Idiomarina baltica sp. nov., a marine bacterium with a high optimum growth temperature isolated from surface water of the central Baltic Sea

Abstract

Idiomarina baltica sp. nov., a marine bacterium with a high optimum growth temperature isolated from surface water of the central Baltic Sea Two bacterial strains isolated from the Baltic Sea, OS145 T and OS146, were characterized on the basis of their physiological and biochemical features, their fatty acid profiles and their phylogenetic position based on 16S rDNA sequence analyses. The strains were isolated from the upper oxic water column of the central Baltic Sea. Phylogenetic analyses of the 16S rDNA gene sequences revealed a clear affiliation of the novel strains with members of the genus Idiomarina, of the Gammaproteobacteria. Closest sequence similarity was seen with Idiomarina abyssalis and Idiomarina zobellii (95-96 %). The mean G+C content of the DNA of strains OS145 T and OS146 was 49?7 mol%. Both strains were non-pigmented, Gram-negative, polarly flagellated organisms that were strictly aerobic. Growth of the strains was observed at salinities ranging from 0?8 to 10 % NaCl. Temperature range for growth was rather broad and high for marine bacteria: both strains grew between 8 and 46 ‡C, showed good growth between 20 and 44 ‡C, and had an optimum between 30 and 40 ‡C. The fatty acids of the two strains were dominated by iso-branched fatty acids (54-80 %), with a high abundance of C 15 : 0 iso (36 %), C 16 : 1 v7c , C 17 : 0 iso and C 17 : 1 iso v9c . Growth temperature (8-40 ‡C) influenced the fatty acid composition of the strains in a way that the content of iso-branching fatty acids increased with increasing temperatures, while the mono-unsaturated fatty acids increased with decreasing temperatures. Salinity (1?7-10 % NaCl) had only a minor effect on the fatty acid composition. According to their morphology, physiology, fatty acid composition and 16S rDNA sequences, strains OS145 T and OS146 fitted well into the genus Idiomarina, but could be easily distinguished from the recognized species of the genus. Because of their unique nature, it is proposed that the strains isolated from the Baltic Sea represent a novel species, for which the name Idiomarina baltica (type strain OS145 T =DSM 15154 T =LMG 21691 T ) is proposed. INTRODUCTIONAt the time of writing, the genus Idiomarina contained two species, Idiomarina abyssalis and Idiomarina zobellii, of strictly aerobic Gammaproteobacteria, which were isolated from deep-sea samples from the northwest Pacific Ocean (Ivanova et al., 2000). Comparison of the 16S rRNA gene sequences of these two species with those of submitted sequences of clones and isolates showed that related sequences were derived from deep-sea sediments, with sequences from a hydrothermal mound of the Mid-Atlantic Ridge showing the highest similarity, while those of Pacific deep-sea organisms were more distantly related.An eminent feature of the genus Idiomarina is the unique composition of its fatty acids, with a high percentage of iso-branched fatty acids. Strains OS145 T and OS146, isolated from the central Baltic Sea, have an unsaturated iso-branched fatty acid (C 17 : 1 iso v9c , 8...

Idiomarina loihiensis sp. nov., a halophilic -Proteobacterium from the Lo'ihi submarine volcano, Hawai'i

“…Significant phenotypic differences extended to cell morphology, carbon sources utilized and NaCl tolerance (Tables 1 and 2). The response of L2-TR T to salinity differed markedly from those of the three described Idiomarina species (Ivanova et al, 2000;Brettar et al, 2003), each of which has an optimum salinity range for growth of 3-6 % (w/v). Although Idiomarina baltica was tested only to 10 % (w/v) NaCl (Brettar et al, 2003), strain L2-TR T appeared to have the highest optimum salinity for growth and to be the species in this genus with the broadest salinity range for growth.…”

“…Indeed, anteisobranched fatty acids comprised <1 % of the total fatty acid pool. The taxonomic significance of the fatty acid composition of Idiomarina species is discussed by Brettar et al (2003). L2-TR T appears to be unique in this genus, however, with twice the percentage of saturated fatty acids that has been reported for I. zobellii and I. baltica and~50 % more than that reported for I. abyssalis (Table 2).…”

Metal reduction at cold temperatures by Shewanella isolates from various marine environments

“…It is interesting that the optimum growth temperature for each isolate is above the in situ temperature of the environment from which it was recovered, indicating that these organisms have adapted to their current living conditions. Brettar et al (2003) recently reported on the isolation of Idiomarina baltica, a marine bacterium from the Baltic Sea that demonstrated growth over a wide range of temperatures, with the optimum growth occurring between 20 and 44°C. The higher temperature tolerance of PV-4 and its ability to reduce metal is interesting in view of its origin.…”

Aliidiomarina taiwanensis gen. nov., sp. nov., isolated from shallow coastal water

“…However, the species of Pseudidiomarina were recently reassigned to the genus Idiomarina (Taborda et al, 2009) because of the difficulty in differentiating the two genera by phenotypic characteristics. At the time of writing, the genus Idiomarina accommodated 16 species, Idiomarina abyssalis (Ivanova et al, 2000), I. baltica (Brettar et al, 2003), I. fontislapidosi (Martínez-Cánovas et al, 2004), I. loihiensis (Donachie et al, 2003), I. ramblicola (Martínez-Cánovas et al, 2004), I. seosinensis (Choi & Cho, 2005), I. zobellii (Ivanova et al, 2000), I. insulisalsae, I. taiwanensis, I. homiensis, I. marina, I. salinarum, I. sediminum and I. tainanensis (Taborda et al, 2009), and I. donghaiensis and I. maritima (Wu et al (2009); the latter eight formerly belonged to the genus Pseudidiomarina. Members of the genus Idiomarina have been isolated from saline habitats with a wide range of salinity, such as coastal and oceanic waters, coastal sediments, inland hypersaline wetlands, solar salterns and submarine hydrothermal fluids.…”