Meng F, Kanai K, Yoshikoshi K
Graduate School of Science and Technology, Nagasaki University, Nagasaki, Japan.
Lett Appl Microbiol. 2009 Jun;48(6):770-6. doi: 10.1111/j.1472-765X.2009.02609.x. Epub 2009 Apr 1.
To screen for the existence and determine the structure of Tn916-like element in Streptococcus parauberis serotype II strains isolated from cultured Japanese flounder in western Japan.
In this study, the structure of Tn916-like element and the flanking regions were characterized by polymerase chain reaction (PCR) and inverse PCR, followed by cloning and sequencing. The Tn916-like element is 18 031 bp in length and composed of 22 ORFs. Southern blot hybridization analysis showed that the HincII-digested internal structures of Tn916-like elements yielded two patterns among S. parauberis serotype II strains. The flanking sequences were identical with the corresponding region of S. parauberis serotype I strain except for the addition of 6-bp coupling sequence (ATCATA) being adjacent to the upstream of the element.
The Tn916-like element exhibited high homology (more than 99%) with Tn916 observed in other streptococci and enterococci and was integrated in the same site of chromosome for all of the tested S. parauberis serotype II strains.
The results indicate that the Tn916-like element encoding tet(M) gene is present in all of the tested S. parauberis serotype II strains, which are disseminated in the flounder-culturing areas in western Japan.
筛选日本西部养殖牙鲆中分离出的II型副乳房链球菌菌株中是否存在类Tn916元件并确定其结构。
在本研究中，通过聚合酶链反应（PCR）和反向PCR对类Tn916元件及其侧翼区域的结构进行了表征，随后进行克隆和测序。类Tn916元件长度为18031 bp，由22个开放阅读框组成。Southern杂交分析表明，II型副乳房链球菌菌株中类Tn916元件经HincII酶切后的内部结构产生两种模式。除了元件上游相邻处添加了6个碱基对的偶联序列（ATCATA）外，侧翼序列与I型副乳房链球菌菌株的相应区域相同。
类Tn916元件与在其他链球菌和肠球菌中观察到的Tn916具有高度同源性（超过99%），并且在所有测试的II型副乳房链球菌菌株中整合到染色体的同一位置。
结果表明，编码tet(M)基因的类Tn916元件存在于所有测试的II型副乳房链球菌菌株中，这些菌株在日本西部的牙鲆养殖区传播。
