Impact of acetate, pyruvate, and physiological state on respiration and respiratory quotients in Pseudomonas nautica

Roy, Sylvie; Packard, Ted T; Berdalet, Elisa; St-Amand, L

doi:10.3354/ame017105

Cited by 12 publications

(5 citation statements)

References 14 publications

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“…In slow filtration columns, the first cm of sediment which exhibited the highest removal rates of BDOC and DO also had a distinctively higher SOC concentration. SOC accumulation within this uppermost layer probably reflected a biological retention and/or assimilation of BDOC rather than a physical adsorption of BDOC onto mineral particles because our C to O 2 molar ratio of 0.65 effectively corresponded to values reported in the literature for microbial degradation of BDOC (Bauerfind 1985;Pusch and Schwoerbel 1994;Roy et al 1999). Baker et al (1999) did not observe any acetate sorption onto aquifer sediment samples of Rio Calaveras that were incubated for 30 min in acetate solutions with concentrations ranging from 1 to 100 mg C l -1 .…”

Section: Effect Of Doc Supply On Srsupporting

confidence: 56%

Vertical change in dissolved organic carbon and oxygen at the water table region of an aquifer recharged with stormwater: biological uptake or mixing?

et al. 2009

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Decreases in dissolved organic carbon (DOC) and dissolved oxygen (DO) with increasing depth below the groundwater table are often considered as evidence for aerobic respiration; however, they may reflect mixing of infiltrating water and groundwater. We found that groundwater DOC concentration was on average 0.3 mg C l -1 higher and DO concentration 1.5 mg O 2 l -1 lower at recharge sites replenished with stormwater than at reference sites fed by direct infiltration of rain water from the land surface. Groundwater DOC increased and DO decreased with increasing vadose zone thickness (VZT) at both recharge and reference sites. There was no significant interaction between the effects of stormwater infiltration and VZT. Vertical changes in DOC and DO below the groundwater table at recharge sites could account for by simple mixing of infiltrating stormwater and groundwater. Moreover, aquifer sediment respiration (SR) was not significantly higher at recharge sites than at reference sites. However, slow filtration column experiments showed that SR increased significantly with an increasing supply of easily biodegradable DOC. We conclude that the observed reduction in DOC below the groundwater table at recharge sites was essentially due to water mixing rather than biological uptake because of the low biodegradability of the DOC and the short transit time of stormwater in the upper layers of groundwater. Our results highlight the need to distinguish between the effect of hydrological and biological processes on DOC and DO patterns below the groundwater before conclusions are made on the efficiency of groundwater in degrading surface-derived DOC.

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Section: Effect Of Doc Supply On Srsupporting

confidence: 56%

Vertical change in dissolved organic carbon and oxygen at the water table region of an aquifer recharged with stormwater: biological uptake or mixing?

et al. 2009

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“…Respiratory enzyme activities (IDH and ETS) have been shown to increase during the exponential growth phase and to plateau at the end of this phase in marine bacterial cultures grown on different carbon sources (2,34,35,40). During C starvation, these enzymes were not cannibalized to fill other needs of the cells.…”

Section: Discussionmentioning

confidence: 99%

NADP-Isocitrate Dehydrogenase from Pseudomonas nautica : Kinetic Constant Determination and Carbon Limitation Effects on the Pool of Intracellular Substrates

Roy

Packard

1998

Appl Environ Microbiol

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Variations of intracellular concentrations of isocitrate and NADP+ were measured throughout all growth phases of the marine bacterium Pseudomonas nautica. The intracellular isocitrate concentration tracked the intracellular protein concentration throughout all phases of growth. It rapidly increased in early exponential phase to a maximum and fell to nearly zero in parallel with pyruvate exhaustion in the culture medium. The intracellular NADP+ and protein concentrations increased in parallel during the exponential phase but were poorly correlated. Even after carbon exhaustion, the intracellular NADP+concentration stayed high, as did protein levels. The results demonstrated that the intracellular isocitrate concentration, but not the intracellular NADP+ concentration, was affected by the carbon availability in the culture. They also suggest that, because of its variability, isocitrate, but not NADP+, plays the larger role in the control of the respiratory CO2production rate (R CO2 ). From initial rate studies, bisubstrate Michaelis constants and the dissociation constant were determined for NADP+-specific isocitrate dehydrogenase (IDH) from P. nautica. These studies support the hypothesis that the mechanism of IDH’s activity involves the ordered addition of the substrates,d-isocitrate and NADP+. Furthermore, the results support the use of a bisubstrate enzyme kinetic equation to model R CO2 in P. nautica.

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“…Quantifying the variability in RQ allows not only the production of CO 2 to be calculated from dissolved oxygen consumption, but also reveals shifts in plankton physiology that are not evident from any other measurement. Culture studies with marine bacteria (Vibrio natriegens and Pseudomonas nautica) show that the respiratory quotient varies with physiological state, metabolic pathway and carbon source (acetate or pyruvate) (Berdalet et al, 1995;Roy et al, 1999;Romero-Kutzner et al, 2015).…”

Section: Respiratory Quotientsmentioning

confidence: 99%

Microbial Respiration, the Engine of Ocean Deoxygenation

Robinson

2019

Front. Mar. Sci.

109

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Microbial plankton respiration is the key determinant in the balance between the storage of organic carbon in the oceans or its conversion to carbon dioxide with accompanying consumption of dissolved oxygen. Over the past 50 years, dissolved oxygen concentrations have decreased in many parts of the world's oceans, and this trend of ocean deoxygenation is predicted to continue. Yet despite its pivotal role in ocean deoxygenation, microbial respiration remains one of the least constrained microbial metabolic processes. Improved understanding of the magnitude and variability of respiration, including attribution to component plankton groups, and quantification of the respiratory quotient, would enable better predictions, and projections of the intensity and extent of ocean deoxygenation and of the integrative impact of ocean deoxygenation, ocean acidification, warming, and changes in nutrient concentration and stoichiometry on marine carbon storage. This study will synthesize current knowledge of respiration in relation to deoxygenation, including the drivers of its variability, identify key unknowns in our ability to project future scenarios and suggest an approach to move the field forward.

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Impact of acetate, pyruvate, and physiological state on respiration and respiratory quotients in Pseudomonas nautica

Cited by 12 publications

References 14 publications

Vertical change in dissolved organic carbon and oxygen at the water table region of an aquifer recharged with stormwater: biological uptake or mixing?

Vertical change in dissolved organic carbon and oxygen at the water table region of an aquifer recharged with stormwater: biological uptake or mixing?

NADP-Isocitrate Dehydrogenase from Pseudomonas nautica : Kinetic Constant Determination and Carbon Limitation Effects on the Pool of Intracellular Substrates

Microbial Respiration, the Engine of Ocean Deoxygenation

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