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I. Photophysics And Photochemistry Of Molybdenum-Oxo Complexes. Ii. Synthesis Of A Ferrocene-Based Monomer For Use In Ring-Opening Metathesis Polymerization., Ralph Isovitsch

LSU Historical Dissertations and Theses

The brick-red ferrocenophene 1,4-(3,3$\sp\prime$-bis(1,1-dimethylpentyl)-1,1$\sp\prime$-ferrocenediyl) -1,3-butadiene was prepared via a six-step synthetic route. It was isolated and characterized for use as a monomer in Ring Opening Metathesis Polymerization. Fluorescent molybdenum(V)-oxo complexes such as $\rm MoOCl\sb4(H\sb2O)\sp-$ undergo thermal and photochemical reactions with the series of phosphines $\rm PEt\sb2,\ PEt\sb3Ph,\ PEtPh\sb2$ and PPh$\sb3$ as oxygen atom acceptors. PEt$\sb3$ reacts spontaneously to form several products: $\rm (PPh\sb4)\lbrack MoCl\sb4(PEt\sb3)\sb2\rbrack,\ (PPh\sb4)\sb2\lbrack MoOCl\sb5\rbrack{\cdot}2CH\sb2Cl\sb2,$ and a maroon oil that contains $\rm OPEt\sb3,\ MoOCl\sb2(PEt\sb3)\sb3$ and $\rm MoCl\sb4(PEt\sb3)\sb2.$ Both $\rm (PPh\sb4)\lbrack MoCl\sb4(PEt\sb3)\sb2\rbrack$ and OPEt$\sb3$ are products of an oxygen atom transfer reaction. PEt$\sb2$Ph and PEtPh$\sb2$ also produce the corresponding phosphine …

Reduction And Management Of Risks Associated With Aflatoxin And Fumonisin Contamination In Corn., Socrates Trujillo

LSU Historical Dissertations and Theses

Aflatoxins and fumonisins, secondary mold metabolites, occur naturally as co-contaminants in corn. Health and economic risks associated with this contamination of food and feed have been the focus of much research worldwide. Research programs resulting from the discovery of aflatoxins in the 1960's has been used to guide study programs for fumonisins. The establishment of food safety programs, including mycotoxin decontamination procedures, must be evaluated for further application. The evaluation of selected procedures which reduce the risks associated with the contamination of these mycotoxins in food utilized for human and animal consumption was the focus of this study. This study …

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 …

High-Resolution Facies Analysis Of Deltaic Subenvironments Of The Pennsylvanian Atoka Formation, Arkansas., Tanwi Gangopadhyay

LSU Historical Dissertations and Theses

The present research was aimed at comparison and distinction between various deltaic subenvironments from Pennsylvanian deposits of the Arkoma Basin, Arkansas. Detailed facies analysis of deltaic deposits reveal significant variation in sedimentary characteristics between different subenvironments. A multi-pronged approach, including documentation of measured sections and gamma ray profiles in the field and subsequent laboratory analysis of samples, was undertaken. The Atoka Formation deltaic deposits have been established primarily as representing fluvially-dominated deltas. Interdistributary bay fill deposits are splintery shales with abundant siderite nodules. Crevasse splay sandstone units are ripple cross-laminated and coarsen and thicken upward to a maximum of 60cm …

Production Of Transgenic Channel Catfish., Mark Christian Bates

LSU Historical Dissertations and Theses

The channel catfish industry has experienced tremendous growth over the last several years. This growth has triggered more intensive culture practices resulting in disease outbreaks and devastating mortalities. Medicated feeds and vaccination have been of limited use. This research presents studies on techniques to produce disease resistant channel catfish by gene transfer. The gene used was the cecropin B gene from the giant silkworm moth Hyalophora cecropia, controlled by an acute phase response (APR) promoter also from H. cecropia. The objectives of this study were to: (1) determine if an early maturing population of catfish from Lake Maurepas, Louisiana, could …

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 …

Characterization Of Bean Eukaryotic Translation Initiation Factor 5: Cloning, Sequencing, And Structure-Function Studies., Zelpha Elizabeth Floyd

LSU Historical Dissertations and Theses

Translation initiation is emerging as one of the important mechanisms involved in regulation of gene expression and our understanding of this process in eukaryotes has greatly increased over the past twenty years. Research in translation initiation in plants has lagged behind efforts in the mammalian system and a number of the initiation factors have not been characterized. Eukaryotic initiation factor 5 (eIF5), the protein mediating hydrolysis of the eIF2-bound GTP and the subsequent formation of the 80S ribosome, is among the least characterized initiation factor in plants. This dissertation describes the cloning of the cDNA encoding eIF5 from a bean …

Self-Schemata For Sport And Physical Activity: The Influence Of Race And Gender., Louis Harrison Jr

LSU Historical Dissertations and Theses

The most recent Surgeon General's report underscores the need for increased levels of regular physical activity in the general population, and in women and minorities in particular. Variations in participation patterns in particular sports and physical activities may provide insight into the reasons for differing activity levels in women and minorities. The present investigation studied the influence of race and gender on activity choices by regarding specific sport and physical activities as self-defining for race and gender groups. Study 1 was designed to confirm the existence of self-schemata for sport and physical activities. A computer generated instrument was employed to …

Identification Of The Physiological Role Of Carbonic Anhydrase Using The Antisense Technique, And, Investigation Of Its Transcriptional Regulation In Arabidopsis Thaliana (L.) Heynh., Hee Jin Kim

LSU Historical Dissertations and Theses

Carbonic anhydrase (CA, EC 4.2.1.1), catalyzes the interconversion of CO$\sb2$ and $\rm HCO\sb3\sp-$ in many organisms. The majority of CA activity in C3 leaves is in the chloroplast and expression of the chloroplast CA is regulated by light. To investigate the physiological role of the chloroplast CA, its expression was suppressed by insertion of a CA transgene in the antisense orientation in Arabidopsis thaliana (L.) Heynhold. Activity assays and immunoblots show that in five independent lines of antisense transgenic plants CA activity was strongly suppressed. All five independent lines died or grew poorly in the absence of sucrose whereas wild …

The Recycling Potential Of Out-Of-Service Utility Poles For Engineered Wood Products., Han Roliadi

LSU Historical Dissertations and Theses

This study on the recycling potential of out-of-service poles for use in engineered wood products involved determination of basic properties of used southern pine (Pinus sp.) utility poles and also manufacture of glued-laminated beams from these poles. Most of the defect-free portions of 25-year treated poles still retained adequate strengths comparable to those of freshly treated poles and untreated southern pine. Creosote contents, however, diminished with pole ages. The reduction in creosote content was correlated with lower decay resistance, poorer dimensional stability, and lower lumber recovery, but better gluability. The spectrometry method for creosote content determination was explored as an …

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 …

Etiology And Biological Control Of Seedling Disease In Water-Seeded Rice., Se-Chul Chun

LSU Historical Dissertations and Theses

In order to assess the potential of biological control of rice seedling disease, detailed etiological information was required, i.e. when and for how long are seedlings susceptible and which portions of the seed and seedling are susceptible. Contaminant-free seeds were required for these studies. For this purpose, rice seeds were soaked for 2 hrs in freshly prepared 2.6% sodium hypochlorite adjusted to pH 7.0 with a final concentration of 0.5 M potassium phosphate. This treatment was not only very effective in disinfesting seeds but also seemed to promote seedling growth. On the basis of this observation, a study was conducted …

Potential For Glufosinate As A Selective Herbicide For Red Rice Control In Bar-Transformed Rice., Sujatha Sankula

LSU Historical Dissertations and Theses

A three year study was conducted to evaluate the herbicide glufosinate on BAR-transformed rice and on the weed red rice. Preliminary evaluations with 1.1 and 2.2 kg/ha glufosinate on the BAR-transformed Gulfmont and Koshihikari rice varieties showed that both were resistant, but there was more injury to Koshihikari. Glufosinate at 2.2 kg ai/ha injured BAR-transformed Gulfmont rice more when applied to the 1- to 2-leaf stage (23-26%) than when applied to 3- to 4-leaf (13-19%) plants. The damage was least with boot stage applications (3-14%). Phytotoxicity to BAR-transformed Gulfmont rice was greater when 2.2 kg/ha glufosinate was combined with 0.4 …

The Redox State Of The [2fe-2s] Clusters In Soxr Protein Regulates Its Activity As A Transcription Factor, Huangen Ding, Elena Hidalgo, Bruce Demple

Faculty Publications

SoxR protein is a redox-responsive transcription factor that governs a regulon of oxidative stress and antibiotic resistance genes in Escherichia coli. Purified SoxR contains oxidized [2Fe-2S] clusters and stimulates in vitro transcription of its target gene soxS up to 100-fold. SoxR transcriptional activity, but not DNA binding, is completely dependent on the [2Fe-2S] clusters; apo-SoxR prepared in vitro binds the soxS promoter with unchanged affinity but does not have transcription activity. Thus, modulation of the SoxR [2Fe-2S] clusters was proposed to control the protein's function in transcription. Here, we provide evidence that SoxR with reduced [2Fe-2S] clusters is inactive. Redox …

Acylation Of Glucosaminyl Phosphatidylinositol Revisited. Palmitoyl-Coa Dependent Palmitoylation Of The Inositol Residue Of A Synthetic Dioctanoyl Glucosaminyl Phosphatidylinositol By Hamster Membranes Permits Efficient Mannosylation Of The Glucosamine Residue, William T. Doerrler, Jianhua Ye, J. R. Falck, Mark A. Lehrman

Faculty Publications

Two critical steps in the assembly of yeast and mammalian glycosylphosphatidylinositol (GPI) anchor precursors are palmitoylation of the inositol residue and mannosylation of the glucosamine residue of the glucosaminyl phosphatidylinositol (GlcNα-PI) intermediate. Palmitoylation has been reported to be acyl-CoA dependent in yeast membranes (Costello, L. C., and Orlean, P. (1992) J. Biol. Chem. 267, 8599-8603) but strictly acyl- CoA independent in rodent membranes (Stevens, V. L., and Zhang, H. (1994) J. Biol. Chem. 269, 31397-31403), and thus poorly conserved. In addition, it was suggested that acylation must precede mannosylation in both yeast (Costello, L. C., and Orlean, P. (1992) J. …

Nonequilibrium Critical Dynamics Of A Three Species Monomer-Monomer Model, Kevin E. Bassler, Dana A. Browne

Faculty Publications

We study a three species monomer-monomer catalytic surface reaction model with a reactive steady state bordered by three equivalent unreactive phases where the surface is saturated with one species. The transition from the reactive to a saturated phase shows directed percolation critical behavior. Each pair of these reactive-saturated phase boundaries joins at a bicritical point where the universal behavior is in the even branching annihilating random walk class. We find the crossover exponent from bicritical to critical behavior and a new exponent associated with the bicritical interface dynamics. © 1996 The American Physical Society.

Louisiana Agriculture Magazine, Fall 1996, Lsu Agricultural Experiment Station

Louisiana Agriculture

No abstract provided.

Theory And Operation Of Continuous Flow Systems For The Study Of Benthic-Pelagic Coupling, Tina Miller-Way, Robert R. Twilley

Faculty Publications

Continuous flow systems have not been widely used in the study of benthic-pelagic coupling in marine systems. This paper discusses the theoretical and practical use of continuous flow sysrems for the study of benthic exchange processes and presents the results of experiments which compared continuous flow (open) and closed (batch) systems and investigated the sensitivity of exchange rates to residence times in a continuous flow system. Continuous flow systems minimize the problem of environmental dependency of benthic-pelagic exchange rates by maintaining initial experimental conditions throughout an incubation. However, the selection of a supply rate (i.e. residence time) is critical in …

Glutathione-Mediated Destabilization In Vitro Of [2fe-2s] Centers In The Soxr Regulatory Protein, Huangen Ding, Bruce Demple

Faculty Publications

SoxR is a transcription factor that governs a global defense against the oxidative stress caused by nitric oxide or excess superoxide in Escherichia coli. SoxR is a homodimer containing a pair of [2Fe-2S] clusters essential for its transcriptional activity, and changes in the stability of these metal centers could contribute to the activation or inactivation of SoxR in vivo. Herein we show that reduced glutathione (GSH) in aerobic solution disrupts the SoxR [2Fe-2S] clusters, releasing Fe from the protein and eliminating SoxR transcriptional activity. This disassembly process evidently involves oxygen-derived free radicals. The loss of [2Fe-2S] clusters does not occur …

Hydrocarbon Degradation In Louisiana's Salt And Fresh Water Marshes: Inherent Potential, Enhancement, And In-Situ Monitoring Techniques, William A. Jackson

LSU Historical Dissertations and Theses

The ability to effectively remediate crude oil from marsh systems is important due to the coexistence of the economically important hydrocarbon industry and ecologically and economically valuable marshes. Laboratory and field studies were initiated to examine the intrinsic ability of coastal marshes to biodegrade crude oil, to determine the ability to enhance degradation using nutrient additions, and develop a superior monitoring technique. The alkane and poly aromatic hydrocarbon (PAH) fractions seem to be independently degraded and these systems appear to have much greater capacity to degrade PAHs than alkanes. Nitrogen was found to be a limiting factor for both alkane …

Effects Of Climate Change On Hypoxia In Coastal Waters: A Doubled Co2 Scenario For The Northern Gulf Of Mexico, Dubravko Justic, Nancy N. Rabalais, R. Eugene Turner

Faculty Publications

Projections of general circulation models suggest that freshwater discharge from the Mississippi River to the coastal ocean will increase 20% if atmospheric CO2 concentration doubles. This result is likely to affect water column stability, surface productivity, and global oxygen cycling in the northern Gulf of Mexico, which is the site of the largest (up to 16,500 km2) and most severe hypoxic zone (liter‒1) in the western Atlantic Ocean. We use a coupled physical-biological two-box model to investigate potential effects of climate change on seasonal oxygen cycling and hypoxia in river-dominated coastal waters. The model was developed and calibrated using comprehensive …

Louisiana Agriculture Magazine, Summer 1996, Lsu Agricultural Experiment Station

Louisiana Agriculture

No abstract provided.

Response Of Sedimentary Bacteria In A Louisiana Salt Marsh To Contamination By Diesel Fuel, Kevin R. Carman, Jay C. Means, Steven C. Pomarico

Faculty Publications

In a 28 d microcosm study, we examined the effects of diesel-contaminated sediment on the sedimentary bacterial community of a Louisiana (USA) salt marsh that has been chronically exposed to petroleum hydrocarbons for decades. Diesel contaminants in microcosms as determined from polycyclic aromatic hydrocarbon (PAH) concentration ranged from 0.55 to 55 ppm (dry weight). Bacterial metabolism (incorporation of 14C-acetate and 3H-leucine) and bacterial abundance were not affected by diesel-contaminated sediment at any concentration. Bacterial degradation of 14C-phenanthrene, however, increased in direct proportion to the amount of diesel- contaminated sediment added. Ambient sediment also exhibited significant capacity to degrade PAH. The …

Nutrient Changes In The Mississippi River And System Responses On The Adjacent Continental Shelf, Nancy N. Rabalais, R. Eugene Turner, Dubravko Justic, Quay Dortch, William J. Wiseman, Barun Sen Gupta

Faculty Publications

The Mississippi River system ranks among the world's top 10 rivers in freshwater and sediment inputs to the coastal ocean. The river contributes 90% of the freshwater loading to the Gulf of Mexico, and terminates amidst one of the United States' most productive fisheries regions and the location of the largest zone of hypoxia, in the western Atlantic Ocean. Significant increases in riverine nutrient concentrations and loadings of nitrate and phosphorus and decreases in silicate have occurred this century, and have accelerated since 1950. Consequently, major alterations have occurred in the probable nutrient limitation and overall stoichiometric nutrient balance in …

The Expression And Regulation Of Stats During 3t3-L1 Adipocyte Differentiation, Jacqueline M. Stephens, Ron F. Morrison, Paul F. Pilch

Faculty Publications

STATs (Signal Transducers and Activators of Transcription) comprise a family of transcription factors that reside in the cytoplasm of resting cells. In response to a variety of stimuli, STATs become tyrosine- phosphorylated and translocate to the nucleus where they mediate transcriptional regulation. We have used the 3T3-L1 murine cell line to examine the expression of STAT proteins as a function of their differentiation into adipocytes. The expression of STATs 1, 3, and 5, but not of STAT 6, is markedly elevated in adipocytes as compared with their fibroblast precursors. Exposure of 3T3-L1 preadipocytes to tumor necrosis factor α (TNFα) blocks …

Impact Of The Soft-Shell Clam Mya Arenaria On Sulfate Reduction In An Intertidal Sediment, Kim Hansen, Gary M. King, Erik Kristensen

Faculty Publications

Sulfate reduction and various parameters related to the sulfur cycle were examined at mm to cm scales around burrows of the soft-shell clam Mya arenaria in an intertidal sediment (Lowes Cove, Maine, USA). Sulfate reduction rates were 1.5 to 2 times higher in the inner 1 to 5 mm region surrounding the burrow than in ambient sediment In contrast, pools of reduced sulfur increased with the distance from the burrow wall to values ≈1.5 times higher in ambient sediment. The highest numbers of sulfate-reducing bacteria (estimated using a most-probable-number technique) and microbial biomass (estimated from phospholipid phosphorous content) relative to …

Urea Production And Turnover Following The Addition Of Amp, Cmp, Rna And A Protein Mixture To A Marine Sediment, Mette S. Therkildsen, Gary M. King, Bente Aa Lomstein

Faculty Publications

The potential of adenosine 5′-monophosphate (AMP), cytidine 5′-monophosphate (CMP), 16S ribosomal RNA, and a protein (bovine serum albumin) to serve as substrates for bacterial urea production was evaluated in a defaunated, anoxic marine sediment. AMP, CMP and RNA stimulated urea production and urea turnover, but CMP to a lesser degree than AMP and RNA. The increase in urea production and turnover rates took place immediately after AMP, CMP, and RNA were added to the sediment. The rapid response in urea production and turnover rates suggests that the necessary uptake mechanisms and enzymes to utilize the substrates were present constitutively. Addition …

Solution Conformation Of De Novo Antimicrobial Peptides, Maryam Javadpour

LSU Historical Dissertations and Theses

De novo antimicrobial peptides were designed to help study the necessary conformational properties of biologically active peptides. One set of peptides are: (KLAKKLA)n, (KLAKLAK)n, (n=l, 2, 3), (KALKALK)3, (KLGKKLG)n, and (KAAKKAA)n (n=2,3), while the second set have phenylalanine substituted for leucine, (KFAKFAK)3 and (KFAKKFA)n, (n=3,4). These peptides were designed. to be perfectly amphipathic in helical conformations.

Circular dichroism was used to study their secondary structure in aqueous solution, sodium dodecylsulfate micelles, and phospholipid vesicles. Peptide antibacterial activity was tested against E. coli, P. aeruginosa, and S. aureus. Peptide cytotoxicity was tested against a mammalian cell line, 3T3 mouse fibroblasts. Our …

Dna Sequences Of Alu Elements Indicate A Recent Replacement Of The Human Autosomal Genetic Complement, Alec Knight, Mark A. Batzer, Mark Stoneking, Hemant K. Tiwari, W. Douglas Scheer, Rene J. Herrera, Prescott L. Deininger

Faculty Publications

DNA sequences of neutral nuclear autosomal loci, compared across diverse human populations, provide a previously untapped perspective into the mode and tempo of the emergence of modern humans and a critical comparison with published clonally inherited mitochondrial DNA and Y chromosome measurements of human diversity. We obtained over 55 kilobases of sequence from three autosomal loci encompassing Alu repeats for representatives of diverse human populations as well as orthologous sequences for other hominoid species at one of these loci. Nucleotide diversity was exceedingly low. Most individuals and populations were identical. Only a single nucleotide difference distinguished presumed ancestral alleles from …

Lumières, Spring 1996, Louisiana State University And Agricultural & Mechanical College

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