Research in the Whitney lab employs a multidisciplinary approach to uncover the molecular details of pathways that shape the composition of bacterial communities. Specific areas of research include interbacterial competition and bacterial adhesion.
Interbacterial Killing by the Type VI secretion system
The bacterial type VI secretion system is a recently identified protein translocation pathway used by Gram-negative bacteria to deliver toxins to neighbouring bacteria in a cell contact-dependent manner. We are interested in understanding how these antibacterial proteins are transported from one cell to another and how they exert toxicity once delivered to a target cell. By understanding the molecular principles underlying this process it is our long term goal to be able to rationally manipulate bacterial populations relevant to human health.
exopolysaccharide secretion and interbacterial adhesion
Many species of bacteria exist in dense cellular aggregates held together by bacterially produced exopolysaccharides. In this form, bacteria are difficult to eradicate due in part to decreased efficacy of antibiotics. We are interested in determining how bacterial exopolysaccharides are synthesized and exported from the cell. By understanding how this process occurs at the molecular level, we hope to one day be able to inhibit exopolysaccharide secretion under circumstances where it is detrimental to human activities (i.e. biofouling of pipes, colonization of indwelling medical devices, etc.).
Type VII secretion-dependent interBacterial Antagonism
In contrast to their Gram-negative counterparts, the identification of pathways involved in interbacterial antagonism between Gram-positive bacteria has long remained elusive. In recent work, we and others have found that the type VII secretion system exports antibacterial toxins that mediate interbacterial competition. Elucidating the mode of action of these toxins will allow for the identification of new vulnerabilities in Gram-positive cells that can be exploited for the development of new antibiotics.