Life Sciences Commons^™

Airborne Transmission Of Pathogens Emerging In The Poultry Industry, Xuan Dung Nguyen

Doctoral Dissertations

Poultry houses might have high levels of airborne pathogens, including Escherichia coli (E. coli) and avian influenza (AI), which may be transmitted through the air and pose risks of infection. The objective of the dissertation is to provide an insightful understanding the of airborne transmission of E. coli and AI which were attached to poultry dust particles.

Chapter I and VI summarized background, gap in knowledge, and discussed the limitations and implications of the study.

Chapter II compared the efficiency of Andersen six-stage impactor, all-glass impinger, and ACD-200 Bobcat, in collecting airborne E. coli carried by dust particles. The results …

Corn (Zea Mays L.) Production In Living Mulch Systems, Grazing Potential, And Economic Viability, Marcia Peireira Quinby

Doctoral Dissertations

Living mulch (LM) is a practice in which forages are grown simultaneously with the main crop, serving as a living cover throughout the growing season. The LM systems were developed to alleviate concerns of soil depletion and finding ways to reduce tillage negative effects on soil productivity. In addition, when legumes are use can decrease the reliance on N fertilizer. The use of corn in LM have been previously studied due to the crop being a large commodity in the U.S.; In addition, the ability to graze the LM after corn production can increase the land use efficiency. To determine …

Cerulean Warbler Full Annual Cycle Ecology: Filling In Critical Knowledge Gaps, Douglas W. Raybuck

Doctoral Dissertations

Cerulean Warblers (Setophaga cerulea) are a declining migratory bird species of conservation concern that breed in mature hardwood forests of eastern North America and spend the stationary non-breeding period in the tropical Andes of South America. To reverse their >50-year population decline, a full annual cycle conservation strategy is needed. However, several important knowledge gaps have limited our understanding of this species’ full annual cycle ecology, including migration ecology, response to forest management on the breeding grounds, and basic ecology during the stationary non-breeding period in Andean forests. From geolocator data, we found a moderate pattern of migratory …

Wc1 And Tcr Interactions For Γδ T Cell Activation, Alexandria Gillespie

Doctoral Dissertations

Major subpopulations of gamma delta T cells within ruminant and pigs are defined by expression of WC1, a hybrid pattern recognition receptor/co-receptor to the T cell receptor (TCR). It is known that when WC1 is knocked down cells fail to respond. Showing that WC1 plays an active role in the stimulation of bovine gamma delta T cells. Here we explored the spatio-temporal dynamics of WC1 and TCR interaction using imaging flow cytometry and stochastic optical reconstruction microscopy. We found that in quiescent gamma delta T cells both WC1 and TCR existed in separate protein domains (protein islands) but after activation …

Genomic Organization And Expression Of The Wc1 Hybrid Coreceptor And Pattern Recognition Receptor On Porcine Gamma Delta T Cells, Lauren Le Page

Doctoral Dissertations

gd T cells are a crucial component of the immune response to a number of increasingly relevant and largely zoonotic pathogens to which efficacious vaccination is lacking. In ruminants and swine, gd T cells represent a major population of peripheral blood and epithelial tissue-resident lymphocytes. gdT cells respond to both protein and non-protein antigens independently of MHC presentation and possess immunological memory. Upon activation, gamma delta T cells illicit a variety of effector functions and play an indispensable role of orchestrating the downstream immune response. These characteristics make gamma delta T cells a promising candidate for recruitment by vaccination, however, …

Drivers And Direct Impacts Of Lean Mass Dynamics On The Stopover Ecology And Migratory Pace Of Nearctic-Neotropical Migrant Songbirds In Spring, Mariamar Gutierrez Ramirez

Doctoral Dissertations

Annual migration in songbirds is one of the most demanding life-history stages. It represents a period of high mortality, yet there is still much unknown about the ecological correlates that influence its successful completion. After long non-stop migratory flights, birds require a stopover period to rest and replenish depleted energy reserves. Birds use fat as the primary fuel to power long-distance flights. However, birds also burn lean tissue, which results in significant reductions in muscle and organ masses. The discovery and quantification of lean mass catabolism represented a paradigm shift in migration ecology because non-fat components were thought to remain …

Thermal Ecophysiology Of Juvenile Anadromous River Herring, Lian W. Guo

Doctoral Dissertations

Temperature controls the rate of all biochemical processes, and thus can significantly influence the physiology and ecology of all living organisms on earth. Understanding how temperature influences fitness can therefore provide insight into mechanisms affecting population size, dynamics, and geographic distributions, especially in the context of climate change. Early life stages of fishes experience significant selective pressure to grow large and accumulate energy reserves in order to avoid predation and starvation. Increasing temperatures will increase routine metabolic rates, which may result in less energy being available for growth and energy storage. In this thesis, I examine the effects of temperature, …

Monitoring Mammals At Multiple Scales: Case Studies From Carnivore Communities, Kadambari Devarajan

Doctoral Dissertations

Carnivores are distributed widely and threatened by habitat loss, poaching, climate change, and disease. They are considered integral to ecosystem function through their direct and indirect interactions with species at different trophic levels. Given the importance of carnivores, it is of high conservation priority to understand the processes driving carnivore assemblages in different systems. It is thus essential to determine the abiotic and biotic drivers of carnivore community composition at different spatial scales and address the following questions: (i) What factors influence carnivore community composition and diversity? (ii) How do the factors influencing carnivore communities vary across spatial and temporal …

The Effects Of Urbanization On The Avian Gut Microbiome, Mae Berlow

Doctoral Dissertations

The gut microbiome influences and is influenced by the host, and can affect the host organism by contributing to health, development and immunity. Similarly, the host can influence this community; it’s makeup can vary with host species, locality, diet, social stressors, and environmental stressors. Some of these environmental stressors have arisen due to human-induced rapid environmental change, like urbanization. The physiology and behaviors of organisms that are able to persist in urban environments are often different from their non-urban congeners. Nutrition, development, and immunity—all of which are affected by the gut microbiome—are important factors that can determine survival in urban …

Microbial And Metabolomic Biomarkers Of Feed Efficiency In Angus Cattle, Brooke Ashley Clemmons

Doctoral Dissertations

In Tennessee and the United States, cattle account for a significant proportion of the livestock agricultural sector. In the beef cattle industry, 40-70% of the total cost of production comes from feed costs, resulting in billions of dollars going towards feeding cattle. Thus, identifying methods for improving feed efficiency is imperative for reduced feed input costs and more effective use of environmental and economic resources. The rumen microbiome contributes a vast amount of nutrients for the host ruminant, including approximately 70% of energy precursors as well as vitamins, proteins, and other nutrients. These microbes produce metabolites that are then available …

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren

Doctoral Dissertations

The motivation of my dissertation research was to understand the influence of climate and biotic factors on range limits with a focus on winter-adapted species, including the Canada lynx (Lynx canadensis), American marten (Martes americana), and snowshoe hare (Lepus americanus). I investigated range dynamics along the boreal-temperate ecotone of the northeastern US. Through an integrative literature review, I developed a theoretical framework building from existing thinking on range limits and ecological theory. I used this theory for my second chapter to evaluate direct and indirect causes of carnivore range limits in the northeastern US, …

Physiology Of A Basal Vertebrate, The Sea Lamprey (Petromyzon Marinus): Osmoregulation And Corticosteroid Action, Ciaran A. S. Shaughnessy

Doctoral Dissertations

Lamprey represent the most basal living example of a vertebrate animal which regulates its internal fluid and ion homeostasis. This phylogenetic position among vertebrates makes lamprey an important model organism for understanding the basal state, and thus the evolution, of physiological systems such as the mechanisms of osmo- and ionoregulation and the endocrine factors controlling them. Sea lamprey (Petromyzon marinus) are an anadromous fish, migrating from freshwater (FW) to seawater (SW) as juveniles, then returning back upstream as mature adults to spawn. Surviving this transition from a solute-poor FW environment to a solute-concentrated SW environment requires many changes …

Engineered Nanoparticles For Site-Specific Bioorthogonal Catalysis: Imaging And Therapy, Riddha Das

Doctoral Dissertations

Bioorthogonal catalysis offers a strategy for chemical transformations complementary to bioprocesses and has proven to be a powerful tool in biochemistry and medical sciences. Transition metal catalysts (TMCs) have emerged as a powerful tool to execute selective chemical transformations, however, lack of biocompatibility and stability limits their use in biological applications. Incorporation of TMCs into nanoparticle monolayers provides a versatile strategy for the generation of bioorthogonal nanocatalysts known as “nanozymes”. We have fabricated a family of nanozymes using gold nanoparticles (AuNPs) as scaffolds featuring diverse chemical functional groups for controlled localization of nanozymes in biological environments, providing unique strategies for …

Tpr-Containing Proteins Control Protein Organization And Homeostasis For The Endoplasmic Reticulum, Jill Bradley-Graham

Doctoral Dissertations

The endoplasmic reticulum (ER) is a complex, multifunctional organelle comprised of a continuous membrane and lumen that is organized into several functional regions. It plays various roles including protein translocation, folding, quality control, secretion, calcium signaling, and lipid biogenesis. Cellular protein homeostasis is maintained by a complicated chaperone network, and the largest functional family within this network consists of proteins containing tetratricopeptide repeats (TPRs). TPRs are well-studied structural motifs that mediate intermolecular protein-protein interactions, supporting interactions with a wide range of ligands or substrates. Nine TPR-containing proteins have been shown to localize to the ER and control protein organization and …

Temporal And Spatial Management Tools For Marine Ecosystems: Case Studies From Northern Brazil And Northeastern United States, Beatriz Dos Santos Dias

Doctoral Dissertations

Anthropogenic interventions and actions upon the marine habitat pose threats to a range of species of economic and conservation concern. The dynamic nature of marine ecosystems offers a difficult challenge to incorporate spatial and temporal distributions of different species, and the interactions among species and human activities into a formal management framework. Each country has its own priorities when it comes to management of the marine resources (e.g. conservation, food security, sustainable fisheries, and optimization of revenue). Therefore, a key hurdle is to create tools adequate for use within an Ecosystem Approach to Management (EAM) and Ecosystem-based Management (EBM) framework, …

Population Viability And Connectivity Of The Federally Threatened Eastern Indigo Snake In Central Peninsular Florida, Javan Bauder

Doctoral Dissertations

Understanding the factors influencing the likelihood of persistence of real-world populations requires both an accurate understanding of the traits and behaviors of individuals within those populations (e.g., movement, habitat selection, survival, fecundity, dispersal) but also an understanding of how those traits and behaviors are influenced by landscape features. The federally threatened eastern indigo snake (EIS, Drymarchon couperi) has declined throughout its range primarily due to anthropogenically-induced habitat loss and fragmentation making spatially-explicit assessments of population viability and connectivity essential for understanding its current status and directing future conservation efforts. The primary goal of my dissertation was to understand how …

Not Gone With The Wind: Addressing Effects Of Offshore Wind Development On Bat Species In The Northeastern United States, Zara Rae Dowling

Doctoral Dissertations

Development of coastal and offshore wind energy resources has the potential to add considerable renewable electricity capacity to the United States electrical grid, but could have detrimental impacts on wildlife. Land-based wind energy facilities are estimated to kill hundreds of thousands of bats every year in the United States, and could threaten population viability of some species. Little is known about the potential impacts of offshore wind development on bat populations along the North Atlantic coast, but a number of species are known to frequent marine islands or fly over the ocean during migration. This dissertation helps to characterize risks …

The Role Of Phenotypic Integration In Mammalian Tooth Function And Jaw Morphological Diversity, Andrew Conith

Doctoral Dissertations

Here I investigate how two major components of the mammalian feeding system, teeth and jaws, are influenced by functional, environment, and developmental factors. First, I build physical models of the molars from two early mammals, Morganucodon and Kuehneotherium, and compare their ability to process a proxy food item. Early mammals were under strong selection to reduce metabolic costs, so any savings in energy during feeding would be advantageous. I tested the ability of both mammals to process a hard and soft food item with material properties similar to that of the insects they would have likely consumed. Morganucodon was …

Calcium And Metabolism In Sperm: Fundamental Players For Fertilization And Embryo Development, Felipe Navarrete

Doctoral Dissertations

Mammalian sperm acquire the fertilizing ability in the female tract in a process known as capacitation. At the molecular level, capacitation is associated with the up-regulation of a cAMP-dependent pathway, changes in intracellular pH, intracellular Ca²⁺, ATP consumption and an increase in tyrosine phosphorylation. However, little is known about the function of Ca²⁺ and ATP during this important process. These signaling systems interact during capacitation are still not well understood. Results presented in this study indicate that Ca²⁺ ions have a biphasic role in the regulation of cAMP-dependent signaling. Sperm incubated in zero Ca²⁺ in …

Burrowing And Walking Mechanisms Of North American Moles, Yi-Fen Lin

Doctoral Dissertations

Moles (Family Talpidae) are a classic example of extreme specialization, in their case highly derived forelimb morphologies associated with burrowing. Despite many observations of mole burrows and behaviors gathered in the field, we know very little about how and how well moles use their forelimbs to dig tunnels and to walk within the built tunnels to collect and transport food. The first chapter investigates the effect of soil compactness on two sympatric mole species under controlled laboratory conditions. My results demonstrate that increasing soil compactness impedes tunneling performance as evidenced by reduced burrowing speed, increased soil transport, shorter tunnels, shorter …

Identifying Genome Associations With Unique Mastitis Phenotypes In Response To Intramammary Streptococcus Uberis Challenge, Lydia Jean Siebert

Doctoral Dissertations

Mastitis, the inflammation of the mammary gland, dramatically decreases dairy industry revenues and milk quality, making improved control and prevention methods a goal of the industry. Prior research has observed variation in response to experimental challenge with regards to inflammation indicators, S. uberis concentrations, and the need for antibiotics. To determine possible causes of the observed variation following experimental S. uberis intramammary challenge, we performed genome association analyses (N = 34 – 36 Holstein dairy cows), a linkage analysis, and S. uberis milk inoculation (N = 21 Holstein dairy cows) trials. Association analyses were done using Illumina’s BovineSNP50 BeadChip and …

Alternative Approaches To Improving The Welfare Of Transition Dairy Cows And Their Calves: Use Of Exercise, Randi Alyson Black

Doctoral Dissertations

Transition cows are the cows most susceptible to disease and prevalence has not changed over the past decade. However, increased physical activity during late gestation may represent a management option to improve transition. Therefore, the objectives of this study were to determine the effect of exercise, pasture turnout, or total confinement on 1.) physical fitness and cortisol concentrations during the dry period, 2.) neutrophil function and behavior during the dry period, 3.) horn growth and wear and sole thickness during the dry period 4.) calving behavior and cortisol concentrations at parturition, and 5.) calf performance, behavior, and cortisol concentrations at …

Distribution And Population Dynamics Of Ungulates In The Mongolian Gobi, Buuveibaatar Bayarbaatar

Doctoral Dissertations

The Mongolian Gobi is one of the most spectacular and important regions in Central Asia, comprising the largest area of intact grassland in the world. In recent years, a growing human population, expanding exploitation of natural resources, and the development of infrastructure in the region place increasing pressure on these species and their habitats. This dissertation has focused on three species of ungulates such as Mongolian saiga (Saiga tatarica mongolica) in western Mongolia, and Asiatic wild ass (Equus hemionus), and goitered gazelle (Gazella subgutturosa) in Southern Gobi. The study on endangered saiga antelope in …

Regional Recruitment Dynamics And Seasonal Ecology Of Juvenile Bluefish (Pomatomus Saltatrix), David G. Stormer

Doctoral Dissertations

Recruitment in fishes, defined as the survival of a cohort through the first year of life, can be highly variable and affected by small changes in biological and physical factors. Much of the historical focus into the sources of recruitment variability has concentrated on the larval stage, but recent attention has shifted to the relatively longer juvenile period. Spawning behavior that results in the production of multiple cohorts over time and space within a year-class may dampen recruitment variability by decreasing natural mortality risk. The bluefish (Pomatomus saltatrix) is a migratory marine species that produces multiple cohorts of …

Health Assessment Of Two Reintroduced Populations Of American Martens (Martes Americana) In Michigan, Maria Catherine Spriggs

Doctoral Dissertations

The American marten (Martes americana) was extirpated from Michigan during the early-20th century due to loss of vast areas of mature conifer forest and unregulated trapping. The species was reintroduced into the Upper Peninsula (UP) and Northern Lower Peninsula (NLP) during the mid-20th century. While the American marten population in the UP has grown and is doing well, the population in the NLP has been less successful. The reasons for the limited success of the NLP population are unknown, but may include lack of suitable habitat, limited reproductive success, poor genetic diversity, disease, or negative environmental impacts. American …

Evaluation Of Reproductive Efficiency In Lactating Dairy Cows Through Physiologic Evaluation And Synchronization Modification, Charles Dexter Young

Doctoral Dissertations

Reproductive performance of lactating dairy cows has decreased as milk production has increased as a result of genetic selection. Milk production alone is not the reason for decreased reproductive performance, as fertility issues are multifactorial and collaborative. Research chapters contained within have taken an applied approach focusing in two different areas of fertility. One approach was development of an evaluation system to identify lactating cows with decreased fertility prior to breeding; while another approach was to modify an ovulation synchronization protocol during periods of heat stress in order to improve fertility. The first focus was development and evaluation of a …

Thermal Inactivation Of Shiga Toxin-Producing Escherichia Coli In Foods, Malcond David Valladares

Doctoral Dissertations

Emerging non-O157 Shiga toxin-producing Escherichia coli (STEC) were recently added to the zero tolerance policy by the USDA-FSIS. Therefore, the precise characterization of their thermal inactivation kinetics in different foods and the effect of stress on thermal inactivation are needed. This research aimed at determining the heat inactivation kinetics of non-O157 and O157 STECs in buffer and model food matrices and the effects of DnaK levels on thermal resistance after acid and heat-shock. Thermal inactivation was carried out in either in 2-ml glass vials or nylon vacuum-sealed bags for buffer and food (spinach, ground-beef, turkey deli-meat, pasta) samples, respectively. Vials …

A Novel Population Of Natural Killer Cells Plays A Critical Role In The Depletion Of Splenic B2 B Cells During Experimental African Trypanosomiasis, Deborah Frenkel

Doctoral Dissertations

Loss of humoral immune competence in T. brucei-infected mice is associated with the apoptotic depletion of splenic transitional, marginal zone and follicular B cells as well as a depletion of CD8⁺ T cells. This occurs rapidly after infection and impairs responses to vaccine antigens in addition to responses to newly arising VSG antigenic variants, leading to uncontrolled parasite growth and death of the infected mice. Infection-induced B2 B cell and CD8⁺ T cell loss requires the presence of a novel population of natural killer (NK) cells and is mediated by a perforin-dependent process consistent with perforin- and …

Absorption And Utilization Of Choline And Vitamin B12 In Lactating Dairy Cows Using Different Delivery Methods, Virginia Maria Artegoitia Etcheverry

Doctoral Dissertations

Choline and vitamin B12 are essential nutrients for growth and performances of production animals. However, both nutrients are extensively degraded during digestion in the rumen. This thesis comprised three experiments. First, four cows equipped with a rumen cannula and catheters in the portal vein and a mesenteric artery received a post-ruminal bolus of: 1) cyanocobalamin (CN-CBL) alone (0.1 g) [gram], 2) CN-CBL (0.1 g) + casein (10 g) or 3) CN-CBL (0.1 g) + whey proteins (10 g). After the bolus, blood samples were taken until 24 h [hour] post-bolus. The intestinal absorption of CN-CBL was greater when the vitamin …

Casein Micelles And Their Properties: Polydispersity, Association With Vitamin A And Effect Of Ultra-High Pressure Homogenization, Maneesha Sheenu Mohan

Doctoral Dissertations

The internal structure of casein micelles is not fully understood. In the present work, we explore some of the basic questions about casein micelles in bovine milk including its size distribution, native binding properties and effect of ultra-high pressure homogenization (ultra-HPH) on technological properties of casein micelles. The size distribution of casein micelles was studied by cryo-TEM using skim milk from four cows. The degree of variation in casein micelle sizes (polydispersity) ranged between 0.39 and 0.47 for a size distribution ranging from 10 to 693 nm. These results indicated high polydispersity of casein micelles in milk from single cows. …