這種病毒本不該存在（但它確實存在）：英語精讀講義

Hidden in the microverse all around you, 表達脈絡

隱藏在你周圍的微觀世界中，

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

這顆星球的真正統治者正在進行一場殘酷的戰爭，

microorganisms.

牠們就是微生物。

Amebae,

變形蟲、

protists,

原生生物、

bacteria,

細菌、

archaea,

古菌，

and fungi compete for resources and space.

以及真菌都在爭奪資源和空間。

And then there are the strange horrors that are viruses

然而還有一些如同可怕怪物般的病毒，

hunting everyone else.

正在獵殺其他所有生物。

Not even alive,

牠們甚至不能算作生命，

they are the tiniest, most abundant,

卻是地球上最小、最豐富、

and deadliest beings on Earth,

最致命的存在，

killing trillions every day.

每天都會殺死數以萬億計的生物。

Not interested in resources, 表達脈絡

牠們對資源不感興趣，

only in living things to take over. 片語動詞

只想佔據活著的生物。

Or so we thought. 表達脈絡

我們原以為就是這樣了。

Turns out there are giant viruses 片語搭配

但事實證明，還有一種巨型病毒

that blur the line between life and death, 慣用語

模糊了生與死的界線，

and other viruses

以及其他

hunting them.

專門獵殺牠們的病毒。

considerably smaller than your cells or even bacteria,

病毒比你的細胞甚至比細菌還要小得多，

viruses are nothing but a hull, 片語搭配

牠們不過是個外殼，

a tiny bit of genetic material,

包含一丁點遺傳物質，

and a few proteins.

以及少量蛋白質。

No metabolism,

牠們沒有新陳代謝，

no way to propel themselves, 文法

無法自己移動，

no will or ambition.

也沒有意志或野心。

They float around aimlessly

牠們只是漫無目的地四處漂浮，

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

期待能偶然碰上一個受害者來感染並佔據。

Viruses are so simple 文法

病毒是如此簡單，

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

以至於我們不確定牠們是否應算作生物。

Some scientists argue viruses are alive,

一些科學家認為病毒是活著的，

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

另一些人則認為被牠們感染的細胞才是真正的活病毒，

hybrid organisms called virocells,

也就是被稱為病毒細胞（virocells）的混合生物，

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

而病毒顆粒更像是種子或孢子。

And many others think viruses are just dead material.

還有許多人認為病毒只是無生命的死物。

The origin of viruses is a mystery

病毒的起源是個謎，

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

因為一個需要受害者才能自我繁殖的東西，最初是怎麼出現的呢？

There are many ideas.

對此有很多猜測。

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

病毒可能是生命起源過程中不可或缺的步驟，

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

或者牠們最初可能只是從細胞中逃逸出來的DNA，

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

後來變得非常擅長複製自己。

Maybe they are the descendants of truly lazy parasites

也許牠們是極其懶惰的寄生蟲的後代，

that let others do all the work for them. 文法

讓別人替牠們完成所有的工作。

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

目前的觀點是，病毒可能是從不同起源中多次獨立出現的，

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

但我們現在還無法確定。

Whatever the truth is, 文法

無論真相如何，

viruses are the most successful beings on this planet.

病毒都是這個星球上最成功的存在。

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

據估計，地球上大約有1000萬億億億個病毒。

If we put them all next to each other, 文法

如果把牠們全排成一列，

they would stretch for 100 million light years,

可以綿延1億光年，

500 Milky Way galaxies wide.

相當於500個銀河系的寬度。

Very recently,

就在最近，

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

當科學家發現了一種全新類型的病毒後，病毒變得更加離奇了，

giant viruses nicknamed GIRUS.

牠就是被稱為巨型病毒（GIRUS）的存在。

Not only did it break all sorts of records, 文法

牠不僅打破了各種記錄，

but questioned many assumptions we had about their nature.

還讓我們質疑了許多關於病毒本質的假設。

Giruses even come with their own parasites,

巨型病毒甚至有自己的寄生蟲——

virophages,

噬病毒體（virophages），

viruses that hunt other viruses,

這是一種獵殺其他病毒的病毒，

which seemingly makes no sense at all. 片語搭配

這聽起來簡直毫無道理。

And since we identified the first one in 2003,

自從2003年發現第一個巨型病毒以來，

it seems like these giants are everywhere we look. 文法

似乎我們目光所及之處都有這些巨無霸的蹤影。

In the oceans,

在海洋中、

in water towers,

在水塔裡、

in the guts of pigs,

在豬的腸道裡，

and the mouths of humans.

以及人類的口腔中。

And they're even weirder than we thought.

而且牠們比我們想像的還要離奇。

Giruses look funny,

巨型病毒看起來很滑稽，

like hairy geometric forms

像長毛的幾何圖形，

or mini pickles,

或是迷你酸黃瓜，

much larger than all viruses we knew before,

牠們比我們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. 慣用語

這解釋了牠們為何能在幾個世紀裡隱藏在眾目睽睽之下。

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

科學家在顯微鏡下看到牠們時，只覺得牠們肯定是細菌。

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

這就像突然發現到處都有大象那麼大的鴨子一樣。

Most giruses we've found so far 片語搭配

到目前為止我們發現的大多數巨型病毒，

hunt amebae and other single-celled beings.

都在獵殺變形蟲和其他單細胞生物。

When they find a victim,

當牠們找到受害者時，

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

會與之結合，並利用細胞自身的自然過程進入細胞內部。

Like all viruses,

像所有病毒一樣，

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

牠們的目標是挪用受害者的基礎設施來繁殖。

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

想像一下，一隻老鼠爬進你的嘴裡，利用你的腸子、骨骼和脂肪組織建造了一個老鼠工廠。

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

巨型病毒釋放出牠的攻擊蛋白和遺傳物質，從內部對細胞進行重組。

Its structural elements,

細胞的結構元素、

protein production machinery,

蛋白質生產機器，

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

以及大量用於提供能量的粒線體，都被改造成了一個真正的工廠，叫做病毒基質（viroplasm）。

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

有些巨型病毒甚至會建立一層膜，以保護牠們免受細胞抗病毒防禦系統的攻擊。

Once finished, 文法

完工之後，

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

病毒基質開始從內部消耗受害者來組裝新的巨型病毒，直到把細胞填滿。

Finally,

最後，

the invader usually orders the cell to self-destruct 文法

入侵者通常會命令細胞自毀，

and releases new giruses to look for new prey.

並釋放新的巨型病毒去尋找新獵物。

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

但讓巨型病毒與眾不同的，並不是牠的作案手法，甚至也不是牠的大小，

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

而是牠們的複雜程度，遠遠超出了我們對病毒的預期。

Your cells have around 20,000 genes.

你的細胞有大約20000個基因。

A typical bacterium has a few thousand genes.

一個典型的細菌有幾千個基因。

The coronavirus has around 15,

冠狀病毒有大約15個，

HIV or the flu around 10.

愛滋病毒或流感病毒大約有10個。

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

基因的數量當然不能說明一切。

The tomato,

番茄，

for example,

例如，

has 35,000 genes.

擁有35000個基因。

But generally,

但總的來說，

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

我們把生命看作是一個複雜的系統。

So below a certain complexity level,

因此，在一定的複雜程度之下，

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

某種東西可能更接近於死物，而不是活的生物體。

But giruses can have hundreds or even thousands of genes,

但巨型病毒可以有數百甚至數千個基因，

blurring the line between living and dead things.

這模糊了生物與死物之間的界線。

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

不僅是數量驚人，

but also what these genes do.

這些基因的功能也很特別。

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

過去我們認為病毒基因是最簡單的指令，

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

僅僅足以攻破受害者的防禦並製造新病毒。

But many girus genes are completely unique,

但許多巨型病毒的基因是完全獨一無二的，

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, 片語搭配

牠們很大一部分基因實際上具有生物的典型特徵，

genes that regulate nutrient intake,

比如調節營養攝入、

energy production,

能量生產、

light harvesting,

捕光、

replication,

複製，

or are just necessary to keep cells alive.

或者僅僅是維持細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，某些基因組極其複雜的巨型病毒

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

也許能自己維持基本的新陳代謝，

which if true, 文法

如果這是真的，

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

這將徹底顛覆我們對病毒的認知。

We still don't know anything for sure,

雖然我們現在還無法確定，

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

但關於巨型病毒基因的一個想法是，牠們可能會從根本上改變受害者的生理和演化軌跡，

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

做法是將自身的基因組與受害者融合，形成嵌合生物。

Or the other way. around,

或者反過來，

take some host genes with them,

帶走一些宿主基因，

and be changed themselves.

並因此改變自己。

For billions of years,

幾十億年來，

giruses may have been existing alongside and infecting cells,

巨型病毒可能一直與細胞並存並感染牠們，

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

在看不見的地方影響著生命的發展。

Not just as a parasite, 表達脈絡

牠們不僅是寄生蟲，

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

還在向四面八方混合基因的過程中，將演化拉向不同的方向。

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

這又引出了牠們的另一個獨特之處：

virophages,

噬病毒體，

the viruses hunting giruses.

即獵殺巨型病毒的病毒。

The concept itself is a bit mind-boggling.

這個概念本身就有點令人難以置信。

How can a thing that might be dead

一個可能是死物的東西

hunt another thing that might be dead too?

怎麼去獵殺另一個也可能是死物的東西呢？

Let's look at one of them.

讓我們來看看其中之一。

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

一種叫「史普尼克」（Sputnik）的噬病毒體，專門獵殺一種本身在獵殺變形蟲的「媽媽病毒」（Mamavirus）。

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

史普尼克是一種極簡的微小病毒，甚至沒有自我複製的基因和工具。

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

但牠擁有劫持媽媽病毒的病毒基質工廠的能力。

So virophages need their victim, 文法

所以，噬病毒體需要牠們的受害者——

the girus,

巨型病毒，

to infect their victim,

去感染牠們的受害者，

an ameba,

即變形蟲，

first,

作為第一步，

and then they can parasitize it.

然後牠們才能進行寄生。

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

被史普尼克感染的媽媽病毒基質，只能製造出極少量的巨型病毒，

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

而且其中很多還是畸形、破損的，

unable to infect further cells. 文法

無法再去感染其他細胞。

Instead, 表達脈絡

相反，

it makes loads of new Sputnik virophages.

牠製造出了大量新的史普尼克噬病毒體。

Other virophages are even more subtle.

其他一些噬病毒體甚至更為狡猾。

When they infect a viroplasm,

當牠們感染病毒基質時，

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

牠們只是將自己的遺傳密碼整合到新產生的巨型病毒中，

like sleeper agents. 慣用語

就像潛伏的特工一樣。

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

下一次，當這些被滲透的巨型病毒成功感染一個

cell, it produces mostly virophages instead of giruses. 文法

細胞時，牠產生的大多會是噬病毒體，而不是巨型病毒。

Giruses are not completely defenseless, 語氣意圖

巨型病毒也並非毫無防禦能力，

though.

不過。

A few years ago,

幾年前，

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

當科學家發現 CRISPR 時，震驚了世界，

a bacteria defense system against viruses.

這是一種細菌抵禦病毒的防禦系統。

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

事實證明，一些巨型病毒也有一個可能類似的系統，

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

這是一種巨型病毒針對噬病毒體的免疫系統。

In turn, 表達脈絡

反過來，

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

噬病毒體也能被活細胞用作對抗巨型病毒的防禦機制。

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

科學家發現某些原生生物已將噬病毒體的遺傳密碼整合到自己的基因組中並保留下來。

When the protists were infected by giruses,

當這些原生生物被巨型病毒感染時，

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

牠們會利用該代碼自己製造出噬病毒體，從而接管巨型病毒的工廠。

In the end,

雖然最終，

the protist would still be killed by the girus infection,

原生生物仍會被巨型病毒的感染殺死，

but instead of releasing giruses to kill its buddies, 文法

但牠釋放的不再是去殺死同伴的巨型病毒，

it released virophages to hunt them.

而是去獵殺這些病毒的噬病毒體。

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

這個影片裡告訴你的一切，最奇妙的地方在於，我們仍處於探索的起步階段。

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

距離巨型病毒和噬病毒體被發現甚至還不到20年。

There is so much going on in the microverse.

在微觀世界中，還有太多未知的事情正在發生。

Life is not an isolated event, 慣用語

生命絕非孤立的事件，

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

而是萬億計的生物體和病毒之間的一場「乒乓球賽」。

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

所以，當你感到沮喪，覺得似乎沒什麼新事物可被發現時，

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

想想巨型病毒，以及我們周圍其他「大象般大小的鴨子」吧，

invisible until we look more closely. 表達脈絡

牠們只是隱形了，直到我們湊近仔細觀察才會顯現。