The molecular basis of E. coli colonization of the intestinal tract will be investigated using a mouse model. The proposed research focuses on the nature of the molecular interactions which occur at the mucosal surface and the role of such interactions in colonization. The proposal consists of three parts. In part one, the role of bacterial motility, chemotaxis, and adhesion, in colonization of the large intestine will be investigated using mutants of normal human fecal E. coli and avirulent S. typhimurium. Two general categories of mutants will be employed. First, mutants of E. coli and S. typhimurium known to possess an impaired ability to colonize the large intestines of streptomycin-treated mice, relative to the parent strain, will be assayed for chemotaxis toward mucus and the ability to penetrate mucus in vitro. Second, mutants of E. coli and s. typhimurium will be selected for specific defects in motility, chemotaxis, adhesion to mucosal components, and ability to penetrate mucus in vitro, and the relative colonizing abilities of the mutants will be assessed in vivo. In part two, the receptors and bacterial adhesins responsible for in vitro adhesion to mucus and epithelial cell brush borders will be identified, purified and characterized. These studies include further characterization of the outer membrane adhesins of E. coli F-18, E. coli F-17, and S. typhimurium, and the respective cecal and colonic mucus and brush border receptors for these strains. In addition, the adhesive properties of a wide variety of nonpathogenic E. coli will be assessed for their ability to adhere to mucus and brush border receptors immobilized on polystyrene, and the receptors involve in adhesion will be separated and identified by means of gel filtration, SDS-PAGE, and Western blot analysis. In part three, the mucus and brush border receptors responsible for the adhesion of selected enterotoxigenic E. coli to the mucosal surface of the small intestine will be identified, characterized and compared. Additional experiments designed to examine the relationship between in vitro adhesion to specific receptors and in vivo colonization will be conducted. The overall objectives of the proposed research are to further characterize the interactions which occur at the mucosal surface, further investigate and characterize the components involved in these interactions, and clarify the role of such interactions in the bacterial colonization of the intestinal tract.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI016370-11
Application #
3126646
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Project Start
1980-09-01
Project End
1992-03-31
Budget Start
1990-09-01
Budget End
1992-03-31
Support Year
11
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Rhode Island
Department
Type
Schools of Arts and Sciences
DUNS #
135531015
City
Kingston
State
RI
Country
United States
Zip Code
02881
Utley, M; Franklin, D P; Krogfelt, K A et al. (1998) A Salmonella typhimurium mutant unable to utilize fatty acids and citrate is avirulent and immunogenic in mice. FEMS Microbiol Lett 163:129-34
Newman, J V; Burghoff, R L; Pallesen, L et al. (1994) Stimulation of Escherichia coli F-18Col- type-1 fimbriae synthesis by leuX. FEMS Microbiol Lett 122:281-7
McCormick, B A; Klemm, P; Krogfelt, K A et al. (1993) Escherichia coli F-18 phase locked 'on' for expression of type 1 fimbriae is a poor colonizer of the streptomycin-treated mouse large intestine. Microb Pathog 14:33-43
Burghoff, R L; Pallesen, L; Krogfelt, K A et al. (1993) Utilization of the mouse large intestine to select an Escherichia coli F-18 DNA sequence that enhances colonizing ability and stimulates synthesis of type 1 fimbriae. Infect Immun 61:1293-300
Krogfelt, K A; McCormick, B A; Burghoff, R L et al. (1991) Expression of Escherichia coli F-18 type 1 fimbriae in the streptomycin-treated mouse large intestine. Infect Immun 59:1567-8
Metcalfe, J W; Krogfelt, K A; Krivan, H C et al. (1991) Characterization and identification of a porcine small intestine mucus receptor for the K88ab fimbrial adhesin. Infect Immun 59:91-6
McCormick, B A; Laux, D C; Cohen, P S (1990) Neither motility nor chemotaxis plays a role in the ability of Escherichia coli F-18 to colonize the streptomycin-treated mouse large intestine. Infect Immun 58:2957-61
Cohen, P S; Kjelleberg, S; Laux, D C et al. (1990) Escherichia coli F-18 makes a streptomycin-treated mouse large intestine colonization factor when grown in nutrient broth containing glucose. Infect Immun 58:1471-2
Conway, P L; Welin, A; Cohen, P S (1990) Presence of K88-specific receptors in porcine ileal mucus is age dependent. Infect Immun 58:3178-82
Burghoff, R L; Laux, D C; Cohen, P S (1990) Construction of stable cloning vectors that do not segregate from a human fecal Escherichia coli strain in the streptomycin-treated mouse large intestine. Infect Immun 58:1141-5

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