Abstract
The microfluidic mother machine platform has attracted much interest for its potential in studies of bacterial physiology, cellular organization, and cell mechanics. Despite numerous experiments and development of dedicated analysis software, differences in bacterial growth and morphology in narrow mother machine channels compared to typical liquid media conditions have not been systematically characterized. Here we determine changes in E. coli growth rates and cell dimensions in different sized dead-end microfluidic channels using high resolution optical microscopy. We find that E. coli adapt to the confined channel environment by becoming narrower and longer compared to the same strain grown in liquid culture. Cell dimensions decrease as the channel length increases and width decreases. These changes are accompanied by increases in doubling times in agreement with the universal growth law. In channels 100 μm and longer, cell doublings can completely stop as a result of frictional forces that oppose cell elongation. Before complete cessation of elongation, mechanical stresses lead to substantial deformation of cells and changes in their morphology. Our work shows that mechanical forces rather than nutrient limitation are the main growth limiting factor for bacterial growth in long and narrow channels.
| Original language | English |
|---|---|
| Article number | 871 |
| Journal | Frontiers in Microbiology |
| Volume | 9 |
| Issue number | MAY |
| DOIs | |
| State | Published - May 1 2018 |
Funding
The authors thank Cees Dekker and Fabai Wu for the generous gift of the strain and Ariel Amir, Maxim Lavrentovich, Jaana Männik, Bryant Walker, Conrad Woldringh, and Arieh Zaritsky for discussions and critical reading the manuscript. Authors acknowledge technical assistance and material support from the Center for Environmental Biotechnology at the University of Tennessee. A part of this research was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. This work has been supported in part by NSF research grant MCB-1252890. The authors thank Cees Dekker and Fabai Wu for the generous gift of the strain and Ariel Amir, Maxim Lavrentovich, Jaana M?nnik, Bryant Walker, Conrad Woldringh, and Arieh Zaritsky for discussions and critical reading the manuscript. Authors acknowledge technical assistance and material support from the Center for Environmental Biotechnology at the University of Tennessee. A part of this research was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. This work has been supported in part by NSF research grant MCB-1252890.
Keywords
- Cell wall
- Mechanics of cell growth
- Microfluidics
- Mother machine
- Nutrient shielding
- Peptidoglycan synthesis