Use of intraoral three-dimensional images for the identification of dental morphological traits related to ancestry estimation

Victim identification through dental features is one of the main objectives of forensic dentistry. In circumstances where information regarding antemortem dental records is missing, reconstruction of a biological profile can be useful as a first step toward personal identification. This reconstructive method provides valuable information, namely regarding the individual's ancestry, through the detection and degree of expression of dental morphological traits, which may help to restrict the number of candidates for identification. Technological advances allowed the development of alternative methods for dental evaluation, that complement or substitute those already in use in clinical practice. Among these, intraoral three-dimensional (3D) images are increasingly used in dentistry, as they have a high level of accuracy and are easy to obtain and store. However, a fundamental question regarding forensic dentistry is whether they allow recognition and analysis of dental morphological traits in detail, namely those related to ancestry. In this study, we evaluated 20 teeth morphological features using intraoral 3D imaging from 77 individuals from Northern Portugal. Our results showed that it was possible to identify and classify a large part of the main morphological traits used in the estimation of ancestry. As these 3D images present sufficient morphological detail to be classified, we believe that future applications of this technique can be expected in forensic dentistry

A Highly Conserved Poc1 Protein Characterized in Embryos of the Hydrozoan Clytia hemisphaerica: Localization and Functional Studies

Poc1 (Protein of Centriole 1) proteins are highly conserved WD40 domain-containing centriole components, well characterized in the alga Chlamydomonas, the ciliated protazoan Tetrahymena, the insect Drosophila and in vertebrate cells including Xenopus and zebrafish embryos. Functions and localizations related to the centriole and ciliary axoneme have been demonstrated for Poc1 in a range of species. The vertebrate Poc1 protein has also been reported to show an additional association with mitochondria, including enrichment in the specialized “germ plasm” region of Xenopus oocytes. We have identified and characterized a highly conserved Poc1 protein in the cnidarian Clytia hemisphaerica. Clytia Poc1 mRNA was found to be strongly expressed in eggs and early embryos, showing a punctate perinuclear localization in young oocytes. Fluorescence-tagged Poc1 proteins expressed in developing embryos showed strong localization to centrioles, including basal bodies. Anti-human Poc1 antibodies decorated mitochondria in Clytia, as reported in human cells, but failed to recognise endogenous or fluorescent-tagged Clytia Poc1. Injection of specific morpholino oligonucleotides into Clytia eggs prior to fertilization to repress Poc1 mRNA translation interfered with cell division from the blastula stage, likely corresponding to when neosynthesis normally takes over from maternally supplied protein. Cell cycle lengthening and arrest were observed, phenotypes consistent with an impaired centriolar biogenesis or function. The specificity of the defects could be demonstrated by injection of synthetic Poc1 mRNA, which restored normal development. We conclude that in Clytia embryos, Poc1 has an essentially centriolar localization and function

Centrioles: active players or passengers during mitosis?

Centrioles are cylinders made of nine microtubule (MT) triplets present in many eukaryotes. Early studies, where centrosomes were seen at the poles of the mitotic spindle led to their coining as “the organ for cell division”. However, a variety of subsequent observational and functional studies showed that centrosomes might not always be essential for mitosis. Here we review the arguments in this debate. We describe the centriole structure and its distribution in the eukaryotic tree of life and clarify its role in the organization of the centrosome and cilia, with an historical perspective. An important aspect of the debate addressed in this review is how centrioles are inherited and the role of the spindle in this process. In particular, germline inheritance of centrosomes, such as their de novo formation in parthenogenetic species, poses many interesting questions. We finish by discussing the most likely functions of centrioles and laying out new research avenues

ACTIVATION LOCALISEE DU MPF DANS LES UFS DE XENOPE

DURANT LE DEVELOPPEMENT PRECOCE, LES COMPOSANTS MATERNELS SONT PLACES ASYMETRIQUEMENT DANS CHAQUE CELLULE. CETTE ASYMETRIE A DES CONSEQUENCES IMPORTANTES POUR L'ORGANISATION DE L'EMBRYON. LA LOCALISATION DES COMPOSANTS MATERNELS EST DEPENDANTE DE L'ORGANISATION DU CYTOSQUELETTE CORTICAL, QUI SUBIT D'AILLEURS D'IMPORTANTS REMANIEMENTS A CHAQUE MITOSE ET A CHAQUE CLIVAGE. L'INFLUENCE DE LA PROGRESSION DU CYCLE CELLULAIRE SUR LES REORGANISATIONS CYTOSQUELETTIQUES RESTE POURTANT UN DOMAINE PEU EXPLORE. CETTE THESE CONCERNE LA RELOCALISATION CYTOPLASMIQUE QUI ACCOMPAGNE L'ACTIVATION DU REGULATEUR MITOTIQUE UNIVERSEL, LE MPF (MATURATION/ M-PHASE PROMOTING FACTOR), DANS L'UF DE XENOPE. DANS UN PREMIER TEMPS, J'AI ETUDIE LA RELATION ENTRE L'ACTIVATION DU MPF ET LES DEUX VAGUES DE CONTRACTION DE SURFACE (SCW : SURFACE CONTRACTION WAVES). CES VAGUES SE PROPAGENT DU POLE ANIMAL DE L'UF JUSQU'AU POLE VEGETATIF A CHAQUE CYCLE MITOTIQUE PRECOCE. CES SCW SONT IMPLIQUEES DANS LA CONCENTRATION PROGRESSIVE DES ILOTS DE PLASMES GERMINATIFS DANS LA REGION DU POLE VEGETATIF. J'AI PU DEMONTRER PAR ANALYSES DES FRAGMENTS D'UF QUE L'ACTIVATION DU MPF A L'ENTREE EN MITOSE N'EST PAS HOMOGENE DANS LE CYTOPLASME MAIS COMMENCE DANS L'HEMISPHERE ANIMAL. DE PLUS, DES EXPERIENCES DE LIGATION ONT MONTRE QUE L'ACTIVATION DU MPF SE PROPAGE DANS TOUT L'UF, PROBABLEMENT GRACE A UNE BOUCLE POST-TRANSCRIPTIONNELLE AUTO-ACTIVATRICE. LA PREMIERE SCW ACCOMPAGNE TOUT D'ABORD L'ACTIVATION PROGRESSIVE DU MPF, PUIS LA DEUXIEME SCW SUIT UNE INACTIVATION PROGRESSIVE DU MPF. CES CORRELATIONS SPATIO-TEMPORELLES SUGGERENT QUE LES SCW SONT DES REORGANISATIONS CORTICALES PROVOQUEES LOCALEMENT PAR L'ACTIVATION PUIS L'INACTIVATION DU MPF. EN ACCORD AVEC CETTE IDEE, LA MICROINJECTION DU MPF DANS LES REGIONS VEGETATIVE ET EQUATORIALE A PROVOQUE DES VAGUES ECTOPIQUES DE REORGANISATION. LA DEUXIEME PARTIE DE MON TRAVAIL A ETE DE MONTRER QUE L'ACTIVATION LOCALE DU MPF DANS L'HEMISPHERE ANIMALE A LA PREMIERE MITOSE POUVAIT ETRE EXPLIQUEE PARTIELLEMENT PAR LA STIMULATION DE L'ACTIVATION DU MPF PAR L'ASTER SPERMATIQUE ET PAR LE NOYAU ZYGOTIQUE. MPF EST GENERALEMENT CONSIDERE COMME ETANT REGULE UNIQUEMENT PAR DES FACTEURS CYTOPLASMIQUES DANS CES CELLULES, PUISQUE NI LE NOYAU, NI L'ASTER MICROTUBULAIRE NE SONT NECESSAIRES POUR L'ACTIVATION DU MPF. POURTANT, LES LIGATIONS DESTINEES A SEPARER LES NOYAUX DES CENTROSOMES DANS DIFFERENTS FRAGMENTS D'UF ET LES EXPERIENCES IN VITRO A PARTIR D'EXTRAITS CYTOPLASMIQUES CYCLANTS ONT MONTRE QUE CES DEUX STRUCTURES STIMULAIENT L'ACTIVATION DU MPF. DE PLUS, LA MICROINJECTION DE CENTRIOLES ISOLES DANS LES UFS ENUCLEES PROVOQUE DES SCW PRECOCES (UTILISEES COMME INDICATEURS DE L'ACTIVATION DU MPF). IL APPARAIT DONC QUE LES COMPOSANTS STRUCTURAUX QUE SONT LE NOYAU ET L'ASTER SPERMATIQUE PARTICIPENT AU CONTROLE DE L'ENTREE EN MITOSE. ILS AGISSENT INDEPENDAMMENT MAIS ILS COOPERENT POUR LOCALISER L'ACTIVATION DU MPF. CETTE ACTIVATION LOCALISEE DUE AU NOYAU ET A L'ASTER POURRAIT ETRE UN MECANISME GENERAL DESTINE A CREER OU A RENFORCER LES ASYMETRIES DURANT LE DEVELOPPEMENT PRECOCE CHEZ DE NOMBREUSES ESPECES.PARIS-BIUSJ-Thèses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF