Microbio -7- mycology and fungal pathogens

Question Answer
study devoted to study of fungi mycology
major decomposers of carbon compounds on earth found widespread in nature fungi
How can fungi morphologically present unicellular as small as a bacteria or multicellular complex organisms as muschrooms
Are fungi eukaryotes or prokaryotes eukarytoes
Are fungi unicellular or multicellular both
What is the cytoplasm surrounded by in fungi and how is this different then mammalian cells cytoplasm is bound by a cytoplasmic membrane which has actin and contain ergosterol instead of cholesterol as mammalian cells
Why is the fact that fungi have ergesterol in place of cholesterol important to medicine we can target ergesterol with medications to fight fungal infections
do fungi have organelles yes all the same organelles as mammals
what is the fungal cell wall made of made of polysacharrides such as mannan, glucans, and chitins
composed of long unbranched chains of poly-n-acetylglucosamine inert insoluble and rigid provides structural support for the fungi cell wall Chitins
Glucosyl polymers may form fibril to increase the strength of the fungal cell wall Glucans
form complex with protien and is present on the surface and structural cell matrix of the fungal cell wall determinants of serologic specificities mannan
what are the strucutres in the fungal cell wall that are most responsible for causing immunological responses to most of the medically important fungi Mannans and galactomannans
What is the metabolism of fungi heterotrophic- which means then need exogenous carbon and nitrogen they don't have photosynthetic mechanisms
are there any anaerobic fungi none there are aerobes and some faculative anaerobes
How do fungi metabolize larger or tougher structure to break down they use an exoenzyme to solublizes the structures these enzymes often function as a virulence factor
what is clinically important of the exoenzymes fungi use for metabolism it can function as a virulence factor
What are the three divisions of fungi based on the temperature at which they grow psychrophile 0-20c
mesophile 30-40c
thermophilic 40-50c
what is the PH range for fungi 2.2-8.5 clinically important grow at 6.5-7.0
What is a critical environmental condition for most fungi for the to grow appropriatly water availability most require 80-90% humidity
are most fungi photosensitive yes
What are the different morphologies for fungi yeast, mold(hypha or mycellium) or dimorphic can be both
What is dimorphism ability of a fungus to grow as a mold or yeast (yeast like form)
At what temperature does dimorphic fungi grow as a mold and what temperature as a yeast mold at ambient room temp
yeast at 37c (body temp)
what are the 5 medically important dimorphic fungi blastomyces dermatitidis
coccidioides immitis
histoplasma capsulatum
paracoccidioidis brasiliensis
sporothrix schenckii
What disease can bastomyces dermatitidis, histoplasma capsulatum and paracoccidioidis barsiliensis cause pneumonia
What disease can coccidioides immitis cause respiratory pathogen
what disease can sporothrix schenckii cause rose gardeners disease sub q fungal infection
What two ways can fungi reproduce asexual- via budding, or seperation of hyphal elements
Sexual- two cells fuse to form diploid nucleus which goes through meiosis to form spores
part of the fungi below the surface is called vegetative hypha- acquire nutrients for the fungus
part of the fungi above the surface is called aerial hypha involved in reproduction via spores or conidia
what are the three types of spores formed in sexual reproduction of fungi zygospores, ascospores and basidiospores
what is different between ascospores and basidiospores ascospores are borne internally in a sac, basidiospores borne externally on a club sheath structure
what is unique about yeast forms of fungi they can split like bacteria through fission or can undergo budding
What are the 4 phylum of fungi zygomycota, ascomycota, basidiomycota, deuteromycota
sexual reproduction through zygospores asexual reproduction through sporangiospores zygomycota
sexual reproduction through ascospores within sacs or asci asexual reproduction through blastoconidia or conidia on conidiophores ascomycota
sexual reproduction through basidiospores on the surface of basidium asexual repro through conidiogenesis basidiomycota
no sexual stage, asexual repro through conidiogenesis deuteromycota
Classification of fungi that involves outer layer of skin, nail or hair rarely invade deeper tissues or viscera superficial fungi
fungi confined to sub q tissues rarely spread systematically usually form deep ulcerated skin lesions or fungating masses subcutaneous fungi
class of fungi that may involve deep viscera and become widely disseminated in the body Systemic (deep) fungi
class of fungi that have low inherent virulence and are common in all environments and only take root when a chance presents itself opportunistic mycoses
systemic mycosis that can infect the brain aspergillus fumigatus
Systemic mycosis that can infect lungs especially in immunocompromised patients pneumocystis carinii
What are some factors that can predispose an individual to fungal infections steroid hormone therapy
prolonged antibiotic treatment
long term treatment stomach with h2 blockers
diabetes mellitus
high starch or sugar diets
compromised immune system
what part of the immune system kills most fungi but what fungi can avoid it innate immune response with neutrophils kills most fungi; dimorphic fungi are resistant to phagocytosis
part of the immune system that produces antibodies to opsonize the fungi promoting phagocytosis humoral immune response of adaptive immune system
Part of immune system where T-cells protect the body from fungal infections Cell mediated immune response of adaptive immune system
how can you diagnose fungal infections KOH prep
DNA probe- limited effectiveness
identify by characteristics mold or yeast
What are the three areas that drug treatments target for antifungal therapy target plasma membrane synthesis and production, target cell division, targer nucleic acid synthesis
what drugs target plasma membrane synthesis/ function of fungi polyenes, azoles and allyamines
drug that targets cell division of fungi griseofulvin
drug that targets nucleic acid synthesis of fungi flucytosine
how do allyamines stop plasma membrane synthesis/function inhibit cyochrome enzyme p450 demethylase that converts lanosterol to ergosterol that is a major part of cell membrane
how does griseofulvin stop fungi cell division only effective against fungi in keratininc skin layers it disrupts microtubules and stops cell divisions
how does flucytosine stop fungi nucleic acid synthesis it inhibits thymidylate synthatase

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