate or complete septaPorous septateIncompletely septateseptateLifestyleMostly saprobes some parasitesMany important species and pathogensFleshy fruiting bodies; some plant parasites, 1 pathogenSome dimorphic; saprobes and some parasitesexamplesRhizopus, MucorAgents of dermatophytosis, Histoplasma, Penicillium, Saccharomyces, Pneumocystis cariniiCryptococcus neoformans; mushrooms, puffballs, rusts, smutsCoccidioides immitis, Candida albicans, Cladosporium, Strachybotrys
18 Fungal pathogenesis (mycosis) Most fungi are not true pathogens (they don’t attack healthy people)Most are ______________– invade those with compromised immune systems (AIDS, cancer, diabetes)Degree of mycosis (disease) varies by mode of infection and organs involvedFungi also cause ______________– , and produce ______________–
24 Case study: mucormycosis Mucor sp. – common mold of soil, bread, fruit etc.Opportunistic infectionMark Tatum – steroids suppressed his immune systemInhaled spores infection in sinusHad to have sinuses removed including nose, eyes and face
26 Benefits of fungi Decomposers of organic matter (recycle nutrients) Symbiosis with plant rootsProduce antibiotics, organic acids, vitaminsFermentation (alcohol)Foods – bread, cheese; also eaten as foods
27 Identifying Fungi Media – cornmeal, blood, Sabouraud’s agar ID by asexual stages (sexual not common in lab cultures)Also physical characteristics: hyphae, colony morphology, color, other characteristicsGenetic tests
29 Algae photosynthetic organisms contain chloroplasts with chlorophyll & other pigments; cell wall; may or may not have flagellakelps, seaweeds, euglenids, green algae, diatoms, dinoflagellates, brown algae, & red seaweedsmicroscopic forms are unicellular, colonial, filamentousmacroscopic forms are colonial and multicellularmost are free-living in fresh and marine water(you have seen examples off all of these in lab)
31 Algae classified according to types of pigments & cell wall provide basis of food web in most aquatic habitats (plankton)produce large proportion of atmospheric O2used for cosmetics, food & medical products_______________ cause red tides & produce toxins – paralytic shellfish poisoning
33 DinoflagellatesParalytic shellfish poisoning – accumulation of toxins in clams and other shellfishCiguatera – accumulation in fish - no antidote for toxin. Can be self-limiting._______________ _______________ (pfiesteriosis)– parasite of fish and humans; algal blooms from agricultural runoff; also has potent toxins