Action de la 8-azaguanine sur la synthèse de pénicillinase chez Bacillus cereus

Action of 8-azaguanine on the synthesis of penicillinase in Bacillus cereus. Previous work on Bacillus cereus has indicated that protein synthesis is partially inhibited in the presence of azaguanine and that the synthesis of penicillinase (penicillin amido-β-lactamhydrolase, EC 3.5.2.6) is apparently more affected by the analog than the synthesis of other proteins. A search for the presence of an "abnormal" penicillinase under these conditions was made in the present work by immunological reactions and by column chromatography. Among the proteins secreted by the bacteria in presence of azaguanine, there is no other protein similar enough to penicillinase to be detected by immunological reactions. Similarly, the column chromatography experiments do not favour the hypothesis that other, different proteins might be synthesized under these conditions. © 1966.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Possible production of several exopenicillinases by Bacillus cereus

DURING the course of an investigation of the specificity of protein synthesis in Bacillus cereus, the proteins excreted by this micro-organism in exponential growth have been isolated and examined with the help of a variety of techniques. Among these proteins, the enzyme penicillinase is found. © 1962 Nature Publishing Group.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Long-term administration of resveratrol at low doses improves neurocognitive performance as well as cerebral blood flow and modulates the inflammatory pathways in the brain

International audienc

Lycopene modulates THP1 and Caco2 cells inflammatory state through transcriptional and nontranscriptional processes.

We revisited the action of a carotenoid, the lycopene, on the expression of proinflammatory genes, reactive oxygen species (ROS) production, and metalloprotease (MMP9) activity. THP1 and Caco2 cell lines were used as in vitro models for the two main cell types found in intestine tissue, that is, monocytes and epithelial cells. Proinflammatory condition was induced using either phorbol ester acetate (PMA), lipopolysaccharide (LPS) or tumor necrosis factor (TNF). In THP1 cells, short term pretreatment (2 h) with a low concentration (2 muM) of lycopene reinforce proinflammatory gene expression. The extent of the effect of lycopene is dependent on the proinflammtory stimulus (PMA, LPS or TNF) used. Lycopene enhanced MMP9 secretion via a c-AMP-dependent process, and reduced ROS production at higher concentrations than 2 muM. Cell culture media, conditioned by PMA-treated monocytes and then transferred on CaCo-2 epithelial cells, induced a proinflammatory state in these cells. The extent of this inflammatory effect was reduced when cells has been pretreated (12 h) with lycopene. At low concentration (2 muM or less), lycopene appeared to promote an inflammatory state not correlated with ROS modulation. At higher concentration (5 muM-20 muM), an anti-inflammatory effect takes place as a decrease of ROS production was detected. So, both concentration and time have to be considered in order to define the exact issue of the effect of carotenoids present in meals

La mort subite médico-légale

info:eu-repo/semantics/publishe

Resveratrol-mediated glycemic regulation is blunted by curcumin and is associated to modulation of gut microbiota

International audienceThe polyphenols resveratrol (RSV) and curcumin (Cur) are phytoalexines and natural antibiotics with numerous pharmacological functions and metabolic impacts. Recent evidences show a broad control of gut microbiota by polyphenols which could influence glycemic regulation. The aim of this work is to estimate the respective effect of RSV and Cur alone or in association on the control of glycemia and on gut microbiota. A 5-week chronic treatment of hyperglycemic mice with RSV and/or Cur resulted in a differential effect on glucose tolerance test and modified gut microbiome. We precisely identified groups of bacteria representing a specific signature of the glycemic effect of RSV. Inferred metagenomic analysis and metabolic pathway prediction showed that the sulfur and branched-chain amino-acid (BCAA) metabolic activities are tightly correlated with the efficacy of RSV for the control of glycaemia. The impact on BCAA metabolism was further validated by serum metabolomics analysis. Altogether, we show that polyphenols specifically impact gut microbiota and corresponding metabolic functions which could be responsible for their therapeutic role