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偷天换日、就地取材:生命永不停歇...

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发表于 2018-3-6 07:10 | 显示全部楼层 |阅读模式
From stealing genes to regrowing limbs, how life finds a way to survive and thrive | Science | AAAS(偷盗基因至再生肢体,生命总有办法生存与绽放)
作者:Science News团队,  2018 -03-1, 2:00 PM
  https://www.sciencemag.org/news/ ... _2018-03-02&et_rid=290386097&et_cid=、1884186


Nature has a lot to teach us. As part of our special package, we explored how animals, plants, and bacteria use different resilience strategies when faced with scarce resources, predators, and other challenges.

Resilience by regeneration
Humans should envy the axolotl (pictured, above). Our powers of regeneration are limited: Broken bones knit, wounds heal, and large parts of the liver can regenerate, but that's about it. But the axolotl—a large salamander also called the Mexican walking fish because it looks like a 20-centimeter eel with stumpy legs—can replace an entire missing limb or even its tail, which means regrowing the spinal cord, backbone, and muscles. About 30 research teams are probing how these salamanders do it. In the axolotl, they've found, various tissues work together to detect limb loss and coordinate regrowth. In the process, the animals reactivate the same genetic circuits that guided the formation of those structures during embryonic development, causing generalist stem cells to specialize.

Axolotls are only one of several regenerators in the animal kingdom. Flatworms called planarians are even more resilient—able to surge back after losing 90% of their bodies. One small fragment of those 2-centimeter-long aquatic worms can rejuvenate the brain, skin, gut, and all the other functional organs. Again, stem cells are key, and a special set of genes active in muscles tells those stem cells what to do, activating growth and specialization genes in the right cells at the right time. So the planarian can rebuild itself almost from scratch, whereas the axolotl can rebuild only if the main body axis is intact. This year, researchers took another step toward detailing the molecules underlying regeneration by sequencing the genomes of those two species. The ultimate hope: One day, we'll be able to coax injured humans to execute the same repairs. —Elizabeth Pennisi


Stealing genes to survive
Imagine a raging infection in the lungs of a hospitalized cancer patient. When a powerful antibiotic floods the patient's system, the bacterium responsible, Klebsiella pneumoniae (pictured), seems to be doomed. But it can deploy a resilience strategy honed over billions of years: borrowing a gene from another cell that enables the pathogen to survive.

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 楼主| 发表于 2018-3-31 08:20 | 显示全部楼层
本帖最后由 imvivi001 于 2018-3-31 08:31 编辑

意识能永生吗?----未来大脑或以数字形式再次“复活”新浪科技 2018-03-30  13:00



近期,有国外媒体报道,一家名为 Nectome 的美国创业公司计划对人的活体大脑进行保存,并在未来实现意识上传。令人感到可怕的是,保存大脑的过程需要在人还未死亡时进行,以获取新鲜的大脑,这也意味着想完成意识上传,需要经历特殊的“安乐si”过程。目前,已有25人缴纳了1万美元订金,进入“等待名单”。
图片来源:Nectome.com


“致力于存档你的思想”,这是Nectome的使命,赫然写在官方网站的首页。如果一切都按完美的计划进行,人们的大脑在经过该公司处理后,最终会以数字形式再次“复活”。

   

    Nectome对于未来实现“意识上传”的信心一部分来源于其联合创始人Robert McIntyre与其他研究人员一起开发的新技术,一种被称为ASC(Aldehyde-Stabilized Cryopreservation)的低温保存技术。
这项技术让他们获得由大脑保存基金会颁发的两个奖项,“小型哺ru 动物大脑保存奖”以及“大型哺ru 动物大脑保存奖。”大脑保存基金会(The Brain Preservation Foundation)称,利用ASC技术首次实现了大型哺ru 动物大脑连接组可达数百年之久的保存。他们认为大脑连接组可以解码一个人全部知识,虽然目前这在大多数科学家眼中更多的是一种猜测。
 楼主| 发表于 2018-3-31 08:33 | 显示全部楼层
Nectome公司所使用的大脑保存技术被称为ASC,在其网站上,nectome对这一技术进行了简要介绍,被称为“固定化”(fixation),他们使用化学物质戊二醛,可以快速固化突触,防止其受损,这种方法已经使用了几十年来保存生物样本,包括大脑、各种器官甚至整个动物。

    当大脑被戊二醇充分固化后,它可以保存数周、数月甚至一两年,但大脑仍然会缓慢降解,无法实现数百年的无损保存。为了解决这个问题,Nectome提出使用极低温将存储时间延长至数百年时间。为了防止在低温存储时产生冰晶,破坏细胞,他们还需要在生物体内灌注乙二醇,随着温度的降低,含有乙二醇的生物溶液会越来越粘稠,直到它变成玻璃状固体。

    使用ASC技术,Nectome公司的联合创始人Robert McIntyre已经与其它研究人员一起,完成了小型哺乳动物兔子和大型哺乳动物动物猪的大脑保存。据MIT Technology Review报道,由于大脑保存得极其完好,每一个突触在电镜下都清晰可见。

     现在Nectome希望将这个技术拓展到人的大脑保存,不过身体健康的人并不在他们执行服务范围之内。因为最终目标是“意识上传”,所以他们需要保存的是新鲜的大脑,但这又必然导致死亡,因此这项服务只有当人处于生命终末期时才能够执行,而且需要在允许物理辅助zi杀的地方,否则将是违法的行为。

当一个处于生命终末期的人接受大脑保存服务时,Nectome会将患者与一台心肺仪器相连接,将特定的化学溶液从颈动脉泵入体内。

     在Nectome看来,将大脑完美的保存是意识上传的第一步,接下来,他们需要等待科学技术的进一步发展,再将大脑中保存的感觉、知识等一切信息变为数字化的存在,实现意识上传,人的“重生”。
发表于 2018-4-3 18:41 | 显示全部楼层
嗯,再发射到太空去,说不定碰到三体人就可以完美复活了。
 楼主| 发表于 2018-4-4 13:24 | 显示全部楼层
对三体人不能抱太多美好的期望
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