Abstract

Bovine parvovirus (BPV) is a helper-independent parvovirus. It has a small icosahedral capsid with a single stranded DNA genome. It is a highly stable virus with a narrow host range. It causes acute gastroenteritis in calves. It is considered to be a cytolytic virus because it kills the host cells. However, the mechanism by which the virus causes cell death is not known. The work described in this thesis assessed different parameters of cell death in BPV infected embryonic bovine tracheal (EBTr) cells. There are several ways for viruses to induce cell death. Viruses can induce apoptosis in the infected cell. They can also kill the host cell by necrosis. Several approaches were used in this work to look for evidence of apoptosis and necrosis. Cells undergoing apoptosis exhibit cardinal signs that distinguish them from other dying cells. Among these signs are the exposure of phosphatidylserine to the outer surface of the plasma membrane, DNA fragmentation into non-random DNA sections that are multimers of 180bp, nuclear morphology changes and caspase activation. These signs were studied in this research and data collected from these experiments did not show any positive sign of apoptosis in infected cells due to virus infection. Cells undergoing a necrotic cell death have a different pattern. The cells swell then burst releasing their cytoplasmic contents. The DNA is fragmented in a random fashion. Cellular morphology was studied in this research and the data suggested that BPV infected cells swell, then shrink and detach from the surface of the culture vessel. Moreover, formation of apoptotic bodies was not detected in dying infected cells. Release of cytoplasmic contents was also assessed by looking at concentrations of LDH enzyme, viral haemagglutinin, and the number of infectious viral particles in the media of infected cells. Data from the different approaches employed in this study do not support the hypothesis that BPV kills the infected EBTr cell by apoptosis, rather, infected cells in culture become necrotic, swell, release their cytoplasmic contents, and detach.

Degree

MS

College and Department

Life Sciences; Microbiology and Molecular Biology

Rights

http://lib.byu.edu/about/copyright/

Date Submitted

2005-06-22

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd857

Keywords

Bovine parvovirus, necrosis, apoptosis

Included in

Microbiology Commons

Share

COinS