David Christensen

My week is nearly over :( I might still come on now and again to have a look at your questions though!



University of Southampton 2006-2010, University of Oxford 2010-2014


Biochemistry degree (MBiochem)

Work History:

Washed dishes during university holidays at Athelhampton House restaurant in Dorset 2007-2010!

Current Job:

Final year PhD Student


University of Southampton

Me and my work

I’m looking at how stem cells control how much sugar they eat.

I work with human embryonic stem cells, but unlike a lot of scientists who might want to find ways to produce hearts, livers, kidneys or brains from their stem cells, I’m trying to find out how we can make a stem cell stay as a stem cell. A lot of the time stem cells decide (without us telling them what to do) to become a different cell type, such as a muscle cell or a heart cell. Sometimes different stem cells that are next to each other might become different types of cells. This can be a problem if you have stem cells that you want to make into a liver, but some of them are already becoming heart and kidney, because a mix of different types of cells would be useless for treating your patient with liver disease. Because of this, some scientists, including me, are trying to find what makes stem cells happy to stay as stem cells.

One thing we know about stem cells is that they consume a lot of glucose sugar. When the stem cells become other types of cells they start to consume a lot less sugar. We are trying to find out how this is controlled and how we can affect how much sugar the stem cells consume. One thing that we know affects how much sugar the stem cells need is how much oxygen is available to the stem cells. All cells in our bodies need oxygen to live and get oxygen from the blood, but some cells need and get more oxygen than others. It seems that stem cells need less oxygen than other cells and giving them more oxygen than they need changes the way they behave and makes them less happy to stay as stem cells. At the same time, giving them more oxygen than they need makes stem cells consume less sugar. I’m interested in how and why having more oxygen makes stem cells consume less sugar and makes them less happy to be stem cells.

My Typical Day

The stem cells I use need to be carefully looked after every day so I spend a lot of time looking at them.

One great thing about my work in a lab is that I can start work whenever I want in the morning! Generally I start work at 9 and go home at 5, but some days I get in later and some days I leave early – on the best days I get to work late and leave early!

To keep the stem cells happy, I need to feed them every day and move them onto new plates every few days so that they don’t grow on top of each other. This means that I have to look at them every day to see whether I think they just need to be fed or whether there are too many of them on that plate and I need to take some of them to go onto a new plate where they will have more space. Because the stem cells are so needy I have to go into the lab to do some work on weekends quite often, which is really annoying!

Although feeding the stem cells is something I do every day, it isn’t actually the work I do to try to learn new things about the stem cells. To learn more about the how stem cells consume sugar and how they are affected by the amount of oxygen available, I have to do various experiments to compare stem cells that I have grown separately and differently. For example, I always have stem cells that are being grown with a lot of oxygen and also stem cells that have very little oxygen. These stem cells are grown in a liquid with sugar and other nutrients in it that the stem cells need to grow. If I know how much glucose sugar there is in this liquid before I put the stem cells into it and then I can measure how much sugar is left in it a bit later, then I can work out how much sugar the stem cells have eaten from that liquid. As I do this experiment with stem cells that are grown in lots of oxygen and stem cells that are grown with very little oxygen, I can see whether the cells grown in less oxygen eat more or less sugar. Recently I found out that stem cells grown in less oxygen do eat more glucose sugar.

My Interview

How would you describe yourself in 3 words?

Tall. Enthusiastic. Sentimental.

What living thing amazes you the most?

Probably people! Other animals are cool too, but look at all the amazing things we can do!

What is the most fun thing you've done?

Zorbing – the thing where you roll down a hill in a big ball with some water inside it too.

Were you ever in trouble in at school?

Sometimes, but not too much.

If you weren't a scientist, what would you be?

In my dreams I’d be in a band or at least write about music for a magazine, but probably I’d be even more boring than I am and be working in a bank or something!

What's the best thing you've done as a scientist?

It’s really exciting when you see that work you have done has been published in a journal that will be read by other scientists all over the world and so far I’ve had that twice.

Who or what inspired you to become a scientist?

I don’t remember any individual person or thing that happened to inspire me. I think it just happened without me noticing! I always enjoyed watching the Christmas Lectures as a kid though.

What would your superpower be?

Reading peoples minds.

If I could change one thing about the world...

I’d just make everybody a bit nicer.

My favourite CHRISTMAS LECTURE memory is:

I don’t remember any particular lecture series from when I was a kid, but I’ve watched them every Christmas since I was a kid, so it’s part of my Christmas routine now. They always felt like such a cool thing to see in the few days sat around at home after Christmas.

The most Fantastic thing about Life is:

Just that we have it! There’s so much awesome stuff out in the world. Some of it’s natural and some is man-made, but we’re a product of evolution and nature, so it’s all part of life and it’s all fantastic!

Other stuff

Show us where you work:

This is a tissue culture hood where I feed my cells in a sterile environment to stop myself from getting infections in my cells.


This is the lab where I look after my cells. At the end of the room on the left are the incubators where I grow the cells to make sure they are kept at a warm enough temperature for them to grow well. We can also control how much oxygen the cells get to see how different amounts of oxygen affect the cells.


Here’s a microscope with a plate of my cells. I have to look at my cells every day to see that they still look happy.


We have lab meetings once a week where we take it in turns to bring in cakes, biscuits or sweets that we’ve made. I made these!: