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The two-electron oxidation of 1-aminocyclopropane-l-carboxylic acid (ACC) to ethylene may proceed through a concerted or stepwise mechanism, this latter being that probably occurring in vivo. An essential feature of this reaction is the... more
The two-electron oxidation of 1-aminocyclopropane-l-carboxylic acid (ACC) to ethylene may proceed through a concerted or stepwise mechanism, this latter being that probably occurring in vivo. An essential feature of this reaction is the production of ACC-free radicals as intermediate. If these ACC-free radicals are liberated into the reaction medium, they will readily react with dissolved oxygen resulting in the formation of an ACC-derived hydroperoxide. Subsequently to the hydroperoxide formation, a decrease in the yield of ethylene and the appearance of other compounds, such as 3-hydroxypropylamide (HPA), might occur. HPA has been found not only in stepwise-type reactions, such as those mediated by peroxidase, but also in concerted reactions, such as the oxidation by hypochlorite or hydrogen peroxide. In this work we investigate the mechanism of ACC oxidation by the two kinds of reactions and discuss some physiological implications.
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Les variations dans la production d'ethylene, l'activite de l'enzyme formant l'ethylene (EFE) et les teneurs en acide 1-aminocyclopropane-1-carboxylique (ACC) ont ete etudiees a differents âges et dans differentes regions... more
Les variations dans la production d'ethylene, l'activite de l'enzyme formant l'ethylene (EFE) et les teneurs en acide 1-aminocyclopropane-1-carboxylique (ACC) ont ete etudiees a differents âges et dans differentes regions localisees le long d'hypocotyles etioles de Lupinus albus
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The enzymatic IAA-oxidase and peroxidase activities in homogenates of zones from different localizations along the etiolated hypocotyls of Lupinus albus , L are studied. In actively growing 9 day old seedlings, both activities expressed... more
The enzymatic IAA-oxidase and peroxidase activities in homogenates of zones from different localizations along the etiolated hypocotyls of Lupinus albus , L are studied. In actively growing 9 day old seedlings, both activities expressed on a per fresh weight basis, show a decreasing distribution starting from the cotyledons. The specific activities, however exhibit a bell-shaped distribution that is parallel to that of growth. At 15 days, the distribution of IAA-oxidase as well as of peroxidase, tends to be more uniform along the whole hypocotyl as a consequence of the decrease in activity in the apical zones and the increase in the basal. The activities per g fresh weight show a distribution very similar to that of growth. On the other hand, the specific activities oscillate along the hypocotyls, the highest values being in the apical (growing) and in the basa1 zones. The role of IAA-oxidase in the control of the IAA content during the hypocotyl growth is discussed.
Research Interests: Botany, Biology, Medicine, Growth, Peroxidase, and 5 moreCrecimiento, Lupinus, Hypocotyl, Lupinus albus, and etiolation
The variation in IAA-oxidase and peroxidase activities in etiolated lupine hypocotyls treated with IAA is studied. Intact plants sprayed with 10 -3 M IAA solution, show an increase of IAA-oxidase in the hypocotyls after 6 h of treatment.... more
The variation in IAA-oxidase and peroxidase activities in etiolated lupine hypocotyls treated with IAA is studied. Intact plants sprayed with 10 -3 M IAA solution, show an increase of IAA-oxidase in the hypocotyls after 6 h of treatment. After 24 h, the activity is the same as that of untreated plants. The effect of IAA varies with the age of the seedlings as well as with the localization along the hypocotyl. Only those zones with low growth or with recently stopped growth, exhibit an increase of IAA-oxidase after treatment with IAA, the increase being supressed by cicloheximide. When whole hypocotyls of different ages are incubated in IAA solutions, reproducible results are only obtained if plants are decapitated before the treatments. 24 h after decapitation IAA-oxidase decreases 30 % in relation to non decapitated seedlings. Decapitated seedling hypocotyls incubated with IAA show an increase of specific activity at 10 -4 M IAA, and a decrease at 10 -3 M IAA. Cicloheximide reinfor...
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Present paper shows a study to identify and quantify the amino acids in a protein hydrolyzate obtained in the production of Fitomas-E, a natural foliar bionutrient, growth promoter, which increases the capacity of self-defense, yields and... more
Present paper shows a study to identify and quantify the amino acids in a protein hydrolyzate obtained in the production of Fitomas-E, a natural foliar bionutrient, growth promoter, which increases the capacity of self-defense, yields and crop quality of treated cultures, using the HPLC chromatographic technique and pre-column derivatization with o-phthalaldehyde (OPA) with one modification. The column was a Lichrospher 100 RP-18 (5 m) and UV detection at 338 nm at a temperature between 30 and 35 °C. In the amino acid composition found in the product, were highlighted as major amino acids: alanine, glutamine, phenylalanine, tryptophan, valine, leucine and lysine. It can be concluded that this technique was appropriate to accelerate and improve sensitivity for the determination of amino acids profile in the studied hydrolyzate.
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The possible influence of ethylene on growth was investigated in etiolated lupin (Lupinus albus L.) hypocotyls. The treatment of lupin seeds with either 1-aminocyclopropane-1-carboxylic acid (ACC) or ethephon led to a shorter and thicker... more
The possible influence of ethylene on growth was investigated in etiolated lupin (Lupinus albus L.) hypocotyls. The treatment of lupin seeds with either 1-aminocyclopropane-1-carboxylic acid (ACC) or ethephon led to a shorter and thicker seedling, ethephon being the most effective in causing this effect. In both cases, the effects on growth could be drastically prevented by pretreating the seeds with silver thiosulphate, a potent inhibitor of ethylene action. Furthermore, when lupin seeds were incubated in silver thiosulphate a transient reduction in both length and hypocotyl diameter was also observed. The results suggest that ethylene is implicated in the establishment of the final length and size of the lupin hypocotyl.
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Lupin seeds treated with 1-amino-cyclopropane-1-carboxylic acid (ACC) or2-chloroethylphosphonic acid (CEPA) produced hypocotyls showing a typicalethylene growth response (reduced elongation and increased thickness), whichcould be... more
Lupin seeds treated with 1-amino-cyclopropane-1-carboxylic acid (ACC) or2-chloroethylphosphonic acid (CEPA) produced hypocotyls showing a typicalethylene growth response (reduced elongation and increased thickness), whichcould be efficiently counteracted by the presence of silver thiosulfate (STS).The fact that ACC and CEPA stimulated the ethylene produced in different zonesalong the hypocotyls suggests that these compounds, which are stored in theseeds during treatment, were transported
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Fermentation broth and biomass from three strains of Botryodiplodia theobromae were characterized by high performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS) method, in order to quantify different... more
Fermentation broth and biomass from three strains of Botryodiplodia theobromae were characterized by high performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS) method, in order to quantify different phytohormones and to identify amino acid conjugates of jasmonic acid (JA) present in fermentation broths. A liquid-liquid extraction with ethyl acetate was used as sample preparation. The separation was carried out on a C18 reversed-phase HPLC column followed by analysis via ESI-MS/MS. The multiple reaction monitoring mode was used for quantitative measurement. For the first time, indole-3-acetic acid, indole-3-propionic acid, indole-3-butyric acid and JA were identified and quantified in the ethyl acetate extracts from the biomass, after the separation of mycelium from supernatant. The fermentation broths showed significantly higher levels of JA in relation to the other phytohormones. This is the first report of the presence of gibberellic acid, abscisic acid, salicylic acid and the cytokinins zeatin, and zeatin riboside in fermentation broths of Botryodiplodia sp. The presence of JA-serine and JA-threonine conjugates in fermentation broth was confirmed using HPLC-ESI tandem mass spectrometry in negative ionization mode, while the occurrence of JA-glycine and JA-isoleucine conjugates was evidenced with the same technique but with positive ionization. The results demonstrated that the used HPLC-ESI-MS/MS method was effective for analysing phytohormones in fermentation samples.
Research Interests: Chemistry, Technology, Chromatography, Medicine, Biological Sciences, and 12 morePlant Growth Regulators, Tandem Mass Spectrometry, Abscisic Acid, High Performance Liquid Chromatography, High Pressure Liquid Chromatography, Fermentation, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Ascomycota, Gibberellins, Electrospray Ionization, Oxylipins, and zeatin
Research Interests: Horticulture, Biology, Cultivar, Cutting, Auxin, and 4 moreCold Storage, Carnation, Sowing, and Horticultural production
Novel cDNA clones encoding putative auxin influx and efflux carriers have been isolated and characterized from etiolated lupin (Lupinus albus L) hypocotyls. The full length of LaAUX1 and LaPIN1 and the partial length of LaPIN3 were... more
Novel cDNA clones encoding putative auxin influx and efflux carriers have been isolated and characterized from etiolated lupin (Lupinus albus L) hypocotyls. The full length of LaAUX1 and LaPIN1 and the partial length of LaPIN3 were obtained and the deduced amino acid sequence revealed a high degree of identity with the corresponding auxin carrier proteins from several species. The expression of these genes depended on the tissue, the hypocotyl zone and seedling age. LaAUX1 and LaPIN3 were expressed in stele and outer tissues, while LaPIN1 was restricted to the stele. From the above-mentioned results and taking into account the role proposed for the efflux carrier PIN1, it is suggested that LaPIN1 could mediate the basipetal auxin transport already described in this organ. LaAUX1 might facilitate auxin influx in the transport cells. The expression of the three genes decreased down the hypocotyl. The basipetally decreasing gradient in the expression of LaPIN1 coincides with previous results showing a similar gradient in the intensity and polarity of auxin transport. The decisive role ascribed to PIN1 in polar auxin transport due to its localization in the basal end of transporting cells and the existence of such a gradient in the expression of LaPIN1 support the hypothesis of a barrier effect (generated by decreasing auxin transport) previously proposed by our research group as being responsible for the auxin gradient, which controls the growth pattern in etiolated lupin hypocotyls.
Research Interests: Plant Biology, Biology, Medicine, Seedling, Auxin, and 15 moreLupinus, Amino Acid Sequence, Stele, PLANT PROTEINS, Polar Auxin Transport, Planta, Full Length Movies, Gene expression profiling, Hypocotyl, Molecular Sequence Data, cDNA cloning, reverse transcriptase polymerase chain reaction, Lupinus albus, etiolation, and Growth pattern
Tomato crop productivity under salinity can be improved by grafting cultivars onto salt-tolerant wild relatives, thus mediating the supply of root-derived ionic and hormonal factors that regulate leaf area and senescence. A tomato... more
Tomato crop productivity under salinity can be improved by grafting cultivars onto salt-tolerant wild relatives, thus mediating the supply of root-derived ionic and hormonal factors that regulate leaf area and senescence. A tomato cultivar was grafted onto rootstocks from a population of recombinant inbred lines (RILs) derived from a Solanum lycopersicum x Solanum cheesmaniae cross and cultivated under moderate salinity (75 mM NaCl). Concentrations of Na(+), K(+) and several phytohormones [abscisic acid (ABA); the cytokinins (CKs) zeatin, Z; zeatin riboside, ZR; and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC)] were analysed in leaf xylem sap in graft combinations of contrasting vigour. Scion leaf area correlated with photosystem II (PSII) efficiency (F(v)/F(m)) and determined fruit productivity. Xylem K(+) (but not Na(+)), K(+)/Na(+), the active CK Z, the ratio with its storage form Z/ZR and especially the ratio between CKs and ACC (Z/ACC and Z + ZR/ACC) were positively loaded into the first principal component (PC) determining both leaf growth and PSII efficiency. In contrast, the ratio ACC/ABA was negatively correlated with leaf biomass. Although the underlying physiological mechanisms by which rootstocks mediate leaf area or chlorophyll fluorescence (and thus influence tomato salt tolerance) seem complex, a putative potassium-CK interaction involved in regulating both processes merits further attention.
Research Interests: Principal Component Analysis, Biology, Medicine, Biological Sciences, Salinity, and 15 moreChlorophyll Fluorescence, Plant Growth Regulators, Crop Production, Cultivar, Potassium, Abscisic Acid, Sodium, Plant cell, Salt tolerant plants, Rootstock, Leaf Area, Lycopersicon esculentum, Cytokinins, Plant Leaves, and leaf senescence
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Research Interests: Botany, Plant Biology, Biology, Medicine, Plant Growth Regulators, and 15 moreCutting, Plant Roots, Abscisic Acid, Auxin, Carbohydrate metabolism, Carnation, PLANT PROTEINS, Biochemistry and cell biology, Salicylates, Cytokinins, Jasmonic Acid, Horticultural production, reverse transcriptase polymerase chain reaction, Tissue culture techniques, and Cytokinin
ABSTRACT During oxidation of indole-3-acetic acid catalyzed by horseradish peroxidase, indole-3-aldehyde and 3-hydroxymethayloxindole cease to be produced a few minutes after initiation of the reaction even though IAA is still being... more
ABSTRACT During oxidation of indole-3-acetic acid catalyzed by horseradish peroxidase, indole-3-aldehyde and 3-hydroxymethayloxindole cease to be produced a few minutes after initiation of the reaction even though IAA is still being consumed. At the same time an increased accumulation of indole-3-methanol is observed and the ratio of oxygen to indole-3-acetic acid consumed becomes less than unity. Indole-3-niethanol can be a substrate for horseradish peroxidase provided that H2O2 is present. In this reaction, indole-3-aldehyde but not 3-hydroxymethyloxindole is formed. H2O2 is not merely an activating agent for the enzyme but also a true oxidant because it is consumed stoichiometrically (1 mol of H2O2 per mol of indole-3-methanol) and the reaction is independent of the presence of oxygen. Indole-3-methanol is proposed as an intermediate in the process of oxidation of indole-3-acetic acid into indole-3-al-denyde, the second step of which requires peroxide as an oxidant.
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The involvement of polar auxin transport (PAT) on the growth of light-grown seedlings and rooting is generally accepted, while the role of auxin and PAT on the growth of dark-grown seedlings is subject to controversy. To further... more
The involvement of polar auxin transport (PAT) on the growth of light-grown seedlings and rooting is generally accepted, while the role of auxin and PAT on the growth of dark-grown seedlings is subject to controversy. To further investigate this question, we have firstly studied the influence of NPA, a known inhibitor of PAT, on the rooting and growth of etiolated Lupinus albus hypocotyls. Rooting was inhibited when the basal ends of de-rooted seedlings were immersed in 100 micro m NPA but was partially restored after immersion in NPA + auxin. However, NPA applied to de-rooted seedlings or the roots of intact seedlings did not inhibit hypocotyl growth. It was taken up and distributed along the organ, and actually inhibited the basipetal transport of ((3)H)-IAA applied to isolated hypocotyl sections. Since the apex is the presumed auxin source for hypocotyl growth and rooting, and the epidermis is considered the limiting factor in auxin-induced growth, the basipetal and lateral auxin movement (LAM) after application of ((3)H)-IAA to decapitated seedlings were studied, in an attempt to evaluate the role of PAT and LAM in the provision of auxin to competent cells for growth and rooting. Local application of ((3)H)-IAA to the stele led to the basipetal transport of auxin in this tissue, but the process was drastically reduced when roots were immersed in NPA since no radioactivity was detected below the apical elongation region of the hypocotyl. LAM from the stele to the cortex and the epidermis occurred during basipetal transport, since radioactivity in these tissues increased as transport time progressed. Radioactivity on a per FW basis in the epidermis was 2-4 times higher than in the cortex, which suggests that epidermal cells acted as a sink for LAM. NPA did not inhibit LAM along the elongation region. These results suggest that while PAT was essential for rooting, LAM from the PAT pathway to the auxin-sensitive epidermal cells could play a key role in supplying auxin for hypocotyl elongation in etiolated lupin seedlings.
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ABSTRACT The free indole-3-acetic acid (IAA) in methanolic extracts of etiolated hypocotyls of lupin (Lupinus albus L., from Bari, Italy) was determined by fluorimetry. The distribution of IAA along the hypocotyls was parallel to the... more
ABSTRACT The free indole-3-acetic acid (IAA) in methanolic extracts of etiolated hypocotyls of lupin (Lupinus albus L., from Bari, Italy) was determined by fluorimetry. The distribution of IAA along the hypocotyls was parallel to the growth, but when growth ceased oscillations occurred in the auxin level. These oscillations could be related to processes of differentiation mediated by IAA. The oscillations did not obey any impulses from the apex, since the application of [1-14C]-IAA to decapitated plants gives a distribution of radioactivity which also presents an undulatory pattern. Our results support the hypothesis that morphogenesis can be regulated by information transmitted by the translocation of waves of auxin.
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ABSTRACT The influence of two oxidants. (H202 and m-chloroperoxibenzoic acid. (mCPBA)) and two reductants. (ascorbate. (ASC) and glutathione. (GSH)) on growth and rooting of the etiolated Lupinus albus L. hypocotyls has been studied.... more
ABSTRACT The influence of two oxidants. (H202 and m-chloroperoxibenzoic acid. (mCPBA)) and two reductants. (ascorbate. (ASC) and glutathione. (GSH)) on growth and rooting of the etiolated Lupinus albus L. hypocotyls has been studied. Lupin seedlings were derooted and the hypocotyls treated for 24 h with aqueous solutions containing different concentrations. (from 10 µM to 50 mM) of the above compounds. The hypocotyl length and the number and length of the adventitious roots were determined periodically. All the assayed compounds showed a capacity to inhibit growth and rooting of the hypocotyls, the effect being dependent on the compound and its concentration. As a rule, the greater the concentration, the higher the inhibition. The compounds can be classified from higher to lower efficiency as inhibitors as follows: mCPBA, GSH, ASC and H2O2; therefore, inhibitory efficiency is seemingly dependent on the compound per se rather than on its redox nature. The higher effectiveness as inhibitor of mCPBA and GSH is discussed in light of their capacity to inactivate enzymes such as peroxidases, which are involved in plant development and in the protective mechanism against oxidative stress. The fact that younger, actively growing tissues were less sensitive than older hypocotyl tissues to the toxicity of mCPBA and GSH supports the view of a changing endogenous redox state during growth. Data presented here suggest that regulation of the redox balance is decisive in regulating plant morphogenesis.
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... Both factors, auxins and carbohydrates, seem to be interrelated. Thus, several authors have reported that the stimulation of ARF in cuttings by indole-3-acetic acid (IAA) coincided with increased sugar availability at the site of root... more
... Both factors, auxins and carbohydrates, seem to be interrelated. Thus, several authors have reported that the stimulation of ARF in cuttings by indole-3-acetic acid (IAA) coincided with increased sugar availability at the site of root primordia development (Nanda and Jain 1972). ...
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The influence of 2,3,5-triiodobenzoic acid (TIBA) on the transport and metabolism of indolyl-3-acetic acid (IAA) was studied in etiolated lupin (Lupinus albus L) hypocotyls. Double isotope-labeled IAA [(5-3H)-IAA plus (1-14C)-IAA] was... more
The influence of 2,3,5-triiodobenzoic acid (TIBA) on the transport and metabolism of indolyl-3-acetic acid (IAA) was studied in etiolated lupin (Lupinus albus L) hypocotyls. Double isotope-labeled IAA [(5-3H)-IAA plus (1-14C)-IAA] was applied to the cut surface of decapitated seedlings. This confirmed that the species mobilized was unaltered IAA and permitted us to measure the in vivo decarboxylation of applied IAA.
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The objective of this work was to develop a simple procedure to determine the level of the plant hormone indole-3-acetic acid (IAA) in etiolated lupin hypocotyls using liquid chromatography with amperometric detection. A C18... more
The objective of this work was to develop a simple procedure to determine the level of the plant hormone indole-3-acetic acid (IAA) in etiolated lupin hypocotyls using liquid chromatography with amperometric detection. A C18 reversed-phased column was used with a potential of +0.85V applied to the carbon electrode. We used two different auxin extraction procedures from lupin hypocotyl and similar