Thesis (M.Sc.)--York University, 2008. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 94-99). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38791

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Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 227-245). Also available on the World Wide Web.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xii, 133 p.; also includes graphics. Includes abstract and vita. Advisor:, Dept. of Molecular, Cellular, and Developmental Biology. Includes bibliographical references (p. 108-133).

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Respiratory infection is a major disease burden worldwide. Statistical reports revealed it is one of the main causes of mortality and morbidity especially in young children. Influenza infection is one of the predominant cause associate with respiratory infection. Traditionally, studies have been emphasized on the detection of influenza A and B virus owing to their significance in clinical and economic impact. Attention of influenza C virus is rarely recognized due to its difficulty in isolation. However, recently, increasing reports have been illustrated the co-circulation of influenza C virus globally. Serological studies also suggested majority of people worldwide acquired influenza C virus infection in their early childhood or adolescent stage, yet information regarding influenza C virus is still inadequate. Epidemiological and clinical impact of influenza C virus in pediatric patients in Hong Kong was examined by the approach of real-time PCR. From November 2007 to April 2011, a total of 1, 037 specimens were obtained from pediatric patients exhibited apparent respiratory tract illness in Hong Kong. Eleven strains of influenza C virus were detected by real-time PCR approach. All patients with influenza C virus infection were below 5 years of age with the youngest age of 11 months. The ratio of infection in male to female was approximately one to one. High grade fever appeared to be the most frequent clinical manifestations (10/11) of influenza C virus infection. Upper respiratory tract infection was also occasionally observed. The clinical presentation of influenza C virus was similar to its influenza counterpart. Phylogenetic analysis of influenza C virus was examined in 6/11 of the isolates to determine the lineages of co-circulating influenza C viruses in Hong Kong. Nucleotide sequencing was performed with primer targeting the hemagglutinin-esterase (HE) gene. Result revealed that most of the detected influenza C virus associate with the C/Sao Paulo/378/82 related lineage. Results from this study revealed the positive rate of influenza C was comparable to influenza B and resultant respiratory symptoms could be severe in pediatric patients It is suggested to consider the inclusion of influenza C virus detection in routine diagnostic panel and real-time PCR could be a desirable detection platform account for its sensitivity and rapidity. / published_or_final_version / Microbiology / Master / Master of Medical Sciences

Most emerging infectious diseases in humans are zoonotic agents. Since the emergence of severe acute respiratory syndrome (SARS), swine-origin influenza and avian influenza epidemics, the study of novel and emerging viruses with zoonotic potential has been considered more and more important. Paramyxoviruses have been known for their potential to cross species barrier and infect new hosts. In the last decade, a number of novel and emerging paramyxoviruses have been reported in various animals. Our research group recently identified three novel bat paramyxoviruses, Tuhoko viruses 1, 2 and 3 (ThkPV-1, 2, and 3) from fruit bats in mainland China, an unclassified paramyxovirus, named Tailam virus (TlmPV) from Sikkim rats and a novel feline paramyxovirus, called Feline morbillivirus(FmoPV) from domestic cats in Hong Kong, suggesting that there is still a diversity of undescribed paramyxoviruses in animals. In this study, a novel porcine paramyxovirus, Swine parainfluenza virus 1 (SpiPV-1), was discovered and characterized from deceased pigs in Hong Kong. A total of 951 samples from 386 deceased pigs were collected, including 386 nasopharyngeal swab, 303 rectal swab, 153 blood, 56 lung and 53 liver samples. And SpiPV-1 was detected in 12 (3.1%) of 386 nasopharyngeal swab and 2 (0.7%) of 303 rectal swab samples by RT-PCR. All the blood, lung and liver samples showed negative results. The complete genome sequences of three strains (SpiPV-1 S033N, SpiPV-1 S119N and SpiPV-1 S206N) from three pigs were amplified and determined. The genome organization of SpiPV-1 is similar to that of viruses under genus Respirovirus, subfamily Paramyxovirinae. The genome contains six genes (3’-N-P/V/C-M-F-HN-L-5’) and putatively codes for the nucleocapsid (N), phosphoprotein (P/V/C), matrix (M), fusion (F), attachment (HN) and large (L) proteins.Like other respiroviruses, the P gene of SpiPV-1 can produce more than one protein, including P, V and W proteins by mRNA editing and C protein by alternative translation initiation. And phylogenetic analysis showed that in all six phylogenetic trees constructed byusing the N, P, M, F, HN and L genes, the three strains SpiPV-1 S033N, S119N and S206N formed a distinct cluster among the known respiroviruses and were most closely related to Sendai virus (SenPV) and Human parainfluenza virus 1 (HpiPV-1). The genome organization, P gene analysis and phylogenetic analysis all suggested that SpiPV-1 is a novel paramyxovirus under genus Respirovirus, subfamily Paramyxovirinae. Seven porcine samples positive for SpiPV-1 were cultured in five different cell lines for viral isolation. However, no cytopathic effect was observed and no viral replication was detected in any of the cell lines. The pathogenicity and emergent potential of SpiPV-1 remain to be determined. Further studies on serology and development of cell cultures for viral isolation may provide better insight into this novel paramyxovirus. / published_or_final_version / Microbiology / Master / Master of Philosophy

The life cycle of enveloped viruses is a complex process relying on specific interactions with host factors that, in turn, represent potential targets for interfering with viral replication and pathogenesis. Although the molecular identity of cellular receptors involved in virion entry has been established for many viruses, few studies have investigated whether host proteins on intracellular compartments may function as receptors to facilitate viral trafficking and release from infected cells. In particular, viral-host interactions during dengue virus (DENV) egress are still poorly characterized and most cellular targets identified in high-throughput screens have not been mapped to the secretory pathway. DENV structural glycoproteins, pre-membrane (prM) and envelope (E), are sufficient to assemble native Recombinant Subviral Particles (RSPs) in the endoplasmic reticulum (ER). Newly formed RSPs mimic nascent virions and traffic through the secretory pathway, where they are processed into mature particles, before being released from cells. This study demonstrated that DENV requires host KDEL receptors (KDELRs), which cycle between the ER and Golgi apparatus to retrieve resident ER proteins, for vesicular transport from ER to Golgi. Depletion of KDELRs by siRNA reduced egress of both DENV progeny virions and RSPs produced in stable cell lines expressing prM and E. A direct interaction between KDELRs and DENV prM was demonstrated in either prME expressing or DENV infected cells by co-immunoprecipitation (co-IP) experiments. By immunoblotting with specific antibodies we first showed that KDELRs interacted with prM portion. By interfering with RSPs’ maturation, we then obtained conclusive evidence that interaction was restricted to the pr fragment which released from the mature RSPs after cleavage of prM by cellular protease furin. This finding was further confirmed by GST pull down assay, which mapped the interacting domain to the N-terminal 40 residues of the pr fragment, and by mutagenesis experiments, which showed that KDELRs interact with prM through three positively charged amino-terminal residues. Biochemical analysis and immunofluorescence microscopy indicated that mutations impairing KDELRs/prM binding did not affect RSPs formation, and translocation within the ER, whereas they strongly inhibited trafficking from ER to Golgi apparatus and, consequently, their release into the supernatant. Moreover, perturbation of KDELR cycle by siRNA-mediated depletion of class II Arfs, which accumulates KDELRs in the Golgi, phenocopied results obtained with both an interaction-deficient mutant and KDELR knockdowns. Finally, we compared the effect of KDELRs on all four DENV serotypes and found significant reductions of DENV1-3, but not DENV4, in keeping with the co-IP results that demonstrated, using RSP-producing cell lines, that only DENV1-3 prM proteins interacted with KDELRs. Of note, KDELRs depletion did not affect West Nile Virus progeny virus egress, suggesting that KDELRs might not be utilized by all Flavivirus. Taken together, several lines of evidence have been presented to indicate that the loss of interaction with KDELRs reduced DENV transport from ER to Golgi and, consequently, release from infected cells. These findings, therefore, have uncovered a novel function for KDELRs as an internal receptor required for DENV trafficking and identified a rate-limiting molecular step in the late stages of DENV lifecycle. / published_or_final_version / Public Health / Doctoral / Doctor of Philosophy

published_or_final_version / Computer Science and Information Systems / Master / Master of Philosophy