Prototheca tumulicola sp. nov., a novel achlorophyllous,yeast-like microalga isolated from the stone chamber interior of the Takamatsuzuka Tumulus

Two achlorophyllous microalgal strains were isolated from the soil and white moldy colony collected inside the stone chamber of the Takamatsuzuka Tumulus in Japan. Phylogenetic analyses of the small subunit ribosomal RNA (SSU rRNA) and Dl/D2 large subunit ribosomal RNA (LSU rRNA) gene sequences, and concatenated gene sequences of the SSU and D1/D2 LSU rRNA genes indicated that our two isolates were the members of the non-photosynthetic, yeast-like microalgal Chlorellaceous genus Prototheca (Chlorellales, Trebouxiophyceae, Chlorophyta) but well distinguished from known species. Based on phenotypic and genotypic characteristics, isolates T6713-13-10^T and T61213-7-11 are proposed to represent a novel species in Prototheca, P. tumulicola, with the type strain JCM 31123^T (isolate T6713-13-10^T).     

Flavobacterium aquaticum sp. nov., a member of the Bacteroidetes isolated from a freshwater reservoir

A novel bacterial strain, designated ARSA-111^T, was isolated from a freshwater reservoir in Cheonan, Korea. Phylogenetic analysis based on 16S rRNA gene sequences suggested that the isolate belonged to the genus Flavobacterium of phylum Bacteroidetes. The 16S rRNA gene sequence of strain ARSA-111^T showed a high degree of sequence similarity to those of Flavobacteium cheonanense KACC 14972^T (97.3%), F. aquatile JCM 20475^T (97.1%), and other type strains of the genus Flavobacterium (< 97.0%). The phylogenetic tree and network analysis (i.e. median-joining) based on 16S rRNA gene sequences showed that strain ARSA-111^T is most closely related to F. aquatile JCM 20475^T. DNA-DNA hybridization experiment revealed 70% of genomic relatedness among strain ARSA-111^T, F. aquatile JCM 20475^T and F. cheonanense KACC 14972^T. The isolate had iso-C_15:1, iso-C_15:0, and iso-C_15:0 3-OH as predominant cellular fatty acids and MK-6 as a predominant menaquinone. The genomic DNA G+C content of the isolate was 35.6 mol%. On the basis of these data, strain ARSA-111^T is considered to be a novel species of the genus Flavobacterium, for which the name Flavobacterium aquaticum sp. nov. is proposed. The type strain is strain ARSA-111^T (=KACC 14973^T =KCTC 23185^T = JCM 17070^T).     

Halorubrum halophilum sp. nov., an extremely halophilic archaeon isolated from a salt-fermented seafood

A novel, red-pigmented, pleomorphic and short rod-shaped haloarchaeon, designated B8^T, was isolated from a salt-fermented seafood. Strain B8^T was found to be able to grow at 20–45 °C, in the presence of 15–30 % (w/v) NaCl and at pH 7.0–9.0. The optimum requirements were found to be a temperature range of 35–40 °C, pH 8.0 and the presence of 25 % NaCl. The cells of strain B8^T were observed to be Gram-staining negative and lysed in distilled water. Anaerobic growth did not occur in the presence of nitrate, l-arginine, dimethyl sulfoxide or trimethylamine N-oxide. The catalase and oxidase activities were found to be positive and nitrate was reduced in aerobic conditions. Tween 20, 40 and 80 were found to be hydrolyzed, whereas casein, gelatin and starch were not hydrolyzed. Indole or H₂S was not formed and urease activity was not detected. A phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain B8^T is most closely related to members of the genus Halorubrum in the family Halobacteriaceae. Strain B8^T was found to have three 16S rRNA genes, rrnA, rrnB and rrnC; similarities between the 16S rRNA gene sequences are 99.0–99.8 %. Strain B8^T shared 99.0 % 16S rRNA gene sequence similarity with Halorubrum (Hrr.) lipolyticum JCM 13559^T and Hrr. saccharovorum DSM 1137^T, 98.8 % with Hrr. kocurii JCM 14978^T, 98.3 % with Hrr. lacusprofundi DSM 5036^T, 98.0 % with Hrr. arcis JCM 13916^T, 97.7 % with Hrr. aidingense JCM 13560^T and 97.0 % with Hrr. aquaticum JCM 14031^T, as well as 93.7–96.5 % with other type strains in the genus Halorubrum. The RNA polymerase subunit B′ gene sequence similarity of strain B8^T with Hrr. kocurii JCM 14978^T is 97.2 % and lower with other members of the genus Halorubrum. DNA–DNA hybridization experiments showed that strain B8^T shared equal or lower than 50 % relatedness with reference species in the genus Halorubrum. The genomic DNA G+C content of strain B8^T was determined to be 64.6 mol%. The major isoprenoid quinone of strain B8^T was identified as menaquinone-8 and the major polar lipids as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, sulfated mannosyl glucosyl diether and an unidentified phospholipid. Based on this polyphasic taxonomic study, strain B8^T is considered to represent a new species in the genus Halorubrum, for which the name Hrr. halophilum sp. nov. is proposed. The type strain is B8^T (=JCM 18963^T = CECT 8278^T).     

Description of the two novel species of the genus Helicobacter: Helicobacter anatolicus sp. nov., and Helicobacter kayseriensis sp. nov., isolated from feces of urban wild birds

A total of 26 Gram-negative, motile, gently curved, and rod-shaped isolates were recovered, during a study to determine the faeco-prevalence of Helicobacter spp. in urban wild birds. Pairwise comparisons of the 16S rRNA gene sequences indicated that these isolates belonged to the genus Helicobacter and phylogenetic analysis based on the 16S rRNA gene sequences showed that the isolates were separated into two divergent groups. The first group consisted of 20 urease-positive isolates sharing the highest 16S rRNA gene sequence identity levels of 98.5–98.6% to H. mustelae ATCC 43772^T, while the second group contained six urease-negative isolates with the sequence identity level of 98.5% to the type strain of H. pametensis ATCC 51478^T. Five isolates were chosen and subjected to comparative whole-genome analysis. The phylogenetic analysis of the 16S rRNA, gyrA and atpA gene sequences showed that Helicobacter isolates formed two separate phylogenetic clades, differentiating the isolates from the other Helicobacter species. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) analyses between strains faydin-H8^T, faydin-H23^T and their close neighbors H. anseris MIT 04-9362^T and H. pametensis ATCC 51478^T, respectively, confirmed that both strains represent novel species in the genus Helicobacter. The DNA G+C contents of the strains faydin-H8^T and faydin-H23^T are 32.0% and 37.6%, respectively. The results obtained for the characterization of the wild bird isolates indicate that they represent two novel species, for which the names Helicobacter anatolicus sp. nov., and Helicobacter kayseriensis sp. nov., are proposed, with faydin-H8^T(=LMG 32237^T = DSM 112312^T) and faydin-H23^T(=LMG 32236^T = CECT 30508^T) as respective type strains.     

Arcobacter ellisii sp. nov., isolated from mussels

As part of a study carried out for detecting Arcobacter spp. in shellfish, three mussel isolates that were Gram-negative slightly curved rods, non-spore forming, showed a new 16S rDNA-RFLP pattern with a specific identification method for the species of this genus. Sequences of the 16S rRNA gene and those of the housekeeping genes rpoB, gyrB and hsp60 provided evidence that these mussel strains belonged to an unknown genetic lineage within the genus Arcobacter. The similarity between the 16S rRNA gene sequence of the representative strain (F79-6^T) and type strains of the other Arcobacter species ranged between 94.1% with A. halophilus and 99.1% with the recently proposed species A. defluvii (CECT 7697^T). DDH results between strain F79-6^T and the type strain of the latter species were below 70% (53 ± 3.0%). Phenotypic characteristics together with MALDITOF mass spectra differentiated the new mussel strains from all other Arcobacter species. All the results indicate that these strains represent a new species, for which the name Arcobacter ellisii sp. nov. with the type strain F79-6^T (=CECT 7837^T = LMG 26155^T) is proposed.     

Desulfovibrio oceani subsp. oceani sp. nov., subsp. nov. and Desulfovibrio oceani subsp. galateae subsp. nov., novel sulfate-reducing bacteria isolated from the oxygen minimum zone off the coast of Peru

Two deltaproteobacterial sulfate reducers, designated strain I.8.1^T and I.9.1^T, were isolated from the oxygen minimum zone water column off the coast of Peru at 400 and 500 m water depth. The strains were Gram-negative, vibrio-shaped and motile. Both strains were psychrotolerant, grew optimally at 20°C at pH 7.0–8.0 and at 2.5–3.5% NaCl (w/v). The strains grew by utilizing hydrogen/acetate, C_3–4 fatty acids, amino acids and glycerol as electron acceptors for sulfate reduction. Fumarate, lactate and pyruvate supported fermentative growth. Sulfate, sulfite, thiosulfate and taurin supported growth as electron acceptors. Both strains were catalase-positive and highly oxygen-tolerant, surviving 24 days of exposure to atmospheric concentrations. MK6 was the only respiratory quinone. The most prominent cellular fatty acid was iso-17:1-ω9c (18%) for strain I.8.1^T and iso-17:0-ω9c (14%) for strain I.9.1^T. The G+C contents of their genomic DNA were 45–46 mol%. Phylogenetic analysis of 16S rRNA and dsrAB gene sequences showed that both strains belong to the genus Desulfovibrio. Desulfovibrio acrylicus DSM 10141^T and Desulfovibrio marinisediminis JCM 14577^T represented their closest validly described relatives with pairwise 16S rRNA gene sequence identities of 98–99%. The level of DNA-DNA hybridization between strains I.8.1^T and I.9.1^T was 30–38%. The two strains shared 10–26% DNA-DNA relatedness with D. acrylicus. Based on a polyphasic investigation it is proposed that strains I.8.1^T and I.9.1^T represent a novel species for which the name Desulfovibrio oceani sp. nov. is proposed with the two subspecies D. oceani subsp. oceani (type strain, I.8.1^T = DSM 21390^T = JCM 15970^T) and D. oceani subsp. galateae (type strain, I.9.1^T = DSM 21391^T = JCM 15971^T).     

Algivirga pacifica gen. nov., sp. nov., a Novel Agar-Degrading Marine Bacterium of the Family Flammeovirgaceae Isolated from Micronesia

An aerobic, Gram-negative, coccoid to short rod-shaped and non-flagellated marine bacterial strain S354^T was isolated from seawater of Micronesia. The strain was capable to degrade agar-forming slight depression into agar plate. Growth occurred at a temperature range of 12–44 °C, a pH range of 5–9, and a salinity range of 1–7 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences suggested that S354^T belongs to the family Flammeovirgaceae. The novel strain was most closely related to Limibacter armeniacum YM 11-185^T with similarity of 92.5 %. The DNA G+C content was 43.8 mol%. The major fatty acids (>10 %) were iso-C_15:0 and C_16:1 ω5c. The predominant isoprenoid quinone was determined to be MK-7. Polar lipid profile of S354^T consisted of phosphatidylethanolamine, unknown polar lipid, and unknown glycolipids. Based on the phenotypic, phylogenetic, biochemical, and physiological tests conducted in this study, S354^T is proposed to represent a type strain of a novel genus and species. The 16S rRNA gene sequence of S354^T is registered in GenBank under the accession number JQ639084. The type of strain Algivirga pacifica gen. nov., sp. nov. is S354^T (=KCCM 90107^T=JCM 18326^T).     

Arcobacter molluscorum sp. nov., a new species isolated from shellfish

Nineteen bacteria isolates recovered from shellfish samples (mussels and oysters) showed a new and specific 16S rDNA-RFLP pattern with an Arcobacter identification method designed to recognize all species described up to 2008. These results suggested that they could belong to a new species. ERIC-PCR revealed that the 19 isolates belonged to 3 different strains. The sequence of the 16S rRNA gene of a representative strain (F98-3^T) showed 97.6% similarity with the closest species Arcobacter marinus followed by Arcobacter halophilus (95.6%) and Arcobacter mytili (94.7%). The phylogenetic analysis with the16S rRNA, rpoB, gyrB and hsp60 genes placed the shellfish strains within the same cluster as the three species mentioned (also isolated from saline habitats) but they formed an independent phylogenetic line. The DDH results between strain F98-3^T and A. marinus (54.8% ± 1.05), confirmed that it represents a new species. Several biochemical tests differentiated the shellfish isolates from all other Arcobacter species. Although the new species was different from A. mytili, they shared not only the same habitat (mussels) but also the characteristic of being so far the only Arcobacter species that are simultaneously negative for urea and indoxyl acetate hydrolysis. All results supported the classification of the shellfish strains as a new species, for which the name Arcobacter molluscorum sp. nov. with the type strain F98-3^T is proposed (=CECT 7696^T = LMG 25693^T).     

Paenibacillus pinihumi sp. nov., a cellulolytic bacterium isolated from the rhizosphere of Pinus densiflora

A novel cellulolytic bacterium, strain S23^T, was isolated from the rhizosphere of the pine trees in Daejeon, Republic of Korea. This isolate was Gram-positive, strictly aerobic, rod-shaped, catalase-negative, oxidase-positive, motile by means of peritrichous flagella, and tested positive for alkaline phosphatase, esterase lipase, leucine arylamidase, α-galactosidase, and β-galactosidase activities. The DNA G+C content was 49.5 mol%. The main cellular fatty acids were anteiso-C_15:0 (51.9%), iso-C_16:0 (14.7%), and iso-C_15:0 (13.2%). The major isoprenoid quinone was menaquinone 7 (MK-7). Diagnostic diamino acid in the cell-wall pepti-doglycan was meso-diaminopimelic acid. Comparative 16S rRNA gene sequence analysis showed that this strain clustered with Paenibacillus species. The 16S rRNA gene sequence similarity values between S23^T and other Paenibacillus species were between 89.9% and 95.9%, and S23^T was most closely related to Paenibacillus tarimensis SA-7-6^T. On the basis of phylogenetic and phenotypic properties of strain S23^T, the isolate is considered as a novel species belonging to the genus Paenibacillus. Therefore, the name, Paenibacillus pinihumi sp. nov., is proposed for the rhizosphere isolate; the type strain is S23^T (=KCTC 13695^T =KACC 14199^T =JCM 16419^T)     

Streptacidiphilus hamsterleyensis sp. nov., isolated from a spruce forest soil

Three acidophilic actinobacteria, isolates LSCA2, FGG8 and HSCA14^T, recovered from spruce litter were examined using a polyphasic approach. Chemotaxonomic and morphological properties of the isolates were found to be consistent with their classification in the genus Streptacidiphilus. The isolates were shown to have identical 16S rRNA gene sequences and were most closely related to Streptacidiphilus neutrinimicus DSM 41755^T (99.9 % similarity). However, DNA:DNA relatedness between isolate HSCA14^T and the type strain of S. neutrinimicus was found to be low at 44.0 (±14.1) %. A combination of phenotypic features, including degradative and nutritional characteristics were shown to distinguish the isolates from their nearest phylogenetic neighbours. Data from this study show that the isolates form a novel species in the genus for which the name S. hamsterleyensis sp. nov. is proposed. The type strain is HSCA 14^T (=DSM 45900^T = KACC 17456^T = NCIMB 14865^T).     

<Emphasis Type="Italic">Bacillus ferrooxidans</Emphasis> sp. nov., an iron(II)-oxidizing bacterium isolated from paddy soil

An endospore-forming bacterium, designated YT-3^T, was isolated from a paddy soil in Yingtan, Jiangxi, China. Cells of strain YT-3^T were Gram-positive, rod-shaped, facultative anaerobic, catalase, and oxidase positive. The optimum growth temperature and pH were 30°C (ranged from 15 to 50°C) and 6.5–7.0 (ranged from 3 to 11), respectively. Analysis of the 16S rRNA gene sequence showed that strain YT-3^T was affiliated to the genus Bacillus and displayed the highest similarity to that of Bacillus drentensis JCM 21707^T (98.3%), followed by B. ginsengisoli JCM 17335^T (97.8%) and B. fumarioli JCM 21708^T (97.0%). The similarity of rpoB gene sequence between strain YT-3^T and B. drentensis JCM 21707^T, B. ginsengisoli JCM 17335^T and B. fumarioli JCM 21708T was 80.4%, 81.5%, and 82.1%, respectively. The genomic DNA G + C content was 44.9 mol%. The predominant respiratory quinone was Menaquinone-7, and meso-diaminopimelic acid was present in the peptidoglycan layer of cell wall. The major fatty acids were C_15:0 anteiso (36.2%), C_14:0 iso (19.6%), C_15:0 iso (17.4%), and C_16:0 iso (9.8%). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phospholipids, and ammoniac phospholipids. The DNA-DNA hybridization values between isolate YT-3^T and B. drentensis (JCM 21707^T), B. ginsengisoli (JCM 17335^T), and B. fumarioli (JCM 21708^T) were 36.3%, 30.3%, and 25.3%, respectively. On the basis of physiological, genetic and biochemical data, strain YT-3^T represented a novel species of the genus Bacillus, for which the name Bacillus ferrooxidans sp. nov was proposed. The type strain is YT-3^T (= KCTC 33875T = CCTCC AB 2017049T).     

<Emphasis Type="Italic">Promicromonospora viridis</Emphasis> sp. nov., a novel actinomycete isolated from soil

Two Gram-stain positive, aerobic actinomycete strains, designated NEAU-JGR1^T and NEAU-JGC41, were isolated from soil collected from Fairy Lake Botanical Garden in Shenzhen, Guangdong Province, south of China. The 16S rRNA gene sequences analysis showed that the two strains exhibited 99.5% 16S rRNA gene sequence similarity with each other and were closely related to Promicromonospora thailandica JCM 17130^T (99.4, 99.3%) and Promicromonospora citrea DSM 43110^T (99.2, 99.2%). Phylogenetic analysis based on the 16S rRNA gene sequences indicated that the two strains clustered together and formed a cluster with P. thailandica JCM 17130^T and P. citrea DSM 43110^T. Both strains were observed to contain MK-9(H₄) and MK-9(H₂) as predominant menaquinones. Their whole cell sugar profiles were found to main contained rhamnose, ribose, glucose and galactose. The phospholipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, glycophosphatidylinositol, phosphatidylinositol mannoside, an unidentified glycolipid and an unidentified phospholipid. The predominant cellular fatty acids for the two strains were identified as anteiso-C_15:0, iso-C_15:0 and anteiso-C_17:0. The DNA–DNA hybridization value between strains NEAU-JGR1^T and NEAU-JGC41 was 85.1?±?0.3%, and the values between the two strains and their close phylogenetic relatives were well below 70%, supporting the conclusion that they represent a distinct genomic species. An array of phenotypic characteristics also differentiated the isolates from closely related species. On the basis of the genetic and phenotypic properties, strains NEAU-JGR1^T and NEAU-JGC41 can be classified as representatives of a novel species of the genus Promicromonospora, for which the name Promicromonospora viridis sp. nov., is proposed. The type strain is NEAU-JGR1^T (=?DSM 105536^T?=?CGMCC 4.7473^T).     

Halococcus sediminicola sp. nov., an extremely halophilic archaeon isolated from a marine sediment

A novel, red-pigmented and coccoid haloarchaeon, designated strain CBA1101^T, was isolated from a marine sediment. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CBA1101^T is most closely related to the genus Halococcus in the family Halobacteriaceae. Strain CBA1101^T had a highest 16S rRNA gene sequence similarity of 98.4 % with Halococcus dombrowskii DSM 14522^T, followed by 93.7–98.3 % with sequences of other type strains in the genus Halococcus. The RNA polymerase subunit B′ gene sequence similarity of strain CBA1101^T with that of Halococcus qingdaonensis JCM 13587^T is 89.5 % and lower with those of other members of the genus Halococcus. Strain CBA1101^T was observed to grow at 25–40 °C, pH 6.0–9.0 and in the presence of 15–30 % (w/v) NaCl, with optimal growth at 35–40 °C, pH 7.0 and with 20 % NaCl. The cells of strain CBA1101^T are Gram-negative and did not lyse in distilled water. The major polar lipids were identified as phosphatidylglyerol, phosphatidylglycerol phosphate methyl ester, sulfated diglycosyl diether, unidentified phospholipids and unidentified glycolipids. The genomic DNA G+C content was determined 66.0 mol%. The DNA–DNA hybridization experiment showed that there was less than 40 % relatedness between strain CBA1101^T and the reference species in the genus Halococcus. Based on this polyphasic taxonomic analysis, strain CBA1101^T is considered to represent a new species in the genus Halococcus, for which the name Halococcus sediminicola sp. nov. is proposed. The type strain is CBA1101^T (=JCM 18965^T = CECT 8275^T).     

<Emphasis Type="Italic">Halorubrum cibi</Emphasis> sp. nov., an extremely halophilic archaeon from salt-fermented seafood

Strain B31^T is a Gram-staining-negative, motile, and extremely halophilic archaeon that was isolated from salt-fermented seafood. Its morphology, physiology, biochemical features, and 16S rRNA gene sequence were determined. Phylogenetic analysis of its 16S rRNA gene sequence and composition of its major polar lipids placed this archaeon in the genus Halorubrum of the family Halobacteriaceae. Strain B31^T showed 97.3, 97.2, and 96.9 % 16S rRNA similarity to the type strains of Halorubrum alkaliphilum, Hrr. tibetense, and Hrr. vacuolatum, respectively. Its major polar lipids were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me) and sulfated diglycosyl diether (S-DGD). Genomic DNA from strain B31^T has a 61.7 mol% G+C content. Analysis of 16S rRNA gene sequences, as well as physiological and biochemical tests, identified genotypic and phenotypic differences between strain B31^T and other Halorubrum species. The type strain of the novel species is B31^T (=JCM 15757^T =DSM 19504^T).     

Characterization of two novel pentose-fermenting and GABA-producing species: Levilactobacillus tujiorum sp. nov. and Secundilactobacillus angelensis sp. nov. Isolated from a solid-state fermented zha-chili

Lactobacilli are dominant in zha-chili. This study provides a taxonomic characterization of five bacterial strains isolated from zha-chili in China. The cells were Gram-positive, facultative anaerobic, non-spore-forming, flagella-free, catalase-negative, heterofermentative, pentose-fermenting, and gamma-aminobutyric acid (GABA)-producing rods. For HBUAS51241^T, HBUAS51329, and HBUAS51416, C_16:0, C_18:1 ω9c and C_19:0 iso were the predominant cellular fatty acids; diphosphatidylglycerol (DPG), phosphatidylglycerol (DP), glycolipids (GL), and glycolipids (AL) were the major phospholipids. While for HBUAS51383^T and HBUAS58055, C_16:0, C_18:1 ω9c, C_19:0 cyclo ω8c were the predominant cellular fatty acids; DPG, DP, GL, and AL were the major phospholipids. Strains HBUAS51241^T, HBUAS51329, and HBUAS51416 showed 98.1–99.1% 16S rRNA gene sequence similarity, 80.2–81.4% ANI, 87.7–90.0% AAI, and 23.8–32.8% digital DDH to their closest related type strains Levilactobacillus hammesii DSM 16381^T, Levilactobacillus parabrevis ATCC 53295^T, and Levilactobacillus fuyuanensis 244-4^T. Strains HBUAS51383^T and HBUAS58055 showed 98.7–99.5% 16S rRNA gene sequence similarity, 75.4–81.4% ANI, 75.5–89.1% AAI, and 19.7–24.0% digital DDH to their closest related type strains Secundilactobacillus silagincola IWT5^T, Secundilactobacillus silagei JCM 19001^T, Secundilactobacillus pentosiphilus IWT25^T, Secundilactobacillus mixtipabuli IWT30^T, Secundilactobacillus odoratitofui DSM 19909^T, and Secundilactobacillus similis DSM 23365^T. The central carbon metabolism pathways for the five strains were summarizeded. Based on the phenotypic, chemotaxonomic, and genomic data, we propose two novel species Levilactobacillus tujiorum sp. nov. whose type strain is HBUAS51241^T (=GDMCC 1.3022^T = JCM 35241^T), and Secundilactobacillus angelensis sp. nov. whose type strain is HBUAS51383^T (=GDMCC 1.3021^T = JCM 35209^T).     

Advanced Microbial Taxonomy Combined with Genome-Based-Approaches Reveals that Vibrio astriarenae sp. nov., an Agarolytic Marine Bacterium,Forms a New Clade in Vibrionaceae

Advances in genomic microbial taxonomy have opened the way to create a more universal and transparent concept of species but is still in a transitional stage towards becoming a defining robust criteria for describing new microbial species with minimum features obtained using both genome and classical polyphasic taxonomies. Here we performed advanced microbial taxonomies combined with both genome-based and classical approaches for new agarolytic vibrio isolates to describe not only a novel Vibrio species but also a member of a new Vibrio clade. Two novel vibrio strains (Vibrio astriarenae sp. nov. C7^T and C20) showing agarolytic, halophilic and fermentative metabolic activity were isolated from a seawater sample collected in a coral reef in Okinawa. Intraspecific similarities of the isolates were identical in both sequences on the 16S rRNA and pyrH genes, but the closest relatives on the molecular phylogenetic trees on the basis of 16S rRNA and pyrH gene sequences were V. hangzhouensis JCM 15146^T (97.8% similarity) and V. agarivorans CECT 5085^T (97.3% similarity), respectively. Further multilocus sequence analysis (MLSA) on the basis of 8 protein coding genes (ftsZ, gapA, gyrB, mreB, pyrH, recA, rpoA, and topA) obtained by the genome sequences clearly showed the V. astriarenae strain C7^T and C20 formed a distinct new clade protruded next to V. agarivorans CECT 5085^T. The singleton V. agarivorans has never been included in previous MLSA of Vibrionaceae due to the lack of some gene sequences. Now the gene sequences are completed and analysis of 100 taxa in total provided a clear picture describing the association of V. agarivorans into pre-existing concatenated network tree and concluded its relationship to our vibrio strains. Experimental DNA-DNA hybridization (DDH) data showed that the strains C7^T and C20 were conspecific but were separated from all of the other Vibrio species related on the basis of both 16S rRNA and pyrH gene phylogenies (e.g., V. agarivorans CECT 5085^T, V. hangzhouensis JCM 15146^T V. maritimus LMG 25439^T, and V. variabilis LMG 25438^T). In silico DDH data also supported the genomic relationship. The strains C7^T also had less than 95% average amino acid identity (AAI) and average nucleotide identity (ANI) towards V. maritimus C210, V. variabilis C206, and V. mediterranei AK1^T, V. brasiliensis LMG 20546^T, V. orientalis ATCC 33934^T, and V. sinaloensis DSM 21326. The name Vibrio astriarenae sp. nov. is proposed with C7 as the type strains. Both V. agarivorans CECT 5058^T and V. astriarenae C7^T are members of the newest clade of Vibrionaceae named Agarivorans.     

Rhizobium qilianshanense sp. nov., a novel species isolated from root nodule of Oxytropis ochrocephala Bunge in China

During a study of the diversity and phylogeny of rhizobia isolated from root nodules of Oxytropis ochrocephala grown in the northwest of China, four strains were classified in the genus Rhizobium on the basis of their 16S rRNA gene sequences. These strains have identical 16S rRNA gene sequences, which showed a mean similarity of 94.4 % with the most closely related species, Rhizobium oryzae. Analysis of recA and glnA sequences showed that these strains have less than 88.1 and 88.7 % similarity with the defined species of Rhizobium, respectively. The genetic diversity revealed by ERIC-PCR fingerprinting indicated that the isolates correspond to different strains. Strain CCNWQLS01^T contains Q-10 as the predominant ubiquinone. The major fatty acids were identified as feature 8 (C18: 1ω7c and/or C18: 1ω6c; 67.2 %). Therefore, a novel species Rhizobium qilianshanense sp. nov. is proposed, and CCNWQLS01^T (= ACCC 05747^T = JCM 18337^T) is designated as the type strain.     

Halorubrum rubrum sp. nov., an extremely halophilic archaeon from a Chinese salt lake

Two halophilic archaeal strains, YC87^T and YCA11, were isolated from Yuncheng salt lake in Shanxi, China. Cells of the two strains were observed to be pleomorphic rod-shaped, stained Gram-negative and produced red-pigmented colonies. Strain YC87^T was able to grow at 20–50 °C (optimum 37 °C), at 1.4–4.8 M NaCl (optimum 2.1 M NaCl), at 0.05–1.0 M MgCl₂ (optimum 0.3 M MgCl₂) and at pH 6.0–9.0 (optimum pH 7.0) while strain YCA11 was able to grow at 20–50 °C (optimum 37 °C), at 2.1–4.8 M NaCl (optimum 3.1 M NaCl), at 0.01–0.7 M MgCl₂ (optimum 0.1 M MgCl₂) and at pH 6.0–9.0 (optimum pH 7.5). The cells of both isolates were observed to lyse in distilled water. The minimum NaCl concentrations that prevented cell lysis were determined to be 8 % (w/v) for strain YC87^T and 12 % (w/v) for strain YCA11. The major polar lipids of the two strains were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and one major glycolipid chromatographically identical to sulfated mannosyl glucosyl diether; another major glycolipid and trace amounts of several unidentified lipids were also detected. The 16S rRNA gene sequences of the two strains were 99.8 % identical, showing 93.2–98.2 % similarity to members of the genus Halorubrum of the family Halobacteriaceae. The rpoB′ gene similarity between strains YC87^T and YCA11 was 99.3 % and showed 87.5–95.2 % similarity to the closest relative members of the genus Halorubrum. The DNA G+C content of strains YC87^T and YCA11 were determined to be 64.9 and 64.5 mol%, respectively. The DNA–DNA hybridization value between strain YC20^T and strain YC77 was 87 % and the two strains showed low DNA–DNA relatedness with Halorubrum cibi JCM 15757^T and Halorubrum aquaticum CGMCC 1.6377^T, the most related members of the genus Halorubrum. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strains YC87^T and YCA11 represent a novel species of the genus Halorubrum, for which the name Halorubrum rubrum sp. nov. is proposed. The type strain is YC87^T (=CGMCC 1.12124^T = JCM 18365^T).