星海链霉菌抑菌活性物质的分离纯化

星海链霉菌(Streptomyces xinghaiensis)是从大连星海湾海泥样品中分离的海洋链霉菌新种,其发酵液具有广谱抗菌活性。研究该菌株的发酵液对临床分离的耐药菌的抑制活性,发现星海链霉菌发酵液对鲍曼不动杆菌和耐甲氧西林金黄色葡萄球菌菌株具有抑制活性。采用SPE、大孔吸附树脂HP-20、葡聚糖凝胶Sephadex LH-20、HPLC、TLC等对抗耐甲氧西林金黄色葡萄球菌的物质进行了活性追踪,发现活性物质为弱碱性水溶性成分,无特征紫外吸收,可被茚三酮显色,推断活性物质可能为氨基糖苷类化合物。对星海链霉菌基因组序列进行初步分析,发现一个与核糖霉素生物合成基因簇相似性较高的基因簇,但TLC分析结果表明,活性化合物与核糖霉素不同。

Purification of the antimicrobial compounds from Streptomyces xinghaiensis

Streptomyces xinghaiensis is a novel Streptomyces species isolated from marine sediment sample collected in Xinghai Bay, Dalian, China, and wide spectrum of antimicrobial activities of its fermentation broth has been observed. In this study, the antibacterial activities of the fermentation broth of S. xinghaiensis against drug-resistant clinical isolates were investigated, and inhibitory activities against Acinetobacter baumannii and Staphylococcus aureus (MRSA) strains were revealed. Purification of the active compound (s) against methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates was performed and the properties of the active compounds were studied. Active fractions were obtained after treatments of the broth with macroporous adsorptive resin HP-20 and Sephadex LH-20. The active components were weak alkaloid compounds with no specific UV adsorption, and ninhydrin coloration further supported the hypothesis that the active compounds likely belong to aminoglycoside antibiotics. The draft genomic sequence of S. xinghaiensis was searched and a ribostamycin-related gene cluster was identified. However, Thin Layer Chromatography (TLC) analysis indicated that the major components of the active compounds are different from ribostamycin.