Search results for "Oenococcus"
showing 5 items of 85 documents
Application of MALDI-TOF-MS and nested SAPD-PCR for discrimination ofOenococcus oeniisolates at the strain level
2015
Oenococcus oeni is the most important lactic acid bacterium during vinification and is frequently used as a commercial starter culture for malolactic fermentation. Since different strains exhibit a high heterogeneity concerning wine-related physiological characteristics, reliable methods for their differentiation at the strain level are needed, especially for the development of starter cultures. Microbial identification by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has increased over the last few years. In the present study, we used MALDI-TOF-MS for the differentiation of 11 O. oeni isolates originating from 5 different wine-growing reg…
Estudio de la diversidad y evaluación de las relaciones fenotipo-genotipo para la búsqueda de cepas malolácticas de Oenococcus oeni
2015
El vino es una bebida obtenida por fermentación del mosto de uva. Durante la fermentación participan las levaduras y las bacterias lácticas que son responsables de la fermentación alcohólica y maloláctica, respectivamente. La fermentación alcohólica consiste fundamentalmente en la transformación de los azúcares del mosto en etanol y CO2, mientras que la fermentación maloláctica consiste en la conversión de ácido málico, propio del mosto, en ácido láctico y CO2. De todas las especies de bacterias lácticas relacionadas con la vinificación, Oenococcus oeni es la responsable generalmente de la FML, ello se debe a que es la que mejor tolera las condiciones estresantes del vino. Por esta razón, e…
Distinct amino acids of the Oenococcus oeni small heat shock protein Lo18 are essential for damaged protein protection and membrane stabilization
2010
The small heat shock protein (smHsp) Lo18 from lactic acid bacteria Oenococcus oeni reduces in vitro thermal aggregation of proteins and modulates the membrane fluidity of native liposomes. An absence of information relating to the way in which the smHsp demonstrates a stabilizing effect for both proteins and membranes prompted this study. We expressed three Lo18 proteins with amino acid substitutions in Escherichia coli to investigate their ability to prevent E. coli protein aggregation and their capacity to stabilize E. coli whole-cell membranes. Our results showed that the alanine 123 to serine substitution induces a decrease in chaperone activity in denaturated proteins, and that the ty…
Influence of fatty acids on the growth of wine microorganisms Saccharomyces cerevisiae and Oenococcus oeni
1998
The effects of fatty acids, extracted during prefermentation grape skin-contact on Saccharomyces cerevisiae and Oenococcus oeni, were studied. The influence of skin-contact on total fatty acid content was evaluated both in Chardonnay must and in synthetic medium. Prior to alcoholic fermentation, the skin-contact contributes to a large enrichment of long-chain fatty acids (C 16 to C 18:3 ). These results induced a positive effect on yeast growth and particularly on cell viability. In the skin-contact fermented media, levels of C 12 and especially C 10 are lower and macromolecules content higher than in controls. This production of extracellular mannoproteins and the reduction of medium-chain…
Regulation of hdc expression and HDC activity by enological factors in lactic acid bacteria.
2008
Aims: The aim of this work was to study the influence of enological factors on the histidine decarboxylase gene (hdc) expression and on histidine decarboxylase enzyme (HDC) activity in Lactobacillus hilgardii, Pediococcus parvulus and Oenococcus oeni. Methods and Results: Cell extracts and whole cells were used. Glucose, fructose, malic acid and citric acid diminished the hdc expression. Ethanol did not increase hdc expression or activity in cells, but increased HDC activity. Temperature and pH had effect on the activity of HDC but not on hdc expression. Tartaric acid and l-lactic acid, and sulphur dioxide (SO2) had no effect on enzyme synthesis and activity. Bacterial species differ in t…