RESUMO
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.
Assuntos
Aminoácidos/análise , Produtos Biológicos/química , Alanina/análogos & derivados , Alanina/química , Sequência de Aminoácidos , Aminoácidos/química , Dinitrobenzenos , Estrutura Molecular , EstereoisomerismoRESUMO
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.
Assuntos
Burkholderia pseudomallei/isolamento & purificação , Melioidose/diagnóstico , Melioidose/microbiologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Antibacterianos/uso terapêutico , Austrália , Burkholderia pseudomallei/efeitos dos fármacos , Burkholderia pseudomallei/crescimento & desenvolvimento , Burkholderia pseudomallei/patogenicidade , Humanos , Masculino , Melioidose/tratamento farmacológico , Meropeném , Pessoa de Meia-Idade , Tienamicinas/uso terapêuticoRESUMO
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. The use of "cellophane raft" high-nutrient media as a device for up-regulating secondary metabolite diversity in marine-derived fungi is discussed. The antibacterial properties displayed by A. versicolor (MST-MF495) were attributed to the phenols violaceol I, violaceol II, and diorcinol, while cotteslosins 2 and 3 were identified as weak cytotoxic agents.
Assuntos
Antineoplásicos/isolamento & purificação , Aspergillus/química , Peptídeos Cíclicos/isolamento & purificação , Quinazolinas/isolamento & purificação , Antineoplásicos/química , Antineoplásicos/farmacologia , Austrália , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Biologia Marinha , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Quinazolinas/química , Quinazolinas/farmacologia , Esterigmatocistina/química , Esterigmatocistina/isolamento & purificaçãoRESUMO
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.