Single Cell Analysis of a Bacterial Sender-Receiver System

Area of Science:

• Microbiology
• Systems Biology
• Synthetic Biology

Background:

• Single-cell analysis offers insights into cellular heterogeneity and gene expression dynamics.
• Quorum sensing (QS) systems regulate bacterial behavior based on population density.
• Bacterial QS components from Aliivibrio fischeri are widely studied.

Purpose of the Study:

• To investigate bacterial gene expression dynamics at the single-cell level using a quorum sensing system.
• To quantitatively determine the response of engineered bacterial receivers to varying inducer concentrations.
• To characterize population heterogeneity and identify homogeneous subpopulations for detailed analysis.

Main Methods:

• Utilized microfluidics-based bacterial chemostats and fluorescence video microscopy.
• Tracked large numbers of bacteria over extended periods to establish lineages.
• Quantified gene expression responses to N-3-oxo-C6-homoserine lactone (AHL) and analyzed population distributions.

Main Results:

• Observed heterogeneous induction behavior within the bacterial population.
• Characterized AHL response curves and gene expression dynamics.
• Demonstrated that single-cell level responses are more cooperative than population-level responses.

Conclusions:

• Single-cell analysis reveals significant heterogeneity in bacterial gene expression responses.
• Focusing on homogeneous subpopulations provides a clearer understanding of cooperative gene expression.
• Engineered bacterial receivers can serve as sensitive biosensors for quantifying signaling molecules like AHL.