Exploring the role of mutations in the signal peptides of VIM-2, NDM-1, and IMP-1 in the development of advantageous phenotypes in Escherichia coli
department or school: Medicine, Faculty of
department or school: Biochemistry and Molecular Biology, Department of
data provider: DSpace
degree campus: UBCV
creator: Jun, Hee Jin
issued: 2021-04-27T16:58:47Z
issued: 2021
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Metallo-β-lactamases (MBLs) are powerful enzymes conferring antibiotic resistance to various pathogens. They are actively disseminated in a plethora of pathogenic organisms via horizontal gene transfer, and raise clinical concerns. Interestingly, a predominant number of pathogens that favor MBL expression belong to γ-proteobacteria such as Pseudomonas aeruginosa, implying biases in the host distribution. A previous study in the Tokuriki lab also revealed restricted MBL gene expression in phylogenetically distanced bacterial species. However, it is still obscure how the enzymes adapt to bacterial hosts. This thesis aims to understand mutations in the signal peptides of MBLs contributing to the adaptive phenotype development in Escherichia coli. A series of dose-response curve assays revealed a highly positive correlation between the sequenced individual variants and their respective population where a considerably narrow phenotypic diversity is observed. When the phenotypic diversity is in a limited range at a high ampicillin concentration, the variability in mutational effects associated with phenotypic variations may be confined by fitness costs, resulting in the development of similar phenotypes. This suggests that the sequence profiles of the variants are a reasonable representation of the mutational population. A bioinformatic analysis of the sequence profiles of NDM-1, VIM-2, and IMP-1 variants reveals that mutation-driven changes in translational steps are moderately correlated with minimum inhibitory concentration (MIC), implying that the mutations in the signal peptides are associated with adaptive phenotypes elevating MBL gene expression. In addition, I synthesized a new broad host range vector using three individual plasmid vectors by the Golden Gate assembly technique to analyze mutational effects of MBLs in Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas putida. The newly synthesized plasmid vector is compatible with th…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/77995
note: EXPLORING THE ROLE OF MUTATIONS IN THE SIGNAL PEPTIDES OF VIM-2, NDM-1, AND IMP-1 IN THE DEVELOPMENT OF ADVANTAGEOUS PHENOTYPES IN ESCHERICHIA COLI by Hee Jin Jun B.Sc., Simon Fraser University, 2014 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Biochemistry and Molecular Biology) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) April 2021 © Hee Jin Jun, 2021 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, a thesis entitled: Exploring the role of mutations in the signal peptides of VIM-2, NDM-1, and IMP-1 in the development of advantageous phenotypes in Escherichia coli submitted by Hee Jin Jun in partial fulfillment of the requirements for the degree of Master of Science in Biochemistry and Molecular Biology Examining Committee: Dr. Nobuhiko Tokuriki, Associate Professor, Biochemistry & Molecular Biology, UBC Supervisor Dr. Robert E. W. Hancock, Professor, Microbiology & Immunology, UBC Supervisory Committee Member Dr. Natalie Strynadka, Professor, Biochemistry & Molecular Biology, UBC Supervisory Committee Member Dr. Elitza Tocheva, Assistant Professor, Microbiology & Immunology, UBC Additional Examiner iii Abstract Metallo-β-lactamases (MBLs) are powerful enzymes conferring antibiotic resistance to various pathogens. They are actively disseminated in a plethora of pathogenic organisms via horizontal gene transfer, and raise clinical concerns. Interestingly, a predominant number of pathogens that favor MBL expression belong to 𝛾-proteobacteria such as Pseudomonas aeruginosa, implying biases in the host distribution. A previous study in the Tokuriki lab also revealed restricted MBL gene expression in phylogenetically distanced bacterial species. However, it is still obscure how the enzymes adapt to bacterial hosts. This thesis aims to understand mutations in the signal pept…
has type: Thesis/Dissertation
date issued: 2021-05
is shown at: 10.14288/1.0396977
language: eng
degree discipline: Biochemistry and Molecular Biology
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
type: Text
identifier URI: http://hdl.handle.net/2429/77995