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Defining A Role For Inducible Heat Shock Protein 70 (Hsp70i) In Mediating Autoimmune Vitiligo, Jeffrey Alan Mosenson Jan 2013

Defining A Role For Inducible Heat Shock Protein 70 (Hsp70i) In Mediating Autoimmune Vitiligo, Jeffrey Alan Mosenson

Dissertations

Vitiligo is an autoimmune disease characterized by destruction of melanocytes, leaving 0.5% of the population with progressive depigmentation. Current treatments offer limited efficacy. Observations that heat shock proteins (HSPs) can serve as adjuvants in antitumor vaccines first suggested to us a link between HSPs and stress-induced vitiligo. Such proteins are marvelously well conserved throughout evolution, which has placed them in the spotlight for helping to understand the intriguing relationship between infection and immunity. Intracellularly, inducible heat shock protein 70 (HSP70i) is upregulated by stress and helps protect cells from undergoing apoptosis. In times of stress, melanocytes will secrete antigen ...


Behavior And Ecosystem Effects Of The Invasive Asian Clam (Corbicula Fluminea) In Urban Streams, Kayla Turek Jan 2013

Behavior And Ecosystem Effects Of The Invasive Asian Clam (Corbicula Fluminea) In Urban Streams, Kayla Turek

Master's Theses

Invasive species can be detrimental to freshwater ecosystems. By completing laboratory and field studies to observe processes and behaviors of the invasive Asian Clam (Corbicula fluminea), I documented pathways whereby this invasive species impacts aquatic ecosystems under conditions typical of urbanized streams I found. The predominant pathways by which clams impacted nitrogen (N) cycling was through excretion thus increasing ammonium (NH4+) flux out of sediment and through bioturbation, which increased nitrate (NO3-) diffusion to the sediment and dinitrogen gas (N2) production (i.e., denitrification). The effect was greater under urban conditions, where C. fluminea population density and water column NO3- ...


Targeting The Notch-1/Igf-1r/Akt Axis In At Orthotopic Model Of Advanced Non-Small Cell Lung Cancer, Shuang Liang Jan 2013

Targeting The Notch-1/Igf-1r/Akt Axis In At Orthotopic Model Of Advanced Non-Small Cell Lung Cancer, Shuang Liang

Dissertations

Lung cancer is the leading cause of cancer death in the U.S. and worldwide. The most frequent type of lung cancer is non-small cell lung cancer (NSCLC). NSCLC is mostly diagnosed at advanced stages (stage IIIB 18% of cases, stage IV 40% of cases) due to the lack of effective early detection methods. Thus, the discovery of alternative therapeutic strategies is of extreme importance.

Others and we have previously found that Notch signaling plays a crucial role in NSCLC. Our preliminary results indicate that Notch-1 provides necessary survival signals to NSCLC cells by positively regulating IGF-1R to activate the ...


Novel Role Of Erbb-2 In Inhibition Of Jagged-1-Mediated Trans-Activation Of Notch In Breast Cancer, Kinnari Pandya Jan 2013

Novel Role Of Erbb-2 In Inhibition Of Jagged-1-Mediated Trans-Activation Of Notch In Breast Cancer, Kinnari Pandya

Dissertations

The ErbB-2 gene is amplified and the resulting protein product overexpressed in 15-30% of breast tumors, and associated with aggressive behavior and poor overall survival. Currently, there are two FDA approved therapies targeting ErbB-2 for the treatment of ErbB-2 positive breast cancer: trastuzumab, a humanized monoclonal antibody is directed against the extracellular domain of ErbB-2 and lapatinib, a dual EGFR/ErbB-2 tyrosine kinase inhibitor. Unfortunately, anti-ErbB-2 therapy resistance remains a major problem in metastatic breast cancer. Our data suggested that gene amplification or overexpression of ErbB-2 inhibits Notch-1 transcriptional activity and trastuzumab or lapatinib increased

Notch-1 transcriptional activity. Furthermore, Notch-1 ...


Understanding The Posttranslational Regulation Of The Response Regulator Rcsb And Acetyl Phosphate As An Acetyl Group Donor In E. Coli, Linda Hu Jan 2013

Understanding The Posttranslational Regulation Of The Response Regulator Rcsb And Acetyl Phosphate As An Acetyl Group Donor In E. Coli, Linda Hu

Dissertations

The observation that Nepsilon-lysine acetylation occurs on a hundreds of proteins in bacteria is a recent discovery. To study the mechanisms that regulate acetylation and to determine if acetylation affects physiology, I studied the Escherichia coli response regulator and transcription factor RcsB, which was reported to be acetylated in vitro. To monitor RcsB activity, I measured transcription from the rprA promoter, which requires RcsB. I confirmed that RcsB is activated by phosphorylation through the Rcs phosphorelay and acetyl phosphate and showed that acetyl phosphate could phosphorylate RcsB. However, a mutant that accumulates acetyl phosphate (ackA) exhibited reduced rprA transcription instead ...


Ex Vivo Induction Of Human Regulatory T Cells, Kathleen Elizabeth Jaeger Jan 2013

Ex Vivo Induction Of Human Regulatory T Cells, Kathleen Elizabeth Jaeger

Dissertations

Regulatory T cells (Tregs) are indispensable in the human immune system in the maintenance of self-tolerance and immune homeostasis. The dysregulation of Treg number and/or function plays a critical role in the pathogenesis of cancer, allergy and human autoimmune pathologies such as multiple sclerosis, psoriasis, rheumatoid arthritis and diabetes. The primary aim of this research was to determine the molecular mechanisms and cellular interactions which promote human Treg induction. From umbilical cord blood (UCB) samples, we found that antigen receptor stimulation of UCB T cells via a CD14+ monocyte population leads to a predominant induction of Tregs.

Further studies ...


Biophysical Characterization Of Tryptophan Locales, Mg²+ Binding And Protein Folding In Gα Subunits, Matthew Najor Jan 2013

Biophysical Characterization Of Tryptophan Locales, Mg²+ Binding And Protein Folding In Gα Subunits, Matthew Najor

Dissertations

The objective of this study is to understand the structure of guanine nucleotide - binding (G) proteins using a variety of spectroscopic tools. G proteins are membrane-bound proteins consisting of α, β, and γ subunits required for the transduction of extracellular signals to various intracellular effectors. Activation of G protein coupled receptors by neurotransmitters or hormones result in a conformational change of a G protein that is triggered by the exchange of guanosine 5'- diphosphate (GDP) bound to the  subunit for guanosine 5'- triphosphate (GTP) and concomitant dissociation of the  dimer.

Wild type (WT) Giα1 has three tryptophan (W) residues. Intrinsic ...


The Role Of Linker 2 (L2) Region In Rhtrim5Α Assembly And Hiv-1 Restriction, Jayalaxmi Sastri Jan 2013

The Role Of Linker 2 (L2) Region In Rhtrim5Α Assembly And Hiv-1 Restriction, Jayalaxmi Sastri

Dissertations

The cellular restriction factor TRIM5alpha inhibits infection by numerous retroviruses in a species specific manner. TRIM5alpha protein from rhesus macaques (rhTRIM5alpha) and a related protein TRIM-Cyp from Owl monkeys restrict infection by HIV-1 while human TRIM5α (huTRIM5alpha) restricts infection by N-tropic murine leukemia virus (N-MLV) but not HIV-1. Several models have been proposed for retroviral restriction by TRIM5 proteins (TRIM5alpha and TRIMCyp). These models collectively suggest that TRIM5 proteins mediate restriction by recognizing specific determinants in the viral capsid and directly binding the capsid. Following binding, the TRIM5 proteins self-associate into large assemblies around the viral capsid, which leads to ...


Critical Functions Specified By The Mll Cxxc Domain Determine Leukemogenic Capacity, Noah Warren Birch Jan 2013

Critical Functions Specified By The Mll Cxxc Domain Determine Leukemogenic Capacity, Noah Warren Birch

Dissertations

TheMixed Lineage Leukemia(MLL) gene can participate in chromosomal translocations which generate a fusion protein leading to acute leukemia. A better understanding of how MLL fusion proteins contribute to leukemia is necessary in order to develop more effective treatments. In my dissertation project, I investigated the functional role of amino acids within the MLL CXXC domain to determine how specific residues contribute to leukemogenic capacity.

MLL fusion proteins retain the amino-terminal portion of MLL including the CXXC DNA-binding domain while the carboxy-terminal portion is comprised of a fusion partner. The closest homolog of MLL, MLL2 (alternatively named MLL4), also contains ...


Psychosocial Distress Mediates Immune Dysregulation Through Alterations In Global Epigenetic Patterns And Chromatin Remodeling Proteins, Karen Krukowski Jan 2013

Psychosocial Distress Mediates Immune Dysregulation Through Alterations In Global Epigenetic Patterns And Chromatin Remodeling Proteins, Karen Krukowski

Dissertations

Psychosocial distress, characterized by increased perceived stress, anxiety and mood disturbance, is a common response of women to a diagnosis of breast cancer (Northouse, 1992; Pettingale et al., 1988; Stark and House, 2000; Witek-Janusek et al., 2007). This psychosocial distress leads to activation of the hypothalamic-pituitary-adrenocortical (HPA) axis and increased circulating glucocorticoids (GCs) (Chrousos, 2000; Chrousos and Gold, 1992; Schoneveld and Cidlowski, 2007). Increased psychosocial distress and increased HPA activation can lead to immune dysregulation consisting of reduced natural killer (NK) cell activity (NKCA) (Biondi, 2001; Kiecolt-Glaser et al., 1987; Kiecolt-Glaser et al., 2002; Witek-Janusek et al., 2008; Witek-Janusek et ...


Characterization Of The Novel Response Regulator Sype: A Dual Regulator Of Biofilm Formation And Colonization In Vibrio Fischeri, Andrew Robert Morris Jan 2013

Characterization Of The Novel Response Regulator Sype: A Dual Regulator Of Biofilm Formation And Colonization In Vibrio Fischeri, Andrew Robert Morris

Dissertations

Biofilms, or surface-associated microbial communities encased in a matrix, represent a common mode of growth for many bacterial species. Importantly, biofilms often play significant roles in the association of bacteria with their animal hosts, including promoting attachment to and colonization of host tissues. The symbiosis between the bacterium Vibrio fischeri and its animal host Euprymna scolopes provides a natural model system for investigating the impact of biofilms on host infection. In particular, V. fischeri produces a specific biofilm to successfully initiate host colonization.

Biofilm formation by V. fischeri is a tightly regulated process involving a complex network of regulatory genes ...


Molecular Functions Of Mll Phd3 Binding To Its Ligands Cyp33 And H3k4me3, Gayathree Raman Jan 2013

Molecular Functions Of Mll Phd3 Binding To Its Ligands Cyp33 And H3k4me3, Gayathree Raman

Dissertations

Mixed Lineage Leukemia protein (MLL) is required for proper embryonic development, and hematopoiesis. It is a SET domain containing histone methyl transferase that trimethylates histone H3 on lysine 4 (H3K4Me3), a histone modification that correlates with active transcription. The 3rd PHD finger of MLL binds to H3K4me3. Thus MLL is a "writer" with an embedded "reader" for H3K4Me3. Cyp33 is another known ligand of MLL PHD3. Over expression of Cyp33 results in transcriptional repression of MLL target genes.

The aim of this study is to determine the biological function of MLL PHD3 binding to H3K4Me3 or Cyp33. Cyp33 binding to ...


Effects Of Acute Alcohol Exposure On Post Burn Intestinal Immunity: Role Of Il-23, Juan L. Rendon Jan 2013

Effects Of Acute Alcohol Exposure On Post Burn Intestinal Immunity: Role Of Il-23, Juan L. Rendon

Dissertations

More than one million burn injuries are reported yearly within the United States. These injuries result in approximately 500,000 emergency room visits and 40,000 hospitalizations annually. Greater than 50% of these injuries occur under the influence of alcohol/ethanol (EtOH) intoxication. Burn victims who sustain injury under the influence of EtOH exhibit significantly higher rates of morbidity and mortality than patients without EtOH exposure at the time of injury. Several lines of evidence suggest that gut pathogens and/or their products may play a role in the development of sepsis and multiple organ failure reported in burn and ...


Going Beyond Phosphorylation: Acetylphosphate-Mediated Ran Polymerase Acetylation And Caper Phosphorylation Co-Regulate Transcription Of Escherichia Coli Stress-Responsive Gene Cpxp, Bruno P. Lima Jan 2013

Going Beyond Phosphorylation: Acetylphosphate-Mediated Ran Polymerase Acetylation And Caper Phosphorylation Co-Regulate Transcription Of Escherichia Coli Stress-Responsive Gene Cpxp, Bruno P. Lima

Dissertations

The ability of bacteria to sense and adapt to environmental changes has al-lowed these organisms to thrive in all parts of the globe and to establish many complex interactions with the environments they live as well as other members of these environments. Crucial to monitoring extracellular conditions is a group of signaling pathways known as two-component signal transduction system (2CST). These systems relay information from the extracellular environment to the interior of the cell via a transfer of phosphoryl groups from the sensory protein know as sensor kinase (SK) to the output protein known as response regulator (RR).

In addition ...


A Study Of The Therapeutic Potential Of Af4 Mimetic Peptides, Nisha N. Barretto Jan 2013

A Study Of The Therapeutic Potential Of Af4 Mimetic Peptides, Nisha N. Barretto

Dissertations

Mixed lineage leukemias (MLL) are a group of acute and aggressive leukemias. They account for over 70% of infant leukemias, and 10% of acute adult leukemias. Pediatric ALL and therapy related MLL leukemias carry poor prognosis in spite of several advancement in the field of leukemia research. Therefore, new therapies for MLL leukemias are needed.

Majority of MLL leukemias arise due to the balanced translocations of the MLL gene. As a result of these translocations, chimeric MLL fusion proteins are expressed. The most frequently occurring MLL fusion proteins are known to aberrantly recruit the super elongation complex (SEC) resulting in ...


Characterization Of Chronic Glucocorticoid Exposure On Natural Killer Cell Function: A Model For Stress Induced Alterations On The Epigenetic Landscape, Justin Lee Eddy Jan 2013

Characterization Of Chronic Glucocorticoid Exposure On Natural Killer Cell Function: A Model For Stress Induced Alterations On The Epigenetic Landscape, Justin Lee Eddy

Dissertations

Psychological stress can impact immune function through altered glucocorticoid production. Natural killer (NK) cells and their effector functions are particularly susceptible to both psychological stress as well as exogenous glucocorticoids. The purpose of this study was to assess the impact of chronic glucocorticoid (GC) exposure on NK cells to investigate the immune dysregulation associated with periods of psychological stress.

Chronic in vitro treatment of the NK92 cell line produced a dichotomous NK phenotype with enhanced proinflammatory cytokine production yet reduced NK cell lytic activity (NKCA). This dichotomy was at the individual cell level where mRNA and protein levels for proinflammatory ...


Significance Of Protein Interactions In Mediating Af9 Function, Bhavna Malik Jan 2013

Significance Of Protein Interactions In Mediating Af9 Function, Bhavna Malik

Dissertations

Rearrangements of the MLL gene at chromosome band 11q23 have been associated with a heterogeneous group of lymphoid, myeloid and mixed lineage leukemias. MLL rearrangements occur approximately in 70% of infant leukemias and are also common in therapy-related leukemias where patients were previously treated with topoisomerase II inhibitors. Unfortunately, these patients have a poor prognosis. MLL gene rearrangements give rise to chimeric proteins that contain the N-terminal portion of MLL fused to the C-terminal portion of over 50 different fusion partners. The chimeric proteins cause constitutive expression of some MLL target genes such as HOXA9 and MEIS1, and enhanced proliferation ...


Particulates Initiate Immune Response Via Inducing Oxidative Stress-Mediated Nlrp3 Inflammasome Activation, Zhenyu Zhong Jan 2013

Particulates Initiate Immune Response Via Inducing Oxidative Stress-Mediated Nlrp3 Inflammasome Activation, Zhenyu Zhong

Dissertations

Liposomes are lipid particles formed by self-aggregated phospholipids. They are clinically used both as delivery vectors and immune adjuvants to treat many human infectious and cancerous diseases. However, how liposomes interact with host immune system remains poorly understood. Particularly, little is known about whether an innate immune receptor exists to sense liposomes. I hypothesize that liposomes activate NLRP3 inflammasome in macrophages, which results in the release of interleukin 1β (IL-1β), a proinflammatory cytokine that plays a key role in innate and adaptive immune responses.

To test my hypothesis, I determined the ability of inducing IL-1β secretion from macrophages by differentially ...


Effect Of Advanced Age On The Innate Immune Response To Cutaneous Wound Infection, Aleah Lin Brubaker Jan 2013

Effect Of Advanced Age On The Innate Immune Response To Cutaneous Wound Infection, Aleah Lin Brubaker

Dissertations

An estimated 25 billion in US health care expenditure is spent on care of chronic, non-healing wounds. The failure to effectively heal wounds is often compounded by co-morbidities, such as diabetes or obesity. Another major patient population afflicted with chronic wounds are the elderly. Advanced age is associated with a decline in immunologic function that contributes to a poor response to vaccination, infection and tissue injury resulting in prolonged hospital stays and age-related morbidity and mortality. Specifically, clinical observations and laboratory studies have suggested an age-related decline in cutaneous wound healing, marked by protracted wound closure, wound dehiscence and chronic ...


Evading Innate And Adaptive Immunity During Adenovirus Cell Entry, Shauna Marvin Jan 2013

Evading Innate And Adaptive Immunity During Adenovirus Cell Entry, Shauna Marvin

Dissertations

Adenovirus (Ad), a non-enveloped, dsDNA virus, enters cells via clathrin-mediated endocytosis. For viral genome delivery to the nucleus, Ad must penetrate endosomal membranes to create defects sufficient for the passage of the 90 nm diameter capsid across cell membranes. Recent observations suggest that adenovirus type 5 (Ad5) capsid uncoating occurs at the cell surface upon binding to both the coxsackievirus and adenovirus receptor and αv integrins. This uncoating event leads to the exposure of the capsid membrane lytic protein VI. Using the cytosolic protein galectin-3 (gal3) as a marker of membrane rupture, we demonstrate that Ad5 membrane rupture occurs ...


Evidence For Renewal And Reconstitution Of Marginal Zone Macrophages In Young And Aged Mice, Erika Bahamon Jan 2013

Evidence For Renewal And Reconstitution Of Marginal Zone Macrophages In Young And Aged Mice, Erika Bahamon

Master's Theses

Aging in humans and mice correlates with decline in immune health, affecting both innate and adaptive immunity. Response against blood-borne bacterial pathogens is compromised because of the deterioration of the marginal zones of the spleen and decrease in frequency of marginal zone macrophages (MZM). This thesis asked if low cell turnover is the cause for the decrease of MZM, using cell proliferation to indicate cell turnover in spleens of mice. First, evidence showed MZM proliferation occurred in spleens of young mice and was decreased in the MZM from aged mice. Second, transfer of young bone marrow into old mice replenished ...


The Effect Of Vitamin D On Human T Regulatory Cell Differentiation, Stephanie Anne Chapman Jan 2013

The Effect Of Vitamin D On Human T Regulatory Cell Differentiation, Stephanie Anne Chapman

Master's Theses

Regulatory T cells (Tregs) are required for the induction and maintenance of immune homeostasis. Singh et al. demonstrated that depletion of Tregs in mice results in a loss of self-tolerance that manifests in the development of autoimmune diseases such as Inflammatory Bowel Disease (IBD). In humans, autoimmune diseases such as IBD, Multiple Sclerosis (MS), and Type 1 Diabetes are thought to occur due to a deficiency in the number or function of Tregs. The importance of Tregs in modulating the human immune system is perhaps best exemplified by IPEX (immune dysregulation, polyendocrinopathy, enteropathy, x-linked syndrome), a severe autoimmune disease characterized ...


Aquatic Macroinvertebrate Response To Invasion And Subsequent Removal Of Typha × Glauca From Great Lakes Coastal Marshes, Kimberly Anne Greene Jan 2013

Aquatic Macroinvertebrate Response To Invasion And Subsequent Removal Of Typha × Glauca From Great Lakes Coastal Marshes, Kimberly Anne Greene

Master's Theses

Aquatic macroinvertebrates are important in wetland ecosystems; many fish and wildlife species depend upon them for food resources and they aid in nutrient cycling. Wetland macroinvertebrate communities are influenced by plant community composition; as such, this study examined two implications of invasive hybrid cattail, Typha × glauca (Typha), on aquatic macroinvertebrate communities in northern Great Lakes coastal wetlands: 1) how the presence of nearly monotypic stands of Typha alters wetland aquatic macroinvertebrate communities and 2) how manual removal of Typha, via mowing and manual tilling, impacts these invertebrate communities along with wetland plant communities. I found that in emergent marsh habitats ...


The Comparative Morphology Of The Pectoral Free Rays In Scorpaenoid Fishes (Perciformes: Scorpaenoidea)), Jeremy Peter Harris Jan 2013

The Comparative Morphology Of The Pectoral Free Rays In Scorpaenoid Fishes (Perciformes: Scorpaenoidea)), Jeremy Peter Harris

Master's Theses

The pectoral fins of many benthic taxa have evolved many unique features used to interact with the substrate. In one such group, the searobins (Triglidae: Scorpaenoidea), three of the pectoral fin rays have become separated from the fin as a whole, allowing them to operate as a separate appendage from the fin as a whole. The anatomical structure of these "free rays" was investigated and several previously unreported muscle and bone variations were found. This method was extended to include members of four other scorpaenoid families which possess free rays, which revealed important differences in the muscle, bone, and nervous ...


Characterization Of Inducible Regulatory T Cells: An Umbilical Cord Blood Model, Rebecca Anne Krier Jan 2013

Characterization Of Inducible Regulatory T Cells: An Umbilical Cord Blood Model, Rebecca Anne Krier

Master's Theses

The immune system is a group of structures and processes that protect us from disease. To function properly it must recognize a wide variety of pathogens such as viruses and bacteria. T cells play a crucial role in an immune response; however, an overactive immune response can lead to autoimmune diseases, therefore it is important that the immune system has the ability to negatively regulate an immune response. In the periphery, regulatory T cells (CD4+CD25+Foxp3+) are involved in the maintenance of self-tolerance and immune homeostasis. Mechanisms involved in the induction of iTregs from naïve CD4+ T cells include ...


Analysis Of The Minimal Promoter From The Hatching Enzyme A Gene, Anna Matejczyk Jan 2013

Analysis Of The Minimal Promoter From The Hatching Enzyme A Gene, Anna Matejczyk

Master's Theses

Hatching, defined as a biochemical or biophysical mechanism that allows the embryo to leave its protective envelope, is found in most animals. In fish, reptiles and amphibians, mostly oviparous animals, this means the emergence of the embryo from an egg. In mammals, viviparous animals, hatching is performed by the blastocyst in order to shed the zona pellucida.

Fish, an oviparous animal, takes advantage of a biochemical mechanism in order to hatch and emerge from their chorion, or egg envelope. The mechanism includes the use of hatching enzymes that are secreted in order to digest the envelope membrane. The genes controlling ...


Activity Patterns And Spatial Resource Selection Of The Eastern Garter Snake (Thamnophis Sirtalis Sirtalis), Matthew Gregory Most Jan 2013

Activity Patterns And Spatial Resource Selection Of The Eastern Garter Snake (Thamnophis Sirtalis Sirtalis), Matthew Gregory Most

Master's Theses

Snake species usually exhibit seasonal variations in activity patterns, home-range size and the use of respective habitat. Using mark-recapture protocols I marked 96 individual Thamnophis sirtalis sirtalis specimens in Lake Forest, IL to determine the independent variables that best explained habitat selection in a population of Eastern Garter Snakes (T. s. sirtalis). Specifically, I focused on the relationship between seasonal movement and home range size of male and female garter snakes. I analyzed the habitat preferences and spatial ecology of Eastern Garter Snakes during the 2011 sampling season and modeled the relationship between preferred or avoided habitat, in conjunction with ...


Exosomes: Antiviral Agents In The Human Lung, Jennifer Alexandra Novak Jan 2013

Exosomes: Antiviral Agents In The Human Lung, Jennifer Alexandra Novak

Master's Theses

Hundreds of interferon effectors comprise the immediate host response to virus infection. One family of interferon stimulated genes is the IFITM (Interferon-Induced Transmembrane) proteins. IFITM3, in particular, has been shown to block virus cell entry of Influenza A Virus, SARS Coronavirus, and West Nile Virus, among others. IFITM3 has also been identified as an essential factor for host protection against Influenza A Virus in mice and humans. However, the mechanism by which IFITM3 functions remains unclear.

IFITM3 may function both intracellularly and extracellularly to block virus infection in the human lung. The extracellular milieu contains microscopic vesicles termed exosomes which ...


Selective Expansion Of B Cells By Intestinal Microbiota, Karina Ochoa Jan 2013

Selective Expansion Of B Cells By Intestinal Microbiota, Karina Ochoa

Master's Theses

In rabbits, antibody diversity and B cell expansion are generated in gut-associated lymphoid tissues (GALT), in an antigen- and T cell-independent mechanism, and require interaction with intestinal microbiota. I investigated, in vitro, the mechanism by which commensals drive GALT reactions. Bacteria were isolated from the GALT of rabbits and identified by 16sRNA sequencing. I found that the commensals can bind to Ig, independently of their specificity. In addition, a ~20kDa bacterial molecule was immunoprecipitated with recombinant Ig molecules. Stimulation of B cells with selected bacterial molecules induced the activation of B cells. Stimulation of B cells through TLR2 induced the ...


Assessing The Effects Of Titanium Dioxide Nanoparticles On Microbial Communities In Stream Sediment Using Artificial Streams And High Throughput Screening, Alexandra Ozaki Jan 2013

Assessing The Effects Of Titanium Dioxide Nanoparticles On Microbial Communities In Stream Sediment Using Artificial Streams And High Throughput Screening, Alexandra Ozaki

Master's Theses

Nano-titanium dioxide (nano-TiO2) is an engineered nanomaterial used in a wide array of commercial products. The production and use of large amounts of nano-TiO2 is resulting in the unintended release to the environment. Nano-TiO2 is known to be cytotoxic due primarily to its ability to generate reactive oxygen species, and negative impacts on a variety of organisms have been demonstrated, but the effects of nano-TiO2 on complex microbial communities under ecologically relevant conditions have rarely been tested. We conducted a controlled manipulative experiment using recirculating model streams dosed with a one-time amendment of 1mg L-1 nano-TiO2 (specifically P25). Within one ...