This thesis details my investigations of marine cyanobacterial natural products that resulted in the discovery of thirteen new secondary metabolites, the isolation of over fifteen previously reported metabolites and the biosynthetic investigation of two additional cyanobacterial compounds. Two novel lipopeptides were identified from a Lyngbya majuscula and Schizothrix sp. assemblage...
This dissertation describes studies of isoprenoid biosynthesis in the
phytoflagellate Euglena gracilis. Elucidation of a novel isoprerioid pathway, the 2-Cmethyl-D-erythritol-4-phosphate (MEP) pathway, in addition to the generally known
mevalonate (MVA) pathway, led to extensive exploration of the distribution of both pathways in a variety of organisms. To date, photosynthetic eukaryotes...
Marine organisms produce a variety of secondary metabolites for defense, communication, and reproduction. While these uses are essential for the organisms' survival, marine natural products have demonstrated their value to human society as well. Asian countries used algae for centuries to treat or prevent illnesses as wide-ranging as cough, gout,...
Cyanobacteria are rich in biologically active secondary metabolites, many of which have potential application as anticancer or antimicrobial drugs or as useful probes in cell biology studies. A Jamaican isolate of the marine cyanobacterium, Lyngbya majuscula was the source of a novel antifungal and cytotoxic secondary metabolite, hectochlorin. The structure...
Among the myriad of naturally occurring bioactive compounds are the aminocyclopentitol-containing natural products that represent a family of sugar-derived microbial secondary metabolites, such as the antibiotics pactamycin, allosamidin, and trehazolin. Pactamycin, a structurally unique aminocyclitol antibiotic isolated from Streptomyces pactum, consists of a 5-membered ring aminocyclitol (cyclopentitol) unit, two aromatic...
Wood-plastic composites (WPCs) are one of the fastest-growing sectors of the
wood composites industry. However, the strengths of WPCs are typically low
because of the poor interfacial adhesion between hydrophilic wood and
hydrophobic thermoplastics. A compatibilizer that can form bridges between wood
and plastics is required to give WPCs desirable...
Tuberculoѕiѕ (TB) iѕ a number one killer among treatable infectious diseases. It is caused by the pathogenic bacterium Mycobacterium tuberculoѕiѕ that primarily affects the lungѕ. It infects one third of the world population and kills approximately 2 million people each year (based on WHO report). Drug-reѕiѕtant TB haѕ become a...
This thesis describes the chemical investigation of marine cyanobacteria collected in Madagascar and Panama with an emphasis on the isolation and structure elucidation of medicinally relevant secondary metabolites.
A collection of the marine cyanobacterium Lyngbya majuscula from the Radames Islands, Madagascar yielded two new cyclic depsipeptides, radamamides A and B,...
7,7'-Dihydroxy-8,8'-biquinolyl (azaBINOL) was prepared from 7-hydroxyquinoline via N,N-dimethyl O-quinol-7-yl carbamate by directed ortho-metallation followed by FeCl₃-mediated oxidative coupling of the 8-lithioquinoline intermediate. Saponification of the resulting dicarbamate provided crystalline (±)-azaBINOL in 56% overall yield. 6,6'-Bis(dimethylaminocarbonyl)-7,7'-dihydroxy-8,8´-biquinolyl was prepared from the same dicarbamate by a double anionic-Fries rearrangement in 43% yield. 7,7'-Bis(diethylamino-carbonyloxy)-6,6'-diiodo-8,8´-biquinolyl...