RÉSUMÉ
Objective:To explore the function of the cya gene and the preliminary mechanism of attenuated strain.Methods:The biological characteristics of cya mutant in acid and alkali resistant,salt resistance,motility,biofilm components,poisonous to the cells of epithelial cell adhesion,invasion were analysis.Results:The mobility capabilities,acid and alkali resistance and salt tolerance of cya mutant were significantly lower than the parent strain;the composition testing revealed that the cya mutant did not produce cellulose,curli and biofilm;at the same time the adhesion and invasion to epithelial cells of cya mutant had a prominent depression,and the toxicity to HeLa cells was weaker than the parent strain.Conclusion:The function of cya gene is closely related to athletic ability, penetration of cell membrane, the formation biofilm and virulence.It will provide a theory reference to the functional research of Salmonella typhimurium cya gene and the mechanism of attenuated strain.This will contribute to the development of oral vaccine using attenuated Salmonella typhimurium as vector.