Retrieval of total ozone quantity from high resolution infrared spectra : influence of spectroscopic and physical parameters

In this work, we present the results obtained for total ozone quantity from Jungfraujoch observatory spectrometer using 3 different spectral region

Systematic comparison between the ground based automated Dobson of the Observatory of Haute-Provence and TOMS since 1983

The total ozone quantity has been obtained since September 1983 at O.H.P. using the conventional AD wavelength technique. An average of 180 measurements per year is obtained with the Dobson n deg 85. Each of these daily total quantities is in fact an average of at least 5 measurements. The preliminary comparison with TOMS data show good agreement. We discuss systematic daily and monthly comparisons

Rôle des rétrovirus endogènes humains dans l'inflammation de l'endothélium vasculaire

Le MSRV (Multiple Sclerosis Associated Retro Virus) fait partie de la famille de rétrovirus endogènes humains HERV-W. Une protéine d'enveloppe provenant du MSRV est retrouvée chez la plupart des patients atteints de sclérose en plaque (SEP). Cette protéine (Env-ms) a des propriétés pro-inflammatoires sur les cellules immunitaires et pourrait donc jouer un rôle dans la pathogenèse de la SEP en exacerbant la diapédèse leucocytaire observée dans le système nerveux central (SNC) des patients. Cette étude vise principalement à analyser les effets de Env-ms sur la barrière hémato-encéphalique (BHE) au niveau moléculaire et fonctionnel. Nous avons pu démontrer que l'enveloppe recombinante du MSRV était capable de stimuler plusieurs paramètres inflammatoires sur un modèle humain de BHE in vitro, la lignée HCMEC/D3. En effet, Env-ms induit une surexpression d'ICAM-1, une protéine impliquée dans l'adhésion des leucocytes aux cellules endothéliales, d'une manière dose dépendante ainsi qu'une production dose dépendante de cytokines pro-inflammatoires comme l'IL-6 et l'IL-8. De plus, par une approche utilisant des siRNAs, nous avons pu montrer que Env-ms était reconnue par le récepteur TLR4, un récepteur de l'immunité innée exprimé par les cellules endothéliales. Nous avons aussi montré par des essais fonctionnels que Env-ms stimulait de manière significative l'adhésion de cellules immunitaires activées à la monocouche de cellules endothéliales. Enfin, nous avons aussi mesuré les effets de Env-ms sur des cultures primaires de cellules endothéliales HUVEC et nous avons pu montrer que les propriétés pro-inflammatoires de la protéine d'enveloppe étaient similaires à celles observées sur le modèle HCMEC/D3 Ces résultats appuient l'hypothèse selon laquelle le MSRV pourrait être impliqué dans la pathogenèse de la SEP ou bien dans le maintien d'un niveau d'inflammation élevé favorisant le désordre immunitaire observé chez les patients. Le MSRV pourrait également jouer un rôle dans d'autres maladies inflammatoires chroniques.The MSRV (Multiple Sclerosis Associated Retro Virus) belongs to the human endogenous retrovirus HERV-W family. An envelope protein originating from the MSRV was found in most patients with multiple sclerosis (MS). This protein (Env-ms) has pro-inflammatory properties on several immune cells and could therefore play a role in the MS pathogenesis by promoting the leukocyte diapedesis observed in the central nervous system of patients. Our study aims to analyze the effects of Env-ms on the blood-brain barrier (BBB) at a molecular and functional level. We have demonstrated that the recombinant MSRV envelope was able to strongly stimulate several inflammatory parameters on a human BBB in vitro model, the HCMEC/D3 cell line. Indeed, Env-ms induced overexpression of ICAM-1, a major mediator of leukocyte adhesion to endothelial cells, in a dose-dependent manner and a strong dose-dependent production of the pro-inflammatory cytokines IL-6 and IL-8. Furthermore, using a silencing approach with siRNAs, we have shown that Env-ms was recognized via the TLR4 receptor, a pattern recognition receptor of innate immunity present on endothelial cells. Indeed, the knock down of TLR4 abolishes the pro-inflammatory effects of Env-ms. We have also shown using functionnal assays, that the treatment of brain endothelial cells with Env-ms significantly stimulated the adhesion of activated immune cells to the monolayer of endothelial cells. We also assessed the effects of Env-ms on primary endothelial cells HUVECs and we observed that the pro-inflammatory properties of the envelope protein were similar to those observed on HCMEC/D3. These findings support the hypothesis that MSRV could be involved in the pathogenesis of MS disease or at least in maintenance of inflammatory conditions thus fueling the auto-immune disorder. The MSRV could also play a role in other chronic inflammatory diseases.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

On the feasibility of retrieving 16O 18O 16O ozone from high resolution ground-based FTIR spectra

We present evidence of the 16O 18O 16O ozone isotope in the 5 micron region from FTIR solar occultation spectra obtained from the Jungfraujoch Solar Observatory (47°N, 8°E, 3580 m) in Switzerland at a spectral resolution of 0,0025 cm-1 (res. = 1/2L). These spectra clearly show numerous unblended lines of the 16O 18O 16O ozone isotope. Laboratory spectra in the 5 micron region of 16O 18O 16O have been measured and have yielded line positions of the nu1 + nu3 isotopic bands which can eventually lead to their retrieval from measured ground-based solar occultation spectra

Production of medium chain fatty acid by Yarrowia lipolytica: Combining molecular design and TALEN to engineer the fatty acid synthase

Yarrowia lipolytica is a promising organism for the production of lipids of biotechnological interest and particularly for biofuel. In this study, we engineered lipid biosynthesis through rational engineering of the giant multifunctional Fatty Acid Synthase (FAS) enzyme to modulate fatty acid chain length and produce shorter fatty acids. Based on the hypothesis that the Ketoacyl Synthase (KS) domain, responsible for chain elongation in Yarrowia lipolytica, is directly involved in chain length specificity, a computer-based strategy was undertaken to re-design mutants of the Ketoacyl Synthase. Molecular modelling of this domain in interaction with a C16-acyl substrate enabled identification of a key residue from the fatty acid binding site. This site was then targeted by mutagenesis in order to modify KS fatty acid chain length specificity. To introduce point mutations in this essential gene, we applied, for the first time, the TALEN technology to Yarrowia lipolytica and demonstrated the efficiency of the technique to perform site-directed mutagenesis at a specific genomic locus. Some mutants led to a significant increase of C14 fatty acid. Thanks to the use of an elegant combination of genome editing technology and molecular modelling, this study provides for the first time, evidences that the KS domain of the fungal FASI system is directly involved in fatty acid chain length specificity

Inflammatory response of endothelial cells to a human endogenous retrovirus associated with multiple sclerosis is mediated by TLR4.

The MSRV (multiple sclerosis-associated retrovirus) belongs to the human endogenous retrovirus HERV-W family. The envelope protein originating from the MSRV has been found in most patients with multiple sclerosis (MS). This protein (Env-ms) has pro-inflammatory properties for several types of immune cells and could therefore play a role in MS pathogenesis by promoting the leukocyte diapedesis observed in the central nervous system of patients. Our study aims to analyze the effects of Env-ms on the blood-brain barrier (BBB) at a molecular and functional level. We demonstrate that the recombinant MSRV envelope is able to stimulate several inflammatory parameters in a human BBB in vitro model, the HCMEC/D3 brain endothelial cell line. Indeed, Env-ms induces over-expression of ICAM-1, a major mediator of leukocyte adhesion to endothelial cells, in a dose-dependent manner as well as a strong dose-dependent production of the pro-inflammatory cytokines IL-6 and IL-8. Furthermore, using a silencing approach with siRNAs, we show that Env-ms is recognized via the Toll-like receptor 4 receptor, a pattern recognition receptor of innate immunity present on endothelial cells. We also show, using functional assays, that treatment of brain endothelial cells with Env-ms significantly stimulated the adhesion and the transmigration of activated immune cells through a monolayer of endothelial cells. These findings support the hypothesis that MSRV could be involved in the pathogenesis of MS disease or at least in maintenance of inflammatory conditions, thus fueling the auto-immune disorder. MSRV could also play a role in other chronic inflammatory diseases

Mycoplasma mycoides, from "mycoides Small Colony" to "capri". A microevolutionary perspective

<p>Abstract</p> <p>Background</p> <p>The <it>Mycoplasma mycoides </it>cluster consists of five species or subspecies that are ruminant pathogens. One subspecies, <it>Mycoplasma mycoides </it>subspecies <it>mycoides </it>Small Colony (MmmSC), is the causative agent of contagious bovine pleuropneumonia. Its very close relative, <it>Mycoplasma mycoides </it>subsp. <it>capri </it>(Mmc), is a more ubiquitous pathogen in small ruminants causing mastitis, arthritis, keratitis, pneumonia and septicaemia and is also found as saprophyte in the ear canal. To understand the genetics underlying these phenotypic differences, we compared the MmmSC PG1 type strain genome, which was already available, with the genome of an Mmc field strain (95010) that was sequenced in this study. We also compared the 95010 genome with the recently published genome of another Mmc strain (GM12) to evaluate Mmc strain diversity.</p> <p>Results</p> <p>The MmmSC PG1 genome is 1,212 kbp and that of Mmc 95010 is ca. 58 kbp shorter. Most of the sequences present in PG1 but not 95010 are highly repeated Insertion Sequences (three types of IS) and large duplicated DNA fragments. The 95010 genome contains five types of IS, present in fewer copies than in PG1, and two copies of an integrative conjugative element. These mobile genetic elements have played a key role in genome plasticity, leading to inversions of large DNA fragments. Comparison of the two genomes suggested a marked decay of the PG1 genome that seems to be correlated with a greater number of IS. The repertoire of gene families encoding surface proteins is smaller in PG1. Several genes involved in polysaccharide metabolism and protein degradation are also absent from, or degraded in, PG1.</p> <p>Conclusions</p> <p>The genome of MmmSC PG1 is larger than that of Mmc 95010, its very close relative, but has less coding capacity. This is the result of large genetic rearrangements due to mobile elements that have also led to marked gene decay. This is consistent with a non-adaptative genomic complexity theory, allowing duplications or pseudogenes to be maintained in the absence of adaptive selection that would lead to purifying selection and genome streamlining over longer evolutionary times. These findings also suggest that MmmSC only recently adapted to its bovine host.</p