Appl Environ Microbiol, January 1998, p. 273-278, Vol. 64, No. 1
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
andDepartment of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611-0700
Received 11 August 1997/Accepted 23 October 1997
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 cultures with 3 M NaCl, the intracellular levels of glycine betaine and choline-O-sulfate were 22- and 2.6-fold greater (70 and 46 mM), respectively, than those of cultures without added NaCl. The levels of glycine 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) or choline-O-sulfate (10 mM). The presence of exogenous choline chloride (2 mM) in plate cultures protected the cells from stress from 3 M NaCl. The data suggest that glycine betaine and choline-O-sulfate are secondary osmoprotectants which are effective at the point that the cell is incapable of synthesizing more glycerol.
Journal Series No. RO5664 of the Florida Agricultural Experiment
Station.
Present address: Department of Biology, Johns Hopkins University,
Baltimore, MD 21218-2699.
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