Inactivation defects caused by myotonia-associated mutations in the sodium channel III-IV linker.

Missense mutations in the skeletal muscle Na+ channel alpha subunit occur in several heritable forms of myotonia and periodic paralysis. Distinct phenotypes arise from mutations at two sites within the III-IV cytoplasmic loop: myotonia without weakness due to substitutions at glycine 1306, and myotonia plus weakness caused by a mutation at threonine 1313. Heterologous expression in HEK cells showed that substitutions at either site disrupted inactivation, as reflected by slower inactivation rates, shifts in steady-state inactivation, and larger persistent Na+ currents. For T1313M, however, the changes were an order of magnitude larger than any of three substitutions at G1306, and recovery from inactivation was hastened as well. Model simulations demonstrate that these functional difference have distinct phenotypic consequences. In particular, a large persistent Na+ current predisposes to paralysis due to depolarization-induced block of action potential generation

Understanding socioeconomic disparities in breastfeeding in the UK: Exploring the role of environmental quality

Guided by the evolutionary framework of life history theory, which predicts lower parental investment in lower-quality environments, my PhD research explores socioeconomic differentials in breastfeeding behaviour in the UK with a particular focus on local environmental quality. My research is quantitative, and I use advanced statistical techniques to analyse two large UK cohort datasets: the Millennium Cohort Study (MCS) and the Born in Bradford (BiB) cohort. The thesis is comprised of three papers. The first paper compares objective and subjective summary measures of the local environment, using factor analysis to pull together both physical and sociocultural aspects. Using multi-level modelling on nationally-representative data (the MCS), I isolate the effects of the local environment above and beyond that of individual socioeconomic status (SES) and wider-scale deprivation and other ward-level factors such as ethnic composition. I find that objectively-assessed environmental quality is a more robust indicator of breastfeeding initiation and duration than subjectively-assessed environmental quality and also that higher individual socioeconomic status provides a buffer, protecting the breastfeeding chances of those with more resources, even in low quality environments. With Paper 1 providing a UK-wide picture of the relationship between environmental quality and breastfeeding, my second paper zooms in on one geographical region in particular. In Paper 2 I use the BiB dataset, with its largely bi-ethnic Bradford population to look at the influence of the physical environment (e.g. air and water pollution) on breastfeeding outcomes and whether there are differences between White British and Pakistani mothers. I use structural equation modelling to explore whether associations are mediated by birth outcomes. I find the predicted negative association between SES and breastfeeding, but no strong or consistent evidence for the same relationship when physical measures of environmental quality are used. Paper 3 uses both datasets to situate breastfeeding within a wider suite of reproductive behaviours and demographic and health traits including other parental investment measures, menarche and age at first birth and uses latent class analysis to test whether these characteristics cluster together to form identifiable life history strategies along an environmental quality continuum. This thesis examines the local environment in detail, operationalising environmental quality in different ways, to see whether environmental quality is an important driver of the SES-breastfeeding association in the UK. Overall, the thesis findings suggest that individual SES is a stronger predictor of breastfeeding than environmental quality, but that the two are strongly linked, and exert their own independent effects. The effects of the local environment are however complex and depend on which indicators of environmental quality are used. Associations are not driven by individual environmental perception as much as they are by more objective measures of environmental quality. Less perceivable, more physical measures of environmental quality do not explain the SES-breastfeeding association, suggesting that in the UK context at least, sociocultural environmental factors are likely to have an important influence on breastfeeding outcomes. Although exact pathways and mechanisms remain unclear, intervening at the environmental level has the potential to improve breastfeeding behaviour, as well as other health and reproductive outcomes

Mechanism of cellular uptake of genotoxic silica nanoparticles.

Mechanisms for cellular uptake of nanoparticles have important implications for nanoparticulate drug delivery and toxicity. We have explored the mechanism of uptake of amorphous silica nanoparticles of 14 nm diameter, which agglomerate in culture medium to hydrodynamic diameters around 500 nm. In HT29, HaCat and A549 cells, cytotoxicity was observed at nanoparticle concentrations ≥ 1 μg/ml, but DNA damage was evident at 0.1 μg/ml and above. Transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy confirmed entry of the silica particles into A549 cells exposed to 10 μg/ml of nanoparticles. The particles were observed in the cytoplasm but not within membrane bound vesicles or in the nucleus. TEM of cells exposed to nanoparticles at 4°C for 30 minutes showed particles enter cells when activity is low, suggesting a passive mode of entry. Plasma lipid membrane models identified physical interactions between the membrane and the silica NPs. Quartz crystal microbalance experiments on tethered bilayer lipid membrane systems show that the nanoparticles strongly bind to lipid membranes, forming an adherent monolayer on the membrane. Leakage assays on large unilamellar vesicles (400 nm diameter) indicate that binding of the silica NPs transiently disrupts the vesicles which rapidly self-seal. We suggest that an adhesive interaction between silica nanoparticles and lipid membranes could cause passive cellular uptake of the particles

Psychological type and prayer preferences: a study among Anglican clergy in the United Kingdom

This study applies the framework of Jungian psychological type theory to define eight aspects of prayer preference, namely: introverted prayer, extraverted prayer, sensing prayer, intuitive prayer, feeling prayer, thinking prayer, judging prayer, and perceiving prayer. On the basis of data provided by 1,476 newly ordained Anglican clergy from England, Ireland, Scotland, and Wales, eight 7-item scales were developed to access these aspects of prayer preferences. Significant correlations were found between each prayer preference and the relevant aspect of psychological type accessed by the Keirsey Temperament Sorter. These data support the theory that psychological type influences the way in which people pray

Changes in postural syntax characterize sensory modulation and natural variation of C. elegans locomotion

Locomotion is driven by shape changes coordinated by the nervous system through time; thus, enumerating an animal's complete repertoire of shape transitions would provide a basis for a comprehensive understanding of locomotor behaviour. Here we introduce a discrete representation of behaviour in the nematode C. elegans. At each point in time, the worm's posture is approximated by its closest matching template from a set of 90 postures and locomotion is represented as sequences of postures. The frequency distribution of postural sequences is heavy-tailed with a core of frequent behaviours and a much larger set of rarely used behaviours. Responses to optogenetic and environmental stimuli can be quantified as changes in postural syntax: worms show different preferences for different sequences of postures drawn from the same set of templates. A discrete representation of behaviour will enable the use of methods developed for other kinds of discrete data in bioinformatics and language processing to be harnessed for the study of behaviour

Using behavioural insights to increase HIV self-sampling kit returns: a randomized controlled text message trial to improve England's HIV self-sampling service.

OBJECTIVES: The aim of the study was to determine whether behaviourally informed short message service (SMS) primer and reminder messages could increase the return rate of HIV self-sampling kits ordered online. METHODS: The study was a 2 × 2 factorial design randomized control trial. A total of 9585 individuals who ordered a self-sampling kit from www.freetesting.hiv different SMS combinations: 1) standard reminders sent days 3 and 7 after dispatch (control); 2) primer sent 1 day after dispatch plus standard reminders; 3) behavioural insights (BI) reminders (no primer); or 4) primer plus BI reminders. The analysis was restricted to individuals who received all messages (n = 8999). We used logistic regression to investigate independent effects of the primer and BI reminders and their interaction. We explored the impact of sociodemographic characteristics on kit return as a secondary analysis. RESULTS: Those who received the primer and BI reminders had a return rate 4% higher than that of those who received the standard messages. We found strong evidence of a positive effect of the BI reminders (odds ratio 1.13; 95% confidence interval 1.04-1.23; P = 0.003) but no evidence for an effect of the primer, or for an interaction between the two interventions. Odds of kit return increased with age, with those aged ≥ 65 years being almost 2.5 times more likely to return the kit than those aged 25-34 years. Men who have sex with men were 1.5-4.5 times more likely to return the kit compared with other sexual behaviour and gender identity groups. Non-African black clients were 25% less likely to return the kit compared with other ethnicities. CONCLUSIONS: Adding BI to reminder messages was successful in improving return rates at no additional cost

The role of Isocitrate Lyase (ICL1) in the metabolic adaptation of Candida albicans biofilms

Background A major characteristic of Candida biofilm cells that differentiates them from free-floating cells is their high tolerance to antifungal drugs. This high resistance is attributed to particular biofilm properties, including the accumulation of extrapolymeric substances, morphogenetic switching, and metabolic flexibility. Objectives This study evaluated the roles of metabolic processes (in particular the glyoxylate cycle) on biofilm formation, antifungal drug resistance, morphology, and cell wall components. Methods Growth, adhesion, biofilm formation, and cell wall carbohydrate composition were quantified for isogenic Candida albicans ICL1/ICL1, ICL1/icl1, and icl1/icl1 strains. The morphology and topography of these strains were compared by light microscopy and scanning electron microscopy. FKS1 (glucan synthase), ERG11 (14-α-demethylase), and CDR2 (efflux pump) mRNA levels were quantified using qRT-PCR. Results The ICL1/icl1 and icl1/icl1 strains formed similar biofilms and exhibited analogous drug-tolerance levels to the control ICL1/ICL1 strains. Furthermore, the drug sequestration ability of β-1, 3-glucan, a major carbohydrate component of the extracellular matrix, was not impaired. However, the inactivation of ICL1 did impair morphogenesis. ICL1 deletion also had a considerable effect on the expression of the FKS1, ERG11, and CDR2 genes. FKS1 and ERG11 were upregulated in ICL1/icl1 and icl1/icl1 cells throughout the biofilm developmental stages, and CDR2 was upregulated at the early phase. However, their expression was downregulated compared to the control ICL1/ICL1 strain. Conclusions We conclude that the glyoxylate cycle is not a specific determinant of biofilm drug resistance

Selecting low-flammability plants as green firebreaks within sustainable urban garden design

In response to an increasing risk of property loss from wildfires at the urban–wildland interface, there has been growing interest around the world in the plant characteristics of urban gardens that can be manipulated to minimize the chances of property damage or destruction. To date, considerable discussion of this issue can be found in the ‘grey’ literature, covering garden characteristics such as the spatial arrangement of plants in relation to each other, proximity of plants to houses, plant litter and fuel reduction, and the use of low-flammability plants as green firebreaks [1,2,3,4]. Recently, scientific studies from a geographically wide range of fire-prone regions including Europe [5], the USA [6], Australia [7], South Africa [8], and New Zealand [9] have been explicitly seeking to quantify variation among plant species with respect to different aspects of their flammability and to identify low-flammability horticultural species appropriate for implementation as green firebreaks in urban landscapes. The future prospects of this scientific work will ultimately depend on how successfully the results are integrated into the broader context of garden design in fire-prone regions at the urban–wildland interface. Although modern design of urban gardens must consider more than just the issue of green firebreaks, we and others [10,11] believe that selection of low-flammability plants should be high on the priority list of plant selection criteria in fire-prone regions

CLIC1 regulates dendritic cell antigen processing and presentation by modulating phagosome acidification and proteolysis

© 2016, Company of Biologists Ltd. All rights reserved. Intracellular chloride channel protein 1 (CLIC1) participates in inflammatory processes by regulating macrophage phagosomal functions such as pH and proteolysis. Here, we sought to determine if CLIC1 can regulate adaptive immunity by actions on dendritic cells (DCs), the key professional antigen presenting cells. To do this, we first generated bone marrow-derived DCs (BMDCs) from germline CLIC1 gene-deleted (CLIC1-/-) and wild-type (CLIC1+/+) mice, then studied them in vitro and in vivo. We found phagocytosis triggered cytoplasmic CLIC1 translocation to the phagosomal membrane where it regulated phagosomal pH and proteolysis. Phagosomes from CLIC1-/- BMDCs displayed impaired acidification and proteolysis, which could be reproduced if CLIC1+/+, but not CLIC1-/- cells, were treated with IAA94, a CLIC family ion channel blocker. CLIC1-/- BMDC displayed reduced in vitro antigen processing and presentation of full-length myelin oligodendrocyte glycoprotein (MOG) and reduced MOG-induced experimental autoimmune encephalomyelitis. These data suggest that CLIC1 regulates DC phagosomal pH to ensure optimal processing of antigen for presentation to antigen-specific T-cells. Further, they indicate that CLIC1 is a novel therapeutic target to help reduce the adaptive immune response in autoimmune diseases