View All Items

Title: Discovery and investigation of survivin-targeting marine natural products from Ellisella paraplexauroides and Eudistoma olivaceum.
Creator: Francis, Kirstie Tandberg, Wright, Amy E., Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
Abstract/Description: In 2020, the National Institute of Health reported that more than 1.8 million people in the U.S. were diagnosed with cancer and over half a million died from those diseases. There is an urgent need for innovative and effective new treatments which stem from novel cancer drug targets. Survivin, the smallest member of the inhibitor of apoptosis protein (IAP) family, is highly expressed during development and in cancer cells but not in differentiated tissues, making it a tumor-selective target...
Show moreIn 2020, the National Institute of Health reported that more than 1.8 million people in the U.S. were diagnosed with cancer and over half a million died from those diseases. There is an urgent need for innovative and effective new treatments which stem from novel cancer drug targets. Survivin, the smallest member of the inhibitor of apoptosis protein (IAP) family, is highly expressed during development and in cancer cells but not in differentiated tissues, making it a tumor-selective target for new drug therapies. At only 16.5 kDa, it consists of a single Baculovirus IAP Repeat (BIR) domain and an α-helical coiled coil. Survivin plays a multitude of roles in the growth and survival of cancer cells—which can be attributed to the variable cellular localizations and posttranslational modifications of the protein—including inhibition of apoptosis, mitosis and cell cycle progression, DNA damage repair, drug resistance, metastasis, angiogenesis, and cell senescence, among others. A drug that is able to target surviving transcription or posttranslational modification or disrupt one of these critical pathways may serve as an attractive new cancer therapy. Despite decades of research on surviving and its intracellular functions, researchers have yet to find an FDA approved drug. Using a high throughput approach, Harbor Branch Oceanographic Institute’s chemical library of marine natural products was screened by the Guzmán lab to identify compounds capable of downregulating survivin expression in A549 non-small cell lung carcinoma and DLD-1 colorectal adenocarcinoma cell lines. From the screening assay, pure compounds were identified which reduce levels of survivin protein in cancer cells. Chapter 2 describes the isolation and structure elucidation of five polyhydroxylated sterol analogs from Ellisella paraplexauroides, four of them novel. Chapter 3 describes the isolation and structure elucidation of two compounds from Eudistoma olivaceum, eudistomin H and I. Chapter 4 describes the secondary biological testing employed to determine if the reduction of survivin expression was driven by reducing de novo production or increasing the degradation of existing protein by evaluating differential gene expression of survivin mRNA using reverse transcriptase quantitative polymerase chain reaction and measuring degradation rates of survivin protein, respectively.
Show less
Date Issued: 2021
PURL: http://purl.flvc.org/fau/fd/FA00013828
Subject Headings: Survivin, Marine natural products, Antineoplastic agents--Development
Format: Document (PDF)

Title: Discovery and structural characterization of conotoxins from the venom of vermivorous cone snails.
Creator: Dovell, Sanaz., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Cone snails are venomous marine gastropods that produce venom rich in neuroactive peptides, called conopeptides. The majority of published work on conopeptides has been from fish-hunting and mollusk-hunting cone snails. The work in this dissertation focuses on the discovery and characterization of novel conopeptides from the venom of worm-hunting cone snails. Eleven novel conopeptides have been isolated and biochemically characterized from the venom of C. nux using high performance liquid...
Show moreCone snails are venomous marine gastropods that produce venom rich in neuroactive peptides, called conopeptides. The majority of published work on conopeptides has been from fish-hunting and mollusk-hunting cone snails. The work in this dissertation focuses on the discovery and characterization of novel conopeptides from the venom of worm-hunting cone snails. Eleven novel conopeptides have been isolated and biochemically characterized from the venom of C. nux using high performance liquid chromatography for the isolation and purification, and mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy were used for the biochemical characterization of the conopeptides. Nano-NMR spectroscopy was used as a tool to elucidate the three-dimensional structures of four conotoxins using native quantities of peptide isolated from the venom of C. nux, C. villepinii, and C. regius. In addition, the sequence-specific assignments and molecular model of a conotoxin from the venom of C. flo ridanus was also completed. The first chapter reviews the known conotoxin three-dimensional structures and cystine-constrained frameworks. The second chapter presents the mini-M conotoxins isolated from the venom of C. nux. The third chapter presents the three-dimensional NMR solution structure of a mini-M conotoxin from the venom of C. regius. The fourth chapter presents the cysteine-free conopeptides isolated from the venom of C. nux; conorfamide-nux1, a RFamide-related peptide, and nux770, a short pentapeptide. The fifth chapter presents the T-superfamily conotoxins isolated from the venom of C. nux, as well as the three-dimensional solution structure of one of the T-superfamily conotoxins. The sixth chapter presents the NMR solution structure of the first conotoxin with a cysteine-stabilized helix-loop-helix fold., Finally, the seventh chapter presents the O-superfamily conotoxins isolated from the venom of C. nux, as well as the three-dimensional solution structure of one of the O- superfamily conotoxins with an unusually knotted fold. This work shows the vast structural diversity of peptides that cone snails continue to engineer.
Show less
Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2684305
Subject Headings: Gastropoda, Venom, Peptides, Structure, Conus, Venom
Format: Document (PDF)

Title: DISSECTING THE MECHANISTIC ROLES OF REGULATORS IN MEDIATING AMYLOID-BETA AMYLOIDOGENESIS.
Creator: Shen, Fengyun, Du, Deguo, Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
Abstract/Description: Alzheimer’s disease (AD) is a common neurodegenerative disorder. The most recognized disease pathology is the Amyloid-β (Aβ) cascade hypothesis which states that the accumulation of Aβ plaques might be the cause of AD. In the AD brain, Aβ plaques stockpile a variety of molecular components including metals, lipids, nucleic acids, carbohydrates, and peptides, indicating Aβ aggregation might be influenced by these modulators. In this dissertation, we investigated the effects of Zn2+ and...
Show moreAlzheimer’s disease (AD) is a common neurodegenerative disorder. The most recognized disease pathology is the Amyloid-β (Aβ) cascade hypothesis which states that the accumulation of Aβ plaques might be the cause of AD. In the AD brain, Aβ plaques stockpile a variety of molecular components including metals, lipids, nucleic acids, carbohydrates, and peptides, indicating Aβ aggregation might be influenced by these modulators. In this dissertation, we investigated the effects of Zn2+ and carnosine, phospholipids, and β-hairpins on Aβ aggregation to dissect their mechanistic roles in the amyloidogenesis of Aβ. We first systematically studied the kinetic impact of Zn2+ on the aggregation of Aβ40 and Aβ40-M. Our results show that the presence of Zn2+ transforms the Aβ40 aggregation kinetics from a single sigmoidal to a biphasic process, while the aggregation of Aβ40-M is significantly suppressed by Zn2+. We also found that a nature dipeptide, carnosine, remarkably decreases the activity of Zn2+ on modulating Aβ aggregation, although it has a weak direct effect on the peptide aggregation kinetics. Second, we investigated the activities of Aβ40 and Aβ42 in inducing membrane damage and the effects of lipid membranes on the aggregation of these peptides using liposome models containing mitochondrial-specific phospholipid–cardiolipin (CL).
Show less
Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014314
Subject Headings: Alzheimer's disease, Amyloid beta-Peptides, Neurodegenerative Diseases
Format: Document (PDF)

Title: Diterpene biosynthesis in early ontogenetic stages of Pseudopterogorgia elisabethae and Pseudopterogorgia bipinnata.
Creator: Mukherjee, Maia Stapleton, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: There is growing evidence that secondary metabolites isolated from some marine invertebrates may actually be produced by a symbiont. The capacity of early ontogenetic stages of Pseudopterogorgia elisabethae and Pseudopterogorgia bipinnata to biosynthesize biologically active and pharmaceutically important diterpenes was examined. These early life stages lack the algal symbionts found in adult colonies of the species, thus removing one level of complexity. The larvae and polyps of these two...
Show moreThere is growing evidence that secondary metabolites isolated from some marine invertebrates may actually be produced by a symbiont. The capacity of early ontogenetic stages of Pseudopterogorgia elisabethae and Pseudopterogorgia bipinnata to biosynthesize biologically active and pharmaceutically important diterpenes was examined. These early life stages lack the algal symbionts found in adult colonies of the species, thus removing one level of complexity. The larvae and polyps of these two species produced high concentrations of the diterpenoid secondary metabolites, one of which proved to significantly deter fish-feeding in in situ feeding assays. Additionally, a novel cembrenoid diterpene was isolated from P. bipinnata. The structure of this compound, bipinnatolide L (40) was solved using 1D and 2D NMR experiments.
Show less
Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13297
Subject Headings: Chemistry, Biochemistry
Format: Document (PDF)

Title: An ecological study of photoautotrophs in Lake Worth.
Creator: Bolter, Keren P., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Little Lake Worth (LLW) (800 m x 200 m x 8« m) is an artificially deep, monomictic marine basin. Pigments and other water quality parameters (O2, pH, T, S, NO3 -. etc.) were utilized to characterize phototrophic communities and water quality. The water column is dominated by diatoms except in the hypolimnon during stratification events (late Summer) when strong anoxia and H2S favors abundant Chlorobium sulfur bacteria. Results indicate nitrate-enriched freshwater baseflow indicative of septic...
Show moreLittle Lake Worth (LLW) (800 m x 200 m x 8« m) is an artificially deep, monomictic marine basin. Pigments and other water quality parameters (O2, pH, T, S, NO3 -. etc.) were utilized to characterize phototrophic communities and water quality. The water column is dominated by diatoms except in the hypolimnon during stratification events (late Summer) when strong anoxia and H2S favors abundant Chlorobium sulfur bacteria. Results indicate nitrate-enriched freshwater baseflow indicative of septic tank seepage during the wet season. This also appears to lead to the accumulation of concentrated organic matter in the sediment. LLW is a potential threat to the health of the ecosystem and the humans using it recreationally. More research is required to verify the effectiveness of restoration options. The spatial and temporal distribution of Chlorobium (phaeovibiroides tent.) and their Bacteriochlorophyll-e homologues is described and compared to similar studies.
Show less
Date Issued: 2010
PURL: http://purl.flvc.org/FAU/3151675
Subject Headings: Algae culture, Water quality, Biotic communities, Marine sediments
Format: Document (PDF)

Title: Effect of external pH on cyanobacterial pigment expression.
Creator: West, Maria., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Cyanobacteria are classified as alkalophiles despite their preferential uptake of the acidic form of dissolved inorganic carbon. Long term impacts of external pH on the expression of photosynthetic and structural pigments in Schizothrix calcicola were investigated as potential contributing factors to this phenomenon. More robust cell walls in S. calcicola at pH
Show moreCyanobacteria are classified as alkalophiles despite their preferential uptake of the acidic form of dissolved inorganic carbon. Long term impacts of external pH on the expression of photosynthetic and structural pigments in Schizothrix calcicola were investigated as potential contributing factors to this phenomenon. More robust cell walls in S. calcicola at pH <7 are suggested by significantly greater expression of myxoxanthophylls. Direct and indirect physiological costs of altering cell walls may contribute to S. calcicola's depressed growth at acidic pH. Comparison of chlorophylls expression suggests that alkaline rather than neutral external pH is only beneficial for S. calcicola growth in absence of nutrient limitation. While the cyanobacterial biomarker ratio of chlorophylls to echinenone was stable across the pertinent pH range of 6-8, other pigment ratios in S. calcicola were affected by pH with an approximately two week lag between the change of pH and the corresponding change of pigment expression.
Show less
Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2795335
Subject Headings: Environmental toxicology, Cyanobacteria, Environmental aspects, Ecosystem management, Vegetation dynamics
Format: Document (PDF)

Title: Effects of Carbon Dioxide Levels on Growth and Pigments of Freshwater Algae.
Creator: Bermudez, Jeanne, Louda, J. W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: This project was designed to investigate the effects of carbon dioxide (CO2) levels on the growth and pigment ratios (chemotaxonomy) of freshwater algal species typical to the south Florida surface waters. Green algae, diatoms, and cyanobacteria were cultured under 400 or 800 ppm CO3 in air for several weeks. Growth monitoring used a cell counter, hemocytometer, and chlorophyll fluorescence. Pigments were analyzed using HPLC-PDA. Experiments with certified CO2 concentrations (400, 600, 800,...
Show moreThis project was designed to investigate the effects of carbon dioxide (CO2) levels on the growth and pigment ratios (chemotaxonomy) of freshwater algal species typical to the south Florida surface waters. Green algae, diatoms, and cyanobacteria were cultured under 400 or 800 ppm CO3 in air for several weeks. Growth monitoring used a cell counter, hemocytometer, and chlorophyll fluorescence. Pigments were analyzed using HPLC-PDA. Experiments with certified CO2 concentrations (400, 600, 800, 1200 ppm) were conducted with helium degassed ultrapure water and each of three culture media. Theoretical and experimental pH values with water matched exactly. However, each culture media proved to exhibit significant buffer capacity. Cell growth monitoring was problematic except for the cyanobacterium Microcystis aeruginosa. That species responded to increased CO2 (800 ppm) with increased growth rates as predicted. The other species gave erratic results mainly due to difficulties in obtaining valid consistent cell counts.
Show less
Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013170
Subject Headings: Freshwater algae--Growth, Chemotaxonomy, Carbon dioxide, Pigments (Biology)
Format: Document (PDF)

Title: Effects of glycosylation on melanoma interactions with type IV collagen models.
Creator: Aukszi, Beatrix., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Tumor cells interact with basement membrane collagen at the site of extravasation through distinct cellular receptors, including the α2β1 and α3β1integrins. These receptors are known to be differentially expressed in metastatic tumors, relative to the normal cells, depending on tumor type and stage of progression. The binding sites within type IV collagen for the α2β1 andα3β1 integrins have been identified. Since both of the integinspecific sequences possess at least one glycosylated Hyl...
Show moreTumor cells interact with basement membrane collagen at the site of extravasation through distinct cellular receptors, including the α2β1 and α3β1integrins. These receptors are known to be differentially expressed in metastatic tumors, relative to the normal cells, depending on tumor type and stage of progression. The binding sites within type IV collagen for the α2β1 andα3β1 integrins have been identified. Since both of the integinspecific sequences possess at least one glycosylated Hyl residue, we questioned whether glycosylation could modulate integrin binding. Triple-helical peptides with and without Lys substituted by glycosylated Hyl for Lys543 and Lys540 from the human a1(IV)531-543 gene sequence (α3β integrin-specific) and Lys393 from the human a1(IV)382-393 gene sequence (α2β1 integrin-specific) were synthesized and utilized in the present study., Cellular response to these triple helical ligands was tested with a primary melanoma cell line, WM-115, and three highly metastatic melanoma cell lines , WM-266-4, M14#5, and SK-MEL-2. Cell adhesion and cell spreading assays yielded differing results depending on whether the ligands contained glycosylated Hyl residues or not. In general, a decrease in cellular affinity toward the ligands was observed when glycosylated Hyl was present. Differences in the levels of adhesion and spreading between cell lines representing different stages of melanoma were also observed. Neutral B-galactosidase activity was detected in all four cell lines. Enzymatic activity levels were comparable for the three metastatic cell lines, whereas distinctively higher activity was detected for cells originating from a primary lesion. This acitivity can signal the potential of tumor cells to enhance and recover their invasive abilities., The ability of each cell line to remove the galactose from the peptide ligands has been investigated, to test whether tumor cells can reestablish binding relationships between the α2β1 and α3β1 integrins and type IV collagen that are reduced by glycosylation.
Show less
Date Issued: 2008
PURL: http://purl.flvc.org/FAU/186335
Subject Headings: Animal cell biotechnology, Combinatorial chemistry, Integrins, Research, Methodology, Cell adhesion molecules, Physiological effect
Format: Document (PDF)

Title: Effects of small molecule modulators and Phospholipid Liposomes on βeta-amyloid (1-40) Amyloidogenesis.
Creator: Morris, Clifford, Du, Deguo, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Beta-Amyloid (1-40) (Aβ40) is an aggregation prone protein, which undergoes a nucleation-dependent aggregation process causing the pathological neurodegeneration by amyloid plaque formation implicated in Alzheimer’s disease. In this thesis, we investigated the effects of small molecule modulators extracted from the marine invertebrate Pseudopterogorgia elisabethae on the Aβ40 amyloidogenic process using in- vitro ThT fluorescence assay and atomic force microscopy. We also investigated the...
Show moreBeta-Amyloid (1-40) (Aβ40) is an aggregation prone protein, which undergoes a nucleation-dependent aggregation process causing the pathological neurodegeneration by amyloid plaque formation implicated in Alzheimer’s disease. In this thesis, we investigated the effects of small molecule modulators extracted from the marine invertebrate Pseudopterogorgia elisabethae on the Aβ40 amyloidogenic process using in- vitro ThT fluorescence assay and atomic force microscopy. We also investigated the effects of neutral and anionic phospholipid liposomes on Aβ40 aggregation. Our results show that a marine natural product Pseudopterosin-A and its derivatives can suppress and modulate the Aβ40 aggregation process. Furthermore, our results demonstrate that a neutral phospholipid liposome inhibits Aβ40 fibril formation, whereas the anionic liposomes promote it.
Show less
Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004453, http://purl.flvc.org/fau/fd/FA00004453
Subject Headings: Aggregation (Chemistry), Alzheimer's disease -- Pathogenesis, Alzheimer's disease -- Research, Amyloid beta protein, Molecular biology, Molecular dynamics, Prions, Proteins -- Metabolism -- Disorders
Format: Document (PDF)

Title: ELECTROCATALYTIC REACTIONS OF OXO ANIONS WITH MOLYBDENUM - CATECHOL COMPLEXES.
Creator: LAHR, SUZANNE KAY, Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Catalytic reductions of NO2, ClO3, and BrO3 by aqueous molybdenum-catechol complexes at pH 9 are investigated by electrochemical techniques. Binding of substrate to the molybdenum center occurs through the unshared electron pair of the substrate central atom. The molybdenum (V) and - (IV) oxidation states are catalytically active, while Mo(III) is not. A single mechanism for the reaction of Mo(V) with all three substrates is proposed, and a rate expression for this reaction is derived....
Show moreCatalytic reductions of NO2, ClO3, and BrO3 by aqueous molybdenum-catechol complexes at pH 9 are investigated by electrochemical techniques. Binding of substrate to the molybdenum center occurs through the unshared electron pair of the substrate central atom. The molybdenum (V) and - (IV) oxidation states are catalytically active, while Mo(III) is not. A single mechanism for the reaction of Mo(V) with all three substrates is proposed, and a rate expression for this reaction is derived. General features of the Mo (IV) reaction are describec. Nitrous oxide was identified by gas chromatography as a product of the Mo(V) - NO2 reaction.
Show less
Date Issued: 1982
PURL: http://purl.flvc.org/fcla/dt/14118
Subject Headings: Molybdenum--Analysis, Catechol--Analysis
Format: Document (PDF)

Title: ELECTROCATALYTIC REDUCTION OF ACETYLENE BY MOLYBDENUM-CYSTEINE AND MOLYBDENUM-EDTA COMPLEXES.
Creator: LEAZENBEE, LOUIS O., Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Binuclear oxo- and sulfide-bridged Mo(V)-cysteine and Mo(V)-EDTA complexes are chosen as model compounds for nitrogenase enzyme. Both groups of complexes undergo electrochemical reduction in a single four- electron step to Mo(III) dimers. The reduced binuclear Mo (III) units dissociate into catalytically active species capable of reducing the nitrogenase substrate, acetylene. Ease of dissociation increases as oxygen is replaced by sulfur in the bridging unit. Electrocatalytic reduction...
Show moreBinuclear oxo- and sulfide-bridged Mo(V)-cysteine and Mo(V)-EDTA complexes are chosen as model compounds for nitrogenase enzyme. Both groups of complexes undergo electrochemical reduction in a single four- electron step to Mo(III) dimers. The reduced binuclear Mo (III) units dissociate into catalytically active species capable of reducing the nitrogenase substrate, acetylene. Ease of dissociation increases as oxygen is replaced by sulfur in the bridging unit. Electrocatalytic reduction products of acetylene consist primarily of C2H4 and C2H6 at low partial pressures, but C4H6, C4H8, and higher hydrocarbons predominate at higher pressures. The reduction of substrate is believed to occur by a Mo(III) catalyst adsorbed on the electrode surface. A mechanism is proposed for the e lectrocatalysis, and its relationship to the enzymic catalysis is discussed.
Show less
Date Issued: 1977
PURL: http://purl.flvc.org/fcla/dt/13880
Subject Headings: Electrochemical analysis, Enzymatic analysis
Format: Document (PDF)

Title: ELECTROCHEMICALLY CATALYZED REDUCTION OF ACETYLENE BY A MOLYBDENUM - CYSTEINE COMPLEX.
Creator: LEDWITH, DEBRA ANN, Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The binuclear , di-mju-oxo-bridged molybdenum(V)-cysteine complex, Na2Mo2O4(cys)2, is frequently cited as a chemical model for nitrogenase enzyme. Coulometric reduction of Na2Mo2O4(cys)2 at the potential of Mo(V)--> Mo(III) reduction (-1. 35 to -1.50 V vs. SCE) in the presence o£ the nitrogenase substrate, acetylene, produces ethylene and ethane. Reduction of C2H2 does not occur in the absence of the molybdenumcysteine complex. The quantities of C2H4 and C2H6 produced are greater than the...
Show moreThe binuclear , di-mju-oxo-bridged molybdenum(V)-cysteine complex, Na2Mo2O4(cys)2, is frequently cited as a chemical model for nitrogenase enzyme. Coulometric reduction of Na2Mo2O4(cys)2 at the potential of Mo(V)--> Mo(III) reduction (-1. 35 to -1.50 V vs. SCE) in the presence o£ the nitrogenase substrate, acetylene, produces ethylene and ethane. Reduction of C2H2 does not occur in the absence of the molybdenumcysteine complex. The quantities of C2H4 and C2H6 produced are greater than the stoichiometric molybdenum content, hence the reduction is catalytic. Acetylene reduction is accompanied by catalytic hydrogen evolution at the surface of the mercury electrode. The rate of acetylene reduction and product yields vary with pH, applied electrode potential, concentration of Na2Mo2O4(cys)2, and the buffer salt. A mechanism for the catalytic process is proposed, and its relationship to chemical models for nitrogenase enzyme is discussed.
Show less
Date Issued: 1975
PURL: http://purl.flvc.org/fcla/dt/13732
Subject Headings: Acetylene reduction assay, Molybdenum
Format: Document (PDF)

Title: ELECTROCHEMISTRY OF MONOMERIC MOLYBDENUM (VI)-, (V)-, (IV)- AND (III)- CATECHOL COMPLEXES IN AQUEOUS MEDIA.
Creator: CHARNEY, LYNN MARLENE., Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The electrochemical reduction of the cis-dioxo Mo(VI)-catechol complex, MoO2(cat2^2-, is investigated at a mercury electrode in pH 3.5-10 aqueous buffers utilizing the techniques of cyclic voltammetry and controlled potential coulometry. The reduction of MoO2(cat2^2- proceeds by successive two-proton, one-electron and two- proton, two-electron transfer steps which produce monomeric Mo(V) and Mo(III) species. At pH 3.5-7 the Mo(V) monomer is unstable and undergoes dimerization. The mechanism...
Show moreThe electrochemical reduction of the cis-dioxo Mo(VI)-catechol complex, MoO2(cat2^2-, is investigated at a mercury electrode in pH 3.5-10 aqueous buffers utilizing the techniques of cyclic voltammetry and controlled potential coulometry. The reduction of MoO2(cat2^2- proceeds by successive two-proton, one-electron and two- proton, two-electron transfer steps which produce monomeric Mo(V) and Mo(III) species. At pH 3.5-7 the Mo(V) monomer is unstable and undergoes dimerization. The mechanism of the dimerization reaction and the structure of the Mo(V) dimer produced are determined. At pH 7-10 the monomeric Mo (V) and 2- Mo(III) complexes produced by reduction of MoO2(cat2^2- are stable. A stable Mo(IV) species is obtained upon reoxidation of the Mo( III ) monomer. The epr spectrum of the monomeric Mo(V) complex and visible spectra of all oxidation states in alkaline solution arc reported.
Show less
Date Issued: 1979
PURL: http://purl.flvc.org/fcla/dt/13979
Subject Headings: Electrochemistry
Format: Document (PDF)

Title: The electronic structures of dimolybdenum compounds; detailed electronic absorption and electrochemical studies of dimolybdenum BAII complexes.
Creator: Shih, Keng-Yu., Florida Atlantic University, Baird, Donald M., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The complexes Mo2(OAc)3(BAII), where BAII is 1,3-bis(arylimino)isoindoline, have been synthesized. A detailed interpretation of their 1H-NMR spectra has been made. The structure of the bis(pyridylimino)isoindoline derivative has been determined by X-ray analysis to facilitate the assignment of the resonance lines in the spectra. It has been found that there are trends in energies and intensities of the delta-->delta* transition in these compounds. Electron withdrawing substituents on the...
Show moreThe complexes Mo2(OAc)3(BAII), where BAII is 1,3-bis(arylimino)isoindoline, have been synthesized. A detailed interpretation of their 1H-NMR spectra has been made. The structure of the bis(pyridylimino)isoindoline derivative has been determined by X-ray analysis to facilitate the assignment of the resonance lines in the spectra. It has been found that there are trends in energies and intensities of the delta-->delta* transition in these compounds. Electron withdrawing substituents on the aromatic nitrogen heterocycles in BAII shift the delta-->delta* transition to a lower energy and a higher intensity as compared to electron releasing substituents. These trends suggest that mixing of M-->L charge transfer transitions with the delta-->delta* transitions is occurring in these compounds which is consistent with the results of electrochemical trends in oxidation potentials. The complexes which are hardest to oxidize in general have the lowest delta-->delta* transition.
Show less
Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14516
Subject Headings: Chemistry, Inorganic
Format: Document (PDF)

Title: Exploration of Methods to Identify Biosynthetic Genes and the Origin of Biosynthesis in Marine Octocorals.
Creator: Ranzer, Llanie Karen, Florida Atlantic University, Kerr, Russell G., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The overall goal of this research was to isolate key genes involved in the diterpene biosynthesis from Euniceafusca and Erythropodium caribaeorum using molecular biology techniques. The initial goal was to use fuscol induced cell cultures of Symbiodinium sp. isolated from E. fusca and to develop an approach based on differential display of mRNA-reverse transcription-PeR. Together with inverse PCR, these techniques ultimately provided a full-length farnesyl diphosphate synthase sequence....
Show moreThe overall goal of this research was to isolate key genes involved in the diterpene biosynthesis from Euniceafusca and Erythropodium caribaeorum using molecular biology techniques. The initial goal was to use fuscol induced cell cultures of Symbiodinium sp. isolated from E. fusca and to develop an approach based on differential display of mRNA-reverse transcription-PeR. Together with inverse PCR, these techniques ultimately provided a full-length farnesyl diphosphate synthase sequence. Functional expression of this enzyme was demonstrated with the addition of appropriate substrates and confirmed by chromatography. From this data, degenerate primer based PCR was used to isolate putative geranylgeranyl diphosphate biosynthetic genes from E. caribaeorum. Both chemical and genetic examinations of Pseudopterogorgia elisabethae eggs and their associated Symbiodinium sp. were employed to identify the biosynthetic origin of their diterpenes. Terpene content and biosynthetic capabilities of azooxanthellae eggs demonstrated the presence of pseudopterosins but also indicated that the eggs were not capable of producing these compounds. Likewise, no correlation could be observed for the phylogenetic relationships inferred for the Symbiodinium sp., with that of the terpene chemistry present in P. elisabethae. This finding leads us to speculate about an additional source of terpene production within this coral. Based on these and other recent findings suggesting symbiotic bacteria as the source of secondary metabolites from marine invertebrates, bacterial assemblages from E. caribaeorum were examined. This study revealed considerable phylogenetic bacterial diversity within this coral and the identification of several bacteria known to produce terpenes in other organisms.
Show less
Date Issued: 2006
PURL: http://purl.flvc.org/fau/fd/FA00000874
Subject Headings: Coral reef ecology, Diterpenes, Biosynthesis, Terpenes--Synthesis
Format: Document (PDF)

Title: An extraction optimization and determination of the absolute configuartion of clathric acid.
Creator: Rueda de Leon, Rolando, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Current research in natural products has heavily focused on the identification of potent biologically active compounds, specifically for drug development. The project detailed in this thesis focuses on the extraction of compounds from marine invertebrates as well as defining the absolute configuration for a compound. Utilizing marine invertebrates, the sonications method developed in this thesis provides an alternative approach to rapidly extract compounds for primary screening. This method...
Show moreCurrent research in natural products has heavily focused on the identification of potent biologically active compounds, specifically for drug development. The project detailed in this thesis focuses on the extraction of compounds from marine invertebrates as well as defining the absolute configuration for a compound. Utilizing marine invertebrates, the sonications method developed in this thesis provides an alternative approach to rapidly extract compounds for primary screening. This method is viable compared to a traditional overnight extraction method, without suffering compound degredation... Previously, clathric acid was isolated from an unknown Clathria sp. This compound is a bibyblic C-21 terpenoid shown to have mild antimicrobial activity against gram positive bacteria. With only its relative configuration established, additional amounts of clathric acid were required to define the overall absolute configuration. Identifying the Clathria sp. to be Clathria compressa, through spicule analysis, additional sponge tissues were then collected off the coast of Boca Raton, Florida to isolate additional quatities of clathric acid. The absolulte configuration was determined through circular dichroism and the octant rule to establish a final configuration for clathric acid's four carbon stereocenters to be: (3S, 7S, 8R, and 12S).
Show less
Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3355874
Subject Headings: Organic compounds, Analysis, Extraction (Chemistry), Natural products, Therapeutic use, Marine biotechology, Marine resources, Research, Sponges, Ecology
Format: Document (PDF)

Title: THE FORMATION OF DIHALOACETONITRILES BY CHLORINATION OF NATURAL WATER.
Creator: TREHY, MICHAEL LEE., Florida Atlantic University, Bieber, Theodore I., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Dihaloacetonitriles (DHANs) are shown to be produced by the chlorination of natural water, thus joining the ranks of the trihalomethanes (THMs) likewise produced by chlorination. Certain amino acids such as aspartic acid, tryptophan, and tyrosine are implicated as precursor substances for the DHANs and also to some extent for the THMs. The degradation of DHANs by hydrolysis and by thiosulfate was studied. Various methods of analysis are evaluated with respect to their ability to determine...
Show moreDihaloacetonitriles (DHANs) are shown to be produced by the chlorination of natural water, thus joining the ranks of the trihalomethanes (THMs) likewise produced by chlorination. Certain amino acids such as aspartic acid, tryptophan, and tyrosine are implicated as precursor substances for the DHANs and also to some extent for the THMs. The degradation of DHANs by hydrolysis and by thiosulfate was studied. Various methods of analysis are evaluated with respect to their ability to determine DHANs and THMs. The dilemma faced by water plants in dealing with the dual problem of DHANs and THMs is discussed. The role of hydrolysis in the formation of THMs has also been evaluated.
Show less
Date Issued: 1980
PURL: http://purl.flvc.org/fcla/dt/14011
Subject Headings: Water--Purification--Chlorination
Format: Document (PDF)

Title: GULF STREAM INTRUSIONS AS CONDUITS FOR LARVAL FISHES ALONG FLORIDA’S EAST COAST.
Creator: Woodward, Caroline, Chérubin, Laurent, Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
Abstract/Description: The mechanisms of larval fish transport have been rigorously studied in the past several decades, building foundational knowledge of key biological and environmental factors with which to inform decisions about species management. This study has been built upon information gained from previous studies to further elucidate the processes involved at the recruitment stage of larval fishes. Vertical swimming behaviors of larval fishes enable deliberate orientation within the water column to allow...
Show moreThe mechanisms of larval fish transport have been rigorously studied in the past several decades, building foundational knowledge of key biological and environmental factors with which to inform decisions about species management. This study has been built upon information gained from previous studies to further elucidate the processes involved at the recruitment stage of larval fishes. Vertical swimming behaviors of larval fishes enable deliberate orientation within the water column to allow organisms of limited mobility greater control over their horizontal movements. Vertical accumulation patterns of larvae are found to be tightly dependent on the strength of stratification within the water column at nursery entrances, such as estuaries. Onshore currents, such as upwelling and surface intrusions, are found to be conduits for entry into these systems. This study observed and analyzed the influence of intrusions by the Gulf Stream into the Fort Pierce Inlet and the vertical accumulation patterns of late-stage larvae associated with those events. This study incorporated a well-established zooplanktonic abundance sampling technique to achieve two primary goals: (1) to analyze the vertical abundances of larval fishes in stratified flow during Gulf Stream intrusions and (2) to assess the correlation between larval influx and intrusion events. The results of this study show a significant and positive correlation between propagule pressure of larval fishes and incidence of Gulf Stream intrusion events. Whereas previous studies have primarily described the spatiotemporal aspects of larval transport in a broader sense, our findings revealed a greater layer of complexity in the mechanisms of transport by incorporating localized hydrographic features. The information gleaned from these results can inform the ecological considerations of future fisheries management and study efforts via additional understanding about the role of physical oceanographic events in a critical life stage.
Show less
Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014263
Subject Headings: Gulf Stream (Fla.), Larvae--Dispersal, Fishes--Larvae
Format: Document (PDF)

Title: Hemisynthesis and Characterization of Cyclopheophorbides.
Creator: Mortezaei-Rad, Mitra, Florida Atlantic University, Louda, J. William, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Cyclopheophorbides absorb light at higher wavelengths (> 670 run) as compared to their precursor pyropheophorbides ( ~ 666 run) and are strong antioxidants. Therefore they could potentially be used as photosensitizers in photodynamic therapy, although this study does not focus on the pharmacology aspect of this class of compounds. The overall goal of this study was to hemisynthesize, purify and characterize certain cyclopheophorbides from both chlorophyll a and b families. The known...
Show moreCyclopheophorbides absorb light at higher wavelengths (> 670 run) as compared to their precursor pyropheophorbides ( ~ 666 run) and are strong antioxidants. Therefore they could potentially be used as photosensitizers in photodynamic therapy, although this study does not focus on the pharmacology aspect of this class of compounds. The overall goal of this study was to hemisynthesize, purify and characterize certain cyclopheophorbides from both chlorophyll a and b families. The known hemisynthesis of 13^2,17^3-cyclopheophorbide a enol was repeated. A major success in the purification process was achieved by utilizing polystyrene divinylbenzene (PS-DVB a.k .a. PRP-1 TM) as the stationary phase in reversed phase flash chromatography. Altering (TMS)2-NNa with (TMS)2-NLi was found to increase yields. 13^2,17^3 -mesocyclopheophorbide a enol was successfully hemisynthesized as a novel compound. Methyl-3-devinyl-3-[1-hexyloxy]ethyl pyropheophorbide a (HPPH-ME), was prepared, purified and molecular characteri zation on the compound was performed. Hemisynthesis ofHPPH-CYCLO from HPPH-ME was attempted, but was unsuccessful. Zinc and copper pyropheophorbide a methyl esters were prepared with the intent of forming of zinc and copper CYCLO. Hemisynthesis of corresponding metalloCYCLO from both insertion of the metal inside the CYCLO core and cyclizations of metal derivatives of pyropheophorbide a methyl ester were unsuccessful. Chlorophyll b was successfully extracted from green algae Chiarella and purified in mg lots (100%) utilizing RP-LPLC and with a binary solvent gradient program. Pheophorbide b methyl ester and pyropheophorbide b methyl ester were made and characterized. Hemisynthesis of CYCLO-b was unsuccessful likely due to the altered reactivity of pyropheophorbide b (vs. -a) methyl ester. To reduce the reactivity, reduction of formyl group of pyropheophorbide b methyl ester with NaBH4 was performed. Still, formation of a CYCLO derivative was not achieved. Chromatographic purification, mass and NMR characterization of CYCLO, mesoCYCLO, HPPH-ME and all precursor compounds are reported. 2D NMR of most of these compounds are reported here for the first time.
Show less
Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00000872
Subject Headings: High performance liquid chromatography, Organometallic chemistry, Organic compounds--Spectra, Organophosphorus compounds
Format: Document (PDF)

Title: High performance liquid chromatographic separation of sedimentary vanadyl porphyrins.
Creator: Huang, Xiaoxue, Florida Atlantic University, Baker, Earl W., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: A method of reversed phase HPLC gradient elution was developed and evaluated for the separation of vanadyl porphyrins. Separation was compared with the result of isocratic elution. It shows that gradient elution method is suitable for vanadyl porphyrin separation and better separation result can be obtained by gradient elution. Gradient elution improves the separation by changing the retention time of different components in the sample mixture and increases the difference of k' (capacity...
Show moreA method of reversed phase HPLC gradient elution was developed and evaluated for the separation of vanadyl porphyrins. Separation was compared with the result of isocratic elution. It shows that gradient elution method is suitable for vanadyl porphyrin separation and better separation result can be obtained by gradient elution. Gradient elution improves the separation by changing the retention time of different components in the sample mixture and increases the difference of k' (capacity factor). Vanadyl porphyrin samples Bakken 6362', Treibs #1 and Treibs #3 were analyzed by this method. Results correlate very well with the results of mass spectrometry analysis of these samples which have been done by some other workers.
Show less
Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/15094
Subject Headings: Porphyrins, High performance liquid chromatography
Format: Document (PDF)

FAU Theses and Dissertations (131)	+ -
FAU College Collections (7)	+ -

Peptides (10)	+ -
Synthesis (8)	+ -
Chemistry, Biochemistry (6)	+ -
Organic compounds (6)	+ -
Venom (6)	+ -

Alzheimer's disease (5)	+ -
Chemistry, Organic (5)	+ -
Organometallic polymers (5)	+ -
Amyloid (4)	+ -
Analysis (4)	+ -
Gastropoda (4)	+ -
Marine natural products (4)	+ -
Raman spectroscopy (4)	+ -
Research (4)	+ -
Structure (4)	+ -
Therapeutic use (4)	+ -
Amyloid beta-Peptides (3)	+ -
Cellular signal transduction (3)	+ -
Conus (3)	+ -
Coral reef ecology (3)	+ -
Ecology (3)	+ -
Environmental aspects (3)	+ -
Infrared spectroscopy (3)	+ -
Intermediates (Chemistry) (3)	+ -
Marine organisms (3)	+ -
Marine pharmacology (3)	+ -
Matrix Metalloproteinases (3)	+ -
Peptides -- Structure (3)	+ -
Prions (3)	+ -
Sponges (3)	+ -

Everglades (1)	+ -
Florida (1)	+ -
Lake Worth Lagoon (Fla.) (1)	+ -

Electronic Thesis or Dissertation (131)	+ -
Program Review (7)	+ -

Search In

Pages

Pages

Sort Results By:

Narrow results by:

Collection

Topical Subject

Geographic Subject

Genre

Type of Resource

Language

Creator

Format

Owner