Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Maternal affective disorders are frequently treated with selective serotonin reuptake inhibitor medications (SSRIs); with up to 10% of women being prescribed these medications during pregnancy. Infant development depends on the early serotonergic environment, which is altered by perinatal SSRIs, raising concern about how these medications affect neural outcomes. While clinical and preclinical research suggests an impact of SSRIs on the developing brain, more research is needed to determine the effects on neuroplasticity, the serotonergic system, and the hypothalamic-pituitary-adrenal axis in neural regions mediating behavior. The current work investigated the effects of the SSRI, fluoxetine, on the serotonergic system in the prefrontal cortex (PFC) during pre-adolescence, and changes to synaptic markers and glucocorticoid receptor density in the cingulate cortex (medial PFC) of pre-adolescent and adult Sprague-Dawley male and female rats. To model aspects of Perinatal Depression and maternal anxiety, pre-gestational maternal stress was used resulting in male and female offspring from 4 groups: 1) control, 2) perinatal fluoxetine exposed, 3) pre-gestational maternal stress exposed, and 4) pre-gestational maternal stress + fluoxetine. Perinatal fluoxetine prevented the effects of maternal stress on 5-HT levels and 5-HT turnover ratio in the PFC of pre-adolescent offspring, particularly in females. However, pre-gestational stress reduced synaptophysin and PSD-95 densities in the cingulate cortex, effects that were more pronounced in males. Interestingly, perinatal fluoxetine exposure reduced GR density in adult males in this same brain area. Together, results show differential effects of perinatal SSRIs and pre-gestational maternal stress on neurodevelopment in the PFC of males and females.
ISSN: 0028-3908

hal-01647158
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647158
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647158/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647158/file/Gemmel%20-%20Perinatal%20fluoxetine%20prevents%20the%20effect.pdf
DOI : 10.1016/j.neuropharm.2017.10.009

Éditeur(s) : ISTPM
Résumé : The Thalassa, a ship of the Institute of Fishing, carried out two trawling campaigns off the coasts of Rio de Oro, Mauritania and Senegal. The first one took place in November and December 1962; it extended from Cape Juby to Tamxat (17°20'N). The second, directed more towards the south, reached the Fosse de Cayar Submarine Canyon, near Cape Verde; it occurred in March and April 1968. These operations represent in total 100 trawl passes between latitudes 15° and 28°N and depths of 10 to 800 metres. These two campaigns' overall data are introduced incidentally. The data recorded here are exclusively about the twenty species of sparidae harvested. They concern the geographic and bathymetric distribution, frequency and numbers, size and sex. There emerge certain comments on the animal life, biology and fishing. In some cases, it seemed worthwhile to emphasise the morphological differences that make it possible to distinguish among them species at times very closely related.
La « Thalassa », navire de l'Institut des Pêches, a effectué deux campagnes de chalutage au large des côtes du Rio de Oro, de la Mauritanie et du Sénégal. La première a eu lieu en novembre et décembre 1962; elle s'est étendue du cap Juby à Tamxat (17°20'N). La seconde, plus orientée vers le sud, a atteint la fosse de Cayar, à proximité du cap Vert; elle s'est déroulée en mars et avril 1968. Ces opérations représentent au total cent traicts de chalut qui se répartissent entre les latitudes 15° et 28°N et les profondeurs de 10 à 800 m. Les données d'ensemble de ces deux campagnes sont présentées par ailleurs. Celles consignées ici concernent exclusivement les vingt espèces de sparidés récoltées. Elles ont trait à la répartition géographique et bathymétrique, la fréquence et l'abondance, la taille et le sexe. Il s'en dégage certaines remarques sur la faunistique, la biologie et la pêche. Dans certains cas il a paru intéressant de souligner les différences morphologiques qui permettent de distinguer, entre elles, des espèces parfois très voisines.(OCR non controlé)
Revue des Travaux de l'Institut des Pêches Maritimes (0035-2276) (ISTPM), 1969-03 , Vol. 33 , N. 1 , P. 97-116

Droits : Ifremer
http://archimer.ifremer.fr/doc/1969/publication-3156.pdf
http://archimer.ifremer.fr/doc/00000/3156/

Éditeur(s) : HAL CCSD
Résumé : International audience
BACKGROUND: Numerous studies have linked prenatal traffic-related air pollution exposure to fetal growth. Recently, several studies have suggested exploring this association independently among boys and girls because of potential sex-specific biological vulnerability to air pollution. Residence-based factors can also influence fetal growth by enhancing susceptibility to the toxic effects of air pollution and must also be considered in these relations. OBJECTIVE: We examined sex-specific associations between prenatal air pollution exposure and fetal growth and explored whether they differed by the urban-rural status of maternal residence. METHODS: This study relied on the PELAGIE mother-child cohort (2521 women, Brittany, France, 2002-2006). Fetal growth was assessed through birth weight, head circumference and small weight (SGA) and small head circumference (SHC) for gestational age. Nitrogen dioxide (NO2) concentrations at mothers' homes were estimated by using a land use regression model taking into account temporal variation during pregnancy. Associations between estimated NO2 concentrations and fetal growth were assessed with linear regression or logistic regression models, depending on the outcome investigated. RESULTS: An interquartile range (8.8µgm(-3)) increase in NO2 exposure estimates was associated with a 27.4g (95% CI 0.8 to 55.6) increase in birth weight and a 0.09cm (95% CI 0.00-0.17) significant increase in head circumference, among newborn boys only. Their risks of SGA and SHC were reduced (OR 0.70, 95% CI 0.53-0.92, OR 0.76, 95% CI 0.56-1.03, respectively, for an increase of 8.8µgm(-3)). No statistically significant trends were observed among girls. Urban-rural status modified the effect of air pollution only for SHC and again only for newborn boys. CONCLUSION: Findings from this study confirm the need to consider sex-specific associations between air pollution and fetal growth and to investigate possible mechanisms by which traffic-related air pollution may increase anthropometric parameters at birth
Environmental Research

hal-01205354
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01205354
DOI : 10.1016/j.envres.2015.09.006
PUBMED : 26378737

Éditeur(s) : HAL CCSD Hindawi Publishing Corporation
Résumé : International audience
Two genes, that is, 5S ribosomal sequences and antifreeze glycoprotein (AFGP) genes, were mapped onto chromosomes of eight Antarctic notothenioid fish possessing a X1X1X2X2/X1X2Y sex chromosome system, namely, Chionodraco hamatus and Pagetopsis macropterus (family Channichthyidae), Trematomus hansoni, T. newnesi, T. nicolai, T. lepidorhinus, and Pagothenia borchgrevinki (family Nototheniidae), and Artedidraco skottsbergi (family Artedidraconidae). Through fluorescence in situ hybridization (FISH), we uncovered distinct differences in the gene content of the Y chromosomes in the eight species, with C. hamatus and P. macropterus standing out among others in bearing 5S rDNA and AFGP sequences on their Y chromosomes, respectively. Both genes were absent from the Y chromosomes of any analyzed species. The distinct patterns of Y and non-Y chromosome association of the 5S rDNA and AFGP genes in species representing different Antarctic fish families support an independent origin of the sex heterochromosomes in notothenioids with interesting implications for the evolutionary/adaptational history of these fishes living in a cold-stable environment.
ISSN: 2314-6133

hal-01544911
https://hal.archives-ouvertes.fr/hal-01544911
DOI : 10.1155/2013/243938

Éditeur(s) : Edp Sciences S A
Résumé : This study was designed to measure responses of four-year-old black-lip pearl oysters (Pinctada margaritifera) to different temperatures and food concentrations and to identify the energy requirements of each sex. Oysters were fed a monospecific microalgal diet of Isochrysis affinis galbana (T-iso). Measurements of oxygen consumption and ingestion rates were carried out at 24 degrees C and 27 degrees C and at two algal (T-iso) concentrations: 5000 and 30 000 cell ml(-1). Glycogen content in adductor muscle, absorption efficiency and scope for growth were also estimated. Females and males responded differently to environmental factors, with food level being the most influential parameter. Oxygen consumption and absorption efficiency were significantly higher in females than in males, but males had significantly higher glycogen content than females. At high food concentration, glycogen content, ingestion rate, oxygen consumption, and scope for growth were significantly higher than at the low food concentration. Only absorption efficiency was significantly higher at the low food concentration. Oxygen consumption was significantly higher at 27 degrees C than at 24 degrees C. These results indicate that females and males have different bioenergetic functioning and that energy demands for reproduction are higher in females.
Aquatic Living Resources (0990-7440) (Edp Sciences S A), 2013-07 , Vol. 26 , N. 3 , P. 263-271

Droits : EDP Sciences, IFREMER, IRD 2013
http://archimer.ifremer.fr/doc/00157/26855/24980.pdf
DOI:10.1051/alr/2013059
http://archimer.ifremer.fr/doc/00157/26855/

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
With the growing use of selective serotonin reuptake inhibitor medications (SSRIs) for the treatment of depression during the perinatal period, questions have been raised about the longterm impact of these medications on development. We aimed to investigate how developmental SSRI exposure may alter affect-related behaviors and associated molecular processes in offspring using a rodent model of maternal stress and depression. For this purpose, prenatally stressed or non-stressed male offspring were exposed to fluoxetine (5 mg/kg/day) or vehicle, via lactation, until weaning. Primary results show that postnatal fluoxetine exposure differentially altered anxiety-like behavior by increasing anxiety in non-stressed offspring and decreasing anxiety in prenatally stressed offspring. In the hippocampus, developmental fluoxetine exposure decreased BDNF IV and TrkB mRNA expression. Prenatal stress alone also decreased escape behaviors and decreased hippocampal BDNF IV mRNA expression. These data provide important evidence for the long-term programming effects of early-life exposure to SSRIs on brain and behavior.
ISSN: 0012-1630

hal-01305478
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01305478
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01305478/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01305478/file/Developmental%20SSRIs%2C%20anxiety%20and%20BDNF_accepted.pdf
DOI : 10.1002/dev.21385

Éditeur(s) : HAL CCSD Seismological Society of America
Résumé : Shear-wave splitting measurements are widely used to analyze orientations of anisotropy. We compare two different shear-wave splitting techniques, which are generally assumed to give similar results. Using a synthetic test, which covers the whole backazimuthal range, we find characteristic differences, however, in fast-axis and delay-time estimates near Null directions between the rotation correlation and the minimum energy method. We show how this difference can be used to identify Null measurements and to determine the quality of the result. This technique is then applied to teleseismic events recorded at station LVZ in northern Scandinavia, for which our method constrains the fast-axis azimuth to be 15° and the delay time 1.1 sec.
ISSN: 0037-1106

hal-00404493
https://hal.archives-ouvertes.fr/hal-00404493
DOI : 10.1785/0120060190

Éditeur(s) : HAL CCSD John Wiley & Sons
Résumé : International audience
Kisspeptins are now considered key players in the neuroendocrine control of puberty and reproduction, at least in mammals. Most teleosts have two kiss genes, kiss1 and kiss2, but their sites of expression are still poorly documented. As a first step in investigating the role of kisspeptins in the European sea bass, a perciform fish, we studied the distribution of kiss1 and kiss2-expressing cells in the brain of males and females undergoing their first sexual maturation. Animals were examined at early and late in the reproductive season. We also examined the putative expression of estrogen receptors in kiss-expressing cells and, finally, we investigated whether kisspeptins are expressed in the pituitary gland. We show that kiss1-expressing cells were consistently detected in the habenula and, in mature males and females, in the rostral mediobasal hypothalamus. In both sexes, kiss2-expressing cells were consistently detected at the level of the preoptic area, but the main kiss2 mRNA-positive population was observed in the dorsal hypothalamus, above and under the lateral recess. No obvious sexual differences in kiss1 and kiss2 mRNA expression were detected. Additional studies based on confocal imaging clearly showed that most kiss1 mRNA-containing cells of the mediobasal hypothalamus strongly express ERα and slightly express ERβ2. At the pituitary level, both sexes exhibited kiss1 mRNA expression in most FSHβ-positive cells and never in LHβ-positive cells.
ISSN: 0092-7317

hal-00877326
https://hal.archives-ouvertes.fr/hal-00877326
PUBMED : 22886357
DOI : 10.1002/cne.23211

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Climatic changes result in an increased in mean temperature and in a higher incidence of extreme weather events such as heat and cold waves. For ectotherms, such as insect parasitoids, the ability to remain active under extreme climatic conditions is a significant key to fitness. The body size of individuals, and in particular their surface to volume ratio, may play a role in their resistance to thermal conditions. The thermal tolerances are investigated of two closely-related sympatric parasitoid species [Aphidius avenae Haliday and Aphidius rhopalosiphi De Stefani-Perez (Hymenoptera: Aphidiinae)] that have a similar ecology but differ in body size and phenologies. The critical thermal limits of individuals are assessed in both sexes of each parasitoid species and the influence of surface-volume ratios on their thermal tolerances. Aphidius avenae is less resistant to low temperatures and more resistant to high temperatures than A. rhopalosiphi. The lower surface to volume ratio of A. avenae individuals may help them to remain active in summer when experiencing heat waves. However, body size is not the sole factor that plays a role in differences of thermal tolerance between species and body size may not be an adaptation to extreme temperatures but rather a by-product of developmental regulation. Closely related sympatric species from the same ecological guild can have different thermal tolerances that may allow them to occur within the same habitat. The present study also highlights the importance of clearly defining how to measure critical thermal limits to determine the thermal tolerance of a species.
ISSN: 0307-6962

hal-00589094
https://hal.archives-ouvertes.fr/hal-00589094
DOI : 10.1111/j.1365-3032.2010.00758.x

Éditeur(s) : HAL CCSD Society for the Study of Reproduction
Résumé : International audience
Transcription factor GATA4 is required for the development and function of the mammalian gonads. We first reported that the GATA4 gene in both human and rodents is expressed as two major alternative transcripts that differ solely in their first untranslated exon (exon 1a vs. exon 1b). We had also showed by quantitative PCR that in mouse tissues, both Gata4 exon 1a- and 1b-containing transcripts are present in all sites that are normally positive for GATA4 protein. In adult tissues, exon 1a-containing transcripts generally predominate. A notable exception, however, is the testis where the Gata4 exon 1a and 1b transcripts exhibit a similar level of expression. We now confirm by in situ hybridization analysis that each transcript is also strongly expressed during gonad differentiation in both sexes in the rat. To gain further insights into how Gata4 gene expression is controlled, we characterized the mouse Gata4 promoter sequence located upstream of exon 1b. In vitro studies revealed that the Gata4 1b promoter is less active than the 1a promoter in several gonadal cell lines tested. Whereas we have previously shown that endogenous Gata4 transcription driven by the 1a promoter is dependent on a proximally located Ebox motif, we now show using complementary in vitro and in vivo approaches that Gata4 promoter 1b-directed expression is regulated by GATA4 itself. Thus, Gata4 transcription in the gonads and other tissues is ensured by distinct promoters that are regulated differentially and independently.
ISSN: 0006-3363

hal-01010626
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01010626
DOI : 10.1095/biolreprod.113.113290
PUBMED : 24352556

Éditeur(s) : HAL CCSD
Résumé : International audience
The SOX8 and SOX9 transcription factors are involved in, among others, sex differentiation, male gonad development and adult maintenance of spermatogenesis. Sox8(-/-) mice lacking Sox9 in Sertoli cells fail to form testis cords and cannot establish spermatogenesis. Although genetic and histological data show an important role for these transcription factors in regulating spermatogenesis, it is not clear which genes depend upon them at a genome-wide level. To identify transcripts that respond to the absence of Sox8 in all cells and Sox9 in Sertoli cells we measured mRNA concentrations in testicular samples from mice at 0, 6 and 18 days post-partum. In total, 621 and 629 transcripts were found at decreased or increased levels, respectively, at different time points in the mutant as compared to the control samples. These mRNAs were categorized as preferentially expressed in Sertoli cells or germ cells using data obtained with male and female gonad samples and enriched testicular cell populations. Five candidate genes were validated at the protein level. Furthermore, we identified putative direct SOX8 and SOX9 target genes by integrating predicted SOX-binding sites present in potential regulatory regions upstream of the transcription start site. Finally, we used protein network data to gain insight into the effects on regulatory interactions that occur when Sox8 and Sox9 are absent in developing Sertoli cells. The integration of testicular samples with enriched Sertoli cells, germ cells and female gonads enabled us to broadly distinguish transcripts directly affected in Sertoli cells from others that respond to secondary events in testicular cell types. Thus, combined RNA profiling signals, motif predictions and network data identified putative SOX8/SOX9 target genes in Sertoli cells and yielded insight into regulatory interactions that depend upon these transcription factors. In addition, our results will facilitate the interpretation of genome-wide in vivo SOX8 and SOX9 DNA binding data.
Andrology

hal-00877013
https://hal.archives-ouvertes.fr/hal-00877013
DOI : 10.1111/j.2047-2927.2012.00049.x
PUBMED : 23315995

Éditeur(s) : Elsevier
Résumé : Bioaccumulation is difficult to document because responses differ among chemical compounds, with environmental conditions, and physiological processes characteristic of each species. We use a mechanistic model, based on the Dynamic Energy Budget (DEB) theory, to take into account this complexity and study factors impacting accumulation of organic pollutants in fish through ontogeny. The bioaccumulation model proposed is a comprehensive approach that relates evolution of hake PCB contamination to physiological information about the fish, such as diet, metabolism, reserve and reproduction status. The species studied is the European hake (Merluccius merluccius, L. 1758). The model is applied to study the total concentration and the lipid normalised concentration of 4 PCB congeners in male and female hakes from the Gulf of Lions (NW Mediterranean sea) and the Bay of Biscay (NE Atlantic ocean). Outputs of the model compare consistently to measurements over the life span of fish. Simulation results clearly demonstrate the relative effects of food contamination, growth and reproduction on the PCB bioaccumulation in hake. The same species living in different habitats and exposed to different PCB prey concentrations exhibit marked difference in the body accumulation of PCBs. At the adult stage, female hakes have a lower PCB concentration compared to males for a given length. We successfully simulated these sex-specific PCB concentrations by considering two mechanisms: a higher energy allocation to growth for females and a transfer of PCBs from the female to its eggs when allocating lipids from reserve to eggs. Finally, by its mechanistic description of physiological processes, the model is relevant for other species and sets the stage for a mechanistic understanding of toxicity and ecological effects of organic contaminants in marine organisms.
Journal of Sea Research (1385-1101) (Elsevier), 2009-10 , Vol. 62 , N. 2-3 , P. 124-134

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6789.pdf
DOI:10.1016/j.seares.2009.02.006
http://archimer.ifremer.fr/doc/00000/6789/

Éditeur(s) : Soc Francaise D Ichtyologie
Résumé : Age is a necessary parameter used in population dynamics to assess the state of exploited resources. This parameter is poorly known for most deep-sea species (depth > 400 m). This work focused on age estimation from otoliths of Alepocephalus bairdii (Alepocephalidae), Coryphaenoides rupestris (Macrouridae), Helicolenus dactylopterus (Sebastidae) and Hoplostethus atlanticus (Trachichthyidae), which French fishery exploitation, off the west coasts of the British Isles, began the late 1980's. Considering otolith growth zones as annual, the four species all show high longevity: 38, 54, 43 and 130 years, respectively, together with slow growth. The differences in growth between sex were estimated and difficulties in accurately estimating the age were highlighted and showed the need to standardise and validate age estimation. The ages currently estimated for deep-sea fish must be used with caution.
Cybium (0399-0974) (Soc Francaise D Ichtyologie), 2000 , Vol. 24 , N. 3 , P. 7-16

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00000/10396/7690.pdf
http://archimer.ifremer.fr/doc/00000/10396/

Éditeur(s) : HAL CCSD
Résumé : International audience
This paper deals with variational inclusions of the form 0 ∈ K − f(x) − g(x) where f is a smooth function from a reflexive Banach space X into a Banach space Y , g is a function from X into Y admitting divided differences and K is a nonempty closed convex cone in the space Y . We show that the previous problem can be solved by a combination of two methods: the Newton and the Secant methods. We show that the order of the semilocal method obtained is equal to (1 + √5)/2. Numerical results are also given to illustrate the convergence at the end of the paper.
Serdica Math. J.

hal-00924150
https://hal.archives-ouvertes.fr/hal-00924150

Résumé : L'objectif du registre des cancers de Guyane est de collecter l ensemble des tumeurs invasives et/ou in situ survenues depuis le 1er janvier 2003 chez des patients vivant en Guyane, quels que soient la localisation de la tumeur, le lieu de diagnostic et de traitement. Cette thèse a pour but de décrire la population atteinte d un cancer afin d améliorer les connaissances sur cette maladie et ainsi de permettre aux actions de santé publique d être plus efficaces.De 2003 à 2009, le taux d incidence des cancers standardisé sur l âge était, dans les deux sexes, 30% inférieur en Guyane par rapport à la France métropolitaine et n était pas différent de celui d Amérique du Sud.Nous avons comparé l incidence, la mortalité et la survie relative des patientes atteintes d un cancer invasif du sein (CIS) et des patientes atteintes d un cancer invasif du col de l utérus (CIC) entre la Guyane et la métropole.Le ratio incidence/mortalité indiquait que les cancers du sein étaient de plus mauvais pronostic en Guyane par rapport à la métropole.La survie relative des femmes atteintes d un CIS était inférieure en Guyane par rapport à la France métropolitaine.En Guyane, le taux standardisé d incidence du cancer du col de l utérus était 4 fois plus élevé qu en métropole. Les femmes vivant dans l intérieur de la Guyane semblaient être diagnostiquées à un stade plus tardif et plus souvent sur symptômes que les femmes du littoral. L accès aux soins des migrants est un challenge et une source d inégalité de santé. La détection précoce des cancers à travers des programmes de prévention est cruciale pour améliorer la survie par cancer et notamment chez les patients étrangers.
The objective of the cancer registry of French Guiana is to compile all patients living in French Guiana with malignant invasive pathology and/or in situ lesions starting January 1st 2003 in persons living in French Guiana, whatever the tumoral location and the place of diagnosis and care. This study aimed to describe the population with invasive cancer to improve the knowledge about this disease in order to target public health interventions more effectively.The age standardised incidence rate was 30% times lower than in France in both sexes and the same than in South America.We compared incidence and relative survival of patients with invasive breast cancer (IBC) and patients with invasive cervical cancer (ICC) between women from French Guiana and metropolitan France.The ratio between incidence and mortality showed that the prognosis of IBC in French Guiana was worse than in metropolitan France.The relative survival rate among women with IBC in French Guiana was lower than among women in metropolitan France.In French Guiana, the age-standardized incidence rate of cervical cancer was four times higher than in France. Women living in remote areas seemed to be diagnosed later and more often following symptoms.Access to care for migrants is challenging and sustains health inequalities. Early detection through prevention programs is crucial for increasing cancer survival notably for foreign-born patients. Further studies with more patients and other variables could improve the knowledge about these diseases

http://www.theses.fr/2014AGUY0743/document

Éditeur(s) : World Aquaculture Society, Aquaculture 2006
Résumé : Oysters are among the most familiar of all marine invertebrate taxa. However our knowledge of oyster phylogeny and systematics is fragmentary. This is principally due to the plastic growth patterns of these animals, which result in a wide range of overlapping, ecophenotypic variants that greatly reduce the value of analysis based on shell morphology. Besides that, many intentional or accidental anthropogenic transfers have emphasised this situation. In several cases of misclassification or misidentification of oysters, DNA molecular data, have provided valuable new insights on the tracing of introductions or more generally on the phylogeographic relationships between oyster species. We will illustrate this issue with recent case studies from our lab on several flat and cupped oysters: (1) the Crassostrea gigas – Crassostrea angulata couple of Asian species and their successive introductions in Europe, (2) the new species of cupped oysters, Crassostrea honkongensis, described in Hong-Kong and very divergent from the species Crassostrea gigas it was initially supposed to be, (3) the mangrove oyster Crassostrea gasar that was shown not only to be present along the coasts of Western Africa but also along the Atlantic coasts of South America, and (4) the geographic disjunction between Ostreola stentina, described in the Mediterranean Sea, and the genetically closely related species Ostrea aupouria (from New Zealand) and Ostreola equestris (from Mexico Gulf/Atlantic). At the intra specific level, we will focus on one of the main documented case in Europe, the flat oyster, Ostrea edulis. It is a marine bivalve whose natural geographical distribution ranges along the European Atlantic coast from Norway to Morocco, in addition to the Mediterranean and Black Sea. Studies of allozymes, microsatellites and mitochondrial differentiation over the whole range concluded that a significant divergence existed between Mediterranean and Atlantic populations, together with an isolation-by-distance pattern. However, the average mitochondrial haplotypic diversity displayed a high among populations variance, reflecting smaller effective population size in some locations. Additionally, a ten-fold quantitative difference was observed in the same study in Fst between the mitochondrial and the nuclear genomes, which could be due to sex biased differential reproductive success between males and females. In order to further document this hypothesis, two experiments at the population level were conducted. First, brooding females were sampled in a wild population and the number of males fertilizing a given female estimated. Then, parentage analyses were achieved under experimental conditions: successive mass spawnings were collected from a population of potential genitors kept in hatchery, whose genotypes were known, in order to infer a posteriori the relative contribution of each genitor. Moreover, we aimed to better understand the reproduction dynamics of this species. Several patterns of spawning could be distinguished: unique, successive or extended in time. The different parental contributions and reproductive behaviors observed in these experiments are discussed in the context of the hypothesis of a variance in the reproductive success of males and females and consequences in local and temporal reduced effective population sizes.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/acte-3475.pdf
http://archimer.ifremer.fr/doc/00000/3475/

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Deciphering the evolutionary processes driving nucleotide variation in multiallelic genes is limited by the number of genetic systems in which such genes occur. The complementary sex determiner (csd) gene in the honey bee Apis mellifera is an informative example for studying allelic diversity and the underlying evolutionary forces in a well-described model of balancing selection. Acting as the primary signal of sex determination, diploid individuals heterozygous for csd develop into females, whereas csd homozygotes are diploid males that have zero fitness. Examining 77 of the functional heterozygous csd allele pairs, we established a combinatorical criteria that provide insights into the minimum number of amino acid differences among those pairs. Given a data set of 244 csd sequences, we show that the total number of csd alleles found in A. mellifera ranges from 53 (locally) to 87 (worldwide), which is much higher than was previously reported (20). Using a coupon-collector model, we extrapolate the presence of in total 116-145 csd alleles worldwide. The hypervariable region (HVR) is of particular importance in determining csd allele specificity, and we provide for this region evidence of high evolutionary rate for length differences exceeding those of microsatellites. The proportion of amino acids driven by positive selection and the rate of nonsynonymous substitutions in the HVR-flanking regions reach values close to 1 but differ with respect to the HVR length. Using a model of csd coalescence, we identified the high originating rate of csd specificities as a major evolutionary force, leading to an origin of a novel csd allele every 400,000 years. The csd polymorphism frequencies in natural populations indicate an excess of new mutations, whereas signs of ancestral transspecies polymorphism can still be detected. This study provides a comprehensive view of the enormous diversity and the evolutionary forces shaping a multiallelic gene.
ISSN: 0737-4038

hal-01544758
https://hal.archives-ouvertes.fr/hal-01544758
DOI : 10.1093/molbev/mst207

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The last step of oestrogen biosynthesis is catalyzed by the enzyme aromatase, the product of the cyp19a1 gene. In vertebrates, cyp19a1 is expressed in the brain resulting in a local oestrogen production that seems important not only for the control of reproduction-related circuits and sexual behaviour, but also for the regulation of neural development, synaptic plasticity and cell survival. In adult amphibians, the precise sites of expression of cyp19a1 in the brain have not been investigated which prevents proper understanding of its potential physiological functions. The present study aimed at examining the precise neuroanatomical distribution of cyp19a1 transcripts in adult brains of both male and female Xenopus. We found that cyp19a1 expression is highly regionalized in the brains of both sexes. The highest expression was found in the anterior part of the preoptic area and in the caudal hypothalamus, but significant levels of cyp19a1 transcripts were also found in the supraoptic paraventricular and suprachiasmatic areas, and in brain regions corresponding to the septum, bed nucleus of the stria terminalis and amygdala. Importantly, no obvious difference between male and female Xenopus was detected at the level of cyp19a1 transcripts. Additionally, in the brain of adult Xenopus, cyp19a1 transcripts were detected in neurons, and not in glial cells. These data and those available in other vertebrates on cyp19a1/aromatase expression suggest that, with the intriguing exception of teleost fishes, cyp19a1 was under strong evolutionary conservation with respect to its sites of expression and the nature of the cells in which it is expressed
ISSN: 0016-6480

hal-01187140
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187140
DOI : 10.1016/j.ygcen.2015.08.008
PUBMED : 26255686

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Growth charts are an essential clinical tool for evaluating a child's health and development. The current French reference curves, published in 1979, have recently been challenged by the 2006 World Health Organization (WHO) growth charts. To evaluate and compare the growth of French children who were born between 1981 and 2007, with the WHO growth charts and the French reference curves currently used. Anthropometric measurements from French children, who participated in 12 studies, were analyzed: 82,151 measurements were available for 27,257 children in different age groups, from birth to 18 years. We calculated and graphically compared mean z-scores based on the WHO and French curves, for height, weight and Body Mass Index (BMI) according to age and sex. The prevalence of overweight using the WHO, the French and International Obesity Task Force definitions were compared. Our population of children was on average 0.5 standard deviations taller than the French reference population, from the first month of life until puberty age. Mean z-scores for height, weight and BMI were closer to zero based on the WHO growth charts than on the French references from infancy until late adolescence, except during the first six months. These differences not related to breastfeeding rates. As expected, the prevalence of overweight depended on the reference used, and differences varied according to age. The WHO growth charts may be appropriate for monitoring growth of French children, as the growth patterns in our large population of French children were closer to the WHO growth charts than to the French reference curves, from 6 months onwards. However, there were some limitations in the use of these WHO growth charts, and further investigation is needed.
ISSN: 1932-6203

hal-01134193
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134193
DOI : 10.1371/journal.pone.0120806
PUBMED : 25761138
PUBMEDCENTRAL : PMC4356547

Éditeur(s) : HAL CCSD BioScientifica
Résumé : International audience
BACKGROUND: Differences in circulating steroid hormone levels have been hypothesized to explain ethnic differences in steroid-related diseases. The aim of this study was to determine the serum levels of a wide panel of steroid hormones, both androgens and estrogens, in healthy middle-aged African-Caribbean and European men. DESIGN AND METHODS: Serum steroid hormone levels were determined in men participating in a systematic public health study funded by the French National Health Insurance system. Blood was collected in the morning from 304 healthy African-Caribbean and European men aged between 40 and 69 years. Serum steroids were measured by mass spectrometry-gas chromatography, except for DHEAS and sex hormone-binding globulin, which were determined by RIA. Data were analyzed in 10-year age intervals by analysis of covariance, with adjustment for age, body mass index, waist-to-hip ratio, tobacco and alcohol consumption, and season of sampling. RESULTS: Compared with Europeans, African-Caribbean men presented significantly higher serum levels of measured bioavailable testosterone, 4-androstenedione (4-dione), and estrone (E1) regardless of the age group, of 5-androstenediol (5-diol) in those aged 40-49 and 50-59 years, and of testosterone (TT) and dihydrotestosterone in those aged 40-49 years. In contrast, European men aged 40-69 years showed significantly higher serum levels of DHEA and DHEAS. CONCLUSIONS: Significant differences in serum steroid hormone levels were observed in middle-aged African-Caribbean and European men. Whether such differences could contribute to ethnic differences in disease risk in adult men remains to be investigated. Some steroids, such as bioavailable TT, 4-dione, 5-diol, and E1, deserve particular attention.
ISSN: 0804-4643

hal-00876034
https://hal.archives-ouvertes.fr/hal-00876034
DOI : 10.1530/EJE-11-0551
PUBMED : 21951700