Study Of Sorbic Acid Nanoparticles On The Bacteriostasis Of Constitutive And Inducible Recombinant Luminescent Bacteria With Lux Gene

In this research,we selected inducible recombinant bacteria E.coli DPD2794,E.coli TV1061,and constitutive recombinant strain E.coli Top10-P.luxCDABE,E.coli DH5?-P.luxCDABE to finish the study.The effect of SAN on the growth and luminescence of recombinant luminescent bacteria and of field emission scanning electron microscopy(SEM)were used to evaluate the antibacterial activity of sorbic acid nanoparticles.The conclusions were as below:1.In the optimum luminescence temperature of two recombinant bacteriaE.coli DPD2794 andE.coli TV1061 was 27?and 28?,respectively.The luminescent intensity of both bacteria increased rapidly during the logarithmic phase,and the maximum luminescent intensity was 255(E.coli DPD2794)and 422(E.coli TV1061).The maximum luminous intensity of E.coli DPD2794 and E.coli TV106 was 27?and 28?,their maximum resistance to light temperature was33? and 32?,respectively.The OD value and luminescent intensity of E.coli TV1061 reached the maximum when the pH was 6.The MIC of sorbic acid nanoparticles on the inducible recombinant bacteria E.coli DPD2794 and E.coli TV1061 were 60 ?g/mL and 64 ?g/mL,respectively.The MIC of sorbic acid nanoparticles on the constitutive recombinant bacteria E.coliTop10-P.luxCDABE and E.coli DH5?-P.luxCDABE were 52 ?g/mL and 40 ?g/mL,respectively.2.With the increase of SAN concentration,the maximum luminous intensity of two constitutive recombinant bacteriawas significantly decreased(P<0.05).The growth and luminous intensity of the two inducible recombinant bacteria were completely inhibited by the respective MIC concentration of SAN treatment.The responses of DPD2794 bacterial cells are mainly restricted to that of genotoxicity.SAN could inhibited its luminescence in high concentration,while it could promote the cell luminescence in low concentration(?3.75?g/mL).The responses of TV1061 bacterial cells are mainly restricted to that of metabolic changes.SAN could inhibit the cell luminescence of TV1061.It indicated SAN could play an inhibitory effect on bacterial cells by DNA damage.3.Scanning electron microscopy(SEM)images of inducible and constitutive recombinant bacteria treated by SAN showed that the cell membrane was destroyed,the cells ruptured,the intracellular material dissoluted,and the partially damaged cells were attached to SAN.According to the results of SEM images and the mechanism of chitosan nanoparticles and sorbic acid,the mechanism of SAN might be deduced by using the mucosal adhesion of chitosan nanoparticles to combine sorbic acid nanoparticles with membrane protein,The structure of the membrane protein changed the physiological structure of the cell.Sorbic acid,could destroy the cell structure and inhibit the growth of recombinant luminescent bacteria.