Bedoya-Urrego, K. | Search bioRxiv

bioRxiv2026

A Ribosomal Marker-Based Metataxonomic Framework for Environmental Surveillance of Nematodes of Public Health Importance

Metataxonomic analysis targeting the V4 region of the 18S rDNA gene, combined with molecular phylogenetic inference, was applied to detect nematode DNA of public health relevance in environmental matrices. A total of 25 mOTUs corresponding to six nematode taxa were detected in environmental samples from the Andean region of Colombia. Analysis of 12 water and sludge samples from wastewater treatment plants, 5 artisanal agricultural bioinputs, and 3 food samples revealed multiple species of public health significance: Trichuris trichiura, Enterobius vermicularis, Ascaris spp., and Necator americanus. We also confirmed zoonotic species, including Angiostrongylus cantonensis and Trichinella spp. These findings demonstrate that combining metataxonomics with molecular phylogeny provides a scalable molecular framework for the environmental surveillance of parasitic nematodes, overcoming the limitations of traditional morphological identification methods. This approach offers a replicable model for strengthening control and monitoring programs for parasitism in human populations.

microbiology↗

bioRxiv2025

Uncovering the Hidden Yeast Diversity in Fermented Coffee: Insights from a Shotgun Metagenomic Approach

Yeasts play a pivotal role in coffee fermentation, shaping microbial succession and contributing to the development of final flavor profiles. Despite their importance, yeast taxonomy in this context remains poorly resolved. Traditional classification methods often result in misidentifications due to the limited resolution of classical microbiological techniques and the rapidly evolving taxonomic framework driven by advances in phylogenomic. Moreover, the diversity of budding yeasts in coffee fermentations remains underexplored using high-resolution approaches such as metagenomics. To address this gap, we applied a shotgun metagenomic strategy and reconstructed metagenome-assembled genomes (MAGs) from multiple coffee fermentation samples and, using a robust phylogenomic framework based on 832 conserved single-copy genes. We confidently classified 24 yeast MAGs within the subphylum Saccharomycotina. These included well-known taxa such as Pichia kluyveri, Hanseniaspora spp., Torulaspora delbrueckii, and members of the Kurtzmaniella clade. Most MAGs were placed in strongly supported monophyletic groups (ultrafast bootstrap = 100), with short intra-clade branch lengths indicative of intraspecific variation. Pichia kluyveri emerged as the most abundant and widespread species, detected in all analyzed metagenomes, followed by Hanseniaspora spp. Our results underscore the power of high-resolution phylogenomic for classifying yeast MAGs and highlight the ecological importance of Pichia, Hanseniaspora, Torulaspora, and Kurtzmaniella in spontaneous coffee fermentations.

microbiology↗