Characteristics of Helicobacter pylori natural transformation

For Helicobacter pylori, which exhibits substantial genetic diversity, many strains are naturally competent for transformation by exogenous DNA. To be tter understand the mechanism of natural transformation and its role in the generation of diversity, we sought to systematically identify factors impo rtant for natural transformation in H. pylori. We now show that the highest frequency of H. pylori transformation occurs when DNA is introduced prior to exponential phase growth, and that it is a saturable phenomenon. That tr ansformation can be inhibited by DNA from Helicobacter (H. pylori and Helic obacter bills) but not Escherichia coli suggests specificity based on DNA s ource. Finally, the cag island was determined to be unnecessary for high-fr equency transformation. (C) 2000 Federation of European Microbiological Soc ieties. Published by Elsevier Science B.V. All rights reserved.