Life Sciences Commons^™

Severe Hypoxia Up-Regulates Gluconeogenesis In Daphnia, Morad C. Malek

Undergraduate Honors Theses

Hypoxia is a significant low oxygen state that has complex and diverse impacts on organisms. In aerobes, various adaptive responses to hypoxia are observed that vary depending on the level of oxygen depletion and previous adaptation, hence the continued attention to hypoxia as an important abiotic stressor. Adaptive responses to hypoxia are primarily governed by the hypoxia-inducible factors (HIFs), which activate downstream genetic pathways responsible for oxygen transport and metabolic plasticity. In aquatic habitats, oxygen availability can vary greatly over time and space. Therefore, aquatic organisms’ adaptation to hypoxia is likely pervasive, especially in genotypes originating from waterbodies prone to …

Analysis Of Edna To Assess Effects Of Water Quality On Freshwater Fungal Diversity In A Virginia Coastal Watershed, Lauren French

Undergraduate Honors Theses

Freshwater fungi comprise a phylogenetically and functionally diverse group which contributes to wide-ranging ecosystem processes in aquatic systems. Saprotrophic fungi convert detritus into nutrient-rich food sources for fish and invertebrates, whereas pathogenic and parasitic fungi can cause disease and population declines of other aquatic organisms. With their diverse and important roles, changes in freshwater fungal community structure may have far-reaching impacts on ecosystems. To understand how natural and anthropogenic stressors to freshwater systems impact fungal-mediated ecosystem processes, a greater understanding of the taxonomic and functional composition of freshwater fungal communities is needed. We assessed relationships among freshwater habitat types, water …

Welcoming The Game Changer Of Human Society: A Defense Of The Moral Permissibility And Obligations Of Human Genetic Engineering, Yongkang Li

Undergraduate Honors Theses

In 2018, a Chinese scientist, Jiankun He, announced the birth of two HIV-resistant babies through his experiment of human genetic engineering. This incidence has soon shocked the entire scientific community and invoked public outrage towards He’s corrupt moral integrity.

However, this event should also act as a harbinger to the human society that the technique of human genetic engineering is rapidly approaching maturity. In that case, how should we respond?

This thesis focuses on the moral issues surrounding human genetic engineering and advertises an accepting moral attitude to this booming technology. This thesis will first discuss the types of human …

Sleep Modifications In A Drosophila Melanogaster Model Of Fragile X Syndrome, Morgan Mclaughlin

Undergraduate Honors Theses

Fragile X syndrome (FXS) is a neurodevelopmental disorder characterized by intellectual disabilities, disruptions in sleep, and autism in humans. Mutations in Fragile X Mental Retardation gene 1 (FMR1), which codes for a protein that modifies the expression of many target proteins, are primarily responsible for this disorder. Genetic modifications of FMR1 can increase or decrease the overall amount of sleep in humans. A potential pharmaceutical target of FXS is dopamine, a critical neurotransmitter in the regulation of sleep and wakefulness. In fruit flies (Drosophila melanogaster) dopamine has been shown to alter sleep. The mushroom body, a structure in …

Modeling Hybrid Novel Traits: A Case Study In Complex Petal Pigment Patterning In Hybrid Mimulus, Xingyu Zheng

Undergraduate Honors Theses

Hybridization between species, by introducing dramatic trait variation into the population and creating viable, transgressive offsprings with novel phenotypes, can have huge evolutionary implications. Some hybrid traits have been studied in the classical genetics or population genetics context, but most complex traits are determined by multiple causes, e.g. the number of loci involved, the rewiring of the genetic circuitries, and the changes in gene expression pattern. Using the hybrid monkeyflower petal pigment patterning as an example, we present a case study to investigate complex hybrid traits in a systematic manner that includes empirical data analysis and quantitative mathematical modeling of …

Characterization Of The Broad-Spectrum Inhibitory Capability Of Alcaligenes Faecalis And A. Viscolactis Against Potential Pathogenic Microorganisms, Andrew Fuqua

Undergraduate Honors Theses

The recent rise of multidrug resistant microorganisms has grown from an isolated concern to a massive public health crisis. It has become imperative that scientists look for new ways to combat this issue. Due to the selective pressures of competition, bacteria and other microbes possess a host of defenses and weapons designed to exploit vulnerabilities in other microorganisms. Consequently, the study of these systems and microbial interactions has much to reveal in the search for novel antimicrobial treatments. Previous research from our laboratory has discovered that both Alcaligenes faecalis and Alcaligenes viscolactis, two rarely studied and generally non-virulent bacteria, …

Subcellular Localization Of Tobacco Sabp2 Under Normal And Stress Conditions, Sanjeev Das

Undergraduate Honors Theses

Subcellular Localization of Tobacco SABP2 under Normal and Stress Conditions

Salicylic acid (SA), a phytohormone, plays an important role in plant physiology. SA mediated innate immune pathway is an important pathway for plant immunity against pathogens. Plants resisting pathogen infection synthesize higher levels of Methyl Salicylate (MeSA), which is then converted to SA by the esterase activity of Salicylic Acid Binding Protein 2 (SABP2). The high level of the converted SA leads to enhanced pathogen resistance. The study of subcellular localization of a protein is critical in explaining its potential biochemical functions. SABP2 tagged with eGFP was expressed transiently in …

Analysis Of Genetic Structure And Pathogen Dynamics Of Ixodes Scapularis In Southwestern Virginia, Leemu Jackson

Undergraduate Honors Theses

Ixodes scapularis, or the blacklegged tick, is the primary vector of Borrelia burgdorferi. This pathogen is the causative agent of Lyme disease, the most common vector-transmitted disease in the United States. Although I. scapularis is distributed throughout the eastern U.S., Lyme disease is only considered endemic in the northeastern region of the country. Prior to 2007, Lyme disease was uncommon in Virginia, but since then cases of Lyme disease have increased dramatically with a hotspot forming in the Roanoke-Blacksburg area. The purpose of the current study was to determine whether B. burgdorferi prevalence and the genetic structure of I. …

Identification Of Genes Involved In Iron Metabolism In Rhizobium Leguminosarum Atcc 14479 Genome Through The Use Of In-Silico Analysis, Shuaib A. Siddiqui

Undergraduate Honors Theses

The complete genomic sequence of Rhizobium leguminosarum ATCC 14479 has been determined. Its genome size is 7,935,223 base-pairs of DNA (bp). This multipartite genome contains 5 distinct replicons: a chromosome of 4,883,137 bp and four mega-plasmids of size 1,234,209 bp, 415,988 bp, 771,583 bp, and 630,306 bp. In silico (literally: on computer) analysis was done on the complete genome to detect genes relating to iron metabolism by bacteria. Seven iron-related operons and genes were found: nodulation genes, the Tol operon, the hmuPSTUV operon, iron response regulator genes, the cycHJKL operon, genes for bacterial cyclic glucans, and vicibactin genes.

Examining The Neuronal Dopaminergic Pathway Underlying Sleep Behavior And Related Dopamine Sleep Disorders, Mary Beth Putz

Undergraduate Honors Theses

The human brain is an extremely complex organ with approximately 100 billion different neurons that are constantly sending and receiving messages. These messages are sent using the chemical messengers of the brain: neurotransmitters and neuromodulators. Mechanisms of neural control of sleep are substantially conserved across species. Evidence from multiple animal models including flies, zebrafish, and mice shows that the arousal, or wake phase, is regulated by conserved neuromodulators such as dopamine, norepinephrine, and serotonin. Since these neurotransmitter systems are distributed throughout the brain and sub-serve many functions in addition to sleep, the precise circuit mechanisms by which these neurotransmitters regulate …

Changes In Synaptic Protein Content And Signaling In A Mouse Model Of Fragile X Syndrome, Kelly Birch, Peter W. Vanderklish Phd

Undergraduate Honors Theses

Fragile X Syndrome--the most common inherited form of intellectual disability--is characterized by low IQ, impaired social interaction, hyperactivity and impulsivity, and abnormal physical traits including an elongated face and protruding ears. Nearly half of all children with Fragile X also meet diagnostic criteria for autism spectrum disorder. Fragile X is caused by a trinucleotide repeat expansion on the X chromosome, leading to silencing of the Fragile X mental retardation gene (FMR1) and thus lack of expression of Fragile X mental retardation protein (FMRP). As a key translational suppressor, FMRP is crucial for normal neural development and synaptic function. The current …

Phylogenetic Analysis Of Human Cytomegalovirus Pus27 And Pus28: Ascertaining An Independent Or Linked Evolutionary History, Jessica A. Scarborough

Undergraduate Honors Theses

Human cytomegalovirus (HCMV) is a widespread pathogen that is particularly skilled at evading immune detection and defense mechanisms, largely due to extensive co-evolution with its host’s immune system. One aspect of this co-evolution involves the acquisition of four virally encoded GPCR chemokine receptor homologs, products of the US27, US28, UL33 and UL78 genes. G protein-coupled receptors (GPCR) are the largest family of cell surface proteins, found in organisms from yeast to humans. In this research, phylogenetic analysis was used to investigate the origins of the US27 and US28 genes, which are adjacent in the viral genome. The results indicate that …

Tropical Trees As Islands: Diversity Accumulation Of Armored Scale Insects (Hemiptera: Diaspididae) On Trees As A Function Of Forest Age, Hannah Shapiro

Undergraduate Honors Theses

Armored scale insects (Hemiptera: Diaspididae) are some of the most invasive insects in the world. These cryptic plant parasites are most often encountered in managed agricultural ecosystems, but very little is known about their distribution, abundance, and diversity in tropical rainforest canopies, where they are likely to have their highest diversity. Because these ubiquitous insects are extreme generalists with undirected dispersal, their diversity (alpha and beta) accumulation can conceivably be modeled according to tenets derived from island biogeography theory. For example, one expectation is that older established trees should boast a higher species diversity and abundance than younger ones. Other …

The Effects Of Sustained, High-Velocity Exercise On Gene Expression In California Yellowtail (Seriola Lalandi), Kelli Hatter

Undergraduate Honors Theses

California Yellowtail muscle fibers have been observed to exhibit two drastically different development patterns resulting from the speeds at which they are exercised. When fish are exercised at a moderate rate their epaxial fast-twitch muscle fibers grow in diameter—hypertrophy; when they are exercised at a fast speed, more new epaxial fast-twitch muscle fibers are produced—hyperplasia. To determine the underlying reason for this difference in muscle development, my summer research project and honors thesis exercised fish at: fast, moderate, and control speeds for a sustained amount of time to determine what is happening on a cellular level to cause the observed …

Distribution And Identification Of Fish Eggs In An Internal Wave Transport Mechanism, Claire Kuelbs

Undergraduate Honors Theses

Internal waves have been proven to transport invertebrate larvae onshore, but there has been little indication on whether internal waves transport fish eggs. Fish eggs are typically buoyant and are often found in neustonic samples, and internal waves often cause fronts that transport oils and other light particles. This research aims to determine whether there are patterns to the distribution of fish eggs. One possibility is that offshore fish eggs can be transported onshore, to nearshore nursery habitats. Before 2003, when genetic barcoding was proposed as an identification mechanism, fish eggs could only be identified visually, using color, size, and …