Antonio A. Calderón

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The exogenous application of salicylic acid (SA) not only protects plants against stress, but also enhances their growth and productivity. In this study, proliferating shoots of Cistus heterophyllus subsp. carthaginensis, an endangered plant species, were incubated in the presence of 0, 10, 100, and 1,000 μM SA for a period of 2 months. Overall growth,(More)
Zygophyllum fabago is a promising species for restoring heavy metal (HM) polluted soils, although the mechanisms involved in HM tolerance in this non-model plant remain largely unknown. This paper analyses the extent to which redox-active compounds and enzymatic antioxidants in roots, stems and leaves are responsible for Pb tolerance in a metallicolous(More)
The distribution of 4 key isoflavones (luteone, genistein, 2'-hydroxygenistein and wighteone) in lupin (Lupinus albus L. cv. multolupa) hypocotyls shows a gradient that diminishes from young to old tissues. A spatial gradient occurs within the hypocotyl, and a temporal gradient in both the outermost vascular and epidermal tissues. Not only does a gradient(More)
A new and sensitive spectrophotometric assay has been developed to study and to characterize kinetically the oxidation of 4-hydroxystilbene (an analogue of the putative viniferin precursor, trans-resveratrol, directly involved in the resistance mechanism of the grapevine to fungal diseases) by peroxidase-H2O2 systems. The technique measures the overall(More)
A zymographic screening of peroxidases (EC capable of oxidizing 4-hydroxystilbene was carried out by means of the peroxidase-catalyzed oxidative coupling of 4-hydroxystilbene and 4-aminoantipyrine. This screening reveals that only a few isoperoxidases are active in oxidizing 4-hydroxystilbene to viniferin-type compounds in in vitro cultures of(More)
The oxidative stability of rosmarinic acid (alpha-O-caffeoyl-3,4-dihydroxyphenyllactic acid) in lavandin (Lavandula x intermedia) cell cultures was studied in an attempt to explain the decrease in the rosmarinic acid content of aging cell cultures, a process which is associated with the appearance of brown pigments. The oxidation of rosmarinic acid by a(More)
A zymographic assay is described for the detection of peroxidase isoenzymes oxidizing 4-hydroxystilbene following isoelectric focusing. The assay is based on coupling intermediate products of the oxidation of 4-hydroxystilbene with 4-aminoantipyrine, with resultant formation of dye complexes. Control experiments in the absence of 4-hydroxystilbene and(More)
Suspension-cultured cells of Solanum lycopersicum cv Micro-Tom were used to evaluate the effect of methyl jasmonate and cyclodextrins, separately or in combination, on the induction of defense responses. An extracellular accumulation of two sterols (isofucosterol and β-sitosterol) and taraxasterol, a common tomato fruit cuticular triterpene, were observed.(More)
Cistus heterophyllus subsp. carthaginensis is an endemic and endangered species from the SE Mediterranean coastal region of Spain. Within the framework of the efforts aiming to species conservation, in vitro culture techniques could be of interest. The aim of this study was to evaluate the antioxidant capacity of C. heterophyllus shoot cultures as a(More)
The oxidation of hydroquinone by two peroxidase (EC fractions obtained from the cells and spent medium of cell cultures of grapevine (Vitis vinifera cv Monastrell) has been studied, and their comparative efficacy (kcat/KM ratio) studied in both the H2O2-consuming and hydroquinone-consuming reactions. While the efficacy in the H2O2-consuming(More)