Related Experiment Videos
Light and electron microscopy of laser microirradiated nucleoli and nucleoplasm in tissue culture cells
Abstract:
This manuscript describes in precise detail the ultrastructural alterations produced as a result of laser micoirradiation of nucleoli and nucleoplasm of tissue culture cells. Because of the general difficulty of single cell recovery, flat embedding, and serial sectioning, very few studies have ever been conducted on microbeam irradiated cells; yet the use of the microbeam technique has become widespread in functional studies of the nucleus. The results presented here demonstrate two classes of lesion material: small spherical electron dense bodies 0.05-0.02 mum in diameter and a larger, more irregular electron dense material up to 1 mum in length. The occurrence of these different types of lesion materials is described in control irradiated nucleoli and nucleoplasm, irradiated nucleoli and nucleoplasm in quinacrine treated cells, irradiated nucleoli and nucleoplasm in actinomycin D treated cells, and irradiated nucleoli and nucleoplasm in combined actinomycin D and quinacrine treated cells. In all the cells in which actinomycin D was employed, nucleoli were selectively irradiated in either their granular or fibrillar zones. The results of the ultrastructural studies are discussed in light of earlier functional studies.
Insights
Laser microirradiation of cell nuclei reveals two types of ultrastructural damage. These findings provide insights into nuclear functional studies using microbeam techniques and the effects of drugs like actinomycin D.
Area of Science:
- Cell Biology
- Microscopy
- Laser Technology
Background:
- Microbeam irradiation is crucial for nuclear functional studies.
- Few studies detail ultrastructural changes in microbeam-irradiated cells due to technical challenges.
- Understanding these changes is key to interpreting functional data.
Purpose of the Study:
- To precisely describe ultrastructural alterations from laser microirradiation of nucleoli and nucleoplasm.
- To investigate the impact of quinacrine and actinomycin D on these alterations.
- To correlate ultrastructural findings with functional studies.
Main Methods:
- Laser microirradiation of tissue culture cells.
- Electron microscopy for ultrastructural analysis.
- Serial sectioning and flat embedding techniques.
- Treatment with quinacrine and actinomycin D.
Main Results:
- Identified two distinct types of laser-induced lesions: small spherical (0.05-0.02 µm) and larger irregular electron-dense material (up to 1 µm).
- Observed these lesions in control, quinacrine-treated, actinomycin D-treated, and combined-treated cells.
- Actinomycin D treatment allowed selective irradiation of nucleolar granular or fibrillar zones.
Conclusions:
- Laser microirradiation induces specific ultrastructural changes in the nucleus.
- Drug treatments modulate the response to microirradiation.
- These ultrastructural details enhance the interpretation of functional microbeam studies.