Life Sciences Commons^™

Free-Living Allen’S Hummingbirds (Selasphorus Sasin) Rarely Use Torpor While Nesting, Erich R. Eberts, Glenn J. Tattersall, Peter J. Auger, Maria Curley, Melissa I. Morado, Eric G. Strauss, Don Powers, Noemi C. Soveral, Bret W. Tobalske, Anusha Shankar

Faculty Publications - Department of Biological & Molecular Science

For reproducing animals, maintaining energy balance despite thermoregulatory challenges is important for surviving and successfully raising offspring. This is especially apparent in small endotherms that exhibit high mass-specific metabolic rates and live in unpredictable environments. Many of these animals use torpor, substantially reducing their metabolic rate and often body temperature to cope with high energetic demands during non-foraging periods. In birds, when the incubating parent uses torpor, the lowered temperatures that thermally sensitive offspring experience could delay development or increase mortality risk. We used thermal imaging to noninvasively explore how nesting female hummingbirds sustain their own energy balance while effectively …

Does Wing Use And Disuse Cause Behavioural And Musculoskeletal Changes In Domestic Fowl (Gallus Gallus Domesticus)?, Renée C. Garant, Bret W. Tobalske, Neila Ben Sassi, Nienke Van Staaveren, Dan Tulpan, Tina Widowski, Donald R. Powers, Alexandra Harlander-Matauschek

Faculty Publications - Department of Biological & Molecular Science

Domestic chickens may live in environments which restrict wing muscle usage. Notably, reduced wing activity and accompanying muscle weakness are hypothesized risk factors for keel bone fractures and deviations. We used radio-frequency identification (RFID) to measure duration spent at elevated resources (feeders, nest-boxes), ultrasonography to measure muscle thickness (breast and lower leg) changes, radiography and palpation to determine fractures and deviations, respectively, following no, partial (one-sided wing sling) and full (cage) immobilization in white- and brown-feathered birds. We hypothesized partially immobilized hens would reduce elevated resource usage and that both immobilization groups would show decreased pectoralis thickness (disuse) and increased …

Eye Lens Β-Crystallins Are Predicted By Native Ion Mobility-Mass Spectrometry And Computations To Form Compact Higher-Ordered Heterooligomers, Amber D. Rolland, Takumi Takata, Micah T. Donor, Kirsten J. Lampi, James S. Prell

Faculty Publications - Department of Biological & Molecular Science

Eye lens crystallin proteins maintain the refractive properties of the lens but are not replaced after denucleation. Rolland et al. use native ion mobility-mass spectrometry, kinetics experiments, and computations to reveal that b-crystallins form heterodimers. These likely assemble into compact heterooligomers that enable the very high protein concentrations found in lens tissue.

Protein Shape Sampled By Ion Mobility Mass Spectrometry Consistently Improves Protein Structure Prediction, Micah T. Donor, Sm Bargeen Alam Turzo, Justin T. Seffernick, Amber D. Rolland, Stein Heinze, James S. Prell, Vicki H. Wysocki, Steffen Lindert

Faculty Publications - Department of Biological & Molecular Science

Ion mobility (IM) mass spectrometry provides structural information about protein shape and size in the form of an orientationally-averaged collision cross-section (CCSIM). While IM data have been used with various computational methods, they have not yet been utilized to predict monomeric protein structure from sequence. Here, we show that IM data can significantly improve protein structure determination using the modelling suite Rosetta. We develop the Rosetta Projection Approximation using Rough Circular Shapes (PARCS) algorithm that allows for fast and accurate prediction of CCSIM from structure. Following successful testing of the PARCS algorithm, we use an integrative modelling approach to utilize …

Effects Of Clipping Of Flight Feathers On Resource Use In Gallus Gallus Domesticus, Renee Garant, Bret W. Tobalske, Neila Bensassi, Nienke Van Staaveren, Dan Tulpan, Tina Widowski, Donald R. Powers, Alexandra Harlander-Matauschek

Faculty Publications - Department of Biological & Molecular Science

Ground-dwelling species of birds, such as domestic chickens (Gallus gallus domesticus), experience difficulties sustaining flight due to high wing loading. This limited flight ability may be exacerbated by loss of flight feathers that is prevalent among egg-laying chickens. Despite this, chickens housed in aviary style systems need to use flight to access essential resources stacked in vertical tiers. To understand the impact of flight feather loss on chickens’ ability to access elevated resources, we clipped primary and secondary flight feathers for two hen strains (brown-feathered and white-feathered, n = 120), and recorded the time hens spent at elevated resources (feeders, …

Domestic Egg-Laying Hens, Gallus Gallus Domesticus, Do Not Modulate Flapping Flight Performance In Response To Wing Condition, Brianna M. León, Bret W. Tobalske, Neila Ben Sassi, Renée Garant, Donald R. Powers, Alexandra Harlander-Matauschek

Faculty Publications - Department of Biological & Molecular Science

Wild birds modulate wing and whole-body kinematics to adjust their flight patterns and trajectories when wing loading increases flight power requirements. Domestic chickens (Gallus gallus domesticus) in backyards and farms exhibit feather loss, naturally high wing loading, and limited flight capabilities. Yet, housing chickens in aviaries requires birds to navigate three-dimensional spaces to access resources. To understand the impact of feather loss on laying hens’ flight capabilities, we symmetrically clipped the primary and secondary feathers before measuring wing and whole-body kinematics during descent from a 1.5 m platform. We expected birds to compensate for increased wing loading by increasing wingbeat …

Regulation Of Kv11.1 Isoform Expression By Polyadenylate Binding Protein Nuclear 1, Matthew R. Stump, Rachel T. Nguyen, Rachel H. Drgastin, Delaney Search, Quiming Gong, Zhengfeng Zhou

Faculty Publications - Department of Biological & Molecular Science

The Kv11.1 voltage-gated potassium channel, encoded by the KCNH2 gene, conducts the rapidly activating delayed rectifier current in the heart. KCNH2 pre-mRNA undergoes alternative polyadenylation to generate two C-terminal Kv11.1 isoforms in the heart. Utilization of a poly(A) signal in exon 15 produces the full-length, functional Kv11.1a isoform, while intron 9 polyadenylation generates the C-terminally truncated, nonfunctional Kv11.1a-USO isoform. The relative expression of Kv11.1a and Kv11.1a-USO isoforms plays an important role in the regulation of Kv11.1 channel function. In this study, we tested the hypothesis that the RNA polyadenylate binding protein nuclear 1 (PABPN1) interacts with a unique 22 nt …

Measurement And Theory Of Gas-Phase Ion Mobility Shifts Resulting From Isotopomer Mass Distribution Changes, Christopher P. Harrilal, Viraj D. Gandhi, Gabe Nagy, Xi Chen, Michael G. Buchanan, Roza Wojcik, Christopher R. Conant, Micah T. Donor, Yehia M. Ibrahim, Sandilya V. B. Garimella, Richard D. Smith, Carlos Larriba-Andaluz

Faculty Publications - Department of Biological & Molecular Science

The unanticipated discovery of recent ultra-high-resolution ion mobility spectrometry (IMS) measurements revealing that isotopomers—compounds that differ only in the isotopic substitution sites—can be separated has raised questions as to the physical basis for their separation. A study comparing IMS separations for two isotopomer sets in conjunction with theory and simulations accounting for ion rotational effects provides the first-ever prediction of rotation-mediated shifts. The simulations produce observable mobility shifts due to differences in gas−ion collision frequency and translational-to-rotational energy transfer. These differences can be attributed to distinct changes in the moment of inertia and center of mass between isotopomers. The simulations …

Combined Effects Of Experimentally Elevated Cort And Predation Threat On Exploratory And Foraging Behavior Of Desmognathus Ochrophaeus, Aaron M. Sullivan, Ian E. Kratzer, Seanna C. Jobe, Jacquelyn L. Lewis

Faculty Publications - Department of Biological & Molecular Science

Amphibian responses to stress are generally mediated through glucocorticoids produced by the hypothalamic–pituitary–interrenal axis. Chronic elevation of glucocorticoids can result in delayed wound healing and growth, but less is known about its influence on behavioral responses to predators. We examined the effect of acute and chronic CORT elevation on exploratory and foraging behaviors of Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus) exposed to kairomones from a predatory snake. We established ‘No CORT,' ‘Acute CORT,' and ‘Chronic CORT’ conditions during an 18-d preparation phase by varying salamander exposure to an exogenous source of CORT (0.51 mg/mL) delivered via cutaneous patch. …

Lipid Head Group Adduction To Soluble Proteins Follows Gas-Phase Basicity Predictions: Dissociation Barriers And Charge Abstraction, Micah T. Donor, Jesse W. Wilson, Samantha O. Shepherd, James S. Prell

Faculty Publications - Department of Biological & Molecular Science

Native mass spectrometry analysis of membrane proteins has yielded many useful insights in recent years with respect to membrane protein-lipid interactions, including identifying specific interactions and even measuring binding affinities based on observed abundances of lipid-bound ions after collision-induced dissociation (CID). However, the behavior of non-covalent complexes subjected to extensive CID can in principle be affected by numerous factors related gas- subjected to extensive CID can in principle be affected by numerous factors related gas- subjected to extensive CID can in principle be affected by numerous factors related gas-subjected to extensive CID can in principle be affected by numerous factors …

Dynamic Time-Warping Correction For Shifts In Ultrahigh Resolving Power Ion Mobility Spectrometry And Structures For Lossless Ion Manipulations, Adam L. Hollerbach, Christopher R. Conant, Gabe Nagy, Matthew E. Monroe, Khushboo Gupta, Micah T. Donor, Cameron M. Giberson, Sandilya V. B. Garimella, Richard D. Smith, Yehia M. Ibrahim

Faculty Publications - Department of Biological & Molecular Science

Detection of arrival time shifts between ion mobility spectrometry (IMS) separations can limit achievable resolving power (Rp), particularly when multiple separations are summed or averaged, as commonly practiced in IMS. Such variations can be apparent in higher Rp measurements and are particularly evident in long path length traveling wave structures for lossless ion manipulations (SLIM) IMS due to their typically much longer separation times. Here, we explore data processing approaches employing single value alignment (SVA) and nonlinear dynamic time warping (DTW) to correct for variations between IMS separations, such as due to pressure fluctuations, to enable more effective spectrum summation …

What Forests Teach Us About Community, Paige E. Copenhaver-Parry

Faculty Publications - Department of Biological & Molecular Science

Each spring, I have the privilege of witnessing the miracle of new life as seeds that have buried themselves in the soil over the winter sprout roots, shed their papery coats, and stretch their bright green needles up toward the sun. My students and I spend weeks crawling across the forest floor – bellies, knees, and elbows scraping through the rich humus – as we identify, count, and measure hundreds of newly emerged conifer seedlings. Some of these seedlings will eventually grow into some of the largest trees in the world, but for now they stand scarcely two inches tall.

Taking Temperature With Leaves: A Semester-Long Structured- Inquiry Research Investigation For Undergraduate Plant Biology, Paige E. Copenhaver-Parry

Faculty Publications - Department of Biological & Molecular Science

Inquiry- and course-based research pedagogies have demonstrated effectiveness for preparing undergraduate biology students with authentic scientific skills and competencies, yet many students lack the experience to engage successfully in open-ended research activities without sufficient scaffolding and structure. Further, curricula for student-centered laboratory activities are lacking for several biological disciplines, including plant biology and botany. In this article, I describe a semester-long structured-inquiry research curriculum developed for a plant biology course taught to second-year biology students that integrates key elements of inquiry and discovery while providing a structured approach to gaining research skills. In the research project, students collect leaves from …

The Allometry Of Daily Energy Expenditure In Hummingbirds: An Energy Budget Approach, Anushu Shankar, Donald R. Powers, Liliana M. Dávalos, Catherine H. Graham

Faculty Publications - Department of Biological & Molecular Science

1. Within-clade allometric relationships represent standard laws of scaling between energy and size, and their outliers provide new avenues for physiological and ecological research. According to the metabolic-level boundaries hypothesis, metabolic rates as a function of mass are expected to scale closer to 0.67 when driven by surface-related processes (e.g. heat or water flux), while volume-related processes (e.g. activity) generate slopes closer to one.

2. In birds, daily energy expenditure (DEE) scales with body mass (M) in the relationship log (DEE)=2.35+0.68×log (M), consistent with surface-level processes driving the relationship. However, taxon-specific patterns differ from the scaling slope of all birds. …

Salamander Stress And Duress: The Relationship Between Cort, Autotomy And Regeneration, And Exploratory Behaviour, Aaron M. Sullivan, Jacquelyn L. Lewis

Faculty Publications - Department of Biological & Molecular Science

Responses to stress are generally mediated through the production of glucocorticoids by the hypothalamic-pituitary-adrenal (or -interrenal) axis. The prolonged production of stress hormones can contribute to delayed wound healing and growth, but little is known about their influence on regeneration following tail autotomy, or exploratory behaviour in autotomized individuals. Here we examined the relationship between stress, re-generation, and exploratory behaviour in Allegheny Mountain dusky salamanders (Desmognathus ochrophaeus) by manipulating corticosterone (CORT) levels via cutaneous patch. First, we measured tail regeneration in salamanders with elevated CORT for 13 weeks after the induction of tail autotomy. Test subjects received a weekly patch …

Evaluating Volatile Organic Compound Emissions From Cross-Laminated Timber Bonded With A Soy-Based Adhesive, Michael Yauk, Jason Stenson, Micah T. Donor, Kevin Van Den Wymelenberg

Faculty Publications - Department of Biological & Molecular Science

Volatile organic compound (VOC) emissions from indoor sources are large determinants of the indoor air quality (IAQ) and occupant health. Cross-laminated timber (CLT) is a panelized engineered wood product often left exposed as an interior surface finish. As a certified structural building product, CLT is currently exempt from meeting VOC emission limits for composite wood products and confirming emissions through California Department of Public Health (CDPH) Standard Method testing. In this study, small chamber testing was conducted to evaluate VOC emissions from three laboratory-produced CLT samples: One bonded with a new soy-based cold-set adhesive; a second bonded with a commercially …

Protonation Isomers Of Highly Charged Protein Ions Can Be Separated In Faims-Ms, J. Diana Zhang, Micah T. Donor, Amber D. Rolland, Michael G. Leeming, Huixin Wang, Adam J. Trevitt, K.M. Mohibul Kabir, James S. Prell, William A. Donald

Faculty Publications - Department of Biological & Molecular Science

High-field asymmetric waveform ion mobility spectrometry-mass spectrometry (FAIMS-MS) can resolve over an order of magnitude more conformers for a given protein ion than alternative methods. Such an expansion in separation space results, in part, from protein ions with masses of >29 kDa undergoing dipole alignment in the high electric field of FAIMS, and the resolution of ions that adopt pendular vs free rotor states. In this study, FAIMS-MS, collision-induced dissociation (CID), and travelling wave (TW) IMS-MS were used to investigate the pendular and free rotor states of protonated carbonic anhydrase II (CAII, 29 kDa). The electrospray ionization additive 1,2-butylene carbonate …

Increasing Collisional Activation Of Protein Complexes Using Smaller Aperture Source Sampling Cones On A Synapt Q-Im-Tof Instrument With A Stepwave Source, Jesse W. Wilson, Micah T. Donor, Samantha O. Shepherd, James S. Prell

Faculty Publications - Department of Biological & Molecular Science

Quadrupole-ion mobility-time-of-flight (Q-IM-TOF) mass spectrometers have revolutionized investigation of native biomolecular complexes. High pressures in the sources of these instruments aid transmission of protein complexes through damping of kinetic energy by collisional cooling. Since adducts are removed through collisional heating (declustering), excessive collisional cooling can prevent removal of non-specific adducts from protein ions, leading to inaccurate mass measurements, broad mass spectral peaks, and obfuscation of ligand binding. We show that reducing the source pressure using smaller aperture source sampling cones (SC) in a Waters Synapt G2-Si instrument increases protein ion heating by decreasing collisional cooling, providing a simple way to …

Rapid Determination Of Activation Energies For Gas-Phase Protein Unfolding And Dissociation In A Q-Im-Tof Mass Spectrometer, Micah T. Donor, Samantha O. Shepherd, James S. Prell

Faculty Publications - Department of Biological & Molecular Science

Ion mobility-mass spectrometry has emerged as a powerful tool for interrogating a wide variety of chemical systems. Collision-induced unfolding (CIU), typically performed in time-of-flight instruments, has been utilized to obtain valuable qualitative insight into protein structure and illuminate subtle differences between related species. CIU experiments can be performed relatively quickly, but unfolding energy information obtained from them has not yet been interpreted quantitatively. While several methods can determine quantitative dissociation energetics for small molecules, clusters, and peptides, these methods have rarely been applied to proteins, and never to study unfolding. Here, we present a method to rapidly determine activation energies …

Multi‐Scale Integration Of Tree Recruitment And Range Dynamics In A Changing Climate, Paige E. Copenhaver-Parry, Charles J. W. Carroll, Patrick H. Martin, Matthew V. Talluto

Faculty Publications - Department of Biological & Molecular Science

Aim: The rate and magnitude of climate‐induced tree range shifts may be influenced by range‐wide variation in recruitment, which acts as a bottleneck in tree range dynamics. Here, we compare range predictions made using standard species distribution models (SDMs) and an integrated metamodelling approach that assimilates data on adult occurrence, seedling recruitment dynamics, and seedling survival under both current and future climate, and evaluate the degree to which information provided by seedling data can improve predictions of range dynamics.

Location: The interior west region of the United States.

Time period: 1990–2015.

Major taxa studied: Five widespread conifer tree species.

Methods: …

Hummingbirds Budget Energy Flexibly In Response To Changing Resources, Anusha Shankar, Catherine H. Graham, Joseph R. Canepa, Susan M. Wethington, Don Powers

Faculty Publications - Department of Biological & Molecular Science

1. A key component of individual fitness is the ability to manage energy stores in response to variable resource availability, but because directly measuring energy budgets is difficult, daily energy management is rarely measured.
2. Hummingbirds' energy management is relatively simple to model compared to other endotherms because they have high mass‐specific metabolic rates and store little fat.
3. We determined which aspects of the hummingbird daily energy budget (i.e. thermoregulation, daytime activity costs, night‐time costs) change at the individual level in response to environmental variation.
4. We found that daily energy expenditure varied threefold in two populations of broad‐billed hummingbirds (Cynanthus latirostris …

Environmental Determinants Of Recruitment Success Of Subalpine Fir (Abies Lasiocarpa) In A Mixed-Conifer Forest, Elizah Z. Stephens, Christopher P. Murar, Daniel B. Tinker, Paige E. Copenhaver-Parry

Faculty Publications - Department of Biological & Molecular Science

Understanding the processes that underlie forest resilience is of increasing importance as climate change and shifting disturbance regimes continue to impact western forests. Forest research and management efforts within the low-diversity conifer forests of the U.S. Rocky Mountains have typically focused on relatively monotypic stands dominated by a single cohort, but mixed-conifer stands, such as those codominated by Abies lasiocarpa and Pinus contorta have been less widely studied. The presence of A. lasiocarpa may enhance resilience to fire- and mountain pine beetle–induced mortality and depends on successful A. lasiocarpa recruitment under a range of environmental conditions. The purpose of this …

Experimental And Theoretical Investigation Of Overall Energy Deposition In Surface-Induced Unfolding Of Protein Ions, Micah T. Donor, Austin M. Mroz, James S. Prell

Faculty Publications - Department of Biological & Molecular Science

Recent advances in native mass spectrometry have enabled its use to probe the structure of and interactions within biomolecular complexes. Surface-induced dissociation, in which inter- and intramolecular interactions are disrupted following an energetic ion-surface collision, is a method that can directly interrogate the topology of protein complexes. However, a quantitative relationship between the ion kinetic energy at the moment of surface collision and the internal energy deposited into the ion has not yet been established for proteins. The factors affecting energy deposition in surface-induced unfolding (SIU) of protein monomers were investigated and a calibration relating laboratory-frame kinetic energy to internal …

Regulation Of Kv11.1 Potassium Channel C-Terminal Isoform Expression By The Rna-Binding Proteins Hur And Hud, Qiuming Gong, Matthew R. Stump, Zhengfeng Zhou

Faculty Publications - Department of Biological & Molecular Science

The potassium voltage-gated channel subfamily H member 2 (KCNH2) gene encodes the Kv11.1 potassium channel, which conducts the rapidly activating delayed rectifier current in the heart. KCNH2 pre-mRNA undergoes alternative polyadenylation and forms a functional, full-length Kv11.1a isoform if exon 15 is polyadenylated or a nonfunctional, C-terminally truncated Kv11.1a-USO isoform if intron 9 is polyadenylated. The molecular mechanisms that regulate Kv11.1 isoform expression are poorly understood. In this study, using HEK293 cells and reporter gene expression, pulldown assays, and RNase protection assays, we identified the RNA-binding proteins Hu antigen R (HuR) and Hu antigen D (HuD) as regulators of Kv11.1 …

Rivoli's Hummingbird: Eugenes Fulgens, Donald R. Powers

Faculty Publications - Department of Biological & Molecular Science

Rivoli's Hummingbird was named in honor of the Duke of Rivoli when the species was described by René Lesson in 1829. Even when it became known that William Swainson had written an earlier description of this species in 1827, the common name Rivoli's Hummingbird remained until the early 1980s, when it was changed to Magnificent Hummingbird. In 2017, however, the name was restored to Rivoli's Hummingbird when the American Ornithological Society officially recognized Eugenes fulgens as a distinct species from E. spectabilis, the Talamanca Hummingbird, of the highlands of Costa Rica and western Panama.

Rivoli's Hummingbird is found from the …

Integrating Morphology And Kinematics In The Scaling Of Hummingbird Hovering Metabolic Rate And Efficiency, Derrick J. E. Groom, M. Cecilia B. Toledo, Donald R. Powers, Bret W. Tobalske, Kenneth C. Welch Jr.

Faculty Publications - Department of Biological & Molecular Science

Wing kinematics and morphology are influential upon the aerodynamics of flight. However, there is a lack of studies linking these variables to metabolic costs, particularly in the context of morphological adaptation to body size. Furthermore, the conversion efficiency from chemical energy into movement by the muscles (mechanochemical efficiency) scales with mass in terrestrial quadrupeds, but this scaling relationship has not been demonstrated within flying vertebrates. Positive scaling of efficiency with body size may reduce the metabolic costs of flight for relatively larger species. Here, we assembled a dataset of morphological, kinematic, and metabolic data on hovering hummingbirds to explore the …

Upregulation Of Functional Kv11.1a Isoform Expression By Modified U1 Small Nuclear Rna, Qiuming Gong, Matthew R. Stump, Zhengfeng Zhou

Faculty Publications - Department of Biological & Molecular Science

The KCNH2 or human ether-a go-go-related gene (hERG) encodes the Kv11.1 potassium channel that conducts the rapidly activating delayed rectifier potassium current in the heart. The expression of Kv11.1 C-terminal isoforms is directed by the alternative splicing and polyadenylation of intron 9. Splicing of intron 9 leads to the formation of a functional, full-length Kv11.1a isoform and polyadenylation of intron 9 results in the production of a non-functional, C-terminally truncated Kv11.1a-USO isoform. The relative expression of Kv11.1a and Kv11.1a-USO plays an important role in regulating Kv11.1 channel function. In the heart, only one-third of KCNH2 pre-mRNA is processed to Kv11.1a …

Energetic Consequences For A Northern, Range-Edge Lizard Population, Sean D. Powers, Matthew R. Mcternan, Donald R. Powers, Roger A. Anderson

Faculty Publications - Department of Biological & Molecular Science

Lizards at the northern, cool edge of their geographic range in the northern hemisphere should encounter environmental conditions that differ from those living near the core of their range. To better understand how modest climate differences affect lizard energetics, we compared daily feeding and metabolism rates of individual Sceloporus occidentalis in two populations during mid-summer. Chuckanut Beach (CB) was a cool, maritime climate in northern Washington State, and Sondino Ranch (SR) was a warmer, drier climate in southern, inland Washington. We found no difference between populations in daily energy expenditure (DEE), as calculated from doubly labeled water estimates. The CB …

Drosophila Exo70 Is Essential For Neurite Extension And Survival Under Thermal Stress, Alex Chun Koon, Zhefan Stephan Chen, Shaohong Peng, Joyce Man See Fung, Xiaoman Zhang, Kayly M. Lembke, Hoi Kin Chow, C. Andrew Frank, Liwen Jiang, Kwok-Fai Lau, Ho Yin Edwin Chan

Faculty Publications - Department of Biological & Molecular Science

The octomeric exocyst complex governs the final step of exocytosis in both plants and animals. Its roles, however, extend beyond exocytosis and include organelle biogenesis, ciliogenesis, cell migration, and cell growth. Exo70 is a conserved component of the exocyst whose function in Drosophila is unclear. In this study, we characterized two mutant alleles of Drosophila exo70. exo70 mutants exhibit reduced synaptic growth, locomotor activity, glutamate receptor density, and mEPSP amplitude. We found that presynaptic Exo70 is necessary for normal synaptic growth at the neuromuscular junction (NMJ). At the neuromuscular junction, exo70 genetically interacts with the small GTPase ralA to regulate …

Species Interactions Weakly Modify Climate-Induced Tree Co-Occurrence Patterns, Paige E. Copenhaver-Parry, David M. Bell

Faculty Publications - Department of Biological & Molecular Science

Aims: Species distributions are hypothesized to be underlain by a complex association of processes that span multiple spatial scales including biotic interactions, dispersal limitation, fine-scale resource gradients and climate. Species disequilibrium with climate may reflect the effects of non-climatic processes on species distributions, yet distribution models have rarely directly considered non-climatic processes. Here, we use a Joint Species Distribution Model (JSDM) to investigate the influence of non-climatic factors on species co-occurrence patterns and to directly quantify the relative influences of climate and alternative processes that may generate correlated responses in species distributions, such as species interactions, on tree co-occurrence patterns. …