| Congresso Brasileiro de Microbiologia 2023 | Resumo: 458-1 | ||||
Resumo:ABSTRACT: Extremophile microorganisms are able to withstand and thrive in a wide range of extreme conditions, some of which are analogous to the ones found in other planets. The study of the unique features of these living beings, their biosignatures, can also assist in the search and recognition of traces of life outside of Earth. This makes them an essential subject of study to answer one of the most ancient inquiries of the human race and one of the main questions of Astrobiology: “Are we alone in the Universe?”. This project aims to help this quest by isolating and analyzing two aspects of halophilic bacteria found in the hypersaline lagoons Lagoa Vermelha and Brejo do Espinho, Araruama, RJ - Brazil: their survival capability in extreme conditions and their potential to precipitate carbonate compounds, which can be related to important biosignatures. To ensure a broad coverage of representative organisms, we collected samples from three locations of the lagoons with different environmental conditions. Organisms were isolated in hypersaline MLV mediums with 8%, 10% and 12% NaCl concentrations, resulting in a total of 44 bacterial isolates. A first batch of these isolates were further cultivated for one month to assess their ability to precipitate carbonate compounds. Aliquots and pH measurements were collected weekly, and the latter showed medium alkalinization in three of the isolates, which could facilitate the bioprecipitation activity. At the end of the month, dried precipitates from these cultures were collected and, together with the weekly aliquots, are now undergoing analysis by Raman spectrometry, x-ray diffraction and scanning electron microscopy to determine the nature of their compositions and ascertain the presence of biogenic carbonate compounds. The viability of the organisms under exposure to ultraviolet radiation (UV) and desiccation is going to be evaluated separately by counting of colony forming units. One of the selected isolates presented optimal growth after a desiccation process, with an average of 3,4.105 CFU/mL after 4 days. Finally, they will be subjected to an environmental simulation of current Mars, with the extreme simultaneous conditions of the differential atmosphere composition, pressure, temperature and UV radiation, conducted in the AstroCam equipment from the Institute of Chemistry of the University of São Paulo. Organisms that present optimal results will be identified through 16s sequencing. The current preliminary results point to the possibility of there being multiple bacteria in the hypersaline lagoons with astrobiological potential. It is expected that further results assist with determining organisms capable of thriving in the extremes found on Mars or other planets of interest, as well as ones that could elucidate new studies in biosignatures to help in the recognition of biogenic features in future explorations.
Palavras-chave: ASTROBIOLOGY, BIOSIGNATURE, EXTREMOPHILE, HALOPHILIC, HYPERSALINE | |||||