马拉色菌属种内基因多态性机制的分析

Analysis of intra-specific genetic diversity of Malassezia

目的分析RAPD法对马拉色菌属分型的可靠性,并探讨马拉色菌属种内基因多态性的机制。方法分别用RAPD法和传统的生化法对74株马拉色菌临床株进行分型鉴定,比较两者结果的异同。扩增7株糠秕马拉色菌ITS1区,并进行SSCP分析。结果大部分马拉色菌的RAPD分型结果与生化结果是符合的,但也有9株马拉色菌被归入别的种。同时即便被归入同一类的菌株也存在多态性的RAPD带型。对糠秕马拉色菌的ITS1区进行SSCP分析可看到明显的单链构象差异,而且其差异程度在RAPD分型中得到了印证。结论由此推断种内基因多态性会干扰马拉色菌的分子分型,而ITS1的序列是种内基因多态性的敏感指标。

Objective To evaluate the reliability of classification of Malassezia species by RAPD and to investigate the mechanism of intra-species genetic diversity of Malassezia.Methods Seventy-four Malassezia clinical isolates were identified and classified by both RAPD and traditional biochemical techniques.The difference of two classification methods was evaluated.ITS1 region of 7 Malassezia furfur isolates was amplified and further investigated by SSCP.Results In most isolates,the result of RAPD classification is in accordance with that by biochemical technique.However,there are still 9 isolates classified into different species by two methods.Besides,polymorphic RAPD patterns can be observed in some isolates of the same specie.trur by SSCP revealed obvious variation of Single-Strand Conformation.Moreover,such variation was in accordance with RAPD result.Conclusion We suggest that intra-species genetic diversity may interfere with molecular biological classification of Malassezia,and that sequence of ITS1 is the sensitive index for intra-species genetic diversity.