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Quantitative flow cytometry to understand population heterogeneity in response to changes in substrate availability in escherichia coli and saccharomyces cerevisiae chemostats

Heins, Anna Lena; Johanson, Ted LU ; Han, Shanshan; Lundin, Luisa; Carlquist, Magnus LU ; Gernaey, Krist V.; Sørensen, Søren J. and Lantz, Anna Eliasson (2019) In Frontiers in Bioengineering and Biotechnology 7(AUG).
Abstract

Microbial cells in bioprocesses are usually described with averaged parameters. But in fact, single cells within populations vary greatly in characteristics such as stress resistance, especially in response to carbon source gradients. Our aim was to introduce tools to quantify population heterogeneity in bioprocesses using a combination of reporter strains, flow cytometry, and easily comprehensible parameters. We calculated mean, mode, peak width, and coefficient of variance to describe distribution characteristics and temporal shifts in fluorescence intensity. The skewness and the slope of cumulative distribution function plots illustrated differences in distribution shape. These parameters are person-independent and precise. We... (More)

Microbial cells in bioprocesses are usually described with averaged parameters. But in fact, single cells within populations vary greatly in characteristics such as stress resistance, especially in response to carbon source gradients. Our aim was to introduce tools to quantify population heterogeneity in bioprocesses using a combination of reporter strains, flow cytometry, and easily comprehensible parameters. We calculated mean, mode, peak width, and coefficient of variance to describe distribution characteristics and temporal shifts in fluorescence intensity. The skewness and the slope of cumulative distribution function plots illustrated differences in distribution shape. These parameters are person-independent and precise. We demonstrated this by quantifying growth-related population heterogeneity of Saccharomyces cerevisiae and Escherichia coli reporter strains in steady-state of aerobic glucose-limited chemostat cultures at different dilution rates and in response to glucose pulses. Generally, slow-growing cells showed stronger responses to glucose excess than fast-growing cells. Cell robustness, measured as membrane integrity after exposure to freeze-thaw treatment, of fast-growing cells was strongly affected in subpopulations of low membrane robustness. Glucose pulses protected subpopulations of fast-growing but not slower-growing yeast cells against membrane damage. Our parameters could successfully describe population heterogeneity, thereby revealing physiological characteristics that might have been overlooked during traditional averaged analysis.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Flow cytometry, Glucose pulse, Membrane robustness, Population heterogeneity, Quantitative flow cytometry, Reporter strain
in
Frontiers in Bioengineering and Biotechnology
volume
7
issue
AUG
publisher
Frontiers Media S. A.
external identifiers
  • scopus:85071727214
DOI
10.3389/fbioe.2019.00187
language
English
LU publication?
yes
id
2a34423b-b405-427c-bdf7-7f10bfca7039
date added to LUP
2019-09-23 11:14:40
date last changed
2019-10-08 03:58:54
@article{2a34423b-b405-427c-bdf7-7f10bfca7039,
  abstract     = {<p>Microbial cells in bioprocesses are usually described with averaged parameters. But in fact, single cells within populations vary greatly in characteristics such as stress resistance, especially in response to carbon source gradients. Our aim was to introduce tools to quantify population heterogeneity in bioprocesses using a combination of reporter strains, flow cytometry, and easily comprehensible parameters. We calculated mean, mode, peak width, and coefficient of variance to describe distribution characteristics and temporal shifts in fluorescence intensity. The skewness and the slope of cumulative distribution function plots illustrated differences in distribution shape. These parameters are person-independent and precise. We demonstrated this by quantifying growth-related population heterogeneity of Saccharomyces cerevisiae and Escherichia coli reporter strains in steady-state of aerobic glucose-limited chemostat cultures at different dilution rates and in response to glucose pulses. Generally, slow-growing cells showed stronger responses to glucose excess than fast-growing cells. Cell robustness, measured as membrane integrity after exposure to freeze-thaw treatment, of fast-growing cells was strongly affected in subpopulations of low membrane robustness. Glucose pulses protected subpopulations of fast-growing but not slower-growing yeast cells against membrane damage. Our parameters could successfully describe population heterogeneity, thereby revealing physiological characteristics that might have been overlooked during traditional averaged analysis.</p>},
  articleno    = {187},
  author       = {Heins, Anna Lena and Johanson, Ted and Han, Shanshan and Lundin, Luisa and Carlquist, Magnus and Gernaey, Krist V. and Sørensen, Søren J. and Lantz, Anna Eliasson},
  keyword      = {Flow cytometry,Glucose pulse,Membrane robustness,Population heterogeneity,Quantitative flow cytometry,Reporter strain},
  language     = {eng},
  number       = {AUG},
  publisher    = {Frontiers Media S. A.},
  series       = {Frontiers in Bioengineering and Biotechnology},
  title        = {Quantitative flow cytometry to understand population heterogeneity in response to changes in substrate availability in escherichia coli and saccharomyces cerevisiae chemostats},
  url          = {http://dx.doi.org/10.3389/fbioe.2019.00187},
  volume       = {7},
  year         = {2019},
}