Space- and time-resolved protein dynamics in single bacterial cells observed on a chip

Area of Science:

• Microbiology
• Cell Biology
• Biophysics

Background:

• Life cell imaging of bacteria is challenging due to small cell size and the need for a viable liquid environment.
• Obtaining space- and time-resolved data on protein dynamics requires advanced imaging techniques.
• Previous methods limited long-term observation of dynamic protein localization in single bacterial cells.

Purpose of the Study:

• To develop and validate a microfluidic chip-based method for high-resolution, time-lapse fluorescence imaging of bacterial cells.
• To monitor protein dynamics, including cytoplasmic and localized proteins, over extended periods and multiple cell divisions.
• To demonstrate the applicability of this approach for studying spatio-temporal protein localization in bacteria.

Main Methods:

• Utilized a poly(dimethylsiloxane) (PDMS) microfluidic chip for live bacterial cell imaging.
• Employed high-resolution time-lapse fluorescence imaging (TLFI) to capture dynamic cellular processes.
• Applied a novel gradient coating technique for efficient bacterial cell loading and a method to divide cells into sections for protein localization analysis.

Main Results:

• Successfully monitored the distribution of the cytoplasmic protein GcrA and the asymmetric localization of the DivK protein in S. meliloti cells.
• Tracked protein dynamics over at least two bacterial cell division cycles.
• Characterized DivK protein localization by dividing cells into four sections near the optical resolution limit.

Conclusions:

• The developed microfluidic chip and imaging approach enable long-term, high-resolution observation of protein dynamics in single bacterial cells.
• This method provides valuable spatio-temporal resolution for studying protein localization and bacterial cell biology.
• The technique is broadly applicable to diverse research questions in microbial cell dynamics.