Cheryl Hayashi: The magnificence of spider silk

翻译人员: Ying Ding 校对人员: Stephanie Zhou

I'm here to spread the word about the

我来到这里是为了向让世人了解

magnificence of spiders

蜘蛛的伟大之处

and how much we can learn from them.

以及我们能从它们身上学到多少东西

Spiders are truly global citizens.

蜘蛛遍布全球，这点勿庸置疑

You can find spiders in nearly

你几乎能在每一个

every terrestrial habitat.

陆地栖息地中找到蜘蛛

This red dot marks

这个红点标出了

the Great Basin of North America,

北美大盆地地区

and I'm involved with an alpine biodiversity

我和一些人合作

project there with some collaborators.

参与了一个山地生物多样性的项目

Here's one of our field sites,

这里是我们的野外场地之一

and just to give you a sense of perspective,

你可以看到

this little blue smudge here,

这里有个小蓝点

that's one of my collaborators.

那是我的合作者之一

This is a rugged and barren landscape,

这里虽地势崎岖，土地贫瘠

yet there are quite a few spiders here.

但存在相当数量的蜘蛛

Turning rocks over revealed this crab spider

翻开岩石就可以看见一只蟹蛛

grappling with a beetle.

正与一只甲壳虫搏斗

Spiders are not just everywhere,

蜘蛛并非随处可见

but they're extremely diverse.

但它们品种繁多

There are over 40,000 described species

目前已有超过40000种

of spiders.

蜘蛛

To put that number into perspective,

根据这个数字

here's a graph comparing the 40,000

这里有一张图表用以比较

species of spiders

蜘蛛的40000个品种和

to the 400 species of primates.

灵长类动物的400个品种

There are two orders of magnitude more

蜘蛛的种类比灵长类动物

spiders than primates.

多了两个数量级

Spiders are also extremely old.

蜘蛛也极其古老

On the bottom here,

在图表的底部

this is the geologic timescale,

是一个地质年代表

and the numbers on it indicate millions

表上的数字所指的是

of years from the present, so the zero here,

距今数百万年以前，而这里的数字零

that would be today.

代表今天

So what this figure shows is that spiders

所以该图表显示，蜘蛛的出现

date back to almost 380 million years.

可追溯至约3.8亿年前

To put that into perspective, this red

相比较而言

vertical bar here marks the divergence time

这条红色垂直轴标记着

of humans from chimpanzees,

猩猩演化成人类的时间

a mere seven million years ago.

那也不过只有七百万年

All spiders make silk

在其生命中的某些时间点上

at some point in their life.

所有的蜘蛛都会吐丝

Most spiders use copious amounts of silk,

大多数蜘蛛会用到大量的蛛丝

and silk is essential to their survival

且蛛丝对于蜘蛛的存活

and reproduction.

和繁殖也至关重要

Even fossil spiders can make silk,

即使是远古的蜘蛛也能够吐丝

as we can see from this impression of

我们在图上可以看到

a spinneret on this fossil spider.

这只古老的蜘蛛的吐丝器

So this means that both spiders

这就意味着

and spider silk have been around

蜘蛛和蛛丝都已经

for 380 million years.

存活了3.8亿年了

It doesn't take long from working with spiders

研究蜘蛛，你不用花很长时间

to start noticing how essential silk is

就会开始注意到蛛丝对于

to just about every aspect of their life.

蜘蛛生存的每个方面都十分重要

Spiders use silk for many purposes, including

蜘蛛使用蛛丝有多种目的

the trailing safety dragline,

包括用拖丝确保其安全

wrapping eggs for reproduction,

包缠它们的蛋以利于繁殖

protective retreats

撤退时的保护机制

and catching prey.

以及捕获猎物

There are many kinds of spider silk.

蛛丝种类繁多

For example, this garden spider can make

举例来说，这种园蛛能够

seven different kinds of silks.

吐出七种不同的蛛丝

When you look at this orb web, you're actually

当你看到这种圆形蛛网

seeing many types of silk fibers.

事实上，你看到了多种蛛丝纤维

The frame and radii of this web

蛛网的骨架丝与辐射状丝

is made up of one type of silk,

是由同一种蛛丝织成

while the capture spiral is a composite

而螺旋状的蛛丝部分是由

of two different silks:

两种不同的丝组成

the filament and the sticky droplet.

即单纤维细丝和小滴的粘液

How does an individual spider

那么一只蜘蛛是如何

make so many kinds of silk?

吐出这么多不同的蛛丝的呢？

To answer that, you have to look a lot closer

想知道答案，你必须更加贴近观察

at the spinneret region of a spider.

蜘蛛的吐丝器部位

So silk comes out of the spinnerets, and for

蛛丝源于吐丝器

those of us spider silk biologists, this is what

对于那些像我一样的蛛丝生物学家来说

we call the "business end" of the spider. (Laughter)

这就是所谓的蜘蛛的“业务端点”

We spend long days ...

我们花了很长时间...

Hey! Don't laugh. That's my life.

嘿！别笑！那可是我的人生！

(Laughter)

（笑声）

We spend long days and nights

我们整日整夜的

staring at this part of the spider.

瞪着蜘蛛的吐丝器

And this is what we see.

然后我们观察到了这个

You can see multiple fibers

你可以看到吐丝器里

coming out of the spinnerets, because

吐出了多种纤维

each spinneret has many spigots on it.

因为每个吐丝器都有许多栓塞

Each of these silk fibers exits from the spigot,

而每一条蛛丝纤维都来自于栓塞

and if you were to trace the fiber back

如果循着纤维追溯到蜘蛛本体当中

into the spider, what you would find is that

你就会发现

each spigot connects to its own individual

每个栓塞都各自连结了一个独立丝腺

silk gland. A silk gland kind of looks like a sac

丝腺看起来就像是一个小囊

with a lot of silk proteins stuck inside.

囊中充满了蛛丝蛋白

So if you ever have the opportunity to dissect

所以如果你曾经有机会解剖

an orb-web-weaving spider,

一只圆蛛

and I hope you do,

我也希望你有机会这么做

what you would find is a bounty

你就会发现

of beautiful, translucent silk glands.

它有大量漂亮且半透明的丝腺

Inside each spider, there are hundreds

每只蜘蛛体内都有数百种丝腺

of silk glands, sometimes thousands.

有时候高达数千种

These can be grouped into seven categories.

这些丝腺可以被分为7类

They differ by size, shape,

它们大小不一，形状各异

and sometimes even color.

有时甚至连颜色也不同

In an orb-web-weaving spider,

在一只圆蛛体内

you can find seven types of silk glands,

你能找到七种不同的丝腺

and what I have depicted here in this picture,

而我在这张图中已把它们一一描绘出来

let's start at the one o'clock position,

我们从一点的位置开始

there's tubuliform silk glands, which are used

这里是管状丝腺

to make the outer silk of an egg sac.

用于制作卵囊的外部

There's the aggregate and flagelliform silk

这里是聚状丝腺和鞭状丝腺

glands which combine to make the sticky

它们均用于制造蛛网上

capture spiral of an orb web.

富有黏性的螺旋状丝

Pyriform silk glands make the attachment

梨状丝腺具有黏合作用

cement -- that's the silk that's used to adhere

这种蛛丝用于将丝线

silk lines to a substrate.

黏合在蛛网的基底上

There's also aciniform silk,

还有葡萄状腺丝

which is used to wrap prey.

用于捕获猎物

Minor ampullate silk is used in web construction.

小壶状腺丝则用于建构蛛网

And the most studied silk line

而在这些蛛丝中

of them all: major ampullate silk.

最常被研究的是大壶状腺丝

This is the silk that's used to make the frame

大壶状腺丝用于制造

and radii of an orb web, and also

蛛网的骨架丝和辐射状丝

the safety trailing dragline.

以及用于安全警戒的拖丝

But what, exactly, is spider silk?

但准确的说，蛛丝究竟是什么？

Spider silk is almost entirely protein.

蛛丝几乎全由蛋白质组成

Nearly all of these proteins can be explained

其中大多数蛋白质可以用

by a single gene family,

单基因家族解释

so this means that the diversity of silk types

这就表示我们今日所见的蜘蛛丝分类

we see today is encoded by one gene family,

都是由单基因家族编码

so presumably the original spider ancestor

所以，我们可以推测，最远古的蜘蛛始祖

made one kind of silk,

可能只能吐出一种丝

and over the last 380 million years,

后来经过3.8亿年的演化

that one silk gene has duplicated

其蛛丝基因被复制

and then diverged, specialized,

接着出现分歧化和专门化

over and over and over again, to get

这样的过程不断重复

the large variety of flavors of spider silks

最终演化成我们今天的

that we have today.

各种各样的蛛丝

There are several features that all these silks

这些蛛丝有几个共通点

have in common. They all have a common

他们的设计都大同小异

design, such as they're all very long --

例如都非常的长

they're sort of outlandishly long

跟其它的丝质蛋白相比

compared to other proteins.

蛛丝蛋白长得有点古怪

They're very repetitive, and they're very rich

它们颇具重复性且内含丰富的

in the amino acids glycine and alanine.

氨基酸，甘氨酸和丙氨酸

To give you an idea of what

为了让你能够想像

a spider silk protein looks like,

蛛丝蛋白的样子

this is a dragline silk protein,

这是拖丝蛋白

it's just a portion of it,

这只是它的一部分

from the black widow spider.

是从黑寡妇体内取出来的

This is the kind of sequence that I love

这种序列

looking at day and night. (Laughter)

我每日每夜百看不厌

So what you're seeing here is the one letter

所以你可以在这里看到

abbreviation for amino acids, and I've colored

氨基酸仅用一个字母的缩写表示

in the glycines with green,

并且我用绿色标明氨基酸

and the alanines in red, and so

用红色标明丙氨酸

you can see it's just a lot of G's and A's.

所以你们看见了很多G's和A's

You can also see that there's a lot of short

你也可以看到有很多短序列基元

sequence motifs that repeat over and over

被不断重复

and over again, so for example there's a lot of

比如说这里有大量的多聚丙氨酸

what we call polyalanines, or iterated A's,

也就是不停重复的A's

AAAAA. There's GGQ. There's GGY.

AAAAA。这里是GGQ，这里是GGY

You can think of these short motifs

你可以将这些不断重复的短序列

that repeat over and over again as words,

想像成单词

and these words occur in sentences.

而这些单词会出现在句子中

So for example this would be one sentence,

所以，举例来说，这是一个句子

and you would get this sort of green region

你会得到这种绿色区块

and the red polyalanine, that repeats

和红色多聚丙氨酸的组合

over and over and over again,

这种组合会一再重复

and you can have that hundreds and

然后你就会在一个蛛丝分子中

hundreds and hundreds of times within

得到数百个不断重复的

an individual silk molecule.

上述组合

Silks made by the same spider can have

相同的蜘蛛吐出的丝

dramatically different repeat sequences.

可以有截然不同的重复序列

At the top of the screen, you're seeing

在萤幕的上方，你看到的是

the repeat unit from the dragline silk

一只花园金蛛的

of a garden argiope spider.

拖丝重复序列单位

It's short. And on the bottom,

它非常的短，而在底部

this is the repeat sequence for the

是蛋壳的重复序列

egg case, or tubuliform silk protein,

即管状腺丝蛋白的序列

for the exact same spider. And you can see

它们来自同一只蜘蛛

how dramatically different

这样你就可以看到

these silk proteins are -- so this is

这些蛛丝蛋白有多么迥异

sort of the beauty of the diversification

这就是蛛丝基因家族多样化的

of the spider silk gene family.

美妙之处

You can see that the repeat units differ

你可以看到重复单位长度各异

in length. They also differ in sequence.

它们的序列方式也大相径庭

So I've colored in the glycines again

所以我再次用绿色标出甘氨酸

in green, alanine in red, and the serines,

用红色标出丙氨酸

the letter S, in purple. And you can see

紫色的字母S代表丝氨酸

that the top repeat unit can be explained

你可以看到顶部的重复单位

almost entirely by green and red,

几乎全部可用绿色和红色显示

and the bottom repeat unit has

而下方的重复单位

a substantial amount of purple.

则有很大一部分是紫色的

What silk biologists do is we try to relate

研究蛛丝的生物学家要做的就是试着

these sequences, these amino acid

将这些氨基酸序列

sequences, to the mechanical properties

与蛛丝纤维的机械属性

of the silk fibers.

加以连结

Now, it's really convenient that spiders use their silk

现在，因为蜘蛛将丝吐出身体之外

completely outside their body.

所以我们的研究变得很便利

This makes testing spider silk really, really

这就让在实验室做蛛丝测试

easy to do in the laboratory, because

变得非常简易，因为事实上

we're actually, you know, testing it in air

你也知道，我们可以直接在空气中测试

that's exactly the environment that

因为蜘蛛恰恰是在那样的环境中

spiders are using their silk proteins.

使用蛛丝蛋白的

So this makes quantifying silk properties by

因此这就让量化蛛丝属性变得非常容易执行

methods such as tensile testing, which is

比如基本的拉伸试验

basically, you know, tugging on one end

即拉住纤维的某一端

of the fiber, very amenable.

会变得非常方便

Here are stress-strain curves

这是同一只蜘蛛产岀的五种纤维

generated by tensile testing

进行拉伸试验后

five fibers made by the same spider.

所产生的应变曲线

So what you can see here is that

你可以看到

the five fibers have different behaviors.

五种纤维各有不同的反应

Specifically, if you look on the vertical axis,

具体来说，垂直轴代表压力

that's stress. If you look at the maximum

如果你注意每一种纤维的

stress value for each of these fibers,

最大压力值

you can see that there's a lot of variation,

那么你就可以看出变异实在太多了

and in fact dragline, or major ampullate silk,

而事实上，拖丝或大壶状腺丝

is the strongest of these fibers.

是这些纤维里最强韧的

We think that's because the dragline silk,

我们认为这是因为拖丝

which is used to make the frame and radii

用于制造蛛网的骨架丝和辐射状丝

for a web, needs to be very strong.

所以需要比其他蛛丝更加强韧

On the other hand, if you were to look at

另外，如果你注意到张力

strain -- this is how much a fiber can be

即一条纤维可被延展的程度

extended -- if you look at the maximum value

如果你注意到它的最大值

here, again, there's a lot of variation

那么，你会再次发现有很多变异

and the clear winner is flagelliform,

而延展性最好的是鞭毛状的蛛丝

or the capture spiral filament.

即用于捕猎的螺旋状丝纤维

In fact, this flagelliform fiber can

事实上，鞭毛状丝纤维可以

actually stretch over twice its original length.

延展至超过其原本长度的两倍

So silk fibers vary in their strength

所以在长度和延展性上

and also their extensibility.

蛛丝纤维是各不相同的

In the case of the capture spiral,

以螺旋状丝为例

it needs to be so stretchy to absorb

它必须非常有弹性

the impact of flying prey.

才能经受住飞行猎物的冲撞

If it wasn't able to stretch so much, then

如果它延展性不够

basically when an insect hit the web,

那么基本上，当有昆虫落入蛛网时

it would just trampoline right off of it.

这些昆虫就能从蛛网上弹开

So if the web was made entirely out of

所以如果蛛网全部用拖丝做成

dragline silk, an insect is very likely to just

那么昆虫很可能只是

bounce right off. But by having really, really

从网上弹开，但是由于有

stretchy capture spiral silk, the web is actually

可延展性极佳的的螺旋状丝

able to absorb the impact

蛛网就能经受住

of that intercepted prey.

被拦截的昆虫的冲撞力

There's quite a bit of variation within

在一只蜘蛛可以吐出的纤维中

the fibers that an individual spider can make.

存在很多的差异

We call that the tool kit of a spider.

我们称之为蜘蛛的工具箱

That's what the spider has

那就是蜘蛛与环境之间

to interact with their environment.

进行互动所必需的

But how about variation among spider

但是不同的蜘蛛之间存在多大的差异呢?

species, so looking at one type of silk

是以同一种蛛丝为基础

and looking at different species of spiders?

还是用不同的蜘蛛种类來作区分？

This is an area that's largely unexplored

这是一片尚未探知的领域

but here's a little bit of data I can show you.

但我还是能提供一些数据給各位

This is the comparison of the toughness

这是拖丝的韧性比较

of the dragline spilk spun

这些拖丝

by 21 species of spiders.

取自21种蜘蛛

Some of them are orb-weaving spiders and

有些是圆网蜘蛛

some of them are non-orb-weaving spiders.

有些是非圆网蜘蛛

It's been hypothesized that

有人假设圆网蜘蛛

orb-weaving spiders, like this argiope here,

例如这里的金蛛

should have the toughest dragline silks

这类蜘蛛的拖丝应该是最具韧性的

because they must intercept flying prey.

因为它们必须截获飞行的猎物

What you see here on this toughness graph

从韧性图表上看

is the higher the black dot is on the graph,

黑点在图上的位置越高

the higher the toughness.

其代表的韧性就越大

The 21 species are indicated here by this

这21种蜘蛛通过这个系统演化

phylogeny, this evolutionary tree, that shows

被标识出来。这个演化树指出了

their genetic relationships, and I've colored

它们的基因关系，我用黃色

in yellow the orb-web-weaving spiders.

标出了圆网蜘蛛

If you look right here at the two red arrows,

这里有两个红色箭头

they point to the toughness values

它们显示出络新妇蛛

for the draglines of nephila clavipes and

和十字圆蛛的拖丝

araneus diadematus.

最具韧性

These are the two species of spiders

对于这两种蜘蛛

for which the vast majority of time and money

人们使用了大量的时间和金钱

on synthetic spider silk research has been

进行人造蛛丝的研究

to replicate their dragline silk proteins.

以复制它们的拖丝蛋白

Yet, their draglines are not the toughest.

然而，它们的拖丝并非最强韧的

In fact, the toughest dragline in this survey

事实上，根据这个调查，最强韧的拖丝

is this one right here in this white region,

是白色区域中的这个点

a non orb-web-weaving spider.

它属于一只非圆网蜘蛛

This is the dragline spun by scytodes,

这是由花皮蛛吐出的拖丝

the spitting spider.

花皮蛛是毒蜘蛛

Scytodes doesn't use a web at all

它们根本不结网捕猎

to catch prey. Instead, scytodes

相反，花皮蛛埋伏在四周

sort of lurks around and waits for prey

等待猎物临近

to get close to it, and then immobilizes prey

然后通过喷出丝状的毒液

by spraying a silk-like venom onto that insect.

来让猎物动弹不得

Think of hunting with silly string.

相较于用愚蠢的丝线来捕猎

That's how scytodes forages.

这才是花皮蛛的捕猎方式

We don't really know why scytodes

我们并不知道为什么花皮蛛

needs such a tough dragline,

需要如此强韧的拖丝

but it's unexpected results like this that make

但正是这类出乎意料的结果

bio-prospecting so exciting and worthwhile.

才让生物勘探如此的激动人心和富有价值

It frees us from the constraints

它将我们从想象力的束缚中

of our imagination.

解放出来

Now I'm going to mark on

现在我将标出

the toughness values for nylon fiber,

以下物质的韧性值，包括尼龙纤维

bombyx -- or domesticated silkworm silk --

家蚕丝

wool, Kevlar, and carbon fibers.

羊毛，凯夫拉纤维和碳质纤维

And what you can see is that nearly

你可以看到几乎

all the spider draglines surpass them.

所有蜘蛛拖丝的韧性都能超越它们

It's the combination of strength, extensibility

正是结合了强力，延展性和韧性

and toughness that makes spider silk so

才让蛛丝如此的特别

special, and that has attracted the attention

它亦引起了仿生学家的注意

of biomimeticists, so people that turn

所以人们转向大自然

to nature to try to find new solutions.

以求发现新的解决方案

And the strength, extensibility and toughness

而蛛丝集强力，延展性

of spider silks combined with the fact that

和韧性于一体

silks do not elicit an immune response,

却并不会引发免疫应答

have attracted a lot of interest in the use

这一事实引起了人们将蛛丝应用于

of spider silks in biomedical applications,

生物医学领域的兴趣

for example, as a component of

比如说作为人造腱的成分

artificial tendons, for serving as

用以帮助神经再生

guides to regrow nerves, and for

作为脚手架

scaffolds for tissue growth.

帮助组织生长

Spider silks also have a lot of potential

蛛丝也因其反弹道能力

for their anti-ballistic capabilities.

而拥有很多潜能

Silks could be incorporated into body

蛛丝可被植入体内

and equipment armor that would be more

以及装备装甲当中，以让其变得更加

lightweight and flexible

轻便灵活

than any armor available today.

远胜于今天的任何装甲

In addition to these biomimetic

除了蛛丝在

applications of spider silks,

仿生学上的应用

personally, I find studying spider silks

就我个人而言，我发现研究蛛丝

just fascinating in and of itself.

非常的令人着迷

I love when I'm in the laboratory,

我很喜欢待在实验室

a new spider silk sequence comes in.

研究新的蛛丝序列

That's just the best. (Laughter)

那真是再好不过了

It's like the spiders are sharing

就像蜘蛛正在与我

an ancient secret with me, and that's why

分享一个远古的秘密

I'm going to spend the rest of my life

那也是为什么我将倾尽余生

studying spider silk.

来研究蛛丝

The next time you see a spider web,

下次当你看到一个蛛网时

please, pause and look a little closer.

请停下来并走近观察

You'll be seeing one of the most

你将会看到人类已知的

high-performance materials known to man.

性能最佳的材料之一

To borrow from the writings

借用一只名叫

of a spider named Charlotte,

夏洛特的蜘蛛的话来说

silk is terrific.

蛛丝棒极了

Thank you. (Applause)

谢谢

(Applause)

（掌声）