Autonomous Pattern Formation of Micro-organic Cell Density with Optical Interlink between Two Isolated Culture Dishes.

Artificial linking of two isolated culture dishes is a fascinating means of investigating interactions among multiple groups of microbes or fungi. We examined artificial interaction between two isolated dishes containing Euglena cells, which are photophobic to strong blue light. The spatial distribution of swimming Euglena cells in two micro-aquariums in the dishes was evaluated as a set of new measures: the trace momentums (TMs). The blue light patterns next irradiated onto each dish were deduced from the set of TMs using digital or analogue feedback algorithms. In the digital feedback experiment, one of two different pattern-formation rules was imposed on each feedback system. The resultant cell distribution patterns satisfied the two rules with an and operation, showing that cooperative interaction was realized in the interlink feedback. In the analogue experiment, two dishes A and B were interlinked by a feedback algorithm that illuminated dish A (B) with blue light of intensity proportional to the cell distribution in dish B (A). In this case, a distribution pattern and its reverse were autonomously formed in the two dishes. The autonomous formation of a pair of reversal patterns reflects a type of habitat separation realized by competitive interaction through the interlink feedback. According to this study, interlink feedback between two or more separate culture dishes enables artificial interactions between isolated microbial groups, and autonomous cellular distribution patterns will be achieved by correlating various microbial species, despite environmental and spatial scale incompatibilities. The optical interlink feedback is also useful for enhancing the performance of Euglena-based soft biocomputing.