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Intracellular development of choleraphage phi 149 under permissive and nonpermissive conditions: an electron
S Majumdar1, S N Dey, R Chowdhury
1Biophysics Division, Indian Institute of Chemical Biology, Calcutta.
Abstract:
Intracellular development of choleraphage phi 149 following infection of Vibrio cholerae and Vibrio eltor cells under different conditions was examined by thin-section electron microscopy. Degradation of the host DNA following infection and formation of mature phage particles inside the infected cells were demonstrated. The concatemeric DNA intermediate formed during intracellular replication of phi 149 DNA in permissive hosts was resolved. In confirmation of biochemical evidence, no concatemeric DNA intermediate was observed for infection in high-phosphate medium.
Insights
Researchers studied choleraphage phi 149 infecting Vibrio cholerae and Vibrio eltor cells. They observed host DNA degradation, phage particle formation, and a specific DNA intermediate, which was absent in high-phosphate conditions.
Area of Science:
- Microbiology
- Virology
- Molecular Biology
Background:
- Choleraphage phi 149 is a bacteriophage that infects Vibrio cholerae and Vibrio eltor.
- Understanding phage-host interactions is crucial for controlling bacterial infections.
Purpose of the Study:
- To investigate the intracellular development of choleraphage phi 149 in Vibrio cholerae and Vibrio eltor.
- To examine the role of host DNA and DNA intermediates during phage replication under varying conditions.
Main Methods:
- Thin-section electron microscopy was used to visualize intracellular phage development.
- Analysis of DNA replication intermediates during phage infection.
Main Results:
- Demonstrated degradation of host Vibrio DNA post-infection.
- Observed the formation of mature phage phi 149 particles within infected cells.
- Resolved the concatemeric DNA intermediate during replication in permissive hosts.
- Confirmed the absence of this concatemeric DNA intermediate in high-phosphate medium.
Conclusions:
- Choleraphage phi 149 undergoes complete intracellular development, including host DNA degradation and progeny phage formation.
- The presence of a concatemeric DNA intermediate is host-dependent and influenced by medium composition (e.g., phosphate levels).