黄柏对铜绿假单胞菌毒力因子的影响及机制研究

Effects of aqueous extracts of Phellodendri Chinensis Cortex on virulence factors and its mechanisms in Pseudomonas aeruginosa

目的:观察黄柏对铜绿假单胞菌生物学特性的影响。方法:刚果红降解试验检测弹性蛋白酶活性,氯仿盐酸法测定绿脓菌素分泌量,结晶紫染色法观察生物被膜起始量,平碟法检测菌体集群运动与泳动。结果:在3.12mg/ml、6.25mg/ml和12.5mg/ml时,细菌悬液A600值分别维持在1.752、1.749和1.781,均与对照组A600值1.760无显著差异。此时弹性蛋白酶生成量A495值从0.829降至0.466,均显著低于对照组A495值0.892。绿脓菌素A540值受黄柏水提液干扰,但维持在0.328至0.429,显著低于对照组A495值0.505,且随实验浓度增加而与相应浓度的黄柏水提液对照差值逐渐缩小。生物被膜起始量A560值在3.12 mg/ml时为与对照组无显著差异,分别为0.507和0.505,高于此浓度时,起始量显著降低。选择12.5mg/ml开展菌体运动实验,24 h泳动直径为28.4mm,显著低于对照55.1mm;实验组和对照组24 h和48 h集群运动分别为18.0mm和18.1mm,22.4mm和24.4mm,均未受到显著抑制。结论:黄柏可能含有对密度感应系统产生抑制作用的活性成分,在不影响细菌增殖的条件下便可抑制多种细菌生物学特性,有助于降低细菌耐药性。

Objective： To investigate the effects of Phellodendri chinensis cortex on Pseudomonas aeruginosa virulence,motility and biofilm formation and its mechanism. Methods： Expression of elastase and pyocyanin were assessed quantitatively by using elastin Congo red and ultraviolet spectrophotometry at different concentrations of TCMs. The biofilm formation was detected by Crystal violet staining under the same cultivation condition. Swarm and swim motility assays were undertaken in petri dishes. Results： At the relatively low experimental concentrations of cortex below 12. 5mg / ml,the virulence expressions,including elastase,pyocyanin and biofilm formation were significantly inhibited at varying degrees in contrast to the no significance in bacterial proliferation. Swimming motility at the selected concentration of 12. 5mg / ml was markedly restrained by aqueous extract of cortex whereas swarming motility were not decreased. Conclusion： There may be several inhibitory agents in cortex,suggestng an inhibitory effect on Quorum-sensing system related virulent agents,whereas bacterial growth were not significantly influenced.