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Due to limitations on high-resolution strain tracking, selection dynamics during gut microbiota colonization and transmission between hosts remain mostly mysterious. Here, we introduced hundreds of barcoded Escherichia coli strains into germ-free mice and quantified strain-level dynamics and metagenomic changes. Mutations in genes involved in motility and metabolite utilization are reproducibly selected within days. Even with rapid selection, coprophagy enforced similar barcode distributions across co-housed mice. Whole-genome sequencing of hundreds of isolates revealed linked alleles that demonstrate between-host transmission. A population-genetics model predicts substantial fitness advantages for certain mutants and that migration accounted for ∼10% of the resident microbiota each day. Treatment with ciprofloxacin suggests interplay between selection and transmission. While initial colonization was mostly uniform, in two mice a bottleneck reduced diversity and selected for ciprofloxacin resistance in the absence of drug. These findings highlight the interplay between environmental transmission and rapid, deterministic selection during evolution of the intestinal microbiota.
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http://dx.doi.org/10.1016/j.chom.2021.08.003 | DOI Listing |
Reprod Biomed Online
May 2025
Materno-fetal and Obstetrics Research Unit, Department Woman-Mother-Child, University Hospital of Lausanne, Lausanne, Switzerland; Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland. Electronic address:
Research Question: What is the composition of bacterial communities at various genital sites and are there potential interactions between partners' microbiota?
Design: This observational study involved metagenomic analyses of samples collected from male and female partners of couples undergoing fertility treatment. Samples included vaginal and penile swabs, as well as follicular fluid and semen, which were analysed using next-generation sequencing.
Results: The bacterial community profiles of different genital tract niches were distinct, niche-specific compositions, with female samples predominantly featuring Lactobacillus species and male samples displaying greater microbial diversity, including genital-specific and skin-associated taxa.
J Infect Public Health
September 2025
Department of Nursing, College of Nursing and Health Sciences, Jazan University, Jazan 82911, Saudi Arabia; School of Medicine, Universidad Espiritu Santo, Samborondon 091952, Ecuador. Electronic address:
Introduction: Hajj is the largest annual mass gathering in the world, attracting more than 2 million pilgrims from 184 countries. Adverse climatic conditions and close proximity of pilgrims during Hajj rituals create a facilitating environment for the transmission of infectious agents, including multi-drug resistant organisms. Although, several individual reports have been published on specific type of infections, there is a paucity of published work reflecting the overall picture of the prevalence of pathogenic infections during Hajj.
View Article and Find Full Text PDFBiochemistry
September 2025
Loyola University Chicago, Department of Chemistry and Biochemistry, 1068 W Sheridan Rd, Chicago, Illinois 60660, United States.
Dihydroorotate dehydrogenase 1B (DHOD1B) is one of several flavoproteins that utilize active half-sites. These enzymes have two flavin cofactors (FAD and FMN) that each interact with a specific reductant/oxidant substrate/product. Electrons gained at one-half-site must be transmitted to the other half-site and iron-sulfur centers between the flavin cofactors serve in this role.
View Article and Find Full Text PDFCell Rep
September 2025
Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. Electronic address:
The neural circuits that transmit the sense of pain and how pain is encoded by these circuits are still poorly understood.Mechanical allodynia is a prominent form of chronic pain characterized by painful responses to innocuous touch that develops as a consequence of nerve damage and inflammation. Here, we show that alterations to the normal log-normal distribution of neuronal activity and structure of neural correlations between neurons in the dorsal column nuclei (DCN) constitute a signature feature of mechanical allodynia, with the transmission of "allodynic" light touch information to the thalamus by somatostatin-positive projection neurons in the DCN being essential for its expression and development.
View Article and Find Full Text PDFFood Environ Virol
September 2025
REDOLí Research Group, Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat de Valencia, Valencia, Spain.
The global emergence of SARS-CoV-2 has highlighted the urgent need for effective disinfection strategies to mitigate virus transmission. Electrolyzed water (EW), an eco-friendly and cost-effective biocidal agent, has garnered attention for its broad-spectrum antimicrobial activity. This study evaluates the virucidal, bactericidal, and fungicidal capacities of EW with diverse pH, with a focus on its effectiveness against SARS-CoV-2 and other pathogens.
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