Analysis of survival strategy and pathogenic factors of bacteria using silk worm infection model

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K07556
• 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: Yamaguchi University
• Principal Investigator: Shimizu Takashi 山口大学, 共同獣医学部, 准教授 (40320155)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 野兎病 / Francisella / カイコ / 細胞内増殖 / CRISPR

Outline of Final Research Achievements

This study aimed to elucidate the mechanisms of growth within arthropods (silkworms) and host cells (including humans), using Francisella as a model for arthropod-borne pathogens.
The results revealed that the mltA gene of Francisella is essential for thebacteri to evade the arthropod immune system and to proliferate within arthropods. The slt gene was also found to be important for growth in human cells, bypassing the immune system and autophagy.
In addition, we used CRISPR gene editing to identify several candidate of host factors that are important for the infection of Francisella.

Free Research Field

細菌学

Academic Significance and Societal Importance of the Research Achievements

近年の地球温暖化の影響で節足動物媒介性の感染症は拡大している。しかしながら節足動物媒介細菌感染症において、節足動物における最近の生存戦略や病原性への影響は殆ど解明されていない。本研究ではマダニ媒介性の野兎病菌（Francisella tularensis）を細菌モデルとして、カイコ（Bombyx mori）を節足動物モデルとして使用することにより、病原性細菌の節足動物内での生存戦略、ヒトを含む宿主細胞内での増殖メカニズムの一端を解明することに成功した。