642 research outputs found
A Common Variant Associated with Dyslexia Reduces Expression of the KIAA0319 Gene
Numerous genetic association studies have implicated the KIAA0319 gene on human chromosome 6p22 in dyslexia susceptibility. The causative variant(s) remains unknown but may modulate gene expression, given that (1) a dyslexia-associated haplotype has been implicated in the reduced expression of KIAA0319, and (2) the strongest association has been found for the region spanning exon 1 of KIAA0319. Here, we test the hypothesis that variant(s) responsible for reduced KIAA0319 expression resides on the risk haplotype close to the gene's transcription start site. We identified seven single-nucleotide polymorphisms on the risk haplotype immediately upstream of KIAA0319 and determined that three of these are strongly associated with multiple reading-related traits. Using luciferase-expressing constructs containing the KIAA0319 upstream region, we characterized the minimal promoter and additional putative transcriptional regulator regions. This revealed that the minor allele of rs9461045, which shows the strongest association with dyslexia in our sample (max p-value = 0.0001), confers reduced luciferase expression in both neuronal and non-neuronal cell lines. Additionally, we found that the presence of this rs9461045 dyslexia-associated allele creates a nuclear protein-binding site, likely for the transcriptional silencer OCT-1. Knocking down OCT-1 expression in the neuronal cell line SHSY5Y using an siRNA restores KIAA0319 expression from the risk haplotype to nearly that seen from the non-risk haplotype. Our study thus pinpoints a common variant as altering the function of a dyslexia candidate gene and provides an illustrative example of the strategic approach needed to dissect the molecular basis of complex genetic traits
Conceptualisations of children’s wellbeing at school: the contribution of recognition theory
A large study in Australian schools aimed to elucidate understandings of ‘wellbeing’ and of factors in school life that contribute to it. Students and teachers understood wellbeing primarily, and holistically, in terms of interpersonal relationships, in contrast to policy documents which mainly focused on ‘problem areas’ such as mental health. The study also drew on recognition theory as developed by the social philosopher Axel Honneth. Results indicate that recognition theory may be useful in understanding wellbeing in schools, and that empirical research in schools may give rise to further questions regarding theory
Impact of sequence variation in the ul128 locus on production of human cytomegalovirus in fibroblast and epithelial cells
The human cytomegalovirus (HCMV) virion envelope contains a complex consisting of glycoproteins gH and gL plus proteins encoded by the UL128 locus (UL128L): pUL128, pUL130, and pUL131A. UL128L is necessary for efficient infection of myeloid, epithelial, and endothelial cells but limits replication in fibroblasts. Consequently, disrupting mutations in UL128L are rapidly selected when clinical isolates are cultured in fibroblasts. In contrast, bacterial artificial chromosome (BAC)-cloned strains TB40-BAC4, FIX, and TR do not contain overt disruptions in UL128L, yet no virus reconstituted from them has been reported to acquire mutations in UL128L in vitro. We performed BAC mutagenesis and reconstitution experiments to test the hypothesis that these strains contain subtle mutations in UL128L that were acquired during passage prior to BAC cloning. Compared to strain Merlin containing wild-type UL128L, all three strains produced higher yields of cell-free virus. Moreover, TB40-BAC4 and FIX spread cell to cell more rapidly than wild-type Merlin in fibroblasts but more slowly in epithelial cells. The differential growth properties of TB40-BAC4 and FIX (but not TR) were mapped to single-nucleotide substitutions in UL128L. The substitution in TB40-BAC4 reduced the splicing efficiency of UL128, and that in FIX resulted in an amino acid substitution in UL130. Introduction of these substitutions into Merlin dramatically increased yields of cell-free virus and increased cell-to-cell spread in fibroblasts but reduced the abundance of pUL128 in the virion and the efficiency of epithelial cell infection. These substitutions appear to represent mutations in UL128L that permit virus to be propagated in fibroblasts while retaining epithelial cell tropism
Autoimmunity-Associated LYP-W620 Does Not Impair Thymic Negative Selection of Autoreactive T Cells.
A C1858T (R620W) variation in the PTPN22 gene encoding the tyrosine phosphatase LYP is a major risk factor for human autoimmunity. LYP is a known negative regulator of signaling through the T cell receptor (TCR), and murine Ptpn22 plays a role in thymic selection. However, the mechanism of action of the R620W variant in autoimmunity remains unclear. One model holds that LYP-W620 is a gain-of-function phosphatase that causes alterations in thymic negative selection and/or thymic output of regulatory T cells (Treg) through inhibition of thymic TCR signaling. To test this model, we generated mice in which the human LYP-W620 variant or its phosphatase-inactive mutant are expressed in developing thymocytes under control of the proximal Lck promoter. We found that LYP-W620 expression results in diminished thymocyte TCR signaling, thus modeling a "gain-of-function" of LYP at the signaling level. However, LYP-W620 transgenic mice display no alterations of thymic negative selection and no anomalies in thymic output of CD4(+)Foxp3(+) Treg were detected in these mice. Lck promoter-directed expression of the human transgene also causes no alteration in thymic repertoire or increase in disease severity in a model of rheumatoid arthritis, which depends on skewed thymic selection of CD4(+) T cells. Our data suggest that a gain-of-function of LYP is unlikely to increase risk of autoimmunity through alterations of thymic selection and that LYP likely acts in the periphery perhaps selectively in regulatory T cells or in another cell type to increase risk of autoimmunity
Quantitative image analysis of protein foam microstructure and its correlation with rheological properties:Egg white foam
Recent advances in software development and machine learning algorithms are revolutionizing the way microstructures are analyzed and quantified in fields like biology and neuroscience. With this, comes an upsurge in the opportunities to apply these tools to study food microstructure to gain a deeper understanding of food structure-function relationships. This article shows how a recently developed deep-learning cellular segmentation algorithm, ‘Cellpose’ can be used to identify foam microstructure for further quantification. It successfully identified the air bubbles in a protein foam matrix, from microscopic images captured on a simple brightfield microscope. The segmentation algorithm allowed further quantification of microstructural parameters of the air phase (bubbles) and of the liquid phase (lamella) of the foams. Egg white foams were made with basic ingredients for meringue and the effect of sugar concentration and acidic conditions were studied. Microstructural parameters were analyzed in relation to the rheological responses of the foams. The underlying microstructural mechanisms governing the changes in the foams' stiffness and linearity of the viscoelastic response are shown. Sugar changes bubble size distribution by thickening liquid egg white, it also shortened the linear response to deformation due to its decreasing lamella thickness. Acidity re-shaped the bubbles into more ‘hexagon-like’ structures allowing more air to be incorporated in the foams. The shape of the bubbles under acidic conditions also makes the foams extend their linear response to deformation. The understanding achieved with data from the algorithm-identified microstructures presents a new way to characterize and study food foams.</p
Gender specific age-related changes in bone density, muscle strength and functional performance in the elderly: a-10 year prospective population-based study
Background: Age-related losses in bone mineral density (BMD), muscle strength, balance, and gait have been linked to an increased risk of falls, fractures and disability, but few prospective studies have compared the timing, rate and pattern of changes in each of these measures in middle-aged and older men and women. This is important so that targeted strategies can be developed to optimise specific musculoskeletal and functional performance measures in older adults. Thus, the aim of this 10-year prospective study was to: 1) characterize and compare age- and gender-specific changes in BMD, grip strength, balance and gait in adults aged 50 years and over, and 2) compare the relative rates of changes between each of these musculoskeletal and functional parameters with ageing.Methods: Men (n = 152) and women (n = 206) aged 50, 60, 70 and 80 years recruited for a population-based study had forearm BMD, grip strength, balance and gait velocity re-assessed after 10-years.Results: The annual loss in BMD was 0.5-0.7% greater in women compared to men aged 60 years and older (p < 0.05- < 0.001), but there were no gender differences in the rate of loss in grip strength, balance or gait. From the age of 50 years there was a consistent pattern of loss in grip strength, while the greatest deterioration in balance and gait occurred from 60 and 70 years onwards, respectively. Comparison of the changes between the different measures revealed that the annual loss in grip strength in men and women aged <70 years was 1-3% greater than the decline in BMD, balance and gait velocity.Conclusion: There were no gender differences in the timing (age) and rate (magnitude) of decline in grip strength, balance or gait in Swedish adults aged 50 years and older, but forearm BMD decreased at a greater rate in women than in men. Furthermore, there was heterogeneity in the rate of loss between the different musculoskeletal and function parameters, especially prior to the age of 70 years, with grip strength deteriorating at a greater rate than BMD, balance and gait.</div
Deletion of the Human Cytomegalovirus US17 Gene Increases the Ratio of Genomes per Infectious Unit and Alters Regulation of Immune and Endoplasmic Reticulum Stress Response Genes at Early and Late Times after Infection
Human cytomegalovirus (HCMV) employs numerous strategies to combat, subvert, or co-opt host immunity. One evolutionary strategy for this involves capture of a host gene and then its successive duplication and divergence, forming a family of genes, many of which have immunomodulatory activities. The HCMV US12 family consists of 10 tandemly arranged sequence-related genes in the unique short (US) region of the HCMV genome (US12 to US21). Each gene encodes a protein possessing seven predicted transmembrane domains, patches of sequence similarity with cellular G-protein-coupled receptors, and the Bax inhibitor 1 family of antiapoptotic proteins. We show that one member, US17, plays an important role during virion maturation. Microarray analysis of cells infected with a recombinant HCMV isolate with a US17 deletion (the ΔUS17 mutant virus) revealed blunted host innate and interferon responses at early times after infection (12 h postinfection [hpi]), a pattern opposite that previously seen in the absence of the immunomodulatory tegument protein pp65 (pUL83). Although the ΔUS17 mutant virus produced numbers of infectious particles in fibroblasts equal to the numbers produced by the parental virus, it produced \u3e3-fold more genome-containing noninfectious viral particles and delivered increased amounts of pp65 to newly infected cells. These results suggest that US17 has evolved to control virion composition, to elicit an appropriately balanced host immune response. At later time points (96 hpi), ΔUS17 mutant-infected cells displayed aberrant expression of several host endoplasmic reticulum stress response genes and chaperones, some of which are important for the final stages of virion assembly and egress. Our results suggest that US17 modulates host pathways to enable production of virions that elicit an appropriately balanced host immune response
Habitat specificity of a threatened and endemic cliff-dwelling halophyte
Research ArticleCoastal areas and other saline environments are major contributors to regional and global biodiversity
patterns. In these environments, rapidly changing gradients require highly specialized plants like halophytes.
In European coastal cliff-tops, rocky and sandy seashores, and saltmarshes, typical halophytes from the genus
Limonium are commonly found. Among them, the aneuploid tetraploid (2n ¼ 4x ¼ 35, 36, 37) Limonium multiflorum,
endemic to the west coast of Portugal, is an interesting case study for investigating the ecology and conservation
of a halophyte agamospermic species. Although it is listed in the IUCN red list of threatened species,
information on its population size or rarity, as well as its ecology, in some respects is still unknown. Field surveys
in the largest known population were performed (Raso cape, Portugal) in order to determine habitat requirements
and conservation status. A total of 88 quadrats were monitored, 43 of which contained at least one L. multiflorum
individual. For each sampled quadrat, four abiotic and four biotic variables as well as two spatially derived variables
were recorded. Principal component analysis and cluster analysis showed narrow habitat specificity for this species
which appeared to be intolerant to competition with invasive alien plants. We conclude that in situ conservation
in a local ‘hotspot’ of this rare and vulnerable species emerges as a priority in order to ensure that biodiversity is not los
Future workshops as a means to democratic, inclusive and empowering research with children, young people and others
Context-dependent signaling defines roles of BMP9 and BMP10 in embryonic and postnatal development
- …
