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Behnam Nazari Michihiko Kobayashi Akihiro Saito Azam Hassaninasab Kiyotaka Miyashita Takeshi Fujii 《Applied and environmental microbiology》2013,79(2):707-713
Microarray analyses revealed that the expression of genes for secondary metabolism together with that of primary metabolic genes was induced by chitin in autoclaved soil cultures of Streptomyces coelicolor A3(2). The data also indicated that DasR was involved in the regulation of gene expression for chitin catabolism, secondary metabolism, and stress responses. 相似文献
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Rigali S Nothaft H Noens EE Schlicht M Colson S Müller M Joris B Koerten HK Hopwood DA Titgemeyer F van Wezel GP 《Molecular microbiology》2006,61(5):1237-1251
Members of the soil‐dwelling, sporulating prokaryotic genus Streptomyces are indispensable for the recycling of the most abundant polysaccharides on earth (cellulose and chitin), and produce a wide range of antibiotics and industrial enzymes. How do these organisms sense the nutritional state of the environment, and what controls the signal for the switch to antibiotic production and morphological development? Here we show that high extracellular concentrations of N‐acetylglucosamine, the monomer of chitin, prevent Streptomyces coelicolor progressing beyond the vegetative state, and that this effect is absent in a mutant defective of N‐acetylglucosamine transport. We provide evidence that the signal is transmitted through the GntR‐family regulator DasR, which controls the N‐acetylglucosamine regulon, including the pts genes ptsH, ptsI and crr needed for uptake of N‐acetylglucosamine. Deletion of dasR or the pts genes resulted in a bald phenotype. Binding of DasR to its target genes is abolished by glucosamine 6‐phosphate, a central molecule in N‐acetylglucosamine metabolism. Extracellular complementation experiments with many bld mutants showed that the dasR mutant is arrested at an early stage of the developmental programme, and does not fit in the previously described bld signalling cascade. Thus, for the first time we are able to directly link carbon (and nitrogen) metabolism to development, highlighting a novel type of metabolic regulator, which senses the nutritional state of the habitat, maintaining vegetative growth until changing circumstances trigger the switch to sporulation. Our work, and the model it suggests, provide new leads towards understanding how microorganisms time developmental commitment. 相似文献
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As with most amino acid biosynthetic pathways in streptomycetes, enzymes of arginine biosynthesis inStreptomyces coelicolor show only slight derepression in minimal medium without, as opposed to with, exogenous arginine. However, when an arginine auxotroph was cultured in limiting arginine, ornithine carbamoyltransferase (OCT) activities rose by as much as 100-fold. The response was not due to a general starvation effect. To elucidate the repression-derepression mechanism, a DNA fragment containing the upstream region of the previously isolatedS. coelicolor argCJB cluster was cloned into a multicopy vector and transformed into wild-typeS. coelicolor; a slight transient derepression of OCT was observed in minimal medium without, though not with, added arginine, consistent with titration by the insert of a negatively acting macromolecule such as a repressor. A sub-fragment carrying the 5′ end ofargC and the region immediately upstream showed specific binding, in mobility shift assays, to purified AhrC, the repressor/activator of genes of arginine metabolism inBacillus subtilis. It is therefore likely that inS. coelicolor, expression of arginine biosynthesis genes is controlled by a protein homologous to the well-characterisedB. subtilis andEscherichia coli repressors. 相似文献
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Introduction of the foreign transposon Tn4560 in Streptomyces coelicolor leads to genetic instability near the native insertion sequence IS1649 总被引:1,自引:1,他引:0
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We report an altered pattern of genetic instability for Streptomyces coelicolor when the bacterium harbored a foreign transposon, Tn4560. Deletions, amplifications, and circularizations of the linear 8.7-Mb chromosome occurred more frequently at sites adjacent to native insertion elements, notably IS1649. In contrast, deletions, amplifications, and circularizations of a wild-type strain happened at heterogeneous sites within the chromosome. In 50 strains examined, structural changes removed or duplicated hundreds of contiguous S. coelicolor genes, altering up to 33% of the chromosome. S. coelicolor shows a bias toward one type of genetic instability during this particular assault from the environment, the invasion of foreign DNA. 相似文献
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Bohdan Bilyk Stephen Weber Maksym Myronovskyi Oksana Bilyk Lutz Petzke Andriy Luzhetskyy 《Applied microbiology and biotechnology》2013,97(1):351-359
We report here the in vivo expression of the synthetic transposase gene himar1(a) in Streptomyces coelicolor M145 and Streptomyces albus. Using the synthetic himar1(a) gene adapted for Streptomyces codon usage, we showed random insertion of the transposon into the streptomycetes genome. The insertion frequency for the Himar1-derived minitransposons is nearly 100 % of transformed Streptomyces cells, and insertions are stably inherited in the absence of an antibiotic selection. The minitransposons contain different antibiotic resistance selection markers (apramycin, hygromycin, and spectinomycin), site-specific recombinase target sites (rox and/or loxP), I-SceI meganuclease target sites, and an R6Kγ origin of replication for transposon rescue. We identified transposon insertion loci by random sequencing of more than 100 rescue plasmids. The majority of insertions were mapped to putative open-reading frames on the S. coelicolor M145 and S. albus chromosomes. These insertions included several new regulatory genes affecting S. coelicolor M145 growth and actinorhodin biosynthesis. 相似文献