Introduction to Biotechnology
· Biotechnology is concerned with the application of living cells or their components for the benefit of humans.
· Biotechnology is the utilization of biological knowledge for the production of material useful to society.
· Biotechnology is an important tool used for the production of food crops, livestock management, human health care, chemical industries and environmental management.
· Term ‘biotechnology’ was coined by Karl Ereky.
· Old biotechnology was based on the natural capabilities of microorganisms.
· Modern biotechnology is concerned with microbiology, biochemistry, tissue culture chemical engineering and genetic engineering molecular biology and immunology.
· The US National science foundation had defined “The controlled use of biological agents such as micro-organism or cellular components for beneficial use.”
· Alcohol fermentation is a common traditional practice of biotechnology.
Various Branches of Biotechnology:
(A) Alcohol Fermentation
(B) Plant Breeding or Improvement of Crops
(C) Animal Breeding
(D) Plant Tissue Culture
(E) Protoplast culture
(F) Genetic Engineering
(G) Hybridoma Technology (Production of vaccines)
· Yeast species used in fermentation are Saccharomyces cerevisiae (Brewer’s yeast), S. ellipsoidens (Wine yeast), S. sake, S. piriformis, Baker’s yeast (selected strains of Saccharomyces)
· Nutrient mediums are
· Barley malt for beer
· Fermented Rye Malt for gin
· Potato for vodka
· Mash: Crushed food mixed with hot water for obtaining malt is called mash i.e. Molasses with hot water.
· Wort: The sweetened nutrient medium prior to alcoholic fermentation is called Wort.
Method of Fermentation
1. The liquid nutrient medium or Wort is added to the Bioreactor or Fermentation tank.
2. When a liquid nutrient medium is cooled down to the appropriate temperature, it is inoculated with an appropriate strain of yeast.
Fermentation occurs in 3 ways:
(i) Batch Process:
· Yeast and nutrient are allowed to remain in the tank till maximum alcohol content is achieved. It is called Wash.
· Now it is removed completely and the tank is sterilized for the next batch.
(ii) Continuous Process:
· There is regular removal of a portion of fermented liquor/wash and addition of more nutrients.
(iii) Immobilised Yeast:
· Yeast is used in the immobilized state in calcium alginate beads. This technique is 20 times more efficient.
Step of Alcohol Fermentation
(i) Upstream Process:
· Operations before starting the fermentation like the selection of raw materials, purities of materials, types of yeasts, sterilization of bioreactor, regulation of temperature, pH, preparation of culture media.
(ii) Downstream Process:
· Operations after the fermentation like filtration of broth, sedimentation, decantation, centrifugation, distillation, extraction, rectification, purification etc.
· Varieties which are far better than original varieties in all aspects.
Methods of Plant Breeding
(a) Introduction and Acclimatization
· Most rapid and easiest method of plant breeding.
· Process of introducing of plant from their original locality to new location.
· The plant is supposed to adjust to the new environment by the process of acclimatization.
· Introduction process is followed by Quarantine, in case, the newly introduced plants may be invaders and propagate as invasive alien species.
· Some invasive alien species in Nepal are Argemone mexicana, Eupatorium etc.
(e) Mutation Breeding:
· Drastic inheritable changes in offspring.
· Mutation can be induced by using
(i) Chemical Mutagens: Hydrazines, Methyl methane sulphonate (MMS), Nitrous acid, Ethyl methane sulphonate (EMS)
(ii) Physical Mutagens: X-rays, Gamma-rays, Beta-rays, UV rays etc.
· Commonly used mutation in plant breeding is Point or gene mutation.
1. In-breeding:
· Process of mating closely related individuals eg; Merino sheep (for producing fine wool), modern horse.
· It increases homozygosity.
· Continued inbreeding reduces fertility and productivity.
2. Out-breeding or Hybridization:
· Process of mating two unrelated individuals.
· Experimentally explained by Steward et all.
· In tissue culture, a mass of cells or single cell is taken for experiment; known as Explant.
· The explant is provided with culture media containing sufficient nutrients.
· It gives the mass of undifferentiated cells known as a callus.
· In presence of shoot and root initiating hormones the callus starts organogenesis and ultimately produces plantlets.
· Meristem tissue culture is used to obtain virus-free plants.
· The fusion of protoplasm or somatic hybridization is protoplast culture.
· In protoplast fusion, protoplasts are fused by using a suitable agent called fusogen. The most common fusogen is polyethene glycol.
Micropropagations: The rapid multiplication or propagation of valuable crops in forestry, agriculture and horticulture through tissue culture is micropropagation.
· It is done under bacteria-free conditions.
· It involves following 3 steps.
(a) Multiplication of shootlets using cytokinin.
· This technique is also known as Recombinant DNA technology or gene cloning.
Steps of Genetic Engineering
(i) Isolation of target genes:
· Target genes are isolated from the organism by using specific enzymes (restriction endonucleases, also known as molecular scissors or genetic scalpels).
(ii) Transfer of DNA
· Transfer of specific DNA from one organism to another.
· The isolated foreign DNA with protoplast is incubated by electroporation (by applying high electricity for microsecond separate DNA from protoplast) and DNA is injected into other cells by using a fine needle.
(iii) Cloning
· In this step the foreign DNA and plasmid DNA are joined with the help of enzyme DNA ligase to give rise to recombinant DNA.
· Hybrid or recombinant DNA, which when introduced into a living cell, replicates into multiple copies.
Major Types of Vectors
(i) Plasmids
(ii) Cosmids
(iii) Bacteriophages
Important Tools for Genetic Engineering
· Exonucleases
· Endonucleases
· DNA ligase
Application of Genetic Engineering
(a) Synthesis of vaccines
(b) Synthesis of hormones
(c) Synthesis of interferons and monoclonal antibodies
(d) Synthesis of antibiotic
(e) Eugenics
(f) Euthenics
(g) Genetic counselling
(h) Bio-fertilization
· These are the micro-organisms that cause soil nutrient enrichment are considered to be biofertilizers.
· Biofertilizers are of 3 types
1. Bacterial Biofertilizers:
(a) SYMBIOTIC BACTERIAL BIOFERTILIZERS
· Rhizobium leguminosarum and other species form mutually beneficial associations with root nodules of legumes.
· Root nodule consists of leghaemoglobin.
· The bacteria can convert the free nitrogen of the atmosphere into nitrates.
(b) FREE LIVING NITROGEN-FIXING BACTERIA
· Examples: Acetobacter (aerobic), Clostridium (anaerobic), Beijerinckia (aerobic), Rhodopsuedomonas, Rhodospirillium, Chromatium etc.
· Soil is enriched through exudation as well as the formation of nitrates after their death and decay.
(a) Tissue Transplantation:
· Usually done with skin and part of bone e.g. in cases of a serious burn, broken bones etc.
Types:
(i) AUTOGRAFTS
· One’s own tissue is grafted to another part of the body; most successful type of transplantation.
(ii) ISOGRAFTS
· Grafting of tissue is done between identical / Homozygotic twins i.e. the donor and the recipient are genetically identical.
(iii) ALLOGRAFTS
· Transplantation occurs between individuals of the same species but with different genetic backgrounds.
(iv) XENOGRAFTS or HETEROGRAFTS
· Transplantation occurs between members of different species. E.g. Transplantation from pig to human being.
· In IVF, an unfertilized egg or ovum is taken out from the lady and kept under an aseptic condition in a test tube.
· Sperms are taken from her husband (or donor) and mixed with the ovum for fertilization.
· After completion of fertilization, the zygote is formed and allowed to develop in vitro up to 32 celled stage.
· The embryo of 32 celled stage is transplanted to the female uterus.
· The first successful test-tube baby was born on 25 July 1978 named Louse Joy Brown.
· The first test-tube baby of Nepal is OM MANE TAMANG who was born in 20th Falgun 2061 in Om Hospital and Research Centre.
· In vitro fertilization technology was first pioneered in humans by Prof. Robert Winston.
· It was devised by Patrick Steptoe and Robert Edward.
· Surrogate mother is one who lends her uterus for implantation of the fertilized egg in case the original mother is unfit for the same.
· It is useful to test prenatal genetic disorders, sex determination of baby etc.
· In amniocentesis, a hypodermal syringe is passed to peripheral fluids of the foetus.
· These are the substances produced by micro-organisms that selectively suppress the growth or kill other micro-organisms at very low concentrations.
· The term “antibiotic” was coined by Selman A. Waksman.
· First synthesized antibiotic is Penicillin; which was extracted from Penicillium notatum (fungi) by Alexander Fleming (1928).
(ii) Bactericidal
· Killing pathogenic micro-organism.
· Examples: Penicillin, Cephalosporin etc.
· In 1796, the British Physician Edward Jenner introduced a vaccine against cowpox.
2. Human insulin is commercially obtained from E.coli
3. Transgenic animals are those which have foreign DNA in all of their cells
4. Antibiotic inhibits the growth of bacteria and fungi
5. Enzymes, vitamins and hormones can be classified into a single category of biological chemicals because all these help in regulating metabolism
6. Genetic engineering is possible because restriction endonucleases purified from bacteria can be used in vitro
7. Molecular scissors used in genetic engineering is a Restriction endonuclease
8. Utilisation of living organisms for producing material useful to human society is human as Biotechnology.
11. Emasculated flowers are bagged to prevent pollination
13. The material of biological origin used for maintaining and improving soil fertility is green manure
14. The nitrogen-fixing bacteria associated with maize root belongs to the genus Azospirillum
15. The phenomenon of using a predator for controlling a pest is biological control
16. The tissue or plant part removed from the plant body for culture is called explant
18. The most common endomycorrhiza is Aspergillus niger
19. The most common type of tissue transplantation is skin transplantation
20. Antibiotics are produced by bacteria
21. The material of biological origin, which is used to maintain and improve soil fertility is green manure
22. Desired improved varieties of economically useful crops are raised by hybridization
23. Branch dealing with the production of superior varieties is called plant breeding
24. Amniocentesis is used for determining hereditary disease of embryo
25. A gene carried by recombinant DNA technology is cloned when its host bacterium divides by binary fission
26. Two bacteria found to be very useful in genetic engineering experiments are Escherichia and Agrobacterium
27. Ectomycorrhiza absorbs and stores nitrogen, phosphorus, potassium and calcium in the fungal mantle
(A) Alcohol Fermentation
(B) Plant Breeding or Improvement of Crops
(C) Animal Breeding
(D) Plant Tissue Culture
(E) Protoplast culture
(F) Genetic Engineering
(G) Hybridoma Technology (Production of vaccines)
(A) ALCOHOL FERMENTATION
· It is the process of incomplete oxidation of organic compounds like carbohydrates into ethanol, carbon dioxide and metabolic energy by anaerobic organisms.· Yeast species used in fermentation are Saccharomyces cerevisiae (Brewer’s yeast), S. ellipsoidens (Wine yeast), S. sake, S. piriformis, Baker’s yeast (selected strains of Saccharomyces)
· Nutrient mediums are
· Barley malt for beer
· Fermented Rye Malt for gin
· Potato for vodka
· Mash: Crushed food mixed with hot water for obtaining malt is called mash i.e. Molasses with hot water.
· Wort: The sweetened nutrient medium prior to alcoholic fermentation is called Wort.
Method of Fermentation
1. The liquid nutrient medium or Wort is added to the Bioreactor or Fermentation tank.
2. When a liquid nutrient medium is cooled down to the appropriate temperature, it is inoculated with an appropriate strain of yeast.
Fermentation occurs in 3 ways:
(i) Batch Process:
· Yeast and nutrient are allowed to remain in the tank till maximum alcohol content is achieved. It is called Wash.
· Now it is removed completely and the tank is sterilized for the next batch.
(ii) Continuous Process:
· There is regular removal of a portion of fermented liquor/wash and addition of more nutrients.
(iii) Immobilised Yeast:
· Yeast is used in the immobilized state in calcium alginate beads. This technique is 20 times more efficient.
Step of Alcohol Fermentation
(i) Upstream Process:
· Operations before starting the fermentation like the selection of raw materials, purities of materials, types of yeasts, sterilization of bioreactor, regulation of temperature, pH, preparation of culture media.
(ii) Downstream Process:
· Operations after the fermentation like filtration of broth, sedimentation, decantation, centrifugation, distillation, extraction, rectification, purification etc.
Types of Alcoholic Beverages
(a) Fermented beverages:
(i) Beer (3 – 6% alcohol)
· Yeast used: Saccharomyces ellipsoidens
· Nutrient media: Ripe grapes; Barley malt.
(ii) Wine (10 – 20% alcohol)
· Fermentation of ripe grapes by S. ellipsoidens.
(b) Distilled beverages:
(i) Whisky (40% alcohol)
· Obtained by distillation of most of the malted/unmalted cereals.
(ii) Rum (40% alcohol)
(iii) Brandy (43 – 57% alcohol)
(iv) Gin (40 % alcohol)
(v) Vodka: By distillation of fermented mass of potato.
(a) Fermented beverages:
(i) Beer (3 – 6% alcohol)
· Yeast used: Saccharomyces ellipsoidens
· Nutrient media: Ripe grapes; Barley malt.
(ii) Wine (10 – 20% alcohol)
· Fermentation of ripe grapes by S. ellipsoidens.
(b) Distilled beverages:
(i) Whisky (40% alcohol)
· Obtained by distillation of most of the malted/unmalted cereals.
(ii) Rum (40% alcohol)
(iii) Brandy (43 – 57% alcohol)
(iv) Gin (40 % alcohol)
(v) Vodka: By distillation of fermented mass of potato.
Other Fermented Products:
1. Cheese
· Prepared by the coagulation of casein and other minor milk protein (i.e. curdling of milk).
· Curd is heated gently to separate the cheese from a liquid called Whey.
· Curdling is done with the help of Streptococcus lactis, Lactobacillus etc.
· Cottage cheese is unripened cheese.
2. Yoghurt
· Is made by fermenting whole milk with a mixture of Lactobacillus bulgaricus, Streptococcus lactis at 40 – 46°C for 4 hours.
3. Dextran
· Prepared either through
(i) Partial hydrolysis of starch or
(ii) Partial polymerization of simple sugars through micro-organism Leuconostoc mesenteroides or enzyme dextran sucrase.
· It is a plasma extender having 6 – 10% solution of dextrin.
· Given in case of haemorrhage, shock and dehydration.
4. Organic Acids
(i) Lactic Acid
· First organic acid to be fermented.
· Nutrient media: Hydrolysed corn or potato starch, molasses etc.
· Bacteria involved: Streptococcus lactis, Lactobacillus.
· Also fungus Rhizopus.
(ii) Acetic Acid
· Obtained by fermentation of molasses or other sugar solution with Acetobacter aceti.
· 10 – 13% acetic acid that is filtered & pasteurized is Vinegar.
(iii) Citric acid is obtained by fermentation of sugar by Aspergillus niger.
(iv) Gallic acid (with help of Aspergillus niger) and Gluconic acid (with Penicillium purpurogenum).
5. Vitamins
(i) Vitamin B2 (Riboflavin)
· Nutrient medium consists of crude sugar (1%), corn syrup (1%), sulphite liquor (0.5%), some peptides of animal source and antifoaming agents.
· Microbes used are Clostridium butyricum, C. acetobutylicum and yeast-like Eremothecium etc.
(ii) B12 (Cobalamin / Cyanocobalamin)
· Nutrient medium is made up of starch, corn syrup, corn sugar or molasses.
· Organisms used are Propionibacterium frendeureichii, Psuedomonas etc.
(iii) Vitamin C (Ascorbic acid)
· First vitamin obtained through microbial activity.
· Acetobacter is helpful in the dehydrogenation of D-orbital and its conversion to L-sorbose.
· L-sorbose is the precursor of vitamin C / L-ascorbic acid.
6. Enzymes
· Enzymes are biocatalysts; Kuhne named as an enzyme.
· Buchner was the first who extracted the fermenting enzyme complex of Yeast and named it Zymase.
1. Cheese
· Prepared by the coagulation of casein and other minor milk protein (i.e. curdling of milk).
· Curd is heated gently to separate the cheese from a liquid called Whey.
· Curdling is done with the help of Streptococcus lactis, Lactobacillus etc.
· Cottage cheese is unripened cheese.
2. Yoghurt
· Is made by fermenting whole milk with a mixture of Lactobacillus bulgaricus, Streptococcus lactis at 40 – 46°C for 4 hours.
3. Dextran
· Prepared either through
(i) Partial hydrolysis of starch or
(ii) Partial polymerization of simple sugars through micro-organism Leuconostoc mesenteroides or enzyme dextran sucrase.
· It is a plasma extender having 6 – 10% solution of dextrin.
· Given in case of haemorrhage, shock and dehydration.
4. Organic Acids
(i) Lactic Acid
· First organic acid to be fermented.
· Nutrient media: Hydrolysed corn or potato starch, molasses etc.
· Bacteria involved: Streptococcus lactis, Lactobacillus.
· Also fungus Rhizopus.
(ii) Acetic Acid
· Obtained by fermentation of molasses or other sugar solution with Acetobacter aceti.
· 10 – 13% acetic acid that is filtered & pasteurized is Vinegar.
(iii) Citric acid is obtained by fermentation of sugar by Aspergillus niger.
(iv) Gallic acid (with help of Aspergillus niger) and Gluconic acid (with Penicillium purpurogenum).
5. Vitamins
(i) Vitamin B2 (Riboflavin)
· Nutrient medium consists of crude sugar (1%), corn syrup (1%), sulphite liquor (0.5%), some peptides of animal source and antifoaming agents.
· Microbes used are Clostridium butyricum, C. acetobutylicum and yeast-like Eremothecium etc.
(ii) B12 (Cobalamin / Cyanocobalamin)
· Nutrient medium is made up of starch, corn syrup, corn sugar or molasses.
· Organisms used are Propionibacterium frendeureichii, Psuedomonas etc.
(iii) Vitamin C (Ascorbic acid)
· First vitamin obtained through microbial activity.
· Acetobacter is helpful in the dehydrogenation of D-orbital and its conversion to L-sorbose.
· L-sorbose is the precursor of vitamin C / L-ascorbic acid.
6. Enzymes
· Enzymes are biocatalysts; Kuhne named as an enzyme.
· Buchner was the first who extracted the fermenting enzyme complex of Yeast and named it Zymase.
| Enzyme | Source | Applications |
|---|---|---|
| Protease | Aspergillus oryzae, Bacillus subtilis |
Manufacture of liquid glue |
| Amylase | Rhizopus oryzae, Aspergillus oryzae, A. niger |
Cleaning of hides |
| Rennin | Stomach of the calf, Mucor pusillus |
Chill proofing of alcoholic drinks |
| Cellulose | A. niger, Trichoderma | Separation & designing of fibres; clearing of starch related turbidity in juices |
| Lipase | Candida lipolytica | Preparation of cheese |
7. Bakery
· Saccharomyces cerevisiae is used.
· Bread swells up or leavens.
· Leavened bread is baked, then both alcohol & CO2 evaporate & bread become soft & porous.
1. Amino acids like lysine are commercially produced by the use of Corynebacterium glutamicin.
Note:
· Pyruvic acid is the first stable product of fermentation.
· Fermentation is carried out by the enzyme Zymase.
· Fermentation is an extracellular and exothermic process.
· Saccharomyces cerevisiae is used.
· Bread swells up or leavens.
· Leavened bread is baked, then both alcohol & CO2 evaporate & bread become soft & porous.
1. Amino acids like lysine are commercially produced by the use of Corynebacterium glutamicin.
Note:
· Pyruvic acid is the first stable product of fermentation.
· Fermentation is carried out by the enzyme Zymase.
· Fermentation is an extracellular and exothermic process.
B. PLANT BREEDING
· Plant breeding is the science of improvement in the hereditary character of crops and production of new crop· Varieties which are far better than original varieties in all aspects.
Objectives of plant breeding:
· Improvement of crop plants.
· Deals with improvement in the heredity of agricultural crop plants to get superior quality and production of new crop varieties.
· Basically, it is intended to increase qualitative characteristics (taste, nutrients, cooking, baking, etc.); quantitative characters (more production); disease resistance etc.
· Agronomic characters modification i.e. modification of characters such as height, tillering, branching etc.
· Elimination of toxic substances like removal of neurotoxic B-N-Oxalyamine alanine (OAA, which causes paralysis) from Khesari pulse.
· Resistance to lodging: Even under the application of increased irrigation and greater application of fertilizers, plants can resist lodging.
· Improvement of crop plants.
· Deals with improvement in the heredity of agricultural crop plants to get superior quality and production of new crop varieties.
· Basically, it is intended to increase qualitative characteristics (taste, nutrients, cooking, baking, etc.); quantitative characters (more production); disease resistance etc.
· Agronomic characters modification i.e. modification of characters such as height, tillering, branching etc.
· Elimination of toxic substances like removal of neurotoxic B-N-Oxalyamine alanine (OAA, which causes paralysis) from Khesari pulse.
· Resistance to lodging: Even under the application of increased irrigation and greater application of fertilizers, plants can resist lodging.
Methods of Plant Breeding
(a) Introduction and Acclimatization
· Most rapid and easiest method of plant breeding.
· Process of introducing of plant from their original locality to new location.
· The plant is supposed to adjust to the new environment by the process of acclimatization.
· Introduction process is followed by Quarantine, in case, the newly introduced plants may be invaders and propagate as invasive alien species.
· Some invasive alien species in Nepal are Argemone mexicana, Eupatorium etc.
(b) Selection
· It involves the selection of the better plants out of the entire population, naturally or artificially.
(i) Natural Selection:
· Based on the natural selection of Darwin for the survival of the fittest which says “the best survives and the rest disappear”.
· It involves the selection of the better plants out of the entire population, naturally or artificially.
(i) Natural Selection:
· Based on the natural selection of Darwin for the survival of the fittest which says “the best survives and the rest disappear”.
(ii) Artificial Selection:
· Selection based either on phenotypic expression or genetic make-up.
· Selection based either on phenotypic expression or genetic make-up.
i. Pure Line Selection:
· A pure line is the progeny of a single self-fertilized homozygous plant.
· Pure line selection is the process of isolating a desirable homozygous individual from a mixed population and multiplying the same without contamination to produce a new variety.
· Plants are selected from a mixed population on the basis of their genotypes.
· Most of the improved varieties of rice, Wheat, Pulses, oilseeds etc. are developed by pure line selections.
· Pure line selection is the process of isolating a desirable homozygous individual from a mixed population and multiplying the same without contamination to produce a new variety.
· Plants are selected from a mixed population on the basis of their genotypes.
· Most of the improved varieties of rice, Wheat, Pulses, oilseeds etc. are developed by pure line selections.
ii. Mass selection:
· Commonest and oldest method for crop improvement.
· Plants are selected from the mixed population on the basis of their phenotypes.
· Generally done in cross-pollinated crops.
· Plants are selected from the mixed population on the basis of their phenotypes.
· Generally done in cross-pollinated crops.
iii. Clonal selection:
· Method of developing varieties from the clones (all the progenies of a single plant produced through vegetative reproduction).
· Common among the vegetatively propagated crops where natural recombination is impossible. Eg; mango. orange, potato, banana, sugarcane, turnip, citrus etc.
· Common among the vegetatively propagated crops where natural recombination is impossible. Eg; mango. orange, potato, banana, sugarcane, turnip, citrus etc.
(c) Hybridization:
· The crossing of two plants of unlike genetic constitution is hybridization.
· It does not change the genetic contents of organisms but produces a new combination of genes.
· Hybridization produces strong offspring i.e. Heterosis or hybrid vigour.
· The crossing of two plants of unlike genetic constitution is hybridization.
· It does not change the genetic contents of organisms but produces a new combination of genes.
· Hybridization produces strong offspring i.e. Heterosis or hybrid vigour.
· However, after a few generations heterosis is lost.
· Process of obtaining hybrid by method other than the sexual method is parasexual hybridization.
· Protoplast fusion is somatic hybridization.
· Based on the nature and relationship between plant species involved in the cross-hybridization is following types:
Types of Hybridization
I) Intra-specific hybridization:
· Cross between plants of 2 different varieties of the same species.
· Also known as inter-varietal hybridization
· Useful for improvement of self-pollinated plants species.
II) Inter-specific hybridization:
· Cross is made between plants of 2 different species of same genera.
· Useful for both self and cross-pollinated crops to get new variety.
III) Intra generic hybridization:
· Cross is made between plants of 2 different species of same genera.
· Used to develop disease resistance, drought resistance, pest resistance varieties of crops.
IV) Intergeneric hybridization:
· Cross is made between plants of 2 different genera of the same family.
Examples:
· Raphanus ✕ Brassica = Raphanobrasicca
· Process of obtaining hybrid by method other than the sexual method is parasexual hybridization.
· Protoplast fusion is somatic hybridization.
· Based on the nature and relationship between plant species involved in the cross-hybridization is following types:
Types of Hybridization
I) Intra-specific hybridization:
· Cross between plants of 2 different varieties of the same species.
· Also known as inter-varietal hybridization
· Useful for improvement of self-pollinated plants species.
II) Inter-specific hybridization:
· Cross is made between plants of 2 different species of same genera.
· Useful for both self and cross-pollinated crops to get new variety.
III) Intra generic hybridization:
· Cross is made between plants of 2 different species of same genera.
· Used to develop disease resistance, drought resistance, pest resistance varieties of crops.
IV) Intergeneric hybridization:
· Cross is made between plants of 2 different genera of the same family.
Examples:
· Raphanus ✕ Brassica = Raphanobrasicca
· Potato ✕ Tomato = Pomato
· Sugarcane ✕ Sorghum = Sorghumcane
Based on types of parents, it may be
· Monohybrid cross (AA × aa)
· Dihybrid cross (AABB × aabb)
· Trihybrid cross (AABBCC × aabbcc)
· Multiple cross (A × B = AB, C × D = CD; AB × CD)
· Back cross or Test cross (Aa × aa)
· Monohybrid cross (AA × aa)
· Dihybrid cross (AABB × aabb)
· Trihybrid cross (AABBCC × aabbcc)
· Multiple cross (A × B = AB, C × D = CD; AB × CD)
· Back cross or Test cross (Aa × aa)
Process of Hybridization
(i) Selection of plant
· Of the two-parent selected, one should be a well-adapted and proven variety in the location and the other variety should have the characters that are absent in the first parent.
(ii) Cultivation and selfing to get a Homozygous parent.
(iii) Emasculation before anthesis
· Removal of stamens or anther or killing the pollen grains of a bisexual flower without affecting the female reproductive structure is emasculation.
(i) Selection of plant
· Of the two-parent selected, one should be a well-adapted and proven variety in the location and the other variety should have the characters that are absent in the first parent.
(ii) Cultivation and selfing to get a Homozygous parent.
(iii) Emasculation before anthesis
· Removal of stamens or anther or killing the pollen grains of a bisexual flower without affecting the female reproductive structure is emasculation.
· It is done to prevent self-pollination & self-fertilization.
(iv) Bagging, tagging and labelling
· Bagging to prevent random cross-pollination.
· Tagging & labelling done in the bag.
(v) Artificial pollination
(vi) Harvesting and raising of F1 seeds.
(vii) Test of seeds and cultivation.
(viii) Production of F2 seeds.
(iv) Bagging, tagging and labelling
· Bagging to prevent random cross-pollination.
· Tagging & labelling done in the bag.
(v) Artificial pollination
(vi) Harvesting and raising of F1 seeds.
(vii) Test of seeds and cultivation.
(viii) Production of F2 seeds.
(d) Polyploidy:
· The organisms with multiple sets of genomes or basic chromosomes are polyploids like 2n (diploidy), 3n (triploidy), 4n (tetraploidy), 5n (pentaploid) etc.
· The polyploids shows gigantism with the increased size of plants and increased production of fruit.
· Naturally it is common in vegetatively reproducing seedless plants like banana, ginger, grapes etc.
· Odd-numbered ploids (triploids, pentaploids) are useless in the production of commercial seeds.
Method: In sexually reproducing plants, polyploids can be made by treating colchicines or by fusion of multiple male gametes with single egg cells.
Example: Development of bread wheat and triticale.
· The organisms with multiple sets of genomes or basic chromosomes are polyploids like 2n (diploidy), 3n (triploidy), 4n (tetraploidy), 5n (pentaploid) etc.
· The polyploids shows gigantism with the increased size of plants and increased production of fruit.
· Naturally it is common in vegetatively reproducing seedless plants like banana, ginger, grapes etc.
· Odd-numbered ploids (triploids, pentaploids) are useless in the production of commercial seeds.
Method: In sexually reproducing plants, polyploids can be made by treating colchicines or by fusion of multiple male gametes with single egg cells.
Example: Development of bread wheat and triticale.
(e) Mutation Breeding:
· Drastic inheritable changes in offspring.
· Mutation can be induced by using
(i) Chemical Mutagens: Hydrazines, Methyl methane sulphonate (MMS), Nitrous acid, Ethyl methane sulphonate (EMS)
(ii) Physical Mutagens: X-rays, Gamma-rays, Beta-rays, UV rays etc.
· Commonly used mutation in plant breeding is Point or gene mutation.
C. ANIMAL BREEDING:
Various methods of animal breeding are:1. In-breeding:
· Process of mating closely related individuals eg; Merino sheep (for producing fine wool), modern horse.
· It increases homozygosity.
· Continued inbreeding reduces fertility and productivity.
2. Out-breeding or Hybridization:
· Process of mating two unrelated individuals.
· It is practised for creating new breeds.
· It can be:
a) Outcrossing: between the same breed.
b) Crossbreeding: between different breeds.
c) Interspecific breeding: between different species.
Eg: Mule: male donkey and a female horse, Hinny: female donkey and a male horse, Liger: male lion and female tiger, Tigon: Female lion and a male tiger.
· It can be:
a) Outcrossing: between the same breed.
b) Crossbreeding: between different breeds.
c) Interspecific breeding: between different species.
Eg: Mule: male donkey and a female horse, Hinny: female donkey and a male horse, Liger: male lion and female tiger, Tigon: Female lion and a male tiger.
3. Artificial insemination:
· Process of introducing semen from a qualitatively stronger male into the vagina of a female.
· Most common method of producing new individuals at low cost from limited resources in remote areas of Nepal.
· The semen may be preserved either by freezing or by adding chemicals.
· Storage of semen is done in liquid nitrogen at -196 degrees centigrade.
· The credit for the first successful artificial insemination goes to Spallanzani in 1780.
· Process of introducing semen from a qualitatively stronger male into the vagina of a female.
· Most common method of producing new individuals at low cost from limited resources in remote areas of Nepal.
· The semen may be preserved either by freezing or by adding chemicals.
· Storage of semen is done in liquid nitrogen at -196 degrees centigrade.
· The credit for the first successful artificial insemination goes to Spallanzani in 1780.
(D) PLANT TISSUE CULTURE
· It is based on cellular totipotency given by Haberlandt (1902).· Experimentally explained by Steward et all.
· In tissue culture, a mass of cells or single cell is taken for experiment; known as Explant.
· The explant is provided with culture media containing sufficient nutrients.
· It gives the mass of undifferentiated cells known as a callus.
· In presence of shoot and root initiating hormones the callus starts organogenesis and ultimately produces plantlets.
· Meristem tissue culture is used to obtain virus-free plants.
· The fusion of protoplasm or somatic hybridization is protoplast culture.
· In protoplast fusion, protoplasts are fused by using a suitable agent called fusogen. The most common fusogen is polyethene glycol.
Micropropagations: The rapid multiplication or propagation of valuable crops in forestry, agriculture and horticulture through tissue culture is micropropagation.
· It is done under bacteria-free conditions.
· It involves following 3 steps.
(a) Multiplication of shootlets using cytokinin.
(b) Multiplication of rootlets using auxin.
(c) Transplantation.
(c) Transplantation.
(E) GENETIC ENGINEERING
· Science of adding, deleting or replacing genetic units instead of whole chromosomes in order to get heritable or permanent changes in organisms.· This technique is also known as Recombinant DNA technology or gene cloning.
Steps of Genetic Engineering
(i) Isolation of target genes:
· Target genes are isolated from the organism by using specific enzymes (restriction endonucleases, also known as molecular scissors or genetic scalpels).
(ii) Transfer of DNA
· Transfer of specific DNA from one organism to another.
· The isolated foreign DNA with protoplast is incubated by electroporation (by applying high electricity for microsecond separate DNA from protoplast) and DNA is injected into other cells by using a fine needle.
(iii) Cloning
· In this step the foreign DNA and plasmid DNA are joined with the help of enzyme DNA ligase to give rise to recombinant DNA.
· Hybrid or recombinant DNA, which when introduced into a living cell, replicates into multiple copies.
Major Types of Vectors
(i) Plasmids
(ii) Cosmids
(iii) Bacteriophages
Important Tools for Genetic Engineering
· Exonucleases
· Endonucleases
· DNA ligase
Application of Genetic Engineering
(a) Synthesis of vaccines
(b) Synthesis of hormones
(c) Synthesis of interferons and monoclonal antibodies
(d) Synthesis of antibiotic
(e) Eugenics
(f) Euthenics
(g) Genetic counselling
(h) Bio-fertilization
BIOFERTILIZERS
· The fertilizers of biological origin are called biofertilizers.· These are the micro-organisms that cause soil nutrient enrichment are considered to be biofertilizers.
· Biofertilizers are of 3 types
i. Nitrogen-fixing Bacteria;
ii. Nitrogen-fixing Cyanobacteria &
iii. Mycorrhiza (fungi).
1. Bacterial Biofertilizers:
(a) SYMBIOTIC BACTERIAL BIOFERTILIZERS
· Rhizobium leguminosarum and other species form mutually beneficial associations with root nodules of legumes.
· Root nodule consists of leghaemoglobin.
· The bacteria can convert the free nitrogen of the atmosphere into nitrates.
(b) FREE LIVING NITROGEN-FIXING BACTERIA
· Examples: Acetobacter (aerobic), Clostridium (anaerobic), Beijerinckia (aerobic), Rhodopsuedomonas, Rhodospirillium, Chromatium etc.
· Soil is enriched through exudation as well as the formation of nitrates after their death and decay.
2. Cyanobacterial biofertilizers (Blue-Green Algae):
(a) FREE LIVING NITROGEN FIXING CYANOBACTERIA
· Examples: Nostoc, Anabaena, Aulosira, Toly-pothrix, Plectonema fix nitrogen with the help of heterocysts.
· Aulosira is the best nitrogen-fixing blue-green algae in the rice field.
(a) FREE LIVING NITROGEN FIXING CYANOBACTERIA
· Examples: Nostoc, Anabaena, Aulosira, Toly-pothrix, Plectonema fix nitrogen with the help of heterocysts.
· Aulosira is the best nitrogen-fixing blue-green algae in the rice field.
(b) SYMBIOTIC NITROGEN FIXING CYANOBACTERIA
· Nostoc punctiforme, Anabaena cycadaceae, A. azollae found in Anthoceros, Cycas, Azolla, respectively.
· Azolla is good fertilizer for rice.
· Nostoc punctiforme, Anabaena cycadaceae, A. azollae found in Anthoceros, Cycas, Azolla, respectively.
· Azolla is good fertilizer for rice.
3. Fungi (Mycorrhiza):
· Mycorrhiza is the symbiosis of fungi with roots of higher plants.
(i) Ectomycorrhiza: E.g. in Eucalyptus, Oak, pine
(ii) Endomycorrhiza:
· Also called Vesicular Arbuscular Mycorrhiza (VAM).
· E.g. grasses, orchids
· Significant role in phosphate nutrition of plants.
· Mycorrhiza is the symbiosis of fungi with roots of higher plants.
(i) Ectomycorrhiza: E.g. in Eucalyptus, Oak, pine
(ii) Endomycorrhiza:
· Also called Vesicular Arbuscular Mycorrhiza (VAM).
· E.g. grasses, orchids
· Significant role in phosphate nutrition of plants.
Tissues and Organ Transplantation:
· Transplantation is defined as a process of substitution of damaged tissue or organ by a healthy one acquired from the donor.(a) Tissue Transplantation:
· Usually done with skin and part of bone e.g. in cases of a serious burn, broken bones etc.
Types:
(i) AUTOGRAFTS
· One’s own tissue is grafted to another part of the body; most successful type of transplantation.
(ii) ISOGRAFTS
· Grafting of tissue is done between identical / Homozygotic twins i.e. the donor and the recipient are genetically identical.
(iii) ALLOGRAFTS
· Transplantation occurs between individuals of the same species but with different genetic backgrounds.
(iv) XENOGRAFTS or HETEROGRAFTS
· Transplantation occurs between members of different species. E.g. Transplantation from pig to human being.
TISSUE REJECTION
· Due to the recognition of protein in the transplanted tissue or organs as foreign.
· It is due to cellular immunity.
Remedy for Transplant Rejection:
· Immunosuppressive therapy.
· Tissue matching before surgery.
· Monoclonal bodies against T-cells.
· X-ray irradiation of lymph node and bone marrow to inhibit the production of WBC.
· Due to the recognition of protein in the transplanted tissue or organs as foreign.
· It is due to cellular immunity.
Remedy for Transplant Rejection:
· Immunosuppressive therapy.
· Tissue matching before surgery.
· Monoclonal bodies against T-cells.
· X-ray irradiation of lymph node and bone marrow to inhibit the production of WBC.
(b) Organ Transplantation:
· Kidney, heart, lungs are transplanted in cases of organ failure.
· Transplantation of Cornea / Keratoplasty: The cornea of the donor should be removed within 6 – 12 hrs after death.
· Corneal transplantation is successful because the cornea has no blood supply.
· The main problem with organ transplantation is Graft rejection as it triggers the immune response in the recipient body. So they should use drugs called immunosuppressants after transplantation.
· To prevent tissue/organ rejection immunosuppressants like steroid drugs are provided. E.g. Cyclosporin
· First heart transplantation was done by Christian Barnard in 1967.
· Kidney, heart, lungs are transplanted in cases of organ failure.
· Transplantation of Cornea / Keratoplasty: The cornea of the donor should be removed within 6 – 12 hrs after death.
· Corneal transplantation is successful because the cornea has no blood supply.
· The main problem with organ transplantation is Graft rejection as it triggers the immune response in the recipient body. So they should use drugs called immunosuppressants after transplantation.
· To prevent tissue/organ rejection immunosuppressants like steroid drugs are provided. E.g. Cyclosporin
· First heart transplantation was done by Christian Barnard in 1967.
Test Tube Babies:
· The process of artificial insemination outside the female uterus is in-vitro fertilization (IVF) which is commonly called Test Tube Baby.· In IVF, an unfertilized egg or ovum is taken out from the lady and kept under an aseptic condition in a test tube.
· Sperms are taken from her husband (or donor) and mixed with the ovum for fertilization.
· After completion of fertilization, the zygote is formed and allowed to develop in vitro up to 32 celled stage.
· The embryo of 32 celled stage is transplanted to the female uterus.
· The first successful test-tube baby was born on 25 July 1978 named Louse Joy Brown.
· The first test-tube baby of Nepal is OM MANE TAMANG who was born in 20th Falgun 2061 in Om Hospital and Research Centre.
· In vitro fertilization technology was first pioneered in humans by Prof. Robert Winston.
· It was devised by Patrick Steptoe and Robert Edward.
· Surrogate mother is one who lends her uterus for implantation of the fertilized egg in case the original mother is unfit for the same.
Amniocentesis:
· The process of obtaining amniotic fluid from the womb of a pregnant woman is amniocentesis.· It is useful to test prenatal genetic disorders, sex determination of baby etc.
· In amniocentesis, a hypodermal syringe is passed to peripheral fluids of the foetus.
Antibiotics and Vaccines:
A. ANTIBIOTICS· These are the substances produced by micro-organisms that selectively suppress the growth or kill other micro-organisms at very low concentrations.
· The term “antibiotic” was coined by Selman A. Waksman.
· First synthesized antibiotic is Penicillin; which was extracted from Penicillium notatum (fungi) by Alexander Fleming (1928).
· Nowadays for commercial purposes, Penicillin is extracted from Penicillium chrysogenum.
· The most commonly used Antibiotics and their sources are:
Mechanism of Action of Antibiotics
(i) Inhibit cell wall synthesis. E.g. Penicillin
(ii) Cause leakage from the cell membrane. E.g. Amphotericin
(iii) Inhibit protein synthesis. E.g. Tetracycline, Chloramphenicol
(iv) Cause misreading of mRNA code and affect permeability. E.g. Aminoglycosides
(v) Interfere with DNA function. E.g. Rifampicin
(vi) Interfere with intermediary metabolism. E.g. Sulfonamides
Antibiotics |
Sources |
|---|---|
| Penicillin | Penicillium notatum |
| Streptomycin | Streptomyces griseus |
| Chloramphenicol | Streptomyces venezuale |
| Rifampicin | Streptomyces mediterranei |
| Tetracyclin | Streptomyces rimosus |
| Erythromycin | Streptomyces erythreus |
| Kanamycin | Streptomyces kanamycetius |
| Neomycin | Streptomyces fradiae |
| Gentamycin | Micromonospora |
| Cephalosporin | Cephalosporium acremonium |
Mechanism of Action of Antibiotics
(i) Inhibit cell wall synthesis. E.g. Penicillin
(ii) Cause leakage from the cell membrane. E.g. Amphotericin
(iii) Inhibit protein synthesis. E.g. Tetracycline, Chloramphenicol
(iv) Cause misreading of mRNA code and affect permeability. E.g. Aminoglycosides
(v) Interfere with DNA function. E.g. Rifampicin
(vi) Interfere with intermediary metabolism. E.g. Sulfonamides
Spectrum of Activity
1. Broad Spectrum Antibiotic
· An antibiotic that acts on a variety of pathogenic organisms.
1. Broad Spectrum Antibiotic
· An antibiotic that acts on a variety of pathogenic organisms.
· Examples: Tetracycline, Chloramphenicol
2. Narrow Spectrum Antibiotic
· An antibiotic that acts on selected or specific pathogenic organisms.
· Examples: Penicillin, Streptomycin, Erythromycin etc
2. Narrow Spectrum Antibiotic
· An antibiotic that acts on selected or specific pathogenic organisms.
· Examples: Penicillin, Streptomycin, Erythromycin etc
Types of Action
(i) Bacteriostatic
· Inhibiting growth of micro-organisms.
· Examples: Sulfonamides, Chloramphenicol, Tetracyclin
(i) Bacteriostatic
· Inhibiting growth of micro-organisms.
· Examples: Sulfonamides, Chloramphenicol, Tetracyclin
(ii) Bactericidal
· Killing pathogenic micro-organism.
· Examples: Penicillin, Cephalosporin etc.
Hybridoma
· It is the method of production of Monoclonal Antibodies.
· Monoclonal Antibodies are specialized antibodies produced only against a single antigen.
· It is the method of production of Monoclonal Antibodies.
· Monoclonal Antibodies are specialized antibodies produced only against a single antigen.
VACCINES
· Vaccines are the dilute suspension of Antigen, which is used to develop artificial immunity.· In 1796, the British Physician Edward Jenner introduced a vaccine against cowpox.
Various Types of Vaccines
1. Killed Vaccines
· Contains dead pathogenic organisms e.g. Typhoid vaccine, Cholera vaccine.
2. Toxoid
· Prepared by destroying the toxic (virulence) properties of toxin produced by the organism but retaining its Antigenic property.
· E.g. Tetanus toxoid
3. Attenuated living vaccines
· Pathogen is made weakened and non-virulent.
· E.g. Oral Polio Vaccine, BCG, Mumps, Measles, Rubella (MMR).
· Provides life long immunity.
4. Antibodies as Vaccine
· Provides artificial passive immunity.
· E.g. Anti-tetanus serum, Anti-rabies serum.
1. Killed Vaccines
· Contains dead pathogenic organisms e.g. Typhoid vaccine, Cholera vaccine.
2. Toxoid
· Prepared by destroying the toxic (virulence) properties of toxin produced by the organism but retaining its Antigenic property.
· E.g. Tetanus toxoid
3. Attenuated living vaccines
· Pathogen is made weakened and non-virulent.
· E.g. Oral Polio Vaccine, BCG, Mumps, Measles, Rubella (MMR).
· Provides life long immunity.
4. Antibodies as Vaccine
· Provides artificial passive immunity.
· E.g. Anti-tetanus serum, Anti-rabies serum.
Vaccines can also be categorized as follows:
1. First-generation vaccines
· Vaccines produced from microbes
2. Second-generation vaccines
· Vaccines produced from genetic engineering.
· E.g. Hepatitis B, Influenza, HIV, Herpes vaccines
3. Third-generation vaccines
· Vaccines produced synthetically.
1. First-generation vaccines
· Vaccines produced from microbes
2. Second-generation vaccines
· Vaccines produced from genetic engineering.
· E.g. Hepatitis B, Influenza, HIV, Herpes vaccines
3. Third-generation vaccines
· Vaccines produced synthetically.
Special Note for Entrance Exams:
· Raphanobrassica was the first artificial allotetraploid.
· Polypoids show Gigas effect. They are unable to cross with diploids regularly.
· Triticum aestivum is hexaploid.
· First transgenic Crop was tobacco.
· Pashmina is under the fur of Kashmiri goat.
· Narrow spectrum antibiotics are safer antibiotics.
· Anaerobic respiration is intracellular and intermolecular.
· Yeast respires both aerobically and anaerobically i.e, fermentation can be aerobic or anaerobic.
· Digitoxin is heart stimulator.
· Datura is a source of stramonium.
· Groundnut is used to extract margarine.
· Neem is used for the production of azadiractin.
· Vinblastine is obtained from Catharasithus.
· Polly and Molly are transgenic sheep while Dolly is the first animal to be cloned.
· Raphanobrassica was the first artificial allotetraploid.
· Polypoids show Gigas effect. They are unable to cross with diploids regularly.
· Triticum aestivum is hexaploid.
· First transgenic Crop was tobacco.
· Pashmina is under the fur of Kashmiri goat.
· Narrow spectrum antibiotics are safer antibiotics.
· Anaerobic respiration is intracellular and intermolecular.
· Yeast respires both aerobically and anaerobically i.e, fermentation can be aerobic or anaerobic.
· Digitoxin is heart stimulator.
· Datura is a source of stramonium.
· Groundnut is used to extract margarine.
· Neem is used for the production of azadiractin.
· Vinblastine is obtained from Catharasithus.
· Polly and Molly are transgenic sheep while Dolly is the first animal to be cloned.
High Yielding Points from Application of Biology
1. The organism which has the property of changing sugar into alcohol is Saccharomyces2. Human insulin is commercially obtained from E.coli
3. Transgenic animals are those which have foreign DNA in all of their cells
4. Antibiotic inhibits the growth of bacteria and fungi
5. Enzymes, vitamins and hormones can be classified into a single category of biological chemicals because all these help in regulating metabolism
6. Genetic engineering is possible because restriction endonucleases purified from bacteria can be used in vitro
7. Molecular scissors used in genetic engineering is a Restriction endonuclease
8. Utilisation of living organisms for producing material useful to human society is human as Biotechnology.
9. Hepatitis B and Herpes vaccines belong to Second-generation vaccines
10. Method of selection in plants showing vegetative propagation is Clonal selection
11. Emasculated flowers are bagged to prevent pollination
12. The most quickly available source of Nitrogen to plants are Nitrate fertilizers
13. The material of biological origin used for maintaining and improving soil fertility is green manure
14. The nitrogen-fixing bacteria associated with maize root belongs to the genus Azospirillum
15. The phenomenon of using a predator for controlling a pest is biological control
16. The tissue or plant part removed from the plant body for culture is called explant
17. The common mode of action of most insecticides is through the attack on the nervous system
18. The most common endomycorrhiza is Aspergillus niger
19. The most common type of tissue transplantation is skin transplantation
20. Antibiotics are produced by bacteria
21. The material of biological origin, which is used to maintain and improve soil fertility is green manure
22. Desired improved varieties of economically useful crops are raised by hybridization
23. Branch dealing with the production of superior varieties is called plant breeding
24. Amniocentesis is used for determining hereditary disease of embryo
25. A gene carried by recombinant DNA technology is cloned when its host bacterium divides by binary fission
26. Two bacteria found to be very useful in genetic engineering experiments are Escherichia and Agrobacterium
27. Ectomycorrhiza absorbs and stores nitrogen, phosphorus, potassium and calcium in the fungal mantle
Also, Read Notes of Other Lessons of Botany:
Also, Read our other Notes on the Application of Biology: