Biology Commons^™

Use Of Image Cytometry For Quantification Of Pathogenic Fungi In Association With Host Cells, Charlotte A. Berkes, Leo Li-Ying Chan, Alisha Wilkinson, Benjamin Paradis

Biology Faculty Publications

Studies of the cellular pathogenesis mechanisms of pathogenic yeasts such as Candida albicans, Histoplasma capsulatum, and Cryptococcus neoformans commonly employ infection of mammalian hosts or host cells (i.e. macrophages) followed by yeast quantification using colony forming unit analysis or flow cytometry. While colony forming unit enumeration has been the most commonly used method in the field, this technique has disadvantages and limitations, including slow growth of some fungal species on solid media and low and/or variable plating efficiencies, which is of particular concern when comparing growth of wild-type and mutant strains. Flow cytometry can provide rapid quantitative information regarding yeast …

Ontogeny Of Venom Use And Venom Composition In The Western Widow Spider Latrodectus Hesperus, David Roger Nelsen

Loma Linda University Electronic Theses, Dissertations & Projects

I investigated the behavioral ecology of venom and venom use by the western widow spider (Latrodectus hesperus), emphasizing the role of ontogeny. In an introductory paper, I reviewed existing definitions of venom and poison, and refined these by adding a third category of toxic biological secretions: toxungen. These three can be distinguished by mode of toxin delivery and presence of a wound. In the first of four empirical studies, I investigated venom use by adult females in the context of threat assessment. A single brief poke at the lowest threat level elicited primarily avoidance responses ("move" and "retract"), repeated prodding …

Plant Cytoskeleton: Della Connects Gibberellins To Microtubules, Ram Dixit

Biology Faculty Research

A new study reveals that DELLA proteins directly interact with the prefoldin complex, thus regulating tubulin subunit availability in a gibberellin-dependent manner. This finding provides a mechanistic link between the growth-promoting plant hormone gibberellin and cortical microtubule organization.

Associations Between Alcohol Consumption And Fasting Blood Glucose In Young Adults, Julie Ann Lucca

Master's Theses

Current research shows moderate alcohol consumption is associated with decreased risk of diabetes and excessive consumption or binge drinking can cause insulin resistance and diabetes. In 2010, diabetes was the seventh leading cause of death in the United Statesand was responsible for significant health complications: blindness, kidney failure, and limb amputations, and is a large national economic burden. Fasting blood glucose (FBG) is a tool used to help diagnose diabetes. Abnormally high FBG, ≥100 mg/dl, is indicative of diabetes and pre-diabetes. Few studies have observed diabetic prevalence among young adults or college students. Studying young adults can help provide added …

Species Boundaries And Biogeography Of East African Torrent Frogs Of The Genus Petropedetes (Amphibia: Anura: Petropeditidae), Simon P. Loader, F. Sara Ceccarelli, Mark Wilkinson, Michele Menegon, Jean Mariaux, Rafael O. De Sá, Et Al.

Biology Faculty Publications

Based on morphology there are currently three described East African species of torrent frogs belonging to the tropical African genus Petropedetes (P. dutoiti, P. martiennseni and P. yakusini). Taxonomic uncertainties are evident within this group: a putative new species reported from the Nguru Mountains and the species P. yakusini have a fragmented distribution across the Southern Tanzanian highlands. We conducted a molecular systematic study, sampling populations of East African petropedetids occurring in the mountains of Tanzania (P. martiennseni and P. yakusini), to investigate species boundaries and biogeography. Data provide evidence for the recognition of …

Validation Of Antibodies Used To Study Hypoxia Inducible Factors In Two Species Of Fundulus, Jenna D. Hill

LSU New Orleans Theses and Dissertations

Hypoxia inducible factors (HIFs) are transcription factors and the master regulators of oxygen-dependent gene expression in animals. The focus of this thesis is the distribution of HIF protein in tissues of the fish Fundulus heteroclitus and F. grandis, two widespread species that occur in naturally hypoxic waters. Polyclonal antibodies against HIF-1α, HIF-2α, and HIF-3α were tested on proteins made in vitro and on extracts made from several tissues of normoxic and hypoxic fish. Antibodies against HIF-1α and 3α bound specifically to full length protein made in vitro, and produced bands on western blots of nuclear extracts of near …

Pharmacological Inhibition Of Histone Methyltransferase G9a Affects Expression Of Citron Kinase Target Genes In Neural Stem Cells, Nicholas Heliotis

Honors Scholar Theses

Regulated repression of gene expression by post-translational modification of histones is required for normal development. The histone methyltransferase G9a is essential for embryonic development, and we have shown that phosphorylation of G9a by the CitK, a gene required for normal CNS development, gates gene repression and dimethylation of histone H3 at lysine 9 (H3K9me2) in neural progenitors. CitK and G9a co-localize to promoter regions of genes up-regulated in CitK null cells. CitK mutant progenitors lack H3K9me2 at promoter regions of up-regulated genes, and re-expression of CitK restores both repression of gene expression and H3K9me2 occupancy. In this thesis we examine …

A Novel Therapeutic Approach In Breast And Hematopoietic Cancers: Inhibition Of Sh2-Domain Containing Inositol 5' Phosphatase (Ship), Amamda Balch

Renée Crown University Honors Thesis Projects - All

Aberrant hyperactivation of the phosphatidylinositol 3-kinase (PI3K) cell-signaling pathway, one of the most prominent cell growth, proliferation and survival pathways in the human body, has been observed in many forms of cancer. Upon deregulation, this pathway can facilitate the evasion of programmed cell death, the stimulation of autonomous growth, and the evasion of regular growth-inhibitory signals. While it was initially believed that the dephosphorylation activity of lipid phosphatases served to counteract the pathway by hydrolyzing phosphatidylinositol(3,4,5)trisphosphate (PtdIns(3,4,5)P₃) to phosphatidylinositol(4,5)bisphosphate (PtdIns(4,5)P₂), emerging evidence suggests that SH2-domain containing inositol 5’ phosphatase 1 and 2 (SHIP1/2) may in fact …

In Vitro Characterization Of Avian Influenza Virus Isolates With A Truncated Ns1 Gene Segment, Aaron Dick

Honors Scholar Theses

Avian Influenza Virus represents a significant threat to the world poultry population, and is a potential threat to humans due to the possibility of cross-species AIV infection. Our approach is to characterize a number of avian virus populations with respect to their content of biologically active particles that include hemagglutinating particles (HAP), plaque forming particles (PFP), interferon inducing particles (IFP), interferon induction-suppressing particles (ISP), defective-interfering particles (DIP), cell-killing particles (CKP) and non-infectious cell killing particles (niCKP) using unique in vitro assays developed for avian influenza virus in the Marcus-Sekellick Laboratory. Specifically, we will use a strain of Avian influenza virus, …

Unexpected Phylogenetic Positions Of The Genera Rupirana And Crossodactylodes Reveal Insights Into The Biogeography And Reproductive Evolution Of Leptodactylid Frogs, Antoine Foquet, Boris Leonardo Blotto, Maximiliano Manuel Maronna, Vanessa Kruth Verdade, Flora Acuña Juncá, Rafael O. De Sá, Miguel Trefaut Rodrigues

Biology Faculty Publications

Despite major progress in deciphering the amphibian tree of life by molecular phylogenetics, we identified two questions remaining to be answered regarding relationships within Hyloidea, the clade of South American origin that comprises most extant anuran diversity. A few genera like Rupirana and Crossodactylodes have enigmatic phylogenetic positions, and relationships among major lineages within some families like Leptodactylidae remain ambiguous. To resolve these specific questions we used two approaches (1) a complete matrix approach representing >6.6 kb, including most major Hyloidea lineages (61 terminals) combining different methods of phylogenetic reconstruction and measures of node support; and (2) a supermatrix approach …

Acceleration Of The Panin Development In Mice Expressing Oncogenic K-Ras Due To A High Fat Diet, Bincy Philip

Dissertations and Theses (Open Access)

Obesity is postulated to be one of the major risk factors for pancreatic cancer, and recently it was indicated that an elevated body mass index (BMI correlates strongly with a decrease in patient survival. Despite the evident relationship, the molecular mechanisms involved are unclear. Oncogenic mutation of K-Ras is found early and is universal in pancreatic cancer. Extensive evidence indicates oncogenic K-Ras is not entirely active and it requires a triggering event to surpass the activity of Ras beyond the threshold necessary for a Ras-inflammation feed-forward loop. We hypothesize that high fat intake induces a persistent low level inflammatory response …

Investigating The Roles Of The P63 Isoforms In The Microrna Biogenesis Pathway, Deepavali Chakravarti

Dissertations and Theses (Open Access)

MicroRNAs play roles in various biological processes like development, tumorigenesis, metastasis and pluripotency. My thesis work has demonstrated roles for p63, a p53 family member, in the upstream regulation of microRNA biogenesis. The p63 gene has a complex gene structure and has multiple isoforms. The TAp63 isoforms contain an acidic transcription activation domain. The ΔNp63 isoforms, lack the TA domain, but have a proline rich region critical for gene transactivation. To understand the functions of these isoforms, the Flores lab generated TAp63 and ΔNp63 conditional knock out mice. Using these mice and tissues and cells from these mice we have …

Cellular Life Beyond An Individual’S Death, Emily Schmitt

CAHSS Intellectual Conversations

One of the most famous examples of cell lines surviving long after a person has died comes from a tumor found in the body of Henrietta Lacks, who died of cervical cancer in 1950. The study of approximately 50 million tons of her cells, which would conservatively equal the amount of cells in one billion people, has resulted in nearly 11,000 patents, including the polio vaccine. These cells have become a focus of public attention since Rebecca Skloot’s 2010 book, The Immortal Life of Henrietta Lacks. This talk will discuss what happens to cells once they leave our bodies, …

Evidence For The Requirement Of 14-3-3eta (Ywhah) In Meiotic Spindle Assembly During Mouse Oocyte Maturation, Santanu De, Douglas Kline

Biology Faculty Articles

Background

The 14-3-3 (YWHA) proteins are central mediators in various cellular signaling pathways regulating development and growth, including cell cycle regulation. We previously reported that all seven mammalian 14-3-3 isoforms are expressed in mouse oocytes and eggs and that, 14-3-3η (YWHAH) accumulates and co-localizes in the region of meiotic spindle in mouse eggs matured in vivo. Therefore, we investigated the role of 14-3-3η in spindle formation during mouse oocyte maturation.

Results

Examination of oocytes matured in vitro demonstrated that 14-3-3η accumulates in both meiosis I and II spindles. To explore if 14-3-3η interacts directly with α-tubulin in meiotic spindles, …

Effects Of Synthetic Histone Deacetylase Inhibitors On 3t3l1 Preadipocyte Adipogenic Differentiation Potential, Vikramjeet Singh

Honors Capstones

No abstract provided.

Metabolic Rescue Of “Glucose Addicted” Cancer Cells In Vitro, Paolo Vignali

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Transformations in the glycolytic metabolism of neoplasms modulate their robust cellular division. This characteristic leads to an “addiction” to glucose for continued proliferation and viability. This study investigated whether glucose metabolites could rescue cellular viability in glucose-starvation conditions, a model of the inter-tumoral nutrient-deficient environment. Findings illustrated potential cellular viability rescue with pyruvate addition in glucose-deprived conditions, yet the same potential was not observed with lactic acid, a metabolite that exists at characteristically high concentrations within the intertumoral microenvironment. These results could implicate a predominance of certain metabolic pathways in nutrient-starved cells. Molecular transport capacities across plasma membranes are tied …

Matrix Adhesion Polarizes Heart Progenitor Induction In The Invertebrate Chordate Ciona Intestinalis, J. Norton, J. Cooley, A. Islam, C. D. Cota, Bradley Justin Davidson , '91

Biology Faculty Works

Cell-matrix adhesion strongly influences developmental signaling. Resulting impacts on cell migration and tissue morphogenesis are well characterized. However, the in vivo impact of adhesion on fate induction remains ambiguous. Here, we employ the invertebrate chordate Ciona intestinalis to delineate an essential in vivo role for matrix adhesion in heart progenitor induction. In Ciona pre-cardiac founder cells, invasion of the underlying epidermis promotes localized induction of the heart progenitor lineage. We found that these epidermal invasions are associated with matrix adhesion along the pre-cardiac cell/epidermal boundary. Through targeted manipulations of RAP GTPase activity, we were able to manipulate pre-cardiac cell-matrix adhesion. …

Microbial Biomineralization Of Iron, Wen Fang

Dissertations and Theses

Iron is a common cation in biomineral sand; it is present for example in magnetite produced by magnetotactic bacteria and in iron sulfides produced by sulfate reducing microorganisms. The work presented in this thesis focused on two types of microorganisms capable of forming iron biominerals. In the first project I have studied the effect of O2 on the respiratory physiology and the formation of magnetosomes by Magnetospirillum magneticum AMB-1. In the second project I have studied the relationship between olivine and the activity of dissimilatory sulfate reducing (DSR) microorganisms. For the first project, I grew cells of AMB-1 in cultures …

Immobile Myosin-Ii Plays A Scaffolding Role During Cytokinesis In Budding Yeast, C. Wloka, Elizabeth Ann Vallen, Lydia Thé , '08, X. Fang, Y. Oh, E. Bi

Biology Faculty Works

Core components of cytokinesis are conserved from yeast to human, but how these components are assembled into a robust machine that drives cytokinesis remains poorly understood. In this paper, we show by fluorescence recovery after photobleaching analysis that Myo1, the sole myosin-II in budding yeast, was mobile at the division site before anaphase and became immobilized shortly before cytokinesis. This immobility was independent of actin filaments or the motor domain of Myo1 but required a small region in the Myo1 tail that is thought to be involved in higher-order assembly. As expected, proteins involved in actin ring assembly (tropomyosin and …

Changes In Natural Killer Cell Activation And Function During Primary Hiv-1 Infection, Vivek Naranbhai, Marcus Altfeld, Salim S. Abdool Karim, Thumbi Ndung’U, Quarraisha Abdool Karim, William H. Carr

Publications and Research

Background: Recent reports suggest that Natural Killer (NK) cells may modulate pathogenesis of primary HIV-1 infection. However, HIV dysregulates NK-cell responses. We dissected this bi-directional relationship to understand how HIV impacts NK-cell responses during primary HIV-1 infection.

Methodology/Principal Findings: Paired samples from 41 high-risk, initially HIV-uninfected CAPRISA004 participants were analysed prior to HIV acquisition, and during viraemic primary HIV-1 infection. At the time of sampling post-infection five women were seronegative, 11 women were serodiscordant, and 25 women were seropositive by HIV-1 rapid immunoassay. Flow cytometry was used to measure NK and T-cell activation, NK-cell receptor expression, cytotoxic and cytokine-secretory functions, …

Long-Term Data For Endemic Frog Genera Reveal Potential Conservation Crisis In The Bale Mountains, Ethiopia, David J. Gower, Roman K. Aberra, Silvia Schwaller, Malcolm J. Largen, Ben Collen, Stephen Spawls, Michele Menegon, Breda M. Zimkus, Rafael O. De Sá, Et Al.

Biology Faculty Publications

Populations of many frogs have declined alarmingly in recent years, placing nearly one third of the > 6,000 species under threat of extinction. Declines have been attributed largely to habitat loss, environmental degradation and/or infectious diseases such as chytridiomycosis. Many frogs undergo dramatic natural population fluctuations such that long-term data are required to determine population trends without undue influence of stochastic factors. We present long-term quantitative data (individuals encountered per person hour of searching) for four monotypic frog genera endemic to an Afromontane region of exceptional importance but growing conservation concern: one endemic to the Ethiopian highlands (Spinophrynoides osgoodi) and three …

Detection Of Viable Microorganisms Using Propidium Monoazide, Erik J. Mcfarland, Adrian Ponce Dr.

STAR Program Research Presentations

Propidium monoazide (PMA) is a molecular tool used to assess viability of microorganisms. Currently, PMA is thought to discern viability through membrane permeability; PMA enters only membrane compromised cells, irreversibly crosslinks to theirDNAand precipitates theDNAout of solution, preventing it from being amplified during polymerase chain reaction (PCR). Using PMA on a sample of live and dead microorganisms results in only theDNAof living organisms being amplified and identified. Therefore, a comparison ofPCRresults with and without PMA allows one to determine the live fraction and total population, respectively.

Current literature provides conflicting evidence as to the effectiveness of the technique. Our research …

A Role For Dynamin-Dependent Endocytosis During Drosophila Gastrulation, Marissa Kay Kuhl

Electronic Theses and Dissertations

Gastrulation, a process conserved among many higher organisms, is the directed migration of cells into layers that will establish various tissues targeted to become anatomical structures. This process is accomplished through another conserved morphogenetic event, known as cell intercalation. Early in development, this movement of cells within an organized tissue leads to unique cellular arrangements where neighboring cells contract their shared interfaces in order to meet at a shared vertex. In this thesis, I present work that demonstrates a requirement for Dynamin-dependent endocytosis during these contraction events. Using quantitative analysis, I have identified varied cell behaviors during experiments which knockdown …

Hydraphiles: A Rigorously Studied Class Of Synthetic Channel Compounds With In Vivo Activity, Saeedeh Negin, Bryan Smith, Alexandra Unger, W. Leevy, George Gokel

Chemistry & Biochemistry Faculty Works

No abstract provided.

Comparison Of Th1 Cytokines And T Cell Markers Gene Expressions Between Virulent And An Attenuated Eiav Vaccine Strain, Talia R. Henkle

Lewis Honors College Capstone Collection

The equine infectious anemia virus (EIAV) is closely related to HIV and has been used as a model to identify protective mechanisms against lentivirus infection. In horses, EIA infection progresses for about a year before infected horses manage to control virus replication. This naturally-gained protection is absolutely dependent on active immune responses as evidenced by the fact that immunosuppressive drugs can induce the recurrence of disease. As the resolution of initial viremia correlates with the appearance of virus specific cytotoxic T lymphocytes (CTL), we believe that cellular immune responses play a key role in controlling EIAV in the horse. In …

Matrix Gla Protein Reinforces Angiogenic Resolution, Bikram Sharma, Allan R. Albig

Biology Faculty Publications and Presentations

Matrix Gla Protein (MGP) is an ECM molecule commonly associated with dysfunctions of large blood vessels such as arteriosclerosis and atherosclerosis. However, the exact role of MGP in the microvasculature is not clear. Utilizing a mouse MGP knockout model we found that MGP suppresses angiogenic sprouting from mouse aorta restricts microvascular density in cardiac and skeletal muscle, and is an endogenous inhibitor of tumor angiogenesis. Similarly, morpholino based knockdown of MGP in zebrafish embryos caused a progressive loss of luminal structures in intersegmental vessels, a phenotype reminiscent of Dll4/Notch inhibition. Accordingly, MGP suppressed Notch-dependent Hes-1 promoter activity and expression of …

Pushing Taxonomy To Extiction?, Alessandro Minelli, Annemarie Ohler, Erna Aescht, Aaron Bauer, Lucio Bonato, Roger Bour, Marcelo Rodrigues De Carvalho, Rafael O. De Sá, Et Al.

Biology Faculty Publications

Can we describe all species on Earth before they disappear? We argue that this is possible only by endowing taxonomy with professional manpower and appropriate material resources as required by big science.

Contrary to Costello et al.’s (CMS) (1) statements, taxonomy is not an easy discipline accessible to all through a smartphone. It requires exhaustive training and long familiarity with field, specimens and literature (2).

CMS’s argument is framed in terms of species numbers, but different, non-overlapping species concepts apply to bacteria, brambles and birds (3,4,5): “the species” as common unit of biodiversity does not exist (6).

Even ignoring this …

Characterizing The Effects Of Glutaraldehyde On The Ryanodine Receptor Calcium Release Channel, Joshua Dov Strauss

Legacy Theses & Dissertations (2009 - 2024)

Ryanodine receptors (RyR) are large intracellular calcium release channels, which

Post-Translational Modification Regulates Heterogeneous Nuclear Ribonucleoprotein K Function During Axon Outgrowth In Xenopus Laevis, Erica J. Hutchins

Legacy Theses & Dissertations (2009 - 2024)

The RNA-binding protein, heterogeneous nuclear ribonucleoprotein K (hnRNP K), is required for axon outgrowth. Its suppression in Xenopus embryos causes defects in the translation of mRNAs of multiple cytoskeletal genes. Studies in cell lines have established that hnRNP K shuttles between the nucleus and the cytoplasm to bind and regulate the fates of its target RNAs, from splicing to export and translation. At each step, hnRNP K is regulated through post-translational modifications that alter its nucleic acid and protein interactions, and subcellular localization. Precisely how this happens in developing neurons to coordinate cytoskeletal gene expression with the extracellular signals directing …

Defining The Mechanism Of Enhanced Cellular Invasion Induced By Mechanical Stimulation, Snehal Sunil Ozarkar

Wayne State University Theses

Metastasis is a multistep process driven by various biochemical and mechanical factors, which eventually leads to formation of secondary tumors. The tumor mass is surrounded by basement membrane (BM) and stroma made of various extracellular matrix (ECM) proteins. During metastasis tumor cells disseminate from the primary tumor, breach the BM, invade the stroma, travel through blood and lymph and colonize tissues distant from the primary tumor. Formation of secondary tumors by metastasis is a leading cause of death in cancer patients. Even though plenty of research has been focused on biochemical factors affecting metastasis, information on role of mechanical factors …