Halobaculum

Abstract: A novel, orange-pigmented, halophilic archaeon, strain DC8T, was isolated from Urmia salt lake in north-west Iran. The cells of strain DC8T were non-motile and pleomorphic, from small rods to triangular or disc shaped. The novel strain needed at least 2.5 M NaCl and 0.02 M MgCl2 for growth. Optimal growth was achieved at 4.0 M NaCl and 0.1 M MgCl2. The optimum pH and temperature for growth were pH 7.5 and 45 °C, respectively, and it was able to grow over a pH range of 7.0 to 8.5 and a temperature range of 25 to 55 °C. Analysis of the 16S rRNA gene sequence showed that strain DC8T was a member of the family Halobacteriaceae; however, its similarity was as low as 90.1 %, 89.3 % and 89.1 % to the most closely related haloarchaeal taxa, including type species of members of the genera Halosimplex, Halobaculum and Halomicrobium, respectively. The G+C content of its DNA was 68.1 mol%. Polar lipid analyses revealed that strain DC8T contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and phosphatidic acid. One unknown phospholipid, two major glycolipids and one minor glycolipid were also detected. The only quinone present was MK-8 (II-H2). The physiological, biochemical and phylogenetic differences between strain DC8T and other extremely halophilic archaeal genera with validly published names supported that this strain represents a novel species of a new genus within the family Halobacteriaceae, for which the name Halosiccatus urmianus gen. nov., sp. nov. is proposed. The type strain is strain DC8T ( = IBRC-M 10911T = CECT 8793T).

Abstract: Halophiles are salt loving organisms that grow best at the highest salinities (3 4.5 mol L Nacl) forming dense blooms and resulting in the red colour of many brines. Common species of halobacteria are rod, cocci, or disc shaped, although triangular and even square shaped species exist. Halobacteria are classified as archea and belongs to the family halobacteriaceae. Ten genera have been reported, Halobacterium, Haloarcula, Halococcus, Haloferax, Halorubrum, Halobaculum, Natronobacterium, Natranococcus, Natrialba and Natromonas and an eleventh genus Haloterrigena has recently been proposed (Dym et al., 1995).

Abstract: A gram negative, motile, polymorph shaped, orange pigmented, extremely halophilic archaeon, designated as Strain Ea3T was isolated from hypersaline playa in central desert of Iran. Sampling was carried out in dry season and the modified growth medium (MGM) with 23% total salt concentration from Halohandbook online protocol used for the isolation procedure. Pure isolate were obtained by successively cultivations on solid MGM medium. Characterization of this strain was achieved by following the minimal standards recommended by Oren et al. (1997) for describing novel taxa of the order Halobacteriales. Strain Ea3 is a mesophilic and nutrophilic haloarchaeon , whose optimal growth temperature and pH optimum are 40 •‹C and pH 7. Optimal NaCl and Mg2+ concentrations for growth are 4 M and 0.2 M respectively. The genomic DNA of the isolate was extracted by DNA extraction kit (Roche, Germany) according to the manufacturer•fs recommended procedure and the 16S rRNA gene was PCR-amplified using the archaeal universal primers: 21F (5•Œ-TTCCGGTTGATCCYGCCGGA3•Œ) and 1492R (5•Œ-GGTTACCTTGTTACGACTT-3•Œ). Phylogenetic analysis based on 16S rRNA gene sequence analysis suggested that strain Ea3T is a member of the phylogenetic group defined by the family Halobacteriaceae, but there were as low as 90.2%, 89.6%, 89.2% and 88.9% similarities to species of other members of this family including: Halosarcina, Halopelagius, Halobaculum and Halogeometricum respectively. The G + C content of the DNA is 65.9 mol%. Polar lipid analysis revealed the presence of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulphate and three unknown glycolipid. On the basis of the data presented, we propose that strain EA3T should be placed in a new species of new genus, Haloaraneus kashanensis gen. nov, sp.nov. Reference 1Dyall-Smith M L (2008). The Halohandbook: Protocols for haloarchaeal Genetics. 259 http://www.haloarchaea.com/resources/halohandbook. 2Oren A, Ventosa A and Grant W.D(1997). Proposed minimal standards for description of new taxa in the order Halobacteriales. Int. J. Syst. Bacteriol, 47, 233-238.