[Objective] This study was aimed to isolate and identify the actinobacteria with antitumor activity isolated from a soil sample collected from the Ba-yi town,Nyingchi,Tibet,China.[Methods] Actinobacteria were isolated and purified by agar plate dilution method planting in Gause 1 and glucose/asparagines agar media.To test the biological active effects in vitro of the actinobacteria fermentations and its' crude extracts,we used MTT assay with 5 human tumor cell lines to monitor the antitumor activity,paper-dish method with 7 indicative microorganism strains (bacteria and fungi),and 4 antibiotics to detect the antimicrobial activity and resistance.The polyphasic taxonomies of the antitumor active strains were studied according to morphological,cultural,physiological,biochemical characteristics and 16S rRNA gene sequence analysis.[Results] We isolated 29 actinobacteria strains of which 6 strains with good antitumor activities were obtained (20.7％).All of the crude extracts of the 6 strains had remarkable inhibiting effects against the 5 human tumor cell lines and different degrees of antimicrobial activity against the indicator microorganisms.The crude sample of 4 of them had the inhibition rate of more than 80％ on Hela cell line.Only one active strain had good tolerance for 4 kinds of antibiotics.Taxonomic studies showed that all of the 6 antitumor active strains were related to Streptomyces.These 6 strains may be variants of the three known Streptomyces species (Streptomyces galbus,Streptomyces mirabilis,Streptomyces olivochromogenes) respectively.[Conclusion] The actinobacteria in Ba-yi town of Nyingchi are rich in Streptomyces with antitumor activities and may be a potential microbial resource for antitumor drugs.
NETL
NSTL
万方数据
维普
