Oxidative responses and scope for growth of brackish water clam Corbicula japonica exposed to environmental stress

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06615
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Civil and environmental engineering
• Research Institution: Ibaraki University
• Principal Investigator: Fujita Masafumi 茨城大学, 理工学研究科(工学野), 准教授 (60362084)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: ヤマトシジミ / 酸化ストレスマーカー / 成長力 / 汽水

Outline of Final Research Achievements

The variation in ORAC was relatively low in brackish water clam Corbicula japonica with shell lengths between 19～25mm. Gills were more appropriate organs for detecting antioxidant effects. A simple modified method for scope for growth (SFG) assay of C. japonica was developed using the carbon mass balance estimated from three experiments: a clearance experiment, an excretion experiment and a respiration experiment. Oxidative stress as biochemical-level response and SFG as individual-level response were examined in C. japonica exposed to 5× dilution municipal wastewater and its components. An integrated biomarker responses (IBR) index estimating from the responses of oxidative stress makers used revealed that the most significant stressor was dissolved matters in wastewater. Further, a negative correlation was found between IBR and SFG. We conclude that SFG can be a useful indicator to interpret the response of oxidative stress markers in C. japonica.

Free Research Field

水環境工学

Academic Significance and Societal Importance of the Research Achievements

汽水性二枚貝ヤマトシジミの酸化ストレスマーカーを評価するうえで、個体間のばらつきを抑えられる殻長の範囲を明らかにした。ヤマトシジミの成長力を、従来のエネルギーベースではなく、炭素ベースで簡便に評価できる手法を確立した。酸化ストレスマーカーと成長力との間に負の相関があることが見出されたことから、個体レベルの応答である成長力を用いることにより、生化学レベルの酸化ストレスマーカーの応答を解釈できる見通しが立ったと言える。