Halocynthiibacter namhaensis gen. nov., sp. nov., a novel alphaproteobacterium isolated from sea squirt Halocynthia roretzi

Halocynthiibacter halioticoli sp. nov., isolated from the viscera of abalone Haliotis discus hannai

A Gram-stain-negative, rod-shaped, glide, non-flagellated, and facultatively anaerobic bacterial strain, designated as Z654T, was isolated from the gut of abalone Haliotis discus hannai from Rongcheng, Shandong province, China. Cells are 0.2-0.8 μm in width and 0.7-3.4 μm in length. Cells grew best at 30 °C (range, 15-37 °C), pH 7.0 (range, 6.0-8.5) and NaCl concentration of 2.0% (w/v) (range, 1-10%). According to the phylogenetic analysis of 16S rRNA gene sequence, the strain belongs to the genus Halocynthiibacter and the closest strain is Halocynthiibacter arcticus KCTC 42129 T (97.12%). The genome size of strain Z654T was 3,296,250 bp and the DNA G + C content was 54.2 mol%. The average nucleotide identity (ANI) scores and digital DNA-DNA hybridization (dDDH) scores with H. arcticus KCTC 42129 T were 70% and 14.6-18.2%, respectively. The predominant quinone was Q-10 and the major fatty acids were C18:0, C18:1 ω7c 11-methyl and summed feature 8. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, unidentified aminolipid and unidentifed lipids. Based on the phenotypic, phylogenetic and chemotaxonomic data, strain Z654T was considered to represent a novel species of the genus Halocynthiibacter, for which the name Halocynthiibacte halioticoli sp. nov., is proposed. The type strain is Z654T (= MCCC 1H00503T = KCTC 92003 T).

Carapace microbiota in American lobsters (Homarus americanus) associated with epizootic shell disease and the green gland

Epizootic Shell Disease (ESD) has posed a great threat, both ecologically and economically, to the American lobster population of Long Island Sound since its emergence in the late 1990s. Because of the polymicrobial nature of carapace infections, causative agents for ESD remain unclear. In this study, we aimed to identify carapace microbiota associated with ESD and its potential impact on the microbiota of internal organs (green gland, hepatopancreas, intestine, and testis) using high-throughput 16S rRNA gene sequencing. We found that lobsters with ESD harbored specific carapace microbiota characterized by high abundance of Aquimarina, which was significantly different from healthy lobsters. PICRUSt analysis showed that metabolic pathways such as amino acid metabolism were enriched in the carapace microbiota of lobsters with ESD. Aquimarina, Halocynthiibacter, and Tenacibaculum were identified as core carapace bacteria associated with ESD. Particularly, Aquimarina and Halocynthiibacter were detected in the green gland, hepatopancreas, and testis of lobsters with ESD, but were absent from all internal organs tested in healthy lobsters. Hierarchical clustering analysis revealed that the carapace microbiota of lobsters with ESD was closely related to the green gland microbiota, whereas the carapace microbiota of healthy lobsters was more similar to the testis microbiota. Taken together, our findings suggest that ESD is associated with alterations in the structure and function of carapace microbiota, which may facilitate the invasion of bacteria into the green gland.

Cochlodiniinecator piscidefendens gen. nov., sp. nov., an algicidal bacterium against the ichthyotoxic dinoflagellate Cochlodinium polykrikoides

Harmful algal blooms caused by Cochlodinium polykrikoides result in enormous economic damage to the aquaculture industry. Biological control methods have attracted wide attention due to their environmental-friendliness. In this study, a novel algicidal bacterium, designated strain M26A2M^T, was determined for its taxonomic position and was evaluated for its potential to mitigate C. polykrikoides blooms. Strain M26A2M^T exhibited the highest 16S rRNA gene sequence similarity to the type strains of Planktotalea lamellibrachiae (97.3%), Halocynthiibacter namhaensis (97.2%), Pseudohalocynthiibacter aestuariivivens (96.8%) and Halocynthiibacter arcticus (96.4%) in the family Rhodobacteraceae. The predominant fatty acids were C_{10 : 0} 3-OH and summed feature 8 (comprising C_{18 : 1} ω7c and/or C_{18 : 1} ω6c). The major polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and three unidentified lipids. Q-10 was the respiratory quinone. Strain M26A2M^T exerted significant algicidal activity against C. polykrikoides cells by destroying the membrane integrity and the photosynthetic system. Our findings suggest that strain M26A2M^T shows a high potential to control outbreaks of C. polykrikoides. Based on the polyphasic characterization, strain M26A2M^T is considered to represent a novel species within a novel genus of the family Rhodobacteraceae, for which the name Cochlodiniinecator piscidefendens gen. nov., sp. nov. is proposed. The type strain is M26A2M^T (=KCTC 82083^T=JCM 34119^T).

Paenihalocynthiibacter styelae gen. nov., sp. nov., isolated from stalked sea squirt Styela clava

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strain, MYP1-1^T, was isolated from the intestine of a stalked sea squirt (Styela clava) of the South Sea in the Republic of Korea. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain MYP1-1^T clustered with the type strains of Halocynthiibacter species and Pseudohalocynthiibacter aestuariivivens. Strain MYP1-1^T exhibited 16S rRNA gene sequence similarity values of 97.0-97.6 % to the type strains of Halocynthiibacter namhaensis, Halocynthiibacter arcticus and P. aestuariivivens. The phylogenetic tree based on genomic sequences showed that strain MYP1-1^T formed a distinct branch separating it from the type strains of two Halocynthiibacter species and P. aestuariivivens and other taxa. The DNA G+C content of strain MYP1-1^T from its genomic sequence was 55.0 mol%. Strain MYP1-1^T contained Q-10 as the predominant ubiquinone and C_18 : 1  ω7c as the major fatty acid. The major polar lipids of strain MYP1-1^T were phosphatidylcholine, phosphatidylglycerol, one unidentified lipid and one unidentified aminolipid. The differences in fatty acid and polar lipid profiles and other differential phenotypic properties made it reasonable to distinguish strain MYP1-1^T from the genera Halocynthiibacter and Pseudohalocynthiibacter. On the basis of the polyphasic taxonomic investigations, we conclude that strain MYP1-1^T constitutes a new genus and species within the class Alphaproteobacteria, for which the name Paenihalocynthiibacter styelae gen. nov., sp. nov. is proposed. The type strain is MYP1-1^T (=KCTC 82143^T=NBRC 114355^T).

Roseobacters in a Sea of Poly- and Paraphyly: Whole Genome-Based Taxonomy of the Family Rhodobacteraceae and the Proposal for the Split of the "Roseobacter Clade" Into a Novel Family, Roseobacteraceae fam. nov

The family Rhodobacteraceae consists of alphaproteobacteria that are metabolically, phenotypically, and ecologically diverse. It includes the roseobacter clade, an informal designation, representing one of the most abundant groups of marine bacteria. The rapid pace of discovery of novel roseobacters in the last three decades meant that the best practice for taxonomic classification, a polyphasic approach utilizing phenotypic, genotypic, and phylogenetic characteristics, was not always followed. Early efforts for classification relied heavily on 16S rRNA gene sequence similarity and resulted in numerous taxonomic inconsistencies, with several poly- and paraphyletic genera within this family. Next-generation sequencing technologies have allowed whole-genome sequences to be obtained for most type strains, making a revision of their taxonomy possible. In this study, we performed whole-genome phylogenetic and genotypic analyses combined with a meta-analysis of phenotypic data to review taxonomic classifications of 331 type strains (under 119 genera) within the Rhodobacteraceae family. Representatives of the roseobacter clade not only have different environmental adaptions from other Rhodobacteraceae isolates but were also found to be distinct based on genomic, phylogenetic, and in silico-predicted phenotypic data. As such, we propose to move this group of bacteria into a new family, Roseobacteraceae fam. nov. In total, reclassifications resulted to 327 species and 128 genera, suggesting that misidentification is more problematic at the genus than species level. By resolving taxonomic inconsistencies of type strains within this family, we have established a set of coherent criteria based on whole-genome-based analyses that will help guide future taxonomic efforts and prevent the propagation of errors.

The Majority of Active Rhodobacteraceae in Marine Sediments Belong to Uncultured Genera: A Molecular Approach to Link Their Distribution to Environmental Conditions

General studies on benthic microbial communities focus on fundamental biogeochemical processes or the most abundant constituents. Thereby, minor fractions such as the Rhodobacteraceae are frequently neglected. Even though this family belongs to the most widely distributed bacteria in the marine environment, their proportion on benthic microbial communities is usually within or below the single digit range. Thus, knowledge on these community members is limited, even though their absolute numbers might exceed those from the pelagic zone by orders of magnitudes. To unravel the distribution and diversity of benthic, metabolically active Rhodobacteraceae, we have now analyzed an already existing library of bacterial 16S rRNA transcripts. The dataset originated from 154 individual sediment samples comprising seven oceanic regions and a broad variety of environmental conditions. Across all samples, a total of 0.7% of all 16S rRNA transcripts was annotated as Rhodobacteraceae. Among those, Sulfitobacter, Paracoccus, and Phaeomarinomonas were the most abundant cultured representatives, but the majority (78%) was affiliated to uncultured family members. To define them, the 45 most abundant Rhodobacteraceae-OTUs assigned as "uncultured" were phylogenetically assembled in new clusters. Their next relatives particularly belonged to different subgroups other than the Roseobacter group, reflecting a large part of the hidden diversity within the benthic Rhodobacteraceae with unknown functions. The general composition of active Rhodobacteraceae communities was found to be specific for the geographical location, exhibiting a decreasing richness with sediment depth. One-third of the Rhodobacteraceae-OTUs significantly responded to the prevailing redox regime, suggesting an adaption to anoxic conditions. A possible approach to predict their physiological properties is to identify the metabolic capabilities of their nearest relatives. Those need to be proven by physiological experiments, as soon an isolate is available. Because many uncultured members of these subgroups likely thrive under anoxic conditions, in future research, a molecular-guided cultivation strategy can be pursued to isolate novel Rhodobacteraceae from sediments.

Profundibacter amoris gen. nov., sp. nov., a new member of the Roseobacter clade isolated from Loki’s Castle Vent Field on the Arctic Mid-Ocean Ridge

A bacterial strain, designated BAR1T, was isolated from a microbial mat growing on the surface of a barite chimney at the Loki’s Castle Vent Field, at a depth of 2216 m. Cells of strain BAR1T were rod-shaped, Gram-reaction-negative and grew on marine broth 2216 at 10–37 °C (optimum 27–35 °C), pH 5.5–8.0 (optimum pH 6.5–7.5) and 0.5–5.0 % NaCl (optimum 2 %). The DNA G+C content was 57.38 mol%. The membrane-associated major ubiquinone was Q-10, the fatty acid profile was dominated by C18 : 1ω7c (91 %), and the polar lipids detected were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid, one unidentified lipid and one unidentified phospholipid. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain BAR1T clustered together with Rhodobacterales bacterium PRT1, as well as the genera Halocynthiibacter and Pseudohalocynthiibacter in a polyphyletic clade within the Roseobacter clade. Several characteristics differentiate strain BAR1T from the aforementioned genera, including its motility, its piezophilic behaviour and its ability to grow at 35 °C and under anaerobic conditions. Accordingly, strain BAR1T is considered to represent a novel genus and species within the Roseobacter clade, for which the name Profundibacter amoris gen. nov., sp. nov. is proposed. The type strain is Profundibacter amoris BAR1T (=JCM 31874T=DSM 104147T).

Amylibacter cionae sp. nov., isolated from the sea squirt Ciona savignyi

A Gram-stain-negative, non-motile, aerobic and rod-shaped bacterial strain, designated H-12T, was isolated from a sea squirt (Ciona savignyi) collected from Tsingtao Port, Jiaozhou Bay, China, and its taxonomic position was investigated. Strain H-12T grew optimally at 25-30 °C, at pH 7.0-8.0 and in the presence of 3.0-4.0 % (w/v) NaCl. The 16S rRNA gene sequence of strain H-12T exhibited the highest similarity to that of the type strain of Amylibacter marinus (95.3 %). A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain H-12T clustered with the type strain of A. marinus. The predominant ubiquinone in strain H-12T was identified as Q-10. The major fatty acids of strain H-12T were C18 : 1ω7c and C18 : 1ω7c 11-methyl. The major polar lipids detected in strain H-12T were phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, one unidentified aminolipid, two unidentified phospholipids and five unidentified lipids. The DNA G+C content of strain H-12T was 52.7 mol%. On the basis of phylogenetic, chemotaxonomic and phenotypic properties, strain H-12T is considered to represent a novel species within the genus Amylibacter, for which the name Amylibacter cionae sp. nov. is proposed. The type strain is H-12T (=KCTC 52581T=CGMCC 1.15880T).

Complete genome sequence of Halocynthiibacter arcticus PAMC 20958(T) from an Arctic marine sediment sample

Here, we present the first complete genome sequence of the strain PAMC 20958(T) from the genus Halocynthiibacter. Halocynthiibacter arcticus PAMC 20958(T), isolated from a marine sediment of the Arctic, is a gram-negative, aerobic, and rod-shaped bacterium. The complete genome contains 4,329,554 base pairs with 53.21% GC content and a 44,566 base pair plasmid with 48.72% GC content. This genome contained genes encoding alkaline phosphatase and lipase, and genes that confer resistance to arsenic, cadmium, tellurite, and acriflavin.

Halocynthiibacter arcticus sp. nov., isolated from Arctic marine sediment

A Gram-staining-negative, oxidase- and catalase-positive, non-motile, aerobic and rod-shaped bacterium producing white colonies, PAMC 20958^T, was isolated from a marine sediment of the Arctic. PAMC 20958^T grew at 10-27 °C (optimally at 21 °C), at pH 5.5-9.5 (optimally at pH 7.0-7.5) and in the presence of 0.5-7.5 % (w/v) (optimally at 2.0 %) NaCl. PAMC 20958^T showed 97.5 % 16S rRNA gene sequence similarity with Halocynthiibacter namhaensis KCTC 32362^T and formed a robust phylogenetic clade with this species. The average nucleotide identity value between strain PAMC 20958^T and H. namhaensis KCTC 32362^T was 79.7 % and the genome-to-genome distance was 13.0 % on average. The genomic DNA G+C content calculated from the genome sequence was 53.2 mol%. The major fatty acids were C_18 : 1ω7c and/or C_18 : 1ω6c. The major respiratory isoprenoid quinone was ubiquinone-10 (Q-10) and major polar lipids were phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and two unidentified lipids. On the basis of phylogenetic analysis and genotypic and phenotypic data obtained in this study, it is concluded that strain PAMC 20958^T ( = KCTC 42129^T = JCM 30530^T) represents the type strain of a novel species of the genus Halocynthiibacter, for which the name Halocynthiibacter arcticus sp. nov. is proposed.

Pseudohalocynthiibacter aestuariivivens gen. nov., sp. nov., isolated from a tidal flat

A Gram-stain-negative, non-motile, aerobic and coccoid, ovoid or rod-shaped bacterial strain, designated BS-W9T, was isolated from a tidal flat of the South Sea, South Korea. Strain BS-W9T grew optimally at 25–30 °C, at pH 7.0–8.0 and in the presence of approximately 2.0 % (w/v) NaCl. Phylogenetic trees, based on 16S rRNA gene sequences, revealed that strain BS-W9T clustered with the type strain of Halocynthiibacter namhaensis , showing a highest sequence similarity of 97.3 %. It exhibited sequence similarity values of less than 95.6 % to the type strains of other species with validly published names. Strain BS-W9T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the predominant fatty acid. The major polar lipids of strain BS-W9T were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, one unidentified lipid and one unidentified aminolipid. The fatty acid and polar lipid profiles of strain BS-W9T were distinguished from those of the type strains of H. namhaensis and other phylogenetically related genera. The DNA G+C content of strain BS-W9T was 53.2 mol% and its mean DNA–DNA relatedness value with H. namhaensis RA2-3T was 14 %. On the basis of the phylogenetic, chemotaxonomic and other phenotypic properties, strain BS-W9T is considered to represent a novel genus and species within the family Rhodobacteraceae , for which the name Pseudohalocyntiibacter aestuariivivens gen. nov., sp. nov. is proposed. The type strain of Pseudohalocyntiibacter aestuariivivens is BS-W9T ( = KCTC 42348T = CECT 8726T).

Ascidiaceihabitans donghaensis gen. nov., sp. nov., isolated from the golden sea squirt Halocynthia aurantium

A Gram-stain-negative, aerobic, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated RSS1-M3T, was isolated from a golden sea squirt (Halocynthia aurantium) collected from the East Sea, South Korea. Strain RSS1-M3T grew optimally at 30 °C, at pH 7.0–8.0 and in presence of 2.0 % (w/v) NaCl. Strain RSS1-M3T exhibited the highest 16S rRNA gene sequence similarity (96.55 %) to the type strain of Pelagicola litoralis . Neighbour-joining and maximum-likelihood phylogenetic trees based on 16S rRNA gene sequences revealed that strain RSS1-M3T clustered with the type strains, or proposed type strains, of Planktotalea frisia , Pacificibacter maritimus , Roseovarius marinus and Halocynthiibacter namhaensis , showing sequence similarity of 94.88–96.32 %. Strain RSS1-M3T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c and C16 : 0 as the major fatty acids. The polar lipid profile of strain RSS1-M3T, containing phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, one unidentified aminolipid and one unidentified lipid as major components, could be distinguished from those of the phylogenetically related genera. The DNA G+C content of strain RSS1-M3T was 55.8 mol%. On the basis of the phylogenetic, chemotaxonomic and phenotypic properties, strain RSS1-M3T is considered to represent a novel species of a new genus within the class Alphaproteobacteria , for which the name Ascidiaceihabitans donghaensis gen. nov., sp. nov. is proposed. The type strain is RSS1-M3T ( = KCTC 42118T = CECT 8599T).

List of new names and new combinations previously effectively, but not validly, published

The purpose of this announcement is to effect the valid publication of the following effectively published new names and new combinations under the procedure described in the Bacteriological Code (1990 Revision). Authors and other individuals wishing to have new names and/or combinations included in future lists should send three copies of the pertinent reprint or photocopies thereof, or an electronic copy of the published paper to the IJSEM Editorial Office for confirmation that all of the other requirements for valid publication have been met. It is also a requirement of IJSEM and the ICSP that authors of new species, new subspecies and new combinations provide evidence that types are deposited in two recognized culture collections in two different countries. It should be noted that the date of valid publication of these new names and combinations is the date of publication of this list, not the date of the original publication of the names and combinations. The authors of the new names and combinations are as given below. Inclusion of a name on these lists validates the publication of the name and thereby makes it available in the nomenclature of prokaryotes. The inclusion of a name on this list is not to be construed as taxonomic acceptance of the taxon to which the name is applied. Indeed, some of these names may, in time, be shown to be synonyms, or the organisms may be transferred to another genus, thus necessitating the creation of a new combination.