Search results for "Invasion"
showing 10 items of 214 documents
Antibiotrophie : une fonction émergente favorisant l’implantation des bactéries antibiorésistantes dans les sols
2021
National audience; La fonction antibiotrophique, permettant l’utilisation d’antibiotiques comme source nutritive, arécemment été découverte chez des bactéries antibiorésistantes environnementales. Pourvérifier si leur avantage sélectif en environnements pollués s’en trouvait augmenté, nous avonsconduit une expérience en microcosmes dans laquelle Microbacterium sp. C448 (C448),présentant des capacités de résistance et de dégradation vis-à-vis des sulfamides, a été inoculéedans quatre sols supplémentés ou non par l’antibiotique sulfaméthazine (SMZ) et/ou du lisier.Après un mois d’incubation, C448 n’a été détectée que dans les sols traités avec la SMZ,indiquant une faible compétitivité de la s…
Microbial diversity and structure are drivers of the biological barrier effect against Listeria monocytogenes in soil
2013
International audience; Understanding the ecology of pathogenic organisms is important in order to monitor their transmission in the environment and the related health hazards. We investigated the relationship between soil microbial diversity and the barrier effect against Listeria monocytogenes invasion. By using a dilution-to-extinction approach, we analysed the consequence of eroding microbial diversity on L. monocytogenes population dynamics under standardised conditions of abiotic parameters and microbial abundance in soil microcosms. We demonstrated that highly diverse soil microbial communities act as a biological barrier against L. monocytogenes invasion and that phylogenetic compos…
How to explain the introduction of common ragweed into Europe during the XIXth century?
2012
EA EcolDur (équipe CAPA) CT3; Various reasons can explain the success of A. artemisiifolia in France and in Europe :* introduction of plants from various sources (in space and time)* strong variability (morphology, size, etc.) * ecological plasticityDifferent situations across areas and countriesThe dominant habitats and the spread vector can differPotentially strong effects of the landscape (soil use)
Human-induced hybridization and population bottleneck : population genetics, morphometrics and parasitology applied to the invaded and invasive tilap…
2011
Biological invasions are recognized as a significant evolutionary factor over short time scales. In particular, their effect is well recorded on the genetic structure of populations, the patterns of phenotypic evolution and the richness of parasite fauna associated to invasive populations. This study aims at quantifying the consequences of a biological invasion according to these three levels (genetical, phenotypical and parasitological) taking as example the Mozambique tilapia Oreochromis mossambicus. This African cichlid is characterized by an unusual conservation status since it is both (i) ranked among the world’s worst invasive species due to its global dispersion during the 20th centu…
Mise en place d'un modèle in vivo de colonisation digestive stable à C. Abicans chez la souris immunocompétente
2012
Les levures du genre Candida sont des agents pathogènes opportunistes responsables de candidoses invasives chez les sujets immunodéprimés, et sont associées à un taux de mortalité élevé. Elles représentent 8 à 15% des infections nosocomiales hématogènes et Candida albicans est l’espèce la plus fréquemment isolée en pathologie humaine. Initialement C. albicans appartient à la flore commensale intestinale, buccale et vaginale de l’homme. Ce commensalisme résulte d’un équilibre entre les propriétés biologiques de la levure et les systèmes de défense de l’hôte. La rupture de cet équilibre chez un patient fragilisé aura pour conséquence une colonisation intense des muqueuses favorisant un envahi…
Species Accounts of 100 of the Most Invasive Alien Species in Europe: Ambrosia artemisiifolia Linnaeus, common ragweed (Asteraceae, Magnoliophyta)
2009
International audience
L'ambroisie se développerait au nord de l'Europe
2014
EA EcolDur
No performance reduction at the present northern edge of Ambrosia artemisiifolia L. invasion range
2014
Plant populations at range edges may exhibit reduction of performances and fitness. In the case of biological invasions, such a reduction could be associated with a slowing down of the spread and explain the non-naturalization of a species outside its present invasion range. Common ragweed (Ambrosia artemisiifolia L.) is an ideal model to investigate such processes, since it is invasive in France but not naturalized in northern countries, such as Belgium and the Netherlands. In this study, we test if the performances of ragweed populations vary among different invasion zones. Three populations were selected in each of four invasion zones in Western Europe: 1) French invasion area; 2) northe…
Enterocytes'tight junctions play a protective role in limiting invasion of Candida albicans into intestinal cells
2013
National audience; C. albicans is a commensal yeast of the mucous membranes in healthy humans that can also be responsible for disseminated candidiasis, mainly originating from the digestive tract in vulnerable patients. Deciphering the cellular and molecular mechanisms of the interaction of C. albicans with enterocytes is necessary to better understand the basis of commensalism and pathogenicity of the yeast and to improve the management of disseminated candidiasis. In intestinal epithelia, E-cadherin is constitutive of the Adherens Junctions localized just below the Tight Junctions (TJs) which ensure impermeability of the intestinal barrier. We hypothesized the absence of endocytosis of C…
Importance of seeds in the process of common ragweed invasion
2012
International audience; Ambrosia artemisiifolia L. (common ragweed) was introduced into Europe at the end of the 1900s and is now present in several European countries. This annual invasive plant produces seeds that are highly polymorphic. Common ragweed can produce only a few thousand highly viable seeds. Many studies have focused on the seed stage. Greater seedling emergence for the seeds placed near the soil surface could explain the success of this species in open habitats, where the probability of deeper burial is low. Emergence percentage was found to decrease as burial depth increased from 2 to 8 cm, and no germination nor seedling emergence was observed for the seeds buried from 10-…