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Secondary metabolites derived from plants are recognized as valuable products with several successful applications in the pharmaceutical, cosmetic, and food industries. The major limitation to the broader implementation of these compounds is their low manufacturing efficiency. Current efforts to overcome unprofitability depend mainly on biotechnological methods, especially through the application of plant in vitro cultures. This concept allows unprecedented bioengineering opportunities for culture system modifications with in situ product removal. The silica-based xerogels can be used as a novel, porous biomaterial characterized by a large surface area and high affinity to lipophilic secondary metabolites produced by plant tissue. This study aimed to investigate the influence of xerogel-based biomaterials functionalized with methyl, hydroxyl, carboxylic, and amine groups on Rindera graeca transgenic root growth and the production of naphthoquinone derivatives. The application of xerogel-based scaffolds functionalized with the methyl group resulted in more than 1.5 times higher biomass proliferation than for reference untreated culture. The naphthoquinone derivatives' production was noted exclusively in culture systems supplemented with xerogel functionalized with methyl and hydroxyl groups. Applying chemically functionalized xerogels as in situ adsorbents allowed for the enhanced growth and productivity of in vitro cultured R. graeca transgenic roots, facilitating product isolation due to their selective and efficient accumulation.
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The pressure to reduce mineral fertilization and the amount of pesticides used has become a factor limiting production growth, as has the elimination of many crop protection chemicals from the market. A key condition for this to be an effective form of protection is the use of varieties with higher levels of resistance. The most effective and fastest way to assist in the selection and control of pathogens is the conducting of genome-wide association studies. These are useful tools for identifying candidate genes, especially when combined with QTL mapping to map and validate loci for quantitative traits. The aim of this study was to identify new markers coupled to genes that determine maize plant resistance to fusarium head blight through the use of next-generation sequencing, association and physical mapping, and to optimize diagnostic procedures to identify selected molecular markers coupled to plant resistance to this fungal disease. As a result of field experiments and molecular analyses, molecular markers coupled to potential genes for resistance to maize ear fusariosis were selected. The newly selected markers were tested against reference genotypes. As a result of the analyses, it was found that two markers (11801 and 20607) out of the ten that were tested differentiated between susceptible and resistant genotypes. Marker number 11801 proved to be the most effective, with a specious product of 237 bp appearing for genotypes 1, 3, 5, 9 and 10. These genotypes were characterized by a field resistance of 4-6 on the 9° scale (1 being susceptible, 9 being resistant) and for all genotypes except 16 and 20, which were characterized by a field resistance of 9. In the next step, this marker will be tested on a wider population of extreme genotypes in order to use it for the preliminary selection of fusarium-resistant genotypes, and the phosphoenolpyruvate carboxylase kinase 1 gene coupled to it will be subjected to expression analysis.
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Fusarium , Fusarium/genética , Zea mays/metabolismo , Sitios de Carácter Cuantitativo , Resistencia a la Enfermedad/genética , Estudio de Asociación del Genoma Completo , Secuenciación de Nucleótidos de Alto Rendimiento , Tecnología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiologíaRESUMEN
Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare, incurable genetic disease that belongs to the group of polyglutamine (polyQ) diseases. DRPLA is the most common in the Japanese population; however, its global prevalence is also increasing due to better clinical recognition. It is characterized by cerebellar ataxia, myoclonus, epilepsy, dementia, and chorea. DRPLA is caused by dynamic mutation of CAG repeat expansion in ATN1 gene encoding the atrophin-1 protein. In the cascade of molecular disturbances, the pathological form of atrophin-1 is the initial factor, which has not been precisely characterized so far. Reports indicate that DRPLA is associated with disrupted protein-protein interactions (in which an expanded polyQ tract plays a crucial role), as well as gene expression deregulation. There is a great need to design efficient therapy that would address the underlying neurodegenerative process and thus prevent or alleviate DRPLA symptoms. An in-depth understanding of the normal atrophin-1 function and mutant atrophin-1 dysfunction is crucial for this purpose. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Ataxia Cerebelosa , Epilepsias Mioclónicas Progresivas , Humanos , Atrofia , Ataxia Cerebelosa/genética , Mutación/genética , Epilepsias Mioclónicas Progresivas/genética , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismoRESUMEN
1H spin-lattice relaxation experiments have been performed for water-Bovine Serum Albumin (BSA) mixtures, including 20%wt and 40%wt of BSA. The experiments have been carried out in a frequency range encompassing three orders of magnitude, from 10 kHz to 10 MHz, versus temperature. The relaxation data have been thoroughly analyzed in terms of several relaxation models with the purpose of revealing the mechanisms of water motion. For this purpose, four relaxation models have been used: the data have been decomposed into relaxation contributions expressed in terms of Lorentzian spectral densities, then three-dimensional translation diffusion has been assumed, next two-dimensional surface diffusion has been considered, and eventually, a model of surface diffusion mediated by acts of adsorption to the surface has been employed. In this way, it has been demonstrated that the last concept is the most plausible. Parameters describing the dynamics in a quantitative manner have been determined and discussed.
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Imagen por Resonancia Magnética , Agua , Espectroscopía de Resonancia Magnética/métodos , Albúmina Sérica Bovina , DifusiónRESUMEN
A base-catalysed methyltrimethoxysilane (MTMS) colloidal gel formation was implemented as a cellular automaton (CA) system, specifically diffusion and/or reaction-limited aggregation. The initial characteristic model parameters were determined based on experimental synthesis of MTMS-based, ambient-pressure-dried aerogels. The applicability of the numerical approach to the prediction of gels' condensation kinetics and their structure was evaluated. The developed model reflects the kinetics properly within the investigated chemical composition range (in strongly reaction-limited aggregation conditions) and, to a slightly lesser extent, the structural properties of aggregates. Ultimately, a relatively simple numerical model reflecting silica-based gel formation was obtained and verified experimentally. The CA simulations have proved valid for understanding the relation between the initial chemical composition and kinetics constants of MTMS-based synthesis and their impact on secondary particle aggregation process kinetics.
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Dióxido de Silicio , Dióxido de Silicio/química , Cinética , Geles/química , Gel de Sílice , DifusiónRESUMEN
The main challenge of agriculture in the 21st century is the continuous increase in food production. In addition to ensuring food security, the goal of modern agriculture is the continued development and production of plant-derived biomaterials. Conventional plant breeding methods do not allow breeders to achieve satisfactory results in obtaining new varieties in a short time. Currently, advanced molecular biology tools play a significant role worldwide, markedly contributing to biological progress. The aim of this study was to identify new markers linked to candidate genes determining grain yield. Next-generation sequencing, gene association, and physical mapping were used to identify markers. An additional goal was to also optimize diagnostic procedures to identify molecular markers on reference materials. As a result of the conducted research, 19 SNP markers significantly associated with yield structure traits in maize were identified. Five of these markers (28629, 28625, 28640, 28649, and 29294) are located within genes that can be considered candidate genes associated with yield traits. For two markers (28639 and 29294), different amplification products were obtained on the electrophorograms. For marker 28629, a specific product of 189 bp was observed for genotypes 1, 4, and 10. For marker 29294, a specific product of 189 bp was observed for genotypes 1 and 10. Both markers can be used for the preliminary selection of well-yielding genotypes.
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Fitomejoramiento , Zea mays , Zea mays/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Tecnología , Grano Comestible/genéticaRESUMEN
Seed vigor and seed germination are very important traits, determined by several factors including genetic and physical purity, mechanical damage, and physiological condition, characterized by maintaining a high seed vigor and stable content after storage. The search for molecular markers related to improvement in seed vigor under adverse condition is an important issue in maize breeding currently. Higher sowing quality of seeds is necessary for the development of the agriculture production and better ability to resist all kinds of adversity in the seeds' storage. Condition is a very important factor affecting the yield of plants, thanks to the construction of their vitality. Identification of molecular markers associated with seed germination and seed vigor may prove to be very important in the selection of high-yielding maize varieties. The aim of this study was to identify and select new markers for maize (SNP and SilicoDArT) linked to genes influencing the seed germination and seed vigor in inbred lines of maize (Zea mays L.). The plant material used for the research was 152 inbred maize lines. The seed germination and seed vigor were analyzed. For identification of SNP and SilicoDArT markers related to the seed germination and seed vigor, the SilicoDarT technique developed by Diversity Arrays Technology was used. The analysis of variance indicated a statistically significant differentiation between genotypes for both observed traits. Positive (r = 0.41) correlation (p < 0.001) between seed germination and seed vigor was observed. As a result of next-generation sequencing, the molecular markers SilicoDArT (53,031) and SNP (28,571) were obtained. Out of 81,602 identified SilicoDArT and SNP markers, 15,409 (1559 SilicoDArT and 13,850 SNP) were selected as a result of association mapping, which showed them to be significantly related to the analyzed traits. The 890 molecular markers were associated with seed vigor, and 1323 with seed germination. Fifty-six markers (47 SilicoDArT and nine SNP) were significant for both traits. Of these 56 markers, the 20 most significant were selected (five of these markers were significant at the level of 0.001 for seed vigor and at the level of 0.05 for seed germination, another five markers were significant at the level of 0.001 for seed germination and at the level of 0.05 for seed vigor, five markers significant at the level of 0.001 only for seed vigor and five significant at the level of 0.001 only for seed germination also selected). These markers were used for physical mapping to determine their location on the genetic map. Finally, it was found that six of these markers (five silicoDArT2,435,784, 4,772,587, 4,776,334, 2,507,310, 25,981,291, and one SNP2,386,217) are located inside genes, the action of which may affect both seed germination and seed vigor. These markers can be used to select genotypes with high vigor and good seed germination.
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Semillas , Zea mays , Semillas/genética , Germinación/genética , Fitomejoramiento , TecnologíaRESUMEN
In situ extraction is a method for separating plant secondary metabolites from in vitro systems of plant biomass cultures. The study aimed to investigate the MTMS-based xerogels morphology effect on the growth kinetics and deoxyshikonin productivity in xerogel-supported in vitro culture systems of Rindera graeca hairy root. Cultures were supplemented with three types of xerogel, i.e., mesoporous gel, microporous gel, and agglomerated precipitate, in the disintegrated or monolithic form. Structure, oil sorption capacity, and SEM analyses for xerogel-based additives were performed. Application of monolithic macroporous xerogel resulted in the highest biomass proliferation, i.e., 5.11-fold fresh biomass increase after four weeks of the screening culture. The highest deoxyshikonin production (i.e., 105.03 µg) was noted when hairy roots were maintained with particles of disintegrated mesoporous xerogel. The detailed kinetics investigations (6-week culture) revealed the highest growth of hairy root biomass and secondary metabolite production, equaling 9.46-fold fresh weight biomass and 204.08 µg deoxyshikonin, respectively. MTMS-based xerogels have been recognized as selective biocompatible scaffolds for boosting the proliferation of transgenic roots or for productivity enhancement of naphthoquinones without detrimental effects on biomass growth, and their successful applicability in in situ removal of secondary plant metabolites has been experimentally confirmed.
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Boraginaceae , Naftoquinonas , Raíces de Plantas/metabolismo , Naftoquinonas/metabolismo , Plantas/metabolismo , Proliferación CelularRESUMEN
On the basis of studies carried out in the last few years, it is estimated that maize diseases cause yield losses of up to 30% each year. The most dangerous diseases are currently considered to be caused by fungi of the genus Fusarium, which are the main culprits of root rot, ear rots, and stalk rot. Early plant infection causes grain diminution, as well as a significant deterioration in nutritional value and fodder quality due to the presence of harmful mycotoxins. Therefore, the aim of the research was to identify new markers of the SilicoDArT and SNP type, which could be used for the mass selection of varieties resistant to fusarium. The plant material consisted of 186 inbred maize lines. The lines came from experimental plots belonging to two Polish breeding companies: Plant Breeding Smolice Ltd., (Co., Kobylin, Poland). Plant Breeding and Acclimatization Institute-National Research Institute Group (51°41'23.16â³ N, 17°4'18.241â³ E), and Malopolska Plant Breeding Kobierzyce, Poland Ltd., (Co., Kobierzyce, Poland) (50°58'19.411â³ N, 16°55'47.323â³ E). As a result of next-generation sequencing, a total of 81,602 molecular markers were obtained, of which, as a result of the associative mapping, 2962 (321 SilicoDArT and 2641 SNP) significantly related to plant resistance to fusarium were selected. Out of 2962 markers significantly related to plant resistance in the fusarium, seven markers (SilicoDArT, SNP) were selected, which were significant at the level of 0.001. They were used for physical mapping. As a result of the analysis, it was found that two out of seven selected markers (15,097-SilicoDArT and 58,771-SNP) are located inside genes, on chromosomes 2 and 3, respectively. Marker 15,097 is anchored to the gene encoding putrescine N-hydroxycinnamoyltransferase while marker 58,771 is anchored to the gene encoding the peroxidase precursor 72. Based on the literature data, both of these genes may be associated with plant resistance to fusarium. Therefore, the markers 15,097 (SilicoDArT) and 58,771 (SNP) can be used in breeding programs to select lines resistant to fusarium.
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Fusarium , Resistencia a la Enfermedad/genética , Fusarium/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Fitomejoramiento , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Zea mays/genética , Zea mays/microbiologíaRESUMEN
In the last decade, many scientists have used molecular biology methods in their research to locate the grain-yield-determining loci and yield structure characteristics in maize. Large-scale molecular analyses in maize do not only focus on the identification of new markers and quantitative trait locus (QTL) regions. DNA analysis in the selection of parental components for heterotic crosses is a very important tool for breeders. The aim of this research was to identify and select new markers for maize (SNP and SilicoDArT) linked to genes influencing the size of the yield components in maize. The plant material used for the research was 186 inbred maize lines. The field experiment was established in twolocations. The yield and six yield components were analyzed. For identification of SNP and SilicoDArT markers related to the yield and yield components, next-generation sequencing was used. As a result of the biometric measurements analysis, differentiation in the average elevation of the analyzed traits for the lines in both locations was found. The above-mentioned results indicate the existence of genotype-environment interactions. The analysis of variance for the observed quality between genotypes indicated a statistically significant differentiation between genotypes and a statistically significant differentiation for all the observed properties betweenlocations. A canonical variable analysis was applied to present a multi-trait assessment of the similarity of the tested maize genotypes in a lower number of dimensions with the lowest possible loss of information. No grouping of lines due to the analyzed was observed. As a result of next-generation sequencing, the molecular markers SilicoDArT (53,031) and SNP (28,571) were obtained. The genetic distance between the analyzed lines was estimated on the basis of these markers. Out of 81,602 identified SilicoDArT and SNP markers, 15,409 (1559 SilicoDArT and 13,850 SNPs) significantly related to the analyzed yield components were selected as a result of association mapping. The greatest numbers of molecular markers were associated with cob length (1203), cob diameter (1759), core length (1201) and core diameter (2326). From 15,409 markers significantly related to the analyzed traits of the yield components, 18 DArT markers were selected, which were significant for the same four traits (cob length, cob diameter, core length, core diameter) in both Kobierzyce and Smolice. These markers were used for physical mapping. As a result of the analyses, it was found that 6 out of 18 (1818; 14,506; 2317; 3233; 11,657; 12,812) identified markers are located inside genes. These markers are located on chromosomes 8, 9, 7, 3, 5, and 1, respectively.
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Polimorfismo de Nucleótido Simple , Zea mays , Fenotipo , Polimorfismo de Nucleótido Simple/genética , Sitios de Carácter Cuantitativo , Tecnología , Zea mays/genéticaRESUMEN
The response to the pandemic requires access to accurate information and public understanding and adherence to preventive measures. This online cross-sectional study of adult Poles (n = 1337) assessed the frequency of COVID-19 preventive behaviors, fears related to the COVID-19 pandemic, and beliefs in COVID-19-related conspiracy theories during the early phase of the COVID-19 pandemic when the nationwide lockdown was imposed (April 2020). As shown, 22% of surveyed admitted not to wash their hands frequently, while 12% did not use disinfectants. These two behaviors were also less frequent in individuals with medical education. The highest levels of pandemic-related fears were associated with health loss in relatives, pandemic-induced economic crisis, and government using a pandemic to control citizens by the state. A significant share of surveyed individuals believed that the pandemic was intentional action to weaken non-Chinese economies (32%) or was deliberately induced for profits from selling vaccines (27%). Men, individuals with no children, and subjects with lower education were significantly less likely to adhere to sanitary measures (handwashing, disinfection, avoiding face touching, changes in greeting etiquette, face-covering when coughing or sneezing), and were less concerned over self and relatives' health. At the same time, men were less prone than women to the conspiracy theories related to the COVID-19 pandemic. The results indicate that adherence to sanitary measures during the pandemic can be a challenge also in developed countries, while misinformation campaigns (also concerning vaccines) have already affected the general public during the early phase of the epidemiological outbreak. The study provides observations that may be useful in the management of the public response to future epidemics.
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COVID-19 , Pandemias , Adulto , Control de Enfermedades Transmisibles , Comunicación , Estudios Transversales , Miedo , Femenino , Humanos , Masculino , Pandemias/prevención & control , Polonia/epidemiología , SARS-CoV-2RESUMEN
The formation of silica aerogels and the kinetics of condensation were investigated numerically. The influence of the reaction-limited to the diffusion-limited aggregation (RLA to DLA) transition on the reaction kinetics curves and the evolution of the aggregate size distribution during condensation were examined. The 2D cellular automaton was developed and applied to reflect the process of secondary particle aggregation. Several tendencies were observed due to the adjustment of the model parameters: the probability of condensation reaction and the particles' concentration. The final wet-gel structures' visualizations proves that the structure becomes more dense and compact due to entering the RLA regime. The simulation time (associated with the gelation time) decreased along with the increase in both model parameters. The lower the collision probability, the slower reaction becomes, and particles are more likely to penetrate the structure deeper until they finally join the aggregate. The developed model reflects the condensation process's nature and its mechanisms properly and indicates a significant potential for further aerogel synthesis investigations and for the prediction of wet-gel properties according to condensation parameters.
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Unique biosynthetic abilities revealed by plants determine in vitro cultures of hairy roots as a suitable source of pharmaceutically relevant bioactive compounds. The basic aim of the study was to examine the applicability of aerogel composed of methyltrimethoxysilane (MTMS) for immobilization of Rindera graeca hairy roots by identifying quantitative effects of biomass proliferation and naphthoquinones extracellular secretion in the aerogel-supported culture system. R. graeca hairy roots were simultaneously cultured for 28-days, as (i) nonimmobilized biomass (reference system), (ii) biomass immobilized on macroporous polyurethane foam (PUF), (iii) biomass with disintegrated MTMS aerogel, (iv) biomass immobilized on polypropylene (PP) fibers (as control), and (v) biomass immobilized on monolithic PP-reinforced MTMS aerogel. MTMS aerogel exhibited high level of biocompatibility toward R. graeca hairy roots which grew into the structure of monolithic aerogel-based constructs. Monolithic MTMS-based constructs significantly promoted the proliferation of hairy roots, resulting in 55% higher fresh mass than the reference system. The highest level of naphthoquinones productivity, i.e., 653 µg gDW-1, was noted for PUF-supported culture system.
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Huntington's disease (HD) is a genetic disease caused by expanded CAG repeat tract in exon 1 of the HTT gene that codes for huntingtin. Since the first symptoms of the disease the average life expectancy is 15-20 years, when the symptoms resulting from neurodegeneration are progressing. Therefore, there is a great demand for an effective HD treatment method. Various therapeutic strategies are being developed based on mechanisms of gene expression silencing, including DNA editing techniques. Here, we present the most important currently tested approaches, with particular emphasis on strategies based on the use of antisense oligonucleotides (ASO), RNA interference (RNAi) technology and CRISPR-Cas9. Currently ongoing clinical trials as well as different pharmacological agents are discussed.
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Silenciador del Gen , Enfermedad de Huntington/genética , Enfermedad de Huntington/terapia , Humanos , Oligonucleótidos Antisentido/genéticaRESUMEN
Background The control of the coronavirus disease 2019 (COVID-19) pandemic depends on the profound investigation of the virus biology and its consequences. We aimed to analyze the COVID-19 research productivity of authors representing different countries and associations between the number of articles and COVID-19 spread. Methods We retrieved all articles on COVID-19 indexed in PubMed between 31 December 2019 and 30 June 2020. We identified the countries of individual authors' affiliations. We performed the R Spearman rank correlation test between the number of articles with at least one author from a country per one million citizens and Human Development Index (HDI), a number of COVID-19 cases and deaths per one million citizens before 1 July 2020. Results Overall, we identified 27,815 articles, including 18,225 original contributions, 2,449 reviews, and 69 meta-analyses on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The highest productivity characterized the authors coming from China (n = 11,519 articles with at least one author), followed by the United States of America (n = 9,666) and Italy (n = 7,261). The number of articles on COVID-19 associated with HDI (Rs = 0.79), the numbers of cases (Rs = 0.47), and deaths (Rs = 0.46) (all p < 0.001). Conclusions Early COVID-19 researches were most often authored by researchers from highly developed countries and those affected by the rapid initial spread of SARS-CoV-2.
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BACKGROUND: Pull-out tests have been widely applied to orthopaedic devices such as pedicle screws for the last decades. Despite their wide applicability, this particular pedicle screw testing method does not represent the load pattern of implanted vertebrae with the use of pedicle screw spinal constructs. PURPOSE: In the present study a new custom made foam model (Sawbone) of human vertebra and a corresponding load pattern for pedicle screw spinal implant construct were introduced. They allow for the investigation of loosening at the bone-screw interface and constitute an alternative test method to pullout tests. METHODS: The new custom made foam model of human vertebra was developed and made out of biomechanical materials Sawbones in three different variants, including varied density in order to simulate normal, osteopenic, and osteoporotic quality of bone. Mechanical testing methods followed reproducible, non-pull-out loading protocols based originally on the ASTM F- 1717 standard which enables to introduce loosening at the bone-screw interface. RESULTS: The results include the pattern of screw loosening at the bone-screw interface, measured loosening area at the interface, and mechanical parameters characterising bone-screw interface such as initial stiffness and residual displacements. CONCLUSIONS: The new custom made foam model of human vertebra followed by non-pull-out load protocol enabled investigations of the loosening at the bone-screw interface. During the tests a characteristic toggling profile of loosening was found with a significant widening at the tip of the screw for the osteoporotic quality of bone. It was proposed that the model and the corresponding load protocol may extend the current testing methods based on the pull-out testing, leading to the more accurate testing of pedicle screw spinal constructs focused on the bone-implant interface.
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Biomimética , Ensayo de Materiales , Tornillos Pediculares , Falla de Prótesis , Columna Vertebral , Soporte de PesoRESUMEN
Spinocerebellar ataxia type 7 (SCA7) is a human neurodegenerative polyglutamine (polyQ) disease caused by a CAG repeat expansion in the open reading frame of the ATXN7 gene. The allele-selective silencing of mutant transcripts using a repeat-targeting strategy has previously been used for several polyQ diseases. Herein, we demonstrate that the selective targeting of a repeat tract in a mutant ATXN7 transcript by RNA interference is a feasible approach and results in an efficient decrease of mutant ataxin-7 protein in patient-derived cells. Oligonucleotides (ONs) containing specific base substitutions cause the downregulation of the ATXN7 mutant allele together with the upregulation of its normal allele. The A2 ON shows high allele selectivity at a broad range of concentrations and also restores UCHL1 expression, which is downregulated in SCA7.
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For many years, atmospheric mercury has been perceived as a global pollutant. Transport of mercury compounds in the atmosphere and its deposition on the earth's surface is an important issue that requires knowledge regarding the circulation of the various forms of this metal between environmental components. There are many numerical models that can be used to study and image this phenomenon. These models are based on data concerning mercury emission sources, concentrations of this contaminant on modelling areas and meteorological data to assess air mass inflow on a regional and global scale. A method to assess mercury deposition fluxes on a local scale based only on stream intensity analysis of mercury is proposed in this study. Mercury deposition fluxes (bulk) that were assessed by the MDC method at the Zloty Potok station (regional background station for the Silesian Agglomeration) varied from 22.8 µg · m-2 · year-1 (an 8-month period in 2013) to 54.2 µg · m-2 · year-1 in 2012. Developing procedures to estimate the mercury deposition coefficient (MDC) is useful in areas where only meteorological parameters and mercury concentrations in the atmospheric air are measured. The obtained deposition coefficient values enable quantification of a selected pollutant concentration and its potential impact resulting from deposition.
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PURPOSE: This paper addresses the diagnostic idea proposed in [11] to measure the parameter called rate of creep of axillary fold of tissue using modified Harpenden skinfold caliper in order to distinguish normal and edematous tissue. Our simulations are intended to help understanding the creep phenomenon and creep rate parameter as a sensitive indicator of edema existence. The parametric analysis shows the tissue behavior under the external load as well as its sensitivity to changes of crucial hydro-mechanical tissue parameters, e.g., permeability or stiffness. METHODS: The linear viscoelastic and poroelastic models of normal (single phase) and oedematous tissue (twophase: swelled tissue with excess of interstitial fluid) implemented in COMSOL Multiphysics environment are used. Simulations are performed within the range of small strains for a simplified fold geometry, material characterization and boundary conditions. The predicted creep is the result of viscosity (viscoelastic model) or pore fluid displacement (poroelastic model) in tissue. RESULTS: The tissue deformations, interstitial fluid pressure as well as interstitial fluid velocity are discussed in parametric analysis with respect to elasticity modulus, relaxation time or permeability of tissue. The creep rate determined within the models of tissue is compared and referred to the diagnostic idea in [11]. CONCLUSIONS: The results obtained from the two linear models of subcutaneous tissue indicate that the form of creep curve and the creep rate are sensitive to material parameters which characterize the tissue. However, the adopted modelling assumptions point to a limited applicability of the creep rate as the discriminant of oedema.