SEQUENCE VARIATION IN THE THERMOSTABLE DIRECT HEMOLYSIN-RELATED HEMOLYSIN (TRH) GENE OF VIBRIO-PARAHAEMOLYTICUS
SEQUENCE VARIATION IN THE THERMOSTABLE DIRECT HEMOLYSIN-RELATED HEMOLYSIN (TRH) GENE OF VIBRIO-PARAHAEMOLYTICUS
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DOI：
10.1128/aem.58.8.2449-2457.1992
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发表时间：
1992-08-01
影响因子：
4.4
通讯作者：
NISHIBUCHI, M
中科院分区：
文献类型：
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作者：
KISHISHITA, M;MATSUOKA, N;NISHIBUCHI, M
我们以前用基因探针(H.Shirai，H.Ito，T.Hirayama，Y.Nakamoto，N.Nakabayashi，K.Kumagai，Y.Takeda和M.Nishibuhi)进行的分子流行病学研究，感染。伊蒙。58：3568-3573,1990)证明编码一种耐热的直接溶血素相关溶血素的基因(Trh)与副溶血性弧菌的临床菌株有很强的相关性。上述研究中观察到的菌株间杂交信号强度的差异也表明trh基因是IR。不同的菌株可能具有明显不同的核苷酸序列。为了评估与trh基因特异性DNA探针杂交信号很弱的稀有环境菌株的公共卫生意义，本研究从其中一株环境菌株中克隆了trh-like序列，并测定了其核苷酸序列。在克隆的序列中检测到一个溶血素基因(Trh2)，与trh基因(新命名为trh1)的同源性为84%，与编码耐热直接溶血素的基因(Tdh)的同源性为54.8~68.8%。Trh2基因产物表现出与trh1基因产物不同的对各种动物红细胞的溶血活性。Trh2基因产物与trh1和tdh基因产物抗原性相关(部分相同)。用trh1和trh2特异的DNA探针进行DNA菌落杂交和Southern杂交分析表明，具有不同杂交信号的trh1探针阳性菌株可聚为trh1和trh2亚群。此外，与寡核苷酸探针的杂交分析显示，trh1和trh2基因序列在不同菌株之间存在显著差异。属于trh2组的基因不仅在罕见的环境菌株中被检测到，而且在相当数量的临床菌株中也被检测到。我们的结论是，携带trh1和trh2的菌株都应该被认为是潜在的毒力。
Our previous molecular epidemiologic study with gene probes (H. Shirai, H. Ito, T. Hirayama, Y. Nakamoto, N. Nakabayashi, K. Kumagai, Y. Takeda, and M. Nishibuchi, Infect. Immun. 58:3568-3573, 1990) demonstrated that the gene (trh) encoding a thermostable direct hemolysin-related hemolysin was strongly associated with clinical strains of Vibrio parahaemolyticus. Strain-to-strain variation in the intensities of the hybridization signals observed in the above study also suggested that the trh genes ir. different strains may have significantly divergent nucleotide sequences. To assess the public health significance of the rare environmental strains which exhibited very weak hybridization signals with the trh gene-specific DNA probe, the trh-like sequence was cloned from one of the environmental strains and the nucleotide sequence was determined in this study. A hemolysin gene (trh2) which was 84% homologous to the trh gene (newly named trh1) and 54.8 to 68.8% homologous to the genes (tdh) encoding thermostable direct hemolysins was detected in the cloned sequence. The trh2 gene product showed a profile of hemolytic activities against various animal erythrocytes different from that of the trh1 gene product. The trh2 gene product was antigenically related (partially identical) to the trh1 and tdh gene products. DNA colony blot and Southern blot hybridization analyses with trh1- and trh2-specific DNA probes showed that the trh1 probe-positive strains exhibiting hybridization signals with varying intensities could be clustered into trh1 and trh2 subgroups. In addition, hybridization analysis with oligonucleotide probes demonstrated significant strain-to-strain variation in the trh1 and trh2 gene sequences. The gene belonging to the trh2 group was detected not only in rare environmental strains but also in a significant number of clinical strains. We conclude that both the trh1- and trh2-carrying strains should be considered potentially virulent.