Study of ecosystem assessment for oxidative damaged base by oxidative radical reaction

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K12607
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental impact assessment
• Research Institution: Ibaraki University
• Principal Investigator: KURUSU Yasurou 茨城大学, 農学部, 教授 (60272118)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 酸化損傷塩基 / 酸化ラジカル反応 / 自然突然変異

Outline of Final Research Achievements

One of the most lesions in DNA caused by reactive oxygen species (ROS) is the oxidized base 7,8-dihydro-8-oxoguanine (8-oxoG). The product of three of the Escherichia coli mut genes, mutM, mutY, and mutT, are devoted exclusively to preventing mutations due to 8-oxoG and are important components of the defense against this type of oxidative damage. However, other bacteria for DNA repair systems to prevent 8-oxoG such as MutT are unclear. Here, we used some strains, such as an Bacillus subtilis, Lactobacillus reuteri, Pseudoalteromonas sp from deep sea, Synechocystis sp. PCC6803, and E. coli as a control. We measured the amount of 8-oxoG in chromosomal DNA. Also, cells highly accumulated 8-oxoG in DNA at low temperature than at appropriate temperature in all of bacteria. These results indicated that accumulation of 8-oxoG by ROS is highly active in exponential growth and at low temperature and prevention of DNA mutation by 8-oxoG are due to MutY and MutM rather than MutT.

Free Research Field

微生物学

Academic Significance and Societal Importance of the Research Achievements

これまで、生物進化の原動力は、ウィルス、トランスポゾン、プラスミド等による遺伝子の水平伝搬、すなわち外的要因を中心に研究されてきた。本研究は、細胞内酸化ラジカル反応により生成する酸化損傷塩基8OHdGを細胞内変異原、すなわち内的要因として位置付け、8-OHdGを生物進化の新たな指標として、そのポテンシャルを評価する点に意義がある。