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Applied and Environmental Microbiology, July 2001, p. 3134-3139, Vol. 67, No. 7
Department of Biological
Sciences1 and Department of Chemistry
and Biochemistry,2 University of South
Carolina, Columbia, South Carolina 29208
Received 15 March 2001/Accepted 8 May 2001
The prominence of the
0099-2240/01/$04.00+0 DOI: 10.1128/AEM.67.7.3134-3139.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Nuclear Magnetic Resonance Analysis of
[1-13C]Dimethylsulfoniopropionate (DMSP) and
[1-13C]Acrylate Metabolism by a DMSP Lyase-Producing
Marine Isolate of the
-Subclass of
Proteobacteria

-subclass of Proteobacteria in
the marine bacterioplankton community and their role in dimethylsulfide (DMS) production has prompted a detailed examination of
dimethylsulfoniopropionate (DMSP) metabolism in a representative
isolate of this phylotype, strain LFR. [1-13C]DMSP was
synthesized, and its metabolism and that of its cleavage product,
[1-13C]acrylate, were studied using nuclear magnetic
resonance (NMR) spectroscopy. [1-13C]DMSP additions
resulted in the intracellular accumulation and then disappearance of
both [1-13C]DMSP and
[1-13C]
-hydroxypropionate
([1-13C]
-HP), a degradation product. Acrylate, the
immediate product of DMSP cleavage, apparently did not accumulate to
high enough levels to be detected, suggesting that it was rapidly
-hydroxylated upon formation. When [1-13C]acrylate was
added to cell suspensions of strain LFR it was metabolized to
[1-13C]
-HP extracellularly, where it first accumulated
and was then taken up in the cytosol where it subsequently disappeared,
indicating that it was directly decarboxylated. These results were
interpreted to mean that DMSP was taken up and metabolized by an
intracellular DMSP lyase and acrylase, while added acrylate was
-hydroxylated on (or near) the cell surface to
-HP, which
accumulated briefly and was then taken up by cells. Growth on acrylate
(versus that on glucose) stimulated the rate of acrylate metabolism
eightfold, indicating that it acted as an inducer of acrylase activity.
DMSP, acrylate, and
-HP all induced DMSP lyase activity. A putative model is presented that best fits the experimental data regarding the
pathway of DMSP and acrylate metabolism in the
-proteobacterium, strain LFR.
*
Corresponding author. Mailing address: Department of
Biological Sciences, University of South Carolina, Columbia, SC 29208. Phone: (803) 777-2322. Fax: (803) 777-4002. E-mail:
yoch{at}biol.sc.edu.
Present address: University of Maryland Center for Vaccine
Development, Baltimore, MD 21201-1509.
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