It's a story straight out of a Bond film.
有个像是来自詹姆斯邦德系列电影的故事
On September 7th, 1978, Bulgarian journalist Georgi Markov, a communist defector working for the BBC,
为BBC工作的保加利亚记者乔治马科夫是共产主义的叛徒
was walking across the Waterloo Bridge in London, when he felt a slight sting in his right thigh.
1978年9月7日 当他右腿感到轻微的刺痛时 他正走在伦敦的魂断蓝桥上
He looked behind him and saw a man picking an umbrella up off the ground.
他回头看时发现一个男人正从地上捡一把雨伞
By that evening he had developed a fever. Four days later he was dead. The cause of death: poisoning.
当天晚上 他就开始发烧 四天后他就去世了 死亡原因是――中毒
Markov had been assassinated using an umbrella rigged to fire a pellet laced with one of the most powerful natural toxins in the world:
马科夫被一把伞操控的火丸暗杀，火丸含有世界上最强大的天然毒素
Ricin. Ricin is one of the deadliest natural substances that is not found in an animal.
蓖麻毒素 蓖麻毒素是在动物之外发现的最致命的自然物质之一
It's found in the beans of the castor plant.
它是在蓖麻植物的种子中发现的
Just 500 micrograms of this stuff, that's 5/10 000 of what a paperclip weighs, is enough to kill a man.
500微克的这种物质就足以杀死一个人 那仅仅是曲别针万分之五的质量
And as potent as it is, ricin isn't even close to being the most poisonous natural substance on Earth.
尽管它如此强大 蓖麻毒素距离地球上最毒的自然物质仍差之千里
There are poisons that lurk in bacteria, plants, and fungi all over the place,
细菌、植物和真菌上到处都潜伏着毒素
and they're not just found in exotic, tropical locales or, like, 1970s' London.
它们也不仅出现在奇异的热带地区或是19世纪70年代的伦敦
They're pretty much everywhere, and the fact is, they're there for good reasons.
这些物质很有可能到处都是 事实上 它们的存在是有好处的
But what is it about their chemical makeup that makes them so poisonous?
但使其毒性如此巨大的化学成分是什么？
How do their toxins attack the human body with such deadly efficiency?
它们的毒素是怎样以致命的效果攻击人体的？
And why does my thigh suddenly feel all tingly? Is that an umbrella!!?
以及为什么我的大腿突然间感到刺痛？ 那是一把雨伞吗！？
Not only is it morbid to list the most deadly toxins in nature, it's also nearly impossible.
列举出自然界中最致命的毒素不仅很恐怖 还是几乎不可能的
There are a lot of plants, fungi and bacteria out there capable of killing you if eaten, inhaled, or injected.
很多植物、真菌和细菌在被食用、吸入或混入血液时是能够杀死人的
And there are also a lot of variables to make it hard to quantify exactly how poisonous something is.
而且也有很多因素使准确界定某种物质毒性如何变得困难
Everything from the age of the victim to the antibodies in your system can effect how potent a substance is.
从受害者的年龄到其体内的抗体都可以反映出一种物质毒性如何
There is however, one exception.
然而 事无绝对
No-one disputes that the most lethal toxic substance known to man natural or otherwise is produced by the tiny bacterium Clostridium botulinum.
没有人质疑人类已知的最致命的毒素属于自然物质，或者说没有人质疑它是由微小的肉毒梭状芽孢杆菌产生的
You probably know it by the disease it causes, botulism.
你可能因为它造成的疾病--肉毒中毒而知晓它
Just how deadly is the botulinum toxin?
肉毒杆菌毒素究竟有多致命呢？
One way experts use to measure the lethality of a poison is a method called the "Lethal dose 50%",
专家用来衡量毒素杀伤力的一个方法被称为“半致命剂量”
Which is the dose required to kill half the members of a tested population.
即能够杀死一半测试者的剂量
Since, for obvious reasons, you can't run these tests on humans, toxicologists usually gets this number, often called the LD50,
显而易见的是人们无法在人类身上测试 毒理学家常称此数量为半致死剂量
by using an endlessly unfortunate creature: The laboratory mouse.
通过使用一种极其不幸的生物：实验室的老鼠
LD50 is measured in a ratio of milligrams of toxin to kilograms of bodyweight,
半数致死量=毒素质量（毫克）/体重（千克）
and in the case of the botulinum toxin it's about one nanogram, a billionth of a gram, per kilogram.
对于肉毒杆菌毒素 半数致死量为一毫微克（十亿分之一克）每千克
That means that a crystal of botulinum the size of a grain of sand, would be enough to kill 9,600 people.
那意味着一粒沙子大小的肉毒杆菌晶体足以杀死9600个人
The bacteria are actually really common and the spores they produce are found in soil and water all over the world.
实际上肉毒杆菌十分常见 它们产出的孢子遍布世界上的土壤和水中
The problem starts when they germinate into active cells, at which point they begin to produce seven different toxins,
问题源于孢子发育为活细胞时会产出七种不同的毒素
four of which are deadly to humans.
其中的四种对人类来说是致命的
C. botulinum thrives in low-oxygen environments, and the ten to thirty cases reported each year in the U.S.
C肉毒杆菌在低氧环境中繁殖 美国每年十到三十起中毒案例被报道
are usually the result of eating improperly canned food, since canning removes oxygen from food to preserve it.
通常是由不恰当食用罐头食品造成 因为装罐时需要抽出氧气以保存食品
But if the food isn't heated properly the spores can stick around and set up shop in that can of Texas chili.
但是如果没有正确加热罐头食品 那些孢子会在德州辣酱罐头里徘徊并安家立业
Botulinum spores can also be found in honey, and if you eat them they can find a nice oxygen free nook of your body to hang out in.
肉毒杆菌的孢子也存在于蜂蜜中，如果你吃下它们 它们能够在你身体里找到一个超棒的无氧角落存活
Kids and adults can ward off these spores before they germinate, but infants cannot,
儿童和成人都能够在其发育之前抵御孢子 但婴儿不行
which is why babies under 12 months old should never eat honey.
这就是为什么12个月以下的婴儿不能食用蜂蜜
The spores are poisonous because they secrete a neurotoxin as a waste product.
孢子之所以有毒是因为它们会将神经毒素作为废物排出
It works by blocking the release of a neurotransmitter called acetylcholine, which controls muscle contractions.
它能够阻碍控制肌肉收缩的神经递质--乙酰胆碱的释放
This effectively makes every muscle in the victim's body go limp.
这十分有效地使受害者的每一块肌肉变得无力
Within several days without antitoxin the victim will asphyxiate from the inability to breathe.
如果几天之内不注射抗毒素血清 受害者将窒息身亡
But yes, thanks to science, and all those poor lab mice, there is an antitoxin.
当然 多亏了科学和那些可怜的实验室老鼠 是有这种抗毒素血清
But why in the name of Mathieu Orfila would a bacterium evolve to fart the deadliest poison on earth into its host?
但是 托马修·奥菲拉的福 细菌会进化到向其宿主释放剧毒的原因究竟是什么？
The answer remains a mystery.
答案仍是一个谜团
One theory is that the toxins are not aimed at the host, but rather at competitor bacteria.
有理论认为毒素目标不是宿主 而是竞争细菌
They create conditions where benign bacteria cannot survive, giving the evil bacteria a chance to spread.
它们创造出一个良性细菌不能存活的环境 使恶性细菌有机会传播
The host, in this case a human, is often just in the way of this process.
在这种情况下 宿主人类常因此患病
So compared to the botulinum toxins, cyanide is like eating play dough.
与肉毒杆菌相比 食用氰化物就像吃橡皮泥一样
Well, not really. Do not eat cyanide!
逗你的 千万不要误食氰化物！
Not only will it kill your face, it's also one of the most rapidly acting poisons in the world.
那不仅会使你毁容 氰化物还是世界上生效最快的毒药
It's found in cigarette smoke, burning plastics,
它存在于香烟烟雾和燃烧的塑料中
also a surprising number of natural foods including almonds and the seeds of apricots and apples.
还存在于大量天然食品中 如扁桃仁与杏和苹果的种子中
The LD50 of sodium cyanide, a common form, is 6.4 mg per kg of bodyweight, or over 6 million times less deadly than botulinum.
氰化钠的半数致死量通常是每千克体重6.4毫克 致命性比肉毒杆菌低了超过六百万倍
But that said, it's been a popular and effective tool of death for everyone from Emperor Nero to Agatha Christie.
但据说从古罗马暴君尼禄到阿加莎·克里斯蒂 氰化钠都是流行且有效的治死工具
Cyanide is a carbon atom triple bonded to a nitrogen atom.
氰化物中氰键是碳氮三键

What makes it such a fast killer is that it binds to proteins in your cell's mitochondria,
使它成为如此有力的杀手的是它能结合你细胞内线粒体中的蛋白质
the tiny power plants that keep your cells going,
而蛋白质是能够使细胞运转的微小发电站
and keeps them from using oxygen, basically asphyxiating the body at a cellular level.
氰化物通过抑制细胞呼吸 基本上使人体在细胞水平窒息
It is true that some fruits and nuts contain cyanide.
一些水果和坚果的确含有氰化物
Apple seeds for instance contain a chemical that releases cyanide when it comes into contact with digestive enzymes.
比方说苹果的种子 它含有一种化学物质可以在氰化物和消化酶接触时释放它
This is a good way to deter critters from digesting up all your seeds if you're a fruit, but there's not enough poison to kill them, or us.
这是一个阻止生物消化掉所有种子的好方法 并且留下的毒素将不足以杀死它们，或者我们
Though I guess I wouldn't make a point of like eating a bowl of apple seeds.
但我猜我不会想要吃掉满满一碗苹果种子
The good news is that if you happen to suffer from cyanide poisoning, there's always vitamin B12.
好消息是如果你碰巧氰化物中毒 维他命B12可以帮助你
The B12 that you get at the store actually contains cyanide as part of its gloriously complex molecular structure,
你在商店里买到的B12实际上含有氰化物作为它华丽复杂的分子结构的一部分
so high doses of a precursor to the vitamin can literally pull the cyanide off of your poisoned mitochondria,
所以高剂量的维他命摄入可以逐个吸收你中毒线粒体中的氰化物
and then you just pee out the poison in the form of B12.
然后你只需要排除B12形式的毒素
Now, back to our Bulgarian friend.
现在继续讨论我们的保加利亚朋友
Well the castor plant that killed him is next on our list. It's native to East Africa,
杀死马科夫的蓖麻植物原产于非洲东部
but grows pretty much anywhere it's warm, including the southwestern United States.
但它生长在更加温暖的很多地方 像是美国西南部
The toxin it produces, ricin, is a protein found in the castor bean,
它产生的蓖麻毒素是其种子里的一种蛋白质
but the poison itself is made from the mash that's left over after grinding the beans into oil.
但毒素本身源于种子磨制成油后剩下的糊状物
When the oil is heated the ricin protein denatures or changes shape, which renders it harmless.
在加热油时蓖麻毒素蛋白变性或失活 使其无害
So the toxin doesn't end up in the oil itself, which is used widely as a laxative.
所以广泛用作泻药的油中不含毒素
Or used to be. Not so much anymore. Cause gross.
或许以前是这样 现在没有那么广泛了 因为恶心
But when inhaled, ingested, or injected, untreated ricin is readily absorbed by the body's cells.
但一旦被吸入、摄取或注射 未经处理的蓖麻毒素随时可能被身体细胞吸收
Once inside it inactivates the ribosomes, which manufacture proteins that your cells need to survive and reproduce,
一旦进入细胞 它会使核糖体灭活 核糖体能够制造细胞生长增殖殖所需的蛋白质
and once the protein train stops, life stops.
一旦蛋白质链停止 生命也将终结
Just a single ricin molecule is capable of inactivating 1,500 ribosomes per minute as it kills the cell.
仅仅是一个蓖麻毒素分子每分钟就能够抑制1500个核糖体活动 因为它会杀死细胞
You may feel the effects within a few hours, but ricin is generally a slow acting poison, taking 1-3 days to cause death.
几小时内你将感受到毒素效果 但蓖麻毒素通常是慢性毒药 1-3天才能造成死亡
Hence its popularity with assassins over the years who want to distance themselves from their crime.
因此数年来它流行于想要开脱罪名的刺杀者中
The tiny platinum plug found in Markov's leg had two tiny channels drilled into it, each able to hold about 1/5 of a milligram of the poison.
发现于马科夫腿部的微小铂插头含有两个钻入的槽口 每个都能容纳1/5毫克的毒药
But that was more than enough to kill Markov or any other human.
但已足够杀死马科夫或者任何一个人
And the toxicity of ricin can change depending on how it enters the body.
蓖麻毒素的毒性可根据其进入身体的方式而改变
Taken orally its LD50 is about 20 milligrams per kilogram of bodyweight, about 8 castor beans worth of the poison,
口服时它的半数致死量是每千克体重20毫克 大约需要8颗蓖麻种子来提取
but if it's injected, like the way Markov got it, it's just 1 tiny microgram per kilogram.
但当像马科夫一样注入体内时 半数致死量仅为每千克小小的一毫克
Antidotes to ricin, sad to say, are still in the early stages of development, but because ricin takes several days to kill,
可悲的是 蓖麻毒素的解毒剂仍处于初期发展中 但由于蓖麻毒素致死需要数日
compounds are being investigated that can block it from reaching ribosomes in new cells in the body.
人类正在研究能够阻止它进入体内其他细胞的核糖体的化合物
And strangely enough ricin is also being investigated as a possible cancer treatment,
奇怪的是人们也在癌症治疗方面研究蓖麻毒素
because of its ability to trigger that protein-stopping self destruct mechanism in cells, including, of course, cancer cells.
因为它能够触发细胞中蛋白质的自我破坏机制 当然包括癌细胞
Now, if you ever come across a strychnine tree, and yes there is such a thing, my advice is to stay as far away as possible.
如果你曾见过马钱子碱树 当然它确实存在 我建议大家尽可能远离它
It's native to India and Southeast Asia, and its bark contains a poison called brucine,
它源自印度和东南亚 它的树皮含有一种叫做二甲马钱子碱的毒素
but the real lethality comes from the trees round green-to-orange fruit which contains the alkaloid strychnine.
但真正的致命性源于这种树绿色到橘色的圆形果实 它的果实含有生物碱士的宁
Tests on both sad pigeons and sad rats have pegged the LD50 for strychnine at between 3 and 14 milligram per kilograms when taken orally,
在可怜的鸽子和老鼠身上做的实验可确定口服时士的宁的半数致死量在每千克体重3-14毫克之间
which puts it in a similar category of lethalness as ricin.
致命程度与蓖麻毒素相似
But the threat here is a neurotoxin that affects the nerves in the spinal cord that control muscle contraction.
但威胁在于一种能够影响控制肌肉收缩的脊髓神经的神经毒素
Essentially it blocks the chemicals that control nerve signals to muscle.
本质上它阻碍控制神经信号的化学物质进入肌肉
By blocking that chemical, strychnine puts your muscles in a state of constant stimulation,
通过阻塞那种化学物质 士的宁使人体肌肉持续收缩
causing seizures until the point of exhaustion and respiratory failure, in as little as 30 minutes.
造成癫痫直到筋疲力尽甚至呼吸衰竭 这一切仅发生在30分钟内
This does not sound like a pleasant way to die.
这听起来可不像是一个舒适的死亡方式
Finally, no roster of natural poisons would be complete without a visit to the kingdom fungi,
最后 一个完整的天然毒素花名册一定不会少了真菌
because although few of its thousands of species are poisonous,
因为尽管上千种真菌中只有少数有毒
some of the ones that are contain toxins that would give botulism a run for its money, called amatoxins.
其中的一些含有的毒素的剧毒程度堪比肉毒中毒 它叫做鹅膏毒素
The two most dangerous of these mushrooms contain the most lethal poison of its kind, called amanitin,
其中两种最危险的蕈类含有的毒素叫做鹅膏蕈碱
and they have the not so cryptic names of Death Cap and Destroying Angel.
它们也有不那么神秘的名字 叫做死亡帽子和破坏天使
The oral LD50 of amanitin containing mushrooms is between 0.1 and 0.2 milligrams per kilogram.
口服时蕈类含有的鹅膏蕈碱的半数致死量为每千克体重0.1-0.2毫克
So we're talking at least 30 times deadlier than strychnine.
所以我们说它的毒性至少是士的宁的30倍
Amatoxins are essentially rings of amino acids that interfere with enzymes that,
鹅膏毒素本质上是干扰酶的氨基酸环
again are responsible for the production of lifegiving proteins in your cells,
酶同样是负责细胞内生命必须的蛋白质的生产
but here they specifically target your liver and kidney cells.
但这种情况下它们的专能目标是肝脏和肾脏细胞
Part of the reason they're so dangerous is that symptoms are delayed for 6 to 24 hours after ingestion
它们如此危险的部分原因是摄入毒素后6-24小时才出现症状
so victims only know there's something wrong when their liver and kidneys begin to fail,
所以受害者肝肾不适时仅仅知道身体出问题了
causing vomiting and diarrhea, which is often mistaken in emergency rooms as the flu, another reason the poisoning is often fatal.
造成的呕吐腹泻常在急诊室被误诊为流感 另一个原因是中毒常常是致命的
Most of these deaths in the U.S. are from the misidentification of mushrooms by immigrants from Asia,
美国大多数这类死亡案例都是由于亚洲移民错识蕈类
where these particular species of fungi don't exist and instead have quite edible lookalikes.
亚洲不存在这些特殊的真菌种类 而且它们拥有看起来可以食用的外表
In cases that are caught early enough, massive doses of milk thistle extract can stop the worst of the damage -
在及早发现的情况下 大剂量的水飞蓟提取物可以阻止最严重的伤害
the extract contains chemicals that block the uptake of the toxin in liver cells.
提取物中含有能阻塞肝脏细胞吸收毒素的化合物
But in the worst cases the victim can only be saved by a liver transplant.
但在最坏的情况下 受害者只能通过肝脏移植获救
Now I should probably stop, now that I'm just completely paranoid about everything from strange men with umbrellas,
我差不多说完了 我只是一个对一切事情偏执狂热的家伙 从带着雨伞奇怪的男人
to all of the formerly beautiful mushrooms in the world.
到世界上所有外表美丽的蕈类
The good news is that scientists, and lab mice, have been working hard developing anti-toxins to these most poisonous natural substances,
好消息是科学家和实验室老鼠正致力于发展这些最毒的自然物质的抗毒素
so that if we do come across one of them, we might not die.
所以即使遭遇其中之一 我们也许不会丧命
And in a very few cases these terribly toxic substances may even be used to save us one day, by targeting cancer cells.
而且少数情况下 这些剧毒物质可能在某一天拯救我们 针对癌细胞
So, thank you for watching this episode of SciShow. If you have any questions, comments or suggestions,
感谢您观看这期Sicshow 如果您有任何问题、意见或建议
we're on Facebook and Twitter, and of course down in the comments below.
请通过脸书和推特联系我们 当然也可以通过下方的评论
And if you want to keep getting smarter with us here at SciShow, you can go to youtube.com/scishow, and subscribe.
如果您想和我们一起变得越来越聪明 欢迎点击youtube.com/scishow订阅我们