Date Approved

2013

Date Posted

5-23-2013

Degree Type

Campus Only Senior Honors Thesis

Department

Biology

First Advisor

Daniel Clemans

Abstract

The human gastrointestinal bacterial community is made up of billions of bacteria ranging from 1013-1014 bacteria/mi. Some bacteria are considered pro biotic because they are beneficial to the human host. Probiotic bacteria can assist in metabolism by producing essential vitamins that the host cannot produce on its own, such as vitamin K and B12 • Encapsulated Bacteroides thetaiotaomicron is beneficial to the host because it metabolizes complex glycans that can otherwise build up in the intestinal tract and negatively impact digestive health.

Bacteria coaggregation is key in biofilm fonnation which is advantageous for bacteria because it allows for communication, genetic exchange, protection from the environment. Coaggregation occurs when one bacterium possesses proteins on its outer surface that directly binds with ligands on the neighboring bacteria species. Ligands can be lipopolysaccharides, teichoic acids, peptidoglycan, proteins and various carbohydrate capsules that make up the outer surface of bacteria.

Our aim was to map out the specific coaggregation pattern of each of the different capsular types of B. thetaiotaomicron VPI-5482 with Lactobacillus rhamnosus ATCC 53103, Escherichia coli MG 1655, Eubacterium plexicaudatum ASF 492, Klebsiella pneumoniae IA565, Lactobacillus acidophi!us NCFM, and Clostridium sp. ASF 500.

We examined the level of coaggregation in buffer solutions, which ofthe bacteria have the putative adhesins, and the characterization of the ligands. By characterizing these interactions, we will have a better understanding of the coaggregation relationships between pro biotic B. thetaiotaomicron VPI-5482 and the bacteria of the human gastrointestinal tract.

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