title: Evaluating the effects of allelochemical ferulic acid on Microcystis aeruginosa by pulse-amplitude-modulated (PAM) fluorometry and flow cytometry.
abstract: We investigated the effects of allelochemical ferulic acid (FA) on a series of physiological and biochemical processes of blue-green algae Microcystis aeruginosa, in order to find sensitive diagnostic variables for allelopathic effects. Algal cell density was significantly suppressed by FA (0.31-5.17 mM) only after 48 h exposure. Inhibitions of photosynthetic parameters (F(v)/F(m) and F(v)'/F(m)') occurred more rapidly than cell growth, and the stimulation of non-photochemical quenching was observed as a feed-back mechanisms induced by photosystem II blockage, determining by PAM fluorometry. Inhibitions on esterase activity, membrane potential and integrity, as well as disturbance on cell size, were all detected by flow cytometry with specific fluorescent markers, although exhibiting varied sensitivities. Membrane potential and esterase activity were identified as the most sensitive parameters (with relatively lower EC50 values), and responded more rapidly (significantly inhibited only after 8 h exposure) than photosynthetic parameters and cell growth, thus may be the primary responses of cyanobacteria to FA exposure. The use of PAM fluorometry and flow cytometry for rapid assessment of those sensitive variables may contribute to future mechanistic studies of allolepathic effects on phytoplankton.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
authors.forename: Ming
authors.initials: M
authors.lastname: Hua
authors.affiliation: Nanjing Institute of Geography and Limnology, Chinese Academy of Science, 210093, Jiangsu, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Nanjing Institute of Geography and Limnology, Chinese Academy of Science, 210093, Jiangsu, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
authors.forename: Qi-Ming
authors.initials: QM
authors.lastname: Xian
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China. Electronic address: yindq@tongji.edu.cn.
authors.forename: Da-Qiang
authors.initials: DQ
authors.lastname: Yin
mesh_terms: D003373:Coumaric Acids / Q000494:pharmacology*; D004950:Esterases / Q000378:metabolism; D005434:Flow Cytometry; D005470:Fluorometry; D046931:Microcystis / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D010675:Pheromones / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects; D045332:Photosystem II Protein Complex / Q000187:drug effects; D010839:Phytoplankton / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D003373:Coumaric Acids; D010675:Pheromones; D045332:Photosystem II Protein Complex; C004999:ferulic acid; D004950:Esterases
keywords: Allelochemical; Esterase enzyme; Feruliac acid; Flow cytometry; PAM fluorometry; Photosystem