Global blood miRNA profiling unravels early signatures of immunogenicity of Ebola vaccine rVSVΔG-ZEBOV-GP

The vectored Ebola vaccine rVSVΔG-ZEBOV-GP elicits protection against Ebola Virus Disease (EVD). In a study of forty-eight healthy adult volunteers who received either the rVSVΔG-ZEBOV-GP vaccine or placebo, we profiled intracellular microRNAs (miRNAs) from whole blood cells (WB) and circulating miRNAs from serum-derived extracellular vesicles (EV) at baseline and longitudinally following vaccination. Further, we identified early miRNA signatures associated with ZEBOV-specific IgG antibody responses at baseline and up to one year post-vaccination, and pinpointed target mRNA transcripts and pathways correlated to miRNAs whose expression was altered after vaccination by using systems biology approaches. Several miRNAs were differentially expressed (DE) and miRNA signatures predicted high or low IgG ZEBOV-specific antibody levels with high classification performance. The top miRNA discriminators were WB-miR-6810, EV-miR-7151-3p, and EV-miR-4426. An eight-miRNA antibody predictive signature was associated with immune-related target mRNAs and pathways. These findings provide valuable insights into early blood biomarkers associated with rVSVΔG-ZEBOV-GP vaccine-induced IgG antibody responses

Purification and properties of pigeon kidney arginase

198-200Arginase was isolated and purified from the kidneys of pigeon (Coulmba livia) using DEAE-Sepharose CL 6B chromatography, affinity  chromatography on arginine-AH-Sepharose 4B and gel filtration on Sephadex G200 in presence of 2-mercaptoethanol. The enzyme migrated to the anode at pH 8.3 on polyacrylamide gel electrophoresis. The purified enzyme showed an average molecular mass of 179,000 daltons, optimal pH of 9.5 and temperature of 55°C and the energy of activation was found to be 10.14 kCal/mol. The Km for L-argininc was 5.0 mM. The purified enzyme was inhibited by excess product (4 mM ornithine). </span

Role of the ubiquitin–proteasome system in brain ischemia: Friend or foe?

The ubiquitin–proteasome system (UPS) is a catalytic machinery that targets numerous cellular proteins for degradation, thus being essential to control a wide range of basic cellular processes and cell survival. Degradation of intracellular proteins via the UPS is a tightly regulated process initiated by tagging a target protein with a specific ubiquitin chain. Neurons are particularly vulnerable to any change in protein composition, and therefore the UPS is a key regulator of neuronal physiology. Alterations in UPS activity may induce pathological responses, ultimately leading to neuronal cell death. Brain ischemia triggers a complex series of biochemical and molecular mechanisms, such as an inflammatory response, an exacerbated production of misfolded and oxidized proteins, due to oxidative stress, and the breakdown of cellular integrity mainly mediated by excitotoxic glutamatergic signaling. Brain ischemia also damages protein degradation pathways which, together with the overproduction of damaged proteins and consequent upregulation of ubiquitin-conjugated proteins, contribute to the accumulation of ubiquitincontaining proteinaceous deposits. Despite recent advances, the factors leading to deposition of such aggregates after cerebral ischemic injury remain poorly understood. This review discusses the current knowledge on the role of the UPS in brain function and the molecular mechanisms contributing to UPS dysfunction in brain ischemia with consequent accumulation of ubiquitin-containing proteins. Chemical inhibitors of the proteasome and small molecule inhibitors of deubiquitinating enzymes, which promote the degradation of proteins by the proteasome, were both shown to provide neuroprotection in brain ischemia, and this apparent contradiction is also discussed in this review.The work in the authors laboratory is funded by Fundação para a Ciencia e Tecnologia, COMPETE (Programa Operacional Factores de Competitividade), QREN and FEDER (Fundo Europeu de Desenvolvimento Regional) (PTDC/SAU-NMC/120144/2010, PTDC/NEUNMC/ 0198/2012 and PEst-C/SAU/LA0001/2011)

One pot selective conversion of furfural to γ-valerolactone over zirconia containing heteropoly tungstate supported on β-zeolite catalyst

A series of metal oxide and tungstophosphoric acid (TPA) supported on β-zeolite catalysts were prepared and evaluated for the one pot selective conversion of furfural (FA) to γ-valerolactone (GVL) using transfer hydrogenation approach. The characterizations of the catalysts were derived from N 2 -adsorption, FT-IR, XRD, XPS and temperature programmed desorption (TPD) techniques. The acid and base sites in the catalysts were estimated by NH 3 and CO 2 -TPD and FT-IR spectroscopy with pyridine and 2-propanol adsorption. Among the catalysts 20%ZrO 2 with 5%TPA on β-zeolite showed high activity with 85% GVL yield. The high Lewis acidic density along with basic sites are responsible for the outstanding catalytic activity of the catalyst. Based on product distribution and catalyst characteristics, a plausible mechanism was proposed. Different reaction parameters were also studied and optimum conditions were established. The catalyst was easily recovered and reused with consistent activity

Effect of crowding on residue-based electrostatic contributions.

<p>ΔΔΔG_res,crowding, broken into barstar desolvation penalty (LDP) and interaction (int), in kcal/mol, is shown for (a) selected barstar residues (see legend) and for (b) groups of barstar residues based on level of surface exposure and degree of burial (see Methods); The number above each bar indicates the actual magnitude of the selected component of ΔΔG_res without crowding present. Each bar indicates an average of 50 trials in which each crowded bound and unbound state is crowded with spheres of random, varied radii between 5 and 25 Å to 30% crowder volume density. Error bars indicate +/−1 standard error.</p

The Effect of Macromolecular Crowding on the Electrostatic Component of Barnase–Barstar Binding: A Computational, Implicit Solvent-Based Study

<div><p>Macromolecular crowding within the cell can impact both protein folding and binding. Earlier models of cellular crowding focused on the excluded volume, entropic effect of crowding agents, which generally favors compact protein states. Recently, other effects of crowding have been explored, including enthalpically-related crowder–protein interactions and changes in solvation properties. In this work, we explore the effects of macromolecular crowding on the electrostatic desolvation and solvent-screened interaction components of protein–protein binding. Our simple model enables us to focus exclusively on the electrostatic effects of water depletion on protein binding due to crowding, providing us with the ability to systematically analyze and quantify these potentially intuitive effects. We use the barnase–barstar complex as a model system and randomly placed, uncharged spheres within implicit solvent to model crowding in an aqueous environment. On average, we find that the desolvation free energy penalties incurred by partners upon binding are lowered in a crowded environment and solvent-screened interactions are amplified. At a constant crowder density (fraction of total available volume occupied by crowders), this effect generally increases as the radius of model crowders decreases, but the strength and nature of this trend can depend on the water probe radius used to generate the molecular surface in the continuum model. In general, there is huge variation in desolvation penalties as a function of the random crowder positions. Results with explicit model crowders can be qualitatively similar to those using a lowered “effective” solvent dielectric to account for crowding, although the “best” effective dielectric constant will likely depend on multiple system properties. Taken together, this work systematically demonstrates, quantifies, and analyzes qualitative intuition-based insights into the effects of water depletion due to crowding on the electrostatic component of protein binding, and it provides an initial framework for future analyses.</p></div

Sample simulated crowded environments.

<p>Here, the bound state barnase–barstar complex (red and blue) is surrounded by randomly-placed crowders (orange); the top row depicts environments in which the radius of crowders varied within a system (from 5–25 Å), at increasing crowder volume densities (left to right). The bottom row depicts environments at a constant crowder volume density, but with increasing crowder radius (left to right).</p