ETH 2006 Half adder
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Half-adder or Full-adder
An implementation of a half-adder or full-adder: 1-bit adder with carry
- [http://en.wikipedia.org/wiki/Full_adder half/full adder in wikipedia]
Idea: Pattern recognition
→ Illustration of the concepts:
Main Goal:
- Write something with a chemical on a petri plate (like ETH for example)
- Let Bacteria grow uniformly on the plate
- Expose the plate to a picture (black and white) of the same pattern
- Result:
- Bacteria gets green when pattern on the plate and picture match (light and chemical)
- Bacteria does not express fluorescent protein when pattern on the plate and picture match (no light and no chemical)
- Bacteria gets red when pattern on the plate and picture do not match
Implementation
Implementation from the ingenieur point of view
- Half Adder
- = opportunity to build an AND and an XOR Gate
Implementation from the biologist point of view
- AND Gate: presence of chemical induces the production of an inactive protein, which is activated by a second protein (produced when light is present): the first protein is then activating GFP production
- XOR Gate: I think Marko had a good idea about that (I didn't really got it)
- a light sensible promoter (there are some, see [http://partsregistry.org/Featured_Parts:Light_Sensor here])
- a chemical sensible promoter (chemical to be defined)
- we would need to give a kind of first signal to the system (to don't have light reactions before a certain moment, otherwise we have to work in a dark room...), an activation signal after the bacterias have grown on the plate
Chemical Sensing
- Lactate lacI represses, IPTG induces ([http://partsregistry.org/Part:BBa_R0011 BBa_R0011] or [http://partsregistry.org/Part:BBa_R0010 BBa_R0010] )
- Tetracycline, TetR inhibitor, Tet inducer by inhibiting TetR (or aTc, it's analog) ([http://partsregistry.org/Part:BBa_R0040 BBa_R0040])
- combination thereof ([http://partsregistry.org/Part:BBa_I13614 BBa_I13614] / [http://partsregistry.org/Part:BBa_I13617 BBa_13617] / [http://partsregistry.org/Part:BBa_I13623 BBa_I13623] / [http://partsregistry.org/Part:BBa_I13624 BBa_I13624] / [http://partsregistry.org/Part:BBa_I13627 BBa_I13627] /
[http://partsregistry.org/Part:BBa_I13637 BBa_I13637] / [http://partsregistry.org/Part:BBa_I13653 BBa_I13653])
- simple sugar Arabinose ([http://partsregistry.org/Part:BBa_R0080 BBa_R0080])
- I see the main difficulty in the spatial separation as the cells are growing in the petri dishes. since the inducers are water-soluble we would have to fix the chemicals onto the petro dish.
Modelling
Selected XOR/AND Model Variants
- eth-parts-and-xor.pdf (∼0.5M) file versions
- eth-parts-and-xor.ppt (∼0.6M) file versions
Old
- eth-xor.pdf (483KB)
- eth-and.pdf (185KB)
- AND34.ppt
Parts
We have already reserved parts for the adder and the gates in the registry the description of which are still tentative:
- Half adder: [http://partsregistry.org/Part:BBa_J34000 BBa_J34000]
- AND gate: [http://partsregistry.org/Part:BBa_J34100 BBa_J34100]
- XOR gate: [http://partsregistry.org/Part:BBa_J34200 BBa_J34200]
Pro's & Con's
Pro's:
- meaningful from engineering point
- valuable parts for synthetic biology
- stepwise proceeding applicable (→ intermediate and partial results!)
- experiments visually attractive
- probably simple enough
Con's:
- cheap copy of “bio-film” project ([http://partsregistry.org/cgi/htdocs/SBC04/index.cgi iGEM 2004])
- sensational experiments, have little in common with half adder
- maybe that a big vision is lacking
- general/practical benefit? (counter-argument: is this required?)
- too simple?