Halorubrum chaoviator sp. nov., a haloarchaeon isolated from sea salt in Baja California, Mexico, Western Australia and Naxos, Greece

Abstract

Three halophilic isolates, strains Halo-G*T, AUS-1 and Naxos II, were compared. Halo-G* was isolated from an evaporitic salt crystal from Baja California, Mexico, whereas AUS-1 and Naxos II were isolated from salt pools in Western Australia and the Greek island of Naxos, respectively. Halo-G*T had been exposed previously to conditions of outer space and survived 2 weeks on the Biopan facility. Chemotaxonomic and molecular comparisons suggested high similarity between the three strains. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the strains clustered with Halorubrum species, showing sequence similarities of 99.2–97.1 %. The DNA–DNA hybridization values of strain Halo-G*T and strains AUS-1 and Naxos II are 73 and 75 %, respectively, indicating that they constitute a single species. The DNA relatedness between strain Halo-G*T and the type strains of 13 closely related species of the genus Halorubrum ranged from 39 to 2 %, suggesting that the three isolates constitute a different genospecies. The G+C content of the DNA of the three strains was 65.5–66.5 mol%. All three strains contained C20C20 derivatives of diethers of phosphatidylglycerol, phosphatidylglyceromethylphosphate and phosphatidylglycerolsulfate, together with a sulfated glycolipid. On the basis of these results, a novel species that includes the three strains is proposed, with the name Halorubrum chaoviator sp. nov. The type strain is strain Halo-G*T (=DSM 19316T =NCIMB 14426T =ATCC BAA-1602T).

Halolamina pelagica gen. nov., sp. nov., a new member of the family Halobacteriaceae

“…These values are within the range of values reported for Halogranum (Cui et al, 2010a) and Halorubrum Mancinelli et al, 2009) and higher than Hns. pteroides (58 mol%) (Burns et al, 2010), but lower than the value reported for Hbl.…”

Halorubrum halodurans sp. nov., an extremely halophilic archaeon isolated from a hypersaline lake

“…The major polar lipids are C 20 C 20 and sometimes C 20 C 25 Modern classification of the haloarchaea requires using phenotypic characterization, a chemotaxonomic approach based on the polar lipid composition as well as comparison of the 16S rRNA gene sequence, which is considered a universal phylogenetic and taxonomic molecular marker (Oren, 2012). The usefulness of this molecular marker, however, is questionable for haloarchaeal taxonomic studies as, over the years, studies have demonstrated that it has many qualities that make it difficult to distinguish species, such as: recombination between genera (Boucher et al, 2004;Papke et al, 2015) and closely related species (Papke et al, 2004(Papke et al, , 2007; that high sequence conservation does not discriminate between closely related species (Pesenti et al, 2008;Mancinelli et al, 2009); that their rRNA operons undergo intragenic recombination (Boucher et al, 2004); and that many genera (e.g. Haloarcula, Halosimplex and Halomicrobium) contain multiple gene copies with more than 5 % sequence divergence (Boucher et al, 2004).…”

Space Microbiology

“…Increasing loss of water due to vacuum exposure leads to partial denaturation of the DNA (64). The consequences are DNA strand breaks, which have been identified in cells of D. radiodurans and Halo-G, now identified as Halorubrum chaoviatoris (159), as well as in spores of B. subtilis, after exposure to space vacuum (55,56,158). Spores of the triple mutant repair-deficient strain TKJ 8431 (uvrA10 ssp-1 recA1) of B. subtilis, which are deficient in recombination repair, were the most sensitive specimens under conditions of space vacuum (115).…”