Dereplicating and Spatial Mapping of Secondary Metabolites from Fungal Cultures in Situ

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• 作者：Vincent P. Sica ; Huzefa A. Raja ; Tamam El-Elimat ; Vilmos Kertesz ; Gary J. Van Berkel ; Cedric J. Pearce ; Nicholas H. Oberlies
• 刊名：Journal of Natural Products
• 出版年：2015
• 出版时间：August 28, 2015
• 年：2015
• 卷：78
• 期：8
• 页码：1926-1936
• 全文大小：636K
• ISSN：1520-6025

文摘

Ambient ionization mass spectrometry techniques have recently become prevalent in natural product research due to their ability to examine secondary metabolites in situ. These techniques retain invaluable spatial and temporal details that are lost through traditional extraction processes. However, most ambient ionization techniques do not collect mutually supportive data, such as chromatographic retention times and/or UV/vis spectra, and this can limit the ability to identify certain metabolites, such as differentiating isomers. To overcome this, the droplet鈥搇iquid microjunction鈥搒urface sampling probe (droplet鈥揕MJ鈥揝SP) was coupled with UPLC鈥揚DA鈥揌RMS鈥揗S/MS, thus providing separation, retention times, MS data, and UV/vis data used in traditional dereplication protocols. By capturing these mutually supportive data, the identity of secondary metabolites can be confidently and rapidly assigned in situ. Using the droplet鈥揕MJ鈥揝SP, a protocol was constructed to analyze the secondary metabolite profile of fungal cultures without any sample preparation. The results demonstrate that fungal cultures can be dereplicated from the Petri dish, thus identifying secondary metabolites, including isomers, and confirming them against reference standards. Furthermore, heat maps, similar to mass spectrometry imaging, can be used to ascertain the location and relative concentration of secondary metabolites directly on the surface and/or surroundings of a fungal culture.