Molecular quantification of sulfate-reducing microorganisms (carrying dsrAB genes) by competitive PCR in estuarine sediments
Résumé
In this study, we describe a competitive polymerase chain reaction (PCR) for the quantification of the sequences of dsrAB in sulfate-reducing microorganisms. We used the dsr1F/dsr4R set of primers, previously designed by Wagner et al. (1998), and a competitor sequence was constructed from the dsrAB genes of Desulfovibrio vulgaris. The detection limit of competitive PCR corresponded to 45 copies of the dsrAB genes per ng of extracted DNA, and most of the dsrAB sequences amplified and cloned from DNA extracted from Seine estuary sediments were amplified with a similar efficiency. Competitive PCR was then used to assess the abundance of dsrAB genes in the total DNA extracted from the sediment of the Seine estuary mudflats. We observed that the abundance of dsrAB coincided with the variation in the sulfate reduction rate with the depth of the sample, confirming the importance of 'dsrAB' sulfate-reducing microorganisms in sulfidogenesis in anoxic environments. We obtained values ranging from 0.045×103 to 6.63×103 copies of dsrAB per ng of extracted DNA, and values of the sulfate reduction rate ranging from 35 to 158 nmol cm-3 day-1. These results are similar to those obtained in other studies using molecular biology techniques. © 2003 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.
Mots clés
DNA
sulfate
estuarine sediment
polymerase chain reaction
quantitative analysis
sulfate-reducing bacterium
article
Desulfovibrio vulgaris
DNA extraction
dsrab gene
environment
estuary
gene
gene amplification
gene construct
gene sequence
genetic analysis
molecular biology
molecular cloning
priority journal
sample
sediment
sequence analysis
sulfate reducing bacterium