A5072289043- Marine Sponges and Natural Products
- Microbial Natural Products and Biosynthesis
- Chemical synthesis and alkaloids
- Genomics and Phylogenetic Studies
- Metabolomics and Mass Spectrometry Studies
- Synthesis and Biological Activity
- Cholinesterase and Neurodegenerative Diseases
- Genetics, Bioinformatics, and Biomedical Research
- Synthesis and Catalytic Reactions
- Molecular spectroscopy and chirality
- Drug Transport and Resistance Mechanisms
- Traditional and Medicinal Uses of Annonaceae
- Pharmacogenetics and Drug Metabolism
- Spectroscopy and Quantum Chemical Studies
- Alkaloids: synthesis and pharmacology
- Microbial Community Ecology and Physiology
- Synthetic Organic Chemistry Methods
- Chemical Synthesis and Analysis
- Enzyme function and inhibition
- Plant biochemistry and biosynthesis
University of California, San Diego
2013-2025
University of Montana
2017-2018
Abstract Culture-based microbial natural product discovery strategies fail to realize the extraordinary biosynthetic potential detected across earth’s microbiomes. Here we introduce Small Molecule In situ Resin Capture (SMIRC), a culture-independent method obtain products directly from environments in which they are produced. We use SMIRC capture numerous compounds including two new carbon skeletons that were characterized using NMR and contain structural features are, best of our knowledge,...
The configurational analysis of amino acids (AAs) in natural product peptides, often containing nonproteinogenic AAs, is mostly carried out by the venerable Marfey's method using a chiral derivatizing agent (CDA) 1-fluoro-2,4-dinitrophenyl-5-l-alaninamide (l-FDAA)─Marfey's reagent─which undergoes SNAr reaction 1° group. resulting AA-DAA derivatives are well-separated reversed-phase HPLC, but some DAA resist resolution. Here, we report synthesis and characterization two CDAs: l-FDTA (4) which...
Two dimerized cyclic hexapeptides, antatollamides A (1) and B (2), were isolated from the colonial ascidian Didemnum molle collected in Pohnpei. The amino acid compositions sequences determined by interpretation of MS 1D 2D NMR data. Raney Ni reduction antatollamide cleaved dimer to corresponding monomeric hexapeptide with replacement Cys Ala. configuration 1 was established, after total hydrolysis, derivatization a new chiral reagent, (5-fluoro-2,4-dinitrophenyl)-Nα-l-tryptophanamide...
Three new bromotyrosine spiroisoxazoline alkaloids, lacunosins A and B (1 2) desaminopurealin (3), were isolated from a MeOH extract of the marine sponge Aplysina lacunosa that showed modest α-chymotrypsin inhibitory activity. The structures 1–3 share spirocyclohexadienyl-isoxazoline ring system found in purealidin-R several other Verongid secondary metabolites. Compounds 1 2 are coupled to glycine an isoserine methyl ester, respectively. Alkaloid 3 is linked, contiguously, O-1-aminopropyl...
Six new cyclopenta[g]indoles were isolated from a West Australian sponge, Trikentrion flabelliforme Hentschel, 1912, and their structures elucidated by integrated spectroscopic analysis. The compounds are analogues of previously described trikentrins, herbindoles, trikentramides related Axinellid sponges. assignment absolute configuration the was carried out largely comparative analysis specific rotation, calculated measured ECD, exploiting van't Hoff's principle optical superposition. Five...
The 2S configuration of the marine natural product distaminolyne A was recently disputed based upon total synthesis, yet paradoxically supported by a second independent synthesis from different research group. We now verify extensive chiroptical studies and support veracity EC ECD method originally used to prove it. origin apparent paradox appears lie in limits precision polarimetry context weakly rotatory molecules, which strikes cautionary note on reliability "reassignment" configurations...
Nine bromotyrosine alkaloids (BTAs), including debromoianthelline (1), pseudoceratinic acid (2a), methyl pseudoceratinate (2b), 13-oxo-ianthelline (3), aiolochroiamides A–D (4a,b and 5a,b), 7-hydroxypurealidin J (6), were isolated from a Bahamian Aiolochroia crassa (Hyatt; previously, Pseudoceratina crassa). The structures of 1–6 established 1H, 13C, 2D NMR spectra, IR, mass spectrometry data. Compounds 2–4 comprise an O-methyl-2,6-dibromotyrosyl ketoxime (subunit A) amide linked to variable...
Abstract Microbial natural products remain an important resource for drug discovery. Yet, commonly employed discovery techniques are plagued by the rediscovery of known compounds, relatively few microbes that can be cultured, and laboratory growth conditions do not elicit biosynthetic gene expression among myriad other challenges. Here we introduce a culture independent approach to product call Small Molecule In situ Resin Capture (SMIRC) technique. SMIRC exploits in environmental compound...
Examination of the MeOH extract sponge, Pseudoceratina cf. verrucosa, Berquist 1995 collected near Ningaloo Reef, Western Australia for selective acetylcholinesterase (AChE) inhibitors, yielded five new bromotyrosine alkaloids, methyl purpuroceratates A and B (1b 2b), purpuroceratic acid C (3a), ningalamides (4 5). The structures 1-4 share dibromo-spirocyclohexadienyl-isoxazoline (SIO) ring system found in purealidin-R, while ketoxime 5 is analogous to ianthelline purpurealidin I. planar all...