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Carbon-13 NMR studies of salt shock-induced carbohydrate turnover in the marine cyanobacterium Agmenellum quadruplicatumCarbon turnover in response to abrupt changes in salinity, including the mobilization of glycogen for use in osmoregulation was studied with pulse-chase strategies utilizing nuclear magnetic resonance (NMR)-silent and NMR-detectable 12C and 13C isotopes, respectively. Growth of Agmenellum quadruplicatum in 30%-enriched 13C bicarbonate provided sufficient NMR-detectability of intracellular organic osmoregulants for these studies. A comparison of NMR spectra of intact cells and their ethanol extracts showed that the intact cell data were suitable for quantitative work, and, when combined with ESR measurements of cell volumes, yielded intracellular glucosylglycerol concentrations without disrupting the cells. NMR pulse-chase experiments were used to show that 13C-enriched glycogen, which had previously been accumulated by the cells under nitrogen-limited growth at low salinities, could be utilized for the synthesis of glucosylglycerol when the cells were abruptly transferred to hypersaline media, but only in the light. It was also shown that the accumulation of glucosylglycerol in the light occurred on a time scale similar to that of cell doubling. Depletion of glucosylglycerol when cells abruptly transferred to lower salinities appeared to be rapid--the intracellular pool of this osmoregulant was decreased 2-fold within 2 hours of hypotonic shock.
Document ID
20040089829
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Tel-Or, E.
(University of California Berkeley 94720, United States)
Spath, S.
Packer, L.
Mehlhorn, R. J.
Date Acquired
August 21, 2013
Publication Date
January 1, 1986
Publication Information
Publication: Plant physiology
Volume: 82
ISSN: 0032-0889
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: AG-04818
CONTRACT_GRANT: DE-AC03-76SF00098
CONTRACT_GRANT: DE-AT03-80-ER10637
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Life Support Systems
Non-NASA Center

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