scholarly journals Molybdoenzyme Participation In Plant Biochemical Processes

2021 ◽  
Author(s):  
D.S. Tokasheva ◽  
Zh.A. Nurbekova ◽  
A.Zh. Akbassova ◽  
R.T. Omarov
Keyword(s):  
Nitrate Reductase ◽  
Sulfur Metabolism ◽  
Plant Stress ◽  
Nitrate Assimilation ◽  
Aldehyde Oxidase ◽  
Xanthine Dehydrogenase ◽  
Biochemical Processes ◽  
Oxidation Reduction ◽  
Hormone Biosynthesis ◽  
Molybdate Anion

Molybdenum is a key microelement in plant vital functioning. The microelement can be absorbed by the plants only in the form of molybdate-anion.  The Molybdenum deficiency affects negatively to the most important agricultural growing.  As molybdenum takes part in such vital mechanisms as nitrogen and sulfur metabolism, plant hormone biosynthesis, and purine banding catabolism. Molybdenum is included in enzyme content which is called molybdoenzyms. Having bonded with molybdopterin it creates molybdenum co-factor (Moco) and gets oxidation-reduction properties. Moco is included in active site of molybdoenzymes. They take part in sulfur and nitrogen metabolism, and detrimental compound detoxication. Molybdenum deficiency is characterized by the slow plant growth, low amount of chlorophyll ascorbic acid capacity.It was noticed that plants suffering from the molybdenum deficiency can be saved, sodium molibdate can be used, it can be put directly in the soil or plant leaves can sprayed with the solution. There are five plant molibdoenzymes which are currently known: sulfite oxidase (SO), xanthine dehydrogenase (XD), nitrate reductase (NR), aldehyde oxidase (AO) and mitochondrial amidoxim-regenerative component. Nitrate reductase catalyzes the first stage of nitrate assimilation, eucariotic organisms contain three isoforms of the molybdoezimes: A NADH, A NAD(P)H и NADPH.  Xanthine dehydrogenase regulates purine metabolism. XD increases plant antioxidant ability and slows down leaves aging. Molybdoenzymess are involved in the process of the stress adaptation, defining of the mechanisms and their reaction to environmental stress conditions is important for plant stress resistance.

scholarly journals THE ISOLATION AND CHARACTERIZATION OF MUTANTS DEFECTIVE IN NITRATE ASSIMILATION IN NEUROSPORA CRASSA

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 649-660
Author(s):  
A Brian Tomsett ◽  
Reginald H Garrett
Keyword(s):  
Nitrate Reductase ◽  
Neurospora Crassa ◽  
Nitrate Assimilation ◽  
Xanthine Dehydrogenase ◽  
Growth Patterns ◽  
Isolation And Characterization ◽  
Complex Locus ◽  
Complementation Groups ◽  
Nitrate And Nitrite

ABSTRACT The isolation and characterization of mutants altered for nitrate assimilation in Neurospora crassa is described, The mutants isolated can be subdivided into five classes on the basis of growth tests that correspond to the growth patterns of existing mutants at six distinct loci. Mutants with growth characteristics like those of nit-2, nit-3 and nit-6 are assigned to those loci on the basis of noncomplementation and lack of recombination. Mutants that, from their growth patterns, appear to lack the molybdenum-containing cofactor for both nitrate reductase and xanthine dehydrogenase subdivide into three loci (nit-7, nit4 and nit-9), all of which are genetically distinct from nit-1. nit-9 is a complex locus consisting of three complementation groups and thus appears similar to the cnxABC locus of Asperillus nidulans. Extensive complementational and recombinational analyses reveal that nit-4 and nit-5 are alleles of the same locus, and two new alleles of that locus have been isolated. The results indicate that, as in A. nidulans, nitrate assimilation in N. crassa requires at least four loci (nit-1,7,8 and 9) to produce the molybdenum co-factor for nitrate reductase (and xanthine dehydrogenase), one locus (nit-3) to code for the nitrate reductase apoprotein, one locus (nit-6) to code for the nitrite reductase approtein and only one locus (nit-4/5) for the regulation of induction of the pathway by nitrate and nitrite.

scholarly journals Identification of a new mutation in the human xanthine dehydrogenase responsible for xanthinuria type I

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Cristina Collazo Abal ◽  
Susana Romero Santos ◽  
Carmen González Mao ◽  
Emilio C. Pazos Lago ◽  
Francisco Barros Angueira ◽  
...  
Keyword(s):  
Aldehyde Oxidase ◽  
Renal Calculi ◽  
Xanthine Dehydrogenase ◽  
Type I ◽  
Dietary Recommendations ◽  
New Mutation ◽  
Case Presentation ◽  
Hereditary Xanthinuria ◽  
Urine Levels ◽  
Made In

Abstract Objectives Hereditary xanthinuria is a rare, autosomal and recessive disorder characterized by severe hypouricemia and increased xanthine excretion, caused by a deficiency of xanthine dehydrogenase/oxidase (XDH/XO, EC: 1.17.1.4/1.17.3.2) in type I, or by a deficiency of XDH/XO and aldehyde oxidase (AOX, EC: 1.2.3.1) in type II. Case presentation We describe a novel point mutation in the XDH gene in homozygosis found in a patient with very low serum and urine levels of uric acid, together with xanthinuria. He was asymptomatic but renal calculi were discovered during imaging. Additional cases were found in his family and dietary recommendations were made in order to prevent further complications. Conclusions Hereditary xanthinuria is an underdiagnosed pathology, often found in a routine analysis that shows hypouricemia. It is important for Laboratory Medicine to acknowledge how to guide clinicians in the diagnosis.

Significance of nitrate reductase in nitrate assimilation in free-livingRhizobium cultures

1982 ◽  
Vol 38 (10) ◽  
pp. 1208-1210 ◽  
Author(s):  
M. H. Siddiqui ◽  
Anjali Mathur ◽  
S. N. Mathur
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Assimilation

scholarly journals Reticulate evolution in eukaryotes: origin and evolution of the nitrate assimilation pathway

2018 ◽  
Author(s):  
Eduard Ocaña-Pallarès ◽  
Sebastián R. Najle ◽  
Claudio Scazzocchio ◽  
Iñaki Ruiz-Trillo
Keyword(s):  
Nitrate Reductase ◽  
Gene Fusion ◽  
Evolutionary History ◽  
Transcriptional Control ◽  
Genetic Material ◽  
Nitrate Assimilation ◽  
Nitrogen Sources ◽  
Reticulate Evolution ◽  
Origin And Evolution ◽  
Ideal Object

AbstractGenes and genomes can evolve through interchanging genetic material, this leading to reticular evolutionary patterns. However, the importance of reticulate evolution in eukaryotes, and in particular of horizontal gene transfer (HGT), remains controversial. Given that metabolic pathways with taxonomically-patchy distributions can be indicative of HGT events, the eukaryotic nitrate assimilation pathway is an ideal object of investigation, as previous results revealed a patchy distribution and suggested one crucial HGT event. We studied the evolution of this pathway through both multi-scale bioinformatic and experimental approaches. Our taxon-rich genomic screening shows this pathway to be present in more lineages than previously proposed and that nitrate assimilation is restricted to autotrophs and to distinct osmotrophic groups. Our phylogenies show a pervasive role of HGT, with three bacterial transfers contributing to the pathway origin, and at least seven well-supported transfers between eukaryotes. Our results, based on a larger dataset, differ from the previously proposed transfer of a nitrate assimilation cluster from Oomycota (Stramenopiles) to Dikarya (Fungi, Opisthokonta). We propose a complex HGT path involving at least two cluster transfers between Stramenopiles and Opisthokonta. We also found that gene fusion played an essential role in this evolutionary history, underlying the origin of the canonical eukaryotic nitrate reductase, and of a novel nitrate reductase in Ichthyosporea (Opisthokonta). We show that the ichthyosporean pathway, including this novel nitrate reductase, is physiologically active and transcriptionally co-regulated, responding to different nitrogen sources; similarly to distant eukaryotes with independent HGT-acquisitions of the pathway. This indicates that this pattern of transcriptional control evolved convergently in eukaryotes, favoring the proper integration of the pathway in the metabolic landscape. Our results highlight the importance of reticulate evolution in eukaryotes, by showing the crucial contribution of HGT and gene fusion in the evolutionary history of the nitrate assimilation pathway.

scholarly journals Inactivation of gltB Abolishes Expression of the Assimilatory Nitrate Reductase Gene (nasB) in Pseudomonas putida KT2442

2000 ◽  
Vol 182 (12) ◽  
pp. 3368-3376 ◽  
Author(s):  
Leo Eberl ◽  
Aldo Ammendola ◽  
Michael H. Rothballer ◽  
Michael Givskov ◽  
Claus Sternberg ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Pseudomonas Putida ◽  
Nitrogen Starvation ◽  
Nitrate Assimilation ◽  
Glutamate Synthase ◽  
Nitrogen Sources ◽  
Nucleotide Sequence Analysis ◽  
Nitrate Reductase Gene ◽  
Physiological Characterization ◽  
Reductase Gene

ABSTRACT By using mini-Tn5 transposon mutagenesis, random transcriptional fusions of promoterless bacterial luciferase,luxAB, to genes of Pseudomonas putida KT2442 were generated. Insertion mutants that responded to ammonium deficiency by induction of bioluminescence were selected. The mutant that responded most strongly was genetically analyzed and is demonstrated to bear the transposon within the assimilatory nitrate reductase gene (nasB) of P. putida KT2442. Genetic evidence as well as sequence analyses of the DNA regions flanking nasBsuggest that the genes required for nitrate assimilation are not clustered. We isolated three second-site mutants in which induction ofnasB expression was completely abolished under nitrogen-limiting conditions. Nucleotide sequence analysis of the chromosomal junctions revealed that in all three mutants the secondary transposon had inserted at different sites in the gltB gene of P. putida KT2442 encoding the major subunit of the glutamate synthase. A detailed physiological characterization of thegltB mutants revealed that they are unable to utilize a number of potential nitrogen sources, are defective in the ability to express nitrogen starvation proteins, display an aberrant cell morphology under nitrogen-limiting conditions, and are impaired in the capacity to survive prolonged nitrogen starvation periods.

Nitrate Reductase from a Mutant Strain of Chlamydomonas reinhardii Incapable of Nitrate Assimilation

1983 ◽  
Vol 38 (5-6) ◽  
pp. 439-445 ◽  
Author(s):  
Emilio Fernández ◽  
Jacobo Cárdenas
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Wild Strain ◽  
Nitrate Assimilation ◽  
Pyridine Nucleotide ◽  
Spectral Studies ◽  
Binding Region ◽  
Chlamydomonas Reinhardii ◽  
Blue Sepharose

Nitrate reductase from mutant 305 of Chlamydomonas reinhardii has been purified about 90-fold and biochemically characterized. The enzyme can use reduced flavins and viologens as electron donors to reduce nitrate but, unlike the nitrate reductase complex from its parental wild strain, lacks NAD(P)H-nitrate reductase and NAD(P)H-cytochrome c reductase activities, does not bind to Blue-Agarose or Blue-Sepharose and exhibits a significantly lower molecular weight (177.000 vs. 241.000), whereas its kinetic characteristics and its sensitivity against several inhibitors and treatments are very similar to those of the terminal nitrate reductase activity of the wild strain complex. Spectral studies and antagonistic experiments with tungstate show the presence of cytochrome b557 and molybdenum. These facts lead us to propose that nitrate reductase from mutant 305 has a protein deletion which affects the pyridine nucleotide binding region of the diaphorase protein but without any effect on the terminal nitrate reductase activity.

On the theory of electron-transfer processes in aqueous solutions

1954 ◽  
Vol 222 (1148) ◽  
pp. 128-141 ◽  
Keyword(s):  
Electron Transfer ◽  
Point Of View ◽  
Complex Ions ◽  
Gaseous State ◽  
Biochemical Processes ◽  
Transfer Processes ◽  
Oxidation Reduction ◽  
Mechanical Interpretation ◽  
Electron Transfer Processes

It has been realized for some time that simple electron-transfer processes play an important part in the mechanism of many oxidation-reduction reactions in solution. An attempt has been made to give a quantum-mechanical interpretation of these processes on the basis of the earlier theories of electron transfer in the gaseous state (Landau 1932; Bates & Massey 1943). The present treatment for solutions takes into account the role of the solvent, with particular reference to the operation of the Franck—Condon principle and it also leads to some definite picture of the transition state for the electron transfer process. A number of examples are discussed, including electron transfer between like ions of different valency and also reactions involving complex ions, e.g. metal porphyrins, the reactions of which are of importance in certain biochemical processes. It appears that the application of certain theoretical principles leads to a satisfactory understanding of electron-transfer processes in solution from a qualitative and, in some cases, also from a semi-quantitative point of view.

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