Benjamin Nettersheim, a geobiologist at the University of Bremen in Germany, Jochen Brocks, a palaeobiogeochemist at the Australian National University in Canberra, and their colleagues decided to focus on short-lived molecules that modern eukaryotes make while synthesizing sterols.

德国不莱梅大学生学家本杰明·内特谢姆、澳大利亚国立大学堪培拉分校古生化学家约翰·布洛克斯及其同事决定将重点放在现代真核生合成类醇时产生短寿命分子上。

This absence has led to speculation that before 800 million years ago, eukaryotes were not abundant enough to leave a detectable sterol trace.

这种缺乏导了一种猜测，即在8亿年前之前，真核生并不足以留下可检测到类醇痕迹。

Most modern eukaryotes rely on fat-like compounds called sterols, such as cholesterol, to build cell membranes and carry out other cellular functions.

大多数现代真核生依靠类似脂醇类化合（如胆醇）来构建细胞膜并执行其他细胞功能。

One possibility is that eukaryotes that make more-modern sterols gained a selective advantage between one billion and 800 million years ago, eventually displacing their protosterol-making counterparts.

可能一种可能性是，在10亿到8亿年前，制造现代醇真核生获得了选择性优势，最终取代了它们制造原始醇同类。

That would suggest that modern sterols — not just their precursors — should also be present in rocks that are more than 800 million years old.

这表明现代醇——不仅仅是它们前身——也应该存在于超过8亿年历史岩石中。

Because sterols are found throughout the eukaryotic family tree, they are thought to have been present in the last common ancestor of all modern eukaryotes.

由于类醇在真核生系谱中随处可见，因此人们认为它们存在于所有现代真核生最后一个共同祖先中。

They maybe hard to make sterol, which is important for medical uses and they tend to be weak.

它们可能很难制造甾醇，这对医疗用途很重要，而且它们往往很弱。

It contains sterol esters from soybeans. Take Control is one of two food products designed to reduce cholesterol.

它含有来自大豆植甾醇酯。Take Control是两款旨在降低胆醇食产品之一。