A new microscope

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A new microscope is giving researchers an unprecedented view of how mammals are built, cell by cell.一种新型显微镜让研究人员对哺乳动物是如何一个细胞一个细胞地构建的有了前所未有的认识。

Light sheet microscopes use ultrathin laser beams to illuminate sections of a specimen while cameras record those lit-up sections.光板显微镜使用超薄激光束照亮标本的部分，而摄像机则记录下那些隆起的部分。 Previous iterations of the device have captured detailed portraits of living zebra fish and fruit fly embryos as they develop.该装置的前几次迭代捕捉到了斑马鱼和果蝇胚胎发育时的详细照片 Kate McDole, a developmental biologist at Howard Hughes Medical Institute’s Janelia Research Campus in Ashburn, Va., and colleagues used a new-and-improved version to monitor the development of a larger, more complex organism: the mouse.

Algorithms in the microscope tracked six-day-old mouse embryos in real time over roughly two days, keeping the device focused on the cell clusters as they grew.显微镜中的算法在大约两天的时间里实时跟踪了六日大的老鼠胚胎，使该设备在它们成长的过程中聚焦于细胞群A suite of computer programs used the data — about a million images per embryo — to map the life history of each embryo’s every cell, the team reports October 11 in Cell. The result: dazzling views of mouse organs taking shape.结果是:老鼠的器官正在成形，令人眼花缭乱

As an embryo rapidly expands in size, the gut starts to form when part of the embryo collapses into a craterlike hole当胚胎迅速膨胀时，当部分胚胎坍缩成一个类似火山口的洞时，肠道就开始形成. And a structure that eventually forms the brain and spinal cord, called a neural tube, appears like a comet shooting across the night sky.一种最终形成大脑和脊髓的结构，叫做神经管，看起来像彗星划过夜空。 Researchers also captured the first beats of heart cells.

GROWTH SPURT Scientists used a new laser-powered microscope to peek inside a growing mouse embryo (shown in false color in the first clip). Over two days, the team saw the formation of the mouse’s gut (dark blue hole that appears in the developing embryo) and neural tube (white line), which becomes the brain and spinal cord. Probing deeper into the embryo revealed newly developed heart cells’ first rhythmic beats (second clip).

“These are processes no one has been able to watch before,” McDole says. Seeing the gut form in minutes was stunning. “We never expected it to be that fast or that dramatic. It’s not like you can Google these things.”。在几分钟内就能看到它的内脏形态是令人震惊的。“我们从没想过它会这么快这么戏剧化。你不可能做到这些

Such imaging technology may help resolve a long-standing mystery: how mammals develop from single cells to fully formed multicellular embryos. That information is crucial for scientists attempting to grow human organs (SN: 3/6/04, p. 155) or fix defects that arise in embryos during pregnancy,修复怀孕期间胚胎产生的缺陷， McDole says.

“If you took all the building materials for a house and threw them in a pile, you don’t magically get a house. Contractors use plans to build the house,” she says. The same thing applies to human health, she says, so “being able to see how embryos actually make organs is a huge step forward.”

Citations

K. McDole et al. In toto imaging and reconstruction of post-implantation mouse development at the single-cell level. Cell. Published online October 11, 2018. doi:10.1016/j.cell.2018.09.031.