Parasites, bacteria and viruses have been the scourge of humanity throughout its history, but also changed it and influenced our evolution. Parasites have helped our immune system to gain the necessary stimulus and make money, and humble bacteria have completely and completely defined the rules of life on this planet. Sometimes it seems that we humans are just toys in their hands. It is believed that aliens from distant worlds may not understand who is the real owner on this planet. In any case, microorganisms do incredible things to help humanity.
African viruses help us survive
Thanks to science, viral molecular genetics, we now know little about those who infected us on our evolutionary path, as well as the fact that these hitchhikers constantly helped us. For example, the evolutionary pressure they put on our immune system made us as resilient as they are today. In addition, viruses could play a role in the loss of specific receptors that were once located on the surface of our cells; infectious agents could cling to them and use them to cause disease. Having rid the human body of this source of disease, the viruses have created safer conditions for themselves. Won all.
In addition, they may have played a role in the fact that among the competing hominid species, Homo sapiens took the first place. While our species was developing, various diseases and parasites attacked genetic diversity and weed out unsuitable models. As soon as the first Homo sapiens left the continent, he brought with him his infectious colonies and parasites.
Viral parasites have spread to other hominids like Homo neanderthalensis (Neanderthals), who did not have a previously developed system of protection against new diseases and the structure of the nose, which was less effective in filtering air and keeping new viruses. Other hominid species became extinct because they were not adapted to survive in conditions in which harmful microorganisms could survive. Modeling showed that if Neanderthals had a mortality rate of at least 2% higher than people, it would be enough for them to become extinct after 1,000 years of competition. Although diseases, of course, were not the only factor, they played a large role.
Most models of the evolution of human diseases claim that most of them evolved during the Neolithic era, after man moved from Africa and the population increased. Thus, there is some evidence of this selective viral pressure. Many of these early viruses were so successful that their genes literally became part of our DNA. For example, the human genome contains bornavirus, which became part of it about 40 million years ago. In total, scientists have identified about 100,000 elements of human DNA that could be part of viruses, the so-called junk DNA. The viruses that make up most of our junk DNA are called endogenous retroviruses.
Modern use of leeches and larvae
For thousands of years, the European leech (Hirudo medicinalis) has been used in medicine for bleeding and treating a wide range of diseases: from hemorrhoids to ear infections. The practice goes so far back in time that Egyptian painting is 1500 BC. er depicts their use. Although some countries have never stopped their use, in many countries the practice has nevertheless faded due to the development of microbial theory.
Nevertheless, in the 70s and 80s the leeches returned. Cosmetic and reconstructive surgeons have found that they can be effectively used for bleeding from swollen faces, black eyes, limbs, and other things. They are also useful in reattaching small parts of the body, such as ears and skin patches, because they suck blood, which can coagulate and interrupt the healing process. Leeches save people from amputation and can even relieve pain in osteoarthritis. Even vets sometimes use them.
Larvae, on the other hand, are natural cleaners. They are great for corroding dead or infected flesh, revealing healthy tissue in the process of so-called wound debridement. They also proved to be an effective treatment for ulcers, gangrene, skin cancer and burns.
The larvae and leeches are so effective that in 2010 they became the first “living medical products”, paving the way for an entire industry called biotherapy.
Parasites and the immune system together protect us from allergies
Researchers studying the effects of gastrointestinal parasites came up with an incredible theory: after the parasites first colonized our gastrointestinal systems, they developed the ability to suppress our immune system for a million years. At the same time, our own bodies evolved to partially offset the effect.
The most interesting part is that as soon as the parasites and harmless microorganisms present in water and soil were largely removed from their habitat within us in the process of developing civilization and medicine, our immune system actually over-compensated for this loss, which led to allergies and increase the chances of asthma and eczema.
This “old friends” hypothesis (sometimes referred to as the “hygienic hypothesis”, although it is much more complicated) has received much support in recent years, as we discover new facts about how microorganisms have helped us survive for thousands of years.
The first hypothesis of old friends was suggested by Graham Rook of University College London 2003.
Some people bring the hypothesis of old friends to its logical conclusion: if the removal of parasites from society leads to health problems, you need to bring them back. In 2008, John Fleming, a professor of neurology at the University of Wisconsin, conducted a clinical study in which he infected some patients with multiple sclerosis with parasitic worms and tested the effectiveness of this method. Within three months, in patients who had an average of 6.6 active foci among the nerve cells of the brain, the level of the disease fell about two times. When the test ended, the number of foci returned to 5.8 in two months.
Parasitic therapy is still in the experimental phase, and, most likely, currently has negative consequences that outweigh the positive ones. Currently, medical commissions classify worms as biological products that cannot be sold until their safety has been proven. Only one species, Trichuris suis, has been approved for testing a new drug.
Virotherapy
One of the most interesting and promising branches of medicine in recent decades is virotherapy, a biotechnological technique of reprogramming viruses for the treatment of diseases. In 2005, researchers at the University of California at Los Angeles announced that they had turned one of their worst enemies into a cancer killer when they reprogrammed a modified HIV strain to track down and destroy cancer cells. At about the same time, researchers at the Mayo Clinic in Rochester, Minn., Modified the measles virus to do the same.
The technique is similar to that used to breed genetically modified plants, only the virus is used as a gene carrier. It has long been recognized as the most effective means of gene transfer. This system is used to produce beneficial proteins in gene therapy and has great potential for treating immunological diseases such as hepatitis and HIV.
Back in the 1950s, it became known that viruses have potential for treating cancer, but the advent of chemotherapy slowed down progress in this direction. Today virotherapy turns out to be a very effective means of fighting against tumors, since it does not damage healthy cells around it. Clinical trials of oncolytic virotherapy showed low toxicity and promising signs of efficacy. In 2013, a drug called TVEC became the first virus-based medicine to fight late-stage tumors.
One of the biggest problems facing the researchers is the issue of delivering the virus to where it will work best, before the body recognizes the intruder and “raises troops” in it.
Using viruses to treat bacterial infections
Bacteriophages are viruses that prey on bacteria. First discovered by Frederick Creative in 1915 and Félix D'Herel, two years later, they have been used to study many aspects of viruses since the 1930s. They are especially common in the soil that many bacteria choose as their home.
Since phages violate the metabolism of bacteria and destroy them, it has long been recognized that they can play a role in the treatment of a wide range of bacterial diseases. But due to innovations in the field of antibiotics, phagotherapy was again placed on the shelf until the growth of bacteria resistant to antibiotics aroused heightened interest in this area.
Certain types of phages are usually effective only against a small range of bacteria, or even one specific species (primary host), which was initially considered a disadvantage. But since we learned more about the beneficial aspects of our natural flora, the disadvantage turned into an advantage. Unlike antibiotics, which usually kill bacteria indiscriminately, bacteriophages can attack disease-causing organisms without harming our natural flora.
While bacteria can develop resistance to both antibiotics and phages, the development of new strains of phages will take only a few weeks, not years. Phages can also penetrate the body, find a target, and when the bacteria are destroyed, stop reproduction and die out soon.
Vaccines
Since the 1790s, when Edward Jenner developed the world's first smallpox vaccine, using a less virulent strain of vaccinia to vaccinate patients, this vaccine saved the lives of many millions of people. Since then, however, many other vaccines have been developed. Weakened or “live” vaccines use live viruses that have been weakened or modified to not cause disease, while inactive or “dead” vaccines contain dead microorganisms or toxins that are commonly used against bacterial infections. Some vaccines, including subunits and conjugate vaccines, as well as recombinant and genetically modified vaccines, use only the infectious agent segment.
When the vaccine is injected, the pathogen begins to work, which is not enough to multiply in such a size as to cause disease. The body produces an immune response, kills the pathogen, or destroys the toxin responsible for the disease. The body's immune system now knows how to fight the disease and will remember if the pathogen enters the body again. In other words, scientists have figured out how to make a pathogen help its goal to protect against it. They even took several steps to develop vaccines for several forms of cancer and the hepatitis B virus (which causes liver cancer), human papilloma virus types 16 and 18 (which causes cervical cancer) and metastatic prostate cancer in some men.
Thanks to vaccines, several diseases were forced to virtually disappear. Smallpox remains the most famous example, but polio, which, though not completely destroyed, is in second place. Several other diseases can go away even now, if vaccines were not so difficult to deliver to underdeveloped countries.
Bacterial waste disposal
Some of the smallest and simplest creatures on Earth play one of the most important roles in saving lives. Bacteria destroy and recycle waste.
The dead remains of animals and plants, along with the excreta of all organisms, contain vital nutrients and stored energy. Without the ability to return these nutrients, the available sources would be quickly exhausted. Fortunately, many types of bacteria select these particular energy sources, breaking them up into their small molecules and returning them to the soil, from where they then re-enter the food chain.
In addition to this process, people found a lot of ways to use its analogues. Bacteria are used in wastewater treatment, industrial waste management and oil spills, leaked pharmaceuticals and wastewater. They are also useful in the development of aquatic farms, the fight against algae and dry closets. Researchers and engineers are constantly looking for ways to use bacteria. They may even be adapted for splitting plastic waste.
We would die without intestinal bacteria.
Until recently, people understood poorly (and little research has been done so far) that the natural bacteria that live in our intestines work with our immune system to suppress pathogens, produce vitamin K, stimulate peristalsis, and even digest our food. Without these bacteria, we would not be able to perform any of these functions and probably died.
The more we learn about beneficial strains of intestinal bacteria, the more we can incorporate this knowledge into a healthy lifestyle. After it was found that some intestinal bacteria can play a role in obesity, probiotics have become particularly popular. Probiotics are bacteria that replace fermented foods and are currently sold as supplements. Bacteria such as certain species of bifidobacteria can create a highly acidic environment in which less beneficial microorganisms cannot survive. Fatty foods and stress can also play a role in the health of our gastric flora, killing beneficial bacteria and allowing harmful bacteria that cause gas, bloating and increased intestinal permeability to develop.
Skin bacteria can be at the forefront of immunity.
At that moment, when you came out of the womb of your mother, you came under fire. They set up an ambush and in a matter of minutes colonized every inch of your skin. In principle, they are with you now. These are prokaryotes and other bacteria, and if it were not for the evolution that has been shoulder to shoulder with these microorganisms for millions of years, you would be dead soon after birth.
One of the most common skin bacteria is Staphlococcus epidermis. It is known that it plays an important role in the fight against Leishmania major, the cause of a dangerous disease called leishmaniasis, which gives rise to non-healing ulcers. A good bacterium causes an immune response called IL-1, which the body cannot produce on its own. These staphylococci have become an indispensable part of our existence.
The prokaryotes that inhabit the digestive tract also cover the entire outer surface of the skin. Along with the rest of our beneficial microflora of the skin, they became a part of us when they competed with less benevolent microorganisms for the right to live. Along with the immune cells of our skin, they protect us from pathogenic bacteria and pathogenic fungi that want to live in us. This allows our bodies to spend less energy, protecting our exterior, and focus more on things like fighting viruses and precancerous cells.
Although we still have a lot to learn from them and learn more about these beneficial bacteria, in the future skin bacteria will be used purposefully.
Life would not be without cyanobacteria
Cyanobacteria, or blue-green algae, are perhaps the oldest still-living species on Earth. Its fossils date back 3.5 billion years. These are single-celled bacteria that grow in colonies, and if they did not exist, there would be neither us nor any other form of life.
Cyanobacteria were the first photosynthesizers in the world. They used the energy of the sun along with chemicals in the first oceans and inert nitrogen in the atmosphere for food. As a waste product, they produced oxygen, which was poison for almost any other form of life at the time. For approximately 300 million years, all of these oxygen wastes have formed an atmosphere, as we know it, during the Archean and Proterozoic eras.
Sometimes, during the Proterozoic or early Cambrian period, these bacteria formed symbiotic relationships with some eukaritot cells, giving the cells food in exchange for stable conditions that could be called home. These were the first plants. The incredible event of endosymbiosis is still considered one of the most important in the formation of the first life.
Based on listverse.com
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