Useful role of Bacteria In Medicine
(i) Production of antibiotics
1. Antibiotic – An antibiotic is a chemical substance produced by a living organism which can stop the growth of some disease producing bacteria and fungi e.g. streptomycin, chloromycetin, tetracycline, penicillin etc.
2. Penicillin is the first produced antibiotic discovered by Alexander Flaming & the source organism for this antibiotic is a mould (fungus) Penicillium notatum.
3. Antibiotic streptomycin was discovered by Selman Waksman by the means of a bacteria Streptomyces griseus.
(ii) Production of serum
1. Serum – Blood plasma without fibrinogen containing antitoxins for a particular pathogen & used as a preventive measure against bacterial invasion.
2. To prepare serums a small dose of bacterial toxin is introduced in the blood of a healthy animal (horse or cow).
3. The body of the animal produces antitoxins to neutralize the effect of toxin.
4. After injecting the animal several times the blood of the animal is taken out.
5. On chilling the blood the serum separates out as straw colour liquid from the clotted blood.
1. Any germ or germ substance introduced in to the body for developing resistance to the particular disease.
2. On injecting germ or germ substances in the body, the person gets the disease in mild form and his body gets stimulated to produce antitoxins which provide immunity against the any future attack of the disease.
3. Some common vaccines are killed bacteria for TAB vaccine for typhoid & living weakened germs BCG vaccine for tuberculosis.
1. Extracts of toxins of the particular bacteria, for producing immunity against diphtheria & tetanus.
Role of bacteria in agriculture
1. Nitrogen Fixing Bacteria - In small nodules on the roots of leguminous plants a special category of bacteria (Rhizobium)are found which converts atmospheric free nitrogen in to soluble nitrates . These nitrates are used by the host plants. Such bacteria are called nitrogen fixing bacteria.
2. Nitrifying Bacteria - Nitrates in the soil which are essential for protein synthesis, are replenished in the soil by bacteria through the process of nitrification according to following steps -
(a) Nitrogenous waste from animals & dead remains of plants & animals get converted in to ammonia by some bacteria.
(b) Ammonia is then converted in to ammonium compounds.
(c) Ammonium compounds first converted in to nitrites by bacteria Niteomonas
(d) Nitrites are then converted in to nitrates by bacteria Nitrobacter
3. Denitrifying Bacteria – Some bacteria present in to soil break down soil nitrates to release nitrogen gas, theses are called denitrifying bacteria.
Role of bacteria in industry
1. For producing different flavours of tea called tea curing
2. For breaking soft perishable parts of animal skin to make leather called leather tanning.