1,091 research outputs found
The alternate GNB3 splice variant, Gβ3s, exhibits an altered signalling response to EGF stimulation, which leads to enhanced cell migration
It has recently been reported that the duplication of the GNB3 gene has been shown to be directly linked to an obesity phenotype, both in humans and also in a humanised mouse model. Moreover, the common human GNB3 c.825C>T polymorphism (rs5443) causes this ubiquitously expressed gene to be aberrantly spliced approximately 50% of the time leading to the production of both a normal Gβ3 protein and a truncated, possibly less stable subunit, known as Gβ3s. The presence of the GNB3 825T allele has previously been shown to be associated with predisposition to hypertension, obesity, various cancers, Alzheimers, age related cognitive function, erectile dysfunction as well as a marker for pharmacogenetic drug action. Great controversy, however, currently exists as to whether these phenotypes associated with the 825T allele are a) mainly due to the presence of the smaller, possibly more active, Gβ3s subunit or b) merely down to the haploinsufficiency of the normal GNB3 transcript, due to its frequent aberrant splicing. In order to try and address these two conflicting hypothesis, we report on the identification and characterisation of signalling alterations unique to the presence of Gβ3s protein subunit. Moreover we also show the physiological consequences associated with altered signalling, directly induced by the Gβ3s subunit. For this, we used both an EBV transformed lymphoblast cell line homozygote for GNB3 825T/825T (TT) and a stable Gβ3s expressing recombinant COS-7 clone. In both of these cell lines that express the Gβ3s subunit, we found enhanced cytosolic calcium influx upon stimulation with EGF, TGFα and VEGF ligands, as compared to “normal” GNB3 controls with the 825C/825C (CC) genotype. This aberrant calcium influx also led to an increase in ERK, but not AKT1, phosphorylation. Despite the lack of AKT1 activation, we paradoxically observed a significant increase in phosphorylation of its downstream substrates, namely mTOR and p70S6k (KS6B2). Moreover we observed a decrease in phospho FoxO3a only in Gβ3s expressing cells, but not in the “normal” GNB3 (CC) control cell line. The presence of the Gβ3s subunit also appeared to alter the distinct localisation patterns of both Foxo3a and AKT1, while also increasing the colocalisation of mTOR and p70S6K. Subsequent growth factor stimulation studies revealed that EGF treatment, of Gβ3s expressing cells, appeared to cause a significant decrease in cAMP levels, which, in turn resulted in both enhanced caveolin-1a phosphorylation, and an increase in actin stress fibre formation. The identification of these distinct Gβ3s specific signalling alterations were indicative of a more aggressive migratory phenotype. This led us to further investigate and confirm that the presence of the Gβ3s subunit also appears to cause significantly enhanced migration and robust scratch wound healing kinetics, as compared to cells harbouring only the normal copy of the gene. These data therefore present convincing evidence that the Gβ3s subunit is stable, functional and its presence can significantly alter signalling pathways, in different cell types
Coenzyme A-transferase-independent butyrate re-assimilation in Clostridium acetobutylicum - evidence from a mathematical model
The hetero-dimeric CoA-transferase CtfA/B is believed to be crucial for the metabolic transition from acidogenesis to solventogenesis in Clostridium acetobutylicum as part of the industrial-relevant acetone-butanol-ethanol (ABE) fermentation. Here, the enzyme is assumed to mediate re-assimilation of acetate and butyrate during a pH-induced metabolic shift and to faciliate the first step of acetone formation from acetoacetyl-CoA. However, recent investigations using phosphate-limited continuous cultures have questioned this common dogma. To address the emerging experimental discrepancies, we investigated the mutant strain Cac-ctfA398s::CT using chemostat cultures. As a consequence of this mutation, the cells are unable to express functional ctfA and are thus lacking CoA-transferase activity. A mathematical model of the pH-induced metabolic shift, which was recently developed for the wild type, is used to analyse the observed behaviour of the mutant strain with a focus on re-assimilation activities for the two produced acids. Our theoretical analysis reveals that the ctfA mutant still re-assimilates butyrate, but not acetate. Based upon this finding, we conclude that C. acetobutylicum possesses a CoA-tranferase-independent butyrate uptake mechanism that is activated by decreasing pH levels. Furthermore, we observe that butanol formation is not inhibited under our experimental conditions, as suggested by previous batch culture experiments. In concordance with recent batch experiments, acetone formation is abolished in chemostat cultures using the ctfa mutant
Identification of the Photoreceptor Transcriptional Co-Repressor SAMD11 as Novel Cause of Autosomal Recessive Retinitis Pigmentosa
Retinitis pigmentosa (RP), the most frequent form of inherited retinal dystrophy is characterized by progressive photoreceptor degeneration. Many genes have been implicated in RP development, but several others remain to be identified. Using a combination of homozygosity mapping, whole-exome and targeted next-generation sequencing, we found a novel homozygous nonsense mutation in SAMD11 in five individuals diagnosed with adult-onset RP from two unrelated consanguineous Spanish families. SAMD11 is ortholog to the mouse major retinal SAM domain (mr-s) protein that is implicated in CRX-mediated transcriptional regulation in the retina. Accordingly, protein-protein network analysis revealed a significant interaction of SAMD11 with CRX. Immunoblotting analysis confirmed strong expression of SAMD11 in human retina. Immunolocalization studies revealed SAMD11 was detected in the three nuclear layers of the human retina and interestingly differential expression between cone and rod photoreceptors was observed. Our study strongly implicates SAMD11 as novel cause of RP playing an important role in the pathogenesis of human degeneration of photoreceptors.This work was supported by several grants from the Spanish Centre for Biomedical Network Research on Rare Diseases (CIBERER)(06/07/0036), Instituto de Salud Carlos III (ISCIII, Spanish Ministry of Health)/FEDER, including FIS (PI013/00226) and RETICS (RD09/0076/00101 and RD12/0034/0010), Ministry of Economy and Competitiveness (MINECO), including FEDER (BFU2012-36845), and BIO2011-27069, Conselleria de Educació of the Valencia Community (PROMETEOII/2014/025), Spanish National Organization of the Blind (ONCE) and the Spanish Fighting Blindness Foundation (FUNDALUCE). M.C. was sponsored by the Miguel Servet Program for Researchers in the Spanish National Health Service (CP12/03256) and RSA by Sara Borrel Postdoctoral Program (CD12/00676), both from the ISCIII/FEDER. A.A-F. was sponsored by CIBERER, RPC is supported by Fundación Conchita Rábago (FCR), L.C is sponsored by RETICS (RD12/0034/0010) from ISCIII and L.d.S. was supported by CAPES Foundation, Ministry of Education of Brazil
What Does it Mean to be a British Isles Lupus Assessment Group-Based Composite Lupus Assessment Responder? Post Hoc Analysis of 2 Phase 3 Trials
OBJECTIVE: The British Isles Lupus Assessment Group–based Composite Lupus Assessment (BICLA) is a validated global measure of treatment response in systemic lupus erythematosus (SLE) clinical trials. To understand the relevance of BICLA in clinical practice, we investigated relationships between BICLA response and routine SLE assessments, patient-reported outcomes (PROs), and medical resource utilization. METHODS: This was a post hoc analysis of pooled data from the phase III, randomized, placebo-controlled, 52-week TULIP-1 (ClinicalTrials.gov identifier: NCT02446912; n = 457) and TULIP-2 (ClinicalTrials.gov identifier: NCT02446899; n = 362) trials of intravenous anifrolumab (150/300 mg once every 4 weeks) in patients with moderate-to-severe SLE. Changes from baseline to week 52 in clinical assessments, PROs, and medical resource use were compared in BICLA responders versus nonresponders, regardless of treatment assignment. RESULTS: BICLA responders (n = 318) achieved significantly improved outcomes compared with nonresponders (n = 501), including lower flare rates, higher rates of attainment of sustained oral glucocorticoid taper to ≤7.5 mg/day, greater improvements in PROs (Functional Assessment of Chronic Illness Therapy–Fatigue, Short Form 36 Health Survey), and fewer SLE-related hospitalizations/emergency department visits (all nominal P < 0.001). Compared with nonresponders, BICLA responders had greater improvements in global and organ-specific disease activity (Physician’s Global Assessment, SLE Disease Activity Index 2000, Cutaneous Lupus Erythematosus Disease Area and Severity Index Activity, and joint counts; all nominal P < 0.001). BICLA responders had fewer lupus-related serious adverse events than nonresponders. CONCLUSION: BICLA response is associated with clinical benefit in SLE assessments, PROs, and medical resource utilization, confirming its value as a clinical trial end point that is associated with measures important to patient care
Tailoring the Phase in Nanoscale MoTe2Grown by Barrier-Assisted Chemical Vapor Deposition
We employed chemical vapor deposition (CVD) from powder precursors aiming at large-area growth of molybdenum ditelluride (MoTe2) thin films, with controlled allotropic 2H and 1T′ phases. This major outcome entails tuning the parametric conditions of the precursor fluxes during the deposition. Using a physical barrier, we induce a concentration gradient of the Te precursor, thus enabling the control of the flux fluid dynamics and the formation of a Te-rich or Te-poor environment. As a consequence, the allotropic phase repartition in the films turns out to be determined by the barrier-induced Te concentration, as clearly evidenced by statistical Raman scattering investigations. The effect of the physical barrier is also reflected in the shape of the crystallite population and in their log-normal areal distribution pointing out to a homogeneous nucleation mode of the MoTe2 crystals. Our approach shows the selective allotropic phase control in the barrier-assisted CVD deposition of MoTe2 by adjusting the kinetics of the chemical reaction rather than with the use of growth surfactants
Crop type identification and spatial mapping using Sentinel-2 satellite data with focus on field-level information
Accurate monitoring of croplands helps in making decisions (for
insurance claims, crop management and contingency plans) at
the macro-level, especially in drylands where variability in cropping
is very high owing to erratic weather conditions. Dryland
cereals and grain legumes are key to ensuring the food and nutritional
security of a large number of vulnerable populations living
in the drylands. Reliable information on area cultivated to such
crops forms part of the national accounting of food production
and supply in many Asian countries, many of which are employing
remote sensing tools to improve the accuracy of assessments
of cultivated areas. This paper assesses the capabilities and limitations
of mapping cultivated areas in the Rabi (winter) season and
corresponding cropping patterns in three districts characterized
by small-plot agriculture. The study used Sentinel-2 Normalized
Difference Vegetation Index (NDVI) 15-day time-series at 10m
resolution by employing a Spectral Matching Technique (SMT)
approach. The use of SMT is based on the well-studied relationship
between temporal NDVI signatures and crop phenology. The
rabi season in India, dominated by non-rainy days, is best suited
for the application of this method, as persistent cloud cover will
hamper the availability of images necessary to generate clearly
differentiating temporal signatures. Our study showed that the
temporal signatures of wheat, chickpea and mustard are easily
distinguishable, enabling an overall accuracy of 84%, with wheat
and mustard achieving 86% and 94% accuracies, respectively. The
most significant misclassifications were in irrigated areas for mustard
and wheat, in small-plot mustard fields covered by trees and
in fragmented chickpea areas. A comparison of district-wise
national crop statistics and those obtained from this study
revealed a correlation of 96%
Study of Electron Transport in Semiconductor Materials
The Monte Carlo Simulation Technique is described and the technique has been applied to obtain the velocity-field characteristics of different compound semiconductors. The results agree with the available experimental data and with those obtained by Boltzmann Transport Equation analytically
Wireless Body Area Networks for Health-Care Systems
Body Area Network (BAN) development has been driven by pressure to reduce health care costs and by an increased focus on prevention and early risk BANs are highly localized wireless networks that can potentially support a variety of medical applications. Our final paper deals with all aspects involved in Wireless BAN (WBAN) in health care arena
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