在加拿大
How Coronavirus Tests Actually Work
The coronavirus crisis is in large part a testing crisis. We are reading about tests. Arguing about tests. And, in many cases, struggling mightily to obtain tes…
fivethirtyeight.com
冠状病毒危机在很大程度上是测试危机。 我们正在阅读有关测试的信息。 关于测试的争论。 并且，在许多情况下，竭尽全力为自己获得测试。 但是，尽管测试短缺成为头条新闻，但这些测试背后的技术仍有很多尚未为公众所了解。 就像我们都在其中的一场真人秀中一样，您同意与一个陌生人结婚，与一个无法从人群中挑选出来的人建立高风险的关系。因此，让我们更加了解我们无法停止谈论的测试。 至少，对COVID-19的测试有更多的了解会帮助您了解为什么在需要时很难获得它。 首先，医务人员将拭子（一个超长的单头Q型尖头）向上，向上，向鼻子上方推。它捕获了病毒颗粒，以及一堆其他的东西，如加利福尼亚大学圣地亚哥分校的研究病毒学家戴维·史密斯博士，被称为“生物垃圾”，例如粘液和随机细胞。史密斯说，下一步是分离病毒RNA，即病毒用来自我复制的遗传物质。像导致COVID-19的病毒一样，RNA中的RNA与DNA类似，但它不是中间部分的一半，而是双螺旋的扭曲阶梯。有些病毒以DNA的形式携带其遗传密码，但RNA病毒的突变速度更快。该功能可帮助他们跳出物种，并逃避自然和医学努力来杀死它们。例如，流感的突变如此之快，以至于我们每年都需要一种新的疫苗。就像DNA可以识别一个人一样，RNA可以识别导致COVID-19的病毒。分离它需要一系列步骤-添加不同的化学物质，然后在离心机中反复旋转样品-旨在将样品分成多个层，如精美的鸡尾酒小球，其中包含RNA的层浮在顶部。然后必须进一步纯化RNA。分离RNA的方法不只一种，而且公司出售的试剂盒中包含了使它起作用所需的化学物质（称为试剂，因为它们被用来诱导化学反应）。 从那里开始，RNA与称为引物的DNA短片段混合。引物和RNA与DNA的松散构建基块，像基因构建人员一样起作用的酶以及更多的试剂结合在一起。混合全部，您的RNA就会变成DNA。最后，需要复制新的DNA，直到您有足够的DNA进行实际研究为止。那是另一种化学试剂盒–更多的引物，结构单元和试剂–一遍又一遍地进行基本上相当于生物复制粘贴的操作。这称为聚合酶链反应（PCR），此处使用的引物特别重要。这些复制引物基本上是您要寻找的病毒的片段，史密斯说，它将与该特定病毒的遗传物质结合，如果没有样品中的COVID-19，那么COVID-19引物就不会与之结合。复制任何DNA。史密斯说：“我们加入了一些特殊的染料，这样当它构建出我们想要的正确的DNA时，我们就能看到颜色在特殊的机器上亮起来。”如果您使用的是COVID-19，您的样品现在将显示带有新鲜构建的，色彩鲜艳的DNA来证明这一点。评论
分离出来RNA
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primer
A primer is a short nucleic acid sequence that provides a starting point for DNA synthesis.www.nature.com primer
A primer is a short nucleic acid sequence that provides a starting point for DNA synthesis. In living organisms, primers are short strands of RNA. A primer must be synthesized by an enzyme called primase, which is a type of RNA polymerase, before DNA replication can occur. The synthesis of a primer is necessary because the enzymes that synthesize DNA, which are called DNA polymerases, can only attach new DNA nucleotides to an existing strand of nucleotides. The primer therefore serves to prime and lay a foundation for DNA synthesis. The primers are removed before DNA replication is complete, and the gaps in the sequence are filled in with DNA by DNA polymerases. In the laboratory, scientists can design and synthesize DNA primers with specific sequences that bind to sequences in a single-stranded DNA molecule. These DNA primers are commonly used to perform the polymerase chain reaction to copy pieces of DNA or for DNA sequencing.评论
polymerase chain reaction (PCR) 这个东西很重要， 发明人得了1993年的诺贝尔奖
The Nobel Prize in Chemistry 1993
The Nobel Prize in Chemistry 1993 was awarded "for contributions to the developments of methods within DNA-based chemistry" jointly with one half to Kary B. Mullis "for his invention of the polymerase chain reaction (PCR) method" and with one half to Michael Smith "for his fundamental...
www.nobelprize.orgKary B. Mullis 
FactsThe Nobel Prize in Chemistry 1993 Born: 28 December 1944, Lenoir, NC, USA Died: 7 August 2019, Newport Beach, CA, USA Prize motivation: "for his invention of the polymerase chain reaction (PCR) method." Prize share: 1/2 Work An organism\'s genome is stored inside DNA molecules, but analyzing this genetic information requires quite a large amount of DNA. In 1985, Kary Mullis invented the process known as polymerase chain reaction (PCR), in which a small amount of DNA can be copied in large quantities over a short period of time. By applying heat, the DNA molecule\'s two strands are separated and the DNA building blocks that have been added are bonded to each strand. With the help of the enzyme DNA polymerase, new DNA chains are formed and the process can then be repeated. PCR has been of major importance in both medical research and forensic science.评论
赞大师学习精神
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You can check out anytime you like, but you can never leave. 赏 2020-03-26#6 B
无官一身轻
付费矿工 3$(0.00$赞力,#86) 15,327 $11.23 $2.57 谢谢科普，看着挺复杂的，难怪一测试难求。评论
看的有点晕...也点个