Life Sciences Commons^™

Understanding The Impacts Of Current And Future Environmental Variation On Central African Amphibian Biodiversity, Courtney A. Miller

University of New Orleans Theses and Dissertations

Global climate change is projected to impact multiple levels of biodiversity by imposing strong selection pressures on existing populations, triggering shifts in species distributions, and reorganizing entire communities. The Lower Guineo-Congolian region in central Africa, a reservoir for amphibian diversity, is predicted to be severely affected by future climate change through rising temperatures and greater variability in rainfall. Geospatial modelling can be used to assess how environmental variation shapes patterns of biological variation – from the genomic to the community level – and use these associations to predict patterns of biological change across space and time. The overall goal of …

Genetic Diversity In An Invasive Clonal Plant? A Historical And Contemporary Perspective, Elliot D. Weidow

University of New Orleans Theses and Dissertations

Introduced populations of Eichhornia crassipes (Pontederiaceae) possess extremely low levels of genetic diversity due to severe bottleneck events and clonal reproduction. While populations elsewhere have been well studied, North American populations of E. crassipes remain understudied. We used Amplified Fragment Length Polymorphism markers to assess genetic diversity and population structure in North American E. crassipes populations. Patterns of diversity over the past fifty years were analyzed using herbarium specimens. Furthermore, we sampled populations across the Gulf Coast of the United States throughout a year to determine contemporary genetic diversity and assess potential seasonal effects. Genetic diversity was found to be …

Characterization Of Genes Involved In The Biosynthesis Of Phycoerythrin I And Ii In Cyanobacteria, Adam Nguyen

University of New Orleans Theses and Dissertations

Cyanobacteria are photosynthetic prokaryotes that able to produce oxygen. They have light harvesting complexes called phycobilisomes (PBS). PBS are generally composed of an allophycocyanin core with phycocyanin and phycoerythrin rods connected to the core. PBS are able to efficiently harvest light energy from different wavelengths of visible light due to the evolution of PBP. Phycoerythrin has five chromophores that are attached to six cysteine residues and is essential for efficient green light capture and transfer of energy for use in photosynthesis. The attachment of these chromophores to PBP is facilitated by enzymes known as bilin lyases.

In this study, we …

Zooplankton Community Composition In Natural And Artificial Estuarine Passes Of Lake Pontchartrain, Louisiana, Arnaud Kerisit

University of New Orleans Theses and Dissertations

I assessed the composition of zooplankton communities at the three tidal inlets connecting Lake Pontchartrain to Lake Borgne and subsequently to the Gulf of Mexico. The objectives of my research were to better understand the factors contributing to both spatial and temporal differences in zooplankton communities at the three locations. Monthly samplings of the neuston were conducted from September 2009 until April 2011 and then again from September 2012 until May 2013. Sampling consisted of triplicate tows using SeaGear “Bongo” nets. Water quality data along with water turbidity were recorded at each site and during each sampling effort. All specimens …

Analysis Of Temperature And Salinity Effects On Growth And Mortality Of Oysters (Crassostrea Virginica) In Louisiana, Troy Sehlinger

University of New Orleans Theses and Dissertations

Salinity (S) and temperature (T) control every facet of the eastern oyster (Crassostrea virginica) life cycle, principally reproduction, development, growth, and mortality. Previous studies conducted in in the Breton Sound (BR) and Barataria (BA) estuaries have reported differences in growth and mortality rates between the basins. In the present study, environmental conditions were synchronized to compare growth and mortality rates between basins at similar combinations of T and S. Results indicate that when T and S are the same (synchronized), seasonal oyster growth and mortality rates differ between BR and BA. Seasonal analyses revealed that as salinities increased …

The Effects Of Passive Integrated Transponder Tagging On Cortisol Release In The Gulf Killifish, Fundulus Grandis, Ariel Marcelo Hernandez

Senior Honors Theses

Due to its ease of use, low cost, and essentially limitless number of unique codes, PIT tagging has become the favored technique for tagging individuals in biological studies. However, studies employing PIT tagging generally assume that stress due to the implantation and presence of a PIT tag has no influence on the experimental results. This study investigated the effects of PIT tagging on levels of the stress hormone cortisol in the Gulf Killifish, Fundulus grandis, an estuarine fish of the Gulf of Mexico that is prone to daily or seasonal environmental stressors. Cortisol was measured non-invasively by extracting and …

Search For The Nuclear Localization Signal Of Ime4, Christian Monroy Hernandez

Senior Honors Theses

Ime4 is the catalytic subunit of a conserved methyltransferase (MTase) complex found in yeast, S. cerevisiae. This complex is responsible for creating the RNA modification N6- methyladenosine (m6A), the most common post-transcriptional modification in higher eukaryotes. There is evidence to suggest that m6A is an important mediator of gene expression control within the cell and has been associated with a diverse array of phenotypic effects, notably as a conserved determinant of cell fate. The MTase complex is known to be a nuclear protein, the compartment where it is believed to carry out most of its methylation activity. Recently, the nuclear …

Characterization Of Genes Involved In Chromatic Acclimation In The Cyanobacterium Synechococcus Sp. A 15-62, Suman Pokhrel

Senior Honors Theses

Synechococcus, a genus of photosynthetic cyanobacteria, is the second most abundant oxygenic microorganism in the marine environment that contributes significantly to the ocean’s primary productivity (Humily et al. 2013; Shukla et al. 2012). They are capable of utilizing available light of different wavelengths in the visible spectrum to perform photosynthesis and fix carbon dioxide and thus inhabit a wide range of light niches in the ocean along horizontal (coast vs offshore) and vertical gradients (depth) (Humily et al. 2013). A gene encoding a putative lyase isomerase, mpeQ, is present in phycoerythrin-II encoding operon that is expressed constitutively and …

Possible Breakdown Of Dopamine Receptor Synergism In A Mouse Model Of Huntington's Disease, Samantha F. Kennedy

University of New Orleans Theses and Dissertations

The model of basal ganglia function proposed by Albin, Young and Penney (1989) describes two anatomically independent motor pathways, the direct and indirect. However, under normal conditions striatal dopamine (DA) is required for the expression of motor behavior, and DAergic control of the two pathways (via D1 and D2 receptors, respectively) is dependent on co-activation. We tested for a possible breakdown of D1/D2 synergism using transgenic R6/1 mice bearing the human huntingtin allele (Htt). Motor stereotypy, observed prior to the onset of HD-related symptoms, was rated on a 5-point scale following activation of: A) D1 receptors alone, B) D2 receptors …

Exploring Science Identity: The Lived Experiences Of Underserved Students In A University Supplemental Science Program, Lynette D. Perrault

University of New Orleans Theses and Dissertations

Underserved students attending under-resourced schools experience limited opportunities to engage in advanced science. An exploration into the influence a supplemental science program has on underserved students’ acquisition of science knowledge and skills to increase their pursuit of science was conducted to help explain science identity formation in students. The proliferation of supplemental science programs have emerged as a result of limited exposure and resources in science for underserved students, thus prompting further investigation into the influence supplemental science programs have on underserved students interest and motivation in science, attainment of science knowledge and skills, and confidence in science to promote …

Conflict, Constraint, And The Evolution Of The Multivariate Performance Phenotype, Ann M. Cespedes Phd

University of New Orleans Theses and Dissertations

Performance is key to survival. From day-to-day foraging events, to reproductive activities, to life-or-death crises, how well an organism performs these tasks can determine success or failure. Selection, therefore, both natural and sexual, act upon performance, and performance demands on individuals shape a population’s morphological and physiological trait distributions. While studies of morphological adaptations to ecological pressures implicitly center on the idea that responses to selection improve performance via changes in morphology, the relationships between morphology, performance, and fitness are not always well understood. In this dissertation, I investigate these relationships explicitly, as well as determine the effects that different …

Wing Shape Variation In The Mimetic Butterfly Papilio Dardanus (Papilionidae) And Its Unpalatable Nymphalid Models, Miles Hegedus

University of New Orleans Theses and Dissertations

Papilio dardanus displays female-limited polymorphic mimicry of multiple model species. Butterfly wing shape is species-specific and can influence mimetic signaling, but has not been characterized in this species. We used elliptical fourier analysis to investigate whether mimetic P. dardanus female forms have converged on the wing shape of their respective models. Although both models and mimics varied in forewing and hind wing shape, we found no evidence of forewing shape convergence between them. Overall, forewings did not differ in shape between sexes in P. dardanus, nor in four non-mimetic Papilio used for comparison. Similarly, there were no hind wing …

Mechanisms Of Invasion And Competition In Anolis Sagrei And Anolis Carolinensis Lizards In Southeastern Louisiana, Jessica R. Edwards

University of New Orleans Theses and Dissertations

Invasive species can have a variety of effects on the behavior and ecology of native species. Currently in New Orleans, Louisiana, both A. sagrei and A. carolinensis lizards are relatively abundant, but the A. sagrei population is expanding rapidly. I used a combination of laboratory and field studies to investigate factors that might be influencing local dominance of invasive A. sagrei over native A. carolinensis populations, including habitat use, display behavior, interspecific aggressive interactions, and plasticity. When comparing display behavior and habitat use in anole populations across three field sites in southern Louisiana, I found differences in male display behavior …

Machine Learning Based Protein Sequence To (Un)Structure Mapping And Interaction Prediction, Sumaiya Iqbal

University of New Orleans Theses and Dissertations

Proteins are the fundamental macromolecules within a cell that carry out most of the biological functions. The computational study of protein structure and its functions, using machine learning and data analytics, is elemental in advancing the life-science research due to the fast-growing biological data and the extensive complexities involved in their analyses towards discovering meaningful insights. Mapping of protein’s primary sequence is not only limited to its structure, we extend that to its disordered component known as Intrinsically Disordered Proteins or Regions in proteins (IDPs/IDRs), and hence the involved dynamics, which help us explain complex interaction within a cell that …

Negative Regulation Of Haa1 By Casein Kinase I Protein Hrr25 In Saccharomyces Cerevisiae, Morgan Collins

University of New Orleans Theses and Dissertations

Haa1 is a transcription factor that adapts Saccharomyces cerevisiae cells to weak organic acid stresses by activating the expression of various genes. How Haa1 is activated by weak acids is not clear. This study proposes that Hrr25 is an important regulator of cellular adaptation to weak acid stress by inhibiting Haa1 through phosphorylation. YRO2, one of the targets of Haa1, shows increase in expression during stationary phase. This increase is due to basal activity of Haa1 and another, unknown, transcription factor. This study proposes that Gsm1 is another transcription factor that regulates YRO2 expression in the stationary phase. Finally, …

Size-Dependent Patterns Of Reproductive Investment In The North American Invasive Plant Species Triadica Sebifera (L.) Small (Euphorbiaceae), Courtney H. Babin

University of New Orleans Theses and Dissertations

Knowledge of sex allocation trade-offs with tree growth in insect-pollinated woody plants is limited, particularly in invasive plants. This study examined patterns of growth and reproductive investment in a North American invasive plant species, Triadica sebifera, I hypothesized that the energy limitations of smaller trees may result in the production of more male reproductive structures that are energetically less costly. Diameter at breast height was a significant predictor of seed and catkin mass and regression can describe these relationships across sites. Seed and catkin mass were positively correlated across sites. The relationship between the seed mass:catkin mass ratio and …

Characterization Of Genes Involved In Phycobiliprotein Biosynthesis In Fremyella Diplosiphon And Thermosynechococcus Elongatus, Christina M. Kronfel

University of New Orleans Theses and Dissertations

Cyanobacteria are photosynthetic organisms that efficiently capture light by utilizing the light-harvesting complexes called phycobilisomes. In many cyanobacteria, phycobilisomes are composed of an allophycocyanin core with phycocyanin and phycoerythrin (PE) rods radiating from the core. These phycobiliproteins have multiple bilin chromophores, such as phycoerythrobilin (PEB), covalently attached to specific cysteine (Cys) residues for efficient photosynthetic light capture. Chromophore ligation on phycobiliprotein subunits occurs through bilin lyase catalyzed reactions.

This study mainly focuses on characterizing the roles of enzymes that are involved in the biosynthetic pathway of the phycobiliproteins within two cyanobacteria Thermosynechococcus elongatus and Fremyella diplosiphon. A combination of molecular …

Role Of Ime4 And Pho92 Proteins In Pho5 Regulation, Krishna Shah

Senior Honors Theses

In the yeast Saccharomyces cerevisiae, m6A methylation regulates the stability and translation of mRNA. Ime4, which is highly active in meiotic cells, recognizes consensus methyl sites in pre-mRNA and adds methyl groups to a small fraction of adenosine residues, whereas Pho92 binds to such methylated sites and promotes subsequent degradation. PHO5 transcripts expression is upregulated when IME4 and PHO92 are deleted. In the PHO5 transcript, near the stop codon of the open reading frame (ORF), there is a potential consensus methyl site that is predicted to be methylated, based on its location and excellent match to the consensus methylation sequence …

Adaptation To Blue Light In Marine Synechococcus Requires Mpeu, An Enzyme With Similarity To Phycoerythrobilin Lyase Isomerases, Wendy M. Schluchter, Rania Mohamed Mahmoud, Joseph Sanfilippo, Adam A. Nguyen, Johann A. Strnat, Frédéric Partensky, Laurence Garczarek, Nabil Kassem, David M. Kehoe

Biological Sciences Faculty Publications

Marine Synechococcus has successfully adapted to environments with different light colors, which likely contributes to this genus being the second most abundant group of microorganisms worldwide. Populations of Synechococcus that grow in deep, blue ocean waters contain large amounts of the blue-light absorbing chromophore phycourobilin (PUB) in their light harvesting complexes (phycobilisomes). Here, we show that all Synechococcus strains adapted to blue light possess a gene called mpeU. MpeU is structurally similar to phycobilin lyases, enzymes that ligate chromophores to phycobiliproteins. Interruption of mpeU caused a reduction in PUB content, impaired phycobilisome assembly and reduced growth rate more strongly in …

Territoriality And Spatial Structure In The Green Anole, Anolis Carolinensis, William D. Weber Jr.

University of New Orleans Theses and Dissertations

Anolis carolinensis has been a model organism for ecology and evolutionary biology since the seventies, yet there are still understudied aspects of their ecology. A five-year study has provided microsatellite genotypes to be used in building a pedigree and assess relatedness, enabling us to evaluate the spatial distribution of an urban population of A. carolinensis. Results indicate no correlation between a male’s size and the distance others keep from it; however, males belonging in the heavyweight morph are dictating the spatial distribution in this population. In addition, juvenile dispersal of male offspring and partial philopatry of female offspring are …

Understanding The Historical Diversification Of Valerianacea, Taylor Lebourgeois

Senior Honors Theses

Ecologists and evolutionary biologists have long recognized that species diversity is unequally distributed among angiosperm lineages. For example, various plant clades found in the Andes have been proposed as examples of rapid radiations, and the Andes are recognized as one of the Earth’s biodiversity “hotspots”. Species within Valerianaceae, found in the South American Andes, appear to be an example of such a rapid radiation. Although much attention has been paid to the phylogeny of the South American species of Valerianaceae, there is still a great deal of uncertainty regarding species relationships. Several subgroups within the Andean Valerians have, either not …

Habitat Suitability Modeling For The Mississippi Sandhill Crane, Grus Canadensis Pulla, Linda C. Salande

University of New Orleans Theses and Dissertations

In this study, I modeled the suitability of habitat on the Mississippi Sandhill Crane National Wildlife Refuge for the federally endangered Mississippi Sandhill Crane (Grus Canadensis pulla). Habitat type and suitability changed over time due to seasonality of vegetation and succession in the absence of burning. Cranes used highly suitable habitat more in the non-growing than in the growing season, and may have been more constrained by resource availability during winter months. Cranes used some less-suitable areas including cypress drains, which provide roosting sites, and supplemental food plots. The mismatch between predicted quality and crane use suggests that …

Comparing Methods Of Euthanasia And Gill Culture For Hypoxia Research On The Gulf Killifish, Fundulus Grandis, Kristina M. Farragut

University of New Orleans Theses and Dissertations

Aquatic hypoxia, or low dissolved oxygen, is a growing environmental concern and has detrimental effects on many fishes. Research on fish responses to hypoxia includes whole animal studies as well as organ culture systems. In this thesis, the gulf killifish, Fundulus grandis, was used to determine the interaction between hypoxic exposure and four common euthanasia techniques on selected blood and gill variables and to develop an in vitro gill incubation system. Euthanasia techniques had differential effects on blood and gill, with the common fish anesthetic MS-222 having the greatest effects, but none altered the response to hypoxia. During the …

Phylogenetic Relationships And Evolution Of Snakes, Alex Figueroa

University of New Orleans Theses and Dissertations

Snakes represent an impressive evolutionary radiation of over 3,500 widely-distributed species, categorized into 515 genera, encompassing a diverse range of morphologies and ecologies. This diversity is likely attributable to their distinctive morphology, which has allowed them to populate a wide range of habitat types within most major ecosystems. In my first chapter, I provide the largest-yet estimate of the snake tree of life using maximum likelihood on a supermatrix of 1745 taxa (1652 snake species + 7 outgroup taxa) and 9,523 base pairs from 10 loci (5 nuclear, 5 mitochondrial), including previously unsequenced genera (2) and species (61). I then …

The Origin And Expansion Of The Eastern Red Fox, Adrienne Egge Kasprowicz

University of New Orleans Theses and Dissertations

When new populations are first identified in a region there are multiple potential sources: introduction of a non-native species, extra-range expansion of a nearby population, or demographic growth of a previously unnoticed species. Red foxes were absent or rare in the mid-eastern portion United States until the late 1800s. Their origins potentially include natural population increase/expansion, translocations from Europe, and, eventually, 20th century fur farming. In this study I attempt to identify the relative impact of native expansion versus human mediated introductions of both colonial era European foxes and early 20^th century fur-farm foxes on the establishment of red …

Purification And Characterization Of Antibodies Against Killifish Hif-1Α, Janet Gonzalez-Rosario

University of New Orleans Theses and Dissertations

Many fish face low oxygen concentrations (hypoxia) in their natural environments, and they respond to hypoxia through a variety of behavioral, physiological, and cellular mechanisms. Some of these responses involve changes in gene expression. In mammals, the hypoxia inducible factor (HIF) family of transcription factors are the “master regulators” of gene expression during hypoxia, but the study of HIF in fish has been hampered by the lack of reagents to detect this protein in non-mammalian vertebrates. The goals of this thesis are to affinity purify antibodies against HIF from the killifish Fundulus heteroclitus and use them to recover and quantify …

The Effects Of Forest Age And Management On Bee Communities Of Production Forests In The Southern United States, Robinson Sudan

University of New Orleans Theses and Dissertations

Processes structuring bee communities in agricultural landscapes are well-documented compared to those in other anthropogenic landscapes, like production forests. Forests across the temperate zone have historically been under-sampled, in part due to the perception that they provide little habitat to support diverse bee communities. While research suggests that early successional habitats support high levels of bee species richness and abundance, little empirical evidence exists to support the notion that forests, in turn, do not. To understand the relationship between forest successional age and major elements of the bee community, I sampled bees in a southern production pine forest in Hancock …

Determining The Pollination Mechanism Of A Problematic Invasive Species In The Gulf South: Triadica Sebifera, Jennifer Wester Clark

University of New Orleans Theses and Dissertations

Understanding the ecology of invasive species is vital to curb the homogenizing of ecosystems, yet the pollination mechanisms of the Chinese tallow tree (Triadica sebifera) in its introduced habitat remain ambiguous. This study examines self-pollination, wind pollination, and flower-visiting insects of tallow in a bottomland hardwood forest and Longleaf pine savannah in the U.S. Gulf South. These data suggest that self-pollination and airborne pollination are possible, but likely rare occurrences, although the possibility of apoxisis was not investigated. Seed production in exclusion experiments was significantly less than in open-pollinated flowers, and wind dispersal of tallow pollen dropped to …

Working Memory Impairments In Chromosome 22q11.2 Deletion Syndrome: The Roles Of Anxiety And Stress Physiology, Ashley F. P. Sanders

University of New Orleans Theses and Dissertations

Stress and anxiety negatively impact the working memory system by competing for executive resources. Broad memory deficits have been reported in individuals with chromosome 22q11.2 deletion syndrome (22q11.2DS). We investigated anxiety and physiological stress reactivity in relation to visuospatial working memory impairments in 20 children with 22q11.2DS and 32 typically developing children (M = 11.10 years, SD = 2.95). Results indicate reduced post-stress RSA recovery and overall increased levels of cortisol in children with 22q11.2DS. Additionally, anxiety mediated the relationship between 22q11.2DS and visuospatial working memory impairment. However, there was no indication that stress response physiology mediated this association. …

An Alternate Trawling Method: Reduced Bycatch And Benthic Disturbance Achieved With The Wing Trawling System, Geoffrey Udoff

University of New Orleans Theses and Dissertations

The Wing Trawling System (WTS) was tested as an alternative to traditional shrimp capture methods in the Gulf. Compared to an otter trawl, this trawl was conceived to reduce bycatch, retain shrimp catch, and minimize seafloor disturbance. Through seventy-one paired tows, the WTS was assessed against a standard otter trawl. The WTS was found to reduce bycatch by 63-65% and reduce shrimp catch by 30-35%. Additionally, I measured the depth of the scars produced by both trawls and quantified the turbidity of the plumes behind them. The scars left by the WTS and the otter trawl were between 9.9 …