Influences Of TssJ Gene On Motility And Biofilm Formation Of Vibrio Alginolyticus

Vibrio alginolyticus, distributed in marine around the world, is the serious disease agent of marine animals and human beings. The matural TssJ protein is tethered to the outer membrane by the acylated N-terrminal cysteine residue and protrudes into the periplasm. Besides, it could influenc significantly the toxicity of Enteroaggrerative E.coli. However, there is still no report about the function of tssJ in V. alginolyticus. In this study, tssJ-dependent regulation of motility and biofilm formation in V. alginolyticus, were further investigated.We obtained the deletion mutants strains of tssJ of V. alginolyticus HN08155, which attenuated its virulence to Litopenaeus vannamei. There is to be tried to construct the tssJ complement strain with plasmid pACYC184. But when transferred pACYC184with tssJ gene into AtssJ, it was found a large transposon inserting variable genomic sequences into the plasmid, which resulted in tssJ gene failed to expression in the complement strain. Simultaneously, When transferred pMMB206and pJN105intoâ–³tssJ, the same phenomenon was observed. This result indicated that the transposon system in V. alginolyticus strain HN08155could modify stongly the foreign DNA to protect its genome.In the study, tssJ was proved to be involvement in the regulation of motility and biofilm biogenesis in V. alginolyticus. Flagella staining and molity tests showed that theâ–³tssJ was no flagella and less-motile, which expressed that tssJ had a significant positive regulation in motility. Observation with the scanning electron microscope and the confocal laser scanning microscope, biofilm of WT andâ–³tssJ were constituted by micro-colonies and extracellular products such as polysaccharides. It was tested the amounts of biofilm and exopolysaccharides of WT andâ–³tssJ. The results showed the WT cells produced more biofilm and soluble exopolysaccharides than theâ–³tssJ, but less insoluble exopolysaccharides, which meant tssJ could promote the biofilm of V. alginolyticus HN08155, and change the exopolysaccharides type. Additionally, the amounts of biofilm of WT andâ–³tssJ were investigated in different concentrations of ions. tssJ promoted the biofilm formation of V. alginolyticus with KC1(P>0.05). However, NaCl and CaCl2played no significant role in its biofilm formation. No regular variation tendency was observed while cultured with MgCl2and NaNO3.In summary, it was speculated that tssJ promoted the motility and biofilm formation of V. alginolyticus, which implied that tssJ it was an important virulence gene.