INTRODUCTION A major activity at glutamatergic synapses in the brain is the production of potentially toxic oxygen radicals, in particular superoxide, by postsynaptic enzymes such as PGH synthase and by mitochondria. These need antioxidant mechanisms, such as the local production of antioxidant molecules (such as glutathione and ascorbate) and antioxidant enzymes, for protection of the neuron a...

One-year-old grapevines (Vitis labrusca L. cv. Concord) were supplied with 0, 5, 10, 15, or 20 mM nitrogen (N) in a modified Hoagland's solution twice weekly for 4 weeks. As leaf N decreased in response to N limitation, leaf chlorophyll (Chl) decreased linearly whereas leaf absorptance declined curvilinearly. Compared with high N leaves, low N leaves had lower quantum efficiency of PSII as a re...

Understanding how the fruit microclimate affects ascorbate (AsA) biosynthesis, oxidation and recycling is a great challenge in improving fruit nutritional quality. For this purpose, tomatoes at breaker stage were harvested and placed in controlled environment conditions at different temperatures (12, 17, 23, 27 and 31 °C) and irradiance regimes (darkness or 150 µmol m(-2) s(-1)). Fruit pericarp...

Praseodymium enhanced the tolerance of maize seedlings subjected to cadmium stress by up-regulating enzymes in regeneration and biosynthetic pathways ascorbate glutathione | Qidi Zhu, Yanyan Li, Shang Gao, Changjuan Shan Agricultural Journals

Changing glutathione levels have often been implicated in mitotic events since Rapkine discovered the cyclic variation of a trichloroacetic acid (TCA)-soluble sulfhydryl (SH)-containing molecule in synchronously dividing sea urchin embryos (1) . However, Waley has pointed out that many studies of glutathione fail to use assays of sufficient specificity, in that small peptides, ascorbate, and cy...

5-Aminolevulinic acid (ALA) is the precursor of tetrapyrrole synthesis, and hydrogen sulfide (H2S) a gas signal molecule. Studies have shown that exogenous ALA H2S can alleviate abiotic stress. This study evaluated roles their interactions in regulating antioxidant activity pepper seedlings under chilling Chilling stress significantly inhibited growth increased amounts peroxide (H2O2), superoxi...

Levels of reactive oxygen species (ROS) are tightly regulated in mammalian cells. A variety of enzymes produce ROS, including NAD(P)H oxidase, xanthine oxidase, glucose oxidase, myeloperoxidase, the family of nitric oxide synthases, and mitochondrial enzymes.1–4 Low levels of ROS such as superoxide or hydrogen peroxide regulate highly specific targets.5,6 In the cardiovascular system, for examp...

Protein thiyl radicals are important intermediates generated in redox processes of thiols and disulfides. Thiyl radicals efficiently react with glutathione and ascorbate, and the common notion is that these reactions serve to eliminate thiyl radicals before they can enter potentially hazardous processes. However, over the past years increasing evidence has been provided for rather efficient int...

In this study, we characterized the role of an apple cytosolic malate dehydrogenase gene (MdcyMDH) in the tolerance to salt and cold stresses and investigated its regulation mechanism in stress tolerance. The MdcyMDH transcript was induced by mild cold and salt treatments, and MdcyMDH-overexpressing apple plants possessed improved cold and salt tolerance compared to wild-type (WT) plants. A dig...

2.1. Glutathione 2.1.A. Biological Functions 2.1.B. Biosynthesis 2.1.C. Degradation 2.1.D. Other Thiol-Based Redox Buffers 2.2. Ascorbate 2.2.A. Ascorbate Chemistry 2.2.B. Ascorbate Biosynthesis 2.2.C. Ascorbate Recycling 2.2.D. Ascorbate Transport 2.2.E. Importance of Ascorbate in Stress and Disease 2.3. Other Antioxidants 2.3.A. Lipid-Soluble Antioxidants 2.3.B. Water-Soluble Antioxidants 2.3...