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Articles 1 - 30 of 37
Full-Text Articles in Life Sciences
Sara Of Staphylococcus Aureus Binds To The Sara Promoter To Regulate Gene Expression, Ambrose L. Cheung, Koren Nishina, Adhar C. Manna
Sara Of Staphylococcus Aureus Binds To The Sara Promoter To Regulate Gene Expression, Ambrose L. Cheung, Koren Nishina, Adhar C. Manna
Dartmouth Scholarship
The 375-bp sarA open reading frame is driven by three promoters, P1, P3, and P2. Using gel shift and DNase I footprinting assays, we found that SarA binds to two 26-bp sequences and one 31-bp sequence within the P1 and P3 promoters, respectively. Together with the results of transcription analyses, our data indicate that SarA binds to its own promoter to down-regulate sarA expression.
Gene Response Profiles For Daphnia Pulex Exposed To The Environmental Stressor Cadmium Reveals Novel Crustacean Metallothioneins, Joseph R. Shaw, John K. Colbourne, Jennifer C. Davey, Stephen P. Glaholt, Thomas H. Hampton, Celia Y. Chen, Carol L. Folt, Joshua W. Hamilton
Gene Response Profiles For Daphnia Pulex Exposed To The Environmental Stressor Cadmium Reveals Novel Crustacean Metallothioneins, Joseph R. Shaw, John K. Colbourne, Jennifer C. Davey, Stephen P. Glaholt, Thomas H. Hampton, Celia Y. Chen, Carol L. Folt, Joshua W. Hamilton
Dartmouth Scholarship
Genomic research tools such as microarrays are proving to be important resources to study the complex regulation of genes that respond to environmental perturbations. A first generation cDNA microarray was developed for the environmental indicator species Daphnia pulex, to identify genes whose regulation is modulated following exposure to the metal stressor cadmium. Our experiments revealed interesting changes in gene transcription that suggest their biological roles and their potentially toxicological features in responding to this important environmental contaminant.
N-Glycan Modification In Aspergillus Species, Elke Kainz, Andreas Gallmetzer, Christian Hatzl, Juergen H. Nett, Huijuan Li, Thorsten Schinko, Robert Pachlinger, Harald Berger, Yazmid Reyes-Dominguez, Andreas Bernreiter, Tillmann Gerngross, Stefan Wildt, Joseph Strauss
N-Glycan Modification In Aspergillus Species, Elke Kainz, Andreas Gallmetzer, Christian Hatzl, Juergen H. Nett, Huijuan Li, Thorsten Schinko, Robert Pachlinger, Harald Berger, Yazmid Reyes-Dominguez, Andreas Bernreiter, Tillmann Gerngross, Stefan Wildt, Joseph Strauss
Dartmouth Scholarship
The production by filamentous fungi of therapeutic glycoproteins intended for use in mammals is held back by the inherent difference in protein N-glycosylation and by the inability of the fungal cell to modify proteins with mammalian glycosylation structures. Here, we report protein N-glycan engineering in two Aspergillus species. We functionally expressed in the fungal hosts heterologous chimeric fusion proteins containing different localization peptides and catalytic domains. . This strategy allowed the isolation of a strain with a functional -1,2-mannosidase producing increased amounts of N-glycans of the Man 5 GlcNAc 2 type. This strain was further engineered by the introduction of …
The Role Of Carcinine In Signaling At The Drosophila Photoreceptor Synapse, Brendan A. Gavin, Susan E. Arruda, Patrick J. Dolph
The Role Of Carcinine In Signaling At The Drosophila Photoreceptor Synapse, Brendan A. Gavin, Susan E. Arruda, Patrick J. Dolph
Dartmouth Scholarship
The Drosophila melanogaster photoreceptor cell has long served as a model system for researchers focusing on how animal sensory neurons receive information from their surroundings and translate this information into chemical and electrical messages. Electroretinograph (ERG) analysis of Drosophila mutants has helped to elucidate some of the genes involved in the visual transduction pathway downstream of the photoreceptor cell, and it is now clear that photoreceptor cell signaling is dependent upon the proper release and recycling of the neurotransmitter histamine. While the neurotransmitter transporters responsible for clearing histamine, and its metabolite carcinine, from the synaptic cleft have remained unknown, a …
Genome-Wide Transcriptional Profiling Of The Cyclic Amp-Dependent Signaling Pathway During Morphogenic Transitions Of Candida Albicans, Yong-Sun Bahn, Matthew Molenda, Janet F. Staab, Courtney A. Lyman, Laura J. Gordon, Paula Sundstrom
Genome-Wide Transcriptional Profiling Of The Cyclic Amp-Dependent Signaling Pathway During Morphogenic Transitions Of Candida Albicans, Yong-Sun Bahn, Matthew Molenda, Janet F. Staab, Courtney A. Lyman, Laura J. Gordon, Paula Sundstrom
Dartmouth Scholarship
Candida albicans is an opportunistic human fungal pathogen that causes systemic candidiasis as well as superficial mucosal candidiasis. In response to the host environment, C. albicans transitions between yeast and hyphal forms. In particular, hyphal growth is important in facilitating adhesion and invasion of host tissues, concomitant with the expression of various hypha-specific virulence factors. In previous work, we showed that the cyclic AMP (cAMP) signaling pathway plays a crucial role in morphogenic transitions and virulence of C. albicans by studying genes encoding adenylate cyclase-associated protein (CAP1) and high-affinity phosphodiesterase (PDE2) (Y. S. Bahn, J. Staab, and P. Sundstrom, Mol. …
A Conserved Cam- And Radial Spoke–Associated Complex Mediates Regulation Of Flagellar Dynein Activity, Erin E. Dymek, Elizabeth F. Smith
A Conserved Cam- And Radial Spoke–Associated Complex Mediates Regulation Of Flagellar Dynein Activity, Erin E. Dymek, Elizabeth F. Smith
Dartmouth Scholarship
For virtually all cilia and eukaryotic flagella, the second messengers calcium and cyclic adenosine monophosphate are implicated in modulating dynein- driven microtubule sliding to regulate beating. Calmodulin (CaM) localizes to the axoneme and is a key calcium sensor involved in regulating motility. Using immunoprecipitation and mass spectrometry, we identify members of a CaM-containing complex that are involved in regulating dynein activity. This complex includes flagellar-associated protein 91 (FAP91), which shares considerable sequence similarity to AAT-1, a protein originally identified in testis as an A-kinase anchor protein (AKAP)- binding protein. FAP91 directly interacts with radial spoke protein 3 (an AKAP), which …
Characterization Of Mazfsa, An Endoribonuclease From Staphylococcus Aureus, Zhibiao Fu, Niles P. Donegan, Guido Memmi, Ambrose L. Cheung
Characterization Of Mazfsa, An Endoribonuclease From Staphylococcus Aureus, Zhibiao Fu, Niles P. Donegan, Guido Memmi, Ambrose L. Cheung
Dartmouth Scholarship
The mazEF homologs of Staphylococcus aureus, designated mazEF(sa), have been shown to cotranscribe with the sigB operon under stress conditions. In this study, we showed that MazEF(Sa), as with their Escherichia coli counterparts, compose a toxin-antitoxin module wherein MazF(Sa) leads to rapid cell growth arrest and loss in viable CFU upon overexpression. MazF(Sa) is a novel sequence-specific endoribonuclease which cleaves mRNA to inhibit protein synthesis. Using ctpA mRNA as the model substrate both in vitro and in vivo, we demonstrated that MazF(Sa) cleaves single-strand RNA preferentially at the 5' side of the first U or 3' side of the second …
The Small Rna Repertoire Of Dictyostelium Discoideum And Its Regulation By Components Of The Rnai Pathway, Andrea Hinas, Johan Reimegård, E. Gerhart H. Wagner, Wolfgang Nellen, Victor R. Ambros, Fredrik Soderbum
The Small Rna Repertoire Of Dictyostelium Discoideum And Its Regulation By Components Of The Rnai Pathway, Andrea Hinas, Johan Reimegård, E. Gerhart H. Wagner, Wolfgang Nellen, Victor R. Ambros, Fredrik Soderbum
Dartmouth Scholarship
Small RNAs play crucial roles in regulation of gene expression in many eukaryotes. Here, we report the cloning and characterization of 18–26 nt RNAs in the social amoeba Dictyostelium discoideum . This survey uncovered developmentally regulated microRNA candidates whose biogenesis, at least in one case, is dependent on a Dicer homolog, DrnB. Furthermore, we identified a large number of 21 nt RNAs originating from the DIRS-1 retrotransposon, clusters of which have been suggested to constitute centromeres. Small RNAs from another retrotransposon, Skipper, were significantly up-regulated in strains depleted of the second Dicer-like protein, DrnA, and a putative RNA-dependent RNA polymerase, …
Role Of Actin Cytoskeletal Dynamics In Activation Of The Cyclic Amp Pathway And Hwp1 Gene Expression In Candida Albicans, Michael J. Wolyniak, Paula Sundstrom
Role Of Actin Cytoskeletal Dynamics In Activation Of The Cyclic Amp Pathway And Hwp1 Gene Expression In Candida Albicans, Michael J. Wolyniak, Paula Sundstrom
Dartmouth Scholarship
Changes in gene expression during reversible bud-hypha transitions of the opportunistic fungal pathogen Candida albicans permit adaptation to environmental conditions that are critical for proliferation in host tissues. Our previous work has shown that the hypha-specific adhesin gene HWP1 is up-regulated by the cyclic AMP (cAMP) signaling pathway. However, little is known about the potential influences of determinants of cell morphology on HWP1 gene expression. We found that blocking hypha formation with cytochalasin A, which destabilizes actin filaments, and with latrunculin A, which sequesters actin monomers, led to a loss of HWP1 gene expression. In contrast, high levels of HWP1 …
Spatial Scaling Of Avian Population Dynamics: Population Abundance, Growth Rate, And Variability, Jason Jones, Patrick J. Doran, Richard T. Holmes
Spatial Scaling Of Avian Population Dynamics: Population Abundance, Growth Rate, And Variability, Jason Jones, Patrick J. Doran, Richard T. Holmes
Dartmouth Scholarship
Synchrony in population fluctuations has been identified as an important component of population dynamics. In a previous study, we determined that local‐scale (<15‐km) spatial synchrony of bird populations in New England was correlated with synchronous fluctuations in lepidopteran larvae abundance and with the North Atlantic Oscillation. Here we address five questions that extend the scope of our earlier study using North American Breeding Bird Survey data. First, do bird populations in eastern North America exhibit spatial synchrony in abundances at scales beyond those we have documented previously? Second, does spatial synchrony depend on what population metric is analyzed (e.g., abundance, growth rate, or variability)? Third, is there geographic concordance in where species exhibit synchrony? Fourth, for those species that exhibit significant geographic concordance, are there landscape and habitat variables that contribute to the observed patterns? Fifth, is spatial synchrony affected by a species' life history traits? Significant spatial synchrony was common and its magnitude was dependent on the population metric analyzed. Twenty‐four of 29 species examined exhibited significant synchrony in population abundance: mean local autocorrelation (ρ) = 0.15; mean spatial extent (mean distance where ρ = 0) = 420.7 km. Five of the 29 species exhibited significant synchrony in annual population growth rate (mean local autocorrelation = 0.06, mean distance = 457.8 km). Ten of the 29 species exhibited significant synchrony in population abundance variability (mean local autocorrelation = 0.49, mean distance = 413.8 km). Analyses of landscape structure indicated that habitat variables were infrequent contributors to spatial synchrony. Likewise, we detected no effects of life history traits on synchrony in population abundance or growth rate. However, short‐distance migrants exhibited more spatially extensive synchrony in population variability than either year‐round residents or long‐distance migrants. The dissimilarity of the spatial extent of synchrony across species suggests that most populations are not regulated at similar spatial scales. The spatial scale of the population synchrony patterns we describe is likely larger than the actual scale of population regulation, and in turn, the scale of population regulation is undoubtedly larger than the scale of individual ecological requirements.
Manipulating Underdetermination In Scientific Controversy: The Case Of The Molecular Clock, Michael Dietrich, Robert A. Skipper
Manipulating Underdetermination In Scientific Controversy: The Case Of The Molecular Clock, Michael Dietrich, Robert A. Skipper
Dartmouth Scholarship
Where there are cases of underdetermination in scientific controversies, such as the case of the molecular clock, scientists may direct the course and terms of dispute by playing off the multidimensional framework of theory evaluation. This is because assessment strategies themselves are underdetermined. Within the framework of assessment, there are a variety of trade-offs between different strategies as well as shifting emphases as specific strategies are given more or less weight in assessment situations. When a strategy is underdetermined, scientists can change the dynamics of a controversy by making assessments using different combinations of evaluation strategies and/or weighting whatever strategies …
Fully Codon-Optimized Luciferase Uncovers Novel Temperature Characteristics Of The Neurospora Clock, Van D. Gooch, Arun Mehra, Luis F. Larrondo, Julie Fox, Melissa Touroutoutoudis, Jennifer J. Loros, Jay C. Dunlap
Fully Codon-Optimized Luciferase Uncovers Novel Temperature Characteristics Of The Neurospora Clock, Van D. Gooch, Arun Mehra, Luis F. Larrondo, Julie Fox, Melissa Touroutoutoudis, Jennifer J. Loros, Jay C. Dunlap
Dartmouth Scholarship
We report the complete reconstruction of the firefly luciferase gene, fully codon optimized for expression in Neurospora crassa. This reporter enhances light output by approximately 4 log orders over that with previously available versions, now producing light that is visible to the naked eye and sufficient for monitoring the activities of many poorly expressed genes. Time lapse photography of strains growing in race tubes, in which the frq or eas/ccg-2 promoter is used to drive luciferase, shows the highest levels of luciferase activity near the growth front and newly formed conidial bands. Further, we have established a sorbose medium colony …
The Yeast Integral Membrane Protein Apq12 Potentially Links Membrane Dynamics To Assembly Of Nuclear Pore Complexes, John J. Scarcelli, Christin A. Hodge, Charles N. Cole
The Yeast Integral Membrane Protein Apq12 Potentially Links Membrane Dynamics To Assembly Of Nuclear Pore Complexes, John J. Scarcelli, Christin A. Hodge, Charles N. Cole
Dartmouth Scholarship
Although the structure and function of components of the nuclear pore complex (NPC) have been the focus of many studies, relatively little is known about NPC biogenesis. In this study, we report that Apq12 is required for efficient NPC biogenesis in Saccharomyces cerevisiae. Apq12 is an integral membrane protein of the nuclear envelope (NE) and endoplasmic reticulum. Cells lacking Apq12 are cold sensitive for growth, and a subset of their nucleoporins (Nups), those that are primarily components of the cytoplasmic fibrils of the NPC, mislocalize to the cytoplasm. APQ12 deletion also causes defects in NE morphology. In the absence of …
A Serratia Marcescens Oxyr Homolog Mediates Surface Attachment And Biofilm Formation, Robert M. Q. Shanks, Nicholas A. Stella, Eric J. Kalivoda, Megan R. Doe
A Serratia Marcescens Oxyr Homolog Mediates Surface Attachment And Biofilm Formation, Robert M. Q. Shanks, Nicholas A. Stella, Eric J. Kalivoda, Megan R. Doe
Dartmouth Scholarship
OxyR is a conserved bacterial transcription factor with a regulatory role in oxidative stress response. From a genetic screen for genes that modulate biofilm formation in the opportunistic pathogen Serratia marcescens, mutations in an oxyR homolog and predicted fimbria structural genes were identified. S. marcescens oxyR mutants were severely impaired in biofilm formation, in contrast to the hyperbiofilm phenotype exhibited by oxyR mutants of Escherichia coli and Burkholderia pseudomallei. Further analysis revealed that OxyR plays a role in the primary attachment of cells to a surface. Similar to what is observed in other bacterial species, S. marcescens OxyR …
Microbial Nitrogen Limitation Increases Decomposition, Joseph M. Craine, Carl Morrow, Noah Fierer
Microbial Nitrogen Limitation Increases Decomposition, Joseph M. Craine, Carl Morrow, Noah Fierer
Dartmouth Scholarship
With anthropogenic nutrient inputs to ecosystems increasing globally, there are long-standing, fundamental questions about the role of nutrients in the decomposition of organic matter. We tested the effects of exogenous nitrogen and phosphorus inputs on litter decomposition across a broad suite of litter and soil types. In one experiment, C mineralization was compared across a wide array of plants individually added to a single soil, while in the second, C mineralization from a single substrate was compared across 50 soils. Counter to basic stoichiometric decomposition theory, low N availability can increase litter decomposition as microbes use labile substrates to acquire …
A Novel Ensemble Learning Method For De Novo Computational Identification Of Dna Binding Sites, Arijit Chakravarty, Jonathan M. Carlson, Radhika S. Khetani, Robert H H. Gross
A Novel Ensemble Learning Method For De Novo Computational Identification Of Dna Binding Sites, Arijit Chakravarty, Jonathan M. Carlson, Radhika S. Khetani, Robert H H. Gross
Dartmouth Scholarship
Despite the diversity of motif representations and search algorithms, the de novo computational identification of transcription factor binding sites remains constrained by the limited accuracy of existing algorithms and the need for user-specified input parameters that describe the motif being sought.ResultsWe present a novel ensemble learning method, SCOPE, that is based on the assumption that transcription factor binding sites belong to one of three broad classes of motifs: non-degenerate, degenerate and gapped motifs. SCOPE employs a unified scoring metric to combine the results from three motif finding algorithms each aimed at the discovery of one of these classes of motifs. …
Sampling Daphnia's Expressed Genes: Preservation, Expansion And Invention Of Crustacean Genes With Reference To Insect Genomes, John K. Colbourne, Brian D. Eads, Joseph Shaw, Elizabeth Bohuski, Darren Bauer, Justen Andrews
Sampling Daphnia's Expressed Genes: Preservation, Expansion And Invention Of Crustacean Genes With Reference To Insect Genomes, John K. Colbourne, Brian D. Eads, Joseph Shaw, Elizabeth Bohuski, Darren Bauer, Justen Andrews
Dartmouth Scholarship
Functional and comparative studies of insect genomes have shed light on the complement of genes, which in part, account for shared morphologies, developmental programs and life-histories. Contrasting the gene inventories of insects to those of the nematodes provides insight into the genomic changes responsible for their diversification. However, nematodes have weak relationships to insects, as each belongs to separate animal phyla. A better outgroup to distinguish lineage specific novelties would include other members of Arthropoda. For example, crustaceans are close allies to the insects (together forming Pancrustacea) and their fascinating aquatic lifestyle provides an important comparison for understanding the genetic …
Regulation Of Meiotic Cohesion And Chromosome Core Morphogenesis During Pachytene In Drosophila Oocytes, Radhika S. Khetani, Sharon E. Bickel
Regulation Of Meiotic Cohesion And Chromosome Core Morphogenesis During Pachytene In Drosophila Oocytes, Radhika S. Khetani, Sharon E. Bickel
Dartmouth Scholarship
During meiosis, cohesion between sister chromatids is required for normal levels of homologous recombination, maintenance of chiasmata and accurate chromosome segregation during both divisions. In Drosophila, null mutations in the ord gene abolish meiotic cohesion, although how ORD protein promotes cohesion has remained elusive. We show that SMC subunits of the cohesin complex colocalize with ORD at centromeres of ovarian germ-line cells. In addition, cohesin SMCs and ORD are visible along the length of meiotic chromosomes during pachytene and remain associated with chromosome cores following DNase I digestion. In flies lacking ORD activity, cohesin SMCs fail to accumulate at oocyte …
Bifa, A Cyclic-Di-Gmp Phosphodiesterase, Inversely Regulates Biofilm Formation And Swarming Motility By Pseudomonas Aeruginosa Pa14, Sherry L. Kuchma, Kimberly M. Brothers, Judith H. Merritt, Nicole T. Liberati, Frederick M. Ausubel, George A. O'Toole
Bifa, A Cyclic-Di-Gmp Phosphodiesterase, Inversely Regulates Biofilm Formation And Swarming Motility By Pseudomonas Aeruginosa Pa14, Sherry L. Kuchma, Kimberly M. Brothers, Judith H. Merritt, Nicole T. Liberati, Frederick M. Ausubel, George A. O'Toole
Dartmouth Scholarship
The intracellular signaling molecule, cyclic-di-GMP (c-di-GMP), has been shown to influence bacterial behaviors, including motility and biofilm formation. We report the identification and characterization of PA4367, a gene involved in regulating surface-associated behaviors in Pseudomonas aeruginosa. The PA4367 gene encodes a protein with an EAL domain, associated with c-di-GMP phosphodiesterase activity, as well as a GGDEF domain, which is associated with a c-di-GMP-synthesizing diguanylate cyclase activity. Deletion of the PA4367 gene results in a severe defect in swarming motility and a hyperbiofilm phenotype; thus, we designate this gene bifA, for biofilm formation. We show that BifA localizes to the inner …
Beyond The Boss And The Boys: Women And The Division Of Labor In Drosophila Genetics In The United States, 1934-1970, Michael Dietrich
Beyond The Boss And The Boys: Women And The Division Of Labor In Drosophila Genetics In The United States, 1934-1970, Michael Dietrich
Dartmouth Scholarship
The vast network of Drosphila geneticists spawned by Thomas Hunt Morgan's fly room in the early 20th century has justifiably received a significant amount of scholarly attention. However, most accounts of the history of Drosophila genetics focus heavily on the \"boss and the boys,\" rather than the many other laboratory groups which also included large numbers of women. Using demographic information extracted from the Drosophila Information Service directories from 1934 to 1970, we offer a profile of the gendered division of labor within Drosophila genetics in the United States during the middle decades of the 20th century. Our analysis of …
The Kinesin-13 Proteins Kif2a, Kif2b, And Kif2c/Mcak Have Distinct Roles During Mitosis In Human Cells, Amity L. Manning, Neil J. Ganem, Samuel F. Bakhoum, Michael Wagenbach, Linda Wordeman, Duane A. Compton
The Kinesin-13 Proteins Kif2a, Kif2b, And Kif2c/Mcak Have Distinct Roles During Mitosis In Human Cells, Amity L. Manning, Neil J. Ganem, Samuel F. Bakhoum, Michael Wagenbach, Linda Wordeman, Duane A. Compton
Dartmouth Scholarship
The human genome has three unique genes coding for kinesin-13 proteins called Kif2a, Kif2b, and MCAK (Kif2c). Kif2a and MCAK have documented roles in mitosis, but the function of Kif2b has not been defined. Here, we show that Kif2b is expressed at very low levels in cultured cells and that GFP-Kif2b localizes predominately to centrosomes and midbodies, but also to spindle microtubules and transiently to kinetochores. Kif2b-deficient cells assemble monopolar or disorganized spindles. Chromosomes in Kif2b-deficient cells show typical kinetochore-microtubule attachments, but the velocity of movement is reduced ∼80% compared with control cells. Some Kif2b-deficient cells attempt anaphase, but the …
Parasites Alter Community Structure, Chelsea L. Wood, James E. Byers, Kathryn L. Cottingham, Irit Altman
Parasites Alter Community Structure, Chelsea L. Wood, James E. Byers, Kathryn L. Cottingham, Irit Altman
Dartmouth Scholarship
Parasites often play an important role in modifying the physiology and behavior of their hosts and may, consequently, mediate the influence hosts have on other components of an ecological community. Along the northern Atlantic coast of North America, the dominant herbivorous snail Littorina littorea structures rocky intertidal communities through strong grazing pressure and is frequently parasitized by the digenean trematode Cryptocotyle lingua. We hypothesized that the effects of parasitism on host physiology would induce behavioral changes in L. littorea, which in turn would modulate L. littorea's influence on intertidal community composition. Specifically, we hypothesized that C. lingua …
Crystal Structure Of The Vibrio Cholerae Quorum-Sensing Regulatory Protein Hapr, Rukman S. De Silva, Gabriela Kovacikova, Wei Lin, Ronald K. Taylor, Karen Skorupski, F. Jon Kull
Crystal Structure Of The Vibrio Cholerae Quorum-Sensing Regulatory Protein Hapr, Rukman S. De Silva, Gabriela Kovacikova, Wei Lin, Ronald K. Taylor, Karen Skorupski, F. Jon Kull
Dartmouth Scholarship
Quorum sensing in Vibrio cholerae involves signaling between two-component sensor protein kinases and the response regulator LuxO to control the expression of the master regulator HapR. HapR, in turn, plays a central role in regulating a number of important processes, such as virulence gene expression and biofilm formation. We have determined the crystal structure of HapR to 2.2-Å resolution. Its structure reveals a dimeric, two-domain molecule with an all-helical structure that is strongly conserved with members of the TetR family of transcriptional regulators. The N-terminal DNA-binding domain contains a helix-turn-helix DNA-binding motif and alteration of certain residues in this domain …
Coordinated Regulation Of Myc Trans-Activation Targets By Polycomb And The Trithorax Group Protein Ash1, Julie M. Goodliffe, Michael D. Cole, Eric Wieschaus
Coordinated Regulation Of Myc Trans-Activation Targets By Polycomb And The Trithorax Group Protein Ash1, Julie M. Goodliffe, Michael D. Cole, Eric Wieschaus
Dartmouth Scholarship
The Myc oncoprotein is a transcriptional regulator whose function is essential for normal development. Myc is capable of binding to 10% of the mammalian genome, and it is unclear how a developing embryo controls the DNA binding of its abundant Myc proteins in order to avoid Myc's potential for inducing tumorigenesis.To identify chromatin binding proteins with a potential role in controlling Myc activity, we established a genetic assay for dMyc activity in Drosophila. We conducted a genome-wide screen using this assay, and identified the Trithorax Group protein Ash1 as a modifier of dMyc activity. Ash1 is a histone methyltransferase known …
Detecting Agency From The Biological Motion Of Veridical Vs Animated Agents, Raymond A. Mar, William M. Kelley, Todd F. Heatherton, C. Neil Macrae
Detecting Agency From The Biological Motion Of Veridical Vs Animated Agents, Raymond A. Mar, William M. Kelley, Todd F. Heatherton, C. Neil Macrae
Dartmouth Scholarship
The ability to detect agency is fundamental for understanding the social world. Underlying this capacity are neural circuits that respond to patterns of intentional biological motion in the superior temporal sulcus and temporoparietal junction. Here we show that the brain's blood oxygenation level dependent (BOLD) response to such motion is modulated by the representation of the actor. Dynamic social interactions were portrayed by either live-action agents or computer-animated agents, enacting the exact same patterns of biological motion. Using an event-related design, we found that the BOLD response associated with the perception and interpretation of agency was greater when identical physical …
Stoichiometric Controls Of Mercury Dilution By Growth, Roxanne Karimi, Celia Y. Chen, Paul C. Pickhardt, Nicholas S. Fisher, Carol L. Folt
Stoichiometric Controls Of Mercury Dilution By Growth, Roxanne Karimi, Celia Y. Chen, Paul C. Pickhardt, Nicholas S. Fisher, Carol L. Folt
Dartmouth Scholarship
Rapid growth could significantly reduce methylmercury (MeHg) concentrations in aquatic organisms by causing a greater than proportional gain in biomass relative to MeHg (somatic growth dilution). We hypothesized that rapid growth from the consumption of high-quality algae, defined by algal nutrient stoichiometry, reduces MeHg concentrations in zooplankton, a major source of MeHg for lake fish. Using a MeHg radiotracer, we measured changes in MeHg concentrations, growth and ingestion rates in juvenile Daphnia pulex fed either high (C:P = 139) or low-quality (C:P = 1317) algae (Ankistrodesmus falcatus) for 5 d. We estimated Daphnia steady-state MeHg concentrations, using a …
Changes In Nitrogen Cycling During The Past Century In A Northern Hardwood Forest, Kendra K. Mclauchlan, Joseph M. Craine, W. Wyatt Oswald, Peter R. Leavitt, Gene E. Likens
Changes In Nitrogen Cycling During The Past Century In A Northern Hardwood Forest, Kendra K. Mclauchlan, Joseph M. Craine, W. Wyatt Oswald, Peter R. Leavitt, Gene E. Likens
Dartmouth Scholarship
Nitrogen (N) availability, defined here as the supply of N to terrestrial plants and soil microorganisms relative to their N demands, limits the productivity of many temperate zone forests and in part determines ecosystem carbon (C) content. Despite multidecadal monitoring of N in streams, the long-term record of N availability in forests of the northeastern United States is largely unknown. Therefore, although these forests have been receiving anthropogenic N deposition for the past few decades, it is still uncertain whether terrestrial N availability has changed during this time and, subsequently, whether forest ecosystems have responded to increased N deposition. Here, …
Membrane Association And Multimerization Of Tcpt, The Cognate Atpase Ortholog Of The Vibrio Cholerae Toxin-Coregulated-Pilus Biogenesis Apparatus, Shital A. Tripathi, Ronald K. Taylor
Membrane Association And Multimerization Of Tcpt, The Cognate Atpase Ortholog Of The Vibrio Cholerae Toxin-Coregulated-Pilus Biogenesis Apparatus, Shital A. Tripathi, Ronald K. Taylor
Dartmouth Scholarship
The toxin-coregulated pilus (TCP) is one of the major virulence factors of Vibrio cholerae. Biogenesis of this type 4 pilus (Tfp) requires a number of structural components encoded by the tcp operon. TcpT, the cognate putative ATPase, is required for TCP biogenesis and all TCP-mediated functions. We studied the stability and localization of TcpT in cells containing in-frame deletions in each of the tcp genes. TcpT was detectable in each of the biogenesis mutants except the ΔtcpT strain. TcpT was localized to the inner membrane (IM) in a TcpR-dependent manner. TcpR is a predicted bitopic inner membrane protein …
Impact Of Minimum Winter Temperatures On The Population Dynamics Of Dendroctonus Frontalis, J. KhảI TrầN, Tiina Ylioja, Ronald F. Billings, Jacques Régnière, Matthew P. Ayres
Impact Of Minimum Winter Temperatures On The Population Dynamics Of Dendroctonus Frontalis, J. KhảI TrầN, Tiina Ylioja, Ronald F. Billings, Jacques Régnière, Matthew P. Ayres
Dartmouth Scholarship
Predicting population dynamics is a fundamental problem in applied ecology. Temperature is a potential driver of short-term population dynamics, and temperature data are widely available, but we generally lack validated models to predict dynamics based upon temperatures. A generalized approach involves estimating the temperatures experienced by a population, characterizing the demographic consequences of physiological responses to temperature, and testing for predicted effects on abundance. We employed this approach to test whether minimum winter temperatures are a meaningful driver of pestilence from Dendroctonus frontalis (the southern pine beetle) across the southeastern United States. A distance-weighted interpolation model provided good, spatially explicit, …
A 368-Base-Pair Cis-Acting Hwp1 Promoter Region, Hcr, Of Candida Albicans Confers Hypha-Specific Gene Regulation And Binds Architectural Transcription Factors Nhp6 And Gcf1p, Samin Kim, Michael J. Wolyniak, Janet F. Staab, Paula Sundstrom
A 368-Base-Pair Cis-Acting Hwp1 Promoter Region, Hcr, Of Candida Albicans Confers Hypha-Specific Gene Regulation And Binds Architectural Transcription Factors Nhp6 And Gcf1p, Samin Kim, Michael J. Wolyniak, Janet F. Staab, Paula Sundstrom
Dartmouth Scholarship
To elucidate the molecular mechanisms controlling the expression of the hypha-specific adhesin gene HWP1 of Candida albicans, its promoter was dissected and analyzed using a green fluorescent protein reporter gene. A 368-bp region, the HWP1 control region (HCR), was critical for activation under hypha-inducing conditions and conferred developmental regulation to a heterologous ENO1 promoter. A more distal region of the promoter served to amplify the level of promoter activation. Using gel mobility shift assays, a 249-bp subregion of HCR, HCRa, was found to bind at least four proteins from crude extracts of yeasts and hyphae with differing binding patterns dependent …