Mechanism of the synergistic toxicity of malononitrile and p-nitrobenzaldehyde with Photobacterium phosphoreum

In this study the mechanism of synergistic toxicity between malononitrile and p-nitrobenzaidehyde was revealed by examining their toxicodynamic and toxicokinetic interactions. The investigation of the toxicodynamic interactions focused on the interactions among malononitrile, p-nitrobenzaldehyde, and luciferase, and found that malononitrile does not induce luciferase to bind p-nitrobenzaidehyde. This result suggested that the synergistic toxicity does not arise from toxicodynamic interactions. Further research on toxicokinetic interactions compared the amounts of p-nitrobenzaidehyde being transported from the water phase to the biotic phase in two circumstances-in the presence of malononitrile and in its absence. The results of this research indicated that in the presence of malononitrile, more p-nitrobenzaldehyde is transported, and it is the increased amount of p-nitrobenzaidehyde that leads to the synergistic toxicity of malononitrile and p-nitrobenzaldehyde.