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Dominance relationships in mixedly infected Bacillus subtilis
Journal of Virology
|April 1, 1972
Summary
Bacteriophage interactions in Bacillus subtilis reveal complex dominance patterns. Phage SP02(c1) is consistently subordinate, while the dominance of phages beta22 and SP82 depends on the specific bacterial host strain used in mixed infections.
Area of Science:
- Microbiology
- Virology
- Bacteriology
Background:
- Bacteriophages are viruses that infect bacteria and play crucial roles in microbial ecology and evolution.
- Mixed infections, where a host cell is infected by multiple phages, can lead to complex interactions including competition and interference.
- Understanding phage-phage interactions is essential for fields like phage therapy and microbial population control.
Purpose of the Study:
- To investigate the competitive interactions and dominance hierarchies among bacteriophages beta22, SP82, and SP02(c1) during mixed infections of Bacillus subtilis.
- To determine the influence of multiplicity of infection and order of addition on phage progeny yield.
- To assess the impact of different Bacillus subtilis host strains on phage dominance.
Main Methods:
- Mixed infection experiments were conducted using Bacillus subtilis strains 168 and SB11.
- Bacterial cells were infected with combinations of bacteriophages beta22, SP82, and SP02(c1) at varying multiplicities and orders of addition.
- Phage progeny yields were quantified to determine dominance and interference patterns.
Main Results:
- In Bacillus subtilis 168, bacteriophage SP02(c1) was subordinate to both SP82 and beta22, producing minimal progeny even when added first.
- The dominance between bacteriophages beta22 and SP82 was host-dependent.
- In Bacillus subtilis 168, SP82 dominated beta22, significantly reducing beta22 progeny. Conversely, in Bacillus subtilis SB11, beta22 dominated SP82, completely suppressing SP82 production.
Conclusions:
- Bacteriophage SP02(c1) exhibits consistent subordination in mixed infections with SP82 and beta22 in Bacillus subtilis.
- The outcome of mixed infections between bacteriophages beta22 and SP82 is strongly influenced by the Bacillus subtilis host strain, demonstrating host-mediated dominance.
- These findings highlight the complex interplay between phages and their hosts, with implications for phage ecology and potential applications.