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Poly-3-hydroxybutyrate in Legionella pneumophila, an energy source for survival in low-nutrient environments

Poly-3-hydroxybutyrate in Legionella pneumophila, an energy source for survival in low-nutrient environments
Poly-3-hydroxybutyrate in Legionella pneumophila, an energy source for survival in low-nutrient environments
Chloroform-soluble material was extracted from two strains of L. pneumophila serogroup 1 following growth in continuous culture. The purified material was identified as poly-3-hydroxybutyrate (PHB) by nuclear magnetic resonance spectroscopy and by gas chromatography-mass spectrometry. PHB yields of up to 16% of cell dry weight were extracted from culture samples. The PHB was located in electron-dense intracellular inclusions, which fluoresced bright yellow when stained with the lipophilic dye Nile red. A Nile red spectrofluorometric assay provided a more accurate and reliable determination of the PHB content. PHB accumulation increased threefold during iron-limited culture and was inversely related to the concentration of iron metabolized. Chemostat-grown cells survived in a culturable state for at least 600 days when incubated at 24°C in a low-nutrient tap water environment. Nile red spectrofluorometry and flow cytometry demonstrated that PHB reserves were utilized during starvation. PHB utilization, as revealed by the decline in mean cellular fluorescence and cell complexity, correlated with loss of culturability. Fluorescence microscopy provided visual evidence of PHB utilization, with a marked reduction in the number of Nile red- stained granules during starvation. Heat shock treatment failed to resuscitate nonculturable cells. This study demonstrates that L. pneumophila accumulates significant intracellular reserves of PHB, which promote its long-term survival under conditions of starvation.
0099-2240
822-827
James, Brian W.
2982ef34-33f6-4dd1-bc54-03b0333f3339
Mauchline, W. Stuart
80ed42b2-235d-4e4b-998b-bb928a52daa2
Dennis, P. Julian
25bd2523-2802-498f-9a17-80ecea7db112
Keevil, C. William
cb7de0a7-ce33-4cfa-af52-07f99e5650eb
Wait, Robin
8a6bf555-6e67-43c7-8dab-4a759e4ea89a
James, Brian W.
2982ef34-33f6-4dd1-bc54-03b0333f3339
Mauchline, W. Stuart
80ed42b2-235d-4e4b-998b-bb928a52daa2
Dennis, P. Julian
25bd2523-2802-498f-9a17-80ecea7db112
Keevil, C. William
cb7de0a7-ce33-4cfa-af52-07f99e5650eb
Wait, Robin
8a6bf555-6e67-43c7-8dab-4a759e4ea89a

James, Brian W., Mauchline, W. Stuart, Dennis, P. Julian, Keevil, C. William and Wait, Robin (1999) Poly-3-hydroxybutyrate in Legionella pneumophila, an energy source for survival in low-nutrient environments. Applied and Environmental Microbiology, 65 (2), 822-827.

Record type: Article

Abstract

Chloroform-soluble material was extracted from two strains of L. pneumophila serogroup 1 following growth in continuous culture. The purified material was identified as poly-3-hydroxybutyrate (PHB) by nuclear magnetic resonance spectroscopy and by gas chromatography-mass spectrometry. PHB yields of up to 16% of cell dry weight were extracted from culture samples. The PHB was located in electron-dense intracellular inclusions, which fluoresced bright yellow when stained with the lipophilic dye Nile red. A Nile red spectrofluorometric assay provided a more accurate and reliable determination of the PHB content. PHB accumulation increased threefold during iron-limited culture and was inversely related to the concentration of iron metabolized. Chemostat-grown cells survived in a culturable state for at least 600 days when incubated at 24°C in a low-nutrient tap water environment. Nile red spectrofluorometry and flow cytometry demonstrated that PHB reserves were utilized during starvation. PHB utilization, as revealed by the decline in mean cellular fluorescence and cell complexity, correlated with loss of culturability. Fluorescence microscopy provided visual evidence of PHB utilization, with a marked reduction in the number of Nile red- stained granules during starvation. Heat shock treatment failed to resuscitate nonculturable cells. This study demonstrates that L. pneumophila accumulates significant intracellular reserves of PHB, which promote its long-term survival under conditions of starvation.

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More information

Accepted/In Press date: 16 November 1998
Published date: 1 February 1999

Identifiers

Local EPrints ID: 429843
URI: http://eprints.soton.ac.uk/id/eprint/429843
ISSN: 0099-2240
PURE UUID: b1eebfb5-754a-46d7-8509-c3289aa647a6
ORCID for C. William Keevil: ORCID iD orcid.org/0000-0003-1917-7706

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Date deposited: 08 Apr 2019 16:30
Last modified: 07 Oct 2020 08:30

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Contributors

Author: Brian W. James
Author: W. Stuart Mauchline
Author: P. Julian Dennis
Author: Robin Wait

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