principle of biotechnology

PRINCIPLES OF BIOTECHNOLOGY

Biotechnology can be broadly defined as "using living organisms or their products for commercial purposes".

As such, biotechnology has been practiced by human society since the beginning of recorded history in such activities as baking bread, brewing alcoholic beverages, or breeding food crops or domestic animals.

A narrower and more specific definition of biotechnology is "the commercial application of living organisms or their products, which involves the deliberate manipulation of their DNA molecules".

This definition implies a set of laboratory techniques developed within the last 20 years that have been responsible for the tremendous scientific and commercial interest in biotechnology.

Some other available definitions of biotechnology are :

''The application of biological organism, system or processes to manufacturing & service industries".

-British Biotechnologist

"The integrated use of biochemistry, microbiology & genetic engineering sciences in order to achieve technological (industrial) application of capabilities of micro-organisms, cultured tissue cells & parts there of".

-European Federation of Biotechnology

"The controlled use of biological agents, such as micro-organisms or cellular components, for beneficial use ".

-US National Science Foundation

Development of biotechnology may be studied considering its growth that occurred in two phases : (1) The traditional (old) biotechnology, and (2) The new (modern) biotechnology.

1. Traditional Biotechnology:

It includes the processes that are based on the natural capabilities of microorganisms.

The traditional biotechnology is also called conventional technology which has been used for many centuries.

Curd, vinegar, ghee, wine and beer and other alcoholic beverages, idli, dosa, cheese, paneer and some other foods have been produced using traditional biotechnology.

In Indian Ayurveda, production of 'Asva', 'Arista', etc. is done through traditional biotechnology.

According to some people, traditional biotechnology, is therefore, called an art rather than a science.

2. Modern Biotechnology:

When highly new and useful traits in crop varieties and animal breeds are created with the help of genetic engineering, it is called modern biotechnology.

It was developed during 1970.

For example, in vitro fertilization leading to a 'test tube baby', synthesizing a gene and using it, developing a DNA vaccine or correcting a defective gene are all a part of modern biotechnology.

Among many, the two main techniques that gave birth to modern biotechnology are as follows:

(i) Genetic Engineering: The techniques which change the chemistry of genetic material (DNA and RNA) to introduce these into host organisms and thus alter the phenotype of the host organism are called genetic engineering (= "Recombinant DNA Technology").

(ii) To maintain the microbial contamination free (Sterile) surrounding in chemical engineering: Due to such type of maintenance only desired microorganisms/cells will be formed in large number for manufacture of biotechnological products such as antibiotics, vaccines, enzymes, hormones, blood clotting factors, etc. It is essential to have complete aseptic conditions.

Concept of Genetic Engineering

Combining DNA from different existing organisms like plants, animals, bacteria etc. results in modified organism with a combination of trait from the parents.

This sharing of DNA information occurs naturally through sexual reproduction and has been exploited in plant and animal breeding for number of years.

However sexual reproduction (recombination) can occur between individuals of same species.

Genetic engineering is the manipulation of prokaryotic as well as eukaryotic DNA.

It involves breakage of a DNA molecule at two desired places to isolate a specific DNA segment and then insert it in another DNA molecule at a desired position.

The product thus obtained is called recombinant DNA and the technique often called genetic engineering.

The cutting of the DNA at specific location became possible by so-called 'molecular scissors', i.e., restriction enzymes.

In chromosomes, there is specific 'ori' site or origin of replication which initiates the replication.

Therefore, for duplication of any foreign DNA in an organism, it should be linked with the 'ori' sites so that the foreign DNA can duplicate and multiply within the organism.

This is called gene cloning and can produce multiple copies of any template DNA.

The construction of the first recombinant DNA emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid (autonomously replicating circular extra-chromosomal DNA) of Salmonella typhimurium.

Stanley Cohen and Herbert Boyer accomplished this in 1972 by isolating the antibiotic resistance gene by cutting out a piece of DNA from a plasmid which was responsible for conferring antibiotic resistance.

These plasmid DNA molecules act as vectors to transfer the piece of DNA attached to it.

As mosquito acts as an insect vector to transfer the malarial parasite into human body.

In the same way, a plasmid can be used as vector to deliver an alien piece of DNA into the host organism.

The linking of antibiotic resistance gene with the plasmid vector became possible with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends.

This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA.

When this DNA is transferred into Escherichia coli, a bacterium closely related to Salmonella, it could replicate using the new host's DNA polymerase enzyme and make multiple copies.

The ability to multiply copies of antibiotic resistance gene in E. coli was called cloning of antibiotic resistance gene in E. coli.

Therefore, there are three basic steps in genetically modifying an organism :

(i) Identification of DNA with desirable genes;

(ii) Introduction of the identified DNA into the host;

(iii) Maintenance of introduced DNA in the host and transfer of the DNA to its progeny .