Bistability and phase variation in Salmonella enterica

Area of Science:

• Microbiology
• Bacterial Genetics
• Epigenetics

Background:

• Cell-to-cell gene expression variability in bacteria can be due to noise or programmed bistability.
• Bistability, if heritable, forms bacterial lineages, and if reversible, is termed phase variation.
• Mechanisms include genetic (e.g., DNA rearrangement) and epigenetic factors like DNA methylation or stable feedback loops.

Purpose of the Study:

• To review examples of bistability and phase variation in Salmonella enterica.
• To discuss the adaptive significance of these phenomena in bacterial populations.

Main Methods:

• Literature review of studies on bacterial gene expression bistability and phase variation.
• Analysis of examples from Salmonella enterica.

Main Results:

• Salmonella enterica exhibits programmed bistability and phase variation through genetic and epigenetic mechanisms.
• Heritable DNA methylation patterns and stable feedback loops contribute to lineage formation.
• These phenomena can play adaptive roles, though some are speculative.

Conclusions:

• Bacterial bistability and phase variation are crucial for generating heritable traits and adapting to environments.
• Understanding these mechanisms in Salmonella provides insights into bacterial population dynamics and evolution.