Osmoregulation and the Genetic Induction of Glycerol-3-phosphate Dehydrogenase by NaCl in the Euryhaline Yeast Debaryomyces hansenii.

: In the yeasts Saccharomyces cerevisiae and Debaryomyces hansenii, glycerol-3-phosphate dehydrogenase (NAD+-GPD) is believed to be the enzyme controlling the synthesis of glycerol in osmotically challenged cells. Consistent with this concept, immunoblot analyses demonstrated quantitative increases in NAD+-GPD 30 minutes after the addition of NaCl to actively growing D. hansenii cells; Northern blot analyses showed increases in GPD-messenger RNA within 15 minutes after the addition of salt. There appears to be an upper limit of salt concentration above which the cells appear to be less responsive. The results we describe support the concept of transcriptional regulation of NAD+-GPD in D. hansenii.