995 resultados para 19-191
Resumo:
Biotransformation of 3 beta-acetoxy-19-hydroxycholest-5-ene (19-HCA, 6 g) by Moraxella sp. was studied. Estrone (712 mg) was the major metabolite formed. Minor metabolites identified were 5 alpha-androst-1-en-19-ol-3,17-dione (33 mg), androst-4-en-19-ol-3,17-dione (58 mg), androst-4-en-9 alpha,19-diol-3,17-dione (12 mg), and androstan-19-ol-3,17-dione (1 mg). Acidic metabolites were not formed. Time course experiments on the fermentation of 19-HCA indicated that androst-4-en-19-ol-3,17-dione was the major metabolite formed during the early stages of incubation. However with continuing fermentation its level dropped, with a concomitant increase in estrone. Fermentation of 19-HCA in the presence of specific inhibitors or performing the fermentation for a shorter period (48 h) did not result in the formation of acidic metabolites. Resting-cell experiments carried out with 19-HCA (200 mg) in the presence of alpha,alpha'-bipyridyl led to the isolation of three additional metabolites, viz., cholestan-19-ol-3-one (2 mg), cholest-4-en-19-ol-3-one (10 mg), and cholest-5-en-3 beta,19-diol (12 mg). Similar results were also obtained when n-propanol was used instead of alpha,alpha'-bipyridyl. Resting cells grown on 19-HCA readily converted both 5 alpha-androst-1-en-19-ol-3,17-dione and androst-4-en-19-ol-3,17-dione into estrone. Partially purified 1,2-dehydrogenase from steroid-induced Moraxella cells transformed androst-4-en-19-ol-3,17-dione into estrone and formaldehyde in the presence of phenazine methosulfate, an artificial electron acceptor. These results suggest that the degradation of the hydrocarbon side chain of 19-HCA does not proceed via C-22 phenolic acid intermediates and complete removal of the C-17 side chain takes place prior to the aromatization of the A ring in estrone. The mode of degradation of the sterol side chain appears to be through the fission of the C-17-C-20 bond. On the basis of these observations, a new pathway for the formation of estrone from 19-HCA in Moraxella sp. has been proposed.
Resumo:
C19H26O4, M(r) = 318.41, orthorhombic, P2(1)2(1)2(1), a = 10.591 (1), b = 11.133 (1), c = 13.657 (2) angstrom, V = 1610.29 angstrom 3, Z = 4, D(m) (flotation in KI) = 1.301, D(x) = 1.313 g cm-3, Mo K-alpha, lambda = 0.7107 angstrom, mu = 0.85 cm-1, F(000) = 688, T = 293 K, R = 0.057 for 1253 significant reflections. The A ring is disordered with atoms C(2) and O(19) occupying two possible sites. The molecules are held together by a hydrogen bond [O(9)...O(17) = 2.89 angstrom].
Resumo:
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorodecyl 1,10-ditosylate and its precursors were synthesized and characterized by H-1- and F-19-NMR spectroscopic methods and X-ray crystallography. These compounds are building blocks for the syntheses of the surfactants containing polyperfluoromethylene spacer. The molecule has extended all-trans conformation with molecular symmetry (1) over bar (C-i). There is a reasonably strong C-H ... O interaction in the crystal and there are two F ... F intermolecular contact distances less than the sum of van der Waals radii. (C) 1999 Elsevier Science B.V. All rights reserved.
Resumo:
Chromatin immunoprecipitation identified 191 binding sites of Mycobacterium tuberculosis cAMP receptor protein (CRPMt) at endogenous expression levels using a specific alpha-CRPMt antibody. Under these native conditions an equal distribution between intragenic and intergenic locations was observed. CRPMt binding overlapped a palindromic consensus sequence. Analysis by RNA sequencing revealed widespread changes in transcriptional profile in a mutant strain lacking CRPMt during exponential growth, and in response to nutrient starvation. Differential expression of genes with a CRPMt-binding site represented only a minor portion of this transcriptional reprogramming with similar to 19% of those representing transcriptional regulators potentially controlled by CRPMt. The subset of genes that are differentially expressed in the deletion mutant under both culture conditions conformed to a pattern resembling canonical CRP regulation in Escherichia coli, with binding close to the transcriptional start site associated with repression and upstream binding with activation. CRPMt can function as a classical transcription factor in M. tuberculosis, though this occurs at only a subset of CRPMt-binding sites.
Resumo:
Here, we show the binding results of a leguminosae lectin, winged bean basic agglutinin (WBA I) to N-trifluoroacetylgalactosamine (NTFAGalN), methyl-alpha-N-trifluoroacetylgalactosamine (Me alpha NTFAGalN) and methyl-beta-tifluoroacetylgalactosamine (Me beta NTFAGalN) using (19) F NMR spectroscopy. No chemical shift difference between the free and bound states for NTFAGalN and Me beta NTFAGalN, and 0.01-ppm chemical shift change for Me alpha NTFAGalN, demonstrate that the Me alpha NTFAGalN has a sufficiently long residence time on the protein binding site as compared to Me beta NTFAGalN and the free anomers of NTFAGalN. The sugar anomers were found in slow exchange with the binding site of agglutinin. Consequently, we obtained their binding parameters to the protein using line shape analyses. Aforementioned analyses of the activation parameters for the interactions of these saccharides indicate that the binding of alpha and beta anomers of NTFAGalN and Me alpha NTFAGalN is controlled enthalpically, while that of Me beta NTFAGalN is controlled entropically. This asserts the sterically constrained nature of the interaction of the Me beta NTFAGalN with WBA I. These studies thus highlight a significant role of the conformation of the monosaccharide ligands for their recognition by WBA I.
Resumo:
Most often the measurement of VHF from the conventional 1D H-1 NMR spectrum is severely hindered consequent to similar magnitudes of JHF and JHH couplings and the spectral multiplicity pattern. The present study reports a new 1D NMR technique based on real time spin edition, which removes all JHF and JHH while retaining only VHF of a chosen fluorine. The obtained spectrum is significantly simplified and permits straightforward determination of all possible VHF values of a chosen fluorine. Due to one dimensional nature, the method is much faster compared to 2D GET-SERF by 1-2 orders of magnitude. (C) 2015 Elsevier B.V. All rights reserved.
Resumo:
We formulate the problem of detecting the constituent instruments in a polyphonic music piece as a joint decoding problem. From monophonic data, parametric Gaussian Mixture Hidden Markov Models (GM-HMM) are obtained for each instrument. We propose a method to use the above models in a factorial framework, termed as Factorial GM-HMM (F-GM-HMM). The states are jointly inferred to explain the evolution of each instrument in the mixture observation sequence. The dependencies are decoupled using variational inference technique. We show that the joint time evolution of all instruments' states can be captured using F-GM-HMM. We compare performance of proposed method with that of Student's-t mixture model (tMM) and GM-HMM in an existing latent variable framework. Experiments on two to five polyphony with 8 instrument models trained on the RWC dataset, tested on RWC and TRIOS datasets show that F-GM-HMM gives an advantage over the other considered models in segments containing co-occurring instruments.
Resumo:
La Constitución Nacional reconoce un orden de conducta instituido por Dios y otro instituido por el Estado… el débito legal debe resultar conforme al débito moral. Si así no fuera, cualquier imposición del legislador no sería derecho sino un acto de violencia desnaturalizando el poder que el Estado tiene de reforzar con débito eventualmente coercible obligaciones emergentes de la virtud de la justicia. En este trabajo nos ocuparemos de la relación entre ley moral natural y la ley positiva humana a partir de las consideraciones que Arturo Enrique Sampay2 formula en su obra, La filosofía jurídica del Artículo 19 de la Constitución Nacional3. Sampay desarrolla el tópico principalmente con la inspiración de la doctrina de Tomás de Aquino.
Resumo:
Contenido: Filosofía y originalidad / La Dirección – La idea de posible y el sentido de la existencia : génesis de esta idea / André Marc – Carácter existencial de la demostración de la existencia de Dios / Octavio N. Derisi – La naturaleza en la ciencia físico-matemática / Raimundo Paniker – Razones seminales y formas substanciales : agustinismo y tomismo / F. J. Thonnard – Notas y comentarios -- Bibliografía
Resumo:
Contenido: Editorial – Cum o Vrea Domnul. “Como Dios quiera” : ¿cómo entiende el rumano la sumisión a la voluntad de Dios? / Ioan Dan – Algunas cuestiones éticas y penales de las modernas técnicas biomédicas / Guillermo Jorge Yacobucci – El racionalismo moderno : configuración y proyecciones / Bernardino Bravo Lira – El pensamiento político en orígenes de Alejandría / Néstor Daniel Villa – El proceso penal de menores / Miguel Ángel Madariaga – Documentos -- Recensiones
Resumo:
Contenido: Las “gentiles casas” del libro de Pero Tafur / Sofía Carrizo Rueda – Una lectura de los “Cuatro cuartetos” e T. S. Eliot / Inés de Cassagne – La noción de función en las ciencias del lenguaje / Hugo Edgardo Lombardini – Los “Borges” del Fervor / Luis Martínez Cuitiño – El soneto primero de Garcilaso como afirmación doctrinaria / Graciela Maturo – Los símbolos de la culpa en “Cartas de mamá” / Graciela Pucciarelli de Colantonio – La anotación de la Soledad I (vv. 883-957) / Liliana Silvia Serviano – Un planto español para Roldán / Lía Noemí Uriarte Rebaudi – Notas – Reseñas bibliográficas
Resumo:
El rasgo sobresaliente de nuestra situación contemporánea consiste en que ésta se halla penetrada –de una manera cada vez más amplia y más profunda– por el impacto de las diversas tecnologías y, en relación con el interés de nuestro tema, por las tecnologías biomédicas. En esta ocasión quisiéramos iniciar nuestra reflexión señalando el antecedente prestigioso y hondamente significativo de la cuestión del hombre en el pensamiento trágico de Sófocles, en su tragedia Antígona, y prolongar esta reflexión en el examen de dos trabajos contemporáneos y convergentes en su preocupación filosófica y humanística escritos –en dos momentos históricos diversos– por: Günther Anders, en lengua alemana, traducido después al español y, finalmente, José Ignacio Murillo, en español. Se trata aquí de exponer lo esencial de los trabajos de ambos estudiosos citados a fin de iluminar el tema de nuestra presentación. Este hecho nos hace inmediatamente deudores de sus mejores ideas y de su peculiar penetración en un asunto de continua actualidad: la dignidad intangible de la persona humana en los más diversos ángulos de consideración posible, en su relación inevitable con el impacto de las tecnologías en curso, las cuales afectan nuestra vida en múltiples dimensiones y significados.