CHOLINE DERIVATIVES INVOLVED IN OSMOTOLERANCE OF PENICILLIUM-FELLUTANUM

Penicillium fellutanum is osmotolerant and xerotolerant when cultured in a low-phosphate medium containing 3 M NaCl. Glycerol and erythritol accumulated in cultures with NaCl concentrations up to 2 M; glycerol was the only detectable polyol in cultures containing 3 M NaCl. In cul tures with 3 M NaCl, the intracellular levels of glycine betaine and c holine-O-sulfate were 22- and 2.6-fold greater (70 and 46 mM), respect ively, than those of cultures without added NaCl. The levels of glycin e betaine and glycerol decreased in mycelia transferred from a medium containing 3 M NaCl into a fresh medium without added NaCl, NaCl at 3 M inhibited mycelial mass accumulation; this inhibition was partially corrected by supplementation of cultures with glycine betaine (2 mM) o r choline-O-sulfate (10 mM). The presence of exogenous choline chlorid e (2 mM) in plate cultures protected the cells from stress from 3 M Na Cl. The data suggest that glycine betaine and choline-O-sulfate are se condary osmoprotectants which are effective at the point that the cell is incapable of synthesizing more glycerol.