Biology subjects

Prado, M. B.

Publications and source records attributed to Prado, M. B..

3 recordsLinked to original sources

bioRxiv2022

A Longitudinal Study of Dominant E. coli Lineages and Antimicrobial Resistance in the Gut of Children Living in an Upper Middle-income Country

The gastrointestinal tract constitutes a complex and diverse ecosystem. Escherichia coli is one of the most frequently studied and characterized species in the gut ecosystem, nevertheless, there has been little research to determine their diversity and population dynamics in the intestines of children over time. In this prospective study, a fresh fecal sample was obtained from children longitudinally over one year (30 fecal samples at sampling period 1 and 22 fecal samples at sampling periods 2 and 3). From each stool sample, five E. coli colonies were randomly selected (n = 405 E. coli isolates total) in order to characterize the genotype and phenotypic antimicrobial resistance patterns. We found that all numerically dominant E. coli lineages in childrens intestines were transient colonizers, and antimicrobial resistance phenotypes of these strains varied significantly over time without any apparent selective force. Whole-genome sequencing of 3 isolates belonging to ST131 found in one child during the sampling period I and II indicated that isolates were three different ST 131 clones that carried extended-spectrum {beta}-lactamase (ESBL) genes. IMPORTANCEThe length of residency and numeric dominance of antimicrobial-resistant E. coli may affect the extent to which an isolate contributes to the dissemination of antimicrobial resistance in a community. We studied the persistence of numerically dominant and antimicrobial-resistant lineages of E. coli in the human intestine. We found that E. coli lineages in the children's gut change considerably and rapidly over time. This study suggests that some phenotypic resistance patterns may result from the random distribution of genes in E. coli populations over time and may not be associated with differential exposure to antimicrobials.

microbiology↗

bioRxiv2019

Evolutionary changes of an intestinal Lactobacillus reuteri during probiotic manufacture

Probiotic bacteria are frequently used to treat intestinal (and other types of diseases) or to improve health, however little is known about the evolutionary changes of these bacteria during probiotic manufacture. It has been observed that when bacteria adapt to a new environment, they lose the skills to thrive in the original niche. In this study, a strain of Lactobacillus reuteri was isolated from the duodenum of a mouse and subjected to 150 serial passes in milk to simulate industrial propagation of probiotic bacteria. The strain adapted to milk outperformed its ancestor in milk, but it showed reduced aptitude to grow culture media, and possibly in mouse intestines. Bacterial adaptation to milk seemed to select a number of non-synonymous mutations in metabolic genes.\n\nIMPORTANCEBacteria in the microbiota must endure hostile conditions including antagonism from other members of the microbial community. Little is known about the evolution of probiotic bacteria in the dairy industry. We show that repeated growth of L. reuteri in milk results in reduced ability to grow in culture medium and possibly colonize the mammalian intestine. Our results contribute to the notion that probiotic bacteria colonize only transiently intestines.

evolutionary biology↗

bioRxiv2018

A hypomorphic Stip1 allele reveals the requirement for chaperone networks in mouse development and aging

Chaperone networks are dysregulated with aging and neurodegenerative disease, but whether compromised Hsp70/Hsp90 chaperone function directly contributes to neuronal degeneration is unknown. Stress-inducible phosphoprotein-1 (STI1; STIP1; HOP) is a co-chaperone that simultaneously interacts with Hsp70 and Hsp90, but whose function in vivo remains poorly understood. To investigate the requirement of STI1-mediated regulation of the chaperone machinery in aging we combined analysis of a mouse line with a hypomorphic Stip1 allele, with a neuronal cell line lacking STI1 and in-depth analyses of chaperone genes in human datasets. Loss of STI1 function severely disturbed the Hsp70/Hsp90 machinery in vivo, and all client proteins tested and a subset of cochaperones presented decreased levels. Importantly, mice expressing a hypomorphic STI1 allele showed spontaneous age-dependent hippocampal neurodegeneration, with consequent spatial memory deficits. STI1 is a critical node for the chaperone network and it can contribute to age-dependent hippocampal neurodegeneration.

cell biology↗