Genome-based analysis of the family Paracoccaceae and description of Ostreiculturibacter nitratireducens gen. nov., sp. nov., isolated from an oyster farm on a tidal flat.

Two bacterial strains, designated FR2A1T and MT2-5-38, were isolated from the surface sediments of an oyster farm on a tidal flat in Quanzhou Bay, China. Both strains were Gram-stain-negative, rod-shaped, aerobic, catalase-positive, and oxidase-positive. The 16S rRNA gene sequences of the two strains were 100% identical and had the highest similarity (97.1%) with Phaeovulum vinaykumarii JA123T. The average nucleotide identity (ANI) value and digital DNA-DNA hybridization (DDH) value indicated that the two strains belonged to a single species. Gene annotation revealed that the two strains contained a gene cluster for nitrate reduction and a gene cluster for sulfur oxidation, indicating a possible role in N and S cycling in the tidal flat sediment. The phylogeny inferred from the 16S rRNA gene and 120 conserved proteins indicated that the two strains formed a distinct monophyletic clade within the family Paracoccaceae. The respiratory quinone was Q-10. The major fatty acids consisted of summed feature 8 (C18:1ω7c and/or C18:1ω6c) and C18:0. The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, and several unidentified phospholipids. Based on the above characteristics, strains FR2A1T and MT2-5-38 represent a novel genus and a novel species, for which we propose the name Ostreiculturibacter nitratireducens gen. nov., sp. nov. The type strain is FR2A1T (=MCCC 1K08809T = KCTC 8317T). Phylogenomic analysis of 1,606 high-quality genomes of the family Paracoccaceae, including type strains, non-type strains, and uncultivated bacteria, was performed using the Genome Taxonomic Database Toolkit (GTDB-Tk), and the average amino acid identity (AAI) value of the phylogenetic clade was estimated. We found that 35 species of the family Paracoccaceae needed re-classification, and an AAI value of 70% was chosen as the genus boundary within the family Paracoccaceae.

Cycloheptylprodigiosin from marine bacterium Spartinivicinus ruber MCCC 1K03745T induces a novel form of cell death characterized by Golgi disruption and enhanced secretion of cathepsin D in non-small cell lung cancer cell lines.

Prodiginines have been studied extensively for their anticancer activity, however, the majority of the research has focused on prodigiosin. In this study, cycloheptylprodigiosin (S-1) is extracted from marine bacterium Spartinivicinus ruber MCCC 1K03745T, and its anticancer property was investigated. It exhibits remarkable cytotoxicity against a panel of human lung cancer cell lines, with the IC50 values ranging from 84.89 nM to 661.2 nM. After 6 h of treatment, S-1 gradually accumulates on mitochondria and lysosomes. While lower doses of S-1 induce cell cycle arrest, treatment with higher doses results in cell death in apoptotic independent manner in both NCI-H1299 and NCI-H460 cell lines. Interestingly, treatment with S-1 leads to the accumulation of LC3B-II via pathways that vary among different cell lines. In addition to its role as an autophagy inhibitor, S-1 also promotes autophagy initiation as demonstrated by the increment of EGFP fragment in the EGFP-LC3 degradation assay, however, inhibition of autophagy does not rescue cells from death induced by S-1. Mechanistically, S-1 impairs autophagic flux through disrupting acidic lysosomal pH and blocking the maturation of cathepsin D. Moreover, treatment with S-1 enhanced secretion of both pro- and mature forms of cathepsin D, coincident with disintegration of trans-Golgi network. Interestingly, S-1 does not induce ferroptosis, pyroptosis or necroptosis in NCI-H1299 cells. However, treatment of NCI-H460 cells with S-1 induces methuosis, which can be suppressed by Rac1 inhibitor EHT 1864. Our data demonstrate that S-1 is an effective anticancer agent with potential therapeutic application.

Mangrovimonas aestuarii sp. nov., isolated from tidal flat sediment.

A Gram-stain-negative, rod-shaped and light yellow-pigmented strain designated MBT5T was isolated from tidal flat sediment of an oyster farming area in Quanzhou Bay, PR China. Catalase activity and oxidase activity were positive. Flexirubin-type pigment was absent. Growth was observed at 10-40 °C (optimum, 35 °C), pH 6-9 (optimum, pH 7), and with 1-7 % NaCl (optimum, 2 %, w/v). The 16S rRNA gene of strain MBT5T had maximum sequence similarity values with Meridianimaribacter flavus NH57NT, Mangrovimonas yunxiaonensis LYYY01T and Mangrovimonas futianensis AS18T of 95.6, 95.4 and 94.9 %, respectively. Phylogenetic analysis based on 16S rRNA gene sequences and 120 conserved concatenated proteins indicated that strain MBT5T was affiliated to the genus Mangrovimonas and formed a distinct monophyletic branch. The digital DNA-DNA hybridization, average nucleotide identity and average amino acid identity values between strain MBT5T and the type strains of Mangrovimonas were estimated to be 17.3-18.7 %, 70.9-71.5 % and 66.4-68.2 %, respectively. The respiratory quinone was menaquinone-6. The major fatty acids were iso-C15 : 0 and iso-C15 : 1 G. The draft genome size was 2 952 053 bp with a DNA G+C content of 36.5 %. Based on phenotypic, physiological, phylogenetic and genomic data, together with chemotaxonomic characteristics, strain MBT5T represents a novel species, for which the name Mangrovimonas aestuarii sp. nov. is proposed. The type strain is MBT5T (=MCCC 1K06186T=KCTC 92888T=GDMCC 1.3851T).

Coraliomargarita parva sp. nov., isolated from mangrove sediment and genome-based analysis of the class Opitutae revealed five novel families: Coraliomargaritaceae fam. nov., Pelagicoccaceae fam. nov., Cerasicoccaeae fam. nov., Oceanipulchritudinaceae fam. nov., and Alterococcaeae fam. nov.

Members of the class Opitutae are widely distributed in various environments such as rice paddy soil, freshwater lakes, seawater, marine sediment, and invertebrate digestive tracts. The class currently consists of two orders, Opitutales and Puniceicoccales, represented by the families Opitutaceae and Puniceicoccaceae, respectively, which are primarily delineated on the basis of 16S rRNA gene sequences and limited phenotypic characterizations of a few type strains. The scarcity of 16S rRNA gene and genome sequences generated from the type strains of the class Opitutae constrained our understanding of the ecological distribution and adequate resolution of its taxonomy. Here, an Opitutae strain designated WMMB3T, isolated from a mangrove sediment, was subjected to taxonomic characterization. The 16S rRNA gene of strain WMMB3T shared high sequence similarities with Coraliomargarita akajimensis DSM 45221T and C. sinensis WN38T of 96.1 and 95.9%, respectively. Phylogenetic analysis suggested that strain WMMB3T formed a monophyletic branch affiliated to the genus Coraliomargarita. The average nucleotide identity (ANI) values, digital DNA-DNA hybridization (dDDH) values and average amino acid identity (AAI) values of strain WMMB3T compared between Coraliomargarita members were 71.8-72.5, 20.7, and 68.2-68.7%, respectively, indicating that strain WMMB3T represented a novel species of Coraliomargarita. The genome of strain WMMB3T was 4.5 Mbp with a DNA G + C content of 56.0%. The respiratory quinone was menaquinone-7. The major fatty acids were iso-C14:0, and C18:1ω9c. Based on genomic, phenotypic, and chemotaxonomic characterizations, strain WMMB3T represents a novel species, and Coraliomargarita parva sp. nov. is proposed. Additionally, the phylogenomic analysis of more than 500 genomes of the class Opitutae, encompassing a majority of uncultivated bacteria and a few type strains, was performed using the Genome Taxonomic Database toolkit (GTDB-Tk) to present adequate resolution of the taxonomy. Combined with 16S rRNA gene sequence phylogeny and genomic relatedness, five novel families retrieved mainly from marine habitats were proposed: Coraliomargaritaceae fam. nov., Pelagicoccaceae fam. nov., Cerasicoccaeae fam. nov., Oceanipulchritudinaceae fam. nov., and Alterococcaeae fam. nov. AAI values of 58-60% could be considered as the boundary to delineate families of the class Opitutae. This study provided a new taxonomic framework of the class Opitutae based on the genomic data.

Paracrocinitomix mangrovi gen. nov., sp. nov., isolated from a mangrove sediment: proposal of two new families, Phaeocystidibacteraceae fam. nov. and Owenweeksiaceae fam. nov., and emended description of the family Schleiferiaceae.

A Gram-stain-negative and short rod-shaped bacterial strain designated GM2-3-6-6T was obtained from a mangrove sediment. Cells were light yellow-pigmented, catalase-positive and oxidase-positive. Carotenoid pigment was produced. Phylogeny of the 16S rRNA gene showed that strain GM2-3-6-6T was affiliated to the family Crocinitomicaceae, sharing maximum sequence similarities with Crocinitomix algicola 0182T, C. catalasitica IFO 15977T, and Putridiphycobacter roseus SM1701T of 93.8%, 93.6%, and 92.5%, respectively. The average nucleotide identity values, digital DNA-DNA hybridization estimates and average amino acid identity values between strain GM2-3-6-6T and the three close relatives were 68.6-68.8%, 18.5-19.2%, and 59.0-62.3%, respectively. The complete circular genome of strain GM2-3-6-6T was 4,365,762 bp in length with a DNA G + C content of 35.0%. The respiratory quinone was MK-7. The major polar lipids consisted of phosphatidylethanolamine, two unidentified phospholipids, one unidentified aminoglycolipid, one unidentified aminolipid and four other unidentified lipids. The major fatty acids were iso-C15:0, iso-C15:1 G, summed feature 3 (C16:1ω7c and/or C16:1ω6c), and iso-C17:0 3-OH. Based on genomic, phenotypic, and chemotaxonomic characterizations, strain GM2-3-6-6T represents a novel species of a novel genus, for which the name Paracrocinitomix mangrovi gen. nov., sp. nov. is proposed. The type strain is GM2-3-6-6T (= MCCC 1K04831T = KCTC 82931T). Additionally, phylogenomic analysis of the type strains of the family Schleiferiaceae and family Cryomorphaceae related members including uncultivated bacteria, was performed using the Genome Taxonomic Database toolkit (GTDB-Tk). Based on 16S rRNA gene phylogeny and genomic features, two novel families, Phaeocystidibacteraceae fam. nov. and Owenweeksiaceae fam. nov. are proposed. An emended description of the family Schleiferiaceae is also proposed.

Portibacter marinus sp. nov., isolated from the sediment on the surface of plastics and proposal of a novel genus Neolewinella gen. nov. based on the genome-based phylogeny of the family Lewinellaceae.

A Gram-stain-negative, rod-shaped and orange-pigmented bacterial strain designated 10MBP4-2-1T was isolated from the sediment on the surface of a plastic straw collected from oyster-farming areas in Quanzhou Bay, PR China. Catalase activity and oxidase activity were positive. Flexirubin-type pigment was absent. The 16S rRNA gene of strain 10MBP4-2-1T showed highest sequence similarity to Portibacter lacus YM8-076T of 98.3 %. Phylogenetic analysis based on 16S rRNA gene sequences and 120 conserved concatenated proteins indicated that strain 10MBP4-2-1T was affiliated to the genus Portibacter and formed a monophyletic clade with P. lacus YM8-076T. The digital DNA-DNA hybridization, average nucleotide identity and average amino acid identity values between strain 10MBP4-2-1T and P. lacus YM8-076T were estimated to be 17.7, 70.4 and 70.3 %, respectively. The respiratory quinone was menaquinone 7. The major fatty acid composition was iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c). The draft genome size was 5 191 941 bp with DNA G+C content of 39.2 %. Based on phylogenetic analyses and whole genomic comparisons, strain 10MBP4-2-1T represents a novel species, for which the name Portibacter marinus sp. nov. is proposed. The type strain is 10MBP4-2-1T (=MCCC 1K07073T=KCTC 92101T). Additionally, phylogeny and whole genomic comparison of the family Lewinellaceae placed Lewinella cohaerens and the remaining Lewinella (currently comprising 11 species) in two clearly distinguishable clades recognized at the genus level. Thus, a novel genus named Neolewinella gen. nov. is proposed to accommodate the 11 species. Our study provides a taxonomic framework for the family Lewinellaceae based on genomic data.

Description of Aestuariivivens marinum sp. nov., Aestuariivivens sediminis sp. nov. and Aestuariivivens sediminicola sp. nov., three new species isolated from the upper layer of tidal flat sediment.

Nine bacterial strains designated MT3-5-12T, MT3-5-27, MTV1-9, S-DT1-15T, S-DT1-34, MTV5-3T, MTV4-17, MTV5-12 and MTV5-13 were isolated from the upper layer (1-5 cm in depth) of tidal flat sediment in Quanzhou Bay, China. The 16S rRNA gene of these strains shared maximum sequence similarities with Aestuariivivens insulae KCTC 42350T of 94.9-97.1%. Phylogenetic analyses based on 16S rRNA gene sequences and 120 conserved concatenated proteins placed these strains in three novel phylogenetic clades affiliated to the genus Aestuariivivens of the family Flavobacteriaceae. Strains MT3-5-12T, MT3-5-27 and MTV1-9 were phylogenetically close to A. insulae KCTC 42350T. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strains MT3-5-12Tand MTV1-9 and A. insulae KCTC 42350T were estimated to be 78.5-78.7% and 22.5%, respectively. Strains S-DT1-15T and S-DT1-34 formed a distinctly separated clade from A. insulae KCTC 42350T. The ANI and dDDH values between strains S-DT1-15T and S-DT1-34 and A. insulae KCTC 42350T were 76.3-76.4% and 20.4-20.5%, respectively. The other four strains MTV5-3T, MTV4-17, MTV5-12 and MTV5-13, formed a third novel clade, distinctly separated from A. insulae KCTC 42350T. The ANI and dDDH values between strains MTV5-3T and MTV4-17 and A. insulae KCTC 42350T were 74.7% and 19.1-19.2%, respectively. The phylogenetic analyses and whole genomic comparisons, combined with phenotypic and chemotaxonomic features, strongly supported the nine strains could be classified as three novel species within the genus Aestuariivivens, for which the names Aestuariivivens marinum sp. nov. MT3-5-12T, Aestuariivivens sediminis sp. nov. S-DT1-15T, and Aestuariivivens sediminicola sp. nov. MTV5-3T are proposed.

Genome-based taxonomic rearrangement of Oceanobacter-related bacteria including the description of Thalassolituus hydrocarbonoclasticus sp. nov. and Thalassolituus pacificus sp. nov. and emended description of the genus Thalassolituus.

Oceanobacter-related bacteria (ORB) are a group of oligotrophic marine bacteria play an underappreciated role in carbon cycling. They have been frequently described as one of the dominant bacterial groups with a wide distribution in coastal and deep seawater of global oceans. To clarify their taxonomic affiliation in relation to alkane utilization, phylogenomic and comparative genomics analyses were performed based on currently available genomes from GenBank and four newly isolated strains, in addition to phenotypic and chemotaxonomic characteristics. Consistently, phylogenomic analysis robustly separated them into two groups, which are accordingly hydrocarbon-degrading (HD, Thalassolituus and Oleibacter) and non-HD (NHD, Oceanobacter). In addition, the two groups can also be readily distinguished by several polyphasic taxonomic characteristics. Furthermore, both AAI and POCP genomic indices within the HD group support the conclusion that the members of the genus Oleibacter should be transferred into the genus Thalassolituus. Moreover, HD and NHD bacteria differed significantly in terms of genome size, G + C content and genes involved in alkane utilization. All HD bacteria contain the key gene alkB encoding an alkane monooxygenase, which can be used as a marker gene to distinguish the members of closely related genera Oceanobacter and Thalassolituus. Pangenome analysis revealed that the larger accessory genome may endow Thalassolituus with the flexibility to cope with the dynamics of marine environments and thrive therein, although they possess smaller pan, core- and unique-genomes than Oceanobacter. Within the HD group, twelve species were clearly distinguished from each other by both dDDH and ANI genomic indices, including two novel species represented by the newly isolated strains alknpb1M-1 T and 59MF3M-4 T , for which the names Thalassolituus hydrocarbonoclasticus sp. nov. and Thalassolituus pacificus sp. nov. are proposed. Collectively, these findings build a phylogenetic framework for the ORB and contribute to understanding of their role in marine carbon cycling.

Nitrogeniibacter aestuarii sp. nov., a Novel Nitrogen-Fixing Bacterium Affiliated to the Family Zoogloeaceae and Phylogeny of the Family Zoogloeaceae Revisited.

Members of the family Zoogloeaceae within the order Rhodocyclales are found to play vital roles in terrestrial and aquatic ecosystems by participating in biofloc formation in activated sludge, polycyclic aromatic hydrocarbon degradation, and nitrogen metabolism, such as denitrification and nitrogen fixation. Here, two bacterial strains designated H1-1-2AT and ZN11-R3-1 affiliated to the family Zoogloeaceae were isolated from coastal wetland habitats. The 16S rRNA gene sequences of the two strains were 100% identical and had maximum similarity with Nitrogeniibacter mangrovi M9-3-2T of 98.4% and ≤94.5% with other species. Phylogenetic analysis suggested that the two strains belonged to a single species and formed a novel monophyletic branch affiliated to the genus Nitrogeniibacter. The average nucleotide identity (ANI) value and digital DNA-DNA hybridization (dDDH) estimate between the two strains and N. mangrovi M9-3-2T were 78.5-78.7% and 21.4-21.6%, respectively, indicating that the two strains represent a novel species. The genomes of strain H1-1-2AT (complete genome) and ZN11-R3-1 (draft genome) were 4.7Mbp in length encoding ~4,360 functional genes. The DNA G+C content was 62.7%. Nitrogen fixation genes were found in the two strains, which were responsible for the growth on nitrogen-free medium, whereas denitrification genes found in N. mangrovi M9-3-2T were absent in the two strains. The respiratory quinone was ubiquinone-8. The major polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, and aminophospholipid. The major fatty acids were summed feature 3 (C16:1 ω7c and C16:1 ω6c), C16:0, C12:0, and C10:0 3-OH. Based on genomic, phenotypic, and chemotaxonomic characterizations, strains H1-1-2AT and ZN11-R3-1 represent a novel species of the genus Nitrogeniibacter, for which the name Nitrogeniibacter aestuarii sp. nov. is proposed. The type strain is H1-1-2AT (=MCCC 1K04284T=KCTC 82672T), and additional strain is ZN11-R3-1 (=MCCC 1A17971=KCTC 82671). Additionally, phylogenomic analysis of the members of the family Zoogloeaceae including type strains and uncultivated bacteria was performed, using the Genome Taxonomic Database toolkit (GTDB-Tk). Combined with the 16S rRNA gene phylogeny, four novel genera, Parazoarcus gen. nov., Pseudazoarcus gen. nov., Pseudothauera gen. nov., and Cognatazoarcus gen. nov., were proposed. This study provided new insights to the taxonomy of the family Zoogloeaceae.

Aegicerativicinus sediminis gen. nov., sp. nov., a novel carotenoid-producing marine bacterium in the family Flavobacteriaceae.

A novel bright-yellow pigmented bacterial strain SM2-FT was isolated from a mangrove sediment collected at the mangrove coast of Luoyang estuary, Quanzhou, China. Strain SM2-FT was Gram-stain-negative, catalase-weak positive, oxidase-positive, rod-shaped, non-flagellated and non-motile. Growth of strain SM2-FT was observed at 20-40 °C (optimum, 30 °C), pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 1.0-4.0% NaCl (optimum, 2.0% NaCl). Flexirubin-pigment was absent, and carotenoid-pigment was present. Phylogenetic analysis of 16S rRNA gene sequence placed strain SM2-FT into the family Flavobacteriaceae and shared the maximum sequence similarity with Aequorivita soesokkakensis RSSK-12 T of 92.5%. Whole genomic comparison between strain SM2-FT and close relatives suggested a novel species of a novel genus. The predominant quinone of strain SM2-FT was menaquinone (MK)-6. The major fatty acids (> 10%) comprised iso-C15:1 G (32.4%) and iso-C15:0 (29.1%). The polar lipid profile consisted of phosphatidylethanolamine, two unidentified aminolipids and four unidentified lipids. The complete genome size was 4,094,245 bp with DNA G + C content of 36.0 mol%. Based on the data of polyphasic study, strain SM2-FT was considered to represent a novel species of a novel genus, for which the name Aegicerativicinus sediminis gen. nov., sp. nov., was proposed. The type strain was SM2-FT (= MCCC 1K04383T = KCTC 82361 T).

Spartinivicinus ruber gen. nov., sp. nov., a Novel Marine Gammaproteobacterium Producing Heptylprodigiosin and Cycloheptylprodigiosin as Major Red Pigments.

The red pigment prodiginines are identified as bacterial secondary metabolites and display a wide range of bioactive properties. Here, a novel rose-red pigmented bacterium, designated strain S2-4-1HT, was isolated from coastal sediment of cordgrass Spartina alterniflora. Interestingly, it simultaneously produced heptylprodigiosin (C22H29N3O) and cycloheptylprodigiosin (C22H27N3O) as major red pigments, of which their chemical structures were established by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR). Bioactive assays revealed that both heptylprodigiosin and cycloheptylprodigiosin had antibacterial and antifungal activities, and notably, cycloheptylprodigiosin showed stronger bioactivity than heptylprodigiosin. The complete genome of strain S2-4-1HT was determined to be 6,687,090 bp in length with a G + C content of 40.13 mol%, including a circular chromosome with a size of 6,361,125 bp and three plasmids with a size of 141,078, 102,423, and 82,464 bp, respectively. The biosynthetic gene cluster of two red pigments was predicted on a ∼41-kb gene fragment organized on the chromosome and displayed highly conserved features compared to several gammaproteobacterial species encoding the homologous genes. Finally, based on phenotypic, genotypic, and chemotaxonomic characteristics, strain S2-4-1HT represented a novel genus-level species named Spartinivicinus ruber gen. nov., sp. nov. (type strain S2-4-1HT = MCCC 1K03745T = KCTC 72148T). Our study provided a novel bacterial source and novel prodigiosin analogs as promising pharmaceuticals in biotechnological application.

Description of Maribellus sediminis sp. nov., a marine nitrogen-fixing bacterium isolated from sediment of cordgrass and mangrove.

Two marine bacterial strains designated Y2-1-60T and GM1-28 were isolated from sediments of cordgrass and mangrove along the Luoyang estuary in Quanzhou Bay, China, respectively. Both strains were Gram-staining-negative, straight rod-shaped, non-flagellum, facultatively anaerobic, nitrogen-fixing, and did not contain carotenoid pigment. Catalase activities were found to be weak positive and oxidase activities negative. The 16S rRNA gene sequences of the two strains were identical and had maximum similarity of 98.0% with Maribellus luteus XSD2T, and of <94.5% with other species. ANI value (96.9%) and DDH estimate (71.5%) between the two strains supported that they belonged to the same species. ANI value and DDH estimate between the two strains and M. luteus XSD2T was 74.3% and 19.4%, respectively, indicating that they represent a novel species. Phylogenetic analysis based on 16S rRNA gene and phylogenomic analysis indicated that strains Y2-1-60T and GM1-28 formed a monophyletic branch within the genus Maribellus. The respiratory quinone was menaquinone MK-7. The major fatty acid (>10%) consisted of iso-C15:0, and iso-C17:0 3-OH. The polar lipids consisted of phosphatidylethanolamine and several unidentified lipids. The genomic G+C contents were 41.9-42.0mol%. Gene annotation revealed that strains Y2-1-60T and GM1-28 contained a set of nif gene cluster (nifHDKENB) responsible for nitrogen fixation. Based on the above characteristics, strains Y2-1-60T and GM1-28 represent a novel species within the genus Maribellus. Thus, Maribellus sediminis sp. nov. is proposed with type strain Y2-1-60T (=MCCC 1K04285T=KCTC 72884T), isolated from cordgrass sediment and strain GM1-28 (=MCCC 1K04384=KCTC 72880), isolated from mangrove sediment.

Draconibacterium mangrovi sp. nov., isolated from mangrove sediment.

A marine bacterial strain, designated GM2-18T, was isolated from mangrove sediment sampled at Luoyang River estuary, Quanzhou, PR China. Cells were Gram-stain-negative, slightly curved long rod-shaped and facultatively anaerobic with no flagellum. Catalase activity was found to be weak-positive and oxidase-positive. It had no ability to degrade or hydrolyse substrates including skimmed milk, cellulose, starch and Tweens (40, 60 and 80). The 16S rRNA gene sequence of strain GM2-18T had maximum similarity values to 'Draconibacterium filum' F2T, Draconibacterium sediminis JN14CK-3T and Draconibacterium orientale FH5T of 98.0, 97.8 and 97.4 %, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain GM2-18T was affiliated to the genus Draconibacterium and formed a clade with an uncultured bacterium clone identified from mangrove environment. Average nucleotide identity values and DNA-DNA hybridization estimates of strain GM2-18T compared to its Draconibacterium relatives strongly supported that it belonged to a new species. The respiratory quinone was menaquinone MK-7. The major fatty acids (>10 %) consisted of iso-C15 : 0, anteiso-C15 : 0 and C17 : 1 ω6c. The polar lipids were phosphatidylethanolamine, a phospholipid and several unidentified lipids. The genomic size of strain GM2-18T was 5.9 Mb and the G+C content was 40.8 mol%. Gene prediction and annotation of strain GM2-18T indicated that there was a nitrogen-fixing gene cluster encoding nitrogenase molybdenum-iron protein and related proteins responsible for nitrogen fixation. Based on the above characteristics, strain GM2-18T represents a novel species within the genus Draconibacterium. Thus, Draconibacterium mangrovi sp. nov. is proposed with type strain GM2-18T (=MCCC 1K04382T=KCTC 72879T), isolated from mangrove sediment.

Croceicoccus sediminis sp. nov., isolated from coastal sediment.

A Gram-stain-negative, cocci or short rod-shaped, yellow-pigmented bacterium, designated strain S2-4-2T, was isolated from coastal sediment of Spartina alterniflora in Quanzhou Bay, PR China. Growth was observed at 15-40 °C (optimum, 30 °C) and pH 6.0-8.0 (optimum, pH 7.0). Strain S2-4-2T tolerated 0-10 % NaCl (optimum, 1 %). The 16S rRNA gene of strain S2-4-2T showed highest sequence similarity to Croceicoccus pelagius Ery9T (98.2 %), followed by Croceicoccus naphthovorans PQ-2T, Croceicoccus marinus E4A9T and Croceicoccus mobilis Ery22T (97.6%, 96.3 and 96.3 %, respectively). Phylogenetic analysis based on 16S rRNA gene sequences and phylogenomic analysis based on 92 up-to-date bacterial core gene sets indicated that strain S2-4-2T forms a distinct monophyletic branch affiliated to the genus Croceicoccus. The average nucleotide identity value between strain S2-4-2T and its close relatives were estimated to be 74.8-85.7 %. The respiratory quinone was found to be Q-10. The predominant fatty acids (>10 %) were identified as summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and summed feature 3 (C16 : 1ω7c and C16 : 1ω6c). The polar lipids were identified as phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and an unidentified phospholipid. The draft genome size of strain S2-4-2T was 3.5 Mb with a genomic G+C content of 63.0 mol%. Based on these results, strain S2-4-2T is concluded to represent a novel species within the genus Croceicoccus, for which the name Croceicoccus sediminis sp. nov. is proposed with the type strain S2-4-2T (=MCCC 1K03706T=KCTC 72146T).

Pleionea sediminis sp. nov., isolated from coastal sediment and emendation of the description of the genus Pleionea.

A Gram-stain-negative, rod-shaped and non-motile bacterium, designated strain S1-5-21T, was isolated from coastal sediment in Quanzhou Bay, PR China, and subjected to taxonomic characterization. Growth of strain S1-5-21T was observed at 15-40 °C (optimum, 30-35 °C), NaCl tolerance of 0.5-10 % NaCl (w/v; optimum, 1 %), and pH range of 5-8 (optimum, pH 7). Catalase activity and oxidase activity were found to be positive. The nearly complete 16S rRNA gene sequence of strain S1-5-21T shows maximum sequence similarity to Pleionea mediterranea MOLA115T (95.7 %), followed by Kangiella chungangensis CAU 1040T (90.4 %) and Aliikangiella marina GYP-15T (90.1 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S1-5-21T forms a distinct monophyletic branch affiliated to the genus Pleionea. The ANI value between strain S1-5-21T and close relative P. mediterranea MOLA115T was estimated to be 70.8 %. The respiratory quinone was found to be Q-8. The predominant fatty acids (>10 %) were identified as iso-C15 : 0, summed feature 9 (iso-C17 : 1 ω9c and/or C16 : 0 10-methyl) and iso-C16 : 0. The polar lipids were identified as phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two aminolipids, three phospholipids and five unidentified polar lipids. The draft genome size of strain S1-5-21T is 5.2 Mb with genomic G+C content of 40.1 mol%. Based on these results, strain S1-5-21T is concluded to represent a novel species within the genus Pleionea, for which the name Pleioneasediminis sp. nov. is proposed with the type strain S1-5-21T (=MCCC 1K03814T=KCTC 72149T).

Cohaesibacter intestini sp. nov., isolated from the intestine of abalone, Haliotis discus hannai.

A Gram-stain-negative, rod-shaped and facultative anaerobic strain named YE-B6T was isolated from the intestine of abalone, Haliotis discus hannai. The reactions of oxidase and catalase were both positive. Strain YE-B6T could grow at 10-37 °C (optimum, 28-33 °C), at pH 7-9 (optimum, pH 7) and in salinity of 0-8 % NaCl (w/v; optimum, 2 %). The 16S rRNA gene sequence of strain YE-B6T had maximum sequence similarities to Cohaesibacter celericrescens H1304T (98.0 %), Cohaesibacter marisflavi DQHS21T (97.4 %), Cohaesibacter haloalkalitolerans JC131T (97.4 %) and Cohaesibacter gelatinilyticus CL-GR15T (97.3 %). Results of phylogenetic analysis showed that it was affiliated to the genus Cohaesibacter within the order Rhizobiales in the Alphaproteobacteria. The respiratory quinone of strain YE-B6T was Q-10. The cellular fatty acids mainly comprised C18 : 1 ω7c and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmonomethylethanolamine, two unidentified aminolipids, two unidentified polar lipids and one unidentified phospholipid. The G+C content of strain YE-B6T was 55.6 mol%. Based on its genotypic, physiological and biochemical characteristics, strain YE-B6T represented a novel species within the genus Cohaesibacter, for which the name Cohaesibacterintestini sp. nov. is proposed. The type strain of the new species is YE-B6T (=MCCC 1A13131T=KCTC 62716T).

Nonlabens xiamenensis sp. nov., isolated from coastal seawater.

A Gram-stain negative, rod-shaped and non-flagellated bacterium, designated strain 1Q3T, was isolated from coastal seawater in Xiamen Island, China, and subjected to taxonomic characterisation using a polyphasic approach. Strain 1Q3T was found to be aerobic, non-gliding and to lack flexirubin-type pigments. Catalase activity was found to be negative and oxidase positive. The strain has the ability to degrade protein. The nearly complete 16S rRNA gene sequence of strain 1Q3T shows high sequence similarities with Nonlabens aestuariivivens OITF-31T (96.1%), Nonlabens halophilus CAU 1131T and Nonlabens spongiae UST030701-156T (95.7% and 95.5%, respectively). Phylogenetic analysis based on 16S rRNA gene sequences and phylogenomic analysis based on a 92 bacterial core gene set indicated that strain 1Q3T should be affiliated to the genus Nonlabens, but forms a distinct monophyletic branch, which is separated from the other members within the genus Nonlabens. The predominant fatty acids (> 10%) were identified as iso-C17:0 3-OH, iso-C15:0 and anteiso-C15:0. The predominant respiratory quinone was found to be MK-6. The polar lipids were identified as phosphatidylethanolamine, a phospholipid, an aminolipid and three unidentified polar lipids. The draft genome size of strain 1Q3T is 3.7 Mb with genomic G + C content of 41.1 mol%. Based on these results, strain 1Q3T is concluded to represent a novel species within the genus Nonlabens, for which the name Nonlabens xiamenensis sp. nov. is proposed with the type strain 1Q3T (= MCCC 1A14023T = KCTC 62889T).

Lottiidibacillus patelloidae gen. nov., sp. nov., isolated from the intestinal tract of a marine limpet and reclassification of Bacillus taeanensis as Maribacillus taeanensis gen. nov., comb. nov.

A taxonomic study was carried out on strain SA5d-4T, which was isolated from a marine limpet (Patelloida saccharina lanx [Reeve, 1855]) collected from intertidal rocks in Xiamen, China. Strain SA5d-4T was aerobic, Gram-positive, lacked flagellum, non-motile, filamentous, formed a slightly-yellowish colony, and non-sporulating. The strain grew optimally at 28 °C, at pH values 7.0-8.0, and in the presence of 1-2% (w/v) sodium chloride. The major cellular fatty acids identified were iso-C15:0, iso-C17:0ω10c, and iso-C17:0. The dominated respiratory quinone was menaquinone-7. The major phospholipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylglycerol. The genomic DNA G + C content was 35.3 mol%, calculated from a draft genome sequence. Phylogenetic analysis based on the full-length 16S rRNA gene sequence showed that strain SA5d-4T belongs to a new genus within the family Bacillaceae, and this gene shares 95.6% similarity with that from Bacillus taeanensis BH030017T, 95.2% with Bacillus algicola KMM 3737T, 95.1% with Bacillus alkalinitrilicus ANL-iso4T, 94.9% with Bacillus hwajinpoensis SW-72T, and 94.6% with Anaerobacillus alkalidiazotrophicus MS6T. Whole genome phylogenetic analyses indicated that strain SA5d-4T formed a monophyletic branch with B. taeanensis BH030017T. The average nucleotide identity between strain SA5d-4T and B. taeanensis BH030017T was 69.6%. Based on polyphasic taxonomic characteristics, strain SA5d-4T represents a novel species of a new genus, for which the name Lottiidibacillus patelloidae gen. nov., sp. nov., is proposed with the type strain SA5d-4T (= MCCC 1A11654T = KCTC 33831T). Based on phylogenetic analyses, B. taeanensis should be transferred to a new genus, named Maribacillus, as Maribacillus taeanensis comb. nov., with type strain BH030017T (= KCTC 3918T = DSM 16466T).

Agaribacterium haliotis gen. nov., sp. nov., isolated from abalone faeces.

A marine bacterium, named strain feces2T, was isolated from the excreted faeces of an abalone, Haliotis discus hannai. The bacterium was Gram-stain-negative, rod-shaped and had a polar flagellum. It formed a white, small and crater-like colony on an agar plate, and had the capability of degrading agar. Activity of oxidase was positive and that of catalase was negative. Strain feces2T grew at 16 to 40 °C with an optimum of 28-30 °C. The nearly full-length 16S rRNA gene of strain feces2T had the greatest sequence similarity of 92.9 % with Marinibactrumhalimedae Q-192T, followed by of 92.8 % with Teredinibacterturnerae T7902T. Phylogenetic analysis indicated that strain feces2T belonged to the family Cellvibrionaceae, representing an independent clade with an uncultured bacterium clone NEP3-15 (98 % sequence similarity of 16S rRNA gene) derived from the phycosphere of Enteromorphaprolifera. The respiratory quinone was ubiquinone Q-8. The predominant fatty acids consisted of summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c), C16 : 0 and summed feature 3 (C16 : 1 ω6c/C16 : 1ω7c). The polar lipids were identified as phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified amino phospholipid and four unknown lipids. The genomic DNA G+C content was 50.5 mol%. On the basis of polyphasic characterizations, strain feces2T represented a novel species and a novel genus in the family Cellvibrionaceae of the order Cellvibrionales within the Gammaproteobacteria, for which the name Agaribacteriumhaliotis gen. nov., sp. nov. is proposed, with the type strain being feces2T (=MCCC 1A11750T=KCTC 52708T). [corrected].

Shewanella intestini sp. nov., isolated from the intestine of abalone, Haliotis diversicolor.

A Gram-stain-negative, rod-shaped bacterium with a singular polar flagellum, designated as strain XMDDZSB0408T, was isolated from the intestine of adult abalone, Haliotis diversicolor. Activity of oxidase was positive and catalase activity was negative. It could grow at salinities from 3 to 6 % NaCl (w/v), and pH 7-9. It had the highest sequence similarity of <96.0 % with all previously established species for the complete 16S rRNA gene (1531 bp). The results of phylogenetic analysis indicated that the strain was affiliated to the genus Shewanella and closely related to Shewanella gaetbuli TF-27T and Shewanella japonica KMM 3299T (95.8 % sequence similarity), Shewanella electrodiphila MAR441T (95.6 %), Shewanella pacifica KMM 3597T (95.4 %), Shewanella donghaensis LT17T (95.3 %) and Shewanella olleyana ACEM 9T (94.7 %). The respiratory quinones were MK-7, Q-8, Q-7, MK-8, Q-7 (H4) and Q-6. The predominant fatty acids consisted of C16:0, summed feature 3 (comprised of C16 : 1ω7c/C16 : 1ω6c), C18 : 0, summed feature 8 (comprised of C18 : 1ω7c/C18 : 1ω6c), C12 : 0 and C14 : 0. The polar lipids were identified as phosphatidylethanolamine (PE), a glycolipid (GL), a phospholipid (PL) and one unidentified lipid (L). The DNA G+C content was 41.4 mol% calculated from the draft genome sequence. On the basis of its polyphasic taxonomic properties, strain XMDDZSB0408T represented a novel species, for which the name Shewanella intestini sp. nov. was proposed, with the type strain XMDDZSB0408T (=KCTC 52125T=MCCC 1A01895T).