Search results for "Life"
showing 10 items of 24622 documents
Ancient DNA evidence for the loss of a highly divergent brown bear clade during historical times
2008
The genetic diversity of present-day brown bears (Ursus arctos) has been extensively studied over the years and appears to be geographically structured into five main clades. The question of the past diversity of the species has been recently addressed by ancient DNA studies that concluded to a relative genetic stability over the last 35,000 years. However, the post-last glacial maximum genetic diversity of the species still remains poorly documented, notably in the Old World. Here, we analyse Atlas brown bears, which became extinct during the Holocene period. A divergent brown bear mitochondrial DNA lineage not present in any of the previously studied modern or ancient bear samples was unc…
Effects of habitat fragmentation on the genetic structure of the monophagous butterfly Polyommatus coridon along its northern range margin
2004
Population genetic patterns of species at their range margin have important implications for species conservation. We performed allozyme electrophoresis of 19 loci to investigate patterns of the genetic structure of 17 populations (538 individuals) of the butterfly Polyommatus coridon, a monophagous habitat specialist with a patchy distribution. The butterfly and its larval food plant Hippocrepis comosa reach their northern distribution margin in the study region (southern Lower Saxony, Germany). Butterfly population size increased with host plant population size. The genetic differentiation between populations was low but significant (FST = 0.013). No isolation-by-distance was found. Hiera…
Purification, characterization and influence on membrane properties of the plant-specific sphingolipids GIPC
2020
AbstractThe plant plasma membrane (PM) is an essential barrier between the cell and the external environment. The PM is crucial for signal perception and transmission. It consists of an asymmetrical lipid bilayer made up of three different lipid classes: sphingolipids, sterols and phospholipids. The most abundant sphingolipids in the plant PM are the Glycosyl Inositol Phosphoryl Ceramides (GIPCs), representing up to 40% of total sphingolipids, assumed to be almost exclusively in the outer leaflet of the PM. In this study, we investigated the structure of GIPCs and their role in membrane organization. Since GIPCs are not commercially available, we developed a protocol to extract and isolate …
Tooth tales told by dental diet proxies: An alpine community of sympatric ruminants as a model to decipher the ecology of fossil fauna
2021
Abstract Paleobiologists tend to use dietary information as an ecological indicator because diet is a fundamental link between an organism and its environment. However, the ecological information from fossilized hard tissues is often difficult to interpret, because links between environment, diet, and hard tissue biology are insufficiently studied in modern communities. To address this dilemma, we investigated dietary proxies commonly used by paleobiologists in a 4-ruminant community from the French Alps. Dental microwear texture analyses are applied to 82 specimens of roe deer, red deer, chamois, and mouflons. Intra-tooth serial enamel stable carbon and oxygen isotope analyses of the struc…
Shell repair in the clam Ruditapes philippinarum, affected by the Brown Ring Disease (BRD): a biochemical and serological study.
2009
AbstractFor more than two decades, the edible clam Ruditapes philippinarum has been affected by the Brown Ring Disease (BRD), a bacterial infection characterized by the formation of a brown organic deposit in the internal side of the valves. Although this infection is often lethal, in some cases specimens can overcome it by remineralizing over the organic deposit. The goal of the present study is to compare biochemically and immunologically the shell matrices of repaired and healthy zones. Our data suggest that the repair zones exhibit certain variability, which would be the direct consequence of a modification of the secretory regime of calcifying tissues responsible of the repair process.
Body shape differentiation at global and local geographic scales in the invasive cichlid Oreochromis mossambicus
2012
The Mozambique tilapia Oreochromis mossambicus (Teleostei, Cichlidae) has been transplanted worldwide during the 20th century, and now belongs to the list of the most invasive species. Using a geometric morphometric approach, we describe body shape differentiation among 15 populations from native (Mozambique) and invaded (New Caledonia and Guadeloupe) ranges. A dominant phylogeographic signal is detected, despite the broad range of environmental conditions at the local scale. This result suggests that phylogeographic background rather than phenotypic plasticity responding to environmental variation constitutes the main factor correlated with shape divergence. This could result from successi…
Evolutionary history of two allopatric Terricola species (Arvicolinae, Rodentia) from molecular, morphological, and palaeontological data
2008
To investigate the phylogenetic and phylogeographical relationships of arvicolines, we use several Western European ground voles. More particularly, our study is focused on Microtus (Terricola) savii and M. (T.) pyrenaicus. These two allopatric species are usually considered as having originated from the same ancestor, possibly M. (T.) mariaclaudiae. We propose molecular and morphological approaches: nucleotidic data from the mitochondrial cytochrome b and 12S rRNA genes and global morphological analyses from the first lower molar. Four other Terricola species (multiplex, lusitanicus, duodecimcostatus, subterraneus) were added to the data set for both analyses, and two other vole species (C…
Effects of peroxidizing herbicides on protoporphyrin IX levels in non-chlorophyllous soybean cell culture
1990
Abstract The mode of action of 16 peroxidizing herbicides belonging to four different families (diphenyl ethers, oxadiazon, pyridine derivatives, and pyrazole derivatives) has been studied in nonchlorophyllous soybean cell cultures. Whenever possible, we have compared active and inactive compounds. Phytotoxic effects were estimated on the basis of growth inhibition, either in the dark or in the light. Protoporphyrin IX accumulations were estimated in dark-treated samples, using a simple methodology. In all cases, we have found a positive correlation between cellular damages and protoporphyrin IX accumulations. The results provide further evidences in favor of the light-dependent activity of…
Why no tetraploid cultivar of foxtail millet?
2004
Autotetraploid material was induced by colchicine treatment of a pure line of foxtail millet and an interspecific hybrid between foxtail millet and giant green foxtail. Compared with diploid material, tetraploids were smaller, flowered later, and had a two-fold reduced fertility (number of grain per cm of spike). Grain weight increased by 20% with polyploidy, but total grain yield decreased by 46%. This work illustrates the difficulty of breeding polyploid lines of foxtail millet that are of agronomic use.
Evaluation of fungicides and sterilants for potential application in the management of Fusarium wilt of banana
2007
Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; Fusarium wilt is considered one of the most important diseases of bananas. The disease can only be managed by using resistant cultivars and by preventing its introduction into new fields. The objectives of this study were to evaluate newly available fungicides, in vitro and in vivo, for their efficacy against the responsible pathogen Fusarium oxysporum f.sp. cubense, and to evaluate surface sterilants that could be used for sterilization purposes. Of the fung…