The Theoretical Description for Chlorantraniliprole Electrochemical Determination, Assisted by Squaraine Dye – Nano-CuS Composite

The theoretical description for the chlorantraniliprole electrochemical determination, assisted by the hybrid composite of squaraine dye with CuS nanoparticles has been described. The correspondent reaction mechanism has been proposed, and the correspondent mathematical model has been developed and analyzed by means of linear stability theory and bifurcation analysis. It has been shown that the chlorantraniprole electrochemical anodical determination on high potential may be efficiently provided by cupper sulfide nanoparticles, stabilized by the squaraine dye. On the other hand, the oscillatory and monotonic instability is also possible, being caused by DEL influences of the electrochemical stage. DOI: http://dx.doi.org/10.17807/orbital.v13i3.151

C7orf30 specifically associates with the large subunit of the mitochondrial ribosome and is involved in translation

In a comparative genomics study for mitochondrial ribosome-associated proteins, we identified C7orf30, the human homolog of the plant protein iojap. Gene order conservation among bacteria and the observation that iojap orthologs cannot be transferred between bacterial species predict this protein to be associated with the mitochondrial ribosome. Here, we show colocalization of C7orf30 with the large subunit of the mitochondrial ribosome using isokinetic sucrose gradient and 2D Blue Native polyacrylamide gel electrophoresis (BN-PAGE) analysis. We co-purified C7orf30 with proteins of the large subunit, and not with proteins of the small subunit, supporting interaction that is specific to the large mitoribosomal complex. Consistent with this physical association, a mitochondrial translation assay reveals negative effects of C7orf30 siRNA knock-down on mitochondrial gene expression. Based on our data we propose that C7orf30 is involved in ribosomal large subunit function. Sequencing the gene in 35 patients with impaired mitochondrial translation did not reveal disease-causing mutations in C7orf30

Spatial Distribution of the Pathways of Cholesterol Homeostasis in Human Retina

The retina is a light-sensitive tissue lining the inner surface of the eye and one of the few human organs whose cholesterol maintenance is still poorly understood. Challenges in studies of the retina include its complex multicellular and multilayered structure; unique cell types and functions; and specific physico-chemical environment.We isolated specimens of the neural retina (NR) and underlying retinal pigment epithelium (RPE)/choroid from six deceased human donors and evaluated them for expression of genes and proteins representing the major pathways of cholesterol input, output and regulation. Eighty-four genes were studied by PCR array, 16 genes were assessed by quantitative real time PCR, and 13 proteins were characterized by immunohistochemistry. Cholesterol distribution among different retinal layers was analyzed as well by histochemical staining with filipin. Our major findings pertain to two adjacent retinal layers: the photoreceptor outer segments of NR and the RPE. We demonstrate that in the photoreceptor outer segments, cholesterol biosynthesis, catabolism and regulation via LXR and SREBP are weak or absent and cholesterol content is the lowest of all retinal layers. Cholesterol maintenance in the RPE is different, yet the gene expression also does not appear to be regulated by the SREBPs and varies significantly among different individuals.This comprehensive investigation provides important insights into the relationship and spatial distribution of different pathways of cholesterol input, output and regulation in the NR-RPE region. The data obtained are important for deciphering the putative link between cholesterol and age-related macular degeneration, a major cause of irreversible vision loss in the elderly

Studying protein–protein affinity and immobilized ligand–protein affinity interactions using MS-based methods

This review discusses the most important current methods employing mass spectrometry (MS) analysis for the study of protein affinity interactions. The methods are discussed in depth with particular reference to MS-based approaches for analyzing protein–protein and protein–immobilized ligand interactions, analyzed either directly or indirectly. First, we introduce MS methods for the study of intact protein complexes in the gas phase. Next, pull-down methods for affinity-based analysis of protein–protein and protein–immobilized ligand interactions are discussed. Presently, this field of research is often called interactomics or interaction proteomics. A slightly different approach that will be discussed, chemical proteomics, allows one to analyze selectivity profiles of ligands for multiple drug targets and off-targets. Additionally, of particular interest is the use of surface plasmon resonance technologies coupled with MS for the study of protein interactions. The review addresses the principle of each of the methods with a focus on recent developments and the applicability to lead compound generation in drug discovery as well as the elucidation of protein interactions involved in cellular processes. The review focuses on the analysis of bioaffinity interactions of proteins with other proteins and with ligands, where the proteins are considered as the bioactives analyzed by MS

Theoretical Description for Omeprazole Cathodical Electrochemical Determination, Assisted by Omeprazole Electrochemical Determination, Assisted by the Composite Poly(1,2,4-triazole) – VO(OH)

Abstract: In this work, we describe theoretically the possibility of omeprazole electrochemical determination, assisted by the composite containing vanadium oxyhydroxide as an active substance and the polymer of 1,2,4-triazolic derivative as a mediator. The omeprazole molecule undergoes a sulfoxide to sulfide reduction process over a trivalent vanadium compound. The vanadium oxyhydroxide, at its turn, may be oxidized to a tetravalent state, represented in two forms. The electroanalytical process behavior will be illustrated by a trivariate equation-set, analysis of which confirms the efficiency of the composite of poly (1,2,4-triazole) with VO(OH). Vanadium (III) oxyhydroxide may be efficiently used for omeprazole detection both in pharmaceutical formulations, food, and biological liquids

Adult Students in the European Higher Educational Environment

The paper considers the issue of accessibility of higher education for adults – the people of various ages and social status. The author analyzes the educational policy of the European Union and its different members, and demonstrates the priority of the given issue. The Bologna agreement involves the reforms aimed at guaranteeing the lifelong education at any level.The interest to the adults education in the European Union results from the rising education requirements in the labor market; tough demographic situation and aging of professionals; redistribution of young people’s educational preferences; prolonged educational programs; flexible and consistent adult education policies in the European Union. Various approaches to interpreting a definition of the adult student are analyzed; classification according to students’ motivation and social status is given

Subunit dynamics and nucleotide-dependent asymmetry of an AAA+ transcription complex

Bacterial enhancer binding proteins (bEBPs) are transcription activators that belong to the AAA+ protein family. They form higher-order self-assemblies to regulate transcription initiation at stress response and pathogenic promoters. The precise mechanism by which these ATPases utilize ATP binding and hydrolysis energy to remodel their substrates remains unclear. Here we employed mass spectrometry of intact complexes to investigate subunit dynamics and nucleotide occupancy of the AAA+ domain of one well-studied bEBP in complex with its substrate, the σ54 subunit of RNA polymerase. Our results demonstrate that the free AAA+ domain undergoes significant changes in oligomeric states and nucleotide occupancy upon σ54 binding. Such changes likely correlate with one transition state of ATP and are associated with an open spiral ring formation that is vital for asymmetric subunit function and interface communication. We confirmed that the asymmetric subunit functionality persists for open promoter complex formation using single-chain forms of bEBP lacking the full complement of intact ATP hydrolysis sites. Outcomes reconcile low- and high-resolution structures and yield a partial sequential ATP hydrolysis model for bEBPs. © 2013 Elsevier Ltd

Analysis of the subunit organization of the eIF2B complex reveals new insights into its structure and regulation

Eukaryotic initiation factor 2B (eIF2B) is the guanine nucleotide exchange factor for eIF2 and a critical regulator of protein synthesis, (e.g., as part of the integrated stress response). Certain mutations in the EIF2B genes cause leukoencephalopathy with vanishing white matter (VWM), an often serious neurological disorder. Comprising 5 subunits, α-ε (eIF2Bε being the catalytic one), eIF2B has always been considered an αβγδε heteropentamer. We have analyzed the subunit interactions within mammalian eIF2B by using a combination of mass spectrometry and in vivo studies of overexpressed complexes to gain further insight into the subunit arrangement of the complex. Our data reveal that eIF2B is actually decameric, a dimer of eIF2B(βγδε) tetramers stabilized by 2 copies of eIF2Bα. We also demonstrate a pivotal role for eIF2Bδ in the formation of eIF2B(βγδε) tetramers. eIF2B(αβγδε)2 decamers show greater binding to eIF2 than to eIF2B(βγδε) tetramers, which may underlie the increased activity of the former. We examined the levels of eIF2B subunits in a panel of different mouse tissues and identified different levels of eIF2B subunits, particularly eIF2Bα, which implies heterogeneity in the cellular proportions of eIF2B(αβγδε) and eIF2B(βγδε) complexes, with important implications for the regulation of translation in individual cell types.Noel C. Wortham, Magdalena Martinez, Yuliya Gordiyenko, Carol V. Robinson, and Christopher G. Prou

Subunit dynamics and nucleotide-dependent asymmetry of an AAA(+) transcription complex.

Bacterial enhancer binding proteins (bEBPs) are transcription activators that belong to the AAA(+) protein family. They form higher-order self-assemblies to regulate transcription initiation at stress response and pathogenic promoters. The precise mechanism by which these ATPases utilize ATP binding and hydrolysis energy to remodel their substrates remains unclear. Here we employed mass spectrometry of intact complexes to investigate subunit dynamics and nucleotide occupancy of the AAA(+) domain of one well-studied bEBP in complex with its substrate, the σ(54) subunit of RNA polymerase. Our results demonstrate that the free AAA(+) domain undergoes significant changes in oligomeric states and nucleotide occupancy upon σ(54) binding. Such changes likely correlate with one transition state of ATP and are associated with an open spiral ring formation that is vital for asymmetric subunit function and interface communication. We confirmed that the asymmetric subunit functionality persists for open promoter complex formation using single-chain forms of bEBP lacking the full complement of intact ATP hydrolysis sites. Outcomes reconcile low- and high-resolution structures and yield a partial sequential ATP hydrolysis model for bEBPs