ABSTRACT
The role of NADPH oxidases under cadmium (Cd) toxicity was studied using Arabidopsis thaliana mutants AtrbohC, AtrbohD and AtrbohF, which were grown under hydroponic conditions with 25 and 100 µM Cd for 1 and 5 days. Cadmium reduced the growth of leaves in WT, AtrbohC and D, but not in AtrbohF. A time-dependent increase in H2 O2 and lipid peroxidation was observed in all genotypes, with AtrbohC showing the smallest increase. An opposite behaviour was observed with NO accumulation. Cadmium increased catalase activity in WT plants and decreased it in Atrboh mutants, while glutathione reductase and glycolate oxidase activities increased in Atrboh mutants, and superoxide dismutases were down-regulated in AtrbohC. The GSH/GSSG and ASA/DHA couples were also affected by the treatment, principally in AtrbohC and AtrbohF, respectively. Cadmium translocation to the leaves was severely reduced in Atrboh mutants after 1 day of treatment and even after 5 days in AtrbohF. Similar results were observed for S, P, Ca, Zn and Fe accumulation, while an opposite trend was observed for K accumulation, except in AtrbohF. Thus, under Cd stress, RBOHs differentially regulate ROS metabolism, redox homeostasis and nutrient balance and could be of potential interest in biotechnology for the phytoremediation of polluted soils.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/enzymology , Cadmium/toxicity , NADPH Oxidases/metabolism , Reactive Oxygen Species/metabolism , Antioxidants/metabolism , Arabidopsis/drug effects , Arabidopsis/growth & development , Arabidopsis/radiation effects , Ascorbic Acid/metabolism , Catalase/metabolism , Cell Respiration/drug effects , Cell Respiration/radiation effects , Glutathione/metabolism , Glutathione Reductase/metabolism , Hydrogen Peroxide/metabolism , Light , Lipid Peroxidation/drug effects , Lipid Peroxidation/radiation effects , Minerals/metabolism , Mutation/genetics , Nitric Oxide/metabolism , Plant Leaves/drug effects , Plant Leaves/metabolism , Plant Leaves/radiation effects , Principal Component Analysis , Stress, Physiological/drug effects , Stress, Physiological/radiation effects , Superoxide Dismutase/metabolismABSTRACT
Thirty five patients with acute Chagas' disease who demonstrated parasitaemia at the time of the investigation were submitted to a detailed electromyographical study. With their muscles at rest, 12 patients showed fibrillation potentials and/or positive sharp waves. On volitional contraction, 7 had short duration motor unit potentials (MUPs) and low polyphasic MUPs. On motor and sensory nerve fibers conduction studies, 20 disclosed values below the lower control limit within one or more nerves. Finally, 12 patients produced a muscle decremental response on nerve supramaximal repetitive stimulation. The findings signal that primary muscle involvement, neuropathy and impairement of the neuromuscular transmission, either isolated or combined, may be found in the acute stage of human Chagas' disease.
