Potential alteration of U37K' paleothermometer due to selective degradation of alkenones by marine bacteria isolated from the haptophyte Emiliania huxleyi.

The unsaturation ratio of C(37) alkenones (U(37)(K')) produced by haptophyte microalgae such as Emiliania huxleyi is often used as proxy for past sea surface temperature. In this study, 29 bacterial strains were isolated from cultures of the strain E. huxleyi TWP1.

Phytoplankton distribution during two contrasted summers in a Mediterranean harbour: combining automated submersible flow cytometry with conventional techniques.

Automated in situ flow cytometry, high-pressure liquid chromatography (HPLC), optical microscopy and fluorometry were combined to monitor phytoplankton over two summer periods (2005 and 2006). In 2006, temperature was higher and nutrients lower than in 2005, generating differences in the phytoplankton assemblages (i.e.

Isolation of hydrocarbon-degrading extremely halophilic archaea from an uncontaminated hypersaline pond (Camargue, France).

Little information exists about the ability of halophilic archaea present in hypersaline environments to degrade hydrocarbons. In order to identify the potential actors of hydrocarbon degradation in these environments, enrichment cultures were prepared using samples collected from a shallow crystallizer pond with no known contamination history in Camargue, France, with n-alkanes provided as source of carbon and energy. Five alkane-degrading halophilic archaeal strains were isolated: one (strain MSNC 2) was closely related to Haloarcula and three (strains MSNC 4, MSNC 14, and MSNC 16) to Haloferax.

Genetic survey of shallow populations of the Mediterranean red coral [Corallium rubrum (Linnaeus, 1758)]: new insights into evolutionary processes shaping nuclear diversity and implications for conservation.

Combined action from over-harvesting and recent mass mortality events potentially linked to ongoing climate changes has led to new concerns for the conservation of shallow populations (5-60 m) of Corallium rubrum, an octocorallian that is mainly found in the Mediterranean Sea. The present study was designed to analyse population structure and relationships at different spatial scales (from 10s of meters to 100s of kilometres) with a focus on dispersal pattern. We also performed the first analysis of the distribution of genetic diversity using a comparative approach between regional-clusters and samples.

Man induced change in community control in the north-western Black Sea: The top-down bottom-up balance.

The present study shows how marine commercial fish food webs dramatically changed in the north-western Black Sea on both pelagic and benthic environments. Fisheries landings, diversity and equitability strongly decreased between 1965-1970 and 2001-2005. Fishes adapted their feeding behaviour to the increasingly low species diversity of the Black Sea communities.

Climate change effects on a miniature ocean: the highly diverse, highly impacted Mediterranean Sea.

Little doubt is left that climate change is underway, strongly affecting the Earth's biodiversity. Some of the greatest challenges ahead concern the marine realm, but it is unclear to what extent changes will affect marine ecosystems. The Mediterranean Sea could give us some of the answers.

Utilization of a submersible UV fluorometer for monitoring anthropogenic inputs in the Mediterranean coastal waters.

We evaluated the performances of a submersible ultraviolet fluorometer (EnviroFlu-HC, TriOS Optical Sensors) dedicated to the real time measurement of polycyclic aromatic hydrocarbons (PAHs) in the aquatic media. We conducted calibration experiments and in situ measurements in the coastal Mediterranean Sea. We found that the EnviroFlu-HC was not strictly specific to PAHs, even though it exhibited the highest sensitivity for phenanthrene, but could response to tryptophan-like material as well, and in a much less extent, to humic substances.

Isolation of alkane-degrading bacteria from deep-sea Mediterranean sediments.

Aims: To isolate and identify alkane-degrading bacteria from deep-sea superficial sediments sampled at a north-western Mediterranean station.

Methods And Results: Sediments from the water/sediment interface at a 2400 m depth were sampled with a multicorer at the ANTARES site off the French Mediterranean coast and were promptly enriched with Maya crude oil as the sole source of carbon and energy. Alkane-degrading bacteria belonging to the genera Alcanivorax, Pseudomonas, Marinobacter, Rhodococcus and Clavibacter-like were isolated, indicating that the same groups were potentially involved in hydrocarbon biodegradation in deep sea as in coastal waters.

Determination of lipid degradation by marine lipase-producing bacteria: critical evaluation of lipase activity assays.

With the aim of obtaining a better understanding of lipids-lipases interactions in bacterioplankton communities in oceans, we used different methods for measuring lipase activities in pure cultures of the marine strain Alteromonas macleodii. The decay of tripalmitate added to cultures was followed chemically over time. In an enzymatic approach, lipase activities were measured using the fluorogenic lipid analogs MUF-palmitate and ELF-palmitate.

Origin and evolution of the Notch signalling pathway: an overview from eukaryotic genomes.

Background: Of the 20 or so signal transduction pathways that orchestrate cell-cell interactions in metazoans, seven are involved during development. One of these is the Notch signalling pathway which regulates cellular identity, proliferation, differentiation and apoptosis via the developmental processes of lateral inhibition and boundary induction. In light of this essential role played in metazoan development, we surveyed a wide range of eukaryotic genomes to determine the origin and evolution of the components and auxiliary factors that compose and modulate this pathway.

Double bond migration to methylidene positions during electron ionization mass spectrometry of branched monounsaturated fatty acid derivatives.

Electron ionization mass spectra of several monounsaturated methyl-branched fatty acid methyl and trimethylsilyl esters were examined. These spectra exhibited some intensive fragment ions, whose formation could be explained after double-bond migration to methylidene position. This preferential migration (substantiated by deuterium labeling) acts significantly in the case of monounsaturated fatty acid methyl and trimethylsilyl esters possessing a methyl branch localized between the penultimate and the C(4) positions (relative to the ester group), whatever the position of the double-bond.

Origin of the neuro-sensory system: new and expected insights from sponges.

The capacity of all cells to respond to stimuli implies the conduction of information at least over short distances. In multicellular organisms, more complex systems of integration and coordination of activities are necessary. In most animals, the processing of information is performed by a nervous system.

Spatial patterns in PCBs, pesticides, mercury and cadmium in the common sole in the NW Mediterranean Sea, and a novel use of contaminants as biomarkers.

We assessed spatial patterns in 37 PCB congeners, eight pesticides, and the heavy metals mercury and cadmium in the flatfish Solea solea at four sites in the Gulf of Lions (NW Mediterranean). Overall contaminant concentrations generally exceeded those reported for S. solea elsewhere, but fell into the range of other Gulf fishes, testifying of a relatively high contaminant load of this area.

Thalassobaculum salexigens sp. nov., a new member of the family Rhodospirillaceae from the NW Mediterranean Sea, and emended description of the genus Thalassobaculum.

A novel Gram-negative bacteria, named CZ41_10a(T), was isolated from coastal surface waters of the north-western Mediterranean Sea. Cells were motile, pleomorphic rods, 1.6 mum long and 0.

WNT/beta-catenin signalling and epithelial patterning in the homoscleromorph sponge Oscarella.

Sponges branch basally in the metazoan phylogenetic tree and are thus well positioned to provide insights into the evolution of mechanisms controlling animal development, likely to remain active in adult sponges. Of the four sponge clades, the Homoscleromorpha are of particular interest as they alone show the "true" epithelial organization seen in other metazoan phyla (the Eumetazoa). We have examined the deployment in sponges of Wnt signalling pathway components, since this pathway is an important regulator of many developmental patterning processes.

Difference of mercury bioaccumulation in red mullets from the north-western Mediterranean and Black seas.

The relationships between total mercury (Hg) concentration and stable nitrogen isotope ratio (delta(15)N) were evaluated in Mullus barbatus barbatus and M. surmuletus from the Mediterranean Sea and M. barbatus ponticus from the Black Sea.

The Homoscleromorph sponge Oscarella lobularis, a promising sponge model in evolutionary and developmental biology: model sponge Oscarella lobularis.

Sponges branch basally in the metazoan phylogenetic tree and are believed to be composed of four distinct lineages with still uncertain relationships. Indeed, some molecular studies propose that Homoscleromorpha may be a fourth Sponge lineage, distinct from Demospongiae in which they were traditionally classified. They harbour many features that distinguish them from other sponges and are more evocative of those of the eumetazoans.

Careful with understudied phyla: the case of chaetognath.

Background: A recent study by Barthélémy et al. described a set of ribosomal protein (RP) genes extracted from a collection of expressed sequence tags (ESTs) of the chaetognath (arrow worm) Spadella cephaloptera. Three main conclusions were drawn in this paper.

Physiological alteration of the marine bacterium Vibrio angustum S14 exposed to simulated sunlight during growth.

Growth experiments on the marine bacterium Vibrio angustum S14 were conducted under four light conditions using a solar simulator: visible light (V), V + ultraviolet A (UV-A), V + UV-A + UV-B radiation, and dark. Growth was inhibited mainly by UV-B and slightly by UV-A. UV-B radiation induced filaments containing multiple genome copies with low cyclobutane pyrimidine dimers.

NK homeobox genes with choanocyte-specific expression in homoscleromorph sponges.

Data on nonbilaterian animals (sponges, cnidarians, and ctenophores) have suggested that Antennapedia (ANTP) class homeobox genes played a crucial role in the early diversification of animal body plans. Estimates of ancestral gene diversity within this important class of developmental regulators have been mostly based on recent analyses of the complete genome of a demosponge species, leading to the proposal that all ANTP families found in nonsponges animals (eumetazoans) derived from an ancestral "proto-NK" six-gene cluster. However, a single sponge species cannot reveal ancestral metazoan traits, in particular because lineage-specific gene duplications or losses are likely to have occurred during the long history of the Porifera.

Pleistocene separation of mitochondrial lineages of Mytilus spp. mussels from Northern and Southern Hemispheres and strong genetic differentiation among southern populations.

Smooth-shelled mussels, Mytilus spp., have an antitropical distribution. In the Northern Hemisphere, the M.

A method for analysing phosphatase activity in aquatic bacteria at the single cell level using flow cytometry.

It has been demonstrated that ELF97-phosphate (ELF-P) is a useful tool to detect and quantify phosphatase activity of phytoplankton populations at a single cell level. Recently, it has been successfully applied to marine heterotrophic bacteria in culture samples, the cells exhibiting phosphatase activity being detected using epifluorescence microscopy. Here, we describe a new protocol that enables the detection of ELF alcohol (ELFA), the product of ELF-P hydrolysis, allowing the detection of phosphatase positive bacteria, using flow cytometry.

Optical Algorithms at Satellite Wavelengths for Total Suspended Matter in Tropical Coastal Waters.

Is it possible to derive accurately Total Suspended Matter concentration or its proxy, turbidity, from remote sensing data in tropical coastal lagoon waters? To investigate this question, hyperspectral remote sensing reflectance, turbidity and chlorophyll pigment concentration were measured in three coral reef lagoons. The three sites enabled us to get data over very diverse environments: oligotrophic and sediment-poor waters in the southwest lagoon of New Caledonia, eutrophic waters in the Cienfuegos Bay (Cuba), and sediment-rich waters in the Laucala Bay (Fiji). In this paper, optical algorithms for turbidity are presented per site based on 113 stations in New Caledonia, 24 stations in Cuba and 56 stations in Fiji.

Erythropsidinium (Gymnodiniales, Dinophyceae) in the Pacific Ocean, a unique dinoflagellate with an ocelloid and a piston.

The distribution and morphology of the dinoflagellate Erythropsidinium (=Erythropsis) was studied in the vicinity of the Kuroshio and Oyashio Currents, the Philippine, Celebes, Sulu and South China Seas, western and central equatorial and southeast Pacific Ocean. Ninety-four specimens were observed, most of them collected from depths of less than 90m. The highest abundance (15cellsL(-1)) was recorded in the north Philippine Sea in May (32 degrees N, 138 degrees E, 30-m depth).

Chaetognath transcriptome reveals ancestral and unique features among bilaterians.

Background: The chaetognaths (arrow worms) have puzzled zoologists for years because of their astonishing morphological and developmental characteristics. Despite their deuterostome-like development, phylogenomic studies recently positioned the chaetognath phylum in protostomes, most likely in an early branching. This key phylogenetic position and the peculiar characteristics of chaetognaths prompted further investigation of their genomic features.