Mass Spectrometry-Based Metabolomics to Elucidate Functions in Marine Organisms and Ecosystems

Marine systems are very diverse and recognized as being sources of a wide range of biomolecules. This review provides an overview of metabolite profiling based on mass spectrometry (MS) approaches in marine organisms and their environments, focusing on recent advances in the field. We also point out some of the technical challenges that need to be overcome in order to increase applications of metabolomics in marine systems, including extraction of chemical compounds from different matrices and data management. Metabolites being important links between genotype and phenotype, we describe added value provided by integration of data from metabolite profiling with other layers of omics, as well as their importance for the development of systems biology approaches in marine systems to study several biological processes, and to analyze interactions between organisms within communities. The growing importance of MS-based metabolomics in chemical ecology studies in marine ecosystems is also illustrated

Are two better than one? Analysis of an FtsK/Xer recombination system that uses a single recombinase

Bacteria harbouring circular chromosomes have a Xer site-specific recombination system that resolves chromosome dimers at division. In Escherichia coli, the activity of the XerCD/dif system is controlled and coupled with cell division by the FtsK DNA translocase. Most Xer systems, as XerCD/dif, include two different recombinases. However, some, as the Lactococcus lactis XerS/difSL system, include only one recombinase. We investigated the functional effects of this difference by studying the XerS/difSL system. XerS bound and recombined difSL sites in vitro, both activities displaying asymmetric characteristics. Resolution of chromosome dimers by XerS/difSL required translocation by division septum-borne FtsK. The translocase domain of L. lactis FtsK supported recombination by XerCD/dif, just as E. coli FtsK supports recombination by XerS/difSL. Thus, the FtsK-dependent coupling of chromosome segregation with cell division extends to non-rod-shaped bacteria and outside the phylum Proteobacteria. Both the XerCD/dif and XerS/difSL recombination systems require the control activities of the FtsKγ subdomain. However, FtsKγ activates recombination through different mechanisms in these two Xer systems. We show that FtsKγ alone activates XerCD/dif recombination. In contrast, both FtsKγ and the translocation motor are required to activate XerS/difSL recombination. These findings have implications for the mechanisms by which FtsK activates recombination

Régulation de l'inflammation au cours des phases précoces des infections VIH-1/SIV chez les progresseurs lents ou non progresseurs

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Dialogue à propos de l'ouvrage 'Usagers de drogues et Justice pénale. Constructions et expériences' de MS Devresse

Depuis le début des années 90, le traitement judiciaire des usagers de drogues, figures cibles des politiques pénales et sécuritaires belges et européennes, s’est profondément modifié. Cette transformation constitue le point de départ de cet ouvrage qui s’attache à en mettre en lumière l’ambiguïté déduite d’un double mouvement. D’une part, des procédures pénales dites « alternatives » placent l’usager de drogues au centre d’un régime marqué par des formes de négociation et de subjectivation ; d’autre part, l’on applique à ce même usager des procédés bio-technologiques -comme le recours accru aux tests toxicologiques- qui semblent, eux, davantage relever d’une logique d’objectivation et de pure contrainte. Cet ouvrage propose une lecture originale des conséquences de cette association subjectivation/objectivation tant sur la trajectoire judiciaire des usagers de drogues que sur leur appréhension de la justice pénale. En effet, le point de vue adopté sera celui des usagers rencontrés et interrogés dans le cadre d’une recherche empirique explorant également l’activité des instances policières et judiciaires. Les aspects relatifs à cette expérience des usagers illustrent le fonctionnement actuel de la justice pénale, ses transformations, mais aussi ses dysfonctionnements et ses paradoxes. La complexité, l’opacité de la procédure judiciaire, le rôle ambigu de ses acteurs, la difficulté de mettre en place les conditions d’une véritable communication entre les professionnels et le justiciable sont ici éclairés par la présentation du point de vue des consommateurs de drogues, mais également la mise à plat de leurs trajectoires, de leurs stratégies et de leur représentation de la justice

Returns of impressionist, modern and contemporary European painters, 1962-1991

info:eu-repo/semantics/publishe

Returns of Impressionist, Modern and Contemporary European Paintings 1962-1991

We construct returns and quantity indices for Impressionist, Modern and Contemporary painting over the last thirty years, using the results of public auctions. In particular, we isolate the large swing in prices during the late 1980s; from results on individual artists, we also conclude that the randomness in the behaviour of prices is very limited, once the behaviour of the aggregate market in known.

Validation of CFD simulations of the flow around a full-scale rowing blade with realistic kinematics

International audienceThis article deals with the validation of the modelling and numerical simulation of a rowing stroke, by means of CFD. Simplified but realistic strokes were performed in a towing tank with a rotating arm and a real flexible oar. Those laboratory conditions are better controlled than those of in situ trials. An FSI procedure is developed to take into account the oar bending, which is essential in the physics of this flow. The results show that this numerical framework is able to reproduce qualitatively the real flow including the breaking of the free surface around the blade and the transport of the air cavity behind it. The profiles of forces are well reproduced, with propulsive forces overestimated by 5-12% for their maxima. The study also focuses on the computation of the uncertainties. It is highlighted that, even for this well-controlled experimental equipment, the uncertainties on the quantities of interest are of about 11%. In other words, the experimental uncertainty covers the numerical errors. So, this numerical modelling is validated and can be used for design and optimisation of blades and oars, or to contribute to the better understanding of the boat-oar-rower system and its dynamics

Desorption of Cs from vermiculite by ultrasound assisted ion exchange

International audienc