INFLUENCE OF NA-ALBICANS( AND ANIONS ON THE DIMORPHIC TRANSITION OF CANDIDA)

The effect of Na+ (Cl- or gluconate salt) on growth and dimorphic pote ntial of the pathogenic yeast Candida albicans has been examined. Prof iles of germ tube formation as a function of salt addition. ph and tem perature indicated Na+ inhibition of germ tube outgrowth at high ambie nt pH (ph 8.0) which was exacerbated by replacement of Cl- with glucon ate (as an impermeant analogue). At acidic pH (pH 5.5) and permissive temperature (37 degrees C), gluconate alone promoted the dimorphic tra nsition. Rates of glucose-induced medium acidification and plasma memb rane H+-ATPase activity have been measured to assess whether salt trea tments could retard the cytoplasmic alkalinization known to precede ge rm tube formation. The precise site of Na+ action remains unclear but the anion effects may be interpreted in terms of anion-exchanger and c hannel activity acting to modulate cytosolic pH.