Haloferax sulfurifontis sp. nov., a halophilic archaeon isolated from a sulfide- and sulfur-rich spring

Abstract

A pleomorphic, extremely halophilic archaeon (strain M6 T ) was isolated from a sulfide-and sulfur-rich spring in south-western Oklahoma (USA). It formed small (0?8-1?0 mm), salmon pink, elevated colonies on agar medium. The strain grew in a wide range of NaCl concentrations (6 % to saturation) and required at least 1 mM Mg 2+ for growth. Strain M6 T was able to reduce sulfur to sulfide anaerobically. 16S rRNA gene sequence analysis indicated that strain M6 T belongs to the family Halobacteriaceae, genus Haloferax; it showed 96?7-98?0 % similarity to other members of the genus with validly published names and 89 % similarity to Halogeometricum borinquense, its closest relative outside the genus Haloferax. Polar lipid analysis and DNA G+C content further supported placement of strain M6 T in the genus Haloferax. DNA-DNA hybridization values, as well as biochemical and physiological characterization, allowed strain M6 T to be differentiated from other members of the genus Haloferax. A novel species, Haloferax sulfurifontis sp. nov., is therefore proposed to accommodate the strain. The type strain is M6 T

Phylogenetic Diversities and Community Structure of Members of the Extremely Halophilic Archaea (Order Halobacteriales) in Multiple Saline Sediment Habitats

“…Salinity and depth vertical profile measurements have indicated that as spring water with low salinity diffuses to the banks of the stream, evaporation results in a decrease in moisture and an increase in salinity at the top soil layers, resulting in the creation of a microenvironment with higher salinity (24). Subsequently, multiple novel genera and species have been isolated from that location (25,58,59), some of which possess an exceptional ability to survive at low salt concentrations (58). As such, Zodletone Spring represents a moderate environment, well suited for the growth of mesophiles and extremely inhospitable to halophiles and where Halobacteriales survive in a distinct, narrow microenvironment within the top layers of the spring bank, which is constantly being diluted through the flowing spring water to the banks.…”

“…Members of the genus Haloferax were present at Ͼ5% in CAR and MAN samples and at up to 17% in ZDT sample ( Table 2). Members of the genus Haloferax are widely distributed in nature, ranging from salt-saturated habitats to atypical low-salinity environments, e.g., Zodletone Spring (24,25). In addition, members of the genus Haloferax are often versatile, fast-growing microorganisms that are easily obtained in pure cultures (8) and have a wide range of substrate utilization and catabolic capabilities (27).…”

“…Examples of such habitats are naturally occurring and man-made saline soils, e.g., salt plains and alpine salt sediments (10,54), soils adjacent to salt mines and salt-processing plants (44), traditional Asian salted and fermented seafood products (e.g., jeotgal) (57), deep-sea saline anoxic basins (1), and marine sponges (38). Further, multiple research groups have detected (24,43) and subsequently isolated (25,29,35,53,58,59) Halobacteriales strains from ecosystems with low salinities (1 to 3.5% NaCl), where they appear to possess exceptional survival capabilities and/or are capable of exploiting niches of relatively higher salinities created due to temporal and spatial variations in geochemical conditions in such ecosystems.…”

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon

“…Can these organisms use elemental sulfur, which may be very abundant, as the alternative terminal electron acceptor? This question was addressed several times in the past 30 years (Grant and Ross, 1986;Tindall and Trüper, 1986;Elshahed et al, 2004aElshahed et al, , 2004b, but no conclusive answer has been found. Acetate is an abundant electron donor and carbon source in anoxic habitats, which accumulates in the absence of high-potential electron acceptors, such as nitrate or ferric ion (Afshar et al, 1998;Kashevi et al, 2002;Slobodkina et al, 2009).…”

Halosarcina pallida gen. nov., sp. nov., a halophilic archaeon from a low-salt, sulfide-rich spring

“…Recently, the extent of the family has been undergoing rapid expansion, with the description (as of June 2007) of five new genera and 20 novel species since 2006. This expansion has been due not only to the identification of novel taxa isolated from well-known hypersaline environments, such as the genera Halovivax, Halostagnicola, Haloplanus and Haloquadratum (Castillo et al, 2006a, b;Bardavid et al, 2007;Burns et al, 2007), but also to the recognition that members of the Halobacteriales can grow within saline microniches in non-saline environments at relatively low salt concentrations (Elshahed et al, 2004a;Savage et al, 2007). In addition, recent studies have reported the isolation of novel halobacterial strains (Purdy et al, 2004;Fukushima et al, 2007) or the detection of novel Halobacteriales-affiliated 16S rRNA gene sequences from moderate-to low-salinity systems (Munson et al, 1997;Takai et al, 2001;Walsh et al, 2005).…”