Sixteen University of Delaware Undergraduate Researchers participated in the  EXPERIMENTAL BIOLOGY MEETINGS
in San Francisco, April 1 - 5, 2006

University of Delaware undergraduate researchers live up to their national reputation.

Front Row left to right:  Eric Hardter, Agata Bielska, Jessica hall, Kristen Reese, Liang-I Kang, and James Kuczmarski
Back Row left to right: Kellie Machlus, Alfred Smith, Andrew Farach, James Kelleher, Madeline Gregorits, Vivek Patel, and Patricia Hansen. (Brett Hensley not shown) Recipients of Honorable Mentions in the ASBMB Undergraduate Poster Competition are holding certificates.  This year UD students received more awards in this competition than students from any other school in the country.

Prof. Hal White  Chem & Biochem
Prof. David Usher Biol Sci
Prof. Gary Laverty, Biol. Sci.
Dr. Seung Hong, Biol Sci
Nicole Barkley*, Biol Sci
Agata Bielska, Chem & Biochem
Karla Boyd*, Biological Sciences
Andrew Farach, Biology
Madeline Gregorits, Biological Sci.
Jessica Hall, Animal Science
Patricia Hansen, Biology
Eric Hardter, Biochemistry
Brett Hensley, Medical Technology
Liang-I Kang
, Biol Sci

James Kelleher
, Biochemistry

Jamie Kuczmarski, Physical Therapy
Kellie Machlus, Biochemistry
Vivek Patel, Biol. Sci.
Kristen Reese, Biol. Sci
Alfred Smith, Biochemistry

UDaily article about Practice Session
at McKinly Lab March 7.
UDaily article about the trip.
Photo Gallery of Trip
             *Unable to attend due to conflicting presentations at Cancer Society meetings.

University of Delaware Student Poster Presentations and Abstracts.

Akt is Preferentially Expressed in PC-3 Cells Adhering to Bone Matrix

 Nicole Barkley, Freddie Pruitt, *Kathleen Ignatoski, Bianca Graves, Meghna Naik, Ulhas P. Naik Carlton R. Cooper

University of Delaware, Biological Sciences,
*University of Michigan; Department of Urology; Ann Arbor, MI

Prostate cancer (PC) commonly metastasizes to the skeleton, where it becomes highly resistant to chemo-therapeutics. The components of the bone extracellular matrix microenvironment and other secreted factors have been implicated in PC cell proliferation. The purpose of this project was to determine the effects of PC-3 cells adhering to bone substrates on Akt activation. PC-3 cells were plated on substrates composed of secreted factors from osteoblastic-like cells (SaOS2), bone stromal-like cells (HS-5), as well as collagen type-1, a major component of the bone matrix, and fibronectin. Western analysis was performed to resolve the phosphorylated Akt. We hypothesize that prostate cancer cells grown on the substrate of secreted factors from osteoblastic (SaOS2) and bone stromal (HS-5) cells will preferentially stimulate the activation of Akt. Also we hypothesize that PC-3 cells grown on type-1 collagen will preferentially stimulate Akt activation rather than grown on fibronectin. Western blot analysis of Akt activation showed the greatest increase in PC-3 cells on SaOS-2 secreted substrate compared to the control (plastic) and HS-5 conditioned media. In addition, we present data showing that Akt is activated preferentially on collagen-type 1 compared to fibronectin. Lastly, we demonstrate that ErbB2 is preferentially expressed on PC-3 cells grown on soluble bone-marrow extracts compared to kidney extracts. These data suggest that secreted factors, including collagen type I, predominately from osteoblastic cells, enhance prostate cancer cell survival in the bone microenvironment and these factors may contribute to drug resistance.

  ASBMB Honorable Mention
Hyperphosphorylation of tau induces local structural changes

Agata Bielska and Neal J. Zondlo
Department of Chemistry and Biochemistry

Protein phosphorylation is a ubiquitous regulatory and signaling mechanism used throughout the cell.  We have analyzed the conformational effects of serine-threonine phosphorylation in proline-rich peptides whose sequences were derived from the protein tau.  Tau is a member of the microtubule-associated-proteins (MAPs) and binds microtubules in neurons to stabilize their elongated structure in the axon.  In Alzheimer’s disease and other tauopathies, tau becomes hyperphosphorylated.  This is thought to cause a conformational change resulting in the dissociation of tau from microtubules and aggregation into neurofibrillary tangles (NFTs).  We have observed significant conformational changes upon tau phosphorylation by circular dichroism spectroscopy (CD), fluorescence resonance energy transfer (FRET), and NMR.  A common phosphorylation-induced structural change in the proline-rich peptides favored a type two polyproline helix (PPII) secondary structure.  Funding for this work was provided by HHMI and University of Delaware Research Foundation.


Factors Secreted by Bone Stromal Cells and Osteoblasts Regulate Prostate Cancer Adhesion to Bone Endothelium

Karla BoydFayth Miles, Michael Dumas, Linda Sequenia, Bianca Graves, Robert Sikes, Mary C. Farach-Carson, and Carlton Cooper

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

Prostate cancer (PC) is a leading cause of cancer death in men in the United States, and bone metastasis is a common, painful, and fatal complication. (Szostak and Kyprianou, 2000). It has been shown that PC cells first adhere to bone marrow endothelium before moving to bone matrix (Lehr and Pien! ta, 1998). The PC adhesion must be regulated so that cells do adhere, but not too strongly, in order to achieve the traction they need to reach the matrix. It is yet unclear how this happens, but evidence suggests that it is due to factors in the bone microenvironment, including growth factors, integrins, and cytokines. Here we examined the effects factors secreted by bone stromal cells (HS-5) and osteoblast-like cells (SaOS) have on PC cell lines’ (LNCaP and C4-2B4) adhesion to bone marrow endothelial cells (BMEC). LNCaP cells do not metastasize but C4-2B4 cells do in a mouse model. Initial findings indicate that C4-2B4 cells exposed to HS-5 and SaOS conditioned media are less adherent to BMEC compared to control, while LNCaP cells exposed to HS-5 and SaOS conditioned media were more adherent to BMEC compared to control. These preliminary observations suggest that factors secreted by HS-5s and SaOSs inhibit strong adhesion of the more metastatic C4-2B4 cells and encourage adhesi! on of the less metastatic LNCaPs to bone marrow endothelium, allowing only C4-2B4s to move on to the bone matrix. KB supported in part by HHMI Undergraduate Science Education Program.

Exploring O-GlcNAcylation and phosphorylation in the developing chick brain

Andrew M. Farach and Deni S. Galileo.

Biological Sciences, University of Delaware, 248 Wolf Hall, Newark, Delaware, 19716

Interest in modification of proteins by O-linked beta-N-acetylglucosamine (O-GlcNAc) is growing rapidly due to its continued implication in the regulation of cellular processes. Since roles for O-GlcNAc in brain development have not yet been described, we characterized the expression of O-GlcNAc in the developing chick midbrain (optic tectum) to see if patterns existed in specific cell types, in subcellular processes like axons, or in specific proteins. Based on the recurrent O-GlcNAcylation of highly phosphorylated proteins in other vertebrate systems, neurofilament modification in neuronal axons was examined. Our studies indicate that a regulated developmental pattern of O-GlcNAcylation exists in the developing chick brain. Immunohistochemical analyses in sections of progressive stages of development suggest upregulation of O-GlcNAc in the ependyma, tectobulbar neuron bodies, and radial glial processes, but not in neurofilament (+) axons. In contrast, O-GlcNAcylation of most axons occurred in cultures made from embryonic day 7 brain cells. Western blot analysis showed O-GlcNAc modification of a few discrete proteins throughout development, including one of approximate weight of vimentin (52kDa), an intermediate filament marker of radial glia in the chick brain.  These results and labeling of radial glia in brain sections indicate that it is vimentin that is modified by O-GlcNAcylation. This potentially indicates an undescribed developmental role for O-GlcNAc modification that could include vimentin intermediate filaments as well as neurofilaments.  Funded by HHMI, Charles Peter White Fellowship, and UD Undergraduate Research Program.

Spontaneous Colonization of Osteoblastic Prostate Cancer Cells In Vivo:
A New Model of Metastasis to Bone

Madeline Gregorits, Ronald R. Gomes, Jr.
and Robert Sikes

Department of Biological Sciences

There are few models available to study spontaneous osteoblastic prostate cancer metastasis to bone. Current models require orthotopic injection and more than six months to form metastases in bone, while intracardiac injection, specifically with PC-3 cells, results only in osteoclastic bone metastases. We have hypothesized that differences in bone turnover between mice and humans is the main limitation for the spontaneous and rapid colonization of marrow forming bone by osteoblastic prostate cancer cells, as bone turnover rates in adult mice do not mimic the higher, continuous turnover rates observed in humans.  SCID/bg mice were subjected to two and three week periods of tail suspension to enhance bone turnover, followed by intracardiac injection of C4-2 prostate cancer cells and a return to normal weight bearing activity. MicroCT analysis revealed a significant reduction in trabecular bone volume and an increased porosity in the femurs of tail-suspended mice relative to controls. After three weeks of tail suspension and six weeks post C4-2 cell injection, 100% of the mice demonstrated detectable serum PSA levels. Immunohistochemical staining of femurs for PSA revealed the localization of PSA positive, C4-2 cells in marrow and trabecular spaces. These results suggest that this novel model combining tail suspension in an immune compromised mouse strain and intracardiac injection could allow for the direct testing of therapeutic agents that interfere with the process of osteoblastic prostate cancer colonization of bone. Funding provided by the Howard Hughes Medical Institute and University of Delaware Research Foundation.

Analysis of hepatic gene expression in chickens with hormonally-induced lean and fat phenotypes

Jessica Ann Hall1, Robert J. Templeman2,
and Larry A. Cogburn1:

Department of Animal and Food Science,
University of Delaware, Newark, DE 19717,
2Department of Animal Science, Michigan State University, East Lansing, MI 48824-1225

The purpose of this project was to use microarray analysis to unravel the genetic circuits controlling deposition and metabolism of fat in a hormonally-induced obesity model.  The abdominal fat content and free fatty acid levels of four-week-old chickens were dramatically altered after chronic infusion (two weeks) of exogenous corticosterone (CS) or thyroid hormone (T3), producing a fat and lean phenotype, respectively. Our Del-Mar 14K Chicken Integrated Systems Microarray (Geo Platform GPL1731) was used to identify differentially expressed hepatic genes (i.e., 1.4-fold difference).  In the contrast of fat (CS) and lean (T3) phenotypes, 136 genes were up-regulated by CS, whereas 64 genes were up-regulated by T3.  An additional study was designed to examine gene response to acute hormone infusion (six days) of CS or T3, alone or in combination.  Both studies revealed several transcription factors (Spot14, CEBP2, etc.), metabolic enzymes (malic enzyme, fatty acid synthase, etc.) and transport proteins (LFABP, adipophilin, etc.) that control lipogenic (CS induced) and lipolytic (T3 induced) pathways.  This project provides new insight into genetic control of metabolic disorders, such as diabetes and obesity.  This work was supported by a USDA Training Grant (2004-38411-14734) and by a USDA-IFAFS Animal Genome Program (00-52100-9614). 

ASBMB Honorable Mention

Breast cancer metastasis to brain in a new in vivo chick embryo model system

Patricia Hansen and Deni Galileo

Biological Sciences, University of Delaware, 248 Wolf Hall, Newark, Delaware, 19716

Breast cancer metastases to brain are often rapidly lethal. This project has established the chick embryo as a new model for studying extravasation of breast cancer to brain. Human MDA-MB-231 and MDA-MB-435 breast cancer cell lines were infected with retroviral vectors expressing the lacZ marker gene and/or the green fluorescent protein (GFP) gene for identification of cells in vivo and in vitro. Approximately 50,000 cells were injected into the extraembryonic vasculature of 5 day embryos, followed by dissection of the brain, fixation and beta-galactosidase staining, and preparation of routine H&E paraffin sections less than 2 weeks later.  Cryosections were also prepared and subsequently immunostained for marker genes. Numerous lacZ(+) tumor cells were present on the outside of the brain after 10 days in the embryo, and cells were clearly located in brain tissue outside blood vessels, demonstrating their extravasation. GFP expressing tumor cells were recovered from dissociated brains and subjected to quantitation by flow cytometry and clonal formation analyses after puromycin drug selection. They were detectable by flow cytometry, but drug selection and clonal analysis was a more sensitive and accurate method of quantitation of tumor cell extravasation into brain.  These experiments have validated the use of this new model for the study of breast cancer metastasis to brain, and now will allow molecular mechanisms of metastasis to be investigated. Furthermore, lacZ and GFP both were useful markers for localization and quantitation of tumor cells. Supported by the Howard Hughes Medical Institute, the Charles Peter White Fund, and the University of Delaware Undergraduate Research Program.

Spectroscopic Elucidation of Selected beta-Hairpin Turn Sequences

 Eric Hardter and Joel Schneider

MAX 1 is a 20 amino acid beta-hairpin comprised of valine-lysine repeats and a type II' turn sequence of -ValD-ProProThr-. This peptide undergoes triggered folding from random coil to beta-hairpin conformation. Subsequent self-assembly of the hairpins affords hydrogel material which is currently being investigated for use in tissue engineering. Circular dichroism is used extensively to assess the secondary structure of these peptides during folding and self-assembly. However, it is not known definitively how the turn sequence contributes to the spectroscopic data obtained. To elucidate this matter, a series of 6-residue turns (C-V-X-X-T-C) have been synthesized, and subjected to circular dichroism, nuclear magnetic resonance, and infrared spectroscopic methods. The contribution of the turn region to the overall spectroscopic signal of the hairpin will be discussed. Furthermore, all experiments were performed under both oxidizing and reducing conditions, so as to further determine the impact of a disulfide bond on these turns. This research was supported by the HHMI Undergraduate Science Education Program.

ASBMB Honorable Mention

Effects of the monomeric disintegrin eristostatin on melanoma intracellular protein tyrosine phosphorylation

Brett Hensley, Carrie Paquette-Straub,
and Mary Ann McLane

Department of Medical Technology,
University of Delaware,
Newark, DE 19716-3720

Disintegrins, low molecular weight proteins isolated from snake venom, can interact with many cell types and adhesion molecules. One disintegrin, eristostatin (Er), has the ability to inhibit platelet aggregation and human and murine melanoma cell metastasis. Recent studies using wound healing assays suggest that Er may inhibit melanoma cell motility. No mechanism elucidating Er’s mode of inhibition has been discovered thus far. Using immunoprecipitaton with antiphosphotyrosine antibody, we evaluated the effect of Er (3000nM) on tyrosine phosphorylation of intracellular proteins within five human melanoma cell lines: C8161, M24met, 1205 LU, MV3, and WM164. We determined that Er notably changed the protein phosphorylation within all five cell lines. The 1205 LU cell line showed an increase in protein phosphorylation from 100-140 kDa, 60-75 kDa, and 37-45 kDa when treated with Er compared to cells treated with water. M24met cells showed a similar increase in protein phosphorylation at 95-100 kDa and 40-45 kDa when treated with Er. A decrease in protein phosphorylation was found at 40-45 kDa for Er-treated C8161 cells and at 95-100 kDa and 135-140 kDa for Er-treated MV3 cells. Er-treated WM164 cells showed a decrease in protein phosphorylation at 55-60 kDa and 135-140 kDa as well as an increase at 125-130 kDa. A review of all known tyrosine phosphorylated proteins involved with cellular motility provided many possible candidates including Pten, EGFR, Fak, FGFR, PDGFR, Pyk2, Hck, and others. Using another approach, without immunoprecipitation, in order to examine the same intracellular phosphorylation yielded contrasting results, which will be examined and summarized.  Further experimentation evaluating this alternative method is needed in order to validate results.  Research supported by NIH (CAO98056, MAM) and Charles Peter White Scholarship (BH).

The Role of Junctional Adhesion Molecule A (JAM-A) in the Corneal Epithelium

Liang-I Kang,
Yan Wang,
Vesselina Cooke,
 Ulhas P. Naik, and Melinda K. Duncan

Department of Biological Sciences

Junctional Adhesion Molecule-A (JAM-A) is a 32 kDa protein that has been implicated in a variety of roles in the body, including platelet activation and adhesion, leukocyte migration, angiogenesis, and the structural integrity of endothelial and epithelial cell layers.  Recently, our laboratory has begun to characterize JAM-A function in the eye since its expression was upregulated in the lens of Pax6 transgenic mice.  The presence of JAM-A, JAM-B, and JAM-C mRNA in the adult wildtype lens and cornea was confirmed through Real Time RT-PCR, with no significant level of compensatory expression of JAM-B and JAM-C in JAM-A -/- tissue.  Using immunohistochemistry, JAM-A protein was found in the blood vessels of the developing eye as early as 12.5 dpc (days post coitum) and in the corneal epithelium by 13.5 dpc.  PLAP (placental alkaline phosphatase) and beta-galactosidase reporter gene activity was detected in the JAM-A heterozygous and homozygous cornea, indicating the insertion of the gene-trap construct in these mice, and immunohistochemistry showing the absence of JAM-A staining in knockout cornea validated both JAM-A antibody specificity and the knockout genotype.  We hypothesize that JAM-A has a role in the maintenance of the cornea and future functionality studies will include corneal wound healing and corneal permeability assays. This project has been funded by NIH and the Arnold and Mabel Beckman Foundation.

ASBMB Honorable Mention

Regulation by Cholesterol of the Gene Expression of Spot 14 in Adipocytes

James Kelleher, John David, and David Usher

Department of Biological Sciences,
University of Delaware

Thyroid hormone responsive Spot 14 (THRSP) is a transcription co-factor that is expressed in the liver and adipocytes.  Spot 14’s expression in the liver is controlled by various factors which suggest that it acts as a control point in the lipogenesis pathway. However, its synthesis has also been shown to be under the control of the liver X receptor (LXR), a transcription factor that is sensitive to cholesterol levels.  Spot 14’s regulation in adipocytes has yet to be investigated.  In this study we used cholesterol depletion (β-cyclodextrin treatment) and peroxisome proliferator-activated receptor (PPARγ) and LXR agonists, rosiglitizone and T0901317, respectively, to examine Spot 14’s regulation in 3T3-L1 adipocytes.  Gene expression of these treated cells was examined through quantitative PCR for Spot 14 and its hypothesized target genes, fatty acid synthase (FAS), ATP-citrate lyase (ACLY), malic enzyme (ME), and phosphoenolpyruvate carboxykinase (PCK1).  Spot 14’s expression in 3T3-L1 cells decreased with the cyclodextrin treatment and increased with the T0901317 treatment, indicating direct control by LXR.  T0901317 also induced upregulation in Spot 14 target genes FAS, ME, and ACLY, but the cyclodextrin treatment had little to no effect on these genes. Rosiglitizone treatment also had very little effect on Spot 14 or its target genes.  These results indicate that adipocyte cholesterol levels are important for controlling Spot 14 synthesis. This research was funded in part by the Howard Hughes Medical Institute Undergraduate Science Education program.

Lack of association between body mass index and acute hypertonic saline induced increases in blood pressure

J.M. Kuczmarski, E.P. Delaney, M.M. Wenner, A.V. Prettyman, M.E. Stillabower, and W.B. Farquhar

Department of Health, Nutrition, and Exercise Sciences
University of Delaware, Newark, DE 

Salt sensitivity of blood pressure (BP) is thought to be greater in obese subjects compared to normal weight individuals.  The mechanisms underlying sodium-induced increases in BP have not been fully elucidated.  We hypothesized that body mass index (BMI) would be associated with sodium-induced increases in BP.   We retrospectively examined data from 44 healthy subjects (mean ± sem: 251 yrs) that completed a standardized 60-minute intravenous infusion (0.15 ml/kg/min) of 3% sodium chloride (hypertonic saline infusion: HSI).  The HSI protocol is a robust sodium and volume stimulus, and allows acute BP responses to be quantified.  Blood pressure was assessed on a beat-to-beat basis non-invasively with a Finometer.   In this cohort, BMI ranged from 19-35 kg/m2 (25±1 kg/m2).  Serum sodium increased pre- to post-infusion (135±0.6 vs. 141±0.4 mmol/L; p < 0.01) and hematocrit declined (39±0.7 vs. 36±0.6 %; p < 0.01) during the 60-minute HSI.  Baseline mean BP was 80±2 and this increased to 90±2 mmHg (p < 0.01) at the end of the infusion.  BMI did not correlate with the increase in systolic BP (r=0.04, r2=0.002, p=0.78), diastolic BP (r=0.11, r2=0.013, p=0.47), or mean BP (r=0.03, r2=0.001, p=0.87).  Also, no significant correlation was found between skinfold-derived percent body fat and increases in mean, diastolic, or systolic BP.   In conclusion, within a range of 19-35 kg/m2, there was no association between BMI and the hypertonic saline-induced increase in BP.  Supported by NIH grant R15 HL74851 and The University of Delaware Undergraduate Research Office

Expression and characterization of short analogs of the Adenosine 2A Receptor

 Kellie Machlus and Clifford Robinson

Department of Chemistry and Biochemistry
and the Delaware Biotechnology Institute

Although much is known about the structure and corresponding function of soluble proteins, the folding mechanisms and pathways of G protein-coupled receptors (GPCRs) are poorly understood.  Our goal is to understand the specific transmembrane interactions that stabilize integral membrane proteins, and to develop a model for GPCR folding. In this investigation, the Adenosine 2A Receptor (A2AR) was studied as a model GPCR.  Like all GPCRs, A2AR contains seven membrane-spanning alpha-helical domains. Recombinant DNA methods were used to create a mini-gene of the A2A receptor that contains trans-membrane helices two and three, and another containing five and six.  Using the pET31b(+) system, fusion constructs of these peptides have been sufficiently over-expressed in E. coli, and purified by Ni-Chelate chromatography.  Currently, studies are underway to characterize the structure of the two-helix fragments, and measure its interactions with other trans-membrane helices from A2AR. Ultimately, we are using these and similar constructs to learn about the assembly pathway and structure of A2AR.  This project was funded by HHMI and the NIH.

High resolution time-lapse analysis of glioma tumor cell migration

Vivek P. Patel, Joseph S. Fotos, Deni S. Galileo.

Biological Sciences, University of Delaware, 248 Wolf Hall, Newark, Delaware, 19716

Methods generally in use to measure tumor cell movements lack sufficiency in numbers of cells analyzed, precision of measurements, or temporal and spatial resolution.  Here, the study of glioma cell motility was greatly enhanced using a fully automated time-lapse microscopy system capable of collecting and analyzing motility data at closely spaced time points (5 min), over long periods (24 hrs), and under several different experimental conditions in parallel. This system was designed to be significantly more versatile and less costly than commercial systems and collected data under phase contrast and widefield fluorescent illumination concurrently.  Human and rat glioma cell lines were plated under a variety of conditions and subjected to time-lapse microscopy, cell tracking, and quantitative analysis of velocity, total accumulated distance, and directionality for individual cells or for averaged cell populations. Quantitation of glioma —scratch“ assays revealed changes in motility parameters after 1) anti-adhesion molecule antibody-treatment, 2) adhesion molecule-transfection, or 3) antisense-adhesion molecule viral vector infection. Fluorescently labeled glioma cells were tracked while migrating on top of cell monolayers that expressed ectopic adhesion molecules, and this resulted in significantly reduced glioma migration velocities.  Our methods of analysis revealed changes in glioma cell motility after experimental treatments that would not be discernable by other common methods. Supported by the HHMI Undergraduate Research Program, the McNair Scholars Program, and the U.D. Undergraduate Research Program.

Hyal3: Redefined as a Reproductive Hyaluronidase

Kristen L. Reese and Patricia A. Martin-DeLeon,

Department of Biological Sciences

ASBMB Honorable Mention

Fertilization in mammals requires the successful completion of cumulus cell dispersion, zona pellucida binding, and perivitelline space penetration.  The digestion of hyaluronan, which is abundant in the cumulus cell matrix and zona pellucida, is essential for permeating the vestment of the oocyte and is performed in the mouse by a family of enzymes termed the reproductive hyaluronidases.  HYAL3/Hyal3, located on human chromosome 3p21/mouse 9F1 and previously thought to be a somatic hyaluronidase, shares great similarity to identified reproductive hyaluronidases, yet there have been no studies to document a role in fertilization.  Recently it has been shown that sperm lacking functional Spam1 are able to penetrate an oocyte, indicating related hyaluronidases can functionally contribute to fertilization.  Interestingly, humans lack a functional reproductive hyaluronidase other than SPAM1 on the 7q31 chromosome.  Hyal3 has the highest amino acid identity (80%) to its human homolog and shares high testicular expression and identity to SPAM1.  Therefore, it is particularly important to investigate the potential role in the fertilization process of humans in addition to or in the absence of a functional SPAM1 protein.  Here, we demonstrate that in addition to its testicular expression, Hyal3 is also present on the head of sexually mature sperm and is involved in acrosomal exocytosis, an important step in fertilization.  Hyal3 is also present in extra-testicular tissues such as the epididymis and uterine luminal fluid of females in estrus.  Based on the tissue expression patterns of Hyal3, its functional domain similarities, and involvement in acrosomal exocytosis, a redefinition of this protein is in order.  Further investigation will be required for reclassification to extend to the human model.  This research is funded by the Howard Hughes Medical Institute and NIH grant #R01 HD38273.

Synthesis and Applications
of Arginine Mimetics

Albert Smith and Neal Zondlo
Department of Chemistry and Biochemistry

Protein-protein, protein-RNA, and protein-DNA interactions are broadly mediated through the guanidinium functionality of arginine residues.  However, specific recognition by arginine is limited, because the guanidinium functionality is attached to a linear alkyl group.  To achieve specific molecular recognition, arginine mimetics are used, which place functional groups adjacent to a guanidinium.  In order to specifically target arginine-mediated recognition, we developed convenient syntheses of alpha- guanidino acids, in which the amine of an amino acid is converted into a guanidinium.  The alpha-substituted guanidiniums of guanidino acids and the side chain of the amino acid work synergistically toward molecular recognition with greater affinity for the target site.  We have designed arginine mimetics for specific and high affinity molecular recognition by coupling protected guanidino acids to alcohol and amine nucleophiles. Protected guanidino acids of Gly, Phe, Val, and Leu were readily synthesized from methyl esters of alpha-amino acids by guanylation of the amine with bis-boc-thiourea and Mukaiyama’s reagent.  Protected guanidino acids, with a free carboxylic acid for coupling to nucleophiles, were generated by saponification of the methyl ester using LiOH.  Arginine mimetics were synthesized by coupling protected guanidino acids to hydroxyl and amino groups to generate complex alpha-substituted guanidiniums.  Molecules containing alpha-guanidino acids were applied to specific protein and RNA recognition. This work supported in part by the National Institute of Health and the Howard Hughes Medical Institute Undergraduate Science Education Program.

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 University of Delaware's Women Scholars Program. The HHMI Program, the Beckman Scholars Program, Charles Peter White Fellowships, the Biomedical Research Infrastructure Network (BRIN) Program, a USDA Grant, and the Undergraduate Research Program supported research by the students.

Trip Photos. Click on any image for a full-sized picture.

UD alums Jennifer Paulson '99, Cory Ocasio '00, and John Dueber '99 all BS Biochemistry.

San Francisco from the Golden Gate Bridge.

East Coast Tourists at Golden Gate with San Francisco in the back ground.


Walking tour of Chinatown in the rain.
Ghirardelli Chocolate Factory in the rain.

Blue and Gold Line Ships in San Franisico

Liang Kang, Aggie Bielska, and Kristen Reese talking to 1992 Nobelist  Edmond Fischer who discovered protein phosphorylation.

Aggie Bielska, Jess Hall, and Al Smith with 1959 Nobelist Arthur Kornberg discoverer of DNA polymerase.

Aggie Bielska, Jess Hall, and Al Smith with 1959 Nobelist Arthur Kornberg discoverer of DNA polymerase.

UD students at the ASBMB Undergraduate Poster Competition.
UD awardees (1,3,4,5 front row, 3 in back row) with Tom Cech, President of HHMI

UD Students who received Honorable Mentions in the ASBMB Poster with Tom Cech and others.

Colorful seafood at Fisherman's Wharf.

Front Range of the Rocky Mountains from 32,000 feet.

Aggie, Brett, Dr. Laverty, and Eric at Thai restaurant

Before or after the swim?

Yes, They actually did go swimming in the Pacific in March!
Seals at Pier 39.

Hal White with Marilee Benore-Parsons (UD'86), a former graduate student of his.

At Lefty O'Doules in the evening.

Dinner out with Dr. Usher.

Alumni Dinner
Ron Gomes talking with Dave Usher at the UD alumni dinner.

Alumni Dinner

Alumni Dinner

Alumni Dinner

UD Students talking to 1992 Nobelist Edmond Fischer.

Waiting to depart PHL.

Waiting to Depart SFO

SFO from the air.

ASBMB Undergraduate Poster Competition in San Diego 2005
Return to HHMI Undergraduate Home PageUniversity of Delaware HHMI Home Page
Created 2 January 2006,  revised 14 April 2006 by Hal White [halwhite at]
Copyright 2006, Harold B. White, Department of Chemistry and Biochemistry, University of Delaware