Polyprenols of Aspergillus niger. Their characterization, biosynthesis and subcellular distribution.

Area of Science:

• Biochemistry
• Mycology

Background:

• Aspergillus niger is a model organism for studying fungal metabolism.
• Polyprenols, ubiquinones, and ergosterol are key isoprenoid compounds in fungi.

Purpose of the Study:

• To characterize the polyprenol complex in Aspergillus niger.
• To investigate the dynamics and cellular localization of isoprenoid compounds.

Main Methods:

• Spectrometric analysis to identify polyprenol structure.
• [2-(14)C]mevalonate incorporation to study turnover rates.
• Subcellular fractionation to determine localization.

Main Results:

• Polyprenol complex consists of exo-methylene-hexahydroprenols with 18-24 isoprene units.
• Ubiquinone complex is predominantly ubiquinone-9.
• Maximum polyprenol and mycelium yield at 9-10 days; ergosterol and ubiquinone peak at 8 days.
• Prenol turnover is slow, ergosterol is rapid, and ubiquinone is very rapid.
• Unesterified prenol is mitochondrial; esterified prenol is more widely distributed.

Conclusions:

• Aspergillus niger synthesizes a diverse polyprenol family.
• Isoprenoid compound turnover rates vary significantly, with ubiquinones showing the fastest metabolism.
• Cellular localization differs between unesterified and esterified prenols.