2014 is the 10^th Anniversary of iGEM Competition. To celebrate the 10^th Anniversary, from October 31^st to November 3^rd, we had a Giant Jamboree at Hynes Convention Center, Boston, MA. Unlike previous year’s competition’s two-tiered structure, in 2014, there are no more Regional Jamborees; everyone can come to Boston to enjoy the gathering and share their ideas and accomplishments with iGEMers from all over the world.

This year, HUST_China focused on treating sewage containing copper ion, cyanide and fluoride, the main common pollutants in industrial waste water. To reach the goal, we designed and constructed E. kungfu, which is capable of absorbing copper ion, degrading cyanide and detoxifying fluoride. Why do we call our engineered bacteria E. kunfu? Because they are so potent in defeating bad guys (pollutants) and recovering valuable resources (copper ion), which well represents the characteristics of Chinese kungfu.

E. kungfu is actually consisted of two strains of biologically engineered E. coli, one is E. worker (Figure 1) and the other is E. instructor (Figure 2).

Figure 1. E. worker

E. worker functions as a worker that treats sewage containing copper ion, cyanide and fluoride; it is consisted of a work system and a kill switch.

The work system carries genes encoding a copper binding protein, a fluorinase (flA) and an operon that is capable of degrading cyanide (RTS). The copper binding protein is displayed on the cell surface (see surface display system); it is composed of a copper binding peptide and an anchor protein of the cell membrane/wall. According to our experimental results, both OmpC and OprF function well as the anchor protein, and both CBP and 6×His tag are good choices of copper binding peptide. All the functional parts in the work system are under the regulation of an induced promoter- PpcoA, which is sensitive to the concentration of copper ion; the work system is active only in condition of high copper ion concentration.

The kill switch is added to our E. worker out of the concern for biosafety. Our    E. worker can express toxin protein and kill itself when exposed to high intensity of UV, thus the application range of the bacteria is fully under the control of the user. The working mechanism of the kill switch is a little complex; please click here to view the detail.

Figure 2. E. instructor

E. instructor works as a reporter of the whole system, telling the user whether the sewage is treated completely; it is consisted of a work system and an instructor system.

The work system in E. instructor is exactly the same as the one in E. worker; but it is not designed for treating sewage, instead it is used to ensure that our bacteria can survive in high concentration of pollutants.

The instructor system expresses RFP when the copper ion concentration is high, while expresses GFP when the copper ion concentration is low. Users can decide whether the sewage is treated completely according to the color of the fluorescent protein. Click here to know the detailed working mechanism of our instructor system.

Here is 2014 iGEM project poster (Figure 3) by team HUST_China. Click the picture, then you can view details.

Figure 3. 2014_iGEM Poster

iGEM, a premiere undergraduate Synthetic Biology competition, is one of the most important events in my college life; it is hosted by MIT (Massachusetts Institute of Technology) every year since 2005. Click here to know more about the competition.

In the competition, we organize a team (undergraduate students only) to design a project based on synthetic biology and realize the idea by ourselves. Most experiments are done through the summer vacation, but other things necessary to the competition, such as human practice, website designing, poster designing, will altogether take us about a year.

As a competition, its duration is really long and very time-consuming; we experienced many difficulties and failures and many teammates quit. I’m glad I didn’t give up and the team finally conquered all the obstacles. I represented the team to give the final presentation in November, 2013, MIT.

In 2013, our team made a biological oscillator, which can release propionate (recently reported to be able to relieve hypertension) periodically to cope with the morning surge of patients with hypertension.

Here is the design of the biological oscillator.

Biological Oscillator

Hybrid promoter is the combination of the activation operator site from araBAD promoter and the repression operator site from lacZYA promoter. It can be activated by the AraC protein in the presence of arabinose and repressed by the LacI protein in the absence of IPTG. The mechanism of the oscillator is that we can activate the promoter by adding Arabinose and IPTG to the medium and thus results in the transcription of each component of the circuit. The increased production of AraC in the presence of Arabinose results in a positive feedback loop that increases promoter activity. However, the concurrent increase in production of LacI results in a linked negative feedback loop that decreases promoter activity. The two feedback loops with opposite effects can then drive an oscillatory behavior. Click here to know more about our project!

We designed and made a poster (Figure 1) for our  porject. Click the picture, then you can view details in our poster.

Figure 1. 2013_iGEM Poster

This experience is unforgettable! I really enjoyed working in a team, and most importantly, I learned how to solve problems when getting stuck in a research and how to express myself properly and effectively in a team.

Team HUST-China 2013

I met many friends during the Jamboree, MIT. This is Alex from the University of Marburg.