The Bacterial Computer
This week my students will be trying out the “bacterial computer.” Originally constructed by biology students for the GCAT consortium, the bacterial computer has a plasmid of three flippable segments, two of which encode fluorescent proteins (red and green). The DNA segments get flipped by a protein called Hin Recombinase, originally invented by Salmonella enterica to flip its genes for expressing different coat proteins that fool the human immune system. In the plates above, the upper plate has both plasmids flipped off; the lower left, both green and red on (makes yellow); and the right, only red. But continued flipping can generat plasmids that fluoresce red with a bit of green, or vice versa, and other unexplained things. Biology is always a bit more complicated.
The plasmid can solve a Hamiltonian problem by ending up fluorescing yellow. This may not sound like much, but it reminds me of the plastic computer I built in the 60s that could only count to seven. Who knows what kind of computer our children will have on their desks–or whether they’ll have desks at all.