Featured Scientist:
Erin S.

Graduate student in Developmental Biology

Name: Erin S.

Birthplace: Woodland, California​

Field of Study: Developmental Biology/ Stem Cell Biology

What organism do you study?: Drosophila melanogaster (fruit flies!)

Favorite thing about science: I love looking at things under the microscope, and discovering how organisms look and work up close!

Fun Facts: I have a puppy named Olaf. I like to grow plants, particularly things you can eat and succulents and I like to go camping, hiking and backpacking!

Follow me on Twitter! @ensanders12

Erin's Science

"How do stem cells in fruit fly guts make decisions?"

When new cells are made in the gut, they then must decide which kind of cell in the gut they need to become. In the gut, a stem cell can decide to become one of two specialized types of cells: a nutrient absorbing cell or a hormone (signal) producing cell. Most stem cells in the gut become a nutrient absorbing cell. Both of these specialized cell types lose their ability to divide and make more cells, but gain the ability to do their specialized jobs. Different signals from the surrounding cells or other parts of the body cause the stem cell to become the nutrient absorbing cell or the hormone producing cell. This process is called “differentiation”, and is what I am really interested in!

At Stanford, I study how special cells make sure that the tissues in your body always have new cells when they are needed. These cells, called stem cells, divide in response to demand from the tissue. For example, if you have an injury and some of your cells die or if you lift weights and your muscle needs to grow, the stem cells will respond and make more of those cells. This process happens all over your human body. However, it is difficult to study how these cells work in a human. So instead, we use the tiny common fruit fly to study how the stem cells in their guts work. 

Female fruit fly (Drosophila melanogaster)

Cell lineage depicting the types of specialized cells a stem cell in the midgut can decide to become. Signals that influence these decisions may come before or after the stem cell divides. 

Fluorescent image of nutrient absorbing (white) and stem cell (pink) nuclei from a small section of the midgut of the fly

To study the midgut, I dissect the gut out of the fly under the microscope using really small tweezers. I use a process called immunostaining to preserve the gut, and label the tissue with colored stains and markers. I then take lots of images of these preserved and stained guts under the microscope! From these images we can count the different cell types, look at where different proteins are located in the cells, and measure different cell characteristics. We have also developed a way to image guts in living flies so that we can study how cells divide, make decisions, move and die!  

These are the forceps I use to dissect the midgut out of the fly!

What questions is Erin asking?

I have a lot of questions that I am trying to answer about how stem cells know how and when to make the decision to become a nutrient absorbing cell! Some of my questions are:

  • How fast do stem cells make decisions?

  • What signals in the gut change how fast a stem cell makes a decision?

  • If you change certain signals in the gut, do stem cells make different decisions?

  • What causes a stem cell to become a nutrient absorbing cell versus a hormone producing cell?

Do you have any questions about stem cells? Fruit flies? Guts? Being a biologist at Stanford? Ask me by clicking below!

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