Open AccessRegulation system for protease production in Vibrio vulnificus
Author(s) -
Kawase Tomoka,
Miyoshi Shinichi,
Sultan Zafar,
Shinoda Sumio
Publication year - 2004
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/j.femsle.2004.09.023
Subject(s) - vibrio vulnificus , quorum sensing , microbiology and biotechnology , proteases , homoserine , autoinducer , protease , biology , biochemistry , gene expression , siderophore , bacteria , chemistry , gene , virulence , enzyme , genetics
Vibrio vulnificus is a causative agent of serious food‐borne diseases in humans related to consumption of raw seafoods. This human pathogen secretes a metalloprotease (VVP) that evokes enhancement of the vascular permeability and disruption of the capillaries. Production of microbial proteases is generally induced at early stationary phase of its growth. This cell density dependent regulation of VVP production in V. vulnificus known to be the quorum‐sensing. When V. vulnificus was cultivated in Luria–Bertani (LB) medium, accumulation of the autoinducer, the signal molecule operating the quorum‐sensing system, was detected. Moreover, expression of the vvp gene encoding VVP was found to be closely related with expression of the luxS gene that encode the synthase of the autoinducer precursor ( luxS ). These findings may indicate VVP production is controlled by the quorum‐sensing system in LB medium. Futhermore, this system functioned more effectively at 26 °C than at 37 °C. When incubated at 37 °C in human serum supplemented with ferric chloride, production of VVP and expression of vvp increased in proportion to the concentration of ferric ion; whereas, expression of luxS was not increased. This suggests that VVP production in human serum containing ferric ion may be regulated mainly by the system other than the quorum‐sensing system.