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Identification of Methanotrophic Lipid Biomarkers in Cold-Seep Mussel Gills: Chemical and Isotopic AnalysisA lipid analysis of the tissues of a cold-seep mytilid mussel collected from the Louisiana slope of the Gulf of Mexico was used in conjunction with a compound-specific isotope analysis to demonstrate the presence of methanotrophic symbionts in the mussel gill tissue and to demonstrate the host's dependence on bacterially synthesized metabolic intermediates. The gill tissue contained large amounts of group-specific methanotrophic biomarkers, bacteriohopanoids, 4-methylsterols, lipopolysaccharide-associated hydroxy fatty acids, and type I-specific 16:1 fatty acid isomers with bond positions at delta-8, delta-10, and delta-ll. Only small amounts of these compounds were detected in the mantle or other tissues of the host animal. A variety of cholesterol and 4-methylsterol isomers were identified as both free and steryl esters, and the sterol double bond positions suggested that the major bacterially derived gill sterol(11.0% 4(alpha)-methyl-cholesta-8(14), 24-dien-3(beta)-ol) was converted to host cholesterol (64.2% of the gill sterol was cholest-5-en-3(beta)-ol). The stable carbon isotope values for gill and mantle preparations were, respectively, -59.0 and -60.4 per thousand for total tissue, -60.6 and -62.4 per thousand for total lipids, -60.2 and -63.9 per thousand for phospholipid fatty acids, and -71.8 and -73.8 per thousand for sterols. These stable carbon isotope values revealed that the relative fractionation pattern was similar to the patterns obtained in pure culture experiments with methanotrophic bacteria further supporting the conversion of the bacterial methyl-sterol pool.
Document ID
19970015326
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Jahnke, Linda L.
(NASA Ames Research Center Moffett Field, CA United States)
Summons, Roger E.
(Australian Geological Survey Organisation, Canberra Australian Capital Territory, Australia)
Dowling, Lesley M.
(Australian Geological Survey Organisation, Canberra Australian Capital Territory, Australia)
Zahiralis, Karen D.
(Search for Extraterrestrial Intelligence Inst. Mountain View, CA United States)
Date Acquired
August 17, 2013
Publication Date
February 1, 1995
Publication Information
Publication: Applied and Environmental Microbiology
Publisher: American Society for Microbiology
Volume: 61
Issue: 2
ISSN: 0099-2240
Subject Category
Life Sciences (General)
Report/Patent Number
NASA-TM-112678
NAS 1.15:112678
Accession Number
97N71332
Funding Number(s)
CONTRACT_GRANT: NSF EAR-91-58113
Distribution Limits
Public
Copyright
Public Use Permitted.
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