ARI SHAPIRO, HOST:
It's time for our science news roundup from Short Wave, NPR's science podcast. I am joined by Emily Kwong and Jessica Yung - good to have you both back here.
EMILY KWONG, BYLINE: Hi, Ari.
JESSICA YUNG, BYLINE: Hey. How are you doing?
SHAPIRO: I'm great. So, as usual, you've brought us three science stories that caught your attention this week. What are they this week?
YUNG: The secret behind the world's most radiation-resistant microorganism.
KWONG: Cures for our loneliness epidemic.
YUNG: And why some animals can restore their hearing naturally, even though other animals, like us, cannot.
SHAPIRO: I'm intrigued that there is a radiation-resistant microorganism, this, like...
KWONG: Oh, just you wait.
SHAPIRO: ...Super-tiny little thing. What is it?
YUNG: Oh, totally. OK, so formally, this bacteria is called Deinococcus radiodurans. It was discovered back in the 1950s and 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.
KWONG: Which is why scientists have given it this funny nickname - Conan the bacterium, a resilient superhero of the microbial world.
SHAPIRO: Do kids today even know what "Conan The Barbarian" is? I feel like that's such a dated reference.
KWONG: True. Email us, kids. Let us know.
SHAPIRO: OK. I'm assuming scientists have just been dying to find out the secret to this Conan the bacterium's radiation resistance ever since.
YUNG: 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.
MICHAEL DALY: The big question has been, how are these things coming together? The magic of how these things come together has been a mystery.
KWONG: This is Michael Daly, a professor of pathology at the Uniformed Services University who has studied the Conan bacteria for decades.
SHAPIRO: Please tell me he has solved the mystery.
YUNG: 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...
BRIAN HOFFMAN: I never confessed to Mike at the time. I absolutely believed that the efficacy was just the sum of the pieces.
YUNG: Meaning they would just see as much radiation resistance as there was for each of those parts individually. But it turns out...
HOFFMAN: Oh, my God, it is more than the sum of its parts. It's - there's something new that forms when you put the pieces togethe. Which makes it better than one or the other is that the combination they interact with each other.
SHAPIRO: The whole is greater than the sum of its parts - amazing - like, a scientific actual application of that metaphorical artistic idea.
KWONG: (Laughter) Yeah. Look. When combined, these three - phosphate, manganese and peptides, when combined, 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.
DALY: 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.
YUNG: Michael says that he hopes that this can lead to innovations, for example, of medication that astronauts can take to make them more radiation-resistant before, you know, long missions to Mars.
SHAPIRO: 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 U.S. of all ages. We've been hearing about it for years. What's new?
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.
YUNG: 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.
SHAPIRO: That's still a lot of people (laughter).
KWONG: Yeah.
YUNG: Yeah.
KWONG: One third of...
SHAPIRO: Yeah.
KWONG: ...Older adults - it's a lot. And an outside researcher thinks this could be an undercount. Geriatrician Thomas Cudjoe 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.
THOMAS CUDJOE: We all may experience loneliness at points in our lives, but I think it's the longer experience of it or persistence that really leads to some of the negative health outcomes that we talk about in terms of increasing risk for cardiovascular disease, in terms of increasing the risk for dementia.
YUNG: And to that point, a 2022 study found that being chronically lonely can make people three times more likely to develop dementia.
SHAPIRO: So what do the researchers recommend on how to bring those loneliness numbers down?
KWONG: Yeah. Lead author Preeti 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.
PREETI MALANI: We can all walk across the street. We can knock on people's doors. We can make plans to visit.
YUNG: 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.
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.
SHAPIRO: 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.
YUNG: Yeah.
SHAPIRO: How do they do that?
YUNG: It's cool - 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.
SHAPIRO: That's why I wear ear plugs when I go to loud concerts.
KWONG: Smart.
YUNG: But if you were a zebrafish, you wouldn't have to because you could regenerate those cells.
KWONG: (Laughter).
SHAPIRO: Because I wouldn't have ears.
KWONG: They do have ears. That's the thing.
SHAPIRO: Wait. Zebrafish have ears?
KWONG: They have inner ears. Go on, Jess.
YUNG: Well, basically, some fish and lizards have supporting cells that can act almost like understudies. If the main hair cells die onstage, for example, the supporting cells are right there to just bring hearing back.
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.
SHAPIRO: So why do these ear understudies work in some fish and lizards but not mammals?
YUNG: 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.
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.
SHAPIRO: So what does this mean for humans?
YUNG: It means more research. The study's lead author, Tuo Shi, says they want to understand why enhancers close for some species and not others. He's a Ph.D. student at the University of Southern California, and he says that if the enhancers can be reopened, then maybe...
TUO SHI: We 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 hair cells.
YUNG: And if that works in mice, then there's the hope that one day maybe scientists will be able to reverse deafness in humans, too.
SHAPIRO: That's Jessica Yung and Emily Kwong from NPR's science podcast Short Wave. You can subscribe for new discoveries, everyday mysteries and the science behind the headlines. Thank you both.
KWONG: Thank you so much, Ari.
YUNG: Thank you.
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