The Antimicrobial Effect And Mechanism Of Lactoferrin Against Pseudomonas Aeruginosa

Partâ… The effect of lactoferrin and iron on the viability andexpression of virulence factors in Pseudomonas aeruginosaObjective To study the bactericidal activity of lactoferrin against Pseudomonasaeruginosa,and its effect on the expression of virulence factors and biofilm formation,atthe same time to explore the influence of iron on its activity.Methods Lactoferrin solution,FeC13 solution and lactoferrin plus FeC13 solution werediluted into a refolding solvent and added into the culture medium of Pseudomonasaeruginosa for evaluating the bactericidal activity respectively;pyocyanine quantificationassay was performed by extraction with chloroform and hydrochloric acid orderly;theelastase activity was detected by using Elastin Congo Red;biofilm quantification assay wasperformed by staining with crystal violet and spectrophotometer assay;biofilm morphologywas viewed by optical microscopy after being stained with crystal violet.Results Lactoferrin have shown the bactericidal activity against Pseudomonasaeruginosa,and inhibited pyocyanine production,elastase activity and biofilm formation,and these effects were positively correlated with their concentrations.FeC13 promoted thegrowth of Pseudomonas aeruginosa,and increased pyocyanine production and elastaseactivity and biofilm formation.These effects of lactoferrin were down-regulated byiron-binding.Conclusions Lactoferrin has bactericidal activity against Pseudomonas aeruginosa,caninhibit the expression of virulence factors.The effects of lactoferrin are correlated with itsiron-binding ability in part. Partâ…¡The effect of iron chelators on the viability and expression ofvirulence factors in Pseudomonas aeruginosaObjective To study the bactericidal activity of 8-hydroxyquinoline(HQ)anddesferoxamine(DFO)against Pseudomonas aeruginosa,and their effects on the expressionof virulence factors and biofilm formation.Methods The solutions of 8-hydroxyquinoline,desferoxamine and one of them plusFeC13 were diluted into a refolding solvent and added into the culture medium ofPseudomonas aeruginosa for evaluating the bactericidal activity respectively;pyocyaninequantification assay was performed by extraction with chloroform and hydrochloric acidorderly;the elastase activity was detected by using Elastin Congo Red;biofilmquantification assay was performed by staining with crystal violet and spectrophotometerassay;biofilm morphology was viewed by optical microscopy after being stained withcrystal violet.Results HQ and DFO have shown the inhibition of bacterial growth,pyocyaninesynthesis,elastase activity and biofilm formation.However,iron-Saturated HQ has shownthe greater inhibition of bacterial growth,pyocyanine synthesis,elastase activity andbiofilm formation than apo-HQ,and iron-Saturated DFO has not shown the inhibition.Conclusions The effects of iron chelators on Pseudomonas aeruginosa are correlatedwith stability-constants for iron,and iron-Saturated HQ has greater inhibition of bacterialgrowth,pyocyanine synthesis,elastase activity and biofilm formation than apo-chelators. Partâ…¢The effect of LF-derived peptides and LFchimera on theviability and expression of virulence factors in pseudomonasaeruginosaObjective To study the bactericidal activity of LF-derived peptides and LFchimeraagainst Pseudomonas aeruginosa,and their effects on the expression of virulence factorsand biofilm formation.Methods The solutions of LFcin,LFampin,LFchimera and LFcin plus LFampin werediluted into a refolding solvent and added into the culture medium of Pseudomonasaeruginosa for evaluating the bactericidal activity respectively;pyocyanine quantificationassay was performed by extraction with chloroform and hydrochloric acid orderly;theelastase activity was detected by using Elastin Congo Red;biofilm quantification assay wasperformed by staining with crystal violet and spectrophotometer assay;biofilm morphologywas viewed by optical microscopy after being stained with crystal violet.Results LFcin,LFampin,LFchimera have shown the bactericidal activity againstPseudomonas aeruginosa,and inhibited pyocyanine production,elastase activity andbiofilm formation,and these effects were positively correlated with their concentrations.The effects of LFchimera are greater significantly than LFcin,LFampin and their mixtures.Conclusions Lactoferrin-derived peptides and lactoferrin peptides chimera,especiallyLFchimera have the great antibacterial activity against Pseudomonas aeruginosa,arepromissory new compounds for a treatment for P..aeruginosa infections.