Life Sciences Commons^™

Conservation Of South Florida Orchid Mycorrhizal Fungi, Ellen Garcia

FIU Electronic Theses and Dissertations

Starting in the late 1800’s orchids were heavily poached, leaving many species to reach critically low numbers. Coupled with habitat loss and urbanization many orchid populations were extirpated in southern Florida. Due to lack of endosperm, orchid seeds are reliant on specific mycorrhizal fungi to obtain nutrients to enable growth and development resulting in very low germination rates in nature. The obligate relationship on mycorrhizal fungi complicates orchid re-establishment. The research project aims are (1) to evaluate the correlation between phenotypic traits and optimal growing conditions in various micro-climate, and (2) to assess the range of mycorrhizal fungi community in …

High And Low Toxin Producing Strains Of Karenia Brevis Differ Significantly In The Redox Proteome, Lipid Profiles, And Xanthophyll Cycle Pigments, Ricardo Colon

FIU Electronic Theses and Dissertations

The dinoflagellate Karenia brevis, blooms annually in the Gulf of Mexico, producing a suite of neurotoxins known as the brevetoxins. The cellular toxin content of K. brevis, however, is highly variable between or even within strains. I investigated biochemical differences between high (KbHT) and low (KbLT) toxin producing cultures both derived from the Wilson strain, related to energy-dependent quenching (qE) by photosystem II, and the content of reduced thiols of the proteome. By characterizing the xanthophyll content of the two strains I was able to determine that KbLT performs qE inconsistently. To investigate the …

Purine Nucleosides Modified At C8 Or C2 Position With (Β-Halo)Vinylsulfone And Β-Ketosulfone Reactive Groups And Their Incorporation Into Dna: Synthesis Of The Organoarsenical Antibiotic Arsinothricin And Polyaromatic Hydrocarbons, Md Abu Hasan Howlader

FIU Electronic Theses and Dissertations

Modified nucleosides gained great attention as potential anticancer and antiviral therapeutics. In this dissertation, synthesis and reactivity of (β-iodovinyl)sulfone and β-ketosulfone groups incorporated into purine nucleosides at C8 or C2 positions and DNA incorporation of their 5' triphosphates have been developed. Moreover, synthesis of novel antibiotic arsinothricin (AST) as well as polycyclic aromatic hydrocarbons (PAHs) have been discussed. The 8-(1-iodo-2-tosylvinyl)-2'-deoxyadenosine and 8-(1-Iodo-2-tosylvinyl)adenosine were synthesized employing iodovinylsulfonation of 8-ethynyl precursors with TsNa/I₂/NaOAc. The 8-(β-iodovinyl)sulfonyl-2'-deoxyguanosine was prepared via radical mediated iodovinylsulfonation of 8-ethynyl-2'-deoxyguanosine with TsNHNH₂/KI/(BzO)₂. Conformationally different C2 substituted isomeric adenosine analogues were prepared by iodovinylsulfonation …

Type I Topoisomerases As Potential Targets For Therapeutics, Ahmed Seddek

FIU Electronic Theses and Dissertations

DNA topoisomerases are universal enzymes that control the topological features of DNA in all forms of life. This study aims to find potential inhibitors of some of the DNA topoisomerases in bacteria and humans that can be developed into potential therapeutics.

The first aim of this study is to find potential inhibitors of bacterial topoisomerase I that can be developed into antibiotics. There is an urgent need to develop novel antibiotics to overcome the world-wide health crisis of antimicrobial resistance. Virtual screening and biochemical assays were combined to screen thousands of compounds for potential inhibitors of bacterial topoisomerase I. NSC76027 …

Effects Of A Cooking And Gardening Nutrition Intervention In Food Insecure College Students, Alison K. Macchi

FIU Electronic Theses and Dissertations

As higher education becomes more attainable to all populations, college students from low-income backgrounds are at an increased risk of food insecurity due to the financial burdens that come with the transition to college. Food insecurity on U.S. college campuses ranges up to 59%, quadrupling the average national household food insecurity rate of 14%. In college students, food insecurity is correlated with unhealthy eating, alcohol use, and mental health issues.

The aim of this study was to develop and examine the feasibility and promise of a Social Cognitive Theory based, urban gardening, cooking and nutrition education intervention on health behavior …

Understanding Individual Differences Within Large-Scale Brain Networks Across Cognitive Contexts, Katherine L. Bottenhorn

FIU Electronic Theses and Dissertations

Historically, human neuroimaging has studied brain regions “activated” during behavior and how they differ between groups of people. This approach has improved our understanding of healthy and disordered brain function, but has two key shortcomings. First, focusing on brain activation restricts how we understand the brain, ignoring vital, behind-the-scenes processing. In the past decade, the focus has shifted to communication between brain regions, or connectivity, revealing networks that exhibit subtle, consistent differences across behaviors and diagnoses. Without activation-focused research’s constraints, connectivity-focused neuroimaging research more comprehensively assesses brain function. Second, focusing on group differences ignores substantial within-group heterogeneity and often imposes …

An Information Theoretic Approach To Characterizing The Attention Shifts In The Fruit Fly During Flight, Nicholas A. Palermo

FIU Electronic Theses and Dissertations

To successfully navigate the complex visual world, animals must extract relevant information from the deluge of light-carried signals that arrive at their eyes. Early vision filters are passive, energy-saving gates that block out irrelevant signals. The remaining incoming signals are then subject to active filtering by visual attention systems which are energetically expensive, especially for smaller animals, which are subject to similar survival challenges as larger animals.

Among visual behaviors performed by insects, flight stabilization demands one of the highest rates of information uptake. Flying insects must quickly respond to flight disturbances to avoid navigation errors and collisions. Active flight …

Epigenetic Mechanisms As Drivers Of Environmental Responses In Stony Corals, Javier A. Rodriguez Casariego

FIU Electronic Theses and Dissertations

The current pace of anthropogenic global change is imposing unprecedented conditions to biological systems. Coral reef ecosystems are particularly sensitive to the rapid increase in thermal anomalies and the changes in water chemistry caused by global change. However, although their decline has been documented worldwide, there are signs suggesting that stony corals harbor greater phenotypic plasticity than previously expected, sparking the interest in the study acquired non-genetic modifications (e.g., epigenome, microbiome) potentially increasing their resilience to global change, and constituting one of the main targets for intervention.

Epigenetics constitutes an exciting frontier to understand how the environment influences the regulation …

In Situ Arsenic Speciation Using Surface-Enhanced Raman Spectroscopy And The Coffee Ring Effect, Valery Liamtsau

FIU Electronic Theses and Dissertations

The coffee ring effect (CRE) phenomenon is originated from the nonuniform solvent evaporation of a sessile droplet deposited onto the flat substrate. Once the evaporation starts, the droplet suspended particles move outwards by the radial flow and concentrate in the edge region of the evaporating droplet, resulting in the formation of the so-called CRE stains. In this work we have expanded the applications of the CRE from separation of particles and macromolecules to small molecules, in particular, coupled to surface-enhanced Raman spectroscopy (SERS). Herein, we have developed a theoretical framework to describe the CRE-driven separation process of small molecules, using …

Neurobiological Impact Of Hiv Infection And Chronic Cannabis Use, Jessica Shannon Flannery

FIU Electronic Theses and Dissertations

Neuroimaging research has identified brain alterations linked with the human immunodeficiency virus (HIV) that contribute to cognitive declines characterizing the disease. Given cannabis’s (CB’s) anti-inflammatory properties, use prevalence among people living with HIV (PLWH), and impact on neurocognition, my dissertation utilizes a between-groups study design to interrogate separate and interactive effects of HIV and CB on fMRI measures of brain activity. We investigate (1) task-based brain activity at the regional-level, (2) insular resting-state functional connectivity (rsFC) at the circuit-level, and (3) large-scale brain network interactions at the systems-level. Participants (N=114) were stratified into four groups (HIV+/CB+; HIV+/CB-; HIV-/CB+; HIV-/CB-) and …

Exercise, Cognition, And Cannabis Use In Adolescents, Ileana Pacheco-Colón

FIU Electronic Theses and Dissertations

Heavy and/or chronic cannabis use has been associated with neurocognitive impairment and decline, often in domains such as memory and executive functioning. On the other hand, exercise has been linked to positive effects on brain and cognitive health across the lifespan, as well as to better substance use outcomes. Despite this, little is known about the ways in which exercise could help prevent or ameliorate adverse cannabis-related outcomes among adolescents.

Through three separate studies, the current dissertation examines interrelations among exercise, cognition, and cannabis use in children and adolescents in an effort to determine whether exercise can prevent or ameliorate …

Taxonomy And Systematics Of Plumeria L. (Apocynaceae) In The Caribbean Islands, Nichole M. Tiernan

FIU Electronic Theses and Dissertations

Plumeria L. (Apocynaceae) is a genus of flowering trees and shrubs that are often cultivated in tropical gardens worldwide. The majority of its species occur in the Greater Antilles with many as single-island endemics. The only comprehensive revision for the genus was done by Robert E. Woodson Jr. (1937) who recognized only seven species and created a ‘Plumeria obtusa complex’ with a plethora of synonyms. The first study provides an overview of the Caribbean Island members of the genus with a focus on Plumeria filifolia Griseb., a thin-leaved species endemic to Cuba that is featured because of its incredible …

Invasion Ecology And Response To Fire Of The Nonnative Fern Lygodium Microphyllum In The South Florida Everglades, Nicole Sebesta

FIU Electronic Theses and Dissertations

Lygodium microphyllum (Old World Climbing Fern (OWCF)) is a climbing fern native to tropical and subtropical regions of Australia, Asia, and Africa. First introduced to Florida as an ornamental in the 1960s, the fern has become a serious invasive in numerous Florida habitats, severely degrading native herbaceous and woody vegetation and altering fire behavior. One area with the greatest increase in OWCF cover is the sawgrass marsh of southern Everglades National Park (ENP), where prescribed fire is used for both maintenance of sawgrass marshes and management of OWCF infestations. However, the efficacy of OWCF control using fire in this habitat …

Uncharacterized Isosporoid Parasite In The Florida Grasshopper Sparrow (Ammodramus Savannarum Floridanus), Matthew S. Morris

FIU Electronic Theses and Dissertations

A novel and potentially fatal isosporoid parasite was discovered within a captive population of Florida Grasshopper Sparrows, kept at the Rare Species Conservatory in Loxahatchee, Florida. The purpose of this thesis was to (1) to ascertain the prevalence of the Isospora sp. in the captive population of FGSPs; (2) to show that the pathogen can cause both morbidity and mortality in the FGSP; (3) to use population modeling as a management tool to show the potential effects of the disease on the wild population; and (4) recommend mitigation and management strategies informed by our research. Overall, histopathology and necropsy reports …

Evaluation Of Harvesting Time For Industrial Hemp (Cannabis Sativa L,) Pilot Project Varieties Grown In South Florida, Jordan W. Prats

FIU Electronic Theses and Dissertations

A field study was conducted to observe the natural development of cannabinoids in three daylength sensitive industrial hemp varieties Bubba Kush (BK), Emerald Flower (EF), and Golden Sunset (GS). Plants were configured in a randomized block design with 3 replications. Once 50% of the plants within a variety reached reproductive growth, plants were sampled weekly until senescence and analyzed through a HPLC-UV/DAD. The results from the study indicate that all three varieties of industrial hemp tested in field study reached reproductive growth within the first week of transplanting. This is due to a 12-hour day-length at the time and the …

Identification Of Human Topoisomerase I Poison And Catalytic Inhibitors, Christian Madeira

FIU Electronic Theses and Dissertations

Inhibition of human topoisomerase I have been shown to reduce excessive transcription of PAMP-induced genes based on prior studies, which offers a solution to offset complications of sepsis such as tissue damage and organ failure. The enzyme resolves the topological constraints on DNA that encodes these genes. The aim of this study is to identify human topoisomerase I (HTop1) inhibitors that can a.) prevent the relaxation of negative supercoiled plasmid DNA by HTop1 and b.) reduce HTop1 binding to DNA and formation of covalent cleavage complex (HTop1cc) utilizing a novel yeast screening system. Top hits from in-silico screening conducted by …

Gender Differences, Vitamin B6, Polyunsaturated Fatty Acids, And Inflammation-Related Diseases, Hyojung Kim

FIU Electronic Theses and Dissertations

Vitamin B6-restricted diets and low plasma pyridoxal 5'-phosphate (PLP) status altered plasma polyunsaturated fatty acids (PUFA) compositions. The relationship of aging with vitamin B6 status and PUFA metabolism is poorly understood. This dissertation explored the association between vitamin B6 intake and status and plasma PUFA in US young/middle-aged adults and in older adults from NHANES 2003-2004. Future research plans will examine the relationships among vitamin B6, PUFA, inflammatory diseases, including chronic liver diseases; however, there is a gap in plasma PLP data in the Miami Adult Studies in HIV (MASH) cohort data on these relationships. Thus, the relationship between substance …

Comparison Of Modern And Mid-Holocene Benthic Foraminifera To Assess Recent Environmental Change In Almirante Bay, Caribbean Panama, Maria N. Gudnitz

FIU Electronic Theses and Dissertations

This study used the diversity and distribution of benthic foraminiferal assemblages of Almirante Bay, Caribbean Panama, as environmental proxies to compare modern coral, seagrass and mangrove habitats to mid-Holocene coral reef facies on the island of Isla Colón, to investigate both natural and human-influenced changes.

The modern study associated species and assemblage characteristics with environmental conditions related to degraded water quality. Assemblages were fairly similar among neighboring habitats but differed in species proportions, while several stress-tolerant taxa might indicate eutrophic conditions. Diversity appeared to be regionally controlled by freshwater input irrespective of habitat type, was generally lower near the mainland …

Density Dynamics Of Endosymbiotic Wolbachia Bacteria In The Drosophila Host, Zinat Sharmin

FIU Electronic Theses and Dissertations

Wolbachia pipientis is one of the most widespread bacterial endosymbionts, infecting mites, crustaceans, and filarial nematodes as well as about half of all insect species. These bacteria cause many neglected human diseases that include African river blindness and lymphatic filariasis affecting over 100 million people worldwide. Interestingly, Wolbachia also suppress the transmission of viruses such as Dengue, Chikungunya, and Zika. In most reported cases, Wolbachia antiviral activity is a density-dependent effect, with high Wolbachia density conferring the strongest viral suppression. However, little is currently known about how Wolbachia load is controlled within the insect host. A small number of studies …

Developing Sustainable Soil Building Strategies For Tropical Fruit Groves Within The South Florida Redland, Ariel Freidenreich

FIU Electronic Theses and Dissertations

Tropical fruit production has become a lucrative industry in Miami-Dade County. Consequently, developing sustainable farming practices to be applied to these systems to ensure healthy soils and economically viable fruit production is becoming increasingly important. The study is focused on the incorporation of cover cropping as a management strategy for perennial tropical fruit production and its applications for local growers. Cover crops are plants that are grown to cover soil to reduce erosion, increase soil fertility, and enhance farmland biodiversity. The project was specifically designed to test the impacts of highly prolific legumes sunn hemp (Crotalaria juncea) and …

Functional Regionalization In The Fly Eye As An Adaptation To Habitat Structure, Carlos A. Ruiz

FIU Electronic Theses and Dissertations

With over 150,000 described species, flies constitute one of the most species-rich groups of animals on earth, and have managed to colonize almost every corner of it. Part of their success comes from their amazing flying skills, which are strongly tied to their visual capabilities. To navigate fast and accurately through their habitats, they must be able to process the inordinate amounts of visual information necessary to sort obstacles, avoid predators and remain on course. Surprisingly, despite their tiny brains, flies have no problem in processing all that information to generate correcting maneuvers in just about 30 ms. To this …

Food Insecurity Is Associated With Nonalcoholic Fatty Liver Disease, Cognitive Impairment, And Immune Activation In People Living With Hiv, Javier A. Tamargo

FIU Electronic Theses and Dissertations

Food insecurity (FI) is a socioeconomic condition characterized by inadequate access to enough food and nutrition to sustain health and wellbeing. Food insecurity is a risk factor for chronic and age-related conditions, raising concerns for the aging population of people living with HIV (PLWH), in whom food insecurity is disproportionately prevalent. PLWH are at increased risk of nutrition-related complications and chronic co-morbidities, thus food insecurity may exacerbate adverse health outcomes in this population. This study investigated whether food insecurity was associated with nonalcoholic fatty liver disease (NAFLD), cognitive impairment, and immune activation among socioeconomically disadvantaged adults living with and without …

A Web-Based Nutrition Education Intervention For Asian Indian Fathers In Florida, Priya Krishnakumar

FIU Electronic Theses and Dissertations

Research has shown that fathers, like mothers, are an important influence for forming children’s dietary and physical activity habits. Fathers’ nutrition knowledge, attitudes and child feeding practices impact children’s eating behavior and future weight status. Yet very few interventions have focused on targeting fathers for childhood obesity prevention by improving their knowledge and confidence in establishing healthy eating patterns in children. The limited studies existing in this area have focused on other ethnicities and data is missing on Asian Indians, the third largest immigrant Asian group in the United States. Asian Indian children are at equal risk for developing obesity …

Growth Of Diatom Fistulifera Alcalina In Bacterial Co-Culture And Comparative Mitogenomics Of Fistulifera Species, Erwin David Berthold

FIU Electronic Theses and Dissertations

Diatoms are excellent biological models of growth and intracellular oil generation. The productivity and compounds of diatoms, especially oils, support aquatic food chains and human medical and industrial needs. The qualities that made diatoms prolific producers, specifically diatom physiological features such as growth rates with intracellular lipid storage in alkaline environments, are however poorly understood. Another physiological aspect that remains unexplored is the effects of bacteria on the growth and lipid production of alkaliphilic diatoms. More studies, especially co-cultures, are needed for advances in diatom biology and strain performance for the algal biotechnological field. Besides physiology, diatom genetics using next-generation …

Carbon Storage Of Restored Mangrove Forests In Biscayne Bay, Florida, Daniel Chomin-Virden

FIU Electronic Theses and Dissertations

Space-for-time substitution was used to evaluate the rate of carbon storage in three carbon pools (aboveground, belowground, and soil organic carbon) across four restored mangrove forests in Biscayne Bay, Florida, USA. The restored forests ranged in age from 8 to 20 years. Diameter at breast height was used to estimate aboveground biomass. Belowground biomass and soil carbon were determined using 15 cm soil cores. Time to equivalence was calculated for the sites by reference to geographically proximate natural mangrove forests. Time to equivalence in aboveground and belowground biomass were 50.4 and 13.6 years, respectively. Soil organic carbon and total carbon …

Possum Trot History: A Historical Perspective On Barnum Groves And Possum Trot Tropical Fruit Nursery, Robert Barnum, Beverly Barnum

Possum Trot

This document provides an in-depth look at the development and management of Barnum Groves and Possum Trot Tropical Fruit Nursery. Covering topics such as land acquisition, family history, farm infrastructure, and the agricultural legacy of the Barnum family, it traces the evolution of the farm from its early days to its modern operations. The narrative delves into significant events like Hurricane Andrew, the family's involvement in local agriculture, the farm's regenerative farming techniques, and its role in South Florida's tropical fruit industry. It also highlights personal stories, the establishment of farm buildings, and the challenges faced in maintaining the farm’s …

A Comparative Genomics Exploration Of Inter-Partner Metabolic Signaling In The Coral-Algal Symbiosis, Katherine E. Dougan

FIU Electronic Theses and Dissertations

At the foundation of coral reef ecosystems is the symbiosis between the coral host and its microbial community, particularly its photoautotrophic algae from the family Symbiodiniaceae. As a symbiosis centered around nutritional exchange, determining the mechanisms involved in the maintenance of this cooperative exchange is central to understanding how it breaks down. As the nutritional transfer primarily consists of sugars, this work first focuses on the cnidarian insulin signaling pathway, an evolutionarily important metazoan pathway involved in diverse functions, most notably metabolism. This dissertation unveiled 360 putative cnidarian insulin-like peptides (cnILPs) from existing transcriptomic datasets, where they were previously missed …

Bacterial Mechanisms Of Toxicity And Resistance To Organoarsenicals, Luis D. Garbinski

FIU Electronic Theses and Dissertations

Arsenic is a toxic element prevalent in the environment since the origin of life on Earth. Bacteria evolved in an arsenic-rich environment, where they developed ways to both overcome arsenic toxicity and harness it to compete with other organisms. These mechanisms include chemical modifications (e.g. oxidation, methylation), degradation, and efflux. The goal of this dissertation is to better characterize these mechanisms, illuminating the arsenic biogeocycle and allowing us to harness organoarsenical toxicity for novel antibiotics. A goal of my research was to elucidate the antibiotic properties of MAs(III), which is synthesized by bacteria to thrive over other bacteria, by identifying …

Production And Characterization Of Twelve Different Biochars And Evaluating Their Effects On Soil Health And Plant Growth, Shagufta Gaffar

FIU Electronic Theses and Dissertations

Biochar has been a topic of growing interest in the scientific community. It is a product derived from carbon rich organic materials through the process of pyrolysis. It has received wide attention as a means to improve soil fertility and crop productivity, absorb pollutants in soil, and sequester carbon to mitigate climate change. Recent research on biochar explores its impacts on the environment with particular focus on use as a soil amendment in agriculture. Biochar produced from different biomass and under different production process effects the environmental and agronomic impacts of its application in different ways. This means biochar can …

Connections In The Underworld: A Morphological And Molecular Study Of Diversity And Connectivity Among Anchialine Shrimp., Robert Eugene Ditter

FIU Electronic Theses and Dissertations

This research investigates the distribution and population structure of crustaceans, endemic to anchialine systems in the tropical western Atlantic focusing on cave-dwelling shrimp from the family Barbouriidae. Taxonomic and molecular tools (genetic and genomic) are utilized to examine population dynamics and the presence of phenotypic hypervariation (PhyV) of the critically endangered species Barbouria cubensis (von Martens, 1872). The presence of PhyV and its geographic distribution is investigated among anchialine populations of B. cubensis from 34 sites on Abaco, Eleuthera, and San Salvador, Bahamas. Examination of 54 informative morphological characters revealed PhyV present in nearly 90% (n=463) of specimens with no …