Influence of irradiation time and solution concentration on the photochemical degradation of EDDHA/Fe3+: effect of its photodecomposition products on soybean growth.

PubMed

Hernández-Apaolaza, Lourdes; Lucena, Juan J

2011-08-30

Ethylenediamine-N, N'-bis(2-hydroxyphenylacetic acid (EDDHA) is one of the most efficient iron-chelating agents employed to relieve iron chlorosis in plants. It has been well known for decades that this compound is photosensitive, but in spite of this fact its degradation pathways are virtually unknown. The aim of this work was to evaluate how the length of sunlight exposure and the concentration of irradiated EDDHA/Fe(3+) solutions influence the photostability of the chelate at constant pH. Moreover, the possible toxic effect of the chelate photodegradation products, elsewhere proposed, on soybean growth has been tested. The photodecomposition of the chelate increased as the time of sunlight exposure increased, and resulted in a partial decomposition of the organic ligand. Moreover, EDDHA/Fe(3+) photodecomposition was highly correlated with the concentration of solution exposed. Plants did not present differences in recovery from chlorosis among treatments with and without decomposition products. EDDHA/Fe(3+) undergoes photodegradation, like other aminopolycarboxylic acids, being more degraded as solution concentration decreases and exposure time increases. The photodecomposition products salicylic acid, salicylaldehide and Salicylaldehyde ethylenediamine diimine tested did not have negative effects on soybean growth, at least in the short-term hydroponic experimental design tested. Copyright © 2011 Society of Chemical Industry.

Characterization of commercial iron chelates and their behavior in an alkaline and calcareous soil.

PubMed

Cantera, Rodrigo G; Zamarreño, Angel M; García-Mina, José M

2002-12-18

Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time.

On the structure and spin states of Fe(III)-EDDHA complexes.

PubMed

Gómez-Gallego, Mar; Fernández, Israel; Pellico, Daniel; Gutiérrez, Angel; Sierra, Miguel A; Lucena, Juan J

2006-07-10

DFT methods are suitable for predicting both the geometries and spin states of EDDHA-Fe(III) complexes. Thus, extensive DFT computational studies have shown that the racemic-Fe(III) EDDHA complex is more stable than the meso isomer, regardless of the spin state of the central iron atom. A comparison of the energy values obtained for the complexes under study has also shown that high-spin (S = 5/2) complexes are more stable than low-spin (S = 1/2) ones. These computational results matched the experimental results of the magnetic susceptibility values of both isomers. In both cases, their behavior has been fitted as being due to isolated high-spin Fe(III) in a distorted octahedral environment. The study of the correlation diagram also confirms the high-spin iron in complex 2b. The geometry optimization of these complexes performed with the standard 3-21G* basis set for hydrogen, carbon, oxygen, and nitrogen and the Hay-Wadt small-core effective core potential (ECP) including a double-xi valence basis set for iron, followed by single-point energy refinement with the 6-31G* basis set, is suitable for predicting both the geometries and the spin-states of EDDHA-Fe(III) complexes. The presence of a high-spin iron in Fe(III)-EDDHA complexes could be the key to understanding their lack of reactivity in electron-transfer processes, either chemically or electrochemically induced, and their resistance to photodegradation.

Influence of the soil/solution ratio, interaction time, and extractant on the evaluation of iron chelate sorption/desorption by soils.

PubMed

Hernández-Apaolaza, Lourdes; Lucena, Juan J

2011-03-23

Synthetic Fe chelates are the most efficient agricultural practice to control Fe deficiency in crops, EDTA/Fe3+ and o,o-EDDHA/Fe3+ being the most commonly used. Their efficacy as Fe sources and carriers in soils can be severely limited by their retention on it. The aim of this work is to evaluate the possible bias introduced in the studies of the iron chelate retention by soils. For that purpose, results obtained for EDTA and EDDHA iron chelates from two batch studies with different soil/solution ratios were compared with data obtained for a leaching column experiment. Moreover, different extractants were tested to study the o,o-EDDHA/Fe3+ and o,p-EDDHA/Fe3+ desorption from a calcareous soil, and also the effect of the interaction time in their retention process has been evaluated. In summary, the mobility through a calcareous soil of the studied iron chelates differs greatly depending on the type of iron chelate and also on the procedure used to evaluate the retention and the soil/solution ratio used. In general, the leaching column method is preferred because the achieved conclusions are more representative of the natural conditions, but batch methods are very useful as a preliminary experiment, especially one with a high soil/solution ratio. The iron chelate desorption could be quantified by using a sequential extraction with water, sodium sulfate, and DTPA as extractants. Under the experimental conditions used in this study, o,o-EDDHA/Fe3+ retention increased with interaction time.

Effect of the tether on the Mg(II), Ca(II), Cu(II) and Fe(III) stability constants and pM values of chelating agents related to EDDHA.

PubMed

Sierra, Miguel A; Gómez-Gallego, Mar; Alcázar, Roberto; Lucena, Juan J; Yunta, Felipe; García-Marco, Sonia

2004-11-07

The effect of the length and the structure of the tether on the chelating ability of EDDHA-like chelates have not been established. In this work, PDDHA (propylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid), BDDHA (butylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid) and XDDHA (p-xylylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid) have been obtained and their chemical behaviour has been studied and compared with that of EDDHA following our methodology. The purity of the chelating agents, and their protonation, Ca(II), Mg(II), Fe(III) and Cu(II) stability constants and pM values have been determined. The stability constants and pM values indicate that EDDHA forms the most stable chelates followed by PDDHA. However, the differences among the pFe values are small when a nutrient solution is used, and in these conditions the XDDHA/Fe(III) chelate is the most stable. The results obtained in this work indicate that all the chelating agents studied can be used as iron chlorosis correctors and they can be applied to soil/plant systems.

In vitro and in vivo evaluation of potential aluminum chelators.

PubMed

Graff, L; Muller, G; Burnel, D

1995-10-01

The potential for aluminium (Al) chelation by different compounds was determined using 2 in vitro techniques. The formation of stable complexes with Al in an aqueous solution was evaluated using pulse polarography. This technique allowed the influence of temperature and calcium (Ca) to be studied for each compound. Certain compounds (EDDHA, HAES, citric acid and HBED) showed great chelation in the absence of Ca2+ at a temperature of 37 +/- 1 C. An ultrafiltration technique combined with Al determination by atomic emission spectroscopy allowed the efficiency of different substances to complex Al that were previously bound to serum proteins to be estimated. The kinetics of chelation and minimum efficient concentration have been determined for all products studied. EDDHA had chelation potential similar to DFO. The real efficacies of the compounds were studied in vivo to compare the effectiveness of repeated administrations of the best chelating agents (EDDHA, DFO, HAES and tartaric acid) on the distribution and excretion of Al after repeated i.p. administrations to rats. Intraperitoneal EDDHA significantly increased urinary metal (Al, Ca, Cu, Fe and Zn) excretion. These excretions may be correlated to a renal toxic potential property.

Chemical evaluation of HBED/Fe(3+) and the novel HJB/Fe(3+) chelates as fertilizers to alleviate iron chlorosis.

PubMed

López-Rayo, Sandra; Hernández, Diana; Lucena, Juan J

2009-09-23

Iron chelates such as ethylenediamine-N,N'-bis(2-hydroxyphenylacetic) acid (o,o-EDDHA) and their analogues are the most efficient soil fertilizers to treat iron chlorosis in plants growing in calcareous soil. A new chelating agent, HJB (N,N'-bis(2-hydroxy-5-methylphenyl)ethylendiamine-N,N'-diacetic acid) may be an alternative to o,o-EDDHA since its synthesis yields a purer product, but its chemical behavior and efficiency as chlorosis corrector should be evaluated. In this research, a known analogous HBED (N,N'-bis(2-hydroxyphenyl)ethylendiamine-N,N'-diacetic acid) has also been considered. First, an ion-pair high performance liquid chromatography (HPLC) method has been tested for the HJB/Fe(3+) and HBED/Fe(3+) determination. The ability of HJB and HBED to maintain Fe in solution has been compared with respect to o,o-EDDHA. Theoretical modelization for HBED and HJB in agronomic conditions has been done after the determination of the protonation and Ca(II), Mg(II), Fe(III), and Cu(II) stability constants for HJB. Also, batch interaction experiments with soils and soil materials have been conducted. According to our results, HJB/Fe(3+) and HBED/Fe(3+) present high stability, even when competing cations (Cu(2+), Ca(2+)) are present, and have low reactivity with soils and soil components. The chelating agent HJB dissolves a higher amount of Fe than o,o-EDDHA, and it seems as effective as o,o-EDDHA in keeping Fe in solution. These results indicate that these chelates may be very efficient products to correct Fe chlorosis, and additional plant experiments should demonstrate plants' ability to assimilate Fe from HJB/Fe(3+) and HBED/Fe(3+).

Phenolic aminocarboxylic acids as gallium-binding radiopharmaceuticals.

PubMed

Hunt, F C

1984-06-01

The phenolic aminocarboxylic acids ethylenediamine di [o-hydroxyphenylacetic acid] (EDDHA) and N,N'-bis [2-hydroxybenzyl] ethylenediamine N,N'-diacetic acid (HBED) form gallium complexes having high stability constants which enable them to resist exchange of gallium with plasma transferrin. 67Ga complexes were synthesized with these ligands, placing substituent groups in the phenolic ring to direct excretion via the renal or hepatobiliary route. The amount of 67Ga-Br-EDDHA excreted via the hepatobiliary route was comparable with that of some of the 99mTc agents. Excretion of 67Ga-Br-HBED was similar but with delayed transit from the liver. 67Ga COOH-EDDHA was excreted exclusively via the renal route. These findings provide a basis for developing new 67Ga or 68Ga radiopharmaceuticals, the latter for use in positron emission tomography, using these phenolic aminocarboxylates.

Obligatory reduction of ferric chelates in iron uptake by soybeans.

PubMed

Chaney, R L; Brown, J C; Tiffin, L O

1972-08-01

The contrasting Fe(2+) and Fe(3+) chelating properties of the synthetic chelators ethylenediaminedi (o-hydroxyphenylacetate) (EDDHA) and 4,7-di(4-phenylsulfonate)-1, 10-phenanthroline (bathophenanthrolinedisulfonate) (BPDS) were used to determine the valence form of Fe absorbed by soybean roots supplied with Fe(3+)-chelates. EDDHA binds Fe(3+) strongly, but Fe(2+) weakly; BPDS binds Fe(2+) strongly but Fe(3+) weakly. Addition of an excess of BPDS to nutrient solutions containing Fe(3+)-chelates inhibited soybean Fe uptake-translocation by 99+%; [Fe(II) (BPDS)(3)](4-) accumulated in the nutrient solution. The addition of EDDHA caused little or no inhibition. These results were observed with topped and intact soybeans. Thus, separation and absorption of Fe from Fe(3+)-chelates appear to require reduction of Fe(3+)-chelate to Fe(2+)-chelate at the root, with Fe(2+) being the principal form of Fe absorbed by soybean.

Chelating agents related to ethylenediamine bis(2-hydroxyphenyl)acetic acid (EDDHA): synthesis, characterization, and equilibrium studies of the free ligands and their Mg2+, Ca2+, Cu2+, and Fe3+ chelates.

PubMed

Yunta, Felipe; García-Marco, Sonia; Lucena, Juan J; Gómez-Gallego, Mar; Alcázar, Roberto; Sierra, Miguel A

2003-08-25

Iron chelates such as ethylenediamine-N,N'-bis(2-hydroxyphenyl)acetic acid (EDDHA) and their analogues are the most efficient soil fertilizers to treat iron chlorosis in plants growing in calcareous soils. EDDHA, EDDH4MA (ethylenediamine-N,N'-bis(2-hydroxy-4-methylphenyl)acetic acid), and EDDCHA (ethylenediamine-N,N'-bis(2-hydroxy-5-carboxyphenyl)acetic acid) are allowed by the European directive, but also EDDHSA (ethylenediamine-N,N'-bis(2-hydroxy-5-sulfonylphenyl)acetic acid) and EDDH5MA (ethylenediamine-N,N'-bis(2-hydroxy-5-methylphenyl)acetic acid) are present in several commercial iron chelates. In this study, these chelating agents as well as p,p-EDDHA (ethylenediamine-N,N'-bis(4-hydroxyphenyl)acetic acid) and EDDMtxA (ethylenediamine-N,N'-bis(2-metoxyphenyl)acetic acid) have been obtained following a new synthetic pathway. Their chemical behavior has been studied to predict the effect of the substituents in the benzene ring on their efficacy as iron fertilizers for soils above pH 7. The purity of the chelating agents has been determined using a novel methodology through spectrophotometric titration at 480 nm with Fe(3+) as titrant to evaluate the inorganic impurities. The protonation constants were determined by both spectrophotometric and potentiometric methods, and Ca(2+) and Mg(2+) stability constants were determined from potentiometric titrations. To establish the Fe(3+) and Cu(2+) stability constants, a new spectrophotometric method has been developed, and the results were compared with those reported in the literature for EDDHA and EDDHMA and their meso- and rac-isomers. pM values have been also determined to provide a comparable basis to establish the relative chelating ability of these ligands. The purity obtained for the ligands is higher than 87% in all cases and is comparable with that obtained by (1)H NMR. No significant differences have been found among ligands when their protonation and stability constants were compared. As expected, no Fe(3+) complexation was observed for p,p-EDDHA and EDDMtxA. The presence of sulfonium groups in EDDHSA produces an increase in acidity that affects their protonation and stability constants, although the pFe values suggest that EDDHSA could be also effective to correct iron chlorosis in plants.

Timing for a sustainable fertilisation of Glycine max by using HBED/Fe3+ and EDDHA/Fe3+ chelates.

PubMed

Martín-Fernández, Clara; López-Rayo, Sandra; Hernández-Apaolaza, Lourdes; Lucena, Juan J

2017-07-01

Efficient use of Fe chelates is crucial to avoid environmental risks and reduce economic losses. HBED/Fe 3+ has been recently approved by the European Union for soil fertilisation, but studies delving into the best timing for its application are necessary. In this work, a batch incubation experiment and two biological experiments were developed to determine the optimal physiological stage for a sustainable application of HBED/Fe 3+ in soil fertilisation compared with EDDHA/Fe 3+ fertilisers using 57 Fe. HBED/Fe 3+ demonstrated a high durability in soils and soil materials, maintaining more than 80% of Fe chelated after 70 days, and its application at an early physiological stage resulted in a high Fe accumulation in soybean and soil after 36 days. In contrast, the stability of EDDHA/Fe 3+ decreased because of the retention of its lowest stable isomers. The best timing for chelates application was confirmed in a 52 day experiment. The application of HBED/Fe 3+ at the early stage increased the Fe translocation to fruits; while o,o-EDDHA/Fe 3+ accumulated more Fe in fruits when added at the fructification stage. The high HBED/Fe 3+ stability in calcareous soil requires a differentiate application timing, and its addition at early physiological stages leads into the most efficient fertilisation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Zinc transformations in neutral soil and zinc efficiency in maize fertilization.

PubMed

Alvarez, Jose M; Gonzalez, Demetrio

2006-12-13

The effect of six Zn sources (Zn-phenolate, Zn-EDDHA, Zn-EDTA, Zn-lignosulfonate, Zn-polyflavonoid, and Zn-glucoheptonate) was studied by applying different Zn levels to a representative Calcic Haploxeralf neutral soil (the predominant clay is montmorillonite) in incubation and greenhouse experiments. Zinc soil behavior was evaluated by sequential DTPA and Mehlich-3 extraction procedures. In the incubation experiment, the highest percentage recovery values of Zn applied to soil occurred in the water-soluble plus exchangeable fraction (29%) in fertilization with 20 mg of Zn kg(-1) of Zn-EDTA fertilizer. In the greenhouse experiment with maize (Zea mays L.), a comparison of different Zn carriers showed that the application of six fertilizers did not significantly increase the plant dry matter yield among fertilizer treatments. The highest yield occurred when 20 mg of Zn kg(-1) was applied as Zn-EDDHA fertilizer (79.4 g per pot). The relative effectiveness of the Zn sources in increasing Zn concentration in plants was in the following order: Zn-EDTA (20 mg kg(-1)) > Zn-EDDHA (20 mg kg(-1)) approximately Zn-EDTA (10 mg kg(-1)) > Zn-EDDHA (10 mg kg(-1)) approximately Zn-phenolate (both rates) approximately Zn-polyflavonoid (both rates) approximately Zn-lignosulfonate (both rates) approximately Zn-glucoheptonate (both rates) > untreated Zn. The highest amounts of Zn taken up by the plants occurred when Zn was applied as Zn-EDTA fertilizer (20 mg kg(-1), 7.44 mg of Zn per pot; 10 mg kg(-1) Zn rate, 3.93 mg of Zn per pot) and when Zn was applied as Zn-EDDHA fertilizer (20 mg kg(-1) Zn rate, 4.66 mg Zn per pot). After the maize crop was harvested, sufficient quantities of available Zn remained in the soil (DTPA- or Mehlich-3-extractable Zn) for another harvest.

Foliar applications of iron promote flavonoids accumulation in grape berry of Vitis vinifera cv. Merlot grown in the iron deficiency soil.

PubMed

Shi, Pengbao; Song, Changzheng; Chen, Haiju; Duan, Bingbing; Zhang, Zhenwen; Meng, Jiangfei

2018-07-01

Flavonoids are important compounds for grape and wine quality. Foliar fertilization with iron compounds has been reported to have a substantial impact on grape composition in the grapevines growing in calcareous soil. However, much less is known about its real impact on flavonoid composition. In the present study, Ferric ethylenediamine di (O-hydroxyphenylacetic) acid (Fe-EDDHA) was foliar applied to Merlot (Vitis vinifera L.) grapevines growing in calcareous soil over two consecutive vintages in order to study its effect on grape flavonoid composition. Fe-EDDHA foliar supply tended to increase grape sugar, anthocyanin and flavonol content, decrease acid content and enhance the juice pH when compared to the control. Principal component analysis showed that the vintage also had influence on grape quality. The results suggested that Fe-EDDHA foliar application had an enhancement effect on grape secondary metabolism, and the effect increased the nutritional value of the consequent grapes and wines. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessment of potential aluminum chelators in an octanol/aqueous system and in the aluminum-loaded rabbit.

PubMed

Yokel, R A; Kostenbauder, H B

1987-11-01

Aluminum (Al) solubilization from Al borate and its distribution in an octanol/aqueous system (Do/w) were determined in the absence and presence of 12 potential Al chelators. Citrate, N,N'-bis-(2-hydroxybenzyl)ethylenediamine- N,N'-diacetic acid (HBED), cyclohexane-1,2-diaminotetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), desferrioxamine, and ethylenediamine-N,N'-bis(2-dihydroxyphenylacetic acid) (EDDHA) were 55 to over 100% efficient in solubilizing equimolar amounts of Al. Tetracycline, EDTA, and 2,3-dihydroxybenzoic acid (DHBA) were less than 20% efficient. 1,4-Dioxane and fluoride were ineffective. The Do/w of Al averaged 0.005. The Do/w of the Al.chelator complex was generally less than that of Al, except for HBED and tetracycline (0.04 and 0.96, respectively). The Do/w of DHBA, desferrioxamine, EDDHA, and HBED were not influenced by Al, but tetracycline became more lipophilic. These compounds were tested for their ability to increase urinary Al excretion in Al-loaded rabbits. Chelators were given po weekly beginning 2 weeks after Al loading. Urine was obtained hourly from 3 hr prior to 6 hr after chelator administration and analyzed for Al. Fluoride and tetracycline (450 and 4500 mumol/kg) and citrate, NTA, EDTA, CDTA, DTPA, DHBA, HBED, and 1,4-dioxane (150 and 1500 mumol/kg) were ineffective. Following HBED administration, some of the Al-loaded rabbits died, presumably due to redistribution of Al within the rabbit. Following DTPA administration, some of the Al-loaded rabbits died, presumably due to DTPA. Oral EDDHA (1500 mumol/kg) significantly increased urinary Al excretion. EDDHA and desferrioxamine (150 mumol/kg) were administered by po, sc, and iv routes and were found to have comparable potency. The in vitro results may explain some of the in vivo findings. The in vitro methods may be useful to screen out compounds with no chelation potential. EDDHA-like compounds may have potential as alternatives to desferrioxamine in the prevention or treatment of Al accumulation and Al-induced toxicity.

Efficiency of a new strategy involving a new class of natural hetero-ligand iron(III) chelates (Fe(III)-NHL) to improve fruit tree growth in alkaline/calcareous soils.

PubMed

Fuentes, Marta; Ortuño, María F; Pérez-Sarmiento, Francisco; Bacaicoa, Eva; Baigorri, Roberto; Conejero, Wenceslao; Torrecillas, Arturo; García-Mina, José M

2012-12-01

Iron (Fe) chlorosis is a serious problem affecting the yield and quality of numerous crops and fruit trees cultivated in alkaline/calcareous soils. This paper describes the efficiency of a new class of natural hetero-ligand Fe(III) chelates (Fe-NHL) to provide available Fe for chlorotic lemon trees grown in alkaline/calcareous soils. These chelates involve the participation in the reaction system of a partially humified lignin-based natural polymer and citric acid. First results showed that Fe-NHL was adsorbed on the soil matrix while maintaining available Fe for plants in alkaline/calcareous solution. The effects of using three different sources as Fe fertilisers were also compared: two Fe-NHL formulations (NHL1, containing 100% of Fe as Fe-NHL, and NHL2, containing 80% of Fe as Fe-NHL and 20% of Fe as Fe-ethylenediamine-N,N'-bis-(o-hydroxyphenylacetic) acid (Fe-EDDHA)) and Fe-EDDHA. Both Fe-NHL formulations increased fruit yield without negative effects on fruit quality in comparison with Fe-EDDHA. In the absence of the Fe-starter fraction (NHL1), trees seemed to optimise Fe assimilation and translocation from Fe-NHL, directing it to those parts of the plant more involved in development. The field assays confirmed that Fe-NHL-based fertilisers are able to provide Fe to chlorotic trees, with results comparable to Fe-EDDHA. Besides, this would imply a more sustainable and less expensive remediation than synthetic chelates. Copyright © 2012 Society of Chemical Industry.

Labeling of monoclonal antibodies with a 67Ga-phenolic aminocarboxylic acid chelate. Part I. Chemistry and labeling technique.

PubMed

Schuhmacher, J; Matys, R; Hauser, H; Maier-Borst, W; Matzku, S

1986-01-01

As a chelating agent for labeling antibodies (Abs) with metallic radionuclides, a propionic acid substituted ethylenediamine N,N'-di-[(o-hydroxyphenyl) acetic acid] (P-EDDHA), which tightly complexes 67Ga, was synthesized. The 67Ga-P-EDDHA chelate was coupled in aqueous solution to IgG at a molar ratio of 1:1 via carbodiimide. The average coupling yield was 15%. A specific activity of 4 mCi/mg IgG could be obtained with commercially supplied 67Ga. In vitro stability was evaluated in human serum at 37 degrees C and showed a half-life of about 120 h for the release of 67Ga from the labeled Ab during the initial phase of incubation. This in vitro halflife is similar to that measured for 111In-DTPA labeled Abs. Because of the high stability of the 67Ga-P-EDDHA chelate, the in vivo formation of radioactive labeled transferrin by transchelation, as described for 111In-DTPA labeled Abs, should, however, be reduced by this labeling technique.

Effectiveness of FeEDDHA, FeEDDHMA, and FeHBED in Preventing Iron-Deficiency Chlorosis in Soybean.

PubMed

Bin, Levi M; Weng, Liping; Bugter, Marcel H J

2016-11-09

The performance of FeHBED in preventing Fe deficiency chlorosis in soybean (Glycine max (L.) Merr.) in comparison to FeEDDHA and FeEDDHMA was studied, as well as the importance of the ortho-ortho and ortho-para/rest isomers in defining the performance. To this end, chlorophyll production (SPAD), plant dry matter yield, and the mass fractions of important mineral elements in the plant were quantified in a greenhouse pot experiment. All three Fe chelates increased SPAD index and dry matter yield compared to the control. The effect of FeHBED on chlorophyll production was visible over a longer time span than that of FeEDDHA and FeEDDHMA. Additionally, FeHBED did not suppress Mn uptake as much as the other Fe chelates. Compared to the other Fe chelates, total Fe content in the young leaves was lower in the FeHBED treatment; however, total Fe content was not directly related to chlorophyll production and biomass yield. For each chelate, the ortho-ortho isomer was found to be more effective than the other isomers evaluated.

CE of phytosiderophores and related metal species in plants.

PubMed

Xuan, Yue; Scheuermann, Enrico B; Meda, Anderson R; Jacob, Peter; von Wirén, Nicolaus; Weber, Günther

2007-10-01

Phytosiderophores (PS) and the closely related substance nicotianamine (NA) are key substances in metal uptake into graminaceous plants. Here, the CE separation of these substances and related metal species is demonstrated. In particular, the three PS 2'-deoxymugineic acid (DMA), mugineic acid (MA), and 3-epi-hydroxymugineic acid (epi-HMA), and NA, are separated using MES/Tris buffer at pH 7.3. Moreover, three Fe(III) species of the different PS are separated without any stability problems, which are often present in chromatographic analyses. Also divalent metal species of Cu, Ni, and Zn with the ligands DMA and NA are separated with the same method. By using a special, zwitterionic CE capillary, even the separation of two isomeric Fe(III) chelates with the ligand ethylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid (EDDHA) is possible (i.e., meso-Fe(III)-EDDHA and rac-Fe(III)-EDDHA), and for fast separations of NA and respective divalent and trivalent metal species, a polymer CE microchip with suppressed EOF is described. The proposed CE method is applicable to real plant samples, and enables to detect changes of metal species (Cu-DMA, Ni-NA), which are directly correlated to biological processes.

Novel chelating agents for iron, manganese, zinc, and copper mixed fertilisation in high pH soil-less cultures.

PubMed

López-Rayo, Sandra; Nadal, Paloma; Lucena, Juan J

2016-03-15

Studies about simultaneous fertilisation with several micronutrients have increased in recent years, as Fe, Mn and Zn deficiencies may appear in the same culture conditions. In fertigation, the replacement of sulfates by synthetic chelates is essential in areas with high pH irrigation water and substrates. Ethylenediamine-N-(2-hydroxyphenylacetic acid)-N'-(4-hydroxyphenylacetic acid) (o,p-EDDHA) and ethylenediamine disuccinic acid (EDDS) are novel chelating agents whose efficacy in simultaneous fertilisation of Zn, Mn and Cu is unknown. This work evaluates the effectiveness of both ligands compared to traditional ligands (EDTA, HEEDTA and DTPA) applied as micronutrient chelate mixtures to soybean and navy bean plants grown in soil-less cultures at high pH by analysing the SPAD and micronutrient nutritional status, including the Composition Nutritional Diagnosis (CND) analysis tool. The application of micronutrients using o,p-EDDHA was more effective in providing Mn and Zn than traditional ligands or sulfates. The application using EDDS increased the Zn nutrition. The results are well correlated with the chemical stability of the formulations. The combined application of Mn and Zn as o,p-EDDHA chelates can represent a more effective source than traditional chelates in micronutrient fertiliser mixtures in soil-less cultures at a high pH. © 2015 Society of Chemical Industry.

Characterization and quantification of racemic and meso-ethylenediamine-N,N'-bis(2-hydroxy-5-sulfophenylacetic) acid/iron (III) by ion-pair ultra-high performance liquid chromatography coupled with diode array detector and electrospray tandem mass spectrometry.

PubMed

Biasone, Alessandro; Cianci, Giusto; Di Tommaso, Donata; Piaggesi, Alberto; Tagliavini, Emilio; Galletti, Paola; Moretti, Fabio

2013-03-22

EDDHSA/Fe is a promising substitute of EDDHA/Fe to fight iron chlorosis. o,o-EDDHSA structure contains two chiral carbons giving the racemic and meso couples of stereoisomers. Ion-pair HPLC and UHPLC-UV/Vis-ESI-MS/MS methods were developed for the determination of racemic and meso-o,o-EDDHSA/Fe in commercial samples of chelates. The lack of a commercial EDDHSA standard was overcome by sulfonation of a commercial available o,o-EDDHA standard and subsequent quantification by (1)H-NMR. Assignment of configurations was carried out starting from racemic and meso-o,o-EDDHA/Fe by direct sulfonation to give the corresponding o,o-EDDHSA/Fe isomers. The performances of these methods were assessed in terms of intra and inter-day precision, linearity and selectivity. The high selectivity and lower detection limit (nanomolar) of the UHPLC-ESI-MS/MS method could allow to deepen the knowledge relative to meso and rac-o,o-EDDHSA/Fe interactions with plants, its fate in different soil conditions, its mobility and other environmental aspects. Copyright © 2013 Elsevier B.V. All rights reserved.

Possible role of jasmonic acid in the regulation of floral induction, evocation and floral differentiation in Lemna minor L.

PubMed

Krajncic, B; Kristl, J; Janzekovic, I

2006-01-01

Jasmonic acid (JA) is implicated in a wide variety of developmental and physiological processes in plants. Here, we studied the effects of JA and the combination of JA and ethylenediamine-dio-hydroxyphenyl-acetic acid (EDDHA) on flowering in Lemna minor in axenical cultures. JA (0.475-47.5 nmol l(-1)) enhanced floral induction in L. minor under long-day (LD) conditions. Under the same conditions, at a concentration of 237.5 nmol l(-1), JA inhibited floral induction, and at a concentration of 475 nmol l(-1) it prevented floral induction. Under LD conditions with LD preculture, a combination of EDDHA (20,500 nmol l(-1)) and JA (47.5 nmol l(-1)) had a synergistic effect on the promotion of floral induction. Floral induction was enhanced to the greatest extent in experiments with LD precultures. Microscopic examination of microphotographs of histological sections showed that JA and, to an even greater extent, JA+EDDHA at optimal concentrations promote apical floral induction (evocation). Furthermore, JA, and to an even greater extent JA in combination with EDDHA in an optimal concentration, also promote flower differentiation, especially the development of stamens, as is evident from the microphotographs. The experimental results show that JA promotes floral induction in other species of Lemnaceae from various groups according to their photoperiodic response. The results support our hypothesis that, in addition to previously ascribed functions, JA may regulate floral induction, evocation and floral differentiation. Our hypothesis is supported also by the results obtained by quantitative determination of endogenous JA levels in L. minor at three growth stages. The levels of endogenous JA decreased from 389 ng JA g(-1) (fresh weight) of L. minor during the vegetative stage to 217 ng JA g(-1) during the evocation stage, and to 37.5 ng JA g(-1) during the flowering stage, which proves that JA is used for flowering.

Mechanism for iron control of the Vibrio fischeri luminescence system: involvement of cyclic AMP and cyclic AMP receptor protein and modulation of DNA level.

PubMed

Dunlap, P V

1992-07-01

Iron controls luminescence in Vibrio fischeri by an indirect but undefined mechanism. To gain insight into that mechanism, the involvement of cyclic AMP (cAMP) and cAMP receptor protein (CRP) and of modulation of DNA levels in iron control of luminescence were examined in V. fischeri and in Escherichia coli containing the cloned V. fischeri lux genes on plasmids. For V. fischeri and E. coli adenylate cyclase (cya) and CRP (crp) mutants containing intact lux genes (luxR luxICDABEG), presence of the iron chelator ethylenediamine-di(o-hydroxyphenyl acetic acid) (EDDHA) increased expression of the luminescence system like in the parent strains only in the cya mutants in the presence of added cAMP. In the E. coli strains containing a plasmid with a Mu dl(lacZ) fusion in luxR, levels of beta-galactosidase activity (expression from the luxR promoter) and luciferase activity (expression from the lux operon promoter) were both 2-3-fold higher in the presence of EDDHA in the parent strain, and for the mutants this response to EDDHA was observed only in the cya mutant in the presence of added cAMP. Therefore, cAMP and CRP are required for the iron restriction effect on luminescence, and their involvement in iron control apparently is distinct from the known differential control of transcription from the luxR and luxICDABEG promoters by cAMP-CRP. Furthermore, plasmid and chromosomal DNA levels were higher in E. coli and V. fischeri in the presence of EDDHA. The higher DNA levels correlated with an increase in expression of chromosomally encoded beta-galactosidase in E. coli and with a higher level of autoinducer in cultures of V. fischeri. These results implicate cAMP-CRP and modulation of DNA levels in the mechanism of iron control of the V. fischeri luminescence system.

Determination of synthetic ferric chelates used as fertilizers by liquid chromatography-electrospray/mass spectrometry in agricultural matrices.

PubMed

Alvarez-Fernández, Ana; Orera, Irene; Abadía, Javier; Abadía, Anunciación

2007-01-01

A high-performance liquid chromatography-electrospray ionization/mass spectrometry (time of flight) method has been developed for the simultaneous determination of synthetic Fe(III)-chelates used as fertilizers. Analytes included the seven major Fe(III)-chelates used in agriculture, Fe(III)-EDTA, Fe(III)-DTPA, Fe(III)-HEDTA, Fe(III)-CDTA, Fe(III)-o,oEDDHA, Fe(III)-o,pEDDHA, and Fe(III)-EDDHMA, and the method was validated using isotope labeled (57)Fe(III)-chelates as internal standards. Calibration curves had R values in the range 0.9962-0.9997. Limits of detection and quantification were in the ranges 3-164 and 14-945 pmol, respectively. Analyte concentrations could be determined between the limits of quantification and 25 muM (racemic and meso Fe(III)-o,oEDDHA and Fe(III)-EDDHMA) or 50 muM (Fe(III)-EDTA, Fe(III)-HEDTA, Fe(III)-DTPA, Fe(III)-CDTA and Fe(III)-o,pEDDHA). The average intraday repeatability values were approximately 0.5 and 5% for retention time and peak area, respectively, whereas the interday repeatability values were approximately 0.7 and 8% for retention time and peak area, respectively. The method was validated using four different agricultural matrices, including nutrient solution, irrigation water, soil solution, and plant xylem exudates, spiked with Fe(III)-chelate standards and their stable isotope-labeled corresponding chelates. Analyte recoveries found were in the ranges 92-101% (nutrient solution), 89-102% (irrigation water), 82-100% (soil solution), and 70-111% (plant xylem exudates). Recoveries depended on the analyte, with Fe(III)-EDTA and Fe(III)-DTPA showing the lowest recoveries (average values of 87 and 88%, respectively, for all agricultural matrices used), whereas for other analytes recoveries were between 91 and 101%. The method was also used to determine the real concentrations of Fe(III)-chelates in commercial fertilizers. Furthermore, the method is also capable of resolving two more synthetic Fe(III)-chelates, Fe(III)-EDDHSA and Fe(III)-EDDCHA, whose exact quantification is not currently possible because of lack of commercial standards.

Studies on the growth and flowering of a short-day plant, Wolffia microscopica : II. Role of metal ions and chelates.

PubMed

Seth, P N; Venkataraman, R; Maheshwari, S C

1970-12-01

As found earlier, supply of EDTA was obligatory for both flowering and satisfactory vegetative growth in Wolffia microscopica. It is now shown that the metal affecting growth and flowering is most probably iron. Omission of Fe but not of Cu, Zn, Mn and B from the medium markedly affects vegetative growth. There exists also a strong interaction between EDTA and Fe, one being largely inactive in the absence of the other. When Fe-EDDHA is substituted for Fe-citrate and EDTA in the medium, no great effect is seen in vegetative growth, but flowering takes place even under continuous light. Studies with (59)Fe show that, in the medium containing Fe-EDDHA, Fe uptake is stimulated several-fold; this is apparently associated with the flowering condition.

Iron plaque formed under aerobic conditions efficiently immobilizes arsenic in Lupinus albus L roots.

PubMed

Fresno, Teresa; Peñalosa, Jesús M; Santner, Jakob; Puschenreiter, Markus; Prohaska, Thomas; Moreno-Jiménez, Eduardo

2016-09-01

Arsenic is a non-threshold carcinogenic metalloid. Thus, human exposure should be minimised, e.g. by chemically stabilizing As in soil. Since iron is a potential As immobiliser, it was investigated whether root iron plaque, formed under aerobic conditions, affects As uptake, metabolism and distribution in Lupinus albus plants. White lupin plants were cultivated in a continuously aerated hydroponic culture containing Fe/EDDHA or FeSO4 and exposed to arsenate (5 or 20 μM). Only FeSO4 induced surficial iron plaque in roots. LA-ICP-MS analysis accomplished on root sections corroborated the association of As to this surficial Fe. Additionally, As(V) was the predominant species in FeSO4-treated roots, suggesting less efficient As uptake in the presence of iron plaque. Fe/EDDHA-exposed roots neither showed such surficial FeAs co-localisation nor As(V) accumulation; in contrast As(III) was the predominant species in root tissue. Furthermore, FeSO4-treated plants showed reduced shoot-to-root As ratios, which were >10-fold lower compared to Fe/EDDHA treatment. Our results highlight the role of an iron plaque formed in roots of white lupin under aerobic conditions on As immobilisation. These findings, to our knowledge, have not been addressed before for this plant and have potential implications on soil remediation (phytostabilisation) and food security (minimising As in crops). Copyright © 2016 Elsevier Ltd. All rights reserved.

Enterobactin-mediated iron transport in Pseudomonas aeruginosa.

PubMed Central

Poole, K; Young, L; Neshat, S

1990-01-01

A pyoverdine-deficient strain of Pseudomonas aeruginosa was unable to grow in an iron-deficient minimal medium in the presence of the nonmetabolizable iron chelator ethylene diamine-di(omega-hydroxyphenol acetic acid) (EDDHA), although addition of enterobactin to EDDHA-containing minimal media did restore growth of the pyoverdine-deficient P. aeruginosa. Consistent with the apparent ability of enterobactin to provide iron to P. aeruginosa, enterobactin-dependent 55Fe3+ uptake was observed in cells of P. aeruginosa previously grown in an iron-deficient medium containing enterobactin (or enterobactin-containing Escherichia coli culture supernatant). This uptake was energy dependent, was observable at low concentrations (60 nM) of FeCl3, and was absent in cells cultured without enterobactin. A novel protein with a molecular weight of approximately 80,000 was identified in the outer membranes of cells grown in iron-deficient minimal medium containing enterobactin, concomitant with the induction of enterobactin-dependent iron uptake. A Tn501 insertion mutant lacking this protein was isolated and shown to be deficient in enterobactin-mediated iron transport at 60 nM FeCl3, although it still exhibited enterobactin-dependent growth in iron-deficient medium containing EDDHA. It was subsequently observed that the mutant was, however, capable of enterobactin-mediated iron transport at much higher concentrations (600 nM) of FeCl3. Indeed, enterobactin-dependent iron uptake at this concentration of iron was observed in both the mutant and parent strains irrespective of whether they had been cultured in the presence of enterobactin.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2174865

Effects of iron(III)chelates on the solubility of heavy metals in calcareous soils.

PubMed

Ylivainio, Kari

2010-10-01

In this study I evaluated the effects of complexing agents on the solubility of heavy metals in an incubation experiment up to 56 days when complexing agents were applied as Fe-chelates (Fe-EDDS(S,S), Fe-EDDS(mix), Fe-EDTA and Fe-EDDHA) on calcareous soils at a level sufficient to correct Fe chlorosis (0.1 mmol kg(-1)). Of these ligands, EDDHA was the most efficient in keeping Fe in water-soluble form, and EDDS increased the solubility of Cu and Zn most, and only EDTA increased the solubility of Cd and Pb. EDTA increased the solubility of Ni steadily during the incubation period, equalling about 5-8% of the added EDTA concentration. [S,S]-EDDS was biodegraded within 56 days, whereas EDDS(mix) was less biodegradable. Ni-chelates were the most recalcitrant against biodegradation. The study shows that even a moderate input of chelates to soil increases the solubility of toxic heavy metals and their risk of leaching. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Potential of ethylenediaminedi(o-hydroxyphenylacetic acid) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid for the determination of metal ions by capillary electrophoresis.

PubMed

Krokhin, O V; Kuzina, O V; Hoshino, H; Shpigun, O A; Yotsuyanagi, T

2000-08-25

Two aromatic polyaminocarboxylate ligands, ethylenediaminedi(o-hydroxyphenylacetic acid) (EDDHA) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED), were applied for the separation of transition and heavy metal ions by the ion-exchange variant of electrokinetic chromatography. EDDHA structure contains two chiral carbon centers. It makes it impossible to use the commercially available ligand. All the studied metal ions showed two peaks, which correspond to meso and rac forms of the ligand. The separation of metal-HBED chelates was performed using poly(diallyldimethylammonium) polycations in mixed acetate-hydroxide form. Simultaneous separation of nine single- and nine double-charged HBED chelates, including In(III), Ga(III), Co(II)-(III) and Mn(II)-(III) pairs demonstrated the efficiency of 40,000-400,000 theoretical plates. The separation of Co(III), Fe(III) complexes with different arrangements of donor groups and oxidation of Co(II), Mn(H), Fe(II) ions in reaction with HBED have been discussed.

Influence of FeEDDS, FeEDTA, FeDTPA, FeEDDHA, and FeSO4 on Marigold Growth and Nutrition, and Substrate and Runoff Chemistry

USDA-ARS?s Scientific Manuscript database

Objectives of the study were to determine effects of Fe source on plant growth, plant nutrition, substrate chemistry and runoff chemistry. Iron source (FS) treatments consisted of Fe-aminopolycarboxylic acid (APCA) complexones iron ethylenediaminetetraacetic acid (FeEDTA), iron [S, S']-ethylenediam...

Labeling of monoclonal antibodies with a 67Ga-phenolic aminocarboxylic acid chelate. Part II. Comparison of immunoreactivity and biodistribution of monoclonal antibodies labeled with the 67Ga-chelate or with 131I.

PubMed

Matzku, S; Schuhmacher, J; Kirchgessner, H; Brüggen, J

1986-01-01

Coupling of the 67Ga-P-EDDHA chelate via carbodiimide to the anti-melanoma monoclonal antibody (Mab) M.2.9.4 resulted in a low degree of oligomerization, but a considerable degree of intra-molecular (inter-chain) cross-linking. However, this did not impair immunoreactivity, nor did the half-life in vivo differ substantially from that of 131I-M.2.9.4. Biodistribution analysis in normal mice showed Ga:I ratios near 1 in the blood and other tissues not involved in degradation and label excretion. In tissues of the reticulo-endothelial system (RES) and the kidneys, Ga:I ratios up to 2.51 were reached within 4 days of administration. In antigen-positive MeWo tumor tissue, retention of 67Ga also excreted that of 131I, so that tumor; organ ratios (except tumor:liver) were superior for the 67Ga-labeled MAb. It is concluded that the method of coupling pre-established 67Ga-P-EDDHA chelate to antibody results in a functionally intact tracer molecule, whose persistence in vivo is not significantly impaired. The major difference to I-labeled MAbs may be a prolonged retention of Ga in tissues (cells) physiologically involved in antibody catabolism.

Evaluation of different iron compounds in chlorotic Italian lemon trees (Citrus lemon).

PubMed

Ortiz, Patricio Rivera; Castro Meza, Blanca I; de la Garza Requena, Francisco R; Flores, Guillermo Mendoza; Etchevers Barra, Jorge D

2007-05-01

The severe deficiency of iron or ferric chlorosis is a serious problem of most citrus trees established in calcareous soils, as a result of the low availability of iron in these soils and the poor uptake and limited transport of this nutrient in trees. The objective of this study was to evaluate the response of chlorotic Italian lemon trees (Citrus lemon) to the application of iron compounds to roots and stems. On comparing the effects of aqueous solutions of ferric citrate, ferrous sulphate and FeEDDHA chelate, applied to 20% of the roots grown in soil and sand, of trees that were planted in pots containing calcareous soil, it was observed that the chelate fully corrected ferric chlorosis, while citrate and sulphate did not solve the problem. EDDHA induced the root uptake of iron as well as the movement of the nutrient up to the leaves. With the use of injections of ferric solutions into the secondary stem of adult trees, ferric citrate corrected chlorosis but ferrous sulphate did not. The citrate ion expanded the mobility of iron within the plant, from the injection points up to the leaves, whereas the sulphate ion did not sufficiently improve the movement of iron towards the leaf mesophyll.

Effect of Iron Availability on Induction of Systemic Resistance to Fusarium Wilt of Chickpea by Pseudomonas spp.

PubMed

Saikia, Ratul; Srivastava, Alok K; Singh, Kiran; Arora, Dilip K; Lee, Min-Woong

2005-03-01

Selected isolates of Pseudomonas fluorescens (Pf4-92 and PfRsC5) and P. aeruginosa (PaRsG18 and PaRsG27) were examined for growth promotion and induced systemic resistance against Fusarium wilt of chickpea. Significant increase in plant height was observed in Pseudomonas treated plants. However, plant growth was inhibited when isolates of Pseudomonas were used in combination with Fusarium oxysporum f. sp. ciceri (FocRs1). It was also observed that the Pseudomonas spp. was colonized in root of chickpea and significantly suppressed the disease in greenhouse condition. Rock wool bioassay technique was used to study the effect of iron availability on the induction of systemic resistance to Fusarium wilt of chickpea mediated by the Pseudomonas spp. All the isolates of Pseudomonas spp. showed greater disease control in the induced systemic resistance (ISR) bioassay when iron availability in the nutrient solution was low. High performance liquid chromatography (HPLC) analysis indicated that all the bacterial isolates produced more salicylic acid (SA) at low iron (10µM EDDHA) than high iron availability (10µFe(3+) EDDHA). Except PaRsG27, all the three isolates produced more pseudobactin at low iron than high iron availability.

Effect of Iron Availability on Induction of Systemic Resistance to Fusarium Wilt of Chickpea by Pseudomonas spp.

PubMed Central

Saikia, Ratul; Srivastava, Alok K.; Singh, Kiran; Lee, Min-Woong

2005-01-01

Selected isolates of Pseudomonas fluorescens (Pf4-92 and PfRsC5) and P. aeruginosa (PaRsG18 and PaRsG27) were examined for growth promotion and induced systemic resistance against Fusarium wilt of chickpea. Significant increase in plant height was observed in Pseudomonas treated plants. However, plant growth was inhibited when isolates of Pseudomonas were used in combination with Fusarium oxysporum f. sp. ciceri (FocRs1). It was also observed that the Pseudomonas spp. was colonized in root of chickpea and significantly suppressed the disease in greenhouse condition. Rock wool bioassay technique was used to study the effect of iron availability on the induction of systemic resistance to Fusarium wilt of chickpea mediated by the Pseudomonas spp. All the isolates of Pseudomonas spp. showed greater disease control in the induced systemic resistance (ISR) bioassay when iron availability in the nutrient solution was low. High performance liquid chromatography (HPLC) analysis indicated that all the bacterial isolates produced more salicylic acid (SA) at low iron (10µM EDDHA) than high iron availability (10µFe3+ EDDHA). Except PaRsG27, all the three isolates produced more pseudobactin at low iron than high iron availability. PMID:24049472

Chelation in metal intoxication. VIII. Removal of chromium from organs of potassium chromate administered rats.

PubMed

Behari, J R; Tandon, S K

1980-03-01

Some polyaminocarboxylic acids were examined for their ability to mobilize chromium from certain vital organs, their subcellular fractions, and blood cells of potassium chromate administered rats. Hexamethylene 1,6-diamino tetraacetic acid (TDTA), triethylene tetramine hexaacetic acid (TTHA), and ethylene diamine di (O-hydroxylphenyl acetic acid) (EDDHA) may be useful in preventing or reducing chromate toxicity. No definite relationship could be observed between the structure of the chelating agents and their chromium-removing capacity.

Zinc transformations in acidic soil and zinc efficiency on maize by adding six organic zinc complexes.

PubMed

López-Valdivia, L M; Fernández, M D; Obrador, A; Alvarez, J M

2002-03-13

Experiments under laboratory and greenhouse conditions were conducted to study the response of maize (Zea mays L.) to Zn fertilizer applications (Zn-phenolate, Zn-EDDHA, Zn-EDTA, Zn-lignosulfonate, Zn-polyflavonoid, and Zn-heptagluconate) in an Aquic Haploxeralf soil. The application of Zn complexes significantly increased Zn uptake by the plant compared with that in the control soil. The highest enhancements were obtained in soil treated with Zn-EDTA, Zn-lignosulfonate, and Zn-EDDHA. The highest percentages of Zn taken up by the plants occurred when 20 mg x kg(-1) Zn was applied as Zn-EDTA fertilizer and 10 mg x kg(-1) as Zn-lignosulfonate fertilizer. In the greenhouse experiment, Zn speciation in soil after harvesting showed that almost all Zn was found in the residual fraction followed by metal in the water-soluble plus exchangeable fraction and metal bound to organic matter. The most effective fertilizers maintaining Zn in the most labile fractions were Zn-phenolate, Zn-EDTA, and Zn-lignosulfonate. Conversely, in the incubation experiment, only a small percentage of Zn was found in the water-soluble plus exchangeable fraction and no differences in the Zn distribution were observed between the different fertilizer treatments. The micronutrient content in maize was positively correlated with the water-soluble plus exchangeable Zn as well as with the available Zn determined by the diethylenetriaminepentaacetic acid and Mehlich-3 methods, in the greenhouse experiment. Results of this study showed that the incubation experiment in acidic soil is not a suitable tool to establish the different effectiveness of Zn chelates in plants.

Molecular and phenotypic characterization of transgenic soybean expressing the Arabidopsis ferric chelate reductase gene, FRO2.

PubMed

Vasconcelos, Marta; Eckert, Helene; Arahana, Venancio; Graef, George; Grusak, Michael A; Clemente, Tom

2006-10-01

Soybean (Glycine max Merr.) production is reduced under iron-limiting calcareous soils throughout the upper Midwest regions of the US. Like other dicotyledonous plants, soybean responds to iron-limiting environments by induction of an active proton pump, a ferric iron reductase and an iron transporter. Here we demonstrate that heterologous expression of the Arabidopsis thaliana ferric chelate reductase gene, FRO2, in transgenic soybean significantly enhances Fe(+3) reduction in roots and leaves. Root ferric reductase activity was up to tenfold higher in transgenic plants and was not subjected to post-transcriptional regulation. In leaves, reductase activity was threefold higher in the transgenic plants when compared to control. The enhanced ferric reductase activity led to reduced chlorosis, increased chlorophyll concentration and a lessening in biomass loss in the transgenic events between Fe treatments as compared to control plants grown under hydroponics that mimicked Fe-sufficient and Fe-deficient soil environments. However, the data indicate that constitutive FRO2 expression under non-iron stress conditions may lead to a decrease in plant productivity as reflected by reduced biomass accumulation in the transgenic events under non-iron stress conditions. When grown at Fe(III)-EDDHA levels greater than 10 microM, iron concentration in the shoots of transgenic plants was significantly higher than control. The same observation was found in the roots in plants grown at iron levels higher than 32 microM Fe(III)-EDDHA. These results suggest that heterologous expression of an iron chelate reductase in soybean can provide a route to alleviate iron deficiency chlorosis.

[Susceptibility of enterococci to natural and synthetic iron chelators].

PubMed

Lisiecki, Paweł; Mikucki, Jerzy

2002-01-01

A total of 79 strains of enterococci belonging to 10 species were tested for susceptibility to natural and synthetic iron chelators. All strains produced siderophores. These enterococci were susceptible to three synthetic iron chelators only: 8-hydroxyquinoline, disodium versenate (EDTA) and o-phenanthroline. They were resistant to all other synthetic chelators: ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA), nitrilotriacetate, 2,2'-bipiridyl, salicylic acid, 8-hydroxy-5-sulphonic acid and to all natural chelators: ovotransferrine, human apotransferrine, horse apoferritine, desferrioxamine B, ferrichrome and rhodotorulic acid. The relations between susceptibility/resistance, iron assimilation and structure and stability constants of iron chelators were discussed.

Effects of zinc complexes on the distribution of zinc in calcareous soil and zinc uptake by maize.

PubMed

Alvarez, José M; Rico, María I

2003-09-10

The movement and availability of Zn from six organic Zn sources in a Typic Xerorthent (calcareous) soil were compared by incubation, column assay, and in a greenhouse study with maize (Zea mays L.). Zinc soil behavior was studied by sequential, diethylenetriaminepentaacetate, and Mehlich-3 extractions. In the incubation experiment, the differences in Zn concentration observed in the water soluble plus exchangeable fraction strongly correlated with Zn uptake by plants in the greenhouse experiment. Zinc applied to the surface of soil columns scarcely moved into deeper layers except for Zn-ethylenediaminetetraacetate (EDTA) that showed the greatest distribution of labile Zn throughout the soil and the highest proportion of leaching of the applied Zn. In the upper part of the column, changes in the chemical forms of all treatments occurred and an increase in organically complexed and amorphous Fe oxide-bound fractions was detected. However, the water soluble plus exchangeable fraction was not detected. The same results were obtained at the end of the greenhouse experiment. Significant increases were found in plant dry matter yield and Zn concentration as compared with the control treatment without Zn addition. Increasing Zn rate in the soil increased dry matter yield in all cases but Zn concentration in the plant increased only with Zn-EDTA and Zn-ethylenediaminedi-o-hydroxyphenyl-acetate (EDDHA) fertilizers. Higher Zn concentration in plants (50.9 mg kg(-)(1)) occurred when 20 mg Zn kg(-)(1) was added to the soil as Zn-EDTA. The relative effectiveness of the different Zn carriers in increasing Zn uptake was in the order: Zn-EDTA > Zn-EDDHA > Zn-heptagluconate >/= Zn-phenolate approximately Zn-polyflavonoid approximately Zn-lignosulfonate.

A proteome analysis of the response of a Pseudomonas aeruginosa oxyR mutant to iron limitation.

PubMed

Vinckx, Tiffany; Wei, Qing; Matthijs, Sandra; Noben, Jean-Paul; Daniels, Ruth; Cornelis, Pierre

2011-06-01

In Pseudomonas aeruginosa the response to oxidative stress is orchestrated by the LysR regulator OxyR by activation of the transcription of two catalase genes (katA and katB), of the alkyl-hydroxyperoxidases ahpCF and ahpB. Next to the expected high sensitivity to oxidative stress generated by reactive oxygen species (ROS: H(2)O(2), O(2)(-)), the oxyR mutant shows a defective growth under conditions of iron limitation (Vinckx et al. 2008). Although production and uptake of the siderophore pyoverdine is not affected by the absence of oxyR, the mutant is unable to satisfy its need for iron when grown under iron limiting conditions. In order to get a better insight into the effects caused by iron limitation on the physiological response of the oxyR mutant we decided to compare the proteomes of the wild type and the mutant grown in the iron-poor casamino acids medium (CAA), in CAA plus H(2)O(2), and in CAA plus the strong iron chelator ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid) (EDDHA). Especially in the presence of hydrogen peroxide the oxyR cells increase the production of stress proteins (Dps and IbpA). The superoxide dismutase SodM is produced in higher amounts in the oxyR mutant grown in CAA plus H(2)O(2). The PchB protein, a isochorismate-pyruvate lyase involved in the siderophore pyochelin biosynthesis is not detectable in the extracts from the oxyR mutant grown in the presence of hydrogen peroxide. When cells were grown in the presence of EDDHA, we observed a reduction of the ferric uptake regulator (Fur), and an increase in the two subunits of the succinyl-CoA synthetase and the fumarase FumC1.

Iron control of the Vibrio fischeri luminescence system in Escherichia coli.

PubMed

Dunlap, P V

1992-01-01

Iron influences luminescence in Vibrio fischeri; cultures iron-restricted for growth rate induce luminescence at a lower optical density (OD) than faster growing, iron-replete cultures. An iron restriction effect analogous to that in V. fischeri (slower growth, induction of luminescence at a lower OD) was established using Escherichia coli tonB and tonB+ strains transformed with recombinant plasmids containing the V. fischeri lux genes (luxR luxICDABEG) and grown in the presence and absence of the iron chelator ethylenediamine-di(o-hydroxylphenyl acetic acid) (EDDHA). This permitted the mechanism of iron control of luminescence to be examined. A fur mutant and its parent strain containing the intact lux genes exhibited no difference in the OD at induction of luminescence. Therefore, an iron-binding repressor protein apparently is not involved in iron control of luminescence. Furthermore, in the tonB and in tonB+ strains containing lux plasmids with Mu dI(lacZ) fusions in luxR, levels of beta-galactosidase activity (expression from the luxR promoter) and luciferase activity (expression from the luxICDABEG promoter) both increased by a similar amount (8-9 fold each for tonB, 2-3 fold each for tonB+) in the presence of EDDHA. Similar results were obtained with the luxR gene present on a complementing plasmid. The previously identified regulatory factors that control the lux system (autoinducer-LuxR protein, cyclic AMP-cAMP receptor protein) differentially control expression from the luxR and luxICDABEG promoters, increasing expression from one while decreasing expression from the other. Consequently, these results suggest that the effect of iron on the V. fischeri luminescence system is indirect.

Mutations in sit B and sit D genes affect manganese-growth requirements in Sinorhizobium meliloti.

PubMed

Platero, Raúl A; Jaureguy, Melina; Battistoni, Federico J; Fabiano, Elena R

2003-01-21

Two transposon-induced mutants of Sinorhizobium meliloti 242 were isolated based on their inability to grow on rich medium supplemented with the metal chelator ethylenediamine di-o-hydroxyphenylacetic acid (EDDHA) and either heme-compounds or siderophores as iron sources. Tagged loci of these mutants were identified as sit B and sit D genes. These genes encode components of an ABC (ATP-binding cassette) metal-type permease in several Gram-negative bacteria. In this work, the phenotypes of these two mutants were compared with those of two siderophore-mediated iron transport mutants. The results strongly implicate a role of the sit genes in manganese acquisition when this metal is limiting in S. meliloti.

Quantitative evaluation of inhibitory effect of various substances on anaerobic ammonia oxidation (anammox).

PubMed

Nakamura, Tomotaka; Harigaya, Yuhki; Kimura, Yuya; Kuroiwa, Megumi; Kurata, Yuhri; Isaka, Kazuichi; Suwa, Yuichi

2017-09-01

The inhibitory effect of 20 substances of various chemical species on the anaerobic ammonia oxidation (anammox) activity of an enrichment culture, predominated by Candidatus Brocadia, was determined systematically by using a 15 N tracer technique. The initial anammox rate was determined during first 25 min with a small-scale anaerobic batch incubation supplemented with possible inhibitors. Although Cu 2+ and Mn 2+ did not inhibit anammox, the remaining 18 substances [Ni 2+ , Zn 2+ , Co 2+ , [Formula: see text] , Fe 2+ , 4 amines, ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N'-bis (2-hydroxyphenylacetic acid) (EDDHA), citric acid, nitrilotriacetic acid (NTA), N,N-dimethylacetamide (DMA), 1,4-dioxane, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF) and tetrahydrofuran (THF)] were inhibitory. Inhibitory effect of NTA, EDDHA, THF, DMF, DMA and amines on anammox was first determined in this study. Inhibitory effects of metals were re-evaluated because chelators, which may interfere inhibitory effect, have been used to dissolve metal salts into assay solution. The relative anammox activities as a function of concentration of each substance were described successfully (R 2  > 0.91) either with a linear inhibition model or with a Michaelis-Menten-based inhibition model. IC 50 values were estimated based on either model, and were compared. The IC 50 values of the 4 chelators (0.06-2.7 mM) and 5 metal ions (0.02-1.09 mM) were significantly lower than those of the 4 amines (10.6-29.1 mM) and 5 organic solvents (3.5-82 mM). Although it did not show any inhibition within 25 min, 0.1 mM Cu 2+ completely inhibited anammox activity in 240 min, suggesting that the inhibitory effect caused by Cu 2+ is time-dependent. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Identification of type II and type III pyoverdine receptors from Pseudomonas aeruginosa.

PubMed

de Chial, Magaly; Ghysels, Bart; Beatson, Scott A; Geoffroy, Valérie; Meyer, Jean Marie; Pattery, Theresa; Baysse, Christine; Chablain, Patrice; Parsons, Yasmin N; Winstanley, Craig; Cordwell, Stuart J; Cornelis, Pierre

2003-04-01

Pseudomonas aeruginosa produces, under conditions of iron limitation, a high-affinity siderophore, pyoverdine (PVD), which is recognized at the level of the outer membrane by a specific TonB-dependent receptor, FpvA. So far, for P. aeruginosa, three different PVDs, differing in their peptide chain, have been described (types I-III), but only the FpvA receptor for type I is known. Two PVD-producing P. aeruginosa strains, one type II and one type III, were mutagenized by a mini-TnphoA3 transposon. In each case, one mutant unable to grow in the presence of the strong iron chelator ethylenediaminedihydroxyphenylacetic acid (EDDHA) and the cognate PVD was selected. The first mutant, which had an insertion in the pvdE gene, upstream of fpvA, was unable to take up type II PVD and showed resistance to pyocin S3, which is known to use type II FpvA as receptor. The second mutant was unable to take up type III PVD and had the transposon insertion in fpvA. Cosmid libraries of the respective type II and type III PVD wild-type strains were constructed and screened for clones restoring the capacity to grow in the presence of PVD. From the respective complementing genomic fragments, type II and type III fpvA sequences were determined. When in trans, type II and type III fpvA restored PVD production, uptake, growth in the presence of EDDHA and, in the case of type II fpvA, pyocin S3 sensitivity. Complementation of fpvA mutants obtained by allelic exchange was achieved by the presence of cognate fpvA in trans. All three receptors posses an N-terminal extension of about 70 amino acids, similar to FecA of Escherichia coli, but only FpvAI has a TAT export sequence at its N-terminal end.

Selection of olive varieties for tolerance to iron chlorosis.

PubMed

Alcántara, Esteban; Cordeiro, Antonio Manuel; Barranco, Diego

2003-12-01

Under certain conditions, olive trees grown on calcareous soils suffer from iron chlorosis. In the present study several olive varieties and scion-rootstock combinations were evaluated for their tolerance to iron chlorosis. Plants were grown over several months in pots with a calcareous soil, under two fertilization treatments. These consisted of periodic applications of nutrient solutions containing either, 30 micromol/L FeEDDHA or not Fe. Tolerance was assessed by the chlorosis and growth parameters of plants grown without Fe, compared to those plants grown with Fe. Results show that there are differences in tolerance among olive varieties and that tolerance is mainly determined by the genotype of the rootstock. These results open the way to use tolerant varieties for those conditions where iron chlorosis could become a problem.

Nanosiderite is effective to alleviate iron chlorosis in sensitive plants growing on calcareous soils

NASA Astrophysics Data System (ADS)

Sánchez-Alcalá, I.; del Campillo, M. C.; Barrón, V.; Torrent, J.

2012-04-01

Key words: siderite, iron chlorosis, calcareous soil, goethite, lepidocrocite Nanosized siderite (FeCO3) prepared by mixing FeSO4 and K2CO3 solutions [either alone or in presence of phosphate (siderites SID and SIDP, respectively)] was used in our experiments. The products of oxidation of siderite in a calcite suspension were goethite or a mixture of goethite and lepidocrocite when phosphate was present. These iron oxides were nanosized and acid NH4oxalate-soluble, which suggested they could be a good source of iron (Fe) for plants sensitive to Fe deficiency yellowing (chlorosis). To evaluate the effectiveness and long-term effects of suspensions of siderite mixed with calcareous soil to prevent Fe chlorosis, a pot growth experiment was carried out with five consecutive crops: chickpea (twice), peanut (twice) and strawberry. Suspensions of siderites (SID and SIDP) were mixed with 220 g of soil at the beginning of the experiment at rates of 0.24, 0.46, 0.93 and 1.40 g siderite (0.12, 0.22, 0.45, and 0.67 g Fe) kg-1 soil. A control (no Fe added) and a positive control (Fe-chelate as FeEDDHA before each cropping) were included. The concentration of chlorophyll in the youngest leaves was estimated three times for chickpea and peanut, and five times for strawberry via the SPAD value (SPAD 502 portable chlorophyll meter). The SPAD for the control plants was lower than that for Fe-fertilized plants. For all crops, times and siderite types, SPAD tended to systematically increase with increasing siderite dose, and SID and SIDP had similar effectiveness. At harvest, the SPAD for the plants fertilized with the highest siderite dose (1.40 g kg-1) did not differ significantly from that for FeEDDHA-fertilized plants. Our results suggest in summary that siderite is effective in preventing iron chlorosis and has a long-lasting effect, as the likely result of the high specific surface and high solubility of the crystalline Fe oxides resulting from its oxidation. Futhermore, siderite is readily prepared in the field, not easily leached from the soil and environmentally safe, thus constituting a good Fe fertilizer. Acknowledgments: This work was funded by the Spain's Ministerio de Ciencia e Innovación and the European Regional Development Fund (Projects AGL 2005-06691-C02-01 and AGL 2008-05053-C02-02).

Demetalation of Fe, Mn, and Cu chelates and complexes: application to the NMR analysis of micronutrient fertilizers.

PubMed

López-Rayo, Sandra; Lucena, Juan J; Laghi, Luca; Cremonini, Mauro A

2011-12-28

The application of nuclear magnetic resonance (NMR) for the quality control of fertilizers based on Fe(3+), Mn(2+), and Cu(2+) chelates and complexes is precluded by the strong paramagnetism of metals. Recently, a method based on the use of ferrocyanide has been described to remove iron from commercial iron chelates based on the o,o-EDDHA [ethylenediamine-N,N'bis(2-hydroxyphenylacetic)acid] chelating agent for their analysis and quantification by NMR. The present work extended that procedure to other paramagnetic ions, manganese and copper, and other chelating, EDTA (ethylenediaminetetraacetic acid), IDHA [N-(1,2-dicarboxyethyl)-d,l-aspartic acid], and complexing agents, gluconate and heptagluconate. Results showed that the removal of the paramagnetic ions was complete, allowing us to obtain (1)H NMR spectra characterized by narrow peaks. The quantification of the ligands by NMR and high-performance liquid chromatography showed that their complete recovery was granted. The NMR analysis enabled detection and quantification of unknown impurities without the need of pure compounds as internal standards.

Nature of impurities in fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+) chelates.

PubMed

Alvarez-Fernández, Ana; Cremonini, Mauro A; Sierra, Miguel A; Placucci, Giuseppe; Lucena, Juan J

2002-01-16

Iron chelates derived from ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA), ethylenediaminedi(o-hydroxy-p-methylphenylacetic) acid (EDDHMA), ethylenediaminedi(2-hydroxy-5-sulfophenylacetic) acid (EDDHSA), and ethylenediaminedi(5-carboxy-2-hydroxyphenylacetic) acid (EDDCHA) are remarkably efficient in correcting iron chlorosis in plants growing in alkaline soils. This work reports the determination of impurities in commercial samples of fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+). The active components (EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+)) were separated easily from other compounds present in the fertilizers by HPLC. Comparison of the retention times and the UV-visible spectra of the peaks obtained from commercial EDDHSA/Fe(3+) and EDDCHA/Fe(3+) samples with those of standard solutions showed that unreacted starting materials (p-hydroxybenzenesulfonic acid and p-hydroxybenzoic acid, respectively) were always present in the commercial products. 1D and 2D NMR experiments showed that commercial fertilizers based on EDDHMA/Fe(3+) contained impurities having structures tentatively assigned to iron chelates of two isomers of EDDHMA. These findings suggest that current production processes of iron chelates used in agriculture need to be improved.

Immobilization of Fe chelators on sepharose gel and its effect on their chemical properties.

PubMed

Yehuda, Zehava; Hadar, Yitzhak; Chen, Yona

2003-09-24

Iron chelates are usually costly and easily leached beyond the root zone. This creates a need to frequently replenish the rhizosphere with chelated Fe and might contaminate groundwater with organic compounds and metals. The development of a slow-release Fe fertilizer that will efficiently supply Fe to plants while exhibiting high resistance toward leaching and/or degradation in the rhizosphere has been the focus of this study. Desferrioxamine B (DFOB) and ethylenediaminebis(o-hydroxyphenylacetic acid) (EDDHA) were immobilized on Sepharose. (13)C NMR and FTIR measurements confirmed that coupling of DFOB to the gel did not appear to influence its ability to chelate Fe(3+) or its binding nature. Isotherms for the immobilized ligands were determined in the presence of 1 mM HEDTA, at 25 degrees C and at an ionic strength of 0.1 M. The isotherms showed a high affinity of Fe(3+) to the ligands and binding up to saturation level throughout the pH range examined (4.0-9.0). The K(app) values for the immobilized Fe chelates were determined using a modified Scatchard model and found to be lower than the soluble ones. This decrease in K(app) might facilitate Fe uptake from these chelates by plants.

Isoelectric focusing of small non-covalent metal species from plants.

PubMed

Köster, Jessica; Hayen, Heiko; von Wirén, Nicolaus; Weber, Günther

2011-03-01

IEF is known as a powerful electrophoretic separation technique for amphoteric molecules, in particular for proteins. The objective of the present work is to prove the suitability of IEF also for the separation of small, non-covalent metal species. Investigations are performed with copper-glutathione complexes, with the synthetic ligand ethylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid (EDDHA) and respective metal complexes (Fe, Ga, Al, Ni, Zn), and with the phytosiderophore 2'-deoxymugineic acid (DMA) and its ferric complex. It is shown that ethylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid and DMA species are stable during preparative scale IEF, whereas copper-glutathione dissociates considerably. It is also shown that preparative scale IEF can be applied successfully to isolate ferric DMA from real plant samples, and that multidimensional separations are possible by combining preparative scale IEF with subsequent HPLC-MS analysis. Focusing of free ligands and respective metal complexes with di- and trivalent metals results in different pIs, but CIEF is usually needed for a reliable estimation of pI values. Limitations of the proposed methods (preparative IEF and CIEF) and consequences of the results with respect to metal speciation in plants are discussed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Involvement of the TonB System in Tolerance to Solvents and Drugs in Pseudomonas putida DOT-T1E

PubMed Central

Godoy, Patricia; Ramos-González, María Isabel; Ramos, Juan L.

2001-01-01

Pseudomonas putida DOT-T1E is able to grow with glucose as the carbon source in liquid medium with 1% (vol/vol) toluene or 17 g of (123 mM) p-hydroxybenzoate (4HBA) per liter. After random mini-Tn5′phoA-Km mutagenesis, we isolated the mutant DOT-T1E-PhoA5, which was more sensitive than the wild type to 4HBA (growth was prevented at 6 g/liter) and toluene (the mutant did not withstand sudden toluene shock). Susceptibility to toluene and 4HBA resulted from the reduced efflux of these compounds from the cell, as revealed by accumulation assays with 14C-labeled substrates. The mutant was also more susceptible to a number of antibiotics, and its growth in iron-deficient minimal medium was inhibited in the presence of ethylenediamine-di(o-hydroxyphenylacetic acid (EDDHA). Cloning the mutation in the PhoA5 strain and sequencing the region adjacent showed that the mini-Tn5 transposor interrupted the exbD gene, which forms part of the exbBD tonB operon. Complementation by the exbBD and tonB genes cloned in pJB3-Tc restored the wild-type characteristics to the PhoA5 strain. PMID:11514511

Involvement of the TonB system in tolerance to solvents and drugs in Pseudomonas putida DOT-T1E.

PubMed

Godoy, P; Ramos-González, M I; Ramos, J L

2001-09-01

Pseudomonas putida DOT-T1E is able to grow with glucose as the carbon source in liquid medium with 1% (vol/vol) toluene or 17 g of (123 mM) p-hydroxybenzoate (4HBA) per liter. After random mini-Tn5'phoA-Km mutagenesis, we isolated the mutant DOT-T1E-PhoA5, which was more sensitive than the wild type to 4HBA (growth was prevented at 6 g/liter) and toluene (the mutant did not withstand sudden toluene shock). Susceptibility to toluene and 4HBA resulted from the reduced efflux of these compounds from the cell, as revealed by accumulation assays with (14)C-labeled substrates. The mutant was also more susceptible to a number of antibiotics, and its growth in iron-deficient minimal medium was inhibited in the presence of ethylenediamine-di(o-hydroxyphenylacetic acid (EDDHA). Cloning the mutation in the PhoA5 strain and sequencing the region adjacent showed that the mini-Tn5 transposor interrupted the exbD gene, which forms part of the exbBD tonB operon. Complementation by the exbBD and tonB genes cloned in pJB3-Tc restored the wild-type characteristics to the PhoA5 strain.

Toxicity and deficiency of copper in Elsholtzia splendens affect photosynthesis biophysics, pigments and metal accumulation.

PubMed

Peng, Hongyun; Kroneck, Peter M H; Küpper, Hendrik

2013-06-18

Elsholtzia splendens is a copper-tolerant plant species growing on copper deposits in China. Spatially and spectrally resolved kinetics of in vivo absorbance and chlorophyll fluorescence in mesophyll of E. splendens were used to investigate the copper-induced stress from deficiency and toxicity as well as the acclimation to excess copper stress. The plants were cultivated in nutrient solutions containing either Fe(III)-EDTA or Fe(III)-EDDHA. Copper toxicity affected light-acclimated electron flow much stronger than nonphotochemical quenching (NPQ) or dark-acclimated photochemical efficiency of PSIIRC (Fv/Fm). It also changed spectrally resolved Chl fluorescence kinetics, in particular by strengthening the short-wavelength (<700 nm) part of NPQ altering light harvesting complex II (LHCII) aggregation. Copper toxicity reduced iron accumulation, decreased Chls and carotenoids in leaves. During acclimation to copper toxicity, leaf copper decreased but leaf iron increased, with photosynthetic activity and pigments recovering to normal levels. Copper tolerance in E. splendens was inducible; acclimation seems be related to homeostasis of copper and iron in E. splendens. Copper deficiency appeared at 10 mg copper per kg leaf DW, leading to reduced growth and decreased photosynthetic parameters (F0, Fv/Fm, ΦPSII). The importance of these results for evaluating responses of phytoremediation plants to stress in their environment is discussed.

Micropropagation of peach rootstocks and cultivars.

PubMed

Balla, Ildikó; Mansvelt, Lucienne

2013-01-01

Peach (Prunus persica (L.) Batsch) is one of the most popular stone fruits, commercially produced largely in Mediterranean and, to a lesser extent, in continental climatic conditions. Several breeding programs with different aims release annually large numbers of new cultivars. Micropropagation offers a suitable method to provide the growers of sufficient quantities of rootstocks, as well as of pathogen-free planting material of old and new cultivars.An effective four-step micropropagation procedure for cultivar and rootstock production is described here, based on the use of modified MS and WPM media. The health status of the initial shoot tips is very important, also because the growth and proliferation rate of shoot cultures from virus-infected clones are generally very poor. Proliferation and elongation phases depend on the major macro-elements, as well as the content and ratio of plant growth regulators. It is important to grow the cultures at 22°C, as hyperhydricity may develop at higher temperatures. Although sucrose is the most common carbon source used during proliferation and rooting, for some peach cultivars and rootstocks the replacement of sucrose (10 g/L) with glucose (20 g/L) in the rooting medium improves the rooting and survival rates of plants in the acclimatization phase. The rooting rate of the rootstock "Cadaman" is improved with the chelated form of iron FeEDDHA at 150 mg/L. Rooted plants are acclimatized in greenhouse under high humidity conditions.

Iron Requirement and Iron Uptake from Various Iron Compounds by Different Plant Species

PubMed Central

Christ, Rudolf A.

1974-01-01

The Fe requirements of four monocotyledonous plant species (Avena sativa L., Triticum aestivum L., Oryza sativa L., Zea mays L.) and of three dicotyledonous species (Lycopersicum esculentum Mill., Cucumis sativus L., Glycine maxima (L.) Merr.) in hydroponic cultures were ascertained. Fe was given as NaFe-EDDHA chelate (Fe ethylenediamine di (O-hydroxyphenylacetate). I found that the monocotyledonous species required a substantially higher Fe concentration in the nutrient solution in order to attain optimum growth than did the dicotyledonous species. Analyses showed that the process of iron uptake was less efficient with the monocotyledonous species. When the results obtained by using chelated Fe were compared with those using ionic Fe, it was shown that the inefficient species were equally inefficient in utilizing Fe3+ ions. However, the differences between the efficient and the inefficient species disappeared when Fe2+ was used. This confirms the work of others who postulated that Fe3+ is reduced before uptake of chelated iron by the root. In addition, it was shown that reduction also takes place when Fe is used in ionic form. The efficiency of Fe uptake seems to depend on the efficiency of the root system of the particular plant species in reducing Fe3+. The removal of Fe from the chelate complex after reduction to Fe2+ seems to present no difficulties to the various plant species. PMID:16658933

Iron Supply Affects Anthocyanin Content and Related Gene Expression in Berries of Vitis vinifera cv. Cabernet Sauvignon.

PubMed

Shi, Pengbao; Li, Bing; Chen, Haiju; Song, Changzheng; Meng, Jiangfei; Xi, Zhumei; Zhang, Zhenwen

2017-02-14

Anthocyanins are important compounds for red grape and red wine quality, and can be influenced by supply of nutrients such as nitrogen, phosphorus, potassium, zinc, and iron. The present work aims to gain a better understanding of the effect of iron supply on anthocyanins concentration in grape berries. To this end, own-rooted four-year-old Cabernet Sauvignon grapevines ( Vitis vinifera ) were fertigated every three days with 0, 23, 46, 92, and 184 μM iron (Fe) from ferric ethylenediamine di ( o -hydroxyphenylacetic) acid (Fe-EDDHA) in a complete nutrient solution. Fe deficiency or excess generally led to higher concentrations of titratable acidity and skin/berry ratio, and to lower reducing sugar content, sugar/acid ratio, pH, berry weight, and concentration of anthocyanins. Most of the individual anthocyanins detected in this study, except cyanidin-3- O -glucoside, delphinidin-3- O -glucoside, and cyanidin-3- O -(6- O -coumaryl)-glucoside, in moderate Fe treatment (46 μM) grapes were significantly higher than those of other treatments. Genes encoding chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), leucoanthocyanidin dioxygenase (LDOX), and anthocyanin O -methyltransferase (AOMT) exhibited higher transcript levels in berries from plants cultivated with 46 μM Fe compared to the ones cultivated with other Fe concentrations. We suggest that grape sugar content, anthocyanins content, and transcriptions of genes involved in anthocyanin biosynthesis were correlated with Fe supply concentrations.

The memory of iron stress in strawberry plants.

PubMed

Gama, Florinda; Saavedra, Teresa; da Silva, José Paulo; Miguel, Maria Graça; de Varennes, Amarilis; Correia, Pedro José; Pestana, Maribela

2016-07-01

To provide information towards optimization of strategies to treat Fe deficiency, experiments were conducted to study the responses of Fe-deficient plants to the resupply of Fe. Strawberry (Fragaria × ananassa Duch.) was used as model plant. Bare-root transplants of strawberry (cv. 'Diamante') were grown for 42 days in Hoagland's nutrient solutions without Fe (Fe0) and containing 10 μM of Fe as Fe-EDDHA (control, Fe10). For plants under Fe0 the total chlorophyll concentration of young leaves decreased progressively on time, showing the typical symptoms of iron chlorosis. After 35 days the Fe concentration was 6% of that observed for plants growing under Fe10. Half of plants growing under Fe0 were then Fe-resupplied by adding 10 μM of Fe to the Fe0 nutrient solution (FeR). Full Chlorophyll recovery of young leaves took place within 12 days. Root ferric chelate-reductase activity (FCR) and succinic and citric acid concentrations increased in FeR plants. Fe partition revealed that FeR plants expressively accumulated this nutrient in the crown and flowers. This observation can be due to a passive deactivation mechanism of the FCR activity, associated with continuous synthesis of succinic and citric acids at root level, and consequent greater uptake of Fe. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Modulation of the antioxidative response of Spartina densiflora against iron exposure.

PubMed

Martínez Domínguez, David; Torronteras Santiago, Rafael; Córdoba García, Francisco

2009-06-01

Spartina densiflora, an invader cordgrass living in polluted salt marshes of the Odiel estuary (SW Spain), was collected and cultured under controlled laboratory conditions. After acclimation to non-polluted soils for 28 days, both metabolites and enzymes activities used as indicators of oxidative stress were reduced significantly. Then, plants were exposed to 500 and 1000 ppm Fe-ethylenediamine-N,N'-2-hydroxyphenyl acetic acid (EDDHA) for 28 days. Our data demonstrate that iron content in leaves was enhanced by iron exposure. This iron increase caused an enhancement in the concentration of H2O2, hydroperoxides and lipid peroxidation, and a decrease in chlorophyll levels. Thus, iron exposure led to oxidative stress conditions. However, oxidative indicators stabilised after first 2 weeks of exposure, although the highest iron levels in leaves were reached at the end of treatments. Iron exposure induced an enhancement of catalase, ascorbate peroxidase and guaiacol peroxidase activities, together with an increase in total and oxidised ascorbate. This response may be defensive against oxidative stress and thus help to explain why cell oxidative damages were stabilised. Thus, by using a sensitive long-time protocol, iron-dependent oxidative damages may be controlled and even reverted successfully by the activation of the antioxidative defences of S. densiflora. This efficient antioxidative system, rapidly modulated in response to excess iron and other environmental stressors, may account for S. densiflora's successful adaptation to stress conditions in its habitat.

Stability, frequency and multiplicity of transposon insertions in the pyoverdine region in the chromosomes of different fluorescent pseudomonads.

PubMed

Cornelis, P; Anjaiah, V; Koedam, N; Delfosse, P; Jacques, P; Thonart, P; Neirinckx, L

1992-07-01

Tn5 mutagenesis of different fluorescent pseudomonads was achieved by conjugational transfer of the suicide vector pSUP 10141. Pyoverdine negative (Pvd-) mutants were detected by the absence of fluorescence on King's B medium and by their inability to grow in the presence of the iron chelator EDDHA [ethylenediamine di(o-hydroxyphenylacetic acid)]. In P. fluorescens ATCC 17400 and three rhizosphere isolates (one P. putida and two P. fluorescens), the percentage of Pvd- mutants ranged between 0 and 0.54%. In a P. chlororaphis rhizosphere isolate, this percentage was higher (4%). In these mutants both of the Tn5 antibiotic resistances (Km and Tc) were stable and the transposon could be detected by hybridization. In Pvd- mutants of P. fluorescens ATCC 17400, the transposon was found to be inserted twice in the chromosome while single insertions were detected in the DNA of other, randomly tested mutants. In P. aeruginosa PAO1, where 13.1% of the mutants were Pvd-, both antibiotic resistances were rapidly lost and accordingly no transposon insertion could be detected by hybridization. However, the Pvd- phenotype was generally stable in these mutants. The plasmid pNK862 containing a mini-Tn10 transposon was introduced by electroporation into P. aeruginosa PAO1 and Kmr mutants were recovered, 89% of which were Pvd- and confirmed to be P. aeruginosa by PCR amplification of the P. aeruginosa lipoprotein gene. The mini-Tn10 insertions were also found to be unstable in PAO1.

Reactivity and effectiveness of traditional and novel ligands for multi-micronutrient fertilization in a calcareous soil

PubMed Central

López-Rayo, Sandra; Nadal, Paloma; Lucena, Juan J.

2015-01-01

This study compares the effectiveness of multi-micronutrient formulations containing iron (Fe), manganese (Mn), and zinc (Zn) with traditional (EDTA, DTPA, HEEDTA, and EDDHAm) or novel chelates (o,p-EDDHA, S,S-EDDS, and IDHA) and natural complexing agents (gluconate and lignosulfonate). The stability and reactivity of the formulations were studied on batch experiments with calcareous soil and by speciation modeling. Formulations containing traditional ligands maintained higher Mn but lower Zn concentration in soil solution than the novel ligands. The gluconate and lignosulfonate maintained low concentrations of both Mn and Zn in soil solution. Selected formulations were applied into calcareous soil and their efficacy was evaluated in a pot experiment with soybean. The formulation containing DTPA led to the highest Zn concentration in plants, as well as the formulation containing S,S-EDDS in the short-term, which correlated with its biodegradability. The application of traditional or novel ligands in formulations did not result in sufficient plant Mn concentrations, which was related to the low Mn stability observed for all formulations under moderate oxidation conditions. The results highlight the need to consider the effect of metals and ligands interactions in multi-nutrient fertilization and the potential of S,S-EDDS to be used for Zn fertilization. Furthermore, it is necessary to explore new sources of Mn fertilization for calcareous soils that have greater stability and efficiency, or instead to use foliar fertilization. PMID:26442065

Carbonic anhydrase inhibitors. A general approach for the preparation of water-soluble sulfonamides incorporating polyamino-polycarboxylate tails and of their metal complexes possessing long-lasting, topical intraocular pressure-lowering properties.

PubMed

Scozzafava, Andrea; Menabuoni, Luca; Mincione, Francesco; Supuran, Claudiu T

2002-03-28

Reaction of polyamino-polycarboxylic acids or their dianhydrides with aromatic/heterocyclic sulfonamides possessing a free amino/imino/hydrazino/hydroxy group afforded mono- and bis-sulfonamides containing polyamino-polycarboxylic acid moieties in their molecule. The acids/anhydrides used in synthesis included IDA, NTA, EDDA, EDTA and EDTA dianhydride, DTPA and DTPA dianhydride, EGTA and EGTA dianhydride, and EDDHA, among others. All the newly prepared derivatives showed strong affinity toward isozymes I, II, and IV of carbonic anhydrase (CA). Metal complexes of the new compounds have also been prepared. Metal ions used in such preparations included di- and trivalent main-group and transition cations, such as Zn(II), Cu(II), Al(III), etc. Some of the new sulfonamides/disulfonamides obtained in this way, as well as their metal complexes, behaved as nanomolar CA inhibitors against isozymes II and IV, being slightly less effective in inhibiting isozyme I. Some of these sulfonamides as well as their metal complexes strongly lowered intraocular pressure (IOP) when applied topically, directly into the normotensive/glaucomatous rabbit eye, as 1-2% water solutions/suspensions. The good water solubility of these sulfonamide CA inhibitors, correlated with the neutral pH of their water solutions used in the ophthalmologic applications and the long duration of action of the IOP-lowering effect, makes them interesting candidates for developing novel types of antiglaucoma drugs devoid of serious topical side effects.

Isotope pattern deconvolution as a tool to study iron metabolism in plants.

PubMed

Rodríguez-Castrillón, José Angel; Moldovan, Mariella; García Alonso, J Ignacio; Lucena, Juan José; García-Tomé, Maria Luisa; Hernández-Apaolaza, Lourdes

2008-01-01

Isotope pattern deconvolution is a mathematical technique for isolating distinct isotope signatures from mixtures of natural abundance and enriched tracers. In iron metabolism studies measurement of all four isotopes of the element by high-resolution multicollector or collision cell ICP-MS allows the determination of the tracer/tracee ratio with simultaneous internal mass bias correction and lower uncertainties. This technique was applied here for the first time to study iron uptake by cucumber plants using 57Fe-enriched iron chelates of the o,o and o,p isomers of ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA) and ethylenediamine tetraacetic acid (EDTA). Samples of root, stem, leaves, and xylem sap, after exposure of the cucumber plants to the mentioned 57Fe chelates, were collected, dried, and digested using nitric acid. The isotopic composition of iron in the samples was measured by ICP-MS using a high-resolution multicollector instrument. Mass bias correction was computed using both a natural abundance iron standard and by internal correction using isotope pattern deconvolution. It was observed that, for plants with low 57Fe enrichment, isotope pattern deconvolution provided lower tracer/tracee ratio uncertainties than the traditional method applying external mass bias correction. The total amount of the element in the plants was determined by isotope dilution analysis, using a collision cell quadrupole ICP-MS instrument, after addition of 57Fe or natural abundance Fe in a known amount which depended on the isotopic composition of the sample.

Reactivity and effectiveness of traditional and novel ligands for multi-micronutrient fertilization in a calcareous soil.

PubMed

López-Rayo, Sandra; Nadal, Paloma; Lucena, Juan J

2015-01-01

This study compares the effectiveness of multi-micronutrient formulations containing iron (Fe), manganese (Mn), and zinc (Zn) with traditional (EDTA, DTPA, HEEDTA, and EDDHAm) or novel chelates (o,p-EDDHA, S,S-EDDS, and IDHA) and natural complexing agents (gluconate and lignosulfonate). The stability and reactivity of the formulations were studied on batch experiments with calcareous soil and by speciation modeling. Formulations containing traditional ligands maintained higher Mn but lower Zn concentration in soil solution than the novel ligands. The gluconate and lignosulfonate maintained low concentrations of both Mn and Zn in soil solution. Selected formulations were applied into calcareous soil and their efficacy was evaluated in a pot experiment with soybean. The formulation containing DTPA led to the highest Zn concentration in plants, as well as the formulation containing S,S-EDDS in the short-term, which correlated with its biodegradability. The application of traditional or novel ligands in formulations did not result in sufficient plant Mn concentrations, which was related to the low Mn stability observed for all formulations under moderate oxidation conditions. The results highlight the need to consider the effect of metals and ligands interactions in multi-nutrient fertilization and the potential of S,S-EDDS to be used for Zn fertilization. Furthermore, it is necessary to explore new sources of Mn fertilization for calcareous soils that have greater stability and efficiency, or instead to use foliar fertilization.

Improved recovery of cryotherapy-treated shoot tips following thermotherapy of in vitro-grown stock shoots of raspberry (Rubus idaeus L.).

PubMed

Wang, Qiaochun; Valkonen, Jari P T

2009-01-01

Raspberry bushy dwarf virus (RBDV) can be efficiently eradicated from raspberry plants (Rubus idaeus) by a procedure combining thermotherapy and cryotherapy. However, the bottleneck of this procedure is that, following thermotherapy, cryopreserved shoot tips become chlorotic during regrowth and eventually die after several subcultures. In addition, survival of heat-treated stock shoots and recovery of cryopreserved shoot tips following thermotherapy are low. The present study focused towards improving regrowth of cryopreserved raspberry shoot tips following thermotherapy. Results showed that preconditioning stock shoots with salicylic acid (SA; 0.01-0.1 mM) markedly increased survival of stock shoots after 4 weeks of thermotherapy. Regrowth of cryopreserved shoot tips following thermotherapy was also significantly enhanced when SA (0.05-0.1 mM) was used for preconditioning stock shoots. Addition of either Fe-ethylenediaminetetracetic acid (Fe-EDTA, 50 mg per L) or Fe-ethylenediaminedi(o)hydroxyphenylacetic acid (Fe-EDDHA, 50 mg per L) to post-culture medium strongly promoted regrowth and totally prevented chlorosis of shoots regenerated from cryopreserved shoot tips following thermotherapy. Using the parameters optimized in the present study, about 80 percent survival of heat-treated stock shoots and about 33 percent regrowth of cryopreserved shoot tips following thermotherapy were obtained. Morphology of plants regenerated from cryopreserved shoot tips following thermotherapy was identical to that of control plants, based on observations of leaf shape and size, internode length and plant height. Optimization of the thermotherapy procedure followed by cryotherapy will facilitate the wider application of this technique to eliminate viruses which can invade meristems.

Iron Uptake Mechanisms in the Fish Pathogen Tenacibaculum maritimum

PubMed Central

Avendaño-Herrera, Ruben; Toranzo, Alicia E.; Romalde, Jesús L.; Lemos, Manuel L.; Magariños, Beatriz

2005-01-01

We present here the first evidence of the presence of iron uptake mechanisms in the bacterial fish pathogen Tenacibaculum maritimum. Representative strains of this species, with different serotypes and origins, were examined. All of them were able to grow in the presence of the chelating agent ethylenediamine-di- (o-hydroxyphenyl acetic acid) (EDDHA) and also produced siderophores. Cross-feeding assays suggest that the siderophores produced are closely related. In addition, all T. maritimum strains utilized transferrin, hemin, hemoglobin, and ferric ammonic citrate as iron sources when added to iron-deficient media. Whole cells of all T. maritimum strains, grown under iron-supplemented or iron-restricted conditions, were able to bind hemin, indicating the existence of constitutive binding components located at the T. maritimum cell surface. This was confirmed by the observation that isolated total and outer membrane proteins from all of the strains, regardless of the iron levels of the media, were able to bind hemin, with the outer membranes showing the strongest binding. proteinase K treatment of whole cells did not affect the hemin binding, indicating that, in addition to proteins, some protease-resistant components could also bind hemin. At least three outer membrane proteins were induced in iron-limiting conditions, and all strains, regardless of their serotype, showed a similar pattern of induced proteins. The results of the present study suggest that T. maritimum possesses at least two different systems of iron acquisition: one involving the synthesis of siderophores and another that allows the utilization of heme groups as iron sources by direct binding. PMID:16269729

Iron uptake mechanisms in the fish pathogen Tenacibaculum maritimum.

PubMed

Avendaño-Herrera, Ruben; Toranzo, Alicia E; Romalde, Jesús L; Lemos, Manuel L; Magariños, Beatriz

2005-11-01

We present here the first evidence of the presence of iron uptake mechanisms in the bacterial fish pathogen Tenacibaculum maritimum. Representative strains of this species, with different serotypes and origins, were examined. All of them were able to grow in the presence of the chelating agent ethylenediamine-di-(o-hydroxyphenyl acetic acid) (EDDHA) and also produced siderophores. Cross-feeding assays suggest that the siderophores produced are closely related. In addition, all T. maritimum strains utilized transferrin, hemin, hemoglobin, and ferric ammonic citrate as iron sources when added to iron-deficient media. Whole cells of all T. maritimum strains, grown under iron-supplemented or iron-restricted conditions, were able to bind hemin, indicating the existence of constitutive binding components located at the T. maritimum cell surface. This was confirmed by the observation that isolated total and outer membrane proteins from all of the strains, regardless of the iron levels of the media, were able to bind hemin, with the outer membranes showing the strongest binding. Proteinase K treatment of whole cells did not affect the hemin binding, indicating that, in addition to proteins, some protease-resistant components could also bind hemin. At least three outer membrane proteins were induced in iron-limiting conditions, and all strains, regardless of their serotype, showed a similar pattern of induced proteins. The results of the present study suggest that T. maritimum possesses at least two different systems of iron acquisition: one involving the synthesis of siderophores and another that allows the utilization of heme groups as iron sources by direct binding.

Role of the Fur Regulon in Iron Transport in Bacillus subtilis

PubMed Central

Ollinger, Juliane; Song, Kyung-Bok; Antelmann, Haike; Hecker, Michael; Helmann, John D.

2006-01-01

The Bacillus subtilis ferric uptake regulator (Fur) protein mediates the iron-dependent repression of at least 20 operons encoding ∼40 genes. We investigated the physiological roles of Fur-regulated genes by the construction of null mutations in 14 transcription units known or predicted to function in siderophore biosynthesis or iron uptake. We demonstrate that ywbLMN, encoding an elemental iron uptake system orthologous to the copper oxidase-dependent Fe(III) uptake system of Saccharomyces cerevisiae, is essential for growth in low iron minimal medium lacking citric acid. 2,3-Dihydroxybenzoyl-glycine (Itoic acid), the siderophore precursor produced by laboratory strains of B. subtilis, is of secondary importance. In the presence of citrate, the YfmCDEF ABC transporter is required for optimal growth. B. subtilis is unable to grow in minimal medium containing the iron chelator EDDHA unless the ability to synthesize the intact bacillibactin siderophore is restored (by the introduction of a functional sfp gene) or exogenous siderophores are provided. Utilization of the catecholate siderophores bacillibactin and enterobactin requires the FeuABC importer and the YusV ATPase. Utilization of hydroxamate siderophores requires the FhuBGC ABC transporter together with the FhuD (ferrichrome) or YxeB (ferrioxamine) substrate-binding proteins. Growth with schizokinen or arthrobactin is at least partially dependent on the YfhA YfiYZ importer and the YusV ATPase. We have also investigated the effects of a fur mutation on the proteome and documented the derepression of 11 Fur-regulated proteins, including a newly identified thioredoxin reductase homolog, YcgT. PMID:16672620

Role of the Fur regulon in iron transport in Bacillus subtilis.

PubMed

Ollinger, Juliane; Song, Kyung-Bok; Antelmann, Haike; Hecker, Michael; Helmann, John D

2006-05-01

The Bacillus subtilis ferric uptake regulator (Fur) protein mediates the iron-dependent repression of at least 20 operons encoding approximately 40 genes. We investigated the physiological roles of Fur-regulated genes by the construction of null mutations in 14 transcription units known or predicted to function in siderophore biosynthesis or iron uptake. We demonstrate that ywbLMN, encoding an elemental iron uptake system orthologous to the copper oxidase-dependent Fe(III) uptake system of Saccharomyces cerevisiae, is essential for growth in low iron minimal medium lacking citric acid. 2,3-Dihydroxybenzoyl-glycine (Itoic acid), the siderophore precursor produced by laboratory strains of B. subtilis, is of secondary importance. In the presence of citrate, the YfmCDEF ABC transporter is required for optimal growth. B. subtilis is unable to grow in minimal medium containing the iron chelator EDDHA unless the ability to synthesize the intact bacillibactin siderophore is restored (by the introduction of a functional sfp gene) or exogenous siderophores are provided. Utilization of the catecholate siderophores bacillibactin and enterobactin requires the FeuABC importer and the YusV ATPase. Utilization of hydroxamate siderophores requires the FhuBGC ABC transporter together with the FhuD (ferrichrome) or YxeB (ferrioxamine) substrate-binding proteins. Growth with schizokinen or arthrobactin is at least partially dependent on the YfhA YfiYZ importer and the YusV ATPase. We have also investigated the effects of a fur mutation on the proteome and documented the derepression of 11 Fur-regulated proteins, including a newly identified thioredoxin reductase homolog, YcgT.

Overexpression of wheat ferritin gene TaFER-5B enhances tolerance to heat stress and other abiotic stresses associated with the ROS scavenging.

PubMed

Zang, Xinshan; Geng, Xiaoli; Wang, Fei; Liu, Zhenshan; Zhang, Liyuan; Zhao, Yue; Tian, Xuejun; Ni, Zhongfu; Yao, Yingyin; Xin, Mingming; Hu, Zhaorong; Sun, Qixin; Peng, Huiru

2017-01-14

The yield of wheat (Triticum aestivum L.), an important crop, is adversely affected by heat stress in many regions of the world. However, the molecular mechanisms underlying thermotolerance are largely unknown. A novel ferritin gene, TaFER, was identified from our previous heat stress-responsive transcriptome analysis of a heat-tolerant wheat cultivar (TAM107). TaFER was mapped to chromosome 5B and named TaFER-5B. Expression pattern analysis revealed that TaFER-5B was induced by heat, polyethylene glycol (PEG), H 2 O 2 and Fe-ethylenediaminedi(o-hydroxyphenylacetic) acid (Fe-EDDHA). To confirm the function of TaFER-5B in wheat, TaFER-5B was transformed into the wheat cultivar Jimai5265 (JM5265), and the transgenic plants exhibited enhanced thermotolerance. To examine whether the function of ferritin from mono- and dico-species is conserved, TaFER-5B was transformed into Arabidopsis, and overexpression of TaFER-5B functionally complemented the heat stress-sensitive phenotype of a ferritin-lacking mutant of Arabidopsis. Moreover, TaFER-5B is essential for protecting cells against heat stress associated with protecting cells against ROS. In addition, TaFER-5B overexpression also enhanced drought, oxidative and excess iron stress tolerance associated with the ROS scavenging. Finally, TaFER-5B transgenic Arabidopsis and wheat plants exhibited improved leaf iron content. Our results suggest that TaFER-5B plays an important role in enhancing tolerance to heat stress and other abiotic stresses associated with the ROS scavenging.

Studies on the effect of divalent metal ions on exfoliative toxins from Staphylococcus hyicus: indications of ExhA and ExhB being metalloproteins.

PubMed

Andresen, L O

1999-04-01

The exfoliative toxins ExhA and ExhB produced by Staphylococcus hyicus strains NCTC10350 and 1289D-88, respectively, were investigated with regard to the effect of divalent metal ions on toxin production as measured in indirect enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies. Data were obtained as endpoint titer values and used as semiquantitative measures for the amount of exfoliative toxin detected in culture supernatants. It was shown that the endpoint titers of ExhA in supernatants from cultures of strain NCTC10350 grown in the presence of 0.5 mM CaCl2, Cu(NO3)2 or ZnSO4 were higher compared to titers obtained by growth in medium supplemented with a number of other divalent metal salts. The titer of ExhB as determined in the indirect ELISA was increased by addition of 0.5 mM CoCl2, Cu(NO3)2 or CuSO4 to the growth medium. When ExhA or ExhB, prepared without addition of metal salt to the liquid growth medium, was subsequently incubated with 25 mM of Co2+, Cu2+ or Zn2+, the endpoint titers of the toxins were increased. Dialysis of ExhA and ExhB prepared with Zn2+ and Co2+, respectively, against certain metal chelators, resulted in a reduction of the titer determined in ELISA. Other metal chelators had varied effect in the detection of the toxins in ELISA. It was, however, not possible to restore the recognition of toxins by the monoclonal antibodies by incubation of EDDHA-dialyzed toxin preparations with Co2+, Cu2+ or Zn2+. The results of this study suggest that ExhA and ExhB are metalloproteins.

Mobility and leachability of zinc in two soils treated with six organic zinc complexes.

PubMed

Alvarez, J M; Novillo, J; Obrador, A; López-Valdivia, L M

2001-08-01

A study of soil columns was conducted to evaluate Zn movement potential in two reconstructed soil profiles. Zn-phenolate, Zn-EDDHA, Zn-EDTA, Zn-lignosulfonate, Zn-polyflavonoid, and Zn-heptagluconate were applied in the upper zone of the column. The different physicochemical properties of the two soils and the micronutrient source may influence Zn leaching, the distribution of Zn among soil fractions, and the Zn available to the plant in the depth of the layers. In Aquic Haploxeralf soil, the application of six fertilizers produced little migration and very small leaching of Zn in the soil profiles. In Calcic Haploxeralf soil, Zn-EDTA migrated and was distributed throughout the soil columns. This Zn chelate produces a loss of Zn by leaching, which was 36% of the added Zn. In the latter soil, Zn leached very little with the other five fertilizer treatments. The same as for these organic Zn complexes, the retention of added Zn indicated the potential of metal accumulation in the A(p) horizons of the two soil profiles. A large portion of applied Zn was available to plants [diethylenetriaminepentaacetic acid (DTPA) and Mehlich-3 extractable Zn] in the depths reached by the different commercial formulations. The relationship between the two methods was highly significant (Mehlich-3-Zn = 1.25 + 1.13 DTPA-Zn, R(2) = 99.19%). When Zn was added as Zn-EDTA, the amounts of the most labile fractions (water-soluble plus exchangeable and organically complexed Zn) increased throughout the entire profile column in comparison with the control columns, although in the B(t) horizon of the Aquic Haploxeralf soil they increased only slightly.

Revisiting the iron pools in cucumber roots: identification and localization.

PubMed

Kovács, Krisztina; Pechoušek, Jiří; Machala, Libor; Zbořil, Radek; Klencsár, Zoltán; Solti, Ádám; Tóth, Brigitta; Müller, Brigitta; Pham, Hong Diep; Kristóf, Zoltán; Fodor, Ferenc

2016-07-01

Fe deficiency responses in Strategy I causes a shift from the formation of partially removable hydrous ferric oxide on the root surface to the accumulation of Fe-citrate in the xylem. Iron may accumulate in various chemical forms during its uptake and assimilation in roots. The permanent and transient Fe microenvironments formed during these processes in cucumber which takes up Fe in a reduction based process (Strategy I) have been investigated. The identification of Fe microenvironments was carried out with (57)Fe Mössbauer spectroscopy and immunoblotting, whereas reductive washing and high-resolution microscopy was applied for the localization. In plants supplied with (57)Fe(III)-citrate, a transient presence of Fe-carboxylates in removable forms and the accumulation of partly removable, amorphous hydrous ferric oxide/hydroxyde have been identified in the apoplast and on the root surface, respectively. The latter may at least partly be the consequence of bacterial activity at the root surface. Ferritin accumulation did not occur at optimal Fe supply. Under Fe deficiency, highly soluble ferrous hexaaqua complex is transiently formed along with the accumulation of Fe-carboxylates, likely Fe-citrate. As (57)Fe-citrate is non-removable from the root samples of Fe deficient plants, the major site of accumulation is suggested to be the root xylem. Reductive washing results in another ferrous microenvironment remaining in the root apoplast, the Fe(II)-bipyridyl complex, which accounts for ~30 % of the total Fe content of the root samples treated for 10 min and rinsed with CaSO4 solution. When (57)Fe(III)-EDTA or (57)Fe(III)-EDDHA was applied as Fe-source higher soluble ferrous Fe accumulation was accompanied by a lower total Fe content, confirming that chelates are more efficient in maintaining soluble Fe in the medium while less stable natural complexes as Fe-citrate may perform better in Fe accumulation.

Determination of suitable chemical extraction methods for the available iron content of brown forest soils in Turkey

NASA Astrophysics Data System (ADS)

Adiloglu, Aydin

2006-09-01

The aim of this research was to determine the available iron (Fe) content of brown forest soils of Edirne Province and the most suitable chemical extraction method. Eight chemical extraction methods (the 0.005 M DTPA + 0.01 M CaCl2 + 0.1 MTEA, 0.05 M HCl + 0.012 M H2SO4, 1 M NH4OAc (pH: 4.8), 0.01 M EDTA + 1 M NH4OAc, 1 M MgCl2, 0.01 M EDTA + 1 M (NH4)2CO3, 0.005 M DTPA + 1 M NH4HCO3, and 0.001 M EDDHA methods) and six biological indices (the dry matter yield, Fe concentration, Fe uptake, relative dry matter yield, relative Fe concentration, and relative Fe uptake) were compared. The biological indices were determined with barley (Hordeum vulgare L.) grown under greenhouse conditions. At the end of the experiment, the highest correlation coefficients (r) were determined to be between the 0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA method and the biological indices and between the 0.005 M DTPA + 1 M NH4HCO3 method and the biological indices. The corresponding correlation coefficients (r) for the 0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA method and the six biological indices were 0.621**, 0.823**, 0.810** 0.433**, 0.558**, and 0.640**, respectively. For the 0.005 M DTPA + 1 M NH4HCO3 method, these coefficients were equal to 0.618**, 0.520**, 0.679**, 0.521**, 0.492**, and 0.641**, respectively (** indicate the validity of the relationships at p < 0.01) These extraction methods, out of all the methods tested, were suggested for the determination of the available Fe content of the brown forest soils.

Physiological and molecular genetic evaluation of the dechlorination agent, pyridine-2,6-bis(monothiocarboxylic acid) (PDTC) as a secondary siderophore of Pseudomonas.

PubMed

Lewis, Thomas A; Leach, Lynne; Morales, Sergio; Austin, Paula R; Hartwell, Hadley J; Kaplan, Benjamin; Forker, Cynthia; Meyer, Jean-Marie

2004-02-01

The bacterial metabolite and transition metal chelator pyridine-2,6-dithiocarboxylic acid (PDTC), promotes a novel and effective means of dechlorination of the toxic and carcinogenic pollutant, carbon tetrachloride. Pyridine-2,6-dithiocarboxylic acid has been presumed to act as a siderophore in the Pseudomonas strains known to produce it. To explore further the physiological function of PDTC production, we have examined its regulation, the phenotype of PDTC-negative (pdt) mutants, and envelope proteins associated with PDTC in P. putida strain DSM 3601. Aspects of the regulation of PDTC production and outer membrane protein composition were consistent with siderophore function. Pyridine-2,6-dithiocarboxylic acid production was coordinated with production of the well-characterized siderophore pyoverdine; exogenously added pyoverdine led to decreased PDTC production, and added PDTC led to decreased pyoverdine production. Positive regulation of a chromosomal pdtI-xylE transcriptional fusion, and of a 66 kDa outer membrane protein (IROMP), was seen in response to exogenous PDTC. Tests with transition metal chelators indicated that PDTC could provide a benefit under conditions of metal limitation; the loss of PDTC biosynthetic capacity caused by a pdtI transposon insertion resulted in increased sensitivity to 1,10-phenanthroline, a chelator that has high affinity for a range of divalent transition metals (e.g. Fe(2+), Cu(2+), Zn(2+)). Exogenously added PDTC could also suppress a phenotype of pyoverdine-negative (Pvd-) mutants, that of sensitivity to EDDHA, a chelator with higher affinity and specificity for Fe(3+). Measurement of 59Fe incorporation showed uptake from 59Fe:PDTC by DSM 3601 grown in low-iron medium, but not by cells grown in high iron medium, or by the pdtI mutant, which did not show expression of the 66 kDa envelope protein. These data verified a siderophore function for PDTC, and have implicated it in the uptake of transition metals in addition to iron.

Variation and inheritance of iron reductase activity in the roots of common bean (Phaseolus vulgaris L.) and association with seed iron accumulation QTL.

PubMed

Blair, Matthew W; Knewtson, Sharon Jb; Astudillo, Carolina; Li, Chee-Ming; Fernandez, Andrea C; Grusak, Michael A

2010-10-05

Iron deficiency anemia is a global problem which often affects women and children of developing countries. Strategy I plants, such as common bean (Phaseolus vulgaris L.) take up iron through a process that involves an iron reduction mechanism in their roots; this reduction is required to convert ferric iron to ferrous iron. Root absorbed iron is critical for the iron nutrition of the plant, and for the delivery of iron to the shoot and ultimately the seeds. The objectives of this study were to determine the variability and inheritance for iron reductase activity in a range of genotypes and in a low × high seed iron cross (DOR364 x G19833), to identify quantitative trait loci (QTL) for this trait, and to assess possible associations with seed iron levels. The experiments were carried out with hydroponically grown plants provided different amounts of iron varying between 0 and 20 μM Fe(III)-EDDHA. The parents, DOR364 and G19833, plus 13 other cultivated or wild beans, were found to differ in iron reductase activity. Based on these initial experiments, two growth conditions (iron limited and iron sufficient) were selected as treatments for evaluating the DOR364 × G19833 recombinant inbred lines. A single major QTL was found for iron reductase activity under iron-limited conditions (1 μM Fe) on linkage group b02 and another major QTL was found under iron sufficient conditions (15 μM Fe) on linkage group b11. Associations between the b11 QTL were found with several QTL for seed iron. Genes conditioning iron reductase activity in iron sufficient bean plants appear to be associated with genes contributing to seed iron accumulation. Markers for bean iron reductase (FRO) homologues were found with in silico mapping based on common bean synteny with soybean and Medicago truncatula on b06 and b07; however, neither locus aligned with the QTL for iron reductase activity. In summary, the QTL for iron reductase activity under iron limited conditions may be useful in environments where beans are grown in alkaline soils, while the QTL for iron reductase under sufficiency conditions may be useful for selecting for enhanced seed nutritional quality.

Rates of cuticular penetration of chelated Fe(III): role of humidity, concentration, adjuvants, temperature, and type of chelate.

PubMed

Schönherr, Jörg; Fernández, Victoria; Schreiber, Lukas

2005-06-01

Time courses of cuticular penetration of FeCl3 and Fe(III) complexes of citric acid, EDTA, EDDHA (Sequestrene 138Fe), imidodisuccinic acid (IDHA), and ligninsulfonic acid (Natrel) were studied using astomatous cuticular membranes (CMs) isolated from Populus x canescens leaves. At 100% relative humidity, the Fe(III) chelates disappeared exponentially with time from the surface of the CMs; that is, penetration was a first-order process that can be described using rate constants or half-times of penetration (t(1/2)). Half-times ranged from 20 to 30 h. At 90% humidity, penetration rates were insignificant with the exception of Natrel, for which t(1/2) amounted to 58 h. Rate constants were independent of temperature (15, 25, and 35 degrees C). Permeability decreased with increasing Fe chelate concentration (IDHA and EDTA). At 100% humidity, half-times measured with FeIDHA were 11 h (2 mmol L(-1)), 17 h (10 mmol L(-1)) and 36 h (20 mmol L(-1)), respectively. In the presence of FeEDTA, penetration of CaCl2 was slowed greatly. Half-times for penetration of CaCl2, which were 1.9 h in the absence of FeEDTA, rose to 3.12 h in the presence of an equimolar concentration of EDTA and 13.3 h when the FeEDTA concentration was doubled. Hence, Fe chelates reduced permeability of CMs to CaCl2 and to the Fe chelates themselves. It is suggested that Fe chelates reduced the size of aqueous pores. This view is supported by the fact that rate constants for calcium salts were about 5 times higher than for Fe chelates with the same molecular weights. Adding Tween 20 (5 g L(-1)) as a humectant did not increase permeability to FeIDHA at 90% humidity and below, while addition of glycine betaine did. Penetration of FeCl3 applied at 5 g L(-1) (pH 1.5) was not a first order process as rate constants decreased rapidly with time. Only 2% of the dose penetrated during the first 2 h and less than that in the subsequent 8 h. Recovery was only 70%. This was attributed to the formation of insoluble Fe hydroxide precipitates on CMs. These results explain why in the past foliar application of Fe compounds had limited success. Inorganic Fe salts are instable and phytotoxic because of low pH, while Fe chelates penetrate slowly and 100% humidity is required for significant penetration rates. Concentrations as low as reasonably possible should be used. These physical facts are expected to apply to stomatous leaf surfaces as well, but absolute rates probably depend on leaf age and plant species. High humidity in stagnant air layers may favor penetration rates across stomatous leaf surfaces when humidity in bulk air is below 100%.