Finally, E. coli is good for something other than making you regret not washing that lettuce better. Boffins at the Imperial College London have employed the bacteria as living Boolean logic gates—potential building blocks for bio-computers of the future.
The research team, led by Baojun Wang, created the AND gate within a bacterial host using a pair of "promotor" inputs. When both inputs are present they create a pair of co-activating genes which, drive the production of two specific proteins that interact with one another to instigate a third gene which drives the output.
So basically, if two predetermined environmental inputs are present, they activate a pair of genes in the E coli which produce proteins that in turn cause a third gene to create the desired output. It's essentially a custom-designed genetic logic circuit. Surprisingly, this process isn't that far off from natural gene expression—wherein specific inputs cause specific genes to turn on for specific intervals and generate proteins that become the inputs for other genes further down the line.
The team has also developed a NOT gate using the same techniques and combined the two bacteria to create a genetic NAND gate. As the team's findings explain, "we can program living cells to generate precise desired behaviours in response to specific extra or intra-cellular signalling inputs." If enough of these genetic gates can be spliced together—and that's still a long ways off—living "digital" computers could one day be developed.