Date Available

12-8-2012

Year of Publication

2012

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Arts and Sciences

Department/School/Program

Chemistry

First Advisor

Dr. Sylvia Daunert

Abstract

Quorum sensing enables bacteria to communicate with bacteria of the same or different species, and to modulate their behavior in a cell-density dependent manner. Communication occurs by means of small quorum sensing signaling molecules (QSMs) whose concentration is proportional to the population size. When a QSM threshold concentration is reached, certain genes are expressed, thus allowing control of several processes, such as, virulence factor production, antibiotic production, and biofilm formation. Not only many pathogenic bacteria are known to produce QSMs, but also QSMs have been identified in some bacteria-related disorders. Therefore, quantitative detection of QSMs present in clinical samples may be a useful tool in the investigation and monitoring of bacteria-related diseases, thus prompting the use of QSMs as biomarkers of disease. Herein, we have developed and utilized whole-cell biosensing systems and protein based biosensing systems to detect QSMs in clinical samples, such as, saliva, stool, and bowel secretions. Additionally, since bacteria are responsible for food spoilage, we employed the developed biosensing systems to detect QSMs in food samples and demonstrated their applicability for early identification of food contamination. Furthermore, we have utilized these biosensing systems to screen antibacterial compounds employed for food preservation, namely, generally regarded as safe (GRAS) compounds, for their effect on quorum sensing.

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