We often call microorganisms ‘germs’ giving them the connotation of being something bad; but in reality, there are many microorganisms that benefit man and the environment we live in.
Differentiating between the good and bad is not always that straight forward; but it is important to recognize the benefits of microorganisms just as much as to recognize the problems they create. This is because even though bad microorganisms can be controlled by killing all microorganisms – to kill all would involve also removing microorganisms that we need.
Good Things Microorganisms Do
Microorganisms are responsible for the following:
- Facilitating digestion of food we eat, and food that nourishes all animal and plant life.
- Keeping us healthy: Good microbes protect us from pathogens by colonising our bodies - so that there is less room for bad microbes to invade our bodies. They can also boost our immune system helping us fight diseases such as cancers and protecting us against auto-immune diseases. They digest our food and help us to stay slim by producing chemicals in our bodies that improve our metabolic rate. They detoxify our system and metabolise toxins that might otherwise be harmful to us.
- Helping plants grow - Legumes form special nodules on their roots. In these nodules live Rhizobium bacteria which take up freely available nitrogen gases from the air and use it for their own growth. In addition, the bacteria convert large amounts of atmospheric nitrogen which they do not need into a form that the legumes can use. The bacteria provide large quantities of nitrogen for the legume while the legume provides a home and some nutrients for the bacteria. This sort of mutually helpful partnership is called a symbiotic relationship.
- Some beneficial fungi grow in a symbiotic relationship with the root cells of higher green plants. This is termed a mycorrhizal association. Roots of many cultivated plants including corn, soybeans, cotton, tobacco, peas, red clover, apples, citrus, pines, eucalypts and others have mycorrhizal relationships with higher fungi. The mycorrhizae appear to be highly beneficial for optimal growth of many plants. Establishing proper mycorrhizal fungi with cultivated plants offers a great potential for improved plant growth. Some mycorrhizae form a kind of sheath around the roots sometimes giving a hairy or cottony appearance. The plant roots transmit substances to the fungi and the fungi aid in securing and transmitting nutrients and water for the plant roots. Because they provide a protective cover, mycorrhizae increase the plant's tolerance to drought, high temperatures, infection from disease fungi and even to extreme soil acidity and are able to improve the efficiency of nutrient absorption. Mycorrhizae grow and develop best in a well aerated soil in a sunny position. High application of nutrients tends to inhibit their development. The greatest growth responses to mycorrhizae are likely to occur in highly weathered soils which are low in basic cations and are low in phosphorus.
- Producing special affects like variegation in plants (viruses).
- Decomposing waste materials including human effluent, all sorts of plant and animal waste, cleaning up oil spills and decomposing other things such as plastics (Note -even though decomposition of plastics may be slow, it does nevertheless occur) and nylon.
- Making biofuels such as ethylene by consuming and decomposing waste (including human waste) plus toxic waste and turning it into electricity. Geobacter bacteria even consume radioactive waste (immobilising materials such as uranium).
- Metabolise methane - methane is produced through all sorts of industrial activity and some bacteria can use copper (a potentially toxic heavy metal) from the environment to metabolise methane this may be one answer to green-house gases and global warming.
- Producing wine, beer, cheese, pickles, yoghurt and many other important foods.
Human Health Benefits
Antibiotics and vaccines are the most important contribution of microbiology to the pharmaceutical industry. In times past antibiotics were the products of microbial metabolism but more recently genetic manipulation has played an important role in the production of enhanced drugs.
One important role of microbiology in pharmaceutical laboratories is the prevention of contamination and spoilage of drugs and other pharmaceutical products through quality control.
For many years, the insulin required by diabetics was extracted from abattoir animals (usually cows and pigs). The development of recombinant DNA sequencing, or splicing certain genetic material into other organisms, revolutionised—and continues to revolutionise—drug production. Today, diabetics use human insulin, manufactured in a lab by bacteria. Antibiotics and vaccines are also produced in this way.
Antibiotics were introduced in the 1940s with the manufacture of penicillin. Since then many other antibiotics have been manufactured. In the 1940s the discoverer of streptomycin, Selman Waksman, defined an antibiotic as “a chemical substance produced by microorganisms which has the capacity to inhibit the growth of bacteria and even destroy bacteria and other microorganisms in dilute solution”.
Only a small percentage of known antibiotics has been brought to market. This is because many antibiotics are either too toxic for therapeutic use or are not of greater benefit than the antibiotics already available on the market.
As pathogens develop resistance to antibiotics, industrial microbiologists are continuously looking for new antibiotics. They are also continuously looking for ways to make existing antibiotics more effective, by increasing the potency of antibiotics, improving therapeutic properties and making antibiotics more resistant to inactivation.
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