Adaptation de la fonction de transport de l'oxygene par l'hemocyanine en milieu hypoxique : etude chez la crevette Penaeus japonicus et chez le crabe Carcinus maenas

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Vampire Blood: Respiratory Physiology of the Vampire Squid (Cephalopoda: Vampyromorpha) in Relation to the Oxygen Minimum Layer

The functional properties of the haemocyanin ofVampyroteuthis infernalis (Cephalopoda: Vampyromorpha), measured at 5 °C, are reported and discussed in relation to hypoxia. The oxygen affinity of this haemocyanin (P50=0.47−0.55 kPa) is higher than any previously measured for a cephalopod. The high cooperativity (n50=2.20−2.23) and Bohr coefficient (−0.22) suggest a true transport function for this haemocyanin. This high-affinity haemocyanin, in conjunction with moderate gill diffusion capacity, provides a sufficient oxygen gradient from the environment to the blood to support the low routine oxygen consumption rate of V. infernali

A New Barrier to Dispersal Trapped Old Genetic Clines That Escaped the Easter Microplate Tension Zone of the Pacific Vent Mussels

Comparative phylogeography of deep-sea hydrothermal vent species has uncovered several genetic breaks between populations inhabiting northern and southern latitudes of the East Pacific Rise. However, the geographic width and position of genetic clines are variable among species. In this report, we further characterize the position and strength of barriers to gene flow between populations of the deep-sea vent mussel Bathymodiolus thermophilus. Eight allozyme loci and DNA sequences of four nuclear genes were added to previously published sequences of the cytochrome c oxidase subunit I gene. Our data confirm the presence of two barriers to gene flow, one located at the Easter Microplate (between 21 degrees 33'S and 31 degrees S) recently described as a hybrid zone, and the second positioned between 7 degrees 25'S and 14 degrees S with each affecting different loci. Coalescence analysis indicates a single vicariant event at the origin of divergence between clades for all nuclear loci, although the clines are now spatially discordant. We thus hypothesize that the Easter Microplate barrier has recently been relaxed after a long period of isolation and that some genetic clines have escaped the barrier and moved northward where they have subsequently been trapped by a reinforcing barrier to gene flow between 7 degrees 25'S and 14 degrees S

Origin and Therapies of Osteosarcoma

Osteosarcoma (OS) is the most frequent primary bone tumor, mainly affecting children and young adults. Despite therapeutic advances, the 5-year survival rate is 70% but drastically decreases to 20–30% for poor responders to therapies or for patients with metastasis. No real evolution of the survival rates has been observed for four decades, explained by poor knowledge of the origin, difficulties related to diagnosis and the lack of targeted therapies for this pediatric tumor. This review will describe a non-exhaustive overview of osteosarcoma disease from a clinical and biological point of view, describing the origin, diagnosis and therapies

Determination of reduced sulfur compounds by high-performance liquid chromatography in hydrothermal seawater and body fluids from Riftia pachyptila

This paper describes a method for the determination of reduced sulfur compounds in hydrothermal seawater and body fluids from the hydrothermal tube worm Riftia pachyptila. Sulfur is a hey component of the hydrothermal ecosystem based on chemosynthesis, Sulfur compounds were derivatized at pH 8 (4.3 for sulfide in biological fluid) with a fluorescent reagent, monobromobimane, and separated by reverse-phase HPLC. The eluted compounds were detected by spectrofluorimetry. This method allowed: the quantitative analysis of sulfide, sulfite, thiosulfate, cysteine and glutathione in seawater, vascular blood and coelomic fluids from R, pachyptila, The detection limits were in the 0.1 mu mol l(-1) range with a precision lower than 10%, The method has been applied to hydrothermal seawater. The organisms are distributed along a gradient of sulfide (produced by the vent) and thiosulfate. Analysis of biological fluid was performed with a new sample treatment allowing the analysis of total sulfide (free and bound to haemoglobin) with results comparable to published methods

Relevance of the stochastic stratigraphic well correlation approach for the study of complex carbonate settings: application to the Malampaya buildup (Offshore Palawan, Philippines)

International audienceThe stochastic stratigraphic well correlation method considers the stratigraphic correlation of well data as a set of possible models to sample and manage uncertainty in subsurface studies. This method addresses the incompleteness of typical subsurface data such as limited seismic resolution, seismic blindness due to the lack of impedance contrast between distinct stratigraphic formations, borehole preferential location. The stochastic stratigraphic well correlation method is applied to the Malampaya buildup (a well documented offshore gas field located NorthWest of the Palawan Island, Philippines), aged upper Eocene to lower Miocene, and developed on the crest of a tilt-block. Among the available data, ten wells, seven of which are cored, have been drilled and a high resolution 3D seismic survey was acquired by Shell Philippines in 2002

Global host molecular perturbations upon in situ loss of bacterial endosymbionts in the deep-sea mussel Bathymodiolus azoricus assessed using proteomics and transcriptomics

Background: Colonization of deep-sea hydrothermal vents by most invertebrates was made efficient through their adaptation to a symbiotic lifestyle with chemosynthetic bacteria, the primary producers in these ecosystems. Anatomical adaptations such as the establishment of specialized cells or organs have been evidenced in numerous deep-sea invertebrates. However, very few studies detailed global inter-dependencies between host and symbionts in these ecosystems. In this study, we proposed to describe, using a proteo-transcriptomic approach, the effects of symbionts loss on the deep-sea mussel Bathymodiolus azoricus' molecular biology. We induced an in situ depletion of symbionts and compared the proteo-transcriptome of the gills of mussels in three conditions: symbiotic mussels (natural population), symbiont-depleted mussels and aposymbiotic mussels. Results: Global proteomic and transcriptomic results evidenced a global disruption of host machinery in aposymbiotic organisms. We observed that the total number of proteins identified decreased from 1118 in symbiotic mussels to 790 in partially depleted mussels and 761 in aposymbiotic mussels. Using microarrays we identified 4300 transcripts differentially expressed between symbiont-depleted and symbiotic mussels. Among these transcripts, 799 were found differentially expressed in aposymbiotic mussels and almost twice as many in symbiont-depleted mussels as compared to symbiotic mussels. Regarding apoptotic and immune system processes - known to be largely involved in symbiotic interactions - an overall up-regulation of associated proteins and transcripts was observed in symbiont-depleted mussels. Conclusion: Overall, our study showed a global impairment of host machinery and an activation of both the immune and apoptotic system following symbiont-depletion. One of the main assumptions is the involvement of symbiotic bacteria in the inhibition and regulation of immune and apoptotic systems. As such, symbiotic bacteria may increase their lifespan in gill cells while managing the defense of the holobiont against putative pathogens

Comparative studies of a high resolution sampling of the different facies of the organic-rich Orbagnoux Deposit (upper Kimmeridgian, Jura); petrographic and bulk geochemical approach; extent and origin of interfacies and intrafacies variations

A large set of high resolution samples (thickness down to a few millimetres), corresponding to the five facies of the Orbagnoux deposit, were examined for their compositional (major and trace elements, organic matter (OM) content), petrographic (transmitted-and reflected-light microscopy, scanning and transmission electron microscopy), pyrolytic (Rock-Eval, Geoelf Sulphur Analyser and Pyromat pyrolyses) and spectroscopic (Fourier transform infrared) features. A number of similarities were thus observed although, as previously shown, the formation of the light undulated laminae was associated with the development of cyanobacterial mats on sediment surface, whereas the other four facies originated from coccolith settling. Nevertheless, three substantial differences were also noted :- Lower OM contents in the light undulated laminae likely due to the extensive mineralization of mat biomass before sulphurization. - Relatively less reducing conditions during the deposition of the light undulated laminae and massive limestones. - Large semi-quantitative differences in FTIR spectra (the kerogens from the dark-coloured samples tend to be richer in C = O groups while those from the light-coloured ones tend to be richer in OH groups and C = C bonds). Furthermore, the FTIR spectra show, for each facies, large intrafacies differences that may reflect, in part, differences in the degree of post-depositional oxidative alteration during emergences

100 W-level peak power laser system tunable in the LWIR applied to detection of persistent chemical agents

Through the European Defence Agency, the Joint Investment Programme on CBRN protection funded the project AMURFOCAL to address detection at stand-off distances with amplified quantum cascade laser technology in the longwave infrared spectral range, where chemical agents have specific absorptions features. An instrument was developed based on infrared backscattering spectroscopy. We realized a pulsed laser system with a fast tunability from 8 to 10 μm using an external-cavity quantum cascade laser (EC-QCL) and optical parametric amplification (OPA). The EC-QCL is tunable from 8 to 10 μm and delivers output peak powers up to 500 mW. The peak power is amplified with high gain in an orientation-patterned gallium arsenide (OP-GaAs) nonlinear crystal. We developed a pulsed fiber laser acousto-optically tunable from 1880 to 1980 nm with output peak powers up to 7 kW as pump source to realize an efficient quasi-phase matched OPA without any mechanical or thermal action onto the nonlinear crystal. Mixing the EC-QCL and the pump beams within the OP-GaAs crystal and tuning the pump wavelength enables parametric amplification of the EC-QCL from 8 to 10 μm leading to up to 120 W peak power. The output is transmitted to a target at a distance of 10 – 20 m. A receiver based on a broadband infrared detector comprises a few detector elements. A 3D data cube is registered by wavelength tuning the laser emission while recording a synchronized signal received from the target. The presentation will describe the AMURFOCAL instrument, its functional units and its principles of operation

Active multispectral reflection fingerprinting of persistent chemical agents

Remote detection of toxic chemicals of very low vapour pressure deposited on surfaces in form of liquid films, droplets or powder is a capability that is needed to protect operators and equipment in chemical warfare scenarios and in industrial environments. Infrared spectroscopy is a suitable means to support this requirement. Available instruments based on passive emission spectroscopy have difficulties in discriminating the infrared emission spectrum of the surface background from that of the contamination. Separation of background and contamination is eased by illuminating the surface with a spectrally tuneable light source and by analyzing the reflectivity spectrum. The project AMURFOCAL (Active Multispectral Reflection Fingerprinting of Persistent Chemical Agents) has the research topic of stand-off detection and identification of chemical warfare agents (CWAs) with amplified quantum cascade laser technology in the long-wave infrared spectral range. The project was conducted under the Joint Investment Programme (JIP) on CBRN protection funded through the European Defence Agency (EDA). The AMURFOCAL instrument comprises a spectrally narrow tuneable light source with a broadband infrared detectorand chemometric data analysis software. The light source combines an external cavity quantum cascade laser (EC-QCL) with an optical parametric amplifier (OPA) to boost the peak output power of a short laser pulse tuneable over the infrared fingerprint region. The laser beam is focused onto a target at a distance between 10 and 20 m. A 3D data cube is registered by tuning the wavelength of the laser emission while recording the received signal scattered off the target using a multi-element infrared detector. A particular chemical is identified through the extraction of its characteristics pectral fingerprint out of the measured data. The paper describes the AMURFOCAL instrument, its functional units, and its principles of operation