College of Letters & Science

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The College of Letters and Science, the largest center for learning, teaching and research at Montana State University, offers students an excellent liberal arts and sciences education in nearly 50 majors, 25 minors and over 25 graduate degrees within the four areas of the humanities, natural sciences, mathematics and social sciences.

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Attraction, Entrance, and Passage Efficiency of Arctic Grayling, Trout, and Suckers at Denil Fishways in the Big Hole River Basin, Montana
(Wiley, 2022-07) Triano, Ben; Kappenman, Kevin M.; McMahon, Thomas E.; Blank, Matt; Heim, Kurt C.; Parker, Albert E.; Zale, Alexander V.; Platt, Nolan; Plymesser, Katey
The Big Hole River basin in southwestern Montana supports the only indigenous, self-sustaining fluvial population of Arctic Grayling Thymallus arcticus in the conterminous United States, but the basin is fragmented by numerous low-head irrigation diversion dams. Denil fishways at 63 diversion dams provide Arctic Grayling and other fishes opportunities for year-round access to critical habitats; however, their efficiency has not been evaluated. We quantified attraction, entrance, and passage for hatchery-reared Arctic Grayling, wild trout (Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta), and wild suckers (White Sucker Catostomus commersonii and Longnose Sucker C. catostomus) during 14 field trials conducted at six Denil fishways over a representative range of fishway slopes and hydraulic conditions using passive integrated transponder telemetry. Attraction (60.4–84.3%) and entrance (44.3–78.6%) efficiencies were variable across test conditions and reduced overall fishway efficiencies (19.1–55.8%). In contrast, upon entry, passage efficiencies were high (96.2–97.0%) for all taxa across all test conditions. Attraction of hatchery-reared Arctic Grayling increased with upstream depth (a surrogate for fishway discharge) and attraction flow, but attraction of wild fish was less affected by these conditions. Entrance of Arctic Grayling, Brook Trout, and Brown Trout decreased with upstream depth and fishway slope, especially when plunging entrance conditions associated with shallow downstream depths were present. However, entrance of Arctic Grayling and both trout species increased with downstream depth, and submerged fishway entrances demonstrated promise for increasing entrance efficiency at fishways with high discharges and steep slopes. We demonstrate that comprehensive evaluations of fishway efficiency components can identify specific solutions that improve fishway efficiency; application of these engineering solutions at individual fishways (as needed) could improve their efficiency and further enhance aquatic connectivity for fishes in the Big Hole River basin and elsewhere.
Imaging and plate counting to quantify the effect of an antimicrobial: A case study of a photo‐activated chlorine dioxide treatment
(Wiley, 2022-09) Parker, Albert E.; Miller, Lindsey; Adams, Jacob; Pettigrew, Charles; Buckingham‐Meyer, Kelli; Summers, Jennifer; Christen, Andres; Goeres, Darla
Aim. To assess removal versus kill efficacies of antimicrobial treatments against thick biofilms with statistical confidence. Methods and results. A photo-activated chlorine dioxide treatment (Photo ClO2) was tested in two independent experiments against thick (>100 μm) Pseudomonas aeruginosa biofilms. Kill efficacy was assessed by viable plate counts. Removal efficacy was assessed by 3D confocal scanning laser microscope imaging (CSLM). Biovolumes were calculated using an image analysis approach that models the penetration limitation of the laser into thick biofilms using Beer's Law. Error bars are provided that account for the spatial correlation of the biofilm's surface. The responsiveness of the biovolumes and plate counts to the increasing contact time of Photo ClO2 were quite different, with a massive 7 log reduction in viable cells (95% confidence interval [CI]: 6.2, 7.9) but a more moderate 73% reduction in biovolume (95% CI: [60%, 100%]). Results are leveraged to quantitatively assess candidate CSLM experimental designs of thick biofilms. Conclusions. Photo ClO2 kills biofilm bacteria but only partially removes the biofilm from the surface. To maximize statistical confidence in assessing removal, imaging experiments should use fewer pixels in each z-slice, and more importantly, at least two independent experiments even if there is only a single field of view in each experiment. Significance and impact of study There is limited penetration depth when collecting 3D confocal images of thick biofilms. Removal can be assessed by optimally fitting Beer's Law to all of the intensities in a 3D image and by accounting for the spatial correlation of the biofilm's surface. For thick biofilms, other image analysis approaches are biased or do not provide error bars. We generate unbiased estimates of removal and assess candidate CSLM experimental designs of thick biofilms with different pixilations, numbers of fields of view and number of experiments using the included design tool.
Activity-based cell sorting reveals responses of uncultured archaea and bacteria to substrate amendment
(2020) Reichart, Nicholas J.; Jay, Zackary J.; Krukenberg, Viola; Parker, Albert E.; Lange Spietz, Rachel K.; Hatzenpichler, Roland
Metagenomic studies have revolutionized our understanding of the metabolic potential of uncultured microorganisms in various ecosystems. However, many of these genomic predictions have yet to be experimentally tested, and the functional expression of genomic potential often remains unaddressed. In order to obtain a more thorough understanding of cell physiology, novel techniques capable of testing microbial metabolism under close to in situ conditions must be developed. Here, we provide a benchmark study to demonstrate that bioorthogonal non-canonical amino acid tagging (BONCAT) in combination with fluorescence-activated cell sorting (FACS) and 16S rRNA gene sequencing can be used to identify anabolically active members of a microbial community incubated in the presence of various growth substrates or under changing physicochemical conditions. We applied this approach to a hot spring sediment microbiome from Yellowstone National Park (Wyoming, USA) and identified several microbes that changed their activity levels in response to substrate addition, including uncultured members of the phyla Thaumarchaeota, Acidobacteria, and Fervidibacteria. Because shifts in activity in response to substrate amendment or headspace changes are indicative of microbial preferences for particular growth conditions, results from this and future BONCAT-FACS studies could inform the development of cultivation media to specifically enrich uncultured microbes. Most importantly, BONCAT-FACS is capable of providing information on the physiology of uncultured organisms at as close to in situ conditions as experimentally possible.
Interlaboratory study for the evaluation of three microtiter plate-based biofilm quantification methods
(2021-07) Allkja, Jontana; van Charante, Frits; Aizawa, Juliana; Reigada, Ines; Guarch-Perez, Clara; Vazquez-Rodriguez, Jesus Augusto; Cos, Paul; Coenye, Tom; Fallarero, Adyary; Zaat, Sebastian A. J.; Felici, Antonio; Ferrari, Livia; Azevado, Nuno F.; Parker, Albert E.; Goeres, Darla M.
Microtiter plate methods are commonly used for biofilm assessment. However, results obtained with these methods have often been difficult to reproduce. Hence, it is important to obtain a better understanding of the repeatability and reproducibility of these methods. An interlaboratory study was performed in five different laboratories to evaluate the reproducibility and responsiveness of three methods to quantify Staphylococcus aureus biofilm formation in 96-well microtiter plates: crystal violet, resazurin, and plate counts. An inter-lab protocol was developed for the study. The protocol was separated into three steps: biofilm growth, biofilm challenge, biofilm assessment. For control experiments participants performed the growth and assessment steps only. For treatment experiments, all three steps were performed and the efficacy of sodium hypochlorite (NaOCl) in killing S. aureus biofilms was evaluated. In control experiments, on the log10-scale, the reproducibility SD (SR) was 0.44 for crystal violet, 0.53 for resazurin, and 0.92 for the plate counts. In the treatment experiments, plate counts had the best responsiveness to different levels of efficacy and also the best reproducibility with respect to responsiveness (Slope/SR = 1.02), making it the more reliable method to use in an antimicrobial efficacy test. This study showed that the microtiter plate is a versatile and easy-to-use biofilm reactor, which exhibits good repeatability and reproducibility for different types of assessment methods, as long as a suitable experimental design and statistical analysis is applied.
Investigation of the role of infusate properties related to midline catheter failure in an ovine model
(2020-08) Ryder, Marcia; Gunther, Robert A.; Nishikawa, Reid A.; Stranz, Marc; Meyer, Britt M.; Spangler, Taylor A.; Parker, Albert E.; Sylvia, Charles
Purpose Infusate osmolarity, pH, and cytotoxicity were investigated as risk factors for midline catheter failure. Methods An experimental, randomized, controlled, blinded trial was conducted using an ovine model. Two 10-cm, 18-gauge single-lumen midline catheters were inserted into the cephalic veins of sheep. The animals were divided into 6 study arms and were administered solutions of vancomycin 4 mg/mL (a low-cytotoxicity infusate) or 10 mg/mL (a high-cytotoxicity infusate), doxycycline 1 mg/mL (an acidic infusate), or acyclovir 3.5 mg/mL (an alkaline infusate) and 0.9% sodium chloride injection; or 1 of 2 premixed Clinimix (amino acids in dextrose; Baxter International) products with respective osmolarities of 675 mOsm/L (a low-osmolarity infusate) and 930 mOsm/L (a mid-osmolarity infusate). Contralateral legs were infused with 0.9% sodium chloride injection for control purposes. Catheter failure was evaluated by assessment of adverse clinical symptoms (swelling, pain, leakage, and occlusion). A quantitative vessel injury score (VIS) was calculated by grading 4 histopathological features: inflammation, mural thrombus, necrosis, and perivascular reaction. Results Among 20 sheep included in the study, the overall catheter failure rate was 95% for test catheters (median time to failure, 7.5 days; range, 3–14 days), while 60% of the control catheters failed before or concurrently (median time to failure, 7 days; range, 4.5–14 days). Four of the 6 study arms (all but the Clinimix 675-mOsm/L and acyclovir 3.5-mg/mL arms) demonstrated an increase in mean VIS of ≥77% in test vs control legs (P ≤ 0.034). Both pain and swelling occurred at higher rates in test vs control legs: 65% vs 10% and 70% vs 50%, respectively. The mean difference in rates of occlusive pericatheter mural thrombus between the test and control arms was statistically significant for the vancomycin 10-mg/mL (P = 0.0476), Clinimix 930-mOsm/L (P = 0.0406), and doxycycline 1-mg/mL (P = 0.032) arms. Conclusion Administration of infusates of varied pH, osmolarity, and cytotoxicity via midline catheter resulted in severe vascular injury and premature catheter failure; therefore, the tested infusates should not be infused via midline catheters.
Impact of an automated hand hygiene monitoring system and additional promotional activities on hand hygiene performance rates and healthcare-associated infections
(2019-07) Boyce, John M.; Laughman, Jennifer A.; Ader, Michael H.; Wagner, Pamela T.; Parker, Albert E.; Arbogast, James W.
Objective: Determine the impact of an automated hand hygiene monitoring system (AHHMS) plus complementary strategies on hand hygiene performance rates and healthcare-associated infections (HAIs). Design: Retrospective, nonrandomized, observational, quasi-experimental study. Setting: Single, 93-bed nonprofit hospital. Methods: Hand hygiene compliance rates were estimated using direct observations. An AHHMS, installed on 4 nursing units in a sequential manner, determined hand hygiene performance rates, expressed as the number of hand hygiene events performed upon entering and exiting patient rooms divided by the number of room entries and exits. Additional strategies implemented to improve hand hygiene included goal setting, hospital leadership support, feeding AHHMS data back to healthcare personnel, and use of Toyota Kata performance improvement methods. HAIs were defined using National Healthcare Safety Network criteria. Results: Hand hygiene compliance rates generated by direct observation were substantially higher than performance rates generated by the AHHMS. Installation of the AHHMS without supplementary activities did not yield sustained improvement in hand hygiene performance rates. Implementing several supplementary strategies resulted in a statistically significant 85% increase in hand hygiene performance rates (P < .0001). The incidence density of non–Clostridioies difficile HAIs decreased by 56% (P = .0841), while C. difficile infections increased by 60% (P = .0533) driven by 2 of the 4 study units. Conclusion: Implementation of an AHHMS, when combined with several supplementary strategies as part of a multimodal program, resulted in significantly improved hand hygiene performance rates. Reductions in non–C. difficile HAIs occurred but were not statistically significant.
Randomized controlled trial evaluating the antimicrobial efficacy of chlorhexidine gluconate and para-chloro-meta-xylenol handwash formulations in real-world doses
(2019-06) Arbogast, James W.; Bowersock, Lisa B.; Parker, Albert E.; Macinga, D. R.
Chlorhexidine gluconate-based soaps have become the gold standard for handwashing in critical care settings and para-chloro-meta-xylenol is an effective alternative antibacterial active ingredient. This study benchmarked 2 novel foaming handwashes, compared to a bland soap for antimicrobial effectiveness using the health care personnel handwash method at realistic soap doses (0.9 mL and 2.0 mL). To our knowledge, this is the first published efficacy study on realistic soap doses. Both soaps met Food and Drug Administration success criteria.
Quorum sensing inhibition as a promising method to control biofilm growth in metalworking fluids
(2019-04) Ozcan, Safiye S.; Dieser, Markus; Parker, Albert E.; Balasubramanian, Narayanaganesh; Foreman, Christine M.
Microbial contamination in metalworking systems is a critical problem. This study determined the microbial communities in metalworking fluids (MWFs) from two machining shops and investigated the effect of quorum sensing inhibition (QSI) on biofilm growth. In both operations, biofilm-associated and planktonic microbial communities were dominated by Pseudomonadales (60.2–99.7%). Rapid recolonization was observed even after dumping spent MWFs and meticulous cleaning. Using Pseudomonas aeruginosa PAO1 as a model biofilm organism, patulin (40 µM) and furanone C-30 (75 µM) were identified as effective QSI agents. Both agents had a substantially higher efficacy compared to α-amylase (extracellular polymeric substance degrading enzyme) and reduced biofilm formation by 63% and 76%, respectively, in MWF when compared to untreated controls. Reduced production of putatively identified homoserine lactones and quinoline in MWF treated with QS inhibitors support the effect of QSI on biofilm formation. The results highlight the effectiveness of QSI as a potential strategy to eradicate biofilms in MWFs.
Dynamic processing of DOM: Insight from exometabolomics, fluorescence spectroscopy, and mass spectrometry
(2018-06) Smith, Heidi J.; Tigges, Michelle M.; D'Andrilli, Juliana; Parker, Albert E.; Bothner, Brian; Foreman, Christine M.
Dissolved organic matter (DOM) in freshwater environments is an important source of organic carbon, supporting bacterial respiration. Frozen environments cover vast expanses of our planet, with glaciers and ice-sheets storing upwards of 6 petagrams of organic carbon. It is generally believed that DOM liberated from ice stimulates downstream environments. If true, glacial DOM is an important component of global carbon cycling. However, coupling the release of DOM to microbial activity is challenging due to the molecular complexity of DOM and the metabolic connectivity within microbial communities. Using a single environmentally relevant organism, we demonstrate that processing of compositionally diverse DOM occurs, but, even though glacially derived DOM is chemically labile, it is unable to support sustained respiration. In view of projected changes in glacier DOM export, these findings imply that biogeochemical impacts on downstream environments will depend on the reactivity and heterogeneity of liberated DOM, as well as the timescale.
Community Engaged Cumulative Risk Assessment of Exposure to Inorganic Well Water Contaminants, Crow Reservation, Montana
(2018-01) Eggers, Margaret J.; Doyle, John T.; Lefthand, M. J.; Young, Sara L.; Moore-Nall, Anita L.; Kindness, L.; Medicine, R. O.; Ford, Tim E.; Dietrich, E.; Parker, Albert E.; Hoover, J. H.; Camper, Anne K.
An estimated 11 million people in the US have home wells with unsafe levels of hazardous metals and nitrate. The national scope of the health risk from consuming this water has not been assessed as home wells are largely unregulated and data on well water treatment and consumption are lacking. Here, we assessed health risks from consumption of contaminated well water on the Crow Reservation by conducting a community-engaged, cumulative risk assessment. Well water testing, surveys and interviews were used to collect data on contaminant concentrations, water treatment methods, well water consumption, and well and septic system protection and maintenance practices. Additive Hazard Index calculations show that the water in more than 39% of wells is unsafe due to uranium, manganese, nitrate, zinc and/or arsenic. Most families’ financial resources are limited, and 95% of participants do not employ water treatment technologies. Despite widespread high total dissolved solids, poor taste and odor, 80% of families consume their well water. Lack of environmental health literacy about well water safety, pre-existing health conditions and limited environmental enforcement also contribute to vulnerability. Ensuring access to safe drinking water and providing accompanying education are urgent public health priorities for Crow and other rural US families with low environmental health literacy and limited financial resources.

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