两株蜚蠊肠道内生放线菌抗真菌活性初步研究和分类鉴定

目的检测蜚蠊肠道内生放线菌WA2-4和WA2-5的抗真菌活性,并对菌株进行初步分类学鉴定。方法采用牛津杯法测定菌株WA2-4和WA2-5发酵液对白色念珠菌和红色毛癣菌等真菌生长的影响,扫描电子显微镜观察菌株发酵液对受试真菌形态的影响,利用16S rDNA测序、Blast比对和构建系统发育树等方法,结合菌株形态学特征对菌株WA2-4和WA2-5进行初步分类学鉴定。结果菌株WA2-4和WA2-5发酵液对白色念珠菌和红色毛癣菌的生长均有抑制作用;扫描电子显微镜结果显示菌株WA2-4和WA2-5发酵液破坏了白色念珠菌的细胞膜结构,使红色毛癣菌的菌丝断裂成碎片;初步分类学鉴定结果显示,菌株WA2-4和WA2-5分别为链霉菌属和戈登氏菌属,与其各自亲缘菌株的16S rDNA序列同源相似性分别为93.5%和92.3%,均低于98.2%,因此推断该两株菌株很有可能是新菌种。结论蜚蠊肠道WA2-4和WA2-5放线菌具有抗真菌活性。

Preliminary study on antifungal activity and classification of two endophytic actinomycetes from Cockroaches intestines

Objective To detect the antifungal activity of endophytic actinomycetes WA2-4 and WA2-5 from Cockroach intestines,and we identify the preliminary taxonomy.Methods The antifungal activity on Candida albicans and Trichophyton rubrum of WA2-4 and WA2-5 were determined by Oxford cup method,and the effects on the morphology of tested fungi were observed by scanning electron microscopy.16S rDNA sequencing,Blast and phylogenetic tree analysis were used to identify the strains WA2-4 and WA2-5.Results The fermentations of WA2-4 and WA2-5 inhibited the growth of Candida albicans and Trichophyton rubrum.Scanning electron microscopy showed the strains WA2-4 and WA2-5 destroyed the cell membrane structure of Candida albicans,and Trichophyton rubrum mycelium broken into pieces.16S rDNA PCR,Blast and phylogenetic tree showed that WA2-4 and WA2-5 belonged to Streptomyces and Gordonetla respectively,and homologous to the 16S rDNA sequences of their respective strains were 93.5％ and 92.3％ respectively.It's concluded the two strains were likely to be new strains,for all lower than 98.2％.Conclusion WA2-4 and WA2-5 from Cockroach intestines have antifungal activity.