Exiguobacterium pavilionensis str. N139, a halotolerant, UV-B and metal resistant bacteria from a high-altitude Andean lake

Abstract

We report the genome sequence of Exiguobacterium pavilionensis str. N139, isolated from a high-altitude Andean lake. The 2,952,588-bp genome contains one chromosome and three megaplasmids. The genome analysis suggests the presence of enzymes that confer E. pavilionensis str. N139 the ability to grow under multiple environmental extreme conditions, including high concentrations of different metals and high ultraviolet B radiation. Moreover, the regulation of its tryptophan biosynthesis suggests that novel pathways remain to be discovered, and that these pathways might be fundamental in the amino acid metabolism of the microbial community from Laguna Negra, Argentina . We report the genome sequence of Exiguobacterium pavilionensis str. N139, isolated 29 from a high-altitude Andean lake. The 2,952,588-bp genome contains one chromosome and three 30 megaplasmids. The genome analysis suggests the presence of enzymes that confer E.31 pavilionensis str. N139 the ability to grow under multiple environmental extreme conditions, 32 including high concentrations of different metals and high ultraviolet B radiation. Moreover, the 33 regulation of its tryptophan biosynthesis suggests that novel pathways remain to be discovered, 34 and that these pathways might be fundamental in the amino acid metabolism of the microbial 35 community from Laguna Negra, Argentina. The high altitude Andean Lakes (HAALs) from Puna, Argentina, are a group of lakes 53 located at 3000-6000 meters above sea level which are characterized by high ultraviolet (UV) 54 radiation and salinity, broad temperature variations, low nutrient concentrations and high 55 contents of metals and metalloids, mainly arsenic (Fernández-Zenoff et al., 2006; Fernández-56 Zenoff, Siñeriz & Farías, 2006;Dib et al., 2008;Ordoñez et al., 2009; 57 Albarracín et al., 2011; Belfiore, Ordoñez & Farías, 2013). These environmental conditions are 58 considered to be extreme and might resemble those of the Earth's early atmosphere, as has been 59 stated by NASA (Cabrol et al., 2007;Farías et al., 2009). Hence, these geographical areas have 60 been proposed for studies on astrobiology . Despite being oligotrophic and 61 hostile, a great microbial diversity has been found in the HAALs, where bacteria from the genus 62 Exiguobacterium are one of the dominant taxa (Ordoñez et al., 2009(Ordoñez et al., , 2013Sacheti et al., 2013). 63The Exiguobacterium genus, a sister clade to the Bacillus genus, is currently 64 underexplored, and molecular studies of this genus from different sources are limited 65 (Vishnivetskaya, Kathariou & Tiedje, 2009 Figure 1A shows the phylogenetic reconstruction of 147 all Exiguobacterium species from both clades. These analyses placed the strain N139 as most 148 similar to E. pavilionensis str. RW-2 (White III, Grassa & Suttle, 2013), which is coherent with 149 the average nucleotide identity (ANI) analyses (see below). ANI calculations were done for 150 N139 versus all other complete genomic sequences of Exiguobacterium, and these two strains, 151 along...

The potential of cyanobacterium Nostoc sp. as the primary producer in the life-support system on Mars

“…Intermediate steps in purine biosynthesis are based on R5P, so this molecule also plays a key role in purine repair pathways (Kappock et al, 2000). In ribose transport systems, RbsB binds ribose in the periplasm and transports it to the membrane protein RbsC, which then binds to the cytoplasmic protein RbsA (Gutiérrez-Preciado et al, 2016). In this study, we found that the rbsC gene was signi cantly upregulated after exposure to Mars-like radiation ( ight group), which indicates that ribose transport was enhanced to promote the synthesis of R5P.…”