How we study the microbes living in your gut | Dan Knights

譯者: Lilian Chiu 審譯者: SF Huang

If I asked you to name a microbe that's living in your gut,

如果我請各位說出一種 住在你腸道中的微生物，

many of you would probably say E. coli.

許多人可能會說大腸桿菌。

A lot of people say this. It's the best-known of the gut microbes.

很多人會這麼說。 它是最多人知道的腸道微生物。

But it turns out that E. coli is outnumbered in your gut

但結果發現，在你的腸道中，

大腸桿菌的數量約只佔 腸道菌的千分之一，

about a thousand to one

by other species, many of which you probably haven't heard of.

而你可能沒有聽過其他這些 數量較多的菌種。

These are Bacteroides; Prevotella is another example.

像是擬桿菌或是普雷沃氏菌。

Those are the two that dominate the modern human gut.

這兩種菌種主宰了現代人的腸道。

There are about a hundred trillion microbes living inside you.

大約有一百兆微生物住在你體內。

We call this your microbiome,

我們稱之為你的微生物群系，

so it's like a little world living inside you --

它就像是個住在你體內的小世界——

actually more like a universe.

其實更像是個宇宙。

A hundred trillion means if you took a blade of grass

一百兆的大小概念是

如果ㄧ片葉片代表住在你 腸道內的每一個微生物，

and planted it for every microbe living in your gut,

that could fill a million football fields.

葉片可以填滿一百萬個足球場。

So it's incredibly complex.

所以它非常複雜。

But interestingly,

但有趣的是，

as our bodies have been adapting to life in modern society,

隨著我們的身體 適應現代社會的生活，

we're losing some of our normal microbes,

我們也失去了一些正常的微生物，

and at the same time,

且同時，

在全世界的已開發國家中，

there are quite a few diseases related to the gut

that are skyrocketing in developed nations all around the world.

有相當多腸道相關的疾病迅速竄升。

And many of you probably know someone who suffers from obesity,

在座許多人可能認識 有下列狀況的人：肥胖、

diabetes, Crohn's disease or ulcerative colitis,

糖尿病、克隆氏症或潰瘍性結腸炎、

allergies and asthma.

過敏及氣喘。

Every one of these diseases

所有這些疾病

and many others related to metabolism and autoimmunity

以及許多其他和新陳代謝 及自體免疫相關的疾病

are linked to a loss of healthy diversity in the gut.

都和腸道中失去了 健康多樣性的細菌有關。

My lab got our first indication of this

我的實驗室最初會發現這個現象，

when actually we were studying non-human primates.

其實是因為我們正在 研究非人類的靈長類。

We wanted to find out what happens to a monkey's microbiome

我們想要找出猴子 從叢林搬到動物園之後，

when they move from the jungle to a zoo.

牠們的微生物群系會發生什麼事。

牠們的微生物群系會改變嗎？ 牠們有得到新的菌種嗎？

Does their microbiome change? Do they pick up new bugs?

Do they lose some? Does it get better or worse?

還是牠們失去一些？ 這樣是好或不好？

We tracked two different species in the jungle,

我們在叢林中追蹤兩種不同的物種，

one in Vietnam, one in Costa Rica,

一種在越南，另一種在哥斯大黎加，

and then we sequenced the DNA from their stool.

我們從牠們的糞便 取得 DNA 來做定序。

This is how we study the microbiome in my research lab.

在我的研究實驗室中， 就是這樣研究微生物群系的。

And what we found in the DNA is that in the wild,

我們從 DNA 發現，

野外這兩個物種體內的 微生物群組完全不同。

these two species had totally different sets of microbes.

It was like a fingerprint for the species.

它就像是那些物種的指紋。

But in the zoo, they had lost most of that diversity

但在動物園中， 牠們的多樣性卻少了大半，

and had acquired some other set of microbes.

還取得了其他的微生物群組。

So this was very curious.

這非常讓人好奇。

We've got these two different microbiomes.

我們有這兩種不同的微生物群系。

In the wild, picture a lush tropical rainforest

想像一個蒼翠繁茂的熱帶雨林，

living the guts of these monkeys.

就居住在這些野外猴子的腸道中。

That's the kind of diversity that we're talking about.

我們在談的多樣性就類似這樣。

Then in the zoo, they've lost diversity.

而在動物園， 牠們就失去了多樣性。

Picture a rainforest that's been burned to the ground

想像一個被燒毀的雨林，

and taken over by a few invasive species.

只被幾種入侵的物種佔據。

That's more like the microbiome in a captive primate.

那就像是被關起來的 靈長類的微生物群系。

Now, in the meantime,

同時，

many of the animals in the zoo are not doing so well.

動物園中有許多動物的 狀況沒有很好。

They have issues with obesity,

牠們遇到的問題包括肥胖、

wasting,

消瘦、

gastroenteritis, diarrhea, bloating,

胃腸炎、腹瀉、脹氣，

and some of them were barely holding onto their lives.

有些動物幾乎無法活下去。

Now, of course, we were very interested to find out

當然，我們非常想要找出

what are these so-called invasive species that are taking over in the zoo.

在動物園中這些所謂的 入侵菌種到底是什麼。

So we went back to the DNA, and what the DNA told us

所以我們又回到 DNA， 而 DNA 告訴我們

is that every monkey in the zoo

動物園中的每一隻猴子

had become dominated by Bacteroides and Prevotella,

都被擬桿菌與普雷沃氏菌所主宰，

the same microbes that we all have in our guts as modern humans.

我們現代人的腸道中 也都有同樣的這些微生物。

We wanted to find a way to visualize this,

我們想以圖像呈現出這個結果，

and we used some tools from multivariate ecology

所以我們用了一些 多變量生態學的工具，

to put all of the microbiomes we were studying onto an axis.

把所有我們在研究的 微生物群系放到一個軸上。

And what you're seeing here is a distance plot

各位現在看見的是一張距離圖，

where every point is a different animal's microbiome.

圖上的每一點代表著 不同動物的微生物群系。

So every point represents a whole zoo of microbes.

所以每一個點都代表 整個動物園的微生物。

And the microbiomes that have a lot of microbes in common

微生物越相似的微生物群系，

are close to each other.

它們在圖上的距離就會越接近彼此。

The ones that are very different are farther apart.

反之，則會離越遠。

So this is showing you

這張圖是要讓各位看看

that the two groups of wild monkeys are over on the left.

兩群野生猴子的點都落在圖的左側。

The top left are these highly endangered monkeys

左上角是嚴重瀕臨絕種的猴子，

called the red-shanked douc in Vietnam.

是越南的白臀葉猴。

And at the bottom left are monkeys from Costa Rica.

左下角則是在哥斯大黎加的猴子。

So you can see that they have totally different microbiomes in the wild.

各位可以看見，野外的猴子 有著迥然不同的微生物群系。

And then the same two species of monkey in the zoo are converging,

而同樣是這兩種猴子， 在放入動物園後卻變得很相似，

so their microbiomes change

所以牠們的微生物群系會變，

and they become much more similar to each other,

彼此變得更相似，

even though these are zoos on different continents,

即使牠們所屬的動物園 位在不同的大陸，

different geographical regions, and they're eating different diets.

不同的地理區， 牠們還吃不同的食物。

Now, we did study some other species of primate.

我們的確也研究了其他靈長類物種。

What species of primate do you think is even more divergent

你們認為哪種靈長類的差異性

比起動物園和野生靈長類的 差異性更大？

from the wild primates than the captive primates?

Modern humans.

現代人類。

These are humans living in developing nations.

這些是住在開發中國家的人。

So they were more different from the wild primates

和在動物園中的靈長類相比，

他們和野生靈長類的差異更大。

than those in the zoo.

And the final group that we studied, all the way on the right,

我們研究的最後一個族群， 在圖的最右邊，

is people living in the USA.

就是住在美國的人。

And when I saw this figure,

當我看到這張圖，

the hairs raised up on the back of my neck,

讓我寒毛直豎，

because one way to think about it is, "Oh, that's interesting,

因為對這現象的一種思考方式是： 「喔，好有趣，

captive monkeys are sort of on their way to becoming like Americans."

被關起來的猴子漸漸 變得和美國人一樣了。」

(Laughter)

（笑聲）

But the other way to think about it

但另一種思考方式是

is that Americans are like super-captive monkeys.

美國人就像是被關過頭的猴子。

And I was actually looking at this figure on my computer screen

當我在我的電腦螢幕上 看著這張圖時，

when I got the news that four of the red-shanked doucs

我聽到一個消息， 動物園中有四隻白臀葉猴

had died in the zoo of gut-related issues.

死於腸道相關疾病。

So for some of these animals,

所以對這些動物園的動物而言，

having the right microbes living inside them

體內是否有對的微生物，

may be a matter of survival.

可能是生死攸關的事。

Now this brings us to the human part of the story.

所以接下來就要談到 關於人類的部分了。

Obviously, the microbiomes in the USA

很顯然，在美國的微生物群系

aren't causing premature death as frequently as in the zoo,

所造成的過早死亡， 並沒有動物園中那麼頻繁，

but we have major risk of obesity, diabetes,

但我們有很大的風險， 可能會產生肥胖、糖尿病，

a number of these other diseases.

以及許多其他這類疾病。

And this applies not just to people who have been living in the USA

這不僅適用於已經在美國

住了數個世代的人，

for many generations,

but also to immigrants and refugees,

也適用於移民和難民，

who, for most immigrant and refugee groups,

大部分的移民和難民族群

arrive in the USA metabolically healthy,

在抵達美國時， 新陳代謝是很健康的，

and then within a few years,

然而短短幾年後，

they become just as high-risk for obesity and diabetes

他們卻變成和美國人一樣，

有很高的肥胖和糖尿病風險。

as other Americans.

And we discussed this issue with two groups

我們和兩個族群討論了這個議題，

that have been coming to the USA from Southeast Asia:

他們是從東南亞來到美國的：

the Hmong, who started coming in the mid-1970s

赫蒙族，他們從七○年代中期

as refugees from the Vietnam War and the US secret war in Laos;

就以越戰與美寮秘密戰爭的 難民身分來到美國；

and the Karen, who have been coming more recently as refugees from Myanmar.

還有克倫族，他們是比較近期 才以緬甸難民的身份到美國。

So we've been working for a few years

我們花了幾年的時間，

with these local communities and clinicians

和當地的社區和臨床醫生合作，

to study what happens to the Hmong and Karen microbiomes

研究赫蒙族和克倫族從難民營 和泰國的村落搬到美國之後，

when people move from refugee camps and villages in Thailand to the USA.

他們的微生物群系產生了什麼變化。

And what we found

我們發現

is that when people come to the USA from these groups,

當這些族群的人來到美國，

they lose a large fraction of their microbiome,

他們失去了很多的微生物群系，

somewhere around 20 percent,

大約 20% 上下，

and those who come to the USA and become obese

而到了美國且變肥胖的人，

lose about a third of their microbes.

少了大約三分之一的微生物。

So we know that moving to the USA

所以，我們知道搬到美國

is sufficient to cause a dramatic change in your microbiome,

就足以造成微生物群系的巨大改變，

probably not for the better.

且可能不是變好。

Are these microbes actually causing the obesity,

真的是這些微生物造成了肥胖？

or is the obesity causing a change in the microbes?

還是肥胖造成了微生物的改變？

This is something that we're following up on,

我們後續還在追蹤探究，

and the evidence we have now in my lab

而將我實驗室中得到的證據

combined with evidence from a number of labs around the world

和來自世界各地的實驗室 所發現的證據彙整後，

tells us that certain changes in the microbiome

顯示了微生物群系的某些改變

do lead to obesity,

的確會導致肥胖

and a number of other modern, kind of Westernized diseases.

以及其他數種現代西化的疾病。

The good news is that your microbiome can actually change.

好消息是你的微生物群系 可以被改變。

Unlike your own genome,

不像你自己的基因組，

it's a living, breathing thing,

它是活的、會呼吸的生物，

and there's a broad front of research happening right now

且現有廣泛大量的研究正在進行，

讓我們更明瞭當我們的 微生物群系發生問題時，

to better understand how we can restore our microbiomes

when something goes wrong,

我們要如何

using diet,

透過飲食、

using live microbes.

透過活的微生物來恢復。

And in fact, one of the next steps for us

事實上，我們接下來的其中一步，

is collecting and preserving microbes from healthy people around the world

就是要收集和保存來自 全世界健康人類的微生物，

so that they can be kept as cultural assets for those groups

將其作為這些族群的文化資產 而予保存下來，

to potentially protect them as they adapt to modern society,

在族群適應現代社會的過程中 提供所需的保護，

and to protect future generations

也可以保護未來的世代，

who are currently growing up to have increased risk of these diseases

這些世代目前成長的過程中， 得到這些疾病的風險越來越高，

with every generation.

一代比一代高。

I'm looking forward to a future

我很期待看到在未來

where we have the tools that we need to restore and replenish our microbiomes,

我們會有所需的工具 來恢復和補充我們的微生物群系，

and in that world, the monkeys will live happier and healthier lives,

在那個世界中，猴子能過著 比較快樂、健康的生活，

and so will we.

我們也一樣。

(Applause)

（掌聲）