Learn about how humans literally use their noses to navigate; why the blue blood of horseshoe crabs is essential for developing drugs like a COVID-19 vaccine; and the truth behind 5 myths about summer dangers.
Learn about how humans literally use their noses to navigate; why the blue blood of horseshoe crabs is essential for developing drugs like a COVID-19 vaccine; and the truth behind 5 myths about summer dangers.
Humans use their noses to navigate, and both nostrils are important by Grant Currin
Why the blue blood of horseshoe crabs is essential for drug development by Cameron Duke
5 Myths About Summer Dangers by Ashley Hamer
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/you-navigate-with-your-nose-busting-5-summer-myths-and-using-horseshoe-crabs-blue-blood-to-develop-new-medicine
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about how humans literally use their noses to navigate; why horseshoe crabs hold the secret ingredient for drug development; and the truth behind 5 myths about summer dangers.
CODY: Let’s satisfy some curiosity.
Your sense of smell is good for enjoying food and noticing gas leaks, but does it help you find your way around? New evidence suggests that it does! Or at least that it could.
You already know that having two eyes makes navigation a lot easier. For people with normal vision, the brain uses the slightly different images delivered by each eye to help create the three-dimensional world you see. A different region of the brain uses information from each ear to help determine what direction sound comes from. Pretty nifty, right? Well, according to this research, your brain might do something similar with your nostrils — meaning you might have an easier time navigating if you’ve got two of them. These findings were a big surprise, and they’re bound to have researchers paying closer attention to what the nose knows.
The study involved about 200 participants and a series of very subtle experiments, with a pretty unusual setup. The participants were asked to look at a screen and watch a series of very short videos of gray pixels moving on a black background. They look like you’re flying through a flurry of snowflakes. The different videos were animated to make it seem like the viewer was headed very slightly to the left or the right, but only slightly — I’ve seen them, it’s super hard to tell. The participants just had to decide whether they were headed left or headed right in each video.
They also wore a nosepiece that let the researchers pipe different amounts of fragrance into each nostril. For example, a participant might have had a medium amount of vanilla in the left nostril and a very faint amount in the right one. They were asked to inhale through the nose and exhale through the mouth.
After running the experiment several different ways and crunching the numbers, the researchers concluded that the different intensities of smell did, in fact, affect what direction the participants thought they were traveling. In the same way hearing a car more prominently in one ear tells you which direction it’s coming from, smelling a scent more prominently in one nostril than the other gives you a directional clue, too. And the greater the ratio from one nostril to the other, the greater the effect.
And get this: the effect was completely subconscious. The participants couldn’t reliably say which nostril was smelling the stronger odor. It turns out that your sense of smell affects you in ways you can’t even comprehend.
Researchers have made countless medical breakthroughs over the last several decades — with some help from a secret ingredient that you might not expect. It’s the most valuable medical resource in the world, and it fetches tens of thousands of dollars per gallon. Believe it or not, I’m talking about the blood of one weird species of crab: horseshoe crabs. They’re odd little creatures, and their story is fascinating… and a little alarming.
In case you’ve never seen one, horseshoe crabs look like flat, brown bicycle helmets with tails, and they’re actually closer to spiders than crabs. They’re also “living fossils” that haven’t changed much in about 450 million years, but that’s not the only thing that makes them special: their extremely valuable blood is blue. By “extremely valuable,” I mean that a gallon of it costs about $60,000. So it’s not surprising that there’s a whole industry devoted to capturing horseshoe crabs and draining their blood. This blood is so valuable because it is the only known natural source of a protein called limulus amebocyte lysate [LIME-yoo-luss uh-MEE-buh-site LYE-sate], or LAL. It comes from the crab’s immune cells, called amoebocytes, and researchers think it evolved as a way to fight bacterial infections in their blood. You can drop a tiny amount of horseshoe crab blood in a liquid solution contaminated with bacterial endotoxins — which are a telltale sign of potentially harmful bacteria — and it’ll immediately coagulate into a gel.
This isn’t just a neat party trick. LAL has become essential to the medical industry. Since the 1970s, it’s been used to test bacterial contamination in every vaccine and medical device that’s been developed. Kind of a big deal.
To get enough material for all the testing, 600,000 horseshoe crabs are harvested for their blood every year. Now, we only drain about 30 percent of their blood before releasing them — that’s about three times the portion you might donate during a blood drive. But due to the stress of being handled, 30 percent of the crabs don’t survive the ordeal. And that’s causing some population problems. In 1990, 1.24 million horseshoe crabs lived in the Delaware Bay, which is a common location for medical crab harvesting. By 2002, the population had fallen to 330,000 — that’s a drop of nearly 75 percent. This reliance on horseshoe crabs puts a strain on the environment because many species rely on horseshoe crab eggs for food.
Because of this, many medical researchers and environmental activists have pushed for the development and use of a synthetic alternative. One alternative has been developed and is in use in parts of the world outside the US, but the FDA has so far declined to approve its use. For now, crab blood is the best we’ve got.
If we run out of horseshoe crabs, we might have to go back to the way testing was done before, which was injecting thousands of rabbits with potentially contaminated vaccines to see if they get sick. So, yeah, let’s hope it doesn’t come to that. In the meantime, take a moment to appreciate these little unsung heroes of blood donation.
ASHLEY: Today’s episode is sponsored by KiwiCo. KiwiCo creates super cool hands-on projects designed to expose kids to concepts in STEAM — that's science, technology, engineering, art and design, and math. All from the comfort of home! Each line caters to different age groups, with a variety of topics to choose from. The crates are also all designed by experts and tested by kids, and teach a new STEAM concept.
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I love summer. But it does have its dangers. From mosquito bites to sunburns, being out in the warm weather can lead to some... “less than pleasant” experiences. But some of the biggest summer dangers you’ve heard about probably aren’t as risky as you think — and others are actually more dangerous. So today, I’m gonna debunk five summer myths to make enjoying the outdoors a little easier...and safer.
Myth #1: Mayonnaise Causes Food Poisoning
Actually, it’s the opposite. Mayonnaise contains vinegar or lemon juice, both of which are acids that actually help kill bacteria. So, go on, live a little, and add some mayonnaise to that potato salad you brought for the summer picnic. It’ll actually reduce the risk that other ingredients could make you sick.
Myth #2: You Can't Be Allergic to Bee Stings If You've Never Been Stung
Sorry, you can. But luckily, even if you have an allergic reaction to your first sting, it’s unlikely to be fatal. Even so, if you have signs of dizziness, tingling, or swelling of your lips and tongue after a bee sting, get to an emergency room right away.
Myth #3: Char Is the Best Part of Grilling
Char is the most cancerous part of grilling. The high temperatures involved with grilling create two potent carcinogens, so charred meat is not good for you. Luckily, you can reduce the risk in a very delicious way: marinating your meat in acids like lemon juice, vinegar, or wine.
Myth #4: The Higher Your Sunscreen's SPF, the Better
While a higher SPF, or sun protection factor, does block more UV radiation, it’s not as much as you think. SPF 15 blocks 93 percent of UV radiation while SPF 50 blocks just five percent more. In the end, it’s more about the amount of sunscreen on your body and how often you apply it.
Myth #5: Citronella Repels Mosquitos
This one is bad news all around. A 2017 study found that not only are mosquitoes not repelled by citronella candles, they might even like the smell, just like we do. Things that do work are DEET and an equally effective natural remedy, which is oil of lemon eucalyptus spray, known as PMD.
So, put on your sunscreen and lemon eucalyptus spray, grab your marinade, and have an awesome summer!
CODY: Let’s recap what we learned today to wrap up. Starting with
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CODY: Today’s stories were written by Ashley Hamer, Cameron Duke, and Grant Currin, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Scriptwriting was by Cody Gough and Sonja Hodgen. Curiosity Daily is produced and edited by Cody Gough.
CODY: Join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!