general mycology a brief review

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resistant to antibiotics

Fungi grow in two morphologic forms yeasts or molds Yeast form yeasts grow mainly by budding producing spherical to ellipsoidal cells 3-15 micron in diameter either single or attached to each other forming pseudo hyphae they never produce aerial hyphae this is reflected on morphology of colonies on agar media which resemble bacterial growth the colony are pasty opaque and may be white creamy yellowish red or even black in color the yeast color generally attain a diameter of 0.5- -3 mm within 3 days the mould form the mould grow through the development of tube like extension forming what is known as hypha the mass of interwind hyphae is called mycelium the hypha may be divided into individual cells by septa which is cross walled that present one or two pores The hypha may present no septa and remain as continuous tube apportion of mycelium grows into the medium called vegetative mycelium visible part grow above the medium called aerial mycelium The aerial mycelium gives the colony fluffy appearance and bear the reproductive structures which give the colony its color The mold colony varies in its appearance size from few mm to few cm so the single colony may cover all the surface of the plate it may be Glabrous verrucose fluffy surface texture may be velvety cottony powdery may assume any color or grade of color known in nature Some molds have the character of dimorphism dimorphic moulds as they can grow also in a yeast form it takes place in tissue when the mold invade tissues it change to yeast form or In lab when the colony plated on enriched media such as brain heart infusion agar and incubated at 37c The rigid cell wall of fungi consisted of chitinous microfibrils embedded in a matrix of small polysaccharides protein lipids the major polysaccharide cell wall matrix consisted of glucan, manans, chitosan and galactan Yeasts have soluble peptidomanans as component of their outer cell wall the outer cell wall of dermatophytes contains glycopeptides that may evoke both immediate and delayed hypersensitivity The plasma membrane is similar to the mammalian plasma membrane differ it has the non polar ergosterol instead of cholesterol as a principal sterol this is the site of action of antifungal Fungal nuclei are variable in size and shape and numbers the DNA and associated protein occur as long filaments of chromatin which condense during nuclear division the number of chromosomes varies with particular fungus the fungal cell may contain up to 100 mitochondria

Growth of fungi fungi need for their growth a source of carbon e.g sugar a source of nitrogen e.g peptone inorganic compound as ammonium nitrate and source of inorganic nutrients potassium phosphorous magnesium Water is an absolute requirement for fungi fungi are more tolerant for water stress than other organisms but in draught no growth occur spore can survive in a suitable medium the fungal spores germinate forming germ tubes which develop into hyphae Growth temperature of fungi mesophilic between 10- 40C optimum temperature 25-35C some fungi grow best at 37 C Thermophilic or Thermotolerant they grow at temperature between 20-and 60 C with optimum of 40C Psychrophilic fungi grow at low temperature that reach to-20 as molds which grow on frozen meat e.g. Cladosporium The optimum PH of fungi is in the range 56-6.5 while few fungi grow below ph3 or aboveph9 several acidophilic fungi grow at pH 2 e.g. Aspergillus and penicillium few fungi are basophilic can grow at 10-11 e.g. fusarium exosporium   metabolism of fungi  Metabolism of fungi fungi preferer moist habitat they are heterophilic need carbon in soluble form of carbohydrate as carbon in environment is found as complex polymer they use their own enzyme like cellulase chitinase in degrading cellulose lignin Fungi cannot fix gaseous nitrogen but they can utilize nitrate ammonia some amino acids by direct uptake by hyphal membrane they can utilize more complex nitrogen sources such as protein and peptides as they can utilize extracellular proteases that degrade amino acids into amino acids Fungi require macro and micronutrients sometimes vitamins fungal genetic  atypical model for studing genetic saccharomyces serviceae

diseases caused by fungi




lab diagnosis of fungal diseases

  antifungal  Drug used in treating fungal diseasesGET ON UDEMY 



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