Publications by Colleges and Departments (MSU - Bozeman)
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Item Alternative sources of molybdenum for Methanococcus maripaludis and their implication for the evolution of molybdoenzymes(Springer Science and Business Media LLC, 2024-10) Payne, Devon; Keller, Lisa M.; Larson, James; Bothner, Brian; Colman, Daniel; Boyd, Eric S.Molybdoenzymes are essential in global nitrogen, carbon, and sulfur cycling. To date, the only known bioavailable source of molybdenum (Mo) is molybdate. However, in the sulfidic and anoxic (euxinic) habitats that predominate in modern subsurface environments and that were pervasive prior to Earth’s widespread oxygenation, Mo occurs as soluble tetrathiomolybdate ion and molybdenite mineral that is not known to be bioavailable. This presents a paradox for how organisms obtain Mo to support molybdoenzymes in these environments. Here, we show that tetrathiomolybdate and molybdenite sustain the high Mo demand of a model anaerobic methanogen, Methanococcus maripaludis, grown via Mo-dependent formate dehydrogenase, formylmethanofuran dehydrogenase, and nitrogenase. Cells grown with tetrathiomolybdate and molybdenite have similar growth kinetics, Mo content, and transcript levels of proteins involved in Mo transport and cofactor biosynthesis when compared to those grown with molybdate, implying similar mechanisms of transport and cofactor biosynthesis. These results help to reconcile the paradox of how Mo is acquired in modern and ancient anaerobes and provide new insight into how molybdoenzymes could have evolved prior to Earth’s oxygenation.Item Effect of Fines Content on Calcium Carbonate Precipitation and Thermal Properties of Biocemented Sand(American Society of Civil Engineers, 2024-04) Gunyol, Pinar; Khosravi, Mohammad; Phillips, A. J.; Plymesser, Kathryn; Parker, Albert E.In this study, the impacts to soil thermal properties during and after biocementation via microbially induced calcite precipitation (MICP) method on silty silica sand specimens with varying fines content (0%, 5%, and 15%) were investigated. Firstly, calcium conversion was measured after each pulse; then, the MICP-treated specimens were tested for cementation uniformity. The evolution of thermal conductivity of silty soils with the MICP treatment was assessed using a thermocouple probe. The results show that thermal conductivity of silty saturated sands increased by 17% for specimens treated to 9.7% CaCO3. The improvement in thermal conductivity was attributed to the formation of calcium carbonate bridges binding the soil grains together. The results suggested that the thermal conductivity of silty soil depends on water content, the number of treatment pulses, and the treatment uniformity through the soil specimen. Presence of fines content in the soil was found to play an important role in the distribution and uniformity of biocementation through the soil specimen. However, no statistically significant difference in the thermal conductivity values of MICP-treated specimens with different fines content was observed (𝑝>0.05). The average calcium carbonate content ranged between 10.7% and 7.2% for the soils with 0% and 15% fines content, respectively. The findings of this research could be used to improve the efficiency of geothermal boreholes and other energy geostructures using MICP by improving thermal conductivity of dry and partially saturated soil.Item Selenate bioreduction in a large in situ field trial(Elsevier BV, 2024-04) Hendry, M. Jim; Kirk, Lisa; Warner, Jeff; Shaw, Shannon; Peyton, Brent M.; Schmeling, Erin; Barbour, S. LeeRemoving selenium (Se) from mine effluent is a common challenge. A long-term, in situ experiment was conducted to bioremediate large volumes (up to 7500 mc d−1) of Se(VI)-contaminated water (mean 87 μg L−1) by injecting the water into a saturated waste rock fill (SRF) at a coal mining operation in Elk Valley, British Columbia, Canada. To stimulate/maintain biofilm growth in the SRF, labile organic carbon (methanol) and nutrients were added to the water prior to its injection. A conservative tracer (Br−) was also added to track the migration of injected water across the SRF, identify wells with minimal dilution and used to quantify the extent of bioreduction. The evolution of the Se species through the SRF was monitored in time and space for 201 d. Selenium concentrations of <3.8 μg L−1 were attained in monitoring wells located 38 m from the injection wells after 114 to 141 d of operation. Concentrations of Se species in water samples from complementary long-term (351–498 d) column experiments using influent Se(VI) concentrations of 1.0 mg L−1 were consistent with the results of the in situ experiment. Solid samples collected at the completion of the column experiments confirmed the presence of indigenous Se-reducing bacteria and that the sequestered Se was present as insoluble Se(0), likely in Se-S ring compounds. Based on the success of this ongoing bioremediation experiment, this technology is being applied at other mine sites.Item Through-Thickness Modulus Gradient and Pattern Fidelity of UV-Cured Thiol-Acrylate Films(American Chemical Society, 2024-08) Darabi, Amir; Cox, Lewis M.The utilization of photopolymers in diverse applications such as microfluidic devices, gas inhibitors, and biomimetic tissues has surged due to advancements in digital light processing technologies that now support multimaterial platforms, facilitating micrometer-scale control over material heterogeneity. However, significant knowledge gaps remain in our understanding of spatiotemporal evolution within these multimaterial actinic films and layers. To help bridge these gaps, a thiol-acrylate system is employed for photopatterning, and atomic force microscopy is leveraged to map through-thickness modulus profiles at various UV exposure levels, in both flood and masked curing setups. This approach enables the evolution of material properties to be tracked through the film thickness for incremental light exposure durations and across different photopatterned feature sizes. The results illustrate complicated modulus profiles that highlight the complex interplay among light exposure parameters, polymerization kinetics, oxygen inhibition, and light scattering.Item Methyl-reducing methanogenesis by a thermophilic culture of Korarchaeia(Springer Science and Business Media LLC, 2024-07) Krukenberg, Viola; Kohtz, Anthony J.; Jay, Zackary J.; Hatzenpichler, RolandMethanogenesis mediated by archaea is the main source of methane, a strong greenhouse gas, and thus is critical for understanding Earth’s climate dynamics. Recently, genes encoding diverse methanogenesis pathways have been discovered in metagenome-assembled genomes affiliated with several archaeal phyla1,2,3,4,5,6,7. However, all experimental studies on methanogens are at present restricted to cultured representatives of the Euryarchaeota. Here we show methanogenic growth by a member of the lineage Korarchaeia within the phylum Thermoproteota (TACK superphylum)5,6,7. Following enrichment cultivation of ‘Candidatus Methanodesulfokora washburnenis’ strain LCB3, we used measurements of metabolic activity and isotope tracer conversion to demonstrate methanol reduction to methane using hydrogen as an electron donor. Analysis of the archaeon’s circular genome and transcriptome revealed unique modifications in the energy conservation pathways linked to methanogenesis, including enzyme complexes involved in hydrogen and sulfur metabolism. The cultivation and characterization of this new group of archaea is critical for a deeper evaluation of the diversity, physiology and biochemistry of methanogens.Item Cultivation and visualization of a methanogen of the phylum Thermoproteota(Springer Science and Business Media LLC, 2024-07) Kohtz, Anthony J.; Petrosian, Nikolai; Krukenberg, Viola; Jay, Zackary J.; Pihofer, Martin; Hatzenpichler, RolandMethane is the second most abundant climate-active gas, and understanding its sources and sinks is an important endeavour in microbiology, biogeochemistry, and climate sciences1,2. For decades, it was thought that methanogenesis, the ability to conserve energy coupled to methane production, was taxonomically restricted to a metabolically specialized group of archaea, the Euryarchaeota1. The discovery of marker genes for anaerobic alkane cycling in metagenome-assembled genomes obtained from diverse habitats has led to the hypothesis that archaeal lineages outside the Euryarchaeota are also involved in methanogenesis3,4,5,6. Here we cultured Candidatus Methanosuratincola verstraetei strain LCB70, a member of the archaeal class Methanomethylicia (formerly Verstraetearchaeota) within the phylum Thermoproteota, from a terrestrial hot spring. Growth experiments combined with activity assays, stable isotope tracing, and genomic and transcriptomic analyses demonstrated that this thermophilic archaeon grows by means of methyl-reducing hydrogenotrophic methanogenesis. Cryo-electron tomography revealed that Ca. M. verstraetei are coccoid cells with archaella and chemoreceptor arrays, and that they can form intercellular bridges connecting two to three cells with continuous cytoplasm and S-layer. The wide environmental distribution of Ca. M. verstraetei suggests that they might play important and hitherto overlooked roles in carbon cycling within diverse anoxic habitats.Item Exploring canyons beneath Devon Ice Cap for sub-glacial drainage using radar and thermodynamic modeling(Cambridge University Press, 2024-09) Pierce, Chris; Skidmore, Mark; Beem, Lucas; Blankenship, Don; Adams, Ed; Gerekos, ChristopherSub-glacial canyon features up to 580 m deep between flat terraces were identified beneath Devon Ice Cap during a 2023 radar echo sounding (RES) survey. The largest canyon connects a hypothesized brine network near the Devon Ice Cap summit with the marine-terminating Sverdrup outlet glacier. This canyon represents a probable drainage route for the hypothesized water system. Radar bed reflectivity is consistently 30 dB lower along the canyon floor than on the terraces, contradicting the signature expected for sub-glacial water. We compare these data with backscattering simulations to demonstrate that the reflectivity pattern may be topographically induced. Our simulated results indicated a 10 m wide canal-like water feature is unlikely along the canyon floor, but smaller features may be difficult to detect via RES. We calculated basal temperature profiles using a 2D finite difference method and found the floor may be up to 18°C warmer than the terraces. However, temperatures remain below the pressure melting point, and there is limited evidence that the canyon floor supports a connected drainage system between the DIC summit and Sverdrup Glacier. The terrain beneath Devon Ice Cap demonstrates limitations for RES. Future studies should evaluate additional correction methods near complex terrain, such as RES simulation as we demonstrate here.Item The Role of Teacher Education in Improving Digital Literacy: A Pre-Service Teacher Case Study(New Prairie Press, 2024-10) Taheri, Rana; Pennington, SarahTechnology is crucial for teaching and learning in the 21st century. However, many pre-service teachers (PSTs) feel unprepared to utilize digital literacy (DL) in their future classes. This study explored PST’s perceptions of their DL knowledge and the perceived impact of their teacher education programs through a qualitative bounded case study method. Participants for this study were three PSTs engaged in a technology integration course at a land grant university in the northwestern US. Participants engaged in recorded one-on-one semi-structured interviews to learn about their perceptions and readiness for DL. The findings indicate that while PSTs were aware of DL, they lacked confidence in their ability to teach it. The study identified four critical themes related to the PSTs' perspectives on DL: concerns, challenges, advantages, and future decisions. The prioritization of DL training in teacher education programs and the reconsideration of engaging technology-related courses by universities and policymakers are recommended.Item Cost, Advocacy, and a Mechanism for Transformation: The Proposed Power of Open Access Funds(American Library Association, 2024-01) Sterman, Leila BelleAs paid open access becomes a mainstream academic practice, stakeholders must evaluate their role in the system. While open access advocates develop new ways to support the publication process and funding structure, commercial publishers continue to pivot to maintain their profit, relevance, and power in the publication system. This article provides the details of Montana State University’s Open Access Author Fund as an evaluation of the service and its impact on the local publishing ecosystem. As stewards of publicly funded knowledge, it is essential to critically analyze each new publishing route before adopting and supporting it. Especially when models claim to transform the system, librarians need to understand how an action changes the system, for whom, and at what cost.Item Short Communication: artificially reared ewes cannot be distinguished from natural reared ewes based on observed maternal behavior or lamb weaning weights(Oxford University Press, 2024-09) Posbergh, Christian J.; Miles, Asha M.; Pettifor, Natasha L.; Thonney, Michael L.Artificially rearing lambs is an important component of United States sheep production as some flocks select for increasing litter size to boost productivity. However, there is a conception among shepherds that artificially reared ewe lambs will ultimately result in poor mothers since they were not naturally raised. The objective of this study was to determine if differences in maternal behavior could be detected between ewes raised artificially and those raised naturally and if dam rearing type had an impact on lamb growth performance. Forty-eight ewes were enrolled comprised of 4 equal sized groups: artificially reared primiparous, naturally reared primiparous, artificially reared multi-parous, and naturally reared multi-parous. Ewes were observed using remote cameras to record maternal behaviors toward the lambs during and shortly after parturition. Behavior of 29 ewes during the first hour after parturition was analyzed. Independent multivariable regression models were evaluated for: proportion of time spent grooming, proportion of time spent helping the lambs nurse, number of helpful bouts, and the number of negative bouts. No statistically significant difference (P < 0.05) was detected between artificially reared and naturally reared ewes for the proportion of time spent grooming and the proportion of time spent helping the lambs nurse. Historical flock data were utilized to evaluate lamb growth between artificially and naturally reared ewes. No detrimental associations between artificially reared ewes and lamb weaning weights were observed. This study shows that artificially reared ewes are no different in terms of mothering behaviors and may be used as potential replacement candidates.