Thesis (Ed. D.)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: Betsy Palmer. Includes bibliographical references (leaves 111-118).

Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on June 26, 2009). Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 142-144.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 154-156).

Tesis-Universidad de Navarra. / Bibliography: p. 171-176.

4 pp. / Vaccinating for clostridial diseases is an important part of a ranch health program. These infections can have significant economic impacts on the ranch due to animal losses. There are several diseases caused by different organisms from the genus Clostridia, and most of these are preventable with a sound vaccination program. Many of these infections can progress very rapidly; animals that were healthy yesterday are simply found dead with no observed signs of sickness. In most cases treatment is difficult or impossible, therefore we rely on vaccination to prevent infection. The most common organisms included in a 7-way or 8-way clostridial vaccine are discussed below. By understanding how these diseases occur, how quickly they can progress, and which animals are at risk you will have a chance to improve your herd health and prevent the potential economic losses that come with a clostridial disease outbreak.

Newly developed hydrogels, produced by cross linking purified poly ($\gamma$-glutamic acid) ($\gamma$PGA) with dihaloalkane compounds were utilized for slow-release of porcine somatotropin (pST). The polymer was produced by fermentation of Bacillus licheniformis. It was found that the rate of the crosslinking reaction and hydrogel yield were affected by several parameters, such as temperature, initial polymer and base concentrations as well as the type of crosslinkers. Reaction occurred rapidly at a polymer concentration of 40-80 mg/ml and temperature of 60-80$\sp\circ$C without hydrolysis of newly formed networks and polymer backbone. The optimal concentration for the base (NaHCO$\sb3$) was 1-2 mole per mole of carboxylic residues. Analysis of the hydrolysis of the hydrogels as a function of pH indicated that the hydrolysis occurred very slowly at neutral pH, but rapidly in both acidic and alkaline solution. The ester bonds were more sensitive to hydrolysis than the peptide bonds. The biodegradability of the hydrogels and polymer was further examined through enzymatic degradation by three enzymes (Cathepsin B, Pronase E and Trypsin), which were able to gradually cleave both ester and peptide bonds. Swelling of the hydrogel showed dramatic changes when experimental conditions such as the molecular weight of $\gamma$-PGA, nature of the crosslinkers and solutions used for swelling (ionic strength, organic solvent) were varied. The swelling degree was positively correlated with initial molecular weight of $\gamma$-PGA, but inversely correlated with the chain length of the crosslinkers and the crosslinking degree. Increasing the organic solvent or ionic concentration in solutions decreased the gel swelling, which was in agreement with general reports in literature. Porcine somatotropin (pST) is a very unstable hormone in aqueous environment. It was found in this research that the peptide underwent aggregation and decomposition at extreme pH, but was relatively stable in neutral pH. Aggregation was positively correlated with pST and ionic concentrations. The hormone monomer was stabilized to a certain degree in glucose solutions and at low concentration of urea. A quantitative ELISA method was established using anti-pST monoclonal and multiclonal antibodies. The method was simple and specific. The release profiles of $\gamma$-PGA based hydrogels for p-nitroaniline and BSA were studied in vitro. Hydrogels formed with longer chain crosslinkers released materials much slower than shorter chain dihaloalkanes, but unevenly release was observed for macromolecules. The hydrogels formed by dihalopentane was applied for slow-release of pST in vitro and in vivo. Although the aggregation and decomposition of pST were expected in the system, the hydrogel was able to release the hormone for a period of 20-30 days in vitro and in an in vivo rat experiment. In live piglets, the release system increased growth rate by 17% during 8-week experiment. This research demonstrated the potential application of $\gamma$PGA based hydrogels in slow-release systems for bioactive materials, especially macromolecules, such as peptides and proteins.

An efficient system for genetic modification and large scale cloning of cattle is of importance for agriculture, biotechnology and human medicine. Two approaches were investigated here to produce a transgenic bovine. First, the use of embryonic stem (ES) cells in production of chimeras and second, the use of nuclear transfer procedures using genetically modified somatic cells as nuclear donors. Embryonic stem (ES) cells could be useful for generating transgenic cattle or cells for xenotransplantation. The in vitro production of tissue for xenotransplantation requires the development of an unlimited source of pluripotent cells. Furthermore, these cells should be capable of being genetically modified to aid in directing differentiation, reducing graft rejection, improving graft survival and for producing therapeutic proteins in vivo. A novel method was developed, using nuclear transplantation, to produce transgenic ES cells from fetal bovine fibroblasts. These cells, when reintroduced into preimplantation embryos, were able to differentiate into derivatives from the three embryonic germ layers; ectoderm, mesoderm and endoderm in adult animals. Six out of seven calves born were found to be chimeric for at least one tissue (86%). This work demonstrates that somatic cells can be genetically modified and then dedifferentiated by nuclear transfer into ES-like cells, opening the possibility of using them in differentiation studies and human cell therapy. In order to produce a whole transgenic bovine in one generation, fetal fibroblasts were genetically modified with a marker gene, a clonal line was selected and the cells were fused to enucleated mature oocytes. Out of 130 embryos transferred to 53 recipient cows, seven healthy, identical, transgenic calves were generated. Furthermore, the lifespan of near senescent fibroblasts could be extended by nuclear transfer, as indicated by population doublings in fibroblast lines derived from a 40 day fetal clone. With the ability to extend the lifespan of these primary cultured cells, this system should be very useful for inducing complex genetic modifications in cattle.

Human, antigen-specific polyclonal antibodies are in high demand for therapeutic and research applications. However, the supply of these antibodies currently comes from only human donors and cannot satisfy the demand. The application of pathogen-specific human polyclonal antibodies is limited because there are severe restrictions on the kinds of antigens and the immunization protocols that can be used in humans. In the attempt to resolve the issue of the supply of antigen-specific, human polyclonal antibodies, transgenic for human Ig (hIg) animals were created. The most sufficient and promising model was the human artificial chromosome (HAC) transgenic animal. This model was successful due to the most efficient transferring vector CS20, comprising the entire unrearranged human heavy (1.5MB) and lambda locus (1 MB). In order to produce a large quantity of polyclonal hIg, cloned HAC transgenic cattle were created. Highly human-specific and bovine non-cross reactive, polyclonal bovine anti-human antibody and sensitive solid phase ELISA were created to determine, quantify, and characterize hIg in the sera of HAC transgenic cattle. Using the assay, that have been developed in this study; it was found that the majority of the HAC cattle produce hIg. It was also found that both heavy and light chains of hIg are produced by HAC bovines. The heavy chain of hIg undergoes class switching to the IgG and its half-life is 30 days, which is longer than hIgG in humans (21 days) or bovine IgG in bovines (19 days). Highly human-specific and bovine non-cross reactive monoclonal antibodies for the characterization of hIg produced by HAC cattle were created to recognize hIg heavy chain classes/subclasses and light chains. Analysis of the human V lambda genes sequences derived from HAC transgenic cattle demonstrated that human genes undergo extensive rearrangement and somatic hypermutation following normal Ig patterns. This study has demonstrated that hIg produced by HAC cattle diversifies according to normal Ig patterns and undergoes class switching to IgG. The half-life of hIgG is sufficiently long for protection from pathogens of the homozygous Ig deficient HAC cattle, and for harvesting of human IgG. HAC transgenic cattle can be potential donors of human polyclonal Ig.