33 research outputs found
A rapid and sensitive intracellular flow cytometric assay to identify Theileria parva infection within target cells
Theileria parva is an intracellular protozoan parasite transmitted by ticks that causes a fatal lymphoproliferative disease of cattle known as East Coast Fever. Vaccination against the disease currently relies on inoculation of the infective sporozoite stage of the parasite and simultaneous treatment with long-acting formulations of oxytetracycline. Sporozoites are maintained as frozen stabilates of triturated infected ticks and the method requires accurate titration of stabilates to determine appropriate dose rates. Titration has traditionally been undertaken in cattle and requires large numbers of animals because of individual variation in susceptibility to infection. An alternative tissue culture-based method is laborious and time consuming. We have developed a flow cytometric method for quantifying the infectivity of sporozoite stabilates in vitro based on the detection of intracellular parasite antigen. The method allows clear identification of parasitized cells with a high degree of sensitivity and specificity. Analysis of infected cells between 48 and 72 h post-infection clearly defines the potential transforming capability of different stabilates
Scotlandâs biodiversity progress to 2020 Aichi Targets:Conserving genetic diversity- development of a national approach for addressing Aichi Biodiversity Target 13 that includes wild species
Aichi Target 13 (T13) focuses on the conservation of genetic diversity. â˘Major challenges in implementing T13 are that the type of genetic diversity to conserve is not clearly defined, and that key issues in genetic conservation vary across different sectors (e.g., forestry vs agriculture vs other species of socio-economic importance). â˘In Scotland and the UK more widely, baseline mechanisms are well established for assessing and reporting on genetic diversity in species of agricultural importance (e.g., rare livestock breeds, crop wild relatives), and a methodology has been established for ornamental plants. â˘A new UK Strategy for Forest Genetics Resources was launched in 2019, creating a framework for linking forest trees into T13 reporting. â˘However, there is no clear strategy to deal with âother species of socio-economic importanceâ in Scotland, the UK or indeed elsewhere, and addressing this gap is the major focus of this report. â˘There is a lack of guidance for identifying focal species of socio-economic importance, and no clear mechanism for addressing T13 for these species once they have been identified. â˘To address this, we have identified a set of criteria for defining terrestrial and freshwater species of socio-economic importance in Scotland, and selected an initial list of 26 species. â˘The criteria applied were: -National conservation priority wild species. -Species of national cultural importance. -Species providing key ecosystem services. -Species of importance for wild harvesting (food and medicine). -Economically important game species. â˘We then developed a simple, readily applicable scorecard method for assessing risks to the conservation of genetic diversity in these species. â˘The scorecard approach is not dependent on prior genetic knowledge, and instead uses structured expert opinion assessments of whether: -Demographic declines are likely to lead to loss of genetic diversity (genetic erosion). -Hybridisation is likely to lead to undesirable replacement of genetic diversity. -Restrictions to regeneration/turnover are likely to impede evolutionary change. â˘For plant species where seed-banking is a viable mechanism for holding genetic resources ex situ,we also report on the representativeness of these ex situ collections. â˘Overall, this scorecard provides a mechanism for incorporating âother species of socio-economic importanceâ into T13 actions and reporting. â˘Furthermore, its application is not restricted to Aichi T13 as the approach is designed as a generic scorecard for genetic diversity. It is thus relevant to post-2020 CBD targets focusing on genetic diversity. â˘Future priorities include: -Extension to other species of socio-economic, commercial and cultural importance (with the inclusion of marine species being a particularly high priority). -Harmonising genetic conservation strategies between sectors (drawing on commonalities), whilst minimising disruption of existing well-established methodologies within sectors. -Greater incorporation of genomic data into monitoring genetic diversity (particularly in the agricultural and forestry sectors where data availability is potentially high)
Soil Water Assessment Tool (SWAT) simulated hydrological impacts of land use change from temperate grassland to energy crops:A case study in western UK
When considering the largeâscale deployment of bioenergy crops, it is important to understand the implication for ecosystem hydrological processes and the influences of crop type and location. Based on the potential for future land use change (LUC), the 10,280 km2 West Wales Water Framework Directive River Basin District (UK) was selected as a typical grassland dominated district, and the Soil & Water Assessment Tool (SWAT) hydrology model with a geographic information systems interface was used to investigate implications for different bioenergy deployment scenarios. The study area was delineated into 855 subâbasins and 7,108 hydrological response units based on rivers, soil type, land use, and slope. Changes in hydrological components for two bioenergy crops (Miscanthus and short rotation coppice, SRC) planted on 50% (2,192 km2) or 25% (1,096 km2) of existing improved pasture are quantified. Across the study area as a whole, only surface runâoff with SRC planted at the 50% level was significantly impacted, where it was reduced by up to 23% (during April). However, results varied spatially and a comparison of annual means for each subâbasin and scenario revealed surface runâoff was significantly decreased and baseflow significantly increased (by a maximum of 40%) with both Miscanthus and SRC. Evapotranspiration was significantly increased with SRC (at both planting levels) and water yield was significantly reduced with SRC (at the 50% level) by up to 5%. Effects on streamflow were limited, varying between â5% and +5% change (compared to baseline) in the majority of subâbasins. The results suggest that for mesic temperate grasslands, adverse effects from the drying of soil and alterations to streamflow may not arise, and with surface runâoff reduced and baseflow increased, there could, depending on crop location, be potential benefits for flood and erosion mitigation
Limited diversity associated with duplicated class II MHC-DRB genes in the red squirrel population in the United Kingdom compared with continental Europe
The red squirrel (Sciurus vulgaris) population in the United Kingdom has declined over the last century and is now on the UK endangered species list. This is the result of competition from the eastern grey squirrel (S. carolinensis) which was introduced in the 19th century. However, recent evidence suggests that the rate of population decline is enhanced by squirrelpox disease, caused by a viral infection carried asymptomatically by grey squirrels but to which red squirrels are highly susceptible. Population genetic diversity provides some resilience to rapidly evolving or exotic pathogens. There is currently no data on genetic diversity of extant UK squirrel populations with respect to genes involved in disease resistance. Diversity is highest at loci involved in the immune response including genes clustered within the major histocompatibility complex (MHC). Using the class II DRB locus as a marker for diversity across the MHC region we genotyped 110 red squirrels from locations in the UK and continentalEurope. Twenty four Scvu-DRB alleles at two functional loci; Scvu-DRB1 and Scvu- DRB2, were identified. High levels of diversity were identified at both loci in the continental populations. In contrast, no diversity was observed at the Scvu-DRB2 locus in the mainland UK population while a high level of homozygosity was observed at the Scvu-DRB1 locus. The red squirrel population in the UK appears to lack the extensive MHC diversity associated with continental populations, a feature which may have contributed to their rapid decline
Fine-mapping host genetic variation underlying outcomes to Mycobacterium bovis infection in dairy cows
Abstract Background Susceptibility to Mycobacterium bovis infection in cattle is governed in part by host genetics. However, cattle diagnosed as infected with M. bovis display varying signs of pathology. The variation in host response to infection could represent a continuum since time of exposure or distinct outcomes due to differing pathogen handling. The relationships between host genetics and variation in host response and pathological sequelae following M. bovis infection were explored by genotyping 1966 Holstein-Friesian dairy cows at 538,231 SNPs with three distinct phenotypes. These were: single intradermal cervical comparative tuberculin (SICCT) test positives with visible lesions (VLs), SICCT-positives with undetected visible lesions (NVLs) and matched controls SICCT-negative on multiple occasions. Results Regional heritability mapping identified three loci associated with the NVL phenotype on chromosomes 17, 22 and 23, distinct to the region on chromosome 13 associated with the VL phenotype. The region on chromosome 23 was at genome-wide significance and candidate genes overlapping the mapped window included members of the bovine leukocyte antigen class IIb region, a complex known for its role in immunity and disease resistance. Chromosome heritability analysis attributed variance to six and thirteen chromosomes for the VL and NVL phenotypes, respectively, and four of these chromosomes were found to explain a proportion of the phenotypic variation for both the VL and NVL phenotype. By grouping the M. bovis outcomes (VLs and NVLs) variance was attributed to nine chromosomes. When contrasting the two M. bovis infection outcomes (VLs vs NVLs) nine chromosomes were found to harbour heritable variation. Regardless of the case phenotype under investigation, chromosome heritability did not exceed 8% indicating that the genetic control of bTB resistance consists of variants of small to moderate effect situated across many chromosomes of the bovine genome. Conclusions These findings suggest the host genetics of M. bovis infection outcomes is governed by distinct and overlapping genetic variants. Thus, variation in the pathology of M. bovis infected cattle may be partly genetically determined and indicative of different host responses or pathogen handling. There may be at least three distinct outcomes following M. bovis exposure in dairy cattle: resistance to infection, infection resulting in pathology or no detectable pathology
Breadth of the CD4+ T cell response to Anaplasma marginale VirB9-1, VirB9-2 and VirB10 and MHC class II DR and DQ restriction elements
MHC class II molecules influence antigen-specific CD4(+) T-lymphocyte responses primed by immunization and infection. CD4(+) T-cell responses are important for controlling infection by many bacterial pathogens including Anaplasma marginale, and are observed in cattle immunized with the protective A. marginale outer membrane (OM) vaccine. Immunogenic proteins that comprise the protective OM vaccine include type IV secretion system (T4SS) proteins VirB9-1, VirB9-2, and VirB10, candidates for inclusion in a multi-epitope vaccine. Our goal was to determine the breadth of the VirB9-1, VirB9-2, and VirB10 T-cell response and MHC class II restriction elements in six cattle with different MHC class II haplotypes, defined by DRB3, DQA, and DQB allele combinations for each animal. Overlapping peptides spanning each T4SS protein were tested in T-cell proliferation assays with autologous antigen presenting cells (APC) and artificial APC expressing combinations of bovine DR and DQ molecules. Twenty immunostimulatory peptides were identified; three representing two or more epitopes in VirB9-1, ten representing eight or more epitopes in VirB9-2, and seven representing seven or more epitopes in VirB10. Of eight DRA/DRB3 molecules, four presented 15 peptides, which was biased as DRA/DRB3*1201 presented ten and DRA/DRB3*1101 presented four peptides. Four DQA/DQB molecules composed of two intrahaplotype and two interhaplotype pairs presented seven peptides, of which five were uniquely presented by DQ molecules. In addition,three functional mixed isotype (DQA/DRB3) restriction elements were identified. The immunogenicity and broad MHC class II presentation of multiple VirB9-1, VirB9-2, and VirB10 peptide epitopes justify their testing as a multi-epitope vaccine against A. marginale
Genomic organisation and allelic diversity within coding and non-coding regions of the Ovar-DRB1 locus
Edinburgh Research Explorer A rapid and sensitive intracellular flow cytometric assay to identify Theileria parva infection within target cells
A rapid and sensitive intracellular flow cytometric assay to identify Theileria parva infection within target cells Citation for published version: Rocchi, MS, Ballingall, KT, Ngugi, D, MacHugh, N & McKeever, D 2008, 'A rapid and sensitive intracellular flow cytometric assay to identify Theileria parva infection within target cells ' Parasitology, vol 135, no. 2, pp. 195-201., 10.1017 General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. SUMMARY Theileria parva is an intracellular protozoan parasite transmitted by ticks that causes a fatal lymphoproliferative disease of cattle known as East Coast Fever. Vaccination against the disease currently relies on inoculation of the infective sporozoite stage of the parasite and simultaneous treatment with long-acting formulations of oxytetracycline. Sporozoites are maintained as frozen stabilates of triturated infected ticks and the method requires accurate titration of stabilates to determine appropriate dose rates. Titration has traditionally been undertaken in cattle and requires large numbers of animals because of individual variation in susceptibility to infection. An alternative tissue culture-based method is laborious and time consuming. We have developed a flow cytometric method for quantifying the infectivity of sporozoite stabilates in vitro based on the detection of intracellular parasite antigen. The method allows clear identification of parasitized cells with a high degree of sensitivity and specificity. Analysis of infected cells between 48 and 72 h post-infection clearly defines the potential transforming capability of different stabilates