Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
Plant J ; 103(2): 814-823, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32314445

RESUMO

C4 plants can fix CO2 efficiently using CO2 -concentrating mechanisms (CCMs), but they require additional ATP. To supply the additional ATP, C4 plants operate at higher rates of cyclic electron transport around photosystem I (PSI), in which electrons are transferred from ferredoxin to plastoquinone. Recently, it has been reported that the NAD(P)H dehydrogenase-like complex (NDH) accumulated in the thylakoid membrane in leaves of C4 plants, making it a candidate for the additional synthesis of ATP used in the CCM. In addition, C4 plants have higher levels of PROTON GRADIENT REGULATION 5 (PGR5) expression, but it has been unknown how PGR5 functions in C4 photosynthesis. In this study, PGR5 was overexpressed in a C4 dicot, Flaveria bidentis. In PGR5-overproducing (OP) lines, PGR5 levels were 2.3- to 3.0-fold greater compared with wild-type plants. PGR5-like PHOTOSYNTHETIC PHENOTYPE 1 (PGRL1), which cooperates with PGR5, increased with PGR5. A spectroscopic analysis indicated that in the PGR5-OP lines, the acceptor side limitation of PSI was reduced in response to a rapid increase in photon flux density. Although it did not affect CO2 assimilation, the overproduction of PGR5 contributed to an enhanced electron sink downstream of PSI.


Assuntos
Flaveria/metabolismo , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Dióxido de Carbono/metabolismo , Clorofila/metabolismo , Transporte de Elétrons , Regulação da Expressão Gênica de Plantas , NADP/metabolismo , Oxirredução , Ribulose-Bifosfato Carboxilase/metabolismo
2.
Plant Cell Physiol ; 61(7): 1252-1261, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32333781

RESUMO

Angiosperms have three PsbQ-like (PQL) proteins in addition to the PsbQ subunit of the oxygen-evolving complex of photosystem II. Previous studies have shown that two PQL proteins, PnsL2 and PnsL3, are subunits of the chloroplast NADH dehydrogenase-like (NDH) complex involved in the photosystem I (PSI) cyclic electron flow. In addition, another PsbQ homolog, PQL3, is required for the NDH activity; however, the molecular function of PQL3 has not been elucidated. Here, we show that PQL3 is an assembly factor, particularly for the accumulation of subcomplex B (SubB) of the chloroplast NDH. In the pql3 mutant of Arabidopsis thaliana, the amounts of NDH subunits in SubB, PnsB1 and PsnB4, were decreased, causing a severe reduction in the NDH-PSI supercomplex. Analysis using blue native polyacrylamide gel electrophoresis suggested that the incorporation of PnsL3 into SubB was affected in the pql3 mutant. Unlike other PsbQ homologs, PQL3 was weakly associated with thylakoid membranes and was only partially protected from thermolysin digestion. Consistent with the function as an assembly factor, PQL3 accumulated independently in other NDH mutants, such as pnsl1-3. Furthermore, PQL3 accumulated in young leaves in a manner similar to the accumulation of CRR3, an assembly factor for SubB. These results suggest that PQL3 has developed a distinct function as an assembly factor for the NDH complex during evolution of the PsbQ protein family in angiosperms.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/metabolismo , Cloroplastos/enzimologia , NADH Desidrogenase/metabolismo , Complexo de Proteína do Fotossistema II/fisiologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Cloroplastos/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/genética , Complexo de Proteína do Fotossistema II/metabolismo , Filogenia , Folhas de Planta/metabolismo , Tilacoides/metabolismo
3.
Theor Appl Genet ; 133(4): 1291-1301, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31980835

RESUMO

KEY MESSAGE: Novel drought tolerance genes were identified by screening thousands of random genomic fragments from grass species in transgenic rice. Identification of agronomically important genes is a critical step for crop breeding through biotechnology. Multiple approaches have been employed to identify new gene targets, including comprehensive screening platforms for gene discovery such as the over-expression of libraries of cDNA clones. In this study, random genomic fragments from plants were introduced into rice and screened for drought tolerance in a high-throughput manner with the aim of finding novel genetic elements not exclusively limited to coding sequences. To illustrate the power of this approach, genomic libraries were constructed from four grass species, and screening a total of 50,825 transgenic rice lines for drought tolerance resulted in the identification of 12 reproducibly efficacious fragments. Of the twelve, two were from the mitochondrial genome of signal grass and ten were from the nuclear genome of buffalo grass. Subsequent sequencing and analyses revealed that the ten fragments from buffalo grass carried a similar genetic element with no significant homology to any previously characterized gene. The deduced protein sequence was rich in acidic amino acid residues in the C-terminal half, and two of the glutamic acid residues in the C-terminal half were shown to play an important role in drought tolerance. The results demonstrate that an open-ended screening approach using random genomic fragments could discover trait genes distinct from gene discovery based on known pathways or biased toward coding sequence over-expression.


Assuntos
Adaptação Fisiológica/genética , Secas , Genes de Plantas , Ensaios de Triagem em Larga Escala , Oryza/genética , Oryza/fisiologia , Sequência de Aminoácidos , Biblioteca Gênica , Peptídeos/química , Fenótipo , Plantas Geneticamente Modificadas , Reprodutibilidade dos Testes , Transcrição Gênica
4.
Plant Cell Physiol ; 57(10): 2020-2028, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27497446

RESUMO

C4 photosynthesis exhibits efficient CO2 assimilation in ambient air by concentrating CO2 around ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) through a metabolic pathway called the C4 cycle. It has been suggested that cyclic electron flow (CEF) around PSI mediated by chloroplast NADH dehydrogenase-like complex (NDH), an alternative pathway of photosynthetic electron transport (PET), plays a crucial role in C4 photosynthesis, although the contribution of NDH-mediated CEF is small in C3 photosynthesis. Here, we generated NDH-suppressed transformants of a C4 plant, Flaveria bidentis, and showed that the NDH-suppressed plants grow poorly, especially under low-light conditions. CO2 assimilation rates were consistently decreased in the NDH-suppressed plants under low and medium light intensities. Measurements of non-photochemical quenching (NPQ) of Chl fluorescence, the oxidation state of the reaction center of PSI (P700) and the electrochromic shift (ECS) of pigment absorbance indicated that proton translocation across the thylakoid membrane is impaired in the NDH-suppressed plants. Since proton translocation across the thylakoid membrane induces ATP production, these results suggest that NDH-mediated CEF plays a role in the supply of ATP which is required for C4 photosynthesis. Such a role is more crucial when the light that is available for photosynthesis is limited and the energy production by PET becomes rate-determining for C4 photosynthesis. Our results demonstrate that the physiological contribution of NDH-mediated CEF is greater in C4 photosynthesis than in C3 photosynthesis, suggesting that the mechanism of PET in C4 photosynthesis has changed from that in C3 photosynthesis accompanying the changes in the mechanism of CO2 assimilation.


Assuntos
Carbono/metabolismo , Flaveria/enzimologia , NADH Desidrogenase/metabolismo , Fotossíntese , Complexo de Proteína do Fotossistema I/metabolismo , Proteínas de Plantas/metabolismo , Dióxido de Carbono/metabolismo , Transporte de Elétrons/efeitos da radiação , Flaveria/crescimento & desenvolvimento , Flaveria/efeitos da radiação , Luz , Fotossíntese/efeitos da radiação , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Interferência de RNA , Análise Espectral , Supressão Genética/efeitos da radiação , Transformação Genética/efeitos da radiação
5.
Photosynth Res ; 129(3): 261-77, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27017612

RESUMO

By concentrating CO2, C4 photosynthesis can suppress photorespiration and achieve high photosynthetic efficiency, especially under conditions of high light, high temperature, and drought. To concentrate CO2, extra ATP is required, which would also require a change in photosynthetic electron transport in C4 photosynthesis from that in C3 photosynthesis. Several analyses have shown that the accumulation of the components of cyclic electron flow (CEF) around photosystem I, which generates the proton gradient across thylakoid membranes (ΔpH) and functions in ATP production without producing NADPH, is increased in various NAD-malic enzyme and NADP-malic enzyme C4 plants, suggesting that CEF may be enhanced to satisfy the increased need for ATP in C4 photosynthesis. However, in C4 plants, the accumulation patterns of the components of two partially redundant pathways of CEF, NAD(P)H dehydrogenase-like complex and PROTON GRADIENT REGULATION5-PGR5-like1 complex, are not identical, suggesting that these pathways may play different roles in C4 photosynthesis. Accompanying the increase in the amount of NDH, the expression of some genes which encode proteins involved in the assembly of NDH is also increased at the mRNA level in various C4 plants, suggesting that this increase is needed to increase the accumulation of NDH. To better understand the relation between CEF and C4 photosynthesis, a reverse genetic approach to generate C4 transformants with respect to CEF will be necessary.


Assuntos
Trifosfato de Adenosina/metabolismo , Arabidopsis/metabolismo , Malato Desidrogenase/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/metabolismo , Dióxido de Carbono/metabolismo , Transporte de Elétrons , Elétrons , Fotossíntese , Tilacoides/metabolismo
6.
Health Econ Rev ; 2(1): 10, 2012 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-22827922

RESUMO

We propose simple modifications for the Kakwani tax progressivity measure that make it suitable for evaluating access inequality for medical services. Our modification is to measure inequality using the ratio of the concentration index to the Gini coefficient instead of the difference between them. We also propose a measure using the Gini coefficient or concentration index of consumption expenditure as the denominator in the modified measure as an alternative type of modified measure. This measure can also be interpreted as the income/consumption expenditure elasticity evaluated at the mean. Additionally, we propose a decomposition method using expenditure components and provide an empirical example with Japanese data.

7.
Mol Plant Microbe Interact ; 25(1): 18-27, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21916556

RESUMO

Mixed infection of Cucumber mosaic virus (CMV) and Turnip mosaic virus (TuMV) induced more severe symptoms on Nicotiana benthamiana than single infection. To dissect the relationships between spatial infection patterns and the 2b protein (2b) of CMV in single or mixed infections, the CMV vectors expressing enhanced green fluorescent or Discosoma sp. red fluorescent proteins (EGFP [EG] or DsRed2 [Ds], respectively were constructed from the same wild-type CMV-Y and used for inoculation onto N. benthamiana. CMV2-A1 vector (C2-A1 [A1]) has a functional 2b while CMV-H1 vector (C2-H1 [H1]) is 2b deficient. As we expected from the 2b function as an RNA silencing suppressor (RSS), in a single infection, A1Ds retained a high level of accumulation at initial infection sites and showed extensive fluorescence in upper, noninoculated leaves, whereas H1Ds disappeared rapidly at initial infection sites and could not spread efficiently in upper, noninoculated leaf tissues. In various mixed infections, we found two phenomena providing novel insights into the relationships among RSS, viral synergism, and interference. First, H1Ds could not spread efficiently from vasculature into nonvascular tissues with or without TuMV, suggesting that RNA silencing was not involved in CMV unloading from vasculature. These results indicated that 2b could promote CMV to unload from vasculature into nonvascular tissues, and that this 2b function might be independent of its RSS activity. Second, we detected spatial interference (local interference) between A1Ds and A1EG in mixed infection with TuMV, between A1Ds (or H1Ds) and TuMV, and between H1Ds and H1EG. This observation suggested that local interference between two viruses was established even in the synergism between CMV and TuMV and, again, RNA silencing did not seem to contribute greatly to this phenomenon.


Assuntos
Cucumovirus/patogenicidade , Doenças das Plantas/virologia , Potyvirus/patogenicidade , RNA Viral/genética , Proteínas Virais/metabolismo , Coinfecção , Cucumovirus/genética , Cucumovirus/fisiologia , DNA Complementar/genética , Expressão Gênica , Proteínas de Fluorescência Verde , Proteínas Luminescentes , Interações Microbianas , Folhas de Planta/virologia , Plantas Geneticamente Modificadas , Potyvirus/genética , Potyvirus/fisiologia , Protoplastos , Interferência de RNA , RNA Mensageiro/genética , Análise de Sequência de DNA , Temperatura , Proteínas Virais/genética
8.
Plant Cell Physiol ; 51(6): 866-76, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20430763

RESUMO

Arabidopsis has three PsbQ-like (PQL) proteins in addition to the PsbQ subunit of the oxygen-evolving complex of PSII. Recent bioinformatic and proteomic studies suggested that the two PQL proteins, PQL1 (At1g14150) and PQL2 (At3g01440), might function in the chloroplast NAD(P)H dehydrogenase (NDH) complex; however, their molecular function has not been characterized. In this study, we examined the function of the chloroplast NDH in the Arabidopsis pql1 and pql2 mutants. Post-illumination increases in Chl fluorescence, which are caused by an NDH-dependent cyclic electron flow, were absent in both mutants, indicating that PQL1 and PQL2 are required for NDH activity. In the thylakoid membranes of wild-type plants, PQL1 and PQL2 were tightly associated with the NDH-PSI supercomplex and protected from protease treatments, while unassembled PQLs were not stably accumulated in mutants lacking known NDH subunits. Subunit stability of the NDH complex was affected differently in the thylakoid membranes of the pql1 and pql2 mutants. These data indicate that PQL1 and PQL2 are novel NDH subunits and differ in their functional roles and in their binding sites in the NDH complex. Furthermore, functional analysis on PQL3 (At2g01918) using the pql3 mutant suggests that PQL3 is also required for NDH activity. Proteins homologous to each PQL protein are found in various plant species, but not in cyanobacteria, algae, mosses or ferns. These results suggest that seed plants that have NDH activity in chloroplasts specifically developed three PQL proteins for the function of the chloroplast NDH complex.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Cloroplastos/enzimologia , NADPH Desidrogenase/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , DNA Bacteriano/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Mutagênese Insercional , Mutação , NADPH Desidrogenase/genética , Complexo de Proteína do Fotossistema I/metabolismo , Alinhamento de Sequência
9.
Plant Cell Physiol ; 50(2): 383-93, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19122188

RESUMO

The chloroplast NAD(P)H dehydrogenase (NDH) complex, which reduces plastoquinones in thylakoid membranes, is involved in PSI cyclic electron flow and chlororespiration. In addition to land plants, the NDH complex is conserved in cyanobacteria. In this study, we identified a novel NDH-related gene of Arabidopsis, NDH-dependent cyclic electron flow 5 (NDF5, At1g55370). Post-illumination increases in chlorophyll fluorescence were absent in ndf5 mutant plants, which indicated that NDF5 is essential for NDH activity. Sequence analysis did not reveal any known functional motifs in NDF5, but there was some homology in amino acid sequence between NDF5 and NDF2, a known NDH subunit. NDF5 and NDF2 homologs were present in higher plants, but not cyanobacteria. A single homolog, which had similarity to both NDF5 and NDF2, was identified in the moss Physcomitrella patens. Immunoblot analysis showed that NDF5 localizes to membrane fractions of chloroplasts. The stability of NdhH, a subunit of the NDH complex, as well as NDF5 and NDF2, was decreased in ndf5, ndf2 and double ndf2/ndf5 mutants, resulting in a loss of NDH activity in these mutants. These results indicated that both NDF5 and NDF2 have essential functions in the stabilization of the NDH complex. We propose that NDF5 and NDF2 were acquired by land plants during evolution, and that in higher plants both NDF5 and NDF2 are critical to regulate NDH activity and each other's protein stability, as well as the stability of additional NDH subunits.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Cloroplastos/metabolismo , NADPH Desidrogenase/metabolismo , Sequência de Aminoácidos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Clorofila/metabolismo , DNA Bacteriano/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Teste de Complementação Genética , Dados de Sequência Molecular , Mutagênese Insercional , Mutação , Fotossíntese , Filogenia , RNA de Plantas/genética , Alinhamento de Sequência
10.
Plant J ; 57(2): 207-19, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18785996

RESUMO

Chloroplastic NAD(P)H dehydrogenase (NDH) plays a role in cyclic electron flow around photosystem I to produce ATP, especially in adaptation to environmental changes. Although the NDH complex contains 11 subunits that are homologous to NADH:ubiquinone oxidoreductase (complex I; EC 1.6.5.3), recent genetic and biological studies have indicated that NDH also comprises unique subunits. We describe here an in silico approach based on co-expression analysis and phylogenetic profiling that was used to identify 65 genes as potential candidates for NDH subunits. Characterization of 21 Arabidopsis T-DNA insertion mutants among these ndh gene candidates indicated that three novel ndf (NDH-dependent cyclic electron flow) mutants (ndf1, ndf2 and ndf4) had impaired NDH activity as determined by measurement of chlorophyll fluorescence. The amount of NdhH subunit was greatly decreased in these mutants, suggesting that the loss of NDH activity was caused by a defect in accumulation of the NDH complex. In addition, NDF1, NDF2 and NDF4 proteins co-migrated with the NdhH subunit, as shown by blue native electrophoresis. These results strongly suggest that NDF proteins are novel subunits of the NDH complex. Further analysis revealed that the NDF1 and NDF2 proteins were unstable in the mutants lacking hydrophobic subunits of the NDH complex, but were stable in mutants lacking the hydrophilic subunits, suggesting that NDF1 and NDF2 interact with a hydrophobic sub-complex. NDF4 protein was predicted to possess a redox-active iron-sulfur cluster domain that may be involved in the electron transfer.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , NADPH Desidrogenase/metabolismo , Tilacoides/enzimologia , Sequência de Aminoácidos , Arabidopsis/enzimologia , Proteínas de Arabidopsis/genética , Biologia Computacional , DNA Bacteriano/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Dados de Sequência Molecular , Mutagênese Insercional , NADPH Desidrogenase/genética , Filogenia , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , RNA de Plantas/genética , Alinhamento de Sequência , Tilacoides/genética
11.
Bioorg Med Chem ; 17(1): 64-73, 2009 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-19081254

RESUMO

Starting with a series of CC chemokine receptor-4 (CCR4) antagonists developed in a previous study, the potency was improved by replacing the pyrrolidine moiety of N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 2 with a 3-(hydroxymethyl)piperidine. The resulting compound (1'-{4-[(4-chlorophenyl)amino]-6,7-dimethoxyquinazolin-2-yl}-1,4'-bipiperidin-3-yl)methanol 8ic was a strong inhibitor of human/mouse chemotaxis. Oral administration of 8ic showed anti-inflammatory activity in a murine model of acute dermatitis (oxazolone-induced contact hypersensitivity test) in a dose-dependent manner.


Assuntos
Anti-Inflamatórios/síntese química , Quinazolinas/farmacocinética , Receptores CCR4/antagonistas & inibidores , Administração Oral , Aminas , Animais , Anti-Inflamatórios/farmacocinética , Quimiotaxia/efeitos dos fármacos , Dermatite/tratamento farmacológico , Modelos Animais de Doenças , Humanos , Camundongos , Piperidinas , Quinazolinas/farmacologia , Relação Estrutura-Atividade
12.
Bioorg Med Chem ; 16(21): 9457-66, 2008 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-18835179

RESUMO

From a series of 4'-[(trifluoromethyl)pyrazol-1-yl]carboxanilides derived from 4-methyl-4'-[3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl]-1,2,3-thiadiazole-5-carboxanilide, one inhibited thapsigargin-induced Ca2+ influx in Jurkat T cells (IC(50)=77 nM) and exhibited high selectivity for the CRAC channel over the VOC channel (index: >130). Another acted as an inhibitor for both T lymphocyte activation-induced diseases and ovalbumin-induced airway eosinophilia in rats (ED(50)=1.3 mg/kg) p.o.


Assuntos
Anilidas/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Cálcio/metabolismo , Pirazóis/farmacologia , Anilidas/síntese química , Anilidas/química , Animais , Bloqueadores dos Canais de Cálcio/síntese química , Bloqueadores dos Canais de Cálcio/química , Sinalização do Cálcio/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Hipersensibilidade/tratamento farmacológico , Interleucina-2/metabolismo , Células Jurkat , Ativação Linfocitária/efeitos dos fármacos , Masculino , Camundongos , Eosinofilia Pulmonar/induzido quimicamente , Eosinofilia Pulmonar/tratamento farmacológico , Pirazóis/síntese química , Pirazóis/química , Ratos , Ratos Endogâmicos BN , Relação Estrutura-Atividade , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Tapsigargina/farmacologia
13.
J Plant Res ; 121(5): 521-6, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18683022

RESUMO

The activities of electron transport are compared between wild-type Arabidopsis and two Arabidopsis mutants deficient for the chloroplastic NAD(P)H dehydrogenase (NDH) which catalyzes cyclic electron transport around photosystem I. The quantum yield of photosystem II and the degree of non-photochemical quenching of chlorophyll fluorescence were of similar levels in the two NDH-deficient mutants and the wild type under non-stressed standard growth conditions. Stromal over-reduction was induced in Arabidopsis NDH mutants with high light treatment, as is the case in tobacco NDH mutants. However, unlike tobacco mutants, photoinhibition was not observed in the Arabidopsis NDH mutants.


Assuntos
Arabidopsis/enzimologia , Cloroplastos/enzimologia , Transporte de Elétrons , Luz , NADPH Desidrogenase/metabolismo , Arabidopsis/genética , Mutação , NAD(P)H Desidrogenase (Quinona)/metabolismo , Oxirredução
14.
Bioorg Med Chem ; 16(17): 7968-74, 2008 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-18694645

RESUMO

A series of CC chemokine receptor-4 (CCR4) antagonists were examined in a previous report in an attempt to improve metabolic stability in human liver microsomes. In this study, the cycloheptylamine moiety of N-cycloheptyl-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 1 was replaced with the p-chloroaniline moiety, and the resulting compound, N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine (8c), retained its potency ([(35)S]GTPgammaS-binding inhibition and CCL22-induced chemotaxis in humans/mice). Based on the structure-activity relationships (SAR), a homology model was constructed for CCR4 to explain the binding mode of 8c. Overall, there was good agreement between the docking pose of the CCR4 homology model and the human [(35)S]GTPgammaS assay results. Administration of 8c in a murine model of acute dermatitis showed anti-inflammatory activity (oxazolone-induced contact hypersensitivity test).


Assuntos
Simulação por Computador , Modelos Químicos , Quinazolinas/química , Quinazolinas/farmacologia , Receptores CCR4/antagonistas & inibidores , Animais , Sítios de Ligação , Linhagem Celular , Avaliação Pré-Clínica de Medicamentos , Humanos , Injeções Subcutâneas , Camundongos , Modelos Moleculares , Estrutura Molecular , Oxazolona , Quinazolinas/síntese química , Receptores CCR4/química , Dermatopatias/induzido quimicamente , Dermatopatias/tratamento farmacológico , Dermatopatias/patologia , Estereoisomerismo , Relação Estrutura-Atividade
15.
Bioorg Med Chem ; 16(14): 7021-32, 2008 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-18539035

RESUMO

A new series of quinazolines that function as CCR4 antagonists were discovered during the screening of our corporate compound libraries. Subsequent compound optimization elucidated the structure-activity relationships and led the identification of 2-(1,4'-bipiperidine-1'-yl)-N-cycloheptyl-6,7-dimethoxyquinazolin-4-amine 14a, which showed potent inhibition in the [(35)S]GTPgammaS-binding assay (IC(50)=18nM). This compound also inhibited the chemotaxis of human and mouse CCR4-expressing cells (IC(50)=140nM, 39nM).


Assuntos
Quinazolinas/síntese química , Quinazolinas/farmacologia , Receptores CCR4/antagonistas & inibidores , Animais , Quimiotaxia/efeitos dos fármacos , Guanosina 5'-O-(3-Tiotrifosfato)/metabolismo , Humanos , Camundongos , Relação Estrutura-Atividade
16.
Plant Cell Physiol ; 49(7): 1066-73, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18535009

RESUMO

NAD(P)H dehydrogenase (NDH) is a homolog of respiratory complex I and mediates one of the two pathways of cyclic electron flow around PSI (CEF I). Although 15 ndh subunits have been identified in the chloroplastic and nuclear genomes of higher plants, no electron accepter subunits have been identified to date. To identify the missing chloroplastic NDH subunits, we undertook an in silico approach based on co-expression analysis. In this report, we characterized the novel gene NDF6 (NDH-dependent flow 6; At1g18730) which encodes a protein that is essential for NDH activity. NDF6 has one transmembrane domain and is localized in the thylakoid membrane fraction. Homologous proteins of NDF6 were identified in the genomes of terrestrial plants; however, no homologs have been found in cyanobacteria, which are thought to be the origin of chloroplasts and have a minimal NDH complex unit. NDF6 is unstable in ndhB-impaired or disrupted mutants of higher plants in which the chloroplastic NDH complex is thought to be degraded. These results suggest that NDF6 is a novel subunit of chloroplastic NDH that was added to terrestrial plants during evolution.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Proteínas de Membrana/metabolismo , NADPH Desidrogenase/metabolismo , Tilacoides/enzimologia , Sequência de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/isolamento & purificação , DNA Bacteriano , Estabilidade Enzimática , Genes de Plantas , Proteínas de Membrana/química , Proteínas de Membrana/isolamento & purificação , Dados de Sequência Molecular , Mutagênese Insercional , Proteínas Mutantes/isolamento & purificação , Proteínas Mutantes/metabolismo , Mutação/genética , NADPH Desidrogenase/química , Fotossíntese , Transporte Proteico , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
17.
Mol Cells ; 25(2): 158-62, 2008 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-18414017

RESUMO

Recent molecular genetics studies have revealed that cyclic electron transport around photosystem I is essential for normal photosynthesis and growth of plants. Chloroplastic NAD(P)H dehydorgenase (NDH) complex, a homologue of the complex I in respiratory electron transport, is involved in one of two cyclic pathways. Recent studies on the function and structure of the NDH complex are reviewed.


Assuntos
Cloroplastos/enzimologia , NADPH Desidrogenase/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Cianobactérias/enzimologia , Transporte de Elétrons , NADPH Desidrogenase/química , Plantas/enzimologia
18.
Bioorg Med Chem ; 15(1): 403-12, 2007 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-17049248

RESUMO

3-{1-[(4-Fluorophenyl)sulfonyl]-1H-pyrazol-3-yl}-2-methylimidazo[1,2-a]pyridine, 2a, was discovered in our chemical library as a novel p110alpha inhibitor with an IC(50) of 0.67microM, through screening in a scintillation proximity assay. Optimization of the substituents of 2a increased the p110alpha inhibitory activity by more than 300-fold (2g: IC(50)=0.0018microM). Further structural modification of 2g afforded thiazole derivative 12, which has potent p110alpha inhibitory activity (IC(50) of 0.0028microM) and is highly selective for p110alpha over other PI3K isoforms. Compound 12 also inhibited serum-induced cell proliferation of A375 and HeLa cells in vitro with IC(50) values of 0.14microM and 0.21microM, respectively, and suppressed tumor growth by 37% in a mouse HeLa xenograft model when dosed intraperitoneally at 25mg/kg. These results suggest that selective p110alpha inhibitors may have potential as cancer therapeutic agents.


Assuntos
Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacologia , Piridinas/síntese química , Piridinas/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Injeções Intraperitoneais , Isoenzimas/antagonistas & inibidores , Camundongos , Estrutura Molecular , Inibidores de Proteínas Quinases/administração & dosagem , Piridinas/administração & dosagem , Estereoisomerismo , Relação Estrutura-Atividade , Fatores de Tempo , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Nihon Koshu Eisei Zasshi ; 52(11): 979-86, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16408483

RESUMO

We previously reported that the prevalence of elevated alanine aminotransferase (ALT) increases with accumulation of metabolic syndrome components, and a greater degree of involvement of aldehyde dehydrogenase 2 (ALDH2) than beta3-adrenergic receptor gene (beta3-AR) polymorphisms. The present study was designed to clarify the effect of aging, lifestyle and the two gene polymorphisms on the relationship between 4 components of the metabolic syndrome (obesity, hypertension, dyslipidemia and impaired glucose tolerance) and elevated ALT values in a subset of 73 out of 148 male workers who were 35 years of age in the baseline study and 40 years old in the present study. Study subjects completed questionnaires about drinking and smoking habits, and underwent urinalysis, physical examination and peripheral blood tests, blood chemistry, electrocardiogram and chest X-rays each year as required by Japanese law. Information from the questionnaires and physical examinations, including liver function tests, were compared with previously reported ALDH2 and beta3-AR genotypes for the 73 workers. Of the 73 workers studied, 14 (19%) demonstrated decrease in metabolic syndrome components, 39 (53%) demonstrated no change, and 20 (27%) demonstrated an increase. Ten workers (14%) showed liver dysfunction at age 35 and 20 workers (27%) at age 40. Fourteen workers were newly diagnosed as having liver dysfunction at their 40-year checkup, thus being associated with the BMI and an active ALDH2 genotype. Accumulation of components of the metabolic syndrome were associated with the presence of liver dysfunction at 35 years. In conclusion, these findings indicate that ALDH2 genotyping as well as lifestyle habits may be important factors in causing metabolic syndrome with liver dysfunction.


Assuntos
Alanina Transaminase/sangue , Aldeído Desidrogenase/genética , Estilo de Vida , Fígado/enzimologia , Síndrome Metabólica/etiologia , Saúde Ocupacional , Exame Físico , Polimorfismo Genético , Receptores Adrenérgicos beta 3/genética , Adulto , Fatores Etários , Envelhecimento/fisiologia , Aldeído-Desidrogenase Mitocondrial , Humanos , Masculino , Síndrome Metabólica/epidemiologia , Prevalência , Inquéritos e Questionários , Fatores de Tempo
20.
Nihon Koshu Eisei Zasshi ; 52(11): 987-93, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16408484

RESUMO

OBJECTIVE: It is well established that job stress is a leading cause of cardiovascular disease. The relationship with the metabolic syndrome, however, has received only limited attention. The present study was designed to investigate associations between change of the type of job and the prevalence of metabolic syndrome components from the aspect of on-the-job stress and alteration in life style. METHODS: Thirty-six male workers of the manufacturing department were transferred to the carsales department at the same automobile company in 1992 to 1993. These same workers were transferred back to the manufacturing department after two years. We compared the first health-check data before the transfer in 1992 (Term A), a second set of data two years after transfer in 1994-95 (Term B) and a third set of data two years following transfer back to the manufacturing department in 1996-1998 (Term C). The workers were requested to provide information about drinking and smoking habits, and answer Karasek's questionnaire and a simple stress questionnaire in order to clarify the possibility of job stress in occurrence of the metabolic syndrome, defined in terms of obesity, hypertension, dyslipidemia, and impaired glucose tolerance as components. RESULTS: Five workers had two or more components of the metabolic syndrome before the transfer to the car-sales department (Group I). One demonstrated improvement, three no change, and one increase in symptoms from A to B. Seven workers had more than two components after the transfer to car-sales department (Group II), and six of them exhibited decrease two years following transfer back to the manufacturing department. Five of them also showed elevated liver enzymes in serum with the appearance of the components, and three of them demonstrated recover. Three workers had two components of the metabolic syndrome only at time point C (Group III), while the remaining 21 workers had 0 to one component throughout the observation period (Group IV). Amount of drinking and smoking increased significantly when working in the sales department but these items returned to the previous values after rejoining manufacturing, though differences were not observed between workers with (Group II) and without (Group IV) components of the metabolic syndrome. Body mass index (BMI) and alanine aminotransferase (ALT) increased significantly when workers moved to the sales department and that was significant in Group II as compared to Group IV. Three components of Karasek's JCQ changed significantly during job transfer, though differences were not observed between the workers with (Group II) and without (Group IV) components of the metabolic syndrome. Logistic regression analysis with age, lifestyle, Karasek's JCQ, and ALT revealed that elevation of ALT value was associated with having two or more components of metabolic syndrome, while hours of sleep demonstrated an inverse association. CONCLUSION: Elevated ALT and reduction of sleep hours may be associated with development of the metabolic syndrome in workers who change their type of job.


Assuntos
Síndrome Metabólica/etiologia , Saúde Ocupacional , Estresse Psicológico/complicações , Trabalho/psicologia , Adulto , Fatores Etários , Índice de Massa Corporal , Antígenos CD13/sangue , Humanos , Estilo de Vida , Modelos Logísticos , Masculino , Síndrome Metabólica/epidemiologia , Prevalência , Privação do Sono/complicações , Estresse Psicológico/epidemiologia , Inquéritos e Questionários , Local de Trabalho
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...