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Updated: Jul 26, 2026

Purification of Mitochondria from Yeast Cells
Published on: August 24, 2009
Fibrous component of yeast mitochondria
1Centre de Génétique Moléculaire, Université Pierre et Marie Curie, Gif-sur-Yvette, France.
Abstract:
An intramitochondrial fibrous component (IMF) was consistently detected by electron microscopy in all eight strains of yeast examined, either respiratory competent or deficient, and including two species, Saccharomyces cerevisiae and S. uvarum. IMF was always found assembled into a layer 20 nm in thickness. In respiratory-deficient mutants, multiple IMF layers roll up concentrically to give rise to cylindrical inclusion bodies which attain several micrometers in length. In normal respiring yeasts, IMF occurs in close association with cristae to elaborate composite structures in which multiple parallel IMF layers are sandwiched between a pair of cristae. Evidence is presented to demonstrate the extramitochondrial origin of IMF.
Insights
An intramitochondrial fibrous component (IMF) was found in all yeast strains. This structure, 20 nm thick, forms inclusion bodies in deficient mutants and composite structures with cristae in normal yeasts, originating externally.
Area of Science:
- Mitochondrial biology
- Yeast genetics
- Cellular ultrastructure
Background:
- Mitochondria are crucial organelles for cellular respiration.
- Yeast models are widely used to study mitochondrial function.
- The internal structure of yeast mitochondria is not fully characterized.
Purpose of the Study:
- To investigate the presence and structure of a novel intramitochondrial fibrous component (IMF).
- To determine the association of IMF with mitochondrial cristae and its role in different yeast strains.
- To elucidate the origin of IMF.
Main Methods:
- Electron microscopy was used to examine yeast mitochondrial ultrastructure.
- Eight strains of Saccharomyces cerevisiae and S. uvarum were analyzed.
- Comparative analysis was performed between respiratory-competent and deficient mutants.
Main Results:
- A consistent 20 nm thick intramitochondrial fibrous component (IMF) was detected in all yeast strains.
- Respiratory-deficient mutants displayed concentric IMF layers forming inclusion bodies.
- Respiratory-competent yeasts showed IMF associated with cristae in composite structures.
- Evidence indicated an extramitochondrial origin for IMF.
Conclusions:
- IMF is a conserved mitochondrial component in yeast with distinct structural roles.
- IMF assembly and association with cristae differ between respiratory-competent and deficient states.
- The extramitochondrial origin suggests IMF is imported into the mitochondrion.
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