Some properties of RNA from Physarum amoebae undergoing encystment: electrophoretic similarity to Acanthamoeba RNA.

Some properties of the RNA of myxamoebae-swarm cells of Physarum flavicomum undergoing microcyst formation, and during adenine inhibition of the developmental process, were compared. During the first 15 h incubation under encystment conditions, 11% more RNA was recovered from the adenine-inhibited cells (AIC) than from the normal control cells (NC), whereas the specific activity (SA) of the purified RNA from NC was 1.4 times higher than that from the AIC. Gel electrophoresis of purified total RNA revealed comigration of ribosomal RNAs (rRNA) of the myxamoebae with those of mouse kidney and liver, and diploid cells of P. flavicomum. In contrast to the apparently equivalent 18S and 28S pattern of the latter three RNAs, the quantity of the largest rRNA was significantly lower compared with that of the smaller (18S) rRNA in both NC and AIC myxamoebae-swarm cells. Total RNA from amoebae of a recent isolate of Acanthamoeba sp. quantitatively exhibited the same unusual pattern of rRNA distribution as the Physarum myxamoebae. A high pressure liquid chromatographic method was developed using a single solvent for the isocratic separation of the four major bases and seven methylated bases of RNA. Methylated adenine and guanine were detected in total RNA samples of myxamoebae of P. flavicomum. The mole % of uracil was slightly higher in the NC, whereas the mole % of adenine was slightly lower compared with that of the AIC. The guanine plus cytosine content of these purified total RNAs was about 61%.