Data about trillions of bacteria swarming the skin and all over the human body sounds really scary. However, micro biologist Anne Maczulak emphasized that humans cannot live without bacteria.
The author of the book ‘Allies and Enemies: How the World Depends on Bacteria’ explains that humans cannot live without bacteria. Most humans study bacteria in the context of disease.
This makes people tend to think about the dangers posed by these bacteria. “It’s a challenge to think about how bacteria help humans because of tendencies to go beyond complex, one-off processes,” says Maczulak.
In the soil and sea, bacteria are major players in the decomposition of organic matter and the recycling of chemical elements such as carbon and nitrogen that are necessary for human life.
Since plants and animals do not produce the molecular nitrogen that humans need to live, soil bacteria and cyanobacteria (blue-green algae) play an indispensable role in converting atmospheric nitrogen into ammonium or nitrate.
Both are forms of nitrogen that plants can absorb to produce amino acids and nucleic acids, the building blocks of DNA. Humans eat the plants and reap the benefits.
In addition, bacteria also play the role of cycling another important substance for human life, namely water. In recent years, scientists from Louisiana State University have found evidence that bacteria represent the many tiny particles that cause clouds to accelerate, dropping snow and rain.
Outside and inside the human body, bacteria still offer other benefits. In the digestive system, bacteria help digest food, such as plant fiber, which humans cannot handle very well.
“Humans get more nutrients from food thanks to bacteria,” says Maczulak. According to Maczulak, bacteria in the digestive system also provide vitamins that humans need such as biotin and vitamin K and other main sources of nutrients.
Experiments on rabbits showed that animals raised in a sterile environment without bacteria suffered from malnutrition and died young. According to Maczulak, outside the body, a “bacterial forest” on the skin (according to New York University, there are 200 separate species of bacteria in the normal person) dominates the skin’s environment and its resources and keeps other bacteria out.
Inside or outside the body, bacteria prove to be an important part of the development of the immune system. According to microbiologist Gerald Callahan at Colorado State University, bacteria, whether benign or harmful, prime the immune system to respond to invading pathogens at a later date.
Callahan’s study, published in the New EnglandJournal of Medicine, also shows that children who are protected from bacteria have a higher chance of developing asthma and allergies. That doesn’t mean that beneficial bacteria can’t be harmful.
Usually, beneficial bacteria and harmful bacteria are mutually exclusive, Maczulak said. However, their actions overlap, particularly in the bacteria that inhabit the body. “Staph bacteria being an example, they are all over the skin,” he says.
A Staphylococcus Aureus colony living on the arm may work together, attacking the intruder without harming the body but if the immune system is compromised, these bacteria can go berserk and cause infection.
The number of bacterial cells in the human body is estimated to be 10 times greater than the number of human cells. “This has led many scientists to describe humans as more like bacteria than humans,” Maczulak said. Sounds a little scary, “But it helps you visualize how big a role organisms play.”
