Non-contiguous finished genome sequence and description of Megasphaera massiliensis sp. nov

The correlation between gut and intra-tumor microbiota and PDAC: Etiology, diagnostics and therapeutics

Pancreatic ductal adenocarcinoma (PDAC) is one of the lethal cancers in the world and its 5-year survival rate is <10%. Due to the unique TME and dense tissue structure, its curative efficacy is far from satisfactory，the immunotherapy is even more invalid. According to the recent studies, the gut and tumor microbiota have been proved to play a key role in the development, progression and prognosis of PDAC. Based on the differences of microbiome composition observed in PDAC patients and normal pancreas, many researches have been made focusing on the latent communication between gut and intra-tumor microbiota and PDAC. In this review, we will demonstrate the potential mechanism of the oncogenic effects of GM and IM and their crucial effects on modulating the TME. Besides, we focus on their interaction with chemotherapeutic and immunotherapeutic drugs and inducing the drug resistance, thus enlightening the promising role to be used to monitor the occurrence of PDAC, accurately modulate the immune environment to promote the therapeutic efficacy and predict the prognosis.

Unique roles of vaginal Megasphaera phylotypes in reproductive health

The composition of the human vaginal microbiome has been extensively studied and is known to influence reproductive health. However, the functional roles of individual taxa and their contributions to negative health outcomes have yet to be well characterized. Here, we examine two vaginal bacterial taxa grouped within the genus Megasphaera that have been previously associated with bacterial vaginosis (BV) and pregnancy complications. Phylogenetic analyses support the classification of these taxa as two distinct species. These two phylotypes, Megasphaera phylotype 1 (MP1) and Megasphaera phylotype 2 (MP2), differ in genomic structure and metabolic potential, suggestive of differential roles within the vaginal environment. Further, these vaginal taxa show evidence of genome reduction and changes in DNA base composition, which may be common features of host dependence and/or adaptation to the vaginal environment. In a cohort of 3870 women, we observed that MP1 has a stronger positive association with bacterial vaginosis whereas MP2 was positively associated with trichomoniasis. MP1, in contrast to MP2 and other common BV-associated organisms, was not significantly excluded in pregnancy. In a cohort of 52 pregnant women, MP1 was both present and transcriptionally active in 75.4 % of vaginal samples. Conversely, MP2 was largely absent in the pregnant cohort. This study provides insight into the evolutionary history, genomic potential and predicted functional role of two clinically relevant vaginal microbial taxa.

Microbial short-chain fatty acids modulate CD8+ T cell responses and improve adoptive immunotherapy for cancer

Emerging data demonstrate that the activity of immune cells can be modulated by microbial molecules. Here, we show that the short-chain fatty acids (SCFAs) pentanoate and butyrate enhance the anti-tumor activity of cytotoxic T lymphocytes (CTLs) and chimeric antigen receptor (CAR) T cells through metabolic and epigenetic reprograming. We show that in vitro treatment of CTLs and CAR T cells with pentanoate and butyrate increases the function of mTOR as a central cellular metabolic sensor, and inhibits class I histone deacetylase activity. This reprogramming results in elevated production of effector molecules such as CD25, IFN-γ and TNF-α, and significantly enhances the anti-tumor activity of antigen-specific CTLs and ROR1-targeting CAR T cells in syngeneic murine melanoma and pancreatic cancer models. Our data shed light onto microbial molecules that may be used for enhancing cellular anti-tumor immunity. Collectively, we identify pentanoate and butyrate as two SCFAs with therapeutic utility in the context of cellular cancer immunotherapy.

The activity of immune cells can be regulated by the microbiome. Here, the authors show that the fatty acids pentanoate and butyrate—normally released by the microbiome—increase the anti-tumour activity of cytotoxic T lymphocytes and chimeric antigen receptor T cells through metabolic and epigenetic reprogramming.

Megasphaera lornae sp. nov., Megasphaera hutchinsoni sp. nov., and Megasphaera vaginalis sp. nov.: novel bacteria isolated from the female genital tract

Six strictly anaerobic Gram-negative bacteria representing three novel species were isolated from the female reproductive tract. The proposed type strains for each species were designated UPII 199-6^T, KA00182^T and BV3C16-1^T. Phylogenetic analyses based on 16S rRNA gene sequencing indicated that the bacterial isolates were members of the genus Megasphaera. UPII 199-6^T and KA00182^T had 16S rRNA gene sequence identities of 99.9 % with 16S rRNA clone sequences previously amplified from the human vagina designated as Megasphaera type 1 and Megasphaera type 2, members of the human vaginal microbiota associated with bacterial vaginosis, preterm birth and HIV acquisition. UPII 199-6^T exhibited sequence identities ranging from 92.9 to 93.6 % with validly named Megasphaera isolates and KA00182^T had 16S rRNA gene sequence identities ranging from 92.6-94.2 %. BV3C16-1^T was most closely related to Megasphaera cerevisiae with a 16S rRNA gene sequence identity of 95.4 %. Cells were coccoid or diplococcoid, non-motile and did not form spores. Genital tract isolates metabolized organic acids but were asaccharolytic. The isolates also metabolized amino acids. The DNA G+C content for the genome sequences of UPII 199-6^T, KA00182^T and BV3C16-1^T were 46.4, 38.9 and 49.8 mol%, respectively. Digital DNA-DNA hybridization and average nucleotide identity between the genital tract isolates and other validly named Megasphaera species suggest that each isolate type represents a new species. The major fatty acid methyl esters include the following: C_12 : 0, C_16 : 0, C_16 : 0 dimethyl acetal (DMA) and summed feature 5 (C_15 : 0 DMA and/or C_14 : 0 3-OH) in UPII 199-6^T; C_16 : 0 and C_16 : 1 cis 9 in KA00182^T; C_12 : 0; C_14 : 0 3-OH; and summed feature 5 in BV3C16-1^T. The isolates produced butyrate, isobutyrate, and isovalerate but there were specific differences including production of formate and propionate. Together, these data indicate that UPII 199-6^T, KA00182^T and BV3C16-1^T represent novel species within the genus Megasphaera. We propose the following names: Megasphaera lornae sp. nov. for UPII 199-6^T representing the type strain of this species (=DSM 111201^T=ATCC TSD-205^T), Megasphaera hutchinsoni sp. nov. for KA00182^T representing the type strain of this species (=DSM 111202^T=ATCC TSD-206^T) and Megasphaera vaginalis sp. nov. for BV3C16-1^T representing the type strain of this species (=DSM 111203^T=ATCC TSD-207^T).

Megasphaera vaginalis sp. nov. and Anaerococcus vaginimassiliensis sp. nov., new bacteria isolated from vagina of French woman with bacterial vaginosis

Using the culturomics method, two strains were isolated, identified and characterized following the taxonogenomics concept. Megasphaera vaginalis sp. nov. strain Marseille-P4512 (= CSURP4512) and Anaerococcus vaginimassiliensis sp. nov. strain Marseille-P4857 (= CSURP4857) were isolated from the vagina of a French woman. The phylogenic tree, phenotypic criteria and genomic analysis described here clearly show that these two bacteria are different from previously known bacterial species with standing in nomenclature and new members of Firmicutes phylum.

Colibacter massiliensis gen. nov. sp. nov., a novel Gram-stain-positive anaerobic diplococcal bacterium, isolated from the human left colon

The gut microbiota is considered to play a key role in human health. As a consequence, deciphering its microbial diversity is mandatory. A polyphasic taxonogenomic strategy based on the combination of phenotypic and genomic analyses was used to characterize a new bacterium, strain Marseille-P2911. This strain was isolated from a left colon sample of a 60-year old man who underwent a colonoscopy for an etiological investigation of iron-deficiency anemia in Marseille, France. On the basis of 16S rRNA sequence comparison, the closest phylogenetic neighbor was Anaeroglobus geminatus (94.59% 16S rRNA gene sequence similarity) within the family Veillonellaceae. Cells were anaerobic, Gram-stain-positive, non-spore-forming, catalase/oxidase negative cocci grouped in pairs. The bacterium was able to grow at 37 °C after 2 days of incubation. Strain Marseille-P2911 exhibited a genome size of 1,715,864-bp with a 50.2% G + C content, and digital DNA-DNA hybridization (dDDH) and OrthoANI values with A. geminatus of only 19.1 ± 4.5% and 74.42%, respectively. The latter value being lower than the threshold for genus delineation (80.5%), we propose the creation of the new genus Colibacter gen. nov., with strain Marseille-P2911^T (=DSM 103304 = CSUR P2911) being the type strain of the new species Colibacter massiliensis gen. nov., sp. nov.

In vitro Characterization of Gut Microbiota-Derived Bacterial Strains With Neuroprotective Properties

Neurodegenerative diseases are disabling, incurable, and progressive conditions characterized by neuronal loss and decreased cognitive function. Changes in gut microbiome composition have been linked to a number of neurodegenerative diseases, indicating a role for the gut-brain axis. Here, we show how specific gut-derived bacterial strains can modulate neuroinflammatory and neurodegenerative processes in vitro through the production of specific metabolites and discuss the potential therapeutic implications for neurodegenerative disorders. A panel of fifty gut bacterial strains was screened for their ability to reduce pro-inflammatory IL-6 secretion in U373 glioblastoma astrocytoma cells. Parabacteroides distasonis MRx0005 and Megasphaera massiliensis MRx0029 had the strongest capacity to reduce IL-6 secretion in vitro. Oxidative stress plays a crucial role in neuroinflammation and neurodegeneration, and both bacterial strains displayed intrinsic antioxidant capacity. While MRx0005 showed a general antioxidant activity on different brain cell lines, MRx0029 only protected differentiated SH-SY5Y neuroblastoma cells from chemically induced oxidative stress. MRx0029 also induced a mature phenotype in undifferentiated neuroblastoma cells through upregulation of microtubule-associated protein 2. Interestingly, short-chain fatty acid analysis revealed that MRx0005 mainly produced C1-C3 fatty acids, while MRx0029 produced C4-C6 fatty acids, specifically butyric, valeric and hexanoic acid. None of the short-chain fatty acids tested protected neuroblastoma cells from chemically induced oxidative stress. However, butyrate was able to reduce neuroinflammation in vitro, and the combination of butyrate and valerate induced neuronal maturation, albeit not to the same degree as the complex cell-free supernatant of MRx0029. This observation was confirmed by solvent extraction of cell-free supernatants, where only MRx0029 methanolic fractions containing butyrate and valerate showed an anti-inflammatory activity in U373 cells and retained the ability to differentiate neuroblastoma cells. In summary, our results suggest that the pleiotropic nature of live biotherapeutics, as opposed to isolated metabolites, could be a promising novel drug class in drug discovery for neurodegenerative disorders.

An Update on the Novel Genera and Species and Revised Taxonomic Status of Bacterial Organisms Described in 2016 and 2017

Recognition and acknowledgment of novel bacterial taxonomy and nomenclature revisions can impact clinical practice, disease epidemiology, and routine clinical microbiology laboratory operations. The Journal of Clinical Microbiology (JCM) herein presents its biannual report summarizing such changes published in the years 2016 and 2017, as published and added by the International Journal of Systematic and Evolutionary Microbiology Noteworthy discussion centers around descriptions of novel Corynebacteriaceae and an anaerobic mycolic acid-producing bacterium in the suborder Corynebacterineae; revisions within the Propionibacterium, Clostridium, Borrelia, and Enterobacter genera; and a major reorganization of the family Enterobacteriaceae. JCM intends to sustain this series of reports as advancements in molecular genetics, whole-genome sequencing, and studies of the human microbiome continue to produce novel taxa and clearer understandings of bacterial relatedness.

Megasphaera stantonii sp. nov., a butyrate-producing bacterium isolated from the cecum of a healthy chicken

A novel mesophilic, anaerobic, Gram-stain-negative bacterium was isolated from the cecum of a healthy white leghorn chicken, and designated AJH120^T. Cells were coccoid or diplococcoid with an average size of 0.8-1.8 µm and were non-motile with no evidence of spores. Phylogenetic analysis of 16S rRNA gene sequences revealed this organism to be a member of the genus Megasphaera, with the closest relatives being Megasphaera elsdenii (95 % sequence identity) and Megasphaera cerevisiae (95 % sequence identity). Growth was observed between 30 and 50 °C and between pH 5.0 and 9.0. AJH120^T utilized a variety of carbon sources, including succinate, gluconate, fructose, ribose and pyruvate, as well as many individual amino acids. The DNA G+C content for the genome sequence of AJH120^T was 52.1 mol%. Digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI) and average amino acid identity (AAI) between AJH120^T and close taxonomic relatives, indicated divergence consistent with the strain representing a novel species. The major fatty acid methyl esters of the organism were C12 : 0, C14 : 0 3-OH, C18 : 1ω9c, C16 : 0 and C16 : 1ω9c. AJH120^T was able to produce several short chain fatty acids, including butyrate, acetate, propionate and isovalerate. Together, these data indicate that AJH120^T represents a novel species within the genus Megasphaera. We propose the name Megasphaerastantonii sp. nov. for the species. The type strain of this species is AJH120^T (=DSM 106750^T=CCUG 71842^T).

Megasphaera hexanoica sp. nov., a medium-chain carboxylic acid-producing bacterium isolated from a cow rumen

Strain MHT, a strictly anaerobic, Gram-stain-negative, non-spore-forming, spherical coccus or coccoid-shaped microorganism, was isolated from a cow rumen during a screen for hexanoic acid-producing bacteria. The microorganism grew at 30-40 °C and pH 5.5-7.5 and exhibited production of various short- and medium-chain carboxylic acids (acetic acid, butyric acid, pentanoic acid, isobutyric acid, isovaleric acid, hexanoic acid, heptanoic acid and octanoic acid), as well as H2 and CO2 as biogas. Phylogenetic analysis based on 16S rRNA gene sequencing demonstrated that MHT represents a member of the genus Megasphaera, with the closest relatives being Megapsphaera indica NMBHI-10T (94.1 % 16S rRNA sequence similarity), Megasphaera elsdenii DSM 20460T (93.8 %) and Megasphaera paucivorans DSM 16981T (93.8 %). The major cellular fatty acids produced by MHT included C12 : 0, C16 : 0, C18 : 1cis 9, and C18 : 0, and the DNA G+C content of the MHT genome is 51.8 mol%. Together, the distinctive phenotypic and phylogenetic characteristics of MHT indicate that this microorganism represents a novel species of the genus Megasphaera, for which the name Megasphaera hexanoica sp. nov. is herein proposed. The type strain of this species is MHT (=KCCM 43214T=JCM 31403T).

Biochemical and genome sequence analyses of Megasphaera sp. strain DISK18 from dental plaque of a healthy individual reveals commensal lifestyle

Much of the work in periodontal microbiology in recent years has focused on identifying and understanding periodontal pathogens. As the majority of oral microbes have not yet been isolated in pure form, it is essential to understand the phenotypic characteristics of microbes to decipher their role in oral environment. In this study, strain DISK18 was isolated from gingival sulcus and identified as a Megasphaera species. Although metagenomics studies revealed Megasphaera species as a major group within the oral habitat, they have never been isolated in cultivable form to date. Therefore, we have characterized the DISK18 strain to better understand its role in the periodontal ecosystem. Strain Megasphaera sp. DISK18 displayed the ability to adhere and self-aggregate, which are essential requisite features for inhabiting and persisting in oral cavity. It also coaggregated with other pioneer oral colonizers like Streptococcus and Lactobacillus species but not with Veillonella. This behaviour points towards its role in the ecologic succession of a multispecies biofilm as an early colonizer. The absence of virulence determining genes as observed in whole genome sequence analysis coupled with an inability to degrade collagen reveals that Megasphaera sp. strain DISK18 is likely not a pathogenic species and emphasizes its commensal lifestyle.

The rebirth of culture in microbiology through the example of culturomics to study human gut microbiota

Bacterial culture was the first method used to describe the human microbiota, but this method is considered outdated by many researchers. Metagenomics studies have since been applied to clinical microbiology; however, a "dark matter" of prokaryotes, which corresponds to a hole in our knowledge and includes minority bacterial populations, is not elucidated by these studies. By replicating the natural environment, environmental microbiologists were the first to reduce the "great plate count anomaly," which corresponds to the difference between microscopic and culture counts. The revolution in bacterial identification also allowed rapid progress. 16S rRNA bacterial identification allowed the accurate identification of new species. Mass spectrometry allowed the high-throughput identification of rare species and the detection of new species. By using these methods and by increasing the number of culture conditions, culturomics allowed the extension of the known human gut repertoire to levels equivalent to those of pyrosequencing. Finally, taxonogenomics strategies became an emerging method for describing new species, associating the genome sequence of the bacteria systematically. We provide a comprehensive review on these topics, demonstrating that both empirical and hypothesis-driven approaches will enable a rapid increase in the identification of the human prokaryote repertoire.

Non-contiguous finished genome sequence and description of Clostridium saudii sp. nov

Clostridium saudii strain JCC(T) sp. nov. is the type strain of C. saudii sp. nov., a new species within the genus Clostridia. This strain, whose genome is described here, was isolated from a fecal sample collected from an obese 24-year-old (body mass index 52 kg/m2) man living in Jeddah, Saudi Arabia. C. saudii is a Gram-positive, anaerobic bacillus. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,653,762 bp long genome contains 3,452 protein-coding and 53 RNA genes, including 4 rRNA genes.

Non-contiguous finished genome sequence and description of Collinsella massiliensis sp. nov

Collinsella massiliensis strain GD3(T) is the type strain of Collinsella massiliensis sp. nov., a new species within the genus Collinsella. This strain, whose genome is described here, was isolated from the fecal flora of a 53-year-old French Caucasoid woman who had been admitted to intensive care unit for Guillain-Barré syndrome. Collinsella massiliensis is a Gram-positive, obligate anaerobic, non motile and non sporulating bacillus. Here, we describe the features of this organism, together with the complete genome sequence and annotation. The genome is 2,319,586 bp long (1 chromosome, no plasmid), exhibits a G+C content of 65.8% and contains 2,003 protein-coding and 54 RNA genes, including 1 rRNA operon.

Non contiguous-finished genome sequence and description of Clostridium jeddahense sp. nov

Clostridium jeddahense strain JCD(T) (= CSUR P693 = DSM 27834) is the type strain of C. jeddahense sp. nov. This strain, whose genome is described here, was isolated from the fecal flora of an obese 24 year-old Saudian male (BMI=52 kg/m(2)). Clostridium jeddahense strain JCD(T) is an obligate Gram-positive bacillus. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,613,503 bp long genome (1 chromosome, no plasmid) exhibits a G+C content of 51.95% and contains 3,462 protein-coding and 53 RNA genes, including 4 rRNA genes.

Non-contiguous finished genome sequence and description of Corynebacterium jeddahense sp. nov

Corynebacterium jeddahense sp. nov., strain JCB^T, is the type strain of Corynebacterium jeddahense sp. nov., a new species within the genus Corynebacterium. This strain, whose genome is described here, was isolated from fecal flora of a 24-year-old Saudi male suffering from morbid obesity. Corynebacterium jeddahense is a Gram-positive, facultative anaerobic, nonsporulating bacillus. Here, we describe the features of this bacterium, together with the complete genome sequencing and annotation, and compare it to other member of the genus Corynebacterium. The 2,472,125 bp-long genome (1 chromosome but not plasmid) contains 2,359 protein-coding and 53 RNA genes, including 1 rRNA operon.

Genome sequence and description of Nesterenkonia massiliensis sp. nov. strain NP1(T.)

Nesterenkonia massiliensis sp. nov., strain NP1^T, is the type strain of Nesterenkonia massiliensis sp. nov., a new species within the genus Nesterenkonia. This strain, whose genome is described here, was isolated from the feces of a 32-year-old French woman suffering from AIDS and living in Marseille. Nesterenkonia massiliensis is a Gram-positive aerobic coccus. Here, we describe the features of this bacterium, together with the complete genome sequencing and annotation. The 2,726,371 bp long genome (one chromosome but no plasmid) contains 2,663 protein-coding and 51 RNA genes, including 1 rRNA operon.

Genome sequence and description of Bacteroides timonensis sp. nov

Bacteroides timonensis strain AP1^T (= CSUR P194 = DSM 26083) is the type strain of B. timonensis sp. nov. This strain, whose genome is described here, was isolated from the fecal flora of a 21-year-old French Caucasoid female who suffered from severe anorexia nervosa. Bacteroides timonensis is a Gram-negative, obligate anaerobic bacillus. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 7,130,768 bp long genome (1 chromosome, no plasmid) exhibits a G+C content of 43.3% and contains 5,786 protein-coding and 59 RNA genes, including 2 rRNA genes.

Non contiguous-finished genome sequence and description of Enorma timonensis sp. nov

Enorma timonensis strain GD5(T) sp. nov., is the type strain of E. timonensis sp. nov., a new member of the genus Enorma within the family Coriobacteriaceae. This strain, whose genome is described here, was isolated from the fecal flora of a 53-year-old woman hospitalized for 3 months in an intensive care unit. E. timonensis is an obligate anaerobic rod. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 2,365,123 bp long genome (1 chromosome but no plasmid) contains 2,060 protein-coding and 52 RNA genes, including 4 rRNA genes.

Comparative genome analysis of Megasphaera sp. reveals niche specialization and its potential role in the human gut

With increasing number of novel bacteria being isolated from the human gut ecosystem, there is a greater need to study their role in the gut ecosystem and their effect on the host health. In the present study, we carried out in silico genome-wide analysis of two novel Megasphaera sp. isolates NM10 (DSM25563) and BL7 (DSM25562), isolated from feces of two healthy individuals and validated the key features by in vitro studies. The analysis revealed the general metabolic potential, adaptive features and the potential effects of these isolates on the host. The comparative genome analysis of the two human gut isolates NM10 and BL7 with ruminal isolate Megasphaera elsdenii (DSM20460) highlighted the differential adaptive features for their survival in human gut. The key findings include features like bile resistance, presence of various sensory and regulatory systems, stress response systems, membrane transporters and resistance to antibiotics. Comparison of the “glycobiome” based on the genomes of the ruminal isolate with the human gut isolates NM10 and BL revealed the presence of diverse and unique sets of Carbohydrate-Active enzymes (CAZymes) amongst these isolates, with a higher collection of CAZymes in the human gut isolates. This could be attributed to the difference in host diet and thereby the environment, consequently suggesting host specific adaptation in these isolates. In silico analysis of metabolic potential predicted the ability of these isolates to produce important metabolites like short chain fatty acids (butyrate, acetate, formate, and caproate), vitamins and essential amino acids, which was further validated by in vitro experiments. The ability of these isolates to produce important metabolites advocates for a potential healthy influence on the host. Further in vivo studies including transcriptomic and proteomic analysis will be required for better understanding the role and impact of these Megasphaera sp. isolates NM10 and BL7 on the human host.