Digitized Honors Theses (2002-2017)

Date of Award

5-10-2003

Document Type

Undergraduate Thesis

Degree Name

BSBA

Department

Biology

Faculty Mentor

Stephen Ballard

Advisor(s)

Anne Boettcher Ph.D., Charles Brockhouse Ph.D., Kelly Major Ph.D., Jack O'Brien Ph.D., Tim Sherman Ph.D.

Abstract

Persistent bacterial infections play a key role in the pathogenesis of cystic fibrosis (CF) lung disease. These infections lead to prolonged inflammatory responses that eventually result in lung degeneration and loss of pulmonary function. Unfortunately, it is currently unclear why CF airways show unusual susceptibility to bacterial colonization. Both normal and CF airway epithelia produce several antimicrobial factors that are thought to aid in preventing infection including Iactoferrin, lysozyme and P-defensins. Most of these substances are produced by submucosal glands. We reasoned that impaired liquid secretion from airway glands, which occurs in CF, might reduce delivery and effectiveness of these agents to the airway surface. In the present study, we sought to develop an assay to directly assess the bacteriocidal properties of porcine airway fluid. A modified radial diffusion assay was developed to measure the microbiocidal properties of test solutions against Pseudomonas aeruginosa, a common pathogen in CF airways.

Magainin II amide, a peptide with known antimicrobial properties, isolated from amphibian skin, demonstrated effective antimicrobial activity against P. aeruginosa in our assay. In addition, airway lavage fluid collected from pigs appeared to have measurable antibacterial activity when collection conditions were modified to optimize these properties (e.g. concentrating specific proteins of interest, removing other proteins that may interfere with antibacterial activity). Future studies will focus on defining and characterizing component proteins in those samples demonstrating bactericidal activity and applying this knowledge to understand the mechanisms of antimicrobial peptide secretions in vivo.

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