Profile

I am originally from Greece, born and raised in the city of Pireas which is adjacent to the capital and is the historic port of the region since ancient times. I have not been back since last January, but I try to visit my mum and Lou the cat every few months for a long weekend and during the holidays. The good thing about going back home for the holidays, apart from seeing family of course, is that even though it is cold (often chillier and snowier than here) there is always the sun. I fondly remember spending a lot of time outside in the sun last Christmas.

I moved to England around 7 years ago now and spent the first 5 years living in London before I started my PhD in Bristol. Here, I live in a top floor flat in Clifton with a fantastic view of the city which is certainly worth the extra rent I am paying for it. I live by myself which is quite nice because I can indulge myself in my hobbies when I am free and don’t have to worry about other people’s dirty dishes.

Speaking of favourite pastimes, I like to listen to a lot of music. I enjoy a variety of different genres and instruments. Lately it has been smaller, independent, bands who often play folk, jazz, and blues or anything along those lines. I used to go to a lot of live music events before covid19 and I dearly miss it so many of these smaller recorder conferences are a wonderful way for me to relive that experience. I have discovered so many great bands I will go and see live when I can, I recommend the tiny desk youtube series for anyone interested!

I also spend a lot of my time cooking nice food by myself or with my quarantine buddy. We try to go outside and use our barbecue and smoker when the weather is nice. It is a great experience and looking at a fire for 10 hours really helps my mind recharge from all the science things I look at for the rest of the week.

I have also joined the lockdown baking bread trend and I will show you one of my finest creations, this salt and rosemary focaccia!

My pronouns are he/him.

My aim at work is to understand how cells communicate and decide which cells take over our tissues (organised groups of cells) and organs. The cells that take over are called winners and the cells that are eliminated are called losers. This process is called cell competition, and it is essential in keeping us fit and healthy. Below is an awesome drawing my friend and colleague Kelli made to accompany our lab group’s more boring diagram of cell competition.

Of course, we have many different organs, and this process will be different in every one of them. So, I use a model to study cell competition where one experiment will not differ too much to another. The model organism I use is the fruit fly, and the fruit fly organ I have chosen is the wing disc. These wing discs are effectively the larva (maggot) equivalent of wing of adult flies. Keep in mind, flies start life as eggs, then become larvae, then become pupae, and finally transform into adult flies. And this all happens in a few days!

One of the reasons I use the wing disc is because it has two parts, the anterior (front) and posterior (back) which grow independently of one another. This means I can perform experiments in the anterior (i.e. make all the cells losers) and keep the posterior as winners. In the example shown, I have made the loser cells cyan while the winners only have the background sky blue colour which labels the whole wing disc. Knowing which cells are winners and which cells are losers allows me to visualise, measure, and track changes in another colour, in this case orange. This image therefore tells us that the loser cells (cyan) have a lot more orange intensity than the winner cells (sky blue background colour only). We can label any molecule of interest this way and track the changes between winners and losers.

I can also create conditions where I have patches of cells where they are directly competing. Remember, the anterior and posterior compartments grow independently and in fact there is no competition between them! This allows me to tamper with the cells and see if the winners are not as good at eliminating the losers. This is shown in the following image with loser cells being green and winner cells being unlabelled. So, the percentage of green in the disc (i.e. 20% of the wing disc is green) would dictate how many loser cells are remaining in the wing disc.

I acquire my data using an imaging technique called “confocal microscopy”. A confocal microscope allows me to zoom into a very thin section of my sample and produce the images I have shown above. Having a very thin section visualised is great because that eliminates interference structures above and below with what I am seeing. I can also acquire multiple “slices”, i.e. images above and below the original field of view and stitch them together to create a three-dimensional stack of images. I used this example last year in FUTURES 2019 to show how acquiring a stack looks and how depth information can be important in understanding biology.

The confocal microscope is also fitted with multiple different lasers which allow me to detect the labelled cells I have described above. Shining a particular laser through my sample will highlight a label of a certain colour (i.e. one laser for green colour, one laser for orange signal etc.). Altogether, this technology allows me to create labelled, high-resolution images of my wing discs. And they are also very pretty like this video! (If it doesn’t load just click on it should lead you to the video)

View post on imgur.com

This leads on to the topic of how do make cells losers. And how can I tamper with cell competition as I said above. Remember, one of the great things about flies is that they only take a few days to grow from eggs to adults. This is rapid compared to many other models we use in biology, that can take months. Even better, the fruit fly community has developed a huge collection of genetic tools that can be very easily be used in our experiments. These tools let me label loser cells with a colour or make them have more or less of a specific protein and then see what the effect is on cell competition, and much more. Indeed, fruit fly and DNA manipulations are almost synonymous as this picture shows!

But how do genetic tools work? Basically, they are regions of DNA that are linked with a specific physical trait. This trait can be our flies having green loser cells or me having brown eyes and hair. These regions of DNA are called genes and they occur naturally in the case of my eyes and hair but can also be edited to express the information we want, in the case of green fly loser cells. These traits are directly inheritable from parents to children and we can track them across generations to make sure our flies express the right traits so we can do our best experiments! I want to finish off this section with a drawing I took from Khan academy about genetic inheritance and a recommendation for anyone interested to go check them out. They are a non-profit educational organisation you can get lost in!

https://www.khanacademy.org/

So how does my day in the lab look? Well, a lab that works with flies needs a dedicated room to keep the flies and do all our fly work in, the fly room!

In there we store all our flies in tubes and trays, as you can see. I have many different trays with different purposes, from maintaining fly stocks to selecting the kind of flies I want for an experiment and running the experiment in a separate tray as well.

The reason I do this, apart from organising everything so I can find it, is because flies lifespan varies a lot with temperature. This means I can maintain my stocks at a lower temperature, 20 ^oC, where I won’t need to tend to them as much because they will live longer. At the same time, I can choose to run my experiments at any temperature I want, usually 25 ^oC. There is a lot we can change in fly biology by changing the temperature so if you are interested to find out more then please ask me!

To start a new experiment, I select males and females with the genes we want (e.g. larvae will be losers and green like above) and then place them together in a new tube.

Note: some flies have a mutation that makes them have curly wings! That helps me select the ones I want.

A week after that I will have the larvae I want and will dissect out the wing discs and prepare them for imaging. Essentially, I attach chemicals to the wing disc that will label my targets of interest in different colours. I can explain in more detail for anyone curious, please ask me.

I haven’t added any pictures of larvae in case some people are not keen on seeing maggots, but let me know if you want to see any.

When the wing discs are ready to be imaged, I will head down to the basement where the microscope is. This is the last step in our protocols and often how I finish my days, although I can image at any time I want theoretically. I usually sit down here and watch youtube videos or answer emails while imaging my wing discs

The best and worst thing about this room is that is it is always dark and a bit chilly for the microscope to work optimally. Therefore, when I emerge after multiple hours of imaging I am always greeted with the warmth of the radiators or a warm summer’s day. Although nowadays I go in the afternoon and come out when it’s dark outside which is quite confusing.