Syringaldazine Peroxidase Activity Research Articles

Arabidopsis plants exposed to gamma radiation in two successive generations show a different oxidative stress response

When terrestrial environments get contaminated with long-lived gamma emitting radionuclides, plants that grow in these contaminated areas are exposed to gamma radiation during consecutive generations. Therefore it is important to evaluate the gamma induced stress response in plants in and between generations. The objective of this research is to reveal differences at the level of the antioxidative stress response between generations with a different radiation history. An experiment was conducted in which 7-days old Arabidopsis thaliana plants were exposed for 14 days to four different gamma dose rates: 22 mGy/h, 38 mGy/h, 86 mGy/h and 457 mGy/h. Two different plant groups were used: plants that were not exposed to gamma radiation before (P0) and plants that received the aforementioned gamma treatment during their previous generation (S1). Growth, the concentration of the antioxidants ascorbate and glutathione, a number of antioxidative enzyme activities and their gene transcript levels were analysed. A dose-rate dependent induction was seen for catalase (CAT) and guaiacol peroxidase (GPX) in the roots and for syringaldazine peroxidase (SPX) in the shoots. Differences between the two generations were observed for CAT and GPX in the roots, where a significantly higher activity of these reactive oxygen species (ROS) detoxifying enzymes was observed in the S1 generation. For SPX in the shoots, a dose dependent upregulation was observed in the P0 generation. However, high SPX activities were present for all doses in the S1 generation. These differences in enzyme activity between generations for SPX and GPX and the involvement of these enzymes in cell wall biosynthesis, suggest an important role for cell wall strengthening in the response to gamma irradiation.

Syringaldazine peroxidase stimulates lignification by enhancing polyamine catabolism in wheat during heat and drought stress

Six wheat cultivars, namely PBW 343, PBW 550 (stress susceptible), PBW 621, PBW 175 (drought tolerant), C 306 and HD 2967 (heat tolerant), were used in this study to evaluate the effect of heat and drought stress on the activities of peroxidases (POXs), diamine oxidase (DAO), polyamine oxidase (PAO) and arginine decarboxylase (ADC) and ornithine decarboxylase (ODC) in relation to contents of polyamines (PAs), lipid peroxide and lignin. High temperature (HT) elevated activities of syringaldazine peroxidase (SPX), guaiacol peroxidase (GPX) and coniferyl alcohol peroxidase (CPX) in heat tolerant cultivars while, drought stress accentuated ADC/ODC activities in drought tolerant cultivars. Both heat and drought stress enhanced activities of DAO and PAO alongwith contents of H2O2 in PBW 175 and C 306. Amongst studied POXs, SPX activity was relatively more and coincided well with lignin content under HT stress while, the levels of ADC/ODC paralleled with putrescine and spermidine contents under drought stress. Higher build up of thiobarbituric acid reactive substances in cultivars PBW 343 and PBW 550 indicated their membrane instability during both the stresses. Our results revealed that SPX mediated lignification leading to higher cell wall rigidity under heat stress and drought increased PAs involved in ROS scavenging due to presence of positive charges which can bind strongly to the negative charges in cellular components such as proteins and phospholipids and thereby stabilize the membranes under stress conditions.

Protective effect of ascorbic acid and glutathione on AlCl<sub>3</sub>-inhibited growth of rice roots

The effect of AlCl3 on the antioxidant system of rice roots and the role of applied antioxidants ascorbic acid (AsA) and glutathione (GSH) in AlCl3-inhibited growth of rice roots were investigated. AlCl3 treatment resulted in a rapid inhibition of root growth but had no effect on lipid peroxidation and antioxidative enzyme activities in rice roots. AlCl3 treatment resulted in lower content of H2O2, AsA, and GSH than in controls. Exogenous AsA or GSH counteracted growth inhibition of rice roots induced by AlCl3. AlCl3 treatment increased syringaldazine peroxidase (SPOX) activities and lignin content in rice roots. Exogenous AsA or GSH prevented the decrease in H2O2 content and the increase in SPOX activities and lignin content in rice roots caused by AlCl3. Results suggest that lignification induced by low AsA or GSH content may explain the mechanism of Al-inhibited growth of rice roots.

Changes in antioxidant and lignifying enzyme activities in sunflower roots ( Helianthus annuus L.) stressed with copper excess

Treatment with 50 μM CuSO 4 for five days caused significant decrease in dry-matter production and protein level of ten-day-old sunflower seedling roots. An increase of lipoperoxidation product rate was also observed. The involvement of some enzyme activities in the sunflower root defence against Cu-induced oxidative stress was studied. Copper treatment induced several changes in antioxidant enzymes. SOD (superoxide dismutase, EC 1.15.1.1) activity was reduced but CAT (catalase, EC 1.11.1.6) and GPX (guaiacol peroxidase, EC 1.11.1.7) activities were significantly enhanced. The lignifying peroxidase activities, assayed using coniferyl alcohol and syringaldazine, were also stimulated. Analysis by native gel electrophoresis of syringaldazine peroxidase activity showed the stimulation of an isoform (A2) and the induction of another one (A1) under cupric stress conditions. On the other hand, the activity of PAL (phenylalanine ammonia lyase, EC 4.3.1.5), which plays an important role in plant defence, was also activated. The possible mechanisms by which Cu-induced growth delay and changes in enzymatic activities involved in plant defence processes are discussed. To cite this article: H. Jouili, E. El Ferjani, C. R. Biologies 326 (2003).

Effect of NAA on the development, apoplastic peroxidase activities, and peroxidase isoenzymes in chicory root explants

Summary NAA significantly modified the growth of chicory (Cichorium intybus L. cv. Bea) root explants cultured for 12 d in either light or darkness. It also reduced the chlorophyll and the lignin content, peroxidase (EC 1.11.1.7) activities such as guaiacol peroxidase, auxin oxidase, and syringaldazine peroxidase in light as well as in darkness. There was a positive relationship between specific syringaldazine peroxidase activity and the lignin content, as well as between anionic peroxidases and lignification. Conversely, specific IAA oxidase activity and fresh weight were negatively correlated. NAA enhanced the expression of cationic peroxidase isoenzymes, particularly a peroxidase isoform pI 8.9 (Cicpx), in darkness and in light. This Cicpx was not involved in the lignification process. NAA is suggested as exerting an inhibitory effect on the biosynthetic pathways of tetrapyrrole-containing compounds.

Changes in soluble and cell wall-bound peroxidase activities with growth in anoxia-treated rice ( Oryza sativa L.) coleoptiles and roots

The activity of soluble and cell wall-bound (1.0 M NaCl extractable) peroxidase in relation to growth of anoxia-grown Indica rice seedlings ( Oryza sativa L. cv. Taichung Native 1) was examined. Guaiacol and syringaldazine were used to assay for peroxidase activity. In air-grown coleoptiles, guaiacol or syringaldazine peroxidase activity initially decreased or remained constant, respectively, in the early period but then both increased as coleoptile elongation ceased. In air-grown roots, both guaiacol and syringaldazine peroxidase activities decreased slightly during the growth period. In response to anoxia, coleoptile elongation was stimulated but root growth was seriously inhibited. Anoxia induced a significant decrease in activity of cell wall-bound guaiacol and syringaldazine peroxidase while soluble peroxidase activity was not affected in coleoptiles. In contrast to coleptiles, anoxia-grown roots showed an increase in cell wall-bound guaiacol and syringaldazine peroxidase activities. When transferred to aerobic conditions, cell wall-bound guaiacol and syringaldazine peroxidase activities in anoxia-grown coleoptiles and roots recovered almost to the air-control levels. On exposure to ABA, the enhancement of coleoptile elongation and the decrease of cell wall-bound peroxidase activity in anoxia-grown coleoptiles were inhibited. These results indicate that there is a reciprocal correlation between growth and cell wall-bound peroxidase levels in etiolated rice seedlings.

Effects of manganese deficiency on soluble apoplastic peroxidase activities and lignin content in needles of Norway spruce (Picea abies).

Apoplastic peroxidase activities were investigated in manganese-deficient and manganese-sufficient needles of field-grown Norway spruce trees (Picea abies L.). In Mn-sufficient needles, two sets of peroxidases, one with an alkaline pI >/= 9 and another with an acidic pI </= 3, were identified using guaiacol or coniferylalcohol as substrates for activity staining after isoelectric focusing in a pH gradient from 3 to 9. The acidic peroxidases were capable of Mn-dependent NADH oxidation and H(2)O(2) formation. Syringaldazine peroxidase activity was not found in apoplastic extracts, but was present in whole-needle extracts. Manganese deficiency did not affect the activity or the isoelectric focusing pattern (pH 3 to 9) of the apoplastic peroxidases. Soluble peroxidase activities from whole-needle extracts were significantly higher in Mn-deficient than in Mn-sufficient needles with all substrates tested. Mn-deficient needles contained slightly less cell wall material than Mn-sufficient needles, but the lignin content was similar. Neither apoplastic peroxidase activity nor lignification was affected by Mn deficiency, suggesting that apoplastic peroxidases are regulated independently from symplastic peroxidases.

A comparative biochemical and cytological characterization of normal and habituated sugarbeet calli

Habituated sugarbeet callus examined by means of a light-microscope is characterized by absence of differentiated tracheary elements and of the reaction with syringaldazine. Habituated tissues also were found to exhibit low guaiacol- and syringaldazine-peroxidase activities, a deficiency of lignin as well as lower cellulose, dry mass and chlorophyll contents as compared to the normal auxin-requiring callus. These histological and cytological features led to consider this habituated callus as a vitrified tissue under stress. The question of a relationship between vitrification and habituation is posed.

Balance between anionic and cationic extracellular peroxidase activities in Sedum album leaves after ozone exposure. Analysis by high‐performance liquid chromatography

Peroxidase activity was assayed with different electron donors (guaiacol, ascorbate, syringaldazine) in the intercellular fluid of Sedum album L. leaves after ozone exposure. Anionic and cationic peroxidases were separated and purified by high performance ion‐exchange and gel permeation chromatography. Both isoperoxidases were tested as regards their molecular weight and apparent kinetic constants with different substrates. Ascorbate peroxidase activity was rapidly stimulated after ozone exposure, whereas syringaldazine peroxidase activity reached its maximum 24 h later. Increases in ascorbate and syringaldazine peroxidase activities occurred simultaneously with increases in cationic and anionic peroxidase activities, respectively. Apparent Km values indicate a high affinity of cationic peroxidases for ascorbate and of anionic peroxidases for syringaldazine. The metabolic role of this balance between cationic and anionic peroxidases after ozone exposure is discussed.