Warm Regards and glad to receive the Scientific clipping on Viruses published in the Newsweek . It is really nice to note that you are interested in Viruses that can bring back life to a dead cell or human being. It is my duty to inform you as a Science student that the article is an exaggeration and a fine product of human imagination rather than a scientific fact. The article does not confirm to the scientific basis of Virology. Virology is the scientific study and research on Viruses. To understand viruses one must first understand unicellular organisms. Unicellular organisms are those organisms that are made-up of a single cell.
They are so small and can be seen only using an instrument called microscope. A cell is the structural and functional basis of life. These unicellular organisms have a definite cellular organization like cell wall and nucleic acids and multiply themselves by simple division of their cells into two. The nucleic acids in the cell, namely, DNA and RNA form the chemical basis of life. Plague causing bacteria is a classic example of unicellular organism. The viruses do not fall into the category of unicellular organisms because they do not have a definite cellular organization (Belshe et. al 1991).
They either have DNA or RNA and never both as seen in bacteria and other unicellular organisms. Viruses are obligate intracellular parasites (Collier et. al 1990), which means that they need another cell, usually called the host cell to multiply themselves. Thus, viruses cannot multiply on their own. They need another cell to multiply themselves. For this purpose of replication, the viruses invade a healthy cell, utilize the multiplication mechanism of the healthy cell and ultimately destroy them. This is called as viral infection of the host. For example, the well-known sexually transmitted disease AIDS is caused by a virus called HIV.
This virus attacks a specific portion on human cell surface called CD4 and gets attached firmly. (Our blood also contains cells that have CD4 component). In case of viruses that cause influenza fever, the viruses get attached to the cells of the respiratory tract. This process of attachment to the prospective host cells by the virus is called adsorption. Once the virus firmly attaches itself to a cell, it invades the cell by a slow penetration process followed by the removal of a capsule like structure in the virus (Tom Elliott et. al 1997). This facilitates the nucleic acid of the virus literally taking control of the host cell mechanisms.
The virus multiplies itself, manufactures all its cellular requirements using the host cell. The thus formed viral units get released from the host by destroying the host cell in some cases, called the cell lysis or by a process called budding where the viral units are thrown out without destroying the host cell. These viruses are pathogenic in nature, which means that they can cause a wide range of diseases in human beings and animals. AIDS, Hepatitis, Rabies, Measles, Small pox, Cancer and Flu fever are some of the well-known diseases caused by these viruses.
A scientist Stanley by name demonstrated in 1935 that viruses could be crystallized like other chemicals. This sparked a controversy that viruses are just chemicals and not living organisms. But subsequent experiments in 1956 by Geirer and Schramm (Dimock et. al 1987) showed that the chemical nucleic acids in the viruses could create a population of viral progeny in a living cell thus proving that viruses are indeed living cells. Of course, they are the smallest living units. The largest of the viruses are only as large as the smallest bacteria. The smallest viruses are as small as some blood