Inhibition of Shiga toxin-converting bacteriophage development by novel antioxidant compounds

Oxidative stress may be the major cause of induction of Shiga toxin-converting (Stx) prophages from chromosomes of Shiga toxin-producing Escherichia coli (STEC) in human intestine. Thus, we aimed to test a series of novel antioxidant compounds for their activities against prophage induction, thus, preventing pathogenicity of STEC. Forty-six compounds (derivatives of carbazole, indazole, triazole, quinolone, ninhydrine, and indenoindole) were tested. Fifteen of them gave promising results and were further characterized. Eleven compounds had acceptable profiles in cytotoxicity tests with human HEK-293 and HDFa cell lines. Three of them (selected for molecular studies) prevent the prophage induction at the level of expression of specific phage genes. In bacterial cells treated with hydrogen peroxide, expression of genes involved in the oxidative stress response was significantly less efficient in the presence of the tested compounds. Therefore, they apparently reduce the oxidative stress, which prevents induction of Stx prophage in E. coli

Pseudonocardians A–C, New Diazaanthraquinone Derivatives from a Deap-Sea Actinomycete Pseudonocardia sp. SCSIO 01299

Pseudonocardians A–C (2–4), three new diazaanthraquinone derivatives, along with a previously synthesized compound deoxynyboquinone (1), were produced by the strain SCSIO 01299, a marine actinomycete member of the genus Pseudonocardia, isolated from deep-sea sediment of the South China Sea. The structures of compounds 1–4 were determined by mass spectrometry and NMR experiments (1H, 13C, HSQC, and HMBC). The structure of compound 1, which was obtained for the first time from a natural source, was confirmed by X-ray analysis. Compounds 1–3 exhibited potent cytotoxic activities against three tumor cell lines of SF-268, MCF-7 and NCI-H460 with IC50 values between 0.01 and 0.21 μm, and also showed antibacterial activities on Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 and Bacillus thuringensis SCSIO BT01, with MIC values of 1–4 μg mL−1

Aides avancées à la conduite automobile

Introduction au numéro spécial de la revue "travail humain" consacré à l'aide à la conduit

Architectural theory from the renaissance to the present

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