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Already in the early stages of designing our project, we made use of modeling to guide us in designing the experimental part. Modeling provides a look into theoretical parts of the design and provides an evaluation of possible bottlenecks in the design. We used ordinary differential equation (ODE) and agent-based (AB) models, each best fit to the specific concerns. These models supported us in choosing the enzymes for melanin production and the design approaches to test in experiments and showed which results could be expected when different modifications were introduced.e?
To address the problems of long-term space exploration and subsequent planetary colonization we wanted to provide a biologically sustainable solution of protecting the crew of the spacecraft during the flight or being a biological benchmark for a macro- and micronutrient production. Yeast have shown to be great candidates for sustaining IR conditions (Dadachova & Casadevall, 2008). This allowed us to explore the possibility of using yeast for our intended purposes.
Space exploration has always attracted humans, fed their curiosity and need for discovery. From times of Hipparchus [Hipparchus portrait, put it on the side] to modern times we strived to look farther into our vast universe. However, the inconceivable size of the universe and the harsh environments of space limit our capabilities for futher exploration and extraterrestrial life.
Ionizing radiation (IR) is one of the space danger factors. It possesses detrimental effects on cells since it may damage the sensitive molecules. One of the most significant threats that a cell may encounter by the exposure to IR, is DNA damage. Exposure to excessive amount of ionizing radiation might results in severe damage, like chromosomal aberrations and genome instability that can not be fixed by DNA repair system, adversely affect homeostasis, and can lead to serious consequences such as acute radiation cell death or tumorigenesis in multicellular organisms. Moreover, IR affects expression of certain stress response genes that reduces cell ability to adapt to the present extreme conditions. It, in turn, may adversely alter metabolic process of the cell. (Casadevall et al., 2017). Thus, the probelm of carcinogenesis is o
To address the problems of long-term space exploration and subsequent planetary colonization we wanted to provide a biologically sustainable solution of protecting the crew of the spacecraft during the flight or being a biological benchmark for a macro- and micronutrient production. Yeast have shown to be great candidates for sustaining IR conditions (Dadachova & Casadevall, 2008). This allowed us to explore the possibility of using yeast for our intended purposes.
Several other iGEM teams have explored the prospects of melanin production. Such teams, as Cambridge 2009, PITT 2014, Stanford-Brown 2016, Sao Carlos-Brazil 2019 and Shanghai SFLS SPBS 2020 have all worked with melanin in their projects. While Cambridge, Stanford-Brown and Shanghai SFLS SPBS worked with melanin in Escherihia Coli and team PITT with Propionibacterium acnes, only team Sao Carlos-Brazil have worked with S. Cerevisiae. Sao Carlos-Brazil has specifically shown the success in using Aga2 yeast biosisplay system for fixating melanin on the outer cell membrane. Such construct was used in our third strategy described in our Design (Design Link) However, the strain required supplemented melanin in its medium. Our project is a more independent strain, requiring now supplemented melanin.
Over the years, several species of fungi have been already sent to space to study their behaviour and changes they underwent in such an environment.These experiments help to shed light on the possible consequences of long stay under conditions of elevated IR, mechanisms of cancer development and adaptive abilities of the cells in the space. Yeast are among the most favorite organisms for the scientists to be sent to space because they are well-studied single-cellular eukaryotic organisms, easy to maintain, they can survive extreme drying. In addition, many essential cellular processes are similar in yeast and humans. Yeast were first lunched to space with the Apollo 16 mission in 1972 (Taylor et al., 1975). Artemis 1 mission that is expected to launch in November 2022, will carry 6,000 mutant yeast strains. The mission will last 42 days and include orbiting around the moon. Yeasts will be exposed to radiation 10 to 20 times higher of allowable amount for any terrestrial exposure. (Space yeast rises to the occasion again, Steve McKinley)