Date of Completion

12-2-2019

Embargo Period

12-2-2019

Keywords

Hawaiian bobtail squid; Euprymna scolopes; secondary metabolites

Major Advisor

Dr. Marcy Balunas

Associate Advisor

Dr. Spencer Nyholm

Associate Advisor

Dr. Kyle Hadden

Associate Advisor

Dr. Mark Peczuh

Associate Advisor

Dr. David Grant

Field of Study

Pharmaceutical Science

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

A beneficial host-microbe symbiosis that has been extensively studied is the association of the Hawaiian bobtail squid, Euprymna scolopes, with the bioluminescent bacterium Vibrio fischeri in the squid light organ. Our research used the Hawaiian bobtail squid as a model system to begin investigating the functional role of secondary metabolites associated with the accessory nidamental gland (ANG), a reproductive organ present in sexually mature female cephalopods, and jelly coat (JC) bacteria. Using this model organism, prior research supports that bacteria from the ANG are deposited into the egg JC. Subsequently, the JC bacteria produce compounds as a chemical defense mechanism during their physically unprotected embryonic period. A suite of analytical chemistry techniques (e.g. tandem mass spectrometry, direct analysis in real time mass spectrometry, liquid chromatography mass spectrometry, nuclear magnetic resonance) has been utilized to perform extensive chemical profiling of ANG and JC bacteria. In addition, ANG and JC bacterial extracts tested in biological assays demonstrate potent inhibition against various pathogens including Vibrio spp., Fusarium keratoplasticum, and Candida albicans. This research investigates chemical defense mechanisms utilized within these symbiotic systems, including the influence of the host environment on the production of chemical compounds by bacterial symbionts. We have shown that the ANG and JC bacteria produce antimicrobial compounds, providing some insight into the possible function of the ANG.

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