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CHAPTER 12

BIOTECHNOLOGY AND ITS
APPLICATIONS
12
...
2 Biotechnological
Applications in
Medicine
12
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4 Ethical Issues

Biotechnology, as you would have learnt from the
previous chapter, essentially deals with industrial scale
production of biopharmaceuticals and biologicals using
genetically modified microbes, fungi, plants and animals
...
Three critical research areas of
biotechnology are:
(i) Providing the best catalyst in the form of improved
organism usually a microbe or pure enzyme
...

Let us now learn how human beings have used
biotechnology to improve the quality of human life,
especially in the field of food production and health
...
1 B IOTECHNOLOGICAL A PPLICATIONS
AGRICULTURE

IN

Let us take a look at the three options that can be thought
for increasing food production
(i) agro-chemical based agriculture;

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(ii) organic agriculture; and
(iii) genetically engineered crop-based agriculture
...
Increased yields
have partly been due to the use of improved crop varieties, but mainly
due to the use of better management practices and use of agrochemicals
(fertilisers and pesticides)
...
Is there
any alternative path that our understanding of genetics can show so that
farmers may obtain maximum yield from their fields? Is there a way to
minimise the use of fertilisers and chemicals so that their harmful effects
on the environment are reduced? Use of genetically modified crops is a
possible solution
...
GM
plants have been useful in many ways
...

(ii) reduced reliance on chemical pesticides (pest-resistant crops)
...

(iv) increased efficiency of mineral usage by plants (this prevents early
exhaustion of fertility of soil)
...
g
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In addition to these uses, GM has been used to create tailor-made
plants to supply alternative resources to industries, in the form of starches,
fuels and pharmaceuticals
...
Bt toxin is produced by a
bacterium called Bacillus thuringiensis (Bt for short)
...
Examples are Bt cotton, Bt corn, rice, tomato, potato and
soyabean etc
...
B
...
These
crystals contain a toxic insecticidal protein
...

The activated toxin binds to the surface of midgut epithelial cells and

BIOTECHNOLOGY AND ITS APPLICATIONS

create pores that cause cell swelling and lysis and eventually cause death
of the insect
...
1)
...
The toxin is coded by a gene
named cry
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(a)

(b)

Figure 12
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A nematode Meloidegyne
incognitia infects the roots of tobacco plants and causes a great reduction
in yield
...
RNAi takes place
in all eukaryotic organisms as a method of cellular defense
...

The source of this complementary RNA could be from an infection by
viruses having RNA genomes or mobile genetic elements (transposons)
that replicate via an RNA intermediate
...
2)
...
These two RNA’s being complementary to each other formed a double
stranded (dsRNA) that initiated RNAi and thus, silenced the specific mRNA

209

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of the nematode
...
The transgenic
plant therefore got itself protected from the parasite (Figure 12
...


(a)

(b)

Figure 12
...


12
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Further, the recombinant therapeutics do not
induce unwanted immunological responses as is common in case of
similar products isolated from non-human sources
...
In India, 12 of these are presently being marketed
...
2
...
What would a diabetic patient do if enough
human-insulin was not available? If you discuss this, you would soon
realise that one would have to isolate and use insulin from other animals
...
Suddenly the whole process becomes
so simple
...

Think about whether insulin can be orally administered to diabetic
people or not
...
Insulin from
an animal source, though caused some patients to
develop allergy or other types of reactions to the foreign
protein
...
3)
...
3 Maturation of
pro-insulin into insulin
called the C peptide
...
The main challenge for production of insulin
using rDNA techniques was getting insulin assembled into a mature form
...
coli to produce insulin chains
...


12
...
2 Gene Therapy
If a person is born with a hereditary disease, can a corrective therapy
be taken for such a disease? Gene therapy is an attempt to do this
...
Here genes
are inserted into a person’s cells and tissues to treat a disease
...

The first clinical gene therapy was given in 1990 to a 4-year old girl
with adenosine deaminase (ADA) deficiency
...
The disorder is caused due to the deletion
of the gene for adenosine deaminase
...
But the problem with both of these approaches that
they are not completely curative
...
A functional ADA cDNA (using a retroviral vector) is then
introduced into these lymphocytes, which are subsequently returned to
the patient
...
However, if
the gene isolate from marrow cells producing ADA is introduced into cells
at early embryonic stages, it could be a permanent cure
...
2
...
Using conventional
methods of diagnosis (serum and urine analysis, etc
...
Recombinant DNA technology, Polymerase Chain Reaction
(PCR) and Enzyme Linked Immuno-sorbent Assay (ELISA) are some of
the techniques that serve the purpose of early diagnosis
...
) is normally suspected
only when the pathogen has produced a disease symptom
...
However,
very low concentration of a bacteria or virus (at a time when the symptoms
of the disease are not yet visible) can be detected by amplification of their
nucleic acid by PCR
...
It is being used to detect mutations in genes in suspected
cancer patients too
...

A single stranded DNA or RNA, tagged with a radioactive molecule
(probe) is allowed to hybridise to its complementary DNA in a clone of
cells followed by detection using autoradiography
...

ELISA is based on the principle of antigen-antibody interaction
...
) or by detecting the antibodies synthesised
against the pathogen
...
3 TRANSGENIC ANIMALS

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Animals that have had their DNA manipulated to possess and express an
extra (foreign) gene are known as transgenic animals
...
Why are these
animals being produced? How can man benefit from such modifications?
Let us try and explore some of the common reasons:
(i) Normal physiology and development: Transgenic animals can
be specifically designed to allow the study of how genes are
regulated, and how they affect the normal functions of the body
and its development, e
...
, study of complex factors involved in growth
such as insulin-like growth factor
...

(ii) Study of disease: Many transgenic animals are designed to increase
our understanding of how genes contribute to the development of

BIOTECHNOLOGY AND ITS APPLICATIONS

disease
...
Today transgenic models exist for many human diseases
such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s
...
Transgenic animals that produce useful
biological products can be created by the introduction of the portion
of DNA (or genes) which codes for a particular product such as
human protein (α-1-antitrypsin) used to treat emphysema
...
In 1997, the first transgenic cow, Rosie, produced
human protein-enriched milk (2
...
The milk
contained the human alpha-lactalbumin and was nutritionally a
more balanced product for human babies than natural cow-milk
...

Transgenic mice are being used to test the safety of the polio vaccine
...

(v) Chemical safety testing: This is known as toxicity/safety testing
...

Transgenic animals are made that carry genes which make them more
sensitive to toxic substances than non-transgenic animals
...
Toxicity
testing in such animals will allow us to obtain results in less time
...
4 ETHICAL ISSUES
The manipulation of living organisms by the human race cannot go on
any further, without regulation
...

Going beyond the morality of such issues, the biological significance
of such things is also important
...

Therefore, the Indian Government has set up organisations such as
GEAC (Genetic Engineering Approval Committee), which will make
decisions regarding the validity of GM research and the safety of
introducing GM-organisms for public services
...


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There is growing public anger that certain companies are being
granted patents for products and technologies that make use of the
genetic materials, plants and other biological resources that have long
been identified, developed and used by farmers and indigenous people
of a specific region/country
...
There are an estimated
200,000 varieties of rice in India alone
...
Basmati rice is distinct for its unique
aroma and flavour and 27 documented varieties of Basmati are grown
in India
...
In 1997, an American
company got patent rights on Basmati rice through the US Patent and
Trademark Office
...
This ‘new’ variety of Basmati had actually
been derived from Indian farmer’s varieties
...
The
patent extends to functional equivalents, implying that other people
selling Basmati rice could be restricted by the patent
...
g
...
If we are not
vigilant and we do not immediately counter these patent applications,
other countries/individuals may encash on our rich legacy and we may
not be able to do anything about it
...

Most of the industrialised nations are rich financially but poor in
biodiversity and traditional knowledge
...
Traditional knowledge related to
bio-resources can be exploited to develop modern applications and can
also be used to save time, effort and expenditure during their
commercialisation
...
Therefore, some nations are developing laws to prevent such
unauthorised exploitation of their bio-resources and traditional
knowledge
...


BIOTECHNOLOGY AND ITS APPLICATIONS

SUMMARY
Biotechnology has given to humans several useful products by using
microbes, plant, animals and their metabolic machinery
...
Genetically
Modified Organisms have been created by using methods other than
natural methods to transfer one or more genes from one organism to
another, generally using techniques such as recombinant DNA
technology
...
There are
several GM crop plants with improved nutritional value of foods and
reduced the reliance on chemical pesticides (pest-resistant crops)
...
Since the recombinant therapeutics
are identical to human proteins, they do not induce unwanted
immunological responses and are free from risk of infection as was
observed in case of similar products isolated from non-human sources
...

Transgenic animals are also used to understand how genes
contribute to the development of a disease by serving as models for
human diseases, such as cancer, cystic fibrosis, rheumatoid arthritis
and Alzheimer’s
...
It does
so by replacing a defective mutant allele with a functional one or
gene targeting which involves gene amplification
...

The current interest in the manipulation of microbes, plants, and
animals has raised serious ethical questions
...


Crystals of Bt toxin produced by some bacteria do not kill the bacteria
themselves because –
(a) bacteria are resistant to the toxin
(b) toxin is immature;
(c)

toxin is inactive;

(d) bacteria encloses toxin in a special sac
...


What are transgenic bacteria? Illustrate using any one example
...


Compare and contrast the advantages and disadvantages of production
of genetically modified crops
...


What are Cry proteins? Name an organism that produce it
...


What is gene therapy? Illustrate using the example of adenosine
deaminase (ADA) deficiency
...


Digrammatically represent the experimental steps in cloning and
expressing an human gene (say the gene for growth hormone) into a
bacterium like E
...


Can you suggest a method to remove oil (hydrocarbon) from seeds based
on your understanding of rDNA technology and chemistry of oil?

8
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9
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Consult internet and find out how to make orally active protein
pharmaceutical

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