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Development And In Vivo Evaluation Of A Pura Mutant Strain Of The Channel Catfish Pathogen Edwardsiella Ictaluri., Mark Lee Lawrence
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 …
Relative Rates Of Molecular Evolution In Rodents And Their Symbionts., Theresa Ann Spradling
Relative Rates Of Molecular Evolution In Rodents And Their Symbionts., Theresa Ann Spradling
LSU Historical Dissertations and Theses
The focus of this dissertation is the relative tempo of molecular evolution among organisms of varying levels of relatedness. Because this is a rapidly expanding area of research, Chapter 1 is devoted to a review of the current state of knowledge on rates of molecular evolution. In Chapter 2, I present an analysis of relative rates of evolution among several distantly related rodents. The heterogeneity in rate of evolution of the cytochrome b gene observed here cannot be explained by metabolic rate, body size, generation time, or nucleotide-generation time. Likewise, there is no evidence that these differences in rate of …
The Evolution Of Landscapes And Lineages In Pitcher Plants And Their Moths., Margaret Ellen Oard
The Evolution Of Landscapes And Lineages In Pitcher Plants And Their Moths., Margaret Ellen Oard
LSU Historical Dissertations and Theses
Pitcher plants and pitcher plant moths exhibit two prominent themes in the long evolutionary history between plants and insects. These themes are carnivory and herbivory. In pitcher plants, the leaf has been modified into an elegant pitfall trap enabling these plants to subsist at both the producer and consumer trophic levels. Of the numerous insect species intimately associated with pitcher plants, pitcher plant moths are the only inquilines which have evolved the capacity to disrupt both the carnivore and photosynthetic functions of the host plant. The carnivorous habit, considered an adaptation for nutrient deficient environments, has contributed to species radiations …
Dna Wrapping And The Nature Of Interaction Between E. Coli Rna Polymerase And Promoter Dna., Parisa Jazbi
Dna Wrapping And The Nature Of Interaction Between E. Coli Rna Polymerase And Promoter Dna., Parisa Jazbi
LSU Historical Dissertations and Theses
Regulation of transcription most often occurs at the stage of initiation. RNA polymerase binding to the transcription start site, the promoter, is influenced by many nucleotide sequence elements. The predominant recognition sequences are those bound by the $\sigma$ subunit of RNA polymerase located at $-$10 and $-$35 relative to initiation site of most promoters. Another element involved in this regulation is intrinsic DNA curvature. In this study, the contribution of intrinsically curved DNA immediately upstream of the promoter to the interaction between Escherichia coli RNA polymerase and this DNA was examined. DNase I footprinting analysis confirmed that RNA polymerase wraps …
Phylogeny Of The Characeae (Charophyta) And Biogeography Of Chara (Characeae) Inferred From Ribosomal Rna Genes., Susan T. Meiers
Phylogeny Of The Characeae (Charophyta) And Biogeography Of Chara (Characeae) Inferred From Ribosomal Rna Genes., Susan T. Meiers
LSU Historical Dissertations and Theses
This dissertation examined generic, subsection, and infraspecific aspects of the phylogeny of the Characeae, and biogeography of Chara subsections and Chara haitensis. These relationships were inferred from cladistic and maximum likelihood analyses of sequence data for 18S and ITS regions of nuclear-encoded ribosomal RNA genes. Morphologically-based phylogenetic hypotheses of Wood and Imahori (1965) and Khan and Sarma (1984) concerning the six extant members of Characeae were tested. The analyses supported: monophyly of family Characeae, tribe Chareae, and of Lamprothamnium; placement of Nitellopsis basal to tribe Chareae; and an unresolved relationship between Lamprothamnium and Chara. Neither the hypothesis of Wood and …
Aerenchyma Development In The Freshwater Marsh Species Sagittaria Lancifolia L., Elisabeth Ellen Schussler
Aerenchyma Development In The Freshwater Marsh Species Sagittaria Lancifolia L., Elisabeth Ellen Schussler
LSU Historical Dissertations and Theses
Aerenchyma tissue consists of gas channels that provide a pathway for O$\sb2$ transport to waterlogged roots. Aerenchyma gas spaces are formed by cell separation or cell lysis during development. Light microscopy was used to determine how aerenchyma develops in Sagittaria lancifolia, a freshwater marsh species, when plants were grown in hydroponic solution. Petiole aerenchyma was formed by cell separation caused by differential cell expansion and division. In the root cortex, certain radial files of cells separated slightly from adjacent files and then lysed to form gas spaces. Development of root aerenchyma was characterized in S. lancifolia, Zea mays, and Oryza …
Rickettsia Felis, A Newly Discovered Rickettsia Associated With The Cat Flea (Ctenocephalides Felis Bouche)., Jimmy Wedincamp Jr
Rickettsia Felis, A Newly Discovered Rickettsia Associated With The Cat Flea (Ctenocephalides Felis Bouche)., Jimmy Wedincamp Jr
LSU Historical Dissertations and Theses
A study was performed to determine the life cycle of Rickettsia felis, a novel bacterium associated with cat fleas (Ctenocephalides felis Bouche). Cat flea populations maintain R. felis in successive generations by efficient transovarial transmission. Transovarial transmission was demonstrated in our study up to 12 generations. The mean infection rate for the progeny of fleas maintained on both cats and an artificial membrane system were comparable (64.3% and 58% respectively). Cats with no prior exposure to fleas were exposed to fleas infected with Rickettsia felis and monitored monthly for seroconversion via IFA. Blood samples were assayed for the presence of …
The Use Of Secondarily Treated Wastewater Effluent For Forested Wetland Restoration In A Subsiding Coastal Zone., John M. Rybczyk
The Use Of Secondarily Treated Wastewater Effluent For Forested Wetland Restoration In A Subsiding Coastal Zone., John M. Rybczyk
LSU Historical Dissertations and Theses
Insufficient sedimentation, coupled with high rates of relative sea-level rise (RSLR), are two important factors contributing to wetland loss in coastal Louisiana. I hypothesized that adding nutrient rich, secondarily treated, wastewater effluent to subsiding coastal wetlands in Louisiana could promote vertical accretion in these systems through increased organic matter production and subsequent deposition, and allow accretion to keep pace with estimated rates of RSLR (subsidence plus eustatic sea-level rise). To test this hypothesis, I measured processes affecting wetland elevation including, organic matter decomposition, sediment accretion, aboveground primary production, and, plant tissue nutrient (N, P, K, Ca, Mg, Fe) concentrations, in …
Pest Status And Management Of Beet Armyworm, Spodoptera Exigua (Hubner), On Cotton In Louisiana., Victor James Mascarenhas
Pest Status And Management Of Beet Armyworm, Spodoptera Exigua (Hubner), On Cotton In Louisiana., Victor James Mascarenhas
LSU Historical Dissertations and Theses
Field cage studies were conducted to measure the effects of late season beet armyworm, Spodoptera exigua (Hubner), infestations (0, 1, 3, and 6 egg masses per 5.1 row m) on defoliation, fruit damage, and yield of cotton. Light penetration through the canopy was significantly higher in infested plots. Although a trend for increased numbers of damaged fruiting forms with increases in egg mass density was observed, there were no significant differences between infested and control plots. There were no significant differences in the cumulative number of shed fruiting forms or yield between infested and control plots. Field tests were conducted …
Development Of Diagnostic Technology For Monitoring Pyrethroid Resistance Mechanisms In The Tobacco Budworm, Heliothis Virescens (F.)., Guomin Shan
LSU Historical Dissertations and Theses
Metabolic resistance was studied in the tobacco budworm, Heliothis virescens (F.) using pyrethroid analogs, insecticide synergists, and an in vitro assay with $\sp{14}$C-cypermethrin. In initial studies, the phenoxybenzyl moiety of conventional pyrethroid, a major site of oxidative metabolism in resistant H. virescens, was replaced with P450 monooxygenase-inhibiting or oxidatively blocked groups. Isomers (1R/1S, cis/trans) of the resulting chrysanthemates were separated and tested as insecticides against pyrethroid-susceptible (LSU) and -resistant H. virescens (Pyr-R). A number of compounds with pentafluorophenyl (PFP), methylenedioxyphenyl (MDP), and propargyloxyphenyl (PP) groups were insecticidal and activity was dependent on both geometric and stereochemical configuration of the acid …
Growth And Mortality Of Fish Larvae In The Northcentral Gulf Of Mexico And Implications To Recruitment., Bruce Henry Comyns
Growth And Mortality Of Fish Larvae In The Northcentral Gulf Of Mexico And Implications To Recruitment., Bruce Henry Comyns
LSU Historical Dissertations and Theses
Extensive plankton collections were taken during September for several years along the northcentral Gulf of Mexico's inner continental shelf. Significant differences in growth rates were found for both vermilion snapper and Atlantic bumper larvae collected at stations where hydrographic conditions were similar, indicating the probable existence of small-scale patchily-distributed feeding conditions. Such variability in growth rates is probably inevitable given the high variability in the observed spatial and temporal distribution of surface chlorophyll a levels, macrozooplankton biomass, copepod abundance, and dispersion of fish larvae. Cruise estimates of mortality coefficients (Z) for larval vermilion snapper, red drum, and Atlantic bumper were …
Genetics And Functions Of Herpes Simplex Virus Type 1 (Hsv-1) Glycoprotein K (Gk) In Virus Envelopment And Egress., Sukhanya Jayachandra
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
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 …
Seasonal Changes In Gnrh Neurons And Effects Of Dietary Monoamine Precursors On The Hypothalamic-Gonadal Axis In House Sparrows (Passer Domesticus)., Christopher Andrew Meseke
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 …
Cloning And Expression Of Capsid Proteins Of Hepatitis A Virus In Escherichia Coli., Lingaiah Chandrashekar
Cloning And Expression Of Capsid Proteins Of Hepatitis A Virus In Escherichia Coli., Lingaiah Chandrashekar
LSU Historical Dissertations and Theses
Hepatitis A virus (HAV), the causative agent of food and water borne acute hepatitis worldwide, is very difficult and expensive to propagate in tissue culture. Large scale production of HAV proteins in E. coli by recombinant DNA techniques would be invaluable for antisera production, biochemical analyses and in developing sensitive diagnostic tests. Therefore, PCR amplified DNA fragments encoding the HAV capsid proteins were cloned individually into prokaryotic expression vectors for production of either recombinant fusion or non-fusion proteins. Cloning and expression of HAV capsid genes, which induced toxic effects in certain host E. coli, was tolerated better by protease-deficient host …
Integrated Pest Management Tactics For Control Of Cabbage Looper And Diamondback Moth In Cabbage., Paul Wesley Ivey
Integrated Pest Management Tactics For Control Of Cabbage Looper And Diamondback Moth In Cabbage., Paul Wesley Ivey
LSU Historical Dissertations and Theses
Population density estimates, yield data, damage rating, and marketability of cabbage were used to assess the effectiveness of integrating several control tactics--an action threshold, host plant resistance, intercropping (companion planting), microbial control, and pesticide use reduction--for managing the diamondback moth (DBM), Plutella xylostella (L.), and the cabbage looper (CL), Trichoplusia ni (Hubner), in cabbage and in protecting beneficial arthropods. An action threshold of six DBM larvae per plant was inadequate for making insecticide application decisions because cabbage plots treated based on this action threshold had significantly higher densities of CL and DBM larvae, higher damage rating and yield loss, and …
Flight Muscle Histolysis In The Female House Cricket, Acheta Domesticus., Rush Hoyet Oliver
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 …
Activity Of Selected Insecticides Against The Soybean Looper, Pseudoplusia Includens (Walker), Using An Artificial Diet Overlay Bioassay Technique: Dosage Mortality, Discriminating Concentrations, And Resistance Monitoring., Rosanne Nicholson Mascarenhas
Activity Of Selected Insecticides Against The Soybean Looper, Pseudoplusia Includens (Walker), Using An Artificial Diet Overlay Bioassay Technique: Dosage Mortality, Discriminating Concentrations, And Resistance Monitoring., Rosanne Nicholson Mascarenhas
LSU Historical Dissertations and Theses
Diet overlay bioassays were conducted, evaluating insecticides requiring ingestion, on 3rd instar soybean loopers, Pseudoplusia includens (Walker). Laboratory reference and field strains were exposed to several insecticide concentrations, and LC$\sb{50}$s were compared. Field strains had significantly greater LC$\sb{50}$s than the reference strain when evaluating standard insecticides. Bioassays with experimental insecticides revealed few differences among strains. The diet overlay technique appears to be a viable method for monitoring insecticide resistance to these insecticides. Insecticide discriminating concentrations were determined using diet overlay bioassays to evaluate susceptibility of field and F1 generation, laboratory and field soybean looper strains. Field strains, exposed to permethrin …
Metamorphosis Of The Hawaiian Stream Goby Sicyopterus Stimpsoni: A Structural, Functional, And Behavioral Analysis., Heiko Lars Schoenfuss
Metamorphosis Of The Hawaiian Stream Goby Sicyopterus Stimpsoni: A Structural, Functional, And Behavioral Analysis., Heiko Lars Schoenfuss
LSU Historical Dissertations and Theses
The endemic goby Sicyopterus stimpsoni is unique among five species of Hawaiian freshwater fishes because it undergoes rapid metamorphosis of cranial structures during postlarval development. These fishes are amphidromous and return after a prolonged stay in the ocean to streams where they are confined to estuaries until completion of cranial restructuring. Within 48 hours after entering fresh water, head width increases significantly, while total length and head length remains unchanged. Weight decreases by approximately 15% during this period. The upper lip enlarges greatly, and the mouth position shifts from terminal to nearly ventral. Shape analysis of radiographs taken from a …
Non-Conservative Behavior Of Select Naturally-Occurring Radionuclides And Metals In Coastal Waters., Peter Wolfgang Swarzenski
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 …
The Polysaccharide Capsule Of Vibrio Vulnificus: Virulence, Transposon Mutagenesis, And The Identification Of An Essential Gene., Amy Buscher Zuppardo
The Polysaccharide Capsule Of Vibrio Vulnificus: Virulence, Transposon Mutagenesis, And The Identification Of An Essential Gene., Amy Buscher Zuppardo
LSU Historical Dissertations and Theses
The extracellular capsule polysaccharide (CPS) of Vibrio vulnificus is a primary virulence factor which allows survival of the bacteria in the human host. To study the genes involved in the production of the polysaccharide capsule, 23 mutants were generated that lost their ability to produce CPS due to the insertion of a mini-transposon into the genome of the encapsulated clinical strain V. vulnificus 1003 (O). The mutants were examined by Southern blot analysis to ensure the transposon had inserted only once in the chromosome. Exoenzymes, which are believed to contribute to the virulence of the organism, produced by all 23 …
Macrofaunal Community Structure In The Introduced And Native Submerged Macrophyte Beds Of The Lake Pontchartrain Estuary., Kenneth Charles Duffy
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 …
The Radioresistance Of Deinococcus Radiodurans., Valerie Mattimore
The Radioresistance Of Deinococcus Radiodurans., Valerie Mattimore
LSU Historical Dissertations and Theses
Deinococcus radiodurans is a remarkably ionizing radiation resistant bacterium. As a vegetative cell it is capable of withstanding 5,000 Gy ionizing radiation without evidence of death or mutation. D. radiodurans survives irradiation by repairing DNA damage via an extremely efficient DNA repair system. However, this DNA repair system has not been completely defined. In addition, the selective process allowing the evolution of high level radioresistance has remained a question. This dissertation bolsters the understanding of the DNA repair system of D. radiodurans by characterizing a collection of ionizing radiation sensitive (IRS) mutants. The level of radioresistance is quantified and transformation …
The Uptake And Distribution Of Diethyltoluenediamine In The Male Sprague Dawley Rat., Michael Charles Babin
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 …
Caprine Sperm Cells As Vectors For Gene Transfer., Yongxin Sun
Caprine Sperm Cells As Vectors For Gene Transfer., Yongxin Sun
LSU Historical Dissertations and Theses
Goat sperm cells were used as a model to evaluate sperm-mediated gene transfer. Fresh and frozen-thawed goat sperm cells were co-incubated with radio-labelled foreign DNA. After 10 extensive washings, the compacted sperm retained foreign DNA. Confocal microscopy confirmed that the position on the sperm cell responsible for binding of foreign DNA was located in both the anterior and the posterior heads of caprine sperm cells. Furthermore, confocal longitudinal sections of the sperm cells showed that foreign DNA had penetrated into goat sperm nuclei. In this study, 37% of the fresh goat sperm and 33% of the frozen-thawed goat sperm cells …
Causes Of Vegetation Dieback And Subsequent Wetland Loss In Two Louisiana Coastal Marshes., Eric Courtney Webb
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 …