大香格里拉土壤放线菌组成分析及生物活性测定

Analysis of actinomycetes isolated from Grand Shangri-La soil

摘要:

【目的】探究大香格里拉地区的土壤放线菌组成及其抑菌和酶活性，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】从大香格里拉地区不同海拔高度采集220份土样，用4种培养基，分别进行了常温放线菌和低温放线菌的分离。从常温放线菌中选择25株代表菌株进行了初步分类鉴定。采用琼脂扩散法，检测了其对4株细菌和7株农作物致病真菌的抑菌活性；利用特异性引物扩增法，筛选了其聚酮合酶(PKSⅠ、PKSⅡ)基因、非核糖体多肽合成酶(NRPS)基因和多烯类化合物合成酶(CYP)基因。同时，检测了低温菌的多种酶活性。【结果】25株常温代表菌的系统发育分析显示它们分属于放线菌目的6个亚目、12个科、15个属。其中14株菌的NRPS及11株的CYP基因筛选呈阳性。低温条件下分离到的111株放线菌，88%属于耐冷菌，12%是嗜冷菌，它们中的大部分能利用明胶、纤维素，甲壳素等。【结论】研究结果显示，大香格里拉森林土壤蕴涵着种类和活性丰富的放线菌，为放线菌资源的开发利用和保护提供了新依据。

Abstract:

[Objective] To obtain new pharmaceuticals and enzymes with high activity, we studied the composition as well as antimicrobial and enzyme activities of actinomycetes in Grand Shangri-La. [Methods] Using 4 media, we isolated mesophilic and psychrophilic actinomycetes from 220 soil samples collected from areas with different altitudes in Grand Shangri-La. Twenty-five representative isolates were phylogenetically analyzed based on their 16S rRNA gene sequences. Antimicrobial activities against four bacteria and seven fungi were tested using agar well diffusion method. Genes encoding typeⅠandⅡ polyketide synthases (PKSⅠ, PKSⅡ), nonribosomal peptide synthase (NRPS) and polyene cytochrome P450 hydroxylase (CYP) were screened by PCR. Furthermore, several enzyme activities of psychrophilic actinomycetes were examined. [Results] The 25 representative strains belonged to 6 suborders, 12 families and 15 genera of the order Actinomycetals. For NRPS and CYP genes screening, positive strains were 14 and 11, respectively. Among the 111 actinomycetes isolated under low-temperature conditions, 88% were psychrotroph strains, 12% were psychrophilic actinomycetes, and most of them utilized gelatin, cellulose and chitin. [Conclusion] Actinomycetes diversity isrich in Grand Shangri-la, and has the potential for conservation and utilization of actinomycetes resources.