Streptomyces: a superior source for cholesterol oxidase used in serum cholesterol assay.

The present study compared three cholesterol oxidase sources (Nocardia, Streptomyces, and Pseudomonas sps.) for serum cholesterol assay. We found cholesterol oxidase isolated from Streptomyces was superior than those isolated from Nocardia and Pseudomonas sps. Performances of the reagent contained Streptomyces cholesterol oxidase was excellent and comparable to the performances obtained from reagent contained Nocardia cholesterol oxidase. Moreover, the reagent containing Streptomyces cholesterol oxidase had the lowest cost and had the longest shelf-life ($U.S. 0.17/mL, 10 weeks) compared to the reagent contained Nocardia ($U.S. 0.50/mL, 8 weeks) or Pseudomonas ($U.S. 0.20/mL, 6 weeks) cholesterol oxidase.     

红霉素链霉菌遗传控制的研究 2.红霉素链霉菌耐前体耐红霉素高产菌株的筛选

利用长波紫外线和8-甲氧基补骨脂素光敏化物质诱变处理红霉素链霉菌14-74,在含有红霉素或和前体的培养基中,筛选得到了红霉素高产变株。在含有红霉素2万μg/ml 的种子培养基中,筛得活性提高6.2%的耐性变株;在含有6%正丙醇的种子培养基中,得到活性提高12.4%的耐性变株。将耐红霉素3万μg/ml 的变株进一步用长波紫外线诱变处理,在含有5%正丙醇的种子培养基中进行筛选,得到耐红霉素和正丙醇,活性提高19.1%的变株。     

H n.m.r. spectrum from the flexible N-terminal segment of Streptomyces subtilisin inhibitor

The ¹H n.m.r. spectrum of Streptomyces subtilisin inhibitor shows a limited number of unusually sharp signals at room temperature. Some of these signals are assigned uniquely to protons of the side chains of the N-terminal segment, Aspl-Ala2-Pro3-Ser4-Ala5-Leu6-Tyr7-based on experiments of spin decoupling, pH titration, and enzymatic cleavage of the protein. Quantitative examination of these signals indicates that the N-terminal end of this protein is heterogeneous in that the protein contains a considerable fraction whose sequence starts with Ala2 rather than with Asp1. The pK_a values for the amino groups of Asp1 and Ala2 exposed at the N-terminus are determined to be 8.9 ± 0.4 and 9.0 ± 0.1, respectively. Furthermore, examination of the line-widths of the methyl proton resonances of Ala2 and Ala5 residues indicates that the N-terminal peptide segment is free and undergoes rapid segmental motions in the order of 10^?9s.     

Purification and biochemical properties of phospholipase d (PLD57) produced by<Emphasis Type="Italic">Streptomyces</Emphasis> sp. CS-57

Streptomyces sp. CS-57, which was isolated from Korean soil, was found to produce phospholipase D (PLD57) as an extracellular enzyme when cultured in medium containing 2% glucose, 1.5% yeast extract, 0.5% trypton, and 0.1% calcium carbonate at 28 degrees C, and 160-rpm. PLD57 was purified using Sepharose CL-6B column chromatography, and DEAE-Sepharose CL-6B ion exchange column chromatography. The specific activity of the purified enzyme increased 6.7 fold with 3% recovery. The purified enzyme was then analyzed using 12% SDS-PAGE, which revealed that the molecular mass of the purified enzyme was 55 kDa. PLD57 showed both hydrolytic (H) and transphosphatidylation (T) activity, and the optimum temperatures of these activities were found to be 45 degrees C and 35 degrees C, respectively. Similarly, both of these activities were found to be optimal at a pH of 7.5. In addition, even after being heat treated at 45 degrees C for up to 2 h, the enzyme activity remained at 100%, and the H-activity was found to be stable at a pH of 6 to 8. Further, enzyme activity occurred in the presence of EDTA, indicating that metal ions are not required for their activity, although some metal ions did marginally increase the activity. Enzyme activity also increased by 75% in the presence of Triton-X 100 at a concentration of 0.375 %; however, none of the other detergents evaluated in this study were found to enhance enzyme activity.     

一株新种链霉菌菌丝体次生代谢产物的研究

目的 研究一株新种链霉菌（Streptomyces pleomorphus sp. nov.）菌丝体甲醇提取物的化学成分。方法 采用硅胶柱色谱、凝胶柱色谱、制备HPLC方法进行分离,利用理化性质及波谱数据分析结合文献对照确定化合物的结构。结果 从S. pleomorphus sp. nov.菌丝体的甲醇提取物中分离得到12个已知化合物,分别鉴定为teleocidin B2（1）、teleocidin B3（2）、12-齐墩果烯-3,22,24-三醇（3）、胸腺嘧啶脱氧核苷（4）、尿嘧啶脱氧核苷（5）、尿嘧啶（6）、3-甲基哌嗪-2,5-二酮（7）、O-α-D-葡萄吡喃糖乙醇苷（8）、&;#61537;O-α-L-阿拉伯呋喃糖乙醇苷（9）、邻氨基苯甲酸（10）、4-氨基-4-甲基-戊-2-酮（11）、（Z）-13-二十二烯酸（12）。结论 12个化合物均为首次从S. pleomorphus sp. nov.代谢产物中分离得到。     

纳塔尔链霉菌产纳他霉素发酵条件的优化

采用Plackett-Burman设计、最陡爬坡试验与响应面设计相结合的方法对纳塔尔链霉菌(Streptomyces natalensis)SIPI-120620产纳他霉素的发酵条件进行了优化.结果表明,培养基中的玉米淀粉、葡萄糖和NaC1是影响纳他霉素产量的关键因子.优化后的培养条件为:玉米淀粉70g/L、葡萄糖10.7g/L、黄豆饼粉15g/L、酵母粉20g/L、NaCll.3g/L、碳酸钙2g/L及初始pH6.5.此试验条件下,纳他霉素产量达到4.09g/L,比原培养条件提高了1.86g/L倍.     

Three new compounds from soil actinomycete Streptomyces albospinus 15-4-2

Three new compounds, 2-methyl-2,5,6-bornantriol (1), 4,4′-(3-hydroxypropane-1,1-diyl)diphenol (2), and 7-(4-methoxybenzyl)-4,5,6,7-tetrahydro-1,3-oxazepine-5,6-diol (3), were isolated from the fermentation broth of the soil actinomycete Streptomyces albospinus 15-4-2. Their structures were completely elucidated using the combination of 1D, 2D NMR techniques (COSY, HMQC, HMBC, and ROESY), and HR-ESI-MS analysis. None of the compounds 1–3 showed any inhibitory effect on Fusarium oxysporum f.sp. cubense race 4.     

A new staurosporine analog from Actinomycetes Streptomyces sp. (172614)

A new staurosporine analog, 10′-{5″-[(methoxycarbonyl)amino]-2″-methyl}-phenylaminocarbonylstaurosporine (1), together with staurosporine (2), was obtained from the culture broth of Actinomycetes Streptomyces sp. (172614). Their structures were elucidated by comprehensive spectroscopic analysis including UV, MS, NMR, and CD spectra. Pharmacological experiments revealed that 1 and 2 showed significant cytotoxicity against human colon tumor cell HCT-116.     

A new trichostatin analog from Streptomyces sp. CPCC 203909

A new trichostatin analog (1) and two known analogs (2, 3) have been isolated from the rice fermentation of the Streptomyces sp. CPCC 203909. Their structures were determined by spectroscopic and chemical methods. The absolute configurations of 1 were assigned by Marfey's method, combined with comparing the NMR and circular dichroism spectroscopic data of 2 and 3. Compound 1 showed cytotoxicity against human embryonic kidney 293 cell line with IC₅₀ value of 39.2 μM.     

Susceptibility of local Agrobacterium tumefaciens strains to streptomycetes isolates from Jordan soils

Five strains of Agrobacterium tumefaciens were isolated and characterized from 12 different plant tumors. The susceptibility of these phytopathogens to antibiotics and to soil Streptomyces isolates was tested. Among the 90 Streptomyces isolates, only 12 were able to inhibit the growth of at least one A. tumefaciens strain. Four strains of A. tumefaciens were susceptible to streptomycin and cefotaxime. In addition, Streptomyces 404 strain was able to inhibit the growth of four strains of the Agrobacterium pathogens with an inhibition zone diameter ranged between 10 and 16 mm. The strong inhibitory effects of Streptomyces 404 strain on A. tumefaciens suggest the use of this strain as a promising agent to control crown gall disease.