武陵山放线菌多样性

Diversity of actinomycetes in Wuling Mountain

摘要:

【目的】为了探究武陵山放线菌多样性，以便从新放线菌菌株中发现新的潜在药物先导化合物。【方法】从武陵山采集280份土样，采用纯培养的方法，用4种培养基分离到1134株放线菌。选择其中30株代表菌进行了初步分类鉴定；以3株细菌和7株农作物致病真菌作为指示菌，检测其抑菌活性；利用特异性引物扩增的方法，检测是否具有聚酮合酶(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。【结果】分离到的武陵山放线菌中，链霉菌占70%以上，还有小单孢菌等8个科13个属，其中有5个菌株是潜在的新种。选取的30株实验菌对细菌、真菌有不同程度的抗菌活性；其中含有4类化合物合成基因的菌株占23%~60%。【结论】武陵山原始森林土壤中，放线菌多样性很丰富，且存在很多未开发的稀有类群。有抑菌活性的菌株，可用于进一步的药物开发利用。

Abstract:

[Objective] To isolate new actinomycetes for discovering compounds of pharmaceutical importance. [Methods] We collected 280 soil samples from virgin forest in Wuling Mountain. In total 1134 actinomycetes were isolated by culture-dependent method. Of them 30 strains were selected and then characterized by phylogenetic analysis based on sequences of 16S rRNA gene. Antimicrobial activities were determined by agar well diffusion method, and genes of typeⅠandⅡpolyketide synthases (PKSⅠ, PKSⅡ), nonribosomal peptide synthase (NRPS) and polyene cytochrome P450 hydroxylase (CYP) were screened by PCR. [Results] Thirty strains belonged to 8 families, 13 genera: Streptomyces (>70%), Micromonospora, Dactylosporangium, Catellatospora, Sphaerisporangium, Streptosporangium, Actinomadura, Nonomuraea, Nocardia, Rhodococcus, Arthrobacter, Microbacterium, and Pseudonocardia. There are 5 novel species candidates. Thirty strains showed different antimicrobial activities against one to three bacteria and pathogenic fungi. [Conclusion] Abundant diversity of actinomycetes existed in the virgin forest of Wuling Mountain which has many new taxa, and Streptomyces is the predominant population. The strains showed high antimicrobial activities and can be further researched for exploiting new compounds of pharmaceutical.