Activation of anthrachamycin biosynthesis in Streptomyces chattanoogensis L10 by site-directed mutagenesis of rpoB / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Genome sequencing projects revealed massive cryptic gene clusters encoding the undiscovered secondary metabolites in Streptomyces. To investigate the metabolic products of silent gene clusters in Streptomyces chattanoogensis L10 (CGMCC 2644), we used site-directed mutagenesis to generate ten mutants with point mutations in the highly conserved region of rpsL (encoding the ribosomal protein S12) or rpoB (encoding the RNA polymerase β-subunit). Among them, L10/RpoB (H437Y) accumulated a dark pigment on a yeast extract-malt extract-glucose (YMG) plate. This was absent in the wild type. After further investigation, a novel angucycline antibiotic named anthrachamycin was isolated and determined using nuclear magnetic resonance (NMR) spectroscopic techniques. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis and electrophoretic mobility shift assay (EMSA) were performed to investigate the mechanism underlying the activation effect on the anthrachamycin biosynthetic gene cluster. This work indicated that the rpoB-specific missense H437Y mutation had activated anthrachamycin biosynthesis in S. chattanoogensis L10. This may be helpful in the investigation of the pleiotropic regulation system in Streptomyces.

Sanitary Clearance of Huaneng Qiaoqi Reservoir Bottom in Sichuan / 环境与健康杂志

Objective To assess the result of the sanitary clearance of Huaneng Qiaoqi reservoir bottom.Methods According to related standards and regulations,the sanitary clearance of Huaneng Qiaoqi reservoir bottom was conducted and the result was assessed in Oct.2006.Results 14 360 m~2 farm,417 excrement pits,390 latrines,1 599 graves were sanitarily cleaned. Deratization was carried out in reservoir bottom with Chinese area of 4 878 mu,rat density met the standard(

A biological treatment technique for wool textile

A biological treatment technique for wool textile was carried out by enzymes degradation coupled with H2O2 oxidation. The results demonstrated that the technique had ideal effects on wool textile such as better softness, plump and less loss of bursting stress. Because of mild reaction conditions, less textile damage and less environmental pollution, this technique for wool textile treatment could have promising prospect.

Spatio-temporal expression of the pathway-specific regulatory gene redD in S. coelicolor / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Confocal laser scanning microscopy was used to observe the spatio-temporal expression of the pathway-specific gene redD during S. coelicolor cell cultivation. The corresponding mutant S. coelicolor lyqRY1522 carrying redD::eyfp in the chromosome was constructed. The temporal expression results of the fusion protein during submerged cultivation demonstrated that expression of redD began in the transition phase, continuing through the exponential growth phase to the stationary phase, and reached maximum in the stationary phase. On the other hand, redD was expressed only in substrate mycelia during solid-state culture, while aerial mycelia remained essentially non-fluorescent throughout culture. Results demonstrated that the expression pattern of redD coincides with that of the biosynthesis of the antibiotics during culture, revealing a direct correlation between the spatio-temporal distribution of regulatory gene expression and second metabolism.

SCREENING MICROBIAL HERBICIDES FROM WEED DRB / 微生物学通报

By using enrichment media NPC and CVP, 792 strains of Pseudomonas and 515 strains of Erwinia were isolated from the rhizosphere of Digitaria adscendens (H. B. K.) Hem and Setaria vindis (L.) Beanv. Following which, experiments of antimetabolic test with E. coli, seed emergence controlling of S. viridis, herbicidal activity and security with green grass were carried out to select the desired bacteria. As the result, the selected strain, S7, could wholly control the seed emergence of S. viridis without any harm to the two tested green grass. And more, S7 promoted the seed emergence of Festuca arundinacea slightly. In spite of the comparatively low corrected mortality (56. 7%) of S7 after emergence of S. viridis, Selecting of microbial herbicides from weed DRB is thought to be more prospective.