Genotyping of a gene cluster for production of colibactin and in vitro genotoxicity analysis of Escherichia coli strains obtained from the Japan Collection of Microorganisms
Genotyping of a gene cluster for production of colibactin and in vitro genotoxicity analysis of Escherichia coli strains obtained from the Japan Collection of Microorganisms
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DOI：
10.1186/s41021-020-00149-z
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发表时间：
2020-03-11
影响因子：
1.7
通讯作者：
Watanabe, Kenji
中科院分区：
文献类型：
--
作者：
Kawanishi, Masanobu;Shimohara, Chiaki;Watanabe, Kenji
介绍大肠杆菌素是一种小的遗传毒性分子产生的肠道细菌，包括某些大肠杆菌（E。大肠杆菌）菌株。这种聚酮肽基因毒素被认为有助于结直肠癌的发展。产大肠杆菌素（clb（+））的微生物具有54-组氨酸酶基因组岛（clb基因簇）。本研究对大肠杆菌clb基因簇进行了基因分型，以了解clb基因簇的分布情况。大肠杆菌菌株随机选自日本微生物保藏中心，RIKEN BRC，日本。结果-分析显示，两个6株具有clb基因簇。这些clb（+）菌株JCM 5263和JCM 5491在使用啮齿动物CHO AA 8细胞的体外微核（MN）试验中诱导遗传毒性。由于JCM 5263对MN的诱导水平高，因此用该菌株的细胞提取物进行细菌umu试验，表明该提取物在umu试验细菌中具有SOS诱导效力。结论clb基因簇在自然界中广泛分布，clb（+）E.具有遗传毒性的大肠杆菌在微生物中并不罕见。
Introduction Colibactin is a small genotoxic molecule produced by enteric bacteria, including certain Escherichia coli (E. coli) strains harbored in the human large intestine. This polyketide-peptide genotoxin is considered to contribute to the development of colorectal cancer. The colibactin-producing (clb(+)) microorganisms possess a 54-kilobase genomic island (clb gene cluster). In the present study, to assess the distribution of the clb gene cluster, genotyping analysis was carried out among E. coli strains randomly chosen from the Japan Collection of Microorganisms, RIKEN BRC, Japan. Findings The analysis revealed that two of six strains possessed a clb gene cluster. These clb(+) strains JCM5263 and JCM5491 induced genotoxicity in in vitro micronucleus (MN) tests using rodent CHO AA8 cells. Since the induction level of MN by JCM5263 was high, a bacterial umu test was carried out with a cell extract of the strain, revealing that the extract had SOS-inducing potency in the umu tester bacterium. Conclusion These results support the observations that the clb gene cluster is widely distributed in nature and clb(+)E. coli having genotoxic potencies is not rare among microorganisms.