Analysis of the Legionella longbeachae Genome and Transcriptome Uncovers Unique Strategies to Cause Legionnaires' Disease

Legionella pneumophila and L. longbeachae are two species of a large genus of bacteria that are ubiquitous in nature. L. pneumophila is mainly found in natural and artificial water circuits while L. longbeachae is mainly present in soil. Under the appropriate conditions both species are human pathogens, capable of causing a severe form of pneumonia termed Legionnaires' disease. Here we report the sequencing and analysis of four L. longbeachae genomes, one complete genome sequence of L. longbeachae strain NSW150 serogroup (Sg) 1, and three draft genome sequences another belonging to Sg1 and two to Sg2. The genome organization and gene content of the four L. longbeachae genomes are highly conserved, indicating strong pressure for niche adaptation. Analysis and comparison of L. longbeachae strain NSW150 with L. pneumophila revealed common but also unexpected features specific to this pathogen. The interaction with host cells shows distinct features from L. pneumophila, as L. longbeachae possesses a unique repertoire of putative Dot/Icm type IV secretion system substrates, eukaryotic-like and eukaryotic domain proteins, and encodes additional secretion systems. However, analysis of the ability of a dotA mutant of L. longbeachae NSW150 to replicate in the Acanthamoeba castellanii and in a mouse lung infection model showed that the Dot/Icm type IV secretion system is also essential for the virulence of L. longbeachae. In contrast to L. pneumophila, L. longbeachae does not encode flagella, thereby providing a possible explanation for differences in mouse susceptibility to infection between the two pathogens. Furthermore, transcriptome analysis revealed that L. longbeachae has a less pronounced biphasic life cycle as compared to L. pneumophila, and genome analysis and electron microscopy suggested that L. longbeachae is encapsulated. These species-specific differences may account for the different environmental niches and disease epidemiology of these two Legionella species

Ann Intensive Care

Despite a large body of evidence, the implementation of guidelines on hemodynamic optimization and goal-directed therapy remains limited in daily routine practice. To facilitate/accelerate this implementation, a panel of experts in the field proposes an approach based on six relevant questions/answers that are frequently mentioned by clinicians, using a critical appraisal of the literature and a modified Delphi process. The mean arterial pressure is a major determinant of organ perfusion, so that the authors unanimously recommend not to tolerate absolute values below 65 mmHg during surgery to reduce the risk of postoperative organ dysfunction. Despite well-identified limitations, the authors unanimously propose the use of dynamic indices to rationalize fluid therapy in a large number of patients undergoing non-cardiac surgery, pending the implementation of a "validity criteria checklist" before applying volume expansion. The authors recommend with a good agreement mini- or non-invasive stroke volume/cardiac output monitoring in moderate to high-risk surgical patients to optimize fluid therapy on an individual basis and avoid volume overload. The authors propose to use fluids and vasoconstrictors in combination to achieve optimal blood flow and maintain perfusion pressure above the thresholds considered at risk. Although purchase of disposable sensors and stand-alone monitors will result in additional costs, the authors unanimously acknowledge that there are data strongly suggesting this may be counterbalanced by a sustained reduction in postoperative morbidity and hospital lengths of stay. Beside existing guidelines, knowledge and explicit clinical reasoning tools followed by decision algorithms are mandatory to implement individualized hemodynamic optimization strategies and reduce postoperative morbidity and duration of hospital stay in high-risk surgical patients

Avant-propos

Chalmin Emilie, Dambrine Etienne, David Bernard, Faivre Pierre, Poulenard Jerôme. Avant-propos. In: Collection EDYTEM. Cahiers de géographie, numéro 18, 2015. Sols et matières organiques. Mémoires et héritages. p. 5

Porous silicon membrane, with an integrated aqueous supply, for two chamber AFM

International audienceImaging membrane proteins in aqueous solution in their native configuration remains a challenge for atomic force microscopy (AFM). Usually, supported lipidic bilayer membranes decorated with proteins have been imaged most of the time on mica surfaces. However, for proteic transmembrane structures, the presence of the underlying substrate can be detrimental inducing a denaturation process. In this paper we present a full silicon process enabling the fabrication of free standing suspended lipidic membranes on nanoholes suitable for liquid AFM imaging. A simple microfluidic device gives access to both sides of the membranes enabling dynamical chemical changes to be performed during AFM imaging

Avant-propos

Chalmin Emilie, Dambrine Etienne, David Bernard, Faivre Pierre, Poulenard Jerôme. Avant-propos. In: Collection EDYTEM. Cahiers de géographie, numéro 18, 2015. Sols et matières organiques. Mémoires et héritages. p. 5

Manufacturing and verification of ZnS and Ge prisms for the JWST MIRI imager

The JWST Mid-Infrared Instrument (MIRI) is designed to meet the JWST science requirements for mid-IR capabilities and includes an Imager MIRIM provided by CEA (France). A double-prism assembly (DPA) allows MIRIM to perform low-resolution spectroscopy. The MIRIM DPA shall meet a number of challenging requirements in terms of optical and mechanical constraints, especially severe optical tolerances, limited envelope and very high vibration loads. The University of Cologne (Germany) and the Centre Spatial de Liege (Belgium) are responsible for design, manufacturing, integration, and testing of the prism assembly. A companion paper (Fischer et al. 2008) is presenting the science drivers and mechanical design of the DPA, while this paper is focusing on optical manufacturing and overall verification processes. The first part of this paper describes the manufacturing of Zinc-sulphide and Germanium prisms and techniques to ensure an accurate positioning of the prisms in their holder. (1) The delicate manufacturing of Ge and ZnS materials and (2) the severe specifications on the bearing and optical surfaces flatness and the tolerance on the prism optical angles make this process innovating. The specifications verification is carried out using mechanical and optical measurements; the implemented techniques are described in this paper. The second part concerns the qualification program of the double-prism assembly, including the prisms, the holder and the prisms anti-reflective coatings qualification. Both predictions and actual test results are shown.MIRI for JWS

VUV Optical Ground System Equipment and its application to the ICON FUV flight grating characterization and selection

peer reviewedICON FUV is a two channel spectrographic imager that measures intensity and spatial distribution of oxygen (135.6 nm) and molecular nitrogen (157 nm) of the ionosphere. As those wavelengths are strongly absorbed by the atmosphere, the optical elements of the system have to be tested inside vacuum chambers. Prior to the instrument alignment and calibration, two 3600 gr/mm gratings were characterized. The primary focus is the measurement of the diffraction efficiencies; while the second objective is to select the best grating and to define which is the flight and the spare. A dedicated setup has been developed to assess the grating optical performances under vacuum. A 1 cm diameter collimated beam is generated using an off-axis parabola and a UV source at its focal point. The grating is placed at the center of two rotation stages collinearly aligned. One detector is placed on a rotating arm, deported from its rotation center. A PMT detector records diffracted light intensity with respect to its angular position and its wavelength. Angular incidence on the grating is tuned with the help of the second rotation stage. The grating efficiency homogeneity and scattering properties are measured through a Y-X scan

Alignment and calibration of the ICON-FUV instrument: Development of a vacuum UV facility

peer reviewedThe optical calibration of the ICON-FUV instrument requires designing specific ground support equipment (GSE). The ICON-FUV instrument is a spectrographic imager that operates on two specific wavelengths in the UV (135.6 nm and 157 nm). All the operations have to be performed under vacuum UV light. The optical setup is based on a VUV monochromator coupled with a collimator that illuminates the FUV entrance slit. The instrument is placed on a manipulator providing fields pointing. Image quality and spectral properties can be then characterized for each field. OGSE, MGSE, optical calibration plan and vacuum alignment of the instrument are described

Introduction. La géochimie organique des sols et des sédiments : une clé pour décrire l’anthropocène ?

This article aims to introduce the research presented in this volume of the Collection EDYTEM. The different papers come from a common scientific meeting between soil scientists of the French Soil Science Society (AFES) and organic geochemists of FROG. These articles seem to indicate a renewal of the approaches, issues and methods of study on the evolution of soil linked with human activities. Soil geochemistry and sediments (particularly organic geochemistry) appears as an indispensable tool to reveal the history of soil and human practices in the Anthropocene.Le présent article se propose de mettre en perspective les travaux de recherche présentés dans ce volume de la Collection EDYTEM. Fruit d’une rencontre scientifique entre pédologues de l’AFES et géochimistes de FROG, ces articles nous semblent témoigner d’un renouveau des approches, des questions et des méthodes d’étude sur l’évolution des sols en lien avec les activités humaines. La géochimie des sols et des sédiments (en particulier la géochimie organique) nous apparaît comme un outil indispensable pour révéler l’histoire des sols et des pratiques humaines à l’Anthropocène.Poulenard Jerôme, Arnaud Fabien, Perrette Yves, Sabatier Pierre, Deline Philip, Giguet-Covex Charline, Bajard Manon, Mourier Brice, Quiers Marine, Malet Emmanuel, Pignol Cécile, Develle Anne-Lise, Fanget Bernard, Dambrine Etienne, Faivre Pierre, Chalmin Emilie. Introduction. La géochimie organique des sols et des sédiments : une clé pour décrire l’anthropocène ?. In: Collection EDYTEM. Cahiers de géographie, numéro 18, 2015. Sols et matières organiques. Mémoires et héritages. pp. 9-18