西藏低温放线菌的多样性及其生物活性

Biological activity and diversity of psychrophilic actinomycetes in Tibet

【目的】研究西藏低温环境下放线菌的组成及其抑菌效果和酶活性,为放线菌新药物先导化合物和高活性酶的筛选提供资源。【方法】从西藏低温地区采集16份土样,用平板稀释法分离放线菌,经形态学和培养特征初步鉴定后得到有代表性的低温放线菌,对这些代表性菌株的16S rRNA基因序列进行系统发育分析,对其进行鉴定;采用菌丝生长速率法测定代表性低温放线菌菌株发酵液对11种农作物真菌的抑菌活性,并对其纤维素酶、蛋白酶、淀粉酶等活性进行测定。【结果】从16份土样中共分离到22株有代表性的低温放线菌,其在10~25℃均能生长。16S rRNA基因序列分析表明,这22株菌分布于放线菌门放线菌纲2个亚目3个科的3个属,即链霉菌亚目(Streptomycineae)链霉菌科(Streptomycetaceae)链霉菌属(Streptomyces)、假诺卡氏亚目(Pseudonocardineae)束丝放线菌科(Actinosynnemataceae)伦茨氏菌属(Lentzea)和假诺卡氏亚目(Pseudonocardineae)假诺卡氏菌科(Pseudonocardiaceae)拟无支酸菌属(Amycolatopsis),其中以链霉菌属最多,占分离菌的91%。在分离的22株代表性低温放线菌菌株中,27.3%的菌株有抑菌活性;40.9%的菌株具有纤维素酶活性,22.7%的菌株具有淀粉酶活性,18.2%的菌株具有蛋白酶活性。【结论】西藏低温生境中蕴藏着丰富的低温放线菌资源,其中一些菌株具有拮抗活性和酶活性。

[Objective] This study investigated the composition, antibacterial effects and enzyme activi- ties of psychrotophilic actinomycetes in Tibet to provide resources for lead compounds of new drugs and enzymes with high activities. [Methodl A total of 16 soil samples were collected from low temperature re- gion in Tibet and the actinomycetes were isolated by plate dilution method. Representative psychrotophilic actinomycetes were identified by morphological and cultural characteristics, and were analyzed and identi- fied by 16S rRNA gene sequence. Antifungal activities of the representative strains were measured by growth rate method,and cellulase, protease and amylase activities were determined. [Resultl A total of 22 strains of psychrotophilic actinomycetes were isolated from 16 soil samples. They can grow at the tempera- ture of 10--25 ~C. The 16S rRNA gene sequence analysis showed that the 22 isolates belonged to 3 subfam- ilies of three genera including Streptomyces of Streptomycineae and Streptomycetaceae,Lentzea of Pseud- onocardineae and Actinosynnemataceae,and Amycolatopsis of Pseudonocardineae and Pseudonocardiaceae. Most of which Streptomyces,accounting for 91~ of the isolated psychrophilic actinomycetes. Among the 22 isolates,40. 9% had cellulase activity, 22. 7% had amylase activity, 18. 2% had protease activity, and 27.3% had antifungal activity. [Conclusion] Tibet low-temperature habitat had rich low-temperature acti- nomycetes resources, and some of them had antagonistic and enzyme activities.