Fungal pigments inhibit the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of darkly pigmented fungi
Fungal pigments inhibit the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of darkly pigmented fungi
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DOI：
10.1016/j.ab.2010.11.025
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发表时间：
2011-04-01
影响因子：
2.9
通讯作者：
Beezhold, Donald H.
中科院分区：
文献类型：
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作者：
Buskirk, Amanda D.;Hettick, Justin M.;Beezhold, Donald H.
基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）已被用来区分念珠状真菌物种，然而，深色色素真菌产生差的指纹质谱，包含几个低相对丰度的峰。在这项研究中，深色真菌色素对所观察到的MALDI质谱的影响进行了研究。通过MALDI-TOF和MALDI-qTOF（四极TOF）MS分析含有不同浓度的从尼日尔提取的合成黑色素或真菌色素的肽和蛋白质样品。在含有大于250 ng/μ l色素的样品中观察到信号抑制。MALDI样品存款的显微镜检查通常是不均匀的，高色素浓度的区域显示为黑色。从样品存款的这些深色着色区域获取MALDI质谱产生差的或没有[M+H]（+）离子信号。与此相反，在样品存款和菌丝阴性对照提取物A.尼日尔没有受到抑制。这项研究表明，深色真菌色素抑制解吸/电离过程中MALDI-MS，然而，这些真菌可以成功地分析MALDI-TOF MS时，抑制色素表达的培养方法。向真菌生长培养基中添加三环唑阻断真菌黑色素合成，并产生较少黑化的真菌，其可通过MALDI-TOF MS进行分析。
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used to discriminate moniliaceous fungal species; however, darkly pigmented fungi yield poor fingerprint mass spectra that contain few peaks of low relative abundance. In this study, the effect of dark fungal pigments on the observed MALDI mass spectra was investigated. Peptide and protein samples containing varying concentrations of synthetic melanin or fungal pigments extracted from Aspergillus niger were analyzed by MALDI-TOF and MALDI-qTOF (quadrupole TOF) MS. Signal suppression was observed in samples containing greater than 250 ng/mu l pigment. Microscopic examination of the MALDI sample deposit was usually heterogeneous, with regions of high pigment concentration appearing as black. Acquisition of MALDI mass spectra from these darkly pigmented regions of the sample deposit yielded poor or no [M+H](+) ion signal. In contrast, nonpigmented regions within the sample deposit and hyphal negative control extracts of A. niger were not inhibited. This study demonstrated that dark fungal pigments inhibited the desorption/ionization process during MALDI-MS; however, these fungi may be successfully analyzed by MALDI-TOF MS when culture methods that suppress pigment expression are used. The addition of tricyclazole to the fungal growth media blocks fungal melanin synthesis and results in less melanized fungi that may be analyzed by MALDI-TOF MS. Published by Elsevier Inc.