RESUMO
There are now abundant data indicating that Mycobacterium tuberculosis uses fatty acids as a carbon source in vivo. A key enzyme in gluconeogenesis, missing in the original annotation of the M. tuberculosis genome, is fructose 1,6-bisphosphatase (FBPase; EC 3.1.3.11). The authors have shown that M. tuberculosis Rv1099c, a glpX homologue, can complement Escherichia coli mutants lacking FBPase. The protein encoded by Rv1099c was shown to have FBPase activity. Rv1099c was expressed at significant levels in M. tuberculosis, and may encode the major FBPase of this pathogen.
Assuntos
Frutose-Bifosfatase/genética , Gluconeogênese/genética , Mycobacterium tuberculosis/enzimologia , Escherichia coli/genética , Frutose-Bifosfatase/metabolismo , Teste de Complementação Genética , Genoma Bacteriano , Dados de Sequência Molecular , Mycobacterium tuberculosis/genética , Homologia de Sequência de AminoácidosRESUMO
Induction of the Mycobacterium tuberculosis dosR gene, which is known to respond to hypoxia, was measured using RTq-PCR following exposure to different stresses. Increased expression was seen after exposure to S-nitrosoglutathione (GSNO), ethanol and (to a lesser extent) H2O2, but not heat- or cold-shock. We also demonstrated that hspX, which is dependent on dosR for expression, is induced when cultures are left standing for 30 min, while significant but minor induction was seen following a 10 min centrifugation. Microarray analysis was used to compare gene expression in wild-type and deltadosR strains following 30 min standing. Fifty-two genes were significantly up-regulated, and 19 genes were down-regulated. These included genes that had previously been reported as being part of the dosR regulon, and also some novel ones.
Assuntos
Regulação Bacteriana da Expressão Gênica/fisiologia , Mycobacterium tuberculosis/genética , DNA Bacteriano/genética , Etanol/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Genes Bacterianos/genética , Peróxido de Hidrogênio/farmacologia , Técnicas In Vitro , Mycobacterium tuberculosis/efeitos dos fármacos , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , S-Nitrosoglutationa/farmacologiaRESUMO
The ability to convert androgen to estrogen (aromatization) is a constant feature of gonadal and neural tissues in all major vertebrate groups. In experiments reported here, the existence of this pathway was investigated in the protochordate amphioxus (Branchiostoma lanceolatum). Following incubation with [3H]19-hydroxyandrostenedione, gonadal homogenates contained authentic estrone and estradiol-17 beta, as determined by derivative formation and recrystallization to constant specific activity. Cephalic ("brain") and other segments were aromatase negative. The results indicate that a potential for estrogen biosynthesis in the gonads predates that in other tissues and arises prior to the evolution of true vertebrates.
