| Objectives : To study the distribution characteristics of aerobic actinobacteria in different types of soils in Guizhou region; to evaluate the anti-microbial activity and stability degree of some strains against clinical common pathogenic bacteria and fungi; and to determine the taxonomic status of strain IFM 10348 T by using the polyphasic taxonomic approach. Methods 1. Farming land, wetland and forest soil samples were collected from 9 regions of Guizhou including Zunyi, Anshun,Guiyang, Tongren, Bijie, Qiannan, Liupanshui, Qiandongnan and Qianxinan for isolation and purification of aerobic actinomycetes.DNA was extracted by Enzyme method, the phylogenetic tree was established using neighbor-joining method. 2. The bacterial and fungal susceptibility testing with Kirby-Bauey method was carried out, and the analyses of different temperature, illumination, p H conditions for the broth stability were tested.3. The taxonomic status of strain IFM 10348 T was determined by using a polyphasic taxonomic approach. Results 1. One hundred and seventy three aerobic actinobacterial strains in this area were isolated and identified,and their 16 S r RNA gene sequences were amplified for construction of phylogenetic tree. The result shows that 165 of the above strains belong to Streptomyces,5 of them belong to Kitasatospora,2 strains are Nocardioides, 1 strain isolated from the Zunyi agricultural land is suggested as the possible novel species.2.The metabolic substances of some strains showed ideal anti-microbial activity against Staphylococcus aureus, Escherichia coli, Salmnella paratyphi B, Candida albicans and Cryptococcus neoformans. The change of temperature, illumination can not influent the broth’s stability and the optimum p H is in the range of 5-7.3. The results obtained from this study suggested that strain IFM 10348 T represents a novel species of the genus Gordonia. Conclusions 1. According to the above analysis,the majority isolates in Guizhou area are Streptomyces,which can be isolated from every location in this study but show obvious taxonomic diversity and geographical differences under species level. 2. The result of this study provides not only strain resource for novel antibiotics, enzymes and other biologically active substances, but also the experimental and theoretical data for the separation and purification of the relevant active substance in the future.3. The name Gordonia iterum sp. nov. is proposed for strain IFM 10348 T according our study here. |
