猪链球菌谷氨酸脱氢酶基因的克隆和序列分析

对猪链球菌2型、7型、9型的标准菌株和7株猪链球菌2型分离菌的谷氨酸脱氢酶(GDH)基因进行PCR扩增,经回收纯化后克隆到PMD18-T载体,筛选阳性克隆菌后测序并对其进行序列分析。结果,PCR扩增出1300bp左右的片段,包括GDH基因的整个开放阅读框,而测序结果表明,其序列与GenBank中的猪链球菌GDH基因序列一致,进一步序列分析表明,GDH的核苷酸序列在相同血清型之间同源性高达99%以上,而在不同血清型之间的同源型也达到了96%以上,而其氨基酸序列同源性则都在99%以上,且都具有GDH1型家族的功能区域。说明猪链球菌GDH基因及其蛋白具有高度的保守性,为进一步研究与应用提供了重要依据。

Cloning and sequence analysis of gene encoding the glutamate dehydrogenase of Streptococcus suis

The GDH gene encoding the glutamate dehydrogenase was amplified from Streptococcus suis serotype 2,7,9 and seven strains of S. suis serotype 2 by PCR. The PCR products were cloned to PMD18-T vector after purifying. The positive recombinant plasmids of pMD18-T-GDH were sequenced and subjected to sequence analysis.The results showed that about 1.3kb fragment was amplified,including the whole open reading frame of GDH gene,and its sequence was identical with those in the GenBank. Sequence comparisons showed that the homologies of GDH gene were over 99% among the same serum type and more than 96% among different serum type,but their homologies of amino acid were all above 99%,and had function area of GDH 1 type family. It was suggested that the GDH gene and its protein were highly conservative and the study offered the important basis for its further study and application.