Integrating taxonomic, functional, and strain-level profiling of diverse microbial communities with bioBakery 3

Exclusive breastfeeding is associated with the gut microbiome maturation in infants according to delivery mode

Exclusive breastfeeding (EBF) plays a crucial role in infant gut microbiome assembly and development. However, few studies have investigated the effects of EBF in restoring a perturbed microbiome. In this study, we applied whole metagenomic sequencing to assess the gut microbiome assembly in 525 Brazilian infants from 3 to 9 months of age of the Germina Cohort, demonstrating the early determinants of microbial taxonomy and function modulation. Our analysis shows that EBF alters the relative abundance of genes related to the microbiome taxonomy and function, with effects varying by delivery mode. EBF alters the pattern of carbohydrates, lipid metabolism, and cell structure pathways depending on the delivery mode. The microbiome age is closer to chronological infant age in EBF than in non-EBF infants, meaning a lower microbiome maturation index (MMI). Using a complementary machine learning approach, we show that Escherichia coli, Ruminococcus gnavus, and Clostridium neonatale, as well as vitamin K and o-antigen pathways contribute strongly to EBF prediction. Moreover, EBF influences the microbiome maturation in early life, toward a microbiome age more similar to the chronological infant's age.

Metagenomic source tracking after microbiota transplant therapy

Reliable engraftment assessment of donor microbial communities and individual strains is an essential component of characterizing the pharmacokinetics of microbiota transplant therapies (MTTs). Recent methods for measuring donor engraftment use whole-genome sequencing and reference databases or metagenome-assembled genomes (MAGs) to track individual bacterial strains but lack the ability to disambiguate DNA that matches both donor and patient microbiota. Here, we describe a new, cost-efficient analytic pipeline, MAGEnTa, which compares post-MTT samples to a database comprised MAGs derived directly from donor and pre-treatment metagenomic data, without relying on an external database. The pipeline uses Bayesian statistics to determine the likely sources of ambiguous reads that align with both the donor and pre-treatment samples. MAGEnTa recovers engrafted strains with minimal type II error in a simulated dataset and is robust to shallow sequencing depths in a downsampled dataset. Applying MAGEnTa to a dataset from a recent MTT clinical trial for ulcerative colitis, we found the results to be consistent with 16S rRNA gene SourceTracker analysis but with added MAG-level specificity. MAGEnTa is a powerful tool to study community and strain engraftment dynamics in the development of MTT-based treatments that can be integrated into frameworks for functional and taxonomic analysis.

Gut microbiota drives structural variation of exogenous probiotics to enhance colonization

Probiotics encounter colonization resistance from native gut microbiomes, affecting their effectiveness. Genetic engineering of probiotics lacks universal applicability, as gut microbiotas are highly individualized. Here, we employed probiotic Lactiplantibacillus plantarum HNU082 (Lp082) to test whether Lp082 gut-adapted mutants can resolve colonization resistance in a new gut environment. Relying on culture-based methods and metagenomics, two distinct evolutionary clades of Lp082 in mice gut were observed, where one clade, which acquired more mutations, exhibited a longer survival time. However, these Lp082 isolates carrying many single nucleotide variants (SNVs) still exhibited phenotypic inconsistencies, with 13 strains of enhanced acid resistance. Thus, nanopore sequencing was proposed to identify structural variations (SVs). Among them, 12 strains had the Cro/C1-type HTH DNA-binding domain insertion, which enhanced growth and reproduction under bile salt stress, thereby increasing colonization time and quantity in the gut. The gut domestication process can drive probiotics to undergo many SNVs and SVs, thereby enhancing their colonization ability, which provides new insights into the colonization mechanisms and offers an ecology-based strategy.

A novel framework for assessing causal effect of microbiome on health: long-term antibiotic usage as an instrument

Assessing causality is undoubtedly one of the key questions in microbiome studies for the upcoming years. Since randomized trials in human subjects are often unethical or difficult to pursue, analytical methods to derive causal effects from observational data deserve attention. As simple covariate adjustment is not likely to account for all potential confounders, the idea of instrumental variable (IV) analysis is worth exploiting. Here we propose a novel framework of antibiotic instrumental variable regression (AB-IVR) for estimating the causal relationships between microbiome and various diseases. We rely on the recent studies showing that antibiotic treatment has a cumulative long-term effect on the microbiome, resulting in individuals with higher antibiotic usage to have a more perturbed microbiome. We apply the AB-IVR method on the Estonian Biobank data and show that the microbiome has a causal role in numerous diseases including migraine, depression and irritable bowel syndrome. We show with a plethora of sensitivity analyses that the identified causal effects are robust and propose ways for further methodological developments.

Urease in acetogenic Lachnospiraceae drives urea carbon salvage in SCFA pools

The gut microbiota produces short-chain fatty acids (SCFA) and acidifies the proximal colon which inhibits enteric pathogens. However, for many microbiota constituents, how they themselves resist these stresses is unknown. The anaerobic Lachnospiraceae family, which includes the acetogenic genus Blautia, produce SCFA, are genomically diverse, and vary in their capacity to acidify culture media. Here, we investigated how Lachnospiraceae tolerate pH stress and found that subunits of urease were associated with acidification in a random forest model. Urease cleaves urea into ammonia and carbon dioxide, however the role of urease in the physiology of Lachnospiraceae is unknown. We demonstrate that urease-encoding Blautia show urea-dependent changes in SCFA production, acidification, growth, and, strikingly, urease encoding Blautia directly incorporate the carbon from urea into SCFAs. In contrast, ureolytic Klebsiella pneumoniae or Proteus mirabilis do not show the same urea-dependency or carbon salvage. In agreement, the combination of urease and acetogenesis functions is rare in gut taxa. We find that Lachnospiraceae urease and acetogenesis genes can be co-expressed in healthy individuals and colonization of mice with a ureolytic Blautia reduces urea availability in colon contents demonstrating Blautia urease activity in vivo. In human and mouse microbial communities, the acetogenic recycling of urea carbon into acetate by Blautia leads to the incorporation of urea carbon into butyrate indicating carbon salvage into broader metabolite pools. Altogether, this shows that urea plays a central role in the physiology of health-associated Lachnospiraceae which use urea in a distinct manner that is different from that of ureolytic pathogens.

High-resolution analysis of the treated coeliac disease microbiome reveals strain-level variation

BACKGROUND

Coeliac disease (CeD) is an immune-mediated disorder primarily affecting the small intestine, characterized by an inflammatory immune reaction to dietary gluten. CeD onset results from a multifaceted interplay of genetic and environmental factors. While recent data show that alterations in gut microbiome composition could play an important role, many current studies are constrained by small sample sizes and limited resolution.

METHODS

To address these limitations, we analyzed fecal gut microbiota from two Dutch cohorts, CeDNN (128 treated CeD patients (tCeD), 106 controls) and the Lifelines Dutch Microbiome Project (24 self-reported tCeD, 654 controls), using shotgun metagenomic sequencing. Self-reported IBS (570 cases, 1710 controls) and IBD (93 cases, 465 controls) were used as comparative conditions of the gastrointestinal tract. Interindividual variation within the case and control groups was calculated at whole microbiome and strain level. Finally, species-specific gene repertoires were analyzed in tCeD patients and controls.

RESULTS

Within-individual microbiome diversity was decreased in patients with self-reported IBS and IBD but not in tCeD patients. Each condition displayed a unique microbial pattern and, in addition to confirming previously reported microbiome associations, we identify an increase in the levels of Clostridium sp. CAG:253, Roseburia hominis, and Eggerthella lenta, amongst others. We further show that the observed changes can partially be explained by gluten-free diet adherence. We also observe increased interindividual variation of gut microbiome composition among tCeD patients and a higher bacterial mutation frequency in tCeD that contributes to higher interindividual variation at strain level. In addition, the immotile European subspecies of Eubacterium rectale, which has a distinct carbohydrate metabolism potential, was nearly absent in tCeD patients.

CONCLUSION

Our study sheds light on the complex interplay between the gut microbiome and CeD, revealing increased interindividual variation and strain-level variation in tCeD patients. These findings expand our understanding of the microbiome's role in intestinal health and disease.

Best practices for developing microbiome-based disease diagnostic classifiers through machine learning

The human gut microbiome, crucial in various diseases, can be utilized to develop diagnostic models through machine learning (ML). The specific tools and parameters used in model construction such as data preprocessing, batch effect removal and modeling algorithms can impact model performance and generalizability. To establish an generally applicable workflow, we divided the ML process into three above-mentioned steps and optimized each sequentially using 83 gut microbiome cohorts across 20 diseases. We tested a total of 156 tool-parameter-algorithm combinations and benchmarked them according to internal- and external- AUCs. At the data preprocessing step, we identified four data preprocessing methods that performed well for regression-type algorithms and one method that excelled for non-regression-type algorithms. At the batch effect removal step, we identified the "ComBat" function from the sva R package as an effective batch effect removal method and compared the performance of various algorithms. Finally, at the ML algorithm selection step, we found that Ridge and Random Forest ranked the best. Our optimized work flow performed similarly comparing with previous exhaustive methods for disease-specific optimizations, thus is generally applicable and can provide a comprehensive guideline for constructing diagnostic models for a range of diseases, potentially serving as a powerful tool for future medical diagnostics.

Integrative metagenomics and metabolomics reveal age-associated gut microbiota and metabolite alterations in a hamster model of COVID-19

Aging is a key contributor of morbidity and mortality during acute viral pneumonia. The potential role of age-associated dysbiosis on disease outcomes is still elusive. In the current study, we used high-resolution shotgun metagenomics and targeted metabolomics to characterize SARS-CoV-2-associated changes in the gut microbiota from young (2-month-old) and aged (22-month-old) hamsters, a valuable model of COVID-19. We show that age-related dysfunctions in the gut microbiota are linked to disease severity and long-term sequelae in older hamsters. Our data also reveal age-specific changes in the composition and metabolic activity of the gut microbiota during both the acute phase (day 7 post-infection, D7) and the recovery phase (D22) of infection. Aged hamsters exhibited the most notable shifts in gut microbiota composition and plasma metabolic profiles. Through an integrative analysis of metagenomics, metabolomics, and clinical data, we identified significant associations between bacterial taxa, metabolites and disease markers in the aged group. On D7 (high viral load and lung epithelial damage) and D22 (body weight loss and fibrosis), numerous amino acids, amino acid-related molecules, and indole derivatives were found to correlate with disease markers. In particular, a persistent decrease in phenylalanine, tryptophan, glutamic acid, and indoleacetic acid in aged animals positively correlated with poor recovery of body weight and/or lung fibrosis by D22. In younger hamsters, several bacterial taxa (Eubacterium, Oscillospiraceae, Lawsonibacter) and plasma metabolites (carnosine and cis-aconitic acid) were associated with mild disease outcomes. These findings support the need for age-specific microbiome-targeting strategies to more effectively manage acute viral pneumonia and long-term disease outcomes.

Environmental microbiome mapping in poultry processing chain and assessment of microbial dynamics in response to different storage conditions

Poultry production chain comprises a complex network involving various stages from rearing to the final distribution of poultry products. This study explores the intricate dynamics within this chain, using shotgun metagenomics, particularly focusing on taxonomic and functional composition of the microbiome, antibiotic resistance and virulence potential. Moreover, the study of the impact of different packaging and storage conditions provides insights into how diverse packaging strategies and storage temperature can impact the shelf-life of chicken meat. Microbiome mapping in poultry processing facility revealed the dominance of Brochothrix thermosphacta, Pseudomonas fragi and Psychrobacter immobilis on poultry-based products and industrial surfaces. Indeed, surfaces of equipment and tools have a significant impact on the microbial composition of the final food products. Furthermore, the study of the microbiome dynamics in chicken meat stored in different packaging (air, modified atmosphere, under vacuum) and temperatures (0, 4 and 10 °C) revealed temperature-dependent microbiota shifts in chicken meat, highlighting specific spoilage organisms (SSOs) in the different packaging methods. Additionally, our results showed that poultry-based products and industrial surfaces belonging to carcasses processing area hosted elevated levels of Antibiotic Resistance Genes, mainly associated with resistance to aminoglycosides, β-lactams, MLSPs (which includes macrolides, lincosamides, streptogramins and pleuromutilins) amphenicols and tetracyclines classes and several Virulence-associated genes related to adherence, biofilm, effector delivery system, motility, nutritional/metabolic factors and regulation. Finally, our findings underscored a notably mobile resistome, showing multiple AR class correlated with mobile elements. This poses a considerable risk, emphasizing the urgent need for proactive measures in addressing potential antibiotic resistance genes dissemination in the poultry chain.

Alpha-aminobutyric acid ameliorates diet-induced metabolic dysfunction-associated steatotic liver disease (MASLD) progression in mice via enhancing AMPK/SIRT1 pathway and modulating the gut-liver axis

Alpha-aminobutyric acid (ABA) is a nonproteinogenic amino acid, a metabolite which could be generated from the metabolism of methionine, threonine, serine and glycine or as a gut-microbiome-derived metabolite. Changes in ABA levels have been embroiled in metabolic dysfunction-associated steatotic liver disease (MASLD) intervention studies, but their relation to MASLD pathogenesis remains unclear. Hence, this present study aimed to investigate the effect of oral ABA supplementation on the progression of a high fat/high cholesterol diet (HFD) induced MASLD mice model. ABA was found to remodel the gut microbiome composition and ameliorate MASLD parameters in HFD-fed mice. ABA mitigated HFD-induced gain in liver weight, hepatic steatosis, insulin resistance, serum and hepatic triglyceride levels, and liver cholesterol levels. Modulation of lipid metabolism was observed in the liver, in which expression of proteins and/or genes involved in de novo lipogenesis were suppressed, while those involved in fatty acid oxidation and autophagy were upregulated together with cellular antioxidant capacity, in addition to the enhancement of the AMPK/SIRT1 pathway. ABA reshaped the gut composition by enriching nine bacterial species, including Helicobacter hepaticus, Desulfovibrio sp. G11, Parabacteroides distasonis, and Bacteroides fragilis, while diminishing the abundance of 16 species, which included four Helicobacter species. KEGG pathway analysis of microbial functions found that ABA impeded secondary bile acid biosynthesis - which was reflected in the faecal BA composition analysis. Notably, ABA also inhibited ileal FXR-Fgf15 signaling, allowing for increased hepatic Cyp7a1 expression to eliminate cholesterol buildup in the liver. Overall, our findings indicate that ABA could be used as a promising therapeutic approach for the intervention of MASLD.

Significant effects of earthworm species on antibiotic resistome in livestock manure as revealed by metagenomic analysis

Animal-derived antibiotic resistance genes (ARGs) have emerged as a critical threat, while vermicomposting has been recognized as an effective strategy for reducing ARGs. However, the efficacy of different earthworm species in reducing ARGs remains poorly understood. In this study, 72 vermicompost and earthworm gut samples were collected from various earthworm farms to evaluate the impact of vermicomposting with different earthworm species on ARGs via metagenomic analysis. Approximately 28 ARG types were detected in gut and vermicompost samples. There were significant differences in ARGs among the four species of earthworm composting systems (p < 0.05), and each species possessed its dominant ARGs and microbes. Proteobacteria represented the predominant bacterial phylum within the gut microbiota of Pheretima guillelmi (46.89 %) and Eisenia fetida (48.42 %), whereas Euryarchaeota (36.71 %) and Actinobacteria (39.42 %) were the most abundant in Perionyx excavatus and Eudrilus eugeniae, respectively. The overall abundance of ARGs in vermicompost processed by Eisenia fetida (0.18 copies16S rRNA gene copies) was lower than that observed in other earthworm species (0.23-0.39 copies/16S rRNA gene copies), with gut microbial identified as a key determinant of variations in ARG reduction. These findings provide valuable insights into selecting suitable earthworm species to promote ARG degradation, thus contributing to the decrease in ARG dissemination risks in agricultural ecosystems.

Prebiotic supplementation in patients with type 1 diabetes: study protocol for a randomised controlled trial in Canada

INTRODUCTION

Type 1 diabetes (T1D) mellitus is caused by autoimmune destruction of insulin-producing beta-cells, requiring exogenous insulin to sustain life. Achieving near normal blood glucose levels with insulin, a primary goal of diabetes management, carries a significant risk of hypoglycaemia. There is compelling evidence that an abnormal gut microbiota or dysbiosis can increase intestinal permeability (IP) and contribute to dysglycaemia seen in T1D. Given that prebiotic fibre can mitigate dysbiosis, reduce IP and improve glycaemic control, we hypothesise that microbial changes induced by prebiotics contribute to gut and endocrine adaptations that reduce glucose fluctuations, including less hypoglycaemia. In a pilot study, we showed that in children who had T1D for at least 1 year, a 3-month course of prebiotic fibre significantly reduced the frequency of hypoglycaemia. The prebiotic group had an increase in Bifidobacterium with a moderate improvement in IP. Importantly, the prebiotic group maintained their serum C peptide level (marker of residual beta cell function) while the placebo group saw a drop. Given that preserving endogenous beta cell function in patients with T1D, particularly in the first year of diagnosis, reduces hypoglycaemia and glycaemic variability, we propose to examine the effect of prebiotic supplementation in patients with T1D.

METHODS AND ANALYSIS

This is a multicentre, randomised, double-blind, placebo-controlled study. Individuals (n=144) with T1D will be randomised 1:1 for 6 months to prebiotic (oligofructose-enriched inulin) or placebo (isocaloric maltodextrin). Participants will have three in-person study visits at baseline, 3 months and 6 months. The primary outcome, frequency of hypoglycaemia, will be determined from continuous glucose monitor (CGM) reports and patient blood glucose logs. Secondary outcomes will include glycaemic variability, time-in-range, glycated haemoglobin, stimulated C peptide, IP, serum inflammatory markers, quality of life and fear of hypoglycaemia ratings, as well as gut microbiome and metabolomics analysis. At 9 months, participant CGM data will be used to assess frequency of hypoglycaemia and glycaemic variability at 3 months postintervention.

ETHICS AND DISSEMINATION

The study received ethical approval from the University of Calgary Conjoint Health Research Ethics Board (REB21-0852). The University of Alberta subsite was granted ethical approval under the province of Alberta's research ethics reciprocity agreement as a participating site (REB21-0852; pSite00000066). The University of Saskatchewan subsite was granted ethical approval by the Biomedical Research Ethics Board (#4149). Trial findings will be disseminated through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

clinicaltrials.gov NCT04963777.

Integrated multi-omics reveals different host crosstalk of atopic dermatitis-enriched Bifidobacterium longum Strains

The infant gut microbiome is essential for long-term health and is linked to atopic dermatitis (AD), although the underlying mechanisms are not fully understood. This study investigated gut microbiome-host interactions in 31 infants with AD and 29 healthy controls using multi-omics approaches, including metagenomic, host transcriptomic, and metabolomic analyses. Microbial diversity was significantly altered in AD, with Bifidobacterium longum and Clostridium innocuum associated with these changes. At the strain-level, only B. longum differed significantly between groups, with pangenome analyses identifying genetic variations potentially affecting amino acid and lipid metabolites. Notably, B. longum subclade I, which was more prevalent in healthy controls, correlated with host transcriptomic pathways involved in phosphatidylinositol 3-kinase-AKT signaling and neuroactive ligand-receptor pathways, as well as specific metabolites, including tetrahydrocortisol and ornithine. These findings highlight the role of B. longum strain-level variation in infants, offering new insights into microbiome-host interactions related to AD.

Investigating Plasma Metabolomics and Gut Microbiota Changes Associated With Parkinson Disease: A Focus on Caffeine Metabolism

BACKGROUND AND OBJECTIVES

Coffee intake is linked to a reduced risk of Parkinson disease (PD), but whether this effect is mediated by gut microbiota and metabolomic changes remains unclear. This study examines PD-associated metabolomic shifts, caffeine metabolism, and their connection to gut microbiome alterations in a multicenter study.

METHODS

We conducted an untargeted serum metabolomic assay using liquid chromatography with high-resolution mass spectrometry on an exploratory cohort recruited from National Taiwan University Hospital (NTUH). A targeted metabolomic assay focusing on caffeine and its 12 downstream metabolites was conducted and validated in an independent cohort from University Malaya Medical Centre (UMMC). In the exploratory cohort, the association of each caffeine metabolite with gut microbiota changes was investigated by metagenomic shotgun sequencing. A clustering-based approach was used to correlate microbiome changes with plasma caffeine metabolite level and clinical severity. Body mass index, antiparkinsonism medication use, and dietary habits (including coffee and tea intake) were recorded.

RESULTS

Sixty-three patients with PD and 54 controls from NTUH formed the exploratory cohort while 36 patients with PD and 20 controls from UMMC served as an validation cohort to replicate the plasma caffeine findings. A total of 5,158 metabolites were detected from untargeted metabolomic analysis, with 3,131 having high confidence for analysis. Compared with controls, the abundance of 56 metabolites was significantly higher and that of 7 metabolites was significantly lower (adjusted p < 0.05 and log2 fold change >1) in patients with PD. Caffeine metabolism was significantly lower in patients with PD (p = 0.0013), and serum levels of caffeine and its metabolites negatively correlated with motor severity (p < 0.01). Targeted metabolomic analysis confirmed reduced levels of caffeine and its metabolites, including theophylline, paraxanthine, 1,7-dimethyluric acid, and 5-acetylamino-6-amino-3-methyluracil, in patients with PD; these findings were replicated in the validation cohort (p < 0.05). A clustering approach found that 56 microbiome species enriched in patients with PD negatively correlated with caffeine and its metabolites paraxanthine and theophylline (both p < 0.05), notably Clostridium sp000435655, Acetatifactor sp900066565, Oliverpabstia intestinalis, and Ruminiclostridium siraeum.

DISCUSSION

This study identifies PD-related changes in microbial-caffeine metabolism compared with controls. Our findings offer insights for future functional research on caffeine-microbiome interactions in PD.

Small amounts of misassembly can have disproportionate effects on pangenome-based metagenomic analyses

Individual genes from microbiomes can drive host-level phenotypes. To help identify such candidate genes, several recent tools estimate microbial gene copy numbers directly from metagenomes. These tools rely on alignments to pangenomes, which, in turn, are derived from the set of all individual genomes from one species. While large-scale metagenomic assembly efforts have made pangenome estimates more complete, mixed communities can also introduce contamination into assemblies, and it is unknown how robust pangenome-based metagenomic analyses are to these errors. To gain insight into this problem, we re-analyzed a case-control study of the gut microbiome in cirrhosis, focusing on commensal Clostridia previously implicated in this disease. We tested for differentially prevalent genes in the Lachnospiraceae and then investigated which were likely to be contaminants using sequence similarity searches. Out of 86 differentially prevalent genes, we found that 33 (38%) were probably contaminants originating in taxa such as Veillonella and Haemophilus, unrelated genera that were independently correlated with disease status. Our results demonstrate that even small amounts of contamination in metagenome assemblies, below typical quality thresholds, can threaten to overwhelm gene-level metagenomic analyses. However, we also show that such contaminants can be accurately identified using a method based on gene-to-species correlation. After removing these contaminants, we observe that several flagellar motility gene clusters in the Lachnospira eligens pangenome are associated with cirrhosis status. We have integrated our analyses into an analysis and visualization pipeline, PanSweep, that can automatically identify cases where pangenome contamination may bias the results of gene-resolved analyses.IMPORTANCEMetagenome-assembled genomes, or MAGs, can be constructed without pure cultures of microbes. Large-scale efforts to build MAGs have yielded more complete pangenomes (i.e., sets of all genes found in one species). Pangenomes allow us to measure strain variation in gene content, which can strongly affect phenotype. However, because MAGs come from mixed communities, they can contaminate pangenomes with unrelated DNA; how much this impacts downstream analyses has not been studied. Using a metagenomic study of gut microbes in cirrhosis as our test case, we investigate how contamination affects analyses of microbial gene content. Surprisingly, even small, typical amounts of MAG contamination (<5%) result in disproportionately high levels of false positive associations (38%). Fortunately, we show that most contaminants can be automatically flagged and provide a simple method for doing so. Furthermore, applying this method reveals a new association between cirrhosis and gut microbial motility.

Improved detection of microbiome-disease associations via population structure-aware generalized linear mixed effects models (microSLAM)

Microbiome association studies typically link host disease or other traits to summary statistics measured in metagenomics data, such as diversity or taxonomic composition. But identifying disease-associated species based on their relative abundance does not provide insight into why these microbes act as disease markers, and it overlooks cases where disease risk is related to specific strains with unique biological functions. To bridge this knowledge gap, we developed microSLAM, a mixed-effects model and an R package that performs association tests that connect host traits to the presence/absence of genes within each microbiome species, while accounting for strain genetic relatedness across hosts. Traits can be quantitative or binary (such as case/control). MicroSLAM is fit in three steps for each species. The first step estimates population structure across hosts. Step two calculates the association between population structure and the trait, enabling detection of species for which a subset of related strains confer risk. To identify specific genes whose presence/absence across diverse strains is associated with the trait, step three models the trait as a function of gene occurrence plus random effects estimated from step two. Applying microSLAM to 710 gut metagenomes from inflammatory bowel disease (IBD) samples, we discovered 56 species whose population structure correlates with IBD, meaning that different lineages are found in cases versus controls. After controlling for population structure, 20 species had genes significantly associated with IBD. Twenty-one of these genes were more common in IBD patients, while 32 genes were enriched in healthy controls, including a seven-gene operon in Faecalibacterium prausnitzii that is involved in utilization of fructoselysine from the gut environment. The vast majority of species detected by microSLAM were not significantly associated with IBD using standard relative abundance tests. These findings highlight the importance of accounting for within-species genetic variation in microbiome studies.

Shotgun metagenomic composition, microbial interactions and functional insights into the uterine microbiome of postpartum dairy cows with clinical and subclinical endometritis

Clinical endometritis (CE) is associated with bacterial pathogens while the same has not been proved about subclinical endometritis (SCE). We aimed to use shotgun metagenomic sequencing to investigate the associations between potentially unidentified pathogens and SCE. Uterine cytobrush samples from multiparous Holstein cows (n = 23) were taken at 21 days in milk (DIM) and sequenced via the Illumina shotgun platform. At 36 DIM, the cows were diagnosed as CE (n = 7), SCE (n = 7), or healthy (n = 9). We did not find differences in the alpha and beta diversity of bacteria and eukaryotes among the health groups. Relative abundance of typical pathogens i.e. Fusobacterium, Peptoniphilus, Peptostreptococcus, and Trueperella was greater in CE than healthy controls. We did not find evidence of eukaryotic or viral association in infection, yet, distinct patterns of bacterial co-occurrence were observed among pathogenic and non-pathogenic bacteria. In CE cows, Wnt/catenin pathway had lower abundance than SCE or healthy cows. Our findings support that CE is characterized by domination of pathogenic bacteria that intercorrelate, whereas SCE is not associated with bacterial colonization.

Association of distinct microbial and metabolic signatures with microscopic colitis

Microscopic colitis (MC) is a chronic inflammatory disease of the large intestine that primarily affects older adults and presents with chronic diarrhea. The etiology is unknown and there are currently no FDA approved medications or biomarkers for treatment or monitoring of the disease. Emerging evidence have implicated the gut microbiome and metabolome disturbances in MC pathogenesis. We conduct a comprehensive analysis of gut microbial and metabolic changes in a cohort of 683 participants, including 131 patients with active MC, 159 with chronic diarrhea, and 393 age- and sex-matched controls without diarrhea. Stool microbiome and metabolome are profiled using whole-genome shotgun metagenomic sequencing and ultra-high performance liquid chromatography-mass spectrometry, respectively. Compared to controls, eight microbial species including pro-inflammatory oral-typical Veillonella dispar and Haemophilus parainfluenzae, and 11 species, including anti-inflammatory Blautia glucerasea and Bacteroides stercoris are enriched and depleted in MC, respectively. Pro-inflammatory metabolites, including lactosylceramides, ceramides, lysophospholipids, and lysoplasmalogens, are enriched in active MC. Multi-omics analyses reveal robust associations between microbial species, metabolic pathways, and metabolites, suggesting concordant disruptions in MC. Here, we show distinct shifts in gut microbiome and metabolome in MC that can inform the development of non-invasive biomarkers and novel therapeutics.

Early-life development of the gut virome and plasmidome: A longitudinal study in cesarean-born infants

Mobile genetic elements (MGE) are critical yet understudied determinants of gut microbiome composition. In this secondary analysis of a randomized controlled trial (NCT06030713), we characterized the gut virome and plasmidome in 195 samples from 28 mother-infant dyads delivered by cesarean section. Infant mobilome increases in richness over the first 6 postnatal weeks, demonstrating high individual-specificity and temporal stability, establishing a personal persistent mobilome. Formula-fed infants exhibit greater mobilome richness than breastfed infants, with plasmid composition being influenced by antibiotic exposure and birth weight. Plasmids constitute a reservoir of antibiotic resistance genes (ARG), with around 5% of infant gut plasmid taxonomic units carrying ARG. Notably, ARG profiles do not differ with antibiotic exposure at birth. Mother-infant sharing of viral and plasmid strains primarily occurs after 6 months of age. Overall, our integrative analysis offers insights into the dynamics, modulation, and origin of MGE in the developing gut microbiome.

Probiotics Mixture, Prohep: a Potential Adjuvant for Low-Dose Sorafenib in Metabolic Dysfunction-Associated Steatotic Liver Disease-Associated Hepatocellular Carcinoma Suppression Through Modulating Gut Microbiota

Targeting gut microbiota is an innovative approach to mitigate the development of metabolic dysfunction-associated steatotic liver disease-associated hepatocellular carcinoma (MASLD-HCC). This study aims to investigate the effects of Prohep, a probiotic mixture, both as a prophylactic measure and as an adjuvant therapy for low-dose sorafenib. A MASLD-HCC mice model was established by diethylnitrosamine (DEN) injection with feeding of a high-fat high-cholesterol (HFHC) diet. Gut microbiome profiles were later identified through shotgun sequencing. Our findings demonstrated that Prohep supplementation effectively suppressed MASLD-HCC development in mice. This protective effect was attributed to the modulation of gut microbiota and the increased production of short-chain fatty acids (SCFAs), propionate, and valerate. Prohep also activated AMPK, which decreased lipogenesis, reduced lipid uptake, and enhanced antioxidant enzyme expressions. Additionally, the cancer proliferation pathway PI3K/mTOR was inhibited in response to Prohep treatment. As an adjuvant therapy, Prohep improved the efficacy of low-dose sorafenib, as indicated by reduced tumor counts, alleviated inflammation, and increased hepatic superoxide dismutase (SOD) expression. The combination led to enhanced butyrate production, contributing to the overall therapeutic effects, thanks to the gut microbiota modulatory effects of Prohep. These results underscore Prohep's anti-tumorigenic properties and its potential to enhance the therapeutic outcomes of low-dose sorafenib in MASLD-HCC treatment. The study highlights the importance of gut microbiota modulation for developing effective neoadjuvant therapies and long-term management strategies for MASLD-HCC.

Changing Gastrointestinal Transit Time Alters Microbiome Composition and Bile Acid Metabolism: A Cross-Over Study in Healthy Volunteers

BACKGROUND

The specific influence of whole gut transit time (WGTT) on microbiome dynamics and bile acid metabolism remains unclear, despite links between changes in WGTT and certain gastrointestinal disorders. Our investigation aimed to determine the impact of WGTT changes on the composition of the fecal microbiome and bile acid profile.

METHODS

Healthy volunteers (n = 18) received loperamide, to decrease bowel movement frequency, and senna, a laxative, each over a 6-day period, in a randomized sequence, with a minimum 16-day interval between each treatment. Stool samples were analyzed for microbiome by shotgun sequencing and bile acid composition determined with high-performance liquid chromatography coupled to tandem mass spectrometry. Sera were examined for markers of bile acid synthesis.

KEY RESULTS

Senna or loperamide decreased or increased WGTT, respectively. Treatment altered stool characteristics, bowel movement frequency, and stool weight. The senna-treated group had increased primary and secondary fecal bile acids; serum levels of fibroblast growth factor 19 were significantly reduced. Increasing WGTT with loperamide led to an increase in bile salt hydrolase genes, along with elevated bacterial species richness (p = 0.04). Thirty-six species exhibiting significant differences were identified, several of which have notable implications for gut health. WGTT displayed negative correlations with total primary (particularly chenodeoxycholic acid) and secondary bile acids (ursodeoxycholic acid and glycochenodeoxycholic acid). Treatment-induced changes in microbiome composition and bile acid metabolism reverted back to baseline within 16 days.

CONCLUSION

Whole gut transit time changes significantly affect fecal microbiome composition and function, as well as bile acid composition and synthesis in healthy subjects. This consideration is likely to have long-term implications.

Improving gut virome comparisons using predicted phage host information

The human gut virome is predominantly made up of bacteriophages (phages), viruses that infect bacteria. Metagenomic studies have revealed that phages in the gut are highly individual specific and dynamic. These features make it challenging to perform meaningful cross-study comparisons. While several taxonomy frameworks exist to group phages and improve these comparisons, these strategies provide little insight into the potential effects phages have on their bacterial hosts. Here, we propose the use of predicted phage host families (PHFs) as a functionally relevant, qualitative unit of phage classification to improve these cross-study analyses. We first show that bioinformatic predictions of phage hosts are accurate at the host family level by measuring their concordance to Hi-C sequencing-based predictions in human and mouse fecal samples. Next, using phage host family predictions, we determined that PHFs reduce intra- and interindividual ecological distances compared to viral contigs in a previously published cohort of 10 healthy individuals, while simultaneously improving longitudinal virome stability. Lastly, by reanalyzing a previously published metagenomics data set with >1,000 samples, we determined that PHFs are prevalent across individuals and can aid in the detection of inflammatory bowel disease-specific virome signatures. Overall, our analyses support the use of predicted phage hosts in reducing between-sample distances and providing a biologically relevant framework for making between-sample virome comparisons.

IMPORTANCE

The human gut virome consists mainly of bacteriophages (phages), which infect bacteria and show high individual specificity and variability, complicating cross-study comparisons. Furthermore, existing taxonomic frameworks offer limited insight into their interactions with bacterial hosts. In this study, we propose using predicted phage host families (PHFs) as a higher-level classification unit to enhance functional cross-study comparisons. We demonstrate that bioinformatic predictions of phage hosts align with Hi-C sequencing results at the host family level in human and mouse fecal samples. We further show that PHFs reduce ecological distances and improve virome stability over time. Additionally, reanalysis of a large metagenomics data set revealed that PHFs are widespread and can help identify disease-specific virome patterns, such as those linked to inflammatory bowel disease.

Microbial vitamin biosynthesis links gut microbiota dynamics to chemotherapy toxicity

Dose-limiting toxicities pose a major barrier to cancer treatment. While preclinical studies show that the gut microbiota influences and is influenced by anticancer drugs, data from patients paired with careful side effect monitoring remains limited. Here, we investigate capecitabine (CAP)-microbiome interactions through longitudinal metagenomic sequencing of stool from 56 advanced colorectal cancer patients. CAP significantly altered the gut microbiome, enriching for menaquinol (vitamin K2) biosynthesis genes. Transposon library screens, targeted gene deletions, and media supplementation revealed that menaquinol biosynthesis protects Escherichia coli from drug toxicity. Stool menaquinol gene and metabolite levels were associated with decreased peripheral sensory neuropathy. Machine learning models trained in this cohort predicted toxicities in an independent cohort. Taken together, these results suggest treatment-associated increases in microbial vitamin biosynthesis serve a chemoprotective role for bacterial and host cells. Further, our findings provide a foundation for in-depth mechanistic dissection, human intervention studies, and extension to other cancer treatments.IMPORTANCESide effects are common during the treatment of cancer. The trillions of microbes found within the human gut are sensitive to anticancer drugs, but the effects of treatment-induced shifts in gut microbes for side effects remain poorly understood. We profiled gut microbes in colorectal cancer patients treated with capecitabine and carefully monitored side effects. We observed a marked expansion in genes for producing vitamin K2 (menaquinone). Vitamin K2 rescued gut bacterial growth and was associated with decreased side effects in patients. We then used information about gut microbes to develop a predictive model of drug toxicity that was validated in an independent cohort. These results suggest that treatment-associated increases in bacterial vitamin production protect both bacteria and host cells from drug toxicity, providing new opportunities for intervention and motivating the need to better understand how dietary intake and bacterial production of micronutrients like vitamin K2 influence cancer treatment outcomes.

Patients with status epilepticus and new-onset refractory status epilepticus display drastically altered fecal microbiomes compared to chronic epilepsy patients

OBJECTIVE

New-onset refractory status epilepticus (NORSE) occurs in people without pre-existing epilepsy or a rapidly identified structural, toxic, metabolic, or other cause. NORSE is a rare disorder with high morbidity and mortality rates and limited evidence for effective therapies. We aimed to assess whether the gut microbiome of NORSE and status epilepticus (SE) differs from that of chronic epilepsy, whether NORSE differs from SE at different disease time points, and to examine the correlations between specific gut microbiota and cytokines in NORSE and SE.

METHODS

This longitudinal cohort study observed patients with NORSE (n = 15), SE (n = 17), and chronic epilepsy who were not in SE (n = 12). NORSE patients were recruited through the NORSE Consortium. Patients with NORSE and SE underwent longitudinal serial biospecimen collection. Fecal samples were subjected to whole-community shotgun metagenomics to characterize microbiome features. Cohorts were evaluated for prokaryotic, eukaryotic, and functional diversity. Correlations between blood inflammatory cytokine levels and microbiome features and covariate analysis with critical illness and clinical treatments were examined for NORSE and SE patients during and after SE resolution.

RESULTS

During SE, NORSE and SE patients had significantly different prokaryotic, eukaryotic, and functional microbiome levels compared to chronic epilepsy patients without SE. Limited microbiome differences were observed within and between NORSE and SE, although these groups displayed differing correlation patterns between microbial species and cytokines. Patients who later died or were tube-fed harbored significantly different microbiomes than those who survived or were orally fed.

SIGNIFICANCE

NORSE and SE patients present with a more variable and dramatically different fecal microbiome than chronic epilepsy patients, which may indicate gut dysbiosis that may be reciprocally linked to inflammatory responses. Although NORSE and SE patients had similar microbiome structures, fungal and bacterial correlates with inflammatory cytokines differed between NORSE and SE, with confounding factors influencing microbiome structure. Our data suggest a microbiome-specific response to NORSE and SE, with implications for future treatment strategies.

Effects of feeding a simulated waste milk on growth, health, fecal microbiota, and antibiotic resistance in dairy heifer calves

Feeding waste milk, a common practice in dairy farming, exposes calves to subtherapeutic levels of antimicrobials, potentially contributing to antibiotic resistance-a growing concern globally. Many dairy farmers, including those in Ireland, continue this practice, feeding waste milk from antibiotic-treated cows to calves. Although previous studies have linked waste milk feeding to changes in calf growth and health during the preweaning period, its effects postweaning remain unclear. This study examined how the duration of antimicrobial exposure at levels equivalent to those found in waste milk influences health and growth outcomes of dairy heifer calves both before and after weaning. It also assessed the prevalence of extended-spectrum β-lactamase (ESBL)-resistant Escherichia coli in feces and changes in the fecal microbiota over time. To mimic waste milk, as derived from a cow treated with an intramammary suspension of antibiotics, a simulated waste milk (SWM) was prepared by adding amoxicillin (1.68 mg/L) and neomycin (2.28 mg/L) to a conventional milk replacer (MR). The study employed a randomized block design with 87 dairy heifer calves assigned to 1 of 3 treatments: (1) long-term antibiotic (LTA), with calves fed SWM until weaning at 12 wk; (2) short-term antibiotic (STA), with SWM fed from 3 to 5 wk; and (3) control (CONT), with calves fed antibiotic-free MR. Calves were weighed weekly, and health scores, including fecal scores (tail and hindquarters cleanliness as diarrhea indicator), were recorded twice per week. Fecal and blood samples were collected to analyze microbiome changes and the shedding of antimicrobial resistance. Blood samples were taken to measure systemic inflammation, using serum amyloid A as a biomarker. Results indicated that SWM feeding did not affect average daily gains before or after weaning. However, higher fecal scores were observed in the LTA group during weaning and after weaning in the STA group. Antibiotic-resistant isolates were present in all groups, with the highest prevalence in LTA. Fecal microbiota analysis revealed treatment-specific microbial community variations, with increase of Enterococcus faecium genes resistant to macrolide, aminoglycoside, and tetracycline antibiotics in LTA and STA compared with CONT. In summary, SWM feeding did not significantly affect growth or overall health, but it was associated with increased fecal shedding of resistant bacteria and some changes in the microbiota, indicating potential long-term implications for antimicrobial resistance in dairy herds.

Microbes with higher metabolic independence are enriched in human gut microbiomes under stress

A wide variety of human diseases are associated with loss of microbial diversity in the human gut, inspiring a great interest in the diagnostic or therapeutic potential of the microbiota. However, the ecological forces that drive diversity reduction in disease states remain unclear, rendering it difficult to ascertain the role of the microbiota in disease emergence or severity. One hypothesis to explain this phenomenon is that microbial diversity is diminished as disease states select for microbial populations that are more fit to survive environmental stress caused by inflammation or other host factors. Here, we tested this hypothesis on a large scale, by developing a software framework to quantify the enrichment of microbial metabolisms in complex metagenomes as a function of microbial diversity. We applied this framework to over 400 gut metagenomes from individuals who are healthy or diagnosed with inflammatory bowel disease (IBD). We found that high metabolic independence (HMI) is a distinguishing characteristic of microbial communities associated with individuals diagnosed with IBD. A classifier we trained using the normalized copy numbers of 33 HMI-associated metabolic modules not only distinguished states of health vs IBD, but also tracked the recovery of the gut microbiome following antibiotic treatment, suggesting that HMI is a hallmark of microbial communities in stressed gut environments.

Lactobacillus Restructures the Micro/Mycobiome to Combat Inflammation-Mediated Right Ventricular Dysfunction in Pulmonary Arterial Hypertension

BACKGROUND

Inflammation suppresses right ventricular (RV) function in pulmonary arterial hypertension (PAH). In particular, we showed GP130 (glycoprotein-130) signaling promotes pathological microtubule remodeling and RV dysfunction in rodent PAH. Emerging data demonstrate the intestinal microbiome regulates systemic inflammation, but the impact of modulating the gut microbiome on the GP130-microtubule axis in RV failure is unknown.

METHODS

Two weeks following monocrotaline injection, rats were administered daily Lactobacillus rhamnosus (4×107 colony-forming units) via oral gavage for 10 days. Next-generation metagenomics and internal transcribed spacer 2 sequencing delineated fecal bacterial and fungal compositions. SomaScan proteomics measured levels of 7596 serum proteins. RV immunoblots quantified protein abundances. Light or super resolution confocal microscopy assessed RV, lung, and jejunal morphology. Echocardiography and invasive closed-chest pressure-volume loops evaluated PAH severity and RV function. The relationship between Lactobacillus abundance and RV function was assessed in 65 patients with PAH.

RESULTS

Lactobacillus administration restructured both the intestinal micro- and mycobiome. The alteration in the gut ecosystem improved intestinal health as demonstrated by increased jejunal villus length and glycocalyx thickness and diminished intestinal permeability biomarkers. Serum proteomics revealed Lactobacillus modulated systemic inflammation and decreased circulating GP130 ligands. Lactobacillus-mediated suppression of GP130 signaling blunted pathological microtubule remodeling in RV cardiomyocytes. Microtubule-associated phenotypes, including RV cardiomyocyte and nuclear hypertrophy, transverse tubule integrity, and connexin-43 localization, were all corrected with Lactobacillus. These cellular changes manifested as improved RV function despite no significant alteration in PAH severity. Finally, patients with PAH and detectable fecal Lactobacillus had superior RV function despite similar mean pulmonary arterial pressure and pulmonary vascular resistance as compared with those without detectable Lactobacillus.

CONCLUSIONS

Lactobacillus supplementation restructures the gut micro/mycobiome, restores intestinal health, dampens systemic inflammation, and reduces GP130 ligands and associated RV cardiomyocyte microtubule remodeling. These data identify a novel microbiome-inflammation-microtubule axis that has therapeutic relevance for RV dysfunction.

Prognostic Value of a Multivariate Gut Microbiome Model for Progression from Normal Cognition to Mild Cognitive Impairment Within 4 Years

Little is known about the dysbiosis of the gut microbiome in patients with mild cognitive impairment (MCI) potentially at risk for the development of Alzheimer's disease (AD). So far, only cross-sectional differences and not longitudinal changes and their prognostic significance have been in the scope of research in MCI. Therefore, we investigated the ability of longitudinal taxonomic and functional gut microbiome data from 100 healthy controls (HC) to predict the progression from normal cognition to MCI over a 4-year follow-up period (4yFU). Logistic regression models were built with baseline features that best discriminated between the two groups using an ANOVA-type statistical analysis. The best model for the discrimination of MCI converters was based on functional data using Gene Ontology (GO), which included 14 features. This model achieved an area under the receiver operating characteristic curve (AUROC) of 0.84 at baseline, 0.78 at the 1-year follow-up (1yFU), and 0.75 at 4yFU. This functional model outperformed the taxonomic model, which included 38 genera features, in terms of descriptive performance and showed comparable efficacy to combined analyses integrating functional, taxonomic, and clinical characteristics. Thus, gut microbiome algorithms have the potential to predict MCI conversion in HCs over a 4-year period, offering a promising innovative supplement for early AD identification.

Microplastics reduced the natural attenuation of antibiotic resistance genes in fertilized soils

The prolonged application of mulch and manure in agriculture has led to significant microplastic (MP) pollution in fertilized soils, raising global concerns about its potential impacts on soil health and ecosystem function. However, the effects of MP exposure on antibiotic resistance genes (ARGs) and microbial communities in fertilized soils are unknown. Therefore, we comprehensively explored the trends and drivers of ARGs during their natural abatement under the stress of conventional and biodegradable MP addition in fertilized soils using a soil microcosm experiment and metagenomic. The findings indicated that the presence of polybutylene succinate MPs (PBS-MPs) reduced the natural attenuation rate of ARGs in fertilized soils while increasing the fraction of high-risk ARGs in soils. Microbial communities and mobile genetic elements (MGEs) mainly drove the inhibitory effect of MPs on ARG abatement. Interestingly, most potential hosts for the coexistence of ARGs, metal resistance genes (MRGs), and MGEs were annotated as pathogens, such as Escherichia spp., Salmonella spp., and Klebsiella spp. In addition, MP stress in fertilized soil may lead to long-term contamination by highly virulent and antibiotic-resistant Escherichia coli. MPs influence the distribution of carbon sources, which in turn reduces the diversity and stability of soil microbial communities, while simultaneously promoting the colonization of crucial ARG hosts, like Dyella spp. This ultimately prolonged the high-risk state for ARG proliferation in the soil. This study highlights the significant risk posed by MPs to the persistence and spread of ARGs in fertilized soils. These results provide valuable insights for managing MP contamination in agricultural systems, emphasizing the need for sustainable practices to mitigate the long-term environmental risks associated with MP pollution.

Intestinal microbiota profiles of captive-bred cynomolgus macaques reveal influence of biogeography and age

BACKGROUND

Age-associated changes to the intestinal microbiome may be linked to inflammageing and the development of age-related chronic diseases. Cynomolgus macaques, a common animal model in biomedical research, have strong genetic physiological similarities to humans and may serve as beneficial models for the effect of age on the human microbiome. However, age-associated changes to their intestinal microbiome have previously only been investigated in faecal samples. Here, we have characterised and investigated the effects of age in the cynomolgus macaque intestinal tract in luminal samples from both the small and large intestine.

RESULTS

Whole metagenomic shotgun sequencing was used to analyse the microbial communities in intestinal content obtained from six different intestinal regions, covering the duodenum to distal colon, of 24 healthy, captive-bred cynomolgus macaques, ranging in age from 4 to 20 years. Both reference-based and assembly-based computational profiling approaches were used to analyse changes to intestinal microbiota composition and metabolic potential associated with intestinal biogeography and age. Reference-based computational profiling revealed a significant and progressive increase in both species richness and evenness along the intestinal tract. The microbial community composition also significantly differed between the small intestine, caecum, and colon. Notably, no significant changes in the taxonomic abundance of individual taxa with age were found except when sex was included as a covariate. Additionally, using an assembly-based computational profiling approach, 156 putative novel bacterial and archaeal species were identified.

CONCLUSIONS

We observed limited effects of age on the composition of the luminal microbiota in the profiled regions of the intestinal tract except when sex was included as a covariate. The enteric microbial communities of the small and the large intestine were, however, distinct, highlighting the limitations of frequently used faecal microbial profiling as a proxy for the intestinal microbiota. The identification of a number of putative novel microbial taxa contributes to knowledge of the full diversity of the cynomolgus macaque intestinal microbiome.

Acute exposure to high-fat diet impairs ILC3 functions and gut homeostasis

Prolonged exposure to a high-fat diet (HFD) exacerbates intestinal disease pathology, yet the early events preceding the development of gut inflammation remain poorly understood. Here, we show that within 48 h, HFD impairs intestinal group 3 innate lymphoid cells (ILC3s) and their capacity to produce interleukin-22 (IL-22), critical for maintaining gut homeostasis. This loss of function was associated with rapid dysbiosis, increased gut permeability, and reduced production of antimicrobial peptides, mucus, and tight-junction proteins. While saturated fatty acids metabolized through oxidation impaired ILC3 function, unsaturated fatty acids sustained IL-22 secretion by ILC3s through the formation of lipid droplets using diacylglycerol O-acyltransferase (DGAT) enzymes. Upon inflammation, saturated fatty acids impaired IL-22 production by ILC3s and increased the susceptibility of the gut to injury. Our findings reveal the differential acute impact of saturated and unsaturated fatty acids on gut homeostasis through distinct metabolic pathways in ILC3s.

Nivolumab plus low-dose ipilimumab in hypermutated HER2-negative metastatic breast cancer: a phase II trial (NIMBUS)

In the phase II NIMBUS trial, patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) and high tumor mutational burden (TMB ≥ 9 mut/Mb) received nivolumab (3 mg/kg biweekly) and low-dose ipilimumab (1 mg/kg every 6 weeks) for 2 years or until progression. The primary endpoint was objective response rate (ORR) per RECIST 1.1 criteria. Among 30 patients enrolled, the median TMB was 10.9 mut/Mb (range: 9-110) and the confirmed objective response rate was 20%. Secondary endpoints included progression-free survival, overall survival, clinical benefit rate, and safety and tolerability, including immune-related adverse events (irAEs). A prespecified correlative outcome was to evaluate the ORR in patients with a TMB ≥ 14 mut/Mb. Patients with TMB ≥ 14 mut/Mb (n = 6) experienced higher response rates (60% vs 12%; p = 0.041) and showed a trend towards improved progression-free survival and overall survival compared to patients with TMB < 14 mut/Mb. Exploratory genomic analyses suggested that ESR1 and PTEN mutations may be associated with poor response, while clinical benefit was associated with a decrease or no change in tumor fraction by serial circulating tumor DNA during treatment. Stool microbiome analysis revealed that baseline blood TMB, PD-L1 positivity, and immune-related diarrhea are associated with distinct taxonomic profiles. In summary, some patients with hypermutated HER2-negative MBC experience extended clinical benefit with a dual immunotherapy regimen; a higher TMB, and additional genomic and microbiome biomarkers may optimize patient selection for therapy with nivolumab plus low-dose ipilimumab. (Funded by Bristol Myers Squibb; ClinicalTrials.gov identifier, NCT03789110).

Nicotinamide modulates gut microbial metabolic potential and accelerates recovery in mild-to-moderate COVID-19

Cellular NAD+ depletion, altered tryptophan metabolism and gut microbiome dysbiosis are associated with disease progression and unfavourable clinical outcomes in COVID-19. Here, we show that supplementing tryptophan metabolism with nicotinamide alleviates COVID-19 symptoms. We evaluate a 4-week intervention with a novel nicotinamide formulation (1,000 mg) in a prospective, double-blind, randomized, placebo-controlled trial in 900 symptomatic outpatients with PCR-proven COVID-19. In the primary analysis population of participants at risk for severe COVID-19, 57.6% of those receiving nicotinamide and 42.6% receiving placebo recover from their performance drop at week 2 (P = 0.004). Nicotinamide is also beneficial for returning to normal activities (P = 0.009). Effects on gut metagenomic signatures parallel clinical efficacy, suggesting that nicotinamide influences COVID-19-associated faecal microbiome changes. After 6 months, responders to nicotinamide in acute COVID-19 show fewer post-COVID symptoms than placebo responders (P = 0.010). No relevant safety signals are observed. Overall, our results show that nicotinamide leads to faster recovery of physical performance and modulates COVID-19-associated faecal microbiome changes.

Controlling Lampenflora in Heritage Sites: In Situ Testing of Polyoxometalate-Ionic Liquids in the Pommery Champagne Cellar

Artificial lighting, essential for geotouristic purposes in subterranean sites, has facilitated the growth of colored photosynthetic organisms (lampenflora) on monumental 19th century bas-reliefs of the Pommery Champagne cellar-a UNESCO-protected heritage site-causing significant aesthetic and physical deterioration. To sustainably preserve these stone artworks, biocidal polyoxometalate-ionic liquids (POM-ILs) are tested alongside the commercial biocide Preventol RI80 on three trial zones: cleaned and colonized areas of a wall and clean stone samples positioned on a testing station within the cellar. After 1 year, untreated control areas exhibit growth/regrowth of biofilms, whereas surfaces treated with POM-ILs or Preventol RI80 remain biofilm free. Measurements of colorimetry and chlorophyll fluorescence confirm the effectiveness of both biocides in controlling photosynthetic micro-organisms. However, confocal fluorescence microscopy highlights a reduced long-term inhibition by Preventol RI80 compared to POM-ILs, despite the latter being applied at lower concentrations. Metagenomic analysis further validates the performance of POM-ILs, showing a notable decrease in microbial richness and diversity in treated areas. While both products effectively inhibit phototrophs and fungi, their efficacy against Pseudomonadota is limited, likely due to microbial adaptation via antibiotic resistance genes. This study underscores the potential of POM-ILs as a sustainable alternative for preserving cultural heritage against microbial colonization.

Prolonged effect of antibiotic therapy on the gut microbiota composition, functionality, and antibiotic resistance genes' profiles in healthy stool donors

Introduction

Fecal microbiota transplantation (FMT) is highly effective in preventing Clostridioides difficile recurrence by restoring gut microbiota composition and function. However, the impact of recent antibiotic use, a key exclusion criterion for stool donors, on gut microbiota recovery is poorly understood.

Methods

We investigated microbial recovery dynamics following antibiotic use in three long-term stool donors from Canada and Finland. Using longitudinal stool sampling, metagenomic sequencing, and qPCR, we assessed changes in bacterial diversity, community composition, microbial functions, the gut phageome, and the risk of transmitting antibiotic-resistant genes (ARGs).

Results

Antibiotics caused lasting disruption to bacterial communities, significantly reducing important taxa like Bifidobacterium bifidum, Blautia wexlerae, Akkermansia muciniphila, Eubacterium sp. CAG 180, and Eubacterium hallii, with effects persisting for months. Functional analyses revealed alterations in housekeeping genes critical for energy production and biosynthesis, with no direct links to key health-related pathways. Antibiotics also disrupted viral populations, decreasing diversity and increasing crAssphage abundance, reflecting disrupted host-bacteriophage dynamics. No significant increase in clinically important ARGs was detected.

Discussion

These findings highlight the unpredictable and complex recovery of gut microbiota post-antibiotics. Individualized suspension periods in donor programs, guided by metagenomic analyses, are recommended to optimize FMT outcomes in various indications by considering antibiotic spectrum, duration, and host-specific factors.

Gut microbiome and blood biomarkers reveal differential responses to aerobic and anaerobic exercise in collegiate men of diverse training backgrounds

The gut microbiome influences physiological responses to exercise by modulating inflammatory markers and metabolite production. Athletes typically exhibit greater microbial diversity, which may be associated with improved performance, but the mechanisms linking different exercise modalities to the gut microbiome are not fully understood. In this study, blood and stool samples were collected from endurance athletes, strength athletes, and non-athletic controls performing two maximal exercise tests (the anaerobic Wingate test and the aerobic Bruce Treadmill Test) to integrate serum biomarker data with gut bacterial metagenomic profiles. While most biochemical markers showed similar post-exercise trends across groups, SPARC (secreted protein acidic and rich in cysteine) and adiponectin levels showed modality-specific responses. Strength-trained participants showed unique microbiome-biomarker associations after the Wingate test. In addition, baseline enrichment of certain bacterial taxa, including Clostridium phoceensis and Catenibacterium spp., correlated with reduced Bruce Treadmill test response in strength-trained individuals. These findings, while requiring further validation, indicate the complex interplay between exercise type, training background, and the gut microbiome, and suggest that specific microbial species may help shape recovery and adaptation.

Transmission of the human respiratory microbiome and antibiotic resistance genes in healthy populations

BACKGROUND

The human microbiome is transmissible between individuals, including pathogens and commensals with metabolic and immune-modulating effects, which could influence susceptibility, severity, and outcomes of both infection and non-infection diseases. However, limited studies of respiratory microbiome transmission within populations have been conducted. Herein, we performed species- and strain-level metagenomic analyses on oropharyngeal (OP) swabs from 1046 healthy urban dwellers across 13 districts, including 111 households with at least two cohabitants, to elucidate the transmission dynamics of the respiratory microbiome within households and communities.

RESULTS

We found that geographic districts accounted for the greatest variation in the OP microbiome, with unrelated individuals from the same district showing greater microbiome similarity and higher strain-sharing rates than those from different districts. Cohabitants, especially spouses and siblings, exhibited similar microbial abundances and shared more strains, with 16.7% (IQR 0.0-33.3%) of strains shared among cohabitants, compared to 0.0% (IQR 0.0-11.1%) in non-cohabiting pairs (p < 0.05). Both respiratory commensals and opportunistic pathogens were shared among cohabitants. In contrast, no evidence of vertical transmission was detected between mother-offspring pairs. Additionally, the OP microbiome contained diverse antibiotic resistance genes (ARGs), with 15.0% linked to mobile genetic elements (MGEs) or plasmids; the flanking sequences of these ARGs were more conserved across species than those of non-MGE-associated ARGs, suggesting horizontal transfer of ARGs among respiratory microorganisms.

CONCLUSIONS

In summary, we characterized the transmissible nature of the OP microbiome and the risk of ARG dissemination among respiratory microorganisms. These findings underscore the role of respiratory microbes and ARGs exchange in shaping the microbiome of healthy populations and emphasize their relevance to public health strategies for respiratory health management. Video Abstract.

Synergistic role of gut-microbial L-ornithine in enhancing ustekinumab efficacy for Crohn's disease

The role of the intestinal microbiome in Crohn's disease (CD) treatment remains poorly understood. This study investigates microbe-host interactions in CD patients undergoing ustekinumab (UST) therapy. Fecal metagenome, metabolome, and host transcriptome data from 85 CD patients were analyzed using multi-omics integration and mediation analysis. Our findings reveal significant microbiome-metabolite-host interactions. Specifically, Faecalibacterium prausnitzii was linked to altered L-ornithine biosynthesis, resulting in higher L-ornithine levels in patients before UST therapy. In vivo and in vitro studies demonstrated that microbiome-derived L-ornithine enhances UST treatment sensitivity in CD by disrupting the host IL-23 receptor signaling and inhibiting Th17 cell stabilization through the IL-12RB1/TYK2/STAT3 axis. L-ornithine significantly enhances the therapeutic efficacy of UST in CD patients, as demonstrated in a prospective clinical trial. These findings suggest that targeting specific microbe-host metabolic pathways may improve the efficacy of inflammatory bowel disease (IBD) treatments.

Selective butyrate production from CO2 and methanol in microbial electrosynthesis - influence of pH

Methanol assisted microbial electrosynthesis (MES) enables butyrate production from carbon dioxide and methanol using external electricity. However, the effects of operational parameters on butyrate formation remain unclear. By running three flat plate MES reactors with fed-batch mode at three controlled pH values (5.5, 6 and 7), the present study investigated the influence of pH on methanol assisted MES by comparing the process performance, microbial community structure, and genetic potential. The highest butyrate selectivity (87 % on carbon basis) and the highest butyrate production rate of 0.3 g L-1 d-1 were obtained at pH 6. At pH 7, a comparable butyrate production rate was achieved, yet with a lower selectivity (70 %) accompanied with acetate production. Butyrate production rate was considerably hindered at pH 5.5, reaching 0.1 g L-1 d-1, while the selectivity reached was up to 81 %. Methanol and CO2 consumption increased with pH, along with more negative cathodic potential and more negative redox potential. Furthermore, pH affected the thermodynamical feasibility of involved reactions. The results of metagenomic analyses suggest that Eubacterium callanderi dominated the microbial communities at all pH values, which was responsible for methanol and CO2 assimilation via the Wood-Ljungdahl pathway and was likely the main butyrate producer via the reverse β-oxidation pathway.

Accurate estimation of intraspecific microbial gene content variation in metagenomic data with MIDAS v3 and StrainPGC

Metagenomics has greatly expanded our understanding of the human gut microbiome by revealing a vast diversity of bacterial species within and across individuals. Even within a single species, different strains can have highly divergent gene content, affecting traits such as antibiotic resistance, metabolism, and virulence. Methods that harness metagenomic data to resolve strain-level differences in functional potential are crucial for understanding the causes and consequences of this intraspecific diversity. The enormous size of pangenome references, strain mixing within samples, and inconsistent sequencing depth present challenges for existing tools that analyze samples one at a time. To address this gap, we updated the MIDAS pangenome profiler, now released as version 3, and developed StrainPGC, an approach to strain-specific gene content estimation that combines strain tracking and correlations across multiple samples. We validate our integrated analysis using a complex synthetic community of strains from the human gut and find that StrainPGC outperforms existing approaches. Analyzing a large, publicly available metagenome collection from inflammatory bowel disease patients and healthy controls, we catalog the functional repertoires of thousands of strains across hundreds of species, capturing extensive diversity missing from reference databases. Finally, we apply StrainPGC to metagenomes from a clinical trial of fecal microbiota transplantation for the treatment of ulcerative colitis. We identify two Escherichia coli strains, from two different donors, that are both frequently transmitted to patients but have notable differences in functional potential. StrainPGC and MIDAS v3 together enable precise, intraspecific pangenomic investigations using large collections of metagenomic data without microbial isolation or de novo assembly.

Integrating metagenomics and metabolomics to study the gut microbiome and host relationships in sports across different energy systems

The gut microbiome plays a critical role in modulating host metabolism, influencing energy production, nutrient utilization, and overall physiological adaptation. In athletes, these microbial functions may be further specialized to meet the unique metabolic demands of different sports disciplines. This study explored the role of the gut microbiome in modulating host metabolism among Colombian athletes by comparing elite weightlifters (n = 16) and cyclists (n = 13) through integrative omics analysis. Fecal and plasma samples collected one month before an international event underwent metagenomic, metabolomic, and lipidomic profiling. Metagenomic analysis revealed significant microbial pathways, including L-arginine biosynthesis III and fatty acid biosynthesis initiation. Key metabolic pathways, such as phenylalanine, tyrosine, and tryptophan biosynthesis; arginine biosynthesis; and folate biosynthesis, were enriched in both athlete groups. Plasma metabolomics and lipidomics revealed distinct metabolic profiles and a separation between athlete types through multivariate models, with lipid-related pathways such as lipid droplet formation and glycolipid synthesis driving the differences. Notably, elevated carnitine, amino acid, and glycerolipid levels in weightlifters suggest energy system-specific metabolic adaptations. These findings underscore the complex relationship between the gut microbiota composition and metabolic responses tailored to athletic demands, laying the groundwork for personalized strategies to optimize performance. This research highlights the potential for targeted modulation of the gut microbiota as a basis for tailored interventions to support specific energy demands in athletic disciplines.

mKmer: an unbiased K-mer embedding of microbiomic single-microbe RNA sequencing data

The advanced single-microbe RNA sequencing (smRNA-seq) technique addresses the pressing need to understand the complexity and diversity of microbial communities, as well as the distinct microbial states defined by different gene expression profiles. Current analyses of smRNA-seq data heavily rely on the integrity of reference genomes within the queried microbiota. However, establishing a comprehensive collection of microbial reference genomes or gene sets remains a significant challenge for most real-world microbial ecosystems. Here, we developed an unbiased embedding algorithm utilizing K-mer signatures, named mKmer, which bypasses gene or genome alignment to enable species identification for individual microbes and downstream functional enrichment analysis. By substituting gene features in the canonical cell-by-gene matrix with highly conserved K-mers, we demonstrate that mKmer outperforms gene-based methods in clustering and motif inference tasks using benchmark datasets from crop soil and human gut microbiomes. Our method provides a reference genome-free analytical framework for advancing smRNA-seq studies.

Strain tracking in complex microbiomes using synteny analysis reveals per-species modes of evolution

Microbial species diversify into strains through single-nucleotide mutations and structural changes, such as recombination, insertions and deletions. Most strain-comparison methods quantify differences in single-nucleotide polymorphisms (SNPs) and are insensitive to structural changes. However, recombination is an important driver of phenotypic diversification in many species, including human pathogens. We introduce SynTracker, a tool that compares microbial strains using genome synteny-the order of sequence blocks in homologous genomic regions-in pairs of metagenomic assemblies or genomes. Genome synteny is a rich source of genomic information untapped by current strain-comparison tools. SynTracker has low sensitivity to SNPs, has no database requirement and is robust to sequencing errors. It outperforms existing tools when tracking strains in metagenomic data and is particularly suited for phages, plasmids and other low-data contexts. Applied to single-species datasets and human gut metagenomes, SynTracker, combined with an SNP-based tool, detects strains enriched in either point mutations or structural changes, providing insights into microbial evolution in situ.

Gut metagenomes reveal interactions between dietary restriction, ageing and the microbiome in genetically diverse mice

The gut microbiome changes with age and has been proposed to mediate the benefit of lifespan-extending interventions such as dietary restriction. However, the causes and consequences of microbiome ageing and the potential of such interventions remain unclear. Here we analysed 2,997 metagenomes collected longitudinally from 913 deeply phenotyped, genetically diverse mice to investigate interactions between the microbiome, ageing, dietary restriction (caloric restriction and fasting), host genetics and a range of health parameters. Among the numerous age-associated microbiome changes that we find in this cohort, increased microbiome uniqueness is the most consistent parameter across a second longitudinal mouse experiment that we performed on inbred mice and a compendium of 4,101 human metagenomes. Furthermore, cohousing experiments show that age-associated microbiome changes may be caused by an accumulation of stochastic environmental exposures (neutral theory) rather than by the influence of an ageing host (selection theory). Unexpectedly, the majority of taxonomic and functional microbiome features show small but significant heritability, and the amount of variation explained by host genetics is similar to ageing and dietary restriction. We also find that more intense dietary interventions lead to larger microbiome changes and that dietary restriction does not rejuvenate the microbiome. Lastly, we find that the microbiome is associated with multiple health parameters, including body composition, immune components and frailty, but not lifespan. Overall, this study sheds light on the factors influencing microbiome ageing and aspects of host physiology modulated by the microbiome.

A shotgun metagenomic study identified short-chain fatty acid-producing species and their functions in the gut microbiome of adults with depressive symptoms: Large-scale shotgun sequencing data of the gut microbiota using a cross-sectional design

BACKGROUND

The gut-brain axis is emerging as a novel mechanism to explain depressive disorders.

METHODS

We performed shotgun metagenomic sequencing of stool samples obtained from 133 individuals with depression and 532 without depression. This study examined the taxonomy, functional pathways, and predicted metabolites profiles associated with depressive symptoms, using generalized linear models. To explore links between the taxonomic and functional pathway results, we compared the relative abundance of specific species contributing to pathways significantly associated with depressive symptoms.

RESULTS

Taxonomic composition suggested a disruption in short-chain fatty acid (SCFA)-producing capacity of the gut microbiome in the depressed group. Pathways related to SCFA biosynthesis were also depleted in this group. Faecalibacterium prausnitzii, a well-known SCFA-producing bacterium, was significantly decreased in the depressed group and was identified as a major contributor to the depleted pathways. When inferring the metabolites related to depression from metagenomic data, higher levels of docosapentaenoic acid, stearoyl ethanolamide, putrescine, and bilirubin were more likely to be found in the depressed group.

CONCLUSION

The present findings highlight the altered gut microbiota and associated SCFA-related pathways in individuals with depression. The depletion of F. prausnitzii and its contribution to SCFA production suggest that it is a potential therapeutic target for depression.

The food additive butylated hydroxyanisole minimally affects the human gut microbiome ex vivo

Butylated hydroxyanisole (BHA) continues to raise consumer concerns. All previous evaluations of this additive have failed to consider its effect on the gut microbiome, even though it enters the colon. An ex vivo model was used to assess the effect of BHA on microbial communities from 24 donors, aged infants to older adults. A dose of 0.35 g/L BHA elicited no statistically significant changes in the functional outputs or community structure for any age group. Although not large enough to affect community diversity, there were some significant decreases at the phylum level. Among the genes most significantly affected by treatment with BHA across age groups are those involved in lipopolysaccharide synthesis and bacterial electron transport encoded by Bacteroidota, Proteobacteria, and Verrucomicrobiota. Given what is known about the intracellular activity of BHA, these genes may hint at a mechanism behind BHA's evident, but minimally detrimental effect on the gut microbiota.

Fecal microbiota transplantation against moderate-to-severe atopic dermatitis: A randomized, double-blind controlled explorer trial

BACKGROUND

Fecal microbiota transplantation (FMT) is a novel treatment for inflammatory diseases. Herein, we assess its safety, efficacy, and immunological impact in patients with moderate-to-severe atopic dermatitis (AD).

METHODS

In this randomized, double-blind, placebo-controlled clinical trial, we performed the efficacy and safety assessment of FMT for moderate-to-severe adult patients with AD. All patients received FMT or placebo once a week for 3 weeks, in addition to their standard background treatments. Patients underwent disease severity assessments at weeks 0, 1, 2, 4, 8, 12, and 16, and blood and fecal samples were collected for immunologic analysis and metagenomic shotgun sequencing, respectively. Safety was monitored throughout the trial.

RESULTS

Improvements in eczema area and severity index (EASI) scores and percentage of patients achieving EASI 50 (50% reduction in EASI score) were greater in patients treated with FMT than in placebo-treated patients. No serious adverse reactions occurred during the trial. FMT treatment decreased the Th2 and Th17 cell proportions among the peripheral blood mononuclear cells, and the levels of TNF-α, and total IgE in serum. By contrast, the expression levels of IL-12p70 and perforin on NK cells were increased. Moreover, FMT altered the abundance of species and functional pathways of the gut microbiota in the patients, especially the abundance of Megamonas funiformis and the pathway for 1,4-dihydroxy-6-naphthoate biosynthesis II.

CONCLUSION

FMT was a safe and effective therapy in moderate-to-severe adult patients with AD; the treatment changed the gut microbiota compositions and functions.

Distinct gut microbiome characteristics and dynamics in patients with Parkinson's disease based on the presence of premotor rapid-eye movement sleep behavior disorders

BACKGROUND

Alpha-synuclein aggregation, a hallmark of Parkinson's disease (PD), is hypothesized to often begin in the enteric or peripheral nervous system in "body-first" PD and progresses through the vagus nerve to the brain, therefore REM sleep behavior disorder (RBD) precedes the PD diagnosis. In contrast, "brain-first" PD begins in the central nervous system. Evidence that gut microbiome imbalances observed in PD and idiopathic RBD exhibit similar trends supports body-first and brain-first hypothesis and highlights the role of microbiota in PD pathogenesis. However, further investigation is needed to understand distinct microbiome changes in body-first versus brain-first PD over the disease progression.

RESULTS

Our investigation involved 104 patients with PD and 85 of their spouses as healthy controls (HC), with 57 patients (54.8%) categorized as PD-RBD(+) and 47 patients (45.2%) as PD-RBD(-) based on RBD presence before the PD diagnosis. We evaluated the microbiome differences between these groups over the disease progression through taxonomic and functional differential abundance analyses and carbohydrate-active enzyme (CAZyme) profiles based on metagenome-assembled genomes. The PD-RBD(+) gut microbiome showed a relatively stable microbiome composition irrespective of disease stage. In contrast, PD-RBD(-) microbiome exhibited a relatively dynamic microbiome change as the disease progressed. In early-stage PD-RBD(+), Escherichia and Akkermansia, associated with pathogenic biofilm formation and host mucin degradation, respectively, were enriched, which was supported by functional analysis. We discovered that genes of the UDP-GlcNAc synthesis/recycling pathway negatively correlated with biofilm formation; this finding was further validated in a separate cohort. Furthermore, fiber intake-associated taxa were decreased in early-stage PD-RBD(+) and the biased mucin-degrading capacity of CAZyme compared to fiber degradation.

CONCLUSION

We determined that the gut microbiome dynamics in patients with PD according to the disease progression depend on the presence of premotor RBD. Notably, early-stage PD-RBD(+) demonstrated distinct gut microbial characteristics, potentially contributing to exacerbation of PD pathophysiology. This outcome may contribute to the development of new therapeutic strategies targeting the gut microbiome in PD. Video Abstract.

Uncovering microbial interactions in a persistent Planktothrix bloom: Towards early biomarker identification in hypereutrophic lakes

Cyanobacterial harmful algal blooms pose significant threats to global water supplies, ecosystems, and economies. Among the harmful cyanobacteria, Planktothrix, a resilient and toxin-producing filamentous cyanobacterium, has garnered increasing attention. However, an understanding of the entire microbiome, particularly the phycosphere surrounding Planktothrix blooms, remains largely unexplored. To the best of our knowledge, this is the first comprehensive study combining 16S rDNA and fungal internal transcribed spacer amplicon sequencing and shotgun metagenomics to elucidate Planktothrix bloom microbiomes and identify potential microbial or functional biomarkers for CyanoHABs. Our observations revealed that a summer bloom in Grand Lake St. Marys was initiated with Dolichospermum and then shifted to Planktothrix dominance. This transition was associated with nitrogen metabolism genes, suggesting that nitrogen plays a key role in bloom persistence through interactions among nitrogen-fixing bacteria, ammonia-oxidizing archaea, anammox bacteria, and denitrifiers. Additionally, metagenomic data revealed a strong positive correlation of toxin concentration with carbohydrate-nitrogen-sulfur-fatty acid associated metabolic pathways and a strong negative correlation with pollutant degradation pathways. Intriguingly, diazotrophic methane-related microbes were detected, which opens discussion on potential symbiosis that couples nitrogen and carbon metabolism. Toxin-degrading bacteria, such as Polynucleobacter and Acidovorax, were positively correlated with fungi like Vishniacozyma, proposing their cooperative roles during bloom events. Notably, Rhodobacter, a photosynthetic purple non-sulfur bacterium, showed strong negative correlations with both Planktothrix and the toxin-producing gene mcyE, positioning it as a promising biomarker for early bloom detection. Overall, this study advances the understanding of Planktothrix-dominated bloom ecology and highlights microbial signatures for proactive CyanoHAB management in freshwater systems.

Improved overall survival in an anti-PD-L1 treated cohort of newly diagnosed glioblastoma patients is associated with distinct immune, mutation, and gut microbiome features: a single arm prospective phase I/II trial

This phase I/II trial aims to evaluate the efficacy of concurrent atezolizumab with radiation therapy and temozolomide (TMZ) followed by adjuvant atezolizumab and TMZ in newly diagnosed glioblastoma (GBM) patients and to identify pre-treatment correlates with outcome (N = 60). Trial number: NCT03174197. The primary outcome was overall survival (OS) whereas secondary outcomes were retrospective global-omics analyses to identify pre-treatment immune and genetic tumor features that correlated with survival. Concurrent use of atezolizumab with radiation and TMZ demonstrated OS in line with published trials for newly diagnosed GBM. Tumor genomic (WES and/or targeted NGS panel), transcriptomic (RNAseq) and tissue microenvironment imaging, as well as fecal metagenomic sequencing were conducted. Gene set enrichment analysis of tumors identified multiple immune-based transcriptomic programs to distinguish patients with longer versus shorter survival (p ≤ 0.01). GBM immune enrichment was highly associated with the pre-treatment tumor mesenchymal subtype and patient gastrointestinal bacterial taxa profile.