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Join Hank Green to learn ten weird, scary, and amazing things fungi can do!

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Magic Mushrooms

Ergot Poisoning

Zombie Ants:

Medicinal Fungi:

The largest fungus:

The fastest fungus:

The deadliest fungi:

Cheesy fungi:

Boozy fungi:

Hank: My friend the toadstool, he just left the party, 'cause there wasn’t mushroom! And it’s too bad, 'cause he was a real fun-guy.

OK... ahh... in addition to being fun guys, fungi are incredible organisms. They make up their own kingdom in the eukaryotic domain of the tree of life, separate from animals and plants. This kingdom includes everything from microscopic organisms like yeast and mold, to those familiar dome-shaped mushrooms you can find at the grocery store... or in Super Mario. And since there are so many different kinds of fungi, it’s no wonder that some of them have pretty crazy talents.


First, we have a classic fungus: the mushroom. The magic mushroom, to be precise. These mushrooms contain the chemical compounds psilocybin and psilocin. In the human body, the psilocybin gets broken down into psilocin, which is the active form of the hallucinogenic drug.

The chemical structure of psilocin is similar to the neurotransmitter serotonin, which normally sends signals between brain cells to regulate things like mood, memory, and sleep. So, psilocin tricks the brain into activating those serotonin receptors. And this can cause hallucinogenic effects, like changing thought patterns and mood, visual distortions, and even a sense of euphoria.

There’s some sketchy anthropological evidence that magic mushrooms could have been used in religious ceremonies by different cultures, but those theories are controversial among historians. The mushrooms hit the US cultural scene in the 1950s, though, after a mycologist, a scientist who studies mushrooms, brought the practice back after a trip to Mexico. By the 1970s, these mushrooms were illegal in the US, after being widely used as a recreational drug.

But they may be making a comeback for another purpose: psychotherapy. With permission from the U.S. government, certain researchers are carefully conducting studies to explore the benefits of small doses of psilocybin to treat conditions like post-traumatic stress disorder and chronic depression.

Some mind-altering fungi have more dangerous side effects. In fact, one of the most famously horrifying events in early American history may have a fungal infection to blame. Ergot fungi are members of the genus Claviceps. And the most well-known variety is Claviceps purpurea, which grows on rye and other grains. The fungus produces some toxic nitrogen-containing compounds called alkaloids. In particular, it creates lysergic acid. Which might sound familiar because it’s used to synthesize the psychedelic drug lysergic acid diethylamide, better known as LSD.

Lysergic acid alone can lead to mania and psychosis, while other alkaloids in ergot fungus can cause seizures and spasms, headaches, nausea, crawling skin, and vomiting. As it turns out, many of these fun symptoms are very similar to the effects of the so-called “bewitchment” recorded in the Salem Witch Trials in 1692, where both women and men were accused of witchcraft, tried in court, and even executed.

At the time, rye was a staple in the diets of Salem residents. And warm, humid weather the previous year would have made a prime breeding ground for ergot fungus. Ergot poisoning probably can’t account for all of the hysteria surrounding the witch trials, but it all could have started with some fungus in their food.

Pop culture is full of zombies, but it’s a relief to know that the apocalypse is not upon us... yet. The same can not be said for Camponotini ants, who face a unique threat to their colonies: zombie ants! A particular type of fungus called Ophiocordyceps unilateralis can take control of the ants it infects.

The infected ants show extremely specific behavior, they travel down to a lower level in the forest where the air is just humid and cool enough, and find a leaf on the north side of a plant about 25 centimeters above the ground. Then, they clamp down onto the underside of the leaf and die. After a few days in these ideal conditions, thin stalks of fungus sprout from the ant’s head so that spores can be released, in the hope of infecting more ants and continuing the cycle.

Scientists aren’t sure yet how this fungus can so carefully control the ant’s behavior, but this isn’t the only parasite to have evolved mind-controlling abilities. One of the great medical achievements of the 20th century was the discovery and isolation of the antibiotic penicillin. Without a reliable way to kill off the bacteria causing an infection, something a simple as a scratch could turn out deadly.

But, in the late 1920s, bacteriologist Alexander Fleming, noticed that Penicillium notatum mold had contaminated one of his petri dishes and killed all of the bacteria it touched. That was because the Penicillium mold produced a bacteria-killing chemical that Fleming eventually called penicillin. It attacks the enzymes that build the bacterial cell walls, so the walls fall apart, and the bacterium dies. Researchers at Oxford University then worked on mass-producing, purifying, and testing the antibiotic, which went on to save thousands of soldiers from death by infection in World War II. Pretty incredible stuff for a bread mold!

And, Penicillium isn’t the only life-saving fungus out there. Tolypocladium inflatum seems pretty boring at first glance. It lives in Norwegian soil and can infect beetle larvae. But this fungus produces a compound called cyclosporin, which is really good at suppressing our immune systems.

It sounds dangerous and bad when you put it that way, but cyclosporin is an important drug that keeps organ implants from being rejected. Normally, the patient’s immune system would see the implanted organ as an intruder and attack it using the body’s first line of defense: the T-cells. But cyclosporin inhibits those cells, preventing the attack, and protecting the new organ as the patient's body adjusts. And continued low doses of this drug can keep organ transplant recipients healthy for years.

When you think fungi, you usually think... like, pretty small. Like, cute-little-mushrooms-in-the-forest small. Or even microscopic-mold small. But it turns out that some fungi can get huge. In fact, the largest living organism on the planet is a massive honey fungus, of the Armillaria solidipes variety. This honey fungus has genetically identical cells that can communicate and coordinate with each other, which, by one biological definition, makes it a single organism.

It’s estimated to cover around 9.6 square kilometers in Oregon, and may be thousands of years old. But it’s not obvious how big this thing is. Clumps of mushrooms will appear above the surface of the soil to release spores, but most of the fungus exists underground. Root-like rhizomorphs search for new host trees to infect, while a network of thin, tube-like filaments called mycelia absorb nutrients from the soil to keep this fungus growing.

Not many people notice Pilobolus fungus, since it’s a couple centimeters tall and mostly grows on manure, but this unglamorous fungus has a secret superpower. During its reproductive phase, it forms thin, pale stalks, called sporangiophores, with bulbs at the end containing spores, called the sporangium. Pressure builds in the bulb until it eventually bursts, sending the spores shooting around two meters away into nearby grass, so cows can eat it and the circle of life can continue.

Now, that might not sound very impressive, but these spores are accelerated at around 20,000 gs. To put it in perspective, the shot coming out of a shotgun probably maxed out at around 15,000 gs. That is a lot of acceleration for a tiny fungus.

Death Cap and Destroying Angel mushrooms are easily mistaken for edible fungi. But, as you might’ve guessed from their names, they contain some of the most deadly substances known to humans. Other dangerous fungi include the deadly webcap and the fool’s webcap. Both webcaps are part of the Cortinarius genus and look like common brown mushrooms that you can eat. But, they produce a toxin called orellanine, which can cause kidney failure, and sometimes death. Plus, it can take anywhere from two days to three weeks for symptoms to show up, so poisoning can be really hard to diagnose.

The Japanese fungus Podostroma cornu-damae has some particularly nasty effects as well. Eating this rare red fungus causes altered perception, severe upset stomach, hair loss, peeling skin, and even shrinking of the cerebellum, the part of your brain responsible for movement and coordination. The fungus is so rare that not many cases of poisoning have been reported, but most of the known cases have been fatal. So it’s probably not a great idea to go around eating random wild mushrooms.

To make cheese, milk has to be soured, causing the solids, or, the curds, to separate from the liquids, or, the whey. The curds are then mixed with some other stuff, before they’re processed into the final cheese product. In the case of some popular cheeses like Roquefort, a type of blue cheese, this includes deliberately contaminating the curds with fungus!

Penicillium roqueforti is another bread mold, from the same Penicillium genus as the life-saving antibiotic. The mold produces enzymes that break down proteins in the cheese curds, helping create a distinctive smooth texture and strong, tangy taste.

Legend has it that people would place loaves of bread in the caves surrounding the Roquefort region of France, hence the name. The loaves would grow moldy and dry out, be pulverized into a powder, and then added to the cheese, giving it that delightful blue veiny appearance. Nowadays, Penicillium roqueforti can be purchased in stores, so you can make your own fungus-filled blue cheese at home!

Humans have been consuming alcoholic beverages for at least 7,000 years. And it turns out making beer wouldn’t be possible without the help of a fungal friend named yeast. Specifically, a yeast called Saccharomyces cerevisiae. See, in beer brewing, grains are cooked in water to form a mash. And then, they’re boiled to break all the starches down into simpler sugars, and flavoring agents like hops are added. Once this mixture cools down, the yeast is added, and that’s when the magic happens.

Yeast eat all those sugars in the mash to give them energy to reproduce, in a chemical process called fermentation. And they also generate a lot of waste, in this case, carbon dioxide and ethanol. The carbon dioxide is what gives the beer its characteristic fizz, while the ethanol is what gives humans their characteristic buzz.

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