Bisphenol A (BPA) poses multiple risks to human health, and it has become a critical environmental pollution issue. The advantage of bacterial degradation of BPA has become more prominent, and enhancement methods have become increasingly diverse. Using quorum sensing to regulate functional bacteria and genes to enhance the bacterial degradation efficiency of BPA serves as a highly promising new approach. This study investigated the effect of adding exogenous N-hexanoyl-L-homoserine lactone (C6-HSL) on the degradation of BPA by Pseudomonas asiatica P1 (strain P1) and analyzed the regulatory mechanism of the signaling molecules. The results showed that exogenous homoserine lactone signaling molecules (AHLs) could enhance the BPA degradation efficiency of strain P1, with 10 μM C6-HSL demonstrating the most significant enhancement, increasing the degradation rate by 12.4 % compared with the control group and producing products such as benzoic acid and succinic acid. In terms of the regulatory mechanism, C6-HSL preferentially induced a 5.18-fold upregulation in the expression of the AHL receptor-encoding gene LasR. Subsequently, LasR regulates the upregulation of hub genes such as bvgS and aruS , ultimately achieving an upregulation of BPA degradation genes through hierarchical regulation. This led to an enhancement in the initial degradation step of BPA and the activation of the benzoic acid degradation pathway. This study analyzed the potential of C6-HSL to enhance microbial BPA degradation and, for the first time, clarified the mechanism by which C6-HSL enhanced bacterial BPA degradation efficiency through hierarchical regulation.
The development of antibiotic-resistant microorganisms is a major global health concern. Recently, there has been an increasing interest in antimicrobial peptides as a therapeutic option. This study aimed to evaluate the triple-action (broad-spectrum antibacterial, anti-biofilm, and anti-quorum sensing activities) of melittin, a membrane-active peptide present in bee venom. The minimum inhibitory concentration and minimum bactericidal concentration of the melittin were determined using the microdilution method and agar plate counting. Growth curve analysis revealed that melittin showed a concentration-dependent antibacterial activity. Scanning electron microscope analysis revealed that melittin treatment altered the morphology. Confocal laser scanning microscope revealed that melittin increased the membrane permeability and intracellular ROS generation in bacteria, all of which contribute to bacterial cell death. In addition, the crystal violet (CV) assay was used to test the anti-biofilm activity. The CV assay demonstrated that melittin inhibited biofilm formation and eradicated mature biofilms. Biofilm formation mediated by quorum sensing (QS) plays a major role in this regard, so molecular docking and molecular dynamics analysis confirmed that melittin interacts with LasR receptors through hydrogen bonds, and further evaluates the anti-QS activity of melittin through the production of virulence factors (pyocyanin, elastase, and rhamnolipid), exopolysaccharides secretion, and bacterial motility, that may be the key to inhibiting the biofilm formation mechanism. The present findings highlight the promising role of melittin as a broad-spectrum antibacterial, anti-biofilm agent, and potential QS inhibitor, providing a new perspective and theoretical basis for the development of alternative antibiotics.Keywords:antimicrobial peptides;melittin;antibacterial;anti-biofilm;anti-quorum sensing
危险品化学品经营许可证（带存储）