Doctor of Philosophy, The Ohio State University, 2022, Food Science and Technology

As natural colorants get more attention in the food industry, efforts on anthocyanin (ACN) stabilization and color expression have increased for their incorporation in food products. Studies show enhancement of ACN color performance and resistance to degradation by stabilizing the pigment via intramolecular copigmentation. This reaction occurs between the ACN chromophore and its covalently bound acyl group on the glycoside. In plants, most acylating groups exist in the trans-isomeric configuration but can undergo excitation under ultraviolet and visible light to induce the cis-conformation. The applied radiant energy affects the isomerization barrier, causing the molecule to adopt its excited state, and producing a molecule with different chemical characteristics. Photochromism, defined as “light-induced, reversible change in color,” is the reaction that occurs when photoisomerization of molecules lead to a change in color. Relatedly, cis- and trans- acylated ACN have been known to exhibit differences in color expression and stability, but details on the factors affecting photochromism has not been well studied. The overall objective of this study was to investigate the conditions that influence photochromism of acylated ACN and compare the cis-trans isomers' spectroscopic characteristics, colorimetry, and stability in various pHs. In the first objective, the effects of irradiation time and excitation energy on ACN cis-trans isomerization and color expression were studied. East Asian eggplants were chosen as the source of the pigment, due to their simple ACN profile that contained the trans-isomer necessary to induce isomerization. Delphidin-3-(trans-p-coumaroyl)-rutinoside-5- glucoside, delphinidin-3-(cis-p-coumaroyl)-rutinoside-5-glucosde, and a semi-crude extract containing both isomers were characterized, standardized, and subjected to excitation (UV chamber at 254 nm, 365 nm, visible light with D65 lamp, and F2 lamp) for up to 20 hours. All four radiant ener (open full item for complete abstract)

Committee: M. Monica Giusti (Advisor); Rafael Jimenez-Flores (Committee Member); Luis Rodriguez-Saona (Committee Member); Emmanuel Hatzakis (Committee Member) Subjects: Agricultural Chemicals; Analytical Chemistry; Food Science

Bachelor of Science, Wittenberg University, 2021, Biology

Glyphosate has been shown to impact not only amphibian survival, but also their development, phenotypic response to predators, and overall behavior. Dicamba, another herbicide, was permitted for use by the EPA in 2016. However, less is known about its potential environmental impact. Being an extremely volatile chemical, dicamba poses a risk to aquatic organisms in areas that may experience runoff or overspray. It can also harm yields of neighboring crops, leading the EPA to ban dicamba use part way through this experiment in June 2020. We investigated the effects of an environmentally relevant dosage of two forms of dicamba on grey treefrog tadpole development and behavior. We also investigated how dicamba impacted the response of tadpoles to predator cues. Herbicide treatment significantly decreased growth compared to the control. The presence of predator cues also significantly decreased growth, and there was no interaction between herbicide treatment and predator treatment. Tadpoles exposed to predator cues generally had wider tails, and the introduction of dicamba caused similar morphological changes. The presence of commercial dicamba also significantly reduced startle responses, potentially increasing the risk for predation. Dicamba has the potential for sublethal impacts on the development and behavior of tadpoles, and therefore should be further studied.

Committee: Amber Burgett (Advisor); Richard Phillips (Committee Member); Doug Andrews (Committee Member) Subjects: Agricultural Chemicals; Animal Sciences; Animals; Aquatic Sciences; Biology; Environmental Science; Statistics; Zoology

Master of Science, University of Toledo, 2021, Geology

Recent research investigating the contributions of non-point legacy dissolved reactive phosphorus (DRP) sources to DRP loading in the Maumee River watershed has relied heavily on edge of field methods. While edge of field methods consider the hydraulic and chemical parameters of tile drainage and overland flow, these studies neglect to consider the field-scale groundwater flow regimes which control the mobilization and advection of DRP to tile drains. Understanding the field-scale advective capacity of groundwater can aid in the assessment and modeling of the impacts of legacy sources on watershed DRP loading. A tile drained farm field with legacy soil P accumulation resulting from decades of biosolid applications within the Maumee River watershed was selected as a study site to evaluate the advective capacity of two groundwater flow regimes: rapid return flow (RRF) and slower groundwater baseflow (SBF). 15 piezometers were installed throughout the farm field to characterize the unconfined aquifer, monitor the potentiometric surface, and permit groundwater sampling. Hydrograph separation of piezometer and tile drain hydrographs yielded the RRF and SBF components of groundwater and tile discharge. The legacy P source in the soil profile was characterized by sampling the soil profile at increasing depths. Results show significant legacy soil P accumulation in the near surface soil profile (100-300ppm soil test phosphorus, 0-60cm), with a stratification of concentrations that decreased as depth in the soil profile increased. Elevated groundwater DRP concentrations observed after recharge indicate that gravity drainage is mobilizing legacy P sequestered in the soil profile. The RRF component of piezometer hydrographs was found to transport considerably less DRP than SBF, accounting for 13% of total discharge and 11% of DRP mass transported. This regime dynamic was also present in groundwater and tile drain discharge as baseflow. The total DRP mass discharged by (open full item for complete abstract)

Committee: James Martin-Hayden Dr. (Advisor); Daryl Dwyer Dr. (Committee Member); Kevin Czajkowski Dr. (Committee Member) Subjects: Agricultural Chemicals; Environmental Geology; Environmental Science; Geology; Hydrologic Sciences; Hydrology; Water Resource Management

Bachelor of Science, Wittenberg University, 2021, Biology

Insecticide use is steadily increasing in the United States. Of these, the insecticide Sevin™ has the active ingredient carbaryl, which is a xenobiotic. This is a reverse inhibitor of acetylcholinesterase, which prevents nerve excitation causing paralysis and death in insects. Though insects are the target species, carbaryl has many routes of exposure such as run-off, inhalation, and physical contact making it easy to encounter for non-target species like aquatic life and humans. Carbaryl has been studied within in vitro models to test its effects on zebrafish. The insecticide has already been shown to act on the acetylcholinesterase (AChE) pathway, but it also has potential to act on a second pathway: the aryl hydrocarbon receptor (AhR) pathway. Zebrafish genes and genetic pathways are homologous to humans, allowing for insight on how carbaryl could be affecting humans as well. This study set out to use an in vivo model to show how carbaryl is inducing cytochrome P450 or other AhR pathway gene expression. Gene expression of carbaryl treated embryos were compared to untreated embryos to examine this possible relationship. Cyp1a and cyp1b gene expression was increased with an increase in carbaryl concentration suggesting that carbaryl may be causing induction of the AhR pathway.

Committee: Michelle McWhorter (Advisor); Matthew Collier (Committee Member); Daniel Marous (Committee Member) Subjects: Agricultural Chemicals; Biochemistry; Biology; Developmental Biology; Environmental Science; Genetics; Molecular Biology; Toxicology

Master of Science (MS), Bowling Green State University, 2020, Biological Sciences

As headwaters transporting agricultural runoff to streams and lakes, agricultural ditches may be a key component to reducing nutrient loading and harmful algal blooms. While conventional trapezoidal ditches are the most widely used, two stage ditches and self-forming streams are starting to be constructed as a means of management. Two stage ditches and self-forming streams may be useful for their wider floodplains, allowing slower movement of water and less erosion, promoting environments that retain and remove more nutrients than the more narrow conventional ditches. Here I examined multiple nutrient pools and fluxes (plants, invertebrates, sediments, water, and biofilm) of phosphorus and nitrogen in both May and July of 2018. I also tested the effects of isopods on nutrient cycling in ditch sediments in laboratory experiments. The results showed that ditch morphology did little to impact the concentration of nutrients, but did alter nutrient density and total nutrient retention, which was related to the width of the ditch. Plant and sediment pools were found to retain the most nutrients. Self-forming streams retained the most nutrients but supported a low biomass and diversity of invertebrates which can be important in nutrient cycling and multiple ecosystem functions. Bioturbation was found to be less important than excretion with invertebrates that rework surface sediments. Overall, my results suggest two stage ditches may balance increased nutrient retention while at the same time maintain aquatic habitat quality.

Committee: Kevin McCluney Dr. (Advisor); Enrique Gomezdelcampo Dr. (Committee Member); James Hood Dr. (Committee Member); Helen Michaels Dr. (Committee Member) Subjects: Agricultural Chemicals; Agriculture; Biology; Ecology; Geomorphology; Hydrology; Water Resource Management

Master of Science, Miami University, 2020, Chemistry and Biochemistry

Condensed tannins (CT) are high molecular weight compounds, comprised of flavan-3-ol monomers stabilized by C-C interflavan bonds. They are found in plants and affect food astringency, protein availability, and biogeochemical cycles. Tannins are highly sorptive, making them difficult to analyze using existing methods. Recently, we developed methods using Fourier Transform Ion Cyclotron Resonance Matrix Assisted Laser Desorption/Ionization mass spectrometry (FT-ICR MALDI-MS) to obtain exact masses of polymer species. Using CT from Sorghum grain, we obtained spectra that exhibited peaks consistent with the (epi)catechin composition, previously proposed. However, the spectra also exhibited peaks that suggested the tannin contained ester groups. Using thiolysis, methanolysis, NMR, and Fourier Transform Infrared Spectroscopy (FTIR), we confirmed that the tannin does not contain ester groups. Instead, we propose that the MALDI matrix 2,5-dihydroxy benzoic acid forms adducts with the procyanidin that survive ionization and yield misleading MS peaks. To further characterize CT, we are developing reversed phase High Performance Liquid Chromatography (RP-HPLC) methods that separate polymers based on molecular weight. This is an improvement over previous methods that give a "hump" for most tannin extracts. Combining MALDI analysis with better HPLC methods will improve the potential to establish the roles of CT in diverse environments.

Committee: Ann Hagerman (Advisor); Neil Danielson (Committee Member); Andrea Kravats (Committee Member); Heeyoung Tai (Committee Member) Subjects: Agricultural Chemicals; Analytical Chemistry; Biochemistry; Chemistry; Food Science; Polymers

Doctor of Philosophy (PhD), Ohio University, 2020, Chemical Engineering (Engineering and Technology)

Pesticides volatilize from soil and plant surfaces to the atmosphere after spray applications in agricultural fields which can cause inhalational exposure to bystanders. It is important to quantify such volatilization with reasonable confidence for risk assessment of the inhalation exposure. A mechanistic model was developed here to simulate the underlying transport processes and deploy it as a standalone tool that a regulatory body can use to predict volatilization emissions of various pesticides for determination of inhalation exposure. The overall volatilization model includes a soil sub-model and a plant sub-model. The model accounts for the effect of meteorology, soil conditions, pesticide adsorption and volatilization. The soil model simultaneously resolves the soil profile of temperature, moisture, and pesticide concentrations to compute the time-dependent volatilization. The numerical model for soil treatment was in good agreement with an analytical solution at stagnant boundary conditions. The model performance of 14 pesticides against the analytical solution showed coefficient of determination (R2) values of 0.76 to 0.99 and index of agreement (IOA) values of 0.43 to 0.98. The soil model was also validated with observations at field conditions with variable meteorology. The time-dependent predicted volatilization compared well against measurements of two surface treated pesticides - metolachlor and triallate with R2 value of 0.4 and 0.7, respectively. The model prediction of the fumigant volatilization of 1,3-dichloropropene was in good agreement with the field observations (R2=0.8 and IOA=0.9). The plant model utilizes a simple resistance scheme with mass transfer of the pesticide on the leaf surface through a diffusive canopy boundary and an atmospheric boundary layer above the canopy. The model also accounts the loss of pesticide mass on the leaf surface due to penetration into leaf cuticle and photo-degradation as first-order kinetic rates. Volat (open full item for complete abstract)

Committee: Valerie Young (Advisor); Sumit Sharma (Committee Member); Guy Riefler (Committee Member); Michele Morrone (Committee Member); Jared DeForest (Committee Member) Subjects: Agricultural Chemicals; Agricultural Engineering; Atmospheric Sciences; Environmental Engineering; Environmental Science; Soil Sciences

Master of Science, The Ohio State University, 2019, Horticulture and Crop Science

In recent years, the increased demand for locally grown produce and outbreaks of E. coli linked to leafy greens has led to hydroponic leafy green production in controlled environments becoming a viable addition to the fresh produce food supply. Prevention of plant pathogen introduction in hydroponics is critical, as effective control agents for root diseases of edible crops are limited and may not be registered for use in greenhouses or indoors. This study examined lowering nutrient solution pH as a new management strategy to mitigate the risk of oomycete root disease incidence without negatively influencing plant growth. Although pH below 5.0 has been shown to negatively affect oomycete pathogen growth and reproduction, hydroponic nutrient solution is typically maintained within pH 5.5-6.5, as plants tend to exhibit growth inhibition outside of this range. Nevertheless, growth inhibition can typically be attributed to pH-dependent factors affecting nutrient uptake and availability, which may be mitigated if precautionary measures are considered. We hypothesized that if plants can be grown in pH below 5.0, the risk of oomycete disease incidence may be reduced. As first steps towards the development of a new nutrient solution management strategy, we determined if adjusting micronutrient concentrations in nutrient solution based on reported availability levels were effective in mitigating nutrient disorders and plant growth inhibition typically experienced at low pH. Basil and spinach plants were grown in deep-water hydroponic systems with pH maintained at 4.0, 4.5, 5.0, or 5.5. Two nutrient solutions (with and without micronutrient adjustments) were applied at each pH level, where concentrations of copper, zinc, manganese, and boron were decreased by one-half and molybdenum concentration was doubled in the adjusted solution. To our surprise, even though most elemental concentrations of leaf tissue decreased with decreasing pH, basil plant growth was not affected by (open full item for complete abstract)

Committee: Chieri Kubota PhD (Advisor); Sally Miller PhD (Committee Member); Michelle Jones PhD (Committee Member) Subjects: Agricultural Chemicals; Agricultural Economics; Agricultural Education; Agriculture; Horticulture; Plant Pathology

Master of Science (MS), Ohio University, 2019, Geological Sciences (Arts and Sciences)

Geochemical analysis was carried out on samples of environmental phases (water, sediments, and soils) from La Barra de Santiago estuary (El Salvador, Central America) and adjacent streams to understand the dynamics and possible environmental and health effects of heavy metals, nutrient and sulfate concentrations in the ecosystem. Physiochemical parameters such as nutrient concentration (Nitrate and Phosphate), oxidation reduction potential (ORP), dissolved oxygen (DO), conductivity, total dissolved solids (TDS), pH, temperature, Chloride, Iodide and sulfate concentrations were determined using spectrophotometric methods, while heavy metal analysis was carried out using ICP-MS. Multivariate statistical methods, including correlation analysis (CA) and principal component analysis (PCA) were applied to define the mutual relationships between these parameters. Low concentration of sulfate in the water and sediments suggest it is unlikely that sulfur contamination due to the eruption of Santa Ana volcano in 2005 could be causing the lack of macroinvertebrates in the region. Phosphate in sediments and soil samples has low variability in concentration probably due to buffering by the solubility of phosphate minerals, whereas Nitrate concentration in the sediment is higher than in soil samples. High nutrient concentration and chloride in the region with low DO (symptoms of eutrophication) suggest hypernutrification could be the driver for the lack of macroinvertebrates in the estuary. The statistically significant relationships between Sr, Rb and Cl, and between Sr, Rb and SO4, suggest a chemical contribution from marine sources for these elements, while correlation between Fe, Cu, Cd, Zn, Cr, Ce, Co and Al indicates inland input into the ecosystem for these metals. Lastly, results from sediment quality assessments using several pollution indices such as geoaccumulation index (Igeo), mean-ERM quotient, concentration factor (CF), pollution load index (PLI), and contaminatio (open full item for complete abstract)

Committee: Dina Lopez (Advisor); Gregory Nadon (Committee Member); Keith Milam (Committee Member) Subjects: Agricultural Chemicals; Aquatic Sciences; Biogeochemistry; Biological Oceanography; Chemical Oceanography; Earth; Ecology; Environmental Geology; Environmental Health; Environmental Science; Environmental Studies; Geochemistry; Geological; Geology; Marine Geology; Natural Resource Management

Bachelor of Science, Ashland University, 2019, Chemistry/Geology/Physics

Syrian rue (Peganum harmala), a desert plant native to the Middle East and southern Asia, has a long history of use in rituals and folk medicine. It was introduced into the United States in the 1920's and has become an invasive plant thriving in deserts of the southwest. Syrian rue produces six harmala alkaloids that have the potential to inhibit the growth of neighboring plants and negatively impact organisms living in soil near its roots. In order to better understand the toxic properties of these compounds toward other plants, the alkaloids released by Syrian rue in soil were measured using silicone tube microextraction, a technique developed in our laboratory. Silicone sequesters and concentrates lipophilic organic compounds, such as the harmala alkaloids. This method also allows for repeated sampling of the soil without disturbance. The compounds are extracted from the silicone and the concentration of each compound is measured using high performance liquid chromatography (HPLC). Harmine and harmaline can be detected by fluorescence detection down to 10 and 1 ng/mL, respectively. The spatial and temporal profiles of the dynamic release of harmala alkaloids in the rhizosphere were measured using various planting methods (pots of unique design) and variations of silicone probe designs. Silicone sheet probes show the spatial profile of harmine ranging from 11 ng to 46 ng released in soil. The toxic effect of the alkaloids to three dicot species (Amaranthus hypochondriacus, Rudbeckia hirta, and Lactuca sativa) was examined. Germination and growth studies in the presence of harmine and harmaline have shown that harmaline is more inhibitory to the plants than harmine. Amaranth root growth was decreased by 41% for 5 μg/mL harmaline and was not affected for 5 μg/mL harmine. Changes in amaranth root growth were seen at higher concentrations of harmine: root growth decreased by 53% at 100 μg/mL harmine. Similar results were seen in the other spec (open full item for complete abstract)

Committee: Brian Mohney Ph.D. (Advisor); Jeffrey Weidenhamer Ph.D. (Other) Subjects: Agricultural Chemicals; Analytical Chemistry; Chemistry; Soil Sciences

Master of Science, The Ohio State University, 2018, Environment and Natural Resources

Maize (Zea mays L.) is the principal food source for Eastern Africa's rising populations. In Morogoro Region, Tanzania, 56% of agricultural land is cropped with maize and 90% of its people are smallholder farmers. For these reasons, understanding the relationship between crop management decisions, agricultural soil quality, and maize yield is of critical importance. Field management practices were recorded during the November – January (short) rainy season crop, and the March – June (long) rainy season, and water use during the short rainy season. Soil samples were taken from each field in June 2017 and analyzed for soil quality parameters pH, total nitrogen (TN), soil organic carbon (SOC), bulk density (BD), texture, aggregate stability (AS), and penetration resistance. Analyses indicated that during both the short and long rainy seasons, maize production resulted in a lower pH than in vegetable production, or maize – cowpea intercrop. Fields which were cropped with maize in the long rainy season had higher clay content (Clay) than did those cropped with a maize – cowpea intercrop. Sand content (Sand) appeared to be higher in fields cropped with a maize – cowpea intercrop in maize in the long rainy season. Textural variation was accounted for a spatial gradient in soil series, which likely informed crop choice. Aggregate stability was found to be higher in fields cropped with maize in the short rainy season than with vegetable. TN, SOC, BD, silt content (Silt), and penetration resistance were not found to vary between iii crop management practice. Each soil quality parameter was entered into a linear regression model and a mixed effects model with long rainy season maize yields to determine the property's association with maize production. These analyses indicated that BD and sand concentration were negatively affecting maize yields while silt concentration, and to a lesser extent, SOC and AS were positiv (open full item for complete abstract)

Committee: Rattan Lal PhD (Advisor); Jeffory Hattey PhD (Committee Member); Stephen Culman PhD (Committee Member); Mark Erbaugh PhD (Committee Member) Subjects: Agricultural Chemicals; Agriculture; Agronomy; Soil Sciences

Master of Science, The Ohio State University, 2018, Environment and Natural Resources

The herbicide glyphosate (N-(phosphonomethyl) glycine) was first introduced in 1974 as a non-selective, broad spectrum, post-emergent agrochemical, branded under the trade name Roundup® and intended to control weed competition in agricultural farming. It gained large popularity and increased usage in 1996 with the introduction of glyphosate resistant soybean (Glycine max) cultivars and again in 1998 with resistant corn (Zea mays) cultivars. Its widespread usage has increased the concern of unknown long-term effects on the soil rhizosphere microbial community. In the same long-term context there is also increased concern over glyphosate's toxicity and accumulation of degradation products, notably aminomethylphosphponic acid (AMPA), which accounts for the majority of detected metabolites in the soil. Chapter one of this thesis will review the current literature on the toxicity and degradability of glyphosate and AMPA in the soil. In chapter two of this thesis a long-term glyphosate greenhouse experiment was designed with two main objectives, (1) determine the effects of long-term glyphosate application for three different glyphosate formulations on glyphosate resistant (GR) soybean rhizosphere microbial communities of two different soil managements, one with and one without a history of glyphosate exposure, and (2) use stable isotope probing (SIP) to identify possible glyphosate degrading microbial functional groups in these two soil managements. The objective of chapter three was to expand on chapter two by investigating the accumulation of glyphosate and AMPA in both the rhizosphere and bulk soil of the same long-term glyphosate greenhouse experiment. Research from a greenhouse study showed that repeated application of glyphosate increased the abundance of gram-negative microorganisms relative to a single application as detected by FAMEs. Likewise a field study also showed that repeated application of glyphosate increased Fusarium fungal colonization on both corn an (open full item for complete abstract)

Committee: Richard Dick (Advisor) Subjects: Agricultural Chemicals; Agriculture; Microbiology; Soil Sciences

Master of Science, The Ohio State University, 2018, Plant Pathology

Watermolds that affect soybean seed and seedlings contribute to significant losses each year due to reduced plant population and yield. In Ohio, Pythium and Phytophthora populations are diverse, with more than 30 species of Pythium being recovered from symptomatic soybean seedlings. This includes species of Pythium that were recently reclassified as Phytopythium. Fungicide seed treatments and host resistance are the main strategies to manage seedling diseases caused by watermolds in Ohio. The reduced sensitivity of watermold populations towards the current active ingredients in the market has led to an increased interest to identify and evaluate new active ingredients. The objectives of this study were to evaluate the efficacy of oxathiapiprolin alone or in combination with metalaxyl/mefenoxam or ethaboxam as a soybean seed treatment and the pathogenicity of Phytopythium mercuriale on three soybean cultivars with different levels of resistance towards watermolds. Oxathiapiprolin was evaluated through lab, greenhouse, and field-based studies at 14 different environments across Ohio. In amended agar plates inoculated with different species of watermolds, oxathiapiprolin significantly limited mycelial growth of Phytopythium helicoides, Phy. litorale, Phytopythium delawarense, Phy. mercuriale, Phytophthora sojae and Phytophthora sansomeana, but not Pythium torulosum, Py. ultimum var. ultimum, Py. lutarium, Py. attrantheridium, Py. inflatum, Py. oopapillum, Py. diclinum, Py. pleroticum, Py. heterothallicum, Py. nodosum, Py. middletonii and Py. dissotocum. In a greenhouse cup assay, there was no significant difference between the non-treated and seed treated with oxathiapiprolin (P > 0.05) that was inoculated with Pythium spp. In field based studies there was a significantly higher number of plants per hectare in 5 of 10 environments and yield (kg/ha) in 6 of 10 environments when seed of a moderately susceptible cultivar was treated with oxathiapiprolin alone or in com (open full item for complete abstract)

Committee: Anne Dorrance (Advisor); Melanie Lewis Ivey (Committee Member); Pierce Paul (Committee Member) Subjects: Agricultural Chemicals; Agriculture; Agronomy; Plant Pathology

Doctor of Philosophy, The Ohio State University, 2017, Food, Agricultural and Biological Engineering

Natural rubber (NR) is a raw material vital to the modern economy produced from a single plant species (Hevea brasiliensis) and the supply of which is insecure. Taraxacum kok-saghyz (TK) is an ideal rubber-producing crop because it synthesizes high quality rubber with similar composition, molecular characteristics, and mechanical properties to hevea NR. Extensive research on the development of TK as a commercially feasible crop is underway. Nonetheless, little research has been done on processing for the recovery of rubber, and byproducts. In this work, a comprehensive compositional analysis of field harvested TK roots was conducted to identify components that may have commercial value. Based on this analysis, new aqueous processes for the extraction of NR from TK roots that feature the use of alkaline pretreatment and enzymatic hydrolysis were investigated. Likewise, these processes were compared to wet milling treatments in order to identify those that result in NR of high purity, yield, and quality. Furthermore, alkaline pretreatment of TK roots at temperatures between 25 and 160°C, and NaOH loadings from 33 to 132 mg NaOH/g TK roots, was further studied to identify its impact on rubber yield, purity, and quality. Additionally, reliable methods to quantify primary TK root components were developed to allow the analysis of the large numbers of samples produced in the development of TK roots. The compositional analysis mass closure was greater than 95%. The roots contained 5.4% rubber and 1.7% resins. 60% of the root was hot water extractable. Inulin (18%) and proteins (10%) were the most abundant water-soluble fractions. Insoluble components included cellulose 9%, hemicellulose 7%, lignin 5%, protein 5% and pectin 3%. Based on the compositional analysis and current TK field plant density data, potential yields of various biobased products were calculated. Results indicated that TK is a potential source of NR and other products of importance such as inulin and prot (open full item for complete abstract)

Committee: Frederick Carl Michel (Advisor); Katrina Cornish (Advisor); Ajay Shah (Committee Member); Thaddeus Ezeji (Committee Member) Subjects: Agricultural Chemicals; Agricultural Engineering; Chemical Engineering; Engineering; Materials Science; Polymers

Master of Science, Miami University, 2017, Biology

For animals that live in association with humans, a key ecological question is how anthropogenic factors influence their behavior and life history. While major negative effects are obvious, subtle non-lethal responses to anthropogenic stimuli may provide insight into the features that lead to the success of species that thrive in habitats heavily impacted by humans. Here I explored the influence of the herbicide atrazine on the behavior and various life history traits exhibited by a wolf spider that is found in agroecosystems where this herbicide is commonly applied. In my first experiment, exposure to atrazine altered activity patterns of this spider. In my second experiment, exposure delayed maturation and increased the probability of spiders having a faulty molt. Atrazine also decreased the probability of producing an egg sac after mating, increased mass of egg sacs that were produced, and negatively impacted adult lifespans. These results suggest that the atrazine based herbicides that are routinely applied to agricultural fields result in altered behavior and life history traits of these spiders and may therefore influence the community of predators and their effects on the food web in complex ways.

Committee: Ann Rypstra Dr. (Advisor); Michelle Boone Dr. (Committee Member); Alan Cady Dr. (Committee Member) Subjects: Agricultural Chemicals; Biology; Ecology; Toxicology

Master of Science, The Ohio State University, 2016, Food Science and Technology

In a multi-component chocolate product, oil migration, from high oil content filling into the chocolate is one of the major contributors to quality loss. Five different cocoa butter samples were used to model and study the effects of chemical composition and processing conditions on oil migration. Samples were crystalized under two different processing conditions. Control samples were crystalized under 0 shear rate and 0.5 °C/min cooling rate. Processed samples were crystalized under 250s-1 shear rate and 4.5 °C/min cooling rate. Crystalized cocoa butter samples were placed in contact with a cream as a source of liquid oil. Using magnetic resonance imaging, the movements of liquid oil into samples were investigated. The sample oil diffusivity was analyzed based on the Fickian diffusion model. Slightly different chemical composition affected cocoa butter's melting point, solid fat content, microstructure, and resulted in different oil migration rate in the samples from five different origins. Additionally, processing conditions significantly retarded the oil migration rate in cocoa butter system. However, identical trends observed in control and processed samples indicated that different processing conditions would not eliminate the effects of chemical composition in cocoa butter on oil migration kinetics. Overall, minor differences in chemical composition of cocoa butters from different origins affect the oil diffusivity. Processing conditions can help slow down the rate of oil migration in cocoa butter system. However, it would not overcome the effects of chemical composition on oil migration kinetics.

Committee: Farnaz Maleky (Advisor); Melvin Pascall (Committee Member); Christopher Simons (Committee Member) Subjects: Agricultural Chemicals

Doctor of Philosophy, The Ohio State University, 1955, Biochemistry

N/A

Committee: Alvin Moxon (Advisor) Subjects: Agricultural Chemicals; Biochemistry

Doctor of Philosophy, The Ohio State University, 1955, Biochemistry

N/A

Committee: E.F. Almy (Advisor) Subjects: Agricultural Chemicals; Biochemistry

Doctor of Philosophy, The Ohio State University, 2015, Plant Pathology

Tomato is an economically important segment of agricultural production in the United States. Bacterial leaf spot (BLS) causes serious losses in tomato and pepper in the Midwest. Four Xanthomonas species cause BLS on these crops. In a four-year survey covering 16 counties in Ohio and one county in Michigan focused on the causal bacteria of BLS in processing tomatoes, fresh market tomatoes and peppers, a total of 240 strains were isolated, containing 169, 45, and 26 strains of X. gardneri, X. perforans, and X. euvesicatoria, respectively. The predominant species in processing and fresh market tomatoes was X. gardneri. Xanthomonas euvesicatoria was the most abundant species in peppers. Of all strains collected in this survey, 98%, 68% and 4% were insensitive to 30, 100, and 200 µg/ml copper sulfate, respectively. Bactericides and a plant resistance activator were evaluated for efficacy in reducing BLS disease intensity in the greenhouse and field. In a greenhouse simulating a commercial seedling production environment, both acibenzolar-S-methyl and aluminum Tris O-ethyl phosphate reduced bacterial populations relative to the negative control in one of the two trials. In the second trial, lower seedling density contributed to reduced BLS severity compared to higher seedling density. In field trials, both acibenzolar-S-methyl and isothiazolone in combination with the surfactant (Activator 90) significantly reduced the yield of fruits with BLS symptoms compared to the non-treated control in one of the two years of the study. The addition of Activator 90 improved the efficacy of acibenzolar-S-methyl and copper sulfate in reducing BLS on fruit in one of two years. However, fruits from plants treated with isothiazolone plus Activator 90 exhibited more large BLS lesions in one of the years than the non-treated control. The percentage of fruits with BLS symptoms, foliar BLS severity at the end of field experiment, and area under the disease progression curve for foliar BLS we (open full item for complete abstract)

Committee: Sally Miller (Advisor); Pierce Paul (Committee Member); Chris Taylor (Committee Member); David Francis (Committee Member); Peter Ling (Committee Member) Subjects: Agricultural Chemicals; Agriculture; Microbiology; Plant Pathology

Doctor of Philosophy, The Ohio State University, 2015, Microbiology

Atrazine is one of the most widely used herbicides in the world. It is primarily used in the production of corn in the United States. Although it may marginally increase crop yields, atrazine is also an endocrine disruptor in non-target organisms. Its moderate solubility in water allows for atrazine to contaminate surface and ground waters far removed from the point of application to soil. Although atrazine can be degraded abiotically, its primary mode of attenuation in natural environments is through bacterial degradation. Full mineralization of atrazine to CO2, H2O, Cl- and NH4+ has been demonstrated in Pseudomonas ADP, which contains the complete suite of atz atrazine catabolic genes. The overall hypothesis of this study is that the microorganisms and catabolic pathways reported in the literature do not universally account for the atrazine biodegradation observed in different natural environments. Furthermore, it is hypothesized that in situ pre-enrichment methods yield atrazine degraders uncultivable by classical laboratory enrichment, including anaerobic bacteria. The discovery of atrazine catabolic genes other than those in the atz pathway and the demonstrated involvement of consortia of bacteria in atrazine biodegradation suggest that the full diversity of environmental atrazine biodegradation has yet to be elucidated. In order to further elucidate the bacteria and genes responsible for atrazine biodegradation in different environments, locations with different exposures to atrazine were chosen for study. Among them were a farm location that was the site of multiple pesticide spill events throughout its history and a constructed wetland that receives river water containing agricultural runoff. Samples from these sites were assessed for atrazine biomineralization via biometer studies. In addition to traditional environmental sampling, these sites were also sampled with Bio-Sep beads to allow for in situ pre-enrichment for atrazine-degrading microbes. (open full item for complete abstract)

Committee: Olli Tuovinen PhD (Advisor); Michael Boehm PhD (Committee Member); Charles Daniels PhD (Committee Member); Michael Ibba PhD (Committee Member) Subjects: Agricultural Chemicals; Biology; Environmental Science; Microbiology; Molecular Biology