443 research outputs found
On the curvature of vortex moduli spaces
We use algebraic topology to investigate local curvature properties of the
moduli spaces of gauged vortices on a closed Riemann surface. After computing
the homotopy type of the universal cover of the moduli spaces (which are
symmetric powers of the surface), we prove that, for genus g>1, the holomorphic
bisectional curvature of the vortex metrics cannot always be nonnegative in the
multivortex case, and this property extends to all Kaehler metrics on certain
symmetric powers. Our result rules out an established and natural conjecture on
the geometry of the moduli spaces.Comment: 25 pages; final version, to appear in Math.
Location of chlorogenic acid biosynthesis pathway and polyphenol oxidase genes in a new interspecific anchored linkage map of eggplant
© Gramazio et al.; licensee BioMed Central. 2014. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated
A PSTOL-like gene, TaPSTOL, controls a number of agronomically important traits in wheat
Background
Phosphorus (P) is an essential macronutrient for plant growth, and is required in large quantities by elite varieties of crops to maintain yields. Approximately 70% of global cultivated land suffers from P deficiency, and it has recently been estimated that worldwide P resources will be exhausted by the end of this century, increasing the demand for crops more efficient in their P usage. A greater understanding of how plants are able to maintain yield with lower P inputs is, therefore, highly desirable to both breeders and farmers. Here, we clone the wheat (Triticum aestivum L.) homologue of the rice PSTOL gene (OsPSTOL), and characterize its role in phosphate nutrition plus other agronomically important traits.
Results
TaPSTOL is a single copy gene located on the short arm of chromosome 5A, encoding a putative kinase protein, and shares a high level of sequence similarity to OsPSTOL. We re-sequenced TaPSTOL from 24 different wheat accessions and (3) three T. durum varieties. No sequence differences were detected in 26 of the accessions, whereas two indels were identified in the promoter region of one of the durum wheats. We characterised the expression of TaPSTOL under different P concentrations and demonstrated that the promoter was induced in root tips and hairs under P limiting conditions. Overexpression and RNAi silencing of TaPSTOL in transgenic wheat lines showed that there was a significant effect upon root biomass, flowering time independent of P treatment, tiller number and seed yield, correlating with the expression of TaPSTOL. However this did not increase PUE as elevated P concentration in the grain did not correspond to increased yields.
Conclusions
Manipulation of TaPSTOL expression in wheat shows it is responsible for many of the previously described phenotypic advantages as OsPSTOL except yield. Furthermore, we show TaPSTOL contributes to additional agronomically important traits including flowering time and grain size. Analysis of TaPSTOL sequences from a broad selection of wheat varieties, encompassing 91% of the genetic diversity in UK bread wheat, showed that there is very little genetic variation in this gene, which would suggest that this locus may have been under high selection pressure
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The identification of QTL controlling ergot sclerotia size in hexaploid wheat implicates a role for the Rht dwarfing alleles
The fungal pathogen Claviceps purpurea infects ovaries of a broad range of temperate grasses and cereals, including hexaploid wheat, causing a disease commonly known as ergot. Sclerotia produced in place of seed carry a cocktail of harmful alkaloid compounds that result in a range of symptoms in humans and animals, causing ergotism. Following a field assessment of C. purpurea infection in winter wheat, two varieties ‘Robigus’ and ‘Solstice’ were selected which consistently produced the largest differential effect on ergot sclerotia weights. They were crossed to produce a doubled haploid mapping population, and a marker map, consisting of 714 genetic loci and a total length of 2895 cM was produced. Four ergot reducing QTL were identified using both sclerotia weight and size as phenotypic parameters; QCp.niab.2A and QCp.niab.4B being detected in the wheat variety ‘Robigus’, and QCp.niab.6A and QCp.niab.4D in the variety ‘Solstice’. The ergot resistance QTL QCp.niab.4B and QCp.niab.4D peaks mapped to the same markers as the known reduced height (Rht) loci on chromosomes 4B and 4D, Rht-B1 and Rht-D1, respectively. In both cases, the reduction in sclerotia weight and size was associated with the semi-dwarfing alleles, Rht-B1b from ‘Robigus’ and Rht-D1b from ‘Solstice’. Two-dimensional, two-QTL scans identified significant additive interactions between QTL QCp.niab.4B and QCp.niab.4D, and between QCp.niab.2A and QCp.niab.4B when looking at sclerotia size, but not between QCp.niab.2A and QCp.niab.4D. The two plant height QTL, QPh.niab.4B and QPh.niab.4D, which mapped to the same locations as QCp.niab.4B and QCp.niab.4D, also displayed significant genetic interactions
Recovery of a temperate reef assemblage in a marine protected area following the exclusion of towed demersal fishing.
Marine Protected Areas MPA have been widely used over the last 2 decades to address human impacts on marine habitats within an ecosystem management context. Few studies have quantified recovery of temperate rocky reef communities following the cessation of scallop dredging or demersal trawling. This is critical information for the future management of these habitats to contribute towards conservation and fisheries targets. The Lyme Bay MPA, in south west UK, has excluded towed demersal fishing gear from 206 km(2) of sensitive reef habitat using a Statutory Instrument since July 2008. To assess benthic recovery in this MPA we used a flying video array to survey macro epi-benthos annually from 2008 to 2011. 4 treatments (the New Closure, previously voluntarily Closed Controls and Near or Far Open to fishing Controls) were sampled to test a recovery hypothesis that was defined as 'the New Closure becoming more similar to the Closed Controls and less similar to the Open Controls'. Following the cessation of towed demersal fishing, within three years positive responses were observed for species richness, total abundance, assemblage composition and seven of 13 indicator taxa. Definitive evidence of recovery was noted for species richness and three of the indicator taxa (Pentapora fascialis, Phallusia mammillata and Pecten maximus). While it is hoped that MPAs, which exclude anthropogenic disturbance, will allow functional restoration of goods and services provided by benthic communities, it is an unknown for temperate reef systems. Establishing the likely timescales for restoration is key to future marine management. We demonstrate the early stages of successful recruitment and link these to the potential wider ecosystem benefits including those to commercial fisheries
The effector T cell response to influenza infection
Influenza virus infection induces a potent initial innate immune response, which serves to limit the extent of viral replication and virus spread. However, efficient (and eventual) viral clearance within the respiratory tract requires the subsequent activation, rapid proliferation, recruitment, and expression of effector activities by the adaptive immune system, consisting of antibody producing B cells and influenza-specific T lymphocytes with diverse functions. The ensuing effector activities of these T lymphocytes ultimately determine (along with antibodies) the capacity of the host to eliminate the viruses and the extent of tissue damage. In this review, we describe this effector T cell response to influenza virus infection. Based on information largely obtained in experimental settings (i.e., murine models), we will illustrate the factors regulating the induction of adaptive immune T cell responses to influenza, the effector activities displayed by these activated T cells, the mechanisms underlying the expression of these effector mechanisms, and the control of the activation/differentiation of these T cells, in situ, in the infected lungs
Increasing vegetable intakes: rationale and systematic review of published interventions
Purpose
While the health benefits of a high fruit and vegetable consumption are well known and considerable work has attempted to improve intakes, increasing evidence also recognises a distinction between fruit and vegetables, both in their impacts on health and in consumption patterns. Increasing work suggests health benefits from a high consumption specifically of vegetables, yet intakes remain low, and barriers to increasing intakes are prevalent making intervention difficult. A systematic review was undertaken to identify from the published literature all studies reporting an intervention to increase intakes of vegetables as a distinct food group.
Methods
Databases—PubMed, PsychInfo and Medline—were searched over all years of records until April 2015 using pre-specified terms.
Results
Our searches identified 77 studies, detailing 140 interventions, of which 133 (81 %) interventions were conducted in children. Interventions aimed to use or change hedonic factors, such as taste, liking and familiarity (n = 72), use or change environmental factors (n = 39), use or change cognitive factors (n = 19), or a combination of strategies (n = 10). Increased vegetable acceptance, selection and/or consumption were reported to some degree in 116 (83 %) interventions, but the majority of effects seem small and inconsistent.
Conclusions
Greater percent success is currently found from environmental, educational and multi-component interventions, but publication bias is likely, and long-term effects and cost-effectiveness are rarely considered. A focus on long-term benefits and sustained behaviour change is required. Certain population groups are also noticeably absent from the current list of tried interventions
Molecular bases of diabetic nephropathy
The determinant of the diabetic nephropathy is hyperglycemia, but hypertension and other genetic factors are also involved. Glomerulus is the focus of the injury, where mesangial cell proliferation and extracellular matrix occur because of the increase of the intra- and extracellular glucose concentration and overexpression of GLUT1. Sequentially, there are increases in the flow by the poliol pathway, oxidative stress, increased intracellular production of advanced glycation end products (AGEs), activation of the PKC pathway, increase of the activity of the hexosamine pathway, and activation of TGF-beta1. High glucose concentrations also increase angiotensin II (AII) levels. Therefore, glucose and AII exert similar effects in inducing extracellular matrix formation in the mesangial cells, using similar transductional signal, which increases TGF-beta1 levels. In this review we focus in the effect of glucose and AII in the mesangial cells in causing the events related to the genesis of diabetic nephropathy. The alterations in the signal pathways discussed in this review give support to the observational studies and clinical assays, where metabolic and antihypertensive controls obtained with angiotensin-converting inhibitors have shown important and additive effect in the prevention of the beginning and progression of diabetic nephropathy. New therapeutic strategies directed to the described intracellular events may give future additional benefits.O principal determinante da nefropatia diabética é a hiperglicemia, mas hipertensão e fatores genéticos também estão envolvidos. O glomérulo é o foco de lesão, onde proliferação celular mesangial e produção excessiva de matriz extracelular decorrem do aumento da glicose intracelular, por excesso de glicose extracelular e hiperexpressão de GLUT1. Seguem-se aumento do fluxo pela via dos polióis, estresse oxidativo intracelular, produção intracelular aumentada de produtos avançados da glicação não enzimática (AGEs), ativação da via da PKC, aumento da atividade da via das hexosaminas e ativação de TGF-beta1. Altas concentrações de glicose também aumentam angiotensina II (AII) nas células mesangiais por aumento intracelular da atividade da renina (ações intrácrinas, mediando efeitos proliferativos e inflamatórios diretamente). Portanto, glicose e AII exercem efeitos proliferativos celulares e de matriz extracelular nas células mesangiais, utilizando vias de transdução de sinais semelhantes, que levam a aumento de TGF-beta1. Nesse estudo são revisadas as vias que sinalizam os efeitos da glicose e AII nas células mesangiais em causar os eventos-chaves relacionados à gênese da glomerulopatia diabética. As alterações das vias de sinalização implicadas na glomerulopatia, aqui revisadas, suportam dados de estudos observacionais/ensaios clínicos, onde controle metabólico e anti-hipertensivo, especificamente com inibidores do sistema renina-angiotensina, têm-se mostrado importantes - e aditivos - na prevenção do início e progressão da nefropatia. Novas estratégias terapêuticas dirigidas aos eventos intracelulares descritos deverão futuramente promover benefício adicional.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)HC Instituto do Coração Unidade de HipertensãoUSP FMUniversidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Laboratório de NefrologiaFundação Universitária de Cardiologia Instituto de Cardiologia Laboratório de Cardiologia Molecular e CelularUNIFESP, EPM, Laboratório de NefrologiaSciEL
Comprehensive and Integrated Genomic Characterization of Adult Soft Tissue Sarcomas
Summary
Sarcomas are a broad family of mesenchymal malignancies exhibiting remarkable histologic diversity. We describe the multi-platform molecular landscape of 206 adult soft tissue sarcomas representing 6 major types. Along with novel insights into the biology of individual sarcoma types, we report three overarching findings: (1) unlike most epithelial malignancies, these sarcomas (excepting synovial sarcoma) are characterized predominantly by copy-number changes, with low mutational loads and only a few genes (TP53, ATRX, RB1) highly recurrently mutated across sarcoma types; (2) within sarcoma types, genomic and regulomic diversity of driver pathways defines molecular subtypes associated with patient outcome; and (3) the immune microenvironment, inferred from DNA methylation and mRNA profiles, associates with outcome and may inform clinical trials of immune checkpoint inhibitors. Overall, this large-scale analysis reveals previously unappreciated sarcoma-type-specific changes in copy number, methylation, RNA, and protein, providing insights into refining sarcoma therapy and relationships to other cancer types
Integrated genomic characterization of oesophageal carcinoma
Oesophageal cancers are prominent worldwide; however, there are few targeted therapies and survival rates for these cancers remain dismal. Here we performed a comprehensive molecular analysis of 164 carcinomas of the oesophagus derived from Western and Eastern populations. Beyond known histopathological and epidemiologic distinctions, molecular features differentiated oesophageal squamous cell carcinomas from oesophageal adenocarcinomas. Oesophageal squamous cell carcinomas resembled squamous carcinomas of other organs more than they did oesophageal adenocarcinomas. Our analyses identified three molecular subclasses of oesophageal squamous cell carcinomas, but none showed evidence for an aetiological role of human papillomavirus. Squamous cell carcinomas showed frequent genomic amplifications of CCND1 and SOX2 and/or TP63, whereas ERBB2, VEGFA and GATA4 and GATA6 were more commonly amplified in adenocarcinomas. Oesophageal adenocarcinomas strongly resembled the chromosomally unstable variant of gastric adenocarcinoma, suggesting that these cancers could be considered a single disease entity. However, some molecular features, including DNA hypermethylation, occurred disproportionally in oesophageal adenocarcinomas. These data provide a framework to facilitate more rational categorization of these tumours and a foundation for new therapies.ope
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