Characterization of acylated homoserine lactone derivatives and their influence on biofilms of Acidithiobacillus ferrooxidans BY-3 under arsenic stress

Quorum sensing is one kind of cell-to-cell signalling system among microorganisms that works in response to their population density via autoinducers exemplified by AHL and oligopeptides. In this study, fourteen AHL derivatives were synthesised by a chemical synthesis method, and two types of AHL derivatives were measured and screened by crystal violet staining assay, which have more obvious inhibitory effects on A. ferrooxidans biofilms under arsenic environment. Their structures were verified through IR and NMR identification. The morphological changes of A. ferrooxidans under the influence of the AHL derivatives were compared. In addition, the effects of AHL derivatives (0.1 µg/mL and 1 µg/mL) on membrane formation of A. ferrooxidans under high concentration of arsenic resistance (1,600 mg/L) were explored. Solid experimental data firstly showed that a portion of logarithmic microorganisms were ruptured under the effect of high arsenic concentration. Secondly, the volume of the cell shrank and the number of extracellular polymeric substances decreased after the addition of the AHL derivatives at high concentrations. Therefore, we found here that two derivatives used at concentrations of 0.1 µg/mL and 1 µg/mL accompanied with high concentration of arsenic can both effectively restrict biofilms formation by A. ferrooxidans .