The game with the GFP receiver construct

Figure 1. Gameplay with GFP receiver construct

The receiver and sender colonies were plated in the honeycomb hexagonal pattern on LB-Agar for a timelapse experiment to follow the OHHL diffusion from sender cells to receiver cells.
The mine cells/sender cells are represented by green circles, the numbers indicate how many mines surround the non mine colonies . The grey-scale makes it easy to identify 1,2 or 3 surrounding mines. As predicted in our model a gradient is visible in the colony. This gives the player information about the location of the mine. Based on this information , the player can decide about the next move, as in to which colony the substrate needs to be added in order to move past the mines without detonating them , or to flag them.

The game with the hydrolases receiver construct

Figure 3. [OHHL] dependent information processing

1. Receiver cells respond to low OHHL levels: If one mine cell is close to a non-mine colony and by OHHL diffusion takes place to reach the non-mine colony. Due to a bandpass filter using the LuxR system in the non-mine colony,low concentrations of OHHL is detected which activates a reporter. Addition of the multi-substrate to this colony produces a salmon color and this indicates one mine is adjacent to the colony just played.

2. Receiver cells respond to high OHHL levels: If there are two or more mine colonies adjacent to a non-mine colony, a higher concentration of diffused OHHL will be processed by the receiver colony. The LuxR system works as a bandpass filter again and induces the expression of another reporter to show that 2 or more mines surround the selected colony. Addition of the nulti-substrate to this colony produces a magenta color that indicates more than two mines adjacent to this colony.

3. Receiver cells signal no mines in their vicinity. If there is no mine adjacent to a non-mine colony, no OHHL is processed. In this case, a constitutive hydrolase is expressed which on addition of the multi-substrate will give a yellow color. This indicates that there are no mines adjacent to this colony

The game play by the player

Figure 4: Gameplay

To play Colisweeper, the player has to pipette colorless substrates on a colony on the agar minefield. A single move of pipetting would require the player to choose between two colorless substrates. If the multi-susbtrate is added, this will reveal the identity of the colony- as in the number of mines surrounding a non-mine. The single colorless substrate is pipetted onto a colony if the player is certain of a mine colony. Addition of either substrates produces a defined colored product within minutes, allowing identification of the played colony and the number of mines surrounding it.

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