Information processing

The agar minefield consists of colonies in a hexagonal grid with mine and non-mine colonies. We have two bacterial strains: 1. the mine strain which are the sender cells and 2. the non-mine strain which are the receiver cells. The cells communicate through diffusion of OHHL and change color to give the player information in order to logically carry out the next move in the game. The colonies remain white as seen on the agar plate until any substrate is added. The left and the right click of the mouse is simulated with the addition of the multi-substrate mix and the single substrate respectively.

Figure 1: Signal transduction from secreted signaling molecule to colorimetric response. The signal diffuses through the agar from sender cells (Light blue) to receiver cells (dark grey). The non-mine colonies are designed to distinguish between different concentrations of OHHL and translate this information into expression of different sets of hydrolases. They are equipped with mutated LuxR promoters with different OHHL sensitivities which serve as highpass filters. After an incubation time of 12 hours the player interacts by pipetting substrates on the colonies. The hydrolase convert the substrate to a colored product which is visible by eye

The biology is explained here. The sender colony secretes the quorum sensing molecule 3-oxo-N-hexanoyl-L-homoserine lactone (OHHL) that diffuses through the agar to the surrounding cells. The receiver cells passively take up the OHHL by diffusion where the signaling molecule forms a complex with the inactive LuxR to activate it. The information is translated via mutated pLuxR promoters of different OHHL affinities which leads to the secretion of different hydrolases. Within minutes after the addition of substrate a change in color indicates the identity of the played colony and number of surrounding mine colonies.

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