Thanks to Nature’s Fynd for sponsoring this episode.

We teamed up with Nature’s Fynd to explain the science behind Fy, their nutritional fungi protein. Check out the link in the description to learn more. [♪ INTRO].

Scientists have known for some time that certain animals breathe using their butts -- in some form or another. But in nature, it’s mostly limited to things like fish adapted to low-oxygen conditions. Now, researchers based in Japan and the US have determined that certain mammals -- like pigs, rats and mice -- can do this too.

Yep, that’s right. Mammals can breathe out of their butts. Technically, out of their intestines.

But if you thought we weren’t going to make as many butt jokes as possible…. I don't know what show you've been watching. In their paper published last week in the journal Med, not only do these researchers outline how this is possible, using a sort of oxygen enema they proposed a new way of treating respiratory failure in humans.

And it could potentially save your butt one day especially in places where conventional methods, like ventilators, are in short supply. Now before you click away in disgust, hear me out. Underwater creatures like sea cucumbers and some fish have all evolved the ability to breathe through their intestines if the need arises.

This skill comes in handy during times of distress, like when there are low levels of oxygen in the water. We mammals do not need to breathe in deoxygenated ponds, but mammalian intestines are pretty great at absorbing things like pharmaceuticals and nutrients. There are lots of blood vessels in that region covered with a thin mucus lining.

So in the new study, researchers suspected oxygen absorption in that region might be possible, even in animals not specially adapted to survive in low oxygen conditions. To find out for sure, they took several mice and scrubbed the intestines of some of them, to try to thin out the mucus layer. Sounds very unpleasant.

The mice were then subjected to dangerously low oxygen levels while having pure, compressed oxygen gas injected into their intestines. [pained grunt] 75 percent of the mice with the scrubbed intestines survived the almost hour-long experiment. Those without intestinal scrubbing survived for only a few minutes. But intestinal scrubbing isn’t what you’d call clinically feasible.

Maybe for the best. So the researchers replaced the oxygen gas with an inert, oxygenated liquid known as perfluorodecalin. This type of liquid is able to carry large amounts of oxygen, and is already in use in some human medicine.

It’s sometimes used as a substitute for blood during surgeries! The researchers exposed mice and pigs to life-threateningly low oxygen conditions, and flushed some of their intestines with this liquid, while the control group only received a saline solution. While the control group’s oxygen levels crashed, those that received the oxygen enema?

They stabilized. The researchers say their findings not only demonstrate that mammals are capable of absorbing oxygen through their intestines, but also that this new method may be a safe treatment for humans in respiratory distress. And, like, ideally, after so many mice and pigs have, like, you know, been through it.

It would need to go through additional safety testing and clinical trials, but the researchers believe it could be used in situations where ventilators aren’t readily available. There have already been severe ventilator shortages world-wide due to the COVID-19 pandemic. If approved for human use, this treatment could be a life-saving tool for patients in respiratory distress.

Now speaking of gas… in other news, researchers in Washington state have developed a new method for turning waste plastics into something useful -- jet fuel! And it only takes one hour from start to finish. Plastic recycling is complicated.

We have the best intentions when we toss a bottle in that bin, but it’s expensive, and takes a lot of time, heat, and energy to recycle. And it alters the plastic in such a way that it needs to be mixed with new plastic in order to create a similar product. And that’s not even going into the different kinds of plastic.

As a result, only nine percent of the plastic produced in the United States is recycled every year. Yikes. But new research, published this week in the journal Chem Catalysis, proposes an additional avenue for plastic recycling.

The researchers focused on polyethylene, the most commonly used type of plastic, found in everything from plastic bags to shampoo bottles to plastic furniture. They were looking for new ways to break that plastic down, to create more options for how to reuse it. Because if you could turn that plastic into more than just plastic, it might open up some new end points for that milk jug in your fridge.

But chemically breaking down plastic can also be a challenge, in that it can require a catalyst, which is a substance that increases the rate of a chemical reaction, plus high temperatures, ranging from 300 to 900 degrees Celsius. But this new procedure uses a catalyst that’s a combination of ruthenium metal and carbon, which turns out to be particularly effective at breaking the bonds within the plastic. The reaction also doesn’t require as much heat compared to other methods - it works at 220 degrees Celsius.

Plus, it’s fairly speedy. Once the researchers had perfected their method, around 90 percent of the plastic was broken down in just an hour. The researchers were able to adjust the processing conditions, such as temperature, time and amount of catalyst, in order to fine-tune what type of products were produced at the end, including higher-dollar items like jet fuel.

They believe that this same process will work on other types of plastic as well. We can safely assume that the gases leftover after the jet fuel burns are still going to end up in the atmosphere. But the plastic won’t end up in a landfill this way, and you can definitely argue that giving that carbon a second go-round after pulling it out of the ground is still a greener approach.

It’s not a perfect solution to our plastics problem, but it might be a piece of the puzzle. Thanks for watching this episode of SciShow, which was brought to you by Nature’s Fynd, the fungi-based food company for optimists. Nature’s Fynd makes delicious vegan foods that all started with a microbe with origins in Yellowstone National Park.

From a NASA-backed research project, through their novel fermentation technology, foods made with Fy, their nutritional fungi protein, are making their way to your table. And I mean it when I say the food tastes great! I got to have their fungi-based cream cheese, which, I was like, "Ok, I'll eat fungi-based cream cheese..." But then...

I need it! I need more! If you want to learn more about Nature’s Fynd and the science behind their meatless and dairy-free foods, click on the link in the description. [♪ OUTRO].