Why do we harvest horseshoe crab blood? - Elizabeth Cox

翻译人员: xiao gu 校对人员: Sylvia He

During the warmer months, especially at night during the full moon,

在天气温暖的季节，尤其是月圆之夜，

horseshoe crabs emerge from the sea to spawn.

鲎从海里游上沙滩产卵。

Waiting for them are teams of lab workers

等待它们的是若干组 实验室的研究员，

who capture the horseshoe crabs by the hundreds of thousands,

他们捕获成百上千的鲎，

take them to labs,

带回实验室，

harvest their cerulean blood,

采集鲎的深蓝色血液，

then return them to the sea.

再把它们放回大海。

Oddly enough, we capture horseshoe crabs on the beach

奇怪的是， 我们在海边抓鲎，

because that's the only place we know we can find them.

因为这是据我们所知 唯一能找到它们的地方。

A female horseshoe crab lays as many as 20 batches of up to 4,000 eggs

雌鲎每年在海边能产多至 20 批，

on her annual visit to the beach.

每批多至 4000 个卵，

When the eggs hatch,

这些卵孵化后，

the juvenile horseshoe crabs often stay near shore,

幼鲎通常留在近海处

periodically shedding their shells as they grow.

定期蜕壳。

Once they leave these shallow waters,

它们一旦离开浅海，

they don't return until they reach sexual maturity ten years later.

就会在 10 年后，性成熟时才返回。

Despite our best efforts, we don't know where they spend those years.

人们经过努力研究，却仍然 不知道它们在此期间如何生活。

Though we've spotted the occasional horseshoe crab

虽然我们也偶然

as deep as 200 meters below the ocean's surface,

在海平面下 200 米处 发现过一两个鲎，

we only see large groups of adults when they come ashore to spawn.

通常在成年鲎返回海滩时， 我们才能找到成群的鲎。

Horseshoe crab blood contains cells called amebocytes

鲎血中含有使它们

that protect them from infection by viruses,

免受病毒、真菌

fungi,

和细菌感染的

and bacteria.

阿米巴样细胞。

Amebocytes form gels around these invaders

这种细胞和入侵者反应后会分泌

to prevent them from spreading infections.

可防止感染扩散的凝胶。

This isn't unusual.

这很寻常，

All animals have protective immune systems.

所有动物都有免疫系统。

But horseshoe crab amebocytes are exceptionally sensitive

但是鲎的阿米巴样细胞 对于细菌内毒素

to bacterial endotoxins.

特别敏感。

Endotoxins are molecules from the cell walls of certain bacteria,

内毒素来自某些细菌的细胞壁，

including E. coli.

包括大肠杆菌。

Large amounts of them are released when bacterial cells die,

细菌死亡时大量释放内毒素，

and they can make us sick if they enter the blood stream.

进入血液内的内毒素会使我们生病。

Many of the medicines and medical devices we rely on can become contaminated,

我们依赖的大量药品 和医疗器械可能被污染，

so we have to test them before they touch our blood.

所以在使用前，我们需要

We do have tests called Gram stains that detect bacteria,

用革兰氏染色试验 来测试细菌的存在，

but they can't recognize endotoxins

但是革兰氏染色不能识别内毒素。

which can be there even when bacteria aren't present.

即使没有细菌， 内毒素仍有可能存在。

So scientists use an extract called LAL

所以科学家使用一个叫 LAL 的

produced from harvested horseshoe crab blood

鲎血提取物

to test for endotoxins.

来测试内毒素。

They add LAL to a medicine sample, and if gels form,

他们把 LAL 加入样本中， 如果凝胶形成，

bacterial endotoxins are present.

说明样本中存在细菌内毒素。

Today, the LAL test is used so widely

如今，LAL 测试被广泛使用，

that millions of people who've never seen a horseshoe crab

即使成千上万的人 从来没有见过鲎，

have been protected by their blood.

他们也受益于鲎血。

If you've ever had an injection, that probably includes you.

如果你曾经接受过药物注射， 你可能就是其中之一。

How did horseshoe crabs end up with such special blood?

鲎为什么会有这么特殊的血液呢？

Like other invertebrates,

像其他无脊椎动物一样，

the horseshoe crab has an open circulatory system.

鲎有开放循环系统。

This means their blood isn't contained in blood vessels, like ours.

和人类不同， 它们的血液 没有封闭在血管中。

Instead, horseshoe crab blood flows freely through the body cavity

相反，鲎血在体腔中自由流动，

and comes in direct contact with tissues.

直接抵达身体组织。

If bacteria enters their blood, it can quickly spread over a large area.

如果细菌进入体内， 很快就会蔓延至全身。

Pair this vulnerability

而且鲎在海洋中

with the horseshoe crab's bacteria-filled ocean and shoreline habitats,

和海岸的栖息地充斥着细菌，

and it's easy to see why they need such a sensitive immune response.

所以它们需要敏感的免疫系统。

Horseshoe crabs survived mass extinction events

鲎能在毁灭了地球 90% 的生命，

that wiped out over 90% of life on Earth and killed off the dinosaurs,

包括恐龙的大规模 灭绝事件中存活下来。

but they're not invincible.

但鲎也有天敌。

And the biggest disruptions they've faced in millions of years come from us.

数百万年来， 它们最大的挑战来自人类。

Studies have shown that up to 15% of horseshoe crabs

研究显示，近 15% 的鲎

die in the process of having their blood harvested.

会在血液采集过程中死亡。

And recent research suggests this number may be even higher.

最新的研究发现， 这个数字可能更高。

Researchers have also observed fewer females returning to spawn

研究者发现在一些富产鲎的地区，

at some of the most harvested areas.

越来越少的雌鲎返回那里产卵。

Our impact on horseshoe crabs extends beyond the biomedical industry, too.

我们对鲎的影响甚至 超越了生物产业领域。

Coastal development destroys spawning sites,

近海开发破坏了产卵栖息地，

and horseshoe crabs are also killed for fishing bait.

鲎也时常死在鱼钩之下。

There's ample evidence that their populations are shrinking.

大量证据显示， 它们的数量正在急剧减少。

Some researchers have started working

一些研究者已经开始

to synthesize horseshoe crab blood in the lab.

在实验室合成鲎血。

For now, we're unlikely to stop our beach trips,

目前，我们还不可能停止捕获鲎，

but hopefully, a synthetic alternative will someday eliminate our reliance

但希望合成品有一天可以免除我们

on the blood of these ancient creatures.

对这些远古生物血液的依赖。