Purification of alpha-galactosidase by affinity precipitation with alginate

Affinity precipitation is a technique which is known for over 20 years, but has recently received more attention due to the development of new materials for its implementation. It is a relatively simple, convenient, and reproducible technique that results in high target molecule recovery at high specificity. We describe, here, an efficient and rapid purification procedure for Vicia faba alpha-galactosidase (EC 3.2.1.22) by using affinity precipitation with alginate. The enzyme was purified with 43% activity yield and 40-fold purification. SDS-PAGE of the purified enzyme showed a single band and a subunit weight of 44 kDa. The properties of the enzyme were also searched. The results showed that the general properties of the enzyme offer potential for use of this alpha-galactosidase in several production processes.     

Additive Effect of Dextrans on the Stability of Horseradish Peroxidase

The influence of various concentration (10, 20, and 30% w/v) of different molar weighted dextrans as additives on the stability of HRP has been studied in aqueous medium. Native HRP preparations were formulated with different additives for storage stabilization and better performance at high temperature and pH. The results obtained show a stabilizing effect in the presence of an additive (75 kDa dextran). The enzyme with 75 kDa dextran (in concentration 10% w/v) showed the highest thermal resistance and the best performance for long-term storage at pH 5.0. In the presence of the 75 kDa dextran, the enzyme activity was increased threefold at 25 °C and lost only 15% activity in 2 h at 50 °C in comparison to the native enzyme which lost all its activity. In addition, dextran protected HRP against inactivation by air bubbles.     

A Mechanistic View of the Role of E3 in Sumoylation

Sumoylation, the covalent attachment of SUMO (Small Ubiquitin-Like Modifier) to proteins, differs from other Ubl (Ubiquitin-like) pathways. In sumoylation, E2 ligase Ubc9 can function without E3 enzymes, albeit with lower reaction efficiency. Here, we study the mechanism through which E3 ligase RanBP2 triggers target recognition and catalysis by E2 Ubc9. Two mechanisms were proposed for sumoylation. While in both the first step involves Ubc9 conjugation to SUMO, the subsequent sequence of events differs: in the first E2-SUMO forms a complex with the target and E3, followed by SUMO transfer to the target. In the second, Ubc9-SUMO binds to the target and facilitates SUMO transfer without E3. Using dynamic correlations obtained from explicit solvent molecular dynamic simulations we illustrate the key roles played by allostery in both mechanisms. Pre-existence of conformational states explains the experimental observations that sumoylation can occur without E3, even though at a reduced rate. Furthermore, we propose a mechanism for enhancement of sumoylation by E3. Analysis of the conformational ensembles of the complex of E2 conjugated to SUMO illustrates that the E2 enzyme is already largely pre-organized for target binding and catalysis; E3 binding shifts the equilibrium and enhances these pre-existing populations. We further observe that E3 binding regulates allosterically the key residues in E2, Ubc9 Asp100/Lys101 E2, for the target recognition.     

Respiratory muscle function during CO2 rebreathing with inspiratory flow-resistive loading

We investigated the respiratory muscle contribution to inspiratory load compensation by measuring diaphragmatic and intercostal electromyograms (EMGdi and EMGic), transdiaphragmatic pressure (Pdi), and thoracoabdominal motion during CO2 rebreathing with and without 15 cmH2O X l-1 X s inspiratory flow resistance (IRL) in normal sitting volunteers. During IRL compared with control, Pdi measured during airflow and during airway occlusion increased for a given change in CO2 partial pressure and EMGdi, and there was a greater decrease in abdominal (AB) end expiratory anteroposterior dimensions with increased expiratory gastric pressure (Pga), this leading to an inspiratory decline in Pga with outward AB movement, indicating a passive component to the descent of the abdomen-diaphragm. The response of EMGic to IRL was similar to that of EMGdi, though rib cage (RC)-Pga plots did infer intercostal muscle contribution. We conclude that during CO2 rebreathing with IRL there is improved diaphragmatic neuromuscular coupling, the prolongation of inspiration promoting a force-velocity advantage, and increased AB action serving to optimize diaphragm length and configuration, as well as to provide its own passive inspiratory action. Intercostal action provides increased assistance also. Therefore, compensation for inspiratory resistive loads results from the combined and integrated effort of all respiratory muscle groups.     

Biosynthesis of palladium nanoparticles using Diospyros kaki leaf extract and determination of antibacterial efficacy

Abstract

Palladium, the building block of white gold, has been found to exhibit extraordinary properties in nanotechnological products produced in recent years. The most prominent feature of palladium is adsorbing and storing high levels of hydrogen. Therefore, the demand for palladium in the world increased excessively in the 2000s. In the present study, palladium nanoparticles (PdNPs) were biosynthesized by the extract of Diospyros kaki leaves as bio-stimulator. D. kaki, also called persimmon, was collected in a local area in Istanbul Turkey. PdNP formation was screened by analyzing UV-Vis spectrophotometer at 250–550?nm. The nanoparticles were characterized by scanning electron microscope which revealed that the biosynthesized PdNPs were in sizes ranging from 50 to 120?nm. Fourier transform infrared spectroscopy applied on both D. kaki leaf extract and PdNPs was used to decide on the reactive groups managing the reduction of the biosynthesized nanoparticles. Also, the PdNPs showed reasonably proficient antibacterial efficacy for both Escherichia coli and Staphylococcus aureus and the zones of inhibition were found as 18 and 10.5 mm, respectively.     

Evaluation the Weekly Intake of Some Wild Edible Indigenous Mushrooms Collected in Different Regions in Tunceli,Turkey

Biological Trace Element Research - The quantity of some essential and non-essential elements of wild edible mushroom samples collected from Tunceli Province of Turkey was determined by using flame...     

Effects of chronic ethanol treatment on glial fibrillary acidic protein expression in adult rat optic nerve: an immunocytochemical study

Glial fibrillary acidic protein (GFAP) is used as a marker of astrocyte response to various central nervous system injuries. In the present study, the effects of chronic ethanol administration on GFAP immunoreactivity were evaluated in astrocytes of the adult optic nerve head. The results demonstrated that ethanol exposure significantly and dramatically increases GFAP immunoreactivity and the number of immunoreactive astrocytes (p<0.001). In addition, GFAP immunoreactive cells in the optic nerve showed extensive hypertrophy (p<0.001).