Greg Gage: It's an age-old pursuit of all parents, getting their kids to eat their vegetables. But getting them to eat cookies or ice cream is relatively easy, and that's because our brains prefer sweetness. Now, there's a new technology called optogenetics which may be able to trick our taste buds, for instance preferring vegetables over sweets. We're going to try this today using fruit flies.
Sejak dulu, para orang tua kesulitan membuat anak-anaknya makan sayuran. Padahal, meminta mereka untuk makan biskuit atau es krim relatif mudah. Itu karena otak kita lebih suka manis. Kini, ada teknologi baru yang disebut optogenetika, yang mungkin bisa menipu kuncup perasa, misalnya menjadi lebih suka sayur daripada permen. Kita akan mencobanya pada lalat buah.
[DIY Neuroscience]
The reason why we experiment with fruit flies is they have a small enough nervous system that gives us a fighting chance to really understand what's going on. And believe it or not, their taste buds are very similar to ours. But before we try to manipulate their taste preferences, we need to establish: What is the baseline of the fruit fly? What does it prefer? We call this a control experiment. Spencer's been hard at work doing this.
Alasan kita mencobanya pada lalat buah adalah karena sistem sarafnya yang kecil sehingga akan lebih memudahkan kita untuk memahami prosesnya. Percaya atau tidak, kuncup perasa lalat sangat mirip dengan kita. Sebelum memanipulasi kesukaan lalat terhadap rasa, kita harus menetapkan garis acuan pada lalat buah. Apa yang disukainya? Kita menyebutnya percobaan kontrol. Spencer telah bekerja keras melakukannya. Gage: Spencer, ayo lakukan percobaan awal.
OK, Spencer, let's do our first experiment. We want to test to see if fruit flies prefer bananas or broccoli. So what do we need?
Kita ingin tahu apakah lalat buah lebih suka pisang atau brokoli. Apa yang kita butuhkan? Spencer: Kita butuh <i>fly pad</i>, yaitu iPad untuk lalat.
Spencer Brown: So we need the fly pad, which is basically an iPad for flies. It measures the touch.
Alat ini mengukur sentuhan. Satu lalat di dalam tiap bilik?
GG: You put a fly in each chamber?
SB: Yeah. Inside, we'll offer them banana and broccoli to see which one they prefer.
Ya. Di situ, kita beri mereka pisang dan brokoli agar tahu mana yang disukai. Untuk menghitung berapa kali lalat buah memakan pisang atau brokoli,
GG: In order to count how many times the fruit fly eats a banana versus the broccoli, these chambers have been outfitted with a small electrode that sends data to a computer. And so what were your findings on banana versus broccoli?
bilik ini telah dipasangi elektroda kecil yang mengirimkan data ke komputer. Jadi, apa hasilnya, antara pisang dan brokoli? Kebanyakan lalat buah itu menghampiri pisang.
SB: I found that the flies visited banana the most.
Jadi, meski ada dua opsi, seperti anak-anak,
GG: Both were there, but like most kids, they choose not to eat the broccoli, and they go switch to something sweeter.
mereka menolak makan brokoli dan memilih yang lebih manis. Tepat.
GG: Now a quick background on how taste works. Taste buds are made up of specialized neurons called taste receptors. When we eat something that triggers a particular taste, those taste neurons will fire a signal to the brain. This allows our brain to know what's sweet and what's bitter. So when a fruit fly eats a banana, its sweet taste neurons will fire. But when it eats broccoli, those same neurons stay pretty quiet. But what if we could force those sweet-tasting neurons to fire every time the fruit fly eats broccoli? We may be able to get the fruit fly to like broccoli as much as banana.
Sekarang, kita tinjau cara kerja pengecap. Kuncup perasa terdiri dari sel saraf khusus, yaitu reseptor pengecap. Saat kita memakan sesuatu yang memicu rasa tertentu, saraf pengecap itu akan mengirimkan sinyal ke otak. Inilah cara otak kita membedakan rasa manis dan pahit. Maka, saat lalat buah makan pisang, saraf pengecap manis mengirimkan sinyal. Tetapi, saat lalat makan brokoli, saraf tersebut akan diam saja. Bagaimana jika kita bisa memaksa saraf itu mengirim sinyal tiap lalat makan brokoli? Kita mungkin bisa membuat lalat buah menyukai brokoli sama seperti pisang. Di sinilah peran optogenetika.
Enter optogenetics. This is the revolutionary new tool that's taking neuroscience by storm, and in this case, "opto" means light and "genetic" refers to the fact that these fruit flies have been modified to contain a special gene that makes only certain neurons respond to light. In our case, we've added the special gene to the sweet taste receptors.
Teknik baru yang revolusioner ini menghebohkan dunia ilmu saraf, Dalam hal ini, ”opto” berarti cahaya, sedangkan “genetika” mengacu pada modifikasi terhadap lalat buah untuk menyimpan gen khusus yang membuat hanya sel saraf tertentu bisa merespons cahaya. Di sini, kami menambahkan gen khusus itu ke reseptor pengecap manis.
Now here's the fun part. Optogenetics means that we can control these special neurons whenever they're exposed to a bright-colored light, causing them to send messages to the brain. In this experiment, we're going to have these modified fruit flies choose between banana and broccoli again, only this time, every time the fruit fly eats the broccoli, we're going to trigger a big bright red light. And when the channels see that red light, they're going to open up, and they're going to cause that neuron to fire, and the sweet taste message will be sent to the brain.
Di sinilah menariknya. Optogenetika memungkinkan kita mengendalikan sel saraf khusus ini setiap kali mereka terpapar oleh cahaya berwarna cerah, sehingga mereka mengirimkan pesan ke otak. Dalam percobaan ini, kami akan membuat lalat termodifikasi ini untuk memilih pisang atau brokoli lagi, hanya saja kali ini, setiap kali lalat buah memakan brokoli, kami akan menyalakan cahaya merah terang. Saat kanal mendeteksi cahaya merah itu, kanal akan terbuka dan sel saraf akan mengirimkan sinyal dan pesan rasa manis akan dikirim ke otak.
How do you get them out?
Bagaimana mengeluarkan lalat itu?
SB: So we're going to be using a mouth aspirator, so it's just two straws put together.
Kita akan menggunakan aspirator mulut, terbuat dari gabungan dua sedotan. Jadi, nama keren sedotan.
GG: So it's a fancy name for a straw.
Baiklah.
SB: Basically.
Begitulah.
GG: So you're going to suck those out. Have you ever sucked up a fly before?
- Jadi kamu akan menyedotnya keluar. - Ya. Apakah lalatnya pernah tertelan?
SB: Once or twice.
Sekali atau dua kali.
GG: There we go. You got all four. OK, perfect. So you're going to turn on your OptoStimmers here. You're going to park the light right on top of the chambers. So now we sit here and we wait for them to eat broccoli, and then when the light fires, they're going to think it's tasting something sweet.
Baik, sudah keempat-empatnya. Sempurna. Selanjutnya, nyalakan OptoStimmers, lalu kamu letakkan lampunya tepat di atas bilik. Kita tinggal duduk dan menunggu mereka makan brokoli, lalu saat lampunya menyala, mereka akan mengira itu rasanya manis. Ayo. Oh, ia makin dekat.
Come on. Oh, he's getting closer. Come on. It tastes good now.
Ayolah. Sekarang rasanya enak. Sebentar lagi.
SB: It's about to.
GG: Oh, he's back. All right! All right, so now we see that some of these flies are switching over from the banana to the broccoli.
Oh, dia kembali. Bagus! Baik, sekarang kita lihat sebagian lalat ini beralih dari pisang ke brokoli.
SB: Exactly, yeah.
Tepat sekali.
GG: Every time this light goes off, that means that they think they're tasting something sweet.
Setiap kali lampu ini menyala, mereka mengira sedang merasakan sesuatu yang manis.
SB: Yeah. So this guy's really going after it.
Ya. Jadi, lalat ini akan terus mencarinya.
GG: So we saw that we were able to rescue broccoli and make it just as appealing as banana to our fruit flies. And we're able to replicate these same results in all of our experiments. So the question is: Can we do the same thing in humans? Well, that depends on a number of items. First, do optogenetic tools even work in humans? And that looks like the answer is yes, and in fact, clinical trials are already being planned that will treat chronic pain and blindness using optogenetics. And the next question is, can we easily trigger a light source so that every time we eat vegetables, it will go off? For that, I'm afraid at least at this time, the answer is still no. But today, we got to witness just a taste of optogenetics and its amazing potential.
Jadi, kita berhasil membuat brokoli terasa sama enaknya dengan pisang bagi lalat buah kami. Hasil yang sama juga didapatkan setiap saat percobaan kami diulang. Kini pertanyaannya: Dapatkah kita melakukannya pada manusia? Nah, itu tergantung pada beberapa hal. Pertama, apakah optogenetika benar-benar bisa diterapkan pada manusia? Ternyata, kelihatannya bisa. Bahkan, uji klinis telah direncanakan untuk menangani sakit kronis dan kebutaan menggunakan optogenetika. Pertanyaan berikutnya, bisakah kita mengatur agar sumber cahaya menyala setiap kali makan sayuran? Untuk hal ini, setidaknya untuk sekarang, sayangnya masih belum bisa. Tetapi, kita baru saja menyaksikan kekuatan kecil dari optogenetika dan potensinya yang menakjubkan.
(Music)