Cheryl Hayashi: The magnificence of spider silk

Translator: Cooper Ng Reviewer: Yipeng Xie

I'm here to spread the word about the

我喺度想講蜘蛛有幾勁

magnificence of spiders

and how much we can learn from them.

同埋我哋可以 從呢種動物身上學幾多嘢

Spiders are truly global citizens.

蜘蛛真係世界公民

You can find spiders in nearly

你差唔多可以 喺所有陸生生境上面揾到蜘蛛

every terrestrial habitat.

This red dot marks

呢個紅點就係北美洲大盤地

the Great Basin of North America,

喺嗰度，我同埋我班同事

and I'm involved with an alpine biodiversity

project there with some collaborators.

參與一個高山生物多樣性嘅研究

Here's one of our field sites,

呢個係我哋其中一個野外考察點

and just to give you a sense of perspective,

畀你睇下係點嘅樣

this little blue smudge here,

呢！呢個藍色點係我一個同事

that's one of my collaborators.

This is a rugged and barren landscape,

呢道雖然寸草不生

yet there are quite a few spiders here.

但係都有幾多蜘蛛㗎

Turning rocks over revealed this crab spider

翻轉嚿石頭

睇下呢隻蟹蛛同隻甲蟲玩雙撲

grappling with a beetle.

Spiders are not just everywhere,

蜘蛛唔單止周圍都係

而且仲好多種

but they're extremely diverse.

There are over 40,000 described species

有記錄嘅都超過四萬種

of spiders.

To put that number into perspective,

為咗明白個數字

here's a graph comparing the 40,000

呢幅圖比較四萬種蜘蛛 同四百種靈長類動物

species of spiders

to the 400 species of primates.

There are two orders of magnitude more

蜘蛛種類差唔多 係靈長類種類嘅百幾倍

spiders than primates.

Spiders are also extremely old.

蜘蛛算係好古老嘅生物

On the bottom here,

下面呢道，呢個係地質學嘅時標尺度

this is the geologic timescale,

and the numbers on it indicate millions

上面嘅數字代表幾百萬年前

of years from the present, so the zero here,

所以零就代表今日

that would be today.

So what this figure shows is that spiders

咁，呢個數字指出

蜘蛛可以追溯到 差唔多三億八千萬年前

date back to almost 380 million years.

To put that into perspective, this red

又咁講

vertical bar here marks the divergence time

呢條打直嘅紅色線

就係人類喺七百萬年前 從猿人分咗出嚟

of humans from chimpanzees,

a mere seven million years ago.

All spiders make silk

所有蜘蛛喺一生之中總會吐過絲

at some point in their life.

Most spiders use copious amounts of silk,

大部分蜘蛛會用上大量嘅絲

and silk is essential to their survival

而且，蜘蛛絲 對蜘蛛求生同繁殖都幾重要

and reproduction.

Even fossil spiders can make silk,

遠古嘅蜘蛛都可以做絲

as we can see from this impression of

因為我哋可以從石化咗嘅蜘蛛 身上嘅吐絲頭略知一二

a spinneret on this fossil spider.

所以，蜘蛛同埋蜘蛛絲

So this means that both spiders

and spider silk have been around

已經存在咗三億八千萬年

for 380 million years.

It doesn't take long from working with spiders

你唔使同蜘蛛相處太耐

to start noticing how essential silk is

就可以明白到蜘蛛絲 對蜘蛛一生有幾重要

to just about every aspect of their life.

Spiders use silk for many purposes, including

蜘蛛用絲有好多原因

例如搖曳安全拖絲

the trailing safety dragline,

wrapping eggs for reproduction,

包裹蜘蛛蛋以供繁殖

protective retreats

保護性撤退

同埋獵食

and catching prey.

There are many kinds of spider silk.

蜘蛛絲有好多種

For example, this garden spider can make

譬如，呢隻園蛛可以做 七種唔同嘅蜘蛛絲

seven different kinds of silks.

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

當你睇呢個環形蜘蛛網時

seeing many types of silk fibers.

你其實睇緊好多種蜘蛛絲纖維

The frame and radii of this web

網圈同網輻係由一種蜘蛛絲做

is made up of one type of silk,

但螺旋捕網卻係由兩種唔同嘅蜘蛛絲：

while the capture spiral is a composite

of two different silks:

the filament and the sticky droplet.

小絲體同埋粘滴組成

How does an individual spider

蜘蛛係點樣整到咁多種蜘蛛絲呢？

make so many kinds of silk?

要揾答案，你就要睇埋啲蜘蛛嘅吐絲頭

To answer that, you have to look a lot closer

at the spinneret region of a spider.

So silk comes out of the spinnerets, and for

蜘蛛絲從吐絲頭嗰度出嚟

those of us spider silk biologists, this is what

對於我哋蜘蛛絲生物學家嚟講

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

吐絲頭就係蜘蛛嘅「生意」來源 （笑聲）

We spend long days ...

我哋用咗好長日子……

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

嘻，唔好笑，我嘅生活係咁

(Laughter)

（笑聲）

We spend long days and nights

我哋日以繼夜盯實蜘蛛呢部分

staring at this part of the spider.

And this is what we see.

以下就係我睇到嘅嘢

You can see multiple fibers

好多纖維從吐絲頭嗰度出嚟

coming out of the spinnerets, because

each spinneret has many spigots on it.

再深入啲睇

每個吐絲頭上面有好多個咀

Each of these silk fibers exits from the spigot,

每款絲纖維喺唔同嘅咀度噴出嚟

and if you were to trace the fiber back

如果你從纖維追溯入返蜘蛛身體

into the spider, what you would find is that

你揾到嘅係

each spigot connects to its own individual

每一個咀連接住獨立嘅絲腺體

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

絲腺體好似一個裝住好多絲蛋白嘅囊

with a lot of silk proteins stuck inside.

如果你有機會解剖圓網蜘蛛

So if you ever have the opportunity to dissect

an orb-web-weaving spider,

and I hope you do,

我希望你有機會揾到 一個好靚、半透明嘅絲腺體

what you would find is a bounty

of beautiful, translucent silk glands.

Inside each spider, there are hundreds

每隻蜘蛛裡面，有幾百個絲腺體

of silk glands, sometimes thousands.

有時，甚至成千個

These can be grouped into seven categories.

呢啲絲腺體可以分為七類

They differ by size, shape,

佢哋大細、外形唔同

and sometimes even color.

有時顏色都唔同

In an orb-web-weaving spider,

喺圓網蜘蛛裡面

you can find seven types of silk glands,

你可以揾到七種絲腺體

and what I have depicted here in this picture,

即係我喺呢張圖描述咁

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

我哋從一點鐘位置開始睇

嗰啲係小管狀嘅絲腺體

there's tubuliform silk glands, which are used

負責製造卵囊體外絲

to make the outer silk of an egg sac.

There's the aggregate and flagelliform silk

呢啲係聚狀絲腺同埋鞭狀絲腺

glands which combine to make the sticky

聚狀絲腺同鞭狀絲腺一齊製造 圓網蜘蛛網上面好黐嘅螺旋捕網

capture spiral of an orb web.

Pyriform silk glands make the attachment

梨渦狀絲腺製造黐固劑

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

即係黐住蜘蛛絲同埋基質嘅嘢

silk lines to a substrate.

There's also aciniform silk,

葡萄串狀絲用嚟包住獵物

which is used to wrap prey.

Minor ampullate silk is used in web construction.

小壺腹狀絲用嚟起網

And the most studied silk line

研究得最多嘅絲：

of them all: major ampullate silk.

大壺腹狀絲

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

呢種絲用嚟做圈、輻，同搖曳安全拖絲

and radii of an orb web, and also

the safety trailing dragline.

咁蜘蛛絲究竟係點㗎呢？

But what, exactly, is spider silk?

Spider silk is almost entirely protein.

蜘蛛絲差唔多全部由蛋白質造成

Nearly all of these proteins can be explained

絕大部分呢啲蛋白質 都能夠由單基因家族解釋

by a single gene family,

so this means that the diversity of silk types

所以，我哋今日睇到不同種類嘅蜘蛛絲

we see today is encoded by one gene family,

都係由單基因家族所編碼而成

因此，可以假設 原始蜘蛛祖先只係做一種絲

so presumably the original spider ancestor

made one kind of silk,

and over the last 380 million years,

同埋喺過去嘅三億八千萬年

that one silk gene has duplicated

有一種蜘蛛絲基因複製咗

and then diverged, specialized,

跟着，分開演變、專門化

同一條基因不停不停咁重複以上

over and over and over again, to get

the large variety of flavors of spider silks

最後演化出大量唔同樣嘅蜘蛛絲

that we have today.

但所有呢啲蜘蛛絲都有幾個共同點

There are several features that all these silks

have in common. They all have a common

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

譬如佢哋都係好長

they're sort of outlandishly long

同其他蛋白質比較，佢哋長得出奇

compared to other proteins.

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

佢哋又高度重複

同埋擁有好多甘氨酸 同丙氨酸類型嘅氨基酸

in the amino acids glycine and alanine.

To give you an idea of what

為咗將一粒蜘蛛絲蛋白形象化

a spider silk protein looks like,

this is a dragline silk protein,

呢條係拖絲蛋白

it's just a portion of it,

正確啲嚟講

係黑寡婦蜘蛛吐出嚟嘅 拖絲蛋白嘅其中一部分

from the black widow spider.

This is the kind of sequence that I love

呢款蛋白序列，我好鐘意日日夜夜睇住

looking at day and night. (Laughter)

（笑聲）

So what you're seeing here is the one letter

你呢道睇到嘅字母係氨基酸嘅簡寫

abbreviation for amino acids, and I've colored

in the glycines with green,

我用綠色標示甘氨酸

and the alanines in red, and so

紅色標示丙氨酸

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

你會睇到好多 G 呀同 A 呀

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

同埋好多短又重複嘅序列

sequence motifs that repeat over and over

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

所以舉例嚟講

what we call polyalanines, or iterated A's,

有好多多聚丙氨酸 或者寫做 A，就係 AAAAA

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

亦都有 GGQ，同埋有 GGY

You can think of these short motifs

你想像呢啲短嘅序列組成詞語

that repeat over and over again as words,

and these words occur in sentences.

而詞言轉過嚟又組成句子

So for example this would be one sentence,

舉個例，呢道等如一句句子

and you would get this sort of green region

綠色呢部分同埋紅色呢部分嘅 多聚丙氨酸會不斷重複

and the red polyalanine, that repeats

over and over and over again,

and you can have that hundreds and

以至你會見到一條絲分子裡面 有幾何級數嘅氨基酸序列

hundreds and hundreds of times within

an individual silk molecule.

Silks made by the same spider can have

同一隻蜘蛛吐嘅絲 可以有好唔同嘅重複序列

dramatically different repeat sequences.

At the top of the screen, you're seeing

喺熒光幕頂上面

你見到園金蛛嘅拖絲嘅重複單位

the repeat unit from the dragline silk

of a garden argiope spider.

It's short. And on the bottom,

個重複單位好短

喺下面，呢個就係同一隻蜘蛛嘅

this is the repeat sequence for the

egg case, or tubuliform silk protein,

卵鞘或者小管狀絲蛋白嘅重複序列

for the exact same spider. And you can see

你可以見到呢啲絲蛋白有幾唔同

how dramatically different

these silk proteins are -- so this is

所以，呢個就係 蜘蛛絲基因家族多元化嘅美

sort of the beauty of the diversification

of the spider silk gene family.

重複單位唔單止每個長度不一

You can see that the repeat units differ

in length. They also differ in sequence.

佢哋嘅序列都唔同

So I've colored in the glycines again

而家，我再將甘氨酸填上綠色

in green, alanine in red, and the serines,

丙氨酸填紅色

絲氨酸，即係大楷 S，填紫色

the letter S, in purple. And you can see

that the top repeat unit can be explained

咁樣，你能夠見到

上面嗰啲重複單位 差唔多都係綠色、紅色

almost entirely by green and red,

and the bottom repeat unit has

同埋下面嘅重複單位好多都係紫色

a substantial amount of purple.

What silk biologists do is we try to relate

我哋生物學家嘗試用

these sequences, these amino acid

呢啲序列、呢啲氨基酸序列

sequences, to the mechanical properties

去解釋絲纖維嘅機械特性

of the silk fibers.

蜘蛛將佢哋啲絲全部用喺身體出面 對我哋嚟講真係好方便

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

completely outside their body.

This makes testing spider silk really, really

因為咁樣令測試蜘蛛絲超簡單

easy to do in the laboratory, because

要知道，我哋喺實驗室度 係喺空氣之中測試蜘蛛絲嘅

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

that's exactly the environment that

務求同實際蜘蛛 用佢哋嘅絲蛋白環境一模一樣

spiders are using their silk proteins.

So this makes quantifying silk properties by

量度蜘蛛絲特性嘅定量方法 包括有延展測試

methods such as tensile testing, which is

basically, you know, tugging on one end

亦即係拉痕纖維兩端，令佢好貼服咁

of the fiber, very amenable.

Here are stress-strain curves

呢個應力應變曲線

generated by tensile testing

由測試同一隻蜘蛛製造嘅 五條纖維所產生

five fibers made by the same spider.

So what you can see here is that

喺度，你見到五種纖維有唔同特性

the five fibers have different behaviors.

Specifically, if you look on the vertical axis,

你睇下條縱軸嗰個應力

that's stress. If you look at the maximum

如果你睇呢啲纖維嘅最大應力值

stress value for each of these fibers,

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

你就睇到真係好多變化

and in fact dragline, or major ampullate silk,

事實上，拖絲或者壺腹狀絲 係呢啲纖維裡面最強嘅

is the strongest of these fibers.

We think that's because the dragline silk,

我哋諗，因為拖絲 係用嚟做蜘蛛網嘅圈同輻

which is used to make the frame and radii

所以要好強

for a web, needs to be very strong.

On the other hand, if you were to look at

但如果你睇張力

strain -- this is how much a fiber can be

即係纖維可以拉幾長

extended -- if you look at the maximum value

如果你睇著個最大數值

here, again, there's a lot of variation

呢道，又係好多變化

and the clear winner is flagelliform,

好明顯，係鞭毛狀絲或者捕旋小絲勝出

or the capture spiral filament.

In fact, this flagelliform fiber can

實際上，鞭毛狀纖維 可以真係拉長超過一倍

actually stretch over twice its original length.

So silk fibers vary in their strength

所以絲纖維有唔同嘅強度 同埋唔同嘅伸展能力

and also their extensibility.

In the case of the capture spiral,

至於螺旋捕網

it needs to be so stretchy to absorb

佢要夠延伸力 去吸收飛行獵物嘅衝擊

the impact of flying prey.

如果佢唔能夠延伸好多

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

咁當昆蟲撞埋蜘蛛網嗰陣

basically when an insect hit the web,

就會彈翻出去

it would just trampoline right off of it.

所以如果成個蜘蛛網都係用拖絲所做

So if the web was made entirely out of

dragline silk, an insect is very likely to just

昆蟲只會成日彈入又彈出

bounce right off. But by having really, really

但係，如果真係用 超級伸展嘅捕蟲螺旋絲

stretchy capture spiral silk, the web is actually

able to absorb the impact

個網就有能力吸收衝擊、捕著獵物

of that intercepted prey.

There's quite a bit of variation within

由於蜘蛛造嘅纖維當中有唔細嘅變化

the fibers that an individual spider can make.

We call that the tool kit of a spider.

所以我哋戲稱蜘蛛個肚為「工具箱」

That's what the spider has

令佢哋有足夠款式嘅纖維同環境互動

to interact with their environment.

但係，蜘蛛種類之間嘅差異係點嘅呢？

But how about variation among spider

species, so looking at one type of silk

不如睇下唔同蜘蛛但同一種嘅絲？

and looking at different species of spiders?

This is an area that's largely unexplored

呢個領域大部分地方都未探討過

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

但係，我呢道有啲數據可以畀你睇

This is the comparison of the toughness

呢道比較 21 種蜘蛛所吐嘅拖絲

of the dragline spilk spun

by 21 species of spiders.

Some of them are orb-weaving spiders and

有啲係圓網蜘蛛

some of them are non-orb-weaving spiders.

有啲唔係圓網蜘蛛

It's been hypothesized that

有人曾經假設過

orb-weaving spiders, like this argiope here,

圓網蜘蛛好似金蛛咁擁有最韌嘅拖絲

should have the toughest dragline silks

because they must intercept flying prey.

因為佢哋一定要捕捉飛行獵物

What you see here on this toughness graph

呢道你睇緊嘅韌度圖

is the higher the black dot is on the graph,

圖上面黑點越高，代表越韌

the higher the toughness.

The 21 species are indicated here by this

呢道幅進化樹圖係說明 21 種蜘蛛基因關係

phylogeny, this evolutionary tree, that shows

their genetic relationships, and I've colored

in yellow the orb-web-weaving spiders.

我填咗圓網蜘蛛黃色

If you look right here at the two red arrows,

而兩個紅箭咀就指向 新婦蛛同埋十字園蛛嘅韌度值

they point to the toughness values

for the draglines of nephila clavipes and

araneus diadematus.

These are the two species of spiders

講開新婦蛛同埋十字園蛛

合成蜘蛛絲嘅研究嘅大部分時間同金錢

for which the vast majority of time and money

on synthetic spider silk research has been

都用喺複製呢兩種蜘蛛嘅拖絲蛋白

to replicate their dragline silk proteins.

Yet, their draglines are not the toughest.

但係，佢哋嘅拖絲唔係最韌嘅

In fact, the toughest dragline in this survey

事實上，呢個調查發現最韌嘅拖絲

is this one right here in this white region,

係白色呢部分，一種圓網蜘蛛造嘅拖絲

a non orb-web-weaving spider.

This is the dragline spun by scytodes,

呢條拖線由花皮蛛所吐

the spitting spider.

Scytodes doesn't use a web at all

花皮蛛根本唔用網嚟捕獵

to catch prey. Instead, scytodes

而係潜伏一旁

sort of lurks around and waits for prey

等待獵物慢慢走近自己

to get close to it, and then immobilizes prey

然後噴啲好似絲嘅毒液落昆蟲度

by spraying a silk-like venom onto that insect.

令獵物唔郁得

Think of hunting with silly string.

花皮蜘蛛就係用絲線捕獵

That's how scytodes forages.

We don't really know why scytodes

我哋唔知點解花皮蛛需要咁韌嘅拖絲

needs such a tough dragline,

but it's unexpected results like this that make

但就係好似呢啲不尋常發現

bio-prospecting so exciting and worthwhile.

令生物勘探咁刺激同有價值

It frees us from the constraints

不尋常發現幫我哋衝破想像嘅限制

of our imagination.

Now I'm going to mark on

而家，我準備標上

the toughness values for nylon fiber,

尼龍纖維、蠶蟲絲 羊毛、克維拉

bombyx -- or domesticated silkworm silk --

wool, Kevlar, and carbon fibers.

同埋炭纖維嘅韌值

And what you can see is that nearly

你可以見到

差唔多所有蜘蛛嘅拖絲都比以上物料韌

all the spider draglines surpass them.

It's the combination of strength, extensibility

蜘蛛絲之所以咁特別

同吸引仿生學家注意

and toughness that makes spider silk so

係因為佢柔合強度、伸展度，同埋韌度

special, and that has attracted the attention

of biomimeticists, so people that turn

亦因為咁，人類轉向 從大自然尋找解决方法

to nature to try to find new solutions.

And the strength, extensibility and toughness

蜘蛛絲嘅強度、伸展度，同埋韌度

of spider silks combined with the fact that

加上蜘蛛絲唔會引致免疫反應嘅特點

silks do not elicit an immune response,

have attracted a lot of interest in the use

令到蜘蛛絲應用喺生物醫學上相當吸引

of spider silks in biomedical applications,

for example, as a component of

例如，作為人造肌腱嘅物料

artificial tendons, for serving as

用於引導神經再生

guides to regrow nerves, and for

同作為組織生長嘅支架

scaffolds for tissue growth.

Spider silks also have a lot of potential

蜘蛛絲嘅防彈特性亦都非常有應用潛力

for their anti-ballistic capabilities.

Silks could be incorporated into body

蜘蛛絲可以用於盔甲同裝備保護上

and equipment armor that would be more

令佢哋更輕、更柔韌

lightweight and flexible

than any armor available today.

In addition to these biomimetic

蜘蛛絲除咗有仿生學應用價值之外

applications of spider silks,

personally, I find studying spider silks

蜘蛛絲仲會令人陶醉

just fascinating in and of itself.

I love when I'm in the laboratory,

我好鍾意當我喺實驗室嗰時

a new spider silk sequence comes in.

有一條新嘅蜘蛛絲序列送入嚟

That's just the best. (Laughter)

呢樣嘢係最正嘅 （笑聲）

It's like the spiders are sharing

我覺得，蜘蛛好似 同我分享緊一個遠古秘密

an ancient secret with me, and that's why

I'm going to spend the rest of my life

所以我會用我嘅餘生研究蜘蛛絲

studying spider silk.

The next time you see a spider web,

下次，當你見到蜘蛛網時

唔該，停一停

please, pause and look a little closer.

睇埋啲一種人類已知最高性能嘅材料

You'll be seeing one of the most

high-performance materials known to man.

To borrow from the writings

借用文學嘅一句話

of a spider named Charlotte,

一隻叫夏洛特嘅蜘蛛話︰

「蜘蛛絲係偉大嘅。」

silk is terrific.

多謝 （鼓掌）

Thank you. (Applause)

（鼓掌）

(Applause)