Theses and Dissertations at Montana State University (MSU)
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Item Wetland biodiversity in Grand Teton National Park(Montana State University - Bozeman, College of Letters & Science, 2022) Levandowski, Mary Lynn; Chairperson, Graduate Committee: Andrea Litt; Andrea R. Litt was a co-author of the article, 'Spatial and temporal isolation and size of wetlands influence richness and functional composition of aquatic macroinvertebrates' which is contained within this thesis.; Andrea R. Litt, Megan F. McKenna, Shan Burson and Kristin L. Legg were co-authors of the article, 'Multi-method biodiversity assessments from wetlands in Grand Teton National Park' in the journal 'Ecological indicators' which is contained within this thesis.Freshwater wetlands support high biodiversity, yet many wetlands are subject to shifts in precipitation and temperature under projected climate patterns. These changes can alter wetland hydrological regimes, potentially leading to longer or more frequent dry periods, with effects that differ among taxa. In this thesis we aim to build on the understanding about biodiversity in wetlands and how these species may be affected by climate change, in hopes of providing information for land management. To accomplish these goals, we first focused on macroinvertebrates, a group that employs diverse strategies for surviving wetland drying. We explored the roles of wetland size, spatial isolation, and temporal isolation on macroinvertebrate richness and community composition. In summer 2018, we collected macroinvertebrates from 18 wetlands in Grand Teton National Park. We found macroinvertebrate family richness increased with wetland depth and slower rates of drying. We also found the interaction between spatial and temporal isolation explained the most variation in community composition for all the life history strategies we examined. Second, we explored the utility of different automated tools to monitor biodiversity in wetlands. In 2017, we placed wildlife cameras, as well as acoustic (audible and ultrasonic) recorders at 4 permanent wetlands in Grand Teton National Park for a week in June and August; we also completed a visual survey during each of these time intervals. We compared the number and type of species detected by each method over the summer to evaluate the effectiveness of each method for monitoring. Using wildlife cameras, in addition to visual surveys, increased the observation time at surveyed wetlands, captured complementary species, and recorded dynamics in the water level during the summer. These two chapters provide insights about how changes resulting from increased drying may affect one of the most biodiverse taxa and offer methods that allow monitoring of many taxa simultaneously.Item Improving the two-photon absorption properties of fluorescent proteins for neuroscience(Montana State University - Bozeman, College of Letters & Science, 2020) Molina, Rosana Sophia; Chairperson, Graduate Committee: Thomas Hughes; Yong Qian, Jiahui Wu, Yi Shen, Robert E. Campbell, Mikhail Drobizhev and Thomas E. Hughes were co-authors of the article, 'Understanding the fluorescence change in red genetically encoded calcium ion indicators' in the journal 'Biophysical Journal' which is contained within this dissertation.; Tam M. Tran, Robert E. Campbell, Gerard G. Lambert, Anya Salih, Nathan C. Shaner, Thomas E. Hughes and Mikhail Drobizhev were co-authors of the article, 'Blue-shifted green fluorescent protein homologues are brighter than enhanced green fluorescent protein under two-photon excitation' in the journal 'The Journal of physical chemistry letters' which is contained within this dissertation.; Jonathan King, Jacob Franklin, Nathan Clack, Christopher McRaven, Vasily Goncharov, Daniel Flickinger, Karel Svoboda, Mikhail Drobizhev, Thomas E. Hughes were co-authors of the article, 'An instrument to optimize fluorescent proteins for two-photon excitation' which is contained within this dissertation.Untangling the intricacies of the brain requires innovative tools that power basic research. Fluorescent proteins, first discovered in jellyfish, provide a genetically encodable way to light up the brains of animal models such as mice and fruit flies. They have been made into biosensors that change fluorescence in response to markers of neural activity such as calcium ions (Ca 2+). To visualize them, neuroscientists take advantage of two-photon excitation microscopy, a specialized type of imaging that can reveal crisp fluorescence images deep in the brain. Fluorescent proteins behave differently under twophoton excitation compared to one-photon excitation. Their inherent two-photon properties, namely brightness and peak absorption wavelength, limit the scope of possible experiments to investigate the brain. This work aims to understand and improve these properties through three projects: characterizing a set of red fluorescent protein-based Ca 2+ indicators; finding two-photon brighter green fluorescent proteins; and developing an instrument to screen for improved fluorescent proteins for two-photon microscopy. Analyzing nine red Ca 2+ indicators shows that they can be separated into three classes based on how their properties change in a Ca 2+-dependent manner. In one of these classes, the relative changes in one-photon properties are different from the changes in two-photon properties. In addition to characterizing, identifying and directly improving fluorescent proteins for enhanced two-photon properties is important. Presented here is a physical model of the light-absorbing molecule within the green fluorescent protein (the chromophore). The model predicts that green fluorescent proteins absorbing at higher energy wavelengths will be brighter under two-photon excitation. This proves to be the case for 12 blueshifted green fluorescent proteins, which are up to 2.5 times brighter than the commonly used Enhanced Green Fluorescent Protein. A way to directly improve fluorescent proteins is through directed evolution, but screening under two-photon excitation is a challenge. An instrument, called the GIZMO, solves this challenge and can evolve fluorescent proteins expressed in E. coli colonies under two-photon excitation. These results pave the way for better two-photon fluorescent protein-based tools for neuroscience.Item A new instrument for determining strength and temperature profiles in snowpack(Montana State University - Bozeman, College of Engineering, 1984) Dowd, Timothy FrancisThe purpose of this thesis project was the development of a new field instrument for determining strength and temperature profiles in snowpack. The standard tool now used for strength determination is the ram penetrometer, which is slow, cumbersome, inaccurate, and does not provide immediate results. Temperatures are generally taken with a dial stem thermometer in a snowpit wall, which is difficult to do accurately at specific intervals. The Digital Thermo-Resistograph was designed and built in an attempt to improve field snowpack data collection. The Digital Thermo-Resistograph is a portable microprocessor-based data acquisition system for quick and accurate field collection of snowpack compressive strength and temperature data. This was accomplished by building a probe with a load cell and thermistor, a small snow platform for probe position information, and a Z-80 microprocessor-based data acquisition system. The system provides information in digital form for every sampled point. A 64 x 240 dot matrix LCD graphic display unit is used to show complete strength and temperature profiles in the field. Provision is made to transfer these profiles to paper via an ordinary X-Y recorder for a permanent record of field data. Sufficient memory for the storage of 25 profiles is provided. The results of winter 1984 field tests are presented. The thermistor could not be made- to work accurately, and so was not integrated into the system. The Digital Thermo-Resistograph proved to be fast and reliable in collecting compressive snow strength information, which is measured from 0.0 to 2.55 kg/sq cm at five mm increments through the snowpack. Comparisons with the ram penetrometer are shown. Ideas for future developments are discussed.