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High molecular weight phosphorus compound in nucleic acid extracts of the slime mold Physarum polycephalum
Abstract:
Orthophosphate labeled with (32)P was added to the growth medium of the plasmodia of Physarum polycephalum. The nucleic acid extracts of such plasmodia contained (32)P that was not removed by nuclease, protease, or amylase. This labeled material was shown to be separable from nucleic acids, could be eluted from a methylated albumin-kieselguhr column at 0.5 m NaCl, was of high molecular weight, and had several characteristics in common with polyphosphate. A fraction of this polyphosphate-like material was also found in extracts of isolated nuclei.
Insights
Physarum polycephalum incorporates 32P-orthophosphate into a high-molecular-weight polyphosphate-like substance. This material, distinct from nucleic acids, is also present in isolated nuclei.
Area of Science:
- Biochemistry
- Cell Biology
- Mycology
Background:
- Physarum polycephalum is a model organism for studying cellular processes.
- Understanding phosphate metabolism is crucial for cellular function.
Purpose of the Study:
- To investigate the fate of orthophosphate in Physarum polycephalum.
- To characterize novel phosphate-containing compounds in the organism.
Main Methods:
- Labeling plasmodia with 32P-orthophosphate.
- Extraction and purification of labeled compounds.
- Chromatographic separation using methylated albumin-kieselguhr columns.
- Enzymatic digestion with nucleases, proteases, and amylases.
Main Results:
- A 32P-labeled material, resistant to enzymatic degradation, was identified.
- This substance exhibited characteristics of polyphosphate and was separable from nucleic acids.
- High molecular weight and elution at 0.5 M NaCl on a methylated albumin-kieselguhr column were observed.
- A fraction of this polyphosphate-like material was detected in isolated nuclei.
Conclusions:
- Physarum polycephalum synthesizes a polyphosphate-like compound from orthophosphate.
- This compound is distinct from nucleic acids and is found within the nucleus.