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- Title
- New stereoselective reactions to form amido alkyl c-n and vinyl triflate c-o bonds via carbocation intermediates & ultrafast silicon fluorination methodologies for applications in pet imaging.
- Creator
- Alhuniti, Mohammed, Lepore, Salvatore D., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
We report here the development of a Lewis acid catalyzed method for the dehydrative coupling of cyclic alcohols and nitriles to form amides with retention of configuration. By contrast, the formation of amides by nitrile trapping of carbocations (Ritter reaction) usually affords racemic product. The present reaction was accomplished by first converting alcohol starting materials to their corresponding chlorosulfites in situ. Even after an extensive search, only copper (II) salts were able to...
Show moreWe report here the development of a Lewis acid catalyzed method for the dehydrative coupling of cyclic alcohols and nitriles to form amides with retention of configuration. By contrast, the formation of amides by nitrile trapping of carbocations (Ritter reaction) usually affords racemic product. The present reaction was accomplished by first converting alcohol starting materials to their corresponding chlorosulfites in situ. Even after an extensive search, only copper (II) salts were able to produce the desired conversion of these chlorosulfites to amides though with low catalytic turnover. Improving the turnover without deteriorating the stereochemical outcome was eventually accomplished by a careful selection of the reagent addition sequence and through the removal of gaseous byproducts. This Ritter-like coupling reaction proceeds in good yields with secondary cyclic alcohols under mild conditions. The stereochemical outcome likely due to fast nucleophilic capture of a non-planar carbocations (hyperconjomers) stabilized by ring hyperconjugation.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004262
- Subject Headings
- Intermediates (Chemistry), Nuclear medicine, Organometallic chemistry, Physical organic chemistry, Reaction mechanisms (Chemistry), Tomography, Emission
- 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
- Synthesis, structural characterization and biological studies of organotin polyethers (Sn-O).
- Creator
- Barot, Girish Vallabhbhai., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Cancer is the second leading cause of death in the western world. In order to treat various types of cancer, platinum-based drugs are most widely employed as metal-containing chemotherapeutic agents. However, their clinical usage is hindered by toxic side effects, and by the emergence of drug resistance. Our focus was to replace platinum with less toxic metal like tin which can give better alternatives for cancer treatment. The major aim of our study was to synthesize novel organotin...
Show moreCancer is the second leading cause of death in the western world. In order to treat various types of cancer, platinum-based drugs are most widely employed as metal-containing chemotherapeutic agents. However, their clinical usage is hindered by toxic side effects, and by the emergence of drug resistance. Our focus was to replace platinum with less toxic metal like tin which can give better alternatives for cancer treatment. The major aim of our study was to synthesize novel organotin polyethers (Sn-O) which can be used to combat cancer. Preliminary results from our laboratory using organotin polyethers, that were synthesized by varying the structure of diols showed growth inhibition in Balb-3T3 cells. This study directly led us to hypothesize the two structural windows, first by changing the distance between diol and second, by presence of unsaturation in diols, the biological activity of organotin polyethers (Sn-O) can be enhanced significantly. Different series of polymeric compounds were synthesized based upon these two structural windows and the formation of products was validated using standard techniques like infrared spectroscopy (IR), light scattering photometer, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and nuclear magnetic resonance (NMR). The synthesized polymers arrested the growth of cancer cell lines including bone, prostate, colon, breast, pancreas and lung cancer derived cell lines in vitro. In number of instances where chemotherapeutic index values of two and greater were found that these polymers are significantly more active against cancer cells than non-cancerous cells in culture., These results support the starting premise that the polymers may exhibit cancer cell selectivity. In general, it was found that the presence of unsaturation increased the probability that the polyether would inhibit the growth of various cancer cell lines. Further, in some cases, polyethers with short distances between the oxygen atoms showed a superior ability to inhibit the growth of various cancer cell lines in comparison to those with longer distances between the oxygen atoms. These results provide a framework for the discovery of novel cancer therapeutics.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/186672
- Subject Headings
- Organometallic polymers, Cancer, Molecular aspects, Apoptosis, Molecular aspects, Antineoplastic agents, Testing, Polymers in medicine
- Format
- Document (PDF)
- Title
- Determination and evaluation of electrical properties of metal-containing condensation polymers.
- Creator
- Battin, Amitabh J., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
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Doped electrically conductive polymers are one of the critical materials that have allowed the current technological revolution. Essentially all of today's applications of doped conductive polymers involve vinyl-related polymers. While the application of conductive polymers is rapidly increasing, there is need for additional materials with different electrical behaviors. The current focus is on studying condensation polymers that contain a metal atom and the possibility of undergoing entire...
Show moreDoped electrically conductive polymers are one of the critical materials that have allowed the current technological revolution. Essentially all of today's applications of doped conductive polymers involve vinyl-related polymers. While the application of conductive polymers is rapidly increasing, there is need for additional materials with different electrical behaviors. The current focus is on studying condensation polymers that contain a metal atom and the possibility of undergoing entire chain delocalization of electrons. The different series of organometallic condensation polymers were synthesized by employing interfacial polycondensation technique and characterization of these products were carried out using standard techniques like light scattering photometer, fourier transform infrared spectroscopy (FTIR), matrix assisted laser desorption ionization time of flight mass spectroscopy (MALDI TOF MS) and nuclear magnetic resonance spectroscopy (NMR). The electrical measurements were carried out employing Genrad 1650-B impedance spectroscopy. Prior studies conducted in this area have led to the pathway of looking at two aspects; first, surveying 60 metal-containing polymers that can undergo entire chain delocalization studying the effect of different substituents on their electrical properties and secondly, doping selected candidates employing iodine. The products derived from 2-nitro-1,4-phenylenediamine and N-methyl-1,4- pheneylenediamines with titanocene dichloride exhibited about 10 3 to 10 5 fold magnitude increases in the electrical conductivity on doping with iodine, moving it near conductive region. This increase is dependent on the concentration of the iodine and is cyclic. The results support the starting premise that selected metal-containing condensation polymers can be doped to increase their electrical conductivity., Further investigation is warranted to see if metal-containing condensation polymers can be important materials in the electronic industry. This research sets the stage for studying not only metal-containing polymeric materials but also to investigate the ability to increase the conductivity of other condensation polymers such as nylons and polyesters through doping.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/216415
- Subject Headings
- Polycondensation, Condensation products (Chemistry), Polymers and polymerization, Polymers, Electric properties
- Format
- Document (PDF)
- Title
- TUMOR-ASSOCIATED MUC1-TN GLYCOPEPTIDE INTERACTIONS WITH MACROPHAGE GALACTOSE LECTIN.
- Creator
- Beckwith, Donella Marie, Cudic, Mare, Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
- Abstract/Description
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The transformation from normal to malignant phenotype in human cancers is associated with aberrant cell-surface glycosylation. Mucin 1 (MUC1), the heavily glycosylated cell-surface mucin, is altered in both, expression and glycosylation pattern in many cancers. The presence of truncated glycan structures, often capped by sialic acid, commonly known as tumor-associated carbohydrate antigens (TACAs), play key roles in tumor initiations, progression, and metastasis. Accumulating evidence...
Show moreThe transformation from normal to malignant phenotype in human cancers is associated with aberrant cell-surface glycosylation. Mucin 1 (MUC1), the heavily glycosylated cell-surface mucin, is altered in both, expression and glycosylation pattern in many cancers. The presence of truncated glycan structures, often capped by sialic acid, commonly known as tumor-associated carbohydrate antigens (TACAs), play key roles in tumor initiations, progression, and metastasis. Accumulating evidence suggests that expression of TACAs is associated with escape of immune defenses. Human macrophage galactose-type lectin (hMGL, HML, CD301 or CLEC10A), a C-type lectin expressed by antigen presenting cells (APC), is a receptor of mucin-type TACAs, -GalNAc (Thomsen nouvelle antigen; Tn; CD175) and its 2,6-sialylated derivative (sTn; CD175s). To date, the relative contributions of these glycans, as well as underlying peptide backbone, and different degrees of valency, on binding thermodynamics and kinetics with hMGL remains elusive. In order to discern the subtle utility of these distinct features, chemical syntheses of the MUC1, HGVTSAPDTRPAPGSTAPPA tandem repeat sequence, and its site-specific serine (Ser) and threonine (Thr) glycosylated analogs were carried out. Circular dichroism (CD) spectroscopy experiments detected increasing structural order of the Thr glycopeptides compared to its nonglycosylated analogs. Isothermal titration calorimetry (ITC) data analysis of lectin binding to the Thr glycopeptides invariably showed enthalpy-driven processes. Affinity enhancement of the Thr glycopeptides for hMGL occurred relative to free GalNAc, revealing an increasing trend in affinity by one order of magnitude, for mono- (KD = 6-8 μM) to triglycosylated (KD = 600 nM) MUC1 peptides. To delineate the relevance of the solvent structure in the protein carbohydrate recognition process, experiments in D2O were performed, exposing enthalpy-entropy compensation differences. KinITC analysis highlighted prolonged complex lifetimes. Furthermore, atomic force microscopy (AFM) based dynamic single-molecule force spectroscopy (SMFS) provided molecular level insight into the energy landscapes governing recognition of the MUC1(Tn)-hMGL complexes. In summary, our results suggest that contact with hMGL critically depends on the type of TACA, nature of the vicinity surrounding the glycan, and its density. This highlights the importance and current efforts in design of prophylactic and therapeutic cancer vaccines with special emphasis on the synthetic glycopeptide vaccines.
Show less - Date Issued
- 2021
- PURL
- http://purl.flvc.org/fau/fd/FA00013750
- Subject Headings
- Antigens, Tumor-Associated, Carbohydrate, Mucin-1, Cancer vaccines, Glycopeptides
- 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
- CREATINE PHOSPHOKINASE ISOENZYME ANALYSIS BY SELECTIVE ACTIVATION WITH THIOLS AND INHIBITION BY ANTIBODIES. AN EVALUATION AND ADAPTATION TO AUTOMATED ANALYSIS.
- Creator
- BERNARD, DONALD JAMES., Florida Atlantic University, Schultz, Franklin A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Analysis of creatine phosphokinase (CPK) isoenzymes is the best clinical test for diagnosis of heart disease. Two new methods for quantitative analysis of these enzymes are selective activation with thiols and specific inhibition by antibodies. These new methods and the conventionally used technique of electrophoresis are comparatively evaluated using assayed controls and cardiac patient serum samples. Results indicate that thiol activation and antibody inhibition are preferred methods for...
Show moreAnalysis of creatine phosphokinase (CPK) isoenzymes is the best clinical test for diagnosis of heart disease. Two new methods for quantitative analysis of these enzymes are selective activation with thiols and specific inhibition by antibodies. These new methods and the conventionally used technique of electrophoresis are comparatively evaluated using assayed controls and cardiac patient serum samples. Results indicate that thiol activation and antibody inhibition are preferred methods for CPK cardiac isoenzyme analysis because they have lower levels of detection, fewer false negative results, and are considerably more efficient than electrophoresis. The new techniques also are adapted to automated spectrophotometric instrumentation, which further contributes to their accuracy and procedural efficiency. Thus, thiol activation and antibody inhibition methods should provide more sensitive and reliable CPK isoenzyme analysis for critical supportive evidence in heart disease diagnosis and treatment
Show less - Date Issued
- 1979
- PURL
- http://purl.flvc.org/fcla/dt/13982
- Subject Headings
- Chemistry, Analytic
- Format
- Document (PDF)
- Title
- Cyclic lipodepsipeptides as lead structures for the discovery of new antiobiotics.
- Creator
- Bionda, Nina., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
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With antimicrobial resistance to current drugs steadily rising, the development of new antibiotics with novel mechanisms of action has become an imperative. The majority of life-threatening infections worldwide are caused by "ESKAPE" pathogens which are encountered in more than 40% of hospital-acquired infections, and are resistant to the majority of commonly used antibiotics. Naturally occurring cyclic depsipeptides, microbial secondary metabolites that contain one or more ester bonds in...
Show moreWith antimicrobial resistance to current drugs steadily rising, the development of new antibiotics with novel mechanisms of action has become an imperative. The majority of life-threatening infections worldwide are caused by "ESKAPE" pathogens which are encountered in more than 40% of hospital-acquired infections, and are resistant to the majority of commonly used antibiotics. Naturally occurring cyclic depsipeptides, microbial secondary metabolites that contain one or more ester bonds in addition to amide bonds, have emerged as an important source of pharmacologically active compounds or lead structures for the development of novel antibiotics. Some of those peptides are either already marketed (daptomycin) or in advanced stages of clinical development (ramoplanin). Structurally simple, yet potent, fusaricidin/LI-F and lysobactin families of naturally occurring antibiotics represent particularly attractive candidates for the development of new antibacterial agents capable of overco ming infections caused by multidrug-resistant bacteria. These natural products exhibit potent antimicrobial activity against a variety of clinically relevant fungi and Gram-positive bacteria. Therefore, access to these classes of natural products and their synthetic analogs, combined with elucidation of their mode of action represent important initial steps toward full exploitation of their antmicrobial potential. This dissertation describes a general approach toward the solid-phase synthesis of fusaricidin/LI-F and lysobactin analogs and an extensive structure-activity relationship (SAR) study. We have devised a simple and robust preparation strategy based on standard Fmoc solid-phase peptide synthesis protocols., The SAR study revealed key structural requirements for fusaricidin/LI-F and related cyclic lipopeptides antibacterial activity, including the presence of the guanidino moietly at the end of the lipidic tail, hydrophobic amino acid residues, and peptide conformation Moreover, substitution of the ester bond with an amide bond significantly improved stability under physiologically relevant conditions and reduced toxicity. In addition, we have shown that these antibacterial peptides exert their mode of action via a novel mechanism, which invloves bacterial membrane interactions, followed by peptide internalization. Altogether, the research described in this dissertation demonstrates that new antibiotics derived from fusaricidin/LI-F natural products, have the potential to meet the challenge of antibiotic resistance in Gram-positive bacteria.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/FAU/3360768
- Subject Headings
- Microbial peptides, Drugs, Design, Peptides, Therapeutic use, Genetic engineering, Antibacterial agents, Peptide antibiotics, Research, Methodology, Peptide antibiotics, Analysis
- 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
- Comparison of chemotaxonomic methods for the determination of periphyton community composition.
- Creator
- Browne, Jamie L., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Pigment-based chemotaxonomy uses relative amounts of photosynthetic pigments (biomarkers) within algae samples to determine the algal class composition of each sample. Chemotaxonomy has been applied successfully to phytoplankton communities, but its efficacy for periphyton has not yet been established. This study examined the ability of simultaneous linear equations (SLE), CHEMTAX, and the Bayesian Compositional Estimator (BCE) to determine algal class composition in Florida Everglades...
Show morePigment-based chemotaxonomy uses relative amounts of photosynthetic pigments (biomarkers) within algae samples to determine the algal class composition of each sample. Chemotaxonomy has been applied successfully to phytoplankton communities, but its efficacy for periphyton has not yet been established. This study examined the ability of simultaneous linear equations (SLE), CHEMTAX, and the Bayesian Compositional Estimator (BCE) to determine algal class composition in Florida Everglades periphyton. The methods were applied to artificial datasets, mixed lab cultures of known composition, and Everglades periphyton samples for which microscopic biovolume data was available. All methods were able to return accurate sample compositions for artificial data and mixed lab cultures. Correlation between pigment methods and microscopic results for natural periphyton samples was poor. SLE and CHEMTAX returned similar results for all samples while BCE performed less well.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2100582
- Subject Headings
- Water quality biological assessment, Periphyton, Water, Phosphorus content, Freshwater algae
- Format
- Document (PDF)
- Title
- Synthesis and structural characterization of intermediates towards the preparation of a polyphosphonate ester containing L-dopa for the potential treatment of Parkinson's disease.
- Creator
- Chamely-Wiik, Donna M., Florida Atlantic University, Haky, Jerome E., Carraher, Charles E., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
We have synthesized intermediates towards the preparation of a polyphosphonate ester containing L-dopa for the potential treatment of Parkinson's disease. A synthetic strategy was devised to be more reproducible than the original strategy. We discovered some very interesting chemistry of one of the intermediates produced from this new scheme. We synthesized L-N-(butyloxycarbonyl)-3-(3-hydroxy-ethyl-4-(benzyloxy)-phenyl)alanine benzylester, a compound containing a secondary alcohol moiety that...
Show moreWe have synthesized intermediates towards the preparation of a polyphosphonate ester containing L-dopa for the potential treatment of Parkinson's disease. A synthetic strategy was devised to be more reproducible than the original strategy. We discovered some very interesting chemistry of one of the intermediates produced from this new scheme. We synthesized L-N-(butyloxycarbonyl)-3-(3-hydroxy-ethyl-4-(benzyloxy)-phenyl)alanine benzylester, a compound containing a secondary alcohol moiety that had a unique set of characteristics. Upon reduction of the N-(tert-butyloxycarbonyl)-3-(3-acetyl-4-benzyloxyphenyl)-L-alanine benzylester, which contained a ketone moiety, to produce the secondary alcohol, we discovered that the materials that were formed included a pair of diastereomers of the secondary alcohol, each diastereomer also exhibiting two individually stable conformational isomers. We believe that the conformational isomers were generated by rotation of the C-N bond of the BOC carbamate, and were so stable that they could be separated by HPLC and NMR techniques. Energy optimization studies and molecular modeling techniques were performed using HyperChem, and rotational barrier energy values were calculated for the different conformational isomers for each of the diastereomers. HPLC and NMR techniques were also used to obtain information about these materials. Using the calculated data from these studies, and analyzing the HPLC chromatograms and NMR spectra we were able to fully determine the assignments for the diastereomers and the individual conformational isomers. We discovered that the SS form was synthesized preferentially over the SR form and that in both cases the E conformation was energetically more stable than the Z form. Octanol/water partition coefficient values (Log P0ct) were also determined and compared to L-dopa and dopamine. We concluded that the values for the dimeric compound that we synthesized and many of its potential products of degradation were significantly higher than that for both L-dopa and dopamine. This may be an indication that this material has a higher degree of lipophilicity than L-dopa itself, having more potential to cross the blood brain barrier. We believe that these intermediate materials serve as good indication of how a polyphosphonate ester containing L-dopa would compare as a potential drug for Parkinson's disease.
Show less - Date Issued
- 2004
- PURL
- http://purl.flvc.org/fcla/dt/12108
- Subject Headings
- Parkinson's disease--Treatment, Antiparkinsonian agents, Dopa, Organophosphorus compounds--Synthesis, Chemistry, Analytic
- 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
- Synthesis and photophysical measurements of a series of lanthanide-benzenedicarboxylate coordination polymers.
- Creator
- Clark, Jessica Montressa., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Within solid-state chemistry, coordination polymers have gained interest for use in various applications such as sensing, catalysis, display technology, hydrogen storage, etc. The use of lanthanide ions in these materials provides a mean of exploring how structure may affect luminescence efficiency. In this study, the photophysics of several lanthanide benzenecarboxylates was studied. This data combined with data from other coordination polymers created in our lab indicate that the...
Show moreWithin solid-state chemistry, coordination polymers have gained interest for use in various applications such as sensing, catalysis, display technology, hydrogen storage, etc. The use of lanthanide ions in these materials provides a mean of exploring how structure may affect luminescence efficiency. In this study, the photophysics of several lanthanide benzenecarboxylates was studied. This data combined with data from other coordination polymers created in our lab indicate that the established guidelines for producing highly efficient materials may not correlate directly from solution to the solid state and that structure may also play a role.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3362332
- Subject Headings
- Rare earth metals catalysts, Metallic composites, Speciation, Lanthanide shift reagents, Organic compounds, Synthesis, Polymers, Biotechnology
- Format
- Document (PDF)
- Title
- Study of Cell Penetrating Peptide Uptake and Cancer Cell Discrimination with Raman Spectroscopy and Microscopy.
- Creator
- Cosme, Patrick Jason, Terentis, Andrew C., Florida Atlantic University, Charles E Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Cell penetrating peptides (CPPs) are short sequences of amino acids that excel in crossing the cellular membrane without inducing cytotoxicity Interest in these peptides stem from their ability to be attached, and grant their penetrating properties to, a variety of cargo In this work we have combined the application of Confocal Raman Microscopy (CRM) and Atomic Force Microscopy for the first time to examine the interactions of unlabeled Transportan (TP), one of the most well studied CPPs,...
Show moreCell penetrating peptides (CPPs) are short sequences of amino acids that excel in crossing the cellular membrane without inducing cytotoxicity Interest in these peptides stem from their ability to be attached, and grant their penetrating properties to, a variety of cargo In this work we have combined the application of Confocal Raman Microscopy (CRM) and Atomic Force Microscopy for the first time to examine the interactions of unlabeled Transportan (TP), one of the most well studied CPPs, with mammalian cells CRM’s capability to discriminate control and treated cell groups was verified by principal component analysis (PCA) and linear discriminant analysis (LDA) and was 93-100% accurate We’ve determined that at a concentration of 20 μM TP enters cells through a non-endocytotic mechanism, has a high affinity for the cytoplasm and membranes, and results in a significant increase in cellular stiffness Our work provides the first direct evidence of this cell-stiffening phenomenon SFTI-1, the smallest member of a bicyclic, cysteine rich class of CPPs, was examined by CRM to determine the potential role of cyclic structure on cellular uptake The peptide, along with monocyclic and linear analogs was heavy isotope labeled and incubated with mammalian cells at numerous concentrations and timespans Our work is the first SFTI-1 uptake study forgoing the use of fluorophore conjugates, which have been linked to artificial cellular uptake We demonstrate herein the absence of any CRM detectable uptake, providing the first evidence that SFTI-1 may not be a CPP Finally, CRM was applied to the discrimination of normal and basal cell carcinoma cells obtained from the same donor The use of patient matched cells avoids the normal biochemical variations that exist among individuals, ensuring that discrimination is based solely on the cell’s diseased state CRM spectra, analyzed by PCA and LDA, were capable of spectral discrimination with 100% accuracy Major differences in the cancerous cells were an increase in lipids and nucleic acids, and an overall decrease in protein We also demonstrate an enhancement in Raman signal through the use of an aluminum foil substrate, providing a practical approach for measuring cells with thin morphologies
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004756
- Subject Headings
- Peptides--Analysis, Peptides--Therapeutic use, Peptides--Physiological transport, Cellular signal transduction, Raman spectroscopy, Infrared spectroscopy
- Format
- Document (PDF)
- Title
- Neuroprotection from induced glutamate excitotoxicity by Conus brunneus conopeptides in a stroke-related model.
- Creator
- Crouch, Rebecca A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
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Cone snails are carnivorous marine mollusks, utilizing their neuropeptide-rich venom for prey capture. The venom of Conus brunneus, a wide-spread Eastern Pacific vermivore, has not been extensively studied. In the current work, peptides from the dissected venom were characterized and tested using preliminary bioassays. Six peptides (A-F) were isolated and tested. Three peptide identities were determined by comparison with previously reported data: bru9a (A), bru3a (F), and an a-conotoxin (E)....
Show moreCone snails are carnivorous marine mollusks, utilizing their neuropeptide-rich venom for prey capture. The venom of Conus brunneus, a wide-spread Eastern Pacific vermivore, has not been extensively studied. In the current work, peptides from the dissected venom were characterized and tested using preliminary bioassays. Six peptides (A-F) were isolated and tested. Three peptide identities were determined by comparison with previously reported data: bru9a (A), bru3a (F), and an a-conotoxin (E). Preliminary screening in a stroke-related model of induced glutamate excitotoxicity in primary neuronal cells and PC12 cell cultures indicated potential neuroprotective activity of peptide fractions A, D, and F. Further testing is necessary to determine and verify structure, activity, target, and mechanism of action of the promising peptides from C. brunneus, which may prove effective neuropharmacological agents to treat stroke.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3362331
- Subject Headings
- Gastropoda, Venom, Therapeutic use, Peptides, Structure, Neuroprotective agents, Central nervous system, Diseases, Treatment
- Format
- Document (PDF)
- Title
- Design, Synthesis and Applications of Lanthanide Metal-Organic Frameworks based on 1,2,4,5-benzenetetracarboxylic acid.
- Creator
- Dixon, Joseph William, De Lill, Daniel T., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
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The organic linker 1,2,4,5-benzenetetracarboxylic acid (BTC) has been widely used in the construction of lanthanide metal-organic frameworks (MOFs) due the high symmetry and versatile nature of its structure. Under identical hydrothermal reaction conditions, it was discovered that lanthanide BTC MOFs will form one of four unique structures based on its location in the series (La-Sm, Eu-Tb, Dy-Tm, Yb-Lu). This is uncommon in LOF materials, as in many cases the same compound can be produced for...
Show moreThe organic linker 1,2,4,5-benzenetetracarboxylic acid (BTC) has been widely used in the construction of lanthanide metal-organic frameworks (MOFs) due the high symmetry and versatile nature of its structure. Under identical hydrothermal reaction conditions, it was discovered that lanthanide BTC MOFs will form one of four unique structures based on its location in the series (La-Sm, Eu-Tb, Dy-Tm, Yb-Lu). This is uncommon in LOF materials, as in many cases the same compound can be produced for all of the lanthanides or two different structures may be observed for the first and second half of the series. Descriptions and comparisons of these structures as discussed herein, noticeably the decrease in coordination number and the lanthanide-oxygen bond lengths as the lanthanide atomic number increases. This thesis also attempts to use these compounds to catalyze a model mixed-aldol reaction. Two closely related BTC compounds from yttrium and uranium are also presented. The structure of the yttrium BTC MOFs was identical to that of the Eu, Gd and Tb compounds.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004494, http://purl.flvc.org/fau/fd/FA00004494
- Subject Headings
- Coordination compounds, Inorganic compounds -- Synthesis, Organorare earth metal compounds, Rare earth metals
- 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
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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
- PHOSPHORUS SEQUESTRATION AND BIOREMEDIATION: PHOSPHORUS-31 NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY.
- Creator
- Duersch, Bobby G., Louda, J. William, Florida Atlantic University, Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science
- Abstract/Description
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Eutrophication is an increase in primary plant nutrients (Nitrogen [N] and Phosphorus [P]) in oceans, estuaries and lakes. The consequences of eutrophication are harmful algal blooms (HABs), resulting in algal toxin production and the depletion of oxygen as the extensive biomass decays. P is often the limiting nutrient and is viewed as a significant environmental problem. Most of the excess P that enters aquatic ecosystems originates from anthropogenic sources such as fertilizers, sewage,...
Show moreEutrophication is an increase in primary plant nutrients (Nitrogen [N] and Phosphorus [P]) in oceans, estuaries and lakes. The consequences of eutrophication are harmful algal blooms (HABs), resulting in algal toxin production and the depletion of oxygen as the extensive biomass decays. P is often the limiting nutrient and is viewed as a significant environmental problem. Most of the excess P that enters aquatic ecosystems originates from anthropogenic sources such as fertilizers, sewage, animal wastes, compost, crop residues, and wastewater. Over time, one of the main reservoirs of P becomes organic P (Po). We investigated the chemical nature and dynamics of P in cyanobacteria, horse manure, stormwater treatment areas, and rice fields. To better understand the chemical nature of P, the identification of specific P compounds was required, which was achieved through 31P nuclear magnetic resonance (NMR) spectroscopy. We investigated how paramagnetic metals and quadrupolar nuclei cause severe line broadening, peak shifts, and decreased the signal to noise ratio. Results revealed that certain Po forms are readily bioavailable to Microcystis aeruginosa. Additionally, the potential heterotrophic use of the organic portion (e.g., glucose, glycerol) of these P compounds are indicated for the growth and persistence of Microcystis aeruginosa. We showed that the cultivation of rice (Oryza sativa L.) had been found to effectively reduce P from agrarian soil and water through plant uptake and, therefore, minimizing downstream eutrophication. Soil, water, sugarcane, and rice plants at two different stages were analyzed for twelve different elements. Finally, we examined how a “relic” agrarian ditch in Stormwater Treatment Area 1 East (STA-1E) can be used for the retention and sequestration of P and other nutrients. The STAs were established to capture P from agricultural and other sources before reaching the Everglades. Retained P is primarily stored in the wetland soils and sediments, generated through a collection of interrelated physical, chemical, and biological processes.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013594
- Subject Headings
- Nuclear magnetic resonance spectroscopy, Eutrophication, Phosphorus--Environmental aspects, Bioremediation
- Format
- Document (PDF)
- Title
- A New Approach to Sensitized Luminescence in Trivalent Lanthanide Coordination Polymers: From Fundamental Luminescence and Crystal Engineering Toward Sensing Applications.
- Creator
- Einkauf, Jeffrey D., De Lill, Daniel T., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
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Luminescent lanthanide containing coordination polymers and metal-organic frameworks hold great potential in many applications due to their distinctive spectroscopic properties. While the ability to design coordination polymers for specific functions is often mentioned as a major benefit bestowed upon these compounds, the lack of a meaningful understanding of the crystal engineering and luminescence in lanthanide coordination polymers remains a significant challenge toward functional design....
Show moreLuminescent lanthanide containing coordination polymers and metal-organic frameworks hold great potential in many applications due to their distinctive spectroscopic properties. While the ability to design coordination polymers for specific functions is often mentioned as a major benefit bestowed upon these compounds, the lack of a meaningful understanding of the crystal engineering and luminescence in lanthanide coordination polymers remains a significant challenge toward functional design. Currently, the study of luminescence attributed to these compounds is based on the antenna effect as derived from molecular systems, where organic antennae are used to facilitate lanthanide-centered luminescence. This molecular based approach does not take into account the unique features of extended network solids, particularly the formation of band structure. By comparing molecular and band-based approaches, it was determined that the band structure of the organic sensitizing linker needs to be considered when evaluating the luminescence of lanthanide coordination polymers. This new model, as well as work on the crystal engineering and sensor applications of these materials will be presented.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004890, http://purl.flvc.org/fau/fd/FA00004890
- Subject Headings
- Rare earth metals., Lanthanide shift reagents., Organic compounds--Synthesis., Inorganic compounds--Synthesis., Metallic composites--Speciation., Polymeric composites., Organorare earth metal compounds., Nanostructured materials.
- Format
- Document (PDF)
- Title
- Aggregation Inhibition and Detection of Alzheimer’s Amyloidogenic and Oligomeric Peptides.
- Creator
- Elbassal, Esmail A. E., Du, Deguo, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
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Protein aggregation, oligomer and fibril formation is one of the dominant characteristics in the pathogenesis of a number of neurodegenerative diseases, such as Alzheimer’s disease (AD). Inhibition of toxic oligomer and fibril formation is one of the approaches to find potential drug candidates for AD. Additionally, early diagnosis of these amyloid species can provide mechanistic understanding of protein aggregation and thus can pave the way for preventing the onset of AD. The aim of this...
Show moreProtein aggregation, oligomer and fibril formation is one of the dominant characteristics in the pathogenesis of a number of neurodegenerative diseases, such as Alzheimer’s disease (AD). Inhibition of toxic oligomer and fibril formation is one of the approaches to find potential drug candidates for AD. Additionally, early diagnosis of these amyloid species can provide mechanistic understanding of protein aggregation and thus can pave the way for preventing the onset of AD. The aim of this dissertation was 1) to explore the effects of charged cholesterol derivatives on the aggregation kinetic behavior of Amyloid-β40 (Aβ40), 2) to probe Aβ40 oligomer and amyloid formation in vitro using gold nanoparticles (AuNPs), and 3) to monitor the kinetic effect of various natural product molecules on Aβ40 aggregation in vitro. In the first chapter, a general introduction about AD as an amyloidogenic disease, amyloid cascade hypothesis, and the manipulation of Aβ peptides aggregation kinetics using different approaches was presented. In the second chapter, we studied the effects of oppositely charged cholesterol derivatives on the aggregation kinetics of Aβ. In the third chapter, we developed a gold nanoparticles (AuNPs) assay to probe Aβ40 oligomers and amyloid formation. In chapter IV, we monitored the effects of various small molecules on the aggregation kinetics of Aβ40. In chapter V, we discussed the methods and experimental details.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013009
- Subject Headings
- Alzheimer's disease, Amyloid beta-protein, Oligomers, Protein Aggregates, Neurodegenerative Diseases
- Format
- Document (PDF)