Demi's Work


Demi, a senior college student from the UC system participated in phagefinders for a while this summer.  Originally from Ghana, Demi was a pleasure to work with.  Demi's research was more advanced than the work the Phagefinders did.  This is the abstract that she composed regarding her summer research:


Isolation and Characterization of D29 Phage Resistant Mycobacterium smegmatis mutants

Demi Priscilla Letsa, William R. Jacobs Jr and Jordan Kriakov.*

Department of Microbiology and Immunology,

Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461

Department of Biological Sciences, California State University, Sacramento


Tuberculosis (TB) is a leading cause of death worldwide, accounting for 1.7 million deaths per year, especially in Third World countries. In recent years there has been a rise of TB cases due to HIV and multi-drug-resistant strains of the causative organism Mycobacterium tuberculosis. Research into M. tuberculosis pathogenesis remained slow and difficult until the recent development of genetic tools.

Mycobacteriophages, viruses that infect mycobacteria, played a key role in developing these genetic tools. While hundreds of mycobacteriophages have been identified, little work has been done to characterize the receptors these phages use to enter mycobacterial cells. We hypothesize that there are specific proteins or glycolipids that act as phage receptors. To characterize these receptors, we have isolated a battery of transposon mutants of mycobacteria that are resistant to phage D29 infection. The nature of these receptors was characterized by determining the site of the transposon insertion in the phage resistant mutants. Since D29 is found on M. tuberculosis, our analysis should lead to an improved understanding of the cell surface of this important pathogen.