Are Helicobacter catorum and Helicobacter delphinicola involved in the gastric diseases of dolphins? -VacA as an indicator-

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15598
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 40040:Aquatic life science-related
• Research Institution: Nihon University (2021-2022); Mie University (2020)
• Principal Investigator: SEGAWA Takao 日本大学, 生物資源科学部, 助教 (50755600)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: イルカ / ヘリコバクター / VacA

Outline of Final Research Achievements

In order to evaluate the virulence of Helicobacter cetorum (HC) and Helicobacter delphinicola (HD) to dolphins, we attempted to identify the receptors for the Vac-like toxins produced by both species. We found that some HC exhibits sphingomyelin-mediated toxin activity. HD showed VacA-like toxin activity in some culture cells, but the gene sequence has not been determined. We attempted to identify that vacA-like genes by whole genome analysis of HD, and succeeded in identifying the vacA-like gene. In the future, we plan to perform functional analysis of the vacA-like gene predicted from the HD genome sequence.

Free Research Field

海洋細菌学

Academic Significance and Societal Importance of the Research Achievements

イルカにおいて胃潰瘍や胃炎は難治性疾患の一つである．しかし，その主原因は解明されていないため，適切な診断法や治療・予防法の開発が進まず，多くの飼育下イルカが胃病変を患っている現状がある．本研究により一部のHCがイルカに対して病原性を示す可能性がある結果が得られた．今後病原性を示すHCを特異的に検出する簡易診断法や適切な治療・予防法が開発することで世界中で飼育されているイルカを今より健康的に飼育することが可能になる．従って本研究は，世界的にイルカの動物愛護に関して批判の声が多い日本が世界に先駆けて発信できる成果になると期待される．