Browsing by Subject "Sugar"

Now showing 1 - 6 of 6
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    Degradable Materials from Sugar-Derived Feedstocks
    (2019-01) Lillie, Leon
    Sugar-derived molecules have excellent potential to serve as building blocks in the development of sustainable polymers with high performance and rich functionality. This thesis focuses on the utilization of carbohydrate-derived molecules (bicyclic sugar derivatives and sugar metabolites) to enhance the degradability of polymeric materials. The first area of research presented describes the synthesis of a novel GDL-based α,ω-diene (glucarodilactone 10-undecenoate, GDLU). This molecule and its congener (isosorbide undecenoate, IU), were found to be highly suitable monomers for acyclic diene metathesis polymerization and were used to produce a family of homopolymers and copolymers of various GDLU:IU ratios. The structure/property implications of these similar sugar-derived diols on the materials physical performance and hydrolytic stability were explored. The second area of research expanded the usage of GDLU to a new class of materials, poly(ester-thioethers), with the use of photo-initiated thiol-ene polymerization. The impact of dithiol chemistry on material thermal and mechanical properties were investigated. Finally, the third area of research details the synthesis of novel methacrylic anhydride-like monomers obtained from the two-step synthetic modification of itaconic acid. These monomers were polymerized via thiol-ene polymerizations to obtain degradable, polyanhydride-based thermoset materials, with rapid neutral water degradation.
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    Identification and Characterization of Important Quantitative Trait Loci for Soluble Solids and Titratable Acidity for Germplasm in the University of Minnesota Apple Breeding Program
    (2020-12) Miller, Baylee
    Apple fruit acidity and sweetness are two of the major trait components involved in apple seedling sensory evaluation. Published studies have alluded to some of the genetic components of apple fruit acidity and sweetness, but few have included an array of germplasm relevant to the University of Minnesota apple breeding program. With the release and subsequent frequent use of ‘Honeycrisp’ and ‘Minneiska’ apple cultivars as parents at the University of Minnesota, the germplasm set deviates from other breeding programs. In order to increase breeding efficiency and increase overall quality of apple seedlings, this study describes the genetic components of apple fruit acidity and sweetness and provides breeding insights to negate the creation of undesirable apple seedlings. This study uses data from 2010 to 2018 to characterize a wide but relevant array of germplasm, using six major families, three of which have ‘Honeycrisp’ as a parent, and three of which have ‘Minneiska’ as a parent. Three major loci associated with variation in titratable acidity content on linkage groups 1, 8, and 16, and two loci associated with variation in soluble solids content on linkage groups 1 and 13 were identified, and haplotypes were characterized for each locus. The conclusions from this study provide insights for designing crosses that create seedlings with desirable ranges of acidity and sweetness characteristics.
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    Identification and characterization of three Arabidopsis sugar insensitive genes
    (2008-10) Huang, Yadong
    Carbohydrates have signaling functions in regulating gene expression, metabolic pathways and developmental processes. Eukaryotic organisms have evolved conserved and novel mechanisms for sensing and responding to sugars. Plant sugar response pathways are complex and exhibit cross-talk with other response pathways. Sugar responses and signaling pathways have been studied via physiological, biochemical and genetic approaches. Genetic screens have identified sugar response mutants with altered seedling growth phenotypes. The Gibson lab has isolated an array of sugar insensitive (sis) mutants by screening mutagenized Arabidopsis seeds on high concentrations of sugars. The identification and characterization of three of the SIS genes, SIS7, SIS3 and SIS8, are presented here. SIS7 is allelic to NCED3/STO1, an abscisic acid (ABA) biosynthetic gene, which is involved in drought and salt stress responses. Lateral root (LR) development of sis7 mutants is resistant to the inhibitory effects of osmotica. Transcriptomic analysis revealed that a set of auxin-related genes are expressed at lower levels in sis7 seeds than in wildtype seeds when incubated with glucose, suggesting that these genes may be involved in controlling LR development by both ABA and auxin. SIS3 encodes a RING finger protein that functions as an E3 ligase in in vitro ubiquitination assays. The sis3 seeds display wild-type germination responses to ABA and GA. However, the root growth of sis3 mutants has slightly reduced sensitivity to ABA. The sis8 mutants have decreased sensitivity to high sugars and hyperosmolarity. Positional cloning of sis8 revealed that the mutation is in a putative mitogen-activated protein kinase kinase kinase gene. Seed germination assays indicate that sis8 mutants have wild-type sensitivity to ABA and GA, whereas overexpression of SIS8 causes slight hypersensitive responses. Potential interaction partners of SIS8 have been identified via yeast two-hybrid screening. A T-DNA insertion in the gene encoding one potential SIS8- interacting protein, UGT72E1, causes a sis phenotype. Further studies of the SIS3 and SIS8 genes will provide more insight into the mechanisms of sugar signaling in plants.
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    Managing Feed Deliveries And Optimizing Inclusion Of Non-Antibiotic Feed Additives And Supplemental Sugar In A Cattle Feeding Program
    (2020-07) VanDerWal, Allison
    Feedlot management strategies are ever changing. Consumer perspectives, commodity market fluctuations, location, weather and demand of beef are only a few aspects that drive feedlot manager’s management decisions. Recent consumer push back towards the use of antibiotics in the cattle sold for beef has resulted in industry and academia to develop non-antibiotic alternatives to supplement calves during the receiving period. Therefore, a 49 d study was conducted to understand the effect of blended DFM, prebiotics and probiotics on receiving cattle. By day 7, cattle fed either additive had greater ADG, improved feed efficiency which continued throughout the 49 d study ultimately resulting in greater final BW compared to cattle not supplemented a nonantibiotic feed additive. In addition to improved performance parameters, health of supplemented cattle was also improved over the 49 d study in terms of decreased morbidity. Market fluctuations and increase in HCW has also directed cow/calf and feedlot producers to grow cattle prior to feeding a high concentrate diet. However, due to the location of some of these producers being primarily in areas of high forage production and pasture land, at times corn availability can be scarce and expensive requiring the need for an alternative energy source. A 70 d study was conducted in an effort to determine the optimum sugar inclusion, in the form of cane molasses, in a high forage backgrounding diet. Results from this study revealed replacing up to 10.5% of starch with sugar led to no adverse effects on intake or growth performance and energy content, and this inclusion was comparative to that of corn grain. A management strategy that continues to challenge feeders across the country is controlling variation in DMI. However, challenges in measuring variation in intake are often due to the fact that intake is determined as feed delivered on a pen basis. A considerable amount of research has been completed to understand performance responses to fluctuations feed delivered and frequency of delivery. Due to quantity of precipitation in a year in the Midwest, changes in DM of ingredients may also fluctuate DMI of cattle fed high concentrate diets. For that reason, an 84 day study was completed to understand whether as-fed dietary composition adjustments are necessary as feed ingredient DM content changes and to validate on-farm feed ingredient dry matter determination methods. Results of this study revealed adjusting as-fed dietary composition due to changes in DM content of feed ingredients daily resulted in no benefit over adjusting as-fed dietary composition every 28 d. Using a microwave and Koster tester to determine hay and corn silage DM, respectively, resulted in DM that were similar to those using laboratory procedures. However, DM estimated of high moisture corn using a Koster tester were different than DM determined using laboratory procedures.
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    Review of The Warmest December by Bernice McFadden
    (Voices from the Gaps, 2005) Malmberg, Jacob
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    The Sequencing, Assembly and Annotation of Sugar Producing Green Algae and the Design of a Low Cost Turbidostat
    (2017-10) Arriola, Matthew
    The number of sequenced genomes continues to rise at an astounding rate, however, only thirty-one green algae genomes have been sequenced to date. In this work, two green algae, Micractinium conductrix SAG 241.80 (formerly named Chlorella sp. SAG 241.80) and Chlorella sorokiniana UTEX 1602, have had their genomes sequenced and assembled de novo and functionally annotated. These two new genomes were used to investigate the genes responsible for a sugar-secreting phenotype previously described in M. conductrix SAG 241.80. When grown at a lowered pH of approximately 5.7, M. conductrix SAG 241.80 releases maltose and glucose outside of the cell, while at pH 7.6, sugar production is minimal. An additional green alga with a high sugar-releasing phenotype was isolated from the environment (Scenedesmus sp. PABB004) and found to release a quantity of sugars five-fold higher than what was found for M. conductrix SAG 241.80. Additionally, this strain did not require the low pH of 5.7 for sugar release, and produced these sugars at a physiological pH of 7.0. This work, as well as additional efforts toward developing a low-cost turbidostat for performing evolutionary experiments in microbes will be presented.