Proposal of the concept of escape behavior from the predators in the bacterial kingdom

2015 Fiscal Year Final Research Report

• Project/Area Number: 24370013
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Ecology/Environment
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: Matsuura Katsumi 首都大学東京, 理工学研究科, 教授 (30181689)
• Co-Investigator(Renkei-kenkyūsha): HARUTA Shin 首都大学東京, 理工学研究科, 准教授 (50359642)
• Research Collaborator: HANADA Satoshi 首都大学東京, 理工学研究科, 教授 (10357791) ; MOROHOSHI Sho 首都大学東京, 理工学研究科, 客員研究員 ; FUKUSHIMA Shunichi 首都大学東京, 理工学研究科, 大学院生
• Project Period (FY): 2012-04-01 – 2016-03-31
• Keywords: 微生物群集 / 光合成細菌 / Chloroflexus / 滑走運動 / 捕食 / タンパク質分解酵素 / プロテアーゼ / 逃避行動

Outline of Final Research Achievements

Certain bacteria secrete lytic enzymes to kill other bacteria for prey. Such bacteria are called predators. In this study, we proposed the existence of an escape behavior from predators in the bacterial kingdom for the first time. The filamentous gliding bacterium (Chloroflexus aggregans) is a thermophilic unoxygenic photosynthesis bacterium. The bacterial cells move away or escape from protease of low concentration, which are secreted from co-existed heterotrophic bacteria. When the concentration of the protease is high, the photosynthetic bacteria are lysed for the prey of the protease-secreting bacteria. When the escape behavior is observed, some peptides of molecular mass of less than 1,500 were released from the photosynthetic bacteria, suggesting that they are involved in the escape behavior. Gliding-motility mechanism for the escape was also studied, and we suggest a cell surface structure moves along the longer axis of the cells with a similar rate of gliding motility.

Free Research Field

環境微生物学