这种病毒本不该存在（但它确实存在）：英语精读讲义

Hidden in the microverse all around you, 表達脈絡

隐藏在你周围的微观世界中，

there's a merciless war being fought by the true rulers of this planet, 語法

这颗星球的真正统治者正在进行一场残酷的战争，

microorganisms.

它们就是微生物。

Amebae,

变形虫、

protists,

原生生物、

bacteria,

细菌、

archaea,

古菌，

and fungi compete for resources and space.

以及真菌都在争夺资源和空间。

And then there are the strange horrors that are viruses

然而还有一些如同可怕怪物般的病毒，

hunting everyone else.

正在猎杀其他所有生物。

Not even alive,

它们甚至不能算作生命，

they are the tiniest, most abundant,

却是地球上最小、最丰富、

and deadliest beings on Earth,

最致命的存在，

killing trillions every day.

每天都会杀死数以万亿计的生物。

Not interested in resources, 表達脈絡

它们对资源不感兴趣，

only in living things to take over. 短語動詞

只想占据活着的生物。

Or so we thought. 表達脈絡

我们原以为就是这样了。

Turns out there are giant viruses 短語搭配

但事实证明，还有一种巨型病毒

that blur the line between life and death, 習語

模糊了生与死的界限，

and other viruses

以及其他

hunting them.

专门猎杀它们的病毒。

considerably smaller than your cells or even bacteria,

病毒比你的细胞甚至比细菌还要小得多，

viruses are nothing but a hull, 短語搭配

它们不过是个外壳，

a tiny bit of genetic material,

包含一丁点遗传物质，

and a few proteins.

以及少量蛋白质。

No metabolism,

它们没有新陈代谢，

no way to propel themselves, 語法

无法自己移动，

no will or ambition.

也没有意志或野心。

They float around aimlessly

它们只是漫无目的地四处漂浮，

and hope to stumble upon a victim to infect and take over. 短語動詞

期待能偶然碰上一个受害者来感染并占据。

Viruses are so simple 語法

病毒是如此简单，

that we're not sure if they should count as living things or not. 短語搭配

以至于我们不确定它们是否应算作生物。

Some scientists argue viruses are alive,

一些科学家认为病毒是活着的，

others think that the cells they infect are the actual living viruses,

另一些人则认为被它们感染的细胞才是真正的活病毒，

hybrid organisms called virocells,

也就是被称为病毒细胞（virocells）的混合生物，

and the viral particles are more like seeds or spores. 語法

而病毒颗粒更像是种子或孢子。

And many others think viruses are just dead material.

还有许多人认为病毒只是无生命的死物。

The origin of viruses is a mystery

病毒的起源是个谜，

because how can something that needs victims to make more of itself emerge in the first place? 短語搭配

因为一个需要受害者才能自我繁殖的东西，最初是怎么出现的呢？

There are many ideas.

对此有很多猜测。

Viruses may have been essential steps in the emergence of life,

病毒可能是生命起源过程中不可或缺的步骤，

or maybe they started out as escaped DNA from cells 短語動詞

或者它们最初可能只是从细胞中逃逸出来的DNA，

that became really good at making copies of themselves. 短語搭配

后来变得非常擅长复制自己。

Maybe they are the descendants of truly lazy parasites

也许它们是极其懒惰的寄生虫的后代，

that let others do all the work for them. 語法

让别人替它们完成所有的工作。

The current thinking is that viruses probably emerged multiple times from different origins, 表達脈絡

目前的观点是，病毒可能是从不同起源中多次独立出现的，

but we simply don't know for sure yet. 短語搭配

但我们现在还无法确定。

Whatever the truth is, 語法

无论真相如何，

viruses are the most successful beings on this planet.

病毒都是这个星球上最成功的存在。

There's an estimated 10,000 billion billion billion viruses on Earth. 語法

据估计，地球上大约有1000万亿亿亿个病毒。

If we put them all next to each other, 語法

如果把它们全排成一列，

they would stretch for 100 million light years,

可以绵延1亿光年，

500 Milky Way galaxies wide.

相当于500个银河系的宽度。

Very recently,

就在最近，

viruses became even weirder when scientists found a completely new type,

当科学家发现了一种全新类型的病毒后，病毒变得更加离奇了，

giant viruses nicknamed GIRUS.

它就是被称为巨型病毒（GIRUS）的存在。

Not only did it break all sorts of records, 語法

它不仅打破了各种记录，

but questioned many assumptions we had about their nature.

还让我们质疑了许多关于病毒本质的假设。

Giruses even come with their own parasites,

巨型病毒甚至有自己的寄生虫——

virophages,

噬病毒体（virophages），

viruses that hunt other viruses,

这是一种猎杀其他病毒的病毒，

which seemingly makes no sense at all. 短語搭配

这听起来简直毫无道理。

And since we identified the first one in 2003,

自从2003年发现第一个巨型病毒以来，

it seems like these giants are everywhere we look. 語法

似乎我们目光所及之处都有这些巨无霸的踪影。

In the oceans,

在海洋中、

in water towers,

在水塔里、

in the guts of pigs,

在猪的肠道里，

and the mouths of humans.

以及人类的口腔中。

And they're even weirder than we thought.

而且它们比我们想象的还要离奇。

Giruses look funny,

巨型病毒看起来很滑稽，

like hairy geometric forms

像长毛的几何图形，

or mini pickles,

或是迷你酸黄瓜，

much larger than all viruses we knew before,

它们比我们以前知道的所有病毒都要大得多，

which explains how they could hide in plain sight for centuries. 習語

这解释了它们为何能在几个世纪里隐藏在众目睽睽之下。

Scientists saw them under their microscopes and just thought they had to be bacteria. 語法

科学家在显微镜下看到它们时，只觉得它们肯定是细菌。

It's like suddenly discovering there are elephant-sized ducks everywhere. 表達脈絡

这就像突然发现到处都有大象那么大的鸭子一样。

Most giruses we've found so far 短語搭配

到目前为止我们发现的大多数巨型病毒，

hunt amebae and other single-celled beings.

都在猎杀变形虫和其他单细胞生物。

When they find a victim,

当它们找到受害者时，

they connect with it and use its natural processes to enter the cell.

会与之结合，并利用细胞自身的自然过程进入细胞内部。

Like all viruses,

像所有病毒一样，

their goal is to misappropriate the victim's infrastructure and procreate. 用詞

它们的目标是挪用受害者的基础设施来繁殖。

Imagine a mouse crawling into your mouth and using your guts and bones and fat tissue to build a mouse factory. 表達脈絡

想象一下，一只老鼠爬进你的嘴里，利用你的肠子、骨骼和脂肪组织建造了一个老鼠工厂。

The girus unloads its attack proteins and genetic material and rearranges the cell from the inside.

巨型病毒释放出它的攻击蛋白和遗传物质，从内部对细胞进行重组。

Its structural elements,

细胞的结构元素、

protein production machinery,

蛋白质生产机器，

and large amounts of mitochondria for energy are changed to become an actual factory called viroplasm.

以及大量用于提供能量的线粒体，都被改造成了一个真正的工厂，叫做病毒基质（viroplasm）。

Some giruses even construct a membrane to shield them from the cell's antiviral defenses. 短語搭配

有些巨型病毒甚至会建立一层膜，以保护它们免受细胞抗病毒防御系统的攻击。

Once finished, 語法

完工之后，

the viroplasm begins to assemble new giruses using the victim up from the inside until it's filled up. 講解

病毒基质开始从内部消耗受害者来组装新的巨型病毒，直到把细胞填满。

Finally,

最后，

the invader usually orders the cell to self-destruct 語法

入侵者通常会命令细胞自毁，

and releases new giruses to look for new prey.

并释放新的巨型病毒去寻找新猎物。

But what makes giruses special is not their modus operandi or their size even, 語法

但让巨型病毒与众不同的，并不是它的作案手法，甚至也不是它的大小，

it's that they are much more complex than thought possible for a virus.

而是它们的复杂程度，远远超出了我们对病毒的预期。

Your cells have around 20,000 genes.

你的细胞有大约20000个基因。

A typical bacterium has a few thousand genes.

一个典型的细菌有几千个基因。

The coronavirus has around 15,

冠状病毒有大约15个，

HIV or the flu around 10.

艾滋病毒或流感病毒大约有10个。

The number of genes alone is certainly not everything. 短語搭配

基因的数量当然不能说明一切。

The tomato,

番茄，

for example,

例如，

has 35,000 genes.

拥有35000个基因。

But generally,

但总的来说，

we think of life as a complex system. 短語搭配

我们把生命看作是一个复杂的系统。

So below a certain complexity level,

因此，在一定的复杂程度之下，

something may be closer to dead material rather than a living organism. 語法

某种东西可能更接近于死物，而不是活的生物体。

But giruses can have hundreds or even thousands of genes,

但巨型病毒可以有数百甚至数千个基因，

blurring the line between living and dead things.

这模糊了生物与死物之间的界限。

And it's not just the numbers that are special, 語法

不仅是数量惊人，

but also what these genes do.

这些基因的功能也很特别。

We used to think of viral genes as the simplest of instructions, 語法

过去我们认为病毒基因是最简单的指令，

just enough to overcome the defense of their victims and make new viruses. 語法

仅仅足以攻破受害者的防御并制造新病毒。

But many girus genes are completely unique,

但许多巨型病毒的基因是完全独一无二的，

basically mystery genes.

基本上就是神秘基因。

Even more confusing,

更令人困惑的是，

a huge selection of their genes that are actually hallmarks of living things, 短語搭配

它们很大一部分基因实际上具有生物的典型特征，

genes that regulate nutrient intake,

比如调节营养摄入、

energy production,

能量生产、

light harvesting,

捕光、

replication,

复制，

or are just necessary to keep cells alive.

或者仅仅是维持细胞存活所必需的基因。

Some recent studies have even suggested that some giruses with very complex genomes

最近一些研究甚至表明，某些基因组极其复杂的巨型病毒

may be able to maintain a basic level of metabolism on their own, 短語搭配

也许能自己维持基本的新陈代谢，

which if true, 語法

如果这是真的，

will shake up what we thought of viruses even more. 短語動詞

这将彻底颠覆我们对病毒的认知。

We still don't know anything for sure,

虽然我们现在还无法确定，

but one idea about girus genes is that they might fundamentally alter the physiology and evolution of their victims

但关于巨型病毒基因的一个想法是，它们可能会从根本上改变受害者的生理和进化轨迹，

by integrating their own genomes and merging with them into chimeric organisms. 語法

做法是将自身的基因组与受害者融合，形成嵌合生物。

Or the other way. around,

或者反过来，

take some host genes with them,

带走一些宿主基因，

and be changed themselves.

并因此改变自己。

For billions of years,

几十亿年来，

giruses may have been existing alongside and infecting cells,

巨型病毒可能一直与细胞并存并感染它们，

exerting an unseen influence on the development of life. 短語搭配

在看不见的地方影响着生命的发展。

Not just as a parasite, 表達脈絡

它们不仅是寄生虫，

but jerking evolution in different directions by mixing genes around in all directions.

还在向四面八方混合基因的过程中，将进化拉向不同的方向。

Which brings us to another unique thing about them, 表達脈絡

这又引出了它们的另一个独特之处：

virophages,

噬病毒体，

the viruses hunting giruses.

即猎杀巨型病毒的病毒。

The concept itself is a bit mind-boggling.

这个概念本身就有点令人难以置信。

How can a thing that might be dead

一个可能是死物的东西

hunt another thing that might be dead too?

怎么去猎杀另一个也可能是死物的东西呢？

Let's look at one of them.

让我们来看看其中之一。

The virophage Sputnik is hunting a girus called Mamavirus that itself is hunting amebae.

一种叫“斯普特尼克”（Sputnik）的噬病毒体，专门猎杀一种本身在猎杀变形虫的“妈妈病毒”（Mamavirus）。

Sputnik is a tiny minimalistic virus that doesn't even have the genes and tools to replicate itself.

斯普特尼克是一种极简的微小病毒，甚至没有自我复制的基因和工具。

What it does have is the ability to hijack the viroplasm factories of Mamaviruses. 語法

但它拥有劫持妈妈病毒的病毒基质工厂的能力。

So virophages need their victim, 語法

所以，噬病毒体需要它们的受害者——

the girus,

巨型病毒，

to infect their victim,

去感染它们的受害者，

an ameba,

即变形虫，

first,

作为第一步，

and then they can parasitize it.

然后它们才能进行寄生。

A Mamavirus viroplasm infected by Sputnik can only produce very few new giruses,

被斯普特尼克感染的妈妈病毒基质，只能制造出极少量的巨型病毒，

and among these, many are deformed and broken, 表達脈絡

而且其中很多还是畸形、破损的，

unable to infect further cells. 語法

无法再去感染其他细胞。

Instead, 表達脈絡

相反，

it makes loads of new Sputnik virophages.

它制造出了大量新的斯普特尼克噬病毒体。

Other virophages are even more subtle.

其他一些噬病毒体甚至更为狡猾。

When they infect a viroplasm,

当它们感染病毒基质时，

they just integrate their genetic code into the newly produced giruses, 短語搭配

它们只是将自己的遗传密码整合到新产生的巨型病毒中，

like sleeper agents. 習語

就像潜伏的特工一样。

The next time one of these infiltrated giruses successfully infects a 語法

下一次，当这些被渗透的巨型病毒成功感染一个

cell, it produces mostly virophages instead of giruses. 語法

细胞时，它产生的大多会是噬病毒体，而不是巨型病毒。

Giruses are not completely defenseless, 語氣意圖

巨型病毒并非完全没有防御能力，

though.

不过。

A few years ago,

几年前，

the world was in awe when scientists discovered CRISPR, 短語搭配

当科学家发现 CRISPR 时，震惊了世界，

a bacteria defense system against viruses.

这是一种细菌抵御病毒的防御系统。

It turns out some giruses have a system that might be similar,

事实证明，一些巨型病毒也有一个可能类似的系统，

a sort of girus immune system against virophages. 短語搭配

这是一种巨型病毒针对噬病毒体的免疫系统。

In turn, 表達脈絡

反过来，

virophages can also be used as an anti-girus defense mechanism by living cells. 語法

噬病毒体也能被活细胞用作对抗巨型病毒的防御机制。

Some protists have been found that integrated the genetic code of virophages into their genome and kept it.

科学家发现某些原生生物已将噬病毒体的遗传密码整合到自己的基因组中并保留下来。

When the protists were infected by giruses,

当这些原生生物被巨型病毒感染时，

they used the code to create virophages themselves to take over the girus factories.

它们会利用该代码自己制造出噬病毒体，从而接管巨型病毒的工厂。

In the end,

虽然最终，

the protist would still be killed by the girus infection,

原生生物仍会被巨型病毒的感染杀死，

but instead of releasing giruses to kill its buddies, 語法

但它释放的不再是去杀死同伴的巨型病毒，

it released virophages to hunt them.

而是去猎杀这些病毒的噬病毒体。

The amazing thing about everything we've told you in this video is that we're still very much at the beginning. 習語

这个视频里告诉你的一切，最奇妙的地方在于，我们仍处于探索的起步阶段。

It's not even been 20 years since the discovery of giruses and virophages. 語法

距离巨型病毒和噬病毒体被发现甚至还不到20年。

There is so much going on in the microverse.

在微观世界中，还有太多未知的事情正在发生。

Life is not an isolated event, 習語

生命绝非孤立的事件，

but a ping-pong game of trillions of organisms and viruses.

而是万亿计的生物体和病毒之间的一场“乒乓球赛”。

So when you feel down and like there's not that much new to discover, 語法

所以，当你感到沮丧，觉得似乎没什么新事物可被发现时，

think of giruses and all the other elephant-sized ducks all around us,

想想巨型病毒，以及我们周围其他“大象般大小的鸭子”吧，

invisible until we look more closely. 表達脈絡

它们只是隐形了，直到我们凑近仔细观察才会显现。