Affichage des résultats 1061 à 1080 sur 1600 au total
Le LBBE impliqué dans un projet national sur la phagothérapie
Recent global changes in climate impose new energetical constraints. As evidence for widespread biological impacts of recent climate change accumulates, there is an increasing interest in understanding how organisms adapt to changing environments. Direct abiotic and indirect biotic factors are impacting on individuals' energy balance. Long-lived vertebrates seem to largely compensate these energetic bottlenecks by phenotypic plasticity. We present a summary of current works on the flexible control of energy expenditure conferred by phenological shifts and heterothermy that provide the ability to respond to environmental variations. Although some species may adapt to climate change through phenotypic plasticity, there are significant limits and costs to this strategy. A detailed understanding of physiological and behavioural mechanisms involved would provide a powerful tool for predicting future ecological patterns and managing their consequences.
A central question in molecular evolution concerns the nature of phenotypic transitions, in particular if neutral mutations hamper or somehow facilitate adaptability of proteins or RNAs to new requirements.Proteins and RNA have been found to accomplish different task by fluctuate between different phenotypes (structures), with frequencies and thus intensity of the associated trait being proportional to their stability. Therefore, functional promiscuity may correspond to different structures with energies close to the ground state which then represent multiple selectable traits. We here postulate that these near-ground state structures facilitate smooth transitions between phenotypes. Using biophysical model systems with exhaustive mappings of genotypes (sequences) onto phenotypes (structures), we demonstrate that this is indeed possible because of a smooth gradient of stability along which any phenotype can be optimised and also because of mutational proximity of similar phenotypes in genotype space.Our model provides a rationalisation of the intriguing, and otherwise puzzling experimental observation that adaptation to new requirements, e.g. latent function of a promiscuous enzyme, can proceed while the "old", phenotypically dominant function is maintained along a series of seemingly neutral mutations.Thus pleiotropy may facilitate adaptation of latent traits BEFORE gene duplications and increase the effective adaptability of proteins
We are exploring techniques using single cell genomic sequencing in human beings for the purpose of defining phylogenetic trees to explain the relationship of cells within defined human tissues. I will discuss how we used single cell exome and whole genome sequencing to identify patient and donor adipocytes in human white adipose tissue biopsies taken from bone marrow recipients and discuss future projects using similar methods to explore cellular identities in human tissue samples.
Thèse de Wandrille DUCHEMIN le lundi 4 décembre 2017 à 14 h, amphithéâtre BU (La Doua)
Habilitation à diriger des Recherches de Vincent Daubin - Jeudi 6 décembre 2012 - 14h00 - Amphi Ampère Bâtiment Lippmann
HDR de Bastien BOUSSAU le jeudi 21 mars 2019 à 14 h, salle des conférences BU (la Doua)
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"Démystifier la recherche scientifique et la faire découvrir au grand public dans un cadre détendu. Parce que non, dans un labo, ça ne se passe pas toujours comme dans les experts."
It has long been argued that single species laboratory tests do not necessary predict the ecological effects of chemicals in the field. By ecological effects is used to mean effects on populations, communities and ecosystems. However ecotoxicologists have continued to use single species laboratory tests. My short research career has involved a number of change in direction - or backflips - in my attitude to these tests and I will illustrate this with examples of the effect of increased salinity on stream invertebrates, insecticides and fungicides on stream invertebrates and herbicides on benthic diatoms. I will discuss how such simple test systems combined with more complicated test systems can potential serve as models to test hypothesises as to how chemical stressors effect ecological systems.
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