Martin Hanczyc: The line between life and not-life

翻译人员: Chunxiang Qian 校对人员: Angelia King

So historically there has

有史以来

been a huge divide between what people

人们所认识的

consider to be non-living systems on one

生命体和非生命体之间

side, and living systems on the other side.

是有巨大差异的

So we go from, say, this beautiful and

比如说

complex crystal as non-life, and this rather

这个美丽而复杂的晶体

beautiful and complex cat on the other side.

和这个可爱而复杂的小猫之间的差异

Over the last hundred and fifty years or so,

在过去约一百五十年间

science has kind of blurred this distinction

科学发现对

between non-living and living systems, and

生命和非生命的界线逐渐模糊

now we consider that there may be a kind

现在我们认为二者之间存在

of continuum that exists between the two.

连续性物质

We'll just take one example here:

举个例子：

a virus is a natural system, right?

病毒是个自然系统，是吧？

But it's very simple. It's very simplistic.

但它非常简单

It doesn't really satisfy all the requirements,

它并不满足生命的所有条件

it doesn't have all the characteristics

它不具备一个生命系统的

of living systems and is in fact a parasite

所有特征，而是一个

on other living systems in order to, say,

寄生于另一生命体

reproduce and evolve.

来繁殖和进化

But what we're going to be talking about here

但是今晚我将谈到的

tonight are experiments done on this sort of

是更接近非生命这一端的

non-living end of this spectrum -- so actually

实验

doing chemical experiments in the laboratory,

通过实验室内的化学实验

mixing together nonliving ingredients

将非生命的物质混合

to make new structures, and that these

创造出新结构

new structures might have some of the

这些新结构就很可能

characteristics of living systems.

具有生命的一些特征

Really what I'm talking about here is

我要说的就是

trying to create a kind of artificial life.

创造人造生命

So what are these characteristics that I'm

那这些特征都是什么？

talking about? These are them.

我们来看

We consider first that life has a body.

首先是具备形体

Now this is necessary to distinguish the self

这是将自身与环境区别开的

from the environment.

必要条件

Life also has a metabolism. Now this is a

生命同时会新陈代谢

process by which life can convert resources

这是生命将从环境中获得的资源

from the environment into building blocks

转化为维持和发展自身的

so it can maintain and build itself.

基本构件的一个过程

Life also has a kind of inheritable information.

生命还要遗传信息

Now we, as humans, we store our information

比如人类将信息

as DNA in our genomes and we pass this

储存于基因中的DNA

information on to our offspring.

将其遗传给后代

If we couple the first two -- the body and the metabolism --

二者结合－形体和新陈代谢－

we can come up with a system that could

就能得到一个

perhaps move and replicate, and if we

可以运动和复制的系统

coupled these now to inheritable information,

如果结合信息遗传

we can come up with a system that would be

这个系统就更像生命

more lifelike, and would perhaps evolve.

也许可以进化

And so these are the things we will try to do

这些就是我们在实验室的研究

in the lab, make some experiments that have

通过一些实验来创造

one or more of these characteristics of life.

这其中一个或更多的生命特征

So how do we do this? Well, we use

我们是怎么做的呢？

a model system that we term a protocell.

我们首先用一个模型系统来定义原始细胞

You might think of this as kind of like a

你也许觉得这会是种

primitive cell. It is a simple chemical

原始形态的细胞

model of a living cell, and if you consider

它是一个活细胞的简单化学模型

for example a cell in your body may have

比如说你体内的一个细胞

on the order of millions of different types

由成千上万个不同的分子

of molecules that need to come together,

组成起来

play together in a complex network

成为一个复杂系统

to produce something that we call alive.

来生成我们赖以生存的东西

In the laboratory what we want to do

我们在实验室里进行的实验

is much the same, but with on the order of

基本就是此类工作

tens of different types of molecules --

但只有几十个不同的分子－

so a drastic reduction in complexity, but still

复杂度大大降低

trying to produce something that looks lifelike.

但是仍然能产生类似生命的物质

And so what we do is, we start simple

我们开始的工作很简单

and we work our way up to living systems.

然后一步一步向生命体迈进

Consider for a moment this quote by

试想一下

Leduc, a hundred years ago, considering a

勒杜克在一百年前说的话

kind of synthetic biology:

是关于合成生物学的

"The synthesis of life, should it ever occur,

“合成生命一旦出现

will not be the sensational discovery which we

将不会像我们以为的那样

usually associate with the idea."

耸人听闻”

That's his first statement. So if we actually

这是第一

create life in the laboratories, it's

如果我们真的在实验室创造出生命

probably not going to impact our lives at all.

可能对我们的生活没有任何影响

"If we accept the theory of evolution, then

“如果我们认可进化论

the first dawn of synthesis of life must consist

那么合成生命的出现必然不外乎

in the production of forms intermediate

无机和有机世界之间

between the inorganic and the organic

产生的形态

world, or between the non-living

或者是非生命

and living world, forms which possess

和生命世界之间的

only some of the rudimentary attributes of life"

只具备基本生命要素的物质形态”

-- so, the ones I just discussed --

那么我刚刚提到的一点

"to which other attributes will be slowly added

“其他的要素

in the course of development by the

在环境的演化进程中

evolutionary actions of the environment."

慢慢加入”

So we start simple, we make some structures

所以从简单入手 首先我创造了

that may have some of these characteristics

具备几个基本特征的结构

of life, and then we try to develop that

然后将其发展至

to become more lifelike.

更接近生命的结构

This is how we can start to make a protocell.

这就是我们创造原始细胞的方法

We use this idea called self-assembly.

我们应用的概念是自我集成

What that means is, I can mix some

意思就是

chemicals together in a test tube in my lab,

在我实验室，我把几种化学物质放进试管

and these chemicals will start to self-associate

这些化学物质通过自我联结

to form larger and larger structures.

形成越来越大的结构

So say on the order of tens of thousands,

于是成千上万的分子

hundreds of thousands of molecules will

经上万次联结

come together to form a large structure

聚集并形成之前不存在的

that didn't exist before.

更大结构

And in this particular example,

在这个具体例子里

what I took is some membrane molecules,

我取了一些膜分子

mixed those together in the right environment,

置于适宜的环境里混合

and within seconds it forms these rather

几秒内就形成了

complex and beautiful structures here.

复杂而美丽的结构

These membranes are also quite similar,

这些膜无论是形态或结构

morphologically and functionally,

都跟你体内的膜分子

to the membranes in your body,

十分相似

and we can use these, as they say,

我们可以用它

to form the body of our protocell.

来形成原始细胞

Likewise,

类似的

we can work with oil and water systems.

可以用在水和油上

As you know, when you put oil and water together,

众所周知水油不容

they don't mix, but through self-assembly

但是通过自我集成

we can get a nice oil droplet to form,

就可以形成油滴

and we can actually use this as a body for

并用此来形成

our artificial organism or for our protocell,

人造组织或者原始细胞

as you will see later.

一会儿你们就能看到了

So that's just forming some body stuff, right?

这只是形成一些形体

Some architectures.

一些结构

What about the other aspects of living systems?

那么生命系统的其他方面呢？

So we came up with this protocell model here

这是我们的原始细胞的

that I'm showing.

模型

We started with a natural occurring clay

我们是从一种叫做蒙脱土的

called montmorillonite.

天然粘土着手

This is natural from the environment, this clay.

这种粘土在环境中自然形成

It forms a surface that is, say, chemically active.

它形成一种具有化学活性的表面

It could run a metabolism on it.

可以在其上进行新成代谢活动

Certain kind of molecules like to associate

有种分子易于这种粘土结合

with the clay. For example, in this case, RNA, shown in red

比如 红的这部分 RNA

-- this is a relative of DNA,

跟DNA相似

it's an informational molecule --

是一种信息分子

it can come along and it starts to associate

它会跟粘土的表面

with the surface of this clay.

结合

This structure, then, can organize the

这个结构就能够在其周围

formation of a membrane boundary around

形成一种膜结构

itself, so it can make a body of

就在周围形成

liquid molecules around itself, and that's

液体分子

shown in green here on this micrograph.

这是显微照片上绿色部分

So just through self-assembly, mixing things

这样通过自我集成

together in the lab, we can come up with, say,

在实验室里混合物质就得到了

a metabolic surface with some

一种能代谢的表面

informational molecules attached

携带有信息分子

inside of this membrane body, right?

存在于膜机体的内部

So we're on a road towards living systems.

这样我们就越来越接近生命系统

But if you saw this protocell, you would not

但是你看到这个原始细胞

confuse this with something that was actually alive.

并不会以为它是真的活细胞

It's actually quite lifeless. Once it forms,

它实际上没有生命

it doesn't really do anything.

形成以后并没有任何活动

So, something is missing.

因此有什么缺失了

Some things are missing.

有些部分缺少了

So some things that are missing is,

这部分就是

for example, if you had a flow of energy

比如说有能量流入一个系统

through a system, what we'd want

我们需要的是

is a protocell that can harvest

一个能采集能量

some of that energy in order to maintain itself,

从而维持自身的原始细胞

much like living systems do.

就像生命系统一样

So we came up with a different protocell

于是我们采用了一个不同的模型

model, and this is actually simpler than the previous one.

这个比之前的更简单

In this protocell model, it's just an oil droplet,

这个模型里只是个油滴

but a chemical metabolism inside

但是其内的化学代谢

that allows this protocell to use energy

能让这个原始细胞利用能量

to do something, to actually become dynamic,

具有动态

as we'll see here.

就像这里看到的

You add the droplet to the system.

把一个油滴加入系统

It's a pool of water, and the protocell

这是一滩水

starts moving itself around in the system.

这个原始细胞就开始在系统里运动

Okay? Oil droplet forms

油滴是通过

through self-assembly, has a chemical

自我集成形成的

metabolism inside so it can use energy,

内部的化学代谢令其能利用能量

and it uses that energy to move itself

让自己在环境中

around in its environment.

动起来

As we heard earlier, movement is very

正如我们所知

important in these kinds of living systems.

运动对生命系统是很重要的

It is moving around, exploring its environment,

它在运动着 探索着周围环境

and remodeling its environment, as you see,

通过形成的这些化学波

by these chemical waves that are forming by the protocell.

来改造环境

So it's acting, in a sense, like a living system

这样它就像一个生命系统一样运动

trying to preserve itself.

去维持自身

We take this same moving protocell here,

我们将同一个运动的原始细胞

and we put it in another experiment,

放入另一个环境

get it moving. Then I'm going

运动起来

to add some food to the system,

我对环境加入食物

and you'll see that in blue here, right?

就是这个蓝色的

So I add some food source to the system.

我对环境加入食物

The protocell moves. It encounters the food.

原始细胞运动着 碰上了食物

It reconfigures itself and actually then

自身重组

is able to climb to the highest concentration

然后到达食物的中心

of food in that system and stop there.

并停留在那里

Alright? So not only do we have this system

这样这个系统里

that has a body, it has a metabolism,

不仅具有机体，并且存在代谢

it can use energy, it moves around.

能消耗能量并运动

It can sense its local environment

能感知周围环境

and actually find resources

并找到环境里的

in the environment to sustain itself.

资源来维持自身

Now, this doesn't have a brain, it doesn't have

但它没有大脑

a neural system. This is just a sack of

没有神经系统

chemicals that is able to have this interesting

只是一堆化学物质

and complex lifelike behavior.

具有类生命的有趣而复杂的行为

If we count the number of chemicals

如果我们算一下系统里的化学物质

in that system, actually, including the water

算上水

that's in the dish, we have five chemicals

有五种化学物质

that can do this.

来做到这个

So then we put these protocells together in a

我们把这些原始细胞

single experiment to see what they would do,

放到一个单一环境里看看会怎样

and depending on the conditions, we have

依据不同的环境

some protocells on the left that are

左边的原始细胞

moving around and it likes to touch the other

四处运动

structures in its environment.

并接触环境里的另一个结构

On the other hand we have two moving

另外一边的两个原始细胞

protocells that like to circle each other,

他们围着对方转圈

and they form a kind of a dance, a complex dance with each other.

好像绕着对方跳着一种复杂的舞

Right? So not only do individual protocells

这样不仅是个体原始细胞

have behavior, what we've interpreted as

有行为特征

behavior in this system, but we also have

就是刚刚看到的在系统内的行为

basically population-level behavior

同时像生物体一样

similar to what organisms have.

有群体行为

So now that you're all experts on protocells,

现在你们都是原始细胞专家

we're going to play a game with these protocells.

下面我们就用这些原始细胞来做个游戏

We're going to make two different kinds.

我们创造了两种原始细胞

Protocell A has a certain kind of chemistry

A具有一种化学物质

inside that, when activated, the protocell

一旦激活

starts to vibrate around, just dancing.

这个原始细胞就开始四处跳动

So remember, these are primitive things,

记住这些是原始物质

so dancing protocells, that's very

所以跳动的原始细胞

interesting to us. (Laughter)

是很有趣的（笑声）

The second protocell has a different

第二种原始细胞有不同的化学物质

chemistry inside, and when activated,

一旦激活

the protocells all come together and they fuse

这些细胞就聚集到一起

into one big one. Right?

然后形成一个大的细胞

And we just put these two together

我们把这两种原始细胞

in the same system.

放到一个系统里

So there's population A,

这是A群体

there's population B, and then

这是B群体

we activate the system,

然后激活系统

and protocell Bs, they're the blue ones,

蓝色群体B

they all come together. They fuse together

它们聚集一起

to form one big blob, and the other protocell

然后形成一个大的

just dances around. And this just happens

其他的则在周围跳动

until all of the energy in the system is

这样一直到

basically used up, and then, game over.

系统的能量耗尽

So then I repeated this experiment

我将此实验重复了几次

a bunch of times, and one time

有一次

something very interesting happened.

发生了很有趣的现象

So, I added these protocells together

我把这些原始细胞加入系统

to the system, and protocell A and protocell B

A原始细胞和B原始细胞

fused together to form a hybrid protocell AB.

结合形成了AB细胞

That didn't happen before. There it goes.

这在之前都没发生过

There's a protocell AB now in this system.

现在系统里有原始细胞AB了

Protocell AB likes to dance around for a bit,

AB会转圈

while protocell B does the fusing, okay?

B会结合

But then something even more interesting happens.

接下来有趣的现象发生了

Watch when these two large protocells,

看看这两个大的细胞

the hybrid ones, fuse together.

这两个合成细胞，结合了

Now we have a dancing protocell

就有了跳动的原始细胞

and a self-replication event. Right. (Laughter)

和自我复制的活动 （笑声）

Just with blobs of chemicals, again.

仅仅是通过化学物质

So the way this works is, you have

这一切发生的机制是

a simple system of five chemicals here,

一个有五种化学物质的简单系统

a simple system here. When they hybridize,

当它们结合的时候

you then form something that's different than

形成新的形态

before, it's more complex than before,

相比之前的更复杂

and you get the emergence of another kind of

这样另一个类生命的

lifelike behavior which

行为就出现了

in this case is replication.

这里是复制

So since we can make some interesting

既然我们能创造有趣的原始细胞

protocells that we like, interesting colors and

有趣的颜色和

interesting behaviors, and they're very easy

有趣的行为

to make, and they have interesting lifelike

而且这不是很难 它们具备有趣的生命特征

properties, perhaps these protocells have

也许这样原始细胞

something to tell us about the origin of life

能揭开地球生命起源的秘密

on the Earth. Perhaps these represent an

也许这代表着

easily accessible step, one of the first steps

简单易行的一步

by which life got started on the early Earth.

当初地球生命开始的那第一步

Certainly, there were molecules present on

当然早期地球肯定存在多种分子

the early Earth, but they wouldn't have been

但是它们肯定不象是

these pure compounds that we worked with

我实验室那些实验里的

in the lab and I showed in these experiments.

纯化合物

Rather, they'd be a real complex mixture of

他们可能是更复杂的

all kinds of stuff, because

混合物

uncontrolled chemical reactions produce

因为不受约制的化学反应

a diverse mixture of organic compounds.

会创造出多种生物结构

Think of it like a primordial ooze, okay?

就像是原始物的稀泥

And it's a pool that's too difficult to fully

很难分类区别这一堆东西

characterize, even by modern methods, and

即使是用现代技术

the product looks brown, like this tar here

产生物就像左边这个焦油一样棕色的

on the left. A pure compound

而纯化合物

is shown on the right, for contrast.

则是右边用于对照的这样

So this is similar to what happens when you

这就像你从厨房取一些

take pure sugar crystals in your kitchen,

纯糖

you put them in a pan, and you apply energy.

放在煎锅里

You turn up the heat, you start making

然后你点上火

or breaking chemical bonds in the sugar,

糖的化学键就断开

forming a brownish caramel, right?

形成棕色的焦糖

If you let that go unregulated, you'll

如果不加控制继续下去

continue to make and break chemical bonds,

就会继续破坏和形成新的化学键

forming an even more diverse mixture of

形成更复杂的分子化合物

molecules that then forms this kind of black

最后就是你煎锅里

tarry stuff in your pan, right, that's

黑乎乎的东西

difficult to wash out. So that's what

很难洗掉

the origin of life would have looked like.

这就是生命最初的样子

You needed to get life out of this junk that

要从45亿前地球上

is present on the early Earth,

这样的混沌里

four, 4.5 billion years ago.

产生生命

So the challenge then is,

挑战就是

throw away all your pure chemicals in the lab,

抛弃实验室里纯化合物

and try to make some protocells with lifelike

而是从那原始物的稀泥里

properties from this kind of primordial ooze.

产生出类生命的原始细胞

So we're able to then see the self-assembly

我们就能看到

of these oil droplet bodies again

那些刚才见到的

that we've seen previously,

油滴的自我集成

and the black spots inside of there

内部那些黑点

represent this kind of black tar -- this diverse,

就代表着黑焦油

very complex, organic black tar.

多样的 非常复杂的 有机黑焦油

And we put them into one of these

我们将其放到你刚刚看到

experiments, as you've seen earlier, and then

那些实验之一

we watch lively movement that comes out.

观察出现的活动

They look really good, very nice movement,

看起来非常有意思

and also they appear to have some kind of

同时也显示出

behavior where they kind of circle

相互转圈相互跟随的

around each other and follow each other,

行为特征

similar to what we've seen before -- but again,

就像我们刚刚看到的

working with just primordial conditions,

强调一下只是在原始物质的条件下

no pure chemicals.

不是纯化学物

These are also, these tar-fueled protocells,

这些焦油原始细胞

are also able to locate resources

也能够在其环境里

in their environment.

定位资源

I'm going to add some resource from the left,

我从左边加入一些资源

here, that defuses into the system,

扩散到整个系统中

and you can see, they really like that.

你能看到它们很喜欢这个

They become very energetic, and able

它们变的非常有活力

to find the resource in the environment,

能找到环境里的资源

similar to what we saw before.

就像我们刚刚看到的

But again, these are done in these primordial

但是这些是在模拟原始的情况下进行的

conditions, really messy conditions,

非常乱糟糟的环境

not sort of sterile laboratory conditions.

而不是无菌的实验室环境

These are very dirty little protocells,

就事实来说

as a matter of fact. (Laughter)

他们是很脏的小小的原始细胞

But they have lifelike properties, is the point.

但是重要的是他们具备生命特征

So, doing these artificial life experiments

这些人造生命实验

helps us define a potential path between

帮助我们找到生命和非生命间的

non-living and living systems.

潜在路径

And not only that, but it helps us

不仅如此

broaden our view of what life is

这也扩展了我们对生命

and what possible life there could be

和生命形式的认识

out there -- life that could be very different

生命也许会和

from life that we find here on Earth.

地球上的生命形式大不相同

And that leads me to the next

这让我想起另外一个词

term, which is "weird life."

“古怪的生命”

This is a term by Steve Benner.

这是史蒂芬･本纳的提法

This is used in reference to a report

美国国家研究委员会在2007年

in 2007 by the National Research Council

的报告中

in the United States, wherein

引用了这个说法

they tried to understand how we can

这个报告旨在研究

look for life elsewhere in the universe, okay,

如何在宇宙中发现其他生命

especially if that life is very different from life

特别是和地球上的生命不一样的生命形式

on Earth. If we went to another planet and

如果我们去另一个星球

we thought there might be life there,

如果那儿有生命的话

how could we even recognize it as life?

我们怎么才知道那是生命呢？

Well, they came up with three very general

他们得出了三个基本标准

criteria. First is -- and they're listed here.

都列在这儿了

The first is, the system has to be in

第一是 系统不能是平衡的

non-equilibrium. That means the system

这意味着系统

cannot be dead, in a matter of fact.

首先不能是死的

Basically what that means is, you have

也就是要有

an input of energy into the system that life

能量输入系统

can use and exploit to maintain itself.

从而生命可以利用并维持自身

This is similar to having the Sun shining

这就像太阳照着地球

on the Earth, driving photosynthesis,

促进光合作用

driving the ecosystem.

和生态系统

Without the Sun, there's likely to be

没有太阳

no life on this planet.

就没有生命

Secondly, life needs to be in liquid form,

第二 生命应该是液体形式

so that means even if we had some

因为就算存在

interesting structures, interesting molecules

有趣的结构或者分子

together but they were frozen solid,

但如果他们完全是固体形态

then this is not a good place for life.

那就不是适合生命的地方

And thirdly, we need to be able to make

第三 要能够断开

and break chemical bonds. And again

和结合化学键

this is important because life transforms

这很重要

resources from the environment into

因为生命要能够将环境中的资源

building blocks so it can maintain itself.

转化为维持自身的基本单元

Now today, I told you about very strange

今天我给你们介绍了

and weird protocells -- some that contain clay,

奇怪的原始细胞－有些含有粘土

some that have primordial ooze in them,

有些有原始物的稀泥

some that have basically oil

有些含的基本是油

instead of water inside of them.

而不是水

Most of these don't contain DNA,

这些大部分不含DNA

but yet they have lifelike properties.

但具备类生命的特征

But these protocells satisfy

但是这些原始细胞具有

these general requirements of living systems.

生命系统的这几项基本条件

So by making these chemical, artificial

通过人造生命的实验

life experiments, we hope not only

我们希望

to understand something fundamental

对生命起源

about the origin of life and the existence

和其他星球生命的存在与否

of life on this planet, but also

有更好的了解

what possible life there could be

也对宇宙里

out there in the universe. Thank you.

可能存在的生命有更多认识 谢谢

(Applause)

（掌声）