Identification and functional analysis of resistance factors for enterohemorrhagic Escherichia coli-specific defense mechanisms

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K07474
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 49050:Bacteriology-related
• Research Institution: Chiba University
• Principal Investigator: Shimizu Takeshi 千葉大学, 大学院医学研究院, 准教授 (70312840)
• Co-Investigator(Kenkyū-buntansha): 濱端 崇 国立研究開発法人国立国際医療研究センター, その他部局等, 細菌感染研究室長 (40311427)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 腸管出血性大腸菌 / 生体防御機構抵抗因子 / NO抵抗性 / プラスミド

Outline of Final Research Achievements

To identify EHEC-specific defense mechanism resistance factors, a plasmid library was constructed using EHEC genomic DNA, NO treatment was performed on the E. coli library, NO-resistant clones were enriched, and the insert DNAs of the plasmids retained by these clones were amplified by PCR, The nucleotide sequence was determined. The results revealed that the gene responsible for NO resistance is the RNA-binding rop gene harbored by pOSAK1, an O157-specific plasmid. rop protein may be involved in the enhancement of EHEC's small RNA-mediated biological defense resistance mechanism, but the details of its mechanism of action remain unclear. However, the details of the mechanism of action are not yet clear. In the future, we will elucidate the details of the mechanism by which Rop protein enhances the defense resistance of EHEC.

Free Research Field

病原細菌学

Academic Significance and Societal Importance of the Research Achievements

今回の研究成果はEHECだけではなく、他の大腸菌にも当てはまる未知の宿主防御機構抵抗因子を同定したことに意義がある。特に、その抵抗因子の遺伝子はプラスミドにコードされていることから、大腸菌から大腸菌、あるいは他の細菌に水平伝達することによる、病原性増強機構であることが言える。従来、プラスミドの問題点として、薬剤耐性遺伝子の細菌間の水平伝達であったが、薬剤耐性だけではなく、宿主防御機構抵抗因子としての問題が明らかにできた。このことは今後の病原細菌の病原性増強機構を考える上で重要なことである。