Biological Virus

Discovered by : Dimitri Iosifovich Ivanov

Discovered in year : 1890

Biological Virus is type of submicroscopic parasites that can infect any animal, plant or bacteria and often lead to very serious or even deadly diseases. A virus consists of a core of RNA or DNA, generally surrounded by a protein, lipid or glycoprotein coat, or some combination of the three. No virus can replicate without the help of a host cell and though they can spread rapidly , viruses lack the ability of self-reproduction and are not always considered to be living organisms in the regular sense. Some of the most common or best known viruses include the human immunodeficiency virus (HIV), which is the virus that causes AIDS, the herpes simplex virus, which causes cold sores, smallpox, multiple sclerosis, and the human papilloma virus now believed to be a leading cause of cervical cancer in adult women. The common human cold is also caused by a virus.

History

Dimitri Iosifovich Ivanovsky, a Russian microbiologist is regarded as the discoverer of biological virus. In 1887, while studying at St. Petersburg University, he was asked to investigate 'Wildfire' disease. This disease was infecting tobacco plantations of the Ukraine and Bessarabia. In 1890, he was commissioned to study a different disease that was destroying tobacco plants in the Crimea. From his research of both diseases, he determined that the infection was mosaic disease, which was believed at the time to be caused by bacteria. Using a filtering method for the isolation of bacteria, Ivanovsky discovered that filtered sap from diseased plants could transfer the infection to healthy plants. Further researches led Ivanovsky to conclude that the causal agent was an exceedingly small parasitic micro-organism that was invisible even under great magnification and that could permeate porcelain filters designed to trap ordinary bacteria. He differed from later researchers of viruses only in his supposition that the pathogenic agent in question was a minuscule bacterium, rather than an entirely new and different type of organism. He published his findings in an article, 'On Two Diseases of Tobacco' in1892 and a dissertation, Mosaic Disease in Tobacco in 1902. Although he is generally credited as the discoverer of viruses, they were also independently discovered and named by the Dutch botanist M.W. Beijerinck only a few years later.

Development in the discovery of biological virus

In 1898, Martinus Beijerinck, a Dutch microbiologist,  repeated the experiments and became convinced that this was a new form of infectious agent. He went on to observe that the agent multiplied only in dividing cells, but as his experiments did not show that it was made of particles, he called it a contagium vivum fluidum (soluble living germ). Later he termed these as virus. Beijerinck maintained that viruses were liquid in nature.

In 1899, Friedrich Loeffler and Frosch passed the agent of foot-and-mouth disease (aphthovirus) through a similar filter and ruled out the possibility of a toxin because of the high dilution; they concluded that the agent could replicate. In the early 20th century, the English bacteriologist Frederick Twort discovered the viruses that infect bacteria, which are now called bacteriophages and the French-Canadian microbiologist Félix d'Herelle described viruses that, when added to bacteria on agar, would produce areas of dead bacteria. He accurately diluted a suspension of these viruses and discovered that the highest dilutions, rather than killing all the bacteria, formed discrete areas of dead organisms. Counting these areas and multiplying by the dilution factor allowed him to calculate the number of viruses in the suspension

In 1906, Harrison invented a method for growing tissue in lymph, and, in 1913, E. Steinhardt, C. Israeli, and R. A. Lambert used this method to grow vaccinia virus in fragments of guinea pig corneal tissue. In 1928, H. B. Maitland and M. C. Maitland grew vaccinia virus in suspensions of minced hens' kidneys.

In 1931, Ernest William Goodpasture, an american pathologist grew influenza and several other viruses in fertilised chickens' eggs. In 1949 John F. Enders, Thomas Weller, and Frederick Robbins grew polio virus in cultured human embryo cells, the first virus to be grown without using solid animal tissue or eggs. This work enabled Jonas Salk to make an effective polio vaccine.

In 1957, Equine Arterivirus and the cause of Bovine Virus diarrhea (a pestivirus) were discovered. In 1963, Baruch Blumberg, discovered the hepatitis B virus and in 1965, Howard Temin, described the first retrovirus. By 1970, Howard Temin and David Baltimore described Reverse transcriptase, the key enzyme that retroviruses use to translate their RNA into DNA, through independent research. In 1983 Luc Montagnier's team at the Pasteur Institute in France, first isolated the retrovirus now called HIV.

Role of the discovery of biological virus in the improvement of human life

• It helped in the better understanding of diseases, it's prevention and treatment.

• Various types of viruses were identified owing to the first discovery of virus.

• Peopel became more aware of maintaining healthy hygiene.