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| Titel |
Optimizing sample pretreatment for compound-specific stable carbon isotopic analysis of amino sugars in marine sediment |
| VerfasserIn |
R. Zhu, Y.-S. Lin, J. S. Lipp, T. B. Meador, K.-U. Hinrichs |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 17 ; Nr. 11, no. 17 (2014-09-11), S.4869-4880 |
| Datensatznummer |
250117590
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| Publikation (Nr.) |
 copernicus.org/bg-11-4869-2014.pdf |
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| Zusammenfassung |
| Amino sugars are quantitatively
significant constituents of soil and marine sediment, but their sources and
turnover in environmental samples remain poorly understood. The stable carbon
isotopic composition of amino sugars can provide information on the
lifestyles of their source organisms and can be monitored during incubations
with labeled substrates to estimate the turnover rates of microbial
populations. However, until now, such investigation has been carried out only
with soil samples, partly because of the much lower abundance of amino sugars
in marine environments. We therefore optimized a procedure for
compound-specific isotopic analysis of amino sugars in marine sediment,
employing gas chromatography–isotope ratio mass spectrometry. The whole
procedure consisted of hydrolysis, neutralization, enrichment, and
derivatization of amino sugars. Except for the derivatization step, the
protocol introduced negligible isotopic fractionation, and the minimum
requirement of amino sugar for isotopic analysis was 20 ng, i.e., equivalent
to ~8 ng of amino sugar carbon. Compound-specific stable carbon
isotopic analysis of amino sugars obtained from marine sediment extracts
indicated that glucosamine and galactosamine were mainly derived from organic
detritus, whereas muramic acid showed isotopic imprints from indigenous
bacterial activities. The δ13C analysis of amino sugars provides a
valuable addition to the biomarker-based characterization of microbial
metabolism in the deep marine biosphere, which so far has been lipid oriented
and biased towards the detection of archaeal signals. |
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