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ANTI-TRYPANOSOMAL ACTIVITY OF 1,2,3,4,6-PENTA-O-GALLOYL-beta-D-GLUCOSE ISOLATED FROM Plectranthus barbatus Andrews (Lamiaceae)

Santos, Roberta T. dos; Hiramoto, Liliane L.; Lago, Joao Henrique G.; Sartorelli, Patricia; Tempone, Andre G.; Pinto, Erika G.; Lorenzi, Harri
Fonte: SOC BRASILEIRA QUIMICA; SAO PAULO Publicador: SOC BRASILEIRA QUIMICA; SAO PAULO
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.71319%
MeOH extract from the leaves of Plectranthus barbatus Andrews (Lamiaceae), showed in vitro anti-trypanosomal activity. The bioassay-guided fractionation resulted in the isolation of a gallic acid derivative, identified as 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG), after thorough NMR and MS spectral analysis. Finally, this compound was tested against trypomastigote forms of T. cruzi and displayed an EC50 value of 67 mu M, at least 6.6-fold more effective than the standard drug benznidazole. This is the first occurrence of PGG in the Plectranthus genus and the first anti-parasitic activity described for PGG in the literature.; FAPESP; CNPq; CAPES; PIBIC/UNIFESP

2,3,4,6-Tetra-O-(3-nitropropanoyl)-O-β-D-glucopyranoside, a new antimicrobial from the roots of Heteropteris aphrodisiaca

Roman Jr., Walter Antônio; Cardoso, Mara Lane Carvalho; Vilegas, Wagner; Nakamura, Celso Vataru; Dias Filho, Benedito Prado; De Mello, João Carlos Palazzo
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 543-545
Português
Relevância na Pesquisa
66.722397%
A new 2,3,4,6-tetra-O-(3-nitropropanoyl)-O-β-D-glucopyranoside anomer was isolated from the roots of Heteropteris aphrodisiaca and characterized by spectroscopic methods. Activity against Staphylococcus aureus, Bacillus subtilis, Candida albicans, C. parapsilosis, C. krusei, and C. tropicalis was demonstrated.

2,4,6 – tricloroanisol: validação do método de análise e estudos de adsorção e dessorção em rolhas de cortiça

Fonseca, Maria Filomena Paiva de
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Dissertação de Mestrado
Português
Relevância na Pesquisa
66.69621%
Dissertação de Mestrado em Enologia; A cortiça assume uma posição de destaque no contexto da economia portuguesa, pelo volume de exportações e pelo volume de empregabilidade associado. Neste contexto a Amorim & Irmãos, S.A, tem um papel determinante na procura de inovação e qualidade dos seus processos e métodos, melhorando assim a qualidade dos produtos. Na primeira parte deste projeto de investigação, foi realizada a validação do método analítico de 2,4,6-tricloroanisol, por cromatografia em fase gasosa com o objetivo de assegurar a fiabilidade dos resultados e de verificar o desempenho dos equipamentos, estudando os seguintes parâmetros: gama de trabalho, linearidade, limiares analíticos, precisão, repetibilidade, precisão intermédia, exatidão e robustez. Em todas as análises foram usados os métodos SPME/GC/ECD e SPME/GC/MS. A segunda parte do projeto foi destinada, ao estudo da cinética de migração do binómio vinho/rolha e rolha/vinho, tendo como objetivo conhecer a dualidade de transferência do 2,4,6-tricloroanisol podendo assim quantificá-la. Este estudo, reveste-se da maior importância para a empresa, pois permite o esclarecimento da origem da contaminação por 2,4,6-tricloroanisol em garrafas de vinho...

Método para deteção de 2,4,6-TCA por contaminação de gases halogenados de uma superfície emissora de iões positivos

Couto, Isabel Amaral
Fonte: Faculdade de Ciências e Tecnologia Publicador: Faculdade de Ciências e Tecnologia
Tipo: Dissertação de Mestrado
Publicado em //2013 Português
Relevância na Pesquisa
76.45101%
Dissertação para obtenção do Grau de Mestre em Engenharia Física; A contaminação do vinho que produz cheiro a “mofo” é um problema que afeta a indústria corticeira. O principal agente contaminante é 2,4,6-TCA que, em solução alcoólica, o limiar de deteção humana é da ordem de 5 ng/L. As características da rolha de cortiça tornam difícil a sua descontaminação e os métodos de deteção disponíveis atualmente não permitem a aplicação na indústria. Neste trabalho, é explorada a deteção de gases halogenados pela formação de uma dupla camada na superfície de um emissor de iões alcalinos. Os iões alcalinos são emitidos por ionização superficial. A corrente iónica alcalina em vácuo segue, nas condições experimentais, a lei de Child-Langmuir e a função de trabalho é calculada num determinado intervalo de temperatura pela equação de Saha-Langmuir. Embora os resultados tenham tido um sucesso limitado, verificou-se que a introdução de clorofórmio (como exemplo de gás halogenado) produziu um aumento da corrente iónica que depende da temperatura e da pressão. A recuperação da corrente foi feita ao aquecer o emissor até cerca de 1200K durante alguns minutos. O campo eléctrico de extração que foi aplicado variou entre 30V/cm e 135V/cm em regime contínuo e a temperatura variou entre 800K e 1200K.

Anti-trypanosomal activity of 1,2,3,4,6-penta-O-galloyl-β -D-glucose isolated from Plectranthus barbatus Andrews (Lamiaceae)

Santos,Roberta T. dos; Hiramoto,Liliane L.; Lago,João Henrique G.; Sartorelli,Patrícia; Tempone,André G.; Pinto,Erika G.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
Relevância na Pesquisa
66.71319%
MeOH extract from the leaves of Plectranthus barbatus Andrews (Lamiaceae), showed in vitro anti-trypanosomal activity. The bioassay-guided fractionation resulted in the isolation of a gallic acid derivative, identified as 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), after thorough NMR and MS spectral analysis. Finally, this compound was tested against trypomastigote forms of T. cruzi and displayed an EC50 value of 67 µM, at least 6.6-fold more effective than the standard drug benznidazole. This is the first occurrence of PGG in the Plectranthus genus and the first anti-parasitic activity described for PGG in the literature.

A micromethod for quantitation of debrisoquine and 4-hydroxydebrisoquine in urine by liquid chromatography

Pereira,V.A.; Auler Jr.,J.O.; Carmona,M.J.; Mateus,F.H.; Lanchote,V.L.; Breimer,D.D.; Santos,S.R.C.J.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2000 Português
Relevância na Pesquisa
56.996235%
We describe a new simple, selective and sensitive micromethod based on HPLC and fluorescence detection to measure debrisoquine (D) and 4-hydroxydebrisoquine (4-OHD) in urine for the investigation of xenobiotic metabolism by debrisoquine hydroxylase (CYP2D6). Four hundred µl of urine was required for the analysis of D and 4-OHD. Peaks were eluted at 8.3 min (4-OHD), 14.0 min (D) and 16.6 min for the internal standard, metoprolol (20 µg/ml). The 5-µm CN-reverse-phase column (Shimpack, 250 x 4.6 mm) was eluted with a mobile phase consisting of 0.25 M acetate buffer, pH 5.0, and acetonitrile (9:1, v/v) at 0.7 ml/min with detection at lexcitation = 210 nm and lemission = 290 nm. The method, validated on the basis of measurements of spiked urine, presented 3 ng/ml (D) and 6 ng/ml (4-OHD) sensitivity, 390-6240 ng/ml (D) and 750-12000 ng/ml (4-OHD) linearity, and 5.7/8.2% (D) and 5.3/8.2% (4-OHD) intra/interassay precision. The method was validated using urine of a healthy Caucasian volunteer who received one 10-mg tablet of Declinax®, po, in the morning after an overnight fast. Urine samples (diuresis of 4 or 6 h) were collected from zero to 24 h. The urinary excretion of D and 4-OHD, Fel (0-24 h), i.e., fraction of dose administered and excreted into urine...

Isolation from Estuarine Sediments of a Desulfovibrio Strain Which Can Grow on Lactate Coupled to the Reductive Dehalogenation of 2,4,6-Tribromophenol

Boyle, Alfred W.; Phelps, Craig D.; Young, L. Y.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /03/1999 Português
Relevância na Pesquisa
56.700005%
Strain TBP-1, an anaerobic bacterium capable of reductively dehalogenating 2,4,6-tribromophenol to phenol, was isolated from estuarine sediments of the Arthur Kill in the New York/New Jersey harbor. It is a gram-negative, motile, vibrio-shaped, obligate anaerobe which grows on lactate, pyruvate, hydrogen, and fumarate when provided sulfate as an electron acceptor. The organism accumulates acetate when grown on lactate and sulfate, contains desulfoviridin, and will not grow in the absence of NaCl. It will not utilize acetate, succinate, propionate, or butyrate for growth via sulfate reduction. When supplied with lactate as an electron donor, strain TBP-1 will utilize sulfate, sulfite, sulfur, and thiosulfate for growth but not nitrate, fumarate, or acrylate. This organism debrominates 2-, 4-, 2,4-, 2,6-, and 2,4,6-bromophenol but not 3- or 2,3-bromophenol or monobrominated benzoates. It will not dehalogenate monochlorinated, fluorinated, or iodinated phenols or chlorinated benzoates. Together with its physiological characteristics, its 16S rRNA gene sequence places it in the genus Desulfovibrio. The average growth yield of strain TBP-1 grown on a defined medium supplemented with lactate and 2,4,6-bromophenol is 3.71 mg of protein/mmol of phenol produced...

2-pyrone-4,6-dicarboxylic acid, a catabolite of gallic acids in Pseudomonas species.

Kersten, P J; Dagley, S; Whittaker, J W; Arciero, D M; Lipscomb, J D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1982 Português
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56.81604%
2-Pyrone-4,6-dicarboxylate hydrolase was purified from 4-hydroxybenzoate-grown Pseudomonas testosteroni. Gel filtration and electrophoretic measurements indicated that the preparation was homogeneous and gave a molecular weight of 37,200 for the single subunit of the enzyme. Hydrolytic activity was dependent upon a functioning sulfhydryl group(s) and was freely reversible; the equilibrium position was dependent upon pH, with equimolar amounts of pyrone and open-chain form present at pH 7.9. Since the hydrolase was strongly induced when the nonfluorescent organisms P. testosteroni and P. acidovorans grew with 4-hydroxybenzoate, it is suggested that 2-pyrone-4,6-dicarboxylate is a normal intermediate in the meta fission degradative pathway of protocatechuate. Laboratory strains of fluorescent pseudomonads did not metabolize 2-pyrone-4,6-dicarboxylate, but a strain of P. putida was isolated from soil that utilized this compound for growth; the hydrolase was then induced, but it was absent from extracts of 4-hydroxybenzoate-grown cells that readily catabolized protocatechuate by ortho fission reactions. 2-Pyrone-4,6-dicarboxylic acid was the major product formed when gallic acid was oxidized by purified protocatechuate 3,4-dioxygenase. Protocatechuate 4...

Distinct and nonoverlapping roles for pRB and cyclin D:cyclin-dependent kinases 4/6 activity in melanocyte survival

Yu, Benjamin D.; Becker-Hapak, Michelle; Snyder, Eric L.; Vooijs, Marc; Denicourt, Catherine; Dowdy, Steven F.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.73546%
Deregulation of the p16INK4a–cyclin D:cyclin-dependent kinases (cdk) 4/6 –retinoblastoma (pRB) pathway is a common paradigm in the oncogenic transformation of human cells and suggests that this pathway functions linearly in malignant transformation. However, it is not understood why p16INK4a and cyclin D:cdk4/6 mutations are disproportionately more common than the rare genetic event of RB inactivation in human malignancies such as melanoma. To better understand how these complexes contribute to altered tissue homeostasis, we blocked cdk4/6 activation and acutely inactivated Rb by conditional mutagenesis during mouse hair follicle cycling. Inhibition of cdk4/6 in the skin by subcutaneous administration of a membrane-transducible TAT-p16INK4a protein completely blocked hair follicle growth and differentiation. In contrast, acute disruption of Rb in the skin of homozygous RbLoxP/LoxP mice via subcutaneous administration of TAT-Cre recombinase failed to affect hair growth. However, loss of Rb resulted in severe depigmentation of hair follicles. Further analysis of follicular melanocytes in vivo and in primary cell culture demonstrated that pRB plays a cell-autonomous role in melanocyte survival. Moreover, functional inactivation of all three Rb family members (Rb...

Partial reactions of d-glucose 6-phosphate–1 l-myoinositol 1-phosphate cyclase

Barnett, J. E. G.; Rasheed, A.; Corina, D. L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1973 Português
Relevância na Pesquisa
56.86062%
After removal of tightly bound NAD+ by using charcoal, a preparation of d-glucose 6-phosphate–1 l-myoinositol 1-phosphate cyclase catalysed the reduction of 5-keto-d-glucitol 6-phosphate and 5-keto-d-glucose 6-phosphate by [4-3H]NADH to give [5-3H]-glucitol 6-phosphate and [5-3H]glucose 6-phosphate respectively. The position of the tritium atom in the latter was shown by degradation. Both enzyme-catalysed reductions were strongly inhibited by 2-deoxy-d-glucose 6-phosphate, a powerful competitive inhibitor of inositol cyclase. The charcoal-treated enzyme preparation also converted 5-keto-d-glucose 6-phosphate into [3H]myoinositol 1-phosphate in the presence of [4-3H]NADH, but less effectively. These partial reactions of inositol cyclase are interpreted as providing strong evidence for the formation of 5-keto-d-glucose 6-phosphate as an enzyme-bound intermediate in the conversion of d-glucose 6-phosphate into 1 l-myoinositol 1-phosphate. The enzyme was partially inactivated by NaBH4 in the presence of NAD+. Glucose 6-phosphate did not increase the inactivation, and there was no inactivation in the absence of NAD+. There was no evidence for Schiff base formation during the cyclization. d-Glucitol 6-phosphate (l-sorbitol 1-phosphate) was a good inhibitor of the overall reaction. It did not inactivate the enzyme. The apparent molecular weight of inositol cyclase as determined by Sephadex chromatography was 2.15×105.

Proteoglycans contain a 4.6 A repeat in muscular dystrophy corneas: x-ray diffraction evidence.

Quantock, A J; Klintworth, G K; Schanzlin, D J; Capel, M S; Lenz, M E; Thonar, E J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1996 Português
Relevância na Pesquisa
56.682905%
Synchrotron x-ray diffraction patterns from macular corneal dystrophy (MCD) corneas contain an unusual reflection that arises because of an undefined ultrastructure with a periodic repeat in the region of 4.6 A. In this study, we compared with wide-angle x-ray diffraction patterns obtained from four normal human corneas and four MCD corneas. Moreover, portions of two of the MCD corneas were pretreated with a specific glycosidase to shed light on the origin of the 4.6 A reflection. None of the normal corneas produced an x-ray reflection in the region of 4.6 A, whereas all four of the MCD corneas did (MCD type I at 4.65 A and 4.63 A, MCD type II at 4.63 A and 4.67 A). This reflection was diminished after incubation of the MCD tissues with either chondroitinase ABC or N-glycanase. The findings indicate that glycosaminoglycans or proteoglycans contribute to the unusual MCD x-ray reflection and hence most likely contain a periodic 4.6 A ultrastructure. Furthermore, the results imply that periodic 4.6 A MCD ultrastructures reside in either intact, unsulfated lumican molecules and regions of the CS/DS-containing molecules or in a region of a hybrid macromolecular aggregate formed by the interaction of the two molecules.

Effect of Incubation Temperature on the Route of Microbial Reductive Dechlorination of 2,3,4,6-Tetrachlorobiphenyl in Polychlorinated Biphenyl (PCB)-Contaminated and PCB-Free Freshwater Sediments

Wu, Q.; Bedard, D. L.; Wiegel, J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1997 Português
Relevância na Pesquisa
56.81468%
We studied the influence of temperature (4 to 66(deg)C) on the microbial dechlorination of 2,3,4,6-tetrachlorobiphenyl (2,3,4,6-CB) incubated for 1 year in anaerobic sediments from Woods Pond in Lenox, Mass., and Sandy Creek Nature Center Pond (SCNC) in Athens, Ga. Seven discrete dechlorination reactions were observed, four of which occurred in both sediments. These were 2,3,4,6-CB (symbl) 2,4,6-CB, 2,3,4,6-CB (symbl) 2,3,6-CB, 2,4,6-CB (symbl) 2,6-CB, and 2,3,6-CB (symbl) 2,6-CB. Three additional reactions occurred only in Woods Pond sediment. These were 2,4,6-CB (symbl) 2,4-CB, 2,4-CB (symbl) 2-CB, and 2,4-CB (symbl) 4-CB. The dechlorination reactions exhibited at least four different temperature dependencies in SCNC sediment and at least six in Woods Pond sediment. We attribute the discrete dechlorination reactions to different polychlorinated biphenyl (PCB)-dechlorinating microorganisms with distinct specificities. Temperature influenced the timing and the relative predominance of parallel pathways of dechlorination, i.e., meta versus para dechlorination of 2,3,4,6-CB and ortho versus para dechlorination of 2,4,6-CB and 2,4-CB. meta dechlorination of 2,3,4,6-CB to 2,4,6-CB dominated at all tested temperatures except at 18 and 34(deg)C...

Development and Binding Mode Assessment of N-[4-[2-propyn-1-yl[(6S)-4,6,7,8-tetrahydro-2-(hydroxymethyl)-4-oxo-3H-cyclopenta[g]quinazolin-6-yl]amino]benzoyl]-L-γ-glutamyl-D-glutamic acid (BGC 945), a Novel Thymidylate Synthase Inhibitor that Targets Tumor Cells

Tochowicz, Anna; Dalziel, Sean; Eidam, Oliv; O’Connell, Joseph D.; Griner, Sarah; Finer-Moore, Janet S.; Stroud, Robert M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.769683%
N-[4-[2-propyn-1-yl[(6S)-4,6,7,8-tetrahydro-2-(hydroxymethyl)-4-oxo-3H-cyclopenta[g]quinazolin-6-yl]amino]benzoyl]-L-γ-glutamyl-D-glutamic acid 1 (BGC 945, now known as ONX 0801), is a small molecule thymidylate synthase (TS) inhibitor discovered at the Institute of Cancer Research in London. It is licensed by Onyx Pharmaceuticals and is in Phase 1 clinical studies. It is a novel antifolate drug resembling TS inhibitors plevitrexed and raltitrexed that combines enzymatic inhibition of thymidylate synthase with α-folate receptor-mediated targeting of tumor cells. Thus, it has potential for efficacy with lower toxicity due to selective intracellular accumulation through α-folate receptor (α-FR) transport. The α-FR, a cell-surface receptor glycoprotein, which is over expressed mainly in ovarian and lung cancer tumors, has an affinity for 1 similar to that for its natural ligand, folic acid. This study describes a novel synthesis of 1, an X-ray crystal structure of its complex with Escherichia coli TS and 2’-deoxyuridine-5’-monophosphate, and a model for a similar complex with human TS.

Quantificação de resíduos do 2,4 D em amostras de água por cromatografia a gás.

SANTOS, A.C.; LANCHOTE, V.L.; BONATO, P.S.; QUEIROZ, R.H.C.; SANTOS, N.A.G.; CERDEIRA, A. L.; CARVALHO, D.
Fonte: Revista Brasileira de Toxicologia, v.6, 1993. Suplemento. Publicador: Revista Brasileira de Toxicologia, v.6, 1993. Suplemento.
Tipo: Artigo em periódico indexado (ALICE) Formato: n.p.
Português
Relevância na Pesquisa
56.67573%
O 2,4 D apresenta moderada solubilidade em água, media solubilidade nos solos e portanto constitui um herbicida com potencial risco de contaminação das águas. De acordo com os padrões de qualidade da água, estabelecidos pelos Estados Unidos e Canada, a Concentração Máxima Tolerada de 2,4 D e de 100 ug/l. Com o objetivo de implantar um programa de monitoramento das águas das regiões de Ribeirão Preto, Serrana e Guaíra, foi desenvolvido um método de analise do 2,4 D em água utilizando a cromatografia em fase gasosa com detector por captura de elétrons. UM volume de 100 ml de água, hidrolisado durante 1 hora em meio alcalino, foi acidificado e extraido com três porcões de 5 ml de diclorometano. Após evaporação das fases orgânicas, o 2,4 D e padrão interno foram esterificados com HCl 0,5 N em metanol e extraídos com tolueno. A separação foi efetuada em coluna de vidro, recheada com 2% de SP 2110 e 1% de SP 2510 em Supelcoport, operando com 35 ml/min de nitrogênio ultra-puro. A recuperação do 2,4 D adicionado a amostras de água foi 66%. O limite de quantificação do método foi 0,4 ug/l com linearidade experimentada ate 8,0 ug/l. A repetibilidade do método, avaliada através da analise intra e inter ensaios do 2...

Quantificação de resíduos de 2,4 D em amostras de água por cromatografia liquida de alta eficiencia.

SANTILI, M.B.; LANCHOTE, V.L.; BONATO, P.S.; SANTOS, A.C.; QUEIROZ, R.N.C.; CERDEIRA, A. L.; CARVALHO, D.
Fonte: Revista Brasileira de Toxicologia, v.6, 1993. Suplemento. Publicador: Revista Brasileira de Toxicologia, v.6, 1993. Suplemento.
Tipo: Artigo em periódico indexado (ALICE) Formato: n.p.
Português
Relevância na Pesquisa
56.84423%
Os riscos de saudê do homem com a contaminação das aguas por resíduos de herbicidas são decorrentes da exposição diária a baixas concentrações. Considerando que a qualidade da água potável so pode ser assegurada através do estabelecimento de programas de monitoramento, foi desenvolvido um método para a analise de resíduos do herbicida 2,4 D utilizando a cromatografia liquida de alta eficiência com detecção por ultra-violeta a 284 nm. Apos hidrolise em meio alcalino, amostras de 100 ml de água foram adicionadas do padrão interno (clobazans) e extraídas em meio acido com três porcões de 5,0 ml de diclorometano. As fases orgânicas foram reunidas e evaporadas ate a secura sob corrente de gás inerte. Os resíduos foram retomados com 35 ul da fase móvel, constituída por metanol-tampão acetato 0,25 N pH 3,5 (6:4, v/v), e analisados com coluna Licnrocart (Merck), 125 - 4 mm, RP-8 (partículas de 5 um). O padrão interno e o 2,4 D foram eluídos, respectivamente, com tempos de retenção de 2,0 e 3,4 min. A curva de calibração foi construída no intervalo 0,4 - 1,6 ug/l com coeficientes de variação inferiores a 10%. O método apresenta sensibilidade compatível com a concentração máxima tolerável de 2,4 D na agua...

Ca2(+)-stimulatable and protein kinase C-inhibitable accumulation of inositol 1,3,4,6-tetrakisphosphate in human platelets.

King, W G; Downes, C P; Prestwich, G D; Rittenhouse, S E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/08/1990 Português
Relevância na Pesquisa
56.956616%
Thrombin-stimulated (10 s) human platelets produce Ins(1,4,5)P3 and an additional inositol trisphosphate (InsP3), in approximately a 1:20 ratio. The major InsP3 co-migrates with Ins(1,3,4)P3 on strong-anion-exchange h.p.l.c. To identify this species unequivocally, we treated putative Ins(1,3,4)P3 obtained from thrombin-stimulated myo-[3H]inositol-labelled platelets with NaIO4/NaBH4 or 4-phosphomonoesterase. The products indicate that the major InsP3 is at least 90% D-Ins(1,3,4)P3. D-[3H]Ins(1,3,4)P3 added to saponin-permeabilized platelets is hydrolysed to an InsP2 (7.8%) and phosphorylated by a kinase to yield an inositol polyphosphate (0.9%) in 5 min. The phosphorylation product co-migrates with Ins(1,3,4,6)P4 on Partisphere WAX h.p.l.c. Under similar conditions, L-[3H]Ins(1,3,4)P3 is dephosphorylated but not phosphorylated. Relative phosphatase:kinase ratios are 8.7:1 (Vmax. values) and 0.86:1 (Km values) with respect to D-Ins(1,3,4)P3. The kinase activity is predominantly cytosolic (96.8% of total activity) in freeze-thaw-disrupted platelets, and the accumulation of its product is Ca2(+)-dependent. The activity is identified as a 6-kinase on the basis of its product's insensitivity to 5-phosphomonoesterase, resistance to periodate oxidation and co-migration with standard Ins(1...

Kaluza-Klein gauge and minimal integrable extension of OSp(4|6)/(SO(1,3) x U(3)) sigma-model

Uvarov, D. V.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.8988%
Basing upon experience from performing double-dimensional reduction of the D=11 supermembrane on AdS_4 x S^7 background to Type IIA superstring on AdS_4 x CP^3 we introduce Kaluza-Klein (partial) kappa-symmetry gauge as a vanishing condition of the contribution to the D=11 supervielbein components tangent to D=10 space-time proportional to the differential of the coordinate parametrizing compact 11-th space-time dimension, that is identified with the supermembrane world-volume compact dimension. For AdS_4 x S^7 supermembrane Kaluza-Klein gauge removes half Grassmann coordinates associated with 8 space-time supersymmetries, broken by the AdS_4 x CP^3 superbackground, by imposing D=3 (anti-)Majorana condition on them. The consideration relies on the realization of osp(4|8) isometry superalgebra of the AdS_4 x S^7 superbackground as D=3 N=8 superconformal algebra. Requiring further vanishing of the D=10 dilaton leaves in the sector of broken supersymmetries just two Grassmann coordinates organized into D=3 (anti-)Majorana spinor that defines minimal SL(2,R)-covariant extension of the OSp(4|6)/(SO(1,3)x U(3)) sigma-model. Among 4 possibilities of such a minimal extension we consider in detail one, that corresponds to picking out D=3 Majorana coordinate related to broken Poincare supersymmetry...

Tadpole versus anomaly cancellation in D=4,6 compact IIB orientifolds

Aldazabal, G.; Badagnani, D.; Ibanez, L. E.; Uranga, A. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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It is often stated in the literature concerning D=4,6 compact Type IIB orientifolds that tadpole cancellation conditions i) uniquely fix the gauge group (up to Wilson lines and/or moving of branes) and ii) are equivalent to gauge anomaly cancellation. We study the relationship between tadpole and anomaly cancellation conditions and qualify both statements. In general the tadpole cancellation conditions imply gauge anomaly cancellation but are stronger than the latter conditions in D=4, N=1 orientifolds. We also find that tadpole cancellation conditions in Z_N D=4,6 compact orientifolds do not completely fix the gauge group and we provide new solutions different from those previously reported in the literature.; Comment: 28 pages, Latex. Minor corrections, updated references

BPS preons and higher spin theory in D=4, 6, 10

Bandos, Igor A.; de Azcarraga, Jose A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/12/2006 Português
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We briefly review here the notion of BPS preons, the hypothetical constituents of M-theory, emphasizing its generalization to arbitrary dimensions D and its relation to higher spin theories in D=4,6 and 10.; Comment: Invited contribution delivered at the XXII Max Born Symposium, Wroclaw (Poland), September 27-29, 2006. 8 pages, plain latex, no figures

Bioremediation of 2,4,6-trinitrotoluene by bacterial nitroreductase expressing transgenic aspen

Van Dillewijn, Pieter; Couselo, José L.; Corredoira, Elena; Delgado Huertas, Antonio; Wittich, Rolf-Michael; Ballester, Antonio; Ramos, Juan L.
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 295796 bytes; application/pdf
Português
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6 pages, 5 figures.-- PMID: 18939578 [PubMed].-- Supporting information (6 pages) available at: http://pubs.acs.org/doi/suppl/10.1021/es801231w/suppl_file/es801231w_si_001.pdf; Printed version published on Oct 1, 2008.; Trees belonging to the genus Populus are often used for phytoremediation due to their deep root formation, fast growth and high transpiration rates. Here, we study the capacity of transgenic hybrid aspen (Populus tremula x tremuloides var. Etropole) which expresses the bacterial nitroreductase gene, pnrA, to tolerate and take-up greater amounts of the toxic and recalcitrant explosive, 2,4,6-trinitrotoluene (TNT) from contaminated waters and soil. Transgenic aspen tolerate up to 57 mg TNT/L in hydroponic media and more than 1000 mg TNT/ kg soil, whereas the parental aspen could not endure in hydroponic culture with more than 11 mg TNT/L or soil with more than 500 mg TNT/kg. Likewise, the phytotoxicological limit for transgenic plants to a constant concentration of TNT was 20 mg TNT/L while wild-type plants only tolerated 10 mg TNT/L. Transgenic plants also showed improved uptake of TNT over wild-type plants when the original TNT concentration was above 35 mg TNT/L in liquid media or 750 mg TNT/kg in soil. Assays with C-13-labeled TNT show rapid adsorption of TNT to the root surface followed by a slower entrance rate into the plant. Most of the C-13-carbon from the labeled TNT taken up by the plant (> 95%) remains in the root with little translocation to the stem. Altogether...