Search results for "GENETICS"
showing 10 items of 12494 documents
Evolutionary Changes after Translational Challenges Imposed by Horizontal Gene Transfer
2019
International audience; Genes acquired by horizontal gene transfer (HGT) may provide the recipient organism with potentially new functions, but proper expression level and integration of the transferred genes in the novel environment are not granted. Notably, transferred genes can differ from the receiving genome in codon usage preferences, leading to impaired translation and reduced functionality. Here, we characterize the genomic and proteomic changes undergone during experimental evolution of Escherichia coli after HGT of three synonymous versions, presenting very different codon usage preference, of an antibiotic resistance gene. The experimental evolution was conducted with and without…
Negative associations between parasite avoidance, resistance and tolerance predict host health in salmonid fish populations
2020
Genetic variation in defence against parasite infections is fundamental for host–parasite evolution. The overall level of defence of a host individual or population includes mechanisms that reduce parasite exposure (avoidance), establishment (resistance) or pathogenicity (tolerance). However, how these traits operate and evolve in concert is not well understood. Here, we investigated genetic variation in and associations between avoidance, resistance and tolerance in a natural host–parasite system. Replicated populations of Atlantic salmon ( Salmo salar ) and sea trout (an anadromous form of brown trout, Salmo trutta ) were raised under common garden conditions and infected with the eye fl…
Determining stingray movement patterns in a wave-swept coastal zone using a blimp for continuous aerial video surveillance
2020
Stingrays play a key role in the regulation of nearshore ecosystems. However, their movement ecology in high-energy surf areas remains largely unknown due to the notorious difficulties in conducting research in these environments. Using a blimp as an aerial platform for video surveillance, we overcame some of the limitations of other tracking methods, such as the use of tags and drones. This novel technology offered near-continuous coverage to characterise the fine-scale movements of stingrays in a surf area in Kiama, Australia, without any invasive procedures. A total of 98 stingray tracks were recorded, providing 6 h 27 min of movement paths. The tracking data suggest that stingrays may u…
Spontaneous hybridizations between oilseed rape and wild radish
1998
The occurence of spontaneous hybridization between Brassica napus (oilseed rape) and Raphanus raphanistrum (wild radish) was investigated under different density conditions in cages and open-field experiments. Hybrids with wild radish as the seed parent were identified by screening for herbicide resistance belonging to rape. Small seed size and intermediate morphology were used to screen for hybrids with rape as the seed parent. Leaf isozyme patterns and flow cytometry provided confirmation of hybrids. Wild radish in an oilseed rape field produced as many as three interspecific hybrids per 100 plants. This is the first report of such a spontaneous event. The frequency of hybrids is expected…
Conservation status of freshwater mussels in Europe: state of the art and future challenges
2016
Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life-history traits, distribution, conservation status, habitat preferences, and main threats in order to suggest future management actions. In northern, central, and eastern Europe, a relatively homogeneous species composition is found in most basins. In southern Europe, despite the lower species richness, spatially restricted species make these basins a high conservation priority. Information on freshwater mussels in Europe is uneve…
Social phenotype extended to communities: Expanded multilevel social selection analysis reveals fitness consequences of interspecific interactions
2015
In social species, fitness consequences are associated with both individual and social phenotypes. Social selection analysis has quantified the contribution of conspecific social traits to individual fitness. There has been no attempt, however, to apply a social selection approach to quantify the fitness implications of heterospecific social phenotypes. Here, we propose a novel social selection based approach integrating the role of all social interactions at the community level. We extended multilevel selection analysis by including a term accounting for the group phenotype of heterospecifics. We analyzed nest activity as a model social trait common to two species, the lesser kestrel (Falc…
Phylogenetic placement of Cailliella praerupticola (Melastomataceae), a rare, monospecific lineage from Guinea, West Africa
2021
The genus Cailliella includes a single species, C. praerupticola, restricted to a sandstone plateau region in Coyah, Dubreka, Forecariah and Kindia Prefectures, Guinea, West Africa. Until its rediscovery in 2016, this species was known only by the type gathering made in 1937. We provide an emended description, photographs of living material, locality and habitat data, and a discussion of its conservation status. We further designate a lectotype for C. praerupticola. On the basis of morphology, Cailliella had been considered an isolated member of the tribe Melastomateae, possibly sister to Melastomastrum. We tested the classification of Cailliella by means of a phylogenetic analysis of C. pr…
Infection by Endosymbiotic “Male-Killing” Bacteria in Coleoptera
2018
Wolbachia, Rickettsia, Spiroplasma and Cardinium are endosymbiotic and intracellular bacteria known to cause numerous disorders in host reproduction, reflected in their common name “male-killers”. In this study, 297 beetle species from various taxonomic groups were screened with the use of molecular markers for the presence of infection by any of these endosymbionts. Wolbachia was found to be the most common “male-killer” among beetle hosts as it infected approx. 27% of species. Rickettsia, Spiroplasma and Cardinium were much less prevalent as they infected: 8%, 3% and 2%, respectively, of the studied beetle species. This is the first report of Cardinium presence in beetle hosts. Incidences…
There's More to the Picture Than Meets the Eye: Nitric Oxide Cross Talk with Ca2+ Signaling
2013
Abstract Calcium and nitric oxide (NO) are two important biological messengers. Increasing evidence indicates that Ca2+ and NO work together in mediating responses to pathogenic microorganisms and microbe-associated molecular patterns. Ca2+ fluxes were recognized to account for NO production, whereas evidence gathered from a number of studies highlights that NO is one of the key messengers mediating Ca2+ signaling. Here, we present a concise description of the current understanding of the molecular mechanisms underlying the cross talk between Ca2+ and NO in plant cells exposed to biotic stress. Particular attention will be given to the involvement of cyclic nucleotide-gated ion channels and…
Aspartic proteinase from barley grains is related to mammalian lysosomal cathepsin D
1991
Resting barley (Hordeum vulgare L.) grains contain acid-proteinase activity. The corresponding enzyme was purified from grain extracts by affinity chromatography on a pepstatin-Sepharose column. The pH optimum of the affinity-purified enzyme was between 3.5 and 3.9 as measured by hemoglobin hydrolysis and the enzymatic activity was completely inhibited by pepstatin a specific inhibitor of aspartic proteinases (EC 3.4.23). Further purification on a Mono S column followed by activity measurements and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the affinity-purified enzyme preparation contained two active heterodimeric aspartic proteinases: a larger 48k Da enzyme, c…