Variation on the pigments' profile from bacteria Deinococcus radiodurans under extreme environmental conditions applied to biosignatures in astrobiology

Abstract

The polyextremophile microorganism Deinococcus radiodurans is widely studied due to its high resistance to ionization radiation, being a model organism in Astrobiology and in the search for life in other planets. One of its several strategies of protection against radiation is the production of photoprotective pigments, which protects not only against UV-radiation, but also against oxidative environments. In this case, there are more than 10 different carotenoids in this microorganism, being deinoxanthin the carotenoid in major concentration in D. radiodurans. Due to its participation in protecting bacteria exposed to oxidative environments and with high UV-radiation incidence, these carotenoids have been suggested as biosignatures, i. e., indicatives of biological activities, in missions searching for life in Mars and, in the near future, in other planets and moons. In this project, the profile of all carotenoids (both in higher and lower concentrations) will be studied using liquid chromatography a standard culture (cultivation in mild environmental conditions) and in samples exposed to extreme conditions such as radiation and oxidative stress, simulating mars conditions. The changes in the metabolism related to the carotenoid these simulated extraterrestrial conditions will be analyzed, aiming to understand its behavior as biosignatures.