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生命起源的新数学模型 – 译学馆
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生命起源的新数学模型

A New Mathematical Model of the Origin of Life

[开场曲]
[INTRO ♪]
数学建模看起来是种枯燥无味的专业
Mathematical modeling can seem like maybe a dry profession,
但当你想从多种不同的领域获取结果时
but when you get to pull in findings from a half dozen different fields,
(数学建模的)结果可能会让人惊喜
the results can be especially awesome.
比如 由加拿大和德国的科学家组成的小组
Like, a paper published this week by a team of scientists in Canada and Germany
在本周发表一篇论文 肯定了达尔文的一个推测
confirming a piece of speculation going all the way back to Darwin.
这项研究显示 地球上的生命
This research suggests that the Earth’s biochemistry
可能起源于一个温暖的小池塘
could’ve originated in warm ponds
它们分布在37至45亿年前新形成的大陆上
on newly formed continents between 4.5 and 3.7 billion years ago,
过去频繁撞击地球的陨石也有帮助
with the help of meteor strikes that used to rock the planet.
它支持这种推测 即最早的生化进程
And it supports the hypothesis that the earliest biochemical processes
是以核糖核酸或RNA为中心
centered around ribonucleic acid, or RNA.
科学小组为这篇论文构建了一个详细的
For this paper, the team constructed a detailed mathematical model
关于早期地球情况的模型
of the conditions of early Earth,
模型中布满小池塘
and filled that model with small ponds.
它们足够小 以至于会随季节循环而干涸
The ponds were small enough that they would sometimes dry out in seasonal cycles.
该模型说明 陨石给(合成RNA的)化学反应
Their model accounted for meteorites supplying some raw materials
提供了一些原材料 如核酸碱基
for chemical reactions, like nucleobases,
核酸碱基是构成DNA或RNA的建筑模块
which are some of the building blocks of DNA and RNA.
先前的研究发现 核酸碱基能够在太空中形成
Previous research has found that nucleobases can actually be formed in space,
以前我们也在陨石中发现过它们
and we’ve found them in meteorites before.
要是没有这些核酸碱 智能生命不会出现
But for those nucleobases to do anything life-wise.
它们必须聚在一起形成一条化学长链或聚合物
They have to come together in a chemical chain, or polymer.
这个小组的模型发现 如果池塘周期性的干涸
The team’s model found that if the ponds were able to dry out periodically,
(水份)蒸发和(化学物质)沉淀的循环
the evaporation and precipitation cycles
为RNA聚合物的形成及保持相对稳定
created the right conditions for RNA polymers
创造了合适的条件
to form and remain fairly stable.
其他实验室研究发现 (池塘的)干热阶段
Other lab studies have suggested that a hot and dry step could
能浓缩(组成RNA的)材料
concentrate the ingredients
促进组成聚合物化学键的反应
and encourage the reactions that form the polymer bonds.
然后水分增加让所有材料很好的混合起来
And then adding water gives everything a good mix
形成更多化学成分
to bring in more chemical components.
比如在我们体内的细胞里
In cells like ours,
RNA是合成DNA和蛋白质的中间载体
RNA acts as a go-between for DNA and protein.
此外 它还组成一些最古老的细胞结构 如核糖体
Plus it makes up some of the most ancient cellular structures, like ribosomes.
所以有些研究人员假设RNA过去常常承担
So some researchers hypothesize that RNA used to fulfill the roles
遗传密码以及(组成)生物结构的作用
of genetic code and biological machinery—
直到更稳定灵活的DNA和蛋白质取代那些工作
until more stable, more flexible DNA and protein took on those jobs.
这个小组将先前化学和天体物理学等
This team pieced together prior research from fields
领域的研究整合在一起
as diverse as chemistry and astrophysics
首次做出关于早期地球情况的模拟计算
to do a calculation no one’s ever done before about the state of the early Earth,
尽管这些概念已经面世了一段时间
although these ideas have been floating around for a while.
“温暖的小池塘”这句话实际上出自查理·达尔文
The phrase “warm little pond” was actually coined by Charles Darwin,
他构想了一个地方
who imagined a place with
那里充满了营养素以及生命起源所需的能量
plenty of nutrients and energy for the chemical origins of life,
不过达尔文不是生物化学家
and while Darwin was no biochemist,
所以这个构想没有后文
the idea has held up.
最近十年来 一些科学家认为深海热泉
In recent decades, some have argued that deep sea hydrothermal vents
比地面上的小池塘更可能是生命发源地
are a more likely place for the origin of life than ponds at the surface.
但是这项研究发现
But this study suggests that
干湿循环是形成RNA聚合物必不可少的条件
those wet and dry cycles are essential to form RNA polymers,
所以生命起源不可能发生在海底
so it couldn’t happen at the bottom of the ocean.
达尔文的这句话在科学界仍然很有分量
And Darwin’s delightful phrase continues to bear scientific weight.
在现代众多生物化学新闻中
In much more modern biochemistry news,
科学家研究给糖尿病人提供更多胰岛素的方法
scientists are looking into ways to supply diabetes patients with more insulin.
一个来自纽约西奈山医院的国际研究小组
An international team of researchers based out of Mount Sinai Hospital in New York
本周报道 他们在研究一项意想不到的来源 肿瘤
reported this week that they’re looking into an unexpected source: tumors.
我们倾向于把肿瘤和癌症相提并论
We tend to conflate tumors with cancer
并且认为它们一直对人有害
and believe that they’re always bad.
但根据化学观点来看
But in medical terms,a tumor is
肿瘤是一团细胞或其他物质比如液体
a mass of cells or other stuff like fluid
肿瘤会因多种原因突然出现
that can pop up for a number of reasons.
有时我们身体长出的肿块没有什么害处
Sometimes our bodies just develop lumps that are basically harmless.
胰岛瘤是一种罕见的几乎无害的肿瘤
One rare kind of mostly harmless tumor is an insulinoma,
它由胰腺β细胞形成
formed by pancreatic beta cells.
这些细胞产生胰岛素
These cells produce the insulin
它让细胞存储葡萄糖或将葡萄糖转化成能量
your body uses to manage blood sugar,
身体以此来调节血糖
by instructing cells to store glucose or convert it into energy.
患有胰岛瘤的人可能有低血糖的症状
Someone with an insulinoma might experience symptoms of low blood sugar,
但通常一次外科手术取出肿瘤 症状就会消失
but a surgeon can usually nip the tumor out, and the symptoms go away.
此外 胰岛瘤不会扩散
Plus, insulinomas don’t tend to spread,
所以它们不被认为是癌类或者非常危险
so they’re not considered cancerous or very dangerous.
癌症研究人员通常将它们作为低级优先目标
So they’re usually low-priority targets for cancer researchers.
但在生活中 有人需要更多的胰岛素
But there are people who could really use more insulin in their lives.
不管是糖尿病Ⅰ型还是Ⅱ型的患者
Both type 1 and type 2 diabetes patients
都不能从他们的胰腺获得足够需要的胰岛素
can fail to get as much insulin as they need from their pancreas.
研究人员还没有办法使用药物或治疗方法
And researchers have had very little luck so far using drugs or other treatments
让成人的胰腺β细胞提高胰岛素产量
to convince adult beta cells to up their insulin output or divide.
西奈山小组指出 糖尿病患者
The Mount Sinai team figured diabetes patients
和产生过多胰岛素的肿瘤完美匹配
and a too-much-insulin tumor were a perfect match.
所以他们收集了38种胰岛瘤
So they collected 38 insulinomas
分析那些肿瘤表达出来的基因
and analyzed the genes those tumors expressed.
然后 他们将那些基因表达模型与正常β细胞相比
Then, they compared that pattern of gene expression to normal beta cells,
因为胰岛瘤里的不同成份可能会促使β细胞增生
because what’s different in the insulinomas is probably driving those cells to grow.
该小组先前研究鉴定出β细胞的一种生长途径
The team’s previous research identified a growth pathway in beta cells
可以用名叫肉叶芸香碱的药物激活它
that could be turned on using a drug called harmine,
这是一种自然产生的作用于神经的化合物
which is a naturally occurring psychoactive compound.
新的研究揭示了β细胞的遗传途径 以及其他东西
That genetic pathway showed up in the new research, but so did others.
由于在胰岛瘤之间有众多的遗传变异
And while there was a lot of genetic variation between insulinomas,
这种肿瘤多数会在基因上发生变化
many of the tumors showed changes in genes that
从而调节其他基因的表达
modulate the expression of other genes—
包括著名的EZH2基因
including a well-known gene called EZH2,
EZH2基因会促进早期的肿瘤发展
which has roles in early development.
所以 可能有另外的方法
So there might be other ways
来刺激糖尿病患者体内β细胞的生长
to encourage beta cells to grow in diabetes patients,
科学家已经发现新的基因靶向药物
and scientists have new genes to target with drugs.
研究某些怪异 稀有的肿瘤真是件很酷的事
Which is a pretty cool thing to learn from some weird, rare tumors!
感谢收看本期的SciShow新闻
Thanks for watching this episode of SciShow News!
在你离开之前
And before you move on to another video,
能花点点时间填写一份我们的调查吗
could you take a second to fill out a survey for us?
显然 没有你的收看 就没有SciShow的存在
SciShow wouldn’t exist, obviously, without you watching,
所以我们希望能更多的了解你
so we want to learn more about who you are,
关于这些视频 你喜欢什么
what you like about these videos,
你希望从我们这里了解到什么
what you want from us!
说明里有一个链接 你可以点进去填写调查
There is a link in the description for you to click on and fill that out.
我们真心希望对你有更多的了解
We would really, very much appreciate learning more about who you are!
如果你想了解更多关于地球的早期生命
And also if learning more about early life on Earth is your jam,
查找我们新制作的一个节目 叫做Eons(永世)
check out a new show we’re doing called Eons
在youtube.com/eons上
at youtube.com/eons,
收看更多诸如此类的资源
for more of that stuff and for more of this.
我们一直在YouTube.com/scishow
We’re always at youtube.com/scishow.
[结尾曲]
[OUTRO ♪]

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视频概述

最新的科学研究综合生物化学以及天体物理学,设计出地球诞生之初的模型,模拟出生命诞生需要的条件。那么生命究竟来自哪里?希望你能从本视频中找到答案。

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视频来源

https://www.youtube.com/watch?v=cf_ELYttNYQ

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