Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Animals (3)
- Biological (3)
- Models (3)
- Climate change (2)
- Evolution (2)
-
- Extinction (2)
- Flowers (2)
- Genetic (2)
- Genetics (2)
- Molecular (2)
- Acclimatization (1)
- Alleles (1)
- Ancient (1)
- Arabidopsis (1)
- Arabidopsis proteins (1)
- Bahamas (1)
- Base sequence (1)
- Bees (1)
- Biology (1)
- Biology and life sciences (1)
- Biomarkers (1)
- Biomass (1)
- Blood pressure (1)
- Body mass index (1)
- Body temperature regulation (1)
- Calcitriol (1)
- Cell membrane (1)
- Cell polarity (1)
- Cells (1)
- Chemistry (1)
Articles 1 - 10 of 10
Full-Text Articles in Biology
Publication Trends In Model Organism Research, Michael Dietrich, Rachel Ankeny, Patrick Chen
Publication Trends In Model Organism Research, Michael Dietrich, Rachel Ankeny, Patrick Chen
Dartmouth Scholarship
In 1990, the National Institutes of Health (NIH) gave some organisms special status as designated model organisms. This article documents publication trends for these NIH-designated model organisms over the past 40 years. We find that being designated a model organism by the NIH does not guarantee an increasing publication trend. An analysis of model and nonmodel organisms included in GENETICS since 1960 does reveal a sharp decline in the number of publications using nonmodel organisms yet no decline in the overall species diversity. We suggest that organisms with successful publication records tend to share critical characteristics, such as being well …
Collapse Of An Ecological Network In Ancient Egypt, Justin Yeakel, Mathias Pires, Lars Rudolf, Nathaniel Dominy
Collapse Of An Ecological Network In Ancient Egypt, Justin Yeakel, Mathias Pires, Lars Rudolf, Nathaniel Dominy
Dartmouth Scholarship
The dynamics of ecosystem collapse are fundamental to determining how and why biological communities change through time, as well as the potential effects of extinctions on ecosystems. Here, we integrate depictions of mammals from Egyptian antiquity with direct lines of paleontological and archeological evidence to infer local extinctions and community dynamics over a 6,000-y span. The unprecedented temporal resolution of this dataset enables examination of how the tandem effects of human population growth and climate change can disrupt mammalian communities. We show that the extinctions of mammals in Egypt were nonrandom and that destabilizing changes in community composition coincided with …
Nectar Yeasts In The Tall Larkspur Delphinium Barbeyi (Ranunculaceae) And Effects On Components Of Pollinator Foraging Behavior, Robert N. Schaeffer, Cody R. Phillips, M. Catherine Duryea, Jonathan Andicoechea, Rebecca E. Irwin
Nectar Yeasts In The Tall Larkspur Delphinium Barbeyi (Ranunculaceae) And Effects On Components Of Pollinator Foraging Behavior, Robert N. Schaeffer, Cody R. Phillips, M. Catherine Duryea, Jonathan Andicoechea, Rebecca E. Irwin
Dartmouth Scholarship
Microorganisms frequently colonize the nectar of angiosperm species. Though capable of altering a suite of traits important for pollinator attraction, few studies exist that test the degree to which they mediate pollinator foraging behavior. The objective of our study was to fill this gap by assessing the abundance and diversity of yeasts associated with the perennial larkspur Delphinium barbeyi (Ranunculaceae) and testing whether their presence affected components of pollinator foraging behavior. Yeasts frequently colonized D. barbeyi nectar, populating 54–77% of flowers examined depending on site. Though common, the yeast community was species-poor, represented by a single species, Metschnikowia reukaufii. …
Natural Selection On Thermal Performance In A Novel Thermal Environment, Michael L. Logan, Robert M. Cox, Ryan Calsbeek
Natural Selection On Thermal Performance In A Novel Thermal Environment, Michael L. Logan, Robert M. Cox, Ryan Calsbeek
Dartmouth Scholarship
Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation …
A Distinct Tethering Step Is Vital For Vacuole Membrane Fusion, Michael Zick, William T. Wickner
A Distinct Tethering Step Is Vital For Vacuole Membrane Fusion, Michael Zick, William T. Wickner
Dartmouth Scholarship
Past experiments with reconstituted proteoliposomes, employing assays that infer membrane fusion from fluorescent lipid dequenching, have suggested that vacuolar SNAREs alone suffice to catalyze membrane fusion in vitro. While we could replicate these results, we detected very little fusion with the more rigorous assay of lumenal compartment mixing. Exploring the discrepancies between lipid-dequenching and content-mixing assays, we surprisingly found that the disposition of the fluorescent lipids with respect to SNAREs had a striking effect. Without other proteins, the association of SNAREs in trans causes lipid dequenching that cannot be ascribed to fusion or hemifusion. Tethering of the SNARE-bearing proteoliposomes was …
Phenotypic Robustness And The Assortativity Signature Of Human Transcription Factor Networks, Dov A. Pechenick, Joshua L. Payne, Jason H. Moore
Phenotypic Robustness And The Assortativity Signature Of Human Transcription Factor Networks, Dov A. Pechenick, Joshua L. Payne, Jason H. Moore
Dartmouth Scholarship
Many developmental, physiological, and behavioral processes depend on the precise expression of genes in space and time. Such spatiotemporal gene expression phenotypes arise from the binding of sequence-specific transcription factors (TFs) to DNA, and from the regulation of nearby genes that such binding causes. These nearby genes may themselves encode TFs, giving rise to a transcription factor network (TFN), wherein nodes represent TFs and directed edges denote regulatory interactions between TFs. Computational studies have linked several topological properties of TFNs - such as their degree distribution - with the robustness of a TFN's gene expression phenotype to genetic and environmental …
Recent Shifts In The Occurrence, Cause, And Magnitude Of Animal Mass Mortality Events, Samuel B. Fey, Adam M. Siepielski, Sébastien Nusslé, Kristina Cervantes-Yoshida, Jason L. Hwan, Eric R. Huber, Maxfield J. Fey, Alessandro Catenazzi, Stephanie M. Carlson
Recent Shifts In The Occurrence, Cause, And Magnitude Of Animal Mass Mortality Events, Samuel B. Fey, Adam M. Siepielski, Sébastien Nusslé, Kristina Cervantes-Yoshida, Jason L. Hwan, Eric R. Huber, Maxfield J. Fey, Alessandro Catenazzi, Stephanie M. Carlson
Dartmouth Scholarship
Mass mortality events (MMEs) are rapidly occurring catastrophic demographic events that punctuate background mortality levels. Individual MMEs are staggering in their observed magnitude: re- moving more than 90% of a population, resulting in the death of more than a billion individuals, or producing 700 million tons of dead biomass in a single event. Despite extensive documentation of individual MMEs, we have no understanding of the major features characterizing the occurrence and magnitude of MMEs, their causes, or trends through time. Thus, no framework exists for contextualizing MMEs in the wake of ongoing global and regional perturbations to natural systems. Here …
Variation In Arabidopsis Flowering Time Associated With Cis-Regulatory Variation In Constans, Ulises Rosas, Yu Mei, Qiguang Xie, Joshua A. Banta, Royce W. Zhou, Gabriela Seufferheld, Silvia Gerard, Lucy Chou, Naeha Bhambhra, Jennifer Deane Parks, Jonathan M. Flowers, C. Robertson Mcclung, Yoshie Hanzawa, Michael D. Purugganan
Variation In Arabidopsis Flowering Time Associated With Cis-Regulatory Variation In Constans, Ulises Rosas, Yu Mei, Qiguang Xie, Joshua A. Banta, Royce W. Zhou, Gabriela Seufferheld, Silvia Gerard, Lucy Chou, Naeha Bhambhra, Jennifer Deane Parks, Jonathan M. Flowers, C. Robertson Mcclung, Yoshie Hanzawa, Michael D. Purugganan
Dartmouth Scholarship
The onset of flowering, the change from vegetative to reproductive development, is a major life history transition in flowering plants. Recent work suggests that mutations in cis-regulatory mutations should play critical roles in the evolution of this (as well as other) important adaptive traits, but thus far there has been little evidence that directly links regulatory mutations to evolutionary change at the species level. While several genes have previously been shown to affect natural variation in flowering time in Arabidopsis thaliana, most either show protein-coding changes and/or are found at low frequency (<5%). Here we identify and characterize natural variation in the cis-regulatory sequence in the …
Interaction Between Allelic Variations In Vitamin D Receptor And Retinoid X Receptor Genes On Metabolic Traits, Karani S. Vimaleswaran, Alana Cavadino, Diane J. Berry, Massimo Mangino, Peter Andrews, Jason H. Moore
Interaction Between Allelic Variations In Vitamin D Receptor And Retinoid X Receptor Genes On Metabolic Traits, Karani S. Vimaleswaran, Alana Cavadino, Diane J. Berry, Massimo Mangino, Peter Andrews, Jason H. Moore
Dartmouth Scholarship
Low vitamin D status has been shown to be a risk factor for several metabolic traits such as obesity, diabetes and cardiovascular disease. The biological actions of 1, 25-dihydroxyvitamin D, are mediated through the vitamin D receptor (VDR), which heterodimerizes with retinoid X receptor, gamma (RXRG). Hence, we examined the potential interactions between the tagging polymorphisms in the VDR (22 tag SNPs) and RXRG (23 tag SNPs) genes on metabolic outcomes such as body mass index, waist circumference, waist-hip ratio (WHR), high- and low-density lipoprotein (LDL) cholesterols, serum triglycerides, systolic and diastolic blood pressures and glycated haemoglobin in the 1958 …
Septin Assemblies Form By Diffusion-Driven Annealing On Membranes, Andrew A. Bridges, Huaiying Zhang, Shalin B. Mehta, Patricia Occhipinti, Tomomi Tani, Amy S. Gladfelter
Septin Assemblies Form By Diffusion-Driven Annealing On Membranes, Andrew A. Bridges, Huaiying Zhang, Shalin B. Mehta, Patricia Occhipinti, Tomomi Tani, Amy S. Gladfelter
Dartmouth Scholarship
Septins assemble into filaments and higher-order structures that act as scaffolds for diverse cell functions including cytokinesis, cell polarity, and membrane remodeling. Despite their conserved role in cell organization, little is known about how septin filaments elongate and are knitted together into higher-order assemblies. Using fluorescence correlation spectroscopy, we determined that cytosolic septins are in small complexes, suggesting that septin filaments are not formed in the cytosol. When the plasma membrane of live cells is monitored by total internal reflection fluorescence microscopy, we see that septin complexes of variable size diffuse in two dimensions. Diffusing septin complexes collide and make …