Publication Date

2020

First Advisor

Christine A. White-Ziegler

Document Type

Honors Project

Degree Name

Bachelor of Arts

Department

Biochemistry

Keywords

Escherichia coli, Transcriptome, Proteome, Temperature, Pathogens

Abstract

When Escherichia coli (E. coli) infects a host, it is exposed to a severe temperature shift, going from ambient (23°C) to host temperature (37°C). In order to survive, both commensal and pathogenic E. coli have developed elaborate mechanisms to sense this environmental change and use it as an adaptation cue. While previous efforts in the laboratory focused on studying how a shift from ambient to host temperature affect the expression of the bacteria transcriptome, in the present study we have combined data from high throughput RNA sequencing with liquid-chromatography-coupled mass spectrometry (LC-MS) to uncover key pathways whose regulation changes on both the transcriptome and the proteome level in response to temperature. Commensal (MG1655), enteropathogenic (E2348/69) and uropathogenic (CFT073) strains were grown to a mid-exponential phase, whole cell extracts (n=5) were isolated and proteins were labeled using tandem mass tags (TMT). LC-MS was used to identify and quantify the proteins expressed by each strain, and those proteins which had a significant change in abundance between the two temperatures (as FC ≥ 2 and p-value < 0.05) were grouped into by molecular function. For each strain, we identified over 2000 proteins expressed in given conditions. Around 6% of all identified proteins of commensal strain, 5% of uropathogenic and 1.4% of enteropathogenic had significant changes in abundances between 37°C and 23°C, and were associated with attachment to host cells, nutrient uptake, immune system evasion, virulence and toxin release, energy production and other processes crucial for bacterial survival inside the host. Surprisingly, despite the high temperature regulation seen at both the transcriptome and the proteome level independently, the correlation between temperature regulated transcripts and corresponding proteins appeared lower, possibly hinting at the importance of processes such as post-transcriptional processing and translational regulation in fine tuning the response of E. coli to the outside environment.

Rights

©2020 Isidora Stankovic. Access limited to the Smith College community and other researchers while on campus. Smith College community members also may access from off-campus using a Smith College log-in. Other off-campus researchers may request a copy through Interlibrary Loan for personal use.

Language

English

Comments

v, 74 pages : color illustrations. Includes bibliographical references (pages 69-74)

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