Anzai Toru, Kuwamoto Yasushi, Wada Ryuichi, Sugita Sigeo, Kakuda Tsutomu, Takai Shinji, Higuchi Tohru, Timoney John F
Epizootic Research Center, Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Kokubunji-machi, Shimotsuga-gun, Tochigi 329-0412, Japan.
Am J Vet Res. 2005 Dec;66(12):2167-71. doi: 10.2460/ajvr.2005.66.2167.
To develop a method for typing Streptococcus equi on the basis of the DNA sequence of the genes that produce an M-like protein and to compare isolates among the United States, Japan, and other countries.
S equi strains CF32, Hidaka/95/2, and NCTC9682 as well as 82 other isolates from the United States, Japan, and other countries obtained during 1975 to 2001.
DNA sequences of the structural genes ( SeM and SzPSe) that produce M-like proteins were determined for 3 representative strains to find a variable region. Variability in this region of SeM was then determined for the other isolates. Amino acid sequences were deduced and analyzed phylogenetically by use of the neighbor-joining method.
Sequence diversity was detected in the N-terminal region of SeM but not in SzPSe of the 3 representative strains. Base substitutions in the variable region of SeM varied in a nonsynonymous manner, resulting in variation in the amino acid sequence. Eighty-five isolates were categorized as 32 types of SeM on the basis of differences in the deduced amino acid sequences.
This study documented a region in the N-terminal portion of SeM that varies in a nonsynonymous manner. This information should be useful in molecular epidemiologic studies of S equi.
基于产生M样蛋白的基因的DNA序列开发一种对马链球菌进行分型的方法，并比较美国、日本和其他国家的分离株。
马链球菌菌株CF32、日高/95/2和NCTC9682，以及1975年至2001年期间从美国、日本和其他国家获得的82株其他分离株。
测定3株代表性菌株产生M样蛋白的结构基因（SeM和SzPSe）的DNA序列，以找到一个可变区。然后测定其他分离株SeM该区域的变异性。推导氨基酸序列，并使用邻接法进行系统发育分析。
在3株代表性菌株的SeM N端区域检测到序列多样性，但在SzPSe中未检测到。SeM可变区的碱基替换以非同义方式变化，导致氨基酸序列变异。根据推导的氨基酸序列差异，85株分离株被分为32种SeM类型。
本研究记录了SeM N端部分以非同义方式变化的一个区域。该信息应有助于马链球菌的分子流行病学研究。
