So a couple weeks ago, I went to visit
my friend Leslie in her lab to talk about my favorite model
organism fruit flies as well as her research involving
stem cells and guts and developmental biology and poop.
We also talked about poop.
It was great.
Let's go.
Come follow me.
So we keep flies in incubators.
So this is an example of an incubator.
And these are bottles.
So we keep flies either in vials or in bottles,
and the bottles just let a lot more flies grow.
One of the first questions I get asked whenever
someone who isn't a fly biologist comes into the lab
is how do you work with flies.
And so the way we work with flies is we use CO2.
And so this is-- basically it's a CO2 gun
that we use to shoot basically CO2 into the bottle.
And what it does is it knocks the flies out and keeps them
from moving so that we can work with them easier.
And then once we take them off the CO2, they'll wake up again.
So this is a fly pad.
So this also emits CO2 so that the flies will stay knocked out
even when they're on the pad.
And then we just use a paint brush to move them around
so we can see what's happening.
So what we're looking at now is fruit flies.
So these are the adult fruit flies.
So first of all, we can start off
by showing the different genders.
So the males are generally but not always smaller.
You can often tell by a lot of times the males have a darker
patch here whereas the females tend
to be a little bit lighter but not always.
Fruit flies start out their life as eggs.
And when those eggs hatch, they hatch his larvae,
and they crawl around in this food
down here and basically all they do is eat and poop and grow.
Great.
And then once they reach a certain size,
they start crawling up the side of the vial,
and they eventually will form a pupil case
and undergo metamorphosis like caterpillars
to butterflies where essentially the vast majority of the larva
will actually dissolve.
And those cells will eventually rearrange
to become an adult fruit fly like this guy right here.
I think what's really fascinating
about it is that you have basically this tube that all
it does is eat, and somehow in a lot of those cells
is some sort of information that will tell basically
this mishmash of cells how to become an adult fly, which
is externally a far more complicated organism
than the larva.
And so how that all happens is still
a lot of a bit of a black box in understanding
how those cells rearrange, which cells die, which cells divide
and things like that is something
that I think a lot of people are really interested in.
I think is a really cool area of study
and is very developmental biology.
Yes.
Developmental biology goes beyond just individual cells
and looks at how cells and communities work together
to build working, functioning animal or organism.
I study the intestine of fruit flies.
And for the gut, what this means is
that the larva, because basically it's just
an eating machine, has a gut, but once it enters the pupil
case, a new gut will actually start to form.
And the old gut, the cells will die off and compact,
and basically the first poop that the adult fly makes
is its old gut.
No way.
Yes.
Oh, my god.
That's both gross and amazing.
What's really cool is you can actually see that,
and so you can see that here.
So this is a really young female fly.
And this grayish greenish spot right
here is actually that is the gut that she is going to poop out.
And the fun fact that I love to share about guts in general is
that by this time next week , our human guts--
so your gut, my gut, everyone's gut--
will be lined almost entirely with brand new cells.
And so I think most people are--
come with the assumption that we are born with the cells that--
the cells that we have today are the cells
that we were born with, but that's actually not true.
The vast majority of the cells in your body
undergo what we called turnover, where cells are regularly
lost and replaced through just normal healthy growth
and processes.
What we're really interested in is how do--
what determines those turnover rates.
But also turnover happens because cells die,
and in most tissues, stem cells recognize
that cells are gone and will divide to replace those cells.
And so how do stem cells know that other cells in the tissue
are gone?
But also stem cells also have to be
able to tell which types of cells died.
So most of our tissues have a bunch
of different types of cells, and the stem cells
have to be able to know which cells to replace.
And so how does it make that decision of I
have to divide to replace the cell but also that cell--
what kind of cell should I be replacing.
On the outside flies are very, very different from humans,
but in a lot of ways, a lot of things that happen in flies
actually are very similar to the things that happen in humans
or higher level organisms.
We share a lot of really important genes
and actually a lot of factors that
have been discovered in flies have actually
been shown to also be important in humans and mammals.
And they're also really small.
They're easy to grow.
They reproduce really quickly.
And so you can do experiments a lot faster
and get them better understanding of how systems
work on a much shorter timescale than you would if you
were working, say, with mice.
I think the biggest reason that I love science,
I love being a scientist is that I
love being at the forefront of knowledge,
and I love being at that cliff's edge of we
don't know what's out there.
We don't know-- getting to answer questions
that no one has asked before or see things
that no one has seen before I think is really exciting.
Being able to basically come to work every day
and basically be that annoying kid that asks, well,
why does that happen, why does this happen, why does that
happen I think is really fun and is really exciting.
So most of the work that I do with flies
involves looking through a microscope
and looking through really powerful, really
expensive microscopes and being able to see in a certain sense
this whole new world that most people don't get to see.
And it's like my outer space or my 20,000 feet
under the ocean or whatever.
It's this whole other universe where the rules are just
very different, and it's very beautiful.
I was always really attracted to biology
because I've always been a very artsy and very visual
person and microscopy and being able to look
in microscopes in particular is just visually stunning.
And it's really exciting to be able to come
to work and be able to generate beautiful, meaningful pictures
about science and try to understand how the world works.
Huge, huge thank you to Leslie for letting me follow her
around her lab and also for putting up
with texts where I was like, hi, I need more maggots.
Can I come film maggots?
It was great.
It was very awesome.
Huge thanks to her and also to all
of you for watching and sharing.
You can click over there to subscribe
if you want to see more videos or also down there to watch
more like this.
Go forth and do science.