Biochemical and physiological studies of the small heat shock protein Lo18 from the lactic acid bacterium Oenococcus oeni

47 ref.; International audience

Etude biochimiques et physiologiques d'un "heat shock protein" de faible poids moléculaire d'une bactérie lactique

National audience

Influence of a reducing environment on the bioconversion of fatty acids to lactones and methyl-ketones by microorganisms : cellular and enzymatic approaches

National audience

Using specific polyclonal antibodies to study the malolactic enzyme from Leuconostoc oenos and other lactic acid bacteria.

Specific polyclonal antibodies directed against the malolactic enzyme of Leuconostoc oenos were obtained. Despite the homologies between the malolactic enzymes from Leuc. oenos and Lactococcus lactis, no immunological relationship was detected with the L. lactis malolactic enzyme, suggesting differences in their structural organization. The use of the antiserum also demonstrated that the problem of heterologous expression occurring in the recombinant Escherichia coli strain (Labarre et al. 1996a) resulted in a low synthesis of the malolactic enzyme from Leuc. oenos. Moreover, a small amount of the protein was found to be peripherally associated to the membrane of Leuc. oenos.

The diversity of the population of Botrytis cinerea collected from french vineyards

Cloning of branched chain amino acid biosynthesis genes and assays of alpha-acetolactate synthase activities in Leuconostoc mesenteroides subsp. cremoris.

A genomic library from Leuconostoc mesenteroides subsp. cremoris (Lmc) in Escherichia coli was screened for alpha-acetolactate synthase (ALS) activity using a phenotypic test detecting the production of acetolactate or related C4 derivatives (diacetyl, acetoin or 2,3-butanediol) in the culture. Four recombinant E. coli clones, with plasmids containing overlapping DNA fragments and displaying anabolic ALS activity, were selected. This activity is encoded by an ilvB gene belonging to a putative operon which contains genes highly similar to the genes of the branched chain amino acid (BCAA) operon of Lactococcus lactis subsp. lactis. This putative BCAA operon is not functional as the ilvA gene …

Ability of Wine Lactic Acid Bacteria to Metabolize Phenol Carboxylic Acids

International audience

Kinetics of lactate fermentation and citrate bioconversion by LactococcusIactisssp.Iactisin batch culture

The growth kinetics of Lactococcus lactis ssp. lactis were studied in batch culture in conditions of non-limiting lactose and the presence of citric acid. The control of pH modified growth and citrate metabolism but did not change the yield of acid formation. At controlled pH the growth rate was unaffected by citrate metabolism. Lactose was transformed to L-lactate and assay of the metabolic by-products showed some heterofermentation at the end of the growth of cultures with low growth rates. This heterofermentation was interpreted as a slowing down of glycolysis with activation of both the pyruvate formate lyase (PFL) and the pyruvate dehydrogenase complex (PDHC). Under these conditions th…