17 September: Bacteria

On this date in 1683 Dutch scientist Antony van Leeuwenhoek became the first to report the existence of bacteria. He spotted them using the microscope he'd just designed. Even though he published his observations to the Royal Society of London, nobody looked at bacteria again for over 100 years. Here are ten things you might not know about bacteria.

1. There are a lot of them - about about 5 million trillion trillion of them, outnumbering all other life on Earth. If you placed them all end to end, you'd get a line of bacteria reaching to the edge of the known universe. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh Water.
2. They're not all bad. Less than 1% of them cause illness. Many are beneficial to us, and even essential; but when they're bad, they're very, very bad. One teaspoon of the bacterium C. botulinum, if properly distributed, could kill every single human being in the USA.
3. Human beings are 90% bacteria - there are ten times more bacterial cells in the human body than human ones. In 2012, scientists discovered 1,458 new species living in in the human belly button alone. The make up of the bacteria living in a person's belly button is as individual as a fingerprint. It's even possible for a person to have bacteria in their belly button usually only found in places they've never visited. There are more bacteria in one human intestine than there are people on Earth.
4. Bacteria are the oldest life forms on the planet, having been here for at least 3.5 million years.
5. The word "bacteria" derives from the Greek word for a staff or cane, as the first bacteria to be discovered were rod shaped. Since then, other types have been found. Some, like E. Coli, have tails and can travel 25 times their own length in a second, equivalent to a Horse running 135 miles per hour.
6. They are literally everywhere. In 2007, biologists revived an 8-million-year-old bacterium extracted from the Antarctic ice. They have been found two miles underground, living off radioactive rocks. There are types which can survive almost 10,000 times the dose of radiation lethal to humans, so scientists are looking at using them to clean up nuclear waste. One of these species has been nicknamed “Conan the Bacterium.” A more sobering thought is that is we destroy ourselves in a nuclear war, the bacteria will still be there. Some scientists have gone so far as to transcribe the song, “It’s a Small World After All” into the DNA of a bacteria that is resistant to radioactivity, as a message to the life forms that will evolve from them. Bacteria are even found floating in the clouds, and scientists are discovering that seeding clouds with bacteria is a better way of making it rain than using chemicals or dust.
7. Other uses bacteria can be put to include making certain types of food, such as Yogurt, vinegar and even Chocolate and Coffee. Some can eat through rock and are useful in mining. They can also repair or create building materials and even turn dissolved Gold into solid nuggets. It's even thought bacteria can help cure diseases - scientists are discovering that the composition of bacteria in humans causes more diseases than previously thought, and altering the biodiversity of bacteria in the body could save lives.
8. There are a few species of bacteria which can be seen with the naked eye. Thiomargarita namibiensis can reach half a millimetre long and Epulopiscium fishelsoni 0.7 mm. At the other end of the scale are ultramicrobacteria which are as small as Viruses, although they have not been studied much. There could be some so small we haven't been able to discover them yet.
9. There are bacteria which glow in the dark. During the US Civil War some soldiers had wounds which glowed in the dark because they were infected with such bacteria. That was actually a good thing, as the glow in the dark bacteria killed other, more harmful ones so soldiers with glowing wounds were more likely to survive.
10. When things get tough, even for bacteria, they can re-write their own DNA, hoping for a beneficial mutation to help them survive.