Incorporation of glucose carbon into ribonucleotides of axenic Entamoeba histolytica.

Axenic Entamoeba histolytica grown with (UL-14C)glucose in TP-S-1 medium were capable of biosynthesizing ribose from labeled glucose. RNA isolated by phenol extraction was hydrolyzed to the ribonucleotide level by alkaline hydrolysis. The hydrolysate, chromatographed on ion exchange resins, yielded AMP, GMP, and UMP, but not CMP containing labeled glucose carbon. The present nucleotide composition of the isolated amebal RNA was, respectively, as follows, CMP, 0.20; GMP, 0.22; AMP, 0.30; UMP, 0.29. The location of all the radiolabel in each ribonucleotide was the ribose moiety. The relative specific incorporation of glucose carbon into AMP, GMP, and UMP was 0.47, 0.05, and 0.10, respectively. These results suggest that the bulk of amebal nucleic acid precursors are obtained as preformed nucleosides and/or nucleotides from TP-S-1 medium. The mean RNA content per milliliter packed cells of amebae was 4.2 +/- 0.2 mg.