Biological Sciences Masters Theses

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Aging and Early Life Stress: Telomerase Dynamics and The Consequences for Telomeres in a Wild Bird
(North Dakota State University, 2020) Vangorder-Braid, Jennifer Teresa
Aging is an underlying risk factor for many major diseases including cancer, cardiovascular disease, and neurodegeneration. Yet we still do not know the full extent of how our bodies age and what determines our lifespan. One mechanism that may play an important role are telomeres, which are protective caps at the end of chromosomes. Telomeres are directly linked to longevity and can be lengthened by the enzyme telomerase. Early life telomere length is critical for lifespan, but we do not know how telomerase performs during this period. Whether variation in telomerase levels can influence telomere length and loss during development with consequences to longevity is still unknown. This thesis focuses on the role of telomerase during post-natal development and its response to stressors and activators with effects on telomeres. Taken together this research enhances our understanding of how telomerase acts and influences telomere during post-natal development.
Assessment of Blackbird Damage to Sunflower and Corn Fields in the Prairie Pothole Region of North Dakota
(North Dakota State University, 2011) Klosterman, Megan Elise
North Dakota is the top sunflower producing state in the United States, annually harvesting about 405,000 ha (1 million acres). Up to 63% of this crop is grown in central North Dakota in an area known as the Prairie Pothole Region (PPR). Since the early 2000s, com also has become a major crop in the PPR due to the development of hybrids for northern crop areas and increases in com prices. Blackbirds (Icteridae) can cause significant damage to both ripening com and sunflower. It has been three decades since a comprehensive sunflower damage survey was conducted in the PPR. I assessed blackbird damage to ripening sunflower and com in 120 randomly-selected plots during three growing seasons, 2008-2010. Damage was analyzed across four strata (Northeast Drift Plains, Northwest Drift Plains, Southern Drift Plains and Missouri Coteau) within the PPR. Landcover was analyzed to determine possible variables (pasture, com, sunflower, open water, wetland, small grains, developed, wooded, beans and other) related to blackbird damage. Stepwise logistic regressions were performed along with AIC model selection to determine significant (p<0.1) independent variables related to sunflower and com damage. Average damage to sunflower (2.14%) was higher than damage to com (0.33%), with sunflower in the Southern Drift Plains having the greatest levels of damage (11.11 %). Beans and wetland showed the greatest significance in relation to sunflower damage (p=<0.001, p=0.035), according to the selected AIC model. The most significant landcover variables surrounding damaged corn fields was open water (p=0.022), showing an increase in damage, and pasture (p=0.056), showing a decrease in damage. The results of this study provide data to help producers make informed decisions about crop selection and location.
Characterization of Variation in Growth Performance in Inbred Strains of Zebrafish (Danio Rerio)
(North Dakota State University, 2012) Meyer, Ben Michael
Although zebrafish have been a widely utilized model organism for several decades, there is little information available on physiological variation underlying genetic variation among the commonly used inbred strains. This study evaluated growth performance in response to fasting in six zebrafish strains [AB, TU, TL, SJA, WIK, and petstore (PET) zebrafish]. Fasting resulted in a decrease in whole blood glucose levels in PET, TL, and TU strains and did not affect glucose levels in AB, SJA, and WIK strains. Similarly, fasting had no effect on myostatin mRNA levels in AB, PET, TU, and WIK strains, but decreased myostatin-1 and -2 mRNA levels in SJA zebrafish. Fasting increased myostatin-2 mRNA levels in TL zebrafish. These data demonstrate that growth performance variation is present between commonly used zebrafish strains and can help future research endeavors by highlighting the attributes of each strain so that the most fitting strain may be utilized.
Characterizing the Immune Response of the Alfalfa Leafcutting Bee throughout Pupal Development
(North Dakota State University, 2015) Cummings, Sara Elizabeth
Megachile rotundata is a solitary cavity nesting bee that is the primary commercial pollinator of alfalfa in North America. During prepupal to adult development, they may be exposed to fungal, parasitic, and bacterial pathogens. However, little is known about their immune function throughout pupation. We characterized functional immunity of M. rotundata across development stages. We injected prepupal, pupal, and adult bees with live E. coli and compared mortality across groups. We also developed an assay to measure antimicrobial peptide (AMP) activity in hemolymph for the same age groups. Both pupal and prepupal bees are sensitive to injected E. coli, resulting in high mortality, while adult bees survived longer after infection. Pupal bees had significantly less AMP activity compared to prepupae and adults. Understanding immunity of M. rotundata will provide context for improving commercial rearing practices, where measuring AMP activity can now serve as a biological marker of bee quality.
The Conservation of Variation in Gryllodes sigillatus and Closely Related Cricket Species
(North Dakota State University, 2020) Dalos, Jeremy David
The ability to adjust behaviors to a particular environment has been well documented across taxa. Our understanding of behavioral plasticity is largely based on experiments in which individuals have a single exposure to an environment. Observed behavioral changes are then traditionally measured in small windows of responsiveness in a single population or species. In this project I investigated the effects of prolonged exposure to predator cues in Gryllodes sigillatus and also tested for the presence of trans-generational effects of this prolonged exposure. I found there were no differences in anti-predator behaviors when measured in subsequent assays compared to control individuals. These results were paired with a comparison of differences in average expressions of behaviors, differences in variances, and behavioral correlations of five closely related cricket species, including G. sigillatus. Our results showed that species differ in average behaviors and plasticity but did not significantly differ in behavioral correlations.
Development of the Stress Response in Fast (Coturnix Japonica) Versus Slow (Callipepla Gambelii) Growing Species
(North Dakota State University, 2012) Gastecki, Michelle Lynn
In this study, we evaluated the development of stress response in (1) two different species of quail, one species that is relatively fast-growing (Japanese quail, Coturnix japonica) and one that is relatively slow-growing (Gambel’s quail, Callipepla gambelii) and (2) two strains of a single species, the Japanese quail (wild-type and domesticated), that differ considerably in final size. Our data indicate that wild-type Japanese quail and Gambel’s quail have experienced trade-offs between growth and the stress response (e.g. Gambel’s quail have slower growth rates, but greater levels of CORT). However, the domesticated strain of Japanese quail used in this study seem to violate some predictions based on the life history theory (e.g. the domestic strain has faster growth rates and greater levels of CORT). The data in this study contribute to the understanding of differences in the stress response between species that exhibit different life history strategies.
Diet and Effects of Environmental Stressors on the Altricial Nestlings of Double-Crested Cormorants (Phalacrocorax Auritus)
(North Dakota State University, 2014) Randa, Jacob G.
Double-crested cormorants (Phalacrocorax auritus) are a common species of altricial waterbird found across much of North America. As a piscivorous colonial waterbird, cormorants are often persecuted due to perceived impacts on fisheries. In this study I examined the diet of cormorant nestlings at five cormorant colonies in central North America to answer two questions: 1) Is nestling diet reflective of opportunistic feeding behavior, thus diminishing the likelihood of negative impacts to the fishery? and 2) How do diet and environmental stressors effect the development of cormorant nestlings? By analyzing the caloric content of nestling diet and quantifying environmental stressors such as endoparasite and ectoparasite loads, I found diet was a significant contributor to structural long bone growth in both the wing and tarsus. Diet analysis also corroborated the long held belief that cormorants have highly variable diets reflective of local fish communities and may vary annually as fish assemblages change.
Drawing on Student Knowledge in Human Anatomy and Physiology
(North Dakota State University, 2014) Slominski, Tara
Prior to instruction, students may have developed alternative conceptions about the mechanics behind human physiology. To help students re-shape these ideas into correct reasoning, the faulty characteristics reinforcing the alternative conceptions need to made explicit. This study used student-generated drawings to expose alternative conceptions Human Anatomy and Physiology students had prior to instruction on neuron physiology. Specifically, we investigated how students thought about neuron communication across a synapse (n=355) and how neuron activity can be modified (n=311). When asked to depict basic communication between two neurons, at least 80% of students demonstrated incorrect ideas about synaptic transmission. When targeting spatial and temporal summation, only eleven students (3.5%) were able to accurately depict at least one form of summation. In response to both drawing questions, student drawings revealed multiple alternative conceptions that resulted in a deeper analysis and characterization of the wide variation of student ideas.
Eat to Reproduce: The Role of Diet Quantity on Honey Bee (Apis Mellifera) Caste Determination
(North Dakota State University, 2017) Slater, Garett
The received wisdom is that diet quality drives this queen-worker dichotomy, even though diet quantity differs significantly between queen and worker diet. Diet quantity likely determines honey bee caste; yet it has never been explicated tested. In this paper, we tested the hypothesis of diet quantity induced caste determination by; first, determine the ubiquity of quantity induced caste systems among highly-related taxa; second, determining the relative contributions of diet quantity vs. diet quality on adult caste in honey bees; and third, determine the influence of diet quantity on important cellular and physiological pathways known during caste determination. I found that: 1) diet quantity determines caste in honey bees and other eusocial hymenoptera, and 2) honey bees do not have a critical weight. This research likely will move forward the field of honey bee caste determination, which is a model for high-order sociality and phenotypic plasticity.
The Effectiveness of 9, 10 Anthraquinone as a Repellent to Protect Oilseed Sunflower from Blackbird Depredation
(North Dakota State University, 2014) Niner, Megan Denise
Across the Prairie Pothole Region of North America, blackbirds (Icteridae) cause millions of dollars in damage to sunflower crops annually, but effective methods to prevent or limit blackbird damage to sunflower crops are lacking. I tested two repellents (Avipel and AV2022, both with active ingredient 9, 10 anthraquinone) under application conditions that would be appropriate for large-scale, sunflower farming in two consecutive years. In 2012, I conducted daily avian point counts and weekly crop damage surveys to assess blackbird use of, and damage to, plots of sunflowers were sprayed with Avipel or left unsprayed (i.e., control). In 2013, I placed six netted enclosures (each containing three male red-winged blackbirds, Agelaius phoeniceus, approximately 40 mature sunflowers and trays with cracked corn and water) in a plot of sunflower treated with AV2022 applied by a ground sprayer, and six netted enclosures (each containing three male red-winged blackbirds approximately 40 mature sunflowers and trays with cracked corn and water) in an adjacent plot of sunflower left untreated (i.e., control). Results from 2012 indicate that blackbird use of, and damage to, sunflower plots did not vary with treatment of Avipel. Results from 2013 indicate that enclosures in the AV2022 treated plot had sunflower plants with significantly more seed loss and significantly less cracked corn consumed from food trays than enclosures in the untreated (i.e., control) plot. I conclude that 9, 10 anthraquinone does not significantly reduce blackbird damage to sunflower crops when applied using typical methods for pesticides in large-scale, commercial agriculture.
Effects of nest site environment and timing of breeding on reproductive success in Franklin's gulls (Larus pipixcan)
(North Dakota State University, 2009) Berg, Emily Anne
Offspring performance and phenotype are affected by genotype and environment, which in birds includes yolk resources (part of the embryonic environment). Female colony nesting birds may influence offspring competitive ability in the post-hatching nest site environment by differentially allocating yolk resources to eggs based on nest site characteristics. Offspring performance may also be linked to prenatal allocation of resources, as well as post-natal parental care. Nest site characteristics, including nest size, density, and timing of breeding, influence the behavior (e.g., aggressive, social) and resource acquisition of the parents, as well as provide measureable variation in the postnatal environment. I used an experimental approach to quantify relationships among nest site characteristics, nest success, and offspring performance (growth and survival) in a nesting colony of Franklin's gull (Larus pipixcan). I also used a cross-foster experiment to examine tbe effects of parental care and provisioning on growth and survival of neonates. Timing of breeding, egg quality, chick quality, nest success and chick survival varied between the 2006 and 2007 cohorts. Nests in 2006 were initiated later than nests in 2007 and experienced lower nest survival rates but produced chicks in better condition. Chicks in 2006 also experienced higher survival than chicks in 2007; however, chicks in 2006 experienced slower growth. Timing of breeding may have influenced measures of nest and chick success examined in this study. In Franklin's gull, a trade-off between offspring quality and offspring quantity may be a consequence of migratory delays or unusual weather patterns in this long-distance migratory species.
Effects of Processing on Health-Promoting Attributes of Soymilk Phenolics
(North Dakota State University, 2010) Tan, Yingying
This study was designed to investigate the effects of different processing methods on the antioxidant and anti-cancer properties of soymilk crude phenolic extract (CPE) using the human prostate cancer cell line DU 145 as a model system. Four grinding methods and two ultra-high temperature (UHT) processing methods were investigated. Briefly, the four grinding methods included grinding with tap water (Method 1), okara-washed water (Method 2), soaked water (Method 3), as well as both okara-washed water and soaked water (Method 4); the two UHT processing conditions included one-phase UHT (143 °c, 60 s) and two-phase UHT (120 °C, 80 s + 140 °C, 4 s) methods. The antioxidant capability of CPE was measured by oxygen radical absorbance capacity (ORAC) and/or ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging activity (DPPH) assays. The DU 145 human prostate cancer cell line was sub-cultured in the presence of CPE at various concentrations (0, 1, 2, 4, 8 mg/ml) for 48 h and the percentage of cell viability was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and/or flow cytometric analysis with carboxyfluorescein succinimidyl ester (CFSE) staining. An induction of apoptosis was detected by flow cytometric analysis with annexin V/ propidium iodide (Pl) double staining, morphological change observation with acridine orange/ethidium bromide (AO/EB) double staining, and Western blot assay of apoptotic proteins. The results showed that grinding Method 4 and the two-phase UHT method exhibited greater total phenolic content and antioxidant capability than the other three grinding methods and one-phase UHT, respectively. In addition, soymilk CPE inhibited cell proliferation in a dose-dependent manner and upon purification. The anti-proliferation effects observed in soymilk CPE were associated with the apoptosis induction in DU 145 cell line as evidenced by morphological changes and the expression of apoptotic proteins. These results suggest that the soymilk CPE plays an important role in anti-proliferation, and apoptotic properties of soy in DU 145 cells. Furthermore, these health-promoting properties were affected by processing conditions, such as grinding and thermal conditions. The results of this study benefit the soy product industry to select appropriate processing conditions to retain more health-promotion phytochemicals during soy food's processing.
The Effects of Variation in Temperature and Parental Behavior on Offspring Body Mass, Telomeres and Survival Are Context-Dependent in Free Living House Sparrows (Passer domesticus)
(North Dakota State University, 2022) Dennis, Abigail
Although developing birds are vulnerable to extreme and erratic temperature conditions associated with climate change, parents have some ability to buffer these effects via incubation and postnatal behavior. However, parents are constrained by their own physiology and ecology. In this thesis, I sought to determine which factors (seasonal thermal profile, consistency of ambient temperature and/or parental behavior) drove traits linked to fitness across ontogeny in free-living house sparrow nestlings (Passer domesticus). I found that the effects of these factors were context-dependent; seasonal thermal profile and average temperature were important in shaping body size across ontogeny, but variance in nest temperature and female postnatal visits better predicted hatching and day 10 survival, respectively. Future studies should seek to answer these questions in other populations and explore hypotheses surrounding interactions between developmental environments to better our understanding of climate change and thermoregulation in response to increasingly warm and erratic global temperatures.
Emotion regulation moderates the prospective association between ERN and anxiety in early adolescence: An age-specific moderation of cognitive reappraisal but not expressive suppression
(North Dakota State University, 2024) Tan, Jaron Xe Yung
The increasing prevalence of anxiety problems during adolescence underscores the importance of a better understanding of the development of anxiety. While past research has highlighted a link between error responsivity, indexed by error-related negativity (ERN), and youth anxiety, the role of emotion regulation in the ERN-anxiety relationship remains unclear. We conducted a two-wave study with 115 healthy nine-12-year-olds, and found that expressive suppression (ES), an important emotion regulatory strategy, moderates the ERN-anxiety association. A larger T1 ERN predicted heightened T2 anxiety symptoms in those with higher ES. Interestingly, the moderating effect of cognitive reappraisal (CR), another important emotion regulatory strategy, on the ERN-anxiety association was age-dependent; in older youths, the association between T1 ERN and T2 symptoms was significant only for those with lower CR. These findings offer novel insights into the differential age-related patterns in the moderating effects of emotion regulation, and inform future emotion intervention studies for youths.
Energetics of Interrupted Development in Megachile rotundata
(North Dakota State University, 2022) Walter, Rikki
Insects in temperate regions may experience temperature fluctuations during springtime development which can lead to low temperature stress. Previous research has shown that short artificial fluctuations in temperature during interrupted development are advantageous when compared to static temperatures, but it is unclear why. One idea is it allows insects to repair chill injury and maintain cellular membrane potential. My goal was to understand what macromolecules are maintaining ion balance through measuring the respiratory quotient (RQ), trehalose, glycogen, simple sugars, and lipids using biochemical assays. The development of Megachile rotundata was stimulated for two weeks before interrupting with either fluctuating or static temperature regimes. RQ was measured repeatedly over two weeks and subsets of bees from each treatment were frozen at the same time points for biochemical analyses. The RQ varied over time and lipids and trehalose had the biggest differences between static and fluctuating temperatures as well as over time.
Environmental Components of Phenotypic Variation Dietary and Trans-Generational Effects on Behavior
(North Dakota State University, 2017) Garrison, Courtney
Phenotypic variation, or the total variation in a trait, and its components are of great importance in the fields of evolutionary and behavioral ecology. Phenotypic variation can be broken down into both environmental and genetic influences on that particular trait. However, due to an increasing trend of quantitative genetics in behavioral studies, researchers have begun to consider lesser studied components of phenotypic variation in addition to the commonly studied direct environmental and genetic influences. Some of these lesser studied components include maternal and paternal effects, or the effect that parental phenotype has on their offspring’s phenotype. In Chapter 1, I examine the impacts of direct environmental manipulation on cricket song production. For Chapter 2 however, instead of examining the direct environmental influence at the individual level, I examine, through meta-analysis, how the indirect environmental influences that occur at both the maternal and paternal level impact offspring phenotype across taxa.
Environmental Factors Influencing Tumor Associated Pericyte Phenotype in Pancreatic Cancer
(North Dakota State University, 2021) Delgado, Alexander
Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the U.S. with a 5-year survival rate of 11%. PDAC patients suffer from the lack of effective treatment options largely due to the limited delivery efficacy of the drugs. Tumor vessels are abnormal, leaky, and lack proper pericyte coverage, contributing to elevated hypoxia and interstitial fluid pressure, promoting cancer progression and metastasis, and inhibiting drug delivery efficacy. In the case of PDAC, a large portion of blood vessels were covered by α-smooth muscle actin (αSMA) expressing pericyte, which is normally absent in capillary pericytes. We also showed that PDAC cancer cell-derived exosomes could induce αSMA expression in the pericyte suggesting the pericyte phenotype is influenced by the Tumor Microenvironment (TME). Induced αSMA expression in pericyte disrupted the 3D tube formation efficiency when cultured with endothelial cells suggesting αSMAhigh pericyte confers a pathological feature of tumor blood vessels.
Environmental Impacts on Behavior and Personality in the Caviomorph Rodent, Octodon degus
(North Dakota State University, 2019) Johnson, Nicholas Edwin
Environmental factors can have large impacts in shaping the way that animals behave. Biotic elements, such as predators and conspecifics that individuals interact with, are two environmental factors that animals may encounter on a regular basis. Here, we present the results of two studies examining the relationship of these biotic factors to behavior and personality in the degu (Octodon degus), a social rodent species endemic to central Chile. We found that long-term experimental isolation from predators has not impacted behavior, as indicated by an open field test in this species. We also found that social groups in this species do not adhere to either conformity or social niche specialization expectations with regard to personality, as determined in open field tests. These results raise further questions as to the mechanisms that govern behavior, as well as how personality evolved and is maintained in natural populations.
Establishing and Characterizing Patient-Derived Breast Cancer Cell Lines
(North Dakota State University, 2022) Mohammadi, Farid Solaymani
Commercial cancer cell lines have long been extensively used as an important platform to study cancer. They have contributed to a plethora of discoveries in the field of cancer research. However, there are limitations with using these cell lines, such as induced mutations over the long-term in vitro culture. These mutations cause incorrect exhibition of the in vivo characteristics of the cancer cells. Here, we focused on establishing Patient-derived breast cancer cell lines and attempted to characterize them in terms of several biomarkers that are shown to be overexpressed in breast cancer cells. Patient-derived breast cancer cell lines are more reliable tools to study the molecular and cellular processes taking place in vivo, since they are freshly isolated from the tumor biopsy and do not undergo induced immortalization. We explored the CK19, Ki67, vimentin, EpCAM, E-cadherin, and N-cadherin expression in three successfully established patient-derived breast cancer cell lines.
Evaluation of Blackbird Damage to Sunflower and the Relationship to Producer Damage Estimates
(North Dakota State University, 2024) Donaldson, Morgan
Sunflower producers face profit losses due to crop depredation by migrating blackbirds (Icteridae). Blackbird damage to sunflower in North Dakota is highly localized, where economic loss to some sunflower fields is severe (loss >20%), others face negligible loss (<5%). To mitigate conflict between producers and blackbirds, an understanding of severity and distribution of bird damage is essential. We investigated blackbird damage to sunflower using estimates collected in the field and estimates gathered from producers through a written survey and direct contact. Damage estimates indicate a state-wide loss of US$10.3-33.5 million. Our comparison of estimates from 2020 indicate that blackbird damage is higher when reported by producers (i.e., survey and direct contact) when compared to infield estimates. The disparity of estimates and unpredictability of bird damage warrants investigation into estimation practices by both biologists (i.e., improved field and survey methods) and farmers (e.g., yield monitors) to achieve accurate estimates of damage.

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