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Hey it's me Destin and welcome back to Smarter Every Day.
If you've ever been stung by a jellyfish you know that it's awful, lemme show you.
So there's two ways that an animal can harm a human chemically right?
The first one is poison. We know what that is, like if I were to eat this jellyfish and it was poisonous and I were to get sick
it's because it is a poisonous animal right?
Now venom is different. Venom is injected into your body. So it's kind of like these hypodermic needles.
If you fill them up with venom and then you were to take that and inject that into your arm, that would be a venomous way of causing pain to your body right?
So wouldn't it be crazy if there was like hypodermic needles built into their tentacles and they could just stab you with them as soon as they rubbed up against you.
Because that's exactly what happens.
Jellyfish tentacles have organelles in them called nematocysts.
They're like little hypodermic needles,
and when you're swimming, and those hypodermic needles brush up against your body,
they stab into you and inject venom. It's insane.
People have never seen these because they're so small you have to have a microscope and they're so fast that you have to use a high speed camera.
So now that we've rounded these two things up, where do we find our jellyfish?
Check it out. I'm at James Cook University in Australia, in Cairns, and here's the deal.
I've got the doctor here that's the world expert in animal venom.
It's pretty cool, let's go check it out.
His name is Dr Jamie Seymour.
So we have a high speed camera here, and we're running HD-SDI video out, and then Richard is recording it realtime,
and then Dr Seymour here is gonna try to trigger a nematocyst, correct?
- Correct.
- And then once you trigger it we're gonna try to catch it on high speed.
- Yep. If you look at an anenome, we've just taken this out of an anenome, and if you poke it in the side..
(Destin) So this isn't a jellyfish.
- Well it's related to jellyfish.
- Close enough. OK. I told everybody wrong, I said we're gonna look at a jellyfish sting..
- It's the same thing! It's the same process!
- Oh is it?
- That's like saying "OK we're gonna work out how a bullet works today, here's an AK-47" and then if I walk in with a Glock, it's the same process.
- You are speaking my language Australia man! [laugh]
- See there you go.
(Destin) So we're still not exactly sure what causes the nematocyst to fire,
but what we do know is if we touch two leads from a 9 volt battery to the tentacle itself we can get some of them to randomly fire, which allows us to record it with a phantom high speed camera.
- Trigger it, trigger, trigger, trigger!
- Here it goes!
[music]
(Destin) How long have you been trying to capture that?
- Oh we could do it for a fair number of years but we never had the camera technology to actually do it at this level before.
The nematocyst, which is a cell organelle, so it's inside a cell, which is a ball with a wound-up hypodermic needle in it.
And we saw it basically discharge, so..
(Destin) And the needle was not rigid necessarily.
- That's correct. Think of it like a garden hose under no pressure,
and then when you apply pressure to it, the whole thing straightens out.
- Got it.
- So what we saw there, it's the whole thing fired off.
You got some sort of idea of how quick that was, but the thing that blew me away was the time lag from when the thing discharged, till when we saw the venom.
- Yeah it was like a third of a second.
- Yeah. We've never seen that before. I mean we've seen venom come out the end of these things, we've never seen that delay, but we've never looked for it.
- You're digging this aren't you?
- Oh this is cool. This is like.. real science.
This is the sort of stuff I get up in the morning for.
- Are you implying that I don't do real science?
- Oh but no, you do the same thing. There are times you get up in the morning, I'm sure, and you just go "I so want to go to work today because I'm gonna find out something new".
- Right.
-Isn't that why you do it?
- Right, it is.
- I mean, seriously I.. I would do this stuff for free. It's the joy of actually coming in and going "I just saw something that nobody else in the world has ever seen before".
- That's kind of selfish.
- Yeah but... But then you can teach people about it.
- That's right, yeah.
- And that's.. ah. Look I've got goose bumps all over me just from that sort of thing. It's just.. It's great. It's exactly why I do this sort of stuff.
- Alright, well thank you very much.
That's Dr Seymour. Venomologist?
- Toxinologist!
- Toxinologist. [laugh]
- Oh man!
- I'm never gonna get it right.
So from now on when you think about jellyfish I hope you don't think about just slimy tentacles dragging poison on your skin.
It's actually an organelle called a nematocyst containing the venom that takes it and actually shoves it. Oohoo.
Into your body, and then injects the venom..
I'm just kidding. I didn't actually squirt that in me, but.. That's pretty intense.
I hope I didn't ruin the beach for you.
The people at James Cook University asked me if I would inform you that they are looking for undergrad and grad students.
They need people to help them figure out how to solve the box jelly venom mystery.
It's a cardiotoxin. It kills the heart but they don't really know how or why.
So if you're interested in studying, go to James Cook University.
I think their motto is like "The explorers of the tropics", which is pretty cool.
Anyway, I'm Destin.
Go check em out. Have a good one.
- Big box jellyfish things have got 800,000 of those things per square centimeter.
- Really?
- That's how small they are.
- Not only do you get to learn about the animals but we physically put you in the lab and give you venom, and go "Here, here's some rattlesnake venom or some box jellyfish venom or some other venom"
and you get to use it on heart cells or blood and things of that nature, and actually physically see the venom doing its thing there and then.
Not too many other subjects allow you to do that, for a whole variety of reasons.
- So is this unique to James Cook University?
- Absolutely.
- Yeah, did you.. and you started it.
- Yeah.
- That's pretty cool.
- It is.
- A little pride in that huh?
- Just.. A lot. [laugh]
コツ:単語をクリックしてすぐ意味を調べられます!

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Jellyfish Stinging in MICROSCOPIC SLOW MOTION - Smarter Every Day 120

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alex 2016 年 12 月 10 日 に公開
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