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Potassium stress growth characteristics and energetics in the haloarchaeon Haloarcula marismortui.

Jensen MW, Matlock SA, Reinheimer CH, Lawlor CJ, Reinheimer TA, Gorrell A - Extremophiles (2014)

Bottom Line: The presence of intracellular rubidium and cesium indicates that monovalent ion transport is important for energy production.Comparison of eight archaeal genomes indicates an increased diversity of potassium transport complex subunits in the halophilic organisms.Analysis of the generation times, intracellular concentrations and genome survey shows Har. marismortui exhibits an ability to cope with monovalent cation concentration changes in its native environment and provides insight into the organisms ion transport capability and specificity.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Northern British Columbia, 3333 University Way, Prince George, BC, V2N 4Z9, Canada.

ABSTRACT
Growth characteristics surrounding halophilic archaeal organisms are extremely limited in the scientific literature, with studies tending toward observing changes in cellular generation times under growth conditions limited to changes in temperature and sodium chloride concentrations. Currently, knowledge of the ionic stress experienced by haloarchaeal species through an excess or depletion of other required ions is lacking at best. The halophilic archaeon, Haloarcula marismortui, was analyzed under extreme ionic stress conditions with a specific focus on induced potassium ion stress using growth curves and analysis of the intracellular ion concentrations. Generation times were determined under potassium chloride concentrations ranging from 8 to 720 mM, and also in the presence of the alternative monovalent cations of lithium, rubidium, and cesium under limiting potassium conditions. Intracellular ion concentrations, as determined by inductively coupled mass spectrometry (ICP-MS), indicate a minimum intracellular total ion requirement of 1.13 M while tolerating up to 2.43 M intracellular concentrations. The presence of intracellular rubidium and cesium indicates that monovalent ion transport is important for energy production. Comparison of eight archaeal genomes indicates an increased diversity of potassium transport complex subunits in the halophilic organisms. Analysis of the generation times, intracellular concentrations and genome survey shows Har. marismortui exhibits an ability to cope with monovalent cation concentration changes in its native environment and provides insight into the organisms ion transport capability and specificity.

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Generation times on different extracellular potassium concentrations. Values were obtained from the exponential growth curves via the exponential growth equation (Figure A2) vs. extracellular potassium concentration. Error bars represent standard error obtained from the determination of cellular generation times
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Fig1: Generation times on different extracellular potassium concentrations. Values were obtained from the exponential growth curves via the exponential growth equation (Figure A2) vs. extracellular potassium concentration. Error bars represent standard error obtained from the determination of cellular generation times

Mentions: Cells were grown to balanced growth in standard 23 % S.W. MGM as well as in media containing 8, 20, 220, 520, and 720 mM KCl. Each biological triplicate consisted of a technical triplicate and was monitored via spectrophotometry at 600 nm (OD600). Growth curves were constructed by measuring cell density at least once per generation time as estimated after a test culture. Measurements were averaged across all replicates and plotted against the growth time to determine the generation time (Fig. 1; Table 1).Fig. 1


Potassium stress growth characteristics and energetics in the haloarchaeon Haloarcula marismortui.

Jensen MW, Matlock SA, Reinheimer CH, Lawlor CJ, Reinheimer TA, Gorrell A - Extremophiles (2014)

Generation times on different extracellular potassium concentrations. Values were obtained from the exponential growth curves via the exponential growth equation (Figure A2) vs. extracellular potassium concentration. Error bars represent standard error obtained from the determination of cellular generation times
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4339784&req=5

Fig1: Generation times on different extracellular potassium concentrations. Values were obtained from the exponential growth curves via the exponential growth equation (Figure A2) vs. extracellular potassium concentration. Error bars represent standard error obtained from the determination of cellular generation times
Mentions: Cells were grown to balanced growth in standard 23 % S.W. MGM as well as in media containing 8, 20, 220, 520, and 720 mM KCl. Each biological triplicate consisted of a technical triplicate and was monitored via spectrophotometry at 600 nm (OD600). Growth curves were constructed by measuring cell density at least once per generation time as estimated after a test culture. Measurements were averaged across all replicates and plotted against the growth time to determine the generation time (Fig. 1; Table 1).Fig. 1

Bottom Line: The presence of intracellular rubidium and cesium indicates that monovalent ion transport is important for energy production.Comparison of eight archaeal genomes indicates an increased diversity of potassium transport complex subunits in the halophilic organisms.Analysis of the generation times, intracellular concentrations and genome survey shows Har. marismortui exhibits an ability to cope with monovalent cation concentration changes in its native environment and provides insight into the organisms ion transport capability and specificity.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Northern British Columbia, 3333 University Way, Prince George, BC, V2N 4Z9, Canada.

ABSTRACT
Growth characteristics surrounding halophilic archaeal organisms are extremely limited in the scientific literature, with studies tending toward observing changes in cellular generation times under growth conditions limited to changes in temperature and sodium chloride concentrations. Currently, knowledge of the ionic stress experienced by haloarchaeal species through an excess or depletion of other required ions is lacking at best. The halophilic archaeon, Haloarcula marismortui, was analyzed under extreme ionic stress conditions with a specific focus on induced potassium ion stress using growth curves and analysis of the intracellular ion concentrations. Generation times were determined under potassium chloride concentrations ranging from 8 to 720 mM, and also in the presence of the alternative monovalent cations of lithium, rubidium, and cesium under limiting potassium conditions. Intracellular ion concentrations, as determined by inductively coupled mass spectrometry (ICP-MS), indicate a minimum intracellular total ion requirement of 1.13 M while tolerating up to 2.43 M intracellular concentrations. The presence of intracellular rubidium and cesium indicates that monovalent ion transport is important for energy production. Comparison of eight archaeal genomes indicates an increased diversity of potassium transport complex subunits in the halophilic organisms. Analysis of the generation times, intracellular concentrations and genome survey shows Har. marismortui exhibits an ability to cope with monovalent cation concentration changes in its native environment and provides insight into the organisms ion transport capability and specificity.

Show MeSH