UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
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Item MY TRANS.PARENT WOMB: QUANTUM PLAY, ARTIFICIAL INTELLIGENCE, AND ASEXUAL REGENERATION FROM WITHIN THE US WAR MACHINE(2024) Leizman, Danielle; Collis, Shannon; Art; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)"FROM BENEATH" is a multimedia art installation which offers an immersive experience through three distinct works that act as “wombs.” The work aims to redefine conventional ideas of reproduction and futurity by transforming the gallery space into a realm of sensory exploration and non-linear time. Utilizing devices such as optical illusion, tactile sound, AI generation, and re-animation of archival media, the work advocates for embodiment as a catalyst for a queer navigational strategy which the artist defines as “quantum play.”Item "It's Not Like I Can Just Pause Diabetes:" How People Living with Type 1 Diabetes Navigate Relationships, Reproduction, and Parenting(2023) Maietta, Justin T.; Doan, Long; Cohen, Philip N.; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation draws on 26 qualitative in-depth interviews to explore how people who live with type 1 diabetes (T1D) navigate three important and intimate areas of life: dating and relationships, reproduction, and parenthood. Applying a sociological disability framework to this research, I explore how participants’ trajectories and outlooks, decisions, and feelings of agency and self-efficacy in these areas of life are influenced biographically, structurally, and culturally on account of living with T1D. Each of the three substantive chapters of this dissertation is an article that examines the relationship between living with T1D and either dating and romantic relationships, reproduction, or parenthood. First, I argue that dating and relationship norms and expectations can be rooted in ableist ideals that marginalize potential partners living with impairment or disability. I also demonstrate the importance of two kinds of support that dating partners offer to participants living with T1D: tangible support and incorporative support. Both kinds of support work against assumptions made about dating and relationships among people living with impairment or disability. I then examine facets of living with T1D occurring at multiple analytical layers (structural and cultural, interactional, self, and body) across the life course and how they influence whether people with T1D feel having children is something they want or need or is within their reach. This article enriches our understanding of disability by demonstrating that individuals with less noticeable or visible disability are subject to similar social imperatives of risk management and moral reproduction as those with more noticeable physical or sensory disabilities. Finally, I discuss how participants think about and practice balancing caring for their T1D and caring for their children, as well as how they reconceptualize “good parenting” within an intensive parenting culture that expects child-centered and self-sacrificing parenting. I also discuss how adults who grew up as children and adolescents with T1D reflect on how they have been and continue to be parented regarding their T1D, leading them to challenge norms of “expert-guided” parenting within an intensive parenting culture. This challenge is made through advocating for more agency, autonomy, and expertise grounded in embodied experience to be afforded to children and young adults with T1D in ways that supersede the expertise of doctors and researchers. Overall, this dissertation illustrates: (1) how experiences, interpretations, and representations of disability at multiple analytical levels have the power to remove some feelings of agency and self-efficacy from disabled people throughout the process of reproduction, in their dating lives and romantic relationships, and in their roles as parents; and (2) the ways that individuals with disability adapt to, challenge, and disrupt the norms, ideologies, and assumptions that marginalize them in these intimate areas of life.Item ANALYSIS OF THE ROLE OF PRDM14 IN PLURIPOTENCY AND SPECIFICATION OF THE GERM CELL NICHE IN THE DOMESTIC PIG(2018) Sandmaier, Shelley; Telugu, Bhanu; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The generation of functional, mature germ cells in order to pass on its genetic information to the next generation is of paramount importance to a species’ survival. As a result, primordial germ cells (PGC), the precursor cells that give rise to mature spermatozoa or oocytes, are one of the first cell types to be specified and induced in the early mammalian embryo. In mammals, this process happens during the primitive streak stage of development and PGCs continue to proliferate as they migrate from the posterior end of the embryo through the hindgut and settle in the future gonadal region. One gene in particular, PRDM14, is required for PGC specification in the mouse, but its function was unknown in the domestic pig (Sus scrofa). This dissertation project sought to determine the role of PRDM14 in the porcine germ cell program as well as in early embryo development. The first study used the mouse as a model using CRISPR/Cas9 technology to direct pluripotent stem cells toward the germ cell pathway by aggregation with a host embryo that was unable to form PGCs. Chimeras generated by this technique exhibited 100% occupation of the germline by donor control stem cells. In the second study, mRNA transcripts for a suite of germ cell-related genes were analyzed to determine their expression in various stages of the early porcine embryo: from zygote to blastocyst and embryonic day 28. Unlike in the mouse and human systems, several genes that were predicted to be expressed in the early embryo (PRDM14, TET1, and PRDM1, among others) were found to be extremely low in abundance. In the final study, the function of PRDM14 in the pig was disrupted using gene editing, and the resulting phenotype was characterized. Loss of PRDM14 does not seem to be critical for the specification of PGCs in the domestic pig, as evidenced by the existence of germ cells following knockout. Together, these studies have applications for spermatogonial stem cell transplantation technology in order to expand the genetic reach of superior animals by producing animals whose germ cells are derived from a genetically valuable donor.Item The Effect of Depression on Women's Contraceptive Behaviors and Teenage Pregnancy(2018) Vafai, Yassaman; Steinberg, Julia R.; Family Studies; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Objective: The overall objective of this dissertation was to investigate the effect of depression on women’s contraceptive behaviors and teenage pregnancy. Methods: In the first study, the relationship between pre-abortion depressive symptoms and effectiveness level of contraceptive method chosen (low, moderately, or highly effective) after contraceptive counseling was examined using multinomial logistic regression in a group of women seeking abortion services. In the second study Cox proportional hazards models were used to estimate the hazard of contraceptive method discontinuation and unintended pregnancy among women experiencing any current and past elevated depressive symptoms in reproductive health settings. The third study examined the association between first depressive episode relative to age at first sex, and the hazard of first teenage pregnancy among girls participating in the National Comorbidity Survey–Adolescent Supplement. Results: More pre-abortion depressive symptoms were associated with higher odds of choosing a low contraceptive method than a moderately or a highly effective contraceptive method. Compared to non-depressed women, women exposed to baseline and a history of elevated depressive symptoms and those exposed to a history of elevated depressive symptoms had 39% and 12% increased hazards of contraceptive method discontinuation respectively; though the associations were not statistically significant when examining all contraceptive methods together. These associations were significant among patch and the injectable users. Finally, adolescent girls whose first depressive episode occurred at the same age as their sexual debut had a higher likelihood of experiencing first teenage pregnancy (HR: 2.73, 95% CI 1.07, 6.97) than those experiencing no depression onset. Conclusion: This dissertation provides evidence for the critical role of timing of depression in determining women’s contraceptive behaviors and reproductive decisions. The findings collectively suggest that not only the presence or absence of depression, but also the time the condition manifests itself during the course of women’s live can predict women’s decisions surrounding contraceptive method choice, continuation, and pregnancy. Implications: The integration of mental and reproductive health as well as a more effective patient-physician communication are warranted in an effort to optimize pregnancy outcomes in women at risk for depression.Item STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF THE PANAMANIAN GOLDEN FROG (ATELOPUS ZETEKI) SPERMATOZOA – IMPACT OF MEDIUM OSMOLALITY AND CRYOPRESERVATION ON MOTILITY AND CELL VIABILITY(2015) Della Togna Nieto, Gina; Dinman, Jonathan; Comizzoli, Pierre; Molecular and Cell Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The Panamanian Golden Frog (Atelopus zeteki, Anura: Bufonidae), an endemic species from Panama, is critically endangered and believed to be extinct from the wild. Infectious disease, habitat destruction and pet trade are among the major causes of the populations decline. Conservation initiatives in Panama and the US have established captive breeding programs for the species but there is still much to be learned about its reproductive physiology to manage and sustain populations using Assisted Reproductive Technologies (ARTs). The main objectives of this dissertation were: 1) characterize the general sperm parameters and assess the effect of hormonal stimulation on motility, forward progressive motility, DNA integrity, sperm morphology and seasonality; 2) identify the effect of extracellular conditions, mainly dilution and temperature, on motility, forward progressive motility, duration of motility, morphology and DNA integrity; and 3) evaluate the effect of cryoprotectants on motility, forward progressive motility and sperm DNA integrity before and after freezing. Results demonstrated that: 1) A. zeteki sperm morphology is similar to that described in other Bufonids; the species successfully produces high quality spermatozoa when stimulated with intraperitoneal injection of Amphiplex, GnRH and hCG; hormonal stimulation is not detrimental to the motility parameters, cell morphology or DNA integrity; and, there is no seasonal effect on the response to the hormonal stimulation. These results indicate that the use of hormone treatments can be included in captive breeding programs to safely collect good quality sperm; 2) dilution of spermic urine in water highly reduces sperm motility, forward progressive motility, DNA and morphological integrity while storage of spermic urine at 4 °C preserves sperm quality for at least 46 min after collection; and 3) some recovery of viable A. zeteki spermatozoa after cryopreservation can be achieved by equilibrating the ARS-diluted samples for 5 min at 4 °C in CPA3-REY, using step-wise cooling before plunging the samples in LN2. Collective results offer missing information on the reproductive biology of the male A. zeteki and lead to the application of ARTs for the captive management of this charismatic but critically endangered species.Item Investigation of spermatozoal metabolism and substrate utilization in domestic and non-domestic felids(2015) Weiner, Halli Sigal; Keefer, Carol L; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cryopreservation of spermatozoa is a critical aspect of assisted reproduction. However in most cases, this process causes diminished spermatozoal function and low cellular survival. The effects of cryopreservation are further compounded in spermatozoa from individuals with disorders known to affect fertility. Teratospermia, characterized by the ejaculation of >60% morphologically abnormal spermatozoa, is one such disorder. Sperm from individuals with this condition exhibit reduced motility, impaired mitochondrial function, and a reduced ability to bind, penetrate, and fertilize an oocyte compared to sperm from normospermic males. Interestingly, even spermatozoa from teratospermic males that appear normal exhibit reduced functional capacity and following cryopreservation all cells are further impaired. More than 90% of felid species are affected by this condition, and it is prevalent among humans. Previous research suggested that impaired sperm metabolism in cheetahs – a ubiquitously teratospermic species – contributes to their poor cryosurvival and function, but the specific mechanisms are unknown. In this research, we hypothesized that inherent differences exist between the substrates and metabolic pathways utilized by sperm from normospermic and teratospermic individuals and on a species-specific basis. Gas chromatography - mass spectrometry (GC-MS) was used to investigate felid sperm metabolism using semen collected from domestic cats (Felis catus), cheetahs (Acinonyx jubatus), and clouded leopards (Neofelis nebulosa). The main objectives of this research were to: 1) characterize the metabolome of spermatozoa and seminal fluid; 2) investigate the role of β-oxidation in sperm motility and metabolism; and 3) interrogate the significance of specific metabolic pathways using metabolic activity profiling and heavy isotope tracers. Using GC-MS enabled the identification of metabolites which were unique to each species and sperm status (normospermic vs. teratospermic). Additionally, treatment of sperm with a β-oxidation inhibitor caused impaired motility in cheetah - but not domestic cat or clouded leopard - spermatozoa. Finally, fluxomic analysis demonstrated that glucose, fructose, and pyruvate are metabolized by felid sperm, but pathway utilization is species-specific. This is the first study to utilize a metabolomic and fluxomic approach to studying felid sperm, and the results of these studies illustrate the complexity of sperm metabolism on a species-specific basis. Understanding metabolic pathway activity in these cells will aid in the development of improved assisted reproduction techniques that may better facilitate sperm function and survival.Item MULTIDISCIPLINARY APPROACH TO UNDERSTANDING THE POOR REPRODUCTION IN THE WHOOPING CRANE (GRUS AMERICANA)(2013) Brown, Megan Elizabeth; Songsasen, Nucharin; Keefer, Carol L; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Reproductive success of the endangered whooping crane (Grus americana) maintained ex situ is suboptimal. The main goals of this multidisciplinary investigation are to advance the understanding of whooping crane reproduction and identify potential causes of poor reproductive success in a captive colony. The specific objectives include (Study 1) determining overall seminal characteristics and examine the influences of inbreeding, age, and stages of breeding season on seminal quality in captive birds and (Study 2) utilizing non-invasive endocrine monitoring to longitudinally assess gonadal and adrenal steroids of bird pairs with various reproductive outcomes and evaluating the relationship between hormones and crane behaviors. Our findings demonstrate that (1) there is no relationship between inbreeding coefficient or age and seminal quality of the whooping crane and (2) stage of breeding season impacted seminal output and characteristics. Overall estradiol concentrations and reproductive behaviors, but not glucocorticoid levels, were also key determinants to successful reproductive output.Item COSTS AND BENEFITS OF COOPERATIVE INFANT CARE IN WILD GOLDEN LION TAMARINS (LEONTOPITHECUS ROSALIA)(2009) Siani, Jennifer Marie; Dietz, James M.; Behavior, Ecology, Evolution and Systematics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In cooperative breeding species, nonbreeding individuals typically delay dispersal, forego reproduction and provide care to infants that are not their own. All caregivers must therefore balance infant demands against their own self-interests. In this dissertation I investigate the costs and benefits of cooperative infant care in wild golden lion tamarins (Leontopithecus rosalia) . In chapter 1, I examine what factors influence the distribution of infant care to clarify why helpers contribute care to infants. I find that reproductive status strongly influences infant caretaking patterns, with parents contributing significantly more infant carrying and food provisioning than helpers. Parental dominance in caretaking and the lack of variation in infant carrying or food transfers with caregiver age, sex or condition suggests that genetic relatedness dictates these caretaking decisions, with infant behavior also influencing food provisioning. In chapter 2, I investigate the effects of gestation and infant care on activity budgets and body mass to determine if infant care results in detectable short-term costs to caretakers. Tamarins are hypothesized to require assistance from nonreproductive helpers in raising offspring due to ecological (e.g. predation risk, foraging) and energetic costs of gestation and care of infants, usually twins. During gestation, reproductive females do not make behavioral changes that suggest an energy conservation strategy; however, all caregivers make behavioral changes while carrying infants to increase predator awareness and decrease energetic expenditure and are able to maintain a stable body mass throughout infant care. Cooperative infant carrying may allow individuals to balance energetic demands and mitigate predation risk, thus supporting the hypothesis that energetic costs have driven the evolution of cooperative caretaking. In chapter 3, I present the results of an acoustic playback experiment to determine the frequency and intensity of caregiver responses to infant begging vocalizations. Caregiver responses were influenced by reproductive status, sex, condition, experience, group size and activity level, but not familiarity or genetic relatedness. The variation in caregiver responses to infant vocalizations suggests that these responses are flexible and dynamic, shifting with changes in group composition and context and with individual reproductive status and physical condition.Item The Gonadotropin Releasing Hormone-3 System in Zebrafish: Early Development and Regulation(2008-12-15) Abraham, Eytan; Zohar, Yonathan; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The objective of this study was to expand our understanding of the early development of forebrain Gonadotropin Releasing Hormone (GnRH) neurons in vertebrates in general and in fish in particular. The correct migration during early development of the hypophysiotropic GnRH neurons from the olfactory region to the hypothalamus is crucial for normal gonadal development and reproduction. We developed a Tg(GnRH3:EGFP) zebrafish line in which EGFP is specifically expressed in GnRH3 neurons. Using this line, we have studied in detail the early spatiotemporal development of the GnRH3 system in vivo. In addition, we have studied various factors, including GnRH3, Netrins and Hedgehog to better understand some of the mechanisms that mediate this complex axophilic neuron migration event. Lastly, we have conducted targeted GnRH3 neuron ablation experiments in view of determining the embryonic origin of POA-hypothalamic GnRH3 neurons and the effect of lack of GnRH3 neurons in the CNS. Our findings show that: 1) GnRH neurons first differentiate and express GnRH3 at 24-26 hours post fertilization (hpf) and immediately thereafter begin to extend fibers. 2) GnRH3 neurons project a complex network of fibers, prior the GnRH3 soma migration, to various CNS regions, and to the pituitary. 3) GnRH3 soma begin migrating towards the hypothalamus at 3 days post fertilization (dpf), passing through the terminal nerve (TN), lateral telencephalon, and reaching the hypothalamus by 12 dpf. 4) expression of GnRH3 itself is necessary for the normal early differentiation and fiber extensions of GnRH3 neurons. 5) Netrin1a is directly involved as a chemoattractant in GnRH3 fiber organization and subsequently, in GnRH3 soma migration to the hypothalamus. 6). Netrin2 is required for normal early ZF embryogenesis. 7). Sonic hedgehog a does not serve as a specific factor in the development of the GnRH3 system. 8). GnRH3 neuron regeneration capacity is temporally limited. 9). Successful ablation of olfactory GnRH3 neurons during development results in lack of GnRH3 neurons in the entire sexually mature brain as well as abnormal gonadal development and inability to reproduce. This study expands our understanding vis-à-vis the early events that occur during GnRH3 system development and that regulate this complex process. In a broader sense these findings augment current knowledge regarding the regulation of long range tangential neuron migration during development.