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Combination of biomolecular and stable isotope techniques to determine the origin of organic matter used by bacterial communities: application to sediment

Créach, V. and Lucas, F. and Deleu, C. and Bertru, G. and Mariotti, A. (1999) Combination of biomolecular and stable isotope techniques to determine the origin of organic matter used by bacterial communities: application to sediment. Journal of Microbiological Methods, 38, 43-52. ISSN 0167-7012.

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Official URL: http://dx.doi.org/10.1016/S0167-7012(99)00076-7

Abstract

Natural isotopic composition is a good tool to trace organic matter in ecosystems. Recent studies used a combination of molecular and stable isotope techniques to determine the origin of the organic carbon used by bacteria in the water column. In our study, we show that this procedure can be used for analysis of sediment bacterial communities with few modifications. In the water column, bacterial recovery is done before DNA extraction. In the sediment, we tested qualitatively and quantitatively a direct and indirect extraction of DNA. The direct extraction was the most efficient. It recovered between 3.1 and 15.8 mu g DNA g(-1). dry sediment and the contamination of field samples by eucaryotic DNA was less than 13%. In this preliminary study of the salt marsh ecosystem, the delta(13)C values of DNA (-26 to -24 parts per thousand) recovered from the sediment were close to the delta(13)C values of halophytic plants (-26.4 and -25.3 parts per thousand) showing a relationship between plants and microorganisms, Thus, this procedure can be used to trace the flow of carbon through the sediment microbial biomass and to understand the variation of bacterial activity according to the inputs of allocthonous and autochtonous organic matter. [KEYWORDS: DNA; delta C-13 values; bacteria; sediment Direct extraction; carbon; dna; phytoplankton; purification; probes; bloom; soil; rna]

Item Type:Article
ID Code:10716
Deposited On:25 Nov 2011 01:00
Last Modified:24 Apr 2012 16:38

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