Life Sciences Commons^™

Florida's Pillar Coral (Dendrogyra Cylindrus): The Roles Of The Holobiont Partners In Bleaching, Recovery, And Disease Processes, Cynthia Fairbank Lewis

FIU Electronic Theses and Dissertations

The iconic pillar coral, Dendrogyra cylindrus, is one of five Caribbean species listed in 2014 under the US Federal Endangered Species Act because of its extreme low abundance and continued decline in US waters. Until recently, little was known about the demographics or genetic diversity of Florida’s D. cylindrus population. This study represents the first time two holobiont partners (coral animal and associated photosynthetic algal endosymbionts) have been closely examined, spatially and temporally, in this little-studied species. The aim was to explore the influences of coral animal genotypes, mutualistic photosynthetic algal strains, and hyperthermal stress on bleaching and …

The Effects Of Copper Exposure On Fish Locomotion And Predator-Prey Interactions, Tiffany N. Yanez

FIU Electronic Theses and Dissertations

This study determined the effects of the copper water quality criterion (WQC) by the EPA on [1] swimming performance and [2] predator-prey interactions of the Sailfin Molly, across a salinity gradient. Fish acclimated to FW (0 ppt) and 8-ppt saltwater were exposed to 11.3 and 8.44 µg/L Cu for 96 h, respectively. At the end of the exposures, fish swimming performance was determined by using the critical swimming speed, U_crit, the speed at which a fish cannot longer maintain position in the water column. U_critwas then measured again after a 4-week depuration period to determine if …

A Mobile-Based Intervention For Obesity Prevention Among Female College Students In Saudi Arabia: A Randomized Controlled Trial, Abeer Hussain Alssafi

FIU Electronic Theses and Dissertations

College students transitioning from adolescence into early adulthood may encounter new stresses, which may lead to unhealthy weight-related behaviors and weight gain. Students gain approximately 4-9 pounds during their first 2 years in college. Health behaviors in this population pose an increased risk because they tend to persist into adulthood. In Middle Eastern countries including Saudi Arabia, student obesity is on the rise. About 24% of female college students were overweight or obese in Saudi Arabia in 2015. This dissertation describes the development of a mobile intervention program using Instagram and a self-tracking app to minimize the risk of overweight/obesity …

Superoxide Dismutase C Modulates Macropinocytosis And Phagocytosis In Dictyostelium Discoideum, Cong Gu

FIU Electronic Theses and Dissertations

Macropinocytosis and phagocytosis, two actin-dependent and clathrin independent events of endocytosis, enable the cells such as macrophages and neutrophils to either internalize pathogens and initiates the human innate immune response or serve as a direct entry route for productive infection of pathogen. Dictyostelium discoideum, soil-living amoeba, a unicellular eukaryote that could professionally internalize fluid phase or particles several folds more than that of macrophages and neutrophils. Additionally, multiple key signaling pathways are conserved between Dictyostelium and mammalian cells, including pathways affecting small GTPases Ras and Rac and their downstream effectors, and F-Actin remodeling. All these traits makes Dictyostelium an …

Hiv Tat And Morphine-Induced Neurodegeneration In A Beclin 1 Hemizygous Mouse Model, Jessica A. Lapierre

FIU Electronic Theses and Dissertations

Early in infection, HIV crosses the blood-brain barrier and induces neuropathology. Viral presence in the CNS coupled with secretion of neurotoxic proteins causes neuroinflammation, glial dysfunction, excitotoxicity, and neuronal death. Despite advances in combined antiretroviral therapy, HIV-infected patients present with a spectrum of cognitive and psychomotor deficits collectively referred to as HIV-associated neurological disorders (HAND). A subset of HAND patients abuses drugs such as opiates like heroin and morphine show an exacerbation and rapid progression of HIV neuropathology; however, the mechanisms of this synergy are not well understood. Autophagy is a lysosomal degradative process which eliminates and recycles cytosolic components …

Exploring The Neural Mechanisms Of Physics Learning, Jessica E. Bartley

FIU Electronic Theses and Dissertations

This dissertation presents a series of neuroimaging investigations and achievements that strive to deepen and broaden our understanding of human problem solving and physics learning. Neuroscience conceives of dynamic relationships between behavior, experience, and brain structure and function, but how neural changes enable human learning across classroom instruction remains an open question. At the same time, physics is a challenging area of study in which introductory students regularly struggle to achieve success across university instruction. Research and initiatives in neuroeducation promise a new understanding into the interactions between biology and education, including the neural mechanisms of learning and development. These …

Aptamer-Based Assay For Detection Of Ochratoxin A, Amanda Nicole Bartley

FIU Electronic Theses and Dissertations

Ochratoxin A (OTA) is a potent mycotoxin found in a wide range of agricultural products that has been linked to mitochondrial damage and renal disease. The standard methods for OTA analysis currently rely on the use of high-performance liquid chromatography (HPLC) coupled to fluorescence detection or mass spectrometry. Toward a highthroughput analysis of OTA, a single-stranded DNA aptamer, modified with a fluorophore, coupled to a complementary sequence, modified with a FRET-based quencher that dissociates in the presence of the target toxin, is proposed. In order to integrate “target trapping,” aptamer immobilization methods were explored to mediate interference issues. Assays were …

Epigenetic Mechanisms Regulating The Functional Effects Of Chronic Alcohol Exposure Of Human Monocyte-Derived Dendritic Cells, Tiyash Parira

FIU Electronic Theses and Dissertations

The effects of alcohol abuse are multi-dimensional since alcohol is widely known to affect both the innate and adaptive immune systems. Recently, epigenetics has come into focus and has been implicated in many diseases as well as substance abuse disorders. Therefore, research efforts of understanding the epigenetic mechanisms underlying substance abuse effects including alcohol abuse have become more predominant.

In our laboratory, we have studied different epigenetic changes induced by alcohol exposure including regulation of histone deacetylases (HDACs), histone quantity, and histone modifications such as acetylation and deacetylation. We have observed differential effects of acute and chronic alcohol exposure in …

Investigating The Role Of The Proximal Cysteine Hydrogen Bonding Network And Distal Pocket In Chloroperoxidase, Elwood Kwong Lam

FIU Electronic Theses and Dissertations

Chloroperoxidase (CPO) is one of the most versatile heme enzyme isolated from the marine fungus, Caldariomyces fumago. Functionally, CPO can catalyze four types of reactions: peroxidation (peroxidase-like), dismutation (catalase-like), halogenation (halogenase-like), and peroxygenation (P450-like). Structurally, CPO has a distal and proximal pockets that can be best described as a hybrid of classical peroxidase and P450s. As a heme-thiolate protein, CPO contains the conserved proximal Pro28-Cys29-Pro30 stretch found in other members of the family. However, the structural and functional roles of these proline residues remain poorly understood. Site-directed mutagenesis was undertaken to generates three CPO mutants, P28A-, P30A-, P28A/P30A-CPO. The replacement …

Folding Analysis Of Reduced Bovine Pancreatic Trypsin Inhibitor (Bpti) With Aromatic Thiols And Disulfides In Vitro, Na Zhang

FIU Electronic Theses and Dissertations

Almost all therapeutic proteins contain disulfide bonds to stabilize their native structure. Recombinant DNA technology enables many therapeutic proteins to be produced in bacteria, but the expression of native proteins is not always efficient due to the limited ability of bacteria to form disulfide bonds in vivo. It is often necessary to employ in vitro oxidative folding process to form the native disulfide bonds to obtain the native structure of disulfide-containing proteins. Aromatic disulfides are small molecules designed to match some of the physical properties of the active site of protein disulfide isomerase (PDI), which catalyzes the folding process of …

Mycobacterium Tuberculosis Inhibitors: Action And Resistance, Pamela K. Garcia-Moreno

FIU Electronic Theses and Dissertations

Tuberculosis, an infectious disease caused by Mycobacterium tuberculosis, has been a global health problem for years. The emergence of drug resistance in this organism generates the necessity of exploring novel targets and developing new drugs. Topoisomerases are enzymes found in all kingdoms of life responsible for overcoming the topological barriers encountered during essential cellular processes. The genomes of mycobacteria encode only one type IA topoisomerase (MtopI), which has been validated as a novel TB drug target. The goal of this study is to obtain new information on the mechanism and resistance of endogenous and synthetic inhibitors of MtopI.

Rv1495 is …

Factors Affecting Green Turtle Foraging Ecology Across Multiple Spatial Scales, Elizabeth Rose Whitman

FIU Electronic Theses and Dissertations

The hierarchical levels at which resource selection occurs can have important consequences for individual and population energy budgets and structure the impacts of a forager on its ecosystem. Assessing factors affecting resource selection of large marine herbivores across scales is important because of their potentially large impacts on seagrass community dynamics and historical and current changes in their population sizes and those of their potential predators. I explored the factors (predation risk, resource abundance, quality and identity) affecting resource use of large marine herbivores (green turtles, Chelonia mydas) from the scale of habitat patches to forage species within patches. …

Survival At The Summits: Amphibian Responses To Thermal Extremes, Disease, And Rapid Climate Change In The High Tropical Andes, Kelsey E. Reider

FIU Electronic Theses and Dissertations

Understanding biological responses to climate change is a primary concern in conservation biology. Of the ecosystems being rapidly impacted by climate change, those in the high-elevation tropics are among the most poorly studied. The tropical Andean biosphere includes record elevations above 5000 meters, where extreme environmental conditions challenge many organisms. In the Cordillera Vilcanota of southern Peru, frogs including Pleurodema marmoratum and Telmatobius marmoratus have expanded their ranges to 5244 – 5400 m into habitats created by glacial recession, making them among the highest recorded amphibians on Earth. To understand how hydrologic alterations from loss of glacial meltwater and climatic …

Sensitivity Of Marine Cynobacteria And Green Microlage To Nano And Bulk Zinc Oxides, Jennifer Gil-Acevedo 3664585

FIU Electronic Theses and Dissertations

Nanoparticles are particles with sizes between 1 and 100 nanometers (nm). Owing to their unique chemical, electrical, mechanical, optical, and piezoelectric properties, zinc oxide nanoparticles (ZnO-NPs) are finding widespread use in numerous applications with yearly production over 550 tons per year. Increasing use of ZnO NPs, and NPs in wastewater discharges from domestic and industrial sources will have significant potential for adverse impacts on aquatic phototrophic organisms. Comparative studies on microalgae species response to ZnO NPs and variation in tolerance among species is still mostly unexplored. The proposed research aims to evaluate interspecies’ variation in tolerance to ZnO NPs among …

Habitat Use Of Three Abundant Predatory Fish Species In The Freshwater Marshes Of The Florida Everglades, Alex T. Ontkos

FIU Electronic Theses and Dissertations

The Florida Everglades presents a model setting for studying animal-habitat relationships in a dynamic landscape that is heavily influenced by seasonal hydrology and water management. I used dynamic, high-resolution habitat classification maps and radio-telemetry to examine habitat preference of Largemouth Bass, Bowfin, and Florida Gar before and after a field-scale manipulation was established to address uncertainties with Everglades restoration and water management practices. Results indicate preference for the canal habitat by all three species, which represents only a small portion of the submerged landscape even in the driest conditions. Bowfin and Florida Gar were more likely to be relocated within …

Novel Role Of Pseudomonas Aeruginosa Lptd Operon, Sundar Pandey

FIU Electronic Theses and Dissertations

Pseudomonas aeruginosais an opportunistic pathogen that infects cystic fibrosis (CF) patients contributing to their high morbidity and mortality. P. aeruginosaundergoes a phenotypic conversion in the CF lung, from nonmucoid to mucoid, by constitutively producing a polysaccharide called alginate. These mucoid strains often revert to nonmucoid in vitrodue to second-site suppressor mutations. We hypothesized that mapping these mutations would lead to the identification of novel genes involved in alginate production. In a previous study, a mucoid strain, PDO300 (PAOmucA22), was used to isolate suppressors of alginate phenotype (sap). One of the uncharacterized nonmucoid revertants, …

Spatial And Temporal Patterns Of Arctic Nearshore Fish Community And Food Web Structures, Mark B. Barton

FIU Electronic Theses and Dissertations

Climate change and increasing anthropogenic activities are causing rapid changes to environmental and ecological processes in the Arctic Ocean. To better understand these changes, scientists have increased research efforts in these regions, but to date the number of studies on Arctic nearshore habitats are lacking. My dissertation responds to the paucity of information and investigates patterns in Arctic nearshore fish communities and food webs to gain insight to how these ecosystems may shift as these changes continue. I used multivariate statistical analysis to examine patterns in community structure and composition to determine that Arctic nearshore fish communities are largely driven …

Quantitative Spatial Upscaling Of Categorical Data In The Context Of Landscape Ecology: A New Scaling Algorithm, Daniel Gann

FIU Electronic Theses and Dissertations

Spatially explicit ecological models rely on spatially exhaustive data layers that have scales appropriate to the ecological processes of interest. Such data layers are often categorical raster maps derived from high-resolution, remotely sensed data that must be scaled to a lower spatial resolution to make them compatible with the scale of ecological analysis. Statistical functions commonly used to aggregate categorical data are majority-, nearest-neighbor- and random-rule. For heterogeneous landscapes and large scaling factors, however, use of these functions results in two critical issues: (1) ignoring large portions of information present in the high-resolution grid cells leads to high and …

Structure-Function Relationships In Hexacoordinate Heme Proteins: Mechanism Of Cytoglobin Interactions With Exogenous Ligands, Antonija Tangar

FIU Electronic Theses and Dissertations

Cytoglobin (Cygb) and neuroglobin (Ngb) are among the newest members of vertebrate globin family characterized by a classical 3-over-3 α-helical fold and a heme prosthetic group capable of reversibly binding small ligands such as O₂, CO and NO. The physiological functions of Cygb and Ngb remain to be determined; however, current data suggest that both proteins have a significant role in cytoprotection in hypoxic and genotoxic conditions. Cytoglobin and Ngb are distinct from their better-known counterparts, hemoglobin (Hb) and myoglobin (Mb), in several structural features. First, in the absence of an external ligand, the sixth coordination site of …

Saltwater Intrusion And Vegetation Shifts Drive Changes In Carbon Storage In Coastal Wetlands, Sean Patrick Charles

FIU Electronic Theses and Dissertations

Coastal wetlands protect coastlines through efficient storage of organic carbon (OC) that decreases wetland vulnerability to sea level rise (SLR). Accelerated SLR is driving saltwater intrusion and altering vegetation communities and biogeochemical conditions in coastal wetlands with uncertain implications. We quantified changes in OC stocks and fluxes driven by 1) saltwater and phosphorous intrusion on freshwater and brackish marshes, 2) vegetation along an experimental saltmarsh to mangrove gradient, 3) saltwater intrusion and vegetation change across a marsh to mangrove ecotone, and 4) vegetation change and mangrove forest development along a marsh to mangrove ecotone. Increasing salinity in freshwater marshes decreased …

The Real Snowbirds Of South Florida: Using Citizen Science To Assess The Ranges Of South Florida's Overwintering Birdsh, Alexander V. Levine

FIU Electronic Theses and Dissertations

The overwintering ranges of North American bird populations are shifting and the winter ranges of south Florida’s landbirds remain understudied. Expert-drawn range maps used for scientific studies and environmental public policy could therefore be depicting inaccurate ranges for many migratory birds. This study used citizen science data from eBird (2001–2017) to evaluate patterns in overwintering avian species richness and identify discrepanciesin expert-drawn species range maps for overwintering passerines in south Florida. Most of Florida’s overwintering bird species were sighted in south Florida. Of the species observed there between 2001 and 2017, 66% had range map discrepancies. Fifteen target species were …

Modulating Adipogenesis: Key Role Of Ras-Related Protein Rab5 And Its Effectors, Yongjun Huang

FIU Electronic Theses and Dissertations

The formation of adipocytes is a complicated process in which insulin and IGF-1 signaling pathways and numerous transcription factors control the conversion of precursor cells to mature fat cells. The Rab5 protein acts as a rate-limiting protein during receptor-mediated endocytosis by switching between a GDP-bound inactive form and a GTP-bound active form. The inactivation and activation of Rab5 are regulated by several Rab5 GTPase activating proteins (GAPs) and Rab5 guanine nucleotide exchange factors (GEFs), respectively.

This dissertation demonstrated that the activity of the small GTPase Rab5 and its regulators are essential for the differentiation of 3T3-L1 pre-adipocytes. Specifically, it showed …

The Effect Of Microbial Growth On The Spectral Induced Polarization Response In Hanford Vadose Zone Sediment In The Presence Of Autunite, Alejandro Garcia

FIU Electronic Theses and Dissertations

Uranium contamination of the subsurface remains a significant problem at the Department of Energy Hanford site. A series of column experiments were conducted on Hanford sediment saturated with simulated groundwater to study the effects of aqueous bicarbonate and microbial growth on the mobility of Uranium. Spectral induced polarization (SIP) measurements in the columns were conducted concurrently with pore water sampling in order to monitor changes occurring inside the sediment after the initiation of microbial growth induced by glucose injection. The microbial growth caused significant increases in the real component of the complex conductivity and is the result of ion release …

Impact Of San-Mediated Signaling On Glioblastoma And Neuroblastoma Metabolism, Monica Rodriguez Silva

FIU Electronic Theses and Dissertations

Glioblastoma (GBM) is the most common and aggressive type of brain cancer, with an average life expectancy of 15 months. The standard of care for GBM, surgery accompanied by radiation and chemotherapy (temozolomide-TMZ), has not changed in over 10 years illustrating the need for new and efficacious treatments. Therefore, it is imperative to improve our knowledge of GBM physiology to understand the mechanisms driving recurrence and chemoresistance so that more effective therapeutic options can be developed. Mitochondria-cell communication is key to monitor and maintain both mitochondrial and cellular health, and signaling events on the outer mitochondrial membrane (OMM) have emerged …

Developing Ocean Color Algorithm Using Moderate Resolution Imaging Spectroradiometer (Modis) Sensor For Shallow Coastal Water Bodies, Mohd Manzar Abbas

FIU Electronic Theses and Dissertations

This study analyses the spatial and temporal variability of chlorophyll-a in Chesapeake Bay; assesses the performance of Ocean Color 3M (OC3M) algorithm; and develops a novel algorithm to estimate chlorophyll-a for coastal shallow water. The OC3M algorithm yields an accurate estimate of chlorophyll-a concentration for deep ocean water (RMSE=0.016), but it failed to perform well in the coastal water system (RMSE=23.17) of Chesapeake Bay. A novel algorithm was developed which utilizes green and red bands of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. The novel algorithm derived the chlorophyll-a concentration more accurately in Chesapeake Bay (RMSE=4.20) than the OC3M algorithm. …

Transcription Factor 7-Like 2 (Tcf7l2) Gene Polymorphisms In Relation To The Risk Of Type 2 Diabetes In Three Ethnicities, Ling Xu

FIU Electronic Theses and Dissertations

Type 2 Diabetes (T2D) disproportionally affects ethnic minorities in the United States. The development of T2D involves complex interaction between environmental factors and genetic predisposition. The genetic associations of six single nucleotide polymorphisms (SNPs) in TCF7L2 gene with the risk of T2D were evaluated in three high risk minority populations: Cuban Americans, Haitian Americans, and African Americans. For Cuban Americans, four SNPs (rs7901695, rs4506565, rs7903146 and rs11225537) were significantly associated with the risk of T2D after multivariable adjustment (p=0.018, p=0.016, p=0.014, and p=0.0008, respectively). Among controls, risk allele carriers of SNPs rs7901695, rs4506565 and rs7903146 had significantly higher fasting glucose …

Evolutionary And Population Dynamics Of Crustaceans In The Gulf Of Mexico, Laura Timm

FIU Electronic Theses and Dissertations

Evolution occurs and can be conceptualized along a spectrum, bounded on one extreme by the relationships between deep lineages – such as phyla, classes, and orders – and on the other by the molecular dynamics of operational taxonomic units within a species, defined as population genetics. The purpose of this dissertation was to better understand the evolutionary and population dynamics of crustaceans within the Gulf of Mexico. In the second chapter of my dissertation, I provide a guide to best phylogenetic practice while reviewing infraordinal relationships within Decapoda, including the promise held by next-generation sequencing (NGS) approaches such as Anchored …

Regulation Of Juvenile Hormone Synthesis By 20-Hydroxyecdysone In The Yellow-Fever Mosquito, Aedes Aegypti, Maria Areiza

FIU Electronic Theses and Dissertations

In Aedes aegypti, development and reproduction are regulated by juvenile hormone III (JH). This master regulatory hormone is synthesized by the corpora allata (CA), a pair of endocrine glands with neural connections to the brain. JH titers are largely determined by the rate of biosynthetic activity of the CA and are regulated by inhibitory and stimulatory factors. Like JH, the ecdysteroid 20-hydroxyecdysone (20E) is a key hormonal regulator and has been proposed as an allatoregulator in other insects. However, its part in the regulation of JH biosynthesis of mosquitoes was unknown. The specific aims of this dissertation were to …

Structure And Mechanism Of Mycobacterial Topoisomerase I, Nan Cao

FIU Electronic Theses and Dissertations

The enzyme DNA topoisomerase I is an essential enzyme that plays an important role in eukaryotic and prokaryotic cellular processes such as DNA replication, transcription, recombination and repair. Mycobacterium tuberculosistopoisomerase I (MtTOP1) is a validated drug target for antituberculosis treatment. Mycobacterial topoisomerase I regulates the topological constraints in chromosomes and helps in maintaining the growth of mycobacteria. The N- terminal domain (NTD) of mycobacterial topoisomerase I contains conserved catalytic domains that along with the active site Tyrosine are involved in cleaving and rejoining a single strand of DNA. Magnesium is required in DNA cleavage activity of type IA topoisomerases. …

The Use Of Elemental Databases In Forensic Science: Studies On Vehicle Glass Interpretation And Milk Powder Provenancing, Tricia Marie Hoffman

FIU Electronic Theses and Dissertations

The first study focuses on the development of a laser based method for the elemental analysis of solid milk powder. Milk powder samples originating from five different countries were analyzed to determine any geographic differences. A LA-ICP-MS method was developed and compared to k₀-INAA for several milk samples as well as a reference sample. Precision of 10% RSD or better and a bias of 10% was achieved for both techniques for most elements with LA-ICP-MS producing lower limits of detection (~ 1 ppm) for Sr. The comparison of LA-ICP-MS to k₀-INAA showed overlap of the 95% …