恩拉霉素高产菌株选育的研究#br#

目的 进一步提高恩拉霉素发酵生产水平。方法 对杀真菌链霉菌RN16-7进行ARTP(常压室温等离子体)等离子与庆大霉素复合处理。结果 经大量筛选，得到了恩拉霉素高产突变株RN16-242，其遗传性状稳定，发酵效价达7423u/mL，比出发菌株RN16-7(4703u/mL)提高了57.8%。菌株保存，采用甘油管低温保藏法、沙土管保藏法和冷冻真空干燥保藏法进行了比较，结果是甘油管低温保藏法最好。     

Identification and biocontrol efficacy of Streptomyces miharaensis producing filipin III against Fusarium wilt

A number of bacterial strains were isolated from the internal tissue of Trapa japonica. Of these, strain KPE62302H, which had a 16S rDNA sequence identical to that of Streptomyces miharaensis showed antifungal activity against several plant pathogens. Treatment of seeds with strain KPE62302H induced a significant reduction in the incidence of Fusarium wilt in tomato plants compared with untreated controls. An antifungal substance (FP‐1) was purified from the culture extract of strain KPE62302H using C18 flash and Sephadex LH‐20 column chromatography and reverse phase HPLC. Extensive spectrometric analysis using MS and NMR identified this as filipin III. FP‐1 inhibited the mycelial growth of plant pathogenic fungi such as Alternaria mali, Aspergillus niger, Colletotrichum gloeosporioides, C. orbiculare, Cylindrocarpon destructans, Diaporthe citiri, Fusarium oxysporum at 1–10 μg ml^–1 and also markedly inhibited the development of Fusarium wilt caused by F. oxysporum f.sp. lycopersici in tomato plants by treatment with 10 μg ml^–1 under greenhouse conditions. The efficacy of FP‐1 against Fusarium wilt was comparable to that of the synthetic fungicide benomyl. An egfp ‐tagged strain of KPE62302H confirmed its ability to colonize tomato plants. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Response surface methodology: A non-conventional statistical tool to maximize the throughput of Streptomyces species biomass and their bioactive metabolites

Among diverse actinobacteria, Streptomyces is a renowned ongoing source for the production of a large number of secondary metabolites, furnishing immeasurable pharmacological and biological activities. Hence, to meet the demand of new lead compounds for human and animal use, research is constantly targeting the bioprospecting of Streptomyces. Optimization of media components and physicochemical parameters is a plausible approach for the exploration of intensified production of novel as well as existing bioactive metabolites from various microbes, which is usually achieved by a range of classical techniques including one factor at a time (OFAT). However, the major drawbacks of conventional optimization methods have directed the use of statistical optimization approaches in fermentation process development. Response surface methodology (RSM) is one of the empirical techniques extensively used for modeling, optimization and analysis of fermentation processes. To date, several researchers have implemented RSM in different bioprocess optimization accountable for the production of assorted natural substances from Streptomyces in which the results are very promising. This review summarizes some of the recent RSM adopted studies for the enhanced production of antibiotics, enzymes and probiotics using Streptomyces with the intention to highlight the significance of Streptomyces as well as RSM to the research community and industries.     

海洋放线菌Streptomyces sp.(No.172221)次生代谢产物研究

目的研究一株海洋放线菌Streptomyces sp.(No.172221)的次生代谢产物。方法采用各种色谱方法进行成分分离,综合运用多种波谱学手段确定单体化合物的结构。结果分离到8个化合物,鉴定其结构分别为麦角甾-3β,5α,6β-三醇(1);麦角甾-3β,5α,6β-三醇-3-Ο-β-D葡萄糖苷(2);N-苯甲基氨基甲酸(3);1,3-丙二醇苯乙酸酯(4);环(脯-亮)二肽(5);环(脯-缬)二肽(6);脯氨酸(7)和腺嘌呤核苷(8)。结论化合物1和2为甾体类化合物,其中化合物2为首次从放线菌中分离得到,化合物3、4为新天然产物,化合物5和6为常见的细菌代谢产物环二肽类。     

构建有序排列的除虫链霉菌基因组的柯斯文库用于工业生产菌株的遗传改造

以容纳DNA大片段的柯斯质粒Supercos-1为载体.构建了除虫链霉菌的基因组文库.对约1000个柯斯质粒上插入片段的两端进行测序,并利用全基因组序列的信息,构建了覆盖约91%基因组的有序排列的柯斯文库.利用入λ-Red高效DNA重组和大肠埃希菌-链霉菌接合转移技术,建立了除虫链霉菌的基因组遗传操作系统.运用该系统可以在除虫链霉菌工业菌株中进行高效、精确的基因敲除工作和连续的基因缺失研究,获得可以用来生产多拉菌素的工程菌株.     

天蓝淡红链霉菌SIPI 1482及其突变株的研究：I.发酵过程中 …

用光学显微镜和透射电子显微镜，研究天蓝淡红链霉素ＳＩＰＩ １４８２及其突变株ＳＩＰＩ １４８２－ＮＳ－４在发酵过程中细胞形态和超微结构的变化。发现两者最大的不同在于：亲株能合成柔红霉素，产抗期细胞内含物丰富，但脂肪颗粒较少；突变株不能合成柔红霉素，细胞中含有丰富的脂肪颗粒。由于柔红霉素的生物合成与脂肪酸的合成密切相关，提示超微结构中脂肪颗粒的变化可能与柔红霉素的合成有关。     

始旋链霉菌HCCB2003-8 snaA、snaB和snaC基因的克隆、序列分析及原核表达

以始旋链霉菌（Streptomyces pristinaespiralis）HCCB2003—8的染色体DNA为模板，通过优化PCR条件扩增出FMN还原酶、PII．合酶的基因片段。与文献报道的基因序列做同源比较，snaA和snaB碱基序列分别只有一个碱基的差异，snaC碱基序列完全匹配。将snaA、snaB和snaC的基因片段插入原核表达载体pET30a中，并转化至大肠埃希菌BL21（DE3）。SDS—PAGE结果表明。经IPTG诱导后基因分别得到表达。     

原生质体再生与诱变在硫霉素产生菌选育中的应用

以硫霉素产生菌卡特利链霉菌３５８（Ｓｔｒｅｐｔｏｍｙｃｅｓｃａｔｌｅｙａ３５８）为原始菌株,用原生质体形成与再生结合物理、化学诱变的方法进行菌种选育。在最适条件下原生质体释放浓度和再生率分别为１．６×１０９／ｍｌ和２９．５％。原生质体再生处理后,硫霉素产量变异向正方向移动,筛选到１株ＰＲ－１１７,相对效价提高６０％。分别以菌株ＰＲ－１１７的孢子和原生质体进行紫外线及亚硫酸氢钠诱变,原生质体对诱变剂的敏感性强于孢子,致死率增加,效价分布更分散。原生质体与孢子紫外线诱变正变率分别为１６．５％和９％,亚硫酸氢钠诱变的正变率都为４％。从原生质体紫外线诱变株中筛选到１株ＰＲｕ－３３６,相对效价比原始菌株提高９０％。     

透明颤菌血红蛋白基因(vgb)在阿维链霉菌的整合表达

pHZ1276是透明颤菌血红蛋白基因(vgb)的诱导型表达载体，携带有硫链丝菌素诱导的强启动子PtipA和ФC31int，attP基因使载体整合在染色体上。本研究利用组成型启动子ermP1P2替代pHZ1276上的诱导型启动子PtipA构建了组成型表达血红蛋白基因的质粒pHZ1291。将vgb基因去掉后构建了组成型链霉菌表达载体pHZ1294。将pHZ1276。pHZ1291导人阿维链霉菌(Streptomyces avermitiHs)NRRL8165，所得重组子经Southern杂交验证后，蛋白粗提物经Western杂交和CO结合实验表明vgb基因在该菌中表达出了有活性的VHb蛋白。