Date of Submission

5-2026

Document Type

Thesis

Degree Name

Master of Science in Cellular and Molecular Biology

Department

Biology and Environmental Sciences

Advisor

Nikolas M. Stasulli, Ph.D.

Committee Member

Anthony Melillo, M.S.

Committee Member

Anna Kloc, Ph.D.

Keywords

Serratia Marcescens, Heat Shock Response, Transcriptome, Nanopore Sequencing, Gene Expression, Virulence

MeSH

Serratia marcescens, Heat-Shock Response, Transcriptome, Nanopore Sequencing, Gene Expression Regulation, Bacterial, Virulence

LCSH

Serratia marcescens, Heat shock proteins, Gene expression, Nucleotide sequence, Gene expression, Virulence (Microbiology)--Genetic aspects

Abstract

Serratia marcescens acts as an opportunistic pathogen in humans, plants, and animals (8, 13, 15, 22, 25). Its pathogenicity is predicted to be made stronger by its enhanced ability to adapt to stress. Heat is a common stressor for bacteria in both clinical and environmental settings (31). Further knowledge into the full transcriptomic effects of the heat shock response can enhance the understanding of the link between pathogenicity and adaptation to stress. To investigate this, a time course was created to capture the transcriptome at different stages of the heat shock response. The bacteria was grown at 30°C before being shifted to 42°C. RNA was extracted from the control group at 30°C and then at 5 minutes, 20 minutes, and 60 minutes after the temperature shift. RNA was then purified before being synthesized into cDNA. Nanopore sequencing was utilized to sequence the cDNA. Analysis included differential gene expression calculations and a comparison of which genes were present or absent in each condition. Analysis showed that S. marcescens responds to stress with lowered transcription rates within minutes of its induction but doesn’t initiate a detectable heat shock response until 20 minutes, with the strongest response at 60 minutes. The 60 minute time point demonstrated increases in vital biological processes and in virulence-associated genes. This confirmed the production of a faster growing and more virulent culture as it began to adapt. This knowledge can be used to increase the ability to manage S. marcescens in its pathogenic form.

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Available for download on Monday, July 07, 2031

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