Prevalence of cytolethal distending toxin production in Campylobacter jejuni and relatedness of Campylobacter sp cdtB genes
Prevalence of cytolethal distending toxin production in Campylobacter jejuni and relatedness of Campylobacter sp cdtB genes
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DOI：
10.1128/iai.64.6.2070-2078.1996
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发表时间：
1996-06-01
影响因子：
3.1
通讯作者：
Zeytin, H
中科院分区：
文献类型：
--
作者：
Pickett, CL;Pesci, EC;Zeytin, H
空肠弯曲杆菌产生一种称为细胞致死膨胀毒素（CDT）的毒素。对空肠弯曲菌 81-176 中编码该毒素的基因进行了克隆和测序。基因的核苷酸序列显示，存在三个基因：cdtA、cdtB和cdtC，分别编码预测大小为30,116、28,989和21,157 Da的蛋白质。所有三种蛋白均被发现与大肠杆菌 CDT 蛋白相关，但氨基酸序列却存在显着差异。所有三个基因都是 HeLa 细胞测定中毒性活性所必需的，对多种空肠弯曲菌和大肠杆菌菌株的 HeLa 细胞测定表明，大多数空肠弯曲菌菌株产生的 CDT 滴度明显高于大肠杆菌菌株。 Southern 杂交实验表明，除了一种测试的空肠弯曲菌菌株外，其余所有菌株的 6.0-kb ClaI 片段上都存在 cdtB 基因； cdtB 基因位于一个菌株的 6.9 kb ClaI 片段上。空肠弯曲菌 81-176 cdtB 探针与来自大肠杆菌菌株的 DNA 微弱杂交。空肠弯曲杆菌 81-176 cdtB 探针不与来自代表性胎儿弯曲杆菌、拉里弯曲杆菌、“upsaliensis”弯曲杆菌和豚肠弯曲杆菌菌株的 DNA 杂交，尽管 HeLa 细胞测定表明这些菌株产生 CDT。 PCR 实验表明所有这些弯曲杆菌属物种中可能存在 cdtB 序列。
Campylobacter jejuni produces a toxin called cytolethal distending toxin (CDT). The genes encoding this toxin in C. jejuni 81-176 were cloned and sequenced. The nucleotide sequence of the genes revealed that there are three genes, cdtA, cdtB, and cdtC, encoding proteins with predicted sizes of 30,116, 28,989, and 21,157 Da, respectively. All three proteins were found to be related to the Escherichia coli CDT proteins, yet the amino acid sequences have diverged significantly. All three genes were required for toxic activity in a HeLa cell assay, HeLa cell assays of a variety of C. jejuni and C. coli strains suggested that most C. jejuni strains produce significantly higher CDT titers than do C. coli strains. Southern hybridization experiments demonstrated that the cdtB gene is present on a 6.0-kb ClaI fragment in all but one of the C. jejuni strains tested; the cdtB gene was on a 6.9-kb ClaI fragment in one strain. The C. jejuni 81-176 cdtB probe hybridized weakly to DNAs from C. coli strains. The C. jejuni 81-176 cdtB probe did not hybridize to DNAs from representative C. fetus, C. lari, C. ''upsaliensis,'' and C. hyointestinalis strains, although the HeLa cell assay indicated that these strains make CDT. PCR experiments indicated the probable presence of cdtB sequences in all of these Campylobacter species.