Identification of genes regulated by prolonged acid exposure in Helicobacter pylori

To investigate the influence of prolonged acid exposure on the gene express ion, transcripts of Helicobacter pylori, grown under pH 5.5 and pH 7.4 for five successive passages, were analysed by differential display PCR. Eight genes were regulated by prolonged acid exposure. These genes included topA, tufB, ureB, flaA, atoE in the H. pylori genome and a cDNA fragment with 54 % identity of the predicted amino acid sequence to a Bacillus cereus YkoW p rotein. The remaining two cDNA fragments had no significant homology to kno wn sequences. Our data suggest that most of these genes might be required f or the resistance of H. pylori to prolonged acid exposure. (C) 2001 Federat ion of European Microbiological Societies. Published by Elsevier Science B. V. All rights reserved.