Search results for "Bacteria"
showing 10 items of 4919 documents
Influence of type III bacterial secretion system on the interactions between plant and non pathogenic fluorescent Pseudomonads spp.
2010
No abstract
Microbial Community Structure and Density Under Different Tree Species in an Acid Forest Soil (Morvan, France)
2005
Overexploitation of forests to increase wood production has led to the replacement of native forest by large areas of monospecific tree plantations. In the present study, the effects of different monospecific tree cover plantations on density and composition of the indigenous soil microbial community are described. The experimental site of "Breuil-Chenue" in the Morvan (France) was the site of a comparison of a similar mineral soil under Norway spruce (Picea abies), Douglas fir (Pseudotuga menziesii), oak (Quercus sessiflora), and native forest [mixed stand dominated by oak and beech (Fagus sylvatica)]. Sampling was performed during winter (February) at three depths (0-5, 5-10, and 10-15 cm…
Mapping field-scale spatial distribution patterns of size and activity of the denitrifier community
2008
International audience
Phylogenetic comparison of symbiotic (nodC and nifH) and 16S rRNA genes in strains of Rhizobium, Mesorhizobium and Bradyrhizobium isolated from Astra…
2000
Various studies reported different conclusions on the phylogenetic relationship between symbiotic (nod and nif) and chromosomal (16S rRNA) genes in rhizobia (Haukka et al, 1998). Some studies suggested that the phylogeny of nod genes could be related with the host plant (Ueda et al., 1995). In a previous study, rhizobia (44 isolates) from Astragalus, Oxytropis and Onobrychis pp have been classified into 14 distinct 16S rRNA gene types independently of their host plant and geographic origin. The majority of isolates were classified within the genus Mesorhizobium, and few within Rhizobium and Bradyrhizobium genera (Laguerre et al., 1997). The aim of the present study was to determine the dive…
Loss in microbial diversity affects nitrogen cycling in soil
2013
International audience; Microbial communities have a central role in ecosystem processes by driving the Earth's biogeochemical cycles. However, the importance of microbial diversity for ecosystem functioning is still debated. Here, we experimentally manipulated the soil microbial community using a dilution approach to analyze the functional consequences of diversity loss. A trait-centered approach was embraced using the denitrifiers as model guild due to their role in nitrogen cycling, a major ecosystem service. How various diversity metrics related to richness, eveness and phylogenetic diversity of the soil denitrifier community were affected by the removal experiment was assessed by 454 s…
Strategies for analyzing interactions between arbuscular mycorrhiza and bacteria
2013
National audience
New perspectives and approaches in plant growth-promoting rhizobacteria research
2007
International audience; In the context of increasing international concern for food and environmental quality, use of Plant Growth-Promoting Rhizobacteria (PGPR) for reducing chemical inputs in agriculture is a potentially important issue. PGPR are root-colonizing bacteria that exert beneficial effects on plant growth and development, but they can be also employed in the control of plant pathogens, for enhancing the efficiency of fertilizers, and for degrading xenobiotic compounds. This book provides an update by renowned international experts on the most recent advances in the ecology of these important bacteria, the application of innovative methodologies for their study, their interactio…
Inactivation of PadR, the repressor of the phenolic acid stress response, by molecular interaction with Usp1, a universal stress protein from Lactoba…
2009
ABSTRACT The phenolic acid decarboxylase gene padA is involved in the phenolic acid stress response (PASR) in gram-positive bacteria. In Lactobacillus plantarum , the padR gene encodes the negative transcriptional regulator of padA and is cotranscribed with a downstream gene, usp1 , which encodes a putative universal stress protein (USP), Usp1, of unknown function. The usp1 gene is overexpressed during the PASR. However, the role and the mechanism of action of the USPs are unknown in gram-positive bacteria. Therefore, to gain insights into the role of USPs in the PASR; (i) a usp1 deletion mutant was constructed; (ii) the two genes padR and usp1 were coexpressed with padA under its own promo…
Biotechnological applications of the sepiolite interactions with bacteria: Bacterial transformation and DNA extraction
2020
International audience; Among the various clay minerals, sepiolite, which is a natural nanofibrous silicate that exhibit a poor cell toxicity, is a potential promising nanocarrier for the non-viral and stable transfer of plasmid DNA into bacteria, mammalian and human cells. We first show here that sepiolite binds to bacteria, which can be useful in decontamination protocols. In a previous research we have shown that is possible to modulate the efficiency of the absorption of different types of DNA molecules onto sepiolite, and that the DNA previously adsorbed could be recovered preserving the DNA structure and biological activity. Taking advantage of both, the sepiolite/bacteria and sepioli…
Current and New Insights on Molecular Methods to Identify Microbial Growth in Fruit Juices
2018
International audience; Identification of microorganisms in fruit juices plays an important role as it determines the viability of this food product from a commercial point of view. Several microorganisms use fruit as a substrate, thus causing spoilage and generating off‐flavors and odors. In addition, under favorable conditions, toxigenic fungi can produce mycotoxins in fruit juices. Conventional detection and enumeration of microorganisms using traditional plating assays are accurate and can detect low microbial contamination levels. However, in most cases they require long detection times. In recent years, the food industry has shown increased interest in developing new methods with incr…