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A Method for Obtaining Serial Ultrathin Sections of Microorganisms in Transmission Electron Microscopy
Published on: January 17, 2018
Abstract:
Gastrocnemius muscles taken from decapitated mice at various intervals after death and from mice killed by 2,4-dinitrophenol or mono-iodoacetic acid injection to induce rigor mortis soon after death, were observed by electron microscopy. The prominent appearance of many fine cross striations in the myofibrils (occurring about every 400 A) was considered to be characteristic of rigor mortis. These striations were caused by minute granules studded along the surfaces of both thick and thin filaments and appeared to be the bridges connecting the 2 kinds of filaments and accounted for the hardness and rigidity of the muscle.
Insights
Electron microscopy revealed fine cross striations in mouse gastrocnemius muscles during rigor mortis. These striations, caused by granules bridging thick and thin filaments, explain muscle rigidity after death.
Area of Science:
- Muscle physiology
- Electron microscopy
- Rigor mortis
Background:
- Rigor mortis is a postmortem stiffening of muscles.
- The underlying ultrastructural changes in rigor mortis are not fully understood.
Purpose of the Study:
- To investigate the ultrastructural changes in mouse gastrocnemius muscles during rigor mortis using electron microscopy.
- To identify the structural basis for muscle rigidity in rigor mortis.
Main Methods:
- Gastrocnemius muscles were obtained from mice at various postmortem intervals.
- Muscles were also obtained from mice injected with 2,4-dinitrophenol or mono-iodoacetic acid to induce rapid rigor mortis.
- Samples were examined using electron microscopy.
Main Results:
- Electron microscopy revealed prominent fine cross striations in myofibrils, approximately every 400 Angstroms, in muscles undergoing rigor mortis.
- These striations were attributed to minute granules on thick and thin filaments.
- These granules appeared to form bridges between the filaments, causing muscle hardness and rigidity.
Conclusions:
- The observed fine cross striations are characteristic ultrastructural markers of rigor mortis.
- Granular bridges between thick and thin filaments are the primary cause of muscle rigidity during rigor mortis.
