Microbial Pathogenesis of Oral Organisms

Actinobacillus actinomycetemcomitans (Aa) is a gram-negative bacterium whose primary habitat in humans is the subgingival sulcus. The association between Aa and aggressive periodontitis in adolescents (e.g. localized juvenile penodontitis, LJP) provides the most compelling evidence for bacterial specificity in periodontitis. Fresh isolates with a "rough," adherent colony phenotype spontaneously and irreversibly switch to a non-adherent, smooth colony phenotype when grown in broth. The rough phenotype is primarily associated with numerous bundle-forming fimbriae on the cell surface. These fimbriae are encoded by a fimbrial operon (the flp operon) that has recently been identified in Aa. This operon likely influences phase variation, biofilm formation, and possibly leukotoxin association with the bacterial cell. 

The aims of this project are 1) to determine the molecular basis of fimbrial phase variation through the study of transcription, translation, and cell localization of Flp fimbrillin subunit, and 2) to perform functional analysis of potential promoter regions and to determine the transcriptional organization of the flp operon through the study of selected deletion mutants.

Other areas of Dr. Scannapieco's research are available at Relationship of Oral Pathogens to Systemic Diseases, Clinical & Translational Research, and Saliva and Salivary Glands