Common evolutionary origin of planktonic and benthic nitrogen-fixing oscillatoriacean cyanobacteria from tropical oceans

The filamentous cyanobacteria belonging to the genus Hydrocoleum (Blennothrix) are among the most common mat-forming cyanobacteria in tropical oceans. We present here the evidence that these benthic cyanobacteria are morphologically and phylogenetically very close to the planktonic species of Trichodesmium. Genetic relationship was established independently with regard to sequences of the 16S rRNA gene, nifH gene, and phycocyanin and phycoerythrin intergenic spacers. The species of both genera formed a common distinct branch in phylogenetically reconstructed cyanobacterial trees, suggesting that the main constituents of cyanobacterial benthos and plankton have an early common origin and both represent major contributors to nitrogen budget of tropical oceans today as in the distant geological past

European Collaboration in Ocean Cores Science: roots, highlights, off-springs and vision

July 4th, 1947, exactly 75 years after the legendary cruise of H.M.S. Challenger and at a time when ocean science seemed to definitively shift to the shores of Massachusetts and California, the Swedish 5-masted schooner and school-ship Albatross set sail from Göteborg for a 15-months ambitious voyage of circumnavigation of the world oceans. Staffed with cadets and scientists and headed by Hans Pettersson, the Albatross had on board a revolutionary tool: Kullenberg’s piston corer, a 30m-long device which had already allowed the recovery of a 20m-long sediment core. Previously, the Meteor had recovered cores of a maximal length of 0.90m (1925), while in the thirties C.S. Piggot of the Carnegie Institution had “shot” cores up to 3m length in the North-Atlantic with a gun-like device. Sedimentological, geochemical, mineralogical, micropalaeontological analyses and radio-active dating would be carried out not only in Swedish institutes, but also in Vienna, Göttingen, Hanover, Wageningen, Ghent, Paris, London and La Jolla, in the true spirit of the data exploitation scheme which had shaped the success of the cruise of the Challenger. The stage was set for palaeo-environmental research on long sediment cores, archives of past climate and oceans.In the mid-sixties, ocean cores science takes a giant leap with the Deep Sea Drilling Program (DSDP). 20 years after the Albatross, in the fall of 1968, the Glomar Challenger sails from Dakar for the South Atlantic to verify the hypothesis of seafloor spreading and plate tectonics. Europe would join the Ocean Drilling Program (ODP), which set sail in 1984, subsequent to the International Phase of Ocean Drilling (IPOD, 1975-1983). For the first time, the European Science Foundation moves in, providing to numerous smaller European partners a platform of participation in ODP through ECOD, the European Consortium for Ocean Drilling.Some 50 years after the Albatross, the ‘Calypso’ piston corer on board of R/V Marion Dufresne would set the record of piston coring length, with an unrivaled core of over 64m length. The IMAGES programme would boost palaeoclimate research worldwide.At the turn of the century, ECORD - an off-spring of ECOD which had left the parental house - took the lead of the Mission Specific Platform (MSP) scheme in the Integrated Ocean Drilling Program (IODP), pushing frontiers of ocean drilling to extreme environments such as the poles and coral reefs. While not directly involved in the operational aspects, ESF soon took a prominent place in the supporting science, not the least through the EUROCORES programme and research networks.At the onset of the 21st century, while IODP and the international ocean drilling and coring community define a new strategy for post-2013 ocean coring science, Europe moves in with a new revolutionary tool, the MeBo (Meeresboden Bohrgerät), a remotely operated seabed drilling tool capable of drilling and coring from a variety of large vessels. EUROFLEETS provides new opportunities for coordinated naval operations for ocean science. And in parallel, Europe develops the plans for an ambitious drilling platform for the Arctic: Aurora Borealis.Any lucid vision on the future of Ocean Cores Science, which plays a key role in the unraveling of the dynamics of our planet, will build upon the lessons of the past, reflect upon the strengths and weaknesses of the present, and ride upon the excitement of Europe’s young generation, driver of the future

Reef response to sea-level and environmental changes during the last deglaciation: Integrated Ocean Drilling Program Expedition 310, Tahiti Sea Level

The last deglaciation is characterized by a rapid sea-level rise and coeval abrupt environmental changes. The Barbados coral reef record suggests that this period has been punctuated by two brief intervals of accelerated melting (meltwater pulses, MWP), occurring at 14.08-13.61 ka and 11.4-11.1 ka (calendar years before present), that are superimposed on a smooth and continuous rise of sea level. Although their timing, magnitude, and even existence have been debated, those catastrophic sea-level rises are thought to have induced distinct reef drowning events. The reef response to sea-level and environmental changes during the last deglacial sea-level rise at Tahiti is reconstructed based on a chronological, sedimentological, and paleobiological study of cores drilled through the relict reef features on the modern forereef slopes during the Integrated Ocean Drilling Program Expedition 310, complemented by results on previous cores drilled through the Papeete reef. Reefs accreted continuously between 16 and 10 ka, mostly through aggradational processes, at growth rates averaging 10 mm yr-1. No cessation of reef growth, even temporary, has been evidenced during this period at Tahiti. Changes in the composition of coralgal assemblages coincide with abrupt variations in reef growth rates and characterize the response of the upward-growing reef pile to nonmonotonous sea-level rise and coeval environmental changes. The sea-level jump during MWP 1A, 16 ± 2 m of magnitude in ~350 yr, induced the retrogradation of shallow-water coral assemblages, gradual deepening, and incipient reef drowning. The Tahiti reef record does not support the occurrence of an abrupt reef drowning event coinciding with a sea-level pulse of ~15 m, and implies an apparent rise of 40 mm yr-1 during the time interval corresponding to MWP 1B at Barbados. © 2012 Geological Society of America

Effect of antiplatelet agents on Escherichia coli sepsis mechanisms: A review

Despite ever-increasing improvements in the prognosis of sepsis, this condition remains a frequent cause of hospitalization and mortality in Western countries. Sepsis exposes the patient to multiple complications, including thrombotic complications, due to the ability of circulating bacteria to activate platelets. One of the bacteria most frequently implicated in sepsis, Escherichia coli, a Gram-negative bacillus, has been described as being capable of inducing platelet activation during sepsis. However, to date, the mechanisms involved in this activation have not been clearly established, due to their multiple characteristics. Many signaling pathways are thought to be involved. At the same time, reports on the use of antiplatelet agents in sepsis to reduce platelet activation have been published, with variable results. To date, their use in sepsis remains controversial. The aim of this review is to summarize the currently available knowledge on the mechanisms of platelet activation secondary to Escherichia coli sepsis, as well as to provide an update on the effects of antiplatelet agents in these pathological circumstances

Activation peptide of the coagulation factor XIII (AP-F13A1) as a new biomarker for the screening of colorectal cancer

International audienceBackground: Colorectal cancer (CRC) remains a major cause of cancer fatalities in developed countries. The risk of death is correlated to the stage of CRC during the primary diagnosis. Early diagnosis is closely associated with enhanced survival rate. We therefore investigated the AP-F13A1 as a potential protein marker of CRC. Methods: The protein expression of FXIII in 40 serum samples was evaluated by enzyme-linked immunosorbent assays. Additionally, targeted proteomic assays (LC-PRM) were used to evaluate the expression of the activation peptide of F13A1 (AP-F13A1) in a further 113 serum samples. Results were analyzed by the Wilcoxon test and receiver operating characteristic curves generated to assess statistical differences and diagnostic factors between CRC patients and controls. Results: AP-F13A1 was quantified in human serum samples using calibration curves with excellent linearity. AP-F13A1 was reduced in CRC patients using PRM assays from two distinct biobanks. The AUC for AP-F13A1 were 0.95 and 0.93. Sensitivity/specificity values for the two sets of patients were 75%/95% and 71%/95% respectively. Conclusion: We have presented the proof of principle that in vivo release of AP-F13A1 can be measured by PRM-based strategies in CRC serum samples. AP-F13A1 may be an effective serological biomarker as part of a screening program of CRC detection

Long-term production of greenhouse gases from exposed continental shelves and oceanic islands during Quaternary glacial periods

The EPICA Dome C ice core in Antarctica has yielded an 800,000-year record of atmospheric carbon dioxide and methane composition from the Middle Pleistocene climatic transition to the present. In this record, there is a sharp increase in both carbon dioxide and methane immediately following the glacial maxima during the glacial periods which to date remains difficult to explain. We will present evidence to show that the exposed continental shelves and ...published_or_final_versio

Las aves marinas

THIBON A., TARDIEU C., CAMOIN A. 2017