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Electron microscopic observations on the penetration of Bdellovibrio bacteriovorus into gram-negative bacterial hosts
Abstract:
The progressive stages in Bdellovibrio bacteriovorus penetration into two strains of Escherichia coli were examined by use of electron microscopic techniques. The initial change observed in the ultrastructure of the host following parasitic attack was the swelling of the cell envelope at the site of attachment. The Bdellovibrio then appeared to pierce the center of this swelling, forming a pore in the outer wall layers of the host. The edges of this entry pore constricted the Bdellovibrio throughout its penetration into the host cell. Although partial disruption of the cytoplasmic membrane was always apparent, the parasite did not appear to actively penetrate through this barrier. An attempt is made to correlate the fine structural changes involved in penetration with the physiological data that have accumulated to date.
Insights
Bdellovibrio bacteriovorus penetrates Escherichia coli by forming a pore in the host
Area of Science:
- Microbiology
- Bacteriology
- Cell Biology
Background:
- Bdellovibrio bacteriovorus is a predatory bacterium.
- Understanding bacterial invasion mechanisms is crucial.
Purpose of the Study:
- To investigate the ultrastructural changes during Bdellovibrio bacteriovorus penetration into Escherichia coli.
Main Methods:
- Electron microscopy was used to examine the penetration process.
- Two strains of Escherichia coli were used as hosts.
Main Results:
- Bdellovibrio bacteriovorus attachment caused host cell envelope swelling.
- A pore formed in the outer wall, constricting the Bdellovibrio during entry.
- Cytoplasmic membrane disruption was observed but not active penetration.
Conclusions:
- The study details the Bdellovibrio bacteriovorus penetration mechanism at the ultrastructural level.
- Findings correlate structural changes with existing physiological data.