The CCAAT/enhancer-binding protein delta (C/EBPδ) is a highly conserved transcription factor capable of regulating numerous cell fate processes, such as cell growth, differentiation, proliferation and apoptosis. C/EBPδ is inducible during cellular stress responses, including inflammation and responses to growth factor deprivation or thermal stress. C/EBPδ is stress-inducible in a diversity of fishes, including the zebrafish Danio rerio; however, little is known about its role in fish development. Here I show that overexpression of C/EBPδ leads to severe developmental defects, including reduced body length, edema, liver malformation and retinal abnormalities. The proportion of individuals that display developmental abnormalities is significantly greater in C/EBPδ-overexpressing embryos compared to control embryos and overexpression significantly reduces survival of larvae over time. TUNEL analysis suggests C/EBPδ-overexpressing embryos exhibit a pattern of apoptotic cell death which is spatially distinct from control embryos. These data support a critical role for C/EBPδ in numerous developmental processes, including promoting programmed cell death during development. Mutations in C/EBPδ have been implicated in the progression of human tumors, including those of myeloid, hepatocellular and breast cancers. Therefore, the C/EBPδ-overexpressing zebrafish will serve as a valuable model for examining the role of this gene during development, as a part of the cellular response to stress and in pathological states such as tumor progression.

Very few vertebrates survive extended periods of time without oxygen. Entry into metabolic depression is central to surviving anoxia, which is supported by overall suppression of protein synthesis, yet requires increased expression of specific proteins. Studying the rapid and complex regulation of gene expression associated with survival of anoxia may uncover new mechanisms of cellular biology and transform our understanding of cells, as well as inform prevention and treatment of heart attack and stroke in humans. Small non-coding RNAs (sncRNAs) have emerged as regulators of gene expression that can be rapidly employed, can target individual genes or suites of genes, and are highly conserved across species. There are diverse types of sncRNAs, some coopted from degradation of longer RNAs in the cell. The sncRNA revolution has yielded a large body of literature revealing the roles of sncRNAs in a myriad of biological processes, from development to regulation of the cell cycle and apoptosis, to responding to stress, including freezing, dehydration, ischemia, and anoxia. Given the regulatory complexity required to survive anoxia, examining sncRNAs in the context of extreme anoxia tolerance has the potential to expand our understanding of the role that sncRNAs may play in basic cell biology, as well as in response to stresses such as anoxia. A comparative model including anoxia-tolerant and anoxia-sensitive phenotypes allows us to better identify sncRNAs that likely play a critical role in anoxia tolerance. Embryos of A. limnaeus are the most anoxia tolerant vertebrate known and are comprised of a range of anoxia-tolerance phenotypes. These characteristics create a unique opportunity for comparative study of the role of sncRNAs in anoxia tolerance in phenotypes with a common genomic background. The overall goals of this project were to: (1) describe the sncRNA transcriptome and changes in its expression in response to anoxia in the embryos of A. limnaeus and in other anoxia-tolerant vertebrates, and (2) to identify specific sncRNAs of interest based on these sequencing projects and to follow-up on their biogenesis, localization, and function in A. limnaeus embryos and a continuous cell line derived from A. limnaeus embryos. Chapter 2 focuses on the identity and expression of sncRNAs in embryos of A. limnaeus in 4 embryonic stages that differ in their anoxia tolerance and physiology. Chapter 3 explores sncRNA expression in brain tissue (the most oxygen-sensitive organ) in other anoxia-tolerant vertebrates: the crucian carp, western painted turtle, leopard frog, and epaulette shark. This allows us to assess the similarities and differences in sncRNA biology in species that evolved anoxia independently, and put the findings from A. limnaeus in an evolutionary context. Chapter 4 describes the establishment of the AL4 anoxia-tolerant cell line derived from A. limnaeus embryos, which allows for more detailed study of particular sncRNAs of interest in Chapter 5. Using whole embryos of A. limnaeus and the AL4 cell line, Chapter 5 describes the expression, localization, and possible biogenesis and mechanism of action of mitochondria-derived sncRNAs, known as mitosRNAs. Chapter 6 summarizes the findings and discusses potential future directions. The work in this dissertation represents the first global survey of sncRNA expression in anoxia tolerant vertebrates. While many interesting patterns of expression were identified, the most interesting discovery is the expression of sncRNAs that are generated in the mitochondria, but have the potential to function in other compartments of the cell. This discovery could transform the way we view the role of the mitochondria in regulating gene expression in eukaryotic cells.

Coral reefs on Florida’s Reef Tract (FRT) are susceptible to many anthropogenic influences including controlled freshwater discharges and agricultural runoff as well as high natural environmental variability from seasonal rainfall, runoff and upwelling. To better understand coral population structure and responses to sublethal stressors, populations of the scleractinian coral Montastraea cavernosa in the northern FRT were examined using a combination of genomic and transcriptomic techniques. Microsatellite genetic markers identified high local retention among sites and a slight southward gene flow. An in-situ temporal gene expression analysis utilizing a tag-based sequencing transcriptomic approach was used to analyze baseline coral health at St. Lucie Reef (SLR), off Stuart, FL. Temporal variation had the greatest influence of differential gene expression among M. cavernosa at SLR. Results will be shared with local resource managers and coupled with a complementary ex-situ experimental trial. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

No description available.

No description available.

Bibliography: leaves 187-216.

The intertidal red algal genus Porphyra is found on rocky shores worldwide. In the Northern Hemisphere the genus is well studied but there is a paucity of data on southern hemisphere Porphyra and even less on New Zealand Porphyra. The species� taxonomy has been undergoing revision since the late 1990�s, when it was discovered that the main species P. columbina and P. lilliputana reported for New Zealand were a combination of several endemic species. These species are found from the low to the high intertidal watermark; hence they are exposed to fluctuating stresses such as desiccation, temperature, high light and UV radiation. Algae have evolved a number of mechanisms to adapt to naturally changing increasing abiotic conditions, such as accumulation of screening pigments and changes in antioxidant metabolism during light stress. For terrestrial plants, polyamines (small aliphatic amines) have been shown to be involved in protecting cells from damage under conditions of stress including UV-B radiation; such mechanisms have yet to be identified in algae. The overall aim of this study was to determine the importance of cellular processes in shaping the community structure of Porphyra on a wave-exposed shore on the east coast of the South Island, New Zealand. Porphyra distribution and community structure was assessed by regular monthly monitoring of presence and absence of Porphyra along four transect lines at the site. Enviromnental information was recorded to determine the effects of temperature, light, UV radiation, humidity and wind on Porphyra�s spatial and temporal distribution. Regular tissue samples were taken for species identification by the application of primers, which were specifically designed during this study. P. cinnamomea and Porphyra spec. "ROS 54" were identified as dominant species present almost throughout the year with a pronounced maximum in presence during late winter and spring, and some weeks of absence during April or May. The two dominant species were recorded from the low to the high intertidal shore, but the mid intertidal was identified as the preferred habitat. Other species that were found were rare and only present for a few months in a very restricted area. It was hypothesised that free radical generation and antioxidant metabolism are associated with desiccation tolerance in Porphyra. An attempt was made to investigate the impact of desiccation stress on Porphyra. The extraction process of antioxidants was problematic and no reproducible results could be obtained. It was attempted to investigate the spatial distribution of spores and conchocelis of different Porphyra species in the field, and determine if those found at Brighton Beach are species-specific in their morphology. This indicated that the two main Porphyra species at Brighton Beach not only prefer to occupy the same habitat but that they also have a morphologically similar conchocelis phase. Mechanisms on a cellular level such as polyamine metabolism affected by environmental (abiotic) stresses are related to the alga�s ability to adapt to stress and therefore can have an effect on Porphyra�s distribution along the shore and its presence throughout the year. The depletion of the ozone layer has become an important issue as the effects of increased UV radiation on the environment, especially the intertidal habitat, are revealed. Marine macrophytes possess the main three. polyamines: putrescine, spermidine and spermine of varying levels. For the few species studied, Rhodophyta generally contain higher levels of polyamines than Chlorophyta, while polyamine levels for the one heterokontophyte analysed were between Chlorophyta and Rhodophyta. Levels of the three most common polyamines (putrescine, spermidine, spermine) were determined in P. cinnamomea under controlled UV exposure. Tissue discs were exposed to visible light (PAR), PAR and UV-A or PAR, UV-A and UV-B radiation. Discs exposed to PAR and PAR and UV-A showed little change in polyamine levels over a six day trial period, while discs exposed to PAR, UV-A and UV-B showed a significant increase in free, bound soluble and bound insoluble polyamines over the same period of time. Correspondingly levels of ADC and ODC, two enzymes involved in polyamine synthesis, were measured. ODC levels changed little while ADC levels increased significantly during UV-B treatment, indicating that under UV-B stress polyamines are mainly synthesized via the ADC pathway. The experimental set-up and process of this study has not been applied in macroalgal polyamine research and results obtained are the first indication that increased levels of polyamines are involved in protection and/or protection mechanisms in macrophytic algae to prevent UV-B damage.

Bibliography: leaves 98-123. This thesis investigates the symptoms of leaf senescence in response to plant shoot water stress and demonstrates the effect of a non-hydraulic root signal in the senescence response of mature leaves of sunflower. The alleviation of the leaf soluble protein loss rate by excision of the root system in drying soil indicates that this signal originates in roots in dry soil and acts to promote protein loss.

This thesis focuses upon whether stressful aspects of an organism's environment are reflected by that organism's shape. It presents an application of the powerful thin-plate spline and relative warp methods from morphometric analysis to demonstrate the overall utility of morphometrics in detecting environmental stress in an estuarine flatfish, the English sole or Pleuronectes vetulus. Juvenile English sole were captured from the Yaquina Bay, Oregon, photographed using a digital camera, and then held without food in the laboratory for periods of 7 to 24 days. Landmarks on the outline of the ventral surface of the body were digitized from the images. The mean position of the landmarks for freshly caught sole was used to compute a reference specimen. The thin-plate spline method was then applied to quantify the intraindividual shape variation due to lab-induced environmental stressors for all fish. Relative warp analysis of the resulting landmark data yielded relative warp scores for each individual fish, and was analogous to a principal component analysis. Analysis of covariance of the relative warp (principal component) scores showed that fish held without food acquire different shape characteristics in comparison with freshly caught fish, and that these shape differences reflect captivity and food deprivation effects. A discriminant function analysis using the data allows clear differentiation of stressed and non-stressed fish. The underlying goal of this research was to examine the conceptual and methodological aspects of morphometrics relevant to its future potential use as a measure of developmental precision and environmental condition. The technique may have applicability for detecting environmental stress in natural populations of estuarine fish. / Graduation date: 2003

Stress, including extreme or rapidly changing temperatures, are known to have deleterious effects on fish health and physiology. This thesis examines the combined effects of elevated acclimation temperature and acute handling stress on the number of antibody producing cells, plasma lysozyme concentrations, and the number of pronephric leukocytes in juvenile chinook salmon (Oncorhynchus tshawytscha). An additional goal of this thesis was to explore the effects of a temperature fluctuation, as a potential instigator of thermal shock, on innate immunity in wild fall chinook salmon of the Columbia River, specifically to determine if there are effects on plasma lysozyme concentrations and on the frequencies of lymphocytes, neutrophils, and thrombocytes in circulation. Finally, based on results found in an experiment involving elevated acclimation temperature, the relationship between the number of antibody producing cells and fish body weight was examined. Plasma lysozyme concentrations and the number of pronephric leukocytes were both affected by acclimation to 21��C compared to 13��C. While a positive relationship was found between temperature and lysozyme, an inverse relationship was found between temperature and the number of pronephric leukocytes. Plasma lysozyme concentrations, the number of pronephric leukocytes, and the number of antibody producing cells did not respond to the stressor, and the combination of elevated temperature and stress did not have an additive effect on any of the physiological or immunological variables studied. Differences between controls and temperature-treated fish were not detected among individual time points throughout a temperature fluctuation experiment, despite overall responses in plasma lysozyme concentrations and the frequencies of circulating lymphocytes. The frequencies of circulating neutrophils and thrombocytes did not respond to the thermal stressor. Finally, a significant positive relationship was detected between the number of antibody producing cells (assessed by a hemolytic plaque assay) and body weight among non-stressed fish acclimated to 21��C and 13��C. Regardless of acclimation temperature, these results emphasize the importance of the standardization of fish size for immunological experiments. Results from this thesis suggest that some components of innate immunity are affected by elevated acclimation temperatures and that the adaptive immune system is affected by acclimation temperature differently in small and large fish. / Graduation date: 2001