Document Detail

NMR 13C-isotopic enrichment experiments to study carbon-partitioning into organic solutes in the red alga Grateloupia doryphora.
MedLine Citation:
PMID:  15061080     Owner:  NLM     Status:  MEDLINE    
The red alga Grateloupia doryphora Montagne (Howe) (Cryptonemiales, Halymeniaceae) was used as a model to investigate the effects of changes in seawater salinity on the intracellular low-molecular-weight organic compounds. Carbon-partitioning into major organic solutes was followed by 13C nuclear magnetic resonance (NMR) spectroscopy on living algae incubated in NaH13CO3-enriched seawater, and by high resolution 1H and 13C NMR experiments performed on 13C-enriched algal extracts. NMR and high performance liquid chromatography (HPLC) analyses both demonstrated that floridoside level was the most affected by changes in salinity: it rose under the hypersaline treatment and decreased under hyposaline one. Moreover, at low salinity, the high labeling of floridoside (45.3% 13C-enrichment for C1) together with its low concentrations both provided evidence of great increase in the de novo biosynthesis and turnover rate. Our experiments also demonstrated a high incorporation of photosynthetic carbon into amino acids, especially glutamate, under hypoosmotic conditions. On the other hand, isethionic acid and N-methyl-methionine sulfoxide were only partly labeled, which indicates they do not directly derive from carbon photoassimilation. In algae exposed to high salinity, elevated concentrations of floridoside coupled to a low labeling (9.4%) were observed. These results suggest that hyperosmotic conditions stimulated floridoside biosynthesis from endogen storage products rather than from carbon assimilation through photosynthesis.
Christelle Simon-Colin; Nelly Kervarec; Roger Pichon; Eric Deslandes
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Plant physiology and biochemistry : PPB / Société française de physiologie végétale     Volume:  42     ISSN:  0981-9428     ISO Abbreviation:  Plant Physiol. Biochem.     Publication Date:  2004 Jan 
Date Detail:
Created Date:  2004-04-05     Completed Date:  2004-05-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9882449     Medline TA:  Plant Physiol Biochem     Country:  France    
Other Details:
Languages:  eng     Pagination:  21-6     Citation Subset:  IM    
Laboratoire d'Ecophysiologie et de Biotechnologie des Halophytes et des Algues Marines (LEBHAM), Université de Bretagne Occidentale-IUEM, Technopôle Brest-Iroise, 29280 Plouzané, France.
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MeSH Terms
Algae, Red / metabolism*
Amino Acids / chemistry,  metabolism
Carbon Isotopes
Glycerol / analogs & derivatives*,  metabolism
Isethionic Acid / metabolism
Lactic Acid / metabolism
Nuclear Magnetic Resonance, Biomolecular / methods*
Osmolar Concentration
Sodium Bicarbonate / chemistry,  metabolism*
Sodium Chloride / chemistry
Sulfoxides / chemistry,  metabolism
Water-Electrolyte Balance / physiology
Reg. No./Substance:
0/2-galactopyranosylglycerol; 0/Amino Acids; 0/Carbon Isotopes; 0/Sulfoxides; 107-36-8/Isethionic Acid; 144-55-8/Sodium Bicarbonate; 50-21-5/Lactic Acid; 56-81-5/Glycerol; 7647-14-5/Sodium Chloride

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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