http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Lee, Eun‐,Jin,Karoonuthaisiri, Nitsara,Kim, Hyo‐,Sub,Park, Joo‐,Hong,Cha, Chang‐,Jun,Kao, Camilla M.,Roe, Jung‐,Hye Blackwell Science Ltd 2005 Molecular microbiology Vol.57 No.5
<P><B>Summary</B></P><P>The differentiating bacterium <I>Streptomyces coelicolor</I> harbours some 66 sigma factors, which support its complex life cycle. σ<SUP>B</SUP>, a functional homologue of σ<SUP>S</SUP> from <I>Escherichia coli</I>, controls both osmoprotection and differentiation in <I>S. coelicolor</I> A3(2). Microarray analysis revealed σ<SUP>B</SUP>‐dependent induction of more than 280 genes by 0.2 M KCl. These genes encode several sigma factors, oxidative defence proteins, chaperones, systems to provide osmolytes, cysteine, mycothiol, and gas vesicle. σ<SUP>B</SUP> controlled induction of itself and its two paralogues (σ<SUP>L</SUP> and σ<SUP>M</SUP>) in a hierarchical order of σ<SUP>B</SUP>→σ<SUP>L</SUP>→σ<SUP>M</SUP>, as revealed by S1 mapping and Western blot analyses. The phenotype of each sigma mutant suggested a sequential action in morphological differentiation; σ<SUP>B</SUP> in forming aerial mycelium, σ<SUP>L</SUP> in forming spores and σ<SUP>M</SUP> for efficient sporulation. σ<SUP>B</SUP> was also responsible for the increase in cysteine and mycothiol, the major thiol buffer in actinomycetes, upon osmotic shock, revealing an overlap between protections against osmotic and oxidative stresses. Proteins in <I>sigB</I> mutant were more oxidized (carbonylated) than the wild type. These results support a hypothesis that σ<SUP>B</SUP> serves as a master regulator that triggers other related sigma factors in a cascade, and thus regulates differentiation and osmotic and oxidative response in <I>S. coelicolor</I>.</P>