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

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

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。

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 wereobserved by scanning electron microscopy. 16 S rDNA sequencing, Blast and phylogenetic tree analysis were used to identifythe 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 membranestructure of Candida albicans, and Trichophyton rubrum mycelium broken into pieces. 16 S rDNA PCR, Blast and phylogenetictree showed that WA2-4 and WA2-5 belonged to Streptomyces and Gordonella respectively, and homologous to the 16 S rDNAsequences of their respective strains were 93.5% and 92.3% respectively. It＇s concluded the two strains were likely to be newstrains, for all lower than 98.2%. Conclusion WA2-4 and WA2-5 from Cockroach intestines have antifungal activity.