Related Experiment Videos
Ultrastructure of bacterial cells infected with bacteriophage PM2, a lipid-containing bacterial virus
Abstract:
The cytological pattern of infection of a host pseudomonad with PM2, a lipid-containing bacterial virus, was investigated by electron microscopy. Normal and infected cells frequently contain a myelin figure, which is found in the nucleoid region or at the periphery of the cell. The most striking finding in this investigation was that completed virions are found in the cell adjacent to or in association with the cytoplasmic membrane. This localization is precise; virions are not found elsewhere in infected cells. The completed virions occasionally appear to be attached to the cytoplasmic membrane. The virus contains a darkly staining core surrounded by a tripartite envelope of a thickness of approximately 70 A, which is identical to the thickness of the cytoplasmic membrane. Lysing cells appear to undergo extensive damage of the cytoplasmic membrane prior to rupture of the L layer of the cell wall.
Insights
Researchers studied the infection of Pseudomonas with the bacterial virus PM2 using electron microscopy. They found completed PM2 virions precisely localized at the host cell's cytoplasmic membrane, suggesting a specific interaction during viral replication.
Area of Science:
- Microbiology
- Virology
- Cell Biology
Background:
- Bacterial viruses, or bacteriophages, infect prokaryotic hosts.
- Pseudomonas species are common hosts for various bacteriophages.
- Understanding viral infection mechanisms is crucial for controlling bacterial pathogens.
Purpose of the Study:
- To investigate the cytological pattern of Pseudomonas infection by the bacterial virus PM2.
- To elucidate the precise localization of viral components within the host cell during infection.
Main Methods:
- Electron microscopy was employed to visualize the ultrastructure of infected Pseudomonas cells.
- Detailed imaging of normal and infected cells allowed for the observation of viral replication stages.
Main Results:
- Myelin figures were observed in both normal and infected Pseudomonas cells.
- Completed PM2 virions were consistently found associated with the cytoplasmic membrane.
- The viral envelope thickness was comparable to the host cell's cytoplasmic membrane.
Conclusions:
- The precise localization of PM2 virions at the cytoplasmic membrane suggests a specific interaction or assembly site.
- Damage to the cytoplasmic membrane precedes cell lysis, indicating its role in the final stages of infection.