Quantifying plasmid dynamics using single-cell microfluidics and image bioinformatics.

Area of Science:

• Bacterial Ecology and Evolution
• Microfluidics and Cell Biology

Background:

• Multicopy plasmids are key drivers of bacterial adaptation, evolution, and gene amplification.
• Studying population-level consequences of plasmid dynamics in individual cells is experimentally challenging.
• Advances in microscopy and microfluidics offer new avenues for real-time gene expression analysis.

Purpose of the Study:

• To describe the development and application of microfluidic systems for studying multicopy plasmid dynamics.
• To illustrate the utility of microfluidics in analyzing bacterial evolution under selective pressures.
• To investigate the stochastic nature of plasmid segregation and replication.

Main Methods:

• Utilized an image-based flow cytometer to assess allele distribution under selection.
• Employed a mother-machine microfluidic device for time-series single-cell fluorescence intensity measurements.
• Used a microchemostat to track bacterial lineages and reconstruct allele frequency distributions.

Main Results:

• Demonstrated microfluidic systems' capability to analyze multicopy plasmid dynamics in single cells and populations.
• Provided evidence for the inherently stochastic processes of plasmid segregation and replication.
• Evaluated allele frequency distributions under various selective pressures using lineage reconstruction.

Conclusions:

• Microfluidics provides powerful tools for dissecting the population-level impacts of plasmid dynamics in bacteria.
• Understanding plasmid dynamics is essential for comprehending bacterial adaptation and evolutionary trajectories.
• The stochastic nature of plasmid behavior significantly influences bacterial evolutionary outcomes.