Theses and Dissertations at Montana State University (MSU)
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Item Complexation of lipids with cyclodextrin carriers for fully defined supplementation of cell culture(Montana State University - Bozeman, College of Letters & Science, 2019) Corbin, Elizabeth Dale; Chairperson, Graduate Committee: Edward Dratz and Renee Reijo Pera (co-chair)Induced Pluripotent Stem Cells (iPSCs) hold great promise for revolutionizing medicine and research. Scientists are currently able to reprogram adult cells of almost any type to a genetically 'open' state, pluripotency, wherein they lose the characteristics of their original cell type, and revert to a state that can reproduce indefinitely, and can be differentiated to many different cell types. IPSCs are currently grown in 'chemically defined' media that contains no animal derived components. This media eliminates animal and human sera because these tend to be quite variable and confound the reprogramming process, but the chemically defined media in use has almost no lipid content. The central goal of this project was to develop methods for chemically defined addition of lipids to cell culture media. The methods developed promise to be an advance in stem cell and general cell culture methodology, providing more reproducible experimental results, and supporting cells in culture with optimized lipid contents. In order to facilitate the addition of lipids to cell culture media without animal serum or serum albumin, complexation of individual lipids with a methyl beta-cyclodextrin starch was accomplished without addition of other molecules or oxidation of delicate lipids at a 1:1 stoichiometry. The lipid/MBCD complexes are soluble in aqueous media, and can be added individually or as a mixture to cell cultures. Application of complexed lipids to stem cells and fibroblasts revealed significant differences in lipid responses. Supplementation of human fibroblasts with a mixture of complexed lipids and other elements caused a 60% increase in proliferation over a 10 day period. Supplementation of stem cells with complexed lipids significantly increased proliferation, without reduction of pluripotency. Differences in lipid responses were also found between iPSC and embryonic stem cells, that may help elucidate differences between genetic or metabolic states which may point the way for more effective reprogramming of adult cells to pluripotency.Item Effect of the WRKY76 transcription factor on starch biosynthesis and plant growth(Montana State University - Bozeman, College of Agriculture, 2016) Estabrooks, Hannah Margaret; Chairperson, Graduate Committee: Jack MartinStarch is an important contributor to plant growth as excess photosynthate is stored in leaves as starch during the day to be mobilized at night and re-synthesized in sink tissues. Starch is also the principal constituent of cereal seeds and its variation greatly influence crop yields. The starch pathway is complex and its regulation is not fully understood. Transcription Factors (TFs) are known to act as master regulators of whole biosynthetic pathways and the work presented here was aimed at gaining a better understanding of starch production in leaves by identifying a TF which specifically regulates the leaf starch biosynthetic pathway. Leaf starch levels are regulated in part by ADP-glucose pyrophosphorylase (AGPase), the rate limiting step of starch biosynthesis. Transgenic rice event (NR16+) with increased leaf AGPase activity (due to overexpression of the AGPase large and small subunit transgenes Sh2r6hs and Bt2) was subjected to RNA-sequencing. The results indicated that the leaf specific AGP transgene, which increased leaf starch, also had upregulation of the WRKY76 TF. Another regulatory protein, F-Box, was chosen as a candidate due to the F-box family's involvement in plant development. The current study examines the potential of these gene products for increasing starch biosynthesis in leaves via leaf specific overexpression. Results indicate that overexpression of WRKY76 increases leaf starch an average of 39% at both the one month and anthesis growth stages in comparison to the Varietal Control Nipponbare. WRKY76 transgenic lines have enhanced phenotype with an improved harvest index due to biomass and immature panicles trending down by 4% and 21% respectively, while seed weight trended 12% higher. Events overexpressing WRKY76 were also found to upregulate important starch biosynthetic and carbon metabolism genes including AGPL1, AGPS2, SSIIIb, GBSII, Rbcs, PRK, and GS2 as well as leading to a general upregulation of leaf tissue carbohydrates. Events 1, 2, and 12 additionally had on average 13% increased photosynthetic rate at the one month growth stage. The findings of this study support WRKY76 as a dynamic regulator of the starch biosynthetic pathway conferring more efficient carbon assimilation leading to an increased harvest index.Item A study of the consistency of starch gels prepared at a higher altitude(Montana State University - Bozeman, College of Education, Health & Human Development, 1942) Chase, Jean T.Item The decomposition of starch through phosphorolysis by Streptoccus bovis(Montana State University - Bozeman, College of Agriculture, 1957) Ushijima, Richard N.Item Barley-starch, its production, and some of its non-carbohydrate constituents(Montana State University - Bozeman, College of Letters & Science, 1956) Imsande, John DavidItem Relationship of ADP-glucose pyrophosphorylase to the regulation of starch accumulation in wheat leaves infected with Puccinia striiformis West(Montana State University - Bozeman, College of Agriculture, 1970) MacDonald, Paul WilliamItem Starch utilization, root bud correlative inhibition, and endogenous indole-3-acetic acid levels in leafy spurge (Euphorbia esula L.)(Montana State University - Bozeman, College of Agriculture, 1986) Nissen, Scott Jay; Chairperson, Graduate Committee: Michael Foley.Leafy spurge (Euphorbia esula L.) is a rapidly spreading perennial rangeland weed which continues to persist and spread despite increased efforts at biological and chemical control. The persistence of leafy spurge can be traced directly to the plant’s root carbohydrate reserves and its effective means of vegetative reproduction. Research was initiated to examine aspects of these two important survival mechanisms . Utilization of leaf, stem, root and latex starch was monitored in leafy spurge plants during a 52 day light starvation period. Leaf, stem and root starch levels decreased rapidly in light starved plants; however, detectable levels of starch were present even after 52 days without light. Latex starch levels did not change significantly. Amylase activity was present in the latex; however, latex starch granules were found to be resistant to enzymatic hydrolysis. Results indicated that latex starch granules do not function as a source of utilizable carbohydrate. Root buds were found to be quiescent during most of the growing season due to correlative inhibition rather than innate dormancy. Innate dormancy occurred when plants were in full flower; however, elongation could be stimulated by chilling intact plants for 8 days at 4 C. Exogenous applications of indole-3-acetic acid and napthalene-acetic acid at concentrations of 10 -3 M and 10 -5 M respectively, completely inhibited elongation of excised root buds. Significant increases in root bud elongation were produced by 1 mM 2,3,5-tri-iodobenzoic acid applied to stem and root tissue. These data provide evidence for the involvement of IAA in correlative control of root bud growth. Primary root and root bud endogenous IAA levels were determined at three phenologic stages: vegetative, full flower and post flower. Free IAA levels were highest in root bud of full flowering plants which were found in previous studies to have a diminished capacity to elongate. Levels of conjugated IAA increased during phenologic development. Primary root free IAA levels did not appear related to lowered root bud elongation during full flower.Item Influence of starch digestion rate on feedlot performance and site of starch digestion in beef steers fed high concentrate diets of corn or barley(Montana State University - Bozeman, College of Agriculture, 2000) Milner, Timothy JamesItem An in vitro digestion of selected starches(Montana State University - Bozeman, College of Agriculture, 1966) Davis, Ronald LyleItem Physicochemical studies on starch fractions from Phalaris canariensis(Montana State University - Bozeman, College of Letters & Science, 1968) Keng, Jiun Guang