Biochemistry, Biophysics, and Structural Biology Commons^™

Lineage-Specific Transcriptional Profiles Of Symbiodinium Spp. Unaltered By Heat Stress In A Coral Host, Daniel J. Barshis, Jason T. Ladner, Thomas A. Oliver, Stephen R. Palumbi

Biological Sciences Faculty Publications

Dinoflagellates of the genus Symbiodinium form an endosymbiosis with reef building corals, in which photosynthetically derived nutrients comprise the majority of the coral energy budget. An extraordinary amount of functional and genetic diversity is contained within the coral-associated Symbiodinium, with some phylotypes (i.e., genotypic groupings), conferring enhanced stress tolerance to host corals. Recent advances in DNA sequencing technologies have enabled transcriptome-wide profiling of the stress response of the cnidarian coral host; however, a comprehensive understanding of the molecular response to stress of coral-associated Symbiodinium, as well as differences among physiologically susceptible and tolerant types, remains largely unexplored. Here, …

Culturable Aerobic And Facultative Anaerobic Intestinal Bacterial Flora Of Black Cobra (Naja Naja Karachiensis) In Southern Pakistan, Junaid Iqbal, Mehwish Sagheer, Nazneen Tabassum, Ruqaiyyah Siddiqui, Naveed Ahmed Khan

Department of Biological & Biomedical Sciences

Using morphological analysis and biochemical testing, here for the first time, we determined the culturable gut bacterial flora (aerobes and facultative anaerobes) in the venomous Black Cobra (Naja naja karachiensis) from South Asia. The findings revealed that these snakes inhabit potentially pathogenic bacteria including Serratia marcescens, Pseudomonas aeruginosa, Shewanella putrefaciens, Aeromonas hydrophila, Salmonella sp., Moraxella sp., Bacillus sp., Ochrobactrum anthropi, and Providencia rettgeri. These findings are of concern, as injury from snake bite can result in wound infections and tissue necrosis leading to sepsis/necrotizing fasciitis and/or expose consumers of snake meat/medicine in the community to infections.

Optimization Of A Chemical Genetic Screen To Identify Druggable Targets In U138 Cells Treated With Laromustine, Kathryn Coe

Honors Theses

Laromustine is an experimental sulfonylhydrazine prodrug used in late-stage clinical studies against acute myeloid leukemia (AML) and glioblastoma multiforme (GBM). Despite initial promise for both indications, clinical trials for GBM have not been as successful as those for AML. To investigate methods for improving the effectiveness of laromustine in GBM and to learn more about the mechanism of action of laromustine, a chemical genetic screen will be conducted to identify agents that sensitize GBM cells to the anti-proliferative effects of laromustine. The library, which will include approximately 450 FDA-approved drugs, will be screened using a newly optimized high throughput assay …

Characterization Of The Transporter Protein Sodium-Potassium Adenosine Triphosphatase In The Myelin Membrane, Dara E C Schaefer

Theses and Dissertations (Comprehensive)

Sodium-potassium adenosine triphosphatase (Na⁺/K⁺-ATPase) is an integral membrane protein with known involvement in the maintenance of resting membrane potentials, nutrient uptake, cellular signal transduction, and cell-cell adhesion. The functional enzyme contains a catalytic alpha subunit and a glycosylated beta subunit, of which three isoforms of each are known to exist in the central nervous system (CNS). Altered expression and/or activity of Na⁺/K⁺-ATPase subunit isoforms has been previously implicated in the pathophysiology of several neurological disorders. This study characterized Na⁺/K⁺-ATPase expression and distribution in the myelin membrane, identified its …

Do The Inter-Nucleotide Domain Loops Act As An Entropic Sink In The Catalytic Activity Of 3-Phosphoglycerate Dehydrogenase (3pgdh)?, Cristina Adelia Meeham

Honors Theses

In protein science the relationship between protein dynamics and catalytic activity are the subject of considerable contemporary interest. Although protein motions are frequently observed during ligand binding and release steps, the contribution of protein motions to the catalysis of bond making/breaking processes is more difficult to probe and verify. Currently, the field of protein science is trying to uncover the deeper role that dynamics plays in the catalytic activity and allosteric regulation of proteins and to better understand how to more effectively and efficiently target proteins in cancer therapeutics and other metabolic pathways.

One-Pot Heteroconjugate Addition-Diels-Alder Reactions And Acetate-Catalyzed Aldol Reactions Of Α-Silyl Nitriles, Carly Mueller

Honors Theses

1. A one-pot three-step Diels–Alder reaction sequence of ethyl propiolate and thiols can be performed to produce high yields of complex bicyclic products. A KOt-Bu-catalyzed thioconjugate addition of thiols to enoates, oxidation of the generated thioenoate by mCPBA, and Li-catalyzed Diels–Alder addition of cyclopentadiene occur in situ, without any purification of intermediates.
2. Stereoselectivity of the Diels–Alder product was examined by utilizing a chiral sulfone substrate. It was determined that these substrates were unable to provide significant stereochemical control.
3. Silylation of 3-phenylpropionitrile is achieved at the α-position with trimethylsilyl trifluoromethanesulfonate and trialkylamine base. Catalyzed by tetrabutylammonium acetate (2.5 mol%), …

A Conservative Isoleucine To Leucine Mutation Of Klentaq1 Dna Polymerase 1 Induces Conformational Change For Cold-Sensitive Phenotype, Emma Caroline Materne

Honors Theses

Polymerase Chain Reaction (PCR) typically employs the Taq or Klentaq1 DNA polymerase from Thermus aquaticus to elongate short sequences of DNA during DNA amplification. Both Taq and Klentaq1 retain activity at room temperature. During assembly of PCR at room temperature, the activity of Taq and Klentaq1 can result in spurious products due to elongation of primers bound to non-target sequences. A mutation of isoleucine to leucine at position 707 of Klentaq1 results in slowing of the enzyme at room temperature without compromising the fidelity of the enzyme. To understand how a mutation over 20Å from the active site can affect …

Formyl Group Activation Of Bromopyrrole Suzuki Cross-Coupling: Application To A Formal Synthesis Of Lamellarin G Trimethyl Ether, Andrew Harrison

Honors Theses

Many biologically interesting compounds have been isolated from marine natural products, many of which contain characteristic pyrroles. Compounds such as polycitones, storniamides, ningalins, and lamellarins have been of particular interest for synthesis due to their vast pharmaceutical potential including the ability to fight tumors as well as induce cytolysis of drug resistant cancer cell lines. Previous studies on the synthesis of Lamellarin G trimethyl ether by the Gupton Group have relied upon vinylogous amide derivatives as building blocks.2 A new pathway utilizing a formylated pyrrole ring provides an interesting method for the synthesis of Lamellarin G trimethyl ether. Regioselective Suzuki …

A Loose Domain Swapping Organization Confers A Remarkable Stability To The Dimeric Structure Of The Arginine Binding Protein From Thermotoga Maritima, Alessia Ruggiero, Jonathan D. Dattelbaum, Maria Staiano, Rita Berisio, Sabato D'Auria, Luigi Vitagliano

Chemistry Faculty Publications

The arginine binding protein from Thermatoga maritima (TmArgBP), a substrate binding protein (SBP) involved in the ABC system of solute transport, presents a number of remarkable properties. These include an extraordinary stability to temperature and chemical denaturants and the tendency to form multimeric structures, an uncommon feature among SBPs involved in solute transport. Here we report a biophysical and structural characterization of the TmArgBP dimer. Our data indicate that the dimer of the protein is endowed with a remarkable stability since its full dissociation requires high temperature as well as SDS and urea at high concentrations. In order to elucidate …

Distribution And Elimination Of 3-Trifluoromethyl-4-Nitrophenol (Tfm) By Sea Lamprey (Petromyzon Marinus) And Non-Target, Rainbow Trout (Oncorhynchus Mykiss) And Lake Sturgeon (Acipenser Fulvescens), Michael W. Le Clair

Theses and Dissertations (Comprehensive)

The pesticide, 3-trifluoromethyl-4-nitrophenol (TFM), has been highly successful in the control of sea lamprey (Petromyzon marinus) populations in the Great Lakes. Treatments with TFM involve applying it to streams, where it targets larval sea lamprey which live burrowed in the stream substrate. While the toxic mechanism of TFM has been elucidated, and its effects on sea lamprey described, its effects on non-target fish species such as rainbow trout (Oncorhynchus mykiss) and lake sturgeon (Acipenser fulvescens) are not as well understood. The present work demonstrated that rainbow trout show a great capacity to detoxify the lampricide using glucuronidation, when exposed to …

The Benefits Of Breastfeeding, Avery Kordus

Senior Honors Theses

Breastfeeding research is plentiful, and the majority of the literature shows that breast milk is the superior form of infant nutrition except in the rare circumstances of infant metabolic disorders, maternal drug use, or positive HIV status. In comparison to formula, breast milk provides improved cognition, development, behavior, bonding, nutrition, digestion, immunity, and long-term health with fewer diseases and conditions in infants. Mothers are benefited by breastfeeding through bonding, faster weight loss, and reduction in certain cancers and conditions. Breast milk contains the proper amount of carbohydrates, fats, proteins, vitamins, and minerals, and is also specialized for each infant and …

Evaluations Of A Mechanistic Hypothesis For The Influence Of Extracellular Ions On Electroporation Due To High-Intensity, Nanosecond Pulsing, V. Sridhara, R. P. Joshi

Electrical & Computer Engineering Faculty Publications

The effect of ions present in the extracellular medium on electroporation by high-intensity, short-duration pulsing is studied through molecular dynamic simulations. Our simulation results indicate that mobile ions in the medium might play a role in creating stronger local electric fields across membranes that then reinforce and strengthen electroporation. Much faster pore formation is predicted in higher conductivity media. However, the impact of extracellular conductivity on cellular inflows, which depend on transport processes such as electrophoresis, could be different as discussed here. Our simulation results also show that interactions between cations (Na+ in this case) and the carbonyl oxygen of …

Numerical Study Of Lipid Translocation Driven By Nanoporation Due To Multiple High-Intensity, Ultrashort Electrical Pulses, Viswanadham Sridhara, Ravindra P. Joshi

Electrical & Computer Engineering Faculty Publications

The dynamical translocation of lipids from one leaflet to another due to membrane permeabilization driven by nanosecond, high-intensity (>100 kV/cm) electrical pulses has been probed. Our simulations show that lipid molecules can translocate by diffusion through water-filled nanopores which form following high voltage application. Our focus is on multiple pulsing, and such simulations are relevant to gauge the time duration over which nanopores might remain open, and facilitate continued lipid translocations and membrane transport. Our results are indicative of a N^1/2 scaling with pulse number for the pore radius. These results bode well for the use of pulse …

Microfluidic Electrical Sorting Of Particles Based On Shape In A Spiral Microchannel, John Dubose, Xinyu Lu, Saurin Patel, Shizhi Qian, Sang Woo Joo

Mechanical & Aerospace Engineering Faculty Publications

Shape is an intrinsic marker of cell cycle, an important factor for identifying a bioparticle, and also a useful indicator of cell state for disease diagnostics. Therefore, shape can be a specific marker in label-free particle and cell separation for various chemical and biological applications. We demonstrate in this work a continuous-flow electrical sorting of spherical and peanut-shaped particles of similar volumes in an asymmetric double-spiral microchannel. It exploits curvature-induced dielectrophoresis to focus particles to a tight stream in the first spiral without any sheath flow and subsequently displace them to shape-dependent flow paths in the second spiral without any …

An Unexpected Particle Oscillation For Electrophoresis In Viscoelastic Fluids Through A Microchannel Constriction, Xinyu Lu, Saurin Patel, Meng Zhang, Sang Woo Joo, Shizhi Qian, Amod Ogale, Xiangchun Xuan

Mechanical & Aerospace Engineering Faculty Publications

Electrophoresis plays an important role in many applications, which, however, has so far been extensively studied in Newtonian fluids only. This work presents the first experimental investigation of particle electrophoresis in viscoelastic polyethylene oxide (PEO) solutions through a microchannel constriction under pure DC electric fields. An oscillatory particle motion is observed in the constriction region, which is distinctly different from the particle behavior in a polymer-free Newtonian fluid. This stream-wise particle oscillation continues until a sufficient number of particles form a chain to pass through the constriction completely. It is speculated that such an unexpected particle oscillating phenomenon is a …

Cellular Regulation Of Extension And Retraction Of Pseudopod-Like Blebs Produced By Nanosecond Pulsed Electric Field, Mikhail A. Rassokhin, Andrei G. Pakhomov

Bioelectrics Publications

Recently we described a new phenomenon of anodotropic pseudopod-like blebbing in U937 cells exposed to nanosecond pulsed electric field (nsPEF). In Ca²⁺ -free buffer such exposure initiates formation of pseudopod-like blebs (PLBs), protrusive cylindrical cell extensions that are distinct from apoptotic and necrotic blebs. PLBs nucleate predominantly on anode-facing cell pole and extend toward anode during nsPEF exposure. Bleb extension depends on actin polymerization and availability of actin monomers. Inhibition of intracellular Ca²⁺ , cell contractility, and RhoA produced no effect on PLB initiation. Meanwhile, inhibition of WASP by wiskostatin causes dose-dependent suppression of PLB growth. Soon after …

Cancellation Of Cellular Responses To Nanoelectroporation By Reversing The Stimulus Polarity, Andrei G. Pakhomov, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Betsy Gregory, Karl H. Schoenbach

Bioelectrics Publications

Nanoelectroporation of biomembranes is an effect of high-voltage, nanosecond-duration electric pulses (nsEP). It occurs both in the plasma membrane and inside the cell, and nanoporated membranes are distinguished by ion-selective and potential-sensitive permeability. Here we report a novel phenomenon of bioeffects cancellation that puts nsEP cardinally apart from the conventional electroporation and electrostimulation by milli- and microsecond pulses. We compared the effects of 60- and 300-ns monopolar, nearly rectangular nsEP on intracellular Ca²⁺mobilization and cell survival with those of bipolar 60 + 60 and 300 + 300 ns pulses. For diverse endpoints, exposure conditions, pulse numbers (1-60), and …

Calcium-Mediated Pore Expansion And Cell Death Following Nanoelectroporation, Olga N. Pakhomova, Betsy Gregory, Iurii Semenov, Andrei G. Pakhomov

Bioelectrics Publications

Opening of long-lived pores in the cell membrane is the principal primary effect of intense, nanosecond pulsed electric field (nsPEF). Here we demonstrate that the evolution of pores, cell survival, the time and the mode of cell death (necrotic or apoptotic) are determined by the level of external Ca²⁺ after nsPEF. We also introduce a novel, minimally disruptive technique for nsEP exposure of adherent cells on indium tin oxide (ITO)-coated glass coverslips, which does not require cell detachment and enables fast exchanges of bath media. Increasing the Ca²⁺ level from the nominal 2–5 μM to 2 mM for …

Introduction To Fourth Special Issue On Electroporation-Based Technologies And Treatments, Damijan Miklavčič, Lluis M. Mir, P. Thomas Vernier

Bioelectrics Publications

This fourth special electroporation-based technologies and treatments issue of the Journal of Membrane Biology contains reports on recent developments in the field of electroporation by participants in the 7th International Workshop and Postgraduate Course on electroporation based technologies and treatments (EBTT 2013) held in Ljubljana, November 17–23, 2013. The 65 participants included faculty members, invited lecturers, special guests, and young scientists, and students from 16 countries. In addition to lectures on the fundamentals, this year’s sessions included talks on microbial inactivation by pulsed electric fields, modeling of intracellular electroporation, electroporation in food processing, and electrotransfer-facilitated DNA vaccination.

Dielectric Characterization Of Coastal Cartilage Chondrocytes, Michael W. Stacey, Ahmet C. Sabuncu, Ali Beskok

Bioelectrics Publications

BACKGROUND: Chondrocytes respond to biomechanical and bioelectrochemical stimuli by secreting appropriate extracellular matrix proteins that enable the tissue to withstand the large forces it experiences. Although biomechanical aspects of cartilage are well described, little is known of the bioelectrochemical responses. The focus of this study is to identify bioelectrical characteristics of human costal cartilage cells using dielectric spectroscopy.

METHODS: Dielectric spectroscopy allows non-invasive probing of biological cells. An in house computer program is developed to extract dielectric properties of human costal cartilage cells from raw cell suspension impedance data measured by a microfluidic device. The dielectric properties of chondrocytes are …

The Role Of Surface Chemistry In The Toxicity Of Manufactured Cerium Dioxide Nanomaterials To Caenorhabditis Elegans, Emily Kay Oostveen

Theses and Dissertations--Plant and Soil Sciences

Manufactured CeO₂ nanomaterials (CeO₂-MNMs) are used for a wide variety of applications including diesel fuel additives and chemical/mechanical planarization media. To test the effects of CeO₂-MNM surface coating charge on to model organism Caenorhabditis elegans, we synthesized 4 nm CeO₂ with cationic (DEAE-), anionic (CM-), and neutral (DEX) coatings. In L3 nematodes exposed for 24 hours, DEAE-CeO₂ induced lethality at lower concentrations than CM- or DEX-CeO₂. Feeding slightly decreased CeO₂ toxicity, regardless of coating. In L2 nematodes exposed for 48 hours with feeding, DEAE-CeO₂ caused lethality at the …

Helicase-Ssb Interactions In Recombination-Dependent Dna Repair And Replication, Christian Jordan

Graduate College Dissertations and Theses

Dda, one of three helicases encoded by bacteriophage T4, has been well- characterized biochemically but its biological role remains unclear. It is thought to be involved in origin-dependent replication, recombination-dependent replication, anti- recombination, recombination repair, as well as in replication fork progression past template-bound nucleosomes and RNA polymerase. One of the proteins that most strongly interacts with Dda, Gp32, is the only single-stranded DNA binding protein (SSB) encoded by T4, is essential for DNA replication, recombination, and repair.

Previous studies have shown that Gp32 is essential for Dda stimulation of replication fork progression. Our studies show that interactions between Dda …

Molecular Characterization Of Purβ: A Purine-Rich Single-Stranded Dna-Binding Repressor Of Myofibroblast Differentiation, Amy Rumora

Graduate College Dissertations and Theses

The trans-differentiation of injury-activated fibroblasts to myofibroblasts is a process that provides contractile strength for wound closure. Persistent myofibroblast differentiation, however, is associated with fibrotic pathologies such as organ fibrosis, vascular remodeling, and atherosclerotic plaque formation. Myofibroblasts acquire a contractile phenotype with biochemical properties characteristic of both smooth muscle cells and stromal fibroblasts. The cyto-contractile protein, smooth muscle α-actin (SMαA) is a biomarker of myofibroblast differentiation. Expression of the SMαA gene, ACTA2, is regulated by cis-acting elements and transcription factors that activate or repress the ACTA2 promoter.

Purine-rich element binding proteins A (Purα) and B (Purβ) are sequence-specific, …

Regulation Of Β-Casein Gene Expression By Octamer Transcription Factors And Utilization Of Β-Casein Gene Promoter To Produce Recombinant Human Proinsulin In The Transgenic Milk, Xi Qian

Graduate College Dissertations and Theses

β-Casein is a major milk protein, which is synthesized in mammary alveolar secretory epithelial cells (MECs) upon the stimulation of lactogenic hormones, mainly prolactin and glucocorticoids (HP). Previous studies revealed that the proximal promoter (-258 bp to +7 bp) of the β-casein gene is sufficient for induction of the promoter activity by HP. This proximal region contains the binding sites for the signal transducer and activator of transcription 5 (STAT5), glucocorticoid receptor (GR), and octamer transcription factors (Oct). STAT5 and GR are essential downstream mediators of prolactin and glucocorticoid signaling, respectively. This study investigated the functions of Oct-1 and Oct-2 …

Evolution Of A Plant-Specific Copper Chaperone Family For Chloroplast Copper Homeostasis., José Argüello, Crysten Blaby-Haas, Teresita Padilla-Benavides, Roland Stube, Sabeeha Merchant

José M. Argüello

Metallochaperones traffic copper (Cu(+)) from its point of entry at the plasma membrane to its destination. In plants, one destination is the chloroplast, which houses plastocyanin, a Cu-dependent electron transfer protein involved in photosynthesis. We present a previously unidentified Cu(+) chaperone that evolved early in the plant lineage by an alternative-splicing event of the pre-mRNA encoding the chloroplast P-type ATPase in Arabidopsis 1 (PAA1). In several land plants, recent duplication events created a separate chaperone-encoding gene coincident with loss of alternative splicing. The plant-specific Cu(+) chaperone delivers Cu(+) with specificity for PAA1, which is flipped in the envelope relative to …

Insights Into The Cation Permeation Pathway Of Channelrhodopsin-2, Robert Dempski, Ryan Richards

Robert E. Dempski

Channelrhodopsin-2 (ChR2) is a light-activated, non-selective cation channel endogenous to the green algae Chlamydomonas reinhardtii. The unique properties of ChR2 have made it a useful tool in the field of optogenetics. However, the mechanism of ion conductance is not well resolved. Elucidation of the crystal structure of the channelrhodopsin chimera C1C2 has provided structural insight on the putative ChR2 ion conductance pathway. However, it is not clear how the chimeric structure correlates to ChR2 function.

Purification Of An Inducible Dnase From A Thermophilic Fungus, Kyle Landry, Andrea Vu, Robert Levin

Kyle S Landry

Purification And Characterization Of Iso-Ribonucleases From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin

Kyle S Landry

Intrinsic Delocalization During The Decay Of Excitons In Polymeric Solar Cells, Thomas F. George, W. Chen, D. Jiang, R. Chen, S. Li

Thomas George