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Whole genome sequencing of unusual Hepatitis C virus subtypes and drug resistance analysis during direct-acting antiviral therapy in India.

INTRODUCTION AND OBJECTIVES: Pangenotypic direct-acting antivirals (DAA) are effective against highly prevalent Hepatitis C virus (HCV) subtypes, but have been clinically validated almost exclusively in high-income countries. Unusual HCV subtypes may carry natural polymorphisms, potentially impacting DAA susceptibility. We conducted full-genome characterization and resistance analysis of unusual HCV subtypes in patients receiving DAA treatment. PATIENTS AND METHODS: In this prospective hospital-based study, eligible patients were screened for anti-HCV antibodies and active infection was confirmed by diagnostic 5'NCR-based HCV RNA detection. Genotyping was performed by core region sequencing, and viral load quantified by real-time PCR. For whole genome sequencing, multiplex primers were designed using alignments of global reference sequences. Sequencing was carried out using the Oxford Nanopore Technology platform. Phylogenetic analysis used multiple sequence alignment and the HCV-GLUE resource for resistance-associated substitution (RAS) analysis. RESULTS: Predominant genotype was genotype 3 in 64.3% (n = 45); genotype 6 in 21.4% (n = 15); and genotype 1 in 14.2% (n = 10). Unusual HCV subtype 6xa was detected in two patients and showed no NS5A resistance mutations. One genotype 3b patient relapsed at 24 weeks post-DAA treatment completion and carried NS5A resistance-associated substitutions 30 K and 31 M both at baseline and at relapse, conferring high-level resistance to NS5A inhibitors. CONCLUSION: This is the first report from India of whole genome sequencing of HCV subtype 6xa. The identification of NS5A resistance mutations in the 3b relapse case underscores challenges for global HCV elimination strategies.

Humans↗

Chromosome scale genomes of two invasive Adelges species enable virtual screening for selective adelgicides.

Two invasive hemipteran adelgids are associated with widespread damage to several North American conifer species. Adelges tsugae, hemlock woolly adelgid, was introduced from Japan and reproduces parthenogenetically in North America, where it has rapidly decimated Tsuga canadensis and Tsuga caroliniana (the eastern and Carolina hemlocks, respectively). Adelges abietis, eastern spruce gall adelgid, introduced from Europe, forms distinctive pineapple-shaped galls on several native spruce species. While not considered a major forest pest, it weakens trees and increases susceptibility to additional stressors. Broad-spectrum insecticides that are often used to control adelgid populations can have off-target impacts on beneficial insects. Whole genome sequencing was performed on both species to aid in development of targeted solutions that may minimize ecological impact. Adelges abietis was sequenced using Illumina Linked-Read technology from 30 pooled individuals, with Hi-C scaffolding performed using data from a single individual collected from the same host plant. Adelges tsugae used Oxford Nanopore long-read sequencing from pooled nymphs. The assembled A. tsugae and A. abietis genomes, pooled from several parthenogenetic females, are 220.75 Mbp and 253.16 Mbp, respectively. Each consists of eight autosomal chromosomes, as well as two sex chromosomes (X1/X2), supporting the XX-XO sex determination system. The genomes are over 96% complete based on BUSCO assessment. Genome annotation identified 11,424 and 12,060 protein-coding genes in A. tsugae and A. abietis, respectively. Comparative analysis of proteins across 29 hemipteran species and 14 arthropod outgroups identified 31,666 putative gene families. Gene family evolution analysis with CAFE revealed lineage-specific expansions in immune-related aminopeptidases (ERAP1) and juvenile hormone binding proteins (JHBP), contractions in juvenile hormone acid methyltransferases (JHAMT), and conservation of nicotinic acetylcholine receptors (nAChR). These genes were explored as candidate families towards a long-term objective of developing adelgid-selective insecticides. Structural comparisons of proteins across seven focal species (Adelges tsugae, Adelges abietis, Adelges cooleyi, Rhopalosiphum maidis, Apis mellifera, Danaus plexippus, and Drosophila melanogaster) revealed high conservation of nAChR and ERAP1, while JHAMT exhibited species-specific structural divergence. The potential of JHAMT as a lineage-specific target for pest control was explored through virtual drug and pesticide screening.

adelgids↗

Characterization and comparative analysis of the complete mitochondrial genome sequence of Aucklandia lappa Decne.

BACKGROUND: Aucklandia lappa Decne, a precious medicinal herb in China, utilises the dried rhizome as its medicinal part, which riches in volatile oils, sesquiterpene compounds and other active constituents. Although the mitogenome of A. lappa has been assembled, related research remains in its preliminary stages, far from achieving comprehensive and in-depth understanding. RESULTS: In this paper, the complete mitogenome of A. lappa was assembled by employing a hybrid strategy that combined Illumina short-read and Nanopore long-read sequencing. The assembled mitogenome is 436,648 bp in size with a GC content of 45.06%. The mitogenome has only one chromosomal structure, It contains 54 genes, including 31 protein-coding genes(PCG), 19 tRNA genes, and 4 rRNA genes. A total of 32 high-frequency codons exhibiting significant AT-bias, 431 RNA editing sites, and 26 homologous fragments were transferred from the chloroplast to mitochondria genes (7,337 bp, 1.68%). Furthermore, we conducted a phylogenetic analysis involving in A. lappa and 27 other taxa to clarify its evolutionary and taxonomic status. These findings provide a foundation for further understanding the evolutionary relationships within Asteraceae plant. CONCLUSION: Through the assembly and comprehensive analysis of A. lappa mitogenome, This study has for the first time fully elucidated its mitogenomic structural characteristics.These results not only provide high-quality genetic resources for research on the Asteraceae mitogenome but also lay a solid foundation for in-depth exploration of the evolution and functional genomics of medicinal plants in the Asteraceae family.

Genome, Mitochondrial↗

Whole-genome sequences of the dwarf honey bee subgenus Micrapis: Apis andreniformis and Apis florea.

The Micrapis subgenus, which includes the black dwarf honey bee (Apis andreniformis) and the red dwarf honey bee (Apis florea), remains underrepresented in genomic studies despite its ecological significance. Here, we present high-quality de novo genome assemblies for both species, generated using a hybrid sequencing approach combining Oxford Nanopore Technologies long reads with Illumina short reads. The final assemblies are highly contiguous, with contig N50 values of 5.0 Mb (A. andreniformis) and 4.3 Mb (A. florea), representing a major improvement over the previously published A. florea genome. Genome completeness assessments indicate high quality, with BUSCO scores exceeding 98.5% using the Hymenoptera database and k-mer analyses supporting base-level accuracy. Repeat annotation revealed a relatively low repetitive sequence content (∼6%), consistent with other Apis species. Using RNA sequencing data, we annotated 12,189 genes for A. andreniformis and 12,207 genes for A. florea, with ∼98% completeness in predicted proteomes. These genome assemblies provide a valuable resource for comparative and functional genomic studies, with the potential to offer new insights into the genetic basis of dwarf honey bee adaptations.

Male↗

Determining genotype and antimicrobial resistance of Salmonella Typhi in environmental samples by amplicon sequencing.

BACKGROUND: Estimates of the burden of typhoid fever due to Salmonella enterica serovar Typhi (S. Typhi) rely on data from clinical surveillance, which is rarely done in low income settings and is also limited by the poor sensitivity of the assays used and the reliance on health seeking by patients. Environmental surveillance for S. Typhi shed by symptomatic and asymptomatic individuals in wastewater offers a sensitive surveillance tool that could help to inform burden estimates. Sequencing S. Typhi direct from wastewater concentrates has the potential to identify circulating genotypes and associated antimicrobial resistance (AMR) genes, supporting public health interventions such as vaccination and antimicrobial usage. METHODOLOGY AND PRINCIPAL FINDINGS: We designed a multiplex targeted amplicon sequencing protocol for genotyping and determining AMR in S. Typhi from wastewater samples, targeting SNPs that identify genotypes of interest and both chromosomal and plasmid-borne AMR. PCR products were sequenced using the Oxford Nanopore Technologies (ONT) MinION, and genotypes and AMR identified using the GenoTyphi program. We tested this approach on samples from south India from both hospital outflow and wastewater collected from the community. All samples tested were suspected to be positive for S. Typhi following quantitative PCR for ttr, tviB, and staG gene targets. Out of 110 samples tested we were able to determine a genotype and/or AMR for 8. All samples that gave a genotype call suggested a genotype consistent with those found in clinical cases in India during the same time period and produced consensus sequences that clustered with S. Typhi when included in a phylogenetic tree. CONCLUSIONS: In this study, we provide proof of concept data for amplicon sequencing of S. Typhi in wastewater which with further optimisation could be used to complement clinical surveillance data or provide data on S. Typhi presence in the absence of clinical surveillance. This information can inform public health interventions, and the concept could be applied to other pathogens of interest for genotyping from environmental surveillance samples.

Salmonella typhi↗

Parallelizing a DNA simulation code for the Cray MTA-2.

The Cray MTA-2 (Multithreaded Architecture) is an unusual parallel supercomputer that promises ease of use and high performance. We describe our experience on the MTA-2 with a molecular dynamics code, SIMU-MD, that we are using to simulate the translocation of DNA through a nanopore in a silicon based ultrafast sequencer. Our sequencer is constructed using standard VLSI technology and consists of a nanopore surrounded by Field Effect Transistors (FETs). We propose to use the FETs to sense variations in charge as a DNA molecule translocates through the pore and thus differentiate between the four building block nucleotides of DNA. We were able to port SIMU-MD, a serial C code, to the MTA with only a modest effort and with good performance. Our porting process needed neither a parallelism support platform nor attention to the intimate details of parallel programming and interprocessor communication, as would have been the case with more conventional supercomputers.

Algorithms↗

The wastewater microbiome: A novel insight for COVID-19 surveillance.

Wastewater-Based Epidemiology is a tool to face and mitigate COVID-19 outbreaks by evaluating conditions in a specific community. This study aimed to analyze the microbiome profiles using nanopore technology for full-length 16S rRNA sequencing in wastewater samples collected from a penitentiary (P), a residential care home (RCH), and a quarantine or health care facilities (HCF). During the study, the wastewater samples from the RCH and the P were negative for SARS-CoV-2 based on qPCRs, except during the fourth week when was detected. Unexpectedly, the wastewater microbiome from RCH and P prior to week four was correlated with the samples collected from the HCF, suggesting a core bacterial community is expelled from the digest tract of individuals infected with SARS-CoV-2. The microbiota of wastewater sample positives for SARS-CoV-2 was strongly associated with enteric bacteria previously reported in patients with risk factors for COVID-19. We provide novel evidence that the wastewater microbiome associated with gastrointestinal manifestations appears to precede the SARS-CoV-2 detection in sewage. This finding suggests that the wastewaters microbiome can be applied as an indicator of community-wide SARS-CoV-2 surveillance.

COVID-19↗

From regionalization to homogenization: Nationwide metagenomic assessment of priority pathogens and the resistome in Polish hospital wastewater.

Hospital wastewater (HWW) is a critical hotspot for the dissemination of antibiotic resistance genes (ARGs) and pathogens. This study provides the first comprehensive metagenomic characterization of HWW across Poland, analyzing 64 medical facilities across two seasons via Nanopore long-read sequencing (total of 128 HWW samples). The HWW microbiome was mostly dominated by Proteobacteria, Bacteroidota, and Firmicutes. Multivariate analysis confirmed a significant seasonal shift in the resistome. Winter samples exhibited geographic regionalization, with localized hotspots of specific ARGs, including vancomycin resistance (operon van) and carbapenemase genes (blaOXA, blaNDM). Conversely, summer samples showed a significant trend toward nationwide homogenization, characterized by a uniform distribution of ESBL genes (blaTEM, blaCTX-M) and multidrug resistance (MDR) determinants, alongside the persistence of localized clinical hotspots. Klebsiella pneumoniae emerged as a central network hub, particularly in summer, showing strong correlations with ESBLs. Quantitative genomic co-occurrence analysis revealed a functional division within dominant taxa: while environmental species like Acinetobacter johnsonii comprised the general background microbiome, clinical pathogens such as Acinetobacter baumannii served as primary vectors, showing frequent associations with high-risk ARGs. Environmental and opportunistic bacteria, such as Aeromonas spp. and Citrobacter spp., were identified as putative 'bridge hosts' associated with mobile resistance determinants and potentially contributing to HGT. The findings indicate that seasonal factors, such as increased temperature and sub-inhibitory antibiotic concentrations, may contribute to the transition from regionalized to homogenized resistance profiles, demonstrating that background resistome convergence can coexist with point-source clinical outbreaks. This seasonal "blurring" of regional boundaries positions HWW as an active vector for large-scale antimicrobial resistance (AMR) dissemination. These results underscore the urgent need for nationwide metagenomic surveillance and advanced wastewater treatment strategies within the "One Health" framework to mitigate the environmental spread of WHO priority pathogens.

Acinetobacter baumannii↗

Detecting single stranded DNA with a solid state nanopore.

Voltage biased solid-state nanopores are used to detect and characterize individual single stranded DNA molecules of fixed micrometer length by operating a nanopore detector at pH values greater than approximately 11.6. The distribution of observed molecular event durations and blockade currents shows that a significant fraction of the events obey a rule of constant event charge deficit (ecd) indicating that they correspond to molecules translocating through the nanopore in a distribution of folded and unfolded configurations. A surprisingly large component is unfolded. The result is an important milestone in developing solid-state nanopores for single molecule sequencing applications.

DNA, Single-Stranded↗

NanoSSL: attention mechanism-based self-supervised learning method for protein identification using nanopores.

MOTIVATION: Nanopores are cutting-edge interdisciplinary tools that can analyze biomolecules at the single-molecule level for many applications, e.g. DNA sequencing. Efforts are underway to extend nanopores to proteomics, including the development of machine learning algorithms for protein sequencing and identification. However, single-molecule data are intrinsically noisy and hard to process. Moreover, the development and performance of machine learning for nanopore is jeopardized by data scarcity. Self-supervised learning is an emerging method that may yield advantages in nanopore scenarios. RESULTS: We propose and experimentally validate Nanopore analysis using Self-Supervised Learning (NanoSSL), a generative self-supervised learning framework based on attention mechanisms for the identification of protein signals from nanopores. Leveraging a two-step approach consisting of self-supervised pre-training and supervised fine-tuning, NanoSSL learns useful feature representations from empirical data to facilitate downstream classification tasks. Inspired by the concept of fragmentation in conventional protein sequencing technologies, during pretraining each translocation event is split into multiple non-overlapping fragments of equal size, some of which are randomly masked and reconstructed using a masked autoencoder. Learning the feature representations of the reconstructed nanopore events facilitates molecular identification in fine-tuning. In this study, we retested a publicly available nanopore multiplexed protein sensing dataset for model iteration, and subsequently measured Alzheimer's disease biomarker Aβ1-42 using homemade solid-state nanopores. Empirical results indicated NanoSSL achieved an unprecedented performance across four metrics: accuracy, precision, recall, and F1 score, when classifying two mutated Aβ1-42, E22G and G37R. The self-supervised learning and attention mechanism were verified as the source of performance gains. AVAILABILITY AND IMPLEMENTATION: The main program is available at https://doi.org/10.5281/zenodo.17172822.

Nanopores↗

Deposition of DNA-functionalized gold nanospheres into nanoporous surfaces.

We report the deposition of DNA-conjugated gold nanospheres into arrays of surface nanopores obtained from hexagonally ordered thin polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer films on silicon. The deposition occurs spontaneously from aqueous solution and is driven by either electrostatic interactions or specific DNA hybridization events between the DNA nanospheres and the surface nanopores. To mitigate this spontaneous deposition, we have chemically modified the nanopores with either positively charged aminosilanes or oligonucleotide probe sequences. The deposition of DNA nanospheres into the surface nanopores was characterized by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). We have observed preferential immobilization of individual DNA nanospheres within the nanopores, based on the size matching between the two entities. The inclusion density and selectivity of DNA nanosphere deposition into the surface nanopores was found to depend predominantly on the methods through which the nanoporous surfaces were prepared and chemically functionalized.

DNA↗

Whole-genome sequencing of adenovirus 41 directly from wastewater using nested overlapping PCR and MinION.

Human adenovirus F41 (HAdV-F41) is one of the leading causes of children's acute gastroenteritis and was recently linked to an outbreak of severe acute hepatitis of unknown etiology among children during 2021 to 2022. While most evidence is based on clinical data, wastewater-based epidemiology offers a community-level approach to monitoring circulating strains and enhancing outbreak preparedness. In this study, we developed an overlapping amplicon-based whole-genome sequencing approach to directly detect HAdV-F41 from archived wastewater samples, using nested PCR with 13 primer sets. Archived wastewater samples were collected between 2021 and 2022 from three treatment plants in Seattle, USA. The viral load ranged from 1.2 × 103 to 8.4 × 103 genome copies per liter. The Oxford Nanopore platform was used for whole-genome sequencing. Complete or partial (>84%) HAdV-F41 genomes were recovered from wastewater samples, with mean coverage depths ranging from 10³ to 10⁵. The consensus sequences showed more than 99% similarity to reference genomes in the NCBI database. The phylogenetic analysis revealed that 2 sequences clustered within lineage 2a and 11 within lineage 2b, reflecting that at least two sub-lineages were circulating in the community at that time. Our results demonstrate that the overlapping amplicon-based whole-genome sequencing approach using the Oxford Nanopore platform reliably recovers HAdV-F41 genomes from wastewater. This method offers high-resolution genomic surveillance of circulating, clinically relevant HAdV-F41, supporting wastewater-based epidemiology as a valuable tool for detecting emerging variants and strengthening the early warning system for future disease outbreaks.IMPORTANCEHuman adenovirus F41 is a primary cause of childhood gastroenteritis and has been linked to recent outbreaks of severe acute hepatitis in children, yet community-level genomic surveillance of this virus remains limited. This study shows that wastewater can be used to recover nearly complete HAdV-F41 genomes through a targeted overlapping-amplicon sequencing strategy on the Oxford Nanopore platform. By applying this method to archived wastewater samples, we detected the simultaneous circulation of multiple viral lineages in a large city. These findings extend wastewater-based epidemiology beyond SARS-CoV-2 and emphasize its importance for monitoring clinically significant enteric viruses. The method described here offers a scalable tool for tracking viral evolution in communities and enhancing early warning systems for future outbreaks.

Wastewater↗

Whole-Genome Analysis of Bacillus Licheniformis Ali5 and Synthesis of Lichenysin via Genome Shuffling.

Whole-genome sequencing of Bacillus licheniformis Ali5 was performed via MGI-seq PE150 and Nanopore single-molecule real-time sequencing. The strain has a 4,114,664 bp circular genome encoding 4030 protein-coding genes. Functional annotation across NR, COG, GO, KEGG, CARD, BacMet, and CAZy databases identified 4025, 2812, 988, 1242, 72, 69, and 94 corresponding genes, respectively, and antiSMASH 6.0 revealed multiple antimicrobial biosynthetic gene clusters, including intact lichenysin and lichenicidin VK21 A1/A2 gene clusters. Three rounds of recursive protoplast fusion-based genome shuffling, paired with a dual-index screening system, significantly improved strain growth and lichenysin biosynthesis. Recombinants exhibited shortened lag phase, enhanced proliferation, improved stationary-phase stability, and higher diauxic peak biomass. PP3-176 and PP3-186 showed 4.6%-8.1% higher 12-h shake-flask titer and 3.1%-4.0% higher maximum titer than the parental average, with excellent fermentation stability. 1-L bioreactor validation confirmed strong scale-up potential. PP3-186 achieved 27.2% and 31.6% titer increases at 12 h and 20 h, while PP3-176 yielded 20.4% and 14.6% improvements with robust metabolic performance. This study validates genome shuffling as an effective strategy for enhancing lichenysin production, providing candidate strains and technical support for industrial application.

Bacillus licheniformis↗

The reference genome of the human diploid cell line RPE-1.

Recent technological advances have facilitated the assembly of telomere-to-telomere (T2T) genomes. The current T2T CHM13 showcases the complete architecture of the human genome, yet its use in functional experiments is limited by discrepancies with the actual genome of the specific biological system under study. Access to reference assemblies for experimentally relevant cell lines is therefore essential in advancing sequencing-based analyses and precise manipulation, particularly in highly variable regions such as centromeres. Here, we present RPE1v1.1, the near-complete diploid genome assembly of the hTERT RPE-1 cell line, a non-cancerous human retinal epithelial model with a stable karyotype. Using high-coverage Pacific Biosciences and Oxford Nanopore Technologies long-read sequencing, we generate a high-quality de novo assembly, validate it through multiple methods, and phase it by integrating high-throughput chromosome conformation capture (Hi-C) data. Our assembly includes chromosome-level scaffolds that span centromeres for all chromosomes. Comparing both haplotypes with the CHM13 genome, we detect haplotype-specific genomic variations, including the translocation between chromosome 10 and chromosome X t(X;10)(Xq28;10q21.2) characteristic of RPE-1 cells, and divergence peaking at centromeres. Altogether, the RPE1v1.1 genome provides a reference-quality diploid assembly of a widely used cell line, supporting high-precision genetic and epigenetic studies in this model system.

Humans↗

Detecting and reconstructing breakage-fusion-bridge cycles from long-read sequencing using BFBArchitect.

MOTIVATION: Focal oncogene amplification is a key driver of tumor progression. Remarkably, the increased pathology depends on the context-whether the amplification is extrachromosomal (ecDNA) or intrachromosomal. EcDNA amplifications promote heterogeneity, therapy resistance, and poor prognosis. Focal intrachromosomal amplifications often arise through breakage-fusion-bridge (BFB) cycles, which produce highly rearranged but stable chromosomes. Distinguishing BFB from ecDNA remains challenging due to overlapping genomic signatures. To address this, we present BFBArchitect, a computational method leveraging long-read Oxford Nanopore data to identify BFB sequences consistent with both copy number and structural variations. RESULTS: We provide a novel combinatorial characterization of BFB, which naturally leads to an integer linear programming (ILP) optimization. The ILP optimization generates a BFB sequence that best explains experimentally observed copy numbers and foldback structural variants. We implement this idea in a tool called BFBArchitect, which achieves near-perfect accuracy in distinguishing BFB from non-BFB structures in extensive simulations as well as on 18 validated tumor samples. Moreover, it generates sequence-level BFB reconstructions that provide mechanistic insights into BFB formation, including repair mechanisms with template switching and other structural variants, and recapture of telomere for stabilization. AVAILABILITY AND IMPLEMENTATION: BFBArchitect is available at https://github.com/AmpliconSuite/BFBArchitect.

Sequence Analysis, DNA↗

Unlocking the unexplored AMPSphere in marine rare species.

BACKGROUND: Antimicrobial peptides (AMPs) have advantages over traditional antibiotics in fighting against drug-resistant bacterial infections. Natural microbial communities are considered as the priority targets for next-generation AMP bioprospecting initiatives. While progress has been made in characterizing AMPs from the dominant microbial taxa in natural ecosystems, current research largely overlooks the biosynthetic potential of rare species. Given their distinct evolutionary pressures, rare species likely produce AMPs with novel structures and unconventional mechanisms of action. RESULTS: In this study, enrichment cultivation of a marine biofilm was conducted in 138 carbon source- and oxygen level-based conditions, followed by metagenomic sequencing using both Illumina and Nanopore platforms. Analysis of 435 high-quality genomes derived from the metagenomes suggests that these bacterial strains are significantly underrepresented (<&#x2009;0.01%) in global marine biofilm communities. Through multi-model prediction, we identified 3,054,472 candidate AMPs from the genomes, including 1048 high-confidence ones, thereby significantly expanding the previously known AMPSphere. Furthermore, AMPs derived from the rare bacterial species exhibit unique sequence characteristics, structural diversity, remarkable stability under diverse pH conditions and pepsin exposure, and strong therapeutic potential in animal models, reflecting their specialized adaptive and defensive strategies developed within ecological systems. CONCLUSIONS: The features of the underexplored AMPs from low-abundance bacteria in marine biofilms provide valuable resources and theoretical foundations for the development of highly effective antimicrobial agents. Video Abstract.

Biofilms↗