title: iTRAQ-based quantitative proteomic analysis of Microcystis aeruginosa exposed to spiramycin at different nutrient levels.
abstract: Research on the combined effects of antibiotic contaminants and environmental factors in cyanobacteria is still limited. This study focused on the action and its mechanism of spiramycin combined with changes in nitrogen and phosphorus level in Microcystis aeruginosa at environmentally relevant concentrations. Though photosynthetic activity was stimulated by spiramycin at a high nutrient level, no significant correlation (p>0.05) was found between photosynthesis-related proteins and growth-related proteins, and the growth rate was inhibited by 200ngL-1of spiramycin. At low nitrogen and low phosphorus levels, up-regulated photosynthesis-related proteins were closely correlated with (p<0.05) stress response-related, transcription-related and cell division-related proteins, which consequently led to stimulated growth of M. aeruginosa under spiramycin exposure. Spiramycin exposure also regulated the production of microcystins (MCs) and the expression of two microcystin synthetases (mcyB and mcyC). The spiramycin-induced protein secretion process and the up-regulation of ATP binding cassette transporters might contribute to the increased MC release. Enolase, superoxide dismutase, protein GrpE, DNA-directed RNA polymerase subunit alpha and serine protease were candidate target proteins of spiramycin in M. aeruginosa under different nutrient conditions. Coexisting spiramycin mitigated the threat of cyanobacteria to aquatic environments at a high nutrient level but aggravated cyanobacterial bloom at a low nitrogen level.
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, PR China.
authors.forename: Shi
authors.initials: S
authors.lastname: Chen
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, PR China. Electronic address: liuying2010@sdu.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, PR China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, PR China.
authors.forename: Baoyu
authors.initials: B
authors.lastname: Gao
mesh_terms: D016000:Cluster Analysis; D007553:Isotope Labeling / Q000379:methods*; D052998:Microcystins / Q000096:biosynthesis; D046931:Microcystis / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D060066:Protein Interaction Maps; D040901:Proteomics / Q000379:methods*; D015572:Spiramycin / Q000032:analysis / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D052998:Microcystins; D014874:Water Pollutants, Chemical; C078588:microcystin; D015572:Spiramycin
keywords: Antibiotic contamination; Cyanobacterial bloom; Ecotoxicology; Nitrogen; Phosphorus; Proteome