Gut microbiome in association with chemotherapy-induced toxicities among patients with breast cancer.

BACKGROUND: Little research has focused on the relationship between gut microbiome and chemotherapy-induced toxicity. METHODS: This prospective study involves 301 patients with breast cancer who had prechemotherapy stool samples collected. Gut microbiome was sequenced by shotgun metagenomics; associations with chemotherapy-induced toxicities during first-line treatment by gut microbial diversity, composition, and metabolic pathways with severe (i.e., grade ≥3) hematological and gastrointestinal toxicities were evaluated via multivariable logistic regression. RESULTS: High prechemotherapy α-diversity was associated with a significantly reduced risk of both severe hematological toxicity (odds ratio [OR] = 0.94; 95% CI, 0.89-0.99; p = .048) and neutropenia (OR = 0.94; 95% CI, 0.89-0.99; p = .016). A high abundance of phylum Synergistota, class Synergistia, and order Synergistales were significantly associated with a reduced risk of severe neutropenia; conversely, enrichment of phylum Firmicutes C, class Negativicutes, phylum Firmicutes I, and class Bacilli A, order Paenibacillales were significantly associated with an increased risk of severe neutropenia (p range: 0.012-2.32 × 10-3; false discovery rate <0.1). Significant positive associations were also observed between severe nausea/vomiting and high Chao1 indexes, ß-diversity (p < .05), 20 species belonging to the family Lachnospiraceae, Oscillospiraceae, and Ruminococcaceae (p value range: 6.14 × 10-3 to 1.33 × 10-5; false discovery rate <0.1), and three metabolic pathways involved in reductive tricarboxylic acid cycle I and cycle II, and an incomplete reductive tricarboxylic acid cycle (p < .01). Conversely, a high abundance of species Odoribacter laneus and the pathway related to the L-proline biosynthesis II were inversely associated with severe nausea/vomiting. CONCLUSIONS: Our study suggests that gut microbiota may be a potential preventive target to reduce chemotherapy-induced toxicity.

Metagenomic gut microbiome analysis of Japanese patients with multiple chemical sensitivity/idiopathic environmental intolerance.

BACKGROUND: Although the pathology of multiple chemical sensitivity (MCS) is unknown, the central nervous system is reportedly involved. The gut microbiota is important in modifying central nervous system diseases. However, the relationship　between the gut microbiota and MCS remains unclear. This study aimed to identify gut microbiota variations associated with MCS using shotgun metagenomic sequencing of fecal samples. METHODS: We prospectively recruited 30 consecutive Japanese female patients with MCS and analyzed their gut microbiomes using shotgun metagenomic sequencing. The data were compared with metagenomic data obtained from 24 age- and sex-matched Japanese healthy controls (HC). RESULTS: We observed no significant difference in alpha and beta diversity of the gut microbiota between the MCS patients and HC. Focusing on the important changes in the literatures, at the genus level, Streptococcus, Veillonella, and Akkermansia were significantly more abundant in MCS patients than in HC (p < 0.01, p < 0.01, p = 0.01, respectively, fold change = 4.03, 1.53, 2.86, respectively). At the species level, Akkermansia muciniphila was significantly more abundant (p = 0.02, fold change = 3.3) and Faecalibacterium prausnitzii significantly less abundant in MCS patients than in HC (p = 0.03, fold change = 0.53). Functional analysis revealed that xylene and dioxin degradation pathways were significantly enriched (p < 0.01, p = 0.01, respectively, fold change = 1.54, 1.46, respectively), whereas pathways involved in amino acid metabolism and synthesis were significantly depleted in MCS (p < 0.01, fold change = 0.96). Pathways related to antimicrobial resistance, including the two-component system and cationic antimicrobial peptide resistance, were also significantly enriched in MCS (p < 0.01, p < 0.01, respectively, fold change = 1.1, 1.2, respectively). CONCLUSIONS: The gut microbiota of patients with MCS shows dysbiosis and alterations in bacterial functions related to exogenous chemicals and amino acid metabolism and synthesis. These findings may contribute to the further development of treatment for MCS. TRIAL REGISTRATION: This study was registered with the University Hospital Medical Information Clinical Trials Registry as UMIN000031031. The date of first trial registration: 28/01/2018.

Microbial carbohydrate active enzyme (CAZyme) genes and diversity from Menagesha Suba natural forest soils of Ethiopia as revealed by shotgun metagenomic sequencing.

BACKGROUND: The global over-reliance on non-renewable fossil fuels has led to the emission of greenhouse gases, creating a critical global environmental challenge. There is an urgent need for alternative solutions like biofuels. Advanced biofuel is a renewable sustainable energy generated from lignocellulosic plant materials, which can significantly contribute to mitigating CO2 emissions. Microbial Carbohydrate Active Enzymes (CAZymes) are the most crucial enzymes for the generation of sustainable biofuel energy. The present study designed shotgun metagenomics approaches to assemble, predict, and annotate, aiming to gain an insight into the taxonomic diversity, annotate CAZymes, and identify carbohydrate hydrolyzing CAZymes from microbiomes in Menagesha suba forest soil for the first time. RESULTS: The microbial diversity based on small subunit (SSU) rRNA analysis revealed the dominance of the bacterial domain representing 81.82% and 92.31% in the studied samples. Furthermore, the phylum composition result indicated the dominance of the phyla Proteobacteria (23.08%, 27.27%), Actinobacteria (11.36%, 20.51%), and Acidobacteria (10.26%, 15.91%). The study also identified unassigned bacteria which might have a unique potential for biopolymer hydrolysis. The metagenomic study revealed that 100,244 and 65,356 genes were predicted from the two distinct samples. A total number of 1806 CAZyme genes were identified, among annotated CAZymes, 758 had a known enzyme assigned to CAZymes. Glycoside hydrolases (GHs) CAZyme family contained most of the CAZyme genes with known enzymes such as ß-glucosidase, endo-ß-1,4-mannanase, exo-ß-1,4-glucanase, α-L-arabinofuranosidase and oligoxyloglucan reducing end-specific cellobiohydrolase. On the other hand, 1048 of the identified CAZyme genes were putative CAZyme genes with unknown enzymatical activity and the majority of which belong to the GHs family. CONCLUSIONS: In general, the identified putative CAZymes genes open up an opportunity for the discovery of new enzymes responsible for hydrolyzing biopolymers utilized for biofuel energy generation. This finding is used as a first-hand piece of evidence to serve as a benchmark for further and comprehensive studies to unveil novel classes of bio-economically valuable genes and their encoded products.

Treatment response in rheumatoid arthritis is predicted by the microbiome: a large observational study in UK DMARD-naïve patients.

OBJECTIVES: Disease-modifying antirheumatic drugs (DMARDs) are first line treatment in rheumatoid arthritis (RA). Treatment response to DMARDs is patient-specific, dose efficacy is difficult to predict and long-term results variable. The gut microbiota are known to play a pivotal role in prodromal and early-disease RA, manifested by Prevotella spp. enrichment. The clinical response to therapy may be mediated by microbiota, and large-scale studies assessing the microbiome are few. This study assessed whether microbiome signals were associated with, and predictive of, patient response to DMARD-treatment. Accurate early identification of those who will respond poorly to DMARD therapy would allow selection of alternative treatment (e.g. biologic therapy), and potentially improve patient outcome. METHODS: A multicentre, longitudinal, observational study of stool- and saliva microbiome was performed in DMARD-naïve, newly diagnosed RA patients during introduction of DMARD treatment. Clinical data and samples were collected at baseline (n = 144) in DMARD-naïve patients and at six weeks (n = 117) and 12 weeks (n = 95) into DMARD-therapy. Samples collected (n = 365 stool, n = 365 saliva) underwent shotgun sequencing. Disease activity measures were collected at each timepoint and minimal clinically important improvement determined. RESULTS: In total, 26 stool microbes were found to decrease in those manifesting a minimal clinically important improvement. Prevotella spp. and Streptococcus spp. were the predominant taxa to decline following six weeks and 12 weeks of DMARDs, respectively. Furthermore, baseline microbiota of DMARD-naïve patients were indicative of future response. CONCLUSION: DMARDs appear to restore a perturbed microbiome to a eubiotic state. Moreover, microbiome status can be used to predict likelihood of patient response to DMARD.

One Health Threat of Treated Wastewater Discharge in Urban Ohio Rivers: Implications for Surface Water and Fish Gut Microbiome and Resistome.

Wastewater treatment plants (WWTPs) are thought to be a major disseminating source of antibiotic resistance (AR) to the environment, establishing a crucial connection between human and environmental resistome. The objectives of this study were to determine how wastewater effluents impact microbiome and resistome of freshwater and fish, and identify potential AR-carrying clinically relevant pathogens in these matrices. We analyzed wastewater influent and effluent from four WWTPs in three metropolitan areas of Ohio, USA via shotgun metagenomic sequencing. We also sequenced river water and fish guts from three reaches (upstream, at the WWTP outfall, and downstream). Notably, we observed a decline in microbiome diversity and AR gene abundance from wastewater to the receiving river. We also found significant differences by reach and trophic level (diet) in beta-diversity of the fish gut microbiomes. SourceTracker revealed that 0.443 and 0.248 more of the of the fish gut microbiome was sourced from wastewater effluent in fish from the outfall and downstream locations, respectively, compared to upstream fish. Additionally, AR bacteria of public health concern were annotated in effluent and river water samples, indicating potential concern for human exposure. In summary, our findings show the continued role of wastewater as a significant AR reservoir and underscores the considerable impact of wastewater discharge on aquatic wildlife, which highlights the One Health nature of this issue.

The Microbiomes in Lichen and Moss Biocrust Contribute Differently to Carbon and Nitrogen Cycles in Arid Ecosystems.

Biological soil crusts (biocrusts) are distributed in arid and semiarid regions across the globe. Microorganisms are an essential component in biocrusts. They add and accelerate critical biochemical processes. However, little is known about the functional genes and metabolic processes of microbiomes in lichen and moss biocrust. This study used shotgun metagenomic sequencing to compare the microbiomes of lichen-dominated and moss-dominated biocrust and reveal the microbial genes and metabolic pathways involved in carbon and nitrogen cycling. The results showed that Actinobacteria, Bacteroidetes, and Acidobacteria were more abundant in moss biocrust than lichen biocrust, while Proteobacteria and Cyanobacteria were more abundant in lichen biocrust than moss biocrust. The relative abundance of carbohydrate-active enzymes and enzymes associated with carbon and nitrogen metabolism differed significantly between microbiomes of the two biocrust types. However, in the microbial communities of both biocrust types, respiration pathways dominated over carbon fixation pathways. The genes encoding carbon monoxide dehydrogenase were more abundant than those encoding ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCo) involved in carbon fixation. Similarly, metabolic N-pathway diversity was dominated by nitrogen reduction, followed by denitrification, with nitrogen fixation the lowest proportion. Gene diversity involved in N cycling differed between the microbiomes of the two biocrust types. Assimilatory nitrate reduction genes had higher relative abundance in lichen biocrust, whereas dissimilatory nitrate reduction genes had higher relative abundance in moss biocrust. As dissolved organic carbon and soil organic carbon are considered the main drivers of the community structure in the microbiome of biocrust, these results indicate that biocrust type has a pivotal role in microbial diversity and related biogeochemical cycling.

Associations between the postpartum uterine and vaginal microbiota and the subsequent development of purulent vaginal discharge vary with dairy cow breed and parity.

The objective of this study was to characterize the species composition and functional potential of the vaginal and uterine microbiota at 1 wk postpartum in dairy cows diagnosed with or without purulent vaginal discharge (PVD) at 3 wk postpartum. The hypothesis was that differences in the vaginal and uterine microbiota between cows diagnosed with (PVD+) or without (PVD-) PVD were dependent on parity and breed. Cytobrush samples of the vagina and uterus were collected at 1 wk postpartum from 36 Holstein-Friesian (7 primiparous and 29 multiparous) and 29 Jersey (10 primiparous and 19 multiparous) cows. Microbial DNA was isolated from each sample and processed for shotgun metagenomic sequencing. The odds of multiparous cows being diagnosed as PVD+ was less compared with primiparous cows (OR = 0.21). Neither the α-diversity nor ß-diversity of the uterine and vaginal microbiota were associated with PVD but the ß-diversity was different between breeds and between parities. In the vagina of primiparous cows, differences in the microbiota of PVD- and PVD+ cows were minor, but the microbiota of multiparous PVD+ cows had greater relative abundance of Fusobacterium necrophorum, Trueperella pyogenes, Porphyromonas levii, and greater functional potential for amino acid and protein synthesis, energy metabolism, and growth compared with PVD- cows. The uterus of primiparous PVD+ cows had lesser relative abundance of Bacteroides heparinolyticus compared with PVD- cows. In the uterine microbiota, differences included greater functional potential for cellulose biosynthesis and fucose catabolism in multiparous PVD+ cows compared with PVD- cows. In the uterine microbiota of primiparous PVD+ cows, the functional potential for gram-negative cell wall synthesis and for negative regulation of tumor necrosis factor signaling was lesser compared with multiparous PVD+ cows. In the vagina of Holstein-Friesian PVD+ cows, the relative abundance of Caviibacter abscessus was greater whereas in the vagina of Jersey PVD+ cows the relative abundance of Catenibacterium mitsuokai, Finegoldia magna, Klebsiella variicola, and Streptococcus anginosus was greater compared with PVD- cows. In the uterine microbiota of Holstein-Friesian cows, the functional potential for spermidine biosynthesis was reduced compared with PVD- cows. In summary, differences in the species composition and functional potential of the vaginal and uterine microbiota between PVD- and PVD+ cows were dependent on parity and breed. The findings suggest that alternative strategies may be required to treat PVD for different parities and breeds of dairy cow.

Effects of tillage patterns and stover mulching on N2O production, nitrogen cycling genes and microbial dynamics in black soil.

Stover-covered no-tillage (NT) is of great significance to the rational utilization of stover resources and improvement of cultivated land quality, and also has a profound impact on ensuring groundwater, food and ecosystem security. However, the effects of tillage patterns and stover mulching on soil nitrogen turnover remain elusive. Based on the long-term conservation tillage field experiment in the mollisol area of Northeast China since 2007, the shotgun metagenomic sequencing of soils and microcosm incubation were combined with physical and chemical analyses, alkyne inhibition analysis to elucidate the regulatory mechanisms of NT and stover mulching on the farmland soil nitrogen emissions and microbial nitrogen cycling genes. Compared with conventional tillage (CT), NT stover mulching significantly reduced the emission of N2O instead of CO2, especially when 33% mulching was adopted, and correspondingly the nitrate nitrogen of NT33 was higher than that of other mulching amounts. The stover mulching was associated with higher total nitrogen, soil organic carbon and pH. The abundance of AOB (ammonia-oxidizing bacteria)-amoA (ammonia monooxygenase subunit A) was substantially increased by stover mulching, while the abundance of denitrification genes was reduced in most cases. Under alkyne inhibition, the tillage mode, treatment time, gas condition and interactions between them noticeably influenced the N2O emission and nitrogen transformation. In CT, NT0 (no mulching) and NT100 (full mulching), the relative contribution of AOB to N2O production was markedly higher than that of ammonia oxidizing archaea. Different tillage modes were associated with distinct microbial community composition, albeit NT100 was closer to CT than to NT0. Compared with CT, the co-occurrence network of microbial communities was more complex in NT0 and NT100. Our findings suggest that maintaining a low-quantity stover mulching could regulate soil nitrogen turnover toward proficiently enhancing soil health and regenerative agriculture, and coping with global climate change.

Prospective study of oral microbiome and gastric cancer risk among Asian, African American and European American populations.

Colonization of specific bacteria in the human mouth was reported to be associated with gastric cancer risk. However, previous studies were limited by retrospective study designs and low taxonomic resolutions. We performed a prospective case-control study nested within three cohorts to investigate the relationship between oral microbiome and gastric cancer risk. Shotgun metagenomic sequencing was employed to characterize the microbiome in prediagnostic buccal samples from 165 cases and 323 matched controls. Associations of overall microbial richness and abundance of microbial taxa, gene families and metabolic pathways with gastric cancer risk were evaluated via conditional logistic regression. Analyses were performed within each cohort, and results were combined by meta-analyses. We found that overall microbial richness was associated with decreased gastric cancer risk, with an odds ratio (OR) per standard deviation (SD) increase in Simpson's reciprocal index of 0.77 (95% confidence interval [CI] = 0.61-0.99). Nine taxa, 38 gene families and six pathways also showed associations with gastric cancer risk at P < .05. Neisseria mucosa and Prevotella pleuritidis were enriched, while Mycoplasma orale and Eubacterium yurii were depleted among cases with ORs and 95% CIs per SD increase in centered log-ratio transformed taxa abundance of 1.31 (1.03-1.67), 1.26 (1.00-1.57), 0.74 (0.59-0.94) and 0.80 (0.65-0.98), respectively. The top two gene families (P = 3.75 × 10-4 and 3.91 × 10-4 ) and pathways (P = 1.75 × 10-3 and 1.53 × 10-3 ) associated with gastric cancer were related to the decreased risk and are involved in hexitol metabolism. Our study supports the hypothesis that oral microbiota may play a role in gastric cancer etiology.

Oral and gastric microbiome in relation to gastric intestinal metaplasia.

Evidence suggests that Helicobacter pylori plays a role in gastric cancer (GC) initiation. However, epidemiologic studies on the specific role of other bacteria in the development of GC are lacking. We conducted a case-control study of 89 cases with gastric intestinal metaplasia (IM) and 89 matched controls who underwent upper gastrointestinal endoscopy at three sites affiliated with NYU Langone Health. We performed shotgun metagenomic sequencing using oral wash samples from 89 case-control pairs and antral mucosal brushing samples from 55 case-control pairs. We examined the associations of relative abundances of bacterial taxa and functional pathways with IM using conditional logistic regression with and without elastic-net penalty. Compared with controls, oral species Peptostreptococcus stomatis, Johnsonella ignava, Neisseria elongata and Neisseria flavescens were enriched in cases (odds ratios [ORs] = 1.29-1.50, P = .004-.01) while Lactobacillus gasseri, Streptococcus mutans, S parasanguinis and S sanguinis were under-represented (ORs = 0.66-0.76, P = .006-.042) in cases. Species J ignava and Filifactor alocis in the gastric microbiota were enriched (ORs = 3.27 and 1.43, P = .005 and .035, respectively), while S mutans, S parasanguinis and S sanguinis were under-represented (ORs = 0.61-0.75, P = .024-.046), in cases compared with controls. The lipopolysaccharide and ubiquinol biosynthesis pathways were more abundant in IM, while the sugar degradation pathways were under-represented in IM. The findings suggest potential roles of certain oral and gastric microbiota, which are correlated with regulation of pathways associated with inflammation, in the development of gastric precancerous lesions.

Yoghurt consumption is associated with changes in the composition of the human gut microbiome and metabolome.

BACKGROUND: Yoghurt contains live bacteria that could contribute via modulation of the gut microbiota to its reported beneficial effects such as reduced body weight gain and lower incidence of type 2 diabetes. To date, the association between yoghurt consumption and the composition of the gut microbiota is underexplored. Here we used clinical variables, metabolomics, 16S rRNA and shotgun metagenomic sequencing data collected on over 1000 predominantly female UK twins to define the link between the gut microbiota and yoghurt-associated health benefits. RESULTS: According to food frequency questionnaires (FFQ), 73% of subjects consumed yoghurt. Consumers presented a healthier diet pattern (healthy eating index: beta = 2.17 ± 0.34; P = 2.72x10-10) and improved metabolic health characterised by reduced visceral fat (beta = -28.18 ± 11.71 g; P = 0.01). According to 16S rRNA gene analyses and whole shotgun metagenomic sequencing approach consistent taxonomic variations were observed with yoghurt consumption. More specifically, we identified higher abundance of species used as yoghurt starters Streptococcus thermophilus (beta = 0.41 ± 0.051; P = 6.14x10-12) and sometimes added Bifidobacterium animalis subsp. lactis (beta = 0.30 ± 0.052; P = 1.49x10-8) in the gut of yoghurt consumers. Replication in 1103 volunteers from the LifeLines-DEEP cohort confirmed the increase of S. thermophilus among yoghurt consumers. Using food records collected the day prior to faecal sampling we showed than an increase in these two yoghurt bacteria could be transient. Metabolomics analysis revealed that B. animalis subsp. lactis was associated with 13 faecal metabolites including a 3-hydroxyoctanoic acid, known to be involved in the regulation of gut inflammation. CONCLUSIONS: Yoghurt consumption is associated with reduced visceral fat mass and changes in gut microbiome including transient increase of yoghurt-contained species (i.e. S. thermophilus and B. lactis).

Comparison Between Full-Length 16S rRNA Metabarcoding and Whole Metagenome Sequencing Suggests the Use of Either Is Suitable for Large-Scale Microbiome Studies.

Since the number of studies of the microbial communities related to food and food-associated matrices almost completely reliant on next-generation sequencing techniques is rising, evaluations of these high-throughput methods are critical. Currently, the two most used sequencing methods to profile the microbiota of complex samples, including food and food-related matrices, are the 16S ribosomal RNA (rRNA) metabarcoding and the whole metagenome sequencing (WMS), both of which are powerful tools for the monitoring of foodborne pathogens and the investigation of the microbiome. Herein, the microbial profiles of 20 bulk tank milk filters from different dairy farms were investigated using both the full-length 16S (FL-16S) rRNA metabarcoding, a third-generation sequencing method whose application in food and food-related matrices is yet in its infancy, and the WMS, to evaluate the correlation and the reliability of these two methods to explore the microbiome of food-related matrices. Metabarcoding and metagenomic data were generated on a MinION platform (Oxford Nanopore Technologies) and on a Illumina NovaSeq 6000 platform, respectively. Our findings support the greater resolution of WMS in terms of both increased detection of bacterial taxa and enhanced detection of diversity; in contrast, FL-16S rRNA metabarcoding has proven to be a promising, less expensive, and more practical tool to profile most abundant taxa. The significant correlation of the two technologies both in terms of taxa diversity and richness, together with the similar profiles defined for both highly abundant taxa and core microbiomes, including Acinetobacter, Bacillus, and Escherichia genera, highlights the possible application of both methods for different purposes. This study allowed the first comparison of FL-16S rRNA sequencing and WMS to investigate the microbial composition of a food-related matrix, pointing out the advantageous use of FL-16S rRNA to identify dominant microorganisms and the superior power of WMS for the taxonomic detection of low abundant microorganisms and to perform functional analysis of the microbial communities.

Responses of microbial function, biomass and heterotrophic respiration, and organic carbon in fir plantation soil to successive nitrogen and phosphorus fertilization.

Carbon dioxide (CO2) emissions from forest ecosystems originate largely from soil respiration, and microbial heterotrophic respiration plays a critical role in determining organic carbon (C) stock. This study investigated the impacts of successive nitrogen (N) and phosphorus (P) fertilization after 9 years on soil organic C stock; CO2 emission; and microbial biomass, community, and function in a Chinese fir plantation. The annual fertilization rates were (1) CK, control without N or P fertilization; (2) N50, 50 kg N ha-1; (3) N100, 100 kg N ha-1; (4) P50, 50 kg P ha-1; (5) N50P50, 50 kg N ha-1 + 50 kg P ha-1; and (6) N100P50, 100 kg N ha-1 + 50 kg P ha-1. The N100P50 treatment had the highest cumulative soil CO2 emissions, but the CK treatment had the lowest cumulative soil CO2 emissions among all treatments. The declines of soil organic C (SOC) after successive 9-year fertilization were in the order of 100 kg N ha-1 year-1 > 50 kg N ha-1 year-1 > CK. Compared to the CK treatment, successive N fertilization significantly changed soil microbial communities at different application rates and increased the relative gene abundances of glycoside hydrolases, glycosyl transferases, carbohydrate-binding modules, and polysaccharide lyases at 100 kg N ha-1 year-1. Relative to P fertilization alone (50 kg P ha-1 year-1), combined N and P fertilization significantly altered the soil microbial community structure and favored more active soil microbial metabolism. Microbial community and metabolism changes caused by N fertilization could have enhanced CO2 emission from heterotrophic respiration and eventually led to the decrease in organic C stock in the forest plantation soil. KEY POINTS: • N fertilization, alone or with P, favored more active microbial metabolism genes. • 100 kg N ha-1 fertilization significantly changed microbial community and function. • N fertilization led to a "domino effect" on the decrease of soil C stock.

MegaPath: sensitive and rapid pathogen detection using metagenomic NGS data.

BACKGROUND: Next-generation sequencing (NGS) enables unbiased detection of pathogens by mapping the sequencing reads of a patient sample to the known reference sequence of bacteria and viruses. However, for a new pathogen without a reference sequence of a close relative, or with a high load of mutations compared to its predecessors, read mapping fails due to a low similarity between the pathogen and reference sequence, which in turn leads to insensitive and inaccurate pathogen detection outcomes. RESULTS: We developed MegaPath, which runs fast and provides high sensitivity in detecting new pathogens. In MegaPath, we have implemented and tested a combination of polishing techniques to remove non-informative human reads and spurious alignments. MegaPath applies a global optimization to the read alignments and reassigns the reads incorrectly aligned to multiple species to a unique species. The reassignment not only significantly increased the number of reads aligned to distant pathogens, but also significantly reduced incorrect alignments. MegaPath implements an enhanced maximum-exact-match prefix seeding strategy and a SIMD-accelerated Smith-Waterman algorithm to run fast. CONCLUSIONS: In our benchmarks, MegaPath demonstrated superior sensitivity by detecting eight times more reads from a low-similarity pathogen than other tools. Meanwhile, MegaPath ran much faster than the other state-of-the-art alignment-based pathogen detection tools (and compariable with the less sensitivity profile-based pathogen detection tools). The running time of MegaPath is about 20 min on a typical 1 Gb dataset.

Altered gut microbiota and mucosal immunity in patients with schizophrenia.

Evidence shows that gut microbiota may play important roles in schizophrenia pathogenesis via the "gut-brain" axis, but the mechanisms remain unclear. Here, eighty-four patients with schizophrenia and 84 sex- and age-matched healthy controls were enrolled. Shotgun metagenomic sequencing and 16S rRNA sequencing were performed, and the gut microbiota-associated epitopes (MEs) were predicted, which, together with IgA content, were used to determine the gut microbiota composition associated with gut immune status. Patients with schizophrenia had significantly reduced gut microbiota richnesses compared with those of the healthy controls, and the gut microbiota compositions clearly distinguished the patients with schizophrenia from the healthy controls. Based on two-stage metagenomic-wide association studies, nineteen gut microbiota taxonomies were associated with schizophrenia, and the microbial dysbiosis (MD) index was calculated based on the abundance of differential taxonomies. We found that MD index was positively correlated with MEs diversity and gut IgA levels, and negatively correlated with gut microbiota richness. Glutamate synthase (GOGAT) was more active in the guts of patients with schizophrenia than in those of healthy controls, and high GOGAT activity was associated with altered gut microbiota taxonomies associated with gut IgA levels. Our results may imply a role of the microbiome in the etiology of schizophrenia and contribute to the development of microbiome targeted interventions for schizophrenia.

Metagenomic insights into microbial characterizations in explaining the distinction of biofilter performance during start-up.

As an effective alternative for dissolved nitrogen removal, biofilter closely associates its treatment performance to structural and/or operational conditions. In this study, a set of four different biofilters including MAVF (mature aerated vertical flow), NAVF (new aerated vertical flow), NVF (new non-aerated vertical flow), and BHF (baffled non-aerated horizontal flow) were employed to purify low C/N ratio (3.8) domestic wastewater. All the filters were packed with round ceramsite operated under varying hydraulic loading rates (HLRs) of 0.024-0.18 m/day. During the start-up, both the physicochemical and microbial characterizations were investigated. It was found that, carbon and nitrogen could achieve ideal removal in MAVF once added with further sedimentation, while phosphorus displayed an unsatisfactory sequestration in any of the four filters probably due to the high inflow load and/or lack of alternate anaerobic/aerobic conditions. Filter clustering based on percent removal and removal rate constant displayed a consistent pattern, which was similar to that based on taxa of phylum from 16S rRNA sequencing, or phylum/genus/species from shotgun metagenomic sequencing although there were obvious distinctions in taxa compositions among direct comparison. Meanwhile, gene function annotation revealed that filter clustering based on metabolic pathways was consistent with that based on purification performance. These consistencies might imply that the treatment performance was mainly determined by microbial degradation. The enrichment of specific functional microbes responsible for the degradation of certain pollutants, such as carbohydrates, matched well with the defined purification performance.

Shotgun metagenomic sequencing from Manao-Pee cave, Thailand, reveals insight into the microbial community structure and its metabolic potential.

BACKGROUND: Due to the cave oligotrophic environment, this habitat presents a challenge for microorganisms to colonize and thrive. However, it has been well documented that microorganisms play important roles in cave development. Survival of microbes in this unique habitat likely involves a broad range of adaptive capabilities. Recently, cave microbiomes all over the world are of great scientific interest. However, the majority of investigations focused mostly on small subunit ribosomal RNA (16S rRNA) gene, leaving the ecological role of the microbial community largely unknown. Here, we are particularly interested in exploring the taxonomic composition and metabolic potential of microorganisms in soil from Manao-Pee cave, a subterranean limestone cave in the western part of Thailand, by using high-throughput shotgun metagenomic sequencing. RESULTS: From taxonomic composition analysis using ribosomal RNA genes (rRNA), the results confirmed that Actinobacteria (51.2%) and Gammaproteobacteria (24.4%) were the dominant bacterial groups in the cave soil community. Metabolic potential analysis, based on six functional modules of the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, revealed that functional genes involved in microbial metabolisms are highly represented in this community (40.6%). To better understand how microbes thrive under unfavorable cave condition, we focused on microbial energy metabolism. The results showed that microbial genes involved in oxidative phosphorylation were the most dominant (28.8%) in Manao-Pee cave, and were followed by methane metabolism (20.5%), carbon fixation (16.0%), nitrogen metabolism (14.7%), and sulfur metabolism (6.3%). In addition, microbial genes involved in xenobiotic biodegradation (26 pathways) and in production of secondary metabolites (27 pathways) were also identified. CONCLUSION: In addition to providing information on microbial diversity, we also gained insights into microbial adaptations and survival strategies under cave conditions. Based on rRNA genes, the results revealed that bacteria belonging to the Actinobacteria and Gammaproteobacteria were the most abundant in this community. From metabolic potential analysis, energy and nutrient sources that sustain diverse microbial population in this community might be atmospheric gases (methane, carbon dioxide, nitrogen), inorganic sulfur, and xenobiotic compounds. In addition, the presence of biosynthetic pathways of secondary metabolites suggested that they might play important ecological roles in the cave microbiome.

Alteration of gut microbiota-associated epitopes in children with autism spectrum disorders.

BACKGROUND: Autism spectrum disorder (ASD) affects 1% of children and has no cure. Gastrointestinal (GI) problems are common in children with ASD, and although gut microbiota is known to play an important role in ASD through the gut-brain axis, the specific mechanism is unknown. Recent evidence suggests that gut microbiota may participate in the pathogenesis of ASD through immune- and inflammation-mediated pathways. Here, we identified potentially immunogenic epitopes derived from gut microbiota in stool samples from ASD children with and without GI problems and typically developing (TD) children. METHODS: Candidate gut microbiota-associated epitopes (MEs) were identified by blast shotgun metagenomic sequencing of fecal samples from 43 ASD children (19 with and 24 without GI involvement) and 31 sex- and age-matched typically developing (TD) children. Potentially immunogenic epitopes were screened against a predictive human Immune Epitope Database. The composition and abundance of candidate MEs were compared between the three groups of children. RESULTS: MEs identified in ASD children with GI problems were significantly more diverse than those in TD children. ME composition could discriminate between the three groups of children. We identified 34 MEs that were significantly more or less abundant in ASD children than TD children, most (29/34) of the differences in MEs were reduced in ASD and associated with abnormal gut IgA level and altered gut microbiota composition, these MEs were limited effected by clinical factors such as age, gender, and GI problems, of which eleven MEs were pathogenic microorganisms peptides with strong T or B cell response, nine MEs showed high homology to peptides from human self proteins associated with autoimmune disease occurrence, eliciting immune attack against hematopoietic stem cells and inhibition antigen binding. We also found that the abundance of five MEs were increased in ASD, including three human self proteins, gap junction alpha-1 (GJA1), paired box protein Pax-3 (PAX3) and eyes absent homolog 1 isoform 4 (EYA1) which associated with cancer, and a ME with homology to a Listeriolysin O peptide from the pathogenic bacterium Listeria monocytogenes was significantly increased in ASD children compared with TD children. CONCLUSIONS: Our findings demonstrate the abnormal of MEs composition in the gut of children with ASD, moreover, the abnormality in MEs composition was associated with abnormal gut IgA levels and altered gut microbiota composition, this abnormality also suggests that there may be abnormalities in intestinal immunity in children with ASD; In all, thirty-four MEs identified were potential biomarker of ASD, and alterations in MEs may contribute to abnormalities in gut immunity and/or homeostasis in ASD children. Further study of the MEs identified here may advance our understanding of the pathogenesis of ASD.

The first Taxus rhizosphere microbiome revealed by shotgun metagenomic sequencing.

In the present study, the shotgun high throughput metagenomic sequencing was implemented to globally capture the features of Taxus rhizosphere microbiome. Total reads could be assigned to 6925 species belonging to 113 bacteria phyla and 301 species of nine fungi phyla. For archaea and virus, 263 and 134 species were for the first time identified, respectively. More than 720,000 Unigenes were identified by clean reads assembly. The top five assigned phyla were Actinobacteria (363,941 Unigenes), Proteobacteria (182,053), Acidobacteria (44,527), Ascomycota (fungi; 18,267), and Chloroflexi (15,539). KEGG analysis predicted numerous functional genes; 7101 Unigenes belong to "Xenobiotics biodegradation and metabolism." A total of 12,040 Unigenes involved in defense mechanisms (e.g., xenobiotic metabolism) were annotated by eggNOG. Talaromyces addition could influence not only the diversity and structure of microbial communities of Taxus rhizosphere, but also the relative abundance of functional genes, including metabolic genes, antibiotic resistant genes, and genes involved in pathogen-host interaction, bacterial virulence, and bacterial secretion system. The structure and function of rhizosphere microbiome could be sensitive to non-native microbe addition, which could impact on the pollutant degradation. This study, complementary to the amplicon sequencing, more objectively reflects the native microbiome of Taxus rhizosphere and its response to environmental pressure, and lays a foundation for potential combination of phytoremediation and bioaugmentation.

Oral microbiome associated with differential ratios of Porphyromonas gingivalis and Streptococcus cristatus.

Periodontitis has recently been defined as a dysbiotic disease caused by an imbalanced oral microbiota. The transition from commensal microbial communities to periodontitis-associated ones requires colonization by specific pathogens, including Porphyromonas gingivalis. We previously reported an antagonistic relationship between Streptococcus cristatus and P. gingivalis. To determine the role of S. cristatus in altering the interactions of P. gingivalis with other oral bacteria in a complex context, we collected dental plaque samples from patients with periodontitis and assigned them to two groups based on the ratios of S. cristatus and P. gingivalis. We then characterized the microbial profiles of the dental plaque samples using shotgun metagenomic sequencing and compared the oral microbial composition and functional capabilities of the group with high S. cristatus-P. gingivalis ratios with the low ratio group. Taxonomic annotation revealed significant differences in the microbial composition at both the genus and species levels between the low and high S. cristatus-P. gingivalis ratio groups. Notably, a higher microbial diversity was observed in the samples with low S. cristatus-P. gingivalis ratios. Furthermore, the antibiotic resistance gene profiles of the two groups were also distinct, with a significantly increased abundance of the genes in the dental plaque samples with low S. cristatus-P. gingivalis ratios. It, therefore, indicates that the S. cristatus-P. gingivalis ratios influenced the virulence potential of the oral microbiome. Our work shows that enhancing the S. cristatus-P. gingivalis ratio in oral microbial communities can be an attractive approach for revising the dysbiotic oral microbiome.IMPORTANCEPeriodontitis, one of the most common chronic diseases, is linked to several systemic diseases, such as cardiovascular disease and diabetes. Although Porphyromonas gingivalis is a keystone pathogen that causes periodontitis, its levels, interactions with accessory bacteria and pathobionts in the oral microbiome, and its association with the pathogenic potential of the microbial communities are still not well understood. In this study, we revealed the role of Streptococcus cristatus and the ratios of S. cristatus and P. gingivalis in modulating the oral microbiome to facilitate a deeper understanding of periodontitis and its progression. The study has important clinical implications as it laid a foundation for developing novel non-antibiotic therapies against P. gingivalis and improving the efficiency of periodontal treatments.