Boston Convention Center Marquis

Boston, MA  
March 27-APRIL 1, 2015

Boston Night Skyline from Wharf

For the past 15 years, the University of Delaware Howard Hughes Medical Institute’s (HHMI) Undergraduate Science Education Program has sent undergraduate students to the Experimental Biology Meetings to present their research. As part of this annual conference, the American Society for Biochemistry and Molecular Biology (ASBMB) sponsors its 19th Undergraduate Poster Competition in which 6 of the 9 attending UD students participated this year. Since 2001, students from the University have received more awards in this competition than students from any other college or university.  UDaily article.

The University of Delaware group included four faculty and 9 undergraduates.

From left to right: Gabe, Becky, Lauren, Brooke, Matt, Molly, Andre, Hannah, Tom (in back)
Prof. Hal White, Chem &Biochem
Prof. Dave Usher, Biol. Sci.
Prof. Seung Hong, Biol Sci
Prof. Gary Laverty, Biol Sci

Hannah Anderson
Andre Freligh
Matthew Fischer
Lauren Genova
Gabriel Gregorzak
Brooke Palus
Molly Peters
Rebecca Pollak
Thomas Rivas

University of Delaware students and their abstracts.

Hannah Anderson

Winner of an Honorable Mention Award in the ASBMB Undergraduate Poster Competition

Differential Effects of FAK and FGFR Inhibitors on Motility and Proliferation of L1-Positive versus L1-Negative Glioblastoma Cells

Hannah Anderson and Deni Galileo

Department of Biological Sciences, University of Delaware, Newark, DE 19716

Glioblastoma multiforme (GBM), a highly invasive astrocytoma, is the deadliest form of brain cancer.  Glioblastoma cells express the L1CAM cell adhesion protein (L1), which is cleaved at the cell surface and binds to both integrins and fibroblast growth factor receptors (FGFRs) in an autocrine/paracrine manner.  Focal adhesion kinase (FAK), which is activated by L1-integrin interactions, and FGFR are tyrosine kinases that initiate signaling cascades stimulating GBM motility and proliferation.  We hypothesized that inhibitors of FGFR and FAK would have differential effects on the motility and proliferation of T98G glioblastoma cells expressing L1 compared to those with attenuated L1 expression.  Short hairpin RNA delivered by a lentiviral vector was used to block L1 expression.  Cell motility was measured through quantitative time-lapse microscopy, and proliferation was measured by cell cycle analysis and quantified as the population of cells in S phase.  FAK inhibitor Y15 had a greater effect in L1-positive versus L1-negative cells on motility (-45.3% vs. -5.6%) and S phase population (-6.5% vs. -3.5%).  FAK inhibitor PF431396 also produced a greater reduction in motility (-57.2% vs. -15.4%) and S phase population (-11.7% vs. -6.2%) in L1-positive versus L1-negative cells.  An inhibitor of FGFR, PD173074, reduced motility (-37.8% vs. +2.3%) and S phase population (-8.6% vs. -0.4%) in L1-positive cells only.  We conclude that inhibitors of FAK and FGFR drastically decrease L1-stimulated motility and proliferation in glioblastoma cells, indicating that they have chemotherapeutic potential for GBM tumors expressing L1.  Research support was provided by the Delaware Governor’s Bioscience Fellowship and the Center for Advanced Technology.

Andre Freligh

Cooperation at the Molecular Level Affects Your Performance and Health

Andre Freligh and John R. Jungck
Department of Biolgical Sciences, University of Delware

Many biological macromolecules are composed of subunits that function synergistically due to cooperativity. I have generated a spreadsheet model of the Hill Equation for the Biological Excel Simulations and Tools for Exploratory Experiential Mathematics (ESTEEM) modules page: in order for users to interactively develop a sense of nonlinear behavior of such macromolecules.  This software is accessible to students and professors both nationally and internationally. Originally, the Hill equation represented the cooperative binding process of oxygen to hemoglobin molecules. Although Hill’s model is not precise for modeling all forms of biological cooperativity, it is accurate enough that it is frequently utilized to describe the cooperative behavior of enzymes. In the model the parameters of the Hill equation are adjustable so that students can monitor the effects of adjusting such parameters. Additional spreadsheets will incorporate real world data about the binding of oxygen to hemoglobin under various conditions, the binding of ligands to enzymes, and genetic repressors whose data also fit the Hill equation. Medically, this model is relevant to the cooperativity of hemoglobin during intense anaerobic physical activity and is important to understanding the development of drugs for treating diabetes, sickle cell anemia, and thalassemia.


Matthew Fischer

Determining the Genotype-Phenotype Relationship of atg18 Mutants
Matthew Fischer and Erica M. Selva
Department of Biological Sciences, University of Delaware, Newark, DE 19716

8J16 and 9E6 are two independent allelic point mutations in
Drosophila melanogaster autophagy-specific gene 18a (atg18a) located in introns three and four, respectively, of its 5 exon locus at 66B11. The atg188J16 and atg189E6 intronic mutations are not in sequences expected to disrupt transcript processing, yet these mutations cause pupal lethality and neurodegenerative phenotypes by an unknown molecular mechanism. The purpose of this research is to examine the genotype-phenotype relationship of atg188J16and atg189E6on neuronal maturation using the Drosophila eye as a model. RT-PCR analysis revealed no detectable effects on atg18 mRNA splicing in either mutant background. In adults, atg188J16 and atg189E6 homozygous mutant eyes are small and display a rough eye phenotype. To understand the basis of this phenotype, homozygous mutant larval imaginal eye discs were examined. ELAV, a pan neuronal marker, showed that photoreceptors differentiate normally, but those that differentiate early are being lost by apoptosis as determined by the increased cleaved caspase 3. These mutations also caused significant death at the morphogenetic furrow, which may result in a smaller pool of photoreceptor progenitors. Hence, autophagy may have roles in both photoreceptor differentiation and maintenance and its absence leads to apoptotic death. Senseless and Prospero expression showed that photoreceptors R8 and R7, respectively, are more refractory to apoptosis as these photoreceptors predominate near the optic stalk. This suggests autophagy is more important for the maintenance of photoreceptors R1, R2, R3 R4, R5 and R6 than R7 and R8. Acknowledgements given to the Howard Hughes Medical Institute and University of Delaware Undergraduate Research Program for financial support.

Lauren Genova

Investigating the Binding Affinity of Nod2 and Soluble Bacterial Cell Wall Dimers
Lauren Genova and Catherine Leimkuhler Grimes

Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716

The innate immune system is the body’s first line of defense against pathogens. The innate immune system is triggered by pathogen associated molecular patterns (PAMPs) that are recognized by pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs) and Nod-like receptors (NLRs). This research project focuses on providing a better understanding of how the innate immune system senses and responds to the presence of bacteria. Specifically, our group is interested in the relationship between the nucleotide-binding oligomerization domain-containing protein 2 (Nod2), an NLR protein found in the cytosol of mammalian host cells, and muramyl dipeptide (MDP), the smallest bacterial cell wall fragment known to elicit an immunological response. When Nod2 is mutated, the signaling pathway becomes disrupted and uncontrollable inflammation arises, leading to chronic inflammatory bowel disorders such as Crohn’s disease. To discover how to better treat these diseases, it is imperative to learn more about how Nod2 and MDP interact, a mechanism which is currently unknown. The Grimes Lab has previously shown that Nod2 binds to MDP in vitro; however, research suggests that a heightened immunological response may be elicited in a host if molecules containing multiple MDP’s are used, suggesting multivalency is at play. To test this hypothesis, a variety of novel MDP dimers were synthesized to be assessed via in vitro SPR binding assays, as well as through cell-based assays.


Gabriel Gregorzak

Fueling the Interdisciplinary Flame: Exploring Plant-Based Alternative Fuels
in the Undergraduate Laboratory

Gabriel Gregorzak1, Mark Baillie1, Jacqueline Fajardo1 & Alenka Hlousek-Radojcic2

1Department of Chemistry & Biochemistry, University of Delaware, 

2Department of Biological Sciences, University of Delaware

A laboratory module intended for an integrated course was developed to highlight relevant and interrelated concepts described in both introductory biology and general chemistry with an enrollment of nearly 500 students. The ever-present depletion of petroleum energy reserves is an ongoing societal concern. Concomitantly, there is growing interest in identifying natural sources of alternative fuels and optimizing the efficiency of their use. To enhance student awareness of alternative fuel availability from natural resources, we have developed a lab centered on the production of biofuels produced from seed-oil extracts. Oil was physically extracted from a variety of seed types including pumpkin, sunflower, walnut, & flax, and utilized an efficient, small-scale, and green approach. The physical extraction technique replaced commonly used organic solvent extraction methods used in many academic and educational labs. Extracted oil was then subject to transesterification to yield the biofuel product. The energy content of this biofuel was measured and compared to ethanol using calorimetric analysis. This distinctive laboratory experience will allow large numbers of freshmen students to recognize the broader implications of their curriculum beyond the boundaries of the classroom.

Brooke Palus

Examining O-xylosyltransferase shedding in Drosophila

Brooke Palus and Erica M. Selva
Department of Biolgical Sciences

O-xylosyltransferase (Oxt) is a transmembrane glycosyltransferase that initiates the first step in heperan and chrondroitin sulfate (HS and CS) proteoglycan biosynthesis. HSPGs and CSPGs are abundant in the extracellular environment of many tissues, such as articular cartilage in humans. In this tissue, HSPGs and CSPGs are essential regulation of signaling pathways that maintain tissue homeostasis. If homeostasis is not preserved, joint tissue will degrade and osteoarthritis (OA) can occur. Elevated levels of circulating Oxt have been detected in human OA patients suggesting shed Oxt may have an extracellular function.  Little is known about Oxt behavior or function once it is released from the plasma membrane. Understanding the role of extracellular Oxt may provide further insight to how cell signaling is disrupted in OA patients.  Cell culture experiments have shown that Oxt, normally located in the Golgi and the endoplasmic reticulum (ER), can be shed by proteolysis activity and move into the media. It is therefore likely that under the appropriate conditions in vivo Oxt will also be shed and become an extracellular protein. The overall aim of this project is to determine if Oxt released from expressing cells in vivo and what, if any, function extracellular Oxt has in organismal development. The data collected thus far shows localization of Oxt to the Golgi and the ER where it could have an active role in HSPG and CSPG biosynthesis. Movement of Oxt from expressing cells to non-expressing cells is observed in the imaginal wing disc of Drosophila larva. Extracellular staining shows that Oxt is found predominantly on the apical surface and can be detected in the peripodial space suggesting it is released from expressing cells.  Western analysis of Drosophila hemolymph indicated Oxt is released into hemolymph, as observed in humans.  The results suggest that cleaved Oxt is found in the hemolymph of Drosophila and future studies will explore the potential function of shed Oxt.

Molly Peters

Analysis of the stability of a Type III Secretion System containing Pathogenicity Island in the human pathogen Vibrio cholerae

Molly C. Peters
, Megan R. Carpenter, and E. Fidelma Boyd
Department of Biological Sciences
            Vibrio cholerae is an enteric pathogen that is the causative agent of the secretory diarrhea, cholera, that affects millions each year. While the O1 serogroup V. cholerae strains are well studied due to their propensity to cause epidemic and pandemic cholera, a second pathovar has been identified that causes inflammatory diarrhea (Shin et al., 2011).  These strains encode a Type III Secretion system (T3SS). This system is present on a Pathogenicity Island (PAI), a mobile genetic element integrated into the chromosome of some non-O1 serogroup strains (Dziejman et al., 2005). The aim of this research was to examine the genetic make-up of T3SS island regions and understand the excision behavior of the region in strain NRT36S (Chen et al., 2007). We constructed a deletion of the cognate island integrase, intV2, and determined the excision phenotype of the island using a two stage nested PCR assay. The results of this assay showed that intV2 is necessary for the excision of the region. Another aim of this work was to examine the evolutionary history of this island region amongst Vibrio and other species of bacteria. A phylogenetic analysis of the conserved T3SS ATPase protein and associated integrases showed unique clustering patterns, supporting the hypothesis that this island is mosaic in structure. Additionally phylogenetic analysis revealed the presence of two different variants of T3SSs within V. cholerae, T3SS𝛼 and T3SS𝛽. Additionally, the grouping pattern on the tree showed a close relationship between the T3SS ATPase of V. cholerae NRT36S, V. parahaemolyticus, and V. mimicus suggesting that this virulence system was passed horizontally among these different species of bacteria in the past (Morita et al., 2013).

Rebecca Pollak

Expression of Neuronal Nitric Oxide Synthase (nNOS) in the Extratesticular Pathway and Its Role in Murine Sperm Maturation

Rebecca Pollak and Patricia A. Martin-DeLeon

Department of Biological Sciences, University of Delaware

Neuronal nitric oxide synthase (nNOS) is one of two constitutive enzyme variants responsible for the production of nitric oxide (NO) from L-arginine in mammalian cells. This membrane-associated protein has been shown to be activated by Ca2+ and to interact with Plasma Membrane Calcium ATPase 1 and 4 (PMCA1 and PMCA4), which negatively regulate it. PMCA4 is the major calcium efflux pump in murine sperm (Wennemuth et al. 2003), where its deletion leads to loss of motility and ultimately male infertility. NO is an important second messenger, and is required for a variety of sperm functions, including motility and fertilizing ability (Ramya et al. 2011). Recently, the DeLeon Lab has shown the expression of PMCA4 in the murine epididymis. However, no work has been done on the expression of nNOS in the extratesticular pathway of any mammalian species. Therefore, we set out to investigate the expression pattern of nNOS in the post-testicular pathway and its role in sperm maturation. Here, we show the presence of nNOS in all three regions (caput, corpus, and cauda) of the murine epididymis in the basal and apical regions of the epithelial lining, via immunofluorescence. Western blotting confirmed the expression of nNOS throughout the epididymis, and showed regional differential expression: there was significantly (P = 0.005) higher amounts in the corpus as compared with the caput and cauda. In the epididymal luminal fluids (ELF), nNOS was found to be significantly (P = 0.027) higher in that from the caudal region as compared with those from the caput and corpus. Similarly, caudal sperm had significantly (P = 0.013) higher expression of nNOS than that in caput sperm. When ELF (combined from all regions) was fractionated via ultracentrifugation, Western analysis showed that nNOS was exclusively present in the epididymosomes (membrane vesicles). Following co-incubation of caudal sperm and ELF, epididymosomal nNOS was transferred to the sperm surface, as detected by flow cytometry. Our finding of sperm acquisition of nNOS from ELF in vitro, as well as elevated levels in caudal sperm, is consistent with the presence of the PMCA4-nNOS interactome in epididymosomes and also a role for nNOS in epididymal sperm maturation.

Thomas Rivas
Recipient of an ASBMB Undergraduate Travel Award to attend the EB2015 meetings

Biochemical Characterization of NOD1, an Innate Immune Receptor

Thomas Rivas, Mackenzie Lauro, Walter Drake, Catherine Grimes, & Brian Bahnson

Department of Chemistry and Biochemistry, University of Delaware

   Innate immunity is an intricate system employed by humans to regulate the trillions of bacteria that live in our body.  One protein integral to the innate immune response is called nucleotide-binding oligomerization domain-containing protein 1 (NOD1).  NOD1 is a cytosolic, membrane-associated protein that is linked to irritable bowel syndrome, asthma, diabetes, and obesity.  These diseases are thought to arise from improper mRNA splicing of NOD1 transcripts leading to a poorly functioning NOD1 protein receptor that can no longer regulate an overstimulated inflammatory response.  Activation occurs when NOD1 binds to a bacterial cell wall component called γ-D-Glu-D-meso diaminopimelic acid (iE-DAP), which then signals the NF-κB cascade to produce pro-inflammatory cytokines and chemokines. This project aims to develop a bacterial expression system to express wildtype NOD1 and the LRR domain, which is the region thought to be involved in ligand binding.  Currently I have produced both constructs in high yield from an E. coli system to allow their biochemical characterization through peptidoglycan pull-down experiments and circular dichroism. 

Hannah receiving her
Honorable Mention Award.

Boston Convention Center Floor where posters were displayed.

Waiting for the Subway at Boston South Station.

Sunset over Boston Commons.
Yes, that is snow in the background.

View of Boston Commons toward the Prudential Building.

Snow still piled high in Boston Commons after a record winter snowfall.

ASBMB Undergraduate Poster Competition.

Gabe, Andre, and Hannah at ASBMB Undergraduate Poster Competition.

Lunch break for Matt and Brooke.

Dinner at Ristorante Limonell after our arrival in Boston.

Lauren and Gabe go Western

Doug Kenny, Hal White, and Lauren Genova at Durgin Park.

A highlight of the meetings was to hear back-to-back plenary talks by Nobelists
Stanley Pusiner and Eric Kandel

Dinner at Ruth's Steak House..

Brooke, Becky, and Lauren
at Quincy Market.

UD Alumni dinner at Durgin Park Restaurant.

UD Alumni: Aparna Sapra, Sarah Martin, Doug Kenny,Sarah's husband,
and Justin Teesdale.

UD Alumni dinner at Durgin Park Restaurant.

Steve Foltz, Mandy Simons, Isaac Hubner, Hal White, and Tom Rivas.

Molly & Isaac Hubner and Evan & Lauren Lebois and spouses at Durgin Park.

Lauren and Evan Lebois, Allen Tseng, and Eric Borer at Durgin Park.

Aparna Sapra, Sara Martin, Doug Kenny, Kyle Martin, and Justin Teesdale at Durgin Park.

Hal White and Mike Cox at Durgin Park.

Eric Borer, ?, Allen Tseng, Courtney Ngai, and Gabe Gregorak at Durging Park.

Brooke, Tom, and Becky
on Washington Srtreet
UD Alumni attending the dinner:
Michael Cox (BA Bioloy 1974),
Marilee Benore (PhD Chemistry 1986),
Daniel Dries (BS Biochemistry 2000),
Amanda Simons (BS Biochemistry 2001),  
Isaac Hubner (BS Biochemistry 2001),
Laura Maliszewski (BS Biology 2001),
Evan Lebois (BS Biochemistry 2007),
Allen Tseng (BS Biology 2007),
Courtney Ngai (BS Biochemistry 2011),
Eric Borer (BS Biochemistry2011),
Steve Foltz (BS Biochemistry 2011),
Ed Miracco (PhD Chemistry 2011),
Justin Teesdale (BS Chemistry 2013),
Sara Martin PhD Chemistry 2014),
Doug Kenny (BS Chemistry 2014),

Aparna Sapra (PhD Chemistry 2014).

Drs. Usher, White, and Laverty discussing dinner plans.

The trip to the Experimental Biology 2015 Meetings in Boston was organized by the University of Delaware HHMI Undergraduate Science Education Program with additional support from travel grants from the American Society for Biochemistry and Molecular Biology. The HHMI Undergradaute Science Education Program, Charles Peter White Fund, Undergraduate Research Program, NIH, NSF, supported research by individual students.

Links to previous EB Meetings:
2001 in Orlando
2002 in New Orleans 2003 in San Diego
2004 in Boston
2005 in San Diego 2006 in San Francisco
2007 in Washington, DC 2008 in San Diego 2009 in New Orleans 2010 in Anaheim 2011 in Washington, DC
2012 in San Diego
2013 in Boston
2014 in San Diego

Return to  University of Delaware HHMI Home Page
Created 13 March 2015,  Last revised 14 April 2015 by Hal White [halwhite at]
Copyright  2015 Harold B. White, Department of Chemistry and Biochemistry, University of Delaware