| Title: | Programmed cell death process in freshwater Microcystis aeruginosa and marine Phaeocystis globosa induced by a plant derived allelochemical |
| Author(s): | Xu C; Yu S; Hu J; Effiong K; Ge Z; Tang T; Xiao X; |
| Address: | "Zhejiang University, Ocean College, 1 Zheda Road, Zhoushan, Zhejiang 316000, China. Zhejiang University, Analysis Center of Agrobiology and Environmental Sciences, Hangzhou 310058, China. Zhejiang University, Ocean College, 1 Zheda Road, Zhoushan, Zhejiang 316000, China; Key Laboratory of Watershed Non-point Source Pollution Control and Water Eco-security of Ministry of Water Resources, College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address: xi@zju.edu.cn" |
| DOI: | 10.1016/j.scitotenv.2022.156055 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "Harmful algal blooms (HAB) are a serious problem worldwide. Allelochemicals from natural plants were recently thought to be promising anti-algaecide in controlling harmful algae. However, the programmed cell death (PCD) process of algae under allelopathic pressure induced by 5,4'-dihydroxyflavone (5,4'-DHF) was poorly understood. In this study, two common and worldwide distributed microalgae, Microcystis aeruginosa and Phaeocystis globosa were selected as target algae, and the PCD processes induced by 5,4'-DHF were cross-compared between the two species. Both algae species were inhibited significantly by 5,4'-DHF with the relative sensitivity of 0.11. To uncover the PCD progress systematically, signals for PCD triggering, antioxidant enzyme activity, photosynthetic ability variation, caspase-like activities and typical indicators were investigated. In both species, typical indicators of PCD - phosphatidylserine externalization and chromatin condensation - were detected. The intracellular reactive oxygen species (ROS), nitric oxide (NO) and H(2)O(2) were the potential signal molecules to stimulate PCD, and caspase-like activities were activated with an elevation of cytochrome c indicating the initiation of PCD in both species. However, P. globosa responded to 5,4'-DHF immediately after 3 h with the elevation of ROS and not in M. aeruginosa. Antioxidant enzyme activities of superoxide dismutase (SOD) and catalase (CAT) in M. aeruginosa and P. globosa also showed different patterns on day 3. Specifically, SOD activity in M. aeruginosa increased significantly while it decreased significantly in P. globosa, CAT activity in M. aeruginosa decreased significantly while it increased significantly in P. globosa (p < 0.05). Malondialdehyde (MDA) content in P. globosa increased significantly (p < 0.001) while it showed no variation in M. aeruginosa. Overall, this study is one of the earliest studies to explore the inhibition and action mechanism of plant derived flavonoids on harmful algae from the perspective of PCD, and provide new insights into the antialgal mechanism of allelochemicals" |
| Keywords: | Antioxidants/metabolism Apoptosis Caspases Fresh Water *Haptophyta/metabolism Hydrogen Peroxide *Microcystis/metabolism Pheromones Reactive Oxygen Species/metabolism Superoxide Dismutase/metabolism Allelopathy Flavonoids Hab Microcystis aeruginosa Pcd Pha; |
| Notes: | "MedlineXu, Caicai Yu, Shumiao Hu, Jing Effiong, Kokoette Ge, Zhiwei Tang, Tao Xiao, Xi eng Netherlands 2022/05/23 Sci Total Environ. 2022 Sep 10; 838(Pt 2):156055. doi: 10.1016/j.scitotenv.2022.156055. Epub 2022 May 19" |
