Karatan Lab

Characterization of the potABCD1 polyamine transport system in Vibrio cholerae

Vibrio cholerae is a gram negative, aquatic bacterium that resides in brackish waters, rivers, and estuaries.  The bacterium is the causative agent of the intestinal disease cholera.  Vibrio cholerae is able to thrive in both the natural and host environment by forming biofilms or aggregations of microorganisms that are able to adhere to many surfaces.  Biofilms can be influenced by many factors within the environment. In our lab we focus on the effects of polyamines especially norspermidine and spermidine on biofilm formation.  Polyamines are polycationic molecules with a hydrocarbon backbone and multiple amine groups. Polyamines regulate a number of cellular processes and are necessary for normal cell growth in both prokaryotes and eukaryotes.  While there have been extensive studies on the polyamine uptake systems in the bacterium Escherichia coli, not much is known about the uptake system in Vibrio cholerae. 

            My research focuses on characterizing the putative polyamine transport system in Vibrio cholerae, potABCD2D1.  Because this transport system is able to transport both spermidine and norspermidine I have been performing competition assays to determine if the system is preferential to a certain polyamine over the other by using high performance liquid chromatography.   In characterizing this system it is essential to look at all the proteins involved so I am currently in the process of making in frame deletions for all the proteins and then will assess the phenotypes to see if the rest of the system functions in transportation of polyamines.  I also am interested in genome analysis to see how common this system is among Vibrio species and other bacteria.