• Bovine enterovirus as an oncolytic virus: foetal calf serum facilitates its infection of human cells.

      Smyth, M.S.; Symonds, A.; Brazinova, S.; Martin, Jan H. (University of Crete, 2002)
      Many viruses have been investigated for their oncolytic properties and potential use as therapeutic agents for cancer treatment. Most of these replication-competent viruses are human pathogens. We investigated the oncolytic properties of an animal virus which is non pathogenic for both its natural host and humans. Bovine enterovirus has previously been shown to exhibit a very wide tissue tropism for cell types in vitro. We compare the ability of bovine enterovirus to replicate in and to cause cytopathic effect in freshly isolated human monocytes and monocyte derived macrophages with the monocyte-like U937 tumour cell line. We also include the adherent ZR-75-1 human breast cancer cell line. We have also carried out infections of bovine enterovirus in the presence and in the absence of serum of bovine origin. Our study shows that the virus will replicate in and produce cytopathic effect in the U937 and ZR-75-1 cell types to the same extent as the cells (BHK-21) in which the virus is routinely propagated. We believe bovine enterovirus to be a worthwhile candidate for further study as an anti-tumour agent.
    • Identification of the pocket factors in a picornavirus

      Smyth, M.S.; Martin, Jan H.; Pettitt, T.; Symonds, A. (Springer Wien, 2003)
      Bovine enterovirus (BEV), along with other enteroviruses and the rhinoviruses, has a hydrophobic pocket within structural protein VP1. In the crystal structures of these viruses there is electron density commensurate with a non-protein molecule within the pocket. These molecules, termed pocket factors, have been shown to stabilise the capsid and their removal from the pocket is a necessary prerequisite to uncoating. The pocket factors have been proposed, from the electron densities and uncoating studies, to be short chain fatty acids. In order to identify the pocket factor of BEV, we have grown and purified the virus in an identical manner to that used for the crystal structure determination and have performed a lipophilic extraction. Palmitic acid, C16:0, was the most abundant accounting for 40.8% by mass of the lipophilic extract (39.3 mol%). Myristic acid C14:0, was next most abundant at 18.5% by mass (20.0 mol%). In addition, we have identified other fatty acids in smaller proportions. We have therefore shown that BEV contains saturated fatty acid pocket factors of varying chain length. We have also compared the profile of the fatty acyl chain composition of BEV with those for uninfected BHK-21 cell plasma membrane and endoplasmic reticulum extracts.
    • Picornavirus uncoating.

      Smyth, M.S.; Martin, Jan H. (British Medical Association, 2002)
      Recently, much has been learned about the molecular mechanisms involved in the pathogenesis of picornaviruses. This has been accelerated by the solving of the crystal structures of many members of this virus family. However, one stage of the virus life cycle remains poorly understood: uncoating. How do these simple but efficient pathogens protect their RNA genomes with a stable protein shell and yet manage to uncoat this genome at precisely the right time during infection? The purpose of this article is to review the current state of knowledge and the most recent theories that attempt to answer this question. The review is based extensively on structural data but also makes reference to the wealth of biochemical information on the topic.
    • Structural, biochemical and electrostatic basis of serotype specificity in bovine enteroviruses

      Smyth, M.S.; Martin, Jan H. (Springer Wien, 2001)
      We have performed immunostructural analyses of three closely related picornaviruses in order to gain understanding of the biochemical and structural basis of serotype specificity. We carried out sequence alignments of the capsid regions of three bovine enterovirus strains: VG-5-27 and M-4 from serotype 1 and PS-87 from serotype 2. Using our knowledge of the three dimensional and antigenic structure of strain VG-5-27 and the high levels of sequence identity between the strains, we have calculated the structures and solvent-accessible electrostatic potentials of the epitopes of all three viruses. We have demonstrated the viability of the molecular models of the epitopes of the M-4 and PS-87 strains. In each of the strains, we have explained the serotype specificities in terms of specific physical and chemical properties, and identified individual residues which are pivotal in determination of antibody recognition. These changes are in agreement with the known cross-reactivity of peptide and antiviral sera, showing that it is possible to derive structures for short variable sections of proteins of high sequence identity using molecular modelling which are significant in terms of biological function. We believe this study to be a novel approach in the analysis of virus serotype specificity.