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Results for “SALICYLIC ACID”

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PubMed1998

Salicylic acid induces a cytosolic Ca2+ elevation in yeast.

Cytosolic free calcium ion concentration ([Ca2+]cyt) after a salicylic acid (SA)-stimulus was monitored in cells of the yeast Saccharomyces cerevisiae expressing apoaequorin, which constitutes a Ca(2+)-sensitive luminescent protein, aequorin, when combined with coelenterazine. SA induced a transient [Ca2+]cyt elevation that was dependent on the concentration of SA and pH of the SA solution. The SA-induced [Ca2+]cyt elevation was not reduced in Ca(2+)-deficient medium, suggesting that Ca2+ was mobilized from an intracellular Ca2+ store(s). Benzoic acid, butyric acid and sorbic acid did not induced a [Ca2+]cyt elevation.

Aequorin↗
PubMed1991

Morphometric studies in rectal biopsy specimens from patients with ulcerative colitis: effect of oral 5 amino salicylic acid and rectal prednisolone treatment.

Morphometric measurements were performed on rectal biopsy specimens from 10 normal control subjects and 33 patients with a relapse of distal ulcerative colitis before and after treatment for four weeks in a double blind controlled trial with oral eudragit S coated 5 amino salicylic acid (n = 12) or rectal prednisolone enemas (n = 15). Measurements were assessed using a computer aided measuring system and a counting technique. When untreated patients were compared with the control group there were significant decreases in the area and height of the surface epithelium, in the area of crypt epithelium, and in the ratios of goblet cells to epithelial cells and of surface epithelium to lamina propria. The vascular and lamina propria areas and the number of intraepithelial polymorphs were increased. Treatment with 5 amino salicylic acid and corticosteroids resulted in similar morphological improvements: there was an increase in the area and height of the surface epithelium and the ratios of surface epithelium to lamina propria and of surface to crypt cell height. The ratio of goblet cells to epithelial cells also increased after treatment, while the numbers of polymorphs in the surface and crypt epithelium and lumen decreased. In conclusion, computerised morphometry is valuable for the assessment of the treatment of patients with ulcerative colitis and that in the doses used both treatments were of similar efficacy.

Aminosalicylic Acids↗
PubMed2004

Endogenous salicylic acid protects rice plants from oxidative damage caused by aging as well as biotic and abiotic stress.

Salicylic acid (SA) is a key endogenous signal that mediates defense gene expression and disease resistance in many dicotyledonous species. In contrast to tobacco and Arabidopsis, which contain low basal levels of SA, rice has two orders of magnitude higher levels of SA and appears to be insensitive to exogenous SA treatment. To determine the role of SA in rice plants, we have generated SA-deficient transgenic rice by expressing the bacterial salicylate hydroxylase that degrades SA. Depletion of high levels of endogenous SA in transgenic rice does not measurably affect defense gene expression, but reduces the plant's capacity to detoxify reactive oxygen intermediates (ROI). SA-deficient transgenic rice contains elevated levels of superoxide and H2O2, and exhibits spontaneous lesion formation in an age- and light-dependent manner. Exogenous application of SA analog benzothiadiazole complements SA deficiency and suppresses ROI levels and lesion formation. Although an increase of conjugated catechol was detected in SA-deficient rice, catechol does not appear to significantly affect ROI levels based on the endogenous catechol data and exogenous catechol treatment. When infected with the blast fungus (Magnaporthe grisea), SA-deficient rice exhibits increased susceptibility to oxidative bursts elicited by avirulent isolates. Furthermore, SA-deficient rice is hyperresponsive to oxidative damage caused by paraquat treatment. Taken together, our results strongly suggest that SA plays an important role to modulate redox balance and protect rice plants from oxidative stress.

Catechols↗
PubMed1983

Anti-thrombotic effect of very low doses of acetyl salicylic acid in rats.

The anti-thrombotic effect of acetyl salicylic acid (ASA) was studied using the following experimental model: a silk thread was inserted in an extracorporeal shunt between the right carotid artery and the opposite jugular vein. A thrombus developed around the thread which was weighed at 10 minutes intervals. ASA inhibits the development of the thrombus at a dose of 3.1 mg/kg. When the dose was increased the anti-thrombotic effect disappeared. These results suggest that ASA may be an effective antithrombotic agent in man if the dosage is based on pharmacological data.

Animals↗
PubMed1998

Acrylic bone cements incorporating polymeric active components derived from salicylic acid: curing parameters and properties.

A methacrylic monomer derived from salicylic acid, 5-hydroxy-2-methacrylamido benzoic acid, 5-HMA, was incorporated with 2-hydroxyethyl methacrylate, (HEMA), in different proportions to the liquid phase of classical bone cement formulations. The monomer 5-HMA shows the ability to form molecular complexes with calcium atoms in order to improve osteointegration in the application of bone cement formulations used for the fixation of joint prostheses such as knee and hip. Kinetic parameters, peak temperature and setting time of the bone cement formulations prepared were determined, obtaining lower peak temperature values when 5-HMA was incorporated, with respect to classical acrylic bone cements based on PMMA. Mechanical and thermal properties as well as surface energy values, have been determined for all cured bone cement formulations.

Journal Article↗
PubMed1995

Is Salicylic Acid a Translocated Signal of Systemic Acquired Resistance in Tobacco?

Salicylic acid (SA) is a likely endogenous signal in the development of systemic acquired resistance (SAR) in some dicotyledonous plants. In tobacco mosaic virus (TMV)-resistant Xanthi-nc tobacco, SA levels increase systemically following the inoculation of a single leaf with TMV. To determine the extent to which systemic increases in SA result from SA export from the inoculated leaf, SA produced in TMV-inoculated or healthy leaves was noninvasively labeled with 18O2. Spatial and temporal distribution of 18O-SA indicated that most of the SA detected in the healthy tissues was synthesized in the inoculated leaf. No significant increase in the activity of benzoic acid 2-hydroxylase, the last enzyme involved in SA biosynthesis, was detected in upper uninoculated leaves, although the basal level of enzyme activity was relatively high. No increases in SA level, pathogenesis-related PR-1 gene expression, or TMV resistance in the upper uninoculated leaf were observed if the TMV-inoculated leaf was detached up to 60 hr after inoculation. Apart from the inoculated tissues, the highest increase in SA was observed in the leaf located directly above the inoculated leaf. The systemic SA increase observed during SAR may be explained by phloem transport of SA from the inoculation sites.

Journal Article↗
PubMed2005

Induction of an anionic peroxidase in cowpea leaves by exogenous salicylic acid.

Two isoperoxidases were detected in cowpea (Vigna unguiculata) leaves. Treatment of the primary leaves with 10mM salicylic acid increased the total peroxidase activity contributed by the anionic isoform. To isolate both the anionic and cationic peroxidases the leaf crude extract was loaded on a Superose 12 HR 10/30 column followed by chromatography on Mono-Q HR 5/5. Both enzymes were stable in a pH range from 5 to 7. The optimum-temperatures for the cationic and anionic peroxidase isoforms were, respectively, 20-30 degrees C and 30 degrees C. The dependence of guaiacol oxidation rate varying its concentration at constant H(2)O(2) concentration showed, for both enzymes, Michaelis-Menten-type kinetic. Apparent K(m)(s) were 0.8 and 4.8 microM for the cationic and anionic isoperoxidases, respectively.

Chromatography↗
PubMed2004

[Plant resistance inductors and active forms of oxygen. I. The influence of salicylic acid on hydrogen peroxide production in common cultures of wheat callus and bunt pathogen].

The influence of salicylic acid (SA) on cell resistance to bunt pathogen in wheat calluses has been studied. Cell staining by diaminobenzidin substratum (DAB-cells) was conditioned by hydrogen peroxide (H2O2) generation with the involvement of oxalate oxidase (OO). In the control group, DAB-staining was typical only of rhizoid cells (up to 50%). The infection caused no significant increase in the number of such cells; however, in the zone of fungus penetration parenchyma-like DAB-stained cells were observed (up to 24%). Under the influence of SA, the number of DAB-stained cells did not change, but increased in the zone of fungus penetration (up to 36%). Besides, SA increased OO activity and accelerated proembyogenic complex formation in the calluses, which, unlike rhizoids, were not sensitive to the phytopathogen. The infection caused an increase of OO activity in the cytoplasm and in an intercellular fraction, and an inhibition of an extracellular fraction of the enzyme.

3,3'-Diaminobenzidine↗
PubMed2005

Quantification of free and total salicylic acid in plants by solid-phase extraction and isocratic high-performance anion-exchange chromatography.

Salicylic acid (SA) is an important signaling compound in plants and is involved in various defense responses. Here we report a new method for quantification of free and total soluble SA in Arabidopsis thaliana with 5-fluorosalicylic acid (5-FSA) as internal standard. The SA was isolated from leaf extracts by solid-phase extraction with phenyl-phase cartridges and selectively eluted as the cationic iron(III)-complex. Recoveries of SA and 5-FSA were equal and exceeded 90%. Free SA was subsequently released from the iron(III)-complex by addition of 2,2'-bipyridyl and high-performance anion-exchange chromatography was performed on an NH2 column. The SA appeared as last peak with a retention time of 15 min, baseline-separated from other substances. On-line detection was performed fluorimetrically for both SA and 5-FSA at an excitation wavelength of 300 nm and an emission wavelength of 410 nm, because both substances give similar fluorescence spectra. The detection limit for SA was 5 ng g(-1) FW for a sample size of 100 mg. Thus the main advantages of the method are highly selective sample preparation, increased sensitivity, reduced analysis time compared with reversed-phase HPLC, and use of a novel internal standard detectable under the same conditions as SA. The techniques described are applicable to other plant materials.

Arabidopsis↗
PubMed2000

Degradable poly(anhydride ester) implants: effects of localized salicylic acid release on bone.

Degradable poly(anhydride ester) implants in which the polymer backbone breaks down into salicylic acid (SA) were investigated. In this preliminary work, local release of SA from the poly(anhydride esters), thus classified as 'active polymers', on healthy bone and tissue was evaluated in vivo using a mouse model. Degradable polyanhydrides that break down into inactive by-products were used as control membranes because of their chemical similarity to the active polymers. Small polymer squares were inserted over the exposed palatal bone adjacent to the maxillary first molars. Active polymer membranes were placed on one side of the mouth, control polymers placed on the contra lateral side. Intraoral clinical examination showed that active polymer sites were less swollen and inflamed than control polymer sites. Histopathological examination at day 1 showed essentially no difference between control and active polymers. After 4 days, active polymer sites showed epithelial proliferation to a greater extent than the polyanhydride controls. After 20 days, active polymer sites showed greater thickness of new palatal bone and no resorptive areas, while control polymer sites showed less bone thickness as well as resorption including lacunae involving cementum and dentine. From these preliminary studies, we conclude that active polymers, namely poly(anhydride esters), stimulated new bone formation.

Animals↗
PubMed1993

Accumulation of salicylic acid and indomethacin in isolated proximal tubular cells of the rat kidney.

The handling and accumulation of salicylic acid (SA) and indomethacin was examined in freshly isolated proximal tubular (PT) cells of the rat kidney in order to determine whether these cells provide a useful tool for studying accumulation of nonsteroidal anti-inflammatory drugs. A PT cell suspension was prepared by collagenase digestion, followed by filtration and isopycnic centrifugation. SA uptake was concentration-dependent and could be inhibited by probenecid. SA accumulated in the PT cells, and therefore, uptake is probably an active process. In the presence of probenecid, no SA accumulation was observed. Indomethacin uptake increased with time up to 2 min. Thereafter, a sharp decrease occurred, probably caused by inhibition of the oxidative phosphorylation. In the presence of probenecid, uptake was significantly reduced and no longer time-dependent. Indomethacin accumulated in the PT cells by a factor of more than 25. In the presence of probenecid, accumulation was decreased but was still considerable (approximately 10), probably as a result of binding to cellular protein. We conclude that as a result of carrier-mediated transport which is probenecid-sensitive, SA and indomethacin accumulate in the PT cells. The observed accumulation values are in accordance with previously observed values in the isolated perfused rat kidney. Therefore, freshly isolated PT cells appear to be a simple and useful model for studying the accumulation process of drugs like SA and indomethacin.

Animals↗
PubMed1997

Salicylic acid is a reducing substrate and not an effective inhibitor of ascorbate peroxidase.

This communication describes the interactions of salicylic acid (SA) with plant ascorbate peroxidase (APX). Contrary to a recent report (Durner, J., and Klessig, D. F. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 11312-11316) we show conclusively that ascorbate oxidation by APX is not inhibited by SA (10 mM), but that SA is a slow reducing substrate of this enzyme. The suggestion that SA-dependent inhibition of APX in planta may result in the elevation of H2O2 levels, which in turn acts as a second messenger in systemic acquired resistance signaling, is therefore not tenable. We conclude that APX remains a key antioxidant during systemic acquired resistance following pathogenic infection of plants. The transient products of SA oxidation by APX appear to be SA free radicals that undergo subsequent chemistry. APX-dependent oxidation of SA could be essential for diminishing the detrimental effects of this phenolic acid on plant cells.

Ascorbate Peroxidases↗