Saint-Sébastien-de-Morsent – La Fosse aux Buis

Le diagnostic a livré les vestiges maçonnés et fossoyés de plusieurs ateliers de briquetiers et tuiliers, le tracé et les fossés bordiers de l’ancien Chemin de Conches à Évreux (figuré sur le plan cadastral de 1841), ainsi qu’une grande fosse charbonneuse peut-être liée à une activité métallurgique. La plus remarquable découverte est celle d’un four de briquetier et de deux fours de tuiliers. Ils sont accompagnés d’au moins cinq probables fosses de marchage, d’au minimum deux grandes fosses d..

Évreux, Guichainville, Le Vieil-Évreux – Zac du Long Buisson

La prescription de diagnostic a porté sur une surface de 90 700 m2 au sud-est de l’agglomération actuelle d’Évreux, en vue de l’aménagement de la Zac « Le Long Buisson ». La principale intervention dans ce secteur réalisée en 2006 au sud et à l’est de la parcelle prescrite a donné lieu à des découvertes de vestiges datés du Paléolithique au viie s. (Marcigny et al. 2006). L’opération de janvier 2016 a livré des artefacts lithiques du Néolithique dont un fragment d’anneau plat à couronne large..

Detecting the molecular scars of evolution in the Mycobacterium tuberculosis complex by analyzing interrupted coding sequences

<p>Abstract</p> <p>Background</p> <p>Computer-assisted analyses have shown that all bacterial genomes contain a small percentage of open reading frames with a frameshift or in-frame stop codon We report here a comparative analysis of these interrupted coding sequences (ICDSs) in six isolates of <it>M. tuberculosis</it>, two of <it>M. bovis </it>and one of <it>M. africanum </it>and question their phenotypic impact and evolutionary significance.</p> <p>Results</p> <p>ICDSs were classified as "common to all strains" or "strain-specific". Common ICDSs are believed to result from mutations acquired before the divergence of the species, whereas strain-specific ICDSs were acquired after this divergence. Comparative analyses of these ICDSs therefore define the molecular signature of a particular strain, phylogenetic lineage or species, which may be useful for inferring phenotypic traits such as virulence and molecular relationships. For instance, <it>in silico </it>analysis of the W-Beijing lineage of <it>M. tuberculosis</it>, an emergent family involved in several outbreaks, is readily distinguishable from other phyla by its smaller number of common ICDSs, including at least one known to be associated with virulence. Our observation was confirmed through the sequencing analysis of ICDSs in a panel of 21 clinical <it>M. tuberculosis </it>strains. This analysis further illustrates the divergence of the W-Beijing lineage from other phyla in terms of the number of full-length ORFs not containing a frameshift. We further show that ICDS formation is not associated with the presence of a mutated promoter, and suggest that promoter extinction is not the main cause of pseudogene formation.</p> <p>Conclusion</p> <p>The correlation between ICDSs, function and phenotypes could have important evolutionary implications. This study provides population geneticists with a list of targets, which could undergo selective pressure and thus alters relationships between the various lineages of <it>M. tuberculosis </it>strains and their host. This approach could be applied to any closely related bacterial strains or species for which several genome sequences are available.</p

ICDS database: interrupted CoDing sequences in prokaryotic genomes

Unrecognized frameshifts, in-frame stop codons and sequencing errors lead to Interrupted CoDing Sequence (ICDS) that can seriously affect all subsequent steps of functional characterization, from in silico analysis to high-throughput proteomic projects. Here, we describe the Interrupted CoDing Sequence database containing ICDS detected by a similarity-based approach in 80 complete prokaryotic genomes. ICDS can be retrieved by species browsing or similarity searches via a web interface (). The definition of each interrupted gene is provided as well as the ICDS genomic localization with the surrounding sequence. Furthermore, to facilitate the experimental characterization of ICDS, we propose optimized primers for re-sequencing purposes. The database will be regularly updated with additional data from ongoing sequenced genomes. Our strategy has been validated by three independent tests: (i) ICDS prediction on a benchmark of artificially created frameshifts, (ii) comparison of predicted ICDS and results obtained from the comparison of the two genomic sequences of Bacillus licheniformis strain ATCC 14580 and (iii) re-sequencing of 25 predicted ICDS of the recently sequenced genome of Mycobacterium smegmatis. This allows us to estimate the specificity and sensitivity (95 and 82%, respectively) of our program and the efficiency of primer determination

Genomics of glycopeptidolipid biosynthesis in Mycobacterium abscessus and M. chelonae

<p>Abstract</p> <p>Background</p> <p>The outermost layer of the bacterial surface is of crucial importance because it is in constant interaction with the host. Glycopeptidolipids (GPLs) are major surface glycolipids present on various mycobacterial species. In the fast-grower model organism <it>Mycobacterium smegmatis</it>, GPL biosynthesis involves approximately 30 genes all mapping to a single region of 65 kb.</p> <p>Results</p> <p>We have recently sequenced the complete genomes of two fast-growers causing human infections, <it>Mycobacterium abscessus </it>(CIP 104536T) and <it>M. chelonae </it>(CIP 104535T). We show here that these two species contain genes corresponding to all those of the <it>M. smegmatis </it>"GPL locus", with extensive conservation of the predicted protein sequences consistent with the production of GPL molecules indistinguishable by biochemical analysis. However, the GPL locus appears to be split into several parts in <it>M. chelonae </it>and <it>M. abscessus</it>. One large cluster (19 genes) comprises all genes involved in the synthesis of the tripeptide-aminoalcohol moiety, the glycosylation of the lipopeptide and methylation/acetylation modifications. We provide evidence that a duplicated acetyltransferase (<it>atf1 </it>and <it>atf2</it>) in <it>M. abscessus </it>and <it>M. chelonae </it>has evolved through specialization, being able to transfer one acetyl at once in a sequential manner. There is a second smaller and distant (<it>M. chelonae</it>, 900 kb; <it>M. abscessus</it>, 3 Mb) cluster of six genes involved in the synthesis of the fatty acyl moiety and its attachment to the tripeptide-aminoalcohol moiety. The other genes are scattered throughout the genome, including two genes encoding putative regulatory proteins.</p> <p>Conclusion</p> <p>Although these three species produce identical GPL molecules, the organization of GPL genes differ between them, thus constituting species-specific signatures. An hypothesis is that the compact organization of the GPL locus in <it>M. smegmatis </it>represents the ancestral form and that evolution has scattered various pieces throughout the genome in <it>M. abscessus </it>and <it>M. chelonae</it>.</p

Allosteric mutants show that PrfA activation is dispensable for vacuole escape but required for efficient spread and <em>Listeria</em> survival <em>in vivo</em>

The transcriptional regulator PrfA controls key virulence determinants of the facultative intracellular pathogen Listeria monocytogenes. PrfA-dependent gene expression is strongly induced within host cells. While the basis of this activation is unknown, the structural homology of PrfA with the cAMP receptor protein (Crp) and the finding of constitutively activated PrfA* mutants suggests it may involve ligand-induced allostery. Here, we report the identification of a solvent-accessible cavity within the PrfA N-terminal domain that may accommodate an activating ligand. The pocket occupies a similar position to the cAMP binding site in Crp but lacks the cyclic nucleotide-anchoring motif and has its entrance on the opposite side of the β-barrel. Site-directed mutations in this pocket impaired intracellular PrfA-dependent gene activation without causing extensive structural/functional alterations to PrfA. Two substitutions, L48F and Y63W, almost completely abolished intracellular virulence gene induction and thus displayed the expected phenotype for allosteric activation-deficient PrfA mutations. Neither PrfA(allo) substitution affected vacuole escape and initial intracellular growth of L. monocytogenes in epithelial cells and macrophages but caused defective cell-to-cell spread and strong attenuation in mice. Our data support the hypothesis that PrfA is allosterically activated during intracellular infection and identify the probable binding site for the effector ligand. They also indicate that PrfA allosteric activation is not required for early intracellular survival but is essential for full Listeria virulence and colonization of host tissues

Seasonal and Regional Dynamics of M. ulcerans Transmission in Environmental Context: Deciphering the Role of Water Bugs as Hosts and Vectors

Buruli ulcer, caused by Mycobacterium ulcerans, is a devastating skin disease. Most cases of Buruli ulcer occur in poor rural communities. As a result, treatment is frequently sought too late and about 25% of those infected—particularly children—become permanently disabled. Outbreaks of Buruli ulcer have always been associated with swampy areas. However, the route(s) of bacillus transmission is (are) still unclear. This Mycobacterium species resides in water where it colonizes many ecological niches such as aquatic plants, herbivorous animals and predatory/carnivorous insects. For several years the role of water bugs as hosts and vectors of M. ulcerans was suspected and was demonstrated under laboratory conditions. The aim of this work was to further assess the role of water bugs as hosts and vectors of M. ulcerans in environmental context. This work identifies several water bug families as hosts of M. ulcerans in Buruli ulcer endemic area. The detection of bacilli in saliva of human biting insects provides further evidence for their role in M. ulcerans transmission. Interestingly, three of these insects are good flyers, and as such could participate in M. ulcerans dissemination

Can Virus-like Particles Be Used as Synergistic Agent in Pest Management?

Among novel strategies proposed in pest management, synergistic agents are used to improve insecticide efficacy through an elevation of intracellular calcium concentration that activates the calcium-dependent intracellular pathway. This leads to a changed target site conformation and to increased sensitivity to insecticides while reducing their concentrations. Because virus-like particles (VLPs) increase the intracellular calcium concentration, they can be used as a synergistic agent to synergize the effect of insecticides. VLPs are self-assembled viral protein complexes, and by contrast to entomopathogen viruses, they are devoid of genetic material, which makes them non-infectious and safer than viruses. Although VLPs are well-known to be used in human health, we propose in this study the development of a promising strategy based on the use of VLPs as synergistic agents in pest management. This will lead to increased insecticides efficacy while reducing their concentrations

Saint-Sébastien-de-Morsent (Eure). La Fosse aux Buis

Des vestiges maçonnés et fossoyés de plusieurs ateliers de briquetiers et tuiliers, le tracé et les fossés bordiers de l’ancien chemin de Conches à Évreux (figuré sur le plan parcellaire de 1841), ainsi qu’une grande fosse à remplissage charbonneux peut-être liée à une activité métallurgique ont été mis au jour à Saint-Sébastien-de-Morsent. La plus remarquable découverte est celle d’un four de briquetier et de deux fours de tuiliers, d’au moins cinq probables fosses de marchage, de deux grand..

Biosynthèse et export des glycopeptidolipides à la surface des mycobactéries

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF