The Experts below are selected from a list of 4872 Experts worldwide ranked by ideXlab platform
Blas Lotinahennsen - One of the best experts on this subject based on the ideXlab platform.
-
friedelane triterpenes from celastrus vulcanicola as photosynthetic inhibitors
Journal of Agricultural and Food Chemistry, 2010Co-Authors: David Torresromero, Beatriz Kingdiaz, Blas Lotinahennsen, Reto J Strasser, Ignacio A Jimenez, Isabel L BazzocchiAbstract:Five friedelane triterpenoids, epifriedelinol (1), friedelin (2), canophyllol (3), pulpononic acid (4) and 3-oxo-29-hydroxyfriedelane (5), were isolated from Celastrus vulcanicola (Celastraceae), and were identified by spectroscopic methods, comparison with authentic samples and reported data. In the search for potential herbicides, compounds 1-5 were evaluated for their photosynthetic inhibitory activity. Compound 1 acts as an energy transfer inhibitor, interacting and enhancing the light-activated Mg(2+)-ATPase, while 3 behaves as a Hill Reaction inhibitor. The in vivo assays indicated that 1 and 3 act as selective postemergence herbicides at 100 μM by reducing biomass production in the weed Physalis ixocarpa. Moreover, results from Chl a fluorescence transients in leaves of Lolium perenne and P. ixocarpa suggest that both compounds affect photosynthesis efficiency of the chloroplasts as a response to a process of detoxification and repair. Thus, 1 and 3 reduce biomass by more complex mechanisms than only the damaging of the photosynthetic apparatus.
-
siderin from toona ciliata meliaceae as photosystem ii inhibitor on spinach thylakoids
Archives of Biochemistry and Biophysics, 2007Co-Authors: Thiago A. M. Veiga, Beatriz Kingdiaz, Maria Fátima Das Graças Fernandes Da ,silva, Raquel Gonzalezvazquez, Joao Neto, Blas LotinahennsenAbstract:Abstract Four natural products were isolated from plants of the Rutaceae and Meliaceae families and their effect on photosynthesis was tested. Siderin ( 1 ) inhibited both ATP synthesis and electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV); therefore, it acts as Hill Reaction inhibitor in freshly lysed spinach thylakoids. Natural products 2 – 4 were inactive. Secondary metabolite 1 did not inhibit PSI electron transport. It inhibits partial Reactions of PSII electron flow from water to 2,6-dichlorophenol indophenol (DCPIP), from water to sodium silicomolybdate, and partially inhibits electron flow from diphenylcarbazid (DPC) to DCPIP. These results established that the site of inhibition of 1 was at the donor and acceptor sides of PSII, between P 680 and Q A . Chlorophyll a fluorescence measurements confirmed the behavior of the Toona ciliate coumarin 1 as P 680 to Q A inhibitor by the creation of silent centers. May be this is the mechanisms of action of 1 and is the way in which it develops a phytotoxic activity against photosynthesis.
-
inhibition of photophosphorylation and electron transport chain in thylakoids by lasiodiplodin a natural product from botryosphaeria rhodina
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Thiago A. M. Veiga, Paulo Cezar Vieira, Maria Fátima Das Graças Fernandes Da ,silva, Sebastião C. Silva, Archundiacamacho Francisco, Edson Rodrigues Filho, Joao B Fernandes, Manfred W Muller, Blas LotinahennsenAbstract:Four natural products were isolated from the fungus Botryosphaeria rhodina, and their effects on photosynthesis were tested. Only lasiodiplodin (1) inhibited ATP synthesis and electron flow from water to methylviologen; therefore, it acts as a Hill Reaction inhibitor in freshly lysed spinach thylakoids. Photosystem I and II and partial Reactions as well as ATPase were measured in the presence of 1. Three new different sites of 1 interaction and inhibition were found: one at CF1, the second in the water-splitting enzyme, and the third at the electron-transfer path between P680 and QA; these targets are different from that of the synthetic herbicides present. Electron transport chain inhibition by 1 was corroborated by fluorescence induction kinetics studies.
-
a diterpene γ lactone derivative from pterodon polygalaeflorus benth as a photosystem ii inhibitor and uncoupler of photosynthesis
Zeitschrift für Naturforschung C, 2006Co-Authors: Beatriz Kingdiaz, Flavio Dos J L Santos, Mayura M M Rubinger, Dorila Piloveloso, Blas LotinahennsenAbstract:6alpha,7beta-Dihydroxyvouacapan-17beta-oic acid (1) was isolated from Pterodon polygalaeflorus Benth. Modification of 1 yielded 6alpha-hydroxyvouacapan-7beta,17beta-lactone (2) and then 6-oxovouacapan-7beta,17beta-lactone (3). Photosynthesis inhibition by 3 was evaluated in spinach chloroplasts. The uncoupled non-cyclic electron transport rate and ATP synthesis were inhibited by 3, which behaved as a Hill Reaction inhibitor. Furthermore, 3 acted as an uncoupler because it enhanced the basal and phosphorylating electron transport rate on thylakoids. This last property of 3 was corroborated when it was observed that it enhances the Mg2+-ATPase activity. In contrast, 3 did not affect photosystem I (PSI) activity. Analysis of the partial photosystem II (PSII) Reactions from water to DCPIPOX and water to silicomolybdate allowed to locate the inhibition sites at the redox components of PSII. The OJIP test of the chlorophyll a fluorescence transient confirmed that the inhibition sites were 1.) the oxygen-evolving complex (OEC) and 2.) by the formation of silent centers in the non-QA reducing centers.
-
natural diterpene β lactone derivative as photosystem ii inhibitor on spinach chloroplasts
Pesticide Biochemistry and Physiology, 2006Co-Authors: Beatriz Kingdiaz, America Perezreyes, Flavio Dos J L Santos, Dalton L Ferreiraalves, Dorila Pilo Veloso, Salvador Uribe Carvajal, Blas LotinahennsenAbstract:Abstract α,7β-Dihydroxyvouacapan-17β-oic acid ( 1 ) was isolated from Pterodon polygalaeflorus Benth. Then, ( 1 ) was modified to obtain 6α-hydroxyvouacapan-7β,17β-lactone ( 2 ). Inhibition properties of both ( 1 ) and ( 2 ) were evaluated in spinach chloroplasts. Only compound ( 2 ) inhibited non-cyclic electron transport and ATP synthesis, i.e., ( 2 ) behaved as a Hill Reaction inhibitor. Compound ( 2 ) did not affect photosystem I (PSI) activity but it did inhibit electron flow through PSII. Analysis of the partial PSII Reactions from water to DCPIP ox , water to silicomolybdate, and diphenylcarbazide to DCPIP ox allowed locating inhibition sites at (i) the oxygen-evolving complex (OEC) and (ii) the redox enzymes of the electron transport chain, in the span of P 680 to Q A . Chlorophyll a fluorescence measurements confirmed the action site for ( 2 ).
Beatriz Kingdiaz - One of the best experts on this subject based on the ideXlab platform.
-
friedelane triterpenes from celastrus vulcanicola as photosynthetic inhibitors
Journal of Agricultural and Food Chemistry, 2010Co-Authors: David Torresromero, Beatriz Kingdiaz, Blas Lotinahennsen, Reto J Strasser, Ignacio A Jimenez, Isabel L BazzocchiAbstract:Five friedelane triterpenoids, epifriedelinol (1), friedelin (2), canophyllol (3), pulpononic acid (4) and 3-oxo-29-hydroxyfriedelane (5), were isolated from Celastrus vulcanicola (Celastraceae), and were identified by spectroscopic methods, comparison with authentic samples and reported data. In the search for potential herbicides, compounds 1-5 were evaluated for their photosynthetic inhibitory activity. Compound 1 acts as an energy transfer inhibitor, interacting and enhancing the light-activated Mg(2+)-ATPase, while 3 behaves as a Hill Reaction inhibitor. The in vivo assays indicated that 1 and 3 act as selective postemergence herbicides at 100 μM by reducing biomass production in the weed Physalis ixocarpa. Moreover, results from Chl a fluorescence transients in leaves of Lolium perenne and P. ixocarpa suggest that both compounds affect photosynthesis efficiency of the chloroplasts as a response to a process of detoxification and repair. Thus, 1 and 3 reduce biomass by more complex mechanisms than only the damaging of the photosynthetic apparatus.
-
siderin from toona ciliata meliaceae as photosystem ii inhibitor on spinach thylakoids
Archives of Biochemistry and Biophysics, 2007Co-Authors: Thiago A. M. Veiga, Beatriz Kingdiaz, Maria Fátima Das Graças Fernandes Da ,silva, Raquel Gonzalezvazquez, Joao Neto, Blas LotinahennsenAbstract:Abstract Four natural products were isolated from plants of the Rutaceae and Meliaceae families and their effect on photosynthesis was tested. Siderin ( 1 ) inhibited both ATP synthesis and electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV); therefore, it acts as Hill Reaction inhibitor in freshly lysed spinach thylakoids. Natural products 2 – 4 were inactive. Secondary metabolite 1 did not inhibit PSI electron transport. It inhibits partial Reactions of PSII electron flow from water to 2,6-dichlorophenol indophenol (DCPIP), from water to sodium silicomolybdate, and partially inhibits electron flow from diphenylcarbazid (DPC) to DCPIP. These results established that the site of inhibition of 1 was at the donor and acceptor sides of PSII, between P 680 and Q A . Chlorophyll a fluorescence measurements confirmed the behavior of the Toona ciliate coumarin 1 as P 680 to Q A inhibitor by the creation of silent centers. May be this is the mechanisms of action of 1 and is the way in which it develops a phytotoxic activity against photosynthesis.
-
a diterpene γ lactone derivative from pterodon polygalaeflorus benth as a photosystem ii inhibitor and uncoupler of photosynthesis
Zeitschrift für Naturforschung C, 2006Co-Authors: Beatriz Kingdiaz, Flavio Dos J L Santos, Mayura M M Rubinger, Dorila Piloveloso, Blas LotinahennsenAbstract:6alpha,7beta-Dihydroxyvouacapan-17beta-oic acid (1) was isolated from Pterodon polygalaeflorus Benth. Modification of 1 yielded 6alpha-hydroxyvouacapan-7beta,17beta-lactone (2) and then 6-oxovouacapan-7beta,17beta-lactone (3). Photosynthesis inhibition by 3 was evaluated in spinach chloroplasts. The uncoupled non-cyclic electron transport rate and ATP synthesis were inhibited by 3, which behaved as a Hill Reaction inhibitor. Furthermore, 3 acted as an uncoupler because it enhanced the basal and phosphorylating electron transport rate on thylakoids. This last property of 3 was corroborated when it was observed that it enhances the Mg2+-ATPase activity. In contrast, 3 did not affect photosystem I (PSI) activity. Analysis of the partial photosystem II (PSII) Reactions from water to DCPIPOX and water to silicomolybdate allowed to locate the inhibition sites at the redox components of PSII. The OJIP test of the chlorophyll a fluorescence transient confirmed that the inhibition sites were 1.) the oxygen-evolving complex (OEC) and 2.) by the formation of silent centers in the non-QA reducing centers.
-
natural diterpene β lactone derivative as photosystem ii inhibitor on spinach chloroplasts
Pesticide Biochemistry and Physiology, 2006Co-Authors: Beatriz Kingdiaz, America Perezreyes, Flavio Dos J L Santos, Dalton L Ferreiraalves, Dorila Pilo Veloso, Salvador Uribe Carvajal, Blas LotinahennsenAbstract:Abstract α,7β-Dihydroxyvouacapan-17β-oic acid ( 1 ) was isolated from Pterodon polygalaeflorus Benth. Then, ( 1 ) was modified to obtain 6α-hydroxyvouacapan-7β,17β-lactone ( 2 ). Inhibition properties of both ( 1 ) and ( 2 ) were evaluated in spinach chloroplasts. Only compound ( 2 ) inhibited non-cyclic electron transport and ATP synthesis, i.e., ( 2 ) behaved as a Hill Reaction inhibitor. Compound ( 2 ) did not affect photosystem I (PSI) activity but it did inhibit electron flow through PSII. Analysis of the partial PSII Reactions from water to DCPIP ox , water to silicomolybdate, and diphenylcarbazide to DCPIP ox allowed locating inhibition sites at (i) the oxygen-evolving complex (OEC) and (ii) the redox enzymes of the electron transport chain, in the span of P 680 to Q A . Chlorophyll a fluorescence measurements confirmed the action site for ( 2 ).
-
phytochemical and biochemical characterization of epimeric photogedunin derivatives their different sites of interaction on the redox electron transport carrier of spinacea oleracea l chloroplasts
Journal of Agricultural and Food Chemistry, 1998Co-Authors: Carlos L Cespedes, Beatriz Kingdiaz, Jose S Calderon, Blas LotinahennsenAbstract:Bioactivity-directed fractionation of the dichloromethane extract of the heartwood of Cedrela salvadorensis L. resulted in the isolation of two epimeric photogedunins and in the acquirement of two bioactive epimeric photogedunin acetates 3 (β) and 4 (α) at the C-23 position. Compounds 3 and 4 inhibited photophosphorylation, H+-uptake, and noncyclic electron flow from water to methyl viologen (basal, phosphorylating, and uncoupled). Inhibiton of all photosynthetic activities require 3 min of preincubation in the light before inhibition is observed. The results indicate that compounds 3 and 4 behave as Hill Reaction inhibitors. α-Photogedunin acetate 3 inhibits PS II electron flow from H2O to DCBQ without affecting PS I electron transport from reduced DCPIP to MV and PSII from water to SiMo. Therefore, its target is localized at the QB level. β-Photogedunin acetate 4 inhibits PS I electron flow from reduced DCPIP to MV, PMSred to MV, and TMQH2 to MV without affecting PS II electron flow, interacting at the ...
Jose Antonio Lucas - One of the best experts on this subject based on the ideXlab platform.
-
spent metal working fluids produced alterations on photosynthetic parameters and cell ultrastructure of leaves and roots of maize plants
Journal of Hazardous Materials, 2013Co-Authors: Lucia Grijalbo, Mercedes Fernandezpascual, Daniel Garciaseco, Francisco Javier Gutierrezmanero, Jose Antonio LucasAbstract:In this work we assess the capacity of maize (Zea mays) plants to phytoremediate spent metal working fluids (MWFs) and its effects on photosynthesis and ultrastructure of mesophyll and root cells. A corn-esparto fibre system patented by us has been used to phytoremediate MWFs in hydroponic culture. Furthermore, a plant growth promoting rhizobacteria (PGPR) has been used to improve the process. The results show that this system is capable of significantly reducing the chemical oxygen demand, under local legislation limits. However, plant systems are really damaged, mainly its photosynthetic system, as shown by the photosynthetical parameters. Nevertheless, strain inoculated improves these parameters, especially Hill Reaction. The ultrastructure of photosynthetic apparatus was also affected. Chloroplast number decreased and becomes degraded in the mesophyll of MWFs treated plants. In some cases even plasmolysis of chloroplast membrane was detected. Early senescence symptoms were detected in root ultrastructural study. Severe cellular damage was observed in the parenchymal root cells of plants grown with MWFs, while vascular bundles cell remained unchanged. It seems that the inoculation minimises the damage originated by the MWFs pollutants, appearing as less degenerative organelles and higher chloroplast number than in non-inoculated ones.
Thiago A. M. Veiga - One of the best experts on this subject based on the ideXlab platform.
-
Natural products from Pluchea sagittalis act as inhibitors of photosynthesis in vitro
2017Co-Authors: Ana C. Carvalho, Blas Lotina-hennsen, João C. S. Lira, Thaís M. Pereira, Sebastião C. Silva, Simone Y. Simote-silva, Fernando K. D. Oliveira, Beatriz King-diaz, Thiago A. M. VeigaAbstract:Four compounds were isolated from roots and aerial parts of Pluchea sagittalis (Asteraceae), 3, 5-dihydroxy-6, 7, 3′, 4′-tetramethoxiflavunol (1), 5-hydroxymethylfurfural (2), 3, 4-dimethoxybenzaldehyde (3) and 2, 3, 4-trihydroxybenzaldeyde (4). Their herbicidal potential was detected by polarographic techniques. All of them inhibited the non-cyclic electron transport on basal, phosphorylating and uncoupled conditions from H2O to methylviologen (MV); thus, they act as Hill Reaction inhibitors. Studies on fluorescence of chlorophyll a (ChL a) indicated they have different modes of interaction and inhibition sites on the photosystem II electron transport chain; 1–3 have interacted with the acceptor side while 4 has interacted at the donor side.
-
Ácido myrsinoico a e derivado: inibidores da fotossíntese in vitro
Sociedade Brasileira de Química, 2012Co-Authors: Marcela Carmen De M. Burger, Gracielle S. De Oliveira, Antônio Carlos S. Menezes, Paulo Cezar Vieira, Maria Fátima Das G. F. Da Silva, Thiago A. M. VeigaAbstract:Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methylviologen; therefore, they act as Hill Reaction inhibitors in spinach thylakoids. They inhibited partial Reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P680 and Q A. Chlorophyll a fluorescence measurements confirmed the behavior of the compounds (pool of quinones)
-
siderin from toona ciliata meliaceae as photosystem ii inhibitor on spinach thylakoids
Archives of Biochemistry and Biophysics, 2007Co-Authors: Thiago A. M. Veiga, Beatriz Kingdiaz, Maria Fátima Das Graças Fernandes Da ,silva, Raquel Gonzalezvazquez, Joao Neto, Blas LotinahennsenAbstract:Abstract Four natural products were isolated from plants of the Rutaceae and Meliaceae families and their effect on photosynthesis was tested. Siderin ( 1 ) inhibited both ATP synthesis and electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV); therefore, it acts as Hill Reaction inhibitor in freshly lysed spinach thylakoids. Natural products 2 – 4 were inactive. Secondary metabolite 1 did not inhibit PSI electron transport. It inhibits partial Reactions of PSII electron flow from water to 2,6-dichlorophenol indophenol (DCPIP), from water to sodium silicomolybdate, and partially inhibits electron flow from diphenylcarbazid (DPC) to DCPIP. These results established that the site of inhibition of 1 was at the donor and acceptor sides of PSII, between P 680 and Q A . Chlorophyll a fluorescence measurements confirmed the behavior of the Toona ciliate coumarin 1 as P 680 to Q A inhibitor by the creation of silent centers. May be this is the mechanisms of action of 1 and is the way in which it develops a phytotoxic activity against photosynthesis.
-
inhibition of photophosphorylation and electron transport chain in thylakoids by lasiodiplodin a natural product from botryosphaeria rhodina
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Thiago A. M. Veiga, Paulo Cezar Vieira, Maria Fátima Das Graças Fernandes Da ,silva, Sebastião C. Silva, Archundiacamacho Francisco, Edson Rodrigues Filho, Joao B Fernandes, Manfred W Muller, Blas LotinahennsenAbstract:Four natural products were isolated from the fungus Botryosphaeria rhodina, and their effects on photosynthesis were tested. Only lasiodiplodin (1) inhibited ATP synthesis and electron flow from water to methylviologen; therefore, it acts as a Hill Reaction inhibitor in freshly lysed spinach thylakoids. Photosystem I and II and partial Reactions as well as ATPase were measured in the presence of 1. Three new different sites of 1 interaction and inhibition were found: one at CF1, the second in the water-splitting enzyme, and the third at the electron-transfer path between P680 and QA; these targets are different from that of the synthetic herbicides present. Electron transport chain inhibition by 1 was corroborated by fluorescence induction kinetics studies.
Maria Fátima Das Graças Fernandes Da ,silva - One of the best experts on this subject based on the ideXlab platform.
-
Furoquinoline alkaloids isolated from Balfourodendron riedelianum as photosynthetic inhibitors in spinach chloroplasts
'Elsevier BV', 2013Co-Authors: Veiga, Thiago Andre Moura, Vieira, Paulo Cezar, Maria Fátima Das Graças Fernandes Da ,silva, Sampaio, Olivia Moreira, King-diaz Beatriz, Marques, Anna Sylvia Ferrari, Lotina-hennsen BiasAbstract:In the search for natural inhibitors of plant growth, we investigate the mechanism of action of the natural furoquinoline alkaloids isolated from Balfourodendron riedelianum (Rutaceae): evolitrine (1), kokusaginine (2), gamma-fagarine (3), skimmianine (4) and maculosidine (5) on the photosynthesis light Reactions. Their effect on the electron transport chain on thylakoids was analyzed. Alkaloids 1, 2, 4 and 5 inhibited ATP synthesis, basal, phosphorylating and uncoupled electron transport acting as Hill Reaction inhibitors on spinach chloroplasts. Alkaloid 3 was not active. the inhibition and interaction site of alkaloids 1, 2, 4 and 5 on the non-cyclic electron transport chain was studied by polarography and fluorescence of the chlorophyll a (Chl a). the results indicate that the target for 1 was localized on the donor and acceptor side of PS II. in addition alkaloids 2 and 5 affect the PS I electron acceptors on leaf discs. (C) 2013 Elsevier B.V. All rights reserved.DGAPA-UNAM grant PAPIT from Faculty of Chemistry UNAMDGAPA-UNAM grant PAIP from Faculty of Chemistry UNAMFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo Unifesp, Inst Ciencias Ambientais Quim & Farmaceut, BR-09972270 Diadema, SP, BrazilUniv Fed Sao Carlos UFSCar, Dept Quim, BR-13565905 Sao Carlos, SP, BrazilUniv Nacl Autonoma Mexico, Dept Bioquim, Fac Quim, Mexico City 04510, DF, MexicoUniversidade Federal de São Paulo Unifesp, Inst Ciencias Ambientais Quim & Farmaceut, BR-09972270 Diadema, SP, BrazilDGAPA-UNAM grant PAPIT from Faculty of Chemistry UNAM: IT102012-3DGAPA-UNAM grant PAIP from Faculty of Chemistry UNAM: 4290-03Web of Scienc
-
Myrsinoic a acid and its derivative: in vitro inhibitors of photosynthesis
Sociedade Brasileira de Química, 2012Co-Authors: Burger, Marcela Carmen De Melo, Gracielle S. De Oliveira, Menezes, Antônio Carlos Severo, Vieira, Paulo Cezar, Maria Fátima Das Graças Fernandes Da ,silva, Veiga, Thiago Andre Moura [unifesp]Abstract:Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methylviologen; therefore, they act as Hill Reaction inhibitors in spinach thylakoids. They inhibited partial Reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P680 and Q A. Chlorophyll a fluorescence measurements confirmed the behavior of the compounds (pool of quinones)
-
Myrsinoic a acid and its derivative: in vitro inhibitors of photosynthesis
'FapUNIFESP (SciELO)', 2012Co-Authors: Burger, Marcela Carmen De Melo, Gracielle S. De Oliveira, Menezes, Antônio Carlos Severo, Vieira, Paulo Cezar, Maria Fátima Das Graças Fernandes Da ,silva, Veiga, Thiago Andre MouraAbstract:Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methylviologen; therefore, they act as Hill Reaction inhibitors in spinach thylakoids. They inhibited partial Reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P680 and Q A. Chlorophyll a fluorescence measurements confirmed the behavior of the compounds (pool of quinones).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual de Goiás Unidade Universitária de Ciências Exatas e TecnológicasUniversidade Federal de São Carlos Departamento de QuímicaUniversidade Federal de São Paulo (UNIFESP) Instituto de Ciências Ambientais, Químicas e Farmacêuticas Departamento de Ciências Exatas e da TerraUNIFESP, Instituto de Ciências Ambientais, Químicas e Farmacêuticas Depto. de Ciências Exatas e da TerraSciEL
-
siderin from toona ciliata meliaceae as photosystem ii inhibitor on spinach thylakoids
Archives of Biochemistry and Biophysics, 2007Co-Authors: Thiago A. M. Veiga, Beatriz Kingdiaz, Maria Fátima Das Graças Fernandes Da ,silva, Raquel Gonzalezvazquez, Joao Neto, Blas LotinahennsenAbstract:Abstract Four natural products were isolated from plants of the Rutaceae and Meliaceae families and their effect on photosynthesis was tested. Siderin ( 1 ) inhibited both ATP synthesis and electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV); therefore, it acts as Hill Reaction inhibitor in freshly lysed spinach thylakoids. Natural products 2 – 4 were inactive. Secondary metabolite 1 did not inhibit PSI electron transport. It inhibits partial Reactions of PSII electron flow from water to 2,6-dichlorophenol indophenol (DCPIP), from water to sodium silicomolybdate, and partially inhibits electron flow from diphenylcarbazid (DPC) to DCPIP. These results established that the site of inhibition of 1 was at the donor and acceptor sides of PSII, between P 680 and Q A . Chlorophyll a fluorescence measurements confirmed the behavior of the Toona ciliate coumarin 1 as P 680 to Q A inhibitor by the creation of silent centers. May be this is the mechanisms of action of 1 and is the way in which it develops a phytotoxic activity against photosynthesis.
-
inhibition of photophosphorylation and electron transport chain in thylakoids by lasiodiplodin a natural product from botryosphaeria rhodina
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Thiago A. M. Veiga, Paulo Cezar Vieira, Maria Fátima Das Graças Fernandes Da ,silva, Sebastião C. Silva, Archundiacamacho Francisco, Edson Rodrigues Filho, Joao B Fernandes, Manfred W Muller, Blas LotinahennsenAbstract:Four natural products were isolated from the fungus Botryosphaeria rhodina, and their effects on photosynthesis were tested. Only lasiodiplodin (1) inhibited ATP synthesis and electron flow from water to methylviologen; therefore, it acts as a Hill Reaction inhibitor in freshly lysed spinach thylakoids. Photosystem I and II and partial Reactions as well as ATPase were measured in the presence of 1. Three new different sites of 1 interaction and inhibition were found: one at CF1, the second in the water-splitting enzyme, and the third at the electron-transfer path between P680 and QA; these targets are different from that of the synthetic herbicides present. Electron transport chain inhibition by 1 was corroborated by fluorescence induction kinetics studies.