Growth of succinate consumer Dialister hominis is supported by Bacteroides thetaiotaomicron.

This study revealed an interaction between the gut commensal bacterium Bacteroides thetaiotaomicron JCM 5827T and asaccharolytic bacterium Dialister hominis JCM 33369T, which uses succinate instead of carbohydrates for growth. D. hominis usually forms extremely small colonies on Brucella blood agar plates. However, when co-cultured with B. thetaiotaomicron, D. hominis grew noticeably and formed larger colonies than those in the single culture, especially near B. thetaiotaomicron colonies. Although D. hominis barely grew in Gifu anaerobic medium broth, adding 1% succinate improved its growth. In the mixed culture, the succinate produced by B. thetaiotaomicron was mostly converted to propionate. This result was consistent with the single culture of D. hominis in the succinate-containing broth and our previous report on Phascolarctobacterium faecium, a succinate-utilizing gut bacterium. Our series of studies suggests that syntrophy within the human gut microbiota occurs via succinate.

Prevotella lacticifex sp. nov., isolated from the rumen of cows.

The genus Prevotella plays an important role in polysaccharide degradation and fermentation in the rumen. To further understand the function of the phylogenetically diverse genus Prevotella, it is necessary to explore the individual characteristics at the species level. In this study, Gram-negative anaerobic bacterial strains isolated from the rumen of Holstein cows were identified. Strain R5019T was classified within the genus Prevotella based on 16S rRNA gene sequence-based phylogenetic analysis. The values of 16S rRNA gene sequence similarity, average nucleotide identity and digital DNA-DNA hybridization between strain R5019T and its phylogenetically nearest species Prevotella multisaccharivorax PPPA20T were 89.8, 82.6, and 29.3 %, respectively. The genome size of R5019T was estimated to be ca. 4.19 Mb with a genomic G+C content of 49.5 mol%. The major cellular fatty acids and menaquinones were C15 : 0 anteiso and C17 : 0 anteiso and MK-11 and MK-12, respectively. Succinate, lactate, malate, acetate and formate were produced as the fermentation end products using glucose. Based on phylogenetic, physiological, biochemical and genomic differences between 11 strains and other phylogenetically related Prevotella species, a novel species, Prevotella lacticifex sp. nov., is proposed within the genus Prevotella. The type strain is R5019T (=JCM 34664T=DSM 112675T).

Adlercreutzia hattorii sp. nov., an equol non-producing bacterium isolated from human faeces.

Two obligately anaerobic, Gram-stain-positive, rod-shaped bacteria were isolated from faecal samples of healthy humans in Japan. 16S rRNA gene sequence analysis indicated that these two strains (8CFCBH1T and 9CBH6) belonged to the genus Adlercreutzia, which is known as an equol-producing bacterium. The closest neighbours of strain 8CFCBH1T were Adlercreutzia equolifaciens subsp. equolifaciens DSM 19450T (98.6%), Adlercreutzia equolifaciens subsp. celatus do03T (98.4%), Adlercreutzia muris WCA-131-CoC-2T (96.6%), Parvibacter caecicola NR06T (96.4%), Adlercreutzia caecimuris B7T (95.3%) and Adlercreutzia mucosicola Mt1B8T (95.3%). The closest relatives to strain 9CBH6 were A. equolifaciens subsp. equolifaciens DSM 19450T (99.8%), A. equolifaciens subsp. celatus do03T (99.6%) and A. muris WCA-131-CoC-2T (96.8%). Strain 8CFCBH1T showed 22.3-53.5% digital DNA-DNA hybridization (dDDH) values with its related species. In addition, the average nucleotide identity (ANI) values between strain 8CFCBH1T and its related species ranged from 75.4 to 93.3%. On the other hand, strain 9CBH6 was considered as A. equolifaciens based on the dDDH and ANI values (>70% dDDH and >95-96% ANI). Strain 9CBH6 showed daidzein-converting activity, as expected from the result of genome analysis. The genome of strain 8CFCBH1T lacked four genes involved in equol production. Growing cells of strain 8CFCBH1T were not capable of converting daidzein. Based on the collected data, strain 8CFCBH1T represents a novel species in the genus Adlercreutzia, for which the name Adlercreutzia hattorii sp. nov. is proposed. The type strain of A. hattorii is 8CFCBH1T (=JCM 34083T=DSM 112284T).

Fecal Microbiota Perspective for Evaluation of Prebiotic Potential of Bamboo Hemicellulose Hydrolysate in Mice: A Preliminary Study.

Bamboo hemicellulose hydrolysate (BHH) may possess antihypercholesterolemic activity; however, this activity requires further comprehensive study to assess the prebiotic mechanisms of BHH in vivo. Here, we used high-throughput 16S rRNA gene sequencing to preliminarily investigate the correlations between BHH and the fecal microbiomes of three groups of mice fed either a normal diet, a high-fat diet, or a high-fat diet supplemented with 5% BHH for 5 weeks. Alpha diversity (within community) was nonsignificant for all groups; however, beta diversity analysis among communities showed that 5% BHH suppressed the significant changes induced by the high-fat diet. The Firmicutes/Bacteroidetes ratio, the family S24-7 within the order Bacteroidales, the family Lachnospiraceae and several cellulolytic taxa were slightly ameliorated in the BHH group. These results indicated that BHH supplementation influenced the gut bacterial community and suppressed the high-fat diet-induced alterations. Additionally, BHH significantly lowered the serum cholesterol levels and fecal pH. Improving short-chain fatty acid production for all of the bacterial communities in the mouse guts may induce this effect. Thus, the prebiotic potential of BHH should be evaluated considering the gut microbial communities and their interactions.

Coprobacter secundus subsp. similis subsp. nov. and Solibaculum mannosilyticum gen. nov., sp. nov., isolated from human feces.

An obligately anaerobic, Gram-stain-negative, rod-shaped bacterium, designated strain 2CBH44T , was isolated from the fecal sample of a healthy Japanese man. This strain was initially assigned as a novel species of the genus Coprobacter based on the 16S rRNA gene sequence similarities compared with other Coprobacter species. The 16S rRNA gene sequence analysis revealed strain 2CBH44T had relatively low 16S rRNA gene sequence similarity (97.5%) to Coprobacter secundus 177T . However, strain 2CBH44T showed 96.9% average nucleotide identity value with C. secundus 177T , indicating that strain 2CBH44T and C. secundus 177T belong to the same species. On the other hand, the digital DNA-DNA hybridization value between strain 2CBH44T and C. secundus 177T was 73.5%, indicating that strain 2CBH44T is a subspecies of C. secundus. Another anaerobic, Gram-stain-variable, rod-shaped bacterium, designated strain 12CBH8T , was also isolated from human feces. Strain 12CBH8T had significantly low 16S rRNA gene sequence similarities (<92.0%) to the validated bacterial species within the family Oscillospiraceae. The percentage of conserved protein values between the genome of strain 12CBH8T and that of the validated related taxa were <50%, suggesting that strain 12CBH8T belongs to a novel genus. On the basis of the collected data, strain 2CBH44T represents a novel subspecies of C. secundus, for which the name Coprobacter secundus subsp. similis subsp. nov. (type strain 2CBH44T = JCM 34079T = DSM 111570T ) is proposed. Strain 12CBH8T represents a novel species of a novel genus, for which the name Solibaculum mannosilyticum gen. nov., sp. nov. (type strain 12CBH8T = JCM 34081T = DSM 111571T ) is proposed.

Complete Genome Sequence of Faecalibacillus intestinalis JCM 34082, Isolated from Feces from a Healthy Japanese Female.

Here, we report the complete genome sequence of Faecalibacillus intestinalis JCM 34082, a member of the family Erysipelotrichaceae that was isolated from feces from a healthy Japanese woman. The genome assembly comprised 2,869,982 bp, with a G+C content of 29.8%.

Stress Response of Mesosutterella multiformis Mediated by Nitrate Reduction.

Bacterial stress responses are closely associated with the survival and colonization of anaerobes in the human gut. Mesosutterella multiformis JCM 32464T is a novel member of the family Sutterellaceae, an asaccharolytic bacterium. We previously demonstrated energy generation via heme biosynthesis, which is coupled with nitrate reductase. Here, physiological and morphological changes in M. multiformis induced by exposure to nitrate were investigated. The ability of M. multiformis to reduce nitrate was determined using a colorimetric assay. A unique morphology was observed during nitrate reduction under anaerobic conditions. The association between nitrate concentration and cell size or cellular fatty acid composition was evaluated. Nitrate-induced responses of M. multiformis were compared to those of related species. An increase in cellular filamentation and the ratio of saturated: unsaturated fatty acids was mediated specifically by nitrate. This indicates a decrease in cell fluidity and low leakage. Furthermore, a similar response was not observed in other related species cultured in the presence of nitrate. Hence, the nitrate-induced stress response in new anaerobes such as M. multiformis was demonstrated. The response could also be involved in the conservation of menaquinones and the maximization of nitrate reduction.

Microbial interaction between the succinate-utilizing bacterium Phascolarctobacterium faecium and the gut commensal Bacteroides thetaiotaomicron.

A large variety of microbes are present in the human gut, some of which are considered to interact with each other. Most of these interactions involve bacterial metabolites. Phascolarctobacterium faecium hardly uses carbohydrates for growth and instead uses succinate as a substrate. This study investigated the growth behavior of the co-culture of the succinate-specific utilizer P. faecium and the succinogenic gut commensal Bacteroides thetaiotaomicron. Succinate production by B. thetaiotaomicron supported the growth of P. faecium and concomitant propionate production via the succinate pathway. The succinate produced was completely converted to propionate. This result was comparable with the monoculture of P. faecium in the medium supplemented with 1% (w/v) succinate. We analyzed the transcriptional response (RNA-Seq) between the mono- and co-culture of P. faecium and B. thetaiotaomicron. Comparison of the expression levels of genes of P. faecium between the mono- and co-cultured conditions highlighted that the genes putatively involved in the transportation of succinate were notably expressed under the co-cultured conditions. Differential expression analysis showed that the presence of P. faecium induced changes in the B. thetaiotaomicron transcriptional pattern, for example, expression changes in the genes for vitamin B12 transporters and reduced expression of glutamate-dependent acid resistance system-related genes. Also, transcriptome analysis of P. faecium suggested that glutamate and succinate might be used as sources of succinyl-CoA, an intermediate in the succinate pathway. This study revealed some survival strategies of asaccharolytic bacteria, such as Phascolarctobacterium spp., in the human gut.

Prevotella hominis sp. nov., isolated from human faeces.

A strictly anaerobic predominant bacterium, designated as strain gm001T, was isolated from a freshly voided faecal sample collected from a healthy Taiwanese adult. Cells were Gram-stain-negative rods, non-motile and non-spore-forming. Strain gm001T was identified as a member of the genus Prevotella, and a comparison of 16S rRNA and hsp60 gene sequences revealed sequence similarities of 98.5 and 93.3 %, respectively, demonstrating that it was most closely related to the type strain of Prevotella copri. Phylogenomic tree analysis indicated that the gm001T cluster is an independent lineage of P. copri DSM 18205T. The average nucleotide identity, digital DNA‒DNA hybridization and average amino acid identity values between strain gm001T and P. copri DSM 18205T were 80.9, 28.6 and 83.8 %, respectively, which were clearly lower than the species delineation thresholds. The species-specific genes of this novel species were also identified on the basis of pan-genomic analysis. The predominant menaquinones were MK-11 and MK-12, and the predominant fatty acids were anteiso-C15 : 0, C15 : 0 and iso-C15 : 0. Acetate and succinate were produced from glucose as metabolic end products. Taken together, the results indicate that strain gm001T represents a novel species of the genus Prevotella, for which the name Prevotella hominis sp. nov. is proposed. The type strain is gm001T (=BCRC 81118T=JCM 33280T).

Lactococcus insecticola sp. nov. and Lactococcus hodotermopsidis sp. nov., isolated from the gut of the wood-feeding lower termite Hodotermopsis sjostedti.

Two strains of lactic acid bacteria, designated Hs20B0-1T and Hs30E4-3T, were isolated from the gut of the damp-wood termite Hodotermopsis sjostedti. These strains were characterized genetically and phenotypically. Strain Hs20B0-1T was related to Lactococcus piscium DSM 6634T showing 96.3 and 84.2 % sequence similarity in 16S rRNA gene and rpoB gene sequences, respectively. Strain Hs30E4-3T was related to Lactococcus plantarum DSM 20686T showing 94.8 and 82.2 % sequence similarity in 16S rRNA gene and rpoB gene sequences, respectively. The 16S rRNA gene sequence similarity between strains Hs20B0-1T and Hs30E4-3T was 95.7 %. Furthermore, genomic comparisons using pairwise average nucleotide identity (ANI) and digital DNA-DNA hybridization (DDH) analyses between strain Hs20B0-1T and L. piscium DSM 6634T resulted in values of 73.5 and 20.1 %, respectively. Strain Hs30E4-3T had 72.8 % ANI similarity and 21.3 % DDH similarity to L. plantarum DSM 20686T. Strains Hs20B0-1T and Hs30E4-3T had 75.4 % ANI similarity and 21.1 % DDH similarity to each other. The cell-wall peptidoglycan types of strains Hs20B0-1T and Hs30E4-3T were A4α, Lys-Asp and A3α, Lys-Thr-Ala, respectively. The two strains, Hs20B0-1T and Hs30E4-3T, are distinguishable from each other and other established Lactococcus species phylogenetically and phenotypically. In conclusion, two novel species of the genus Lactococcus are proposed, namely Lactococcus insecticola Hs20B0-1T (=JCM 33485T=DSM 110147T) and Lactococcus hodotermopsidis Hs30E4-3T (=JCM 33486T=DSM 110148T), respectively.

Amedibacterium intestinale gen. nov., sp. nov., isolated from human faeces, and reclassification of Eubacterium dolichum Moore et al. 1976 (Approved Lists 1980) as Amedibacillus dolichus gen. nov., comb. nov.

Four strains (9CBEGH2T, 9BBH35, 6BBH38 and 6EGH11) of Gram-stain-positive, obligately anaerobic, rod-shaped bacteria were isolated from faecal samples from healthy Japanese humans. The results of 16S rRNA gene sequence analysis indicated that the four strains represented members of the family Erysipelotrichaceae and formed a monophyletic cluster with 'Absiella argi' strain N6H1-5 (99.4% sequence similarity) and Eubacterium sp. Marseille-P5640 (99.3 %). Eubacterium dolichum JCM 10413T (94.2 %) and Eubacterium tortuosum ATCC 25548T (93.7 %) were located near this monophyletic cluster. The isolates, 9CBEGH2T, 'A. argi' JCM 30884 and Eubacterium sp. Marseille-P5640 shared 98.7-99.1% average nucleotide identity (ANI) with each other. Moreover, the in silico DNA-DNA hybridization (DDH) values among three strains were 88.4-90.6%, indicating that these strains represent the same species. Strain 9CBEGH2T showed 21.5-24.1 % in silico DDH values with other related taxa. In addition, the ANI values between strain 9CBEGH2T and other related taxa ranged from 71.2 % to 73.5 %, indicating that this strain should be considered as representing a novel species on the basis of whole-genome relatedness. Therefore, we formally propose a novel name for 'A. argi' strains identified because the name 'A. argi' has been effectively, but not validly, published since 2017. On the basis of the collected data, strain 9CBEGH2T represents a novel species of a novel genus, for which the name Amedibacterium intestinale gen. nov., sp. nov. is proposed. The type strain of A. intestinale is 9CBEGH2T (=JCM 33778T=DSM 110575T).

Alistipes communis sp. nov., Alistipes dispar sp. nov. and Alistipes onderdonkii subsp. vulgaris subsp. nov., isolated from human faeces, and creation of Alistipes onderdonkii subsp. onderdonkii subsp. nov.

Three groups of Gram-stain-negative, obligately anaerobic, rod or coccoid-shaped bacteria, which were phylogenetically assigned in the genus Alistipes belonging to the family Rikenellaceae in the phylum Bacteroidetes, were isolated from the faecal samples of healthy Japanese humans. Group I (strains 5CBH24T and 6CPBBH3) showed highest 16S rRNA gene sequence similarity to 'Alistipes obesi' ph8T (99.73 %). Group II (strain 5CPEGH6T) was related to Alistipes shahii WAL 8301T (96.82 %). Ten strains of group III (3BBH6T, 5CPYCFAH4, 5NYCFAH2 and others) were related to Alistipes onderdonkii DSM 19147T (98.96 %). Group I could be differentiated from other strains by the ability to hydrolyse aesculin and the lack of catalase activity. Strain 5CPEGH6T could be differentiated from A. shahii JCM 16773T by the inability to hydrolyse aesculin and the lack of catalase activity, and so on. Phenotypic characteristics of group III were similar to those of A. onderdonkii JCM 16771T. Strains 5CBH24T, 6CPBBH3 and 'A. obesi' ph8T shared 98.8-98.9 % average nucleotide identity (ANI) with each other. In addition, the in silico DNA-DNA hybridization (DDH) values among three strains were 86.7-89.4 %. Strain 5CPEGH6T showed relatively low values (≤ 84.4 % for ANI ; ≤26.2 % for DDH) with other strains. Three strains in the group III (3BBH6T, 5CPYCFAH4 and 5NYCFAH2) shared 97.9-99.9% ANI with each other. These three strains showed 96.9-97.3 % ANI with A. onderdonkii DSM 19147T. The DDH values of strains 3BBH6T, 5CPYCFAH4 and 5NYCFAH2 among themselves were 80.5-99.8 %, while those compared to A. onderdonkii DSM 19147T were 71.0-73.4 %. On the basis of the collected data, three novel species, Alistipes communis sp. nov. (5CBH24T=JCM 32850T=DSM 108979T), Alistipes dispar sp. nov. (5CPEGH6T=JCM 32848T=DSM 108978T) and Alistipes onderdonkii subsp. vulgaris subsp. nov. (3BBH6T=JCM 32839T=DSM 108977T), are proposed.

Dialister hominis sp. nov., isolated from human faeces.

An obligately anaerobic, Gram-stain-negative, rod or coccobacilli organism was isolated from a faecal sample of a healthy Japanese woman. In the 16S rRNA gene sequence analysis, strain 5BBH33T showed the highest 16S rRNA gene sequence similarity to Dialister succinatiphilus YIT 11850T (95.9 %), Dialister propionicifaciens ADV 1053.03T (94.3 %), Dialister micraerophilus DSM 19965T (93.1 %), Dialister invisus DSM 15470T (92.5 %) and Dialister pneumosintes ATCC 33048T (91.4 %). The hsp60 gene sequence analysis also revealed strain 5BBH33T had relatively low hsp60 gene sequence similarities (74.4-85.3 %) to other Dialister species. Strain 5BBH33T showed 21.8-23.9 % in silico DNA-DNA hybridization values with other Dialister species. In addition, the average nucleotide identity values between strain 5BBH33T and other Dialister species ranged from 68.7-74.2 %, indicating that this strain should be considered as new species based on whole-genome relatedness. Strain 5BBH33T was asaccharolytic and largely unreactive for commercial kit. However, its growth was enhanced by adding 1 % (w/v) succinate to the medium; strain 5BBH33T was able to decarboxylate succinate to propionate. The strain 5BBH33T genome contained the enzymes involved in succinate utilization. These results improve our understanding of succinate-utilizing bacteria. On the basis of the collected data, strain 5BBH33T represents a novel species in the genus Dialister, for which the name Dialister hominis sp. nov. is proposed. The type strain of D. hominis is 5BBH33T (=JCM 33369T=DSM 109768T).

Draft Genome Sequence of Mesosutterella multiformis JCM 32464T, a Member of the Family Sutterellaceae, Isolated from Human Feces.

Here, we report the draft genome sequence of Mesosutterella multiformis JCM 32464T, a new member of the family Sutterellaceae that was isolated from human feces. The genome assembly comprised 2,621,983 bp, with a G+C content of 56.9%. This genomic analysis will be useful for understanding the metabolic activities of this asaccharolytic bacterium.

Comparative genomics of Parolsenella catena and Libanicoccus massiliensis: Reclassification of Libanicoccus massiliensis as Parolsenella massiliensis comb. nov.

Previous analyses based on 16S rRNA and hsp60 genes indicated that Parolsenella catena and Libanicoccus massiliensis were closely related to each other and formed a monophyletic cluster independent of the related Olsenella species. To clarify the relationship of these two species, we determined the genome sequence of P. catena JCM 31932T and compared it with that already sequenced for L. massiliensis Marseille-P3237T. Phylogenetic trees based on the concatenated 37 single-copy ribosomal proteins or RpoB robustly supported the relationship observed in the previous studies. Digital DNA-DNA hybridization and average nucleotide identity (ANI) values between P. catena JCM 31932T and L. massiliensis Marseille-P3237T were 32.6 and 87.8 %, respectively, indicating that P. catena JCM 31932T and L. massiliensis Marseille-P3237T are independent species. Alignment fraction and ANI values between the two genomes were 0.75 and 88.84 %, respectively, thus indicating that the two species should be classified into the same genus. The number of putative orthologous genes shared between the two genomes was 1321, which was significantly larger than those (482-928) reported between L. massiliensis Marseille-P3237T and other closely related species. In addition, the genome of P. catena JCM 31932T had a high degree of synteny conservation with that of L. massiliensis Marseille-P3237T. On the basis of these findings, we propose that L. massiliensis should be reclassified as Parolsenella massiliensis comb. nov.; the type strain is Marseille-P3237T (=JCM 33000T=CCUG 71182T).

Complete Genome Sequence of Phascolarctobacterium faecium JCM 30894, a Succinate-Utilizing Bacterium Isolated from Human Feces.

Phascolarctobacterium faecium is an anaerobic microbe known as a member of the human gut microbiome. Here, we report the complete genome sequence of Phascolarctobacterium faecium JCM 30894 and the elucidation of the mechanism for utilization of succinate by this bacterium based on the genome analysis.

Draft Genome Sequence of Faecalimonas umbilicata JCM 30896T, an Acetate-Producing Bacterium Isolated from Human Feces.

Here, we report the draft genome sequence of Faecalimonas umbilicata JCM 30896T, an acetate-producing bacterium isolated from human feces. The genomic analysis reveals genes for acetate and vitamin B12 synthesis and will facilitate the study of the role of this strain in the human gut.

Mesosutterella multiformis gen. nov., sp. nov., a member of the family Sutterellaceae and Sutterella megalosphaeroides sp. nov., isolated from human faeces.

Two novel, obligately anaerobic, Gram-stain-negative, rod or coccoid-shaped bacteria, designated strains 4NBBH2T and 6FBBBH3T, were isolated from faecal samples of a healthy Japanese woman and man. The 16S rRNA gene sequence analysis showed that these strains represent a distinct lineage within the family Sutterellaceae. Strain 4NBBH2T formed a monophyletic branch between the genera Parasutterella and Sutterella, with sequence similarity to Sutterella stercoricanis CCUG 47620T (92.6 %), followed by Sutterella wadsworthensis WAL 7877 (92.4 %), Sutterella parvirubra YIT 11816T (92.1 %) and Parasutterella secunda YIT 12071T (91.8 %). Strain 6FBBBH3T was affiliated to the genus Sutterella, with highest similarity to S. stercoricanis CCUG 47620T (97.1 %), followed by S. parvirubra YIT 11816T (96.6 %) and S. wadsworthensis WAL 7877 (95.2 %). Strains 4NBBH2T and 6FBBBH3T were asaccharolytic. Analysis of fatty acids revealed that strain 4NBBH2T could be differentiated from Sutterella species (including strain 6FBBBH3T) by the presence of a low concentration of C16 : 1ω7c. The major respiratory quinones of strain 4NBBH2T were menaquinone (MK)-6 and methylmenaquinone (MMK)-6, whereas those of strain 6FBBBH3T were MK-5 and MMK-5. The G+C content of the genomic DNA of strains 4NBBH2T and 6FBBBH3T were 56.9 and 62.8 mol%, respectively. On the basis of the collected data, strain 4NBBH2T represents a novel species in a novel genus of the family Sutterellaceae, for which the name Mesosutterella multiformis gen. nov., sp. nov. is proposed. The type strain is 4NBBH2T (=JCM 32464T=DSM 106860T). We also propose a novel Sutterella species, Sutterellamegalosphaeroides sp. nov., for strain 6FBBBH3T (=JCM 32470T=DSM 106861T).

Draft Genome Sequence of Lawsonibacter asaccharolyticus JCM 32166T, a Butyrate-Producing Bacterium, Isolated from Human Feces.

Here, we report the draft genome sequence of Lawsonibacter asaccharolyticus JCM 32166T, a butyrate-producing bacterium, isolated from human feces. The genomic analysis reveals genes for butyrate synthesis and will facilitate the study on the role of this strain in the human gut.