Reinekea blandensis sp. nov., a marine, genome-sequenced gammaproteobacterium

Marinicellulosiphila megalodicopiae gen. nov., sp. nov., a deep-sea alkaliphilic cellulolytic bacterium isolated from an endemic ascidian Megalodicopia hians

The strain TOYAMA8T is a deep-sea alkaliphilic cellulolytic bacterium isolated from a slurry-adhered epiphytic site of Megalodicopia hians. Cells of this strain are Gram-negative, aerobic, curved rods or spirilla, motile with monopolar flagella, and grow on cellulose as the sole carbon source. Compared to other closely related species, this bacterium is characterized by a large number of cellulase genes. Strain TOYAMA8T showed alkaliphilic growth within the pH range 7.5-9.0. The major cellular fatty acids were C18 : 1 ω7, C14 : 0, C16 : 0 and C16 : 1 ω7. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipids and aminolipids. A major respiratory lipoquinone was Q-9. Phylogenomic analysis using the 16S rRNA gene and whole-genome sequence data showed that the strain is related to the families Gynuellaceae, Saccharospirillaceae and Natronospirillaceae. The values of 16S rRNA gene sequence similarity, amino acid identity and percentage of conserved proteins between the strain TOYAMA8T and related species were low, with maximum values of 90.6, 48.1 and 34.6%, respectively. These results, together with differences in phenotypic and biochemical characteristics, indicate that the new isolate TOYAMA8T represents a novel genus and species, for which the name Marinicellulosiphila megalodicopiae gen. nov., sp. nov., is proposed. The type strain is TOYAMA8T (JCM 31119T=DSM 114864T).

Reinekea thalattae sp. nov., a New Species of the Genus Reinekea Isolated from Surface Seawater in Sehwa Beach

A Gram-stain-negative, non-pigmented, curved rod-shaped, single polarly flagellated, facultatively anaerobic bacterium, designated as SSH23^T, was isolated from surface seawater sample collected at the Sehwa Beach in South Korea. The novel isolate required NaCl for growth and grew optimally between 2 and 3% NaCl. Strain SSH23^T showed high 16S rRNA gene sequence similarities with Reinekea marinisedimentorum DSM 15388^T (96.4%), Reinekea marina KACC 17315^T (96.2%), Reinekea blandensis KACC 17315^T (95.9%) and Reinekea aestuarii KCTC 22813^T (95.6%). The major polar lipids of strain SSH23^T were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The major cellular fatty acids of strain SSH23^T were C_16:0, summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). The predominant respiratory quinone was found to be ubiquinone-8. The average nucleotide identity values of strain SSH23^T with R. marinisedimentorum DSM 15388^T and R. blandensis MED297^T were determined to be 72.2% and 69.8%, respectively. The G+C content of the genomic DNA was 45.5 mol%. Based on genotypic, phenotypic, chemotaxonomic, and phylogenetic analyses, strain SSH23^T was considered to represent a novel member of the genus Reinekea, for which the name Reinekea thalattae sp. nov. is proposed. The type strain of Reinekea thalattae is SSH23^T (= KACC 21168^T = NBRC 113795^T).

Marinomonas blandensis sp. nov., a novel marine gammaproteobacterium

A novel Gram-staining-negative, chemoorganotrophic, moderately halophilic, strictly aerobic bacterium, strain MED121T, was isolated from a seawater sample collected at the Blanes Bay Microbial Observatory in the north-western Mediterranean Sea. Analysis of its 16S rRNA gene sequence, retrieved from the whole-genome sequence, showed that this bacterium was most closely related to Marinomonas dokdonensis and other Marinomonas species (96.3 and 93.3-95.7 % sequence similarities, respectively), within the family Oceanospirillaceae. Strain MED121T was included into a whole-genome sequencing study and, subsequently, it was characterized using a polyphasic taxonomic approach. It was found to be oxidase and catalase positive, its cells are cocci to short rods, it does not ferment carbohydrates and does not reduce nitrate to nitrite or gas and it requires at least 2.5 % (w/v) marine salts and tolerates up to 7 % (w/v) salts. Its major cellular fatty acids in order of abundance are C16 : 1ω7c/C16 : 1ω6c, C18 : 1ω7c, C16 : 0 and C10 : 0 3-OH. Its genome had an approximate length of 5.1 million bases and a DNA G+C content equal to 40.9 mol%. Analysis of the annotated genes reveals the capacity for the synthesis of ubiquinone 8 (Q8) and the polar lipids phosphatidylglycerol and phosphatidylethanolamine, in agreement with other members of the genus. All the data collected supported the creation of a novel species to accommodate this bacterium, for which the name Marinomonas blandensis sp. nov. is proposed. The type strain is MED121T (=CECT 7076T=LMG 29722T).

Reinekea marina sp. nov., isolated from seawater, and emended description of the genus Reinekea

A Gram-stain-negative, curved rod-shaped and non-pigmented strain, HME8277T, was isolated from surface seawater of the Yellow Sea in the Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel strain was related most closely to Reinekea blandensis MED297T (96.4 % 16S rRNA gene sequence similarity), Reinekea aestuarii IMCC4489T (96.3 %) and Reinekea marinisedimentorum KMM 3655T (95.8 %). The major fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c; 43.0 %), C16 : 0 (19.0 %) and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c; 15.0 %). The DNA G+C content was 46.1 mol%. The predominant respiratory quinone was Q-8. The major polar lipids of strain HME8277T comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, four unidentified phospholipids and four unidentified lipids. On the basis of polyphasic analyses, strain HME8277T represents a novel species of the genus Reinekea, for which the name Reinekea marina sp. nov. is proposed. The type strain HME8277T ( = KACC 17315T = CECT 8288T). An emended description of the genus Reinekea is also provided.

Gynuella sunshinyii gen. nov., sp. nov., an antifungal rhizobacterium isolated from a halophyte, Carex scabrifolia Steud

An antifungal bacterial strain, designated YC6258(T), was isolated from the rhizosphere of a halophyte (Carex scabrifolia Steud.) growing in a tidal flat area of Namhae Island, Korea. Cells of the strain were Gram-stain-negative, facultatively anaerobic, moderately halophilic, rod-shaped and motile by a single polar flagellum. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YC6258(T) formed a phyletic lineage distinct from members of the most closely related genera, Saccharospirillum and Reinekea, with less than 91.2 % sequence similarities. The major cellular fatty acids were C18 : 1ω7c, C16 : 0 and Summed feature 3 (C16 : 1ω7c/ C16 : 1ω6c). The quinone system of strain YC6258(T) consisted mainly of ubiquinone Q-8. The polar lipid profile exhibited phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and unknown lipids. The DNA G+C content was 48.9 mol%. Based on the phylogenetic and phenotypic characteristics, strain YC6258(T) should be classified as a representative of a novel species in a novel genus for which the name Gynuella sunshinyii gen. nov., sp. nov. is proposed. The type strain is YC6258(T) (KCCM 43015(T) = NBRC 109345(T)).

Salinispirillum marinum gen. nov., sp. nov., a haloalkaliphilic bacterium in the family ‘Saccharospirillaceae’

A novel Gram-staining-negative, motile, non-pigmented, facultatively anaerobic, spirillum-shaped, halophilic and alkaliphilic bacterium, designated strain GCWy1T, was isolated from water of the coastal–marine wetland Gomishan in Iran. The strain was able to grow at NaCl concentrations of 1–10 % (w/v) and optimal growth was achieved at 3 % (w/v). The optimum pH and temperature for growth were pH 8.5 and 30 °C, while the strain was able to grow at pH 7.5–10 and 4–40 °C. Phylogenetic analysis based on the comparison of the 16S rRNA gene sequence placed the isolate within the class Gammaproteobacteria as a separate deep branch, with 92.1 % or lower sequence similarity to representatives of the genera Saccharospirillum and Reinekea and less than 91.0 % sequence similarity with other remotely related genera. The major cellular fatty acids of the isolate were C18 : 1ω7c, C16 : 0 and C17 : 0, and the major components of its polar lipid profile were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The cells of strain GCWy1T contained the isoprenoid quinones Q-9 and Q-8 (81 % and 2 %, respectively). The G+C content of the genomic DNA of this strain was 52.3 mol%. On the basis of 16S rRNA gene sequence analysis in combination with chemotaxonomic and phenotypic data, strain GCWy1T represents a novel species in a new genus in the family ‘ Saccharospirillaceae ’, order Oceanospirillales , for which the name Salinispirillum marinum gen. nov., sp. nov. is proposed. The type strain of the type species is GCWy1T ( = IBRC-M 10765T = CECT 8342T).

The phylogenetic and ecological context of cultured and whole genome-sequenced planktonic bacteria from the coastal NW Mediterranean Sea

Microbial isolates are useful models for physiological and ecological studies and can also be used to reassemble genomes from metagenomic analyses. However, the phylogenetic diversity that can be found among cultured marine bacteria may vary significantly depending on the isolation. Therefore, this study describes a set of 136 bacterial isolates obtained by traditional isolation techniques from the Blanes Bay Microbial Observatory, of which seven strains have had the whole genome sequenced. The complete set was compared to a series of environmental sequences obtained by culture-independent techniques (60 DGGE sequences and 303 clone library sequences) previously obtained by molecular methods. In this way, each isolate was placed in both its "ecological" (time of year, nutrient limitation, chlorophyll and temperature values) context or setting, and its "phylogenetic" landscape (i.e. similar organisms that were found by culture-independent techniques, when they were relevant, and when they appeared). Nearly all isolates belonged to the Gammaproteobacteria, Alphaproteobacteria, or the Bacteroidetes (70, 40 and 20 isolates, respectively). Rarefaction analyses showed similar diversity patterns for sequences from isolates and molecular approaches, except for Alphaproteobacteria where cultivation retrieved a higher diversity per unit effort. Approximately 30% of the environmental clones and isolates formed microdiversity clusters constrained at 99% 16S rRNA gene sequence identity, but the pattern was different in Bacteroidetes (less microdiversity) than in the other main groups. Seventeen cases (12.5%) of nearly complete (98-100%) rRNA sequence identity between isolates and environmental sequences were found: nine in the Alphaproteobacteria, five in the Gammaproteobacteria, and three in the Bacteroidetes, indicating that cultivation could be used to obtain at least some organisms representative of the various taxa detected by molecular methods. Collectively, these results illustrated the largely unexplored potential of culturing on standard media for complementing the study of microbial diversity by culture-independent techniques and for obtaining phylogenetically distinct model organisms from natural seawater.

Structural basis for the broad specificity of a new family of amino-acid racemases

Broad-spectrum amino-acid racemases (Bsrs) enable bacteria to generate noncanonical D-amino acids, the roles of which in microbial physiology, including the modulation of cell-wall structure and the dissolution of biofilms, are just beginning to be appreciated. Here, extensive crystallographic, mutational, biochemical and bioinformatic studies were used to define the molecular features of the racemase BsrV that enable this enzyme to accommodate more diverse substrates than the related PLP-dependent alanine racemases. Conserved residues were identified that distinguish BsrV and a newly defined family of broad-spectrum racemases from alanine racemases, and these residues were found to be key mediators of the multispecificity of BrsV. Finally, the structural analysis of an additional Bsr that was identified in the bioinformatic analysis confirmed that the distinguishing features of BrsV are conserved among Bsr family members.

Reinekea aestuarii sp. nov., isolated from tidal flat sediment

Two Gram-negative, non-motile, non-pigmented and curved rod-shaped bacterial strains, designated IMCC4489T and IMCC4451, were isolated from a tidal flat sediment of the Yellow Sea. Strains IMCC4489T and IMCC4451 shared 99.9 % 16S rRNA gene sequence similarity and 78.5 % DNA–DNA relatedness, which suggested that they belonged to the same species. The isolates were most closely related to Reinekea blandensis MED297T (98.7–98.8 % 16S rRNA gene sequence similarity) and Reinekea marinisedimentorum DSM 15388T (95.3–95.4 %). DNA–DNA relatedness between the strains and R. blandensis CCUG 52066T was 31–34 %. Strains IMCC4489T and IMCC4451 could also be differentiated from the type strains of the two recognized Reinekea species by several phenotypic properties. The DNA G+C content was 51.3–51.5 mol% and the major isoprenoid quinone was Q-8. On the basis of the data obtained in this study, it is proposed that strains IMCC4489T and IMCC4451 represent a novel species, Reinekea aestuarii sp. nov. The type strain is IMCC4489T (=KCTC 22813T =KCCM 42938T =NBRC 106079T).

Legionella pneumophila secretes an endoglucanase that belongs to the family-5 of glycosyl hydrolases and is dependent upon type II secretion

Examination of cell-free culture supernatants revealed that Legionella pneumophila strains secrete an endoglucanase activity. Legionella pneumophila lspF mutants were deficient for this activity, indicating that the endoglucanase is secreted by the bacterium's type II protein secretion (T2S) system. Inactivation of celA, encoding a member of the family-5 of glycosyl hydrolases, abolished the endoglucanase activity in L. pneumophila culture supernatants. The cloned celA gene conferred activity upon recombinant Escherichia coli. Thus, CelA is the major secreted endoglucanase of L. pneumophila. Mutants inactivated for celA grew normally in protozoa and macrophage, indicating that CelA is not required for the intracellular phase of L. pneumophila. The CelA endoglucanase is one of at least 25 proteins secreted by the type II system of L. pneumophila and the 17th type of enzyme effector associated with this pathway. Only a subset of the other Legionella species tested expressed secreted endoglucanase activity, suggesting that the T2S output differs among the different legionellae. Overall, this study represents the first documentation of an endoglucanase (EC 3.2.1.4) being produced by a strain of Legionella.

Bermanella marisrubri gen. nov., sp. nov., a genome-sequenced gammaproteobacterium from the Red Sea

A novel heterotrophic, marine, strictly aerobic, motile bacterium was isolated from the Red Sea at a depth of 1 m. Analysis of its 16S rRNA gene sequence, retrieved from the whole-genome sequence, showed that this bacterium was most closely related to the genera Oleispira, Oceanobacter and Thalassolituus, each of which contains a single species, within the class Gammaproteobacteria. Phenotypic, genotypic and phylogenetic analyses supported the creation of a novel genus and species to accommodate this bacterium, for which the name Bermanella marisrubri gen. nov., sp. nov. is proposed. The type strain of Bermanella marisrubri is RED65(T) (=CECT 7074(T) =CCUG 52064(T)).