南太湖沉积物中可培养放线菌的分离、鉴定及其抑菌活性

Isolation,identification,and antimicrobial activity ofculturable Actinomycetes from the sediment of South Taihu Lake

为研究南太湖沉积物中可培养放线菌,并筛选具高抗水产病原菌的活性菌株,通过分离培养基分离纯化放线菌,通过形态学特征观察、16S rRNA基因序列比对和系统发育分析对南太湖沉积物中可培养放线菌进行分类鉴定,采用琼脂块法和牛津杯法测试分离菌株及其2种发酵液对3种水产病原菌荧光假单胞菌(Pseudomonas fluorescens)、嗜水气单胞菌(Aeromonas hydrophila)、维氏气单胞菌(Aeromonas veronii)的拮抗作用。从南太湖沉积物中共分离得到160株放线菌菌株,隶属于6个目、9个科和12个属,除优势菌群链霉菌(Streptomyces)外,还分离到小单孢菌属(Micromonospora)、诺卡氏菌属(Nocardia)、北里孢菌属(Kitasatospora)和壤霉菌属(Agromyces)等,通过优良拮抗放线菌初筛,26株放线菌对至少一种水产病原菌具有抑菌活性,通过对初筛有抑菌活性的菌株进行优良拮抗放线菌复筛,9株放线菌对水产病原菌仍具有抑制活性,其中菌株Spr-T-4-14发酵液对3种病原菌具抑菌活性,为后续进一步研究其活性次级代谢产物提供了依据。

In order to study the culturable actinomycetes in the sediments of South Taihu Lake and screen the active strains with high actimicrobial to aquatic pathogens,the culturable actinomycetes were classified and identified from sediments of South Taihu Lake by morphological characteristics,16S rRNA gene sequence alignment and phylogenetic analysis.The antagonistic effects of the isolated strains and their two fermentation fluids against Pseudomonas fluorescens,Aeromonas hydrophila and Aeromonas veronii in aquatic pathogens were tested by AGAR block method and Oxford Cup method.The results showed that a total of 160 representative strains,belonging to 6 orders,9 families and 12 genera,were isolated from the sediment samples of South Lake Taihu,and in addition to the dominant group of Streptomyces,the rare genera of Micromonospora,Nocardia,Kitasatospora and Agromyces were also isolated.Through the preliminary screening of good antagonistic actinomycetes,26 strains of actinomycetes had inhibitory activity against at least one aquatic pathogen,and through the re-screening of good antagonistic actinomycetes for the strains with inhibitory activity in the preliminary screening,9 strains of actinomycetes still had inhibitory activity against aquatic pathogens,among which the fermentation broth of strain Spr-T-4-14 had inhibitory activity against 3 pathogens,which provided a basis for further research on their active secondary metabolites.