Stochastic receptor expression allows sensitive bacteria to evade phage attack. Part II: theoretical analyses.

Area of Science:

• Microbiology
• Theoretical Biology
• Evolutionary Dynamics

Background:

• Stochastic gene expression creates protein distribution diversity in bacteria.
• Focus on population mean overlooks minority cell importance under severe selection.
• Phenotype heterogeneity may explain bacterial persistence against selection pressures.

Purpose of the Study:

• Investigate if phenotype heterogeneity ensures bacterial population survival under phage pressure.
• Determine the duration of persistence before significant genetic mutation occurs.
• Analyze survival statistics of bacteria with diverse phage-receptor numbers facing phage attack.

Main Methods:

• Theoretical investigation of bacterial population survival statistics.
• Utilized Berg-Purcell theoretical results for phage-bacterium interactions.
• Compared theoretical calculations with experimental observations from Part I.

Main Results:

• A heterogeneous bacterial population exhibits significantly higher fitness than a homogeneous one when facing phage pressure.
• The number of phage receptors on bacterial cells influences survival rates.
• Minority cell properties are critical for population fate under severe selection.

Conclusions:

• Phenotype heterogeneity, specifically diverse phage-receptor numbers, enhances bacterial population resilience against phage attacks.
• Heterogeneity in bacterial populations is crucial for persistence, delaying the impact of genetic mutations.
• Understanding minority cell dynamics is vital for predicting population survival under selective pressures.