Deadly diseases like TB, typhoid, anthrax, cholera etc are caused by bacteria. So, our natural instinct would be to look upon all bacteria as extremely dangerous organisms. But there are innumerable bacteria that have been identified as having beneficial characteristics.

We are not entirely human. Scientists around the world assert that many bacteria are present in our body taking care of us. The microbes are important to body functions like digestion and immune system.

We are somehow like an amalgam, a mix of bacteria and human cells. Bacteria, native to our body may prove clues to our diseases, nutrition, obesity and how well drugs work on us. Scientists have long known that bacteria start colonize the intestine shortly after birth and adults carry nearly hundred trillion microbes belonging to more than 1000 species. They help us to digest much of what we eat. They also synthesize vitamins that we cannot. Steven R. Gill sequenced the DNA of human faeces. A surprising amount of it came from the microbes "of the entire DNA sequenced in the material only one to 5% was not bacterial. The donors have not taken any antibiotic for a year, the latter are known to disturb the bacteria.

Probiotic Bacteria: For breakfast we take, most of the items are fermented by bacteria. These types of microbes are known as probiotic because they are protective as well as therapeutic against a range of disorders. The bacteria bring about desirable alterations in food quality and fermentation preserves and predigests the food. Probiotic food consumption has been found useful in the treatment of various types of diarrhea, lactose intolerance, allergy and cancer. These are not destroyed by the acid present in the stomach or the enzymes in the intestinal tract.

Probiotics can also enhance both the specific and non-specific immune response of the body, possibly by activating macrophages, natural killer cell activity and the levels of immunoglobulins. The microbes may be useful to prevent alcohol-induced liver damage. Oral probiotic could be superior to conventional therapy in the treatment of hepatic encephalopathy, a common and dreaded compilation of liver disease.

Antibiotics are the biggest culprits killing the probiotic bacteria, hence doctors recommend probiotic supplements alongwith antibiotics. A cup of yogurt has more live beneficial microflora than a cup of cooked fermented food. Lactobacillus (in milk) may suppress the growth of Helicobacter pylori, which causes peptic ulcer. The microbes also promote bone density by absorption of calcium and magnesium from the intestine.

In medicine: For many years, insulin required by type I diabetic people come from the pancreatic cells of cows and pigs. In recent years, due to advancement in biotechnology, the source of insulin has now been replaced with bacteria. Apart from that, other valuable drugs such as human interferon, bovine growth hormones have also been produced in genetically engineered bacteria.

In Environment:
There are a few bacteria that clean up the environment by removing many pollutants. Two such microbes are Rhodopseudomonas palustris and Leptospirillium ferrooxidans. Prof. Caroline Harwood a microbiologist at Iowa University studied the versatile bacterium Rhodopseudomonas palustris. The microbe cleans industrial effluents like chlorine, carcinogenic benzene and its derivatives, and CO2 responsible for global warming. When light is shone on the bacterium it produces ammonia by fixing atmospheric nitrogen. We know well that ammonia increases soil fertility to enhance crop yields. In this process we have another reward from the microbe. In addition to ammonia, it produces hydrogen that could be used as biofuel.

Researchers have found R. palustris to have five different kinds of light harvesting proteins. It mixes and matches them to get maximum energy from the available light. On the other hand, most bacteria have only one light harvesting protein.

Leptospirillium ferooxidants were developed by scientists at the US department of Energy. These microbes have been used to purify coal. The microbes were isolated from geothermal locations in the South Pacific and North America by using a technique called 'challenge biosynthesis nutritional stressing'.

Anticancer Drug through bacterium: A genetically modified form of bacterium, Pseudomonas syringae pv. syringae (Pss), infects numerous plants and could help uncover a class of anticancer drugs for humans. The bacterium causes a brown spot on the common bean leading to the formation of a compound called syringolin-A which boosts the microbe's virulence. Earlier studies have shown that syringolin-A has the capacity to shrink certain cancers, opening the possibility that this and similar molecules might be developed as new cancer therapies.

Rain making bacteria: These are those bacteria that cause frost damage on plants and can also help clouds to produce rain and snow. Air-borne bacteria, fungi, and tiny algae do the similar job. Unlike mineral aerosols, living organisms can catalyze ice formation even at temperatures close to 0ºC.

In Industry: Bacteria, fungi and algae have also found implications in the production of single cell protein; the same is supplied as supplements for human or animal food.

In conclusion, bacteria have been widely acknowledged for their importance to mankind in recent years. Bacterial exploitation leads to the manufacture of novel products owing to their property of production of secondary metabolites and enzymes. Our next aim will be to gain an insight regarding the immunological properties of bacterial cell wall, in order to open a window for new pharmaceutical products.

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Written by Debasis Sahu and Shikha Sharma