Role of nutritional status of the cell in pH regulated dimorphism of Candida albicans.
Stationary phase cells of Candida albicans are under the control of glucose repression, as indicated by the inhibition of germ tube formation by glucose. This 'glucose effect' was absent in starved cells which were derived from similar stationary phase cells. Moreover, starved cells required glucose for germ tube formation, suggesting that it was depletion of energy reserves which was the main factor overriding the 'glucose repression machinery' during starvation. High concentration of phosphate in Lee's medium was the reason for the reduced ability of the starved cells to form germ tubes at pH 4.5 (20% of cells compared to 88% at pH 6.8). However, when phosphate was replaced or its concentration reduced, germ tube formation occurred as frequently at pH 4.5 as at pH 6.8. This 'phosphate effect' was not observed in stationary phase cells, as they were already repressed by glucose.
Paranjape
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Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
Datta
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D002176:Candida albicans / Q000378:metabolism / Q000502:physiology*; D003470:Culture Media; D000242:Cyclic AMP / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D010710:Phosphates / Q000494:pharmacology
D003470:Culture Media; D010710:Phosphates; D000242:Cyclic AMP; D005947:Glucose