Regulation of swimming motility by H-NS in Vibrio parahaemolyticus / 军事医学

Objective To investigate the regulation of swimming motility by H-NS in Vibrio parahaemolyticus(VP). Methods VP was inoculated into the semi-solid swimming agar plate containing 1% Oxoid tryptone, 2% NaCl, 0.5%Difco Noble Agar, and 0.1% arabinose followed by incubation at 37℃ for 4.5 h before the diameters of bacterial lawns were measured.Total RNAs were extracted from the wild-type (WT) strains and the hns null mutant (Δhns), and the quantitative real-time( RT)-PCR( qRT-PCR) was carried out to calculate the transcriptional variation of flaA between WT andΔhns strains.The entire promoter DNA region of flaA was amplified and cloned into the lacZ fusion vector pHRP309 containing a promoterless lacZ gene. The recombinant lacZ reporter plasmid was transformed into WT and Δhns, respectively, to measure the β-galactosidase activities in cellular extracts using the β-galactosidase enzyme assay system. Results and Conclusion The phenotype results showed that swimming motility of VP was enhanced by H-NS.The qRT-PCR and LacZ fusion results indicated that the transcription of flaA was positively regulated by H-NS.Collectively, H-NS promotes the swimming motility of VP, at least partly, by activating the transcription of flaA.

Effect of salinity and temperature on motility of Vibrio parahaemolyticus / 军事医学

Objective To investigate the effect of salinity and temperature on motility of Vibrio parahaemolyticus. Methods V.parahaemolyticus was inoculated on swarming or swimming agar plates containing different amounts of salinity (0.5%, 1.0%, 2.0%, and 4.0% NaCl, respectively), followed by incubation at 26 or 37℃, before the diameters of bacterial lawns were measured .Results and Conclusion The swarming motility was not affected by salinity , while the swimming motility was positively correlated with salinity .Maximum swimming occurred in 2.0% NaCl, and displayed a slight decline in salinity of 4.0%.Both swimming and swarming were affected by temperature , and the motility was signifi-cantly enhanced in 37℃vs 26℃.These results indicate that both salinity and temperature can modulate the motility of V. parahaemolyticus.