Direct exoplanet imaging with small-angle Vortex coronagraphs

Vortex coronagraphs are among the most promising solutions to perform high contrast imaging at small angular separations from bright stars. They enhance the dynamic range at very small inner working angle (down to the diffraction limit of the telescope) and provide a clear 360 degree discovery space for high-contrast direct imaging of exoplanets. In this talk, we will report on the first scientific results obtained with Vortex coronagraphs installed on 10-m class telescopes (i.e., the VLT and the LBT) and on the recent installation of one Vortex at Keck. We will describe the in-lab and on-sky performance of the Vortex, and describe the lessons learned after a few years of operation. Finally, we will discuss the prospects of our vortices for future extremely large telescopes and space missions.VORTE

Tetracycline Gene Transfer in Staphylococcus xylosus in situ During Sausage Fermentation

International audienceThe presence of determinants of resistance to antibiotics can constitute a possible safety hazard in coagulase-negative staphylococci (CNS), which are widely present in food of animal origin. Among CNS, S. xylosus is a species frequently isolated from fermented meat products. Resistance to tetracycline was found to be one of the most distributed resistances occurring in S. xylosus strains isolated from fermented sausages. We evaluated the transfer of tetracycline resistance in vitro and in situ between S. xylosus strains. We selected three strains isolated from dry fermented sausages, resistant to tetracycline but not to minocycline, their resistance occurring by a mechanism of active efflux encoded by the tetK gene. Only one strain was able to transfer its tetracycline resistance to a recipient strain initially susceptible and plasmid-free using a filter mating procedure. Transfer of tetracycline resistance was observed at very low frequencies of 3.4 × 10-9 per recipient. To further investigate the transferability of this tetracycline resistance, the donor and recipient strains were tested in pilot-scale fermented sausage production. This transfer was possible but at a low rate, 1.4 × 10-7, and only under conditions of a high inoculation level of 108 CFU/g of meat. The tetK gene is located on a small mobilizable plasmid close to Staphylococcus aureus pT181 plasmid. In conclusion, the transfer of tetracycline resistance between strains of S. xylosus is possible, but at a really low frequency in vitro and in situ in fermented sausages. Even if this represents a very moderate risk, it should be taken into account as required by the European approach of Qualified Presumption of Safety (QPS) and AFSSA safety recommendations, advising that strains used as starter cultures should not carry any transferable antibiotic resistance

Flores protectrices pour la conservation des aliments

Synthèse bibliographique consacrée à l’évaluation de flores protectrices pour améliorer la qualité microbiologique des aliments, cet ouvrage recense les espèces bactériennes et les mécanismes mis en jeu pour lutter contre les flores indésirables, principalement pathogènes. Les critères requis pour la sélection de flores protectrices efficaces ainsi que des exemples dans les principales filières alimentaires sont présentés

Vers une règlementation appropriée des flores protectrices

National audienc

Introduction - La biopréservation et les microorganismes bioprotecteurs

absen

Impact of reducing nitrate/nitrite levels on the behavior of Salmonella Typhimurium and Listeria monocytogenes in French dry fermented sausages

International audienc

Persistence and survival of Campylobacter in turkey and poultry meat after chilling process at slaughterhouse and after refrigerated or frozen storage.

Poste

La connaissance approfondie des communautés bactériennes des aliments et ses conséquences pour l’utilisation de la biopréservation

National audienc

Development of Lactobacillus sakei strain cocktails to improve hygienic quality of raw beef meat products

absen