青藏高原阿里地区沙漠放线菌资源勘探及抗菌活性研究

打开文本图片集

中图分类号：R9 文献标志码：A

Abstract Objective To investigate the diversity of actinomycetes and antimicrobial potential in desert soilsof the Ngariregion，Xizang，usingclassical culture-dependent techniques.The findings laidthe foundation for exploring actinomycetes resources in high-altitude desert ecosystems and ofered strains forthe discoveryof novel antibiotics.MethodsThirty-eight desert soil samples were collcted from the Xiangquan River and Shiquan River basins in Ngari.Actinomycetes were isolated bythe standard soil dilutionplating techniqueand purified by the streak plate method.Preliminary taxonomic identification and novelty assssment were performed through 16S rRNA gene sequence analysis and phylogenetic tree construction. Representative strains were screened for secondary metabolite biosynthetic geneclusters （PKS I，PKS II，and NRPS）using PCR.Some strains with biosynthetic gene clusters were selected for antimicrobial assays.ResultsAtotal of648 actinomycetes strains were isolated from 38 samples using eight selective isolationmedia，representing9orders，16families，and36genera，including13 potentialnovel species. Among 185 representative strains，174 were detected as positive strains for secondary metabolite biosynthetic gene clusters，with46 strains harboring allthree typesofbiosynthetic gene clusters.Antimicrobial assay for52 strains resulted in24 positive strains，including14 Streptomycesand10areactinomycetes.NotablyStreptomyces sp.PX32- 12 exhibited broad-spectrum antimicrobial activities against multiple pathogenic bacteria， while Saccharothrix sp. RX49-8 showed significant antagonistic activity against Mycobacterium smegmatis. ConclusionThe desert soils of the Ngari harbor abundantactinomycetes，including rareactinomycetes，novel species，and high-qualitymedicinal strains with the potential for further studies.

Key WordsNgari region; Desert; Actinomycetes; Novel species; Antimicrobial activity

以链霉菌为代表的放线菌是自然界中最重要的抗生素来源之一[I。（剩余15880字）