title: Role of alkaline serine protease, asp, in vibrio alginolyticus virulence and regulation of its expression by luxO-luxR regulatory system.
abstract: The alkaline serine protease asp, which was shown to be a virulence factor of Vibrio alginolyticus as a purified protein, was cloned from V. alginolyticus EPGS, a strain recently isolated from moribund Epinephelus coioides in an outbreak of vibriosis in a mariculture farm of Shenzhen. The asp null mutant was constructed by homologous recombination with suicide plasmid pNQ705-1. Compared with the wild-type strain, the asp null mutant exhibited a significant decrease of total extracellular protease activity, and caused a 15-fold decrease in virulence of V. alginolyticus. In our previous study, the luxO and luxR(val) genes from V. alginolyticus MVP01 were cloned and identified, and the luxO-luxR(val) regulatory couple was shown to regulate various genes expression, suggesting that it played a central role in the quorum sensing system of V. alginolyticus. In this study, the regulation of the asp gene was analyzed by using RT-PCR and quantitative real-time PCR methods; we proved that its transcription was greatly induced at the late large stage of growth and was regulated by luxO-luxR(val) regulatory system.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
authors.forename: Haopeng
authors.initials: H
authors.lastname: Rui
authors.forename: Qin
authors.initials: Q
authors.lastname: Liu
authors.forename: Qiyao
authors.initials: Q
authors.lastname: Wang
authors.forename: Yue
authors.initials: Y
authors.lastname: Ma
authors.forename: Huan
authors.initials: H
authors.lastname: Liu
authors.forename: Cunbin
authors.initials: C
authors.lastname: Shi
authors.forename: Yuanxing
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001492:Bass / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D008969:Molecular Sequence Data; D053038:Quorum Sensing; D012329:RNA, Bacterial / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D012097:Repressor Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014735:Vibrio Infections / Q000382:microbiology; D044149:Vibrio alginolyticus / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012097:Repressor Proteins; D015534:Trans-Activators; D037521:Virulence Factors; C064778:LuxR autoinducer binding proteins; D012697:Serine Endopeptidases