Microbes – Friend or Foe
Approximately 4 billion years ago, even before the era of gigantic reptiles, the first form of life appeared on Earth. A prokaryote – a unicellular organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle.
It was a time when the earth was not a welcoming place. With no ozone layer to filter out ultraviolet sunlight, the atmosphere was full of toxic chemicals from various volcanic eruptions and the continuous barrage of objects from space to earth. Prokaryotes survived despite Earth being a terrible host and continue to do so to this day. Prokaryotic organisms like bacteria and archaea still thrive in extreme habitats from boiling geothermal vents to frozen Antarctica.
Like all living and non-living things, human beings have been in constant contact with micro-organisms. However, it took centuries for us to become aware of their presence. Though Robert Hooke was the first person to observe the presence of microorganisms, Antony van Leeuwenhoek is known as the father of microbiology for his most celebrated contribution – the microscope. A merchant by profession, Leeuwenhoek was fascinated by lenses in his childhood. Throughout his life, he crushed an enormous amount of glass to make lenses, ultimately leading to his invention of the microscope, through which Leeuwenhoek observed microscopic organisms that he named ‘animalcules.’ He was also the first person to describe fungi, bacteria, and protozoa accurately.
After Leeuwenhoek, for many years microbiology did not evolve as a field of study as scientists continued to debate over a phenomenon known as the genesis of life. The phenomenon stated that life forms like worms and grubs appear from non-living matter like beef broth. Francesco Redi and Lazzaro Spallanzani were the two scientists who showed the world that if broth is covered, maggots cannot infect it.
Later in the 1800s, a scientist named Loius Pasteur broke many beliefs, when he showed the world the influence of bacteria in souring wine and dairy. With his Germ Theory, Pasteur stated that microorganisms were the cause of all human infectious diseases. Pasteur failed to prove his theory but was later proved right by Robert Koch. In his experiments with anthrax bacilli and mice, he showed that mice suffer from anthrax when they are injected with the bacilli.
Koch’s discovery was a revolution as many scientists around the world started working on different diseases. Their efforts collectively resulted in a new pathogen being added to the list every month. Those were the days when human mortality rate was higher than the birth rate. Notorious epidemics like black death, Spanish influenza, malaria, took a rampant toll on humanity. This made people think that microorganisms are nothing but tiny monsters whose sole purpose was to destroy humankind!
However, even today, when we know so much more about the positives that microbes bring to our lives, we’re still only scratching the surface of our understanding.
While on the one side, there are microbes geared to attack our bodies, on the other, there are microbes on our body prepared to protect us against those attacks. When a baby is born, millions of bacteria stick to her body forming an invisible envelope – the commensal or normal flora of human body. Throughout our lives, microflora on our body synthesize a range of chemicals, enzymes, acids, proteins and more importantly, they act to protect us from many invading pathogens. Our body is at constant war with disease-causing agents, and our body flora is our defensive shield.
However, a shield alone is never enough to win a war; one must have a sword. In the battle against pathogens, antibiotics are our sword! Antibiotics are the compounds synthesized by fungi or bacteria that either kill growing infection or inhibit them from spreading.
I have always been fascinated that the discovery of this revolution in medicine was a mere accident. One fine day in 1928, Sir Alexander Fleming returned to his laboratory from a family vacation. In one of his experimental Petri dishes, Sir Fleming saw something unusual – a dead zone of bacteria surrounding a fungal zone. His investigations led him to conclude that the fungi released some chemicals that resulted in the death of bacteria. The compound he accidentally discovered is nothing but penicillin.
Penicillin was the first discovered and purified broad-spectrum antibiotic that can be used against infections in many parts of the body, including the mouth and throat, skin and soft tissue, tonsils, heart, lungs, and ears. Penicillin was named ‘Wonder Drug of WWII’, as it saved millions of lives and prevented many amputations during the war.
What started with Penicillin led scientists to the discovery of hundreds of new antibiotics. Today we have a vast range of antibiotics like sulphonamides, cephalosporin, tetracycline etc. which cure all sorts of major infections.
But with time, and overuse of antibiotics even for minor infections, pathogens developed drug resistance and became immune to stronger and stronger antibiotics. Infections have become more dangerous and life-threatening as they do not respond to therapy. One of the reasons for pathogens developing drug resistance is a phenomenon known as Quorum Sensing.
In catastrophic conditions, say antibiotic actions, chatty bacteria come together and release chemicals that help them to communicate with each other. In response to these chemicals, they form a tough intermediate structure that enables them to withstand unfavourable environmental conditions. This bacterial layer known as biofilms is responsible for the destruction of water reservoirs as well as posing a threat to life in patients.
Recently scientists have developed techniques to use quorum sensing as well as biofilms for various applications such as cancer detection, biocontrol, prevention of bio-fouling diagnostics and therapeutics.
The power of microbes extends to the plant world too. Microbes are ubiquitous: they are present in air, water and soil. Microbes from the soil nourish plants by building a healthy eco-system around their roots. Through various biochemical activities, they fix atmospheric nitrogen in the soil which is crucial for plant development. Phosphorus is another essential element required for the nutrition of plants. Bacteria and fungi from the soil convert phosphate from soil and make it consumable for plants.
Furthermore, certain bacteria and fungi establish a symbiotic association with plant roots, in which they colonise the roots. This helps plants to absorb more nutrients from the soil and provides microbes with shelter and waste products as their food.
With advancing technology, scientists have developed fantastic products like bio-fertilizers and bio-pesticides. These crop-specific products not only help with higher yield but provide crops with immunity from notorious pests.
All over the world farmers are facing the problem of infertile soil. With the advent of chemical fertilizers, it was like hitting the mother lode – higher yields. This led to the uncontrolled use of chemicals as pesticides and fertilizers. Over the years, these synthetic chemicals accumulated in the land and degraded its quality. This affected everything – from plants to animal life to humans. DNA damage, loss of variety, the emergence of cancer are just some ways in which we continue to pay the price.
Just like our phones, Mother Earth needs a restore button, and that button is bioremediation. Through bioremediation, the quality of polluted lands and water bodies can be restored to its original state with the help of the microbes.
Microorganisms can break down complex organic compounds, like hydrocarbons into simpler products, i.e. carbon dioxide and water. A little help from genetic engineering and biotechnology can boost the degrading ability of microbes. When such modified microbes are applied to polluted water bodies or agricultural lands, they degrade chemicals present in the surrounding and ultimately restore them to the natural state.
Just like our Indian gods, microbes are present everywhere! From our health to growing pollution, microorganisms have better solutions for most problems posed to mankind. A debate over companionship with microbes turns meaningless when we see their potential to provide sustainable solutions that guarantee us and generations that follow us a better future.
This post first appeared on LinkedIn