UNDERGRADUATE RESEARCH GRANTS

Project Title: Effects of temperature and humidity on the metabolism of nectar in Aedes albopictus and Ae. aegypti mosquitoes

• GCC Faculty mentor: Dr. Chloé Lahondère

Mosquitoes transmit several pathogens to humans and other animals killing about a million people every year. If females need blood to produce eggs, both females and males feed on plant nectar which enhances their survival and longevity. For this project, we will focus on two invasive mosquito species, Aedes aegypti and Ae. albopictus. These mosquitoes are originally indigenous to the tropics but have now spread around the world (including the US). Global warming has been shown to increase the habitable range of these mosquitoes in part due to raising temperatures. As their geographical range expands it increases their threat to public health. Surprisingly, how environmental factors such as temperature and humidity, in combination with access to nectar sources, affect mosquito population dynamics remain unknown. To fill this knowledge gap, we will first conduct studies on laboratory strains of mosquitoes and quantify their metabolism and digestion on nectar under different environmental conditions using calorimetric assays. Then field work will be conducted in Virginia to assess sugar feeding prevalence in these invasive species. Altogether, these data will shed light on how mosquitoes are utilizing nectar in the field and will inform on the development of new traps to control mosquito populations.

Project Title: From water chemistry to growth: making sense of the abiotic world of frogs

• GCC Faculty mentor: Dr. Meryl Mims

Many organisms rely on environmental cues to signal when to grow and develop to maximize chances of survival. However, anthropogenic threats, such as climate change, habitat alteration, and water pollution, pose a challenge to many species as it alters their environment. In Spring 2019, we conducted an artificial pond experiment to explore the effects of water temperatures, increased drying rates, and the combination of both on wood frog, ​Lithobates sylvaticus, a​ nd spring peeper, ​Pseudacris crucifer ​tadpoles. We examined how these environmental changes – anticipated to be an effect of climate change – influenced tadpole growth and survival. Analyzing how temperature and drying influence water quality parameters such as pH, dissolved oxygen, temperature, and conductivity may also lead us to a deeper understanding of the mechanistic pathways through which these environmental changes influence tadpole growth and overall survival. This past semester, I examined the significant differences of these parameters between treatments; however, we have yet to analyze chlorophyll-a to determine how algae, the tadpoles food source, is affected. I propose to expand this project by extracting chlorophyll-a from algae samples collected during the experiment. Analyzing this information along with the other water chemistry parameters will provide a detailed understanding of the tadpoles’ abiotic environment under warming and drying conditions and how this ultimately affects their growth and survival.

Project Title: Wetlands in a Warming World: The Importance of Wetlands in Headwater Carbon Cycling

• GCC Faculty mentor: Dr. Erin Hotchkiss

Wetlands are productive ecosystems that play an important role in carbon cycling. However, wetland contributions to landscape CO2 and CH4 emissions are often overlooked and the role of wetlands in producing carbon emissions remains a critical gap in carbon budgets. To estimate current and future emissions from wetlands at Coweeta, NC and Jefferson National Forest, VA, I will measure CH4 and CO2 emitted from each wetland to the atmosphere and conduct laboratory warming experiments to calculate microbial organic carbon (OC) uptake and CO2 production. I will use a flux chamber attached to a portable greenhouse gas analyzer to get real-time estimates of CO2 and CH4 fluxes across each wetland. I will develop and test an improved flux chamber design to allow for more accurate and abundant flux measurements. To test how microbial uptake of OC (and subsequent CO2 and CH4 production) may change with increasing temperature, I will incubate filtered and microbially-inoculated wetland water at ambient and +3°C in triplicate bioassays with ambient and amended (+CNP) nutrients. I predict that increased temperature increases OC uptake and CH4 and CO2 production. This experiment will provide insight into the current and future role of wetlands in carbon cycling with changes in temperature.

Project Title: Development of Poison Ivy Clonal Lines Differentiated for High or Low Urushiol Levels: Genetic Resources for Ecological Studies in Urushiol Chemical Ecology

• GCC Faculty mentor: Dr. John Jelesko

Poison ivy seedlings grown in vitro produce markedly different steady state urushiol accumulation levels, apparently due to underlying genetic factors. I will leverage these findings to develop poison ivy clonal lines with varying urushiol levels. I have developed an experiment to germinate 50 poison ivy seeds collected from each of four states: Michigan, Iowa, Virginia, and Texas. I will harvest the first true leaf pair from each seedling and assay total-urushiol levels by Gas Chromatograph-Mass Spectrometry. From these results, I will choose from each accession the four plants with the highest urushiol levels and the four with the lowest urushiol levels. This subset of plants from each state will be transplanted to pots with potting mix and grown in a Washington Street greenhouse with supplemental lighting and automated watering. There, they will produce stolons with genetically-identical daughter plants. These clones will again be assayed for total urushiol levels to confirm the stability of the high and low urushiol accumulation traits. The long term goal of this experiment is to transfer these plants to Kentland Farm this summer and quantify whether urushiol actually reduces herbivory by extant native fauna.

Project Title: In Cold Blood: Understanding The Role Mosquitoes Play in Pathogen Transmission to Frogs

• GCC Faculty mentor: Dr. Chloé Lahondère

Amphibian extinction is now happening at an unprecedented rate in part due to alteration of local ecosystems, climate change and diseases. Among diseases, emerging viral pathogens, Ranaviruses, as well as Batrachochytrium dendrobatidis, a fungus that infects the skin, are greatly affecting amphibian populations, most notably frogs. This combination of habitat loss, rising temperatures and diseases has made this issue complicated and multifaceted. This project focuses on the role that Culex territans, a mosquito that feeds primarily on cold-blooded animals including frogs and snakes, plays in disease transmission in amphibians in Virginia. Cx. territans is a known pathogenic transmission vector, capable of spreading parasitic trypanosomes to various species of amphibians. We hypothesized that Cx. territans may also be capable of spreading the aforementioned viral and fungal diseases. To test for this hypothesis, we will screen blood fed Cx. territans from local areas for pathogens during plaque assays and PCR with specific primers. Data emerging from this project will help us better understand the complex dynamics seen between amphibian extinction, transmission of pathogens, and host-vector relationships.

Project Title: CRISPR Genome Editing of Hairy Roots to Identify and Confirm Poison Ivy Urushiol Biosynthetic Genes

• GCC Faculty mentor: Dr. John Jelesko

Urushiol is produced in poison ivy and causes allergic dermatitis in humans. Poison ivy is projected to become more allergenic with higher atmospheric CO2 levels associated with climate change. Urushiol’s primary ecological purpose is currently unknown because it is uninvestigated. Moreover, none of the urushiol biosynthetic genes and enzymes have been previously validated. A previous Jelesko Lab GCC UG Research Awardee Nye Lott successfully developed an Agrobacterium rhizogenes-based poison ivy stable transformation system to produce transgenic poison ivy hairy roots containing CRISPR-Cas9 gene editing plasmids that target poison ivy PolyKetide Sythase-like (PKS-like) genes proposed to be involved in the first step in urushiol biosynthesis. My research project will follow on Nye’s A. rhizogenes strains containing PKS-specific CRISPR-Cas9 T-DNA binary plasmids to produce transgenic poison ivy hairy root lines with mutated PKS genes. The resulting transgenic hairy root lines will be evaluated for urushiol levels using GC-MS. If they show a decrease in urushiol levels, then the hairy roots lines will be sequenced for mutations in the targeted PKS genes. Hairy root lines with mutated specific PKS genes that result in dramatically less urushiol levels will be strong evidence that a specific PKS gene is necessary for urushiol biosynthesis.

Project Title: Identification of Urushiol Biosynthetic Genes by Differential Gene Expression in Tissues with Different Urushiol Accumulation Levels

• GCC Faculty mentor: Dr. John Jelesko

Poison Ivy plants produce urushiol, the compound that causes the characteristic allergic contact dermatitis symptoms in humans. The main goal of this project is to identify genes that are likely responsible for producing urushiol in poison ivy. In order to accomplish this goal, we will use a comparative transcriptomics approach between poison ivy tissues that accumulate markedly different amounts of urushiol. Preliminary work by a former GCC Undergraduate Awardee Nye Lott, suggested that poison ivy drupes accumulated between 8 to 45-fold more urushiol than the adjacent leaves. The lab has 20 matched pairs of poison ivy drupes with adjacent leaf material available for my experiments. I will extract total RNA from five pairs of matched poison ivy drupes and their corresponding adjacent leaves showing maximum differential urushiol accumulation levels. These 10 total RNA samples will be sent to NovoGene for library preparation and Illumina NextGen sequencing (RNA-seq). The collaborating Haak laboratory will perform the RNAseq analyses using their unpublished draft poison ivy whole genome to quantify and identify differentially expressed genes. I will subsequently sort through the differentially expressed poison ivy genes to identify specific predicted enzymatic activities involved in urushiol biosynthesis. This informatic resource will be used for many studies.

Project Title: The Effect of pH and symbiont density on outcomes in a cleaning symbiosis

• GCC Faculty mentor: Dr. Bryan Brown

For over 20 years, the Brown Lab has studied the context-dependent cleaning symbiosis between crayfish and ecosymbiotic branchiobdellidan annelids. These worms act as cleaners for the crayfish, increasing the hosts’ fitness. However, the benefits from the symbiosis for the host are context dependent, and can shift from mutualism to parasitism under some conditions including high symbiont densities. However, what isn’t currently known is whether the symbiotic outcome will change under conditions of host stress. Given that changes in pH are common stressors in aquatic systems, it makes sense to examine how the outcomes of the symbiosis will change with this change in context. I will use varying levels of the branchiobdellidan, Cambarincola ingens crossed with a pH gradient in an aquarium experiment using previously successful methodologies. Response variables will be growth and survivorship of the host crayfish. We have already run preliminary versions of this experiment and produced results that suggest that intermediate densities of C. ingens will increase growth and survivorship at pH levels that depart from known norms. Lessons learned from that preliminary experiment will increase our probability of success with the proposed experiment.

Project Title: Equilin does not affect thyroid hormone signaling in the developing Xenopus laevis tadpole brain

• Robert Bass, Junior majoring in Experimental Neuroscience
• GCC Faculty mentor: Christopher Thompson

The Thompson Lab is in the process of evaluating putative thyroid hormone disrupting compounds identified by the Tox21 and ToxCast federal programs. One putative disruptor is equilin, a naturally occurring estrogen used in the menopause drug Premarin. Robert is the primary researcher for this project, assessing the effects of equilin on thyroid hormone sensitive changes in the developing brains of tadpoles. Robert is leading every stage of the experiment, including design, treatment, euthanasia, staining, imaging, RNA extraction and analysis, and final quantification and figure preparation. Robert will be presenting date previously collected at the annual Society of Toxicology meeting in March. His plan for spring semester is to analyze the effects of equilin on expression of thyroid hormone and estrogen sensitive genes in the developing tadpole brain. The GCC fellowship will provide Robert with the resources he needs to complete the remaining experiments. When those data are in place, he will be writing the paper for this project and will be lead author – a huge accomplishment for any undergraduate!

Project Title: Quantifying Nucleic Acid Association with Nanoparticles

• Ethan Boeding, Junior majoring in Nanoscience
• GCC Faculty mentor: Peter Vikesland

Ethan is been working in the Vikesland Lab on a project to examine whether micro- and nano-plastics can serve as vehicles for the dissemination of antibiotic resistance genes. This project brings together two generally unrelated topics that the Vikesland research group investigates: nanomaterial fate in environmental systems and the dissemination of antimicrobial resistance. Nanoplastic wastes potentially originate from consumer products such as personal cleaning and cosmetic products as well as weathering of larger plastics. These nanoscale plastic particles can potentially interact with their surrounding environment when they are discharged to wastewater treatment facilities and ultimately to water bodies. In wastewater treatment, there is potential for the creation of recombinant genetic material that propagates antimicrobial resistance (AMR). The results from this project will provide a greater understanding of the adsorption behavior of DNA onto these nanoparticles in the environment.

Project Title: Assessing the Historical Burden of Mange in Wildlife

• Rosalie Gude, Freshman majoring in Animal Science
• Joy Flowers, Sophomore majoring Wildlife Conservation
• Caitlin Storment, Junior majoring in Wildlife Conservation
• GCC Faculty mentor: Luis Escobar

Mange is a devastating disease caused by Sarcoptes scabei in wildlife that results in severe itching, scabbing, and hair loss. This can ultimately lead to death due to lack of warmth in the winter or due to secondary infections, which may contribute to population decline and cascade effects in the food web. The Escobar laboratory has noticed an increase of mange in various mammal species and geographic regions. The first part of this undergraduate research will focus on assessing mange lesions of museum specimens of wild carnivores from the Atlantic-belt region of the US; the second part will involve surveying bear hunters to pinpoint a timeline of when mange started to become perceived. The results will help to determine whether mange is actually increasing in local wild carnivore populations or if researchers are just more aware of the problem and thus noticing more cases. By visiting museums and taking surveys of hunters, the students will be able to look into the past to determine if mange was detectable in the study region decades ago. This study will quantitatively support the idea that mange is an emergent wildlife disease of concern.

Project Title: Effects of the environmental temperature on Aedes albopictus mosquitoes’ activity and feeding

• Cameron Hart, Sophomore majoring in Biochemistry
• GCC Faculty mentor: Chloé Lahondère

For this project, Cameron will focus on Ae. albopictus, the Asian tiger mosquito that is invasive in the Southern US, including Virginia and is expected to move North in the context of global warming. This species is present in Blacksburg and greatly affects its citizens each year because of its aggressive biting behavior. As this species can vector several diseases including Zika, it is important to better understand its biology and how this species can adapt to its new environment. The aim of Cameron’s project is thus to get a better understanding of the impact of the environmental temperature on the mosquito activity, including feeding. By comparing the behavior of a well-established lab strain with mosquitoes collected locally around Blacksburg under different thermal conditions, Cameron will be able to evince any possible adaptations (e.g. cold hardiness, thermal stress resistance) that allow this invasive species to rapidly adapt and extend its geographical distribution.

Project Title: Genetic analysis of an isolated Arizona Treefrog population to uncover dispersal and connectivity patterns

• Jacob Helmann, Junior majoring in Biology
• GCC Faculty mentor: Meryl Mims

Jacob will work with the Mims Lab to evaluate the consistency of population genetic analyses in which peripheral populations are included or omitted from analyses of genetic structure and connectivity, thus addressing a knowledge gap for the strengths and potential biases of using this tool for species with uncertain distributional limits. The Huachuca Mountains and Canelo Hills of Arizona are home to isolated populations of the Arizona Treefrog, Hyla Wrightorum, a species of conservation concern. These isolated populations are morphologically and genetically unique. In 2017, DNA was collected from individuals in a previously unsampled population, discovered only in 2014, that is geographically isolated from other previously studied populations. Jacob will work to genotype and analyze the new DNA samples to determine similarity and connectivity to other populations. The goal of his research is to provide insights into the dispersal dynamics of this species, directly informing the management of a species of conservation concern in a region undergoing significant influences of global change, including fire, invasive species and hydrologic change.

Project Title: Drivers and Patterns of Dissolved Organic Matter Cycling in Drinking Water Reservoirs

• Dexter Howard, Junior majoring in Water: Resources, Policy and Management
• GCC Faculty mentor: Cayelan Carey

During the past two years, Dexter has served a critical role in leading both field and laboratory research as part of the Carey Lab’s water quality monitoring of Roanoke’s drinking water reservoirs. This research is conducted in collaboration with the labs of Drs. Maddy Schreiber and John Little as part of the interdisciplinary Reservoir Science Group at Virginia Tech. In the summer of 2018, the Western Virginia Water Authority (WVWA) shut down the water treatment plant for their focal study reservoir because of an exceedance in disinfection byproducts (DBPs). DBPs are thought to be due to organic carbon (OC) increases in the water column, but the drivers of variability in OC in our reservoirs remain unknown. Dexter collected weekly samples as part of his research grant awarded by the GCC in 2018; data which suggest that OC may be related to oxygen and temperature conditions, but more highly-resolved (sub-hourly) samples are needed to determine the drivers at the time scales of manager decision-making. To fulfill this need, a sensor has been deployed in the reservoir that monitors OC at the 10-minute scale. Dexter will use this data study the magnitude and drivers of variability of OC, and will present his results to the WVWA and at the annual Virginia Lake and Watershed Association conference in spring 2020. Dexter will be also be mentored by Carey Lab member and IGC Fellow, Mary Lofton.

Project Title: The phenology and interactions in the reproduction of Bluehead Chub (Nocomis leptocephalus) and Central Stoneroller (Campostoma anomalum) and their nest associates

• Emma Hultin, Senior majoring in Biology
• GCC Faculty mentor: Emmanuel Frimpong

The primary aim of Emma’s study is to clarify life history strategies of bluehead chub and stoneroller and their nest associate species, by defining the phenology (timing) and location (nest-host choice) of spawning. Phenology will be determined by 1) observing relative species abundance on nests during breeding season using several seasons of underwater video footage, and 2) genetic identification of eggs sampled from nests. Previous studies have identified species from over 1,000 eggs from chub nests. This study will sample eggs from only stoneroller nests to complement. The eggs identified will also be compared with water temperature (measured with data loggers) and photoperiod to determine the range of environmental conditions needed for each species to spawn. Sampling will be done at two locations on Toms Creek in Blacksburg.

Project Title: Destabilization of Permafrost Soil Carbon with Climate Change

• Annie Ligush, Sophomore majoring in Environmental Resources Management
• GCC Faculty mentor: Brian Strahm

Soils represent the largest actively cycling pool of carbon on the planet, greater than the sum of the atmosphere and all terrestrial vegetation. The susceptibility of this carbon reservoir to decomposition under climate change (i.e., increased temperature and altered moisture) poses a significant feedback to the climate system. This is particularly true of the carbon-rich permafrost soils of northern latitudes. Annie’s study will utilize an existing NSF-sponsored project focused on the mechanisms of carbon stabilization across a host of National Ecological Observatory Network (NEON) sites to focus specifically on three observatories in Alaska. Upper and lower soil mesocosms will be incubated for one-year in a 2 (temperature) x 3 (moisture) factorial design to determine the potential for future climate alteration to affect the carbon balance of these systems.

Project Title: Vegetation choice for nest-site selection of female Song Sparrows among rural and urban habitats

• Courtney Linkous, Senior majoring in Wildlife Conservation
• GCC Faculty mentor: Kendra Sewall

Vegetation choice plays an important role in nest-site selection as it may determine whether a nest becomes predated or makes it to full term. The goals of Courtney’s research project is to compare the plant species that are selected for nest-sites by Song Sparrow breeding pairs from rural and urban habitats and assess how the following factors affect birds’ survival and success in producing offspring by observing the following:

1. Vegetation chosen for nest sites

2. Nest height and depth within the vegetation (when possible)

3. Rates of predation and success (number of young fledged from full term nests)

For the study, she will use previously collected data points for nests from the 2017 and 2018 breeding seasons to examine the impact of the height and depth of nest placement within the vegetation on nest success. In spring of 2019, she will add to this data set by locating and monitoring the success of nestlings as a function of the nest site and vegetation. Collectively, this information will allow her to determine how plant selection influences nest survival. This information could be used by managers and developers to create urban and suburban areas that are more hospitable to wildlife.

Project Title:  The effects of spatial and temporal hydrologic variation on microbial carbon-substrate metabolic diversity and greenhouse gas emissions

• Jonathon Monroe, Junior majoring in Biological Sciences
• GCC Faculty mentor: Erin Hotchkiss

Global climate change increases variability in weather, results in surface water wetting/drying, and alters connectivity among ecosystems. These variations cause rapidly changing interactions within ecosystems that result in microbially-enhanced greenhouse gas emissions. The role of microbes in carbon cycle responses to changing climate and hydrology is still poorly quantified. To better predict the effects of climate change, changing microbial metabolic diversity over space and time must be linked with environmental changes. For the project, Jonathon will collaborate with members of the Hotchkiss lab, including IGC Fellow Kristen Bretz, to quantify the phenology of different carbon metabolism strategies in sites along the Poverty Creek stream network. His proposed project will address critical unknowns needed to advance our understanding of the role of microbes in predicted global change scenarios, such as ‘how are microbes responding to changing hydrology in stream networks that are wetting and drying more frequently with environmental change? and what are the consequences for carbon cycling and greenhouse gas emissions?’.

Project Title: Reconstituted Mining Effluent Induces Programmed Cell Death in the Developing Brain of Wild-Caught Wood Frog Tadpoles

• Hannah Sturgeon, Junior majoring in Cognitive and Behavioral Neuroscience
• GCC Faculty mentor: Christopher Thompson

Over the past year, Hannah has been working on a project studying the effects of mining effluent on brain development in wood frog tadpoles. She used immunostaining to analyze neurogenesis, to help better understand the rate of development. The data from last year’s project indicated that the wood frog brain may in fact regress in size at some of the highest concentrations of mining effluent. This suggests that there may be an increase in programmed cell death. With this grant award, Hannah will repeat the treatment, working with Dr. Sara Sweeten in the Department of Fish & Wildlife Conservation, but this time pick several additional time points and perform immunostaining for activated caspase-3 and H2AX, two markers of programmed cell death. In addition, they have recently perfected a clearing method that allows them to image the entire brain. She will create a 3D model of these brains and quantify changes in brain anatomy.