缓步动物几乎坚不可摧的4个原因

缓步动物几乎坚不可摧的4个原因

Tardigrades are microscopic animals blessed with two very cool nicknames — the water bear and the moss piglet. They are segmented and reach a maximum length of a millimeter, maybe a millimeter and a half.

缓步动物是显微镜下的动物，它们有两个非常酷的绰号——水熊和苔藓小猪。它们被分割，最大长度为一毫米，也许是一毫米半。

Water bears are as seemingly indestructible as they are tiny. They've been known to survive in extreme temperatures, though there are limits. (We'll get to that in a minute.) They shrug off extreme doses of radiation and laugh in the face of the silent vacuum of space itself. In one experiment, water bears were exposed to outer space for 10 days. After returning to Earth, it was discovered that many of the bears had survived and some even had babies.

水熊看起来是坚不可摧的，因为它们很小。它们能在极端的温度下生存，虽然也有极限。(我们马上就会讲到。)它们对高剂量的辐射一笑置之，对空间本身的寂静真空一笑置之。在一项实验中，水熊暴露在外太空10天。回到地球后，人们发现许多北极熊幸存了下来，有些甚至还生了孩子。

Tardigrades can survive temperature extremes, space and even radiation. (Photo: Schokraie E, Warnken U, Hotz-Wagenblatt A, Grohme MA, Hengherr S, et al. (2012) [CC BY 2.5]/Wikimedia Commons)

Scientists even tried to rid the planet of tardigrades (only in theory) by putting the creatures through a series of tests that mimicked what they would experience if a deadly asteroid or radiation burst hit the Earth. But the tardigrades shrugged that off, too, outlasting billions of years worth of theoretic disaster events, according to a study published in the journal Scientific Reports.

科学家们甚至试图通过让这些生物进行一系列测试，模拟它们在致命的小行星或辐射爆发袭击地球时的感受，从而(仅在理论上)消除地球上的缓步动物。但根据发表在《科学报告》杂志上的一项研究，这些缓步动物也对这种说法不屑一顾，它们经历了数十亿年的理论灾难事件。

They may be alive on the moon

它们可能在月球上还活着

The moon has craters and mountains and other nooks and crannies where tardigrades could survive. (Photo: NASA's Goddard Space Flight Center Scientific Visualization Studio [CC BY 2.0]/Flickr)

Most recently, the little-water-bears-that-could caught our attention because they were revealed to be the only possible survivors from a 2019 crash landing on the moon. Luckily, the Israeli Beresheet probe didn't have any other living cargo on board when it crashed in April — a failed attempt to become the first private spacecraft to land on the moon.

最近，这些小水熊引起了我们的注意，因为它们被发现是2019年月球撞击事件中唯一可能的幸存者。幸运的是，今年4月坠毁的以色列“贝雷希特”号探测器上没有其他任何活着的货物。这架探测器试图成为第一个登上月球的私人宇宙飞船，但以失败告终。

However, a few thousand of the creatures were onboard at the time. They were part of a tiny lunar library put together by the Arch Mission Foundation, a group whose goal is to find a backup for Earth. The library consisted of the tardigrades, 30 million pages of information and human DNA samples.

然而，当时船上有几千只这种生物。它们是由Arch任务基金会建立的小型月球图书馆的一部分，该基金会的目标是为地球找到一个备份。图书馆包括缓步动物，3000万页的信息和人类DNA样本。

They can survive without water

没有水它们也能生存

Despite their nickname, water bears can go without water for about 10 years, living as a dried-out shell. For 250 years, we had no idea how these tiny creatures survived this extreme drying out, but a group of researchers from University of North Carolina at Chapel Hill discovered an answer.

尽管它们外号是水熊，但它们可以在没有水的情况下生活大约10年，就像一个干涸的壳一样。250年来，我们一直不知道这些微小的生物是如何在极度干燥的环境下生存下来的，但来自北卡罗来纳大学教堂山分校的一组研究人员找到了答案。

Researchers dried out tardigrades to see which genes turned on as a response to the stress, according to their study published in Molecular Cell. Researchers found that intrinsically disordered proteins (IDPs) kicked into gear, filling up the tardigrades' cells with an "amorphous matrix" that prevents them from going completely dry and dying.

根据发表在《分子细胞》杂志上的研究，研究人员将缓步动物晒干，看看哪些基因会对压力做出反应。研究人员发现，内在无序的蛋白质(IDPs)发挥了作用，用一种“无定形基质”填充缓步动物的细胞，防止它们完全干燥和死亡。

They can shrug off extreme temperatures, but ...

它们可以不在乎极端的温度，但是……

Mount Vinson is Antarctica's highest peak — and a likely home for tardigrades, which can live just about anywhere. (Photo: Wayne Morris/Shutterstock)

As mentioned earlier, these microscopic creatures that live on lichen and moss don't skip a beat when faced with cold temperatures. According to Smithsonian, they can survive extreme temperatures, frozen at minus 328 degrees Fahrenheit (minus 200 degrees Celsius) or heated to more than 300 degrees Fahrenheit (roughly 149 C). As with the other catastrophic conditions already mentioned, the secret is that under unfavorable conditions, they go into a state of suspended animation called the "tun" state. As a result, they can live almost anywhere, from Antarctica to the rainforest.

如前所述，这些以地衣和苔藓为食的微生物在面对低温时不会停止跳动。根据史密森学会的说法,它们可以生存的极端温度,在- 328华氏度(- 200摄氏度)或加热到超过300华氏度(约149摄氏度),正如前面提到的其他灾难性条件一样，秘密在于，在不利的条件下，它们进入一种被称为“TUN”状态的暂停动画状态。因此，它们几乎可以生活在任何地方，从南极洲到热带雨林。

They can resist radiation

它们能抵抗辐射

Humans are getting a lot more medical imaging tests these days, and perhaps tardigrades can teach us how to do it in the safest manner possible. (Photo: eAlisa/Shutterstock)

It was a team of Japanese researchers who figured out the secret behind the hardy critter's amazing defense against radiation. (Other researchers learned that one group of water bears could survive radiation doses of 5,000 to 6,000 grays, or absorbed energy per unit mass of tissue. In contrast, humans would barely survive a dose of 5 grays!) Among the animal's many coping strategies is a protein that protects its DNA from radiation damage. The researchers named it "Dsup" (short for "damage suppressor"). When the scientists transplanted the Dsup protein into human cells in the lab, it protected those cells, too.

是一组日本研究人员发现了这种顽强的生物惊人的防辐射能力背后的秘密。(其他研究人员了解到，一组水熊可以承受5000到6000灰的辐射剂量，或单位质量组织吸收的能量。相比之下，人类仅能在5个灰人的剂量下存活。这种动物的许多应对策略之一是一种保护DNA不受辐射伤害的蛋白质。研究人员将其命名为“Dsup”(损害抑制剂的缩写)。当科学家们在实验室中将Dsup蛋白移植到人类细胞中时，它也保护了这些细胞。