Unveiling microbial single-cell growth dynamics under rapid periodic oxygen oscillations

Area of Science:

• Microbiology
• Cell Biology
• Biophysics

Background:

• Microbial metabolism and growth are fundamentally linked to oxygen availability.
• Natural environments expose microbes to fluctuating oxygen (O2) levels, impacting their physiology.
• Current understanding of single-cell responses to dynamic O2 is limited by observational challenges.

Purpose of the Study:

• To investigate microbial growth dynamics at single-cell resolution under precisely controlled, fluctuating oxygen conditions.
• To develop and utilize a microfluidic platform for time-resolved analysis of microbial responses to dynamic O2.
• To correlate individual cell growth with specific, local oxygen microenvironments.

Main Methods:

• Development of a multilayer microfluidic device for controlled gas transfer and microbial cultivation.
• Automated time-lapse microscopy combined with deep-learning image analysis for spatiotemporally resolved growth data.
• Precise monitoring and rapid switching of oxygen concentrations (within tens of seconds) to study cellular responses.

Main Results:

• Demonstrated ability to cultivate microbes under constant, dynamic, and oscillating oxygen conditions.
• Obtained single-cell resolution growth data linked to specific local oxygen concentrations.
• Observed distinct growth dynamics in *Escherichia coli* microcolonies subjected to varying oxygen oscillation periods, including response and recovery phases.

Conclusions:

• The developed microfluidic platform enables unprecedented systematic study of microbial adaptation to fluctuating oxygen.
• Insights into single-cell responses to dynamic oxygen environments are crucial for understanding microbial ecology and evolution.
• This approach provides a foundation for future research into complex microbial behaviors under variable environmental conditions.