19 research outputs found
Comparative studies on the pathogenicity and tissue distribution of three virulence variants of classical swine fever virus, two field isolates and one vaccine strain, with special regard to immunohistochemical investigations
<p>Abstract</p> <p>Background</p> <p>The aim of this study was to compare the tissue distribution and pathogenicity of three virulence variants of classical swine fever virus (CSFV) and to investigate the applicability of various conventional diagnostic procedures.</p> <p>Methods</p> <p>64 pigs were divided into three groups and infected with the highly virulent isolate ISS/60, the moderately virulent isolate Wingene'93 and the live attenuated vaccine strain Riems, respectively. Clinical signs, gross and histopathological changes were compared in relation to time elapsed post infection. Virus spread in various organs was followed by virus isolation, by immunohistochemistry, applying monoclonal antibodies in a two-step method and by <it>in situ </it>hybridisation using a digoxigenin-labelled riboprobe.</p> <p>Results</p> <p>The tissue distribution data are discussed in details, analyzing the results of the various diagnostic approaches. The comparative studies revealed remarkable differences in the onset of clinical signs as well as in the development of the macro- and microscopical changes, and in the tissue distribution of CSFV in the three experimental groups.</p> <p>Conclusion</p> <p>The present study demonstrates that in the case of highly and moderately virulent virus variants the virulence does not affect the pattern of the viral spread, however, it influences the outcome, the duration and the intensity of the disease. Immunohistochemistry has the advantage to allow the rapid detection and localisation of the virus, especially in cases of early infection, when clinical signs are still absent. Compared to virus isolation, the advantage of this method is that no cell culture facilities are required. Thus, immunohistochemistry provides simple and sensitive tools for the prompt detection of newly emerging variants of CSFV, including the viruses of very mild virulence.</p
Allosteric Transitions of Supramolecular Systems Explored by Network Models: Application to Chaperonin GroEL
Identification of pathways involved in the structural transitions of biomolecular
systems is often complicated by the transient nature of the conformations
visited across energy barriers and the multiplicity of paths accessible in the
multidimensional energy landscape. This task becomes even more challenging in
exploring molecular systems on the order of megadaltons. Coarse-grained models
that lend themselves to analytical solutions appear to be the only possible
means of approaching such cases. Motivated by the utility of elastic network
models for describing the collective dynamics of biomolecular systems and by the
growing theoretical and experimental evidence in support of the intrinsic
accessibility of functional substates, we introduce a new method,
adaptive anisotropic network model (aANM),
for exploring functional transitions. Application to bacterial chaperonin GroEL
and comparisons with experimental data, results from action minimization
algorithm, and previous simulations support the utility of aANM
as a computationally efficient, yet physically plausible, tool for unraveling
potential transition pathways sampled by large complexes/assemblies. An
important outcome is the assessment of the critical inter-residue interactions
formed/broken near the transition state(s), most of which involve conserved
residues