Patrick Billard

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A PCR approach was developed to assess the occurrence and diversity of arsenite transporters in arsenic-resistant bacteria. For this purpose, three sets of degenerate primers were designed for the specific amplification of approximately 750bp fragments from arsB and two subsets of ACR3 (designated ACR3(1) and ACR3(2)) arsenite carrier gene families. These(More)
The arsenic resistance gene cluster of Microbacterium sp. A33 contains a novel pair of genes (arsTX) encoding a thioredoxin system that are cotranscribed with an unusual arsRC2 fusion gene, ACR3, and arsC1 in an operon divergent from arsC3. The whole ars gene cluster is required to complement an Escherichia coli ars mutant. ArsRC2 negatively regulates the(More)
The impact of both organic and inorganic pollution on the structure of soil microbial communities is poorly documented. A short-time batch experiment (6 days) was conducted to study the impact of both types of pollutants on the taxonomic, metabolic and functional diversity of soil bacteria. For this purpose sand spiked with phenanthrene (500 mg kg−1 sand)(More)
To determine the amount of metals detectable by bacteria, two plasmids were constructed in which the metal-inducible zntA and copA promoters from Escherichia coli were fused to a promoterless Vibrio fischeri luxCDABE operon. The luminescence response of E. coli bearing these constructs was studied as a function of the concentration of several heavy metals(More)
OBJECTIVES To survey recent advances in the application of bioluminescence to public health problems. The usefulness of bacterial (lux) and eucaryotic (luc) luciferase genes is presented, along with several examples that demonstrate their value as "reporters" of many endpoints of clinical concern. CONCLUSIONS The development of new technologies for(More)
Denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR (qPCR) were successfully developed to monitor functional aoxB genes as markers of aerobic arsenite oxidizers. DGGE profiles showed a shift in the structure of the aoxB-carrying bacterial population, composed of members of the Alpha-, Beta- and Gammaproteobacteria, depending on(More)
We describe a real-time PCR assay for the quantitative detection of arsB and ACR3(1) arsenite transporter gene families, two ubiquitous and key determinants of arsenic resistance in prokaryotes. The assay was applied in batch growth experiments using a wasteland soil bacterial community as an inoculum to investigate the effect of increasing arsenite(More)
The toxicity of quantum dots (QDs) has been commonly attributed to the release of metal ions from the core as well as to the production of reactive oxygen species. However, the information related to the stability of the nanoparticles are relatively scarce although this parameter may strongly influence their toxicity. The stability of aminosilane-capped ZnO(More)
The glutathione-S-transferase (GST) proteins represent an extended family involved in detoxification processes. They are divided into various classes with high diversity in various organisms. The Ure2p class is especially expanded in saprophytic fungi compared to other fungi. This class is subdivided into two subclasses named Ure2pA and Ure2pB, which have(More)
A phosphate sensor plasmid was constructed, in which the inducible promoter of the alkaline phosphatase gene (phoA) from Escherichia coli is fused to the bioluminescence genes from Vibrio fischeri. The reporter construct was introduced into E. coli MG1655 and the rhizosphere coloniser Pseudomonas fluorescens DF57, which produced light in a dose-dependent(More)