Echinometra mathaei and its ectocommensal shrimps: the role of sea urchin spinochrome pigments in the symbiotic association

peer reviewe

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Les anamorphoses du réel dans l'oeuvre littéraire et cinématographique de Woody Allen (l'Amor / la mort du réel)

La renommée de Woody Allen repose essentiellement sur ses qualités d'acteur "comique" et de réalisateur de comédies, qu il s'agisse de "pures" comédies ou de "comédies dramatiques". Il est désormais avéré que son œuvre s'inspire largement à la fois du cinéma américain et européen. Toutefois son œuvre comporte également des écrits, qui partagent certaines des caractéristiques des films pour lesquels il est connu. L'une d'elles est le lien entre réalité et imaginaire, en particulier la place offerte par l'homme substituts artistiques pour supporter et comprendre la réalité, à commencer par la sienne propre en tant qu'homme et artiste potentiel. Ce travail entend ainsi rendre hommage à l'ensemble de l'œuvre de Woody Allen, ceci selon un angle qui devrait mettre en lumière l'intertextualité littéraire et artistique très riche de l'œuvre d'Allen ainsi que la profondeur de sa pensée sur le sujet.Woody Allen is best known as a comedian and film-maker, prone to make and appear in comedies, both "mere" comedies or dramatic comedies. It has become a well-known fact that his work has been much inspired by both American and European cinemas. However his work also implies writing pieces, which share some characteristics with the films he is famous for. One of them is the link between reality and fantasy, more specifically the place man gives to artistic substitutes to undergo and understand reality, starting with his own being as a man and as a potential artist. Thus this work means to pay tribute to the whole work of Woody Allen under a scope which should highlight the very rich literary and artistic intertextuality of Allen's work as well as the depth of his insights on the subject.POITIERS-BU Droit Lettres (861942101) / SudocSudocFranceF

Characteristics of the infestation of Seriatopora corals by the coral gall crab Hapalocarcinus marsupialis Stimpson, 1859 on the great reef of toliara, Madagascar

peer reviewedThis study describes the association between the obligatory symbiont coral gall crab Hapalocarcinus marsupialis and its stony coral hosts Seriatopora sp .within the Great Reef of Toliara in Madagascar and attempts to dis- cuss their symbiotic status through comparison with previous studies. These corals are inhabited by crabs living in galls that can be categorised in four distinct morphological stages, where the first one corresponds to a small bud and the last one represents a completely closed gall surrounding the crab inside. Within the reef, 563 colonies of Seriatopora species were observed by scuba-diving at ten different stations: 37.8 % of them were infested by H. marsupialis , with a total of 763 galls, and with a majority of stage 4 galls. Galls are monopolised by females that can have different morphologies. Females store the sperm in two spermathecae and are fertilised when their morphology and size are similar to males and the gall is not closed. Histological observations coupled with scanning electronic microscopy analyses show that closed galls are made of an external living tissue, a mid skeletal layer and an internal living tissue. The internal living tissue includes polyps similar to the external tissue, some of them being sex- ually mature. Nitrogen and carbon isotopic signatures confirmed that these crabs are filter-feeders and do not feed on their host. This association perfectly highlights the difficul- ties to define the symbiotic status of a symbiont if one con- siders inflexible the three categories of symbiosis commonly defined.DÉVELOPPEMENT DE POLYAQUACULTURES DANS LES VILLAGES CÔTIERS DU SUD-OUEST ET DU NORD DE MADAGASCA

Echinometra mathaei and its ectocommensal shrimps: the role of sea urchin spinochrome pigments in the symbiotic association

Tuleariocaris holthuisi and Arete indicus are two ectocommensal shrimps closely associated with the tropical sea urchin Echinometra mathaei. This study provides a comparison of these two E. mathaei symbiotic crustaceans and particularly focuses on the relationship between T. holthuisi and its host’s pigments (i.e. spinochromes), and its dependency on its host. While all the analyses underline a close association between A. indicus and E. mathaei, they reveal a particularly close interaction between T. holthuisi and its host. Chemical analyses reveal that these shrimps present the same spinochrome composition as E. mathaei, and have similar colouration, allowing camouflage. Isotopic composition and pigment loss after host separation suggest that these pigments are certainly assimilated upon feeding on the urchin. Moreover, symbiont isolation experiments demonstrate the high dependency of T. holthuisi on its host and the importance of the host’s pigments on their survival capacity. Finally, some host recognition mechanisms are investigated for T. holthuisi and show the probable implication of spinochromes in host selection, through chemical recognition. Hence, all the results suggest the essential roles of spinochromes for T. holthuisi, which, in turn, suggests the potential implication of these pigments in the shrimps’ metabolism

Characterization of a population of the Harlequin crab, Lissocarcinus orbicularis Dana, 1852, an obligate symbiont of holothuroids, in Toliara bay (Madagascar)

Harlequin crabs, Lissocarcinus orbicularis, are commensals found on the integument and in the buccal/cloacal cavity of several species of holothuroids. The population of these crabs was investigated on holothuroids of the barrier reef of Toliara (South-West of Madagascar) from 2002 to 2008. Seventeen holothuroid species were observed and eight were crab hosts. There is generally one adult crab or a heterosexual pair per infested holothuroid but up to ten juveniles were recorded on a Thelenota ananas. Carapace length of the observed L. orbicularis was from 0.3 to 1.4 cm from the tip of the rostrum to the end of the cephalothorax, with a mean length of 0.85 cm. L. orbicularis is characterized by a weak sexual dimorphism (females are bigger than males) and the presence of pereiopods morphologically adapted to fixation on the host integument. Gravid females were observed at each month of the survey indicating that the crab reproduces all the year. Considering our results and personal observations, we also discuss the monogamy mating system of the Harlequin crab

Backward Compatible Update of the Timing System of WEST

International audienceBetween 2013 and 2016, the tokamak Tore Supra in operation at Cadarache (CEA-France) since 1988 underwent a major upgrade following which it was renamed WEST (Tungsten [W] Environment in Steady state Tokamak). The synchronization system however was not upgraded since 1999*. At the time, a robust design was achieved based on AMD’s TAXI chip**: clock and events are distributed from a central emitter over a star shaped network of simplex optical links to electronic crates around the tokamak. Unfortunately, spare boards were not produced in sufficient quantities and the TAXI is obsolete. In fact, multigigabit serial communication standards question the future availability of any such low rate SerDeses. Designing replacement boards provides an opportunity for a new CDR solution and extended functionalities (loss-of-lock detection, latency monitoring). Backward compatibility is a major constraint given the lack of resources for a full upgrade. We will first describe the current state of the timing network of WEST, then the implementation of a custom CDR in full firmware, using the IOSerDeses of Xilinx FPGAs and will finally provide preliminary results on development boards

The diet of the Harlequin crab Lissocarcinus orbicularis, an obligate symbiont of sea cucumbers (holothuroids) belonging to the genera Thelenota, Bohadschia and Holothuria

peer reviewedThe present paper characterizes, for the first time, the diet of the Harlequin crab, Lissocarcinus orbicularis an obligate symbiotic crab that associates with sea cucumbers (holothuroids) belonging to the genera Thelenota, Bohadschia and Holothuria. These tropical holothuroids host a rich symbiotic community in the Indo-West Pacific Ocean of which the Harlequin crab is the best known. The diet of L. orbicularis was characterized by analyzing the microscopic, molecular and isotopic signatures obtained from its gastric content. The presence of sea cucumber ossicles in the gastric mills of the crabs suggests that symbionts eat the superficial integument of their host and this was suppoarted by the fact that Holothuroid DNA was detected in the stomach of L.orbicularis after DGGE and sequencing of the 18S rDNA gene. The stable isotopic δ13C and δ15N values of crab tissues were compared with diverse potential food sources including the three holothuroids, three algae, one sea grass as well as the organic matter contained in the water column, in the sediment, and the second most abundant symbiont, the polychaete Gastrolepidia clavigera. The low δ15N values of crabs suggest that the crabs do not exclusively feed on sea cucumber tissue but assimilate diverse food sources such as sea grasses and organic matter contained in sediment that have similar δ13C values. There were no difference between the feeding of males and females but there was a positive correlation between the carapace length and the stable isotopic values indicating a shift of the food source as crabs grow larger.Echinoderm Symbiosi