title: Microcystin-Bound Protein Patterns in Different Cultures of Microcystis aeruginosa and Field Samples.
abstract: Micocystin (MC) exists inMicrocystiscells in two different forms, free and protein-bound. We examined the dynamic change in extracellular free MCs, intracellular free MCs and protein-bound MCs in both batch cultures and semi-continuous cultures, using high performance liquid chromatography and Western blot. The results showed that the free MC per cell remained constant, while the quantity of protein-bound MCs increased with the growth ofMicrocystiscells in both kinds of culture. Significant changes in the dominant MC-bound proteins occurred in the late exponential growth phase of batch cultures, while the dominant MC-bound proteins in semi-continuous cultures remained the same. In field samples collected at different months in Lake Taihu, the dominant MC-bound proteins were shown to be similar, but the amount of protein-bound MC varied and correlated with the intracellular MC content. We identified MC-bound proteins by two-dimensional electrophoresis immunoblots and mass spectrometry. The 60 kDa chaperonin GroEL was a prominent MC-bound protein. Three essential glycolytic enzymes and ATP synthase alpha subunit were also major targets of MC-binding, which might contribute to sustained growth in semi-continuous culture. Our results indicate that protein-bound MC may be important for sustaining growth and adaptation ofMicrocystissp.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. weinian710@163.com.|University of Chinese Academy of Sciences, Beijing 100049, China. weinian710@163.com.
authors.forename: Nian
authors.initials: N
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. janicelili@126.com.|University of Chinese Academy of Sciences, Beijing 100049, China. janicelili@126.com.
authors.forename: Lili
authors.initials: L
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. lrsong@ihb.ac.cn.
authors.forename: Lirong
authors.initials: L
authors.lastname: Song
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. gannq@ihb.ac.cn.
authors.forename: Nanqin
authors.initials: N
authors.lastname: Gan
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D002681:China; D005068:Eutrophication; D060106:Lakes / Q000737:chemistry / Q000382:microbiology; D052998:Microcystins / Q000032:analysis / Q000378:metabolism*; D046931:Microcystis / Q000378:metabolism; D011485:Protein Binding; D014873:Water Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D052998:Microcystins; D014873:Water Pollutants
keywords: Lake Taihu; Microcystis aeruginosa; batch culture; microcystin; microcystin-bound protein; semi-continuous culture