1.
Reynolds, Mollie Megan.
Identification of Novel Virulence Genes of Salmonella enterica Using an Array Based Analysis of Cistrons Under Selection.
Degree: PhD, Genetics, 2011, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7675 
Pools of mutants of minimal complexity but maximal coverage of genes of
interest facilitate screening for genes under selection in a particular environment. Prior to
this work, mutants were generated by random transposon insertions, which yielded
highly complex pools for in vivo studies. Recent advances in polymerase chain reaction
(PCR)-based mutagenesis in bacteria using the lambda red recombinase, as well as
whole genome sequencing, enable a more directed approach for the generation of
mutants. The lambda red approach was used to construct individual mutants in 1,023
Salmonella enterica serovar Typhimurium genes, including almost all genes found in
Salmonella, but not in related genera. All the mutations were confirmed simultaneously
using a novel amplification strategy to produce labeled ribonucleic acid (RNA) from a
T7 RNA polymerase promoter, introduced during the construction of each mutant,
followed by hybridization of this labeled RNA to a Typhimurium genome tiling array.
To demonstrate the ability to identify fitness phenotypes using our pool of mutants, the
pool was subjected to selection by intraperitoneal injection into BALB/c (Bagg Albino)
mice and was recovered from the spleen. Changes in the representation of each mutant were monitored using T7 transcripts hybridized to a novel inexpensive minimal
microarray. Among the top 120 statistically significant spleen colonization phenotypes,
51 were mutations in genes with no previously known role in this model. Fifteen
phenotypes were tested using individual mutants in competitive assays and eleven were
confirmed in individual mixed intraperitoneal infection in mice, including the first two
examples of attenuation for sRNA mutants in Salmonella. We refer to our method as
Array-Based Analysis of Cistrons Under Selection (ABACUS).
Among the confirmed mutants identified in the ABACUS screen was a
component of the twin arginine transport (Tat) system, tatC, required for transport of
folded proteins across the cellular membrane. TatC is the highly conserved component
necessary for recognition of the twin arginine containing signal sequence S/T-R-R-x-FL-
K. We confirmed [delta] tatC mutants are defective for colonization of the liver and spleen
in competitive infections with wild type ATCC14028 after intraperitoneal infection in
Salmonella- susceptible (BALB/c). We also found that [delta] tatC mutants were defective for
swimming motility, but not swarming motility, which was linked to the ability to
elaborate flagellins on the bacterial surface under different conditions.
Advisors/Committee Members: Andrews-Polymenis, Helene L. (committee member), Adams, Garry (committee member), Samuel, James (committee member), Skare, Jonathon (committee member).Subjects/Keywords: ABACUS; Salmonella; genetic screens; Twin arginine transport; motility
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Reynolds, M. M. (2011). Identification of Novel Virulence Genes of Salmonella enterica Using an Array Based Analysis of Cistrons Under Selection. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7675
Chicago Manual of Style (16th Edition):
Reynolds, Mollie Megan. “Identification of Novel Virulence Genes of Salmonella enterica Using an Array Based Analysis of Cistrons Under Selection.” 2011. Doctoral Dissertation, Texas A&M University. Accessed March 09, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7675.
MLA Handbook (7th Edition):
Reynolds, Mollie Megan. “Identification of Novel Virulence Genes of Salmonella enterica Using an Array Based Analysis of Cistrons Under Selection.” 2011. Web. 09 Mar 2021.
Vancouver:
Reynolds MM. Identification of Novel Virulence Genes of Salmonella enterica Using an Array Based Analysis of Cistrons Under Selection. [Internet] [Doctoral dissertation]. Texas A&M University; 2011. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7675.
Council of Science Editors:
Reynolds MM. Identification of Novel Virulence Genes of Salmonella enterica Using an Array Based Analysis of Cistrons Under Selection. [Doctoral Dissertation]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7675
Texas A&M University
2.
Sivula, Christine Patricia.
Comparison of cecal colonization of Salmonella enterica serotype Typhimurium in white leghorn chicks and Salmonella-resistant mice.
Degree: MS, Laboratory Animal Medicine, 2009, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2989
Salmonellosis is one of the most important bacterial food borne illnesses
worldwide. Among the many Salmonella serotypes, Typhimurium is the most
commonly implicated serotype in human disease in the United States. A major source of
infection for humans is consumption of chicken or egg products that have been
contaminated with S. Typhimurium. The breadth of knowledge regarding colonization
and persistence factors in the chicken is small when compared to our knowledge of
factors that are important for these processes in other species used in Salmonella
research, such as cattle and mice. Defining the factors important for these processes in
the chick is the first step in decreasing the transmission of Salmonella between animal
and human hosts.
In this work, we developed a chicken model to identify and study intestinal
colonization and persistence factors of Salmonella enterica serovar Typhimurium. We
studied the degree of enteric and systemic colonization of wild type S. Typhimurium
ATCC14028, one of the most widely studied Typhimurium isolates, in White Leghorn chicks and in Salmonella-resistant CBA/J mice during infection. Furthermore, we
determined the distribution of wild type S. Typhimurium and a SPI-1 mutant (invA)
during competitive infection in the cecum of 1-week-old chicks and 8-week-old mice.
Cell associated, intracellular and luminal distributions of these strains in the cecum were
analyzed as total counts in each compartment and also as a competitive index.
Localization of S. Typhimurium ATCC14028 and the role of SPI-1 in colonization are
well studied in murine models of infection, but comparative infection in chicks with the
same strain has not been undertaken previously.
We show that the cecal contents are the major site for recovery of S.
Typhimurium in the cecum of 1-week-old chicks and Salmonella-resistant mice. We
also show that while SPI-1 is important for successful infection in the murine model, it is
important only for cell association in the cecum of 1-week-old chicks. Finally, we found
that in chicks infected at 1 week of age, bacterial counts in the feces do not reflect those
seen in the cecum as they do in mice.
Advisors/Committee Members: Adams, L. Garry (advisor), Andrews-Polymenis, Helene L. (advisor), Ihrig, Melanie (committee member).Subjects/Keywords: Salmonella; cecum; SPI-1; chicks; mice
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Sivula, C. P. (2009). Comparison of cecal colonization of Salmonella enterica serotype Typhimurium in white leghorn chicks and Salmonella-resistant mice. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2989
Chicago Manual of Style (16th Edition):
Sivula, Christine Patricia. “Comparison of cecal colonization of Salmonella enterica serotype Typhimurium in white leghorn chicks and Salmonella-resistant mice.” 2009. Masters Thesis, Texas A&M University. Accessed March 09, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-2989.
MLA Handbook (7th Edition):
Sivula, Christine Patricia. “Comparison of cecal colonization of Salmonella enterica serotype Typhimurium in white leghorn chicks and Salmonella-resistant mice.” 2009. Web. 09 Mar 2021.
Vancouver:
Sivula CP. Comparison of cecal colonization of Salmonella enterica serotype Typhimurium in white leghorn chicks and Salmonella-resistant mice. [Internet] [Masters thesis]. Texas A&M University; 2009. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2989.
Council of Science Editors:
Sivula CP. Comparison of cecal colonization of Salmonella enterica serotype Typhimurium in white leghorn chicks and Salmonella-resistant mice. [Masters Thesis]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2989
Open Access Theses and Dissertations
