Conan The Bacterium's Superpower: Resisting Radiation

In the 1950s, scientists exposed a tin of meat to a dose of radiation that they expected would kill all forms of life. But one organism defied the odds and lived: Conan The Bacterium. Turns out this microorganism, known to science as Deinococcus radiodurans, is capable of surviving extreme levels of radiation — thousands of times the amount that would kill a human. So what's Conan's secret? Want more stories about the microbial world? Let us know by emailing us at [email protected] mailto:[email protected]! See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:00Speaker 00

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• 0:15Speaker 00

  You're listening to Short Wave from NPR.

• 0:19Speaker 01

  Hey, Short Wavers. Jessica Young here.

• 0:21Emily Kwong?

  And Emily Kwong.

• 0:22Speaker 01

  With our biweekly science news roundup, featuring the hosts of All Things Considered. And today, we have Ari Shapiro.

• 0:29Speaker 03

  Hello. Happy to be here. I hear today we're talking about the secret behind the world's most radiation-resistant microorganism.

• 0:38Emily Kwong?

  We also have cures for our loneliness epidemic.

• 0:41Speaker 01

  Plus, why some animals can restore their hearing naturally, even though other animals, like us, cannot.

• 0:47Emily Kwong?

  All that on this episode of Short Wave, the science podcast from NPR.

• 1:04Speaker 04

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• 2:20Speaker 01

  Okay, Ari, where do you want to start?

• 2:22Speaker 03

  I'm intrigued that there is a radiation-resistant microorganism, this like, super, super tiny little thing. What is it?

• 2:30Speaker 01

  Oh, totally. Okay, so formerly, this bacteria is called Dinococcus reudurans. It was discovered back in the 1950s. It has been long known to withstand radiation doses thousands of times higher than what it would take to kill a human or any other living thing.

• 2:44Emily Kwong?

  Which is why scientists have given it this funny nickname, Conan the bacterium, a resilient superhero of the microbial world.

• 2:51Speaker 03

  Do kids today even know what Conan the Barbarian is? I feel like that's such a dated reference.

• 2:55Emily Kwong?

  True. Email us, kids. Let us know.

• 2:58Speaker 03

  I'm assuming scientists have just been dying to find out the secret to this Conan the bacterium's radiation resistance ever since.

• 3:04Speaker 01

  Yeah, definitely, because the implications could be really huge, like, helping protect astronauts from radiation in space or other kinds of like, medical applications. But over the years, scientists have suspected that the bacteria's radiation shield has probably something to do with these ingredients inside of its cells, like phosphate, manganese, and peptides.

• 3:25Speaker 05

  The big question has been, how are these things coming together? The magic of how these things come together has been a mystery.

• 3:33Emily Kwong?

  This is Michael Daly, a professor of pathology at the Uniformed Services University, who has studied the Conan bacteria for decades.

• 3:41Speaker 03

  Please tell me he has solved the mystery.

• 3:43Speaker 01

  Well, with the help of Brian Hoffman, yes. Brian's a chemist from Northwestern University, and conveniently, he has access to a tool that allows you to see what's happening inside a living cell and study its chemistry. So he and Michael partnered up, and Brian says going into the research...

• 3:58Speaker 06

  I never confessed to Mike at the time. I absolutely believed that the efficacy was just the sum of the pieces.

• 4:08Speaker 01

  Meaning, they would just see as much radiation resistance as there was for each of those parts individually. But it turns out...

• 4:15Speaker 06

  Oh, my god. It is more than the sum of its parts. It's something new that forms when you put the pieces together, which makes it better than one or the other, is that the combination, they interact with each other.

• 4:28Speaker 03

  The whole is greater than the sum of its parts. Amazing. Like, a scientific, actual application of that metaphorical, artistic idea.

• 4:36Emily Kwong?

  Yeah, look, when combined, these three phosphate, manganese, and peptides offer astounding radiation protection. The details about this appear in the proceedings of the National Academy of Sciences. And Michael says this breakthrough means big things for the future.

• 4:50Speaker 05

  We now have a much better understanding of the nature of the complex and how it is formed, which means we can now try and think of ways of making them better.

• 5:02Speaker 01

  Michael says that he hopes that this can lead to innovations. For example, a medication that astronauts can take to make them more radiation resistant before, you know, long missions to Mars.

• 5:12Speaker 03

  Cool. All right, let's move on to the second topic, how to help with the loneliness crisis, which we know affects millions of people in the US of all ages. We've been hearing about it for years. What's new?

• 5:23Emily Kwong?

  Yes, we have a very lonely society. And there are a lot of studies out there showing this, including the National Poll on Healthy Aging from the University of Michigan. Now, for six years, the poll gathered household data from older Americans ages 50 to 80 about how lonely they are, loneliness being defined as feeling a lack of companionship.

• 5:41Speaker 01

  Yeah, and after a spike in loneliness in the first few years of the COVID pandemic, the poll found that this year it's back down to pre-pandemic levels. That 33% of older adults feel lonely at least some of the time.

• 5:54Speaker 03

  That's still a lot of people.

• 5:56Emily Kwong?

  Yeah, one third of older adults. It's a lot. And an outside researcher thinks this could be an undercount. Geriatrician Thomas Cujo at Johns Hopkins University is especially worried about older adults who are, say, homebound or cognitively impaired and may not like take part in a poll like this.

• 6:13Speaker 07

  We all may experience loneliness at points in our lives. But I think it's the longer experience of it, our persistence, that really leads to some to know that negative health outcomes that we talk about in terms of increasing risk for cardiovascular disease, in terms of increasing the risk for dementia.

• 6:29Speaker 01

  And to that point, a 2022 study found that being chronically lonely can make people three times more likely to develop dementia.

• 6:35Speaker 03

  So what do the researchers recommend on how to bring those loneliness numbers down?

• 6:41Emily Kwong?

  Yeah, lead author Preteu Malani wants everyone to think of loneliness as a health problem like cancer or heart disease as something that can be treated and prevented. We can actively cultivate human connection.

• 6:53Speaker 01

  We can all walk across the street. We can knock on people's doors. We can make plans to visit. Or find community, join book clubs, faith groups. The NPR Shots blog recently profiled nonprofits that pair older adults with teens to address the loneliness crisis.

• 7:08Emily Kwong?

  And there's medical interventions, too, like getting fitted for hearing aids so those who are hard of hearing can connect like we are now through good old fashioned conversation.

• 7:16Speaker 03

  Oh, interesting, a medical solution to this social problem. Well, speaking of hearing, let's go to the final story, how some animals can restore their hearing. How do they do that?

• 7:26Emily Kwong?

  It's cool.

• 7:27Speaker 01

  By regenerating hair cells in their inner ears. I mean, humans have these hair cells, too, but when they're damaged, they don't come back.

• 7:35Speaker 03

  That's why I wear earplugs when I go to loud concerts.

• 7:37Emily Kwong?

  Smart.

• 7:38Speaker 01

  But if you were a zebrafish, you wouldn't have to because you could regenerate-

• 7:41Speaker 03

  Because I wouldn't have ears.

• 7:43Emily Kwong?

  They do have ears.

• 7:44Speaker 03

  Wait, zebrafish have ears?

• 7:45Emily Kwong?

  They have inner ears. Go on, Jess.

• 7:48Speaker 01

  Well, basically, some fish and lizards have supporting cells that can act almost like understudies. If the main hair cells die on stage, for example, the supporting cells are right there to just bring hearing back.

• 7:59Emily Kwong?

  But what's weird is that we humans have supporting cells in our inner ears, too. They just fail to step into the spotlight and take over. And that's true of all adult mammals, like mice.

• 8:09Speaker 03

  So why do these ear understudies work in some fish and lizards but not mammals?

• 8:14Speaker 01

  Well, according to an analysis published in the Proceedings of the National Academy of Sciences this week, it might have something to do with gene enhancers.

• 8:21Emily Kwong?

  Think of gene enhancers like a switch. They can be open or closed. And in adult mammals, which can't regenerate hearing, the enhancers are closed. But according to this new research, these switches are on for adult zebrafish, meaning the curtain can be raised for the supporting cells to step forward and do their thing and restore the hearing. The scientists also found that if you took them out, the zebrafish lose this ability to regenerate hair cells.

• 8:42Speaker 03

  So what does this mean for humans?

• 8:43Speaker 01

  It means more research. The study's lead author, Tuosu, says they want to understand why enhancers close for some species and not others. He's a PhD student at the University of Southern California. And he says that if the enhancers can be reopened, then maybe- You can use some sort of gene therapy approach to put that gene back into the mouse-supporting cells. To be there and see if that would allow mouse to regenerate her cells. And if it works in mice, there's the hope that one day, maybe scientists will be able to reverse deafness in humans, too.

• 9:15Emily Kwong?

  That'd be cool.

• 9:15Speaker 01

  Yeah, I know, right? Ari, thank you so much for being on the show today.

• 9:19Speaker 03

  Oh, it's a pleasure. I don't have to tell you guys. Science is cool.

• 9:21Speaker 01

  Definitely.

• 9:22Emily Kwong?

  It is. It's cool. It's always happening, so we'll be back.

• 9:25Speaker 03

  Science is always happening. True statement.

• 9:34Emily Kwong?

  You can hear more of Ari on Consider This, NPR's afternoon podcast about what the news means for you.

• 9:42Speaker 01

  This episode was produced by Rebecca Ramirez and Jordan Marie Smith. It was edited by Rebecca Ramirez and Christopher Intagliato.

• 9:50Emily Kwong?

  Tyler Jones, check the facts. Ted Mebane and Gilli Moon were the audio engineers. Shout out. And I'm Emily Kwong.

• 9:55Speaker 01

  And I'm Jessica Young. Thanks for listening to Short Wave, the science podcast from NPR.

• 10:19Speaker 00

  Stay tuned for the following announcements and messages from our sponsors.