Direct visualization of transformation by fluorescence microscopy.

<p>(<b>A</b>) Transforming activity of Cy3-DNA. Wildtype cells were exposed to the indicated concentrations of a 4.3 kb fragment containing the Sm^R mutation <i>rpsL41</i>, bearing or not a 5′ Cy3 label, and Sm^R transformants were scored. Black, unlabelled donor DNA; red, Cy3-DNA. (<b>B</b>) Direct visualization of transformation. (<i>Left</i>) Schematic of transformation. Cy3-DNA, red dot; fluorescent FtsZ-GFP ring depicted in green. (<i>Right</i>) Fluorescence time-lapse microscopy. The Cy3 and GFP fluorescence images were respectively false colored red and green and overlaid on phase contrast images. Two representative cells are shown. Time after DNA addition indicated in min.