A study was made of 516 randomly selected isolates of moderately halophilic bacteria from solar salterns showing salinities between 8.8 and 40.0% (w/v) total salts, located in S.E. Spain. After purification, many cytological, physiological, biochemical, nutritional and an ti biot ic sensitivity characters were determined for 106 selected saltern isolates and two reference strains. Data were coded and analysed by numerical techniques using the Jaccard coefficient ( S J ) , and clusters of strains were obtained by average linkage (UPGMA) analysis. Nine major phenons were found at the 72.5 % similarity level. The properties of each phenon are given, their taxonomic affinities are discussed, and typical reference strains are suggested. Almost all the strains were related to genera known to contain marine species. A large number of the strains could be tentatively assigned to the genus Vibrio, suggesting that this may be an abundant taxon of moderately halophilic Gram-negative rods in solar salterns.

No abstract

A total of 132 moderately halophilic bacteria were isolated from hypersaline soils with a C1-content between 2-36 and 12.72% (w/v) located near Alicante (S.E. Spain) and examined for 98 phenotypic characteristics including their response to cytological, physiological, biochemical and nutritional tests. They were submitted to a numerical analysis together with six reference strains using both simple matching (SsM) and Jaccard (S,) coefficients, and cluster analysis was carried out by the unweighted pair group method of association (UPGMA), single linkage and complete linkage. With the S, coefficient and UPGMA clustering, eight phenons were obtained at the 65% similarity level. From each phenon representative strains were chosen for the determination of DNA base composition and for electron microscopy. Bacteria belonging to phenons D, E, and F were assigned to the genus Alcaligenes. Phenon G included 27 strains assigned to Acinetobacter, but the high G + C composition (58.9 mol%) of a representative strain of this phenon suggests that it may represent a new taxon. Phenons A, B, and C were designated Flavobacterium and phenon H was Pseudomonas. The bacteria found in these environments are not related to those from hypersaline waters or normal soils.

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.

Gracilibacillus orientalis sp. nov., a novel moderately halophilic bacterium isolated from a salt lake in Inner Mongolia, China and EJ-15, were isolated from two salt lakes located near Xilin Hot and Ejinor, in Inner Mongolia, China. The strains were strictly aerobic and motile, with spherical, terminal and deforming endospores. They grew at pH 5?0-9?0 (optimal growth at pH 7?5), between 4 and 45 6C (optimal growth at 37 6C) and at salinities of 1-20 % (w/v) total salts, growing optimally at 10 % (w/v) salts. They had meso-diaminopimelic acid in the cell wall peptidoglycan and DNA G+C contents of 36?1-37?1 mol%. The polar lipid pattern of strain XH-63 T , selected as the representative strain, consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and a phospholipid and two amino phospholipids of unknown structure. This strain possessed anteiso-C 15 : 0 and anteiso-C 17 : 0 as the major fatty acids (altogether representing 72?5 % of total) and MK-7 as the major menaquinone. 16S rRNA gene analysis of the three strains showed that they were within the Gracilibacillus cluster, with highest sequence similarity (95?4-95?8 %) with Gracilibacillus dipsosauri. Based on a combination of phenotypic, chemotaxonomic and phylogenetic features, it is proposed that the three isolates represent a novel species of the genus Gracilibacillus, Gracilibacillus orientalis sp. nov. The type strain is strain XH-63Moderately halophilic bacteria that grow optimally in media containing 3-15 % (w/v) salts are widely distributed in different saline habitats (Ventosa et al., 1998). Taxonomically, they are a very heterogeneous physiological group, including both Gram-positive and Gram-negative microorganisms. Aerobic, spore-forming, moderately halophilic, Gram-positive rods are also taxonomically diverse and have been isolated from saline environments such as soils and aquatic habitats (Arahal & Ventosa, 2002). They were originally assigned to the genus Bacillus, but molecular and chemical analyses have shown that they form several phylogenetically distinct lineages within the group classically defined as the genus Bacillus (Ash et al. , 1991;Stackebrandt & Liesack, 1993; Nielsen et al., 1994). To date, moderately halophilic bacterial species are present in the genera Bacillus (Ventosa et al., 1989), Halobacillus (Spring et al., 1996Yoon et al., 2003), Virgibacillus (Heyndrickx et al., 1998; Arahal et al., 1999 Arahal et al., , 2000Heyrman et al., 2003), Gracilibacillus (Wainø et al., 1999)