Biochemistry, Biophysics, and Structural Biology Commons^™

Epigenetic Effects Of Benzo(A)Pyrene In Fundulus Heteroclitus And Danio Rerio, Xiefan Fang

Electronic Theses and Dissertations

DNA methylation is one of the epigenetic mechanisms that controls gene expression and is vulnerable to early life environmental toxicant exposures. Our goal was to use two fish models, Fundulus heteroclitus and Danio rerio (zebrafish), to study the benzo(a)pyrene (BaP) effects on DNA methylation status and whether the alterations could contribute to BaP-mediated reproductive and developmental toxicities. Initially, we used Fundulus to study BaP effects on glycine N-methyltransferase (GNMT) expression throughout development. Fundulus embryos were exposed to waterborne BaP at nominally 10 or 100 μg/L and both GNMT mRNA expression and enzyme activity were measured. Quantitative PCR and whole mount …

Stable Expression Of Tuberculosis Vaccine Antigen In Lettuce Chloroplasts, Priya Saikumar Lakshmi

Electronic Theses and Dissertations

Tuberculosis (TB) is caused by Mycobacterium tuberculosis and is one of the leading reasons of death by an infectious bacterial pathogen. The development of TB vaccines has been recognized as a major public health priority by the World Health Organization. In this study, a potential candidate antigen, ESAT-6 (6 kDa early secretory antigenic target) was fused with cholera toxin B subunit (CTB). Transplastomic lettuce plants were generated expressing these fusion proteins. Site-specific transgene integration into the chloroplast genome was confirmed by polymerase chain reaction and Southern blot analysis. In transplastomic leaves, expression levels of fusion protein (CTB-ESAT6) varied depending upon …

Evolutionary Relationships Among Staphylococci And The Prevention Of Staphylococcus Aureus Nasal Colonization, Ryan Paul Lamers

Electronic Theses and Dissertations

Staphylococcus is a significant cause of human infection and mortality, worldwide. Currently, there are greater than 60 taxa within Staphylococcus, and nearly all are pathogenic. The collective potential for virulence among species of Staphylococcus heightens the overall clinical significance of this genus and argues for a thorough understanding of the evolutionary relationships among species. Within Staphylococcus, aureus is the most common cause of human infection, where nasal carriage of this bacterium is a known risk factor for autoinfection. The predisposition to infection by nasal carriers of S. aureus, and the ease with which strains are transferred between individuals, suggests that …

Synthesis, Characterization And Antibacterial Activity Of Silver Embedded Silica Nanoparticle/Nanogel Formulation, Roseline Menezes

Electronic Theses and Dissertations

The antibacterial property of silver (Ag) has been known since ancient time. It is reported in the literature that silver nanoparticles (AgNPs) exhibit improved antibacterial properties in comparison to silver ions of equivalent metallic Ag concentration. Such improvement in antibacterial activities is due to the high surface area to volume ratio of AgNPs (which facilitates interaction with the bacterial cells), increased release of silver ions and direct intra-cellular uptake of AgNPs leading to localized release of Ag ions. To date, over 300 consumer products containing AgNPs are available in the market and the inventory is rapidly expanding. The antibacterial efficacy …

Expression And Functional Evaluation Of Exendin 4 Fused To Cholera Toxin B Subunit In Tobacco Chloroplast To Treat Type 2 Diabetes, Ramya Nityanandam

Electronic Theses and Dissertations

The prevalence of type 2 diabetes has been steadily increasing around the globe. Glucagon like peptide (GLP-1), a powerful incretin increases insulin secretion in a glucose dependent manner. But GLP-1 is subjected to rapid enzymatic degradation (half-life: 2 min in circulation). The commercially available GLP-1 analog, exenatide has a longer half life with potent insulinotropic effects (about 2.4 hr) which requires cold storage and daily subcutaneous injections. In this study, exendin 4 (EX4), lizard derived GLP-1R agonist, was expressed as cholera toxin B subunit (CTB)-fusion protein in chloroplasts of tobacco to facilitate transmucosal delivery in the gut by utilizing the …

Expression Of Trichoderma Reesei Beta]-Mannanase In Tobacco Chloroplasts And Its Utilization In Lignocellulosic Woody Biomass Hydrolysis, Pankaj M. Agrawal

Electronic Theses and Dissertations

Lignocellulosic ethanol offers a promising alternative to conventional fossil fuels. One among the major limitations in the lignocellulosic biomass hydrolysis is unavailability of efficient and environmentally biomass degrading technologies. Plantbased production of these enzymes on large scale offers a cost effective solution. Cellulases, hemicellulases including mannanases and other accessory enzymes are required for conversion of lignocellulosic biomass into fermentable sugars. β- mannanase catalyzes endo-hydrolysis of the mannan backbone, a major constituent of woody biomass. In this study, man1 gene encoding β-mannanase was isolated from Trichoderma reesei and expressed via the chloroplast genome. PCR and Southern hybridization analysis confirmed the site-specific …

Short Peptides As Inhibitors Of Amyloid Aggregation, Bradley Neddenriep, Anastasia Calciano, Daniel Conti, Erin Sauve, Marissa Paterson, Edward Bruno, David A. Moffet

Chemistry and Biochemistry Faculty Works

The misfolding and aggregation of proteins into amyloid has been linked to a variety of age-related diseases. Aggregation of proteins, such as Aβ in Alzheimer's disease and Islet Amyloid Polypeptide (IAPP, amylin) in type 2 diabetes, appears to lead to the formation of toxic assemblies. These assemblies range in size from small oligomers (2-8 proteins) to large fibrils (thousands of proteins). It remains unclear how these amyloidogenic proteins misfold and form toxic species, but growing evidence suggests that inhibiting the aggregation of these proteins could slow, if not prevent altogether, the progression of these diseases. We describe the use of …

Quantifying Agonist Activity At G Protein-Coupled Receptors, Frederick J. Ehlert, Hinako Suga, Michael T. Griffin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

When an agonist activates a population of G protein-coupled receptors (GPCRs), it elicits a signaling pathway that culminates in the response of the cell or tissue. This process can be analyzed at the level of a single receptor, a population of receptors, or a downstream response. Here we describe how to analyze the downstream response to obtain an estimate of the agonist affinity constant for the active state of single receptors.

Receptors behave as quantal switches that alternate between active and inactive states (Figure 1). The active state interacts with specific G proteins or other signaling partners. In the absence …

Bio-Functionalized Clay Nanoparticles For Wound Healing Applications, Christopher Anthony Vaiana

Browse all Theses and Dissertations

Wound healing is a complex, multi-step process that can be summarized into three stages, namely hemostasis and inflammation, proliferation, and finally tissue remodeling. Battlefield wound healing demands rapid hemostasis using clotting or cauterizing agents to immediately limit blood loss, but this occurs at the expense of proper tissue repair beyond hemostasis. Layered silicate clays such as kaolin and montmorillonite (MMT) have been previously shown to induce blood clotting due to their ability to form charged interactions with clotting factors. The charge characteristics of sodium MMT (Na-MMT) also enable functionalization with active biomolecules. Herein we first functionalize three types of alumoinosilicate …

Interrogation Of The Distal Gut Microbiota Of Healthy Adolescents And Those With Irritable Bowel Syndrome, Laura J. Rigsbee

Browse all Theses and Dissertations

The human-associated microbiota has been the focus of much current research, with the microbiota inhabiting the gastrointestinal tract of particular interest. These organisms play many roles in human health and well-being. However, shifts in the composition of the intestinal microbiota have been associated with diseases such as irritable bowel syndrome, inflammatory bowel disease, and colon cancer. Several recent studies have reported on the distal gut microbiota composition of healthy adults and those with IBS, while there is a lack of studies devoted to adolescents. This study utilized a custom-designed Affymetrix Microbiota Array capable of detecting 775 phylo-species of intestinal bacteria …

Functional Metabolomics' Enhances Assessment Of Tissue Dysfunction As Demonstrated In A Rat Model Of Sub-Acute D-Serine Exposure, Isaie Sibomana

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We describe a methodology that combines urinary metabolomics with a tissue-specific stressor administration to enhance assessment of tissue function. Kidney function in rats was mildly compromised with a sub-acute dose of D-serine and stressed with furosemide. NMR-based metabolomics analyses showed no detectable effects due to D-serine alone; but furosemide or D-serine + furosemide groups, classified separately from each other, and from control. Furosemide alone caused a ca. 2-fold increase in glucose, lactate, choline, and a 30% decrease in TCA intermediates (p≤0.05). D-serine suppressed these effects and produced a 1.7-fold increase in a p-phenolic acid-derivative of tyrosine (PAdY) relative to control …

Novel Role Of Mecp2 In Developing Oligodendrocytes And Myelination, Daniel Moore

Theses and Dissertations

Methyl-CpG-binding protein 2 (MeCP2 is) is an epigenetic regulator that binds to methylated DNA. Initially identified as transcriptional repressor, MeCP2 also binds to different proteins functioning as gene activator. Importantly, MecCP2 gene mutations and changes in MeCP2 levels are associated to several forms of mental retardation and autism-related disorders; including Rett, a neurodevelopmental disorder affecting primarily girls. While brain MeCP2 was considered to be exclusively neuronal, this regulator is also present in glia. We found that oligodendrocytes, the myelinating cells of the central nervous system (CNS), express particularly high MeCP2 levels at a developmental stage that precedes their final maturation. …

Structural And Functional Alteration Of Full Length Pparα And Lxrα By Fatty Acids And Their Thioesters, Madhumitha Balanarasimha

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Peroxisome proliferator-activated receptors (PPAR) and liver X receptors (LXR) are known to play important roles in fatty acid metabolism, interact with each other, and function as heterodimeric partners. Although previous studies indicate that PPARα is activated by long chain fatty acyl-CoA thioesters (LCFA-CoA) and polyunsaturated fatty acids, little is known about the effects of these ligands on the function or interaction of PPARα and LXRα. In this study, hPPARα and hLXRα were shown to directly interact by circular dichroism, fluorescent binding assays, and co-immunoprecipitation. Further experiments suggested that although fatty acids resulted in small structural changes, they significantly altered binding …

The Role Of Mdm2 In Estrogen-Mediated Breast Cancer Cell Proliferation, Angelika Brekman

Dissertations, Theses, and Capstone Projects

Estrogen signaling is important in breast cancer development and progression. Mdm2, a negative regulator of the p53 tumor suppressor, is often over-expressed in estrogen receptor positive breast cancers. To study the role of Mdm2 in the estrogen-mediated breast cancer cell proliferation, we examined the effect of estrogen on the p53-Mdm2 pathway in estrogen receptor positive and p53 wild-type MCF-7 breast cancer cells. Estrogen-mediated increase in cell proliferation correlated with increased Mdm2, but no concomitant decrease in the p53 protein level. Blocking Mdm2 expression with inducible shRNA inhibited estrogen-mediated cell proliferation and colony formation in soft agar. Mdm2 knockdown in the …

Carbenoxolone Blocks The Light-Evoked Rise In Intracellular Calcium In Isolated Melanopsin Ganglion Cell Photoreceptors, Jayne R. Bramley, Erin M. Wiles, Patricia J. Sollars, Gary E. Pickard

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: Retinal ganglion cells expressing the photopigment melanopsin are intrinsically photosensitive (ipRGCs). These ganglion cell photoreceptors send axons to several central targets involved in a variety of functions. Within the retina ipRGCs provide excitatory drive to dopaminergic amacrine cells via glutamatergic signals and ipRGCs are coupled to widefield GABAergic amacrine cells via gap junctions. However, the extent to which ipRGCs are coupled to other retinal neurons in the ganglion cell layer via gap junctions is unclear. Carbenoxolone, a widely employed gap junction inhibitor, greatly reduces the number of retinal neurons exhibiting non-rod, non-cone mediated light-evoked Ca²⁺ signals suggesting extensive …

Y-Like Retinal Ganglion Cells Innervate The Dorsal Raphe Nucleus In The Mongolian Gerbil (Meriones Unguiculatus), Liju Luan, Chaoran Ren, Benson Wui-Man Lau, Jian Yang, Gary E. Pickard, Kwok-Fai So, Mingliang Pu

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: The dorsal raphe nucleus (DRN) of the mesencephalon is a complex multi-functional and multi-transmitter nucleus involved in a wide range of behavioral and physiological processes. The DRN receives a direct input from the retina. However little is known regarding the type of retinal ganglion cell (RGC) that innervates the DRN. We examined morphological characteristics and physiological properties of these DRN projecting ganglion cells.

Methodology/Principal Findings: The Mongolian gerbils are highly visual rodents with a diurnal/crepuscular activity rhythm. It has been widely used as experimental animals of various studies including seasonal affective disorders and depression. Young adult gerbils were used …

Challenges And Opportunities For Toxicology In Mexico, Rodrigo Franco, Balam Muñoz

School of Veterinary and Biomedical Sciences: Faculty Publications

We have developed this Special Issue titled “Challenges and Opportunities for Toxicology in Mexico” with the aim to highlight not only the challenges toxicology research faces in Mexico, but also the efforts and drive towards cutting edge research to address them. Altogether, this special issue should be a valuable source of information for all readers with an interest in toxicology and human health.

Mexico is an important economy worldwide and is a major exporter of several supplies and commodities. Because of this, its industry is a source of occupational exposure to several chemical derivatives (Nieusma 2011). The situation of occupational …

Intrinsically Photosensitive Retinal Ganglion Cells, Gary E. Pickard, Patricia J. Sollars

School of Veterinary and Biomedical Sciences: Faculty Publications

Intrinsically photosensitive retinal ganglion cells (ipRGCs) respond to light in the absence of all rod and cone photoreceptor input. The existence of these ganglion cell photoreceptors, although predicted from observations scattered over many decades, was not established until it was shown that a novel photopigment, melanopsin, was expressed in retinal ganglion cells of rodents and primates. Phototransduction in mammalian ipRGCs more closely resembles that of invertebrate than vertebrate photoreceptors and appears to be mediated by transient receptor potential channels. In the retina, ipRGCs provide excitatory drive to dopaminergic amacrine cells and ipRGCs are coupled to GABAergic amacrine cells via gap …

Long-Term Clinicopathological Characteristics Of Alpacas Naturally Infected With Bovine Viral Diarrhea Virus Type Ib, D. Bedenice, Edward J. Dubovi, Clayton Kelling, Jamie N Henningson, Christina L. Topliff, N. Parry

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: Substantial bovine viral diarrhea virus (BVDV)-related production losses in North American alpaca herds have been associated with BVDV type Ib infection.

Objectives: To classify and differentiate the long-term clinicopathological characteristics of BVDV type Ib infection of al- paca crias, after natural virus exposure. We hypothesized that persistently infected (PI) alpacas specifically demonstrate growth retardation, clinicopathological evidence of opportunistic infections, and early mortality.

Animals: Thirty-five crias naturally exposed to BVDV (18 acute, 3 chronic, 14 PIs), and 19 healthy cohort controls of 5 northeastern alpaca farms were prospectively evaluated over 2 years (September 2005–September 2008).

Methods: Observational cohort-control study.

Results: …

Gender Differences In Cns Autoimmunity Induced By Mimicry Epitope For Plp 139–151 In Sjl Mice, Chandirasegara Massilamany, Sivasubramani Thulasingam, David Steffen, Jay Reddy

Jay Reddy Publications

Development of multiple sclerosis (MS) is more prevalent in females than in males, but the underlying mechanisms are not clear. Microbial infections have been suspected as triggers of MS and it is not known whether gender differences in reactivity to environmental antigens contribute to the disease pathogenesis. We demonstrated that ACA 83–95, a mimicry epitope from Acanthamoeba castellanii for proteolipid protein (PLP) 139–151, induces clinical signs of encephalomyelitis in both male and female SJL mice. Conversely ACA 83–95-induced effector cells from males fail to induce disease in female mice. Although we found no gender differences in the frequencies of antigen-specific …