The role of malate in nitrate reduction in spinach leaves

1980 ◽  
Vol 58 (5) ◽  
pp. 517-521 ◽  
Author(s):  
K. C. Woo ◽  
D. T. Canvin
Keyword(s):  
Nitrate Reduction ◽  
Nitrite Accumulation ◽  
Antimycin A ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Leaf Discs ◽  
Spinach Leaf ◽  
Spinach Leaves

In spinach leaf discs the accumulation of nitrite from nitrate reduction under anaerobic conditions in the light in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) was inhibited by air. The inhibition of nitrate reduction by air was reversed by antimycin A but not by rotenone or amytal. The nitrate-reducing system of DCMU-inhibited leaf discs in the light appeared similar to noninhibited leaf discs in the dark. In aerobic conditions, the addition of malate stimulated nitrite accumulation. This stimulation was unaffected by malonate. Under anaerobic conditions, malate reversed the inhibition of nitrate reduction caused by either iodoacetate or arsenite to rates similar to those observed in the dark and in the light with DCMU. Malate can apparently provide a direct source of cytosolic NADH for nitrate reduction.

The regulation of nitrate reduction in spinach leaves

1979 ◽  
Vol 57 (10) ◽  
pp. 1155-1160 ◽  
Author(s):  
David T. Canvin ◽  
K. C. Woo
Keyword(s):  
Electron Transport ◽  
Nitrate Reduction ◽  
Electron Transport Chain ◽  
Antimycin A ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Transport Chain ◽  
Respiratory Electron Transport ◽  
Spinach Leaves

Nitrate reduction did not occur in leaves in the dark in aerobic conditions but did occur in anaerobic conditions. Nitrate reduction in leaves in the dark in aerobic conditions was observed, however, when the respiratory electron transport chain was inhibited with antimycin A but not when it was inhibited with amytal or rotenone. It would appear that NADH generated outside the mitochondria was used for nitrate reduction in the dark under anaerobic conditions. The relevance of this observation to nitrate reduction in the light is discussed.

scholarly journals The Periplasmic Nitrate Reductase inPseudomonas sp. Strain G-179 Catalyzes the First Step of Denitrification

1999 ◽  
Vol 181 (9) ◽  
pp. 2802-2806 ◽  
Author(s):  
Laura Bedzyk ◽  
Tao Wang ◽  
Rick W. Ye
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Primary Role ◽  
Anaerobic Conditions ◽  
It Use ◽  
Alternative Substrate ◽  
Periplasmic Nitrate Reductase ◽  
Reduction Activity ◽  
Membrane Bound

ABSTRACT Both membrane-bound and periplasmic nitrate reductases have been found in denitrifying bacteria. Yet the role of periplasmic nitrate reductase in denitrification has not been clearly defined. To analyze the function of the periplasmic nitrate reductase inPseudomonas sp. strain G-179, the nap gene cluster was identified and found to be linked to genes involved in reduction of nitrite and nitric oxide and anaerobic heme biosynthesis. Mutation in the nap region rendered the cells incapable of growing under anaerobic conditions with nitrate as the alternative electron acceptor. No nitrate reduction activity was detected in the Nap− mutant, but that activity could be restored by complementation with the nap region. Unlike the membrane-bound nitrate reductase, the nitrate reduction activity in strain G-179 was not inhibited by a low concentration of azide. Nor could it use NADH as the electron donor to reduce nitrate or use chlorate as the alternative substrate. These results suggest that the periplasmic nitrate reductase in this strain plays a primary role in dissimilatory nitrate reduction.

METABOLISM OF MAMMALIAN ERYTHROCYTES: V. ROLE OF CATALASE IN THE OXIDATION OF RIBOSE-5-PHOSPHATE BY THE ERYTHROCYTE

1954 ◽  
Vol 32 (6) ◽  
pp. 644-654 ◽  
Author(s):  
Marc Francoeur ◽  
Orville F. Denstedt
Keyword(s):  
Hydrogen Peroxide ◽  
Methylene Blue ◽  
Glucose Oxidase ◽  
Anaerobic Conditions ◽  
Beef Liver ◽  
Aerobic Conditions

Ribose-5-phosphate has been found to be rapidly oxidized by the stroma-free hemolyzate of human, rat, and rabbit erythrocytes in the presence of ferricyanide under anaerobic conditions, or in the presence of methylene blue under aerobic conditions. Compounds resembling R-5-P, such as ribose, arabinose, xylose, glucose, glucose-6-phosphate, fructose-6-phosphate, and hexose diphosphate are not oxidized under these conditions. The oxidation does not involve DPN or TPN and it is completely inhibited by cyanide. The Ks is about 2 × 10−2 M. Under anaerobic conditions, in the presence of ferricyanide, the enzyme responsible for the oxidation is catalase. Purified catalase from beef liver or from rabbit erythrocytes yields the same results as the SFH from human, rat, or rabbit erythrocytes with respect to specificity, cyanide sensitivity, and the Ks value. Under aerobic conditions, catalase is responsible also for the oxidation of R-5-P, but the mechanism involves the peroxidase action of catalase. Catalase catalyzes the oxidation of R-5-P by hydrogen peroxide in the presence of a system which slowly generates hydrogen peroxide, such as the glucose–glucose oxidase or the hemoglobin – methylene blue systems.

Kinetics and Regulation of the NAD(P)H-Dependent Glyoxylate-Specific Reductase from Spinach Leaves

1995 ◽  
Vol 50 (1-2) ◽  
pp. 21-28 ◽  
Author(s):  
Leszek A. Kleczkowski
Keyword(s):  
Potent Inhibitor ◽  
Kinetic Mechanism ◽  
Plant Tissues ◽  
Ping Pong ◽  
Spinach Leaf ◽  
Sequential Addition ◽  
Glyoxylate Reductase ◽  
Spinach Leaves

Abstract Kinetic mechanism of purified spinach leaf NAD(P)H glyoxylate reductase (GR-1) was studied using either NADPH and NADH as alternative substrates with glyoxylate. The mech­anism was elucidated from substrate kinetic patterns using NADH as a cofactor rather than NADPH. With NADPH varied versus glyoxylate, and with NADPH and glyoxylate varied at a constant ratio, the patterns obtained on double reciprocal plots appeared to be consistent with a ping-pong mechanism; however, kinetic patterns with NADH conclusively ruled out the ping-pong reaction in favour of the sequential addition of the reactants. Product inhi­bition studies with glycolate and NADP have suggested either that NADPH binds to the enzyme before glyoxylate or that the addition of substrates is a random one. Studies with active group modifiers suggested an involvement of histidine, serine and cysteine residues in GR-1 activity. Salts had little or no effect on the activity of the enzyme, with the exception of cyanide, which had an apparent Ki of ca. 2 mᴍ. Studies with several metabolites used as possible effectors of GR-1 activity have suggested that the enzyme is modulated only by substrate availability in vivo. The apparent insensitivity of GR-1 to metabolic effectors is consistent with the proposed role of the enzyme in detoxifying glyoxylate which may act as a potent inhibitor of photosynthetic processes in plant tissues.

scholarly journals Low C/N Ratios Promote Dissimilatory Nitrite Reduction to Ammonium in Pseudomonas putida Y-9 under Aerobic Conditions

2021 ◽  
Vol 9 (7) ◽  
pp. 1524
Author(s):  
Xuejiao Huang ◽  
Wenzhou Tie ◽  
Deti Xie ◽  
Zhenlun Li
Keyword(s):  
Pseudomonas Putida ◽  
Nitrate Reduction ◽  
Sodium Acetate ◽  
Sodium Citrate ◽  
Experimental System ◽  
N Cycling ◽  
Nitrite Reduction ◽  
Limited Information ◽  
Anaerobic Conditions ◽  
Aerobic Conditions

The biogeochemical consequences of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) have a significant influence on nitrogen (N) cycling in the ecosystem. Many researchers have explored these two pathways in soil and sediment ecosystems under anaerobic conditions. However, limited information is available regarding the influence of external environmental conditions on these two pathways in a well-defined experimental system under aerobic conditions. In this study, the impacts of the external environmental factors (carbon source, C/N ratio, pH, and dissolved oxygen) on nitrite reduction through the denitrification and DNRA routes in Pseudomonas putida Y-9 were studied. Results found that sodium citrate and sodium acetate favored denitrification and DNRA, respectively. Furthermore, neutral pH and aerobic conditions both facilitated DNRA and denitrification. Especially, low C/N ratios motivated the DNRA while high C/N ratios stimulated the denitrification, which was opposite to the observed phenomena under anaerobic conditions.

METABOLISM OF MAMMALIAN ERYTHROCYTES: V. ROLE OF CATALASE IN THE OXIDATION OF RIBOSE-5-PHOSPHATE BY THE ERYTHROCYTE

1954 ◽  
Vol 32 (1) ◽  
pp. 644-654 ◽  
Author(s):  
Marc Francoeur ◽  
Orville F. Denstedt
Keyword(s):  
Hydrogen Peroxide ◽  
Methylene Blue ◽  
Glucose Oxidase ◽  
Anaerobic Conditions ◽  
Beef Liver ◽  
Aerobic Conditions

Ribose-5-phosphate has been found to be rapidly oxidized by the stroma-free hemolyzate of human, rat, and rabbit erythrocytes in the presence of ferricyanide under anaerobic conditions, or in the presence of methylene blue under aerobic conditions. Compounds resembling R-5-P, such as ribose, arabinose, xylose, glucose, glucose-6-phosphate, fructose-6-phosphate, and hexose diphosphate are not oxidized under these conditions. The oxidation does not involve DPN or TPN and it is completely inhibited by cyanide. The Ks is about 2 × 10−2 M. Under anaerobic conditions, in the presence of ferricyanide, the enzyme responsible for the oxidation is catalase. Purified catalase from beef liver or from rabbit erythrocytes yields the same results as the SFH from human, rat, or rabbit erythrocytes with respect to specificity, cyanide sensitivity, and the Ks value. Under aerobic conditions, catalase is responsible also for the oxidation of R-5-P, but the mechanism involves the peroxidase action of catalase. Catalase catalyzes the oxidation of R-5-P by hydrogen peroxide in the presence of a system which slowly generates hydrogen peroxide, such as the glucose–glucose oxidase or the hemoglobin – methylene blue systems.

Metabolism of hydroxylamine by spinach leaf discs and its relationship to nitrate reduction

Planta ◽  
1981 ◽  
Vol 151 (2) ◽  
pp. 151-156 ◽  
Author(s):  
D. P. Hucklesby ◽  
M. J. Dowling ◽  
E. J. Hewitt
Keyword(s):  
Nitrate Reduction ◽  
Leaf Discs ◽  
Spinach Leaf

The Reaction of Thiol Compounds with the Vitamin-K Dependent Clotting Factors

1969 ◽  
Vol 21 (03) ◽  
pp. 573-579 ◽  
Author(s):  
P Fantl
Keyword(s):  
Prothrombin Time ◽  
Vitamin K ◽  
Anaerobic Conditions ◽  
Clotting Factors ◽  
Thiol Compounds ◽  
Aerobic Conditions ◽  
One Stage ◽  
Factor Ii ◽  
Ph Dependent ◽  
The One

SummaryTreatment of human and dog oxalated plasma with 0.2 to 1.0 × 10−1 M 2.3-dithiopropanol (BAL) or dithiothreitol (DTT) at 2–4° C for 30 min results in the reduction of the vitamin-K dependent clotting factors II, VII, IX and X to the respective-SH derivatives. The reaction is pH dependent. Under aerobic conditions the delayed one stage prothrombin time can be partly reversed. Under anaerobic conditions a gradual prolongation of the one stage prothrombin time occurs without reversal.In very diluted plasma treated with the dithiols, prothrombin can be converted into thrombin if serum as source of active factors VII and X is added. In contrast SH factors VII, IX and X are inactive in the specific tests. Reoxidation to active factors II, VII, IX and X takes place during adsorption and elution of the SH derivatives. The experiments have indicated that not only factor II but also factors VII, IX and X have active-S-S-centres.

Performance of aerobic granular sludge at variable circulation rate in anaerobic–aerobic conditions

2014 ◽  
Vol 69 (11) ◽  
pp. 2252-2257 ◽  
Author(s):  
Hasnida Harun ◽  
Aznah Nor Anuar ◽  
Zaini Ujang ◽  
Noor Hasyimah Rosman ◽  
Inawati Othman
Keyword(s):  
Municipal Wastewater ◽  
Granular Sludge ◽  
Ammonia Removal ◽  
Soy Sauce ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Circulation Rate ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Mixed Liquor

Aerobic granular sludge (AGS) has been applied to treat a broad range of industrial and municipal wastewater. AGS can be developed in a sequencing batch reactor (SBR) with alternating anaerobic–aerobic conditions. To provide anaerobic conditions, the mixed liquor is allowed to circulate in the reactor without air supply. The circulation flow rate of mixed liquor in anaerobic condition is the most important parameter of operation in the anaerobic-AGS processes. Therefore, this study investigates the effect of circulation rate on the performance of the SBR with AGS. Two identical reactors namely R1 and R2 were operated using fermented soy sauce wastewater at circulation rate of 14.4 and 36.0 l/h, respectively. During the anaerobic conditions, the wastewater was pumped out from the upper part of the reactor and circulated back into the bottom of the reactor for 230 min. A compact and dense AGS was observed in both reactors with a similar diameter of 2.0 mm in average, although different circulation rates were adopted. The best reactor performance was achieved in R2 with chemical oxygen demand removal rate of 89%, 90% total phosphorus removal, 79% ammonia removal, 10.1 g/l of mixed liquor suspended solids and a sludge volume index of 25 ml/g.

scholarly journals The Role of Electron Transport in Determining the Temperature Dependence of the Photosynthetic Rate in Spinach Leaves Grown at Contrasting Temperatures

2008 ◽  
Vol 49 (4) ◽  
pp. 583-591 ◽  
Author(s):  
Wataru Yamori ◽  
Ko Noguchi ◽  
Yasuhiro Kashino ◽  
Ichiro Terashima
Keyword(s):  
Electron Transport ◽  
Temperature Dependence ◽  
Photosynthetic Rate ◽  
Spinach Leaves
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