Fungi Nutrition

Fungi Nutrition

1. Nutrient Requirements

   • Three types of agar
     • Potato dextrose agar
     • Malt extract agar
     • Cornmeal agar
   • always rich in carbohydrates and slightly acidic
     • fungi exhibit diauxic growth
       • The presence of 2 sugars on a culture growth, the preferred sugar consumed first, which leads to rapid growth, followed by lag phase, and now the cellular machinery used to metabolize second sugar.

2. Special requirements

   • Vitamins
     • Thiamine, biotin
   • Organic nitrogen
     • do not fix atmosphere nitrogen
       • Amino acid transamination
       • Ammonia/Ammonium
         • not a good component because its use lowers pH, thereby inhibiting growth
       • Nitrate
   • Insufficiencies
     • Phosphorus
       • Increased activity of uptake systems
     • Iron
       • Essential donor and acceptor of electrons
       • Often captured by the use of hydroxamate siderophores
       • as heme
     • Sulphur
       • as in cysteine

3. Nutrient capture

   • Electrical field involved in nutrient uptake
     • Exterior apex is more electronegative than the exterior subapical regions
     • Proton export through ATPase (ion pump) and uptake of proton through sitmultaneously transport amino acid
     • Symport proteins are located near the apical tips, whereas the ion pumps are in the subapical regions
   • Yeast do not utilize insoluble erosion zone because they may trapped in their own substrate erosion zone
     • Enzymes are secreted at the tips to degrade the polymers and soluble nutrients are absorbed supapically.
     • Antibiotics are subapically released into the substrate erosion zone to prevent other organisms from using the enzyme digesting product.

4. Reference

   • You can look for the attachment in the notes.
     • The Reference for Fungal nutrition

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