Studies on antimicrobial peptide-mediated death of bacteria associated with pneumonia

2014 Fiscal Year Final Research Report

• Project/Area Number: 23591170
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Respiratory organ internal medicine
• Research Institution: Kurume University
• Principal Investigator: KUWANO KOICHI 久留米大学, 医学部, 教授 (60215118)
• Co-Investigator(Kenkyū-buntansha): KIDA Yutaka 久留米大学, 医学部, 講師 (30309752) ; TANI Kenji 久留米大学, 医学部, 研究員 (00614108)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 塩基性抗菌ペプチド / 抗菌活性 / 過酸化水素 / 膜透過性 / ヒドロキシラジカル / 抗菌剤 / 活性酸素

Outline of Final Research Achievements

We examined the mechanisms by which antimicrobial peptides cause cell death of bacteria. For E. coli, the levels of antimicrobial activity by the peptides were associated with the levels of increment of cell permeability induced by the peptides. Treatment of some antimicrobial peptides induced only reactive oxygen species (ROS) in E. coli. In contrast, the peptides caused increment of cell permeability as well as production of ROS in S. aureus. Furthermore the peptides induced the production of ROS, but not increment of cell permeability in mycoplasma. Scavengers of hydroxyl radical inhibited the activity of antimicrobial peptides against E. coli and mycoplasma.
Collectively, the antimicrobial peptides possess the two distinct mechanisms in the induction of bacterial cell death: increment of cell permeability and ROS production. Selection of the mechanism for the cell death was dependent on bacterial species.

Free Research Field

病原細菌と宿主の相互作用の解析