The fate of biogenic iron during a phytoplankton bloom induced by natural fertilisation: Impact of copepod grazing

International audienceThe impact of copepod grazing on Fe regeneration was investigated in a naturally iron fertilised area during KEOPS (Kerguelen Ocean and Plateau compared Study, Jan.-Feb. 2005). 55Fe labelled natural plankton assemblages (< 200 μm) were offered as food to copepod predators sampled in the field (Calanus propinquus, Rhincalanus gigas, Metridia lucens and Oithona frigida). Diatoms (Eucampia antarctica, Corethron inerme and Navicula spp.) constituted the bulk of the protists whereas microzooplankton (i.e. ciliates and dinoflagellates) were in very low abundance. Copepod grazing on phytoplankton ranged from 0.3 to 2.6 µgC ind-1 d-1 and reflected low utilisation of the food stocks (1-10% of total Chlorophyll a d-1) and low daily rations (0.2-3.3 % body C d-1). Copepod grazing resulted in a 1.7-2.3-fold increase in Fe regeneration. Fe speciation determined by extraction onto C18 columns showed that less than 1% of the regenerated Fe was complexed with hydrophobic organic ligands. This suggests that Fe was regenerated as inorganic species and/or bound to freely soluble organic ligands. The biogenic Fe budget established from our study and literature based data indicates that most of the primary production is recycled through the detrital pool, which represents the largest Fe pool (49% of total Fe). Our iron budget further indicates that mesozooplankton and diatoms represent the dominant Fe biomasses above the Kerguelen plateau. The rate of Fe regeneration accounts for half of the Fe demand, strengthening the need for new Fe sources to sustain the massive phytoplankton bloom above the Kerguelen plateau

Ets-1 interacts through a similar binding interface with Ku70 and Poly (ADP-Ribose) Polymerase-1

International audienc

Adaptation méthodologique de l’indicateur PH2 - Phytoplancton en Méditerranée - 1ère partie. Synthèse des spécificités de la Méditerranée : paramètres abiotiques et biomasse phytoplanctonique totale (chl a).

L’évaluation DCSMM de l’état écologique des Habitats pélagiques repose sur le seul critère D1C6 dans les 4 sous-régions marines françaises (Manche - Mer du Nord, Mers Celtiques, Golfe de Gascogne et Méditerranée Occidentale). Les 3 indicateurs utilisés (PH1, PH2 et PH3) ont été développés par OSPAR pour l’Atlantique Nord-Est. Ils ciblent les caractéristiques des communautés phyto- et zooplanctoniques dont l’organisation est contrôlée par les facteurs abiotiques et biotiques propres à chaque sous-région marine. Les fortes spécificités du milieu pélagique méditerranéen n’ont pas été prises en compte lors de l’évaluation 2018. Cette note synthétise les principales caractéristiques abiotiques de la Méditerranée et leurs impacts sur le développement de la biomasse phytoplanctonique totale (chl a). Il est rappelé en particulier que : • La Méditerranée est un bassin d’évaporation, où les apports d’eau douce ne compensent pas les pertes dues à l’évaporation. Le déficit en eau (≈ 1 m par an) est comblé par une entrée d’Eau Atlantique qui pénètre en surface en Méditerranée par le détroit de Gibraltar. Le flux entrant d’Eau Atlantique, le stress lié aux vents et la bathymétrie contrôlent la circulation de surface de toute la Méditerranée. • Les forçages hydrodynamiques contraignent les distributions horizontale et verticale de la biomasse phytoplanctonique. La distribution horizontale du phytoplancton est caractérisée par une hétérogénéité spatiale importante. • L’oligotrophie de la Méditerranée augmente d’Ouest en Est. En Méditerranée Occidentale, elle est modulée par une série de processus physiques (gyres, systèmes frontaux, ondes internes, …) qui agissent à différentes échelles spatiales et temporelles et enrichissent la couche de surface en nutriments. • Dans la ZEE française, et à l’exception de la région du delta du Rhône, les eaux du large sont plus riches en nutriments et en phytoplancton que les eaux côtières. • Du printemps à la fin de l’automne, une thermocline saisonnière isole les eaux chaudes de surface des eaux froides présentes en profondeur. Durant cette période, les eaux situées au-dessus de la thermocline sont épuisées en nutriments et en phytoplancton dans toutes les zones du large. • Une caractéristique majeure du phytoplancton méditerranéen est la présence d’un maximum profond de chlorophylle (« Deep Chlorophyll Maximum », DCM) pendant toute la période stratifiée. Le DCM est observé dans toute la Méditerranée. Il est situé sous la thermocline et n’est pas détecté par les satellites. Le DCM est une entité dynamique dont les caractéristiques sont contrôlées par les variables abiotiques du milieu. Il constitue la source de nourriture principale pour le zooplancton 6 à 8 mois par an, et attire une partie de l’ichtyoplancton qui s’y rassemble pour profiter de l’agrégation de nourriture. Le DCM a donc un rôle essentiel dans le fonctionnement du milieu pélagique méditerranéen. Les éléments présentés dans ce travail montrent la nécessité : (i) d’intégrer la dimension verticale de la colonne d’eau dans l’évaluation DCSMM de l’état écologique des Habitats pélagiques méditerranéens, (ii) d’adapter l’indicateur PH2-Phytoplancton en intégrant la dimension verticale afin de tendre vers une évaluation réaliste de l’état des Habitats pélagiques méditerranéens

Temporal trends and risks factors for antimicrobial resistant Enterobacteriaceae urinary isolates from outpatients in Guadeloupe.

International audienceUrinary tract infections are bacterial infections most commonly encountered in the community. The resistance rate of uropathogens to commonly prescribed antibiotics has increased worldwide but there are no published data concerning the resistance of strains isolated from community-acquired UTI in Guadeloupe. To assess the susceptibility patterns of Enterobacteriaceae strains isolated from outpatients in Guadeloupe we conducted a prospective study from December 2012 to May 2014 among outpatients consulting at private and public laboratories for urine analysis. Risk factors for E. coli resistance to amoxicillin, third-generation cephalosporin, and ciprofloxacin were also determined. To study the trends of E. coli resistance rates over the past 10 years, data on the susceptibility patterns of E. coli from 2003 to 2014 were also collected from three major laboratories for a retrospective study. During the prospective study, we isolated 1293 bacterial strains from the urine of outpatients presenting for urine analysis. The most commonly isolated bacteria were E. coli (57 %) and Klebsiella pneumoniae (15.5 %). Thirty seven per cent of the E. coli strains were resistant to amoxicillin. Resistance rates to third generation cephalosporin were low for E. coli and other Enterobacteriaceae (3.1 and 12.2 % respectively) and mostly due to the presence of an Extended Spectrum Beta-lactamase. Resistance to cotrimoxazole and ciprofloxacin was moderate (17.8 and 15.6 % respectively). However, the resistance rate of E. coli to ciprofloxacin has significantly increased during the last 10 years. Risk factors were consistent with previously reported data, especially for the increasing ciprofloxacin resistance with age. General practitioners in Guadeloupe need to be better informed to favor the prescription of fosfomycin-trometamol to reduce the risk of resistance to fluoroquinolones

Analysis of the proximal promoter of the human colon-specific B4GALNT2 (Sda synthase) gene: B4GALNT2 is transcriptionally regulated by ETS1

13siopenBackground: The Sda antigen and corresponding biosynthetic enzyme B4GALNT2 are primarily expressed in normal colonic mucosa and are down-regulated to a variable degree in colon cancer tissues. Although their expression profile is well studied, little is known about the underlying regulatory mechanisms. Methods: To clarify the molecular basis of Sda expression in the human gastrointestinal tract, we investigated the transcriptional regulation of the human B4GALNT2 gene. The proximal promoter region was delineated using luciferase assays and essential trans-acting factors were identified through transient overexpression and silencing of several transcription factors. Results: A short cis-regulatory region restricted to the −72 to +12 area upstream of the B4GALNT2 short-type transcript variant contained the essential promoter activity that drives the expression of the human B4GALNT2 regardless of the cell type. We further showed that B4GALNT2 transcriptional activation mostly requires ETS1 and to a lesser extent SP1. Conclusions: Results presented herein are expected to provide clues to better understand B4GALNT2 regulatory mechanisms.openWavelet-Vermuse C.; Groux-Degroote S.; Vicogne D.; Cogez V.; Venturi G.; Trinchera M.; Brysbaert G.; Krzewinski-Recchi M.-A.; Bachir E.H.; Schulz C.; Vincent A.; Van Seuningen I.; Harduin-Lepers A.Wavelet-Vermuse, C.; Groux-Degroote, S.; Vicogne, D.; Cogez, V.; Venturi, G.; Trinchera, M.; Brysbaert, G.; Krzewinski-Recchi, M. -A.; Bachir, E. H.; Schulz, C.; Vincent, A.; Van Seuningen, I.; Harduin-Lepers, A

Changes in ecosystems, climate and societies in the Jura Mountains between 40 and 8 ka cal BP

International audienceWe present radiometric, palaeoclimatological, palaeoenvironmental and archaeological data for the period 40 000–8000 cal BP in the Jura Mountains (eastern France). These mountains culminate at ∼1700 m a.s.l. and are today characterised by a semi-continental climate. During the Last Glacial Maximum, the range supported a local ice cap. While recent data suggest a possible early ice-cap development during MIS 4, the chronology of the regional LGM and following deglaciation has still to be refined. The complete disappearance of the local ice cap at ca 17 000–16 600 cal BP marked the beginning of accumulation of sediment archives in the Jurassian lakes and mires, which favoured the reconstruction of past changes in climatic and environmental conditions, in addition to faunal remains found in caves and in archaeological sites. Three main successive stages may be distinguished regarding the history of societies. The first stage at ca 40 000–18 700 cal BP was characterized by very few archaeological sites with only discontinuous intermittent occupations, always located outside the Jura range. The second stage, around 18 700–11 700 cal BP, corresponded to an increase in the population density, as suggested by an increasing number of archaeological sites and a progressive colonisation of elevated areas of the Jura Mountains. The third stage at ca 11 700–8000 cal BP coincided with a reinforcement of settlement in the lowland areas as well as a development of long-term occupations in elevated areas. The millennial-scale GS-1 cold event had a more long-lasting and stronger impact on societies than did the 200 year-long 8.2 ka cold event

KCNQ2 R144 variants cause neurodevelopmental disability with language impairment and autistic features without neonatal seizures through a gain-of-function mechanism

Prior studies have revealed remarkable phenotypic heterogeneity in KCNQ2-related disorders, correlated with effects on biophysical features of heterologously expressed channels. Here, we assessed phenotypes and functional properties associated with KCNQ2 missense variants R144W, R144Q, and R144G. We also explored in vitro blockade of channels carrying R144Q mutant subunits by amitriptyline

Antifungal Susceptibility Profiles of 1698 Yeast Reference Strains Revealing Potential Emerging Human Pathogens

New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites) were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes). Interestingly, geometric mean minimum inhibitory concentrations (MICs) of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001). Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically “resistant” to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens

Malaria infection and disease in an area with pyrethroid-resistant vectors in southern Benin

<p>Abstract</p> <p>Background</p> <p>This study aimed to investigate baseline data on malaria before the evaluation of new vector control strategies in an area of pyrethroid-resistance of vectors. The burden of malaria was estimated in terms of infection (prevalence and parasite density) and of clinical episodes.</p> <p>Methods</p> <p>Between December 2007 and December 2008 in the health district of Ouidah - Kpomassè - Tori Bossito (southern Benin), a descriptive epidemiological survey of malaria was conducted. From 28 selected villages, seven were randomized from which a total of 440 children aged 0 to 5 years were randomly selected. Clinical and parasitological information was obtained by active case detection of malaria episodes carried out during eight periods of six consecutive days scheduled at six weekly intervals and by cross-sectional surveys of asymptomatic infection. Entomological information was also collected. The ownership, the use and the correct use of long-lasting insecticide-treated nets (LLINs) were checked over weekly-survey by unannounced visits at home in the late evening.</p> <p>Results</p> <p>Mean parasite density in asymptomatic children was 586 <it>P. falciparum </it>asexual forms per μL of blood (95%CI 504-680). Pyrogenic parasite cut-off was estimated 2,000 <it>P. falciparum </it>asexual blood forms per μL. The clinical incidence of malaria was 1.5 episodes per child per year (95%CI 1.2-1.9). Parasitological and clinical variables did not vary with season. <it>Anopheles gambiae </it><it>s.l</it>. was the principal vector closely followed by <it>Anopheles funestus</it>. Entomological inoculation rate was 5.3 (95%CI 1.1-25.9) infective bites per human per year. Frequency of the L1014F <it>kdr </it>(West) allele was around 50%. Annual prevalence rate of <it>Plasmodium falciparum </it>asymptomatic infection was 21.8% (95%CI 19.1-24.4) and increased according to age. Mean rates of ownership and use of LLINs were 92% and 70% respectively. The only correct use of LLINs (63%) conferred 26% individual protection against only infection (OR = 0.74 (95%IC 0.62-0.87), p = 0.005).</p> <p>Conclusion</p> <p>The health district of Ouidah-Kpomassè-Tori Bossito is a mesoendemic area with a moderate level of pyrethroid-resistance of vectors. The used LLINs rate was high and only the correct use of LLINs was found to reduce malaria infection without influencing malaria morbidity.</p

A global perspective on the trophic geography of sharks

Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.This research was conducted as part of C.S.B.’s Ph.D dissertation, which was funded by the University of Southampton and NERC (NE/L50161X/1), and through a NERC Grant-in-Kind from the Life Sciences Mass Spectrometry Facility (LSMSF; EK267-03/16). We thank A. Bates, D. Sims, F. Neat, R. McGill and J. Newton for their analytical contributions and comments on the manuscripts.Peer reviewe