Medical Microbiology

350 5 GeneralMycology

&Mycelium:thisisthewebormatlikestructureofhyphae.Substratemy-

celia(specializedfornutrition)penetrateintothenutrientsubstrate,whereas

aerialmycelia(forasexualpropagation)developabovethenutrientmedium.

&Fungalthallus:thisistheentiretyofthemyceliaandisalsocalledthe

fungalbodyorcolony.

&Yeast:thebasicelementoftheunicellularfungi.Itisroundtoovaland 3 –

10 lmindiameter.Severalelongatedyeastcellschainedtogetherandresem-

blingtruehyphaearecalledpseudohyphae.

&Dimorphism:somefungalspeciescandevelopeithertheyeastorthemy-

celiumformdependingontheenvironmentalconditions,apropertycalled

dimorphism.Dimorphicpathogenicfungitaketheformofyeastcellsinthe

parasiticstageandappearasmyceliainthesaprophyticstage.

BasicMorphologicalElementsofFungi

Fig.5. 1 Therearetwobasicmorphologicalforms:hyphaandyeast.

aHypha,septate,ornonseptate.

bMycelium:webofbranchedhyphae.

cYeastform,budding(diameterofindividualcell 3 – 5 lm).

dPseudomycelium.

a b

c d

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Kayser, Medical Microbiology © 2005 Thieme