Research & Design In the process of designing our own microcosm of Lake Malawi, we followed inspiration from the methods and conditions of a research study that mimicked rice paddy fields in Africa (Akpodiete et al 21). The data on pH, sedimentation, salinity, temperature, general hardness, and carbonate hardness of Lake Malawi were recorded from the ILEC world lake database (Massangi et al 22).

Build We simulated the water conditions of a pH of 8.0, sedimentation, MgSO₄ · 7H₂O for general hardness of 7 degrees, K₂CO₃ for a carbonate hardness of and maintained a temperature of around 25°C. Water from the microcosm was sourced and plated in CM Broth with Galactose minus URA plates before, immediately after, 3 hours after, and 24 hours after insertion of W303 yeast.

Test There was zero growth observed on all four plates.



Learn We rationalized that the lack of growth was due to the use of yeast plates without URA. Uracil is an auxotrophic marker that the mutant yeast strains have knocked out, meaning they need it in the plate in order to survive. Furthermore, the method of repeating 50mg steps of MgSO₄ · 7H₂O and K₂CO₃ and then verifying the carbonate and general hardnesses using a commercial API GH and KH test kit leaves variability in GH and KH degrees.

Research & Design Instead of relying on the step by step method of checking the GH and KH levels, we switched to a predetermined amount of K₂CO₃ and MgSO₄ · 7H₂O by calculating concentration to hardness degree ratios.

Build We reconstructed the microcosm following the same protocols as before, however, adding in 652.60mg of MgSO₄ · 7H₂O and 1026.22mg K₂CO₃. CM Broth plates were used for sampling before, immediately after, 24 hours after, and 48 hours after insertion of W303 yeast.

Test The results indicated similar positive growth at all times recorded after the insertion of W303 yeast.



Learn It can be observed with confidence that SchistsoGONE is capable of surviving the environmental conditions in Lake Malawi simulated to the best of our material capabilities.

To further accurately confirm if SchistoGONE is capable of operating in target environments, we plan to break past our material limitations from this year of iGEM. This would involve testing the fully assembled sanguinarine-producing W303 yeast and E.coli constructs to be tested in microcosms constructed with sedimentation, water, and other conditions—conductivity, oxygenation—naturally sourced from the target geographies, or potentially implemented in on-site field tests.

Akpodiete, N. O., & Tripet, F. (2021). Laboratory and microcosm experiments reveal contrasted adaptive responses to ammonia and water mineralisation in aquatic stages of the sibling species Anopheles gambiae (sensu stricto) and Anopheles coluzzii. Parasites & Vectors, 14(1), 1-19.

Massangi, A. V., (2022). Lake Malawi. World Lake Database : International Lake Environment Committee Foundation (ILEC),
wldb.ilec.or.jp/Display/html/3594.