Porcine Reproductive and Respiratory Syndrome virus (PRRSV) causes the disease - Porcine Reproductive and Respiratory Syndrome (PRRS) which is one of the most economically important diseases for pig farmers. Since it was discovered in the United States and Europe, it has quickly affected the swine industry all over the world. Studying and controlling PRRSV has become an important issue in swine industry and scientific community, and has raised the concerns of governments like US and China. By using different bioinformatics and phylogenetics tools, scientists could understand the epidemiology and evolution of PRRSV from genomic data. However, a well-designed database for PRRSV sequence and relevant meta-information are generally required for the tools to produce insightful results. Therefore, I would like to introduce an easily accessible web platform for PRRSV analysis - PRRSV-Webtool. The core component of PRRSV-Webtool is phylogenetic reconstruction. Instead of using traditional phylogenetic reconstruction, a new method of reconstruction was introduced - Reconstruction by Addition of Taxon (RAT). RAT could build a phylogenetic tree from known existing phylogeny. Simulation tests were performed to evaluate the accuracies of RAT using PRRSV dataset. The percentages of correct branch reconstruction are 73.81% for type 1 PRRSV dataset and 80.68% for type 2 PRRSV dataset. Another important function of PRRSV-Webtool is genotyping. RAT could correctly identify the genotype of all sequences in the testing datasets. PRRSV-Webtool combined three main components: database, phylogenetic tool and World Wide Web. By using PRRSV-Webtool, the users can study their own PRRSV genome data easily via the web browser. Tools in PRRSV-Webtool can allow users to know more about their PRRSV isolates related to other field samples. With our PRRSV-Webtool, scientists and veterinaries can help to improve their understanding of PRRSV and help to control the virus by accelerating the process of virus surveillance and field sampling. / published_or_final_version / Biological Sciences / Master / Master of Philosophy

Porcine Periweaning Failure-to-Thrive syndrome (PFTS) is a clinical syndrome of newly weaned pigs with unknown etiology and characterized by anorexia, lethargy and progressive debilitation. The hypothesis of this thesis is that PFTS is an infectious disease. Investigation in an index farm affected by PFTS from Saskatchewan Canada ruled out most common swine pathogens as the etiology and identified several lesions that were consistent across many cases. A larger study including multiple farms in North America was then undertaken. A total of 8 farms were investigated, within which 5 met the clinical definition of PFTS. Gross and histological examinations were performed on 8 case and 4 control pigs on each farm. Detection of relevant porcine pathogens, complete blood count, serum chemistry, and serum cytokine analysis were performed on each pig. Thymic atrophy, superficial gastritis and small intestinal villous atrophy were significantly more prevalent in case pigs compared to control pigs. All case pigs had at least two of these three lesions. All case and control pigs were negative for porcine reproductive and respiratory syndrome virus, swine influenza virus and were free of porcine circovirus associated diseases. Although several pathogens, such as porcine cytomegalovirus, haemagglutinating encephalomyelitis virus, porcine enteric calicivirus, group A rotavirus, enteroviruses and Cystoisospora suis were detected in some of the case and control pigs, none were associated with clinical status. Clinical pathology findings of case pigs was consistent with anorexia and dehydration, such as increases in haematocrit, blood urea, serum bilirubin, albumin, beta-hydroxybutyrate and decreases in blood glucose, calcium and phosphorous. Case pigs had similar levels to IL1-β than control pigs, which suggested that PFTS was not a result of excessive cytokines. In subsequent experiments, a snatched-farrowed porcine-colostrum-deprived (SF-pCD) pig model was developed and tissue homogenates were used to inoculate SF-pCD pigs in an attempt to reproduce the clinical signs of PFTS. The SF-pCD pigs were immunologically characterized and shown to be suitable for inoculation studies. However, inoculation of tissue homogenate from PFTS pigs failed to reproduce the clinical signs of PFTS in SF-pCD pigs. All together, PFTS is a clinical syndrome with consistent pathological and serum analytical changes among affected pigs. Despite the efforts of this research to establish an infectious etiology, there is a lack of evidence that PFTS is an infectious disease.

No description available.

No description available.

Graduation date: 1992

Islet transplantation is a more physiological way to treat type 1 diabetes. However, shortage of donor tissue and chronic administration of immune suppressive drugs has limited the widespread application of this therapy for all patients with type 1 diabetes, particularly children suffering from this disease. Xenogeneic islet transplantation particularly neonatal porcine islets (NPI) holds promise for clinical transplantation because of the potentially unlimited supply of islets. New evidence suggests that monoclonal antibodies (mAbs) specific for immune cell surface molecules could be employed in the prevention of islet graft rejection as well as induction of immunological tolerance to the transplanted grafts without the need for continuous administration of harmful immune suppressive drugs. It was shown by our group that short-term administrations of a combination of anti-LFA-1 and anti-CD154 mAbs which targets both adhesion and costimulatory pathways of T cell activation, is highly effective in preventing NPI xenograft rejection. In this thesis, we determined whether short-term administration of a combination of anti-LFA-1 and anti-CD154 mAbs could induce tolerance to NPI xenografts. Our data show that this combination of mAbs can induce dominant, species and tissue specific tolerance to NPI xenografts which is mediated by regulatory T cells in non-autoimmune prone B6 mice. We also found that T cell subsets such as CD4+ and CD8+ T cells as well as antigen presenting cells (APC) play an important role in the induction and maintenance of tolerance to NPI xenografts. In addition we found that PD-1/PDL interaction is important for induction and maintenance of tolerance to NPI xenografts. Finally, we found that this combined mAb therapy was effective in preventing NPI xenografts rejection in autoimmune prone NOD mice when it was combined with anti-CD4 mAb. It is may hope that the research presented in this thesis will provide insight into the nature of the immune responses to xenogeneic islet transplantation in humans and aid in the development of effective, tolerance inducing therapies, so that patients with T1DM will once again know a life free from their disease. / Experimental Surgery

Bibliography: leaves 112-140. / xi, 141, [39] leaves, [8] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aims of this thesis are to determine the initial cleavage sites of purified pepsin in long-R3-IGF-I and assess whether the resulting cleavages affect biological activity, to design and produce analogues of long-R3-IGF-I which contain amino acid substitutions, to characterise the resulting analogues for pepsin resistance and retention of biological activity and to assess the stability of the long-R3-IGF-I analogues under in vivo conditions using luminal stomach flushings. / Thesis (Ph.D.)--University of Adelaide, Dept. of Biochemistry, 1996

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Bibliography: leaf 141-157.

O Circovirus suíno tipo 2 (PCV2) é um vírus ubíquo que tem sido associado a um número de síndromes em suínos. Entre elas, a Síndrome Multissistêmica do Definhamento dos Suínos (SMDS) tornou-se uma das principais causas de perdas econômicas na suinocultura nacional. No entanto, existe incerteza se o PCV2 é, de fato, o único agente responsável por esse quadro, essencialmente porque a administração isolada do vírus a animais suscetíveis não tem sido capaz de reproduzir experimentalmente a síndrome. Em vista disso, um número de outros agentes infecciosos (e não infecciosos) tem sido examinados e sua potencial participação no desenvolvimento da SMDS tem sido pesquisada. No presente estudo foram realizados experimentos visando determinar se outro(s) agente(s) com genoma de DNA circular poderia(m) desempenhar algum papel no desenvolvimento da SMDS. Para tanto, a técnica denominada “amplificação por círculo rolante com múltiplos primers” (ACRMP) foi empregada. A ACRMP é baseada na atividade da DNA polimerase do fago phi29, uma enzima capaz de sintetizar novas moléculas de DNA a partir de um molde de DNA circular. Numa segunda etapa, o DNA amplificado é clivado com enzimas de restrição, ocasionando a linearização de grande quantidade de cópias do DNA alvo original. Como a ACRMP é realizada com primers aleatórios, nenhum conhecimento prévio da seqüência de nucleotídeos alvo é necessário. Portanto, pode-se teoricamente amplificar DNA circular de qualquer microorganismo, o que a torna ideal para o propósito do presente estudo. O DNA extraído de soros de 67 suínos com sinais clínicos de SMDS, assim como de 63 suínos saudáveis, foram submetidos à ACRMP. O principal achado deste estudo foi que o genoma de um (ou mais) anelovírus foi(ram) detectado(s) em 88,9% (56/63) dos suínos saudáveis, ao passo que o(s) mesmo(s) agente(s) somente foi(ram) detectado(s) em 16,4% (11/67) dos soros de suínos com sinais clínicos da SMDS. Alguns fragmentos de DNA potencialmente correspondentes a fragmentos de genomas virais foram seqüenciados, revelando que pelo menos um deles corresponde a uma seqüência de anelovírus suíno ainda não descrita. No entanto, outro genoma correspondente a um anelovírus foi encontrado na mesma amostra, sugerindo que mais de um vírus pode estar presente em amostras de soro. Estes resultados demonstraram que os anelovírus, de grande variabilidade genética, são significativamente mais prevalentes em suínos clinicamente saudáveis do que em suínos com SMDS. / Porcine circovirus type 2 (PCV2) is an ubiquitous virus that has been associated to a number of syndromes in swine. Among these, Postweaning Multisystemic Wasting Syndrome (PMWS) has become a major cause of economic losses in swine worldwide. However, there is uncertainty as to whether PCV2 is in fact the sole agent responsible for the disease, essentially because the disease has not been experimentally reproduced when PCV2 is inoculated onto susceptible animals. In view of that, a number of other infectious (and non infectious) agents have been examined and their potential role in PMWS searched for. This study was carried out to determine whether any other agent(s) with circular DNA genome might be playing some role in PMWS. In order to achieve that, a technique called “randomly primed rolling circle amplification” (RPRCA) was employed. RPRCA is based on the activity of bacteriophage phi29 DNA polymerase, an enzyme that synthesizes new DNA molecules starting from a circularized DNA template. In a second phase, the amplified DNA is cleaved with restriction enzymes, so giving rise to large amounts of linearized copies of the original target DNA. As RPRCA is performed with random priming, no previous knowledge of the target nucleotide sequence is necessary. Therefore, it is theoretically possible to amplify circular DNA of any microorganism, thus making it ideal for the purpose of the present study. DNA extracted from sera of 67 pigs with clinical signs of PMWS as well as from 63 healthy pigs was submitted to RPRCA. The major finding of this study was that the genome of one (or more) anelloviruses was detected in 88,9% (56/63) of the healthy pigs, whereas the same agent was only detected in 16,4% (11/67) of pigs with clinical signs of PMWS. Some of the DNA fragments corresponding to the putative virus genomes were sequenced and revealed at least one non-previously described anellovirus sequence. However, other anellovirus could be found on the same sample, suggesting that more than one genome are present in samples of serum. These results demonstrate that anelovírus, of great genetic variability, were significantly more prevalent in healthy pigs than in pigs with PMWS.

O Circovirus suíno tipo 2 (PCV2) é um vírus ubíquo que tem sido associado a um número de síndromes em suínos. Entre elas, a Síndrome Multissistêmica do Definhamento dos Suínos (SMDS) tornou-se uma das principais causas de perdas econômicas na suinocultura nacional. No entanto, existe incerteza se o PCV2 é, de fato, o único agente responsável por esse quadro, essencialmente porque a administração isolada do vírus a animais suscetíveis não tem sido capaz de reproduzir experimentalmente a síndrome. Em vista disso, um número de outros agentes infecciosos (e não infecciosos) tem sido examinados e sua potencial participação no desenvolvimento da SMDS tem sido pesquisada. No presente estudo foram realizados experimentos visando determinar se outro(s) agente(s) com genoma de DNA circular poderia(m) desempenhar algum papel no desenvolvimento da SMDS. Para tanto, a técnica denominada “amplificação por círculo rolante com múltiplos primers” (ACRMP) foi empregada. A ACRMP é baseada na atividade da DNA polimerase do fago phi29, uma enzima capaz de sintetizar novas moléculas de DNA a partir de um molde de DNA circular. Numa segunda etapa, o DNA amplificado é clivado com enzimas de restrição, ocasionando a linearização de grande quantidade de cópias do DNA alvo original. Como a ACRMP é realizada com primers aleatórios, nenhum conhecimento prévio da seqüência de nucleotídeos alvo é necessário. Portanto, pode-se teoricamente amplificar DNA circular de qualquer microorganismo, o que a torna ideal para o propósito do presente estudo. O DNA extraído de soros de 67 suínos com sinais clínicos de SMDS, assim como de 63 suínos saudáveis, foram submetidos à ACRMP. O principal achado deste estudo foi que o genoma de um (ou mais) anelovírus foi(ram) detectado(s) em 88,9% (56/63) dos suínos saudáveis, ao passo que o(s) mesmo(s) agente(s) somente foi(ram) detectado(s) em 16,4% (11/67) dos soros de suínos com sinais clínicos da SMDS. Alguns fragmentos de DNA potencialmente correspondentes a fragmentos de genomas virais foram seqüenciados, revelando que pelo menos um deles corresponde a uma seqüência de anelovírus suíno ainda não descrita. No entanto, outro genoma correspondente a um anelovírus foi encontrado na mesma amostra, sugerindo que mais de um vírus pode estar presente em amostras de soro. Estes resultados demonstraram que os anelovírus, de grande variabilidade genética, são significativamente mais prevalentes em suínos clinicamente saudáveis do que em suínos com SMDS. / Porcine circovirus type 2 (PCV2) is an ubiquitous virus that has been associated to a number of syndromes in swine. Among these, Postweaning Multisystemic Wasting Syndrome (PMWS) has become a major cause of economic losses in swine worldwide. However, there is uncertainty as to whether PCV2 is in fact the sole agent responsible for the disease, essentially because the disease has not been experimentally reproduced when PCV2 is inoculated onto susceptible animals. In view of that, a number of other infectious (and non infectious) agents have been examined and their potential role in PMWS searched for. This study was carried out to determine whether any other agent(s) with circular DNA genome might be playing some role in PMWS. In order to achieve that, a technique called “randomly primed rolling circle amplification” (RPRCA) was employed. RPRCA is based on the activity of bacteriophage phi29 DNA polymerase, an enzyme that synthesizes new DNA molecules starting from a circularized DNA template. In a second phase, the amplified DNA is cleaved with restriction enzymes, so giving rise to large amounts of linearized copies of the original target DNA. As RPRCA is performed with random priming, no previous knowledge of the target nucleotide sequence is necessary. Therefore, it is theoretically possible to amplify circular DNA of any microorganism, thus making it ideal for the purpose of the present study. DNA extracted from sera of 67 pigs with clinical signs of PMWS as well as from 63 healthy pigs was submitted to RPRCA. The major finding of this study was that the genome of one (or more) anelloviruses was detected in 88,9% (56/63) of the healthy pigs, whereas the same agent was only detected in 16,4% (11/67) of pigs with clinical signs of PMWS. Some of the DNA fragments corresponding to the putative virus genomes were sequenced and revealed at least one non-previously described anellovirus sequence. However, other anellovirus could be found on the same sample, suggesting that more than one genome are present in samples of serum. These results demonstrate that anelovírus, of great genetic variability, were significantly more prevalent in healthy pigs than in pigs with PMWS.