Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
This article documents several cases of widespread species, which usually mimic other widespread species throughout the Indo–Pacific, using endemic Marquesan species as a model and displaying endemic mimicry patterns. This discovery adds a new line of evidence to the uniqueness of the Marquesas Islands, which not only host a high number of endemic reef–fish species, but also endemic mimicry patterns.
ISSN: 0022-1112

hal-01338324
http://hal.upmc.fr/hal-01338324
http://hal.upmc.fr/hal-01338324/document
http://hal.upmc.fr/hal-01338324/file/2016_Delrieu%E2%80%90Trottin%20et%20al_When%20endemic.pdf
DOI : 10.1111/jfb.13050

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The emerging orbicular batfish (Platax orbicularis) aquaculture is the most important fish aquacultureindustry in French Polynesia. However, bacterial infections are causing severe mortality episodes.Therefore, there is an urgent need to find an effective management solution. Besides the supplyingdifficulty and high costs of veterinary drugs in French Polynesia, batfish aquaculture takes place close tothe coral reef, where use of synthetic persistent drugs should be restricted. Medicinal plants andbioactive algae are emerging as a cheaper and more sustainable alternative to chemical drugs. We havestudied the effect of local Polynesian plants and the local opportunistic algae Asparagopsis taxiformis onbatfish when orally administered. Weight gain and expression of two immune-related genes (lysozyme ge Lys G and transforming growth factor beta - TGF-b1) were studied to analyze immunostimulant activityof plants on P. orbicularis. Results showed that several plants increased Lys G and TGF-b1 expressionon orbicular batfish after 2 and 3 weeks of oral administration. A. taxiformis was the plant displaying themost promising results, promoting a weight gain of 24% after 3 weeks of oral administration andsignificantly increasing the relative amount of both Lys G and TGF-b1 transcripts in kidney and spleen ofP. orbicularis.
ISSN: 1050-4648

hal-01381334
https://hal-univ-perp.archives-ouvertes.fr/hal-01381334
DOI : 10.1016/j.fsi.2016.09.011

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The hypothalamic-pituitary-adrenal (HPA) axis response to chronic stress is far from straight forward, particularly with regards to animal welfare. There are reports of no effect as well as both decreases and increases in cortisol after chronic stressors. Therefore, the first aim of the present study was to determine how measures of compromised welfare, such as chronic pain and haematological anomalies, related to cortisol levels in domestic horses (Equus caballus). Domestic horses are an informative model to investigate the impact of chronic stress (due to environment, pain, work, housing conditions…) on the HPA axis. The second aim was to determine whether levels of fecal cortisol metabolites (FCM) may be used as an indicator of welfare measures. The present study used fifty-nine horses (44 geldings and 15 mares), from three riding centres in Brittany, France. The primary findings show that horses whose welfare was clearly compromised (as indicated by an unusual ears backward position, presence of vertebral problems or haematological anomalies, e.g. anaemia) also had lower levels of both FCM and plasma cortisol. This work extends our previous findings showing that withdrawn postures, indicators of depressive-like behavior in horses, are associated with lower plasma cortisol levels. We also found that evening plasma cortisol levels positively correlated with FCM levels in horses. Future research aims to determine the extent to which factors of influence on welfare, such as living conditions (e.g. single stalls versus group housing in pasture or paddocks), early life factors, and human interaction, act as mediators of cortisol levels in horses.
ISSN: 1932-6203

hal-01588159
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01588159
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01588159/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01588159/file/Pawluski_et_al_-_PLOSONE-2017.pdf
DOI : 10.1371/journal.pone.0182257

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Ghrelin is a gut-brain peptide hormone, which binds to the growth hormone secretagogue receptor (GHS-R) to regulate a wide variety of biological processes in fish. Despite these prominent physiological roles, no studies have reported the anatomical distribution of preproghrelin transcripts using in situ hybridization in a non-mammalian vertebrate, and its mapping within the different encephalic areas remains unknown. Similarly, no information is available on the possible 24-h variations in the expression of preproghrelin and its receptor in any vertebrate species. The first aim of this study was to investigate the anatomical distribution of ghrelin and GHS-R1a ghrelin receptor subtype in brain and gastrointestinal tract of goldfish (Carassius auratus) using immunohistochemistry and in situ hybridization. Our second aim was to characterize possible daily variations of preproghrelin and ghs-r1 mRNA expression in central and peripheral tissues using real-time reverse transcription-quantitative PCR. Results show ghrelin expression and immunoreactivity in the gastrointestinal tract, with the most abundant signal observed in the mucosal epithelium. These are in agreement with previous findings on mucosal cells as the primary synthesizing site of ghrelin in goldfish. Ghrelin receptor was observed mainly in the hypothalamus with low expression in telencephalon, pineal and cerebellum, and in the same gastrointestinal areas as ghrelin. Daily rhythms in mRNA expression were found for preproghrelin and ghs-r1 in hypothalamus and pituitary with the acrophase occurring at nighttime. Preproghrelin, but not ghs-r1a, displayed a similar daily expression rhythm in the gastrointestinal tract with an amplitude 3-fold higher than the rest of tissues. Together, these results described for the first time in fish the mapping of preproghrelin and ghrelin receptor ghs-r1a in brain and gastrointestinal tract of goldfish, and provide the first evidence for a daily regulation of both genes expression in such locations, suggesting a possible connection between the ghrelinergic and circadian systems in teleosts
ISSN: 1932-6203

hal-01225511
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01225511
DOI : 10.1371/journal.pone.0141043
PUBMED : 26506093

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
In contrast to mammals that have limited proliferation and neurogenesis capacities, the Xenopus frog exhibit a great potential regarding proliferation and production of new cells in the adult brain. This ability makes Xenopus a useful model for understanding the molecular programs required for adult neurogenesis. Transcriptional factors that control adult neurogenesis in vertebrate species undergoing widespread neurogenesis are unknown. NeuroD1 is a member of the family of proneural genes, which function during embryonic neurogenesis as a potent neuronal differentiation factor. Here, we study in detail the expression of NeuroD1 gene in the juvenile and adult Xenopus brains by in situ hybridization combined with immunodetections for proliferation markers (PCNA, BrdU) or in situ hybridizations for cell type markers (Vimentin, Sox2). We found NeuroD1 gene activity in many brain regions, including olfactory bulbs, pallial regions of cerebral hemispheres, preoptic area, habenula, hypothalamus, cerebellum and medulla oblongata. We also demonstrated by double staining NeuroD1/BrdU experiments, after long post-BrdU administration survival times, that NeuroD1 gene activity was turned on in new born neurons during post-metamorphic neurogenesis. Importantly, we provided evidence that NeuroD1-expressing cells at this brain developmental stage were post-mitotic (PCNA-) cells and not radial glial (Vimentin+) or progenitors (Sox2+) cells.
ISSN: 1932-6203

hal-00877023
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00877023
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00877023/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00877023/file/The_Neurogenic_Factor-accepted.pdf
DOI : 10.1371/journal.pone.0066487

Éditeur(s) : HAL CCSD American Physiological Society
Résumé : Full text: http://jn.physiology.org/content/88/3/1475
International audience
The contribution of voltage-gated calcium channels (VGCC) to the development of cultured embryonic cockroach brain neurons was assessed using pharmacological agents. VGCC currents were recorded using the patch-clamp technique and were found to be blocked dose-dependently by micromolar concentrations of mibefradil. The activation and inactivation properties of the calcium channels enable a sizeable calcium current to flow at rest (about -30 and -20 mV in high-potassium culture media). As expected, the cytoplasmic-free calcium concentration was found to rise when the extracellular potassium concentration was raised from 3 to 15 and 30 mM. The effects of VGCC blockers and calcium chelators were different in fresh and in mature cultures in which the neurons were connected to each other to form a defined network. In fresh cultures, the two non-selective VGCC blockers (verapamil and mibefradil) induced a dose-dependent cell death that was proportional to their blocking effect on I(Ba). This effect could not be prevented by addition of fetal calf serum to the culture medium. A similar effect was obtained using intra- or extracellular calcium chelating agents (10 microM BAPTA-AM or 10 mM EGTA). Quite unexpectedly, blockade of the P/Q-like (omega-Aga WA-sensitive) component of the calcium current by 500 nM of omega-AgaTx IVA had no lethal effect, suggesting that the corresponding channels are not involved in the survival mechanism. As expected from their lack of effect on I(Ba), isradipine, nifedipine, and omega-CgTx GVIA did not induce cell death. When the neurons started growing neurites, their sensitivity to calcium channel blockade by mibefradil decreased, indicating a correlation between neurite outgrowth and resistance to calcium depletion. In mature cultures, the neurons became resistant to mibefradil, verapamil, and BAPTA-AM. However, these agents, as well as omega-AgaTx IVA, had a significant inhibitory effect on the increase in diameter of the connectives that linked adjacent clusters of neurons. This effect has been shown to result, in the case of mibefradil, from an inhibition of neurite outgrowth characterized by a significant reduction of the number of primary neurites and secondary branchings but not to a significant modification of the diameter of individual neurites. These results support the view that, as in vertebrates, calcium influx through VGCC plays an important role in survival and neurite outgrowth of cultured embryonic insect neurons. The differential contribution of the P/Q-like and R-like (omega-Aga WA-sensitive) calcium channels in these processes is discussed.
ISSN: 0022-3077

hal-00982287
https://hal.archives-ouvertes.fr/hal-00982287
DOI : 10.1152/jn.00749.2001
PUBMED : 12205168

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
The cyp19a1 gene that encodes aromatase, the only enzyme permitting conversion of C19 aromatizable androgens into estrogens, is present as a single copy in the genome of most vertebrate species, except in teleosts in which it has been duplicated. This study aimed at investigating the brain expression of a cyp19a1 gene expressed in both gonad and brain of Japanese eel, a basal teleost. By means of immunohistochemistry and in situ hybridization, we show that cyp19a1 is expressed only in radial glial cells of the brain and in pituitary cells. Treatments with salmon pituitary homogenates (female) or human chorionic gonadotrophin (male), known to turn on steroid production in immature eels, strongly stimulated cyp19a1 messenger and protein expression in radial glial cells and pituitary cells. Using double staining studies, we also showed that aromatase-expressing radial glial cells exhibit proliferative activity in both the brain and the pituitary. Altogether, these data indicate that brain and pituitary expression of Japanese eel cyp19a1 exhibits characteristics similar to those reported for the brain specific cyp19a1b gene in teleosts having duplicated cyp19a1 genes. This supports the hypothesis that, despite the fact that eels also underwent the teleost specific genome duplication, they have a single cyp19a1 expressed in both brain and gonad. Such data also suggest that the intriguing features of brain aromatase expression in teleost fishes were not gained after the whole genome duplication and may reflect properties of the cyp19a1 gene of ancestral Actinopterygians.
ISSN: 1932-6203

hal-00877375
https://hal.archives-ouvertes.fr/hal-00877375
https://hal.archives-ouvertes.fr/hal-00877375/document
https://hal.archives-ouvertes.fr/hal-00877375/file/Expressionsur Aromatase-accepted.pdf
DOI : 10.1371/journal.pone.0044750

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
To analyze the characteristics and outcome of infective endocarditis (IE) according to the time interval between IE first symptoms and diagnosis.
Among the IE cases of a French population-based epidemiological survey, patients having early-diagnosed IE (diagnosis of IE within 1 month of first symptoms) were compared with those having late-diagnosed IE (diagnosis of IE more than 1 month after first symptoms).
Among the 486 definite-IE, 124 (25%) had late-diagnosed IE whereas others had early-diagnosed IE. Early-diagnosed IE were independently associated with female gender (OR = 1.8; 95% CI [1.0-3.0]), prosthetic valve (OR= 2.6; 95% CI [1.4-5.0]) and staphylococci as causative pathogen (OR = 3.7; 95% CI [2.2-6.2]). Cardiac surgery theoretical indication rates were not different between early and late-diagnosed IE (56.3% vs 58.9%), whereas valve surgery performance was lower in early-diagnosed IE (41% vs 53%; p = .03). In-hospital mortality rates were higher in early-diagnosed IE than in late-diagnosed IE (25.1% vs 16.1%; p < .001).
The time interval between IE first symptoms and diagnosis is closely related to the IE clinical presentation, patient characteristics and causative microorganism. Better prognosis reported in late-diagnosed IE may be related to a higher rate of valvular surgery. KEY MESSAGES Infective endocarditis, which time interval between first symptoms and diagnosis was less than one month, were mainly due to Staphylococcus aureus in France. Staphylococcus aureus infective endocarditis were associated with septic shock, transient ischemic attack or stroke and higher mortality rates than infective endocarditis due to other bacteria or infective endocarditis, which time interval between first symptoms and diagnosis was more than one month. Infective endocarditis, which time interval between first symptoms and diagnosis was more than one month, were accounting for one quarter of all infective endocarditis in our study and were associated with vertebral osteomyelitis and a higher rate of cardiac surgery performed for hemodynamic indication than other infective endocarditis.
ISSN: 0785-3890

hal-01509563
https://hal.archives-ouvertes.fr/hal-01509563
PUBMED : 27607562

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: Ameloblastin (AMBN) is a phosphorylated, proline/glutamine-rich protein secreted during enamel formation. Previous studies have revealed that this enamel matrix protein was present early in vertebrate evolution and certainly plays important roles during enamel formation although its precise functions remain unclear. We performed evolutionary analyses of AMBN in order to (i) identify residues and motifs important for the protein function, (ii) predict mutations responsible for genetic diseases, and (iii) understand its molecular evolution in mammals. Results: In silico searches retrieved 56 complete sequences in public databases that were aligned and analyzed computationally. We showed that AMBN is globally evolving under moderate purifying selection in mammals and contains a strong phylogenetic signal. In addition, our analyses revealed codons evolving under significant positive selection. Evidence for positive selection acting on AMBN was observed in catarrhine primates and the aye-aye. We also found that (i) an additional translation initiation site was recruited in the ancestral placental AMBN, (ii) a short exon was duplicated several times in various species including catarrhine primates, and (iii) several polyadenylation sites are present. Conclusions: AMBN possesses many positions, which have been subjected to strong selective pressure for 200 million years. These positions correspond to several cleavage sites and hydroxylated, O-glycosylated, and phosphorylated residues. We predict that these conserved positions would be potentially responsible for enamel disorder if substituted. Some motifs that were previously identified as potentially important functionally were confirmed, and we found two, highly conserved, new motifs, the function of which should be tested in the near future. This study illustrates the power of evolutionary analyses for characterizing the functional constraints acting on proteins with yet uncharacterized structure.
ISSN: 1471-2148

Droits : http://creativecommons.org/licenses/by/
hal-01212816
http://hal.upmc.fr/hal-01212816
http://hal.upmc.fr/hal-01212816/document
http://hal.upmc.fr/hal-01212816/file/s12862-015-0431-0.pdf
DOI : 10.1186/s12862-015-0431-0

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
: In non-mammalian vertebrates, serotonin (5-HT)-producing neurons exist in the paraventricular organ (PVO), a diencephalic structure containing cerebrospinal fluid (CSF)-contacting neurons exhibiting 5-HT or dopamine (DA) immunoreactivity. Because the brain of the adult teleost is known for its neurogenic activity supported, for a large part, by radial glial progenitors, this study addresses the origin of newborn 5-HT neurons in the hypothalamus of adult zebrafish. In this species, the PVO exhibits numerous radial glial cells (RGCs) whose somata are located at a certain distance from the ventricle. To study relationships between RGCs and 5-HT CSF-contacting neurons, we performed 5-HT immunohistochemistry in transgenic tg(cyp19a1b-GFP) zebrafish in which RGCs are labelled with GFP under the control of the cyp19a1b promoter. We show that the somata of the 5-HT neurons are located closer to the ventricle than those of RGCs. RGCs extend towards the ventricle cytoplasmic processes that form a continuous barrier along the ventricular surface. In turn, 5-HT neurons contact the CSF via processes that cross this barrier through small pores. Further experiments using proliferating cell nuclear antigen or 5-bromo-2'-deoxyuridine indicate that RGCs proliferate and give birth to 5-HT neurons migrating centripetally instead of centrifugally as in other brain regions. Furthermore, treatment of adult zebrafish with tryptophan hydroxylase inhibitor causes a significant decrease in the number of proliferating cells in the PVO, but not in the mediobasal hypothalamus. These data point to the PVO as an intriguing region in which 5-HT appears to promote genesis of 5-HT neurons that accumulate along the brain ventricles and contact the CSF.
ISSN: 0953-816X

inserm-00866212
http://www.hal.inserm.fr/inserm-00866212
DOI : 10.1111/ejn.12348
PUBMED : 23981075

Éditeur(s) : Elsevier
Résumé : Marine fish larvae undergo major morphological and cellular changes during the first month of life. The ontogeny of the gastrointestinal tract combines these two aspects of the larval development and is very interesting in that the timing of functional changes appears genetically hard-wired. The goal of this paper is to give an overview of the gastrointestinal development process in marine fish larvae, with particular attention to three species: sea bass; red drum; and sole, since the description of gut maturation in fish larvae was initiated during the last decade with these species. During the early stages, marine fish larvae exhibit particular digestive features. Concerning the exocrine pancreas, amylase expression decreases with age from the third week post-hatching in sea bass and red drum (approximately 400 degree days), whereas expression of other enzymes (trypsin, lipase, phospholipase A2...) increases until the end of the larva period. Moreover, secretory function of the exocrine pancreas progressively develops and becomes efficient after the third week of life. Concerning the intestine, enzymes of the enterocyte cytosol (in particular peptidase) have higher activity in young larvae than in older. Approximately in the fourth week of post-hatching development in sea bass, red drum and sole larvae, the cytosolic activities dramatically decline concurrently with a sharp increase in membranous enzyme activities of the brush border, such as alkaline phosphatase, aminopeptidase N, maltase... This process characterises the normal maturation of enterocytes in developing fish larvae and also in other vertebrates' species. The establishment of an efficient brush border membrane digestion represents the adult mode of digestion of enterocytes. This paper also describes the role of diet on the development of the gastrointestinal tract. Indeed, the maturational process of digestive enzyme can be enhanced, stopped, or delayed depending on the composition of the diet.
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology (1532-0456) (Elsevier), 2001-12 , Vol. 130 , N. 4 , P. 477-487

Droits : 2001 Elsevier Science Inc. All rights reserved
http://archimer.ifremer.fr/doc/2001/publication-650.pdf
DOI:10.1016/S1532-0456(01)00274-5
http://archimer.ifremer.fr/doc/00000/650/

Éditeur(s) : HAL CCSD American Society for Biochemistry and Molecular Biology
Résumé : International audience
alpha- and beta-spectrins are components of molecular scaffolds located under the lipid bilayer and named membrane skeletons. Disruption of these scaffolds through mutations in spectrins demonstrated that they are involved in the membrane localization or the maintenance of proteins associated with them. The ubiquitous alphaII-spectrin chain bears in its central region a unique domain that is sensitive to several proteases such as calpains or caspases. The conservation of this region in vertebrates suggests that the proteolysis of alphaII-spectrin by these enzymes could be involved in important functions. To assess the role of alphaII-spectrin cleavage in vivo, we generated a murine model in which the exons encoding the region defining this cleavage sensitivity were disrupted by gene targeting. Surprisingly, homozygous mice expressing this mutant alphaII-spectrin appeared healthy, bred normally, and had no histological anomaly. Remarkably, the mutant alphaII-spectrin assembles correctly into the membrane skeleton, thus challenging the notion that this region is required for the stable biogenesis of the membrane skeleton in nonerythroid cells. Our finding also argues against a critical role of this particular alphaII-spectrin cleavage in either major cellular functions or in normal development.
ISSN: 0021-9258

inserm-00284621
http://www.hal.inserm.fr/inserm-00284621
http://www.hal.inserm.fr/inserm-00284621/document
http://www.hal.inserm.fr/inserm-00284621/file/Meary_-_JBC_2007.pdf
PUBMED : 17374614

Éditeur(s) : Academic Press Ltd- Elsevier Science Ltd
Résumé : Over the last decade, RNA interference pathways have emerged in eukaryotes as critical regulators of many diverse biological functions including, among others, transcriptional gene regulation, post-transcriptional gene silencing, heterochromatin remodelling, suppression of transposon activity, and antiviral defences. Although this gene silencing process has been reported to be relatively well conserved in species of different phyla, there are important discrepancies between plants, invertebrates and mammals. In penaeid shrimp, the existence of an intact and functional RNAi machinery is supported by a rapidly growing body of evidence. However, the extent to which this process participates to the host immune responses remains poorly defined in this non-model organism. This review summarizes our current knowledge of RNAi mechanisms in shrimp and focuses on their implication in antiviral activities and shrimp immune defences.
Fish & Shellfish Immunology (1050-4648) (Academic Press Ltd- Elsevier Science Ltd), 2013-04 , Vol. 34 , N. 4 , P. 1002-1010

Droits : 2012 Elsevier Ltd. Published by Elsevier Ltd
http://archimer.ifremer.fr/doc/00119/23063/20899.pdf
DOI:10.1016/j.fsi.2012.06.008
http://archimer.ifremer.fr/doc/00119/23063/

Éditeur(s) : Centre Océanologique de Bretagne
Résumé : Après une période de croissance rapide depuis la seconde guerre mondiale, l'exploitation des ressources vivantes des océans est stabilisée depuis quelques années entre 60 et 65 millions de tonnes par an, pour l'ensemble des océans. Ces chiffres recouvrent l'ensemble des produits tirés de la mer, qu'il s'agisse de vertébrés ou d'invertébrés, d'animaux ou de végétaux. De même, la distinction entre produit de la pêche et produit de la culture ou de l'élevage n'est pas faite. En réalité, si les poissons représentent une partie importante de ce total, l'homme exploite également la plupart des groupes zoologiques d'invertébrés marins, quelques reptiles et les mammifères marins (cétacés et pinnipèdes), et des algues (en particulier des algues rouges et des algues brunes). Dans la plupart des cas, ces groupes sont exploités en vue de l'alimentation humaine ; il existe toutefois d'autres formes d'utilisation de certaines espèces, l'une des plus connues étant l'utilisation des algues pour la production d'alginates, de carragen et d'agar-agar. L'utilisation de certaines espèces de gastéropodes marins pour la fabrication de colorants remonte en Méditerranée a l'époque antique (la pourpre). L'utilisation de coquillages à des fins décoratives ou même en tant que monnaie d'échange a été très répandue chez les populations des îles du Pacifique ; la collection de l'amateur moderne, comportant des pièces atteignant une valeur élevée, peut être considérée comme un dérivé récent de ces usages traditionnels. Afin de ne pas alourdir l'exposé, nous limiterons volontairement cet inventaire aux algues et aux invertébrés, utilisés dans l'alimentation humaine, à l'exclusion des autres formes d'utilisation (1). [OCR NON CONTRÔLE]
Recueil des travaux du Centre Océanologique de Bretagne (Centre Océanologique de Bretagne), 1971 , N. 5 , P. 527-537

Droits : Centre Océanologique de Bretagne
http://archimer.ifremer.fr/doc/1971/publication-5110.pdf
http://archimer.ifremer.fr/doc/00000/5110/

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Fish mucus has important biological and ecologicalroles such as defense against fish pathogens andchemical mediation among several species. A non-targetedliquid chromatography–mass spectrometry metabolomicapproach was developed to study gill mucus of eight butterflyfishspecies in Moorea (French Polynesia), and theinfluence of several fish traits (geographic site and reefhabitat, species taxonomy, phylogeny, diet and parasitismlevels) on the metabolic variability was investigated. Abiphasic extraction yielding two fractions (polar and apolar)was used. Fish diet (obligate corallivorous, facultativecorallivorous or omnivorous) arose as the main driver ofthe metabolic differences in the gill mucus in both fractions,accounting for 23% of the observed metabolic variabilityin the apolar fraction and 13% in the polar fraction.A partial least squares discriminant analysis allowed us toidentify the metabolites (variable important in projection,VIP) driving the differences between fish with differentdiets (obligate corallivores, facultative corallivores andomnivorous). Using accurate mass data and fragmentationdata, we identified some of these VIP as glycerophosphocholines,ceramides and fatty acids. Level of monogeneangill parasites was the second most important factor shapingthe gill mucus metabolome, and it explained 10% of themetabolic variability in the polar fraction and 5% in theapolar fraction. A multiple regression tree revealed that themetabolic variability due to parasitism in the polar fractionwas mainly due to differences between non-parasitized andparasitized fish. Phylogeny and butterflyfish species werefactors contributing significantly to the metabolic variabilityof the apolar fraction (10 and 3%, respectively) buthad a less pronounced effect in the polar fraction. Finally,geographic site and reef habitat of butterflyfish species didnot influence the gill mucus metabolome of butterflyfishes.
ISSN: 0722-4028

hal-01563312
https://hal-univ-perp.archives-ouvertes.fr/hal-01563312
DOI : 10.1007/s00338-017-1554-0

Éditeur(s) : HAL CCSD Linnean Society of London
Résumé : Disentangling the impact of landscape features such as rivers and historical events on dispersal is a challenging but necessary task to gain a comprehensive picture of the evolution of diverse biota such as that found in Amazonia. Adenomera andreae, a small, territorial, terrestrial frog species of the Amazonian forest represents a good model for such studies. We combined cytochrome b sequences with 12 microsatellites to investigate the genetic structure at two contrasted spatial scales in French Guiana: along a similar to 6-km transect, to evaluate dispersal ability, and between paired bank populations along a similar to 65-km stretch of the Approuague river, to test the effect of rivers as barriers to dispersal. We observed significant spatial genetic structure between individuals at a remarkably small geographical scale, and conclude that the species has a restricted dispersal ability that is probably tied to its life-history traits. Mitochondrial and microsatellite data also indicate a high level of differentiation among populations on opposite banks of the river, and, in some cases, among populations on the same riverbank. These results suggest that the observed population structure in A. andreae is the result of restricted dispersal abilities combined with the action of rivers and Quaternary population isolation. Given that Amazonia hosts a great portion of anurans, as well as other small vertebrates, that display life-history traits comparable with A. andreae, we argue that our analyses provide new insights into the complex interactions among evolutionary processes shaping Amazonian biodiversity. (c) 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 356373.
ISSN: 0024-4066

hal-01032422
https://hal.archives-ouvertes.fr/hal-01032422
DOI : 10.1111/j.1095-8312.2012.01871.x

Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : International audience
Whereas broad-scale Amazonian forest types have been shown to influence the structure of the communities of medium-to large-bodied vertebrates, their natural heterogeneity at smaller scale or within the terra firme forests remains poorly described and understood. Diversity indices of such communities and the relative abundance of the 21 most commonly observed species were compared from standardized line-transect data across 25 study sites distributed in undisturbed forests in French Guiana. We first assessed the relevance of a forest typology based on geomorphological landscapes to explain the observed heterogeneity. As previously found for tree beta-diversity patterns, this new typology proved to be a non-negligible factor underlying the beta diversity of the communities of medium-to large bodied vertebrates in French Guianan terra firme forests. Although the species studied are almost ubiquitous across the region, they exhibited habitat preferences through significant variation in abundance and in their association index with the different landscape types. As terra firme forests represent more than 90% of the Amazon basin, characterizing their heterogeneity-including faunal communities-is a major challenge in neotropical forest ecology.
ISSN: 0266-4674

hal-01502647
https://hal-agroparistech.archives-ouvertes.fr/hal-01502647
DOI : 10.1017/S0266467415000255

Éditeur(s) : HAL CCSD
Résumé : The trophic endosymbiosis interaction between a cnidarian host and its photosynthetic dinoflagellatessymbionts form the basis of coral reef ecosystems. Cnidarians host their symbionts in gastrodermis cells, in a phagocytosis-derived vacuole. Establishment and maintenance of the symbiotic interaction depend on an intimate molecular communication between the two partners. However, environmental and/or anthropogenic disturbances can lead to the breakdown of the symbiotic association, which is responsible for the worldwide decline of coral reefs. The main objectives of my research project are to improve the knowledge regarding symbiosis maintenance and disruption mechanisms, but also to define the molecular key players involved at the symbiotic interface in the sea anemone, Anemonia viridis. First, we have described the cellular mechanisms involved in the different types of symbiosis breackdown. Meanwhile, the characterization of npc1 and npc2 genes (involved in endosomal sterol transport), showed a duplication and a sub-functionalization of the npc2d gene. Both NPC1 and NPC2 proteins are expressed around symbionts. We therefore suggest that the duplicated protein NPC2-d is a biomarker of symbiosis health and that NPC1 protein is a marker of the perisymbiotic membrane. We then developed a protocol to characterize the proteome of the symbiotic interface between the two symbiotic partners. The newly-identified symbiotic key players will increase the general knowledge on the symbiotic interaction and its regulation during both stable and bleaching conditions.
L’endosymbiose trophique établie entre un hôte Cnidaire et ses symbiotes Dinoflagellés photosynthétiques est à l’origine du succès évolutif des écosystèmes coralliens. Les symbiotes sont internalisés par un mécanisme de phagocytose et maintenus dans les cellules du gastroderme de l'hôte. La symbiose est régie par un dialogue moléculaire intime entre les deux partenaires, interrompu lors de perturbations environnementales ou anthropiques, responsables du déclin mondial des récifs coralliens. Les objectifs de mon projet de recherche sont de définir les acteurs moléculaires localisés à l’interface symbiotique chez l’anémone de mer, Anemonia viridis. Premièrement, nous avons étudié les mécanismes cellulaires impliqués dans différents types de rupture de la symbiose et mis en évidence des phénomènes d’apoptose, nécrose et symbiophagie. Parallèlement, nous avons caractérisé chez l’anémone les gènes npc1 et npc2, impliqués chez les vertébrés dans le transport endosomal de stérols, et dont l’expression est modulée par l’état symbiotique. Nous avons pu montrer que le gène npc2d est issus d’une duplication et vraisemblablement d’une sub-fonctionnalisation et que les protéines NPC1 et NPC2 sont exprimées au voisinage des symbiotes. Nous proposons donc que la protéine NPC2-d soit utilisée comme marqueur de l’état de santé des Anthozoaires symbiotiques et que la protéine NPC1 soit un marqueur de la membrane périsymbiotique. Nous avons également développé un protocole afin d’identifier les protéines associées à l’interface symbiotique entre les deux partenaires. A terme, les cibles identifiées permettront une meilleure compréhension des mécanismes qui régulent la relation symbiotique.
https://tel.archives-ouvertes.fr/tel-01673491

NNT : 2015NICE4105
tel-01673491
https://tel.archives-ouvertes.fr/tel-01673491
https://tel.archives-ouvertes.fr/tel-01673491/document
https://tel.archives-ouvertes.fr/tel-01673491/file/2015NICE4105.pdf

Éditeur(s) : HAL CCSD SAGE Publications (UK and US)
Résumé : International audience
Enamel and enameloid, the highly mineralized tooth-covering tissues in living vertebrates, are different in their matrix composition. Enamel, a unique product of ameloblasts, principally contains enamel matrix proteins (EMPs), while enameloid possesses collagen fibrils and probably receives contributions from both odontoblasts and ameloblasts. Here we focused on type I collagen (COL1A1) and amelogenin (AMEL) gene expression during enameloid and enamel formation throughout ontogeny in the caudate amphibian, Pleurodeles waltl. In this model, pre-metamorphic teeth possess enameloid and enamel, while post-metamorphic teeth possess enamel only. In first-generation teeth, qPCR and in situ hybridization (ISH) on sections revealed that ameloblasts weakly expressed AMEL during late-stage enameloid formation, while expression strongly increased during enamel deposition. Using ISH, we identified COL1A1 transcripts in ameloblasts and odontoblasts during enameloid formation. COL1A1 expression in ameloblasts gradually decreased and was no longer detected after metamorphosis. The transition from enameloid-rich to enamel-rich teeth could be related to a switch in ameloblast activity from COL1A1 to AMEL synthesis. P. waltl therefore appears to be an appropriate animal model for the study of the processes involved during enameloid-to-enamel transition, especially because similar events probably occurred in various lineages during vertebrate evolution.
ISSN: 0022-0345

hal-01545475
https://hal.archives-ouvertes.fr/hal-01545475
DOI : 10.1177/0022034514526236