| A total of 168 strains of actinomycetes, of which 23, or 13.7%, displaying antitumor activity, was isolated from near-shore marine samples collected at WenChang mangrove, DanZhou harbor and YanPu harbor, three isolation methods were employed, which are SDS pretreatment, phenol pretreatment, Heating pretreatment and potassium dichronate selection culture, and various media were used . One hundred and sixty-four strains of these actinomycetes were isolated from marine mangrove, accordingly, it was suggested that mangrove area has great potential for acquiring actinomycete. It was showed that SDS pretreatment and potassium dichromate selection culture both eliminated or severely curtailed the growth of contaminating microorganisms, thereby facilitating the isolation of actinomycetes. However phenol pretreatment greatly inhibit the growth of actinomycete meanwhile. Compared with SDS pretreatment, potassium dichromate selection culture is more feasible for extensive isolation of actinomycete. Medium of YE showed best results in both the total number of actinomycetes and the number of active strains against tumor cell B16.The genotypic diversity of 30 strains of marine actinomycetes possessing strong antitumor activity (ID50>200), 15 of which were isolated by my collaborate was analysed, by 16S ARDRA, which showed 17 RFLP types, and indicated relatively rich genotypic diversity among these actinomycetes. It was observed that genotypic difference was among stains from distinct sampling sites and strains that were picked out from some plates with similar culture characteristics. As to the same sampling location, different pretreatment and culture media showed similar selectivity on theactive strains.16S rDNA sequence analysis of three strains of 050642, 060386 and 060524 whose ID50 is above 1200 indicated they also belong to Streptomyces genus and strain 050642 is suspected to be a novel Streptomyces. spp with the highest similarity to Streptomyces colicolor, at 95%. |
PDF Full Text Request