Kato M, Ozeki M, Kikuchi A, Kanbe T
Department of Life Sciences, Osaka Prefecture University College of Integrated Arts and Sciences, Sakai 599-8531, Japan.
Gene. 2001 Jul 11;272(1-2):275-81. doi: 10.1016/s0378-1119(01)00526-1.
We have determined the nucleotide sequences of about 55% of the region of the DNA topoisomerase II gene (approximately 2.3 kb) isolated from the pathogenic Candida species, C. dubliniensis, C. parapsilosis, C. tropicalis, C. krusei, C. kefyr, C. guilliermondii and C. lusitaniae. Evolutionary relationships among nine Candida species including those of C. albicans and C. glabrata were studied based on the DNA topoisomerase II gene. The nucleotide sequences of 2192 bp, which covered two catalytic domains, ATPase and cutting/resealing, were subjected to phylogenetic analysis. Sequence comparison and evolutionary analysis have revealed that the Candida species tested here are not monophyletic, and the two strains within the species C. tropicalis and C. parapsilosis are too diverse to be in a single species. A wide variety of divergence was observed among the functional domains of DNA topoisomerase II, suggesting that Candida species were in different evolutionary paths at least as regarding the DNA topoisomerase II gene. Sequence information and the observation on the species-specific manner of molecular evolution of DNA topoisomerase II in Candida will be applied to develop a method of identification and characterization of the Candida species in both natural and clinical isolates.
我们已经测定了从致病性念珠菌属的都柏林念珠菌、近平滑念珠菌、热带念珠菌、克鲁斯念珠菌、凯菲念珠菌、季也蒙念珠菌和葡萄牙念珠菌中分离出的DNA拓扑异构酶II基因区域（约2.3 kb）约55%的核苷酸序列。基于DNA拓扑异构酶II基因研究了包括白色念珠菌和光滑念珠菌在内的9种念珠菌之间的进化关系。对覆盖ATP酶和切割/重新封闭这两个催化结构域的2192 bp核苷酸序列进行了系统发育分析。序列比较和进化分析表明，这里测试的念珠菌物种并非单系起源，热带念珠菌和近平滑念珠菌这两个物种内的两个菌株差异太大，不能归为同一个物种。在DNA拓扑异构酶II的功能结构域之间观察到了广泛的差异，这表明至少就DNA拓扑异构酶II基因而言，念珠菌物种处于不同的进化路径。念珠菌中DNA拓扑异构酶II的序列信息以及物种特异性分子进化方式的观察结果将应用于开发一种鉴定和表征自然分离株和临床分离株中念珠菌物种的方法。
