Search results for "Biota"
showing 10 items of 679 documents
Détection orosensorielle des lipides alimentaires chez la souris : mécanismes impliqués et altérations au cours de l'obésité
2015
Dietary lipids are detected by the gustatory system in rodents and humans. Two candidate lipid-receptors are found in taste buds: CD36, which is involved in the fat taste as shown by studies conducted in our laboratory, and GPR120. Our results show that GPR120 is not directly involved in the gustatory detection of lipids in mice, but could rather be involved in the modulation of the sensitivity for fat. When this gustatory system works properly, food choices can meet the organism’s energy needs. Besides, the pleasure brought by the consumption of palatable foods is satisfied. However, obese people often overconsume energy-dense food. In the central nervous system, perturbations of the rewar…
Lipid and homeostatic alterations in nervous tissues associated with aging and metabolic dysregulations: implication of gut microbiota and autophagy
2020
The retina and the brain are two nervous tissues rich in lipids. Aging and metabolic syndrome (MetS) are associated with functional and physiological alterations of these tissues as well as modifications in the composition of the gut microbiota. The global objective of this thesis work is to understand the lipid and homeostatic alterations in aging and MetS contexts in the retina and the brain. In a first study, we evaluated the impact of the modifications in the composition of the gut microbiota associated with aging on the lipid/fatty acid contents of the liver and the brain (cortex). We showed that colonization of germ-free mice with the gut microbiota of old mice modulated the hepatic e…
Impact of deoxynivalenol on soil microflora and fauna
2012
F. graminearum is an important pathogen that causes head blight of cereal crops as wheat and maize. It also produces the mycotoxins (as Deoxynivalenol=DON) which are toxic to the human and animals. During the off season the pathogen survives in the soil, on weeds and in crop residues. A 24 weeks study was conducted in controlled conditions (microcosms of natural soil, 17 °C, 80% WHC) to test whether the presence of DON in the wheat crop residues gives competitive advantage to F. graminearum over the other soil microflora and fauna to survive and develop a primary inoculum during the decomposition process. This study was carried out in the presence of the whole soil biota (i.e. fungi, bacter…
Microbial ecology of the rhizosphere
2006
Part II. Selected MethodsPlant-microbe Chapitre 9 : Interactions and Soil Quality; International audience
A core microbiota of plant and earthworm interaction? Phylogenetic and functional aspects
2017
International audience; The core microbiota concept has been proposed to describe the subset of a microbiota (e.g. the rhizosphere microbial community) associated with a given host (e.g. a plant) going beyond macroenvironment differences (e.g. soil type), and characterized by taxonomic markers (e.g. 16S rRNA gene sequences). Its existence has been questioned by geographical studies, showing the overruling soil type effect in shaping microbial communities. As far as biotic determinants are concerned, several “hosts” or macroorganisms are impacting a given habitat and its specific microbial community. In soils, there is an overlap between the so-called rhizosphere and the drilosphere, defined…
Drought stress impacts the microbiota mediating iron dynamic in the pea rhizosphere
2022
Agroécologie, INRAE, Institut Agro, Université de Bourgogne - Université de Bourgogne Franche-Comté, Dijon, FranceMicrobiota, with their consortia of genomes, extend the genetic repertoires of host plants to form ‘extended genotypes’, resulting in extended host phenotypes. Trecently, the term ‘holobiont’, which encompasses the host plant plus its associated microbiota, has been proposedHow environmental properties impact both the plant and microbial components of the holobiont, and its phenotype, still remain to be explored.We addressed this question by testing the impact of different abiotic conditions (drought stress and soil pH) on plant and microbial phenotypes in relation to iron. Iron…
All-day activity of Dolichovespula saxonica (Hymenoptera, Vespidae) colonies in Central Finland
2022
In social vespid wasps, colony activity varies at many temporal scales. We studied the peak season activity (number of individuals entering the nest per min) of colonies of the social vespine wasp Dolichovespula saxonica in its native range in boreal Finland. Six colonies were monitored non-stop for a full day, starting before sunrise and ending after sunset. Shorter monitoring was carried out before and/or after the full-day monitoring. All colonies were active before sunrise and after sunset, and the overall activity was positively linked with colony size. Activity showed irregular minute-to-minute cycles in all colonies. The broader within-day dynamics were idiosyncratic among the coloni…
Defining gut mycobiota for wild animals: a need for caution in assigning authentic resident fungal taxa
2021
Animal gut mycobiota, the community of fungi that reside within the gastrointestinal tract, make an important contribution to host health. Accordingly, there is an emerging interest to quantify the gut mycobiota of wild animals. However, many studies of wild animal gut mycobiota do not distinguish between the fungi that likely can reside within animal gastrointestinal tracts from the fungal taxa that are non-residents, such as macrofungi, lichens or plant symbionts/pathogens that can be ingested as part of the host’s diet. Confounding the non-resident and resident gut fungi may obscure attempts to identify processes associated with the authentic, resident gut mycobiota per se. To redress th…
Role of the microbiota in the defense against infections by Enterococci
2017
Resumen de la Tesis : “Role of the microbiota in the defense against infections by Enterococci” Introducción El tracto gastrointestinal está colonizado por centenares de especies de bacterias comensales. Se ha visto en los últimos años que dichas bacterias presentan un papel crucial en la prevención y resolución de enfermedades infecciosas. La microbiota comensal inhibe a patógenos oportunistas mediante mecanismos (i) de interacción directa, por producción de sustancias inhibitorias o competición por nutrientes (ii) indirectos, por la inducción del sistema inmune. El tratamiento con antibióticos altera la composición de la microbiota intestinal promoviendo la colonización intestinal por pat…
No sejas ādas mikrobiotas izdalīto Staphylococcus aureus jutība pret antibakteriālajiem līdzekļiem
2021
Darba aktualitāte: Pēdēja laikā Staphylococcus aureus rezistence pret zālēm nemitīgi palielinājās. Pret antibiotikām rezistentas baktērijas tiek uzskatītas par vienu no mūsdienu nopietnākajiem draudiem cilvēku veselībai. Darba mērķis: Noteikt baktēriju sejas ādas kolonizāciju veseliem cilvēkiem un noskaidrot izolēto S.aureus celmu jutību pret antibakteriāliem līdzekļiem. Pielietotas metodes: Tika pielietoti BBL™ disku difūzijas testi un Crystal™ ID metode, E-testi. Datu analīzei tika izmantota Microsoft Excel 2019 datorprogramma. Rezultāti: S.aureus izolātiem tika noteikta 100% jutība pret cefoksitīnu (MSSA), vankomicīnu un rezistence pret klindamicīnu – 6,7%, eritromicīnu – 6,7%, ciproflok…