Flavicella sediminum sp. nov., isolated from marine sediment

A novel, Gram-stain-negative, motile, flagellated, aerobic, rod-shaped (0.5-0.7 µm wide and 1.0-1.2 µm long) and faint-yellow strain, designated ALS 84^T, was isolated from marine sediment sampled at Ailian bay, Rongcheng, PR China. Growth occurred in the presence of 1-3 % (w/v) NaCl (optimum, 2 % NaCl), at pH 4.0-8.0 (pH 6.0-7.0) and at 8-30 °C (28 °C). The genome size was 4.37 Mbp. The G+C content of the genomic DNA was 33.6 mol%. The results of phylogenetic analysis based on 16S rRNA gene sequences suggested that strain ALS 84^T belongs to the genus Flavicella within the family Flavobacteriaceae, and is most closely related to Flavicella marina (95.6 % similarity). The major fatty acids (>10 %) were iso-C_{15 : 0} 3-OH (22.9 %), iso-C_{15 : 0} (14.0 %) and C_{16 : 0} (10.9 %). The major polar lipids were phosphatidylethanolamine and three unidentified lipids. Menaquinone-6 (MK-6) was identified as the respiratory quinone. On the basis of the phenotypic, phylogenetic and chemotaxonomic data obtained in the study, strain ALS 84^T is considered to represent a novel species of the genus Flavicella, for which the name Flavicella sediminum sp. nov. is proposed. The type strain of the novel species is strain ALS 84^T (=KCTC 62398^T=MCCC 1K03480^T).

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.

Wenyingzhuangia fucanilytica sp. nov., a sulfated fucan utilizing bacterium isolated from shallow coastal seawater

A Gram-staining-negative, rod-shaped, strictly aerobic, non-flagellated, non-gliding and yellow-pigmented bacterial strain, designated as strain CZ1127T, capable of utilizing sulfated fucan, was isolated from shallow coastal seawater of Jiaozhou Bay, Qingdao, PR China. Its taxonomic position was investigated by a polyphasic approach. CZ1127T grew at 15-37 °C (optimum, 25 °C), pH 5.5-9.0 (optimum, pH 6.5-7.5) and in the presence of 0-4 % (w/v) NaCl [optimum, 0-3 % (w/v)]. CZ1127T contained MK-6 as the sole menaquinone, and iso-C15 : 0, iso-C17 : 0 3-OH, C16 : 1ω7c/C16 : 1ω6c and iso-C15 : 0 3-OH as its major fatty acids. The DNA G+C content of strain CZ1127T was 32.2 mol%. Phylogenetic analysis based on the 16S rRNA gene indicated that strain CZ1127T clustered with members of the genus Wenyingzhuangia and was closely related to Wenyingzhuangia marina CGMCC 1.12162T (97.4 % 16S rRNA gene sequence similarity) and Wenyingzhuangia gracilariae KCTC 42246T (96.1 %). The DNA-DNA relatedness between strain CZ1127T and W. marina CGMCC 1.12162T was 41.9±1.5 %. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, CZ1127T represents a novel species of the genus Wenyingzhuangia, for which the name Wenyingzhuangia fucanilytica sp. nov. is proposed. The type strain is CZ1127T (=CCTCC AB 2015089T=KCTC 42864T).

Wenyingzhuangia gracilariae sp. nov., a novel marine bacterium of the phylum Bacteroidetes isolated from the red alga Gracilaria vermiculophylla

A Gram-negative, strictly aerobic, beige-pigmented, non-motile, rod-shaped bacterial strain designated N5DB13-4(T) was isolated from the red alga Gracilaria vermiculophylla (Rhodophyta) collected at Sodegaura Beach, Chiba, Japan. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that the novel isolate is affiliated with the family Flavobacteriaceae within the phylum Bacteroidetes and that it showed highest sequence similarity (97.3 %) to Wenyingzhuangia heitensis H-MN17(T). The hybridization values for DNA-DNA relatedness between the strains N5DB13-4(T) and W. heitensis H-MN17(T) were 34.1 ± 3.5 %, which is below the threshold accepted for the phylogenetic definition of a novel prokaryotic species. The DNA G+C content of strain N5DB13-4(T) was determined to be 31.8 mol%; MK-6 was identified as the major menaquinone; and the presence of iso-C15:0, iso-C15:0 3-OH and iso-C17:0 3-OH as the major (>10 %) cellular fatty acids. A complex polar lipid profile was present consisting of phosphatidylethanolamine, two unidentified glycolipids and four unidentified lipids. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel species of the genus Wenyingzhuangia for which the name Wenyingzhuangia gracilariae sp. nov. is proposed. The type strain of W. gracilariae sp. nov. is N5DB13-4(T) (=KCTC 42246 (T)=NBRC 110602(T)).