Kazachstania turicensis CAU Y1706 ameliorates atopic dermatitis by regulation of the gut-skin axis.

Atopic dermatitis (AD) causes chronic inflammatory skin disease that results in a considerable economic expense and social burden. Certain Lactobacillus strains ameliorate AD, but the effects of probiotic yeast on AD have not been investigated to date. In this study, we isolated Kazachstania turicensis CAU Y1706, commonly known as a kefir yeast, and evaluated its mitigating effects using an ovalbumin-sensitized AD mouse model. Overall, K. turicensis CAU Y1706 was generally effective against AD. Oral administration of K. turicensis CAU Y1706 suppressed T helper type 2 immune response factors by regulatory T cells and upregulation of T helper type 1 cytokine levels. Kazachstania turicensis CAU Y1706 also reduced IgE levels as well as the number of eosinophil and mast cells. Furthermore, feces from K. turicensis CAU Y1706-treated mice had more butyrate-producing bacteria, such as Lactobacillus, Bacteroides, Ruminococcus, and Akkermansia, although the level of Fecalibacterium was significantly reduced. Therefore, K. turicensis CAU Y1706 modulates immune responses as well as gut microbiota, thus indicating that it has potential for application as a supplement for alleviation of AD.

Arenibacillus arenosus gen. nov., sp. nov., a member of the family Rhodobacteraceae isolated from sea sand.

A Gram-stain-negative, aerobic, non-motile, non-spore-forming, rod-shaped bacterial strain, designated CAU 1304T, was isolated from sea sand. Strain CAU 1304T grew optimally at pH 8.5 and 30 °C and in the presence of 1 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CAU 1304T belonged to the family Rhodobacteraceae, and was most closely related to Roseicitreum antarcticum ZS2-28T (96.54 % similarity) and Rhodobacter veldkampii ATCC 35703T (96.46 %). The major fatty acid was C18 : 1ω7c and the respiratory quinone was Q-10. The polar lipids were composed of phosphatidylglycerol, phosphatidylcholine and an unidentified aminolipid. The DNA G+C content was 55.9 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic analysis, it is proposed that strain CAU 1304T represents a novel species of a new genus of the family Rhodobacteraceae, for which the name Arenibacillus arenosus gen. nov., sp. nov. is proposed. The type strain of Arenibacillus arenosus is CAU 1304T (=KCTC 42827T=NBRC 113022T).

Sphingomicrobium arenosum sp. nov., isolated from marine sediment.

A Gram-stain-negative, strictly aerobic, motile by one single flagellum, dark-orange pigmented and rod-shaped bacterial strain, designated CAU 1457T, was isolated from marine sediment in the Republic of Korea and its taxonomic position was investigated by using a polyphasic approach. The isolate grew optimally at 30 °C, at pH 6.0 and in the presence of 2 % (w/v) NaCl. Based on 16S rRNA gene sequences similarity, strain CAU 1457T belonged to the genus Sphingomicrobium and was related most closely to Sphingomicrobium astaxanthinifaciens JCM 18551T (98.2 % similarity). Strain CAU 1457T contained ubiquinone-10 as the predominant isoprenoid quinone and 11-methyl C18 : 1ω7c and summed feature 8 (C18 : 1ω7c/ω6c) as the major cellular fatty acids. Triamine sym-homospermidine was detected as the major compound in the polyamine pattern. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, four unidentified glycolipids, one unidentified aminophospholipid, two unidentified phospholipids, one unidentified aminolipid and one unidentified lipid. DNA-DNA relatedness between strain CAU 1457T and the closely related strains, Sphingomicrobium astaxanthinifaciens JCM 18551T and Sphingomicrobium aestuariivivum KCTC 42286T were 32.7 and 28.4 %, respectively. The DNA G+C content of strain was 68.8 mol%. The phenotypic, chemotaxonomic and phylogenetic data indicated that strain CAU 1457T represents a novel species of the genus Sphingomicrobium, for which the name Sphingomicrobium arenosum sp. nov. is proposed. The type strain is CAU 1457T (=KCTC 62233T=NBRC 113094T).

Arenimonas halophila sp. nov., isolated from soil.

A Gram-staining-negative, aerobic, non-motile, rod-shaped bacterium, designated CAU 1453T, was isolated from soil and its taxonomic position was investigated using a polyphasic approach. Strain CAU 1453T grew optimally at 30 °C and at pH 6.5 in the presence of 1 % (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that CAU 1453T represented a member of the genus Arenimonas and was most closely related to Arenimonas donghaensis KACC 11381T (97.2 % similarity). CAU 1453T contained ubiquinone-8 (Q-8) as the predominant isoprenoid quinone and iso-C15 : 0 and iso-C16 : 0 as the major cellular fatty acids. The polar lipids consisted of diphosphatidylglycerol, a phosphoglycolipid, an aminophospholipid, two unidentified phospholipids and two unidentified glycolipids. CAU 1453T showed low DNA-DNA relatedness with the most closely related strain, A. donghaensis KACC 11381T (26.5 %). The DNA G+C content was 67.3 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, CAU 1453T represents a novel species of the genus Arenimonas, for which the name Arenimonas halophila sp. nov. is proposed. The type strain is CAU 1453T (=KCTC 62235T=NBRC 113093T).

Arthrobacter paludis sp. nov., isolated from a marsh.

A novel Gram-stain-positive, strictly aerobic, non-endospore-forming bacterium, designated CAU 9143T, was isolated from a hydric soil sample collected from Seogmo Island in the Republic of Korea. Strain CAU 9143T grew optimally at 30 °C, at pH 7.0 and in the presence of 1 % (w/v) NaCl. The phylogenetic trees based on 16S rRNA gene sequences revealed that strain CAU 9143T belonged to the genus Arthrobacter and was closely related to Arthrobacter ginkgonis SYP-A7299T (97.1 % similarity). Strain CAU 9143T contained menaquinone MK-9 (H2) as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two glycolipids and two unidentified phospholipids as the major polar lipids. The whole-cell sugars were glucose and galactose. The peptidoglycan type was A4a (l-Lys-D-Glu2) and the major cellular fatty acid was anteiso-C15 : 0. The DNA G+C content was 64.4 mol% and the level of DNA-DNA relatedness between CAU 9143T and the most closely related strain, A. ginkgonis SYP-A7299T, was 22.3 %. Based on phenotypic, chemotaxonomic and genetic data, strain CAU 9143T represents a novel species of the genus Arthrobacter, for which the name Arthrobacterpaludis sp. nov. is proposed. The type strain is CAU 9143T (=KCTC 13958T,=CECT 8917T).