Biochemistry, Biophysics, and Structural Biology Commons^™

A Force Of Nature: Molecular Mechanisms Of Mechanoperception In Plants, Gabriele B. Monshausen, Elizabeth S. Haswell

Biology Faculty Research

The ability to sense and respond to a wide variety of mechanical stimuli-gravity, touch, osmotic pressure, or the resistance of the cell wall-is a critical feature of every plant cell, whether or not it is specialized for mechanotransduction. Mechanoperceptive events are an essential part of plant life, required for normal growth and development at the cell, tissue, and whole-plant level and for the proper response to an array of biotic and abiotic stresses. One current challenge for plant mechanobiologists is to link these physiological responses to specific mechanoreceptors and signal transduction pathways. Here, we describe recent progress in the identification …

Characterization Of Jak, Stat, And Src Interactions In Head And Neck Squamous Cell Carcinoma, Reshma Jaseja, Reshma Jaseja

Dissertations and Theses (Open Access)

Recurrence of Head and Neck Squamous Cell Carcinoma (HNSCC) is common; thus, it is essential to improve the effectiveness and reduce toxicity of current treatments. Proteins in the Src/Jak/STAT pathway represent potential therapeutic targets, as this pathway is hyperactive in HNSCC and it has roles in cell migration, metastasis, proliferation, survival, and angiogenesis. During short-term Src inhibition, Janus kinase (Jak) 2, and signal transducer and activator of transcription (STAT) 3 and STAT5 are dephosphorylated and inactivated. Following sustained Src inhibition, STAT5 remains inactive, but Jak2 and STAT3 are reactivated following their early inhibition. To further characterize the mechanism of this …

An Ethnobotanical Approach To Finding Antimicrobial Compounds In Wooly Blue Curls (Trichostema Lanatum) Using A Kirby-Bauer Disc Diffusion Assay, Matthew C. Fleming, P. Matthew Joyner

Featured Research

Plants can be an important source of creativity and production of new drugs. In this study, extracts of wooly blue curls (Trichostema lanatum) were made using DMSO and tested for antimicrobial activity on a panel of bacteria commonly found in separate ecological niches. Wooly blue curls (WBC) was chosen due to its being recorded as a strong disinfectant by the Chumash people. It was found that WBC does exhibit antimicrobial activity against gram positive bacteria and not against gram negative bacteria. However, gram negative bacteria with reduced drug efflux function became susceptible to the WBC extract.

Immunomodulatory Activity Of Sambucus Mexicana And Trichostema Lanatum On Lps Stimulated Raw 264.7 Macrophage Cells, Victoria Hester, P. Matthew Joyner

Featured Research

Chumash medicinal plants Sambucus mexicana (Mexican elderberry) and Trichostema lanatum (woolly blue curls) were tested for immunomodulatory activity. Anti-inflammatory effects were determined by treating LPS induced RAW 264.7 macrophage cells with plant extracts and measuring the levels of cytokines: tumor necrosis factor alpha (TNF-alpha) and interleukin 10 (IL-10). We hypothesized that both plants would exert immunomodulatory activity by reducing the pro-inflammatory production of TNF-alpha or by promoting M2 polarization with a concurrent increase in IL-10 production. At concentration 0.01 mg/mL woolly blue curls and Mexican elderberry demonstrated anti-inflammatory activity by reducing the concentration of TNF-alpha in vitro, while levels of …

Role Of Nucleation In Cortical Microtubule Array Organization: Variations On A Theme, Erica A. Fishel, Ram Dixit

Biology Faculty Research

The interphase cortical microtubules (CMTs) of plant cells form strikingly ordered arrays in the absence of a dedicated microtubule-organizing center. Considerable research effort has focused on activities such as bundling and severing that occur after CMT nucleation and are thought to be important for generating and maintaining ordered arrays. In this review, we focus on how nucleation affects CMT array organization. The bulk of CMTs are initiated from γ-tubulin-containing nucleation complexes localized to the lateral walls of pre-existing CMTs. These CMTs grow either at an acute angle or parallel to the pre-existing CMT. Although the impact of microtubule-dependent nucleation is …

Germline Transgenic Methods For Tracking Cells And Testing Gene Function During Regeneration In The Axolotl, Shahryar Khattak, Maritta Schuez, Tobias Richter, Dunja Knapp, Saori L. Haigo, Tatiana Sandoval-Guzmán, Kristyna Hradlikova, Annett Duemmler, Ryan R. Kerney, Elly M. Tanaka

Biology Faculty Publications

The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum(axolotl) that open up the cellular and molecular genetic dissection of regeneration. We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly …

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 …

Regulation Of The Target Of Rapamycin Signaling Pathway In Saccharomyces Cerevisiae, Tammy Pracheil

LSU New Orleans Theses and Dissertations

An integrative, biochemical, genetic, and molecular biology approach utilizing gene manipulation, gene knock outs, plasmid based protein expression, and in vivo protein localization of fluorescence tagged proteins was employed to determine the function of an essential protein, Lst8, in TORC1 and TORC2 signaling and a previously uncharacterized complex, the Far3-7-8-9-10-11 complex (Far complex) in the budding yeast, Saccharomyces cerevisiae. Mutations in SAC7 and FAR11 suppressed lethality of both lst8 and tor2-21 mutations but not TORC1 inactivation, suggesting that the essential function of Lst8 is linked only to TORC2.

Far11, a component of a six-member complex, was found to interact …

Broad Spectrum Systemic Acquired Resistance In Amblystegium Serpens, Christina A. Tatara

Undergraduate Honors Thesis Collection

Systemic acquired resistance (SAR) is a well-characterized defense mechanism in vascular plants where initial exposure to a pathogen induces resistance throughout the plant to subsequent attacks by a wide range of pathogens. A similar SAR-like mechanism has recently been documented in a nonvascular plant, the moss Amblysregium serpens, but it has not been thoroughly characterized. Currently only one pathogen, the oomycete Pythium irregulare, has been shown to trigger SAR in this or any other nonvascular plant. I have observed and characterized the interactions between A. serpens and two other alleged moss pathogens, the ascomycetes Acrosporium sympodiale and Botrytis cinerea. Using …

Patatin-Related Phospholipase Pplaiiiδ Increases Seed Oil Content With Long-Chain Fatty Acids In Arabidopsis, Maoyin Li, Sung Bahn, Chuchuan Fan, Jia Li, Tien Phan, Michael Ortiz, Mary Roth, Ruth Welti, Jan Jaworski, Xuemin Wang

Biology Department Faculty Works

The release of fatty acids from membrane lipids has been implicated in various metabolic and physiological processes, but in many cases, the enzymes involved and their functions in plants remain unclear. Patatin-related phospholipase As (pPLAs) constitute a major family of acyl-hydrolyzing enzymes in plants. Here, we show that pPLAIIId promotes the production of triacylglycerols with 20- and 22-carbon fatty acids in Arabidopsis (Arabidopsis thaliana). Of the four pPLAIIIs (a, b, g, d), only pPLAIIId gene knockout results in a decrease in seed oil content, and pPLAIIId is most highly expressed in developing embryos. The overexpression of pPLAIIId increases the content …

Section Abstracts: Biology With Microbiology And Molecular Biology

Virginia Journal of Science

Abstracts of the Biology with Microbiology and Molecular Biology Section for the 91st Annual Virginia Journal of Science Meeting, May 2013

The Use Of P53-Derived Stapled Peptides As Affinity Isolation Reagents, Kathryn Margaret Headley

Renée Crown University Honors Thesis Projects - All

The transcription factor p53 can induce apoptosis and cell cycle arrest in response to cellular distress. Cancer cells often display increased cell survival. In most cases, this is due to a p53-related defect, such as mutation, deletion, degradation, or sequestration. HDM2 and HDMX are homologous proteins that regulate the function of p53, and their over-expression can lead to an ineffective p53 response. Various inhibitors, including hydrocarbon stabilized alpha-helices of p53 (SAH-p53s), have been developed to target HDM2 and HDMX and restore functionality to the p53 pathway. It has been recently found that SAH-p53 factors also elicit cell death responses in …

Characterization Of Dap2 (Defense-­‐Associated Aspartic Protease-­‐2) In Arabidopsis Thaliana And Determining Its Role In Plant Defense Responses, Kemardo Kitaro Henry

Renée Crown University Honors Thesis Projects - All

Plants defend themselves from invading pathogens by coordinating activity of several plant defense-­‐associated genes. Defense-­‐Associated Aspartic Protease-­‐1 (DAP1) gene of Arabidopsis encodes for an atypical aspartic protease with a putative proteolytic activity. The DAP1 is a negative regulator of plant immunity and the transgenic plants ectopically expressing this genes support pathogen growth and pathogenicity. The Arabidopsis genome has another putative protese that has ~75% homology to DAP1 present in close proximity and therefore was named DAP2. Here, I describe the role of the DAP2 gene in plant defense responses. Two independent knockout dap2 mutants are found to be more susceptible …

Vitamin B12-Based Bioconjugate Probes For In Vitro And In Vivo Imaging, Anna Kahkoska

Renée Crown University Honors Thesis Projects - All

Cancer is the second leading cause of death in the United States. This year, an estimated 577,190 Americans will die as a result of this family of diseases. Finding cancer at its most treatable stage gives patients the greatest chance of recovery; novel imaging agents that target primary and metastasized tumors offer hope for improved prognoses in the future. Based on the hypothesis that vitamin B12 (B12) and its association with specific transport proteins could offer selective access to cancer cell lines, a series of B12-based imaging agents were synthesized, characterized, and assayed for both in vitro and in vivo …

Structural And Functional Studies On The Role Of The Retinoblastoma Binding Protein Five (Rbbp5) In The Histone Methyltransferase Activity Of The Mixed Lineage Leukemia (Mll1) Core Complex, Melody Sanders

Biology - Theses

Cells employ elaborate mechanisms to introduce structural and chemical variation into chromatin in the form of covalent post-translational modifications. Covalent modifications of histones contribute to the dynamic states of chromatin structure that govern nearly all of DNA-coupled processes such as transcription, replication, and repair. The mechanism by which covalent modifications of histones contribute to these activities remains a central question to understanding genome regulation and its dysfunction in human disease. Although there is extensive literature documenting the identification of many of the enzymes that place histone modifications, far less is known about how the enzymes are targeted and how their …

The Effects Of Glutathione And Its Derivatives On The Survival Of Mycobacterium Bovis-Bcg Vegetative And Persistent Organisms, Neil Patel

Honors College Theses

Mycobacterium tuberculosis is responsible for nearly 2 million deaths yearly. Upon inhalation,mycobacteria are engulfed by alveolar macrophages. These cells produce reactive oxygen and nitrogen intermediates (ROI’s and RNI’s), which normally kill pathogens, but are ineffective against invading mycobacteria. What ensues, is the formation of a tubercle to sequester the infected macrophages, and the initiation of a latent tuberculosis infection, in which the mycobacteria enter a state of non-replicative persistence (NRP). Glutathione (GSH), a host tripeptide thiol-based detoxification molecule, protects host cells from ROI/RNI toxicity.Recently, it has been demonstrated that GSH is toxic to in vitro and early infection mycobacteria, but …

Amphetamine Elicits Opposing Actions On Readily Releasable And Reserve Pools For Dopamine, Dan P. Covey, Steven A. Juliano, Paul A. Garris

Faculty Publications – Biological Sciences

Amphetamine, a highly addictive drug with therapeutic efficacy, exerts paradoxical effects on the fundamental communication modes employed by dopamine neurons in modulating behavior. While amphetamine elevates tonic dopamine signaling by depleting vesicular stores and driving non-exocytotic release through reverse transport, this psychostimulant also activates phasic dopamine signaling by up-regulating vesicular dopamine release. We hypothesized that these seemingly incongruent effects arise from amphetamine depleting the reserve pool and enhancing the readily releasable pool. This novel hypothesis was tested using in vivo voltammetry and stimulus trains of varying duration to access different vesicular stores. We show that amphetamine actions are stimulus dependent …

Activities Of Methionine-Γ-Lyase In The Acidophilic Archaeon “Ferroplasma Acidarmanus” Strain Fer1, M. A. Khan, Madeline M. Lopez-Munoz, Charles W. Kaspar, Kai F. Hung

Faculty Research & Creative Activity

Biogeochemical processes on exposed pyrite ores result in extremely high levels of sulfuric acid at these locations. Acidophiles that thrive in these conditions must overcome significant challenges, including an environment with proton concentrations at pH 3 or below. The role of sulfur metabolism in the archaeon “Ferroplasma acidarmanus” strain fer1’s ability to thrive in this environment was investigated due to its growth-dependent production of methanethiol, a volatile organic sulfur compound. Two putative sequences for methionine- γ-lyase (EC 4.4.1.11), an enzyme known to carry out α,γ-elimination on L-methionine to produce methanethiol, were identified in fer1. Bioinformatic analyses identified a conserved pyridoxal-5′-phosphate …

Activities Of Methionine-Γ-Lyase In The Acidophilic Archaeon “Ferroplasma Acidarmanus” Strain Fer1, M. Khan, Madeline Lopez-Munoz, Charles Kaspar, Kai Hung

Faculty Research & Creative Activity

Biogeochemical processes on exposed pyrite ores result in extremely high levels of sulfuric acid at these locations. Acidophiles that thrive in these conditions must overcome significant challenges, including an environment with proton concentrations at pH 3 or below. The role of sulfur metabolism in the archaeon “Ferroplasma acidarmanus” strain fer1’s ability to thrive in this environment was investigated due to its growth-dependent production of methanethiol, a volatile organic sulfur compound. Two putative sequences for methionine- γ-lyase (EC 4.4.1.11), an enzyme known to carry out α,γ-elimination on L-methionine to produce methanethiol, were identified in fer1. Bioinformatic analyses identified a conserved pyridoxal-5′-phosphate …

Novel Architecture Of Costal Cartilage And Implications In Chest Wall Deformities, Anthony J. Asmar

Biological Sciences Theses & Dissertations

Costal cartilage is a type of hyaline cartilage that forms rod-like structures that connect the ribs to the sternum. Deformation of costal cartilage is observed in the chest wall deformities, pectus excavatum and pectus carinatum. Pectus excavatum involves a sternal displacement causing a depression of the chest while pectus carinatum causes a protrusion of the chest. As costal cartilage is not a widely studied tissue, this leaves little knowledge into possible factors involved in the pathogenesis of pectus deformities. Costal cartilage in these deformities has been described as being weakened and may implicate proteoglycans which play an important role in …

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

Honors Capstones

No abstract provided.

Adenosine Triphosphate (Atp) Is A Candidate Signaling Molecule In The Mitochondria-To-Nucleus Retrograde Response Pathway, Feng Zhang, Tammy Pracheil, Janet Thornton, Zhengchang Liu

Biological Sciences Faculty Publications

Intracellular communication from the mitochondria to the nucleus is achieved via the retrograde response. In budding yeast, the retrograde response, also known as the RTG pathway, is regulated positively by Rtg1, Rtg2, Rtg3 and Grr1 and negatively by Mks1, Lst8 and two 14-3-3 proteins, Bmh1/2. Activation of retrograde signaling leads to activation of Rtg1/3, two basic helix-loop-helix leucine zipper transcription factors. Rtg1/3 activation requires Rtg2, a cytoplasmic protein with an N-terminal adenosine triphosphate (ATP) binding domain belonging to the actin/Hsp70/sugar kinase superfamily. The critical regulatory step of the retrograde response is the interaction between Rtg2 and Mks1. Rtg2 binds to …

Dna Damage Repair Genes Controlling Human Papillomavirus (Hpv) Episome Levels Under Conditions Of Stability And Extreme Instability, Terri Edwards, Thomas Vidmar, Kevin Koeller, James Bashkin, Chris Fisher

Chemistry & Biochemistry Faculty Works

DNA damage response (DDR) genes and pathways controlling the stability of HPV episomal DNA are reported here. We set out to understand the mechanism by which a DNA-binding, N-methylpyrrole-imidazole hairpin polyamide (PA25) acts to cause the dramatic loss of HPV DNA from cells. Southern blots revealed that PA25 alters HPV episomes within 5 hours of treatment. Gene expression arrays identified numerous DDR genes that were specifically altered in HPV16 episome-containing cells (W12E) by PA25, but not in HPV-negative (C33A) cells or in cells with integrated HPV16 (SiHa). A siRNA screen of 240 DDR genes was then conducted to identify enhancers …

Isoflurane Increases Neuronal Cell Death Vulnerability By Downregulating Mir-214, Hailiang Yan, Tao Xu, Hongfeng Zhao, Kuo-Chieh Lee, Hoau-Yan Wang, Yan Zhang

Publications and Research

Since accumulating evidence suggests the application of anesthetics may increase the risk of Alzheimer’s disease (AD), we investigated the cytotoxicity of inhaled general anesthesia in neurons and its underlying mechanism. Using primary cultured rat hippocampal neurons as the study model, here we show that isoflurane increases vulnerability to intracellular or extracellular amyloid b with or without serum deprivation. This isoflurane-induced effect is mediated by the downregulation of miR-214 level that lead to an elevated expression of Bax, a prominent target for miR-214. We conclude that isoflurane increases cell death in the presence of amyloid b by increasing Bax level through …

Psychosine, The Cytotoxic Sphingolipid That Accumulates In Globoid Cell Leukodystrophy, Alters Membrane Architecture, Jacqueline Hawkins-Salsbury, Archana Parameswar, Xuntian Jiang, Paul Schlesinger, Ernesto Bongarzone, Daniel Ory, Alexei Demchenko, Mark Sands

Chemistry & Biochemistry Faculty Works

Globoid cell leukodystrophy (GLD) is a neurological disease caused by deficiency of the lysosomal enzyme galactosylceramidase (GALC). In the absence of GALC, the cytotoxic glycosphingolipid, psychosine (psy), accumulates in the nervous system. Psychosine accumulation preferentially affects oligodendrocytes, leading to progressive demyelination and infiltration of activated monocytes/macrophages into the CNS. GLD is characterized by motor defects, cognitive deficits, seizures, and death by 2–5 years of age. It has been hypothesized that psychosine accumulation, primarily within lipid rafts, results in the pathogenic cascade in GLD. However, the mechanism of psychosine toxicity has yet to be elucidated. Therefore, we synthesized the enantiomer of …

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 …

Using Stable Isotope Analysis Of Zooplankton To Document Trophic And Biogeochemical Changes In The San Francisco Estuary, Steven C. Westbrook, Julien Moderan

STAR Program Research Presentations

Zooplankton represent a vital link between phytoplankton and fish, like the endangered Delta Smelt. Human interferences (nitrates from waste water, flow alteration, invasive species introduction…) have altered the structure of the San Francisco Estuary (SFE) ecosystem. We use stable isotope analysis to improve our knowledge of the planktonic food web in the SFE and gain insights into its evolution over the past decades. We use the ratios of certain isotopes (Nitrogen, Carbon, Sulfur, etc.) in different species of zooplankton to tell us what it is feeding on as well as the trophic level it feeds in. My research focused on …

Estrogen Receptor Α Regulates Erk In Mcf-7 Cells, John M. Schmitt, Angela J. Rofelty

Faculty Publications - Department of Biological & Molecular Science

Abstract Estrogen (E2) signaling significantly affects breast tumorigenesis by enhancing cell growth and preventing apoptosis. The actions of estrogen in MCF-7 breast cancer cells are mediated through a kinase pathway involving CaM KK, CaM KI, and ERK. Current research is examining the involvement of the Estrogen Receptor (ER) alpha (α) and beta (β) as well as G-Protein Coupled Receptor GPR30 in cell growth and proliferation. ERα is suggested to be responsible for ERK and perhaps CaM Kinase activation. Our goal was to evaluate if ERα, rather than GPR30 or ERβ, mediates CaM KI and ERK activation upon treatment of MCF-7 …

Acyl-Lipid Metabolism, Younghua Li-Beisson, Basil Shorrosh, Fred Beisson, Mats X. Andersson, Vincent Arondel, Philip D. Bates, Sébastien Baud, David Bird, Allan Debono, Timothy P. Durrett, Rochus B. Franke, Ian A. Graham, Kenta Katayama, Amélie A. Kelly, Tony Larson, Jonathan E. Markham, Martine Miquel, Isabel Molina, Ikuo Nishida, Owen Rowland, Lacey Samuels, Katherine M. Schmid, Hajime Wada, Ruth Welti, Changcheng Xu, Rémi Zallot, John Ohlrogge

Scholarship and Professional Work - LAS

Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes …

Cam Kk Mediates Mdm2 Activation In Lncap Cells, John M. Schmitt, Philip Graber

Faculty Publications - Department of Biological & Molecular Science

Abstract Agonists and hormones that cause an influx of calcium in LNCaP prostate cancer cells activate the calcium/calmodulin-dependent protein kinase (CaM Kinase) pathway and AKT phosphorylation. CaM KK and AKT are essential for promoting LNCaP cell survival. AKT phosphorylation of MDM2 protein may negatively regulate the tumor suppressor protein, p53. CaM KK and AKT have yet to be demonstrated as upstream regulators of MDM2 and p53 in LNCaP cells. Our goals were to examine the ability of carbachol and testosterone to stimulate MDM2 phosphorylation, its association with p53, and whether CaM KK is upstream of MDM2. Stimulation of LNCaP cells …