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Bioinformatics (Oxford, England) Jun 2024Shotgun metagenomics allows for direct analysis of microbial community genetics, but scalable computational methods for the recovery of bacterial strain genomes from...
SUMMARY
Shotgun metagenomics allows for direct analysis of microbial community genetics, but scalable computational methods for the recovery of bacterial strain genomes from microbiomes remains a key challenge. We introduce Floria, a novel method designed for rapid and accurate recovery of strain haplotypes from short and long-read metagenome sequencing data, based on minimum error correction (MEC) read clustering and a strain-preserving network flow model. Floria can function as a standalone haplotyping method, outputting alleles and reads that co-occur on the same strain, as well as an end-to-end read-to-assembly pipeline (Floria-PL) for strain-level assembly. Benchmarking evaluations on synthetic metagenomes show that Floria is > 3× faster and recovers 21% more strain content than base-level assembly methods (Strainberry) while being over an order of magnitude faster when only phasing is required. Applying Floria to a set of 109 deeply sequenced nanopore metagenomes took <20 min on average per sample and identified several species that have consistent strain heterogeneity. Applying Floria's short-read haplotyping to a longitudinal gut metagenomics dataset revealed a dynamic multi-strain Anaerostipes hadrus community with frequent strain loss and emergence events over 636 days. With Floria, accurate haplotyping of metagenomic datasets takes mere minutes on standard workstations, paving the way for extensive strain-level metagenomic analyses.
AVAILABILITY AND IMPLEMENTATION
Floria is available at https://github.com/bluenote-1577/floria, and the Floria-PL pipeline is available at https://github.com/jsgounot/Floria_analysis_workflow along with code for reproducing the benchmarks.
Topics: Metagenome; Metagenomics; Haplotypes; Software; Humans; Genome, Bacterial; Microbiota; Bacteria; High-Throughput Nucleotide Sequencing; Sequence Analysis, DNA
PubMed: 38940183
DOI: 10.1093/bioinformatics/btae252 -
Bioinformatics (Oxford, England) Jun 2024The study of bacterial genome dynamics is vital for understanding the mechanisms underlying microbial adaptation, growth, and their impact on host phenotype. Structural...
MOTIVATION
The study of bacterial genome dynamics is vital for understanding the mechanisms underlying microbial adaptation, growth, and their impact on host phenotype. Structural variants (SVs), genomic alterations of 50 base pairs or more, play a pivotal role in driving evolutionary processes and maintaining genomic heterogeneity within bacterial populations. While SV detection in isolate genomes is relatively straightforward, metagenomes present broader challenges due to the absence of clear reference genomes and the presence of mixed strains. In response, our proposed method rhea, forgoes reference genomes and metagenome-assembled genomes (MAGs) by encompassing all metagenomic samples in a series (time or other metric) into a single co-assembly graph. The log fold change in graph coverage between successive samples is then calculated to call SVs that are thriving or declining.
RESULTS
We show rhea to outperform existing methods for SV and horizontal gene transfer (HGT) detection in two simulated mock metagenomes, particularly as the simulated reads diverge from reference genomes and an increase in strain diversity is incorporated. We additionally demonstrate use cases for rhea on series metagenomic data of environmental and fermented food microbiomes to detect specific sequence alterations between successive time and temperature samples, suggesting host advantage. Our approach leverages previous work in assembly graph structural and coverage patterns to provide versatility in studying SVs across diverse and poorly characterized microbial communities for more comprehensive insights into microbial gene flux.
AVAILABILITY AND IMPLEMENTATION
rhea is open source and available at: https://github.com/treangenlab/rhea.
Topics: Microbiota; Metagenome; Genome, Bacterial; Metagenomics; Gene Transfer, Horizontal; Bacteria; Algorithms
PubMed: 38940156
DOI: 10.1093/bioinformatics/btae224 -
Frontiers in Bioscience (Landmark... Jun 2024Mitochondrial DNA (mtDNA) is located in the mitochondrial matrix, in close proximity to major sources of reactive oxygen species (ROS) in the cell. This makes mtDNA one... (Review)
Review
Mitochondrial DNA (mtDNA) is located in the mitochondrial matrix, in close proximity to major sources of reactive oxygen species (ROS) in the cell. This makes mtDNA one of the most susceptible components to damage in the cell. The nuclear factor E2-related factor 2/antioxidant response element (Nrf2/ARE) signaling pathway is an important cytoprotective mechanism. It is well-studied and described that Nrf2 can regulate the expression of mitochondrial-targeted antioxidant systems in the cell, indirectly protecting mtDNA from damage. However, the Nrf2/ARE pathway can also directly impact on the mtDNA repair processes. In this review, we summarize the existing data on the impact of Nrf2 on mtDNA repair, primarily base excision repair (BER), as it is considered the main repair pathway for the mitochondrial genome. We explore the crosstalk between Nrf2/ARE, BRCA1, and p53 signaling pathways in their involvement in maintaining mtDNA integrity. The role of other repair mechanisms in correcting mismatched bases and double-strand breaks is discussed. Additionally, the review addresses the role of Nrf2 in the repair of noncanonical bases, which contribute to an increased number of mutations in mtDNA and can contaminate the nucleotide pool.
Topics: NF-E2-Related Factor 2; DNA, Mitochondrial; Humans; DNA Repair; Signal Transduction; Antioxidant Response Elements; Animals; BRCA1 Protein; Tumor Suppressor Protein p53; DNA Damage
PubMed: 38940042
DOI: 10.31083/j.fbl2906218 -
ISME Communications Jan 2024The majority of bacteriophage diversity remains uncharacterized, and new intriguing mechanisms of their biology are being continually described. Members of some phage...
The majority of bacteriophage diversity remains uncharacterized, and new intriguing mechanisms of their biology are being continually described. Members of some phage lineages, such as the , repurpose stop codons to encode an amino acid by using alternate genetic codes. Here, we investigated the prevalence of stop codon reassignment in phage genomes and its subsequent impacts on functional annotation. We predicted 76 genomes within INPHARED and 712 vOTUs from the Unified Human Gut Virome Catalogue (UHGV) that repurpose a stop codon to encode an amino acid. We re-annotated these sequences with modified versions of Pharokka and Prokka, called Pharokka-gv and Prokka-gv, to automatically predict stop codon reassignment prior to annotation. Both tools significantly improved the quality of annotations, with Pharokka-gv performing best. For sequences predicted to repurpose TAG to glutamine (translation table 15), Pharokka-gv increased the median gene length (median of per genome median) from 287 to 481 bp for UHGV sequences (67.8% increase) and from 318 to 550 bp for INPHARED sequences (72.9% increase). The re-annotation increased median coding capacity from 66.8% to 90.0% and from 69.0% to 89.8% for UHGV and INPHARED sequences predicted to use translation table 15. Furthermore, the proportion of genes that could be assigned functional annotation increased, including an increase in the number of major capsid proteins that could be identified. We propose that automatic prediction of stop codon reassignment before annotation is beneficial to downstream viral genomic and metagenomic analyses.
PubMed: 38939532
DOI: 10.1093/ismeco/ycae079 -
PeerJ 2024White-rot fungi and bacteria communities are unique ecosystems with different types of symbiotic interactions occurring during wood decomposition, such as cooperation,...
Sequence and structure analyses of lytic polysaccharide monooxygenases mined from metagenomic DNA of humus samples around white-rot fungi in Cuc Phuong tropical forest, Vietnam.
BACKGROUND
White-rot fungi and bacteria communities are unique ecosystems with different types of symbiotic interactions occurring during wood decomposition, such as cooperation, mutualism, nutritional competition, and antagonism. The role of chitin-active lytic polysaccharide monooxygenases (LPMOs) in these symbiotic interactions is the subject of this study.
METHOD
In this study, bioinformatics tools were used to analyze the sequence and structure of putative LPMOs mined by hidden Markov model (HMM) profiles from the bacterial metagenomic DNA database of collected humus samples around white-rot fungi in Cuc Phuong primary forest, Vietnam. Two genes encoding putative LPMOs were expressed in and purified for enzyme activity assay.
RESULT
Thirty-one full-length proteins annotated as putative LPMOs according to HMM profiles were confirmed by amino acid sequence comparison. The comparison results showed that although the amino acid sequences of the proteins were very different, they shared nine conserved amino acids, including two histidine and one phenylalanine that characterize the H1-Hx-Yz motif of the active site of bacterial LPMOs. Structural analysis of these proteins revealed that they are multidomain proteins with different functions. Prediction of the catalytic domain 3-D structure of these putative LPMOs using Alphafold2 showed that their spatial structures were very similar in shape, although their protein sequences were very different. The results of testing the activity of proteins GL0247266 and GL0183513 show that they are chitin-active LPMOs. Prediction of the 3-D structures of these two LPMOs using Alphafold2 showed that GL0247266 had five functional domains, while GL0183513 had four functional domains, two of which that were similar to the GbpA_2 and GbpA_3 domains of protein GbpA of bacteria. The GbpA_2 - GbpA_3 complex was also detected in 11 other proteins. Based on the structural characteristics of functional domains, it is possible to hypothesize the role of chitin-active GbpA-like LPMOs in the relationship between fungal and bacterial communities coexisting on decomposing trees in primary forests.
Topics: Vietnam; Mixed Function Oxygenases; Forests; Chitin; Metagenomics; Metagenome; Amino Acid Sequence
PubMed: 38938609
DOI: 10.7717/peerj.17553 -
Clinical and Experimental Dental... Aug 2024The human oral microbiome, a complex ecosystem linked to oral and systemic health, harbors a diverse array of microbial populations, including antimicrobial resistance...
OBJECTIVES
The human oral microbiome, a complex ecosystem linked to oral and systemic health, harbors a diverse array of microbial populations, including antimicrobial resistance genes (ARGs). As a critical component of the One Health approach to tackle antibiotic resistance, comprehending the oral resistome's composition and diversity is imperative. The objective of this study was to investigate the impact of chemical cell lysis treatment using MetaPolyzyme on the detectability of the oral microbiome, resistome, and DNA quality and quantity.
MATERIALS AND METHODS
Saliva samples were collected from five healthy individuals, and each of the samples was subjected to DNA extraction with and without the treatment with MetaPolyzyme. Through metagenomic sequencing, we analyzed, assessed, and compared the microbial composition, resistome, and DNA characteristics between both groups of extracted DNA.
RESULTS
Our study revealed that MetaPolyzyme treatment led to significant shifts in the detectability of microbial composition, favoring Gram-positive bacteria, notably Streptococcus, over Gram-negative counterparts. Moreover, the MetaPolyzyme treatment also resulted in a distinct change in ARG distribution. This shift was characterized by an elevated proportion of ARGs linked to fluoroquinolones and efflux pumps, coupled with a reduction in the prevalence of tetracycline and β-lactam resistance genes when compared with the nontreated group. Alpha diversity analysis demonstrated altered species and ARG distribution without affecting overall diversity, while beta diversity analysis confirmed significant differences in the taxonomical composition and oral resistome between treated and nontreated groups.
CONCLUSIONS
These findings underscore the critical role of cell lysis treatment in optimizing oral metagenomic studies and enhance our understanding of the oral resistome's dynamics in the context of antimicrobial resistance.
Topics: Saliva; Humans; Microbiota; DNA, Bacterial; Metagenomics; Metagenome; Drug Resistance, Bacterial; Mouth; Adult; Anti-Bacterial Agents; Male; Female; Healthy Volunteers
PubMed: 38938117
DOI: 10.1002/cre2.905 -
Bioresource Technology Jun 2024Anaerobic ammonia oxidation (anammox) is a cost-effective technology but its performance can be seriously inhibited by high load stress. This study has created an...
Anaerobic ammonia oxidation (anammox) is a cost-effective technology but its performance can be seriously inhibited by high load stress. This study has created an innovative iron-rich encrustation layer (IEL) on the surface of anammox granules (AnGS) through the addition of a certain amount of nano zero-valent iron. The IEL was formed through the aggregation of a gel network and the binding of iron species with extracellular polymeric substances (EPS), resulting in a significant increase in settling ability, EPS secretion, and heme content. Metagenomic analysis indicated a notable rise in the functional genes associated with nitrogen andiron metabolism in IEL AnGS. Under high load stress, the ammonia removal performance of AnGS without IEL severely declined. In contrast, IEL AnGS exhibited excellent ammonia removal efficiency of over 90%. The IEL served as a protective barrier for AnGS, effectively mitigating the strong shear forces, thereby enhancing their resistance to high load stress.
PubMed: 38936676
DOI: 10.1016/j.biortech.2024.131046 -
International Journal of Antimicrobial... Jun 2024Urinary tract infections (UTIs) are one of the main reasons for antibiotic prescriptions in primary care. Recent studies demonstrate similar clinical outcomes with...
BACKGROUND
Urinary tract infections (UTIs) are one of the main reasons for antibiotic prescriptions in primary care. Recent studies demonstrate similar clinical outcomes with shorter antibiotics courses. Here, we investigated the differential collateral effect of ciprofloxacin treatment duration on the gastrointestinal and oropharyngeal microbiome in patients presenting with uncomplicated UTI to primary care practices in Switzerland, Belgium and Poland.
METHODS
Stool and oropharyngeal samples were obtained from 36 treated patients and 14 controls at the beginning of antibiotic therapy, end of therapy and one month after end of therapy. Samples underwent shotgun metagenomics.
RESULTS
At the end of therapy, patients treated with both shorter (≤7 days) and longer (>7 days) ciprofloxacin courses showed similar changes in the gastrointestinal microbiome compared to non-treated controls. After one month, most changes in patients receiving shorter courses were reversed; however, longer courses led to increased abundance of the genera Roseburia, Faecalicatena and Escherichia. Changes in the oropharynx were minor and reversed to baseline levels within one month. Ciprofloxacin resistance encoding mutations in gyrA/B and parC/E reads were observed in both treatment groups, which decreased to baseline levels after one month. An increased abundance of resistance genes was observed in the gastrointestinal microbiome after longer treatment, and correlated to increased prevalence of aminoglycoside, beta-lactam, sulphonamide, and tetracycline resistance genes.
CONCLUSION
Collateral effects on the gastrointestinal community, including an increased prevalence of antimicrobial resistance genes, persists at least up to one month following longer ciprofloxacin therapy. Our data, therefore, support the use of shorter treatment duration.
PubMed: 38936492
DOI: 10.1016/j.ijantimicag.2024.107259 -
Journal of Environmental Management Jun 2024The simultaneous escalation in ARGs (antibiotic resistance genes) and MRGs (metal resistance genes) further complicates the intricate network of factors contributing to...
The simultaneous escalation in ARGs (antibiotic resistance genes) and MRGs (metal resistance genes) further complicates the intricate network of factors contributing to the proliferation of microbial resistance. Manganese, which has been reported to affect the resistance of bacteria to antibiotics and metals, plays a vital role in microbial nitrogen metabolism. Moreover, nitrifying and denitrifying populations are potential hosts for ARGs. In this study, manganese was introduced in its prevalent organic chelated form in the environment (Manganese humus chelates, Mn-HA) to a N metabolism sludge to explore the effect of manganese on MRGs and ARGs dissemination. Metagenomics results revealed that manganese availability enhances nitrogen metabolism, while a decrease in ARGs was noted which may be attributed to the inhibition of horizontal gene transfer (HGT), reflected in the reduced integrase -encoded gene int. Population analysis revealed that nitrifier and denitrifier genus harbor MRGs and ARGs, indicating that nitrifier and denitrifier are hosts of MRGs and ARGs. This raises the question of whether the prevalence of ARGs is always increased in metal-contained environments.
PubMed: 38936019
DOI: 10.1016/j.jenvman.2024.121615 -
Microbial Ecology Jun 2024Antimicrobial resistance (AMR) is a major public health threat, exacerbated by the ability of bacteria to rapidly disseminate antimicrobial resistance genes (ARG). Since...
Antimicrobial resistance (AMR) is a major public health threat, exacerbated by the ability of bacteria to rapidly disseminate antimicrobial resistance genes (ARG). Since conjugative plasmids of the incompatibility group P (IncP) are ubiquitous mobile genetic elements that often carry ARG and are broad-host-range, they are important targets to prevent the dissemination of AMR. Plasmid-dependent phages infect plasmid-carrying bacteria by recognizing components of the conjugative secretion system as receptors. We sought to isolate plasmid-dependent phages from wastewater using an avirulent strain of Salmonella enterica carrying the conjugative IncP plasmid pKJK5. Irrespective of the site, we only obtained bacteriophages belonging to the genus Alphatectivirus. Eleven isolates were sequenced, their genomes analyzed, and their host range established using S. enterica, Escherichia coli, and Pseudomonas putida carrying diverse conjugative plasmids. We confirmed that Alphatectivirus are abundant in domestic and hospital wastewater using culture-dependent and culture-independent approaches. However, these results are not consistent with their low or undetectable occurrence in metagenomes. Therefore, overall, our results emphasize the importance of performing phage isolation to uncover diversity, especially considering the potential of plasmid-dependent phages to reduce the spread of ARG carried by conjugative plasmids, and to help combat the AMR crisis.
Topics: Plasmids; Wastewater; Bacteriophages; Genome, Viral; Escherichia coli; Host Specificity; Pseudomonas putida; Salmonella enterica; Phylogeny
PubMed: 38935220
DOI: 10.1007/s00248-024-02401-3