Glycogen metabolism, gene expression levels and reversible dimorphim of Candida albicans PKA mutant strains

MARIA SUSANA DI BERNARDO; GIACOMETTI, R.

Santa Fe

Congreso; XLII Reunión Anual de la SAIB; 2006

SAIB

Gene expression levels and reversible Dimorphim of Candida albicans PKA mutant strains Giacometti, Romina and Passeron, Susana. IBYF-CONICET, Facultad de Agronomía, UBA., Buenos Aires, Argentina. E-mail: rgenetica@hotmail.com Candida albicans cAMP pathway co-ordinates basic cellular processes such as dimorphic shifts, carbon metabolism and the cell cycle. Morphogenesis of an achieved set of mutant strains devoid of one or two alleles of PKA catalytic subunits (TPK1 or TPK2) and/or the regulatory subunit (BCY1) was assessed in solid and liquid media. Under conditions in which wild-type and a number of strains exhibited wrinkled colonies composed of filamentous forms (pseudohyphae and true hyphae); and reverted to the yeast morphology when growing in a minimal medium, the homozygous bcy1 tpk2 strain was unable to switch to this phenotype. Interestingly the mutant strain tpk2 carrying single alleles of TPK1 and BCY1 gave a non-germinative phenotype. It is known that some PKA mutants in the glucose-deprived state are unable to store carbohydrates like glycogen and/or trehalose. Glycogen accumulation was tested in the PKA mutants. It was found that some of them, particularly those devoid of one or both TPK1 alleles were defective in entry into stationary phase an in glycogen accumulation as assessed by iodine/iodide staining, and total glycogen measurement. Also, through RT-PCR we studied the expression of PKA coding genes and those involved in glycogen metabolism. Supported by grants from University of Saarland (Germany) and CONICET,