Viruses are unable to survive independently, so they multiply by parasitizing on their hosts. This characteristic makes them disease-causing, but modern medicine has harnessed them as an important tool to produce cures and vaccines by using genetic recombination techniques.
Viruses are usually about one-hundredth the size of bacteria and are composed entirely of proteins and nucleic acids. They don’t have the structure of a cell, so they can’t metabolize on their own. However, these tiny particles survive through a very clever biological strategy. In order to replicate and spread themselves, viruses must parasitize living organisms, or hosts. The host is the organism that nourishes the parasite and provides it with a place to live. Viruses enter the host’s cells, inject their genetic material, and use the host’s resources to replicate and multiply. This process is costly to the host.
This would be fine if viruses only used other organisms to survive, but their “parasitic” way of survival is problematic because it inevitably causes damage to the host. By destroying or altering the host cells, the host organism becomes susceptible to a variety of diseases. How do viruses harm their hosts? First, viruses attach to the surface of the cells of their hosts – microorganisms, plants, and animals – and introduce their genetic material into the cell. Once inside the cell, the genetic material uses the host cell’s protein synthesis machinery to make the enzymes necessary for viral replication. The virus uses these enzymes to massively replicate its genetic material, and from the replicated genetic material, a new virus is formed through an assembly process in which the genetic material of the virus enters the protein shell. The number of viruses that can replicate in a single host cell is enormous. By repeating this replication process, the virus rapidly spreads within the host, causing the host organism to suffer from severe disease.
The multiplied viruses then break out of the host cell and reenter other neighboring host cells. Of course, the original host cell dies. Once the host cell is destroyed by the virus, the host’s bodily functions are severely affected, and various viral diseases occur. If the host is a human, this process can take place many times, resulting in the destruction of a large number of host cells and the development of various viral diseases such as chickenpox, epidemic eye disease, flu, and AIDS. Unlike bacterial diseases, there are few medicines to treat viral diseases. To treat viral diseases, you need to eliminate the virus that has entered the body, and it’s difficult to kill only the virus while leaving the host cells intact. For this reason, viruses have historically been perceived as negative entities.
However, recent interest in genetic recombinant technology has shown that viruses can do beneficial things for humans. Genetic recombination technology is opening up new possibilities in biotechnology and medicine by harnessing the properties of viruses. The synthesis of useful genes by creating useful DNA (the gene body that combines with proteins to form an important component of the chromosomes in a cell) from an organism and inserting it into a host cell, such as E. coli, is called genetic recombination technology. One of the gene carriers used in this process is a bacteriophage, a type of virus. Bacteriophages attach to the cell surface of bacteria and then introduce their genetic material into the bacterial cell, where they multiply in large numbers and eventually destroy the host.
Modern medicine utilizes this genetic recombination technique to produce insulin to treat diabetes. Bacteriophages are inserted into E. coli with the DNA needed to synthesize insulin, which is then replicated to produce artificially large amounts of insulin to make insulin injections. While insulin injections only supplement insulin deficiencies, they are a breakthrough compared to traditional treatments that rely on obtaining insulin from animals. Furthermore, this technology is being used to produce not only insulin but also various drugs and vaccines, showing that viruses can be used as a tool to treat diseases as well as cause them. This is why viruses, which were once thought of as negative entities that cause disease and destroy host cells, are becoming an important focus of modern medicine.
