Time-dependent effects of [apyr]BF4 and key contributors to their mixture stimulation on Vibrio qinghaiensis sp.-Q67 at apical and biochemical levels.

Earlier reports studied the time-dependent effects of imidazolium-based ionic liquids ([amim]X) in the aspect of biochemical explanation and that of key contributor in mixture effects. Presently, the effects of N -alkylpyridinium-based ILs ([apyr]BF 4 ) were studied combining the above two aspects, i.e. , the time-dependent effects of [bpyr]BF 4 , [hpyr]BF 4 and [opyr]BF 4 on luminescence and biochemical indicators in Vibrio qinghaiensis sp.-Q67, and those of the mixtures. In individual results, the inhibition on luminescence increased over concentrations and the side chain length, showing concentration- and side chain-dependence. Moreover, the inhibition of [apyr]BF 4 decreased from 0.25 to 24 h, showing a time-dependence. Notably, [hpyr]BF 4 stimulated the luminescence at 24 h. The biochemical effects, including inhibition and stimulation, were well correlated to those on luminescence. In mixture results, the inhibition on luminescence was lower than the predicted effects by concentration addition model which was based on individual results. Moreover, the mixture stimulation on luminescence was significantly higher than individual ones, and the mixture stimulation on biochemical indicators was even greater than that on luminescence. In mixture effects, [bpyr]BF 4 was the positive contributor, and [hpyr]BF 4 was the negative contributor. Similarities and differences between [amim]X and [apyr]BF 4 indicated underlying mechanisms of the commonly observed hormetic effects of ionic liquids. [ABSTRACT FROM AUTHOR]