Biology subjects

Osabutey, D.

Publications and source records attributed to Osabutey, D..

3 recordsLinked to original sources

bioRxiv2026

Laboratory adaptation and complete genome assembly of a Beposo, Ghana strain of the human hookworm Necator americanus

Laboratory models are invaluable tools for studying parasite biology and pathogenesis, especially for helminth infections. However, the complex life cycles and frequently narrow host specificity of helminths present challenges to maintaining access to critical parasite material in a laboratory setting. This is especially true of Necator americanus, the most common species of hookworm that infects humans globally. Here we report the successful laboratory adaptation of an African strain of N. americanus, originally isolated from infected individuals in Beposo, Ghana. The Beposo strain has been successfully passaged across 9 generations in Golden Syrian hamsters maintained on oral dexamethasone. Differential susceptibility to mebendazole and albendazole was evaluated using an egg hatch assay, and DNA sequencing of the beta-tubulin isotype 1 gene did not identify known resistance-associated mutations in the endemic strain. Sequencing of the mitochondrial COX1 gene revealed that specimens of N. americanus from Ghana, along with reported sequences from Togo, are distinct from those from South America and Asia. Complementary microsatellite-based population analysis revealed substantial genetic variation in the founding parasite population. To further characterize the novel Beposo strain, a draft hybrid genome assembly was generated from genomic DNA extracted from a single adult male worm via an optimized Oxford Nanopore Technologies MinION library preparation approach tailored to low-input sample types. This high-quality assembly, including a complete mitogenome, is 202.8Mb in 950 contigs with an N50 >449 kb. It contains >95% of conserved nematode orthologs in complete single copy and is estimated by homology-based gene prediction to contain 12,804 genes. This study represents the first comprehensive characterization of a strain of N. americanus originating in Africa that has been successfully adapted to a laboratory animal model.

microbiology↗

bioRxiv2026

Hookworm genomic diversity and population structure from accessible sample types: A validated approach to generate genome-wide polymorphism datasets from individual third-stage larvae

Hookworm infection is a neglected tropical disease affecting hundreds of thousands of people annually in the tropics and sub-tropics. Population genomic approaches have the potential to improve our understanding of hookworm infection dynamics and control efficacy. Here, we validate an approach to generate genome-wide polymorphism datasets from accessible sample types in the zoonotic hookworm (Ancylostoma ceylanicum) then apply the validated approach in the human hookworm (Necator americanus) to compare laboratory- and field-derived samples. We first present an optimized method for purifying nucleic acid from individual third-stage hookworm larvae (L3s). We then measure the accuracy of variant call datasets generated through whole genome amplification (WGA) and next-generation sequencing (NGS). We demonstrate that WGA via multiple displacement amplification (MDA) introduces predictable biases that are exacerbated by low inputs and poor sample preservation but show that with sufficient input mass ([≥]0.1ng) we are still able to produce highly accurate variant call datasets from nucleic acid concentrations that reflect those of individual L3s. Using our validated approach, we infer laboratory- and field-collected samples of N. americanus as distinct populations, with higher levels of heterozygosity and nucleotide diversity identified in field-collected samples, suggesting signatures of inbreeding and/or drift are detectable in laboratory specimens within several years of initiation of infection. We also show that, despite expected reductions in heterozygosity, laboratory samples still possess numerous heterozygous sites, and we demonstrate that a reference genome generated from an adult worm from an early laboratory passage performs well for variant calling in both laboratory- and field-derived samples. Moving forward, our optimized method for nucleic acid purification can be broadly applied to generate input for any amplification-based approach where sequencing individual hookworm L3s, rather than a pool of specimens, is preferred. Our validated population genomics workflow can be used to characterize structure and connectivity of hookworm populations in endemic communities, with the goal of leveraging these insights to improve our approach to hookworm treatment and control. AUTHOR SUMMARYInfection with the human hookworm, Necator americanus, is a significant cause of morbidity in the global south. Population genomic techniques have the potential to improve our understanding of hookworm infection and control. However, third-stage larvae, or L3, which are the hookworm life-cycle stage we routinely have access to when screening infected people, are less than a millimeter long, and this small size makes generating genomic datasets from individual worms difficult. Here, we introduce an optimized approach for purifying DNA from individual L3s and validate its use with whole genome amplification (WGA) for population genomics. We found that WGA from L3s produces sequencing datasets that are biased in their breadth and depth of coverage across the hookworm genome. But by ensuring a minimum threshold for the mass of DNA input to WGA and setting strict criteria for variant filtration, these biases can be overcome to produce highly accurate variant calls genome-wide. We then use this approach to demonstrate reduced genetic diversity in a recently established laboratory hookworm strain as compared to field-collected samples. Our study outlines a specimen-through-analysis workflow that can be used with accessible sample types to measure population structure and diversity of hookworms in endemic communities.

genomics↗

bioRxiv2024

Two Key Actinomycetota Taxa in the Human Gut Microbiota are Associated with Schistosoma mansoni Infection Burden

In this study, we sought to identify key microbial taxa associated with human gut dysbiosis during S. mansoni infection and whether the changes are linked to the intensity of helminth infection. Stool samples were obtained from 20 persons infected with schistosomiasis and an equal number of uninfected persons from an endemic rural community in Ghana. Infection intensity was scored as egg count per gram (EPG) using the Kato-Katz method. Positive stool samples were further stratified as low-moderate (<400 EPG, n=15) and high (>400 EPG, n=5) infection burden. The composition and diversity of the gut microbiota and potential microbial markers associated with S. mansoni infection intensity were determined from 16S rRNA amplicon sequence analyses. No difference in {beta}-diversity was observed between positives and negatives (PERMANOVA: R2= 0.012, p= 0.723), although there was an increased abundance of Bifidobacterium (p= 0.008) in infected stool samples compared to the negatives. Further analyses showed that Bifidobacterium (p= 0.003) and Collinsella (p= 0.029) were elevated considerably among the low-moderate infected samples, while the pathobiont Escherichia-Shigella was reduced (p= 0.0078). Our findings show that intestinal schistosomiasis results in human gut microbiota dysbiosis, which is only distinguished when the intensity of infection is considered, with two key Actinomycetota species assuming importance depending on the infection burden. Author SummaryThis study investigates the relationship between Schistosoma mansoni infections, a major cause of intestinal schistosomiasis, and the human gut microbiome. Using samples from an endemic region in Ghana, the research examines how infection intensity impacts gut bacteria. The findings reveal that certain beneficial bacteria, such as Bifidobacterium and Collinsella, become more abundant in cases of low to moderate infection, potentially maintaining immune regulation and gut health. However, these effects are not seen in high-infection instances, possibly due to the aggressive hallmarks of high-intensity helminth infections. Understanding these dynamics could be pivotal for developing microbiome-based interventions to improve treatment outcomes for schistosomiasis and similar parasitic infections. This study sheds light on the complex interplay between infectious parasites and gut microbes, emphasising the promise of microbiome research in enhancing public health efforts in areas where parasitic diseases persist.

genomics↗