Francisco J. Corpas

Bio: Francisco J. Corpas is an academic researcher from Spanish National Research Council. The author has contributed to research in topics: Peroxisome & Nitric oxide. The author has an hindex of 74, co-authored 254 publications receiving 17491 citations. Previous affiliations of Francisco J. Corpas include University of Jaén & Arizona State University.

Cadmium-induced subcellular accumulation of O2·− and H2O2 in pea leaves

Abstract: Cadmium is a toxic metal that produces disturbances in plant antioxidant defences giving rise to oxidative stress. The effect of this metal on H2O2 and O2·− production was studied in leaves from pea plants growth for 2 weeks with 50 µm Cd, by histochemistry with diaminobenzidine (DAB) and nitroblue tetrazolium (NBT), respectively. The subcellular localization of these reactive oxygen species (ROS) was studied by cytochemistry with CeCl3 and Mn/DAB staining for H2O2 and O2·−, respectively, followed by electron microscopy observation. In leaves from pea plants grown with 50 µm CdCl2 a rise of six times in the H2O2 content took place in comparison with control plants, and the accumulation of H2O2 was observed mainly in the plasma membrane of transfer, mesophyll and epidermal cells, as well as in the tonoplast of bundle sheath cells. In mesophyll cells a small accumulation of H2O2 was observed in mitochondria and peroxisomes. Experiments with inhibitors suggested that the main source of H2O2 could be a NADPH oxidase. The subcellular localization of O2·− production was demonstrated in the tonoplast of bundle sheath cells, and plasma membrane from mesophyll cells. The Cd-induced production of the ROS, H2O2 and O2·−, could be attributed to the phytotoxic effect of Cd, but lower levels of ROS could function as signal molecules in the induction of defence genes against Cd toxicity. Treatment of leaves from Cd-grown plants with different effectors and inhibitors showed that ROS production was regulated by different processes involving protein phosphatases, Ca2+ channels, and cGMP.

Reactive Oxygen Species and Reactive Nitrogen Species in Peroxisomes. Production, Scavenging, and Role in Cell Signaling

Abstract: Peroxisomes can be broadly defined as subcellular organelles bounded by a single membrane that contain as basic enzymatic constituents catalase and hydrogen peroxide (H2O2)-producing flavin oxidases and occur in almost all eukaryotic cells ([Baker and Graham, 2002][1]). In recent years, it has

Cadmium effect on oxidative metabolism of pea (Pisum sativum L.) roots. Imaging of reactive oxygen species and nitric oxide accumulation in vivo

Abstract: Growth of pea (Pisum sativum L.) plants with 50 microM CdCl2 for 15 d produced a reduction in the number and length of lateral roots, and changes in structure of the principal roots affecting the xylem vessels. Cadmium induced a reduction in glutathione (GSH) and ascorbate (ASC) contents, and catalase (CAT), GSH reductase (GR) and guaiacol peroxidase (GPX) activities. CuZn-superoxide dismutase (SOD) activity was also diminished by the Cd treatment, although Mn-SOD was slightly increased. CAT and CuZn-SOD were down-regulated at transcriptional level, while Mn-SOD, Fe-SOD and GR were up-regulated. Analysis of reactive oxygen species (ROS) and nitric oxide (NO) levels by fluorescence and confocal laser microscopy (CLM) showed an over-accumulation of O2*- and H2O2, and a reduction in the NO content in lateral and principal roots. ROS overproduction was dependent on changes in intracellular Ca+2 content, and peroxidases and NADPH oxidases were involved. Cadmium also produced an increase in salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) contents. The rise of ET and ROS, and the NO decrease are in accordance with senescence processes induced by Cd, and the increase of JA and SA could regulate the cellular response to cope with damages imposed by cadmium.

Reactive Oxygen Species, Oxidative Damage, and Antioxidative Defense Mechanism in Plants under Stressful Conditions

Abstract: Reactive oxygen species (ROS) are produced as a normal product of plant cellular metabolism. Various environmental stresses lead to excessive production of ROS causing progressive oxidative damage and ultimately cell death. Despite their destructive activity, they are well-described second messengers in a variety of cellular processes, including conferment of tolerance to various environmental stresses. Whether ROS would serve as signaling molecules or could cause oxidative damage to the tissues depends on the delicate equilibrium between ROS production, and their scavenging. Efficient scavenging of ROS produced during various environmental stresses requires the action of several nonenzymatic as well as enzymatic antioxidants present in the tissues. In this paper, we describe the generation, sites of production and role of ROS as messenger molecules as well as inducers of oxidative damage. Further, the antioxidative defense mechanisms operating in the cells for scavenging of ROS overproduced under various stressful conditions of the environment have been discussed in detail.

Free radicals, antioxidants and functional foods: Impact on human health

Abstract: In recent years, there has been a great deal of attention toward the field of free radical chemistry. Free radicals reactive oxygen species and reactive nitrogen species are generated by our body by various endogenous systems, exposure to different physiochemical conditions or pathological states. A balance between free radicals and antioxidants is necessary for proper physiological function. If free radicals overwhelm the body's ability to regulate them, a condition known as oxidative stress ensues. Free radicals thus adversely alter lipids, proteins, and DNA and trigger a number of human diseases. Hence application of external source of antioxidants can assist in coping this oxidative stress. Synthetic antioxidants such as butylated hydroxytoluene and butylated hydroxyanisole have recently been reported to be dangerous for human health. Thus, the search for effective, nontoxic natural compounds with antioxidative activity has been intensified in recent years. The present review provides a brief overview on oxidative stress mediated cellular damages and role of dietary antioxidants as functional foods in the management of human diseases.