Cell Biology Commons^™

Investigation Of Multidrug Efflux Transporter Acrb In Escherichia Coli: Assembly, Degradation And Dynamics, Prasangi Irosha Rajapaksha

Theses and Dissertations--Chemistry

The Resistant Nodulation Division (RND) super family member, tripartite AcrA-AcrB-TolC efflux pump, is a major contributor in conferring multidrug-resistance in Escherichia coli. The structure of the pump complex, and drug translocation by functional rotation mechanism have been widely studied. Despite of all these data, the dynamics of the assembly process of the pump and AcrB during functional rotation in the process of drug efflux remains poorly understood. My thesis focuses on understanding the pump assembly process, dynamics of AcrB in functional rotation mechanism, and also investigate the mechanism of degradation of AcrB facilitated by a C-terminal ssrA tag.

In the …

Characterization Of Alcohol-Mediated Promotion Of Breast Cancer Stem Cells, Mckenna Below

Master's Theses

Breast cancer is the leading cause of cancer-related death in women globally, and one in eight women will be diagnosed with breast cancer at some point in her life. Alcohol consumption has been linked to increase breast cancer risk and increased risk of tumor recurrence. Understanding the molecular mechanisms of modifiable lifestyle factors such as alcohol consumption will help to lower these risks and design more effective therapeutic approaches. Estrogen Receptor positive (ER+) breast cancer comprises approximately 70% of all breast cancers, and these tumors are effectively targeted by endocrine therapy in the form of estrogen deprivation with aromatase inhibitors, …

Nucleus Type-Specific Dna Methylomics Reveals Epigenetic “Memory” Of Prior Adaptation In Skeletal Muscle, Yuan Wen, Cory M. Dungan, C. Brooks Mobley, Taylor Valentino, Ferdinand Von Walden, Kevin A. Murach

Health, Human Performance and Recreation Faculty Publications and Presentations

Using a mouse model of conditional and inducible in vivo fluorescent myonuclear labeling (HSA-GFP), sorting purification of nuclei, low-input reduced representation bisulfite sequencing (RRBS), and a translatable and reversible model of exercise (progressive weighted wheel running, PoWeR), we provide the first nucleus type-specific epigenetic information on skeletal muscle adaptation and detraining. Adult (>4 mo) HSA-GFP mice performed PoWeR for 8 wk then detrained for 12 wk; age-matched untrained mice were used to control for the long duration of the study. Myonuclei and interstitial nuclei from plantaris muscles were isolated for RRBS. Relative to untrained, PoWeR caused similar myonuclear CpG …

Cop9 Signalosome Component Csn-5 Promotes Accumulation And Function Of Stem Cell Regulators Fbf-1 And Fbf-2, Emily Osterli

Graduate Student Theses, Dissertations, & Professional Papers

RNA-binding proteins FBF-1 and FBF-2 (FBFs) are required for stem cell maintenance in C. elegans, although the mechanisms by which FBFs protein levels are regulated remain unknown. Using a yeast two-hybrid screen, we identified an interaction between both FBFs and CSN-5, a component of the COP9 (constitutive photomorphogenesis 9) signalosome. This highly conserved COP9 complex can affect protein stability through a range of mechanisms including deneddylation, deubiquitination, and phosphorylation (Wolf et al., 2003). Mapping protein-protein interactions between FBFs and CSN-5 suggested that the MPN (Mpr1/Pad1 N-terminal) metalloprotease domain of CSN-5 interacts with the RNA-binding domain of FBFs at physiologically …

An Investigation Of The Role Of Basigin-Variant-1 In The Immune Response Within The Retina, Abigail D. Tompa

UNF Graduate Theses and Dissertations

The neural retina is considered an immune privileged area, in that the eye attempts to suppress the inflammatory response to preserve vision. If there is damage to the blood-retina barrier, such as in diabetes or macular degeneration, it is possible for monocytes to travel out of the blood vessels and into the retina. While studying retinoblastoma, a research group determined that the protein, Basigin, through its extracellular domain, elicits an immune response by enhancing transcription of the pro-inflammatory cytokine interleukin-6 (IL-6). Basigin is cell adhesion molecule that belongs to the immunoglobulin superfamily. The Basigin gene has two main transcripts, that …

Impact Of Hemodynamic Vortex Spatial And Temporal Characteristics On Analysis Of Intracranial Aneurysms, Kevin W. Sunderland

Dissertations, Master's Theses and Master's Reports

Subarachnoid hemorrhage is a potentially devastating pathological condition in which bleeding occurs into the space surrounding the brain. One of the prominent sources of subarachnoid hemorrhage are intracranial aneurysms (IA): degenerative, irregular expansions of area(s) of the cerebral vasculature. In the event of IA rupture, the resultant subarachnoid hemorrhage ends in patient mortality occurring in ~50% of cases, with survivors enduring significant neurological damage with physical or cognitive impairment. The seriousness of IA rupture drives a degree of clinical interest in understanding these conditions that promote both the development and possible rupture of the vascular malformations. Current metrics for the …

Investigating The Antitumor Effects Of A Dsrna-Nanoparticle Complex In An In Vitro Ovarian Cancer Model, Aaron Lewis

Theses and Dissertations (Comprehensive)

An estimated 1 in 70 women will be diagnosed with ovarian cancer in their lifetime. Despite advanced detection and treatment methods, it remains a silent killer with an expected survival rate of 50%. A developing method in cancer treatment is the use of compounds that stimulate the immune system to aid in the body's fight against the disease. This project focused on the use of the potent immune stimulant double-stranded RNA (dsRNA), commercially available as polyinosinic:polycytidylic acid, poly(I:C), to induce cytotoxicity in two ovarian cancer cell lines; SKOV-3 and OVCAR-3. Some challenges exist with the delivery of dsRNA due to …

Human Retinal Organoids Release Extracellular Vesicles That Regulate Gene Expression In Target Human Retinal Progenitor Cells, Jing Zhou, Miguel Flores‑Bellver, Jianbo Pan, Alberto Benito‑Martin, Cui Shi, Onyekwere Onwumere, Jason Mighty, Jiang Qian, Xiufeng Zhong, Tasmim Hogue, Baffour Amponsah‑Antwi, Linda Einbond, Rajendra Gharbaran, Hao Wu, Bo‑Juen Chen, Zhiliang Zheng, Tatyana Tchaikovskaya, Xusheng Zhang, Hector Peinado, Maria Valeria Canto‑Soler, Stephen Redenti

Publications and Research

The mechanisms underlying retinal development have not been completely elucidated. Extracellular vesicles (EVs) are novel essential mediators of cell‑to‑cell communication with emerging roles in developmental processes. Nevertheless, the identification of EVs in human retinal tissue, characterization of their cargo, and analysis of their potential role in retina development has not been accomplished. Three‑dimensional retinal tissue derived from human induced pluripotent stem cells (hiPSC) provide an ideal developmental system to achieve this goal. Here we report that hiPSC‑derived retinal organoids release exosomes and microvesicles with small noncoding RNA cargo. EV miRNA cargo‑predicted targetome correlates with Gene Ontology (GO) pathways involved in …

Mimicking The Effect Of Prolactin On Stat3/Stat5 Activity In Breast Cancer, Jennifer N. Barbuto, Sarah R. Walker

Honors Theses and Capstones

Signal transducers and activators of transcription (STAT) 3 and 5 are commonly constitutively activated in breast cancer. STAT5 can outcompete STAT3 and reduce cell proliferation and metastasis. STAT5 activation is stimulated by prolactin, a natural hormone that can be harmful at high levels. The aim of this study is to identify some possible previously developed drugs that mimic the effect of prolactin and STAT5 without the added risk in MDA-MB231 breast cancer cells. Using the CLUE database query app and STAT5 up- and downregulation signatures, three drugs (X, K, and M) were chosen based on their similarity in signatures to …

Molecular Signatures Of Sexual Communication In The Phlebotomine Sand Flies, Paul V. Hickner, Nataliya Timoshevskaya, Ronald J. Nowling, Frédéric Labbé, Andrew D. Nguyen, Mary Ann Mcdowell, Carolina N. Spiegel, Zainulabeuddin Syed

Biology Faculty Publications

Phlebotomine sand flies employ an elaborate system of pheromone communication wherein males produce pheromones that attract other males to leks (thus acting as an aggregation pheromone) and females to the lekking males (sex pheromone). In addition, the type of pheromone produced varies among populations. Despite the numerous studies on sand fly chemical communication, little is known of their chemosensory genome. Chemoreceptors interact with chemicals in an organism’s environment to elicit essential behaviors such as the identification of suitable mates and food sources. Thus, they play important roles during adaptation and speciation. Major chemoreceptor gene families, odorant receptors (ORs), gustatory receptors …

Arp2/3-Independent Wave/Scar Pathway And Class Xi Myosin Control Sperm Nuclear Migration In Flowering Plants, Mohammad F. Ali, Umma Fatema, Xiongbo Peng, Samuel W. Hacker, Daisuke Maruyama, Meng-Xiang Sun, Tomokazu Kawashima

Plant and Soil Sciences Faculty Publications

After eukaryotic fertilization, gamete nuclei migrate to fuse parental genomes in order to initiate development of the next generation. In most animals, microtubules control female and male pronuclear migration in the zygote. Flowering plants, on the other hand, have evolved actin filament (F-actin)-based sperm nuclear migration systems for karyogamy. Flowering plants have also evolved a unique double-fertilization process: two female gametophytic cells, the egg and central cells, are each fertilized by a sperm cell. The molecular and cellular mechanisms of how flowering plants utilize and control F-actin for double-fertilization events are largely unknown. Using confocal microscopy live-cell imaging with a …

A Molecular Toolset For The In Vivo Detection Of A Sulfolobus Islandicus Leucyl Trna Synthetase Paralog, Nicholas Michael Bretz

Theses and Dissertations

An ancient and ubiquitous set of enzymes known as the aminoacyl-tRNA synthetases are required for the viability of all organisms. The aminoacyl-tRNA synthetases catalyze the attachment of amino acids onto tRNA molecules. The aminoacylated, or charged, tRNA is then transported and utilized at the ribosome for the synthesis of proteins. The genome of the hyperthermophilic microorganism Sulfolobus islandicus (S. islandicus) harbors a unique leucyl-tRNA synthetase paralog, LeuRS-I, of unknown function. While its duplicate, LeuRS-F, carries out all the classical functions of LeuRS-family enzymes, LeuRS-I fails to charge leucine onto tRNALeu, despite its ability to activate this amino acid and bind …

The Cellular Origin And Molecular Drivers Of Claudin-Low Mammary Cancer, Patrick D. Raedler

Theses & Dissertations

Breast cancers of the claudin-low subtype make up a substantial portion of triple-negative breast cancers and have stem cell-like and mesenchymal features. Although it has been recognized for some time that this breast cancer subtype is highly aggressive and difficult to treat, the molecular drivers and cellular origin of claudin-low breast cancer have been poorly defined. The lack of suitable in vivo models has prohibited the study of tumor initiation and progression of this subtype. In this work, we report two novel mouse models that, upon expression of oncogenic RAS in the mammary epithelium, develop highly metastatic triple-negative mammary tumors …

Mechanisms By Which Mnte-2-Pyp Suppresses Prostate Cancer Cell Growth, Yuxiang Zhu

Theses & Dissertations

Prostate cancer patients are often treated with radiotherapy. MnTE-2-PyP, is a superoxide dismutase (SOD) mimic and a known radioprotector of normal tissues. Our recent work demonstrates that MnTE-2-PyP also inhibits prostate cancer progression with radiotherapy; however, the mechanisms remain unclear. In this thesis, we identified that MnTE-2-PyP-induced intracellular H2O2 levels are critical in inhibiting growth of prostate cancer cells. We found that MnTE-2-PyP induced protein oxidations in PC3 cells and one major group of oxidized protein targets were involved in energy metabolism. The oxidative phosphorylation rates were significantly enhanced in both PC3 and LNCaP cells with MnTE-2-PyP treatment, but mitochondrial …

Single-Fluorophore Sensors For Mechanical Force In Living Cells, Sarah Kricheff

Honors Scholar Theses

Mechanotransduction is the process by which a mechanical stimulus is converted to a cellular signal. This process is heavily influential of cell morphology, differentiation, and behavior. However, altered levels of mechanical stimuli are also found in many pathological contexts. For example, cancerous cells have stiffer surrounding tissue than healthy cells, and research suggests that this alters cell behavior and promotes metastasis. Despite these findings, the cellular processes behind these signaling alterations remain widely unknown. Understanding these cascades is critical, as involved proteins can give us a deeper understanding of the role of mechanotransduction, and certain proteins can potentially be targeted …

K2p2.1 (Trek-1) Potassium Channel Activation Protects Against Hyperoxia-Induced Lung Injury, Tatiana Zyrianova, Benjamin Lopez, Riccardo Olcese, John Belperio, Christopher M. Waters, Leanne Wong, Victoria Nguyen, Sriharsha Talapaneni, Andreas Schwingshackl

Physiology Faculty Publications

No targeted therapies exist to counteract Hyperoxia (HO)-induced Acute Lung Injury (HALI). We previously found that HO downregulates alveolar K_2P2.1 (TREK-1) K⁺ channels, which results in worsening lung injury. This decrease in TREK-1 levels leaves a subset of channels amendable to pharmacological intervention. Therefore, we hypothesized that TREK-1 activation protects against HALI. We treated HO-exposed mice and primary alveolar epithelial cells (AECs) with the novel TREK-1 activators ML335 and BL1249, and quantified physiological, histological, and biochemical lung injury markers. We determined the effects of these drugs on epithelial TREK-1 currents, plasma membrane potential (Em), and intracellular Ca …

Structural Characterization And In Vitro Lipid Binding Studies Of Non-Specific Lipid Transfer Protein 1 (Nsltp1) From Fennel (Foeniculum Vulgare) Seeds, Mekdes Megeressa, Bushra Siraj, Shamshad Zarina, Aftab Ahmed

Pharmacy Faculty Articles and Research

Non-specific lipid transfer proteins (nsLTPs) are cationic proteins involved in intracellular lipid shuttling in growth and reproduction, as well as in defense against pathogenic microbes. Even though the primary and spatial structures of some nsLTPs from different plants indicate their similar features, they exhibit distinct lipid-binding specificities signifying their various biological roles that dictate further structural study. The present study determined the complete amino acid sequence, in silico 3D structure modeling, and the antiproliferative activity of nsLTP1 from fennel (Foeniculum vulgare) seeds. Fennel is a member of the family Umbelliferae (Apiaceae) native to southern Europe and the Mediterranean …

Unconventional Constituents And Shared Molecular Architecture Of The Melanized Cell Wall Of C. Neoformans And Spore Wall Of S. Cerevisiae, Christine Chrissian, Coney Pei-Chin Lin, Emma Camacho, Arturo Casadevall, Aaron M. Neiman, Ruth E. Stark

Publications and Research

The fungal cell wall serves as the interface between the cell and the environment. Fungal cell walls are composed largely of polysaccharides, primarily glucans and chitin, though in many fungi stress-resistant cell types elaborate additional cell wall structures. Here, we use solid-state nuclear magnetic resonance spectroscopy to compare the architecture of cell wall fractions isolated from Saccharomyces cerevisiae spores and Cryptococcus neoformans melanized cells. The specialized cell walls of these two divergent fungi are highly similar in composition. Both use chitosan, the deacetylated derivative of chitin, as a scaffold on which a polyaromatic polymer, dityrosine and melanin, respectively, is assembled. …

A Two-Clone Approach To Study Signaling Interactions Among Neuronal Cells In A Pre-Clinical Alzheimer’S Disease Model, Catherine J. Yeates, Ankita Sarkar, Prajakta Deshpande, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

To understand the progression of Alzheimer's disease, studies often rely on ectopic expression of amyloid-beta 42 (Aβ42) throughout an entire tissue. Uniform ectopic expression of Aβ42 may obscure cell-cell interactions that contribute to the progression of the disease. We developed a two-clone system to study the signaling cross talk between GFP-labeled clones of Aβ42-expressing neurons and wild-type neurons simultaneously generated from the same progenitor cell by a single recombination event. Surprisingly, wild-type clones are reduced in size as compared with Aβ42-producing clones. We found that wild-type cells are eliminated by the induction of cell death. Furthermore, aberrant activation of c-Jun-N-terminal …

Does The Presence Of Multiple Β-Lactamases In Gram-Negative Bacilli Impact The Results Of Antimicrobial Susceptibility Tests And Extended-Spectrum Β-Lactamase And Carbapenemase Confirmation Methods?, Fred C. Tenover, Caitlin M. Dela Cruz, Scott Dewell, Victoria M. Le, Isabella A. Tickler

Biology Faculty Publications

Objectives: Many multidrug-resistant Gram-negative bacilli (MDR-GNB) harbour multiple β-lactamases. The aim of this study was to assess the impact of multiple β-lactamase carriage on the accuracy of susceptibility tests and extended-spectrum β-lactamase (ESBL) and carbapenemase confirmation methods.

Methods: A total of 50 MDR-GNB, of which 29 carried multiple β-lactamases, underwent broth microdilution (BMD) and disk diffusion (DD) testing as well as confirmation tests for ESBLs and carbapenemases. Whole-genome sequencing (WGS) was used for β-lactamase gene identification.

Results: Categorical agreement of BMD and DD testing results ranged from 86.5 to 97.7% for 10 β-lactam agents. BMD and DD algorithms for ESBL …