摘要
目的:
以一系列同一亲本来源对氟康唑敏感性不同的白念珠菌为对象,研究其菌丝相与酵母相ERG11基因序列及分泌性酸性蛋白酶活性之间的差异,从而为白念珠菌病原真菌学和临床检验学中,究竟是选择白念珠菌的菌丝相还是酵母相为研究对象提供理论依据。
方法:
对12株分离自同一HIV阳性者的白念珠菌分别进行菌丝相与酵母相培养后,抽提基因组DNA,PCR扩增ERG11基因(包括部分上游和下游非编码区),PCR产物用Acc Ⅰ和Mun Ⅰ消化,消化产物进行琼脂糖凝胶电泳(PCR-RFLP);选择其中5株白念珠菌,用下游引物对部分ERG11基因进行测序,比较两相细胞ERG11基因序列差异;用牛血清白蛋白培养基测定8株白念珠菌菌丝相与酵母相分泌性酸性蛋白酶的活性。
结果:
1.CA-7、CA-14,CA-16和CA-17的菌丝相与酵母相ERG11基因酶切图谱存在差异;
2.CA-7菌丝相与酵母相ERG11基因第1547位点、1587位点和1617位点的碱基存在差异;
Objective:To provide evidence for selecting the suitable form of Candiada albicans in medical mycology, the differences between the hyphal form and the yeast form of C. albicans on ERGll gene sequence and on the activity of secreted aspartyl proteinase were compared in this study.Materials and Methods:Twelve isolates of C. albicans from a single HIV-seropositive patient (CA-1, CA-2, CA-4, CA-6, CA-7, CA-9, CA-11, CA-13—CA-17) were grown to form yeast cells and hyphal cells respectively, and the genomic DNA was extracted. Then ERGll was amplified with polymerase chain reaction (PCR) technology and cleaved by two restriction enzymes Acc I and Mun I . The products were electrophored. Furthermore, DNA differences between both forms of five C. albicans isolates (CA-1, CA-2, CA-4, CA-6, CA-7) were compared through DNA sequencing. Bovine serum albumin (BSA) medium was used to test the activity of secreted aspartyl proteinase between the dimorphic C. albicans.Results:
1. The ERG 11 gene of all isolates had been amplified successfully. There were some differences on both the Ace I and the Mun I endonuclease maps of ERG 11 gene between the hyphal form and the yeast form of C. albicans.2. Differences on ERG11 sequence between the hyphal form and the yeast form of C.albicans were found, they were located at the positions of 1 547, 1 587 and 1 617.3. The activity of secreted aspartyl proteinase in hyphal form was significantly higher than that of yeast form of C. albicans.Conclusion:1. There are some differences on DNA sequence between the hyphal form and the yeast form of C. albicans.2. There are some differences on the activity of secreted aspartyl proteinase between the hyphal form and the yeast form of C. albicans.3. The hyphal form of C.albicans is thought to be the appropriate object in medical mycology.
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