Biology Commons^™

Optimization Of In-Vitro Tissue Culture And Transformation System For Sweet Sorghum Cultivars Using Immature Inflorescence, Logayn Abushal

Theses and Dissertations

Background: Sweet sorghum is a multi-purpose crop that can be used for human food, animal feed, and bio-fuel production. This crop is drought-tolerant and can therefore be grown in arid and semi-arid regions especially in marginal areas in Egypt. Nevertheless, production of Sweet sorghum cannot coup with the increasing demand in consumption as a food, and fuel due to a lag in scientific research regarding its genetic improvement. Therefore, genetic improvement of Sweet sorghum is innately required so that new traits of economic importance could be introduced; however, this can only be achieved through the establishment of a robust in-vitro …

Functional Characterization Of Arabidopsis Synaptotagmin-4 Protein Through Reverse Genetics Strategy, Zahid Jawed

Theses and Dissertations

Calcium ion plays a significant role in plant signal transduction pathways, including regulation of stress-induced gene expression. Sensor proteins such as proteins with calcium-binding C2 domains can perceive changes in cellular calcium level. Functional analysis of such sensor proteins will give us a better understanding of plant stress signaling. Synaptotagmins are a group of proteins containing C2 domains that are capable of binding calcium ions and regulate gene expression in response to external abiotic stress stimuli. Here, we used a reverse genetic approach to analyze the function of synaptotagmin – 4, which is one of the five identified synaptotagmin proteins …

Active Targeting Of Estrogen Receptor (Er)-Positive Breast Cancer Cells Using Nanotechnology, Molly White

Theses and Dissertations

The American Cancer Society has predicted an estimated 281,550 new invasive breast cancer cases for 2021. Chemotherapy is one of the main options available to treat this disease, but it can result in drug resistance and harmful side effects, as traditional methods do not directly target the cancer cells. To address this issue, nano formulations have been widely researched for targeted delivery of anticancer drugs. The primary objective of this project was to develop a novel nanodrug, rapamycin-loaded gold nanorods functionalized with polyethylene glycol and epithelial cell adhesion molecule (EpCAM), to selectively target breast cancer cells. The work involved characterizing …

The Art Of Amphibian Conservation: Linking In-Situ And Ex-Situ Populations Of Endangered Species Through Genome Banking, Isabella Joann Burger

Theses and Dissertations

Limited breeding success in captive breeding programs has necessitated the development of assisted reproductive technologies (ART) to preserve and increase genetic variation and population numbers of both captive and wild amphibian groups. ART has been shown to be successful in numerous anuran species, and current studies focus on the application of ART in ex-situ populations. The focus of this project is to show that linking in-situ and ex-situ amphibian populations through sperm cryopreservation, genome banking, and in-vitro fertilization is possible, with the goal of increasing gene diversity throughout groups in order to produce self-sustaining, wild populations in the future. Specific …

Exploring The Role Of Stigmatic Exudate In The Water Lily (Nymphaceae) Pollination Mechanism Using N. Ampla (Salisb. Dc.), Luis Uribe

Theses and Dissertations

Water lilies are the only known plant group that uses hyperactive nectar glands to divest pollinators of their pollen. The nectar in Nymphaea ampla is thought to contain secondary metabolites that increase pollen deposition possibly by modifying pollinator behavior. This was explored utilizing visitation and fecundity data from the field coupled with survival and behavioral experiments in the laboratory. Replacing nectar with water reduced seed set in N. ampla which was attributed to reduced visitation in water-bearing flowers and not to effects on pollinator detention time. Exposure to nectar did not reduce survivability in Apis mellifera. Pollen and nectar foragers …

Characterization Of Soil Nematode Community As Influenced By Weedy Plants And Edaphic Properties, Orlando Garcia

Theses and Dissertations

Nematodes are one of the most critical species globally as they are part of most nutrient recycling. While nematodes play a vital role in nutrient cycling, little is known about them from an ecological standpoint. The majority of current research has focused on a singular component of the community, being those of herbivore/plant-parasitic nematodes. In this study, the community shifts of the nematode trophic groups were analyzed as influenced by native and invasive grasses species in the Lower Rio Grande Valley (LRGV) with the addition of edaphic soil properties.

In our study, the results indicate changes in the composition of …

Early Embryology In Collembola With An Emphasis On Wing Development, Samantha A. Gonzalez

Theses and Dissertations

The primary objective of this study was to further the understanding of the wing origin in insects. Currently there are several theories which are popular such as the tergum theory, the pleural plate theory, and the dual theory of wing origin. Studies for these theories have been done on crustaceans, the ancestors to modern day insects. By utilizing a pre insect hexapod, it may be possible to better understand the transition to insect wings. Members of the Collembola species Hypogastrurid are one of these pre-insect hexapods which may provide a clue into origins of wing development. During this study, the …

Prospecting For And Isolation Of Microalgae In South Texas, Mauricio Alejandro Peña

Theses and Dissertations

Microalgae is a very important microorganism that can be used for beneficial purposes for humans. One way to show the importance of algae in this planet is the contribution of Oxygen it provides to the atmosphere, which many organisms rely on (Medeiros et al., 2015). Carbon footprint has been one of the greatest causes for global warming and it is due to the use of fossils to create diesel. One of the ways to avoid contamination is to replace those fuels that are used on daily basis, such as for transportation. The microalgae are able to produce lipids that can …

Duet Phonology And Syntax Of The Red-Crowned Parrots In South Texas, Abigail Pozulp

Theses and Dissertations

Bird behavioral interaction systems show a preference for temporal precision. This preference is exemplified in the way many species avoid masking of vocal signals. Antiphonal duetting in songbirds suggest that overlapping notes are a sign of poor temporal coordination which can signify a weak pairbond, a possible cue for conspecifics seeking to usurp territories or mates. However, parrots (Psittacidae) are accomplished yet understudied duetters in nature. I recorded antiphonal duets produced by a wild population of red-crowned parrots (Amazona viridigenalis) in Brownsville, Texas. Temporal and acoustic variation of signals was assessed within and across a sample of mated …

Home Range Dynamics And Juvenile Dispersal Of Gray Hawks In The Lower Rio Grande Valley, Michael Stewart

Theses and Dissertations

Using GPS-GSM transmitters I determined when 14 juvenile Gray Hawks (Buteo plagiatus) in the Lower Rio Grande Valley of Texas fledged from their natal areas and how far they traveled once they dispersed. These transmitters also allowed me to calculate home range sizes for 22 adults. Additionally, with the GPS-GSM transmitters and 15 VHF transmitters, I discovered that adult Gray Hawks in the study area remained in their territories year-round. Home range sizes were calculated using the minimum convex polygon estimator, the estimation of kernel home-range, and the estimation of kernel Brownian bridge home-range. The same three methods allowed me …

Role Of Hsp70 And The Tlr4-Md2 Complex In The Vasculature: From Function To Dysfunction In Diabetes, Amanda Almeida De Oliveira

Theses and Dissertations

Diabetes impairs vascular functionality, which contributes to the pathophysiology of its associated complications. Recently, it was suggested that innate immune receptors assist in the development of diabetic vasculopathies, which sustains the pro-inflammatory state of the disease. Among these receptors, Toll-like receptor 4 (TLR4) is a strategic player as its activation prime the release of inflammatory mediators and reactive oxygen species (ROS), which are well-known pathological mechanisms linked to diabetic complications. The TLR4-Myeloid differentiation factor 2 (MD2) complex has gained much attention over the last decade, primarily because it interacts with self-produced molecules. In vascular tissues, the Heat-shock protein 70 (HSP70) …

Morphological Characterization And Functional Assessment Of Trichomes In Solanaceae, Sakshi Watts

Theses and Dissertations

Chapter 1: This chapter provides an overview of various trichome types in plants, and also empirically examines their variation on abaxial and adaxial leaf surface of 14 Solanum species. Detailed nomenclature, density, and dimension measurements of each trichome type has been provided using scanning electron-microscopy.

Chapter 2: Scanning electron microscopy was major component of methodology used in my thesis for scanning leaf samples to estimate trichome traits. In this chapter, a more efficient and cost-effective methodology for scanning electron microscopy has been explored.

Chapter 3: This chapter examines the relationship of trichome density and herbivore feeding behavior using abaxial and …

Algal Biodiversity Survey Of The Middle Chattahoochee River Using Dna Metabarcoding, Amanda Howell

Theses and Dissertations

Aquatic plants play vital roles in water systems by providing ecological services, and one group that is understudied is algae. Algae play a crucial role in water systems as bioindicators and primary producers. They can be challenging to identify with the naked eye, so researchers have been using DNA metabarcoding, where DNA belonging to specific taxa can be isolated and identified from water samples. The objective of this study was to conduct an algal biodiversity survey on the middle Chattahoochee River system in Georgia. Water samples (1L) were filtered and sent to RTL Genomics for sequencing and processing; the data …

Daphnia Pulex: The Mixed Messages Of Mutations , Matthew Randall Bruner

Theses and Dissertations

While mutations are almost universally considered to be more often deleterious than beneficial, their precise interactions between different populations and individual lines have been largely overlooked. Using mutation accumulation lines of four clones of obligately asexual Daphnia pulex, this research is intended to investigate the degree to which spontaneous mutation would affect fitness-related traits after roughly 100 generations. The expectation was that there would be a visible decrease in juvenile specific growth rate, the surrogate measurement used for fitness, across all four clones due to the deleterious nature of mutation in a selection free environment. Through measuring birth mass in …

Forest Structure, Above-Ground Carbon Stocks, And Productivity Along An Elevational Gradient In The Ecuadorian Andes, Esteban Pinto

Theses and Dissertations

The Andean forest provides a natural laboratory for evaluating long-term interactions between forests and variation in environmental parameters along elevational gradients. In particular, the mechanisms that control above-ground carbon stocks (AGC) and natural dynamics in mountain ecosystems constitute a potentially powerful tool for understanding the function of these ecosystems and their response to current climate change scenarios or past human disturbances. The present study integrates biotic (rarefied species richness and leaf traits) and abiotic (climate, soil properties and degradation) factors as possible drivers of AGC stocks, AGC net change (AGCnt), AGC productivity (AGCp) and AGC mortality (AGCk), along an elevational …

Heterogeneity In Multiple Inositol Polyphosphate Phosphatase1 (Minpp1): Identification And Characterization Of An Isoform-2 In Exosomes, Mohd Zubair

Theses and Dissertations

In pursuit of understanding the heterogeneity and physiological significance of multiple inositol polyphosphate phosphatase 1 (Minpp1), we have studied its isoforms for distinct motifs, subcellular distribution, and enzymatic potential. Initially, we took a Bioinformatics & Computational Biology approach exploring the proteome diversity of the Minpp1 utilizing the current NCBI database. We noticed three different minpp1 variants translated into three isoforms of Minpp1 proteins with varying molecular weight. A link between the minpp1 variant-2 gene and ER-stress, using real-time PCR, suggests a functional similarity between minpp1 variant-1 and variant-2. A detailed study on motifs revealed Minpp1 isoform-2 as the only other …

Drought-Tolerant Mechanisms Of Solanum Habrochaites, Dane Anthony Hudson

Theses and Dissertations

Understanding the complex mechanisms of drought tolerance in wild relatives of important crop plants offers a promising strategy for developing more stress resistant commercial cultivars. However, progress is limited by our understanding of the complex pathways involved in drought-tolerant phenotypes. This dissertation investigates and compares the biochemical and physiological effects of water deficit in a drought-tolerant wild tomato species (Solanum habrochaites) and a drought-sensitive commercial cultivar (Solanum lycopersicum cv. M82). M82 shows marked wilting reflected in low relative water content and water potential of the leaves, whereas S. habrochaites retains turgor, leaf water content, and high water potential levels. S. …

Investigation Of Techniques And Their Application For The Cryopreservation Of Algal Species, Jazmine Leija

Theses and Dissertations

An alternative source for petroleum-based crude oils are algae derived biofuels. Fossil fuels are harmful for the environment, expensive and becoming scarce. There has been an increase in research on environmentally sustainable energy, using lipids derived from microalgae, which can be converted into biofuel. The use of microalgae as a source for biofuels has a lot of benefits including decreasing greenhouse gas emissions, rapid fuel production, absorption of carbon dioxide, and production of a renewable source of energy.

Algae cryopreservation aids in the maintenance of the best algae strains selected for producing lipids for biofuels. Cryopreservation will help minimize genetic …

Effects Of Early Corticosterone Treatment On Vocal Babbling In Wild Green-Rumped Parrotlets (Forpus Passerinus), Celia Rose Mclean

Theses and Dissertations

The stress axis of the endocrine system allows for animals to respond to environmental stressors in contextually appropriate ways. Elevated levels of the stress hormone corticosterone (CORT) in male songbirds can result in compromised song learning ability. Parrots form a sister group to songbirds, but it is unknown whether CORT affects vocal development in parrots. The goal of this study was to assess the effects of CORT supplements in green-rumped parrotlets (Forpus passerinus), a free-ranging parrot species in Venezuela. Bouts of vocal babbling were extracted from nest box videos and analyzed. CORT supplementation resulted in differences in babbling …

Soil Chemistry Modification By Guinea Grass In Semi-Arid Soils: A Litter Mediated Positive Feedback, Vanessa Elizabeth Thomas

Theses and Dissertations

Nutrients are a key component of healthy soils. Their composition plays an important role in plant growth through nutrient cycling and directly influences the functioning of plant communities in both agricultural and natural ecosystems. Shifts in macronutrients such as phosphorus and nitrogen may be initiated by invasive growth as a driver for competition with native plants. The goal of this study is to explore the plant soil feedback in an exotic invasive plant, Guinea grass (Pancium maximum), an invasive bunch grass originally from Africa, across different habitat types in the Lower Rio Grande Valley (LRGV). To determine a positive plant …

Characterizing The Temporal And Spatial Distribution Of The Cannonball Jellyfish (Stomolophus Meleagris) In The South Atlantic Bight, Lauren G. Faulk

Theses and Dissertations

The cannonball jellyfish, Stomolophus meleagris, is commercially harvested throughout its range in the tropical and sub-tropical Americas, including in the South Atlantic Bight, where an estimated 4,000 tons (less than 2.4% of the estimated stock in South Carolina during the spring) are harvested annually. Like many Scyphozoan jellyfish, cannonball jellies have high interannual variability and little is known about the environmental drivers of their distribution and phenology. To better understand the ecology of this targeted species, we used fisheries-independent abundance data of cannonball jellyfish from 2001 to 2019 collected by the Southeast Area Monitoring and Assessment Program (SEAMAP) throughout the …

Human Cst (Ctc1-Stn1-Ten1) Promotes Topbp1 Stability And Chk1 Phosphorylation In Response To Telomere Dysfunction And Global Replication Stress, Stephanie Michelle Ackerson

Theses and Dissertations

Genomic DNA is constantly damaged by both internal and external genotoxins and cellular processes. A consequence of unrepaired or misrepaired DNA damage is genome instability, a hallmark of cancer and numerous other diseases. Eukaryotic cells have developed complex mechanisms to repair DNA damage, which is collectively referred to as a DNA damage response (DDR). CST (CTC1-STN1-TEN1) is a heterotrimeric, RPA-like protein complex that binds to single stranded (ss)DNA. In humans, CST functions in the replication and maintenance of telomeres, structures found at the ends of linear chromosomes, as well as non-telomeric DNA. Previous studies showed that deletion of the largest …

Genetic And Epigenetic Regulations Of Eds1-Mediated Plant Immunity And Identification Of Bacterial Type Iii Effectors Targeting De Novo Dna Methyltransferase Drm2 In Arabidopsis, Ming Zhao

Theses and Dissertations

In Arabidopsis thaliana, Enhanced Disease Susceptibility1 (EDS1) acts as an indispensable hub in plant immunity and is mainly responsible for plant basal defense, systemic acquired resistance (SAR), increase of endogenous content of salicylic acid (SA) and effector-triggered immunity (ETI). Epigenetic regulators play crucial roles in multiple important cellular processes. As one catalytic core of Polycomb Repressive Complex (PRC2), CURLY LEAF (CLF/SDG1) protein promotes H3K27me3 deposition at specific loci for genes repression. In this work, I found that EDS1 interacted with epigenetic regulators SDG1, SDG9, SDG15, SDG22 and SDG35 in yeast two-hybrid assays. The growth of the bacterial pathogen Pseudomonas …

Trans-Axonal Signaling And Activity-Dependent Mechanisms Of Topographic Mapping And Refinement In Vivo, Olivia Marie Spead

Theses and Dissertations

Brain connectivity and function depend on the precise formation of neuronal connections during development. In the central nervous system, most axonal projections are organized into topographic maps according to the spatial organization of the neurons they originate from or the type of stimulus they respond to. Topographic mapping is in large part established by interactions between axons and their target as well as by activity-dependent pruning of mistargeted or excessive arbors. Another important mechanism contributing to topographic map formation is pre-target axon sorting, where axons become pre-ordered en route to their destination. Both topographic mapping and pre-target sorting involve the …

The Development Of A Tractable System To Assess Caulobacter-Plant Interactions, Louis Berrios

Theses and Dissertations

Bacteria play an integral role in regulating plant growth and development. However, many of the mechanisms encompassing bacteria-plant interactions are poorly understood and thus require detailed assessments (see CHAPTER 1). To this end, I coupled bacterial (Caulobacter sp.) and plant model organisms (Arabidopsis) to determine 1) the degree to which select bacteria can enhance the growth and development of plants, and 2) what functions these bacteria possess that enable them to aid plant development. Employing bacterial isolation techniques, monoculture inoculum-based plant growth assays, biochemical assays, comparative genomics, functional genetics, and real-time quantitative PCR (RT-qPCR), I determined that …

Transcriptomic And Proteomic Identification Of Signaling Molecules Involved In Egg Activation In The Sea Star, Patiria Miniata, Lauren Shea Bates

Theses and Dissertations

During egg activation in all species, the critical mechanism to restart the zygote metabolism and prevent polyspermy is an intracellular Ca2+ increase. The signaling molecules, including the receptors on the sperm and egg, leading to the Ca2+ rise are not fully known. In the sea star, Patiria miniata, SFK1, SFK3, and PLCγ are known signaling molecules who are responsible for causing the internal Ca2+ rise from the endoplasmic reticulum. These three proteins share common features including signaling through SH2 domains and their activity is controlled by tyrosine phosphorylation. Using transcriptomics and phospho-proteomics to search for more molecules with these same …

Spatial Ecology And Stable Isotope Composition Of Cetaceans In The Bohol Sea, Edna Sabater

Theses and Dissertations

Studies on Philippine cetaceans (i.e., whales and dolphins) began in the early 1980s, and have resulted in the location and identification of species in Philippine waters. However, the population estimates of most of the cetacean species are uncertain, which is important in evaluating whether the populations are stable, decreasing, or increasing in relation to potential threats and conservation measures. I conducted line-transect surveys between 2010 and 2019 in the Bohol Sea, Philippines. A total of 2009.5 km survey efforts were made, which covered an area of 8041 km2 throughout the 5-year survey period. Distance sampling methods estimated the total abundance …

Late Quaternary Vegetation And Climate History From The Lake Junín Plateau, Jacob Daniel Schiferl

Theses and Dissertations

Whether the Andean ecosystem is resilient against future climate change remains unclear. A 2018 IPCC special report identified that warming more than 1.5ºC above pre-industrial temperatures by the year 2100 would be a major disrupter to natural systems, by causing more frequent extreme heatwaves, prolonged droughts, extreme precipitation events, and biome shifts. The tropical Andes will likely exceed this 1.5ºC threshold within the next century, threatening the diverse and endemic biota found in one of the world’s largest biodiversity hot spots. Yet few studies have examined the response of the Andean system through past interglacial periods when the temperatures were …

Active Targeting Of Her2-Positive Breast Cancer Cells With Rapamycin-Functionalized Gold Nanorods, Bryan Edgar White

Theses and Dissertations

Breast cancer is a significant cause of cancer-associated deaths, with over 13% of women in the U.S. estimated to develop invasive breast cancer in their lifetime. The human epidermal growth factor receptor (HER2/neu) is a growth-promoting protein that is overexpressed in 15-20% of breast cancers (HER2-positive breast cancer). HER2- positive breast cancer generally grows and spreads more quickly than other breast cancers but can be targeted therapeutically. Drug targeting methods have been developed to stop the growth and spread of cancer. These methods include using specific antibodies to target overexpressed cancer cell surface antigens and delivering drugs via nanoparticles. However, …

Shprehitë E Të Ushqyerit Te Nxënsit E Shkollave Fillore Në Komunën E Gjilanit, Esra Spahiu

Theses and Dissertations

Ushqyerja është një nga faktorët kryesorë që ndikon në shëndetin e një individi, sidomos gjatë moshës shkollore, me qëllim që fëmija të rritet e zhvillohet mirë dhe të sigurojë shëndet dhe jetëgjatësi më të mirë. Studimet tregojnë se në Kosovë, ashtu si në botë, po shfaqet kërcënimi i mbipeshës dhe obezitetit (sidomos në moshën shkollore) të cilat shpesh pasohen me sëmundje të shumta kronike si në moshë të re edhe në moshë adulte. Qëllimi: Është që fëmijët të jenë sa më të shëndetshëm, më këtë punim jemi munduar që tu ofrojmë sado pak njohuri rreth ushqyerjes së shëndetshme të fëmijëve …