Effect of Betaine and Arginine on Interaction of αB-Crystallin with Glycogen Phosphorylase b

Protein–protein interactions (PPIs) play an important role in many biological processes in a living cell. Among them chaperone–client interactions are the most important. In this work PPIs of αB-crystallin and glycogen phosphorylase b (Phb) in the presence of betaine (Bet) and arginine (Arg) at 48 °C and ionic strength of 0.15 M were studied using methods of dynamic light scattering, differential scanning calorimetry, and analytical ultracentrifugation. It was shown that Bet enhanced, while Arg reduced both the stability of αB-crystallin and its adsorption capacity (AC₀) to the target protein at the stage of aggregate growth. Thus, the anti-aggregation activity of αB-crystallin increased in the presence of Bet and decreased under the influence of Arg, which resulted in inhibition or acceleration of Phb aggregation, respectively. Our data show that chemical chaperones can influence the tertiary and quaternary structure of both the target protein and the protein chaperone. The presence of the substrate protein also affects the quaternary structure of αB-crystallin, causing its disassembly. This is inextricably linked to the anti-aggregation activity of αB-crystallin, which in turn affects its PPI with the target protein. Thus, our studies contribute to understanding the mechanism of interaction between chaperones and proteins.     

Brain Neurons during Physiological Aging: Morphological Features,Autophagic and Mitochondrial Contribution

Accumulating data suggest that the brain undergoes various changes during aging. Among them are loss of both white and gray matter, neurons and synapses degeneration, as well as oxidative, inflammatory, and biochemical changes. The above-mentioned age-related features are closely related to autophagy and mitochondria. Therefore, we aimed to reveal the most peculiar morphological features of brain nervous tissue and to characterize the expression of autophagy and mitochondrial immunohistochemical biomarkers in neurons of different human brain zones during aging. Counting the number of neurons as well as Microtubule-associated proteins 1A/1B light chain 3B (LC3B), Heat shock protein 70 (HSP70), Lysosome-associated membrane protein type 2A (LAMP2A), Alpha subunit of ATP synthase (ATP5A), and Parkinson disease protein 7 (DJ1) immunohistochemical staining were performed on FFPE samples of human prefrontal cortex, corpus striatum, and hippocampus obtained from autopsy. Statistical analysis revealed a loss of neurons in the studied elderly group in comparison to the young group. When the expression of macroautophagy (LC3B), chaperon-mediated autophagy (HSP70, LAMP2A), and mitochondrial respiratory chain complex V (ATP5A) markers for the young and elderly groups were compared, the latter was found to have a significantly higher rate of optical density, whilst there was no significance in DJ1 expression. These findings, while preliminary, suggest that both autophagy and mitochondria are involved in neuronal maintenance during aging and could indicate their potential role in adaptive mechanisms that occur in aging.     

Advances in Ultraviolet Light Technology for Non-thermal Processing of Liquid Foods

A negative, public reaction is growing over the addition of chemical preservatives to liquid foods and beverages to extend their shelf life and to protect against foodborne pathogens. As a physical method, ultraviolet light (UV) irradiation has a positive consumer image and is of interest to the food industry as a low cost non-thermal method of preservation. Recent advances in the science and engineering of UV light irradiation have demonstrated that this technology holds considerable promise as an alternative to traditional thermal pasteurization for liquid foods and ingredients, fresh juices, soft drinks, and beverages. However, its use for treating foods is still limited due to low UV transmittance of liquid foods. The goal of this review is to provide a summary of the basic principles of UV light generation and propagation with emphasis on its applications for liquid food processing. The review includes information on critical product and process factors that affect UV light inactivation and consequently the delivery of a required scheduled process in liquids foods; measuring and modeling of UV inactivation, and the important effects of UV light on overall quality and nutritional value of liquid foods. The commercially available UV light sources and UV reactor designs that were used for liquid foods treatment are reviewed. The research priorities and challenges that need to be addressed for the successful development of UV technology for liquid foods treatment are discussed.     

Direct synthesis of carbon nanofibers on the surface of copper powder

A novel approach to synthesize carbon nanofibers (CNFs) directly on the surface of metal μm-sized particles to evenly disperse the carbon nanomaterials in a composite material was proposed. As a metal matrix, 5–10 μm copper particles were utilized. As a carbon source, C₂H₂, CH₄ and CO were examined. The best conditions were found to be in C₂H₂ (30 cm³/min) and H₂ (260 cm³/min) atmosphere at the temperature of 750 °C. The composites based on copper and CNFs prepared by vacuum hot pressing showed the increase in hardness from 35 to 60 kg/mm² almost retaining pure copper electrical properties.     

Robustness of quantized control systems with mismatch between coder/decoder initializations

This paper analyzes the stability of linear systems with quantized feedback in the presence of mismatch between the initial conditions at the coder and decoder. Under the assumption of the perfect channel, we show that using the scheme proposed in [Liberzon, D., & Neši?, D. (2007). Input-to-state stabilization of linear systems with quantized state measurements. Institute of Electrical and Electronic Engineers Transaction on Automatic Control, 52, 767-781] it is possible to achieve stability with exponential convergence of linear systems with quantized feedback when the coder and decoder are initialized at different initial conditions.     

Approach to 3-d ultrasound high resolution imaging for mechanically moving large-aperture transducer based upon Fourier transform

A new three-dimensional (3-D) acoustic image formation technique is proposed that is based on the transmission of wide bandwidth pulse signals and the application of the 3-D fast Fourier transform. A solution to the Helmholtz wave equation has been obtained using the Born approximation. The solution contains analytical expressions for the spatial spectra of the transmit and receive radiation patterns for transducers of various geometries with lenses of fixed focal distances. It has been shown that the proposed algorithms allow for radiation patterns with constant widths at depths both behind and in front of the focal point, starting practically from the plane of the transducer. The theoretical and experimental investigations and computer simulation for both spherical and rectangular transducer shapes have been performed. The results were used to estimate the beamwidths and the side lobe levels. A variant of the linear array has been studied for a cylindrical lens of a fixed focal distance moving in a lateral direction. It has been shown that, in this case, a high resolution (of the order of a few wavelengths) can be achieved along all three Cartesian coordinates at a very high scanning velocity. The influence of the moving scatterers' velocity in inhomogeneous medium on the spatial radiation pattern characteristics has been estimated.