Taxonomic Analysis of Extremely Halophilic Archaea Isolated from 56-Years-Old Dead Sea Brine Samples (original) (raw)
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Applied and environmental microbiology, 1996
Twenty-two extremely halophilic aerobic archaeal strains were isolated from enrichments prepared from Dead Sea water samples collected 57 years ago. The isolates were phenotypically clustered into five different groups, and a representative from each group was chosen for further study. Almost the entire sequences of the 16S rRNA genes of these representatives, and of Haloarcula hispanica ATCC 33960, were determined to establish their phylogenetic positions. The sequences of these strains were compared to previously published sequences of 27 reference halophilic archaea (members of the family Halobacteriaceae) and two other archaea, Methanobacterium formicicum DSM 1312 and Methanospirillum hungatei DSM 864. Phylogenetic analysis using approximately 1,400 base comparisons of 16S rRNA-encoding gene sequences demonstrated that the five isolates clustered closely to species belonging to three different genera--Haloferax, Halobacterium, and Haloarcula. Strains E1 and E8 were closely relat...
Applied and Environmental Microbiology
Twenty-two extremely halophilic aerobic archaeal strains were isolated from enrichments prepared from Dead Sea water samples collected 57 years ago. The isolates were phenotypically clustered into five different groups, and a representative from each group was chosen for further study. Almost the entire sequences of the 16S rRNA genes of these representatives, and of Haloarcula hispanica ATCC 33960, were determined to establish their phylogenetic positions. The sequences of these strains were compared to previously published sequences of 27 reference halophilic archaea (members of the family Halobacteriaceae) and two other archaea, Methanobacterium formicicum DSM 1312 and Methanospirillum hungatei DSM 864. Phylogenetic analysis using approximately 1,400 base comparisons of 16S rRNA-encoding gene sequences demonstrated that the five isolates clustered closely to species belonging to three different genera-Haloferax, Halobacterium, and Haloarcula. Strains E1 and E8 were closely related and identified as members of the species Haloferax volcanii, and strain E12 was closely related and identified as a member of the species Halobacterium salinarum. However, strains E2 and E11 clustered in the Haloarcula branch with Haloarcula hispanica as the closest relative at 98.9 and 98.8% similarity, respectively. Strains E2 and E11 could represent two new species of the genus Haloarcula. However, because strains of these two new species were isolated from a single source, they will not be named until additional strains are isolated from other sources and fully characterized.
Halobaculum gomorrense gen. nov., sp. nov., a novel extremely halophilic archaeon from the Dead Sea
International journal of systematic bacteriology, 1995
A novel extremely halophilic archaeon was isolated from the Dead Sea. This isolate is rod shaped and, like Halobacterium sodomense, requires a relatively low level of sodium ions for growth and a very high level of magnesium; optimal growth occurs in the presence of 0.6 to 1.0 M Mg2+. The new strain resembles members of the Halobacterium saccharovorum-Halobacterium sodomense-Halobacterium trapanicum group in many physiological properties. However, the polar lipid composition of this organism is characteristic of representatives of the genus Haloferax; a sulfated diglycosyl diether is present, and the glycerol diether analog of phosphatidylglycerosulfate is absent. The G+C content of the DNA is 70 mol%. We found that on the basis of 16S rRNA sequence data our new isolate occupies a position intermediate between the position of the Halobacterium saccharovorum group and the position of the genus Haloferax and is sufficiently different from the previously described members of the Haloba...
Characterization of halophilic Archaea isolated from different hypersaline ecosystems
Annals of Microbiology, 2006
Halobacterial representatives were isolated from salted fish, naturally occurring salt pans as well as artificial saline pools in the Mediterranean area. The isolation techniques experimented proved successful, allowing halophilic archaea to be retrieved in almost 72% of analysed samples. About 65% of strains could be presumptively ascribed to the species Haloarcula marismortui by RFLP (Restriction Fragment Length Polymorphism) grouping and 16S rRNA gene sequence comparison. Nevertheless, cluster analysis of RAPD-PCR patterns revealed a wide heterogeneity among isolated strains. Biochemical features of technological interest, such as proteolytic, lipolytic and decarboxylase activity, were investigated in order to elucidate the role of archaea during ripening of salted anchovies. Proteolytic activity was only evidenced on the sarcoplasmic fraction extracted from fresh anchovies and for only 4 strains out of 21. No strain revealed either lipolytic capability on cod liver oil or proteolytic activity on fresh anchovies myofibrillar extract. Finally, only one strain exhibited decarboxylase activity, minimizing the potential responsibility of cultivable archaea microflora in the spoilage of salted anchovies.
Archaeal diversity in the Dead Sea: Microbial survival under increasingly harsh conditions
2009
The Dead Sea is rapidly drying out. The lake is supersaturated with NaCl, and precipitation of halite from the water column has led to a decrease in sodium content, while concentrations of magnesium and calcium greatly increased, making the lake an ever more extreme environment for microbial life. In the past decades, blooms of algae (Dunaliella) and halophilic Archaea were twice observed in the lake (1980-1982 and 1992-1995), triggered by massive inflow of freshwater floods, but no conditions suitable for renewed microbial growth have occurred since. To examine whether the Dead Sea in its current state (density 1.24 g ml-1 , water activity about 0.67) still supports life of halophilic Archaea, we collected particulate matter from a depth of 5 m at an offshore station by means of tangential filtration. Presence of bacterioruberin carotenoids, albeit at low concentrations, in the particulate material showed that members of the Halobacteriaceae were still present in the lake's water column. Amplification of 16S rRNA genes from the biomass yielded genes with less than 95% identity with environmental sequences reported from other environments and only 89-95% identity with cultivated Halobacteriaceae. It is thus shown that the Dead Sea, in spite of the ever more adverse conditions to life, supports a unique and varied community of halophilic Archaea. We have also isolated a number of strains of Halobacteriaceae from the samples collected, and their characterization is currently in progress.
Applied and environmental microbiology, 2015
We examined the diversity and community structure of members of the halophilic Archaea (Class Halobacteria) in samples from Central and Southern Tunisian endorheic salt lakes and sebkhet systems using targeted 16S rRNA gene diversity survey and quantitative PCR (qPCR) approaches. Twenty-three different samples from four distinct locations exhibiting a wide range of salinity (2-37%), and physical characteristics (water, salt crust, sediment, biofilm) were examined. A total of 4759 OTUs0.03 belonging to 45 currently recognized genera were identified, with 8-43 genera (average: 30) identified per sample. In spite of the large number of genera detected per sample, only a limited number (2-16) usually constituted the majority (≥80%) of encountered sequences. Halobacteria diversity showed a strong negative correlation to salinity (Pearson correlation coefficient = -0.92), and community structure analysis identified salinity, rather than location or physical characteristic of the sample, a...
Taxonomic Study of Extreme Halophilic Archaea Isolated from the “Salar de Atacama”, Chile
Systematic and Applied Microbiology, 2001
The extreme halophilic archaea require at least 1.5 M NaCl. Most strains grow best at 3.5-4.5 M NaCl. They have been isolated from different habitats including alkaline and salt lakes, marine salterns, the Dead Sea and saline soils. Traditionally the family Halobacteriaceae contains six genera: Halobacterium, Haloarcula, Haloferax, Halococcus and two alkalophilic genera, Natronobacterium and Natronococcus . Recently, applying molecular techniques nine new genera were described: Halorubrum (MCGENITY et al.
Bacillus marismortui sp. nov., a new moderately halophilic species from the Dead Sea
International journal of systematic bacteriology, 1999
A group of 91 moderately halophilic, Gram-positive, rod-shaped strains were isolated from enrichments prepared from Dead Sea water samples collected 57 years ago. These strains were examined for 117 morphological, physiological, biochemical, nutritional and antibiotic susceptibility characteristics. All strains formed endospores and were motile, strictly aerobic and positive for catalase and oxidase. They grew in media containing 5-25% (w/v) total salts, showing optimal growth at 10% (w/v). Eighteen strains were chosen as representative isolates and were studied in more detail. All these strains had mesodiaminopimelic acid in the cell wall and a DNA G + C content of 39.0-42.8 mol%; they constitute a group with levels of DNA-DNA similarity of 70-100%. The sequences of the 16S rRNA genes of three representative strains (strains 123T, 557 and 832) were almost identical (99.9%), and placed the strains in the low G + C content Gram-positive bacteria. On the basis of their features, these...
Halomonas aestuarii sp. nov., a moderately halophilic bacterium isolated from a tidal flat
International Journal of Systematic and Evolutionary Microbiology, 2017
Strain Hb3 T was isolated from a tidal flat in Jeollabuk-do Gunsan, Republic of Korea. Cells were Gram-stain-negative, oxidase-and catalase-positive, rod-shaped and motile. The strain grew optimally at 25-35 C, at pH 6.0-6.5 and with 3.0-10.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain Hb3 T belonged to the genus Halomonas. Strain Hb3 T was related most closely to Halomonas ventosae Al12 T (98.6 % 16S rRNA gene sequence similarity), Halomonas denitrificans M29 T (98.6 %) and Halomonas saccharevitans AJ275 T (98.4 %). Moreover, multilocus sequence analysis using the gyrB, rpoD and secA genes supported the phylogenetic position of strain Hb3 T. The genomic G+C content of strain Hb3 T was 67.9 mol%. DNA-DNA hybridization values for strain Hb3 T versus H. ventosae Al12 T , H. denitrificans M29 T and H. saccharevitans AJ275 T were 38.0, 54.5 and 47.4 %, respectively. The major quinone was ubiquinone Q-9 and the major fatty acids were C 18 : 1 !7c, summed feature 3 (C 16 : 1 !6c and/or C 16 : 1 !7c), C 16 : 0 and C 19 : 0 cyclo !8c. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, amino lipid, six unidentified phospholipids and an unidentified lipid comprised the polar lipid profile. On the basis of the data presented in this report, strain Hb3 T represents a novel species of the genus Halomonas. The name Halomonas aestuarii sp. nov. is proposed for this novel species. The type strain is Hb3 T (=KCTC 52253 T =JCM 31415 T).