New species of Guidus Ivanov, 2006 (Cestoda: Phyllobothriidea) from Bathyraja magellanica (Philippi) from the Patagonian Continental Shelf of Argentina

Specimens representing two new species of Guidus were collected from the Magellan skate (Bathyraja magellanica) in the Patagonian Continental Shelf of Argentina, Southwestern Atlantic Ocean. Guidus francoi sp. n. and Guidus magellanicus sp. n. differ from their congeners by a particular combination of features including type of bothridia, worm length, number of testes, and distribution of vitelline follicles. Guidus francoi sp. n. is distinguished from G. magellanicus sp. n. by having fewer proglottids, fewer testes and a higher ratio between the cirrus sac length and the proglottid width. The microtrix pattern of species of Guidus from the Southwestern Atlantic is described, based on specimens of Guidus francoi sp. n., Guidus magellanicus sp. n., and newly collected specimens of G. argentinense. These three species share the presence of wide aristate gladiate spinitriches on the proximal bothridial surface, narrow gladiate spinitriches on the bothridial rim, and filitriches on the distal bothridial surface. The diagnosis of Guidus is revised to include several features exhibited by the new species (i.e., presence of bothridial indentations and bothridial stalks, distribution of vitelline follicles, and eggs grouped in cocoons). The discovery of G. francoi sp. n. and G. magellanicus sp. n. from B. magellanica increases the number of species of Guidus collected from batoids in the Southwestern Atlantic from one to three. The specificity exhibited by the species herein described reinforces the tight association between Guidus and Bathyraja hosts.Fil: Menoret, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Ivanov, Veronica Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentin

Décodage des réseaux géniques impliqués dans le remodelage cellulaire chez l'embryon de Drosophila melanogaster

La fonction de chacune de nos cellules dépend d'un contrôle précis de son organisation tridimensionnelle. Des surdités génétiques sont par exemple dues à des défauts des extensions cellulaires de l'oreille interne, et la morphologie altérée des cellules cancéreuses favorise l'invasion tumorale. Il est bien établi que les cellules acquièrent progressivement leur forme au cours du développement de l'embryon, mais les mécanismes intimes de la différenciation morphologique restent mal compris. Comment des cellules qui contiennent toutes le même génome peuvent produire des formes aussi différentes ; certains de nos neurones sont 200 000 fois plus longs que nos globules rouges ! Pour aborder ces questions, mes travaux se sont concentrés sur le décryptage des mécanismes de différenciation morphologique de l'épiderme embryonnaire de drosophile. Nous avons entrepris un large effort multidisciplinaire international, impliquant génomique fonctionnelle, bioinformatique, physique et mathématique pour identifier, à l'échelle du génome entier, l'ensemble des effecteurs de la morphogénèse épidermique et leurs éléments de régulation transcriptionnels associés. Nos résultats établissent, pour la première fois à notre connaissance, le répertoire " exhaustif " des gènes directement responsables du remodelage de la forme d'un type cellulaire. Ces données montrent la variété insoupçonnée des différentes fonctions impliquées, incluant régulateurs du cytosquelette, de la matrice extracellulaire, du trafic vésiculaire, de la polarité cellulaire, et de nombreuses protéines au rôle encore inconnu. D'autre part, nous avons établi la cartographie génomique des éléments cis régulateurs, dits CRMs, qui dirigent la transcription des gènes effecteurs de la morphogenèse dans les cellules épidermiques. Par approche transgénique, nous avons démontré la fonctionnalité de plus d'une vingtaine de CRMs. En couplant dissection fonctionnelle in vivo et modélisation computationnelle, nous avons pu commencer à décrypter l'architecture fonctionnelle de ces CRMs, éclairant d'un jour nouveau la logique du contrôle de l'expression du génome. Enfin, nous avons découvert un deuxième programme transcriptionnel qui contrôle la temporalité de la différenciation de l'épiderme. Nous identifions plusieurs centaines de gènes dont l'expression doit être normalement restreinte aux étapes post-embryonnaires du développement. Nous montrons que ces deux programmes indépendants, morphogenèse et différenciation, sont cependant coordonnés par des microprotéines régulatrices, récemment découvertes au laboratoire. Ce travail met en évidence l'intérêt et les limites des nouvelles approches globales d'analyse de l'expression des gènes et démontre la puissance d'une démarche multidisciplinaire en biologie du développement. Il révèle l'étendue des acteurs du contrôle de la morphologie cellulaire et élucide les mécanismes permettant la coordination de leur expression.Cell function depends on a fine control of its morphogenesis. Morphological defects of cancer cell promote cell invasion, and genetic deafness depend on defects of inner ear cells extension. It is well known that cells acquire their shape during development, but mechanisms underlying morphological differentiation are not well described. How cells containing the same genome can finally present such morphological diversity? To answer to this question, we undertook the deciphering of mechanisms implicated in morphological differentiation of the epidermis during drosophila embryonic development. Based on multidisciplinary approaches (functional genomic, bio-informatic, physic and mathematic), we identify at the genome scale the set of epidermal morphogenesis effectors and their respective regulatory elements. For the first time, the "exhaustive" set of genes implicated in shape remodeling of a specific cell type is described, bringing on light an unexpected wide variety of functions, including cytoskeleton, extracellular matrix, vesicular trafficking, planar cell polarity regulators, and unknown proteins. We also describe the genomic mapping of cis-regulatory elements (CRMs) driving transcription of effector genes implicated in epidermal morphogenesis. By transgenic assays we demonstrate in vivo the functionality of about twenty CRMs. Functional dissections associated to in silico modeling permit the deciphering of functional organization of these CRMs, putting forward the logic of the gene expression. Finally we also identify a new transcriptional program controlling the timing of epidermis differentiation. We discover thousands of genes of which expression is restricted to post-embryonic steps of development, and show that the differentiation and morphogenesis programs are finally coordinated by recently identified regulatory micro-proteins. This work brings to light the interest and the limits of new genome wide technics for gene expression analysis, and demonstrates the power of a multidisciplinary approach for developmental biology. It also reveals the extent of cell morphology regulators, and mechanisms implicated in the coordination of their expression

The Petroptimist: Dancing in the Ruins of Fossil Capitalism

Cars have done more to damage our cities than wars.—J. H. Crawford, Carfree Cities Saudi Cars and the Ecological Crisis What can we learn from Riyadh that might reduce our dependency on the car? We know that cars contribute a great deal to the current ecological crisis. This crisis is a consequence of what some authors call the Anthropocene while others, pointing to the specific responsibilities of capitalism, colonialism and imperialism, use the terms Capitalocene, Plantationocene or Secular..

Polar Order in Quantum Paraelectric SrTiO3-16 and SrTiO3-18 at Low Temperature

Optical second-harmonic generation (SHG) in SrTi16O3 (STO16) and SrTi18O3 (STO18) was investigated using the SHG microscope. While no-biased STO16 exhibits weak and almost temperature-independent SHG signals, a marked SHG is observed under the electric field in the quantum paraelectric region. In STO18, strong SHG signals appear spontaneously below 36K. However, neutron and X-ray diffraction analyses indicate that no structural change appears at low temperature in STO18, and STO16 under the electric field. By taking into account the fact that the SHG is sensitive to the local polar-order, the combined studies reveals that the long-range order of polar phase does not develop on the both crystals and is frozen in local regions.Comment: soumis a JPSJ -lettr

Accéléromètre à atomes froids aéroporté pour un test du Principe d'Equivalence

Dans ce mémoire, nous présentons l'étude d'un senseur inertiel à ondes de matière embarqué dans un avion effectuant des vols paraboliques.Une source laser bi-fréquence robuste et compacte permettant de refroidir et d'interroger simultanément des atomes de 87Rb et 39K a été développée. Elle est basée sur des lasers télécom asservis sur un peigne de fréquences optique et doublés en fréquence. L'utilisation de composants optiques fibrés permet de rendre le système intrinsèquement résistant aux vibrations et aux fluctuations thermiques. Le dispositif a été validé en vol par l'obtention d'un double piège magnéto-optique.Nous avons utilisé la source laser pour faire fonctionner un interféromètre à atomes froids de 87Rb dans l'avion. Un accéléromètre mécanique auxiliaire permet d'augmenter la dynamique du capteur atomique et d'enregistrer des franges d'interférences malgré le niveau élevé des fluctuations d'accélération. Le senseur hybride ainsi réalisé a une résolution de 4.10-3 m.s-2.Hz-1/2, environ 100 fois plus faible que le niveau des vibrations dans l'avion.Dans la perspective de réaliser un test du principe d'équivalence en microgravité avec des atomes froids, nous étudions enfin de manière théorique le fonctionnement d'un interféromètre différentiel et nous intéressons à l'influence de certains effets systématiques.In this thesis, we report on the study of a matter-wave inertial sensor, operated in an airplane carrying out parabolic flights.We have developped a compact and robust dual-wavelength laser source to cool and interrogate 87Rb and 39K atoms. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. The use of fibered optical components makes the setup intrinsically immune to vibrations and thermal fluctuations. The laser source was validated in flight by obtaining a double-species magneto-optical trap.We have used the source to carry out airborne measurements with an atom interferometer operating with cold 87Rb atoms. An auxiliary mechanical accelerometer makes it possible to increase the atomic sensor's dynamic range, and to record interference fringes despite the high level of acceleration fluctuations. This hybrid sensor has a resolution of 4.10-3 m.s-2.Hz-1/2, which is approximately 100 times lower than the typical vibration level in the plane.In the perspective of testing the equivalence principle with cold atoms in microgravity, we finally theoretically study the operation of a differential interferometer and investigate the influence of some systematic effects.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Tapeworms (Platyhelminthes, Cestoda) from marine chondrichthyans of the Southwestern Atlantic Ocean, and the sub-Antarctic and Antarctic islands: a checklist

A parasite-host list of cestodes parasitizing chondrichthyans in the Southwest Atlantic off Argentina and surrounding waters of Antarctica is compiled based on the available literature. The list is based on published descriptions and redescriptions of species, and newly collected worms during the current study. A total of 57 valid species belonging to 28 genera of the orders Cathetocephalidea, Diphyllidea, Gyrocotylidea, Lecanicephalidea, Onchoproteocephalidea, Phyllobothriidea, Rhinebothriidea, “Tetraphyllidea”, and Trypanorhyncha is listed. Information on hosts, localities, specimens in collections and comments on tapeworms are also included. A host-parasite list including chimaeras (1 order, 1 genus), batoids (4 orders, 10 genera), and sharks (3 orders, 5 genera) is provided. Tapeworm diversity, distribution range, and host associations are discussed. The cestodes orders Phyllobothriidea and Rhinebothriidea exhibit the highest species richness, with 13 and 12 species, respectively. Onchoproteocephalideans and rhinebothriideans have the broadest geographic distribution in the study area. Regarding hosts, arhynchobatid skates are the group most frequently associated with cestodes. However, further collecting efforts are necessary to understand whether this data reflect the real diversity and host association of these parasites or is a result of a bias in sampling

Etude expérimentale et théorique du mécanisme d'excitation aéroacoustique des césures automobiles.

Un travail expérimental et théorique sur les césures, petites cavités de faible longueur suivant l'axe de l'écoulement et situées au niveau de l'interstice entre deux portes ou entre une porte et la caisse du véhicule, est présenté ici. Bien que peu étudiées dans la littérature, les césures constituent une source d'excitation aéroacoustique non négligeable sur un véhicule : le niveau de fluctuation de pression au fond de celle-ci est supérieur dans certains cas à celui créé par la couche limite au-dessus. Le but de cette étude est de comprendre l'origine de ce mécanisme d'amplification. Des mesures de pression instationnaire en paroi et des mesures du champ de vitesse par fil chaud deux composantes ont été réalisées sur un véhicule de série, dans la soufflerie aéroacoustique S2A de Montigny le Bretonneux. Elles ont permis de montrer que les fluctuations de pression de la couche limite, de nature acoustique et turbulente, sont transformées en fluctuations de pression acoustique à l'intérieur de la césure par un mécanisme de filtrage linéaire qui se décrit par le formalisme des fonctions de transfert

3-[2-(3-Methyl­quinoxalin-2-yl­oxy)eth­yl]-1,3-oxazolidin-2-one

Two isomers were isolated during the reaction between 3-methyl­quinoxalin-2-one and bis­(2-chloro­ethyl)amine hydro­chloride. The crystal structure of one isomer has already been reported [Caleb, Bouhfid, Essassi & El Ammari (2009). Acta Cryst. E65, o2024–o2025], while that of the second isomer is the subject of this work. The title compound, C14H15N3O3, has a new structure containing oxazolidine and quinoxaline rings linked by an eth­oxy group. The main difference between the two isomers is the position of the oxazolidine group with respect to the quinoxaline system. The dihedral angle between the fused planar rings and the oxazolidin-2-one ring is 41.63 (8)° in the title mol­ecule

IL-36 receptor is expressed by human blood and intestinal T lymphocytes and is dose–dependently activated via IL-36β and induces CD4+ lymphocyte proliferation

We show that IL-36R is expressed by T (CD4+ and CD8+) and B (CD19+) lymphocytes in human blood and also by CD4+ T lymphocytes in the intestinal lamina propria. IL-36R protein was mostly stored in the cytoplasm of CD4 lymphocytes and B cells, during steady state conditions and the greatest expression of IL-36R mRNA was measured in CD4+ (T helper) lymphocytes. IL-36 β, which functions via IL-36R induced rapid and significant (P < 0.05) proliferation of CD4+ lymphocytes, within 48 h. IL-36R expression was also maintained on the surface of circulating CD4+ lymphocytes which enter the intestinal lamina propria. In conclusion our study is the first to show that (1) all human blood lymphocytes express IL-36R; (2) IL-36R expression is maintained by circulating CD4+ lymphocytes which enter the intestinal lamina propria and (3) IL-36R/IL-36 β induces rapid CD4 lymphocyte proliferation. The possible significance of these results in the context of human disease is discussed

T cell sensitivity to TGF-β is required for the effector function but not the generation of splenic CD8+ regulatory T cells induced via the injection of antigen into the anterior chamber

The introduction of antigen into the anterior chamber (AC) of the eye induces the production of antigen-specific splenic CD8+ regulatory T cells (AC-SPL cells) that suppress a delayed-type hypersensitivity (DTH) reaction in immunized mice. Because the generation of these regulatory T cells is also induced by exposure to transforming growth factor (TGF)-β and antigen or F4/80+ cells exposed to TGF-β and antigen in vitro, we investigated (i) whether these cells are produced in dominant negative receptor for transforming growth factor β receptor type II (dnTGFβRII) or Cbl-b−/− mice whose T cells are resistant to TGF-β, (ii) whether DTH is suppressed by wild type (WT) CD8+ AC-SPL cells in Cbl-b−/− and dnTGFβRII mice and (iii) the effect of antibodies to TGF-β on the suppression of DTH by CD8+ AC-SPL cells. DnTGFβRII immunized and Cbl-b−/− mice produced splenic CD8+ regulatory cells after the intracameral injection of antigen and immunization. The suppression of a DTH reaction by CD8+ AC-SPL cells in WT mice was blocked by the local inclusion of antibodies to TGF-β when WT splenic CD8+ AC-SPL cells were injected into the DTH reaction site. Moreover, the DTH reaction in immunized dnTGFβRII and Cbl-b−/− mice was not suppressed by the transfer of WT CD8+ AC-SPL cells to the site challenged with antigen. In aggregate, these observations suggest that T cell sensitivity to TGF-β is not an obligate requirement for the in vivo induction of CD8+ AC-SPL T cells but the suppression of an in vivo DTH reaction by CD8+ AC-SPL cells is dependent on TGF-β