995 resultados para transfer RNA


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High systemic levels of IP-10 at onset of combination therapy for chronic hepatitis C mirror intrahepatic mRNA levels and predict a slower first phase decline in HCV RNA as well as poor outcome. Recently several genome wide association studies have revealed that single nucleotide polymorphisms (SNPs) on chromosome19 within proximity of IL28B predict spontaneous clearance of HCV infection and as therapeutic outcome among patients infected with HCV genotype 1, with three such SNPs being highly predictive: rs12979860, rs12980275, and rs8099917. In the present study, we correlated genetic variations in these SNPs from 253 Caucasian patients with pretreatment plasma levels of IP-10 and HCV RNA throughout therapy within a phase III treatment trial (HCV-DITTO). The favorable genetic variations in all three SNPs (CC, AA, and TT respectively) was significantly associated with lower baseline IP-10 (CC vs. CT/TT at rs12979860: median 189 vs. 258 pg/mL, P=0.02, AA vs. AG/GG at rs12980275: median 189 vs. 258 pg/mL, P=0.01, TT vs. TG/GG at rs8099917: median 224 vs. 288 pg/mL, P=0.04), were significantly less common among HCV genotype 1 infected patients than genotype 2/3 (P<0.0001, P<0.0001, and P=0.01 respectively) and had significantly higher baseline viral load than carriers of the SNP genotypes (6.3 vs. 5.9 log 10 IU/mL, P=0.0012, 6.3 vs. 6.0 log 10 IU/mL, P=0.026, and 6.3 vs. 5.8 log 10 IU/mL, P=0.0003 respectively). Among HCV genotype 1 infected homozygous or heterogeneous carriers of the favorable C, A, and T genotypes, lower baseline IP-10 was significantly associated with greater decline in HCV-RNA day 0-4, which translated into increased rates of achieving SVR among homozygous patients with baseline IP-10 below 150 pg/mL (85%, 75%, and 75% respectively). In a multivariate analysis among genotype 1 infected patients, both baseline IP-10 and the SNPs were significant independent predictors of SVR. Conclusion: Baseline plasma IP-10 is significantly associated with IL28B variations, and augments the predictiveness of the first phase decline in HCV RNA and final treatment outcome.

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BACKGROUND: Strategies leading to the long-term suppression of inappropriate ocular angiogenesis are required to avoid the need for repetitive monthly injections for treatment of diseases of the eye, such as age-related macular degeneration (AMD). The present study aimed to develop a strategy for the sustained repression of vascular endothelial growth factor (VEGF), which is identified as the key player in exudative AMD. METHODS: We have employed short hairpin (sh)RNAs combined with adeno-associated virus (AAV) delivery to obtain the targeted expression of potent gene-regulatory molecules. Anti-VEGF shRNAs were analyzed in human retinal pigment epithelial (RPE) cells using Renilla luciferase screening. For in vivo delivery of the most potent shRNA, self-complementary AAV vectors were packaged in serotype 8 capsids (scAAV2/8-hU6-sh9). In vivo efficacy was evaluated either by injection of scAAV2/8-hU6-sh9 into murine hind limb muscles or in a laser-induced murine model of choroidal neovascularization (CNV) following scAAV2/8-hU6-sh9 subretinal delivery. RESULTS: Plasmids encoding anti-VEGF shRNAs showed efficient knockdown of human VEGF in RPEs. Intramuscular administration led to localized expression and 91% knockdown of endogenous murine (m)VEGF. Subsequently, the ability of AAV2/8-encoded shRNAs to impair vessel formation was evaluated in the murine model of CNV. In this model, the sizes of the CNV were significantly reduced (up to 48%) following scAAV2/8-hU6-sh9 subretinal delivery. CONCLUSIONS: Using anti-VEGF vectors, we have demonstrated efficient silencing of endogenous mVEGF and showed that subretinal administration of scAAV2/8-hU6-sh9 has the ability to impair vessel formation in an AMD animal model. Thus, AAV-encoded shRNA can be used for the inhibition of neovascularization, leading to the development of sustained anti-VEGF therapy. Copyright © 2012 John Wiley & Sons, Ltd.

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The transcription factors TFIIB, Brf1, and Brf2 share related N-terminal zinc ribbon and core domains. TFIIB bridges RNA polymerase II (Pol II) with the promoter-bound preinitiation complex, whereas Brf1 and Brf2 are involved, as part of activities also containing TBP and Bdp1 and referred to here as Brf1-TFIIIB and Brf2-TFIIIB, in the recruitment of Pol III. Brf1-TFIIIB recruits Pol III to type 1 and 2 promoters and Brf2-TFIIIB to type 3 promoters such as the human U6 promoter. Brf1 and Brf2 both have a C-terminal extension absent in TFIIB, but their C-terminal extensions are unrelated. In yeast Brf1, the C-terminal extension interacts with the TBP/TATA box complex and contributes to the recruitment of Bdp1. Here we have tested truncated Brf2, as well as Brf2/TFIIB chimeric proteins for U6 transcription and for assembly of U6 preinitiation complexes. Our results characterize functions of various human Brf2 domains and reveal that the C-terminal domain is required for efficient association of the protein with U6 promoter-bound TBP and SNAP(c), a type 3 promoter-specific transcription factor, and for efficient recruitment of Bdp1. This in turn suggests that the C-terminal extensions in Brf1 and Brf2 are crucial to specific recruitment of Pol III over Pol II.

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BACKGROUND: This study validates the use of phycoerythrin (PE) and allophycocyanin (APC) for fluorescence energy transfer (FRET) analyzed by flow cytometry. METHODS: FRET was detected when a pair of antibody conjugates directed against two noncompetitive epitopes on the same CD8alpha chain was used. FRET was also detected between antibody conjugate pairs specific for the two chains of the heterodimeric alpha (4)beta(1) integrin. Similarly, the association of T-cell receptor (TCR) with a soluble antigen ligand was detected by FRET when anti-TCR antibody and MHC class I/peptide complexes (&lt;&lt;tetramers&gt;&gt;) were used. RESULTS: FRET efficiency was always less than 10%, probably because of steric effects associated with the size and structure of PE and APC. Some suggestions are given to take into account this and other effects (e.g., donor and acceptor concentrations) for a better interpretation of FRET results obtained with this pair of fluorochromes. CONCLUSIONS: We conclude that FRET assays can be carried out easily with commercially available antibodies and flow cytometers to study arrays of multimolecular complexes.

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BACKGROUND: The genome of Protochlamydia amoebophila UWE25, a Parachlamydia-related endosymbiont of free-living amoebae, was recently published, providing the opportunity to search for genomic islands (GIs). RESULTS: On the residual cumulative G+C content curve, a G+C-rich 19-kb region was observed. This sequence is part of a 100-kb chromosome region, containing 100 highly co-oriented ORFs, flanked by two 17-bp direct repeats. Two identical gly-tRNA genes in tandem are present at the proximal end of this genetic element. Several mobility genes encoding transposases and bacteriophage-related proteins are located within this chromosome region. Thus, this region largely fulfills the criteria of GIs. The G+C content analysis shows that several modules compose this GI. Surprisingly, one of them encodes all genes essential for F-like conjugative DNA transfer (traF, traG, traH, traN, traU, traW, and trbC), involved in sex pilus retraction and mating pair stabilization, strongly suggesting that, similarly to the other F-like operons, the parachlamydial tra unit is devoted to DNA transfer. A close relatedness of this tra unit to F-like tra operons involved in conjugative transfer is confirmed by phylogenetic analyses performed on concatenated genes and gene order conservation. These analyses and that of gly-tRNA distribution in 140 GIs suggest a proteobacterial origin of the parachlamydial tra unit. CONCLUSIONS: A GI of the UWE25 chromosome encodes a potentially functional F-like DNA conjugative system. This is the first hint of a putative conjugative system in chlamydiae. Conjugation most probably occurs within free-living amoebae, that may contain hundreds of Parachlamydia bacteria tightly packed in vacuoles. Such a conjugative system might be involved in DNA transfer between internalized bacteria. Since this system is absent from the sequenced genomes of Chlamydiaceae, we hypothesize that it was acquired after the divergence between Parachlamydiaceae and Chlamydiaceae, when the Parachlamydia-related symbiont was an intracellular bacteria. It suggests that this heterologous DNA was acquired from a phylogenetically-distant bacteria sharing an amoebal vacuole. Since Parachlamydiaceae are emerging agents of pneumonia, this GI might be involved in pathogenicity. In future, conjugative systems might be developed as genetic tools for Chlamydiales.

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In many species, the introduction of double-stranded RNA induces potent and specific gene silencing, referred to as RNA interference. This phenomenon, which is based on targeted degradation of mRNAs and occurs in almost any eukaryote, from trypanosomes to mice including plants and fungi, has sparked general interest from both applied and fundamental standpoints. RNA interference, which is currently used to investigate gene function in a variety of systems, is linked to natural resistance to viruses and transposon silencing, as if it were a primitive immune system involved in genome surveillance. Here, we review the mechanism of RNA interference in post-transcriptional gene silencing, its function in nature, its value for functional genomic analysis, and the modifications and improvements that may make it more efficient and inheritable. We also discuss the future directions of this versatile technique in both fundamental and applied science.

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The ability of pollutants to affect human health is a major concern, justified by the wide demonstration that reproductive functions are altered by endocrine disrupting chemicals. The definition of endocrine disruption is today extended to broader endocrine regulations, and includes activation of metabolic sensors, such as the peroxisome proliferator-activated receptors (PPARs). Toxicology approaches have demonstrated that phthalate plasticizers can directly influence PPAR activity. What is now missing is a detailed molecular understanding of the fundamental basis of endocrine disrupting chemical interference with PPAR signaling. We thus performed structural and functional analyses that demonstrate how monoethyl-hexyl-phthalate (MEHP) directly activates PPARgamma and promotes adipogenesis, albeit to a lower extent than the full agonist rosiglitazone. Importantly, we demonstrate that MEHP induces a selective activation of different PPARgamma target genes. Chromatin immunoprecipitation and fluorescence microscopy in living cells reveal that this selective activity correlates with the recruitment of a specific subset of PPARgamma coregulators that includes Med1 and PGC-1alpha, but not p300 and SRC-1. These results highlight some key mechanisms in metabolic disruption but are also instrumental in the context of selective PPAR modulation, a promising field for new therapeutic development based on PPAR modulation.

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Machado-Joseph disease or Spinocerebellar ataxia type 3 is a progressive fatal neurodegenerative disorder caused by the polyglutamine-expanded protein ataxin-3. Recent studies demonstrate that RNA interference is a promising approach for the treatment of Machado-Joseph disease. However, whether gene silencing at an early time-point is able to prevent the appearance of motor behavior deficits typical of the disease when initiated before onset of the disease had not been explored. Here, using a lentiviral-mediated allele-specific silencing of mutant ataxin-3 in an early pre-symptomatic cerebellar mouse model of Machado-Joseph disease we show that this strategy hampers the development of the motor and neuropathological phenotypic characteristics of the disease. At the histological level, the RNA-specific silencing of mutant ataxin-3 decreased formation of mutant ataxin-3 aggregates, preserved Purkinje cell morphology and expression of neuronal markers while reducing cell death. Importantly, gene silencing prevented the development of impairments in balance, motor coordination, gait and hyperactivity observed in control mice. These data support the therapeutic potential of RNA interference for Machado-Joseph disease and constitute a proof of principle of the beneficial effects of early allele-specific silencing for therapy of this disease.

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In this paper are described the results of a research project that had the objective of developing construction procedures for restoring load transfer in existing jointed concrete pavements and of evaluating the effectiveness of the restoration methods. A total of 28 test sections with various load transfer devices were placed. The devices include split pipe, figure eight, vee, double vee, and dowel bars. Patching materials used on the project included three types of fast-setting grouts, three brands of polymer concrete, and plain portland cement concrete. The number and spacing of the devices and dowel bars were also variables in the project. Dowel bars and double vee devices were used on the major portion of the project. Performance evaluations were based on deflection tests conducted with a 20,000-lb axle load. Horizontal joint movement measurements and visual observations were also made. The short-term performance data indicate good results with the dowel bar installations regardless of patching materials. The sections with split pipe, figure eight, and vee devices failed in bond during the first winter cycle. The results with the double vee sections indicate the importance of the patching material to the success or failure of the load transfer system: some sections are performing well and other sections are performing poorly with double vee devices. Horizontal joint movement measurements indicate that neither the dowel bars nor the double vee devices are restricting joint movement.

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The efficacy and safety of anti-infective treatments are associated with the drug blood concentration profile, which is directly correlated with a dosing adjustment to the individual patient's condition. Dosing adjustments to the renal function recommended in reference books are often imprecise and infrequently applied in clinical practice. The recent generalisation of the KDOQI (Kidney Disease Outcome Quality Initiative) staging of chronically impaired renal function represents an opportunity to review and refine the dosing recommendations in patients with renal insufficiency. The literature has been reviewed and compared to a predictive model of the fraction of drug cleared by the kidney based on the Dettli's principle. Revised drug dosing recommendations integrating these predictive parameters are proposed.

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We investigated a new procedure for gene transfer into the stroma of pig cornea for the delivery of therapeutic factors. A delimited space was created at 110 mum depth with a LDV femtosecond laser in pig corneas, and a HIV1-derived lentiviral vector expressing green fluorescent protein (GFP) (LV-CMV-GFP) was injected into the pocket. Corneas were subsequently dissected and kept in culture as explants. After 5 days, histological analysis of the explants revealed that the corneal pockets had closed and that the gene transfer procedure was efficient over the whole pocket area. Almost all the keratocytes were transduced in this area. Vector diffusion at right angles to the pocket's plane encompasses four (endothelium side) to 10 (epithelium side) layers of keratocytes. After 21 days, the level of transduction was similar to the results obtained after 5 days. The femtosecond laser technique allows a reliable injection and diffusion of lentiviral vectors to efficiently transduce stromal cells in a delimited area. Showing the efficacy of this procedure in vivo could represent an important step toward treatment or prevention of recurrent angiogenesis of the corneal stroma.

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The use of herbicides in agriculture may lead to environmental problems, such as surface water pollution, with a potential risk for aquatic organisms. The herbicide glyphosate is the most used active ingredient in the world and in Switzerland. In the Lavaux vineyards it is nearly the only molecule applied. This work aimed at studying its fate in soils and its transfer to surface waters, using a multi-scale approach: from molecular (10-9 m) and microscopic scales (10-6 m), to macroscopic (m) and landscape ones (103 m). First of all, an analytical method was developed for the trace level quantification of this widely used herbicide and its main by-product, aminomethylphosphonic acid (AMPA). Due to their polar nature, their derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) was done prior to their concentration and purification by solid phase extraction. They were then analyzed by ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The method was tested in different aqueous matrices with spiking tests and validated for the matrix effect correction in relevant environmental samples. Calibration curves established between 10 and 1000ng/l showed r2 values above 0.989, mean recoveries varied between 86 and 133% and limits of detection and quantification of the method were as low as 5 and 10ng/l respectively. At the parcel scale, two parcels of the Lavaux vineyard area, located near the Lutrive River at 6km to the east of Lausanne, were monitored to assess to which extent glyphosate and AMPA were retained in the soil or exported to surface waters. They were equipped at their bottom with porous ceramic cups and runoff collectors, which allowed retrieving water samples for the growing seasons 2010 and 2011. Results revealed that the mobility of glyphosate and AMPA in the unsaturated zone was likely driven by the precipitation regime and the soil characteristics, such as slope, porosity structure and layer permeability discrepancy. Elevated glyphosate and AMPA concentrations were measured at 60 and 80 cm depth at parcel bottoms, suggesting their infiltration in the upper parts of the parcels and the presence of preferential flow in the studied parcels. Indeed, the succession of rainy days induced the gradual saturation of the soil porosity, leading to rapid infiltration through macropores, as well as surface runoff formation. Furthermore, the presence of more impervious weathered marls at 100 cm depth induced throughflows, the importance of which for the lateral transport of the herbicide molecules was determined by the slope steepness. Important rainfall events (>10 mm/day) were clearly exporting molecules from the soil top layer, as indicated by important concentrations in runoff samples. A mass balance showed that total loss (10-20%) mainly occurred through surface runoff (96%) and, to a minor extent, by throughflows in soils (4%), with subsequent exfiltration to surface waters. Observations made in the Lutrive River revealed interesting details of glyphosate and AMPA dynamics in urbanized landscapes, such as the Lavaux vineyards. Indeed, besides their physical and chemical properties, herbicide dynamics at the catchment level strongly depend on application rates, precipitation regime, land use and also on the presence of drains or constructed channels. Elevated concentrations, up to 4970 ng/l, observed just after the application, confirmed the diffuse export of these compounds from the vineyard area by surface runoff during main rain events. From April to September 2011, a total load of 7.1 kg was calculated, with 85% coming from vineyards and minor urban sources and 15% from arable crops. Small vineyard surfaces could generate high concentrations of herbicides and contribute considerably to the total load calculated at the outlet, due to their steep slopes (~10%). The extrapolated total amount transferred yearly from the Lavaux vineyards to the Lake of Geneva was of 190kg. At the molecular scale, the possible involvement of dissolved organic matter (DOM) in glyphosate and copper transport was studied using UV/Vis fluorescence spectroscopy. Combined with parallel factor (PARAFAC) analysis, this technique allowed characterizing DOM of soil and surface water samples from the studied vineyard area. Glyphosate concentrations were linked to the fulvic-like spectroscopic signature of DOM in soil water samples, as well as to copper, suggesting the formation of ternary complexes. In surface water samples, its concentrations were also correlated to copper ones, but not in a significant way to the fulvic-like signature. Quenching experiments with standards confirmed field tendencies in the laboratory, with a stronger decrease in fluorescence intensity for fulvic-like fluorophore than for more aromatic ones. Lastly, based on maximum concentrations measured in the river, an environmental risk for these compounds was assessed, using laboratory tests and ecotoxicity data from the literature. In our case and with the methodology applied, the risk towards aquatic species was found negligible (RF<1).

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In jointed portland cement concrete pavements, dowel bars are typically used to transfer loads between adjacent slabs. A common practice is for designers to place dowel bars at a certain, consistent spacing such that a sufficient number of dowels are available to effectively transfer anticipated loads. In many cases, however, the standards developed today for new highway construction simply do not reflect the design needs of low traffic volume, rural roads. The objective of this research was to evaluate the impact of the number of dowel bars and dowel location on joint performance and ultimately on pavement performance. For this research, test sections were designed, constructed, and tested in actual field service pavement. Test sections were developed to include areas with load transfer assemblies having three and four dowels in the outer wheel path only, areas with no joint reinforcement whatsoever, and full lane dowel basket assemblies as the control. Two adjacent paving projects provided both rural and urban settings and differing base materials. This report documents the approach to implementing the study and provides discussion and suggestions based on the results of the research. The research results indicate that the use of single three or four dowel basket assemblies in the outer wheel path is acceptable for use in low truck volume roads. In the case of roadways with relatively stiff bases such as asphalt treated or stabilized bases, the use of the three dowel bar pattern in the outside wheel path is expected to provide adequate performance over the design life of the pavement. In the case of untreated or granular bases, the results indicate that the use of the three or four dowel bar basket in both wheel paths provides the best long-term solution to load transfer and faulting measurements.

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Abstract Bacterial genomes evolve through mutations, rearrangements or horizontal gene transfer. Besides the core genes encoding essential metabolic functions, bacterial genomes also harbour a number of accessory genes acquired by horizontal gene transfer that might be beneficial under certain environmental conditions. The horizontal gene transfer contributes to the diversification and adaptation of microorganisms, thus having an impact on the genome plasticity. A significant part of the horizontal gene transfer is or has been facilitated by genomic islands (GEIs). GEIs are discrete DNA segments, some of which are mobile and others which are not, or are no longer mobile, which differ among closely related strains. A number of GEIs are capable of integration into the chromosome of the host, excision, and transfer to a new host by transformation, conjugation or transduction. GEIs play a crucial role in the evolution of a broad spectrum of bacteria as they are involved in the dissemination of variable genes, including antibiotic resistance and virulence genes leading to generation of hospital 'superbugs', as well as catabolic genes leading to formation of new metabolic pathways. Depending on the composition of gene modules, the same type of GEIs can promote survival of pathogenic as well as environmental bacteria.