Life Sciences Commons^™

The Replication Initiator Of The Cholera Pathogen’S Second Chromosome Shows Structural Similarity To Plasmid Initiators, Natalia Orlova, Matthew Gerding, Olha Ivashkiv, Paul Dominic B. Olinares, Brian T. Chait, Matthew K. Waldor, David Jeruzalmi

Publications and Research

The conserved DnaA-oriC system is used to initiate replication of primary chromosomes throughout the bacterial kingdom; however, bacteria with multipartite genomes evolved distinct systems to initiate replication of secondary chromosomes. In the cholera pathogen, Vibrio cholerae, and in related species, secondary chromosome replication requires the RctB initiator protein. Here, we show that RctB consists of four domains. The structure of its central two domains resembles that of several plasmid replication initiators. RctB contains at least three DNA binding winged-helix-turn-helix motifs, and mutations within any of these severely compromise biological activity. In the structure, RctB adopts a headto- head dimeric configuration …

Autophagy And Lipid Homeostasis In C. Elegans, Melissa J. Silvestrini

Dissertations, Theses, and Capstone Projects

The worldwide prevalence of obesity, particularly in developed nations, has become an epidemic in recent decades and the trend is continuing to rise. Moreover, the prevalence of obesity in children and adolescents is rising at an alarming rate. Obesity is associated with an increased risk of metabolic disorders including heart disease, insulin resistance, type 2 diabetes and nonalcoholic fatty liver disease. Therefore it is no surprise that lipid-related metabolic disorders have become a significant burden to our healthcare system. In recent years, the conserved cellular recycling process of autophagy has been linked to several lipid-related metabolic disorders, including insulin resistance, …

Molecular Analysis Of Ftsz-Ring Assembly In E. Coli Cytokinesis, Kuo-Hsiang Huang

Dissertations, Theses, and Capstone Projects

An essential first step in bacterial division is the assembly of a cytokinetic ring (Z-ring) formed by the tubulin-like FtsZ at midcell. The highly conserved core domain of FtsZ has been reported to mediate assembly of FtsZ polymers in vivo and in vitro. Species-specific differences in the FtsZ C-terminal domain such as the FtsZ CTV region and interactions with several modulatory proteins such as ZapC and ZapD, restricted to certain bacterial classes, also serve as key determinants of FtsZ protofilament bundling. Here, we characterize (i) the roles of the FtsZ CTV region in mediating both longitudinal and lateral interactions …

A Pretargeted Approach For The Multimodal Pet/Nirf Imaging Of Colorectal Cancer, Pierre Adumeau, Kathryn E. Carnazza, Christian Brand, Sean D. Carlin, Thomas Reiner, Brian J. Agnew, Jason S. Lewis, Brian M. Zeglis

Publications and Research

The complementary nature of positron emission tomography (PET) and near-infrared fluorescence (NIRF) imaging makes the development of strategies for the multimodal PET/NIRF imaging of cancer a very enticing prospect. Indeed, in the context of colorectal cancer, a single multimodal PET/NIRF imaging agent could be used to stage the disease, identify candidates for surgical intervention, and facilitate the image-guided resection of the disease. While antibodies have proven to be highly effective vectors for the delivery of radioisotopes and fluorophores to malignant tissues, the use of radioimmunoconjugates labeled with long-lived nuclides such as 89Zr poses two important clinical complications: high radiation doses …

Myelinating Glia Differentiation Is Regulated By Extracellular Matrix Elasticity, Mateusz M. Urbanski, Lyle Kingsbury, Daniel Moussouros, Imran Kassim, Saraf Mehjabeen, Navid Paknejad, Alicia Meléndez

Publications and Research

The mechanical properties of living tissues have a significant impact on cell differentiation, but remain unexplored in the context of myelin formation and repair. In the PNS, the extracellular matrix (ECM) incorporates a basal lamina significantly denser than the loosely organized CNS matrix. Inhibition of non-muscle myosin II (NMII) enhances central but impairs peripheral myelination and NMII has been implicated in cellular responses to changes in the elasticity of the ECM. To directly evaluate whether mechanotransduction plays a role in glial cell differentiation, we cultured Schwann cells (SC) and oligodendrocytes (OL) on matrices of variable elastic modulus, mimicking either their …

Receptor-Type Guanylyl Cyclase At 76c (Gyc76c) Regulates De Novo Lumen Formation During Drosophila Tracheal Development, Monn Monn Myat, Unisha Patel

Publications and Research

Lumen formation and maintenance are important for the development and function of essential organs such as the lung, kidney and vasculature. In the Drosophila embryonic trachea, lumena formde novo to connect the different tracheal branches into an interconnected network of tubes. Here, we identify a novel role for the receptor type guanylyl cyclase at 76C (Gyc76C) in de novo lumen formation in the Drosophila trachea.We show that in embryosmutant for gyc76C or its downsteam effector protein kinase G (PKG) 1, tracheal lumena are disconnected. Dorsal trunk (DT) cells of gyc76C mutant embryos migrate to contact each other and complete the …

Odorant Receptors Can Mediate Axonal Identity And Gene Choice Via Campindependent Mechanisms, Kiavash Movahedi, Xavier Grosmaitre, Paul Feinstein

Publications and Research

Odorant receptors (ORs) control several aspects of cell fate in olfactory sensory neurons (OSNs), including singular gene choice and axonal identity. The mechanisms of OR-induced axon guidance have been suggested to principally rely on G-protein signalling. Here, we report that for a subset of OSNs, deleting G proteins or altering their levels of signalling does not affect axonal identity. Signalling-deficient ORs or surrogate receptors that are unable to couple to Gs/Golf still provide axons with distinct identities and the anterior–posterior targeting of axons does not correlate with the levels of cAMP produced by genetic modifications. In addition, we refine the …

Tricurin, A Novel Formulation Of Curcumin, Epicatechin Gallate, And Resveratrol, Inhibits The Tumorigenicity Of Human Papillomaviruspositive Head And Neck Squamous Cell Carcinoma, Longzhu Piao, Sumit Mukherjee, Qing Chang, Xiujie Xie, Hong Li, Mario R. Castellanos, Probal Banerjee, Hassan Iqbal, Ryan Ivancic, Xueqian Wang, Theodoros N. Teknos, Quintin Pan

Publications and Research

Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent cancer worldwide with about 600,000 new cases diagnosed in the last year. The incidence of human papillomavirus-positive head and neck squamous cell carcinoma (HPV-positive HNSCC) has rapidly increased over the past 30 years prompting the suggestion that an epidemic may be on the horizon. Therefore, there is a clinical need to develop alternate therapeutic strategies to manage the growing number of HPV-positive HNSCC patients. TriCurin is a composition of three food-derived polyphenols in unique stoichiometric proportions consisting of curcumin from the spice turmeric, resveratrol from red grapes, and …

Dynamic Surfaces For The Study Of Mesenchymal Stem Cell Growth Through Adhesion Regulation, Jemma N. Roberts, Jugal Kishore Sahoo, Laura E. Mcnamara, Karl V. Burgess, Jingli Yang, Enateri V. Alakpa, Hilary J. Anderson, Jake Hay, Lesley-Anne Turner, Stephen J. Yarwood, Mischa Zelzer, Richard O.C. Oreffo, Rein V. Ulijn, Matthew J. Dalby

Advanced Science Research Center

Out of their niche environment, adult stem cells, such as mesenchymal stem cells (MSCs), spontaneously differentiate. This makes both studying these important regenerative cells and growing large numbers of stem cells for clinical use challenging. Traditional cell culture techniques have fallen short of meeting this challenge, but materials science offers hope. In this study, we have used emerging rules of managing adhesion/ cytoskeletal balance to prolong MSC cultures by fabricating controllable nanoscale cell interfaces using immobilized peptides that may be enzymatically activated to change their function. The surfaces can be altered (activated) at will to tip adhesion/cytoskeletal balance and initiate …

Intronic Cleavage And Polyadenylation Regulates Gene Expression During Dna Damage Response Through U1 Snrna, Emral Devany, Ji Yeon Park, Michael R. Murphy, George Zakusilo, Jorge Baquero, Xiaokan Zhang, Mainul Hoque, Bin Tian, Frida E. Kleiman

Publications and Research

The DNA damage response involves coordinated control of gene expression and DNA repair. Using deep sequencing, we found widespread changes of alternative cleavage and polyadenylation site usage on ultraviolet-treatment in mammalian cells. Alternative cleavage and polyadenylation regulation in the 3ʹ untranslated region is substantial, leading to both shortening and lengthening of 3ʹ untranslated regions of genes. Interestingly, a strong activation of intronic alternative cleavage and polyadenylation sites is detected, resulting in widespread expression of truncated transcripts. Intronic alternative cleavage and polyadenylation events are biased to the 5ʹ end of genes and affect gene groups with important functions in DNA damage …

Study Of Alternative Functions Of The Mitochondrial Protein Bak, Ma Su Su Aung

Student Theses and Dissertations

Research in the past 15 years has established roles for the pro-apoptotic proteins Bax and Bak in release of death signaling molecules from mitochondria. The process involves relocation of cytoplasmic Bax into the mitochondrial outer membrane to form a giant pore, MAC. Another MAC component, Bak, is constitutively present in the outer membrane regardless of apoptotic stimulation. In this study we investigated the role of Bak in mitochondrial function outside the context of apoptosis. We examined the effects of Bak elimination on emission of reactive oxygen species from mitochondria. Our results indicate a disturbance of free-radical production both in cultured …

A Revisited Phylogeography Of Nautilus Pompilius, Lauren E. Vandepas, Frederick D. Dooley, Gregory J. Barord, Billie J. Swalla, Peter D. Ward

Publications and Research

The cephalopod genus Nautilus is considered a “living fossil” with a contested number of extant and extinct species, and a benthic lifestyle that limits movement of animals between isolated seamounts and landmasses in the Indo-Pacific. Nautiluses are fished for their shells, most heavily in the Philippines, and these fisheries have little monitoring or regulation. Here, we evaluate the hypothesis that multiple species of Nautilus (e.g., N. belauensis, N. repertus and N. stenomphalus) are in fact one species with a diverse phenotypic and geologic range. Using mitochondrial markers, we show that nautiluses from the Philippines, eastern Australia (Great Barrier Reef), Vanuatu, …

Innervation Of Gill Lateral Cells In The Bivalve Mollusc Crassostrea Virginica Affects Cellular Membrane Potential And Cilia Activity, Edward J. Catapane, Michael Nelson, Trevon Adams, Margaret A. Carroll

Publications and Research

Gill lateral cells of Crassostrea virginica are innervated by the branchial nerve, which contains serotonergic and dopaminergic fibers that regulate cilia beating rate. Terminal release of serotonin or dopamine results in an increase or decrease, respectively, of cilia beating rate in lateral gill cells. In this study we used the voltage sensitive fluorescent probe DiBAC4(3) to quantify changes in gill lateral cell membrane potential in response to electrical stimulation of the branchial nerve or to applications of serotonin and dopamine, and correlate these changes to cilia beating rates. Application of serotonin to gill lateral cells caused prolonged membrane depolarization, similar …

Spatial Engineering Of Osteochondral Tissue Constructs Through Microfluidically Directed Differentiation Of Mesenchymal Stem Cells, Stephen M. Goldman, Gilda A. Barabino

Publications and Research

The development of tissue engineered osteochondral units has been slowed by a number of technical hurdles associated with recapitulating their heterogeneous nature ex vivo. Subsequently, numerous approaches with respect to cell sourcing, scaffolding composition, and culture media formulation have been pursued, which have led to high variability in outcomes and ultimately the lack of a consensus bioprocessing strategy. As such, the objective of this study was to standardize the design process by focusing on differentially supporting formation of cartilaginous and bony matrix by a single cell source in a spatially controlled manner within a single material system. A cell-polymer solution …

Characterization And Recombinant Expression Of Terebrid Venom Peptide From Terebra Guttata, John Moon, Juliette Gorson, Mary Elizabeth Wright, Laurel Yee, Samer Khawaja, Hye Young Shin, Yasmine Karma, Rajeeva Lochan Musunri, Michelle Yun, Mandë Holford

Publications and Research

Venom peptides found in terebrid snails expand the toolbox of active compounds that can be applied to investigate cellular physiology and can be further developed as future therapeutics. However, unlike other predatory organisms, such as snakes, terebrids produce very small quantities of venom, making it difficult to obtain sufficient amounts for biochemical characterization. Here, we describe the first recombinant expression and characterization of terebrid peptide, teretoxin Tgu6.1, from Terebra guttata. Tgu6.1 is a novel forty-four amino acid teretoxin peptide with a VI/VII cysteine framework (C–C–CC–C–C) similar to O, M and I conotoxin superfamilies. A ligation-independent cloning strategy with an ompT …

Dengue-Induced Autophagy, Virus Replication And Protection From Cell Death Require Er Stress (Perk) Pathway Activation, E. Datan, S. G. Roy, G. Germain, N. Zali, J. E. Mclean, G. Golshan, S. Harbajan, R. A. Lockshin, Z. Zakeri

Publications and Research

Avirus that reproduces in a host without killing cells can easily establish a successful infection. Previously, we showed that dengue-2, a virus that threatens 40% of the world, induces autophagy, enabling dengue to reproduce in cells without triggering cell death. Autophagy further protects the virus-laden cells from further insults. In this study, we evaluate how it does so; we show that dengue upregulates host pathways that increase autophagy, namely endoplasmic reticulum (ER) stress and ataxia telangiectasiamutated (ATM) signaling followed by production of reactive oxygen species (ROS). Inhibition of ER stress or ATM signaling abrogates the dengueconferred protection against other cell …

Analysis Of Enzyme-Responsive Peptide Surfaces By Raman Spectroscopy, Jugal Kishore Sahoo, Narayana M.S. Sirimuthu, Anne Canning, Mischa Zelzer, Duncan Graham, Rein V. Ulijn

Advanced Science Research Center

We report on the use of Raman spectroscopy as a tool to characterize model peptide functionalised surfaces. By taking advantage of Raman reporters built into the peptide sequence, the enzymatic hydrolysis of these peptides could be determined.

Toward Repurposing Metformin As A Precision Anti-Cancer Therapy Using Structural Systems Pharmacology, Thomas Hart, Shihab Dider, Weiwei Han, Hua Xu, Zhongming Zhao, Lei Xie

Publications and Research

Metformin, a drug prescribed to treat type-2 diabetes, exhibits anti-cancer effects in a portion of patients, but the direct molecular and genetic interactions leading to this pleiotropic effect have not yet been fully explored. To repurpose metformin as a precision anti-cancer therapy, we have developed a novel structural systems pharmacology approach to elucidate metformin’s molecular basis and genetic biomarkers of action. We integrated structural proteome-scale drug target identification with network biology analysis by combining structural genomic, functional genomic, and interactomic data. Through searching the human structural proteome, we identified twenty putative metformin binding targets and their interaction models. We experimentally …

Chamber-Specific Patterns Of Epicardium Formation In Zebrafish, Sana Khan

Dissertations, Theses, and Capstone Projects

The outer cardiac layer, the epicardium, coordinates the final steps of vertebrate heart development. This cardiac tissue arises from cells in the proepicardial organ (PEO) that forms around the base of the inflow tract. Its general location is conserved across species despite morphological differences. Cellular mechanisms of migration differ across species. Three strategies of PEO migration are described: 1) The floating cyst model - PEO cells released into the pericardial cavity are directed by fluid movements to migrate onto the myocardium; 2) Villi transfer - cardiac contractions may mediate multicellular PEO villi contact to the myocardium; and 3) Tissue bridge-mediated …

Lim Protein Ajuba Participates In The Repression Of Atr-Mediated Dna Damage Response In Human Cells, Sampada Kalan

Dissertations, Theses, and Capstone Projects

LIM proteins constitute a superfamily characterized by the presence of specialized domains called LIM. LIM domain is a unique double-zinc finger motif found in a variety of proteins and is mainly involved in protein-protein interactions. Previous work has implicated that members of the Zyxin subfamily of LIM proteins, namely TRIP6 and LPP are involved in the repression of the DNA damage response (DDR) at telomeres. We further explore if another member from this family has an influence on DDR prevention in the cells. Here, we describe a novel role for Ajuba, a Zyxin family LIM protein, in repressing inappropriate activation …

Role Of Bec-1/Beclin 1 And Autophagy Genes In C.Elegans Germline Cell Proliferation, Kristina Ames

Dissertations, Theses, and Capstone Projects

Autophagy is an evolutionary conserved process involved in the cellular adaptation to stress and basal levels of autophagy are crucial for cellular metabolism and homeostasis. Cellular recycling by autophagy is characterized by the formation of distinctive double-membrane vesicles (autophagosomes) that engulf unnecessary cytoplasmic components, such as organelles and long-lived proteins. Failure to remove protein aggregates and/or damaged organelles, via autophagy, has been implicated in various medical conditions such as liver disease, neurodegenerative diseases and cancer. Autophagy may suppress or promote cellular proliferation in tumors, depending on the type and metabolic state of the cell, where autophagy is generally believed to …

Deciphering The Role Of Gfi1b Gene Target Rgs18 In Erythro-Megakaryocytic Lineage Divergence, Ananya Sengupta

Dissertations, Theses, and Capstone Projects

The molecular programs that govern the specification of erythroid and megakaryocytic lineages remain incompletely defined. Gene targeting experiments have shown the transcriptional repressor Gfi (Growth factor independence) 1b to be essential for the generation of both erythroid and megakaryocyte cells. Transcriptional repression of Gfi1b target genes is mediated mainly by the cofactors LSD (lysine demethylase) 1 and CoREST/Rcor1 (REST corepressor 1) or other Rcor factors. To understand the mechanism of Gfi1b action, its target genes were identified by chromatin immunoprecipitation (ChIP on Chip) screens. In this study we present the role of Rgs18 (Regulator of G protein signaling 18), a …

Characterization Of Induced Pluripotent Stem Cell Microvesicle Genesis, Morphology And Pluripotent Content, Jing Zhou, Shima Ghoroghi, Alberto Benito-Martin, Hao Wu, Uchenna John Unachukwu, Linda Saxe Einbond, Sara Guariglia, Hector Peinado, Stephen Redenti

Publications and Research

Microvesicles (MVs) are lipid bilayer-covered cell fragments that range in diameter from 30 nm–1uM and are released from all cell types. An increasing number of studies reveal that MVs contain microRNA, mRNA and protein that can be detected in the extracellular space. In this study, we characterized induced pluripotent stem cell (iPSC) MV genesis, content and fusion to retinal progenitor cells (RPCs) in vitro. Nanoparticle tracking revealed that iPSCs released approximately 2200 MVs cell/hour in the first 12 hrs with an average diameter of 122 nm. Electron and light microscopic analysis of iPSCs showed MV release via lipid bilayer budding. …

Characterization Of Fluorescent Proteins For Three- And Four-Color Live-Cell Imaging In S. Cerevisiae, Ryo Higuchi-Sanabria, Enrique J. Garcia, Delia Tomoiaga, Emilia L. Munteanu, Paul Feinstein, Liza A. Pon

Publications and Research

Saccharomyces cerevisiae are widely used for imaging fluorescently tagged protein fusions. Fluorescent proteins can easily be inserted into yeast genes at their chromosomal locus, by homologous recombination, for expression of tagged proteins at endogenous levels. This is especially useful for incorporation of multiple fluorescent protein fusions into a single strain, which can be challenging in organisms where genetic manipulation is more complex. However, the availability of optimal fluorescent protein combinations for 3-color imaging is limited. Here, we have characterized a combination of fluorescent proteins, mTFP1/mCitrine/ mCherry for multicolor live cell imaging in S. cerevisiae. This combination can be used with …

Killer-Cell Immunoglobulin-Like Receptor (Kir) Gene Profiles Modify Hiv Disease Course, Not Hiv Acquisition In South African Women, V. Naranbhai, D. De Assis Rosa, L. Werner, R. Moodley, H. Hong, A. Kharsany, K. Mlisana, S. Sibeko, N. Garrett, D. Chopera, William H. Carr, Q. Abdool Karim, A. V. S. Hill, S. S. Abdool Karim, M. Altfeld, C. M. Gray, T. Ndung’U

Publications and Research

Background: Killer-cell Immunoglobulin-like Receptors(KIR) interact with Human Leukocyte Antigen(HLA) to modify natural killer- and T-cell function. KIR are implicated in HIV acquisition by small studies that have not been widely replicated. A role for KIR in HIV disease progression is more widely replicated and supported by functional studies.

Methods: To assess the role of KIR and KIR ligands in HIV acquisition and disease course, we studied at-risk women in South Africa between 2004–2010. Logistic regression was used for nested case–control analysis of 154 women who acquired vs. 155 who did not acquire HIV, despite high exposure. Linear mixed-effects models were …

Human Anatomy And Physiology Preparatory Course: Part 1 Of 4 (Interactive), Carlos Liachovitzky

Open Educational Resources

The overall purpose of these preparatory course set of learning objectives is to help students familiarize with some terms and some basic concepts they will find later in the Human Anatomy and Physiology I course.

These 40+ learning objectives to prepare for Human Anatomy and Physiology can be downloaded and played in a desktop, or laptop (windows exe file).

The entire course has four parts:

• Part 1
• Part 2
• Part 3
• Part 4

Each learning objective is followed by a set of multiple choice question similar to those found later in a Human Anatomy and Physiology course.

The organization and …

Expression And Function Of A Putative Cox-Like Gene In D. Melanogaster, Michelle S. Batchu

Dissertations and Theses

Cyclooxygenases (COX) are the enzymes that catalyze the conversion of arachidonic acid into prostaglandins. In mammals, isoform COX-1 is constitutively expressed, whereas the isoform COX-2 gene expression is induced, primarily at sites of inflammation. While eicosanoids play a major role in inflammation in insects, their existence in fruit flies has not been reported. Recent computational analyses by Qi and Singh (2014) have identified putative COX-like enzymes in the fruit fly Drosophila melanogaster. Here we compare the expression patterns of these enzymes and the effects of their knockdown in immune cells of D. melanogaster third instar larvae. Because of high genetic …

Human Anatomy And Physiology Preparatory Course: Part 3 Of 4 (Interactive), Carlos Liachovitzky

Open Educational Resources

he overall purpose of these preparatory course set of learning objectives is to help students familiarize with some terms and some basic concepts they will find later in the Human Anatomy and Physiology I course.

These 40+ learning objectives to prepare for Human Anatomy and Physiology can be downloaded and played in a desktop, or laptop (windows exe file).

The entire course has four parts:

• Part 1
• Part 2
• Part 3
• Part 4

Each learning objective is followed by a set of multiple choice question similar to those found later in a Human Anatomy and Physiology course.

Human Anatomy And Physiology Preparatory Course: Part 2 Of 4 (Interactive), Carlos Liachovitzky

Open Educational Resources

The overall purpose of these preparatory course set of learning objectives is to help students familiarize with some terms and some basic concepts they will find later in the Human Anatomy and Physiology I course.

These 40+ learning objectives to prepare for Human Anatomy and Physiology can be downloaded and played in a desktop, or laptop (windows exe file).

The entire course has four parts:

• Part 1
• Part 2
• Part 3
• Part 4

Each learning objective is followed by a set of multiple choice question similar to those found later in a Human Anatomy and Physiology course.

Human Anatomy And Physiology Preparatory Course: Part 4 Of 4 (Interactive), Carlos Liachovitzky

Open Educational Resources

The overall purpose of these preparatory course set of learning objectives is to help students familiarize with some terms and some basic concepts they will find later in the Human Anatomy and Physiology I course.

These 40+ learning objectives to prepare for Human Anatomy and Physiology can be downloaded and played in a desktop, or laptop (windows exe file).

The entire course has four parts:

• Part 1
• Part 2
• Part 3
• Part 4

Each learning objective is followed by a set of multiple choice question similar to those found later in a Human Anatomy and Physiology course.