Related Experiment Videos
Some properties of RNA from Physarum amoebae undergoing encystment: electrophoretic similarity to Acanthamoeba RNA
1Department of Biology, University of Houston, Texas 77204-5513.
Abstract:
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%.
Insights
Physarum flavicomum RNA during microcyst formation shows altered ribosomal RNA patterns and base composition when adenine synthesis is inhibited. These changes in RNA properties offer insights into cellular development and regulation.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Studying RNA properties during cellular differentiation, like microcyst formation in Physarum flavicomum, is crucial for understanding developmental regulation.
- Adenine inhibition provides a tool to probe the impact of specific metabolic pathways on RNA synthesis and composition.
Purpose of the Study:
- To compare RNA properties in Physarum flavicomum myxamoebae-swarm cells during normal microcyst formation versus adenine inhibition.
- To characterize the ribosomal RNA (rRNA) profile and base composition of RNA under these conditions.
Main Methods:
- Gel electrophoresis was used to analyze ribosomal RNA (rRNA) patterns.
- High-pressure liquid chromatography (HPLC) with a single solvent system was developed for RNA base analysis.
- Quantification of total RNA and specific activity was performed.
Main Results:
- Adenine-inhibited cells (AIC) showed 11% more RNA than normal control cells (NC), but NC RNA had 1.4 times higher specific activity.
- Both NC and AIC myxamoebae exhibited an unusual rRNA pattern with a lower quantity of the largest rRNA compared to the 18S rRNA, a pattern also observed in Acanthamoeba sp.
- Methylated adenine and guanine were detected, with slightly higher uracil in NC and slightly lower adenine in AIC. Guanine plus cytosine content was approximately 61%.
Conclusions:
- Physarum flavicomum myxamoebae display a unique rRNA distribution pattern, distinct from typical mammalian rRNA profiles.
- Adenine inhibition alters RNA yield and specific activity, suggesting a role for adenine metabolism in regulating RNA synthesis during encystment.
- The developed HPLC method allows for efficient separation and analysis of RNA bases, including methylated forms.