Ribosome formation from subunits studied by stopped-flow and Rayleigh light scattering

Light scattering and standard stopped-flow techniques were used to monitor rapid association of ribosomal subunits during initiation of eubacterial protein synthesis. The effects of the initiation factors IF1, IF2, IF3 and buffer conditions on subunit association were studied along with the role of GTP in this process. The part of light scattering theory that is essential for kinetic measurements is high-lighted in the main text and a more general treatment of Rayleigh scattering from macromolecules is given in an appendix

Isolation of Bacterial Ribosomes with Monolith Chromatography

We report the development of a rapid chromatographic method for the isolation of bacterial ribosomes from crude cell lysates in less than ten minutes. Our separation is based on the use of strong anion exchange monolithic columns. Using a simple stepwise elution program we were able to purify ribosomes whose composition is comparable to those isolated by sucrose gradient ultracentrifugation, as confirmed by quantitative proteomic analysis (iTRAQ). The speed and simplicity of this approach could accelerate the study of many different aspects of ribosomal biology

Multinuclear MRS at 7T uncovers exercise driven differences in skeletal muscle energy metabolism between young and seniors

Purpose:&nbsp;Aging is associated with changes in muscle energy metabolism. Proton (1H) and phosphorous (31P) magnetic resonance spectroscopy (MRS) has been successfully applied for non-invasive investigation of skeletal muscle metabolism. The aim of this study was to detect differences in adenosine triphosphate (ATP) production in the aging muscle by&nbsp;31P-MRS and to identify potential changes associated with buffer capacity of muscle carnosine by&nbsp;1H-MRS. Methods:&nbsp;Fifteen young and nineteen elderly volunteers were examined.&nbsp;1H and&nbsp;31P-MRS spectra were acquired at high field (7T). The investigation included carnosine quantification using&nbsp;1H-MRS and resting and dynamic&nbsp;31P-MRS, both including saturation transfer measurements of phosphocreatine (PCr), and inorganic phosphate (Pi)-to-ATP metabolic fluxes. Results:&nbsp;Elderly volunteers had higher time constant of PCr recovery (&tau;PCr) in comparison to the young volunteers. Exercise was connected with significant decrease in PCr-to-ATP flux in both groups. Moreover, PCr-to-ATP flux was significantly higher in young compared to elderly both at rest and during exercise. Similarly, an increment of Pi-to-ATP flux with exercise was found in both groups but the intergroup difference was only observed during exercise. Elderly had lower muscle carnosine concentration and lower postexercise pH. A strong increase in phosphomonoester (PME) concentration was observed with exercise in elderly, and a faster Pi:PCr kinetics was found in young volunteers compared to elderly during the recovery period. Conclusion:&nbsp;Observations of a massive increment of PME concentration together with high Pi-to-ATP flux during exercise in seniors refer to decreased ability of the muscle to meet the metabolic requirements of exercise and thus a limited ability of seniors to effectively support the exercise load.</p

Synthesis and field emission characteristics of W5O14nanowires film

The W5O14 nanowires are metallic oxides with specific resistivity of 27 mu Omega cm and diameters bellow 100 nm. The field emission characteristics of the films composed of these nanowires have been investigated. The emitting current densities up to 6.4 mA/cm(2) have been obtained at very low electric field of about 3 V/mu m. The samples were allowed to emit for more than 100 h without showing significant decays of the emitting current and without substantial current oscillations. These characteristics make these nanowires very promising for the realization of large area field emitting cathodes. (C) 2017 Elsevier B.V. All rights reserved