Substrate polyspecificity and conformational relevance in ABC transporters: new insights from structural studies

Transport of molecules and ions across biological membranes is an essential process in all organisms. It is carried out by a range of evolutionarily conserved primary and secondary transporters. A significant portion of the primary transporters belong to the ATP-binding cassette (ABC) superfamily, which utilise the free-energy from ATP hydrolysis to shuttle many different substrates across various biological membranes, and consequently, are involved in both normal and abnormal physiology. In humans, ABC transporter-associated pathologies are perhaps best exemplified by multidrug-resistance transporters that efflux many xenobiotic compounds due to their remarkable substrate polyspecificity. Accordingly, understanding the transport mechanism(s) is of great significance, and indeed, much progress has been made in recent years, particularly from structural studies on ABC exporters. Consequently, the general mechanism of 'alternate access' has been modified to describe individual transporter nuances, though some aspects of the transport process remain unclear. Moreover, as new information has emerged, the physiological relevance of the 'open-apo' conformation of MsbA (a bacterial exporter) has been questioned and, by extension, its contribution to mechanistic models. We present here a comprehensive overview of the most recently solved structures of ABC exporters, focusing on new insights regarding the nature of substrate polyspecificity and the physiological relevance of the 'open-apo' conformation. This review evaluates the claim that the latter may be an artefact of detergent solubilisation, and we hypothesise that the biophysical properties of the membrane play a key role in the function of ABC exporters allowing them to behave like a 'spring-hinge' during their transport cycle

Charcoal evidence that rising atmospheric oxygen terminated Early Jurassic ocean anoxia

This is the final version of the article. Available from Springer Nature via the DOI in this record.The Toarcian Oceanic Anoxic Event (T-OAE) was characterized by a major disturbance to the global carbon(C)-cycle, and depleted oxygen in Earth’s oceans resulting in marine mass extinction. Numerical models predict that increased organic carbon burial should drive a rise in atmospheric oxygen (pO2) leading to termination of an OAE after ∼1 Myr. Wildfire is highly responsive to changes in pO2 implying that fire-activity should vary across OAEs. Here we test this hypothesis by tracing variations in the abundance of fossil charcoal across the T-OAE. We report a sustained ∼800 kyr enhancement of fire-activity beginning ∼1 Myr after the onset of the T-OAE and peaking during its termination. This major enhancement of fire occurred across the timescale of predicted pO2 variations, and we argue this was primarily driven by increased pO2. Our study provides the first fossil-based evidence suggesting that fire-feedbacks to rising pO2 may have aided in terminating the T-OAE.We thank the Natural Environment Research Council for funding through a studentship grant NE/L501669/1 to S.J.B. C.M.B. acknowledges funding via an ERC Starter Grant ERC-2013-StG-335891-ECOFLAM. S.P.H., T.M.L. and C.M.B. acknowledge funding from the NERC ‘JET’ grant NE/N018508/1, as well as a Royal Society Wolfson Research Merit Award supporting T.M.L

The REPAIRER Reporting System for Integrating Human Factors into SMS in Aviation Maintenance

Acknowledging the FAA’s well-known PEAR model, and the influence of the dirty dozen in aviation maintenance, the authors examine a tracking and reporting system that fulfills FAA requirements for safety management systems in aviation maintenance organizations. Implications and suggestions for a robust safety management system which encompasses human factors and ORM, applicable to an aviation maintenance environment are presented, with the inclusion of specific risk hazards. The resulting safety reporting system proposed addresses both consistency and reliability challenges, unique to the aviation maintenance environment. Using the four pillars of safety as a foundation, the REPAIRER strategy procedures serves as the safety policy pillar, through the examination and rating of potential risk hazards, based on the dirty dozen. The resulting reporting system leverages aviation maintenancespecific factors to identify and correct for human errors, improving the reliability of maintenance procedures, enhancing safety practices, and ultimately creating a greater state of operational readiness

Vibrio vulnificus Type 6 Secretion System 1 contains anti-Bacterial properties.

This is the final version of the article. Available from Public Library of Science via the DOI in this record.Vibrio vulnificus is a bacterium responsible for severe gastroenteritis, sepsis and wound infections. Gastroenteritis and sepsis are commonly associated with the consumption of raw oysters, whereas wound infection is often associated with the handling of contaminated fish. Although classical virulence factors of this emerging pathogen are well characterised, there remains a paucity of knowledge regarding the general biology of this species. To investigate the presence of previously unreported virulence factors, we applied whole genome sequencing to a panel of ten V. vulnificus strains with varying virulence potentials. This identified two novel type 6 secretion systems (T6SSs), systems that are known to have a role in bacterial virulence and population dynamics. By utilising a range of molecular techniques and assays we have demonstrated the functionality of one of these T6SSs. Furthermore, we have shown that this system is subject to thermoregulation and is negatively regulated by increasing salinity concentrations. This secretion system was also shown to be involved in the killing of V. vulnificus strains that did not possess this system and a model is proposed as to how this interaction may contribute to population dynamics within V. vulnificus strains. In addition to this intra-species killing, this system also contributes to the killing of inter bacterial species and may have a role in the general composition of Vibrio species in the environment.This work was funded by a CEFAS-Exeter University Alliance PhD Studentship awarded to SRC and SLM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

The Irie Classroom Toolbox, a universal violence-prevention teacher-training programme, in Jamaican preschools: a single-blind, cluster-randomised controlled trial

BACKGROUND: Violence is a leading global public health problem, and interventions in early childhood are important in the primary prevention of violence. We tested whether the Irie Classroom Toolbox, a violence-prevention teacher-training programme reduced violence against children by teachers and reduced class-wide child aggression in Jamaican preschools (catering to children aged 3-6 years). METHODS: We did a single-blind, cluster-randomised controlled trial in 76 preschools in Kingston and St Andrew, randomly selected, using simple randomisation, from 120 eligible preschools. Inclusion criteria were two to four classes of children; at least ten children per class; and located in an urban area. We randomly assigned preschools (1:1) to either the Irie Classroom Toolbox intervention or waiting-list control that received no intervention, using a computer-generated randomisation sequence by an independent statistician masked to school identity. The Toolbox involved training teachers in classroom behaviour management and promoting child social-emotional competence. All assessors were masked to group assignment. All teachers and classrooms in the selected schools participated in the study. Within each school, we used simple randomisation to randomly select up to 12 children aged 4 years for evaluation of child outcomes. The Toolbox intervention was implemented from August to April the following year. Teacher and classroom measures were done at baseline (the summer school term; ie, May to June), post-intervention (after 8 months of intervention; ie, May to June of the following year), and 1-year follow-up (ie, May to June 2 years later). The primary outcomes were observations of violence against children (including physical violence and psychological aggression) by teachers occurring across one full school day, and class-wide child aggression occurring over five 20-min intervals on another school day, all measured at post-intervention and 1-year follow-up and analysed by intention to treat. This trial is registered with ISRCTN, number ISRCTN11968472. FINDINGS: Between June 22, 2015, and April 29, 2016, (after baseline measurements were completed), we assigned 38 preschools (with 119 teachers) to the Toolbox intervention and 38 preschools (with 110 teachers) to control. 441 children in the intervention schools and 424 in the control schools were included in the evaluation. All schools were included in the post-intervention and follow-up analyses. There were fewer counts of violence against children by teachers in the intervention schools compared with control schools at post-intervention (median counts 3 [IQR 0-11] vs 15 [3-35]; effect size -67·12%, 95% CI -80·71 to -53·52, p<0·0001) and 1-year follow-up (median counts 3 [IQR 0-9] vs 6 [1-16]; effect size -53·86, 95% CI -71·08 to -36·65, p<0·0001). No differences between groups were found for class-wide child aggression at post-intervention (effect size 0·07, 95% CI -0·16 to 0·29, p=0·72) or 1-year follow-up (-0·14, -0·42 to 0·16, p=0·72). INTERPRETATION: In Jamaican preschools, the Irie Classroom Toolbox effectively reduced violence against children by teachers. The Toolbox was designed for use with undertrained teachers working in low-resource settings and should be effective with early childhood practitioners in other LMICs. Additional research is needed to further develop the Toolbox to reduce class-wide child aggression. FUNDING: Medical Research Council, Wellcome Trust, UK Aid, and the National Institute of Health Research

Fixing the Broken Phosphorus Cycle: Wastewater Remediation by Microalgal Polyphosphates

Phosphorus (P), in the form of phosphate derived from either inorganic (Pi) or organic (Po) forms is an essential macronutrient for all life. P undergoes a biogeochemical cycle within the environment, but anthropogenic redistribution through inefficient agricultural practice and inadequate nutrient recovery at wastewater treatment works have resulted in a sustained transfer of P from rock deposits to land and aquatic environments. Our present and near future supply of P is primarily mined from rock P reserves in a limited number of geographical regions. To help ensure that this resource is adequate for humanity’s food security, an energy-efficient means of recovering P from waste and recycling it for agriculture is required. This will also help to address excess discharge to water bodies and the resulting eutrophication. Microalgae possess the advantage of polymeric inorganic polyphosphate (PolyP) storage which can potentially operate simultaneously with remediation of waste nitrogen and phosphorus streams and flue gases (CO2, SOx, and NOx). Having high productivity in photoautotrophic, mixotrophic or heterotrophic growth modes, they can be harnessed in wastewater remediation strategies for biofuel production either directly (biodiesel) or in conjunction with anaerobic digestion (biogas) or dark fermentation (biohydrogen). Regulation of algal P uptake, storage, and mobilization is intertwined with the cellular status of other macronutrients (e.g., nitrogen and sulphur) in addition to the manufacture of other storage products (e.g., carbohydrate and lipids) or macromolecules (e.g., cell wall). A greater understanding of controlling factors in this complex interaction is required to facilitate and improve P control, recovery, and reuse from waste streams. The best understood algal genetic model is Chlamydomonas reinhardtii in terms of utility and shared resources. It also displays mixotrophic growth and advantageously, species of this genus are often found growing in wastewater treatment plants. In this review, we focus primarily on the molecular and genetic aspects of PolyP production or turnover and place this knowledge in the context of wastewater remediation and highlight developments and challenges in this field

Computational study of the enhancement of graphene electrodes for use in Li-ion batteries via forming superlattices with transition metal dichalcogenides

This is the final version. Available on open access from the American Chemical Society via the DOI in this record. In our study, we examined nine transition metal dichalcogenide (TMDC)-graphene superlattices as potential Li-ion intercalation electrodes. We determined their voltages, with ScS2-graphene in T- and R-phases showing the highest at around 3 V, while the others ranged from 0 to 1.5 V. Most superlattices exhibited minimal volumetric expansion (5 to 10%), similar to NMC (8%), except for SnS2-T and NiS2-T, which expanded up to nearly 20%. We evaluated their capacities using a stability metric, EIS, and found that ScS2-T, ScS2-R, and TiS2-T could be intercalated up to two Li ions per MX2 unit without decomposing to Li2S, yielding capacities of 306.77 mA h/g for both ScS2 phases and 310.84 mA h/g for TiS2-T, roughly equivalent to LiC2. MoS2-T could accept Li up to a limit of a = 15/16 in LiaMoS2Cb, corresponding to a capacity of 121.29 mA h/g (equivalent to LiC4). Examining the influence of graphene layers on MoS2-T, we observed a voltage decrease and an initial EIS decrease before effectively flat lining, which is due to charge donation to the middle graphene layer, reducing the electron concentration near the TMDC layer. As graphene layers increased, overall volume expansion decreased with Li intercalation, which is attributed to the in-plane expansion changing. Our results underscore the potential of TMDC-graphene superlattices as Li-ion intercalation electrodes, offering low volumetric expansions, high capacities, and a wide voltage range. These superlattices all show an increase in the capacity of the graphene.Engineering and Physical Sciences Research Council (EPSRC

Properties of layered TMDC superlattices for electrodes in Li-ion and Mg-ion batteries

This is the final version. Available on open access from the American Chemical Society via the DOI in this record. In this work, we present a first-principles investigation of the properties of superlattices made from transition metal dichalcogenides for use as electrodes in lithium-ion and magnesium-ion batteries. From a study of 50 pairings, we show that, in general, the volumetric expansion, intercalation voltages, and thermodynamic stability of vdW superlattice structures can be well approximated with the average value of the equivalent property for the component layers. We also found that the band gap can be reduced, improving the conductivity. Thus, we conclude that superlattice construction can be used to improve material properties through the tuning of intercalation voltages toward specific values and by increasing the stability of conversion-susceptible materials. For example, we demonstrate how pairing SnS2 with systems such as MoS2 can change it from a conversion to an intercalation material, thus opening it up for use in intercalation electrodes.Engineering and Physical Sciences Research Council (EPSRC

Water incident related hospital activity across England between 1997/8 and 2003/4: a retrospective descriptive study

Every year in the United Kingdom, 10,000 people will die from accidental injury and the treatment of these injuries will cost the NHS £2 billion and the consequences of injuries received at home cost society a further £25 billion [1]. Non-fatal injuries result in 720,000 people being admitted to hospital a year and more than six million visits to accident and emergency departments each year [2]. Drowning is the second leading cause of unintentional injury mortality globally behind road traffic injuries. It is estimated that a total of 409, 272 people drown each year [3]. This equates to a global incident rate of 7.4 deaths per 100, 000 people worldwide and relates to a further 1.3 million Disability Adjusted Life Years (DALYs) which are lost as a result of premature death or disability [4]. 'Death' represents only the tip of the injury "iceberg" [5]. For every life lost from an injury, many more people are admitted to hospital, attend accident and emergency departments or general practitioners, are rescued by search and rescue organisations or resolve the situation themselves. It is estimated that 1.3 million people are injured as a result of near drowning episodes globally and that many more hundreds of thousands of people are affected through incidents and near misses but there are no accurate data [4]. The United Kingdom has reported a variable drowning fatality rate, the injury chart book reports a rate of 1.0 – 1.5 per 100,000 [6] and other studies suggest a rate as low as 0.5 per 100, 000 population [7] for accidental drowning and submersion, based on the International Classification of Disease 10 code W65 – 74, however, the problem is even greater and these Global Burden of Disease (GDB) figures are an underestimate of all drowning deaths, since they exclude drownings due to cataclysms (floods), water related transport accidents, assaults and suicide [3]. A recent study in Scotland highlighted this underestimation in drowning fatality data and found that the overall death rate due to drownings in Scotland 3.26 per 100,000 [8]. Even though drowning fatality rates in the United Kingdom vary, little is known about the people who are admitted to hospital after an incident either in or on water. This paper seeks to address this gap in our knowledge through the investigation of the data available on those admitted to NHS hospitals in England