Quantification of imported DNA into <i>H</i>. <i>pylori</i> cells.

<p>A, Cy3 image of single Cy3-labelled λ DNA molecules, stained in yellow; B, DIC/Cy3 overlay image of <i>H</i>. <i>pylori</i> J99 after 10 min of DNA uptake under microaerobic conditions; C, results of the quantitative analysis of DNA uptake. For <i>H</i>. <i>pylori</i>, fluorescence intensity in single DNA foci (red) and in whole cells (blue) was determined in two different wild type strains (N6 and J99) after microaerobic growth in TSB-FBS into competent phase. D, histogram of the number of foci per cell. Grey bars, strain N6; black bars, strain J99. Fluorescence intensity was compared to that of single λ DNA molecules and expressed as imported kb. The images were acquired using a Zeiss Axio Observer Z1 and ZEN software, blue edition, version 2.0.0.0. n_cells = 928 or 1483 and n_foci = 1903 or 1740 were analyzed for J99 or N6, respectively.