东乡野生稻内生放线菌Streptomyces sp. PRh5的全基因组测序及序列分析

【目的】Streptomyces sp. PRh5是从东乡野生稻(Oryza rufipogon Griff.)中分离获得的一株对细菌和真菌都具有较强抗菌活性的内生放线菌。为深入研究PRh5菌株抗菌机制及挖掘次级代谢产物基因资源,有必要解析PRh5菌株的基因组序列信息。【方法】采用高通量测序技术对PRh5菌株进行全基因组测序,然后使用相关软件对测序数据进行基因组组装、基因预测与功能注释、直系同源簇(COG)聚类分析、共线性分析及次级代谢产物合成基因簇预测等。【结果】基因组组装获得290 contigs,整个基因组大小约11.1 Mb,GC含量为71.1%,序列已提交至GenBank数据库,登录号为JABQ00000000。同时,预测得到50个次级代谢产物合成基因簇。【结论】将为Streptomyces sp. PRh5的功能基因组学研究及相关次级代谢产物的生物合成途径与异源表达研究提供基础。     

粘细菌资源挖掘与多相分类研究进展

粘细菌(Myxobacteria)是一类具有复杂多细胞行为、能够广泛捕食各类细菌和真菌并能产生丰富次级代谢产物的药源微生物,具有重要研究和应用价值。然而,由于资源挖掘困难,多相分类研究进展缓慢,严重阻碍了粘细菌的开发利用。本文对粘细菌的特性、分离和纯化方法、目前存在的不足及改进措施进行阐述,并对粘细菌多相分类研究进展及存在的问题进行解析。另外,结合当前技术手段和发展现状,进一步对粘细菌的未来发展趋势进行展望,以期为相关研究提供参考。     

粘细菌生物活性产物及其应用研究进展

粘细菌(myxobacteria)是一类具有多细胞群体行为特征的药源微生物类群。粘细菌能通过次级代谢产生大量结构新颖并具有生物活性的小分子天然产物,还能分泌种类、功能丰富多样的酶类。这些生物活性产物使粘细菌不仅具有重要的研究价值,还有广泛的应用前景。然而,资源挖掘困难、次级代谢产物得率低等制约因素的存在严重阻碍了粘细菌的研究和应用。本文主要对粘细菌的生物学特征、生物活性产物、生物合成调控及在医疗、农业和食品上的应用进行归纳总结,并结合已有成果对粘细菌研究存在的问题提出可能的对策和展望,为今后粘细菌的深入研究和资源开发利用提供参考。     

小单孢菌(Micromonospora rifamycinica)AM105全基因组测序及分析

小单孢菌(Micromonospora rifamycinica)AM105是一种高GC含量的革兰氏阳性放线菌,分离自中国南海红树林沉积物,能够合成利福霉素类抗生素。目前,还没有相关研究报道Micromonospora rifamycinica的全基因组序列,这限制了代谢产物合成途径和比较基因组学等研究。本研究首次通过高通量测序技术对小单孢菌AM105进行全基因组测序,使用Velvet软件进行组装拼接得到388个Contigs,整个基因组大小约6.85 Mb,GC含量为73.1%,序列已提交至美国国立生物技术信息中心(NCBI)的Gen Bank数据库(LRMV01000000)。本研究同时对基因组序列进行了基因预测与功能注释、COG和GO聚类分析及次级代谢产物合成基因簇预测等,相关研究结果将为小单孢菌Micromonospora rifamycinica的功能基因组学研究提供基础数据。     

小单孢菌(Micromonospora wenchangensis DSM 45709)全基因组测序及分析

小单孢菌(Micromonospora wenchangensis)DSM45709是一种高GC含量的革兰氏阳性放线菌,分离自中国海南文昌红树林沉积物。目前,还没有相关研究报道Micromonospora wenchangensis的全基因组序列,这限制了其代谢产物合成途径和比较基因组学的研究。本研究通过高通量测序技术对小单孢菌DSM45709进行全基因组测序,使用Velvet软件进行组装拼接得到150个Contigs,整个基因组大小约7.51 Mb,GC含量为73.04%,序列已提交至给GenBank数据库,登录号为MZMV00000000。本研究同时对基因组序列进行了基因预测与功能注释、COG和GO聚类分析及次级代谢产物合成基因簇预测等,相关研究结果将为小单孢菌Micromonospora wenchangensis的功能基因组学研究提供基础数据。     

粘细菌:一类重要的微生物资源

粘细菌 (Myxobacteria)是革兰氏阴性单细胞杆状细菌 ,具有有独特的生活史 ,在细胞分化发育和生物进化研究中占有重要地位。尤为重要的是粘细菌可产生丰富的次级代谢产物 ,是一类具有重要经济价值的微生物资源。本文简单地介绍了粘细菌生物学特性、分离纯化、系统分类、活性物质的研究 ,以推动粘细菌资源的全面研究、开发和利用。     

粘细菌次生代谢产物中大环类化合物的研究进展

粘细菌可以产生多种次生代谢产物,是继放线菌、芽胞杆菌之后的第3大类次级代谢产物产生菌。本文综述了粘细菌次生代谢产物中大环类化合物的研究进展。首先介绍了粘细菌中分离的主要大环类化合物种类、结构特征及来源菌株;然后分别从抗肿瘤、抗菌、抗病毒等几方面对其生物活性进行概述;最后对粘细菌次生代谢产物中大环类化合物的相关研究工作进行了展望。     

小单孢菌(Micromonospora rosaria)DSM803全基因组测序及分析

小单孢菌(Micromonospora rosaria)DSM 803是一种高GC含量的革兰氏阳性放线菌,分离自美国德克萨斯州土壤,能够合成玫瑰霉素抗生素。目前,还没有相关研究报道Micromonospora rosaria的全基因组序列,这限制了代谢产物合成途径和比较基因组学等研究。本研究首次通过高通量测序技术对小单孢菌DSM803进行全基因组测序,使用Velvet软件进行组装拼接得到310个Contigs,整个基因组大小约7.38 Mbp,GC含量为73.4%,序列已提交至美国国立生物技术信息中心(NCBI)的Gen Bank数据库(LRQV00000000)。比较基因组学及玫瑰霉素合成途径相关基因分析结果显示:小单孢菌DSM 803在碳水化合物转运和代谢及信号转导功能方面要明显强于其它功能;玫瑰霉素生物合成基因簇由20个基因组成并分散于4个Contigs中。本研究首次报道了一株大环内酯类抗生素玫瑰霉素生产菌小单孢菌DSM 803的全基因组序列,分析了基因组基本特征,预测了次级代谢产物合成基因簇,探讨了玫瑰霉素生物合成途径,为后续的进一步代谢调控与合成生物学提供了理论基础。     

植物内生菌及其次级代谢产物的研究进展

植物内生菌经过与寄主植物长期的协同进化,成为植物内生态系统的重要组成部分,在植物的生长发育、营养吸收、胁迫应激以及产生次级代谢产物等生理生化行为方面具有显著的作用。利用植物内生菌及其次级代谢产物,可以促进农作物的生长发育、提高抗逆性,对于农业生产具有重大的研究意义和应用价值。综述了植物内生菌及其次级代谢产物生理功能及在农业生产中应用的研究进展。对植物内生菌及其次级代谢产物未来的研究重点和应用前景做出展望。     

粘细菌So ce cpu-1的鉴定及其抗肿瘤活性研究

目的:从土壤中筛选分离粘细菌并研究其抗肿瘤活性。方法:通过对菌的形态和生理生化特征分析确定其种属。通过MTT法研究粘细菌次级代谢物的抗肿瘤活性。结果:分离得到的粘细菌嗜纤维素属Socecpu-1,次级代谢产物具有很好的抗肿瘤活性。结论:该粘细菌的细胞毒作用呈时间依赖性,是潜在的抗肿瘤药物。     

Analysis of myxobacterial secondary metabolism goes molecular

During the last 20 years myxobacteria have made their way from highly exotic organisms to one of the major sources of microbial secondary metabolites besides actinomycetes and fungi. The pharmaceutical interest in these peculiar prokaryotes lies in their ability to produce a variety of structurally unique compounds and/or metabolites with rare biological activities. This review deals with the recent progress toward a better understanding of the biology, the genetics, the biochemistry and the regulation of secondary metabolite biosynthesis in myxobacteria. These research efforts paved the way to sophisticated in vitro studies and to the heterologous expression of complete biosynthetic pathways in conjunction with their targeted manipulation. The progress made is a prerequisite for using the vast resource of myxobacterial diversity regarding secondary metabolism more efficiently in the future.     

Biology and global distribution of myxobacteria in soils

This review presents an overview of the present status of the biology of the myxobacteria, including the molecular biology of the systems that control and regulate myxobacterial gliding movement and morphogenesis. The present status of myxobacterial taxonomy and phylogeny is described. The evolutionary biology of the myxobacteria is emphasized with respect to their social behavior and the molecular basis of their signal chains. Most important within the metabolic physiology are the biologically active secondary metabolites of myxobacteria and their molecular mechanisms of action. The global distribution of myxobacteria in soils is described on the basis of data given in the literature as well as of comprehensive analyses of 1398 soil samples from 64 countries of all continents. The results are analyzed with respect to the spectrum and number of species depending on ecological and habitat-specific factors. The myxobacterial floras of different climate zones are compared. Included are myxobacterial species adapted to extreme biotopes. The efficiency of different methods used presently for isolation of myxobacteria is compared.     

Myxobacteria isolated in Israel as potential source of new anti-infectives

AIMS: To evaluate the patterns of the production of antimicrobial compounds by Israeli myxobacteria newly isolated from soil samples and barks by a battery of isolation and purification methods. METHODS AND RESULTS: A total of 100 myxobacteria belonging to five of the 12 described genera, were isolated from 48 soil and 45 tree bark samples collected in different areas inside the State of Israel. Four isolation methods based on the peculiar metabolic and cell cycle aspects of myxobacteria, were combined with purification procedures and optimization of cultivation conditions. Ninety-seven strains were fermented and screened for antimicrobial activities. Production of antimicrobial activities was detected in 62 isolates. More than 50% of the collection (54 strains) was able to inhibit Escherichia coli growth. CONCLUSIONS: The results of this study support the idea that myxobacterial strains can be isolated from particular habitats and then cultivated and screened for their capacity to produce secondary metabolites endowed with antibacterial and antifungal activities. Myxovirescin, a typical poliketide myxobacterial antibiotic, has been identified in one Israeli isolate. Althiomycin, a thiazolyl peptide, which inhibits prokaryotic protein synthesis, usually produced by actinomycetes, was detected in three strains selected in this study. SIGNIFICANCE AND IMPACT OF THE STUDY: The results confirm that myxobacteria are prolific producers of a variety of bioactive secondary metabolites including antibacterial and antifungal compounds, being their high frequency of anti-Gram-negative activities particularly appealing for the current anti-infective research. So far their screening has often been hampered because their isolation is time-consuming and are quite difficult to handle and cultivate. In this paper we demonstrate that a proper combination of isolation, purification and cultivation methods allow their pharmaceutical exploitation.     

Myxobacteria: proficient producers of novel natural products with various biological activities--past and future biotechnological aspects with the focus on the genus Sorangium

Myxobacteria are gram-negative bacteria which are most noted for their ability to form fruiting bodies upon starvation. Within the last two decades, they increasingly gained attention as producers of natural products with biological activity. Here, recent and future biotechnological research on certain key myxobacteria and on their ability to produce natural products is reviewed with the focus on the production of myxovirescin, soraphen and epothilone. Aspects of product improvement and yield as well as statistics regarding secondary metabolite formation are discussed. Future research will deal with the exploitation of the biosynthetic potential of the myxobacteria, for example via the isolation of new myxobacterial species with different physiological properties. Additionally, the genetic potential of myxobacteria to form natural products can be exploited by the identification and activation of biosynthetic gene clusters. These can be found frequently within their genomes, which is shown by the analysis of the unfinished genomes of Myxococcus xanthus and Sorangium cellulosum. The current status of the S. cellulosum functional genome project with model strain So ce56 is discussed.     

Leben und Überleben im Boden

Myxobacteria - survivalists in soil Myxobacteria like Myxococccus xanthus are soil-living microorganisms featuring a complex lifestyle, including movement by coordinated swarming on surfaces, predatory feeding on other microorganisms, and the formation of multicellular fruiting bodies when unfavorable environmental conditions are encountered. Bioinformatic analysis of the large myxobacterial genomes has enabled fascinating insights into the molecular basis for the biosynthesis of complex secondary metabolite structures by myxobacteria, and has set the stage for the discovery of novel natural products. Moreover, well-characterized myxobacteria like M. xanthus increasingly play a role as “biochemical factories” for the biotechnological production of bioactive molecules using synthetic biology approaches.     

Biologically active secondary metabolites from myxobacteria

New chemical structures with proven biological activity still are badly needed for a host of applications and are intensively screened for. Suitable compounds may be used as such, or in the form of their derivatives or, equally important, may serve as lead compounds for designing synthetic analogs. One way to new compounds is the exploitation of new producer organisms. During the past 15 years the myxobacteria have been shown in our laboratories to be a rich source of novel secondary metabolites, many of the compounds showing interesting and sometimes unique mechanisms of action. About 50 basic structures and nearly 300 structural variants have been elucidated, and almost all of them turned out to be new compounds. Several myxobacterial substances may have a good chance of an application.     

Discovering the hidden secondary metabolome of Myxococcus xanthus: a study of intraspecific diversity

As a monophyletic group, the myxobacteria are known to produce a broad spectrum of secondary metabolites. However, the degree of metabolic diversity that can be found within a single species remains unexplored. The model species Myxococcus xanthus produces several metabolites also present in other myxobacterial species, but only one compound unique to M. xanthus has been found to date. Here, we compare the metabolite profiles of 98 M. xanthus strains that originate from 78 locations worldwide and include 20 centimeter-scale isolates from one location. This screen reveals a strikingly high level of intraspecific diversity in the M. xanthus secondary metabolome. The identification of 37 nonubiquitous candidate compounds greatly exceeds the small number of secondary metabolites previously known to derive from this species. These results suggest that M. xanthus may be a promising source of future natural products and that thorough intraspecific screens of other species could reveal many new compounds of interest.