Cell Biology Commons^™

The Lyme Disease Spirochete, Borrelia Burgdorferi, In Tick Species Collected From Raccoons (Procyon Lotor) And Opossums (Didelphis Virginiana) Trapped In The Warren And Barren Counties Of South Central Kentucky, Kristina Tackett

Masters Theses & Specialist Projects

The incidence of tick-borne zoonoses such as Ehrlichiosis, Rocky Mountain Spotted Fever, and Lyme disease has steadily increased in the southeastern United States in recent years. According to the Centers for Disease Control and Prevention (CDC), the southeastern states accounted for 1,200 of the 27,000 total cases of Lyme disease reported in the U.S. in 2007. Although Ixodes scapularis is the most commonly recognized vector for the Lyme disease spirochete Borrelia burgdorferi, Dermacentor variabilis (a common vector for Rocky Mountain Spotted Fever) also has been shown to be a viable host for this pathogen. The purpose of the present …

Cloning Of "Animal Cryptochrome" Cdna From The Model Organism Chlamydomonas Reinhardtii For Functional Analysis Of Its Protein Product, Shobha Lavanya Silparasetty

Masters Theses & Specialist Projects

reinhardtii, a unicellular green alga, is a model organism to study the circadian clock. Cryptochromes are the blue light photoreceptors that entrain the clock in some organisms. The CPH1 protein of C. reinhardtii resembles the cryptochromes of the plant model Arabidopsis, but whether CPH1 entrains the circadian clock in C. reinhardtii is not yet known. Recent reports have suggested the existence of one more cryptochrome in C. reinhardtii, which resembles the cryptochromes of animals. However, the amino acid sequence of this protein shows even higher sequence similarity with the 6-4 DNA photolyase of Arabidopsis. DNA photolyases …

Inhibition Of Pi 3-Kinase Signaling Contributes To Metronidazole Resistance In The Protozoan Parasite, Entamoeba Histolytica, Rhonda Powell

All Theses

Amoebiasis is defined as an intestinal infection with the human protozoan parasite, Entamoeba histolytica; approximately 100,000 deaths annually can be attributed to amoebiasis. Disease states range from asymptomatic colonization to invasive amoebiasis, characterized by abdominal pain and dysentery. Dissemination to extraintestinal sites, such as the liver and/or brain, can occur. Vesicle trafficking is critical for parasite virulence, and multiple signaling cascades within the pathogen facilitate these events.
One important regulator of signal transduction is the tightly controlled PI 3-kinase (PI3K), which phosphorylates the lipid, phosphatidylinositol bisphosphate (PIP₂), producing phosphatidylinositol trisphosphate (PIP₃). Effector proteins, such as Akt, …

Drosophila Adult Eye Model To Teach Scanning Electron Microscopy In An Undergraduate Cell Biology Laboratory, Meghana Tare, Oorvashi Roy Puli, Sarah M. Oros, Amit Singh

Biology Faculty Publications

We have devised an undergraduate laboratory exercise to study tissue morphology using fruit fly, Drosophila melanogaster, as the model organism. Drosophila can be reared in a cost effective manner in a short period of time. This experiment was a part of the undergraduate curriculum of the cell biology laboratory course aimed to demonstrate the use of scanning electron microscopy (SEM) technique to study the morphology of adult eye of Drosophila. The adult eye of Drosophila is a compound eye, which comprises of 800 unit eyes, and serves as an excellent model for SEM studies. We used flies that …

Identification Of A Conserved Cluster In The Rh Domain Of Grk Critical For Activation By Gpcrs, Faiza Baameur

Dissertations and Theses (Open Access)

One of the most critical aspects of G Protein Coupled Receptors (GPCRs) regulation is their rapid and acute desensitization following agonist stimulation. Phosphorylation of these receptors by GPCR kinases (GRK) is a major mechanism of desensitization. Considerable evidence from studies of rhodopsin kinase and GRK2 suggests there is an allosteric docking site for the receptor distinct from the GRK catalytic site. While the agonist-activated GPCR appears crucial for GRK activation, the molecular details of this interaction remain unclear. Recent studies suggested an important role for the N- and C-termini and domains in the small lobe of the kinase domain in …

The Role Of Multiple Ccaat-Binding Factors In Candida Albicans Gene Expression, Lashall Lynn Bates

Graduate Theses and Dissertations

The CCAAT-binding factor is a heterooligomeric transcription factor that is evolutionarily conserved in eukaryotes. In yeast, the DNA-binding component that interacts with the CCAAT consensus sequence in promoters consists of the subunits termed Hap2p, Hap3p and Hap5p. In yeast and fungi, a fourth subunit, Hap4p, is required for regulating gene expression. The goal of this research is to understand the function of the Candida albicans CCAAT-binding factor and how it relates to virulence and pathogenicity. C. albicans is a human opportunistic pathogen responsible for a variety of mucosal and systemic infections that result in significant morbidity and mortality, particularly in …

Characterization And Functional Regulation Of Bioactive Peptides In Avian Macrophages And Heterophils, Lakshmi Kannan

Graduate Theses and Dissertations

Oligopeptides and low molecular weight polypeptides play central roles as effectors and signal transducers acting as hormones, neurotransmitters, growth factors, toxins, and antimicrobial factors that are important for the survival of the organism. Owing to the ubiquitous involvement of peptides in many key regulatory processes, we have been interested to identify native peptides in different cells and tissues and understand their functions. To conduct our studies, we used avian macrophages and heterophils as models of specialized cells which constitute central components of innate immunity. These studies involved (a) qualitative identification and characterization of the peptides associated with high intensity mass …

Hexabromocyclododecane Decreases Tumor-Cell-Binding Capacity And Cell-Surface Protein Expression Of Human Natural Killer Cells, Natasha C. Hinkson, Margaret M. Whalen

Chemistry Faculty Research

Hexabromocyclododecane (HBCD) is a flame retardant that decreases the lytic function of human natural killer (NK) cells. NK cells defend against tumor cells and virally infected cells. Thus, HBCD has the potential to increase cancer incidence and viral infections. NK cells must bind to their targets for lysis to occur. Thus, concentrations of HBCD that decrease lytic function were examined for their ability to alter NK binding to tumor targets. Levels of HBCD that caused a loss of binding function were examined for effects on expression of cell surface proteins needed for binding. NK cells exposed to HBCD for 24 …

Phylogeography Of The Frog Leptodactylus Validus (Amphibia: Anura): Patterns And Timing Of Colonization Events In The Lesser Antilles, Arley Camargo, W. Ronald Heyer, Rafael O. De Sá

Biology Faculty Publications

The frog Leptodactylus validus occurs in northern South America, Trinidad and Tobago, and the southern Lesser Antilles (Grenada and St. Vincent). Mitochondrial DNA sequences were used to perform a nested clade phylogeographic analysis (NCPA), to date colonization events, and to analyze colonization patterns using on a relaxed molecular clock and coalescent simulations. L. validus originated on the mainland and first colonized Trinidad with subsequent independent colonizations of Tobago and the Lesser Antilles from Trinidad. The NCPA suggests a historical vicariant event between populations in Trinidad and Tobago from those in the Lesser Antilles. The colonization of Trinidad occurred 1 million …

Integral Membrane Proteins Brr6 And Apq12 Link Assembly Of The Nuclear Pore Complex To Lipid Homeostasis In The Endoplasmic Reticulum, Christine A. Hodge, Vineet Choudhary, Michael J. Wolyniak, John J. Scarcelli, Roger Schneiter, Charles N. Cole

Dartmouth Scholarship

Cells of Saccharomyces cerevisiae lacking Apq12, a nuclear envelope (NE)-endoplasmic reticulum (ER) integral membrane protein, are defective in assembly of nuclear pore complexes (NPCs), possibly because of defects in regulating membrane fluidity. We identified BRR6, which encodes an essential integral membrane protein of the NE-ER, as a dosage suppressor of apq12 Delta. Cells carrying the temperature-sensitive brr6-1 allele have been shown to have defects in nucleoporin localization, mRNA metabolism and nuclear transport. Electron microscopy revealed that brr6-1 cells have gross NE abnormalities and proliferation of the ER. brr6-1 cells were hypersensitive to compounds that affect membrane biophysical properties and to …

Tetrabromobisphenol A Has Immunosuppressive Effects On Human Natural Killer Cells, Esther Caroline Kibakaya, Krishna Stephen, Margaret M. Whalen

Chemistry Faculty Research

Human natural killer (NK) cells are lymphocytes that destroy tumor cells, virally-infected cells, and antibody-coated cells. Tetrabromobisphenol A (TBBPA) is used both as a reactive and as an additive flame retardant in a variety of materials and appears to contaminate the environment. TBBPA has been found in human blood samples and if it interferes with NK cell function, this could increase the risk of tumor development and/or viral infection. The present study examines the effects of exposure to various concentrations of TBBPA for 24 hr, 48 hr, and 6 days on the lytic function, tumor-target-binding function, and ATP levels of …

The Role Of Human Endogenous Retroviruses In Renal Cell Carcinoma, Michele D. Tisdale

Biological Sciences Theses & Dissertations

Human endogenous retroviruses make up approximately 8-9% of the human genome. A number of expressed HERVs, those that are actively transcribing, have been associated with various cancers. Suppression mechanisms that control HERV expression often fail or become more permissive in tissues where expression should be restricted. Previous studies have identified HERV expression in breast cancer tissues, whereas normal tissue HERV expression remained suppressed. In addition, studies of DNA hypermethylation have correlated with the ability to contribute to cancer development. Hypermethylation of several tumor suppressor genes occurs frequently in cancers and alterations in promoter regions could contribute to the development of …

Mtorc1 Hyperactivity Inhibits Serum Deprivation-Induced Apoptosis Via Increased Hexokinase Ii And Glut1 Expression, Sustained Mcl-1 Expression, And Glycogen Synthase Kinase 3Β Inhibition, Prashanth T. Bhaskar, Veronique Nogueira, Krushna C. Patra, Sang-Min Jeon, Youngkyu Park, R. Brooks Robey, Nissim Hay

Dartmouth Scholarship

The current concept is that Tsc-deficient cells are sensitized to apoptosis due to the inhibition of Akt activity by the negative feedback mechanism induced by the hyperactive mTORC1. Unexpectedly, however, we found that Tsc1/2-deficient cells exhibit increased resistance to serum deprivation-induced apoptosis. mTORC1 hyperactivity contributes to the apoptotic resistance of serum-deprived Tsc1/2-deficient cells in part by increasing the growth factor-independent expression of hexokinase II (HKII) and GLUT1. mTORC1-mediated increase in hypoxia-inducible factor 1α (HIF1α) abundance, which occurs in the absence of serum in normoxic Tsc2-deficient cells, contributes to these changes. Increased HIF1α abundance in these cells is attributed to both …

In Vivo Analysis Of The Notch Receptor S1 Cleavage, Robert J. Lake, Lisa M. Grimm, Alexey Veraksa, Spyros Artavanis-Tsakonas

Biology Faculty Publication Series

A ligand-independent cleavage (S1) in the extracellular domain of the mammalian Notch receptor results in what is considered to be the canonical heterodimeric form of Notch on the cell surface. The in vivo consequences and significance of this cleavage on Drosophila Notch signaling remain unclear and contradictory. We determined the cleavage site in Drosophila and examined its in vivo function by a transgenic analysis of receptors that cannot be cleaved. Our results demonstrate a correlation between loss of cleavage and loss of in vivo function of the Notch receptor, supporting the notion that S1 cleavage is an in vivo mechanism …

Stationary Phase Mutagenesis In Bacillus Subtilis: The Interaction Between Transcription And Error-Prone Replication In Conditions Of Stress, Mary Girard, Eduardo Robleto

Undergraduate Research Opportunities Program (UROP)

While under conditions of stress, non-dividing cells may acquire beneficial mutations. This is referred to as stationary phase mutagenesis, or adaptive mutagenesis. Previous research has shown that actively transcribed genes and those under selective pressure are prone to mutations that confer escape from non-dividing conditions. Accordingly, strains lacking transcription factors have shown a drastically lower number of mutations that confer escape while under amino acid starvation than those observed in the wildtype background. Also, error-prone DNA polymerases are known to be active in cells under stress and it has been shown that strains lacking an error-prone DNA polymerase display reduced …

Assessment Of The Endangered Species Podarcis Carbonelli On A Microgeographic Scale: A Molecular, Morphological And Physiological Approach, Maria Clara Figueirinhas Do Amaral

Masters Theses & Specialist Projects

The lizard Podarcis carbonelli is an endangered species endemic to the Iberian Peninsula. One location where this species occurs is at the Berlengas Natural Preserve, an Atlantic archipelago off the coast of Portugal. These island populations are geographically separated from nearby mainland populations. The fundamental question is, are these insular individuals distinct from the mainland populations? Four localities were chose for comparison: two island populations and two nearby coastal populations. We assessed this question using three distinct approaches: molecular, morphological and physiological approach. We sequenced the 12S RNA, the mtDNA Control Region and the 7th intron of the !-fibrinogen gene …

Searching For The Binding Partners For The Novel Phkg1 Variant Γ 181, Kishore Polireddy

Masters Theses & Specialist Projects

No abstract provided.

Adding Upstream Sequence And A Downstream Reporter To The Bile Acid Inducible Promoter Of Clostridium Scindens Vpi 12708, Bryan Patrick Mason

Masters Theses & Specialist Projects

Bile acids in the small intestines of animals serve to breakdown fats and fatsoluble vitamins. Most of the bile acids are reabsorbed into the enterohepatic circulation, but approximately five percent of these bile acids pass into the large intestine. These bile acids are swiftly deconjugated by the bacterial population, and then subjected to further intestinal bacterial chemical modifications. The most significant of these modifications are 7α-dehydroxylations which form secondary bile acids (deoxycholate and lithocholate). Much research has illuminated the 7α-dehydroxylation pathway: of particular interest is the bile acid inducible operon, for which Clostridium scindens VPI 12708 serves as the model …

Role Of Cd4+Cd25+ Regulatory T Lymphocytes In Experimental Toxoplasmosis, Sanjay Varikuti

Masters Theses & Specialist Projects

Toxoplasmosis is an important cause of congenital disease, and it is one of the most common opportunistic infections in patients with acquired immunodeficiency syndrome. The need for a reliable experimental model of this infection is crucial not only for achieving a better understanding of the patho-physiology of the disease, but also for developing better methods for evaluating new therapeutic regimens. The purpose of the present study was to investigate the role of CD4+CD25+ T regulatory lymphocytes in mice infected with Toxoplasma gondii. T regulatory (Treg) cells have been shown to play an important role in our immune system in …

Rapid Evolution Of Sex-Pheromone-Producing Enzyme In Drosophila, Troy R. Shirangi, Héloïse D. Dufour, Thomas M. Williams, Sean B. Carroll

Biology Faculty Publications

A wide range of organisms use sex pheromones to communicate with each other and to identify appropriate mating partners. While the evolution of chemical communication has been suggested to cause sexual isolation and speciation, the mechanisms that govern evolutionary transitions in sex pheromone production are poorly understood. Here, we decipher the molecular mechanisms underlying the rapid evolution in the expression of a gene involved in sex pheromone production in Drosophilid flies. Long-chain cuticular hydrocarbons (e.g., dienes) are produced female-specifically, notably via the activity of the desaturase DESAT-F, and are potent pheromones for male courtship behavior in Drosophila melanogaster. We …

The Effect Of Endothelin-1 On The Expression Of Cdk Inhibitors P21 & P27 In Bovine Corneal Endothelial Cells, Lakshmi Reddy Bollu

Masters Theses & Specialist Projects

Mammalian corneal endothelial cells are considered to be non-proliferative due to the arrest of cells at the G1 phase of the cell cycle. The purpose of this study was to determine whether the down regulation of cyclin dependant kinase inhibitors (p21cip1 and p27kip1) levels by Endothelin-1 (ET-1), would overcome the G1 phase arrest and promote cell cycle progression and proliferation in cultured BCECs (Bovine corneal endothelial cells). BCECs were isolated from bovine corneas and cultured in DMEM supplemented with 10% serum. 5-Bromo 2-deoxy Uridine (BrdU) incorporation was determined in serum starved cultures in 24-well plates as a measure of cell …

Hexabromocyclododecane Decreases The Lytic Function And Atp Levels Of Human Natural Killer Cells, Natasha C. Hinkson, Margaret M. Whalen

Chemistry Faculty Research

This study investigates the effect of hexabromocyclododecane (HBCD) on the lytic function of human natural killer (NK) cells and on ATP levels in NK cells. NK cells are capable of lysing tumor cells, virally infected cells, and antibody-coated cells. HBCD is a brominated cyclic alkane used primarily as an additive flame retardant. If HBCD interferes with NK cell function, this could increase risk of tumor development and/or viral infection. NK cells were exposed to various concentrations of HBCD for 24 and 48 h and 6 days before determining lytic function and ATP levels. ATP levels and lytic function were also …

Role Of Inn1 And Its Interactions With Hof1 And Cyk3 In Promoting Cleavage Furrow And Septum Formation In S. Cerevisiae, R. Nishihama, J. H. Schreiter, M. Onishi, Elizabeth A. Vallen, J. Hanna, K. Moravcevic, Margaret Flynn Lippincott , '01, Haesun Han , '08, M. A. Lemmon, J. R. Pringle, E. Bi

Biology Faculty Works

Cytokinesis requires coordination of actomyosin ring (AMR) contraction with rearrangements of the plasma membrane and extracellular matrix. In Saccharomyces cerevisiae, new membrane, the chitin synthase Chs2 (which forms the primary septum [PS]), and the protein Inn1 are all delivered to the division site upon mitotic exit even when the AMR is absent. Inn1 is essential for PS formation but not for Chs2 localization. The Inn1 C-terminal region is necessary for localization, and distinct PXXP motifs in this region mediate functionally important interactions with SH3 domains in the cytokinesis proteins Hof1 (an F-BAR protein) and Cyk3 (whose overexpression can restore PS …

Pivotal Role Of The A2a-Adrenoceptor In Producing Inflammation And Organ Injury In A Rat Model Of Sepsis, Michael Miksa, Padmalaya Des, Mian Zhou, Rongqian Wu, Weifeng Dong, Youxin Ji, Sanna M. Goyert, Thanjavur S. Ravikumar, Ping Wang

Publications and Research

Background: Norepinephrine (NE) modulates the responsiveness of macrophages to proinflammatory stimuli through the activation of adrenergic receptors (ARs). Being part of the stress response, early increases of NE in sepsis sustain adverse systemic inflammatory responses. The intestine is an important source of NE release in the early stage of cecal ligation and puncture (CLP)-induced sepsis in rats, which then stimulates TNF-a production in Kupffer cells (KCs) through the activation of the a2-AR. It is important to know which of the three a2-AR subtypes (i.e., a2A, a2B or a2C) is responsible for the upregulation of TNF-a production. The aim of this …

Effects Of Estrogen On Muscle Damage In Response To An Acute Resistance Exercise Protocol, Megan R. Wolf

Honors Scholar Theses

Creatine Kinase (CK) is used as a measure of exercise-induced muscle membrane damage. During acute eccentric (muscle lengthening) exercise, muscle sarcolemma, sarcoplasmic reticulum, and Z-lines are damaged, thus causing muscle proteins and enzymes to leak into the interstitial fluid.

Strenuous eccentric exercise produces an elevation of oxygen free radicals, which further increases muscle damage. Muscle soreness and fatigue can be attributed to this membrane damage. Estradiol, however, may preserve membrane stability post-exercise (Brancaccio, Maffulli, & Limongelli, 2007; Carter, Dobridge, & Hackney, 2001; Tiidus, 2001). Because estradiol has a similar structure to Vitamin E, which is known to have antioxidant properties, …

Analysis Of The Phosphorylated Forms Of Protein Kinase R, Christine Quartararo

Honors Scholar Theses

Protein Kinase R (PKR) is induced by interferon and activated by dsRNA. Subsequent autophosphorylation and phosphorylation of eIF2alpha inhibits viral replication. In the latent state PKR exists as an unphosphorylated monomer. Work in the Cole laboratory has shown two additional states, a phosphorylated monomeric state (pPKRm) and a phosphorylated dimeric state (pPKRd). RNA serves as a scaffold bringing two PKRs together allowing dimerization and autophosphorylation to occur. The contribution of each state to the function of PKR remains unclear. Western blots were performed to examine the phosphorylation states of the essential residues,

T446 and T451. Activity assays have shown activation …

Characterizing The Role Of Phaeobacter In The Mortality Of The Squid, Euprymna Scolopes, Brian Shawn Wong Won

Honors Scholar Theses

The subject of our study is the Hawaiian bobtail squid, Euprymna scolopes, which is known for its model symbiotic relationship with the bioluminescent bacterium, Vibrio fischeri. The interactions between E. scolopes and V. fischeri provide an exemplary model of the biochemical and molecular dynamics of symbiosis since both members can be cultivated separately and V. fischeri can be genetically modified 1. However, in a laboratory setting, the mortality of embryonic E. scolopes can be a recurrent problem. In many of these fatalities, the egg cases display a pink-hued biofilm, and rosy pigmentation has also been noted in the deaths of …

Optimization Of Protein Expression Of Four Transcription Factors Using Chaperone Proteins, Kaitlin Wilson

Honors Scholar Theses

Embryonic stem cells are unique in their ability to grow indefinitely while maintaining both pluripotency and self-renewal capabilities. These stem cells could be the answer to solving many of the debilitating and devastating diseases suffered by humans. Recently, the use of human derived embryonic stem cells has been effective in animal models in the treatment of spinal cord injuries (Kierstead et al., 2005).

Although the study of embryonic stem cells has become increasingly popular in the last decade, there is still much research to be done to increase the expression of valuable embryonic proteins which will induce pluripotency in the …

Characterization Of A Hypothetical Protein Critical For The Symbiotic Interaction Of Aeromonas Veronii And Hirudo Verbana, Kaitlin Vaughan

Honors Scholar Theses

The digestive tract symbiosis of the medicinal leech, Hirudo verbana, is a model system for studying the genes required for microbial colonization of digestive tracts, as H. verbana has only two species of bacteria that dominate the crop microbiota, Aeromonas veronii and a Rikenella-like bacterium. Signature-tagged mutagenesis (STM) of the A.

veronii strain, HM21R, revealed genes required for the colonization of the digestive tract. One of these mutants, JG573, has an interrupted gene that is predicted to encode a hypothetical protein. The region flanking the transposon insertion of this mutant was sequenced by primer walking.

Comparison of the flanking DNA …

Contribution Of The Novel C-Terminal Domain To The Ribosome Binding Activities Of Virulence Regulator Bipa, Heeren Makanji

Honors Scholar Theses

Bacterial GTPases regulate many cell functions, including the stress response, signal recognition, protein synthesis, and cell differentiation, through a molecular switch that is activated and deactivated depending on their nucleotide bound state (1). A member of the translational family of bacterial GTPases along with LepA and EF-G, BipA is a 67 kD protein that is essential for virulence and the stress response. Crystal structures from the Robinson lab have shown a unique C-terminal domain on BipA that has been implicated in ribosome binding. Using N-terminal deletion constructs, we have shown that the C-terminal domain is necessary, but not sufficient, to …