Hervé Alexandre

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Decanoic acid, a lipophilic agent, inhibited in vitro the plasma membrane H(+)-ATPase of Saccharomyces cerevisiae grown in YPD medium. Conversely, when decanoic acid (35 microM) was present in the growth medium, the measured H(+)-ATPase activity was four times higher than that of control cells. Km, and pH and orthovanadate sensitivity were the same for the(More)
We compared pyrosequencing technology with the PCR-ITS-RFLP analysis of yeast isolates and denaturing gradient gel electrophoresis (DGGE). These methods gave divergent findings for the yeast population. DGGE was unsuitable for the quantification of biodiversity and its use for species detection was limited by the initial abundance of each species. The(More)
Biogenic amines are molecules with allergenic properties. They are found in fermented products and are synthesized by lactic acid bacteria through the decarboxylation of amino acids present in the food matrix. The concentration of biogenic amines in fermented foodstuffs is influenced by many environmental factors, and in particular, biogenic amine(More)
  • François M Longin, Patrice Fontaine, Marc Chesney, Michel Crouhy, Nicole El Karoui, Bertrand +14 others
This article develops theoretical insight into the threshold effect in expected volatility, which means that large shocks are less persistent in volatility than small shocks. The model uses the Kyle–Admati–Pfleiderer setup with liquidity traders, informed traders, and a market maker. Information is modeled as a GARCH process. It is shown that the GARCH(More)
et Maître de Conférences à l'Université de La Rochelle. Ils sont rattachés pour le premier au Curege et au Latec (Crego) et, pour le second, au Latec (Crego). Résumé : Dans le cadre théorique du gouvernement d'entreprise, cet article étudie l'efficacité du contrôle exercé par la structure de propriété et le conseil d'administration sur les diri-geants. La(More)
Bacterial malolactic fermentation (MLF) has a considerable impact on wine quality. The yeast strain used for primary fermentation can systematically stimulate (MLF+ phenotype) or inhibit (MLF−) bacteria and the MLF process as a function of numerous winemaking practices, but the underlying molecular evidence still remains a mystery. The goal of the study was(More)
A passive erratic movement of the germinal vesicle (GV), already visible in small incompetent oocytes, is followed by an active scalloping of the nuclear membrane soon before GV breakdown (GVBD) in cultured competent oocytes. Maturation can be inhibited by activators of protein kinase A (PK-A) and protein kinase C (PK-C). Our time-lapse cinematography(More)
In this study we report for the first time a rapid, efficient and cost-effective method for the enumeration of lactic acid bacteria (LAB) in wine. Indeed, up to now, detection of LAB in wine, especially red wine, was not possible. Wines contain debris that cannot be separated from bacteria using flow cytometry (FCM). Furthermore, the dyes tested in previous(More)
Different genera and/or species of yeasts present on grape berries, in musts and wines are widely described. Nevertheless, the community of non-Saccharomyces yeasts present in the cellar is still given little attention. Thus it is not known if the cellar is a real ecological niche for these yeasts or if it is merely a transient habitat for populations(More)