Regulation of nif gene expression and the energetics of N 2 fixation over the diel cycle in a hot spring microbial mat

Steunou, AS; Jensen, SI; Brecht, E; Becraft, ED; Bateson, MM; Kilian, O; Bhaya, D; Ward, DM; Peters, JW; Grossman, AR; Kühl, M

Regulation of nif gene expression and the energetics of N 2 fixation over the diel cycle in a hot spring microbial mat

Steunou, AS Jensen, SI Brecht, E Becraft, ED Bateson, MM Kilian, O Bhaya, D Ward, DM Peters, JW Grossman, AR Kühl, M

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Publication Type:: Journal Article
Citation:: ISME Journal, 2008, 2 (4), pp. 364 - 378
Issue Date:: 2008-04-01

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Field	Value	Language
dc.contributor.author	Steunou, AS	en_US
dc.contributor.author	Jensen, SI	en_US
dc.contributor.author	Brecht, E	en_US
dc.contributor.author	Becraft, ED	en_US
dc.contributor.author	Bateson, MM	en_US
dc.contributor.author	Kilian, O	en_US
dc.contributor.author	Bhaya, D	en_US
dc.contributor.author	Ward, DM	en_US
dc.contributor.author	Peters, JW	en_US
dc.contributor.author	Grossman, AR	en_US
dc.contributor.author	Kühl, M https://orcid.org/0000-0002-1792-4790	en_US
dc.date.issued	2008-04-01	en_US
dc.identifier.citation	ISME Journal, 2008, 2 (4), pp. 364 - 378	en_US
dc.identifier.issn	1751-7362	en_US
dc.identifier.uri	http://hdl.handle.net/10453/15468
dc.description.abstract	Nitrogen fixation, a prokaryotic, O 2 -inhibited process that reduces N 2 gas to biomass, is of paramount importance in biogeochemical cycling of nitrogen. We analyzed the levels of nif transcripts of Synechococcus ecotypes, NifH subunit and nitrogenase activity over the diel cycle in the microbial mat of an alkaline hot spring in Yellowstone National Park. The results showed a rise in nif transcripts in the evening, with a subsequent decline over the course of the night. In contrast, immunological data demonstrated that the level of the NifH polypeptide remained stable during the night, and only declined when the mat became oxic in the morning. Nitrogenase activity was low throughout the night; however, it exhibited two peaks, a small one in the evening and a large one in the early morning, when light began to stimulate cyanobacterial photosynthetic activity, but O 2 consumption by respiration still exceeded the rate of O 2 evolution. Once the irradiance increased to the point at which the mat became oxic, the nitrogenase activity was strongly inhibited. Transcripts for proteins associated with energy-producing metabolisms in the cell also followed diel patterns, with fermentation-related transcripts accumulating at night, photosynthesis- and respiration-related transcripts accumulating during the day and late afternoon, respectively. These results are discussed with respect to the energetics and regulation of N 2 fixation in hot spring mats and factors that can markedly influence the extent of N 2 fixation over the diel cycle. © 2008 International Society for Microbial Ecology All rights reserved.	en_US
dc.relation.ispartof	ISME Journal	en_US
dc.relation.isbasedon	10.1038/ismej.2007.117	en_US
dc.subject.classification	Microbiology	en_US
dc.subject.mesh	Synechococcus	en_US
dc.subject.mesh	Oxidoreductases	en_US
dc.subject.mesh	Bacterial Proteins	en_US
dc.subject.mesh	Reverse Transcriptase Polymerase Chain Reaction	en_US
dc.subject.mesh	Ecosystem	en_US
dc.subject.mesh	Hot Springs	en_US
dc.subject.mesh	Nitrogen Fixation	en_US
dc.subject.mesh	Photosynthesis	en_US
dc.subject.mesh	Transcription, Genetic	en_US
dc.subject.mesh	Gene Expression Regulation, Bacterial	en_US
dc.subject.mesh	Energy Metabolism	en_US
dc.subject.mesh	Oxygen Consumption	en_US
dc.subject.mesh	Light	en_US
dc.subject.mesh	Darkness	en_US
dc.title	Regulation of nif gene expression and the energetics of N 2 fixation over the diel cycle in a hot spring microbial mat	en_US
dc.type	Journal Article
utslib.citation.volume	4	en_US
utslib.citation.volume	2	en_US
utslib.for	1002 Environmental Biotechnology	en_US
utslib.for	05 Environmental Sciences	en_US
utslib.for	06 Biological Sciences	en_US
utslib.for	10 Technology	en_US
dc.location.activity	Pittsburgh, USA
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
utslib.copyright.status	closed_access
pubs.issue	4	en_US
pubs.publication-status	Published	en_US
pubs.volume	2	en_US

Abstract:

Nitrogen fixation, a prokaryotic, O 2 -inhibited process that reduces N 2 gas to biomass, is of paramount importance in biogeochemical cycling of nitrogen. We analyzed the levels of nif transcripts of Synechococcus ecotypes, NifH subunit and nitrogenase activity over the diel cycle in the microbial mat of an alkaline hot spring in Yellowstone National Park. The results showed a rise in nif transcripts in the evening, with a subsequent decline over the course of the night. In contrast, immunological data demonstrated that the level of the NifH polypeptide remained stable during the night, and only declined when the mat became oxic in the morning. Nitrogenase activity was low throughout the night; however, it exhibited two peaks, a small one in the evening and a large one in the early morning, when light began to stimulate cyanobacterial photosynthetic activity, but O 2 consumption by respiration still exceeded the rate of O 2 evolution. Once the irradiance increased to the point at which the mat became oxic, the nitrogenase activity was strongly inhibited. Transcripts for proteins associated with energy-producing metabolisms in the cell also followed diel patterns, with fermentation-related transcripts accumulating at night, photosynthesis- and respiration-related transcripts accumulating during the day and late afternoon, respectively. These results are discussed with respect to the energetics and regulation of N 2 fixation in hot spring mats and factors that can markedly influence the extent of N 2 fixation over the diel cycle. © 2008 International Society for Microbial Ecology All rights reserved.

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http://hdl.handle.net/10453/15468