Ch 11 and 12 – Flashcards
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| Archea |
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| -membranes composed of branched hydrocarbon carbon chains attached to glycerol by ether linkages -no peptidoglycan -no sensitive to muramic acid or D-amino acids (antibiotics) -unique rRNA -extremophiles |
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| Sulfolobus |
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| -aerobic, irregularly lobed, spherical bacteria -thermoacidophiles -oxidize sulfur to sulfuric acid |
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| Thermoproteus |
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| -long thin bent or branched rods -strict anaerobes -temp optima 70-97 -PH optima 2.5 -6.5 -grow in hot springs and hot aquatic habitats containing sulfur |
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| methanogens |
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| -strict anaerobes that obtain energy by converting CO2, H2, formate, methanol, acetate to methane (and CO2 sometimes) -suggested earliest organisms -thrive in anaerobic environments rich in organic compounds -great potential importance |
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| Thermoplasma |
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| -no cell wall -found in coal mine refuse -optimum temp and pH 55-59 degrees C, 1-2pH |
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| Picrophilus |
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| -aerobic -grows between 47-65 deg C -only grows under 3.5 pH -optimum .7 |
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| mycology |
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| study of fungi |
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| 3 exmaples of fungi |
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| yeast, mold, fleshy |
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| fungi characteristics |
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| -eukaryotic -rigid cell wall -chemoheterotrophs (require organic compounds for both carbon and energy sources_ -obtain nutrients by absorption -obtain nutrients as saprophytes (live off decaying matter) or as parasites |
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| fungi are involved in... |
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| -animal/plant diseases -food spoilage -decomposition of organic material -recycling organic compounds in nature -production of antibiotics |
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| fungal cell wall |
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| -no peptidoglycan, teiochic acids, or polysacharrides -contain peptidomannan (mannose polymer antigenic to humans) -contain glucans (glucose polymers for strength) |
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| chitin |
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| -long unbranched chains of poly N acetyl glucosamine -structural support |
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| fungal plasma membrane |
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| -contains ergosterol -major target of antifungal drugs |
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| hyphae |
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| -basic morphological unit of all fungi -branching threadlike tubular filaments -septate -coenocytic |
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| septic hyphae |
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| -contains septa (cross walls) that divide them into distinct units with one nucleus |
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| conenocytic |
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| -long continuous cell with manu nucelei -no septa |
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| fungo elongate at... |
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| tips by extension |
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| vegetative hypha |
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| -portion that obtains nutrients |
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| reproductive/aerial hypha |
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| portion involved in reproduction |
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| mycelium |
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| mass of hypha |
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| yeasts |
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| -Unicellular -Usually appear as oval cells 1-5 ?m wide by 5-30 ?m long -typical eukaryotic structures -thick polysaccharide cell wall- -Facultative anaerobic -Reproduce asexually by budding or fission -S. cerevisiae -S. pombe |
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| dimorphic fungi |
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| -exist in mycelial or yeast morphology depending on environment -Candida albicans -Histoplasma capsulatum |
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| fungal reproduction |
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| 1. Budding 2. Fission 3. Hyphae fragmentation (tubular filaments) 4. Sporulation |
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| budding |
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| -uneven cytoplasmic division |
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| fission |
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| even cytoplasmic division |
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| hyphae fragmentation |
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| each part is capable of growth by elongating at tip |
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| sporulation |
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| -can be asexual or sexual -not same as bacterial spores |
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| asexual spores |
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| -conidiospores -sporangiospores |
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| conidiospores |
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| -unicellular or multicellular not enclosed in a sac -conidia are produced in a chain at the end -Aspergillus produces conidiospores -Candida albicans and Cryptococcus produce blastoconidia (buds coming off the parent cell) -Candida albicans also produces chlamydoconidia (thick-walled spore formed by rounding and enlargement within a hyphal segment |
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| sporangiospores |
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| -formed within a sac (sporangium) at the end of sporangiophore -can contain hundreds of sporangiophores -Rhizopus produces sporangiospores |
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| sexual spores phases |
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| -plasmogamy -karyogamy -meiosis |
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| plasmogamy |
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| Haploid nucleus of a donor cell (+) penetrates the cytoplasm of a recipient cell (-) |
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| karyogamy |
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| The donor (+) and recipient (-) nuclei fuse to form a diploid zygote nucleus |
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| meiosis |
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| The diploid nucleus gives rise to haploid nuclei (sexual spores) |
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| Zygomycota |
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| -asexual reproduction through sporangiospores -sexual reproduction through zygospores -cause serious infections particularly in diabetics and people with immune deficiency -zygomycosis is potentially lethal and can affect fetus -Rhizopus stolonifer, the common black bread mold |
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| Ascomycota |
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| -reproduce asexually through conidia -sexual reproduction results in ascospore occurs in ascus -Aspergillus flavus, which grows on peanuts generates aflatoxin, which damages the liver and is highly carcinogenic -Candida albicans, a yeast which attacks the mucous membranes, can cause an infection of the mouth or vagina called thrush, and is also blamed for "yeast allergies" |
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| Basidiomycota |
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| -includes fungi that produce mushrooms -most reproduce sexually by club shaped basidia that bear external basidiospores -Cryptococcus neoformans is the most prominent medically important species -causes meningitis and meningo-encephalitis in people with HIV/AIDS -There are about 37 recognized species of Cryptococcus, the majority living in the soil and are not harmful to humans |
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| classification of fungal species (based on site of infection) |
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| -superficial mycoses -subcutaneous mycoses -opportunistic mycoses -systemic mycoses |
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| 4 virulence mechanisms |
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| -produce a capsular polysaccharide -metabolize keratin (colonization of epidermis, hair, nails) -grow at host temp (37) as well as temp or normal environment(25) -can survive in lowered oxidation-reduction state, situation found in damaged tissues |
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| producing a capsular polysaccharide... |
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| -isolates organism from surrounding environment -plays role in triggering immune response |
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| superficial mycoses |
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| -cause infections of outermost layers of skin and hair -common -include ringworm and athlete's foot -tissue damage is minimal and rarely induces immune response |
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| subcutaneous mycoses |
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| -development of lesions at sites of infection -involves deep layers of epidermis like subcutaneous or bone -feet, legs, arms, hands, butt -commonly found in soil or decaying vegetation -hard to treat, requires surgery -Sporotrichosis found mostly in gardeners and farmers -Chromoblastomycosis. Pigmented fungi in the soil may cause this disease |
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| Candida species |
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| -Most commonly causes vaginitis, thrush, balanitis, and cutaneous infections -women with diabetes, taking contraceptives, having menopause are more prone to vaginitis (high sugar low pH) -150+ species -few are important pathogens -C. albicans is part of the normal flora -can cause opportunistic infections in people who are immunosuppressed, debilitated, or received prolonged antibacterial therapy |
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| opportunistic mycoses |
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| -caused by fungi found in environment or in normal flora -may take advantage of weaker host and causes disease -most common are candida, aspergillus, pneumoncystis |
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| symptoms of opportunistic mycoses |
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| -thrush (infection of tongue/oral muscosa often seen in HIV) -esophagitis (painful swallowing, chest pain)(hematologic disease/HIV) -vaginitis (women pregnant, diabetic, receiving antibiotics) -chronic mucocutaneous candidiasis (lesions on face, scalp, hands, defects in T cells) |
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| Pneumocystis carinii |
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| -widespread in environment -doesnt cause illness in healthy people -causes lung infection in people with weak immune systems, AIDS, organ/bone marrow transplant, premature/malnourished children -prior to AIDS, p. carinii pneumonia was rare |
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| control of fungi |
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| 1. Antibiotic griseofulvin interferes with nuclear division by binding to tubulin 2. Antimetabolites interfere with normal nucleic acid synthesis. 3. Antibiotics such as amphotericin B, pimaricin, and nystatin are fungicidal drugs that bind to ergosterol and cause leakage of cellular contents 4. Antibiotics such as clotrimazole, miconazole, itraconazole interfere with ergosterol biosynthesis 5. Naftifine (Naftin) and terbinafine (Lamisil) block synthesis of ergosterol |
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| systemic mycoses |
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| -caused by most virulent fungi -may cause serious progressive systemic disease -primarily originate in lung but may spread |
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| Useful fungi |
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| -baking and brewing (S. cerevisiae) -antibiotics (penicillin, cephlosporin) -citric acid in Coke (Aspergillus niger) -steroids and hormones (birth control pill) -cheese |
