Species differences in accumulation of nitrogen pools in phytoplankton

Dortch, Quay; Clayton, John R.; Thoresen, Steven S.; Ahmed, S. I.

doi:10.1007/bf00393218

Cited by 283 publications

(230 citation statements)

References 42 publications

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“…Our transcriptomic identification of a putative family of vacuolar transporters reinforces data from marine environments that indicate diatoms have high maximum nutrient uptake rates and storage capabilities (i.e., luxury uptake) relative to rates of immediate assimilation (Dortch et al, 1984;Lomas and Glibert, 2000;Villareal et al, 1993). This ecologically advantageous physiological trait of diatoms under nonequilibrium conditions in the marine environment (Cermeño et al, 2011) may rely, in part, on the capacity of vacuolar transporters to respond quickly to elevated NO 3 2 , as we have observed here in the 1-h response by NR-KO14 cells ( Figures 8A and 8B).…”

Section: Vacuolar No 3 2 Transport and Storagesupporting

confidence: 76%

Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

et al. 2017

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Section: Vacuolar No 3 2 Transport and Storagesupporting

confidence: 76%

Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

et al. 2017

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“…Concerning Thalassiosira, the practically linear relationship between uptake and nitrate concentration (Figure 4, 30 November sample) is very similar to that shown by the same genus in culture (Collos et al, 1992) at a similar growth rate (0·89 day 1 vs. 0·82 day 1 in the present case). The lack of saturation at high nitrate levels for these two diatoms can also be related to their ability to accumulate large internal nitrate pools, in contrast to Chaetoceros (Dortch et al, 1984). Diffusion-controlled kinetics are unlikely here as internal nitrate concentrations are generally in the millimolar range in phytoplankton (Dortch et al, 1984;Marsot et al, 1992).…”

Section: Discussionmentioning

confidence: 97%

“…The lack of saturation at high nitrate levels for these two diatoms can also be related to their ability to accumulate large internal nitrate pools, in contrast to Chaetoceros (Dortch et al, 1984). Diffusion-controlled kinetics are unlikely here as internal nitrate concentrations are generally in the millimolar range in phytoplankton (Dortch et al, 1984;Marsot et al, 1992).…”

Section: Discussionmentioning

confidence: 97%

Variability in Nitrate Uptake Kinetics of Phytoplankton Communities in a Mediterranean Coastal Lagoon

Collos

Vaquer

Bibent

et al. 1997

Estuarine, Coastal and Shelf Science

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Nitrate uptake kinetics of different phytoplankton communities exhibit great variability over a 1-year period. Classical saturation kinetics accompanied by an induction phase are shown by blooms of Chaetoceros sp. in low nitrate waters. Biphasic kinetics, with transition points between 10 and 50 M, are shown by blooms of Skeletonema costatum and flagellates, while unsaturated kinetics (up to 100 M) are shown by Thalassiosira blooms and flagellate blooms. The latter also exhibit surge uptake of nitrate in situations of negative growth rates and rather high ammonium levels. The uptake patterns of the three diatom genera are similar to those observed in cultures or consistent with known internal nitrate accumulation characteristics. Based on the kinetic patterns presented, it is apparent that, for nitrate concentrations near 50 M such as in upwelling areas, nitrate uptake will be underestimated in present models of nitrate assimilation by a factor of almost 2 for S. costatum and a factor of about 3 for Thalassiosira sp. Academic Press Limited

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“…This may relate to the functional differences of nitrate between the two groups and/or to nitrate's relative availability in their respective environments. Cells that assimilate nitrate likely expend substantial energy to mitigate its loss, given a steep concentration gradient between the cells' interior and the environment (Dortch et al 1984). In contrast, denitrifiers may forego the energetic expense of minimizing nitrate leakage in environments in which nitrate is abundant, and the effort to acquire nitrate at very low concentrations may be minimal given the relatively high demand for nitrate associated with anaerobic respiration.…”

Section: Discussionmentioning

confidence: 99%

Nitrogen and oxygen isotope fractionation during dissimilatory nitrate reduction by denitrifying bacteria

Granger

Sigman

Lehmann

et al. 2008

Limnology & Oceanography

378

449

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We report the first measurements of coupled nitrogen (N) and oxygen (O) isotope fractionation of nitrate by laboratory cultures of denitrifying bacteria. Two seawater strains (Pseudomonas stutzeri, Ochrobactrum sp.) and three freshwater strains (Paracoccus denitrificans, Pseudomonas chlororaphis, Rhodobacter sphaeroides) were examined. Among four strains of facultative anaerobic denitrifiers, N and O isotope effects were variable, ranging from 5% to 25%, with evidence for a drop in the isotope effects as nitrate concentrations approached the halfsaturation constant for nitrate transport. O isotope effects were similar to their corresponding N isotope effect, such that the progressive increase in 1] 3 1000), yielded slopes of 0.86 to 1.02, with a mean value of 0.96. R. sphaeroides, a photo-heterotroph that possesses only a periplasmic (nonrespiring) dissimilatory nitrate reductase, showed less variability in nitrate N isotope effects, between 13% and 20%, with a modal value of ,15%. In contrast to the respiratory denitrifiers, R. sphaeroides consistently showed a distinct ratio of d 18 O to d 15 N change of ,0.62. We hypothesize that heavy N and O isotope discrimination during respiratory denitrification occurs during the intracellular reduction of nitrate by the respiratory nitrate reductase, and the observed magnitude of fractionation is likely regulated by the ratio of cellular nitrate efflux relative to uptake. The data for R. sphaeroides are consistent with isotope discrimination directly reflecting the N and O isotope effects of the periplasmic nitrate reductase NAP, without modification by nitrate uptake and efflux.

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Species differences in accumulation of nitrogen pools in phytoplankton

Cited by 283 publications

References 42 publications

Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

Variability in Nitrate Uptake Kinetics of Phytoplankton Communities in a Mediterranean Coastal Lagoon

Nitrogen and oxygen isotope fractionation during dissimilatory nitrate reduction by denitrifying bacteria

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