SAN DIEGO, CA     APRIL 5-9, 2008

See UDaily article

For the past eight 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 conference, the American Society for Biochemistry and Molecular Biology sponsored its 12th Undergraduate Poster Competition in which 13 of the attending 16 UD students participated. Prior to this year, the students from the University had received more awards in this competition than students from any other college or university. This year, in competition with about 140 other students from over 60 institutions, UD students received first prizes in three of the four award categories. In addition, six other UD students received Honorable Mention awards. Another student was a finalist in the Undergraduate Poster Competition sponsored by The American Physiological Society.

2008 Award Winners from The University of Delaware

Three of the four First Prize winners in the 12th Annual ASBMB Undergraduate Poster Competition were students from the University of Delaware. They are Aly Bourreza (left), Patrick Knerr (second from right), and Krista Neal (right). All three were also recipients of ASBMB Undergraduate Travel Awards made to the University of Delaware's Undergraduate ASBMB Affiliate chapter. At the meetings, the University of Delaware Undergraduate Affiliate (UAN) Chapter of the American Society for Biochemistry and Molecular Biology (ASBMB)  received the First Annual UAN Outstanding Chapter Awards for the North East Region and the Nation. Aly Bourreza serves as the chapter's president.

Among the University of Delaware Honorable Mention winners in the ASBMB Undergraduate Poster Competition were Stevie Dreher (left), Stephanie Culver (middle), Carly Dominica (second from right), and Andrew Harmon (right). Vivek Desai and Melissa Warriner were also Honorable Mention winners but are in this photo. Mark Sausen reciving recognition as a finalist in the American Physiological Society's Undergraduate Poster Competition.

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

Prof. Hal White  Chem & Biochem
Prof. Seung Hong, Biol Sci
Prof. Gary Laverty Biol Sci
Prof. David Usher Biol Sci
Tyler Bazzoli
Aly Bourreza
Owen Brady
Stephanie Culver
Vivek Desai
Carolyn Dominica
Stephanie Dreher
Nicole Gentile
Brian Grindel
Andrew Harmon
Patrick Knerr
Gregory Madden
Krista Neal
Mark Sausen
Sergey Sulima
Melissa Warriner

Delaware students with their posters and abstracts.


Tyler C. Bazzoli and Steven D. Brown
Department of Chemistry and Biochemistry
 Identifying Biomarkers of the Mhc Gene
to Investigate Chemosensory Discrimination

Variability in the highly polymorphic genes of the major histocompatibility complex (MHC) plays a fundamental role in influencing the odor of urinary volatiles in the common house mouse (Mus musculus). To better understand the mechanisms underlying MHC-dependent chemosensory signals, it is critical to characterize the chemical nature of MHC-dependent odorants. Urine samples from MHC-genotyped mice were analyzed using capillary gas chromatography. By employing multivariate analysis and pattern recognition techniques on the chromatographic data, it is possible to classify mice by their MHC genotype and to explore which chemical compounds are biomarkers capable of discrimination. Soft Independent Modeling of Class Analogy (SIMCA) of the data was performed and indicated that the observed genotypes were easily distinguishable and well separated, a strong indication that specific compounds differentiated the genotypes. Based on the SIMCA model, a graph of the discriminating power of each compound within the model was generated. The compounds that exhibited a high level of genotype-discriminating power were dimethyldisulfide, methyl methylsulfenylmethyl disulfide, Z-5,5-Dimethyl-2-ethylidenetetrahydrofuran, and E-5,5-Dimethyl-2-ethylidenetetrahydrofuran.The structural similarity between the two disulfide compounds along with the similarity of the two tetrahydrofuran compounds suggest that there may be a biochemical explanation for the role that these four compounds play in differentiating mice with dissimilar MHC genes. The ability to qualitatively determine specific biomarkers associated with genetic differences has an invaluable application in the field of genomic medicine.


Recipient of an ASBMB Undergraduate Travel Award,
First Place Winner in the ASBMB Undergraduate Poster Competition,
President of the outstanding Undergraduate
ASBMB Affiliate Chapter

Evaluating Anti-Androgen Resistance by In-Vitro Selection
Aly Bourreza and John Koh, Department of Chemistry and Biochemistry

Anti-androgens, such as flutamide and bicalutamide (Casodex®), used alone or in conjunction with chemical castration, have been used in the treatment of prostate cancer (PCa) for decades.  However, as many as 30%- 40% of patients treated with anti-androgens acquire a therapy-resistant phenotype after one to three years of treatment.  Furthermore, some patients experience clinical improvement upon cessation of anti-androgens, a condition known as anti-androgen withdrawal syndrome.  Anti-androgen withdrawal syndrome has been associated with mutations to the AR that cause an agonist response to anti-androgens and is one of the most difficult forms of PCa to treat.  The goal of this project is to redesign anti-androgens to evade molecular mechanisms that lead to anti-androgen withdrawal syndrome.  To accomplish this, novel analogs, PLM1 and PLM6, were developed that remain antagonists towards three AR mutants associated with anti-androgen withdrawal syndrome.  In this study, long-term growth analyses of the human LNCaP cell line in the presence of PLM1, PLM6, or bicalutamide have been performed to identify potential AR mutants that would represent an anti-androgen withdrawal phenotype.  After approximately 4- 6 weeks, resistant colonies developed and were selected.  DNA sequence data of the resistant colonies showed various AR mutations.    PLM6 proved to be superior to PLM1 as fewer resistant colonies were observed compared to bicalutamide and PLM1.  This suggests that PLM6 may be effective against this form of resistant PCa.  This work is supported by the Howard Hughes Medical Institute Undergraduate Science Education program and the National Institutes of Health, NIDDK; 3-R01-DK054257-09.

Adam Brady, Muhua Yang, 
Deni S. Galileo

Dept. of Biological Sciences

Modeling Tumor Development: the Role of L1

L1 is a membrane-bound neural cell adhesion protein involved in the development of the nervous system.  However, L1 has been implicated in mediating some of the invasive properties of several cancers including gliomas and breast cancers when proteolyzed to create a soluble ectodomain, which then binds to cell surface integrin receptors in an autocrine/paracrine manner.  L1 has also been shown to rescue cancerous cells from apoptosis.  It was hypothesized that polyclonal antibodies raised against a 15 amino acid peptide corresponding to a critical integrin binding region of human L1 would slow the migration of rat 9L/LacZ and human T98 G glioma cells in vitro, whereas the peptide alone would stimulate migration.  Incubation of cells in the peptide decreased cellular migration, possibly due to competitive inhibition.  The effects of the antibody on cell migration were inconclusive.  Quail QT6 cells have been stably transfected with an L1 ectodomain-Fc fusion protein (L1-Fc) designed to be secreted into the media.  Once purified, it will be applied to 9L/LacZ and T98 G cells and analyzed using automated time-lapse microscopy.  Additionally, glioma cell migration will be analyzed while on top of QT6 cells secreting L1-Fc.  Both conditions are hypothesized to increase the migration rates of these cell lines by mimicking the activity of endogenous L1 ectodomains.  Supported by HHMI and INBRE.


Honorable Mention in the ASBMB Undergraduate Poster Competition

The Effects of Cell Surface NgCAM Expression
on Developing Chick Brain Axons In Vitro

Stephanie Culver
and Deni S. Galileo
Dept. of Biological Sciences

During embryonic brain development, molecular guidance cues work in concert to transduce signals to guide axons to their appropriate targets. Of these cues are proteins of the Ig superfamily, including L1 and its chick homologue, neuron-glia cell adhesion molecule (NgCAM). L1 and NgCAM are neuronal cell surface membrane proteins shown by others to accelerate axonogenesis and increase axon elongation. In vitro bioassays were performed in order to test the hypothesis that NgCAM expression on the cell monolayer will increase rate of outgrowth, axon length, and number of axon processes. Embryonic Day 7 optic tectum (OT) explants were first used to study outgrowth, yet failed to be an efficient and reproducible model. Aggregates were then made from dissociated OT cells and plated onto NIH3T3 monolayers that did or did not express uniform NgCAM and onto monolayers exhibiting patterned NgCAM expression. The aggregates were visualized using static images and time-lapse microscopy by fluorescent membrane dye. Current data has shown an increase in both axon length and number in the presence of NgCAM, suggesting its crucial role as a positive axon guidance cue. Supported in part by an HHMI Undergraduate Science Education Grant and NIH.

Recipient of an ASBMB-NSF Undergraduate Travel Award.
Honorable Mention in the ASBMB Undergraduate Poster Competition

Selected for a symposium presentation

CD44 and Posterior Capsular Opacification (PCO)
Vivek D. Desai, Yan Wang, and Melinda K Duncan
Department of Biological Sciences

PCO arises from epithelial-mesenchymal transition (EMT) of lens epithelial cells remaining behind following cataract surgery. In cancer systems, CD44 mediates changes that eventually result in EMT, although CD44 function in EMT has not been previously studied in the lens. In the normal adult mouse lens, we found CD44 protein and mRNA only in the lens fiber cells. CD44 null mice did not exhibit any qualitative differences in the timing or extent of expression of the EMT marker, -SMA, as compared to WT following cataract surgery suggesting that CD44 is not essential for EMT. But CD44 expression is highly up-regulated in the remaining lens epithelial cells 12 hours following the surgery. This suggests that it is the earliest molecular marker ever described for lens response to injury and may serve as a good model to understand the early events in the lens epithelial response to injury and the sensitization of these cells to later TGFβ mediated EMT. CD44 expression is known to be up-regulated in response to hepatocyte growth factor (HGF) mediated signaling and HGF has been reported to be a potent mitogen for lens epithelial cells. Future work will investigate the hypothesis that HGF mediated signaling up-regulates in the lens in response to injury leading to up-regulation of CD44 expression and sensitization of lens cells to EMT. Funded by the Beckman Foundation, Barry M. Goldwater Scholarship, HHMI, and National Eye Institute.

Honorable Mention in the ASBMB Undergraduate Poster Competition
The Role of N-glycosylation in Drosophila Development: Characterization of alg10
Carolyn Dominica
, Evan Lebois, and Erica Selva
Department of Biological Sciences

Proteins that function extracellularly must undergo the process of secretion and are subject to posttranslational modifications before cell signaling can occur. In this study, Drosophila harboring mutations in alg10 are characterized. alg10 encodes a glycosyltransferase that catalyzes addition of the terminal glucose to the growing dolichol-linked oligosaccharide just prior to its en masse transfer to nascent polypeptides. Our study of P-element excision alleles ofalg10 shows that this gene product is of critical importance during Drosophila development. Removal of both zygotic- and maternal-derived alg10 results in severe and pleiotropic embryonic deficits, demonstrating the importance of regulated N-glycosylation during early Drosophila development. Removal of alg10 from larval eye imaginal discs leads to a disordered eye of reduced size. These effects may be mediated through the Sevenless activated MAP kinase cascade, as we find alg10 mutant eye discs display pathway gain-of-function phenotypes. These findings indicate that regulated N-glycosylation of a component of the Sevenless receptor tyrosine kinase pathway is an important target of Alg10 function. Together, our data suggest that tissue specific addition of terminal glucose to the dolichol-linked oligosaccharide is an essential regulatory event in Drosophila development. Sponsored by HHMI Biological Sciences Education Program. 

Stephanie Dreher1, Daphne Salick2, Lisa Haines-Butterick2, and
 Joel P. Schneider2
1Dept of Biological Sciences and 2Dept of Chemistry & Biochemistry

Honorable Mention in the ASBMB Undergraduate Poster Competition

Bulk Material Properties of ß-Bulge Peptide Hydrogels
for Tissue Engineering

Hydrogels are porous, physically rigid, three dimensional matrices primarily composed of water which show promise as scaffolds to aid in tissue regeneration. The Schneider laboratory has developed a class of β-hairpin peptides that self-assemble into a hydrogel in response to specific stimuli, such as light, pH, temperature, ionic strength, and cell culture media. The peptide MAX8 consists of alternating valine and lysine residues on each β-strand flanking a type II´ β-turn (-VDPPT-) with a glutamic acid at position 15. The kinetics of self-assembly for MAX8 under cellular encapsulation conditions are fast enough to result in homogeneous gel-cell constructs. These constructs can be prepared in a syringe and subsequently shear thin delivered to target sites while maintaining cellular homogeneity. Although it has been demonstrated that MAX8 is a suitable scaffold for tissue engineering applications, this sequence must be prepared by chemical synthesis due to the unnatural amino acid DProline in the turn region. In an attempt to make this material more cost efficient for large-scale application, a new sequence, BBH8, was designed to contain all natural amino acids which can possibly be overexpressed. However, before overexpression, BBH8 was first chemically synthesized and its bulk material properties characterized under physiological and cell culture conditions. Data show that BBH8 behaves analogously to MAX8. Preliminary data also demonstrate that chondrocytes can be encapsulated with homogeneous cellular distribution, while maintaining viability in the network. This suggests that BBH8 is an excellent candidate for tissue engineering. Funding provided by NSF CHEM0348323, NIH R01 DE016386-01, and the Howard Hughes Medical Institute Undergraduate Science Education Program.

Nicole Gentile, Julio Fuentes,
Erica Selva

Department of Biological Sciences

Phenotypic Characterization of the 7H24 Mutant in O-xylosyltransferase

Formation of morphogenetic gradients is a fundamental mechanism of developmental signaling. Establishment of the gradient dictates how tissues respond to extracellular signals to elicit appropriate cellular responses to a secreted ligand. Recently, we have identified a novel mutation in the Drosophila O-xylosyltransferase (oxt) that encodes a key enzyme required for heparan and chondroitin sulfate (HS and CS) biosynthesis, named 7H24.  In Drosophila, HS has been shown to be essential for Wingless (Wg)/Wnt, Hedgehog (Hh) and Decapentaplegic (Dpp)/Bone Morphogenic Protein (BMP) extracellular ligand movement and gradient formation. When HS is absent downstream signaling of these elemental pathways that drive the Drosophila and human developmental program is disrupted. The 7H24 mutation in oxt is a functional null and removal of maternal and zygotic oxt is embryonic lethal with terminal segment polarity cuticle phenotypes suggesting disruption of the Wg and/or Hh signaling pathway. Removal of zygotic oxt causes homozygous mutants to die as pharate adults with small rough eyes and thorax defects that cannot close from the pupal case. We find deficiencies in Wg, Hh and Dpp signaling in the mutant larval wing imaginal discs and evaluation of larval eye phenotypes suggests they do not arise because of defects in cell type specification. 

Brian Grindel1, M. C. Farach-Carson1,2, Joseph Bennett2, Erik Snapp3

1Department of Biological Sciences
2Center for Translational Cancer Research at the Helen F. Graham Cancer Center
3Albert Einstein College of Medicine of Yeshiva University
Regulation and expression of ERp57 in hepatocellular carcinoma

ERp57/PDIA3, a 1,25D3 binding protein with thiol-oxidoreductase activity, resides in the endoplasmic reticulum (ER) owing to a C-terminal QEDL.   ERp57 partitions among cell surface, cytoplasm and nucleus with functions including 1,25D3 binding, ion transport, and redox modulation of transcription. A tissue array immunoscreen of normal and diseased liver sections showed dynamic changes in expression in both cytoplasm and nucleus.  To understand expression of ERp57 in hepatocellular carcinoma (HCC), its steady state distribution was assessed in HepG2 cells using: 1) GFP (green fluorescent protein) tagged ERp57 and, 2) subcellular fractionation.  We also measured the response to various treatments including PMA, 1,25D3, or TNF-α.  High resolution imaging demonstrates localization of ERp57-GFP in the ER along with additional peri-nuclear staining.  A small (<5%) fraction of ERp57 also exists in the cytosol. Co-treatment with PMA, alone and in combination with 1,25D3 for times from 15´ to 1 h did not reorganize EPp57-GFP. In contrast, TNF-α treatment of HepG2 cells moved cytoplasmic ERp57-GFP to the nucleus in 15 min.  Ongoing studies will determine if ERp57 binds to NFkB in HepG2 cells or in normal hepatocytes after TNF-a treatment.  These studies will shed light on redox regulation of transcription by nuclear ERp57 during TNF-a signaling in normal and transformed liver cells.  Supported by HHMI and the CTCR-UD.

Andrew Harmon and Erica Selva

Department of Biological Sciences

Honorable Mention in the ASBMB Undergraduate Poster Competition

Investigating Human and Drosophila Sprinter Function

Within developing tissues, the Wingless (Wg)/Wnt signaling pathway acts as a morphogen, where the extracellular concentration of the Wg ligand governs the level of pathway activation in receiving cells.  Regulated downstream target activation within these receiving cells is essential for proper tissue growth and organization during organismal development.  Our laboratory has identified a novel highly conserved transmembrane protein in Drosophila named Sprinter (Srt), which is required by secretory cells for the release of active Wg ligand (1).  The specific mechanism of Srt function is unknown, however without it, Wg is retained and accumulates in the cells that produce it.  Functional Wg cannot be effectively disseminated to target cells without complex posttranslational processing and packaging (2).  Hence, we hypothesize that Srt functions in the secretion of active Wg ligand by supplying a critical activity required for maturation of Wg protein in its route through the secretory pathway.  The focus of this research is to begin to characterize Srt function and determine if the mechanism of function is conserved between humans and Drosophila. Compartment localization studies in Srt-Wg co-transfected cells show that the majority of Drosophila and human Srt reside in an undefined secretory compartment and high level Srt expression causes cells to produce processes that appear to contain vesicles of Wg protein (Figure 1).  Furthermore, through co-immunoprecipitation we have found that Srt exerts its function by direct physical interaction with the Wg protein and this interaction is conserved across species.  These results suggest that Srt is a multifunctional protein that acts through physical interaction with Wg and perhaps promotes cellular morphological changes that support the dissemination of functional Wg from secretory cells. This data also indicates that these functions are conserved across species. Furthermore, these experiments provide the foundation for evaluating Srt function and conservation in developing Drosophila.

 Recipient of an ASBMB Undergraduate Travel Award
First Place Winner (Proteins) in ASBMB Undergraduate Poster Competition

Selected for a symposium presentation

Metal-triggered hydrogelation of self-assembling β-hairpin peptides
for bioremediation

Patrick J. Knerr, Radhika P. Nagarkar and Joel P. Schneider
Department of Chemistry and Biochemistry

Peptides have been designed which undergo intermolecular self-assembly to form rigid, fibrillar hydrogel networks.  These peptides are unstructured and soluble in aqueous solution, but can be triggered to fold into an amphiphilic β-hairpin conformation under specific environmental conditions.  Once folded, these hairpins self-assemble to form the hydrogel.  Introduction of metal-binding functionality into such a system allows for the development of materials in which hydrogelation can be controlled with particular metal ions.  This work reports a β-hairpin peptide incorporating two strategically-placed cysteine residues, known to bind a host of metal ions including arsenic and zinc.  Equimolar addition of methylarsonous acid to an aqueous peptide solution triggers folding and self-assembly at low peptide concentration (1.0 wt %).  Metal-dependent behavior has been demonstrated using circular dichroism, FTIR, TEM and oscillatory shear rheology.  It is envisioned that this system could be responsive to other cysteine-binding toxic metals, such as mercury and lead.  Since the peptide sequence includes only natural L-amino acids, this peptide can potentially be synthesized biologically and used for large-scale bioremediation of polluted environments.  Funding has been supplied by the Beckman Foundation, the HHMI Undergraduate Biological Sciences Education Program and the NIH.

Gregory Russell Madden1, Andris Kronbergs1, Elizabeth Adams2, Kenneth van Golen1, Randall Duncan1,2

1Department of Biological Sciences and 2Delaware Biotechnology Institute
Parathyroid hormone (PTH) mediated shear-induced actin organization and mechanosensitivity via Ras Homologous A (RhoA) GTPas in osteoblasts

PTH enhances the mechanical loading-indiced increases in bone formation that we postulate results from PTH disruption of the actin cytoskeleton to increase the mechanosensitivity of the osteoblast. Since Ras homologous A (RhoA) GTPase activation promotes action assembly, we examined the effects of these stimuli on RhoA activation, actin organization, and cellular stiffness. Fluid shear (12 dynes/cm2) increases actin stress fiber formation (ASFF) within 15 min in MC3T3-E1 ostepoblasts that is blocked by pretreatment with 50nM PTH. Using a RhoA G-LISA assay, we found that shear activated  RhoA within 15 min of the onset of shear and that 15 min pretreatment with PTH significantly inhibited this activation. AFM quantification of the stress-strain relationship of MC3T3-E1 cells indicated that shear produced a 6-fold increase in cellular stiffness that was blocked by PTH pretreatment. Inhibition of RhoA-dependent kinase (ROCK), an effector protein of RhoA with Y27632 blocked the shear-induced ASFF as well as the increase in cellular stiffness. These changes in cell stiffness closely correlated with shear-induced calcuim signaling. These studies suggest that PTH inhibits shear-induced actin organization through the RhoA-ROCK opathway and that the resultant changes in cell stifness play a role in the PTH-mediated enhancement of osteoblast mechanosensitivity. Supported buy an HHMI Undergraduate Science Education Grant and NIH/NIAMS AR043222.

Recipient of an ASBMB Undergraduate Travel Award,
First Place Winner (Nucleic Acids) in ASBMB Undergraduate Poster Competition

Identification of Residues in SV40 Large Tumor Antigen Important for DNA Replication and Topoisomerase I Binding
Krista Neal and Daniel Simmons
Department of Biological Sciences
Eukaryotic DNA replication is a vital molecular process which is not fully understood. Simian Virus 40 provides an ideal model system. Its genome encodes the protein large T-Antigen (T-Ag), which orchestrates the initiation of replication. T-Ag interacts with host cellular protein Topoisomerase I (Topo I). Topo I binds a T-Ag monomer at two sites, one near the N-terminal domain (residues 83-160) and one at the C-terminal end (residues 602-708). Preliminary data suggest that T-Ag's J-domain and hinge region residues 101-109, may be involved in Topo I binding. We generated single point mutations in full-length T-Antigen and in a N-terminal construct that contains residues 62-262. In vitro replication assays identified three mutants, N99S, L103Q, and C105F to be replication deficient. Furthermore, DNA replication was not stimulated by the addition of Topo I, as is WT T-Ag. ELISAs showed mutant T-Ags N99S, E100A, L103Q, F104V, and E107G have a decrease in Topo I binding as compared to the WT fragment. These data indicate that this region is important for Topo I binding and residues N99 and L103 may be necessary for DNA replication. Other assays will be performed to verify that the mutants' deficiency in DNA replication is due to a defect in Topo I binding and not to other causes. This work is funded by a PHS Grant from the National Cancer Institute to DS and a HHMI Undergraduate Award to KN.


Finalist in the American Physiological Society's Undergrauate Poster Competition

The Exercise Pressor Reflex in Hypertensive Humans
Sausen, Mark T., 1Delaney, E.P., 1,2Stillabower, M.E., 1,2Farquhar, W.B. 1
University of Delaware, 2Christiana Care Health System Newark, DE

During dynamic handgrip exercise (DHE), there is an increase in blood pressure (BP) mediated by “central command” (a neural drive originating in the brain) and the “exercise pressor reflex (EPR)” (a neural drive originating in skeletal muscle). The EPR has been shown to be overactive in hypertensive rats.
Purpose: To examine the EPR in hypertensive (HTN) humans during DHE and post-exercise ischemia (PEI). Hypothesis: The exercise- and ischemia-induced increase in BP will be greater in HTN compared to normotensive (NTN) adults. Methods: 12 HTN (64±1 yrs) and 15 NTN (65±1 yrs) adults were recruited. Beat-to-beat mean arterial pressure (MAP), systolic BP (SBP), and diastolic BP (DBP) were measured non-invasively at the finger (Finometer). DHE at 60% of maximal voluntary contraction was performed for 3 minutes followed by 2 minutes of PEI (upper-arm occlusion cuff inflated to 200 mmHg to trap metabolites and isolate the EPR). A repeated-measures ANOVA was used to examine differences between conditions and groups. Results (mean±SEM): DHE resulted in increased MAP that was not different between groups (HTN: Δ = 16±3 vs. NTN: Δ = 12±3 mmHg). During PEI the change in MAP, SBP, and DBP from baseline was greater in HTN than NTN (MAP: Δ = 12±3 vs. Δ = 6±1 mmHg, SBP: Δ = 17±4 vs. Δ = 9±2 mmHg, DBP: Δ = 7±2 vs. Δ = 3±1 mmHg; p<0.05). Conclusion: These findings suggest HTN humans have an overactive EPR. Supported by NIH grant RO3 AG-23836.

Sergey Sulima
1, Konstantin Musiychuk1,
Fabienne B. Bouche2, Claude P. Muller2, Vidadi Yusibov1, and Vadim Mett1.

1Fraunhofer USA Center for Molecular Biotechnology, Newark, DE 19711, USA

2Laboratoire National de Santé, Institute of Immunology, 20A rue Auguste Lumière L-1950 Luxembourg

Vice president of the outstanding Undergraduate ASBMB Affiliate Chapter

Expression and characterization of Loop- and Helix-forming epitopes of Measles Virus Hemagglutinin in plants

The number of cases of acute Measles Virus (MV) in the United States plummeted 98% since 1963, when a live attenuated vaccine has been introduced. However, such a vaccine requires constant refrigeration to preserve potency. More importantly, the presence of maternal antibodies interferes with effectiveness of the vaccine before ~9 months of age. These reasons present a major impediment for the vaccination of young children, especially in developing countries. Here, we report the transient expression of two MV hemagglutinin epitopes in Nicotiana benthamiana. These loop- (L) and helix- (H) forming epitopes are not recognized by maternal antibodies, have been shown to generate a protective immune response in mice, and could be used to develop a vaccine for infants before the age of 9 months. The epitopes were fused to the surface loop of the thermostable enzyme of Clostridium thermocellum, and produced in plants through a combination of viral and bacterial vectors. Purified antigens were characterized by SDS-PAGE followed by immunoblotting. Immunological testing showed that the L- and H-epitopes are recognized by L- and H-specific antibodies, respectively, thus successfully mimicking natural antigenic properties.

Melissa Warriner,
Timothy Schwartz, Julia Engstrom, and Eric Kmiec

Department of Biological Sciences

Recipient of an ASBMB Undergraduate Competitive Travel Award.

Honorable Mention in the ASBMB Undergraduate Poster Competition

Gene Repair in sub-S phase Cell Populations and Cell Cycle: Response to Quadruplex Oligonucleotides

Targeted nucleotide exchange (TNE) relies on the use of a short  synthetic oligonucleotide (ODN) designed to be complementary to  a  target  sequence  in  the  genome  except  for  a  centrally  located  mismatch, which directs the desired base change in the DNA.  The  repair  reaction  is  believed  to  be  enhanced  by  mechanisms  that  promote a more open conformation of the DNA, thus, enabling the  target site to be more accessible for the binding of the  oligonucleotide.  One such method is through the modulation of cell cycle progression to increase the population of cells in S phase, wherein targeting of a single base pair is enhanced.  Studies aimed at demonstrating the variations in correction in relation to cell cycle measured repair frequency late in the reaction cycle.   Our work aims to discern variations in repair levels in sub-phases of S as cells enter and progress through this phase, in the presence of the oligonucleotide.    In addition, we evaluate gene expression  patterns of  several cell  cycle genes that may help denote  the  changes in  cell cycle distribution  as  a function of gene  repair  events.   Additional research has been performed analyzing gene expression patterns in malignant versus non-malignant esophageal cancer cells in response to treatment with G-rich oligonucleotides  (GRO).   It has been shown that these single-stranded DNA molecules which are comprised primarily of guanosine residues induce retardation in the progression of the cell cycle, and result in a  sub-G1 population of  apoptotic cells.   Successful inhibition of growth of malignant, but not nonmalignant, cells has been seen.   Thus, G-rich ODNs may be guiding the selective killing of tumor cells.  I am currently analyzing the RNA levels of apoptosis genes incubated with GROs to understand how the cells are responding, and which pathway may be responsible for the induction of apoptosis.  Funded by Howard Hughes Medical Institute.

The trip to the Experimental Biology Meetings in San Diego 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 Beckman Scholars Program,  and the Women Scholars Program. The HHMI Program, the Beckman Scholars Program, Charles Peter White Fellowships,  and the Undergraduate Research Program supported research by the students.

Aly Bourreza explains her poster to Dr. Ann Aguanno, Corrdinator for the Northeast Region of ASBMB-UAN

Aly Bourezza Discusses her poster with Dr. Marilee Benore-Parsons (UD PhD Chem 1986)

Nicole Gentile talking to Sergey Sulima and Pat Knerr.

Dr. Usher and Brian Grindel at Brian's poster.

UD Students at the Old Town Mexican Cafe enjoying dinner.

Nicole Gentile explaining her poster.

Adam and Aly think Sergey has something interesting in his glass.

Pat Knerr received his First Prize Award from Dr. Kathleen Cornely.

Judge Dr. Paul Craig questions Stevie Dreher about her research.

That was quite a meal at Osteria Panevino Italian restaurant in the Gaslamp District.

Pizza for lunch.

UD Undergraduate memnbers of the ASBMB UAN Chapter with Dr. White, adviser, receiving the National Outstanding Chapter Award.

UD Alumni and faculty at Old Town Mexican Cafe.

UD students and alumni at Old Town Mexican cafe.

Just a small section of the huge number of posters set up each day in the San Diego Convention Center.

Publisher's Row and other vendor exhibits in the San Diego Convention Center.

A break from the Scientific session for a bit of California sun.

Part of Los Angeles from the air. If you look closely you can see where Dr. Usher used to live.

Melissa Warriner answering a judge's question at the ASBMB Undergraduate Poster Competition.

Yes, it is still winter in the Colorado Rocky Mountians.

Sergey, Aly, Krista, and Pat at the San Diego marina

Sergey, Krista, and Pat taking a break from the sessions.

Vivek, Sergey, Adam, Dr. White and Pat at the ASBMB Mixer.

It was at the Las Vegas Airport that  Tyler and Adam deplaned to seek new  fortunes.

Santa Catalina Island from the air as we headed home.

Valley of Fire, Nevada, from the air on our return trip.

Lake Mead in Nevada was surrounded by 100s of miles of dry land.

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Created 8 November 2007,  last revised 9 July  2008 by Hal White [halwhite at udel.edu]
Copyright 2008, Harold B. White, Department of Chemistry and Biochemistry, University of Delaware