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Membrane potential changes during the first steps of coliphage infection
Summary
Bacterial phages T4 and T5 trigger changes in host cell membrane potential upon adsorption. Bacteria adapt by repolarizing, achieving a stable reduced membrane potential regardless of initial depolarization intensity.
Area of Science:
- Microbiology
- Molecular Biology
- Biophysics
Background:
- Bacterial cell membranes are crucial for cellular processes.
- Bacteriophages (phages) are viruses that infect bacteria.
- Phage-host interactions can significantly alter bacterial physiology.
Purpose of the Study:
- To investigate the impact of phage adsorption on bacterial cytoplasmic membrane potential.
- To understand the host cell's response to phage-induced membrane depolarization.
- To elucidate the signaling mechanisms involved in phage-bacterial interactions.
Main Methods:
- Monitoring changes in bacterial membrane potential following phage T4 and T5 adsorption.
- Analyzing the relationship between phage adsorption levels and membrane potential dynamics.
- Assessing the influence of various experimental conditions on the observed phenomena.
Main Results:
- Phage adsorption caused immediate partial depolarization of the host cytoplasmic membrane.
- Bacteria initiated repolarization, reaching a new steady state of reduced membrane potential.
- The rate and extent of repolarization were proportional to the initial depolarization, with a constant time to reach the new steady state.
- These effects were independent of phage type, DNA presence, injection process, temperature, external pH, and pre-infectious membrane potential.
Conclusions:
- Phage adsorption likely triggers a signal transmitted to the cytoplasmic membrane.
- A chemical modification induced by initial phage adsorption may cause refractoriness to secondary depolarization and shut off the initial depolarization.
- The host response is a regulated process, adapting to the intensity of phage-induced membrane potential changes.