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This bacteria can withstand 1,000x as much radiation as would kill a human
Meet Deinococcus radioduranst, the world's toughest bacteria.
- The bacteria is so resilient that it's been found on the walls of nuclear reactors.
- It's unique properties have fascinated scientists, who have proposed all kinds of applications for the bacteria that range from the practical to the whimsical.
- How does this supertough bacteria withstand radiation that would kill anything else, though?
What's the toughest thing on the planet? Cockroaches are famously difficult to eradicate, and it's said they're one of the few critters capable of surviving a nuclear apocalypse. The tardigrade can survive extreme temperatures, extreme pressures, and even the vacuum of space. Now there's another contender for the toughest living thing around: Deinococcus radiodurans.
In the Guinness World Book of Records, D. radiodurans is listed as "the world's toughest bacterium." It's classified as an extremophile, a living thing capable of surviving and thriving in conditions too hot, cold, or chemically antagonistic for the majority of life on Earth. Its toughness is so renowned, it's even been called "Conan the Bacterium."
What makes D. radiodurans so tough?
A tetrad of D. radiodurans observed via a transmission electron micrograph.
Credit: TEM of D. radiodurans acquired in the laboratory of Michael Daly, Uniformed Services University, Bethesda, MD, USA. http://www.usuhs.mil/pat/deinococcus/index_20.htm [Public domain]
The bacterium was discovered in 1956 by researcher Arthur Anderson, who was conducting experiments to see whether canned foods could be sterilized by blasting it with gamma radiation. However, a can of ground beef and pork spoiled despite Anderson's gamma radiation treatment. When he isolated the bacteria present in the beef and pork, he found D. radiodurans, happily munching away at the canned food.
This is where D. radiodurans got its name; the bacterium is uniquely resistant to radioactivity. Where 1,000 rads would kill a human within a couple of weeks, D. radiodurans can survived 1 million rads without breaking a sweat. At 3 million rads, significant numbers of the bacteria die, but a few still manage to survive. It's even been found on the walls of nuclear reactors.
But D. radiodurans isn't exactly shielded from radiation. When the small particles emitted by radioactive material shoot through living things, they tear up the DNA and proteins that life uses to function, ultimately destroying cells or causing them to mutate in unusual and unhealthy ways. D. radiodurans, like all life, is susceptible to this. But it excels at repairing the damage. All life can repair damage to their DNA to some extent, but D. radiodurans is so gifted at this process that it can take a dose of radiation that would kill your, or me, in literal seconds and be as healthy a bacterium as ever a day later.
D. radiodurans's trick to this remarkable durability is to have multiple copies of its chromosome and DNA repair molecules, enabling it to quickly take a similar strand of DNA and write it over the damaged kind. Each D. radiodurans cell contains between four and ten copies of its chromosomes. What's more, its chromosomes are bunched up in the shape of a donut, with each copy stacked on top of each other. Most bacterial life has its genetic material distributed much more loosely. Researchers speculate that D. radiodurans's tightly packed genetic material make it easier to find damaged DNA and correspondingly healthy DNA with which to repair the damage.
What can it be used for?
Obviously, a bacterium this unique offers some exciting opportunities to humanity. First, it could be used for bioremediation, or the process of using microorganisms to clean up contaminated environments. In areas with high radioactivity, D. radiodurans can be and has been genetically modified to consume and digest heavy metals or other toxic materials. It's incredible ability to repair its DNA is of interest to researchers looking into slowing down the human aging process — which is really just accumulated DNA damage — or improving our resistance to radiation and cancer.
More whimsically, D. radiodurans could be used as a means of storing information to retrieve later after a nuclear apocalypse. DNA is really just data in a biological format, and using this principle, researchers were able to translate the lyrics to It's a Small World into DNA segments and insert this message into D. radiodurans's DNA. After the bacteria reproduced 100 times, they could retrieve the song's lyrics from D. radiodurans's DNA with no errors whatsoever.
Maybe after all the bombs go off and we're all hiding in our basements from the irradiated, massive, and mutated insects that roam the nuclear wasteland, we'll be able to read D. radiodurans's DNA in search of a friendly message from the past.
- The weird properties of the world's toughest bacteria - Big Think ›
- The superbug crisis: Politics, profit, and Big Pharma - Big Think ›
Scientists used CT scanning and 3D-printing technology to re-create the voice of Nesyamun, an ancient Egyptian priest.
- Scientists printed a 3D replica of the vocal tract of Nesyamun, an Egyptian priest whose mummified corpse has been on display in the UK for two centuries.
- With the help of an electronic device, the reproduced voice is able to "speak" a vowel noise.
- The team behind the "Voices of the Past" project suggest reproducing ancient voices could make museum experiences more dynamic.
Howard et al.<p style="margin-left: 20px;">"While this approach has wide implications for heritage management/museum display, its relevance conforms exactly to the ancient Egyptians' fundamental belief that 'to speak the name of the dead is to make them live again'," they wrote in a <a href="https://www.nature.com/articles/s41598-019-56316-y#Fig3" target="_blank">paper</a> published in Nature Scientific Reports. "Given Nesyamun's stated desire to have his voice heard in the afterlife in order to live forever, the fulfilment of his beliefs through the synthesis of his vocal function allows us to make direct contact with ancient Egypt by listening to a sound from a vocal tract that has not been heard for over 3000 years, preserved through mummification and now restored through this new technique."</p>
Connecting modern people with history<p>It's not the first time scientists have "re-created" an ancient human's voice. In 2016, for example, Italian researchers used software to <a href="https://www.smithsonianmag.com/smart-news/hear-recreated-voice-otzi-iceman-180960570/" target="_blank">reconstruct the voice of Ötzi,</a> an iceman who was discovered in 1991 and is thought to have died more than 5,000 years ago. But the "Voices of the Past" project is different, the researchers note, because Nesyamun's mummified corpse is especially well preserved.</p><p style="margin-left: 20px;">"It was particularly suited, given its age and preservation [of its soft tissues], which is unusual," Howard told <em><a href="https://www.livescience.com/amp/ancient-egypt-mummy-voice-reconstructed.html" target="_blank">Live Science</a>.</em></p><p>As to whether Nesyamun's reconstructed voice will ever be able to speak complete sentences, Howard told <em><a href="https://abcnews.go.com/Weird/wireStory/ancient-voice-scientists-recreate-sound-egyptian-mummy-68482015" target="_blank">The Associated Press</a>, </em>that it's "something that is being worked on, so it will be possible one day."</p><p>John Schofield, an archaeologist at the University of York, said that reproducing voices from history can make museum experiences "more multidimensional."</p><p style="margin-left: 20px;">"There is nothing more personal than someone's voice," he told <em>The Associated Press.</em> "So we think that hearing a voice from so long ago will be an unforgettable experience, making heritage places like Karnak, Nesyamun's temple, come alive."</p>
Inequality in wealth, gender, and race grew to unprecedented levels across the world, according to OxFam report.
- A new report by global poverty nonprofit OxFam finds inequality has increased in every country in the world.
- The alarming trend is made worse by the coronavirus pandemic, which strained most systems and governments.
- The gap in wealth, race and gender treatment will increase until governments step in with changes.
People wait in line to receive food at a food bank on April 28, 2020 in Brooklyn.
Photo by Spencer Platt/Getty Images
Credit: Oxfam International
A supernova exploded near Earth about 2.5 million years ago, possibly causing an extinction event.
- Researchers from the University of Munich find evidence of a supernova near Earth.
- A star exploded close to our planet about 2.5 million years ago.
- The scientists deduced this by finding unusual concentrations of isotopes, created by a supernova.
This Manganese crust started to form about 20 million years ago. Growing layer by layer, it resulted in minerals precipitated out of seawater. The presence of elevated concentrations of 60 Fe and 56 Mn in layers from 2.5 million years ago hints at a nearby supernova explosion around that time.
Credit: Dominik Koll/ TUM