Biology

spp. also have hallucinogenic properterties. Excessive doses of drugs may lead to coma and
Hallucination are unreal perceptions of unreal death due to respiratory failure, heart failure or
object due to the disorder of nervous system. cerebral hemorrhage. A combination of drugs
or their intake along with alcohol generally
Do you know ? results in overdose and even deaths.

Drugs like barbiturates, amphetamine, The most common warning signs of drug
benzo-diazepins, lysergic acid diethylamide and alcohol abuse among youth include drop in
(LSD) are derived from plant Cannabis sativa academic performance, unexplained absence
are used as a medicine. It help the patient in from school/college, lack of interest in personal
contracting insomnia and depression. hygiene, withdrawal, isolation, depression,
fatigue, aggressive and rebellious behaviour,
Addiction and Dependence : deteriorating relationships with family and
Because of the perceived benefits, friends, loss of interest in hobbies, change in
sleeping and eating habits, fluctuations in
drugs are used repeatedly. The most important weight, appetite, etc.
thing, which one fails to realize, is the inherent
addictive nature of alcohol and drugs.Addiction There may even be some far-reaching
is a psychological attachment to certain effects implications of drug/alcohol abuse. If an
–such as euphoria and a temporary feeling of abuser is unable to get money to buy drugs/
well-being –associated with drugs and alcohol. alcohol he/she may turn to crime. At times,
These drive people to take them even when a drug/alcohol addict becomes the cause of
these are not needed, or even when their use mental and financial distress to his/her entire
becomes self-destructive. With repeated use family and friends.
of drugs, the tolerance level of the receptors
present in our body increases. Those who take drugs intravenously (direct
injection into the vein using a needle and
Consequently the receptors respond syringe) are likely to acquire serious infections
only to higher doses of drugs or alcohol leading like HIV and hepatitis B. Use of alcohol during
to greater intake and addiction. However, it adolescence may also have long-term effects
should be clearly borne in mind that use of like loss balance, liver cirrhosis, pancreatitis. It
these drugs even once, can lead to addiction. In could lead to heavy drinking in adulthood.
the absence of any guidance or counselling, the
person gets addicted and becomes dependent Chronic use of drugs and alcohol damages
on their use. Dependence is the tendency of nervous system and liver (cirrhosis). Use of
the body to manifest a characteristic and drugs and alcohol during pregnancy adversely
unpleasant withdrawal syndrome if regular affects the foetus.
dose of drugs/ alcohol is abruptly discontinued.
This is characterized by anxiety, trembling, Another misuse of drugs is that certain
nausea and sweating, which may be relieved sports persons use drugs to enhance
when use is resumed. performance. They (mis)use narcotic
analgesics, anabolic steroids, diuretics and
Effects of Drug/ Alcohol Abuse : certain hormones to increase muscle strength
The immediate adverse effects of drugs and bulk and to promote aggressiveness and
overall improvement in their performance.
and alcohol abuse are manifested in the form Side-effects of the use of anabolic steroids
of reckless behaviour, vandalism and violence. in females include masculinization (features
like males), increased aggressiveness, mood

242

swings, depression, abnormal menstrual cycles, Prevention and Control :
excessive hair growth on the face and body, The age-old adage (i.e. proverb) is
enlargement of clitoris, deepening of voice.
‘prevention is better than cure’ holds true for
In males it includes acne, increased all addictions. It is also true that habits such as
aggressiveness, mood swings, depression, and smoking, taking drug or alcohol are more likely
reduction of size of the testicles, decreased to be taken up at a young age, more during
sperm production, kidney and liver dysfunction, adolescence. It is best to identify the situations
breast enlargement, premature baldness, that push an adolescent towards use of drugs
enlargement of the prostate gland. These effects or alcohol, and to take remedial measures well
may be permanent with prolonged use. in time. In this regard, the parents and the
teachers have a special responsibility.

Use your brain power

Deaddiction may be difficult but not impossible. Collect information about NGOs,
working in the field of deaddiction.

Activity :

1. Identify the name of the plant. Enlist different types of drugs derived/obtained from
the same.

2. Prepare chart of different stages of adolesence mentioning the changes in growth,
sextual development and emotional and social changes.

Stages I II III

Changes Boy Girl Boy Girl Boy Girl

Growth 1.
2.
3.

1.

Sexual development 2.
3.

1.
Emotional and social 2.

3.

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Exercise

Q. 1 Multiple Choice Questions 9. Confirmatory test used for detecting
1. Which of the following is NOT caused
by unsterilized needles? HIV infection is .................
a. Elephantiasis
b. AIDS a. ELISA b. Western blot
c. Malaria
d. Hepatitis B c. Widal test d. Eastern blot

10. Elephantiasis is caused by ............

a. W. bancrofti b. P. vivax

2. Opium derivative is .............. c. Bedbug d. Elephant

a. Codeine b. Caffeine 11. Innate immunity is provided by ...........
a. phagocytes
c. Heroin d. Psilocybin b. antibody
c. T- Lymphocytes
3. The stimulant present in tea is ............. d. B- Lymphocytes

a. tannin b. cocaine

c. caffeine d. crack

4. Which of the following is caused by Q. 2 Very Short Answer Questions
smoking? 1. What is the source of cocaine?
a. Liver cirrhosis 2. Name one disease caused by smoking?
b. Pulmonary tuberculosis 3. Which cells stimulate B-cells to form
c. Emphysema antibodies?
d. Malaria 4. What does the abbreviation AIDS stand
for?
5. An antibody is ............... 5. Name the causative agent of typhoid
a. molecule that binds specifically an fever?
antigen 6. What is Rh factor?
b. WBC which invades bacteria 7. What is schizont?
c. secretion of mammalian RBC 8. Name the addicting component found in
d. cellular component of blood tobacco.
9. Name the pathogen causing Malaria.
6. The antiviral proteins released by a 10. Name the vector of Filariasis.
11. Give the name of the causative agent of
virus-infected cell are called ............ ringworm.
12. Define health.
a. histamines b. interferons
Q. 3 Short Answer Questions:
c. pyrogens d. allergens 1. What are acquired diseases?
2. Differentiate between antigen and
7. Both B-cells and T-cells are derived antibody.
from .................... 3. Name the infective stage of Plasmodium.
a. lymph nodes Give any two symptoms of malaria.
b. thymus glands 4. Explain the mode of infection and cause
c. liver of elephantiasis.
d. stem cells in bone marrow .5 Why is smoking a bad habit?

8. Which of the following diseases can be

contracted by droplet infection?

a. Malaria b. Chicken pox

c. Pneumonia d. Rabies

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6. What do the abbreviations AIIMS and Q. 5 Match the following.
CMIS denote?
Column I Column II
7. What is a carcinogen? Name one
chemical carcinogen with its target a. AIDS i. Antibody production
tissue.
b. Lysozyme ii. Activation of B-cells
8. Distinguish between active immunity
and passive immunity. c. B-cells iii. Immunoglobulin

d. T-helper cells iv. Tears

e. Antibody v. Immuno deficiency

Q. 4 Short Answer Questions Q. 6 Long Answer Questions
1. Describe the structure of antibody.
1. Differentiate between B-cells and 2. Write a note on Vaccination.
3. What is cancer? Differentiate between
T-cells. bening tumor and malignant tumor.
Name the main five types of cancer.
2. What are the symptoms of malaria? 4. Describe the different type of immunity.
5. Describe the ill –effects of alcoholism on
How does malaria spread? health.
6. In your view, what motivates the
3. Write a short note on AIDS. youngsters to take to alcohol or drugs
and how can this be avoided?
4. Give the symptoms of cancer. 7. Do you think that friends can influence
one to take alcohol/drugs? If yes, how
5. Write a note on antigens on blood cells. may one protect himself/herself from
such an influence?
6. Write a note on antigens-antibody

complex.

7. What are the various public health

measures, which you would suggest as

safeguard against infectious diseases?

8. How does the transmission of each of

the following diseases take place?

a. Amoebiasis b. Malaria

c. Ascariasis d. Pneumonia

9. What measure would you take to prevent

water-borne diseases?

10. Write a short note on typhoid.

Project :
1. Collect information about the, symptoms and preventive measures treatments for Dengue,

Swine flu and Tuberculosis (TB).
2. Browse the information about COVID - 19 with respect to

a. Structure
b. Modes of infection
c. Preventive measures
d. Treatment

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11 Enhancement of Food Production

Can you recall? Do you know ?

1. What are hybrid plants? Primary aim of plant breeding is
2. Different examples of microbes used in to obtain a new crop veriety superior to
the existing type, in all characters. This
household production. purposeful manipulation incorporates various
3. The types or groups of micro-organism objectives. which differ form plant to plant
depending upon its type and the use. Some
that produce antibiotics. objectives are common- like yield, quality,
4. What are biofertilizers? resistance, life cycle span, etc., while some
5. What is the source of silk thread? objectives will differ on the basis of the type
and use of plant.
11.1 Improvement In Food Production :
Food is one of the basic needs as it gives us Plant breeding is a method of altering
the genetic pattern of plants to increase their
energy for everything. It keeps us alive, strong value and utility for human welfare. The plant
and healthy. It can be defined as any thing solid breeding is done to increase crop yield, improve
or liquid, which when swallowed, digested and quality, increase tolerance to environmental
assimilated in the body, keeping us well. It is stresses, make the plants resistant to pathogens
organic, energy rich, non-poisonous, edible and and increase tolerance to insect pest. Green
nourishing substance. Revolution was the result of a sequence of
scientific breakthroughs and developmental
Green plants synthesize their own food activities that successfully fought hunger
through photosynthesis. But animals including by increasing food production. Seeds with
humans can not synthesize their food on their superior quality, use of chemicals - pesticides
own, hence are dependent on plants directly. and fertilizers, and multiple cropping system
supported by the use of modern farm machinery
The famine is responsible for dearth of and proper irrigation system, helped for the
food, besides the rapid and dramatic increase development of high-yielding and disease
in world population over the time. To meet resistant varieties in wheat, rice, maize, etc.
the increasing demand for food, there is need
for improvement of food production, both In fact, plant breeding dates back to about
quantity wise and quality wise (nutritive). 10,000 years ago. The present day crops are the
Plant breeding and animal breeding help us result of domestication and acclimatization.
to increase the food production.
Do you know ?
11.2 Plant breeding :
The improvement or purposeful Different methods of plant breeding
include Introduction, Selection, Hybridization,
manipulation in the heredity of crops and the Mutation breeding, Polyploidy breeding,
production of new superior varieties of existing Molecular plant breeding, Tissue culture,
crop plants, constitute what is called plant rDNA technology, SCP, etc.
breeding. It is, therefore, an applied branch
of botany. It is infact an art and the science
of changing and improving the heredity of
plants. Plant breeding can be carried out by
using the applications of principles of genetics,
taxonomy, physiology, pathology, agriculture,
rDNA technology, etc.

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Know the Scientist : called wide/ distant crosses. Interspecific and
intergeneric hybrids are seldom to occur in the
Dr. Norman E. Borlaug: nature.
An American biologist, who has been
The main steps of the plant breeding
called “Father of the Green Revolution”, program (Hybridization) are as follows :
“Agriculture’s greatest spokesperson” and
“The Man Who Saved a Billion Lives. 1. Collection of Variability :
Dr. Borlaug, a 1970 Nobel Laureate, Wild species and relatives of the cultivated
was honoured for his work in the ‘Green
Revolution,’ saving millions of lives from species having desired traits, should be collected
famine in India, Mexico, and the Middle and preserved. The entire collection having
East. all the diverse alleles (i.e. variations) for all
genes in a given crop, is called germplasm
Dr. M. S. Swaminathan: collection. Variations are useful in the selection.
He has been called the “Father of Green Germplasm conservation can be done in
following ways-
Revolution in India” for his role in introducing • In situ conservation : It can be done with
and further developing high-yielding
varieties of wheat in India. He advocated the help of forests and Natural Reserves.
moving India to sustainable development, • Ex situ conservation : It is done through
especially using environmentally sustainable
agriculture, sustainable food security and the botanical gardens, seed banks, etc.
preservation of biodiversity. He is pioneer in
mutation breeding in India. He developed 2. Evaluation and Selection of Parents :
new varieties of wheat like sonora, NP 165 It is an important and essential step. The
and sarbati.
collected germplasm is evaluated (screened)
A. Hybridization and its technique : to identify plants with desirable characters.
It is the cheif method that offers greater The selected parents must be healthy, vigorous
and should show desirable but complementary
possibilities in the crop improvement than features. The selected parents are selfed for
other methods. The use of this method is the three to four generations to make them pure
only effective means of combining together the or homozygous. It is made sure that only pure
desirable characters of two or more varieties. lines are selected, multiplied and used in the
By this method, one can create new genetic hybridization.
combinations of already existing characters
and new genetic variations. It also exploits and 3. Hybridization :
utilizes hybrid-vigour. The variety showing maximum desirable

Internet my friend features is selected as female (recurrent) parent
and the other one as male parent (donor) which
Try to know more about the hybrid-vigour. lacks good characters found in recurrent parent.

Hybridization can be intravarietal, The pollen grains from anthers of male
intervarietal (between two varieties of the same parent are collected and then artificially dusted
species), interspecific (between two species over stigmas of emasculated flowers of female
of the same genus) and intergeneric (between parent. Pollination is followed by seed and fruit
two genera of the same family). As parental formation in due course. The seed, thus obtained
plants are distantly related, such crosses are also represents the hybrid generation.

The hybrid F1 progeny is selected and
evaluated forthe desired combinations of
characters.

247

Chart 11.1 : Steps of Hybridization technique performance is recorded. The selected lines
are then grown for three generations at least in
Collection of variability from germ plasm/ gene natural field, in different agroclimatic zones.
bank Finally variety is released as new variety for use
by the farmers.
Evaluation and selection of parents
Many high yielding, hybrid varieties of rice,
Selection of parent plants with different qualities wheat, sugarcane, millets, developed through
hybridization, have helped farmer community
Selected parents selfed for three to four generations to to attain record agricultural production in India
make them homozygous or true breeding since 1961. This is called green revolution.

Identification of parents as male parent (donor) and Indian Hybrid Crops :
female parent (recurrent)
1. Wheat and Rice :
Collection of pollen grains from the flowers of male In 1960s, wheat and rice production
parent
increased tremendously. Norman E.
Removal of stamens from the flowers of the female Borlaug developed semi-dwarf varieties of
parent (emasculation) wheat. Sonalika and Kalyan Sona are two of
the hybrid wheat varieties, grown in India.
Artificial cross pollination by using pollen grains Semi-dwarf rice varieties were taken from
collected from male parent IR−8 (International Rice Research Institute)
and Taichung native−I (from Taiwan) and
Bagging, tagging of the emasculated flower of female introduced in India. Jaya, Padma and Ratna are
parent the better-yielding, semi-dwarf rice varieties that
were developed later.
Development of fruit and seed representing F1
(hybrid)generation 2. Sugarcane :
• Saccharum barberi is a native of North
Selection and testing of F1 hybrid for combination of
desirable characters India and S. officinarum belongs to South
India.
Field trials for yield (productivity) • S. officinarum has thicker stem and high
sugar contents, but it does not grow well in
Testing and the release of variety North India.
• These two varieties were crossed to get
4. Selection and Testing of Superior the desirable qualities of both (high sugar
Recombinants : content, thicker stem and the ability to grow
in North India). CO -419, 421, 453 are high
The F1 hybrid plants showing superiority yielding and having high sugar contents
over both the parents and having high hybrid- are developed in India at Coimbatore
vigour, are selected. Such hybrids are then selfed (Tamilnadu).
for few generations to make them homozygous
for the said desirable characters till there is a 3. Millets :
state of uniformity, so that the characters will not • Hybrid maize (Ganga-3), Jowar (CO-12),
segeregate further.
and Bajra (Niphad) have been successfully
5. Testing, Release and Commercialization of developed in India.
New Cultivars : • These varieties are high yielding and
resistant to water stress.
The newly selected lines are evaluated
for the productivity and other features like
disease resistance, pest resistance, quality, etc.
Initially, these plants are grown under controlled
conditions of water, fertilizers, etc. and their

248

Plant Breeding for Disease Resistance : variety of rice, NP 836 variety of wheat (rust
Some of the diseases caused in plants are- resistant), Indore-2 variety of cotton (resistant
to bollworm), Regina-II variety of cabbage
Pathogen Plant disease (resistant to bacterial rot), etc.

Fungi Brown rust of wheat
Red rot of sugarcane
Late blight of potato Plant Breeding for Developing a Resistance
to Insect Pest:
Bacteria Black rot of crucifers
Insects being herbivores, incur heavy loss in
Viruses Tobacco mosaic virus the quantity and quality of crops. Resistance in
crops can be developed by following ways :
The basic objective of breeding for disease • Development of morphological characters
resistance is to develop inherent quality in the
plant to prevent the pathogen from causing like hairy leaves in cotton and wheat
the disease. Such varieties of plants are called develop vector resistance from jassids and
disease resistant plants. The basic technique used cereal leaf beetle, respectively.
is the same as for normal hybridization process. • Solid stem in wheat leads to resistance to
stem borers.
Some disease resistant plants developed are : • Biochemical characters provide resistance
to insects and pests. For example, the high
Crop Variety Resistant to aspartic acid, and low nitrogen and sugar
content in maize, lead to resistance against
Disease stem borers.
• The nectar-less cotton having smooth leaves
Wheat Himgiri Leaf and stripe develop resistance against bollworms.

rust, hill bunt Some pest-resistant varieties are-

Brassica Pusa Swarnim White rust

Cauliflower Pusa Shubra Black rot and

Curl blight black

rot

Chilli Pusa Chilli mosaic

Sadabahar virus, Tobacco Crop Variety Insect pest

mosaic virus and Brassica Pusa Gaurav Aphids

leaf curl Flat bean Pusa sem 2 Jassids, aphids and
Pusa sem 3 fruit borer
B. Mutation Breeding :
Mutation is sudden heritable change in Okra Pusa Sawani, Shoot and fruit borer
Pusa A-4
the genotype, caused naturally. It can also be
induced by application of chemical mutagens. 11.3 Tissue culture :
Natural (physical) mutagens are : High tem-
perature, high concentration of CO2, X rays, It is actually a collection of different
UV rays. techniques. It is infact, emerged as a technique
of plant biotechnology. Here, isolated cells,
Chemical mutagens are : Nitrous acid, EMS tissues, organs are grown ‘in vitro’ on a solid/
(Ethyl- Methyl- Sulphonate), Mustard gas, liquid nutrient medium, under aseptic and
Colchicine, etc. controlled conditions of light, humidity and
tempreature, for achieving different objectives.
Seedlings or seeds are irradiated by CO- The part of plant used in tissue culture is called
60, exposed to UV bulbs, X ray machines, etc. explant.

Mutagens cause gene mutations and Plant tissue culture is based on principle
chromosomal aberrations. The treated of Totipotency which is an inherent ability of
seedlings are then screened for resistance to living plant cell to grow, divide, redivide and
diseases/ pests, high yield, etc. e.g. Jagannath give rise to a whole plant. Haberlandt (1902)

249

for the first time conceived this idea and Other conditions maintained are :
developed the concept of in vitro cell culture Temperature - 180C to 200C, pH of nutrient
(plant morphogenesis). medium 5 to 5.8 and aeration particularly for
suspension culture.
The plant tissue culture medium contains all
essential minerals, sources for carbohydrates, In callus culture the solid medium is used.
proteins and fats, water, growth hormones, The development and organisation of tissue
vitamins and agar (for callus culture). The is lost. Hence, the cells of explant, divide and
most commonly preferred medium for tissue redivide to form a mass of undifferentiated cells,
culture is MS (Murashige and Skoog) medium. called callus. It is maintained on solid medium.
Callus can be induced to form organs like root
Based on the nature of explant : There are (rhizogenesis) and shoot (caulogenesis) and
three types viz, cell culture, organ culture and thus the plantlet. No shaker (agitator) is needed.
embryo culture.
In suspension culture small groups of
Based on the type of in vitro growth : There cells or a single cell are used as explant in the
are two tyes viz. Callus culture (solid medium) liquid medium. The liquid medium is constantly
and Suspension culture (liquid medium). agitated by using shakers (agitators) so that
there is constant mixing of medium and the
Maintenance of aseptic conditions : explant.
Aseptic condition is essential so as to avoid
contamination by other harmful micro- Both the callus and suspension cultures die
organisms. It is accomplished by sterilization in due course of time. Therefore, subculturing
of : glass ware (use of detergents, hot air is neccessary for continuation of the technique.
oven), nutrient medium (by autoclave under
constant pressure of 15 lb/sq inch for continous Micropropagation (Clonal Propagation) :
20 minutes), Explant (by treatment of 20% Organogenesis via shoots is considered
ethyl alcohol and 0.1% HgCl2), Inoculation
chamber (Laminar air flow) - by using UV as one of the most widely used commercial
ray tube for 1 hour before performing actual method of regeneration of plant.
inoculation of explant on the sterilized nutrient
medium. Micropropagation is also known as
clonal propagation. It is the only process
adopted by Indian plant biotechnologists in

Callus

Shoot

Explant

Mother plant Root Multiple
Organogenesis plants

Hardening

Fig. 11.2 : Steps in plant tissue culture (callus culture)

250

Do you know ? Advantages of microporpagation:

Applications of tissue culture : 1. It helps in rapid multiplication of plants.
There are various application of tissue culture 2. A large number of plantlets are obtained
in forestry, agriculture, horticulture, genetic
enginearing, physiology, etc. The different within a short period and from a small
applications of tissue culture include - space.
Production of disease free plants and haploid 3. Plants are obtained throughout the year
plantlets, micropropagation, production of under controlled conditions, independent
secondary metabolites, protoplast culture, of seasons.
culture of rare plants, somaclonal variations 4. Genetically similar plants (clones) are
production of stress resistant plants, etc. produced (formed) by this method.
Therefore desirable characters (genotype)
different industries, mainly for the commercial and desired sex of superior variety are
production of ornamental plants like orchids, kept constant for many generations.
Chrysanthemum, Eucalyptus, etc. and fruit 5. The rare plant and endangered species
plants like banana, grapes, Citrus, etc. are multiplied by this method and such
plants are saved.

Chart 11.3 : Flow chart for tissue culture technique.
Cleaning of glass ware, sterilization of glass ware and instruments in an oven/ autoclave

Selection and preparation of nutrient medium- MS medium with known concentrations and
proportions of different components.

Sterilization of medium in an autoclave for continuous 20 minutes under constant pressure
of 15/ lb/ inch2.

Preparation of plant material (explant) includes isolation of explant followed by surface
sterilization and rinsing with water. Explant is obtained from the growing stock plant.

Inoculation of the explant in the culture flask containing sterilized nutrient medium.
Inoculation is done in the laminar air flow cabinet unit.

Incubation of the inoculated explant. Here cells of explant grow, proliferate to form callus,
within 2-3 weeks.

Sub culturing of the callus (if callus is to be maintained for longer period, callus is divided
into 3-4 segments and then transferred to fresh culture medium).

Organogenesis - Initiation of rooting and shooting, that eventually leads to plantlet
formation.

Hardening - Plantlets are transferred to polythene bags containing sterilized soil and kept at
low light and high humid conditions for suitable period of time.

Transferred to field
251

6. With the help of somatic hybrids (cybrids), The microorganisms utilize the carbon
we are able to obtain new variety in short and nitrogen present in these materials and
time span. convert them into high-quality proteins that
can be used as a supplement, in both human
Do you know ? and animal feed. Besides proteins, SCP is also
rich in vitamins, vitamin B complex, minerals
High yielding varities of Banana viz. and fats. The single-cell proteins can be readily
‘Shrimati’, ‘Basarai’ and G- 9 are mostly used as fodder for achieving fattening of calves,
used in Maharashtra. pigs, in breeding fish and even in poultry and
cattle farmimg. The microorganisms used for
11.4 Single cell protein (SCP) : the production of SCP are as follows :

By 2050, the world would need to produce Fungi : Aspergillus niger, Trichoderma viride
1,250 million tonnes of meat and dairy products Yeast : Saccharomyces cerevisiae, Candida
per year, to meet global demand for animal-
derived protein at current consumption levels. utilis
However, growing demand for protein will Algae : Spirulina spp, Chlorella pyrenoidosa
not be met sustainably by increasing meat and Bacteria : Methylophilus methylotrophus,
dairy production because of the low efficiency
of converting feed to meat and dairy products. Bacillus megasterium.

More over, human population in Advantages of Single-Cell Protein :
underdeveloped and even in the developing • Microorganisms have a high rate of
countriesis suffereingfromproteinmalnutrition,
resulting into variety of nutritional diseases. multiplication that means a large
To fight with this, efforts are undertaken by quantity of biomass can be produced in a
conventional methods to increase the food yield comparatively short duration.
by different methods of crop improvement, • The microbes can be easily genetically
use of biofertilizers, biopesticides, chemical modified to vary the amino acid
fertilizers and high yielding varieties (green composition. They have high protein
revolution). The efforts in other direction are contents- 43% to 85% (W/W basis).
also undertaken in nonconventional way. • A broad variety of raw materials, including
One such way is production of SCP- single waste materials, can be used as a substrate
cell proteins. Improtance of SCP was realised for SCP. This also helps in decreasing the
during World War I. number of pollutants.
• SCP serves as a good source of vitamins,
Single-cell protein refers to the crude, or amino acids, minerals, crude fibres, etc.
a refined edible protein, extracted from pure 11.5 Biofortification
microbial cultures or from dead or dried cell
biomass. It is a method in which crops are breed
(produced) for having higher levels of vitamins,
Microorganisms like algae, fungi, yeast, minerals and fats (i.e. better nutritive value).
and bacteria have very high protein content in Due to this, problem of malnutrition can be
their biomass. These microbes can be grown overcome. Following objectives were considered
using inexpensive substrates like agricultural for the breeding program :
waste viz. wood shavings, sawdust, corn cobs,
paraffin, N-alkanes, sugarcane molasses, even • Protein content and quality
human and animal wastes. • Oil content and quality
• Vitamin content
• Micronutrient content and quality

252

Biofortification can be achieved through Management of farms and farm animals :
conventional selective- breeding practices and Farm management starts from selection of
also through r-DNA technology. It focusses on
making plant food more nutritive as plants grow high yielding breeds, their food requirements,
or develop. supply of adequate nutritional sources,
cleanliness of the environment and maintenance
Some examples of biofortification : of health. Management of farm animals includes
• Fortified Maize having twice the amount veterinary supervision, vaccination, high
yielding cross breed development, production
of amino acids- lysine and tryptophan. and preservation of products, distribution and
• Wheat -Atlas 66 has a high protein content marketing.

and Iron-fortified rice has 5 times more A. Animal breeding :
iron, are developed. Breeding of animals is an important aspect
• Vegetable crops like carrot and spinach
have more vitamin A and minerals. of animal husbandry. Animal breeding aims at
• Vitamin C enriched bitter gourd, tomato increasing the yield of animals and improving
have been developed by IARI. the desirable qualities of the products.

11.6 Animal husbandry : Breed:
Animal husbandry is an agricultural A group of animals related by descent

practice of breeding and raising livestock. It is and similar in most characters like general
not only a skill of farmers but also is as much appearance, features, size, configuration, etc.,
a science, as it is an art. are said to belong to a breed.

Animal husbandry deals with care and Animal breeding is done for getting
breeding of livestock like buffaloes, cows, improved breeds with desirable qualities of
pigs, horses, cattles, sheeps, camels, goats, etc. product and to increase yield of animals,
which are useful to humans. It also includes Desirable characters such as increased
poultry farming, fish farming, bee keeping, production of milk, quality of product, quality
sericulture, lac culture, etc. Animals like honey of meat or maximum yield of eggs per year
bees, silk worms, prawns, crabs, birds, fishes, etc., are necessarily achieved through animal
pigs, cattles, sheeps and camels have been used breeding.
by humans for the products like milk, eggs,
meat, wool, honey, silk, etc. Can you tell?

During the conventional practices of Find out the name of common breeds
animal breeding, just taking care is not enough of cattle and poultry in the farms, found in
to give maximum yield. Although India and your area.
china have 70% of world livestock population,
surprisingly the productivity serves only 25% Breeding can be of two main types -
of the world farm produce. inbreeding and outbreeding :
a. Inbreeding : It involves breeding of closely
So professional approach is needed to related individuals for 4 to 6 generations.
boost the production. It requires management Inbreeding increases homozygosity. By
procedures, new technologies to be employed inbreeding, pure lines of animals can
in various farm system to achieve improvement be obtained. Inbreeding is helpful in the
in quality and productivity. Industrial principles elimination of harmful recessive genes and for
of production, processing and marketing are to the accumulation of superior genes. Inbreeding
be employed. has the demerit that it usually reduces the
fertility and productivity.

253

b. Outbreeding: It involves breeding of quality meat yielding bulls have been found to
unrelated animals. The animals may be of the be successful, to increase herd size in a short
same breed but having no common ancestors period.
for 4 to 6 generations.
B. Dairy farm management :
Outcrossing involves breeding between the Dairy industry involves production,
animals of different species. It is also known as
interspecific hybridization. Outcrossing helps processing and distribution of milk and
to remove the inbreeding depression. milk products. Milk is a valuable food stuff
universally consumed by human beings. Milk
Crossbreeding involves the breeding yield mainly depends on the quality of breeds in
of superior male of one breed with superior the farm. Selection of good breeds having high
female of another breed. By cross-breeding, yielding potential under the climatic conditions
new animal breeds of desirable characters are of inhabiting area, and disease resistance is the
developed. e.g. Hisardale is a new breed of basic requirement. In India, cows and buffaloes
sheep developed from crossing of Bikaneri ewe are mainly used for dairy farms. Sahiwal,
and Marino rams in Punjab. Sindhi, Gir are Indian breeds and Jersy, Brown
Swiss, Holstein are exotic breeds, which are
Interspecific hybridization involves used in dairy farming. Buffaloes are restricted
breeding of animals of two different but related to some part of Asia only.
species. It result in the formation (production)
of animals with desirable characters from both In India, six breeds occur viz, Jaffarabadi,
the parents. But such breeding is not always Mehsana, Murrah, Nagpuri, Nili, Surati,
successful e.g. Mule is a breed obtained from which are all good milk producers. Cattles
horse and donkey. have to be well looked after. Quality and
quantity of fodder in proper ratio, should be
Artificial insemination technique given. Silage made from legumes and grasses,
involves controlled breeding experiments. maize and jowar, makes good feed. Silage
Semen from selected superior males is collected is supplemented with oil cakes, minerals,
and preserved in frozen state or injected into vitamins and salts. Cleanliness and hygiene of
the genital tract immediately. It is useful to the cattles and handlers is of more importance
overcome problem of normal mating and while milking, storage and transport of milk
convenience of transportation. and milk products. In recent years, much of
these processes are mechanised, which reduce
Multiple Ovulation Embryo Transfer the chance of direct contact with the product.
(MOET) involves the technology which The shed must be cleaned daily. It should be
provides the chances of successful production spacious with adequate facilities for feeding,
of hybrids. In this method, cow is administered watering and lighting.
with FSH like hormone, to induce follicular
maturation and then the super ovulation is Do you know ?
brought about. In each cycle, 6 to 8 eggs mature
simultaneously. The cow is either mated with Regular visit of veterinary doctor to
an elite bull or artificially inseminated. The dairy farm is mandatory, why ?
blastocysts at 8 to 32 cell stage are recovered
non-surgically and transferred to surrogate Milk processing, marketing and
mothers. This technology is successfully used distribution, play an important role in dairy
in cattles, sheeps, rabbits, buffaloes, etc. industry. Variety of milk product like curd,
High milk yielding breeds of female and high cream, butter, ghee, condensed milk, khoa,

254

cheese must be prepared from extra milk and on i. Viral diseases like Ranikhet, Bronchitis,
demand. An additional income can be obtained Avian influenza (bird flu), etc. Few years
in the cattle farms from cow dung, manure, fuel back, bird flu have seriously influenced poultry
cakes and gobar gas for cooking and lighting. farming and human infection too.
ii. Bacterial diseases mainly includes
C. Poultry farm management : Pullorum, Cholera, Typhoid, TB, CRD (chronic
Poultry includes number of bird species respiratory disease), Enteritis, etc.
iii. Fungal diseases are Aspergillosis, Favus
such as chicken, ducks, turkey, and fowls which and Thrush.
are domesticated for their eggs and meat. iv. Parasitic diseases include lice infection,
round worm, caecal worm infections, etc.
Can you tell? v. Protozoan diseases e.g. Coccidiosis is a
protozoan disease.
1. What is layer ? D. Apiculture or bee keeping :
2. What is broiler ?
Apiculture or bee keeping deals with an
Allied professions to poultry include artificial rearing of honey bees to obtain bee
processing of eggs and meat, marketing products like honey, wax, pollens, bee venom,
of poultry products, compounding and propolis (bee glue) and royal jelly as well as
sale of poultry feed, poultry equipment, pollinating agents for crop plants.
pharmaceuticals, feed additives, etc.
Fig. 11.4 : Bee hive
Selection of proper and disease free breed, Bee keeping is an ancient cottage industry.
suitable and safe farm condition, proper Honey is a food of high nutritive value and
feed and water, hygiene and health care, also finds uses in the indigenous system of
are important requirements for poultry farm medicines.
Management. On the basis of their origin,
different types of poultry breeds are : American Can you tell?
breeds Plymouth Rock, New Hampshire, Why are honey bees called as best
Rhode Island Red; Asiatic breeds are Brahma, pollinators?
Cochin and Langshan; Mediterranean breeds The four species of honey bees commonly
are Leg horn, Minorca; English breeds include found in India are Apis dorsata (rock bee or
Australorp; Indian breeds are Chittagong, wild bee), Apis florea (little bee), Apis mellifera
Aseel, Brahma, and Kadaknath. (European bee) and Apis indica (Indian bee).

Leghorn is best layer (for eggs) while
Playmouth rock, Rhode Island Red, Aseel,
Brahma and Kadaknath, are preferred as
broilers (for meat).

Management of layers, requires purchase
of high yielding chicken, well ventilated
farms, proper feed, debeaking, lighting,
waterer, sanitation, culling and vaccination.
Management of broilers requires selection
of breed, housing, temperature, ventilation,
lighting, floor space and broiler feed. Different
types of poultry diseases are:

255

Knowledge enhancer : seasons, handling and collection of honey, bee
For bee keeping, Apis mellifera and Apis wax and other products. Periodic inspection for
cleanliness of hive boxes, activity of bees and
indica are the suitable species, hence they queen, condition of brood, provision of water,
are known as domesticated species. is very much necessary.

Many Indian crop fields need the services
of honey bees as the pollinators. Bee keeping in
the crop field of sunflower, mustard, safflower,
chilly, cabbage, cucumber, legumes, fruits like
apple, mango, citrus, etc. help in increasing
the productivity of honey as well as crops
tremendously.

Worker Queen Drone E. Fishery :
Fishery is a branch of applied biology
Fig. 11.5 : Honey bee (Apis mellifera)
which deals with the catching, processing, fish
Polymorphism in honey bee : farming and marketing of fish, and other useful
Bee keeping is practiced in the areas aquatic animals such as, prawns, lobsters,
oysters, mussels and crabs. Three division of
where sufficient wild shrubs, fruit orchards fishery are- inland fishery, marine fishery and
and cultivated crops are present. Bee keeping estuarine fishery.
requires the equipments like bee hive boxes,
with comb foundation sheets, bee veil, smoker, Inland fishery includes culturing and
bee brush, gloves, gumshoes, uncapping knife, capturing of fish from fresh water bodies like
swarm net, queen excluder, overall hive tool, ponds, lakes, dams and river. Inland aquatic
etc. area of our country covers about 40 to 50 lakh
acres. The common fresh water fish are Labeo
Outer cover with rohita (rohu), Catla (catla), Cirrhina mrigala
crown board (mrigala) and other carps.
Inner cover
Rohu fish Catla fish
Honey super

Frames with
wax foundation

Queen excludor

Hive bodies

Entrance reducer Mrigal fish Common carp

Floor board Grass carp Silver carp

Bottom stand Fig. 11.7 : Fresh water fish forms

Fig. 11.6 : Artificial bee hive
Artificial bee hive :

For successful bee keeping one must be
familiar with the habits of bees, selection
of suitable location, catching and hiving of
swarms, management of hives during different

256

Knowledge enhancer : F. Sericulture :
Fish farming or culturing of edible and
Sericulture is the branch of applied
commercially important fish is only possible
in fresh water bodies. zoology which deals with rearing of silkworm

Marine fishery includes capture of fish and production of silk. Like other farming,
from sea water. Indian coastal line is about
7500 km long. The common marine fish sericulture also involves skill and scientific
are Harpadon (Bombay duck), Sardinella
(sardine), Rastrelliger (mackerel) and knowledge for rearing and development. It
Stromateus (pomphret).
require less investment and can be started in
Can you tell?
small space. It is the oldest business and large
1. Give the names of estuaries found in
Maharashtra and where these estuaries number of families are associated with the
are located.
production of silk in India. Disabled, older
2. Enlist the names of different fish found at
an estuary. persons, handicapped people can successfully

Estuarine fishery includes capture of fish do this job.
from estuary. Estuary is a place where river
meets the sea. e.g. Sunderban area in west Adult female Eggs on mulberry leaf
bengal.
Cocoon Eggs
The common factors for the maintenance Dorsal horn
of fish farm, includes selection of suitable Mature
site, excavation of ponds, requirements of caterpillar
hatchery tank, nursery tank, rearing tank,
stocking tank or ponds, water source, manures, Head
supplementary feed, etc. The culture fishery
may be monoculture (only one species) or Thoracic true Spiracles Adominal pseudo
polyculture (many species) type. legs legs

After catching the fishes, fish spoilage is Fig. 11.8 : Life cycle of silk moth (Mulberry
prevented by different preservation methods silk worm)
like chilling, freezing, freeze drying, sun
drying, smoke drying, salting and canning. In Internet my friend
addition to the source as nutritious food, fish
yield a number of by-products which are of Collect information about life cycle of
commercial value. They are fish oil, fish meal, silk moth.
fertilizers, fish guano, fish glue and isinglass.
These by-products are widely used in paints, The best quality silk called mulberry silk,
soaps, oils, and medicine. Prawns and Lobsters is produced by silkworm Bombyx mori, while
have market value all over the world. Fishery Tussar silk and Eri silk are of inferior quality.
provides good job opportunities and self The quality and quantity of silk depends on the
employment to many people. quality of mulberry leaves on which the larvae
feed.

Rearing, development and looking after
the silkworms, involve skill and labour for
constant watch. A little negligence can spoil
the complete industry. Silkworm larvae may
be infected by protozoans, viruses and fungi.
Besides these, ants, crows, birds, and other
predators are ready to attack these insects,
hence the cages of these larvae must be
managed to prevent predators attack.

257

Fertilization

Egg laying

Adult male End of egg laying

Complete Life Cycle of Lac Insect (Yellow spots indicate
metamorphosis shrinking of female)

Adult female

Male comes Incomplete Hatching
out from anal metamorphosis
(Orange spots indicate
operculum eggs are about to hatch)

Pupa Larvae
(also called as crawlers)

Larvae settling on host

Fig. 11.9 : Life Cycle of Lac Insect

Can you tell? of lac requires an artificial inoculation of plants
which give better and regular supply of good
1. What are the different stages found in life quality and quantity of lac.
cycle of silkworm?
11.7 Microbes in human welfare :
2. Process of cocoon formation. Biotechnology is the applications of
3. Which process is involved in silk
‘Scientific and Engineering principles for the
production from cocoon ? processing of materials by biological agents
to provide goods and service to humans or for
G. Lac culture : human welfare’.
Lac is produced by an insect Trachardia
There are variety of microorganisms like
lacca, which is quite small in size and colonial algae, fungi, bacteria, viruses, protozoans,
in habit. Resin like substance is produced by nematodes, etc. and their products that exhibit
Dermal glands of female lac insect. Insect feeds benificial activities which are used for welfare
on succulent twigs of certain plants like ber, of humans in regard to food, health, industry,
peeple, palas, kusum, babool, etc and secretes agriculture, medicine, biocontrol, etc. These
pink coloured resin, that hardens on coming in organisms are used variously in food and feed
contact with air forming lac. It is produced on technology, industry, waste utilization, energy,
a large scale all over India. etc.

Lac is a complex substance having large Microbes in food preparation :
amount of resin together with sugar, water, The development of biotechnology
minerals and alkaline substances.
occurred in two phases viz, traditional (till
Natural lac is always contaminated. 1971) and modern (after 1970). Traditional
Shellac is pure form of lac obtained by washing biotechnology is based on the fermentation
and filtering. Lac insect is a native of India and principle by using fermenting bacteria. These
our share is 85 % of total lac produced in the were used in the preparation of variety of
world. Products of lac play a vital role in the indigenous fermented food products.
economy of the farmers. Lac is used in bangles,
toys, woodwork, inks, mirrors, etc. Production

258

1. Dosa, Dhokla and Idli: ii. Yoghurt (= yogurt):
The dosa, idli and dhokla are fermented It is produced by curdling milk with

products produced due to activity of bacteria. the help of Streptococcus thermophilus and
They are fermented preparation of rice and Lactobacillus bulgaricus.
black Gram with air borne Leuconostoc and
Streptococcus species of bacteria. CO2 produced iii. Butter Milk:
during fermentation causes puffing up of the The acidulated liquid left after churning of
dough.
butter from curd, is called butter milk.
Can you tell?
iv. Cheese:
Name the microbes used in fermentation The milk is coagulated with lactic acid
of dhokla.
bacteria and the curd formed is filtered to
Find out separate whey. The solid mass is then ripened
with growth of mould that develops flavour in it.
Names of some edible mushrooms Different varieties of cheese are known by their
and poisonous mushrooms. characteristic texture, flavor and taste which
are developed by different specific microbes.
2. Microbes as the Source of Food : The ‘Roquefort and Camembert cheese’ are
Some microbes or their fruiting bodies are ripened by blue-green molds Penicillium
roquefortii and P. camembertii respectively.
directly used as a source of food, as they are The large holes in Swiss cheese are developed
rich in vitamins and proteins. The term “SCP” due to production of a large amount of CO2
or “single cell protein” denotes, dead and dried by a bacterium known as Propionibacterium
cells of microbes like bacteria, algae, molds shermanii.
and yeasts.
Some mushrooms and truffles are directly used 11.8 Role of Microbes in Industrial
as food. They belong to higher fungi. They Production:
produce large, fleshy fruting bodies which are
edible. Fruting bodies are sugar free, fat free During fermentation, variety of products
but rich in proteins, vitamins, minerals and like alcoholic beverages, organic acids,
amino acids. The food in the fruting body is vitamins, growth hormones, enzymes,
low caloried. antibiotics, etc. are produced.

3. Dairy Products: Do you know ?
Lactic acid bacteria (LAB) like
These are actually the secondary
Lactobacillus are added to milk. It ferments metabolites produced during idio phase and
lactose sugar of milk into lactic acid. Lactic are not required by micro-organisms for their
acid causes coagulation and partial digestion of growth. The type of substrate and the type of
milk protein casein. Milk is changed into curd, micro-organism result into the production of
yoghurt and cheese. The starter or inoculum particular secondary metabolites.
used in preparation of milk products actually
contains millions of lactic acid bacteria (LAB). Production on an industrial scale requires
growing microbes in very large vessels, called
i. Curd: fermenters. The main function of a fermenter is
Indian curd is prepared by inoculating milk to provide a controlled environment for growth
of a microorganism, or a defined mixture of
with Lactobacillus acidophilus. It also checks microorganisms, to obtain the desired product.
growth of disease causing microbes.

259

a. Production of Alcoholic Beverages : directly from glucose (e.g. gluconic acid) or
Beverage is a liquid used or prepared for
formed as end products from pyruvate or
drinking e.g. tea, coffee, beer, wine, which
acts as stimulant. Alcoholic beverages are ethanol.
the products of alcoholic fermentation of
specific substrates. Use of microbes in malking Organic acid Microbes used
alcoholic beverages, is known since vedic
period- 5000 to 7000Bc. i. Citric acid Aspergillus niger

Microbes especially yeast have ii. Gluconic acid Aspergillus niger
been used from time immemorial for the
production of beverages like wine, beer, iii. Fumaric acid Rhizopus arrhizus
whiskey, brandy or rum. For this purpose,
the yeast Saccharomyces cerevisiae var. iv. Acetic acid (vinegar) Acetobacter aceti
ellipsoidis (commonly called Brewer’s Yeast)
is used for fermenting malted cereals and fruit The organic acids are further used variously
juices to produce ethanol. Among the e.g. citric acid is used in confectionary, fumaric
beverages, Wine and Beer are produced without acid in resins as wetting agents and gluconic
distillation whereas whiskey, brandy and acid in medicine for solubility of Ca++.
rum are distilled beverages. Tubular tower
fermenter is used for large scale production of c. Production of vitamins:
alcohols.
Vitamins are some organic nitrogenous
Several traditional drinks and foods are
also made through fermentation by yeast. compounds which are capable of performing
Today, a traditional drink of the coastal region,
in South India, is made by fermenting the sugar many life-sustaining functions inside our body.
sap extracted from palm plants and coconut
palm. The famous wine of Goa, traditionally These compounds cannot be synthesized by
known as ‘fenny’ is made by fermenting fleshy
pedicels of cashew fruits. humans (except vitamin D), and therefore they

Alcohol have to be supplied in small amounts in the diet.

Fermenter Microbes are capable of synthesizing the

vitamins and hence they can be successfully used

for the commercial production of many

of the vitamins e.g. thiamine, riboflavin,

pyridoxine, folic acid, pantothenic acid, biotin,

vitamin B12, ascorbic acid, beta-carotene (pro-
vitamin A) and ergosterol (provitamin D).

Vitamins are manufactured by fermentation

using different microbial sources as mentioned

below:

Yeast movement Name of the vitamin Microbial source

i. Vitamin B2 i. Neurospora gossypii
ii. Eremothecium ashbyi

ii. Vitamin B12 Pseudomonas denitrificans
iii. Vitamin C Aspergillus niger

Heat exchanger pump Can you recall?

Fig. 11.10 : Tubular tower fermenter 1. What are antibiotics?
2. Who invented first antibiotic?
b. Production of organic acids:
Microbes are also used for the commercial d. Production of Antibiotics:
Antibiotics are probably the most important
and industrial production of certain organic
acids. These compounds can be produced group of compounds synthesized by industrial

260

microorganisms. Most antibiotics are secondary Enzymes are proteins known as bio-
metabolites. They have therapeutic importance catalysts. Due to their ability to promote
and are used in medical treatment. These are reactions more quickly at body temperature and
produced in small amounts by certain microbes more efficiently. Many microbes synthesize
(like bacteria, fungi and few algae), which and excrete large quantities of enzymes
inhibit growth of other microbial pathogens. into the surrounding medium. Using this
Therefore, they are used in medicine. The feature of these tiny organisms, many enzymes
antibiotics are antibacterial, antifungal, etc. are produced commercially. These enzymes
are Amylase, Cellulase, Protease, Lipase,
Antibiotics have greatly improved our Pectinase, Streptokinase and many others.
capacity to treat deadly diseases such as
plague, whooping cough, diphtheria, leprosy, Several industrial sectors, use enzymes
etc. from microorganisms for specific applications.
In the textile industry, enzymes are able to
Use your brain power improve the quality of the fabrics. In the
Can antibiotics kill viruses? pulp and paper industry, they are involved in
biomechanical pulping and bleaching, in the
Some common antibiotics and their food industry, they are used in the fermentation
microbial sources are listed below : processes for the production of bread and
drinks such as wine and beer, also they
Table 11.11 : Antibiotic producing microbes participate in the extraction of substances, such
as carotenoids and olive oil; lipases are used in
Antibiotic produced Microbial sources detergent industry, because they have superior
cleaning properties, increasing the brightness
Chloromycetin Streptomyces and removing of oil stains; they are also used
Erythromycin venezuelae in cosmetics, animal feed and agricultural
Penicillin industries, among others. Following are the
Streptomycin Streptomyces few examples of enzymes used in industrial
erythreus food processing:
Penicillium

chrysogenum
Streptomyces griseus

Griseofulvin Penicillium Name of the enzyme Microbial source
griseofulvum
Invertase Saccharomyces cerevisiae
Bacitracin Bacillus licheniformis
Pectinase Sclerotinia libertine,
Oxytetracycline / Streptomyces Aspergillus niger
Terramycin aurifaciens
Lipase Candida lipolytica

Can you recall? Cellulase Trichoderma konigii

What are Enzymes? How are they f. Gibberellin production:
classified? Gibberellin is a group of growth hormones

e. Production of Enzymes: mainly produced by higher plants and fungi
In living beings, enzymes play a key role to promote growth by stem elongation. The
first gibberellin was isolated by two Japanese
in metabolic reactions and therefore, these are scientists -Yabuta and Sumiki (1938) from rice
essential for the survival of such beings. seedlings infected with the fungus Gibberella
fujikouri.

261

Extra information: Streptokinase enzyme Do you know ?
(TPA) is produced by the bacterium
Streptococcus spp. It has fibrinolytic effect. The oil eating bacteria can clean up
Hence, it is used as a ‘clot buster’ for clearing crude spills. Collect more information about
blood clots in the blood vessels of patients, these bacteria.
which may cause heart attack.
Composition of Sewage:
Statins produced by the yeast Monascus Sewage consists of approximately 99.5%
purpureus have been produced on commercial
scale. It is a blood-cholesterol lowering agent. to 99.9% water and 0.1 to 0.5% inorganic and
This agent acts as competitive inhibitor organic matter in suspended and soluble form.
of the enzyme responsible for synthesis of Composition of sewage varies depending upon
cholesterol. the type of waste discharged into water from
different industries. e.g. textile, chemicals,
About 15 different types of gibberellins pharmaceuticals, dairy, canning, brewing,
have been isolated. Gibberellins have many meat packing, tannery, oil refineries and meat
practical applications. They are used to induce industries, etc.
parthenocarpy in apple, pear, etc. They are
used in breaking the dormancy of seed and Microorganisms in Sewage:
also in inducing flowering in Long Day Plants Various types of micro-organisms are
(LDP). They are also used to enlarge the size
of grape fruits. also present in sewage. Bacteria, viruses,
fungi, protozoa, nematodes, algae, etc. are
11.9 Microbes in Sewage Treatment: found in sewage. However, their number and
Sewage is a matter carried off in type, fluctuate depending upon the sewage
composition and source of sewage. Raw
drainage. It is a municipal waste containing sewage may contain millions of bacteria per
human excreta, house hold waste, dissolved ml. These include coliforms, fecal Streptococci,
organic matter and even pathogenic microbes anaerobic spore forming bacilli and other types
(bacteria, viruses, protozoans, nematodes and originating in the intestinal tract of humans.
microfungi). It also includes discharged water
from hospital waste, slaughter house waste, Before waste water is made available for
animal dung, etc. Discharge from industrial human use, it has to be treated properly, so as
waste (contains toxic dissolved organic and to remove organic matter, inorganic salts and
inorganic chemicals), tannery, pharmaceutical pathogens as well. Sewage treatment process
waste, etc. also add to sewage. includes four basic steps as follows:

Extra Information : Sewage is also a 1. Preliminary Treatment:
potential source of pathogenic bacteria, The preliminary treatment includes
viruses and protozoa. The causative agents
of dysentery, cholera, typhoid, polio and Screening and Grit Chamber.
infectious hepatitis may occur in sewage. i. Screening : Sewage and waste water
The bacteria from the soil are also present
in the sewage. During the course of sewage contains plenty of suspended, floating
decomposition, initially aerobic and materials, coarse and solid particles along
facultative anaerobic organisms predominate with dissolved substances. The suspended
which are then followed by strict anaerobic objects are filtered and removed. This is
especially methogenic bacteria that produce done in screening chambers. The sewage
methane (CH4) and CO2. is passed through screens or net in the
chambers. Larger suspended or floating
objects are held back in the screening

262

chambers. These have to be removed before mechanically and air is pumped into it. Aerobic
the biological treatment. bacteria grow vigourously and form flocs.
Flocs are the masses of bacteria held together
ii. Grit Chamber : After screening, the filtered by slime and fungal hyphae to form mesh like
sewage is then passed into series of grit masses. These aerobic microbes consume the
chambers. These chambers contain large major part of the organic matter present in
stones (pebbles) and brick-ballast. Coarse the effluent, as they grow. Due to this BOD
particles settle down by gravity. Thus, (Biochemical Oxygen Demand) of the effluent
passage of filtered sewage removes much of is significantly reduced.
the coarse particulate matter.
4. Tertiary treatment:
2. Primary treatment (physical treatment): Once the BOD of waste water is reduced, it
After the preliminary treatment, the
is passed into a settling tank. Here the bacterial
sewage water is pumped into the primary flocs are allowed to sediment. The sediment
sedimentation tank. The sedimentation of is now called activated sludge. Small part of
suspended solid or organic matter occurs in this is passed back in to aeration tank and the
this tank. About 50-70% of the solids settle major part is pumped in to large tanks called
down. There is reduction of about 30-40% (in anaerobic sludge digesters. In these tanks,
number) of coliform organisms. The organic anaerobic bacteria grow and digest the bacteria
matter which is settled down, is called primary and fungi in the sludge. During this anaerobic
sludge which is removed by mechanically digestion, gases such as methane, hydrogen
operated devices. The supernatant (effluent) in sulphide, CO2, etc. are produced. Effluents
the primary sedimentation tank still contains from these plants (digester) after chlorination,
large amount of dissolved organic matter and are released in natural water bodies like rivers
micro-organisms which can then be removed and streams. Chlorination kills pathogenic
by the secondary treatment. bacteria. Digested Sludge is then disposed.

3. Secondary treatment (biological
treatment):
The primary effluent is passed into large

aeration tanks. Here it is constantly agitated

Screening Grit setting Primary treatment

Waste
water

Preliminary treatment to Removal of suspended
remove heavy solids solid particles

Settled sewage

Tertiary treatment

Secondary Aeration Treated
Treatment tank Effluent

(Aerobic bacteria)

Activated sludge Water to recycle

Anaerobic bioreactor Sludge cake
(digester) to dispose

(Anaerobic bacteria)

Fig. 11.12 : Diagrammatic representation of various stages in wastewater treatment

263

11.10 Microbes in Energy Genration : Biogas

Many developing countries are Gas-holder
encouraging for installation of biogas plants
to meet out the requirement of energy. Biogas Dung water (CH4+CO2+.....) Sludge
is used as a domestic as well as industrial
fuel. It is a non-conventional and renewable Charge pit
source of energy and is obtained by microbial
fermentation. Biogas is a mixture of methane Digester
CH4 (50-60%), CO2 (30-40%), H2S (0-3%) and
other gases (CO, N2, H2) in traces. Biogas is Fig. 11.13 : Biogas plant
highly inflamable and is used as a source of
energy. ii. Acidogenesis : In this stage, facultative

Plant wastes, animal wastes, domestic anaerobic, acidogenic bacteria and obligate
wastes, agriculture waste, municipal wastes,
forestry wastes, etc. are commonly used anaerobic organisms, convert simple
for biogas production. Cattle dung is most
commonly employed substrate for biogas organic material into acids like formic
production. It is a rich source of cellulose from
plants. acid, acetic acid, H2 and CO2.

Biogas Production: iii. Methanogenesis :
Most commonly used models of biogas
This is last stage in which anaerobic
plants are KVIC and IARI. The digester used
for biogas production is called Biogas Plant. A Methanogenic bacteria like Methanobacterium,
typical biogas plant using cattle dung as a raw
material, consists of digester and gas holder. Methanococcus convert acetate, H2 and CO2
Digester is made up of concrete bricks and into Methane, CO2 and H2O and other products.
cement, or steel. There is cylindrical gas holder
or gas tank above it to collect gases. Digester 1. 12mol CH3COOH 12CH4 + 12CO2
has a side opening (charge pit) into which raw (acetic acid) methane
material as cow dung is fed. The digester is
partly burried in the soil. 2. 4mol H.COOH CH4 + 3CO2 + 2H2O

Anaerobic digestion involves in three (formic acid)
processes :
3. CO2 + 4H2 CH4 + 2H2O
i. Hydrolysis or solublization : In initial
stage raw material (cattle dung) is mixed Benefits:
with water in equal proportion to make
slurry which is then fed into the digester. 1. It is a cheap, safe and renewable source of
Here anaerobic hydrolytic bacteria (e.g.
Clostridium, Pseudomonas) hydrolyse energy. It can be easily generated, stored
carbohydrates into simple sugars, proteins
into amino acids and lipids into fatty acids. and transported.

2. It can be used for domestic lighting,

cooking, street lighting as well as small

scale industries.

3. It burns with blue flame and without smoke.

4. It helps to improve sanitation of the

surrounding.

5. Itiseco-friendlyanddoesnotcausepollution

and imbalance of the environment. Sludge

which is left over is used as a fertilizer.

264

11.11 Role of Microbes as Biocontrol Agents: Table 11.14 : Microbes and their host

The term biocontrol refers to the use of Pathogen Host
biological methods to control diseases and
pests. The natural method of eliminating and Bacteria: Bacillus Caterpillars,
controlling insects, pests and other disease-
causing agents, is by using their natural, thuringiensis (Bt) cabbage worm,
biological enemies. This is called biocontrol
or biological control. B. papilliae and adult beetle,etc.

The agents which are employed for this B.lentimorbus
are called biocontrol agents. Microbes are one
among them. These microbes include bacteria, Fungi: Aphid crocci,
fungi, viruses and protozoans. Microbes as
biocontrol agents act in three ways, either they Beavueria bassiana, A. unguiculata,
cause the disease to the pest or compete or kill
them. Chemicals, insecticides and pesticides Entomophthora. mealy bugs, mites,
are extremely harmful to human beings and
also pollute our environment. Hence, the use pallidaroseum, and white flies etc
of biocontrol measures will greatly reduce our
dependence on toxic chemicals and pesticides. Zoopthora radicans

Examples of Microbial bio-control : Protozoans: Grasshopper,
Nosema lacustae caterpillars,
i. Bacillus thuringiensis (Bt) is used to get
rid of butterfly, caterpillars where dried crickets
spores of Bacillus thuringiensis are mixed
with water and sprayed onto vulnerable Viruses: Caterpillars and
plants such as Brassicas and fruit trees.
These spores are then eaten by the insect Nucleopolyhedrovirus Gypsy moth, ants,
larvae. In the gut of the larvae, the toxin
(cry protein) is released and the larvae get (NPV) and Granulovirus wasps and beetles.
killed eventually.
(GV)
ii. Trichoderma species are free-living fungi
found in the root ecosystem (rhizosphere). Bioherbicides :
These are effective as biocontrol agents of
several soil borne fungal plant pathogens. Weeds are the unwanted plants that grow
The fungus produces substances like in agricultural fields, ponds, lakes, etc. Weeds
viridin, gliotoxin, gliovirin, etc. that inhibit compete with the main crop in the farm- land for
the other soil borne pathogens attacking water, space, minerals, light, air, etc. and also
root, rhizomes, etc. causing rot disease. act as collateral hosts for several pathogens.

Four groups of biocontrol agents are Microbes are also used as herbicides. Many
known. They are bacteria, fungi, viruses and dicot herbs that grow in the field of cereals as
protozoans. weeds, can be killed by certain microbes. For
examples :
I. Microbial Pesticides and their host :
The corelation is depicted as per the II. Microbial Herbicides and Their Host :

following table : 1. Pathogenic fungi as mycoherbicides:

iii. Phytophthora palmivora - controls milk
weed in orchards.

iv. Alternaria crassa - controls water
hyacinth.

v. Fusarium spp.- control most of the weeds.

2. Bacterial pathogen as herbicides:

i. Pseudomonas spp.- attacks several weeds

ii. Xanthomonas spp.- attacks several weeds

iii. Agrobacterium spp.- attacks several
weeds

265

3. Insects as herbicides : 1. N2 fixing Biofertilizers: The nitrogen
fixing microorganisms which convert
i. Tyrea moth - controls the weed Senecio atmospheric nitrogen into nitrogenous
jacobeac compounds like nitrites and nitrates via
ammonia. Nitrogen fixing microorganisms,
ii. Cactoblastis cactorum - controls cacti also called diazotrophs, are of two types:
weeds. iii.Symbiotic N2 fixing microorganisms:
for eg. Rhizobium, Anabaena, Frankia.
11.12 Role of Microbes as Biofertilizers: These are always associated generally
Fertilizers are nutrients which are with underground parts i.e. roots of
higher plants.
necessary for the growth of plants and thus iv. Free-living or Non- Symbiotic N2 fixing
for the productivity of cultivated plants. Use microorganisms: e.g. Azotobacter,
of fertilizers for increasing productivity is one Nostoc, Clostridium, Beijerinkia,
of the aspects of green revolution. Fertilizers Klebsiella, etc.
are classified as inorganic (chemical) and
organic (biological). Inorganic fertilizers 2. Phosphate solubilizing biofertilizers:
are synthetic where mineral salts of NPK are These are the bacterial species which
mixed in definite proportion and then dusted solubilize the insoluble inorganic
in the field. Non-judicious or excessive use of phosphate compound, such as rock
such fertilizers lead to pollution of soil, air and phosphate. For eg. Pseudomonas striata,
ground water. Soil becomes acidic. Bacillus polymyxa, Agrobacterium,
Microccocus, Aspergillus spp., etc.
Organic fertilizers are biological in origin
and include Farm Yard Manure (FYM), 3. Compost making biofertilizers:
compost and green manure. Use of these Composting is a natural process that
fertilizers increases the fertility of soil. turns organic material into a dark rich
substance called as compost or humus.
Now a days for better and sustainable The composting process is dependent
agricultural production farmers use on microorganisms to break down
biofertilizers and practise organic farming. organic matter into compost. There are
Biofertilizers are mostly N2 fixing, living many types of microorganisms found in
microorganisms which enrich the nutrient active compost such as bacteria, fungi,
quality of soil. They include bacteria, actinobacteria, protozoa and rotifers.
cyanobacteria and fungi.
4. Cyanobacteria as biofertilizers :
Biofertilizers are commercial preparation Many cyanobacteria are aquatic and
of ready-to-use live bacterial or fungal terestrial, free-living or symbiotic, aerobic,
formulations. Their application to plant, soil or photosynthetic, N2 fixing, heterocystous or
composting pits, helps to enrich the soil fertility non-heterocystous forms. e.g. Anabaena,
due to their biological activity. Nostoc, Plectonema, Oscillatoria, etc.
Anabaena, Nostoc and Tolypothrix are
Use of Biofertilizers is cost effective associated with lichens while Anabaena
and eco-friendly. They play a vital role in is associated with plants like Azolla and
maintaining a long term soil fertility and Cycas.
sustainability.

Types of Biofertilizers:

On the basis of nature and function
biofertilizers are divided into following groups-

266

Do you know ? less irrigated lands. The association of VAM
with crop plants helps in conversion of less
Classification of Biofertilizers : productive field into more productive field.
On the basis of nature or group of
Benefits of Mycorrhiza :
organisms, biofertilizers are classified as 1. Selective absorption of P, Zn, Cu, Ca, N,
bacterial fertilizers and fungal fertilizers.
Mn, Br and Fe.
Bacterial fertilizers include eubacteria 2. Enhance water uptake.
and cyanobacteria. On the basis of function, 3. Induce growth by secreting hormones.
bacterial fertilizers are further grouped as 4. Offer protection to host plant from other
nitrogen fixing, phosphate solubalizing and
compost making biofertilizers. Cynobacterial microbes, by secreating antibiotics.
biofertilizers, on the basis of function, are
nitrogen fixing type. Do you know ?

Fungal biofertilizers include Now a days, mycorrhiza are classified
mycorrhizal fungi. On the basis of function, into 8 different types viz, Ectomycorrhizae,
they are classified as ectomycorrhizae and Endomycorrhizae, Ectendomycorrhizae,
endomycorrhizae. Orchidaceous mycorrhizae, Ericoid
mycorrhizae, Arbutoid mycorrhizae,
5. Fungal biofertilizers: Monotrapoid mycorrhizae and Ophioglossoid
Mycorrhiza is a fugus. It forms symbiotic mycorrhizae.

association with the underground parts like Use your brain power
rhizomes and root of higher plants occuring
in thick humid forests. These are discovered Why are healthy root nodules pink in
by Frank (1885). Their are two types viz, colour?
Ectomycorrhizae and Endomycorrhizae. Biofertilizer microorganisms:

I. Ectomycorrhizae: They have well 1. Rhizobium: Rhizobia are rod shaped,
developed mycelium that forms mantle motile, aerobic, gram negative, non
on the outside of the roots. This increases spore forming, nitrogen-fixing bacteria
absorptive surface area of roots and containing Nod genes and Nif genes. They
accelerates uptake of water and nutrients (N, form symbiotic association with roots
P, Ca and K). Due to this the plant vigour, of leguminous plants. They bring about
growth and yield increase. Some hyphae of nodule formation on the roots and multiply
mycorrhizal fungus, penetrate into the root inside the nodule. They fix atmospheric
and forms hartig-net in the intercellular nitrogen into organic forms, which can
spaces of root cortex. be used by plants as nutrients. For eg. R.
leguminosarum is specific to pea. and R.
II. Endomycorrhizae: They grow in between phaseoli to beans.
and within the cortical cells of roots. Fungal
hyphae penetrate the cells and form finely 2. Azotobacter: It is the important and well
branched arbuscules intracellularly and known free living, nitrogen fixing, aerobic,
form vesicles mostly in the intercellular non-photosynthetic, non-nodule forming,
speces of cortical cells. Hence they are called bacterium, intimately associated with roots
Vesiculo Arbuscular Mycorrhizae or VAM. of grasses and certain plants. It is used as a
Now a days they are described as AM fungi. Bio-fertilizer for all non-leguminous plants
The plants with VAM grow luxuriantly in especially rice, cotton, vegetables, etc.

267

Root nodules

Root branch Fig. 11.17 : Azolla

Fig. 11.15 : Root system of Leguminous Photosynthetic zone
plant Anabaena
Cavity
Root nodule
Dorsal lobe
Bacterial colonies
in cortical cells

Root
Xylem

Phloem Fig. 11.18 : L. S. of Azolla leaf showing
filamentous Anabaena
Fig. 11.16 : T. S. of root nodule
In the dorsal lobe, Anabaena filaments
3. Azospirillum: It is free living, aerobic are present in the aerenchyma, which fixes
nitrogen fixing bacterium associated with nitrogen. Azolla can be used as biofertilizer
roots of corn, wheat and jowar. It fixes the in the rice field.
considerable quantity of nitrogen (20-40kg
N/ha) in non – leguminous plants such as Benefits of Biofertilizers :
cereals, millets, cotton, oilseed, etc. 1. Low cost and can be used by marginal

4. Anabaena : It is a genus of multicellular, farmers.
filamentous cyanobacteria that exits as 2. Free from pollution hazards.
plankton. It has ability to fix nitrogen and 3. Increase soil fertility.
also forms symbiotic relationships with 4. BGA as biofertilizers secret growth
certain plants, such as the coralloid roots of
Cycas and Anthoceros thallus. It has some promoting substances, organic acids,
specialized and colourless cells, called proteins and vitamins.
Heterocysts which are the sites for nitrogen 5. Azotobacter supply nitrogen and
fixation. antibiotics in the soil.
6. Biofertilizers increase physico-chemical
5. Azolla: Azolla is a free-floating water fern. properties of soil- like texture, structure,
Azolla plant consist of a floating rhizome pH, water holding capacity of soil by
(stem) with small overlapping bi-lobed providing nutrients and organic matter.
leaves and roots. The leaf shows dorsal and
ventral lobe. Now in our country many biofertilizers
are available in market to reduce the use of
chemical fertilizers and thus, the pollution.

268

Activity :

1. Visit fish market and enlist different types of fresh water and marine water fish
mentioning their local names and scientific names.

Type Local Name Scientific Name Detail Information
1.
2.
3.
4.
5.
6.
7.

2. Label the different parts of the fermenter and mention functions of each part.

269

Exercise

Q. 1 Multiple Choice Questions. 8. MOET technique is used for ............
a. production of hybrids
1. Antibiotic Chloromycetin is obtained b. inbreeding
from ..................... c. outbreeding
a. Streptomyces erythreus d. outcrossing
b. Penicillium chrysogenum
c. Streptomyces venezuelae 9. Mule is the outcome of ..............
d. Streptomyces griseus a. inbreeding
b. artificial insemination
2. Removal of large pieces of floating c. interspecific hybridization
debris, oily substances, etc. during d. outbreeding
sewage treatment is called ................
a. primary treatment Q. 2 Very Short Answer Questions:
b. secondary treatment 1. What does make idlies puffy?
c. final treatment 2. Name any two bacterial biofertilizers.
d. amplification 3. What is the microbial source of vitamin
B12?
3. Which one of the following is free living 4. What is the microbial source of enzyme
bacterial biofertilizer? Invertase?
a. Azotobacter 5. Milk start to coagulate when Lactic
b. Rhizobium Acid Bacteria (LAB) is added to warm
c. Nostoc milk as a starter. Mention any two other
d. Bacillus thuringiensis benefits of LAB.
6. Name the enzyme produced by
4. Most commonly used substrate for Streptococcus bacterium. Explain
importance in medical sciences.
industrial production of beer is ............. 7. What is breed?
8. Define estuary.
a. barley b. wheat 9. What is shellac?

c. corn d. sugarcane molasses Q. 3 Short Answer Questions.
1. Many microbes are used at home during
5. Ethanol is commercially produced preparation of food items. Comment on
through a particular species of .............. such useful ones with examples.
a. Aspergillus 2. What is biogas? Write in brief about the
b. Saccharomyces production process.
c. Clostridium 3. Write a note on biocontrol agents.
d. Trichoderma 4. Name any two enzymes and antibiotics
with their microbial source.
6. One of the free-living anaerobic 5. Write priciples of farm management.
6. Give economic importance of fishery.
nitrogen-fixer is ..................... 7. Enlist the species of honey bee mentioning
their specific uses.
a. Azotobacter b. Beijerinckia

c. Rhodospirillum d. Rhizobium

7. Microorganisms also help in production

of food like .................

a. bread b. alcoholic beverages

c. vegetables d. pulses

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8. What are A, B, C and D in the table given Q. 4 Long Answer Questions.
below : 1. Explain the process of sewage water
treatment before it can be discharged
Types of Name Commercial into natural bodies. Why this treatment is
microbe product essential?
2. Write a note on lac culture.
Fungus A Penicillin 3. Describe various methods of fish
preservation.
Bacterium Acetobacter aceti B 4. Give an account of poultry diseases.
5. Give an account of mutation breeding
C Aspergillus niger Citric acid with examples.
6. Describe briefly various steps of plant
Yeast D Ethanol breeding methods.

Project :
Collect information about
A) Different types of worms/organisms used in sericulture
B) How is silk obtained and isolated
C) Types of silk
D) Job potential of sericulture

271

12 Biotechnology

Can you recall? vinegar, yogurt, cheese making, wine making,
etc. It became an art of kitchen in indian
1. What is Biotechnology? houses. It was more an art than science. Till
2. How do genetically modified organisms that time people did not know as to how exactly
the process occurs and the organisms causing
are produced? this process. The contributions made by several
3. Which are the benefits of Biotechnology? chemists, biochemists and microbiologist,
over the time, could explain the mechanism of
You are already aware of what process and also the nature of microorganisms
biotechnology is. It is the product of interaction causing the process.
between the biological science and technology.
It is infact, an applied branch of biology. The During 1970 a new technique of
term biotechnology was first used by Karl ‘recombinant DNA technology was developed
Ereky in 1919 to describe a process for large and then established by Stanley Cohen and
scale production of pigs. Herbert Boyer in 1973. This technique has
12.1 Biotechnology changed the overall outlook, then. The technique
permits to change/ modify genetic (heritable)
It is defined by different organizations in material for getting new specific products.
different ways. It has been brodly defined as The combination of biology and production
‘the development and utilization of biological technology based on genetic engineering
forms, products or processes for obtaining evolved into modern biotechnology (new
maximum benifits to man and other forms of biotechnology).
life’. According to OECD (Organization for
Economic Cooperation and Development, There are two major features of technology
1981)- ‘It is the application of scientific and that differenciate modern biotechnology from
engineering principles to the processing of classical or old biotechnology viz,
materials by biological agents to provide
goods and service to the human welfare’. i. Capablity of science to change the genetic
It uses scientific priciples of microbiology, material for getting new specific products
genetics biochemistry, chemical engineering, through rDNA technology, polymerase
mathematics, statistics, computers, industrial chain reaction (PCR), microarrays, cell
processes, etc. Biological agent means plants culture and fusion, and bioprocessing.
and animal cells, microorganisms, enzymes or
their products. ii. Ownership of technology and its socio-
political impact.
History of origin of biotechnology is as
old as human civilization. Development of Now the conventional industries,
biotechnology in terms of its growth, occurred pharmaceutical industries, agro industries,
in two phases viz, Traditional biotechnology food industries, etc. are also focussing attention
and Modern biotechnology. to produce biotechnology- based products.

Traditional biotechnology (old 12.2 Principles and Processes of
biotechnology) was primarily based on Biotechnology :
fermentation technology using microorganisms
as in the preparation of curd, ghee, soma, Modern biotechnology is based on two
core techniques viz. genetic engineering and
chemical engineering.

272

Genetic engineering deals with alteration A. Tools and techniques for gene cloning/
of genetic material (DNA and RNA) while rDNA technology :
chemical engineering deals with maintaining
sterile environment for manufacturing Before we venture into a procedure of
variety of useful products including vaccines, gene cloning, let us know briefly, the basic
antibodies, enzymes, organic acids, vitamins, requirements for the technique.
therapeutics, etc. I. Different instruments (devices) :

Genetic engineering is defined as the Macromolecule such as DNA, RNA,
manupulation of genetic material towards a proteins, etc. are synthesized in the living
desired end and in a directed and predetermined cells which vary in their molecular weight,
way, using in vitro process. Manipulation solubility, presence of charges, absorbance
of genes involve repairing of the defective of light, etc. Several techniques are used to
genes or replacing of defective genes by isolate and charaterize the macromolecules.
healthy genes or normal genes; artificially The size of different types of molecules
synthesizing of a totally new gene; transfer varies and therefore their molecular
of genes into a new location or into a new weights also vary. The techniques used
organism; introducing an all together new on the basis of molecular weight, are
gene; manipulation of genes for improvement gel permeation, osmotic pressure, ion
of living organisms; combining of genes from exchange chromatography, spectroscopy,
two organisms, altering the genotype; gene mass spectrometry, electrophoresis, etc.
cloning etc. Therefore, the genetic engineering Electrophoresis is the separation of charged
is alternatively called recombinant DNA molecules, applying an electric field. It
technology or gene cloning. is applied for the separation of DNA,
RNA and proteins. DNA being negatively
Extra information : charged, migrates to anode. Small
John E. Smith (1996) gave definition of fragments of DNA molecules, move faster
and thus separate faster. Use of Agarose gel
genetic engineering as ‘the formation of new electrophoresis, PAGE, SDA PAGE are the
combination of heritable material by the different methods of electrophoresis.
insertion of nucleic acid molecule produced
by whatever means outside the cells, into any Polymerase chain reaction (PCR) :
virus, bacterial plasmid or other vector system Polymerase chain reaction (PCR) is
so as to allow their incorporation into a host
organism in which they do not occur naturally another device used for gene cloning or gene
but in which they are capable of continued multiplication in vitro. It is the amplification of
propagation’. gene of interest, through PCR.

Technique of gene cloning and rDNA In 1985, Kary Mullis made an important
technology : discovery (contribution) in the form of
an extremely powerful technique called
In gene cloning, a gene of known function polymerase chain reaction (PCR). PCR can
can be transferred from its normal location generate a billion copies of the desired segment
into a cell (that of course does not contain it) of DNA or RNA, with high accuracy and
via a suitable vector. The transferred gene is specificity, in a matter of few hours. The process
replicated normally and is handed over to the of PCR is completely automated and involves
next progeny. automatic thermal cycles for denaturation
and renaturation of double stranded DNA.

273

The device required for PCR is called thermal First cycle completes 1 copy of desired gene
cycler.
1
PCR is in vitro amplification of a desired
DNAsegment, which requires : DNA containing Denaturation (90-98 0C)
the desired segment to be amplified, several
molecules of four deoxyribonuclueoside DNA strands
triphosphates (dNTPs), excess of two primer separated
molecules, heat stable DNA polymerase and
appropriate quantities of Mg++ ions. 2

Internet my friend Annealling of primers
(40-60 0C)
Collect the information from internet
about PCR machine. Replicating DNA
strands using

Tag polymerase
(70-75 0C)

3

2 copies of
desired gene
(renaturation)

Second cycle continues to form
4 copies of desired DNA

Mechanism of PCR: Cycle continous to produce
At the start of PCR, the DNA segment, 2n copies of DNA

and excess of two primer molecules, four Fig. 12.1 : DNA replication through
deoxyribonucleosides triphosphates and the polymerase chain reaction.
thermostable DNA polymerase are mixed
together in ‘eppendorf tube’ and the following One cycle takes arround 3 to 4 minutes.
operations are performed sequentially (Figure). To begin second cycle, DNA is again heated
to convert double stranded DNA into single
Step i : The reaction mixture is heated to a strands.
temperature (90–98 oC) to separate two strands
of desired DNA. This is called denaturation. In an automatic thermal cycler, the above
three steps are automatically repeated 20-30
Step ii : The mixture is allowed to cool times. Thus, at the end of ‘n’ cycles 2n copies
(40–60 oC) that permits pairing of the primer of DNA segments, are produed. The machine
to the complementary sequences in DNA. This performs the entire operations automatically
step is called annealing. and precisely.

Step iii : The temperature (70–75 oC) allows Once the desired number of cycles is
thermostable Taq DNA polymerase to use completed, the amplified DNA segment is
single-stranded DNA as template and adds purified by gel electrophoresis. After its
nucleotides. This is called primer extension. It sequencing, the amplified DNA segment can be
takes arround two minutes duration. inserted into a cloning vector. Desired gene can
also be obtained from gene library.

274

II. Biological tools : Thus, restriction enzymes serve as defence
There are three types of biological tools mechanism. The bacteria protect its own DNA
from nucleolytic attack by methylating the bases
used viz, enzymes, cloning vectors (vehicle at susceptible sites, a chemical modification
DNA) and competent host (cloning organisms) that blocks the action of the enzyme.
for transformation with recombinant DNA.
The restriction enzymes are thus the
A. Enzymes : Different enzymes include molecular scissors that are used to recognize
Lysozymes, Nucleases such as exonucleases and cut DNA at specific sequences. The sites
endonucleases, restriction endonucleases, recognized by them, are called recognition
DNA ligases, DNA polymerases, alkaline sequences or recognition sites. Different
phosphatases, reverse transcriptases, etc. restriction enzymes found in different organisms
recognize different nucleotide sequences and
i. Restriction enzymes : therefore cut DNA at different sites. Table
Enzymes that cut the phosphodiester bands encloses list of some restriction endonucleases
and the site at which they cleave DNA.
of polynucleotide chains are called nuclease.
There of two types - exonuclease and Activity :
endonuclease. Exonucleases cut nucleotides
from the ends of DNA strands whereas Find out the biological source of following
endonuclease cut DNA from within. During restriction enzymes and discuss the their
the 1970s, it was found that bacteria contain recognition sequences :
nucleases that would recognize short nucleotide
sequence with duplex DNA and cut. Pst I, Sal I, Taq I, Xer III, Mbo II, Hpa I,
BgII, Kpn I, Not I.
The phosphodiester back bone at highly
specific sites on both strands of duplex, is ii. Recognition sequences :
cut by these enzymes, called restriction The sequences recognized by restriction
endonucleases or simply restriction enzymes.
They were given this name because they enzymes are 4 to 8 nucleotides long and
are used by the bacteria to destroy various characterized by a particular type of internal
viral DNAs that might enter the cell, thereby symmetry. Consider the particular sequence
restricting the potential growth of the virus. recognized by the enzyme EcoRI .

Table 12.2 : Source and recognition sequences (indicated by arrow) of various restriction enzymes:

Restriction Source Recognition sequence Product End
Enzyme (Organism and products
produced
strain)

Alu I Arthobacter luteus 5’ ---A- G- -C -T--- 3’ 5---A-G C-T---3 Blunt ends
3’ ---T- C- -G-A--- 5’ 3---T-C G-A---5

Bam HI Bacillus 5’---G- -G-A-T-C-C---3’ 5---G G-A-T-C-C---3 Sticky ends
amyloliquefaciens H 3’---C-C-T-A-G- -G---5’ 3 ---C-G-T-A-G G---5

EcoRI Escherichia coli 5’ ---G- -A-A-T-T-C---3’ 5---G A-A-T-T-C---3 Sticky ends
3’ ---C-T-T-A-A- -G--- 5’ 3---C-T-T-A-A G---5
Ry13

Hind II H. influenzae Rd 5’--G-T-C- -G-A-C--3’ 5’--G-T-C G-A-C--3’ Blunt ends
3’--C-A-G- -C-T-G--5’ 3’--C-A-G C-T-G--5’

275

3’------- C T T A A G-----5’ host cell. Vectors may be plasmids,
bacteriophages (M13, lambda virus),
5’------- G A A T T C-----3’ cosmid, phagemids, BAC (bacterial
artificial chromosome), YAC (yeast
When one reads the sequence in opposite artificial chromosome), transposons,
direction (3’ to 5’ or 5’ to 3’) it is identical/ baculoviruses and mammalian artificial
same. chromosomes (MACs),. Most commonly
used vectors are plasmid vectors (pBR
DNA showing palandromic sequence 322, pUC, Ti plasmid) and bacteriophages
(lamda phase, M13 phage). Plasmids and
G AAT T C 5’ bacteriophages are most commonly used as
3’ 5’ 3’ vectors.

C T TAA G Restriction enzyme Do you know ?
Eco RI recognitio EcoRI
Smith, Nathan and Arber achieved
sequence the discovery of restriction enzymes. For this
spectacular achievement, they were awarded
5’ 3’ Nobel Prize for physiology and medicine in
1978. Since restriction enzymes have been
3’ 5’ used for genetic manipulation by dissecting,
analyzing and re-configuration the genetic
AAT T C 5’ 3’ information at molecular level.
G
Do you know ?
3’ 5’ G
There are three types of restriction
C T TAA enzyme viz,
Type I - Which fuction simultaniously as
Fig. 12.3 : Mode of action of EcoRl to cleave endonuclease and methylase e.g. E co K.
Type II - Which have separate activities for
DNA cleaving and methylation; they are more
stable and are used in rDNA technology e.g.
A sequence with this type of symmetry E co RI, BgII; these enzymes cut DNA at
is called a palindrome. When the enzyme specific sites within the pallindrome.
EcoRI attacks this palindrome, it breaks each Type III - Which cut DNA at specific non-
strand at the same site in the sequence, which pallindromic sequences e.g. HpaI, MboII.
is indicated by the arrow between the A and G There are thousands of type II R. E. enzymes
residues. are recognized/ discovered.

3’ ---- C T T A A G -------5’ A good vector should have the ability of
5’ ---- G A A T T C -------3’ independent replication so that as the vector
replicates (through ori gene) and large number
Restriction enzymes either cut straight of copies of the DNA insert will be formed.
across the DNA in the region of palindrome to Moreover vector should be able to easily
give blunt ends or cuts producing short, single introduce into host cells.
stranded projections at each end of DNA to
produce, cohesive or sticky ends or staggered
ends.

B. Cloning vectors (vehicle DNA) - Vectors
are DNA molecules that carry a foreign
DNA segment and replicate inside the

276

A vector should have marker genes for transposon, with the new DNA, can still be
antibiotic resistance; must contain unique inserted into the host cell’s chromosomes.
cleavage site in one of the marker genes for A plant cell containing this DNA, can then
restriction enzyme; it should have at least be grown in culture or induced to form a
suitable control elements like promoter, new, transgenic plant.
operator, ribosomal binding sites, etc. The
plasmids obtained naturally do not posses all C. Competent host (cloning organism) used
the characteristics. Hence, they are constructed are usually the bacteria like Bacillus
by inserting gene for antibiotic resistance. haemophilus, Helicobacter pyroli and E.
e.g. pBR 322, pBR 320, pACYC 177 are the coli.
constructed plasmids. pBR 322 is mostly used
in rDNA technology in plants. Mostly E. coli is used for the transformation
with recombinant DNA
i. Plasmid : The plasmids most commonly
used in recombinant DNA technology are 12.3 Methodology for rDNA technology :
those that replicate in E. coli. Investigators
have engineered these plasmids to optimize The steps involved in gene cloning are as
their use as vectors in DNA cloning. follows :

Polylinker ori a. Isolation of DNA (gene) from the donor
organism :
HindIII Region into which
Sphl foreign DNA can i. The desire gene to be cloned has to be
obtained from the source organism (donor).
Pstl be inserted Initially the cells of the donor organism are
sheared with the blender and treated with
Sall ampr suitable detergent. Genetic material from
Xbal the donor is removed isolated and purified
BamHl by using several techniques. Isolated DNA
Smal can be spooled on to a glass rod.
Kpnl
ii. Isolated purified DNA is then cleaved
Sacl by using restriction enzymes particularly
EcoRl Restriction Endonucleases (RE). These
enzymes cleave DNA at specific sites,
Fig. 12.4 : Plasmid cloning vector showing called restriction sites and break the DNA
a replication origin (ori), a drug resistance into fragments. There are several types of
gene (ampr ) and a region in which foreign restriction endonucleases. Cleaved DNA
fragments have cohesive, sticky, staggered
DNA can be inserted. ends or blunt ends.

ii. Plasmid vectors for plants : An important From cleaved DNA fragments, a fragment
vector for carrying new DNA into many containing desired gene is isolated and selected
types of plants is a plasmid that is found in for cloning. This is now called foreign DNA
Agrobacterium tumefaciens. This bacterium or passanger DNA. A desired gene can also
lives in the soil and causes a plant disease be obtained directly from genomic library or
called crown gall, which is characterized cDNA library.
by the presence of over- growths, or tumors,
in the plant. A. tumefaciens contains a
plasmid called Ti (for tumor-inducing). The
Ti plasmid contains a transposon, called T
DNA, which inserts copies of itself into the
chromosomes of infected plant cells. The

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Donor cell Vector
(a plasmid or bacteriophage)
Do you know ?
A Vector
Gene library is a collection of different Isolation of
DNA sequences from an organism where desired DNA
each sequence has been cloned into a vector
for ease fo purification, storage and analysis. Target Enzymatic Vector DNA
There are two types of gene libraries on the DNA fragmentation
basis of the source of DNA used.
• Genomic library : It is a collection of by restriction

clones that represent the complete genome B enzyme
of an organism. The genomic library of C Joining of target DNA and
prokaryotes can be constructed by using
plasmid vector. It is because prokaryotic Target cloning vector by DNA ligase
genome does not contain repeatitive
DNA. DNA rDNA Introduction into a bacterial
• cDNA library : It represents the library D
of eukaryotic organisms only. DNA is host cell (Transformation
produced from isolated mRNA by reverse
transcription. The DNA so made is called Host bacteria E viral infection)
complementary DNA (cDNA). The
library is called cDNA library. Eukaryotic Transformed host
DNA genome contains introns, regulatary
genes and repeatitive DNA. Hence, the cell containing rDNA
establishment of genomic library in
eukaryotes is not meaningful molecule
F Identification and
b. Insertion of desired foreign gene into a
cloning vector (vehicle DNA) : selection Amplification
The foreign DNA or passanger DNA is now
G Cell multiplication
inserted into a cloning vector or vehicle DNA. Protein production from
The most commonly used cloning vectors are cloned gene
plasmids of bacteria and the bacteriophage
viruses like lamda phage and M13. The most Protein encoded by
commonly used plasmid is pBR 322. insert DNA

Plasmids are isolated from the vector Protein harvesting
organims i.e. bacterium. By using same RE
(which is used in the isolation of the desired Fig. 12.5 : Outline of the process of
gene from the donor), plasmid i.e. vector DNA recombinant DNA technology
is cleaved.
c. Transfer of rDNA into suitable competent
Now by using enzyme DNA ligase, foreign host or cloning organism :
DNA is inserted/ integrated into the vector Finally the recombinant DNA is now
DNA. The combination of vector DNA and
foreign DNA is now called Recombinant introduced i.e. transferred for expression into
DNA or Chimeric DNA and the technology is a competent host cell of the suitable cloning
reffered to as rDNA technology. organism which is usually a bacterium.
Host cell takes up naked rDNA by process
of ‘transformation’ and incorporates into
its own chromosomal DNA which finally
expresses the trait controlled by passenger
DNA. The transfer of rDNA into a bacterial
cell is assisted by divalent Ca++. The cloning
organisms used in plant biotechnology are
E.coli and Agrobacterium tumifaciens. The
host/ competent cell which has taken up rDNA
is now called transformed cell.

Foreign DNA can also be transferred
directly into the naked cell or protoplast of the
competent host cell, without using vector. This

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is done by using techniques like electroporation, f. Expression of the gene to obtain the desired
microinjection, lipofection, shot gun, product:
ultrasonification, biolistic method, etc. But The next step involves the production
in plant biotechnology the transformation is
through Ti plasmids of A. tumifaciens. of desired products like alcohol, enzymes,
antibiotics, etc. Finally the desired product is
d. Selection of the transformed host cell : separated and purified through downstream
The transformation process generates a processing using suitable bioreactor.

mixed population of transformed (recombinant) Do you know ?
and non-transformed (non-recombinant) host
cells. For isolation of recombinant cell from The Centre for Cellular and Molecular
non-recombinant cell, marker gene of plasmid Biology (CCMB) located in Hyderabad, is
vector is employed. For example, PBR322 a premier research organization in frontier
plasmid vector contains different marker gene areas of modern biology including DNA
(Ampicillin resistant gene and Tetracycline fingerprinting and Molecular approaches in
resistant gene). When pst1 RE is used, it knocks animal breeding. The objectives of the Centre
out Ampicillin resistant gene from the plasmid, are to conduct high quality basic research and
so that the recombinant cell become sensitive training in frontier areas of modern biology,
to Ampicillin. and promote centralized national facilities
for new and modern techniques in the inter-
e. Multiplication of transformed host cell: disciplinary areas of biology.
Once transformed, host cells are separated
12.4 Applications of Biotechnology:
by the screening process. In this step the Biotechnology is an umbrella term covering
transformed host cells are introduced into fresh
culture media. a broad spectrum of scientific applications used
in many sectors, such as health and agriculture.
At this stage the host cells divide and Industry, environment and genomics.
redivide along with the replication of the
recombinant DNA carried by them.

Animal biotechnology Plant biotechnology Industrial biotechnology
(Tissue culture, generative (plant cell and tissue culture, (Enzyme biotechnology,
meicine, immunotechnology, GM GM crops, marker-assisted protein engineering, metabolic
animals, pharmacogenomics, engineering, metabolomics)
selection)
gene therapy) Genomics
Biotechnology Whole genome sequencing,
Environmental biotechnology
(Pollution control, biofuels, Microbial biotechnology gene function, reverse
bioremediation, biodiversity) (Microbial genomics, genetics, bioinformatics)

biofertilizers, biopesticides,
IPM)

Fig. 12.6 : Applications of Biotechnology
279

Tabel 12.7 : Human proteins produced by synthesized DNA sequence of insulin for two
rDNA technology to treat human diseases chains A and B and separately inserted into two
PBR322 plasmid vector. Insulin production by
Disorder/ Diseases/ Recombinant recombinant DNA technology is designed by
Health condition protein(s) Gilbert and Villokomaroff in 1978.
1. Anaemia
2. Asthma Erythropoeitin The genes are inserted by the side of
3. Atherosclerosis Interleukin-1 receptor
Platelet derived β-galactosidase gene of the plasmid. The
4. Parturition growth factor
5. Blood clots Relaxin recombinant plasmids were then separately
Tissue plasminogen
6. Cancer Activator (TPA) transformed into E. coli host. The host
Urokinase
7. Diabetes Interferons, tumour produced penicillinase + pre-pro insulin.
8. Emphysemo necrosis factor
9. Haemophilia A interleukins, Insulin is later separated by trypsin treatment.
10. Haemophilia B macrophage
11. Hepatitis B activating factor Vaccine production:
Insulin A vaccine is a biological preparation that
a1- Antitrypsin
Factor VIII provides active acquired immunity against a
Factor IX certain disease. Usually a vaccine consists of
Hepatitis B vaccine a biological agent that represents the disease-
causing microorganism. It is often made from a
a. Healthcare Biotechnology : weakened or killed form of the microorganism,
It refers to a medicinal or diagnostic its toxins or one of its surface protein antigens.

product or a vaccine. This technology has Biotechnology has offered modern
a tremendous impact on meeting the needs diagnostictestkits-rickettsial,bacterialandviral
of patients. Biotechnology offers patients vaccines along with radiolabelled biological
a variety of new solutions such as: unique, therapeutics for imaging and analysis.
targeted and personalized therapeutic and
diagnostic solutions for organ transplant, stem Vaccines have eliminated small pox,
cell technology, genetic counselling, forensic polio and other deadly diseases for the last
medicine, gene probes, genetic fingerprinting several decades. Biotechnology has made
and karyotyping are outcomes of biotechnology. advancements in vaccination by making
recombinant vaccines that have the potential
to eradicate non-communicable diseases like
cancer. Naked DNA vaccines, viral vector
vaccines and plant-derived vaccines are found
to be most effective against a number of
bacterial and viral disorders.

Human insulin : Internet my friend
Insulin is a peptide hormone produced by
Collect the information pertaining to
β-cells of islets of Langerhans of pancreas. It recombinant vaccines and their types -
was discovered by sir Edward Sharpey Schafer protein vaccines and DNA vaccines.
(1916) while studying Islets of Langerhans.
Oral vaccines: a novel approach :
Insulin is essential for the control of blood The latest hot spot in the field of vaccine
sugar levels. Diabetes mellitus is a disease
in which some people cannot make insulin research is the development of vaccine which
themselves. Hakura et al (1977), chemically can be taken orally. Immunogenic protein of

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certain pathogens is found to be active when c. Gene therapy:
administered orally. The gene corresponding to A gene is a stretch of DNA required to
such proteins is isolated and a gene construct is
produced. This is introduced and expressed in make a functional product such as part or all of
a plant genome, which results in production of a protein. During gene therapy, DNA that codes
such immunogenic proteins in the parts of the for specific genes is delivered to individual
plant where it is expressed. These when fed into cells in the body.
animals or mainly humans, the person becomes
vaccinated against certain pathogen. Such Gene therapy is the treatment of disease
vaccines are also known as edible vaccines. by replacing, altering or supplementing a gene
that is absent or abnormal and whose absence
An exciting invention is production of ‘melt or abnormality is responsible for the disease.
in the mouth’ vaccines that can be administered
by placing them under your tongue that Most, if not all, diseases have a genetic
delivers it into the blood stream. The most factor. The genetic factor can be wholly or
important example is the production of flu partially responsible for the disease. For
vaccine by Bacillus which melts in the mouth. example, in disorders such as cystic fibrosis,
The tremendous benefit of such vaccines, is the haemophilia, and muscular dystrophy, changes
comfort of administeration, low cost and ease in a gene directly result in the condition.
of storage.
In other conditions, such as high
b. Agriculture : cholesterol and high blood pressure, genetic
Application of Biotechnology in Agriculture and environmental factors interact to cause
disease. There are more than 5000 different
involves scientific techniques such as Genetically human genetic diseases known to be caused
Modified Organisms, Bt Cotton, Pest Resistant by single gene defects e.g. sickle cell anaemia,
Plants. It helps in modifying plants, animals, thalassemia, Tay-sach’s disease, cystic
and microorganisms and improve their fibrosis, Huntington’s chorea, haemophilia,
agricultural productivity. alkaptonuria, albinism, etc.

Tissue Culture is used in Micropropagation Gene therapy is being used in many ways.
i.e. large-scale propagation of plants in very For example, to:
short durations. Tissue culture technique is also • Replace missing or defective genes;
the best method for storing germplasm and • Deliver genes that speed the destruction of
maintaining a specific genetic type (Clone).
This technique is used in those plants, which cancer cells;
produce recalcitrant seeds or produce highly • Supply genes that cause cancer cells to
variable seeds.
revert back to normal cells;
Recalcitrant means the reduction in • Deliver bacterial or viral genes as a form
the seed moisture contents below certain
levels and freezing drastically reduces the of vaccination;
servival and thus present difficulty in storage. • Deliver DNA to antigen expression and
Here, subcellular damage of seeds occur
accompanied by consequent loss of viability, generation of immune response;
when dried. • Supply of gene for impairing viral

replication;
• Provide genes that promote or impede the

growth of new tissue; and
• Deliver genes that stimulate the healing of

damaged tissue.

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Do you know ? disease, familial hypercholesterolemia,
haemophilia, phenylketonuria, cystic fibrosis,
Delivery of genes into cells : sickle cell anaemia, Duchenne muscular
Genes can be delivered by three ways : dystrophy, emphysema, thalassemia etc.
i. Ex vivo delivery where cells are removed
d. Genetically Modified Organisms (GMOs):
from the patients and then gene is These are living organisms whose genetic
introduced using viral or non-viral vectors
e.g. Parkinsons disease, a neurological material has been artificially manipulated in a
disorder. laboratory through genetic engineering. This
ii. In vivo delivery where therapeutic genes creates combinations of plant, animal, bacteria,
are directly delivered in the cells at the and virus genes that do not occur in nature or
target sites of the diseased tissue in the through traditional crossbreeding methods.
patient- like intravenous infusion genes
to treat cancer are injected directly into Most GMOs have been engineered to
tumor. withstand the direct application of herbicide
iii. Use of virosomes (Liposome + inactivated and/or to produce an insecticide. However,
HIV), bionic chips are the other methods new technologies are now being used to
of gene delivery. artificially develop other traits in plants, such
as a resistance to browning in apples, and to
Forms of gene therapy : create new organisms using synthetic biology.
a. Germ line gene therapy : In this method Despite biotech industry promises, there is
healthy genes can be introduced into germ no evidence that any of the GMOs currently
cells like sperms, eggs, early embryos. It on the market, offer increased yield, drought
allows transmission of the modified genetic tolerance, enhanced nutrition, or any other
information to the next generation. Though it consumer benefit.
is highly effective in counteracting the genetic
disorders, it is not encouraged for application I. Transgenic Plants :
in human beings due to a variety of technical The human race is very dependent on
and ethical reasons.
agriculture and as world populations continue to
b. Somatic cell gene therapy : In this type the expand, there must be continuous reassessment
gene is introduced only in somatic cells like of agricultural practices to optimize their
bone marrow cells, hepatic cells, fibroblasts efficiency. Since early times human beings have
endothelium and pulmonary epithelial cells, sought to improve the quality and productivity
central nervous system, endocrine cells and of agriculturally important plants. This was
smooth muscle cells of blood vessel walls. done by selection and traditional breeding
Modification of somatic cells only affects procedures that were painstakingly slow and
the person being treated and the modified difficult. Traditional breeding programmes
chromosomes cannot be passed on the future involve sexual crosses, which resulted in the
generations. Somatic cell gene therapy is the high quality of present day food plants such
only feasible option and the clinical trials have as wheat, rice, corn, potato, etc. More recently,
already employed for the treatment of acquired biotechnological approaches have been applied
disorders such as cancer and rheumatoid arthritis to these plants to create genetic variations that
and blood disorders including SCID, Gaucher’s are beneficial for mankind.

First transgenic plant produced was
tobacco. More then 60 transgenic dicot plants
and several monocot plant like maize, oat,

282

rice, wheat are known. Tomato, soybean, The effect of these fragments is seen within
potato, sugar beet, grapes, brinjal, cotton are minutes of ingestion, beginning with midgut
other transgenic plants. Transgenic plants are paralysis and ending with disruption of midgut
being looked up as bioreactors for molecular cells of insect. Bt toxin activity has been against
farming i.e. for production of novel drugs like many species of insects within the orders of
interferons, edible vaccines, antibodies, amino Lepidoptera, Diptera, and Coleoptera.
acids, immunotherapeutic drugs, etc.
Golden rice - a transgenic food crop used
Advantages of GM food-plants : to reduce vitamin A deficiency disease.
The ways in which one thinks that
Similarly, the gene of α-amylase inhibitor
genetically modified plants can help, are listed (αAl-Pv) has been isolated from adzuki bean
as follows: (Phaseolus vulgaris) and transferred to tobacco
a. Insect pest resistance: and this gene works against pests like Zabrotes
subfasciatus and Callosobruchus chinensis.
It can help farmers to reduce their use of
chemical pesticides, which in turn can reduce b. Improved nutritional qualities
the cost of producing food. However, an (biofortification):
alternative has been available for more than
30 years which is a biological insecticide from Transgenic plants have also been produced
the bacterium, Bacillus thuringiensis (Bt). to provide functional food and neutraceuticals.
However, the use of B. thuringiensis sprays is For millions of people in developing countries,
limited because of low stability of the protein rice is the main item in their diet. Because
in the field. rice does not contain many essential nutrients,
malnutrition is very common in these countries.
Bt cotton is one of the best transgenic
plants known for its insect resistance property. Especially terrible is the blindness that
results from a lack of vitamin A. This vitamin
Insect resistant plants contain either a gene is abundant in milk and in vegetables such as
from B. thuringiensis or the cowpea trypsin carrots, which most of the poor people of the
inhibitor gene. The gene called cry gene present world cannot afford. To solve this problem,
in B. thuringiensis produces a protein that forms Swiss researchers created transgenic rice
crystalline inclusions in bacterial spores. When (golden rice) and transgenic mustard (golden
ingested by a susceptible insect, a combination mustard) varieties that are high in vitamin A.
of high pH and the enzyme proteinase of the The golden colour is due to vitamin A. They
insect’s midgut, processes them hydrolytically hoped that this rice, if grown and eaten in
to release the core toxic fragments. developing countries, would reduce the diseases
associated with vitamin A deficiency (VAD).

Table 12.8 : Some transgenic plants produced for functional food and neutraceuticals

Substance Potential benefit Crop Transgene

Provitamin A Anti-oxidant Rice Phytoene synthase, lycopene cyclase
Vitamin E Anti-oxidant Canola γ- tocopherol methyl trasnferase
Flavonoids Anti-oxidants Tomato Chalone isomerase
Fructants Low calories Sugarbeet 1-sucroese: sucrase fructosyl transferase
Iron Iron fortification Rice Ferritin, metallothioein, phytase

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Improvement in oil content and oil quality of Most of these physiological changes are
oil crops like soybean, oil palm, rapeseed and due to endogenous enzyme activity. Genetic
sunflower, have been achieved by transfer of engineering has made it possible to slow down
‘Arabidopsis genes’. these activities. In the tomato the enzyme
polygalacturonase breaks down the cell wall
Iron deficiency is also a serious nutritional constituent- pectin, leading to softening of
problem, affecting an estimated 30% of the fruit during ripening. Thus, the fruits are easily
world population. For production of transgenic bruised and damaged on shipment. By inhibiting
crops that will produce food rich in iron, an iron the polygalacturonase by antisense genes, the
storage protein (ferritin) is targeted. Ferrritin is tomato (genetically modified tomatoes are
found in many animals, plants and bacteria. called Flavr savr tomatoes) can remain on the
The genes for ferritin protein isolated from vine until mature and be transported in a firm
soybean and Phaseolus have been transferred solid state.
to rice.

Do you know ? d. Plants as factories :
To produce novel biochemicals and
• Genetically engineered herbicide
tolerant plants are developed as in maize, vaccines (Biopharmaceuticals), plants are
wheat and many other monocot plants. potential factories or bioreactors for high
value biochemicals like starch, sugar, lipids,
• Genetically engineered disease resistant proteins, and products like fine chemicals,
plants (against bacterial and viral perfumes and adhesive compounds as well as
pathogenes) are also developed in crop industrial lubricants, biodegradable plastic and
plants like tomato, potato and tobacco. even ‘renewable’ energy crops to replace fossil
fuels.
• Plants deficient in amino acids like
methionine, lysine and tryptophan are Biopharmaceuticals are proteins,
genetically engineered by introducing hormones, antibodies, vaccines or enzymes
genes from other sources so as to make isolated from transgenic plants. Some of the
the seeds protein rich. e.g. Leguminous proteins that are being produced by transgenic
plants (pulses), maize, etc. crop plants:

• Similarly, genetically engineered plants • Human growth hormone with the gene
tolerant to abiotic stresses such as high inserted into the chloroplast DNA of
temperature, water, cold, etc. are also tobacco plants.
developed.
• Humanized antibodies against such
c. Modification in Post-harvest infectious agents as HIV, Respiratory
characteristics: syncytial virus (RSV), Herpes simplex
virus (HSV), the cause of "cold sores"
Diseases and pests, bruising on soft fruits
and vegetables, heat and cold storage, over- • Protein antigens to be used in vaccines
ripeness, loss of flavours and odours, etc. for e.g. Patient-specific antilymphoma (a
lead to great deal of losses during storage and cancer) vaccines. B-cell lymphomas are
transport of crops. clones of malignant B cells expressing on
their surface a unique antibody molecule.
Currently many novel products have been

commercially exploited for their products such
as:

284

a. A ‘superglue’ produced by tobacco plants there has been a deliberate modification of the
with genes encoding for powerful adhesive genome - the material responsible for inherited
proteins, enables marine mussels to stick characteristics - in contrast to spontaneous
to rocks. It will be especially valuable mutation. Foreign DNA is introduced into the
as a biochemical glue for body repairs animal, using recombinant DNA technology,
during surgery. and then must be transmitted through the germ
line so that every cell, including germ cells, of
b. Transgenic plants, containing oil- the animal contain the same modified genetic
encoding gene from marine algae, material.
produce oil that has nutritional value
similar to cod- liver oil. A representative, but non-inclusive, list
of purposes for which transgenic animals
c. Plant that will produce the antimalarial have been used, indicates the wide-ranging
drug, Artemisinin. application of this biotechnology:

d. Genetically engineered opium poppy to • in medical research, transgenic animals
produce more powerful painkillers. are used to identify the functions of specific
factors in complex homeostatic systems
e. Transgenic plants producing edible through over- or under-expression of a
vaccines: modified gene (the inserted transgene);

Genetically altered plants can provide • in toxicology: as responsive test animals
protection to infectious diseases. Plant products (detection of toxicants);
acting as vaccines would be inexpensive to
produce and thus, can easily be made available • in mammalian developmental genetics;
in developing countries. Potatoes, tomatoes,
bananas, soybeans, alfalfa and cereals are • in molecular biology, the analysis of the
the most common foods proposed for edible regulation of gene expression makes use
vaccine delivery. of the evaluation of a specific genetic
change at the level of the whole animal;
II. Transgenic animals:
Many transgenic animals such as mice, rats, • in the pharmaceutical industry, targeted
production of pharmaceutical proteins,
rabits, pig, sheep, cows, fowls, fish have been drug production and product efficacy
produced through rDNA technology. The term testing;
transgenic animal refers to an animal in which

Transgenic fowl Transgenic fish for
for meat and eggs protein rich meat

Transgenic mouse as Transgenic cow as
animal model for research bioreactor

Fig. 12.9 : Transgenic animals
285

• in biotechnology: as producers of specific The main objectives for improved animal
proteins; breeding programmes coupled with this new
technology of gene transfer are given below.
• genetically engineered hormones to • Efficiency of meat production
increase milk yield, meat production; • Improved quality of meat
genetic engineering of livestock and • Milk quality and quantity
in aquaculture affecting modification • Egg production
of animal physiology and/or anatomy; • Wool quality and quantity
cloning procedures to reproduce specific • Disease resistance in animals
blood lines; and • Production of low-cost pharmaceuticals

• developing animals specially created for and biologicals
use in xenografting.

a. Transgenic mice and cancer research : c. Transgenic cattle for food production :

Through laboratory investigations with Of the few research reports describing the

transgenic mice that have been modified using use of transgenic technologies in cattle only

a particular oncogene (cancer causing gene) one is directed towards a food production

and thus developed a certain type of cancer, application. Researchers introduced additional

questions concerning the relationship between copies of bovine beta or kappa casein into

oncogenes and cancer development could be dairy cattle and evaluated the effect on milk

answered. Theoretically, such animals can also production and composition. Transgenic

be used for research into cancer treatment and offspring had an 8 to 20% increase in beta

prevention of malignancy. casein and a two-fold increase in kappa casein.

In the laboratory of Philip Leder in d. Transgenic cattle for human therapeutic
Harvard (USA) the transgenic mouse model production :
for the investigation of the breast cancer was
developed. The oncogenes myc and ras were A second application for genetically
analysed to find out if they lead to breast cancer modified cattle is the production of human
in mice transformed with these genes. therapeutic proteins. Human proteins that
have been expressed in milk include human
b. Transgenic farm animals : lactoferrin, human alpha lactalbumin, human
With the advent of technology, the intention serum albumin and human bile salt stimulated
lipase. The mammary gland in dairy cows is
of researchers is diverted to produce transgenic an excellent protein production factory. On the
farm animals from which the mankind can other hand, one transgenic cow would be more
derive greater benefits. Many of the farm than sufficient for production of annual world
animals are improved for their meat production supply of factor IX (plasma thromboplastin
ability while some of them are improved for component) that is used in the treatment of
milk yields and quality, and disease-free status. haemophilia.
At the beginning of the century, a dairy cow
provided 2,000 to 3,000 liters of milk a year. In 1990 Tracy, the transgenic cow was
born in Scotland, and could produce a human
Today, Holstein cow provides 6,000 liters protein in her milk for human therapeutics.
on average and up to 8,000 – 10,000 for the
best ones. A century ago, a hen laid about 70 Antibodies are currently used for many
eggs a year whereas today the best races lay different human clinical applications; including
up to 250 eggs per year. This could be possible treatment of infectious disease, cancer,
because of the advent of biotechnology.

286

transplanted organ rejection, autoimmune h. Transgenic chicken :
diseases and for use as antitoxins. To make Also carry and express foreign genes. They
a human antibody product, the genetically
modified cows are immunized with a vaccine could be used to improve the genetic make-up
containing the disease agent. of existing strains with respect to built-in (in
vivo) resistance to viral and coccidial diseases,
e. Transgenic Sheep : better feed efficiency, lower fat and cholesterol
Gene transfer technology is applied to levels and high protein containing eggs, and
better meat quality.
sheep to produce transgenic sheep which
are able to achieve better growth and meat 12.5 Bioethics, bio-piracy and bio-patent :
production as well as to serve as bioreactors. Bioethics:
Human growth hormone gene is introduced
in sheep for promoting the growth and meat Ethics usually deals with the matters
production. related to socially acceptable moral duty,
conduct and judgement. In otherwords, it helps
Bacterial genes, cys E and cys M, are to regulate the behaviour of cummunity by
concerned with biosynthesis of cysteine amino some set of standards. However the concepts
acids involved in formation of keratin protein differ according to culture and traditions.
found in wool. Both these genes are identified, Moreover concepts change with the time due
cloned and introduced in sheep to increase wool to shifting of perception of values which are
production and to improve the quality of wool. affected by progress in science and technology.
Bioethics helps to study moral vision, decision
f. Transgenic pigs : and policies of human behaviour in relation to
The objective of gene transfer in pigs is to biological phenomena or events. Ethics deals
with ‘Life’e.g. in vitro fertilization, sperm bank,
increase growth and meat production and to act gene theropy, cloning, gene manipulations,
as bioreactors. euthanasia, death, maintaining those who are
in comatose state, prenatal genetic selection,
Pigs are regarded as the most suitable etc.
animals to be bred for heart transplant because
a pig’s heart is about the same size as a human The era of biotechnology has brought wide
heart, and pig heart valves have been used in spectrum on new topics like cloning, transgenic,
human heart surgery for over a decade. The pig gene therapy, eugenics, rDNA technology, etc.
clone is the first step towards providing animal The use of all these has drawn a wide range
organs and tissues for human transplants of reactions in the society. The reactions are
(xenotransplantation). based on individual’s own perception and
moral. Ethical aspects pertaining to the use of
g. Transgenic fish : biotechnology seems to be more controversial
The commercially important fish like and frightening. These concerns are broadly
summarized below :
Atlantic salmon, catfish, goldfish, Tilapia,
zebra-fish, common carp, rainbow trout, etc. Use of animals causes great sufferings to
are transfected with growth hormone, chicken them; voilation of integration of species caused
crystalline protein and E.coli hygromycin due to transgenosis; transfer of human genes
resistance gene. Transgenic fish showed into animals and vice versa; indiscriminate use
increased cold tolerance and improved growth of biotechnology pose risk to the environment,
and it is the quantity and quality of fish proteins health and biodiversity.
as well as its preservation, are the factors
affecting the economic value of fish.

287

The introduction of Genetically Modified 12.7 Effects of Biotechnology on Human
Organisms (GMOs) has led to a wider debate
on bioethical concerns affecting social, Health :
economic and environmental spheres. These
include the effects on non-target organisms, a. Allergies :
insect resistance crops, gene flow and the loss GMO crops could potentially have negative
of diversity as well as the issue on interfering
with nature in which the modification process effects on human health as well. Consumers
itself is disrupting the natural process of have developed unexpected allergic reactions.
biological entities. Ethics in biotechnology also e.g. Researchers used a gene from the Brazil
includes the general subject of what should and nut to increase the production of Methionine
should not be done in using recombinant DNA in soya beans. The insertion of this gene
techniques inadvertently caused allergic reactions to the
soya bean in those with known nut allergies
12.6 Effects of Biotechnology on the (“Biotech Soybeans”).
Environment : b. Long-Term Effects :
a. Herbicide Use and Resistance :
Because GMO technology has been
Effects on the environment are a particular available for such a short amount of time, there
concern with regard to GMO crops and food is relatively little research which has been
production. One area of development involves conducted on the long-term effects on health
adding the ability to produce pesticides and which we cannot anticipate at this point.
resistance to specific herbicides. These traits c. New Proteins :
are helpful in food production, allowing
farmers to use fewer chemicals, and to grow Proteins that have never been ingested
crops in less than ideal conditions. However, before by humans are now part of the foods
herbicide use could be increased, which will that people consume every day. Their potential
have a larger negative effect on the surrounding effects on the human body are as of yet
environment. Also unintended hybrid strains of unknown.
weeds and other plants can develop resistance d. Food Additives :
to these herbicides through cross-pollination,
thus negating the potential benefit of the GMOs also present us with possibilities
herbicide. One such herbicide that has already of introducing additional nutrients into foods,
been added is RoundUp. Crops of RoundUp- as well as antibiotics and vaccines. This
ready soybeans have already been implemented availability of technology can provide nutrition
into agricultural practices, possibly conferring and disease resistance to those countries
RoundUp resistance to neighboring plants. that don’t have the means to provide these,
otherwise.
b. Effects on Untargeted Species :
Bt corn, which produces its own pesticide, However, there is possibility of the creation
of antibiotic and vaccine-resistant strains of
is also in use today. It has adverse effects on diseases.
Monarch butterfly populations, which are not
the original target of the pesticide. It can also This shows that the vast advances in life
have unintentional effects on neutral or even sciences and our multicultural and pluralistic
beneficial species. modern societies create numerous bioethical
problems requiring some stringent regulation.
In terms of GMOs, the Indian Government
has set up the Genetic Engineering Approval
Committee (GEAC). This organization makes
decisions regarding the validity of research
involving GMOs and addresses the safety of

GMOs introduced for public use.

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12.8 Biopatent and Biopiracy : b. Biopiracy :
Pirates in general terms are those who
a. Biopatent :
Patent is a special right granted to the steal and kill others to enrich themselves.
Biopirates are those who do not kill but steal
inventor by the goverment. Patent is a personal the patent (misuse the patent). Biopiracy is
property of inventor. It can be sold like any defined as ‘theft of various natural products
other property. A patent consists of three and then selling them by getting patent without
parts - grant (aggrement with the inventor), giving any benefits or compensation back to
specification (subject matter of invention) and the host country’. In short, it is unauthorized
claims (scope of invention to be protected). misappropriation of any biological resource
and indigenous knowledge.
Biopatent is a biological patent. Biopatents
are awarded for strains of microorganisms, Most developed, industrialized and
cell lines, genetically modified strains, DNA financially rich nations are poor in biodiversity
sequences, biotechnological processes, product or traditional knowledge whereas developing
processes, product and product applications. and underdeveloped nations have ample of
biodiversity and they traditionally better know
Biopatents are awarded to recognize real the use of their bio-resources. Traditional
innovative contributions made by the inventor Knowledge naturally includes a deep
to the cause of human welfare. The awards understanding of ecological processes and the
are given to inculcate encouragement and ability to sustainably extract useful products
values in developing scientific culture and in from the local habitat. Most Traditional
emphasizing the role of biology in shaping Knowledge is handed down through
human society. generations. This helps them to develop modern,
commercial applications that save the makers
Indian patent allows ‘process patent’ and time, money and effort.
not the ‘product patent’. Biopatent allows the
patent holder to exclude others from making, Components of Traditional Knowledge that
using, selling or importing protected invention are especially relevant to our global survival
for a limited period of time. Duration of include knowledge of:
biopatents is five years from the date of the • Food, crop varieties and agricultural/
grant or seven years from the date of filing the
patent application, which ever is less. farming practice
• Sustainable management of natural
First biopatent was patented pertaining
to genetically engineered bacterium resources and conservation of biological
‘Pseudomonas’ used for clearing oils spills. diversity
Patent under the title ‘control of plant gene • Biologically important medicines
expression’ was issued jointly to Delta and
Pineland company and U. S. department of The conservation of species, habitat, and
agriculture. Patent is based on a gene that biodiversity are essential to the continued
produces a protein toxic to plant thus, do not survival of indigenous and rural people.
allow seeds to germinate. However, this patent By conserving the customs and habitat of
was not granted by Indian goverment. Such indigenous persons, we concurrently reduce
a patent is considered morally unacceptable emissions from deforestation and ecosystem
and fundametally unequitable. This is because degradation. Furthermore, the opportunity for
financially powerful corporations would aquire cultural survival is a basic human right. The
monopoly over biotechnological process. This traditional knowledge is facing a problem of
in turn would pose a threat to global food bio-piracy.

security.

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The act of Piracy is unauthorized name Texmati. The patent application was
publication or reproduction of another person’s based on 20 very broad claims on having
work or material. When someone indulges in “invented” the said rice. Due to peoples
piracy, the accused is using someone’s work movement against Rice Tec in March 2001, the
illegally or without taking any permission. UPSTO has rejected all the claims.
The innovations and discovery of the
pharmaceutical and agricultural researches • Haldi (Turmeric) Biopiracy :
are not new as to qualify as invention as they Two American researchers of Indian
are based on centuries of knowledge of the
traditional societies. origin of the University of Mississippi Medical
Center, put a claim to the US Patent and
Examples of Biopiracy : Trademark Office, maintaining that they
• Patenting of Neem (Azadirachta indica) : had discovered haldi's healing properties.
Surprisingly, they were granted a patent in
The people of India in a variety of ways March 1995 for something you had known for
have used neem, since time immemorial. years and our ayurvedas for centuries.
Indians have shared the knowledge of the
properties of the neem with the entire world. It meant they had exclusive rights over any
Pirating this knowledge, the USDA and an such haldi drug and were in a position to make
American MNC W.R. Grace in the early 90s millions of dollars. The Council of Scientific
sought a patent from the European Patent Office and Industrial Research (CSIR) applied to
(EPO) on the “method for controlling on plants the US Patent Office for a reexamination and
by the aid of hydrophobic extracted neem oil.” they realized the mistake and cancelled the
The patenting of the fungicidal properties of patent. This was after Indian scientists shouted
Neem, was an example of biopiracy. from rooftops about how we are losing our
traditional knowledge to marauding foreign
• Patenting of Basmati : companies who have started poaching on our
Basmati is a long-grained, aromatic variety ancient healing techniques.

of rice indigenous to the Indian subcontinent. It is the need of hour to launch genetic
literacy movement in Indian school and colleges
In 1997 the US Patent and Trademark for better understanding of opportunities
Office (USPTO) granted a patent to a Texas and risks related to biotechnology and also
based American company Rice Tec Inc for to promote the safe and meaningful use of
“Basmati rice line and grains” having trade technologies of modern life sciences.

Activity :

Collect information on the use of Biotechnology in pollution control.

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Exercise

Q. 1 Choose the correct option 6. Recognition sequence of restriction
1. The bacterium which causes a plant
disease called crown gall is ................ enzymes are generally ...............
b. Helicobacter pylori
c. Agrobacterium tumifaciens nucleotide long.
d. Thermophilus aquaticus
e. Bacillus thuringienesis a. 2 to 4 b. 4 to 8

2. The enzyme nuclease hydrolyses c. 8 to 10 d. 14 to 18
............... of polynucleotide chain of
DNA. Q. 2 Very short answer type questions.
a. hydrogen bonds 1. Name the vector which is used in
b. phosphodiester bonds protuction of human insulin through
c. glycosidic bonds recombinent DNA technology.
d. peptide bonds
2. Which cells from Langerhans of
3. In vitro amplification of DNA or RNA pancreas do produce a peptide hormone
segment is known as ............... insulin?
a. chromatography
b. southern blotting 3. Give the role of Ca++ ions in the transfer
c. polymerase chain reaction of recombinent vector into bacterial host
d. gel electrophoresis cell.

4. Which of the following is the correct 4. Expand the following acronyms which
recognition sequence of restriction are used in the field of protechnology.
enzyme hind III.
a. 5’ ---A-A-G-C-T-T---3’ i. YAC ii. RE iii. dNTP
3’ ---T-T-C-G-A-A--- 5’
b. 5’ ---G-A-A-T-T-C---3’ iv. PCR v. GMO vi. MAC
3’ ---C-T-T-A-A-G--- 5’
c. 5’ ---C-G-A-T-T-C---3’ 5. Fill in the blanks and complete the chart.
3’ ---G-C-T-A-A-G--- 5’
d. 5’ ---G-G-C-C---3’ GMO Purpose
3’ ---C-C-G-G--- 5’ i. Bt cotton ....................
ii. ................... Delay the softening of
5. Recombinant protein .................. is used tomato during ripening.
to dissolve blood clots present in the ii. Golden rice ....................
body. iv. Holstein cow ....................
a. insulin
b. tissue plasminogen activator Q. 3 Short answer type questions.
c. relaxin 1. Explain the properties of a good or ideal
d. erythropoietin cloning vector for rDNA technology.
2. A PCR machine can rise temperature
upto 100 0C but after that it is not able
to lower the temperature below70 0C
automatically. Which step of PCR will
be hampered first in this faulty machine?
Explain why?

3. In the process of rDNA technology, if two
separate restriction enzymes are used to

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