摘要目的 评价限制性片段长度多态性(Restriction fragment length polymorphism,RFLP)方法检测α和a交配型位点内GEF1α/a基因片段在鉴定新生和格特隐球菌种、变种、基因型和交配型中的作用.方法 筛选交配型位点内的GEF1α/a基因进行PCR-RFLP分析.根据各基因型和交配型参考株的GEF1α/a基因保守序列设计引物,扩增受试新生和格特隐球菌GEF1α/a基因部分片段.利用DNAMAN和Vector NTI软件进行序列比对、限制性图谱分析、限制性内切酶的筛选和模拟电泳.选择EcoTl4 Ⅰ和Hap Ⅱ限制性内切酶分别对125株新生和格特隐球菌的GEF1α/a基因扩增片段进行RFLP分型.结果 所有受试的82株新生隐球菌和43株格特隐球菌均扩增出1 300 bp大小片段,而罗伦隐球菌、白念珠菌、热带念珠菌、近平滑念珠菌、克柔念珠菌、光滑念珠菌、阿萨希毛孢子菌、烟曲霉和黄曲霉参考株均扩增阴性.RFLP分型准确鉴定所有125株新生和格特隐球菌的种、变种、基因型和交配型.结论 针对GEF1α/a基因片段的PCR-RFLP方法特异性高、稳定性好,适用于新生和格特隐球菌种、变种、基因型和交配型的同步和快速鉴定以及进一步的分子流行病学分析.

abstractsObjective To evaluate the role of Restriction fragment length polymorphism (RFLP) analysis in detection of the fragment of GEF1α/a gene which are both located at ct and a mating type loci in identification of species, varieties, genotypes and mating types of Cryptococcus neoformans species complex(Cryptococcus neoformans and Cryptococcus gattii). Methods The GEF1α/a gene was selected from 20 genes which both located at α and a mating type loci for RFLP analysis, according to the requirements of sequence similarities and primer design in PCR-RFLP analysis. Primer pair was designed from the conserved regions of GEF1α/a genes of distinct genotypes and mating types of reference strains to amplify a fragment of GEF1α/a gene from Cryptococcus neoformans and Cryptococcns gattii strains tested. Sequence alignment,restriction maps analysis, endonucleases selection and electrophoresis stimulation were conducted by using DNAMAN and Vector NTI software. EeoT14 Ⅰ and Hap Ⅱ endonucleases were selected for RFLP analysis of the GEF1α/a fragments amplified from 125 isolates of Cryptococcns neoformans and Cryptococcus gattii. Results An approximate 1 300 bp fragment was amplified from total 82 Cryptococcus neoformans and 43 Cryptoceccus gattii isolates. However, negative PCR results were found in the reference strains of Cryptococcus laurentii, Candida albicans, Candida tropicalis, Candida parapsilosis, Candida krnsei,Candida glabrata, Trichosporon asahii, Aspergillus fumigatns and Aspergillus flavus. RFLP analysis successfully identified the species, varieties, genotypes and mating types of total 125 isolates of Cryptococcus neoformans and Cryptococcns gattii tested in this study. Condusion PCR-RFLP analysis of the GEF1α/a fragment has the potential value in identification of species, varieties, genotypes and mating types of Cryptococeus neoformans species complex simultaneously and rapidly, and may be a useful tool in molecular epidemiological analysis.