Acutalibacter caecimuris sp. nov., Acutalibacter intestini sp. nov. and Neglectibacter caecimuris sp. nov., three novel species of the family Oscillospiraceae isolated from caecal contents of C57BL/6J mice.

The intestines of mice are colonized by diverse, as-yet-uncultivated bacteria. In this report, we describe the isolation, culture, genotypic and phenotypic characterization, as well as taxonomic classification of three novel anaerobic bacterial strains derived from the caecal contents of C57BL/6J male mice. According to the phenotypic and genotype-based polyphasic taxonomy, we propose three novel species within the family Oscillospiraceae. They are Acutalibacter caecimuris sp. nov. (type strain M00118T=CGMCC 1.18042T=KCTC 25739T), Acutalibacter intestini sp. nov. (type strain M00204T=CGMCC 1.18044T=KCTC 25741T) and Neglectibacter caecimuris sp. nov. (type strain M00184T=CGMCC 1.18043T=KCTC 25740T).

Effects of Sichuan pepper (huajiao) powder on disease activity and caecal microbiota of dextran sodium sulphate-induced inflammatory bowel disease mouse model.

BACKGROUND: Sichuan pepper [Zanthoxylum bungeanum; huajiao (HJ)] is a widely used spice in China and has better antioxidative, anti-glycation, and bile acid-lowering properties than cumin and coriander seeds. HJ affects inflammation-related cytokines and caecal microbiota in mice fed a low-fibre and high-sucrose diet. METHODS AND RESULTS: To determine the ameliorative effect of HJ on inflammatory bowel disease, C57BL/6 mice were divided into three groups and fed distilled water (control) or 3% (w/v) dextran sodium sulphate (DSS) in drinking water with normal chow containing 0% or 5% (w/w) HJ powder for seven days. After 6 days of feeding, diarrhoea, decreased body weight, and blood in faeces were observed in the DSS group. DSS treatment increased the spleen weight and damaged the colon tissue. These inflammatory indices were inhibited by HJ treatment. Amplicon sequencing of the 16S rDNA (V4) gene of the caecal content revealed a decrease in the alpha diversity (Simpson index D) in the DSS treatment group compared to the control group. The abundance of caecal Desulfovibrio, an inflammation-related genus, was higher and the caecal Lachnospiraceae and Bacteroides levels were lower in the DSS-treated mice than those in the control mice. However, HJ suppressed the DSS-induced changes in the caecal microbiota. CONCLUSION: HJ intake contributes to the reduction in inflammation and maintenance of the gut microbiota. However, the strong antioxidant properties of phenolic compounds and fermentability of water-soluble dietary fibres in HJ and their relationship with other functional properties warrant further investigation.

Amygdalobacter indicium gen. nov., sp. nov., and Amygdalobacter nucleatus sp. nov., gen. nov.: novel bacteria from the family Oscillospiraceae isolated from the female genital tract.

Four obligately anaerobic Gram-positive bacteria representing one novel genus and two novel species were isolated from the female genital tract. Both novel species, designated UPII 610-JT and KA00274T, and an additional isolate of each species were characterized utilizing biochemical, genotypic and phylogenetic analyses. All strains were non-motile and non-spore forming, asaccharolytic, non-cellulolytic and indole-negative coccobacilli. Fatty acid methyl ester analysis for UPII 610-JT and KA00274T and additional isolates revealed C16 : 0, C18 : 0, C18:1ω9c and C18:2ω6,9c to be the major fatty acids for both species. UPII 610-JT had a 16S rRNA gene sequence similarity of 99.4 % to an uncultured clone sequence (AY724740) designated as Bacterial Vaginosis Associated Bacterium 2 (BVAB2). KA00274T had a 16S rRNA gene sequence similarity of 96.5 % to UPII 610-JT. Whole genomic DNA mol% G+C content was 42.2 and 39.3 % for UPII 610-JT and KA00274T, respectively. Phylogenetic analyses indicate these isolates represent a novel genus and two novel species within the Oscillospiraceae family. We propose the names Amygdalobacter indicium gen. nov., sp. nov., for UPII 610-JT representing the type strain of this species (=DSM 112989T, =ATCC TSD-274T) and Amygdalobacter nucleatus gen. nov., sp. nov., for KA00274T representing the type strain of this species (=DSM 112988T, =ATCC TSD-275T).

Thermocaproicibacter melissae gen. nov., sp. nov., a thermophilic chain-elongating bacterium, producing n-caproate from polymeric carbohydrates.

Strain MDTJ8T is a chain-elongating thermophilic bacterium isolated from a thermophilic acidogenic anaerobic digestor treating human waste while producing the high commodity chemical n-caproate. The strain grows and produces formate, acetate, n-butyrate, n-caproate and lactate from mono-, di- and polymeric saccharides at 37-60 °C (optimum, 50-55 °C) and at pH 5.0-7.0 (optimum, pH 6.5). The organism is an obligate anaerobe, is motile and its cells form rods (0.3-0.5×1.0-3.0 µm) that stain Gram-positive and occur primarily as chains. Phylogenetic analysis of both the 16S rRNA gene and full genome sequence shows that strain MDTJ8T belongs to a group that consists of mesophylic chain-elongating bacteria within the family Oscillospiraceae, being nearest to Caproicibacter fermentans EA1T (94.8 %) and Caproiciproducens galactitolivorans BS-1T (93.7 %). Its genome (1.96 Mbp) with a G+C content of 49.6 mol% is remarkably smaller than those of other chain-elongating bacteria of the family Oscillospiraceae. Pairwise average nucleotide identity and DNA-DNA hybridization values between strain MDJT8T and its mesophilic family members are less than 70 and 35 %, respectively, while pairwise average amino acid identity values are less than 68 %. In addition, strain MDJT8T uses far less carbohydrate and non-carbohydrate substrates compared to its nearest family members. The predominant cellular fatty acids of strain MDTJ8T are C14 : 0, C14 : 0 DMA (dimethyl acetal) and C16 : 0, while its polar lipid profile shows three unidentified glycophospholipids, 11 glycolipids, 13 phospholipids and six unidentified lipids. No respiratory quinones and polyamines are detected. Based on its phylogenetic, genotypic, morphological, physiological, biochemical and chemotaxonomic characteristics, strain MDTJ8T represents a novel species and novel genus of the family Oscillospiraceae and Thermocaproicibacter melissae gen. nov., sp. nov. is proposed as its name. The type strain is MDTJ8T (=DSM 114174T=LMG 32615T=NCCB 100883T).

Caproicibacterium lactatifermentans sp. nov., isolated from pit clay used for the production of Chinese strong aroma-type liquor.

Two recently reported bacterial strains that were identified as the dominant caproate-producing bacteria in pit clay, were further characterized to determine their phylogeny and taxonomy. The two strains, designated as LBM19010T and JNU-WLY1368, were short rod-shaped, Gram-stain-positive, non-motile and strictly anaerobic. Analysis of the 16S rRNA gene sequences revealed that strains LBM19010T and JNU-WLY1368 shared a 16S rRNA gene sequence similarity of 99.93 % and belonged to a recent proposed genus Caproicibacterium in the family Oscillospiraceae. The proposed type strain, LBM19010T, showed the highest 16S rRNA gene sequence similarity to Caproicibacterium amylolyticum LBM18003T (96.34%), followed by Caproiciproducens galactitolivorans JCM 30532T (94.14 %). The pairwise average nucleotide identity and average amino acid identity values between strains LBM19010T and LBM18003T were 74.84 and 76.18 %, respectively. Growth of strain LBM19010T occurred at pH 4.5-7.5 (optimum, pH 5.0-5.5), 20-40 °C (optimum, 35 °C) and with 0-1 % (w/v) NaCl (optimum, 0 %). Strains LBM19010T and JNU-WLY1368 were both able to ferment several hexoses, disaccharides, starch and lactate but not pentoses. Caproate and butyrate were the major end-products from glucose. The predominant cellular fatty acids (>10 %) of strain LBM19010T were C16 : 0 (56.3 %), C14 : 0 DMA (19.5 %) and C14 : 0 (14.9 %). The identified polar lipids of strain LBM19010T were diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids and nine unidentified glycolipids. Based on phylogenetic, phenotypic and chemotaxonomic evidence, strains LBM19010T and JNU-WLY1368 belong to a novel species of the genus Caproicibacterium, for which the name Caproicibacterium lactatifermentans sp. nov. is proposed. The type strain is LBM19010T (=GDMCC 1.1627T=JCM 33782T).

Neglectibacter timonensis gen. nov., sp. nov. and Scatolibacter rhodanostii gen. nov., sp. nov., two anaerobic bacteria isolated from human stool samples.

Strains Marseille-P2265T (=CSUR P2265T =DSM 102082 T) and Marseille-P3890T (=CSUR P3890T =CCUG 72341 T) were isolated from stool samples using the culturomics approach. The 16S rRNA gene sequences of both strains were sequenced and compared by BLASTn to the NCBI database. Strains Marseille-P2265T and Marseille-P3890T were most closely related to Acutalibacter muris with identities of 94.3% and 91.5%, respectively. Between the two strains, the 16S rRNA gene sequence identity was 91.5%. Both strains are anaerobic Gram-positive, oxidase- and catalase-negative. The major fatty acid methyl esters (> 10%) in both strains are C16:0 and anteiso-C15:0. Additionally, strain Marseille-P2265T has iso-C15:0 and C14:0, and strain Marseille-P3890T, iso-C14:0. Strain Marseille-P2265T has a genome size of 3,671,396-bp with a G + C content of 52.8%. As for strain Marseille-P3890T, the genome is 2,702,024-bp-long with a 39.8% G + C content. The genomic comparison of closely related species with strains Marseille-P2265T and Marseille-P3890T showed that all digital DNA-DNA hybridization (dDDH), orthologous average nucleotide identity (OrthoANI) and average amino acid identity (AAI) values were lower than the published species thresholds (70% for dDDH, 95-96% for OrthoANI/AAI). Based on these results, it was concluded that strains Marseille-P2265T and Marseille-P3890T belong to two new genera in the family Oscillospiraceae. For these two genera, the names Neglectibacter gen. nov. and Scatolibacter gen. nov. were proposed, with strains Marseille-P2265T and Marseille-P3890T being the type strains of Neglectibacter timonensis gen. nov., sp. nov. and Scatolibacter rhodanostii gen. nov., sp. nov., respectively.

Caproicibacterium amylolyticum gen. nov., sp. nov., a novel member of the family Oscillospiraceae isolated from pit clay used for making Chinese strong aroma-type liquor.

An anaerobic, Gram-stain-positive, rod-shaped, motile and spore-forming bacterium, designated strain LBM18003T, was isolated from pit clay used for making Chinese strong aroma-type liquor. Growth occurred at 20-40 °C (optimum, 30-37 °C), pH 4.5-9.5 (optimum, pH 6.5-7.0) and in the presence of 0.0-1.0 % (w/v) sodium chloride (optimum, 0 %). The predominant fatty acids were C16:0, C14:0, C14:0 DMA and C16:0 3-OH, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two unidentified phospholipids and nine unidentified glycolipids. Phylogenetic analysis revealed that strain LBM18003T is a novel member of the family Oscillospiraceae. The 16S rRNA gene sequence similarities of strain LBM18003T to its two most closely related species were less than 94.5 % for distinguishing genera, i.e. closely related to Caproiciproducens galactitolivorans JCM 30532T (94.1 %) and Caproicibacter fermentans DSM 107079T (93.2 %). The genome size of strain LBM18003T was 2 996 201 bp and its DNA G+C content was 48.48 mol%. Strain LBM18003T exhibited 67.8 and 68.1% pairwise-determined whole-genome average nucleotide identity values to Caproiciproducens galactitolivorans JCM 30532T and Caproicibacter fermentans DSM 107079T, respectively; and showed 62.2 and 61.0 % the average amino acid identity values to Caproiciproducens galactitolivorans JCM 30532T and Caproicibacter fermentans DSM 107079T, respectively; and demonstrated 46.1 and 41.5 % conserved genes to Caproiciproducens galactitolivorans JCM 30532T and Caproicibacter fermentans DSM 107079T, respectively. The comparisons of 16S rRNA gene and genome sequences confirmed that strain LBM18003T represented a novel genus of the family Oscillospiraceae. Based on morphological, physiological, biochemical, chemotaxonomic, genotypic and phylogenetic results, strain LBM18003T represents a novel species of a novel genus of the family Oscillospiraceae, for which the name Caproicibacterium amylolyticum gen. nov., sp. nov. is proposed. The type strain is LBM18003T (=GDMCC 1.1626T=JCM 33783T).

Dysosmobacter welbionis gen. nov., sp. nov., isolated from human faeces and emended description of the genus Oscillibacter.

A strictly anaerobic, Gram-stain-negative, non-spore-forming, non-motile, non-pigmented bacterium, strain J115T, was isolated from human faeces. Cells of strain J115T were straight rods, generally 1.8-3.0 µm, but could be up to 18 µm long. Growth occurred below 2 % (w/v) NaCl and 2 % (v/v) bile. Strain J115T produced acid from myo-inositol but not from d-glucose, d-ribose or d-xylose. Butyric acid was the major end-product from myo-inositol. The genomic DNA G+C content was 58.92 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the closest cultivated neighbours of strain J115T were Oscillibacter ruminantium GH1T (95.4 % similarity) and Oscillibacter valericigenes Sjm18-20T (94.1 %). Strain J115T was also related to the not-yet-cultured bacterium Oscillospira guilliermondii(92-93 % similarity). Coherently with the 16S rRNA gene sequence results, the ANI scores don't have units of strain J115T to O. ruminantium GH1T and O. valericigenes Sjm18-20T were 73.37 and 73.24, respectively, while in silico estimations of DNA-DNA hybridization were both 20.4 %, with confidence intervals of 18.2-22.9 % and 18.2-22.8 %, respectively. The major fatty acids were iso-C15 : 0 (24.2 %), C18 : 0 DMA (18.4 %), anteiso-C15 : 0 (15.2 %) and C16 : 0 DMA (7.6 %). No respiratory quinone was detected. Based on phenotypic features and phylogenetic position, it is proposed that this isolate represents a novel species in a new genus, Dysosmobacter welbionis gen. nov., sp. nov. The type strain of Dysosmobacter welbionis is J115T (DSM 106889T=LMG 30601T).

The effect of Phyllanthus emblica (Amla) fruit supplementation on the rumen microbiota and its correlation with rumen fermentation in dairy cows.

Introduction: Medicinal plants, rich in phytochemicals like phenolic acids, flavonoids, and tannins, offer potential benefits in enhancing productivity, quality, and animal health. Amla fruit (Phyllanthus emblica) is one such plant with promising attributes. This study aimed to investigate the impact of fresh Amla fruit (FAF) supplementation on ruminal microbial composition and its correlation with rumen fermentation in lactating dairy cows. Methods: The study employed a repeated crossover design involving eight ruminally cannulated mid-lactation Holstein dairy cows. Animals received varying levels of fresh Amla fruit supplementation (0, 200, 400, and 600 g/d). Results: When 400 g/d of FAF was added to the diet, there was a significant increase in the relative abundance of Firmicutes (p = 0.02). However, at 200 g/d, the relative abundance of ruminal Bacteroidota was higher than the 0 and 400 g/d FAF supplementation (p < 0.01). LEfSe analysis identified distinct taxa, such as Clostridia vadinBB60 in the 200 g/d group, Oscillospiraceae in the 400 g/d group, and Elusimicrobium in the 600 g/d group. Notably, the random forest species abundance statistics identified Oscillospiraceae V9D2013 as a biomarker related to milk yield. Oscillospiraceae, Bacilli RF39, norank_f Prevotellaceae, and Bifidobacterium were positively correlated with ruminal total VFA and molar proportion of propionate, while Rikenellaceae RC9 gut group and Clostridia vadinBB60 were negatively correlated. Discussion: FAF supplementation affects the abundance of beneficial microbes in a dose-dependent manner, which can improve milk yield, efficiency, rumen health, desirable fatty acids, and animal health.

Gut microbiome diversity within Clostridia is negatively associated with human obesity.

Clostridia are abundant in the human gut and comprise families associated with host health such as Oscillospiraceae, which has been correlated with leanness. However, culturing bacteria within this family is challenging, leading to their detection primarily through 16S rRNA amplicon sequencing, which has a limited ability to unravel diversity at low taxonomic levels, or by shotgun metagenomics, which is hindered by its high costs and complexity. In this cross-sectional study involving 114 Colombian adults, we used an amplicon-based sequencing strategy with alternative markers-gyrase subunit B (gyrB) and DNA K chaperone heat protein 70 (dnaK)-that evolve faster than the 16S rRNA gene. Comparing the diversity and abundance observed with the three markers in our cohort, we found a reduction in the diversity of Clostridia, particularly within Lachnospiraceae and Oscillospiraceae among obese individuals [as measured by the body mass index (BMI)]. Within Lachnospiraceae, the diversity of Ruminococcus_A negatively correlated with BMI. Within Oscillospiraceae, the genera CAG-170 and Vescimonas also exhibited this negative correlation. In addition, the abundance of Vescimonas was negatively correlated with BMI. Leveraging shotgun metagenomic data, we conducted a phylogenetic and genomic characterization of 120 metagenome-assembled genomes from Vescimonas obtained from a larger sample of the same cohort. We identified 17 of the 72 reported species. The functional annotation of these genomes showed the presence of multiple carbohydrate-active enzymes, particularly glycosyl transferases and glycoside hydrolases, suggesting potential beneficial roles in fiber degradation, carbohydrate metabolism, and butyrate production. IMPORTANCE: The gut microbiota is diverse across various taxonomic levels. At the intra-species level, it comprises multiple strains, some of which may be host-specific. However, our understanding of fine-grained diversity has been hindered by the use of the conserved 16S rRNA gene. While shotgun metagenomics offers higher resolution, it remains costly, may fail to identify specific microbes in complex samples, and requires extensive computational resources and expertise. To address this, we employed a simple and cost-effective analysis of alternative genetic markers to explore diversity within Clostridia, a crucial group within the human gut microbiota whose diversity may be underestimated. We found high intra-species diversity for certain groups and associations with obesity. Notably, we identified Vescimonas, an understudied group. Making use of metagenomic data, we inferred functionality, uncovering potential beneficial roles in dietary fiber and carbohydrate degradation, as well as in short-chain fatty acid production.