EPR STUDIES ON NITRITE REDUCTION TO NITRIC OXIDE IN Pseudomonas BACTERIA

Introduction The reduction of nitrite to nitric oxide (NO) by whole cells of denitrifying bacteria Pseudomonas aeruginosa, P. jluorescens, P. aerufaciens and Acaligenes fecalis was studied by EPR in conjunction with spin trapping technique. Among these bacteria, P. aeruginosa which is ubiquitous in nature and generally innocuous in most environments, is of special clinical interests, since it can cause severe infections in immunosuppressed patients suffering fiorn burn, respiratory disease or cystic fibrosis. We have confirmed that these various Pseudomonas bacteria, under anaerobic condition, are able to reduce nitrite to NO by the enzyme nitrite reductase. It is well known that NO, a very reactive molecule, is capable of giving rise to toxic radical species, thus overproduction of NO contributes to numerous pathological conditions.