RESUMO
Yeast cells exposed to adverse conditions employ a number of defense mechanisms in order to respond effectively to the stress and sustain a high proliferation rate. It has been shown that several glycolytic enzymes are induced upon heat treatment of yeast. In this work, we used a reporter plasmid construct to study the effects of oxidative stress, induced by the O(*-)(2)-generating compound paraquat (PQ), on the yeast 3-phosphoglycerate kinase gene (PGK) promoter. Our results show that (i) moderate, as opposed to excessive, doses of PQ induce increased stimulation of the PGK promoter, at midlogarithmic phase of growth; and (ii) the thiol antioxidant N-acetylcysteine cancels this stimulatory effect. These observations may represent one aspect of a more general role for glycolysis in maintaining the energy pools of yeast cells under stress.
Assuntos
Paraquat/farmacologia , Fosfoglicerato Quinase/genética , Regiões Promotoras Genéticas/efeitos dos fármacos , Saccharomyces cerevisiae/enzimologia , Acetilcisteína/farmacologia , Clonagem Molecular , Escherichia coli , Temperatura Alta , Cinética , Proteínas Recombinantes/biossíntese , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Superóxidos , beta-Galactosidase/biossíntese , beta-Galactosidase/genéticaRESUMO
Fourteen neo-clerodane diterpenoids have been isolated from the acetone extract of the aerial parts of four species of Teucrium (T.alpestre, T. cuneifolium, T. divarication subsp. villosum, and T. flavum subsp. hellenicum) not previously studied chemically.
