title: Comparative proteome analysis of two Streptococcus agalactiae strains from cultured tilapia with different virulence.
abstract: Streptococcus agalactiae is a major piscine pathogen, which causes significant morbidity and mortality among numerous fish species, and results in huge economic losses to aquaculture. Many S. agalactiae strains showing different virulence characteristics have been isolated from infected tilapia in different geographical regions throughout South China in the recent years, including natural attenuated S. agalactiae strain TFJ0901 and virulent S. agalactiae strain THN0901. In the present study, survival of tilapia challenged with S. agalactiae strain TFJ0901 and THN0901 (10(7)CFU/fish) were 93.3% and 13.3%, respectively. Moreover, there are severe lesions of the examined tissues in tilapia infected with strain THN0901, but no significant histopathological changes were observed in tilapia infected with the strain TFJ0901. In order to elucidate the factors responsible for the invasive potential of S. agalactiae between two strains TFJ0901 and THN0901, a comparative proteome analysis was applied to identify the different protein expression profiles between the two strains. 506 and 508 cellular protein spots of S. agalactiae TFJ0901 and THN0901 were separated by two dimensional electrophoresis, respectively. And 34 strain-specific spots, corresponding to 27 proteins, were identified successfully by MALDI-TOF mass spectrometry. Among them, 23 proteins presented exclusively in S. agalactiae TFJ0901 or THN0901, and the other 4 proteins presented in different isomeric forms between TFJ0901 and THN0901. Most of the strain-specific proteins were just involved in metabolic pathways, while 7 of them were presumed to be responsible for the virulence differences of S. agalactiae strain TFJ0901 and THN0901, including molecular chaperone DnaJ, dihydrolipoamide dehydrogenase, thioredoxin, manganese-dependent inorganic pyrophosphatase, elongation factor Tu, bleomycin resistance protein and cell division protein DivIVA. These virulence-associated proteins may contribute to identify new diagnostic markers and help to understand the pathogenesis of S. agalactiae.
authors.affiliation: Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, 135 Xingang West Street, Haizhu District, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, 135 Xingang West Street, Haizhu District, Guangzhou 510275, Guangdong Province, PR China; Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, Guangdong Province, PR China.
authors.forename: You-Lu
authors.initials: YL
authors.lastname: Su
authors.affiliation: Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, 135 Xingang West Street, Haizhu District, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: Yong-Zhan
authors.initials: YZ
authors.lastname: Mai
authors.affiliation: Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, 135 Xingang West Street, Haizhu District, Guangzhou 510275, Guangdong Province, PR China.
authors.forename: Yan-Wei
authors.initials: YW
authors.lastname: Li
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou, Guangdong Province, PR China.
authors.forename: Ze-Quan
authors.initials: ZQ
authors.lastname: Mo
authors.affiliation: Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, 135 Xingang West Street, Haizhu District, Guangzhou 510275, Guangdong Province, PR China. Electronic address: lianxing@mail.sysu.edu.cn.
authors.forename: An-Xing
authors.initials: AX
authors.lastname: Li
mesh_terms: D000818:Animals; D017756:Aquaculture; D002681:China; D005393:Fish Diseases / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D015964:Gene Expression Regulation, Bacterial; D020543:Proteome / Q000235:genetics*; D013290:Streptococcal Infections / Q000382:microbiology / Q000401:mortality / Q000473:pathology / Q000662:veterinary*; D013292:Streptococcus agalactiae / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D017210:Tilapia / Q000382:microbiology; D014774:Virulence / Q000235:genetics*
chemical_list: D020543:Proteome
keywords: Comparative proteome; Streptococcus agalactiae; Tilapia; Virulence