Understanding community diversity on coastal defences : the role of key drivers and ecological enhancements

Coastal defences have become prevalent in the marine environment in response to rising sea levels and increasingly frequent coastal storms. However, due to insufficient habitat heterogeneity and physical complexity such structures support lower biodiversity than natural rocky shores. As a result, a range of ecological enhancements have been developed to address the diversity deficit. This thesis monitored colonization of an ecologically enhanced rock armour defence at Runswick Bay, North Yorkshire. Artificial rock pools and sandstone boulder habitats were incorporated into the defence design to increase habitat heterogeneity and groove microhabitats were engineered to increase small-scale complexity of granite boulders. Fourteen months after construction, diversity of sessile and mobile assemblages was significantly higher in artificial pool and sandstone boulder habitats than in unmodified granite boulder habitats. The community which developed on engineered grooves was not different to that of substrates without grooves. This thesis also examined whether fine-scale complexity (rugosity) and substrate orientation act as drivers of diversity on coastal defences. At both mid and upper shore height, the most rugose substrate had the highest diversity of sessile and mobile species. Over a regional scale, the age of defence was more important in determining community structure than rugosity. In addition, diversity and structure of communities differed significantly between North, North-east and East orientations at mid and upper shore height. This thesis demonstrates that increasing the habitat heterogeneity and incorporating natural substrata into rock armour defences can improve biodiversity. This thesis also demonstrates the importance of fine-scale complexity across tidal heights, and that environmental factors determined by orientation affect community structure. These results can be used to inform how ecological enhancements are applied in future developments

The coproporphyrin ferrochelatase of Staphylococcus aureus: mechanistic insights into a regulatory iron binding site

The majority of characterised ferrochelatase enzymes catalyse the final step of classical haem synthesis, inserting ferrous iron into protoporphyrin IX. However, for the recently-discovered coproporphyrin-dependent pathway, ferrochelatase catalyses the penultimate reaction where ferrous iron is inserted into coproporphyrin III. Ferrochelatase enzymes from the bacterial phyla Firmicutes and Actinobacteria have previously been shown to insert iron into coproporphyrin, and those from Bacillus subtilis and Staphylococcus aureus are known to be inhibited by elevated iron concentrations. The work herein reports a Km (coproporphyrin III) for S. aureus ferrochelatase of 1.5 µM and it is shown that elevating the iron concentration increases the Km for coproporphyrin III, providing a potential explanation for the observed iron-mediated substrate inhibition. Together, structural modelling, site-directed mutagenesis, and kinetic analyses confirm residue Glu271 as being essential for the binding of iron to the inhibitory regulatory site on S. aureus ferrochelatase, providing a molecular explanation for the observed substrate inhibition patterns. This work therefore has implications for how haem biosynthesis in S. aureus is regulated by iron availability

All-Sky Near Infrared Space Astrometry

Gaia is currently revolutionizing modern astronomy. However, much of the Galactic plane, center and the spiral arm regions are obscured by interstellar extinction, rendering them inaccessible because Gaia is an optical instrument. An all-sky near infrared (NIR) space observatory operating in the optical NIR, separated in time from the original Gaia would provide microarcsecond NIR astrometry and millimag photometry to penetrate obscured regions unraveling the internal dynamics of the Galaxy.Comment: 7 page

Depression and anxiety during the year before death from cancer.

OBJECTIVE: Previous studies of depression and anxiety during the year before death have reported different findings. We therefore aimed to study depression and anxiety in patients who had died from cancer and had previously attended cancer clinics. METHODS: We analysed routine data on 4869 deceased patients who had completed the Hospital Anxiety and Depression Scale (HADS) as part of their routine cancer care. The HADS data were linked with demographic, cancer and mortality data from national registries. We used data from all HADS completed in the last year of life to investigate the relationships between mean depression (HADS-D) and anxiety (HADS-A) scores and the percentages of high scores (≥11 on each subscale) and time to death (Analysis 1). This analysis used multivariable linear regression with cubic splines and robust standard errors to allow for multiple HADS from the same patients. We also investigated within-patient changes in scores (Analysis 2) in a subset of patients who had completed more than one HADS. RESULTS: In Analysis 1, modelled mean HADS-D scores increased by around 2.5 and the percentage of high HADS-D scores increased from 13% at six months before death to 30% at one month before death. Changes in HADS-A were smaller and occurred later. In Analysis 2, similar patterns were observed in individual patients' HADS scores. CONCLUSION: Depression should be looked for and treated in patients with cancer and a prognosis of six months or less, in order to maximise the quality of patients' remaining life

The HemQ coprohaem decarboxylase generates reactive oxygen species: implications for the evolution of classical haem biosynthesis

Bacteria require a haem biosynthetic pathway for the assembly of a variety of protein complexes including cytochromes, peroxidases, globins, and catalase. Haem is synthesised via a series of tetrapyrrole intermediates including non-metallated porphyrins such as protoporphyrin IX, which is well-known to generate reactive oxygen species (ROS) in the presence of light and oxygen. Staphylococcus aureus has an ancient haem biosynthetic pathway that proceeds via the formation of coproporphyrin III, a less reactive porphyrin. Herein, we demonstrate for the first time that HemY of S. aureus is able to generate both protoporphyrin IX and coproporphyrin III, and that the terminal enzyme of this pathway, HemQ, can stimulate the generation of protoporphyrin IX (but not coproporphyrin III). Assays with hydrogen peroxide, horseradish peroxidase, superoxide dismutase, and catalase confirm that this stimulatory effect is mediated by superoxide. Structural modelling reveals that HemQ enzymes do not possess the structural attributes that are common to peroxidases that form compound I [FeIV=O]+, which taken together with the superoxide data leaves Fenton chemistry as a likely route for the superoxide-mediated stimulation of protoporphyrinogen IX oxidase activity of HemY. This generation of toxic free radicals could explain why HemQ enzymes have not been identified in organisms that synthesise haem via the classical protoporphyrin IX pathway. This work has implications for the divergent evolution of haem biosynthesis in ancestral microorganisms and provides new structural and mechanistic insights into a recently discovered oxidative decarboxylase reaction

The associations between sedentary behaviour and mental health among adolescents:A systematic review

Background: With technological developments and modernised sedentary lifestyles has come an increase in diseases associated with inactivity such as obesity and other non-communicable diseases. Emerging evidence suggests that time spent sedentary may also interact with mental health. This systematic review examined the associations between sedentary behaviour and mental health problems among adolescents. Methods: This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, and applied a quality assessment tool for quantitative studies to identity best available evidence. Following stringent search strategy of the databases; Cumulative Index to Nursing and Allied Health Literature, Global Health, Health Source: Nursing and Academic Edition, MEDLINE, PsychARTICLES and PsycINFO, we identified 32 articles eligible for review. Results: All studies reported leisure screen time among adolescents, and two thirds of identified studies examined depressive symptomatology. Other mental health measures were; anxiety symptoms, self-esteem, suicide ideation, loneliness, stress, and psychological distress. Strong consistent evidence was found for the relationship between both depressive symptomatology and psychological distress, and time spent using screens for leisure. Moderate evidence supported the relationship between low self-esteem and screen use. Poorer mental health status was found among adolescents using screen time more than 2-3 h per day, and gender differences exist. Essential information was missing for quality of evidence including heterogeneity in mental health and screen time-based measures, and self-report data collection methods. Conclusions: The findings are of particular significance given the global public health concern of lifestyle-attributed diseases and the possibility for novel approaches to mental health. Future research should examine the psychological impact of reducing time spent using screens for leisure among adolescents, whilst accounting for possible confounding factors such as physical activity and dietary behaviours. It is critical that the reciprocal relationship between lifestyle behaviours and mental health is represented in both the psychiatric and public health forum