Dr. Grant Hokit, Dr. Sam Alvey, and Dr. Jennifer Geiger
For the past three years, we have been funded by MT INBRE to study West Nile virus in Montana. Since 1999 West Nile virus (WNV) has spread across the North American continent in a heterogeneous manner creating “hot spots” of increased infection risk for humans and animals. The distribution of hot spots is poorly understood but may be driven by geographic, climatic and biological factors that determine the distribution of bridge vectors (Culex mosquitoes) and amplifying hosts (some bird species). The Carroll WNV team is developing a model of WNV infection risk for the state of Montana. Students working on this project are involved in a variety of ways. They may focus on: learning molecular protocols used to test for the presence of WNV, using DNA analytical tools to identify bird hosts from mosquito blood meals, and/or learning techniques to describe the genetic structure of vector and host populations. Additionally, students who enjoy doing field work collect mosquitoes, bird and environmental data so that we can build a predictive model of infection risk. This project allows students the opportunity to work both in the field and in the laboratory and to design their own project directed at answering some of the questions associated with this infectious disease. Recently, through collaboration with Dr. Greg Johnson at Montana State University, some students have conducted research on other infectious diseases such as heartworm, bluetongue and Cache Valley virus. The WNV faculty and students have also had the opportunity to collaborate with faculty and students from three tribal colleges: Little Big Horn College, Chief Dull Knife College, and Aaniiih Nakoda College.
We were recently awarded a four-year grant from the Howard Hughes Medical Institute (HHMI; see the award announcement at HHMI or the Carroll Press Release). The overarching objective of the HHMI funded project is to improve our ability to prepare students for biomedical research careers, to strengthen collaborations with tribal colleges, and to provide analysis of infectious diseases relevant to the Montana region.
With this HHMI funding we will: 1) formalize the ongoing collaboration associated with the WNV project into a network of cooperating faculty, tribal leaders, state and county public health officials, livestock and wildlife officials that will expand the focus beyond WNV to other infectious diseases of relevance to Montana; 2) train undergraduate students to use spatial analysis, molecular, and bioinformatic tools for the purpose of conducting a spatial epidemiological investigation. A primary goal of epidemiology is to understand the cause and consequences of the spatiotemporal heterogeneity of infectious diseases. Particularly for zoonoses, many ecological processes such as dispersal, population dynamics, and niche limitations can determine the distribution and abundance of vector and reservoir species, and consequently influence the distribution of pathogens. With the proliferation of GIS, it is now possible to create high resolution, spatially explicit risk models for studying the spatiotemporal heterogeneity of many infectious diseases; and 3) implement a digitized, web-based version of our BI/CH 477 Thesis Writing capstone course on written and oral presentation of scientific information. The web-based version of the course will be accessible to students from Carroll and elsewhere. Significant findings and relevant monitoring data will be submitted for publication in peer-reviewed journals, presented at scientific conferences, and forwarded to state health officials.
2013-2014 research students: Sean Condon, Sara Fitzpatrick, Kaya Garringer, Rylan Hull, Tyler Jacobson, Katie Newton, Carlo Pierini, and Maddie Woodruff.
Dr. Dan Gretch
Prion proteins are thought to cause neurodegenerative disease in humans and in domesticated and free-ranging animals as well. One such fatal disease is Chronic Wasting Disease in deer and elk. These diseases can be genetic in nature, arising from mutations in the prion gene. Alternatively, the diseases are transmissible. Infectious transmission is thought to stem from misfolded, infectious prion proteins (termed PrP-Sc) contacting normal prion proteins (PrP-C) and inducing them to misfold into infectious forms.
The goal of the project we are working on is to assess the role of several parameters in prion protein misfolding. We are examining the following questions: 1) Does disulfide bond formation/rearrangement influence prion misfolding?; 2) Does variation in cellular cholesterol concentration influence prion misfolding?; 3) Does alteration of prion glycosylation influence prion misfolding?; 4) Does specific allelic variation in the prion gene alter disease susceptibility by altering prion misfolding dynamics?
In vitro conversion studies can be used to monitor the conformational change event that produces infectious prions. Following incubation of the two isoforms together, PrP-C that is converted to the PrP-Sc form acquires resistance to proteolysis. Resistance to protease treatment can then be monitored via immunoblotting, and the kinetics of conversion can be assessed under the influence of different experimental variables.
Dr. Dan Gretch
We have developed an animal model to study the biochemical basis of camouflage. The tobacco hornworm is green in nature, but when fed a laboratory diet, it is blue. We speculated that the insect derives plant pigments from its diet and transports those pigments to its skin allowing it to blend into its surroundings. The yellow/orange pigment beta-carotene is a good candidate pigment since its color, when blended with blue, could produce green coloration.
Carroll student Kevin Semmens has generated both green and blue insects in the laboratory. Kevin successfully demonstrated that the plant-fed, green insects carry a pigment (spectroscopic analysis suggests that it is beta-carotene) in association with the lipoproteins in their blood stream. This provided strong evidence that beta-carotene is indeed responsible for the insects camouflage coloration. Kevin is currently testing beta-carotene in associations with other pigments to examine if the pigment absorption and transport processes involved have specificity for beta-carotene.
Funding sources: M. J. Murdock Cheritable Trust and The Guido Bugni Fund
Dr. Stefanie Otto-Hitt
The brain is composed of billions of cells, called neurons, which communicate and transmit electrical signals at specialized sites of cell-to-cell contact, called synapses. Presynaptic neurons transmit their information, in the form of neurotransmitter-filled synaptic vesicles, to postsynaptic neurons, which receive this information through a variety of receptor proteins expressed on the cell surface. For example, postsynaptic AMPA receptors bind the excitatory neurotransmitter glutamate, which results in increased excitation of the postsynaptic neuron. This mechanism of communication between a pre- and postsynaptic neuron governs the majority of excitatory synaptic transmission in the brain and is a key component of synaptic plasticity, a phenomenon referring to the remarkable ability of neurons to alter the strength of their communication.
At the synapse, AMPA receptors exist as tetrameric assemblies comprised of four distinct subunits: GluA1, GluA2, GluA3 and GluA4. Synaptic plasticity is regulated, in part, by activity-dependent variation in the number of postsynaptic GluA2-containing AMPA receptors. However, the proteins that regulate AMPA receptor trafficking at the synapse and the fundamental role this trafficking plays in synaptic plasticity remains largely unknown. Furthermore, even less is known about the mechanisms underlying transcriptional regulation of GluA2 expression and whether synaptic activity influences its rate of transcription. The goals of my lab are to (1) Identify and characterize novel GluA2-interacting proteins that regulate the trafficking of AMPA receptors at synapses and (2) Identify and characterize the transcriptional regulators of GluA2 expression.
2013-2014 research students: Caroline Cardenas, Kyle Cleasby, and Shelby Kramer
Funding sources: Private donations to the Biochemistry/Molecular Biology research fund, and the M. J. Murdock Charitable Trust
Dr. Brandon Sheafor
The amphibian research largely focuses on Panamanian golden frogs (Atelopus zeteki), a critically endangered species that is now extinct in the wild due to the fungal disease chytridiomycosis. Amphibians largely protect themselves from skin infections like chytridiomycosis by excreting compounds that are able to inhibit growth of bacteria and fungi. I have been working with zoos that have captive golden frog populations in an attempt to find a way to selectively breed frogs that will produce more effective skin secretions and, therefore, make the frogs more resistant to the fungal infection. If successful, this research could be a model for how to mitigate amphibian decline. However, unlike most other amphibians, golden frogs do not produce peptides for protective purposes, but appear to make other, novel compounds. I have collected skin secretions from hundreds of captive golden frogs and, over the last year, we have been attempting to identify the non-peptide compound(s) in the skin secretions which are responsible for the in vitro inhibition of the deadly fungus. So far, we have identified one potentially important compound, isosorbide, and are currently refining techniques in order to find more. Projects are also underway to determine if the effectiveness of skin secretions is a heritable trait and, therefore, able to be used in captive breeding programs selecting for resistance to chytridiomycosis. Finally, we do not have a strong understanding of how the fungus kills its amphibian host. Research is currently being performed to determine how the infection disrupts metabolism and respiration.
Dr. Brandon Sheafor
North American pikas are small relatives of rabbits that live at high altitudes (above tree line) throughout the Rocky Mountains. They are keystone species for the alpine ecosystems which they inhabit. Over the past decade, many populations of pikas have disappeared in their southern range, especially in the Great Basin area. These declines have been linked to climate change and the apparent inability of pikas to tolerate even moderately warm temperatures. We are currently trying to develop a western blot assay that will allow us to quantify the heat shock proteins made by pikas. This would allow us to identify whether or not climate changes are responsible for the southern declines and can help to identify populations that may be at risk in the future. It will also provide information that would be extremely valuable to climate modelers who are attempting to predict the effects of climate change on alpine ecosystems.
2013-2014 research students: Stuart Allyn and Austin Nearpass
Dr. Gerald Shields
My research attempts to describe the details of the speciation process through the study of molecular and chromosome genetics of black flies (Diptera: Simuliidae). Larvae from fresh-water streams provide the means by which we determine relationships based on sex-linked inversions in polytene chromosomes. Moreover, we have tested the validity our chromosome phylogenies (relationships) by comparing the DNAs of chromosome types. These studies tell us, contrary to the majority dogma, that chromosome change is an important and initial process of divergence in these flies. Next year we will study a population known to be the remnant of an early divergence event (Shields and Kratochvil, 2011, Amer. Mid. Naturalist). Research will involve field collection of larvae beginning early in April and chromosomal and molecular analyses of the various types.
2013-2014 research student: Jessica Brisson