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Mathematical modeling can seem like maybe a dry profession,
but when you get to pull in findings from a half dozen different fields,
the results can be especially awesome.
Like, a paper published this week by a team of scientists in Canada and Germany
confirming a piece of speculation going all the way back to Darwin.
This research suggests that the Earth’s biochemistry could've originated
in warm ponds on newly formed continents between 4.5 and 3.7 billion years ago,
with the help of meteor strikes that used to rock the planet.
And it supports the hypothesis that the earliest biochemical processes
centered around ribonucleic acid, or RNA.
For this paper, the team constructed a detailed mathematical model
of the conditions of early Earth, and filled that model with small ponds.
The ponds were small enough that they would sometimes dry out in seasonal cycles.
Their model accounted for meteorites supplying some raw materials
for chemical reactions, like nucleobases,
which are some of the building blocks of DNA and RNA.
Previous research has found that nucleobases can actually be formed
in space, and we’ve found them in meteorites before.
But for those nucleobases to do anything life-wise,
they have to come together in a chemical chain, or polymer.
The team’s model found that if the ponds were able to dry out periodically,
the evaporation and precipitation cycles created the right conditions
for RNA polymers to form and remain fairly stable.
Other lab studies have suggested that a hot and dry step could
concentrate the ingredients and encourage the reactions that form the polymer bonds.
And then adding water gives everything a good mix to bring in more chemical components.
In cells like ours, RNA acts as a go-between for DNA and protein.
Plus it makes up some of the most ancient cellular structures, like ribosomes.
So some researchers hypothesize that RNA used to fulfill the roles
of genetic code and biological machinery—
until more stable, more flexible DNA and protein took on those jobs.
This team pieced together prior research from fields as diverse as
chemistry and astrophysics to do a calculation no one’s ever done before
about the state of the early Earth, although these ideas
have been floating around for a while.
The phrase “warm little pond” was actually coined by Charles Darwin,
who imagined a place with plenty of nutrients and energy
for the chemical origins of life, and while Darwin was no biochemist,
the idea has held up.
In recent decades, some have argued that deep sea hydrothermal vents
are a more likely place for the origin of life than ponds at the surface.
But this study suggests that those wet and dry cycles are essential to form RNA polymers,
so it couldn’t happen at the bottom of the ocean.
And Darwin’s delightful phrase continues to bear scientific weight.
In much more modern biochemistry news,
scientists are looking into ways to supply diabetes patients with more insulin.
An international team of researchers based out of Mount Sinai Hospital in New York
reported this week that they’re looking into an unexpected source: tumors.
We tend to conflate tumors with cancer and believe that they’re always bad.
But in medical terms, a tumor is a mass of cells or other stuff like fluid
that can pop up for a number of reasons.
Sometimes our bodies just develop lumps that are basically harmless.
One rare kind of mostly harmless tumor is an insulinoma,
formed by pancreatic beta cells.
These cells produce the insulin your body uses to manage blood sugar,
by instructing cells to store glucose or convert it into energy.
Someone with an insulinoma might experience symptoms of low blood sugar,
but a surgeon can usually nip the tumor out, and the symptoms go away.
Plus, insulinomas don’t tend to spread,
so they’re not considered cancerous or very dangerous.
So they’re usually low-priority targets for cancer researchers.
But there are people who could really use more insulin in their lives.
Both type 1 and type 2 diabetes patients
can fail to get as much insulin as they need from their pancreas.
And researchers have had very little luck so far using drugs or other treatments
to convince adult beta cells to up their insulin output or divide.
The Mount Sinai team figured diabetes patients
and a too-much-insulin tumor were a perfect match.
So they collected 38 insulinomas and analyzed the genes those tumors expressed.
Then, they compared that pattern of gene expression to normal beta cells,
because what’s different in the insulinomas is probably driving those cells to grow.
The team’s previous research identified a growth pathway in beta cells
that could be turned on using a drug called harmine,
which is a naturally occurring psychoactive compound.
That genetic pathway showed up in the new research, but so did others.
And while there was a lot of genetic variation between insulinomas,
many of the tumors showed changes in genes that
modulate the expression of other genes—
including a well-known gene called EZH2, which has roles in early development.
So there might be other ways to encourage beta cells to grow in diabetes patients,
and scientists have new genes to target with drugs.
Which is a pretty cool thing to learn from some weird, rare tumors!
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