Related Experiment Video
Updated: Sep 7, 2026
Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy
Published on: June 24, 2019
Macronuclear events in synchronously dividing Tetrahymena pyriformis
Abstract:
The macronuclei of synchronously dividing mass cultures of Tetrahymena pyriformis (strain WH(6)) were examined with the electron microscope for changes during two division cycles. Samples were prepared at 30-minute intervals for a period of 8(1/2) hours which included the time required to induce synchrony by five heat shocks (4(1/2) hours). The interphase macronucleus contains peripheral, crescent-shaped nucleoli and evenly distributed chromatin bodies. Centrally located RNA bodies, composed of fibers, appear 1 to 2 hours following the initial heat shock. They are completely destroyed with ribonuclease whereas the nucleoli are only partially so. Following the third heat shock the RNA bodies move to the periphery and disintegrate; the nucleoli aggregate and form blebs which protrude into the cytoplasm where they appear to pinch off and may contribute to the cytoplasmic ribonucleic acid. Cytokinesis does not occur at this time. Instead the nuclear events are repeated during the 4th and 5th hours, even though the heat shocks are terminated at 4(1/2) hours. Cytokinesis takes place at about 6 hours. The second division occurs about 2(1/2) hours later during which all the macronuclear events noted above are repeated.
Insights
Electron microscopy revealed dynamic macronuclear changes in Tetrahymena pyriformis during cell division. RNA bodies and nucleoli undergo significant structural alterations and reorganization preceding cytokinesis.
Area of Science:
- Cell Biology
- Microbiology
- Molecular Biology
Background:
- Tetrahymena pyriformis is a model organism for studying nuclear dynamics.
- Understanding macronuclear behavior is crucial for comprehending cell division processes.
Purpose of the Study:
- To investigate the ultrastructural changes in Tetrahymena pyriformis macronuclei during synchronous cell division.
- To characterize the behavior of nucleoli and RNA bodies in response to heat shock and cell cycle progression.
Main Methods:
- Synchronous mass cultures of Tetrahymena pyriformis (strain WH(6)) were utilized.
- Electron microscopy was employed to examine macronuclear morphology at 30-minute intervals over 8.5 hours.
- Heat shocks were used to induce synchrony, followed by observation through two division cycles.
Main Results:
- Interphase macronuclei exhibit peripheral nucleoli and distributed chromatin.
- Centrally located RNA bodies appear post-heat shock and are sensitive to ribonuclease.
- Macronuclear events, including RNA body disintegration and nucleolar blebbing, are repeated during subsequent division cycles.
Conclusions:
- Macronuclear structure undergoes significant, cyclical changes during Tetrahymena pyriformis division.
- RNA bodies and nucleoli play distinct roles in nuclear reorganization and potentially contribute to cytoplasmic components.
- The observed nuclear events are tightly regulated and repeated across multiple division cycles.
More Related Videos
Related Concept Videos
01:35Mitosis and Cytokinesis
The processes of the cell cycle occur over approximately 24 hours (in typical human cells) and in two major distinguishable stages. The...
02:03Mitosis and Cytokinesis
The processes of the cell cycle occur over approximately 24 hours (in typical human cells) and in two major distinguishable stages. The...
02:23Meiosis II
02:02Meiosis II
The timing and cell division patterns of meiosis differ between males and females. In male meiosis, the centrosomes are part of the formation of the meiotic spindle. However, in oocytes, including that of humans, Drosophila,...
01:20Binary Fission
01:26Binary Fission