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The brain is the integrative center of all incoming and outgoing signals of the body. As such, the study of the brain may help to infer the paleobiology of extinct species and to discuss the evolutionary history of eco-functional traits. Bats are outstanding by two extreme traits: active flight and echolocation. Actually, the megabats Pteropodidae are unable to echolocate. In the current phylogenetic framework, this family is sister-taxon to a “microbat” clade. Questions therefore regard the sequence of acquisition of the echolocation (common acquisition for bats and secondary loss in megabats, or convergent acquisitions between “microbat” clades) and of the active flight (flight or echolocation first, or concurrent acquisition of both). Evolution of brain and endocranial characteristics have little been studied in bats. Chiropteran “fossil brains”, accessible as casts of the endocranial cavity (‘endocasts’), have been described during the first half of the XXth century, but with limited techniques; no recent work tackled the question of the evolution of the brain morphology in bats. Recent studies rather focus on the brain mass with extant taxa, proposing a general reduction of the bat brain mass through time. The aim of this thesis is therefore to study the bat endocranial cast using modern techniques, both qualitatively and quantitatively. The study of four fossil endocasts of the family Hipposideridae allows to evaluate the potentialities of the study of the endocranial cast in bats. A first nomenclature of the morphology of the endocast is provided. These comparisons, together with analyses of the encephalization quotient variation through time and of the relative masses of the olfactory bulbs and of the paraflocculi, suggest a general conservatism of brain morphology and size in Hipposideridae. The second part of this thesis aims to generalize the endocast nomenclature to the whole Chiroptera order, the quantitative metrics commonly used in modern paleoneurology are also described and discussed. I propose to use a recently developed phylogenetic comparative method designed to benefit from fossil taxa inclusion. The third part focus on Yinpterochiroptera, dichotomy between a “microbats” Rhinolophoidea, and megabats Pteropodidae. I define discrete anatomical characters of the endocast, and find them moderately congruent with the phylogenetic framework, with potential cases of selection through time. Reconstruction of the evolution of the endocranial shape in the major yinpterochiropteran clades, highlights major differences between rhinolophoids and pteropodids and between rhinolophoid families. Analyses of the evolution of relative neural masses drastically change when fossils are included. A general increase of relative brain size is found, contradicting neontological scenarios; on the other hand, olfactory bulbs and paraflocculi relative masses decrease with time. Previously proposed ecological correlates to these relative neural masses are weakly supported, suggesting more complexity than a direct causality. The fourth part regards the whole Chiroptera order level. I describe the first endocranial cast of a stem bat species; it is a typical bat in its morphology, supporting the hypothesis of a common acquisition of echolocation in bats. Its inclusion to the ordinal picture generally confirms hypotheses proposed in the third part, both regarding morphological and relative neural masses evolution. As a general summary, this work constitutes a first step towards bats endocasts study. The correspondences between the endocast morphology and the disposition of soft tissues in the braincase remain to be assessed, other methodologies can be applied (and compared), and inclusion of other fossil taxa should greatly enhance the very first picture of the evolution of the bat brain proposed here.; Le cerveau est le centre d'intégration de tous les signaux entrants et sortants du corps. Son étude peut aider à déduire la paléobiologie des espèces éteintes et à discuter de l'histoire évolutive des traits éco-fonctionnels. Les chauves-souris présentent deux adaptations extrêmes : le vol actif et l'écholocalisation. En réalité, les mégachiroptères (Pteropodidae) sont incapables d'écholocalisation. Cette famille est pourtant le groupe frère d'un clade de "microchiroptères" (écholocalisatrices). Des questions se posent donc sur la séquence d'acquisition de l'écholocalisation (commune chez les chauves-souris et perte secondaire chez les mégachiroptères, ou convergentes entre clades "microchiroptères") et du vol actif. L'évolution des caractéristiques cérébrales et endocrâniennes a été peu étudiée dans cet ordre. Des "cerveaux fossiles" de chiroptères, moulages de la cavité endocrânienne, ont été décrits au cours du XXe siècle, mais aucun travail récent n'a étudié l'évolution de la morphologie du cerveau chez ce groupe. Les études récentes se concentrent plutôt sur la masse cérébrale des taxons actuels, et proposent une réduction générale de la masse cérébrale des chauves-souris au cours du temps. L'objectif de cette thèse est d'étudier le moulage endocrânien des chauves-souris à l'aide de techniques modernes, tant sur le plan qualitatif que quantitatif. Une première étude du moulage endocrânien de quatre Hipposideridae fossiles permet d’évaluer les potentialités du moulage endocrânien chez les chauves-souris et de fournir une première nomenclature révisée. Ces comparaisons, ainsi que les analyses de la variation du quotient d’encéphalisation) au cours du temps et des masses relatives des bulbes olfactifs et des paraflocculi, suggèrent un conservatisme général de la morphologie et de la taille du cerveau chez les Hipposideridae. La deuxième partie généralise la nomenclature de la morphologie des moulages endocrâniens à l'ordre des chiroptères et propose d'utiliser une méthode comparative phylogénétique récente, conçue pour l'inclusion de taxons fossiles. La troisième partie focalise sur les Yinpterochiroptera. Des caractères anatomiques discrets endocrâniens sont définis et s’avèrent modérément congruents avec la phylogénie. L'évolution de la forme endocrânienne des principaux clades yinptérochiroptères met en évidence des différences majeures entre les rhinolophoïdes et les ptéropodidés et entre les familles de rhinolophoïdes. Les résultats des analyses de l'évolution des masses neurales relatives changent radicalement lorsque les fossiles sont inclus. Une augmentation générale de la taille relative du cerveau au cours du temps est trouvée, ce qui contredit les scénarios néontologiques ; alors que les masses relatives des bulbes olfactifs et des paraflocculi diminuent. Les corrélations écologiques précédemment proposées sont faiblement soutenues. La dernière partie traite de l'ordre entier des chiroptères et décrit le premier moulage endocrânien connu d'une espèce “souche” de chauve-souris ; son moulage endocrânien est typique de l’ordre, soutenant l'hypothèse d'une acquisition commune de l'écholocalisation. Son inclusion dans le contexte ordinal confirme les hypothèses proposées dans la 3eme partie, pour l'évolution morphologique et les masses neurales relatives. Ce travail constitue un premier pas vers l'étude des moulages endocrâniens de chauves-souris. Les correspondances entre moulages endocrâniens et tissus mous restent à évaluer et l'inclusion d'autres taxons fossiles devrait grandement améliorer la toute première image de l'évolution du cerveau des chauves-souris proposée ici.

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Zona pellucida (ZP) is a barrier that the sperm has to pass through in order to reach the perivitelline space (EPV), which contains the oocyte. Fusion of gametes leads to the formation of a zygote, which will become a new being, unless polyspermy happens. This phenomenon constitutes a fertilization abnormality, harmful to development. Mechanisms implemented by the zygote to prevent other fusion are partially understood. The ZP rigidifies to prevent other sperm from entering the perivitelline space. However, this block is only effective after one hour of fusion, period during which other sperm may also reach the zygote. This suggests that there should be another mechanism to counter fusion of other sperm. By conducting a statistical study in mice, I have proven the existence of this second mechanism and its physiological aspect. I then sought out to characterize it with the following working hypothesis: after initial fusion, the release of JUNO, an oocyte protein essential for fertilization via its binding with its spermatic ligand IZUMO1, into the EPV alters the adhesive and fusogenic capacities of any sperm entering the EPV. By combining molecular biology, quantitative imaging, micromanipulation and laser ablation I studied the impact of the JUNO protein on the fusion capacity of the sperm by two complementary approaches, one using sperm directly recovered in the EPV of zygotes, and two using sperm artificially put in presence of JUNO. In parallel, in order to kinetically characterize the release of JUNO and its attachment to sperm, entering the EPV, I undertook to genetically modify JUNO expressed by the oocyte, so as to make it fluorescent without altering its function.; La zone pellucide (ZP) est une barrière que le spermatozoïde doit franchir pour atteindre l’espace périvitellin (EPV) où se trouve l’ovocyte. Leur fusion conduit au zygote qui deviendra un nouvel être si aucune autre fusion engendrant une polyspermie n’a lieu. Celle-ci constitue une anomalie de la fécondation, délétère au développement. Les mécanismes mis en œuvre par le zygote pour l’empêcher ne sont que partiellement connus. Une rigidification de la ZP empêchant l’entrée de spermatozoïdes dans l’EPV se met en place. Ce blocage est effectif une heure après fusion, laissant la possibilité à d’autres spermatozoïdes d’entrer en contact avec le zygote. Un autre mécanisme de blocage doit exister pour parer leur fusion. Par une étude statistique chez la souris, j’ai prouvé l’existence et de ce second mécanisme, et son aspect physiologique. J’ai cherché à le caractériser en partant de l’hypothèse suivante : suite à une première fusion, le relargage de JUNO, protéine ovocytaire essentielle à la fécondation via sa liaison avec son ligand spermatique IZUMO1, altère les capacités adhésives et fusogènes des spermatozoïdes pénétrant l’EPV. En combinant biologie moléculaire, imagerie quantitative et micromanipulation j’ai étudié l’impact de la protéine JUNO sur la capacité de fusion du spermatozoïde par deux approches : l’une utilisant les spermatozoïdes récupérés dans l’EPV de zygotes, et l’autre des spermatozoïdes artificiellement mis en présence de JUNO. Afin de caractériser cinétiquement le relargage de JUNO et son accrochage aux spermatozoïdes pénétrant dans l’EPV, j’ai entrepris de modifier génétiquement JUNO, de façon à le rendre fluorescent sans altérer sa fonction.

Le parc de la Lékédi, ancien lieu de ranching touristique, souhaite aujourd’hui se reconvertir en aire de préservation de la biodiversité locale. Pour cela, il était nécessaire de réaliser un diagnostic de biodiversité afin de déterminer les enjeux de cette aire. Le travail réalisé a permis de démarrer ce diagnostic en s’intéressant au taxon des mammifères. L’étude réalisée a consisté en des relevés de faune pendant 1236 jours caméra, sur 36 emplacements répartis à travers les 14000ha du parc. Les résultats obtenus ont permis de valider la présence de 31 espèces de mammifères au sein du parc et de confirmer l’intérêt majeur qu’il présente pour la conservation des grands primates et de plusieurs autres espèces menacées. Cette étude a permis de poser les bases d’un examen méthodique du parc. Si les résultats obtenus sont déjà très encourageants, ils mettent aussi en lumière l’intérêt qu’il y aurait à examiner les autres taxons et à réaliser un suivi de longue durée, éventuellement ciblé sur les espèces à enjeux.

Prioritization of introduction pathways is seen as an important component of the management of biological invasions. We address whether established alien plants, mammals, freshwater fish and terrestrial invertebrates with known ecological impacts are associated with particular introduction pathways (release, escape, contaminant, stowaway, corridor and unaided). We used the information from the European alien species database DAISIE (www.europe-aliens.org) supplemented by the EASIN catalogue (European Alien Species Information Network), and expert knowledge. Plants introduced by the pathways release, corridor and unaided were disproportionately more likely to have ecological impacts than those introduced as contaminants. In contrast, impacts were not associated with particular introduction pathways for invertebrates, mammals or fish. Thus, while for plants management strategies should be targeted towards the appropriate pathways, for animals, management should focus on reducing the total number of taxa introduced, targeting those pathways responsible for high numbers of introductions. However, regardless of taxonomic group, having multiple introduction pathways increases the likelihood of the species having an ecological impact. This may simply reflect that species introduced by multiple pathways have high propagule pressure and so have a high probability of establishment. Clearly, patterns of invasion are determined by many interacting factors and management strategies should reflect this complexity

DNA methylation plays an important role in repressing the expression of “parasitic” DNAs, such as transposable elements, which have invaded our genomes. Mammals have three DNA methyltransferase enzymes. Barau et al. discovered a fourth DNA methyltransferase enzyme in mice. The enzyme DNMT3C is a duplication of DNMT3B and is found in male germ cells. There it targets evolutionarily young transposons, of which there is a heavy burden in the mouse genome. DNMT3C methylates and silences the young transposons, preserving male fertility.Science, this issue p. 909DNA methylation is prevalent in mammalian genomes and plays a central role in the epigenetic control of development. The mammalian DNA methylation machinery is thought to be composed of three DNA methyltransferase enzymes (DNMT1, DNMT3A, and DNMT3B) and one cofactor (DNMT3L). Here, we describe the discovery of Dnmt3C, a de novo DNA methyltransferase gene that evolved via a duplication of Dnmt3B in rodent genomes and was previously annotated as a pseudogene. We show that DNMT3C is the enzyme responsible for methylating the promoters of evolutionarily young retrotransposons in the male germ line and that this specialized activity is required for mouse fertility. DNMT3C reveals the plasticity of the mammalian DNA methylation system and expands the scope of the mechanisms involved in the epigenetic control of retrotransposons.

The periaqueductal gray (PAG) is a mesencephalic brain structure involved in the expression of numerous behaviours such as maternal, sexual and emotional. Histological approaches showed the PAG is composed by subdivisions with specific cell organisation, neurochemical composition and connections with the rest of the brain. The comparison of studies performed in rodents and cats as the most often examined species, suggests that PAG organisation differs between mammals. However, we should also consider the plurality of the methods used in these studies that makes difficult the comparison of the PAG organisation between species. Therefore, to study the PAG in all mammals including human, the most relevant in vivo imaging method seems to be the magnetic resonance imaging (MRI). The purpose of this review was to summarize the knowledge of the anatomical organisation of the PAG in mammals and highlights the benefits of MRI methods to extend this knowledge. Results obtained by MRI so far support the conclusions of ex vivo studies, especially to describe the subdivisions and the connections of the PAG. In these latter, diffusion-weighted MRI and functional connectivity seem the most appropriate methods. In conclusion firstly, the MRI seems to be the best judicious method to compare species and improve the comprehension of the role of the PAG. Secondly, MRI is an in vivo method aimed to manage repeated measures in the same cohort of subjects allowing to study the impact of aging and the development on the anatomical organisation of the PAG.

To fulfil the requirements for methionine, animal diets are widely supplemented with synthetic methionine sources such as L-methionine (L-Met), DL-methionine (DL-Met), and DL-2-hydroxy-4-(methylthio)-butanoic acid (DL-OH-Met). The objective of this study is to calculate the energy cost of the different conversion steps leading to L-Met and to propose energy equivalence values for DL-Met and DL-OH-Met, relative to that of L-Met. The conversion of DL-OH-Met to L-Met involves a nitrogen-sparing effect, because excess nitrogen can be used for the transformation of DL-OH-Met to L-Met, rather than being excreted as urea or uric acid Consequently, the ME-to-GE ratio of DL-OH-Met is 109% in mammals and 114% in birds, compared to the value of DL-Met. Because of differences in metabolism and the formation of hydrogen peroxide in the conversion to L-Met, the NE-to-ME ratios are 96% for DL-Met and 100% for DL-OH-Met in both mammals and birds. The conversion of DL-OH-Met to L-Met is therefore energetically less costly than the conversion of DL-Met. The stoichiometric approach presented here only considers the biochemical conversion steps, without considering the cost of transport and further transformation steps.

Tooth development is essentially studied in mice, the favorite mammalian model in biology. However, mice do not replace their teeth on contrary to numerous mammals. So, the mechanisms involved in mammalian tooth replacement are still unknown. In this thesis, we focused on mammalian dental development and replacement using the European rabbit Oryctolagus cuniculus as animal model. The European rabbit is already sequenced, used in biomedical field, has a short gestation time and replaced its teeth, so rabbit seemed to be a relevant model in dental research.Rabbit dental development was not defined, so we first performed a histo-morphological study to characterize the development of deciduous and permanent teeth. 3D soft tissue reconstructions were performed at different embryonic stages to obtain a chronology of tooth development and replacement. This chronology begins with the first morphological observations of the initiation of the development of the first tooth until the mineralization of the last tooth to develop.Then, we identified in the bibliography candidate genes potentially involved in dental replacement. We studied the expression profiles of these genes in order to better understand the spatio-temporal regulation of tooth replacement in rabbits.We then returned our results to rabbit development in an evolutionary context. Thus, we performed a comparative anatomy study in the current lagomorphs and some fossils in order to identify dental morphological variations during their evolutionary history. We were particularly interested in the setting of cusps during odontogenesis as well as in the variations of the occlusal surface of the upper cheek teeth throughout the life of rabbits and other lagomorphs. Comparing changes during evolution with those observed during dental ontogeny in rabbits allow us to identify heterochronous processes of development. We have shown that the current molar rabbit follows a process of peramorphosis, so an overdevelopment compared to fossil lagomorphs.The rabbit is thus a promising animal model in developmental and evolutionary biology to better understand the implementation of mammalian tooth replacement and tooth shape variations during mammalian evolution.; Le développement dentaire est essentiellement étudié chez la souris, modèle mammifère le plus commun en biologie. Cependant, contrairement à la majorité des mammifères, les souris ne remplacent pas leurs dents. Ainsi, les mécanismes impliqués dans le remplacement dentaire mammalien sont encore inconnus. Au cours de cette thèse, nous nous sommes intéressés au développement et remplacement dentaire mammalien en utilisant le lapin Oryctolagus cuniculus comme modèle d’étude. Le lapin étant déjà séquencé, utilisé en recherche biomédicale avec une période de gestation courte et remplaçant ses dents, il semblait être un modèle pertinent en odontologie. Le lapin était un modèle méconnu du point de vue du développement dentaire, nous avons donc d’abord réalisé une étude histo-morphologique afin de caractériser la mise en place des dents déciduales et permanentes. Des reconstructions 3D des tissus mous ont été réalisés à différents stades embryonnaires afin d’obtenir une chronologie du développement et remplacement dentaire. Cette chronologie commence aux premières observations morphologiques de l’initiation du développement des premières dents jusqu’à la minéralisation des dernières dents à se développer.Puis, suite à l’identification dans la bibliographie de gènes candidats potentiellement impliqués dans le remplacement dentaire, nous avons étudiés les profils d’expressions de ces gènes afin de mieux comprendre la régulation spatio-temporelle du remplacement dentaire chez le lapin. Nous avons ensuite replacé nos résultats sur le développement chez le lapin dans un contexte évolutif. Ainsi, nous avons réalisé une étude d’anatomie comparée chez les lagomorphes actuels et quelques fossiles afin d’identifier des variations morphologiques dentaires au cours de leur histoire évolutive. Nous nous sommes particulièrement intéressé à la mise en place des cuspides au cours de l’odontogénèse ainsi qu’aux variations de la surface occlusale des dents supérieure tout au long de la vie des lapins et autres lagomorphes. En comparant les variations au cours de l’évolution avec celles observées lors de l’ontogénie dentaire chez le lapin nous avons identifié des processus d’hétérochronies du développement. Nous avons ainsi montré que la molaire actuelle du lapin suit un processus de péramorphose, donc de surdéveloppement, en comparaison aux lagomorphes fossiles. Le lapin est ainsi un modèle animal prometteur en biologie du développement et en évolution afin de mieux comprendre la mise en place du remplacement dentaire mammalien ainsi que les variations de forme dentaire au cours de l’évolution des mammifères.

We present version 10 of OrthoMaM, a database of orthologous mammalian markers. OrthoMaM is already 11 years old and since the outset it has kept on improving, providing alignments and phylogenetic trees of high-quality computed with state-of-the-art methods on up-to-date data. The main contribution of this version is the increase in the number of taxa: 116 mammalian genomes for 14,509 one-to-one orthologous genes. This has been made possible by the combination of genomic data deposited in Ensembl complemented by additional good-quality genomes only available in NCBI. Version 10 users will benefit from pipeline improvements and a completely redesigned web-interface.

Methanogenic archaea occupy a functionally important niche in the gut microbial ecosystemof mammals. Our purpose was to quantitatively characterize the dynamics of methanogenesisby integrating microbiology, thermodynamics and mathematical modelling. For that, invitro growth experiments were performed with pure cultures of key methanogens from thehuman and ruminant gut, namely Methanobrevibacter smithii, Methanobrevibacter ruminantiumand Methanobacterium formicium. Microcalorimetric experiments were performed toquantify the methanogenesis heat flux. We constructed an energetic-based mathematicalmodel of methanogenesis. Our model captured efficiently the dynamics of methanogenesiswith average concordance correlation coefficients of 0.95 for CO2, 0.98 for H2 and 0.97 forCH4. Together, experimental data and model enabled us to quantify metabolism kineticsand energetic patterns that were specific and distinct for each species despite their use ofanalogous methane-producing pathways. Then, we tested in silico the interactions betweenthese methanogens under an in vivo simulation scenario using a theoretical modelling exercise.In silico simulations suggest that the classical competitive exclusion principle is inapplicableto gut ecosystems and that kinetic information alone cannot explain gut ecologicalaspects such as microbial coexistence. We suggest that ecological models of gut ecosystemsrequire the integration of microbial kinetics with nonlinear behaviours related to spatialand temporal variations taking place in mammalian guts. Our work provides novel informationon the thermodynamics and dynamics of methanogens. This understanding will beuseful to construct new gut models with enhanced prediction capabilities and could havepractical applications for promoting gut health in mammals and mitigating ruminant methaneemissions.

La maîtrise du moment de l’ovulation chez les mammifères d’élevage permet d’améliorer la fertilité, la gestion des mises bas, mais les méthodes actuelles sont basées sur l’utilisation de fortes doses d’hormones. Cette revue présente de nouveaux paradigmes pour maitriser le moment de l’ovulation, respectueux de la physiologie de l’animal, sans supplémentation hormonale basés sur la connaissance des mécanismes physiologiques.[br/] [br/] Le déclenchement de l’ovulation peut se faire selon deux modes chez les mammifères : spontané et provoqué. L’ovulation spontanée intervient au cours du cycle œstral sous l’effet de facteurs internes hormonaux. L’ovulation provoquée est déclenchée par l’accouplement avec un mâle. Dans les deux cas, c’est une augmentation de la sécrétion de GnRH qui conduit à l’augmentation de LH qui provoque l’ovulation. Les facteurs qui conduisent à l’augmentation de sécrétion de GnRH sont différents selon les deux modalités : principalement la kisspeptine (ovulation spontanée) et le b-NGF (ovulation provoquée). Les protocoles d’induction de l’ovulation actuels reposent sur une action directe sur l’ovaire, grâce à l’utilisation de gonadotropines hétérologues, ou bien par une action sur l’hypophyse grâce aux agonistes du GnRH. Ces protocoles présentent différents inconvénients : perte d’efficacité dans le temps, stimulation supra-physiologique qui peut être délétère, problème éthique posé par l’obtention de certaines molécules. De nouveaux paradigmes d’induction de l’ovulation ciblant l’hypothalamus, et favorisant un déclenchement physiologique de l’ovulation sans supplémentation en hormones sont en cours de développement. Cette revue a pour objectif de présenter au lecteur les mécanismes intimes impliqués dans la régulation et le déclenchement de l’ovulation ainsi que deux approches nouvelles respectueuses de la physiologie de l’animal et de l’environnement., The triggering of ovulation in mammals can be done according to two modes: spontaneous and provoked. Spontaneous ovulation occurs during the estrous cycle as a result of internal endocrine factors. Induced ovulation is triggered by mating. In both cases, it is the increase in GnRH secretion that leads to an increase in LH that causes ovulation. The factors involved in the stimulation of GnRH secretion are different according to the two modalities, mainly kisspeptin for spontaneous ovulators and beta-NGF for provoked ovulators. Current protocols used to induce ovulation rely on a direct action on the ovary, through the use of heterologous gonadotropins, or by an action on the pituitary gland with GnRH agonists. These protocols present different disadvantages: loss of activity with time, supra-physiological stimulation, ethic questioning about the production of some of these products. New paradigms for triggering ovulation by targeting the hypothalamus, respectful of animal welfare and the environment are presented in this review. This review aims to introduce the reader to the cellular and molecular mechanisms involved in the regulation and triggering of ovulation as well as two new approaches that are being developed and that are respectful of the animal and of its environment.

International audience; Chaperone-mediated autophagy (CMA) is a major pathway of lysosomal proteolysis essential for the control of intermediary metabolism. So far, the absence of any identifiable LAMP2A—a necessary and limiting protein for CMA—outside of the tetrapod clade, led to the paradigm that this cellular function was (presumably) restricted to mammals and birds. However, after we identified expressed sequences displaying high sequence homology with the mammalian LAMP2A in several fish species, our findings challenge that view and suggest that CMA likely appeared much earlier during evolution than initially thought. Hence, our results do not only shed an entirely new light on the evolution of CMA, but also bring new perspectives on the possible use of complementary genetic models, such as zebrafish or medaka for studying CMA function from a comparative angle/view.

International audience; Nanos are RNA-binding proteins playing crucial roles in germ cell development and maintenance.Based on phylogenetic and synteny analyses, this study reveals that nanos1 gene has undergonemultiple duplications and gene copies losses in Vertebrates. Chondrichthyan species display twonanos1 genes (named nanos1A/1B), which were both retrieved in some Osteichthyes at basal positionsin Sarcopterygii and Actinopterygii lineages. In contrast, Teleosts have lost nanos1A but duplicatednanos1B leading to the emergence of two ohnologs (nanos1Ba/1Bb), whereas Tetrapods have lostnanos1B gene. The two successive nanos gene duplications may result from the second and third wholegenome duplication events at the basis of Vertebrates and Teleosts respectively. The expression proflesof nanos1A and nanos1B paralogs were characterized in the dogfsh, Scyliorhinus canicula. Nanos1A wasstrongly expressed in brain and also localized in all germ cell types in the polarized testis. In contrast,nanos1B was detected in testis with the highest expression in the germinative zone. In addition,Nanos1B protein was predominantly located in the nuclei of male germinal cells. In the ovary, bothparalogs were detected in germinal and somatic cells. Our study opens new perspectives concerning thecomplex evolution of nanos1 paralogs and their potential distinct roles in Vertebrates gonads.

Supplemental information for this article can be found online at:http://dx.doi.org/10.7717/peerj.5534#supplemental-information; The family of forkhead box (Fox) transcription factors regulates gonadogenesis and embryogenesis, but the role of in reproduction is unknown. Evolutionary history of in vertebrates was examined and the gene was found to exist in most vertebrates, including mammals, ray-finned fish, amphibians, and sauropsids. By quantitative PCR and RNA-seq, we found that had an ovarian-specific expression in zebrafish, a common feature of maternal-effect genes. In addition, it was demonstrated using in situ hybridization that was a maternally-inherited transcript that was highly expressed even in early-stage oocytes and accumulated in the developing eggs during oogenesis. We also analyzed the function of in female reproduction using a zebrafish CRISPR/cas9 knockout model. It was observed that embryos from the -deficient females had a significantly lower survival rate whereby they either failed to undergo cell division or underwent abnormal division that culminated in growth arrest at around the mid-blastula transition and early death. These mutant-derived eggs contained dramatically increased levels of , a cell cycle inhibitor, and reduced , a component of mTOR and regulator of cell survival, which were in line with the observed growth arrest phenotype. Our study shows for the first time that is an essential maternal-effect gene and may be required for proper cell division and survival via the p21 and mTOR pathways. These novel findings will broaden our knowledge on the functions of specific maternal factors stored in the developing egg and the underlying mechanisms that contribute to reproductive success.

Modéliser les effets du changement climatique sur la biodiversité en région Nouvelle-Aquitaine nécessite des observations quantitatives sur l’abondance des espèces dans le temps et l’espace sur le terrain, afin d’obtenir des résultats significatifs. Des suivis protocolés sur le long terme ont ainsi été mis en place dans le cadre du programme les sentinelles du climat. Une vingtaine d’indicateurs biologiques sont suivis par type d’écosystème de 2016 à 2021. Ces suivis génèrent des milliers de données biologiques et des millions de données climatiques associés. Ce rapport présente la mise en place d’une réflexion de création d’une base de données spécifique. Cette base devient nécessaire pour : 1) gérer l’accumulation et la validation des informations, pour des analyses mécanistiques et statistiques dans le temps, dans le cadre du programme ; 2) permettre leurs exploitations pour la modélisation des répartitions spatio-temporelles des espèces actuelles et pour des projections dans différents scénarios de changement climatique ; 3) établir un état « 0 » répertorié, géré, analysé, diffusé dans l’objectif d’une comparaison d’état dans plusieurs décennies. L’outil de saisie proposé est à ce stade un gabarit standard de description des métadonnées et des données brutes des suivis naturalistes. Ce gabarit est associé à une base de fiches de terrain permettant de localiser précisément les unités d’échantillonnage.

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Scientific reports 7, 44420 (2017). doi:10.1038/srep44420, Published by Nature Publishing Group, London

un poster présenté; International audience; Duplication of nanos1 gene and expression in dogfish gonads. 6. International Workshop on the Biology of Fish Gametes

Genes encoding mammalian oviductal proteins involved in fertilization are subjected to gene death and positive selection. 21. Annual Conference of the European Society for Domestic Animal Reproduction (ESDAR)

Après la découverte, au printemps 1991, par les deux associations spéléologiques du département, d’une accumulation d’ossements dans le réseau d’un système karstique, une opération de sauvetage urgent a été entreprise. L’opération avait pour but d’évaluer l’importance du gisement, de prélever en quantité des brèches fossilifères à différents niveaux du réseau et de mener une étude géologique détaillée pour comprendre les mécanismes de la mise en place de ce remplissage fossilifère. Le réseau ...

In mammals, the main olfactory system displays all the structural and functional characteristics at the last third of the gestational stage. Thus, the fetus is able to detect, to discriminate, but also to memorize the odorants present in the amniotic fluid in which it bathes. In the rodent, these odors memorized in utero are fundamental for the survival of the newborn at birth by allowing it to trend itself towards food sources. Afterwards, odorants are guiding the newborn to olfactory and food choices and are promoting subsequent learning. It is known that the mother's diet varies the olfactory keys of the biological fluids (amniotic fluid, milk) and thus modifies the nature of the olfactory sources encountered by the fetus and then the newborn in the perinatal period. The neuroanatomic and functional consequences of this impregnation are the subject of recent studies. The objective of this thesis was to characterize the effects of perinatal odor exposure on the maturation and functioning of the olfactory system in relation to the development of olfactory preferences and to a stressing challenge at weaning. For that, we set up a model of perinatal odor exposure through maternal feeding in the mI7-GFP murine transgenic strain expressing the olfactory receptor I7 coupled with the Green Fluorescent Protein (GFP). We evaluated the neuroanatomic, molecular and behavioral consequences on the pups before weaning, and their evolution over time by focusing our efforts on the postnatal stages 3 (PND3), PND12-14 and PND21. Due to the fragility of the transgenic strain, we worked on mI7-GFP mice pups crossfostered by CD1 mice mothers raised under the same conditions after having validated the presence of heptanal in the amniotic fluid of mI7-GFP mice and the milk of CD1 mice by GC-MSMS. We characterized the effects of perinatal odor exposure on the maturation and functioning of the olfactory system in relation to the olfactory preference until weaning (mI7-GFP mice pups under CD1 adoptive mothers) and on the stress reaction to maternal separation at weaning (CD1 mice pups under biological mother). Our results show that perinatal exposure to heptanal leads to a significant increase in the number of I7 glomeruli in the olfactory bulb (OB) associated to a slight modification of the tissue homeostasis in the olfactory mucosa (OM) and to subtle differencies in heptanal sensitivity and preferences, that are amplified at PND21. From a molecular point of view, these effects are associated to a down-regulation of the expression of the I7 receptor and genes of neuronal signaling and an odorantspecific decrease in EOG response which may highlight a modification of the cellular dynamics. Finally, the effect of perinatal exposure to heptanal on the response to stressing conditions after maternal separation was assessed by recording CD1 mice pups grown under the same conditions than fostered mi7 mice on odorized and non odorized open-field. We showed that the reaction of odorized mice in the open field at PND21 is attenuated when the odorant is present in the environment, compared to non odorized mice that display anxiety-like behavior. Overall, this study demonstrates the consequences of a perinatal odorant exposure in the young, in terms of behavior (olfactory preference and anxiety), structural and molecular plasticity of the olfactory system, on a transgenic strain for which we had little available data.; Chez les mammifères, le système olfactif principal est fonctionnel dans le dernier tiers du stade gestationnel. Le fœtus est donc capable de détecter avec sensibilité, discriminer, et mémoriser les odorants présents dans le liquide amniotique dans lequel il baigne. Chez le rongeur, ces odorants mémorisés in utero sont fondamentaux pour la survie du nouveau-né à la naissance en lui permettant de s’orienter vers la mamelle et de déclencher la tétée. Par la suite, ces odorants vont guider le nouveau-né dans ses choix olfactifs et alimentaires et favoriser ses apprentissages ultérieurs. Or, on sait que l’alimentation de la mère fait varier les clés olfactives des fluides biologiques (liquide amniotique, lait) et donc modifie la nature des sources olfactives rencontrées par le fœtus, puis le nouveau-né dans la période périnatale. Dans le but d’évaluer l’impact d’une exposition odorante périnatale sur le fonctionnement et la maturation du système olfactif en relation avec le développement de préférences médiées par l’olfaction et la modulation du stress au moment du sevrage, nous avons mis en place un modèle d’exposition odorante périnatale via l’alimentation maternelle dans une lignée transgénique murine exprimant le récepteur olfactif I7 couplé à une protéine fluorescente, dont l’odorant préférentiel est l’heptanal. Après validation de la présence d’heptanal dans le liquide amniotique et le lait de ces souris par GC-MS-MS, nos résultats montrent que l’exposition périnatale à l’heptanal entraine une augmentation significative du nombre de glomérules I7 présents au niveau du bulbe olfactif à PN12 par rapport aux animaux contrôles sans modification notable de l’homéostasie tissulaire ou de la transcription du gène I7 au niveau de la muqueuse olfactive. Ce changement structural important au niveau des projections axonales du bulbe olfactif s’accompagne d’un faible effet sur le comportement olfactif des souriceaux dont les capacités de discrimination ne sont que très faiblement améliorées par rapport aux souriceaux non exposés. A PN21, l’effet de l’exposition odorante sur le nombre de glomérules I7 est atténué, mais reste significatif. A ce stade, les souriceaux odorisés montrent une attraction olfactive pour l’heptanal par rapport au groupe contrôle non exposé, bien que l’effet sur un choix entre aliment odorisé ou pas soit plus contrasté. D’un point de vue moléculaire, ces effets sont associés à une diminution de l’expression du récepteur I7, et de gènes de la signalisation neuronale pouvant traduire une modification de la dynamique cellulaire. Et comme le montrent les résultats obtenus en électro-olfactogramme à cet âge, la sensibilité de la muqueuse olfactive vis-à-vis de l’heptanal est diminuée alors qu’elle ne l’est pas pour d’autres composés odorants. Ces travaux montrent que l’exposition périnatale à un odorant s’accompagne d’effets précoces sur le système olfactif qui impactent son organisation et d’effets sur les choix olfactifs qui se renforcent au cours du développement. Enfin, l’effet d’une exposition périnatale à l’heptanal sur la réponse à des conditions stressantes après séparation maternelle au moment du sevrage a été évaluée en enregistrant des souriceaux CD1 élevés dans les mêmes conditions d’odorisation que les souriceaux mI7-GFP adoptés, en open-field odorisé ou non. Nous avons montré que la réaction de stress des souriceaux à PN21, exposés en périnatal à l’heptanal, dans l’open field, est atténuée lorsque l’heptanal est présent dans l’environnement, comparé à la réaction des souriceaux non exposés qui affichent un comportement d’anxiété. Dans l’ensemble, cette étude a donc permis de mettre en évidence les conséquences en terme d’effets comportementaux (préférences médiées par l’olfaction et diminution du stress), structuraux et moléculaires, d’une exposition odorante périnatale chez le jeune, à l’aide d’une lignée transgénique pour laquelle nous disposions de peu de données.

Line transect surveys are widely used in Neotropical rainforests to estimate the population abundance of medium- and large-sized vertebrates. The use of indices such as encounter rate has been criticized because the probability of animal detection may fluctuate due to the heterogeneity of environmental conditions among sites. In addition, the morphological and behavioral characteristics (biological traits) of species affect their detectability. In this study, we compared the extent to which environmental conditions and species' biological traits bias abundance estimates in terra firme rainforests in French Guiana. The selected environmental conditions included both physical conditions and forest structure covariates, while the selected biological traits included the morphological and behavioral characteristics of species. We used the distance sampling method to model the detection probability as an explicit function of environmental conditions and biological traits and implemented a model selection process to determine the relative importance of each group of covariates. Biological traits contributed to the variability of animal detectability more than environmental conditions, which had only a marginal effect. Detectability was best for large animals with uniform or disruptive markings that live in groups in the canopy top. Detectability was worst for small, solitary, terrestrial animals with mottled markings. In the terra firme rainforests that represent ~80% of the Amazonia and Guianas regions, our findings support the use of relative indices such as the encounter rate to compare population abundance between sites in species-specific studies. Even though terra firme rainforests may appear similar between regions of Amazonia and the Guianas, comparability must be ensured, especially in forests disturbed by human activity. The detection probability can be used as an indicator of species' vulnerability to hunting and, thus, to the risk of local extinction. Only a few biological trait covariates are required to correctly estimate the detectability of the majority of medium- and large-sized vertebrates. Thus, a biological trait model could be useful in predicting the detection probabilities of rare, uncommon, or localized species for which few data are available to fit the detection function.

BACKGROUND AND PURPOSE: Neonicotinoid insecticides are described as poor agonists of mammalian nicotinic ACh receptors. In this paper, we show that their effects on mammalian nicotinic receptors differ between compounds. EXPERIMENTAL APPROACH: Two‐electrode voltage‐clamp electrophysiology was used to characterize the pharmacology of three neonicotinoid insecticides on nicotinic α7 receptors expressed in Xenopus oocytes. Single and combined application of clothianidin, acetamiprid and thiamethoxam were tested. RESULTS: Two neonicotinoid insecticides, clothianidin and acetamiprid, were partial agonists of mammalian neuronal α7 nicotinic receptors, whereas another neonicotinoid insecticide, thiamethoxam, which is converted to clothianidin in insect and plant tissues, had no effect. Pretreatment with clothianidin and acetamiprid (10 μM) ACh significantly enhanced the subsequent currents evoked by ACh (100 μM ) whereas pretreatment with thiamethoxam (10 μM) reduced ACh‐induced current amplitudes.A combination of the three neonicotinoids decreased the ACh‐evoked currents. CONCLUSIONS AND IMPLICATIONS: The present findings suggest that neonicotinoid insecticides differ markedly in their direct effects on mammalian α7 nicotinic ACh receptors and can also modulate ACh‐induced currents. Furthermore, our data indicate a previously unknown modulation of mammalian α7 nicotinic receptors by a combination of clothianidin, acetamiprid and thiamethoxam. LINKED ARTICLES: This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc

Remerciements :Hugues Dardente, Ludovic Calandreau and Vincent Aucagne for critical reading of the manuscript and Vincent Robert and Didier Lomet for their invaluable contribution to the realization of experiments; The discovery of the hypothalamic neuropeptide kisspeptin and its receptor (KISS1R) have dramatically improved our knowledge about the central mechanisms controlling reproduction. Kisspeptin neurons could be considered the hub where internal and external information controlling reproduction converge. The information is here elaborated and the command dispatched to GnRH neurons, the final output of the brain system controlling reproduction. Several studies have shown that in mammals administration of kisspeptin could finely modulate many aspects of reproduction from puberty to ovulation. For example in ewes kisspeptin infusion triggered ovulation during the non-breeding season and in prepubertal rat repeated injections advanced puberty onset. However, especially in livestock, the suboptimal pharmacological properties of endogenous kisspeptin, notably it short half-life and consequently its poor pharmacodynamics, fetters its use to experimental setting. To overcome this issue synthetic KISS1R agonists, mainly based on kisspeptin backbone, were created. Their more favorable pharmacological profile, longer half-life and duration of action, allowed to perform promising initial experiments for controlling ovulation and puberty. Additional experiments and further refinement of analogs would still be necessary to exploit fully the potential of targeting the kisspeptin system. Nevertheless, it is already clear that this new strategy may represent a breakthrough in the field of reproduction control.

Producción Científica, Signal transduction in sensory neurons of the mammalian vomeronasal organ (VNO) involves the opening of the canonical transient receptor potential channel Trpc2, a Ca2+-permeable cation channel that is activated by diacylglycerol and inhibited by Ca2+-calmodulin. There has been a long-standing debate about the extent to which the second messenger inositol 1,4,5-trisphosphate (InsP3) and type 3 InsP3 receptor (InsP3R3) are involved in the opening of Trpc2 channels and in sensory activation of the VNO. To address this question, we investigated VNO function of mice carrying a knockout mutation in the Itpr3 locus causing a loss of InsP3R3. We established a new method to monitor Ca2+ in the endoplasmic reticulum of vomeronasal sensory neurons (VSNs) by employing the GFP-aequorin protein sensor erGAP2. We also performed simultaneous InsP3 photorelease and Ca2+ monitoring experiments, and analysed Ca2+ dynamics, sensory currents, and action potential or field potential responses in InsP3R3-deficient VSNs. Disruption of Itpr3 abolished or minimized the Ca2+ transients evoked by photoactivated InsP3, but there was virtually no effect on sensory activation of VSNs. Therefore, InsP3R3 is dispensable for primary chemoelectrical transduction in mouse VNO. We conclude that InsP3R3 is not required for gating of Trpc2 in VSNs., Deutsche Forschungsgemeinschaf (grant CH920/2-1), Sonderforschungsbereich 894 (project A17), Transregio - SFB (projects P09 and P10), Ministerio de Economía, Industria y Competitividad (grant BFU2014-53469P)

Astroviruses are known to infect humans and a wide range of animal species, and can cause gastroenteritis in their hosts. Recent studies have reported astroviruses in bats in Europe and in several locations in China. We sampled 1876 bats from 17 genera at 45 sites from 14 and 13 provinces in Cambodia and Lao PDR respectively, and tested them for astroviruses. Our study revealed a high diversity of astroviruses among various Yangochiroptera and Yinpterochiroptera bats. Evidence for varying degrees of host restriction for astroviruses in bats was found. Furthermore, additional Pteropodid hosts were detected. The astroviruses formed distinct phylogenetic clusters within the genus Mamastrovirus, most closely related to other known bat astroviruses. The astrovirus sequences were found to be highly saturated indicating that phylogenetic relationships should be interpreted carefully. An astrovirus clustering in a group with other viruses from diverse hosts, including from ungulates and porcupines, was found in a Rousettus bat. These findings suggest that diverse astroviruses can be found in many species of mammals, including bats., Highlights • Diverse astroviruses detected in bats in Lao PDR and Cambodia • High polymorphism of astroviruses found in insectivorous and frugivorous bats • High level of genome saturation and hypermutation potential evidenced in astrovirus • Detection of additional astrovirus bat hosts, i.e. nectar bats from the genus Eonycteris • Discovery of a new species of astrovirus in fruit bats (Rousettus sp.), Graphical abstract. Image 1

International audience; BACKGROUND:We previously showed that the homeodomain transcription factor HOXB9 is expressed in mammalian oocytes and early embryos. However, a systematic and exhaustive study of the localization of the HOXB9 protein, and HOX proteins in general, during mammalian early embryonic development has so far never been performed.RESULTS:The distribution of HOXB9 proteins in oocytes and the early embryo was characterized by immunofluorescence from the immature oocyte stage to the peri-gastrulation period in both the mouse and the bovine. HOXB9 was detected at all studied stages with a dynamic expression pattern. Its distribution was well conserved between the two species until the blastocyst stage and was mainly nuclear. From that stage on, trophoblastic cells always showed a strong nuclear staining, while the inner cell mass and the derived cell lines showed important dynamic variations both in staining intensity and in intra-cellular localization. Indeed, HOXB9 appeared to be progressively downregulated in epiblast cells and only reappeared after gastrulation had well progressed. The protein was also detected in the primitive endoderm and its derivatives with a distinctive presence in apical vacuoles of mouse visceral endoderm cells.CONCLUSIONS:Together, these results could suggest the existence of unsuspected functions for HOXB9 during early embryonic development in mammals.

Nutrition précoce et métabolisme chez les mamifères. Ecole Chercheurs - Nutrition périnatale "Enjeux et conséquences pour l'alimentation humaine et les pratiques d'élevage"

Seasonal breeding in mammals: From basic science to applications and back. 18. International Congress on Animal Reproduction (ICAR)

National audience; The placenta is a complex, transient organ associated with viviparity, which is located at the interface of the dam and fetus during pregnancy. It is formed after attachment, or implantation, of the blastocyst on the uterine lining and derives from complex cellular and molecular interactions between uterine and embryonic tissues. In mammals, there are many forms of placentation but this organ has the same function in all species: it is responsible for orchestrating materno-fetal exchanges, together with endocrine and immunological functions.; Le placenta est un organe transitoire complexe associé à la viviparité, situé à l’interface entre la mère et le fœtus pendant la grossesse. Il est formé après la fixation (ou l’implantation) du blastocyste à la muqueuse utérine et dérive d’interactions cellulaires et moléculaires complexes entre l’utérus et les tissus embryonnaires. Chez les mammifères, il existe différents types de placentation, mais cet organe exerce la même fonction dans toutes les espèces à savoir des échanges materno-fœtaux, mais aussi des fonctions endocrines et immunologiques.

The neuropeptide kisspeptin and its receptor, KiSS1R, govern the reproductive timeline of mammals by triggering puberty onset and promoting ovulation by stimulating gonadotrophin-releasing hormone (GnRH) secretion. To overcome the drawback of kisspeptin short half-life we designed kisspeptin analogs combining original modifications, triazole peptidomimetic and albumin binding motif, to reduce proteolytic degradation and to slow down renal clearance, respectively. These analogs showed improved in vitro potency and dramatically enhanced pharmacodynamics. When injected intramuscularly into ewes (15 nmol/ewe) primed with a progestogen, the best analog (compound 6, C6) induced synchronized ovulations in both breeding and non-breeding seasons. Ovulations were fertile as demonstrated by the delivery of lambs at term. C6 was also fully active in both female and male mice but was completely inactive in KiSS1R KO mice. Electrophysiological recordings of GnRH neurons from brain slices of GnRH-GFP mice indicated that C6 exerted a direct excitatory action on GnRH neurons. Finally, in prepubertal female mice daily injections (0.3 nmol/mouse) for five days significantly advanced puberty. C6 ability to trigger ovulation and advance puberty demonstrates that kisspeptin analogs may find application in the management of livestock reproduction and opens new possibilities for the treatment of reproductive disorders in humans.