| Descript |
186 p |
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Source: Dissertation Abstracts International, Volume: 66-08, Section: B, page: 4076 |
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Supervisor: Bradley D. Jones |
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Thesis (Ph.D.)--The University of Iowa, 2005 |
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Salmonella enterica serovar Typhimurium is a Gram-negative human pathogen that colonizes and invades the intestinal mucosa. We and others have demonstrated that S. Typhimurium attaches to and forms biofilm on eukaryotic cell surfaces in a type 1 fimbriae-dependent manner. To investigate the effect of biofilm on gene expression, we compared gene expression between planktonic and biofilm growth. Microarray results indicated that genes encoding products involved in antibiotic resistance, central metabolism, conjugation, intracellular survival, membrane transport, and fimbrial biosynthesis are significantly altered by growth in a biofilm. The identification of five fimbrial gene clusters was of particular interest because their roles in adherence and intercellular adherence. Mutations in the bovine colonization factor ( bcf), long polar (lpf), plasmid encoded ( pef), thin aggregative (csg), and Sth ( sth) fimbriae were constructed in S. Typhimurium and the mutants were found to have various biofilm phenotypes on plastic, HEp-2 cells and chicken intestinal tissue. The pef and csg mutants were defective for biofilm formation on each of the surfaces tested, while the lpf mutant exhibited a complete loss in ability to form biofilm on chicken intestinal tissue but only an intermediate loss of biofilm formation on HEp-2 cells and plastic. The bcf mutant formed increased biofilm on both HEp-2 cells and chicken intestinal epithelium while the sth mutant had no detectable biofilm defects |
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In addition, previous work on Salmonella exopolysaccharide in biofilm indicated that the EPS composition can vary based upon the substratum on which the bacterial biofilm forms. We have investigated the role of genes important in the production of colanic acid and cellulose, common components of EPS. A mutation in the colanic acid biosynthetic gene, wcaM, disrupted biofilm formation on HEp-2 cells and chicken intestinal tissue, although biofilm formation on plastic was unaffected. A mutation in the cellulose biosynthetic gene, yhjN, disrupted biofilm formation on HEp-2 cells, chicken intestinal epithelium, and on plastic. Our data indicate that Salmonella attachment to, and growth on, eukaryotic cells represent complex interactions that are facilitated by species of EPS and fimbriae. Understanding these interactions is likely to provide new insights for intervention strategies for Salmonella colonization and infection |
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School code: 0096 |
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DDC |
| Host Item |
Dissertation Abstracts International 66-08B
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| Subject |
Biology, Microbiology
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0410
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| Alt Author |
The University of Iowa
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