Biology subjects

Kasaragod, S.

Publications and source records attributed to Kasaragod, S..

4 recordsLinked to original sources

bioRxiv2026

Spectronaut-nf: A Nextflow Pipeline for Parallel Processing of DIA Data with Spectronaut

SummaryContemporary proteomics methods can now generate large-scale DIA datasets of thousands of files that demand substantial computational resources for efficient analysis. Spectronaut is a widely used platform for DIA data processing; however, large-scale searches are often constrained by computational performance and long execution times when run on single workstations. Here, we present Spectronaut-nf, a Nextflow-based pipeline that enables scalable and parallelized execution of Spectronaut analyses across high-performance computing (HPC) environments. The workflow divides directDIA analysis into modular stages, including spectral library generation, DIA searching, and merging results, allowing efficient distribution of tasks across multiple compute nodes. Benchmarking using 72 diaPASEF raw files using typical hardware demonstrated that Spectronaut-nf completed searches in 23.77 hours, compared with 39.09 hours on a Windows workstation and 67.04 hours on a single-node Linux HPC setup. Stress testing with 1,037 diaPASEF raw files further demonstrated the scalability and robustness of the workflow for large proteomics datasets. Across platforms, protein and peptide identifications remained consistent, with only minimal variability attributable to platform-specific differences. Overall, Spectronaut-nf provides a flexible, scalable, and efficient framework for high-throughput DIA proteomics analysis in HPC environments. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=129 SRC="FIGDIR/small/741433v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@4a7107org.highwire.dtl.DTLVardef@14287d8org.highwire.dtl.DTLVardef@e484e9org.highwire.dtl.DTLVardef@d21c07_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2026

One Health genomic surveillance reveals structured urban rabies transmission and major surveillance gaps

Persistent local foci remain a barrier to eliminating dog-mediated rabies. The processes sustaining micro-scale transmission, particularly in complex urban systems, remain poorly understood. We apply an integrated One Health genomic epidemiology framework to reconstruct a decade-long rabies virus (RABV) epidemic in Arequipa, Peru. Combining 133 new whole genomes with existing data, we produce the most comprehensive canine RABV dataset in Latin America and use whole-genome-informed phylogenetic, phylodynamic, and landscape analyses, to trace the epidemic from its first detection in 2015. Transmission was dominated by a single lineage estimated to be introduced around 2012, which spread for approximately 3 years before detection. We find that only 1-2% of infections are routinely detected, revealing extensive cryptic transmission and undermining case-based metrics for verifying disease freedom. Additional regional and transboundary introductions were detected, but only one resulted in sustained transmission. Within Arequipa city, transmission is highly structured, concentrated in densely populated and socioeconomically deprived areas, and shaped by urban connectivity, with roads and dry water channels facilitating spread and rivers acting as partial barriers. Together, our findings demonstrate that rabies persistence reflects interacting processes across spatial scales and support genomic-informed, spatially targeted surveillance and control strategies.

evolutionary biology↗

bioRxiv2024

Genomic Characterization of a Dog-Mediated Rabies Outbreak in El Pedregal, Arequipa, Peru

BackgroundRabies, a re-emerging zoonosis with the highest known human case fatality rate, has been largely absent from Peru, except for endemic circulation in the Puno region on the Bolivian border and re-emergence in Arequipa City in 2015, where it has persisted. In 2021, an outbreak occurred in the rapidly expanding city of El Pedregal near Arequipa, followed by more cases in 2022 after nearly a year of epidemiological silence. While currently under control, questions persist regarding the origin of the El Pedregal outbreak and implications for maintaining rabies control in Peru. MethodsWe sequenced 25 dog rabies virus (RABV) genomes from the El Pedregal outbreak (n=11) and Arequipa City (n=14) from 2021-2023 using Nanopore sequencing in Peru. Historical genomes from Puno (n=4, 2010-2012) and Arequipa (n=5, 2015-2019), were sequenced using an Illumina approach in the UK. In total, 34 RABV genomes were analyzed, including archived and newly obtained samples. The genomes were analyzed phylogenetically to understand the outbreaks context and origins. ResultsPhylogenomic analysis identified two genetic clusters in El Pedregal: 2021 cases stemmed from a single introduction unrelated to Arequipa cases, while the 2022 sequence suggested a new introduction from Arequipa rather than persistence. In relation to canine RABV diversity in Latin America, all new sequences belonged to a new minor clade, Cosmopolitan Am5, sharing relatives from Bolivia, Argentina, and Brazil. ConclusionGenomic insights into the El Pedregal outbreak revealed multiple introductions over a 2-year window. Eco-epidemiological conditions, including migratory worker patterns, suggest human-mediated movement drove introductions. Despite outbreak containment, El Pedregal remains at risk of dog-mediated rabies due to ongoing circulation in Arequipa, Puno, and Bolivia. Human-mediated movement of dogs presents a major risk for rabies re-emergence in Peru, jeopardizing regional dog-mediated rabies control. Additional sequence data is needed for comprehensive phylogenetic analyses.

genomics↗

bioRxiv2024

Understanding the Transfer and Persistence of Antimicrobial Resistance in Aquaculture Using a Model Teleost Gut System

The development, progression, and dissemination of antimicrobial resistance (AMR) is determined by interlinked human, animal, and environmental drivers, posing severe risks to human health. Conjugative plasmid transfer drives the rapid dissemination of AMR among bacteria. Besides antibiotic judicious use and implementation of antibiotic stewardship programs, mitigating antibiotic resistance spread requires an understanding of the dynamics of AMR transfer among microbial communities, as well as the role of various microbial taxa as potential reservoirs that promote long term AMR persistence. Here, we employed Hi-C, a high-throughput, culture-free technique, combined with qPCR, to monitor carriage and transfer of a multidrug-resistant plasmid within an Atlantic salmon in vitro gut model during florfenicol treatment, a benzenesulfonyl antibiotic widely deployed in fin-fish aquaculture. Microbial communities from the pyloric ceaca of three healthy adult farmed salmon were inoculated into three bioreactors developed for the SalmoSim gut system. The model system was then inoculated with an Escherichia coli strain ATCC 25922 carrying plasmid pM07-1 and treated with florfenicol at a concentration of 150 mg/L fish feed media for five days prior to a washout/recovery phase. Hi-C and metagenomic sequencing identified numerous transfer events, including to gram-negative and gram-positive taxa and, crucially, continuing transfer and persistence of the plasmid once florfenicol treatment had been withdrawn. Our findings highlight the role of commensal teleost gut flora as a reservoir for AMR, and our system provides a model to study how different treatment regimes and interventions may be deployed to mitigate AMR persistence.

microbiology↗