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A novel marine bacterial strain, PV-4T, isolated from a microbial mat located at a hydrothermal vent of Loihi Seamount in the Pacific Ocean, has been characterized. This micro-organism is orangey in colour, Gram-negative, polarly flagellated, facultatively anaerobic and psychrotolerant (temperature range, 0–42 °C). No growth was observed with nitrate, nitrite, DMSO or thiosulfate as the electron acceptor and lactate as the electron donor. The major fatty acid detected in strain PV-4T was iso-C15 : 0. Strain PV-4T had ubiquinones consisting mainly of Q-7 and Q-8, and possessed menaquinone MK-7. The DNA G+C content of the strain was 53.8 mol% and the genome size was about 4.5 Mbp. Phylogenetic analyses based on 16S rRNA gene sequences placed PV-4T within the genus Shewanella. PV-4T exhibited 16S rRNA gene sequence similarity levels of 99.6 and 97.5 %, respectively, with respect to the type strains of Shewanella aquimarina and Shewanella marisflavi. DNA from strain PV-4T showed low mean levels of relatedness to the DNAs of S. aquimarina (50.5 %) and S. marisflavi (8.5 %). On the basis of phylogenetic and phenotypic characteristics, the bacterium was classified in the genus Shewanella within a distinct novel species, for which the name Shewanella loihica sp. nov. is proposed. The type strain is PV-4T (=ATCC BAA-1088T=DSM 17748T).

A novel, thermophilic, obligately chemolithoautotrophic, sulfur/thiosulfate-oxidizing bacterium was isolated from subsurface geothermal aquifer water (temperature approximately 70 °C) in the Hishikari gold mine, Japan. Cells of the isolate, designated strain C55T, were motile, straight rods with a single polar flagellum. Growth was observed at temperatures between 35 and 62 °C (optimum 50–55 °C; 60 min doubling time) and pH between 5·2 and 7·7 (optimum pH 6·5–7·0). High growth rate of strain C55T was observed on either thiosulfate or elemental sulfur as a sole energy source, with molecular oxygen as the only electron acceptor. None of the organic compounds tested supported or stimulated growth of strain C55T. The G+C content of the genomic DNA was 66·9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain C55T was affiliated to the β-Proteobacteria, but was distantly related to recognized genera. On the basis of its physiological and molecular properties, strain C55T (=JCM12421T=DSM 16629T=ATCC BAA-941T) is proposed as the type strain of Thiobacter subterraneus gen. nov., sp. nov.

A novel thermophilic, acidophilic bacterium, designated strain Pd55T, was isolated from a self-temperature-recordingin situcolonization system deployed in a hydrothermal diffusing flow (maximum temperature of 78 °C) at the TOTO caldera in the Mariana Arc. Cells of strain Pd55Twere motile, short rods with a single polar flagellum. Growth was observed between 30 and 68 °C (optimum growth at 50 °C; 120 min doubling time) and between (initial) pH 4·2 and 7·0 (optimum at pH 5·2). The isolate was a strictly anaerobic chemolithoautotroph capable of using molecular hydrogen as sole energy source and carbon dioxide as sole carbon source. Elemental sulfur served as the sole electron acceptor to support growth. The G+C content of the genomic DNA was 34·0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate was related to members of the generaNautiliaandCaminibacter, although it appeared to be a novel lineage prior to the divergence betweenNautiliaandCaminibacter. Strain Pd55Tcould also be differentiated fromNautiliaandCaminibacterspecies on the basis of its physiological properties. It is, therefore, proposed that strain Pd55T(=JCM 12420T=DSM 16356T) represents the type strain of a novel species in a new genus,Lebetimonas acidiphilagen. nov., sp. nov.

A novel mesophilic sulfur- and thiosulfate-oxidizing bacterium, strain 42BKTT, was isolated from the gas-bubbling sediment at the Iheya North hydrothermal system in the mid-Okinawa Trough, Japan. The isolate was a Gram-negative, non-motile and coccoid to oval-shaped bacterium. Growth was observed at 10–40 °C (optimum 28–30 °C) and in the pH range 5·0–9·0 (optimum 6·5–7·0). Strain 42BKTT grew chemolithoautotrophically with elemental sulfur or thiosulfate as a sole electron donor and oxygen (optimum 5 % in gas phase) or nitrate as an electron acceptor. The G+C content of the genomic DNA was 48·0 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the isolate belonged to the previously uncultivated Group F within the ε-Proteobacteria, which includes phylotypes of vent epibiont and environmental sequences from global deep-sea cold seep and hydrothermal vent fields. On the basis of the physiological and molecular characteristics of this isolate, the type species of a novel genus, Sulfurovum lithotrophicum gen. nov., sp. nov., is proposed. The type strain is 42BKTT (=ATCC BAA-797T=JCM 12117T).

A novel extremely thermophilic, methane-producing archaeon was isolated from a black smoker chimney at the Kairei field in the Central Indian Ridge. Cells of this isolate were irregular cocci with several flagella; motility was not observed. Growth was observed between 55 and 83 °C (optimum of 75 °C; 30 min doubling time) and between pH 6·0 and 8·5 (optimum of pH 6·7). The isolate was a strictly anaerobic, methanogenic autotroph capable of using hydrogen and carbon dioxide as sole energy and carbon sources. Formate was utilized as an alternative energy source. The G+C content of the genomic DNA was 33·3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate was most closely related to Methanotorris igneus strain Kol 5T. The isolate, however, could be genetically differentiated from this species by DNA–DNA hybridization analysis and on the basis of its physiological properties. The name Methanotorris formicicus sp. nov. is proposed for this isolate; the type strain is Mc-S-70T (=JCM 11930T=ATCC BAA-687T).

A novel thermophilic bacterium, strain EP1-55-1%T, was isolated from an in-situ colonization system deployed in a superheated, deep-sea, hydrothermal vent emission at the Kairei Field on the Central Indian Ridge in the Indian Ocean. The cells were highly motile rods, each possessing a single polar flagellum. Growth was observed between 35 and 65 °C (optimum temperature, 55 °C; 70 min doubling time) and between pH 4·9 and 7·2 (optimum, pH 5·9). The isolate was a microaerobic-to-anaerobic chemolithoautotroph capable of using molecular hydrogen as the sole energy source and carbon dioxide as the sole carbon source. Molecular oxygen, nitrate or elemental sulfur (S0) could serve as electron acceptors to support growth. The G+C content of the genomic DNA was 34·6 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that strain EP1-55-1%T represents the first strain for which taxonomic properties have been characterized within the previously uncultivated phylogroup classified as belonging to the uncultivated ε-Proteobacteria group A; the name Hydrogenimonas thermophila gen. nov., sp. nov. is proposed, with strain EP1-55-1%T (=JCM 11971T=ATCC BAA-737T) as the type strain.

A novel mesophilic, sulfur- and thiosulfate-oxidizing bacterium, strain OK10(T), was isolated from deep-sea sediments at the Hatoma Knoll in the Mid-Okinawa Trough hydrothermal field. Cells of strain OK10(T) were short rods, each being motile by means of a single polar flagellum. The isolate grew at 10-40 degrees C (optimum 25 degrees C) and pH 4.5-9.0 (optimum pH 6.5). It grew chemolithoautotrophically with elemental sulfur, sulfide and thiosulfate as sole electron donors and oxygen as electron acceptor. Molecular hydrogen did not support growth. The G+C content of the genomic DNA of strain OK10(T) was 35.2 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, indicated that the isolate belonged to the epsilon-Proteobacteria. On the basis of its physiological and molecular characteristics, strain OK10(T) (=ATCC BAA-671(T)=JCM 11897(T)) represents the sole species of a new genus, Sulfurimonas, for which the name Sulfurimonas autotrophica is proposed.

Summary: A marine bacteriophage active against the marine luminous bacterium Vibrio fischeri MJ-1 was isolated from offshore waters in Ensenada, Baja California, Mexico, and was shown to be active in generalized transduction, transducing 14 of 17 different amino acid auxotrophs to prototrophy. For some of the amino acid auxotrophic markers, such as arginine and methionine, several different mutants could be transduced. The phage grew well at temperatures up to 27 °C, and produced high-titre lysates (1010 p.f.u. ml-1 or higher). Single-step growth analysis showed a latent period of 23 min at 25 °C with a burst size of 100. Phage adsorption was maximum at NaCl concentrations characteristic of the marine environment. No evidence for lysogeny was found.

The names Photobacterium logei Bang et al., Beneckea nereida Baumann et al., and Beneckea gazogenes Harwood were not included in the recently published Approved Lists of Bacterial Names and hence have no standing in bacteriological nomenclature. However, these names are here revived for the same organisms with which they were originally associated and, by this action, now have valid status. According to the current rules of nomenclature, the authors of this present proposal, not the original authors, are to be cited as the authors of these names.

SUMMARY: Parameters of cellular energetics (ATP pools, adenylate energy charge, GTP pools and oxygen consumption) as well as bioluminescence and growth have been examined in batch cultures of four different species of luminous bacteria. The findings indicate that all of these energetic parameters remain constant throughout the growth cycle while bioluminescence is induced and increases many fold. These observations hold true for very bright strains during their dim and bright phases of growth, as well as for a luminescence-conditional strain under bright or dark conditions. The percentage of the total oxygen consumption that was due to bioluminescence was shown to vary by as much as a factor of 103 during growth. For very bright cells, the oxygen consumption experiments suggest both that the energetic requirements of the bioluminescent system are significant, and that the quantum efficiency (Q o2 ) of the luciferase in vivo is quite high, possibly approaching 1·0. Similar considerations based on ATP pool size and energetic estimates of luminescence indicate that the luminous system in bright cells represents a small but possibly significant energy drain. Finally, two methodological features are discussed. First, it was shown that extracts of cells that have been grown in media devoid of inorganic phosphate contain a heat-stable ATPase activity, which can lead to falsely low ATP values. Second, it was shown that the interfering effect of GTP on the assay of ATP could be completely overcome by the addition of GDP to the assay mixture.