Developmental control of the heat-shock stress regulon in Streptomyces coelicolor

In the differentiating eubacterium Streptomyces coelicolor , nutritional imbalances activate a developmental programme which involves the heat-shock stress regulon. In liquid batch cultures, the growth curve could be separated into four components: rapid growth 1 (RG1), transition (T), rapid growth 2 (RG2) and stationary (S). Patterns of gene expression in cultures subjected to heat shock in various phases were recorded on two-dimensional gels and analysed using advanced statistical methods. The responses of all heat-shock proteins (HSPs) were highly dependent upon the growth phase, thus demonstrating that the four phases of growth were physiologically distinct. For many HSPs, the levels of thermal induction attained were closely related to growth stage-determined levels of synthesis before heat shock, thus supporting the idea that developmental and thermal induction of this stress regulon have common control elements. Cluster analysis identified five groups of HSPs displaying similar kinetics of heat and developmentally induced synthesis, probably reflecting the influence of major regulatory systems. Methods introduced here to analyse the response of groups of genes to multiple simultaneous stimuli should find broad applications to studies of other prokaryotic and eukaryotic regulons.     

The role of NdgR in glycerol metabolism in Streptomyces coelicolor

Bioprocess and Biosystems Engineering - Streptomyces, which produces many pharmaceutical antibiotics and anticancer agents, is a genus of soil-dwelling bacteria with numerous regulators that...     

Proteomic analysis of the GlnR-mediated response to nitrogen limitation in Streptomyces coelicolor M145

GlnR is the global regulator of nitrogen assimilation in Streptomyces coelicolor M145 and other actinobacteria. Two-dimensional polyacrylamide gel electrophoresis analyses were performed to identify new GlnR target genes by proteomic comparison of wild-type S. coelicolor M145 and a ΔglnR mutant. Fifty proteins were found to be differentially regulated between S. coelicolor M145 and the ΔglnR mutant. These spots were identified by nanoHPLC–ESI-MS/MS and classified according to their cellular role. Most of the identified proteins are involved in amino acid biosynthesis and in carbon metabolism, demonstrating that the role of GlnR is not restricted to nitrogen metabolism. Thus, GlnR is supposed to play an important role in the global metabolic control of S. coelicolor M145.     

变铅青链霉菌广谱胁迫蛋白对氧化压力响应的研究

【目的】广谱胁迫蛋白(USP)是一种古老的蛋白家族,在链霉菌属细菌中其功能研究尚未报道。以变铅青链霉菌USP蛋白为对象对其功能进行解析。【方法】使用序列比对的方法分析同源性及保守结构域。纯化USP蛋白,用圆二色谱分析蛋白与环腺苷酸(cAMP)的结合对usp(SLI_7517)进行基因中断。检测野生型和usp基因缺失株对偶氮二甲酰胺造成的氧化压力的耐受能力。使用qPCR荧光定量分析技术,检测野生型菌株与usp缺失株在氧化环境中谷胱甘肽过氧化物酶及巯基过氧化物酶基因转录量的差异。【结果】同源序列分析表明链霉菌属来源的USP蛋白序列相互之间相似性较高,USP-like结构域高度保守。USP蛋白在体外结合cAMP引起CD谱的变化。usp基因缺失株对偶氮二甲酰胺更耐受,同时菌株中谷胱甘肽过氧化物酶基因转录量上升。【结论】变铅青链霉菌中USP蛋白能够结合cAMP。usp参与菌体应对氧化环境的调控,对谷胱甘肽过氧化物酶基因的转录有阻遏作用。     

The dpsA gene of Streptomyces coelicolor: induction of expression from a single promoter in response to environmental stress or during development

The DpsA protein plays a dual role in Streptomyces coelicolor, both as part of the stress response and contributing to nucleoid condensation during sporulation. Promoter mapping experiments indicated that dpsA is transcribed from a single, sigB-like dependent promoter. Expression studies implicate SigH and SigB as the sigma factors responsible for dpsA expression while the contribution of other SigB-like factors is indirect by means of controlling sigH expression. The promoter is massively induced in response to osmotic stress, in part due to its sensitivity to changes in DNA supercoiling. In addition, we determined that WhiB is required for dpsA expression, particularly during development. Gel retardation experiments revealed direct interaction between apoWhiB and the dpsA promoter region, providing the first evidence for a direct WhiB target in S. coelicolor.     

海洋来源链霉菌OUCMDZ-3434中wblA基因的功能

【背景】Streptomyces sp. OUCMDZ-3434分离自山东青岛栈桥浒苔样品,其次级代谢产物Wailupemycin类化合物具有良好的α-糖苷酶抑制活性,但产量很低,影响了其进一步研发。【目的】建立海洋来源链霉菌Streptomyces sp. OUCMDZ-3434菌株的遗传转化系统,通过阻断全局性调控基因wblA探究Wailupemycin类化合物产量变化。【方法】以p SET152为载体,采用大肠杆菌-链霉菌属间接合转移策略建立了Streptomycessp.OUCMDZ-3434的遗传转化方法。采用PCR-Targeting策略构建了wblA基因阻断突变株,通过HPLC分析野生型和突变株发酵产物的差异并对表型差异进行显微形态观察。【结果】建立了Streptomyces sp. OUCMDZ-3434遗传转化系统,构建了wblA基因阻断突变株,与野生株相比,突变株发酵产物中Wailupemycin G产量提高了3倍,同时丧失了产生孢子的能力。【结论】在Streptomycessp.OUCMDZ-3434中wblA对Wailupemycin类化合物生物合成起到了负调控作用,同时参与调控孢子形成,本研究为采用遗传改造策略提高Wailupemycin G产量提供了参考。     

New approach to the genetics of Streptomyces coelicolor

Sermonti, G. (Istituto Superiore di Sanità, Rome, Italy), Milena Bandiera, and Isabella Spada-Sermonti. New approach to the genetics of Streptomyces coelicolor. J. Bacteriol. 91:384-392. 1966.-Mixed cultures of complementary auxotrophic strains of Streptomyces coelicolor A3(2) were preincubated on discs of cellophane on complete medium and were then transferred onto selective media. When one strain was streptomycin-resistant and the other was streptomycin-sensitive, and the transfer medium contained streptomycin, distinct minute tufts of aerial mycelium appeared on the background growth of the mixed culture. They turned out to be heterozygous clones (heteroclones) in which the streptomycin-sensitive allele was, as a rule, missing. The pattern of marker contribution of the streptomycin-sensitive parent to the zygotes was indicative of a continuous structure carrying the hereditary material. A gradual transfer of the donor genome during conjugation was suggested by the progressive completion of the zygotes obtained by increasing preincubation time.