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Observations of globular membranes and apparent elementary particles in rat mitochondria, in situ
Abstract:
Ultrastructural details of rat skeletal muscle, fixed in a PIPES-buffered glutaraldehyde solution, included the globular configuration of the outer and inner mitochondrial membranes as well as small transparent particles (80--100A diameter) distributed throughout the matrix of these organelles. The size of these particles and their intimate relationship with the innermost surface of the cristae suggests that they may represent an in situ visualization of the elementary particles once reported in intact cells and frequently observed in negatively stained mitochondrial preparations. The membrane configurations and particles were not discernable in these tissues when a phosphate buffer system was used in the fixation regimen.
Insights
PIPES buffer fixation revealed mitochondrial elementary particles in rat skeletal muscle ultrastructure. Phosphate buffers failed to preserve these structures, highlighting fixation's critical role in visualizing cellular components.
Area of Science:
- Cell Biology
- Biochemistry
- Microscopy
Background:
- Mitochondrial structure and function are key to cellular energy production.
- Previous studies suggested the presence of elementary particles within mitochondria.
- Fixation techniques significantly impact ultrastructural preservation.
Purpose of the Study:
- To investigate the ultrastructural details of rat skeletal muscle mitochondria.
- To identify and characterize particles within the mitochondrial matrix.
- To evaluate the effect of different buffer systems on ultrastructural preservation.
Main Methods:
- Rat skeletal muscle tissue was fixed using glutaraldehyde in a PIPES-buffered solution.
- Ultrastructural analysis was performed using electron microscopy.
- Comparative analysis with tissues fixed using a phosphate buffer system was conducted.
Main Results:
- PIPES buffer fixation preserved the globular configuration of mitochondrial membranes.
- Small, transparent particles (80-100Å diameter) were observed within the mitochondrial matrix.
- These particles were closely associated with the inner mitochondrial membrane surface (cristae).
- Phosphate buffer fixation resulted in indiscernible membrane configurations and particles.
Conclusions:
- The observed particles likely represent in situ visualization of mitochondrial elementary particles.
- PIPES buffer is superior to phosphate buffer for preserving mitochondrial ultrastructure and associated particles.
- Fixation buffer choice is crucial for accurate ultrastructural studies of mitochondria.