Studies of stress resistance in a poly-extremophilic bacterium relevant to habitability studies in solar and extra solar planets

MAUAS PABLO; ALCHÉ LAURA; MAIZEL DANIELA

Atenas

Congreso; 16 Annual conference of the European Astrobiology Network Association; 2016

European Astrobiology Network Association

In the last 20 years, studies of extrasolar planets have progressed considerably, focusing on the search of planets similar to Earth and in the Habitability Zone, with a major interest in the search of evidence of life in such environments. It is readily evident that our notion of ?habitability? relies on our limited knowledge of life on Earth. Therefore, in an attempt to find posible extraterrestrial forms of life, it becomes fundamental to enlarge our knowledge about extreme life within our own planet. Such forms of life able to tolerate extreme conditions are mostly known as ?extremophiles? (Caviccioli 2002; Das Sarma, 2006). Some of these organisms have been recently proposed as models for astrobiology studies (Abrevaya et al, 2010; 2011). An interesting case of extremophiles related to the search for extraterrestrial life is represented by halophilic bacteria. These ?salt-loving? microorganisms thrive in salt concentrations which would normally prevent most organisms from living. In this context, Mars is a planet where the presence of salts has been demonstrated. Evidence for halite was found in the SNC meteorites (Gooding 1992) and their Martian origin has been confirmed independently by several groups (Treiman et al. 2000; Rieder et al. 2004). For this reason, bacteria able to survive in extremely salty environments are of interest for astrobiological studies and the search for life on Mars. Additionally, the ability of microorganisms to grow in presence of UV radiation is also considered important for astrobiology studies. Brevibacterium linens AE038-8, a bacterial strain isolated from arsenic-contaminated groundwater in Tucuman (Argentina), and previously reported as extremely resistant to arsenic compounds (Maizel et al. 2016) showed to be also capable of growing in extremely high salt concentrations. In addition, its resistance to UV radiation was also studied. In the present work we propose strain AE038-8 as an interesting prospect for studies of life on Mars and in extra solar planets.