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Theses and Dissertations

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Browsing Theses and Dissertations by Subject "animal diseases"

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    Immunoproteomic identification of bovine pericardium xenoantigens
    (Colorado State University. Libraries, 2008) Griffiths, Leigh G., author; Orton, E. Christopher, advisor; Reardon, Kenneth F., advisor
    Bovine pericardium (BP) is an important biomaterial used in the production of gluteraldehyde-fixed heart valves and tissue engineering applications. The ability to perform proteomic analysis on BP is potentially useful for several reasons including investigation of immune rejection after implantation. The importance of humoral and cell mediated rejection responses towards such xenogeneic tissues are becoming increasingly apparent. I have applied a novel immunoproteomic approach to survey the antigenic determinants of BP. Proteomic analysis of fibrous tissues like BP is challenging due to their relative low cellularity and abundance of extracellular matrix. A variety of methods for tissue homogenization, protein extraction, and fractionation were investigated with the aim of producing high quality 2-DE gels for both water- and lipid-soluble BP proteins. MALDI-TOF/TOF MS protein identifications were performed to confirm bovine origin and appropriate subcellular fractionation of resolved proteins. Sixteen unique predominantly cytoplasmic bovine proteins were identified from the water-soluble gels. Twenty-two unique predominantly membrane bovine proteins were identified from the lipid-soluble gels. These results demonstrate that the final 2-DE protocol produced high quality proteomic data from BP for both cytoplasmic and membrane proteins. Duplicate 2-DE gels were used to generate western blots from both water- and lipid-soluble gels. Western blots were probed with pre- and post-exposure anti-BP rabbit serum, with detection of immune complexes limited to the IgG subtype. Western blots were compared to duplicate 2-DE gels and spots matched using Delta 2D image analysis software. Protein identifications of matched spots were performed using either MALDI-TOF/TOF MS or ESI MS/MS. This approach identified 31 putative antigens, capable of stimulating an IgG humoral rejection response. To the best of my knowledge, this study was the first to apply an immunoproteomic approach for identification of antigenic targets in xenotransplanted tissues. The results provide important information for understanding and possibly mitigating the immune response to fixed and unfixed BP xenografts.
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    Investigation into disease events at the wildlife/livestock interface: lessons learned from bovine viral diarrhea virus in Colorado cervids
    (Colorado State University. Libraries, 2009) Duncan, Colleen, author; Salman, Mo, advisor; VanCampen, Hana, advisor
    Infectious agents may be transmitted between wild and domestic animals; these so called 'interface diseases' can have significant economic consequences. As such, effective tools and techniques with which to study disease in free ranging, wild animals is essential. Principles of wildlife disease surveillance were reviewed and it was concluded that while wildlife disease research may require unique logistical adaptations; basic principles of surveillance remain the same. A review of wildlife data sources utilized for surveillance suggests that information collected, and shared, is dependent on the group involved and that there are opportunities to improve the type and quality of material available. Bovine viral diarrhea virus (BVDV) is an important virus of domestic cattle that has recently been identified in wild ruminants worldwide. To investigate the presence, prevalence, distribution and significance of BVDV in wild cervids of Colorado a series of projects were conducted. Persistently infected (PI) deer were studied post mortem; immunohistochemical and molecular techniques used to look for viral antigen in deer tissue were found to be effective supporting the use of these tests in further studies. The prevalence and distribution of PI cervids in the state was evaluated using an opportunistic sampling technique; the prevalence is extremely low, but naturally occurring infection is present within Colorado. The cost associated with testing animals for an uncommon disease may be very high; techniques like pooling samples can help to keep costs down during such investigations. The sensitivity and specificity of RT-PCR on pooled samples was investigated in an experimental study and revealed that supernatant from a single positive deer skin sample may be diluted up to 10,000 times and still be detected. Another technique to focus research efforts on high risk areas is the use of simulation modeling. A stochastic risk assessment model was developed to identify regions in Colorado where PI cattle were likely to be born following exposure to a PI deer. Results of the model were consistent with both the cross-sectional survey for PI cervids and other reports on BVDV in wildlife of Colorado.
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    Peri-slaughter ecology of Escherichia coli O157 and Salmonella enterica in feedlot beef cattle
    (Colorado State University. Libraries, 2008) Dewell, Grant Alan, author; Salman, Mo, advisor
    Risk factors for prevalence of E. coli O157 prior to slaughter and the genotypic relationship between feedlot and slaughter isolates were investigated. The odds of E. coli O157 positive fecal samples from cattle fed brewers grains were 6 times that for cattle not fed brewers grains. The odds of E. coli O157 positive fecal samples from cattle from Central Nebraska was 9 times that for cattle from Eastern Colorado. Within the sampled pens, 64% of the hide samples at the abattoir corresponded to a feedlot isolate. For carcass samples, 59% of isolates had a corresponding feedlot isolate. Transportation of cattle from the feedlot to the slaughter plant could influence hide contamination of Escherichia coli O157 or Salmonella enterica. Cattle held in E. coli O157 positive lairage pens had eight times greater relative risk of having E. coli O157 positive hide samples compared to cattle held in culture-negative pens. Cattle that were held in lairage pens contaminated with feces had three times greater relative risk for E. coli O157 positive hide samples and twice the relative risk for S. enterica positive hide samples compared to cattle held in clean pens. Cattle that were transported for long distances (> 160.9 km) had twice the relative risk of having E. coli O157 positive hide samples and twice the relative risk of having S. enterica positive hide samples compared to cattle transported shorter distances. Cattle with positive Salmonella enterica hide samples at the feedlot had almost twice the relative risk of having S. enterica positive hide samples compared to cattle without S. enterica positive feedlot hide samples. Cattle transported in trailers with positive S. enterica samples had over twice the relative risk of having S. enterica positive hide samples compared to cattle transported in culture negative trailers. Cattle held off feed longer than 18 hours before loading had a greater relative risk of having S. enterica positive hide samples compared to cattle held off feed for shorter times. Cattle that were agitated during loading had twice the relative risk of having S. enterica positive hide samples compared to cattle that were calm.