有個像是來自詹姆斯邦德系列電影的故事
It’s a story straight out of a Bond film.
為BBC工作的保加利亞記者喬治馬科夫是共產主義的叛徒
On September 7th, 1978, Bulgarian journalist Georgi Markov, a communist defector working for the BBC,
1978年9月7日 當他右腿感到輕微的刺痛時 他正走在倫敦的滑鐵盧大橋上
was walking across the Waterloo Bridge in London, when he felt a slight sting in his right thigh.
他回頭看時發現一個男人正從地上撿一把雨傘
He looked behind him and saw a man picking an umbrella up off the ground.
當天晚上 他就開始發燒
By that evening he had developed a fever.
四天後他就去世了
Four days later he was dead.
死亡原因是——中毒
The cause of death: poisoning.
馬科夫被一把傘操控的火丸暗殺 火丸含有世界上最強大的天然毒素
Markov had been assassinated using an umbrella rigged to fire a pellet laced with one of the most powerful natural toxins in the world:
蓖麻毒素
Ricin.
蓖麻毒素是在動物之外發現的最致命的自然物質之一
Ricin is one of the deadliest natural substances that is not found in an animal.
它是在蓖麻植物的種子中發現的
It’s found in the beans of the castor plant.
500微克的這種物質就足以殺死一個人 那僅僅是曲別針萬分之五的質量
Just 500 micrograms of this stuff, that’s 5/10 000 of what a paperclip weighs, is enough to kill a man.
儘管它如此強大 蓖麻毒素距離地球上最毒的自然物質仍差之千裡
And as potent as it is, ricin isn’t even close to being the most poisonous natural substance on Earth.
細菌 植物和真菌上到處都潛伏著毒素
There are poisons that lurk in bacteria, plants, and fungi all over the place,
它們也不僅出現在奇異的熱帶地區或是19世紀70年代的倫敦
and they’re not just found in exotic, tropical locales or, like, 1970s』 London.
這些物質很有可能到處都是 事實上 它們的存在是有好處的
They’re pretty much everywhere, and the fact is, they’re there for good reasons.
但使其毒性如此巨大的化學成分是什麼？
But what is it about their chemical makeup that makes them so poisonous?
它們的毒素是怎樣以致命的效果攻擊人體的？
How do their toxins attack the human body with such deadly efficiency?
以及為什麼我的大腿突然間感到刺痛？
And why does my thigh suddenly feel all tingly?
那是一把雨傘嗎！？
Is that an umbrella!!?
[音樂播放中]
[Music playing]
列舉出自然界中最致命的毒素不僅很恐怖 還是幾乎不可能的
Not only is it morbid to list the most deadly toxins in nature, it’s also nearly impossible.
很多植物 真菌和細菌在被食用 吸入或混入血液時是能夠殺死人的
There are a lot of plants, fungi and bacteria out there capable of killing you if eaten, inhaled, or injected.
而且也有很多因素使準確界定某種物質毒性如何變得困難
And there are also a lot of variables to make it hard to quantify exactly how poisonous something is.
從受害者的年齡到其體內的抗體都可以反映出一種物質毒性如何
Everything from the age of the victim to the antibodies in your system can effect how potent a substance is.
然而 事無絕對
There is however, one exception.
沒有人質疑人類已知的最致命的毒素屬於天然有毒物質 或者說沒有人質疑它是由微小的肉毒梭狀芽孢桿菌產生的
No-one disputes that the most lethal toxic substance known to man natural or otherwise is produced by the tiny bacterium Clostridium botulinum.
你可能因為它造成的疾病——肉毒中毒 而知曉它
You probably know it by the disease it causes, botulism.
肉毒桿菌毒素究竟有多致命呢？
Just how deadly is the botulinum toxin?
專家用來衡量毒素殺傷力的一個方法被稱為「半致命劑量」
One way experts use to measure the lethality of a poison is a method called the 「Lethal dose 50%」,
即能夠殺死一半測試者的劑量
Which is the dose required to kill half the members of a tested population.
顯而易見的是人們無法在人類身上測試 毒理學家常稱此數量為「半致死劑量」
Since, for obvious reasons, you can’t run these tests on humans, toxicologists usually gets this number, often called the LD50,
通過使用一種極其不幸的生物：
by using an endlessly unfortunate creature:
實驗室的老鼠
The laboratory mouse.
半數致死量=毒素質量（毫克）/體重（千克）
LD50 is measured in a ratio of milligrams of toxin to kilograms of bodyweight,
對於肉毒桿菌毒素 半數致死量為一毫微克（十億分之一克）每千克
and in the case of the botulinum toxin it’s about one nanogram, a billionth of a gram, per kilogram.
那意味著一粒沙子大小的肉毒桿菌晶體足以殺死9600個人
That means that a crystal of botulinum the size of a grain of sand, would be enough to kill 9,600 people.
實際上肉毒桿菌十分常見 它們產出的孢子遍布世界上的土壤和水中
The bacteria are actually really common and the spores they produce are found in soil and water all over the world.
問題源於 孢子發育為活細胞時 會產出七種不同的毒素
The problem starts when they germinate into active cells, at which point they begin to produce seven different toxins,
其中的四種對人類來說是致命的
four of which are deadly to humans.
C肉毒桿菌在低氧環境中繁殖 美國每年十到三十起中毒案例被報導
C. botulinum thrives in low-oxygen environments, and the ten to thirty cases reported each year in the U.S.
通常是由不恰當食用罐頭食品造成 因為裝罐時需要抽出氧氣以保存食品
are usually the result of eating improperly canned food, since canning removes oxygen from food to preserve it.
但是如果沒有正確加熱罐頭食品 那些孢子會在德州辣醬罐頭裡徘徊並安家立業
But if the food isn’t heated properly the spores can stick around and set up shop in that can of Texas chili.
肉毒桿菌的孢子也存在於蜂蜜中 如果你吃下它們 它們能夠在你身體裡找到一個超棒的無氧角落存活
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.
兒童和成人都能夠在其發育之前抵禦孢子 但嬰兒不行
Kids and adults can ward off these spores before they germinate, but infants cannot,
這就是為什麼12個月以下的嬰兒不能食用蜂蜜
which is why babies under 12 months old should never eat honey.
孢子之所以有毒是因為它們會將神經毒素作為廢物排出
The spores are poisonous because they secrete a neurotoxin as a waste product.
它能夠阻礙控制肌肉收縮的神經遞質——乙醯膽鹼的釋放
It works by blocking the release of a neurotransmitter called acetylcholine, which controls muscle contractions.
這十分有效地使受害者的每一塊肌肉變得無力
This effectively makes every muscle in the victim’s body go limp.
如果幾天之內不注射抗毒素血清 受害者將窒息身亡
Within several days without antitoxin the victim will asphyxiate from the inability to breathe.
當然 多虧了科學和那些可憐的實驗室老鼠 是有這種抗毒素血清
But yes, thanks to science, and all those poor lab mice, there is an antitoxin.
但是 託馬修·奧菲拉的福 細菌會進化到向其宿主釋放劇毒的原因究竟是什麼？
But why in the name of Mathieu Orfila would a bacterium evolve to fart the deadliest poison on earth into its host?
答案仍是一個謎團
The answer remains a mystery.
有理論認為毒素目標不是宿主 而是「競爭細菌」
One theory is that the toxins are not aimed at the host, but rather at competitor bacteria.
它們創造出一個良性細菌不能存活的環境 使惡性細菌有機會傳播
They create conditions where benign bacteria cannot survive, giving the evil bacteria a chance to spread.
在這種情況下 宿主人類常因此患病
The host, in this case a human, is often just in the way of this process.
與肉毒桿菌相比 食用氰化物就像吃橡皮泥一樣
So compared to the botulinum toxins, cyanide is like eating play dough.
逗你的
Well, not really.
千萬不要誤食氰化物！
Do not eat cyanide!
那不僅會使你毀容 氰化物還是世界上生效最快的毒藥
Not only will it kill your face, it’s also one of the most rapidly acting poisons in the world.
它存在於香菸煙霧和燃燒的塑料中 還存在於大量天然食品中 如扁桃仁與杏和蘋果的種子中
It’s found in cigarette smoke, burning plastics, also a surprising number of natural foods including almonds and the seeds of apricots and apples.
氰化鈉的半數致死量通常是每千克體重6.4毫克
The LD50 of sodium cyanide, a common form, is 6.4 mg per kg of bodyweight,
致命性比肉毒桿菌低了超過六百萬倍
or over 6 million times less deadly than botulinum.
但據說從古羅馬暴君尼祿到阿加莎·克裡斯蒂 氰化鈉都是流行且有效的治死工具
But that said, it’s been a popular and effective tool of death for everyone from Emperor Nero to Agatha Christie.
氰化物中氰鍵是碳氮三鍵
Cyanide is a carbon atom triple bonded to a nitrogen atom.
使它成為如此有力的殺手的是它能結合你細胞內線粒體中的蛋白質 而蛋白質是能夠使細胞運轉的微小發電站
What makes it such a fast killer is that it binds to proteins in your cell’s mitochondria, the tiny power plants that keep your cells going,
氰化物通過抑制細胞呼吸 基本上使人體在細胞水平窒息
and keeps them from using oxygen, basically asphyxiating the body at a cellular level.
一些水果和堅果的確含有氰化物
It is true that some fruits and nuts contain cyanide.
比方說蘋果的種子 它含有一種化學物質可以在氰化物和消化酶接觸時釋放它
Apple seeds for instance contain a chemical that releases cyanide when it comes into contact with digestive enzymes.
這是一個阻止生物消化掉所有種子的好方法 並且留下的毒素將不足以殺死它們 或者我們
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.
但我猜我不會想要吃掉滿滿一碗蘋果種子
Though I guess I wouldn’t make a point of like eating a bowl of apple seeds.
好消息是如果你碰巧氰化物中毒 維他命B12可以幫助你（解毒）
The good news is that if you happen to suffer from cyanide poisoning, there’s always vitamin B12.
你在商店裡買到的B12實際上含有氰化物作為其華麗複雜的分子結構的一部分
The B12 that you get at the store actually contains cyanide as part of its gloriously complex molecular structure,
所以高劑量的維他命B12攝入可以逐個吸收你「中毒線粒體」中的氰化物
so high doses of a precursor to the vitamin can literally pull the cyanide off of your poisoned mitochondria,
然後你只需要排除B12形式的毒素
and then you just pee out the poison in the form of B12.
現在繼續討論我們的保加利亞朋友
Now, back to our Bulgarian friend.
殺死馬科夫的蓖麻植物原產於非洲東部
Well the castor plant that killed him is next on our list. It’s native to East Africa,
但它生長在更加溫暖的很多地方 像是美國西南部
but grows pretty much anywhere it’s warm, including the southwestern United States.
它產生的蓖麻毒素是其種子裡的一種蛋白質
The toxin it produces, ricin, is a protein found in the castor bean,
但毒素本身源於種子磨製成油後剩下的糊狀物
but the poison itself is made from the mash that’s left over after grinding the beans into oil.
在加熱油時蓖麻毒素蛋白變性或失活 使其無害
When the oil is heated the ricin protein denatures or changes shape, which renders it harmless.
所以廣泛用作瀉藥的油中不含毒素
So the toxin doesn’t end up in the oil itself, which is used widely as a laxative.
或許以前是這樣 現在沒有那麼廣泛了
Or used to be. Not so much anymore.
因為噁心
Cause gross.
但一旦被吸入 攝取或注射 未經處理的蓖麻毒素隨時可能被身體細胞吸收
But when inhaled, ingested, or injected, untreated ricin is readily absorbed by the body’s cells.
一旦進入細胞 它會使核糖體滅活 核糖體能夠製造細胞生長增殖所需的蛋白質
Once inside it inactivates the ribosomes, which manufacture proteins that your cells need to survive and reproduce,
一旦蛋白質鏈停止 生命也將終結
and once the protein train stops, life stops.
僅僅是一個蓖麻毒素分子每分鐘就能夠抑制1500個核糖體活動 因為它會殺死細胞
Just a single ricin molecule is capable of inactivating 1,500 ribosomes per minute as it kills the cell.
幾小時內你將感受到毒素效果 但蓖麻毒素通常是慢性毒藥 1-3天才能造成死亡
You may feel the effects within a few hours, but ricin is generally a slow acting poison, taking 1-3 days to cause death.
因此數年來它流行於想要開脫罪名的刺殺者中
Hence its popularity with assassins over the years who want to distance themselves from their crime.
發現於馬科夫腿部的微小鉑插頭含有兩個鑽入的槽口 每個都能容納1/5毫克的毒素
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.
但已足夠殺死馬科夫或者其餘任何人
But that was more than enough to kill Markov or any other human.
蓖麻毒素的毒性可根據其進入身體的方式而改變
And the toxicity of ricin can change depending on how it enters the body.
口服時它的半數致死量是每千克體重 20毫克
Taken orally its LD50 is about 20 milligrams per kilogram of bodyweight,
大約需要8顆蓖麻種子來提取它
about 8 castor beans worth of the poison,
但當像馬科夫一樣注入體內時 半數致死量僅為每千克小小的
一毫克
but if it’s injected, like the way Markov got it, it’s just 1 tiny microgram per kilogram.
可悲的是 蓖麻毒素的解毒劑仍處於初期發展中 但由於蓖麻毒素致死需要數日
Antidotes to ricin, sad to say, are still in the early stages of development, but because ricin takes several days to kill,
人類正在研究能夠阻止它進入體內其他細胞的核糖體的化合物
compounds are being investigated that can block it from reaching ribosomes in new cells in the body.
奇怪的是人們也在癌症治療方面研究 蓖麻毒素
And strangely enough ricin is also being investigated as a possible cancer treatment,
因為它能夠觸發細胞中蛋白質的細胞凋亡機制
because of its ability to trigger that protein-stopping self destruct mechanism in cells,
當然包括癌細胞
including, of course, cancer cells.
如果你曾見過馬錢子鹼樹 當然它確實存在
Now, if you ever come across a strychnine tree, and yes there is such a thing,
我建議大家儘可能遠離它
my advice is to stay as far away as possible.
它源自印度和東南亞 它的樹皮含有一種叫做二甲馬錢子鹼的毒素
It’s native to India and Southeast Asia, and its bark contains a poison called brucine,
但真正的致命性源於這種樹綠色到橘色的圓形果實
but the real lethality comes from the trees round green-to-orange fruit
它的果實含有生物鹼士的寧
which contains the alkaloid strychnine.
在這兩種可憐的生物 鴿子和老鼠身上做的實驗可確定 口服時士的寧的
半數致死量在每千克體重3-14毫克之間
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,
致命程度與蓖麻毒素相似
which puts it in a similar category of lethalness as ricin.
但威脅在於一種能夠影響控制肌肉收縮的脊髓神經的神經毒素
But the threat here is a neurotoxin that affects the nerves in the spinal cord that control muscle contraction.
本質上它阻礙控制神經信號的化學物質進入肌肉
Essentially it blocks the chemicals that control nerve signals to muscle.
通過阻塞那種化學物質 士的寧使人體肌肉持續收縮
By blocking that chemical, strychnine puts your muscles in a state of constant stimulation,
造成癲癇直到筋疲力盡甚至呼吸衰竭 這一切僅發生在30分鐘內
causing seizures until the point of exhaustion and respiratory failure, in as little as 30 minutes.
這聽起來可不像是一個舒適的死亡方式
This does not sound like a pleasant way to die.
最後 一個完整的天然毒素花名冊一定不會少了真菌
Finally, no roster of natural poisons would be complete without a visit to the kingdom fungi,
因為儘管上千種真菌中只有少數有毒
because although few of its thousands of species are poisonous, some of the ones that are
其中的一些含有的毒素的劇毒程度堪比肉毒中毒 它叫做鵝膏毒素
contain toxins that would give botulism a run for its money, called amatoxins.
其中兩種最危險的蕈類含有的毒素叫做 鵝膏蕈鹼
The two most dangerous of these mushrooms contain the most lethal poison of its kind, called amanitin,
它們也有不那麼神秘的名字 叫做死亡帽子和破壞天使
and they have the not so cryptic names of Death Cap and Destroying Angel.
口服時蕈類含有的鵝膏蕈鹼的半數致死量為每千克體重0.1-0.2毫克
The oral LD50 of amanitin containing mushrooms is between 0.1 and 0.2 milligrams per kilogram.
所以我們說它的毒性至少是士的寧的30倍
So we’re talking at least 30 times deadlier than strychnine.
鵝膏毒素本質上是胺基酸環
Amatoxins are essentially rings of amino acids that interfere with enzymes that,
幹擾酶同樣是負責細胞內生命必須的蛋白質的生產
again are responsible for the production of lifegiving proteins in your cells,
但這種情況下它們的專能目標是 肝臟和腎臟細胞
but here they specifically target your liver and kidney cells.
它們如此危險的部分原因是攝入毒素後6-24小時才出現症狀
Part of the reason they’re so dangerous is that symptoms are delayed for 6 to 24 hours after ingestion
所以受害者肝腎不適時僅僅知道身體出問題了
so victims only know there’s something wrong when their liver and kidneys begin to fail,
造成的嘔吐腹瀉常在急診室被誤診為流感
causing vomiting and diarrhea, which is often mistaken in emergency rooms as the flu,
另一個原因是中毒常常是致命的
another reason the poisoning is often fatal.
美國大多數這類死亡案例都是由於亞洲移民錯識蕈類
Most of these deaths in the U.S. are from the misidentification of mushrooms by immigrants from Asia,
亞洲不存在這些特殊的真菌種類 而且它們擁有看起來可以食用的外表
where these particular species of fungi don’t exist and instead have quite edible lookalikes.
在及早發現的情況下 大劑量的水飛薊提取物可以阻止最嚴重的傷害
In cases that are caught early enough, massive doses of milk thistle extract can stop the worst of the damage –
提取物中含有能阻塞肝臟細胞吸收毒素的化合物
the extract contains chemicals that block the uptake of the toxin in liver cells.
但在最壞的情況下 受害者只能通過肝臟移植獲救
But in the worst cases the victim can only be saved by a liver transplant.
我差不多說完了 既然我是一個對一切事情偏執狂熱的傢伙 從奇怪的男人和雨傘
Now I should probably stop, now that I’m just completely paranoid about everything from strange men with umbrellas,
到世界上所有外表美麗的蕈類
to all of the formerly beautiful mushrooms in the world.
好消息是 科學家和實驗室老鼠正致力於發展這些最毒的天然毒性物質的抗毒素
The good news is that scientists, and lab mice, have been working hard developing anti-toxins to these most poisonous natural substances,
所以即使遭遇其中之一 我們也許不會因此喪命
so that if we do come across one of them, we might not die.
而且少數情況下 這些劇毒物質將會在某一天拯救我們
例如 針對癌細胞
And in a very few cases these terribly toxic substances may even be used to save us one day, by targeting cancer cells.