Experimental evolution of Escherichia coli in high osmolarity environments

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Abstract/Contents

Abstract: A ubiquitous feature of bacterial life is the stress of large osmotic pressure differentials across the cell envelope, yet little is known about how this turgor pressure affects growth. To explore the capacity for growth in different environments, a set of long-term evolution experiments were carried out with the model organism Escherichia coli over more than 200 generations in a variety of osmolytes and concentrations. To assess phenotypic changes in the evolved populations relative to the ancestor, we assayed growth rate via absorbance and identified populations with large changes in maximal growth rate or lag time. For these populations, we measured these population growth characteristics and cell morphology over many osmotic environments and across several genotypes within the population. We discovered several adaptations that were specific to the evolution osmolyte, while other adaptations were global. Based on these results, we hypothesize that osmolytes that can be metabolized will cause a directed, specific perturbation that can be relieved via a specific adaptation to disarm the perturbation, while non-metabolic osmolytes will cause a more general stress response that can be mitigated via a wide variety of adaptations that generally enhance growth across osmolarities. This study highlights the utility of experimental evolution for dissecting complex cellular networks and environmental interactions.

Type of resource	text
Date created	April 24, 2015

Author	Anjur-Dietrich, Maya
Advisor	Huang, Kerwyn Casey
Degree granting institution	Stanford University. Department of Bioengineering.

Location	https://purl.stanford.edu/tr670nb0975

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License: This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

Preferred Citation: Anjur-Dietrich, Maya, and Huang, Kerwyn Casey. (2015). Experimental evolution of Escherichia coli in high osmolarity environments. Stanford Digital Repository. Available at: http://purl.stanford.edu/tr670nb0975

Undergraduate Theses, School of Engineering

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