Virgibacillus subterraneus sp. nov., a moderately halophilic Gram-positive bacterium isolated from subsurface saline soil

Seabuckthorn polysaccharide ameliorates high-fat diet-induced obesity by gut microbiota-SCFAs-liver axis

Obesity has been reported to be associated with gut microbiome dysbiosis. seabuckthorn fruits have traditionally been used in Tibetan foods and medicines for thousands of years. Seabuckthorn polysaccharide (SP) is one of the main functional components in seabuckthorn fruits. However, the effects of SP on a high-fat diet (HFD)-induced obesity have not yet been elucidated. The purpose of this study is to explore the amelioration effect of SP on obesity induced by HFD and to reveal its mechanism of gut microbiota and its metabolites. Results showed that 12-week SP (0.1%, w/w) dietary supplementation could significantly reduce body weight gain, serum lipid level and liver triglycerides level in obese mice. Notably, the SP treatment elevated p-AMPKα and PPARα proteins expression stimulated the phosphorylation of ACC1 and inhibited the protein expression of FAS, PPARγ, and CD36 in the mice liver. Further, SP also reorganized the gut microbiome by up-regulating the proportion of Muribaculaceae_unclassified, Bifidobacterium, Rikenellaceae_RC9_gut_group, Alistipes, and Bacteroides, and down-regulating the abundance of Lactobacillus, Firmicutes_unclassified, Dubosiella Bilophila, and Streptococcus in HFD-induced obese mice. Moreover, the production of microbial metabolites short-chain fatty acids (SCFAs) in feces has also increased. In addition, correlation analysis results showed that obesity-ameliorating effects of SP were highly associated with levels of SCFAs in feces. Therefore, the regulation of SP on liver lipid metabolism may be due to the variation of the gut microbiome and raised production of SCFAs. These results indicate that SP could play the part of a potential nutraceutical for ameliorating obesity through regulation of the gut-liver axis.

Evolution in the Bacillaceae

The family Bacillaceae constitutes a phenotypically diverse and globally ubiquitous assemblage of bacteria. Investigation into how evolution has shaped, and continues to shape, this family has relied on several widely ranging approaches from classical taxonomy, ecological field studies, and evolution in soil microcosms to genomic-scale phylogenetics, laboratory, and directed evolution experiments. One unifying characteristic of the Bacillaceae , the endospore, poses unique challenges to answering questions regarding both the calculation of evolutionary rates and claims of extreme longevity in ancient environmental samples.

Virgibacillus natechei sp. nov., a moderately halophilic bacterium isolated from sediment of a saline lake in southwest of Algeria

A novel, Gram-positive, moderately halophilic bacterium, oxidase- and catalase-positive designated FarD(T) was isolated from sediments of a saline lake located in Taghit, 93 km from Bechar, southwest of Algeria. Cells were rod-shaped, endospore forming, and motile. Growth occurred at 15-40 °C (optimum, 35 °C), pH 6.0-12.0 (optimum, 7.0) and in the presence of 1-20 % NaCl (optimum, 10 %). Strain FarD(T) used glucose, mannitol, melibiose, D-mannose, and 5 ketogluconate. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, and three phospholipids; MK-7 is the predominant menaquinone. The predominant cellular fatty acids were anteiso C15:0, anteiso C17:0, C20:0, and anteiso C19:0. The DNA G+C content was 42.1 mol%. Phylogenetic analysis of the small-subunit ribosomal RNA gene sequence indicated that strain FarD(T) had as its closest relative Virgibacillus salinus (similarity of 96.3 %). Based on phenotypic, phylogenetic, and taxonomic characteristics, strain FarD(T) is proposed as a novel species of the genus Virgibacillus within the order Clostridiales, for which the name V. natechei is proposed. The type strain is FarD(T) (=DSM 25609(T) = CCUG 62224(T)).

Virgibacillus campisalis sp. nov., from a marine solar saltern

A Gram-staining-variable, motile, endospore-forming and rod-shaped bacterial strain, IDS-20(T), was isolated from a marine solar saltern in Korea and subjected to a polyphasic taxonomic investigation. Strain IDS-20(T) grew optimally at 37 °C, at pH 7.5-8.0 and in the presence of 4-5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain IDS-20(T) belongs to the genus Virgibacillus. Strain IDS-20(T) exhibited 93.4-96.6 % 16S rRNA gene sequence similarity to the type strains of species of the genus Virgibacillus. Strain IDS-20(T) had MK-7 as the predominant menaquinone and a cell-wall peptidoglycan based on meso-diaminopimelic acid. The major fatty acids were anteiso-C(15 : 0) and anteiso-C(17 : 0) and major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and two unidentified phospholipids. The DNA G+C content was 39.5 mol%. The phylogenetic distinctiveness and differential phenotypic characteristics of strain IDS-20(T) demonstrated that this strain can be distinguished from recognized species of the genus Virgibacillus. On the basis of the data presented, strain IDS-20(T) represents a novel species of the genus Virgibacillus, for which the name Virgibacillus campisalis sp. nov. is proposed. The type strain is IDS-20(T) ( = KCTC 13727(T)  = CCUG 59308(T)).

Virgibacillus alimentarius sp. nov., isolated from a traditional Korean food

A novel, Gram-positive, rod-shaped, motile, endospore-forming, halophilic bacterial strain, J18(T), was isolated from a traditional salt-fermented seafood made of gizzard shad in Korea. Colonies were convex, cream-coloured and 1.0-2.0 mm in diameter after incubation for 3 days on marine agar. Growth occurred at pH 7.0-11.0 (optimum, pH 10.0), at 4-40 °C (optimum, 37 °C) and in the presence of 0-30% NaCl (optimum, 9-10%). On the basis of 16S rRNA gene sequence analysis, strain J18(T) was related most closely to Virgibacillus byunsanensis ISL-24(T) (96.3% similarity), Virgibacillus carmonensis LMG 20964(T) (96.2%), Virgibacillus halodenitrificans DSM 10037(T) (96.0%), Virgibacillus arcticus Hal 1(T) (95.5%) and Virgibacillus necropolis LMG 19488(T) (95.5%). The major fatty acids were anteiso-C(15:0) and anteiso-C(17:0). The DNA G+C content of strain J18(T) was 37.0 mol%. The cell-wall peptidoglycan was of the meso-diaminopimelic acid type. The major quinone was menaquinone 7 (MK-7). Based on phenotypic, chemotaxonomic and phylogenetic data, strain J18(T) is considered to represent a novel species of the genus Virgibacillus, for which the name Virgibacillus alimentarius sp. nov. is proposed. The type strain is J18(T) (=KACC 14624(T) =JCM 16994(T)).