Fungus for Medicine
Mark – Gilchrist – Professor Richard Fortey – Beatrix Potter
This is Mark Gilchrist, a consultant pharmacist at St Mary’s Hospital, London. He spends much of his day administering and prescribing the most widely-used type of drug on the planet – antibiotics.
Mark Gilchrist “Antibiotics are tremendously important in our fight against infection. Up to about 30% of patients within a hospital setting can be on antibiotics at any one time and that’s used to treat things like pneumonias to simple skin and soft tissue infections and prevent surgical site infections post operatively.”
The invention of antibiotics has been a game changer for medicine and mankind. And we owe it all to fungi. In 1928, scientist Alexander Fleming was carrying out research at St Mary’s.
He was studying the staphylococcus bacterium, and left some samples on his desk, before heading off on holiday, expecting them to grow and develop while he was away. When Alexander Fleming returned from his holiday to resume his research on bacteria here in this lab, he noticed something extraordinary. His bacteria samples were dead. They had been completely destroyed by fungi. Intrigued by why this had happened, Alexander Fleming examines his samples further.
He realised that a fungus spore, possibly from a lab below, must have landed on the gel plate and germinated. The spore had rapidly started to feed on the contents of the dish, starving and ultimately killing the bacteria. The significance wasn’t lost on Alexander Fleming. This could be a new way to fight bacterial infection inside the human body.
His discovery led to the creation of the world’s first antibiotic – penicillin.
And it only happened thanks to some tiny spores from a fungus, carried on the breeze. But to understand how those spores came to be there at all, we need to delve deeper into the secret world of fungi, right back to the start of their life cycle, to the moment a new fungus begins.
I’ve come to Scotland to see something I’ve always wanted to see but never have, although I’ve rehearsed it many times in my mind’s eye.
This is one of the largest mushroom farms in the UK, and inside each of these polytunnels, there’s a spectacular natural phenomenon taking place – the birth of fungi. It’s a magical process, normally invisible, but tonight I’m going to see it clearly for the first time.
Well, to a mushroom person, of course, this is like being in heaven, and everywhere you look, it’s extraordinary – this laser torch picks out little white specks. They’re so numerous. This is like shining a beam up into the Milky Way. Billions upon billions of spores in the air all around us, and they’re ubiquitous, so they’re going up to the ceiling they’re going out the door, they’re doubtless going into my lungs. If you want a graphic demonstration of how prolific mushrooms are, here it is. So this is how most fungi begin life. The mushroom spews out many millions of spores every hour, for as long as it remains above the ground… each of them carrying the potential to be a new fungus. It’s mesmerising to watch, but I want to know exactly what’s going on here and to do that, I’ll need more than a laser light.
Back in the mushroom lab, Patrick Hickey can reveal the hidden mechanism of mushroom birth.
Patrick Hickey “A mushroom, also known as a fruiting body, really is just the reproductive structure of a fungus and its sole purpose is to produce spores. So to look at these in more detail, what I’m going to do is take a very thin section through this mushroom cap and put it onto a microscope slide. The large cylindrical kind of clear part of the cell is the basidium and those little spiky bits protruding from it are called the sterigmata and they hold the spores in place. Now, eventually, when those spores are fully ripened, they’ll drop off into that air space between the gills, and fall down from the mushroom. That whole structure, including the spores, is abouth the width of a human hair, and, remember, these gills are packed with them. They’re completely lined with a layer of these basidia continually producing spores. It;s a production line.”
It’s an extraordinary thought, isn’t it? This tiny object, just a few thousandths of a millimetre long, contain the potentiality for a new mushroom colony.
This constant production line, forming and releasing spores, is exactly what I saw so vividly in action at the mushroom farm. But that’s just one way mushrooms can spread their spores.
Others do it in a completely different way. This is an orange peel fungus, and it’s part of a large group that fire their spores vertically, with exposive results, as we can see here when the action is slowed down 800 times. They’re like geysers erupting.
Patrick Hickey “The spores are incredibly prolific. Throughout the course of a day, each fungus might be capable of producing over a million spores and over the lifetime of that fungus, we’re into the tens to hundreds of millions.”
Well, that’s extraordinary footage. I’ve never, ever seen anything so graphically displaying the way fungi get rid of their spores.
Patrick Hickey “It’s a truly impressive fungus.”
These fungi can reload and fire time and time again, often for many days on end. And how that works was a brilliant discovery made by someone you wouldn’t expect.
Beatrix Potter – Mushroom Biologist
Beatrix Potter is famous for penning The Tales of Peter rabbit, but what’s less well known, is that she was one of the leading mushroom biologists of her time. Both Beatrix Potter and pioneering biologist Arthur Buller spent much of their lives trying to find out how some mushrooms release their spores. They discovered that a tiny drop of fluid, now known as Buller’s drop, forms at the base of every spore. As the spore ripens and begins to detach, the Buller’s drop fuses with a second water droplet that forms at the side of the spore. Like two raindrops joining together on a windowpane, this fusion causes a rapid shift in mass that dislodges the spore in such a spectacular fashion. This microscopic process all takes place in a few millionths of a second and is key to how many fungi reproduce. But of them all, there’s one particular species that’s a record breaker.
Hat Thrower Fungus
You may think that the fastest organism on the planet is a cheetah or maybe a peregrine falcon, but you’d be wrong. Allowing for scale, the speediest organism on the planet is actually a tiny fungus. it grows on top of cowpats. It’s called Pilobolus crystallinus, or the ‘Hat Thrower’ fungus, and no other species demonstrates better the importance of the spore release mechanism.
This little fungus feeds on the dung of herbivores, but when the supply of nutrients from one pile has been exhausted, it needs to move on, and to do that, it has to get out of the dung and onto new blades of grass. That’s the equivalent of you or I trying to throw a tennis ball over the Eiffel Tower. But, then, you or I can’t do this. Using water drop acceleration, these spore capsules, seen as little black hats, can be fired at a speed of up to 40mph in just two millionths of a second, pulling an astonishing 20,000 Gs in the process.
The little “Hat Thrower” fungus is a wonderful example of the sophistication of fungus evolution. It throws its spore body more than a thousand times its own length into clear grass, away from cowpats, so that the cows will come along, graze the grass, incorporate the spores and so propagate another generation. The “Hat Thrower” shows just how ingenious fungi are when it comes to reproduction. They will go to extraordinary lengths to ensure their own future. It’s the key to the fungi have become such a dominant life form with such vast numbers of species all over the planet. And it’s certainly a talent to which humankind owes a great deal.
But as impressive as spore dispersal might be, it’s just the beginning of the fungus’s life story. It’s the next stage that truly reveals why they are so vital to all life on Earth.
