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THE UTILIZATION OF IMPORTANT DERIVATIVES (TMA & THIOTAURINE) OF
EUKARYOTIC OSMOLYTES BY NOVEL STRAINS OF EUBACTERIA
by
Beverly Elizabeth Flood
___________________________________
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(BIOLOGY)
December 2010
Copyright 2010 Beverly Elizabeth Flood
Object Description
| Title | The utilization of important derivatives (TMA & thiotaurine) of eukaryotic osmolytes by novel strains of Eubacteria |
| Author | Flood, Beverly Elizabeth |
| Author email | beverlyflood@mac.com; bflood@umn.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Biology |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2010-07-30 |
| Date submitted | 2010 |
| Restricted until | Restricted until 03 Sep. 2011. |
| Date published | 2011-09-03 |
| Advisor (committee chair) | Nealson, Kenneth H. |
| Advisor (committee member) |
Ziebis, Wiebke Fuhrman, Jed Alan Berelson, William M. |
| Abstract | This body of work concerns certain interactions between Eubacteria and animals investigated in two separate yet connected studies. The first study concerns microbial enrichments designed to promote methylotrophic growth on trimethylamine (TMA), an environmentally abundant degradation product of a number of Eukaryotic osmolytes, under anaerobic conditions by homoacetogens and sulfate-reducing bacteria (SRB) in salt marsh and estuarine sediments. Methanogens were eventually lost in the long-term enrichments due to the utilization of the inhibitor, 2-bromoethanesulfonic acid (BES). A combination of community profiling and comparative genomics revealed that members of both the SRB and the homoacetogens can probably grow on TMA. This study also resulted in the isolation of a coccoidal spirochete that is believed to homoacetogenic and methylotrophic, although additional studies are necessary for confirmation. This study also revealed that the inhibitor BES can be degraded by probably both SRB and dehalogenating bacteria. A strain of Gammaproteobacteria isolated in this study is the subject of the second study. This strain, tentatively named Thiotaurens thiomutagens, is closely-related to all known sulfur-oxidizing marine endosymbionts, especially symbionts of vestimentiferan tubeworms and lucinid clams. Like the endosymbionts, it possesses a branch sulfur-oxidation pathway, producing sulfur granules as an intermediate. The mechanism for the delivery of reduced sulfur to these endosymbionts is unknown. But the host animals are also known to synthesize high levels of the HS- scavenger hypotaurine, presumably to detoxify the cellular environment. The product of the HS- scavenging is thiotaurine, which is also found in high levels in the tissues that house the symbionts. This study determined that T. thiomutagens is capable of using thiotaurine as a HS- donor to fuel lithoautotrophic growth.; T. thiomutagens also demonstrated unusual mixotrophic and autotrophic growth patterns. Like many endosymbionts, it possesses only Form II RuBisCO for the Calvin Benson Basham carbon fixation pathway. In these symbioses, the host animal concentrates CO2 around the symbionts. T. thiomutagens is capable of carbon fixation under denitrifying conditions and under aerobic conditions, but only when provided elevated ratios of CO2 to O2. As such, T. thiomutagens may serve as an analogue for understanding endosymbiont physiology and possibly symbiont-host interactions. |
| Keyword | homoacetogen; sulfate-reducing bacteria; sulfide-oxidizing bacteria; thiotaurine; trimethylamine; 2-bromoethanesulfonic acid; hypotaurine; symbiosis; marine symbiosis; Thiotaurens thiomutagens; spirochete; osmolytes |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m3422 |
| Contributing entity | University of Southern California |
| Rights | Flood, Beverly Elizabeth |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@dots.usc.edu |
| Filename | etd-Flood-4026 |
| Archival file | uscthesesreloadpub_Volume29/etd-Flood-4026.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@dots.usc.edu |
| Full text | THE UTILIZATION OF IMPORTANT DERIVATIVES (TMA & THIOTAURINE) OF EUKARYOTIC OSMOLYTES BY NOVEL STRAINS OF EUBACTERIA by Beverly Elizabeth Flood ___________________________________ A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (BIOLOGY) December 2010 Copyright 2010 Beverly Elizabeth Flood |
