肇庆星湖湿地可培养放线菌多样性

Diversity of cultivable actinobacteria in Xinghu wetland sediments

摘要:

摘要:【目的】探究星湖湿地可培养放线菌物种多样性，筛选潜在药源活性代谢产物产生菌，为后续菌种资源开发奠定基础。【方法】采用5种选择性分离培养基分离星湖湿地底泥中的放线菌，通过16S rRNA基因同源性分析代表性菌株的物种多样性;以3株病原细菌为指示菌检测分离菌株的抑菌活性;PCR扩增代表菌株的聚酮合酶(PKS I、PKS II)基因、非核糖体多肽合成酶(NRPS)基因、安莎类化合物(AHBA)基因及3-羟基-3-甲基戊二酰辅酶A还原酶(HMGA)基因。【结果】分离到135株放线菌菌株，被鉴定为放线菌纲的7 个目、10个科、13个属，优势类群为链霉菌、小单孢菌及诺卡氏菌。83株检测菌中，24.09%抗金黄色葡萄球菌(Staphylococcus aureus)，4.8%抗大肠杆菌(Escherichia coli);24株高活性菌株中PKS I阳性率16.7%，PKS II阳性率62.5%，NRPS阳性率16.7%，AHBA阳性率12.5%，HMGA阳性率29.2%。活性复筛及HPLC结果显示，菌株XD007、XD114和XD128显著抑制3株病原指示菌，且能产生大量次级代谢产物。【结论】星湖湿地底泥中放线菌资源丰富，筛选到的活性菌株可用于后续药源活性次级代谢产物的分离。

Abstract:

Abstract:［Objective］To study the diversity of cultivable actinobacteria in Xinghu wetland and screen actinobacteria with a pharmaceutical potential for producing biologically active secondary metabolites.［Methods］We studied the diversity of actinobacteria isolated from Xinghu wetland by using different selective isolation media and methods. The high bioactive actinobacteria were identi ed and further investigated for the presence of polyketide synthases (PKS-I，PKS-II)，nonribosomal peptide synthetases (NRPS)，3-amino-5-hydroxybenzoic acid synthases (AHBA) and 3-hydroxy-3-methylglutaryl Coenzyme A (HMG CoA) sequences by speci c ampli cation．［Results］More than 300 actinobacteria were isolated，and 135 isolates were selected on the basis of their morphologies on different media and were further characterized by 16S rRNA gene sequencing． The isolates belonged to 7 orders，10 families，13 genera，Streptomyces was the most frequently isolated genus，followed by the genera Micromonospora and Nocardia． Twenty-four isolates showed high activity against Staphylococcus aureus and Escherichia coli，but there no strain displaying antagonistic activity against Salmonella sp．High frequencies of positive PCR amplication were obtained for PKS-I (16.7%，4 /24)，PKS-II (62.5%，15/24)，NＲPS (16.7%，4/24)，HMG CoA (29.2%，7/24) and AHBA (12.5%，3/24) biosynthetic systems． High Performance Liquid Chromatography showed that strain XD7，XD114，XD128 produce lots of secondary metabolites.［Conclusion］This study indicated that actinobacteria isolated from Xinghu wetland are abundant and have potentially benecial and diverse bioactivities which should be pursued for their biotechnical promise.