Veterinary Science Collected Works - Research Publications
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ItemA disrupted transsulphuration pathway results in accumulation of redox metabolites and induction of gametocytogenesis in malaria(NATURE PORTFOLIO, 2017-01-16)Intra-erythrocytic growth of malaria parasite is known to induce redox stress. In addition to haem degradation which generates reactive oxygen species (ROS), the parasite is also thought to efflux redox active homocysteine. To understand the basis underlying accumulation of homocysteine, we have examined the transsulphuration (TS) pathway in the parasite, which is known to convert homocysteine to cysteine in higher eukaryotes. Our bioinformatic analysis revealed absence of key enzymes in the biosynthesis of cysteine namely cystathionine-β-synthase and cystathionine-γ-lyase in the parasite. Using mass spectrometry, we confirmed the absence of cystathionine, which is formed by enzymatic conversion of homocysteine thereby confirming truncation of TS pathway. We also quantitated levels of glutathione and homocysteine in infected erythrocytes and its spent medium. Our results showed increase in levels of these metabolites intracellularly and in culture supernatants. Our results provide a mechanistic basis for the long-known occurrence of hyperhomocysteinemia in malaria. Most importantly we find that homocysteine induces the transcription factor implicated in gametocytogenesis namely AP2-G and consequently triggers sexual stage conversion. We confirmed this observation both in vitro using Plasmodium falciparum cultures, and in vivo in the mouse model of malaria. Our study implicates homocysteine as a potential physiological trigger of gametocytogenesis.
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ItemRenewal ecology: conservation for the Anthropocene(WILEY, 2017-09)The global scale and rapidity of environmental change is challenging ecologists to reimagine their theoretical principles and management practices. Increasingly, historical ecological conditions are inadequate targets for restoration ecology, geographically circumscribed nature reserves are incapable of protecting all biodiversity, and the precautionary principle applied to management interventions no longer ensures avoidance of ecological harm. In addition, human responses to global environmental changes, such as migration, building of protective infrastructures, and land use change, are having their own negative environmental impacts. We use examples from wildlands, urban, and degraded environments, as well as marine and freshwater ecosystems, to show that human adaptation responses to rapid ecological change can be explicitly designed to benefit biodiversity. This approach, which we call “renewal ecology,” is based on acceptance that environmental change will have transformative effects on coupled human and natural systems and recognizes the need to harmonize biodiversity with human infrastructure, for the benefit of both.
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ItemHigh-throughput physiological phenotyping and screening system for the characterization of plant-environment interactions(WILEY, 2017-02)We present a simple and effective high-throughput experimental platform for simultaneous and continuous monitoring of water relations in the soil-plant-atmosphere continuum of numerous plants under dynamic environmental conditions. This system provides a simultaneously measured, detailed physiological response profile for each plant in the array, over time periods ranging from a few minutes to the entire growing season, under normal, stress and recovery conditions and at any phenological stage. Three probes for each pot in the array and a specially designed algorithm enable detailed water-relations characterization of whole-plant transpiration, biomass gain, stomatal conductance and root flux. They also enable quantitative calculation of the whole plant water-use efficiency and relative water content at high resolution under dynamic soil and atmospheric conditions. The system has no moving parts and can fit into many growing environments. A screening of 65 introgression lines of a wild tomato species (Solanum pennellii) crossed with cultivated tomato (S. lycopersicum), using our system and conventional gas-exchange tools, confirmed the accuracy of the system as well as its diagnostic capabilities. The use of this high-throughput diagnostic screening method is discussed in light of the gaps in our understanding of the genetic regulation of whole-plant performance, particularly under abiotic stress.
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ItemWater Experts' Perception of Risk for New and Unfamiliar Water Projects(MDPI AG, 2017-12)In the context of a changing urban environment and increasing demand due to population growth, alternative water sources must be explored in order to create future water security. Risk assessments play a pivotal role in the take-up of new and unfamiliar water projects, acting as a decision-making tool for business cases. Perceptions of risk ultimately drive risk assessment processes, therefore providing insight into understanding projects that proceed and those that do not. Yet there is limited information on the risk perceptions water professionals have of new and unfamiliar water projects. In this study, 77 water professionals were surveyed from across the Melbourne metropolitan water industry to examine risk perceptions over a range of different, unfamiliar water projects. The qualitative data was thematically analysed, resulting in a number of risk perception factors for each hypothetical project. Risk factors that recurred most frequently are those that relate to community backlash and to the reputation of the organisation. These social risk perceptions occurred more frequently than other more technical risks, such as operational risks and process-related risks. These results were at odds with the existing literature assessing risk perceptions of business-as-usual projects, which presented cost as the key risk attribute. This study sheds light on the perceived nature of new and unfamiliar processes in the water sector, providing an understanding that public perceptions do matter to experts involved in water infrastructure decision-making.
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ItemA modified assay for the enumeration of ascaris eggs in fresh raw sewage(ELSEVIER SCIENCE BV, 2017)Soil-transmitted helminths (STHs) pose a significant public health problem, infecting approximately 2 billion people globally. Despite relatively low prevalence in developed countries, the removal of STHs from wastewater remains crucial to allow the safe use of biosolids or recycled water for agriculture. Wastewater helminth egg count data can contribute to an assessment of the need for, or success of, a parasite management program. Although the World Health Organisation (WHO) has recommended a standard method for counting helminth eggs in raw sewage based on the method of Bailenger (Ayres et al., 1996), the method generally results in low percentage egg recoveries. Given the importance of determining the presence of STHs, it is essential to develop novel techniques that optimise the recovery rate of eggs from raw sewage. In the present study: •The method described by Bowman et al. (2003) was optimized for the concentration and enumeration of helminth eggs in raw sewage from municipal sewage treatment plants.•The method is simple and reproducible and recovers a greater percentage of helminth eggs compared to the WHO method.
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ItemLong-term Effect of Intra-Row Spacing on Growth and Productivity of Super-High Density Hedgerow Olive Orchards (cv. Arbequina).(Frontiers Media SA, 2017)Intra-row spacing is known to determine early productivity of super-high density olive orchards depending on growing conditions, cultivar growth characteristics, planting geometry and subsequent pruning management but few experiments have been carried out in this olive hedgerow orchard design. In 2008 an experiment of 4-m spaced hedgerows was established with 8 intra-row spacings (from 1.0 to 2.5 m) in Toledo (Spain) resulting in orchards of density ranging from 2,500 to 1,000 trees ha-1. Tree growth was evaluated as height, trunk diameter and leaf area during the first 4 years. Hedgerow porosity was calculated from the 4th until the 9th year. In the 8th year hedgerow height, width, leaf area and branch angles were measured. Olives were harvested from 3rd to 9th year for measurements of fruit characteristics and productivity. Tree growth was not affected by intra-row spacing during the first 4 years. In the 8th year leaf area, external surface area and volume per tree were significantly greater in the more spaced trees; but hedgerow characteristics of leaf area per hectare, number of effective leaf layers horizontally through the hedgerow, and leaf density were not affected. In the more spaced trees insertion angles of branches to the vertical were significantly greater, mainly in the lower canopy. Intra-row spacing did not affect fruit characteristics. Oil production ha-1 decreased linearly with spacing during the first 4 harvests while production per tree increased significantly with spacing after the 3rd harvest. As a result, oil production ha-1 from the seven harvests combined only increased for tree spacing less than 1.2 m; wider spacing had no effect. Annual oil production ha-1 increased linearly as porosity was reduced by greater tree density and canopy development along the seasons.
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ItemMutation of a Conserved Nuclear Export Sequence in Chikungunya Virus Capsid Protein Disrupts Host Cell Nuclear Import.(MDPI AG, 2017-10-20)Transmitted by mosquitoes; chikungunya virus (CHIKV) is responsible for frequent outbreaks of arthritic disease in humans. CHIKV is an arthritogenic alphavirus of the Togaviridae family. Capsid protein, a structural protein encoded by the CHIKV RNA genome, is able to translocate to the host cell nucleus. In encephalitic alphaviruses nuclear translocation induces host cell shut off; however, the role of capsid protein nuclear localisation in arthritogenic alphaviruses remains unclear. Using replicon systems, we investigated a nuclear export sequence (NES) in the N-terminal region of capsid protein; analogous to that found in encephalitic alphavirus capsid but uncharacterised in CHIKV. The chromosomal maintenance 1 (CRM1) export adaptor protein mediated CHIKV capsid protein export from the nucleus and a region within the N-terminal part of CHIKV capsid protein was required for active nuclear targeting. In contrast to encephalitic alphaviruses, CHIKV capsid protein did not inhibit host nuclear import; however, mutating the NES of capsid protein (∆NES) blocked host protein access to the nucleus. Interactions between capsid protein and the nucleus warrant further investigation.
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ItemMetrics and the Scientific Literature: Deciding What to Read.(Wiley, 2017-05)
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ItemInterobserver Variation in the Diagnosis of Neurologic Abnormalities in the Horse(WILEY, 2017-11)BACKGROUND: The diagnosis of equine protozoal myeloencephalitis (EPM) relies heavily on the clinical examination. The accurate identification of neurologic signs during a clinical examination is critical to the interpretation of laboratory results. OBJECTIVE: To investigate the level of agreement between board-certified veterinary internists when performing neurologic examinations in horses. ANIMALS: Ninety-seven horses admitted to the Veterinary Teaching Hospital at The Ohio State University from December 1997 to June 1998. METHODS: A prospective epidemiologic research design was used. Horses enrolled in the study were examined by the internist responsible for care of the horse, and later by an internist who was not aware of the presenting complaint or other patient history. Data were analyzed by descriptive statistics, and kappa (K) statistics were calculated to assess interobserver agreement. RESULTS: Ninety-seven horses were enrolled in the study. Overall, examiners, also referred to as observers, agreed that 60/97 (61.9%) were clinically abnormal, 21/97 (21.6%) were clinically normal, and the status of 16/97 (16.5%) of horses was contested. There was complete agreement among the examiners with regard to cranial nerve signs and involuntary movements. Disagreement involving severity of clinical signs occurred in 31 horses, and 25 of those horses (80.6%) were considered either normal or mildly affected by the primary observer. When examining the results of all paired clinical examinations for 11 different categories, there was wide variability in the results. When examiners rated the presence or absence of any neurologic abnormalities, lameness, or ataxia, the agreement among observers was either good or excellent for 80% of horses. When assessing truncal sway, the agreement among observers was good or excellent for 60% of the horses. When examining the horses for asymmetry of deficits, agreement was either good or excellent for 40% of the horses. Agreement among observers was excellent or good for only 20% of the horses when assessing muscle atrophy, spasticity (hypermetria), and overall assessment of the severity of neurologic abnormalities. CONCLUSIONS AND CLINICAL IMPORTANCE: This study underscores the subjectivity of the neurologic examination and demonstrates a reasonable level of agreement that may be achieved when different clinicians examine the same horse.
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ItemTarget product profiles for the diagnosis of Taenia solium taeniasis, neurocysticercosis and porcine cysticercosis(PUBLIC LIBRARY SCIENCE, 2017-09)Target Product Profiles (TPPs) are process tools providing product requirements to guide researchers, developers and manufacturers in their efforts to develop effective and useful products such as biologicals, drugs or diagnostics. During a WHO Stakeholders Meeting on Taenia solium diagnostics, several TPPs were initiated to address diagnostic needs for different stages in the parasite's transmission (taeniasis, human and porcine cysticercosis). Following the meeting, draft TPPs were completed and distributed for consultation to 100 people/organizations, including experts in parasitology, human and pig cysticercosis, diagnostic researchers and manufacturers, international organizations working with neglected or zoonotic diseases, Ministries of Health and Ministries of Livestock in some of the endemic countries, WHO regional offices and other interested parties. There were 53 respondents. All comments and feedback received were considered and discussions were held with different experts according to their area of expertise. The comments were consolidated and final TPPs are presented here. They are considered to be live documents which are likely to undergo review and updating in the future when new knowledge and technologies become available.