Inhibition of biofilm formation by chemical uncoupler, 3, 3″ 4″ 5-tetrachlorosalicylanilide (TCS): From the perspective of quorum sensing and biofilm related genes

Biological anti-biofouling strategy based on chemical uncoupler is considered as a potential alternative in membrane filtration systems. However, the inhibitory mechanism of uncoupler on biofilm development remains to be uncovered. To bridge the knowledge gap, this study investigated the inhibitory effectiveness of TCS on a gram-positive bacterial biofilm formation and analyzed the genes expression associated with quorum sensing (QS) system and biofilm formation via real-time quantitative polymerase chain reaction (RT-qPCR). TCS was observed to inhibit the biofilm formation of B. subtilis as low as 100 μg/L. The expression of genes associated with ComX QS system were not changed. However, the sinR and abrB genes which were modulated by CSF QS system, were upregulated by 100 μg/L TCS. The SinR protein negative regulated genes (epsE, tasA and yqxM) involved in extracellular matrix production were repressed, corroborating the reduction of extracellular matrix was the main cause of biofilm inhibition by TCS.