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Virginia Tech

Regulatory Control of Brucella Genetic Transcription​

Abstract

dc:description.abstract

Brucella abortus is a causative agent of brucellosis, a chronic bacterial disease with global distribution. The pathogenesis of Brucella remains poorly understood, despite a century of study. During infection, the Brucella bacterium endures numerous environmental and host stresses but establishes a replicative niche in host cells. How the bacterium withstands these host stresses and establishes the replicative niche remains of intense interest. To approach these questions, this thesis probes multiple aspects of Brucella transcriptional regulation. Chapter 1 analyzes historical and current justifying the importance of the work to the Brucella field. Chapter 2 uses a mouse model of infection along with transcriptomics and traditional bacteriological assays to interrogate the quorum sensing system. Major findings include that the LuxR protein BabR contributes to Brucella survival, that 3-OXO-C12 is likely physiologically relevant to the bacterium, and that the quorum sensing system regulates denitrification. Chapter 3 describes a new method for identifying transcription factors controlling expression of regulatory small RNAs (sRNAs) and tests for validity of this method. Chapter 4 develops a screening method to identify the AHL synthesis pathway of Brucella. This pathway is unknown, but as we demonstrate in Chapter 2, controls the activity of the LuxR proteins VjbR and BabR, and thus the transcription of the downstream regulons. Finally, Chapter 5 summarizes several themes that emerged throughout the research in the previous chapters and then proposes several future research directions for Brucella biology.

Degree

thesis:*
Name thesis:degree_name
Doctor of Philosophy
Level thesis:degree_level
doctoral
Discipline thesis:degree_discipline
Biomedical and Veterinary Sciences
Department dc:contributor.department
Biomedical and Veterinary Sciences
Grantor dc:publisher
Virginia Tech
Year dc:date.issued
2025

Author and committee

dc:creator, dc:contributor.*
Author dc:creator
  • Caudill, Mitchell Tyler
Chair dc:contributor.committeechair
  • Caswell, Clayton Christopher
Committee members dc:contributor.committeemember
  • Allen, Irving C.
  • Lee, Margie Denise
  • Scharf, Birgit E.
  • Seleem, Mohamed Naguieb

Subjects

dc:subject × 4

Rights

dc:rights
Statement dc:rights
  • In Copyright
Language dc:language.iso
en

Identifiers

dc:identifier.*
Dc Identifier Other
vt_gsexam:42896
OAI identifier oai:identifier
oai:vtechworks.lib.vt.edu:10919/127261

Chain of custody

source
Harvested from
Virginia Tech
Base URL
vtechworks.lib.vt.edu/oai/request
Last updated
2026-07-22
Source record
OAI-PMH GetRecord
citation

Caudill, Mitchell Tyler. Regulatory Control of Brucella Genetic Transcription​. doctoral thesis, Virginia Tech, 2025. https://hdl.handle.net/10919/127261