Bacterial defiance as a form of prodrug failure

Brandon Alexander Holt; Gabriel A. Kwong

To demonstrate the use of multiple prodrug transistors in biological circuits capable of killing defiant bacteria, we selected three variables (i.e., bacterial nutrients, temperature, linker 15 substrate kcat) that independently influence bacteria-prodrug competition to act as circuit inputs (i.e., A, B, and C respectively). For each circuit input, we assigned the value 0 or 1 by fixing all other variables and choosing one condition that enabled bacterial survival (i.e., IN = 1 when BAH > BAHcrit) and one condition that resulted in bacterial death (i.e., IN = 0 when BAH < BAHcrit). We then designed a biological circuit to kill bacteria (i.e., OUT = 0) under all eight combinations of 20 nutrient (LB Broth = 0% or 2%), temperature (T = 30 o C or 37 o C), and linker substrate (kcat = 7 x 10 7 s -1 or 2 x 10 6 s -1 ) conditions while using three AND gates and one NOT gate (Fig 4A) .