Commensal microbiota are well known to play an important role in antiviral immunity by providing immune inductive signals; however, the consequence of dysbiosis on antiviral immunity remains unclear. We demonstrate that dysbiosis caused by oral antibiotic treatment directly impairs antiviral immunity following viral infection of the vaginal mucosa. Antibiotic-treated mice succumbed to mucosal herpes simplex virus type 2 infection more rapidly than water-fed mice, and also showed delayed viral clearance at the site of infection. However, innate immune responses, including type I IFN and proinflammatory cytokine production at infection sites, as well as induction of virusspecific CD4 and CD8 T-cell responses in draining lymph nodes, were not impaired in antibiotic-treated mice. By screening the factors controlling antiviral immunity, we found that IL-33, an alarmin released in response to tissue damage, was secreted from vaginal epithelium after the depletion of commensal microbiota. This cytokine suppresses local antiviral immunity by blocking the migration of effector T cells to the vaginal tissue, thereby inhibiting the production of IFN-γ, a critical cytokine for antiviral defense, at local infection sites. These findings provide insight into the mechanisms of homeostasis maintained by commensal bacteria, and reveal a deleterious consequence of dysbiosis in antiviral immune defense.commensal microbiota | dysbiosis | IL-33 | herpes simplex virus type 2 | genital tract

Akkermansia muciniphila is widely considered a next-generation beneficial microbe. This bacterium resides in the mucus layer of its host and regulates intestinal homeostasis and intestinal barrier integrity by affecting host signaling pathways. However, it remains unknown how the expression of genes encoding extracellular proteins is regulated in response to dynamic mucosal environments. In this study, we elucidated the effect of mucin on the gene expression and probiotic traits of A. muciniphila . Transcriptome analysis showed that the genes encoding most mucin-degrading enzymes were significantly upregulated in the presence of mucin. By contrast, most genes involved in glycolysis and energy metabolic pathways were upregulated under mucin-depleted conditions. Interestingly, the absence of mucin resulted in the upregulation of 79 genes encoding secreted protein candidates, including Amuc-1100 as well as members of major protein secretion systems. These transcript level changes were consistent with the fact that administration of A. muciniphila grown under mucin-depleted conditions to high-fat diet-induced diabetic mice reduced obesity and improved intestinal barrier integrity more efficiently than administration of A. muciniphila grown under mucin-containing conditions. In conclusion, mucin content in the growth medium plays a critical role in the improvement by A. muciniphila of high-fat diet-induced obesity, intestinal inflammation, and compromised intestinal barrier integrity related to a decrease in goblet cell density. Our findings suggest the depletion of animal-derived mucin in growth medium as a novel principle for the development of A. muciniphila for human therapeutics.

Background The gut microbiota is associated with diverse age-related disorders. Several rejuvenation methods, such as probiotic administration and faecal microbiota transplantation, have been applied to alter the gut microbiome and promote healthy ageing. Nevertheless, prolongation of the health span of aged mice by remodelling the gut microbiome remains challenging. Results Here, we report the changes in gut microbial communities and their functions in mouse models during ageing and three rejuvenation procedures including co-housing, serum-injection and parabiosis. Our results showed that the compositional structure and gene abundance of the intestinal microbiota changed dynamically during the ageing process. Through the three rejuvenation procedures, we observed that the microbial community and intestinal immunity of aged mice were comparable to those of young mice. The results of metagenomic data analysis underscore the importance of the high abundance of Akkermansia and the butyrate biosynthesis pathway in the rejuvenated mouse group. Furthermore, oral administration of Akkermansia sufficiently ameliorated the senescence-related phenotype in the intestinal systems in aged mice and extended the health span, as evidenced by the frailty index and restoration of muscle atrophy. Conclusions In conclusion, the changes in key microbial communities and their functions during ageing and three rejuvenation procedures, and the increase in the healthy lifespan of aged mice by oral administration of Akkermansia. Our results provide a rationale for developing therapeutic strategies to achieve healthy active ageing.

A novel strictly anaerobic strain, ALO17(T), was isolated from mouse faeces and found to produce lactic acid as a major metabolic end product. The isolate was observed to be Gram-stain positive, non-motile, non-spore forming small rods, oxidase and catalase negative, and to form cream-coloured colonies on DSM 104 agar plates. The NaCl range for growth was determined to be 0-2 % (w/v). The isolate was found to grow optimally at 37 °C, with 0.5 % (w/v) NaCl and at pH 7. The cell wall hydrolysates were found to contain ribose as a major sugar. The genomic DNA G+C content was determined to be 52.3 mol%. A phylogenetic analysis of the 16S rRNA gene sequence revealed that Holdemanella biformis DSM 3989(T), Faecalicoccus pleomorphus ATCC 29734(T), Faecalitalea cylindroides ATCC 27803(T), and Allobaculum stercoricanis DSM 13633(T) are closely related to the isolate (87.4, 87.3, 86.9 and 86.9 % sequence similarity), respectively. The major cellular fatty acids (>10 %) of the isolate were identified as C18:1 cis 9 FAME (36.9 %), C16:0 FAME (33.7 %) and C18:0 FAME (13.2 %). In contrast to the tested reference strains, C20:0 FAME (4.0 %) was detected only in strain ALO17(T) whilst C16:0 DMA was absent. The isolate also differed in its substrate oxidation profiles from the reference strains by being positive for D-melibiose and stachyose but negative for N-acetyl-D-galactosamine and 3-methyl-D-glucose. On the basis of polyphasic taxonomic evidence from this study, the isolate is concluded to belong to a novel genus within the family Erysipelothricaceae. We propose the name Faecalibaculum rodentium gen. nov., sp. nov. to accommodate strain ALO17(T) (=KCTC 15484(T) = JCM 30274(T)) as the type strain.

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Three strictly anaerobic, methanogenic strains JH1 T , JH4 and JH8 were isolated from rumen of the Korean native cattle (HanWoo; Bos taurus coreanae) in South Korea. The colonies were circular, opaque, and slightly yellowish. Phylogenetic analyses of 16S rRNA gene and mcrA (encoding a subunit of methyl-coenzyme M reductase) sequences confirmed the affiliation of the novel strains with the Methanobacteriales, and Methanobrevibacter wolinii SH T was the most closely related species. The 16S rRNA gene and mcrA sequence similarities between strains JH1 T , JH4 and JH8 and M. wolinii SH T were 96.2 and 89.0 % respectively, and DNA-DNA hybridization of the isolates and M. wolinii DSM 11976 T showed a 20 % reassociation. Strain JH1 T exhibited 92 % DNA-DNA relatedness with strains JH4 and JH8, and their 16S rRNA gene and mcrA sequences were identical. Cells stained Gram-positive and were non-motile rods, 1.5-1.8 mm long and 0.6 mm wide. The strains were able to use H 2 /CO 2 and formate. The optimum temperature and pH ranges for growth were 37-40 6C and pH 6.5-7.0. The DNA G+C content of strain JH1 T was 28 mol%. Based on data from this study using a polyphasic approach, the three strains represent a novel species of genus Methanobrevibacter, for which the name Methanobrevibacter boviskoreani sp. nov. is proposed. The type strain is JH1 T (5KCTC 4102 T 5JCM 18376 T ).

A strictly anaerobic, Gram-negative, non-spore-forming bacterium, designated GH1T , was isolated from the rumen of Korean native cattle (HanWoo). Cells were straight to slightly curved rods (2.0-4.5 mm long) and were motile by peritrichous flagella. The isolate grew at 30-45 6C (optimum 40 6C), at pH 5.5-6.5 (optimum pH 6.0) and with up to 3.5 % (w/v) NaCl. Strain GH1T produced acid from D-glucose, D-ribose and D-xylose, with butyric acid being the major end product. The genomic DNA G+C content was 54.6 mol%. Based on comparative 16S rRNA gene sequence analysis, strain GH1 T was most closely related to Oscillibacter valericigenes Diverse and competitive micro-organisms inhabit the rumen and belong to three domains: Bacteria, Archaea (methanogens) and Eucarya (protozoa and fungi) (Miron et al., 2001;Pers-Kamczyc et al., 2011). This complex community plays a very important role in the degradation of cellulosic feeds and the supply of nutrients to the host in the form of volatile fatty acids (Kamra, 2005;Van Soest, 1994). The structure and ecology of the whole microbial community in rumen should be more completely understood in order to manipulate rumen fermentation or control the level of bio-emission of methane from ruminants. A number of micro-organisms in rumen are still non-culturable but their individual function could be critical to the ruminal ecosystem (Pers-Kamczyc et al., 2011). Therefore, isolation and characterization of novel rumen micro-organisms should be performed for complete understanding of ruminal ecology.Korean native cattle, 'HanWoo' (Bos taurus coreanae), inhabit in the region of Korea peninsula and produce good-quality meat. Understanding their physiology, nutrition, metabolism and reproduction is of prime importance for the Korean native cattle industry as it is a significant contributor to farming households, the national economy and the security of food stuffs in Korea (Hwang et al., 2000).In our study, we tried to isolate diverse bacteria from the rumen of HanWoo using strictly anaerobic cultivation technique. Fresh rumen fluid (900 ml) was collected 4 h after morning feeding from a ruminally cannulated 1-yearold HanWoo steer fed 4 kg concentrate and 0.5 kg rice straw (dry matter) twice daily at a research farm of Seoul Abbreviation: DMA, dimethylacetal.

The vaginal microbiota may be important for pregnancy prognosis because vaginal dysbiosis during pregnancy appears to be related to preterm birth (PTB) or pregnancy loss. Previous reports have indicated that a Lactobacillus -poor microbial flora in the vagina and intrauterine infection by diverse anaerobes ascending from the vagina are associated with undesirable delivery outcomes. However, no research has involved the use of pyrosequencing analysis to examine vaginal microbiota profiles or their potential associations with high-risk pregnancy in Korean women. Vaginal swabs were collected from 500 Korean women for the identification of community state types (CSTs). Of these, 137 samples were further analyzed using a Roche/454 GS Junior pyrosequencer. Three distinct CSTs were identified based on the dominant vaginal microbes: CST I ( Lactobacillus crispatus dominated), CST III ( Lactobacillus iners dominated), and CST IV (with diverse species of anaerobes). Twelve of the 67 pregnant women had undesirable pregnancy outcomes (four miscarriages and eight PTBs). The dominant microbe in the vaginal microbiota of women who gave birth at full-term was L. crispatus . In contrast, L. iners was the dominant vaginal microbe in women who miscarried. Most ( n = 6/8) vaginal microbiota profiles of women who experienced PTB could be classified as CST IV, with diverse bacteria, including anaerobic vaginal species. The present study provides valuable information regarding the characteristics of the vaginal microbiota of Korean women related to high-risk pregnancy. Investigation of the vaginal microbiotic structure in pregnant Korean women is necessary to enable better prediction of adverse pregnancy outcomes.