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

Translator: Joseph Geni Reviewer: Krystian Aparta

翻译人员: Cecilia Zhang 校对人员: Jiasi Hao

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

格雷格 · 盖奇（Greg Gage）： 长久以来，所有家长使尽浑身解数，

getting their kids to eat their vegetables.

就为了让孩子吃蔬菜，

But getting them to eat cookies or ice cream

但是让他们吃饼干和冰淇凌

is relatively easy,

却容易得多。

and that's because our brains prefer sweetness.

这是因为我们的大脑偏爱甜食。

Now, there's a new technology called optogenetics

一项新的技术，“光遗传学”，

which may be able to trick our taste buds,

或许可以迷惑我们的味蕾，

for instance preferring vegetables over sweets.

比如，让我们更喜欢蔬菜而非甜食。

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

今天我们要用果蝇来做实验。

[DIY Neuroscience]

[ DIY 神经科学 ]

The reason why we experiment with fruit flies

我们选果蝇来做实验的原因是

is they have a small enough nervous system

它们的神经系统很小，

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

从而能让我们有一丝机会 去理解其中的神经运作机制。

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

并且随便你信不信， 它们的味蕾和我们的十分相似。

But before we try to manipulate their taste preferences,

不过，在操纵它们的口味偏好前，

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

我们要先明白： 果蝇基准偏好是什么？

What does it prefer?

它们原本喜欢什么味道？

We call this a control experiment.

我们称之为一组对照试验——

Spencer's been hard at work doing this.

就像斯宾塞正努力做的实验。

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

斯宾塞，让我们来做第一个实验。

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

我们想测试果蝇 更喜欢香蕉还是西兰花，

So what do we need?

那我们需要准备些什么呢？

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

斯宾塞 · 布朗（Spencer Brown）： 我们需要一个果蝇平板，类似果蝇的 iPad，

It measures the touch.

它能够感应并测量触摸。

GG: You put a fly in each chamber?

GG：你在每个格子里放一只果蝇吗？

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

SB：对。在每个格子里我们 也会给它们提供香蕉和西兰花，

to see which one they prefer.

看看它们更喜欢哪个。

GG: In order to count how many times

GG：为了统计果蝇

the fruit fly eats a banana versus the broccoli,

吃香蕉和西兰花的次数，

these chambers have been outfitted with a small electrode

每个格子都装备了一个小电极，

that sends data to a computer.

能把信号数据传回电脑。

And so what were your findings on banana versus broccoli?

所以，在这个实验中 你的发现是什么？

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

SB：我发现这些果蝇 吃香蕉的次数更多。

GG: Both were there, but like most kids,

GG：两种食物都在那里， 但是像很多孩子一样，

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

它们也选择不吃西兰花， 而是转向更甜的食物。

GG: Now a quick background on how taste works.

GG：让我们简单介绍一下 味觉的原理。

Taste buds are made up of specialized neurons

味蕾是由一种叫“味觉感受器”的

called taste receptors.

特殊神经元组成的。

When we eat something that triggers a particular taste,

我们吃东西的时候 会触发一种特定的味觉，

those taste neurons will fire a signal to the brain.

这些相应的味觉感受器随之 会向大脑发送信号，

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

于是大脑便可以知道 什么是甜的，什么是苦的。

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

所以当果蝇吃香蕉时， 它的甜味感受器就会发送信号。

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

而吃西兰花的时候， 这些神经元就会保持相对稳定。

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

但是如果我们可以 在果蝇吃西兰花的时候

every time the fruit fly eats broccoli?

强制刺激甜味感受器发送信号， 那会怎么样？

We may be able to get the fruit fly

我们有可能让果蝇

to like broccoli as much as banana.

像喜欢香蕉一样喜欢西兰花。

Enter optogenetics.

“光遗传学”（Optogenetics），

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

这个革命性的新技术 正在席卷神经科学领域。

and in this case, "opto" means light

这里，“opto” 是光的意思，

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

“genetic” 则表示果蝇 被一种特殊的基因修改。

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

这种基因只让某些特定的神经元 对光线作出反应。

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

因此我们的实验中，我们 在甜味感受器中嵌入了这种特殊基因。

Now here's the fun part.

接下来就非常有趣了。

Optogenetics means that we can control these special neurons

光遗传意味着 我们可以让神经元

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

在受到明亮颜色的光线照射时

causing them to send messages to the brain.

向大脑发出信号。

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

在这个实验中，我们要 让这些被修改的果蝇

choose between banana and broccoli again,

再次在香蕉和西兰花中 做出选择。

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

但是这一次， 每当果蝇吃西兰花时，

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

我们会设计 触发一个高亮度的红灯。

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

甜味感受器上的通道 受到这种光照射时就会打开，

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

使神经元进入兴奋状态，

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

甜味信息传送至大脑。

How do you get them out?

你怎么把果蝇弄出来呢？

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

SB：我们要用一个口抽吸器——

so it's just two straws put together.

就只是把两根吸管拼一起。

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

GG：说白了还是吸管。

SB: Basically.

SB：差不多吧。

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

GG：所以你要把它们吸出来。

Have you ever sucked up a fly before?

你以前吸过果蝇吗？

SB: Once or twice.

SB：一两次吧。

GG: There we go. You got all four.

GG：好了，四个都出来了，

OK, perfect.

完美。

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

现在你在电脑上 打开 OptoStimmer 软件，

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

再把光源放在这些格子的正上方，

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

然后我们坐在这里 等它们吃西兰花。

and then when the light fires,

现在每当灯一亮起来，

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

它们就会认为自己在吃甜的东西。

Come on. Oh, he's getting closer.

快啊，哦！它要过去了，

Come on. It tastes good now.

快点，现在西兰花变好吃了。

SB: It's about to.

SB：快了。

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

GG：哦，它进去了。太好了！

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

现在我们看到，其中一些果蝇

are switching over from the banana to the broccoli.

从吃香蕉 变成了吃西兰花。

SB: Exactly, yeah.

SB：对，没错。

GG: Every time this light goes off,

GG：每当这个灯亮起来，

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

它们会认为自己在吃甜的东西。

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

SB：对，它们真的很喜欢甜食。

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

GG：我们看到，对于果蝇， 我们可以让西兰花

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

变得和香蕉一样诱人。

And we're able to replicate these same results

我们所有的实验，

in all of our experiments.

我们都能够复制这一实验结果。

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

现在的问题是：这适用于人类吗？

Well, that depends on a number of items.

这取决于很多条件。

First, do optogenetic tools even work in humans?

首先，光遗传工具对人类 真的有用吗？

And that looks like the answer is yes,

这个答案看起来是肯定的，

and in fact, clinical trials are already being planned

实际上，已经研究人员 计划在临床试验中

that will treat chronic pain and blindness using optogenetics.

使用光遗传治疗慢性痛症和失明。

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

下一个问题是， 我们能不能在某人吃蔬菜的时候

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

触发一处光源？

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

目前来看，这可能无法做到。

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

但如今，我们已经能够 浅尝光遗传学应用带来的好处，

and its amazing potential.

并预见其格外光明的前景。

(Music)

（音乐）