Biochemistry, Biophysics, and Structural Biology Commons^™

Impact Of Conformational Change, Solvation Environment, And Post-Translational Modification On Desulfurization Enzyme 2'-Hydroxybiphenyl-2-Sulfinate Desulfinase (Dszb) Stability And Activity, Landon C. Mills

Theses and Dissertations--Chemical and Materials Engineering

Naturally occurring enzymatic pathways enable highly specific, rapid thiophenic sulfur cleavage occurring at ambient temperature and pressure, which may be harnessed for the desulfurization of petroleum-based fuel. One pathway found in bacteria is a four-step catabolic pathway (the 4S pathway) converting dibenzothiophene (DBT), a common crude oil contaminant, into 2-hydroxybiphenyl (HBP) without disrupting the carbon-carbon bonds. 2’-Hydroxybiphenyl-2-sulfinate desulfinase (DszB), the rate-limiting enzyme in the enzyme cascade, is capable of selectively cleaving carbon-sulfur bonds. Accordingly, understanding the molecular mechanisms of DszB activity may enable development of the cascade as industrial biotechnology. Based on crystallographic evidence, we hypothesized that DszB …

Illuminating Dna Packaging In Sperm Chromatin: How Polycation Lengths, Underprotamination And Disulfide Linkages Alters Dna Condensation And Stability, Daniel Kirchhoff

Theses and Dissertations--Chemistry

During spermiogenesis, somatic chromatin is remodeled and a vast majority (> 90%) of DNA histones are replaced by short arginine-rich peptides called protamines. This compaction is immense, with protamine-DNA self-assembly in sperm chromatin resulting in a final volume roughly 1/6th of a somatic nucleus. This near crystalline organization of the DNA in sperm is thought crucial both for the transport of the paternal genes as well as for the protection of genetic information as sperm chromatin is transcriptionally inactive and all DNA repair mechanisms are shut down.

Chapter 1 will include an overview of the topics discussed in this document, …

Multi-Scale Computational Studies Of Calcium (Ca2+) Signaling, Bin Sun

Theses and Dissertations--Chemistry

Ca²⁺ is an important messenger that affects almost all cellular processes. Ca²⁺ signaling involves events that happen at various time-scales such as Ca²⁺ diffusion, trans-membrane Ca²⁺ transport and Ca²⁺-mediated protein-protein interactions. In this work, we utilized multi-scale computational methods to quantitatively characterize Ca²⁺ diffusion efficiency, Ca²⁺ binding thermodynamics and molecular bases of Ca²⁺-dependent protein-protein interaction. Specifically, we studied 1) the electrokinetic transport of Ca²⁺ in confined sub-µm geometry with complicated surfacial properties. We characterized the effective diffusion constant of Ca²⁺ in a cell-like environment, which helps to understand …

Xylan Metabolism By Caulobacter Crescentus, Viet Bui

Masters Theses

Bacteria present unique opportunities to explore the molecular mechanisms of nutrient acquisition processes at single cell level under various experimental conditions. Caulobacter crescentus is a gram-negative oligotrophic environmental bacterium with adaptive physiological responses, such as slow growth or complete arrest of cell cycle, presence of sessile and motile progenies with the sessile cells growing stalk to enhance nutrient uptake for growth in low-nutrient conditions. Details of plant polysaccharide-derived carbon compound, such as cellobiose, maltose, and xylose utilization by C. crescentus can be found but molecular details or mechanisms of polysaccharide utilization, such as xylan, has not been reported. Database analyses …

Structural Characterization Of Black Widow Spider Dragline Silk Proteins Crp1 And Crp4, Mikayla Shanafelt

University of the Pacific Theses and Dissertations

Spider dragline silk is a biomaterial with outstanding material properties, possessing high-tensile strength and toughness. In nature, dragline silk serves a central role during spider locomotion and web construction. Today, scientists are racing to elucidate the molecular machinery governing silk extrusion, attempting to translate this knowledge into a mimicry process in the laboratory to create synthetic fibers for a wide range of different applications. During extrusion, it has been established that biochemical and mechanical forces govern spidroin folding, aggregation, and assembly. In black widow spiders, at least 7 different proteins have been identified as constituents of dragline silk fibers. These …

Evaluating Methods Of Obtaining Male Pheromone From Hymenochirus Sp. Using Analytical Chemistry, Vincent Wing-Kun Leung

University of the Pacific Theses and Dissertations

Male Hymenochirus sp. frogs are known to release pheromone that attracts females of the same species. Four methods for collecting secretions containing pheromone in Hymenochirus sp. were tested: norepinephrine injection, gonadotropin-releasing hormone injection, homogenization of gland tissue, and electrostimulation of the skin over the breeding gland area. The samples collected were analyzed using high-performance liquid chromatography (HPLC) and mass spectrometry. The HPLC chromatograph for the male norepinephrine sample contained a peak at 6.4 min that was not in the female norepinephrine sample HPLC chromatograph. The male norepinephrine sample mass spectrum had a peak of m/z 292.0 not in the female …

Assessing The Effects Of Antioxidants On Oxidative Stress In Triple-Negative Breast Cancer Cells Via Protein Carbonylation, Dalton Sheffield

Honors Theses

Breast cancer is a highly complex, heterogeneous disease, and potential effective treatment options are being continuously researched in order to provide a method of halting cancer growth and metastasis. One area in particular involves alleviating oxidative stress within cancer cells. Oxidative stress is generally defined as an imbalance between oxidant and antioxidant species in favor of the oxidants. Cancer cells use this oxidative stress to initiate carcinogenesis in cells through different mechanisms, and protein carbonylation is a primary biomarker used to quantify oxidative stress levels. Antioxidant compounds are those used to alleviate oxidative stress within cells. Here breast cancer cells …

Protein Templated Silver Nanoclusters, Greyson Keel

Honors Theses

Nanoclusters are smaller than their nanoparticle counterparts and have unique properties. Most research has been done on gold nanoclusters, but silver nanoclusters are said to be more robust. During the process of trying to create nanoclusters, several methods in the procedure were changed when gathering data: determining a successful silver concentration, working with the correct buffer, mixing gold and silver metals together, observing the effects of pH, and finding a good reducing agent. After experimenting with those changes, a successful protocol was adapted and modified from literature (Journal of Materials Chemistry, 2011, 21, 11205-11212) to produce the protein-templated Ag clusters. …

Structural Investigation Of Bcsc: Insight Into Periplasmic Transport During Cellulose Export, William Scott, Joel T. Weadge

Theses and Dissertations (Comprehensive)

A biofilm can be defined by a community of microbes coexisting within a self-produced protective polymeric matrix. Exopolysaccharide (EPS) is a key component in biofilms and a contributor to their virulence and pathogenicity. The cellulose bacterial synthesis complex is one such EPS system that is found in many Enterobacteriaceae,including Escherichia coli and Salmonella spp., and is responsible for the production and secretion of the EPS cellulose. BcsC is the periplasmic protein responsible for the export of the exopolysaccharide cellulose and was the focus of this research. Sequence homology comparisons and structural predictions between BcsC, and the previously characterized alginate …

Characterization Of The Red Complex Bacterial Biofilm, Alena Pratasouskaya

Theses and Dissertations (Comprehensive)

Commonly associated with severe inflammation and destruction of the tooth-supporting tissue is bacterial consortia Treponema denticola, Tannerella forsythia, and Porphyromonas gingivalis, collectively referred to as the red complex. The red complex uses the common bacterial strategy of producing and embedding itself in extracellular polymeric substance, which contributes to the recalcitrance of periodontitis and was therefore of interest in this study. The red complex static cultures were grown in combination with different chemicals in order to establish what changes accompany these chemical challenges. This research established that extracellular polymeric substance carbohydrate yields increased with time. Interestingly, carbohydrate composition …

Expression, Purification, Functional Characterization And Crystallization Of Three Porphyromonas Gingivalis Gene Products, Katarina Mandic

Theses and Dissertations (Comprehensive)

Dental biofilms are coupled polymicrobial aggregates that have attached to solid surfaces in the oral cavity. These collections of microorganisms are known to cause periodontal diseases that commence as localized inflammation of the gingiva and if untreated, eventually lead to irreversible alveolar bone resorption and tooth loss. Porphyromonas gingivalis is one of three periodontal pathogens that make up the “Red Complex”; a bacterial consortium responsible for the production of polysaccharide-rich biofilms that are essential to the inception and progression of periodontal disease. The dysbiosis and destructive inflammation caused by these organisms propel a self-sustained feed-forward loop that perpetuates periodontal disease. …

Screening Of Human Serum/Plasma Using Vibrational Spectroscopy For Early Disease Diagnostics And Therapeutic Drug Monitoring, Drishya Rajan Parachalil [Thesis]

Doctoral

Analysis of analytes present in the blood stream can potentially deliver crucial information on patient health and indicate the presence of numerous pathologies. Existing clinical techniques for this analysis can, however, be costly and time-consuming. The potential of Raman spectroscopic analysis of human plasma and/or serum for diagnostic purposes has been widely investigated and, increasingly, its feasibility for clinical translation has been explored. However, as the concentration of many analytes in plasma/serum is relatively low, to date such analysis has commonly been performed on air-dried drops deposited on substrates, leading to inhomogeneity and inconsistencies. This study explores the potential of …

Characterization Of The Effects Of Sex And Estrogen Receptor Signaling On Antigen-Specific T Cells For Immunotherapy, Flor Cecilia Navarro Negredo

Dissertations

Adoptive cell transfer (ACT) immunotherapy using antigen (Ag)-specific T cells is partially effective treating several malignancies but numerous challenges remain in order to improve its therapeutic potential. The roles of host factors, such as sex hormone receptor signaling, that can affect the T cell anti-tumor function remain understudied. The work performed in this dissertation characterized the role of estrogen signaling on T cell function in vitro, and during ACT immunotherapy against hepatocellular carcinoma (HCC) in vivo. Estrogen signaling through ERa enhanced the expression and secretion of Type I effector cytokines including IFNg, TNFa, and Granzyme B in male and female …

Yczr, A New Case Of Plp-Dependent Mocr/Gabr Type Transcription Regulator In Klebsiella Pneumonia, Yuanzhang Zheng

Dissertations

Increasing number of genes encoding PLP-dependent transcription regulators, MocR/GabR type regulators, have been identified in various bacterial genomes. However, only a handful of them, including MocR, PdxR and GabR have been studied experimentally. They control different aspects of the bacterial metabolism. Only GabR has reported crystallographic structures. MocR/GabR regulators possess a chimeric structure consisted of a WHTH DNA binding domain and an Aminotransferase-like regulation domain, which can bind PLP as an effector in transcription regulation. Such a chimeric construct presents an interesting case in molecular evolution. The regulation domains of All MocR/GabR type regulators loss their catalytic capacity during evolution …

Co-Expression Of Feedback Resistant Enzymes In Phenylalanine Biosynthesis Pathway To Increase Phenylalanine Production, Charintip Yenyuvadee

Chulalongkorn University Theses and Dissertations (Chula ETD)

L-Phenylalanine (L-Phe) is an important commercial amino acid. It is widely used in food and pharmaceutical industries. Currently, the requirement of L-Phe is increased according to the great demand for the low-calorie sweetener, aspartame. In Escherichia coli, the synthesis of L-Phe is controlled by the multi-hierarchical regulations. AroG isoform of 3-deoxy- D-arabino-heptulosonate-7-phosphate synthase (DAHP synthase) and chorismate mutase/prephenate dehydratase (PheA), two important enzymes, are feedback inhibited by LPhe. Co-expression of feedback-resistant pheA (pheA[superscript L359D]) with other pivotal genes in L-Phe biosynthesis pathway: aroB, aroL, phedh, tktA, aroG, pheA, yddG, and glpF in pRSFDuet-1 (pPTFBLYA[superscript L359D]) elevated L-Phe production of E. …

Functional Characterization Of Cytosolic Ddx41 Sensor In Mediating Antiviral Immune Response In Black Tiger Shrimp Penaeus Monodon, Suthinee Soponpong

Chulalongkorn University Theses and Dissertations (Chula ETD)

DEAD (Asp-Glu-Ala-Asp) box polypeptide 41 (DDX41), a receptor belonging to the DExD family, was recently identified as an intracellular DNA sensor in vertebrates. Here, we investigated the presence of cytosolic DNA sensing, DDX41 in shrimp Penaeus monodon. By searching for gene involved in DNA sensing cascade within the shrimp P. monodon EST database, 3 cDNA fragments exhibited similarity to DDX41 in various species were identified. Sequences assembly resulted in a complete ORF of Penaeus monodon DDX41 (PmDDX41) which has 1868-bp encoding a putative protein of 620 amino acid residues. The multiple sequence alignment of deduced amino acid sequence of PmDDX41 …

Fructooligosaccharide Synthesis By Immobilized Inulosucrase From Lactobacillus Reuteri 121 And Improvement Of Product Pattern Using Site-Directed Mutagenesis, Thanapon Charoenwongpaiboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Inulin-type fructooligosaccharides (IFOS) are well-known prebiotics which can be produced from sucrose using bacterial inulosucrase (E.C. 2.4.1.9). However, the use of inulosucrase for IFOS synthesis has some limitations because it also synthesizes some polysaccharides and exhibits lower stability than the fungal enzymes. To overcome these limitations, improvement of inulosucrase was made by using enzyme immobilization and enzyme engineering. First, inulosucrase from Lactobacillus reuteri 121 was immobilized on a novel, high capacity core-shell chitosan beads using glutaraldehyde as a cross-linker. The results showed that both immobilized and free inulosucrase had the same optimum pH (5.5), while the optimum temperature was shifted …

Development Of Paper-Based 3d Cell Culture Devices And Real-Time Biosensing Applications, Naricha Pupinyo

Chulalongkorn University Theses and Dissertations (Chula ETD)

Due to its micro fibrous pores, paper has gained traction in the use as a scaffold for 3D cell culture. To study melanoma mechanism, screening the amount of melanin production and invasion study are major keys for drug development. In this work, we developed paper-based devices for culturing melanoma cells. Through the development process, we obtained the optimal parameters, which were applied for 3 different projects; 1) Anti-melanogenic effect screening, 2) Impedance-based E-screen assay, and 3) A membrane insert for real-time invasion assay. As a result of melanin production from melanocytes, the cells can be easily observed after a few …

Effects And Mechanisms Of Caesalpinia Mimosoides Leaf Extract On Oxidative Stress Resistance And Anti-Aging Activity In Caenorhabditis Elegans And Neurite Outgrowth Activity In Neuro2a Cells, Panthakarn Rangsinth

Chulalongkorn University Theses and Dissertations (Chula ETD)

World’s population of older people is rising, dietary supplements promoting healthy lifespan are needed. Moreover, Alzheimer’s disease (AD), an age-related degenerative disease, becomes a public health problem in aging society. Recent reports using cell culture models of AD suggest that amyloid precursor protein (APP), a protein causally related to AD, plays an important role as an inhibitor of neurite outgrowth. Medicinal herbs with neurite outgrowth stimulatory effect may help to prevent and cure AD. Moreover, studies suggest that dietary supplements from plant sources act in preventive nutrition, since they provide antioxidant action against oxidative stress, promote healthspan and prolong lifespan. …

Development Of Cell-Penetrating Peptides Targeting Nuclear And Extra-Nuclear Signaling Pathways In Cancer Cells, Panthita Kaewjanthong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Growth factors and hormones often mediate their biological effects through series of protein-protein interaction between cytoplasmic signaling molecules or transcription factors. Interfering of these protein-protein interactions has been shown to reduce or inhibit biological and growth responses to various growth factors and hormones. We previously demonstrated that progesterone receptor (PR) contains a polyproline domain (PPD) which directly interact to Src homology 3 (SH3) domain-containing molecules and expression of PR-PPD inhibits EGFR-mediated NSCLC cell proliferation. In this study, we investigated that the introduction of PR-PPD by cell-penetrating peptide could inhibit EGF-induced NSCLC cell proliferation. PR-PPD was attached to a cancer-specific CPP, …

ผลการปกป้องของสารสกัดใบรางจืดจากการเหนี่ยวนำความเป็นพิษด้วยกลูตาเมตในเซลล์ประสาท Ht-22 ผ่านวิถีออโตฟาจี, วุฒิพงษ์ วงศ์ทิพย์

Chulalongkorn University Theses and Dissertations (Chula ETD)

หนึ่งในสาเหตุสำคัญของการเกิดโรคความเสื่อมของระบบประสาทนั้นเกิดได้จากภาวะเครียดออกซิเดชันภายในเซลล์ประสาท โดยพบว่าสารสื่อประสาทชนิดกลูตาเมตเมื่อมีระดับสูงผิดปกติสามารถเหนี่ยวนำให้เกิดอนุมูลอิสระและภาวะเครียดออกซิเดชันนำไปสู่การสูญเสียและการตายของเซลล์ประสาทได้ โดยเฉพาะการตายของเซลล์จากการเกิดกระบวนการออโตฟาจีมากเกินไป ซึ่งเป็นกระบวนการที่มีบทบาทสำคัญในการควบคุมการตายของเซลล์ผ่านวิถีอื่นๆ รางจืด (Thunbergia laurifolia) เป็นพืชสมุนไพรไทยมีสรรพคุณในการถอนพิษ ต้านการอักเสบ และ ต้านอนุมูลอิสระได้ดี จุดประสงค์ในการวิจัยครั้งนี้ คือ ศึกษาคุณสมบัติการต้านอนุมูลอิสระของสารสกัดหยาบจากใบรางจืด และการปกป้องการตายของเซลล์ประสาทผ่านวิถีออโตฟาจี จากการเหนี่ยวนำภาวะเครียดออกซิเดชันด้วยกลูตาเมตโดยทดสอบในเซลล์ประสาทส่วนฮิปโปแคมปัสของหนูชนิด HT-22 ใบรางจืดถูกนำมาสกัดด้วยเอทานอล จากผลการทดสอบพบว่าสารสกัดหยาบจากใบรางจืดมีความสามารถในการต้านอนุมูลอิสระ และมีปริมาณสารประกอบ ฟลาโวนอยด์และฟีนอลิกสูง โดยจากการวิเคราะห์ด้วยเครื่อง LC-MS และเปรียบเทียบผลที่ได้กับฐานข้อมูล METLIN-(CA, USA) พบสารออกฤทธิ์สำคัญที่ยังไม่มีรายงานในสารสกัดเอทานอลของใบรางจืด ได้แก่ Apigenin 7-O-glucoside และ 7-Hydroxycoumarin ยิ่งไปกว่านั้นสารสกัดหยาบจากใบรางจืดยังสามารถลดการตายของเซลล์ประสาทจากการเหนี่ยวนำความเป็นพิษด้วยกลูตาเมต โดยสามารถยับยั้งการเกิดอนุมูลอิสระภายในเซลล์ และเพิ่มการแสดงออกของยีนต้านอนุมูลอิสระที่ทำหน้าที่สำคัญในกระบวนการต้านอนุมูลอิสระในร่างกาย ได้แก่ superoxide dismutase 1 และ 2 (SOD1 and SOD2) catalase (CAT) และ glutathione peroxidase (GPx) ซึ่งสัมพันธ์กับการลดการเกิดกระบวนการออโตฟาจีภายในเซลล์และเพิ่มปริมาณ ไมโตคอนเดรียโปรตีน โดยพบว่าสารสกัดหยาบจากใบรางจืดสามารถลดอัตราส่วนการแสดงออกของโปรตีน LC3B-II/LC3B-I และเพิ่มการแสดงออกของไมโตคอนเดรียโปรตีน TOM20 เมื่อทำการตรวจหาตำแหน่งที่จำเพาะต่อการแสดงออกของโปรตีนในกระบวนการออโตฟาจี (LC3B) และไมโตคอนเดรียด้วยกล้องจุลทรรศน์ชนิดคอนโฟคอล พบว่า สารสกัดหยาบจากใบรางจืดสามารถลดการเกิด LC3-puncta ซึ่งเป็นลักษณะเด่นของการเกิดกระบวนการออโตฟาจี นอกจากนี้สารสกัดหยาบจากใบรางจืดยังลดการ colocalization ของ LC3B และไมโตคอนเดรีย จากผลการศึกษานี้เราพบสารออกฤทธิ์สำคัญใหม่ที่ยังไม่มีรายงานมาก่อนของใบรางจืด โดยสารออกฤทธิ์นี้มีความสามารถในการปกป้องเซลล์ประสาทชนิด HT-22 จากภาวะเครียดออกซิเดชันและเป็นปัจจัยสำคัญทำให้สารสกัดจากใบรางจืดมีความสามารถลดการตายของเซลล์ประสาทผ่านวิถีออโตฟาจีได้ ซึ่งอาจสามารถนำไปพัฒนาเป็นสมุนไพรทางเลือกหรือยาเพื่อใช้ในการป้องกันหรือรักษาการเกิดโรคความเสื่อมของระบบประสาทได้ในอนาคต

Knob-Socket Investigation Of Stability And Specificity In Alpha-Helical Secondary And Quaternary Packing Structure, Taylor Renee Rabara

University of the Pacific Theses and Dissertations

The novel knob-socket (KS) model provides a construct to interpret and analyze the direct contributions of amino acid residues to the stability in α-helical protein structures. Based on residue preferences derived from a set of protein structures, the KS construct characterizes intra- and inter-helical packing into regular patterns of simple motifs. The KS model was used in the de novo design of an α-helical homodimer, KSα1.1. Using site-directed mutagenesis, KSα1.1 point mutants were designed to selectively increase and decrease stability by relating KS propensities with changes to α-helical structure. This study suggests that the sockets from the KS Model can …

Functional Analysis Of Bacillus Anthracis Aspartate Transcarbamoylase And Dihydroorotase, Katelyn Leigh Schwager Silva

Wayne State University Theses

There are many enzymes required for efficient and proper pyrimidine biosynthesis. The two that are most important and were discussed in this thesis are aspartate transcarbamoylase (ATCase) and dihydroorotase (DHOase). Both play an important role in not only pyrimidine biosynthesis production, but also mechanistic regulation of de novo synthesis. Anthrax is an infection caused by Bacillus anthracis. Here we studied ATCase and DHOase in Bacillus Anthracis. In this thesis we understood the effects of the enzymes ATCase and DHOase on pyrimidine biosynthesis. Adequate inhibitors of these enzymes would result in cell death and could pose as a cure to infection …

Cyclophilin A As A Molecular Switch Regulating Prolactin Receptor Mediated Signaling, Mammary Tumorigenesis And Metastasis, Shawn Hakim

Theses and Dissertations

Prolactin (PRL) and its receptor (PRLr) have been implicated in the development and progression of human breast cancer. PRL activates its receptor and induces activation of proximal Janus kinase 2 (Jak2) for signal transduction. Here, we sought to determine the role of PRLr-associated peptidyl-prolyl isomerase, cyclophilin A (CypA), in modulating structure/function relationships of the PRLr. It was demonstrated that CypA mediated PRL-induced conformational change of the CFP- and -YFP tagged forms of the PRLr cytoplasmic-tail, whereas CypA inhibition by NIM811 (N-methyl-4-isoleucine cyclosporin) or knockdown blocked the conformational change of the PRLr assessed by Fluorescence Resonance Energy Transfer (FRET) signal or …

Electrostatic Networks And Mechanisms Of Δph-Dependent Gating In The Human Voltage-Gated Proton Channel Hv1, Ashley L. Bennett

Theses and Dissertations

The structure of the voltage-gated proton (H⁺) channel Hv1 is homologous to the voltage sensor domain (VSD) of tetrameric voltage-gated Na⁺, K⁺ and Ca²⁺ channels (VGCs), but lacks a pore domain and instead forms a homodimer. Similar to other VSD proteins, Hv1 is gated by changes in membrane potential (V), but unlike VGCs, voltage-dependent gating in Hv1 is modulated by changes in the transmembrane pH gradient (DpH = pH_o - pH_i). In Hv1, pH_o or pH_i changes shift the open probability (P_OPEN)-V relation by ~40 mV per …

Targeting Sphingosine Kinase 2 As A Treatment For Cholangiocarcinoma, Anthony D. Stillman

Theses and Dissertations

Cholangiocarcinoma (CCA) has a high mortality rate and its occurrence is rising. This increase prompts the need for improved CCA treatments. Studies have suggested that CCA is highly reliant on the sphingosine-1-phosphate-receptor-2 (S1PR2) and sphingosine kinase 2 (SphK2). Recently, a competitive SphK2 inhibitor, ABC294640, has been approved for clinical trial. ABC294640 has the potential to treat CCA, which is support by a phase I clinical study that was able to temporarily treat a patient suffering from metastasized CCA with ABC294640. To determine the viability of ABC294640 as a treatment for CCA, this study focused on determining the effects of ABC294640 …

Stat5b And Stat5 Tetramers Are Essential For Ige-Mediated Mast Cell Function, Kasalina N. Kiwanuka

Theses and Dissertations

Signal Transducers and Activators of Transcription (STATs) are latent transcription factors that mediate several cellular responses. This protein family consists of seven members, STAT1 – 6 including two closely related molecules, STAT5a and STAT5b, that show 96% amino acid sequence homology and are critical for lymphoid, myeloid and erythroid cell development and function. Activated STAT proteins dimerize and translocate to the nucleus, where they bind to high-affinity DNA motifs to modulate gene expression. We recently identified STAT5b as the critical regulator of IgE-mediated cytokine production in mast cells. STAT5b knockout (KO) cells show decreased sensitivity to IgE-mediated passive systemic anaphylaxis …

Near-Infrared Fluorescent Probes For Sensitive Determination Of Lysosomal & Mitochondrial Ph In Live Cells, Wafa Mazi

Dissertations, Master's Theses and Master's Reports

Varied intracellular pH levels are critical for various physiological processes such as enzymatic activity, cell proliferation and apoptosis, ion transport, and muscle contraction. Cellular compartments, like lysosomes, must retain an acidic environment (pH ~ 4.5) to activate hydrolytic enzymes necessary for the breakdown of large biomolecules. Another cellular organelle, the mitochondria, provides the cell with energy and must retain an alkalis environment (pH ~ 8.0) for proper function. Substantial lysosomal and mitochondrial pH deviation is associated with cellular dysfunction and disease. Therefore, the precise detection of lysosomal and mitochondrial pH is essential to provide a better understanding of cellular physiological …

Characterization Of The Microbial Phosphonate-Activating Pntc Enzymes, Kyle Rice

Theses and Dissertations (Comprehensive)

New strategies are urgently needed to combat infectious diseases in an era of rising antibiotic resistance. Furthermore, an emerging appreciation for the human microbiome’s role in maintaining health motivates discovery of species-specific antibiotics that minimally disrupt our native bacterial communities. Small molecule modifications to bacterial cell surfaces represent a potentially rich source of new targets for next generation antibiotics, as these molecules mediate virulence and evasion of the host immune response. Phosphocholine (PCho) is a rare cell surface modification that contributes to virulence, and modifications with phosphonates like 2-aminoethylphosphonate (AEP) are even more unusual and therefore provide opportunities for species- …

Investigating Potential Multi-Protein Complexes Involving Emx2, Nicole Enger

All Master's Theses

The neocortex of the mammalian brain is allocated into specialized areas during embryonic development. In mice, as well as humans, the neocortex develops four primary areas: somatosensory, auditory, visual, and motor. In the adult neocortex, the boundaries between these four areas are marked by differences in cellular architecture and gene expression patterns. However, these physical boundaries are not evident during embryonic development of this structure. Rather, the neocortex initially appears uniform across its expanse, with one exception: a handful of proteins that regulate neocortical arealization are generated in gradients across the expanse of the neocortex and control the size of …