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.     

蒽环类抗生素4137的鉴别

链霉菌SIA-73-4137能产生一系列抗肿瘤蒽环类抗生素.将其用酸水解,分析水解后配基的质谱和TLC结果,证明为洋红霉酮和13-二氢洋红霉酮;糖部分则含有柔红糖胺.     

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.     

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。     

Phylogenetic analysis and antimicrobial activities of Streptomyces isolates from mangrove sediment

The phylogeny of members of Streptomyces bacteria isolated from mangrove sediments in the Manakudi estuary near the Arabian Sea, India, was analyzed in the present study. Among the 35 different isolates, five organisms, JS-9, JS-11, JS-12, JS-13 and JS-20, exhibited potent antimicrobial effects against methicillin-resistant Staphylococcus aureus (clinical isolate) and methicillin-susceptible S. aureus MTCC 3160 and Salmonella typhi MTCC 733; all other isolates displayed intermediate antimicrobial effects. RFLP analysis of HaeIII and BstUI double-digested 16S rRNA gene fragments of the isolates were distinguished into 20 distinct RFLP types, with the genetic similarity coefficient varying from 0.57 to 0.97. On average, 17 RFLP markers were observed from approximately 50 to 350 bp size and all the RFLP types showed significant genetic polymorphism by clustering into three major clusters. Phylogenetic analysis showed that the 20-member Streptomyces isolates were divided into three major clusters and they shared 97.2-99.8% sequence identity to the 16S rRNA gene sequences of the Streptomyces taxons of marine origin. The distribution of the isolates revealed that the distinct Streptomyces groups were clustered in the phylogenetic tree and there was a good correlation between the diversity of the antimicrobial phenotype and that of the 16S rRNA gene.     

菌株Streptomyces capillispiralis 1070代谢产物的抗肿瘤机制

目的考察菌株Streptomyces capillispiralis 1070的代谢产物抑制肿瘤细胞A549增殖的作用机制。方法采用MTT法考察菌株Streptomyces capillispiralis 1070的活性代谢产物对A549细胞增殖的抑制作用,采用吖啶橙活细胞染色荧光显微镜观察法、罗丹明123活细胞染色流式细胞检测技术及扫描电镜技术、透射电镜技术观察A549细胞增殖受到抑制后的各种变化。采用全波长扫描与Molish反应对活性物质的成分做初步判断。结果该活性物质可使A549细胞存活率降低至25.79%,可使A549细胞线粒体膜电位明显下降,能使A549细胞胞浆内出现酸性自噬泡,但细胞膜结构完整、无细胞内容物外漏。结论推测该活性物质是通过诱导细胞自噬而发挥其抗肿瘤作用。菌株Streptomyces capillispiralis 1070的活性代谢产物为多糖类物质。     

氮离子注入土霉素产生菌的诱变育种

目的获得土霉素产生菌的高产菌株,提高发酵单位。方法用土霉素产生菌龟裂链霉菌经分离纯化的2810#菌株的分生孢子作处理样品,使用发射能量为15×103eV的氮离子束对其进行诱变处理,氮离子的注入剂量为每平方厘米注入2.0×1015个离子,分生孢子死亡率为98.2%。结果诱变处理后经摇瓶筛选得到1082#高产菌种,其摇瓶发酵单位提高11.2%,投入发酵生产后平均发酵单位提高8.9%。结论氮离子注入方法对提高龟裂链霉菌的产量正向突变频率有明显效果。     

黄直丝链霉菌生产的新的细胞周期抑制剂(-)-脱水亚胺环己酮和l-亚胺环己酮

采用tsFT210细胞的流式细胞术活性筛选模型,通过活性跟踪分离,从黄直丝链霉菌18522发酵物中分离得到两个具有细胞周期抑制活性的化合物,并根据波谱数据和理化性质分别鉴定为(-)-脱水亚胺环己酮(1)和l-亚胺环己酮(2).活性测试结果表明,1和2将tsFT210细胞的细胞周期抑制在G0/G1期,最低有效浓度分别为23.8 μmol/L(1)和10.8 nmol/L(2).化合物1为新天然产物,也是新的亚胺环己酮类细胞周期抑制剂.     

云南美登木共生放线菌菌株CS产生的新多羟基环己烷衍生物

从云南美登木共生放线菌菌株(Streptomyces sp.)CS的发酵产物中分离得一个新的多羟基环己烷衍生物,并通过波谱学特征鉴定化合物的结构为1-isobutyroxymethyl cyclohex-1(6)-ene-2,3,4,5-tetrol-2-isobutyrate.     

复合诱变筛选avermectins高产菌株

由Streptomyces avermitilis初始菌株经过自然分离可以得到三种不同类型的菌株，即灰色粉末型、白色和光秃型。其中灰色粉末型产素水平最高，摇瓶发酵效价达到6835．1μg／ml，B1组分达到56．3％。经过紫外线和亚硝基胍对初始菌株的孢子的诱变及对其原生质体的诱变再生。并且经过异亮氨酸和链霉素的定向筛选，得到的高产菌株摇瓶发酵效价达到8542．9μg／ml，B。组分达到64．9％；同时通过对高产菌株进行传代培养检验其传代稳定性，结果表明，传代3代后，菌株开始退化，并且其发酵效价有比较显著的下降。