Factors affecting gene conversion in Arabidopsis thaliana

Alexandra L. Bey

Research Advisor:  Dr. Gregory P. Copenhaver

Research Mentor:  Luke Berchowitz

My project is to observe the effects of two different genes on gene conversion in the plant Arabidopsis thaliana. Gene conversion is the non-reciprocal transfer of DNA between chromosomes. Because gene conversion occurs every time meiotic recombination occurs, understanding this process will augment understanding of crossing-over, which is an important source of genetic variability. In order to assess the role of the genes MUS81 and MSH4 on gene conversion, I work with plants mutant for the quartet gene. The pollen of quartet mutants remains fused in a tetrad of meiotically related gametes. This configuration is useful for tetrad analysis, which I perform using plants carrying markers derived from the fluorescent proteins of jellyfish. Having created plants which bear a fluorescent allele and a non-fluorescent allele due to an induced point mutation, I use a microscope to detect gene conversion events where fluorescence is restored to the non-fluorescent marker.

Environmentally Dependent Hybridization Preferences in Spadefoot Toads

Christine Bookhout

Research Advisor:  Dr. Karin S. Pfennig

When two species come into secondary contact after a period of evolution in isolation, they may evolve mating behaviors that prevent the formation of unfit hybrids (a process called reinforcement). When hybridization is beneficial for one species, however, reinforcement may be impeded. I evaluated whether female spadefoot toads preferentially mate with heterospecifics under conditions where they benefit by hybridizing. Female Spea bombifrons potentially increase their fitness by hybridizing with S. multiplicata in fast-drying ponds, because hybrid offspring develop quickly and are more likely to escape from highly ephemeral breeding pools.  By contrast, S. multiplicata females reduce their fitness by hybridizing because their hybrid offspring develop more slowly than pure S. multiplicata tadpoles. I tested whether S. bombifrons females from sympatry are more likely to alter their conspecific versus heterospecific mating preference under low water conditions as compared to both sympatric S. multiplicata females and allopatric S. bombifrons females.

Genetic and Molecular Analyses of dLSM10, an U7snRNA Unique Protein in Drosophila

Ashmita Chatterjee

Research Advisor:  Dr. Robert J. Duronio

Research Mentor:  Ashley Godfrey

Cell cycle regulated histone biosynthesis is an essential aspect of genome duplication during proliferation, and is controlled primarily by the cell cycle regulated biosynthesis of histone mRNAs. The U7snRNP is necessary for histone pre-mRNA processing and has been shown to contain two unique proteins, Lsm10 and Lsm11, named for being Like-Sm proteins. U7snRNA contains a unique Sm site which is believed to recruit Lsm10 and Lsm11 specifically to the U7 particle. My specific research project is to characterize Lsm10 mutants. I hypothesize that Lsm10 is required for histone pre-mRNA processing, and therefore Lsm10 mutants should phenocopy U7 snRNA mutants, since Lsm10 binding is vital for the role U7snRNP plays in histone pre-mRNA processing.  To determine if Lsm10 mutants have this same phenotype, I will analyze existing Lsm10 mutant flies for Lsm10 protein expression and for the histone mRNA misprocessing and developmental phenotypes.

Oxytocin Receptor Activation and Exposure to Maternal Behavior in Rat Pups

Nancy Helen DeMaria

Research Advisors: Cort A. Pedersen, MD and Dr. Maria Boccia

Departmental Sponsor:  Dr. Sabrina Burmeister

Oxytocin is a peptide hormone produced by the hypothalamus and released by the posterior pituitary.  It is implicated in many aspects of mammalian maternal and affilitative behavior.  The purpose of this study was to determine if the stimulus of maternal behavior activates Oxytocin receptor neurons in certain critical areas of the pup brain.  On postnatal day 8 of life, some pups were removed from their mothers for a period of time and then returned.  Through observing differences in the activation of an immediate early gene product, cfos, it is hypothesized that those pups that received resurgence in maternal behavior will show more cfos immunoreactive Oxytocin neurons.  Behavioral analyses quantify the amount of maternal behavior for each mother.  The neurobiology of this phenomenon will give further insight into the negative effects of deficient maternal-offspring relationships such as child abuse and neglect.

Differential Gene Expression in Hybrid Species of Spadefoot Toads

Kelly Haisley

Research Advisor:  Dr. Karin Pfennig and Dr. Corbin Jones

In this research, we are investigating hybrid incompatibilities in the Spea genus of spadefoot toad with respect to mating behavior and sterility.  As part of the investigation, we are assaying gene expression levels in hybrids using microarray technology to pinpoint potential candidate genes that are expressed normally in parental groups but differentially in the species hybrids.  To verify that the expression differences observed are real, we are using quantitative RT-PCR.  However, to do this, candidate genes must first be cloned out of Spea which will be done via the creation of a cDNA library.

A chemical genomics approach to study signaling cascades in Arabidopsis thaliana

Will Hannah

Research Advisor:  Dr. Alan Jones

Chemical genomics is a powerful method to study signaling cascades.  This technique uses small chemicals to disrupt the function of genes and proteins.  After screening a large chemical library, thirteen compounds were selected that caused phenotypes in the model organism Arabidopsis thaliana.  Four compounds were then identified that inhibited primary root development and stimulated lateral root development in wild-type seedlings.  One of these chemicals, designated WH7, is particularly potent, acting at a concentration of 5 nM.  An EMS screen was conducted to identify mutant seedlings resistant to WH7.  The resistant seedlings developed aerial rosettes, a phenotype associated with mutations in the auxin pathway gene CAND1.  Additionally, CAND1 mutants showed resistance to WH7.  WH7 was further characterized by utilizing the auxin-responsive DR5::GUS construct and GFP reporter lines to observe its effects on the expression of tissue-specific genes.  By studying the effects of WH7 and other chemicals, the signaling pathways through which these chemicals act can be better understood.

The Role of Suppressor of sable (Su(s)) in Nuclear RNA Metabolism

Cedric Hunter

Research Advisor:  Dr. Lillie Searles

The Searles lab is interested in the control of pre-mRNA metabolism.  Our research is focused on the Drosophila Suppressor of sable (Su(s)) protein. This RNA binding protein appears to promote the rapid degradation of aberrant RNA transcripts as they are being synthesized.  Among the Su(s) targets are noncoding RNAs produced by tandemly repeated elements (transposons) that are located near Hsp70 genes.  In one of these elements there is a duplicated Hsp70 promoter driving expression of the transposon sequences during heat shock.  We propose that particular sequences in these non-coding RNAs tag them for degradation by a Su(s) dependent pathway.  My experiments are designed to test this hypothesis and identify the sequences that are responsible for this effect.  These results will shed light on the mechanisms that cells use to inhibit the accumulation of aberrant transcripts which could have negative effects on cellular activity.

Understanding Checkpoint Response and DNA Replication in Drosophila melanogaster:

Sumreen Hussain

Research Advisor:  Dr. Jeff Sekelsky

Research Mentor:  Jan LaRocque

The cell cycle is controlled by checkpoint kinases which regulate the progression of the cell cycle.  In Drosophila, the kinase ATR is required for the G2 to M checkpoint and is encoded by the gene mei-41.  When mei-41 mutants also have the mutation E(mus304), a rough eye phenotype results.  The Sekelsky Lab found that E(mus304) is a mutation in the gene DNApolα-180, which encodes the catalytic subunit of DNA polymerase.  The goal of my project is to screen for other genes that interact with mei-41 or E(mus304) using the rough eye phenotype as a marker for this interaction.  Identifying and characterizing other genes that interact with mei-41 or E(mus304) may provide a further understanding of the interaction between cell cycle control and DNA replication which is exhibited through the rough eye phenotype seen in mei-41; E(mus304) mutants.

Is Hotter Better? Understanding the Genetic Basis of

Matthew Kasold

Research Advisor:  Dr. Christina Burch

Research Mentor:  Jennifer Knies

Although laboratory evolution experiments have been studied extensively in microorganisms, less is known about the genetic basis of thermal adaptation. Trade-offs and specialization can occur in viral populations to adapt to these changes by an increase in stability or by an increase in flexibility. In order to explore these mechanisms, I adapted the bacteriophage G4 to four novel temperatures, two higher and two lower than G4’s optimal range. Identifying these patterns of adaptation improves our ability to evaluate the risks of disease emergence in humans and the threats of population extinctions due to global warming. Vaccine development strategies can also be modeled after this so that it can be readily made in lab, but weakened at higher (body) temperatures.

Cloning the cytokinin-insensitive mutant cin2 and the development of transgenic ACS lines in A.thaliana

Adrian Lazo

Research Advisor:  Dr. Joe Kieber

Research Mentor:  Hyun Sook Chae and Maureen Hansen

Cytokinin is one of several plant hormones playing important roles during plant development. One such function is the induction of the gaseous plant hormone, ethylene, which has been shown to influence a number of developmental and physiological processes including germination, fruit ripening, leaf and flower senescence, and a variety of stress responses.  Cytokinin functions in this capacity through the induction of ACC synthase (ACS), an enzyme that catalyzes the first committed step in ethylene biosynthesis. However, the complete mechanism underlying this regulation is not fully understood. In order to aid in the further elucidation of these pathways, my research has focused on two main projects. The first is the cloning and characterization of the cytokinin-insensitive (cin) mutant cin2 in Arabidopsis. The second is the development of transgenic plant lines with inducible promoters and epitope tags for a number of the ACS isozymes to examine their post-transcriptional regulation under various conditions.

Consequences of Unprotected Chromosome Ends: investigating the effects of cku-80, pot-2 and mrt-2 on C. elegans telomeres

Teresa Lee

Research Advisor:  Dr. Shawn Ahmed

Research Mentor:  Julie Boerckel and Mia Lowden

Telomeres are protective sequences of DNA at chromosome ends that shorten with each cell division; when they reach a critical length, they signal cells to enter senescence.  In germ cells, the enzyme telomerase restores their length, allowing cells to divide indefinitely.  Each telomere has a ssDNA overhang that tucks back into the dsDNA, forming a protective cap called the T-loop; this helps regulate access to telomerase.  Cells can escape senescence or death by developing mutations that affect the telomere, as is the case for many cancer cells.  CKU70 and CKU80 are two proteins that bind to the T-loop. In the model organism C.  elegans, mutant worms lacking these proteins seem to have normal telomeres.  I hypothesized that these proteins have no effect overhang length.  To test this, I developed a dot blot assay to quantitate overhangs in several mutant strains, including  POT-1, POT-2, and POT-3 which may also bind to the T-loop.  I used immunofluorescence staining to determine where POT and related MRT proteins are located within the germlines of wildtype and mutant strains.

Regulation of CFTR recycling by SNX27, an endosomal adapter  protein

Patrick Lyons

Research Advisor:  Dr. Sharon Milgram

Research Mentor:  Dr. Mark McDermott

Departmental Sponsor:  Dr. Frank Conlon

Cystic fibrosis is an inherited disease affecting around 30,000 Americans today.  It is caused by defects in the CFTR protein, which  regulates ion transport across epithelial cells in tissues including  the airway and GI tract.  Our lab discovered a novel protein, sorting  nexin-27 (SNX-27), that interacts with CFTR.  SNX-27 is a member of a  group of proteins that regulate the recycling of membrane bound proteins, and it is hypothesized that SNX-27 is involved in regulating the endocytic trafficking of CFTR.  My work aims to determine the role of the various domains of SNX-27 as they relate to the protein's expression, localization, and interaction with CFTR.

The Role of Androgens in the Risky Calling Behavior of Male Túngara Frogs

Andrea Martin

Research Advisor:  Dr. Sabrina Burmeister

Research Mentor:  Mukta Chakraborty

The male túngara frog can increase the complexity of its call from a simple "whine" to a complex "whine chuck." The complex call is more attractive to both female túngara frogs and frog-eating bats, thus making túngara frogs an ideal model system for the study of sexual selection. I examined the effect of androgens on the production of this risky, complex call. I assessed this effect using hormone manipulations and behavioral tests (vocalization inductions). I also validated the hormone manipulations by examining the circulating plasma concentrations of androgens and by quantifying the expression of androgen receptor genes in the brain of breeding males. To examine sex differences, I also compared androgen receptor expression in brains of males and females.

The Role of PPARγ in Vascular Remodeling

Dane Meredith

Research Advisor:  Dr. George Stouffer

Research Mentor:  Dr. Susan Smyth

Departmental Sponsor:  Dr. Victoria Bautch

The PPARγ protein is an important nuclear transcriptional activator with a well characterized role in lipid and glucose metabolism. PPARγ is the molecular target of the TZD family of diabetes drugs. TZDs act as agonists for PPARγ activity, which subsequently reduces blood glucose levels. However, the benefits of TZDs do not stop there. Recent clinical studies suggest that TZD therapy reduces the prevalence of coronary artery disease. This suggests that PPARγ plays a role in preventing atherosclerosis. The goal of my research is to characterize the relationship between PPARγ and atherosclerosis. Furthermore, my research will investigate some of the possible mechanisms behind this relationship. I will be using surgical models of atherosclerosis in PPARγ deficient mice to see if there is a difference in vascular remodeling between deficient and wild-type mice. Furthermore, bone marrow transplants and smooth muscle cell cultures will be employed to try and determine the mechanism behind PPARγ activity.

Steroid sulfotransferase in cytokinin primary response and Arabidopsis development

Jared Owen

Research Advisor:  Dr. Joseph Kieber

Research Mentor:  Dr. Bridey Maxwell

Special Thanks to:  Jenn To

My research focuses on one way in which the hormone cytokinin influences plant growth and development through the induction of a steroid sulfotransferase gene (SST1).  I have shown that SST1 plays a role in the regulation of root elongation and may act by influencing the brassinosteroid hormone pathway.

Verification of Somatodendritic Dopamine Release in the Ventral Tegmental Area Using Fast-Scan Cyclic Voltammetry

Lauren Parker

Research Advisor:  Dr. R Mark Wightman

Departmental Sponsor:  Dr. Stephen Crews

Dopaminergic neurons originating in the ventral tegmental area (VTA) of mammalian brains synapse on the limbic system and frontal cortex.  The stimulation of these neurons is implicated in pleasure, reward, addiction, and aggression.  Generally, neurotransmitter release occurs at the terminal boutons of a stimulated neuron; however, our research focused on dopamine release from the soma (cell body) of these neurons.  Using in vivo fast-scan cyclic voltammetry we were able to detect a transiently released neurotransmitter in the VTA following stimulation of the medial forebrain bundle in anesthetized rats.  We attempted to verify the identity of our signal using a set of five analytical criteria.  Further histological experimentation remains to be completed to confirm our signal as dopamine.  Dopamine released at the soma may be used to self-regulate these neurons at D2 (dopamine) autoreceptors on the dendrites.  These results further our understanding of the dopamine reward pathway.

Microtubule binding and kinetochore localization in Ndc80

Jessica Polka

Research Advisor:  Dr. Ted Salmon

Research Mentor:  Jennifer G. DeLuca (now at Colorado State)

The Ndc80 complex is a group of four proteins – Ndc80 (in humans, Hec1, for Highly Enhanced in Cancer cells), Nuf2, Spc24, and Spc25 – that localize to the outer plate of the kinetochore, a structure of proteins on chromosomes that serves as a docking site for microtubules, which carry forces that separate genetic material into two new daughter cells during mitosis. The Ndc80 complex is required for establishing stable kinetochore-microtubule attachments and ensuring accurate chromosome segregation during cell division. Since depleting the Hec1 protein has been demonstrated as a potentially viable anti-tumor therapy, an understanding of the functionality of the entire Ndc80 complex will be crucial to development of inhibitory drugs.  This project aims to identify residues on the Spc24/25 dimer important for kinetochore binding through microinjection of fluoresecently labeled recombinant Ndc80 complexes carrying point mutants on these proteins. Furthermore, in vitro binding studies involving a recombinant region of Hec1 will reveal the kinetics and stoichiometry of Ndc80’s interaction with microtubules.

Novel Regulators of Diaphanous-Mediated Smooth Muscle Cell Differentiation

Ashley Pridon

Research Advisor:  Dr. Chris Mack

Research Mentor:  Dean Staus

Departmental Sponsor:  Dr. Vicki Bautch

Smooth Muscle Cell (SMC) differentiation is vital for vasculature development, and changes in SMC phenotype contribute to the pathogenesis of multiple cardiovascular diseases. The Diaphanous 2 (Dia2) protein potently stimulates actin polymerization in SMCs, and Dia2-dependent changes in actin dynamics enhance SMC-specific gene transcription by promoting the nuclear localization of myocardin-related transcription factors.  My project focuses on two proteins that interact with Dia2: Histidine Triad Protein 2 (HINT2) and Ubiquitously Expressed Transcript (UXT). Characterization of these proteins’ effects on Dia2 signaling/SMC gene transcription will increase our understanding of vessel development as well as the progression of cardiovascular disease.

Plasticity in the Central Auditory System: A Study of the Expression of nAChR-α7 in the Cochlear Nucleus and Inferior Colliculus in a Mouse Model of Age-Related Hearing Loss

Eveleen Randall

Research Advisor:  Dr. Paul Manis

Research Mentor:  Heather O’Donohue M.S.

Departmental Sponsor:  Dr. Sabrina Burmeister

In age-related hearing loss (presbycusis), electrical signals from the inner ear gradually weaken.  Some neurons in the brain try to compensate for this lost input by altering their signaling mechanisms. Studying receptor expression in components of the central auditory pathways of the brain can reveal alternative signaling mechanisms and identify plasticity processes following hearing loss.  Past research shows that the cholinergic system attempts to compensate for lost electrical innervations resulting from hearing loss.  My research aims to characterize the expression of the nicotinic acetylcholine receptor alpha 7 subunit (nAChR-α7) in the cochlear nucleus and inferior colliculus, two regions involved in auditory processing.  Preliminary results indicate that this receptor may be up-regulated after hearing loss in mouse models of presbycusis.  This study will further our understanding of the neuronal mechanisms used to compensate for lost electrical innervations and perhaps suggest different approaches to restoring auditory function and perception after hearing loss.

Histone Misexpression and its Impact on Chromatin Formation

James Raymond

Research Advisor:  Dr. Robert Duronio

Research Mentor:  Harmony Salzler

Histones are a set of proteins important in the packaging and organization of eukaryotic DNA into chromatin.  The structural character of chromatin has significant bearing on the expression of associated genes and hence, plays an important role in normal development and function of the cell. Histone biosynthesis occurs during the S-phase of the cell cycle to accommodate for newly replicated DNA.  At this time, newly synthesized histones are deposited on DNA and chromatin is formed.  Histone biosynthesis in metazoans is tightly coupled to S-phase by the regulation of mRNA transcripts.  Histone mRNAs are unique in that the 3’ ends of mature transcripts are not stabilized by polyadenylation, but by a conserved stem-loop.  The purpose of my research is to examine the effect of histone expression outside of S-phase by introducing polyadenylated histone mRNA transcripts in replicating cells. We believe that expressing histones outside of S-phase will lead to pathologies in development due to the effects of abnormal histone deposition on chromatin structure and function.

Manipulation of auxin response in developing flowers

Emily Rosowski
Research Advisor:  Dr. Jason Reed

Research Mentor:  Miin-Feng Wu

In plants, the hormone auxin regulates development through transcription factors called ARFs.  In the absence of auxin, Aux/IAA proteins inhibit ARFs, preventing the activation or repression of genes by the ARFs.  In the presence of auxin, the Aux/IAA proteins are broken down, freeing the ARFs from inhibition.  Our goal is to understand whether this auxin-Aux/IAA-ARF system controls flower development.  Flower development is important because flowers are the mechanism a plant uses to make seeds, and seeds are important for agriculture and oil production.  To approach this question, I misexpressed genes that would perturb auxin response in specific regions of the flower.  I used genes encoding enzymes that directly affect auxin levels, a microRNA that targets certain ARFs for degradation, and mutated Aux/IAA proteins with increased stability.   Manipulations of this regulatory system may cause floral organs to arrest development or to develop aberrantly.

The Mapping and Characterization of an Arabidopsis Mutant

David Rybnicek

Research Advisor:  Dr. Jeff Dangl

Research Mentor:  David Hubert

When bacteria infect Arabidopsis thaliana, they secrete avirulence (avr) proteins into the plant cell.  This plant can recognize these proteins through the action of plant Resistance (R) proteins.  This interaction is the first step towards mounting a defense response.  The mutant plant line in this study is compromised in its ability to recognize and respond to several avirulence proteins, and I have data that suggest that the function of several R genes is affected.  We believe this phenotype to be the result of a mutation in a novel plant gene involved in disease resistance.  The aims of this project are to map this mutation to a gene in the Arabidopsis genome and to characterize the mutation’s effects on the activity of several R genes.

Armadillo regulation in Drosophila

Daniel Schneider

Research Advisor:  Dr. Mark Peifer

Research Mentor:  Dr. David Roberts

The Wingless (Wg) signaling pathway is very important in normal development of Drosophila and mammals, and mutations that arise in this highly conserved pathway are responsible for 95% of all colon cancer cases. The key effecter protein of this pathway is Armadillo (Arm). Arm is a transcriptional co-activator that regulates genes involved in cell proliferation.  Arm is constitutively transcribed by the cell, consequently Arm protein levels are regulated by a multi-protein complex that targets Arm for degradation. My research has focused on identifying the mechanism(s) utilized by this destruction complex to regulate Arm degradation. Understanding how Arm degradation is regulated in the cell will give us a better understanding of the genesis of cancer in mammals, and may provide a therapeutic means to combat cancer.

Meagan Scott

Research Advisor:  Dr. Karin S. Pfennig

Previous studies have shown that female spadefoot toads, Spea bombifrons, change their mate choice preferences for conspecifics versus heterospecifics depending on an environmental cue (water level) that predicts whether females can benefit by hybridizing.  In high water where hybridization is not beneficial, females preferentially choose heterospecifics, whereas in low water females as a group are random in their preferences for conspecifics.  I hypothesized that individual condition of S. bombifrons females may determine whether they switch their preference for conspecifics versus heterospecifics.  I predicted that females in poor condition would be more likely to switch because they can benefit most by hybridizing.  I evaluated female mate preferences, female condition, and offspring growth of females that did and did not switch their behavior to test this prediction.  My results suggest how mating behaviors may play a critical role in maintaining hybrid zones between species.

Effective implementation of HBOC-201 in severe hemorrhagic shock resuscitation

Charles G. Sproule IV
Research Advisor:  James E. Manning, M.D.
The Carolina Resuscitation Research Group

Departmental Sponsor:  Dr. Frank Conlon

Blunt abdominal trauma accounts for a large portion of traumatic injuries, which are the leading cause of death among individuals age 15 to 40.  Blunt abdominal trauma can induce tissue injury, hemorrhagic shock and multi-system organ failure.  Ideal treatment of this condition includes restoration of intravascular volume and surgical repair of injuries.  Victims with severe hemorrhagic shock are currently given crystalloid fluid resuscitation until hospital arrival and availability of blood transfusion. This study is aimed at evaluating the potential value of an alternative therapy using a hemoglobin based oxygen carrier (HBOC-201).  HBOC-201 sustains survival and protects against multi-system organ failure compared to current therapies, and is stable at room temperature, making it a viable resource for pre-hospital emergency medical providers.  The most effective way to administer HBOC-201 has not been determined.  Using a swine model of blunt abdominal injury and severe hemorrhagic shock, fluid resuscitation with a standard colloid solution (Hetastarch) was compared with two different protocols of fluid resuscitation using HBOC-201.  Results of the study will provide insight on how to implement HBOC-201 most effectively as a bridging therapy to maintain survival until availability of definitive care.

Analysis of DNA Repair in Okra-mutant Drosophila

Rob van der Vaart

Research Advisor:  Dr. Jeff Sekelsky

I am working on DNA repair mechanisms in the fruit fly Drosophila melanogaster.  I have been testing certain mutant flies for their ability to undergo specific repair mechanisms in order to determine if the wild-type proteins are involved in these mechanisms.  Currently, I am focusing on a protein known as okra, which is related to several proteins involved in repair, and is itself believed to have some role in these pathways.

Role of Rab11 in the Regulation of Epithelial Integrity and Cell Adhesion

Daniel Willner

Research Advisor:  Dr. Mark Peifer

My research focuses on the role of the protein Rab11 in the regulation of epithelial integrity and cell adhesion during development of a Drosophila melanogaster embryo. The ability of epithelial cells to adhere to each other and to develop properly is controlled, in part, by the Adherens Junction (AJ), a protein complex found on the apico-lateral portion of the cells. We hypothesized that the endocytosis and exocytosis of DE-Cadherin, one protein component of the AJ, regulates the strength of cell adhesion. Additionally, we hypothesized that Rab11 plays a role in the recycling and exocytosis of DE-Cadherin to the plasma membrane. To test these hypotheses, we performed experiments using the loss of function alleles of rab11 to determine the effects that decreased levels of Rab11 have on proper epithelial development. These mutants exhibit cuticle defects, decreased levels of DE-Cadherin, improperly developed epithelial tissue and fragmented AJs.

Biosynthesis of a Novel Antibiotic – Agrocin 84

Alexandra Wright

Research Advisor:  Dr. John Reader

Departmental Sponsor:  Dr. Victoria Bautch

Agrobacterium tumefaciens causes Crown Gall disease in plants and is responsible for severe economic losses from crops worldwide.  The disease has been successfully prevented using the bacterial biocontrol agent Agrobacterium radiobacter, which produces a unique antibiotic - agrocin 84.  Known as the “Trojan horse” toxin, agrocin 84 mimics a bacterial food source and kills the pathogen once inside by preventing the production of its proteins.  Current research seeks to determine how agrocin 84 is produced and how it causes its inhibitory effects.  Focusing on the hypothesized initial stages of agrocin 84’s biochemistry pathway, I am attempting to discover the biochemical role of each of three enzymes encoded by their respective genes - agnA, agnB1, and agnC5 - by performing a series of in vitro enzyme assays.  Understanding agrocin 84 biosynthesis will help prevent the threat of bacterial resistance and also potentially lead to the development of novel antibiotics against other infectious diseases.