The Experts below are selected from a list of 513 Experts worldwide ranked by ideXlab platform
Jinmao You - One of the best experts on this subject based on the ideXlab platform.
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A simple and sensitive HPLC method based on pre-column fluorescence labelling for multiple classes of plant growth regulator determination in food samples
Food Chemistry, 2015Co-Authors: Shucheng Liu, Lian Xia, Guang Chen, Zhiwei Sun, Jinmao YouAbstract:The determination of trace plant growth regulator (PGR) has received more and more attentions in the field of phytophysiology and food safety. But the simple and sensitive method for simultaneously analysing multiple classes of PGR remains poorly investigated. In this study, a new pre-column fluorescence labelling method using 2-(11H-benzo[a]carbazol-11-yl)-ethyl-4- methylbenzenesulfonate (BCETS) as the labelling reagent has been developed for simultaneous determination of seven PGRs (i.e., indole-3-acetic Acid, 3-indolybutyric Acid, 3-indolepropionic Acid, jasmonic Acid, gibberellin A3, 1-Naphthylacetic Acid and 2-naphthaleneacetic Acid) by HPLC with fluorescent detection (FLD). The proposed method offered the LOD of 0.34-0.73 ng/mL for seven PGRs, which were significantly lower than the reported methods. The crude extract without complex pre-treatments and purification was directly labelled by BCETS and analysed by HPLC-FLD, which facilitates the high-throughput sample screening. This method was proven to be inexpensive, simple, selective, sensitive, accurate and reliable for trace PGR determination. © 2014 Elsevier Ltd. All rights reserved.
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determination of multiple phytohormones in fruits by high performance liquid chromatography with fluorescence detection using dispersive liquid liquid microextraction followed by precolumn fluorescent labeling
Journal of Separation Science, 2015Co-Authors: Guang Chen, Jinmao You, Shucheng Liu, Xiaojian Kong, Weiheng KongAbstract:Plant hormone determination in food matrices has attracted more and more attention because of their potential risks to human health. However, analytical methods for the analysis of multiple plant hormones remain poorly investigated. In the present study, a convenient, selective, and ultrasensitive high-performance liquid chromatography method for the simultaneous determination of multiple classes of plant hormones has been developed successfully using dispersive liquid-liquid microextraction followed by precolumn fluorescent labeling. Eight plant hormones in fruits including jasmonic Acid, 12-oxo-phytodienoic Acid, indole-3-acetic Acid, 3-indolybutyric Acid, 3-indolepropionic Acid, gibberellin A(3), 1-Naphthylacetic Acid, and 2-naphthaleneacetic Acid were analyzed by this method. The conditions employed for dispersive liquid-liquid microextraction were optimized systematically. The linearity for all plant hormones was found to be >0.9993 (R-2 values). This method offered low detection limits of 0.19-0.44 ng/mL (at a signal-to-noise ratio of 3), and method accuracies were in the range of 92.32-103.10%. The proposed method was applied to determine plant hormones in five kinds of food samples, and this method can achieve a short analysis time, low threshold levels of detection, and a high specificity for the analysis of targeted plant hormones present at trace level concentrations in complex matrices.
Lorenzo Lamattina - One of the best experts on this subject based on the ideXlab platform.
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nitric oxide triggers phosphatidic Acid accumulation via phospholipase d during auxin induced adventitious root formation in cucumber
Plant Physiology, 2008Co-Authors: Maria Luciana Lanteri, Ana M Laxalt, Lorenzo LamattinaAbstract:Auxin and nitric oxide (NO) play fundamental roles throughout plant life. NO is a second messenger in auxin signal transduction leading to root developmental processes. The mechanisms triggered by auxin and NO that direct adventitious root (AR) formation are beginning to be unraveled. The goal of this work was to study phospholipid (PL) signaling during the auxin- and NO-induced AR formation in cucumber (Cucumis sativus) explants. Explants were labeled with 32P-inorganic phosphate and treated with the auxins indole-3-acetic Acid or 1-Naphthylacetic Acid, or the NO donor S-nitroso N-acetyl penicillamine, in the presence or absence of the specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. PLs were separated by thin-layer chromatography and quantified. We report that the signaling PLs phosphatidic Acid (PA), phosphatidylinositol phosphate, and phosphatidylinositol bisphosphate accumulated within 1 min after auxin or NO treatment. Both auxin and NO evoked similar and transient time course responses, since signaling PLs returned to control levels after 20 or 30 min of treatment. The results indicate that auxin relies on NO in inducing PA, phosphatidylinositol phosphate, and phosphatidylinositol bisphosphate accumulation. Furthermore, we demonstrate that auxin and NO trigger PA formation via phospholipase D (PLD) activity. Explants treated for 10 min with auxin or NO displayed a 200% increase in AR number compared with control explants. In addition, PLD activity was required for the auxin- and NO-induced AR formation. Finally, exogenously applied PA increased up to 300% the number of ARs. Altogether, our data support the idea that PLD-derived PA is an early signaling event during AR formation induced by auxin and NO in cucumber explants.
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Nitric oxide plays a central role in determining lateral root development in tomato
Planta, 2004Co-Authors: Natalia Correa-aragunde, Magdalena Graziano, Lorenzo LamattinaAbstract:Nitric oxide (NO) is a bioactive molecule that functions in numerous physiological processes in plants, most of them involving cross-talk with traditional phytohormones. Auxin is the main hormone that regulates root system architecture. In this communication we report that NO promotes lateral root (LR) development, an auxin-dependent process. Application of the NO donor sodium nitroprusside (SNP) to tomato ( Lycopersicon esculentum Mill.) seedlings induced LR emergence and elongation in a dose-dependent manner, while primary root (PR) growth was diminished. The effect is specific for NO since the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO) blocked the action of SNP. Depletion of endogenous NO with CPTIO resulted in the complete abolition of LR emergence and a 40% increase in PR length, confirming a physiological role for NO in the regulation of root system growth and development. Detection of endogenous NO by the specific probe 4,5-diaminofluorescein diacetate (DAF-2 DA) revealed that the NO signal was specifically located in LR primordia during all stages of their development. In another set of experiments, SNP was able to promote LR development in auxin-depleted seedlings treated with the auxin transport inhibitor N-1-naphthylphthalamic Acid (NPA). Moreover, it was found that LR formation induced by the synthetic auxin 1-Naphthylacetic Acid (NAA) was prevented by CPTIO in a dose-dependent manner. All together, these results suggest a novel role for NO in the regulation of LR development, probably operating in the auxin signaling transduction pathway.
Göran Sandberg - One of the best experts on this subject based on the ideXlab platform.
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aux1 promotes lateral root formation by facilitating indole 3 acetic Acid distribution between sink and source tissues in the arabidopsis seedling
The Plant Cell, 2002Co-Authors: Alan Marchant, Rishikesh P Bhalerao, Jan Eklof, Pedro J. Casero, Malcolm J Bennett, Ilda Casimiro, Göran SandbergAbstract:Arabidopsis root architecture is regulated by shoot-derived signals such as nitrate and auxin. We report that mutations in the putative auxin influx carrier AUX1 modify root architecture as a result of the disruption in hormone transport between indole-3-acetic Acid (IAA) source and sink tissues. Gas chromatography–selected reaction monitoring–mass spectrometry measurements revealed that the aux1 mutant exhibited altered IAA distribution in young leaf and root tissues, the major IAA source and sink organs, respectively, in the developing seedling. Expression studies using the auxin-inducible reporter IAA2::uidA revealed that AUX1 facilitates IAA loading into the leaf vascular transport system. AUX1 also facilitates IAA unloading in the primary root apex and developing lateral root primordium. Exogenous application of the synthetic auxin 1-Naphthylacetic Acid is able to rescue the aux1 lateral root phenotype, implying that root auxin levels are suboptimal for lateral root primordium initiation in the mutant.
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aux1 promotes lateral root formation by facilitating indole 3 acetic Acid distribution between sink and source tissues in the arabidopsis seedling
The Plant Cell, 2002Co-Authors: Alan Marchant, Rishikesh P Bhalerao, Jan Eklof, Pedro J. Casero, Malcolm J Bennett, Ilda Casimiro, Göran SandbergAbstract:Arabidopsis root architecture is regulated by shoot-derived signals such as nitrate and auxin. We report that mutations in the putative auxin influx carrier AUX1 modify root architecture as a result of the disruption in hormone transport between indole-3-acetic Acid (IAA) source and sink tissues. Gas chromatography–selected reaction monitoring–mass spectrometry measurements revealed that the aux1 mutant exhibited altered IAA distribution in young leaf and root tissues, the major IAA source and sink organs, respectively, in the developing seedling. Expression studies using the auxin-inducible reporter IAA2::uidA revealed that AUX1 facilitates IAA loading into the leaf vascular transport system. AUX1 also facilitates IAA unloading in the primary root apex and developing lateral root primordium. Exogenous application of the synthetic auxin 1-Naphthylacetic Acid is able to rescue the aux1 lateral root phenotype, implying that root auxin levels are suboptimal for lateral root primordium initiation in the mutant.
Nicolas Spassky - One of the best experts on this subject based on the ideXlab platform.
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preparation characterisation and properties of poly ether amide s bearing hydroxyl side groups and of their derivatives with the synthetic auxin 1 Naphthylacetic Acid
Macromolecular Chemistry and Physics, 1998Co-Authors: Milena Ignatova, Maurice Sepulchre, Nevena Manolova, Iliya Rashkov, Nicolas SpasskyAbstract:New water-soluble poly(ether-amide)s (PEA)s were synthesised by polycondensation of diethyl L-tartrate and commercial polyethers having isopropylamino end-groups (Jeffamine ED-600 or Jeffamine ED-900). PEAs were derivatised with the synthetic auxin 1-Naphthylacetic Acid (NAA). It was shown that PEA and their esters with NAA (PEA-NAA) form interpolymer complexes with polyAcids and that the complex formation is favoured by the hydrophobic NAA-residues in PEA-NAA. The hydrolysis of PEA-NAA was found to proceed mainly by cleavage of the ester bonds linking the pendant NAA-residues. The poly(ether-amide) main chain was found to be more stable than the similar poly(ether-ester) chain of poly[oxytartaroyloxypoly(oxyethylene)].
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water soluble polymers bearing biologically active residues 2 complexes of poly ether ester s with polyacrylic and polymethacrylic Acids
Macromolecular Chemistry and Physics, 1993Co-Authors: Milena Ignatova, Maurice Sepulchre, Nevena Manolova, Iliya Rashkov, Nicolas SpasskyAbstract:The complex formation between poly(acrylic Acid) (PAA) or poly(methacrylic Acid) (PMA) with poly(ether-ester)s such as poly[oxymaloyloxypoly(oxyethylene)]s (PMEGs) and poly[oxytartaroyloxypoly(oxyethylene)]s (PTEGs) as well as with their derivatives with the synthetic plant-growth regulator 1-Naphthylacetic Acid (NNA) was studied. Complex formation with PAA occurs below a critical polyether chain length for polymer-polymer complexation. This peculiarity is discussed in view of the stabilizing effect of hydrophobization resulting from intramolecular hydrogen bonding. The hydrophobic 1-naphthylacetyl groups of PMEG and PTEG esters are found to stabilize the polycomplexes even more. Derivatives with NAA as well as their complexes with PAA and PMA exhibit auxin activity.
Sonia Becedas Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous Determination of 1-Naphthylacetic Acid and Thiabendazole in Strawberry Tree Berries and Citrus Fruits by Fluorescence Spectrometry
Food Analytical Methods, 2018Co-Authors: José A. Murillo Pulgarín, Luisa F. García Bermejo, Sonia Becedas RodriguezAbstract:An accurate, sensitive spectrofluorimetric method was developed to determine 1-Naphthylacetic Acid and thiabendazole simultaneously in fruits in a simple, expeditious manner. Broadband overlap between the conventional spectra of the two compounds was resolved by using first-derivative constant-wavelength synchronous fluorescence spectrometry. The proposed method is based on the intrinsic fluorescence of the two agrochemicals in ethanol. The sensitivity and selectivity of the determination were optimized by examining the influence of various factors on the fluorescence intensity. Based on the results, analyses were performed in 30% ( v / v ) ethanol–water mixtures at a pH 4.7 adjusted with sodium citrate buffer. Using the derivative signals at 304 and 286 nm for 1-Naphthylacetic Acid and thiabendazole, respectively, provided linear calibration graphs over the range 10–100 and 30–120 ng mL^−1, and limits of detection of 1.99 and 0.17 ng mL^−1, respectively. The analytical figures of merit of the proposed method were calculated in the light of the error propagation theory. The sensitivity, repeatability, reproducibility and limits of detection obtained are acceptable for determining the two agrochemicals in strawberry tree berries and citrus fruits without the need for a time-consuming prior separation. The proposed method is simple, reliable and cost-efficient, which makes it an attractive choice for fast selective screening purposes.
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simultaneous determination of plant growth regulators 1 Naphthylacetic Acid and 2 naphthoxyacetic Acid in fruit and vegetable samples by room temperature phosphorescence
Phytochemical Analysis, 2012Co-Authors: Jose Murillo A Pulgarin, Luisa Garcia F Bermejo, Ignacio Sanchezferrer Robles, Sonia Becedas RodriguezAbstract:Introduction 1-Naphthylacetic and 2-naphthoxyacetic Acids belong to the synthetic branch of auxins. Auxins have attracted considerable interest as a subject of study by virtue of their biological and physiological significance. Their broad use as plant growth regulators has raised the need for simple, rapid, sensitive and selective analytical methods for their determination in real samples. Objective The primary aim of this work was to develop an analytical method for the simultaneous determination of 1-Naphthylacetic Acid and 2-naphthoxyacetic Acid in commercial technical formulations, tomato and various fruit types (apple, strawberry, orange and plum) by room temperature phosphorescence. Methodology Filtrated solutions of aqueous slurries from ecological fruit and tomato samples are Acidified and then extracted with dichloromethane. Once the solvent is evaporated, the dried residue is dissolved in sodium dodecyl sulphate (a micellar agent), and supplied with thallium (I) nitrate as an external heavy atom source and sodium sulphite as deoxygenation agent to enhance the ensuing phosphorescence. Results The broad-band overlapping spectra for the two analytes were resolved by first- and second-derivative phosphorescence spectrometry. Zero-crossing measurements at 488.5 nm in the first-derivative spectrum and 469.5 nm in the second derivative spectrum exhibited a linear dependence on the 2-naphthoxyacetic Acid and 1-Naphthylacetic Acid concentration, respectively. The detection limits as determined in accordance with the error propagation theory were 11.5 ng/mL for 1-Naphthylacetic Acid and 15.6 ng/mL for 2-naphthoxyacetic Acid. Conclusion The proposed method affords the determination of 1-Naphthylacetic Acid and 2-naphthoxyacetic Acid in real samples with near-quantitative recoveries from agricultural products. Copyright © 2011 John Wiley & Sons, Ltd.
