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