The genetic basis of variation in bovine tuberculosis infection, progression and diagnosis in a wild animal host

Parasites are ubiquitous in wild animal populations and have wide ranging effects on the health, fitness and eco-evolutionary dynamics of their host populations. To counter parasites, hosts have evolved a myriad of defence strategies, but individuals vary considerably in the efficacy of these strategies, and so, in their susceptibility to infection. While variation can generally be viewed as stemming from genetic and environmental effects, we currently have little knowledge of their relative importance in wild and unmanaged host populations. In this thesis, I use long-term mark-recapture data on a population of European badgers (Meles meles) to examine the genetic basis of variation in bovine tuberculosis infection and its progression. I first estimate a genetic pedigree and characterise variation in extra-group paternity in the population (Chapter 2). Then, adopting a pedigree-based quantitative genetic approach, I investigate the relative importance of genetic and social environmental sources of variation in bTB infection status (Chapter 3). Thirdly, I characterise associations between body weight and bTB infection and test for variation in host tolerance (Chapter 4). And finally, I examine the genetic basis of (co)variation in and among four diagnostic test responses, representing different aspects of host immune function (Chapter 5). Taken together, this work provides novel insight into the genetic architecture of bovine tuberculosis infection in a wild host species, and the evolutionary potential of immune traits in the wild

Genetic Variability and Structuring of Arctic Charr (Salvelinus alpinus) Populations in Northern Fennoscandia

Variation in presumably neutral genetic markers can inform us about evolvability, historical effective population sizes and phylogeographic history of contemporary populations. We studied genetic variability in 15 microsatellite loci in six native landlocked Arctic charr (Salvelinus alpinus) populations in northern Fennoscandia, where this species is considered near threatened. We discovered that all populations were genetically highly (mean F-ST approximate to 0.26) differentiated and isolated from each other. Evidence was found for historical, but not for recent population size bottlenecks. Estimates of contemporary effective population size (N-e) ranged from seven to 228 and were significantly correlated with those of historical N-e but not with lake size. A census size (N-C) was estimated to be approximately 300 individuals in a pond (0.14 ha), which exhibited the smallest N-e (i.e. N-e/N-C = 0.02). Genetic variability in this pond and a connected lake is severely reduced, and both genetic and empirical estimates of migration rates indicate a lack of gene flow between them. Hence, albeit currently thriving, some northern Fennoscandian populations appear to be vulnerable to further loss of genetic variability and are likely to have limited capacity to adapt if selection pressures change.Peer reviewe

Vascular adhesion protein-1 is actively involved in the development of inflammatory lesions in rat models of multiple sclerosis

Background: Vascular adhesion protein-1 (VAP-1) is an inflammation-inducible endothelial cell molecule and primary amine oxidase that mediates leukocyte entry to sites of inflammation. However, there is limited knowledge of the inflammation-related expression of VAP-1 in the central nervous system (CNS). Therefore, we investigated the expression of VAP-1 within the CNS vasculature in two focal rat models of experimental autoimmune encephalomyelitis (EAE) mimicking multiple sclerosis (MS).Methods: EAE was induced either with Bacillus Calmette-Guerin, resulting in a delayed-type hypersensitivity-like pathogenesis (fDTH-EAE), or with myelin oligodendrocyte glycoprotein (fMOG-EAE). A subgroup of fMOG-EAE rats were treated daily with a selective VAP-1 inhibitor (LJP1586; 5 mg/kg). On 3 and 14 days after lesion activation, rat brains were assessed using magnetic resonance imaging (MRI), and ex vivo autoradiography was conducted to evaluate the binding of Gallium-68-labelled VAP-1 ligand. Histology and immunohistochemistry (OX-42, VAP-1, intercellular adhesion protein-1 [ICAM-1], P-selectin) supported the ex vivo autoradiography.Results: EAE lesions showed MRI-detectable signal changes and binding of the VAP-1-targeting radiotracer in both rat models. Some of the VAP-1 positive vessels showed morphological features typical for high endothelial-like venules at sites of inflammation. Inhibition of VAP-1 activity with small molecule inhibitor, LJP1586, decreased lymphocyte density in the acute inflammatory phase of fMOG-EAE lesions (day 3, P = 0.026 vs. untreated), but not in the remission phase (day 14, P = 0.70 vs. untreated), and had no effect on the amount of OX-42-positive cells in either phase. LJP1586 treatment reduced VAP-1 and ICAM-1 expression in the acute inflammatory phase, whereas P-selectin remained not detectable at all studied stages of the disease.Conclusions: Our results revealed that VAP-1 is expressed and functionally active in vasculature within the induced focal EAE lesions during the acute phase of inflammation and remains expressed after the acute inflammation has subsided. The study indicates that VAP-1 is actively involved in the development of inflammatory CNS lesions. During this process, the endothelial cell lesion-related vasculature seem to undergo a structural transformation from regular flat-walled endothelium to HEV-like endothelium

Action of dexmedetomidine on the substantia gelatinosa neurons of the rat spinal cord

Dexmedetomidine is a highly specific, potent and selective α2-adrenoceptor agonist. Although intrathecal and epidural administration of dexmedetomidine has been found to produce analgesia, whether this analgesia results from an effect on spinal cord substantia gelatinosa (SG) neurons remains unclear. Here, we investigated the effects of dexmedetomidine on postsynaptic transmission in SG neurons of rat spinal cord slices using the whole-cell patch-clamp technique. In 92% of the SG neurons examined (n= 84), bath-applied dexmedetomidine induced outward currents at −70 mV in a concentration-dependent manner, with the value of effective concentration producing a half-maximal response (0.62 μm). The outward currents induced by dexmedetomidine were suppressed by the α2-adrenoceptor antagonist yohimbine, but not by prazosin, an α1-, α2B- and α2C-adrenoceptor antagonist. Moreover, the dexmedetomidine-induced currents were partially suppressed by the α2C-adrenoceptor antagonist JP-1302, while simultaneous application of JP-1302 and the α2A-adrenoceptor antagonist BRL44408 abolished the current completely. The action of dexmedetomidine was mimicked by the α2A-adrenoceptor agonist oxymetazoline. Plots of the current–voltage relationship revealed a reversal potential at around −86 mV. Dexmedetomidine-induced currents were blocked by the addition of GDP-β-S [guanosine-5′-O-(2-thiodiphosphate)] or Cs+ to the pipette solution. These findings suggest that dexmedetomidine hyperpolarizes the membrane potentials of SG neurons by G-protein-mediated activation of K+ channels through α2A- and α2C-adrenoceptors. This action of dexmedetomidine might contribute, at least in part, to its antinociceptive action in the spinal cord

Quantification of the purinergic P2X(7) receptor with [C-11]SMW139 improves through correction for brain-penetrating radiometabolites

The membrane-based purinergic 7 receptor (P2X(7)R) is expressed on activated microglia and the target of the radioligand [C-11]SMW139 for in vivo assessment of neuroinflammation. This study investigated the contribution of radiolabelled metabolites which potentially affect its quantification. Ex vivo high-performance liquid chromatography with a radio detector (radioHPLC) was used to evaluate the parent and radiometabolite fractions of [C-11]SMW139 in the brain and plasma of eleven mice. Twelve healthy humans underwent 90-min [C-11]SMW139 brain PET with arterial blood sampling and radiometabolite analysis. The volume of distribution was estimated by using one- and two- tissue compartment (TCM) modeling with single (V-T) and dual (V-Tp) input functions. RadioHPLC showed three major groups of radiometabolite peaks with increasing concentrations in the plasma of all mice and humans. Two radiometabolite peaks were also visible in mice brain homogenates and therefore considered for dual input modeling in humans. 2TCM with single input function provided V-T estimates with a wide range (0.10-10.74) and high coefficient of variation (COV: 159.9%), whereas dual input function model showed a narrow range of V-Tp estimates (0.04-0.24; COV: 33.3%). In conclusion, compartment modeling with correction for brain-penetrant radiometabolites improves the in vivo quantification of [C-11]SMW139 binding to P2X(7)R in the human brain.</p

A review of the impacts of degradation threats on soil properties in the UK

National governments are becoming increasingly aware of the importance of their soil resources and are shaping strategies accordingly. Implicit in any such strategy is that degradation threats and their potential effect on important soil properties and functions are defined and understood. In this paper, we aimed to review the principal degradation threats on important soil properties in the UK, seeking quantitative data where possible. Soil erosion results in the removal of important topsoil and, with it, nutrients, C and porosity. A decline in soil organic matter principally affects soil biological and microbiological properties, but also impacts on soil physical properties because of the link with soil structure. Soil contamination affects soil chemical properties, affecting nutrient availability and degrading microbial properties, whilst soil compaction degrades the soil pore network. Soil sealing removes the link between the soil and most of the ‘spheres’, significantly affecting hydrological and microbial functions, and soils on re-developed brownfield sites are typically degraded in most soil properties. Having synthesized the literature on the impact on soil properties, we discuss potential subsequent impacts on the important soil functions, including food and fibre production, storage of water and C, support for biodiversity, and protection of cultural and archaeological heritage. Looking forward, we suggest a twin approach of field-based monitoring supported by controlled laboratory experimentation to improve our mechanistic understanding of soils. This would enable us to better predict future impacts of degradation processes, including climate change, on soil properties and functions so that we may manage soil resources sustainably

Effects of age, BMI and sex on the glial cell marker TSPO - a multicentre [C-11]PBR28 HRRT PET study

Purpose The purpose of this study was to investigate the effects of ageing, sex and body mass index (BMI) on translocator protein (TSPO) availability in healthy subjects using positron emission tomography (PET) and the radioligand [C-11]PBR28. Methods [C-11]PBR28 data from 140 healthy volunteers (72 males and 68 females; N = 78 with HAB and N = 62 MAB genotype; age range 19-80 years; BMI range 17.6-36.9) were acquired with High Resolution Research Tomograph at three centres: Karolinska Institutet (N = 53), Turku PET centre (N = 62) and Yale University PET Center (N = 25). The total volume of distribution (V-T) was estimated in global grey matter, frontal, temporal, occipital and parietal cortices, hippocampus and thalamus using multilinear analysis 1. The effects of age, BMI and sex on TSPO availability were investigated using linear mixed effects model, with TSPO genotype and PET centre specified as random intercepts. Results There were significant positive correlations between age and V-T in the frontal and temporal cortex. BMI showed a significant negative correlation with V-T in all regions. Additionally, significant differences between males and females were observed in all regions, with females showing higher V-T. A subgroup analysis revealed a positive correlation between V-T and age in all regions in male subjects, whereas age showed no effect on TSPO levels in female subjects. Conclusion These findings provide evidence that individual biological properties may contribute significantly to the high variation shown in TSPO binding estimates, and suggest that age, BMI and sex can be confounding factors in clinical studies

Among-individual paternity distance and extra-group paternity

This file contains data used for the individual-level analyses of paternity distance (PDi) and extra-group paternity. Data were collected as part of the long-term mark-recapture study of badgers at Woodchester Park (UK). It includes unique identifiers for each badger (ID) as well as their assigned father (Sire ID) and mother (Dam ID), the natal group ID of each badger (Cub_SocG) and its father (Sire_SocG) as well as the distance from cub to paternal social group (zero if same group, measured in meters from social group main sett to social group main sett), parental ages (Dam and Sire Age) and weights (Dam and Sire weight) in kilos, and size (number of adults) and sex ratio (proprtion male) of badgers natal group (Cub_SocG size, sex ratio) and that of their father's social group ( Sire_SocG Size, Sex Ratio)

Intracranial aneurysms in three patients with disseminated Lyme borreliosis: cause or chance association?

METHODS—Three patients with Borrelia burgdorferi infection and intracranial aneurysms are described.
RESULTS—All three patients had neurological symptoms. Perivascular and vasculitic lymphocytic inflammation were detected in the brain biopsy specimen of one patient. The aneurysm was located in the internal carotid arteries in two patients and in the basilar artery in one patient. The aneurysm ruptured in two patients.
CONCLUSIONS—Cerebral lymphocytic vasculitis and intracranial aneurysms may be associated with B burgdorferi infection. It is suggested that inflammatory changes caused by B burgdorferi in vessel walls may be a pathogenetic mechanism for the formation of aneurysms.