OxyFile #161

Superoxide Dismutase and Oxygen Toxicity Defenses in the Genus 

Infection and Immunity, Feb. 1986, p. 631-641

Frederick S. Archibald and Minh-Ngoc Duong

Department of Microbiology and Immunology, 
McGill University 
Montreal, Quebec, 
Canada, H3A 2B4


Among aerotolerant cells, Neisseria gonorrhoeae is very unusual 
because despite its obligately aerobic lifestyle and frequent 
isolation from purulent exudates containing polymorphonuclear 
leukocytes vigorously evolving O2 and H2O2, it contains no superoxide 
dismutase (SOD). Strains (14) of N. gonorrhoeae were compared with 
each other and with strains of Neisseria meningitidis, Neisseria 
mucosa, and Neisseria subflava under identical growth conditions for 
their contents of the oxy-protective enzymes catalase, peroxidase, and 
SOD, as well as respiratory chain proteins and activity. The absence 
of SOD from N. gonorrhoeae strains was demonstrated under a variety of 
oxygen-stress conditions. The neisserial species showed very different 
SOD, catalase, and peroxidase profiles. These profiles correlated well 
with the tolerance of the species to various intra- and extracellular 
oxygen insults. The high tolerance of N. gonorrhoeae for extracellular 
O2 and H2O2 appeared to be due to very high constitutive levels of 
peroxidase and catalase activity combined with a cell envelope 
impervious to O2. Nevertheless, N. gonorrhoeae 19424 was much more 
sensitive to an intracellular flux of O2 than were the other (SOD-
containing) neisserial species. The responses of N. gonorrhoeae and N. 
meningitidis respiratory end oxy-protective enzymes to growth under 
high and low oxygen tensions were followed, and a novel response, the 
apparent repression of the respiratory chain intermediates, 
respiration, and SOD, peroxidase and catalase activity, was observed. 
The gonococcal catalase was partially purified and characterized. The 
results suggest that the very active terminal oxidase, low pO2 natural 
habitat, O2 -stable catalase, and possibly the high glutathione 
content of the organism explain its aerobic survival in the absence of 

Received 5 August 1985/Accepted 24 October 1985