Neptunomonas phycophila sp. nov. isolated from a culture of Symbiodinium sp., a dinoflagellate symbiont of the sea anemone Aiptasia tagetes.

A Gram-stain-negative, facultatively anaerobic, oxidase- and catalase-positive, rod-shaped bacterium, strain SYM1(T), was isolated from a culture of Symbiodinium sp., an algal symbiont of the sea anemone Aiptasia tagetes collected in Puerto Rico. Growth was observed at 4-40 °C (optimum 30 °C), at pH 5.0-11.0 (optimum pH 8.0) and with 0.5-8 % (optimum 2 %) (w/v) NaCl. Phylogenetic analyses of 16S rRNA gene sequences showed that strain SYM1(T) was a member of the genus Neptunomonas with the type strain of Neptunomonas naphthovorans as the closest phylogenetic relative with a pairwise sequence similarity of 98.15 %. However, DNA-DNA relatedness between strain SYM1(T) and N. naphthovorans CIP 106451(T) was 24 %. Moreover, strain SYM1(T) could be distinguished from its closest relative by several phenotypic characteristics such as NaCl, pH and temperature tolerance, nitrate reduction and utilization of carbon substrates. The major cellular fatty acids were C16 : 0, C18 : 1ω7c and summed feature 3 (comprising C16 : 1ω7c and/or iso-C15 : 0 2-OH). The genomic DNA G+C content of strain SYM1(T) was 45 mol%. Ubiquinone-8 (Q-8) was the only respiratory quinone detected. Based on a polyphasic taxonomic characterization, strain SYM1(T) represents a novel species of the genus Neptunomonas, for which the name Neptunomonas phycophila sp. nov. is proposed. The type strain is SYM1(T) ( = LMG 28329(T) = CECT 8716(T)).

Novel psychropiezophilic Oceanospirillales species Profundimonas piezophila gen. nov., sp. nov., isolated from the deep-sea environment of the Puerto Rico trench.

The diversity of deep-sea high-pressure-adapted (piezophilic) microbes in isolated monoculture remains low. In this study, a novel obligately psychropiezophilic bacterium was isolated from seawater collected from the Puerto Rico Trench at a depth of ∼6,000 m. This isolate, designated YC-1, grew best in a nutrient-rich marine medium, with an optimal growth hydrostatic pressure of 50 MPa (range, 20 to 70 MPa) at 8°C. Under these conditions, the maximum growth rate was extremely slow, 0.017 h(-1), and the maximum yield was 3.51 × 10(7) cells ml(-1). Cell size and shape changed with pressure, shifting from 4.0 to 5.0 µm in length and 0.5 to 0.8 µm in width at 60 MPa to 0.8- to 1.0-µm diameter coccoid cells under 20 MPa, the minimal pressure required for growth. YC-1 is a Gram-negative, facultatively anaerobic heterotroph. Its predominant cellular fatty acids are the monounsaturated fatty acids (MUFAs) C16:1 and C18:1. Unlike many other psychropiezophiles, YC-1 does not synthesize any polyunsaturated fatty acids (PUFAs). Phylogenetic analysis placed YC-1 within the family of Oceanospirillaceae, closely related to the uncultured symbiont of the deep-sea whale bone-eating worms of the genus Osedax. In common with some other members of the Oceanospirillales, including those enriched during the Deepwater Horizon oil spill, YC-1 is capable of hydrocarbon utilization. On the basis of its characteristics, YC-1 appears to represent both a new genus and a new species, which we name Profundimonas piezophila gen. nov., sp. nov.

Marinomonas ushuaiensis sp. nov., isolated from coastal sea water in Ushuaia, Argentina, sub-Antarctica.

A Gram-negative, rod-shaped, psychrophilic, motile, non-spore-forming bacterium, strain U1T, was isolated from Ushuaia located at the southernmost tip of Argentina. On the basis of 16S rRNA gene sequence similarity, strain U1T was found to be closely related to Marinomonas communis (DSM 5604T) and Marinomonas primoryensis (IAM 15010T). At the DNA-DNA level, however, the values for similarity were 41 and 25 %, respectively. The major fatty acids present were iso-C(16 : 0), C(16 : 1)omega7c, iso-C(17 : 1) and C(18 : 1)omega7c and the G+C content of the DNA was 43.6 mol%. All of the above characteristics support the affiliation of strain U1T to the genus Marinomonas. Furthermore, on the basis of phenotypic features, chemotaxonomic characteristics and phylogenetic analysis of the 16S rRNA gene sequence, it appears that strain U1T is distinct from the four Marinomonas species with validly published names. Strain U1T, therefore, represents a novel species, for which the name Marinomonas ushuaiensis sp. nov. is proposed. The type strain of M. ushuaiensis is U1T (=MTCC 6143T=DSM 15871T=JCM 12170T).