Evidence for message reading from a unique strand of pneumococcal DNA.

FIG. 1.-Ultraviolet pH 12.15 2 photographs and densitometer tracings of typical pneumococcal DNA bands in CsCl, with reference bands of dAT polymer (1) and M. lysodeikticus DNA (2). Top: pH 12.15; mid. N D die: dAT plus nativeandi heat-enatured pneumopH7 coccal DNA, pH 7; bottom: J native, pH 7. Centrifuged 21 hr at 44,770 rpm, 2 25.00C. The dAT andM. lysodetkticus bands at pH 12 are still rather sharp, whereas the pneunococcal band suggests overlapping peaks. The widths at alf maximum are in the ratio 1:1.2:1.9 for native, denatured at pH 7, and pH 12, respectively. Tracings were drawn directly on the figure by a Joyce-Loebl microdensitometer.