Tonight was the last EUSci seminar of the year, and we certainly had an interesting enough set of talks to see us through the empty summer months. The speakers and audience seem to consist mainly of biologists, which should be an incentive for me to persuade some mathematicians to take the floor and give a talk in future!
The first talk was about the Human Epigenome Project, by Sam Corless. He started off by asking the question “if every cell in our body contains the same DNA, they why don’t we look like amorphous blobs?”. The answer is epigenetics. Sam describes this as being like a set of post-it notes on every cell of your body, describing which genes from the DNA it wants to use or inhibit. So there are epigenetic markers in your eyeballs to tell the cells to activate the eyeball genes and inhibit the bone-making genes, for example.
There are some diseases which are genetic (e.g. baldness); these result from mutations in your genes, and are not curable using drugs. You’d have to replace your whole DNA with a non-mutant, normal version of the gene to fix the problem. However, some diseases (e.g. diabetes and some types of cancer) have been shown to be epigenetic: it’s the markers on the cells which are the problem, not the DNA itself. These diseases can very often be cured with drugs, which is why scientists are so interested in trying to understand these markers better. The Human Epigenome Project has the goal of mapping out 1000 genomes in the next 7-10 years, which is going to be a very tough job but we are already seeing the benefits in new medicines that are coming out of it.
The second talk was called ‘An Evening of Excitation’ by Catie Lichten, and is a talk that Catie will be giving at the National Museum of Scotland in a few weeks’ time. I’m sure it’ll go down great – it was certainly a hit with the postgrads! Catie explained to us the principle behind fluorescence: some objects can absorb energy from a light source (e.g. the sun, or a lamp) and then emit it again later. The colour of light tells you how much energy it has, with blue light being the most energetic and red light the least. Under a UV lamp (which is very energetic!) some examples of objects which fluoresce are bananas (especially if they are a bit bruised!), tonic water (it goes a nice blue colour) and, of course, fluorite rock (where the word fluorescence comes from!).
There are other ways that objects can emit light other than fluorescence.
- Chemoluminescence: object emits light as a result of a chemical reaction. E.g. when you crack a glow stick.
- Bioluminescence: same as the chemi-one but happening inside a living organism. E.g. there is a shrimp whose vomit is bioluminscent in order to scare away predators.
- Triboluminescence: glowing that comes from breaking a material apart. E.g. Catie recommends breaking a polo mint apart with a pair of pliers in a dark room.
So, where is the research in all of this? Well, there are jellyfish which are fluorescent, and it was discovered that their cells contain something called green fluorescent protein or GFP for short. The discovery and isolation of this protein turned out to be so incredibly useful in biology that the guys who found it won a Nobel Prize in 2008! Scientists inject this protein into living cells so that they glow and can be tracked and analysed in real-time.
One animal they’ve been injecting it into is the zebrafish, which brings me nicely onto the third talk of the evening, by Carl Tucker. His job was to explain to us why it is that zebrafish are being so useful in medical research. Believe it or not, these little 4cm-long fish are being used to investigate diseases such as congenital heart defects, deafness, multiple sclerosis and muscular dystrophy.
The main reason that zebrafish are so useful is that the embryos are completely transparent, allowing scientists to see the development of all the internal organs. At the harder-to-reach places they can inject GFP to be able to watch things like blood vessels forming. A day-old fish heart is remarkably similar to a 23-day old human heart in terms of the way the tissues are forming (apparently). Of course, adult zebrafish are fun to study too, but the majority of them aren’t see-through. (However, a transparent zebrafish has now been bred – it is called Casper for obvious reasons!) We can use ultrasound to ‘see’ inside the fish, and they don’t even need anaesthetic because they fall immediately asleep when turned upside down!
Probably the most amazing thing about zebrafish is their ability to regenerate bits of themselves. Being a bit evil, some scientists decided to shoot a hole in the heart of a fish using a laser; within 24 hours the fish was completely back to normal. The spine regenerates fully within a month. With a good microscope, you can simply watch the white blood cells ‘bimbling around’ (in the words of Carl) and heading off to heal wounds. If we can figure out what exactly is going on inside these fish then there’s a clear hope of being able to heal similar wounds or defects in human hearts and spines.
So, another set of inspiring biological/medical talks that give us lots of hope for curing a range of diseases in the future. Keep up the good work guys (but go easy on the poor fishies…)!