scholarly journals Nitrate reductase and acid phosphatase activities as affected by inorganic phosphate in corn roots

2014 ◽  
Vol 52 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Marie Kummerova ◽  
Józef Buczek
Keyword(s):  
Acid Phosphatase ◽  
Nitrate Reductase ◽  
Nutrient Solution ◽  
Inorganic Phosphate ◽  
Acid Phosphatases ◽  
Weak Effect ◽  
Corn Roots ◽  
Nr Activity

The deficieny of inorganic phosphate in nutrient solution reduces by about 50 per cent NO<sub>3</sub>- absorption in corn seedlings, it decreases both <em>in vitro</em> and in vivo nitrate reductase (NR) activity, as well the potential and actual NR level and has a very weak effect on NR induction. Acid phosphatases activities increase in corn roots when the plants are grown in nutrient solution without phosphorus. We suggest that inorganic phosphate is required mainly for maintenance of NR activity rather, than for induction <em>in vivo</em> of nitrate reductase. It is not excluded that deficiency of inorganic phosphate in root tissue may be partly supplemented as the result of enhanced acid phosphatase activity.

scholarly journals Inhibition of nitrate reductase and ATPase activities in Zea mays roots by tungsten and N, N'-dicyclohexylcarbodiimide

2014 ◽  
Vol 50 (3) ◽  
pp. 455-464
Author(s):  
Józef Buczek ◽  
Marek Burzyński ◽  
Anna Suder-Moraw
Keyword(s):  
Zea Mays ◽  
Nitrate Reductase ◽  
Nutrient Solution ◽  
Additional Mechanism ◽  
Corn Roots ◽  
Membrane Bound ◽  
Nr Activity

The activity of soluble and membrane-bound ATPase obtained from corn roots was in vivo markedly inhibited by N,N' -dicyclohexylcanbodiimide (DCCD) and W0<sub>4</sub><sup>2-</sup> ions. DCCD (2.5 X 10<sup>-5</sup> M) added to the nutrient solution strongly decreased in vivo nitrate reductase (NR) activity after 12-h growth of plants while it had no effect in experiments <em>in vitro</em> on NR activity. Tungsten in a concentration of 10<sup>-4</sup> M completely blocked NR activity after 24 h. In the above used concentrations neither DCCD nor W0<sub>4</sub><sup>2-</sup> inhibited completely N0<sub>3</sub><sup>-</sup> absorption by corn roots. The results suggest that there must exist in corn roots another or an additional mechanism of N0<sub>3</sub><sup>-</sup> assimilation apart from of that proposed by Butz and Jackson (1977).

In vivo Nitrate Reductase Activity in Leaves of Pearl Millet, Pennisetum americanum (L.) Leeke

1987 ◽  
Vol 14 (2) ◽  
pp. 125 ◽  
Author(s):  
SV Chanda ◽  
AK Joshi ◽  
PN Krishnan ◽  
YD Singh
Keyword(s):  
Nitrate Reductase ◽  
Reductase Activity ◽  
Potassium Phosphate ◽  
Limiting Factor ◽  
Growth Stages ◽  
In Vivo Assay ◽  
Rate Limiting ◽  
Nr Activity

In the in vivo assay of nitrate reductase (NR) in P. americanum leaves, addition of 1% (v/v) Triton X-100, potassium phosphate buffer (80 mM, pH 7.4) and 1.13 mM NADH to the assay medium resulted in maximum activity. With increasing concentration of NADH, saturation-type kinetics were observed. Based on this data metabolic pool concentration for NADH and apparent Km for nitrate reductase were determined. In field studies with cultivars BJ-104, J-104 and 5141-A of P. americanum, the relative limitation of NO3-, NADH and nitrate reductase in NO3- assimilation was determined. NR activity was measured by four modifications of the in vivo assay technique (with NO3-, with NADH, without NO3- and NADH and with both NO3- and NADH additions to the reaction mixture) and with one in vitro technique. For all the cultivars, NADH was the major rate-limiting factor for in vivo assay during early growth stages, while at later stages, NO3- was limiting. At no stage was NR rate-limiting. It is concluded that NR activity alone may not serve as biochemical marker for improved efficiency of utilisation of nitrogen in P. americanum.

scholarly journals The role of light in the inducation of nitrate reductase and nitrite reductase in cucumber seedlings

2015 ◽  
Vol 45 (1–2) ◽  
pp. 77-92 ◽  
Author(s):  
J. Buczek
Keyword(s):  
Nitrate Reductase ◽  
Nitrite Reductase ◽  
De Novo ◽  
Activity Level ◽  
Induction Medium ◽  
Cucumber Seedlings ◽  
Nr Activity

The activity of nitrate reductase (NR) and nitrite reductase (NiR) was investigated in vivo and in vitro in the roots and NR activity in 3-day-old cotyledons of cucumber seedlings. NR activity in the roots appears almost immediately after addition of nitrate ions to the induction medium, whereas, in the cotyledones NR induction is delayed. In general light enhances NR activity in the cotyledons and depresses it in the roots in experiments of short duration. Etiolation of the cotyledons reduces NR activity in the roots and leads to disappearance of the activity of this enzyme in the cotyledons, whereas the NR activity of roots kept in darkness, after transfer of the etiolated plants to light, increases threefold. In roots growing in darkness a delay in NiR induction is observed, while in those growing in ligth it occurs at the same time as NR induction. Chlormaphenicol (CAP), cycloheximide (CHI) and actinomycin D (ACM) applied at the beginning of the period of seedling induction with initrates inhibit NR activity in the cotyledons, whereas in the roots only CHI and ACM exert such an effect. To sum up, NR is synthesized in cucumber roots and cotyledons de novo on the cytoplasmic polyribosomes, and light per se is not indispensable for this synthesis, but it has an indirect influence on the activity level of NR and NiR both in the roots and the cotyledons.

scholarly journals Activation of nitrate reductase of cashew leaf by exogenous nitrite

2002 ◽  
Vol 14 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Ricardo Almeida Viégas ◽  
Joaquim Albenísio Gomes Silveira
Keyword(s):  
Nitrate Reductase ◽  
Reaction Medium ◽  
No Oxidation ◽  
Primary Metabolism ◽  
Leaf Extracts ◽  
Enzymatic Extract ◽  
Regulation Mechanisms ◽  
Nr Activity

Nitrate reductase (NR) plays a central role in plant primary metabolism and exhibits complex regulation mechanisms for its catalytic activity. There is controversy in the literature concerning the possible direct effect of NO2- on the stimulation and/or activation of NR activity. The influence of NO2- was studied on the NR activity in the leaves of 30-day-old cashew (Anacardium occidentale L.) seedlings. Addition of NO2- to the reaction mixture containing leaf enzymatic extract resulted in a remarkable increase in NR activity. A trace amount (5 mumol.L-1) of NO2- was required to achieve full NR activity. The in vitro NR-activity showed a steady time-dependent increase when incubated in the presence of only NO3- + NO2-. In contrast, in vitro NR activity was practically absent in a NO2- -free reaction medium, even in the presence of a saturating NO3- concentration. No oxidation of NO2- to NO3- was detected during the experiment. Although NO2- clearly activated the in vitro NR activity, it had no effect on the in vivo leaf-NR activity determined under absence of oxygen. NADH at concentrations greater than 0.5 mmol.L-1 decreased the rates of in vitro NR activity. These results indicated, at least partially, a strong cashew leaf NO2- dependency of NR activation and/or activity. Finally, based on these results, it is suggested that this singular NR activity model induced by exogenous NO2- in cashew leaf extracts is caused by changes in the NR activation state by NO2- itself.

scholarly journals Genetic and biochemical analysis of intragenic complementation events among nitrate reductase apoenzyme-deficient mutants of Nicotiana plumbaginifolia.

Genetics ◽  
1991 ◽  
Vol 127 (1) ◽  
pp. 199-204 ◽  
Author(s):  
F Pelsy ◽  
M Gonneau
Keyword(s):  
Nitrate Reductase ◽  
Molecular Data ◽  
Nicotiana Plumbaginifolia ◽  
Wild Type Plant ◽  
Catalytic Domains ◽  
Intragenic Complementation ◽  
In The Wild ◽  
Nr Activity

Abstract Intragenic complementation has been observed between apoenzyme nitrate reductase-deficient mutants (nia) of Nicotiana plumbaginifolia. In vivo as in vitro, the NADH-nitrate reductase (NR) activity in plants heterozygous for two different nia alleles was lower than in the wild type plant, but the plants were able to grow on nitrate as a sole nitrogen source. NR activity, absent in extracts of homozygous nia mutants was restored by mixing extracts from two complementing nia mutants. These observations suggest that NR intragenic complementation results from either the formation of heteromeric NR or from the interaction between two modified enzymes. Complementation was only observed between mutants retaining different partial catalytic activities of the enzyme. Results are in agreement with molecular data suggesting the presence of three catalytic domains in the subunit of the enzyme.

scholarly journals Assessment of Acid Phosphatase Production by In vitro Cultures of Atropa acuminata

2016 ◽  
Vol 26 (1) ◽  
pp. 15-23
Author(s):  
Saima Khan ◽  
Meenu Katoch ◽  
Sharada Mallubhotla ◽  
Suphla Gupta ◽  
Manju Sambyal ◽  
...  
Keyword(s):  
Acid Phosphatase ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Growth Period ◽  
Callus Cultures ◽  
Shoot Cultures ◽  
Crude Enzyme Extract ◽  
Atropa Acuminata

The potential of various culture lines of Atropa acuminata were investigated for resourcing acid phosphatase (ACP) (3.1.3.2). Crude enzyme extract comprised of a mixture of four isoforms, distinguishable by polyacrylamide gel electrophoresis (PAGE) with molecular weight ranging from 39 to 215 kDa. In vitro regenerated proliferative shoots, callus and roots showed higher specific activity (2.49, 3.41, 2.91 U/mg protein, respectively) as compared to in vivo grown plants (0.71 U/mg protein). ACP activity in root cultures increased progressively up to 4.6 U/mg during the entire growth period (2 ? 24 weeks), whereas in case of shoot cultures, the specific activity escalated to 2.49 U/mg at 8 weeks, which then declined subsequently (1.95 U/mg). Similarly, callus cultures initially showed a higher phosphohydrolytic activity (3.41 U/mg protein) until 8 weeks by which period, it decreased with the passage of growth period. The present studies reveal an alternate system for resourcing of ACP from Atropa acuminata.Plant Tissue Cult. & Biotech. 26(1): 15-23, 2016 (June)

In vitro translation of human prostatic acid phosphatase mRNA and processing of the translation products by microsomal membranes and endoglycosidase H

1987 ◽  
Vol 65 (10) ◽  
pp. 921-924 ◽  
Author(s):  
Gilles Paradis ◽  
Jean Y. Dubé ◽  
Pierre Chapdelaine ◽  
Roland R. Tremblay
Keyword(s):  
Acid Phosphatase ◽  
Molecular Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Prostatic Acid Phosphatase ◽  
In Vitro Translation ◽  
Acid Phosphatases ◽  
Major Band ◽  
Microsomal Membranes ◽  
Endoglycosidase H

Poly(A)+ RNA was isolated from human prostatic tissue and translated in vitro in a rabbit reticulocyte lysate translation assay. Acid phosphatase labeled with [35S]methionine was immunoprecipitated with an antibody against seminal plasma acid phosphatase. Two-dimensional polyacrylamide gel electrophoresis of the immunoprecipitate, followed by fluorography, revealed the presence of two spots (one major and one minor), both having a molecular mass of 43 kilodaltons (kDa) and an isoelectric point higher than mature acid phosphatase. Addition of canine pancreatic membranes to the translation assay resulted in the formation of four immunoprecipitable spots with molecular masses ranging from 43 to 49 kDa on one-dimensional gels. These spots probably represent acid phosphatases containing one to four core sugar groups, since after the addition of endoglycosidase H the molecular mass heterogeneity was abolished and we observed only one major band with a molecular mass (41 kDa) slightly lower than the ones of the primary translation product. These results suggest that human prostatic acid phosphatases are synthesized as two 43-kDa preproteins, which are further processed to 41-kDa proteins by removal of their signal peptide. Heterogeneity of the native protein arises mostly from glycosylation at four sites and not from differences in the amino acid sequence of the various forms.

Sign in / Sign up

Export Citation Format

Share Document