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Updated: Aug 14, 2026
A Method for Growing Bio-memristors from Slime Mold
Published on: November 2, 2017
Methylation is an early and necessary step in the sporulation programme of the slime mold Physarum polycephalum
Abstract:
Formation of sporangia can be induced in starved macroplasmodia of Physarum polycephalum by illumination. This process of morphogenesis which starts 9 h after the needed period of illumination can be prevented by the competitive inhibitors of methyltransferases S-adenosyl-homocysteine or L-ethionine, applied either directly by microinjection into the plasmodia or by addition to the medium. Because 5-azacytidine (aza-C) or 5-aza-2'-deoxycytidine (aza-dC) also prevent sporulation (in contrast to cytidine, 8-azaguanine (aza-G) or 6-aza-uridine (aza-U) it is suggested that DNA is the substrate for methylation. The injection technique allows one to determine the period of methylation (i.e. between the 3rd and 4th h of the cell differentiation process after the induction by illumination). Based on the correlation between methylation and genome expression, it is suggested that some genes must be repressed by methylation during this period.
Insights
Methylation is crucial for Physarum polycephalum sporulation. Inhibitors of methyltransferases and DNA methylation prevent sporangia formation, suggesting gene repression via methylation during cell differentiation.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Physarum polycephalum macroplasmodia undergo sporulation upon illumination after starvation.
- Sporangia formation is a key developmental process in the Physarum life cycle.
Purpose of the Study:
- To investigate the role of DNA methylation in the light-induced sporulation of Physarum polycephalum.
- To identify the timing of methylation during the cell differentiation process.
Main Methods:
- Induction of sporangia formation in starved macroplasmodia of Physarum polycephalum by illumination.
- Application of competitive inhibitors of methyltransferases (S-adenosyl-homocysteine, L-ethionine) and DNA methylation inhibitors (5-azacytidine, 5-aza-2'-deoxycytidine).
- Microinjection into plasmodia and addition to the medium to assess inhibitor effects.
- Precise timing of methylation using microinjection techniques.
Main Results:
- Inhibitors of methyltransferases and DNA methylation (5-azacytidine, 5-aza-2'-deoxycytidine) prevented sporulation.
- Cytidine, 8-azaguanine, and 6-aza-uridine did not prevent sporulation, supporting DNA as the methylation substrate.
- Methylation was determined to occur between the 3rd and 4th hour of cell differentiation post-illumination.
Conclusions:
- DNA methylation plays a critical role in regulating the light-induced sporulation of Physarum polycephalum.
- Gene repression through methylation is suggested to occur during a specific window of early cell differentiation.
- This study highlights the importance of epigenetic modifications in developmental processes.
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