Animal & Avian Sciences Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2741
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Item COMPARATIVE STUDY OF LIPOPROTEIN METABOLISM IN MAREK'S DISEASE SUSCEPTIBLE AND RESISTANT LINES(2010) Yuan, Ping; Song, Jiuzhou; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Marek's disease virus (MDV) infection causes atherosclerosis, and prior vaccination prevented the development of this disease. Two main strategies to resist Marek's disease (MD) have been demonstrated: vaccination and genetic resistance. However, little is known about the role of genetic resistance in the progression of MDV induced atherosclerosis. Atherosclerosis is primarily associated with lipoprotein metabolism. The purpose of this study was to investigate whether lipoprotein metabolisms are different in distinct MD susceptible and resistant chicken lines. Here, we studied different backgrounds of lipoprotein metabolism in the two lines and the changes of lipoprotein levels in response to MDV infection. The results showed that during chicken growth, the increase in total cholesterol was mostly due to the increasing (LDL+VLDL) in MD susceptible line, whereas it was mainly due to the elevating HDL in MD resistant line. These results suggested that different lipoprotein metabolisms exist in MD susceptible and resistant lines.Item Proteomic Profiling and Label-Free Quantification of Bovine Milk Proteins during Experimentally Induced Escherichia coli Mastitis(2009) Boehmer, Jamie Layne; Peters, Robert R; Bannerman, Douglas D; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Coliform mastitis has been a primary focus of dairy cattle disease research due to staggering affiliated losses, severe systemic complications arising from host inflammatory response to lipopolysaccharide, and the poor response of coliform pathogens to antimicrobials. Reliable biomarkers are needed to evaluate the efficacy of adjunctive therapies for the treatment of inflammation associated with coliform mastitis, and to aid in the approval of new veterinary drugs. The aims of the current analyses were to utilize proteomic methodologies to evaluate protein expression in whey from cows with experimentally induced coliform mastitis, and to employ label-free quantification strategies to estimate changes in relative abundance of proteins identified in milk over the course of clinical infection. Two-dimensional gel electrophoresis followed by matrix-assisted laser desorption/ionization time-of-flight (MALDI- TOF) mass spectrometry (MS) resulted in the identification of complement factors, antimicrobial proteins, and acute phase proteins in mastitic milk. Analysis using liquid chromatography (LC) inline with electrospray ionization - quadrupole TOF tandem mass spectrometry (MS/MS) resulted primarily in the identification of abundant whey and casein proteins, and the transient detection of proteins related to host response. Nano-LC- nanospray-MS/MS using a linear ion trap, however, led to the robust discovery of over fifty inflammatory proteins in whey from mastitic milk, including the novel markers kininogen-2 and inter-alpha trypsin inhibitor heavy chain-4. Normalized spectral counts were compared to enzyme-linked immunosorbant assay (ELISA) for select proteins to assess the accuracy of the spectral count data. Similar expression patterns were detected using spectral counts and ELISA. Results indicate that proteomic methodologies can detect biomarkers of coliform mastitis in bovine milk during clinical infections, and that spectral counts are a viable means of evaluating relative changes in protein biomarkers of mastitis, including those for which no antibody currently exists.Item MILK AND BLOOD CONCENTRATIONS OF LIPOPOLYSACCHARIDE-BINDING PROTEIN IN COWS WITH NATURALLY-OCCURRING SUBCLINICAL AND CLINICAL MASTITIS(2008-08-22) ZENG, RONGYU; Bequette, Brian J; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The objective of this thesis was to evaluate the blood and milk concentrations of lipopolysaccharide-binding protein (LBP) from cows with naturally-occurring mastitis as biomarkers of this disease. Milk and blood samples were collected from 101 clinically healthy dairy cows and 17 dairy cows with clinical mastitis. The concentrations of LBP, haptoglobin and serum amyloid A (SAA) were determined in these samples by enzyme-linked immunosorbent assay. Both LBP and haptoglobin concentrations were higher in the milk and blood of quarters and cows with clinical mastitis respectively than in those that were healthy. Whereas haptoglobin concentrations differed between uninfected and subclinically-infected quarters, LBP concentrations only differed between them when milk somatic cell counts were low. Unlike haptoglobin and SAA, blood concentrations of LBP in cows with a subclinical intramammary infection were not significant from those of cows with all healthy quarters. Thus, haptoglobin may be a preferred biomarker of subclinical intramammary infection.Item EPIDEMIOLOGIC ANALYSIS OF RISK FACTORS FOR LOCAL DISAPPEARANCES OF NATIVE RANID FROGS IN ARIZONA(2005-08-11) Witte, Carmel Lee; Kane, Andrew S.; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study used epidemiologic case-control methodology to examine habitat and environmental factors contributing to amphibian declines in Arizona. Risk factors were compared between sites where frogs disappeared (cases) and persisted (controls) using univariate and multivariable logistic regression analyses. Thirty-six percent (117/324) of all sites became cases during the study period. Elevation, non-native predators, hydrologic characteristics, aspect, and effects of nearby sites were significantly associated with frog persistence or disappearance. In the final multivariable model, risk for disappearance increased with increasing elevation (OR=2.7 for every 500 meters, P<0.01). Sites where disappearances occurred were 4.3 times more likely to have other nearby sites that also experienced disappearances (P<0.01), while having an extant population nearby decreased risk of disappearance by 85% (OR=0.15, P<0.01). Sites experiencing disappearances were 2.6 times more likely to have crayfish than control sites (P=0.04). Identification of risk factors associated with frog disappearances will guide future research and conservation efforts.