The prevalence of badnaviruses in West African yams (Dioscorea cayenensis-rotundata) and evidence of endogenous pararetrovirus sequences in their genomes

Yam (Dioscorea spp.) is an important vegetatively-propagated staple crop in West Africa. Viruses are pervasive in yam worldwide, decreasing growth and yield, as well as hindering the international movement of germplasm. Badnaviruses have been reported to be the most prevalent in yam, and genomes of some other badnaviruses are known to be integrated in their host plant species. However, it was not clear if a similar scenario occurs in Dioscorea yam. This study was conducted to verify the prevalence of badnaviruses, and determine if badnavirus genomes are integrated in the yam genome

Les Chaetognathes de Nosy Bé: Description de Sagitta galerita sp. n

Sagitta galerita sp. n. a été capturée dans les eaux superficielles du secteur de Nosy Bé (Madagascar, océan Indien). Proche de S. robusta Doncaster, avec laquelle elle a été confondue, elle s’en distingue surtout par la structure des vésicules séminales dont la tête, sans disque adhésif, est partiellement recouverte par un épaississement tégumentaire, et ses nageoires postérieures, entièrement garnies de rayons, insérées pour la plus grande part sur le segment caudal. Elle est également apparentée à la forme peu connue S. hispida americana ( Tokioka, 1959). A Nosy Bé, elle caractérise la zone néritique externe pendant les périodes de fortes salinités

L\u27anatomie du tube digestif dans la phylog\ue9nie et la syst\ue9matique des Chaetognathes

Volume: 42Start Page: 549End Page: 56

Évolution annuelle en profondeur du zooplancton gélatineux au large de Villefranche-sur-Mer

Goy Jacqueline, Dallot Serge. Évolution annuelle en profondeur du zooplancton gélatineux au large de Villefranche-sur-Mer. In: Le milieu littoral. Actes du 124e Congrès national des sociétés historiques et scientifiques, « Milieu littoral et estuaires », Nantes, 1999. Paris : Editions du CTHS, 2002. pp. 95-108. (Actes du Congrès national des sociétés savantes, 124

Metazoan Meiobenthos temporal fluctuations in the deep NW Mediterranean Sea (DYFAMED-BENTHOS 1993-1995). Contribution of spatial variability and disturbance

Time-series surveys to resolve metazoan meiofauna abundance fluctuations in the deep sea are scarce. Between January 1993 and October 1995, surface sediment was collected with a multicorer at an average sampling frequency of 1.3 months at the DYFAMED-BENTHOS station (43 degrees 24.62' N-7 degrees 51.68' E; 2347 m depth) in the NW Mediterranean. Total metazoan meiofauna abundance in the 170 samples collected over the three-year period ranged from 133 to 770 ind. 10 cm(-2) (mean 380 ind. 10 cm(-2)). The community comprised on the average similar to 89% nematodes, 4.7% copepods, 4.3% nauplii, 1.1% annelids and 0.5% least common taxa pooled (Others). Variability in organism abundances was analysed at three spatial- (cm, 10-cm, 100-m) and two temporal (dates, years) scales, using coefficients of dispersion, nested ANOVAs and autocorrelation statistics. All the meiobenthic groups except the annelids exhibited aggregation at the centimetre scale. The 5 sources of variation together explained similar to 95% of the variability in the nematode abundances. They explained 65% of the variability in the abundances of nauplii and <55% in that of copepods, annelids and Others. Variability at the decimetre scale (i.e. 10-cm scale) was significant only for the copepods and the nauplii. Variability at the scale of the coring site (i.e. hectometre= 100-m scale) was low. The temporal factor (dates and years together) contributed 58% to the variability in the nematode abundances. Time contributed 33%, 25% and 8% to the variability in the numbers of nauplii, Others, and annelids, respectively. Nematode abundances varied equally among dates and years, but seasonal variation dominated in the case of nauplii, while interannual variation dominated in the case of Others. Abundances of annelids (i.e. macrofauna juveniles) varied significantly among years, and temporal variation was not significant in the copepods. Active dispersal (emergence) would explain the decimetre-scale variability for the copepods and the nauplii, as well as the absence of observed temporal fluctuations in the copepods. The high-frequency long-term DYFAMED-BENTHOS time series produced clear evidence of statistically significant seasonal and interannual fluctuations in deep-sea metazoan meiofauna abundances at the major taxon level. The temporal fluctuations were not overridden by local spatial patterns. While the driving factor for the faunal increases could be the recurring sea-surface derived food pulses, a moderate physical disturbance (sediment deposition) that occurred at the end of 1994, generated strong short- and long-term reactions in the different meiobenthic groups, and thereby largely influenced the food-induced interannual abundance patterns. A high sampling frequency combined to specific features of the sampling site certainly contributed to the clarity of the quantitative faunal responses observed in this survey. (C) 2014 Elsevier Ltd. All rights reserved

MESOZOOPLANKTON ABUNDANCE AND BIOMASS RELATED TO HYDROLOGICAL STRUCTURE ALONG THE ALGERIAN COASTS (SW MEDITERRANEAN SEA)

Along the Algerian coasts, studies on the effect of the Atlantic water current on the ecology, biomass, and abundance of mesozooplankton were scarce during the last decade. Following several multidisciplinary oceanographic cruises (1990, 1998, 2000, 2004, 2008), the Algerian basin has been shown to be characterized by the presence of a frontal area (surface chlorophyll a concentrations more than 1 mg.m(-3)). This front is situated between 1 degrees and 4 degrees E. It results from the contact between the Modified Atlantic Water and the Mediterranean Surface Water. The front is marked by a sharp horizontal salinity gradient between the inshore (S = 36.6) and the offshore (S = 36.8) waters. MAW and MSW ecosystems are known for their oligotrophy (surface chlorophyll a concentrations less than 1 mg.m(-3)). Small species like Paracalanus porous and Clausocalanus sp. dominate the community in the frontal zone. In the offshore Mediterranean Surface Water zone, carnivores like Oithona, Oncaea, and Pontella dominate both omnivores and herbivores (Temora stylifera Euterspina acutifrous), predation appears to be more often a characteristic of oligotrophic systems. The species cited above appeared as promising populations for studying the hydrological features and their effects on mesozoplankton communities

Observations hydrologiques à une station côtière méditerranéenne. Point B. Rade de Villefranche-sur-Mer 43°41'10''N - 7°19'00''E

This paper presents the results of hydrological measurements obtained at standard depths (0, 10, 20, 30, 50, et 75 meters), at the B point in the bay of Villefranche-sur-Mer (Mediterranean Sea : 43°41'10"N, 7°19'00"E). These 1168 observations were made from May 1957 to December 1988. The salinity was converted to the pratical salinity scale 1978, and the density was recalculated using the international equation of state of seawater 1980 (UNESCO, 1983). The data (temperature, salinity, sigma-t), are presented in chronogical order of sampling. A summary table gives, for all three variables, the maximum and minimum value, the mean and standard deviation, for each month and each depth.Ce recueil présente les données hydrologiques obtenues aux profondeurs standard (0, 10, 20, 30, 50, et 75 mètres), au point B de la rade de Villefranche-sur-Mer (Méditerranée : 43°41'10"N,  7°19’00"E). Les stations, au nombre de 1168, ont été effectuées entre mai 1957 et décembre 1988. Les salinités ont été, autant que possible, converties dans l'échelle pratique de salinité de 1978, et les masses volumiques ont toutes été recalculées conformément à l'équation de l'eau de mer 1980 (UNESCO, 1983). Les données (température, salinité, sigma-t), sont présentées dans l'ordre chronologique des stations. Un récapitulatif a été fait, qui donne par mois et par profondeur, pour chacune des trois variables, la valeur maximale et minimale, la moyenne et l'écart type

Field study of the chemical characterization of the upper ocean surface using various samplers

International audienc

Metagenomics approaches based on Virion-Associated Nucleic Acids (VANA): an innovative tool for assessing without a priori viral diversity of plants

Equipe BGPI : 6 / 7International audienceThis chapter describes an efficient approach that combines quality and yield extraction of viral nucleic acids from plants containing high levels of secondary metabolites and a sequence-independent amplification procedure for both the inventory of known plant viruses and the discovery of unknown ones. This approach turns out to be a useful tool for assessing the virome (the genome of all the viruses that inhabit a particular organism) of plants of interest. We here show that this approach enables the identification of a novel Potyvirus member within a single plant already known to be infected by two other Potyvirus species