Related Experiment Videos
Mode of action of bacteriophage phi 149 on cholera and El Tor vibrios
Abstract:
Bacteriophage phi 149 which was propagated in Vibrio cholerae (classical) OGAWA 154 strain, killed Vibrio cholerae (El Tor) strain MAK 757 without phage propagation. El Tor vibrios underwent a small degree of lysis only when infected by the phage phi 149 at a high multiplicity of infection and lost their viability at a rate-dependent multiplicity of phage infection. Evidence was obtained with 32P-labelled bacteriophage phi 149 for penetration of phage DNA into both bacterial strains. In host strain (OGAWA 154) phage particle synthesis occurred normally. In El Tor strain MAK 757 the phage DNA was not degraded but its expression was blocked. The killing effect of phi 149 on El Tor strain MAK 757 is supposed to be due to damage of the cytoplasmic membrane, which could not be repaired under the influence of phage information. This was indicated by a blockage of cellular respiration and RNA and protein synthesis.
Insights
Bacteriophage phi 149 kills Vibrio cholerae El Tor by blocking phage DNA expression and damaging the cell membrane, inhibiting respiration and synthesis. This phage shows potential for controlling El Tor strains.
Area of Science:
- Microbiology
- Virology
- Molecular Biology
Background:
- Bacteriophages are viruses that infect bacteria.
- Vibrio cholerae causes cholera, a significant public health concern.
- Understanding phage-host interactions is crucial for developing phage therapy.
Purpose of the Study:
- To investigate the interaction of bacteriophage phi 149 with Vibrio cholerae strains.
- To elucidate the mechanism of bacteriophage phi 149-mediated killing of Vibrio cholerae El Tor.
- To determine the fate of phage DNA within different Vibrio cholerae strains.
Main Methods:
- Propagation of bacteriophage phi 149 in Vibrio cholerae classical OGAWA 154.
- Infection of Vibrio cholerae El Tor MAK 757 with bacteriophage phi 149 at various multiplicities.
- Use of 32P-labelled bacteriophage phi 149 to track DNA penetration.
- Assessment of bacterial viability, lysis, respiration, and nucleic acid/protein synthesis.
Main Results:
- Bacteriophage phi 149 effectively killed Vibrio cholerae El Tor MAK 757 without propagation.
- El Tor strain lysis was dependent on high multiplicity of infection and phage concentration.
- Phage DNA penetrated both OGAWA 154 and MAK 757 strains.
- Phage DNA expression was blocked in El Tor MAK 757, leading to inhibited respiration and synthesis.
- Damage to the cytoplasmic membrane was observed in El Tor cells.
Conclusions:
- Bacteriophage phi 149 exhibits bactericidal activity against Vibrio cholerae El Tor.
- The killing mechanism involves blocking phage DNA expression and inducing cytoplasmic membrane damage.
- This phage demonstrates potential as a therapeutic agent against specific Vibrio cholerae strains.