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The University of Toledo Department of Bilogical Sciences

WOLFE HALL (Room 3246) Saturday, April 21, 2001


Chart Abstracts 6th URS 6th URS Photos  UT Biological Sciences

(click on the presenter name for abstract)



Presentation Title


Dr. Patricia Komuniecki



Plenary Lecture- "Evolution-The Movie" Dr. Isabel Novella (Medical College of Ohio)

Session I - Elizabeth Rex, Moderator


Steven M. Ariss, Jr.

Analyzing the domains of plakoglobin necessary for cross-talk between adherens junctions and desmosome formation


D’Anna N. Brown

Analysis of protein-protein interactions and iron-binding 
properties of the LLS1 protein from maize


Christina M. Cain

The effects of a gene II frameshift mutation of symptom 
severity in CaMV strain W260


Janet M. Cullen

Cadherin processing


Amanda J. Graham

Progress in cloning C. elegans vab-10 gene


Pizza lunch

Session II - Katy Smith, Moderator


Yara Moubayed

The effects of dexamethasone on E-cadherin and vimentin expression


Troy Puckett

Exploring the effects of the neuropeptide AF2 and 5-HT 
on muscle metabolism in the parasitic nematode Ascaris suum.


Louisa R. Seifert

Tissue magnesium and Parkinson’s disease


Melissa C. Srougi

The study of memory function in an animal model of Alzheimer’s disease


Dustin A. Chase

Physiological and molecular analyses of the maize zebra necrotic 1 (zb1) locus


Douglas S. Sturtz

The translational transactivator domain of the cauliflower 
mosaic virus interacts with the full length gene VI product




Awards ceremony

Abstract 6th URS

Amanda Graham
Progress in cloning C. elegans vab-10 gene
Advisor: Dr. John Plenefisch
Department of Biological Sciences

Mutations in the mua genes of the nematode Caenorhabditis elegans cause animals with normal muscle differentiation to lose attachment between the skeletal muscles and the body wall, resulting in paralysis.  Specifically, the vab-10 mutation results in detachment of muscle from the body wall epidermis of the animal.  The plasmid ZK1151, containing genes for plectin, kakapo, and a third uncharacterized protein partially rescues vab-10 mutants.  Isolation of each of these genes is necessary to determine which is responsible for vab-10 rescue, ultimately identifying one as vab-10.  Sub clones derived from ZK1151 containing one or more of the encoded genes are being constructed using restriction enzymes.  The derivatives are then microinjected into vab-10 mutants and monitored for rescue.  Due to the complexity of the molecular locus results are still pending.  However, based on published RNAi data, it is predicted that the kakapo gene will be identified as vab-10.

Christina Cain
The Effects of a Gene II Frameshift Mutation of Symptom Severity in CaMV Strain W260
Advisor: Dr. Scott Leisner
Department of Biological Sciences

CaMV is a plant DNA pararetrovirus.  It contains seven genes that code for seven distinct proteins.  The gene of interest for this study is gene II that encodes for an 18 kDa protein.  This study was designed to determine whether disruption of gene II, the aphid transcription factor (ATF), will decrease the virulence of the Cauliflower Mosaic Virus (CaMV) strain, W260.   Currently, it is believed that the primary function of the protein encoded by gene II (PII) is for transmission of the virus via aphids.  However, it is thought that it could play a role in viral infectivity as well.  To determine the effect gene II has on the infectivity of CaMV, gene II must be made nonfunctional.  This was done by creating a frameshift mutation in gene II.  The mutant, as well as the wild-type strain of W260 were then introduced to their host, turnip plants, and allowed to propagate.   It was thought that the mutant would produce symptoms much less severe than the wild-type.  However, the results suggest a more complex interaction between PII and symptom formation.

D'Anna Brown
Analysis of Protein-Protein Interactions and Iron-Binding Properties of the LLS1 Protein from Maize
Advisor:  Dr. John Gray
Department of Biological Sciences

Mutations of the lls1 (lethal leaf spot 1) gene cause necrotic leaf spots (lesions) in maize.  Because the lack of a functional lls1 in maize causes these lesions, it has been hypothesized that the LLS1 protein functions to prevent or localize cell death.  An ortholog of LLS1 called ACD1 (Accelerated Cell Death 1) exists in Arabidopsis.  The predicted amino acid sequence of LLS1 reveals the presence of two iron-binding motifs, a Rieske-type and a mononuclear iron-binding site, which are highly conserved in several bacterial and plant enzymes of diverse functions.  Of these enzymes, the three-dimensional structure of naphthalene 1, 2-dioxygenase is known, and based on its a3b3 hexameric structure, it is hypothesized that LLS1 may interact with other proteins or with itself.  A two-hybrid screen was performed using ACD1 as the bait construct and an Arabidopsis cDNA prey library.  No positive interacting proteins were recovered.  In addition, maize LLS1 was used both as bait and prey to test of it interacts with itself.  Growth was not observed in the absence of leucine.  These two results suggest that LLS1 does not interact with itself and probably interacts only weakly with a partner protein, if one exists. In order to test that LLS1 does in fact bind iron we have begun to use site-directed mutagenesis to change three key histidine residues in the predicted iron binding motifs (H117A, H138A, H237A).  Using these constructs we will examine the predicted iron binding properties of LLS1.

Doug Sturtz
The Translational Transactivator Domain of the Cauliflower Mosaic Virus Interacts with the Full Length Gene VI Product
Research Advisor:  Dr. Scott Leisner
Department of Biological Sciences

Plant viruses contribute to billions of dollars in crop losses every year. For viruses to cause damage, viral gene products have to interact with each other.  In order to study viral protein-protein interactions, we examined Cauliflower mosaic virus (CaMV).  CaMV is useful for the study of protein-protein interactions because the viral DNA is easily manipulated using restriction endonucleases and cloned into bacterial plasmids.  The gene VI product (P6) controls the expression of the other CaMV genes by regulating their translation.  This process is called translational transactivation and is mediated by a specific region of P6 termed the TAV domain.  The sequence coding the TAV domain of P6 was generated by the polymerase chain reaction and inserted into a yeast-two hybrid vector that was propagated in E. coli.  The yeast-two hybrid system permits protein-protein interactions to be detected by allowing growth on leucine-deficient medium.  By using the yeast-two hybrid system, we have demonstrated that the TAV domain interacts with the full length gene VI product.  This suggests that a binding site exists within the TAV domain.  This binding site may be essential for gene VI product activity.  Therefore, if this interaction is interfered with, this viral infection may not take place.

Dustin A. Chase
Physiological and Molecular analyses of the maize zebra necrotic 1 (zb1) locus
Advisor: Dr. John Gray
Department of Biological Sciences

Certain mutant alleles within maize cause phenotypic zebra necrotic banding along the leaf.  Among these mutants, zb1 was identified within a mutator active population and proved novel from associated phenotypic mutants zn1 and zn2 by allelic testing.  A candidate clone was isolated from a co-segregating population and sequenced.  Using a reverse genetics approach, confirmation that the correct gene has been cloned is currently underway.  Physiological studies have uncovered zb1 as having an environmentally dependent phenotype in response to diurnal cycles.  zb1 mutants grown in four-hour diurnal cycles exhibit enhancement in banding number and decreased bandwidth.   In addition, zb1 mutants, grown under etiolated conditions, display rapid death of immature leaves on exposure to light.  Utilizing comparative biological analysis, the predicted sequence of zb1 shares strong homology to a putative K+ channel protein found within the BAC clone F15J5 in Arabidopsis.  The putative amino acid sequence contains two conserved pore regions, called P-domains, coded by TxGYGD, found in all K+ channels.  In addition, the putative K+ channel also contains a cyclic NMP binding site, enabling gated signaling of the channel in response to pH constraints.  zb1 is hypothesized to play a role in regulating cellular homeostasis specifically in diurnal fashions.  We propose that the putative channel has a light adaptive function that plays a protective role in chloroplasts during the transition to the stress of incident light.  However, further research is needed since K+ channel control over cellular processes is not clearly understood in plants.    

Janet M. Cullen
Cadherin Processing
Advisor: Dr. Keith Johnson
Department of Biological Sciences

The transmembrane glycoproteins referred to as classical, or type I cadherins, play a primary role in cell-cell adhesion.  In conjunction with several proteins, including p120, b-catenin, and a-catenin, cadherins relay extracellular messages to the actin cytoskeleton, evoking morphological responses.  These changes are involved in such processes as tissue differentiation and cell division.  However, cadherins must undergo a series of processing events between translation of the protein and its insertion into the plasma membrane.  One such processing event involves cleavage of the proregion, which must occur before the cadherin is able to function in cell-cell adhesion.  Anti-proregion antibodies had previously been developed in the lab, and were used to track the addition of p120, b-catenin, and a-catenin, in relationship to the presence of the proregion.  The results suggest that all three proteins are in fact present, prior to the removal of the proregion.  These findings may further aide in studies which attempt to elucidate the steps of cadherin processing, resulting in further understanding of cadherin function or regulation.

Louisa Seifert
Tissue magnesium and Parkinson's Disease
Advisor: Dr. Lawrence Elmer
MCO Dept. of Neurology

Background: Parkinson’s Disease (PD) is a neurodegenerative disorder caused by degeneration of nerve cells in the substantia nigra, which afflicts more than a million people in the United States.  Magnesium is the second most common divalent cation in the human body and serves to modulate the response of NMDA receptors, which modulate the excitatory effects of glutamate. Clinical experience suggested that tissue magnesium levels were related to responsiveness to drug therapy in PD.  In addition, brain magnesium in post-mortem studies also suggested levels below that seen in normal controls. 
Procedure: Participants were recruited during normal office visits.  Forty participants, including PD patients and age-matched controls, used sterile swabs to collect buccal cells for analysis.  Participants with PD were asked to rate the effectiveness of their current medical treatment.  Atomic absorption spectrophotometry and protein analysis were used to determine the concentration of magnesium per milligram of protein in the samples.  Results: There was no correlation between responsiveness to drug therapy and tissue magnesium.  Interestingly, PD patients had significantly more tissue magnesium in their buccal swab samples than control patients.  Future experiments will attempt to confirm the presence of high peripheral tissue magnesium in PD compared to documented hypomagnesium levels in the brains of PD patients. Further studies will utilize this technology to the examination of tissue magnesium levels in other neurodegenerative diseases, including Huntington’s and Alzheimer’s Diseases.

Melissa C. Srougi
The study of memory function in an animal model of Alzheimer's disease
Advisor: Dr. William Messer, Jr
UT Department of Medicinal Chemistry and Biology

It has been observed that Alzheimer’s disease (AD), a common disease that afflicts the elderly, leads to cholinergic neuron loss.  This loss causes a decrease in the production of a neurotransmitter involved with learning and memory, acetylcholine.  M1 muscarinic receptors, found in the cortex and hippocampus, have been isolated to combat this problem.  Studies show that by selectively activating these receptors the concentration of acetylcholine in the body will increase and reverse memory deficits.  Two selective M1 muscarinic agonists, CDD-102, and xanomelin are administered to transgenic mice expressing a mutant human amyloid precursor protein (hAPP).  Representational memory function is tested using a paired-run alternation task in a T-maze. After training, performance is tested at 3-5 months of age, and again at  6-9 months of age.  During testing at 6-9 months of age, CDD-102 and xanomelin are administered, and the mice’s performance in the T-maze is documented.  Finally, choline acetyl transferase activity and genotyping is determined.  Animals trained at 6-9 months of age showed poor learning <70%. The mice never learned the task so data from the drug trial is inconclusive.  This may infer a critical age for hAPP mice to be trained before they lose the ability to learn.

Steven M. Ariss, Jr.
Analyzing The Domains of Plakoglobin Necessary for Cross-Talk Between Adherens Junction and Desmosome Formation
Advisor: Dr. Jani E. Lewis
Department of Biological Sciences

Epithelial cells have both adherens junctions and desmosomes which bind one epithelial cell to another.  The adherens junction is composed of a transmembrane classical cadherin (E-cadherin and/or P-cadherin in epithelial cells) linked to either β-catenin or plakoglobin, which is linked to α-catenin, which is linked to the actin cytoskeleton.  The desmosome is composed of transmembrane proteins (desmogleins and desmocollins) that are linked to the intermediate filament cytoskeleton, via plakoglobin and desmoplakin.  Plakoglobin is the only protein that occurs in the cytoplasmic plaques of both adherens junctions and desmosomes.  Blocking studies have shown that the ability of the cells to organize the desmosomal proteins into a functional structure depends upon a cell’s ability to first organize an adherens junction.  Although adherens junctions can form in the absence of plakoglobin, making use of only β-catenin, such junctions cannot support the formation of desmosomes.  Furthermore, experiments conducted with an epithelial cell line not expressing the classical cadherins showed that plakoglobin must be linked to E-cadherin in adherens junctions in order for desmosome formation to occur.  The purpose of this project was to determine what parts of plakoglobin must be linked to E-cadherin to get desmosome formation.  

Troy Puckett
Exploring the effects of the neuropeptide AF2 and 5-HT on muscle metabolism in the parasitic nematode Ascaris suum.
Faculty Advisors: Dr. Richard Komuniecki, Dr. Patricia Komuniecki, Dr. Sally Harmych
Department of Biological Sciences

Parasitic nematodes pose major global problems including health related problems in humans and financial problems regarding crops and livestock.  For these reasons, efforts are being made to develop more effective chemotherapeutic treatments.  Some prospective targets for such anthelminthic activity are the neuropeptide controlled metabolic pathways of nematodes.  Ascaris suum is a parasitic nematode of swine which serves as an ideal experimental model for such research because of its size and availability.  These studies were performed to examine the effects of the neuropeptide AF2 and 5-HT on the production of cAMP and the rate of glycogenolysis in A. suum.  body wall muscle was powdered and homogenized, and the homogenized samples were assayed for levels of glycogen, cAMP, and protein.  It was discovered that AF2 stimulates the production of cAMP and the process of glycogenolysis.  It was also found that, in contrast to published data, 5-HT has no effect on cAMP levels or glycogenolysis. 

Yara Moubayed
The Effects of Dexamethasone on E-cadherin and Vimentin Expression 
Advisor: Dr. Keith Johnson
Department of Biological Sciences

In epithelial tissues, the actin cytokeletons of adjacent cells are linked to each other via cellular structures called adherens junctions.  Cadherins are the transmembrane components of adherens junctions and are important not only in cell adhesion but also cell sorting.  Most cells express at least one type of cadherin, although some cells express two or more different types.  Other cell-adhesion structures, such as desmosomes and hemidesmosomes, form membrane associations with the intermediate filaments of the cytoskeleton.  Numerous studies have demonstrated that increased expression of the intermediate filament, vimentin, in carcinomas correlates with malignant potential.  In addition, loss of cadherins has also been associated with tumor cells and metastasis.  This project explored the relationship between the dexamethasone-induced down regulation of E-cadherin and the expression of vimentin in epithelial carcinoma cells.
6th URS Photos

Participants of the 6th annual URS
6th Participants
Standing L>R: D'Anna Brown, Justin Foreman, Douglas Strurtz, Dr. Isabella Novella (plenary speaker), 
Louisa Seifert, Melissa Srougi, Christina Cain, Dustin Chase, Amanda Graham, Yara Moubayed, 
and Troy Pickett.  Seated L>R: Steven Ariss and Dr. Emilio Duran (symposium director).  
Janet Cullen is not pictured.
Winners of the 6th annual URS
First Place - Janet Cullen and Melissa Srougi
Second Place - Troy Puckett
Third Place - Dustin Chase

Audience at the 6th annual URS
6th Audience

last updated 29 Dec 2005
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Last Updated: 8/10/18