Excursion Ardèche (13-15 mai 1977)

International audienceLes massifs hercyniens ont été longuement érodés pendant le Permien. Des sédiments gréseux et dolomitiques du Trias se sont ensuite déposés sur une plate-forme uniformisée et peu profonde. Toutefois la monotonie de l'ensemble n'excluait pas l'influence de reliefs sous-marins d'origine hercynienne. Les termes liasiques montrent à la fois une épaisseur réduite et des variations de faciès dues à une plate-forme sous-marine instable. Les influences obéissent d'une part à la direction cévenole (NE-SW) et d'autre part à une direction qui lui est orthogonale. A partir du Callovien les conditions deviennent homogènes dans l'ensemble de la région et paraissent le rester jusque dans le Jurassique terminal

Deep Sequencing of Small RNAs in Tomato for Virus and Viroid Identification and Strain Differentiation

Small RNAs (sRNA), including microRNAs (miRNA) and small interfering RNAs (siRNA), are produced abundantly in plants and animals and function in regulating gene expression or in defense against virus or viroid infection. Analysis of siRNA profiles upon virus infection in plant may allow for virus identification, strain differentiation, and de novo assembly of virus genomes. In the present study, four suspected virus-infected tomato samples collected in the U.S. and Mexico were used for sRNA library construction and deep sequencing. Each library generated between 5–7 million sRNA reads, of which more than 90% were from the tomato genome. Upon in-silico subtraction of the tomato sRNAs, the remaining highly enriched, virus-like siRNA pools were assembled with or without reference virus or viroid genomes. A complete genome was assembled for Potato spindle tuber viroid (PSTVd) using siRNA alone. In addition, a near complete virus genome (98%) also was assembled for Pepino mosaic virus (PepMV). A common mixed infection of two strains of PepMV (EU and US1), which shared 82% of genome nucleotide sequence identity, also could be differentially assembled into their respective genomes. Using de novo assembly, a novel potyvirus with less than 60% overall genome nucleotide sequence identity to other known viruses was discovered and its full genome sequence obtained. Taken together, these data suggest that the sRNA deep sequencing technology will likely become an efficient and powerful generic tool for virus identification in plants and animals

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children

Campagne Biocal: Environnement bathyal actuel et recent aux abords de la Nouvelle Caledonie

A zoological survey of all macrofauna of benthic Invertebrates has been made along the slopes. New taxa of all taxonomic ranks are abundant. High faunal specific diversity and originality is obvious to all taxonomists. It is worth to mention that since the "Challenger" expedition over a century ago, the whole south-western Pacific region has been kept away from the great deep-sea research vessels routes. The study of both the BIOCAL collections and all the others from further cruises around New Caledonia is insured to provide new data to understanding the biogeography and evolution of the deep sea fauna

Production of a polyclonal antiserum against the coat protein of Cucurbit yellow stunting disorder crinivirus expressed in Escherichia coli

International audienc

Pentes et bassins au large de la Nouvelle-Calédonie (Sud-Ouest Pacifique) : morphologie, environnements biosédimentaires, sédimentation

La campagne Biocal s'est déroulée au large de la Nouvelle-Calédonie, à bord du N/O Jean Charcot. Les aspects biologiques, écologiques et sédimentologiques d'une étude des fonds bathyaux et abyssaux y ont été abordés simultanément. Cet article présente les principaux résultats géologiques issus de cette campagne : grands traits morphostructuraux des talus bathyaux, mode de transit des matériaux le long des pentes, origines et mise en place des divers constituants sédimentaires dans le bassin des Loyaut

Grands traits de la sedimentation actuelle et recente sur les pentes et dans les bassins au large de la Nouvelle Caledonie (SW Pacifique): Resultats geologiques de la campagne Biocal

Salient geological results from the Biocal cruise are based on 3.5 khz echosondeur profiles. Slopes morphology is controlled by tectonics and erosion/sedimentation balance. From Thio to Lifou, an uniform basin bottom is depressed southwestward by tectonic subsidence and uneven northeastward by a tectonic ridge (the Levi Ridge). Sedimentation is fed by 5 main sources: Great-Land of New-Caledonia, yielding an important terrigenous flux, reefal barriers surrounding it and raised reefs of Loyalty islands, benthic communities dwelling on slopes and in the basins, plankton and volcanoes of New-Hebridean arc. The development of Quaternary reefal barriers around islands of the new-caledonian archipelago has reduced severely the input from emerged lands and platforms to the basins where the rates of sedimentation are weak

First report of an isolate of Pelargonium zonate spot virus in commercial glasshouse tomato crops in southeastern France

In summer 2000, symptoms similar to Pelargonium zonate spot virus (PZSV) were observed for the first time on tomato plants in southeastern France. The plants were from commercial glasshouse fresh-market crops. Symptoms observed were chlorotic mottling with bright yellow distinct rings on leaves and curved line patterns on stems. Fruit symptoms included chlorotic and necrotic spotting, marked concentric ring patterns, and distortions. Diagnosis was made from symptomatic leaves and fruits by mechanical inoculation on a set of host plants. Local chlorotic and necrotic lesions were observed on Chenopodium amaranticolor, C. quinoa, Cucumis sativus cv. Marketer, Cucumis melo cv. Vedrantais, Phaseolus vulgaris cv. Pinto, Vicia faba cv. D'Aguadulce, Vigna unguiculata cv. Black Eye, and systemic symptoms were observed on Capsicum annuum cvs. Yolo Wonder, Yolo Y, Florida VR2, and Criollo de Morelos 334, Datura stramonium, Lycopersicon esculentum cvs. Momor and Stevens, L. hirsutum (PI 134417 and PI 247087), Nicotiana benthamiana, N. clevelandii, N. tabacum cv. Xanthi nc, Ocimum basilicum cv. Latino, Petunia hybrida cv. Rose du ciel, and Physalis floridana. No reaction was observed on Pisum sativum cv. Douce Provence, Salvia splendens cv. Etna, or Zinnia elegans cv. Liliput. Symptoms on tomato of PZSV, Parietaria mottle virus (PMoV), and Tomato spotted wilt virus (TSWV) are similar, particularly those elicited in fruits. Therefore, the field samples were checked using double-antibody sandwich enzyme-linked immunosorbent assay against antisera of the type-strain of PZSV and tomato strain of PMoV and their homologous antigenes, which were supplied by D. Gallitelli and P. Roggero respectively, and our antiserum of TSWV. Electron microscopy of negatively stained preparations from leaves of tomato and D. stramonium showed that the sap contained very few paraspheric shaped particles, 26 to 29 nm in diameter. Three isolates collected from two different regions (Vaucluse and Bouches du Rhône) showed a very close serological relationship with the Italian type-strain of PZSV and tested negative against antisera of PMoV and TSWV. The French isolates were biologically different from the type-strain, but were similar to the Spanish strain of PZSV because they infected D. stramonium, N. benthamiana, O. basilicum, and V. unguiculata (2). Moreover, in transverse tissue sections, virions were not observed in the nucleus and tubular structures, unlike the Italian isolates, (1) but were present in the cytoplasm and particularly in the mesophyll cells. There are only a few records of the occurrence and distribution of PZSV in Mediterranean countries