Protective antigen component of B. anthracis toxin was produced and purified to the >99% level. Toxin was purified from culture supernatant utilizing concentration and liquid chromatography techniques. Purity was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified protective antigen retained biological and antigenic activity as evidenced respectively by lethality in Fischer 344 rats when injected in combination with lethal factor, and by positive results on the Ouchterlony double diffussion assay. Radioiodinated protective antigen was used both in the in vivo and the in vitro experiments. In vivo distribution of labelled protective antigen was determined in Fischer 344 rats. Assay of organ tissues for labelled protective antigen aided in the decision to use Maden-Darby bovine kidney cells for the cell cultures in the protective antigen binding studies. Protective antigen binding studies, all performed at 37°C, evaluated criteria for receptor existence. Labelled protective antigen was found to bind specifically and reversibly to Maden-Darby bovine kidney cells. Receptors proved to be saturable. Scatchard analysis showed a relatively high dissociation constant (KD= 17 X 10-9M) compared to other toxins in similar studies. This indicated moderately low affinity for protective antigen. The receptor was also partially characterized. It was shown that cholera toxin subunit B blocked the binding of labelled protective antigen to Maden-Darby bovine kidney cells and that the protective antigen receptor was insensitive to trypsin treatment. Both of these observations suggest a ganglioside as the receptor for protective antigen.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from PDF title page (viewed Feb. 4, 2010). Additional advisors: Subramaniam Ananthan, David E. Graves, Craig D. Smith, Sadanandan E. Velu. Includes bibliographical references.

Bacillus anthracis, the etiological agent of anthrax, is a spore- forming, toxin- producing bacterium. Currently, treatment of B. anthracis infections requires a 60- day antibiotic regimen. However, better therapeutics are required. Therefore, this study looked at the effect of levofloxacin and linezolid on B. anthracis cell viability, toxin production and spore formation using in vitro static models and a pharmacodynamic model. It was hypothesized that the combination would be the most effective at preventing toxin and spore production resulting in greater bacterial killing. However, these studies suggest otherwise. Nevertheless, clinically, the combination therapy may be more effective in rapid killing of vegetative B. anthracis and may be able to reduce the duration of therapy (by reducing the likelihood of spore survival). Therefore, the clinical benefit of combined therapy on long-term recurrence cannot be determined from these in vitro models. Further investigation with combination therapy is warranted. / October 2015

Alternative sigma factors play a key role in the physiology of Bacillus anthracis by regulating the transcription of the appropriate genes required for adaptation and survival. Under specific conditions, alternative sigma factors activate transcription by binding to the promoter of the genes relevant to the condition and initiate synthesis of RNA. Here we report that the transcription of predicted sigI gene in B. anthracis, BAS3231, is induced by elevated temperatures and involved in the regulation of virulence gene expression. We show that BAS3231 is required for cell viability at elevated temperatures. We have also demonstrated that mutation in the BAS3231 gene results in a decrease in virulence gene expression. Our study provides new insight into the role of alternative sigma factors in B. anthracis.

Thesis (Ph.D.)--Kent State University, 2007. / Title from PDF t.p. (viewed Nov. 21, 2007). Advisor: Christopher J. Woolverton. Keywords: Bacillus, spores, electron beam irradiation, anthrax, liquid crystals, detection. Includes bibliographical references.

Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. "August 2008" Includes bibliographical references.

Thesis(M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references.

Thesis (M.S.)--Brigham Young University. Dept. of Statistics, 2007. / Includes bibliographical references (p. 46-49).

Thesis (M.S.)--Miami University, Dept. of Chemistry and Biochemistry, 2008. / Title from first page of PDF document. Non-Latin script record Includes bibliographical references.

Regensburg, Univ., Diss., 2009.