人体奥妙之细胞的暗战（2012）

called proteasomes,
碎成小构建模块
reducing them to tiny building blocks
用以构成新蛋白质
for new proteins.
然而每个细胞都属于
But each cell is also part of
一个细胞群区
a wider neighbourhood of cells,
需要不断地交流互动
all continually communicating with each other.
这些蛋白质碎块
Fragments of shredded proteins
不停地被运到细胞表面
are constantly transported to the surface.
它们将在这里接受视察
Here, they are presented for inspection…
检察官便是我们体内
to be monitored by the guardians of
免疫系统的守护者
our body’s immune system…
白细胞
our white blood cells.
这些”巡逻士兵”会检查蛋白质碎块
These “roving soldiers” check the protein fragments
是否有坏损或感染的迹象
for signs of damage or infection.
此时 一切都还井然有序
And for the moment, everything is in order.
人类的每一个细胞都包含
Every single human cell contains
一个极为复杂 令人惊叹的世界
this world of breathtaking complexity,
它们听从其核心 细胞核的指挥
organised by the nuclear machines at its heart,
永不停歇地执行着DNA的指令
ceaselessly working from instructions written down in our DNA.
然而我们的细胞也在不断遭受攻击
But our cells are under constant attack,
这个细胞将要面对的
and this cell is about to face
是位宿敌
an ancient enemy…
引发这种抗衡的起因非常普通
in an encounter that starts with an event so commonplace…
你甚至都不会察觉
you seldom even notice it.
我们每天都在遭受
Every day our bodies are constantly bombarded
这些无形生物的频频轰炸
by these invisible critters,
细菌与病毒
bacteria and viruses.
我们有皮肤
But we have our skin,
作为第一道防线抵挡它们入侵
our first line of defence that keeps them out.
但我们也有致命的弱点
But we have Achilles’ heels.
我们的嘴巴鼻子是通往外界的开放通道
We have openings to the outside world our mouths, our noses.
我们会触碰物体 会摸嘴唇
We touch things. We rub our lips.
揉眼睛 擦鼻子
We rub our eyes or wipe our nose.
它们得以入侵
They can get in.
一旦进来了 就无法驱逐
And once they’re in, they’re in.
这支”外来大军”
Inhaled from a sneeze,
通过喷嚏传播 被吸入我们体内
an alien “army” is being carried into our body.
无数的入侵者一心来搞破坏
A million invaders, hellbent on destruction.
这就是我们最常见的敌人
This is one of our most common enemies,
腺病毒
the adenovirus.
这种病毒设计精良
It’s a masterpiece of design,
每个都只抱着一个目标
and each one has a single aim…
突破细胞的重重防线
to breach a cell’s defences
入侵细胞核
and reach the nucleus.
但凡有一个病毒进入细胞核
Once inside, any one of these viruses
就能控制整个细胞
can take control of the cell…
并在细胞内繁殖不下万次
and reproduce 10,000 times over.
这可导致各种后果
The result could be anything,
可能是普通感冒
from the common cold
也可能是肺炎
to pneumonia,
甚至是死亡
even death.
但我们的机体已经准备好了
But our bodies are prepared.
当病毒接近细胞时
As the viruses approach the cell,
将会受到第一重抵抗
they are met by a cloud of resistance.
它们便是抗体
Antibodies,
这种Y形蛋白会识别外来入侵者
Y-shaped proteins that identify alien intruders,
它们在细胞之间来回巡逻
patrol the space between our cells,
监控是否有病毒
looking for viruses.
一旦识别出入侵者
Recognising the invader,
抗体会将自己紧锁于病毒的”盔甲”上
they lock to the virus’s “armour plating,”
将它们连环镣铐 使它们变成
shackling them together, making the viruses easy meat
专门吞噬外侵者的白细胞的盘中餐
for the white blood cells that feed on alien invaders like these.
抗体和白细胞联手组成了
Antibodies and white blood cells form the front line
人体免疫系统的第一道防线
of our immune system.
免疫系统着实令人惊叹
The immune system is certainly amazing,
它不断进化 能识别并消灭
and it actually evolved to see invading microbes
入侵的微生物
and get rid of them.
而那仅仅是你身体防御的一部分
But that’s just one part of your body’s defences.
人体在抵抗病毒各个阶段的功能
Our DNA encodes all these other features that help us
均被编码为DNA
to fight against virus at every single step.
尽管身体迅速做出免疫应答
Despite the body’s early immune response
成千上万的病毒仍然能冲过防线
hundreds of thousands of viruses make it through to our cell.
但在细胞表面 它们遇到了下一道阻碍
But at the surface, they face their next obstacle,
细胞膜 即细胞的皮肤
the cell’s membrane, or skin.
细胞表面十分复杂
The surface of the cell is an amazingly complicated place.
成百上千的受体蛋白
There are hundreds, maybe thousands of receptor proteins
苏珊娜·比德古德
剑桥大学
从细胞表面伸出
sticking out of the cell
它们各自拥有独特的功能
and they all have a unique function to play.
其中一些会将信息
Some of them will be just transporting information
从细胞外传递到细胞内
from outside of the cell into the cell.
其他一些则可将整个货物运进去
Other receptors can bring whole cargoes in.
每个细胞膜都是个动态保护层
The surface of each cell is a living barrier,
饱含掌管物质进出的
teeming with security proteins that constantly monitor molecules
监控蛋白质
as they enter and leave.
小分子 如水和氧气
Small molecules like water and oxygen
可以直接穿过细胞膜
can simply seep through the membrane.
大一些的分子 例如糖
Larger molecules, like sugar,
则必须通过专用泵进入细胞
are allowed entry through specialised pumps.
而最大的分子若想进入细胞
But the largest deliveries require a special key
则需要一把特制钥匙
before they are allowed into the cell.
在细胞表面不停巡逻的哨兵们
These protein keys are recognised by teams of mobile sentries
会识别这些蛋白钥匙
that continually roam the surface.
这套精密的系统防止有害分子
This sophisticated system is designed to keep harmful molecules
进入细胞内部
out of the cell.
但是经过数十亿年的进化
But over billions of years of evolution,
腺病毒演变出了自己的钥匙
the adenovirus has evolved its very own key,
就镶在这些突出的纤维尾部
etched into the end of these projecting fibres.
抗体仍会附着在其中一些纤维上
Antibodies still cling to the some of these fibres,
封锁住大部分伪造的钥匙 但并非全部
blocking many of the counterfeit keys – but not all.
逐个地 细胞表面的哨兵被欺骗
One by one, sentries all over the cell’s surface are fooled.
病毒大军潜入了细胞内部
And the virus army quietly slips inside.
在这与细胞的较量中
In this ancient battle for the cell,
病毒在第二关胜出
it’s round two to the virus.
细胞与病毒之间的这个猫鼠游戏
So, how far back does it go, this cat and mouse game,
尼克·莱恩博士
伦敦学院大学
是从何开始的呢
this battle between cells and viruses?
所有迹象表明 早在地球出现生命的初始
Every indication suggests it goes right back
战争就已打响
to the origins of life on Earth.
生命在初始期便出现分化
Wherever life started, very early on there was a divergence,
朝着两种截然不同的方向发展
two different strategies that life followed.
一种变得更复杂 变成细胞
One of them was to become more complex, to become cells,
最终 进化成我们这样的有机体
to become, ultimately, organisms like ourselves.
另一种则保持最简单的构造 例如病毒
The other way was to remain simple – to become viruses,
并且利用细胞为自己服务
and to exploit those cells to their own ends,
进行自我复♥制♥
to replicate themselves.
表膜之下
Beneath the surface,
细胞做好了迎接这些致命入侵者的准备
the cell prepares to receive the deadly invaders.
误将病毒认作重要营养物的细胞
Fooled into thinking that the virus is an important nutrient,
指示特殊的蛋白质汇聚成一个球体
special proteins slot together to form a spherical mould.
它们从细胞膜上掐出一个囊泡
They pinch out a bubble of cellular membrane,
将病毒包裹在内
wrapping the virus inside.
最终 一个分离蛋白将囊泡释放
Finally, a separate protein pinches the bubble free,
将病毒运入细胞内部
delivering the virus into the cell’s interior.
无意之中 细胞促成了
Unwittingly, the cell has just taken a large step
自己的衰亡
towards to its own downfall.
这支入侵病毒大军中的每个成员
Every single member of this invading virus army
都携带了足以摧毁细胞的致命武器
has the weaponry to ultimately destroy this cell.
它的蛋白质衣壳含藏多层伪装
Its protein shell is a multi-layered cloak of deception,
仍然留有几手骗术
which has still more surprises in store.
在其内核 携带了一小束DNA