No description available.

No description available.

No description available.

No description available.

No description available.

Selected ion flow tube mass spectroscopy (SIFT-MS) is an analytical method for the investigation of volatile organic compounds (VOCs). It produces mass to charge (m/z) ratio ion counts with a range of 10-200 m/z. Current data analysis involves sifting through the spectra files one at a time looking for peaks of interest. This is time consuming and requires expert knowledge. This thesis proposes, implements and demonstrates a novel approach to the analysis of SIFT-MS data using multivariate techniques similar to those employed to analyse electronic nose and gas chromatography mass spectroscopy (GCMS) data. The methodology was developed using a set of samples created in the laboratory that belonged to two groups which contained different VOCs found in biological samples. The methodology requires the removal of the m/z peaks associated with the precursors, then principal component analysis (PCA) and partial least squares discriminant analysis (PLSDA) methods were evaluated for biomarker discovery and sample classification. Both methods produced excellent results, identifying the volatiles in the mixtures and being able to classify samples with 100% accuracy. This methodology was then tested using a variety of samples. Ammonia was found as a possible marker for bovine TB (Mycobacterium bovis) infection using serum samples taken from wild badgers. Discrimination results of an accuracy of 67%±6% were acquired. The number of sample needed to build the best performing model from this dataset was empirically shown to be 120. It was shown to be effective for the discrimination of serum samples from cattle taken before and after introduction of bovine TB (Mycobacterium bovis) bacteria in a clinical trial (accuracy of 85% achieved). A similar dataset pertaining to infection by Mannheimia haemolytica failed to produce models that performed as well as the others - this is suspect to be due to a poor experimental design. Finally, discrimination accuracies of 88% for urine samples collected from cattle from herds infected with Mycobacterium paratuberculosis and 90% for urine samples collected in the same bovine TB trial as above were achieved. The novel multivariate approach to SIFT-MS data analysis has been shown to be effective with a number of datasets but it is sensitive to the experimental design. Recommendation for the consideration required for analysis using this method have been made.

This thesis is about veterinary expertise, with a focus on the farm/large animal sector. It explores how vets and the profession express expertise beyond medical knowledges and technical competencies. Drawing from rich, detailed ethnographic case studies of UK vets working in the rural sector in a variety of roles (e.g. private practice, government, education) the thesis offers new understandings of professional expertise and Aesculapian authority – the most powerful authority awarded by society to those who heal. The main argument is that veterinary expertise cannot be easily defined or compartmentalised as it is fluid and at times contested and means different things to different people at different times and places. Furthermore, in analysing veterinary expertise I found it necessary to understand the relationship between veterinarians‟ notions of general practice and specialisation. Through historical and empirical evidence my research has found two main reasons to explain why veterinary specialisation appears to be underdeveloped. First, at the professional level, veterinarians strongly assert the primacy of general practice and contest the notion of veterinary specialisation as divisive. Second, at the individual level, many veterinarians work in very defined areas of practice that may be considered to be specialised. Yet they maintain they are still general practitioners. In light of these contradictions my thesis suggests that veterinarians should be conceptualised as „poly-specialists‟. Theoretically the thesis develops the notion of veterinary Aesculapian authority and Goffman‟s „dramaturgical perspective‟ to understand the veterinary „performance‟. The thesis argues that the authority and power of the individual and profession is one aspect of veterinary expertise but also the ways in which vets interact in different physical settings (the performance in front and back stage settings) is important. Exploring the veterinary performance reveals the fluid nature of their expertise as it varies according to the physical setting, is related to personal characteristics and the way they construct, maintain and express their Aesculapian authority.

No description available.

No description available.

Spironucleus species are anaerobic, flagellated protozoa, which can be either parasitic or commensal and are related to the ubiquitous human parasite, Giardia intestinalis. These parasites are responsible for devastating outbreaks of systemic infections in a wide range of food and ornamental fish and thus represent a significant problem in aquaculture. Despite the detrimental impact of Spironucleus species on an industry of growing importance, they have been little investigated, and information on their metabolism, host-parasite interactions, geographical range, pathogenesis and chemotherapy is scarce. A better understanding of the biology of these parasites is therefore essential for effective disease management. This thesis aimed at advancing the knowledge of Spironucleus parasites, by providing novel information on their growth, metabolism, ultrastructure and treatment. Spironucleus vortens, a parasite of cichlids, was used as a model organism in these investigations. Following optimization of in vitro growth conditions, S. vortens proved to be a non-fastidious organism, and grew to high densities (2.6 x 106 cells, ml"1) with a very short doubling time (1.79 h), but demonstrated an unusual biphasic pattern of growth. Despite being categorized as anaerobic, the organism exhibited both an unusually high tolerance and affinity for O2. Garlic and allium-derived thiosulfinates, which are know for their powerful, broad spectrum antimicrobial properties, had a dose-dependant inhibitory effect on S. vortens, albeit at doses higher than that required for the inhibition of most microorganisms investigated so far. Metabolic investigations demonstrated that the organism could use glucose, but that the compound was not its preferred substrate. The organism was also found to contain large pools of endogenous substrates, exhibited high proteolytic activity and was capable of rapid phagocytosis of non-soluble particles. Although Spironucleus species were described as lacking hydrogenosomes, S. vortens produced H2 at a very high rate, and ultrastructural and enzymatic studies revealed that despite previous reports, the organism possessed hydrogenosome-like, redox-active organelles. Besides hydrogenosomes, mitosome-like organelles were also detected. Such combination is currently unique in the eukaryotic kingdom and has important implications for current theories of organelles and eukaryotic evolution.