Week 6

Tuesday, June 12

We had spend the first week of June researching carbohydrate and lipid synthesis in Chlamy, we first thought that we could develop a biosensor and were keen on monitoring carbohydrate or lipid accumulation in algae. We believe that if there could be a simple indication of whether algae are accumulating lipids or carbohydrates, biomass could be harvest on one point or the other. This could be particularly interesting for bioprocess where the final point is to achieve the highest-level o lipid accumulation. However, as there where no bricks in the registry for use in algae we decided to put the biosensor project on hold and to start by building bricks that could in the future allow us to accomplish this project. We had a brainstorming session to think on what could be the best contributions for algae we could work in. We had many ideas but the following where the most solid: • Develop a strong promoter to drive the expression of recombinant protein in Chlamy chloroplast. • Develop an inducible promoter that can be use to drive the expression of enzymes involved in the synthesis or carotenoids • Make algae that emit luminescence at night and during the day use C02 and light to grow and replenish energy molecules If the promoter responds to light and use the luminescence gene could be self-sustaining production of light, or may not require use of external light?. Question: carotene synthesis occurs in chloroplasts? If so: Does it depend on the light?

Thursday, June 14

We spent this day discussing what strong promoters we could use to drive the expression of recombinant proteins. We first thought that as Chlamy is a photosynthetic organism we could use promoters that respond to different types of light. We use part of the day to investigate about the psbA and psbD promoters and found that the psbA promoter was strong but the D1 protein (the psbA product) somehow regulated the translation of its mRNA. The psbD promoter is not as strong as the psbA but responds to blue light. One thing was clear from this point, if we wanted to achieve high levels of protein accumulation, we needed a high level of mRNA accumulation free of any translation initiation regulator. We also came to the conclusion of using the lacI/Plac regulation to drive the expression of a fluorescet protein. With this we wanted to test how this inducible and well-characterized circuit behave in Chlamy chloroplast.

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