Bacteroides vulgatus attenuates experimental mice colitis through modulating gut microbiota and immune responses.

Introduction: Bacteroides vulgatus is one of the predominant Bacteroides species in the human gut and exerts a series of beneficial effects. The aim of this study was to investigate the protective role of B. vulgatus Bv46 in a dextran sodium sulfate (DSS) induced colitis mouse model. Methods: Female C57BL/6J mice were given 3% DSS in drinking water to induce colitis and simultaneously treated with B. vulgatus Bv46 by gavage for 7 days. Daily weight and disease activity index (DAI) of mice were recorded, and the colon length and histological changes were evaluated. The effects of B. vulgatus Bv46 on gut microbiota composition, fecal short chain fatty acids (SCFAs) concentration, transcriptome of colon, colonic cytokine level and cytokine secretion of RAW 264·7 macrophage cell line activated by the lipopolysaccharide (LPS) were assessed. Results and Discussion: B. vulgatus Bv46 significantly attenuated symptoms of DSS-induced colitis in mice, including reduced DAI, prevented colon shortening, and alleviated colon histopathological damage. B. vulgatus Bv46 modified the gut microbiota community of colitis mice and observably increased the abundance of Parabacteroides, Bacteroides, Anaerotignum and Alistipes at the genus level. In addition, B. vulgatus Bv46 treatment decreased the expression of colonic TNF-α, IL-1ß and IL-6 in DSS-induced mouse colitis in vivo, reduced the secretion of TNF-α, IL-1ß and IL-6 in macrophages stimulated by LPS in vitro, and downregulated the expression of Ccl19, Cd19, Cd22, Cd40 and Cxcr5 genes in mice colon, which mainly participate in the regulation of B cell responses. Furthermore, oral administration of B. vulgatus Bv46 notably increased the contents of fecal SCFAs, especially butyric acid and propionic acid, which may contribute to the anti-inflammatory effect of B. vulgatus Bv46. Supplementation with B. vulgatus Bv46 serves as a promising strategy for the prevention of colitis.

Nocardioides ochotonae sp. nov., Nocardioides campestrisoli sp. nov. and Nocardioides pantholopis sp. nov., isolated from the Qinghai-Tibet Plateau.

Six Gram-stain-positive, aerobic and irregular-rod-shaped actinobacteria (ZJ1313T, ZJ1307, MC1495T, Y192, 603T and X2025) were isolated from the Qinghai-Tibet Plateau of China and were characterized using a polyphasic taxonomic method. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the six new strains formed three distinct clusters within the genus Nocardioides, and strains ZJ1313T and ZJ1307 were most closely related to N. solisilvae JCM 31492T (16S rRNA gene sequence similarity, 98.0 %), MC1495T and Y192 to N. houyundeii 78T (98.5 %), and 603T and X2025 to N. dokdonensis JCM 14815T (97.6 %). The digital DNA-DNA hybridization values of strains ZJ1313T, MC1495T and 603T among each other and with type strains of their closest relatives were all below the 70 % cut-off point, but values within each pair of new strains were all higher than the threshold. The major fatty acids of these strains were iso-C16 : 0, C17 : 1 ω8c or C18 : 1 ω9c. MK-8(H4) was the predominant respiratory menaquinone and ʟʟ-2,6-diaminopimelic acid was the diagnostic diamino acid. All the strains shared diphosphatidylglycerol (predominant), phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol as the common polar lipids, with minor difference in the types of unidentified phospholipids, glycolipids and lipids. The G+C contents based on genomic DNA of strains ZJ1313T, MC1495T and 603T were 72.5, 72.1 and 73.2 mol%, respectively. The above results suggested that strain pairs ZJ1313T/ZJ1307, MC1495T/Y192 and 603T/X2025 represent three new species of genus Nocardioides, for which the names Nocardioides ochotonae sp. nov. (ZJ1313T=GDMCC 4.177T=KCTC 49537T=JCM 34185T), Nocardioides campestrisoli sp. nov. (MC1495T=GDMCC 4.176T=KCTC 49536T=JCM 34307T) and Nocardioides pantholopis sp. nov. (603T=CGMCC 4.7510T=DSM 106494T) are proposed accordingly.

Identification of Haloactinobacterium kanbiaonis sp. nov. and Ruania zhangjianzhongii sp. nov., two novel species of the family Ruaniaceae isolated from faeces of bats (Hipposideros spp.).

Two pairs of aerobic, Gram-stain-positive, rod-shaped strains (HY164T/HY044, HY168T/HY211) were isolated from bat faecal samples. Strains HY164T and HY044 were motile with a polar flagellum, and had 16S rRNA gene similarity of 95.1-98.6 % to Haloactinobacterium album YIM 93306T and Haloactinobacterium glacieicola T3246-1T; strains HY168T and HY211 were most similar to Ruania albidiflava DSM 18029T (96.6 %). Phylogenetic trees based on 16S rRNA gene and whole genome sequences revealed affiliation of strains HY164T and HY168T to the family Ruaniaceae, representing novel lineages in the genera Haloactinobacterium and Ruania, respectively, which was also supported by the results for average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH). For all isolates, the principal cellular fatty acids were anteiso-C15 : 0 and iso-C14 : 0. HY164T and HY168T had MK-8(H4) as the predominant isoprenoid quinone, diphosphatidylglycerol, phosphatidylglycerol, several unidentified phospholipids and glycolipids as common polar lipids while the latter strain additionally contained one unidentified aminophospholipid and one unidentified phosphoglycolipid. Besides sharing alanine, glutamic acid and lysine with HY164T, HY168T additionally contained 2,4-diaminobutyric acid in the cell-wall peptidoglycan. The whole-cell sugars of HY164T were ribose and rhamnose, while HY168T only included the latter. The DNA G+C contents of HY164T and HY168T were 71.0 and 69.1 mol%, respectively. Combining the polyphasic taxonomic data, HY164T (=CGMCC 4.7606T=JCM 33464T) is classified as representing a novel species of the genus Haloactinobacterium with the proposed name Haloactinobacterium kanbiaonis sp. nov., and HY168T (=CGMCC 1.16970T=JCM 33465T) is proposed to represent a novel species of the genus Ruania with the name Ruania zhangjianzhongii sp. nov.

Microbacterium chengjingii sp. nov. and Microbacterium fandaimingii sp. nov., isolated from bat faeces of Hipposideros and Rousettus species.

Four aerobic, Gram-stain-positive, rod-shaped bacteria (HY60T, HY54, HY82T and HY89) were isolated from bat faeces of Hipposideros and Rousettus species collected in PR China. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the four novel strains formed two separate but adjacent subclades close to Microbacterium agarici CGMCC 1.12260T (97.6-97.7 % similarity), Microbacterium humi JCM 18706T (97.3-97.5 %) and Microbacterium lindanitolerans JCM 30493T (97.3-97.4 %). The 16S rRNA gene sequence similarity was 98.3 % between strains HY60T and HY82T, and identical within strain pairs HY60T/HY54 and HY82T/HY89. The DNA G+C contents of strains HY60T and HY82T were 61.9 and 63.3 mol%, respectively. The digital DNA-DNA hybridization and average nucleotide identity values between each novel strain and their closest relatives were all below the 70 % and 95-96 % thresholds for species delimitation, respectively. All four novel strains contained anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and iso-C15 : 0 as the main fatty acids, MK-11 and MK-12 as the major respiratory quinones, and diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid as the predominant polar lipids. The cell-wall peptidoglycan was of B type and contained alanine, glutamate, glycine and ornithine. The acyl type of the muramic acid was glycolyl. The whole-cell sugars were rhamnose and ribose. Based on the foregoing polyphasic analyses, it was concluded that the four uncharacterized strains represented two novel species of the genus Microbacterium, for which the names Microbacterium chengjingii sp. nov. [type strain HY60T (=CGMCC 1.17468T=GDMCC 1.1951T=KACC 22102T)] and Microbacterium fandaimingii sp. nov. [type strain HY82T (=CGMCC 1.17469T=GDMCC 1.1949T=KACC 22101T)] are proposed, respectively.

Maternal doubled haploid production in interploidy hybridization between Brassica napus and Brassica allooctaploids.

MAIN CONCLUSION: We found a new in vivo route to produce maternal doubled haploid of Brassica napus . The pollen donor, an allooctaploid rapeseed, acts as a DH inducer. Inbred line has a powerful advantage in cultivar breeding and genetic analysis. Compared to the traditional breeding methods, doubled haploid production can save years off the breeding process. Though genotype-dependent tissue culture methods are widely used in the Brassica crops, seed-based in vivo doubled haploid developing systems are rare in nature and in the laboratory. As interspecific cross and interploid hybridization play an important role in genome evolution and plant speciation, we created a new Brassica artificial hybrid, a Brassica allooctaploid (AAAACCCC, 2n = 8× = 76), by interspecific crossing and genome doubling. A homozygous line was observed at the third self-generation of a synthesized Brassica allohexaploid (AAAACC, 2n = 6× = 58). Crosses between B. napus as female and Brassica allooctaploid as pollen donor were conducted, which yielded maternal doubled haploid B. napus that were identified based on phenotype, ploidy, and molecular analysis. The Brassica octaploid acted as a maternal doubled haploid inducer and had a relatively high induction rate. Our research provides a new insight for generation of homozygous lines in vivo using a single-step approach, as well as promotes the understanding in breeding programs and genetic studies involving the Brassicas.