Search results for "Microbio"
showing 10 items of 8741 documents
Identification of Traits Implicated in the Rhizosphere Competence of Fluorescent Pseudomonads: Description of a Strategy Based on Population and Mode…
2009
E-book; International audience; The lack of consistency of the beneficial effects of inoculated fluorescent pseudomonads has often been related to their bad survival in the rhizosphere. In this review, we describe the strategy followed over the last decade to study traits involved in the rhizosphere competence of these bacteria. The diversity of indigenous populations associated with plant roots was first compared to that of populations associated with uncultivated soils in order to identify traits that discriminate these populations. The involvement of these bacterial traits in the rhizosphere competence was then assessed by comparing the competitiveness of a wild-type strain to that of mu…
Effect of oxidoreduction potential on aroma biosynthesis by lactic acid bacteria in nonfat yogurt
2011
; The aim of this study was to investigate the effect of oxidoreduction potential (Eh) on the biosynthesis of aroma compounds by lactic acid bacteria in non-fat yogurt. The study was done with yogurts fermented by Lactobacillus bulgaricus and Streptococcus thermophilus. The Eh was modified by the application of different gaseous conditions (air, nitrogen, and nitrogen/hydrogen). Acetaldehyde, dimethyl sulfide, diacetyl, and pentane-2,3-dione, as the major endogenous odorant compounds of yogurt, were chosen as tracers for the biosynthesis of aroma compounds by lactic acid bacteria. Oxidative conditions favored the production of acetaldehyde, dimethyl sulfide, and diketones (diacetyl and pen…
A study on texture-taste-aroma interactions: physico-chemical and cognitive mechanisms
2009
International audience; Texture–taste, texture–aroma and aroma–taste interactions were examined in custard desserts varying in viscosity (at identical composition), sucrose level and aroma nature. All reciprocal interactions were investigated, with each binary interaction addressed through an independent sensory study. Rheological, in vivo aroma release and sucrose release measurements were run in parallel to control for a possible physico-chemical origin of these interactions. Observed interactions were found to be dependent upon the nature of the sensory modalities involved; physico-chemical mechanisms could only in some instances entirely explain these interactions. Taste and aroma did n…
Inactivation of lactococcal aromatic aminotransferase prevents the formation of flora aroma compounds from aromatic amino acids in semi-hard cheese
1999
The enzymatic conversion of aromatic amino acids to aroma compounds plays a role in the formation of an undesirable floral aroma in Cheddar-like cheeses. In lactococci, the first step of aromatic amino acid degradation is a transamination, catalysed by an aromatic aminotransferase (AraT). We observed previously that in vitro, araT inactivation prevented degradation of aromatic amino acids and decreased degradation of Met and Leu. In this study we evaluated the effect of araT inactivation in Lactococcus lactis on flavour development in St. Paulin-type cheese. The degradation of amino acids was monitored by using radiolabelled amino acids and the volatile compounds formed were analysed by GC-…
Methods for studying root colonization by introduced beneficial bacteria
2003
e-Book; Some free-living rhizobacteria are considered as potential biocontrol and plant growth-promoting agents. Successful application of beneficial bacteria as microbial inoculants requires their presence and activity at the appropriate level, but even more, at the right time and place. Various markers are described in the literature to differentiate introduced bacteria from indigenous microflora and to visualize them. These markers are presented together with the methods currently applied to quantify bacterial densities and to characterize the distribution of introduced bacteria. The methods to quantify bacterial densities are either based on bacterial cultivation or not. Different types…
A mathematical method for determining genome divergence and species delineation using AFLP.
2002
The delineation of bacterial species is presently achieved using direct DNA-DNA relatedness studies of whole genomes. It would be helpful to obtain the same genomically based delineation by indirect methods, provided that descriptions of individual genome composition of bacterial genomes are obtained and included in species descriptions. The amplified fragment length polymorphism (AFLP) technique could provide the necessary data if the nucleotides involved in restriction and amplification are fundamental to the description of genomic divergences. Firstly, in order to verify that AFLP analysis permits a realistic exploration of bacterial genome composition, the strong correspondence between …
Population Structure and Comparative Genome Hybridization of European Flor Yeast Reveal a Unique Group of Saccharomyces cerevisiae Strains with Few G…
2014
Wine biological aging is a wine making process used to produce specific beverages in several countries in Europe, including Spain, Italy, France, and Hungary. This process involves the formation of a velum at the surface of the wine. Here, we present the first large scale comparison of all European flor strains involved in this process. We inferred the population structure of these European flor strains from their microsatellite genotype diversity and analyzed their ploidy. We show that almost all of these flor strains belong to the same cluster and are diploid, except for a few Spanish strains. Comparison of the array hybridization profile of six flor strains originating from these four co…
Responsable du parcours "Microbiote et Toxicologie"
2019
Organisations de colloques de portée nationale/ internationale
Construction, validation et amélioration continue de banque de spectres pour l’utilisation en routine de la spectrométrie de masse en mycologie médic…
2012
Résumé publié dans: Journal de Mycologie Médicale / Journal of Medical Mycology, sept. 2012, 55(3): 279-280. doi:10.1016/j.mycmed.2012.07.024; National audience
Diversity and interactions among strains of Fusarium oxysporum : application to biological control.
2001
International audience