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Isolation and Relative Configuration Determination of Two Pairs of Bioactive diastereomers from Cacospongia cf. linteiformis
Title
Isolation and Relative Configuration Determination of Two Pairs of Bioactive diastereomers from Cacospongia cf. linteiformis.
Creator
Zhang, Long, West, Lyndon, Graduate College
Abstract/Description
Cacospongia cf. linteiformis is a marine sponge collected from Bahamas possessing various bioactive compounds. Two pairs of diastereomers spongianolides E&F were isolated for the first time through function group modification acetylation, and their relative configurations were determined based on Nuclear Overhauser Effect Spectroscopy NOESY. The mixture of isomers of spongianolides E&F are exhibiting inhibition against Schnurri-3. Bioassays will be repeated to unveil the assignment of the...
Show moreCacospongia cf. linteiformis is a marine sponge collected from Bahamas possessing various bioactive compounds. Two pairs of diastereomers spongianolides E&F were isolated for the first time through function group modification acetylation, and their relative configurations were determined based on Nuclear Overhauser Effect Spectroscopy NOESY. The mixture of isomers of spongianolides E&F are exhibiting inhibition against Schnurri-3. Bioassays will be repeated to unveil the assignment of the bioactivities for the four isomers.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00005865
Format
Document (PDF)
Isolation and Structural Elucidation of Novel Bioactive Natural Products from Marine Organisms of the Western Atlantic Ocean
Title
Isolation and Structural Elucidation of Novel Bioactive Natural Products from Marine Organisms of the Western Atlantic Ocean.
Creator
Zhang, Long, West, Lyndon, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
The aim of this dissertation was to elaborate the exploration of biologically active secondary metabolites from the marine sponge Cacospongia cf. linteiformis collected from the Bahamas and the soft coral Briareum asbestinum collected from two different sites in Florida State, Boca Raton and Dry Tortugas. In chapter one, a review on previous chemical and biological studies of the marine sponge C. cf. linteiformis and soft coral B. asbestinum is provided. Particular attention is given to...
Show moreThe aim of this dissertation was to elaborate the exploration of biologically active secondary metabolites from the marine sponge Cacospongia cf. linteiformis collected from the Bahamas and the soft coral Briareum asbestinum collected from two different sites in Florida State, Boca Raton and Dry Tortugas. In chapter one, a review on previous chemical and biological studies of the marine sponge C. cf. linteiformis and soft coral B. asbestinum is provided. Particular attention is given to spongianolides and briarellins, two important classes of compounds isolated from C. cf. linteiformis and B. asbestinum, respectively, and their structural features and diverse bioactivities. In chapter two, the isolation and relative configuration determination of four epimeric sesterterpenoids, spongianolides E & F (18c, 18d, 19c, 19d) from C. cf. linteiformis collected from the Bahamas are discussed. Thanks to chemical modification (acetylation), diastereomeric 18c&18d and 19c&19d, respectively, were able to be isolated using chromatographic techniques for the first time, and then the relative configurations of 18c, 18d, 19c, 19d were determined based on NOESY NMR experiments. The bioactivity of mixture of compounds 18c, 18d, 19c, 19d were tested and it exhibited inhibition against Schnurri-3 (a regulator of postnatal bone mass). In chapter three, the isolation and structural elucidation of four new compounds, florellins A-D (49-52), from B. asbestinum collected off the coast of Boca Raton, FL are discussed. The molecular structures of these compounds were established by spectroscopic analysis. Compounds 49-52 are the first briarellins containing an acyl group at C-13, while 49 and 50 are the first briarellins possessing acylation at C-15. Florellins A–C (49-51) were screened and found cytotoxic against three human cell lines, BT474, WM266−4 and HEK293. In chapter four, the isolation and structural elucidation of four new compounds, florellins E-H (57-60), from B. asbestinum collected in Dry Tortugas, FL are discussed. The molecular structures of these compounds were established by spectroscopic analysis. Florellins F (58) and H (60) were screened against three human cell lines, BT474, WM266−4 and HEK293, but no cytotoxicity was exhibited. In chapter five, all the experimental procedures are described, including analytical instruments, animal materials, extraction and isolation processes, spectroscopic data and protocols of bioassays.
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Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FA00004850, http://purl.flvc.org/fau/fd/FA00004850
Subject Headings
Pharmacognosy., Natural products--Analysis., Marine pharmacology., Marine biotechnology., Marine algae--Biotechnology., Bioactive compounds.
Format
Document (PDF)
development and application of a numerical model for predicting the frequency response of the seabed from vertical profiles of sediment impedance
Title
The development and application of a numerical model for predicting the frequency response of the seabed from vertical profiles of sediment impedance.
Creator
Zhang, Jian Long., Florida Atlantic University, Schock, Steven G., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Interaction of normal incidence, wideband acoustic pulses with seabed is investigated to determine the acoustic frequency ranges that provide the most information about the sediment structure. An exact numerical model is developed for calculating the frequency response and impulse response of the seabed from an impedance profile of a sediment core. A database of impedance profiles from several ocean environments were studied to describe the shapes of commonly found impedance changes. The...
Show moreInteraction of normal incidence, wideband acoustic pulses with seabed is investigated to determine the acoustic frequency ranges that provide the most information about the sediment structure. An exact numerical model is developed for calculating the frequency response and impulse response of the seabed from an impedance profile of a sediment core. A database of impedance profiles from several ocean environments were studied to describe the shapes of commonly found impedance changes. The impulse response of the seabed is convolved with acoustic pulses to generate synthetic acoustic returns. The synthetic profiles are studied to determine the effect of operating frequency and bandwidth on resolution and on the accuracy of measuring impedance changes. This thesis explains why inversion procedures have failed to generate vertical impedance profiles of the seabed from normal incidence reflection data. The results of this work provide guidelines for selecting subbottom profiler array sizes and operating frequencies for quantitative sediment studies, and for subsampling cores.
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Date Issued
1996
PURL
http://purl.flvc.org/fcla/dt/15293
Subject Headings
Marine sediments--Acoustic properties, Seismic reflection method
Format
Document (PDF)
Guidelines for monitoring autophagy in Caenorhabditis elegans
Title
Guidelines for monitoring autophagy in Caenorhabditis elegans.
Creator
Hong Zhang, Jessica T Chang, Bin Guo, Malene Hansen, Kailiang Jia, Attila L Kovács, Caroline Kumsta, Louis R Lapierre, Renaud Legouis, Long Lin, Qun Lu, Alicia Meléndez, Eyleen J O'Rourke, Ken Sato, Miyuki Sato, Xiaochen Wang, Fan Wu
Abstract/Description
The cellular recycling process of autophagy has been extensively characterized with standard assays in yeast and mammalian cell lines. In multicellular organisms, numerous external and internal factors differentially affect autophagy activity in specific cell types throughout the stages of organismal ontogeny, adding complexity to the analysis of autophagy in these metazoans. Here we summarize currently available assays for monitoring the autophagic process in the nematode C. elegans. A...
Show moreThe cellular recycling process of autophagy has been extensively characterized with standard assays in yeast and mammalian cell lines. In multicellular organisms, numerous external and internal factors differentially affect autophagy activity in specific cell types throughout the stages of organismal ontogeny, adding complexity to the analysis of autophagy in these metazoans. Here we summarize currently available assays for monitoring the autophagic process in the nematode C. elegans. A combination of measuring levels of the lipidated Atg8 ortholog LGG-1, degradation of well characterized autophagic substrates such as germline P granule components and the SQSTM1/p62 ortholog SQST-1, expression of autophagic genes and electron microscopy analysis of autophagic structures are presently the most informative, yet steady-state, approaches available to assess autophagy levels in C. elegans. We also review how altered autophagy activity affects a variety of biological processes in C. elegans such as L1 survival under starvation conditions, dauer formation, aging, and cell death, as well as neuronal cell specification. Taken together, C. elegans is emerging as a powerful model organism to monitor autophagy while evaluating important physiological roles for autophagy in key developmental events as well as during adulthood.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FAUIR000529
Format
Document (PDF)