Diversity and bioactivity of cultured actinomycetes in Sichuan and Yunnan area

Abstract:

Abstract: [Objective] In order to discover new leader compounds, the diversity and some bioactivities of cultured actinomycetes from Sichuan and Yunnan were studied. [Methods] In total 250 soil samples were collected from forest of Huangjin, Emei and Qingcheng Mountains, Jiuzhaigou in Sichuan, and Xishuangbanna in Yunnan. Actinomycetes in these samples were isolated and identified. Bioactivities of isolated strains were determined. [Results] In total 2676 strains of actinomycetes were isolated from these samples. The 16S rRNA gene sequences of 98 selected strains were determined, and the phylogenetic analysis was carried out. 13, 5, 9 and 20 genera were identified from Forest of Huangjin, Emei and Qingcheng Mountains (one sample area), Jiuzhaigou, and Xishuangbanna respectively. The diversity of Xishuangbanna was the richest. That of Emei and Qingcheng Mountains was monotone, and only five genera were isolated. Antimicrobial activities of 169 selected strains against 11 bacteria and fungi were tested using agar well diffusion method, and genes of type I and II polyketide synthases (PKS I, PKS II), non-ribosomal peptide synthase (NRPS) and polygene cytochrome P450 hydroxylase (CYP) were detected by PCR. High rate of antimicrobial activity and the synthesis genes of four antibiotic existed in these actinomyctes. [Conclusion] In sample-collecting areas, the poorer human beings disturbance, the richer the diversity of actinomycetes. For isolation of actinomycetes, author advocate using of "extreme" conditions, although it may got small number of actinomycetes, but the proportion of unknown actinomycetes was greater. Gram-negative bacteria and fungi could be inhibited by adding inhibitors in media.