title: Physiological responses of Microcystis aeruginosa against the algicidal bacterium Pseudomonas aeruginosa.
abstract: Proliferation of cyanobacteria in aquatic ecosystems has caused water security problems throughout the world. Our preliminary study has showed that Pseudomonas aeruginosa can inhibit the growth of cyanobacterium, Microcystis aeruginosa. In order to explore the inhibitory mechanism of P. aeruginosa on the cell growth and synthesis of intracellular substances of M. aeruginosa, concentrations of Chlorophyll-a, intracellular protein, carbohydrate, enzyme activities and ion metabolism of M. aeruginosa, were investigated. The results indicated that 83.84% algicidal efficiency of P. aeruginosa was achieved after treatment for 7 days. The strain inhibited the reproduction of M. aeruginosa by impeding the synthesis of intracellular protein and carbohydrate of cyanobacterium, and only a very small part of intracellular protein and carbohydrate was detected after exposure to P. aeruginosa for 5 days. P. aeruginosa caused the alteration of intracellular antioxidant enzyme activity of M. aeruginosa, such as catalase, peroxidase. The accumulation of malondialdehyde aggravated membrane injury after treatment for 3 days. P. aeruginosa also affected the ion metabolism of cyanobacteria. The release of Na(+) and Cl(-) was significantly enhanced while the uptake of K(+), Ca(2+), Mg(2+), NO3(-) and SO4(2)(-) decreased. Surface morphology and intracellular structure of cyanobacteria and bacterial cells changed dramatically over time as evidenced by electron microscope (SEM) and transmission electron microscope (TEM) analysis. These results revealed that the algicidal activity of P. aeruginosa was primarily due to the fermentation liquid of P. aeruginosa that impeded the synthesis of intracellular protein and carbohydrate, and damaged the cell membrane through membrane lipid peroxidation.
authors: Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou 510006,Guangdong, China.
authors: Su
authors: S
authors: Zhou
authors: Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou 510006,Guangdong, China. Electronic address: huayin@scut.edu.cn.
authors: Hua
authors: H
authors: Yin
authors: Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou 510006,Guangdong, China.
authors: Shaoyu
authors: S
authors: Tang
authors: Department of Chemistry, Jinan University, Guangzhou 510632, Guangdong, China.
authors: Hui
authors: H
authors: Peng
authors: Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou 510006,Guangdong, China.
authors: Donggao
authors: D
authors: Yin
authors: Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou 510006,Guangdong, China.
authors: Yixuan
authors: Y
authors: Yang
authors: Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou 510006,Guangdong, China.
authors: Zehua
authors: Z
authors: Liu
authors: Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou 510006,Guangdong, China.
authors: Zhi
authors: Z
authors: Dang
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001673:Biodegradation, Environmental; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D007501:Iron / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D046931:Microcystis / Q000254:growth & development / Q000502:physiology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D009195:Peroxidase / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000378:metabolism / Q000502:physiology*
chemical_list: D000975:Antioxidants; D002734:Chlorophyll; D008315:Malondialdehyde; D007501:Iron; D009195:Peroxidase; D000077194:Chlorophyll A
keywords: Algicidal mechanism; Ion metabolism; Microcystis aeruginosa; Microstructure; Physiological responses; Pseudomonas aeruginosa