Search results for "biologie"
showing 10 items of 256 documents
Medium-term dynamics of element concentrations in a sparid fish and its isopod parasite after the Prestige oil-spill: Shifting baselines?
2019
Historically, the European Atlantic is probably the most important oil-spill hotspot worldwide. One of the most recent accidents occurred in 2002 when the oil-tanker Prestige sank over the Galician Bank causing two major oil-spills followed by several small leaks until March 2003. This resulted in contamination of virtually all types of marine habitat. Considering that parasites have proved to be good effect and accumulation bioindicators, the present study addresses the medium-term changes in trace element content after the Prestige oil-spill in a model host-parasite system, the bogue, Boops boops (Sparidae) and the isopod Ceratothoa oestroides. To our knowledge, this study is the first to…
Genome-wide promoter methylation analysis in neuroblastoma identifies prognostic methylation biomarkers.
2012
Background: Accurate outcome prediction in neuroblastoma, which is necessary to enable the optimal choice of risk-related therapy, remains a challenge. To improve neuroblastoma patient stratification, this study aimed to identify prognostic tumor DNA methylation biomarkers.Results: To identify genes silenced by promoter methylation, we first applied two independent genome-wide methylation screening methodologies to eight neuroblastoma cell lines. Specifically, we used re-expression profiling upon 5-aza-2'-deoxycytidine (DAC) treatment and massively parallel sequencing after capturing with a methyl-CpG-binding domain (MBD-seq). Putative methylation markers were selected from DAC-upregulated …
Phylogenomic analyses unravel annelid evolution
2011
Annelida, the ringed worms, is a highly diverse animal phylum that includes more than 15,000 described species and constitutes the dominant benthic macrofauna from the intertidal zone down to the deep sea. A robust annelid phylogeny would shape our understanding of animal body-plan evolution and shed light on the bilaterian ground pattern. Traditionally, Annelida has been split into two major groups: Clitellata (earthworms and leeches) and polychaetes (bristle worms), but recent evidence suggests that other taxa that were once considered to be separate phyla (Sipuncula, Echiura and Siboglinidae (also known as Pogonophora)) should be included in Annelida(1-4). However, the deep-level evoluti…
Dietary rescue of altered metabolism gene reveals unexpected [i]Drosophila[/i] mating cues
2015
Running title: Dietary rescue of metabolic mutation and reproduction; To develop and reproduce, animals need long-chain Mono and PolyUnsaturated Fatty Acids (MUFAs; PUFAs). Although some UFAs can be synthesized by the organism, others must be provided by the diet. The gene desat1, involved in Drosophila melanogaster UFA metabolism, is necessary for both larval development and for adult sex pheromone communication. We first characterized desat1 expression in larval tissues. Then, we found that larvae in which desat1 expression was knocked down throughout development died during the larval stages when raised on standard food. By contrast pure MUFAs or PUFAs, but not saturated FAs, added to th…
La fermentation en milieu solide : une innovation de rupture à (re)découvrir
2015
Référence : 201511123537; National audience; Le principal challenge de l’industrie des biotechnologies est lié au développement d’un procédé qui est à la fois économique et efficace en utilisant des matières premières renouvelables pour délivrer des produits à haute valeur ajoutée. La fermentation en milieu solide (FMS) qui met en œuvre des microorganismes sur des matières premières biologiques est un procédé pouvant répondre à ces problématiques.
Femmes de la Préhistoire
2021
Que savons-nous des transformations de leur corps ? Quels rôles avaient-elles dans la famille ? Quels étaient leurs tâches quotidiennes, leurs réalisations techniques et leurs talents artistiques ? De quels pouvoirs disposaient-elles ?De nouvelles découvertes et de nouveaux questionnements rendent enfin visibles ces femmes qui vécurent aux temps lointains de la Préhistoire, de l’aube du Paléolithique jusqu’aux confins de l’âge du fer.En éclairant sous un angle neuf la vie matérielle, familiale, sociale, religieuse des mondes de la Préhistoire, Claudine Cohen ancre la réflexion actuelle sur la différence des sexes et le statut social des femmes jusque dans la profondeur des millénaires.
Escherichia coli cytolethal distending toxin blocks the HeLa cell cycle at the G2/M transition by preventing cdc2 protein kinase dephosphorylation an…
1997
Cytolethal distending toxins (CDT) constitute an emerging heterogeneous family of bacterial toxins whose common biological property is to inhibit the proliferation of cells in culture by blocking their cycle at G2/M phase. In this study, we investigated the molecular mechanisms underlying the block caused by CDT from Escherichia coli on synchronized HeLa cell cultures. To this end, we studied specifically the behavior of the two subunits of the complex that determines entry into mitosis, i.e., cyclin B1, the regulatory unit, and cdc2 protein kinase, the catalytic unit. We thus demonstrate that CDT causes cell accumulation in G2 and not in M, that it does not slow the progression of cells th…
Plasmid localisation of atrazine-degrading genes in newly described Chelatobacter and Arthrobacter strains
2002
Abstract In a previous study, we isolated a collection of atrazine-degrading bacteria from various soils. The aim of this study was to localise the atrazine-degrading genes in these 25 atrazine-degrading strains. In the case of the Gram-negative strains of Chelatobacter heintzii, six to seven plasmids were observed. The atzABC and trzD genes were located on two or three plasmids with variable molecular masses. For the Gram-positive strains of Arthrobacter crystallopoietes, the atzBC genes were located on a single plasmid of 117 kb. The organisation of atrazine-degrading genes seems to be highly variable between the strains studied. We have shown by a specific PCR the occurrence of IS1071-li…
Finding an egg in a haystack: variation in chemical cue use by egg parasitoids of herbivorous insects
2023
Egg parasitoids of herbivorous insects use an interplay of short- and long-range chemical cues emitted by hosts and host plants to find eggs to parasitize. Volatile compounds that attract egg parasitoids can be identified via behavioral assays and used to manipulate parasitoid behavior in the field for biological control of herbivorous pests. However, how and when a particular cue will be used varies over the life of an individual, as well as at and below species level. Future research should expand taxonomic coverage to explore variation in chemical cue use in more natural, dynamic settings. More nuanced understanding of the variability of egg parasitoid host-finding strategies will aid in…
Production of halogenated compounds by Bjerkandera adusta.
1994
International audience; The white-rot fungusBjerkandera adusta produces volatile chlorinated phenyl compounds. The main compounds identified were 3-chloro-4-methoxybenzaldehyde (3-chloro-p-anisaldehyde), 3-chloro-4-methoxybenzyl alcohol (3-chloro-p-anisyl alcohol), 3,5-dichloro-4-methoxybenzaldehyde (3,5-dichloro-p-anisaldehyde), and 3,5-dichloro, 4-methoxybenzyl alcohol (3,5-dichloro-p-anisyl alcohol).p-Anisaldehyde, veratraldehyde and the corresponding alcohols,p-anisyl alcohol and veratryl alcohol were produced simultaneously. Even with a very low concentration of chloride in the medium (<>–5 m), chlorinated aromatic compounds were still observed. Addition of bromide to the culture mediu…