Scholarworks

ScholarWorks is an open access repository for the capture of the intellectual work of Montana State University (MSU) in support of its teaching, research and service missions. MSU ScholarWorks is a central point of discovery for accessing, collecting, sharing, preserving, and distributing knowledge to the Montana State University community and the world.

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Scholarship & Research

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Metabolomic analysis of murine tissues infected with Brucella melitensis
(Public Library of Science, 2025-01) Ponzilacqua-Silva, Bárbara; Dadelahi, Alexis S.; Moley, Charles R.; Abushahba, Mostafa F. N.; Skyberg, Jerod A.
Brucella is a gram negative, facultative intracellular bacterial pathogen that constitutes a substantial threat to human and animal health. Brucella can replicate in a variety of tissues and can induce immune responses that alter host metabolite availability. Here, mice were infected with B. melitensis and murine spleens, livers, and female reproductive tracts were analyzed by GC-MS to determine tissue-specific metabolic changes at one-, two- and four- weeks post infection. The most remarkable changes were observed at two-weeks post-infection when relative to uninfected tissues, 42 of 329 detected metabolites in reproductive tracts were significantly altered by Brucella infection, while in spleens and livers, 68/205 and 139/330 metabolites were significantly changed, respectively. Several of the altered metabolites in host tissues were linked to the GABA shunt and glutaminolysis. Treatment of macrophages with GABA did not alter control of B. melitensis infection, and deletion of the putative GABA transporter BMEI0265 did not alter B. melitensis virulence. While glutaminolysis inhibition did not affect control of B. melitensis in macrophages, glutaminolysis was required for macrophage IL-1β production in response to B. melitensis. In summary, these results indicate that Brucella infection alters host tissue metabolism and that these changes could have effects on inflammation and the outcome of infection.
Lower Limit PFOA Concentrations and the Effect on Lipid Membranes
(Montana State University, 2025-05) Hemphill, Jackilyn E.; Sobolewski, Tess N.; Walker, Robert
"Poly/Perfluorinated substances (PFAS) are a class of synthetic molecules that threaten the health of communities and wildland environments. PFAS consist of carbon chains, usually 4 – 10 carbons in length, with fluorine atoms attached where hydrogen atoms would be in a hydrocarbon. Known as ‘forever chemicals’, PFAS do not break down easily in the environment and have shown an affinity for bioaccumulating in wildlife(1). They are commonly found in clothing water proofer, food packaging and firefighting foams. PFAS have also been found to cause numerous adverse health effects due to a lack of a C-F metabolic pathways in organisms. At present, the federal limit for PFOA is 4 ppt or 10-3 nM(2). It is not widely understood how PFAS at its lower limits affect biological material. This research will examine how nanomolar concentrations of perfluorooctanoic acid (PFOA) and perfluorobutanesulfonic acid (PFBS) affect model biological membranes. It is hypothesized that PFOA is partitioning the membranes of cells and will decrease membrane stability. This research will also examine whether PFOA-PFBS mixtures exhibit a Critical Micelle Concentration (CMC) or aggregation in solution. Literature has suggested that PFAS do have a CMC, however the listed concentration varies greatly."
NenŨnkUmbi/Edahiyedo-We Are Here Now: The Toolkit
(Allyson Kelley and Associates, 2025-03) Rink, Elizabeth; Firemoon, Paula; Johnson, Olivia; Secor, Molly
We Are Here Now is a holistic culturally centered intervention for American Indian youth. We Are Here Now focuses on cultural values and teachings and family, school, and community engagement to prevent substance use and sexual risk behaviors and promote positive mental health among American Indian youth. We Are Here Now includes four components: 1) a 18 module curriculum adapted from Native Stand; 2) parent education and outreach; 3) 6 cultural mentoring modules on cultural beliefs and values; and 4) systems level coordination to support young people accessing clinical health services. We Are Here Now demonstrates delayed onset of sexual intercourse, decreases in frequency of sex and alcohol and drug use drug sex, pregnancies, and increased condom use, caregiver-youth communication, and utilization of clinical services. We Are Here Now addresses: puberty and physiology, healthy relationships, prevention of pregnancy, sexually transmitted infections, and alcohol and drug use, how mental health influences choices, negotiation, refusal skills and decision making, effective communication, positive parenting, fostering positive school environments for personnel, youth, and families, cultural teachings and values, coordination and access of clinical services, community capacity building to promote positive health among youth, and effective community engagement. The toolkit for We Are Here Now provides detailed information on the content of the program’s four components for adaptation in tribal communities.
Dust on Snow Radiative Forcing and Contribution to Melt in the Colorado River Basin
(American Geophysical Union, 2025-03) Naple, Patrick; Skiles, S. Mckenzie; Lang, Otto I.; Rittger, Karl; Lenard, S. J. P.; Burgess, Annie; Painter, T. H.
In the mountainous headwaters of the Colorado River episodic dust deposition from adjacent arid and disturbed landscapes darkens snow and accelerates snowmelt, impacting basin hydrology. Patterns and impacts across the heterogenous landscape cannot be inferred from current in situ observations. To fill this gap daily remotely sensed retrievals of radiative forcing and contribution to melt were analyzed over the MODIS period of record (2001–2023) to quantify spatiotemporal impacts of snow darkening. Each season radiative forcing magnitudes were lowest in early spring and intensified as snowmelt progressed, with interannual variability in timing and magnitude of peak impact. Over the full record, radiative forcing was elevated in the first decade relative to the last decade. Snowmelt was accelerated in all years and impacts were most intense in the central to southern headwaters. The spatiotemporal patterns motivate further study to understand controls on variability and related perturbations to snow water resources.
Winter tick sharing between ungulates in the Greater Yellowstone Ecosystem and implications for apparent competition
(Wiley, 2025-01) Koser, Troy M.; Martin, Alynn; Courtemanch, Alyson B.; Thompson, Laura M.; Wise, Benjamin L.; Fralick, Gary L.; Dewey, Sarah R.; Girard, Amy; Scurlock, Brandon M.; Rogerson, Jared D.; Oyen, Kennan; Cross, Paul C.
Host species heterogeneity can drive parasite dynamics through variation in host competency as well as host abundance. We explored how elk (Cervus canadensis) with apparent subclinical infestations of winter tick (Dermacentor albipictus) may be a cryptic reservoir and drive winter tick dynamics, impacting moose (Alces alces) populations. We found that winter tick infestation loads did not vary remarkably between both host species and winter ticks sourced from elk and moose produced similar numbers of larvae which activated within 5 days of each other. We also found similar larval densities in habitats predominately used by elk, moose, and both host species. Our analysis of 2793 informative single-nucleotide polymorphisms showed genetic differentiation among tick populations that were only ~75 km apart, but fewer differences among ticks from elk or moose in the same locality, suggesting sharing of winter ticks across host species. Despite the clinical signs of high winter tick infestations being most apparent on moose, elk may be critical drivers of winter tick population dynamics and indirectly compete with moose in areas where they outnumber moose populations, a common characteristic of ungulate communities in western North America. Management interventions aimed at addressing winter tick issues on moose may wish to consider the movement patterns and abundance of cryptic reservoirs like elk.