VIRUSES – THE BETTER PART OF THE WORST

Editor

Science is working overtime to use viruses for the benefit of mankind!!!

Viruses are tiny biological infectious entities capable of infecting all possible life forms, from microbes to human. Viruses, unlike other simple microorganisms, has just two components – (1) Genetic material (DNA or RNA) and (2) A protein coat to cover the DNA genetic material.

Although they have genes, they do not have a cellular structure, which is often seen as the basic unit of life. Virus infects a cell by simply injecting its genetic material inside the cell. This genetic material is like a chip containing all the information needed to exploit the cell’s machinery for its own use.

Fortunately, viruses are incapable of surviving on their own and can become active only if they successfully infect a living cell which then serves as a host harbouring the viruses.

Barriers against Viruses

1)    Human skin prevents the virus from infecting the body; acidity of stomach also kills the viruses which enter with food.

2)    Plants also secrete many disinfectants to protect themselves from the viruses; plants possess special genes working to prevent viral infections.

3)    Not just plants and animals, viruses also infect bacterial cells. Such viruses are known as bacteriophages. Bacteria produce enzymes to defend themselves from bacteriophages.

4)    When viruses pass physical barriers, the human liver produces 20 types of proteins which destroys them.

5)    Innate (natural) immune system works as second line of defense in fighting against viruses.

6)    As a third line of defense, adaptive (acquired) immune system works against viruses via antibodies, B-cells and T-cells.

ST

The better part of the viruses

AS PEST CONTROLLER

Insect-specific viruses can be highly effective natural controls for several pests. Baculoviruses for example, are pathogens that attack insects and shows a high level of environmental stability due to formation of thick protein shells, known as occlusion bodies (OBs), around the nucleocapsid that contains the viral DNA genome. As part of their natural infectious cycle, Baculoviruses are eaten by insect larvae. They then infect the cells of the gut and grow there. From these cells, the virus can then spread throughout the body of the insect causing its death in 4 to 5 days.

 

AS RABBIT CONTROLLER

The Myxoma virus is a member of the Poxviridae, and was originally observed as a cause of a mild skin disease in American rabbits in Uruguay in the late nineteenth century. From 1938 onward it was evaluated as a possible control agent for introduced European rabbits in Australia. It was finally released in 1950 and proved highly effective, reducing the rabbit population by an estimated 500 million (around 85%) in two years.

VIRUSES AS BACTERIA CLEANER

Bacteriophages are highly specific viruses that can target, infect, and destroy specific bacteria. Through phage therapy, bacteriophage is used to destroy the infective bacteria such as E. coli or Salmonella. It is also used in identifying pathogenic bacteria in diagnostic laboratories.

ACTIVATING PRODRUGS

Viruses may also be used to activate an inactive cytotoxic drug (a prodrug) that is administered. Thus, the active, cytotoxic form of the drug is only produced where the relevant enzyme is present. For example, an adenovirus expressing the thymidine kinase (TK) enzyme of herpes simplex virus can be combined with ganciclovir, which is converted by the TK to its active form only in cells where this enzyme is present.

FOR SAFER FOOD, JUST ADD VIRUSES

Bacteriophages is used for killing specific bacteria found in food. For example, LISTEX by Micreos is made up of bacteriophages that can kill the L- monocytogenes bacteria in cheese.

VACCINES PRODUCTION

Vaccines are made using the same components that are found in the natural virus.  Either the viruses are weakened so they reproduce very poorly once inside the body like the vaccines for measles, mumps, German  measles (rubella), rotavirus, oral polio, intranasal influenza. In another strategy, just one part of the virus is removed and used as a vaccine. The hepatitis B and HPV vaccines are made this way.

Source: Soft Vision Research Centre