Adaptation to UVA radiation of E. coli growing in continuous culture

Michael Berney, Hans Ulrich Weilenmann, Thomas Egli

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Adaptive responses of bacteria to physical or chemical stresses in the laboratory or in the environment are of great interest. Here we investigated the ability of Escherichia coli growing in continuous culture to adapt to UVA radiation. It was shown that E. coli indeed expressed an adaptive response to UVA irradiation at an intensity of 50 W/m2. Cells grown in continuous culture with complex medium (diluted Luria Bertani broth) at dilution rates of 0.7 h-1, 0.5 h-1 and 0.3 h-1 were able to maintain growth under UVA irradiation after a transient reduction of specific growth rate and recovery. In contrast, slow-growing cells (D = 0.05 h-1) were unable to induce enough protection capacity to maintain growth under UVA irradiation. We propose that faster growing E. coli cells have a higher adaptive flexibility to UVA light-stress than slow-growing cells. Furthermore it was shown with flow cytometry and viability stains that at a dilution rate of 0.3 h-1 only a small fraction (≤1%) of the initial cell population survived UVA light-stress. Adapted cells were significantly larger (30%) than unstressed cells and had a lower growth yield. Furthermore, efflux pump activity was diminished in adapted cells. In a second irradiation period (after omitting UVA irradiation for 70 h) adapted cells were able to trigger the adaptive response twice as fast. Additionally, this study shows that continuous cultivation with direct stress application allows reproducible investigation of the physiological and possibly also molecular mechanisms during adaptation of E. coli populations to UVA light.

Original languageEnglish (US)
Pages (from-to)149-159
Number of pages11
JournalJournal of Photochemistry and Photobiology B: Biology
Volume86
Issue number2
DOIs
StatePublished - Feb 1 2007
Externally publishedYes

Fingerprint

Escherichia coli
Irradiation
Radiation
radiation
cells
irradiation
Dilution
Cells
dilution
Flow cytometry
Growth
Light
broths
Cell culture
efflux
cytometry
Bacteria
Coloring Agents
Escherichia
Pumps

Keywords

  • Adaptation
  • Continuous culture
  • E. coli
  • Resistance
  • Solar disinfection (SODIS)
  • UVA light

ASJC Scopus subject areas

  • Plant Science
  • Bioengineering
  • Physical and Theoretical Chemistry

Cite this

Adaptation to UVA radiation of E. coli growing in continuous culture. / Berney, Michael; Weilenmann, Hans Ulrich; Egli, Thomas.

In: Journal of Photochemistry and Photobiology B: Biology, Vol. 86, No. 2, 01.02.2007, p. 149-159.

Research output: Contribution to journalArticle

@article{094d90ad77494258b999889924282b16,
title = "Adaptation to UVA radiation of E. coli growing in continuous culture",
abstract = "Adaptive responses of bacteria to physical or chemical stresses in the laboratory or in the environment are of great interest. Here we investigated the ability of Escherichia coli growing in continuous culture to adapt to UVA radiation. It was shown that E. coli indeed expressed an adaptive response to UVA irradiation at an intensity of 50 W/m2. Cells grown in continuous culture with complex medium (diluted Luria Bertani broth) at dilution rates of 0.7 h-1, 0.5 h-1 and 0.3 h-1 were able to maintain growth under UVA irradiation after a transient reduction of specific growth rate and recovery. In contrast, slow-growing cells (D = 0.05 h-1) were unable to induce enough protection capacity to maintain growth under UVA irradiation. We propose that faster growing E. coli cells have a higher adaptive flexibility to UVA light-stress than slow-growing cells. Furthermore it was shown with flow cytometry and viability stains that at a dilution rate of 0.3 h-1 only a small fraction (≤1{\%}) of the initial cell population survived UVA light-stress. Adapted cells were significantly larger (30{\%}) than unstressed cells and had a lower growth yield. Furthermore, efflux pump activity was diminished in adapted cells. In a second irradiation period (after omitting UVA irradiation for 70 h) adapted cells were able to trigger the adaptive response twice as fast. Additionally, this study shows that continuous cultivation with direct stress application allows reproducible investigation of the physiological and possibly also molecular mechanisms during adaptation of E. coli populations to UVA light.",
keywords = "Adaptation, Continuous culture, E. coli, Resistance, Solar disinfection (SODIS), UVA light",
author = "Michael Berney and Weilenmann, {Hans Ulrich} and Thomas Egli",
year = "2007",
month = "2",
day = "1",
doi = "10.1016/j.jphotobiol.2006.08.014",
language = "English (US)",
volume = "86",
pages = "149--159",
journal = "Journal of Photochemistry and Photobiology B: Biology",
issn = "1011-1344",
publisher = "Elsevier",
number = "2",

}

TY - JOUR

T1 - Adaptation to UVA radiation of E. coli growing in continuous culture

AU - Berney, Michael

AU - Weilenmann, Hans Ulrich

AU - Egli, Thomas

PY - 2007/2/1

Y1 - 2007/2/1

N2 - Adaptive responses of bacteria to physical or chemical stresses in the laboratory or in the environment are of great interest. Here we investigated the ability of Escherichia coli growing in continuous culture to adapt to UVA radiation. It was shown that E. coli indeed expressed an adaptive response to UVA irradiation at an intensity of 50 W/m2. Cells grown in continuous culture with complex medium (diluted Luria Bertani broth) at dilution rates of 0.7 h-1, 0.5 h-1 and 0.3 h-1 were able to maintain growth under UVA irradiation after a transient reduction of specific growth rate and recovery. In contrast, slow-growing cells (D = 0.05 h-1) were unable to induce enough protection capacity to maintain growth under UVA irradiation. We propose that faster growing E. coli cells have a higher adaptive flexibility to UVA light-stress than slow-growing cells. Furthermore it was shown with flow cytometry and viability stains that at a dilution rate of 0.3 h-1 only a small fraction (≤1%) of the initial cell population survived UVA light-stress. Adapted cells were significantly larger (30%) than unstressed cells and had a lower growth yield. Furthermore, efflux pump activity was diminished in adapted cells. In a second irradiation period (after omitting UVA irradiation for 70 h) adapted cells were able to trigger the adaptive response twice as fast. Additionally, this study shows that continuous cultivation with direct stress application allows reproducible investigation of the physiological and possibly also molecular mechanisms during adaptation of E. coli populations to UVA light.

AB - Adaptive responses of bacteria to physical or chemical stresses in the laboratory or in the environment are of great interest. Here we investigated the ability of Escherichia coli growing in continuous culture to adapt to UVA radiation. It was shown that E. coli indeed expressed an adaptive response to UVA irradiation at an intensity of 50 W/m2. Cells grown in continuous culture with complex medium (diluted Luria Bertani broth) at dilution rates of 0.7 h-1, 0.5 h-1 and 0.3 h-1 were able to maintain growth under UVA irradiation after a transient reduction of specific growth rate and recovery. In contrast, slow-growing cells (D = 0.05 h-1) were unable to induce enough protection capacity to maintain growth under UVA irradiation. We propose that faster growing E. coli cells have a higher adaptive flexibility to UVA light-stress than slow-growing cells. Furthermore it was shown with flow cytometry and viability stains that at a dilution rate of 0.3 h-1 only a small fraction (≤1%) of the initial cell population survived UVA light-stress. Adapted cells were significantly larger (30%) than unstressed cells and had a lower growth yield. Furthermore, efflux pump activity was diminished in adapted cells. In a second irradiation period (after omitting UVA irradiation for 70 h) adapted cells were able to trigger the adaptive response twice as fast. Additionally, this study shows that continuous cultivation with direct stress application allows reproducible investigation of the physiological and possibly also molecular mechanisms during adaptation of E. coli populations to UVA light.

KW - Adaptation

KW - Continuous culture

KW - E. coli

KW - Resistance

KW - Solar disinfection (SODIS)

KW - UVA light

UR - http://www.scopus.com/inward/record.url?scp=33845575771&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33845575771&partnerID=8YFLogxK

U2 - 10.1016/j.jphotobiol.2006.08.014

DO - 10.1016/j.jphotobiol.2006.08.014

M3 - Article

C2 - 17055285

AN - SCOPUS:33845575771

VL - 86

SP - 149

EP - 159

JO - Journal of Photochemistry and Photobiology B: Biology

JF - Journal of Photochemistry and Photobiology B: Biology

SN - 1011-1344

IS - 2

ER -