For this part, we thoroughly considered the application of our project in the actual situation, and discussed these issues with our teachers and experts from with different professional expertise biological companies. Here are our conclusions.
We discussed with Professor Zhao Min who is a microbiologist. He suggested us to fix Leaders A, B and C together to enrich fatty acids in the vicinity of Leader C. When Leaders A, B and C are fixed together, followers can swim to Leader A because of the attraction by its secreted serine, which is equivalent to swimming to Leader C. We displayed our results of this part on the “Leaders” page. In this case, each Leader colony consists of three Leaders simultaneously, and can secrete both leucine and serine, which are repellant and attracter to Followers, respectively. When Leaders start to secrete amino acids continuously, it would generate a concentration gradient of the amino acids centered to the Leader colonies where the concentration is the highest with gradual reduction towards the edge. This may well control the movement of Followers.(Results_Leaders)
When we discussed with experts of a biological company, they pointed out that whether the chemotaxis is interfered is one of the key factors for the success of our system. Based on this advice, we designed Leaders A and B as the command center with regulatable production of the two amino acids through the relative amounts of two Leaders. We determined the optimal amino acid concentrations that gave the best chemotaxis in our experiments. This could be achieved by adding corresponding amounts of Leaders and making the chemotactic effects of serine from Leader A dominant to the anti-chemotactic effect of leucine from Leader B(Results_Leaders).
Because our case has obvious advantages under the situation with low concentrations of substrate and in large areas with static water, the anti-chemotactic effect of Leader B would disperse followers into a large range of water area even in a low concentration of leucine to collect substrate. Substrate in sewage would gather around the reaction center even in a low concentration to improve the speed and efficiency of reaction. When we discussed these thoughts with Rui Zang teacher in the Collage of Science, NEFU, he suggested us to seek for more options to improve the substrate enrichment capability of our system(Results_Followers).
This project is just an example of this new system. After discussing with our faculty from different disciplines and experts of biological companies, we recognized that this model of system is applicable to the enrichment of different substrates in various aqueous environment, if we modify reaction centers (Leaders) and substrate collectors (Followers). For example, heavy medal ions in polluted water can be collected and accumulated in Leaders. In addition, enriched fatty acids in Leader C can be processed by industrial strains that may convert them to fatty alcohol (Results_Followers), etc.