The copper(I)‐promoted azide–alkyne cycloaddition reaction (click chemistry) is shown to be compatible with RNA (with free 2′‐hydroxyl groups) in spite of the intrinsic lability of RNA. RNA ...degradation is minimized through stabilization of the CuI in aqueous buffer with acetonitrile as cosolvent and no other ligand; this suggests the general possibility of “ligandless” click chemistry. With the viability of click chemistry validated on synthetic RNA bearing “click”‐reactive alkynes, the scope of the reaction is extended to in‐vitro‐transcribed or, indeed, any RNA, as a click‐reactive azide is incorporated enzymatically. Once clickable groups are installed on RNA, they can be rapidly click labeled or conjugated together in click ligations, which may be either templated or nontemplated. In click ligations the resultant unnatural triazole‐linked RNA backbone is not detrimental to RNA function, thus suggesting a broad applicability of click chemistry in RNA biological studies.
Copper(I)‐promoted click chemistry is shown to be compatible with RNA (with free 2′‐hydroxyl groups) in spite of its intrinsic lability. RNA can be functionalized with reactive alkyne or azide groups through synthetic or enzymatic methods. Subsequent click labeling or ligation is rapid, and the resultant unnatural triazole‐linked backbone is not detrimental to RNA function.
El presente trabajo contiene el estudio de la evolución normativa constitucional de los principios que regulan el régimen tributario en el Ecuador, y para el efecto, se analizó las Constituciones que ...han regido desde su vida republicana; es decir, el área temática estudiada es el Derecho Constitucional Tributario, que regula la relación jurídica tributaria entre el Estado o ente acreedor (sujeto activo) y los contribuyentes o responsables de los mismos (sujetos pasivos). En este sentido, el objetivo de este trabajo es brindar una descripción normativa y teórica de la evolución de los principios tributarios que han tutelado las prestaciones contributivas de los ciudadanos ecuatorianos desde el inicio republicano de este país.
La gestión tributaria de las municipales del Ecuador se encuentra legalmente configurada como una competencia exclusiva para recaudación de sus ingresos tributarios, con el propósito de sostener ...presupuestariamente el cumplimiento de sus funciones. En este sentido, dentro de este artículo, se realiza el análisis de los ingresos tributarios que conforman los presupuestos de los años 2017, 2018 y 2019 del Municipio de Latacunga, Ecuador, así como se recoge la percepción y expectativa de la comunidad contribuyente sobre la gestión tributaria de esta municipalidad. El objetivo principal de esta investigación es determinar la problemática que conlleva a una deficiencia recaudatoria que no permite consolidar una verdadera gobernabilidad desconcentrada.
Giant axonal neuropathy (GAN) is an ultra-rare autosomal recessive, progressive neurodegenerative disease with early childhood onset that presents as a prominent sensorimotor neuropathy and commonly ...progresses to affect both the PNS and CNS. The disease is caused by biallelic mutations in the GAN gene located on 16q23.2, leading to loss of functional gigaxonin, a substrate specific ubiquitin ligase adapter protein necessary for the regulation of intermediate filament turnover. Here, we report on cross-sectional data from the first study visit of a prospectively collected natural history study of 45 individuals, age range 3-21 years with genetically confirmed GAN to describe and cross-correlate baseline clinical and functional cohort characteristics. We review causative variants distributed throughout the GAN gene in this cohort and identify a recurrent founder mutation in individuals with GAN of Mexican descent as well as cases of recurrent uniparental isodisomy. Through cross-correlational analysis of measures of strength, motor function and electrophysiological markers of disease severity, we identified the Motor Function Measure 32 to have the strongest correlation across measures and age in individuals with GAN. We analysed the Motor Function Measure 32 scores as they correspond to age and ambulatory status. Importantly, we identified and characterized a subcohort of individuals with a milder form of GAN and with a presentation similar to Charcot-Marie-Tooth disease. Such a clinical presentation is distinct from the classic presentation of GAN, and we demonstrate how the two groups diverge in performance on the Motor Function Measure 32 and other functional motor scales. We further present data on the first systematic clinical analysis of autonomic impairment in GAN as performed on a subset of the natural history cohort. Our cohort of individuals with genetically confirmed GAN is the largest reported to date and highlights the clinical heterogeneity and the unique phenotypic and functional characteristics of GAN in relation to disease state. The present work is designed to serve as a foundation for a prospective natural history study and functions in concert with the ongoing gene therapy trial for children with GAN.
•Natural uranium is cytotoxic towards dopaminergic cells but only at high concentrations (> 125 μM) which are not relevant for the vast majority of human exposures.•Uranium is located in defined ...cytoplasmic regions suggesting its accumulation within organelles yet to be determined.•Among the dopamine-related genes investigated, monoamine oxidase B gene expression is decreased even at 10 μM uranium exposure, far from cytotoxicity threshold.
Natural uranium is an ubiquitous element present in the environment and human exposure to low levels of uranium is unavoidable. Although the main target of acute uranium toxicity is the kidney, some concerns have been recently raised about neurological effects of chronic exposure to low levels of uranium. Only very few studies have addressed the molecular mechanisms of uranium neurotoxicity, indicating that the cholinergic and dopaminergic systems could be altered. The main objective of this study was to investigate the mechanisms of natural uranium toxicity, after 7-day continuous exposure, on terminally differentiated human SH-SY5Y cells exhibiting a dopaminergic phenotype. Cell viability was first assessed showing that uranium cytotoxicity only occurred at high exposure concentrations (> 125 μM), far from the expected values for uranium in the blood even after occupational exposure. SH-SY5Y differentiated cells were then continuously exposed to 1, 10, 125 or 250 μM of natural uranium for 7 days and uranium quantitative subcellular distribution was investigated by means of micro-PIXE (Particle Induced X-ray Emission). The subcellular element imaging revealed that uranium was located in defined perinuclear regions of the cytoplasm, suggesting its accumulation in organelles. Uranium was not detected in the nucleus of the differentiated cells. Quantitative analysis evidenced a very low intracellular uranium content at non-cytotoxic levels of exposure (1 and 10 μM). At higher levels of exposure (125 and 250 μM), when cytotoxic effects begin, a larger and disproportional intracellular accumulation of uranium was observed. Finally the expression of dopamine-related genes was quantified using real time qRT-PCR. The expression of monoamine oxidase B (MAO-B) gene was statistically significantly decreased after exposure to uranium while other dopamine-related genes were not modified. The down regulation of MAO-B was confirmed at the protein level. This original result suggests that the inhibition of dopamine catabolism, but also of other MAO-B substrates, could constitute selective effects of uranium neurotoxicity.
•HREE and εNd successfully trace seawater mass mixing in the central Mediterranean Sea.•Substantial EMDW flow through the Strait of Sicily detected through conservative εNd.•LREE indicate significant ...lithogenic input from the continental margin in the TYS.
Seawater rare earth element (REE) concentrations and Nd isotopic composition (εNd) are increasingly applied as valuable tracers of oceanographic processes such as water mass mixing and lithogenic inputs to seawater. However, their measurements are basically lacking in the Mediterranean Sea water column. This study analyzes 9 seawater stations around the central Mediterranean Sea to clarify the relative importance of external sources, vertical (biogeochemical) processes and lateral water mass transport in controlling REE and εNd distributions. Concentrations of REE do not show nutrient-like profiles with depth, likely indicative of relatively young waters with limited accumulation of remineralized REE. Light REE (LREE) present a non-conservative behavior, which largely peak at surface waters and rapidly decrease with depth. The negative correlation of surface LREE enrichment with offshore distance highlights the influence of continental input from the western Italian coast to the Tyrrhenian surface waters. In contrast to other regions with reported boundary exchange, this process does not modify the εNd values here. On the other side, distributions of dissolved heavy REE (HREE) and εNd display a conservative behavior that can be explained by mixing of western- (MAW and WMDW) and eastern- (LIW and EMDW) originated waters. We test this hypothesis with an Optimum Multi-Parameter Analysis (OMPA) including HREE and εNd parameters. Even though the limited data set, consistent results of water mass fractions are obtained for the four main water masses although with some particularities. While LIW takes on major importance when considering HREE in the model, EMDW fractions are preferentially detected with εNd. This latter finding implies a noticeable deep water flux across the Sicily Strait into the Western Mediterranean that was not clearly evidenced before.
Polymer biomolecule hybrids represent a powerful class of highly customizable nanomaterials. Here, we report star-polymer conjugates with DNA using a “ligandless” Cu(I) promoted azide–alkyne ...cycloaddition click reaction. The multivalency of the star-polymer architecture allows for the concomitant conjugation of other molecules along with the DNA, and the conjugation method provides control over the DNA orientation. The star-polymer DNA nanoparticles are shown to assemble into higher-order nanoassemblies through hybridization. Further, we show that the DNA strands can be utilized in controlled disassembly of the nanostructures.
Short interfering ribonucleic acids (siRNAs) are important agents for RNA interference (RNAi) that have proven useful in gene function studies and therapeutic applications. However, the efficacy of ...exogenous siRNAs for gene knockdown remains hampered by their susceptibility to cellular nucleases and impermeability to cell membranes. We report here new covalent polymer-escort siRNA constructs that address both of these constraints simultaneously. By simple postsynthetic click conjugation of polymers to the passenger strand of an siRNA duplex followed by annealing with the complementary guide strand, we obtained siRNA in which one strand includes terminal polymer escorts. The polymer escorts both confer protection against nucleases and facilitate cellular internalization of the siRNA. These autotransfecting polymer-escort siRNAs are viable in RNAi and effective in knocking down reporter and endogenous genes.
Cationic nanogels with site-selected functionality were designed for the delivery of nucleic acid payloads targeting numerous therapeutic applications. Functional cationic nanogels containing ...quaternized 2-(dimethylamino)ethyl methacrylate and a cross-linker with reducible disulfide moieties (qNG) were prepared by activators generated by electron transfer (AGET) atom transfer radical polymerization (ATRP) in an inverse miniemulsion. Polyplex formation between the qNG and nucleic acid exemplified by plasmid DNA (pDNA) and short interfering RNA (siRNA duplexes) were evaluated. The delivery of polyplexes was optimized for the delivery of pDNA and siRNA to the Drosophila Schneider 2 (S2) cell-line. The qNG/nucleic acid (i.e., siRNA and pDNA) polyplexes were found to be highly effective in their capabilities to deliver their respective payloads.
El ingreso en Ecuador al servicio público está establecido bajo la Ley Orgánica del Servicio Público (LOSEP). Esta sirve para determinar las mejores personas, profesionalidad, conocimientos y ética ...para prestar sus servicios. El objetivo de la presente investigación consiste en analizar un proyecto de reforma a la LOSEP para la aplicabilidad del reingreso de servidores destituidos de su cargo en una institución pública, elegidos por votación popular. La metodología tiene una investigación explicativa, empleando métodos teóricos-prácticos, con lo cual los resultados contribuyan a dilucidar el reingresar a la institución que fue elegido por votación popular y de la cual fue destituido.
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