英國作家道格拉斯·亞當斯所寫的系列科幻小說《銀河便車指南》裡面提到
"生命，宇宙及萬事萬物的終極答案 -42 "
在故事中，一個具有高度智慧的跨維度生物種族為了找出一個能夠回答終極問題的簡單答
案，特別造了一臺超級電腦——「深思」（Deep Thought）來進行計算。「深思」花了
750萬年來計算和驗證，最後得出了「42」這個答案。
結果最近科學家發現這答案還真的是 42 !!!!!
http://www.sciencealert.com/simple-cell-has-42-million-protein-molecules-life-universe-everything
縮網址 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.