Hanstruepera crassostreae He et al. 2018 is a later heterotypic synonym of Pseudobizionia ponticola Park et al. 2018 and transfer of Pseudobizionia ponticola to the genus Hanstruepera as Hanstruepera ponticola comb. nov

The 16S rRNA gene sequences of Pseudobizionia ponticola MM-14^T and Hanstruepera crassostreae L53^T shared 100 % sequence similarity. This study aimed to clarify the taxonomic position of the two species. Whole-genome comparisons showed that P. ponticola MM-14^T and H. crassostreae L53^T shared average nucleotide identity of 97.52 %, digital DNA-DNA hybridization of 75.30 % and average amino acid identity of 96.98 %. These values exceeded the threshold of bacterial species delineation. Furthermore, average amino acid identities of P. ponticola MM-14^T and H. crassostreae L53^T in comparison with Hanstruepera neustonica CC-PY-50^T were 82.04 and 82.11 %, respectively. Phylogenetic analysis based on 16S rRNA gene and 120 bacterial conserved single-copy genes also supported that P. ponticola MM-14^T and H. crassostreae L53^T belonged to the genus Hanstruepera. Phenotypic and chemical taxonomic properties compared between P. ponticola MM-14^T and H. crassostreae L53^T were nearly identical. Colonies of the two species on marine agar plates were orange-pigmented, circular and smooth. Flexirubin-type pigments were present in both H. crassostreae L53^T and P. ponticola MM-14^T. The major fatty acids composition of the two species consisted of iso-C_15 : 1 G, iso-C_15 : 0, and iso-C_17 : 0 3-OH, similar to H. neustonica CC-PY-50^T. Based on priority, H. crassostreae He et al. 2018 is a later heterotypic synonym of P. ponticola Park et al. 2018, and P. ponticola should be transferred to the genus Hanstruepera as Hanstruepera ponticola comb. nov.

Analysis of 1,000 Type-Strain Genomes Improves Taxonomic Classification of Bacteroidetes

Although considerable progress has been made in recent years regarding the classification of bacteria assigned to the phylum Bacteroidetes, there remains a need to further clarify taxonomic relationships within a diverse assemblage that includes organisms of clinical, piscicultural, and ecological importance. Bacteroidetes classification has proved to be difficult, not least when taxonomic decisions rested heavily on interpretation of poorly resolved 16S rRNA gene trees and a limited number of phenotypic features. Here, draft genome sequences of a greatly enlarged collection of genomes of more than 1,000 Bacteroidetes 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 proposed long ago such as Bacteroides, Cytophaga, and Flavobacterium 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. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which can be considered valuable taxonomic markers. We detected many incongruities when comparing the results of the present study with existing classifications, which appear to be caused by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. The few significant incongruities found between 16S rRNA gene and whole genome trees underline the pitfalls inherent in phylogenies based upon single gene sequences and the impediment in using ordinary bootstrapping in phylogenomic studies, particularly when combined with too narrow gene selections. While a significant degree of phylogenetic conservation was detected in all phenotypic characters investigated, the overall fit to the tree varied considerably, which is one of the probable causes of misclassifications in the past, much like the use of plesiomorphic character states as diagnostic features.

Hanstruepera crassostreae sp. nov., a novel marine bacterium of the family Flavobacteriaceae isolated from an oyster

A Gram-stain-negative, rod-shaped, non-motile, aerobic and orange-pigmented marine bacterium, designated strain L53^T, was isolated from an oyster sample collected from the coast of Weihai, China (122.0° E 37.5° N). Growth of strain L53^T occurred at 4-40 °C (optimum, 33 °C), at pH 6.5-8.0 (optimum, pH 7.5) and with 1.0-7.0 % (w/v) NaCl (optimum, 3.0 %). Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain L53^T was closely related to Bizionia echini KCTC 22015^T (96.9 %) and Hanstruepera neustonica JCM 19743^T (96.1 %). Strain L53^T was located in a distinct phyletic lineage in a discrete clade associated with H. neustonica JCM 19743^T. The DNA G+C content of strain L53^T was 33.5 mol%. The sole menaquinone was MK-6. The polar lipids comprised one phosphatidylethanolamine, four unidentified aminolipids and four unidentified lipids. The major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 0 G. Based on morphological, physiological and molecular properties as well as on phylogenetic distinctiveness, strain L53^T should be placed in the genus Hanstruepera as representing a novel species, for which the name Hanstruepera crassostreae sp. nov. is proposed. The type strain is L53^T (=KCTC 62247^T=MCCC 1H00246^T).

Pseudobizionia ponticola gen. nov., sp. nov., isolated from seawater

A Gram-stain-negative, aerobic, non-motile and ovoid or rod-shaped bacterial strain, designated MM-14^T, was isolated from seawater sampled from the Yellow Sea in the Republic of Korea and its taxonomic position was investigated using a polyphasic approach. Strain MM-14^T grew optimally at 30 °C and in the presence of approximately 2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain MM-14^T clustered with the type strain of Hanstruepera neustonica. The novel strain exhibited a 16S rRNA gene sequence similarity value of 96.06 % to the type strain of H. neustonica, but higher 16S rRNA gene sequence similarity values (96.13-96.69 %) to the type strains of Bizionia echini, Bizionia hallyeonensis and Bizionia psychrotolerans. Strain MM-14^T contained MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH as the major fatty acids. The major polar lipids were phosphatidylethanolamine, one unidentified lipid and one unidentified aminolipid. The DNA G+C content of strain MM-14^T was 34.6 mol%. The phylogenetic and chemotaxonomic data and other phenotypic properties revealed that strain MM-14^T constitutes a new genus and species within the family Flavobacteriaceae of the phylum Bacteroidetes, for which the name Pseudobizionia ponticola gen. nov., sp. nov. is proposed. The type strain of Pseudobizionia ponticola is MM-14^T (=KACC 19434^T=KCTC 62139^T=NBRC 113019^T).

Hans Georg Trüper (1936-2016) and His Contributions to Halophile Research

Prof. Hans Georg Trüper, one of the most important scientists in the field of halophile research, passed away on 9 March 2016 at the age of 79. I here present a brief obituary with special emphasis on Prof. Trüper's contributions to our understanding of the halophilic prokaryotes and their adaptations to life in hypersaline environments. He has pioneered the study of the halophilic anoxygenic phototrophic sulfur bacteria of the Ectothiorhodospira-Halorhodospira group. Some of the species he and his group isolated from hypersaline and haloalkaline environments have become model organisms for the study of the mechanisms of haloadaptation: the functions of three major organic compounds - glycine betaine, ectoine, and trehalose - known to serve as "compatible solutes" in halophilic members of the Bacteria domain, were discovered during studies of these anoxygenic phototrophs. Prof. Trüper's studies of hypersaline alkaline environments in Egypt also led to the isolation of the first known extremely halophilic archaeon (Natronomonas pharaonis). The guest editors dedicate this special volume of Life to the memory of Prof. Hans Georg Trüper.

Xanthomarina gelatinilytica gen. nov., sp. nov., isolated from seawater

A novel Gram-stain-negative, rod-shaped, yellow-pigmented, non-sporulating, non-motile bacterium, designated strain AK20T, was isolated from seawater collected from Kochi city, Kerala state, India. Colonies on marine agar were circular, yellow, shiny, translucent, 2-3 mm in diameter, convex and with entire margin. Flexirubin-type pigment was present. The fatty acids were dominated by iso-branched units with a high abundance of iso-C15:0, iso-C15:1 G, iso-C17:0 3-OH, summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH) and iso-C15:0 3-OH. Polar lipids included phosphatidylethanolamine, two unidentified aminophospholipids, two unidentified phospholipids and four unidentified lipids. Menaquinone 6 (MK-6) was the predominant respiratory quinone. The DNA G+C content of strain AK20T was 38.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain AK20T was closely related to Formosa spongicola A2T and Bizionia paragorgiae KMM 6029T (pair-wise sequence similarities of 95.9 and 95.7%, respectively), forming a distinct branch within the family Flavobacteriaceae and clustering with the clade comprising species of the genus Bizionia. Based on phenotypic and chemotaxonomic characteristics and phylogenetic analysis, strain AK20T is different from the existing genera in the family Flavobacteriaceae, and is therefore considered to represent a novel species of a new genus, for which the name Xanthomarina gelatinilytica gen. nov., sp. nov. is proposed. The type strain of Xanthomarina gelatinilytica is AK20T ( = MTCC 11705T = JCM 18821T).