Structure-function relationship of the enzyme HIBDH

Kerry Rouhier, Chemistry

This project looks to determine the structure function relationship of an enzyme in the valine degradation pathway, HIBDH. Valine degradation is an important pathway used by organisms as an alternative to glycolysis. We are looking to better understand which amino acid residues are critical for function and maintaining structure by analyzing at least 16 different mutants of the wild-type protein. Students will learn many common biochemistry lab and computational techniques in addition to learning how to analyze primary literature and improve written and oral scientific communication skills. 

A targeted drug screen to rescue defective mitochondrial metabolism

Peter Kropp, Biology

The Kropp Lab is focused on understanding rare mitochondrial diseases by modeling those diseases in the nematode Caenorhabditis elegans (C. elegans). One of our focuses is a disease called MEPAN Syndrome, a condition caused by mutations to the protein MECR which is important in a mitochondrial fatty acid metabolism pathway. We have generated a C. elegans model of MEPAN Syndrome which, like human patients, has metabolic and neuromuscular dysfunction. This model is also unable to produce progeny, and sterility is a phenotype that is very easy to probe in drug screens. Based upon work from a collaborator, a handful of FDA-approved compounds have been successful at rescuing the loss of MECR in yeast. The goal of this Cascade project will be to test those compounds in a multicellular organism, C. elegans, to determine if they are still effective. We will test these compounds both individually and in combination to see if are capable of restoring normal fertility in our C. elegans model. If we successfully restore fertility, we will also test other phenotypes of the MEPAN model for rescue by these compounds. Cascade scholars will be part of a small, but enthusiastic research group throughout the summer.

Flight performance and sexual dimorphism in house sparrows

Natalie Wright, Biology

My lab is studying why, in some species of birds, males have larger flight muscles than females, but in other species, the pattern is reversed, and in still others, the sexes exhibit no difference in flight muscle size. One of our approaches is to test the functional effects of this sexual dimorphism in flight muscle size in birds. This summer, we will be examining whether male and female house sparrows, which differ in their flight muscle size, have different takeoff flight biomechanics. We will capture house sparrows around Gambier and use high-speed video cameras to film standardized escape-style takeoff flights in the lab. We will then digitize these videos to calculate velocity, acceleration, wingbeat frequency, and other measures of flight performance. After experimentation, we will euthanize the birds (they are an invasive species that destroys the nests of and even kills native species), dissect them to measure flight muscle and heart sizes, and test whether these or other morphological characters (e.g., wing size, shape) predict flight performance within this species. Students will learn how to safely handle wild birds, how to collect data from videos, simple physics and aerodynamics of flight, museum-quality dissection techniques, data analysis using various statistical tests in R, and data visualization in R. On rainy days, students will also help out with another ongoing project in the lab by measuring skeletons of museum bird specimens from scaled digital photographs and searching the literature for natural history data on birds. 

Annelid Regeneration

Kathy Gillen, Biology

Many animals can replace body parts lost to injury, and this ability varies depending on the species, specific organ, and developmental period. In animals studied to date, a burst of reactive oxygen species (ROS) occurs after injury and this ROS upregulation is required for proper regeneration. Among the animals, many annelids show remarkable regeneration ability, with some species, such as Lumbriculus variegatus, regrowing both head and tail ends from as few as four internal segments.  Despite their amazing regeneration abilities, we don’t know if a ROS burst is important in annelid regeneration.  We’d like to fill this knowledge gap by examining if  ROS generation is required for regeneration in our model annelid, L. variegatus. Determining the phylogenetic conservation of the ROS requirement for regeneration is interesting in its own right, and may aid regenerative medicine efforts.  To answer our question, we are chemically inhibiting the enzymes that produce reactive oxygen species, and examining the effects on regeneration. 

Another potential project this summer is developing a technique called whole-mount in situ hybridization (WMISH).  WMISH allows researchers to examine mRNA expression patterns within an intact organism.  Using this technique we can see if certain genes are upregulated in regenerating tissues, and thus perhaps required for regeneration. 

In addition to learning techniques, the Cascade scholar will maintain a lab notebook, unpack primary literature articles, discuss research ethics, troubleshoot experiments, and collaborate with other researchers.

Atmospheric Deposition in Ohio and Antarctica

Ruth Heindel, Environmental Studies

Although we often think of rain as pure water, there is a lot besides water contained in a raindrop. Through precipitation and the gravitational settling of dry particles, the atmosphere delivers essential nutrients and pollutants to ecosystems. This is true in Ohio, where the atmospheric deposition of dust and nutrients, sourced from urban, industrial, and agricultural activities, can alter ecosystems and degrade water quality. This is also true in the polar desert of the McMurdo Dry Valleys, Antarctica, where the atmospheric deposition of dust onto glaciers delivers essential nutrients for microbial life surviving in extremely harsh conditions. During the summer of 2023, research in the Heindel lab will investigate atmospheric deposition in both regions. The Cascade Science Scholar would contribute to ongoing monitoring of atmospheric deposition on the Kenyon campus, a project that involves both field and lab work. In addition, there would be opportunities to contribute to a new project investigating the mineral weathering of Antarctic dust. This project will involve regular trips to Ohio State University to make use of their state-of-the-art geochemical facilities for scanning electron microscopy, x-ray diffraction, and grain surface area analysis. The Antarctica mineral weathering project also has an exciting science communication component: our lab group, along with our collaborators at other institutions, will be developing an exhibit about our work that will be on display in Chalmers Library. A Cascade Science Scholar who joins the Heindel lab would get a taste of many components of environmental and earth science research: field work, lab work at Kenyon and at OSU, and science communication. No coursework is required for this position, but ENVS 112 would be helpful.

Gravitational-wave Physics with LIGO

Maddie Wade, Physics

Einstein’s theory of gravity, General Relativity, predicted the existence of gravitational waves, which are ripples in spacetime that travel at the speed of light. Nearly 100 years after their prediction, we were able to make the first direct detection of gravitational waves using large kilometer-scale interferometers known as the Laser Interferometer Gravitational-wave Observatory (LIGO). My lab is a member of the LIGO Scientific Collaboration. Since their initial discovery in 2015, LIGO, along with its European counterpart, Virgo, has detected nearly 100 gravitational waves coming from some of the most dramatic astrophysical events, such as colliding neutron stars and black holes.  These detections serve as a new window into understanding the universe.  

A cascade student in my lab would help on a project involving the calibration of the LIGO detectors. The LIGO detectors are calibrated using a photon calibrator, which makes use of photon radiation pressure to apply known displacements to the mirrors in the interferometer. A cascade student would spend time learning some of the basic principles of general relativity and gravitational-wave physics, learning about the calibration of the LIGO detectors and the photon calibrator system, and developing the computational skills required for the project. The project involves data analysis of the photon calibrator system’s two lasers. Students are expected to work in my lab in Hayes Hall during the work day. The necessary computers for this work will be provided to the scholar.

Androgen Action in a Rodent Reproductive Neuromuscular System

Lauren Rudolf, Neuroscience

In male rodents, mating requires the coordinated development and maintenance of neuromuscular systems. The structure and function of these reproductive circuits is highly sensitive to steroid hormones such as androgens (e.g., testosterone), which act at androgen receptors (ARs) to cause a variety of effects. Depending on the amount and timing of androgen availability, along with AR levels in the neurons and muscle, development proceeds along a male- or female-typical trajectory. In adulthood, the morphology and physiology of motor neurons and muscles involved in sexual reproduction are maintained by androgen levels. My lab is interested in how androgens act at ARs during development and adulthood to create and maintain these reproduction-critical motor neurons and muscles in male rats.

Determining the effects of maternal, prenatal stress on glycogen production in the mouse placenta

Arianna Smith, Biology

My lab studies the cellular and molecular mechanisms by which maternal stress alters the function of the placenta which, in turn, alters the health of the fetus.  Using a mouse model, we have learned that maternal stress during pregnancy reduces thyroid hormone biosynthesis in the female placental and fetal tissue (but not in tissue from males).  The current project will focus on examining the effects of maternal stress and reduced thyroid hormone on a key process in the mouse placenta - the production of glycogen! 

How kidneys sort friend from foe; using mosquitoes to assess xenobiotic transport

Matt Rouhier, Chemistry

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 microinjection to determine if two particular classes of transporters are involved in the removal of dye molecules.  The project will introduce the scholar to microscopy (preparing and injecting mosquitoes with dyes) and molecular biology (extracting RNA, amplifying DNA, and sequencing of DNA).  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.