Name: 為什麼微生物照射到紫外線會爆炸?（Why Do Microbes Explode Under UV Light?）
Uploaded: 2022-09-02T16:01:43.000Z
Duration: 10 min 58 s

This episode is sponsored by Wren, a website where you calculate your carbon footprint.

本集由Wren贊助，這是一個計算你的碳足跡的網站。

You can also sign up to make a monthly contribution to offset your carbon footprint or support

你也可以註冊後每月捐款，以抵消你的碳足跡或支持

Blepharisma have appeared on our channel several times before.

Blepharisma以前曾多次出現在我們的頻道上。

In fact, this channel got its start thanks to a video that James, our master of microscopes,

事實上，這個頻道的開始要歸功於我們的顯微鏡大師詹姆斯的一段視頻。

曾經發布過一個Blepharisma死亡的消息。

Around 3 million people watched that video, including me, your host Hank Green.

大約有300萬人觀看了該視頻，包括我，你們的主持人漢克-格林。

So if you enjoy this channel, you can thank that dead Blepharisma.

是以，如果你喜歡這個頻道，你可以感謝那個死去的Blepharisma。

But perhaps you should wait for another day to thank them.

但也許你應該等待另一天來感謝他們。

Because in about 10 seconds, you're going to watch a Blepharisma explode.

因為在大約10秒鐘內，你將看到一個Blepharisma爆炸。

Here it is, glowing with autofluorescence underneath UV light.

在這裡，它在紫外光下發出自發熒光。

You can see its oblong shape and oral groove outlined in red…but not for long.

你可以看到它的長方形形狀和用紅色勾勒出的口腔溝槽......但時間不長。

The red becomes brighter and brighter, but it also looks like it's starting to expand.

紅色變得越來越亮，但它看起來也開始膨脹了。

And then suddenly, the walls of the blepharisma burst, the organism popping like a crimson balloon.

然後突然間，瞼板腺壁破裂，生物體像一個深紅色的氣球一樣爆裂。

The blepharisma bubbles and pours into its surroundings and it all happens within a matter

漂浮物冒出氣泡並湧入其周圍環境，這一切都發生在事後。

Dead or dying microbes are a common enough sight in our journey through the microcosmos.

在我們的微觀世界的旅程中，死亡或垂死的微生物是一個足夠常見的景象。

And there are many potential culprits behind these deaths: predators, accidents, environmental

而這些死亡背後有許多潛在的罪魁禍首：捕食者、事故、環境因素。

changes, the inevitable march of life into death.

變化，生命不可避免地走向死亡。

But the culprit this time… well, it was us.

但這次的罪魁禍首......嗯，是我們。

Us and the UV light that is part of our new fluorescence microscope upgrade.

我們和紫外光是我們新的熒光顯微鏡升級的一部分。

And our UV light has been very exciting for us.

而我們的紫外光對我們來說是非常令人興奮的。

In particular, it's allowed us to look for methanogens, or Archaea, which sometimes take

特別是，它使我們能夠尋找甲烷菌，或稱古細菌，它們有時會採取

Under normal light, it's hard to tell the tiny archaea and the tiny bacteria apart.

在正常光線下，很難將微小的古細菌和微小的細菌區分開來。

But under UV light, the archaea will shine blue.

但在紫外光下，古細菌會發出藍色的光芒。

So UV can reveal new aspects of the microcosmos.

是以，紫外線可以揭示出微觀世界的新方面。

But if you've ever fallen asleep on a beach or just stayed out in the sun a bit too long,

但是，如果你曾經在海灘上睡著了，或者只是在陽光下呆得有點久。

you may have also experienced the darker side of UV light.

你可能也經歷過紫外線的黑暗面。

No one wants a sunburn, but fortunately, we have defenses, like hair, and melanin, and

沒有人希望被晒傷，但幸運的是，我們有防禦措施，如頭髮和黑色素，以及

sunscreen which can block or absorb UV rays before they cause further damage in our cells.

防晒霜可以在紫外線對我們的細胞造成進一步損害之前阻擋或吸收它們。

We also, and this is crucial, have more than one cell...so if some of them die, which when

我們還有，這一點很關鍵，我們有不止一個細胞......所以，如果其中一些細胞死亡，這時

you get a sunburn they do, the rest of our bodies can live on.

你被晒傷了，他們會這樣做，我們身體的其他部分可以繼續生存。

Not all organisms have these sorts of protections.

並非所有的生物體都有這類保護措施。

Or if they do, they're designed for exposure to the sun, not the intense scrutiny of our UV light.

或者，如果他們這樣做，他們是為暴露在陽光下而設計的，而不是我們的紫外線的強烈審查。

So when James wants to hunt Archaea, he has to be careful.

是以，當詹姆斯想要獵殺阿蓋爾時，他必須要小心翼翼。

He can quickly shine the UV light to see if anything blue appears.

他可以迅速用紫外光照射，看看是否有藍色的東西出現。

Because as we've seen, even a few seconds of exposure to the UV light will kill off

因為正如我們所看到的，即使暴露在紫外線下幾秒鐘也會殺死

We want to note that as we said earlier, death is a common reality of the microcosmos…we

我們要注意的是，正如我們前面所說，死亡是微觀世界的一個共同現實......我們

just usually prefer to walk in on a microbe dying rather than being the cause of death.

只是通常更願意走進微生物的死亡，而不是成為死亡的原因。

But for this episode, we decided to make an exception and use our UV light for an extended

但在這期節目中，我們決定破例使用我們的紫外線燈，以延長

period of time, with the knowledge that it would kill the microbe we were watching.

一段時間後，知道它將殺死我們正在觀察的微生物。

Because these explosions illustrate the cost of doing business with light.

因為這些爆炸事件說明了與光合作用的代價。

The word for this business is phototoxicity.

And while it can happen under other monochromatic lights, the particular wavelength and intensity

雖然在其他單色光下也會發生這種情況，但特定的波長和強度

of our UV light makes it much more harmful to our organisms than our other red, blue,

的紫外線使其對我們的生物體的危害比我們的其他紅色、藍色要大得多。

When the light hits the organism, it can potentially excite chemical structures inside the cell,

當光線照射到生物體上時，它有可能激發細胞內的化學結構。

sending electrons up and down, and producing fluorescent colors in the process.

向上和向下發送電子，並在此過程中產生熒光色。

But colors aren't the only thing that gets created.

但是顏色並不是唯一被創造的東西。

If there's oxygen around, it will react with the excited fluorescent molecule, creating

如果周圍有氧氣，它將與被激發的熒光分子發生反應，產生

what are known as reactive oxygen species.

In biology, reactive oxygen species are byproducts of different cellular processes that metabolize

在生物學中，活性氧是不同細胞過程中的副產品，它可以代謝

oxygen, which can make them part of normal life.

氧氣，這可以使它們成為正常生活的一部分。

There are even reactive oxygen species that are involved in signaling pathways.

甚至還有參與信號傳導途徑的活性氧。

But the “reactive” in their name is key to what makes an excess amount of them dangerous.

但是它們名稱中的 "反應性 "是使過量的它們變得危險的關鍵所在。

If you are an organism, and you are, there are a lot of reactions you want to have happen

如果你是一個有機體，而你確實是，有很多你想發生的反應

You want your DNA to link together correctly, you want your enzymes to find the right substrates.

你希望你的DNA能正確地連接在一起，你希望你的酶能找到正確的底物。

But reactive oxygen species are happy to react with all of those molecules too, damaging

但活性氧也樂於與所有這些分子發生反應，破壞了

them and getting in the way of the chemistry that we need to survive.

他們並妨礙了我們生存所需的化學反應。

What phototoxicity will look like depends on the organism and the light being directed at it.

光毒性是什麼樣子的，取決於生物體和被照射的光線。

For the organisms we've been showing here, like this homalozoon, the overall effect of

對於我們在這裡展示的生物體，如這個同形蟲，其總體效果是

this intense UV light seems to be unanimous: the cell swells up and bursts open, like a

這種強烈的紫外線似乎是一致的：細胞膨脹並爆裂開來，像一個

銀河系在我們的滑梯上爆發了。

But while the overall effect is the same, the internal machinations are likely different,

但是，雖然整體效果是一樣的，但內部的陰謀詭計可能是不同的。

triggered by a complex interplay of different chemicals that nonetheless react to our light

由不同化學品的複雜相互作用引發，但這些化學品對我們的光線有反應。

source in a similar, catastrophic fashion.

在一個類似的、災難性的方式中的來源。

While we're not sure of the culprits behind the homalozoon's death, we can identify

雖然我們不確定這名同性戀者死亡背後的罪魁禍首，但我們可以確定

one of the chemicals that likely sets off the blepharisma's death.

其中一種化學物質很可能引發出血性疾病的死亡。

It's the reddish pigment molecule called blepharismin that gives the ciliate its color

是名為blepharismin的紅色色素分子賦予了纖毛蟲顏色。

Outside of the UV light, you can see the membrane-bound pigments neatly distributed along the rows

在紫外光的照射下，你可以看到膜結合的色素整齊地分佈在一排排。

that stretch from one end of the blepharisma to the other.

從瞼板腺的一端延伸到另一端。

But under our UV light and with oxygen in the environment, the blepharismin reacts to

但在我們的紫外線下和環境中的氧氣，漂白素會反應成

form reactive oxygen species, and death follows quickly from there.

形成活性氧，死亡很快就從這裡開始。

But while toxic in our experiment, we should note that the blepharismin serves a key purpose

但在我們的實驗中，雖然有毒，但我們應該注意到，瞼板腺素有一個關鍵的用途

These pigment molecules are toxic to some of Blepharisma's predators in both the light and the dark.

這些色素分子在明處和暗處都對漂白蟲的一些捕食者有毒。

That makes the pigment somewhat like UV light: necessary for survival, yet also a delicate negotiation.

這使得色素有點像紫外線：生存所需，但也是一種微妙的談判。

But in the same way that we manage our relationship with the sun, scientists have learned ways

但是，就像我們處理與太陽的關係一樣，科學家已經學會了一些方法

They've had to in order to understand how we can use fluorescence microscopy to study

他們不得不這樣做，以瞭解我們如何使用熒光顯微鏡來研究

They've learned how to modulate wavelength and intensity and duration, along with many

他們已經學會了如何調控波長、強度和持續時間，以及許多

other factors, to wield light in a way that better serves their purposes.

其他因素，以更好地服務於他們的目的的方式來揮舞光。

In the case of the blepharisma, for example, scientists found that using a moderate light

以瞼板腺為例，科學家們發現，使用適度的光線

for around 1 hour wasn't much of a problem for them.

對他們來說，1小時左右的時間並不是什麼問題。

But with more time under the light, the cells would eventually die.

但隨著在燈光下的時間增加，細胞最終會死亡。

It's easy to think of the microcosmos as a separate world from us, even when we know

我們很容易認為微觀世界是一個與我們分離的世界，即使我們知道

that the microscope is a bridge between large and small.

顯微鏡是連接大型和小型的橋樑。

But these deaths at the hand of our supposed bridge are a cautionary sign that we are encountering

但這些死於我們所謂的橋樑之手，是一個警告性的信號，我們正在遇到

microbes in a world that is both natural and manufactured at the same time.

微生物在一個既是自然的又是人造的世界裡。

The way that we light that world impacts the way we see the organisms, and it also shapes

我們照亮這個世界的方式影響著我們看待生物的方式，它也塑造了

their lives—reminding us that they are stronger often than we can fathom, but fragile nonetheless.

他們的生活--提醒我們，他們往往比我們所能想象的更強大，但還是很脆弱。