Jonathan Spencer

Learn More
Fluorine is the thirteenth most abundant element in the earth's crust, but fluoride concentrations in surface water are low and fluorinated metabolites are extremely rare. The fluoride ion is a potent nucleophile in its desolvated state, but is tightly hydrated in water and effectively inert. Low availability and a lack of chemical reactivity have largely(More)
The main research question we explore in this dissertation is: How should a retailer modify its product assortment over time in order to maximize overall profits for a given selling season? Historically, long development, procurement, and production lead times have constrained fashion retailers to make supply and assortment decisions well in advance of the(More)
LC-MSn analysis of mycolactone toxin from extracts of Mycobacterium ulcerans has shown that minor co-metabolites, including two previously unreported, differ structurally from mycolactone only in a small portion of the polyketide side-chain.
The thioesterase FlK from the fluoroacetate-producing Streptomyces cattleya catalyzes the hydrolysis of fluoroacetyl-coenzyme A. This provides an effective self-defense mechanism, preventing any fluoroacetyl-coenzyme A formed from being further metabolized to 4-hydroxy-trans-aconitate, a lethal inhibitor of the tricarboxylic acid cycle. Remarkably, FlK does(More)
Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as(More)
This application, developed by students in service learning courses, will be used both by workers at the Red Cross to find and solicit volunteers and by volunteers who want to keep track of their volunteer-work history and Red Cross certifications. By capturing such knowledge in an easily accessible database, Red Cross workers can use our intuitive front(More)
(1999) Abnormal photoresponses and light-induced apoptosis in rods lacking rhodopsin kinase. (2001) Multiple phosphorylation of rhodopsin and the in vivo chemistry underlying rod photoreceptor dark adaptation. (2004). Visual pigment phosphorylation but not transducin translocation can contribute to light adaptation in zebrafish cones. (2005). Lightdependent(More)
  • 1