csi undergraduate conference on research, scholarship ... - CSI Today

Research Poster PresentationsP O S T E R 8 2Effect of Ps-tau on the OmmatidiaTransgenic DrosophilaJustin ChackoFaculty Mentor: Dr. Alejandra AlonsoDepartment of BiologyAlzheimer’s disease falls into a category with otherdiseases such as frontotemporal dementia withParkinsonism linked to chromosome-17 and Pick’sdisease called tauopathies. Tauopathies are causedby the abnormal hyperphosphorylation of themicrotubule associated protein tau. Tau binds toaxonal microtubules and helps provideorganization, stability and function. The abnormalhyperphosphorylation of tau is caused by enzymescalled kinases which phosphorylate specific serineand threonine residues. Phosphorylation causes theaddition of a negative phosphate group to theprotein causing conformational changes. Normaltau contains approximately 3 moles of phosphateper mole of protein, while hyperphosphorylatedtau contains approximately 7-10 moles ofphosphate per mole of protein. The conformationalchange bought on by this excess phosphorylationcauses the formation of filaments. Thephosphorylation of tau decreases it interactionwith microtubules and through in-vitro studies itwas shown that sites Thr212, Ser214, Thr231,Ser235 and Ser262 are major sites for inhibition oftau-microtubules binding. Through site-directedmutagenesis sites Thr212, Thr231 and Ser262 werechanged to a glutamic acid. The negative charge ofthe glutamic acid side chain can mimic the effect ofthe negative phosphate group inhyperphosphorylated tau. Transgenic fliescontaining this pseudophosphorylated tau werecreated and regulation of thepseudophosphorylated tau is controlled by a GAL4inducible system. The transgenic drosophilacontaining pseuophosphorylated tau allows thestudy of tau hyperphosphorylation in-vivo and themechanism of tau phosphorylation inducedtoxicity. The effect of tau toxicity caused by thepseudophosphorylated tau can be seen through theeffect of its expression on the eyes of transgenicdrosophila. The expression of the abnormal tau inthe drosophila eyes is examined using scanningelectron microscopy (SEM) which provides highresolution and magnification. This is optimal to seethe effect of pseudophosphorylated tau on theommatidia of drosophila eyes.P O S T E R 8 3Fabrication of PorousSuperhydrophobic SurfacesKristi Abbatemarco, Mark BarahmanFaculty Mentor: Dr. Alan LyonsDepartment of ChemistrySuperhydrophobic surfaces exhibit variousproperties that can be used to facilitate a broadrange of applications. Among these properties arelarge contact angles and decreased hydrodynamicdrag. Superhydrophobic surfaces are limited,however, by the maximum water pressuredifference that can be sustained at the air/waterinterface. Above this pressure, the liquid transitionsto a wetted, non-superhydrophobic state. Our lab isdeveloping a method to increase the stability ofsuperhydrophobic surfaces and maximize thepressure of water that can be supported. Wecounter the liquid pressure by introducing gaspressure from below the surface. A porous surfaceto support the superhydrophobic structures isnecessary to apply counter-pressure.In this poster we describe the fabrication ofsuperhydrophobic surfaces on porous fabricmeshes to create superhydrophobic membranesusing printing technologies. Fabric meshes ofdifferent types were evaluated based on materialcomposition as well as pore size. The pore sizeneeds be small enough to support printing whilelarge enough to be financially feasible. A robotic3D printer was used to dispense arrays ofpolydimethysiloxane features, which render thesurface superhydrophobic, by a previouslyestablished method. Several modifications to theprotocol were necessary as a result of the changein substrate. We used double-sided tape on a glassslide to flatten the substrate fabric and hold it inplace for printing. We will present specific changesto printing parameters and discuss patternsobserved, as well as approaches to increasingsurface stability.64