• The sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPase (SERCA) is the likely molecular target for the acute toxicity of the brominated flame retardant hexabromocyclododecane (HBCD).

      Al-Mousa, Fawaz; Michelangeli, Francesco; University of Birmingham, UK (Elsevier, 2014-01-01)
      Hexabromocyclododecane (HBCD) is a widely utilised brominated flame retardant (BFR). It has been shown to bio-accumulate within organisms, including man, and possibly cause neurological disorders. The acute neurotoxicity of HBCD, and six other unrelated BFRs, were assessed in SH-SY5Y human neuroblastoma cells by 24h viability assays and HBCD proved to be the most lethal (LC50, 3μM). In addition, the effects of these BFRs were also assessed for their potency at inhibiting the sarcoplasmic-endoplasmic reticulum Ca(2+) ATPase (SERCA) derived from the SH-SY5Y cells and again HBCD was the most potent (IC50, 2.7μM). The data for the other BFRs tested showed a direct correlation (coefficient 0.94) between the potencies of inducing cell death and inhibiting the Ca(2+) ATPase, indicating that SERCA is likely to be the molecular target for acute toxicity. Mechanistic studies of HBCD on the Ca(2+) ATPase suggest that it affects ATP binding, phosphorylation as well as the E2 to E1 transition step.
    • Scenario-Led Habitat Modelling of Land Use Change Impacts on Key Species

      Geary, Matthew; Fielding, Alan H.; McGowan, Philip J. K.; Marsden, Stuart J.; University of Chester, Manchester Metropolitan University; Newcastle University (PLOS, 2015-11-16)
      Accurate predictions of the impacts of future land use change on species of conservation concern can help to inform policy-makers and improve conservation measures. If predictions are spatially explicit, predicted consequences of likely land use changes could be accessible to land managers at a scale relevant to their working landscape. We introduce a method, based on open source software, which integrates habitat suitability modelling with scenario-building, and illustrate its use by investigating the effects of alternative land use change scenarios on landscape suitability for black grouse Tetrao tetrix. Expert opinion was used to construct five near-future (twenty years) scenarios for the 800 km2 study site in upland Scotland. For each scenario, the cover of different land use types was altered by 5–30% from 20 random starting locations and changes in habitat suitability assessed by projecting a MaxEnt suitability model onto each simulated landscape. A scenario converting grazed land to moorland and open forestry was the most beneficial for black grouse, and ‘increased grazing’ (the opposite conversion) the most detrimental. Positioning of new landscape blocks was shown to be important in some situations. Increasing the area of open-canopy forestry caused a proportional decrease in suitability, but suitability gains for the ‘reduced grazing’ scenario were nonlinear. ‘Scenario-led’ landscape simulation models can be applied in assessments of the impacts of land use change both on individual species and also on diversity and community measures, or ecosystem services. A next step would be to include landscape configuration more explicitly in the simulation models, both to make them more realistic, and to examine the effects of habitat placement more thoroughly. In this example, the recommended policy would be incentives on grazing reduction to benefit black grouse.
    • Seasonality in birth rate in two 19th century North Wales parishes

      Lewis, Stephen J.; Glenn, Janine; Chester College of Higher Education (2000)
      An understanding of the basic patterns in the seasonality of birth rate may be useful in certain fertility techniques. The use of artificial birth control, however, has had the effect of masking the influence of underlying biometeriological factors. To elucidate trends in birth seasonality in the absence of current social factors, a study useing nineteenth-century parish records was undertaken. Analysis of 5,905 births recorded in the baptismal records of the parishes of Hawarden and Northop between the years 1837 and 1886 revealed significant seasonal trend with a peak occuring in the spring. Further analysis showed a significant positive correlation occuring between the (standardized) numbers of births in each month and the mean day length (hours between sunrise and sunset) of the pulative month of conception.
    • Seasonality of Plasmodium falciparum transmission: a systematic review

      Reiner, Robert C.; Geary, Matthew; Atkinson, Peter M.; Smith, David L.; Gething, Peter W.; 1 Fogarty International Center, National Institutes of Health, Bethesda, MD, USA 2 Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA 3 Department of Entomology, University of California, Davis, CA, USA 4 Department of Biological Sciences, University of Chester, Chester, UK 5 Faculty of Science and Technology, Engineering Building, Lancaster University, Lancaster LA1 4YR, UK 6 Faculty of Geosciences, University of Utrecht, Heidelberglaan 2, Utrecht, 3584 CS, The Netherlands 7 School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast, Belfast BT7 1NN, Northern Ireland, UK 8 Geography and Environment, University of Southampton, Highfield, Southampton SO17 1BJ, UK 9 Center for Disease Dynamics, Economics and Policy, Washington, DC, USA 10 Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, UK (BioMed Central, 2015-09-15)
      Background Although Plasmodium falciparum transmission frequently exhibits seasonal patterns, the drivers of malaria seasonality are often unclear. Given the massive variation in the landscape upon which transmission acts, intra-annual fluctuations are likely influenced by different factors in different settings. Further, the presence of potentially substantial inter-annual variation can mask seasonal patterns; it may be that a location has “strongly seasonal” transmission and yet no single season ever matches the mean, or synoptic, curve. Accurate accounting of seasonality can inform efficient malaria control and treatment strategies. In spite of the demonstrable importance of accurately capturing the seasonality of malaria, data required to describe these patterns is not universally accessible and as such localized and regional efforts at quantifying malaria seasonality are disjointed and not easily generalized. Methods The purpose of this review was to audit the literature on seasonality of P. falciparum and quantitatively summarize the collective findings. Six search terms were selected to systematically compile a list of papers relevant to the seasonality of P. falciparum transmission, and a questionnaire was developed to catalogue the manuscripts. Results and discussion 152 manuscripts were identified as relating to the seasonality of malaria transmission, deaths due to malaria or the population dynamics of mosquito vectors of malaria. Among these, there were 126 statistical analyses and 31 mechanistic analyses (some manuscripts did both). Discussion Identified relationships between temporal patterns in malaria and climatological drivers of malaria varied greatly across the globe, with different drivers appearing important in different locations. Although commonly studied drivers of malaria such as temperature and rainfall were often found to significantly influence transmission, the lags between a weather event and a resulting change in malaria transmission also varied greatly by location. Conclusions The contradicting results of studies using similar data and modelling approaches from similar locations as well as the confounding nature of climatological covariates underlines the importance of a multi-faceted modelling approach that attempts to capture seasonal patterns at both small and large spatial scales. Keywords: Plasmodium falciparum ; Seasonality; Climatic drivers
    • A simple procedure for investigating differences in sexual dimorphism between populations

      Lewis, Stephen J.; Chester College of Higher Education (Oxbow Books (for The Osteoarchaeological Research Group), 1997-12-01)
      Although sexual dimorphism has a strong genetic component in many animals, external factors may alter its expression - enhancing or diminishing it depending on the parameter measured and the type of influence experienced. A measure of sexual dimorphism may be used, therefore, to characterise a whole population and the factors acting upon it. Differences between populations for such factors may then be investigated by comparing sexual dimorphisms and may be more informative than merely comparing population means. A quick and relatively simple technique which provides a coefficient of the relationship between a continuous variable and another which is dichotomous, such as sex, is the point biserial correlation. This is a less frequently described extension of the commonly used Pearson product-moment correlation. The point-biserial correlation coefficients can be calculated for a given parameter and compared to determine whether the same sexual dimorphism is evident in different samples. If it is not, some factor influencing one or other population, as a whole, may require further investigation. The full procedure, which can be performed without the need for statistical tables, and the necessary formulae are described. This method, in its generalised form, may also be applied to the study of bilateral asymmetry.
    • A simple procedure for testing for differences in sexual dimorphism between populations

      Lewis, Stephen J.; Chester College of Higher Education (InterStat, 2004)
      Using point bi-serial correlation, an approach to the biological problem of comparing differences in sexual dimorphism between populations is presented. In particular, a way of deriving the point bi-serial correlation coefficient from summary statistics (means, standard deviations and sample sizes) is given. This bypasses the need for access to raw data.
    • Skeletal changes during catch-up growth - suggestions from a rat model

      Lewis, Stephen J.; Chester College of Higher Education (2001)
      The removal of a growth limiting influence, such as undernutrition, is frequently followed by a period of growth at a rate greater than normally expected for chronological age. This, so called 'catch-up growth', tends to return affected individuals to their original growth trajectory. How catch-up growth is controlled or regulated remains unclear. Histological studies of the proximal tibial growth plate in rats which had been undernourished by half-feeding between the 56th and 70th days (post partum) showed them to be thinner than those of controls. Upon inspection, the chondrocytes also appeared to be flatter in profile and less numerous. However, during the catch-up period, when food was again allowed ad libitum, previously undernourished rats showed wider growth plates with rounder and more numerous chondrocytes than controls. It was noted that such changes were similar to those that accompany sectioning of the periosteum and the release of growth restraint that results. A study of the flexibility of the sacro-iliac joint in the same animals suggested that it was less flexible following undernutrition but more so during the catch-up period, by comparison with controls. This was in contrast to a progressive loss of flexibility shown by controls during the same period and would appear to result from changes in the characteristics of the fibrous connective tissues associated with the joint. If this reflects a more generalized change in such connective tissues, but particularly the periosteum, ligaments and joint capsules, this may represent a means whereby skeletal growth rate during the catch-up period may be influenced in a co-ordinated manner.
    • Social stability in semiferal ponies: networks show interannual stability alongside seasonal flexibility

      Stanley, Christina R.; Mettke-Hofmann, Claudia; Hager, Reinmar; Shultz, Susanne; University of Chester; University of Manchester; Liverpool John Moores University (Elsevier, 2017-06-23)
      Long-term relationships that underlie many stable mammalian groups often occur between philopatric kin. Although stable groups of nonrelatives appear to be less common, there is increasing evidence that social bonds between nonkin may confer sufficient intrinsic fitness benefits for these groups to persist. Here we evaluate whether social stability occurs in a bisexually dispersing species where social bonds have been shown to have reproductive benefits: the feral horse, Equus caballus. First, we quantified female social stability by applying a three-level framework to a 3-year data set of associations in semiferal ponies; this tested for stability at the individual, dyadic and subpopulation levels. Despite the relative weakness of these female bonds, we found significant social stability across all levels, as shown by stable association preferences, social networks and individual network positions. Second, we investigated how seasonality impacts on social bond strength and grouping patterns. We found seasonal fluctuations in female gregariousness, with a peak during the mating season. We therefore propose that significant social stability in female horses is coupled with a degree of flexibility that allows for effects of ecological fluctuations. Although social network analysis is widely used in behavioural ecological research, this is one of only a handful of studies to assess the temporal dynamics of networks over a significant timescale. Temporal stability in female relationships suggests that equid social structures are multifaceted: although bonds between stallions and mares are clearly strong, long-term relationships between mares underpin the social network structure. We suggest this framework could be used to assess social stability in other group-living species in order to improve our understanding of the nature of social bonds.
    • Solving the conundrum of health and disease

      Lewis, Stephen J.; Chester College of Higher Education (1997)
    • Some notes on crucifixion

      Lewis, Stephen J.; Chester College of Higher Education (1995)
      This article discusses the injuries caused by crucifixion, based on an adult male skeleton found in ossuary I:4 in north-east Jerusalem in 1968.
    • Some research possibilities in diagnostic radiography

      Lewis, Stephen J.; University College Chester (Elsevier, 1998)
      Although scientific method is usually viewed as starting with hypotheses which must then be exposed to experimental test, there are situations where this rigid scenario is inappropriate. Fortunately, the alternatives provide avenues for valuable investigative work in radiographic research. Research questions may be addressed by collecting data from existing sources in a way that not only provides fundamental information about human biology, but may improve the efficacy of radiographic practice while avoiding ethical problems about the use of patients. Among those involved in osteology, it is radiographers who see and store the most bone images. Subsequently, they have access to more osteological information than anyone else. All that remains is for this information to be extracted and put into a more accessible form. Since they are closely involved with the patients from whom their radiographs stem, there are research questions which radiographers are uniquely situated to raise.
    • Some summary data from the N.W. Wales hand osteological database

      Lewis, Stephen J.; Chester College of Higher Education (Oxbow Books (for the Osteoarchaeological Research Group), 1999-12-01)
      Probably the richest store of osteological information lies in the radiographic images stored in X-ray departments. These have been greatly under-used. As an example of the sort of data available, some summary statistics from the N.W. Wales Hand Osteological Database are given. This data may be compared with historic or extant populations. Further data is available to colleagues on request.
    • Spatial and temporal changes in the distribution of salt marsh vegetation communities in the Dee estuary, NW England, determinded from aerial photographs

      Huckle, Jonathan M.; Potter, Jacqueline; Marrs, Robert H.; University College Chester (Potter) (Springer, 2004)
    • Spatial variation in species composition of Saprolegnia, a parasitic oomycete of amphibian eggs, in Scotland

      Muir, Anna P.; Kilbride, Elizabeth; Mable, Barbara K.; University of Chester; University of Glasgow (The British Herpetological Society, 2015-10-01)
      Parasitic water moulds in the genus Saprolegnia cause mortality of amphibian embryos and reduced size at metamorphosis, leading to increased adult mortality. Most studies of virulence have focused on only a single Saprolegnia species, but the Saprolegnia species associated with amphibian eggs and their distributions are not well known. This study aimed to investigate the distribution of amphibian-associated water moulds in Scotland. In particular, we asked the questions: i) Does Saprolegnia species composition vary between sites?; and ii) Is presence of Saprolegnia related to environmental parameters? Common frog (Rana temporaria) eggs with evidence of Saprolegnia infection were sampled from ten sites, cultured, and the 28S region of the rDNA array sequenced. Thirteen samples isolated from four sites were identified as members of the Saprolegniaceae and the ITS region of these samples were subsequently sequenced to further resolve species identification. Four species of Saprolegnia were found in total, with one or two species of Saprolegnia present in each of four sites. S. diclina was the most common species identified and was found at three of the four sites. Acidity was significantly lower and altitude significantly higher at sites where Saprolegniaceae were present. Therefore, R. temporaria eggs in different pools are subject to infection by different, and in some instances more than one, species of Saprolegnia. Overall, our findings suggest that future studies of virulence need to consider the effect of multiple Saprolegnia species within a site as well as the population of origin of the amphibian host
    • Statins increase osteoprotegerin production and apoptosis in osteoblastic cells

      Smith, Heather L.; Buck, I.; Williams, John H. H.; Marshall, Michael J. (American Society for Bone and Mineral Research, 2005)
    • Stereoselective uptake of cell-penetrating peptides is conserved in antisense oligonucleotide polyplexes

      Favretto, Marco E.; Brock, Roland; Radboud University Medical Center (Wiley-VCH Verlag, 2014-11-10)
      Stereochemistry matters. A significant conceptual advancement is presented toward the understanding of how functional characteristics of delivery peptides can translate into functional characteristics of peptide-based oligoplexes
    • Stimulating public interest in our urban environment in Wales / Ennyn diddirdeb y cyhoedd yn ein hamgylchedd trefol yng Nghymru

      Burek, Cynthia V.; University College Chester (Cadw, 2005-01-01)
      This book chapter discusses urban geology trails in Wales and how they can act as an inexpensive method of increasing public awareness of local geology.
    • Stimulating public interest in our urban geology in Wales

      Burek, Cynthia V.; University of Chester (National Museums and Galleries of Wales, 2009-05-11)
    • Survey of reproduction and calf rearing in Asian and African elephants in European zoos

      Hartley, Matt; Stanley, Christina R.; University of Chester (European Association of Zoos and Aquaria, 2016-07-31)
      Acyclicity, conception failure, abortion, stillbirth, dystocia, infanticide and neonatal mortality have all been reported as causes of reproductive failure in zoo elephants. These events are often reported as single case reports or in specific studies focused on a particular stage in the reproductive process. In North America wider surveys of reproduction in the zoo elephant population have been completed and repeated to provide data over a number of years. This study is the largest and most comprehensive study of reproduction in the European zoo elephant population to date. Two questionnaires collected data from throughout the reproductive process from assessing cyclicity to independence of the calf at 5 years old. Information was collected regarding 189 birth events. Many causative and contributing factors such as obesity, infectious disease, husbandry, facilities, stress, behaviour, herd size and social grouping have been proposed. The importance of these was assessed and where possible association identified using statistical analysis. In African elephants, this study found that age, obesity, reproductive pathology and dominance, identified as important risk factors for failure to conceive in the American zoo elephant population were of low importance. The most significant cause in Europe was lack of access to a compatible bull. In Asian elephants reproductive failure was much less common but when it did occur age and reproductive pathologies were significant factors as found in previous studies. Previous studies have found that age, obesity and infanticide were considered as the most important risk factors in the period from birth to rearing. In this survey it was found that herd stability and compatibility, allomothering or maternal experience and management at parturition can significantly influence reproductive success. Elephant Endotheliotropic Herpes virus was confirmed as the biggest cause of calf mortality. This work provides evidence to support changes to elephant management in European zoos in order to encourage development of social and affiliative herd behaviours and improve reproductive success.
    • A Systems Biology Approach Reveals a Calcium-Dependent Mechanism for Basal Toxicity in Daphnia magna.

      Antczak, Philip; White, Thomas A.; Giri, Anirudha; Michelangeli, Francesco; Viant, Mark R.; Cronin, Mark T. D.; Vulpe, Chris; Falciani, Francesco; University of Birmingham, University of Liverpool, University of California, Berkley, Liverpool John Moores, Assam University (ACS publications, 2015-09-01)
      The expanding diversity and ever increasing amounts of man-made chemicals discharged to the environment pose largely unknown hazards to ecosystem and human health. The concept of adverse outcome pathways (AOPs) emerged as a comprehensive framework for risk assessment. However, the limited mechanistic information available for most chemicals and a lack of biological pathway annotation in many species represent significant challenges to effective implementation of this approach. Here, a systems level, multistep modeling strategy demonstrates how to integrate information on chemical structure with mechanistic insight from genomic studies, and phenotypic effects to define a putative adverse outcome pathway. Results indicated that transcriptional changes indicative of intracellular calcium mobilization were significantly overrepresented in Daphnia magna (DM) exposed to sublethal doses of presumed narcotic chemicals with log Kow ≥ 1.8. Treatment of DM with a calcium ATPase pump inhibitor substantially recapitulated the common transcriptional changes. We hypothesize that calcium mobilization is a potential key molecular initiating event in DM basal (narcosis) toxicity. Heart beat rate analysis and metabolome analysis indicated sublethal effects consistent with perturbations of calcium preceding overt acute toxicity. Together, the results indicate that altered calcium homeostasis may be a key early event in basal toxicity or narcosis induced by lipophilic compounds.