C3 and 2D C3 Marfey's Methods for Amino Acid Analysis in Natural Products.

We validate the improved resolution and sensitivity of the C3 Marfey's method, including an ability to resolve all Ile isomers, against an array of amino acids commonly encountered in natural products and by comparison to an existing Marfey's method. We also describe an innovative 2D C3 Marfey's method as an analytical approach for determining the regiochemistry of enantiomeric amino acid residues in natural products. The C3 and 2D C3 Marfey's methods represent valuable tools for probing and defining the stereocomplexity of hydrolytically accessible amino acid residues in natural products.

Use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis for rapid confirmation of Burkholderia pseudomallei in septicemic melioidosis.

Burkholderia pseudomallei was quickly identified from blood cultures collected from septicemic patients by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis using an in-house reference library. This procedure reduced the time to definitive identification by more than 24 hours. This analysis is a useful addition to laboratory methods for early recognition of septicemic melioidosis in non-endemic settings.

Cottoquinazoline A and cotteslosins A and B, metabolites from an Australian marine-derived strain of Aspergillus versicolor.

An Australian marine-derived isolate of Aspergillus versicolor (MST-MF495) yielded the known fungal metabolites sterigmatocystin, violaceol I, violaceol II, diorcinol, (-)-cyclopenol, and viridicatol, along with a new alkaloid, cottoquinazoline A (1), and two new cyclopentapeptides, cotteslosins A (2) and B (3). Structures for 1-3 and the known compounds were determined by spectroscopic analysis. The absolute configurations of 1-3 were addressed by chemical degradation and application of the C(3) Marfey's method.

Acremolides A-D, lipodepsipeptides from an Australian marine-derived fungus, Acremonium sp.

An Australian estuarine isolate of an Acremonium sp. (MST-MF588a) yielded the two known compounds 19- O-acetylchaetoglobosin D ( 1) and 19- O-acetylchaetoglobosin B ( 2), as the sole cytotoxic principles, along with the known aromatic metabolite RKB 3564S ( 3), and a novel family of lipodepsipeptides, acremolides A-D ( 4- 7). Structures were assigned to 4- 7 on the basis of detailed spectroscopic analysis and chemical derivatization and by application of a new C 3 Marfey's method for amino acid analysis.