Multiple adsorptions shape collective T-even phage lysis dynamics: Insights from an individual-based model

Area of Science:

• Microbiology
• Computational Biology
• Mathematical Modeling

Background:

• T-even bacteriophages exhibit complex behaviors like lysis from without (LO) and lysis inhibition (LIN) dependent on multiplicity of infection (MOI).
• Understanding these MOI-dependent dynamics is crucial for predicting phage-host interactions and population outcomes.

Purpose of the Study:

• To develop an individual-based model capturing MOI-dependent dynamics of T-even bacteriophage infections.
• To investigate the roles of lysis from without resistance (LOR) and lysis inhibition (LIN) in bacterial response to phage attack.
• To explore the impact of spatial structure and secondary adsorption thresholds on bacterial colony survival.

Main Methods:

• Developed a phenomenological, individual-based model incorporating LO resistance (LOR) and lysis inhibition (LIN) with stochastic variability.
• Simulated batch culture growth to observe collective phenomena like synchronized collapse.
• Applied the model to spatially structured bacterial colonies to analyze phage-host dynamics in situ.

Main Results:

• The model successfully reproduced experimentally observed multiple peaks in phage production.
• Demonstrated that synchronized collapse of LINed cultures can emerge in batch cultures under specific LOR conditions (LORO).
• Found that spatial dynamics and LO thresholds, particularly LORO, can influence colony survival by modulating local MOI.

Conclusions:

• Individual-based modeling provides a powerful framework for understanding complex MOI-dependent phage-host dynamics.
• Spatial structure and secondary adsorption thresholds significantly impact bacterial population outcomes during phage infection.
• The interplay between lysis from without resistance and lysis inhibition is critical for bacterial survival strategies against bacteriophages.