Rotting meat breeds European Champion

A bacterium that warns you if the meat in your fridge has gone off has won the European Jamboree of the International Genetically Engineered Machine (iGEM) competition for students from the University of Groningen.

The iGEM Competition is a genetic engineering challenge using DNA as a building block. The aim is to engineer a bacterium that can either perform a special trick (such as solving a Sudoku puzzle) or solve a real-life issue. The engineering is with BioBricks, a sort of Lego, but then made from DNA.

On Tuesday, Renske van Raaphorst, Yonathan Dessalegne and Tom van Lente are still a bit dazed as they sit on the ninth floor of the Linnaeusborg Building. It’s just two days since they beat some 50 other teams in Amsterdam. ‘We arrived at the assembly hall at about nine on Sunday morning just as they were announcing the top three teams. And we were one of them! Nothing could ruin our day after that,’ says Tom.

Last weekend they had to present their work of the previous months. The team first got together in March to choose a project, do the research, engineer a bacterium and drink lots and lots of coffee. ‘We worked until literally five minutes before the deadline,’ says Renske. The deadline was six in the morning on 27 September.

They started brainstorming in April. This new team – the University of Groningen has been participating in the iGEM since 2008, when its team and a team from Delft University were the first Dutch bacteria engineers in the competition – came up with a plan, did a literature search and then spent well over a month in the lab.

First, they looked for bacterial genes that were upregulated by the presence of rotting meat. They found a good candidate and removed the ‘switch’ from the bacterium that turns this gene on or off. ‘We made it into a standard building block, a BioBrick,’ explains Renske. They placed the switch onto a circular piece of DNA called a plasmid. A plasmid can easily be transferred to a bacterium, and can also be ‘edited’. Next to the switch, they put a gene that produces a dye. The result: rotting meat flips the switch and the dye production starts.

To get the engineered bacterium near the meat, but not in it (which wouldn’t be too pleasant), the team used small bags of plastic foil. These bags had two compartments, one containing bacterial spores and the other containing a broth that induces bacterial growth. By pinching the foil bag, you break the broth compartment and expose the spores to it, which consequently start growing. The system is thus activated. ‘Fortunately we have three Biomedical Engineering students on our team, who know all there is to know about foils,’ say the three microbiologists.

The theory was sound, but proving it worked in practice turned out to be rather difficult. Just a week before the deadline, they finally spotted some dye in a foil bag suspended over spoiled meat. And equally important: no dye was visible in bags suspended over fresh meat. ‘That was a real eureka moment,’ says Renske. ‘But we couldn’t celebrate just yet. We had to process our results and enter them into the special iGEM Wiki-page.’

During the weekend of the final in Amsterdam, the team first presented their results on a poster and in a short presentation, as did over 50 other teams. They then had to repeat their presentation to the jury on the Sunday of the final. The Universities of Cambridge and Slovenia were the other two in the final. ‘Everyone says “wow, Cambridge” but the Slovenian team is actually much better. They’ve been winning prizes for years now,’ says Yonatan.

But in the end the Groningen team took first prize. Why was this? First, they had a product that really worked, ‘which is unusual,’ and they clearly stuck to the official time limit of four or five months: iGEM is supposed to be a summer project. ‘The Slovenians had done so much it was obvious they had spent at least a year on the project,’ Yonatan explains. ‘We’ve heard rumours that the jury took this into account.’

The Groningen team will now fine-tune their project and presentation in preparation for the World Finals, which start on 2 November in Boston. ‘Our chances? I hope we make it into the top 50 or even 30 percent,’ says Yonatan. ‘There are a lot of very good teams in the finals, but also a lot of teams we’ve already beaten.’

Did you know?

Teams from the University of Groningen have been participating in the iGEM competition since 2008. Last year was the first year with a preliminary round in Europe. The University of Groningen team was the only Dutch team to make it to the finals then. This year teams from the Universities of Delft and Wageningen also made it to the finals, but teams from Amsterdam and Eindhoven didn’t.

The iGEM competition has been held by the MIT in the US since 2003. It began as an internal competition and has since grown to become the international competition that it now is. It is only since 2006 that winners have been chosen.

Read more about the University of Groningen team on their iGEM webpage, where you can also find more information on the competition.