Osteogenesis Imperfecta (OI) is a disease with varying severity affecting physical, social and emotional well-being of the child and their family. There is no existing evidence on how the OI population regard their quality of life (QoL). The main aim of this study was to determine how OI impacts on the quality of life and well-being of children and their family. It is the first stage of a larger project to develop a disease specific quality of life measure for children with OI.
Identification of modules of co-regulated genes is a crucial first step towards dissecting the regulatory circuitry underlying biological processes. Co-regulated genes are likely to reveal themselves by showing tight co-expression, for example high correlation of expression profiles across multiple time series data sets. However, numbers of up- or down-regulated genes are often large making it difficult to discriminate between dependent co-expression resulting from co-regulation and independent co-expression. Furthermore, modules of co-regulated genes may only show tight co-expression across a subset of the time series, i.e. show condition-dependent regulation.
G protein-coupled receptors (GPCRs) can interact with regulator of G protein signaling (RGS) proteins. However, the effects of such interactions on signal transduction and their physiological relevance have been largely undetermined. Ligand-bound GPCRs initiate by promoting exchange of GDP for GTP on the G? subunit of heterotrimeric G proteins. Signaling is terminated by hydrolysis of GTP to GDP through intrinsic GTPase activity of the G? subunit, a reaction catalyzed by RGS proteins. Using yeast as a tool to study GPCR signaling in isolation, we define an interaction between the cognate GPCR (Mam2) and RGS (Rgs1), mapping the interaction domains. This reaction tethers Rgs1 at the plasma membrane and is essential for physiological signaling response. In vivo quantitative data inform the development of a kinetic model of the GTPase cycle, which extends previous attempts by including GPCR-RGS interactions. In vivo and in silico data confirm that GPCR-RGS interactions can impose an additional layer of regulation through mediating RGS subcellular localization to compartmentalize RGS activity within a cell, thus highlighting their importance as potential targets to modulate GPCR signaling pathways.
A model is presented describing the gene regulatory network surrounding three similar NAC transcription factors that have roles in Arabidopsis leaf senescence and stress responses. ANAC019, ANAC055 and ANAC072 belong to the same clade of NAC domain genes and have overlapping expression patterns. A combination of promoter DNA/protein interactions identified using yeast 1-hybrid analysis and modelling using gene expression time course data has been applied to predict the regulatory network upstream of these genes. Similarities and divergence in regulation during a variety of stress responses are predicted by different combinations of upstream transcription factors binding and also by the modelling. Mutant analysis with potential upstream genes was used to test and confirm some of the predicted interactions. Gene expression analysis in mutants of ANAC019 and ANAC055 at different times during leaf senescence has revealed a distinctly different role for each of these genes. Yeast 1-hybrid analysis is shown to be a valuable tool that can distinguish clades of binding proteins and be used to test and quantify protein binding to predicted promoter motifs.
P-glycoprotein (Pgp) represents the archetypal mechanism of drug resistance. But Pgp alone cannot expel drugs. A small but growing body of works has demonstrated that the membrane biophysical properties are central to Pgp-mediated drug resistance. For example, a change in the membrane surface pressure is expected to support drug-Pgp interaction. An interesting aspect from these models is that under specific conditions, the membrane is predicted to take over Pgp concerning the mechanism of drug resistance especially when the surface pressure is high enough, at which point drugs remain physically blocked at the membrane level. However it remains to be determined experimentally whether the membrane itself could, on its own, affect drug entry into cells that have been selected by a low concentration of drug and that do not express transporters. We demonstrate here that in the case of the drug doxorubicin, alteration of the surface pressure of membrane leaflets drive drug resistance.
Leaf senescence is an essential developmental process that impacts dramatically on crop yields and involves altered regulation of thousands of genes and many metabolic and signaling pathways, resulting in major changes in the leaf. The regulation of senescence is complex, and although senescence regulatory genes have been characterized, there is little information on how these function in the global control of the process. We used microarray analysis to obtain a high-resolution time-course profile of gene expression during development of a single leaf over a 3-week period to senescence. A complex experimental design approach and a combination of methods were used to extract high-quality replicated data and to identify differentially expressed genes. The multiple time points enable the use of highly informative clustering to reveal distinct time points at which signaling and metabolic pathways change. Analysis of motif enrichment, as well as comparison of transcription factor (TF) families showing altered expression over the time course, identify clear groups of TFs active at different stages of leaf development and senescence. These data enable connection of metabolic processes, signaling pathways, and specific TF activity, which will underpin the development of network models to elucidate the process of senescence.
Studies relating physical activity (PA) to weight gain in children have produced mixed results, although there is some evidence for stronger associations with more intense physical activities. The present study tested the hypothesis that weight gain over one year in 8-10 year olds would be more strongly predicted by moderate and vigorous physical activity (MVPA) than total physical activity (total PA) or sedentary behaviour.
Parental control has been hypothesized to cause weight gain in children by weakening self-regulatory processes. However, most studies that link control with weight have been cross-sectional, and therefore causation is uncertain. It remains possible that parental control is a response to child overweight rather than a cause.
A large proportion of UK children do not reach the recommended levels of physical activity (PA) required for optimum health. Few studies have investigated the psychosocial correlates of objectively measured PA in preadolescents. This study examined child attitudes and parental behaviours as correlates of childrens activity.
This study explored associations between child eating behaviors and maternal feeding practices, specifically testing the hypotheses that maternal "restriction" is associated with having a child with stronger food approach tendencies (eg, overresponsiveness to food), and maternal pressure to eat is associated with having a child with food avoidant tendencies (eg, satiety responsiveness). Five-hundred thirty-one families with 7- to 9-year-old children from schools in London, UK, were invited to take part in the Physical Exercise and Appetite in Children Study (PEACHES). Results are from baseline data of this longitudinal study. Of those invited, 405 gave consent for their child to participate (51.6% male; 48% female). Just over half of the mothers (n=213, 53%) completed the Child Eating Behavior Questionnaire and the Child Feeding Questionnaire for the index child (mean age: 8.3±0.62 years) during the 2006-2007 school year. Children were weighed and measured at school by trained researchers. As predicted, maternal restriction was associated with child food responsiveness (P<0.001), and maternal pressure to eat was associated with child satiety responsiveness (P<0.001), slowness (P=0.03), and fussiness (P=0.01). Child enjoyment of food was associated with lower maternal pressure to eat (P=0.01). All effects were independent of the childs body mass index standard deviation score and sociodemographic factors. Practitioners may find it useful to take an interactional perspective, acknowledging that children both influence and are influenced by their parents feeding practices. This will allow the development of targeted interventions and better parental guidance on managing obesogenic eating behaviors in young children.
People have to pay taxes, and usually they do--even though they would rather not. What determines whether and how much they decide to pay depends on more than a cost-benefit calculation. Results from the literature at the intersection of economics and psychology suggest that many factors are relevant, including peoples perceptions of how the money is being spent, and who (else) is being asked to pay taxes. The results also suggest ways in which government may be able to use framing and various biases to influence payment of and attitudes toward tax. But much remains unknown, including, importantly, the extent to which tax incentives influence behavior.
Chondrocytes possess the capacity to transduce load-induced mechanical stimuli into electrochemical signals. The aim of this study was to functionally characterize an ion channel activated in response to membrane stretch in isolated primary equine chondrocytes. We used patch-clamp electrophysiology to functionally characterize this channel and immunohistochemistry to examine its distribution in articular cartilage. In cell-attached patch experiments, the application of negative pressures to the patch pipette (in the range of 20-200 mmHg) activated ion channel currents in six of seven patches. The mean activated current was 45.9 +/- 1.1 pA (n = 4) at a membrane potential of 33 mV (cell surface area approximately 240 microm(2)). The mean slope conductance of the principal single channels resolved within the total stretch-activated current was 118 +/- 19 pS (n = 6), and reversed near the theoretical potassium equilibrium potential, E(K+), suggesting it was a high-conductance potassium channel. Activation of these high-conductance potassium channels was inhibited by extracellular TEA (K(d) approx. 900 microM) and iberiotoxin (K(d) approx. 40 nM). This suggests that the current was largely carried by BK-like potassium (MaxiK) channels. To further characterize these BK-like channels, we used inside-out patches of chondrocyte membrane: we found these channels to be activated by elevation in bath calcium concentration. Immunohistochemical staining of equine cartilage samples with polyclonal antibodies to the alpha1- and beta1-subunits of the BK channel revealed positive immunoreactivity for both subunits in superficial zone chondrocytes. These experiments support the hypothesis that functional BK channels are present in chondrocytes and may be involved in mechanotransduction and chemotransduction.
The relative reinforcing value (RRV) of food, defined as how hard an individual is prepared to work to gain access to food rather than a nonfood alternative, has been shown to be higher in obese adults and children than in their normal-weight counterparts. However, these cross-sectional studies are unable to determine whether a high RRV of food is predictive of adiposity change or whether it is a consequence of being obese.
G protein-coupled receptors (GPCRs) regulate a variety of intracellular pathways through their ability to promote the binding of GTP to heterotrimeric G proteins. Regulator of G protein signaling (RGS) proteins increases the intrinsic GTPase activity of Galpha-subunits and are widely regarded as negative regulators of G protein signaling. Using yeast we demonstrate that GTP hydrolysis is not only required for desensitization, but is essential for achieving a high maximal (saturated level) response. Thus RGS-mediated GTP hydrolysis acts as both a negative (low stimulation) and positive (high stimulation) regulator of signaling. To account for this we generated a new kinetic model of the G protein cycle where Galpha(GTP) enters an inactive GTP-bound state following effector activation. Furthermore, in vivo and in silico experimentation demonstrates that maximum signaling output first increases and then decreases with RGS concentration. This unimodal, non-monotone dependence on RGS concentration is novel. Analysis of the kinetic model has revealed a dynamic network motif that shows precisely how inclusion of the inactive GTP-bound state for the Galpha produces this unimodal relationship.
Ras homologue enriched in striatum (Rhes) is a small monomeric G protein which functions in a variety of cellular processes, including attenuation of G protein-coupled receptor (GPCR) signalling. There have been many studies into the effects of Rhes, but there is no molecular information about how Rhes might bring about these effects. Rhes shares striking sequence homology to AGS1 (activator of G protein signalling 1) and we considered whether the two proteins function in similar ways. AGS1 binds to the Gbeta1 subunit of heterotrimeric G proteins and we have used yeast two-hybrid studies to show that Rhes binds selectively to Gbeta1, Gbeta2 and Gbeta3 subunits. Binding to the Gbeta subunits involves the cationic regions of AGS1 and Rhes, and we used Rhes-AGS1 chimeras to show that their different cationic regions determine the Gbeta-specificity of the interactions. Possible implications of this interaction for the activity of Rhes are discussed.
Across two studies, we examined the association between adiposity, restrictive feeding practices and cortical processing bias to food stimuli in children. We assessed P3b event-related potential (ERP) during visual oddball tasks in which the frequently presented stimulus was non-food and the infrequently presented stimulus was either a food (Study 1) or non-food (Study 2) item. Children responded to the infrequently presented stimulus and accuracy and speed responses were collected. Restrictive feeding practices, childrens height and weight were also measured. In Study 1, the difference in P3b amplitude for infrequently presented food stimuli, relative to frequently presented non-food stimuli, was negatively associated with adiposity and positively associated with restrictive feeding practices after controlling for adiposity. There was no association between P3b amplitude difference and adiposity or restriction in Study 2, suggesting that the effects seen in Study 1 were not due to general attentional processes. Taken together, our results suggest that attentional salience, as indexed by the P3b amplitude, may be important for understanding the neural correlates of adiposity and restrictive feeding practices in children.
Transcriptional reprogramming forms a major part of a plants response to pathogen infection. Many individual components and pathways operating during plant defense have been identified, but our knowledge of how these different components interact is still rudimentary. We generated a high-resolution time series of gene expression profiles from a single Arabidopsis thaliana leaf during infection by the necrotrophic fungal pathogen Botrytis cinerea. Approximately one-third of the Arabidopsis genome is differentially expressed during the first 48 h after infection, with the majority of changes in gene expression occurring before significant lesion development. We used computational tools to obtain a detailed chronology of the defense response against B. cinerea, highlighting the times at which signaling and metabolic processes change, and identify transcription factor families operating at different times after infection. Motif enrichment and network inference predicted regulatory interactions, and testing of one such prediction identified a role for TGA3 in defense against necrotrophic pathogens. These data provide an unprecedented level of detail about transcriptional changes during a defense response and are suited to systems biology analyses to generate predictive models of the gene regulatory networks mediating the Arabidopsis response to B. cinerea.
The PHYTOCHROME AND FLOWERING TIME1 gene encoding the MEDIATOR25 (MED25) subunit of the eukaryotic Mediator complex is a positive regulator of jasmonate (JA)-responsive gene expression in Arabidopsis (Arabidopsis thaliana). Based on the function of the Mediator complex as a bridge between DNA-bound transcriptional activators and the RNA polymerase II complex, MED25 has been hypothesized to function in association with transcriptional regulators of the JA pathway. However, it is currently not known mechanistically how MED25 functions to regulate JA-responsive gene expression. In this study, we show that MED25 physically interacts with several key transcriptional regulators of the JA signaling pathway, including the APETALA2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) transcription factors OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59 and ERF1 as well as the master regulator MYC2. Physical interaction detected between MED25 and four group IX AP2/ERF transcription factors was shown to require the activator interaction domain of MED25 as well as the recently discovered Conserved Motif IX-1/EDLL transcription activation motif of MED25-interacting AP2/ERFs. Using transcriptional activation experiments, we also show that OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59- and ERF1-dependent activation of PLANT DEFENSIN1.2 as well as MYC2-dependent activation of VEGETATIVE STORAGE PROTEIN1 requires a functional MED25. In addition, MED25 is required for MYC2-dependent repression of pathogen defense genes. These results suggest an important role for MED25 as an integrative hub within the Mediator complex during the regulation of JA-associated gene expression.
Commercial interventions seeking to promote fruit and vegetable consumption by encouraging preschool- and school-aged children to engage with foods with all their senses are increasing in number. We review the efficacy of such sensory interaction programmes and consider the components of these that are likely to encourage food acceptance. Repeated exposure to a foods flavour has robust empirical support in terms of its potential to increase food intake. However, children are naturally reluctant to taste new or disliked foods, and parents often struggle to provide sufficient taste opportunities for these foods to be adopted into the childs diet. We therefore explore whether prior exposure to a new foods non-taste sensory properties, such as its smell, sound, appearance or texture, might facilitate the foods introduction into the childs diet, by providing the child with an opportunity to become partially familiar with the food without invoking the distress associated with tasting it. We review the literature pertaining to the benefits associated with exposure to foods through each of the five sensory modalities in turn. We conclude by calling for further research into the potential for familiarisation with the visual, olfactory, somaesthetic and auditory properties of foods to enhance childrens willingness to consume a variety of fruits and vegetables.
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