Search results for "OXIDASE"

Arthropod-induced neoplastic formations on trees change photosynthetic pigment levels and oxidative enzyme activities

2005

Abstract In order to test the hypothesis that arthropod-induced neoplastic formations on trees affect biochemical characteristics of both the newly formed galls and host plant tissues, biochemical characteristics with a possible adaptive role were determined in nine gall-former–host tree combinations. Photosynthetic pigments, extractable protein content, and oxidative enzyme activities were determined in gall tissues, leaf tissues of galled leaves, and leaves on ungalled tree branches. Neoplastic tissues were characterized by a low content of photosynthetic pigments, decreased chlorophyll a/b ratio, lower extractable protein content, and decreased activities of peroxidase and polyphenol oxi…

Effect of titanium (IV) application on some enzymatic activities in several developing stages of red pepper plants

1994

Abstract The effect of two titanium (IV) compounds, titanium ascorbate and titanium chloride, on some enzymatic activities, such as catalase, peroxidase, lipoxygenase and nitrate reductase in seeds, embryos, and seedlings and adult plants of red pepper (Capsicum annuum L.), was studied. A stimulatory effect of titanium was observed for every iron‐depending enzyme studied at all developing stages as well as for nitrate reductase but only for whole plants. This occurs because Ti+3/Ti+4 catalizes the activity of iron and enhances iron‐dependent enzymes.

Wound-induced responses in leaves of strawberry cultivars differing in susceptibility to spider mite

2002

Summary The effect of leaf detachment and wounding on the activities of oxidative enzymes and ethylene production was studied in strawberry (Fragaria × ananassa) cultivars, differing in susceptibility to the spider mite (Tetranychus urticae Koch.). Strawberry plants were cultivated during winter in two growth conditions - with and without overwintering, in greenhouse and laboratory, respectively. Polyphenol oxidase activity, peroxidase activity and catalase activity in strawberry leaves depended on the cultivar analysed, type of treatment (detachment or detachment and wounding), as well as on plant growth conditions. Activities of all analysed enzymes were higher in control plants grown in …

Changes of morphogenic competence in mature Pinus sylvestris L. buds in vitro.

2002

The effects of season and cold storage on morphogenic competence in mature Pinus sylvestris buds were investigated. Peroxidase and polyphenol oxidase activity were measured as markers of oxidative metabolism. No growth in vitro was observed on explants detached from the end of January until the beginning of March. Brachioblasts, each with a couple of needles, formed on 11 % of the buds without macrostrobili that were detached in early April and introduced immediately into culture. Of the explants detached in late July, 15 % formed shoots with brachioblasts and needles. The lowest activity of peroxidase and polyphenol oxidase in pine buds was observed from the end of April until the beginnin…

Pattern of polyamines and related monoacetyl derivatives in chick embryo retina during development.

1994

Polyamines and related monoacetyl derivatives were studied in chick embryo retina during development (6th-19th day). Putrescine, which is high in the first phase of retinogenesis, is necessary to sustain both tissue proliferation and via N-acetylputrescine, gamma-aminobutyric acid synthesis. A later increase in spermidine and particularly spermine may play a role in the last phase of development when the retina reaches maturation. The presence of N1-acetylspermidine already at the 8th day indicates that in chick embryo retina, putrescine synthesis can depend on two separate pathways. The first involves ornithine decarboxylase activity; the second, spermidine/spermine N1-acetyltransferase an…

Cytochrome oxidase activity in the mitochondria of unfertilized and fertilized sea urchin eggs

1959

Abstract The cytochrome oxidase activity of isolated mitochondria of unfertilized and fertilized eggs of Paracentrotus lividus has been studied. It has been found that whereas in the mitochondria of unfertilized eggs saturation is reached at a cytochrome c concentration of 3.28 × 10−5 M, in those of fertilized eggs this occurs at a concentration of 5.74 × 10−5 M. It is shown that upon fertilization an increase of about 30 per cent of the activity of cytochrome oxidase takes place and no further changes appear to occur until blastula stage.

Selenium: A Cure for Autoimmune Thyroiditis.

2021

Autoimmune thyroiditis (AT) is a disease whose incidence has increased dramatically over the past few decades. In iodine sufficient areas, this pathological condition affects up to 5% of the general population. The higher incidence of AT observed in areas of the world with low-selenium (Se) soils apperas to be the consequence of a reduced activity of the intracellular Sedependent glutathione peroxidase activity. Se is involved, through selenoproteins, in the regulation of intracellular antioxidant, redox and anti-inflammatory processes. As a component of selenoproteins, Se exerts various structural and enzymatic functions. A low Se/high fat diet can cause selenoprotein changes and promote t…

Glutathione Peroxidase Activity and Selenium Therapy in Muscular Dystrophies

1988

Photochemical holes under pressure: Compressibility and volume fluctuations of a protein

1991

From the pressure induced frequency shift of photochemical holes burnt into mesomorphyrin substituted horseradish peroxidase, we determined the compressibility of the protein and the vacuum frequency of the chromophore. From the compressibility, an estimation of the volume fluctuations of the biomolecule is possible.

4-hydroxynonenal inhibits glutathione peroxidase: protection by glutathione

1999

Abstract 4-Hydroxy-2,3-trans-nonenal, a lipid peroxidation product, inhibits glutathione peroxidase in a concentration-dependent manner. The concentration providing 50% inhibition is 0.12 mM. This inhibition can be almost completely (89%) prevented by 1 mM glutathione added to the incubation mixture 30 min before 4-hydroxy-2,3-trans-nonenal or 2,3-trans-nonenal, but not by other thiol-containing antioxidants such as 0.5 mM dithiothreitol or β-mercaptoethanol. Again the addition of 1 mM glutathione, and not of 0.5 mM dithiothreitol or β-mercaptoethanol, to the enzyme 30 min after incubation with 4-hydroxy-2,3-trans-nonenal restores activity to the same extent as does the preincubation with G…