17:29
TED2014

Rob Knight: How our microbes make us who we are

ロブ・ナイト: 微生物がどのようにして私達を作っているのか

Filmed:

ロブ・ナイトは、人体内の微生物研究におけるパイオニアです。私達の体内に宿る小さな単細胞生物群は、私達の健康において、極めて大きな役割を担っています。そして、この分野は未だに良く知られていません。「私達が体内に抱えている3ポンドの微生物は、ゲノム内のどの遺伝子よりも重要かもしれません」と言う、その彼の理由を聴いてみましょう。

- Microbial ecologist
Rob Knight explores the unseen microbial world that exists literally right under our noses -- and everywhere else on (and in) our bodies. Full bio

We humans have always been very concerned
about the health of our bodies,
誰でも常に健康に関心がありますが
00:13
but we haven't always been that good
at figuring out what's important.
今まで必ずしも何が大切なのか
理解していたとは限りません
00:17
Take the ancient Egyptians, for example:
例えば古代エジプトを見ると
00:21
very concerned about the body parts
they thought they'd need in the afterlife,
死後の世界に必要だと思われた
体の部分はとても大事に扱われ
00:23
but they left some parts out.
その一方ある部分は除外されました
00:27
This part, for example.
つまり
00:29
Although they very carefully
preserved the stomach, the lungs,
胃 肺 肝臓などは
00:32
the liver, and so forth,
注意深く保存されましたが
00:35
they just mushed up the brain,
drained it out through the nose,
脳は潰され鼻から抽出され
00:36
and threw it away,
捨てられていました
00:39
which makes sense, really,
確かに
00:41
because what does a brain
do for us anyway?
脳は一体何の役に立つと言うのでしょう
00:42
But imagine if there were a kind
of neglected organ in our bodies
しかし脳程の重さで
我々自身ともいえる
00:45
that weighed just as much as the brain
重要な臓器が我々の体に
00:48
and in some ways was just
as important to who we are,
他にあるでしょうか
00:50
but we knew so little about
and treated with such disregard.
なのに 知られている事も関心も
殆どありませんでした
00:53
And imagine if,
through new scientific advances,
しかし新しい科学の進歩で
00:57
we were just beginning to understand
ヒトの理解に役立つ
01:00
its importance to how
we think of ourselves.
重要な事柄が
分かり始めて来たばかりだとしたら
01:01
Wouldn't you want to know more about it?
もっと それについて
知りたいと思いませんか
01:04
Well, it turns out that we do
have something just like that:
実はその脳に似た物が
他にもあるのです
01:07
our gut,
我々の腸です
01:10
or rather, its microbes.
腸内の微生物と
言った方がいいでしょう
01:12
But it's not just the microbes
in our gut that are important.
でも大切なのは
腸内微生物だけではありません
01:15
Microbes all over our body
体内外の微生物が
01:18
turn out to be really critical
to a whole range of differences
広範囲に渡り影響を及ぼし
大きく健康を左右していることが
01:19
that make different people who we are.
分かってきました
01:22
So for example, have you ever noticed
その例として
01:25
how some people get bitten by mosquitos
way more often than others?
蚊に刺され易い人がいる事に
気付かれた事がありますか
01:27
It turns out that everyone's anecdotal
experience out camping is actually true.
誰でも同じような経験がキャンプでありますね
01:31
For example, I seldom
get bitten by mosquitos,
私自身あまり蚊に刺される事はありませんが
01:36
but my partner Amanda
attracts them in droves,
私の妻アマンダには蚊の大群が寄ってきます
01:38
and the reason why is that we have
different microbes on our skin
その理由は人それぞれ
皮膚には異なる微生物が
01:41
that produce different chemicals
that the mosquitos detect.
固有の化学物質を
分泌しているからです
01:44
Now, microbes are also really important
in the field of medicine.
微生物は医療の分野でも とても重要です
01:48
So, for example, what microbes
you have in your gut
一例として腸内微生物は
01:51
determine whether particular painkillers
are toxic to your liver.
肝臓に対し毒性を持つ鎮痛剤や
01:54
They also determine whether or not other
drugs will work for your heart condition.
心臓病に効く薬を判断します
01:58
And, if you're a fruit fly, at least,
そして あなたがミバエなら
02:02
your microbes determine
who you want to have sex with.
あなたのパートナーは
あなたの微生物に決められます
02:05
We haven't demonstrated this in humans yet
これはヒトでは検証されていませんが
02:08
but maybe it's just a matter of time
before we find out. (Laughter)
それが分かるのは時間の問題でしょう
(笑)
02:10
So microbes are performing
a huge range of functions.
このように微生物は
広範囲に渡り活動しています
02:15
They help us digest our food.
食物を消化したり
02:17
They help educate our immune system.
免疫系に働きかけ
02:19
They help us resist disease,
病気に対抗したりし
02:21
and they may even
be affecting our behavior.
また我々の行動にさえも影響を及ぼします
02:23
So what would a map of all these
microbial communities look like?
では微生物叢(そう)の分布図とは
どんなものでしょうか
02:26
Well, it wouldn't look exactly like this,
全くこれと同じではないでしょうが
02:30
but it's a helpful guide
for understanding biodiversity.
生物学的多様性を理解するには
助けとなる手段となります
02:32
Different parts of the world
have different landscapes of organisms
固有の様態をした有機体が
02:35
that are immediately characteristic
of one place or another
世界中その土地土地にいて
それが直接その地の
02:39
or another.
特性となります
02:43
With microbiology, it's kind of the same,
although I've got to be honest with you:
微生物学でも同じ様な事が言えますが
02:45
All the microbes essentially
look the same under a microscope.
正直言って 顕微鏡の下では
微生物は本質的に皆似ているので
02:49
So instead of trying
to identify them visually,
様相から識別するのでなく
02:52
what we do is we look
at their DNA sequences,
ヒト微生物のDNA配列を
02:55
and in a project called
the Human Microbiome Project,
ヒト微生物叢プロジェクト
と呼ばれるプロジェクトで
02:57
NIH funded this $173 million project
NIHから1億7300万ドルの
支援を受け研究しています
03:00
where hundreds
of researchers came together
何百人もの研究者が集まり
03:04
to map out all the A's, T's, G's, and C's,
ヒト微生物全ての
03:06
and all of these microbes
in the human body.
ATGC配列を読み取り
03:09
So when we take them together,
they look like this.
集めて見てみるとこんな感じです
03:11
It's a bit more difficult
to tell who lives where now, isn't it?
どれがどれだか
ちょっと見分けがつきませんね
03:14
What my lab does is develop
computational techniques that allow us
我々が開発した計算技法で
03:18
to take all these terabytes
of sequence data
テラバイトの配列データ全てを
03:22
and turn them into something
that's a bit more useful as a map,
マップとしてもっとよく使える様にし
03:24
and so when we do that
with the human microbiome data
250人の健康なボランティアから採った
03:27
from 250 healthy volunteers,
ヒト微生物叢のデータを用い作ったものが
03:30
it looks like this.
この様になります
03:32
Each point here represents
all the complex microbes
図の一点ずつが複雑な微生物の集合体
03:35
in an entire microbial community.
微生物叢を表します
03:38
See, I told you they basically
all look the same.
言った通り どれも似ているでしょう
03:40
So what we're looking at is each point
represents one microbial community
1つの点が 健康な人体の1カ所から採取された
03:43
from one body site
of one healthy volunteer.
微生物叢を表しています
03:46
And so you can see that there's different
parts of the map in different colors,
様々な色がその箇所毎に個々の大陸を作って
03:49
almost like separate continents.
地図を作っているかの様です
03:53
And what it turns out to be
これで分かることは
03:54
is that those, as the different
regions of the body,
体の箇所により非常に
03:56
have very different microbes in them.
微生物叢が異なるという事です
03:58
So what we have is we have
the oral community up there in green.
緑色は口腔の
04:00
Over on the other side,
we have the skin community in blue,
その反対側の青色は皮膚の
04:04
the vaginal community in purple,
紫色は膣内の
04:07
and then right down at the bottom,
we have the fecal community in brown.
そして下の茶色の塊は
糞便の微生物叢を表しています
04:09
And we've just over the last few years
そしてこの数年
04:13
found out that the microbes
in different parts of the body
体の部分により
微生物叢には信じられない程の
04:15
are amazingly different from one another.
多様性がある事が分かりました
04:18
So if I look at just one person's microbes
たった1人の口や腸内の
04:20
in the mouth and in the gut,
微生物を見ただけでも
04:23
it turns out that the difference between
those two microbial communities
その2組の微生物叢の違いは
04:25
is enormous.
とてつもなく
04:28
It's bigger than the difference
between the microbes in this reef
この珊瑚礁と草原の微生物叢の違いより
04:30
and the microbes in this prairie.
著しいのです
04:33
So this is incredible
when you think about it.
そう考えると すごい事なんです
04:36
What it means is that a few feet
of difference in the human body
60センチ離れただけで人体の
微生物生態系は大きく変わり
04:38
makes more of a difference
to your microbial ecology
その相違は地球上何千キロ行っても
04:42
than hundreds of miles on Earth.
あり得ない程の膨大さなのです
04:44
And this is not to say that two people
look basically the same
そして 同じヒトだからといって
我々の微生物の生態系は
04:46
in the same body habitat, either.
皆同じだという訳ではありません
04:49
So you probably heard
多分ご存知だと思いますが
04:51
that we're pretty much all the same
in terms of our human DNA.
遺伝子学的に言って
私たちは皆似ています
04:53
You're 99.99 percent identical
in terms of your human DNA
ヒトDNAから見ると私たちは99.9%
04:56
to the person sitting next to you.
隣にいる人と同じですが
05:00
But that's not true of your gut microbes:
微生物学的にはそうではなく
05:02
you might only share 10 percent similarity
隣に座っている人とあなたは
05:04
with the person sitting next to you
in terms of your gut microbes.
同じ微生物を10%共有するかしないかです
05:07
So that's as different
as the bacteria on this prairie
それが この草原や森のバクテリアと
05:10
and the bacteria in this forest.
ヒトのそれとの違いです
05:13
So these different microbes
この違いが
05:16
have all these different kinds
of functions that I told you about,
今話した様な種々の機能—
05:17
everything from digesting food
食物の消化から
05:21
to involvement
in different kinds of diseases,
あらゆる病気や薬物の代謝—
05:22
metabolizing drugs, and so forth.
などに関与してきます
05:25
So how do they do all this stuff?
どうして 微生物にこんな事が
できるのでしょう?
05:27
Well, in part it's because
その理由の一部は
05:29
although there's just three pounds
of those microbes in our gut,
私たちのお腹にいる
1.4キロ程の微生物の数が
05:31
they really outnumber us.
人の数を凌いでいるからです
05:34
And so how much do they outnumber us?
どれ程人を凌いでいるかと言うと
05:36
Well, it depends on what
you think of as our bodies.
比較するには地球上の人口では間に合いません
05:38
Is it our cells?
細胞と比べてはどうでしょう
05:41
Well, each of us consists
of about 10 trillion human cells,
人体は約10兆程のヒト細胞で成っていますが
05:43
but we harbor as many
as 100 trillion microbial cells.
宿している微生物細胞の数は100兆で
05:46
So they outnumber us 10 to one.
ヒト細胞数の10倍です
05:49
Now, you might think, well,
we're human because of our DNA,
「でもヒトはDNAで決まるのだから」
と思われるでしょうが
05:52
but it turns out that each of us has
about 20,000 human genes,
1人に約2万の遺伝子がある事が
分かっています—
05:56
depending on what you count exactly,
正確に何を数えるかにも依りますが—
05:59
but as many as two million
to 20 million microbial genes.
しかし微生物遺伝子は2百万から2千万です
06:01
So whichever way we look at it,
we're vastly outnumbered
どちらを向いても共生微生物達の数には
06:06
by our microbial symbionts.
とうてい敵いっこありません
06:08
And it turns out that in addition
to traces of our human DNA,
そして私たちが触るもの全てに
ヒトDNAだけでなく
06:11
we also leave traces
of our microbial DNA
微生物のDNAまでをも我々は
06:15
on everything we touch.
後に残すことが分かっています
06:17
We showed in a study a few years ago
数年前の我々の研究で
06:19
that you can actually match
the palm of someone's hand up
コンピュータのマウスと
それを使う人の手のひらの
06:20
to the computer mouse
that they use routinely
微生物が95%までの正確さで
06:23
with up to 95 percent accuracy.
マッチしました
06:25
So this came out in a scientific journal
a few years ago,
これは数年前 科学誌に発表されましたが
06:28
but more importantly,
it was featured on "CSI: Miami,"
それより重要な『CSI: マイアミ』に
採用されたので
06:31
so you really know it's true.
これで信じてもらえるでしょう
06:33
(Laughter)
(笑)
06:35
So where do our microbes
come from in the first place?
そもそも我々の微生物は
どこから来るのでしょう
06:36
Well if, as I do, you have dogs or kids,
犬も子供もいる方は—
私には両方いますが—
06:40
you probably have
some dark suspicions about that,
多分 「もしかしたら」
と思っていらっしゃるでしょう
06:43
all of which are true, by the way.
実は全くその通りでなのです
06:45
So just like we can match
you to your computer equipment
コンピュータとそれを使う人の微生物が
06:47
by the microbes you share,
マッチするだけでなく
06:50
we can also match you up to your dog.
犬と飼い主の微生物もマッチします
06:51
But it turns out that in adults,
しかし成人の微生物は比較的
06:54
microbial communities
are relatively stable,
変動しない事が分かっているので
06:56
so even if you live together with someone,
誰かと共同生活をしても
06:58
you'll maintain your separate
microbial identity
成人は固有の微生物を
07:00
over a period of weeks,
months, even years.
何週間も時には何年も持ち続けます
07:02
It turns out that our
first microbial communities
初期のヒトの微生物叢は
出産で大きく差が出る
07:05
depend a lot on how we're born.
という事も分かっています
07:08
So babies that come out
the regular way,
普通分娩で産まれた赤ちゃんは
07:11
all of their microbes are basically
like the vaginal community,
基本的に母親の膣内微生物叢を持ち
07:13
whereas babies that are
delivered by C-section,
一方 帝王切開で産まれた赤ちゃんの
07:16
all of their microbes instead
look like skin.
微生物は全て皮膚常在菌となります
07:18
And this might be associated
with some of the differences
帝王切開で産まれた人は
07:21
in health associated with Cesarean birth,
微生物との関わりがある
07:24
such as more asthma, more allergies,
even more obesity,
嘆息 アレルギーそして肥満さえも
普通分娩の人より罹り易く
07:27
all of which have been linked
to microbes now,
出産と健康との関係が
考えられています
07:30
and when you think about it,
until recently, every surviving mammal
思えば ごく最近まで ほ乳類は
07:33
had been delivered by the birth canal,
全て自然分娩でした
07:37
and so the lack
of those protective microbes
我々と共進化して来た
07:39
that we've co-evolved with
might be really important
保護的微生物がないという事は
07:41
for a lot of these different conditions
that we now know involve the microbiome.
微生物が関わる健康問題には
本当に重大な事かもしれません
07:44
When my own daughter was born
a couple of years ago
数年前 私の娘が産まれた時
07:48
by emergency C-section,
緊急の帝王切開でしたが
07:51
we took matters into our own hands
私と妻は自分たちで
07:53
and made sure she was coated
with those vaginal microbes
普通分娩の様に娘が母体の膣内常在菌に
07:55
that she would have gotten naturally.
覆われる様にしました
07:58
Now, it's really difficult to tell
whether this has had an effect
さあ これが娘の健康に
どんな効果があったのか
08:00
on her health specifically, right?
全く分かりませんが
08:03
With a sample size of just one child,
no matter how much we love her,
どれ程の愛情を持ってしても
たった1人の子供からだけのサンプルサイズでは
08:05
you don't really have
enough of a sample size
一般的データを得るには
08:09
to figure out what happens on average,
十分ではありません
08:11
but at two years old,
she hasn't had an ear infection yet,
この2年間 娘は耳感染症に
罹った事はありません
08:13
so we're keeping our fingers
crossed on that one.
これからも何もない事を祈っています
08:16
And what's more, we're starting
to do clinical trials with more children
さらに子供たちを使って
微生物に保護的な効果が
08:18
to figure out whether
this has a protective effect generally.
一様にあるものかどうか
臨床研究を始めました
08:22
So how we're born has a tremendous effect
on what microbes we have initially,
出産方法が大きく影響し
最初の微生物生態系が決まります
08:27
but where do we go after that?
では この後どうなるのでしょう?
08:32
What I'm showing you
again here is this map
ヒト微生物プロジェクトのデータ分布図を
08:34
of the Human Microbiome Project Data,
もう一度ご覧ください
08:36
so each point represents
a sample from one body site
点が一人の体の一部から採った微生物叢を表し
08:38
from one of 250 healthy adults.
全部で250人からの物です
08:41
And you've seen children
develop physically.
子供の身体的成長や
08:43
You've seen them develop mentally.
精神的成長は目にできたとしても
08:45
Now, for the first time,
you're going to see
これは初めてご覧になる物でしょう
08:47
one of my colleague's children
develop microbially.
ある同僚の子供の微生物学的成長です
08:50
So what we are going to look at
今からご覧になるのは
08:53
is we're going to look
at this one baby's stool,
ある赤ちゃんの便からの物で
08:54
the fecal community,
which represents the gut,
腸内細菌叢を代表するものです
08:57
sampled every week
for almost two and a half years.
2年半近く 毎週試料を採取しました
09:00
And so we're starting on day one.
1日目から始めました
09:03
What's going to happen is that the infant
is going to start off as this yellow dot,
嬰児はまず最初に黄色い粒
09:04
and you can see that he's starting off
basically in the vaginal community,
膣内微生物叢から始まります
09:08
as we would expect from his delivery mode.
自然分娩から当然期待される事ですね
09:12
And what's going to happen
over these two and a half years
2年半の間で
09:14
is that he's going to travel
all the way down
この子の微生物叢は
09:17
to resemble the adult fecal community from
healthy volunteers down at the bottom.
健康な成人の糞便微生物叢に似通ってきます
09:19
So I'm just going to start this going
and we'll see how that happens.
始めますので どうなるか見て下さい
09:23
What you can see, and remember
each step in this is just one week,
見ているのは1週間に1ステップです
09:26
what you can see is that week to week,
週毎に
09:30
the change in the microbial community
of the feces of this one child,
子供の糞便微生物叢の変化が見られ
09:32
the differences week to week
are much greater
その週毎の変化は
ヒト微生物プロジェクトが行った
09:37
than the differences between
individual healthy adults
コホートの健康な成人と比べると
09:40
in the Human Microbiome Project cohort,
ずっと大きいのです
09:42
which are those brown dots
down at the bottom.
その成人の微生物叢は
下の茶色の物です
09:44
And you can see he's starting
to approach the adult fecal community.
ご覧の様に成人の便のそれに
近くなっているのが見れますね
09:47
This is up to about two years.
これが約2年程続き
09:50
But something amazing
is about to happen here.
ここでとても驚くことが起きます
09:51
So he's getting antibiotics
for an ear infection.
この子は耳感染症に対する抗体ができるのです
09:53
What you can see is
this huge change in the community,
ここで微生物叢に大きな変化が現れてきて
09:56
followed by a relatively rapid recovery.
耳感染症からの回復が比較的速くなります
09:59
I'll just rewind that for you.
巻き戻してみましょう
10:01
And what we can see is that
just over these few weeks,
ほんのこの数週間で
10:05
we have a much more radical change,
劇的な変化が見られます
10:08
a setback of many months
of normal development,
何ヶ月も進展があまりなく
10:10
followed by a relatively rapid recovery,
838日ぐらいして—
10:13
and by the time he reaches day 838,
このビデオの最後の方ですが—
10:15
which is the end of this video,
比較的回復が早くなるのです
10:19
you can see that he has essentially
reached the healthy adult stool community,
この頃には根本的に
成人の便と同じ微生物叢になります
10:21
despite that antibiotic intervention.
途中 抗生物質の介入
有無に関わらずです
10:25
So this is really interesting
because it raises fundamental questions
実に興味深い事です
なぜなら この事から
10:27
about what happens when we intervene
at different ages in a child's life.
年齢が変わると どうだろうか
という基本的疑問が湧いてくるからです
10:30
So does what we do early on, where
the microbiome is changing so rapidly,
微生物叢の変化が大きい
生後数年間には我々の行動が
10:35
actually matter,
影響するのでしょうか
10:38
or is it like throwing a stone
into a stormy sea,
それともその影響は
あまりに微々たるもので
10:39
where the ripples will just be lost?
何も影響しないのでしょうか
10:42
Well, fascinatingly, it turns out
that if you give children antibiotics
興味深い事に 生後6ヶ月間 嬰児に
10:45
in the first six months of life,
抗生物質を投与すると
10:49
they're more likely
to become obese later on
抗生物質を与えなかった子供と比べ
10:50
than if they don't get antibiotics then
or only get them later,
後に肥満になる率が高い
というデータがあり
10:53
and so what we do early on
may have profound impacts
生後6ヶ月間は十分注意しないと
10:56
on the gut microbial community
and on later health
初期の腸内細菌叢は後々
大きくその人の健康に影響する
10:59
that we're only beginning to understand.
という事が分かってきました
11:03
So this is fascinating, because one day,
in addition to the effects
これで抗生物に対し耐性が出来る
11:05
that antibiotics have
on antibiotic-resistant bacteria,
薬物耐性菌の問題はもちろんの事—
11:09
which are very important,
これは大切な事ですが—
11:12
they may also be degrading
our gut microbial ecosystems,
腸内細菌叢の変化で その保護力が弱まり
11:14
and so one day we may come
to regard antibiotics with the same horror
エジプト人がミイラ作りの際
脳を潰し抽出するのに使った
11:17
that we currently reserve
for those metal tools
金属製の道具に対するような恐怖で
11:20
that the Egyptians used to use
to mush up the brains
我々は抗生物質を扱う事になるかもしれない
11:22
before they drained them out
for embalming.
ということを興味深く考えさせられます
11:25
So I mentioned that microbes
have all these important functions,
これが先ほどの微生物の重要な機能です
11:27
and they've also now,
just over the past few years,
また過去ほんの数年で
11:30
been connected to a whole range
of different diseases,
微生物があらゆる病気
11:32
including inflammatory bowel disease,
炎症性腸疾患、心臓病、結腸がん
11:35
heart disease, colon cancer,
又は肥満にも関連している
11:37
and even obesity.
という事が分かって来たのです
11:39
Obesity has a really
large effect, as it turns out,
肥満には大きく影響し
11:41
and today, we can tell
whether you're lean or obese
今では腸内微生物を見て
11:44
with 90 percent accuracy
90%の正確さで
11:46
by looking at the microbes in your gut.
肥満かどうかわかるのです
11:48
Now, although that might sound impressive,
これに感心なさるかもしれませんが
11:50
in some ways it's a little bit problematic
as a medical test,
ある意味では医療検査としては
ちょっと問題になります
11:52
because you can probably tell
which of these people is obese
恐らく微生物の事など知らなくても
11:56
without knowing anything
about their gut microbes,
見ただけでこの2人のどちらが
肥満がどうか見分けられます
11:59
but it turns out that even
if we sequence their complete genomes
全ゲノムの配列を解読し
12:01
and had all their human DNA,
ヒトDNAから判断すると
12:04
we could only predict which one
was obese with about 60 percent accuracy.
肥満だと決定できるのは
60%の正確さだからです
12:06
So that's amazing, right?
驚きますね
12:10
What it means that the three pounds
of microbes that you carry around with you
ということは我々が抱えている
約1.5キロの微生物は
12:12
may be more important
for some health conditions
ゲノムの遺伝子より
12:16
than every single gene in your genome.
健康には大切なのかもしれません
12:18
And then in mice, we can do a lot more.
それでマウスを使って 色々研究出来
12:23
So in mice, microbes have been linked
to all kinds of additional conditions,
多発性硬化症、鬱病、自閉症
12:25
including things like multiple sclerosis,
肥満などの多くの疾患と
12:29
depression, autism, and again, obesity.
微生物との関係が明らかとなってきました
12:32
But how can we tell whether
these microbial differences
でも どうしてどの微生物が
病気の原因となるのか
12:35
that correlate with disease
are cause or effect?
保護的役割をするのか
知る事が出来るのでしょう?
12:38
Well, one thing we can do
is we can raise some mice
こういう事が出来ます
12:41
without any microbes of their own
in a germ-free bubble.
マウスを微生物のいない
無菌の環境で育て
12:44
Then we can add in some microbes
that we think are important,
その環境に有用微生物と
思われる微生物を加え
12:46
and see what happens.
どうなるか見ます
12:49
When we take the microbes
from an obese mouse
肥満のマウスからの微生物を採り
12:51
and transplant them
into a genetically normal mouse
遺伝的に異常のない
12:54
that's been raised in a bubble
with no microbes of its own,
無菌環境で育てられた
マウスに移植すると
12:56
it becomes fatter than if it got them
from a regular mouse.
同じ微生物を移植された
自然環境のマウスより太ってしまいます
12:59
Why this happens
is absolutely amazing, though.
実に驚くべき出来事です
13:04
Sometimes what's going on
is that the microbes
微生物は食餌の消化を助け
13:06
are helping them digest food
more efficiently from the same diet,
そこから効率よくエネルギーを
13:08
so they're taking more energy
from their food,
取っているという事もありますが
13:11
but other times, the microbes
are actually affecting their behavior.
実際 宿主の行動に影響を与えているのです
13:13
What they're doing is they're eating
more than the normal mouse,
微生物の働きで宿主は普通のマウスより食べ
13:17
so they only get fat if we let them
eat as much as they want.
そんなマウスに好きなだけ
食べさせたら太るだけです
13:20
So this is really remarkable, right?
信じられないようなことですね
13:24
The implication is that microbes
can affect mammalian behavior.
これで微生物はほ乳類の行動に影響する
と言う事が分かります
13:27
So you might be wondering whether we can
also do this sort of thing across species,
では生物種間でもこうなるのだろうか
という疑問が湧いてくると思います
13:33
and it turns out that if you take microbes
from an obese person
肥満の人の微生物を
13:37
and transplant them into mice
you've raised germ-free,
無菌の環境で育ったマウスに移植すると
13:40
those mice will also become fatter
痩せた人の微生物を
13:43
than if they received the microbes
from a lean person,
移植した時より太りましたが
13:45
but we can design a microbial community
that we inoculate them with
肥満を抑制する微生物を培養して
13:48
that prevents them
from gaining this weight.
マウスに移植する事もできます
13:52
We can also do this for malnutrition.
栄養失調に関しても同じ様な研究をしました
13:55
So in a project funded
by the Gates Foundation,
ゲイツ財団の資金を受けたプロジェクトで
13:57
what we're looking at
is children in Malawi
クワシオルコルという栄養失調からくる
14:00
who have kwashiorkor,
a profound form of malnutrition,
深刻な疾患を持つ
マラウイの子供達を見ています
14:02
and mice that get the kwashiorkor
community transplanted into them
クワシオルコルの微生物叢を
移植されたマウスは
14:05
lose 30 percent of their body mass
ほんの3週間で体重が
14:08
in just three weeks,
30%減少します
14:11
but we can restore their health by using
the same peanut butter-based supplement
これは臨床で子供達に使われている
ピーナッツ原料のサプリを使い
14:12
that is used for
the children in the clinic,
健康を回復させる事ができます
14:16
and the mice that receive the community
そして双子のクワシオルコルに
罹っていない方の
14:18
from the healthy identical twins
of the kwashiorkor children do fine.
健康な子どもからの微生物叢を
移植したマウスには問題はありません
14:19
This is truly amazing because it suggests
that we can pilot therapies
これは本当にすごいことです
なぜならヒト腸内細菌叢をマウスで試し
14:24
by trying them out
in a whole bunch of different mice
その結果 自由に操作して
個別化された治療法を
14:27
with individual people's gut communities
生み出せるかもしれないという事を
14:30
and perhaps tailor those therapies
all the way down to the individual level.
示唆しているからです
14:32
So I think it's really important
that everyone has a chance
それで人々がこの発見に参加することは
14:38
to participate in this discovery.
本当に大切だと思い
14:41
So, a couple of years ago,
数年前 こういう事を始めました
14:43
we started this project
called American Gut,
「アメリカの消化器官」
と呼ばれるプロジェクトで
14:45
which allows you to claim a place
for yourself on this microbial map.
微生物分布図のどこに自分がいるのか
見れるようになったのです
14:47
This is now the largest crowd-funded
science project that we know of --
これは最大のクラウドファンディングによる
科学プロジェクトで
14:51
over 8,000 people
have signed up at this point.
この時点で8,000人以上の
人々が登録しています
14:54
What happens is,
they send in their samples,
運営の仕方は まず試料が送られて来
14:57
we sequence the DNA of their microbes
and then release the results back to them.
その人の微生物のDNAが配列され
その本人にそれが送られます
15:00
We also release them, de-identified,
to scientists, to educators,
それは匿名で科学者 教育関係者
15:04
to interested members
of the general public, and so forth,
興味のある一般の人々にも公表し
15:07
so anyone can have access to the data.
誰でもそのデータに
アクセスできるようにします
15:10
On the other hand,
また 同時に
15:13
when we do tours of our lab
at the BioFrontiers Institute,
バイオフロンティア協会の
研究室を見学する人々に
15:15
and we explain that we use robots
and lasers to look at poop,
糞便を見るのにロボットやレーザーを
使う事を説明したりしています
15:18
it turns out that not
everyone wants to know.
別に誰もが知りたい事ではないようですが
15:21
(Laughter)
(笑)
15:25
But I'm guessing that many of you do,
でも皆様はそうでないだろうと思い
15:26
and so I brought some kits here
if you're interested
キットをいくらか持ってきましたので
15:28
in trying this out for yourself.
もし関心がおありなら どうぞお試し下さい
15:30
So why might we want to do this?
こんな事をする理由は
15:35
Well, it turns out that microbes
are not just important
微生物は健康状態を見るのに
15:36
for finding out where we are
in terms of our health,
重要だと言うだけでなく 実際に病気を
15:39
but they can actually cure disease.
治す事が分かったからです
15:42
This is one of the newest things
we've been able to visualize
これはごく最近ミネソタ大学で我々が
15:44
with colleagues
at the University of Minnesota.
考えてきた可能性の1つです
15:47
So here's that map
of the human microbiome again.
もう一度 ヒト微生物の分布図を
15:50
What we're looking at now --
ご覧になると・・・
15:53
I'm going to add in the community
of some people with C. diff.
クロストリジウム・ディフィシルを
持つ人の微生物叢を加えます
15:54
So, this is a terrible form of diarrhea
これは ひどい時は1日に20回も
15:57
where you have to go
up to 20 times a day,
下痢をした人からの微生物です
16:00
and these people have failed
antibiotic therapy for two years
我々の臨床試験に参加できるまで
抗生物質が効かないそんな状態が
16:02
before they're eligible for this trial.
2年間続いていた人々からのものです
16:05
So what would happen if we transplanted
some of the stool from a healthy donor,
では図の下に散らばる健康な人の糞便微生物を
16:08
that star down at the bottom,
この患者達に移植したら どうなるでしょう
16:12
into these patients.
この患者達に移植したら どうなるでしょう
16:14
Would the good microbes
do battle with the bad microbes
善玉菌が悪玉菌と戦ってくれ
16:15
and help to restore their health?
健康が回復するでしょうか
16:18
So let's watch exactly what happens there.
それがどうなるか見てみましょう
16:20
Four of those patients
are about to get a transplant
患者の中の4人が 今 健康な人からの
16:22
from that healthy donor at the bottom,
移植を受け取る寸前です
16:25
and what you can see is that immediately,
そして移植されたかと思うと
16:27
you have this radical change
in the gut community.
瞬く間に腸内細菌叢に劇的変化が現れます
16:29
So one day after you do that transplant,
この移植の翌日
16:31
all those symptoms clear up,
患者はすっかり回復し
16:33
the diarrhea vanishes,
下痢の症状は消えました
16:35
and they're essentially healthy again,
coming to resemble the donor's community,
4人は根本的に健康を取り戻し
微生物叢は健康な提供者のそれに似て
16:36
and they stay there.
今この下に位置しています
16:40
(Applause)
(拍手)
16:42
So we're just at the beginning
of this discovery.
この旅は始まったばかりです
16:49
We're just finding out that microbes
have implications
微生物の炎症性腸疾患から肥満まで
16:51
for all these different kinds of diseases,
あらゆる病気との関係
16:54
ranging from inflammatory
bowel disease to obesity,
また自閉症や鬱病さえとの関連を
16:56
and perhaps even autism and depression.
研究している段階です
16:58
What we need to do, though,
しかし我々は
17:01
is we need to develop
a kind of microbial GPS,
微生物叢の現在地点だけでなく
17:03
where we don't just know
where we are currently
これから行くべき方向に向かうには
何をすべきかを
17:05
but also where we want to go
and what we need to do
知る為に微生物GPSのような物を
17:07
in order to get there,
開発する必要があり
17:11
and we need to be able
to make this simple enough
又これを子供でも使えるような
17:12
that even a child can use it.
(Laughter)
簡単なものにする必要があります
(笑)
17:15
Thank you.
ありがとうございました
17:17
(Applause)
(拍手)
17:20
Translated by Reiko O Bovee
Reviewed by Claire Ghyselen

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About the Speaker:

Rob Knight - Microbial ecologist
Rob Knight explores the unseen microbial world that exists literally right under our noses -- and everywhere else on (and in) our bodies.

Why you should listen
Using scatological research methods that might repel the squeamish, microbial researcher Rob Knight uncovers the secret ecosystem (or "microbiome") of microbes that inhabit our bodies -- and the bodies of every creature on earth. In the process, he’s discovered a complex internal ecology that affects everything from weight loss to our susceptibility to disease. As he said to Nature in 2012, "What motivates me, from a pragmatic standpoint, is how understanding the microbial world might help us improve human and environmental health.”
 
Knight’s recent projects include the American Gut, an attempt to map the unique microbiome of the United States using open-access data mining tools and citizen-scientists to discover how lifestyle and diet affect our internal flora and fauna, and our overall health.
More profile about the speaker
Rob Knight | Speaker | TED.com