Nickel and the metabolism of urea by Lemna paucicostata Hegelm. 6746

Gordon, William R.; Schwemmer, Susan S.; Hillman, William S.

doi:10.1007/bf00390258

Cited by 47 publications

(14 citation statements)

References 13 publications

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“…Gerendás and Sattelmacher (1997b) Carya illinoinensis (Pecan) Bai et al (2006aBai et al ( , b, 2007, Reilly et al (2006) Vigna unguiculata (Cowpeas) Eskew et al (1984) Lemna paucicostata (Water lentil) Gordon et al (1978) Lycopersicon esculentum (Tomato) Shimada et al (1980), Tan et al (2000) Brassica napus (Rapeseed) …”

Section: Role Of Nickel As a Micronutrientmentioning

confidence: 99%

Essential Roles and Hazardous Effects of Nickel in Plants

Ahmad

Ashraf²

2011

Reviews of Environmental Contamination and Toxicology

142

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With the world's ever increasing human population, the issues related to environmental degradation of toxicant chemicals are becoming more serious. Humans have accelerated the emission to the environment of many organic and inorganic pollutants such as pesticides, salts, petroleum products, acids, heavy metals, etc. Among different environmental heavy-metal pollutants, Ni has gained considerable attention in recent years, because of its rapidly increasing concentrations in soil, air, and water in different parts of the world. The main mechanisms by which Ni is taken up by plants are passive diffusion and active transport. Soluble Ni compounds are preferably absorbed by plants passively, through a cation transport system; chelated Ni compounds are taken up through secondary, active-transport-mediated means, using transport proteins such as permeases. Insoluble Ni compounds primarily enter plant root cells through endocytosis. Once absorbed by roots, Ni is easily transported to shoots via the xylem through the transpiration stream and can accumulate in neonatal parts such as buds, fruits, and seeds. The Ni transport and retranslocation processes are strongly regulated by metal-ligand complexes (such as nicotianamine, histidine, and organic acids) and by some proteins that specifically bind and transport Ni. Nickel, in low concentrations, fulfills a variety of essential roles in plants, bacteria, and fungi. Therefore, Ni deficiency produces an array of effects on growth and metabolism of plants, including reduced growth, and induction of senescence, leaf and meristem chlorosis, alterations in N metabolism, and reduced Fe uptake. In addition, Ni is a constituent of several metallo-enzymes such as urease, superoxide dismutase, NiFe hydrogenases, methyl coenzyme M reductase, carbon monoxide dehydrogenase, acetyl coenzyme-A synthase, hydrogenases, and RNase-A. Therefore, Ni deficiencies in plants reduce urease activity, disturb N assimilation, and reduce scavenging of superoxide free radical. In bacteria, Ni participates in several important metabolic reactions such as hydrogen metabolism, methane biogenesis, and acetogenesis. Although Ni is metabolically important in plants, it is toxic to most plant species when present at excessive amounts in soil and in nutrient solution. High Ni concentrations in growth media severely retards seed germinability of many crops. This effect of Ni is a direct one on the activities of amylases, proteases, and ribonucleases, thereby affecting the digestion and mobilization of food reserves in germinating seeds. At vegetative stages, high Ni concentrations retard shoot and root growth, affect branching development, deform various plant parts, produce abnormal flower shape, decrease biomass production, induce leaf spotting, disturb mitotic root tips, and produce Fe deficiency that leads to chlorosis and foliar necrosis. Additionally, excess Ni also affects nutrient absorption by roots, impairs plant metabolism, inhibits photosynthesis and transpiration, and causes ultrastructural modificat...

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Section: Role Of Nickel As a Micronutrientmentioning

confidence: 99%

Essential Roles and Hazardous Effects of Nickel in Plants

Ahmad

Ashraf²

2011

Reviews of Environmental Contamination and Toxicology

142

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“…Lemna species are known to be able to use either amino acids or urea as sole nitrogen sources under axenic laboratory conditions (9,12,14). Several of the transport systems described here must contribute to these capabilities.…”

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Uptake of Amino Acids and Other Organic Compounds by Lemna paucicostata Hegelm. 6746

Datko¹,

Mudd²

1985

Plant Physiol.

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A survey of the capacity of Lemna paucicostata to take up organic compounds such as might be present in the natural environment of this plant has identified eight discrete transport systems. Reciprocal inhibition studies defined the preferred substrates for these systems as follows: (a) neutral L-a-amino acids, (b) basic amino acids, (c) purine bases, (d) choline, (e) ethanolamine, (f) tyramine, (g) urea, and (h) aldohexoses. Each of these systems takes up its preferred substrates at high rates. At low concentrations, each Lemna frond during each minute takes up amounts which would be found in volumes ranging from 0.4 (tyramine) to 3.9 (urea) times its own volume. The two systems for amino acid transport both showed kinetics of the biphasic type, so that uptake by each can be described as the composite result of two Michaelis-Menten processes. The neutral amino acid system neither transports basic amino acids nor is inhibited by these compounds. The basic amino acid system does not transport neutral amino acids but is strongly inhibited by some, but not all, of these compounds. It is argued that the maintenance of these active, specific, and discrete systems in Lemna suggests they play important roles permitting this plant to utilize organic compounds occurring naturally in its environment.ascertain radiopurity. For many of the compounds studied, detection by ninhydrin (amines and amino acids), aniline-phthalate (carbohydrates), and UV fluorescence (adenine) allowed verification that the radiolabeled compound co-migrated with authentic unlabeled compound. Volatile acids were chromatographed as ammonium salts and fixed onto the paper as potassium salts for determination of radioactivity (16). The radiolabeled preparations co-migrated with authentic carrier and most contained little or no detectable radiocontaminants. Generally, those which contained more than 5% radiocontaminants were purified by preparative chromatography before use. L-[U-

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“…The biological significance of Ni recently has been discussed by Welch (15). Growth of soybean tissue cultures (16) and intact Lemna paucicostata (17) in media containing urea as the sole. source of nitrogen is greatly stimulated by Ni.…”

mentioning

confidence: 99%

Nickel: A micronutrient element for hydrogen-dependent growth of Rhizobium japonicum and for expression of urease activity in soybean leaves

Klucas

Hanus

Russell

et al. 1983

Proc. Natl. Acad. Sci. U.S.A.

115

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Soybean plants and Rhizobium japonicum 122 DES, a hydrogen uptake-positive strain, were cultured in media purified to remove Ni. Supplemental Ni had no significant effect on the dry matter or total N content of plants. However, the addition of Ni to both nitrate-grown and symbiotically grown plants resulted in a 7-to 10-fold increase in urease activity (urea amidohydrolase, EC 3.5.1.5) in leaves and significantly increased the hydrogenase activity (EC 1.18.3.1) in isolated nodule bacteroids. When cultured under chemolithotrophic conditions, free-living R. japonicum required Ni for growth and for the expression of hydrogenase activity. Hydrogenase activity was minimal or not detectable in cells incubated either without Ni or with Ni and chloramphenicol. Ni is required for derepression of hydrogenase activity and apparently protein synthesis is necessary for the participation of Ni in hydrogenase expression. The addition of Cr, V, Sn, and Pb in place of Ni failed to stimulate the activity of hydrogenase in R. japonhcum and urease in soybean leaves. The evidence indicates that Ni is an important micronutrient element in the biology of the soybean plant and R. japonicum.Nickel is an essential element in several biological processes, including H2 oxidation in some bacteria and urea hydrolysis by plants (1). Although its function is not completely understood, Ni is a constituent of urease (urea amidohydrolase, EC 3.5.1.5) from jackbean (2) and soybean (3) seeds, CO dehydrogenase from Clostridium thermoaceticum (4), and factor F4w from certain species of Methanobacterium (5, 6). Additionally, hydrogenases (EC 1.18.3.1) from Methanobacterium thermoautotrophicum (7), Alcaligenes eutrophus (8, 9), Desulfovibrio gigas (10), and Vibrio succinogenes (11) contain Ni, which appears to participate in an oxidation-reduction reaction during catalysis (10,12). Ni is a required micronutrient for the synthesis of functional hydrogenase in several other microorganisms (13,14) The potential importance of energy loss via H2 evolution from nitrogenase in nodules has been discussed in a review (19). H2 uptake via the hydrogenase system is important not only in bacteroids but also for chemolithotrophic growth of free-living rhizobia (20, 21). This study was conducted to determine whether the addition of Ni affected (i) the growth of soybean plants cultured either symbiotically or with nitrate, (ii) the expression of urease activity in soybean leaves, and (iii) the expression of hydrogenase activity in nodule bacteroids. In addition, we have examined the effect of adding Ni on the growth of and derepression of hydrogenase in R1. japonicum under chemolithotrophic conditions. MATERIALS AND METHODS Source of Chemicals. All chemicals, except otherwise indicated, were reagent grade and, as indicated below, some were purified to remove Ni. Fe, Co, Zn (as metals), MnCl2, CuCl2, PbF2, V205, SnO2, and Cr2O5 were Speepure grade and purchased directly from Johnson, Matthey (London) or through a United States supplier (Alfa-Ventron, Danvers,...

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Nickel and the metabolism of urea by Lemna paucicostata Hegelm. 6746

Cited by 47 publications

References 13 publications

Essential Roles and Hazardous Effects of Nickel in Plants

Essential Roles and Hazardous Effects of Nickel in Plants

Uptake of Amino Acids and Other Organic Compounds by Lemna paucicostata Hegelm. 6746

Nickel: A micronutrient element for hydrogen-dependent growth of Rhizobium japonicum and for expression of urease activity in soybean leaves

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