Doctor of Philosophy, The Ohio State University, 2023, Horticulture and Crop Science

Global climate change poses significant challenges to agriculture, accelerating the risk of drought. Identifying sources of tolerance or avoidance to the stress associated with drought is imperative for crop improvement. Chile pepper (Capsicum sp.) is a culturally and economically important food, spice, and medicine worldwide. At one of its centers of domestication and diversity, Mexico, wild, semi-wild, and landrace populations are found across environmental gradients and cultivation systems. Thus, Mexico provides an excellent opportunity to study local adaptations associated with drought across scales of domestication and environment. In the following dissertation, I explore the morphophysiology, ecology, and genetic variation of drought adaptation through extensive phenotyping under induced soil water deficit across chile pepper germplasm from Mexico and the US. Through four research chapters concentrating on different germplasm, phenotypic responses, and growth stages, I quantify effects of soil water deficit on chile pepper and identify possible drought adaptations and mechanisms of water deficit tolerance and avoidance. Results of this work lay a foundation for exploring chile pepper germplasm specifically for drought adaptations, highlight unique phenotypic responses and accessions for further study, and improve ability to efficiently phenotype under water deficit.

Committee: Kristin Mercer (Advisor); Darren Drewry (Committee Member); David Francis (Committee Member); Leah McHale (Advisor) Subjects: Agriculture; Ecology; Horticulture; Plant Sciences

Master of Science, The Ohio State University, 2022, Comparative and Veterinary Medicine

Pseudomonas syringae pv. syringae (Pss) is an emerging seed-borne pathogen that causes Pseudomonas leaf spot (PLS) disease in bell peppers. It causes severe necrotic lesions on pepper leaves that can spread to 50-80% of the field under favorable environmental conditions. PLS can cause significant economic losses to pepper production if the disease is left uncontrolled. However, not much is known about the genes that Pss carries to be able to cause disease in peppers. It is important to understand the virulence genes that Pss carries so that appropriate measures can be developed to control Pss in peppers. Therefore, part of my research aimed to use comparative genomic analysis to understand the genes in Pss that are important for virulence in pepper seedlings. The Pss strains (n=16) evaluated showed varying levels of virulence (disease severity and Pss population) at 3-, 7-, and 14-days post-infection (dpi) on the susceptible 'California Wonder' pepper variety in a controlled growth chamber environment. The Pss strains also displayed varying growth, biofilm development, and motility in vitro in M9 minimal broth at 28˚C, however, the variation in in vitro performance did not explain the variation in the virulence of the Pss strains in pepper seedlings. Whole genome sequencing was performed on these Pss strains. The genes were functionally characterized, and core genomes were separated from the variable genomes between the Pss strains. A total of 812 genes were variable among the Pss strains including known virulence genes. Additionally, a multivariate correlation analysis identified 285 genes that were significantly correlated to the virulence of Pss in pepper seedlings (r2 of  0.5 to 0.675; P<0.01). The genes that were significantly correlated with the virulence of Pss strains included known virulence genes associated with motility (n=2), biofilm (n=5), and Type III and VI secretion systems (T3SS and T6SS) (n=9). Further, the two strains (SM156-18 and SM226-1) that (open full item for complete abstract)

Committee: Gireesh Rajashekara (Advisor); Sally Miller (Committee Member); James Fuchs (Committee Member) Subjects: Biology; Microbiology; Plant Pathology

Doctor of Philosophy (PhD), Ohio University, 2020, Mass Communication (Communication)

The arrival of the internet and its related platforms have created feminist communities in the virtual world in western countries and these phenomena have extended to the African continent. This study investigates the Ghanaian-based feminist movement, Pepper Dem Ministries (PDM), the group's activities on social media, and how it is utilizing the platform to propagate its feminist agenda. Specifically, this research focuses on Pepper Dem Ministries' cyberfeminists' articulations on Facebook platform and the group's contribution to the politics of feminism in Ghana. The study is premised on three grounds: first, the perceived democratic nature of digital media platforms has afforded minority groups, particularly women, space to engage their feminists' politics and contribute to global feminist discourse; second: that scholarly work on cyberfeminists practice is heavily skewed towards Western cyberfeminist groups thereby alienating African cyberfeminist groups; and third, that consequent upon the latter, there is the urgent need to draw attention to African cyberfeminist practices, show how they negotiate their space within the digital space and eventually mainstream their feminist voices into the global feminism discourse. The study is anchored on Black cyberfeminist theory which draws on intersectional studies and Black feminists thought to interrogate how black cyberfeminists construct their identity on digital media platforms. The study is further positioned on post-colonial feminists' articulations and African feminists theories that provide a lens of interpretations for Pepper Dem Ministries' feminist positionality and practice. Utilizing feminist cyberethnography as a methodological standpoint, the study found that social media has provided new spaces for African feminist movements such as the PDM to openly articulate their otherwise muted voices leading to initiation of fresh discourses on hitherto uncontested masculinecentered spaces and issues. Members of P (open full item for complete abstract)

Committee: Steve Howard (Advisor) Subjects: African Studies; Gender; Mass Media; Womens Studies

Master of Science, The Ohio State University, 2017, Horticulture and Crop Science

Root systems are known to have profound influences on nearly every aspect of plant development and biology, including vegetative and reproductive capacity. However, the specific impacts of intra-specific combinations of root and shoot systems, when combined in physical hybrids, on important physical, chemical, and sensory properties of Capsicum annumm pepper fruit are largely unknown. Grafting was used to combine the canopy and root system of two types of Capsicum plants (producers and non-producers of capsaicin and small, more elongated versus large, blocky fruit), thereby making it possible to examine the separate and combined roles of variety-specific roots and shoots in shaping key fruit characteristics, among them the concentration of capsaicin. Capsaicin is an ideal metabolite to study root-shoot interaction and roles because early stages of its biosynthetic pathway occur in the roots, with final assembly in the fruit at advanced stages of development. Fruit size, shape, wall thickness, and soluble solids levels were similarly tracked as they and capsaicin influence consumer acceptability and fruit marketability. The overall program involved field studies in 2016 and 2017, a targeted wintertime greenhouse study, and consumer sensory analysis. Overall, it was found that the Capsicum variety supplying the root system of the grafted plant had little influence on the variables measured when a sweet pepper was used as a scion. When a hot pepper was used as a scion the root system played a large role in influencing the capsaicinoid profile of the fruit. Implications of this finding include: a) that the variables measured are influenced by more than the root systems used here and b) that it may possible to employ rootstock-scion combinations without concern over rootstock influence on fruit in commercial production.

Committee: Matthew Kleinhenz (Advisor); Joseph Scheerens (Advisor) Subjects: Biology; Botany; Food Science; Horticulture

Doctor of Musical Arts, The Ohio State University, 2016, Music

Bright Sheng is one of the most accomplished Chinese-American composers in North America, Europe, and Asia. His compositions cover various performance genres from opera to ballet, symphonic works to chamber music, solo works to innovative ensemble pieces. Bright Sheng's works often combine the strong influence of Chinese folk music with traditional Western compositional techniques. His music has melodious musical lines, impulsive rhythmic drives, and dramatic mood changes. Hot Pepper for Violin and Marimba (2010) is one of Bright Sheng's recent chamber works featuring the violin. Although he has acknowledged Chinese folk music influence in his early works, the composer has only provided vague information about the Chinese folk elements in Hot Pepper. This document describes different types of Chinese folk music in order to help performers who may not be familiar with Chinese music interpret the work properly. Chapter one offers background information about the composer. Chapter two represents an evolutionary outline of Bright Sheng's compositional style by briefly examining H'un (1988), The Stream Flows for Solo Violin (1990), and Three Fantasies for Violin and Piano (2005). Chapter three provides an analysis of the form and tonality in Hot Pepper and concludes with a discussion about how to understand the relevant Chinese folk music that relates to Hot Pepper and make interpretive decisions based on the study.

Committee: Kia-Hui Tan (Advisor); Juliet White-Smith (Committee Member); Alan Green (Committee Member) Subjects: Music

MS, Kent State University, 2013, College of Arts and Sciences / School of Biomedical Sciences

Parkinsonism is a neurodegenerative disease that mostly affects elderly people. Monoamine oxidase B (MAO-B) inhibitors have been used in the symptomatic treatment of motor symptoms of parkinsonism. Selective MAO-B inhibitors have also been shown to be neuroprotective agents. Using piperine, a natural alkaloid obtained from black pepper plant as lead compound, we initiated a virtual screen to identify novel selective MAO-B inhibitors. Twenty compounds were tested in several enzyme assays, with compounds 5223890 and 7691778 showing the most potent MAO-B inhibition. MAO-B IC50 for compounds 5223890 and 7691778 were found to be 286 nM and 599 nM, respectively. These compounds were also screened for antioxidant activity in the oxygen radical absorbance capacity (ORAC) assay and both of them have shown a mild to moderate antioxidant capacity which can increase their neuroprotective effects. Pharmacokinetic high-throughput studies using parallel artificial membrane permeability assay (PAMPA) and bovine serum albumin (BSA) binding assays indicated that these compounds will likely cross the blood-brain barrier and will moderately bind to serum albumin. Several studies have shown that the prevalence of mild cognitive impairment in patients with parkinsonism is about 30% .Interestingly, four of the tested compounds showed mild to moderate acetylcholinesterase inhibition activity .Compound F5123-0122 has shown the most potent inhibitory effect on acetylcholinesterase activity (AchE IC50 of 35.2 micro-Molar). These compounds may be useful for treating parkinsonism with comorbid mild cognitive impairment.

Committee: Werner Geldenhuys Ph.D. (Advisor); Altaf Darvesh Ph.D. (Committee Member); Richard Carroll Ph.D. (Committee Member) Subjects: Biomedical Research; Neurosciences; Pharmaceuticals; Pharmacology; Pharmacy Sciences