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Full-Text Articles in Life Sciences

Presence Of The Cyanotoxin Microcystin In Arctic Lakes Of Southwestern Greenland, Jessica Trout-Haney, Zachary Wood, Kathryn Cottingham Aug 2016

Presence Of The Cyanotoxin Microcystin In Arctic Lakes Of Southwestern Greenland, Jessica Trout-Haney, Zachary Wood, Kathryn Cottingham

Dartmouth Scholarship

Cyanobacteria and their toxins have received significant attention in eutrophic temperate and tropical systems where conspicuous blooms of certain planktonic taxa release toxins into fresh water, threatening its potability and safe use for recreation. Although toxigenic cyanobacteria are not confined to high nutrient environments, bloom-forming species, or planktonic taxa, these other situations are studied les often studied. For example, toxin production in picoplankton and benthic cyanobacteria—the predominant photoautotrophs found in polar lakes—is poorly understood. We quantified the occurrence of microcystin (MC, a hepatotoxic cyanotoxin) across 18 Arctic lakes in southwestern Greenland. All of the focal lakes contained detectable levels of …


The Importance Of Ambient Temperature To Growth And The Induction Of Flowering, C. R. Mcclung, Ping Lou, Victor Hermand, Jin A. Kim Aug 2016

The Importance Of Ambient Temperature To Growth And The Induction Of Flowering, C. R. Mcclung, Ping Lou, Victor Hermand, Jin A. Kim

Dartmouth Scholarship

Plant development is exquisitely sensitive to the environment. Light quantity, quality, and duration (photoperiod) have profound effects on vegetative morphology and flowering time. Recent studies have demonstrated that ambient temperature is a similarly potent stimulus influencing morphology and flowering. In Arabidopsis, ambient temperatures that are high, but not so high as to induce a heat stress response, confer morphological changes that resemble the shade avoidance syndrome. Similarly, these high but not stressful temperatures can accelerate flowering under short day conditions as effectively as exposure to long days. Photoperiodic flowering entails a series of external coincidences, in which environmental cycles of …


Belowground Rhizomes In Paleosols: The Hidden Half Of An Early Devonian Vascular Plant, Jinzhuang Xue, Zhenzhen Deng, Pu Huang, Kangjun Huang, Michael J. Benton, Ying Cui Aug 2016

Belowground Rhizomes In Paleosols: The Hidden Half Of An Early Devonian Vascular Plant, Jinzhuang Xue, Zhenzhen Deng, Pu Huang, Kangjun Huang, Michael J. Benton, Ying Cui

Dartmouth Scholarship

The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant−soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils …


Building From The Hiv Response Toward Universal Health Coverage, Jonathon Jay, Kent Buse, Marielle Hart, Robert Marten, Scott Kellerman, Morolake Odetoyinbo, Jonathan D. Quick, Timothy Evans, Peter Piot, Mark Dybul, Agnes Binagwaho Aug 2016

Building From The Hiv Response Toward Universal Health Coverage, Jonathon Jay, Kent Buse, Marielle Hart, Robert Marten, Scott Kellerman, Morolake Odetoyinbo, Jonathan D. Quick, Timothy Evans, Peter Piot, Mark Dybul, Agnes Binagwaho

Dartmouth Scholarship

Universal health coverage (UHC) has gained prominence as a global health priority. The UHC movement aims to increase access to quality, needed health services while reducing financial hardship from health spending, particularly in low- and middle- income countries.
As a policy agenda, UHC has been identified primarily with prepayment and risk-pool- ing programs. While financing policies provide important benefits, increasing access to health services will require broader reforms.
For lessons, the UHC movement should look to the global HIV response, which has confronted many of the same barriers to access in weak health systems. Considerable success on HIV has resulted …


Itar: A Web Server For Identifying Target Genes Of Transcription Factors Using Chip-Seq Or Chip-Chip Data, Chia-Chun Yang, Erik H. Andrews, Min-Hsuan Chen, Wan-Yu Wang Aug 2016

Itar: A Web Server For Identifying Target Genes Of Transcription Factors Using Chip-Seq Or Chip-Chip Data, Chia-Chun Yang, Erik H. Andrews, Min-Hsuan Chen, Wan-Yu Wang

Dartmouth Scholarship

Chromatin immunoprecipitation followed by massively parallel DNA sequencing (ChIP-seq) or microarray hybridization (ChIP-chip) has been widely used to determine the genomic occupation of transcription factors (TFs). We have previously developed a probabilistic method, called TIP (Target Identification from Profiles), to identify TF target genes using ChIP-seq/ChIP-chip data. To achieve high specificity, TIP applies a conservative method to estimate significance of target genes, with the trade-off being a relatively low sensitivity of target gene identification compared to other methods. Additionally, TIP’s output does not render binding-peak locations or intensity, information highly useful for visualization and general experimental biological use, while the …


Field Estimates Of Parentage Reveal Sexually Antagonistic Selection On Body Size In A Population Of Anolis Lizards, Mary C. Duryea, Patrick Bergeron, Zachary Clare-Salzler, Ryan Calsbeek Aug 2016

Field Estimates Of Parentage Reveal Sexually Antagonistic Selection On Body Size In A Population Of Anolis Lizards, Mary C. Duryea, Patrick Bergeron, Zachary Clare-Salzler, Ryan Calsbeek

Dartmouth Scholarship

Sexual dimorphism evolves when selection favors different phenotypic optima between the sexes. Such sexually antagonistic selection creates intralocus sexual conflict when traits are genetically correlated between the sexes and have sex‐specific optima. Brown anoles are highly sexually dimorphic: Males are on average 30% longer than females and 150% heavier in our study population. Viability selection on body size is known to be sexually antagonistic, and directional selection favors large male size whereas stabilizing selection constrains females to remain small. We build on previous studies of viability selection by measuring sexually antagonistic selection using reproductive components of fitness over three generations …


Individual Differences In Response Of Dorsomedial Prefrontal Cortex Predict Daily Social Behavior, Katherine E. Powers, Robert S. Chavez, Todd F. Heatherton Jul 2016

Individual Differences In Response Of Dorsomedial Prefrontal Cortex Predict Daily Social Behavior, Katherine E. Powers, Robert S. Chavez, Todd F. Heatherton

Dartmouth Scholarship

The capacity to accurately infer the thoughts and intentions of other people is critical for effective social interaction, and neural activity in dorsomedial prefrontal cortex (dmPFC) has long been linked with the extent to which people engage in mental state attribution. In this study, we combined functional neuroimaging and experience sampling methodologies to test the predictive value of this neural response for daily social behaviors. We found that individuals who displayed greater activity in dmPFC when viewing social scenes spent more time around other people on a daily basis. These findings suggest a specific role for the neural mechanisms that …


A Face Versus Non-Face Context Influences Amygdala Responses To Masked Fearful Eye Whites, M. Justin Kim, Kimberly M. Solomon, Maital Neta, F. Caroline Davis, Jonathan A. Oler, Emily C. Mazzulla, Paul J. Whalen Jul 2016

A Face Versus Non-Face Context Influences Amygdala Responses To Masked Fearful Eye Whites, M. Justin Kim, Kimberly M. Solomon, Maital Neta, F. Caroline Davis, Jonathan A. Oler, Emily C. Mazzulla, Paul J. Whalen

Dartmouth Scholarship

The structure of the mask stimulus is crucial in backward masking studies and we recently demonstrated such an effect when masking faces. Specifically, we showed that activity of the amygdala is increased to fearful facial expressions masked with neutral faces and decreased to fearful expressions masked with a pattern mask—but critically both masked conditions discriminated fearful expressions from happy expressions. Given this finding, we sought to test whether masked fearful eye whites would produce a similar profile of amygdala response in a face vs non-face context. During functional magnetic resonance imaging scanning sessions, 30 participants viewed fearful or happy eye …


A Heavy Metal P-Type Atpase Oshma4 Prevents Copper Accumulation In Rice Grain, Xin-Yuan Huang, Fenglin Deng, Naoki Yamaji, Shannon R.M. Pinson, Miho Fujii-Kashino, John Danku, Alex Douglas, Mary Lou Guerinot, David Salt, Jian Feng Ma Jul 2016

A Heavy Metal P-Type Atpase Oshma4 Prevents Copper Accumulation In Rice Grain, Xin-Yuan Huang, Fenglin Deng, Naoki Yamaji, Shannon R.M. Pinson, Miho Fujii-Kashino, John Danku, Alex Douglas, Mary Lou Guerinot, David Salt, Jian Feng Ma

Dartmouth Scholarship

Rice is a major source of calories and mineral nutrients for over half the world's human population. However, little is known in rice about the genetic basis of variation in accumulation of copper (Cu), an essential but potentially toxic nutrient. Here we identify OsHMA4 as the likely causal gene of a quantitative trait locus controlling Cu accumulation in rice grain. We provide evidence that OsHMA4 functions to sequester Cu into root vacuoles, limiting Cu accumulation in the grain. The difference in grain Cu accumulation is most likely attributed to a single amino acid substitution that leads to different OsHMA4 transport …


A New Method For Ecoacoustics? Toward The Extraction And Evaluation Of Ecologically-Meaningful Soundscape Components Using Sparse Coding Methods, Alice Eldridge, Michael Casey, Paola Moscoso, Mika Peck Jun 2016

A New Method For Ecoacoustics? Toward The Extraction And Evaluation Of Ecologically-Meaningful Soundscape Components Using Sparse Coding Methods, Alice Eldridge, Michael Casey, Paola Moscoso, Mika Peck

Dartmouth Scholarship

Passive acoustic monitoring is emerging as a promising non-invasive proxy for ecological complexity with potential as a tool for remote assessment and monitoring (Sueur & Farina, 2015). Rather than attempting to recognise species-specific calls, either manually or automatically, there is a growing interest in evaluating the global acoustic environment. Positioned within the conceptual framework of ecoacoustics, a growing number of indices have been proposed which aim to capture community- level dynamics by (e.g., Pieretti, Farina & Morri, 2011; Farina, 2014; Sueur et al.,2008b) by providing statistical summaries of the frequency or time domain signal. Although promising, the ecological relevance and …


Microrna Mir-155 Is Necessary For Efficient Gammaherpesvirus Reactivation From Latency, But Not For Establishment Of Latency, Rebecca L. Crepeau, Peisheng Zhang, Edward J. Usherwood Jun 2016

Microrna Mir-155 Is Necessary For Efficient Gammaherpesvirus Reactivation From Latency, But Not For Establishment Of Latency, Rebecca L. Crepeau, Peisheng Zhang, Edward J. Usherwood

Dartmouth Scholarship

MicroRNA-155 (miR-155) has been shown to play significant roles in the immune response, including in the formation of germinal centers (GC) and the development and maturation of T follicular helper (Tfh) cells. There is in vitro evidence to support a critical role for cellular miR-155 and viral miR-155 homologs in the establishment of gammaherpesvirus latency in B cells. We sought to determine the contribution of miR-155 to the establishment and maintenance of latency in vivousing murine gammaherpesvirus (MHV-68) infection. MHV-68-infected mice deficient in miR-155 exhibited decreases in GC B cells and Tfh cells. However, the frequencies of spleen cells …


Alcohol Discrimination And Preferences In Two Species Of Nectar-Feeding Primate, Samuel R. Gochman, Michael B. Brown, Nathaniel J. Dominy Jun 2016

Alcohol Discrimination And Preferences In Two Species Of Nectar-Feeding Primate, Samuel R. Gochman, Michael B. Brown, Nathaniel J. Dominy

Dartmouth Scholarship

Recent reports suggest that dietary ethanol, or alcohol, is a supplemental source of calories for some primates. For example, slow lorises (Nycticebus coucang) consume fermented nectars with a mean alcohol concentration of 0.6% (range: 0.0–3.8%). A similar behaviour is hypothesized for aye-ayes (Daubentonia madagascariensis) based on a single point mutation (A294V) in the gene that encodes alcohol dehydrogenase class IV (ADH4), the first enzyme to catabolize alcohol during digestion. The mutation increases catalytic efficiency 40-fold and may confer a selective advantage to aye-ayes that consume the nectar of Ravenala madagascariensis. It is uncertain, however, whether alcohol exists in this nectar …


The Brain Imaging Data Structure, A Format For Organizing And Describing Outputs Of Neuroimaging Experiments, Krzysztof Gorgolewski, Tibor Auer, Vince Calhoun, R Cameron Craddock, Samir Das, Eugene Duff, Guillaume Flandin, Tristan Glatard, Yaroslav Halchenko Jun 2016

The Brain Imaging Data Structure, A Format For Organizing And Describing Outputs Of Neuroimaging Experiments, Krzysztof Gorgolewski, Tibor Auer, Vince Calhoun, R Cameron Craddock, Samir Das, Eugene Duff, Guillaume Flandin, Tristan Glatard, Yaroslav Halchenko

Dartmouth Scholarship

The development of magnetic resonance imaging (MRI) techniques has defined modern neuroimaging. Since its inception, tens of thousands of studies using techniques such as functional MRI and diffusion weighted imaging have allowed for the non-invasive study of the brain. Despite the fact that MRI is routinely used to obtain data for neuroscience research, there has been no widely adopted standard for organizing and describing the data collected in an imaging experiment. This renders sharing and reusing data (within or between labs) difficult if not impossible and unnecessarily complicates the application of automatic pipelines and quality assurance protocols. To solve this …


Effect Of A Ropy Exopolysaccharide-Producing Bifidobacterium Animalis Subsp. Lactis Strain Orally Administered On Dss-Induced Colitis Mice Model, Claudio Hidalgo-Cantabrana, Francesca Algieri, Alba Rodriguez-Nogales, Teresa Vezza, Pablo Martínez-Camblor Jun 2016

Effect Of A Ropy Exopolysaccharide-Producing Bifidobacterium Animalis Subsp. Lactis Strain Orally Administered On Dss-Induced Colitis Mice Model, Claudio Hidalgo-Cantabrana, Francesca Algieri, Alba Rodriguez-Nogales, Teresa Vezza, Pablo Martínez-Camblor

Dartmouth Scholarship

Exopolysaccharide (EPS)-producing bifidobacteria, particularly Bifidobacterium animalis subsp. lactis strains, are used in the functional food industry as promising probiotics with purported beneficial effects. We used three isogenic strains of B. animalis subsp. lactis, with different EPS producing phenotypes (mucoid-ropy and non-ropy), in order to determine their capability to survive the murine gastrointestinal tract transit, as well as to evaluate their role in improving clinical outcomes in a chemically-induced colitis model. The three strains were able to survive in the intestinal tract of C57BL/6J mice during the course of the intervention study. Furthermore, the disease activity index (DAI) of the animal …


Depression In Visual Impairment Trial (Depvit): A Randomized Clinical Trial Of Depression Treatments In People With Low Vision, Claire L. Nollett, Nathan Bray, Catey Bunce, Robin J. Casten, Rhiannon T. Edwards, Mark T. Hegel, Sarah Janikoun, Sandra E. Jumbe, Barbara Ryan, Julia Shearn Jun 2016

Depression In Visual Impairment Trial (Depvit): A Randomized Clinical Trial Of Depression Treatments In People With Low Vision, Claire L. Nollett, Nathan Bray, Catey Bunce, Robin J. Casten, Rhiannon T. Edwards, Mark T. Hegel, Sarah Janikoun, Sandra E. Jumbe, Barbara Ryan, Julia Shearn

Dartmouth Scholarship

Purpose: The purpose of this study was to compare two interventions for depression, problem solving treatment (PST) and referral to the patient's physician, with a waiting-list control group in people with sight loss and depressive symptoms.

Methods: This was an assessor-masked, exploratory, multicenter, randomized clinical trial, with concurrent economic analysis. Of 1008 consecutive attendees at 14 low-vision rehabilitation centers in Britain, 43% (n = 430) screened positive for depressive symptoms on the Geriatric Depression Scale and 85 of these attendees participated in the trial. Eligible participants were randomized in the ratio 1:1:1 to PST, referral to their physician, or …


The Pseudomonas Aeruginosa Efflux Pump Mexghi-Opmd Transports A Natural Phenazine That Controls Gene Expression And Biofilm Development, Hassan Sakhtah, Leslie Koyama, Yihan Zhang, Diana K. Morales, Blanche Fields, Alexa Price-Whelan, Deborah Hogan Jun 2016

The Pseudomonas Aeruginosa Efflux Pump Mexghi-Opmd Transports A Natural Phenazine That Controls Gene Expression And Biofilm Development, Hassan Sakhtah, Leslie Koyama, Yihan Zhang, Diana K. Morales, Blanche Fields, Alexa Price-Whelan, Deborah Hogan

Dartmouth Scholarship

Redox-cycling compounds, including endogenously produced phenazine antibiotics, induce expression of the efflux pump MexGHI-OpmD in the opportunistic pathogen Pseudomonas aeruginosa Previous studies of P. aeruginosa virulence, physiology, and biofilm development have focused on the blue phenazine pyocyanin and the yellow phenazine-1-carboxylic acid (PCA). In P. aeruginosa phenazine biosynthesis, conversion of PCA to pyocyanin is presumed to proceed through the intermediate 5-methylphenazine-1-carboxylate (5-Me-PCA), a reactive compound that has eluded detection in most laboratory samples. Here, we apply electrochemical methods to directly detect 5-Me-PCA and find that it is transported by MexGHI-OpmD in P. aeruginosa strain PA14 planktonic and biofilm cells. We …


Flow-Dependent Myosin Recruitment During Drosophila Cellularization Requires Zygotic Dunk Activity, Bing He, Adam Martin, Eric Wieschaus May 2016

Flow-Dependent Myosin Recruitment During Drosophila Cellularization Requires Zygotic Dunk Activity, Bing He, Adam Martin, Eric Wieschaus

Dartmouth Scholarship

Actomyosin contractility underlies force generation in morphogenesis ranging from cytokinesis to epithelial extension or invagination. In Drosophila, the cleavage of the syncytial blastoderm is initiated by an actomyosin network at the base of membrane furrows that invaginate from the surface of the embryo. It remains unclear how this network forms and how it affects tissue mechanics. Here, we show that during Drosophila cleavage, myosin recruitment to the cleavage furrows proceeds in temporally distinct phases of tension-driven cortical flow and direct recruitment, regulated by different zygotic genes. We identify the gene dunk, which we show is transiently transcribed when cellularization starts …


Nonnative Forest Insects And Pathogens In The United States: Impacts And Policy Options, Gary M. Lovett, Marissa Weiss, Andrew M. Liebhold, Thomas P. Holmes, Brian Leung, Kathy F. Lambert, David A. Orwig, Faith T. Campbell, Jonathan Rosenthal, Deborah G. Mccullough, Radka Wildova, Matthew P. Ayres May 2016

Nonnative Forest Insects And Pathogens In The United States: Impacts And Policy Options, Gary M. Lovett, Marissa Weiss, Andrew M. Liebhold, Thomas P. Holmes, Brian Leung, Kathy F. Lambert, David A. Orwig, Faith T. Campbell, Jonathan Rosenthal, Deborah G. Mccullough, Radka Wildova, Matthew P. Ayres

Dartmouth Scholarship

We review and synthesize information on invasions of nonnative forest insects and diseases in the United States, including their ecological and economic impacts, pathways of arrival, distribution within the United States, and policy options for reducing future invasions. Nonnative insects have accumulated in United States forests at a rate of ~2.5 per yr over the last 150 yr. Currently the two major pathways of introduction are importation of live plants and wood packing material such as pallets and crates. Introduced insects and diseases occur in forests and cities throughout the United States, and the problem is particularly severe in the …


Acth Prevents Deficits In Fear Extinction Associated With Early Life Seizures, Andrew T. Massey, David K. Lerner, Gregory L. Holmes, Rod C. Scott, Amanda Hernan May 2016

Acth Prevents Deficits In Fear Extinction Associated With Early Life Seizures, Andrew T. Massey, David K. Lerner, Gregory L. Holmes, Rod C. Scott, Amanda Hernan

Dartmouth Scholarship

Objective: Early life seizures (ELS) are often associated with cognitive and psychiatric comorbidities that are detrimental to quality of life. In a rat model of ELS, we explored long-term cognitive outcomes in adult rats. Using ACTH, an endogeneous HPA-axis hormone given to children with severe epilepsy, we sought to prevent cognitive deficits. Through comparisons with dexamethasone, we sought to dissociate the corticosteroid effects of ACTH from other potential mechanisms of action.

Results: Although rats with a history of ELS were able to acquire a conditioned fear learning paradigm and controls, these rats had significant deficits in their ability to extinguish …


Protein-Directed Self-Assembly Of A Fullerene Crystal, Kook-Han Kim, Dong-Kyun Ko, Yong-Tae Kim, Nam Hyeong Kim, Jaydeep Paul, Shao-Qing Zhang, Christopher B. Murray, Rudresh Acharya, William F. Degrado, Yong Ho Kim, Gevorg Grigoryan Apr 2016

Protein-Directed Self-Assembly Of A Fullerene Crystal, Kook-Han Kim, Dong-Kyun Ko, Yong-Tae Kim, Nam Hyeong Kim, Jaydeep Paul, Shao-Qing Zhang, Christopher B. Murray, Rudresh Acharya, William F. Degrado, Yong Ho Kim, Gevorg Grigoryan

Dartmouth Scholarship

Learning to engineer self-assembly would enable the precise organization of molecules by design to create matter with tailored properties. Here we demonstrate that proteins can direct the self-assembly of buckminsterfullerene (C 60) into ordered superstructures. A previously engineered tetrameric helical bundle binds C 60 in solution, rendering it water soluble. Two tetramers associate with one C 60, promoting further organization revealed in a 1.67-Å crystal structure. Fullerene groups occupy periodic lattice sites, sandwiched between two Tyr residues from adjacent tetramers. Strikingly, the assembly exhibits high charge conductance, whereas both the protein-alone crystal and amorphous C 60 are electrically insulating. The …


Elevational Variation In Body-Temperature Response To Immune Challenge In A Lizard, Francisco Javier Zamora-Camacho, Senda Reguera, Gregorio Moreno-Rueda Apr 2016

Elevational Variation In Body-Temperature Response To Immune Challenge In A Lizard, Francisco Javier Zamora-Camacho, Senda Reguera, Gregorio Moreno-Rueda

Dartmouth Scholarship

Immunocompetence benefits animal fitness by combating pathogens, but also entails some costs. One of its main components is fever, which in ectotherms involves two main types of costs: energy expenditure and predation risk. Whenever those costs of fever outweigh its benefits, ectotherms are expected not to develop fever, or even to show hypothermia, reducing costs of thermoregulation and diverting the energy saved to other components of the immune system. Environmental thermal quality, and therefore the thermoregulation cost/benefit balance, varies geographically. Hence, we hypothesize that, in alpine habitats, immune-challenged ectotherms should show no thermal response, given that (1) hypothermia would be …


Detecting Gene-Gene Interactions Using A Permutation-Based Random Forest Method, Jing Li, James D. Malley, Angeline S. Andrew, Margaret R. Karagas, Jason H. Moore Apr 2016

Detecting Gene-Gene Interactions Using A Permutation-Based Random Forest Method, Jing Li, James D. Malley, Angeline S. Andrew, Margaret R. Karagas, Jason H. Moore

Dartmouth Scholarship

Identifying gene-gene interactions is essential to understand disease susceptibility and to detect genetic architectures underlying complex diseases. Here, we aimed at developing a permutation-based methodology relying on a machine learning method, random forest (RF), to detect gene-gene interactions. Our approach called permuted random forest (pRF) which identified the top interacting single nucleotide polymorphism (SNP) pairs by estimating how much the power of a random forest classification model is influenced by removing pairwise interactions.


Cosmomvpa: Multi-Modal Multivariate Pattern Analysis Of Neuroimaging Data In Matlab/Gnu Octave, Nikolaas N. Oosterhof, Andrew C. Connolly, James V. Haxby Apr 2016

Cosmomvpa: Multi-Modal Multivariate Pattern Analysis Of Neuroimaging Data In Matlab/Gnu Octave, Nikolaas N. Oosterhof, Andrew C. Connolly, James V. Haxby

Dartmouth Scholarship

Recent years have seen an increase in the popularity of multivariate pattern (MVP) analysis of functional magnetic resonance (fMRI) data, and, to a much lesser extent, magneto- and electro-encephalography (M/EEG) data. We present CoSMoMVPA, a lightweight MVPA (MVP analysis) toolbox implemented in the intersection of the Matlab and GNU Octave languages, that treats both fMRI and M/EEG data as first-class citizens. CoSMoMVPA supports all state-of-the-art MVP analysis techniques, including searchlight analyses, classification, correlations, representational similarity analysis, and the time generalization method. These can be used to address both data-driven and hypothesis-driven questions about neural organization and representations, both within and …


Micron-Scale Plasma Membrane Curvature Is Recognized By The Septin Cytoskeleton, Andrew A. Bridges, Maximilian S. Jentzsch, Patrick W. Oakes, Patricia Occhipinti, Amy S. Gladfelter Apr 2016

Micron-Scale Plasma Membrane Curvature Is Recognized By The Septin Cytoskeleton, Andrew A. Bridges, Maximilian S. Jentzsch, Patrick W. Oakes, Patricia Occhipinti, Amy S. Gladfelter

Dartmouth Scholarship

Cells change shape in response to diverse environmental and developmental conditions, creating topologies with micron-scale features. Although individual proteins can sense nanometer-scale membrane curvature, it is unclear if a cell could also use nanometer-scale components to sense micron-scale contours, such as the cytokinetic furrow and base of neuronal branches. Septins are filament-forming proteins that serve as signaling platforms and are frequently associated with areas of the plasma membrane where there is micron-scale curvature, including the cytokinetic furrow and the base of cell protrusions. We report here that fungal and human septins are able to distinguish between different degrees of micron-scale …


Horizontal Gene Acquisitions, Mobile Element Proliferation, And Genome Decay In The Host-Restricted Plant Pathogen Erwinia Tracheiphila, Lori R. Shapiro, Erin D. Scully, Timothy J. Straub, Jihye Park, Andrew G. Stephenson, Gwyn A. Beattie, Mark L. Gleason, Roberto Kolter, Miguel C. Coelho, Consuelo M. De Moraes, Mark C. Mescher, Olga Zhaxybayeva Mar 2016

Horizontal Gene Acquisitions, Mobile Element Proliferation, And Genome Decay In The Host-Restricted Plant Pathogen Erwinia Tracheiphila, Lori R. Shapiro, Erin D. Scully, Timothy J. Straub, Jihye Park, Andrew G. Stephenson, Gwyn A. Beattie, Mark L. Gleason, Roberto Kolter, Miguel C. Coelho, Consuelo M. De Moraes, Mark C. Mescher, Olga Zhaxybayeva

Dartmouth Scholarship

Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains of the cucurbit bacterial wilt pathogen Erwinia tracheiphila (Enterobacteriaceae) isolated from infected squash plants in New York, Pennsylvania, Kentucky, and Michigan. These genomes exhibit a high proportion of recent horizontal gene acquisitions, invasion and remarkable amplification of mobile genetic elements, and pseudogenization of approximately 20% of the coding sequences. These genome attributes indicate that E. tracheiphila recently emerged as a …


Where Are You Looking? Pseudogaze In Afterimages, Daw-An Wu, Patrick Cavanagh Mar 2016

Where Are You Looking? Pseudogaze In Afterimages, Daw-An Wu, Patrick Cavanagh

Dartmouth Scholarship

How do we know where we are looking? A frequent assumption is that the subjective experience of our direction of gaze is assigned to the location in the world that falls on our fovea. However, we find that observers can shift their subjective direction of gaze among different nonfoveal points in an afterimage. Observers were asked to look directly at different corners of a diamond-shaped afterimage. When the requested corner was 3.5° in the periphery, the observer often reported that the image moved away in the direction of the attempted gaze shift. However, when the corner was at 1.75° eccentricity, …


Fastpop: A Rapid Principal Component Derived Method To Infer Intercontinental Ancestry Using Genetic Data, Yafang Li, Jinyoung Byun, Guoshuai Cai, Xiangjun Xiao, Younghun Han, Olivier Cornelis, James E. Dinulos, Joe Dennis, Douglas Easton, Ivan Gorlov, Michael F. Seldin, Christopher I. Amos Mar 2016

Fastpop: A Rapid Principal Component Derived Method To Infer Intercontinental Ancestry Using Genetic Data, Yafang Li, Jinyoung Byun, Guoshuai Cai, Xiangjun Xiao, Younghun Han, Olivier Cornelis, James E. Dinulos, Joe Dennis, Douglas Easton, Ivan Gorlov, Michael F. Seldin, Christopher I. Amos

Dartmouth Scholarship

Identifying subpopulations within a study and inferring intercontinental ancestry of the samples are important steps in genome wide association studies. Two software packages are widely used in analysis of substructure: Structure and Eigenstrat. Structure assigns each individual to a population by using a Bayesian method with multiple tuning parameters. It requires considerable computational time when dealing with thousands of samples and lacks the ability to create scores that could be used as covariates. Eigenstrat uses a principal component analysis method to model all sources of sampling variation. However, it does not readily provide information directly relevant to ancestral origin; the …


The Adp-Ribose Polymerase Tankyrase Regulates Adult Intestinal Stem Cell Proliferation During Homeostasis In Drosophila, Zhenghan Wang, Ai Tian, Hassina Benchabane, Ofelia Tacchelly-Benites, Eungi Yang, Hisashi Nojima, Yashi Ahmed Mar 2016

The Adp-Ribose Polymerase Tankyrase Regulates Adult Intestinal Stem Cell Proliferation During Homeostasis In Drosophila, Zhenghan Wang, Ai Tian, Hassina Benchabane, Ofelia Tacchelly-Benites, Eungi Yang, Hisashi Nojima, Yashi Ahmed

Dartmouth Scholarship

Wnt/β-catenin signaling controls intestinal stem cell (ISC) proliferation, and is aberrantly activated in colorectal cancer. Inhibitors of the ADP-ribose polymerase Tankyrase (Tnks) have become lead therapeutic candidates for Wnt-driven cancers, following the recent discovery that Tnks targets Axin, a negative regulator of Wnt signaling, for proteolysis. Initial reports indicated that Tnks is important for Wnt pathway activation in cultured human cell lines. However, the requirement for Tnks in physiological settings has been less clear, as subsequent studies in mice, fish and flies suggested that Tnks was either entirely dispensable for Wnt-dependent processes in vivo, or alternatively, had tissue-specific roles. Here, …


The Fast-Evolving Phy-2 Gene Modulates Sexual Development In Response To Light In The Model Fungus Neurospora Crassa, Zheng Wang, Ning Li, Jigang Li, Jay C. Dunlap, Frances Trail, Jeffrey P. Townsend Mar 2016

The Fast-Evolving Phy-2 Gene Modulates Sexual Development In Response To Light In The Model Fungus Neurospora Crassa, Zheng Wang, Ning Li, Jigang Li, Jay C. Dunlap, Frances Trail, Jeffrey P. Townsend

Dartmouth Scholarship

Rapid responses to changes in incident light are critical to the guidance of behavior and development in most species. Phytochrome light receptors in particular play key roles in bacterial physiology and plant development, but their functions and regulation are less well understood in fungi. Nevertheless, genome-wide expression measurements provide key information that can guide experiments that reveal how genes respond to environmental signals and clarify their role in development. We performed functional genomic and phenotypic analyses of the two phytochromes in Neurospora crassa, a fungal model adapted to a postfire environment that experiences dramatically variable light conditions. Expression of phy-1 …


Data Publication With The Structural Biology Data Grid Supports Live Analysis, Peter A. Meyer, Stephanie Socias, Jason Key, Elizabeth Ransey, Emily C. Tjon, Alejandro Buschiazzo, Ming Lei, Chris Botka, James Withrow, David Neau, Kanagalaghatta Rajashankar, Karen S. Anderson, Chung-I Chang, Walter J. Chazin, Kevin D. Corbett, Michael S. Cosgrove, Sean Crosson, Sirano Dhe-Paganon, Enrico Di Cera, Catherine L. Drennan, Michael J. Eck, Brandt F. Eichman, Qing R. Fan, Adrian R. Ferre-D’Amare, J. Christopher Fromme, K. Christopher Garcia, Rachelle Gaudet, Peng Gong, Stephen C. Harrison, Ekaterina E. Heldwein, Zongchao Jia, Robert J. Keenan, Andrew C. Kruse, Marc Kvansaku, Jason S. Mclellan Mar 2016

Data Publication With The Structural Biology Data Grid Supports Live Analysis, Peter A. Meyer, Stephanie Socias, Jason Key, Elizabeth Ransey, Emily C. Tjon, Alejandro Buschiazzo, Ming Lei, Chris Botka, James Withrow, David Neau, Kanagalaghatta Rajashankar, Karen S. Anderson, Chung-I Chang, Walter J. Chazin, Kevin D. Corbett, Michael S. Cosgrove, Sean Crosson, Sirano Dhe-Paganon, Enrico Di Cera, Catherine L. Drennan, Michael J. Eck, Brandt F. Eichman, Qing R. Fan, Adrian R. Ferre-D’Amare, J. Christopher Fromme, K. Christopher Garcia, Rachelle Gaudet, Peng Gong, Stephen C. Harrison, Ekaterina E. Heldwein, Zongchao Jia, Robert J. Keenan, Andrew C. Kruse, Marc Kvansaku, Jason S. Mclellan

Dartmouth Scholarship

Access to experimental X-ray diffraction image data is fundamental for validation and reproduction of macromolecular models and indispensable for development of structural biology processing methods. Here, we established a diffraction data publication and dissemination system, Structural Biology Data Grid (SBDG; data.sbgrid.org), to preserve primary experimental data sets that support scientific publications. Data sets are accessible to researchers through a community driven data grid, which facilitates global data access. Our analysis of a pilot collection of crystallographic data sets demonstrates that the information archived by SBDG is sufficient to reprocess data to statistics that meet or exceed the quality of the …