Smart polymer mediated purification and recovery of active proteins from inclusion bodies

Obtaining correctly folded proteins from inclusion bodies of recombinant proteins expressed in bacterial hosts requires solubilization with denaturants and a refolding step. Aggregation competes with the second step. Refolding of eight different proteins was carried out by precipitation with smart polymers. These proteins have different molecular weights, different number of disulfide bridges and some of these are known to be highly prone to aggregation. A high throughput refolding screen based upon fluorescence emission maximum around 340 nm (for correctly folded proteins) was developed to identify the suitable smart polymer. The proteins could be dissociated and recovered after the refolding step. The refolding could be scaled up and high refolding yields in the range of 8 mg L-1 (for CD4D12, the first two domains of human CD4) to 58 mg L-1 (for malETrx, thioredoxin fused with signal peptide of maltose binding protein) were obtained. Dynamic light scattering (DLS) showed that polymer if chosen correctly acted as a pseuclochaperonin and bound to the proteins. It also showed that the time for maximum binding was about 50 min which coincided with the time required for incubation (with the polymer) before precipitation for maximum recovery of folded proteins. The refolded proteins were characterized by fluorescence emission spectra, circular dichroism (CD) spectroscopy, melting temperature (T-m), and surface hydrophobicity measurement by ANS (8-anilinol-naphthalene sulfonic acid) fluorescence. Biological activity assay for thioredoxin and fluorescence based assay in case of maltose binding protein (MBP) were also carried out to confirm correct refolding. (C) 2012 Elsevier B.V. All rights reserved.

Inclusion of body doping in compact models for fully-depleted common double gate MOSFET adapted to gate-oxide thickness asymmetry

Since it is difficult to find the analytical solution of the governing Poisson equation for double gate MOSFETs with the body doping term included, the majority of the compact models are developed for undoped-body devices for which the analytical solution is available. Proposed is a simple technique to included a body doping term in such surface potential based common double gate MOSFET models also by taking into account any differences between the gate oxide thickness. The proposed technique is validated against TCAD simulation and found to be accurate as long as the channel is fully depleted.

Accommodating Unwelcome Guests in Inorganic Layered Hosts: Inclusion of Chloranil in a Layered Double Hydroxide

The host-guest chemistry of most inorganic layered solids is limited to ion-exchange reactions. The guest species are either cations or anions to compensate for the charge deficit, either positive or negative, of the inorganic layers. Here, we outline a strategy to include neutral molecules like ortho- and para-chloranil, that are known to be good acceptors in donor-acceptor or charge-transfer complexes, within the galleries of a layered solid. We have succeeded in including neutral ortho- and para-chloranil molecules within the galleries of an Mg-Al layered double hydroxide (LDH) by using charge-transfer interactions with preintercalated p-aminobenzoate ions as the driving force. The p-aminobenzoate ions are introduced in the Mg-Al LDH via ion exchange. The intercalated LDH can adsorb ortho- and para-chloranil from chloroform solutions by forming charge-transfer complexes with the p-aminobenzoate anions present in the galleries. We use X-ray diffraction, spectroscopy, and molecular dynamics simulations to establish the nature of interactions and arrangement of the charge-transfer complex within the galleries of the layered double hydroxide.

Detailed investigation of a gamma-cyclodextrin inclusion complex with L-thyroxine for improved pharmaceutical formulations

Thyroxine is a naturally occurring human hormone produced by the thyroid gland. Clinical applications of thyroxine to treat several chronic disorders are limited by poor water solubility and instability under physiological conditions. An inclusion complex of levo-thyroxine (l-thyroxine), the active form of the hormone with gamma cyclodextrin (gamma-CD) has been obtained and studied with the aim of improving oral delivery rather than the injection formulation of the sodium salt. In addition to greater patient acceptability, inclusion complexes often improve aqueous solubility and bioavailability, stability, and reduce toxicity of drugs, thus providing enhanced pharmaceutical formulations. Physicochemical characterization of the inclusion complex was carried out using Fourier transform infrared spectroscopy, X-ray diffractometry, differential scanning calorimetry, scanning electron microscopy and proton nuclear magnetic resonance spectroscopy. Intermolecular dipolar interactions for the inclusion complex were also studied using 2 dimensional ROESY experiments. Formation of the inclusion complex between the protons H3 and H5 of cyclodextrin with aromatic protons of thyroxine was confirmed by their dipolar interaction. Molecular modelling was used to understand the basis for the complex formation and predict the formation of other complexes. Interestingly, we found that l-thyroxine forms an inclusion complex only with the larger gamma-CD and not with other available alpha and beta forms.

Novel ATPase activity of the polyprotein intermediate, Viral Protein genome-linked-Nuclear Inclusion-a protease, of Pepper vein banding potyvirus

Potyviruses temporally regulate their protein function by polyprotein processing. Previous studies have shown that VPg (Viral Protein genome-linked) of Pepper vein banding virus interacts with the NIa-Pro (Nuclear Inclusion-a protease) domain, and modulates the kinetics of the protease. In the present study, we report for the first time that VPg harbors the Walker motifs A and B, and the presence of NIa-Pro, especially in cis (cleavage site (E191A) VPg-Pro mutant), is essential for manifestation of the ATPase activity. Mutation of Lys47 (Walker motif A) and Asp88:Glu89 (Walker motif B) to alanine in E191A VPg-Pro lead to reduced ATPase activity, confirming that this activity was inherent to VPg. We propose that potyviral VPg, established as an intrinsically disordered domain, undergoes plausible structural alterations upon interaction with globular NIa-Pro which induces the ATPase activity. (C) 2012 Elsevier Inc. All rights reserved.

Charge-transfer-driven inclusion of neutral TCNQ molecules in the galleries of a layered double hydroxide: an experimental and computational study

The layered double hydroxides (LDH) or anionic clays are an important class of ion-exchange materials. They consist of positively charged brucite-like inorganic sheets with charge-compensating exchangeable anions in the interlamellar space. Here we show how neutral TCNQ (7,7,8,8-tetracyanoquinodimethane) molecules can be included within the galleries of an LDH. To do so, we exploit the fact that TCNQ is a good electron acceptor that forms donor acceptor complexes with a variety of donors. The electron donor aniline was intercalated into a Mg-Al LDH as p-aminobenzoate (AB) ions by a conventional ion-exchange reaction. We show here that neutral TCNQ molecules may be driven into the galleries of the layered solid by charge-transfer complex formation with the intercalated p-aminobenzoate anions. We use diffraction and spectroscopic measurements in combination with molecular dynamics simulations and quantum chemical calculations to establish the nature of interactions and arrangement of the charge-transfer complex within the galleries of the layered double hydroxide. Electrostatic interactions between the TCNQ molecules and the anchored AB ions, subsequent to charge transfer, are the driving force for the inclusion of TCNQ molecules in the galleries of the LDH.

Anisotropic thermopiezoelectric solids with an elliptic inclusion or a hole under uniform heat flow

The two-dimensional problem of a thermopiezoelectric material containing an elliptic inclusion or a hole subjected to a remote uniform heat flow is studied. Based on the extended Lekhnitskii formulation for thermopiezoelectricity, conformal mapping and Laurent series expansion, the explicit and closed-form solutions are obtained both inside and outside the inclusion (or hole). For a hole problem, the exact electric boundary conditions on the hole surface are used. The results show that the electroelastic fields inside the inclusion or the electric field inside the hole are linear functions of the coordinates. When the elliptic hole degenerates into a slit crack, the electroelastic fields and the intensity factors are obtained. The effect of the heat how direction and the dielectric constant of air inside the crack on the thermal electroelastic fields are discussed. Comparison is made with two special cases of which the closed solutions exist and it is shown that our results are valid.

La filosofía educativa de Juan Luis Vives

Juan Luis Vives como hombre de las letras, la filosofía, las humanidades y la educación en el Renacimiento, fue inspirador del presente trabajo de conclusión de la etapa formativa de la Licenciatura de Filosofía, pues sus ideas, sus escritos y sobre todo su vida son un modelo integral de pensamiento y de comportamiento que sigue actualmente vigente y puede brindar aportes al hombre del siglo XXI. El tema de estudio del presente trabajo es la filosofía educativa del valenciano, en el contexto de su pensamiento humanista y de las corrientes que conformaron la época renacentista.

Propuesta educativa para la promoción de una cultura de donación de órganos

La escasez de órganos para donación y trasplante es un problema acuciante que involucra a toda la sociedad. Existen diversos prejuicios, racionales y emocionales, por los que muchas personas son reacias a donar sus órganos, sin saber o sin comprender que este gesto podría salvar vidas. El autor ahonda en esta problemática médico-social y plantea una propuesta para revertirla, comenzando con la educación desde el nivel primario y abarcando diferentes niveles educativos y ámbitos de la sociedad. Pone especial énfasis en la formación de los jóvenes, y su entorno social y familiar, quienes juegan un papel preponderante en el desarrollo de futuros programas educativos. Esta propuesta es integral y no implica controversias legales ni éticomorales, por lo que se presenta como una alternativa para derribar las barreras, conscientes e inconscientes, y la desinformación generadoras de una sociedad no donante que se niega una posibilidad de vida a sí misma.

Verba doctoris : la fecundidad educativa de las palabras del maestro

Resumen: En el mundo educativo actual las corrientes pedagógicas se han visto sumidas en lo que podríamos denominar «el olvido del maestro», pues este se torna ininteligible cuando no hay una verdad que comunicar. La educación se convierte entonces en una construcción por parte del alumno de un mundo de significados subjetivos y cambiantes, que el maestro solo estimula. Frente a esto encontramos la enseñanza de santo Tomás de Aquino, Doctor Humanitatis, quien nos recuerda que las palabras del maestro, verba doctoris, son comunicativas de la verdad ya conocida. Solo fundados en este principio es posible devolver a la palabra educativa la fecundidad que le corresponde, tan necesaria para el perfeccionamiento del hombre y de la sociedad. En este artículo se presenta una reflexión acerca del lugar que ocupa la palabra verdadera en la educación de los hombres, mostrando cómo la vida humana no tiende solo a expresarse en la palabra, sino a ser fecunda en la palabra educativa.

Estado e imaginario tecnológico : un análisis de las reconfiguraciones en las políticas educativas nacionales de incorporación de TIC

Este artículo presenta los primeros resultados de una investigación mayor que se ubica en la articulación entre las políticas educativas de incorporación de TIC y el discurso docente de nivel medio, considerando dicha articulación en el marco del imaginario tecno-comunicacional contemporáneo. Ante los procesos de internacionalización de la toma de decisiones, la hegemonía neoliberal como paradigma socio-económico y los discursos de la Sociedad de la Información, Argentina, y en general los Estados nacionales, han sido permeables a los discursos sociales que promueven la incorporación de TIC. Este trabajo, desde una perspectiva socio-discursiva, se focaliza en el nivel de las políticas educativas definidas por el Estado argentino en la última década. A partir del rastreo de líneas de sentido que atraviesan los discursos analizados, se observa una búsqueda de distanciamiento del abordaje instrumental y el desplazamiento hacia otros núcleos significantes como formación ciudadana e inclusión social.

Educação legislativa : as escolas do Legislativo e a função educativa do parlamento

O adequado funcionamento da democracia exige determinadas capacidades e competências por parte dos agentes políticos e sociais. O texto trata das possibilidades e das responsabilidades da educação legislativa como instrumento para a construção dessas competências no âmbito do parlamento e do papel das escolas do legislativo nesse contexto.

Regulação da radiodifusão educativa

Consultoria Legislativo da Área XIV - Ciência e Tecnologia, Comunicação e Informática.