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There are two principle types of fungi; the moulds and the yeasts. The moulds are further divided into filamentous or dimorphic fungi.  
 
There are two principle types of fungi; the moulds and the yeasts. The moulds are further divided into filamentous or dimorphic fungi.  
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Filamentous fungal '''hyphae''' are the branching tubular structures of moulds which become entwined as the fungi grows to form a '''mycelium'''. Hyphae grow by apical elongation as new wall material is laid down constantly at the tips of the terminal and lateral branches. Septate hyphae are divided by cross walls into '''septa'''. Each septum has a small central pore (dolipore) maintaining protoplasmic continuity throughout the hyphae, allowing rapid nutrient transport and nuclear migration. Dead or damaged parts of septate hyphae are cut off by a plug blocking the septal pore. Non-septate hyphae only form cross walls to cut off dead or damaged parts of the hyphae and to delimit reproductive organs. There are arial (above the surface) and vegetative (surface) hyphae. The aerial hyphae produce spores which are reproductive fungal cells and vegetative mycelium have an assimilative function. There are two main types of spore produced,  '''conidiospores''' and '''sporangiospores'''. These produce asexual spores called '''conidia''' which are relatively resistant to physical and chemical agents.
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Filamentous fungal '''hyphae''' are the branching tubular structures of moulds which become entwined as the fungi grows to form a '''mycelium'''. Hyphae grow by apical elongation as new wall material is laid down constantly at the tips of the terminal and lateral branches. Septate hyphae are divided by cross walls into '''septa'''. Each septum has a small central pore (dolipore) maintaining protoplasmic continuity throughout the hyphae, allowing rapid nutrient transport and nuclear migration. Dead or damaged parts of septate hyphae are cut off by a plug blocking the septal pore. Non-septate hyphae only form cross walls to cut off dead or damaged parts of the hyphae and to delimit reproductive organs. There are aerial (above the surface) and vegetative (surface) hyphae. The aerial hyphae produce spores which are reproductive fungal cells and vegetative mycelium have an assimilative function. There are two main types of spore produced,  '''conidiospores''' and '''sporangiospores'''. These produce asexual spores called '''conidia''' which are relatively resistant to physical and chemical agents.
    
Dimorphic fungi develop as a mycelium or into another form depending on environmental conditions. There is usually a yeast like parasitic phase and a mycelial saprophytic phase. Dimorphic fungi show phenotypic duality and more than one physiological factor may be involved in dimorphic changes.
 
Dimorphic fungi develop as a mycelium or into another form depending on environmental conditions. There is usually a yeast like parasitic phase and a mycelial saprophytic phase. Dimorphic fungi show phenotypic duality and more than one physiological factor may be involved in dimorphic changes.
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