Characterization of the Salmonella enterica serotype Typhimurium fimbrial operons : a dissertation /
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[College Station, Tex.] :
[Texas A&M University System Health Science Center],
[2005]
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| Abstract: | ABSTRACT: The Salmonella enterica serotype Typhimurium (S. Typhimurium) genome contains 13 putative fimbrial operons termed agf(csg), fim, pef, lpf, bcf, saf, stb, stc, std, stf, sth, sti and stj. Evidence for in vitro expression of fimbrail proteins encoded by these operons is currently only available for agf, fim and pef. We raised antisera against putative major fimbrial subunits of S. Typhimurium, including AgfA, FimA, PefA, LpfA, BcfA, StbA, StcA, StdA, StfA, SthA and StiA. Elaboration of StcA on the bacterial surface could be detected by flow cytometry and immuno electron microscopy after expression of the cloned stcABCD operon from a heterologous T7 promoter in Escherichia coli. To study expression of fimbrial antigens in S. Typhimurium by flow cytometry we constructed individual strains carrying deletions in each of the fimbrial operons. Using these deletion mutants for gating, expression of fimbrial antigens was measured by flow cytometry in cultures grown in vitro or in samples recovered 8 hours after infection of bovine ligated ileal loops with S. Typhimurium. FimA was the only fimbrial antigen expressed by S. Typhimurium after static growth in Luria Bertani(LB) broth. Injection of static LB broth cultures of S. Typhimurium into bovine ligated ileal loops resulted in expression of BcfA, FimA, LpfA, PefA, StbA, StcA, StdA, StfA, and StiA. We also investigated the role of 11 serotype Typhimurium fimbrial proteins, including FimA, AgfA, BcfA, StbA, SthA, LpfA, PefA, StdA, StcA, StiA and StfA, as antigens during infection of genetically resistant mice (CBA). Infection of mice with serotype Typhimurium growth in broth culture resulted in seroconversion of animals to FimA, AgfA, BcfA, StbA, SthA, LpfA, PefA, StdA, StcA, StiA and StfA. Immunization of mice with glutathione-S-transferase (GST)-FimA, GST-AgfA, GST-BcfA, GST-StbA, GST-SthA, GST-LpfA, GST-PefA, GST-StdA, GST-StcA, GST-StiA and GST-StfA fusion proteins resulted in reduced fecal shedding of serotype Typhimurium during a challenge compared to a control group immunized with purified GST protein. Collectively, these data suggest that in vivo growth conditions drastically alter the repertoire of fimbrial antigens expressed by serotype Typhimurium and that expression of fimbrial antigens is induced during infection of mice. |
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| Item Description: | Vita. "Major Subject: Medical Sciences". "Submitted to the Graduate School of Biomedical Sciences of The Texas A&M University System Health Science Center in partial fulfillment for the requirements for the degree of Doctor of Philosophy May 2005." Approved as to style and content by: Andreas J. Bäumler, Renee M. Tsolis, James E. Samuel, L. Garry Adams, John M. Quarles. |
| Physical Description: | xi, 133 leaves : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references (leaves 121-130). |