Abstract:

AcrA is a membrane fusion protein in Gram-negative bacteria,and scientists mainly study the regulation of AcrA protein in the process of drug efflux and other membrane transport in bacteria. To elucidate the effects of acrA deficient strain ΔacrA in the bacteria on physiological functions such as hemolytic,toxicological,stress and antibiotic sensitivity,acrA（AHA_2911）deleted strain was constructed in A. hydrophila using traceless based homologous recombination technology. The physiological phenotypes,such as hemolytic,extracellular protease activity,antibiotics susceptibility,high temperature stress,growth trends,and biofilm formation ability for both wild strain and ΔacrA were measured. The results showed that the hemolytic and extracellular protease activities in the ΔacrA were not affected,while the acrA deletion increased the antibiotics sensitivity of the ΔacrA to kanamycin,erythromycin,balofloxacin and acriflavinium chloride,and significantly improved the biofilm formation. But,the growth trend of ∆acrA and its biofilm formation ability at 42^oC were significantly lower than wild strain. The above studies proved that acrA has a certain function in drug efflux pumps and suggested that it may play an important role in the high temperature tolerance and biofilm formation.

Key words: acrA, Aeromonas hydrophila, homologous recombination, physiological phenotype, biofilm, high temperature