Description of Pseudoclavibacter triregionum sp. nov. from human blood and Pseudoclavibacter albus comb. nov., and revised classification of the genus Pseudoclavibacter: proposal of Caespitibacter gen. nov., with Caespitibacter soli comb. nov. and Caespitibacter caeni comb. nov

We present polyphasic taxonomic data to demonstrate that strain 125703-2019^T, a human blood isolate, represents a novel species within the genus Pseudoclavibacter, and to reclassify the illegitimate Zimmermannella alba Lin et al., 2004 as Pseudoclavibacter albus comb. nov. Upon primary isolation, strain 125703-2019^T could not be identified reliably using MALDI-TOF mass spectrometry during routine diagnostic work, but partial 16S rRNA gene sequence analysis revealed that it belonged to the genus Pseudoclavibacter. Average nucleotide identity and digital DNA-DNA hybridisation analyses confirmed that it represented a novel species within this genus. A detailed physiological characterisation yielded differential tests between the novel species and its nearest neighbor taxa, which could also be differentiated using MALDI-TOF mass spectrometry. We propose to formally classify this strain into the novel species Pseudoclavibacter triregionum sp. nov., with strain 125703-2019^T (=?R-76471^T, LMG 31777^T, CCUG 74796^T) as the type strain. The whole-genome assembly of strain 125703-2019^T has a size of 2.4 Mb and a G?+?C content of 72.74%. A Pseudoclavibacter pangenome analysis revealed that 667 gene clusters were exclusively present in strain 125703-2019^T. While these gene clusters were enriched in several COG functional categories, this analysis did not reveal functions that explained the occurrence of this species in human infection. Finally, several phylogenetic and phylogenomic analyses demonstrated that the genus Pseudoclavibacter is polyphyletic with Pseudoclavibacter soli and Pseudoclavibacter caeni representing a unique and deeply branching line of descent within the family Microbacteriaceae. We therefore also propose to reclassify both species into the novel genus Caespitibacter gen. nov. as Caespitibacter soli comb. nov. and Caespitibacter caeni comb. nov., respectively, and with C. soli comb. nov. as the type species.

     

Halorussus rarus gen. nov., sp. nov., a new member of the family Halobacteriaceae isolated from a marine solar saltern

Two halophilic archaeal strains TBN4^T and TBN5 were isolated from Taibei marine solar saltern in Jiangsu, China. Both strains showed light red-pigmented colonies and their cells were rod, motile and Gram-stain-negative. They were able to grow at 25–50°C (optimum 37°C), at 1.4–4.3 M NaCl (optimum 2.1 M NaCl), at 0–1.0 M MgCl₂ (optimum 0.005 M MgCl₂) and at pH 6.0–9.0 (optimum pH 7.0). Their cells lyse in distilled water and minimal NaCl concentration to prevent cell lysis is 8% (w/v). The major polar lipids of the two strains were PG (phosphatidylglycerol), PGP-Me (phosphatidylglycerol phosphate methyl ester), PGS (phosphatidylglycerol sulfate) and five glycolipids chromatographically identical to S-TGD-1 (sulfated galactosyl mannosyl glucosyl diether), S-DGD-1 (sulfated mannosyl glucosyl diether), TGD-1 (galactosyl mannosyl glucosyl diether), DGD-1 (mannosyl glucosyl diether) and DGD-2 (an unknown diglycosyl diether). Phylogenetic analysis revealed that TBN4^T and strain TBN5 formed a distinct clade with genus Haladaptatus (showing 90.0–90.9% 16S rRNA gene similarities). The DNA G + C content of strain TBN4^T and strain TBN5 are 66.1 and 65.4 mol%, respectively. The DNA–DNA hybridization value between strain TBN4^T and strain TBN5 was 94.3%. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain TBN4^T and strain TBN5 represent a novel species in a new genus within the family Halobacteriaceae, for which the name Halorussus rarus gen. nov., sp. nov. is proposed. The type strain is TBN4^T (=CGMCC 1.10122^T = JCM 16429^T).     

A genomic overview including polyphasic taxonomy of Thalassoroseus pseudoceratinae gen. nov., sp. nov. isolated from a marine sponge,Pseudoceratina sp.

A pink-coloured, salt- and alkali-tolerant planctomycetal strain (JC658^T) with oval to pear-shaped, motile, aerobic, Gram-negative stained cells was isolated from a marine sponge, Pseudoceratina sp. Strain JC658^T shares the highest 16S rRNA gene sequence identity with Maioricimonas rarisocia Mal4^T (<?89.2%) in the family Planctomycetaceae. The genomic analysis of the new strain indicates its biotechnological potential for the production of various industrially important enzymes, notably sulfatases and carbohydrate-active enzymes (CAZymes), and also potential antimicrobial compounds. Several genes encoding restriction-modification (RM) and CRISPR-CAS systems are also present. NaCl is obligate for growth, of which strain JC658^T can tolerate a concentration up to 6% (w/v). Optimum pH and temperature for growth are 8.0 (range 7.0–9.0) and 25 ºC (range 10–40 °C), respectively. The major respiratory quinone of strain JC658^T is MK6. Major fatty acids are C_16:1ω7c/C_16:1ω6c, C_18:0 and C_16:0. Major polar lipids are phosphatidylcholine, phosphatidyl-dimethylethanolamine and phosphatidyl-monomethylethanolamine. The genomic size of strain JC658^T is 7.36 Mb with a DNA G?+?C?content of 54.6 mol%. Based on phylogenetic, genomic (ANI, AAI, POCP, dDDH), chemotaxonomic, physiological and biochemical characteristics, we conclude that strain JC658^T belongs to a novel genus and constitutes a novel species within the family Planctomycetaceae, for which we propose the name Thalassoroseus pseudoceratinae gen. nov., sp. nov. The novel species is represented by the type strain JC658^T (=?KCTC 72881 ^T?=?NBRC 114371 ^T).

     

Alexandriicola marinus gen. nov., sp. nov., a new member of the family Rhodobacteraceae isolated from marine phycosphere

Two yellow-pigmented bacterial strains, LZ-14 ^T and ABI-LZ29, were isolated from the cultivable phycosphere microbiota of the highly toxic marine dinoflagellate Alexandrium catenella LZT09 and demonstrated obvious microalgae growth-promoting potentials toward the algal host. To elucidate the taxonomic status of the two bioactive bacterial strains, they were subjected to a polyphasic taxonomic characterization. Both strains were found to be Gram-negative, aerobic, rod-shaped and motile; to contain Q-10 as the predominant ubiquinone; summed feature 8, C_16:0, C_18:1 ω7c 11-methyl and summed feature 3 as the major fatty acids; and diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and two unidentified phospholipids as the predominant polar lipids. Based on the phylogenetic analysis, phylogenomic inferences and phenotypic characteristics, the strains could be clearly distinguished from phylogenetically closely related species and formed a distinct monophyletic lineage in the family Rhodobacteraceae. The size of the draft genome of strain LZ-14 ^T is 4.615 Mb, with a DNA G?+?C content of 63.3 mol%. It contains ten predicted secondary metabolite biosynthetic gene clusters and core genes for bacterial exopolysaccharide biosynthesis. Therefore, strain LZ-14 ^T (= CCTCC AB 2017230 ^T?=?KCTC 62342 ^T) represents a novel species of a new genus, for which the name Alexandriicola marinus gen. nov., sp. nov., is proposed.

     

Thermotomaculum hydrothermale gen. nov., sp. nov., a novel heterotrophic thermophile within the phylum Acidobacteria from a deep-sea hydrothermal vent chimney in the Southern Okinawa Trough

A novel heterotrophic, thermophilic bacterium, designated strain AC55^T, was isolated from a deep-sea hydrothermal vent chimney at the Hatoma Knoll in the Okinawa Trough, Japan. Cells of strain AC55^T were non-motile, long rods (2.0- to 6.8-μm long and 0.3- to 0.6-μm wide). The strain was an obligatory anaerobic heterotroph capable of fermentative growth on complex proteinaceous substances. Elemental sulfur was reduced to hydrogen sulfide but did not stimulate growth. Growth was observed between 37 and 60°C (optimum 55°C), pH 5.5 and 8.5 (optimum pH 6.6), and in the presence of 1.5–4.5% (w/v) NaCl (optimum 2.5%, w/v). Menaquinone-7 and -8 were the major respiratory quinones. The G + C content of the genomic DNA from strain AC55^T was 51.6 mol%. The 16S rRNA gene sequence analysis revealed that strain AC55^T was the first cultivated representative of Acidobacteria subdivision 10. Based on the physiological and phylogenetic features of the novel isolate, the genus name Thermotomaculum gen. nov. is proposed, with Thermotomaculum hydrothermale sp. nov. as the type species. The type strain is AC55^T (=JCM 17643^T = DSM 24660^T = NBRC 107904^T).     

Geomesophilobacter sediminis gen. nov., sp. nov., Geomonas propionica sp. nov. and Geomonas anaerohicana sp. nov., three novel members in the family Geobacterecace isolated from river sediment and paddy soil

Bacteria in the family Geobacteraceae have been proven to fill important niches in a diversity of anaerobic environments and global biogeochemical processes. Here, three bacterial strains in this family, designated Red875^T, Red259^T, and Red421^T were isolated from river sediment and paddy soils in Japan. All of them are Gram-staining-negative, strictly anaerobic, motile, flagellum-harboring cells that form red colonies on agar plates and are capable of utilizing Fe(III)-NTA, Fe(III) citrate, ferrihydrite, MnO₂, fumarate, and nitrate as electron acceptors with acetate, propionate, pyruvate, and glucose as electron donors. Phylogenetic analysis based on the 16S rRNA gene and 92 concatenated core proteins sequences revealed that strains Red259^T and Red421^T clustered with the type strains of Geomonas species, whereas strain Red875^T formed an independent lineage within the family Geobacteraceae. Genome comparison based on  average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values clearly distinguished these three strains from other Geobacteraceae members, with lower values than the thresholds for species delineation. Moreover, strain Red875^T also shared low average amino acid identity (AAI) and percentage of conserved proteins (POCP) values with the type species of the family Geobacteraceae. Based on these physiological, chemotaxonomic, and phylogenetic distinctions, we propose that strain Red875^T (=NBRC 114290^T = MCCC 1K04407^T) represents a novel genus in the family Geobacteraceae, namely, Geomesophilobacter sediminis gen. nov., sp. nov., and strains Red259^T (=NBRC 114288^T = MCCC 1K05016^T) and Red421^T (=NBRC 114289^T = MCCC 1K06216^T) represent two novel independent species in the genus Geomonas, namely, Geomonas propionica sp. nov. and Geomonas anaerohicana sp. nov., respectively.     

Anaerocolumna sedimenticola sp. nov., isolated from fresh water sediment

Strain CBA3638^T was isolated from the Geum River sediment, Republic of Korea. The cells of strain CBA3638^T were Gram-stain-positive, strictly anaerobic, rod-shaped, and 0.5–1.0 μm wide, and 4.0–4.5 μm long. Optimal growth occurred at 37 °C, pH 7.0, and 1.0% (w/v) NaCl. Based on the 16S rRNA gene sequence, the phylogenetic analysis showed that strain CBA3638^T belongs to the genus Anaerocolumna in the family Lachnospiraceae, and is most closely related to Anaerocolumna cellulosilytica (94.6–95.0%). The DDH value with A. cellulosilytica SN021^T showed 15.0% relatedness. The genome of strain CBA3638^T consisted of one circular chromosome that is 5,500,435 bp long with a 36.7 mol% G?+?C content. The genome contained seven 16S-5S-23S rRNA operons and one antibiotic resistance-related transporter gene (mefA). Quinones were not detected. The predominant cellular fatty acids were C_16:0 and C_14:0 and the polar lipids were diphosphatidylglycerol, phosphatidylcholine, and uncharacterised polar lipids. Based on the polyphasic taxonomic analysis, we propose strain CBA3638^T as a novel species in the genus Anaerocolumna, with the name Anaerocolumna sedimenticola sp. nov. The type strain is CBA3638^T (=?KACC 21652^T?=?DSM 110663^T).

     

Sediminihabitans luteus gen. nov., sp. nov., a new member of the family Cellulomonadaceae isolated from sea sediment

Two novel Gram-positive actinobacteria, designated H97-3^T and H83-5, were isolated from marine sediment samples and their taxonomic positions were investigated by a polyphasic approach. Both strains formed vegetative hyphae in the early phase of growth but the hyphae eventually fragmented into coccoid cells. The peptidoglycan type was found to be A4α. The predominant menaquinone was MK-9(H₄), and the major fatty acids were anteiso-C_15:0, anteiso-C_17:0 and C_16:0. The DNA G+C content was 74.0–74.9 mol %. 16S rRNA gene sequencing analysis revealed that strains H97-3^T and H83-5 represented novel members of the family Cellulomonadaceae. Their nearest phylogenetic neighbours were the members of the genus Oerskovia, with a similarity of 98.3–98.4 %. However, strains H97-3^T and H83-5 were distinguishable from the members of the genus Oerskovia and the other genera of the family Cellulomonadaceae in terms of chemotaxonomic characteristics and phylogenetic relationship. The result of the DNA–DNA hybridization indicated that strains H97-3^T and H83-5 belonged to the same species. Therefore, strains H97-3^T and H83-5 represent a novel genus and species of the family Cellulomonadaceae, for which the name Sediminihabitans luteus gen. nov., sp. nov. is proposed. The type strain of S. lutes is H97-3^T (=NBRC 108568^T = DSM 25478^T).     

Microcella flavibacter sp. nov., isolated from marine sediment,and reclassification of Chryseoglobus frigidaquae,Chryseoglobus indicus,and Yonghaparkia alkaliphila as Microcella frigidaquae comb. nov., Microcella indica nom. nov., and Microcella alkalica nom. nov.

A novel Gram-staining positive, aerobic, rod-shaped, non-motile and yellow-pigmented actinobacterium, designated strain WY83^T, was isolated from a marine sediment of Indian Ocean. Strain WY83^T grew optimally at 30–35 °C, pH 7–8 and with 0–3% (w/v) NaCl. The predominant menaquinones were MK-10, MK-11 and MK-12, and the major fatty acids were C_19:1 ω9c/C19:1 ω11c, anteiso-C_15:0, C_17:0 3OH, and iso-C_16:0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid. The cell-wall peptidoglycan contained lysine as a diamino acid. The DNA G?+?C content was 72.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and ninety-two bacterial core genes indicated that strain WY83^T formed an evolutionary lineage with Chryseoglobus frigidaquae JCM 14730^T, Chryseoglobus indicus CTD02-10-2^T, Yonghaparkia alkaliphila JCM 15138^T, Microcella alkaliphila DSM 18851^T and Microcella putealis DSM 19627^T within the radiation enclosing members of the family Microbacteriaceae. All pairwise percentage of conserved proteins between strain WY83^T and the closely related phylogenetic neighbors were greater than 65%. The average nucleotide identity and in silico DNA–DNA hybridization values were both below the thresholds used for the delineation of a new species. On the basis of the evidence presented, strains WY83^T, Y. alkaliphila JCM 15138^T, C. frigidaquae JCM 14730^T, M. alkaliphila DSM 18851^T and M. putealis DSM 19627^T should belong to different species of the same genus. Strain WY83^T represents a novel species of the genus Microcella, for which the name Microcella flavibacter sp. nov. is proposed. The type strain is WY83^T (=?KCTC 39637^T?=?MCCC 1A07099^T). Furthermore, Chryseoglobus frigidaquae, Chryseoglobus indicus, and Yonghaparkia alkaliphila were reclassified as Microcella frigidaquae comb. nov., Microcella indica nom. nov., and Microcella alkalica nom. nov., respectively.

     

Halobellus ruber sp. nov., a deep red-pigmented extremely halophilic archaeon isolated from a Korean solar saltern

A novel halophilic archaeon, strain MBLA0160^T, was isolated from a solar saltern in Sorae, Republic of Korea. The cells are deep-red pigmented, Gram-negative, rod shaped, motile, and lysed in distilled water. The strain MBLA0160^T grew at 25–45 °C (optimum 37 °C), in 15–30% (w/v) NaCl (optimum 20%) and 0.1–1.0 M MgCl₂ (optimum 0.3–0.5 M) at pH 5.0–9.0 (optimum 7.0). Phylogenetic analysis based on the 16S rRNA sequence showed that this strain was related to two species within the genus Halobellus (Hbs.), with 98.4% and 95.8% similarity to Hbs. salinus CSW2.24.4 ^T and Hbs. clavatus TNN18^T, respectively. The major polar lipids of the strain MBLA160^T were phosphatidylglycerol, phosphatidylglycerol sulfate, and phosphatidylglycerol phosphate methyl ester. The genome size, G?+?C content, and N50 value of MBLA0160^T were 3.49 Mb, 66.5 mol%, and 620,127 bp, respectively. According to predicted functional proteins of strain MBLA0160^T, the highest category was amino acid transport and metabolism. Genome rapid annotation showed that amino acid and derivatives was the most subsystem feature counts. Pan-genomic analysis showed that strain MBLA0160^T had 97 annotated unique KEGG, which were mainly included metabolism and environmental information processing. Ortholog average nucleotide identities (OrthoANI) and in silico DNA-DNA hybridization (isDDH) values between the strain MBLA0160^T and other strains of the genus Halobellus were under 84,4% and 28.1%, respectively. The genome of strain MBLA0160^T also contain the biosynthetic gene cluster for C₅₀ carotenoid as secondary metabolite. Based on the phylogenetic, phenotypic, chemotaxonomic properties, and comparative genomic analyses, strain MBLA0160^T is considered to represent a novel species of the genus Halobellus, for which the name Halobellus ruber sp. nov. is proposed. The type strain is MBLA0160^T (=?KCTC 4291 ^T?=?JCM 34172 ^T).

     

Rufibacter tibetensis gen. nov., sp. nov., a novel member of the family Cytophagaceae isolated from soil

A red-pigmented, Gram-negative, strictly aerobic, rod-shaped bacterium which was motile by gliding, designated strain 1351^T, was isolated from the soil of Lengduo, Tibet in China and subjected to a polyphasic taxonomic analysis. The isolate grows optimally at 30°C and pH 7. It grows with NaCl tolerated up to 1.5% (optimum, 0.5%). Phylogenetic analysis based on the 16S rRNA gene sequence shows that strain 1351^T is closely related to members of the family ‘Cytophagaceae’ closest sequence similarity was observed with similarity with Adhaeribacter terreus (91.8%). The major whole-cell fatty acids are summed feature 4 (containing anteiso-C_17:1 B and/or iso-C_17:1 I, 29.2%), summed feature 3 (containing C_16:1ω6c and/or C_16:1ω7c, 13.0%) and iso-C_15:0 (12.0%). The predominant menaquinone of strain 1351^T is menaquinone-7 (MK-7) and the G+C content of the DNA is 46.8 mol%. According to the phylogenetic evidence and phenotypic data, strain 1351^T is considered to represent a new genus and species of the family ‘Cytophagaceae’ for which the name Rufibacter tibetensis gen nov., sp. nov. is proposed. The type species is R. tibetensis and the type strain is 1351^T (=CCTCC AB 208084^T = NRRL B-51285^T).     

Characterization of Microaerobacter geothermalis gen. nov., sp. nov., a novel microaerophilic, nitrate- and nitrite-reducing thermophilic bacterium isolated from a terrestrial hot spring in Tunisia

A novel thermophilic anaerobic and microaerophilic bacterium (optimal growth in the presence of 5–10% O₂), strain Nad S1^T was isolated from the terrestrial hot spring of Hammam Sidi Jdidi, Nabeul, Tunisia. Cells were motile rods having a Gram-positive cell wall structure. Strain Nad S1^T grew optimally at 55°C (range 37–70°C). Optimum pH for growth was 6.5–7.0. It was halotolerant growing with NaCl up to 7% (optimum concentration 1.5–3.0%). It grew chemoorganotrophically on various carbohydrates, organic-acids and amino-acids as energy sources, or chemolithotrophically on H₂ using nitrate, as terminal electron acceptor. Beside oxygen (under microaerobic conditions) and nitrate, nitrite was also used. Nitrate was completely reduced to N₂. No fermentation occurred. The genomic DNA G + C content was 41.8 mol%. Based on 16S rRNA gene sequence analysis, strain Nad S1^T belongs to the Bacillaceae family within the class ‘Bacilli’. Because of its phylogenetic and phenotypic characteristics, we propose this isolate to be assigned as a novel genus and a novel species within the domain Bacteria, Microaerobacter geothermalis gen. nov., sp. nov. The type strain is Nad S1^T (=DSM 22679^T =JCM 16213^T).     

Cysteiniphilum marinum sp. nov., isolated from coastal seawater

Six aerobic Gram-negative bacteria were isolated from seawater in Guangdong Province, P.R. China. Cells were observed to be Gram-negative, aerobic, non-motile and non-spore forming. Growth of the designated type strain 19X3-30^T occurred at a temperature range of 14–37 °C (optimum, 28 °C), a pH range of 6.0–8.0 (optimum, pH 7) and up to 7.5% NaCl (optimum, 1.5%; w/v), and was enhanced by CO₂ and L-cysteine supplementation. The major polar lipids identified in strain 19X3-30^T were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The principal cellular fatty acids profile showed the presence of anteiso-C_15:0, anteiso-C_17:0 and C_18:0 (>?8% of total fatty acids), and the respiratory quinone was ubiquinone 8 (UQ-8). According to the analysis of 16S rRNA gene sequences, these strains represented a novel species within the family Fastidiosibacteraceae, sharing maximum similarities with Cysteiniphilum litorale DSM 101832^T (96.6%) and Cysteiniphilum halobium DSM 103992^T (95.3%). Phylogenetic dendrograms based on 16S rRNA gene and protein marker genes from the genomic sequences both indicated that the strains formed a monophyletic lineage closely linked to the genus Cysteiniphilum, which was also supported by the UPGMA dendrogram based on the MALDI-TOF MS profile. The genomic DNA G?+?C contents of six strains ranged from 38.0% to 38.1%. Based on different taxonomic genomic metrics, phylogeny and phenotypic features, we propose that the strains warrant the assignment to a novel species, for which the name Cysteiniphilum marinum sp. nov. is proposed. The type strain is 19X3-30^T (=?KCTC 82154^T?=?CGMCC 1.18585^T).

     

Rhodoflexus caldus gen. nov., sp. nov., a new member of the phylum Bacteroidota isolated from a hot spring sediment

A thermophilic bacterium, designated strain SYSU G04325^T, was isolated from a hot spring sediment in Yunnan, China. Polyphasic taxonomic analyses and whole-genome sequencing were used to determine the taxonomic position of the strain. Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SYSU G04325^T shows high sequence similarity to Thermoflexibacter ruber NBRC 16677^T (86.2%). The strain can be differentiated from other species of the family Thermoflexibacteraceae by its distinct phenotypic and genotypic characteristics. Cells of the strain SYSU G04325^T were observed to be aerobic, Gram-stain negative and filamentous. Growth was found to occur optimally at 45 ºC and pH 7.0. In addition, the respiratory quinone was identified as menaquinone-7, while the major fatty acids (>?10%) were identified as iso-C_15:0, iso-C_17:0 and Summed Feature 9 (iso-C_17:1ω9c). The polar lipids detected included phosphatidylethanolamine, three unidentified phospholipids, one unidentified glycolipid, five unidentified aminolipids and four unidentified polar lipids. The G?+?C content of the genomic DNA was determined to be 47.6% based on the draft genome sequence. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU G04325^T is concluded to represent a novel species of a novel genus in the family Thermoflexibacteraceae, for which the name Rhodoflexus caldus gen. nov., sp. nov. is proposed. The type strain of Rhodoflexus caldus is SYSU G04325^T (=?MCCC 1K06127^T?=?KCTC 82848^T).

     

Lacipirellula parvula gen. nov., sp. nov., representing a lineage of planctomycetes widespread in low-oxygen habitats,description of the family Lacipirellulaceae fam. nov. and proposal of the orders Pirellulales ord. nov., Gemmatales ord. nov. and Isosphaerales ord. nov.

Pirellula-like planctomycetes are ubiquitous aquatic bacteria, which are often detected in anoxic or micro-oxic habitats. By contrast, the taxonomically described representatives of these bacteria, with very few exceptions, are strict aerobes. Here, we report the isolation and characterization of the facultatively anaerobic planctomycete, strain PX69^T, which was isolated from a boreal lake. Its 16S rRNA gene sequence is affiliated with the Pirellula-related Pir4 clade, which is dominated by environmental sequences retrieved from a variety of low-oxygen habitats. Strain PX69^T was represented by ellipsoidal cells that multiplied by budding and grew on sugars, some polysaccharides and glycerol. Anaerobic growth occurred by means of fermentation. Strain PX69^T grew at pH 5.5–7.5 and at temperatures between 10 and 30 °C. The major fatty acids were C18:1ω9c, C16:0 and C16:1ω7c; the major intact polar lipid was dimethylphosphatidylethanolamine. The complete genome of strain PX69^T was 6.92 Mb in size; DNA G + C content was 61.7 mol%. Among characterized planctomycetes, the highest 16S rRNA gene similarity (90.4%) was observed with ‘Bythopirellula goksoyri’ Pr1d, a planctomycete from deep-sea sediments. We propose to classify PX69^T as a novel genus and species, Lacipirellula parvula gen. nov., sp. nov.; the type strain is strain PX69^T (=KCTC 72398^T = CECT 9826^T = VKM B-3335^T). This genus is placed in a novel family, Lacipirellulaceae fam. nov., which belongs to the order Pirellulales ord. nov. Based on the results of comparative genome analysis, we also suggest establishment of the orders Gemmatales ord. nov. and Isosphaerales ord. nov. as well as an emendation of the order Planctomycetales.     

Characterization of Bifidobacterium apousia sp. nov., Bifidobacterium choladohabitans sp. nov., and Bifidobacterium polysaccharolyticum sp. nov., three novel species of the genus Bifidobacterium from honey bee gut

Bifidobacterium is one of the dominating bacterial genera in the honey bee gut, and they are the key degrader of diet polysaccharides for the host. Previous genomic analysis shows that they belong to separate phylogenetic clusters and exhibited different functional potentials in hemicellulose digestion. Here, three novel strains from the genus Bifidobacterium were isolated from the guts of the honey bee (Apis mellifera). Phylogenomic analysis showed that the isolates could be grouped into four phylogenetic clusters. The average nucleotide identity values between strains from different clusters are <95%, while strains in Cluster IV belong to the characterized species Bifidobacterium asteroides. Carbohydrate-active enzyme annotation confirmed that the metabolic capacity for carbohydrates varied between clusters of strains. Cells are Gram-positive rods; they grew both anaerobically and in a CO₂-enriched atmosphere. All strains grew at a temperature range of 20–42 °C, with optimum growth at 35 °C. The pH range for growth was 5–9. Strains from different phylogenetic clusters varied in multiple phenotypic and chemotaxonomic characterizations. Thus, we propose three novel species Bifidobacterium apousia sp. nov. whose type strain is W8102^T (=CGMCC 1.18893 ^T = JCM 34587 ^T), Bifidobacterium choladohabitans sp. nov., whose type strain is B14384H11^T (=CGMCC 1.18892 ^T = JCM 34586 ^T), and Bifidobacterium polysaccharolyticum sp. nov. whose type strain is W8117^T (=CGMCC 1.18894 ^T = JCM 34588 ^T).     

Rubidimonas crustatorum gen. nov., sp. nov., a novel member of the family Saprospiraceae isolated from a marine crustacean

A strictly aerobic, Gram-negative, reddish-orange pigmented, non-motile and rod-shaped bacterium, designated AK17-053^T was isolated from a marine crustacean (Squillidae) living on tidal flats on the coast of the Ariake Sea, Nagasaki, Japan. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the novel isolate could be affiliated with the family Saprospiraceae of the phylum Bacteroidetes and that it showed highest sequence similarity (84%) with Lewinella marina MKG-38^T. The strain could be differentiated phenotypically from recognized members of the family Saprospiraceae. The G+C content of DNA was 55.3 mol%, MK-7 was the major menaquinone and iso-C_15:0 and C_16:1ω7c were the major fatty acids. On the basis of polyphasic taxonomic studies, it was concluded that strain AK17-053^T represents a new genus of the family Saprospiraceae. We propose the name Rubidimonas crustatorum gen. nov., sp. nov. for this strain; its type strain is AK17-053^T (= MBIC08356^T = NBRC 107717^T).     

Janibacter alkaliphilus sp. nov., isolated from coral Anthogorgia sp

A novel actinobacterium, designated strain SCSIO 10480^T, was isolated from a gorgonian coral sample of Anthogorgia sp. Phylogenetic and phenotypic properties of the organism supported that it belonged to the genus Janibacter. Phylogenetic analysis indicated that the levels of 16S rRNA gene sequence similarity between strain SCSIO 10480^T and other type strains of recognized members of the genus Janibacter were 96.0–97.8 %. Growth in the presence of up to 17 % (w/v) NaCl and optimally at pH 9.0–10.0 was a distinctive characteristic of strain SCSIO 10480^T. Other biochemical and physiological properties and the fatty acid profile also differentiated the isolate from other members of Janibacter species. Based on the results obtained in this study, we propose that strain SCSIO 10480^T should be classified within a novel species of the genus Janibacter, for which the name Janibacter alkaliphilus sp. nov. is proposed, with SCSIO 10480^T (=CCTCC AB 2011027^T = DSM 24723^T) as the type strain.     

Gaiella occulta gen. nov., sp. nov., a novel representative of a deep branching phylogenetic lineage within the class Actinobacteria and proposal of Gaiellaceae fam. nov. and Gaiellales ord. nov

Two isolates, with an optimum growth temperature of about 35-37 °C and an optimum pH for growth between 6.5 and 7.5, were recovered from a deep mineral water aquifer in Portugal. Strains form rod-shaped cells and were non-motile. These strains were non-pigmented, strictly aerobic, catalase and oxidase positive. Strains F2-233^T and F2-223 assimilated carbohydrates, organic acids and amino acids. Major fatty acids were novel iso internally branched such as 17:0 iso 10-methyl, 17:0 iso and 15:0 iso 8-methyl. The peptidoglycan contained meso-diaminopimelic acid and menaquinone MK-7 was the major respiratory quinone. Analysis of the 16S rRNA gene shows the strains to cluster with species of the genera Thermoleophilum, Patulibacter, Conexibacter and Solirubrobacter to which they have pairwise sequence similarity in the range 87-88%. Based on 16S rRNA gene sequence analysis, physiological and biochemical characteristics we describe a new species of a novel genus represented by strain F2-233^T (=CECT 7815^T = LMG 26412^T) for which we propose the name Gaiella occulta gen. nov., sp. nov. We also propose that this organism represents a novel family named Gaiellaceae fam. nov. of a novel order named Gaiellales ord. nov.     

Description of the novel perchlorate-reducing bacteria Dechlorobacter hydrogenophilus gen. nov., sp. nov. and Propionivibrio militaris, sp. nov.

Novel dissimilatory perchlorate-reducing bacteria (DPRB) were isolated from enrichments conducted under conditions different from those of all previously described DPRB. Strain LT-1^T was enriched using medium buffered at pH 6.6 with 2-(N-morpholino)ethanesulfonic acid (MES) and had only 95% 16S rRNA gene identity with its closest relative, Azonexus caeni. Strain MP^T was enriched in the cathodic chamber of a perchlorate-reducing bioelectrical reactor (BER) and together with an additional strain, CR (99% 16S rRNA gene identity), had 97% 16S rRNA gene identity with Propionivibrio limicola. The use of perchlorate and other electron acceptors distinguished strains MP^T and CR from P. limicola physiologically. Strain LT-1^T had differences in electron donor utilization and optimum growth temperatures from A. caeni. Strains LT-1^T and MP^T are the first DPRB to be described in the Betaproteobacteria outside of the Dechloromonas and Azospira genera. On the basis of phylogenetic and physiological features, strain LT-1^T represents a novel genus in the Rhodocyclaceae; strain MP^T represents a novel species within the genus Propionivibrio. The names Dechlorobacter hydrogenophilus gen. nov., sp. nov and Propionivibrio militaris sp. nov. are proposed.