title: Cell death in a harmful algal bloom causing species Alexandrium tamarense upon an algicidal bacterium induction.
abstract: Harmful algal blooms occur throughout the world, destroying aquatic ecosystems and threatening human health. The culture supernatant of the marine algicidal bacteria DHQ25 was able to lysis dinoflagellate Alexandrium tamarense. Loss of photosynthetic pigments, accompanied by a decline in Photosystem II (PSII) photochemical efficiency (Fv/Fm), in A. tamarense was detected under bacterial supernatant stress. Transmission electron microscope analysis showed obvious morphological modifications of chloroplast dismantling as a part of the algicidal process. The PSII electron transport chain was seriously blocked, with its reaction center damaged. This damage was detected in a relative transcriptional level of psbA and psbD genes, which encode the D1 and D2 proteins in the PSII reaction center. And the block in the electron transport chain of PSII might generate excessive reactive oxygen species (ROS) which could destroy the membrane system and pigment synthesis and activated enzymic antioxidant systems including superoxide dismutase (SOD) and catalase (CAT). This study indicated that marine bacteria with indirect algicidal activity played an important role in the changes of photosynthetic process in a harmful algal bloom species.
authors: State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, 422, Siming Nan Road, Xiamen, 361005, China.
authors: Huajun
authors: H
authors: Zhang
authors: Jinglin
authors: J
authors: Lv
authors: Yun
authors: Y
authors: Peng
authors: Su
authors: S
authors: Zhang
authors: Xinli
authors: X
authors: An
authors: Hong
authors: H
authors: Xu
authors: Jun
authors: J
authors: Zhang
authors: Yun
authors: Y
authors: Tian
authors: Wei
authors: W
authors: Zheng
authors: Tianling
authors: T
authors: Zheng
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D004141:Dinoflagellida / Q000166:cytology / Q000378:metabolism*; D057097:Harmful Algal Bloom / Q000502:physiology*; D018384:Oxidative Stress / Q000502:physiology; D010788:Photosynthesis / Q000502:physiology; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D013482:Superoxide Dismutase