International Journal of Systematic and Evolutionary Microbiology

A motile, rod-shaped and anaerobic strain WK13T was isolated from a secondary root canal infection of a human tooth. WK13T cells were Gram-stain-negative, catalase-positive and oxidase-negative. The major fatty acids (≥ 5.0%) were C16 : 0, C18 : 0, C16 : 1  ω7c, C18 : 1  ω9c and C18 : 2  ω6,9c. The DNA G+C content was 57.94 mol%. The major polar lipids were phosphatidylethanolamine, phosphatidylserine, diphosphatidylglycerol, phosphatidylcholine and lysophosphatidylcholine. There were no respiratory quinones detectable. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain WK13T belongs to the class Betaproteobacteria. WK13T showed a 93.6% and 93.5% 16S rRNA gene sequence similarity to the most closely related cultured species, Propionivibrio pelophilus strain DSM 12018T and Propionivibrio dicarboxylicus strain DSM 5885T, respectively. On the basis of physiological and biochemical data, the isolate is considered to represent a novel species of a new genus in the class Betaproteobacteria, for which we propose the name Dentiradicibacter hellwigii gen. nov., sp. nov. The type strain is WK13T (=DSM 112713T=NCTC 14938T).

Understanding the characteristics of microbes during long-term space missions is essential for safeguarding the health of astronauts and maintaining the functionality of spacecraft. In this study, a Gram-positive, aerobic, spore-forming, rod-shaped strain JL1B1071T was isolated from the surface of hardware on the China Space Station. This strain belongs to the genus Niallia, with its closest relative being Niallia circulans ATCC 4513T. The genome of JL1B1071T is 5 166 230 bp in size, with a G+C content of 35.6 mol%. The average nucleotide identity and digital DNA–DNA hybridization values between JL1B1071T and N. circulans ATCC 4513T are 83.3 and 27.5%, respectively, both below the recommended thresholds for species delineation. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0. The major quinone was menaquinone-7 (MK-7). Notably, strain JL1B1071T demonstrates a unique ability to hydrolyse gelatin, suggesting that it can utilize gelatin as a substrate in nutrient-limited environments. Genomic analysis of JL1B1071T revealed two conserved signature indels in the GAF domain-containing protein and DNA ligase D protein, which are specific to the genus Niallia. Additionally, structural and functional differences in proteins BshB1 and SplA were identified, which may enhance biofilm formation, oxidative stress response and radiation damage repair, thereby aiding its survival in the space environment. Based on phenotypic, physiological and chemotaxonomic characteristics, as well as genome annotation, strain JL1B1071T was considered a novel species within the genus Niallia and is proposed to be named Niallia tiangongensis sp. nov. The type strain is JL1B1071T (=GDMCC 1.4642=KCTC 43715).

Opinion 131 addresses a Request for an Opinion asking the Judicial Commission to conserve the genus name Proteus Hauser 1885 (Approved Lists 1980) over its earlier homonym, the protozoan genus name Proteus Müller 1786. The Judicial Commission agrees that the later homonym is illegitimate and that the replacement of the prokaryotic name Proteus would be undesirable. It is also concluded that Proteus Müller 1786 is an objectively invalid name under the International Code of Zoological Nomenclature. Judicial Opinions 9, 12 and 130 serve as precedents for the conservation of Proteus Hauser 1885 (Approved Lists 1980) over Proteus Müller 1786. This action is taken here and makes the prokaryotic name Proteus legitimate.

Two Gram-stain-negative, facultative anaerobic, rod-shaped and non-gliding bacteria, designated as HL-DH10T and HL-DH14, were isolated from the halophyte Suaeda japonica in a mudflat, Republic of Korea. Based on the results of 16S rRNA gene pairwise analysis, the two isolates were the members of the family Flavobacteriaceae, and Aestuariibaculum suncheonense SC17T was the most closely related to strains HL-DH10T and HL-DH14 with 96.3% and 95.4% sequence similarity, respectively. The average nt identity and digital DNA–DNA hybridization values between strains HL-DH10T and HL-DH14 and other related species were all less than 79.2% and 21.9%, respectively. The genomic DNA G+C contents of strains HL-DH10T and HL-DH14 were 32.0% and 31.5%, respectively. Cells of these strains showed optimal growth at 25 °C, pH 6.5–7.0 and 2.5–4.0% (w/v) sea salts. The major respiratory quinone was menaquinone-6. The major cellular fatty acids were iso-C15:0 (14.0–16.0%), iso-C15:1 G (10.0–12.0%), iso-C17:0 3-OH (12.4–13.9%), iso-C15:0 3-OH (11.8–14.9%) and anteiso-C15:0 (9.4–10.6%). The polar lipids consisted of phosphatidylethanolamine, an unidentified aminophospholipid, two to three unidentified aminolipids and three unidentified lipids. The comprehensive phylogenetic, genomic, phenotypic and chemotaxonomic results indicate that strains HL-DH10T and HL-DH14 are considered to represent a novel genus of Flavobacteriaceae. Hence, we propose the novel genus Thalassobellus suaedae gen. nov., sp. nov. The type strain is HL-DH10T (=KCCM 90512T=JCM 36598T).

In the domain Bacteria, one of the largest, most diverse and environmentally ubiquitous phylogenetic groups, Candidatus Patescibacteria (also known as candidate phyla radiation/CPR), remains poorly characterized, leaving a major knowledge gap in microbial ecology. We recently discovered a novel cross-domain symbiosis between Ca. Patescibacteria and Archaea in highly purified enrichment cultures and proposed Candidatus taxa for the characterized species, including Ca. Minisyncoccus archaeophilus and the corresponding family Ca. Minisyncoccaceae. In this study, we report the isolation of this bacterium, designated strain PMX.108T, in a two-strain co-culture with a host archaeon, Methanospirillum hungatei strain DSM 864T (JF-1T), and hereby describe it as the first representative species of Ca. Patescibacteria. Strain PMX.108T was isolated from mesophilic methanogenic sludge in an anaerobic laboratory-scale bioreactor treating synthetic purified terephthalate- and dimethyl terephthalate-manufacturing wastewater. The strain could not grow axenically and is obligately anaerobic and parasitic, strictly depending on M. hungatei as a host. The genome was comparatively large (1.54 Mbp) compared to other members of the clade, lacked some genes involved in the biosynthesis pathway and encoded type IV pili-related genes associated with the parasitic lifestyle of ultrasmall microbes. The G+C content of the genomic DNA was 36.6 mol%. Here, we report the phenotypic and genomic properties of strain PMX.108T; we propose Minisyncoccus archaeiphilus gen. nov., sp. nov. to accommodate this strain. The type strain of the species is PMX.108T (=JCM 39522T). We also propose the associated family, order, class and phylum as Minisyncoccaceae fam. nov. Minisyncoccales nov., Minisyncoccia class. nov. and Minisyncoccota phyl. nov. within the bacterial kingdom Bacillati.

A novel yellow-coloured bacterial strain MA10T was isolated from mangrove sediment and subjected to polyphasic taxonomic identification. Strain MA10T was Gram-negative, rod-shaped, catalase-positive and oxidase-positive. Carotenoid pigment was present, and flexirubin-type pigment was absent. The 16S rRNA gene of strain MA10T had the highest sequence similarity with Tamlana crocina HST1-43T of 94.5%. The genome size was 3.77 Mbp with a genomic G+C content of 36.3%. The phylogenetic analysis of the 16S rRNA gene sequence and whole-genome sequence showed that strain MA10T belonged to the genus Tamlana of the family Flavobacteriaceae and tightly clustered with T. crocina HST1-43T. The digital DNA–DNA hybridization value and average nucleotide identity value between strain MA10T and T. crocina HST1-43T were 20.4 and 76.7%, respectively. The major menaquinone was MK-6. The major fatty acids (>10 %) were iso-C15:0 (41.6%) and iso-C15:1 G (16.8%). The polar lipids consisted of phosphatidylethanolamine, two unidentified aminolipids and three unidentified lipids. Based on the present polyphasic taxonomic study, strain MA10T was considered to represent a novel species of the genus Tamlana, for which the name Tamlana flava sp. nov. was proposed. The type strain was MA10T (=MCCC 1K09289T=KCTC 102321T). Additionally, the phylogeny of the 16S rRNA gene and whole-genome sequences found that the hitherto described nine species of the genus Tamlana and Algibacter onchidii presented polyphyletic clades, which could be divided into five different genera. The average amino acid identity value of 80% was chosen as the boundary of the five genera. Thus, except for the genus Tamlana, four novel genera named Allotamlana gen. nov., Cognatitamlana gen. nov., Neotamlana gen. nov. and Pseudotamlana gen. nov. were proposed. This study provided valuable taxonomic analysis of the genus Tamlana.

A Gram-stain-negative, aerobic and rod-shaped bacterium, designated as HZG-20T, was isolated from a tidal flat in Zhoushan, Zhejiang Province, China. The 16S rRNA sequence similarities between strain HZG-20T and Pikeienuella piscinae RR4-56T, Coraliihabitans acroporae NNCM2T, Parvibaculum indicum P31T and Zhengella mangrovi X9-2-2T were 98.9, 91.7, 91.0 and 91.0%, respectively. Colonies of strain HZG-20T were 1.4 mm in diameter, milky white, round, smooth and convex after cultivating on marine agar at 30 °C for 48 h. Cells were catalase and oxidase-negative. Growth occurred at 15–37 ℃ (optimum, 28 ℃), pH 5.0–9.0 (optimum, pH 6.0–8.0) and with 0–8% (w/v) NaCl (optimum, 1–3%). It contained Menaquinone-8 (H2) as the sole respiratory quinone, and C16:0 (11.8–13.6%), C18:1  ω9c (6.8–13.3%) and C15:0 anteiso (10.9–27.7%) as the major cellular fatty acids. The main polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid, one unidentified phosphoglycolipid, two unidentified glycolipids (GL1–GL2) and three unidentified lipids (L1–L3). The genome of strain HZG-20T was 3 835 886 bp in length, comprised 3746 protein-coding genes, with DNA G+C content of 67.1 mol%. The phylogenetic and phylogenomic trees indicated that strain HZG-20T formed an independent and stable clade with P. piscinae RR4-56T. However, the average nucleotide identity, digit DNA–DNA hybridization and average amino acid identity values between strain HZG-20T and P. piscinae RR4-56T, C. acroporae NNCM2T, P. indicum P31T and Z. mangrovi X9-2-2T were 81.6, 71.1, 68.7 and 69.5%; 23.0, 18.5, 17.9 and 17.5%; and 78.2, 56.8, 56.5 and 61.9%, respectively, together with distinct chemotaxonomic features, indicating strain HZG-20T should not be assigned to known genera. As a result, a novel species of a novel genus within the family Paracoccaceae, designated as Paludibacillus litoralis gen. nov., sp. nov., was proposed. The type strain is HZG-20T (MCCC 1K08468T=KCTC 82692T).

Small, obligately anaerobic strains 13CB8CT, 13CB11CT, 13CB18CT and 13GAM1GT were isolated from a faecal sample in a patient with Parkinson’s disease with a history of duodenal resection. After conducting a comprehensive polyphasic taxonomic analysis including genomic analysis, we propose the establishment of one new genus and four new species. The novel bacteria are Desulfovibrio falkowii sp. nov. (type strain JCM 36128T = DSM 116810T), Porphyromonas miyakawae sp. nov. (type strain JCM 36129T = DSM 116947T), Mediterraneibacter flintii sp. nov. (type strain JCM 36130T = DSM 116866T) and Owariibacterium komagatae gen. nov. sp. nov. (type strain JCM 36131T = DSM 116982T), respectively.

A Gram-stain-negative, non-spore-forming, rod-shaped, obligately anaerobic bacterium, designated strain BP47G, was isolated from the hindgut of a silver drummer (Kyphosus sydneyanus) fish collected from the Hauraki Gulf, New Zealand. Phylogenetic analysis based on the 16S rRNA gene sequence of the isolate indicated that it belonged to the family Oscillospiraceae in the phylum Bacillota. The gene sequence of BP47G was most similar to Oscillibacter valericigenes with 95.23% sequence identity. Isolate BP47G grew on agar medium containing mannitol and fish gut fluid as the sole carbon sources. Clear colonies of ~1 mm diameter grew within a week at 20–28 °C (optimum 28 °C) and pH 7.1–8.5 (optimum 8.5). BP47G tolerated the addition to the medium of up to 1% NaCl. Formate and butyrate were the major fermentation products. The major cellular fatty acids were C12:0, C13:0, iso-C14:0, C16:0 and C16:1 cis 7. Genomic analyses comparing BP47G with its closest relatives indicated low genomic relatedness based on the average nucleotide identity, average amino acid identity, percentage of conserved protein and in silico DNA–DNA hybridization. Supported by the phenotypic and taxonomic characteristics observed in this study, a novel genus and species Bengtsoniella intestinalis gen. nov., sp. nov. is proposed for isolate BP47G (=ICMP 24688=JCM 35770).