Monohalogenated maleimides as potential agents for the inhibition of Pseudomonas aeruginosa biofilm.

New monohalogenated maleimide derivatives (with bromine, chlorine or iodine) were synthesized to test the effect of halogen atoms in inhibiting the formation of Pseudomonas aeruginosa biofilm. The evaluation of their biological activities clearly defines a structure-activity relationship. In this study, the bactericidal action of the three compounds was observed at the concentration range 0.

On-line high-performance liquid chromatography-mass spectrometric detection and quantification of N-acylhomoserine lactones, quorum sensing signal molecules, in the presence of biological matrices.

A protocol using reversed-phase liquid chromatography coupled with positive-ion electrospray ionization and ion trap mass spectrometry is described for the identification and quantification of N-acylhomoserine lactones (HSLs) in crude cell-free supernatants of bacterial cultures. The HSLs are produced by gram-negative bacteria and act as intercellular signals inducing density-dependent gene expression. Compared with the multi-step procedures previously reported, which included chemical extraction, purification and the use of Escherichia coli HSL biosensors, this on-line LC-MS-MS method is fast and detects 11 HSLs.