Virus Taxonomy & The Nature of Viruses

A virus is a small submicroscopic viral agent that replicates inside an organism’s living cells. Viruses can infect all living cell types, from simple bacteria and plants to organisms, such as Archaea and yeast, which are aerobic. A virus can cause infection by damaging the genetic material within a living cell, or it can cause a cell to divide abnormally and die. Most viruses are not deadly, however; they merely perturb the normal operations of an organism.

The study of viruses and their role in the microbial world has become a subject of tremendous research over the past half century. Much of this research has been done using experimental techniques and on living organisms, for example Escherichia coli (which produces many useful antibiotics), retroviruses (which caused a genus of diseases known as retroviruses) and bacteriophages (which destroy invading bacteria). Some viruses have been shown to be important in the development of certain types of cancers. There is also considerable controversy about whether some viruses are capable of resistance against common types of antibiotics.

Most viruses reproduce by inserting their genetic material, or coding, into the DNA of a living cell. In most cases, the insertion occurs without any noticeable change on the surface of the cells, allowing the virus to replicate and spread rapidly between organisms. Occasionally, the virus may produce a protein envelope that covers and protects the coding, allowing the insertion to be transmitted more easily between organisms.

Some viruses reproduce by means of a different process. Some produce particles, or proteins, that can latch onto other molecules in the environment. These particles can then latch onto other molecules, creating a chain reaction that causes the original virus to replicate. This method of reproduction is favored in many instances because the viruses’ ability to duplicate can be interfered with without killing the organism that the virus is trying to infect.

In order to produce a virus, a protein called a capsomer is required. The capsomer attaches itself to the viral particles, or genetic material, and produces a piece of the viral RNA. This piece of RNA is then picked up by the target cells, where it replicates itself many times over. Sometimes, the capsomer or viral RNA is detached from the target cells, and the process starts all over. Often, the capsomer is attached at a specific location so that it can make repeated copies of itself, making the virus active.

The structure of a virus is highly complicated, and it is often very difficult to understand, even for the scientists who study them. The structure also varies between different types of viruses, as well as between hosts and between geographic regions. Although many aspects of virus-like structures can be studied using molecular biology, only very recently have researchers been able to use the same technologies to study completely organic forms of life. Understanding biological viruses is still in its infancy, but the field is undoubtedly going to become increasingly more complex as more researchers gain access to more specific and powerful tools. We are already seeing this with the field of virology, where every year brings new and powerful techniques and technologies.