ABSTRACT :
Synthetic Biology (SynBio) seeks to reprogram systems that are already found in nature to
produce computer-like behaviours, that is to render more programmable, robust, and tightly
controlled biological systems. SynBio circuits can be built into a single cell or distributed in a
population. In the first case, the complexity of the circuits is impaired by the burden imposed on
the cell. Genetic circuits distributed in a community generally rely on chemical messengers to
connect them, but they exhibit low specificity, leading to circuit crosstalk. Inspired by other cell cell communication strategies, we propose the use of plasmids to wire the computing populations
via conjugation. Indeed, our research group succeeded in implementing AND and OR logic gates
distributed in three bacterial populations, as well as in plugging them into combinational circuits.
In this work, we have advanced in complexity and designed the architecture of a plasmid-based
Programmable Logic Array (PLA), a device able to calculate any Boolean function. To this end,
we designed and built NOT logic gates based on fertility inhibition, as well as YES logic gates
based on conditional replication. In the construction step, different plasmid backbones, fertility
inhibition genes, and replicons were evaluated. The performance of the NOT logic gates was
tested by conjugation assays, and optimal conditions were set up, achieving distinguishable “1”
or “0” outputs. The YES logic gates were assessed by growth curves. These devices have potential
applications in several fields, such as biocomputing, biomanufacturing, or theragnosis.
