Antioxidant enzyme activity in bacterial resistance to nicotine toxicity by reactive oxygen species.

We analyzed superoxide dismutase (SOD), catalase (CAT), and ATPase activities in the highly nicotine-degrading strain Pseudomonas sp. HF-1 and two standard strains Escherichia coli and Bacillus subtilis in an attempt to understand antioxidant enzymes in bacteria are produced in response to nicotine, which increases the virulence of the bacteria. Nicotine had different effects on different antioxidant enzymes of different bacteria. SOD plays a more important role in resistance to nicotine stress in E. coli than it does in CAT. Multiple antioxidant enzymes are involved in combating oxidative stress caused by nicotine in Pseudomonas sp. HF-1. The contribution of a particular antioxidant enzyme for protection from nicotine stress varies with the growth phase involved. The inhibition of ATPase in Pseudomonas sp. HF-1 at the stationary phase was enhanced with increasing nicotine concentration, showing a striking dose-response relationship. Nicotine probably affected the metabolism of ATP to some extent. Furthermore, different bacteria possessed distinct SOD isoforms to cope with oxidative stress caused by nicotine.