Search results for "bacteria."

Single cell analysis evidence Heterogeneous expression of the Agr communication system of Listeria monocytogenes

2012

http://prodinra.inra.fr/record/271694EAMERSCT3 EJ3; Communication, often referred as Quorum Sensing, is involved in the adaptation of most bacteria to their environment. In the genus Listeria, the agr communication system affects the biology of Listeria monocytogenes during saprophytic life (biofilm formation) and during infection. In the present study, we investigated in situ agr expression of six isolates of L. monocytogenes by combining gfp reporters, flow cytometry and fluorescent microscopy during plantonic growth and dynamic flow cell biofilm set ups. Unexpectedly, during growth in TSB homogenised liquid cultures incubated at 25°C, while auto-inducer concentration was uniform, statist…

Interactions between a mycorrhiza helper bacterium and arbuscular mycorrhizas

2009

Pseudomonas fluorescens C7R12 was shown to promote arbuscular mycorrhization and to act as a ‘Mycorrhiza Helper Bacteria’ (MHB). The complex interactions between this model strain, Arbuscular Mycorrhizal (AM) fungi and host-plants were analysed by assessing the specificity of these interactions and by characterizing bacterial cell organization on mycorrhizal roots. Evaluation of the interaction specificity relied on the comparison of the bacterial effect on (i) the in vitro saprophytic growth of Glomus mosseae and Gigasopora rosea and (ii) the root colonization of two different plant species (Medicago truncatula and Lycopersicon esculentum) by the two AM fungal species. Characterization of …

Evolution of genetic degradation potential of pesticide-degrading bacterial communities

2009

International audience

Use of PCAH as a molecular marker for estimating the diversity of the protocatechuate-degrading bacterial community in soil environment

2007

Microorganisms degrading phenolic compounds play an important role in soil carbon cycling. The pcaH gene encoding a key ring-cleaving enzyme of the β -ketoadipate pathway was selected as a functional marker. Using a degenerate primer pair, pcaH fragments were cloned from two soils. The RFLP screening of 150 pcaH clones yielded 68 RFLP families. Comparison of 86 deduced amino acid sequences displayed 70 % identity to known PcaH sequences. Phylogenetic analysis results in two major groups mainly related to PcaH sequences from Actinobacteria and Proteobacteria phyla. This gene constitutes a suitable molecular marker to study the diversity of this functional group.

Translation of metagenomics agroecosystems in ecological services

2011

National audience

Spatial distribution of ammonia oxidizing bacteria and archaea across a 44-hectare farm related to ecosystem functioning

2011

Spatial processes driving soil microbial community assembly on a wide scale

2012

International audience; Soil houses a huge biodiversity involved in ecological services through microbial community assembly. However, processes driving soil microbial community assembly are still scarcely understood, particularly the relative importance of environmental heterogeneity regarding to dispersal limitations. This can be achieved through studying the determinism of taxa-area relationship (TAR, how community composition change with geographic distance), a fundamental relationship in ecology. Here, a biogeographical approach was applied on a wide scale to evaluate TAR for soil bacterial and fungal communities and to partition their spatial variations into environmental heterogeneit…

Factors influencing spatial patterns of activity of denitrifying bacteria in a grassland soil

2008

International audience

Les sols et la résistance aux antibiotiques

2018

National audience; Les sols renferment des communautés de microorganismes très diversifiées et très abondantes (jusqu’à 1010 bactéries par gramme de sol). La production d’antibiotiques et la résistance aux antibiotiques est un des mécanismes d’interaction entre microorganismes des sols. L’antibiose par production d’antibiotique est un mécanisme très ancien utilisé par les bactéries et les champignons pour limiter le développement de bactéries compétitrices. Les sols sont donc un réservoir potentiel de bactéries résistantes aux antibiotiques (BRA) et de gènes de résistance aux antibiotiques (GRA). Ce pool de gènes de résistance des sols est appelé le résistome des sols, il constitue un réser…

Survie et devenir des bactéries résistantes aux antibiotiques dans le sol et les systèmes de culture

2018

National audience; Les sols abritent des communautés de microorganismes extrêmement diversifiées et très abondantes (jusqu’à 1010 bactéries par gramme de sol). La production d’antibiotiques et la résistance aux antibiotiques est un des mécanismes d’interaction entre microorganismes de l’environnement et des sols en particulier. L’antibiose par production d’antibiotique est un mécanisme très ancien utilisé par les bactéries et les champignons pour limiter le développement de bactéries compétitrices. Les sols sont donc un réservoir potentiel de bactéries résistantes aux antibiotiques (BRA) et de gènes de résistance aux antibiotiques (GRA). Ce pool de gènes de résistance des sols est appelé le…