Dr Charbin’s Science & Medical Blog – Hot and current topics in the world of science

Here we will discuss hot and current topics in the world of science, where important new discoveries and  research flashpoints will be shared and discussed. Oxbridge interviewers often ask about current scientific affairs, so it is very important to be aware of new developments and have informed opinions on them! This blog is written by Dr Adrian Charbin, who studied Natural Sciences at Sidney Sussex, Cambridge. Having specialised in genetics in his final year, Adrian went on to complete a PhD in Biochemistry and Molecular Biology while working for Cancer Research UK and University College London.

Animal Biology

To kick things off, I thought I would start by sharing one of my favourite science stories to emerge over the Christmas holidays: the discovery of a spider species that creates a decoy to escape predation in the Amazon rainforest.

From afar, it appears to be a medium sized spider about an inch across, possibly dead and dried out, hanging in the centre of a spider web along the side of the trail – nothing too out of the ordinary for the Amazon. As you approach, the spider starts to wobble quickly forward and back, letting you know this spider is, in fact, alive. Step in even closer and things start to get even stranger. That spider form you were looking at is actually made up of tiny bits of leaf, debris, and dead insects. The confusion sets in; how can something be constructed to look like a spider, how is it moving, and what kind of creature made this?

It turns out the master designer behind this somewhat creepy form is in fact a tiny spider, only about 5mm in body length, that is hiding behind or above that false, bigger spider made up of debris. It is most likely a new species from the genus Cyclosa, a genus known for having spiders that put debris in their webs to either attract prey, or in this case, confuse anything trying to eat them. Indeed, studies have found that some Cyclosa species have a higher survival rate against potential predators like paper wasps because the wasps end up attacking the debris in the web rather than the spider itself. Watch the rather enthusiastic leader of the expedition that discovered these spiders describe the find here.

Psychology

The next story comes from the world of psychology where a new research report by Dr Darby Proctor suggests that humans and chimpanzees share similar preferences in dividing rewards, suggesting an evolutionary history to the human sense of fairness. In this study, chimps and preschool children performed in a cooperation task known as the ultimatum game. In the game’s standard version, one player splits a pot of money with another player. If the receiver accepts the proposer’s offer, both players keep their shares. If the receiver rejects the offer, both players get nothing. A video describing the task used can be seen here.

A common Oxbridge interview question is to design or evaluate an experimental design. Having watched the video above showing the experimental protocol for the ultimatum game, do you have any suggestions or criticisms? Think about what factors make for a good experiment and try and come up with a few possible problems with the proposed experimental design. Once you have some ideas, read this article, which discusses some of the possible flaws of this new research report, and see if your ideas match!

Cell Biology and Medicine 

Last week saw the unveiling of a new report on the possibility that DNA can be found with a ‘quadruple helix’ structure inside human cells. Normally, the tertiary structure of DNA is the famous double helix as discovered by Francis and Crick in 1953. However, it has also been proposed that a quadruple helix structure could also be chemically stable, but no evidence was found that such structures could actually be found inside most living organisms (except for ciliates, where these structures have been detected).

This new report was able to identify for the first time the existence of DNA quadruplex structures in human cells by labelling the cells with antibodies that could specifically bind to these unique structures. What was even more intriguing was the fact that these quadruplex structures appear transiently during S-phase of the cell cycle, when cells are busy replicating their entire DNA in preparation for cell division (mitosis).  From a medical perspective, this discovery raises the intriguing possibility of a new angle of attack for chemotherapy targets in cancerous cells. As cancerous cells are constantly undergoing cell division, they will often be going through S-phase and therefore creating these transient quadruplex structures.

Current chemotherapy treatments can be very hazardous to patients undergoing treatment and there are many possible side effects. The most common and characteristic effects of chemotherapy include complete hair loss as well as vomiting and diarrhoea.  What do you think your hair follicle cells, the epithelial lining of your digestive tract and cancerous cells all have in common? This question was one actually put forward to me during my Cambridge interview and I’ll share the answer in next month’s instalment of this blog.

I look forward to seeing you next month!