Biology subjects

Fresia, P.

Publications and source records attributed to Fresia, P..

5 recordsLinked to original sources

bioRxiv2026

Characterization of Ovine Abortion in Uruguay Reveals Extensive Non-Clonal Diversity and Multiple Evolutionary Origins of Toxoplasma gondii

Toxoplasma gondii is a globally prevalent zoonotic parasite with multiple life stages and transmission routes, including ingestion and transplacental transmission. It is a major cause of abortion in sheep, goats and pigs, among other production animals, worldwide. While Type II strains are common in livestock in North America and Europe, non-archetypal, non-clonal genotypes are highly prevalent in South America. This study aimed to determine the molecular epidemiology of T. gondii strains causing sheep abortion in Uruguay. Phylogenomic analyses confirmed significant divergence among typed strains and revealed similarities with genotypes previously detected in the human population. Two novel strains, were isolated and characterized, uncovering the connection between their genetic makeup and phenotypes. Differences in virulence could be correlated to differences in gene copy number of the pseudo kinase ROP5 - further highlighting this virulence factor as relevant in wild strains. Whole-genome sequencing further confirmed the divergence among Uruguayan isolates, uncovering at least three distinct evolutionary origins. Overall, our findings highlight the circulation of virulent non-clonal lineages with links to human infections and underscore the importance of furthering genomic surveillance in South America to better understand Toxoplasmas transmission dynamics, pathogenic potential, and zoonotic risk.

molecular biology↗

bioRxiv2024

Priestia megaterium ILBB592 based biofertilizer increases the efficiency of phosphorus fertilization, positively affects soybean nutrition and yield and modifies the rhizospheric bacterial community

Phosphorus (P) is needed by soybean plants to form vital molecules like ATP and nucleotides and perform plant functions like photosynthesis and Nitrogen biological fixation at nodules. Because P concentration in the soil solution is naturally low, P fertilization is applied to satisfy soybean requirements in high yielding crops. However, a small portion of added P is readily available to the plants, while most is retained by the soil matrix and eventually made available or lost through erosion and run-off to water bodies, where it promotes eutrophication. Therefore, technologies that enhance P uptake by crops could lead to lower P inputs and outputs from soybean cropping systems, improving sustainability. Priestia megaterium ILBB592 and Bacillus pumilus ILBB44 are two PGPR with P mobilization features that were single formulated as biofertilizers and co-inoculated with Bradyrhizobium elkanii on seeds of soybean Genesis 5602 in two consecutive years in the field, with and without P fertilization. Co-inoculation with ILBB592 improved plant P uptake, along with N and K, with and without P fertilization. Diversity was increased by co-inoculation with ILBB44 and ILBB592, and predicted genes related with P cycling in the rhizospheric soils were also augmented after co-inoculation with ILBB592, mostly with P fertilization. Shoot dry weight and yield were also improved although effect on yield was not statistically significant. P fertilization alone had no effect in the first year but showed some effect on nodules dry weight, P uptake and yield on the second year, suggesting a sufficient P level was obtained after repeated fertilizations. ILBB592 biofertilizer showed a positive effect on most plant parameters, including nodulation and P uptake in both years and both P fertilization regimes and is therefore considered as a useful technology to reduce P fertilization without jeopardizing plant performance.

microbiology↗

bioRxiv2023

Phenotypic and genomic characterization of Bacillus sensu lato for their biofertilization effect and plant growth promotion features in soybean plants

Bacillus sensu lato were screened for their capacity to mineralize organic phosphorus (P) and promote plant growth, improving nitrogen (N) and phosphorus nutrition of soybean plants. Isolates were first identified based on their genomic sequences through TYGS and ANII. ILBB95, ILBB510 and ILBB592 were identified as Priestia megaterium, ILBB139 as Bacillus wiedmannii, ILBB44 as a member of a sister clade of B. pumilus (together with a human pathogenic strain), ILBB15 as Peribacillus butanolivorans and ILBB64 as Lysinibacillus sp. These strains were evaluated for their capacity to mineralize organic P as sodium phytate and solubilize inorganic P forms in liquid medium. These in vitro assays allowed the strains to be ranked according to their P mobilization potential, with ILBB15 and ILBB64 showing the highest orthophosphate production from phytate, ILBB592 the lowest and ILBB510 nil. In addition, features related to their rhizocompetence and plant growth promotion were evaluated in vitro and in silico. Finally, plant bioassays were deployed to assess the effect of the co-inoculation of Bacillus s.l. strains and rhizobial inoculant on nodulation, plant growth and nutrition. In planta bioassays showed that B. pumilus ILBB44 and P. megaterium ILBB95 increased P absorbed in plants grown on a poor substrate of sand and vermiculite and also on the richer mix of sand, vermiculite and peat. Priestia megaterium ILBB592 increased rhizobial nodulation and N content in plants grown on sand, vermiculite and peat mixture only. ILBB15 reduced plant growth and nutrition on both substrates. Genomes of ILBB95 and ILBB592 were characterized by genes related with plant growth and biofertilization whereas ILBB15 was differentiated by genes related to bioremediation. Priestia megaterium ILBB592 can be described as nodule-enhancing rhizobacteria (NER) and together with ILBB95, can be envisaged as prospective PGPR with the capacity to exert a positive effect on N and P nutrition of soybean plants.

microbiology↗

bioRxiv2019

Pangenome analysis reveals genetic isolation in Campylobacter hyointestinalis subspecies adapted to different mammalian hosts

Campylobacter hyointestinalis is an emerging pathogen currently divided in two subspecies: C. hyointestinalis subsp. lawsonii which is restricted to pigs, and C. hyointestinalis subsp. hyointestinalis which can be found in a much wider range of mammalian hosts. Despite C. hyointestinalis has been reported as an emerging pathogen, its evolutionary and host-associated diversification patterns are still vastly unexplored. For this reason, we whole-genome sequenced 13 C. hyointestinalis subsp. hyointestinalis strains and performed a comprehensive comparative analysis including publicly available genomes of C. hyointestinalis subsp. hyointestinalis and C. hyointestinalis subsp. lawsonii to gain insight into the genomic variation of these differentially-adapted subspecies. Both subspecies are distinct phylogenetic lineages which present a barrier to homologous recombination, suggesting genetic isolation. This is further supported by accessory gene patterns that recapitulate the core genome phylogeny. Additionally, C. hyointestinalis subsp. hyointestinalis presents a bigger and more diverse accessory genome, which probably reflects its capacity to colonize different mammalian hosts unlike C. hyointestinalis subsp. lawsonii that is host-restricted. This greater plasticity in the accessory genome of C. hyointestinalis subsp. hyointestinalis correlates to a higher incidence of genome-wide recombination events, that may be the underlying mechanism driving its diversification. Concordantly, both subspecies present distinct patterns of gene families involved in genome plasticity and DNA repair like CRISPR-associated proteins and restriction-modification systems. Together, our results provide an overview of the genetic mechanisms shaping the genomes of C. hyointestinalis subspecies, contributing to understand the biology of Campylobacter species that are increasingly found as emerging pathogens.

genomics↗

bioRxiv2018

City-wide metagenomics uncover antibiotic resistance reservoirs in urban beach and sewage waters

BackgroundMicrobial communities present in environmental waters constitute a reservoir for antibiotic-resistant pathogens that impact human health. For this reason a diverse variety of water environments are being analyzed using metagenomics to uncover public health threats. However, the composition of these communities along the coastal environment of a whole city where sewage and beach waters are mixed, is poorly understood.\n\nResultsWe shotgun-sequenced 20 coastal areas from the city of Montevideo (capital of Uruguay) including beach and sewage water samples to characterize bacterial communities and their virulence and antibiotic resistance repertories. We found that sewage and beach environments presented significantly different bacterial communities. Sewage waters harbored a higher prevalence and a more diverse repertory of virulence and antibiotic resistant genes mainly from well-known enterobacteria, including carbapenemases and extended-spectrum betalactamases reported in hospital infections in Montevideo. Additionally, we were able to genotype the presence of both globally-disseminated pathogenic clones as well as emerging antibiotic-resistant bacteria in sewage waters.\n\nConclusionsOur study represents the first in using metagenomics to jointly analyze beaches and the sewage system from an entire city, allowing us to characterize antibiotic-resistant pathogens circulating in urban waters. The data generated in this initial study represent a baseline metagenomic exploration to guide future longitudinal (time-wise) studies, whose systematic implementation will provide useful epidemiological information to improve public health surveillance.

genomics↗