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Single-Cell Analysis of the Physiology of Mechanosensation in Bacteria


Bialecka-Fornal, Maja I. (2013) Single-Cell Analysis of the Physiology of Mechanosensation in Bacteria. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/7SRD-WS94.


Escherichia coli is one of the best studied living organisms and a model system for many biophysical investigations. Despite countless discoveries of the details of its physiology, we still lack a holistic understanding of how these bacteria react to changes in their environment. One of the most important examples is their response to osmotic shock. One of the mechanistic elements protecting cell integrity upon exposure to sudden changes of osmolarity is the presence of mechanosensitive channels in the cell membrane. These channels are believed to act as tension release valves protecting the inner membrane from rupturing. This thesis presents an experimental study of various aspects of mechanosensation in bacteria. We examine cell survival after osmotic shock and how the number of MscL (Mechanosensitive channel of Large conductance) channels expressed in a cell influences its physiology. We developed an assay that allows real-time monitoring of the rate of the osmotic challenge and direct observation of cell morphology during and after the exposure to osmolarity change. The work described in this thesis introduces tools that can be used to quantitatively determine at the single-cell level the number of expressed proteins (in this case MscL channels) as a function of, e.g., growth conditions. The improvement in our quantitative description of mechanosensation in bacteria allows us to address many, so far unsolved, problems, like the minimal number of channels needed for survival, and can begin to paint a clearer picture of why there are so many distinct types of mechanosensitive channels.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:mechanosensitive channels, osmotic shock, cell survival
Degree Grantor:California Institute of Technology
Major Option:Biochemistry and Molecular Biophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Phillips, Robert B.
Thesis Committee:
  • Rees, Douglas C. (chair)
  • Lester, Henry A.
  • Jensen, Grant J.
  • Newman, Dianne K.
  • Phillips, Robert B.
Defense Date:29 April 2013
Funding AgencyGrant Number
National Institutes of HealthR01 GM084211
Record Number:CaltechTHESIS:05142013-213725125
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7710
Deposited By: Maja Bialecka-Fornal
Deposited On:17 May 2013 22:53
Last Modified:08 Nov 2023 00:41

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