Small intestinal microbiota composition altered in obesity-T2DM mice with high salt fed

Obesity has become a global concern because of increasing the risk of many diseases. Alterations in human gut microbiota have been proven to be associated with obesity, yet the mechanism of how the microbiota are altered by high salt diet (HSD) remains obscure. In this study, the changes of Small Intestinal Microbiota (SIM) in obesity-T2DM mice were investigated. High-throughput sequencing was applied for the jejunum microbiota analysis. Results revealed that high salt intake (HS) could suppress the body weight (B.W.) in some extent. In addition, significant T2DM pathological features were revealed in high salt-high food diet (HS-HFD) group, despite of relatively lower food intake. High-throughput sequencing analysis indicated that the F/B ratio in HS intake groups increased significantly (P < 0.001), whereas beneficial bacteria, such as lactic acid or short chain fatty acid producing bacteria, were significantly decreased in HS-HFD group (P < 0.01 or P < 0.05). Furthermore, Halorubrum luteum were observed in small intestine for the first time. Above results preliminary suggested that in obesity-T2DM mice, high dietary salt could aggravate the imbalance of composition of SIM to unhealthy direction.

Aquaticitalea lipolytica gen. nov., sp. nov., isolated from Antarctic seawater

A Gram-stain-negative, rod-shaped bacterium, designated Ar-125^T, was isolated from Antarctic seawater. It produced carotenoid-like pigments and did not produce Bchl a. Ar-125^T was positive for hydrolysis of DNA, aesculin, gelatin, starch, Tween 40 and Tween 60. The sole respiratory quinone was MK-6. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, one unidentified glycolipid and two unidentified lipids. The principal fatty acids were branched-chain fatty acids, including iso-C15 : 0, iso-C15 : 1 G, summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), iso-C16 : 0, iso-C17 : 0 3-OH, iso-C16 : 0 3-OH and iso-C15 : 0 3-OH, as well as C15 : 0. The genomic DNA G+C content was 31.8 mol%. On the basis of 16S rRNA gene sequence analysis, Ar-125^T is closely related to the species of the genera Bizionia(with 16S rRNA gene pairwise sequence similarity of 93.7-96.5 %), Formosa(94.3-95.8 %), Gaetbulibacter(94.2-95.7 %), Geojedonia(95.5 %), Gelidibacter (93.3-95.4 %), Meridianimaribacter(95.3 %) and Psychroserpens (94.8-95.3 %), of the family Flavobacteriaceae. Phylogenetic analysis indicated that it represented an independent lineage and that the closest relatives were members of the genus Gelidibacter. Differential phenotypic properties and chemotaxonomic differences, together with phylogenetic distinctiveness, revealed that Ar-125^T could be differentiated from members of closely related genera. Therefore, it is proposed that Ar-125^T represents a novel species in a new genus, for which the name Aquaticitalea lipolytica gen. nov., sp. nov. (type strain Ar-125^T =CGMCC 1.15295^T =JCM 30876^T) is proposed.

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

A Gram-stain-negative, aerobic and slightly halophilic bacterium was isolated from the South China Sea, and was subjected to characterization using a polyphasic taxonomic approach. Cells of the isolate, designated NH83T, were non-motile and rod-shaped. On the basis of 16S rRNA gene sequence analysis, strain NH83Twas closely related to members of the genera Aureisphaera (with sequence similarity of 92.9 %), Jejudonia (92.8 %), Marixanthomonas (92.6 %), Altuibacter (92.6 %), Ulvibacter (91.5-91.9 %), Gilvibacter (91.8 %) and Aequorivita (89.6-91.2 %), all of which belong to the family Flavobacteriaceae. Phylogenetic analysis indicated that it represented an independent lineage and its closest relatives belonged to the genus Marixanthomonas. The sole respiratory quinone was MK-6. The major polar lipids were phosphatidylethanolamine, two aminolipids, one aminophospholipid and one unidentified lipid. The principal fatty acids were branched fatty acids, including iso-C15 : 0, iso-C17 : 0 3-OH, iso-C16 : 0, iso-C15 : 1 G and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c). The genomic DNA G+C content was 41.0 mol%. Strain NH83T was positive for hydrolysis of aesculin, gelatin and Tween 60. Phylogenetic distinctiveness and chemotaxonomic differences, together with differential phenotypic properties, revealed that strain NH83T could be differentiated from closely related genera. Therefore, it is proposed that strain NH83T represents a novel species in a new genus, for which the name Marinirhabdus gelatinilytica gen. nov., sp. nov. (type strain NH83T=CGMCC 1.15462T=DSM 101478T) is proposed.

Haloterrigena saccharevitans sp. nov., an extremely halophilic archaeon from Xin-Jiang, China

A novel extremely halophilic strain, isolated from Aibi salt lake, Xin-Jiang, China, was subjected to polyphasic taxonomic characterization. This strain, designated AB14T, is neutrophilic, motile and requires at least 10 % (w/v) NaCl for growth. Strain AB14T grows at 24–58 °C, with optimal growth at 42–45 °C. Mg2+ is not required, but growth is observed in MgCl2 concentrations as high as 1·0 M. Strain AB14T possesses the diphytanyl (C20C20) and phytanyl-sesterterpanyl diether (C20C25) derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and mannose-2,6 disulfate 1→2 glucose-glycerol diether. The genomic DNA G+C content is 66·6 mol%. The 16S rRNA gene sequence similarity values of strain AB14T with its nearest phylogenetic neighbours (Haloterrigena thermotolerans and Haloterrigena turkmenica) are 98·6 and 96·0 %, respectively. DNA–DNA hybridization revealed 54 % relatedness between strain AB14T and Haloterrigena thermotolerans JCM 11050T and 21 % between strain AB14T and Haloterrigena turkmenica JCM 9101T. It is therefore proposed that strain AB14T represents a novel species, for which the name Haloterrigena saccharevitans sp. nov. is proposed. The type strain is AB14T (=AS 1.3730T=JCM 12889T).

[Analysis of partial sequence of the gene for a novel Br protein]

A strain of halophilic archaeum AB1 was isolated and purified from Aibi Lake located in the north of Xinjiang Uygur Autonomous Region. Partial DNA fragment encoding a bacteriorhodopsin (Br) protein as well as 16S rRNA of AB1 was amplified by PCR, and their nucleotide sequences were determined subsequently. On the basis of homology and phylognetic analysis about 16S rRNA gene (16S rDNA), it could be speculated that the strain AB1 is a novel member of the genus Natronococcus. The hydropathy analysis of Br fragment revealed that the AB1 Br had a transmembrane heptahelical structure similar to that of other Brs. On the other hand, homology alignment using the deduced partial amino acid sequence of Br protein of AB1 with other Br proteins showed that AB1 Br protein is obviously different to others. These facts indicated that the Br in halophilic archaeum AB1 is a new Br protein.