PDF(Pubmed)
Abstract：
Bacterial quorum sensing (QS) plays a crucial role in chemical communication between bacteria involving autoinducers and receptors and controls the production of virulence factors in bacteria. Therefore, reducing the concentration of signaling molecules in QS is an effective strategy for mitigating the virulence of pathogenic bacteria. In this study, we demonstrated that carvacrol at 15.625 μg/mL (1/4 MIC), a natural compound found in plants, exhibits potent inhibitory activity against QS in Chromobacterium violaceum, as evidenced by a significant reduction (62.46%) in violacein production. Based on its impressive performance, carvacrol was employed as a natural QS inhibitor to suppress the pathogenicity of Aeromonas hydrophila NJ-35. This study revealed a significant reduction (36.01%) in the concentration of N-acyl-homoserine lactones (AHLs), a QS signal molecular secreted by A. hydrophila NJ-35, after 1/4 MIC carvacrol treatment. Moreover, carvacrol was found to down-regulate the expression of ahyR/I, two key genes in the QS system, which further inhibited the QS system of A. hydrophila NJ-35. Finally, based on the above results and molecular docking, we proposed that carvacrol alleviate the pathogenicity of A. hydrophila NJ-35 through QS inhibition. These results suggest that carvacrol could serve as a potential strategy for reducing the virulence of pathogenic bacteria and minimizing the reliance on antibiotics in aquaculture.
摘要：
细菌群体感应（QS）在涉及自诱导物和受体的细菌之间的化学通讯中起着至关重要的作用，并控制细菌中毒力因子的产生。因此,降低QS中信号分子的浓度是减轻病原菌毒力的有效策略。在这项研究中,我们证明香芹酚的浓度为15.625μg/mL（1/4MIC），一种在植物中发现的天然化合物，对紫罗兰色杆菌中的QS表现出有效的抑制活性，紫罗兰素产量显着下降（62.46％）。基于其令人印象深刻的表现，香芹酚被用作天然的QS抑制剂，以抑制嗜水气单胞菌NJ-35的致病性。这项研究表明，N-酰基高丝氨酸内酯（AHL）的浓度显着降低（36.01％），在1/4MIC香芹酚处理后,由嗜水气单胞菌NJ-35分泌的QS信号分子。此外，发现香芹酚下调AhyR/I的表达，QS系统中的两个关键基因，进一步抑制嗜水菌NJ-35的QS系统。最后,基于上述结果和分子对接，我们提出香芹酚通过QS抑制减轻嗜水气单胞菌NJ-35的致病性。这些结果表明，香芹酚可以作为降低病原菌毒力和减少水产养殖对抗生素依赖的潜在策略。
