Interactions between Kluyveromyces marxianus from cheese origin and the intestinal symbiont Bacteroides thetaiotaomicron: Impressive antioxidative effects

The effects of yeast Kluyveromyces marxianus S-2-05, of cheese origin, were assessed on the intestine anaerobe symbiont Bacteroides thetaiotaomicron ATCC 29741 to unveil any changes in its antioxidant properties. To this end, these microorganisms were grown and incubated either separately, or co-incubated, under anaerobic atmosphere. Afterwards, the microbial cells were recovered and washed, and extracts were prepared using a sterile detergent solution to mimic the intestine detergent content. The extracts prepared from K. marxianus S-2-05 and reference strain K. marxianus MUCL 29917, grown under different conditions, were assessed for their antioxidant properties against superoxide anion and hydrogen peroxide. Extracts from both yeasts showed antioxidative effects, which were particularly important for K. marxianus S-02-5 after anaerobic incubation. Moreover, K. marxianus S-02-5 displayed a high level of activity against the aforementioned reactive oxygen species, enhancing that of B. thetaiotaomicron ATCC 29741, after the co-incubation process. Two-dimensional polyacrylamide gel electrophoresis was used to separate the proteins extracted. Superoxide dismutase, thiol peroxidase, rubrerythrin -intensively produced by B. thetaiotaomicron induced by the yeast-were identified by mass spectrometry. The antioxidative potential evidenced for K. marxianus S-02-5 is another advantage which could justify the utilization of this strain as a probiotic for countering intestinal inflammatory processes. © 2017 Elsevier Lt

Learning in games with continuous action spaces and unknown payoff functions

International audienc

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

47 ref.International audienc

Fungal diversity of “Tomme d'Orchies” cheese during the ripening process as revealed by a metagenomic study

Tomme d'Orchies is an artisanal pressed and uncooked cheese produced and marketed in the north of France. This study aimed at showing the fungal microbiota evolution of this cheese using a metagenetic based Illumina technology targeting the ITS2 domain of 5.8S fungal rDNAs. To this end, samples were taken from the rind and the core of different cheeses, after 0, 1, 3, 7, 14 and 21 days of ripening. The data underpinned the prevalence of Yarrowia lipolytica and Galactomyces geotrichum for both microbiotas. Unusual species including Clavispora lusitaniae, Kazachstania unispora and Cladosporium cladosporioides were also detected, but their origins remain to be ascertained. The metagenomic revealed also the presence of Kluyveromyces and Debaryomyces species. © 2017 Elsevier B.V

Engineering of Bacillus subtilis physiological functionalities towards the production of mycosubtilin anteiso-C17

International audienc

Environmental factors and pleiotropic regulators influence homologous compound pattern of mycosubtilin produced by Bacillus subtilis ATCC 6633

International audienc

Production of a novel mixture of mycosubtilin by mutants of Bacillus subtilis

Using promoter exchange and gene knock-out strategies, two mutant strains, the so-called BBG116 and BBG125, were constructed from Bacillus subtilis wild-type strain ATCC 6633, a surfactin and mycosubtilin producer. Compared to the parental strain, both mutants overproduced constitutively mycosubtilin, while BBG125 had lost the ability to synthesize surfactin. Surprisingly, BBG125 was found to produce about 2-fold less mycosubtilin than BBG116 despite an expected higher availability of the cytoplasmic precursors and cofactors pool for biosynthesis. Further physiological characterization of BBG125 also highlighted: (i) a strong influence of temperature on mycosubtilin biosynthesis in BBG125 with a maximal productivity observed at 22. °C, compared to 15 and 30. °C; (ii) substantial changes in fatty acid profiles and thereby in mycosubtilin isoforms, compared to the wild-type strain; and (iii) the presence of five novel mycosubtilin isoforms. The antifungal activities of the new mix were higher than or equal to those of purified isoforms. © 2013 Elsevier Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/inPres