Regulation and Measurement of Nitrification in Terrestrial Systems

Nitric oxide (NO) is a relatively short-lived trace gas that reacts with oxygen in the troposphere to produce the air pollutant ozone. It also reacts with water vapor to form nitric and nitrous acids, which acidify precipitation and increase N deposition. Models currently used to predict soil NO fluxes are based on the assumption that NO flux is proportional to the gross rate of nitrification or N mineralization; however, this assumption has not been tested because of the difficulty in measuring gross N-cycling rates in situ. We measured soil NO fluxes, gross and net N-cycling rates, and a variety of other soil characteristics in the forest floor and intact soil cores at nine undisturbed forest and rangeland ecosystems of New Mexico, Utah, and Oregon, USA, to determine which soil variables were most closely related to soil NO flux. Soil NO fluxes ranged from a low of 0.02 ng N·m22·s21, prior to wetting in a western hemlock–sitka spruce forest on the Oregon coast, to a high of 6.74 ng N·m22·s21, one hour after soil wetting in a juniper woodland of central Oregon. In contrast to our expectations, neither gross nitrification nor gross mineralization was correlated with soil NO flux. Fluxes were positively correlated with net rates of mineralization and nitrification, soil NO3 2 concentrations, bulk density, and pH, and negatively correlated with gross rates of NO3 2 consumption in the forest floor, soil organic carbon (SOC), soil C:N, and soil water content. Principal-component analysis showed that NO flux after water addition (2 cm of water) had a strong negative correlation with microbial demand for N (as indicated by net mineralization, net nitrification, SOC, and C:N). Our results suggest that, even in well-drained soils, NO efflux is limited more by NO consumption than by NO production. As a result, models utilizing the more easily measured net rates, rather than gross rates, may be better predictors of soil NO fluxes across a range of ecosystems

Exercise-based cardiac rehabilitation improves exercise capacity and health-related quality of life in people with atrial fibrillation: a systematic review and meta-analysis of randomised and non-randomised trials

Objective: The aim of this study was to undertake a contemporary review of the impact of exercise-based cardiac rehabilitation (CR) targeted at patients with atrial fibrillation (AF). Methods: We conducted searches of PubMED, EMBASE and the Cochrane Library of Controlled Trials (up until 30 November 2017) using key terms related to exercise-based CR and AF. Randomised and non-randomised controlled trials were included if they compared the effects of an exercise-based CR intervention to a no exercise or usual care control group. Meta-analyses of outcomes were conducted where appropriate. Results: The nine randomised trials included 959 (483 exercise-based CR vs 476 controls) patients with various types of AF. Compared with control, pooled analysis showed no difference in all-cause mortality (risk ratio (RR) 1.08, 95% CI 0.77 to 1.53, p=0.64) following exercise-based CR. However, there were improvements in health-related quality of life (mean SF-36 mental component score (MCS): 4.00, 95% CI 0.26 to 7.74; p=0.04 and mean SF-36 physical component score: 1.82, 95% CI 0.06 to 3.59; p=0.04) and exercise capacity (mean peak VO2: 1.59 ml/kg/min, 95% CI 0.11 to 3.08; p=0.04; mean 6 min walk test: 46.9 m, 95% CI 26.4 to 67.4; p<0.001) with exercise-based CR. Improvements were also seen in AF symptom burden and markers of cardiac function. Conclusions: Exercise capacity, cardiac function, symptom burden and health-related quality of life were improved with exercise-based CR in the short term (up to 6 months) targeted at patients with AF. However, high-quality multicentre randomised trials are needed to clarify the impact of exercise-based CR on key patient and health system outcomes (including health-related quality of life, mortality, hospitalisation and costs) and how these effects may vary across AF subtypes

Live-Cell Imaging of Cellular Proteins by a Strain-Promoted Azide–Alkyne Cycloaddition

Live and let dye: Three coumarin-cyclooctyne conjugates have been used to label proteins tagged with azidohomoalanine in Rat-1 fibroblasts. All three fluorophores labeled intracellular proteins with fluorescence enhancements ranging from eight- to 20-fold. These conjugates are powerful tools for visualizing biomolecule dynamics in living cells

Structurally diverse hamigerans from the New Zealand marine sponge Hamigera tarangaensis: NMR-directed isolation, structure elucidation and antifungal activity

The NMR-directed investigation of the New Zealand marine sponge Hamigera tarangaensis has afforded ten new compounds of the hamigeran family, and a new 13-epi-verrucosane congener. Notably, hamigeran F (6) possesses an unusual carbon–carbon bond between C-12 and C-13, creating an unprecedented skeleton within this class. In particular, the structural features of 6, hamigeran H (10) and hamigeran J (12) imply a diterpenoid origin, which has allowed the putative biogenesis of three hamigeran carbon skeletons to be proposed based on geranyl geranyl pyrophosphate. All new hamigerans exhibited micromolar activity towards the HL-60 promyelocytic leukaemic cell line, and hamigeran G also selectively displayed antifungal activity in the budding yeast Saccharomyces cerevisiae. Homozygous deletion profiling (HOP) analysis suggests Golgi apparatus function as a potential target of this unusual class of sponge-derived terpenoids

The meaning of life in a developing universe

The evolution of life on Earth has produced an organism that is beginning to model and understand its own evolution and the possible future evolution of life in the universe. These models and associated evidence show that evolution on Earth has a trajectory. The scale over which living processes are organized cooperatively has increased progressively, as has its evolvability. Recent theoretical advances raise the possibility that this trajectory is itself part of a wider developmental process. According to these theories, the developmental process has been shaped by a larger evolutionary process that involves the reproduction of universes. This evolutionary process has tuned the key parameters of the universe to increase the likelihood that life will emerge and develop to produce outcomes that are successful in the larger process (e.g. a key outcome may be to produce life and intelligence that intentionally reproduces the universe and tunes the parameters of ‘offspring’ universes). Theory suggests that when life emerges on a planet, it moves along this trajectory of its own accord. However, at a particular point evolution will continue to advance only if organisms emerge that decide to advance the evolutionary process intentionally. The organisms must be prepared to make this commitment even though the ultimate nature and destination of the process is uncertain, and may forever remain unknown. Organisms that complete this transition to intentional evolution will drive the further development of life and intelligence in the universe. Humanity’s increasing understanding of the evolution of life in the universe is rapidly bringing it to the threshold of this major evolutionary transition

The first crop plant genetically engineered to release an insect pheromone for defence

Insect pheromones offer potential for managing pests of crop plants. Volatility and instability are problems for deployment in agriculture but could be solved by expressing genes for the biosynthesis of pheromones in the crop plants. This has now been achieved by genetically engineering a hexaploid variety of wheat to release (E)-β-farnesene (Eβf), the alarm pheromone for many pest aphids, using a synthetic gene based on a sequence from peppermint with a plastid targeting amino acid sequence, with or without a gene for biosynthesis of the precursor farnesyl diphosphate. Pure Eβf was produced in stably transformed wheat lines with no other detectable phenotype but requiring targeting of the gene produced to the plastid. In laboratory behavioural assays, three species of cereal aphids were repelled and foraging was increased for a parasitic natural enemy. Although these studies show considerable potential for aphid control, field trials employing the single and double constructs showed no reduction in aphids or increase in parasitism. Insect numbers were low and climatic conditions erratic suggesting the need for further trials or a closer imitation, in the plant, of alarm pheromone release

Scanning electrochemical microscopy for the interrogation of biologically modified surfaces

This thesis describes two novel applications of scanning electrochemical microscopy (SECM) to biological systems. The first involves the characterisation of a novel, impedance based genomic DNA biosensor - previously developed within the group. SECM in feedback mode was used to interrogate a DNA-polyelectrolyte film to determine whether the changes observed by impedance were detectable by SECM. Using the SECM micropositioning device to pattern a carbon ink substrate, a dotted array of polyethylenimine (PEI) and single stranded DNA (ssDNA) was fabricated. Using hexamine ruthenium chloride as the redox couple, the array was then interrogated by a SECM area scan before and following exposure to complementary and non-complementary DNA. Upon the exposure of the DNA/PEI array to complementary DNA, the feedback current over the functionalised region was observed to increase, whereas on exposure of the array to non-complementary DNA, an increase in feedback current was also observed - but to a lesser degree. The second SECM application described involves the use of SECM to detect protein expression in cells. Using an established immunochemical protocol, the transmembrane protein, CD44, expressed by cultured RT112 cells was labelled via a primary/secondary antibody complex to horseradish peroxidase. Using hydrogen peroxide and hydroquinone, the activity of the HRP label was subsequently detected by SECM in feedback mode. The microelectrode tip was biased at a potential of -0.4V, a potential sufficient for the reduction of benzoquinone - the redox active product of the HRP catalysed reaction. The work presented represents the first application of SECM to detecting protein expression in cells and effectively demonstrates the promise this technique holds for immunochemical applications. An analysis of Uniscan’s innovation network is also presented, which provides a valuable insight into the management of such resources and how they may be orchestrated to extract maximal innovative value for all parties involved in a collaborative relationship.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Financial incentives for large-scale wetland restoration: beyond markets to common asset trusts

Wetlands provide $47.4 trillion/year worth of ecosystem services globally and support immense biodiversity, yet face widespread drainage and pollution, and large-scale wetlands restoration is urgently needed. Payment for ecosystem service (PES) schemes provide a viable avenue for funding large-scale wetland restoration. However, schemes around the globe differ substantially in their goals, structure, challenges, and effectiveness in supporting large-scale wetland restoration. Here, we suggest wetland-based PES schemes use common asset trusts (CATs) to build investment portfolios of wetlands across landscapes that sustain and enhance overall provision of multiple ecosystem services. CATs can meet the needs of multiple investors, permit bundled payments, and provide flexibility to invest in the restoration of numerous services/values, all using a coordinated, highly collaborative, prioritized, and transparent process. CATs would support financial viability, facilitate efficiency to reduce administrative burdens, and enable credibility and social licence building to restore wetland values and services globally

NAA is a Marker of Disability in Secondary-Progressive MS: A Proton MR Spectroscopic Imaging Study

BACKGROUND AND PURPOSE: The secondary progressive phase of multiple sclerosis is characterised by disability progression due to processes that lead to neurodegeneration. Surrogate markers such as those derived from MRI are beneficial in understanding the pathophysiology that drives disease progression and its relationship to clinical disability. We undertook a 1H-MRS imaging study in a large secondary progressive MS (SPMS) cohort, to examine whether metabolic markers of brain injury are associated with measures of disability, both physical and cognitive. MATERIALS AND METHODS: A cross-sectional analysis of individuals with secondary-progressive MS was performed in 119 participants. They underwent 1H-MR spectroscopy to obtain estimated concentrations and ratios to total Cr for total NAA, mIns, Glx, and total Cho in normal-appearing WM and GM. Clinical outcome measures chosen were the following: Paced Auditory Serial Addition Test, Symbol Digit Modalities Test, Nine-Hole Peg Test, Timed 25-foot Walk Test, and the Expanded Disability Status Scale. The relationship between these neurometabolites and clinical disability measures was initially examined using Spearman rank correlations. Significant associations were then further analyzed in multiple regression models adjusting for age, sex, disease duration, T2 lesion load, normalized brain volume, and occurrence of relapses in 2 years preceding study entry. RESULTS: Significant associations, which were then confirmed by multiple linear regression, were found in normal-appearing WM for total NAA (tNAA)/total Cr (tCr) and the Nine-Hole Peg Test (ρ = 0.23; 95% CI, 0.06-0.40); tNAA and tNAA/tCr and the Paced Auditory Serial Addition Test (ρ = 0.21; 95% CI, 0.03-0.38) (ρ = 0.19; 95% CI, 0.01-0.36); mIns/tCr and the Paced Auditory Serial Addition Test, (ρ = -0.23; 95% CI, -0.39 to -0.05); and in GM for tCho and the Paced Auditory Serial Addition Test (ρ = -0.24; 95% CI, -0.40 to -0.06). No other GM or normal-appearing WM relationships were found with any metabolite, with associations found during initial correlation testing losing significance after multiple linear regression analysis. CONCLUSIONS: This study suggests that metabolic markers of neuroaxonal integrity and astrogliosis in normal-appearing WM and membrane turnover in GM may act as markers of disability in secondary-progressive MS

Development and validation of a recommended checklist for assessment of surgical videos quality: the LAParoscopic surgery Video Educational GuidelineS (LAP-VEGaS) video assessment tool

Introduction There has been a constant increase in the number of published surgical videos with preference for open-access sources, but the proportion of videos undergoing peer-review prior to publication has markedly decreased, raising questions over quality of the educational content presented. The aim of this study was the development and validation of a standard framework for the appraisal of surgical videos submitted for presentation and publication, the LAParoscopic surgery Video Educational GuidelineS (LAP-VEGaS) video assessment tool. Methods An international committee identified items for inclusion in the LAP-VEGaS video assessment tool and finalised the marking score utilising Delphi methodology. The tool was finally validated by anonymous evaluation of selected videos by a group of validators not involved in the tool development. Results 9 items were included in the LAP-VEGaS video assessment tool, with every item scoring from 0 (item not presented in the video) to 2 (item extensively presented in the video), with a total marking score ranging from 0 to 18. The LAP-VEGaS video assessment tool resulted highly accurate in identifying and selecting videos for acceptance for conference presentation and publication, with high level of internal consistency and generalisability. Conclusions We propose that peer review in adherence to the LAP-VEGaS video assessment tool could enhance the overall quality of published video outputs.[GRAPHICS]