Éditeur(s) : HAL CCSD
Résumé : International audience
Studies report that foetal exposure to paracetamol by maternal consumption can interfere with male reproductive development. Moreover, recent biomonitoring data report widespread presence of paracetamol in German and Danish populations, suggesting exposure via secondary (non-pharmaceutical) sources such as metabolic conversion from the ubiquitous industrial compound aniline. In this study we investigated the extent to which paracetamol and aniline can interfere with female reproductive development. Intrauterine exposure to paracetamol by gavage of pregnant dams resulted in shortening of the anogenital distance in adult offspring, suggesting that foetal hormone signalling had been disturbed. Female offspring of paracetamol-exposed mothers had ovaries with diminished follicle reserve and reduced fertility. Foetal gonads of exposed animals had also reduced gonocyte numbers, suggesting that the reduced follicle count in adults could be due to early disruption of germ cell development. However, ex vivo cultures of ovaries from 12.5 days post coitum foetuses showed no decrease in proliferation or expression following exposure to paracetamol. This suggests that the effect of paracetamol occurs prior to this developmental stage. Accordingly, using embryonic stem cells as a proxy for primordial germ cells we show that paracetamol is an inhibitor of cellular proliferation, but without cytotoxic effects. Collectively, our data show that intrauterine exposure to paracetamol at levels commonly observed in pregnant women, as well as its precursor aniline, may block primordial germ cell proliferation, ultimately leading to reduced follicle reserves and compromised reproductive capacity later in life
Toxicological Sciences

hal-01259211
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01259211
DOI : 10.1093/toxsci/kfv332
PUBMED : 26732887

Éditeur(s) : HAL CCSD Springer Verlag (Germany) Springer Verlag
Résumé : International audience
Separated olivine grains from a deeply subducted serpentinized wehrlite (Changawuzi in the western Tianshan ultrahigh-pressure belt, China) were analysed with unpolarized transmission FTIR and the Ti contents were determined using LA-ICP-MS. The major bands in the olivine spectra display striking similarities to Ti-clinohumite and are interpreted as OH in lamellae. The quantification of the water content in lamellae requires calibration of the IR-absorption for such bands. We have obtained a new absorption coefficient for Ti-clinohumite of 0.125+/−0.017 ppm cm2 based on polarized FTIR measurements on three orthogonal sections through a large single crystal of Ti-clinohumite from Val Malenco, which has a known water content of 1.53 wt%. The resulting water content in olivine using this calibration factor ranges from 440 to 2,600 ppm and correlates positively with the Ti content that ranges from 130 to 1,400 ppm. For the quantification of the water content in Ti-chondrodite and Ti-clinohumite that are associated with olivine, we developed a new method using attenuated total reflectance FTIR spectroscopy. Ti-chondrodite and Ti-clinohumite display similar IR bands at ~3,562, 3,525 and ~3,583–3,586 cm−1. As in olivine, the water content and Ti content correlate in both Ti-clinohumite and Ti-chondrodite, indicating an intergrowth of these minerals, which has been confirmed by TEM analyses. Our results confirm previous suggestions that there is a strong correlation between the Ti content of ultramafic rocks and their capacity to transport water to the deeper mantle in subduction zones beyond conditions where hydrous phases are stable.
ISSN: 0010-7999

hal-01172237
https://hal.archives-ouvertes.fr/hal-01172237
DOI : 10.1007/s00410-014-0992-8

Éditeur(s) : HAL CCSD Society for Range Management
Résumé : Grasslands and agroecosystems occupy one-third of the terrestrial area, but their contribution to the global carbon cycle remains uncertain. We used a set of 316 site-years of CO(2) exchange measurements to quantify gross primary productivity, respiration, and light-response parameters of grasslands, shrublands/savanna, wetlands, and cropland ecosystems worldwide. We analyzed data from 72 global flux-tower sites partitioned into gross photosynthesis and ecosystem respiration with the use of the light-response method (Gilmanov, T. G., D. A. Johnson, and N. Z. Saliendra. 2003. Growing season CO(2) fluxes in a sagebrushsteppe ecosystem in Idaho: Bowen ratio/energy balance measurements and modeling. Basic and Applied Ecology 4:167-183) from the RANGEFLUX and WORLDGRASSAGRIFLUX data sets supplemented by 46 sites from the FLUXNET La Thuile data set partitioned with the use of the temperature-response method (Reichstein, M., E. Falge, D. Baldocchi, D. Papale, R. Valentini, M. Aubinet, P. Berbigier, C. Bernhofer, N. Buchmann, M. Falk, T. Gilmanov, A. Granier, T. Grunwald, K. Havrankova, D. Janous, A. Knohl, T. Laurela, A. Lohila, D. Loustau, G. Matteucci, T. Meyers, F. Miglietta, J.M. Ourcival, D. Perrin, J. Pumpanen, S. Rambal, E. Rotenberg, M. Sanz, J. Tenhunen, G. Seufert, F. Vaccari, T. Vesala, and D. Yakir. 2005. On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm. Global Change Biology 11: 1.424-1439). Maximum values of the quantum yield (alpha = 75 mmol.mol(-1)), photosynthetic capacity (A(max) = 3.4 mg CO(2) . m(-2).s-1), gross photosynthesis (P(g,max) = 1.16 g CO(2) . m(-2).d(-1)), and ecological light-use efficiency (epsilon(ecol) = 59 mmol . mol(-1)) of managed grasslands and high-production croplands exceeded those of most forest ecosystems, indicating the potential of nonforest ecosystems for uptake of atmospheric CO(2). Maximum values of gross primary production (8 600 g CO(2) . m(-2).yr(-1)), total ecosystem respiration (7 900 g CO(2) . m(-2).yr(-1)), and net CO(2) exchange (2 400 g CO(2) . m(-2).yr(-1)) were observed for intensively managed grasslands and high-yield crops, and are comparable to or higher than those for forest ecosystems, excluding some tropical forests. On average, 80% of the nonforest sites were apparent sinks for atmospheric CO(2), with mean net uptake of 700 g CO(2) . m(-2).yr(-1) for intensive grasslands and 933 g CO(2) . m(-2).d(-1) for croplands. However, part of these apparent sinks is accumulated in crops and forage, which are carbon pools that are harvested, transported, and decomposed off site. Therefore, although agricultural fields may be predominantly sinks for atmospheric CO(2), this does not imply that they are necessarily increasing their carbon stock.
ISSN: 1550-7424

hal-01190754
https://hal.archives-ouvertes.fr/hal-01190754
DOI : 10.2111/rem-d-09-00072.1
PRODINRA : 214043

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Comme dans d’autres régions du monde, la croissance démographique et l’aménagement côtier sur le littoral acadien au Nouveau-Brunswick contribuent à une plus grande vulnérabilité et à la détérioration des espaces côtiers et environnements littoraux. L’élévation du niveau marin et les effets des changements climatiques rendent les côtes du Nouveau-Brunswick extrêmement sensibles et entrainent des impacts de plus en plus importants. Ainsi, l’adaptation aux changements climatiques constitue un enjeu de taille pour la province.Nous décrivons ici les résultats d’une étude comparative sur les expériences et les stratégies d’adaptation de deux communautés côtières, les communautés de Cocagne - Grande Digue et de Beaubassin-Est - Cap Pelé. Les deux territoires ont en commun d’avoir des littoraux convoités par le tourisme et le secteur immobilier. Des entretiens semi-dirigés et des groupes de discussion (focus groups) ont permis d’obtenir des informations sur les thématiques suivantes : l’expérience des modifications environnementales, les mesures d’adaptation initiées individuellement ou collectivement, les réactions et les besoins futurs. Les résultats de l’étude mettent en évidence l’enchâssement des aspects économiques et sociétaux dans les enjeux environnementaux et le rôle des représentations et des acteurs qui déterminent le niveau de mobilisation. Enfin, le projet souligne l’importance d’une coordination entre les différentes échelles de gouvernance.
As in other parts of the world, population growth and coastal planning on New Brunswick’s Acadian coastline are contributing to greater vulnerability and deterioration of the natural environment. The rise in sea level and the effects of climate change make the coasts of New Brunswick extremely sensitive, leading to impacts that are increasingly larger. Thus, adaptation to climate change is a major challenge for the province.Here, we describe the results of a comparative study of the experiences and coping strategies of two coastal communities: Cocagne – Grande-Digue and Beaubassin East – Cap-Pelé. Both these territories attract tourism and real estate investors. Semi-structured interviews and focus groups were used to obtain information on the following topics: the experience of environmental change, adaptation measures initiated individually or collectively, reactions and future needs. Results of the study highlight the entrenchment of economic and societal aspects of environmental issues and the role of representations and stakeholders that determine the level of mobilization. Finally, the project emphasizes the importance of coordination between the different levels of governance.
Acadie
Nouveau-Brunswick

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.6663
http://journals.openedition.org/etudescaribeennes/6663

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Seven male subjects volunteered to participate in an investigation of whether the diurnalincrease in core temperature influences the effects of pre-cooling or passivewarm-up on muscular power. Morning (07:00-09:00 h) and afternoon (17:00-19:00 h) evaluation of maximal power output during a cycling sprint was performed on different days in a control condition (room at 21.8 °C, 69% rh), after 30 min of pre-cooling in a cold bath (16 °C), or after 30 min of passivewarm-up in a hot bath (38 °C). Despite an equivalent increase from morning to afternoon in core temperature in all conditions (+0.4 °C, P < 0.05), power output displayed a diurnalincrease in control condition only. A local cooling or heating of the leg in a neutral environment blunted the diurnal variation in muscular power. Because pre-cooling decreases muscle power, force and velocity irrespective of time-of-day, athletes should strictly avoid any cooling before a sprint exercise. In summary, diurnal variation in muscle power output seems to be more influenced by muscle rather than core temperature.
ISSN: 1440-2440

hal-00706159
https://hal.univ-antilles.fr/hal-00706159
DOI : 10.1016/j.jsams.2007.09.008

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Tout en étant une des régions les plus pauvres du Pérou, le sud andin est la destination touristique nationale par excellence où se trouve le sanctuaire archéologique de Machu Picchu, un des sites du patrimoine mondial les plus prisés au monde. Le boom du développement touristique des années 1990 à rapidement transformé la région de Cuzco en une destination écotouristique et de tourisme culturel. Cette étude présente le développement du tourisme dans la région en général, ainsi que les effets sur quelques communautés spécifiques s’étant intégrées au système touristique international grâce au développement du chemin de l’inca, une randonnée de quatre jours servant de porte d’entrée à Machu Picchu. Les hommes des communautés paysannes des hauts plateaux andins avoisinant Ollantaytambo ont été sollicités pour transporter l’équipement nécessaire au service des randonneurs étrangers. Ces habitants représentaient une main d’œuvre accessible, abordable, voire exploitable, capable physiquement de transporter des poids lourds en haute altitude. Aujourd’hui, la Fédération des Porteurs Daniel Estrada est composée de 6200 porteurs provenant de différentes communautés de la vallée. Essentiellement quechuas, ces communautés rurales marginalisés survivent sur des terres arides ; leur niveau d’éducation ne dépasse souvent pas le primaire ; les villages ne disposent pas d’eau potable, de services d’égouts, d’électricité, de téléphone, d’accès à des services de santé ; les habitations sont faites d’adobe. Étant donné la vulnérabilité de ces populations, l’intégration à un système offrant de nouvelles possibilités de revenus s’avérait souhaitable, malgré les conditions d’emploi déplorables.
While one of the poorest regions of Peru, the Andean south is a national tourist destination and the site of the archaeological sanctuary and one of the most popular sites in the world, Machu Picchu. The boom of tourism development in the 1990s quickly transformed the Cuzco region to an ecotourism and cultural tourism destination. This paper presents the development of tourism in the region in general, as well as the effects for some communities as they are integrated into the international tourism system through the development of the Inca Trail, a four-day hike which leads to Machu Picchu. Men in the peasant communities in the Andean highlands surrounding Ollantaytambo are asked to carry the equipment needed by foreign hikers during the ascent. These people represent an available and affordable workforce, physically capable of carrying heavy weight at high altitudes. Today, the Daniel Estrada Federation of Carriers is composed of 6200 carriers from different communities in the valley. Mainly Quechua, these marginalized rural populations survive in an arid environment; their education often does not exceed the primary level; the villages lack drinking water, sewage services, electricity, telephones, and access to health services; and the houses are made of adobe. Given the vulnerability of these populations, the integration of a system offering new revenue opportunities proved desirable, in spite of the deplorable employment conditions.
Pérou

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.6550
http://journals.openedition.org/etudescaribeennes/6550

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Cet article présente une évaluation des bénéfices de la protection par le Conservatoire du littoral et ses partenaires des mangroves de Guyane, Guadeloupe, Martinique, Mayotte et Saint-Martin. Il détaille l’évaluation des services écosystémiques des mangroves sur ces territoires, puis développe des projections pour l’évolution de leurs surfaces en présence ou en absence de protection par le Conservatoire du littoral et ses partenaires. Évaluation et projections ont permis d’estimer les conséquences économiques de cette protection sur 25 ans. Les bénéfices calculés de cette protection sont compris entre 33 000 €/ha et 51 000 €/ha pour les mangroves soumises à des pressions anthropiques importantes. Le maintien des services de régulation correspond à 90 % de cette valeur, surtout pour la capacité des mangroves à épurer les eaux continentales, à protéger et stabiliser la côte et à participer à la régulation du climat global en séquestrant du carbone. Ces résultats objectivent la place des mangroves dans l’économie locale du littoral outre-mer et offrent un plaidoyer pour l’acquisition et la protection des espaces les plus vulnérables par le Conservatoire du littoral et ses partenaires. Les limites inhérentes aux méthodologies utilisées s’appliquent ici : ces évaluations permettent de capter les valeurs d’usage des écosystèmes, mais ne prennent pas en compte la totalité des valeurs de biodiversité, telles que les valeurs de non-usage ou les aspects liés aux espèces remarquables des mangroves. Toutefois, les résultats de ce travail permettent de donner des estimations réalistes à considérer comme des bornes inférieures de la valeur totale des écosystèmes et de leur protection.
This article presents a valuation of the benefits brought by the protection of mangroves from the Conservatoire du littoral and its partners in French Guiana, Guadeloupe, Martinique, Mayotte and Saint Martin. We detail a contextualized mangroves’ ecosystem services valuation, then develop projections regarding the evolution of their surfaces whether they are protected or not. It was then possible to estimate the economic impacts of 25 years of mangroves protection. When human pressure is high, those benefits range from 33 000 €/ha to 51 000 €/ha. About 90% of this value is due to the conservation of regulating services, such as water treatment capacity, coastal protection and global climate mitigation through carbon sequestration. Our results objectify the importance of mangrove ecosystems in oversea coastal territories’ local economy, and provide advocacy and guidance for the protection strategy of the Conservatoire du littoral and its partners. The methodology we used has inherent limitations one should consider: the ecosystem services valuation focuses on use values and excludes most non-use or intrinsic values, which could also be important for mangroves regarding their remarkable biodiversity. However, our results supply a realistic valuation to be understood as a lower boundary for the total value of oversea mangroves and for the benefits of their protection.
Guadeloupe
Guyane française
Martinique
Mayotte
Saint-Martin

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.10485
http://journals.openedition.org/etudescaribeennes/10485

Éditeur(s) : Elsevier
Résumé : The effect of ambient ammonia, hypoxia and combination of both on survival and the physiological and immunological response of the blue shrimp Litopenaeus stylirostris in relation to molt stage was studied. Shrimp were submitted to 44.0-71.5 mg 1(-1) total ammonia-N corresponding to 2.0 mg 1(-1) unionized ammonia NH3-N and/or to 1.5 mg O-2 1(-1) (4.3 kPa) for 24 hours. Survival was recorded and the molt stages of both dead and surviving shrimp determined. Only shrimp in intermolt and premolt stages were sampled for analysis of haemolymph. Haemolymph was assayed for osmoregulatory capacity (OC), magnesium ion (Mg2+), calcium ion (Ca2+), total proteins, oxyhaemocyanin, lactate, glucose and total haemocyte count (THC). Low mortalities were recorded for shrimp submitted independently to ammonia or hypoxia. Seventy five percent of dead shrimp were in early post molt (stage A) in ammonia treatment, while hypoxia affected mainly late premolt animals (stage D-2). A synergic effect of ammonia and hypoxia combination (A+ O-2 treatment) on mortality was observed, affecting nearly exclusively shrimp in late premolt stage D-2. Analysis of molt stage repartition at the end of the experiment suggests that ammonia treatment may have accelerated molting. The common physiological response of shrimp to the different treatments was characterized by a reduced OC and an increase in Ca2+. Increase in Mg2+ could not be validated by the statistical analysis, as well as glycaemia variations. Plasmatic lactate level increased and THC decreased in shrimp submitted to hypoxia and the combination of hypoxia and ammonia. Total proteins concentration was reduced in ammonia and A+O-2 treatments. The effect was more pronounced in late premolt shrimp than in intermolt shrimp. Combination of ammonia and hypoxia led to a physiological response stronger than this observed for ammonia-alone and/or hypoxia-alone treatments, except for oxyhaemocyanin. The effects of each external factor (ammonia, hypoxia) and the combination of both, and internal one (molt stage) are discussed. (c) 2007 Elsevier B.V All rights reserved.
Aquaculture (0044-8486) (Elsevier), 2008-02 , Vol. 274 , N. 2-4 , P. 398-407

Droits : 2008 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4092.pdf
DOI:10.1016/j.aquaculture.2007.11.033
http://archimer.ifremer.fr/doc/00000/4092/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : A new programme concerning the experimentation of about thirty Fish Aggregating Devices (FADs) is to start in the Cape Verde Islands at the end of 1999. In this context, this communication is intended: - to evaluate the halieutic, economic and social conditions of the artisanal fishery in this archipelago, notably in terms of assets and constraints. Although these conditions are very heterogeneous depending on islands, the fads seem to be able to help the stabilization and the development of the fishing activities, disadvantaged by a low productivity, limited operating ranges of boats, and very irregular outings at sea. But the narrowness of the domestic market is likely to cause drops in the fish prices if the production increases, while the absence of institutional framework may be a handicap at the level of the management (of the programme itself, and/or of some possible conflicts of uses); - to carry out an assessment of the former experiments. It emphasized the insufficiency of the follow-up and the maintenance of the structures, of which the lifespan varied at the most between four and six months, as well as the positive effects of the concentration, and the interest of the fishermen already sensitized with these structures.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15317/12644.pdf
http://archimer.ifremer.fr/doc/00042/15317/

Éditeur(s) : HAL CCSD CSIRO Publishing
Résumé :  
Leaf traits of tropical tree species display an important inter-specific diversity, as detected for instance in the large range of values of leaf mass : area ratio (LMA). They also demonstrate a large irradiance-elicited plasticity, but there is still debate whether this plasticity differs among species. To address this question, leaf traits were recorded on saplings from 12 rainforest tree species in French Guiana, grown under approximately 5, 10 and 20% relative irradiance. Fifteen structural and physiological leaf traits related to photosynthesis were measured. The irradiance-elicited plasticity was quantified using a relative distance plasticity index. A large inter-specific diversity was detected for all leaf traits. A principal component analysis opposed species with a large mass-based photosynthesis, respiration, N content and photosynthetic nitrogen use efficiency, to species with a large leaf mass : area ratio, LMA. The two pioneer species used in this study displayed the largest photosynthetic capacity (and lowest LMA) and ranked at one end of the species continuum. Relative irradiance affected almost all traits with the exception of mass-based photosynthesis.Aweak interaction was found between species and relative irradiance and the species ranking was maintained among relative irradiance treatments for the majority of the traits. A principal component analysis of the values of relative-distance plasticity index failed to reveal any consistent patterns of traits or species.Weconcluded that irradiance-elicited plasticity of leaf traits was similar among species irrespective ofLMA and successional status, despite the occurrence of a large inter-specific diversity for the investigated traits
ISSN: 1445-4408

hal-01032129
https://hal.archives-ouvertes.fr/hal-01032129
DOI : 10.1071/FP09119

Éditeur(s) : Wiley InterScience
Résumé : This paper reports on the status and design of the operational remotely operated vehicle Victor 6000, rated for 6000 m depth and of the 3000 m depth autonomous underwater vehicle Asterxx operated by Ifremer the French Institute for Sea Exploitation. Victor 6000 is part of a global system built of subsystems, scientific modules, winch and cable, dead weight and umbilical, positioning subsystem using acoustic ultra short base line (USBL) techniques, and software for data and dive management. In 2005 the system was equipped with a second toolsled dedicated to high resolution mapping of the sea bed, with both acoustical and optical devices. Asterxx, the first autonomous underwater vehicle (AUV) developed by IFREMER, is 4.5 m in length with a diameter of 0.69 m. Depending on the payload, its weight is between 600 and 800 kg in air,with a diving depth of 3000 m. Its cruising speed is between 0.5 and 2.5 ms. The AUV is capable of carrying various payloads for a wide spectrum of applications. The vehicle can cruise up to 100 km. For coastal applications this vehicle is operable by a limited crew potentially from a nonspecialized vessel. Both vehicles are used for oceanography as well as to continually evolve underwater systems to address new scientific challenges.
Journal of Field Robotics (1556-4959) (Wiley InterScience), 2007-06 , Vol. 24 , N. 6 , P. 449-459

Droits : 2007 Wiley InterScience
http://archimer.ifremer.fr/doc/2007/publication-2806.pdf
DOI:10.1002/rob.20195
http://archimer.ifremer.fr/doc/00000/2806/

Éditeur(s) : Public Library Science
Résumé : Biological invasions rank amongst the most deleterious components of global change inducing alterations from genes to ecosystems. The genetic characteristics of introduced pools of individuals greatly influence the capacity of introduced species to establish and expand. The recently demonstrated heritability of microbial communities associated to individual genotypes of primary producers makes them a potentially essential element of the evolution and adaptability of their hosts. Here, we characterized the bacterial communities associated to native and non-native populations of the marine green macroalga Caulerpa racemosa through pyrosequencing, and explored their potential role on the strikingly invasive trajectory of their host in the Mediterranean. The similarity of endophytic bacterial communities from the native Australian range and several Mediterranean locations confirmed the origin of invasion and revealed distinct communities associated to a second Mediterranean variety of C. racemosa long reported in the Mediterranean. Comparative analysis of these two groups demonstrated the stability of the composition of bacterial communities through the successive steps of introduction and invasion and suggested the vertical transmission of some major bacterial OTUs. Indirect inferences on the taxonomic identity and associated metabolism of bacterial lineages showed a striking consistency with sediment upheaval conditions associated to the expansion of their invasive host and to the decline of native species. These results demonstrate that bacterial communities can be an effective tracer of the origin of invasion and support their potential role in their eukaryotic host's adaptation to new environments. They put forward the critical need to consider the 'meta-organism' encompassing both the host and associated micro-organisms, to unravel the origins, causes and mechanisms underlying biological invasions.
Plos One (1932-6203) (Public Library Science), 2013-07 , Vol. 8 , N. 7 , P. -

Droits : 2013 Aires et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
http://archimer.ifremer.fr/doc/00157/26791/24886.pdf
DOI:10.1371/journal.pone.0068429
http://archimer.ifremer.fr/doc/00157/26791/

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
Heterocyclic aromatic amines (HAA) are formed in cooked meat, poultry and fish but also arise in tobacco smoke and exhaust gases. HAA are potential human carcinogens, which require metabolic activation to exert their genotoxicity. Human tissues can bioactivate HAA to produce reactive intermediates that bind to DNA. HAA DNA adduct formation occurs in human hepatocytes; however, the potential of HAA to form DNA adducts has not been investigated in human T lymphocytes. In this study, we investigated the ability of human T lymphocytes activated with PMA/Ionomycin or CD3/CD28 to express functional CYP1 activity and bioactivate three major HAA: 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-9H-pyrido[2,3-b]indole (AαC) to form DNA adducts. Adducts were measured by ultraperformance liquid chromatography-electrospray ionization/multistage scan mass spectrometry. The highest level of DNA adducts occurred for AαC (16 adducts per 109 nucleotides), followed by PhIP (9 adducts per 109 nucleotides). In contrast, DNA adducts formed from MeIQx and the structurally related aromatic amine 4-aminobiphenyl, a known human carcinogen, were below the limit of detection (< 3 adducts per 109 nucleotides). Moreover, we demonstrate that AαC is a potent inducer of CYP1A1 and CYP1B1 activity through a transcriptional mechanism involving the AhR pathway. Overall, our results highlight the capacity of activated human T lymphocytes to more efficiently bioactivate AαC to form DNA adducts than other prominent HAA or 4-ABP. Environ. Mol. Mutagen. 57:656-667, 2016.
ISSN: 0893-6692

hal-01400486
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01400486
DOI : 10.1002/em.22059
PUBMED : 27801952

Éditeur(s) : HAL CCSD Thieme Publishing
Résumé : International audience
The aim of the present study was to compare the effects of prior cycling and a successive run on respiratory muscle performance during a cycle-run succession as performed in the triathlon. We hypothesized that despite the moderate intensity of exercise and the absence of exhaustion, the crouched cycling position would induce a decrease in respiratory muscle performance that would be reversed by the successive vertical run position. Ten male triathletes (22.6 +/- 1.1 yr) performed a four-trial protocol: (1) an incremental cycle test to assess maximal oxygen uptake (VO2max), (2) 20 min of cycling (C), (3) 20 min of running (R), and (4) 20 min of cycling followed by 20 min of running (C-R). Trials 2, 3 and 4 were performed at the same metabolic intensity, i. e., 75 % of VO2max. Respiratory muscle force was assessed by measuring maximal expiratory (P(Emax)) and inspiratory (P(Imax)) pressures from the functional residual capacity (FRC) before and 10 min after C, R, and C-R. Respiratory muscle endurance was assessed one day before and 30 min after C, R, and C-R, by measuring the time limit (T(lim)), which corresponds to the length of time a respiratory load can be sustained before the process of fatigue develops sufficiently to cause task failure. The results showed a similar significant decrease in P(Imax) (132.4 +/- 4.9 versus 125.7 +/- 5.6 cm H2O, p < 0.05) and T(lim) (5.22 +/- 0.28 versus 3.68 +/- 0.32 min, p < 0.05) post-C and post-C-R (133.7 +/- 4.0 versus 126.9 +/- 5.2 cm H2O, and 5.29 +/- 0.18 versus 3.49 +/- 0.41 min, respectively, p < 0.05) compared with the pre-trial values. In contrast, P(Imax) and T(lim) were not significantly decreased post-R (131.8 +/- 6.1 cm H2O versus 129.6 +/- 6.4 cm H2O, and 4.90 +/- 0.69 versus 4.40 +/- 0.56 min, respectively, p > 0.05). We concluded that moderate intensity exercise not performed to exhaustion induced a decrease in respiratory muscle performance. Moreover, the respiratory muscle fatigue induced by prior cycling was maintained, and neither reversed nor worsened, by the successive run.
ISSN: 0172-4622

hal-00720715
https://hal.univ-antilles.fr/hal-00720715

Éditeur(s) : HAL CCSD
Résumé : International audience
Previous studies have reported respiratory, cardiac and muscle changes at rest in triathletes 24 h after completion of the event. To examine the effects of these changes on metabolic and cardioventilatory variables during exercise, eight male triathletes of mean age 21.1 (SD 2.5) years (range 17-26 years) performed an incremental cycle exercise test (IET) before (pre) and the day after (post) an official classic triathlon (1.5-km swimming, 40-km cycling and 10-km running). The IET was performed using an electromagnetic cycle ergometer. Ventilatory data were collected every minute using a breath-by-breath automated system and included minute ventilation (V(E)), oxygen uptake (VO2), carbon dioxide production (VCO2), respiratory exchange ratio, ventilatory equivalent for oxygen (V(E)/VO2) and for carbon dioxide (V(E)/VCO2), breathing frequency and tidal volume. Heart rate (HR) was monitored using an electrocardiogram. The oxygen pulse was calculated as VO2/HR. Arterialized blood was collected every 2 min throughout IET and the recovery period, and lactate concentration was measured using an enzymatic method. Maximal oxygen uptake (VO2max) was determined using conventional criteria. Ventilatory threshold (VT) was determined using the V-slope method formulated earlier. Cardioventilatory variables were studied during the test, at the point when the subject felt exhausted and during recovery. Results indicated no significant differences (P > 0.05) in VO2max [62.6 (SD 5.9) vs 64.6 (SD 4.8) ml x kg(-1) x min(-1)], VT [2368 (SD 258) vs 2477 (SD 352) ml x min(-1)] and time courses of VO2 between the pre- versus post-triathlon sessions. In contrast, the time courses of HR and blood lactate concentration reached significantly higher values (P < 0.05) in the pre-triathlon session. We concluded that these triathletes when tested 24 h after a classic triathlon displayed their pre-event aerobic exercise capacity, bud did not recover pretriathlon time courses in HR or blood lactate concentration.
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY

hal-00720432
https://hal.univ-antilles.fr/hal-00720432
https://hal.univ-antilles.fr/hal-00720432/document
https://hal.univ-antilles.fr/hal-00720432/file/Article_2.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
The mathematical site of an exercise or a theorem is a useful tool which helps to organize its study, by putting into a hierarchy the various elements (substratum, objects, techniques, technologies) relevant to describe its ecosystem. These characteristics of the mathematical site turn it into a help for the pupil or student (within the framework of an evaluation in mathematics), what we show by the analysis in term of site of a subject given in the competitive ex-amination for secondary school teaching (CAPES) in mathematics. Furthermore, by revealing the organization of a mathematical concept, we show that the site can be a tool for professional training of teachers of mathematics, on the example of the characterization of a constant function on an interval by its derivative.
Le site mathématique local d’un énoncé d’exercice ou d’un théorème de cours se compose d’un système d’êtres mathématiques (objets, techniques, technologies…) et de relations, enrichis par un substrat, formé d’éléments non mathématisables dans l’institution considérée, dévoilant l’organisation de la question. Ces caractéristiques font que le site local fonctionne comme un écosystème, permettant la compréhension d’activités mathématiques de classe, d’évaluation, ce que nous montrons par l’analyse d’un dossier d’oral 2 du CAPES externe de mathématiques. Ce faisant, il devient un outil du professeur pour guider les élèves dans l’étude d’une question. De plus, comme il révèle les organisations locales en mathématiques, le site peut être utilisé comme un outil de formation professionnelle d’enseignants. Par exemple, il permet de questionner les progressions scolaires ou universitaires reçues, ce que nous discutons sur le cas de la caractérisation d’une fonction constante sur un intervalle par sa dérivée.
Repères IREM

hal-01530861
https://hal.univ-antilles.fr/hal-01530861

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Tropical cyclone (TC) waves can severely damage coral reefs. Models that predict where to find such damage (the 'damage zone') enable reef managers to: 1) target management responses after major TCs in near-real time to promote recovery at severely damaged sites; and 2) identify spatial patterns in historic TC exposure to explain habitat condition trajectories. For damage models to meet these needs, they must be valid for TCs of varying intensity, circulation size and duration. Here, we map damage zones for 46 TCs that crossed Australia's Great Barrier Reef from 1985–2015 using three models – including one we develop which extends the capability of the others. We ground truth model performance with field data of wave damage from seven TCs of varying characteristics. The model we develop (4MW) out-performed the other models at capturing all incidences of known damage. The next best performing model (AHF) both under-predicted and over-predicted damage for TCs of various types. 4MW and AHF produce strikingly different spatial and temporal patterns of damage potential when used to reconstruct past TCs from 1985–2015. The 4MW model greatly enhances both of the main capabilities TC damage models provide to managers, and is useful wherever TCs and coral reefs co-occur.
ISSN: 2045-2322

Droits : http://creativecommons.org/licenses/by/
hal-01330362
https://hal-univ-perp.archives-ouvertes.fr/hal-01330362
https://hal-univ-perp.archives-ouvertes.fr/hal-01330362/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01330362/file/srep26009.pdf
DOI : 10.1038/srep26009

Éditeur(s) : HAL CCSD Thieme Publishing
Résumé : International audience
To determine the effect of triathlete performance level on the cardiorespiratory responses elicited by the cycle-run succession, eight regionally and nationally-ranked (Competitive) and five internationally-ranked (Elite) male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 20 min of running (C-R), and 4) a 20-min control run (R) at the same speed as the run in C-R. Before and 10 min after the third and fourth trials the triathletes underwent lung function testing: spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During the C-R trial blood samples were drawn to measure venous lactate concentration. During all trials ventilatory data were collected every minute using an automated breath-by-breath system. The results showed that 1) the oxygen uptake (VO2) of post-cycling running versus running alone was similar for both groups; 2) the ventilatory responses (VE, VE/VO2, VE/VC02 and f) of C-R running versus R were significantly higher (P < 0.005) for the Competitive group; and 3) a significant decrease (P< 0.05) in DL(CO) was also noted after the C-R trial in the Competitive group but not in the Elite group. We concluded that 1) the ventilatory responses during a run subsequent to cycling may be related to the triathlete performance level, and 2) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle alteration and exercise-induced hypoxemia in the Competitive triathletes.
ISSN: 0172-4622

hal-00720719
https://hal.univ-antilles.fr/hal-00720719

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Intraguild predation (IGP) is a type of biological interaction involving the killing and consuming of competing species that exploit similar and often limited resources. This phenomenon is widespread among a great variety of taxonomic groups and has already been reported for mosquito (Diptera: Culicidae) larvae. Moreover, the larvae of certain mosquito species of the tribe Sabethini have evolved modified mouthparts ending in rigid apical structures signaling their capacity to be effective intraguild predators. We assumed that IGP confers a selective advantage under severe competitive conditions by both providing an immediate energetic gain and reducing potential competition. Because potential competition is likely to increase with decreasing habitat size, we hypothesized that the proportion of species with modified mouthparts would increase in smaller aquatic habitats. We tested this hypothesis by examining the mosquito species naturally associated with phytotelmata of decreasing sizes in French Guiana. We show that the degree of specialization in mosquito-phytotelm associations is high, suggesting a long coevolutive process. Indeed, short-term interaction experiments confirmed that species with modified mouthparts are able to prey upon similarly-sized intraguild prey and are, thus, effective intraguild predators. In addition, these species are larger and associated with smaller phytotelmata than those with typical mouthparts. Moreover, below a certain threshold of phytotelm size, only species with modified mouthparts were present. These results show that IGP confers a selective advantage under severe competitive conditions and results from the coadaptation of mosquito species to their specific phytotelm habitat. The presence of functionally analogous structures in different mosquito genera also implies that IGP has emerged from convergent evolution in small phytotelmata.
ISSN: 0269-7653

hal-01603304
https://hal.archives-ouvertes.fr/hal-01603304
DOI : 10.1007/s10682-016-9862-3
PRODINRA : 405771

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Binding of ligand FasL to its receptor Fas triggers apoptosis via the caspase cascade. FasL itself is homotrimeric, and a productive apoptotic signal requires that FasL be oligomerized beyond the homotrimeric state. We generated a series of FasL chimeras by fusing FasL to domains of the Leukemia Inhibitory Factor receptor gp190 which confer homotypic oligomerization, and analyzed the capacity of these soluble chimeras to trigger cell death. We observed that the most efficient FasL chimera, called pFasL, was also the most polymeric, as it reached the size of a dodecamer. Using a cellular model, we investigated the structure-function relationships of the FasL/Fas interactions for our chimeras, and we demonstrated that the Fas-mediated apoptotic signal did not solely rely on ligand-mediated receptor aggregation, but also required a conformational adaptation of the Fas receptor. When injected into mice, pFasL did not trigger liver injury at a dose which displayed anti-tumor activity in a model of human tumor transplanted to immunodeficient animals, suggesting a potential therapeutic use. Therefore, the optimization of the FasL conformation has to be considered for the development of efficient FasL-derived anti-cancer drugs targeting Fas.
ISSN: 1932-6203

hal-00873684
https://hal.archives-ouvertes.fr/hal-00873684
https://hal.archives-ouvertes.fr/hal-00873684/document
https://hal.archives-ouvertes.fr/hal-00873684/file/Functional_Characterization-accepted.pdf
DOI : 10.1371/journal.pone.0054000