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From 2010.igem.org

Week-2 (Investigation of Singing E.coli project)

We think the singing E.coli project will be an innovative, valuable and interesting topic for 2010 iGEM competition. Its concept could be applied to some environmental project, such as removal and detection of specific heavy metals. However, concept only is not good enough for practical work and we decided to have more digging on the scientific background for it.

The first thing come up in our minds is to express molecular magnetic protein in the E.coli. After searching some online sources, we found some natural protein have magnetic properties, such as Magnetoferritin. Ferritin is a spherical polypeptide cage capturing a nano-sized core of ferromagnetic iron oxide magenetite. It could be synthesized by in vitro accoding to F. Meldrum team in 1992. i However, their synthesis method is based on horse spleen ferritin under controlled reconstitution condition. It would be quite tricky to synthesize the animal protein in bacterial cells. Another magnetic protein, metallothionein, which is an antioxidant in mammalian, was excluded from the consideration for the same reason.

The second idea is to insert metal-ion attractive group from magnetotactic bacteria into the fusion protein in E.coli. But the genes of magnetic group are not well defined which might cause quite a big problem during cloning.

The third idea is to insert the chemotactic (thermotactic) protein in magentotactic bacteria. However, culturing of those bacteria might be a problem. Our group searched culturing methods for 12 species of most common magentotactic bacteria. We checked DSMZ which sells some magnetotactic species ii and found that kind of organisms are quite difficult to cultivate, complex medium, anaerobic or micro-aerophilic. Moreover, as limited research is done on magetotactic bacteria, the available genetic systems might get problem when introducing new genes in these bacteria.

So we finally decided to give up this interesting but a bit intangible idea and working on the living biological clock project.