Bacteria are everywhere!
My favourite Zen story is when a question is asked of a Zen monk – ‘‘A house is on fire. What is the most important thing that you would save?’’ He replies – “I would save the fire.”
This story has stayed with me for 40 years teaching me to look deeper into what we consider valuable.
Let’s talk about the single tiniest living being on the planet – the bacterium, a tiny single cell being so small that millions live together and are collectively known as bacteria. A gram of soil contains about 40 million bacterial cells. A millilitre of fresh water usually holds about one million. Earth is estimated to hold at least 5 nonillion (54 zeros!).
A bacterium is a proper being. It can communicate, travel, multiply, generate energy, understand its environment. There are three types: ball shaped or cocci, rod shaped or bacilli, and spiral or spirilla. They are found everywhere – from your stomach to the Arctic ice and volcanoes, the bottom of the ocean to 30 miles up in the sky. Soil, plants, animals – all of us are walking mountains of bacteria.
Some of them are extremophiles, surviving in such toxic conditions or extremes of temperature where no other being can survive.
Bacteria are the first forms of life on this planet about 4 billion years ago. You are their descendants.
They were first attempted to be identified by Marcus Terentius Varro (Roman - 116 BC-27 BC) who suggested that disease may be caused by miniscule animals that floated in the air. They were finally identified by Antonie van Leeuwenhoek (Dutch 1632-1723) who made microscopes, with which he saw what he called animacules in 1676 (to be called bacteria 162 years later). He is known as the father of microbiology. Christian Gottfried Ehrenberg (German 1795-1876) introduced the term bacterium in 1838. Robert Koch (German 1843-1910) was awarded the Nobel Prize in 1905 for proving diseases were caused by bacteria. Paul Ehrlich (German - 1854-1915) won the Nobel prize for pioneering the use of stains to detect them.
Bacteria feed themselves in a variety of ways. Some eat other organisms. Some absorb dead organic material, such as decomposing flesh. Some parasitic bacteria kill their host. Some make their own food out of sunlight, carbon dioxide and water. In fact, these helped create the oxygen atmosphere of the earth. Some use water, and chemicals such as ammonia, sulphur, phosphorus, nitrogen, zinc, iron to produce their food. We call them nitrogen fixers. They are common in plant roots.
Aerobic bacteria grow only in the presence of oxygen. They can cause corrosion and bad smells. Anaerobic bacteria can only grow if there is no oxygen present. In humans, they are most commonly found in the gastrointestinal tract. They cause gangrene, tetanus, botulism and dental infections. Some grow with or without oxygen and are found in soil, water, vegetation, humans and animals. One example is salmonella. Human bacterial infections are mainly caused by mesophilic bacteria (like ecoli) - because our bodies are moderate (37 Celsius). Mesophiles thrive in moderate temperatures. The human intestine contains many beneficial mesophilic bacteria, such as dietary Lactobacillus acidophilus as well. Extremophiles thrive in conditions considered too extreme for most life forms - temperatures from 85 to 113 degrees Celsius, salt lakes, acidic or alkaline environments.
They multiply by dividing themselves, or by passing genes from one cell to another when they come in contact through a tube called pilus. Some bacteria move by gliding on surfaces. Others control their movement through internal gas bubbles. Some bacteria have tails and they rotate them like propellers going as fast as 0.00017 km per hour - the equivalent of a man running at 100 meters per second. E.coli can travel 25 times their own length in 1 second, equivalent to a horse running 215 km per hour.
When bacteria do not have enough resources to live they turn inactive. Spores can remain dormant for centuries. They are resistant to radiation, desiccation, starvation, chemicals and extremes of temperature. In 2007, biologists revived a 8-million-year-old bacterium from the Antarctic ice.
Most people react negatively to bacteria. But they create the air we breathe; the nitrogen in the soil that plants need. Friendly bacteria help the human body survive. Bacteria in the digestive system are crucial for the breakdown of nutrients, such as complex sugars, into forms the body can use. Friendly bacteria protect us from dangerous ones by occupying places in the body that disease causing bacteria want to occupy. Some friendly bacteria rescue us by attacking bad bacteria. Lactic acid bacteria have been used for the preparation of foods as cheese, soy sauce, vinegar, yoghurt and pickles and fermented foods for thousands of years. Bacteria can break down organic compounds at remarkable speed and help in waste processing. They are frequently used for cleaning up oil spills and clearing up toxic waste. Pharmaceutical and chemical industries use bacteria in the production of chemicals. Bacteria, such as Bacillus thuringiensis, can be used in agriculture instead of pesticides without the undesirable consequences of pesticides.
On the other hand some of the most deadly epidemics in human history have been caused by bacteria – Cholera, Diphtheria, Dysentery, Plague, Pneumonia, Tuberculosis, Typhoid, Typhus.
Here are some more odd facts:
1,458 new species of bacteria live in the bellybutton of human beings. Everyone’s bellybutton ecology is unique and one volunteer’s belly button harboured bacteria that had previously been found only in soil from Japan, where he had never been.
Bacteria only multiply – unlike humans - to the extent that there is food. The amount of bacteria on a pair of jeans reaches a maximum after 2 weeks of wear. You can wear them for the rest of your life without worrying about them getting any dirtier!
Human faeces is mostly bacteria that are both dead and alive.
Magnetospirillium magneticum has the ability to take in iron, convert it to magnetic magnetite, align it along its body, and travel using magnetic fields.
Millions of people don’t actually need to use deodorant (especially East Asians) because they have a gene that stops them from producing sweat that attracts body-odour-causing bacteria.
One teaspoon of the bacterium C. botulinum, properly distributed, could kill every human being in Asia.
The “smell” of rain on the earth is produced by bacteria.
Floating bacteria are effective at spurring condensation, leading to snow and rain. Some scientists propose spraying bacteria into the clouds to end droughts.
Deinococcus radiodurans can survive 10,000 times the dose of radiation lethal to humans, making it a prime candidate for the clean-up of nuclear waste.
Ralstonia metallidurans can turn dissolved gold into solid nuggets.
Some marine animals have specialized light organs which contain bioluminescent bacteria which turn on and off like a flashlight. The flashlight fish uses its light to communicate with other fish, attract prey and avoid predators. The bacteria benefit by receiving nutrients and oxygen from the fish's blood.
Bacteria signal to each other through chemicals produced. Through these signals, bacterial species know how many others of their kind exist and whether there is a “ quorum”. The bacteria change and coordinate their behaviour when a "quorum" is present.
Are humans beings the dominant life forms of the Earth, or are bacteria? The terrifying "thought control" talent of the Toxoplasma gondii protozoa is amazing. It infects rats and then alters their brains so that the rodents seek out their natural predator, cats. This is because T. gondii can only complete its reproductive cycle in feline intestines. The rats offer themselves to be eaten and the T. gondii parasites complete their lives. It also infects humans and I wonder how much of our activities come from its orders. After all, your body has 10 times more bacterial cells than human cells.
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