桐花树内生和根际细菌多样性及抗血栓活性研究

红树植物内生菌在红树共生体的物质循环、能量传递和健康维护等方面起着重要作用。为探究红树植物内生菌的多样性,进一步揭示内生菌在红树共生体的功能多样性提供菌种资源,该研究选择6种分离培养基和采用传统稀释涂布法对从广西北海滩涂上采集的桐花树组织和根际土壤样品进行分离,对获得的可培养细菌进行多样性分析,并通过体外溶栓实验筛选出具有抗血栓活性的菌株。结果表明:(1)基于16S rRNA基因序列系统进化分析,从桐花树组织和根际土壤中共获得125株细菌;分布于变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和厚壁菌门(Firmicutes) 3个门27个科39个属74个种中,芽孢杆菌属为优势菌属,菌株数量占13.5%。(2)抗血栓活性实验表明,初筛获得18株具有抗血栓活性细菌,总阳性率为24.32%;将初筛有活性的菌株进行复筛和重复验证实验,进一步验证其活性,结果复筛出3株细菌B1850、B1989和B2632具有很强抗血栓活性。综上所述,广西北海滩涂上红树植物桐花树中存在丰富的可培养细菌资源,具有从中挖掘新的纤溶酶和开发溶血栓药物的潜力。

Diversity and anti-thrombotic activity of endophytic and rhizospheric bacteria isolated from Aegiceras corniculatum

Mangrove endophytes play an important role in the material cycle, energy transfer and health maintenance of mangrove plants. In order to enrich microbiological resources for further revealing the functional diversity of the endophytes microorganism in mangrove plants, in this study, we investigated the distribution and diversity of endophytic and rhizospheric bacteria of Aegiceras corniculatum collected from Beihai City, and studied the anti-thrombotic activities of those strains. The endophytic and rhizospheric bacteria were isolated from A. corniculatum by using six different isolation media. The anti-thrombotic activities of all species were screened out by thrombolysis experiment in vitro. The results were as follows:(1)Based on the phylogenetic analysis of 16S rRNA gene sequence, a total of 125 strains were obtained from the tissue and rhizosphere soil of A. corniculatum. They were classified into 74 species, 39 genera, 27 families and 3 phylas of Proteobacteria, Actinobacteria and Firmicutes. Bacillus sp. was the dominant genus, and the total rate was 13.5%.(2)The results of anti-thrombotic activity test showed that 18 strains with anti-thrombotic activity were screened out, and the total positive rate reached to 24.32%. The activity of the strains was further verified by the re-screening and re-verification test. The strains of B1850, B1989 and B2632 with strong anti-thrombotic activity were obtained. To sum up, there are abundant culturable bacterial resources in Aegiceras corniculatum in Beihai of Guangxi, which could be a potential source for the discovery of new plasminogen and thrombolytic drugs.