Biology for the Welfare of Mankind

During the past few decades research in the basic science of biology has yielded amazing knowledge. Application of biological knowledge has changed our lives in many ways. Humans are an integral part of the living world. Human beings have applied knowledge of biological science for the welfare of mankind. We will discuss few examples of historical and current endeavors.

Principles of Genetics

By using principles of genetics, new better varieties of wheat, rice, corn, chicken, cow and sheep have been developed poultry breeders have developed broilers for getting quick and cheap white meat. Genes of disease resistance and other desirable characters have been introduced into plants by using the techniques of genetic engineering. Plants having foreign DNA incorporated into their cells are called transgenic plants.

The plants can be propagated by cloning, using special techniques called tissue culture techniques etc. it is a technique in which a tissue is cultured to form a new plant e.g. A phloem tissue of an ordinary commercial carrot was removed and placed in a germ-free medium containing an adequate food supply, mineral salts, and growth substances. The cell developed into a complete carrot plant, which flowered and produced seeds.

Pesticides

The chemicals which are used for killing the pests are called pesticides. Many fungi cause diseases in plants which are controlled by using fungicides. Insect pests that cause a great loss of plants and plant yield are controlled by using insecticides. Use of pesticides is harmful to animal life including human beings. It is also an environmental pollution. Insects and fungi may become resistant to the chemicals used. Now some bacteria are being used as biopesticides, to control the pollution caused by pesticides.

Hydroponics

Plants are grown with their roots in dilute solutions of mineral salts instead of soil. This technique has been named as solution or water culture techniques. This water culture technique for growing plants with their root in a recirculating water solution is hydroponics. By this process exact and controlled amount of elements can be provided to plants. This method helps to determines inorganic nutrients required for the growth and development of plants.

Vegetable grown by hydroponics method

Food Preservation

Food is preserved by using different techniques like drying, freezing, sterilization, chemicals and heat. Killing of bacteria by heat is called pasteurization, developed by Louis pasture. Milk and milk products are preserved by this method.

 

Disease Control

There is a great success in the control of diseases. Three ways are generally taken to combat various diseases.

1. Preventive measures  

2. Immunization

3. Drugs treatment

 

Preventive measures

Prevention is better than cure.  Malaria can be prevented by using nets in doors and windows to ward off mosquitoes. By knowing the cause many diseases can be prevented easily. For example AIDS (Acquired Immuno Deficiency Syndrome) is caused by HIV (Human Immunodeficiency Virus). This disease spreads through free sexual contacts, through blood transfusion, by using contaminated syringes or surgical instruments. The best way of prevention from these diseases is to avoid the point of contact.                                                                               

Immunization

By immunization we are able to save millions of lives. Peoples use to die or suffer from diseases like tetanus, polio, hepatitis, whooping cough, measles; mumps etc. Immunization involves the using of vaccines. By vaccination many diseases have been controlled or even eradicated e.g. small pox. Polio has been effectively controlled in Pakistan by massive campaign like observing polio days for vaccination of children.

Drug treatment

a) Antibiotics

An antibiotic is a substance that is produced by an organism and inhibits or retards the growth of the microorganisms. Thousands of people used to die during war by infections. By using of antibiotics precious lives have been saved. Penicillin, streptomycin are the common examples of antibiotics.

b) Chemotherapy

With the increasing knowledge of biological science treatment of fatal diseases like cancer is possible. Chemotherapy is the treatment of infectious diseases or cancer by means of chemical compounds. Likewise cancer is also treated by radiation e.g. X-rays etc. The treatment by radiation is called radiotherapy. Repair of the defective gene is performed by isolating the normal gene and inserting it into the host through the bone marrow. This is called gene therapy.

immunization campaign

Cloning

A clone is an individual having identical genetic make-up like its parent. Cloning is possible with many plants because asexual propagation by cutting and grafting is relatively easy, and has been common practice. With this procedure and have orchard of uniform plants. Cloning in frog, mice, cows have been successful. In 1997 a sheep named Dolly has been cloned in Scotland which has been killed in early 2003 due to her illness.

During the process of cloning in animals the nucleus from a fertilized egg is removed. Then a nucleus from a cell of fully developed individual (donor) is inserted to the non-nucleated fertilized egg. The altered zygote is where it completes its development. The animal formed is genetically identical to animal whose nucleus was used. Thus by cloning multiple copies of a desired animal or genotype can be made.

the cloned sheep-dolly with her lamb bonnie

Biological Control and Integrated Disease Management

In biological control experiments, specialized predators are introduced into an environment in an attempt to reduce population of certain pests or disease causing organisms. For example to control the snake population in Islamabad mongoose have been introduced. As a result the number of snakes has reduced in Islamabad. World Health Organization (WHO) looks after the management, control and eradication of diseases all over the world. Some diseases have been irradiated e.g. smallpox. Many diseases are under control e.g. malaria. There is a ministry of health in federal Government and in provincial Governments, which looks after disease management in Pakistan e.g. vaccination against polio all over Pakistan. Diseases are also treated and control through Government Hospitals, dispensaries, private hospitals and clinics. Combating of disease by utilizing all methods as and when required and ensuring a participation of community in the program is called integrated disease management. This requires an awareness of the community about the severity of the problems, its causes and remedies.

Bacteria: Harmful and Beneficial Aspects

Bacteria, being microorganisms, can have both harmful and beneficial effects. Harmful bacteria are known to cause diseases in plants and animals, and can also have damaging effects in various other ways. For example:

a) Parasitic bacteria can attack plants, leading to diseases such as fire blight in apple and pear trees, and ring disease in potatoes, as well as the formation of crown galls.

b) Many human diseases are caused by bacteria, which can have detrimental effects on human health.

c) Some bacteria produce acids that can convert wine to vinegar, causing spoilage.

d) Bacteria can also cause the decay of wood, leather, fabrics, and other materials.

e) Bacterial decomposition can spoil food materials.

Examples of diseases caused by bacteria in humans include tuberculosis, which leads to swelling or nodule growth in the lungs or other parts of the body; tetanus, a condition characterized by prolonged muscle contractions, particularly in the jaw and other areas; cholera, which causes intense diarrhea; leprosy, a disease that attacks the nerves and leads to loss of sensation in the affected areas of the skin; typhoid fever, which involves the invasion of major organs in the body; meningitis, an inflammation of the membranes of the brain and spinal cord; sore throat, an inflammation of the respiratory tract; and whooping cough, an infection of the respiratory tract that causes periodic spasms of the larynx followed by a long, growing inspiration.

 

Methods for Controlling Bacterial Food Spoilage

There are several methods that can be employed to control food spoilage caused by bacteria, including:

Sterilization: This process involves killing microorganisms, including bacteria, by heating food to temperatures ranging from 12 to 126°C under pressure for 12 to 90 minutes.

Pasteurization: This method involves heating food to a temperature that is sufficient to kill nonspore-forming bacteria, such as milk, which is pasteurized by heating it to 71°C for 15 seconds or 62°C for 32 minutes. This process does not alter the taste of the milk.

Low Temperature: Food can be preserved for several days by keeping it at temperatures ranging from 10 to 15 degrees Celsius, as is commonly done with eggs, milk, vegetables, cheese, and meat.

Freezing: Food can be frozen at temperatures ranging from -10 to -18°C for several weeks to several months, as is often done with meat and vegetables.

Drying: The growth of bacteria can be inhibited by adding preservatives, such as acids to lower the pH, salt or sugar to increase their content and reduce the available water for bacterial growth, and chemicals like potassium metabisulphite. This method is commonly used to preserve pickles, candies, jam, and bread.

Radiation: Food can also be sterilized by exposing it to gamma radiation, as is done with meat and potatoes.

In conclusion, bacteria can have both harmful and beneficial effects, and their harmful effects can be controlled through various methods to prevent food spoilage and diseases in humans and plants.