Cell Biology Commons^™

A Central Role For Vimentin In Regulating Repair Function During Healing Of The Lens Epithelium, A. S. Menko, B. M. Bleaken, A. A. Libowitz, L. Zhang, Mary Ann Stepp, J. L. Walker

Anatomy and Regenerative Biology Faculty Publications

Mock cataract surgery provides a unique ex vivo model for studying wound repair in a clinically relevant setting. Here wound healing involves a classical collective migration of the lens epithelium, directed at the leading edge by an innate mesenchymal subpopulation of vimentin-rich repair cells. We report that vimentin is essential to the function of repair cells as the directors of the wound-healing process. Vimentin and not actin filaments are the predominant cytoskeletal elements in the lamellipodial extensions of the repair cells at the wound edge. These vimentin filaments link to paxillin-containing focal adhesions at the lamellipodial tips. Microtubules are involved …

Molecular Pap Biomarkers For Cervical Cancer Risk Assessment In Thinprep® Clinical Specimens, Jennifer Taylor

Graduate School of Biomedical Sciences Theses and Dissertations

Approximately 500,000 patients are diagnosed with cervical cancer worldwide each year, thus making it the second most common cause of cancer-related deaths in women. Persistent high-risk human papillomavirus (HR-HPV) infections induce cervical dysplasia by increasing the expression of two viral oncogenes, E6 and E7. Utilization of the Papanicolaous smear test (Pap test) has contributed to a decrease in morbidity and mortality of cervical cancer; however, subjective analysis of cell morphology with a limited amount of cells has led to a substantial rate of false positive and false negative diagnoses. A more objective and sensitive diagnostic tool for the detection of …

Chip-Seq And Rna-Seq Reveal An Amrz-Mediated Mechanism For Cyclic Di-Gmp Synthesis And Biofilm Development By Pseudomonas Aeruginosa, Christopher J. Jones, David Newsom, Benjamin Kelly, Yasuhiko Irie, Laura K. Jennings, Binjie Xu, Dominique H. Limoli, Joe J. Harrison, Matthew R. Parsek, Peter White, Daniel J. Wozniak

Biology Faculty Publications

The transcription factor AmrZ regulates genes important for P. aeruginosa virulence, including type IV pili, extracellular polysaccharides, and the flagellum; however, the global effect of AmrZ on gene expression remains unknown, and therefore, AmrZ may directly regulate many additional genes that are crucial for infection. Compared to the wild type strain, a ΔamrZ mutant exhibits a rugose colony phenotype, which is commonly observed in variants that accumulate the intracellular second messenger cyclic diguanylate (c-di-GMP). Cyclic di-GMP is produced by diguanylate cyclases (DGC) and degraded by phosphodiesterases (PDE). We hypothesized that AmrZ limits the intracellular accumulation of c-di-GMP through transcriptional repression …

Immature Myeloid Cells Promote Tumor Formation Via Non-Suppressive Mechanism, Myrna Lillian Ortiz

USF Tampa Graduate Theses and Dissertations

ABSTRACT

Although there is ample evidence linking chronic inflammation with cancer, the cellular mechanisms involved in early events leading to tumor development remain unclear. Myeloid cells are an intricate part of inflammation. They consist of mature cells represented by macrophages, dendritic cells and granulocytes and a population of Immature Myeloid Cells (IMC), which in healthy individuals are cells in transition to mature cells. There is a substantial expansion of IMC in cancer and many other pathological conditions which is associated with pathologic activation of these cells. As a result, these cells acquire the ability to suppress immune responses and are …

Direct-To-Consumer Genetic Testing In The College Classroom: Knowledge, Attitudes, And Concerns Of Introductory Biology Students, Nicanor Austriaco

Biology Faculty Publications

Pioneered by companies like 23andMe.com, deCODEme.com, and Navigenics.com, direct-to-consumer genetic testing refers to genetic tests that are marketed directly to consumers via television, print media, or the Internet. This kind of testing provides access to a customer’s genetic information without necessarily involving either a medical health care professional or a genetic counselor in the process. In recent years, a course offered to medical and graduate students at Stanford University has included an option for students to undergo personal genotyping, raising the possibility that direct-to-consumer genetic testing could also be incorporated into undergraduate biology courses to enhance student learning. In this …

Deletion Of Aif1 But Not Of Yca1/Mca1 Protects Saccharomyces Cerevisiae And Candida Albicans Cells From Caspofungin-Induced Programmed Cell Death, Nicanor Austriaco, Christopher Chin, Faith Donaghey, Kathrine Helming, Morgan Mccarthy, Stephen Rogers

Biology Faculty Publications

Caspofungin was the first member of a new class of antifungals called echinocandins to be approved by a drug regulatory authority. Like the other echinocandins, caspofungin blocks the synthesis of β(1,3)-D-glucan of the fungal cell wall by inhibiting the enzyme, β(1,3)-D-glucan synthase. Loss of β(1,3)-D-glucan leads to osmotic instability and cell death. However, the precise mechanism of cell death associated with the cytotoxicity of caspofungin was unclear. We now provide evidence that Saccharomyces cerevisiae cells cultured in media containing caspofungin manifest the classical hallmarks of programmed cell death (PCD) in yeast, including the generation of reactive oxygen species (ROS), the …

Candida Albicans Als5p Amyloid In Host-Microbe Interactions: A Ceanorhabditis Elegans Study, Michael Bois

Dissertations, Theses, and Capstone Projects

Candida albicans, a dimorphic fungus and an opportunistic pathogen, possesses a myriad of adherence factors including members of the agglutinin-like sequence (Als) family of mannoproteins. The adhesin Als5p mediates adhesion to many substrates, and is upregulated during commensal interactions, but is downregulated during active C. albicans infections[1]. An amyloid forming core sequence at residues 325-331 has been shown to be important for Als5p function, because a single amino acid substitution at position 326 (V326N) greatly reduces Als5p-mediated adherence[2]. We evaluated the role of Als5p in host-microbe interactions, using Caenorhabditis elegans as a host model and feeding them Saccharomyces cerevisiae expressing …

Polymerase Alpha Components Associate With Telomeres To Mediate Overhang Processing, Raffaella Diotti

Dissertations, Theses, and Capstone Projects

Telomeres consist of TTAGGG repeats, which end with a 3' G-overhang and are bound by a six-protein complex, known as Shelterin. In humans, telomeres shorten at each cell division, unless telomerase is expressed and able to add telomeric repeats to the 3' G-overhang. However, for effective telomere maintenance, the DNA strand complementary to that made by telomerase must be synthesized. In this study, I focused on the Polα/primase complex, in particular the subunits p68 (POLA2, the regulatory subunit) and p180 (Polα, the catalytic subunit), and their potential roles at telomeres. I was able to detect p180, p68 and OBFC1, a …

The Sex Of The Cell Dictates Its Response, Carlos Ganesh Penaloza

Dissertations, Theses, and Capstone Projects

Male and female differences in frequency of occurrence in disease have perplexed scientists for some time. This in part derives from limitations in the systems in which one can evaluate sex differences. At the organismal level, differences can be hidden by a myriad of extensive and complex factors. Additional limitations exist since most biomedical studies are performed almost exclusively on male subjects, as the female hormonal milieu is intrinsically more variable and too troublesome for routine inclusion in research protocols. Research documenting sex differences continues to grow, and while most researchers suggests that sex hormones are at the core of …

Lipid Dependence In Ras-Driven Tumors, Darin Salloum

Dissertations, Theses, and Capstone Projects

Over past decade, metabolic alterations in cancer cells have received a substantial amount of interest. It had been established that cancer cells undergo a significant amount of metabolic alterations, and some of these alterations are similar to those in normal highly proliferative cells. However, it is becoming more apparent that many of the metabolic alterations are specific to particular oncogenic signaling pathways. Although altered metabolic machinery makes cancer cells more efficient at promoting growth when nutrients are supplied at the sufficient amounts, the dependency of cancer cells on particular metabolic reprogramming deems cancer cells susceptible to disruptions within metabolic network. …

Metabolic Checkpoints In Cancer Cell Cycle, Mahesh Saqcena

Dissertations, Theses, and Capstone Projects

Growth factors (GFs) as well as nutrient sufficiency regulate cell division in metazoans. The vast majority of mutations that contribute to cancer are in genes that regulate progression through the G1 phase of the cell cycle. A key regulatory site in G1 is the growth factor-dependent Restriction Point (R), where cells get permissive signals to divide. In the absence of GF instructions, cells enter the quiescent G0 state. Despite fundamental differences between GF signaling and nutrient sensing, they both have been confusingly referred to as R and therefore by definition considered to be a singular event in G1. Autonomy from …

The Effect Of Drying On Desiccation Tolerance And Late Embryogenesis Abundant Protein Gene Expression In Immature Seeds Of Phalaenopsis Amabilis, Huijing Zhu

Masters Theses

Orchidaceae as the most diverse family of flowering plants are endangered due to losing habitats or destruction of their unique symbiotic living style. Long-term seed storage banks can be a solution for threatened plant species but the stored seeds must tolerate extreme drying and cold. This ability is acquired during the last stage (maturation drying) of seed development and is correlated with a decline in water content and expression of the Late Embryogenesis Abundant (LEA) protein genes. Our goal is to investigate if premature orchid seeds can be artificially induced to become desiccation tolerant and the potential role of LEA …

Blockade Of Mast Cell Activation Reduces Cutaneous Scar Formation, Lin Chen, Megan Schrementi, Matthew J. Ranzer, Traci A. Wilgus, Luisa A. Dipietro

Faculty Publications & Research

Damage to the skin initiates a cascade of well-orchestrated events that ultimately leads to repair of the wound. The inflammatory response is key to wound healing both through preventing infection and stimulating proliferation and remodeling of the skin. Mast cells within the tissue are one of the first immune cells to respond to trauma, and upon activation they release pro-inflammatory molecules to initiate recruitment of leukocytes and promote a vascular response in the tissue. Additionally, mast cells stimulate collagen synthesis by dermal fibroblasts, suggesting they may also influence scar formation. To examine the contribution of mast cells in tissue repair, …

The Effects Of Lipoxin A4 (Lxa4) On Neutrophil Biology In Sepsis, Benedict Wu

Graduate School of Biomedical Sciences Theses and Dissertations

During sepsis, neutrophils are inappropriately activated and have prolonged lifespans, thus becoming dysfunctional. Excessive neutrophil activation can lead to tissue injury while neutrophil dysfunction can lead to decreased free radical production and reduced phagocytosis, preventing the host from clearing preexisting infections. Lipoxin A4 (LXA4) is a specialized pro-resolution mediator which reduces neutrophil migration and expression of proinflammatory mediators. Intact neutrophil functions are critical for the host to efficiently clear invading pathogens. The effects of LXA4 on neutrophil function in sepsis have not been established. Using the cecal ligation and puncture (CLP) model of sepsis, LXA4 administered 1 h after sepsis …

The Role Of Mammalian Cyclin C In Stress Response And Thyroid Disease Progression, Kun Wang

Graduate School of Biomedical Sciences Theses and Dissertations

The cellular response to stress involves changes in gene expression programs as well as the remodeling of subcellular organelles including the mitochondria. Important for this study, the mitochondria undergo extensive fragmentation when the cell is exposed to a variety of stressors. The cyclin C-Cdk8 kinase is a highly conserved transcription factor that associates with the RNA polymerase II holoenzyme. Using cyclin C knockout (CCNC^-/-) mouse embryonic fibroblast (MEF) cells, I revealed that cyclin C is required for the extensive mitochondrial fragmentation following treatment with pro-oxidants or the anti-cancer drug cisplatin. However, Cdk8 is not required for this process …

Effects Of Altering The Peroxisomal Redox State In Models Of Degenerative Disease, Courtney Rose Giordano

Wayne State University Dissertations

Peroxisomes are important regulators of cellular redox balance and function as a signaling platform to regulate anti-aging metabolic and communication networks. In addition the organelle has emerged as a major player in maintaining cellular ROS at an optimal level. At such levels, these ROS are involved in initiation of signaling cascades and that produce an array of anti-aging and disease processes. However, as cells age over time, ROS amass within the peroxisome and elsewhere in the cell. This leads to an imbalance in oxidative homeostasis and results in compromised signaling networks. The goal of this dissertation was to treat disease …

Protein 14-3-3 (Ywha) Isoforms And Their Roles In Regulating Mouse Oocyte Maturation, Santanu De

Biology Faculty Books and Book Chapters

The 14-3-3 (YWHA) is a highly conserved, ubiquitously expressed protein family regulating important cellular processes including cell cycle. This work, for the first time, explored the differential expression and roles of 14-3-3 isoforms during mouse oocyte maturation.

All seven mammalian 14-3-3 isoforms were identified in mouse eggs and ovarian follicular cells including oocytes, by Western blotting. Immunocytochemical and immunohistochemical staining confirmed the presence of all 14-3-3 isoforms in oocytes, eggs and ovarian follicles with characteristic similarities and differences in their distributions.

Mammalian oocytes are arrested at meiosis prophase I by an inhibitory phosphorylation on Cyclin-Dependent Kinase I (CDK1), released by …

Regulation Of Nkcc2 Trafficking By Vesicle Fusion Proteins Vamp2 And Vamp3 In The Thick Ascending Limb, Paulo Sebastian Caceres Puzzella

Wayne State University Dissertations

The thick ascending limb (TAL) in the kidney regulates extracellular fluid volume and blood pressure. The Na/K/2Cl cotransporter NKCC2 plays a central role in NaCl absorption by the TAL and blood pressure. NKCC2 trafficking to the apical membrane is a major mechanism to control NKCC2 activity. However, little is known about the proteins that mediate NKCC2 trafficking. Inhibition of the vesicle fusion proteins VAMP2 and VAMP3 blunts the increase in surface NKCC2 expression and NaCl absorption in response to stimulation by cAMP. In other cells, VAMPs mediate fusion of exocytic vesicles with the plasma membrane. Whether VAMP2 and VAMP3 mediate …

Clinical Features And Outcome Of Sporadic Colorectal Carcinoma In Young Patients: A Cross-Sectional Analysis From A Developing Country, Muhammad Nauman Zahir, Eisha Mahpara Azhar, Sobia Rafiq, Kulsoom Ghias, Munira Shabbir-Moosajee

Department of Biological & Biomedical Sciences

Background: Early onset colorectal carcinoma (CRC) is rare and has been hypothesized to be a biologically and clinically distinct entity personifying aggressive disease and worse survival.
Methods: Data for 131 patients was collected by retrospective chart review. Cox proportional hazard model was used to compute prevalence ratios and 95% confidence intervals.
Results: Early onset sporadic CRC accounted for 32% of all CRC treated in the specified time period. The mean age was 33.3 ± 7.9 years and the male to female ratio was 2 : 1. Colon and rectal cancers accounted for 55% and 45% of patients, respectively. 96% of …

Nel Positively Regulates The Genesis Of Retinal Ganglion Cells By Promoting Their Differentiation And Survival During Development, Chizu Nakamoto, Soh-Leh Kuan, Amy Findlay, Elaine Durward, Zhufeng Ouyang, Masaru Nakamoto, Ewa Zakrewska, Takuma Endo

Biology Faculty Publications

For correct functioning of the nervous system, the appropriate number and complement of neuronal cell types must be produced during development. However, the molecular mechanisms that regulate the production of individual classes of neurons are poorly understood. In this study, we investigate the function of the thrombospondin-1–like glycoprotein, Nel (neural epidermal growth factor [EGF]-like), in the generation of retinal ganglion cells (RGCs) in chicks. During eye development, Nel is strongly expressed in the presumptive retinal pigment epithelium and RGCs. Nel overexpression in the developing retina by in ovo electroporation increases the number of RGCs, whereas the number of displaced amacrine …