E.HOP: A Bacterial Computer to Solve the Pancake Problem W. Lance Harden2, Sabriya Rosemond3, Samantha Simpson1, Erin Zwack1 Mentors: A. Malcolm Campbell1, Karmella Haynes1, and Laurie J. Heyer2

1
E.HOP A Bacterial Computer to Solve the Pancake
Problem W. Lance Harden2, Sabriya Rosemond3,
Samantha Simpson1, Erin Zwack1 Mentors A.
Malcolm Campbell1, Karmella Haynes1, and Laurie
J. Heyer2
1Biology and 2Mathematics Departments, Davidson
College, Davidson, North Carolina 3Biology
Department, Hampton University, Hampton, VA
1. The Burnt Pancake Problem
4. Two Pancake Constructs
(1,2)
(-2,-1)
(1,-2)
(2,-1)
Problem Solved
Unsorted Pancakes
(-1,2)
(-2,1)
Can E. coli be programmed to compute solutions?
(-1,-2)
(2,1)
2. Mathematical Modeling
5. Results
Solution is (1, 2) or (-2, -1)

• ( 1, 2)
• (-2, -1)

( 1, -2) (-1, 2) (-2, 1) ( 2, -1)
Amp, Kan, Tet AraC/ Hin Tet Resistance Hin Vector IPTG Hin Induction Amp Tet Tet Resistance
(1, 2)? Hin-LVA (1, 2)
(1,-2) (-1,-2) ? AraC/Hin-LVA (1,-2) (-1,-2) ?
8 different stacks of two pancakes Assume all
possible flips are equally likely Need to build
one construct from each family
(-1, -2) ( 2, 1)
Screen forOrientation
Repress pBad-Tet
Activate pLac-Hin
3. Biological Pancakes
6. Conclusions
PRACTICAL Proof-of-concept for bacterial
computers Data storage n units gives 2n(n!)
combinations BASIC BIOLOGY
RESEARCH Improved transgenes in
vivo Evolutionary insights
Plasmid 1 Two pancakes (Amp vector)
Tet
RBS
hixC
hixC
hixC
pBad
Plasmid 2 AraC/Hin generator (Kan vector)
AraC PC
Hin LVA
RBS
pSB1K3
pLac
Thanks to Missouri Western State University,
HHMI, Davidson College, James G. Martin Genomics
Program, and MIT