Researchers at the Massachusetts Institute of Technology (MIT) have developed a biological circuit using live bacteria. This circuit can process information. It could help plants detect and respond to environmental threats. The work was published in a recent study.
Living Biological Circuits
The MIT team created a system that mimics electronic circuits using bacteria. Instead of electricity, these bacteria use small molecules to send signals. This allows the bacteria to act like biological switches and relays.
How the Bacterial Circuit Works
The researchers engineered five strains of the bacteriumPantoea agglomerans. Two strains function as biological transistors. These act like on-off switches. Three other strains act as relays. Relays pass signals between components.
The transistors respond to specific chemical signals. They detect molecules called OC-6 and OC-12. Based on these signals, the transistors produce a new molecule, OHC-14. This OHC-14 molecule then signals other parts of the circuit.
The relay strains translate the OHC-14 signal. They convert it into a form that the next transistor can understand. This connects the bacterial transistors. It allows information to flow through the circuit.
Performing Calculations
These bacterial circuits can perform basic logic operations. They can function as multi-input, OR, and IMPLY gates. The researchers built more complex circuits. These circuits could add two signals. They processed multiple signals simultaneously. One circuit acted as a demultiplexer.
The largest demonstrated circuit used 24 bacterial colonies. It successfully added two input signals. Lead author Hamid Doosthosseini stated that any operation can be built with these five bacterial strains.
Applications in Agriculture
MIT researchers aim to integrate computational abilities into living organisms. The biological circuits could be applied to plant leaves or roots. They could detect conditions like drought or pest attacks. Once detected, the circuit could trigger a response. This could include producing a substance to fight off a pest.
These biological computers are slow compared to electronic ones. Each calculation takes about eight hours. However, this speed is acceptable for biological applications. Overnight calculations are fast enough for plant growth cycles.
Dividing Labor Among Bacteria
The MIT approach divides tasks among different bacterial strains. One type of cell acts as a transistor. Other cells function as relays. This is similar to a team where each member has a specific role. This differs from single-cell engineering, which can burden a cell's machinery.
This research demonstrates that living cells can be programmed. They can perform computational functions. Connecting these cells creates larger biological circuits. The goal is to create programmable biological components for plants.
