LuxO controls extracellular protease, haemolytic activities and siderophore production in fish pathogen Vibrio alginolyticus.
OBJECTIVE
To characterize the luxO gene in fish pathogen Vibrio alginolyticus MVP01 and investigate its roles in regulation of extracellular products (ECP) and siderophore production.


RESULTS
The luxO gene was cloned from V. alginolyticus MVP01. Genetic analysis revealed that it encoded a protein with high similarity to other LuxO homologues. The luxO in-frame deletion mutant and rpoN null mutant were constructed with suicide plasmids. We demonstrated that sole deletion in LuxO increased the secretion of extracellular protease and haemolytic products, but decreased siderophore production for V. alginolyticus MVP01. Mutants with null rpoN displayed significantly enhanced protease level and siderophore production while notable reduction in haemolytic activities of ECP.


CONCLUSIONS
Vibrio alginolyticus harbours functional luxO gene that regulates the secretion of extracellular protease and haemolytic materials as well as siderophore production in either sigma(54) dependent or independent manners.


CONCLUSIONS
The current study demonstrated that V. alginolyticus MVP01 produces extracellular protease and haemolytic activity material as well as siderophore, which may be characteristics of the virulence of the strain. Revelations that secretion of these products is under the regulation of LuxO and sigma(54) as well as the potential quorum sensing systems in V. alginolyticus MVP01 will expedite the understanding of vibriosis pathogenesis.
Wang
Q
Q
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China.
Liu
Q
Q
Ma
Y
Y
Rui
H
H
Zhang
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D005110:Extracellular Space / Q000378:metabolism; D005393:Fish Diseases / Q000382:microbiology; D005399:Fishes / Q000469:parasitology*; D005516:Food Microbiology; D006461:Hemolysis; D008969:Molecular Sequence Data; D009154:Mutation; D010447:Peptide Hydrolases / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017262:Siderophores / Q000032:analysis / Q000096:biosynthesis*; D014157:Transcription Factors / Q000235:genetics; D014733:Vibrio / Q000235:genetics; D014735:Vibrio Infections / Q000382:microbiology; D044149:Vibrio alginolyticus / Q000235:genetics* / Q000378:metabolism; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; C088907:LuxO protein, Vibrio harveyi; D012097:Repressor Proteins; D017262:Siderophores; D014157:Transcription Factors; D010447:Peptide Hydrolases