title: Cross talk among calcium, hydrogen peroxide, and nitric oxide and activation of gene expression involving calmodulins and calcium-dependent protein kinases in Ulva compressa exposed to copper excess.
abstract: To analyze the copper-induced cross talk among calcium, nitric oxide (NO), and hydrogen peroxide (H(2)O(2)) and the calcium-dependent activation of gene expression, the marine alga Ulva compressa was treated with the inhibitors of calcium channels, ned-19, ryanodine, and xestospongin C, of chloroplasts and mitochondrial electron transport chains, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and antimycin A, of pyruvate dehydrogenase, moniliformin, of calmodulins, N-(6-aminohexyl)-5-chloro-1-naphtalene sulfonamide, and of calcium-dependent protein kinases, staurosporine, as well as with the scavengers of NO, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, and of H(2)O(2), ascorbate, and exposed to a sublethal concentration of copper (10 μm) for 24 h. The level of NO increased at 2 and 12 h. The first peak was inhibited by ned-19 and 3-(2,3-dichlorophenyl)-1,1-dimethylurea and the second peak by ned-19 and antimycin A, indicating that NO synthesis is dependent on calcium release and occurs in organelles. The level of H(2)O(2) increased at 2, 3, and 12 h and was inhibited by ned-19, ryanodine, xestospongin C, and moniliformin, indicating that H(2)O(2) accumulation is dependent on calcium release and Krebs cycle activity. In addition, pyruvate dehydrogenase, 2-oxoxglutarate dehydrogenase, and isocitrate dehydrogenase activities of the Krebs cycle increased at 2, 3, 12, and/or 14 h, and these increases were inhibited in vitro by EGTA, a calcium chelating agent. Calcium release at 2, 3, and 12 h was inhibited by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and ascorbate, indicating activation by NO and H(2)O(2). In addition, the level of antioxidant protein gene transcripts decreased with N-(6-aminohexyl)-5-chloro-1-naphtalene sulfonamide and staurosporine. Thus, there is a copper-induced cross talk among calcium, H(2)O(2), and NO and a calcium-dependent activation of gene expression involving calmodulins and calcium-dependent protein kinases.
authors.affiliation: Departamento de Biología, Universidad de Santiago de Chile, 9170022 Santiago, Chile.
authors.forename: Alberto
authors.initials: A
authors.lastname: González
authors.forename: M de Los Ángeles
authors.initials: Mde L
authors.lastname: Cabrera
authors.forename: M Josefa
authors.initials: MJ
authors.lastname: Henríquez
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Contreras
authors.forename: Bernardo
authors.initials: B
authors.lastname: Morales
authors.forename: Alejandra
authors.initials: A
authors.lastname: Moenne
mesh_terms: D000968:Antimycin A / Q000378:metabolism / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000378:metabolism / Q000494:pharmacology; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism; D002147:Calmodulin / Q000235:genetics / Q000378:metabolism; D002243:Carbolines / Q000378:metabolism / Q000494:pharmacology; D002470:Cell Survival; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism; D002952:Citric Acid Cycle; D003300:Copper / Q000494:pharmacology*; D004579:Electron Transport; D004789:Enzyme Activation; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010879:Piperazines / Q000378:metabolism / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D012433:Ryanodine / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors; D015533:Transcriptional Activation; D044445:Ulva / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D000968:Antimycin A; D002118:Calcium; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002147:Calmodulin; D002243:Carbolines; D003300:Copper; D006861:Hydrogen Peroxide; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D010879:Piperazines; D010940:Plant Proteins; D011494:Protein Kinases; D012433:Ryanodine; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C539827:1-(3-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-4-methoxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido(3,4-b)indole-3-carboxylic acid