Which Cytopathic effect causes 1 Degradation of the nucleus

Which Cytopathic effect causes:

1, Degradation of the nucleus?

2. Floating cells ?

Solution

Cytopathic effect (CPE) refers to the structural changes that occur in the host cell due to virus invasion. Cytopathic effect is therefore, most commonly utilized as a criterion for viral infection. Although, all viruses do not produce a cytopathic effect. CPE is comprised of 2 main phenomena; namely, morphological alterations and inclusion bodies, which are more subtle changes. Morphological changes involve, rounding, shrinking, fusion, aggregation, increased refractility, loss of adherence and lysis. While, inclusion bodies referes to the presence of abnormalities in the cell as compared to an uninfected cell. A cytopathic effect may also be seen in tissue cultured cells infected with a virus.

1) Nucleus degradation may be seen as an effect of virion replication. Virus replication in some cases depends on the nuclear machinery of the infected cell i.e. it takes over the entire machinery of the cell so as to transcribe and translate proteins which would aid in formation of new virion particles. After replication of the virus, large number of virion particles are released when the cell undergoes lysis.

2) We may observe that adherent cells that are normally attached to other cells (in vivo) or to an artificial substrate, may assume a rounded shape as opposed to their characteristic flattened shape and the cellular extensions (involved in motility or attachment) have been drawn in, due to a viral infection. These effects my be a result of partial degradation of the cytoskeleton. The result of this can be seen in monolayer culture, where virus infection causes detachment of cells. Clumping and shrinkage may also result in detachment of cells from the tissue layer. This causes the cells to float in the medium. Floating cells may also arise due to apoptosis.