97 research outputs found

    Relationship of Creative Expression in Early Childhood to Social Acceptance by Peer Groups

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    Family Relations and Child Developmen

    Structural motif screening reveals a novel, conserved carbohydrate-binding surface in the pathogenesis-related protein PR-5d

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    <p>Abstract</p> <p>Background</p> <p>Aromatic amino acids play a critical role in protein-glycan interactions. Clusters of surface aromatic residues and their features may therefore be useful in distinguishing glycan-binding sites as well as predicting novel glycan-binding proteins. In this work, a structural bioinformatics approach was used to screen the Protein Data Bank (PDB) for coplanar aromatic motifs similar to those found in known glycan-binding proteins.</p> <p>Results</p> <p>The proteins identified in the screen were significantly associated with carbohydrate-related functions according to gene ontology (GO) enrichment analysis, and predicted motifs were found frequently within novel folds and glycan-binding sites not included in the training set. In addition to numerous binding sites predicted in structural genomics proteins of unknown function, one novel prediction was a surface motif (W34/W36/W192) in the tobacco pathogenesis-related protein, PR-5d. Phylogenetic analysis revealed that the surface motif is exclusive to a subfamily of PR-5 proteins from the Solanaceae family of plants, and is absent completely in more distant homologs. To confirm PR-5d's insoluble-polysaccharide binding activity, a cellulose-pulldown assay of tobacco proteins was performed and PR-5d was identified in the cellulose-binding fraction by mass spectrometry.</p> <p>Conclusions</p> <p>Based on the combined results, we propose that the putative binding site in PR-5d may be an evolutionary adaptation of Solanaceae plants including potato, tomato, and tobacco, towards defense against cellulose-containing pathogens such as species of the deadly oomycete genus, <it>Phytophthora</it>. More generally, the results demonstrate that coplanar aromatic clusters on protein surfaces are a structural signature of glycan-binding proteins, and can be used to computationally predict novel glycan-binding proteins from 3 D structure.</p

    Evolutionary conservation and post-translational control of S-adenosyl-L-homocysteine hydrolase in land plants

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    Trans-methylation reactions are intrinsic to cellular metabolism in all living organisms. In land plants, a range of substrate-specific methyltransferases catalyze the methylation of DNA, RNA, proteins, cell wall components and numerous species-specific metabolites, thereby providing means for growth and acclimation in various terrestrial habitats. Trans-methylation reactions consume vast amounts of S-adenosyl-L-methionine (SAM) as a methyl donor in several cellular compartments. The inhibitory reaction by-product, S-adenosyl-L-homocysteine (SAH), is continuously removed by SAH hydrolase (SAHH), which essentially maintains trans-methylation reactions in all living cells. Here we report on the evolutionary conservation and post-translational control of SAHH in land plants. We provide evidence suggesting that SAHH forms oligomeric protein complexes in phylogenetically divergent land plants and that the predominant protein complex is composed by a tetramer of the enzyme. Analysis of light-stress-induced adjustments of SAHH in Arabidopsis thaliana and Physcomitrella patens further suggests that regulatory actions may take place on the levels of protein complex formation and phosphorylation of this metabolically central enzyme. Collectively, these data suggest that plant adaptation to terrestrial environments involved evolution of regulatory mechanisms that adjust the trans-methylation machinery in response to environmental cues.Peer reviewe

    PP2A-B’γ modulates foliar trans-methylation capacity and the formation of 4-methoxy-indol-3-yl-methyl glucosinolate in Arabidopsis leaves

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    Glucosinolates (GSL) of cruciferous plants comprise a major group of structurally diverse secondary compounds which act as deterrents against aphids and microbial pathogens and have large commercial and ecological impacts. While the transcriptional regulation governing the biosynthesis and modification of GSL is now relatively well understood, post-translational regulatory components that specifically determine the structural variation of indole glucosinolates have not been reported. We show that the cytoplasmic protein phosphatase 2A regulatory subunit B'gamma (PP2A-B'gamma) physically interacts with indole glucosinolate methyltransferases and controls the methoxylation of indole glucosinolates and the formation of 4-meth-oxy-indol-3-yl-methyl glucosinolate in Arabidopsis leaves. By taking advantage of proteomic approaches and metabolic analysis we further demonstrate that PP2A-B'gamma is required to control the abundance of oligomeric protein complexes functionally linked with the activated methyl cycle and the trans-methylation capacity of leaf cells. These findings highlight the key regulatory role of PP2A-B'gamma in methionine metabolism and provide a previously unrecognized perspective for metabolic engineering of glucosinolate metabolism in cruciferous plants.Peer reviewe

    Measuring older people’s socioeconomic position: a scoping review of studies of self-rated health, health service and social care use

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    Background The challenges of measuring socioeconomic position in older populations were first set out two decades ago. However, the question of how best to measure older people’s socioeconomic position remains pertinent as populations age and health inequalities widen. Methods A scoping review aimed to identify and appraise measures of socioeconomic position used in studies of health inequalities in older populations in high-income countries. Medline, Scopus, EMBASE, HMIC and references lists of systematic reviews were searched for observational studies of socioeconomic health inequalities in adults aged 60 years and over, published between 2000 and 2020. A narrative synthesis was conducted. Findings One-hundred and thirty-eight studies were included; 20 approaches to measuring socioeconomic position were identified. Few studies considered which pathways the chosen measures of socioeconomic position intended to capture. The validity of subjective socioeconomic position measures, and measures that assume shared income and educational capital, should be verified in older populations. Incomplete financial data risk under-representation of some older groups when missing data are socially patterned. Older study samples were largely homogeneous on measures of housing tenure, and to a lesser extent, measures of educational attainment. Measures that use only two response categories risk missing subtle differences in older people’s socioeconomic circumstances. Conclusion Poor choice of measures of socioeconomic position risk underestimating the size of health inequalities in older populations. Choice of measures should be shaped by considerations of theory, context and response categories that detect subtle, yet important, inequalities. Further evidence is required to ascertain the validity of some measures identified in this review

    PP2A-B'γ modulates foliar trans-methylation capacity and the formation of 4-methoxy-indol-3-yl-methyl glucosinolate in Arabidopsis leaves

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    Glucosinolates (GSL) of cruciferous plants comprise a major group of structurally diverse secondary compounds which act as deterrents against aphids and microbial pathogens and have large commercial and ecological impacts. While the transcriptional regulation governing the biosynthesis and modification of GSL is now relatively well understood, post-translational regulatory components that specifically determine the structural variation of indole glucosinolates have not been reported. We show that the cytoplasmic protein phosphatase 2A regulatory subunit B'γ (PP2A-B'γ) physically interacts with indole glucosinolate methyltransferases and controls the methoxylation of indole glucosinolates and the formation of 4-methoxy-indol-3-yl-methyl glucosinolate in Arabidopsis leaves. By taking advantage of proteomic approaches and metabolic analysis we further demonstrate that PP2A-B'γ is required to control the abundance of oligomeric protein complexes functionally linked with the activated methyl cycle and the trans-methylation capacity of leaf cells. These findings highlight the key regulatory role of PP2A-B'γ in methionine metabolism and provide a previously unrecognized perspective for metabolic engineering of glucosinolate metabolism in cruciferous plants.</p

    Non-universal behaviour of helical two-dimensional three-component turbulence

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    The dynamics of two-dimensional three-component (2D3C) flows is relevant to describe the long-time evolution of strongly rotating flows and/or of conducting fluids with a strong mean magnetic field. We show that in the presence of a strong helical forcing, the out-of-plane component ceases to behave as a passive advected quantity and develops a nontrivial dynamics which deeply changes its large-scale properties. We show that a small-scale helicity injection correlates the input on the 2D component with the one on the out-of-plane component. As a result, the third component develops a nontrivial energy transfer. The latter is mediated by homochiral triads, confirming the strong 3D nature of the leading dynamical interactions. In conclusion, we show that the out-of-plane component in a 2D3C flow enjoys strong nonuniversal properties as a function of the degree of mirror symmetry of the small-scale forcing

    Candidate Causal Regulatory Effects by Integration of Expression QTLs with Complex Trait Genetic Associations

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    The recent success of genome-wide association studies (GWAS) is now followed by the challenge to determine how the reported susceptibility variants mediate complex traits and diseases. Expression quantitative trait loci (eQTLs) have been implicated in disease associations through overlaps between eQTLs and GWAS signals. However, the abundance of eQTLs and the strong correlation structure (LD) in the genome make it likely that some of these overlaps are coincidental and not driven by the same functional variants. In the present study, we propose an empirical methodology, which we call Regulatory Trait Concordance (RTC) that accounts for local LD structure and integrates eQTLs and GWAS results in order to reveal the subset of association signals that are due to cis eQTLs. We simulate genomic regions of various LD patterns with both a single or two causal variants and show that our score outperforms SNP correlation metrics, be they statistical (r2) or historical (D'). Following the observation of a significant abundance of regulatory signals among currently published GWAS loci, we apply our method with the goal to prioritize relevant genes for each of the respective complex traits. We detect several potential disease-causing regulatory effects, with a strong enrichment for immunity-related conditions, consistent with the nature of the cell line tested (LCLs). Furthermore, we present an extension of the method in trans, where interrogating the whole genome for downstream effects of the disease variant can be informative regarding its unknown primary biological effect. We conclude that integrating cellular phenotype associations with organismal complex traits will facilitate the biological interpretation of the genetic effects on these traits
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