Idea 6/11
From 2006.igem.org
Contents |
Calcite/Calcium Phosphate Project (Idea 6/11)
Aim
To create a 3D structure in a defined area using bacteria which can precipitate out a calcium compound.
Background
Possible Methods
Initial colony makes phosphatase or urease in response to stimulus from UV, or absence of UV signal. The enzyme catalyses the conversion of calcium and phosphate/carbonate ions in the medium into calcium phosphate or calcium carbonate. An amplifier can be incorporated if the resulting amounts of 'hard' material need to be increased.
Possible Problems
How will the Calcium compound be restricted to only the areas activated? It could diffuse around the area and lose the original pattern.
How to activate the phosphatase or urease AND switch it off.
Possible that phosphatase and urease don't cause calcium compound to precipitate in sufficient quantities.
Parts Required
phosphatase or urease
More!
Experiments Required
Experiments for Idea 2.
Is calcium phosphate or calcite better at precipitating?
Urease vs. phosphatase.
- Proteus vulgaris produces urease and colonies of P. vulgaris lower the pH by producing ammonia. A test can be done with Proteus vulgaris to see if this causes calcium to precipitate from the medium with some different concentrations of calcium ions. Locate an E. coli phosphatase and do a similar experiment, to see which compound is the 'best' solid material.
- Locate urease/phosphatase in E. coli that is suitable. Find optimum CaCl2 concentrations, phosphate donor concentrations in medium. (Just test with genes coupled with constitutive promoters?) Can also see what happens when the medium, and if the medium becomes depleted of calcium or phosphate ions. End - Find a suitable ratio of calcium to phosphate ions in medium.
- Urease increases pH, measure pH change caused by different densities of bacteria, find if the pH change produced by E. coli in a lawn is suitable (high enough) for causing calcite to precipitate.
