ABSTRACT
Objective: To investigate the mechanism of sodium houttuyfonate (SH) against Pseudomonas aeruginosa (PA) targeting quorum sensing system. Methods: The microdilution method was adopted to determine the minimal inhibitory concentration (MIC) of SH and azithromycin (AZM) for PA; The effects of SH on LasA proteases activity and pyocyanin production were detected by UV spectrophotometry; The semi-quantitative PCR and qRT-PCR were used to detect the expression changes of quorum sensing regulatory genes (lasI, rhlI, lasR, rhlR, phzM, pqsA, pslA, lasA, lasB, and toxA). Results: The MIC of P. aeruginosa for SH and AZM was 512 μg/mL and 64 μg/mL, respectively; SH could significantly inhibit the activity of LasA proteases, and pyocyanin of bacteria; The morphology of P. aeruginosa was observed by agar plates; Furthermore, semi-quantitative PCR and qRT-PCR results indicated that the expression of lasI, rhlI, lasR, lasA, pslA, and phzM was significantly impact by SH. Conclusion: The results of present study suggest that SH possesses anti-quorum sensing properties and plays a role against infection by anti-quorum sensing activity.
ABSTRACT
Ligustrum sinense are commonly used for their anti-inflammatory, anti-rheumatic, diuretic, and hypotensive activities in traditional Chinese medicine. To observe the effects of the combined treatment of a water-soluble extract of Ligustrum sinense (WEL) and gentamicin sulphate (GS) on Pseudomonas aeruginosa PA01, the micro-dilution method was used to determine the minimal inhibitory concentration (MIC) of GS. Formation of a PA01 biofilm was observed under an optical microscope after treatment with different dosages of WEL and combined treatment with GS. The MIC of WEL was 8g l-1, and permanent activity was also observed. The effect of WEL with GS was synergistic. The motility, biomass of biofilms, and production of pyocyanin of P. aeruginosa were strongly suppressed in the presence of WEL. The conclusion can be drawn that combined antibiotics can be used to treat the contamination due to the biofilm formation caused by P. aeruginosa.
ABSTRACT
Pseudomonas aeruginosa is one of the most common causes of nosocomial infection due to its intrinsic resistance to antibiotics. In the host,glutathione(GSH) ,one of the most important intracellular antioxidants,provides protection against high levels of oxidative stress. A decrease in GSH levels in tissues infected with P. aeruginosa has been observed while interactions between pyocyanin and GSH maybe partially attribute to P. aeruginosa infection. In this review,the relationship between GSH and the pathogenicity of P. aeruginosa has been discussed based on the author's own research results and the latest literature.
ABSTRACT
Aim To study IL-8 expression of human airway epithelium-like NCI-H292 cells directly induced by Pyocyanin and its mechanism through protein kinase C(PKC) and nuclear factor-kappa B(NF-??).Methods ELISA methods were performed to test the expression of IL-8 in NCI-H292 cells infected by Pyocyanin.Western blot was employed to examine the expression of NF-?B protein.In addition,NCI-H292 cells were cultured together with PKC inhibitor,calphostin C or NF-?? inhibitor,pyrrolidine dithiocarbamate(PDTC),respectively before Pyocyanin infection,then the expression of IL-8 and NF-?? was assayed using the above methods.Results Pyocyanin was able to induce IL-8 protein secretion in NCI-H292 cells and had marked concentration-dependent relations.Pyocyanin could also significantly promote the activation of NF-?B,which peaked at 60~90 min.PDTC and calphostin C could significantly decrease the activation of NF-?? and the expression of IL-8.Conclutions Pyocyanin can induce IL-8 production.The direct induction of Pyocyanin can promote the activation of NF-?B by PKC signal pathway,then cause the expression and secretion of IL-8.