Nitrate respiration occurs throughout the depth of mucoid and non-mucoid: Pseudomonas aeruginosa submerged agar colony biofilms including the oxic zone.
Nitrate respiration occurs throughout the depth of mucoid and non-mucoid: Pseudomonas aeruginosa submerged agar colony biofilms including the oxic zone.
Pseudomonas aeruginosa is an opportunistic pathogen and well characterized biofilm former. P. aeruginosa forms strong oxygen gradients inside biofilms due to rapid oxygen respiration in the top layers and the poor solubility of oxygen coupled with diffusion limited transport. Transcriptomic evidence from in vitro and ex vivo sampling suggests that denitrification is occurring in biofilms in ostensibly oxic environments. It is hypothesized that in the presence of nitrate there is stratification with aerobic respiration occurring in the outer oxic layer and denitrification in the lower anoxic zone. We used submerged agar colony biofilms grown from mucoid (FRD1) and non-mucoid (PAO1) strains to simultaneously measure depth microprofiles of oxygen and nitrous oxide in the same colony with microelectrodes. Oxygen respiration occurred at the top of the colony as expected but denitrification occurred throughout the entire depth, even in the oxic region. Local denitrification rates were highly variable suggesting heterogenous metabolic activity within the colony. We also assessed the short-term influence of tobramycin on aerobic respiration within a PAO1 colony. Although there was an immediate reduction in respiration it was never completely arrested over a 2 h period. On tobramycin removal the oxygen gradient steadily reestablished, demonstrating immediate recovery of metabolic activity.
Schwermer, Carsten U.
b4affdc8-2b07-4c11-9698-c1280243e498
Debeer, Dirk
fc1a7a0a-613d-4a5c-af1a-09d03f4a58b4
Stoodley, Paul
08614665-92a9-4466-806e-20c6daeb483f
20 May 2022
Schwermer, Carsten U.
b4affdc8-2b07-4c11-9698-c1280243e498
Debeer, Dirk
fc1a7a0a-613d-4a5c-af1a-09d03f4a58b4
Stoodley, Paul
08614665-92a9-4466-806e-20c6daeb483f
Schwermer, Carsten U., Debeer, Dirk and Stoodley, Paul
(2022)
Nitrate respiration occurs throughout the depth of mucoid and non-mucoid: Pseudomonas aeruginosa submerged agar colony biofilms including the oxic zone.
Scientific Reports, 12 (8557), [8557].
(doi:10.1038/s41598-022-11957-4).
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen and well characterized biofilm former. P. aeruginosa forms strong oxygen gradients inside biofilms due to rapid oxygen respiration in the top layers and the poor solubility of oxygen coupled with diffusion limited transport. Transcriptomic evidence from in vitro and ex vivo sampling suggests that denitrification is occurring in biofilms in ostensibly oxic environments. It is hypothesized that in the presence of nitrate there is stratification with aerobic respiration occurring in the outer oxic layer and denitrification in the lower anoxic zone. We used submerged agar colony biofilms grown from mucoid (FRD1) and non-mucoid (PAO1) strains to simultaneously measure depth microprofiles of oxygen and nitrous oxide in the same colony with microelectrodes. Oxygen respiration occurred at the top of the colony as expected but denitrification occurred throughout the entire depth, even in the oxic region. Local denitrification rates were highly variable suggesting heterogenous metabolic activity within the colony. We also assessed the short-term influence of tobramycin on aerobic respiration within a PAO1 colony. Although there was an immediate reduction in respiration it was never completely arrested over a 2 h period. On tobramycin removal the oxygen gradient steadily reestablished, demonstrating immediate recovery of metabolic activity.
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Accepted/In Press date: 19 April 2022
Published date: 20 May 2022
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This work was originally inspired by the findings of Dr. Dan Hassett, Professor at the University of Cincinnati. Dan died unexpectedly Thursday, April 27 and we dedicate this research to him. Thank you to Kendall Gallagher, Ohio State University for formatting.
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© 2022, The Author(s).
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Local EPrints ID: 457213
URI: http://eprints.soton.ac.uk/id/eprint/457213
ISSN: 2045-2322
PURE UUID: 45ba935b-cd2b-425d-b322-51d2df203d32
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Date deposited: 26 May 2022 16:50
Last modified: 17 Mar 2024 03:18
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Author:
Carsten U. Schwermer
Author:
Dirk Debeer
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