Design and comparative characterization of RecA variants.

RecA plays a central role in DNA repair and is a main actor involved in recombination and activation of the SOS response. It is also used in the context of biotechnological applications in recombinase polymerase isothermal amplification (RPA). In this work, we studied the biological properties of seven RecA variants, in particular their recombinogenic activity and their ability to induce the SOS response, to better understand the structure-function relationship of RecA and the effect of combined mutations.

RecA and DNA recombination: a review of molecular mechanisms.

Recombinases are responsible for homologous recombination and maintenance of genome integrity. In Escherichia coli, the recombinase RecA forms a nucleoprotein filament with the ssDNA present at a DNA break and searches for a homologous dsDNA to use as a template for break repair. During the first step of this process, the ssDNA is bound to RecA and stretched into a Watson-Crick base-paired triplet conformation.

Usefulness of pan-fungal NASBA test for surveillance of environmental fungal contamination in a protected hematology unit.

A pan-fungal nucleic acid sequence based applification (NASBA) test was adapted and used for the first time to detect and quantify the level of filamentous fungi in environmental samples. Surface samples (n = 356) collected in a controlled air flow hematology ward were tested by mycological culture and the pan-fungal NASBA test. The overall percentage of agreement between culture and NASBA was 88%, the Kappa coefficient was equal to 0.

Detection of single-nucleotide polymorphisms in cancer-related genes by minisequencing on a microelectronic DNA chip.

The ability to realize simultaneous genotyping of multiple single-nucleotide polymorphisms or mutations is valuable in DNA samples from complex multigenic pathologies such as cancer. In this way, the complexity (number of hybridization units per chip) of the developed MICAM DNA chip, and the orientation of the grafted pyrrole oligonucleotides, make it particularly well adapted to the analysis of single-nucleotide polymorphisms/mutations in multiple potential tumoral markers. The proposed genotyping methodology is based on solid-phase minisequencing, where oligonucleotides are designed to anneal immediately upstream of the polymorphism sites, and labeled dideoxynucleotides are used as substrates for polymerase extension.

Detection of single nucleotide polymorphisms by minisequencing on a polypyrrole DNA chip designed for medical diagnosis.

With the increasing availability of genetic information and its relationship to human diseases, there is a growing need in the medical diagnostic field for technologies that can proceed to the parallel genotyping of multiple markers. In this paper, we report the development of a new flexible microarray-based method that aims to be inexpensive, accurate, and adapted to routine analysis. The construction of the MICAM (MICrosystem for Analysis in Medicine) DNA chip is based on the controlled electro-synthesis of a conducting polymer film bearing oligonucleotide probes on gold electrodes.

Suppression of Escherichia coli formate hydrogenlyase activity by trimethylamine N-oxide is due to drainage of the inducer formate.

The effect of the addition of trimethylamine N-oxide (TMAO) in the growth medium on Escherichia coli anaerobic fermentative and respiratory pathways was examined. Formate dehydrogenase H (FDH-H) activity was totally repressed by the addition of 40 mM TMAO, whereas the overall hydrogenase (HYD) activity was reduced by 25%. Accordingly, expression of lacZ operon fusions with the fdhF and hycB structural genes specifying FDH-H and HYD3 was reduced sevenfold and eightfold, respectively, leading to suppression of an active formate hydrogenlyase system.