Oceanicella actignis gen. nov., sp. nov., a halophilic slightly thermophilic member of the Alphaproteobacteria

Mangrovicoccus algicola sp. nov., an alginate lyase - producing marine bacterium

A Gram-stain-negative, non-motile, ellipsoid bacterium, designated HB182678T, was isolated from brown alga collected from Hainan province, PR China. Growth was observed at 10-50 °C (optimum 37-40 °C), at pH 6-10 (optimum pH 8) and in the presence of 0.5-13% (w/v) NaCl (optimum, 2-4%). The predominant isoprenoid quinone was Q-10 and the major fatty acids were C18 : 1 ω7c, C16 : 0, C18 : 0 and C19 : 0 cyclo ω8c. The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, an unidentified phospholipid, two unidentified glycolipids and three unidentified aminophospholipids. The size of the draft genome was 4.40 Mbp with G+C content 68.8 mol%. Phylogenetic analysis of 16S rRNA gene sequence indicated that strain HB182678T belonged to the genus Mangrovicoccus, and the closest phylogenetically related species was Mangrovicoccus ximenensis T1lg56T (with the similarity of 96.3%). Whole genome average nucleotide identity (ANI) value between them was 84.3% and in silico DNA-DNA hybridization value was 27.2%. The combined phylogenetic relatedness, phenotypic and genotypic features supported the conclusion that strain HB182678T represents a novel species of the genus Mangrovicoccus, for which the name Mangrovicoccus algicola sp. nov. is proposed. The type strain is HB182678T (=MCCC 1K04624T=KCTC 82318T).

Halovulum marinum sp. nov., isolated from deep-sea water of the Indian Ocean, and emended description of the genus Halovulum

A novel Gram-stain-negative, aerobic, motile by peritrichous flagella, oval to rod-shaped bacterium, designated strain 2CG4^T, was isolated from a deep-sea water sample collected from the Northwest Indian Ocean. The results of phylogenetic analysis of both 16S rRNA gene and RpoC protein sequences indicated that this strain was affiliated with the genus Halovulum in the Amaricoccus clade of the family Rhodobacteraceae of the class Alphaproteobacteria, sharing 95.3 % similarity at the 16S rRNA gene sequence level with the type strain of Halovulum dunhuangense YYQ-30^T, the only species in the genus Halovulum. The predominant fatty acids (>10 %) of 2CG4^T were summed feature 8 (C_18 : 1ω7c and/ or C_18 : 1ω6c; 61.1 %) and cyclo-C_19 : 0ω8c (15.6 %). The polar lipids of 2CG4^T were phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine and sulfoquinovosyldiacylglycerol. The only isoprenoid quinone of 2CG4^T was ubiquinone-10. The DNA G+C content of 2CG4^T was determined to be 69.4 %. The central gene pufLM for the photosynthetic reaction was not detected. No growth occurred for 2CG4^T in the absence of NaCl. On the basis of these data, it is concluded that the 2CG4^T represents a novel species of the genus Halovulum, for which the name Halovulum marinum sp. nov. is proposed. The type strain is 2CG4^T (=CGMCC 1.16468^T=JCM 32611^T).

Analysis of 1,000+ Type-Strain Genomes Substantially Improves Taxonomic Classification of Alphaproteobacteria

The class Alphaproteobacteria is comprised of a diverse assemblage of Gram-negative bacteria that includes organisms of varying morphologies, physiologies and habitat preferences many of which are of clinical and ecological importance. Alphaproteobacteria classification has proved to be difficult, not least when taxonomic decisions rested heavily on a limited number of phenotypic features and interpretation of poorly resolved 16S rRNA gene trees. Despite progress in recent years regarding the classification of bacteria assigned to the class, there remains a need to further clarify taxonomic relationships. Here, draft genome sequences of a collection of genomes of more than 1000 Alphaproteobacteria and outgroup type strains were used to infer phylogenetic trees from genome-scale data using the principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families and genera, including taxa recognized as problematic long ago but also quite recent taxa, as well as a few species were shown to be in need of revision. According proposals are made for the recognition of new orders, families and genera, as well as the transfer of a variety of species to other genera and of a variety of genera to other families. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which are confirmed as valuable taxonomic markers. Similarly, analysis of the gene content was shown to provide valuable taxonomic insights in the class. Significant incongruities between 16S rRNA gene and whole genome trees were not found in the class. The incongruities that became obvious when comparing the results of the present study with existing classifications appeared to be caused mainly by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. Another probable cause of misclassifications in the past is the partially low overall fit of phenotypic characters to the sequence-based tree. Even though a significant degree of phylogenetic conservation was detected in all characters investigated, the overall fit to the tree varied considerably.

Physiological and genomic features of Paraoceanicella profunda gen. nov., sp. nov., a novel piezophile isolated from deep seawater of the Mariana Trench

A novel piezophilic alphaproteobacterium, strain D4M1^T, was isolated from deep seawater of the Mariana Trench. 16S rRNA gene analysis showed that strain D4M1^T was most closely related to Oceanicella actignis PRQ‐67^T (94.2%), Oceanibium sediminis O448^T (94.2%), and Thioclava electrotropha ElOx9^T (94.1%). Phylogenetic analyses based on both 16S rRNA gene and genome sequences showed that strain D4M1^T formed an independent monophyletic branch paralleled with the genus Oceanicella in the family Rhodobacteraceae. Cells were Gram‐stain‐negative, aerobic short rods, and grew optimally at 37°C, pH 6.5, and 3.0% (w/v) NaCl. Strain D4M1^T was piezophilic with the optimum pressure of 10 MPa. The principal fatty acids were C_18:1ω7c/C_18:1ω6c and C_16:0, major respiratory quinone was ubiquinone‐10, and predominant polar lipids were phosphatidylglycerol, phosphatidylethanolamine, and an unidentified aminophospholipid. The complete genome contained 5,468,583‐bp with a G + C content of 70.2 mol% and contained 4,855 protein‐coding genes and 78 RNA genes. Genomic analysis revealed abundant clues on bacterial high‐pressure adaptation and piezophilic lifestyle. The combined evidence shows that strain D4M1^T represents a novel species of a novel genus in the family Rhodobacteraceae, for which the name Paraoceanicella profunda gen. nov., sp. nov. is proposed (type strain D4M1^T = MCCC 1K03820^T = KCTC 72285^T).

Minwuia thermotolerans gen. nov., sp. nov., a marine bacterium forming a deep branch in the Alphaproteobacteria, and proposal of Minwuiaceae fam. nov. and Minwuiales ord. nov

Two Gram-stain-negative, strictly aerobic, non-motile, non-spore-forming, rod-shaped bacteria, designated as SY3-15^Tand SY3-13, were isolated from a seawater sample of the South China Sea. Colonies were 0.5-1.0 mm in diameter, smooth, circular, convex and translucent after growth on marine agar at 37 °C for 3 days. The strains were found to grow at 20-50 °C (optimum, 42 °C), pH 6.0-8.5 (optimum, pH 6.5-7.5) and with 0.5-6.0 % (w/v) NaCl (optimum, 1.5-2.0 %). Chemotaxonomic analysis showed the sole respiratory quinone to be ubiquinone-10, the major fatty acids (>10 %) were C16 : 0 3-OH, C19 : 0cyclo ω9c, C18 : 1 3-OH and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), and the polar lipids were phosphatidylglycerol, two unidentified aminolipids and three unidentified lipids. The DNA G+C content was 67.2-67.4 mol% calculated by genome. The 16S rRNA gene sequences of strains SY3-15^T and SY3-13 were identical and related to the genus Lutibaculum with a similarity of 92.1 %. The 16S rRNA gene phylogenetic trees reconstructed with neighbour-joining, maximum-parsimony and minimum-evolution methods showed that the strains constituted a deep and separated branch from other families of Alphaproteobacteria, and the phylogenetic trees based on concatenated 163 protein sequences from genome sequences showed that the clade in which strains SY3-15^T and SY3-13 located was separated from the clade of the other orders of Alphaproteobacteria, indicating it may represent a novel family of a novel order. Based on their phenotypic properties and their phylogenetic distinctiveness, we propose strains SY3-15^T (=MCCC 1K03467^T=KCTC 62335^T) and SY3-13 (=MCCC 1K03466=KCTC 62329) to represent a novel species of a novel genus with the name Minwuia thermotolerans gen. nov., sp. nov., and we propose Minwuiaceae fam. nov. and Minwuiales ord. nov. with Minwuia as the type genus.

Limibaculum halophilum gen. nov., sp. nov., a new member of the family Rhodobacteraceae

A Gram-stain-negative, cream-pigmented, aerobic, non-motile, non-spore-forming and short-rod-shaped bacterial strain, designated CAU 1123^T, was isolated from mud from reclaimed land. The strain's taxonomic position was investigated by using a polyphasic approach. Strain CAU 1123^T grew optimally at 37 °C and at pH 7.5 in the presence of 2 % (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain CAU 1123^T formed a monophyletic lineage within the family Rhodobacteraceae with 93.8 % or lower sequence similarity to representatives of the genera Rubrimonas, Oceanicella, Pleomorphobacterium, Rhodovulum and Albimonas. The major fatty acids were C18 : 1 ω7c and 11-methyl C18 : 1 ω7c and the predominant respiratory quinone was Q-10. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, two unidentified phospholipids, one unidentified aminolipid and one unidentified lipid. The DNA G+C content was 71.1 mol%. Based on the data from phenotypic, chemotaxonomic and phylogenetic studies, it is proposed that strain CAU 1123^T represents a novel genus and novel species of the family Rhodobacteraceae, for which the name Limibaculumhalophilum gen. nov., sp. nov. The type strain is CAU 1123^T (=KCTC 52187^T, =NBRC 112522^T).

Pleomorphobacterium xiamenense Yin et al. 2013 is a later heterotypic synonym of Oceanicella actignis Albuquerque et al. 2012

Pleomorphobacterium xiamenense CLWT was compared with Oceanicella actignis PRQ-67T to examine the taxonomic relationship between the two organisms. The 16S rRNA gene sequence comparison showed that the two strains had 99.9 % sequence similarity. Phylogenetic analysis showed the two strains formed an independent tight cluster, distinctly branching from the closely related species in the family Rhodobacteraceae. Whole genomic comparison between the two strains revealed a digital DNA-DNA hybridization estimate of 88.4 % and average nucleotide identity of 98.8 %, strongly supporting that the two strains represented a single species. In addition, neither strain displayed any striking difference in biochemical characteristics, fatty acid composition, and polar lipid profile. According to priority, Pleomorphobacterium xiamenense is reclassified as a later heterotypic synonym of Oceanicella actignis based on the phylogenetic relationship, whole genomic comparison, fatty acid composition and polar lipid profile, and other phenotypic and biochemical properties.

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, and these authors’ names will be included in the author index of the present issue. Inclusion of a name on these lists validates the publication of the name and thereby makes it available in bacteriological nomenclature. 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.