How you can make a fruit fly eat veggies | DIY Neuroscience, a TED series

Translator: Joseph Geni Reviewer: Krystian Aparta

譯者: Joey Chung 審譯者: Helen Chang

Greg Gage: It's an age-old pursuit of all parents,

葛列格·蓋奇（GG）: 一直以來， 所有父母都追求，

getting their kids to eat their vegetables.

想盡辦法讓孩子吃蔬菜，

But getting them to eat cookies or ice cream

但是讓他們吃餅乾或雪糕

is relatively easy,

可能相對容易得多，

and that's because our brains prefer sweetness.

這是因為我們的大腦偏愛甜食。

Now, there's a new technology called optogenetics

現在有一項新的技術叫光遺傳學，

which may be able to trick our taste buds,

或許可以迷惑味蕾，

for instance preferring vegetables over sweets.

比如，讓我們更喜歡蔬菜而不是甜食。

We're going to try this today using fruit flies.

今天我們要用果蠅來做實驗。

[DIY Neuroscience]

【DIY 神經科學】

The reason why we experiment with fruit flies

我們選擇果蠅來做實驗的原因是

is they have a small enough nervous system

牠們的神經系統夠小，

that gives us a fighting chance to really understand what's going on.

讓我們有一觸即發的機會 去理解其中的機制。

And believe it or not, their taste buds are very similar to ours.

而且，信不信由你， 牠們的味蕾和我們的十分相似。

But before we try to manipulate their taste preferences,

不過，在操縱牠們的味蕾之前，

we need to establish: What is the baseline of the fruit fly?

我們得要先弄明白 果蠅原本的情況是什麼樣的？

What does it prefer?

即是牠們原來喜歡什麼？

We call this a control experiment.

我們稱這個為控制試驗。

Spencer's been hard at work doing this.

就像斯賓塞正在做的那樣。

OK, Spencer, let's do our first experiment.

好吧，斯賓塞，讓我們 來做第一個實驗。

We want to test to see if fruit flies prefer bananas or broccoli.

我們想測試果蠅 更喜歡香蕉還是青花菜。

So what do we need?

所以我們需要準備些什麼呢？

Spencer Brown: So we need the fly pad, which is basically an iPad for flies.

斯賓塞·布朗（SB）：我們需要

一個果蠅平板， 相當於果蠅的平板電腦，

它能夠感應碰觸。

It measures the touch.

GG: You put a fly in each chamber?

GG：在每個格子裡放一隻果蠅嗎？

SB: Yeah. Inside, we'll offer them banana and broccoli

SB：對，在每個格子裡 給牠們提供香蕉和青花菜，

to see which one they prefer.

看看牠們更喜歡哪一個。

GG: In order to count how many times

GG：為了統計果蠅

the fruit fly eats a banana versus the broccoli,

吃香蕉和青花菜的次數，

these chambers have been outfitted with a small electrode

每個格子都裝備了一個小電極，

that sends data to a computer.

能把信號傳回電腦。

And so what were your findings on banana versus broccoli?

所以，你從這個實驗中發現 香蕉及青花菜分別怎樣？

SB: I found that the flies visited banana the most.

SB：我發現這些果蠅更常吃香蕉。

GG: Both were there, but like most kids,

GG：兩種食物都在那裡， 但是像很多孩子一樣，

they choose not to eat the broccoli, and they go switch to something sweeter.

牠們選擇不吃青花菜， 而是轉向更甜的東西。

SB：沒錯。

GG: Now a quick background on how taste works.

GG：簡單講一下味覺的原理。

Taste buds are made up of specialized neurons

味蕾是由特殊的神經元組成的，

called taste receptors.

稱為味覺感受器。

When we eat something that triggers a particular taste,

我們吃東西的時候 會產生一種味覺，

those taste neurons will fire a signal to the brain.

味覺感受器就會向大腦發送信號，

This allows our brain to know what's sweet and what's bitter.

這樣大腦就可以知道 什麼是甜的，什麼是苦的 。

So when a fruit fly eats a banana, its sweet taste neurons will fire.

當果蠅吃香蕉時， 牠的甜味感受器就會發送信號。

But when it eats broccoli, those same neurons stay pretty quiet.

吃青花菜的時候， 同樣的感受器並不活躍。

But what if we could force those sweet-tasting neurons to fire

但是如果我們能強制讓甜味感受器

every time the fruit fly eats broccoli?

在吃青花菜的時候發送信號？

We may be able to get the fruit fly

我們就有可能讓果蠅

像喜歡香蕉一樣喜歡青花菜。

to like broccoli as much as banana.

Enter optogenetics.

光遺傳學。

This is the revolutionary new tool that's taking neuroscience by storm,

這個革命性的新技術 引發神經科學領域的廣泛討論，

and in this case, "opto" means light

這裡「opto」是光的意思，

and "genetic" refers to the fact that these fruit flies have been modified

而「genetic」表示 果蠅被改造後有種特殊的基因

to contain a special gene that makes only certain neurons respond to light.

只讓某些特定的神經元 對光線作出反應。

In our case, we've added the special gene to the sweet taste receptors.

我們在這實驗的甜味感受器中 加入這種特殊基因。

Now here's the fun part.

接下來就非常有趣了。

Optogenetics means that we can control these special neurons

光遺傳意味著我們可以讓神經元

whenever they're exposed to a bright-colored light,

在受到明亮顏色的光照射時

causing them to send messages to the brain.

向大腦發出信號。

In this experiment, we're going to have these modified fruit flies

在這個實驗中，我們要 讓這些改造過的果蠅

choose between banana and broccoli again,

再次在香蕉和青花菜中做出選擇。

only this time, every time the fruit fly eats the broccoli,

但是這一次，每當果蠅吃青花菜時，

we're going to trigger a big bright red light.

我們會打開一個高亮度的紅燈。

And when the channels see that red light, they're going to open up,

當甜味感受器感受到這種光照射， 味蕾的神經系統會開動，

and they're going to cause that neuron to fire,

同時神經元會進入興奮狀態，

and the sweet taste message will be sent to the brain.

把甜味資訊傳到大腦。

你怎麼讓果蠅出來呢？

How do you get them out?

SB: So we're going to be using a mouth aspirator,

SB：我們要用一個口抽吸器

so it's just two straws put together.

就是兩根吸管拼一起。

GG: So it's a fancy name for a straw.

GG：說白了還是吸管。

SB: Basically.

SB：差不多吧。

GG: So you're going to suck those out.

GG：所以你要把牠們吸出來。

Have you ever sucked up a fly before?

你曾經把果蠅吸到嘴裡嗎？

SB: Once or twice.

SB：一兩次吧。

GG: There we go. You got all four.

GG：好了，四個都出來了，

OK, perfect.

好，完美。

So you're going to turn on your OptoStimmers here.

所以你要在這裡打開 你的光電刺激器。

You're going to park the light right on top of the chambers.

你要把光源放在這些格子的正上方，

So now we sit here and we wait for them to eat broccoli,

然後我們坐這裡等牠們吃青花菜，

and then when the light fires,

燈一亮起來，

they're going to think it's tasting something sweet.

牠們就會認為青花菜是甜的。

Come on. Oh, he's getting closer.

快點啊，看一下，牠要過去了。

Come on. It tastes good now.

快點，現在變好吃了。

SB: It's about to.

SB：快了。

GG: Oh, he's back. All right!

GG：哦，牠進去了。太好了！

All right, so now we see that some of these flies

好了，我們現在看到其中一些果蠅

are switching over from the banana to the broccoli.

從吃香蕉變成了吃青花菜。

SB: Exactly, yeah.

SB : 沒錯。

GG: Every time this light goes off,

GG：每當這個燈亮起來，

that means that they think they're tasting something sweet.

即是牠們會認為自己在吃甜的東西。

SB：對，牠們真的在燈亮後去吃。

SB: Yeah. So this guy's really going after it.

GG：所以我們看到， 我們可以拯救青花菜

GG: So we saw that we were able to rescue broccoli

and make it just as appealing as banana to our fruit flies.

並令青花菜變成與香蕉一樣， 對果繩而言，有同樣的吸引力。

我們每個實驗都得到同樣的結果。

And we're able to replicate these same results

in all of our experiments.

所以，現在的問題是： 這適用於人類嗎？

So the question is: Can we do the same thing in humans?

Well, that depends on a number of items.

好吧，這取決於很多要素。

First, do optogenetic tools even work in humans?

首先，光遺傳的技術 對人類有作用嗎？

And that looks like the answer is yes,

可以說這個答案看起來是肯定的，

and in fact, clinical trials are already being planned

而且事實上，在臨床試驗中 已有實際的計劃

that will treat chronic pain and blindness using optogenetics.

把光遺傳治療應用於 慢性痛症和失明。

And the next question is, can we easily trigger a light source

而下一個問題是， 我們能不能很容易地接觸光源

so that every time we eat vegetables, it will go off?

可以在每次吃蔬菜的時候 都把燈亮起來？

For that, I'm afraid at least at this time, the answer is still no.

目前來看不怎麼可行。

But today, we got to witness just a taste of optogenetics

但是最少今天我們見證到光遺傳學

and its amazing potential.

及其著格外光明的前景了。

(Music)

（音樂）