连翘提取物对嗜水气单胞菌群体感应系统的影响

Effect of Forsythia suspensa extract on quorum sensing system of Aeromonas hydrophila

摘要:

[背景] 传统抑菌剂的大量使用导致细菌产生多重耐药性与抗性，而基于细菌群体感应靶点调控的新型抑菌剂可缓解细菌耐药性与抗性，是未来抑菌剂的发展方向之一。[目的] 研究连翘（Forsythia suspensa）提取物对嗜水气单胞菌（Aeromonas hydrophila）群体感应系统的影响及可能的作用机制，为新型抑菌剂的开发提供理论依据。[方法] 以紫色杆菌（Chromobacterium violaceum） CV026为报告菌株，以嗜水气单胞菌为供试菌株，采用倍比稀释法测定连翘提取物对2种菌的最小抑菌浓度（minimal inhibitory concentration，MIC），通过微量法测定提取物对嗜水气单胞菌生长、群集运动及蛋白酶活性的影响，利用高效液相色谱串联质谱法分析提取物中的主要成分，采用分子对接模拟探究提取物对嗜水气单胞菌群体感应系统的作用机制。[结果] 连翘提取物对紫色杆菌CV026和嗜水气单胞菌的MIC均为16.00 mg/mL。在亚抑菌浓度下，连翘提取物处理显著抑制了CV026紫色菌素的产生，最大抑制率高达56.30%。经8.00 mg/mL连翘提取物处理后，嗜水气单胞菌的群集运动迁移能力（85.70%）及蛋白酶活性（35.40%）均受到抑制，而且呈现出浓度依赖性。连翘提取物的主要成分为连翘苷、连翘酯苷、槲皮素、咖啡酸等，分子对接结果表明，槲皮素、咖啡酸等成分可与细菌群体感应LasR受体蛋白竞争性结合，从而抑制嗜水气单胞菌的群体感应系统。[结论] 连翘提取物可作为细菌群体感应抑制剂或新型抑菌剂应用于水产养殖或生物防治等领域。

Abstract:

[Background] The new antimicrobial agents based on the quorum sensing system control was rapidly developed due to the multiple drug resistance caused by traditional antimicrobial agents. [Objective] To study the effect of Forsythia suspensa extract (FSE) on quorum sensing system in Aeromonas hydrophila and provide useful information for bacteria control. [Methods] The minimal inhibitory concentration (MIC) of FSE against Chromobacterium violaceum CV026 and A. hydrophila was determined by multiple dilution method, and the effects of FSE on the growth, swarming motility and protease activity of A. hydrophila were determined by micro-method. The primary components of the extracts were analyzed by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The possible inhibiting mechanism of FSE on the quorum sensing system of A. hydrophila was explored by molecular docking. [Results] The MICs of FSE against C. violaceum 026 and A. hydrophila were both 16.00 mg/mL. Under sub-MIC concentration, and the production of violacein was significantly inhibited by the FSE, with the maximum inhibition rate of 56.30%. The swarming mobility and protease activity of A. hydrophila was reduced by 85.70% and 35.40% with 8.00 mg/mL FSE treatment, respectively. The major components of the FSE included forsythia, forsythioside, caffeic acid and chlorogenic acid, etc. The molecular docking results indicated that caffeic acid and chlorogenic acid could competitively bind with LasR receptor protein to inhibit the quorum sensing system of A. hydrophila. [Conclusion] FSE could be used as a potential quorum sensing inhibitor in the aquaculture and biological control area.