About Biotechnology (General Idea)
Here I will discuss a short description about biotechnology. Actually Biotechnology is an applied branch of biology. It has opened new horizons in solving many real problems in different branches of science. To improve human health care, to develop advanced type or crops, to increase the quality and amount of crops, to protect the environment, this technology has opened up doors of immense potentials. In this chapter, we will try to know the facts about this technology briefly.
What is Biotechnology?
The word biotechnology is derived from two words biology and technology. The word biology means special knowledge about organisms and technology means a manner of accomplishing a task specially using technical processes, methods or knowledge. The interrelation between biology and technology is biotechnology. In 1919 Hungarian engineer Karl Ereky first coined the word biotechnology. Through the application of this technology, from a cell of an organism, microorganism or a part of it, any new organism (plant or animal) with new characters is developed or any processed or by-product substance is produced from this organism.
In the advancement of science, biotechnology is not only a new addition. From the dawn of human civilization, man started to apply biotechnology. Man acquired the knowledge of fermentation and brewing about 8000 years ago. In nineteenth century after the discovery of Gregor Johan Mendel’s laws of heredity in the field of genetics, biotechnology started its new advancement. With the continuity of the invention of double helix model of DNA by Watson and Crick in 1953, today’s biotechnology has emerged.
Now a days, tissue culture and genetic engineering from many methods of biotechnology are being used in multidimensional aspects in agriculture and other fields. In order to live well in a healthy and beautiful environment in the present world by ignoring the huge pressure of increasing population, there is no alternative to biotechnology. So the use of biotechnology in every field of life is widespread and massive. By using this technology amount of protein has been increased a lot more than the past. By eating super rice, which is recently invented in this process and rich in iron and beta carotene, we can meet up the want of Vitamin A and iron. Through tissue culture the species of potato, tobacco and banana resistant to virus have been invented. Through biotechnology salinity tolerant and drought resistant species of plants have been invented. Microbes such as bacteria, blue green algae and fungus are being used in producing compost. In order to protect crops from the attack of pests, insecticides bacteria, virus and weeds, microbes and biological agents are being used instead of chemicals and pesticides. An eon making invention is the insulin made by adding human insulin gene to bacteria plasmid and entering them into e-coli bacteria. Interferon is a very precious protein compound which is produced in a very little amount in human body. But this protein is produced so little in human body that it cannot prevent cancer. Russian scientists have been able to produce interferon by using this technology with the help of e-coli bacteria. With the help of this technology, interferon is now being produced commercially and its price is lower than the past. Alexander Fleming when in 1929 invented antibiotic named penicillin, its productivity was quite low. But through this technology, its production has quite gone up. Each cell in human body carries upto 100000 cells. If error is found in any of these cells, disease can attack human body. So far 3500 such disorders in human body have been known. It is hoped that these disorders will be removed through this technology. Besides, identification of viral diseases, cancer detection, production of antibiotic and vaccine are being done through this technology.
Some microbes improve the colour, flavour, nutrition of different crops through their effect on them. This technology is used for producing fermented foods in different industries. Besides there are certain microbes turn certain carbohydrates into alcohol through fermentation. By applying the knowledge of biotechnology, enzymes, extracted from microbes, are being used in different industries such as dairy industries, detergent industries and carbohydrate industries. For enhancing the quantity and quality of different medicines, this technology is applied. By using different microbes, energy is produced from biomass and 60% rich methane gas. Daily waste matters, industrial discharges are being degraded by microbes for the improvement of environment. Rapid afforestation is done by producing large number of saplings of different plants through tissue culture. If bio diversity of any area is destroyed, it has a serious bad effect on the environment of that area. So biotechnology is being used for preservation of biodiversity. For example efforts are being made for rapid propagation of almost extinct plants through tissue culture in order to maintain ecological balance. Different microbes specially bacteria is being used for extracting different elements from the minerals. For example different bacteria are being used for extracting copper and uranium. Some bacteria keep the environment free from pollution by degrading oil and hydrocarbon from the environment. At present for controlling different pests and insecticides, organic pest control system is being used instead of different chemicals. In organic pest control system different microbes are being used with the help of bio technology which plays an important role in preserving the environment.
Tissue culture: Generally, one or a group of cells of the same type is called tissue. The process of growing a tissue on a nourishing and sterilized medium is tissue culture. Tissue culture is comparatively a new branch of botany. In plant tissue culture, any separate part or part of a part like pollen, apical or lateral bud, node, root is cultured on
or in any nourishing and sterilized medium. All the elements for the nutrition and growth of tissue are supplied with the sterilized medium. The part of a plant, being separate with the view of using it in tissue culture, is called ‘explants’. Steps of tissue culture
1. Selection of mother plant:
The healthy, disease resistant plant with high quality is selected for plant tissue culture. 196 Biology
2. Preparation of culture medium:
For the growth of the plant culture, culture media are made by mixing proper amount of essential mineral nutrients, vitamins, phytohormones, sucrose and condensing substance agar to bring the medium to a semisolid state.
3. Establishment of sterilized medium:
Taking the culture medium in a glass container (test tube, conical flask), its opening is usually closed with a cotton plaque. Later in an autoclave machine, keeping it at the temperature of 1210C under 15-lb/sq.-inch pressure for 20 minutes, the medium is sterilized. After the turning of the medium into a cold and semi-solid state, explants are inoculated on it. Then again after closing the mouth or opening the glass container, it is kept in a room with the controlling of light and temperature (25+20 C) for the growth of the explants. In this stage, the tissue placed on the medium through repeated cell division turns directly into a plantlet or callus or a cluster of cells without differentiation.
4. Transfer in root developing medium:
If no root is developed in the plantlets by this time, then after attaining a definite height, shoots are cut and again placed in the root developing medium.
5. Transfer to natural environment or to field level:
After washing with water and putting them outside the room on the tubs, the plantlets are allowed to adapt with the external environment. When the grown up plantlets become fresh and strong, they are once planted in soil in natural environment. Use of tissue culture: By utilizing the tissue culture, now a days in the reproduction of plants and in field of developing new variety, much achievement has been obtained and new horizons have evolved with the vast hopes. From the plant part in a short period of time, innumerable plantlets can be produced with the same characters. Easily disease free and especially free from viruses, plantlets can be produced. It can be free from the limitation of producing plantlets in the specific season. As the facility of producing plantlets in a short period of time in a very conspicuous place, sufficient number of plantlets can be produced and the problem of storing of seeds can be avoided. The attainment of plantlets of those plants which do not reproduce by seeds and they can be speedily transferred in a short period of time in fresh condition. Tissue culture technology is well accredited for the production and conservation of the species about to be extinct. The plants, which do not produce endosperm, can be developed directly by culturing their embryo. The rapid multiplication of the plants, which do not reproduce through sexual reproduction or of which rate of natural reproduction is low, can be done by culturing their embryo. Tissue culture technology is being used for the development of the plants of new characters. French scientist George Morel (1964) proved that it is possible to obtain 40 thousand plantlets from a meristem of the orchid plant named Cymbidium in a year. In natural way, only a limited number of Cymbidium plantlets are produced in a year. In Thailand 50 million plantlets, which are mostly orchids, are produced through tissue culture method in a year. By exporting flowers, the countries like Thailand, Singapore, Malaysia etc. earn every year crores of foreign currency. In 1952 the scientist named Martin obtained disease free Dalia and Potato plant by culturing meristems of them. Nowadays, it has become a regular practice to make some plants free from viral diseases by culturing their meristems, such as potato tubers. In Malaysia the reproduction of palm oil is done through tissue culture. It is possible to Biology 197 obtain 88 crores of plantlets of Garland of Chrysanthemum from a vegetative part of it through tissue culture. By the hybridization in between different species and varieties of Iris, it has become possible to grow more plantlets of it in a year instead of 2/3 years. Commercially the perfume atar is being produced from the suspension of Jasminum using this technology in many different countries. For the operation of heavy engine such as airplane, rocket etc. a kind of oil from sperm whale is required. This sperm whale is gradually becoming extinct. In an alternative way, this oil is being derived only from a plant named jojoba but this plant does not grow anywhere except in a special desert environment (such as, in Arizona, California), and their reproduction is also time consuming. Through tissue culture, not only the reproduction of this plant has become possible but also it has been changed to a level to adapt to the climate of India. In Bangladesh by this time much more successes have been made through tissue culture, such as it has become possible to produce the plantlets of different orchids grown in the country and in other countries. Disease resistant and high yielding plantlets of banana, wood apple, jackfruit have been produced. Garland chrysanthemum, gladiolus, lily, garden carnation etc. flower producing plantlets also have been produced. Cadamba, Jarul, epil epil, bakul, teak, nim etc. timber producing plantlets have been produced. Plantlets of different types of pulses, groundnut, jute have also been produced. It has become possible to produce disease free plantlets and seed microtuber of potato applying tissue culture. Genetic engineering With the view of changing the body of organism in quality by special technique of biotechnology, changing of gene particle in the centre of a cell is called genetic engineering. In other way it can be said, to develop new characters, changing in DNA of any organism is genetic engineering. Genetic engineering is also called recombinant DNA technology. With this technology, the transfer of the desired part of DNA from bacteria to human being, from plant to animal and from animal to plant have become possible. The organism with the new characters is called GMO (genetically modified organism) or GE (genetically engineered) or transgenic.
Stages of the preparation of DNA or GMO
(a) Selection of targetted DNA.
(b) Selection of a carrier so that the transfer of desired segment of DNA becomes possible.
(c) Selection of necessary restriction enzyme (special type of enzyme to cut DNA) to chop the DNA molecule at a particular locus.
(d) Selection of DNA ligase enzyme to join the segments of DNA chopped.
(e) Selection of a host for the replication of the carrier DNA with the segment of desired DNA.
(f) Evaluation of the expression of recombinant DNA prepared with the desired DNA segment.
This technology is being more significantly used by related innovators or investors because in a short period of time very accurately desired characteristic can be transferred by transferring gene through the process of modern biotechnology or genetic engineering.
Genetic engineering is more effective for the development of new crops in comparison with traditional ways of reproduction because transfer of gene is similar or limited to the nearest species through traditional reproduction. But it is possible to transfer directly one or more genes to nearer or distant species through genetic engineering. Moreover, it requires long time to achieve the desired result through traditional way of reproduction. It is possible to obtain plants or animals or microorganisms with desired characteristics in a very short period of time. In case of traditional reproduction, unexpected genes may be transferred with the desired gene and the transfer of desired gene also remains uncertain. In genetic engineering, there is no possibility of transferring unexpected gene and the transfer of desired gene is certain. Traditional reproduction is not controlled by any rules and methods of bio-safety, but in case of genetic engineering it is controlled by internationally accredited rules and methods of bio-safety. Toxicity is not tested in traditional reproduction but test of toxicity is done in genetic engineering. Genetic engineering in developing crops: Genetic engineering or recombinant DNA technology is the most modern biotechnology. The main objective of the technology is to develop organisms with new and advanced characters and by which human beings can be benefited surpassingly. By this time notable successes have already been achieved through this technology.
Harmful insects resistant varieties of crops have been developed, such as Bt corn, Bt cotton, Bt rice (developed in China) etc. These fruits are resistant to the harmful insects under Lepidoptera and Coleoptera orders. For the insertion of bacterial genes named Bacillus thuringiansis into the crops, these genetically modified crops are designated as Bt corn. Using this technology, virus resistant varieties of crop have been developed, for instance
by transferring gene, tomato mosaic virus (ToMV), tobacco mosaic virus (TMV) and tobacco mild green virus (TMGMV) resistant varieties of crop have been developed. The variety of papaya resistant to ring spot virus (PRSV) has also been developed. The research is being carried out for the development of late blight resistant variety of potato by transferring late blight fungus resistant gene. Varieties of corn and cotton tolerant to herbicides have been produced by genetic modification. Scientists have become able to develop herbicides tolerant variety of tomato by transferring herbicides tolerant genes into the tomato from a kind of bacteria. This way herbicides tolerant varieties of soybean, corn, cotton, canola etc. have been produced.
Through genetic engineering more than one trait can be inserted in the same plant. Nowadays, with no trouble this type of transgenic plants is commercially available. For instance, side by side both herbicides tolerant and insect resistant characters have been inserted in corn and cotton. Through genetic change, nutrition value of some crops has been improved. For example, vitamin i.e. beta-carotene gene has been transferred into rice. Taking efforts to add iron in rice is being continued. The attempts are also being made to develop salinity and drought resistant varieties of different crops through genetic modification.
In animals: In livestock, for example transfer of protein C gene has been done to increase protein in cow-milk though still it is in research level. Through genetic modification, genetic changes have been accomplished with the sheep by transferring the growth hormone producing gene from human being to it with the view of increasing its size and meat production. To improve the amount and quality of sheep’s fur, 2 bacterial genes, such as CysE and CysM have been transferred to the genome of sheep.
In healthcare: Hepatitis b-virus vaccine is being produced from yeast through genetic modification. From genetically modified E.coli bacteria and yeast, insulin is being commercially produced for the treatment of the diabetes disease by using the gene, which produces insulin in human body. Human growth hormone and components of the stimulant for accelerated growth of granulocytes macrophage colony are being produced from
genetically modified E.coli bacteria and yeast, and these are respectively being used for dwarfism, viral disease, cancer, AIDS etc.
In improvement of fishing: The areas of petroleum industry and refinery and coal mining are free from pollution because this technology is being used with a view to making the environmental management easy and fast, such as management of industrial wastes and sewage. Dr. M.K. Chakraborty, by performing research on genetic engineering, has developed a variety of Pseudomonas bacteria which is able to disintegrate immediately oil and hydrocarbon in any environment.