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What’s stronger than silk, nylon, or Kevlar?
什么东西比丝绸 尼龙 凯夫拉纤维更强韧？
Well… muscle, apparently.
显然 那就是肌肉
And no, this isn’t a corny message about how nature is the best engineer.
不过别误会 我不是想强调大自然是最好的工程师这种陈词滥调
In a new paper published in the journal Nature Communications,
在一篇新发表在《自然通讯》的论文中
researchers produced super-strong fibers made of muscle proteins.
研究人员用肌肉蛋白制造出了超级强韧的纤维
And the cool part?
最酷的是
They engineered them with the help of protein-assembling microbes,
他们依靠能聚合蛋白质的微生物来制造这些纤维
no animal products required.
不需要任何动物制品
Scientists have known for a long time that muscle is, appropriately, both strong and tough.
科学家很早就已经发现肌肉足够坚韧
That means it can withstand a lot of force before it changes shape,
这说明它可以承受很大的力而不变形
and once it changes shape, it doesn’t easily break.
一旦变形 它也不会轻易断裂
And we’ve been trying to replicate its impressive properties to create new materials.
我们已经在尝试仿造它的优质特性来开发新材料
But the researchers behind this study thought it might be more straightforward
但这项研究背后的学者认为制造肌肉蛋白
to just make muscle proteins.
可能会更直接
The protein they were interested in was titin.
他们感兴趣的蛋白质是肌联蛋白
And titin is one of three key proteins in our cardiac and skeletal muscle.
肌联蛋白是我们心脏和骨骼肌肉中的三大关键蛋白质之一
It’s responsible for much of those muscles’ elasticity and structural integrity.
它很大程度上决定了这些肌肉的弹性和结构完整性
It also happens to be one of the biggest proteins found in nature.
它也恰恰是自然界中最大的蛋白质之一
Like many of nature’s strongest materials,
跟许多天然的强韧材料一样
it’s made up of a massive series of repeating and interlocking units.
它由一大串紧密连接的重复单元组成
That allows it to both withstand passive tension,
这使它既能承受被动张力
and to dissipate energy associated with strain.
也能消除拉力产生的能量
Now, bacteria don’t usually produce proteins anywhere near the size of titin.
细菌一般不会制造像肌联蛋白一样大小的蛋白质
Repetitive proteins like this are prone to mistakes, and cost a lot of energy.
制造像这样重复的蛋白质容易产生错误 且会消耗大量能量
But the researchers were able to engineer titin’s genetic sequence
但研究人员可以改变肌联蛋白的基因序列
so that it was a little more bacteria-friendly.
使其变得对细菌更加友好
The bacteria created short snippets of the repeating amino acid sequence,
细菌会制造一小段重复的氨基酸序列
then strung them together to create a close approximation of the titin protein.
然后将它们串连起来 得到肌联蛋白的类似物
Once the proteins were produced, the researchers spun them into fibers.
蛋白质被制造出来后 研究人员将它们编织成纤维
Only one-tenth the width of a human hair,
宽度只有人类头发的1/10
the fibers were both stronger and tougher than actual muscle fibers.
这种纤维比实际的肌肉纤维更坚韧
They were also tougher than most natural and synthetic fibers.
它们也比大多数天然及合成纤维更强韧
And these fibers actually got better at dealing with strain
实际上这些纤维的在抗拉力方面强度更高
as the amount of strain on them increased, and as the fibers elongated.
当拉力增加时 这些纤维会被拉长
This was expected, since it’s similar to how natural titin works,
这是符合预期的 因为它和天然的肌联蛋白相似
but the synthetic fibers actually did it better than natural titin.
但合成纤维实际上比天然肌联蛋白效果更好
These fibers could be strong enough to be used for protective clothing
这些纤维足够强韧 可以用作防护型衣物
like bulletproof vests.
比如防弹背心
But their most interesting potential uses are the biomedical ones.
但它们最有趣的潜在用途是生物医学方面
Since they’re literally made of muscle,
因为它们就是由肌肉组成的
they could potentially be used for surgical stitches or for tissue engineering.
所以它们可以用于手术缝线或组织工程
The researchers say these fibers could be a sustainable alternative
研究人员指出这些纤维可以作为传统石油产品的
to conventional petroleum-produced ones.
可持续替代品
And this research may open the door
这项研究可以为
for using microbes to produce all kinds of large-scale materials.
使用微生物制造各种大型材料提供可能
And now, it’s time to talk about something tastier.
现在该谈一谈好吃的了
Or at least we assume that this is tastier than the muscle fiber clothing…
我们看来它至少比肌肉纤维衣物更好吃
We’re going to talk about chocolate.
我们要谈一谈巧克力
And to be at its best, chocolate needs to be tempered.
为了达到最好的口感 巧克力需要调温
That’s the tricky process by which chocolate is heated, and then cooled,
这个过程很复杂 巧克力需要先加热然后冷却
and then heated again before solidifying to form a smooth, shiny product
然后在固化前再加热 形成丝滑 有光泽的产品
that snaps cleanly and melts in your mouth.
咔嚓断裂 并融化在口中
Tempering is the bane of amateur bakers everywhere.
调温是每位业余烘焙师头疼的过程
And while we probably can’t get microbes to do it for us,
虽然我们无法让微生物帮我们
it turns out that small molecules found in our own cells might be able to help.
但我们发现我们自身细胞中的一些小分子可能会派上用场
More new research from Nature Communications
更多《自然通讯》的新研究
presents a method of adding small fat molecules to chocolate
提出了一种方法 在巧克力中加入小脂肪分子
that might someday render tempering totally unnecessary.
有朝一日或许可以使调温变得完全没必要
The fats in foods are mostly composed of molecules called triacylglycerols,
食物中的脂肪主要由一种叫甘油三酯的分子组成
which crystallize when they solidify to form complex structures.
它们在固化时会结晶形成复杂的结构
Cocoa butter, the fat found in chocolate, is particularly complicated.
可可脂是巧克力中的一种脂肪 特别复杂
It actually has six different crystalline structures it can take on
当它融化然后再固化时
when it melts and then solidifies.
可以形成6种不同的晶体结构
All of them have different melting points,
这6种结构都有不同的熔点
and all of them affect the final texture of the chocolate.
而且它们也会影响巧克力最终的口感
That’s why tempering is so temperamental.
所以调温非常容易让人恼火
You’re looking for just one of those crystal structures, called Form V.
你只需要其中的一种晶体结构 叫做形态5
In tempering, the chocolate reaches a temperature high enough to melt all the crystals.
调温时 巧克力需要达到足够高的温度来使所有晶体熔化
Then it’s cooled slowly at room temperature, which allows Form V crystals to form,
然后缓慢冷却到室温 可以形成形态5的晶体
alongside a few pesky Form IV crystals.
同时还会形成少量不必要的形态4晶体
These early crystals are what’s known as seed crystals,
这些成型较早的晶体叫做晶核
and they act as templates to encourage
随着可可脂继续固化
the formation of more crystals just like them as the cocoa butter continues to solidify.
晶核可促进与其形态类似的更多晶体形成
To keep the Form IV crystals from egging on additional Form IV crystals,
为了防止形态4晶体继续产生过多的晶体
the chocolate is heated just a bit again.
巧克力需要再略微加热
And because Form IV has a lower melting point than Form V,
由于形态4比形态5熔点低
the unwanted crystals melt again.
不需要的晶体再次熔化
And the resulting chocolate is Form V perfect:
最后得到的巧克力是完美的形态5晶体
shiny and melt-in-your-mouth, with a long shelf life.
有光泽 入口即化 有更长的保质期
I bet you didn’t realize all of this was so complicated!
我猜你肯定不知道这有这么复杂
But there are more than just triacylglycerols in food fats.
但食物中的脂肪不仅仅只有甘油三酯
There’s also a whole smorgasbord of smaller molecules, called minor components.
还有各式各样的小分子 称作微量组分
Previous studies had hypothesized that
之前已有研究猜测
minor components could either help or hinder the crystallization process,
微量组分可以产生或堵塞晶体生长的位点
by creating or blocking sites for crystal growth.
从而促进或阻碍结晶过程
But the researchers in this study wanted to see
但从事这项研究的人员想知道
if adding particular minor components in the right amounts
加入某种适量的微量组分
could promote Form V crystal production.
能否提高形态5晶体的产量
They were particularly interested in molecules called phospholipids.
他们对一种叫磷脂的分子非常感兴趣
These molecules are actually found in cell membranes,
这种分子存在于细胞膜中
and are great at assembling into structures that
它们可以轻松形成一道屏障
keep our cells’ outsides separate from their insides.
将我们细胞的外部和内部隔开
And the researchers thought the molecular properties that let them do that
研究人员认为分子的这种特性
might also let them aid chocolate crystal formation.
也可能有助于巧克力晶体的形成
They found that cocoa butter containing certain phospholipids crystallized more quickly
他们发现含特定磷脂的可可脂结晶更快
and tended towards everyone’s favorite Form V.
并易于形成人们最爱的形态5晶体
And when the phospholipids were added to commercial chocolate,
当磷脂加入到巧克力商品中时
they produced chocolate with ideal shine, snap, and melt,
所产生的巧克力具有理想的光泽 酥脆 入口即化
all without the fussy tempering that would usually have been necessary.
使繁琐的调温变得不再必要
The researchers say that their study highlights just how complicated
研究人员指出他们的研究凸显了
the quest for perfect chocolate can be.
得到一份完美的巧克力有多复杂
But they do think that, with some more tweaking,
但他们认为 经过一些调整
their new method could pave the way for self-tempering chocolate!
他们的新方法可以为自调温巧克力铺平道路
And who isn’t a fan of easier, better chocolate?
谁不喜欢制作简单 味道更好的巧克力呢
Thanks for watching this episode of SciShow,
感谢观看本期《科学秀》
and thanks to this month’s President of Science, Emily Z.!
感谢本月的科学会长 Emily Z.
Happy birthday, Emily, and thank you for your support.
生日快乐 Emily 感谢支持
If you want to become President of Science yourself,
如果你自己想成为科学会长
or maybe hook somebody up with a fun birthday surprise,
或是想给别人来一个有趣的生日惊喜
you can get started at patreon.com/scishow.
你可以登陆patreon.com/scishow
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