埃坡霉素高产菌株的选育

采用紫外-亚硝酸盐复合诱变法对纤维堆囊菌(Sorangium cellulosum)ATCC 15384进行诱变,结合红霉素抗性筛选,筛得一株遗传稳定的埃坡霉素高产菌株纤维堆囊菌UNl6H127,埃坡霉素A(Epo A)和埃坡霉素B(Epo B)的产量为289.9和25.14μg/L,总产量(EpoA+Epo B,315.04μg/L)是出发菌株的23.8倍.     

硫酸二乙酯对纤维堆囊菌的诱变育种

本文以纤维堆囊菌(Sorangium cellulosm)ATCC15384的紫外突变株为出发菌株,用硫酸二乙酯(DES)进行化学诱变,最终得到了埃博霉素A和B的产量分别为13.93和6.82mg/L的高产菌株,分别比原始菌株提高了6.61和3.04倍.说明使用DES诱变可以显著提高埃博霉素产量.     

基因组重组技术选育埃博霉素B高产菌株

目的 用基因重组技术选育埃博霉素高产菌株.方法 本研究首先从不同生境中分离筛选到4株能产生埃博霉素B的纤维堆囊菌,以这些野生菌株作为Genome shuffling递归原生质体融合出发菌株.结果 通过五轮基因组重组成功选育到了3株遗传稳定的高产埃博霉素B重组菌株,其中一株重组菌株So F5-09的埃博霉素B产量达到了15.8mg/L,比原始出发菌株So 07-9埃博霉素B产量提高了35.1倍.结论 本研究证明使用野生菌株作为Genome shuffling递归原生质体融合出发菌株也能有效提高目标代谢产物的产量.     

复合诱变法选育普那霉素高产菌株

以始旋链霉菌(Streptomyces pristinaespiralis)ZP2为出发菌株,经紫外线(UV)、亚硝基胍(NTG)复合诱变,并结合普那霉素抗性突变株的理化筛选,选育到一株高产突变菌株UN2056,其普那霉素产量达到1490 mg/L,比出发菌株提高了45.7%.传代试验表明该高产突变菌株的高产性能遗传特性稳定.高产突变株UN2056在5 L发酵罐中进行发酵试验,其平均发酵产量达到1645 mg/L,比出发菌株提高了60.8%.     

新型常压室温等离子体-紫外复合诱变选育埃莎霉素I高产菌株#br#

目的 通过对埃莎霉素Ⅰ产生菌WSJ-IA进行诱变选育研究,以期获得埃莎霉素Ⅰ高产菌株。方法 使用多功能等离子体诱变系统(multifunctional plasma mutagenesis system, MPMS)对出发菌株的孢子进行等离子体和紫外复合诱变,设定不同的诱变时间处理孢子悬液,通过致死率确定合适的诱变条件,利用突变株摇瓶发酵效价筛选出正突变菌株。结果 在MPMS射频功率为100W,处理距离5mm,气体流量12.5SLM,等离子体-紫外辐射时间为50s时,菌株致死率为96.08%。在此诱变条件下,以突变株的初筛效价为指标的突变率、正突变率分别达到63.96%和22.52%,复筛效价是出发菌株1.5倍以上的有5株,占复筛菌株的9%。最终筛选出一株发酵单位比出发菌株提高221%、埃莎霉素Ⅰ组分含量提高192%的正突变株IA-425。42L自动发酵罐发酵结果表明,该菌株埃莎霉素Ⅰ产量达到(2000±200)μg/mL左右。结论 新型等离子体复合紫外诱变方式,可有效提高菌株的埃莎霉素Ⅰ发酵产量和组分含量。这为埃莎霉素Ⅰ的大规模发酵和临床前研究奠定了良好基础。     

糖肽类抗生素A40926B产生菌的培养基优化及菌种选育

以A40926 B产生菌野野村放线菌SIPI-D-30为出发菌株,通过UV诱变及乙酸钠和甘氨酸抗性平板筛选,获得A40926 B产量提高的突变株SIPI-U-157。经优化,确定摇瓶发酵培养基(g/L)为:葡萄糖5.0、麦芽糊精30.0、可溶性淀粉10.0、玉米淀粉30.0、大豆蛋白胨5.0、肉蛋白胨10.0、酵母浸粉5.0、冷榨黄豆饼粉10.0、棉籽饼粉5.0、L-缬氨酸1.0,发酵培养7 d,突变株的A40926 B发酵单位为893 mg/L。该突变株在5 L发酵罐中培养180 h,A40926 B的产量最高为583 mg/L。     

微波诱变及添加氯化镧筛选阿扎霉素B高产菌株

目的 拟通过微波诱变和添加氯化镧对阿扎霉素B产生菌N98-1634进行选育,获得高产菌株.方法 对菌株进行40～240s的微波诱变,采用金黄色葡萄球菌抑菌圈法获得初筛通过株,并进行HPLC复筛获得高产菌株;在高产菌株发酵培养基中加入5～30mg/L的氯化镧考查其对阿扎霉素B合成的影响.结果 通过微波诱变选出l株阿扎霉素B产量达到945.0μg/mL的突变菌株MW-638,较出发菌株N98-1634的752.4μg/mL提高了25.6％,随后经过添加15mg/L氯化镧阿扎霉素B单位最终达到1413.8μg/mL.结论 微波诱变对提高菌株N98-1634阿扎霉素B发酵单位效果明显,诱变菌株添加适量氯化镧可以显著提高其产量.     

埃博霉素高产菌株的诱变筛选

目的:探讨埃博霉素高产菌株的诱变筛选方法与效果.方法:选择原始菌株DES35 进行原始培养,在培养中进行硫酸二乙酯化学诱变筛选.结果:筛选到了6 株产量有所提高的突变株.高产菌株的埃博霉素A 与B 的平均产量与诱变前都有明显提高(P＜0.05).结论:埃博霉素高产菌株的硫酸二乙酯诱变筛选能使埃博霉素产量稳定提高,为埃博霉素生产提高了良好的菌株资源.     

达托霉素产生菌前体物耐受选育及其流加补料发酵

目的 通过对达托霉素产生菌进行诱变选育,以及前体物补料发酵方式提高达托霉素的产量。方法 采用常压室温等离子体(atmospheric and room temperature plasma, ARTP)技术对玫瑰孢链霉菌进行诱变,以癸酸铵和甘氨酸耐受作为选择压力进行菌株筛选,在摇瓶和100L发酵罐上进行癸酸铵流加补料试验确定最佳的发酵工艺。结果 经诱变选育获得1株突变株FIM-D1568摇瓶效价达到380mg/L,发酵单位较出发菌株提高了35.7%;通过优化100L发酵罐流加补料癸酸铵溶液工艺,使达托霉素发酵效价达到2276mg/L。结论 以ARTP为诱变源,甘氨酸及癸酸铵耐受性为选择性压力,可以快速筛选获得达托霉素高产菌;高产突变菌株在流加补料发酵工艺上优良性状得以发挥,发酵效价大幅提高。     

纳他霉素高产菌株的链霉素抗性选育及其发酵工艺的优化

用紫外线对纳他霉素(Natamycin)产生菌褐黄孢链霉菌(Streptomyces gilvosporeus)ATCC13326菌株孢子进行诱变处理后，利用链霉素抗性突变选育得122株链霉素抗性突变株。其中纳他霉素产量高于出发菌株的有13株。突变株SG-56的生产能力达到出发菌株的146％，研究了其发酵性能，优化了培养基组成和发酵工艺条件，纳他霉素产量为2．81g／L，较出发菌株产量提高了170％。     

Studies on the biosynthesis of epothilones: the biosynthetic origin of the carbon skeleton

The biosynthetic origin of the epothilone skeleton was studied by the incorporation of 13C and radioactively labeled precursors by Sorangium cellulosum So ce90. The carbon atoms are derived from acetate, propionate, the methyl group of S-adenosyl-methionine, and cysteine which also introduces the sulfur and nitrogen atoms. Epothilone biosynthesis starts with the formation of the thiazole part from acetate and cysteine. The incorporation of acetate or propionate units results in the formation of epothilones A and B, respectively. To introduce the epoxide function of epothilones A and B molecular oxygen is used.     

纤维堆囊菌菌株So0157-2中的四个天然埃博霉素衍生物(英文)

从纤维堆囊菌菌株So0157-2发酵吸附树脂的提取物中分离得到四个天然埃博霉素衍生物,包括两个14元环埃博霉素L(1)和L1(2),以及两个环氧环打开的埃博霉素A(3)和B(4)。并根据核磁共振和质谱等方法鉴定了它们的结构。这四个化合物都是首次作为天然产物从该菌株中分离得到,也是首次对化合物的数据进行全指定。     

Discovery and development of the epothilones : a novel class of antineoplastic drugs

The epothilones are a novel class of antineoplastic agents possessing antitubulin activity. The compounds were originally identified as secondary metabolites produced by the soil-dwelling myxobacterium Sorangium cellulosum. Two major compounds, epothilone A and epothilone B, were purified from the S. cellulosum strain So ce90 and their structures were identified as 16-member macrolides. Initial screening with these compounds revealed a very narrow and selective antifungal activity against the zygomycete, Mucor hiemalis. In addition, strong cytotoxic activity against eukaryotic cells, mouse L929 fibroblasts and human T-24 bladder carcinoma cells was observed. Subsequent studies revealed that epothilones induce tubulin polymerization and enhance microtubule stability. Epothilone-induced stabilisation of microtubules was shown to cause arrest at the G2/M transition of the cell cycle and apoptosis. The compounds are active against cancer cells that have developed resistance to taxanes as a result of acquisition of beta-tubulin overexpression or mutations and against multidrug-resistant cells that overexpress P-glycoprotein or multidrug resistance-associated protein. Thus, epothilones represent a new class of antimicrotubule agents with low susceptibility to key tumour resistance mechanisms.More recently, a range of synthetic and semisynthetic epothilone analogues have been produced to further improve the adverse effect profile (or therapeutic window) and to maximize pharmacokinetic and antitumour properties. Various epothilone analogues have demonstrated activity against many tumour types in preclinical studies and several compounds have been and still are being evaluated in clinical trials. This article reviews the identification and early molecular characterization of the epothilones, which has provided insight into the mode of action of these novel antitumour agents in vivo.     

均匀设计法优化埃博霉素树脂原位提取条件

采用均匀设计(U_(16)~3)方案考察树脂提取条件对纤维堆囊菌UNH127产生埃博霉素的影响.结果埃博霉素树脂原位提取的最佳工艺条件为:树脂加入时间12.9h,加入量6.4%,培养时间约8d.上述条件下,埃博霉素产量为2.105 2mg/L,与预测值(2.127 2 mg/L)的误差为1.03%.     

Epothilones: a novel class of non-taxane microtubule-stabilizing agents

The epothilones are a novel class of non-taxane microtubule-stabilizing agents obtained from the fermentation of the cellulose degrading myxobacteria, Sorangium cellulosum. Preclinical studies have shown that the epothilones are more potent than the taxanes and active in some taxane-resistant models. Similar to paclitaxel and other taxanes, the epothilones block cells in mitosis, resulting in cell death. The chief components of the fermentation process are epothilones A and B, with epothilones C and D found in smaller amounts. Trace amounts of other epothilones have also been detected. Pre-clinical studies have shown that epothilone B is the most active form, exhibiting significantly higher antitumor activity than paclitaxel and docetaxel. Several phase I and phase II clinical trials are ongoing with epothilone B and BMS 247550, an epothilone B analog. Preliminary reports indicate these agents are active against human cancers in heavily pre-treated patients. The epothilones appear to be well tolerated, with a side effect profile that is similar to that reported with the taxanes. This article will review some basic aspects of epothilone chemistry and biology, and pre-clinical and preliminary clinical experience with epothilone B and its analog, BMS 247550.     

Epothilones and their analogues - a new class of promising microtubule inhibitors

Epothilones A and B are naturally occurring microtubule depolymerisation inhibitors, which inhibit the growth of human cancer cells in vitro at nanomolar or even sub-nanomolar concentrations. In contrast to paclitaxel (Taxol^®, Bristol-Myers Squibb) epothilones are also active against multi-drug resistant cancer cell lines and epothilone B exhibits potent in vivo antitumour activity against multidrug-resistant tumours. In addition, epothilones A and B have been shown to be active in vitro against cell lines whose paclitaxel-resistance is derived from specific tubulin mutations. Their attractive preclinical profile has made epothilones important lead structures in the search for improved cytotoxic anticancer drugs and hundreds of analogues and derivatives of epothilones have been prepared and biologically characterised over the past four years. While chemical modifications have been reported for almost every position of the epothilone structural framework, the major focus has been on modifications of the epoxide moiety at C-12/C-13, the C-6- position, the ester linkage and the unsaturated heterocyclic side-chain. Several of the compounds thus produced exhibit low nM IC₅₀ values for the inhibition of human cancer cell proliferation and may represent potential development candidates. Currently, two compounds, natural epothilone B and BMS247550, the lactam analogue of epothilone B, are undergoing clinical trials. An additional analogue, epothilone D, also known as deoxyepothilone B, appears to be in late stage preclinical development and may enter clinical trials in the near future.     

Recent developments in the chemical biology of epothilones

Epothilones A and B are naturally occurring microtubule-stabilizers, which inhibit the growth of human cancer cells in vitro at nM or even sub-nM concentrations. In contrast to paclitaxel (Taxol) epothilones are also active against different types of multidrug-resistant cancer cell lines in vitro and against multidrug-resistant tumors in vivo (epothilone B). Their attractive preclinical profile has made epothilones important lead structures in the search for improved cytotoxic anticancer drugs and epothilone B is currently undergoing phase II clinical trials. Numerous synthetic and semi-synthetic analogs have been prepared since the absolute stereochemistry of epothilone B was first disclosed in mid-1996 and their in vitro biological activity has been determined. Apart from generating a wealth of SAR information, these efforts have led to the identification of at least four compounds (in addition to epothilone B), which are currently at various stages of clinical evaluation in humans. This review is first intended to provide a summary of the basic features of the in vitro biological profile of epothilone B, with particular emphasis on recent developments in this area. A second part will outline the most relevant aspects of the epothilone SAR with regard to effects on tubulin polymerization, in vitro antiproliferative activity, and in vivo antitumor activity. This will include a brief discussion of research directed at the determination of the bioactive conformation of epothilones. In a final section, the preclinical profile of those epothilone analogs currently in clinical development will be discussed in greater detail.     

埃博霉素作用机制和临床药理的研究进展

埃博霉素是由纤维堆囊菌分离得到的一类16元大环内酯类抗生素,其具有比紫衫炕类更强的微管稳定作用和抗肿瘤活性,对紫杉烷类耐药的肿瘤细胞仍具有较好的细胞毒性;综述2010年-2012年间关于埃博霉素的产生菌、生物合成和发酵表达、抗肿瘤机制以及临床药理研究的文献资料,并对其研究进展作一分析。     

Epothilone B and its analogs - a new family of anticancer agents

Epothilones are naturally occurring 16-membered macrolides with the ability to promote tubulin polymerization in vitro and to stabilize preformed microtubules against Ca(2+)- or cold-induced depolymerization. In contrast to paclitaxel (Taxol((R))) epothilones are also active in vitro against multidrug-resistant cancer cell lines as well as cell lines whose paclitaxel-resistance is derived from specific beta-tubulin mutations. Based on their attractive in vitro biological profile epothilones have turned into important lead structures in anticancer drug discovery and hundreds of analogs and derivatives of epothilone A and B have been prepared and biologically characterized over the past four years. A number of compounds, including natural epothilone B, deoxyepothilone B, and epothilone B lactam (BMS-247550) have also been reported to exhibit profound in vivo antitumor activity in animal models. Apart from providing a brief summary of the SAR that has emerged from the above in vitro studies, this minireview will largely focus on the biology and chemistry of those analogs for which in vivo antitumor activity has been reported in the literature. Two of these compounds, natural epothilone B and epothilone B lactam (BMS-247550) have advanced to clinical studies in humans.     

The biology and medicinal chemistry of epothilones

Epothilones are naturally occurring 16-membered macrolides with the ability to promote tubulin polymerization in vitro and to stabilize preformed microtubules against Ca(2+)- or cold-induced depolymerization. At the cellular level, interference with microtubule functionality results in potent inhibition of cancer cell proliferation at nM to even sub-nM concentrations. Most significantly, epothilones, unlike paclitaxel (Taxol), are equally active against drug-sensitive and multidrug-resistant cell lines in vitro and epothilone B has also shown potent in vivo antitumor activity in Taxol-resistant human tumor models. Epothilone B is currently undergoing Novartis-sponsored Phase II clinical trials. In addition to naturally occurring epothilones, numerous synthetic and semi-synthetic analogs have been prepared since the absolute stereochemistry of epothilone B was first disclosed in mid-1996 and their in vitro biological activity has been determined. These studies have generated a wealth of SAR data in a remarkably short period of time, given the complexity of the synthetic targets pursued. One of these analogs, BMS-247550, is presently in Phase II clinical trials by Bristol-Myers Squibb. In a first part this review is intended to provide a summary of the basic features of the in vitro biological profile of epothilones A and B, including emerging data on potential cellular epothilone resistance mechanisms. The second and third part will feature a comprehensive discussion of the epothilone SAR as it has emerged from the work of various (industrial and academic) laboratories across the world, including our own, with regard to effects on tubulin polymerization, in vitro antiproliferative activity, and in vivo antitumor activity.