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 Johann 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 up
to 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 a forestation 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 especially 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.
 |
Consecutive steps of
tissue culture
|
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.
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 semi-solid 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.
Uses 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 crore 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 obtain 88 crore 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 and
jackfruit have been produced. Garland chrysanthemum, gladiolus, lily, garden
carnation etc. flower producing plantlets also have been produced. Plantlets of
different types of pulses, groundnut and jute have also been produced. It has
become possible to produce disease free plantlets and seed micro tuber of
potato applying tissue culture.
 |
Recombinant DNA technology
|
Genetic engineering
With the view of changing the body of organism in quality by
special technique of biotechnology, changing of gene particle in the center 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
1.
Selection of targeted DNA.
2.
Selection of a carrier so that the transfer of
desired segment of DNA becomes possible.
3.
Selection of necessary restriction enzyme
(special type of enzyme to cut DNA) to chop the DNA molecule at a particular
locus.
4.
Selection of DNA ligase enzyme to join the
segments of DNA chopped.
5.
Selection of a host for the replication of the
carrier DNA with the segment of desired DNA.
6.
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 Coleopteran 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.
These 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 macro-phage 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.
End
0 comments:
Post a Comment