Characterization of an iron uptake system from uropathogenic Escherichia coli
department or school: Science, Faculty of
department or school: Microbiology and Immunology, Department of
data provider: DSpace
degree campus: UBCV
creator: Santamaría Amorocho, Valentina
issued: 2025-06-23T21:18:47Z
issued: 2025
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: In the context of infection, a challenge for pathogenic bacteria is to maintain iron homeostasis with varying iron availability due to changes in pH, oxygen concentration, and host nutritional immunity. Organisms such as Campylobacter jejuni and uropathogenic Escherichia coli (UPEC) strains use the Fet system to acquire iron and overcome these changes. In C. jejuni, the Fet system is composed of eight genes (fetMP-fetABCDEH). In both species, FetM and FetP interact and are proposed to uptake ferric and ferrous iron. The role of fetABCDEH in iron uptake or as a mechanism to overcome stress has not been characterized in UPEC and is still not well understood. The iron/manganese-deficient strain ECA458 (ΔentC ΔfecABCDE ΔfeoABC ΔmntH) was engineered to characterize the Fet system in a gain-of-function model. Using the chassis-independent recombinase-assisted genome engineering (CRAGE) system, fetMP, fetMP-fetABCDEH and fetAH were integrated into the genome of ECA458. The resulting strains (ECA-fetMP, ECA-fetMH, ECA-fetAH) were used for phenotypic characterization of the Fet system with E. coli K-12 W3110 (WT), ECA458 and ECA-LP (ECA458 with a landing pad in fliK) as controls. Growth on LB and iron-limited LB, response to oxidative and nitrosative stress, and tolerance to streptomycin were assessed for these strains. Strains ECA458 and ECA-LP had similar phenotypes such as limited growth, increased oxidative stress sensitivity and streptomycin tolerance compared to WT. The gain-of-function approach validated the role of FetMP in growth enhancement under iron restriction, increased sensitivity to oxidative stress and streptomycin compared to ECA458. The phenotypes for strains expected to express fetMP-fetABCDEH and fetABCDEH were similar to those seen in ECA458 and ECA-LP. In these strains, the expression of the fet genes in this model may be limited by unknown factors and further studies are required to define expression of fet genes by strains ECA-fetMH and ECA-fetAH. Th…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/91409
note: Characterization of an iron uptake system from uropathogenic Escherichia coli by Valentina Santamaría Amorocho B.Sc., Pontificia Universidad Javeriana, 2022 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Microbiology and Immunology) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) May 2025 © Valentina Santamaría Amorocho, 2025 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: Characterization of an iron uptake system from uropathogenic Escherichia coli submitted by Valentina Santamaría Amorocho in partial fulfilment of the requirements for the degree of Master of Science in Microbiology and Immunology Examining Committee: Dr. Michael Murphy, Professor, Department Head, Microbiology and Immunology, UBC Supervisor Dr. James Kronstad, Professor, Microbiology and Immunology, UBC Supervisory Committee Member Dr. Elitza Tocheva, Professor, Microbiology and Immunology, UBC Supervisory Committee Member Dr. Thomas Beatty, Professor, Microbiology and Immunology, UBC Additional Examiner iii Abstract In the context of infection, a challenge for pathogenic bacteria is to maintain iron homeostasis with varying iron availability due to changes in pH, oxygen concentration, and host nutritional immunity. Organisms such as Campylobacter jejuni and uropathogenic Escherichia coli (UPEC) strains use the Fet system to acquire iron and overcome these changes. In C. jejuni, the Fet system is composed of eight genes (fetMP-fetABCDEH). In both species, FetM and FetP interact and are proposed to uptake ferric and ferrous iron. The role of fetABCDEH in iron uptake or as a mechanism to overcome stress has not been characterized in UPEC and is still not well understood. The iron/manganese-deficient strain ECA458 (ΔentC ΔfecABCDE ΔfeoABC ΔmntH) was engineered to characterize the Fet syst…
has type: Thesis/Dissertation
date issued: 2025-11
is shown at: 10.14288/1.0449175
language: eng
degree discipline: Microbiology and Immunology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Murphy, Michael E. P.
type: Text
identifier URI: http://hdl.handle.net/2429/91409