致病性大腸桿菌系統生物學

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國立成功大學「邁向頂尖大學計畫」

  延攬優秀人才工作報告表

NCKU’s “Aim for the Top University Project” Work Report Form for Distinguished Scholars □續聘continuation of employment ■離職resignation

100年7月13日更新

受聘者姓名

Name of the Employee

橋本昌征

The project title of research, teaching, technology development and management

致病性大腸桿菌系統生物學 計畫主持人 （申請單位主管） Project Investigator (Head of Department/Center) 鄧景浩 補助延聘編號

Grant Number HUA 107-25-7-116

一、 研究、教學、科技研發與管理工作全程經過概述。（由受聘人填寫）

Please summarize the entire research, teaching, or science and technology R&D and management work process (To be completed by the employee)

A bacterial cell is covered with peptidoglycan (PG) sacculus, which behaves as an exoskeleton of the cell, and protects the cell from environmental stresses. However, PG sacculus must change its shape during cell proliferation keeping with the sacculus. To change the shape, not only synthesis but also reassemble of the structure is necessary. Therefore, Dr. Hashimoto is interested in peptidoglycan degrading enzymes. Previously, he demonstrated that Bacillus subtilis cells depleted two PG degrading enzymes (lytE and cwlO) exhibit synthetic lethality and defective in cell elongation. These PG degrading enzymes are DL-endopeptidase (DLEPase), which digest the linkage of D-γ-glutamyl-meso-diaminopimelic acid in PG. He had also revealed that these two enzymes localize at lateral cell wall, and the synthetic lethality is caused by the lack of DLEPase activity at sidewall. He also demonstrated that the DLPEase at lateral cell wall could replace to DDEPase from B. subtilis (CwlP-M23) and also E. coli (YebA). However, other cell wall degrading enzymes could not suppress the lytE cwlO synthetic lethality. Then he suggest that degrading close to the peptide bridge in PG is important for cell wall reassemble. In the last one year, he addresses to develop a peptidyl inhibitor for LytE and CwlO. As described above, these enzymes are essential for cell growth, therefore the inhibitor will behave as an antibiotic. He designed an oligo-peptide referring proteinous inhibitor for LytE and CwlO, which is IseA from

B. subtilis uncovered by Dr. Hashimoto. The oligo-peptide inhibits the LytE and CwlO in vitro,

and hinders bacterial growth. The peptide will be a lead compound for a novel antibiotic.

Escherichia coli comprised of strains showing different phenotypes, which are

non-pathogenic, enterohemorrhagic, uronon-pathogenic, and so on. Such phenotypic features between strains are resulted from different genomic structure. From genome comparison of many E. coli strains, it has been revealed that bacteria genome shows mosaic structure and is comprised of core-genome and accessary- core-genome, which involves in the common feature of the species and the phenotypes specific to the strains, respectively. These accessary genes characterizing the strain are clustered (genomic island) and are acquired by horizontal gene transfer. Then, our question is that, does the acquisition of accessary genome happen at random? Is the genomic evolution only affected by the selective pressure from the environment?

Restriction-modification in bacteria is a kind of immune system to exclude foreign DNA. In a bacterial cell, foreign DNA is digested by the restriction enzyme, but own DNA is protected by DNA methylation. Furthermore, restriction enzymes specifically digesting methylated DNA sequence (T4RE) is identified in some bacteria. A T4RE and a DNA methyltransferase, which methylates the recognition sequence of the T4RE, cannot co-exist in a cell, because their genomic

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DNA would be methylated and digested. Then, we are investigating whether the conflict affects the horizontal gene transfer and genomic evolution using uropathogenic E. coli as a model.

McrBC is a T4RE in E. coli recognizing (G/A)mC-N40-3000-(G/A)mC. A plasmid expressing

McrBC is introduced to 83 of clinically isolated urinary tract infectious (UTI) E. coli, and 50 E.

coli strains isolated from fecal. The frequency of lethality by the conflict is significantly higher in

the UTI isolates than fecal isolates. It suggests that the distribution of DNA methyltransferase shown the conflict is higher in UTI E. coli. Nine DNA metyltransferase genes were specifically found in the strains shown conflict, and the methylation sites of them were determined to confirm the conflict. In the same manner, we isolated a novel T4RE homologous to Mrr from E. coli K-12. The enzyme also showed higher frequency for the conflict in pathogenic strains than commensal strains. The result further support that T4RE involved in pathogenisity.

We want to further investigate whether the conflict affects pathogenic evolution in UPEC model. Then, we are going to score the pathogenicity of the 133 E. coli strains using

Caenorhabditis elegans as an infection model. In addition, genomic comparison of the 133 strains

will be carried out to found a relation between the conflict and factors showing higher pathogenicity.

二、研究或教學或科技研發與管理成效評估（由計畫主持人或單位主管填寫）

Please evaluate the performance of research, teaching or science and technology R&D and management Work: (To be completed by Project Investigator or Head of Department/Center)

橋本博士在此聘期內參與研究以及教學工作，其成效良好。他所參與教學部分，以英文教學。不僅 將其專長教授學生，學生也反應良好。此外，在研究方面，進展順利。橋本博士也申請科技部計畫， 並獲得研究經費補助。

(1)是否達到延攬預期目標？

Has the expected goal of recruitment been achieved?

橋本博士在教學及研究上皆有不錯進展。已經達到延攬的預期目標。 (2)研究或教學或科技研發與管理的方法、專業知識及進度如何？

What are the methods, professional knowledge, and progress of the research, teaching, or R&D and management work?

橋本博士有高水準的專業知識。 他所參與教學部分，以英文教學。不僅將其專長教授學生，學生 也反應良好。此外，在研究方面，進展順利。橋本博士也申請科技部計畫，並獲得研究經費補助。 (3)受延攬人之研究或教學或科技研發與管理成果對該計畫(或貴單位)助益如何？

How have the research, teaching, or R&D and management results of the employed person given benefit to the project (or your unit)?

有橋本博士的參與，不僅充實本單位師資也加速研究計畫執行的進度。 (4)受延攬人於補助期間對貴單位或國內相關學術科技領域助益如何？

How has the employed person, during his or her term of employment, benefited your unit or the relevant domestic academic field?

於補助期間，橋本博士申請科技部計畫，已被審核通過。其科技部計畫將在本單位執行，其執行經費 及未來的執行成果將對本單位學術科技研究很有助益。

(5)具體工作績效或研究或教學或科技研發與管理成果：

Please describe the specific work performance, or the results of research, teaching, or R&D and management work:

橋本博士參與了醫學院的專題討論、傳染性疾病與微生物導論、高等細菌學、分子醫學特論等課程。 其在大腸桿菌研究計畫中，發現了幾個與 NotI resistance 相關的基因，正在探討這些基因是否與細 菌致病力有關。此研究進行順利。

(6)是否續聘受聘人? Will you continue hiring the employed person? □續聘Yes □■不續聘No

※ 此報告表篇幅以三～四頁為原則。This report form should be limited to 3-4 pages in principle. ※ 此表格可上延攬優秀人才成果報告繳交說明網頁下載。