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Articles 1 - 30 of 88

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Damped Oscillating Phosphoryl Transfer Reaction In The Cyanobacterial Circadian Clock, Hye In Jang, Pyonghwa Kim, Yongick Kim Mar 2023

Damped Oscillating Phosphoryl Transfer Reaction In The Cyanobacterial Circadian Clock, Hye In Jang, Pyonghwa Kim, Yongick Kim

Chemistry Faculty Research

Most organisms have circadian clocks to ensure the metabolic cycle to resonate with the rhythmic environmental changes without “damping,” or losing robustness. Cyanobacteria is the oldest and simplest form of life that is known to harbor this biological intricacy. Its KaiABC-based central oscillator proteins can be reconstituted inside a test tube, and the post-translational modification cycle occurs with 24 h periodicity. KaiC’s two major phosphorylation sites, Ser-431 and Thr-432, become phosphorylated and dephosphorylated by interacting with KaiA and KaiB, respectively. Here, we mutate Thr-432 into Ser to find the oscillatory phosphoryl transfer reaction damps. Previously, this mutant KaiC was reported …


Spatially Controlled Monolayers For Electrically Switchable Biomolecule Detection, Eduard Lukhmanov Jan 2022

Spatially Controlled Monolayers For Electrically Switchable Biomolecule Detection, Eduard Lukhmanov

Theses, Dissertations and Capstones

The development of biosensors that are low-waste, highly stable, and possess an ability to be interchanged between capturing and non-capturing configurations is promising for the biodetector field. Stable packing and attachment of the sensor, the ability to create an interchangeable detecting probe of interest relatively easily, and dynamic control of the probe via a reversible bias can provide for that. With the set goals to control all those properties, DNA-dendron conjugate molecules were designed, synthesized in solution, purified, and utilized to make self-assembled monolayers of single-stranded DNA on gold. To be able to manipulate the conjugates’ sensing qualities in the …


Examining The Effects Of Exercise-Induced, Physical Stress Overtraining On Stress Biomarkers In Adolescent, C57bl/6 Mice, Curtis Scotty Davis Jan 2022

Examining The Effects Of Exercise-Induced, Physical Stress Overtraining On Stress Biomarkers In Adolescent, C57bl/6 Mice, Curtis Scotty Davis

Theses, Dissertations and Capstones

Exercise has long been established as a therapeutic modality to improve health and related physical fitness, sports performance, and injury/risk reduction in both adults and adolescents (Haff & Triplett, 2015; Kaminsky, 2010). Nonetheless, there is a lack of research investigating the negative effects of exercise overstress (i.e., overtraining syndrome) in these populations, particularly adolescents (Brenner & American Academy of Pediatrics Council on Sports Medicine and Fitness, 2007; Matos & Winsley, 2007). The objective of this study was to examine hormone biochemical markers, anthropometric markers, and behavioral traits, which are associated with overtraining syndrome, in adolescent C57BL/6 mice. A total of …


Shift In Conformational Equilibrium Underlies The Oscillatory Phosphoryl Transfer Reaction In The Circadian Clock, Pyonghwa Kim, Neha Thati, Shreya Peshori, Hye-In Jang, Yongick Kim Oct 2021

Shift In Conformational Equilibrium Underlies The Oscillatory Phosphoryl Transfer Reaction In The Circadian Clock, Pyonghwa Kim, Neha Thati, Shreya Peshori, Hye-In Jang, Yongick Kim

Chemistry Faculty Research

Oscillatory phosphorylation/dephosphorylation can be commonly found in a biological system as a means of signal transduction though its pivotal presence in the workings of circadian clocks has drawn significant interest: for example in a significant portion of the physiology of Synechococcus elongatus PCC 7942. The biological oscillatory reaction in the cyanobacterial circadian clock can be visualized through its reconstitution in a test tube by mixing three proteins—KaiA, KaiB and KaiC—with adenosine triphosphate and magnesium ions. Surprisingly, the oscillatory phosphorylation/dephosphorylation of the hexameric KaiC takes place spontaneously and almost indefinitely in a test tube as long as ATP is present. This …


Potential Counter Regulatory Effects Of A Gut Microbiota Metabolite In Alleviating Down-Regulation Krüppel-Like Factor 4 In Intestinal Inflammation, Ylva Forslund Jan 2021

Potential Counter Regulatory Effects Of A Gut Microbiota Metabolite In Alleviating Down-Regulation Krüppel-Like Factor 4 In Intestinal Inflammation, Ylva Forslund

Theses, Dissertations and Capstones

Inflammatory bowel disease (IBD) is a medical condition characterized by chronic inflammation of the intestinal epithelium. Krüppel-like factor 4 (KLF4), a zinc finger transcription factor, is vital for maintaining intestinal epithelial homeostasis. KLF4 promotes differentiation of goblet cells that generate the protective mucus layer. Reduced goblet cell number and defective mucus layer are associated with IBD. Shortchain fatty acids (SCFA) are known to play an important role in the maintenance of a strong and healthy intestinal epithelial layer and also in goblet cell differentiation. However, whether the positive effects of SCFAs on goblet cells are mediated, at least partly, via …


The Effects Of Endocrine Disrupting Chemicals On Plants, Christian Mathew Pridemore Jan 2021

The Effects Of Endocrine Disrupting Chemicals On Plants, Christian Mathew Pridemore

Theses, Dissertations and Capstones

Endocrine disrupting chemicals (EDCs) are a diverse group of chemicals which can have a detrimental effect on human health, affecting any physiological body system sensitive to hormonal changes. Human exposure to EDCs is inevitable due to their prevalence in modern living; EDCs are integral compounds found in everyday items with which humans interact and ingest. These, along with other indirect avenues leading to EDC exposure, pose a threat to both human health and to the health of wildlife and agricultural environments. Studies on the effects of EDCs on plants can be substantially informative and necessary for progress towards solving the …


The Circadian Clock—A Molecular Tool For Survival In Cyanobacteria, Pyonghwa Kim, Manpreet Kaur, Hye-In Jang, Yongick Kim Dec 2020

The Circadian Clock—A Molecular Tool For Survival In Cyanobacteria, Pyonghwa Kim, Manpreet Kaur, Hye-In Jang, Yongick Kim

Chemistry Faculty Research

Cyanobacteria are photosynthetic organisms that are known to be responsible for oxygenating Earth’s early atmosphere. Having evolved to ensure optimal survival in the periodic light/dark cycle on this planet, their genetic codes are packed with various tools, including a sophisticated biological timekeeping system. Among the cyanobacteria is Synechococcus elongatus PCC 7942, the simplest clock-harboring organism with a powerful genetic tool that enabled the identification of its intricate timekeeping mechanism. The three central oscillator proteins—KaiA, KaiB, and KaiC—drive the 24 h cyclic gene expression rhythm of cyanobacteria, and the “ticking” of the oscillator can be reconstituted inside a test tube just …


Identifying C-Mannosylatedproteins In Raw264.7 Cells Via In Vitro Hsc70 Co-Immunoprecipitation Strategies, Nicholas Ryan Kegley Jan 2019

Identifying C-Mannosylatedproteins In Raw264.7 Cells Via In Vitro Hsc70 Co-Immunoprecipitation Strategies, Nicholas Ryan Kegley

Theses, Dissertations and Capstones

C-mannosylation is a specific type of glycosylation in which α-mannose is covalently bound to the C2 atom of a tryptophan via a carbon-carbon bond. Presently, it is known to occur on proteins that contain the W-x-x-W-x-x-W/C motif found within the Thrombospondin Type-1 Repeat (TSR), with ‘x’ denoting any amino acid. C-mannosylation has been implicated in a number of cellular functions, including protein secretion and type I cytokine receptor function. Previous research has shown that exogenous C-mannosylated peptides derived from TSR-containing proteins upregulate the production of the pro-inflammatory cytokine Tumor Necrosis Factor alpha (TNF-α) in RAW264.7 macrophage cells. This upregulation is …


Characterizing The Effects Of Environmental Stressors On The Photosynthetic Capacity Of Chlorella Vulgaris, Amanda Louise Smythers Jan 2019

Characterizing The Effects Of Environmental Stressors On The Photosynthetic Capacity Of Chlorella Vulgaris, Amanda Louise Smythers

Theses, Dissertations and Capstones

Chlorella vulgaris is a unicellular green algae grown throughout the world. Due to its multiple trophic modes as well as its ability to maintain high rates of growth under adverse conditions, it has been of global interest for use in ecological contamination studies, biofuel feedstock optimization, and studies of photosynthetic electron transfer. Using a wide-range of methods for physiological and photosynthetic characterization, the studies within seek to further extend the usefulness of C. vulgaris in a variety of environmentally important studies. Once the protocols were optimized specifically for this alga, they could be applied in both ecologically relevant and biodiesel …


Isolation And Identification Of Hsc70 Conjugates In Raw264.7 Murine Macrophage-Like Cells, Michael Arland Parsons Jan 2019

Isolation And Identification Of Hsc70 Conjugates In Raw264.7 Murine Macrophage-Like Cells, Michael Arland Parsons

Theses, Dissertations and Capstones

IL12R- β2 is a Type I cytokine receptor and contains the WXXW (WSNWS) sequence that often predicates the post-translational addition of mannose to a tryptophan residue via a carbon-carbon bond. This study will stimulate expression of IL12R- β2 in RAW 264.7 Macrophage-Like Cells by shutting down the extracellular signal kinase (ERK) pathway and introducing inflammatory agents lipopolysaccharide and CpG DNA in order to collect a concentrated sample of IL12R- β2. These samples will be analyzed for the presence of C-mannosyltryptophan residue


Heterologous Expression Of Secreted Bacterial Bpp And Hap Phytases In Plants Stimulates Arabidopsis Thaliana Growth On Phytate., Lia R. Valeeva, Chuluuntsetseg Nyamsuren, Margarita R. Sharipova, Eugene V. Shakirov Feb 2018

Heterologous Expression Of Secreted Bacterial Bpp And Hap Phytases In Plants Stimulates Arabidopsis Thaliana Growth On Phytate., Lia R. Valeeva, Chuluuntsetseg Nyamsuren, Margarita R. Sharipova, Eugene V. Shakirov

Biological Sciences Faculty Research

Phytases are specialized phosphatases capable of releasing inorganic phosphate from myo-inositol hexakisphosphate (phytate), which is highly abundant in many soils. As inorganic phosphorus reserves decrease over time in many agricultural soils, genetic manipulation of plants to enable secretion of potent phytases into the rhizosphere has been proposed as a promising approach to improve plant phosphorus nutrition. Several families of biotechnologically important phytases have been discovered and characterized, but little data are available on which phytase families can offer the most benefits toward improving plant phosphorus intake. We have developed transgenic Arabidopsis thaliana plants expressing bacterial phytases PaPhyC (HAP family …


The Role Of Oxidation-Sensitive Nociception And Epigenetics In Endometriosis-Associated Pain, Kristeena Ray Wright Jan 2017

The Role Of Oxidation-Sensitive Nociception And Epigenetics In Endometriosis-Associated Pain, Kristeena Ray Wright

Theses, Dissertations and Capstones

Endometriosis is an enigmatic disease that is associated with severe symptoms and consequences such as total hysterectomy. Upwards of 10% of women of reproductive age have endometriosis, most of whom are afflicted with chronic pelvic pain and/or infertility. Despite many treatment options available to endometriosis patients, there is no cure for this condition and recurrence of symptoms is extremely common. In CHAPTER 1, we describe the mechanisms involved in endometriotic pain and the currently available treatment strategies. Our laboratory has provided evidence for the role of oxidative stress in the etiology of endometriosis and its associated pain. In this dissertation …


Microbial Phytases And Phytate: Exploring Opportunities For Sustainable Phosphorus Management In Agriculture, Nelly P. Balaban, Aliya D. Suleimanova, Lia R. Valeeva, Inna B. Chastukhina, Natalia L. Rudakova, Margarita R. Sharipova, Eugene V. Shakirov Dec 2016

Microbial Phytases And Phytate: Exploring Opportunities For Sustainable Phosphorus Management In Agriculture, Nelly P. Balaban, Aliya D. Suleimanova, Lia R. Valeeva, Inna B. Chastukhina, Natalia L. Rudakova, Margarita R. Sharipova, Eugene V. Shakirov

Biological Sciences Faculty Research

Myo-inositol phosphates (phytates) are important biological molecules produced largely by plants to store phosphorus. Phytate is very abundant in many different soils making up a large portion of all soil phosphorus. This review assesses current phytase science from the perspective of its substrate, phytate, by examining the intricate relationship between the phytate-hydrolyzing enzymes and phytate as their substrate. Specifically, we examine available data on phytate’s structural features, distribution in nature and functional roles. The role of phytases and their localization in soil and plant tissues are evaluated. We provide a summary of the current biotechnological advances in using industrial …


Promises And Challenges Of Eco-Physiological Genomics In The Field: Tests Of Drought Responses In Switchgrass. Plant Physiology, John T. Lovell, Eugene V. Shakirov, Scott Schwartz, David B. Lowry, Michael J. Aspinwall, Samuel H. Taylor, Jason Bonnette, Juan Diego Palacio-Mejia, Christine V. Hawkes, Philip A. Fay, Thomas E. Juenger Oct 2016

Promises And Challenges Of Eco-Physiological Genomics In The Field: Tests Of Drought Responses In Switchgrass. Plant Physiology, John T. Lovell, Eugene V. Shakirov, Scott Schwartz, David B. Lowry, Michael J. Aspinwall, Samuel H. Taylor, Jason Bonnette, Juan Diego Palacio-Mejia, Christine V. Hawkes, Philip A. Fay, Thomas E. Juenger

Biological Sciences Faculty Research

Identifying the physiological and genetic basis of stress tolerance in plants has proven to be critical to understanding adaptation in both agricultural and natural systems. However, many discoveries were initially made in the controlled conditions of greenhouses or laboratories, not in the field. To test the comparability of drought responses across field and greenhouse environments, we undertook three independent experiments using the switchgrass reference genotype Alamo AP13. We analyzed physiological and gene expression variation across four locations, two sampling times, and three years. Relatively similar physiological responses and expression coefficients of variation across experiments masked highly dissimilar gene expression responses …


Heterologous Expression Of Pantoea Agglomerans Phytase Gene Optimized For Plant-Host Expression, N. N. Khabipova, L. R. Valeeva, I. B. Chastukhina, M. R. Sharipova, Eugene V. Shakirov Jun 2016

Heterologous Expression Of Pantoea Agglomerans Phytase Gene Optimized For Plant-Host Expression, N. N. Khabipova, L. R. Valeeva, I. B. Chastukhina, M. R. Sharipova, Eugene V. Shakirov

Biological Sciences Faculty Research

Here we report expression and characterization of recombinant bacterial phytase PaPhyC from Pantoea sp. Codon-optimized phytase gene was expressed E.coli BL21 pLysS and protein expression was confirmed by Western blotting. Recombinant protein expressed in E.coli has high phytase activity. We show that PaPhyC recombinant phytase has different molecular masses when expressed in bacteria and plants, suggesting that possible protein glycosylation in plants may influence its overall size.


Drought Responsive Gene Expression Regulatory Divergence Between Upland And Lowland Ecotypes Of A Perennial C4 Grass, John T. Lovell, Scott Schwartz, David B. Lowry, Eugene V. Shakirov, Jason E. Bonnette, Xiaoyu Weng, Mei Wang, Jenifer Johnson, Avinash Sreedasyam, Christopher Plott, Jerry Jenkins, Jeremy Schmutz, Thomas E. Juenger Mar 2016

Drought Responsive Gene Expression Regulatory Divergence Between Upland And Lowland Ecotypes Of A Perennial C4 Grass, John T. Lovell, Scott Schwartz, David B. Lowry, Eugene V. Shakirov, Jason E. Bonnette, Xiaoyu Weng, Mei Wang, Jenifer Johnson, Avinash Sreedasyam, Christopher Plott, Jerry Jenkins, Jeremy Schmutz, Thomas E. Juenger

Biological Sciences Faculty Research

Climatic adaptation is an example of a genotype-by-environment interaction (G×E) of fitness. Selection upon gene expression regulatory variation can contribute to adaptive phenotypic diversity; however, surprisingly few studies have examined how genome-wide patterns of gene expression G×E are manifested in response to environmental stress and other selective agents that cause climatic adaptation. Here, we characterize drought-responsive expression divergence between upland (drought-adapted) and lowland (mesic) ecotypes of the perennial C4 grass, Panicum hallii, in natural field conditions. Overall, we find that cis-regulatory elements contributed to gene expression divergence across 47% of genes, 7.2% of which exhibit drought-responsive G×E. …


An Investigation Of The Effect Of Mn2+ On The Fth1 Ire-Irp Complex, Eric Thomas Mendenhall Jan 2015

An Investigation Of The Effect Of Mn2+ On The Fth1 Ire-Irp Complex, Eric Thomas Mendenhall

Theses, Dissertations and Capstones

Iron is a widely distributed metal found in almost every physiological system in nature, thus being an essential part of life. Iron homeostasis in the human body must be tightly regulated as iron is both beneficial and harmful to different cellular processes. Ferritin is a protein that has a prominent role in maintaining iron homeostasis via iron sequestration. Additionally, this protein itself is regulated by the Iron Responsive Element (IRE) and its interaction with an apoaconitase protein or the Iron Regulatory Protein (IRP). The binding of the IRP to this IRE, located on the 5’ untranslated stem loop region of …


Epigenetic Role Of Ptip In Mouse Spermatogenesis, Chengjing Liu Jan 2015

Epigenetic Role Of Ptip In Mouse Spermatogenesis, Chengjing Liu

Theses, Dissertations and Capstones

In mammals, spermatogenesis is a biological process inside the testis to produce spermatozoa from spermatogonia. This process is governed by both genetic and epigenetic mechanisms and thus is a powerful system for epigenetic research. Methylation of histone 3 lysine 4 (H3K4) is an epigenetic mark, which has been found to be dynamically modulated in mouse male germ cells during spermatogenesis. Pax2 Transactivation domain Interaction Protein (PTIP) has been recently identified as part of a H3K4 methyltransferase complex. In this study, I hypothesize that PTIP is an essential epigenetic regulator in mouse spermatogenesis. To test this hypothesis, I first established a …


Glycation Of Lysozyme, Wisam Talib Joudah Jan 2015

Glycation Of Lysozyme, Wisam Talib Joudah

Theses, Dissertations and Capstones

For this research project, I propose a method for the analysis of glycated lysozyme using Matrix Associated Laser Desorption / Ionization-Time of Flight Mass spectrometry (MALDI-TOF MS). Glycation or "Maillard reaction" is a non-enzymatic reaction that occurs between amino acid residues, usually primary and secondary amines, of proteins and the carbonyl group of reducing sugars to yield Schiff bases. The glycation mechanism occurs between the carbonyl group of the reducing sugars and a primary amine by nucleophilic addition, resulting in the formation of a Schiff base. The Schiff base can then rearrange into the more stable Amadori product which is …


Investigation Into The Biological Importance And Function Of Proinsulin C-Peptide, Christina L. Newsome Jan 2015

Investigation Into The Biological Importance And Function Of Proinsulin C-Peptide, Christina L. Newsome

Theses, Dissertations and Capstones

The C-peptide of insulin was thought to be biologically inactive, but recent studies have shown that the C-peptide causes multiple molecular and physiological effects. Evidence has shown that C-peptide binds to a cell surface receptor, probably a G-protein coupled receptor, and that the COOH-terminal pentapeptide is essential for binding and constitutes an active site. For a further understanding of the detailed nature of the physiological effects of C-peptide, the receptor structure needs to be determined. We designed an affinity column using C-peptide to try and gain a better understanding of the biological effects by examining what proteins the affinity column …


Investigation Into The Cellular Actions Of Carnosine And C-Peptide, Emma H. Gardner Jan 2014

Investigation Into The Cellular Actions Of Carnosine And C-Peptide, Emma H. Gardner

Theses, Dissertations and Capstones

Carnosine is a dipeptide composed of beta-alanine and histidine found exclusively in long-lived animal tissues. The cellular action of carnosine is still under extensive investigation; however, it has been proposed to have a role as an anti-oxidant and oxygen free radical scavenger, a physiological buffer, a heavy metal chelator, and has been implicated as an anti-aging agent.2,4 Our lab has been studying the interaction between carnosine and heme by analyzing both the effect carnosine has on the glycation of the heme containing protein cytochrome c and the interaction of carnosine with free hemin. We have observed that the addition …


Involvement Of Reactive Oxygen Species In A Feed-Forward Mechanism Of Na/K-Atpase Mediated Signaling, Yanling Yan, Anna P. Shapiro, Steven Haller, Vinal Katragadda, Lijun Liu, Jiang Tian, Venkatesha Basrur, Deepak Malhotra, Zi-Jian Xie, Nader G. Abraham, Joseph I. Shapiro Md, Jiang Liu Oct 2013

Involvement Of Reactive Oxygen Species In A Feed-Forward Mechanism Of Na/K-Atpase Mediated Signaling, Yanling Yan, Anna P. Shapiro, Steven Haller, Vinal Katragadda, Lijun Liu, Jiang Tian, Venkatesha Basrur, Deepak Malhotra, Zi-Jian Xie, Nader G. Abraham, Joseph I. Shapiro Md, Jiang Liu

Biochemistry and Microbiology

Cardiotonic steroids (such as ouabain) signaling through Na/K-ATPase regulate sodium reabsorption in the renal proximal tubule. We report here that reactive oxygen species are required to initiate ouabain-stimulated Na/K-ATPase·c-Src signaling. Pretreatment with the antioxidant N-acetyl-L-cysteine prevented ouabain-stimulated Na/K-ATPase·c-Src signaling, protein carbonylation, redistribution of Na/K-ATPase and sodium/proton exchanger isoform 3, and inhibition of active transepithelial 22Na+ transport. Disruption of the Na/K-ATPase·c-Src signaling complex attenuated ouabain-stimulated protein carbonylation. Ouabain-stimulated protein carbonylation is reversed after removal of ouabain, and this reversibility is largely independent of de novo protein synthesis and degradation by either the lysosome or the proteasome pathways. Furthermore, …


Draft Genome Sequence Of A Stable Mucoid Strain Of Pseudomonas Aeruginosa Pao581 With A Muca25 Mutation, Yeshi Yin, T. Ryan Withers, John R. W. Govan, Shannon L. Johnson, Hongwei D. Yu Sep 2013

Draft Genome Sequence Of A Stable Mucoid Strain Of Pseudomonas Aeruginosa Pao581 With A Muca25 Mutation, Yeshi Yin, T. Ryan Withers, John R. W. Govan, Shannon L. Johnson, Hongwei D. Yu

Biochemistry and Microbiology

A mutation in the mucA gene, which encodes a negative regulator of alginate production in Pseudomonas aeruginosa, is the main mechanism underlying the conversion to mucoidy in clinical isolates from patients with cystic fibrosis (CF). Here, we announce the draft genome sequence of the stable alginate-overproducing mucoid strain P. aeruginosa PAO581 with a mucA25 mutation, a derivative from the nonmucoid strains P. aeruginosa PAO381 and PAO1.


Draft Genome Sequence Of A Mucoid Isolate Of Pseudomonas Aeruginosa Strain C7447m From A Patient With Cystic Fibrosis, Yeshi Yin, T. Ryan Withers, Shannon L. Johnson, Hongwei D. Yu Sep 2013

Draft Genome Sequence Of A Mucoid Isolate Of Pseudomonas Aeruginosa Strain C7447m From A Patient With Cystic Fibrosis, Yeshi Yin, T. Ryan Withers, Shannon L. Johnson, Hongwei D. Yu

Biochemistry and Microbiology

Alginate overproduction by Pseudomonas aeruginosa, or mucoidy, plays an important role in the pathogenesis of chronic lung infections in cystic fibrosis (CF) patients. Here we report the draft genome sequence of a clinical isolate of mucoid P. aeruginosa strain C7447m from a CF patient with chronic lung infection.


Evidence For Sigma Factor Competition In The Regulation Of Alginate Production By Pseudomonas Aeruginosa, Yeshi Yin, T. Ryan Withers, Xin Wang, Hongwei D. Yu Aug 2013

Evidence For Sigma Factor Competition In The Regulation Of Alginate Production By Pseudomonas Aeruginosa, Yeshi Yin, T. Ryan Withers, Xin Wang, Hongwei D. Yu

Biochemistry and Microbiology

Alginate overproduction, or mucoidy, plays an important role in the pathogenesis of P. aeruginosa lung infection in cystic fibrosis (CF). Mucoid strains with mucA mutations predominantly populate in chronically-infected patients. However, the mucoid strains can revert to nonmucoidy in vitro through suppressor mutations. We screened a mariner transposon library using CF149, a non-mucoid clinical isolate with a misssense mutation in algU(AlgUA61V). The wild type AlgU is a stress-related sigma factor that activates transcription of alginate biosynthesis. Three mucoid mutants were identified with transposon insertions that caused 1) an overexpression of AlgUA61V, 2) an overexpression of …


Truncation Of Type Iv Pilin Induces Mucoidy In Pseudomonas Aeruginosa Strain Pao579, T. Ryan Withers, F. Heath Damron, Yeshi Yin, Hongwei D. Yu Jun 2013

Truncation Of Type Iv Pilin Induces Mucoidy In Pseudomonas Aeruginosa Strain Pao579, T. Ryan Withers, F. Heath Damron, Yeshi Yin, Hongwei D. Yu

Biochemistry and Microbiology

Pseudomonas aeruginosa is a Gram negative, opportunistic pathogen that uses the overproduction of alginate, a surface polysaccharide, to form biofilms in vivo. Overproduction of alginate, also known as mucoidy, affords the bacterium protection from the host's defenses and facilitates the establishment of chronic lung infections in individuals with cystic fibrosis. Expression of the alginate biosynthetic operon is primarily controlled by the alternative sigma factor AlgU (AlgT/σ22). In a nonmucoid strain, AlgU is sequestered by the transmembrane antisigma factor MucA to the cytoplasmic membrane. AlgU can be released from MucA via regulated intramembrane proteolysis by proteases AlgW and MucP …


Cyclooxygenase-2 Dependent Metabolism Of 20-Hete Increases Adiposity And Adipocyte Enlargement In Mesenchymal Stem Cell-Derived Adipocytes, Dong Hyun Kim, Nitin Puri, Komal Sodhi, John R. Falck, Nader G. Abraham, Joseph I. Shapiro M.D., Michal L. Schwartzman Jan 2013

Cyclooxygenase-2 Dependent Metabolism Of 20-Hete Increases Adiposity And Adipocyte Enlargement In Mesenchymal Stem Cell-Derived Adipocytes, Dong Hyun Kim, Nitin Puri, Komal Sodhi, John R. Falck, Nader G. Abraham, Joseph I. Shapiro M.D., Michal L. Schwartzman

Biochemistry and Microbiology

Abstract 20-Hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE), a product of the cytochrome P450 (CYP)-catalyzed [1] -hydroxylation of arachidonic acid, induces oxidative stress and, in clinical studies, is associated with increased body mass index (BMI) and the metabolic syndrome. This study was designed to examine the effects of exogenous 20- HETE on mesenchymal stem cell (MSC)-derived adipocytes.

The expression levels of CYP4A11 and CYP4F2 (major 20-HETE synthases in humans) in MSCs decreased during adipocyte differentiation; however, exogenous administration of 20-HETE (0.1–1 M) increased adipogenesis in a dose dependent manner in these cells ( P < 0.05). The inability of a 20-HETE analog to reproduce these effects suggested the involvement of a metabolic product of 20-HETE in mediating its pro-adipogenic effects. A cyclooxygenase (COX)-1 selective inhibitor enhanced, whereas a COX-2 selective or a dual COX-1/2 inhibitor attenuated adipogenesis induced by 20-HETE. The COX-derived metabolite of 20-HETE, 20-OH-PGE 2 , enhanced adipogenesis and lipid accumulation in MSCs. The pro-adipogenic effects of 20-HETE and 20-OH-PGE 2 resulted in the increased expression of the adipogenic regulators PPAR and -catenin in MSC-derived adipocytes. Taken together we show for the fi rst time that 20-HETE-derived COX-2-dependent 20-OH-PGE 2 enhances mature infl amed adipocyte hypertrophy in MSC undergoing adipogenic differentiation. — Kim, D. H., N. Puri, K. Sodhi, J. R. Falck, N. G. Abraham, J. Shapiro, and M. L. Schwartzman. Cyclooxygenase-2 dependent metabolism of 20-HETE increasesadiposity and adipocyte enlargement in mesenchymal stem cell-derived adipocytes.


Genetic Regulation Of Mucoidy In Pseudomonas Aeruginosa, T. Ryan Withers Jan 2013

Genetic Regulation Of Mucoidy In Pseudomonas Aeruginosa, T. Ryan Withers

Theses, Dissertations and Capstones

Cystic fibrosis is a genetic disorder that results from mutations in the CF transmembrane conductance regulator gene. These mutations cause a disruption in the chloride transport in mucosal tissues causing the accumulation of dehydrated mucus, and a decrease in the mucocilliary removal of environmental pathogens within the lungs. Additionally, the accumulation of dehydrated mucus within the lungs provides a hospitable environment for various bacteria, including the Gram-negative opportunistic pathogen Pseudomonas aeruginosa. P. aeruginosa uses the overproduction of a surface polysaccharide called alginate to form a biofilm to evade the host’s immunological defenses. The overproduction of alginate, often referred to as …


Toward A Comprehensive Model Of Photosystem Ii Oxygen Evolving Complex Photoassembly, James Scott Board Ii Jan 2013

Toward A Comprehensive Model Of Photosystem Ii Oxygen Evolving Complex Photoassembly, James Scott Board Ii

Theses, Dissertations and Capstones

Elucidating the mechanism of photoassembly of the oxygen-evolving complex (OEC) will lead to a better understanding of how nature catalyzes water oxidation. Although the temperature dependence of oxygen evolution has been described in the literature [1,2], we have performed a comprehensive study that covers Photosystem II (PSII) activity oxygen evolution in the presence and absence of 2,6-dichloro-1,4benzoquinone (DCBQ) from 5–45°C. In addition, we performed similar measurements for OEC photoassembly in the absence of DCBQ. PSIIenriched particles used for our measurements were prepared according to Berthold, Babcock, and Yocum[3], with modifications from Kolling, et al.[4] The oxygen-evolution of intact BBY particles …


Omega-3 Fatty Acids As Therapeutic Options For The Treatment Of B-Cell Chronic Lymphocytic Leukemia, Johannes Francois Fahrmann Jan 2013

Omega-3 Fatty Acids As Therapeutic Options For The Treatment Of B-Cell Chronic Lymphocytic Leukemia, Johannes Francois Fahrmann

Theses, Dissertations and Capstones

B-cell chronic lymphocytic leukemia (CLL) is the most common form of adult leukemia in the western world. CLL is often diagnosed in the asymptomatic (early-stage) stages. However, approximately 50% of these patients will progress to advanced, symptomatic disease and require therapy. Current treatment options are limited due to progressive drug resistance and severe drug-induced toxicities which are often too toxic for the elderly or those with co-morbidities. Therefore, a non-toxic therapeutic intervention that could slow the progression of asymptomatic CLL to symptomatic CLL or enhance the effects of actively used chemo-therapeutic drugs in patients who require therapy would be clinically …