科学美国人60秒:Microbe Breaks the Powerhouse Rules

If you were searching for a lifeform unlike anything known to science, where would you look? Scientists at Charles University, in Prague, looked in the poop of a pet chinchilla. "They were isolating a lot of various strains from various environments—including their own pets." Anna Karnkowska, an evolutionary biologist who collaborated on the work, who is now at the University of British Columbia. "Scientists like to isolate things from everywhere possible."
如果你在寻找科学中尚不熟悉的生命，那去哪里寻找?查理大学的科学家们研究了宠物南美栗鼠的大便。“他们隔绝了环境中的不同的细菌——其中包括自身宠物的细菌。” 来自英属哥伦比亚大学的

Anna Karnkowska也是负责该工作的进化生物学家。“科学家们喜欢尽可能地隔绝一切外界的事物。”
They found a relative of the parasite Giardia, called Monocercomonoides. It’s eukaryotic, meaning it has organelles and a nucleus enveloping its DNA. Just like our cells, or the ones in plants, or fungi. But unlike bacteria, which don’t have those things.
他们发现了一种贾第鞭毛虫的亲戚，Monocercomonoides。这是一种真核细菌，这意味着该细菌的细胞核包围着其DNA。这就像我们的细胞，或者植物、真菌中的细胞。但是其他的细菌仅是拥有裸露的DNA。

And upon closer examination, the new critter was different from every other eukaryote known to science. Because it’s missing a key organelle—it seems to have no mitochondria.
经过细致的检测，这种新的生物与科学界中已知的其他真核细胞不同。因为这种生物似乎没有关键的细胞器——线粒体。

You probably learned in biology class that mitochondria, let’s all say it together, are the powerhouses of the cell. They charge up energy-rich molecules, when oxygen's around. But they do other stuff too: like manufacture certain essential proteins. This newly discovered microbe, and others that live in low-oxygen environments, use different, oxygen-free pathways to make energy.
在生物课上，你可能学过，细胞的能量来源是线粒体。当氧气充足的时候，线粒体会为分子提供丰富的能量。但是线粒体也有其他的功能，如制造某些必要的蛋白质。这种新发现的微生物，以及依靠氧气生存的其他的微生物，利用不同的途径利用游离氧气来制造能量。

But they usually still have mitochondria for that protein assembly job. The new bug apparently pulls off the protein-synthesis by using a system that it picked up from bacteria, in what’s known as a lateral gene transfer. The findings are in the journal Current Biology.
但是，这些生物中的一些线粒体也负责蛋白质的组装工作。很显然这种新的微生物通过从细菌中沿袭的一些系统来合成蛋白质，这也就所谓的横向基因转移。该研究结果发表在《当代生物学》杂志上。

Karnkowska says the microbe's ancestors probably had mitochondria at some point—then lost them once they’d acquired the bacterial system. And she says other microbes might share a similar story. "We know now that probably there are more of these weird things." And as this study suggests, they could be found in some weird places.
Karnkowska 表示这些微生物的祖先可能曾经也有线粒体——但是之后，在获得了细菌系统之后，这些细菌就丢失了线粒体。她还表示，其他的微生物可能也有类似的情况。“现在，我们知道可能有非常多的奇异的事情。”并且，这项研究还表明，这些事情可能会出现在一些奇怪的地方。