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Polyamine synthesis and interconversion by the Microsporidian Encephalitozoon cuniculi
C J Bacchi1, S Lane, L M Weiss
1Haskins Laboratory, Pace University, New York, New York 10038, USA. cbacchi@pace.edu
The Journal of Eukaryotic Microbiology
|June 20, 2001
Summary
Encephalitozoon cuniculi spores exhibit active polyamine metabolism, synthesizing and interconverting key molecules like putrescine and spermidine. This eukaryotic-type pathway is inhibited by DFMO, suggesting potential therapeutic targets.
Area of Science:
- Microbiology and Parasitology
- Molecular Biology
- Biochemistry
Background:
- Polyamines are essential for cell growth and differentiation.
- Polyamine metabolism is a validated drug target in mammals and microorganisms.
- Limited knowledge exists regarding polyamine metabolism in microsporidia.
Purpose of the Study:
- To investigate polyamine metabolism in the microsporidian Encephalitozoon cuniculi.
- To characterize the enzymes involved in polyamine synthesis and interconversion.
- To assess the metabolic activity of different spore stages.
Main Methods:
- Cultivation of Encephalitozoon cuniculi in RK-13 cells.
- Purification of pre-emergent spores using Percoll gradients.
- Enzymatic assays using radiolabeled precursors and inhibitors (DFMO, DFMA).
Main Results:
- Pre-emergent spores synthesized putrescine, spermidine, and spermine from ornithine and methionine.
- Exogenous spermine was interconverted to spermidine and putrescine.
- Ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetdc) activities were detected and characterized.
Conclusions:
- Encephalitozoon cuniculi possesses a eukaryotic-type polyamine biosynthetic pathway.
- Pre-emergent spores are metabolically active in polyamine synthesis and interconversion.
- The pathway is sensitive to DL-alpha-difluoromethylornithine (DFMO), indicating potential for therapeutic intervention.