Cultivation of anaerobic bacteria: Foundations and principles

A brief history of techniques in anaerobic microbiology are presented leading up to the incorporation of several improvements we have used over the years to improve our culture of anaerobic microorganisms of environmental, industrial and clinical importance. Two overriding aspects from our combined 90 years of experience here are: the better one's control of anaerobic conditions and gas phases, the better results are obtained; techniques can and should be targeted for individual microorganisms and accompanying experiments. Continued improvements in anaerobic microbiology are expected and encouraged for the future.

No Bridge between Us: EXAFS and Computations Confirm Two Distant Iron Ions Comprise the Active Site of Alkane Monooxygenase (AlkB)

Alkane monooxygenase (AlkB) is the dominant enzyme that catalyzes the oxidation of liquid alkanes in the environment. Two recent structural models derived from cryo-electron microscopy (cryo-EM) reveal an unusual active site: a histidine-rich center that binds two iron ions without a bridging ligand. To ensure that potential photoreduction and radiation damage are not responsible for the absence of a bridging ligand in the cryo-EM structures, spectroscopic methods are needed. We present the results of extended X-ray absorption fine structure (EXAFS) experiments collected under conditions where photodamage was avoided. Careful data analysis reveals an active site structure consistent with the cryo-EM structures in which the two iron ions are ligated by nine histidines and separated by at least 5 Å. The EXAFS data were used to inform structural models for molecular dynamics (MD) simulations. The MD simulations corroborate EXAFS observations that neither of the two conserved carboxylate-containing residues (E281 and D190) near the active site are likely candidates for metal ion bridging. Mutagenesis experiments, spectroscopy, and additional MD simulations were used to further explore the role of these carboxylate residues. A variant in which a carboxylate containing residue (E281) was changed to a methyl residue (E281A) showed little change in pre-edge features, consistent with the observation that it is not essential for activity and hence unlikely to serve as a bridging ligand at any point in the catalytic cycle. D190 variants had substantially diminished activity, suggesting an important role in catalysis not yet fully understood.

Comprehensive genomic and phenotypic characterization of thermophilic bacterium Sinimarinibacterium thermocellulolyticum sp. nov. HSW-8T, a cellulase-producing bacterium isolated from hot spring water in South Korea

A thermophilic cellulase-producing bacterium, strain HSW-8T, isolated from hot spring waters in South Korea, was subjected to a taxonomic analysis. Cells of strain HSW-8T were gram-stain-negative, facultatively anaerobic, rod-shaped, with optimum growth at 45 °C, pH 7.0, in the presence of 0% (w/v) NaCl. Strain HSW-8T showed the highest 16S rRNA gene sequence similarity to Sinimarinibacterium flocculans NH6-24T (97.52%), followed by Fontimonas thermophila DSM 23609T (96.97%), Solimonas flava CW-KD 4T (95.24%), and Solimonas variicoloris DSM 15731T (95.18%). Based on 16S rRNA phylogeny, strain HSW-8T is phylogenetically closely related to Fontimonas thermophila DSM 23609T and Sinimarinibacterium flocculans DSM 104150T and could be distinguished from the type species based on their phenotypic properties. The genome length of strain HSW-8T was 3.32 Mbp with a 67.33% G + C content. The average nucleotide identity and digital DNA-DNA hybridization values between strain HSW-8T and its closely related type strains were 75.4-83.2 and 20.2-26.2%, respectively. Summed feature 8 (C18:1ω7c and/or C18:1ω6c), C16:0, and iso-C16:0 identified the major fatty acids (> 10%). Phosphatidylglycerol and phosphatidylethanolamine were demonstrated as the major polar lipids while the respiratory quinone is ubiquinone-8. Strain HSW-8T exhibited multiple adaptations for survival at high temperatures, including diverse potential motility mechanisms and toxin-antitoxin systems, as evidenced by both phenotypic characteristics and genomic analysis. Based on genotypic and phenotypic features, strain HSW-8T (= KCTC 92765T = GDMCC 1.4313T) represents a novel Sinimarinibacterium species, in which the name Sinimarinibacterium thermocellulolyticum sp. nov. is proposed.

Phylogenomics and molecular marker-based analyses of the order Nevskiales: Proposal for the creation of Steroidobacterales ord. nov. and Peristeroidobacter gen. nov

The order Nevskiales, class Gammaproteobacteria, encompasses four families Algiphilaceae, Salinisphaeraceae, Nevskiaceae, and Steroidobacteraceae. The taxonomy of this order is structured from the inferences derived from the 16S rRNA gene and genome-based phylogenetic tree analyses. However, previous taxonomic studies of the order failed to incorporate most of the representatives from other established orders within the class Gammaproteobacteria. Other divergent members within the class Gammaproteobacteria were therefore overlooked. In this study, the taxonomy of the order Nevskiales was revisited using genome-based analyses with an expanded scope of outgroups representing the vast majority of the diversity within the class Gammaproteobacteria. Results from the phylogenetic analyses strongly supported the exclusion of the family Steroidobacteraceae from the order Nevskiales and further implied the assignment of the family into a novel order. In addition, the analyses also supported the reclassification of Steroidobacter gossypii, Steroidobacter soli, Steroidobacter agariperforans, and Steroidobacter agaridevorans into a novel genus. The identified conserved signature indels in 33 protein sequences further reinforced the new taxonomic assignments. Furthermore, the results of the average nucleotide identity and average amino acid identity analyses, together with the phenotypic and genomic characteristics among the members of the genus Steroidobacter also provided evidence supporting the reclassification of the four Steroidobacter species. Based on these results, the family Steroidobacteraceae is proposed to be assigned into a novel order Steroidobacterales ord. nov., and the species S. gossypii, S. soli, S. agariperforans, and S. agaridevorans are proposed to be moved into a novel genus Peristeroidobacter gen. nov. within the family Steroidobacteraceae.

Crystal structure of thermally stable homodimeric cytochrome c'-β from Thermus thermophilus

Cytochrome c'-β is a heme protein that belongs to the cytochrome P460 family and consists of homodimeric subunits with a predominantly antiparallel β-sheet fold. Here, the crystal structure of cytochrome c'-β from the thermophilic Thermus thermophilus (TTCP-β) is reported at 1.74 Å resolution. TTCP-β has a typical antiparallel β-sheet fold similar to that of cytochrome c'-β from the moderately thermophilic Methylococcus capsulatus (MCCP-β). The phenylalanine cap structure around the distal side of the heme is also similar in TTCP-β and MCCP-β, indicating that both proteins similarly bind nitric oxide and carbon monoxide, as observed spectroscopically. Notably, TTCP-β exhibits a denaturation temperature of 117°C, which is higher than that of MCCP-β. Mutational analysis reveals that the increased homodimeric interface area of TTCP-β contributes to its high thermal stability. Furthermore, 14 proline residues, which are mostly located in the TTCP-β loop regions, possibly contribute to the rigid loop structure compared with MCCP-β, which has only six proline residues. These findings, together with those from phylogenetic analysis, suggest that the structures of Thermus cytochromes c'-β, including TTCP-β, are optimized for function under the high-temperature conditions in which the source organisms live.

Flagellatimonas centrodinii gen. nov., sp. nov., a novel member of the family Nevskiaceae isolated from toxin-producing dinoflagellate Centrodinium punctatum

A Gram-stain-negative, aerobic, rod-shaped strain (R2A-3^T) was isolated from the toxin-producing dinoflagellate Centrodinium punctatum and identified as a novel genus and new species based on a polyphasic taxonomic approach. The optimum conditions for growth of the strain were at 25 °C, pH 8.0 and in the presence of 3 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA genes and 92 core genes sets revealed that strain R2A-3^T belongs to the family Nevskiaceae in the class Gammaproteobacteria and represented an independent taxon separated from other genera. The 16S rRNA gene of strain R2A-3^T showed the highest sequence similarity to Polycyclovorans algicola TG408^T (95.2%), Fontimonas thermophila HA-01^T (94.1%) and Sinimarinibacterium flocculans NH6-24^T (93.2%), and less than 92.8 % similarity to other genera in the family Nevskiaceae. The genome length of strain R2A-3^T was 3608892 bp with 65.2 mol% G+C content. Summed feature 8 (comprising C_18 : 1  ω7c and/or C_18 : 1  ω6c) was the major fatty acid (>10 %). Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were detected as the major polar lipids. The major respiratory quinone was ubiquinone-8. According to its phylogenetic, phenotypic, chemotaxonomic and genomic features, strain R2A-3^T represents a new species in the new genus of the family Nevskiaceae. It is recommended to name it Flagellatimonas centrodinii gen. nov., sp. nov. The type strain is R2A-3^T (=KCTC 82469^T=GDMCC 1.2523^T).

Polyphasic taxonomic analysis of Sinimarinibacterium arenosum sp. nov., a halophilic bacterium isolated from marine sediment

A Gram stain-negative, aerobic, motile, rod-shaped bacterial strain, designated CAU 1509T, was isolated from marine sediment, and its taxonomic position was determined using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CAU 1509T formed a distinct lineage within the genus Sinimarinibacterium with the highest 16S rRNA gene sequence similarity to Sinimarinibacterium flocculans NH6-24T (97.0%). Similar to another member of Sinimarinibacterium, ubiquinone-8 (Q-8) was the predominant quinone, whereas C16:0, summed feature 3 (C16:1ω7c/ω6c) and summed feature 8 (C18:1ω7c/ω6c) were the major cellular fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, four unidentified glycolipids and three unidentified aminolipids. Strain CAU 1509T has a genome of 4.54 Mb, including 4251 coding sequences, 6 rRNAs and 50 tRNAs, with a genomic DNA G+C content of 63.2 mol%. Based on its phenotypic, chemotaxonomic and phylogenetic properties, strain CAU 1509T should be classified as a novel species of the genus Sinimarinibacterium, for which the name Sinimarinibacterium arenosum sp. nov. is proposed. The type strain is CAU 1509T (= KCTC 72000T = NBRC 113698T).

Stagnimonas aquatica gen. nov., sp. nov., a new member of the family Nevskiaceae isolated from a freshwater mesocosm

A novel bacterial strain, designated THS-13^T, isolated from a freshwater mesocosm in Taiwan, was characterized by taking a polyphasic taxonomic approach. Cells of strain THS-13^T were Gram-stain-negative, aerobic, rod-shaped, motile by means of a single polar flagellum and formed translucent white coloured colonies. Growth occurred at 20-35 °C (optimum, 25 °C), at pH 5-8 (pH 6) and with 0-2 % NaCl (1 %). Phylogenetic analyses based on 16S rRNA gene and coding sequences of 92 protein clusters revealed that the strain belonged to the family Nevskiaceae in the class Gammaproteobacteria and represented an independent taxon separated from other genera. Strain THS-13^T shared low level of 16S rRNA gene sequence similarity (less than 93.0 %) to members of other genera in the family Nevskiaceae and was most closely related to Nevskia aquatilis F2-63^T (92.9 %). Strain THS-13^T showed less than 73.4 % average nucleotide identity and less than 23.8 % digital DNA-DNA hybridization identity compared to the type strains of related genera within the family Nevskiaceae. The predominant fatty acids were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and iso-C16 : 0. The major isoprenoid quinone was Q-8 and the DNA G+C content was 67.6 mol%. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, an uncharacterized aminophospholipid, an uncharacterized phospholipid and an uncharacterized aminolipid. On the basis of the genotypic and phenotypic data, strain THS-13^T represents a novel species of a new genus in the family Nevskiaceae, for which we propose the name Stagnimonas aquatica gen. nov., sp. nov. The type strain is THS-13^T (=BCRC 81158^T=LMG 30925^T=KCTC 62868^T).

When treated as heterotypic synonyms the names Caryophanaceae Peshkoff 1939 (Approved Lists 1980) and Caryophanales Peshkoff 1939 (Approved Lists 1980) have priority over the names Planococcaceae Krasil'nikov 1949 (Approved Lists 1980) and Bacillales Prévot 1953 (Approved Lists 1980), respectively

The International Code of Nomenclature of Prokaryotes provides rules that govern the way names are to be selected based on priority of valid publication when two or more alternatives (synonyms) are available. However, these rules are not always followed. In the case of the name CaryophanaceaePeshkoff 1939 (Approved Lists 1980), when its nomenclatural type CaryophanonPeshkoff 1939 (Approved Lists 1980) is placed in the same taxon as PlanococcusMigula 1894 (Approved Lists 1980), the nomenclatural type of PlanococcaceaeKrasil'nikov 1949 (Approved Lists 1980), then the two are considered to be heterotypic synonyms and the name which has priority is CaryophanaceaePeshkoff 1939 (Approved Lists 1980). Similarly in the case of the name CaryophanalesPeshkoff 1939 (Approved Lists 1980) when its nomenclatural type CaryophanonPeshkoff 1939 (Approved Lists 1980) is placed in the same taxon as Bacillus Cohn 1872 (Approved Lists 1980), the nomenclatural type of BacillalesPrévot 1953 (Approved Lists 1980), then the two are considered to be heterotypic synonyms and the name which has priority is CaryophanalesPeshkoff 1939 (Approved Lists 1980) While the rules of the International Code of Nomenclature of Prokaryotes are unambiguous in determining the correct names despite the fact that the names CaryophanaceaePeshkoff 1939 (Approved Lists 1980) and CaryophanalesPeshkoff 1939 (Approved Lists 1980) are rarely used.

Stenotrophobium rhamnosiphilum gen. nov., sp. nov., isolated from a glacier, proposal of Steroidobacteraceae fam. nov. in Nevskiales and emended description of the family Nevskiaceae

A Gram-stain-negative strain, designated GT1R17^T, was isolated from an ervoconite sample collected from Gawalong glacier in the Tibet Autonomous Region, PR China. Strain GT1R17^T was catalase- and oxidase-positive, and grew optimally at 20-25°C and pH 7.0. The highest level of 16S rRNA gene sequence similarities were found to members of the genera Nevskia(92.27-93.15 %) and Hydrocarboniphaga(91.92-92.96 %). Phylogenetic analyses based on 16S rRNA gene sequences and genomic data revealed that the strain GT1R17^T belonged to the family Nevskiaceae, but could not be assigned to any known genera. The genomic DNA G+C content was 54.4 mol%. The major fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), summed feature 8 (C18 : 1 ω7c and/or C18 : 1ω6c), C16 : 0, iso-C16 : 0 and summed feature 2 (C14 : 0 3OH and/or iso-C16 : 1 I). The polar lipids were phosphatidylglycerol, phosphatidylethanolamine and one unidentified lipid. The ubiquinone was Q-8. On the basis of the phenotypic, chemotaxonomic, genotypic and phylogenetic data, a novel species of a new genus,Stenotrophobiumrhamnosiphilum gen. nov., sp. nov. within the family Nevskiaceae, is proposed, with GT1R17^T (=CGMCC 1.16137^T=NBRC 113346^T) as the type strain. In addition, phylogenetic analyses revealed that Steroidobacter and Povalibacter formed an independent clade in the order Nevskiales and were away from the families Nevskiaceae, Algiphilaceae and Salinisphaeraceae. Therefore, we propose to remove Steroidobacter and Povalibacter from the family Nevskiaceae and propose a new family Steroidobacteraceae in the order Nevskiales.

Novel arsenic-transforming bacteria and the diversity of their arsenic-related genes and enzymes arising from arsenic-polluted freshwater sediment

Bacteria are essential in arsenic cycling. However, few studies have addressed 16S rRNA and arsenic-related functional gene diversity in long-term arsenic-contaminated tropical sediment. Here, using culture-based, metagenomic and computational approaches, we describe the diversity of bacteria, genes and enzymes involved in AsIII and AsV transformation in freshwater sediment and in anaerobic AsIII- and AsV-enrichment cultures (ECs). The taxonomic profile reveals significant differences among the communities. Arcobacter, Dechloromonas, Sedimentibacter and Clostridium thermopalmarium were exclusively found in ECs, whereas Anaerobacillus was restricted to AsV-EC. Novel taxa that are both AsV-reducers and AsIII-oxidizers were identified: Dechloromonas, Acidovorax facilis, A. delafieldii, Aquabacterium, Shewanella, C. thermopalmarium and Macellibacteroides fermentans. Phylogenic discrepancies were revealed among the aioA, arsC and arrA genes and those of other species, indicating horizontal gene transfer. ArsC and AioA have sets of amino acids that can be used to assess their functional and structural integrity and familial subgroups. The positions required for AsV reduction are conserved, suggesting strong selective pressure for maintaining the functionality of ArsC. Altogether, these findings highlight the role of freshwater sediment bacteria in arsenic mobility, and the untapped diversity of dissimilatory arsenate-reducing and arsenate-resistant bacteria, which might contribute to arsenic toxicity in aquatic environments.

The nomenclatural type of the genus Methanocorpusculum Zellner et al. 1988 and the selection of the correct name

A recent Request for an Opinion has raised the issue of the inter-relationship between Methanocorpusculum parvum Zellner et al. 1988, the type species of the genus Methanocorpusculum Zellner et al. 1988 as defined at the time of valid publication of the genus name and the subsequent recognition of Methanocorpusculum aggregans (Ollivier et al., 1985) Xun et al.1989 as an earlier heterotypic synonym. Examination of the relevant literature indicates that there are a number of misunderstandings that have arisen. In particular misinterpretation of Rule 15 of the International Code of Nomenclature of Prokaryotes continues to be a source of confusion. Additional problems centre on whether the nomenclatural type of a taxon continues to be the nomenclatural type even if that name is not treated as the correct name and would not appear in a list of names in a given classification. It would be appropriate to clarify these issues.

Priority of the genus name Clostridium Prazmowski 1880 (Approved Lists 1980) vs Sarcina Goodsir 1842 (Approved Lists 1980) and the creation of the illegitimate combinations Clostridium maximum (Lindner 1888) Lawson and Rainey 2016 and Clostridium ventriculi (Goodsir 1842) Lawson and Rainey 2016 that may not be used

In a recent publication that attempts to deal with the growing problem of taxa being added to the genus Clostridium that are outside of Clostridium (16S rRNA) group I, a solution is proposed that seeks to limit the genus Clostridium Prazmowski 1880 (Approved Lists 1980) to a small number of species 'related' to the type species, Clostridium butyricum Prazmowski 1880 (Approved Lists 1980). It has been proposed that this genus should also include members of the genus Sarcina Goodsir 1842 (Approved Lists 1980), Sarcinamaxima Lindner 1888 (Approved Lists 1980) and Sarcinaventriculi Goodsir 1842 (Approved Lists 1980), the latter being the nomenclatural type of the genus Sarcina Goodsir 1842 (Approved Lists 1980). In making proposals to treat the genus name Sarcina Goodsir 1842 (Approved Lists 1980) as a synonym of ClostridiumPrazmowski 1880 (Approved Lists 1980), reference is made to the wording of the International Code of Nomenclature of Bacteria. However, while that wording is factually correct, other parts of the Code are relevant to this issue and clearly indicate that the proposed course of action is not sanctioned by texts that have not been directly made reference to. Rather than avoiding confusion it has been contributed to, and it is necessary to document where the problems lie.

Sinimarinibacterium flocculans gen. nov., sp. nov., a gammaproteobacterium from offshore surface seawater

Two aerobic, rod-shaped, non-motile, non-sporulating and Gram-staining-negative bacterial strains, namely NH6-24T and Za3-11, were isolated from the surface seawater of the South China Sea and the estuary of the Yangtze River, respectively. The two isolates grew at 14–44 °C (optimum 37–40 °C) and pH 6.0–8.5 (optimum pH 7.0–7.5). The sea salt ranges for growth were 0.5–10 % (w/v) (optimum 1–2.5 %) for strain NH6-24T and 0–12 % (w/v) (optimum 0.5–4.5 %) for strain Za3-11.Both strains could grow in the absence of NaCl. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that the two isolates showed closest affinity to the genera Fontimonas (96.0 %) and Solimonas (94.1–95.1 %) and formed a single lineage in the cluster of the family Solimonadaceae. The predominant isoprenoid quinone was ubiquinone-8.The major fatty acids were C18 : 1ω7c, iso-C16 : 0 and C16 : 0.The dominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content was 65 mol%. Based on the polyphasic taxonomic characterization, strains NH6-24T and Za3-11 are considered to represent a novel species of a novel genus, for which the name Sinimarinibacterium flocculans gen. nov., sp. nov. is proposed. The type strain of the type species is NH6-24T ( = CGMCC 1.10815T = JCM 17607T) and an additional strain is Za3-11 ( = CGMCC 1.10816 = JCM 17606).

Povalibacter uvarum gen. nov., sp. nov., a polyvinyl-alcohol-degrading bacterium isolated from grapes

Polyvinyl-alcohol-degrading bacteria were isolated from the fruit of a grape in Yokosuka, Japan. The isolated strain, Zumi 37(T), was a Gram-stain-negative, rod-shaped, motile, non-spore-forming and strictly aerobic chemo-organotroph, showing optimal growth at pH 7.5, 30 °C and 0.1% (w/v) NaCl. The major respiratory quinone was Q-8. The predominant fatty acids were iso-C(15 : 0), C(16 : 0) and C(16 : 1)ω7c. The major polyamines were homospermidine and putrescine. The predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content of the novel strain was 64.2 mol%. 16S rRNA gene sequence comparison revealed that strain Zumi 37(T) belongs to the family Sinobacteraceae within the class Gammaproteobacteria. Steroidobacter denitrificans DSM 18526(T) was the most closely related species with a validly published name, with 98.0% similarity based on 16S rRNA gene sequence comparison (and showed less than 87.5% sequence similarity to members of the genera Alkanibacter, Fontimonas, Hydrocarboniphaga, Nevskia and Solimonas with known 16S rRNA gene sequences). Phenotypes for growth under aerobic conditions and on complex media and major fatty acid composition, differed greatly from those of with comparatively high 16S rRNA gene sequence similarity. Based on phylogenetic, phenotypic and chemotaxonomic evidence, it is proposed that strain Zumi 37(T) represents a novel species in a new genus for which the name Povalibacter uvarum gen. nov., sp. nov. is proposed. The type strain of the type species is Zumi 37(T) ( = JCM 18749(T) = DSM 26723(T)).

The growth of Steroidobacter agariperforans sp. nov., a novel agar-degrading bacterium isolated from soil, is enhanced by the diffusible metabolites produced by bacteria belonging to Rhizobiales

An agar-degrading bacterium was isolated from soil collected in a vegetable cropping field. The growth of this isolate was enhanced by supplying culture supernatants of bacteria belonging to the order Rhizobiales. Phylogenetic analysis based on 16S rRNA gene sequences indicated the novel bacterium, strain KA5-B(T), belonged to the genus Steroidobacter in Gammaproteobacteria, but differed from its closest relative, Steroidobacter denitrificans FS(T), at the species level with 96.5% similarity. Strain KA5-B(T) was strictly aerobic, Gram-negative, non-motile, non-spore forming, and had a straight to slightly curved rod shape. Cytochrome oxidase and catalase activities were positive. The strain grew on media containing culture supernatants in a temperature range of 15-37°C and between pH 4.5 and 9.0, with optimal growth occurring at 30°C and pH 6.0-8.0. No growth occurred at 10 or 42°C or at NaCl concentrations more than 3% (w/v). The main cellular fatty acids were iso-C15:0, C16:1ω7c, and iso-C17:1ω9c. The main quinone was ubiquinone-8 and DNA G+C content was 62.9 mol%. In contrast, strain FS(T) was motile, did not grow on the agar plate, and its dominant cellular fatty acids were C15:0 and C17:1ω8c. Based on its phylogenetic and phenotypic properties, strain KA5-B(T) (JCM 18477(T) = KCTC 32107(T)) represents a novel species in genus Steroidobacter, for which the name Steroidobacter agariperforans sp. nov. is proposed.

Solimonas terrae sp. nov., isolated from soil

A Gram-stain-negative, aerobic, motile, rod-shaped bacterium, designated strain KIS83-12(T), was isolated from soil of Gaui island in the Taean region of South Korea. The strain grew at 15-33 °C (optimum, 28 °C), at pH 5.0-8.0 (optimum, pH 7.0). Growth did not occur in the presence of NaCl. The strain was catalase-negative and oxidase-positive. Phylogenetic analysis based on 16S rRNA gene sequences showed that KIS83-12(T) was most closely related to Solimonas soli DCY12(T) (96.9 %), Solimonas variicoloris MN28(T) (96.5 %), Solimonas flava CW-KD 4(T) (96.5 %) and Solimonas aquatica NAA16(T) (96.0 %), and formed a robust phyletic lineage with members of the genus Solimonas. The main isoprenoid quinone was Q-8. Major polar lipids included phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Fatty acids present in large and moderate amounts (>5.0 %) were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0, C16 : 1ω5c, summed feature 2 (iso-C16 : 1 I and/or C14 : 0 3-OH) and C12 : 0. The DNA G+C content was 67.9 mol%. On the basis of the taxonomic data obtained in this study, KIS83-12(T) represents a novel species of the genus Solimonas, for which the name Solimonas terrae sp. nov. is proposed, with KIS83-12(T) ( = KACC 16967(T) = DSM 27281(T)) as the type strain.

The family name Solimonadaceae Losey et al. 2013 is illegitimate, proposals to create the names ‘Sinobacter soli’ comb. nov. and ‘Sinobacter variicoloris’ contravene the Code, the family name Xanthomonadaceae Saddler and Bradbury 2005 and the order name Xanthomonadales Saddler and Bradbury 2005 are illegitimate and notes on the application of the family names Solibacteraceae Zhou et al. 2008, Nevskiaceae Henrici and Johnson 1935 (Approved Lists 1980) and Lysobacteraceae Christensen and Cook 1978 (Approved Lists 1980) and order name Lysobacteriales Christensen and Cook 1978 (Approved Lists 1980) with respect to the classification of the corresponding type genera Solibacter Zhou et al. 2008, Nevskia Famintzin 1892 (Approved Lists 1980) and Lysobacter Christensen and Cook 1978 (Approved Lists 1980) and importance of accurately expressing the link between a taxonomic name, its authors and the corresponding description/circumscription/emendation

In a recent publication the name Solimonadaceae Losey et al. 2013 has been proposed as a replacement name for the family name Sinobacteraceae Zhou et al. 2008. This course of action contravenes the current Code governing the nomenclature of prokaryotes, making Solimonadaceae Losey et al. 2013 an illegitimate name that neither has claim to priority nor can be used as a correct name. Closer examination of publications dealing with the taxonomy of members of the genera Solimonas and Sinobacter and the placement of these taxa at the rank of family and order reveal problems associated with the application of the family names Sinobacteraceae Zhou et al. 2008, Nevskiaceae Henrici and Johnson 1935 (Approved Lists 1980) and Lysobacteraceae Christensen and Cook 1978 (Approved Lists 1980) and the order names Lysobacterales Christensen and Cook 1978 (Approved Lists 1980) and Xanthomonadales Saddler and Bradbury 2005.