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 -nitrobenzaldehyde 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 -nitrobenzaldehyde. This result suggested that the synergistic toxicity does not arise from toxicodynamic interactions. Further research on toxicokinetic interactions compared the amounts of p -nitrobenzaldehyde 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 -nitrobenzaldehyde that leads to the synergistic toxicity of malononitrile and p -nitrobenzaldehyde.