Department: Integrative Biology

Advisor: Dr. Douglas Fudge

Education:
M.Sc. candidate, Integrative Biology, University of Guelph (current)
B.Sc. Hons Zoology, University of Guelph (2009)

Research: Mechanisms of swelling and rupture in hagfish slime mucin vesicles

The focus of my research is to determine how the mucus component of hagfish slime is deployed when it contacts seawater. In the gland mucus cell of a hagfish, mucins (a type of glycoprotein) are packaged into relatively large vesicles, which are released into the external environment via holocrine secretion when the hagfish is disturbed. When these intact vesicles contact seawater, they swell and rupture almost instantaneously, releasing the mucins so that they can interact with a fibrous component (thread skeins) of hagfish slime, which is also released by the slime gland. It is thought that mucin vesicles also rupture when exposed to solutions of mono- and multivalent cations, and monovalent anions, however, it appears as though some portion of the vesicles require that calcium be present in order for rupture to occur.

I hypothesize that mucin vesicle rupture is mediated by the presence of ion channels in the vesicle membrane, and, furthermore, that this process is dependent on the presence of calcium ions specifically. I am seeking to determine whether the partial dependence on calcium ions indicates that there are two types of mucin vesicle, and I am also testing whether the rupture process is mediated by the presence of aquaporins in the membrane. Using slime collected from Pacific hagfish (Eptatretus stoutii), I am running mucin vesicle rupture assays in the presence of ion channel and aquaporin inhibitors in order to test for the presence of chloride, sodium, and calcium ion channels in the vesicle membrane, and to determine which of these channels are important for mucin vesicle rupture.


Contact information:
Email address:  jherr@uoguelph.ca