- Volume 73, Issue 4, 2023

A novel strain, designated as LRZ36T, was isolated from deep-sea sediment (from a depth of 5400 m) from the Mariana Trench. Cells of this strain are rod-shaped, Gram-stain-negative, strictly aerobic and non-motile. Phylogenetic analysis of LRZ36T based on 16S rRNA gene sequences revealed a lineage in the family Aurantimonadaceae but distinct from the most closely related species Aurantimonas marina CGMCC 1.17725T, ‘ Aurantimonas litoralis ’ KCTC 12094 and Aurantimonas coralicida DSM 14790T with sequence identities of 99.4 %, 98.0 and 97.9 %, respectively. The genome of LRZ36T was 3.8 Mbp in size with a DNA G+C content of 64.8 %, containing 3623 predicted coding genes. LRZ36T showed average nucleotide identity values of 89.8 %, 78.7 and 78.5 % and digital DNA–DNA hybridization values of 38.9 %, 21.7 and 21.6 % with A. marina CGMCC 1.17725T, ‘ A. litoralis ’ KCTC 12094 and A. coralicida DSM 14790T, respectively. The major respiratory quinone was ubiquinone-10 (Q-10), and the predominant fatty acids were C18 : 1ω7c (74.4 %) and C16 : 0 (12.1 %). The polar lipids in LRZ36T are diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylcholine, phosphatidylinositol mannoside, an unidentified aminophospholipid, three unidentified lipids, three unidentified phospholipids and two unidentified aminolipids. On the basis of genotypic and phenotypic evidence, LRZ36T represents a novel species of the genus Aurantimonas , for which the name Aurantimonas marianensis sp. nov. is proposed. The type strain is LRZ36T (= KCTC 92065T = GDMCC 1.2985T=MCCC 1K07227T).

Two Gram-stain-negative, facultatively anaerobic, motile, rod-shaped and flagellated marine bacteria, designated strains DBSS07T and ZSDZ65T, were isolated from the surface sediments of the Bohai sea and Qingdao coastal seawater, respectively. Phylogenetic analysis based on 16S rRNA genes, multilocus sequence analysis (MLSA), phylogenomic analysis of single-copy gene families and whole-genome data placed DBSS07T and ZSDZ65T within the genus Vibrio . DBSS07T was most closely related to Vibrio aestivus M22T, with 97.51 % sequence similarity, whereas ZSDZ65T was most closely related to Vibrio variabilis R-40492T with 97.58 % sequence similarity. DBSS07T grew with 1–7 % (w/v) NaCl (optimum 3 %), at 16–37 °C (optimum 28 °C) and at pH 6.0–9.0 (optimum pH 7.0); whereas ZSDZ65T grew with 1–5 % (w/v) NaCl (optimum 2 %), at 16–32 °C (optimum 28 °C) and at pH 6.0–9.0 (optimum pH 8.0). Both strains shared the same major fatty acid components (more than 10 % of total fatty acids) of summed feature 3 (C16 : 1ω7c or/and C16 : 1ω6c), with different proportions. The DNA G+C contents of DBSS07T and ZSDZ65T were 44.7 and 44.3 %, respectively. On the basis of the results of polyphasic analysis, DBSS07T and ZSDZ65T are considered to represent novel species within the genus Vibrio , for which the names V. paucivorans sp. nov. (type strain, DBSS07T = KCTC 82896T= MCCC 1K06284T) and V. qingdaonensis sp. nov. (type strain, ZSDZ65T = KCTC 82893T = MCCC 1K06289T) are proposed, respectively.

A taxonomic study was carried out on strain BGMRC 0090T, which was isolated from seawater. The isolate was a Gram-negative, aerobic, flagellated, rod-shaped bacterium with algicidal activity. Optimal growth was observed at 30 °C, pH 6.0 and with 2 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain BGMRC 0090T belonged to the genus Parvularcula , with highest sequence similarity to Parvularcula lutaonensis CC-MMS-1T (98.4 %). Average nucleotide identity, amino acid identity and digital DNA–DNA hybridization values between strain BGMRC 0090T and five strains of the genus Parvularcula with publicly available genomes were below 84.0, 69.2 and 21.4 %, respectively. The genome of strain BGMRC 0090T was 3.2 Mb with 64.8 mol% DNA G+C content and encoded 2905 predicted proteins, three rRNA, 42 tRNA and four ncRNA genes. Some algicidal biosynthesis-associated genes were detected in the genome. Strain BGMRC 0090T contained Q-10 as the major quinone. The predominant fatty acids were identified as summed feature 8 (C18 : 1ω7c/ω6c) and C16 : 0. Based on the polyphasic evidence presented in this paper, strain BGMRC 0090T is concluded to represent a novel species of the genus Parvularcula , for which the name Parvularcula maris sp. nov. is proposed. The type strain is BGMRC 0090T (= KCTC 92591T=MCCC 1K08100T).

A novel sulphate-reducing bacterium, strain SYKT, was isolated from a xenic culture of an anaerobic protist obtained from a sulphidogenic sediment of the saline Lake Hiruga in Fukui, Japan. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that SYKT clustered with the members of the genus Pseudodesulfovibrio . The closest relative of strain SYKT was Pseudodesulfovibrio sediminis SF6T, with 16S rRNA gene sequence identity of 97.43 %. Digital DNA–DNA hybridisation and average nucleotide identity values between SYKT and species of the genus Pseudodesulfovibrio fell below the respective thresholds for species delineation, indicating that SYKT represents a novel species of the genus Pseudodesulfovibrio . Cells measured 1.7–3.7×0.2–0.5 µm in size and were Gram-stain-negative, obligately anaerobic, motile by means of a single polar flagellum and had a curved rod or sigmoid shape. Cell growth was observed under saline conditions from pH 6.0 to 9.5 (optimum pH 8.0–9.0) and at a temperature of 10–30 °C (optimum 25 °C). SYKT used lactate, pyruvate, fumarate, formate and H2 as electron donors. It used sulphate, sulphite, thiosulphate and sulphur as terminal electron acceptors. Pyruvate and fumarate were fermented. Major cellular fatty acids were anteiso-C15 : 0, C16 : 0, anteiso-C17 : 1ω9c, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The DNA G+C content of SYKT was 49.4 mol%. On the basis of the the genetic and phenotypic features, SYKT was determined to represent a novel species of the genus Pseudodesulfovibrio for which the name Pseudodesulfovibrio nedwellii sp. nov. is proposed with type strain SYKT (=DSM 114958T=JCM 35746T).

Currently, the genus Paracoccus comprises 76 recognized species. Members of Paracoccus are mostly isolated from environmental, animal, and plant sources. This report describes and proposes a novel species of Paracoccus isolated from clinical specimens of the human ocular surface. We isolated two aerobic, Gram-stain-negative, non-spore-forming, coccoid or short rod-shaped, and non-motile strains (designated DK398T and DK608) from conjunctival sac swabs of two healthy volunteers. The results showed that the strains grew best under the conditions of 28°C, pH 7.0, and 1.0 % (w/v) NaCl. Sequence analysis based on the 16S rRNA gene showed that strains DK398T and DK608 were members of Paracoccus , most similar to Paracoccus laeviglucosivorans 43PT (98.54 and 98.62 %), Paracoccus litorisediminis GHD-05T (98.34 and 98.41 %), and Paracoccus limmosus NB88T (98.21 and 98.29 %). Phenotypic analysis showed that DK398T and DK608 were positive for catalase and oxidase, negative for producing N-acetyl-β-glucosaminic acid, arginine dihydrolase, and β-glucuronidase but positive for leucine arylamidase. The predominant isoprenoid quinone was Q-10, and the major polar lipids included phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, and an unidentified glycolipid. The major fatty acids (>10%) were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C16 : 0. The meso-diaminopimelic acid was found in the cell wall peptidoglycan of DK398T. The major cell wall sugars were ribose and galactose. Based on the results of phylogenetic analyses, low (<83.22 %) average nucleotide identity, digital DNA–DNA hybridization (<26.0%), chemotaxonomic analysis, and physiological properties, strain DK398T represents a novel species of the genus Paracoccus , for which the name Paracoccus shanxieyensis sp. nov. is proposed. The type strain is DK398T (=CGMCC 1.17227T=JCM 33719T).

Two Gram-stain-negative, facultative aerobic, catalase- and oxidase-positive, and non-motile rod bacteria, strains BLT and W38T, that were isolated from soil and freshwater, respectively, were taxonomically characterized. Both strains optimally grew at 30 °C and pH 7.0 in Reasoner's 2A medium and contained ubiquinone-8 as the sole respiratory quinone. As major fatty acids (>10 %), strain BLT contained iso-C15 : 0 and summed features 3 and 9 (comprising iso-C15 : 0 2-OH and/or C16 : 1  ω7c/ω6c and iso-C17 : 1  ω9c and/or C16 : 0 10-methyl, respectively), whereas strain W38T contained iso-C15 : 0, iso-C16 : 0 and summed feature 9. Diphosphatidylglycerol and phosphatidylmonomethylethanolamine as major polar lipids and phosphatidylethanolamine and phosphatidylglycerol as minor polar lipids were detected in both strains. The DNA G+C contents of strains BLT and W38T were 68.3 and 65.3 %, respectively. Phylogenetic analyses based on 16S rRNA gene and genome sequences revealed that strains BLT and W38T formed a tight phylogenetic lineage with Tahibacter species, and they shared 98.8 % 16S rRNA gene sequence similarity and 75.5 % average nucleotide identity (ANI) and 16.6 % digital DNA–DNA hybridization (dDDH) values, indicating that they are different species. Strains BLT and W38T were most closely related to Tahibacter caeni BUT-6T and Tahibacter aquaticus PYM5-11T with 97.7 and 98.0 % 16S rRNA gene sequence similarities, respectively. ANI and dDDH values between strain BLT and T. caeni BUT-6T and between strain W38T and T. aquaticus DSM 21667T were 78.5 and 21.6% and 75.3 and 21.0 %, respectively. Based on their phenotypic, chemotaxonomic and genomic properties, strains BLT and W38T represent two different novel species of the genus Tahibacter , for which the names Tahibacter soli sp. nov. and Tahibacter amnicola sp. nov. are proposed. The type strains of T. soli and T. amnicola are BLT (=KACC 22831T=JCM 35402T) and W38T (=KACC 22832T=JCM 35749T), respectively.

Three strains, TT30T, TT37T and L3T, were isolated from tidal flat samples. Cells were Gram-stain-negative, non-motile and rod shaped. Cells of strains TT30T and TT37T were able to grow in a medium containing 1.0–15.0 % (w/v) NaCl (optimum, 3.0 and 4.0 %, respectively), and cells of strain L3T was able to grow in a medium containing 1.0–10.0 % (w/v) NaCl (optimum, 1.0 %). Growth of the three strains was observed at pH 6.0–10.0 and at 10–40 °C. Strains TT30T, TT37T and L3T showed the highest similarity to Microbulbifer hydrolyticus DSM 11525T (97.7 %), M . yueqingensis CGMCC 1.10658T (98.0 %) and M. elongatus DSM 6810T (97.9 %), respectively. Results of phylogenetic analyses indicated that the three isolates represented two distinct lineages within the genus Microbulbifer . The DNA G+C contents of strains TT30T, TT37T and L3T were 61.3, 60.9 and 60.2%, respectively. The average nucleotide identity and in silico DNA–DNA hybridization values among strains TT30T, TT37T and L3T and the reference strains were 84.4–87.4 and 19.6–28.9 %, respectively. Differential phenotypic properties, chemotaxonomic differences, phylogenetic distinctiveness, together with the genomic data, demonstrated that strains TT30T, TT37 T and L3T represent novel species of the genus Microbulbifer , which are named Microbulbifer zhoushanensis sp. nov. (TT30T=KCTC 92167T=MCCC 1K07276T), Microbulbifer sediminum sp. nov. (TT37T=KCTC 92168T=MCCC 1K07277T) and Microbulbifer guangxiensis sp. nov. (L3T=KCTC 92165T=MCCC 1K07278T).

Members of the genus Novosphingobium were frequently isolated from polluted environments and possess great bioremediation potential. Here, three species, designated B2637T, B2580T and B1949T, were isolated from mangrove sediments and might represent novel species in the genus Novosphingobium based on a polyphasic taxonomy study. Phylogenomic analysis revealed that strains B2580T, B1949T and B2637T clustered with Novosphingobium naphthalenivorans NBRC 102051T, ‘ N. profundi ’ F72 and N. decolorationis 502str22T, respectively. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between isolates and their closely related species were less than 94 and 54 %, respectively, all below the threshold of species discrimination. The sizes of the genomes of isolates B2580T, B2637T and B1949T ranged from 4.4 to 4.6 Mb, containing 63.3–66.4 % G+C content. Analysis of their genomic sequences identified genes related to pesticide degradation, heavy-metal resistance, nitrogen fixation, antibiotic resistance and sulphur metabolism, revealing the biotechnology potential of these isolates. Except for B2637T, B1949T and B2580T were able to grow in the presence of quinalphos. Results from these polyphasic taxonomic analyses support the affiliation of these strains to three novel species within the genus Novosphingobium , for which we propose the name Novosphingobium album sp. nov. B2580T (=KCTC 72967T=MCCC 1K04555T), Novosphingobium organovorum sp. nov. B1949T (=KCTC 92158T=MCCC 1K03763T) and Novosphingobium mangrovi sp. nov. B2637T (KCTC 72969T=MCCC 1K04460T).

A Gram-stain-negative, rod-shaped, bright-orange coloured bacterium without flagellum, designated as strain GRR-S6-50T, was isolated from a tidal flat of Garorim bay, Taean-gun, Chungcheongbuk-do, Republic of Korea. Cells grew aerobically at 20–37 °C (optimum, 30 °C), pH 7.0–10.0 (optimum, pH 7.0) and with 1–5 % (w/v) NaCl (optimum, 3 %). The 16S rRNA gene sequence analysis demonstrated that strain GRR-S6-50T was closely related to Sphingomicrobium aestuariivivum AH-M8T with a sequence similarity of 97.80 % followed by Sphingomicrobium astaxanthinifaciens CC-AMO-30BT (97.44 %), Sphingomicrobium marinum CC- AMZ-30MT (97.16 %), Sphingomicrobium arenosum CAU 1457T (96.37 %), Sphingomicrobium flavum CC-AMZ-30NT (95.31 %) and Sphingomicrobium lutaoense CC-TBT-3T (95.23 %). The average nucleotide identity and digital DNA–DNA hybridization values with related strains ranged from 74.5 to 77.3% and 21.1 to 35.0 %, respectively. The G+C content of strain GRR-S6-50T was 63.30 mol%. The strain has ubiquinone-10 as the predominant respiratory quinone and the major fatty acids were C18 : 3  ω6c (54.57 %) and C17 : 1  ω6c (10.58 %). The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, three unidentified lipids and one glycolipid. On the basis of the results of phylogenetic, phenotypic and chemotaxonomic studies, strain GRR-S6-50T is regarded to represent a novel species within the genus Sphingomicrobium , for which the name Sphingomicrobium sediminis sp. nov. (KACC 22562T=KCTC 92123T=JCM 35084T) is proposed.

In the process of exploring the microbial diversity of pig farms, a Gram-stain-negative, aerobic, rod-shaped, non-spore-forming, non-motile bacterial strain, designated P2KT, was isolated from soil sample collected at a pig farm, Guangdong Province, PR China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain P2KT belonged to the genus Tahibacter , with the highest sequence similarity to Tahibacter aquaticus PYM5-11T (98.6%) and Tahibacter caeni BUT-6T (98.3 %). The genome size of strain P2KT was 6.0 Mb with a DNA G+C content of 68.3 mol%. Average nucleotide identity values between strain P2KT and the type strains of the genus Tahibacter were 81.1–81.6 %. The digital DNA–DNA hybridization values between P2KT and these relative species were 24.5–25.6%. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, an unknown aminolipids, two unknown lipids and three unknown phospholipids. The major respiratory quinone of strain P2KT was ubiquinone Q-8, and the main fatty acids (>10.0 % of total fatty acids) of strain P2KT were iso-C15:0, iso-C16:0 and summed feature 9 (C16:0 10-methyl and/or iso-C17:1 ω9c). Based on phenotypic and genotypic data, strain P2KT represents a novel species within the genus Tahibacter , for which the name Tahibacter harae sp. nov. is proposed, with the type strain P2KT (=GDMCC 1.3107T=JCM 35231T).

Gram-negative, motile, rod-shaped bacterial strains (designated 4F2T and Kf) were isolated from decaying tissues of various deciduous tree species. Phylogenetic analyses based on their 16S rRNA gene sequences showed that the novel isolates belong to the genus Brenneria and showed highest (98.3 %) sequence similarity to Brenneria goodwinii . Isolate 4F2T formed a separate branch on the phylogenetic tree based on concatenated sequences of four housekeeping genes or whole genome sequences, clearly separate from Brenneria goodwinii , suggesting that novel isolates should belong to a novel species. Orthologous average nucleotide identity scores and in silico DNA–DNA hybridization values between isolate 4F2T and type strains of other species in the genus Brenneria were less than 85 and 30 %, respectively, significantly lower than the species boundary cut-off values (95 and 70 %). A negative reaction for β-galactosidase, the ability to use dextrin and maltose as carbon sources, and an inability to use lactose are the main phenotypic characteristics that can be used to differentiate the novel isolates from B. goodwinii . Based on phenotypic and genotypic characteristics, isolates 4F2T and Kf belong to a novel species of the genus Brenneria , for which the name Brenneria bubanii sp. nov. is proposed. The type strain is 4F2T (=NCAIM B 02661T=LMG 32183T).

Four strains (NYNU 178247, NYNU 178251, DMKU-PAL160 and DMKU-PAL137) representing a novel yeast species were isolated from the external surfaces of rice and pineapple leaves collected in China and Thailand. Phylogenetic analysis based on the concatenated sequences of the internal transcribed spacer (ITS) regions and the D1/D2 domains of the large subunit rRNA gene revealed that the novel species belonged to the genus Spencerozyma. The D1/D2 sequence of the novel species differed from its closest relative, Spencerozyma acididurans SYSU-17T, by 3.2 % sequence divergence. The species also differed from Spencerozyma crocea CBS 2029T and Spencerozyma siamensis DMKU13-2T, by 3.0–6.9 % sequence divergence in the D1/D2 sequences out of 592 bp. In the ITS regions, the novel species displayed 19.8–29.2% sequence divergence from S. acididurans SYSU-17T, S. crocea CBS 2029T and S. siamensis DMKU13-2T out of 655 bp. Furthermore, the novel species could also be differentiated from the closely related species by some physiological characteristics. The species name of Spencerozyma pingqiaoensis sp. nov. (Holotype CBS 15238, Mycobank MB 844734) is proposed to accommodate these four strains.

Sixteen yeast isolates representing two novel species of the genus Sugiyamaella were obtained from passalid beetles, their galleries and rotting wood collected in three sites of Amazonian Forest in Brazil. Sequence analyses of the ITS-5.8S region and the D1/D2 domains of the large subunit rRNA gene showed that the first species, described here as Sugiyamaella amazoniana f. a., sp. nov. (holotype CBS 18112, MycoBank 847461) is phylogenetically related to S. bonitensis with these species differing by 37 nucleotide substitutions and six gaps in D1/D2 sequences. S. amazoniana is represented by nine isolates obtained from the guts of the passalid beetles Popilius marginatus, Veturius magdalenae, Veturius sinuosus and Spasalus aquinoi, a beetle gallery and rotting wood. The second species, Sugiyamaella bielyi f. a., sp. nov. (holotype CBS 18148, MycoBank 847463), is most phylogenetically related to several undescribed Sugiyamaella species. S. bielyi is described based on seven isolates obtained from the guts of V. magdalenae and V. sinuosus, a beetle gallery and rotting wood. Both species appear to be associated with passalid beetles and their ecological niches in Amazonian biome.

The prokaryotic generic names Gramella Nedashkovskaya et al. 2005, Melitea Urios et al. 2008 and Nicolia Oliphant et al. 2022 are illegitimate because they are later homonyms of the names Gramella Kozur 1971, a genus of fossil ostracods, Melitea Péron and Lesueur 1810 (Scyphozoa, Cnidaria), Melitea Lamouroux 1812 (Anthozoa, Cnidaria), Nicolia Unger 1842, an extinct plant genus, and Nicolia Gibson-Smith and Gibson-Smith 1979 (Bivalvia, Mollusca), respectively (Principle 2 and Rule 51b(4) of the International Code of Nomenclature of Prokaryotes). For Gramella , we therefore propose the replacement generic name Christiangramia with type species Christiangramia echinicola comb. nov. and we propose the reclassification of 18 other species of Gramella in the genus Christiangramia as new combinations. In addition, we propose the replacement generic names Neomelitea with type species Neomelitea salexigens comb. nov. and Nicoliella with type species Nicoliella spurrieriana comb. nov.

Organisms classified as members of the genus Paramecium belong to the best-known group of single-celled eukaryotes. Nevertheless, the phylogeny within the genus Paramecium has been discussed and revisited in recent decades and remains partly unresolved. By applying an RNA sequence–structure approach, we attempt to increase accuracy and robustness of phylogenetic trees. For each individual 18S and internal transcribed spacer 2 (ITS2) sequence, a putative secondary structure was predicted through homology modelling. While searching for a structural template, we found, in contrast to the available literature, that the ITS2 molecule consists of three helices in members of the genus Paramecium and four helices in members of the genus Tetrahymena. Two sequencestructure neighbor-joining overall trees were reconstructed with (1) more than 400 taxa (ITS2) and (2) more than 200 taxa (18S). For smaller subsets, neighbor-joining, maximum-parsimony, and maximum-likelihood analyses were executed using sequence–structure information simultaneously. Based on a combined data set (ITS2+18S rDNA) a well-supported tree was reconstructed with bootstrap values over 50 in at least one of the applied analyses. Our results are in general agreement with those published in the available literature based on multi-gene analyses. Our study supports the simultaneous use of sequence–structure data to reconstruct accurate and robust phylogenetic trees.