Microcystin accumulation and biochemical responses in the edible clam Corbiculaleana P. exposed to cyanobacterial crude extract.
We investigated the accumulation and effects of cyanobacterial crude extract (CCE) containing microcystins (MCs) on the edible clam Corbiculaleana P. Toxic effects were evaluated through the activity of antioxidant and detoxification enzymes: catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferases (GSTs) from gills, foot, mantle and remaining soft tissues. Clams were exposed to CCE containing 400μg MC-LReq/L for 10days and were then kept in toxin-free water for 5days. Clam accumulated MCs (up to 3.41±0.63μg/g dry weight (DW) of unbound MC and 0.31±0.013μg/g DW of covalently bound MC). Detoxification and antioxidant enzymes in different organs responded differently to CCE during the experiment. The activity of SOD, CAT, and GST in the gills and mantle increased in MC-treated clams. In contrast, CAT and GST activity was significantly inhibited in the foot and mostly only slightly changed in the remaining tissues. The responses of biotransformation, antioxidant enzyme activity to CCE and the fast elimination of MCs during depuration help to explain how the clam can survive for long periods (over a week) during the decay of toxic cyanobacterial blooms in nature.
Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Vietnam Academy of Science and Technology (VAST), Institute of Tropical Biology, 85 Tran Quoc Toan St., Dist. 3, Ho Chi Minh City, Viet Nam. Electronic address: thanhluupham@gmail.com.
Thanh-Luu
TL
Pham
Faculty of Life Sciences, Toyo University, Ora-gun, Gunma 374-0193, Japan.
Kazuya
K
Shimizu
Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Ayako
A
Kanazawa
College of Chemical and Environmental Engineering, Shandong, University of Science and Technology, Qingdao 266590, China.
Yu
Y
Gao
Ho Chi Minh City University of Technology, 268 Ly Thuong Kiet St., Dist. 10, Ho Chi Minh City, Viet Nam.
Thanh-Son
TS
Dao
Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Motoo
M
Utsumi
D000818:Animals; D049872:Bivalvia / Q000378:metabolism / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D000458:Cyanobacteria; D005880:Gills / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D057097:Harmful Algal Bloom; D052998:Microcystins / Q000378:metabolism* / Q000633:toxicity; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity
D052998:Microcystins; D014874:Water Pollutants, Chemical; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase
Aqueous extracts; Bioaccumulation; Covalently bound microcystins; Cyanotoxins