Currently, the concept of the cell as a society or an ecosystem of molecular elements is gaining increasing acceptance. The basic idea arose in the 19th century, from the surmise that there is not just a single unit underlying an individual's appearance , but a plurality of entities with both collaborative and conflicting relationships. The following hypothesis is based around this model. The incompatible activities taking place between different original elements, which were subsumed into the first cell and could not be eliminated, had to be controlled very closely. Similarly, a strong level of control had to be developed over many cellular elements after the cell changed its genome to DNA. We assume that at least some of those original RNA agents and other biomolecules which carry incompatibilities and risks, are retained within current cells, although they are now under strict control. A virus functions as a signal informing these repressed cellular RNAs and other elements of ancient origin how to restore suppressed degrees of molecular freedom, favoring pre-existing molecular affinities and activities, re-establishing ancient molecular webs of interactions, and giving fragments of ancient coded information (mostly in the form of RNA structural motifs) the opportunity to be re-expressed. Collectively, these newly activated mechanisms lead to different possibilities for pathological cell states. All these processes are opposed by cell-control mechanisms. Thus, in this new scenario, the battle is considered intracellular rather than between the virus and the cell. And so the virus is treated as the signal that precipitates the cell's change from a latent to an active pathological state.

2004

This paper traces the beginnings of structural virology, from the early 1950's to the presentation of the Caspar-Klug theory of virus structure in 1962. It focuses primarily on the virus research of Francis Crick,

Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences, 2016

• Even though it has been neglected, the study of viruses raises important philosophical questions. • Questions about viruses (definition, classification, etc.) can be related to classic issues in philosophy of biology and general philosophy. • The contributions gathered in this special issue address these questions in different and sometimes conflicting ways.

Reviews in Medical Virology, 1991

- Even though it has been neglected, the study of viruses raises important philosophical questions. - Questions about viruses (definition, classification, etc.) can be related to classic issues in philosophy of biology and general philosophy. - The contributions gathered in this special issue address these questions in different and sometimes conflicting ways.

2001

Journal of Theoretical Biology, 2008

The Caspar-Klug classification of viruses whose protein shell, called viral capsid, exhibits icosahedral symmetry, has recently been extended to incorporate viruses whose capsid proteins are exclusively organised in pentamers. The approach, named 'Viral Tiling Theory', is inspired by the theory of quasicrystals, where aperiodic Penrose tilings enjoy 5-fold and 10-fold local symmetries. This paper analyzes the extent to which this classification approach informs dynamical properties of the viral capsids, in particular the pattern of Raman active modes of vibrations, which can be observed experimentally. 4 Observations indicate that the RNA release in the Tomato Bushy Stunt Virus happens through tiny apertures located at local symmetry axes of the icosahedral capsid, whose formation is consistent with the effect of certain normal modes of vibration .

2010

RNA viruses offer a very exciting arena in which to study evolution in 'real time' owing to both their high replication rate-many generations per day are possible-and their high mutation rate, leading to a large phenotypic variety. They can be regarded as a swarm of genetically related mutants around a dominant or master genetic sequence. This system is called a 'viral quasi-species'. Thus, a common framework to describe RNA viral dynamics is by means of the quasi-species equation (QSE). The QSE is in fact a system of a very large number of nonlinear coupled equations. Here, we consider a simpler formulation in terms of 'error classes', which groups all the sequences differing from the master sequence by the same number of genomic differences into one population class. From this, based on the analogies with Bose condensation, we use thermodynamic inspired observables to analyse and characterize the 'phase transition' through the socalled 'RNA virus error catastrophe'.

The Pharma Innovation Journal, 2020

The inhibition of viral reproduction caused by previous exposure of cells to another virus is popularly known as viral interference or superinfection resistance. The primary virus infecting the cell prevents the replication of secondary virus in that cell, thus making viral interference a very important phenomenon in viral world. It may be simplified by stating that the virus can suppress the shedding of a new virus of the homologous or heterologous type which enters the cell. The mechanisms proposed to explain viral interference may be briefly described as competing by attachment interference where receptors for the superinfecting virus are reduced or blocked, competing for intracellular components required for replication of the host machinery and virus induced interferon interference. The intensity of viral interference however depends on several factors such as adaptation of viruses to host species, pathogenicity of viruses, time of co-infection, and environmental factors. This ...

Virology, 1973