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Genetic and environmental regulation...

Lawhon, Sara Dyann.

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Genetic and environmental regulation of virulence genes in Salmonella enterica serovar Typhimurium.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Genetic and environmental regulation of virulence genes in Salmonella enterica serovar Typhimurium./
Author:	Lawhon, Sara Dyann.
Description:	179 p.
Notes:	Source: Dissertation Abstracts International, Volume: 63-11, Section: B, page: 5067.
Contained By:	Dissertation Abstracts International63-11B.
Subject:	Biology, Molecular. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3071493
ISBN:	0493911898

Genetic and environmental regulation of virulence genes in Salmonella enterica serovar Typhimurium.
Lawhon, Sara Dyann.

Genetic and environmental regulation of virulence genes in Salmonella enterica serovar Typhimurium. - 179 p.

Source: Dissertation Abstracts International, Volume: 63-11, Section: B, page: 5067.

Thesis (Ph.D.)--North Carolina State University, 2003.

The purpose of this research has been to assess the effect of the genetic regulator, CsrA, and environmental conditions on the expression of virulence genes in <italic>Salmonella enterica</italic> serovar Typhimurium. CsrA is an RNA binding protein that alters messenger RNA stability in <italic>E. coli </italic> and regulates virulence genes located on the <italic>Salmonella </italic> pathogenicity island 1 (SPI-1). This work demonstrates that CsrA in <italic>S. typhimurium</italic> like its counterpart in <italic>E. coli </italic> regulates expression of genes required for flagellar synthesis and suggests a role for CsrA in the positive regulation of utilization of propanediol and ethanolamine, vitamin B12 synthesis, and expression of maltoporin, which transports maltose and maltodextrins across the bacterial cell membrane. Propanediol, ethanolamine, and maltodextrins are by-products of digestion likely present in the intestinal tract. Vitamin B12 is required for utilization of propanediol and ethanolamine. The sensor kinase BarA and its response regulator SirA control levels of CsrA indirectly through the expression of an untranslated RNA CsrB, which binds CsrA. SirA regulates expression of <italic>Salmonella</italic> virulence genes and is required for <italic> Salmonella</italic> enteropathogenesis. BarA and SirA have the opposite effects on propanediol and ethanolamine utilization, and vitamin B12 synthesis as CsrA, thus supporting the model of indirect regulation of CsrA by BarA/SirA. In addition, the short chain fatty acids (SCFA) acetate, propionate, and butyrate are present in the ileum and colon at differing total concentrations and relative percentages. SCFAs representing the ileum and acetate alone are able to restore SPI-1 invasion gene expression to a <italic>barA</italic> mutant but not to a <italic>sirA</italic> mutant. Additionally, ileal SCFAs increase the expression of SPI-1 virulence genes required for invasion of epithelial cells and increase the expression of genes required for survival within epithelial cells and macrophages. SCFAs representing the colon decrease expression of genes required for epithelial cell invasion and decrease the expression of genes required for flagellar synthesis and maltose transport while increasing the expression of genes required for glycerol and propanediol metabolism.

ISBN: 0493911898Subjects--Topical Terms:

1017719
Biology, Molecular.

Genetic and environmental regulation of virulence genes in Salmonella enterica serovar Typhimurium.
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100 1 $a Lawhon, Sara Dyann. $3 1942974
245 1 0 $a Genetic and environmental regulation of virulence genes in Salmonella enterica serovar Typhimurium.
300 $a 179 p.
500 $a Source: Dissertation Abstracts International, Volume: 63-11, Section: B, page: 5067.
500 $a Directors: Craig Altier; Paul Orndorff.
502 $a Thesis (Ph.D.)--North Carolina State University, 2003.
520 $a The purpose of this research has been to assess the effect of the genetic regulator, CsrA, and environmental conditions on the expression of virulence genes in <italic>Salmonella enterica</italic> serovar Typhimurium. CsrA is an RNA binding protein that alters messenger RNA stability in <italic>E. coli </italic> and regulates virulence genes located on the <italic>Salmonella </italic> pathogenicity island 1 (SPI-1). This work demonstrates that CsrA in <italic>S. typhimurium</italic> like its counterpart in <italic>E. coli </italic> regulates expression of genes required for flagellar synthesis and suggests a role for CsrA in the positive regulation of utilization of propanediol and ethanolamine, vitamin B12 synthesis, and expression of maltoporin, which transports maltose and maltodextrins across the bacterial cell membrane. Propanediol, ethanolamine, and maltodextrins are by-products of digestion likely present in the intestinal tract. Vitamin B12 is required for utilization of propanediol and ethanolamine. The sensor kinase BarA and its response regulator SirA control levels of CsrA indirectly through the expression of an untranslated RNA CsrB, which binds CsrA. SirA regulates expression of <italic>Salmonella</italic> virulence genes and is required for <italic> Salmonella</italic> enteropathogenesis. BarA and SirA have the opposite effects on propanediol and ethanolamine utilization, and vitamin B12 synthesis as CsrA, thus supporting the model of indirect regulation of CsrA by BarA/SirA. In addition, the short chain fatty acids (SCFA) acetate, propionate, and butyrate are present in the ileum and colon at differing total concentrations and relative percentages. SCFAs representing the ileum and acetate alone are able to restore SPI-1 invasion gene expression to a <italic>barA</italic> mutant but not to a <italic>sirA</italic> mutant. Additionally, ileal SCFAs increase the expression of SPI-1 virulence genes required for invasion of epithelial cells and increase the expression of genes required for survival within epithelial cells and macrophages. SCFAs representing the colon decrease expression of genes required for epithelial cell invasion and decrease the expression of genes required for flagellar synthesis and maltose transport while increasing the expression of genes required for glycerol and propanediol metabolism.
590 $a School code: 0155.
650 4 $a Biology, Molecular. $3 1017719
650 4 $a Biology, Microbiology. $3 1017734
690 $a 0307
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710 2 0 $a North Carolina State University. $3 1018772
773 0 $t Dissertation Abstracts International $g 63-11B.
790 1 0 $a Altier, Craig, $e advisor
790 1 0 $a Orndorff, Paul, $e advisor
790 $a 0155
791 $a Ph.D.
792 $a 2003
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3071493