Stevenson, Riki


Riki is in the Department of Chemistry and Biochemistry.  She joined the Training Program in 2011. Her research mentor is Dr. David Eisenberg.  She received a B.A. degree in 2006fromCSU Channel Islands.

Mentor: Dr. David Eisenberg

Research project:


Biofilms, a natural occurrence within many bacterial lifecycles, contribute significantly to antibiotic resistance, increased infection rates, nosocomial infections, microbially-influenced corrosion (MIC), biofouling and persistence under extreme environmental conditions. Recent research has shown multiple bacterial phyla utilize amyloid-based folding properties in cell surface adhesin proteins that are involved in the initial attachment phase of biofilm formation.  In the most well-researched example of a functional amyloid protein, curli in E.coli, sequences contributing significantly to amyloid fibrillation were narrowed down to specific tandem repeats.  Using a previously established computational method to predict short sequences likely to form steric-zipper based amyloid fibers, we have further reduced the curli segments necessary for analysis to a limited number of hexapeptides.  These hexapeptide segments will be assayed for fibrillation propensity by monitoring changes in thioflavin T (ThT) and congo red (CR) binding, electron microscopy (EM) fiber formation and an x-ray cross-b diffraction pattern distinctive for amyloid fibers. Solving targeted hexapeptide structures will facilitate inhibitors designed specifically to interrupt the nucleation-dependent protein assembly process of amyloid fibers.  Once biofilm formation is inhibited, bacteria will likely revert to their planktonic (free-floating) lifestyle and regain their original antimicrobial susceptibility.