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Articles 1 - 22 of 22
Full-Text Articles in Medical Genetics
The Presence Of Childhood Obesity In Nebraska And The Physiological Repercussions Of The Disease, Madison R. Bezousek
The Presence Of Childhood Obesity In Nebraska And The Physiological Repercussions Of The Disease, Madison R. Bezousek
Honors Theses
Childhood Obesity can cause lifelong repercussions in children and adults. There has been stigma around the causes of obesity and its relation to lifestyle choices, without consideration of the genetic and syndromic causes. In this literature review the causes of obesity were investigated, along with the effect on the physiological systems and the enviornmental factors that are continuing the obesity epidemic. Preventing and treating lifestyle obesity is something that is seen to have the greatest effect on youth, especially with intergenerational obesity. Nebraska schools have implemented programs to encourage healthy living, and ongoing research is being implemented to reduce the …
Links Between Anr And Quorum Sensing In Pseudomonas Aeruginosa Biofilms, John H. Hammond, Emily F. Dolben, T. Jarrod Smith, Sabin Bhuju, Deborah Hogan
Links Between Anr And Quorum Sensing In Pseudomonas Aeruginosa Biofilms, John H. Hammond, Emily F. Dolben, T. Jarrod Smith, Sabin Bhuju, Deborah Hogan
Dartmouth Scholarship
In Pseudomonas aeruginosa, the transcription factor Anr controls the cellular response to low oxygen or anoxia. Anr activity is high in oxygen-limited environments, including biofilms and populations associated with chronic infections, and Anr is necessary for persistence in a model of pulmonary infection. In this study, we characterized the Anr regulon in biofilm-grown cells at 1% oxygen in the laboratory strain PAO1 and in a quorum sensing (QS)-deficient clinical isolate, J215. As expected, transcripts related to denitrification, arginine fermentation, high-affinity cytochrome oxidases, and CupA fimbriae were lower in the Δanr derivatives. In addition, we observed that transcripts associated with quorum …
Clustered Regularly Interspaced Short Palindromic Repeat-Dependent, Biofilm-Specific Death Of Pseudomonas Aeruginosa Mediated By Increased Expression Of Phage-Related Genes, Gary E. E. Heussler, Kyle C. Cady, Katja Koeppen, Sabin Bhuju, Bruce A. Stanton, George A. O’Toole
Clustered Regularly Interspaced Short Palindromic Repeat-Dependent, Biofilm-Specific Death Of Pseudomonas Aeruginosa Mediated By Increased Expression Of Phage-Related Genes, Gary E. E. Heussler, Kyle C. Cady, Katja Koeppen, Sabin Bhuju, Bruce A. Stanton, George A. O’Toole
Dartmouth Scholarship
The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (CRISPR/Cas) system is an adaptive immune system present in many archaea and bacteria. CRISPR/Cas systems are incredibly diverse, and there is increasing evidence of CRISPR/Cas systems playing a role in cellular functions distinct from phage immunity. Previously, our laboratory reported one such alternate function in which the type 1-F CRISPR/Cas system of the opportunistic pathogen Pseudomonas aeruginosa strain UCBPP-PA14 (abbreviated as P. aeruginosa PA14) inhibits both biofilm formation and swarming motility when the bacterium is lysogenized by the bacteriophage DMS3. In this study, we demonstrated that the presence of just the DMS3 …
Analysis Of Candida Albicans Mutants Defective In The Cdk8 Module Of Mediator Reveal Links Between Metabolism And Biofilm Formation, Allia K. Lindsay, Diana K. Morales, Zhongle Liu, Nora Grahl, Anda Zhang, Sven D. Willger, Lawrence C. Myers, Deborah A. Hogan
Analysis Of Candida Albicans Mutants Defective In The Cdk8 Module Of Mediator Reveal Links Between Metabolism And Biofilm Formation, Allia K. Lindsay, Diana K. Morales, Zhongle Liu, Nora Grahl, Anda Zhang, Sven D. Willger, Lawrence C. Myers, Deborah A. Hogan
Dartmouth Scholarship
Candida albicans biofilm formation is a key virulence trait that involves hyphal growth and adhesin expression. Pyocyanin (PYO), a phenazine secreted by Pseudomonas aeruginosa, inhibits both C. albicans biofilm formation and development of wrinkled colonies. Using a genetic screen, we identified two mutants, ssn3Δ/Δ and ssn8Δ/Δ, which continued to wrinkle in the presence of PYO. Ssn8 is a cyclin-like protein and Ssn3 is similar to cyclin-dependent kinases; both proteins are part of the heterotetrameric Cdk8 module that forms a complex with the transcriptional co-regulator, Mediator. Ssn3 kinase activity was also required for PYO sensitivity as a kinase dead mutant maintained …
An Mll-Dependent Network Sustains Hematopoiesis, Erika L. Artinger, Bibhu P. Mishra, Kristin M. Zaffuto, Bin E. Li, Elaine K. Y. Chung, Adrian W. Moore, Yufei Chen, Chao Cheng, Patricia Ernst
An Mll-Dependent Network Sustains Hematopoiesis, Erika L. Artinger, Bibhu P. Mishra, Kristin M. Zaffuto, Bin E. Li, Elaine K. Y. Chung, Adrian W. Moore, Yufei Chen, Chao Cheng, Patricia Ernst
Dartmouth Scholarship
The histone methyltransferase Mixed Lineage Leukemia (MLL) is essential to maintain hematopoietic stem cells and is a leukemia protooncogene. Although clustered homeobox genes are well-characterized targets of MLL and MLL fusion oncoproteins, the range of Mll-regulated genes in normal hematopoietic cells remains unknown. Here, we identify and characterize part of the Mll-dependent transcriptional network in hematopoietic stem cells with an integrated approach by using conditional loss-of-function models, genomewide expression analyses, chromatin immunoprecipitation, and functional rescue assays. The Mll-dependent transcriptional network extends well beyond the previously appreciated Hox targets, is comprised of many characterized regulators of self-renewal, and contains target genes …
Scfslimb Ubiquitin Ligase Suppresses Condensin Ii–Mediated Nuclear Reorganization By Degrading Cap-H2, Daniel W. Buster, Scott G. Daniel, Huy Q. Nguyen, Sarah L. Windler, Lara C. Skwarek, Maureen Peterson
Scfslimb Ubiquitin Ligase Suppresses Condensin Ii–Mediated Nuclear Reorganization By Degrading Cap-H2, Daniel W. Buster, Scott G. Daniel, Huy Q. Nguyen, Sarah L. Windler, Lara C. Skwarek, Maureen Peterson
Dartmouth Scholarship
Condensin complexes play vital roles in chromosome condensation during mitosis and meiosis. Condensin II uniquely localizes to chromatin throughout the cell cycle and, in addition to its mitotic duties, modulates chromosome organization and gene expression during interphase. Mitotic condensin activity is regulated by phosphorylation, but mechanisms that regulate condensin II during interphase are unclear. Here, we report that condensin II is inactivated when its subunit Cap-H2 is targeted for degradation by the SCF(Slimb) ubiquitin ligase complex and that disruption of this process dramatically changed interphase chromatin organization. Inhibition of SCF(Slimb) function reorganized interphase chromosomes into dense, compact domains and disrupted …
Non-Identity-Mediated Crispr-Bacteriophage Interaction Mediated Via The Csy And Cas3 Proteins, Kyle C. Cady, George A. O'Toole
Non-Identity-Mediated Crispr-Bacteriophage Interaction Mediated Via The Csy And Cas3 Proteins, Kyle C. Cady, George A. O'Toole
Dartmouth Scholarship
Studies of the Escherichia, Neisseria, Thermotoga, and Mycobacteria clustered regularly interspaced short palindromic repeat (CRISPR) subtypes have resulted in a model whereby CRISPRs function as a defense system against bacteriophage infection and conjugative plasmid transfer. In contrast, we previously showed that the Yersinia-subtype CRISPR region of Pseudomonas aeruginosa strain UCBPP-PA14 plays no detectable role in viral immunity but instead is required for bacteriophage DMS3-dependent inhibition of biofilm formation by P. aeruginosa. The goal of this study is to define the components of the Yersinia-subtype CRISPR region required to mediate this bacteriophage-host interaction. We show that the Yersinia-subtype-specific CRISPR-associated (Cas) proteins …
A Distinct Role For B1b Lymphocytes In T Cell-Independent Immunity, Kishore R. Alugupalli
A Distinct Role For B1b Lymphocytes In T Cell-Independent Immunity, Kishore R. Alugupalli
Department of Microbiology and Immunology Faculty Papers
Pathogenesis of infectious disease is not only determined by the virulence of the microbe but also by the immune status of the host. Vaccination is the most effective means to control infectious diseases. A hallmark of the adaptive immune system is the generation of B cell memory, which provides a long-lasting protective antibody response that is central to the concept of vaccination. Recent studies revealed a distinct function for B1b lymphocytes, a minor subset of mature B cells that closely resembles that of memory B cells in a number of aspects. In contrast to the development of conventional B cell …
A Developmental Cycle Masks Output From The Circadian Oscillator Under Conditions Of Choline Deficiency In Neurospora, Mi Shi, Luis F. Larrondo, Jennifer J. Loros, Jay C. Dunlap
A Developmental Cycle Masks Output From The Circadian Oscillator Under Conditions Of Choline Deficiency In Neurospora, Mi Shi, Luis F. Larrondo, Jennifer J. Loros, Jay C. Dunlap
Dartmouth Scholarship
In Neurospora, metabolic oscillators coexist with the circadian transcriptional/translational feedback loop governed by the FRQ (Frequency) and WC (White Collar) proteins. One of these, a choline deficiency oscillator (CDO) observed in chol-1 mutants grown under choline starvation, drives an uncompensated long-period developmental cycle ( approximately 60-120 h). To assess possible contributions of this metabolic oscillator to the circadian system, molecular and physiological rhythms were followed in liquid culture under choline starvation, but these only confirmed that an oscillator with a normal circadian period length can run under choline starvation. This finding suggested that long-period developmental cycles elicited by nutritional stress …
Let-7 Expression Defines Two Differentiation Stages Of Cancer, Scott Shell, Sun-Mi Park, Amir Reza Radjabi, Robert Schickel, Emily Kistner, David Jewell
Let-7 Expression Defines Two Differentiation Stages Of Cancer, Scott Shell, Sun-Mi Park, Amir Reza Radjabi, Robert Schickel, Emily Kistner, David Jewell
Dartmouth Scholarship
The early phases of carcinogenesis resemble embryonic development, often involving the reexpression of embryonic mesenchymal genes. The NCI60 panel of human tumor cell lines can genetically be subdivided into two superclusters (SCs) that correspond to CD95 Type I and II cells. SC1 cells are characterized by a mesenchymal and SC2 cells by an epithelial gene signature, suggesting that SC1 cells represent less differentiated, advanced stages of cancer. miRNAs are small 20- to 22-nucleotide-long noncoding RNAs that inhibit gene expression at the posttranscriptional level. By performing miRNA expression analysis on 10 Type I and 10 Type II cells, we have determined …
The Pseudomonas Aeruginosa Secreted Protein Pa2934 Decreases Apical Membrane Expression Of The Cystic Fibrosis Transmembrane Conductance Regulator, Daniel P. Maceachran, Siying Ye, Jennifer M. Bomberger, Deborah A. Hogan, Agnieszka Swiatecka-Urban, Bruce Stanton, George A. O'Toole
The Pseudomonas Aeruginosa Secreted Protein Pa2934 Decreases Apical Membrane Expression Of The Cystic Fibrosis Transmembrane Conductance Regulator, Daniel P. Maceachran, Siying Ye, Jennifer M. Bomberger, Deborah A. Hogan, Agnieszka Swiatecka-Urban, Bruce Stanton, George A. O'Toole
Dartmouth Scholarship
We previously reported that Pseudomonas aeruginosa PA14 secretes a protein that can reduce the apical membrane expression of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Here we report that we have used a proteomic approach to identify this secreted protein as PA2934 [corrected], and we have named the gene cif, for CFTR inhibitory factor. We demonstrate that Cif is a secreted protein and is found associated with outer membrane-derived vesicles. Expression of Cif in Escherichia coli and purification of the C-terminal six-His-tagged Cif protein showed that Cif is necessary and sufficient to mediate the reduction in apical membrane expression …
Circadian Rhythmicity By Autocatalysis, Arun Mehra, Christian I. Hong, Mi Shi, Jennifer J. Loros, Jay C. Dunlap, Peter Ruoff
Circadian Rhythmicity By Autocatalysis, Arun Mehra, Christian I. Hong, Mi Shi, Jennifer J. Loros, Jay C. Dunlap, Peter Ruoff
Dartmouth Scholarship
The temperature compensated in vitro oscillation of cyanobacterial KaiC phosphorylation, the first example of a thermodynamically closed system showing circadian rhythmicity, only involves the three Kai proteins (KaiA, KaiB, and KaiC) and ATP. In this paper, we describe a model in which the KaiA- and KaiB-assisted autocatalytic phosphorylation and dephosphorylation of KaiC are the source for circadian rhythmicity. This model, based upon autocatalysis instead of transcription-translation negative feedback, shows temperature-compensated circadian limit-cycle oscillations with KaiC phosphorylation profiles and has period lengths and rate constant values that are consistent with experimental observations.
A Drosophila Deg/Enac Channel Subunit Is Required For Male Response To Female Pheromones, Heping Lin, Kevin J. Mann, Elena Starostina, Ronald D. Kinser, Claudio W. Pikielny
A Drosophila Deg/Enac Channel Subunit Is Required For Male Response To Female Pheromones, Heping Lin, Kevin J. Mann, Elena Starostina, Ronald D. Kinser, Claudio W. Pikielny
Dartmouth Scholarship
Odorants and pheromones as well as sweet- and bitter-tasting small molecules are perceived through activation of G protein-coupled chemosensory receptors. In contrast, gustatory detection of salty and sour tastes may involve direct gating of sodium channels of the DEG/ENaC family by sodium and hydrogen ions, respectively. We have found that ppk25, a Drosophila melanogaster gene encoding a DEG/ENaC channel subunit, is expressed at highest levels in the male appendages responsible for gustatory and olfactory detection of female pheromones: the legs, wings, and antennae. Mutations in the ppk25 gene reduce or even abolish male courtship response to females in the dark, …
A Three-Component Regulatory System Regulates Biofilm Maturation And Type Iii Secretion In Pseudomonas Aeruginosa, Sherry L. Kuchma, John P. Connolly, George A. O'Toole
A Three-Component Regulatory System Regulates Biofilm Maturation And Type Iii Secretion In Pseudomonas Aeruginosa, Sherry L. Kuchma, John P. Connolly, George A. O'Toole
Dartmouth Scholarship
Biofilms are structured communities found associated with a wide range of surfaces. Here we report the identification of a three-component regulatory system required for biofilm maturation by Pseudomonas aeruginosa strain PA14. A transposon mutation that altered biofilm formation in a 96-well dish assay originally defined this locus, which is comprised of genes for a putative sensor histidine kinase and two response regulators and has been designated sadARS. Nonpolar mutations in any of the sadARS genes result in biofilms with an altered mature structure but do not confer defects in growth or early biofilm formation, swimming, or twitching motility. After …
Endothelial-Specific Expression Of Caveolin-1 Impairs Microvascular Permeability And Angiogenesis, Philip M. Bauer, Jun Yu, Yan Chen, Reed Hickey, Pascal N. Bernatchez, Robin Looft-Wilson, Yan Huang, Frank Giordano, Radu V. Stan, William C. Sessa
Endothelial-Specific Expression Of Caveolin-1 Impairs Microvascular Permeability And Angiogenesis, Philip M. Bauer, Jun Yu, Yan Chen, Reed Hickey, Pascal N. Bernatchez, Robin Looft-Wilson, Yan Huang, Frank Giordano, Radu V. Stan, William C. Sessa
Dartmouth Scholarship
The functions of caveolae and/or caveolins in intact animals are beginning to be explored. Here, by using endothelial cell-specific transgenesis of the caveolin-1 (Cav-1) gene in mice, we show the critical role of Cav-1 in several postnatal vascular paradigms. First, increasing levels of Cav-1 do not increase caveolae number in the endothelium in vivo. Second, despite a lack of quantitative changes in organelle number, endothelial-specific expression of Cav-1 impairs endothelial nitric oxide synthase activation, endothelial barrier function, and angiogenic responses to exogenous VEGF and tissue ischemia. In addition, VEGF-mediated phosphorylation of Akt and its substrate, endothelial nitric oxide synthase, were …
An Intramolecular Association Between Two Domains Of The Protein Kinase Fused Is Necessary For Hedgehog Signaling, Manuel Ascano Jr., David J. Robbins
An Intramolecular Association Between Two Domains Of The Protein Kinase Fused Is Necessary For Hedgehog Signaling, Manuel Ascano Jr., David J. Robbins
Dartmouth Scholarship
The protein kinase Fused (Fu) is an integral member of the Hedgehog (Hh) signaling pathway. Although genetic studies demonstrate that Fu is required for the regulation of the Hh pathway, the mechanistic role that it plays remains largely unknown. Given our difficulty in developing an in vitro kinase assay for Fu, we reasoned that the catalytic activity of Fu might be highly regulated. Several mechanisms are known to regulate protein kinases, including self-association in either an intra- or an intermolecular fashion. Here, we provide evidence that Hh regulates Fu through intramolecular association between its kinase domain (ΔFu) and its carboxyl-terminal …
Sadb Is Required For The Transition From Reversible To Irreversible Attachment During Biofilm Formation By Pseudomonas Aeruginosa Pa14, Nicky C. Caiazza, George A. O'Toole
Sadb Is Required For The Transition From Reversible To Irreversible Attachment During Biofilm Formation By Pseudomonas Aeruginosa Pa14, Nicky C. Caiazza, George A. O'Toole
Dartmouth Scholarship
Current models of biofilm formation by Pseudomonas aeruginosa propose that (i) planktonic cells become surface associated in a monolayer, (ii) surface-associated cells form microcolonies by clonal growth and/or aggregation, (iii) microcolonies transition to a mature biofilm comprised of exopolysaccharide-encased macrocolonies, and (iv) cells exit the mature biofilm and reenter the planktonic state. Here we report a new class of P. aeruginosa biofilm mutant that defines the transition from reversible to irreversible attachment and is thus required for monolayer formation. The transposon insertion carried by the sadB199 mutant was mapped to open reading frame PA5346 of P. aeruginosa PA14 and encodes …
The Nad(P)H Oxidase Homolog Nox4 Modulates Insulin-Stimulated Generation Of H202 And Plays An Integral Role In Insulin Signal Transduction, Kalyankar Mahadev, Hiroyuki Motoshima, Xiangdong Wu, Jean Marie Ruddy, Rebecca S. Arnold, Guangjie Cheng, J. David Lambeth, Barry J. Goldstein
The Nad(P)H Oxidase Homolog Nox4 Modulates Insulin-Stimulated Generation Of H202 And Plays An Integral Role In Insulin Signal Transduction, Kalyankar Mahadev, Hiroyuki Motoshima, Xiangdong Wu, Jean Marie Ruddy, Rebecca S. Arnold, Guangjie Cheng, J. David Lambeth, Barry J. Goldstein
Department of Medicine Faculty Papers
Insulin stimulation of target cells elicits a burst of H2O2 that enhances tyrosine phosphorylation of the insulin receptor and its cellular substrate proteins as well as distal signaling events in the insulin action cascade. The molecular mechanism coupling the insulin receptor with the cellular oxidant-generating apparatus has not been elucidated. Using reverse transcription-PCR and Northern blot analyses, we found that Nox4, a homolog of gp91phox, the phagocytic NAD(P)H oxidase catalytic subunit, is prominently expressed in insulin-sensitive adipose cells. Adenovirus-mediated expression of Nox4 deletion constructs lacking NAD(P)H or FAD/NAD(P)H cofactor binding domains acted in a dominant-negative …
Rhythmic Binding Of A White Collar-Containing Complex To The Frequency Promoter Is Inhibited By Frequency, Allan C. Froehlich, Jennifer J. Loros, Jay C. Dunlap
Rhythmic Binding Of A White Collar-Containing Complex To The Frequency Promoter Is Inhibited By Frequency, Allan C. Froehlich, Jennifer J. Loros, Jay C. Dunlap
Dartmouth Scholarship
The biological clock of Neurospora crassa includes interconnected transcriptional and translational feedback loops that cause both the transcript and protein encoded by the frequency gene (frq) to undergo the robust daily oscillations in abundance, which are essential for clock function. To understand better the mechanism generating rhythmic frq transcript, reporter constructs were used to show that the oscillation in frq message is transcriptionally regulated, and a single cis-acting element in the frq promoter, the Clock Box (C box), is both necessary and sufficient for this rhythmic transcription. Nuclear protein extracts used in binding assays revealed that a White Collar (WC)-1- …
A Genetic Lesion That Arrests Plasma Cell Homing To The Bone Marrow, Loren D. Erickson, Ling-Li Lin, Biyan Duan, Laurence Morel, Randolph J. Noelle
A Genetic Lesion That Arrests Plasma Cell Homing To The Bone Marrow, Loren D. Erickson, Ling-Li Lin, Biyan Duan, Laurence Morel, Randolph J. Noelle
Dartmouth Scholarship
The coordinated regulation of chemokine responsiveness plays a critical role in the development of humoral immunity. After antigen challenge and B cell activation, the emerging plasma cells (PCs) undergo CXCL12-induced chemotaxis to the bone marrow, where they produce Ab and persist. Here we show that PCs, but not B cells or T cells from lupus-prone NZM mice, are deficient in CXCL12-induced migration. PC unresponsiveness to CXCL12 results in a marked accumulation of PCs in the spleen of mice, and a concordant decrease in bone marrow PCs. Unlike normal mice, in NZM mice, a majority of the splenic PCs are long-lived. …
Circadian Clock-Specific Roles For The Light Response Protein White Collar-2, Michael A. Collett, Jay C. Dunlap, Jennifer J. Loros
Circadian Clock-Specific Roles For The Light Response Protein White Collar-2, Michael A. Collett, Jay C. Dunlap, Jennifer J. Loros
Dartmouth Scholarship
To understand the role of white collar-2 in theNeurospora circadian clock, we examined alleles ofwc-2 thought to encode partially functional proteins. We found that wc-2 allele ER24 contained a conservative mutation in the zinc finger. This mutation results in reduced levels of circadian rhythm-critical clock gene products, frq mRNA and FRQ protein, and in a lengthened period of the circadian clock. In addition, this mutation altered a second canonical property of the clock, temperature compensation: as temperature increased, period length decreased substantially. This temperature compensation defect correlated with a temperature-dependent increase in overall FRQ protein levels, with the …
The Growth Of Simian Virus 40 (Sv40) Host Range/Adenovirus Helper Function Mutants In An African Green Monkey Cell Line That Constitutively Expresses The Sv40 Agnoprotein., Terryl P. Stacy, Michele Chamberlain, Susan Carswell, Charles N. Cole
The Growth Of Simian Virus 40 (Sv40) Host Range/Adenovirus Helper Function Mutants In An African Green Monkey Cell Line That Constitutively Expresses The Sv40 Agnoprotein., Terryl P. Stacy, Michele Chamberlain, Susan Carswell, Charles N. Cole
Dartmouth Scholarship
The simian virus 40 T-antigen carboxy-terminal mutants, dlA2459 and dlA2475, are cell line and temperature dependent for growth and plaque formation in monkey kidney cells. Although these mutants did form plaques on BSC-1 cells at 37 degrees C, they were about fivefold less efficient for plaque formation than wild-type simian virus 40. These mutants did not grow in CV-1 cells and did not synthesize agnoprotein in those cells. CV-1 cells which constitutively express the agnoprotein were permissive for mutant plaque formation. However, late mRNAs, virion proteins, and progeny virion yields did not accumulate to wild-type levels during mutant infection of …