Cell Biology Commons^™

Age-Associated Methylation Suppresses Spry1, Leading To A Failure Of Re-Quiescence And Loss Of The Reserve Stem Cell Pool In Elderly Muscle., Anne Bigot, William J Duddy, Zamalou G Ouandaogo, Elisa Negroni, Virginie Mariot, Svetlana Ghimbovschi, Brennan Harmon, Aurore Wielgosik, Camille Loiseau, Joseph Devaney, Julie Dumonceaux, Gillian Butler-Browne, Vincent Mouly, Stéphanie Duguez

Genomics and Precision Medicine Faculty Publications

The molecular mechanisms by which aging affects stem cell number and function are poorly understood. Murine data have implicated cellular senescence in the loss of muscle stem cells with aging. Here, using human cells and by carrying out experiments within a strictly pre-senescent division count, we demonstrate an impaired capacity for stem cell self-renewal in elderly muscle. We link aging to an increased methylation of the SPRY1 gene, a known regulator of muscle stem cell quiescence. Replenishment of the reserve cell pool was modulated experimentally by demethylation or siRNA knockdown of SPRY1. We propose that suppression of SPRY1 by age-associated …

The Role Of Endothelin 3 In Melanoma Progression And Metastasis, Nikeisha L. Chin

FIU Electronic Theses and Dissertations

Endothelin receptor b (Ednrb) and its ligand Endothelin 3 (Edn3) have been implicated in melanoma. Several studies have shown an upregulation of EDNRB and EDN3 at both the protein and mRNA levels, as melanoma becomes more aggressive. This study investigated the putative role played by Edn3 over-expression in melanoma progression and angiogenesis in vivo. We crossed Tg(Grm1)Epv transgenic mice that aberrantly express metabotropic glutamate receptor1 under the Dopachrome tautomerase promoter, leading to spontaneous melanocytic lesions in the ears and tails that do not metastasize, with transgenics that overexpress Edn3 under the Keratin 5 promoter ( …

Stochastic Models For Plant Microtubule Self-Organization And Structure, Ezgi Can Eren, Ram Dixit, Natarajan Gautam

Biology Faculty Publications & Presentations

One of the key enablers of shape and growth in plant cells is the cortical microtubule (CMT) system, which is a polymer array that forms an appropriately-structured scaffolding in each cell. Plant biologists have shown that stochastic dynamics and simple rules of interactions between CMTs can lead to a coaligned CMT array structure. However, the mechanisms and conditions that cause CMT arrays to become organized are not well understood. It is prohibitively time-consuming to use actual plants to study the effect of various genetic mutations and environmental conditions on CMT self-organization. In fact, even computer simulations with multiple replications are …

Migration In The Social Stage Of Dictyostelium Discoideum Amoebae Impacts Competition, Chandra N. Jack, Neil J. Buttery, Boahemaa Adu-Oppong, Michael Powers, Christopher R.L. Thompson, David Queller, Joan E. Strassmann

Biology Faculty Publications & Presentations

Interaction conditions can change the balance of cooperation and conflict in multicellular groups. After aggregating together, cells of the social amoeba Dictyostelium discoideum may migrate as a group (known as a slug) to a new location. We consider this migration stage as an arena for social competition and conflict because the cells in the slug may not be from a genetically homogeneous population. In this study, we examined the interplay of two seemingly diametric actions, the solitary action of kin recognition and the collective action of slug migration in D. discoideum, to more fully understand the effects of social competition …

The Cababc Operon Essential For Biofilm And Rugose Colony Development In Vibrio Vulnificus, Jin Hwan Park, Youmi Jo, Song Yee Jang, Haenaem Kwon, Yasuhiko Irie, Matthew R. Parsek, Myung Hee Kim, Sang Ho Choi

Biology Faculty Publications

A transcriptome analysis identified Vibrio vulnificus cabABC genes which were preferentially expressed in biofilms. The cabABC genes were transcribed as a single operon. The cabA gene was induced by elevated 3′,5′-cyclic diguanylic acid (c-di-GMP) and encoded a calcium-binding protein CabA. Comparison of the biofilms produced by the cabA mutant and its parent strain JN111 in microtiter plates using crystal-violet staining demonstrated that CabA contributed to biofilm formation in a calcium-dependent manner under elevated c-di-GMP conditions. Genetic and biochemical analyses revealed that CabA was secreted to the cell exterior through functional CabB and CabC, distributed throughout the biofilm matrix, and produced …

Drosophila Eye Model To Study Neuroprotective Role Of Creb Binding Protein (Cbp) In Alzheimer’S Disease, Timothy Cutler, Ankita Sarkar, Michael Moran, Andrew Steffensmeier, Oorvashi Roy Puli, Greg Mancini, Meghana Tare

Biology Faculty Publications

Background: The progressive neurodegenerative disorder Alzheimer’s disease (AD) manifests as loss of cognitive functions, and finally leads to death of the affected individual. AD may result from accumulation of amyloid plaques. These amyloid plaques comprising of amyloid-beta 42 (Aβ42) polypeptides results from the improper cleavage of amyloid precursor protein (APP) in the brain. The Aβ42 plaques have been shown to disrupt the normal cellular processes and thereby trigger abnormal signaling which results in the death of neurons. However, the molecular-genetic mechanism(s) responsible for Aβ42 mediated neurodegeneration is yet to be fully understood.

Methodology/Principal Findings: We have utilized Gal4/UAS system to …

A Mitochondria-Anchored Isoform Of The Actin-Nucleating Spire Protein Regulates Mitochondrial Division, Uri Manor, Sadie Bartholomew, Gonen Golani, Eric Christenson, Michael Kozlov, Henry Higgs, James Spudich, Jennifer Lippincott-Schwartz

Dartmouth Scholarship

Mitochondrial division, essential for survival in mammals, is enhanced by an inter-organellar process involving ER tubules encircling and constricting mitochondria. The force for constriction is thought to involve actin polymerization by the ER-anchored isoform of the formin protein inverted formin 2 (INF2). Unknown is the mechanism triggering INF2-mediated actin polymerization at ER-mitochondria intersections. We show that a novel isoform of the formin-binding, actin-nucleating protein Spire, Spire1C, localizes to mitochondria and directly links mitochondria to the actin cytoskeleton and the ER. Spire1C binds INF2 and promotes actin assembly on mitochondrial surfaces. Disrupting either Spire1C actin- or formin-binding activities reduces mitochondrial constriction …

Characterization Of Putative Wnt3a-Inducible Enhancers, Katelynn C. Lee, Nicholas Hum, Aimy Sebastian, Gabriela Loots

STAR Program Research Presentations

The Wnt signaling pathway has been previously shown to play a major role in regulating bone metabolism and it is emerging as a target for the therapeutic intervention of bone thinning disorders such as osteoporosis. Several Wnt proteins have been shown to be expressed in bone and mutations in Wnt pathway members such as Wnt co-receptor Lrp5 and Wnt inhibitor Sost have been shown to be associated with low or high bone mass disorders, however, very little is known about specific roles played by different Wnt ligands in bone development, repair and remodeling. To identify downstream targets of Wnt signaling …

Beyond Bivariate Correlations: Three-Block Partial Least Squares Illustrated With Vegetation, Soil, And Topography, Daehyun Kim, Thomas J. Dewitt, César S. B. Costa, John A. Kupfer, Ryan W. Mcewan, J. Anthony Stallins

Biology Faculty Publications

Ecologists, particularly those engaged in biogeomorphic studies, often seek to connect data from three or more domains. Using three-block partial least squares regression, we present a procedure to quantify and define bi-variance and tri-variance of data blocks related to plant communities, their soil parameters, and topography. Bi-variance indicates the total amount of covariation between these three domains taken in pairs, whereas tri-variance refers to the common variance shared by all domains. We characterized relationships among three domains (plant communities, soil properties, topography) for a salt marsh, four coastal dunes, and two temperate forests spanning several regions in the world. We …

Polyq-Dependent Rna–Protein Assemblies Control Symmetry Breaking, Changhwan Lee, Patricia Occhipinti, Amy S. Gladfelter

Dartmouth Scholarship

Dendritic growth in fungi and neurons requires that multiple axes of polarity are established and maintained within the same cytoplasm. We have discovered that transcripts encoding key polarity factors including a formin, Bni1, and a polarisome scaffold, Spa2, are nonrandomly clustered in the cytosol to initiate and maintain sites of polarized growth in the fungus Ashbya gossypii. This asymmetric distribution requires the mRNAs to interact with a polyQ-containing protein, Whi3, and a Pumilio protein with a low-complexity sequence, Puf2. Cells lacking Whi3 or Puf2 had severe defects in establishing new sites of polarity and failed to localize Bni1 protein. Interaction …

The Role Of The Pleckstrin Homology Domain-Containing Protein Ckip-1 In Activation Of P21-Activated Kinase 1 (Pak1), Yong-Bae Kim, Yong Jae Shin, Adhiraj Roy, Jeong-Ho Kim

Biochemistry and Molecular Medicine Faculty Publications

Upon growth factor stimulation, PAK1 is recruited to the plasma membrane and activated by a mechanism that requires its phosphorylation at S223 by the protein kinase CK2. However, the upstream signaling molecules that regulate this phosphorylation event are not clearly defined. Here, we demonstrate a major role of the CK2α-interacting protein CKIP-1 in activation of PAK1. CK2α, CKIP-1 and PAK1 are translocated to membrane ruffles in response to the epidermal growth factor (EGF), where CKIP-1 mediates the interaction between CK2α, and PAK1 in a PI3K-dependent manner. Consistently, we observe that PAK1 mediates phosphorylation and modulation of the activity of p41-Arc, …

Genetic Changes To A Transcriptional Silencer Element Confers Phenotypic Diversity Within And Between Drosophila Species, Winslow C. Johnson, Alison J. Ordway, Masayoshi Watada, Jonathan N. Pruitt, Thomas M. Williams, Mark Rebeiz

Biology Faculty Publications

The modification of transcriptional regulation has become increasingly appreciated as a major contributor to morphological evolution. However, the role of negative-acting control elements (e.g. silencers) in generating morphological diversity has been generally overlooked relative to positive-acting “enhancer” elements. The highly variable body coloration patterns among Drosophilid insects represents a powerful model system in which the molecular alterations that underlie phenotypic diversity can be defined. In a survey of pigment phenotypes among geographically disparate Japanese populations of Drosophila auraria, we discovered a remarkable degree of variation in male-specific abdominal coloration. In testing the expression patterns of the major pigment-producing enzymes, …

Expressing And Characterizing Mechanosensitive Channels In Xenopus Oocytes, Grigory Maksaev, Elizabeth S. Haswell

Biology Faculty Publications & Presentations

The oocytes of the African clawed frog (Xenopus laevis) comprise one of the most widely used membrane protein expression systems. While frequently used for studies of transporters and ion channels, the application of this system to the study of mechanosensitive ion channels has been overlooked, perhaps due to a relative abundance of native expression systems. Recent advances, however, have illustrated the advantages of the oocyte system for studying plant and bacterial mechanosensitive channels. Here we describe in detail the methods used for heterologous expression and characterization of bacterial and plant mechanosensitive channels in Xenopus oocytes.

The Hippo Pathway Effector Yki Downregulates Wg Signaling To Promote Retinal Differentiation In The Drosophila Eye, Erika Lynn Wittkorn, Ankita Sarkar, Kristine Garcia, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

The evolutionarily conserved Hippo signaling pathway is known to regulate cell proliferation and maintain tissue homeostasis during development. We found that activation of Yorkie (Yki), the effector of the Hippo signaling pathway, causes separable effects on growth and differentiation of theDrosophila eye. We present evidence supporting a role for Yki in suppressing eye fate by downregulation of the core retinal determination genes. Other upstream regulators of the Hippo pathway mediate this effect of Yki on retinal differentiation. Here, we show that, in the developing eye, Yki can prevent retinal differentiation by blocking morphogenetic furrow (MF) progression and R8 specification. …

Evidence For Secretion Of A Netrin-1-Like Protein By Tetrahymena Thermophila, Victoria E. Ames, Grant Hooper, Aubrey J. Juris, Cole Knox, Jack Lightbody, Alexa C. Manthei, Jacob P. Olejarczyk, Benjamin D. Swenor, Amiah Warder, Emily B. Weindorf, Taylor L. Vander Plas, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

No abstract provided.

The Evolutionary Origination And Diversification Of A Dimorphic Gene Regulatory Network Through Parallel Innovations In Cis And Trans, Eric M. Camino, John C. Butts, Alison J. Ordway, Jordan E. Vellky, Mark Rebeiz, Thomas M. Williams

Biology Faculty Publications

The origination and diversification of morphological characteristics represents a key problem in understanding the evolution of development. Morphological traits result from gene regulatory networks (GRNs) that form a web of transcription factors, which regulate multiple cis-regulatory element (CRE) sequences to control the coordinated expression of differentiation genes. The formation and modification of GRNs must ultimately be understood at the level of individual regulatory linkages (i.e., transcription factor binding sites within CREs) that constitute the network. Here, we investigate how elements within a network originated and diversified to generate a broad range of abdominal pigmentation phenotypes among Sophophora fruit flies. …

Examining Phage Infection Utilizing Mycobacterium Smegmatis, Tanya L. Riddick

Undergraduate Research

Bacteriophages, also known as phages, are viruses that are ubiquitous and survive and replicate within the host of the bacterial cell, Mycobacterium smegmatis. They are considered one of the most abundant organisms on earth (10³¹). Structurally, they are 100-200nm in size and consist of a protein encapsulated head that contains DNA or RNA, a tail sheath and tail fibers. This research consisted of examining phage infection, by re-isolating a novel phage, Tango. Tango was originally isolated genetically in 2013 by a previous ISBT student, Anna Maccarrone. The phage was sent to genetic sequencing but two phages were discovered, …

Cell Type-Specific Responses To Wingless, Hedgehog And Decapentaplegic Are Essential For Patterning Early Eye-Antenna Disc In Drosophila, Jong-Hoon Won, Orkhon Tsogtbartarr, Wonseok Son, Amit Singh, Kwang-Wook Choi, Kyung-Ok Cho

Biology Faculty Publications

The Drosophila eye-antenna imaginal disc (ead) is a flattened sac of two-layered epithelia, from which most head structures are derived. Secreted morphogens like Wingless (Wg), Hedgehog (Hh), and Decapentaplegic (Dpp) are important for early patterning of ead, but the underlying mechanisms are still largely unknown. To understand how these morphogens function in the ead of early larval stages, we used wg-LacZ and dpp-Gal4 markers for the examination of wild-type and mutant eads. We found that the ead immediately after hatching was crescent-shaped with the Bolwig’s nerve at the ventral edge, suggesting that it consists of dorsal domain. In a subsequent …

Redox Regulation Of Ras Proteins In Dictyostelium Discoideum, Boris Castillo Chabeco

FIU Electronic Theses and Dissertations

Reactive oxygen species are a normal consequence of life in an aerobic environment. However when they deviate from the narrow permissible range in cells, oxidative damage can occur. Dictyostelium discoideum is a model organism ideal for the study of cell signaling events such as those affected by oxidative stress. It was previously shown that Ras signaling in Dictyostelium is affected by genetic inactivation of the antioxidant enzyme Superoxide dismutase C (SodC) and in vitro data suggests that the NKCD motif of Ras is the redox target of superoxide.

The main objective of this project was to determine the mechanism of …

Trehalose Is A Chemical Attractant In The Establishment Of Coral Symbiosis, M. Hagedorn, V. Carter, N. Zuchowicz, M. Phillips, C. Penfield, B. Shamenek, Elizabeth A. Vallen, F. W. Kleinhans, K. Peterson, M. White, P. H. Yancey

Biology Faculty Works

Coral reefs have evolved with a crucial symbiosis between photosynthetic dinoflagellates (genus Symbiodinium) and their cnidarian hosts (Scleractinians). Most coral larvae take up Symbiodinium from their environment; however, the earliest steps in this process have been elusive. Here we demonstrate that the disaccharide trehalose may be an important signal from the symbiont to potential larval hosts. Symbiodinium freshly isolated from Fungia scutaria corals constantly released trehalose (but not sucrose, maltose or glucose) into seawater, and released glycerol only in the presence of coral tissue. Spawning Fungia adults increased symbiont number in their immediate area by excreting pellets of Symbiodinium, and …

Effect Of Adjuvant And Neoadjuvant Anti-Telomerase With Anthracycline Based Chemotherapy On Triple Negative Breast Cancer Cells, Luke T. Pardy

Student Summer Scholars Manuscripts

Breast cancer is the second leading cause of cancer related death in women in the US. In addition, 20% of all breast cancer cases in the U.S. are from the subtype known as Triple-Negative Breast Cancer (TNBC), which is the most aggressive and invasive form of the disease. This type of breast cancer has the worst prognosis, a decreased survival rate, and no targeted therapy. Over the decades, interest in pre- (Neoadjuvant) and post- (Adjuvant) chemotherapy treatments, in the management of TNBC has increased. Therefore, we evaluated the Adjuvant and Neoadjuvant effects of anti-telomerases (BIBR 1532 and GV6) with anthracycline-based …

A Coxiella-Like Endosymbiont Is A Potential Vitamin Source For The Lone Star Tick, Todd A. Smith, Timothy Driscoll, Joseph J. Gillespie, Rahul Raghavan

Biology Faculty Publications and Presentations

Amblyomma americanum (Lone star tick) is an important disease vector in the United States. It transmits several human pathogens, including the agents of human monocytic ehrlichiosis, tularemia, and southern tick-associated rash illness. Blood-feeding insects (Class Insecta) depend on bacterial endosymbionts to provide vitamins and cofactors that are scarce in blood. It is unclear how this deficiency is compensated in ticks (Class Arachnida) that feed exclusively on mammalian blood. A bacterium related to Coxiella burnetii, the agent of human Q fever, has been observed previously within cells of A. americanum. Eliminating this bacterium (CLEAA, Coxiella-like endosymbiont of A. americanum) with antibiotics …

Human Anatomy And Physiology Preparatory Course (1st Edition), Carlos Liachovitzky

Open Educational Resources

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

The organization and functioning of the human organism generally is discussed in terms of different levels of increasing complexity, from the smallest building blocks to the entire body. This Anatomy and Physiology preparatory course covers the foundations on the chemical level, and a basic introduction to cellular level, organ level, and organ system levels. There is also an introduction to homeostasis at the beginning.