Nitrate Uptake and Reduction in Chlorella — Characterisation of Nitrate Uptake in Nitrate-Grown and Nitrogen-Starved Chlorella sorokiniana

Tischner, Rudolf; Lorenzen, Harald

doi:10.1007/978-3-642-67919-3_20

Cited by 14 publications

(12 citation statements)

References 14 publications

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“…This shows that the external presence of nitrate is not necessary for this increase. A similar observation was obtained for the plasmalemma-bound NR (Ward et al 1988;Tischner et al 1989) which increased without any delay. This indicates a preference for synthesis of mainly plasma-membrane NR directly after the NO;-pulses.…”

Section: Discussionsupporting

confidence: 81%

“…However, the pulses used were longer and the concentrations higher than in the experiments presented here. No data were presented concerning the expression of nitrate reductase (NR) after such pulses, although the relation between NO~ uptake and NR activity is close in algae (Tischner and Lorenzen 1981) and most higher plants (Jackson et al 1973).…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Effect of nitrate pulses on the nitrate-uptake rate, synthesis of mRNA coding for nitrate reductase, and nitrate-reductase activity in the roots of barley seedlings

Tischner

Waldeck

Goyal

et al. 1993

Planta

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Abstract. Using pulses of nitrate, instead of the permanent presence of external nitrate, to induce the nitrate-assimilating system in Hordeum vulgare L., we demonstrated that nitrate can be considered as a trigger or signal for the induction of nitrate uptake, the appearance of nitratereductase activity and the synthesis of mRNA coding for nitrate reductase. Nitrate pulses stimulated the initial rate of nitrate uptake, even after subsequent cultivation in N-free medium, and resulted in a higher acceleration of the uptake rate in the presence of nitrate than in its absence.

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Section: Discussionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 97%

Effect of nitrate pulses on the nitrate-uptake rate, synthesis of mRNA coding for nitrate reductase, and nitrate-reductase activity in the roots of barley seedlings

Tischner

Waldeck

Goyal

et al. 1993

Planta

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show abstract

“…Some experimental evidence appears incompatible with this model. In experiments with Chlorella sorokiniana 65 and P. vulgaris 9 the sensitivity of net nitrate uptake to inhibition of NH4 was much lower in N-starved plants than in Nsufficient ones which were presumably nearer to flux equilibrium. In both species sensitivity to NHt in N-starved plants increased as nitrate transport capacity was induced.…”

Section: The Role Of Ammonium Ions and Products Of Nitrogen Assimilationmentioning

confidence: 96%

Regulation of the absorption and release of nitrate by plant cells: A review of current ideas and methodology

Clarkson¹

1986

Fundamental, Ecological and Agricultural Aspects of Nitrogen Metabolism in Higher Plants

178

116

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Ms. NM 1.1 H. Lambers, J. J. Neeteson and I. Swlen (Eds.) , Fundamental, ecological and agricultural aspects of nitrogen metabolism in higher plants. ISBN Abbreviations DES -Diethylstilboestrol FCCP -Carbonyl cyanide P-trifluoromethoxy· phenylhydrazone Summary In most circumstances nitrate uptake into the cells of roots is thermodynamically uphill and the process is severely curtailed by conditions which inhibit the synthesis of A TP and protein. The activity of the transport system can be augmented 2 to S-fold from a constitutive level to an induced level, by the provision of nitrate in the external solutiun to cells which have not previously received a nitrate supply. There is some evidence which suggests that the constitutive and the induced NO;; carriers may be distinct; they may turn over at different rates and the Km of the former is smaller. When cells are deprived of nitrate there is a loss of the induced carrier (= decay) but there may be an increase in the constitutive carrier. During N-starvation both Km and V max of net uptake and influx may vary.Evidence suggests that NO; influx is coupled to the proton motive force across the plasma membrane. NO; influx is usually accompanied by alkalinization of the external solution, but the effects of influx on the membrane potential are not always those to be expected for a 2H+: NO; symport. The insensitivity of NO;; influx to inhibition of proton pump activity by DES suggests that it may be premature to decide on the type of mechanism which carries NO;.The efflux of nitrate from the cytoplasmic pool is rapid and in many circumstances efflux may be a substantial proportion of the net uptake. Evidence is considered which suggests that net uptake is strongly controlled by the size of the efflux, influx being relatively constant. This view, however, does not take into account well-documented effects of the inhibition of uptake via the pool of amino compounds in the cytoplasm; the depression of uptake caused by NH; is probably indirect and mediated through the amino acid pool. Some evidence shows that NH; can promote rapid NO; efflux while having little or no short-term effect on influx.The net uptake of nitrate across the plasmalemma appears to be regulated jointly by the size of the cytoplasmic pool of NO;; -which influences efflux, and of amino acids -which influences influx. Fluxes across the tonoplast appear to be regulated, in unknown ways, by the vacuolar concentration of NO; + Cl-and perhaps other anions.The prospects for understanding regulation will be improved when it is possible to get better measurements of the metabolic/transport pool of NO;; in the cytoplasm. Some preliminary approaches to compartmentation using NMR spectroscopy are briefly described.

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“…IIA, this Vol.). More recently, nitrobenzaldehyde and derivatives have been found to specifically compete with nitrate at its uptake site (TISCHNER and LoRENZEN 1981).…”

Section: Effect Of Metabolic Inhibitors and Uncouplersmentioning

confidence: 99%

Uptake and Reduction of Nitrate: Algae and Fungi

Ullrich¹

1983

Inorganic Plant Nutrition

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Nitrate Uptake and Reduction in Chlorella — Characterisation of Nitrate Uptake in Nitrate-Grown and Nitrogen-Starved Chlorella sorokiniana

Cited by 14 publications

References 14 publications

Effect of nitrate pulses on the nitrate-uptake rate, synthesis of mRNA coding for nitrate reductase, and nitrate-reductase activity in the roots of barley seedlings

Effect of nitrate pulses on the nitrate-uptake rate, synthesis of mRNA coding for nitrate reductase, and nitrate-reductase activity in the roots of barley seedlings

Regulation of the absorption and release of nitrate by plant cells: A review of current ideas and methodology

Uptake and Reduction of Nitrate: Algae and Fungi

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