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Biology And Ecology Of The Anopheles Quadrimaculatus Sibling Species Complex In Louisiana., Cynthia Roxanne Rutledge

LSU Historical Dissertations and Theses

A polymerase chain reaction method for identifying individuals in the Anopheles quadrimaculatus Say sibling species complex was validated for wild mosquitoes from Louisiana and Mississippi. This method distinguished An. quadrimaculatus species A, B, C, and D by detecting species-specific differences in the 2nd internal transcribed spacer of ribosomal DNA and was 100% specific and 95% sensitive. A polymerase chain reaction assay that detects differences in the second internal transcribed spacer of ribosomal DNA was tested for its usefulness in identifying all immature stages of two representatives in the An. quadrimaculatus sibling species complex. The technique was successful in amplifying DNA …

Phylogenetic Placement Of African Cornus: Evidence Of Nuclear Rdna, Scott Myers

Mahurin Honors College Capstone Experience/Thesis Projects

The genus Comus (the dogwoods) contains 50 species that have been divided into nine subgenera. One of these species, C. volkensii, has been segregated into the subgenus Ajrocrania. Previous studies combined morphological, anatomical, and chemical data to produce a hypothesis of evolutionary relationships that placed the subg. Afrocrania as a segregate lineage sister to the subg. Comus, and placed the Ajrocrania/Comus lineage sister to the big-bracted dogwoods (Murrell 1997). The subgenus Afrocrania has been examined morphologically, anatomically, and palynologically; however, it was not sequenced in Xiang's (1993) analysis of rbcL (chloroplast) sequence data, or in her analysis of the matK …

Modulation Of The Rat Potassium Channel Kv1.5, Daniel Benjamin Saal

Yale Medicine Thesis Digital Library

1. Kv1.5 is a delayed rectifier-type potassium channel. We have examined the localization of the channel protein using a polyclonal antibody against Kv1.5. This channel is expressed in numerous regions of the brain, primarily in glial cells. Its expression is particularly intense in the endfoot processes which abut the microvasculature of the brain. It is also expressed in the cell bodies and cellular processes in the pituitary.2. Immunoprecipitation of the Kv1.5 protein, from HEK 293 cells which were transformed with the Kv1.5 gene, revealed that the channel is phosphorylated and that treatment of cells with dibutyryl cyclic AMP (dibcAMP) or …

Biology Of Shovelnose Sturgeon, Scaphirhynchus Platorynchus, In The Lower Platte River, Nebraska, Robin L. Hofpar

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

Teaching General Biology For Nonmajors Through Community Service Projects, Mary Wells Phillips

Higher Education

For many students, especially for the biology nonmajors, science is often one of the last courses they take before completing their degree. Often, these students enter my course with a previous "bad" experience from courses in high school or have developed anxieties regarding what science is all about. They are reluctant learners who frequently shy from questions and classroom discussions. Their own insecurities and presumed lack of knowledge frequently !eaves them floundering and confused. The message is, "I am here because I need 'x' number of science units before completing my degree."

A Transcription-Dependent Switch Controls Competence Of Adult Neurons For Distinct Modes Of Axon Growth, Deanna S. Smith, J.H. Pate Skene

Faculty Publications

Although maturing neurons undergo a precipitous decline in the expression of genes associated with developmental axon growth, structural changes in axon arbors occur in the adult nervous system under both normal and pathological conditions. Furthermore, some neurons support extensive regrowth of long axons after nerve injury. Analysis of adult dorsal root ganglion (DRG) neurons in culture now shows that competence for distinct types of axon growth depends on different patterns of gene expression. In the absence of ongoing transcription, newly isolated neurons can extend compact, highly branched arbors during the first day in culture. Neurons subjected to peripheral axon injury …

Development And Application Of Molecular Techniques For The Detection Of Human Enteric Viruses In Environmental Samples, Patrick Michael Regan

Doctoral Dissertations

Shellfish and water have been implicated in the transmission of viral diseases. National surveillance data on waterborne and foodborne illnesses underestimate the public health significance of these viruses. The focus of this research was to evaluate, develop, and apply molecular techniques to detect human enteric viruses in environmental samples.

The initial study evaluated a nucleic acid hybridization assay using a $\sp{32}$P labeled cDNA probe to detect poliovirus in clams. Clams (Mercenaria mercenaria) were harvested from Narragansett Bay, Rhode Island. Poliovirus was detected in clams from the conditionally approved area in 3 of 9 collections and in the prohibited area in …

Predation By Nucella Lapillus (Linnaeus, 1758) On Littorina Obtusata (Linnaeus, 1758) And Mytilus Edulis (Linnaeus, 1758), Helena Matthews Cascon

Doctoral Dissertations

Prey preference and recognition by individuals of Nucella lapillus from 13 different populations from New England were studied, to determine if individuals of this species kept on a single prey diet develops a preference for this prey, and if prey availability affects prey recognition in this predator. Individuals from all 13 populations showed a preference for Mytilus edulis over Littorina obtusata in laboratory experiments, including those from a population that prey only on L. obtusata in the field. Individuals from another population were not able to recognize L. obtusata as a prey. N. lapillus kept in a diet of M. …

Molecular Characterization Of A Cytotoxic Porin Protein From Campylobacter Jejuni And Its Role In Campylobacteriosis, David John Bacon

Doctoral Dissertations

Campylobacter jejuni is a major cause of enteritis in developed and developing countries. A cytotoxic complex was isolated from organism-free filtrates of broth grown organisms by screening for activity in HEp-2 cells following high performance liquid chromatography using a combination of size exclusion and DEAE column chromatography. The toxin was found to coincide with a 45 kDa protein possessing an N-terminus sequence indicative of a bacterial outer membrane porin protein together with a high molecular weight carbohydrate which was determined to be lipopolysaccharide (LPS).

The carbohydrate portion of the LPS had reactivity for the lectins Galanthus nivalis agglutinin, Maakia amurensis …

Numerical Analysis For Blood Distribution In Complete Flow Cross-Section Microvascular Networks, Jewen Xiao

Doctoral Dissertations

As the blood flows through a bifurcation, the axisymmetric red blood cell concentration profile is skewed by plasma skimming. In the downstream segment of the bifurcation the concentration profile of red blood cells recovers symmetry by the red blood cell dispersion process.

In this study, the concentration convective equation, which models the red blood cell dispersion process, is solved with the method of finite differences in cylindrical coordinates. In the computation, a shear-induced diffusivity coefficient is used. The computed hematocrit ratios at the second bifurcation are compared with in vitro experimental data obtained from 50 $\mu$m serial trees with two …

Phylogenetic Diversity And Community Structure Of Sulfate-Reducing Bacteria In A Salt Marsh Sediment, Juliette Nicole Rooney Varga

Doctoral Dissertations

Phylogenetic diversity and community structure of sulfate-reducing bacteria (SRB) in a salt marsh sediment and rhizosphere of Spartina alterniflora were investigated. Uncultivated phylotypes were studied by selectively amplifying Desulfobacteriaceae 16S rRNA gene fragments from DNA extracted from salt marsh rhizosphere samples. An in vitro transcription technique was developed to synthesize reference RNAs containing sequences presumably identical to corresponding regions of the uncultivated organisms' 16S rRNAs. These reference RNAs were used in subsequent quantitative probing experiments. Oligonucleotide probes were designed to specifically target novel phylotypes and were tested for optimal hybridization wash conditions and target specificity. The newly designed probes were …

Variation In Reproductive Success Within A Natural Population Of The American Toad (Bufo Americanus), Paulo Cascon

Doctoral Dissertations

The purpose of this study was to investigate if mating success and clutch size are good estimates of reproductive success in a population of Bufo americanus, through the study of the contribution of life history parameters to the variation in individual reproductive success. A B. americanus population that breeds in a pond located in Madbury, NH was studied during the 1994, 1995 and 1996 mating seasons. In 1995 and 1996 clutches were also studied and the larvae were used in laboratory and field experiments. The following fitness parameters were investigated: mating success, clutch and egg size, growth rate and survivorship …

A Biosystematic Monograph Of The Genus Nuphar Sm (Nymphaeaceae), Donald Jay Padgett

Doctoral Dissertations

The genus Nuphar (Nymphaeaceae) comprises 10 perennial species native to freshwaters of the Northern Hemisphere. This taxonomic assessment utilizes morphometric analyses, cladistic analyses of morphology, nuclear and chloroplast DNA sequences, evaluation of randomly amplified polymorphic DNA, and pollen fertility estimations. Evolutionary reconstructions position Nuphar at the base of the family, most closely allied to Barclaya. Phylogenetic estimates within Nuphar indicate two major evolutionary lines, largely congruent with present biogeographical distributions that indicate an Old World/New World divergence. Accordingly, the genus is subdivided into two sections, Nuphar and Astylata. Section Nuphar includes the type of the genus, N. lutea, as well …

Neuroethology Of The Swimming Behavior In The Pacific Nudibranch, Melibe Leonina, Kathryn Ann Lawrence

Doctoral Dissertations

Melibe leonina is a subtidal nudibranch which is found in association with eelgrass and kelp. Melibe swims when disturbed, or knocked off of its substrate, by slow lateral undulations. Swimming is stereotyped in its form and execution, and can be reliably reproduced in the laboratory. Swimming consists of phases: (1) withdrawal, (2) flattening, (3) lateral flexions, (4) unfolding and swinging and (5) termination. Swimming can be reliably elicited using 1M KCl or contact with the tube feet of the predatory seastar Pycnopodia helianthoides. The duration of a single swim cycle and the amplitude of swimming flexions remain relatively constant, however, …

Foraging Strategies Of Two Sympatric Lagomorphs: Implications Of Habitat Fragmentation, Douglas Foxall Smith

Doctoral Dissertations

I studied the effects of variation in food patch quality and predation risk on the foraging patterns and measures of foraging behavior of New England (S. transitionalis) and eastern (S. floridanus) cottontails, and their survivorship and weight change during these experiments. I then superimposed the results of these experiments onto real habitat patches to determine the amount of habitat each species could occupy and maintain similar survivorship. Finally, I measured an adaptation (eye size), and predator detection of both species in an effort to explain the difference in survival between S. floridanus and S. transitionalis.

In outdoor enclosures (5.7 x …

The Use Of An Artificial Light System To Assess The Influence Of Relative Light Change On Diel Activity Cycles Of Nymphs Of The Mayfly, Stenonema Modestum, In The Presence And Absence Of Predators, Annette L. Schloss

Doctoral Dissertations

A mechanism by which light controls diel changes in locomotor activity and surface location of mayfly nymphs (Stenonema modestum Banks), named the Stimulus-based Timing and Activity-Rate (STAR) Model, was tested. Nymph movements were video-recorded in time-lapse from underneath unglazed artificial substrates in a laboratory stream. Light/dark cycles were simulated using computer-controlled halogen lamps. Light increases and decreases were generated to maintain constant rates of relative light change throughout simulated twilight periods. Nymph locomotor activity and position on the substrate were measured in response to rate of light change. Experiments tested whether adaptation light intensity (10$\sp{-4}$ or 10$\sp{-6}$ W cm$\sp{-2}$), time …

Receptors And Ligands Involved In The Recognition Of Group B Streptococci By Human And Bovine Phagocytic Cells, Lesley Mary Smith

Doctoral Dissertations

Macrophages have been shown to bind pathogenic microorganisms in the absence of exogenous opsonins, but the precise mechanisms are poorly understood. Microbial recognition by macrophages under these conditions becomes particularly important in individuals who have decreased amounts of opsonins such as immunocompromised individuals and neonates. This study was undertaken to investigate the mechanisms of adherence between group B Streptococcus and macrophages in opsonin-limiting conditions. Using several adherence assays; visual binding, enzyme-linked immunosorbent, and flow cytometry, GBS was able to adhere to U937 cells, a human macrophage-like cell line, in a dose-dependent manner without exogenous opsonins.

The $\beta\sb2$ integrins, a heterodimeric …

Systematics Of The Hamamelidaceae Based On Morphological And Molecular Evidence, Jianhua Li

Doctoral Dissertations

The Hamamelidaceae are a plant family of 31 genera and more than 140 species distributed in both the Old and New worlds. There has long been debate about the subfamilial, tribal, as well as generic, relationships within the family.

Parsimony analysis was performed to examine the relationships in the Hamamelidaceae based on morphology, and DNA sequences of the Internal Transcribed spacers (ITS) of nuclear ribosomal DNA, and the chloroplast matK gene. The morphology-based phylogeny shows weak support for all clades except for the Altingioideae, and differs greatly from the molecular phylogenies. Phylogenies based on the matK and ITS data are …

Investigation Of The Mechanism Of Adr1 Mediated Transcriptional Activation, Philip B. Komarnitsky

Doctoral Dissertations

The purpose of these studies was to examine the mechanism of function of the transcriptional activator ADR1 of yeast Saccharomyces cerevisiae. ADR1 is required for the activation of the ADH2 gene, as well as genes involved in glycerol metabolism and peroxisome biogenesis. ADR1 is a DNA-binding protein. It binds to a 22 bp palindromic upstream activating sequence 1 (UAS1) element located 215 bp 5$\sp\prime$ to the transcription start site of ADH2. Elements similar to UAS 1 are found in promoters of all ADR1-dependent genes. ADR1 was shown previously to contain three transcriptional activation domains (TADs): TADI (amino acids 76-172), TADII …

Internal Oral Anatomy: A Comparative Analysis Of The Phyllomedusinae (Anura:Hylidae), Erin B. Hines

Honors Theses

The internal oral anatomy of phyllomedusines has only been described for Agalychnis callydrias using light microscopy. Herein, we compare the internal oral anatomy of the genera Phyllomedusa, Agalychnis, Pachymedusa, and Phasmahyla, using SEM methodology. Tadpoles of ten species were prepared using standard SEM techniques; these larvae ranged from Gosner stages 34-39. Phasmahyla has a unique prenarial arena with three well developed pre-narial arena papillae, whereas the other genera possess the prenarial arena papillae in a semicircular arrangement with the opening directed posteriorly. Pachymedusa differs from Phyllomedusa and Agalychnis by having a low, straight-edge, median ridge; also, its buccal floor arena …

Porin Proteins Of Salmonella Typhimurium Mediate Adherence To Macrophages, Robert Solomon Negm

Doctoral Dissertations

Salmonellosis continues to be a major infectious disease in both the United States and elsewhere. The outer membrane porin proteins (Omp) from Salmonella typhimurium play a key role in the initial adherence of this microorganism to murine macrophages and this mechanism is a critical event in the pathogenesis of infections. In this study macrophages were found to make contact with an OmpC-like protein of S. typhimurium and inhibition assays using the purified protein significantly reduced bacterial binding to macrophage. The ompC gene in a strain of S. typhimurium that is resistant to killing by macrophage was inactivated by transposon mutagenesis. …

Non-Conservative Behavior Of Select Naturally-Occurring Radionuclides And Metals In Coastal Waters., Peter Wolfgang Swarzenski

LSU Historical Dissertations and Theses

Water column samples from three vastly contrasting coastal regimes (Framvaren Fjord, Norway, the Amazon and Mississippi River outflow regions) were analyzed to study the estuarine transport and scavenging processes of $\sp{210}$Pb, $\sp{210}$Po, $\sp{234}$U and $\sp{238}$U. The Amazon and Mississippi River outflow regions are two of the world's largest river-ocean mixing systems that contrast each other sharply in many physiographical and geochemical features. The Amazon is a tropical, high energy, shelf environment where estuarine physico-chemical processes are strongly influenced by sediment-water interactions. The Mississippi system on the other hand discharges much of its load close to the shelf-break where estuarine geochemical …

Seasonal Changes In Gnrh Neurons And Effects Of Dietary Monoamine Precursors On The Hypothalamic-Gonadal Axis In House Sparrows (Passer Domesticus)., Christopher Andrew Meseke

LSU Historical Dissertations and Theses

Mechanisms modulating avian seasonal reproduction involve a complex interaction between exogenous environmental information and internal physiologic systems, such as functional changes in the hypothalamic-gonadal axis and changes in the influence of monoaminergic neurotransmitters on hypothalamic neuroendocrine cells. This project was undertaken to describe seasonal changes of the testes and immunoreactive-(ir)-gonadotropin-releasing hormone (GnRH) neurons in House Sparrows in southeastern Louisiana, and to examine the role of monoaminergic neurotransmitters in modulating seasonal reproduction through the use of dietary monoamine precursors. Testicular weights rapidly increased from February to March, peaked from April to July, when the seminiferous tubules were spermatagenically active and filled …

The Uptake And Distribution Of Diethyltoluenediamine In The Male Sprague Dawley Rat., Michael Charles Babin

LSU Historical Dissertations and Theses

Diethyltoluenediamine (CAS 68479-98-1) is a ring-ethylated analog of toluenediamine (TDA) and like TDA, consists of the 2,4- and 2,6-diamine isomers. DETDA was developed by Albermarle Corporation as a substitute for TDA in some applications. To determine the uptake and distribution of 2,4- and 2,6-DETDA, 5 groups of 4 adult male Sprague Dawley rats were gavaged at 179 $\mu$mol/kg body weight with ($\sp3$H) -2,4- or ($\sp3$H) -2,6-DETDA. Multiple tissues were collected at 1, 4, 8, 24 and 48 hours. Very high levels of label occurred in the gastrointestinal system and bladder during the first 8 hours while liver and kidney exhibited …

Flight Muscle Histolysis In The Female House Cricket, Acheta Domesticus., Rush Hoyet Oliver

LSU Historical Dissertations and Theses

Flight muscle histolysis was investigated in the dorsal longitudinal muscles (DLMs) of the cricket. Histolysis in the DLMs was characterized by analysis of total protein content, tissue wet weight, and relative percent muscle shortening. Initial declines of total protein indicated the JH signal initiating histolysis occurred by Day 2. Histolysis was essentially complete by Day 3. Ligation of Day 1 crickets prevented histolysis but this inhibition could be prevented by continual topical treatments with methoprene. Ligation of Day 2 crickets did not prevent histolysis. A requirement for active protein expression was demonstrated by analysis of synthesis block by cycloheximide and …

Genetics And Functions Of Herpes Simplex Virus Type 1 (Hsv-1) Glycoprotein K (Gk) In Virus Envelopment And Egress., Sukhanya Jayachandra

LSU Historical Dissertations and Theses

HSV-1(KOS)$\Delta$gK, a virus lacking the UL53 gene coding for glycoprotein K(gK) was constructed, characterized and compared to the partially deleted gK-null virus HSV-1(F)-gK$\beta$. $\Delta$gK and F-gK$\beta$ viruses produced microscopic plaques on Vero cells at 48 hours post infection. F-gK$\beta$ plaques at 72 hours post infection contained fused cells (syn), while $\Delta$gK plaques resembled wild-type KOS plaques ($syn\sp+$). $\Delta$gK replicated efficiently in exponentially dividing Vero cells whereas F-gK$\beta$ yields were 10 and 1000-fold lower than $\Delta$gK yields in HEp-2 or log-phase Vero cells, respectively. Electron micrographs of $\Delta$gK-infected Vero cells revealed large numbers of capsids in the nuclei of Vero, but …

Cloning, Sequencing And Regulation Of The Rhodobacter Capsulatus Hemh Gene., Ekaterina Vladislavova Kanazireva

LSU Historical Dissertations and Theses

Rhodobacter capsulatus, a purple non-sulfur photosynthetic bacterium, synthesizes four tetrapyrrole end products: heme, bacteriochlorophyll, siroheme and vitamin B$\sb{12}$ via the common tetrapyrrole biosynthetic pathway. The biosynthesis of tetrapyrroles in R. capsulatus is a complex and precisely controlled process which has been under extensive investigation. In order to study the regulation of tetrapyrrole biosynthesis, the R. capsulatus hemH gene was cloned by complementation of an E. coli $\Delta hemH$ mutant and sequenced. The enzyme ferrochelatase, encoded by the hemH gene, catalyzes the insertion of ferrous iron into protoporphyrin IX, thus producing heme. The consensus ferrochelatase signature sequence was found in the …

Macrofaunal Community Structure In The Introduced And Native Submerged Macrophyte Beds Of The Lake Pontchartrain Estuary., Kenneth Charles Duffy

LSU Historical Dissertations and Theses

Introductions of exotic aquatic plants raise concerns for the health of assemblages of native species. The possible influence of the establishment of the exotic Eurasian watermilfoil Myriophyllum spicatum on fish and invertebrate assemblages in the Lake Pontchartrain estuary was examined with a microhabitat approach. Fish and invertebrate assemblage structure and population responses were compared among macrophyte species and unvegetated areas. Native macrophytes included wild celery Vallisneria americana and wigeongrass Ruppia maritima. Additionally, the relationships of the common submerged macrophytes to environmental and temporal variables were analyzed. A total of 517 samples, collected with a modified Wegener ring, included 3,564 fishes …

Development And In Vivo Evaluation Of A Pura Mutant Strain Of The Channel Catfish Pathogen Edwardsiella Ictaluri., Mark Lee Lawrence

LSU Historical Dissertations and Theses

Edwardsiella ictaluri is the causative agent of enteric septicemia of catfish (ESC), which is the most serious disease affecting the channel catfish industry. Killed vaccines have been inconsistent in providing protection against ESC, and no live attenuated vaccines have been described. The purpose of this study was to develop a nutritionally attenuated mutant strain of E. ictaluri and evaluate its virulence and vaccine efficacy. An E. ictaluri genomic library was constructed, and a clone containing the purA gene was isolated and sequenced. The E. ictaluri purA gene was found to have several features in common with the E. coli purA …

Causes Of Vegetation Dieback And Subsequent Wetland Loss In Two Louisiana Coastal Marshes., Eric Courtney Webb

LSU Historical Dissertations and Theses

Vegetation dieback is an important component of the wetland loss process in coastal Louisiana. To determine the factors causing vegetation dieback in a Louisiana salt marsh and oligohaline marsh, field monitoring and manipulative field experiments were conducted in both marsh types. In the salt marsh, a three-year field study was conducted in which biotic and edaphic characteristics were measured and the effect of elevation on four salt marsh plant species was tested in a manipulative field experiment. In the oligohaline marsh, a two-year field study was conducted which evaluated the relationship between biotic and edaphic characteristics. Additionally, the effects of …