Ascorbic acid, or vitamin C, is well known as a co-factor for proline-hydroxylase and as an anti-oxidant. However, it is also capable of forming covalent bonds, particularly in the role of a nucleophile, henceforth termed 'ascorbylation'.
The ascorbylation of electrophiles can occur under physiological conditions. Furthermore, there are a number...
This dissertation details the investigation of an alternate pathway to
isoprenoids that occurs in plants and microorganisms, the non-mevalonate
pathway. This exploration of the pathway focuses on the second step, the
conversion of 1-deoxy-D-xylulose-5-phosphate (DXP) to 2-C-methylerythritol-4-phosphate (MEP) by the enzyme DXP isomeroreductase (DXR). These studies led to an appreciation...
In an effort to isolate and characterize cardiac glycosides C-17
binding site(s), we have synthesized different affinity and photoaffinity
C-17 side chain probes. These probes were screened for their
ability to inhibit Na⁺,K⁺-ATPase enzyme, a pharmacological receptor
of cardiac glycosides. The enzyme was isolated from hog kidney.
Screening of these...
This thesis is an account of my explorations into the field of natural products chemistry. These investigations led to the discovery of several novel secondary metabolites isolated from the marine cyanobacterium Lyngbya majuscula. In addition, biosynthetic investigations were undertaken using stable isotope-labeled precursors. The dominant role that NMR spectroscopy plays...
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...
Following surveys of seaweeds in Oregon and the Caribbean, four algal species were selected for study on the basis of their crude extract biological activity or thin-layer chromatographic characteristics. Extracts were fractionated by normal phase chromatography, including high performance liquid chromatography (HPLC). Derivatives (methyl esters, acetates, and benzoates) of natural...
This thesis is an investigation of the natural products deriving from marine algae and cyanobacteria and has resulted in the discovery of eleven new secondary metabolites. The structure elucidations of these new molecules were performed using a variety of spectroscopic techniques. Four new macrolides were isolated and characterized from the...
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...