Transcriptional analysis of the rubrerythrin and superoxide dismutase genes of Clostridium perfringens

We cloned and sequenced a 2.7-kb fragment of chromosomal DNA from Clostridi um perfringens containing the superoxide dismutase-encoding gene, sad. Prev iously, rubrerythrin from C. perfringens had been isolated and its gene (rb r) had been cloned (Y. Lehmann, L. Meile, and M. Teuber, J. Bacteriol. 178: 7152-7158, 1996). Northern blot experiments revealed a length of approximat ely 800 bases for each transcript of rbr and sod of C. perfringens. Thus, r br and sad each represent a monocistronic operon. Their transcription start points were located by primer extension analyses. sod transcription was sh own to depend on the growth phase, and it reached a maximum during the tran sition from log phase to stationary phase. Neither sod nor rbr transcriptio n was influenced by oxidative stress.