ABSTRACT
Melatonin is a signaling molecule that mediates multiple stress-dependent reactions. Under photooxidative stress conditions generating intensive ROS production, exogenous melatonin (50 µM) contributed to maintaining the expression of mitochondrial encoded genes and up-regulation of RNA-polymerase genes RPOTm and RPOTmp, operating through the CAND2 receptor and α-subunit of the heterotrimeric G protein GPA1 coupled with CAND2. Unlike wild-type plants, mutants with defective CAND2 and GPA1 genes exhibited no decrease in the alternative pathway of leaf respiration, as well as the activity of an alternative oxidase, and the expression of the AOX1a gene. At the same time, the protective effect of exogenous melatonin on some physiological indicators did not depend on the receptor and was associated with the direct antioxidant function of the regulator. Thus, melatonin under photooxidative stress conditions can act as an antioxidant and as a hormone capable of regulating the expression of nuclear and organelle genes through the components of melatonin signal perception.
Subject(s)
Arabidopsis Proteins , Gene Expression Regulation, Plant , Genes, Mitochondrial , Melatonin , Receptors, G-Protein-Coupled , Arabidopsis , Arabidopsis Proteins/genetics , Gene Expression , Melatonin/metabolism , Melatonin/pharmacology , Receptors, G-Protein-Coupled/genetics , Receptors, Melatonin/metabolismABSTRACT
The effect of melatonin on respiration and production (release) of hydrogen peroxide during succinate oxidation in mitochondria isolated from lupine cotyledons and epicotyls of pea seedlings was studied. It was shown for the first time that melatonin (10-7-10-3 M) had a significant inhibitory effect on the production of peroxide by plant mitochondria, which was characterized by concentration dependence and species specificity. At the same time, melatonin (at a concentration of up to 100 µM) had virtually no effect on mitochondrial respiration rate and respiratory control coefficient. The results confirm the antioxidant function of melatonin and indicate that it is involved in the regulation of ROS levels and maintenance of redox balance in plant mitochondria.
Subject(s)
Lupinus/cytology , Melatonin/pharmacology , Mitochondria/drug effects , Mitochondria/metabolism , Peroxides/metabolism , Pisum sativum/cytology , Dose-Response Relationship, Drug , Lupinus/drug effects , Pisum sativum/drug effects , Succinic Acid/metabolismSubject(s)
Mitochondria/physiology , Mitochondria/ultrastructure , Pisum sativum/physiology , Pisum sativum/ultrastructure , Seedlings/physiology , Seedlings/ultrastructure , Stress, Physiological/physiology , Cold Temperature , Mitochondria/drug effects , Pisum sativum/drug effects , Phosphinic Acids/pharmacology , Plant Growth Regulators/pharmacology , Seedlings/drug effects , Stress, Physiological/drug effects , Triazines/pharmacology , Water/metabolismABSTRACT
Experimental data on the mitochondrial ultrastructure and tissue respiration in root apex as well as metabolic activity of the organelles isolated from pea seedling roots after 5-day of clinorotation are presented. It was shown that mitochondrial condensation in the distal elongation zone correlated with an increased rate of oxygen uptake on 7%. We also observed increase in rate of malate oxidation and respiratory control ratio increased simultaneously with a decreased in efficiency of oxidative phosphorylation. Such character of mitochondrial rearrangements in simulated microgravity is assumed to be a consequence of adaptation to these conditions.
Subject(s)
Mitochondria/metabolism , Pisum sativum/metabolism , Plant Cells/metabolism , Plant Roots/metabolism , Seedlings/metabolism , Adenosine Triphosphate/biosynthesis , Cell Respiration/physiology , Malates/metabolism , Microscopy, Electron , Mitochondria/ultrastructure , Oxidative Phosphorylation , Pisum sativum/ultrastructure , Plant Roots/ultrastructure , Polarography , Rotation , Seedlings/ultrastructure , Weightlessness SimulationSubject(s)
Electron Transport Chain Complex Proteins/metabolism , Gene Expression Regulation, Plant/physiology , Genes, Mitochondrial/physiology , Lupinus/genetics , Salicylic Acid/metabolism , Transcription, Genetic/physiology , Cotyledon/drug effects , Cotyledon/metabolism , Electron Transport Chain Complex Proteins/drug effects , Electron Transport Chain Complex Proteins/genetics , Gene Expression Regulation, Plant/drug effects , Genes, Mitochondrial/drug effects , Lupinus/metabolism , Mitochondria/drug effects , Mitochondria/metabolism , Plant Growth Regulators/chemistry , Plant Growth Regulators/metabolism , Salicylic Acid/chemistry , Salicylic Acid/pharmacology , Transcription, Genetic/drug effectsSubject(s)
Cold Temperature , Droughts , Fatty Acids/metabolism , Lipid Peroxidation/physiology , Mitochondrial Membranes/metabolism , Pisum sativum/metabolism , Seedlings/metabolism , Fatty Acids/analysis , Lipid Peroxidation/drug effects , Mitochondrial Membranes/chemistry , Mitochondrial Membranes/drug effects , Pisum sativum/growth & development , Phosphinic Acids/pharmacology , Seedlings/drug effects , Triazines/pharmacologySubject(s)
Lipid Peroxidation/drug effects , Mitochondria/metabolism , Phosphinic Acids/pharmacology , Pisum sativum/metabolism , Plant Growth Regulators/pharmacology , Pyrimidines/pharmacology , Seeds/metabolism , Triazines/pharmacology , Water/metabolism , Droughts , Germination/drug effects , Mitochondria/drug effects , Plant Extracts/metabolism , Seedlings/drug effects , Seedlings/growth & development , Seeds/drug effectsSubject(s)
Fatty Acids/metabolism , Phosphinic Acids/pharmacology , Pisum sativum/drug effects , Pisum sativum/metabolism , Triazines/pharmacology , Droughts , Fatty Acids/analysis , Fatty Acids/chemistry , Fatty Acids, Unsaturated/analysis , Fatty Acids, Unsaturated/chemistry , Fatty Acids, Unsaturated/metabolism , Membrane Lipids/metabolism , Mitochondrial Membranes/drug effects , Mitochondrial Membranes/metabolism , Pisum sativum/growth & development , Plant Growth Regulators/pharmacology , Seedlings/drug effects , Seedlings/metabolism , Stress, PhysiologicalSubject(s)
Organophosphonates/pharmacology , Phosphinic Acids/pharmacology , Plants/drug effects , Triazines/pharmacology , Animals , Catalysis , Cold Temperature , Electrons , Kinetics , Mitochondria, Liver/drug effects , Mitochondria, Liver/metabolism , Organophosphonates/chemistry , Plant Growth Regulators/metabolism , Plant Roots/drug effects , Plant Roots/metabolism , Rats , Seeds/metabolism , Water/metabolismSubject(s)
Cell Membrane/drug effects , Mitochondria, Liver/drug effects , Mitochondria/drug effects , Phosphinic Acids/pharmacology , Triazines/pharmacology , Animals , Beta vulgaris/cytology , Beta vulgaris/drug effects , Electron Transport/drug effects , Energy Metabolism/drug effects , Microsomes, Liver/drug effects , Plant Roots/cytology , Plant Roots/drug effects , RatsSubject(s)
Cell Membrane/metabolism , Phosphinic Acids/pharmacology , Plant Roots/drug effects , Triazines/pharmacology , Animals , Beta vulgaris/drug effects , Erythrocyte Membrane/drug effects , Mice , Mice, Inbred Strains , Microsomes, Liver/drug effects , Mitochondria, Liver/drug effects , Mitochondrial Membranes/metabolism , Rats , Rats, Inbred StrainsABSTRACT
Incubation of cells of the cyanobacterium Spirulina platensis under conditions of exposure to low-intensity (2-3 microE m-2 s-1) red light, which was predominantly absorbed by photosystem I (PS I), caused atypical adaptation changes. Invariable pigment composition and stoichiometry of photosystems was observed in the cells incubated under these conditions against the background of a decrease in the rate of photosynthetic fixation of CO2 (by one-half) and a 1.5-fold increase in the rate of dark respiration relative to cells incubated under conditions of exposure to green light. Comparison of these data with a high rate of dark relaxation of P700+ in the presence of diuron suggests that deficiency of reduced equivalents at the donor side of PS I in the Spirulina cells exposed to red light is compensated by electron supply from the respiratory chain NAD(P)H dehydrogenase complex.