Life Sciences Commons^™

Role Of Msaa Gene In Regulation Of The Msaabcr Operon And Biofilm Development In Staphylococcus Aureus, Ahmed Alzuway

Master's Theses

Staphylococcus aureus is an important human pathogen that causes wide variety of diseases ranging from chronic biofilm associated infection to acute life threatening infection such as bacteremia, pneumonia, osteomyelitis, or endocarditis, despite the progress with antibiotics used in the treatment of bacterial infections. Furthermore, increased use of prosthetic and indwelling devices in modern medical practices has led to increased infections due to S. aureus. Treating S. aureus infections have become difficult owing to its ability to resist most of the antibiotics; this problem is further exacerbated by ability of MRSA strains to form biofilms. Emergence of community-acquired methicillin resistance …

Effects Of Water Parameters On Container Mosquito (Diptera: Culicidae) Oviposition And Performance, Stephanie Sue Schelble

Master's Theses

Water body parameters have a considerable effect on the communities that develop within them. In small container habitats like tires, the depth, surface area, and volume effect the development and success of the mosquito communities. This study investigated the choices of the adult female mosquitoes, Aedes albopictus and Culex quinquefasciatus, between different depths and surface areas. In addition, larval performance was determined under differing depth and larvae densities. Oviposition studies showed that Ae. albopictus had a preference for deeper habitats (χ²= 14.2902, p= 0.0139) but did not prefer any surface areas (χ²= 7.2321, p= 0.0649) though …

Effects Of Animal Management Changes On The Activity Budgets And Walking Rates Of Zoo Elephants, Angela Dawn Mackey

Dissertations

The current study aimed to assess the effects of two management strategies, weekly rototilling of the enclosure and the provision of unpredictable foraging opportunities, on the daily behavior of six elephants housed at the San Diego Zoo. Observations took place from January to June 2013 and were conducted throughout a 24- hour period. The study was divided into three phases, each two months in duration. During the first phase (baseline) no changes were made to the current management routine of the elephants. In Phase 2, rototilling of the elephant enclosures was increased from once monthly to once per week, while …

Self-Assembled Gold Nanoplexes For Cancer-Targeted Sirna Delivery, Yongliang Shi

Master's Theses

Through layer-by-layer method, the authors have constructed three Au nanoplexes: AuPEI/RNA/PEI, AuPEI/RNA/PEI-mPEG, and AuPEI/NA/PEI-PEG-FA. All the nanoplexes are characterized by UV-vis spectrometry, DLS, and zeta potential. The surface density of the first layer PEI and second layer RNA were also determined. Moreover, the Au nanoplexes can protect siRNA from RNase degradation and are stable in cell culture medium.

siGLuc-ppp, ssRNA₈₀, and siF17 were delivered by the assembled Au nanoplexes, and the results were analyzed by GLuc assay, TB assay, and Luciferase assay. In terms of RNA delivery, the Au nanoplexes AuPEI/RNA/PEI exhibited excellent gene silencing efficiency (or causing …

Gelatinous Zooplankton Biomass In The Global Oceans: Geographic Variation And Environmental Drivers, Cathy H. Lucas, Daniel O.B. Jones, Catherine J. Hollyhead, Robert H. Condon, Carlos M. Duarte, William M. Graham, Kelly L. Robinson, Kylie A. Pitt, Mark Schildhauer, Jim Regetz

Faculty Publications

Aim

Scientific debate regarding the future trends, and subsequent ecological, biogeochemical and societal impacts, of gelatinous zooplankton (GZ) in a changing ocean is hampered by lack of a global baseline and an understanding of the causes of biogeographic patterns. We address this by using a new global database of GZ records to test hypotheses relating to environmental drivers of biogeographic variation in the multidecadal baseline of epipelagic GZ biomass in the world's oceans.

Location

Global oceans.

Methods

Over 476,000 global GZ data and metadata items were assembled from a variety of published and unpublished sources. From this, a total of …

Identification And Characterization Of An Operon, Msaabcr, That Controls Virulence And Biofilm Development In Staphlococcus Aureus, Gyan S. Sahukhal, Mohamed O. Elasri

Faculty Publications

Background

Community-acquired, methicillin-resistant Staphylococcus aureus strains often cause localized infections in immunocompromised hosts, but some strains show enhanced virulence leading to severe infections even among healthy individuals with no predisposing risk factors. The genetic basis for this enhanced virulence has yet to be determined. S. aureus possesses a wide variety of virulence factors, the expression of which is carefully coordinated by a variety of regulators. Several virulence regulators have been well characterized, but others have yet to be thoroughly investigated. Previously, we identified the msa gene as a regulator of several virulence genes, biofilm development, and antibiotic resistance. We also …

Large Scale Screening Of Digeneans For Neorickettsia Endosymbionts Using Real-Time Pcr Reveals New Neorickettsia Genotypes, Host Associations And Geographic Records, Stephen Greiman, Vasyl V. Tkach, Eric Pulis, Thomas J. Fayton, Stephen S. Curran

Faculty Publications

Digeneans are endoparasitic flatworms with complex life cycles including one or two intermediate hosts (first of which is always a mollusk) and a vertebrate definitive host. Digeneans may harbor intracellular endosymbiotic bacteria belonging to the genus Neorickettsia (order Rickettsiales, family Anaplasmataceae). Some Neorickettsia are able to invade cells of the digenean's vertebrate host and are known to cause diseases of wildlife and humans. In this study we report the results of screening 771 digenean samples for Neorickettsia collected from various vertebrates in terrestrial, freshwater, brackish, and marine habitats in the United States, China and Australia. Neorickettsia were detected using a …

Interspecific Variation In Juvenile Snapper Otolith Chemical Signatures In The Northern Gulf Of Mexico, William F. Patterson Iii, Beverly K. Barnett, Michelle Zapp Sluis, James Howan Cowan Jr., Alan M. Shiller

Faculty Publications

The objective of this study was to evaluate whether age-0 lane snapper Lutjanus synagris otolith chemical signatures could serve as accurate proxies for those of its congener, red snapper L. campechanus, among northern Gulf of Mexico (GOM) nursery regions. Red (n = 90) and lane (n = 53) snappers were sampled from 3 regions of the northern GOM in fall 2005, and their otolith chemistry was analyzed with sector field-inductively coupled plasma-mass spectrometry (Ba:Ca, Mg:Ca, Mn:Ca, Sr:Ca, Li:Ca) or stable isotope ratio-mass spectrometry (δ¹³C and δ¹⁸O). Chemical signatures were significantly different among regions (MANOVA, p < 0.001) and between species (MANOVA, p = 0.029), with the species effect being driven by significant differences in 4 of the 7 constituents analyzed (ANOVA, p < 0.036). The significant region effect persisted (MANOVA, p < 0.001), but the species effect was non-significant (MANOVA, p = 0.964) when constituent values were normalized to species-specific means. Mean regional classification accuracies from linear discriminant functions computed with otolith constituent data were 84% for lane snapper and 80% for red snapper whether data were normalized or not. Maximum likelihood models parameterized with normalized lane snapper otolith chemistry data estimated red snapper regional composition reasonably well among mixed-region samples (mean error = 9.7% among models). Therefore, it appears age-0 lane snapper otolith chemical signatures can serve as accurate proxies for those of red snapper in the northern GOM. These results have broader implications for deriving natural tags based on otolith chemistry for fishes that may have low abundance in parts of their range.

Contribution Of Surface Leaf-Litter Breakdown And Forest Composition To Benthic Oxygen Demand And Ecosystem Respiration In A South Georgia Blackwater River, Andrew S. Mehring, Kevin A. Kuehn, Cynthia J. Tant, Catherine M. Pringle, R. Richard Lowrance, George Vellidis

Faculty Publications

Many North American blackwater rivers exhibit low dissolved O₂ (DO) that may be the result of benthic respiration. We examined how tree species affected O₂ demand via the quantity and quality of litter produced. In addition, we compared areal estimates of surface leaf-litter microbial respiration to sediment O₂ demand (SOD) and ecosystem respiration (ER) in stream and swamp reaches of a blackwater river to quantify contributions of surface litter decomposition to O₂ demand. Litter inputs averaged 917 and 678 g m⁻² y⁻¹ in the swamp and stream, respectively. Tree species differentially affected O_{2 …}

El Niño-Southern Oscillation Is Linked To Decreased Energetic Condition In Long-Distance Migrants, Kristina Paxton, Emily B. Cohen, Zoltán Németh, Frank R. Moore

Faculty Publications

Predicting how migratory animals respond to changing climatic conditions requires knowledge of how climatic events affect each phase of the annual cycle and how those effects carry-over to subsequent phases. We utilized a 17-year migration dataset to examine how El Niño-Southern Oscillation climatic events in geographically different regions of the Western hemisphere carry-over to impact the stopover biology of several intercontinental migratory bird species. We found that migratory birds that over-wintered in South America experienced significantly drier environments during El Niño years, as reflected by reduced Normalized Difference Vegetation Index (NDVI) values, and arrived at stopover sites in reduced energetic …

Revision Of 13 Genera Of Haploporidae (Trematoda), Eric Edward Pulis

Dissertations

The Haploporidae is a family of digeneans united by the combination of the possession of a hermaphroditic sac and a single testis or, rarely, two tandem testes. The major divisions in the Haploporidae have been based on the organization, development, and nature of the male and female reproductive systems. Overstreet and Curran (2005) has been the only attempt to organize the genera of the Haploporidae in a subfamilial framework. In the present work the validity of the subfamily Waretrematinae by Overstreet and Curran (2005) is assessed by morphological and molecular methods, based on original descriptions, type and vouchered, specimens and …

The Use Of A Small Molecule To Improve The Thermostability Of Dna Junctions, Arik Shams

Honors Theses

The short-term goal of this research project is to employ small molecules as a means to stabilize four-way DNA junctions (4WJs) composed of natural DNA and chimeric nucleic acids. The long-term goal of the project is utilizing the 4WJs as extracellular therapeutic inhibitors of DNA binding proteins [i.e. Histones and High Mobility Group Protein B (HMGB1b)]. A number of studies have shown that classical intracellular DNA-binding proteins have a variety of deleterious side-effects when present in the extracellular milieu. In order to develop a successful 4WJ therapeutic, we are focused on using modified nucleic acids to enhance the stability of …

Subcloning And Expression Of Complexin Isoforms Involved In Mast Cell Degranulation, Cameron Blake King

Honors Theses

Mast cells play an important role in the immune system by releasing chemicals such as chemokines and cytokines once they are stimulated. These products are released after stimulation by a process called mast cell degranulation. Mast cell degranulation is accomplished when vesicles containing the chemicals inside the mast cell fuse with the mast cell membrane via SNARE-mediated (Soluble NSF Attachment Protein Receptors) membrane fusion. This family of proteins consists of syntaxin, SNAP 25-like protein, and synaptobrevin/VAMP (Vesicle Associated Membrane Protein)(2). Comlexin isoforms (complexin 1,2,3,and 4) have been known to regulate this system in a fashion that is still unclear. In …

Investigating The Co-Regulatory Role Of Midline And Extramacrochaetae In Regulating Eye Development And Vision In Drosophila Melanogaster, Lillian M. Forstall

Honors Theses

The Honors thesis research focused on the roles of extramacrochaetae and midline in regulating eye development and the vision of Drosophila melanogaster. It is known from previous studies that extramacrochaetae (emc) and midline (mid) independently regulate the formation of ommatidial units in the Drosophila compound eye. However, the thesis focuses on the interaction of these two genes and their co-dependent roles in regulating eye development. This study also attempts to explain the recovered formation of ommatidial units and interommatidial bristles when the expression of both of these genes is reduced and whether flies doubly mutant …

Self Myofascial Release: Effects On Hamstring Range Of Motion And Torque, Dillion F. Evans

Honors Theses

Research has indicated that static stretching may reduce force production capabilities. This has led many practitioners to exchange static stretching for alternative methods of increasing range of motion (ROM) in warm-ups. Despite having little research to support its use, self myofascial release—foam rolling—has been suggested as a viable alternative (Macdonald et al, 2013). The objective of this study was to determine how self myofascial release (SMR) of the hamstring muscle group affects ROM and torque production capabilities of the hamstring muscle group. Ten subjects (age 26.5 6.5 years, mass 74.412.1 kg, height 1738 cm) were recruited. A within subjects randomized, …

Differences In Consumption Rates Between Juvenile And Adult Laccophilus Fasciatus Rufus (Coleoptera: Dytiscidae) On Larval Culex Quinquefasciatus (Diptera: Culicidae), Carmen E. Bofill

Honors Theses

With the increase of global temperature and human populations, prevalence of vector-borne diseases is becoming an issue for public health. Over the years these vectors have been notorious for developing resistance to human regulated insecticides. Thus, other forms of control, including the use of natural predators, have become an important topic in research. Research on member of the family of predaceous diving beetles (Dytiscidae) and their predatory ability to decrease aquatic mosquito larvae populations has been of recent interest. The purpose of this study is to 1) quantify consumption rates of the dytiscid Laccophilus fasciatus rufus juvenile and adults on …

Restoring The Longleaf Pine (Pinus Palustris) Forests Using Pineywoods Cattle Grazing In Conjunction With Prescribed Burning, L. Tyler Albin

Honors Theses

The longleaf pine (Pinus palustris) is major forest constituent of the Southern Coastal Plains of the United States. Ecologically, a virgin longleaf pine forests supports increased species richness. Since the 1800s, longleaf pine forests have been exploited as a massive source of commercial products (e.g., lumber, pulp, and naval stores). A decrease in species richness has been recorded following this vast decrease in longleaf pine presence. Rebuilding the longleaf pine ecosystem is essential for restoring species richness and maintaining the ecological health of many Costal Plains habitats. Presently, the most popular restoration and management method utilized is prescribed burning. Prescribed …

Regulation Of Gene Expression In Karenia Brevis, Skylar C. Rodgers

Honors Theses

Karenia brevis is species of dinoflagellate responsible for most of the harmful algal blooms that occur in the Gulf of Mexico. These blooms can be detrimental to the environment and the economy of a coastal region due to the brevetoxins produced by Karenia brevis. Currently, the cause of these blooms, as well as the mechanisms of associated toxin production, are unknown. Efforts to characterize Karenia brevis at a molecular level are ongoing. However, based on genomic findings, researchers have hypothesized that regulation of gene expression occurs post-transcriptionally. In many organisms, non-coding RNAs, such as natural antisense transcripts (NATs), play …

Resident Benthic Fishes Of Artificial Reefs In The Mississippi Sound: Effects Of Habitat Relief And Subregion, Claire Louise Matten

Master's Theses

One of the fundamental questions of artificial reef research concerns the capability of these manmade structures to promote secondary production. Many researchers have questioned whether artificial reefs increase the production of fish biomass, or simply aggregate existing fish biomass. Most previous research has focused on production of transient fish biomass, because of the high recreational and commercial value of these species. Establishing a link between transient fish production and artificial reef primary and secondary production has proved difficult. Therefore, the goal of this study was to examine the productivity of benthic fishes resident to artificial reefs in the Mississippi Sound, …

Taxonomy, Diversity, And Distribution Patterns Of Portunid Crab Megalopae In The Northern Gulf Of Mexico During Fall Of 2003, Carley Rain Knight

Master's Theses

The field of zooplankton biology contributes to more accurate stock assessments as well as to a greater understanding of the marine food web. However, adequate information for the invertebrate component of zooplankton is lacking compared to the ichthyoplankton component. In this thesis, identification of Portunidae (Crustacea: Decapoda) megalopae collected during the fall of 2003 from a NOAA SEAMAP cruise revealed 7 species and 11 morphs with 90% of the total density comprised of Callinectes sapidus, Achelous gibbesii, Callinectes similis, Achelous spinicarpus, and Achelous sp.I. Keys and detailed descriptions are provided along with photographs and morphological drawings for each morph to …

Choice And Control Of Enrichment For A Rescued And Rehabilitated Atlantic Bottlenose Dolphin (Tursiops Trunactus), Hannah Bahe

Honors Theses

Animals living under human care experience stress related to a lack of control over t environment. One way to remedy this is through the use of cognitive enrichment, su choice and control of enrichment. This type of enrichment has been shown to have benefits for animals under human care including increased activity and social interactions. To determine if choice and control was more beneficial than enrichmen alone, a three year old male Atlantic bottlenose dolphin (Tursiops truncatus) was ex to novel enrichment items in two experimental conditions. For the first condition, th animal was given a novel object. During the …

Three-Dimensional Reconstruction Of Marine Clay Nano- And Microstructure By Transmission Electron Microscopy: Analysis Of Fabric And Pore Network, Jessica Rae Gardner Douglas

Master's Theses

Three-dimensional reconstructions of marine fine-grained sediment open a new dimension for studying nano- and microscale organo-clay fabric important to improving and advancing organic matter (OM) sequestration and fluid flow dynamics modeling. I created 3-D reconstructions of clay fabric and pore pathways from serial sections and photographic mosaics obtained using transmission electron microscopy. These reconstructions show aggregations of clay domains, surrounding OM, and pore networks. I examined a Model sample (laboratory consolidated) with 1% OM and a Natural sample (polychaete fecal pellet) with high levels of OM. Three-dimensional reconstructions were segmented into 300 nm cube subsamples to make highly localized qualitative …

Role Of Il-17 In Cd8+ T Cell Mediated Clearance Of West Nile Virus, Jordan E. Lowery

Honors Theses

West Nile virus (WNV), a positive sense single stranded RNA flavivirus, is prevalent in many countries worldwide and is a growing threat in the United States. Some patients infected with WNV develop severe neuroinvasive disease including meningitis or encephalitis which may lead to death. The recently characterized cytokine interleukin-17 (IL-17) has been implicated in several autoimmune diseases, neuroinflammatory conditions, and immune responses to various microbial infections. Previous research has indicated that a known contributor to IL-17 production, interleukin-23, is produced in response to WNV infection, but the role of IL-17 during WNV infection has not been studied before. This study …

Population Genetics And Microbial Communities Of The Gopher Tortoise (Gopherus Polyphemus), Daniel Lyle Gaillard

Dissertations

The gopher tortoise, Gopherus polyphemus, is an endangered species living in the southeastern United States. The recent and drastic decline in tortoise numbers has resulted in a multi-faceted approach to conserve this species. I used a population genetic approach to determine the population structure, genetic diversity and barriers to gene flow at a broad, regional and local scale. Tortoises are divided into five distinct genetic populations at the broad scale, the central populations have the highest levels of genetic diversity and the Tombigbee, Mobile, Apalachicola, Suwannee and St. John’s Rivers appear to be barriers to gene flow. At the regional …

The Delivery, Speciation, And Fate Of Trace Elements In St. Louis Bay, Mississippi, Gopal Bera

Dissertations

Estuaries are dynamic regions in which there can be significant modification of the riverine flux of trace elements to the open ocean due to various geochemical, physical, and biological processes. Additionally, estuaries are often subject to anthropogenic inputs of trace elements. The first portion of this study investigated the source, behavior, and sediment interaction of anthropogenic stable cesium (Cs) in St. Louis Bay (SLB), MS. A consistent increase in stable Cs concentration was noticed in sediment cores starting from a period when a titanium dioxide refinery on SLB started operations. Weak correlation between Cs and clay percentage and strong correlations …

Biogeochemistry Of Trace Elements In The Mixing Zone Of The Mississippi And Atchafalaya Rivers And Chemical Distributions As Affected By The Deepwater Horizon Blowout, Dongjoo Joung

Dissertations

Selected trace elements (TEs), dissolved organic carbon, and nutrients were studied in Louisiana Shelf waters including the Mississippi (MR) and Atchafalaya (AR) River plumes during periods of high, intermediate, and low river discharges. Seasonal variations in TEs were observed at low salinity, reflecting seasonal changes in the river water endmembers. Shelf surface water dissolved Mo, Cs, U, Ni, and Cu showed conservative behavior with minor scattering in some high salinity waters. Based on associated mixing experiments, nutrient and chlorophyll distributions, as well as surface-bottom concentration contrasts, the non-conservative behavior of TEs was variously related to colloidal flocculation (Fe, Cr), biological …

Propagation Of Oligomeric Α-Synuclein And Amyloid-Β: Implications For Parkinson's And Alzheimer's Diseases, Matthew Stephen Planchard

Master's Theses

The aggregation of amyloidogenic proteins is a critical event in the pathology of a variety of neurodegenerative diseases, including Alzheimer’s disease (AD) and Parkinson’s disease (PD). The proteins α-synuclein (αS) and amyloid-β (Aβ) are involved in the formation of amyloid lesions observed in PD and AD, respectively. Both PD and AD exhibit a significant amount of co-pathology in clinical settings, and the αS and Aβ proteins have been shown to interact in vitro. Recent experimental consensus has shown oligomeric species to be significant, if not primary, sources of toxicity in these diseases. …

Study Of The Function Of The Mold Specific Gene Ms95 In Dna Repair In The Pathogenic, Dimorphic Fungus Histoplasma Capsulatum, Erin M. Smith

Honors Theses

Histoplasma capsulatum (Hc) is a dimorphic fungus that is the etiologic agent of the respiratory infection Histoplasmosis that is mediated by a shift from the mold phase to the pathogenic yeast phase. Genes have been identified that are specific to the mold or yeast phase in order to study the molecular biology of this shift. MS95 was identified in a subtractive cDNA library that was enriched for mold-specific genes, and has been found to be homologous to the DNA damage-responsive gene DDR48, which functions in DNA repair in Saccharomyces cerevisiae. In order to elucidate the function of MS95, a …

Carbon And Nitrogen Analysis To Determine Competitive Outcome For Three Species Of Container Mosquitoes, John Lloyd Martin

Honors Theses

It is well documented that intense larval competition exists between species of container mosquitoes. Two of the main genera of mosquitoes found to inhabit containers are Aedes and Culex. This study sought to determine the effects that different detritus treatments and larva ratios would have on carbon and nitrogen content, mass, and survival of larvae of various species. The species used in this experiment were Aedes albopictus, Aedes aegypti and Culex quinquefasciatus. I hypothesized that Ae. albopictus would be more efficient in acquiring nitrogen then the competitor species Ae. aegypti and Cx. quinquefasciatus. Thus, I expected Ae. albopictus to …

Cloning, Expression And Interaction Studies Of The Potential Rubisco Activase Cbbq, Salma A. Dawoud

Honors Theses

Carboxysomes are polyhedral microcompartments found in all cyanobacteria and in many chemoautotrophs. Within their shell they contain the enzyme ribulose-1, 5-bisphosphate carboxylase/oxygenase (RubisCO), which fixes CO₂. Downstream of the carboxysome operon there is another gene cluster containing several genes that may enhance carboxysome function. Two of these genes, cbbQ and cbbO, encode potential RubisCO activases. Using recombinant CbbQ and CbbO protein, and RubisCO isolated from carboxysomes the interaction between these proteins was studied. The CbbO and CbbQ proteins were both His tagged, allowing them to be purified with Ni²⁺-NTA column chromatography. Each of these tagged …