Biochemistry, Biophysics, and Structural Biology Commons^™

Ultrafast Two-Photon Imaging Of A High-Gain Voltage Indicator In Awake Behaving Mice, Vincent Villette, Mariya Chavarha, Ivan K Dimov, Jonathan Bradley, Lagnajeet Pradhan, Benjamin Mathieu, Stephen W Evans, Simon Chamberland, Dongqing Shi, Renzhi Yang, Benjamin B Kim, Annick Ayon, Abdelali Jalil, François St-Pierre, Mark J Schnitzer, Guoqiang Bi, Katalin Toth, Jun Ding, Stéphane Dieudonné, Michael Z Lin

Faculty, Staff and Students Publications

Optical interrogation of voltage in deep brain locations with cellular resolution would be immensely useful for understanding how neuronal circuits process information. Here, we report ASAP3, a genetically encoded voltage indicator with 51% fluorescence modulation by physiological voltages, submillisecond activation kinetics, and full responsivity under two-photon excitation. We also introduce an ultrafast local volume excitation (ULoVE) method for kilohertz-rate two-photon sampling in vivo with increased stability and sensitivity. Combining a soma-targeted ASAP3 variant and ULoVE, we show single-trial tracking of spikes and subthreshold events for minutes in deep locations, with subcellular resolution and with repeated sampling over days. In the …

Oh Chemistry Of Non-Methane Organic Gases (Nmogs) Emitted From Laboratory And Ambient Biomass Burning Smoke: Evaluating The Influence Of Furans And Oxygenated Aromatics On Ozone And Secondary Nmog Formation, Matthew M. Coggon, Christopher Y. Lim, Abigail R. Koss, Kanako Sekimoto, Bin Yuan, Jessica B. Gilman, David H. Hagan, Vanessa Selimovic, Kyle J. Zarzana, Steven S. Brown, James M Roberts, Markus Müller, Robert Yokelson, Armin Wisthaler, Jordan E. Krechmer, Jose L. Jimenez, Christopher Cappa, Jesse H. Kroll, Joost De Gouw, Carsten Warneke

Chemistry and Biochemistry Faculty Publications

Chamber oxidation experiments conducted at the Fire Sciences Laboratory in 2016 are evaluated to identify important chemical processes contributing to the hydroxy radical (OH) chemistry of biomass burning non-methane organic gases (NMOGs). Based on the decay of primary carbon measured by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS), it is confirmed that furans and oxygenated aromatics are among the NMOGs emitted from western United States fuel types with the highest reactivities towards OH. The oxidation processes and formation of secondary NMOG masses measured by PTR-ToF-MS and iodide-clustering time-of-flight chemical ionization mass spectrometry (I-CIMS) is interpreted using a box model employing …

Characterization Of The Nuclear Pore Complex In Red Alga, Cyanidioschyzon Merolae, Michelle Veronin

Health and Kinesiology Theses

Cyanidioschyzon merolae (C. merolae) is a primitive, unicellular species of red alga that is considered to be one of the simplest self-sustaining eukaryotes. The highly elementary nature of C. merolae makes it an excellent model organism for studying evolution as well as cell function and organelle communication. In our study, we hypothesize that C. merolae contains the minimal assembly of proteins to make up their Nuclear Pore Complexes (NPCs), and hence are the first ancestral NPCs. NPCs are essential for basic nuclear transport in the cell. They are embedded in the double membrane of the nucleus, the …

Total Phenolic And Flavonoid Contents Of Anacyclus Pyrethrum Link Plant Extracts And Their Antioxidant Activity, Hanane Elazzouzi, Nadia Zekri, Touriya Zair, Mohamed Alaoui El Belghiti

Karbala International Journal of Modern Science

In this study, Anacyclus pyrethrm Link (roots) is a medicinal plant from the Asteraceae family, endemic to Morocco and is widely used in traditional medicine; was investigated for their total phenolics, flavonoids contents and antioxidant activities. The quantitative estimation of total flavonoids and phenols by the colorimetric method showed that the extracts were prepared by fractionation of the crude hydromethanolic extract (ethyl acetate and n-butanol). The phenol content of various extracts, estimated by the Folin-Ciocalteu method, was between 1,44 and 12,82 mg EAG / g extract of A. pyrethrum. Moreover, it is clear that ethyl acetate was the …

Structural Basis Of Non-Canonical Transcriptional Regulation By The A-Bound Iron-Sulfur Protein Whib1 In M. Tuberculosis, Tao Wan, Shanren Li, Daisy Guiza Beltran, Andrew Schacht, Lu Zhang, Donald F. Becker, Limei Zhang

Department of Biochemistry: Faculty Publications

WhiB1 is amonomeric iron–sulfur cluster-containing transcription factor in the WhiB-like family that is widely distributed in actinobacteria including the notoriously persistent pathogen Mycobacterium tuberculosis (M. tuberculosis). WhiB1 plays multiple roles in regulating cell growth and responding to nitric oxide stress inM. tuberculosis, but its underlying mechanism is unclear. Here we report a 1.85 A° -resolution crystal structure of the [4Fe–4S] cluster-bound (holo- )WhiB1 in complex with the C-terminal domain of the 70-family primary sigma factor A of M. tuberculosis containing the conserved region 4 (A 4). Region 4 of the 70-family primary sigma factors is commonly used by transcription factors …

Simultaneous Delivery Of Crispr/Cas Complexes And Donor Dna Using Cell-Penetrating Peptide-Adaptors, Maria Mugure Mbugua

Master of Science in Chemical Sciences Theses

Clustered Regularly Interspaced Palindromic Repeats (CRISPR)/CRISPR associated protein (Cas) complexes are becoming the preferred technique for genomic editing because of their precision, efficiency and accuracy. Prokaryotes naturally use CRISPR/Cas complexes to detect and eliminate foreign nucleic acids after infections. Cas proteins form complexes with RNA to cause double-stranded breaks (DSBs) in the invader’s sequence. Researchers are trying to use CRISPR complexes to treat many human diseases caused by these mutations. Research using CRISPR/Cas systems in the treatments of many of the genetic diseases has resulted in misfortunes (such as toxicity to the patient or new diseases) because of the method …

Determination Of Optimal Mild Organic Solvents Of Pdnps For Carbon-Carbon Coupling Reactions, Trina Biswas

Honors College Theses

The synthesis of nanoparticles is an increasingly popular field of interest. The application of nanoparticles is especially popular in the field of nanocatalysts. Metal nanoparticles (NPs) are favorable for catalysis because of the large surface area to volume ratio, which allows them to catalyze a variety of reactions using lesser amounts of active material. As the field of nanoparticle research expands, efforts are being made to create more sustainable approaches to the synthesis of these particles. This research sought to translate the benefits of peptide-based synthesis to organic solvents and use less toxic organic solvents for carbon-carbon coupling reactions, like …

High-Throughput Nano-Scale Characterization Of Membrane Proteins Using Fluorescence-Detection Size-Exclusion Chromatography, Alex J. Vecchio, Robert M. Stroud

Department of Biochemistry: Faculty Publications

Structural biology has revealed predicting heterologous expression levels, homogeneity, and stability of a protein from its primary structure are exceedingly difficult. Membrane proteins, in particular, present numerous challenges that make obtaining milligram quantities of quality samples problematic. For structural and functional investigation of these molecules, however, this is what is required. Fluorescence size-exclusion chromatography (F-SEC), a technique where a protein of biological interest is fused to green fluorescent protein (GFP) and monitored, circumvents many bottlenecks inherent to membrane protein structural biology. In vivo expression yields, as well as in vitro homogeneity and stability, can be rapidly evaluated utilizing nanogram quantities …

Alzheimer's And Amyloid Beta: Amyloidogenicity And Tauopathy Via Dyshomeostatic Interactions Of Amyloid Beta, Jordan Tillinghast

Senior Honors Theses

This paper reviews functions of Amyloid-β (Aβ) in healthy individuals compared to the consequences of aberrant Aβ in Alzheimer’s disease (AD). As extraneuronal Aβ accumulation and plaque formation are characteristics of AD, it is reasonable to infer a pivotal role for Aβ in AD pathogenesis. Establishing progress of the disease as well as the mechanism of neurodegeneration from AD have proven difficult (Selkoe, 1994). This thesis provides evidence suggesting the pathogenesis of AD is due to dysfunctional neuronal processes involving Aβ’s synaptic malfunction, abnormal interaction with tau, and disruption of neuronal homeostasis. Significant evidence demonstrates that AD symptoms are partially …

Differential Analysis Of Individual Centruroides Vittatus Venom

Symposium of Student Scholars

Scorpions are well known, venomous arthropods (Class: Arachnida, Order: Scorpiones). Their venom is composed of neurotoxins, proteases and cytotoxic peptides which plays a major role in toxic components such as inflammatory, antimicrobial and hemolytic activity. Venom is key for the survival of scorpions as it is involved in defense against prey and in feeding on predators. Centruroides vittatus (bark scorpion) is commonly found in North America, with habitat ranges from Nebraska to southern Texas. For this study, scorpions were harvested from Laredo, Texas (27˚57’ N, 99˚43’ W), held in captivity for 4 months and fed a consistent diet of Acheta …

Multidrug Resistance Regulators Mara, Soxs, Rob, And Rama Repress Flagellar Gene Expression And Motility In Salmonella Enterica Serovar Typhimurium, Srinivas Thota, Lon Chubiz

Biology Department Faculty Works

Production of flagella is costly and subject to global multilayered regulation, which is reflected in the hierarchical control of flagellar production in many bacterial species. For Salmonella enterica serovar Typhimurium and its relatives, global regulation of flagellar production primarily occurs through the control of flhDC transcription and mRNA translation. In this study, the roles of the homologous multidrug resistance regulators MarA, SoxS, Rob, and RamA (constituting the mar-sox-rob regulon in S. Typhimurium) in regulating flagellar gene expression were explored. Each of these regulators was found to inhibit flagellar gene expression, production of flagella, and motility. To different degrees, repression via …

Dual Activities Of Plant Cgmp-Dependent Protein Kinase And Its Roles In Gibberellin Signaling And Salt Stress., Qingwen Shen, Xinqiao Zhan, Pei Yang, Jing Li, Jie Chen, Bing Tang, Xuemin Wang, Xuemin Wang, Yueyun Hong

Biology Department Faculty Works

Cyclic GMP (cGMP) is an important regulator in eukaryotes, and cGMP-dependent protein kinase (PKG) plays a key role in perceiving cellular cGMP in diverse physiological processes in animals. However, the molecular identity, property, and function of PKG in plants remain elusive. In this study, we have identified PKG from plants and characterized its role in mediating the gibberellin (GA) response in rice (Oryza sativa). PKGs from plants are structurally unique with an additional type 2C protein phosphatase domain. Rice PKG possesses both protein kinase and phosphatase activities, and cGMP stimulates its kinase activity but inhibits its phosphatase activity. One of …

Comparison Study Of Mold Growth Resistance Of Plastic Based Material Flooring (Pbm Flooring) And Ceramic Tile Flooring, Jyothi Rangineni, Jeremy Tzeng

Publications

Clemson University Department of Biological Sciences and Tile Council of North America Product Performance Testing Laboratory evaluated whether ceramic tile and Plastic Based Material (PBM¹) flooring support mold growth when exposed to fungal spores.

Mold grows in moisture-rich environments and requires only minimal sources of nutrition to support growth. It has long been identified to cause damage to buildings and construction materials and its presence in buildings has been connected to many major health concerns with various studies and reviews published on this matter.²

The method used to evaluate mold growth was ASTM G21-96 (2015).³ This …

Recruitment Of Polycomb-Group Proteins At Giant In Drosophila Embryos, Elnaz Ghotbi Ravandi

Biological Sciences Theses and Dissertations

Polycomb Group (PcG) proteins are evolutionarily conserved epigenetic transcriptional regulators that maintain the transcriptional repression of silenced genes. PcG mediated silencing is divided into two phases: initiation and maintenance. During the initiation phase, PcG proteins initially recognize and bind to their target genes. Once PcG proteins are recruited to their target genes, they can maintain transcriptional repression through an unlimited number of cell cycles. Most studies on PcG proteins have been focused on the maintenance phase of PcG silencing, and the molecular mechanisms by which PcG proteins are initially recruited to their target genes remained unknown. Two models have been …

Characterization Of The Dimerization Domains On The Mannose-6-Phosphate/Insulin-Like Growth Factor Ii Receptor, Tyler Degener

Theses/Capstones/Creative Projects

The mannose-6-phosphate/insulin-like growth factor II (M6P/IGF2) receptor is a transmembrane protein known to sequester growth factors from the extracellular matrix. This behavior suggests a mechanism of tumor suppression. Structurally, the receptor’s extracellular region is segmented into 15 homologous repeats, which are divided further into 5 triplet domains, labelled 1-3, 4-6, 7-9, 10-12, and 13-15. What is notable about the triplets is their propensity to form dimers with triplets on a second M6P/IGF2 receptor. In fact, previous studies indicate that this protein functions optimally when dimerized. Thus, the purpose of this experiment is to characterize these domain interactions. Using a urea …

Investigation Of Phosphoserine Aminotransferase 1(Psat1) In Breast Cancer Progression., Stephanie Metcalf

Electronic Theses and Dissertations

This dissertation describes my research into the involvement of phosphoserine aminotransferase 1 (PSAT1) in breast cancer progression; specifically, in triple negative breast cancer (TNBC) metastasis and endocrine resistance in estrogen receptor positive breast cancer (ER+BC). Breast cancer is the most common tumor diagnosis among women. While the overall 5-year survival for breast cancer is reaching 90%, the 5-year survival for metastatic disease is only 22%. Metastasis and endocrine resistance combined can affect over 50% of patients. One of the proteins and pathways implicated in both metastasis and endocrine resistance in breast cancer is phosphoserine aminotransferase 1 (PSAT1) and the serine …

Effects Of The Dihydrouracil Lesion On Dna Using 1h/31p 1d And 2d Solution Nmr, Benjamin M. Boyd

Graduate Theses/Dissertations

The effects of the dihydrouracil lesion in DNA were studied using two dimensional NMR spectroscopy. The sequence used was based off of the Drew-Dickerson Dodecamer, with the cytosine in the three position replaced by a dihydrouracil. All of the nonexchangeable proton chemical shifts, with the exception of the H2, H5’, and H5’’, of the lesioned DNA were identified using NOESY spectra and then compared to the chemical shift values of the Drew Dickerson Dodecamer. The largest differences in chemical shifts were observed in the nucleotides neighboring the lesion, both within the strand and on the opposite strand. The imino exchangeable …

Electropermeabilization Does Not Correlate With Plasma Membrane Lipid Oxidation, Olga Michel, Andrei G. Pakhomov, Maura Casciola, Jolanta Saczko, Julita Kulbacka, Olga N. Pakhomova

Bioelectrics Publications

The permeabilized condition of the cell membrane after electroporation can last minutes but the underlying mechanisms remain elusive. Previous studies suggest that lipid peroxidation could be responsible for the lasting leaky state of the membrane. The present study aims to link oxidation within the plasma membrane of live cells to permeabilization by electric pulses. We have introduced a method for the detection of oxidation by ratiometric fluorescence measurements of BODIPY-C11 dye using total internal reflection fluorescence (TIRF) microscopy, limiting the signal to the cell membrane. CHO-K1 cells were cultured on glass coverslips coated with an electroconductive indium tin oxide (ITO) …

Rotational Tuning Of Transmembrane Helix Properties Based On The Precise Placements Of Aromatic And Charged Residues, Matthew J. Mckay

Graduate Theses and Dissertations

Designed model transmembrane peptides and oriented 2H and 15N solid-state nuclear magnetic resonance (NMR) spectroscopy were used to analyze how simple sequence modifications can influence peptide structure, behavior and dynamics as well as for determining the pKa of glutamic acid at the membrane interface. The GW5,19ALP23 (acetyl-GGALW(LA)6LWLAGA-amide) peptide framework adopts a well-defined tilted orientation in lipid bilayers (DLPC, DMPC and DOPC) and undergoes low amounts of dynamic motion. The sequence was initially modified by moving the Trp residues outwards to positions 4 and 20. This new sequence GW4,20ALP23 (acetyl-GGAW(AL)7AWAGA-amide) displays high amounts of signal averaging of NMR observables caused by …

Influence Of Single And Multiple Histidine Residues And Their Ionization Properties On Transmembrane Helix Dynamics, Orientations And Fraying, Fahmida Afrose

Graduate Theses and Dissertations

Since aromatic and charged residues are often present in various locations of transmembrane helices of integral membrane proteins, their impacts on the molecular properties of transmembrane proteins and their interactions with lipids are of particular interest in many studies. In this work, I used solid-state deuterium NMR spectroscopy in designed model peptide GWALP23 [GGALW(LA)6LWLAGA] with selective deuterium labels to addresses the pH dependence and influence of single and multiple “guest” histidine residues in the orientation and dynamic behaviors of transmembrane proteins. The mutations include Gly to His (G2/22 to H2/22), Trp to His (W5/19 to H5/19) and Leu to His …