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Of all the cells in the human body, fat cells might get the most hate.
Their main function is to store fat molecules.
And while that is a very important job, a lot of people kinda maybe wish they didn’t
have quite so many.
But it turns out that fat cells, or adipocytes, are doing a lot for your body -- maybe even
more than scientists ever imagined.
Because this week, a trio of British biologists reported for the first time that fat cells
can move.
Oh, and also it turns out they help heal wounds.
The study, which was published this week in the journal Developmental Cell, was done on
fruit flies.
But the team thinks fat cells might do something similar in humans.
The researchers were interested in how fruit flies repair their wounds, and there were
some hints that fat cells could be involved — like weirdly big shadows that showed up
under a microscope.
For these experiments, they used lasers to make small wounds on the underside of fly
pupae — I know this seems kind of mean — that’s the stage just before the fly is fully grown.
And to keep track of which cells were fat cells and which were other types, they turned
them different colors.
Then they recorded what happened next under a microscope.
Almost immediately, large fat cells started traveling to the injured area to plug the
hole, usually taking about an hour to get there.
Then they basically turned into, like, a fat version of a band-aid, forming a tight seal
on the wound that would keep bacteria out.
The fat cells also worked with the flies’ immune system to remove dead cells and any
other debris that was hanging around.
And if the researchers infected the wound
on purpose, the fat cells released antimicrobial peptides, or small defense proteins, to fight
them off.
Seeing fat cells help heal wounds was weird enough.
But really, the strangest part was the fact that these cells were moving at all.
Researchers had always assumed fat cells kind of just sat there.
But here was a cell swooping in to save the day.
It gets even weirder, because the fat cells weren’t moving the way most cells in an
organism do, which is by sticking to other cells and tissues and kind of pulling themselves
along.
Instead, the fat cells seemed to be entirely on their own, changing their shape to propel
themselves through the flies’ liquidy insides.
Basically, they were swimming.
Now, the question is whether we also might have a bunch of Michael Phelps-like fat cells
in us that mobilize when we get hurt.
Obviously, there’s a lot going on in flies that’s different from humans.
We have much more complicated clotting systems, so it’s unlikely fat cells would serve the
exact same purpose in us as in flies.
And hopefully not too many of us are suffering from laser wounds.
But there’s some evidence that fat cells in mice also pump out these antimicrobial
defense proteins, which could bode well for us.
And frankly, no one has looked very hard to see whether any fat cells are moving.
So, it could be just a fly thing, but it might not be.
And maybe you should be thanking your fat cells, instead of wishing they were smaller
or less numerous.
Speaking of size:
In another paper published this week — this one in Nature Communications — a group of
French and Brazilian virologists reported discovering two new giant viruses.
Giant viruses are still microscopic.
You’re not going to spot any crawling around in your basement.
But compared to the rest of the viruses on the planet, these things are huge — they’re
more like the size of bacteria.
And so are their genomes!
Since both of the new viruses were found in Brazil, the researchers named them tupanviruses,
in honor of Tupã, the thunder god of a local indigenous group known as the Guaraní.
One came from the mud of a soda lake — a type of lake that’s super salty and has
a high pH.
So as tasty as it sounds, you probably don’t want to drink it unless you enjoy bleach with
a side of salt.
The other virus was found in deep ocean sediments off the coast of Rio de Janeiro, dug up by
a helpful submarine robot.
Under a microscope, the viruses look a bit like fuzzy light bulbs with extra long screw
sections.
They can grow to more than 2 microns, or millionths of a meter, making them one of the longest
viral particles on record.
Now, usually, viruses have just a handful of their own genes, because they mooch off
their hosts for everything else.
Influenza A, for instance, has just 8 genes, and HIV has 9.
Their entire genomes are made up of less than 15,000 nucleotide building blocks.
But these tupanviruses have genomes that are a hundred times bigger, with about 1.5 million
of those building blocks making up a whopping 1300-1400 genes.
Even more impressive is the content of those genes.
Tupanviruses have more genes dedicated to synthesizing and assembling proteins than
any virus we’ve ever seen, including roughly 200 other giant viruses.
Which is surprising, because part of what makes viruses dependent on other life forms
is the fact that they rely on their hosts for that very job.
Now, tupanviruses still can’t string proteins together on their own because they’re missing
a few key players.
But almost all the pieces are there.
The question is, where did this strange set of genes come from?
One possibility is that giant viruses started off as some kind of cell, and then lost some
genes over time to become a virus.
But it could also be that they started off as smaller viruses, and grew bigger as they
picked up genes from various hosts.
Scientists are hoping to figure out how giant viruses evolved by comparing their genomes
to other viruses and other organisms.
The tupanviruses give us a bunch of new data to add to the pile, but they aren’t enough
to give us the answer own their own.
We’ll need to find more giant viruses to figure out what really happened.
So here's to more digging!
About a year ago, we launched a new channel with the help and guidance of our SciShow
patrons: SciShow Psych.
Well, this coming Tuesday, SciShow Psych turns one-year-old and we would like to celebrate
with you.
As a thank-you to our patrons, we’ll be having a birthday livestream for SciShow Psych
on Tuesday, March 6 at 3pm ET.
I’ll be there, along with my co-host on SciShow Psych, Brit Garner, and a few of our
favorite behind the scenes folks as well.
And if you’re a SciShow patron, we hope you can be there too!
Watch for the link to the livestream on Patreon and we’ll see you then!
Bring your party poppers and your burning psych questions.
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