Functional mechanisms of branched chain polyamines in thermophiles

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02112
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38020:Applied microbiology-related
• Research Institution: Kwansei Gakuin University
• Principal Investigator: Fujiwara Shinsuke 関西学院大学, 生命環境学部, 教授 (90263219)
• Co-Investigator(Kenkyū-buntansha): 福田 青郎 関西学院大学, 生命環境学部, 研究員 (30421283)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: アーキア / ポリアミン / 超好熱菌

Outline of Final Research Achievements

Hyperthermophiles possess branched-chain polyamines (BCPAs). In this study, the biological role of BCPA was analyzed using Thermococcus kodakarensis. In the cytoplasm of T. kodakarensis, BCPA is detected in chromosomal DNA and the membrane fraction, particularly in stationary-phase cells. BCPA appears to be crucial for survival under environmental stress, as BCPA-deficient mutants did not survive repeated cooling stress. The expression of several genes, including the hydrogenase gene hyhL, was repressed in the mutant strain, indicating that hyhL expression is regulated at the post-transcriptional level. The highly positive charge properties of BCPA were also investigated, and BCPA-immobilized micro- and nano-beads were constructed. BCPA magnetic micro-beads efficiently recovered nucleic acids, and BCPA-immobilized gold nanoparticles exhibited significant antibacterial activity against Gram-positive bacteria.

Free Research Field

微生物学

Academic Significance and Societal Importance of the Research Achievements

超好熱菌は、生命の起源に最も近い現存生物と考えられている。超好熱菌のみが有する分岐鎖ポリアミンの機能解明は、生命誕生の仕組みを考える上でも意義深い。本研究はThermococcus kodakarensisを用い、分岐鎖ポリアミンを合成できない変異株を構築し、野生株と比較することで、本分子が温度変化の激しい環境で生き残るために必須の成分であることを明らかにした。また、分岐鎖ポリアミンは、核酸への親和性が高く、その固定化磁気ビーズは核酸回収に利用でき、グラム陽性菌に抗菌性を示すとともに枯草菌胞子の発芽も抑制した。極度な塩基性と特殊な構造を持つ分岐鎖ポリアミンには様々な利用性があることが示された。