Éditeur(s) : Elsevier Science Bv
Résumé : In tropical shrimp ponds, the increasing of feed input, concomitantly with the stocking shrimp biomass, induces an eutrophication of the ecosystem. Although difficult to maintain, its stability is required to guarantee the success of the culture. A 110-day period of phytoplankton and bacterioplankton stock and dynamics in an earthen pond (1.2 ha area, 1 m depth) was monitored using flow cytometry to provide baseline information on community characteristics and ecosystem instability. Seven autotrophic cell types were identified over the whole sampling period. Prokaryotic cells included Synechococcus sp., a group named UNK which presented an atypical new flow cytometric signature and picoeukaryotes (PEUK). Nanophytoplankton cells were represented by 4 groups: NAN1, NAN2, NAN3 and Cryptophytes. During the first part of the survey, picophytoplankton dominated the phytoplanktonic assemblage. The mean abundance of total cells (up to 8 x 10(6) cells mL(-1)) was among the highest recorded in marine and brackish waters. Bacterial abundance and production ranged from 0.8 to 5.1 x 10(7) cells mL(-1) and from 30 to 110 mu g C L-1 h(-1). A shift from pico to nanophytoplankton abundance was observed for a few days from d 96. During this period, heterotrophic bacteria production and abundance suddenly dropped, implying a change in the functioning of the microbial loop. This shift was concomitant with a significant shrimp mortality outbreak due to Vibrio penaeicida, the etiological agent of a disease known as Syndrome 93, which affects the shrimp industry in New Caledonia. This survey suggests that flow cytometric analysis could be used for the monitoring of aquaculture systems to improve our understanding of the complex phytoplankton and bacterial dynamics of these systems and its potential influence on disease development. (c) 2010 Elsevier B.V. All rights reserved.
Aquaculture (0044-8486) (Elsevier Science Bv), 2010-12 , Vol. 310 , N. 1-2 , P. 112-121

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00029/14068/11312.pdf
DOI:10.1016/j.aquaculture.2010.10.022
http://archimer.ifremer.fr/doc/00029/14068/

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
Objectifs. - Évaluer les effets du triathlon classique (1,5 km natation, 40 km cyclisme, 10 km course à pied) sur la capacité de diffusion pulmonaire (DLCO) 24 heures après la compétition. Méthodes et résultats. - Dix triathlètes masculins (21,5 ± 2,8 ans) ont effectué une spirométrie et une mesure de la capacité de diffusion pulmonaire avant la compétition (pré-T) et 24 heures après l'épreuve (post-T). Les résultats montrent une diminution significative du volume expiratoire maximal en 1 s (5,17 ± 0,4 L.s-1 contre 4,09 ± 0,6 L.s-1) et du débit expiratoire maximal 25-75 % de la capacité vitale (6,98 ± 0,2 L.s-1 contre 4,90 ± 0,2 L.s-1). En revanche, les résultats ne montrent pas de différence significative entre les DLCO pré-T et post-T (38,1 ± 3,3 mL.min-1.mmHg-1 contre 37,1 ± 3,7 mL.min-1.mmHg-1) ni les ratios DLCO/VA (5,59 ± 0,5 mL.min-1.mmHg-1.A-1 contre 5,55 ± 0,7 ml.min-1.mmHg-1.A-1). Conclusion. - La DLCO est normale chez les triathlètes 24 heures après une compétition classique. Ceci peut traduire l'absence de lésions alvéolocapillaires pendant le triathlon. La baisse de la DLCO rapportée deux heures après un exercice dans la littérature peut s'expliquer par la baisse du volume sanguin pulmonaire qui apparaît comme un phénomène transitoire. Cependant, la baisse des débits pulmonaires observée 24 heures après le triathlon suggère la persistance chez les triathlètes d'un syndrome obstructif bronchique.
ISSN: 0765-1597

hal-00720522
https://hal.univ-antilles.fr/hal-00720522
https://hal.univ-antilles.fr/hal-00720522/document
https://hal.univ-antilles.fr/hal-00720522/file/Article_3_.pdf

Éditeur(s) : HAL CCSD Wiley Online Library
Résumé : International audience
Zika virus is an Aedes-borne Flavivirus causing fever, arthralgia, myalgia rash, associated with Guillain-Barré syndrome and suspected to induce microcephaly in the fetus. We report here the complete coding sequence of the first characterized Caribbean Zika virus strain, isolated from a patient from Martinique in December, 2015.
ISSN: 2052-2975

hal-01331574
https://hal.archives-ouvertes.fr/hal-01331574
PUBMED : 27274849
PUBMEDCENTRAL : PMC4879239

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The Hedgehog (Hh) family of secreted proteins act as morphogens to control embryonic patterning and development in a variety of organ systems. Post-translational covalent attachment of cholesterol and palmitate to Hh proteins are critical for multimerization and long range signaling potency. However, the biological impact of lipid modifications on Hh ligand distribution and signal reception in humans remains unclear. In the present study, we report a unique case of autosomal recessive syndromic 46,XY Disorder of Sex Development (DSD) with testicular dysgenesis and chondrodysplasia resulting from a homozygous G287V missense mutation in the hedgehog acyl-transferase (HHAT) gene. This mutation occurred in the conserved membrane bound O-acyltransferase (MBOAT) domain and experimentally disrupted the ability of HHAT to palmitoylate Hh proteins such as DHH and SHH. Consistent with the patient phenotype, HHAT was found to be expressed in the somatic cells of both XX and XY gonads at the time of sex determination, and Hhat loss of function in mice recapitulates most of the testicular, skeletal, neuronal and growth defects observed in humans. In the developing testis, HHAT is not required for Sertoli cell commitment but plays a role in proper testis cord formation and the differentiation of fetal Leydig cells. Altogether, these results shed new light on the mechanisms of action of Hh proteins. Furthermore, they provide the first clinical evidence of the essential role played by lipid modification of Hh proteins in human testicular organogenesis and embryonic development.
ISSN: 1553-7390

hal-01063929
https://hal.archives-ouvertes.fr/hal-01063929
DOI : 10.1371/journal.pgen.1004340
PUBMED : 24784881

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Patients with sickle cell anemia (SCA) have usually lower diastolic, systolic and mean blood pressure (BP) than the general population. However, BP values ≥120/70 mmHg considerably increase the risk for acute and chronic complications in SCA. The aim of this study was to identify biological factors associated with relative hypertension in adults with SCA. We compared the hematological, lipid and hemolytic profiles, as well as blood viscosity, between SCA patients with normal BP (<120/70 mmHg, n = 54) and those with relative hypertension (BP≥120/70 mmHg, n = 43). Our results demonstrated that male gender (OR: 3.49; 95%CI 1.20 to 10.16, p<0.05), triglycerides (OR: 9.19; 95% CI 2.29 to 36.95, p<0.01), blood viscosity (OR: 1.35; 95% CI 1.01 to 1.81, p<0.05) and body mass index (OR: 1.37; 95% CI 1.14 to 1.64, p<0.01) were independent risks factors for relative hypertension in SCA. No association was found between the BP status and the positive history of painful vaso-occlusive crisis or acute chest syndrome. An association between triglycerides level and the occurrence of these two major acute complications was detected. Our study suggests that male gender, increased triglycerides level, BMI and blood viscosity could increase the risk for developing relative hypertension in SCA. In addition, our results support a role of moderately elevated triglycerides in the pathophysiology of vaso-occlusive events.
ISSN: 1932-6203

inserm-00838991
http://www.hal.inserm.fr/inserm-00838991
http://www.hal.inserm.fr/inserm-00838991/document
http://www.hal.inserm.fr/inserm-00838991/file/Lamarre_et_al._2013_PloS_ONE_.pdf
DOI : 10.1371/journal.pone.0066004

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
The aim of the present study was to test the effects of hydroxyurea (HU) therapy on clinical, hematological and hemorheological parameters in adult patients with sickle cell anemia (SCA). Hematological and hemorheological parameters were measured in 28 SCA patients before HU therapy (i.e., baseline) and at 6, 12 and 24 months of treatment. RBC deformability was determined by ektacytometry at 30 Pa. RBC aggregation properties were investigated by light-backscatter method. Blood viscosity was measured at 225 s-1 by a cone-plate viscometer. The rates of vaso-occlusive crises and acute chest syndrome were lower at 1 and 2 years of HU therapy compared to baseline. The proportion of patients with leg ulcers tended to decrease after 2 years of treatment. Hemoglobin oxygen saturation improved with HU therapy. HU therapy induced a decrease of platelet and white blood cell counts and a rise in fetal hemoglobin level and mean cell volume. While hemoglobin concentrations increased under HU, blood viscosity remained unchanged all along the study. RBC deformability increased over baseline values at 6 months of HU therapy and continued to rise until the end of the follow-up period. In conclusion, the improvement in RBC deformability probably compensates the increase of hemoglobin on blood viscosity and participates to the improvement of the clinical status of patients.
ISSN: 1386-0291

hal-01668327
https://hal.univ-antilles.fr/hal-01668327
DOI : 10.3233/CH-170280

Éditeur(s) : HAL CCSD
Résumé : National audience
L’objectif était d’identifier des formes d’organisation du travail et d’étudier leur association avec les douleurs de l’épaule et le syndrome de la coiffe des rotateurs (SCR) chez les salariés, à partir des données du programme de surveillance épidémiologique des troubles musculo-squelettiques mis en œuvre dans les Pays de la Loire.
16ème colloque de l'ADEREST
Lyon, France

hal-01301201
https://hal.archives-ouvertes.fr/hal-01301201
DOI : 10.1016/j.admp.2015.04.036

Éditeur(s) : HAL CCSD RNTI
Résumé : International audience
Nous avons tous déjà eu l’occasion d’effectuer des recherches d’ordremédical sur Internet. Si certains sites spécialisés se refusent à tout diagnosticen ligne, préférant le renvoi vers des professionnels de santé, d’autres en revancheconduisent souvent à des déclarations alarmistes faisant état de situationshumaines difficiles. Dans ce travail, nous étudions l’ampleur de ce phénomèneet montrons que quel que soit le syndrome recherché, les résultats obtenusconduisent toujours à l’énoncé des mots "cancer" ou "tumeur".
RNTI. Extraction et Gestion des Connaissances (EGC), Jan 2014, Rennes, France
Rennes, France

hal-01514251
https://hal.archives-ouvertes.fr/hal-01514251

Éditeur(s) : HAL CCSD American Society of Hematology
Résumé : International audience
Zika fever is an Aedes-borne disease caused by a flavivirus (Zika virus, ZIKV, genus Flavivirus). During the past years ZIKV spread in Polynesia, South-America and the Caribbean. Most ZIKV infections are asymptomatic or result in mild febrile disease with rash and conjunctivitis. Attention was recently drawn to non-vectored ZIKV transmission, including sexual, probable blood-borne and mother-to-fetus transmission, and to severe forms such as Guillain-Barré syndrome, acute neurological infections and fetal abnormalities (including microcephaly). Many aspects of Zika fever natural history remain unknown, e.g. the proportion of asymptomatic cases and the duration of viremia. Estimating the prevalence of Zika infections is difficult because a large proportion of infected individuals do not seek medical attention and seroprevalence studies are hampered by antigenic cross-reactivity with other flaviviruses, e.g. dengue virus. Here, we present a study of ZIKV infection in blooddonors from Martinique island (French West Indies, Caribbean region), with novel epidemiological, biological and clinical information that refine the picture of Zika fever in adults.
ISSN: 0006-4971

inserm-01415646
http://www.hal.inserm.fr/inserm-01415646
http://www.hal.inserm.fr/inserm-01415646/document
http://www.hal.inserm.fr/inserm-01415646/file/2016%2C%20Gallian%20et%20al%20-%20Zika%20virus%20in%20asymptomatic%20blood%20donors%2C%20Martinique%20%281%29.pdf
DOI : 10.1182/blood-2016-09-737981

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Functional ecology has long considered the support function as important, but its biomechanical complexity is only just being elucidated. We show here that it can be described on the basis of four biomechanical traits, two safety traits against winds (SW) and self-buckling (SB), and two motricity traits involved in sustaining an upright position, tropic motion velocity (MV) and posture control (PC). All these traits are integrated at the tree scale, combining tree size and shape together with wood properties. The assumption of trait constancy has been used to derive allometric scaling laws, but it was more recently found that observing their variations among environments and functional groups, or during ontogeny, provides more insights into adaptive syndromes of tree shape and wood properties. However, over-simplified expressions have often been used, possibly concealing key adaptive drivers. An extreme case of over-simplification is the use of wood basic density as a proxy for safety. Actually, since wood density is involved in stiffness, loads and construction costs, the impact of its variations on safety is non-trivial. Moreover, other wood features, especially the microfibril angle (MFA), are also involved. Furthermore, wood is not only stiff and strong, but it also acts as a motor for MV and PC. The relevant wood trait for that is maturation strain asymmetry. Maturation strains vary with cell wall characteristics such as MFA, rather than with wood density. Finally, the need for further studies about the ecological relevance of branching patterns, motricity traits and growth responses to mechanical loads is discussed.
ISSN: 0022-0957

hal-00909904
https://hal.archives-ouvertes.fr/hal-00909904
https://hal.archives-ouvertes.fr/hal-00909904/document
https://hal.archives-ouvertes.fr/hal-00909904/file/Integrative_biomechanics_for_tree_Fournier_al.pdf
DOI : 10.1093/jxb/ert279

Résumé : Une étude de typage moléculaire par AP-PCR de souches de Vibrio impliqués dans des épisodes de mortalité d'élevages de crevettes en Nouvelle-Calédonie (Syndrome 93) et au Japon a été réalisée fin 1996 avec le concours de l' Institut Pasteur de Nouvelle-Calédonie. Elle nous a permis une identification rapide des isolats en terme de génospecies ainsi que des discriminations d' intérêt épidémiologique entre les isolats du génospecies majoritaire. Ainsi, des sous-groupes ont été identifiés au sein de l' espéce majoritaire : V. penaeicida. Certains de ces sous-groupes correspondent à des topotypes et permettent de discriminer les isolats du Japon de ceux de Nouvelle-Calédonie, ainsi que ceux de deux baies différentes de Nouvelle Calédonie, distinctes de 50 km seulement. D'autres sous-groupes ont pu être identifiés au sein de l' un des topotypes calédoniens, sans qu'il soit possible de l'expliquer par des éléments épidémiologiques. L' analyse des géotypes et des données zootechniques permettent de qualifier cette vibriose de maladie hydrique, c'est à dire dont le pathogène est véhiculé par l'eau. Des recommandations d' ordre zoosanitaires en sont déduites, qui tendent principalement à limiter les transferts d'animaux entre les différents sites d'élevage. Cette technique d'AP-PCR est utilisée pour la première fois dans l'étude épidémiologique d' une vibriose de crevettes. Sa rapidité, sa fiabilité et les informations d'ordre épidémiologique qu' elle fournit en font une technique de choix pour ce type d'étude

Droits : 1997 Ifremer
http://archimer.ifremer.fr/doc/00274/38541/37061.pdf
http://archimer.ifremer.fr/doc/00274/38541/

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
BACKGROUND/AIM: Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue. METHODS: We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients. RESULTS: Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects. CONCLUSIONS: Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit mitochondrial respiration but increases muscle microvascular blood flow.
ISSN: 1932-6203

inserm-00849035
http://www.hal.inserm.fr/inserm-00849035
http://www.hal.inserm.fr/inserm-00849035/document
http://www.hal.inserm.fr/inserm-00849035/file/2013_Waltz_-_Normal_muscle_oxygen_consumption_and_fatigability_in_sickle_cell_patients.pdf
DOI : 10.1371/journal.pone.0052471

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Trivalent inorganic arsenic [As(III)] is an efficient anticancer agent used to treat patients suffering from acute promyelocytic leukemia. Recently, experimental studies have clearly demonstrated that this metalloid can also cure lymphoproliferative and/or pro-inflammatory syndromes in different murine models of chronic immune-mediated diseases. T helper (Th) 1 and Th17 lymphocytes play a central role in development of these diseases, in mice and humans, especially by secreting the potent pro-inflammatory cytokine interferon-γ and IL-17A, respectively. As(III) impairs basic functions of human T cells but its ability to modulate secretion of pro-inflammatory cytokines by differentiated Th lymphocytes is unknown. In the present study, we demonstrate that As(III), used at concentrations clinically achievable in plasma of patients, has no effect on the secretion of interferon-γ from Th1 cells but almost totally blocks the expression and the release of IL-17A from human Th17 lymphocytes co-stimulated for five days with anti-CD3 and anti-CD28 antibodies, in the presence of differentiating cytokines. In addition, As(III) specifically reduces mRNA levels of the retinoic-related orphan receptor (ROR)C gene which encodes RORγt, a key transcription factor controlling optimal IL-17 expression in fully differentiated Th17 cells. The metalloid also blocks initial expression of IL-17 gene induced by the co-stimulation, probably in part by impairing activation of the JNK/c-Jun pathway. In conclusion, our results demonstrate that As(III) represses expression of the major pro-inflammatory cytokine IL-17A produced by human Th17 lymphocytes, thus strengthening the idea that As(III) may be useful to treat inflammatory immune-mediated diseases in humans.
ISSN: 0041-008X

inserm-00872871
http://www.hal.inserm.fr/inserm-00872871
DOI : 10.1016/j.taap.2012.05.004
PUBMED : 22617429

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
Patients with hemoglobin C disease (CC) usually do not develop severe complications in comparison with individuals with sickle cell anemia (SS) or with sickle cell hemoglobin C disease (SC). The present study compared the hematological, biochemical, hemorheological and clinical characteristics of CC patients to those of SS, SC and healthy individuals (AA). Blood viscosity was measured at 225 s(-1) with a cone plate viscometer. The hematocrit-to-blood viscosity ratio (HVR), i.e. an index of red blood cell (RBC) oxygen transport effectiveness, was calculated. RBC deformability was determined at 30 Pa by ektacytometry, and RBC aggregation properties by syllectometry. CC and SC had higher blood viscosity and lower HVR than AA. Nevertheless, HVR was higher in CC compared to SS and tended to be higher than in SC. The CC group exhibited very rigid hyperchromic RBC compared to the three other groups. RBC aggregation abnormalities were observed in CC: low RBC aggregation index and high RBC aggregates strength. Despite these hemorheological abnormalities, CC never had hospitalized painful vaso-occlusive crisis or acute chest syndrome. In contrast, all of them had splenomegaly. Of note, 2 out of 7 CC developed retinopathy or otologic disorders. Whether the blood hyperviscosity and decreased RBC deformability are responsible for these complications is unknown. The higher oxygen transport effectiveness (i.e., HVR) of CC compared to SS is probably at the origin of the very low risk of medical complication in this population.
ISSN: 1386-0291

hal-01668336
https://hal.univ-antilles.fr/hal-01668336
DOI : 10.3233/CH-141906

Éditeur(s) : HAL CCSD
Résumé : National audience
Objectif L’objectif était d’identifier des formes d’organisation du travail et d’étudier leur association avec les douleurs de l’épaule et le syndrome de la coiffe des rotateurs (SCR) chez les salariés, à partir des données du programme de surveillance épidémiologique des troubles musculo-squelettiques mis en œuvre dans les Pays de la Loire. Méthodes Entre 2002 et 2005, la participation volontaire de 83 médecins du travail a permis d’inclure par tirage au sort 3710 salariés lors de leur visite médicale périodique. Seize variables organisationnelles ont été recueillies par auto-questionnaire. Les symptômes de l’épaule ont été recueillis à l’aide d’un questionnaire de type nordique et le SCR a été diagnostiqué par le médecin à l’aide d’un examen clinique standardisé. Une classification ascendante hiérarchique (CAH) des variables organisationnelles puis des salariés ont permis d’identifier les différentes formes d’organisation du travail. Les associations entre les formes d’organisation du travail et les douleurs de l’épaule et le SCR ont été étudiées par des régressions logistiques ajustées sur des facteurs individuels, biomécaniques et psychosociaux. Résultats Cinq classes d’organisation du travail ont été identifiées. Une classe de salariés s’est révélée fortement exposée aux contraintes organisationnelles : – travail en équipe postée ; – polyvalence ; – faible latitude décisionnelle ; – répétitivité des tâches ; – rythme de travail imposé par : – le déplacement automatique d’un produit ou d’une pièce/la cadence automatique d’une machine, – la dépendance immédiate vis-à-vis du travail des collègues, – des normes de production ou des délais à respecter, – des contrôles ou une surveillance permanents. À l’inverse, elle était moins exposée au rythme de travail imposé par une demande extérieure (public, client) que l’ensemble de l’échantillon. Par rapport à cette classe, les salariés des quatre autres classes avaient un risque plus faible de douleurs de l’épaule au cours des 12 derniers mois (OR de 0,6 [0,5–0,7] à 0,8 [0,6–0,9]), permanentes au cours des 12 derniers mois (OR de 0,6 à 0,8 [0,5–1,0]) et au cours des 7 derniers jours (OR de 0,6 [0,4–0,9], à 0,8 [0,6–1,0]). L’association était non significative pour le SCR (p = 0,11). Conclusions L’étude a montré une association significative entre les douleurs de l’épaule et l’exposition à des contraintes organisationnelles. Ces résultats seront à confirmer à l’aide de modèles à équations structurelles
16e colloque scientifique de l’ADEREST
Lyon, France

hal-01187141
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187141
DOI : 10.1016/j.admp.2015.04.036

Éditeur(s) : HAL CCSD American Society of Hematology
Résumé : International audience
Human immunodeficiency virus (HIV)-associated disseminated Histoplasma capsulatum capsulatum infection often mimics tuberculosis. This disease is well know in the United States but is dramatically underdiagnosed in Central and South America. In the Amazon region, given the available incidence data and the regional HIV prevalence, it is expected that, every year, 1,500 cases of histoplasmosis affect HIV patients in that region alone. Given the mortality in undiagnosed patients, at least 600 patients would be expected to die from an undiagnosed but treatable disease. The lack of a simple diagnostic tool and the lack of awareness by clinicians spiral in a vicious cycle and made a major problem invisible for 30 years. The HIV/acquired immunodeficiency syndrome community should tackle this problem now to prevent numerous avoidable deaths from HIV-associated histoplasmosis in the region and elsewhere.
ISSN: 0006-4971

inserm-00913874
http://www.hal.inserm.fr/inserm-00913874
http://www.hal.inserm.fr/inserm-00913874/document
http://www.hal.inserm.fr/inserm-00913874/file/2013_Nacher_-_How_many_have_died_from_undiagnosed_histoplasmosis.pdf
DOI : 10.4269/ajtmh.13-0226

Résumé : Une expérience a été réalisée en conditions hivernales dans six bassins de terre pour déterminer l'effet des taux de renouvellement sur la production de crevettes Penaeus stylirostris, sur les caractéristiques de l'eau et du sédiment des enceintes d'élevage. Les budgets d'azote ont été établis en prenant en compte les différentes formes azotées dans l'eau, dans le sédiment, dans l'aliment et dans les crevettes. Un épisode de mortalité a été obserVé en cours d'élevage et peut être attribué à une epizootie dénommée "syndrome 93». Ce dernier était concomitant à une phase de croissance phytoplantonique et a été d'autant plus important que la biomasse phytoplanctonique dans le bassin d'élevage était élevée. Bien qu'une dilution importante de la colonne d'eau se soit avérée bénéfique pour la santé du cheptel pendant l'épisode de mortalité, l'augmentation des taux de renouvellement n'a en revanche pas permis d'améliorer de manière significative la qualité de l'environnement crevette sur toute la saison d'élevage (eau et sédiment). Une augmentation des échanges d'eau ne s'est pas accompagnée d'une meilleure exportation des déchets par les effluents. Cependant, les résultats montrent que cette augmentation accroît la productivité primaire. Les composés issus de la minéralisation de la matière organique et du métabolisme sont ainsi exportés sous forme particulaire plutôt que sous forme soluble. Les budgets d'azote montrent que la quantité de déchets rejetés par les effluents vers l'environnement côtier est faible. Ainsi, 10,1% à 16,90/o de l'azote introduit dans le milieu d'élevage sous forme d'aliment est exporté dans les effluents. Seulement 17,3% à 21,4% de l'azote d'origine alimentaire est retrouvé dans la chair des crevettes. L'augmentation des échanges d'eau implique une augmentation de l'accumulation azotée dans les sédiments de 21,0% à 50,1%. Parallèlement, le calcul de la proportion d'azote évacué par diffusion ou par dénitrification vers l'atmosphère diminue de 43,1% à 19,5% avec l'augmentation des taux de renouvellement.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00079/19066/16661.pdf
http://archimer.ifremer.fr/doc/00079/19066/

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
STUDY QUESTION: Is there evidence at the population level of associations between different male genital disorders, outside Scandinavian countries? SUMMARY ANSWER: At an international scale, there is evidence for a number of correlations between rates of four male reproductive disorders (hypospadias, cryptorchidism, testicular cancer and low sperm concentration). WHAT IS KNOWN ALREADY: Some associations between these outcomes have been shown in studies focusing on individuals and mainly in Nordic European countries. These associations, together with histological evidence of a dysgenesis pattern in testicular tissue specimens, have generated the concept of the existence of a 'testicular dysgenesis syndrome' originating in utero. STUDY DESIGN, SIZE, DURATION: This is a geographical correlation study using cancer, malformations rates and sperm quality data collected between the years 1998 and 2005. PARTICIPANTS/MATERIALS, SETTING, METHODS: Incidence rates of testicular cancer were extracted from International Agency for Research on Cancer registries and Globocan, while cryptorchidism and hypospadias prevalence rates were obtained from EUROCAT and International Clearinghouse for Birth Defects Surveillance and Research registries. Sperm concentration data were extracted from recent studies using standardized methodology. A total of 39 registries and 9 sperm studies were selected. Non-parametric Spearman correlation tests were used to test the association between these four disorders. Correlations were computed for all registries together, for registries with high-quality matching coverage only and by continents. Sensitivity analyses were also conducted using data from prospective clinical studies to take into account potential bias related mainly to ascertainment of malformation rates. MAIN RESULTS AND THE ROLE OF CHANCE: We found positive correlations between testicular cancer and hypospadias (r = 0.32, P = 0.05) and between hypospadias and cryptorchidism (r = 0.70, P = 0.008). Stronger correlations were observed when using registries with high-quality matching coverage. Among these registries, differences between Europe and the rest of the world appeared (the positive correlation between testicular cancer and cryptorchidism was stronger outside Europe, r = 0.83, P = 0.01 compared with 0.40, P = 0.60 for European registries). A negative correlation between testicular cancer and sperm concentration was observed (r = -0.88, P = 0.002). These correlations support our initial hypothesis but remain only suggestive due to the intrinsic limitations in the study design (i.e. geographical correlation study) and do not allow causal inference. LIMITATIONS, REASONS FOR CAUTION: Differences in the ascertainment of malformations rates (definition, length of follow-up) make the international comparison difficult. The small number of registries for some conditions (cryptorchidism) or of studies (for sperm quality) and the absence of information about major risk factors such as ethnicity and socioeconomic status in the registries are also limitations. WIDER IMPLICATIONS OF THE FINDINGS: Our findings are in agreement with results of studies focusing on individuals and suggest that shared risk factors are present in the populations studied.
ISSN: 0268-1161

inserm-00863412
http://www.hal.inserm.fr/inserm-00863412
DOI : 10.1093/humrep/det111
PUBMED : 23670171

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Ants figure prominently among the worst invasive species because of their enormous ecological and economic impacts. However, it remains to be investigated which species would be behaviourally dominant when confronted with another invasive ant species, should two species be introduced in the same area. In the future, many regions might have suitable environmental conditions for several invasive ant species, as predicted under climate change scenarios. Here, we explored interactions among several highly invasive ant species, which have been shown to have overlapping suitable areas. The aim of this study was to evaluate the performance in interference competition of seven of the world's worst invasive ant species (Anoplolepis gracilipes, Paratrechina longicornis, Myrmica rubra, Linepithema humile, Lasius neglectus, Wasmannia auropunctata and Pheidole megacephala). We conducted pairwise confrontations, testing the behaviour of each species against each of the six other species (in total 21 dyadic confrontations). We used single worker confrontations and group interactions of 10 versus 10 individuals to establish a dominance hierarchy among these invasive ant species. We discovered two different behavioural strategies among these invasive ants: three species displayed evasive or indifferent behaviour when individuals or groups were confronted (A. gracilipes, Pa. longicornis, M. rubra), while the four remaining species were highly aggressive during encounters and formed a linear dominance hierarchy. These findings contrast with the widespread view that invasive ants form a homogeneous group of species displaying the `invasive syndrome', which includes generally aggressive behaviour. The dominance hierarchy among the four aggressive species may be used to predict the outcome of future competitive interactions under some circumstances. Yet, the existence of several behavioural strategies renders such a prediction less straightforward.
ISSN: 1387-3547

hal-01444816
https://hal.archives-ouvertes.fr/hal-01444816
DOI : 10.1007/s10530-015-0892-5

Éditeur(s) : Elsevier
Résumé : Vibriosis is a major disease problem in shrimp aquaculture, affecting all developmental stages, from larvae in hatchery tanks to juveniles and broodstock in growout ponds. However, bacterial strains responsible for vibriosis in the successive stages are usually considered to be different, and virulence specificity has been reported both at the species and at the stage levels. The so-called « Syndrome 93 » is a seasonal juvenile vibriosis caused by Vibrio penaeicida which affects Penaeus stylirostris in growout ponds and broodstock tanks in New Caledonia. This pathology does not cause any mortality in hatchery or nursery phases. An experimental infection design using balneation of postlarvae and early juveniles in V. penaeicida suspensions was used to evaluate the developmental stage at which shrimp become sensitive to this vibriosis. We demonstrated that the acquisition of susceptibility to this pathogen is very sudden and correlated with the acquisition of the definitive rostral formula, and from this draw conclusions regarding virulence mechanisms of V. penaeicida in P. stylirostris.
Aquaculture (Elsevier), 1998-12 , Vol. 169 , N. 3-4 , P. 291-296

Droits : 1998 Elsevier Science B.V. All rights reserved
http://archimer.ifremer.fr/doc/1998/publication-383.pdf
DOI:10.1016/S0044-8486(98)00380-9
http://archimer.ifremer.fr/doc/00000/383/