英国作家道格拉斯·亚当斯所写的系列科幻小说《银河便车指南》里面提到
"生命，宇宙及万事万物的终极答案 -42 "
在故事中，一个具有高度智慧的跨维度生物种族为了找出一个能够回答终极问题的简单答
案，特别造了一台超级电脑——“深思”（Deep Thought）来进行计算。“深思”花了
750万年来计算和验证，最后得出了“42”这个答案。
结果最近科学家发现这答案还真的是 42 !!!!!
http://www.sciencealert.com/simple-cell-has-42-million-protein-molecules-life-universe-everything
缩网址 https://goo.gl/SytHiJ
Scientists Counted All The Protein Molecules in a Cell And The Answer Really
Is 42
This is so perfect.
SIGNE DEAN 23 JAN 2018
Biologists have served up the answer to the ultimate question of life, the
Universe, and everything.
That answer, as you may know, is 42. And the question, in this case, is "how
many million protein molecules are there in a single cell?"
Given that cells are the basic structural units of all living organisms we
know of, the team at the University of Toronto in Canada really couldn't have
arrived at a more fitting number - but they didn't set out to verify the
fancies of Douglas Adams.
Proteins are the molecules doing the majority of heavy lifting within our
cells, and their activity is what determines how well our cells function and
communicate with each other.
On top of that, a cell's proteome - the complete collection of proteins
within the cell - is highly dynamic, constantly being affected by
environmental changes and stresses.
Given the proteins' fundamental importance, it's no surprise that biologists
need to know how many proteins there are, if they're going to have a complete
understanding of what really goes on inside a cell.
But the difficulty in pinning down a good number for protein abundance comes
down to the different methods and arbitrary measurement units scientists have
used over the years.
"Despite the comprehensive nature of existing protein abundance studies, it
remains difficult to ascertain whether a given protein abundance from any
individual study, independent of other abundance studies, is reliable and
accurate," the team writes in their paper.
The study looked at data from 21 separate analyses measuring the amount of
proteins in Saccharomyces cerevisiae, a single-cell yeast species that serves
as one of the classic model organisms in cellular biology.
With so many datasets, the researchers jumped at the opportunity to put
together a comprehensive analysis - although they had to convert all the data
to one measurement first.
"It was hard to conceptualise how many proteins there are in the cell because
the data was reported on drastically different scales," says one of the team,
graduate student Brandon Ho.
The team settled on the amount of molecules per cell as being the "most
intuitive expression of protein abundance", and got to work normalising the
data and matching up those vastly different scales.
S. cerevisiae is currently estimated to have a proteome of 5,858 proteins,
and the team was able to determine that in an average yeast cell the
molecules of these proteins would amount to 4.2 x 10^7 - or 42 million.
The abundance of these proteins is not evenly distributed, however. Most of
the types of proteins in the yeast cell will have somewhere between 1,000 and
10,000 molecules, a few will only be represented by a handful, and yet some
others could measure as many as half a million.
Not only do researchers now have a reliable number for protein abundance in
yeast, but the methods they've devised in this study could even help us do
similar studies on human cell proteomes in the future.
Given that a whole range of human diseases, including Alzheimer's and ALS,
involve abnormal functioning of our cells' proteins, it's great to make
headway in finding out more about these crucial little molecules.
The study has been published in Cell Systems.