The projects available for Cascade Scholars are described below. Projects are organized alphabetically by the mentor's last name and by department. Remember: on the application form, you will be asked to rank your top three projects and to explain your interest in each.
Current research in our lab focuses on how to make polymers that can degrade in response to a specific trigger. These materials may have applications in areas such as disease diagnostics, targeted drug delivery, and consumer packaging. This summer's projects will focus on synthesis of a monomer library that we will use to construct these degradable polymers. Students will learn the standard techniques of organic synthesis. Graduates of the Getzler lab pursue medicine (~40%), graduate degrees (~40%, including pharmacy, biology, chemistry, public health), and other areas (~20%).
Course requirements: two semesters of chemistry lecture and chemistry lab
Consider the salt and water balance challenges faced by a mosquito during its short lifecycle. Aquatic larvae live in freshwater and face osmotic water influx and diffusive salt loss. In contrast, terrestrial adults lose water by evaporation. Female mosquitoes confront a particular challenge after a blood meal — they must rapidly excrete a bolus of salt and water approximately equal to their pre-meal body mass. My research group studies the membrane transport proteins that allow mosquitoes and other insects to deal with these diverse challenges. These proteins also have roles in the nervous system because they influence the excitability of neurons.
We currently study a group of sodium dependent cation-chloride cotransporters (CCCs) from the yellow fever mosquito Aedes aegypti. These proteins carry salt across cell membranes, thus contributing to salt secretion or absorption. We have identified three genes that code for these proteins in mosquitoes. Two are only distantly related to the CCCs of vertebrate animals. We hypothesize that these proteins have evolved different roles to meet the diverse salt and water balance challenges in larval and adult insects. Moreover, we hypothesize that they are involved in modulating behaviors such as those associated with circadian rhythms.
Research students in my group use a variety of approaches, ranging from measurements of cation levels in insect blood and urine to molecular characterization of gene expression patterns. In addition to working with mosquitoes, we also use the fruit fly Drosophila melanogaster because it is a well-established model system. A Cascade Scholar who joins my research group will work collaboratively with other students on projects that combine physiological and molecular approaches. Example projects include 1) using antibodies to localize CCCs in larval and adult mosquito tissues and 2) evaluating function of fruit fly renal tubules after knock down of CCC expression.
Course requirements: Biology 109-110
Our lab investigates the molecular mechanisms underlying the regenerative abilities of the annelid worm Lumbriculus variegatus. When bisected, anterior ends of Lumbriculus re-grow new tails and posterior ends re-grow new heads. We are currently investigating the role of Hox genes and telomerase in this regeneration. Hox genes are transcription factors that provide positional information along the anterior-posterior axis and their expression in adult organisms may help maintain positional information needed for regeneration. Regeneration requires cell proliferation and thus DNA replication. During DNA replication, the ends of linear chromosomes (telomeres) erode, ultimately leading to cell senescence. Telomere shortening can be avoided through the actions of telomerase and thus telomerase may be a key enzyme in the regenerative process. To uncover the roles of Hox genes and telomerase, we are currently determining their expression levels in intact and regenerating worms with qRT-PCR. In the future we want to use gene knock-down approaches to determine the necessity of hox genes and telomerase for proper regeneration. In addition to learning techniques, the Cascade student will gain experience in lab notebook keeping, unpacking research articles, troubleshooting experiments and collaborating with other researchers.
Course requirements: Biology 116
Many organisms synchronize their sexual maturity and/or reproduction with favorable climatic conditions, which increases the odds of producing successful progeny. Plants, in particular, make use of environmental cues, such as day-length and temperature, to gauge the optimal time of year to initiate the formation of the reproductive structures that produce gametes — a process termed reproductive development. While the genetic mechanisms that regulate reproductive development in response to seasonal cues are largely conserved among flowering plants (Angiosperms), it is not known how their distant relatives, the first plants to come on land, use environmental cues to signal the onset of reproduction. Mosses (Bryophytes), are among these early land plant lineages and can thus aid in answering this question. Specifically, the moss Physcomitrella patens is a genetically tractable model species with an increasingly sophisticated set of community resources, including a sequenced reference genome and well-established protocols for transformation and the creation of targeted gene knockouts. Importantly, phenotypic variation in seasonal responsiveness among P. patens accessions collected across Europe provides the means to identify candidate regulatory genes by comparing genomic sequence and gene expression between responsive and non-responsive groups. Based on such data, our group has identified several gene families that may regulate seasonal reproduction in P. patens and are using CRISPR-Cas9 targeted gene mutagenesis in order to analyze their function. The incoming student will work alongside a Summer Science Scholar to validate and characterize CRISPR-Cas9 mutations in candidate regulators of seasonal reproduction. The student will gain experience with CRISPR-Cas9 targeted gene mutagenesis and plant transformation, along with techniques in statistics, phylogenetics, evaluation of gene expression, and plant development, all in a collaborative laboratory environment.
Course requirements: Biology 116 and 109-110 preferred but not required
Earth is home to tens of millions of species, and almost all of them depend on plants, which use light and water to spin air into sugar. In doing so, plants power Earth's ecosystems and regulate its climate, but we still have much to learn about their evolutionary history and how they interact with their environments. Research in the Kerkhoff Lab is focused on the evolution of biodiversity and ecological function of plants, using both field research and computational data science approaches.
This summer, we have two possible projects. The first is focused on the biodiversity of bryophytes, which are non-vascular plants like mosses, liverworts and hornworts. Bryophytes are descendants of some of the earliest land plants, and they exhibit patterns of biodiversity very different from the more recently evolved flowering plants. The second is focused on how forests of the Great Lakes region of the United States have changed over the two centuries since Euro-American colonization — a period of monumental climate and land use changes. Both studies utilize data compiled by thousands of plant researchers to reconstruct the evolutionary relationships and functional traits of plants at continental scales. Cascade Scholars will gain experience with quantitative measures of biodiversity, evolutionary theory, data management/analysis, digital mapping and visualization, and scientific communication. We will also spend some time in the field collecting data on local plants, which will make for a varied and fun work environment over the summer.
Course requirements: Biology 115 and 109-110
Research in Iris Levin’s lab focuses on social behavior in wild populations of barn swallows. To quantify social behavior in this colonial species, Iris puts proximity tags on the birds which log interactions between individuals. These data are used to construct social networks to answer a variety of questions related to what structures social networks (e.g., how does variation in plumage color relate to social network position?) and the consequences of variation in social interactivity (e.g., do more socially connected birds respond more strongly to stress?). Summer research in the Levin lab will involve field work near Kenyon. Students will net, band, and monitor swallows during the breeding season and contribute to a variety of research projects, including a deployment of new proximity loggers. Beyond testing the new technology, the goal of the tag deployment is to understand multi-layer networks in barn swallows. We will ask how the spatial arrangement of the birds in the barn (where they nest) is related to the social network, and how both the spatial and social networks predict mating behavior. Although barn swallows form social pair bonds during the breeding season, they mate outside of the pair bond, so we use genetic tools to identify paternity of offspring and construct sexual networks. Additionally, student projects will focus on eggshell patterns and on plumage color and parasites. A Cascade student will participate in all aspects of the research, and they will lead a study of breeding synchrony. They will use information on the timing of breeding for all birds to calculate breeding synchrony within and between 10-15 breeding colonies. Because females are only fertile for a short period of time, and because these birds mate outside of the pair bond, the degree of breeding synchrony is critical to our understanding of sexual selection in this system.
Course requirements: Biology 115
The main objective of our work is to investigate the physics of interesting materials by performing spectroscopic measurements. Due to several collaborations, we obtain novel materials that are synthesized in the hope of producing unique optical, electrical or magnetic properties. These researchers are interested in tailoring materials to ultimately produce better lasers, computers and magnetic hard drives. As a Cascade Scholar, you will be involved in performing optical measurements to decipher the intriguing physics of some of these materials.
Currently, we are working on a material called Topological Insulators (TIs), where seemingly two distinct properties of materials, namely conducting and insulating phases, are interwoven into a single material. While these materials provide a platform to address a myriad of theoretical problems in physics, because of their unique properties TIs can be exploited to produce interesting optical and electronic devices as well. The main focus of the project will be to investigate the unique properties of TIs, paying close attention to uncovering the interplay between their surface and bulk states. In addition to TIs, students will also have the opportunity to work with some inorganic nanoparticle oxide films (i.e., ZrO2 and HfO2) which are synthesized to produce interesting catalytic properties.
In order to uncover the physics of these materials, students will learn to probe the dielectric function of these materials using the in-house ellipsometers and the Fourier Transform IR spectrometer. Since these spectrometers provided a wide spectral range (between 6 meV to 6.2 eV), the dielectric function determined in this spectral range will convey information on free and bound carriers of the material. This in turn will allow us to predict the electronic transitions of these materials, and to explain the physics of some of the novel properties they manifest.
Course requirements: Physics 140/141 and 145/146
My research program examines the mechanisms of toxicity of organic pollutants in amphibians, especially developing frogs. We examine the structure, function, and evolution of the aryl hydrocarbon receptor (AHR). The AHR protein mediates the toxicity of industrial contaminants like chlorinated dioxins and biphenyls, as well as polynuclear aromatic hydrocarbons, combustion products found naturally in cigarette smoke, grilled food, and weathered crude oil. Unlike humans, Xenopus laevis frogs harbor two genes encoding AHRs. A major thrust of our work seeks to determine whether these two proteins are redundant, or if they have different functions.
A second research area considers how these pollutants disrupt the endocrine systems, including thyroid and glucocorticoid hormones. Thyroid hormone is the main driver of amphibian metamorphosis, the transition from aquatic larvae or tadpoles into terrestrial adults. We’re interested in the molecular mechanisms by which chemicals can disrupt this complex developmental process and in the morphological changes that can result. These studies use tadpoles from clawed frogs Xenopus laevis and/or X. tropicalis.
Projects in my lab employ a wide range of techniques in molecular biology and biochemistry. Summer 2020 projects will examine both cultured cell lines and animals, performing measures of gene expression (mRNA or protein) and analysis of transcription factors and their DNA binding sites.
Course requirements: Biology 116 and 109-110 required; introductory chemistry recommended
In the Reinhard lab, we use lasers to cool gases of atoms to temperatures in the microKelvin range and to excite these atoms into high-lying electronic states, with principal quantum numbers in the 40s-50s. These ultracold, highly excited atoms interact strongly with one another, even though they are neutral. The interactions lead to a phenomenon called the Rydberg excitation blockade, or a suppression of laser excitation to the high-lying states. The blockade is a key ingredient of schemes to implement quantum computers using neutral atoms. In our lab, we study processes called “state-mixing interactions” that make the blockade work less effectively. We hope that, by better understanding the processes that degrade the blockade performance, we can help enable progress in neutral atom quantum information. The cascade scholar would perform a short series of tutorials and experiments to gain proficiency with electronics, lasers, optics, atomic physics, and laser spectroscopy. Upon completion of these modules, the scholar would work with more experienced students to take and analyze data, and make upgrades and improvements to the experiment.
Course requirements: Physics 140 and 145 or Physics 240
Plants produce specialized metabolites for defense mechanisms, to attract pollinators, and to better resist other environmental stressors. In tomato (and tomato-related) plants, some of these specialized metabolites are produced by hair-like tissues on the surfaces of leaves called glandular trichomes. This summer we will be investigating a variety of primary and specialized metabolites produced by the glandular trichomes from tomato plants. The goal is to gain a better understanding of how the specialized metabolites are made and how their production affects the metabolism of primary metabolites such as fatty acids and amino acids. Scholars can expect to learn about primary and specialized metabolism in plants, use instruments such as gas chromatography-mass spectrometry, and work collaboratively with other members of the Rouhier research group.
Course requirements: None
My research group is interested in mosquito kidney function, particularly how mosquitoes remove unwanted or toxic molecules like dyes. This summer my research group is using molecular biology to determine if two particular transporters are involved in the transport of dye molecules. The project will introduce the scholar to microscopy (to harvest mosquito tissues), molecular biology (extracting RNA, amplify DNA, and sequencing of DNA) and microinjection (injecting RNA into cells for transporter assays). In addition, the scholar will practice electronic notebook keeping, discuss their research project with other scientists and non-scientists, and practice applying the scientific method within the context of fighting mosquito-borne disease.
Course requirements: None
Barn swallow eggs vary widely in the degree and distribution of speckles on the eggshell surface. Eggs (4-6) belonging to a single clutch laid by one female tend to look more similar to each other than eggs in nests laid by other females. The signature hypothesis proposes that females pattern their eggs so they can recognize them, and therefore potentially spot an egg laid in the nest by another female (intraspecific brood parasitism). This project is a continuation of student research aimed at testing the signature hypothesis. Using novel pattern recognition software, we have characterized the variation in eggshell speckle patterns in barn swallows from two geographic locations in the US. Evidence from other studies suggests that within a nest, the first and last laid eggs tend to be the most different in patterning, shape, and size. A Cascade student will investigate this in barn swallow eggs during the summer when the birds are breeding. This will entail intensive study at one breeding colony with 133 nests. Nests will be checked every day and eggs will be numbered and photographed each day as they are laid by females and returned to the nests. Additionally, the CASCADE student will also be an active participant in all aspects of Iris Levin and Toshi Tsunekage’s research on social behavior in barn swallows. Students will net, band, and monitor swallows during the breeding season and contribute to a variety of research projects, including a deployment of new proximity loggers to quantify social networks. Beyond testing the new technology, the goal of the tag deployment is to understand multi-layer networks in barn swallows. We will ask how the spatial arrangement of the birds in the barn (where they nest) is related to the social network, and how both the spatial and social networks predict mating behavior.
Course requirements: Biology 115