Wang A L, Wang C C
Mol Biochem Parasitol. 1985 Mar;14(3):323-35. doi: 10.1016/0166-6851(85)90060-x.
High molecular weight DNA samples free of contaminating proteins or RNA were obtained from Tritrichomonas foetus or Trichomonas vaginalis by lysing the cells in 4 M guanidinium thiocyanate before centrifuging in CsCl density gradient and then purifying the DNA band by NACS-37 column chromatography. The bulk DNA from either organism acted as a single component in ion-exchange chromatography, agarose gel electrophoresis, CsCl density gradient centrifugation and thermal denaturation. T. foetus DNA showed a melting temperature (Tm) of 82 degrees C corresponding to a 31% GC content whereas T. vaginalis DNA melted at 84 degrees C to suggest 36% GC. Both DNA samples demonstrated 35 to 42% hyperchromicity when fully melted. Cot analysis revealed the presence of repetitive sequences in both DNAs: approximately 46.7% in T. foetus DNA and 53.3% in T. vaginalis DNA. The unique sequences of these two protozoan DNAs are of a similar size of about 2.5 X 10(7) base pairs. Agarose gel electrophoresis of restriction fragments of the two purified DNA samples gave distinct banding patterns that were characteristic of the two species of protozoan parasites.
