Biology subjects

Teixeira, M. d. M.

Publications and source records attributed to Teixeira, M. d. M..

3 recordsLinked to original sources

bioRxiv2026

Genome variation of Sporothrix schenckii and Sporothrix brasiliensis

Sporotrichosis, a subcutaneous mycosis caused by dimorphic fungi of the Sporothrix genus, has become a major zoonotic epidemic in South America, primarily driven by Sporothrix brasiliensis. To elucidate the genomic basis of its emergence and antifungal adaptation, we analyzed whole-genome sequences from 94 Sporothrix isolates, integrating single-nucleotide polymorphism (SNP), copy number variation (CNV), and genome-wide association (GWAS) analyses. Comparative genomics revealed 610,242 SNPs within S. brasiliensis and 1,474,627 within S. schenckii, confirming a marked disparity in intraspecific diversity. Phylogenomic tree inference resolved six well-supported S. brasiliensis clades with limited internal divergence, reflecting recent population expansion, while S. schenckii displayed deep phylogeographic structure separating North and South American lineages. CNV profiling identified 158 affected genes in S. brasiliensis (60 gains, 98 losses) and 88 in S. schenckii (54 gains, 34 losses), concentrated near sub-telomeric regions. In S. brasiliensis, gains were enriched for kinases and intracellular trafficking functions, whereas losses involved genes related to translation and primary metabolism, suggesting regulatory reinforcement coupled with metabolic streamlining. A GWAS of itraconazole resistance identified 81 SNPs distributed across multiple scaffolds, with many located within genes related with transport, signaling, and redox balance, supporting a polygenic basis for azole response. Together, these results highlight distinct evolutionary strategies of closely related Sporothrix species and delineate the genomic changes associated with the emergence and drug tolerance of S. brasiliensis.

genomics↗

bioRxiv2025

Telomeric assemblies of Paracoccidioides genomes

Paracoccidioides is a genus of dimorphic fungal pathogens endemic to Latin America. We generated long-read de novo assemblies for 11 isolates representing four species of the brasiliensis complex (P. brasiliensis, P. americana, P. restrepiensis, P. venezuelensis) and P. lutzii. These include the first complete telomere-to-telomere assemblies for P. brasiliensis (Pb18) and P. americana (Pb03), each with five chromosomes. Comparative analyses revealed chromosomal fusion and fission events distinguishing P. brasiliensis and P. americana, and a 90 kb tandem duplication in P. americana containing siderophore biosynthesis genes (sid1, sid3, sid4), a cluster of putative virulence factors. Mitochondrial genomes showed conserved gene order but a phylogenetic topology inconsistent with the nuclear tree, suggesting mitochondrial introgression between P. lutzii and P. venezuelensis. RNA transposable elements were enriched near telomeres, correlated with genome size, and most abundant in P. lutzii. These assemblies provide key resources for understanding genome evolution and introgression in Paracoccidioides. SIGNIFICANCESpecies of Paracoccidioides cause paracoccidioidomycosis, a systemic mycosis that remains a major public health problem in Latin America. Despite their clinical importance, genome evolution across the genus is poorly understood owing to the lack of complete reference assemblies. Here, we present the first telomere-to-telomere reference genomes for P. brasiliensis and P. americana, enabling a comprehensive comparison of chromosomal structure across the genus. Our analyses reveal that the nuclear genome is highly dynamic and shaped by large-scale rearrangements and structural variants, including the duplication of a siderophore biosynthesis-related gene cluster linked to virulence. In contrast, the mitochondrial genome is structurally conserved but shows introgression between species, revealing hidden evolutionary exchange. Together, these genomic resources redefine our understanding of Paracoccidioides evolution and provide a foundation for advances in molecular diagnostics, epidemiological surveillance, and studies of fungal pathogenicity.

microbiology↗

bioRxiv2025

Mapping Histoplasma in Bats and Cave Ecosystems: Evidence from Midwestern Brazil

Caves serve as natural reservoirs for diverse microbial species due to their unique biotic and abiotic conditions. Histoplasma spp. is frequently associated with guano-enriched soil, low luminosity, and high humidity, particularly in Latin America, a region highly endemic for histoplasmosis. Despite the continents diverse biomes, local environmental and host distributions of Histoplasma remain poorly understood. To address this knowledge gap, we conducted a Histoplasma-specific quantitative PCR (qPCR) assay targeting the hc100 gene on guano samples from seven bat-inhabited caves and tissue samples from 74 bats of nine species in the Federal District of Brazil and surround-ing regions. We detected Histoplasma DNA in 16 of 80 soil samples (20%) and in 33 bats representing seven species. Among 222 tissue samples (74 lung, 74 spleen, 74 brain), 39 tested positive: 22 lung, 10 spleen, and 7 brain samples. Four bats had Histoplasma DNA in both lung and brain, and two in both lung and spleen. By mapping the presence of Histoplasma across sampled caves, we identified environmental hotspots of fungal prevalence, emphasizing the need for targeted surveillance. ImportanceOur study provides critical insights into the environmental and host distribution of Histoplasma spp. in Brazil, identifying caves with high fungal prevalence and demonstrating its presence in multiple bat species. These findings underscore the necessity of public health interventions to mitigate the risk of histoplasmosis among cave visitors in the region. Additionally, we highlight the utility of qPCR for detecting Histoplasma in environmental and biological samples, supporting future epidemiological research in Latin America.

microbiology↗