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Les fractures vertébrales sont fréquentes avec la diminution de densité osseuse due à l'âge (Silvermann et al. 1992). Des modèles éléments finis de fracture osseuse ont été présentés dans la littérature afin d'estimer le chargement à rupture de vertèbre unique avec les plateaux vertébraux, mais il n'existe pas de standard international pour ces modèles éléments finis (Crawford et al. 2003, Buckley et al. 2008, Wang et al. 2012). L'objectif de cette étude est d'appliquer un modèle similaire à celui présenté par Keaveny et al. 2020, notamment en termes de propriétés mécaniques élémentaires et de l'appliquer à un jeu de données expérimentales (Wegrzyn et al. 2010).

Abstract We propose a simple biaxial tensional model which is able to reproduce at a qualitative level several aspects of early stages of vertebrate morphogenesis. The model is based on subsequent excitable contractions of an orthoradial and periclinal (radial) set of contracting lines, which generate first the basic embryonic pattern (a motile tube), and second the lateral orifices such as ears, eyes, mouth, gills, etc. An important aspect of the model is the self-arresting character of the process, akin to wound healing. At later stages, the biaxial lines may also work in extension, and this generates a developmental feedback which is quadratic with respect to curvature. Graphic abstract

Nucleoplasmin 2(npm2) is an essential maternal-effect gene that mediates early embryonic events through its function as a histone chaperone that remodels chromatin. Here we report the existence of twonpm2(npm2aandnpm2b) genes in zebrafish. We examined the evolution ofnpm2aandnpm2bin a variety of vertebrates, their potential phylogenetic relationships, and their biological functions using knockout models via the CRISPR/cas9 system. We demonstrated that the twonpm2duplicates exist in a wide range of vertebrates, including sharks, ray-finned fish, amphibians, and sauropsids, whilenpm2awas lost in Coelacanth and mammals, as well as some specific teleost lineages. Using phylogeny and synteny analyses, we traced their origins to the early stages of vertebrate evolution. Our findings suggested thatnpm2aandnpm2bresulted from an ancient local gene duplication, and their functions diverged although key protein domains were conserved. We then investigated their functions by examining their tissue distribution in a wide variety of species and found that they shared ovarian-specific expression, a key feature of maternal-effect genes. We also showed that bothnpm2aandnpm2bare maternally-inherited transcripts in vertebrates. Moreover, we used zebrafish knockouts to demonstrate thatnpm2aandnpm2bplay essential, but distinct, roles in early embryogenesis.npm2afunctions very early during embryogenesis, at or immediately after fertilization, whilenpm2bis involved in processes leading up to or during zygotic genome activation. These novel findings will broaden our knowledge on the evolutionary diversity of maternal-effect genes and underlying mechanisms that contribute to vertebrate reproductive success.Author SummaryThe protein and transcript of thenpm2gene have been previously demonstrated as maternal contributions to embryos of several vertebrates. Recently, twonpm2genes, denoted here asnpm2aandnpm2b, were discovered in zebrafish. This study was conducted to explore the evolutionary origin and changes that occurred that culminated in their current functions. We found that an ancient local duplication of the ancestralnpm2gene created the current two forms, and while most vertebrates retained both genes, notably, mammals and certain species of fish lostnpm2aand, albeit rarely, bothnpm2aandnpm2b. Our functional analyses showed thatnpm2aandnpm2bhave diverse but essential functions during embryogenesis, asnpm2amutants failed to undergo development at the earliest stage whilenpm2bmutants developed, although abnormally, until the zygotic genome activation stage after which their development was arrested followed subsequently by death. Our study is the first to clearly demonstrate the evolution, diversification, and functional analyses of thenpm2genes, which are essential maternal factors that are required for proper embryonic development and survival.

Background Glucose-6-phosphate (G6pc) is a key enzyme involved in the regulation of the glucose homeostasis. The present study aims at revisiting and clarifying the evolutionary history of g6pc genes in vertebrates. Results g6pc duplications happened by successive rounds of whole genome duplication that occurred during vertebrate evolution. g6pc duplicated before or around Osteichthyes/Chondrichthyes radiation, giving rise to g6pca and g6pcb as a consequence of the second vertebrate whole genome duplication. g6pca was lost after this duplication in Sarcopterygii whereas both g6pca and g6pcb then duplicated as a consequence of the teleost-specific whole genome duplication. One g6pca duplicate was lost after this duplication in teleosts. Similarly one g6pcb2 duplicate was lost at least in the ancestor of percomorpha. The analysis of the evolution of spatial expression patterns of g6pc genes in vertebrates showed that all g6pc were mainly expressed in intestine and liver whereas teleost-specific g6pcb2 genes were mainly and surprisingly expressed in brain and heart. g6pcb2b, one gene previously hypothesised to be involved in the glucose intolerant phenotype in trout, was unexpectedly up-regulated (as it was in liver) by carbohydrates in trout telencephalon without showing significant changes in other brain regions. This up-regulation is in striking contrast with expected glucosensing mechanisms suggesting that its positive response to glucose relates to specific unknown processes in this brain area. Conclusions Our results suggested that the fixation and the divergence of g6pc duplicated genes during vertebrates’ evolution may lead to adaptive novelty and probably to the emergence of novel phenotypes related to glucose homeostasis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3727-1) contains supplementary material, which is available to authorized users.

“Alle wahre Naturwissenschaft ist Philosophie und alle wahre Philosophie ist Naturwissenschaft. Alle wahre Wissenschaft aber ist Naturphilosophie”.Ernst Haeckel La publication de l’Origine des Espèces, en 1859, est traditionnellement, et à raison, considérée comme un événement de la plus haute importance dans l’histoire des sciences de la nature, et même de la pensée tout entière. Néanmoins, depuis une vingtaine d’années déjà, le mythe de la “révolution darwinienne” est remis en cause par de ...

“L’étude des gènes dans l’ontogenèse est un champ pour la physiologie du développement. Ce n’est pas pour autant que le généticien sera exclu du traitement de ce problème - il deviendra un embryologiste expérimental et génétique. Après un long séjour qui le détournera parfois du regard de ses collègues biologistes, il reviendra chez lui muni de quelques nouveaux concepts et outils.”Curt Stern La période qui s’étend de la seconde guerre mondiale à la fin des années 1960 correspond sans doute à...

“Alle Gestalten sind ähnlich und keine gleichet der andern,Und so deutet das Chor auf ein geheimes Gesetzt, Auf ein Heiliges Rätsel. O, könnt’ich dir, liebliche Freundin,Überliefern sogleich glücklich das lösende Wort. !Goethe, Zur Metamorphose der Pflanzen. L’abondance chez Haeckel de citations de Goethe et l’hommage rendu par le grand morphologiste au plus célèbre des poètes allemands ne peuvent qu’attirer notre attention sur l’œuvre scientifique de ce dernier, et ce d’autant plus qu’il s’e...

“La philosophie allemande fait entrer les sciences physiques dans cette sphère universelle des idées où les moindres observations comme les plus grands résultats tiennent à l’intérêt de l’ensemble.”Madame de Staël, De l’Allemagne, III, 10. En 1882, dans une communication à l’Association des Naturalistes allemands destinée à rendre hommage à Goethe et à Lamarck, Haeckel énumère les auteurs qu’il considère comme les “précurseurs” de Darwin. Dans cet article, figurent, aux côtés de philosophes p...

De nombreux organismes sont composés de parties répétées, identiques ou modifiées (segments de vers de terre, vertèbres, etc.). Ce mode d’organisation fait l’objet depuis la fin du XVIIIe siècle, de nombreuses interrogations de la part des biologistes : quelle est sa signification anatomique, comment se met-il en place lors de l’embryogenèse, que peut-on en déduire sur l’évolution des espèces, etc. ? Ce livre retrace l’histoire de ces questionnements, des théories et des concepts qu’ils ont suscités depuis deux siècles. Il montre que ce problème de la répétition des parties n’a cessé d’occuper une position centrale, au carrefour de plusieurs disciplines biologiques, et ce jusqu’à nos jours.

“Nous nous tournons maintenant vers un ensemble de faits qui relient génétique, développement et évolution, dans la mesure où ils offrent d’importantes perspectives sur la signification évolutive de changements ponctuels affectant la différenciation embryonnaire précoce.”Richard B. Goldschmidt, The Material Basis of Evolution. Les deux voies issues de la rénovation de la morphologie à la fin du XIXème siècle, c’est-à-dire l’étude de la variation et l’embryologie expérimentale, se rencontrèren...

“À ces mots, plein d’un juste courroux,Il vous prend sa cognée, il vous tranche la bête ;Il fait trois serpents de deux coups,Un tronçon, la queue et la tête.L’insecte sautillant cherche à se réunir,Mais il ne put y parvenir.”La Fontaine, “Le Villageois et le Serpent”. L’une des hypothèses les plus fréquemment invoquées depuis le XIXème siècle, pour rendre compte de la métamérisation des animaux, est celle d’une origine coloniale : au cours de l’évolution, des individus monomériques simples, ...

“Diriez-vous que ce fût la dernière vague ?”Gustav Mahler à Johannes Brahms La question des parties répétées aura donc occupé une position centrale dans l’histoire de la biologie moderne, c’est-à-dire depuis la fin du XVIIIème siècle, à la fois d’un point de vue conceptuel et en termes de “programmes de recherche”. Ce point mérite d’être souligné, car il ne relève apparemment d’aucune nécessité : les faits en cause ressortissent à l’observation quotidienne, du moins dans un premier temps, et ...

“Voir venir les choses est le meilleur moyen de les expliquer”Pierre Turpin Le XVIIIème siècle avait été, pour l’embryologie, le siècle du débat entre les partisans de la préformation et ceux de l’épigenèse, dispute qui fut largement diffusée dans le public intellectuel et donna lieu à des discussions passionnées jusque dans les salons parisiens. Cependant, en dépit de quelques travaux sérieux, dont les plus remarquables furent ceux de Victor Albrecht von Haller (1708-1777), de Lazzaro Spalla...

“The study of segmentation is comparable to study of the Apocalypse. That way leads to madness.”Alfred Sherwood Römer 1874-1973) ( Les deux dernières décennies du XXème siècle ont vu la progression, dans des proportions inédites, de la génétique du développement et plus particulièrement des connaissances portant sur les mécanismes de mise en place et de différenciation des parties répétées. L’application à ces questions des techniques mises au point dans les années 1970, notamment celles du g...

“Haec placuit semel, haec deciens repetita placebit.”Horace, De Arte poetica, 365 Le progrès de la pensée consiste souvent à transformer l'évidence en problématique. Le cas de la répétition des parties des êtres vivants illustre particulièrement bien cet apparent paradoxe. En effet, en quoi le fait que des organismes tels que les insectes ou les annélides sont constitués de segments assemblés, ou que les bras et les jambes d’un être humain sont bâtis selon les mêmes modalités générales, pourr...

“Après tout, même l’antagonisme d’opinions le plus véhément est un avantage au regard du résultat final puisqu’il suscite sans cesse de nouveaux efforts pour étendre le domaine des faits et pour approfondir la compréhension critique”Anton Dohrn Russell qualifie les années 1865 à 1885 de “seconde grande période transcendante pour la morphologie”. De fait, après la publication de l'Origine des espèces puis de la Morphologie générale, la priorité des morphologistes devient la reconstitution des ...

“A fish-like thing appeared among the Annelids one day.It hadn’t any parapods or setae to display.It hadn’t any eyes or jaws or central nervous cordBut it had a lot of gill slits and it had a notochord ! Chorus :It’s a long way from AmphioxusIt’s a long way to us.It’s a long way from AmphioxusTo the meanest human cuss.It’s good-bye fins and gill slits,Wellcome skin and hair.It’s a long way from AmphioxusBut we came from there. [...] My notochord shall grow into a chain of vertebraeAs fins my ...

Background Previously, we have demonstrated that genes involved in ovarian function are highly conserved throughout evolution. In this study, we aimed to document the conservation of genes involved in spermatogenesis from flies to vertebrates and their expression profiles in vertebrates. Results We retrieved 379 Drosophila melanogaster genes that are functionally involved in male reproduction according to their mutant phenotypes and listed their vertebrate orthologs. 83% of the fly genes have at least one vertebrate ortholog for a total of 625 mouse orthologs. This conservation percentage is almost twice as high as the 42% rate for the whole fly genome and is similar to that previously found for genes preferentially expressed in ovaries. Of the 625 mouse orthologs, we selected 68 mouse genes of interest, 42 of which exhibited a predominant relative expression in testes and 26 were their paralogs. These 68 mouse genes exhibited 144 and 60 orthologs in chicken and zebrafish, respectively, gathered in 28 groups of paralogs. Almost two thirds of the chicken orthologs and half of the zebrafish orthologs exhibited a relative expression ≥50% in testis. Finally, our focus on functional in silico data demonstrated that most of these genes were involved in the germ cell process, primarily in structure elaboration/maintenance and in acid nucleic metabolism. Conclusion Our work confirms that the genes involved in germ cell development are highly conserved across evolution in vertebrates and invertebrates and display a high rate of conservation of preferential testicular expression among vertebrates. Among the genes highlighted in this study, three mouse genes (Lrrc46, Pabpc6 and Pkd2l1) have not previously been described in the testes, neither their zebrafish nor chicken orthologs. The phylogenetic approach developed in this study finally allows considering new testicular genes for further fundamental studies in vertebrates, including model species (mouse and zebrafish). Electronic supplementary material The online version of this article (10.1186/s12862-019-1462-8) contains supplementary material, which is available to authorized users.

Oviparous vertebrates produce multiple forms of vitellogenin (Vtg), the major source of yolk nutrients, but little is known about their individual contributions to reproduction and development. This study employed a CRISPR/Cas9 genome editing to assess essentiality and functionality of zebrafish (Danio rerio) type-I and -III Vtgs. The multiple CRISPR approach employed to knock out (KO) all genes encoding type-Ivtgs(vtg1, 4, 5, 6,and7) simultaneously (vtg1-KO), and the type-IIIvtg(vtg3) individually (vtg3-KO). Results of PCR genotyping and sequencing, qPCR, LC-MS/MS and Western blotting showed that onlyvtg6andvtg7escaped Cas9 editing. In fish whose remaining type-Ivtgswere incapacitated (vtg1-KO), and invtg3-KO fish, significant increases in Vtg7 transcript and protein levels occurred in liver and eggs, a heretofore-unknown mechanism of genetic compensation to regulate Vtg homeostasis. Fecundity was more than doubled invtg1-KO females, and fertility was ~halved invtg3-KO females. Substantial mortality was evident invtg3-KO eggs/embryos after only 8 h of incubation and invtg1-KO embryos after 5 d. Hatching rate and timing were markedly impaired invtgmutant embryos and pericardial and yolk sac/abdominal edema and spinal lordosis were evident in the larvae, with feeding and motor activities also being absent invtg1-KO larvae. By late larval stages,vtgmutations were either completely lethal (vtg1-KO) or nearly so (vtg3-KO). These novel findings offer the first experimental evidence that different types of vertebrate Vtg are essential and have disparate requisite functions at different times during both reproduction and development.

International audience; Bone microanatomy appears strongly linked with the ecology of organisms. In amniotes, bone mass increase is a microanatomical specialization often encountered in aquatic taxa performing long dives at shallow depths. Although previous work highlighted the rather generalist inner structure of the vertebrae in snakes utilising different habitats, microanatomical specializations may be expected in aquatic snakes specialised for a single environment. The present description of the vertebral microanatomy of various extinct aquatic snakes belonging to the Nigerophiidae, Palaeophiidae, and Russelophiidae enables to widen the diversity of patterns of vertebral inner structure in aquatic snakes. A large-scale comparative analysis with extant snakes, including numerous semi-aquatic and aquatic forms, and additional extinct taxa, highlights that, even for snakes specialised for a single environment, vertebral microanatomy does not correlate well with the ecology. Thus, it cannot be used as a proxy for ecological inferences in snakes. In addition, the study emphasizes the strong difficulty in characterizing “osteosclerosis” in snake vertebrae. Finally, it points out and discusses the peculiarity of the marine hind-limbed snakes, the only snakes showing pachyosteosclerosis.; La microanatomie osseuse apparaît fortement liée à l’écologie des organismes. Chez les amniotes, l’augmentation de la masse osseuse est une spécialisation microanatomique souvent rencontrée chez les taxons aquatiques qui réalisent de longues plongées à faible profondeur. Si les travaux antérieurs ont mis en évidence le caractère plutôt généraliste de la structure interne des vertèbres chez les serpents qui se meuvent dans divers habitats, on peut s’attendre à observer des spécialisations microanatomiques chez les serpents aquatiques qui se déplacent dans un seul milieu. La présente description de la microanatomie vertébrale de divers serpents aquatiques éteints appartenant aux Nigerophiidae, Palaeophiidae et Russelophiidae permet d’élargir la diversité connue des patrons de structure interne vertébrale des serpents aquatiques. Une large étude comparative avec des serpents actuels, incluant de nombreuses formes semi-aquatiques et aquatiques, ainsi que d’autres taxons éteints, souligne que, même pour les serpents appartenant à un seul milieu, il n’y a pas de correspondance entre la microanatomie vertébrale et l’écologie. La compacité vertébrale ne peut donc pas être utilisée comme un proxy pour réaliser des inférences écologiques chez les serpents. De plus, l’étude souligne la grande difficulté qu’il y a à caractériser l’« ostéosclérose » chez les vertèbres de serpents. Enfin, elle souligne et discute la particularité des serpents marins « à pattes », les seuls à présenter une pachyostéosclérose.

Evolutionary novelties require rewiring of transcriptional networks and/or the evolution of new gene functions. Sex determination (SD), one of the most plastic evolutionary processes, requires such novelties. Studies on the evolution of vertebrate SD revealed that new master SD genes are generally recruited from genes involved in the downstream SD regulatory genetic network. Only a single exception to this rule is currently known in vertebrates: the intriguing case of the salmonid master SD gene (sdY), which arose from duplication of an immune-related gene. This exception immediately posed the question of how a gene outside from the classical sex differentiation cascade could acquire its function as a male SD gene. Here we show that SdY became integrated in the classical vertebrate sex differentiation cascade by interacting with the Forkhead box domain of the female-determining transcription factor, Foxl2. In the presence of Foxl2, SdY is translocated to the nucleus where the SdY:Foxl2 complex prevents activation of the aromatase (cyp19a1a) promoter in cooperation with Nr5a1 (Sf1). Hence, by blocking a positive loop of regulation needed for the synthesis of estrogens in the early differentiating gonad, SdY disrupts a preset female differentiation pathway, consequently allowing testicular differentiation to proceed. These results also suggest that the evolution of unusual vertebrate master sex determination genes recruited from outside the classical pathway like sdY is strongly constrained by their ability to interact with the canonical gonadal differentiation pathway.

Lamp2A à la lumière de l'évolution. Journées d'Animation Scientifique du département Phase (JAS Phase 2018)

The family of forkhead box (Fox) transcription factors regulate gonadogenesis and embryogenesis, but the role of foxr1/foxn5 in reproduction is unknown. Evolution of foxr1 in vertebrates was examined and the gene found to exist in most vertebrates, including mammals, ray-finned fish, amphibians, and sauropsids. By quantitative PCR and RNA-seq, we found that foxr1 had an ovarian-specific expression in zebrafish, a common feature of maternal-effect genes. In addition, it was demonstrated using in situ hybridization that foxr1 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 foxr1 in female reproduction using a zebrafish CRISPR/Cas9 knockout model. It was observed that embryos from the foxr1-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 a dramatically increased level of p21, a cell cycle inhibitor, and reduced rictor, 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 foxr1 is an essential maternal-effect gene and is 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 fitness.

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.

Background Nucleoplasmin 2 (npm2) is an essential maternal-effect gene that mediates early embryonic events through its function as a histone chaperone that remodels chromatin. Recently, two npm2 (npm2a and npm2b) genes have been annotated in zebrafish. Thus, we examined the evolution of npm2a and npm2b in a variety of vertebrates, their potential phylogenetic relationships, and their biological functions using knockout models via the CRISPR/cas9 system. Results We demonstrated that the two npm2 duplicates exist in a wide range of vertebrates, including sharks, ray-finned fish, amphibians, and sauropsids, while npm2a was lost in coelacanth and mammals, as well as some specific teleost lineages. Using phylogeny and synteny analyses, we traced their origins to the early stages of vertebrate evolution. Our findings suggested that npm2a and npm2b resulted from an ancient local gene duplication, and their functions diverged although key protein domains were conserved. We then investigated their functions by examining their tissue distribution in a wide variety of species and found that they shared ovarian-specific expression, a key feature of maternal-effect genes. We also demonstrated that both npm2a and npm2b are maternally-inherited transcripts in vertebrates, and that they play essential, but distinct, roles in early embryogenesis using zebrafish knockout models. Both npm2a and npm2b function early during oogenesis and may play a role in cortical granule function that impact egg activation and fertilization, while npm2b is also involved in early embryogenesis. Conclusion These novel findings will broaden our knowledge on the evolutionary history of maternal-effect genes and underlying mechanisms that contribute to vertebrate reproductive success. In addition, our results demonstrate the existence of a newly described maternal-effect gene, npm2a, that contributes to egg competence, an area that still requires further comprehension. Electronic supplementary material The online version of this article (10.1186/s12862-018-1281-3) contains supplementary material, which is available to authorized users.

Dans un article publié dans le n° 20 de la revue Paleo (Madelaine et al. 2008) nous avons annoncé la découverte d’une série de 11 nouveaux restes humains que nous avons pu rapporter à l’individu n° 1 (Vandermeersch et Trinkaus 1995) de Regourdou mis au jour en septembre 1957. Certains, parmi les plus conséquents (fémur, tibia, fibula), représentaient ou complétaient des régions squelettiques supposées manquantes en raison de gestes funéraires (Bonifay et al. 2007).Dans cette contribution, nous augmentons la représentation squelettique de Regourdou 1 avec de nouvelles pièces. Elles proviennent d’une part de la collection de faune (propriété du Musée national de Préhistoire depuis 2002), de celle de la famille Constant et d’autre part, des collections du Musée d’Art et d’Archéologie de Périgueux. Deux ossements, une diaphyse fémorale gauche et un tibia, proviennent des collections de faune du Musée de site de Regourdou. Mais la morphologie du second ne permet pas de le rapporter à l’Homme de Néandertal.Ces nouvelles découvertes nous permettent donc d’enrichir nos connaissances sur la variabilité anatomique néandertalienne et sur l’histoire de l’occupation du site. Elles valident la présence d’au moins un second adulte moustérien, uniquement représenté par un calcaneus droit. Elles nous autorisent aussi à revenir sur une hypothèse intéressant l’histoire taphonomique du sujet le plus complet (Regourdou 1), hypothèse que nous avions avancée en 2008 et qui apparaît désormais fausse. Enfin, l’origine de l’individu représenté par un tibia de morphologie moderne est inconnue. Il nécessitera une tentative de datation absolue directe. In an article published in Paleo number 20 (Madelaine et al. 2008), we announced the discovery of a new series of 11 human remains that we associated with Regourdou individual number 1 (Vandermeersch and Trinkaus 1995), a specimen first brought to light in September 1957. Some of these new bones, in particular the larger ones (femur, tibia, fibula) represent or make more complete skeletal elements that were presumed to have been missing as the result of funerary acts (Bonifay et al. 2007).In this contribution, we increase the skeletal representation of Regourdou 1 with additional new pieces.These come in part from the site’s faunal collections (property of the Musée national de Préhistoire since 2002), but also from the collections of the Musée d’Art et d’Archéologie de Périgueux. In addition, two pieces: a left femoral diaphysis and the proximal half of a tibia come from the collection of the Constant family, but the morphology of the latter does not appear to be that of a Neandertal.These new discoveries increase our knowledge of Neandertal anatomical variability and the history of the site’s occupation, and also permit us to confirm the presence of at least one second adult Mousterian-associated individual, who is thus far represented solely by a right calcaneus. They also allow us to revisit an interesting hypothesis regarding the taphonomic history of the most complete individual from the site (Regourdou 1), a hypothesis we put forth in 2008 that now turns out to be false. Finally, the origin of the individual represented by the tibia (which evinces modern morphology) is unknown. We will therefore need to obtain an absolute direct date on it.

Open access original paper Source : 10th EPR Workshop on Applications of EPR in Biology and Medicine, 2016 in Krakow, POLAND.; International audience; The mammalian retina contains a high level of polyunsaturated fatty acids, including docosahexaenoic acid (22:6) (DHA), which are highly susceptible to oxidation. It has been shown that one of the products of DHA oxidation-carboxyethylpyrrole (CEP), generated in situ, causes modifications of retinal proteins and induces inflammation response in the outer retina. These contributing factors may play a role in the development of age-related macular degeneration (AMD). It is also possible that some of the lipid oxidation products are photoreactive, and upon irradiation with blue light may generate reactive oxygen species. Therefore, in this work we analysed oxidation-induced changes in photoreactivity of lipids extracted from bovine neural retinas. Lipid composition of bovine neural retinas closely resembles that of human retinas making the bovine tissue a convenient model for studying the photoreactivity and potential phototoxicity of oxidized human retinal lipids. Lipid composition of bovine neural retinas Folch' extracts (BRex) was determined by gas chromatography (GC) and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS) analysis. Liposomes prepared from BRex, equilibrated with air, were oxidized in the dark at 37 A degrees C for up to 400 h. The photoreactivity of BRex at different stages of oxidation was studied by EPR-oximetry and EPR-spin trapping. Photogeneration of singlet oxygen (O-1(2), (1)Delta(g)) by BRex was measured using time-resolved detection of the characteristic phosphorescence at 1270 nm. To establish contribution of lipid components to the analysed photoreactivity of Folch' extract of bovine retinas, a mixture of selected synthetic lipids in percent by weight (w/w %) ratio resembling that of the BRex has been also studied. Folch's extraction of bovine neural retinas was very susceptible to oxidation despite the presence of powerful endogenous antioxidants such as alpha-tocopherol and zeaxanthin. Non-oxidized and oxidized BRex photogenerated singlet oxygen with moderate quantum yield. Blue-light induced generation of superoxide anion by Folch' extract of bovine neural retinas strongly depended on the oxidation time. The observed photoreactivity of the studied extract gradually increased during its in vitro oxidation.

Nucleoplasmin 2 (npm2) is an essential maternal-effect gene that mediates early embryonic events through its function as a histone chaperone that remodels chromatin. Here we report the existence of two npm2 (npm2a and npm2b) genes in zebrafish. We examined the evolution of npm2a and npm2b in a variety of vertebrates, their potential phylogenetic relationships, and their biological functions using knockout models via the CRISPR/cas9 system. We demonstrated that the two npm2 duplicates exist in a wide range of vertebrates, including sharks, ray-finned fish, amphibians, and sauropsids, while npm2a was lost in Coelacanth and mammals, as well as some specific teleost lineages. Using phylogeny and synteny analyses, we traced their origins to the early stages of vertebrate evolution. Our findings suggested that npm2a and npm2b resulted from an ancient local gene duplication, and their functions diverged although key protein domains were conserved. We then investigated their functions by examining their tissue distribution in a wide variety of species and found that they shared ovarian-specific expression, a key feature of maternal-effect genes. We also showed that both npm2a and npm2b are maternally-inherited transcripts in vertebrates. Moreover, we used zebrafish knockouts to demonstrate that npm2a and npm2b play essential, but distinct, roles in early embryogenesis. npm2a functions very early during embryogenesis, at or immediately after fertilization, while npm2b is involved in processes leading up to or during zygotic genome activation. These novel findings will broaden our knowledge on the evolutionary diversity of maternal-effect genes and underlying mechanisms that contribute to vertebrate reproductive success.

Diagnostic imaging of equine thoracolumbar disorders Equine thoracolumbar conditions represent a major cause of poor performance and locomotor disorders in sports and race horses. Advances in diagnostic imaging during the last 15 years allow today to diagnose most equine back lesions in the standing sedated horse. Radiography is the first choice imaging modality due to its high diagnostic performance. Ultrasonography is a complementary modality to further investigate back soft tissues and the caudal lumbar area not evaluable radiographically in the standing horse. Bone scintigraphy is a more complex and expensive technique and is usually dedicated to complicated clinical cases. The most frequent injuries diagnosed using these 3 modalities are kissing spines, osteo-arthrosis of the synovial intervetebral joints, vertebral spondylosis and muscle injuries. Clinical significance of these lesions should be interpreted with care considering the clinical signs exhibited by the horse but also its sports or racing use., Les affections vertébrales thoracolombaires représentent une cause fréquente de baisse de performances et/ou de troubles locomoteurs chez les chevaux de sport et de courses. Le développement des techniques d’imagerie ces 15 dernières années permet aujourd’hui au vétérinaire équin de diagnostiquer un grand nombre de lésions affectant la colonne thoracolombaire sur le cheval debout tranquillisé. La radiographie du dos du cheval constitue la modalité d’imagerie de premier choix par sa capacité diagnostique élevée. L’échographie complète la radiographie dans l’exploration des tissus mous et de la région lombaire caudale, cette dernière n’étant pas accessible par radiographie sur le cheval debout. La scintigraphie, technique plus onéreuse et plus contraignante, est envisagée pour des cas cliniques complexes. Les lésions les plus fréquemment diagnostiquées avec ces techniques d’imagerie sont représentées par les conflits et fractures des processus épineux, les arthroses synoviales intervertébrales, les spondyloses vertébrales et les lésions musculaires. La signification clinique de ces lésions doit être évaluée en considérant les signes cliniques du patient mais également sa discipline sportive., Audigie Fabrice, Coudry Virginie, Jacquet Sandrine, Poupot Marie, Denoix Jean-Marie. Diagnostic par imagerie des lésions de la région thoracolombaire chez le cheval. In: Bulletin de l'Académie Vétérinaire de France tome 166 n°4, 2013. Séance thématique : Production et Santé animales dans les Pays du Sud. pp. 338-344.

International audience; Analgesic external beam radiation therapy is a standard of care for patients with uncomplicated painful bone metastases and/or prevention of bone complications. In case of fracture risk, radiation therapy is performed after surgery in a consolidation of an analgesic purpose and stabilizing osteosynthesis. Radiotherapy is mandatory after vertebroplasty or kyphoplasty. Spinal cord compression - the only emergency in radiation therapy - is indicated postoperatively either exclusively for non surgical indication. Analgesic re-irradiation is possible in the case of insufficient response or recurrent pain after radiotherapy. Metabolic radiation, bisphosphonates or denosumab do not dissuade external radiation therapy for pain relief. Systemic oncological treatments can be suspended with a period of wash out given the risk of radiosensitization or recall phenomenon. Better yet, the intensity modulated radiotherapy and stereotactic radiotherapy can be part of a curative strategy for oligometastatic patients and suggest new treatment prospects.

In vertebrates, one of the first recognizable sex differences in embryos is the onset of meiosis, known to be regulated by retinoic acid (RA) in mammals. We investigated in medaka a possible meiotic function of RA during the embryonic sex determination (SD) period and in mature gonads. We found RA mediated transcriptional activation in germ cells of both sexes much earlier than the SD stage, however, no such activity during the critical stages of SD. In adults, expression of the RA metabolizing enzymes indicates sexually dimorphic RA levels. In testis, RA acts directly in Sertoli, Leydig and pre-meiotic germ cells. In ovaries, RA transcriptional activity is highest in meiotic oocytes. Our results show that RA plays an important role in meiosis induction and gametogenesis in adult medaka but contrary to common expectations, not for initiating the first meiosis in female germ cells at the SD stage.