Uptake of carbon and phosphorous from an agar medium
The uptake of these two nutrients can easily be visualized by a simple technique Fig 13 . Fungi are grown on top of a cellophane membrane on a defined agar medium containing glucose and minerals including phosphorous . The fungus cannot penetrate the membrane but can take up small molecular compounds through the membrane. When the fungal colony has grown out the outline of the colony can be marked on the bottom of the Petri dish and the colony can be removed by lifting off the membrane. The...
Nitrogen
Like all organisms fungi needs nitrogen for building proteins and nucleic acids. Fungi also need nitrogen for the amino sugars they use to build the chitin in their cell walls. Polymeric nitrogen sources are broken down by extracellular proteases and nucleases. The resulting peptides, purines, pyrimidines and amino acids are then pumped into the cytoplasm by special transporters in the plasma membrane. From these monomers the fungi can build polymers Fig 12 . Fig 12. Nitrogen metabolism in...
Mycelial growth habit and nutrition
Fungi are not particular good at taking up nutrients compared to bacteria. On the other hand the mycelial growth habit have the following advantages The fungus can often use different types of nutrients present at different locations simultaneously. There could be a large amount of carbon available in one location and a lack of for example nitrogen for good growth at this location. If this nitrogen can be imported from another location good growth can take place. The fungal hyphae can penetrate...
Tip growth and branching the HGU
The hyphal tip grows and when the hyphae has grown for a while it branches. When these branch hyphae have grown for a while more they branch in their turn eventually forming a mycelium. In trying to describe fungal growth this process was studied in detail and it was observed that as the total mycelium length increases the total number of tips also increases. Both these measurements of fungal growth increased exponentially. If you then divided the total hyphal length with the total number of...