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Alleviating the unwanted effects of oxidative stress on Aβ clearance: A review of related concepts and strategies for the development of computational modelling
Get PDFTreatment for Alzheimer’s disease (AD) can be more effective in the early stages. Although we do not completely understand the aetiology of the early stages of AD, potential pathological factors (amyloid beta [Aβ] and tau) and other co-factors have been identified as causes of AD, which may indicate some of the mechanism at work in the early stages of AD. Today, one of the primary techniques used to help delay or prevent AD in the early stages involves alleviating the unwanted effects of oxidative stress on Aβ clearance. 4 Hydroxynonenal (HNE), a product of lipid peroxidation caused by oxidative stress, plays a key role in the adduction of the degrading proteases. This HNE employs a mechanism which decreases catalytic activity. This process ultimately impairs Aβ clearance. The degradation of HNE-modified proteins helps to alleviate the unwanted effects of oxidative stress. Having a clear understanding of the mechanisms associated with the degradation of the HNE-modified proteins is essential for the development of strategies and for alleviating the unwanted effects of oxidative stress. The strategies which could be employed to decrease the effects of oxidative stress include enhancing antioxidant activity, as well as the use of nanozymes and/or specific inhibitors. One area which shows promise in reducing oxidative stress is protein design. However, more research is needed to improve the effectiveness and accuracy of this technique. This paper discusses the interplay of potential pathological factors and AD. In particular, it focuses on the effect of oxidative stress on the expression of the Aβ-degrading proteases through adduction of the degrading proteases caused by HNE. The paper also elucidates other strategies that can be used to alleviate the unwanted effects of oxidative stress on Aβ clearance. To improve the effectiveness and accuracy of protein design, we explain the application of quantum mechanical/molecular mechanical approach
The future of sustainable polar ship-based tourism
Get PDFOver the last couple of decades, polar tourism has significantly grown in the number of visitors and diversified in terms of the tourism activities offered. The COVID-19 pandemic brought polar tourism to a halt and has prompted researchers, operators and policy-makers alike to reflect on how Arctic and Antarctic tourism have developed, how they are being managed and governed and, importantly, how tourism operators influence polar socio-ecological systems. Given the dominance of ship-based tourism over other types of tourism in the Polar Regions, we discuss the cornerstones of how polar ship-based tourism has developed over the last 50 years and explore the relevant international and regional governance regimes in this article. We identify which positive and negative biophysical, socio-cultural and economic impacts arising from polar tourism have been identified by researchers. It is difficult, if not impossible, to disentangle impacts caused by tourism alone from those that result from the interactions of multiple pressures at all levels (local, regional and global), and more research is needed to develop reliable and effective indicators to monitor tourism impacts. In addition, a better understanding is needed about the role tourist experiences might play in potentially encouraging long-term positive behavioural changes among visitors to the Polar Regions. The COVID-19 pandemic has provided an important opportunity to review polar tourism development and management, and to ask whether an emphasis should be placed on ‘degrowth’ of the sector in the future
Bayesian modelling of phosphorus content in wheat grain using hyperspectral reflectance data
Get PDFBackground: As a result of the technological progress, the use of sensors for crop survey has substantially increased, generating valuable information for modelling agricultural data. Plant spectroscopy jointly with statistical modeling can potentially help to assess certain chemical components of interest present in plants, which may be laborious and expensive to obtain by direct measurements. In this research, the phosphorus content in wheat grain is modeled using reflectance information measured by a hyperspectral sensor at different wavelengths. A Bayesian procedure for selecting variables was used to identify the set of the most important spectral bands. Additionally, three different models were evaluated: the first model assumes that the observations are independent, the other two models assume that the observations are spatially correlated: one of the proposed models, assumes spatial dependence using a Conditionally Autoregressive Model (CAR), and the other through an exponential correlogram. The goodness of fit of the models was evaluated by means of the Deviance Information Criterion, and the predictive power is evaluated using cross validation.
Results: We have found that CAR was the model that best fits and predicts the data. Additionally, the selection variable procedure in the CAR model reveals which wavelengths in the range of 500–690 nm are the most important. Comparing the vegetative indices with the CAR model, it was observed that the average correlation of the CAR model exceeded that of the vegetative indices by 23.26%, − 1.2% and 22.78% for the year 2010, 2011 and 2012 respectively; therefore, the use of the proposed methodology outperformed the vegetative indices in prediction.
Conclusions: The proposal to predict the phosphorus content in wheat grain using Bayesian approach, reflect with the results as a good alternative
Simulating water and nitrogen runoff with APSIM
Get PDFTo determine the impact of potential reductions of terrain-targeted nitrogen (N) fertilisation rates on N losses a simulation study was carried out using the Agricultural Production Systems Simulator (APSIM). To simulate N runoff a simple approach was used, in which runoff is based on the N concentration in the soil solution and an extraction coefficient. Firstly, APSIM parameters that have the largest effect on runoff of water and N were determined for terrains with different slopes for a poorly drained silt loam. A sensitivity analysis was then conducted to assess the effect of soil hydraulic properties and soil organic carbon content on runoff losses. Finally, APSIM was set up to simulate pasture production and water and N dynamics (including pasture N uptake, leaching and N runoff) for a farm on rolling hills in South Canterbury, New Zealand. Two different fertilisation approaches were used, either scheduled or based on the aboveground N concentration of the pasture. For the poorly drained silt loam, the rainfall intensity and the surface conductance had the highest effect on the amount of water lost by runoff. Soil hydraulic conductivity at saturation and field capacity, as well as plant available water content also controlled runoff of water and N, while the organic carbon content of the topsoil had less effect on N runoff. Both the extraction coefficient and the depth considered to exchange N with the runoff water affected the amount of N lost via runoff. Using the aboveground pasture N concentration prior to fertilisation had positive effects on pasture yield and reduced N runoff losses
Vision in the Western Flower Thrips: analysis of their behavioural response to colour and study of their compound eyes : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
No full textThe western flower thrips (WFT), Frankliniella occidentalis (Pergande, 1895), (Thysanoptera) are tiny insects with a body length of around 1 mm and commonly known as a worldwide, plant virus-transmitting pest causing economic losses in many important crops. Extensive research has been done regarding WFT biology and behaviour, including on their response to coloured traps for monitoring and pest management. However, little effort has been given in that case to understand how their visual system uses colour to guide their behaviour. Consequently, the different levels of response that have been recorded amongst published studies for WFT to the most attractive colours of yellow (570 - 590 nm), blue (450 - 470 nm), and UV-light (< 400 nm) remains unexplained at the fundamental level affecting applied outcomes. Effectively, intra-specific variation is accepted at the expense of suboptimal trap systems that remain difficult to improve across the species. Ultimately, using colour to optimise the attractiveness of traps, to the extent that they could be used to reduce populations as a means of control, continues to be elusive. Therefore, the overall aims of the thesis were to have a better understanding of how colour vision guides WFT behaviour in the context of attractive colours, including their spatial and directional movement and also to develop relevant knowledge about WFT eye anatomy as a fundamental aspect that contributes to behaviour.
The debate regarding WFT behavioural response to colour was addressed here by isolating key variables such as light wavelength and intensity with the use of LEDs, as these factors are confounded in studies utilising coloured sticky and water traps which rely on light reflection. Experiments producing end point data of WFT landing on a sticky LED surface were conducted in highly controlled conditions in a wind tunnel where thrips were free to fly. With the laboratory colony of WFT used for this work, the results confirmed that WFT landings varied with colour, with UV-A and yellow obtaining higher landings than any other evaluated colour, including blue. No significant effect was found when intensity of the LEDs was increased except for UV-A light which had a decrease in number of landings with higher light intensity. With a focus on WFT attraction to blue and yellow, it was shown here for the first time that WFT response to these colours can vary intraspecifically when evaluated under the same experimental conditions and methods. This suggests that population effects may also be the source of variation causing the different conclusions found in the literature as to the most attractive colour.
Real-time 3D tracking and high-speed videography was used to examine in more detail the effect of UV-A light as well as paired colours adjacent to each other, allowing landing and directional flight behaviour of WFT in close proximity to the LEDs to be recorded. Results showed that a positive interaction with the UV-A and yellow combination elicited the highest number of landings and flight time. Conversely, a negative interaction was found when yellow and blue were paired together with decreased number of landings and flight time. Tracking data also suggest that WFT might use different colours at different distances with differences in the landing pattern found between UV-A light and colours of longer wavelength like green and yellow. In addition, the data suggest that in the specific set up used in the experiments, a ‘decision’ to land is made at around 70-80 mm from the LED.
Finally, several microscopy and imaging methods such as electron, fluorescence and light microscopy together with X-ray microtomography were used to describe the anatomy and morphology of WFT miniaturised eyes and reveal previously unknown information about their visual system. Together the data infer that WFT eyes are of the apposition type with 60 ommatidia on each eye. In addition, the ultrastructure of their eyes indicate various anatomical and structural adaptations from which it is argued that they likely prioritize light sensitivity over visual acuity. Despite the size constraints of WFT as a micro insect (with body length of ~ 1 mm), their compound eyes present a functional visual system composed of cornea, crystalline cone and at least seven photoreceptor cells that form a fused rhabdom. In addition, WFT present an acute zone in the fronto-ventral part of their eyes and possess putative filter pigments that may help in spectral tuning of underlying photoreceptors.
Overall, new knowledge from the combined aspects of this study is discussed in the context of the role that vision and colour play in the ecology of WFT and as a contribution to studies focussed on improved applied outcomes
Understanding your research data: Using statistics for sport and exercise science
No full textTalk given at the Faculty of Medicine, Khon Kaen University
Complexity, crash and collapse of chaos: Clues for designing sustainable systems, with focus on grassland-based systems
Get PDFTerms such as system crash, collapse of chaos and complexity can help one understand change, also in biological, socio-economic and technical systems. These terms need, however, explanation for fruitful dialogue on design of sustainable systems. We start this paper on Grass Based (GB) systems, therefore, dwelling on these terms and notions as review for the insiders and to help interested ‘outsiders’. We also stress the need to use additional and/or new paradigms for understanding of the nature of nature. However, we show that many such ‘new’ paradigms were known for long time around the globe among philosophers and common men, giving reason to include quotes and examples from other cultures and eras. In the past few centuries, those paradigms have become hidden, perhaps, under impressive but short-term successes of more linear paradigms. Therefore, we list hang-ups on paradigms of those past few centuries. We then outline what is meant by ‘GB systems’, which exist in multiple forms/‘scapes’. Coping with such variation is perhaps the most central aspect of complexity. To help cope with this variation, the different (GB) systems can be arranged on spatial, temporal, and other scales in such a way that the arrangements form logical sequences (evolutions) of stable states and transitions of Complex Adaptive Systems (CAS). Together with other ways to handle complexity, we give examples of such arrangements to illustrate how one can (re-)imagine, (re-)cognize and manage initial chaotic behaviors and eventual ‘collapse’ of chaos into design and/or emergence of new systems. Then, we list known system behaviors, such as predator–prey cycles, adaptive cycles, lock-in, specialization and even tendency to higher (or lower) entropy. All this is needed to understand changes in management of evolving GB into multi-scapes. Integration of disciplines and paradigms indicates that a win-win is likely to be exception rather than rule. With the rules given in this paper, one can reset teaching, research, rural development, and policy agendas in GB-systems and other areas of life
Do silvopastoral management practices affect biological pest control in oil palm plantations?
No full textThe reliance of conventional oil palm production on agrochemicals to control understory vegetation has caused devastating impacts on the environment. Overuse of chemical herbicides leads to the decline of native biodiversity and production-related ecosystem services, including biological pest control. In contrast to herbicide applications, livestock integration is a chemical-free approach to eradicate weeds without negative consequences on the environment. In this sentinel prey experiment, we assessed the predation pressure (based upon the number of bite marks left by natural predators such as arthropods, birds, and mammals) in three oil palm plantations with different weeding practices (i.e., rotational grazing, free-range grazing, and conventional weeding) located on the south-west part of Peninsular Malaysia. We also investigated the effects of site level characteristics on the predation pressures of artificial caterpillars. Across all types of weeding systems, we found that the majority of the predation attempts on the deployed artificial caterpillars were made by arthropods (532 attempts), whereas mammals (66 attempts) and birds (60 attempts) played much smaller roles. Our results showed that predation pressures were consistent across sites indicating that oil palm-cattle integrated plantations (either free-range or rotational grazing systems) would experience similar level of pest control services as conventional herbicide-sprayed plantations. Our results also indicate the influence of site-level habitat variables (i.e., mean of palm heights, canopy cover, and elevation) on predation pressures. Our results suggest that livestock-oil palm integration may sustain natural predation with little or no herbicide input
Activity of apple endophytic fungi to control Neonectria ditissima infection of apple : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
No full textApple (Malus domestica) is one of the most important fruit crops in New Zealand. European canker, caused by Neonectria ditissima, is an economically important disease in apple-producing regions worldwide. Currently, the disease is managed by the application of fungicides and the removal of canker-infected branches. There is growing concern regarding the potential health risks of chemical residues on fruit for human consumption and environmental pollution. Also, the development of fungicide-resistant strains of N. ditissima is a risk for apple production. In addition, canker pruning is labour-intensive and costly. Biological control of plant pathogens utilising endophytic microorganisms has received increased attention in recent years as an eco-friendly and effective control mechanism for many plant diseases. This study aimed to identify apple fungal endophytes with biocontrol efficacy against N. ditissima. It was achieved by i) investigation of the in vitro activity of fungal isolates against N. ditissima using plate-based bioassays, ii) investigation of the in vivo colonisation potential and pathogenicity of endophytes, and iii) evaluation of the in planta biocontrol activity of selected isolates using shoot assays.
The three hundred and eleven fungal endophytes used in this research project were isolated from apple stem and leaf tissues. A preliminary dual-plate assay was conducted to investigate the activity of these fungal isolates to reduce the in vitro growth of N. ditissima, with 37 isolates exhibiting antagonism to N. ditissima. Based on 16S rRNA gene sequencing, 37 isolates were identified into 12 genera: Biscogniauxia (n=8), Diaporthe (n=8), Trichoderma (n=5), Chaetomium (n=4), Paraphaeosphaeria (n=1), Epicoccum (n=2), Neosetophoma (n=2), Xylaria (n=1), Hansfordia (n=1), Penicillium (n=1), Fusarium (n=1), Colletotrichum (n=1), and an additional class, Sordariomycetes, and an unidentified fungal endophyte isolate. These isolates were tested further for the production of volatile and non-volatile inhibitory metabolites and siderophores related to their potential bioactivity in vitro and in planta. The volatile assay revealed that 24 isolates produced volatile compounds that inhibited the mycelium growth of N. ditissima compared to the untreated control. Additionally, agar amended with a 50% culture filtrate of six isolates inhibited the in vitro growth of N. ditissima by over 20%. Further, 15 isolates were shown to produce siderophores in modified chrom-azurol S agar (CAS) assay.
The colonisation and pathogenicity ability in planta of 37 isolates was examined in ‘Royal Gala’ detached shoots and additionally ‘Royal Gala’ and ‘Braeburn’ fruit. Results indicated that 24 isolates were non-pathogenic to apple shoots and fruit. Of these 24 isolates, 22 were reisolated from the inoculated detached shoots. Almost all the isolates (36 out of 37) produced at least one of the enzymes assayed; amylase (20/37 isolates), cellulase (15/37 isolates), pectinase (25/37 isolates), protease (26/37 isolates) and xylanase (13/37 isolates).
The in planta biocontrol activity of four isolates (one each Biscogniauxia sp., Neosetophoma sp., Trichoderma sp. and Paraphaeosphaeria sp.) that showed in vitro antagonism against N. ditissima with good colonisation capability were evaluated using in vivo detached shoot assays. The results of the autumn experiment indicated that inoculation of 7 days prior to the N. ditissima with either of the two isolates (Trichoderma sp. and Paraphaeosphaeria sp.) effectively reduced N. ditissima colonisation in the detached shoot tissues. The presence and absence of N. ditissima in the shoot tissue, with or without endophytes, were assessed using isolation media and PCR. The colony of N. ditissima was recovered from tissue up to 50 mm from the inoculation point in both the upward and downward directions. In PCR analysis, N. ditissima was detected up to 30 mm beyond the inoculation point in asymptomatic tissues harvested 30 days after inoculation. The two selected endophytes, T. atroviride isolate FE3 and P. neglecta isolate FE9, were further tested for their ability to reduce N. ditissima colonisation of intact shoots on potted ‘Royal Gala’ and ‘Braeburn’ trees under shade house conditions. The results indicated that P. neglecta isolate FE9 and T. atroviride sp. isolate FE3 did not significantly reduce the colonisation of N. ditissima in the shoot tissues.
Overall, this is the first New Zealand study that focused on investigating the biocontrol capabilities of endophytic fungal isolates against N. ditissima. This study provides information on the assessment of potential antagonistic fungal endophytes, their enzymatic activity and colonisation ability in asymptomatic apple shoot tissues
We’re all in this together? Community resilience and recovery in Kaikōura following the 2016 Kaikōura-Hurunui earthquake
Get PDFThe magnitude 7.8 earthquake that struck North Canterbury, on the east coast of New Zealand’s South Island on 14 November 2016 had significant impacts and implications for the community of Kaikōura and surrounding settlements. The magnitude and scope of this event has resulted in extensive and ongoing geological and geophysical research into the event. The current paper complements this research by providing a review of existing social science research and offering new analysis of the impact of the earthquake and its aftermath on community resilience in Kaikōura over the past five years. Results demonstrate the significant economic implications for tourism, and primary industries. Recovery has been slow, and largely dependent on restoring transportation networks, which helped catalyse cooperation among local hospitality providers. Challenges remain, however, and not all sectors or households have benefited equally from post-quake opportunities, and long-term recovery trajectories continue to be hampered by COVID-19 pandemic. The multiple ongoing and future stressors faced by Kaikōura require integrated and equitable approaches in order to build capability and capacity for locally based development pathways to ensure long-term community resilience