Gruenwald Maike, Rabenstein Andreas, Remesch Markko, Kuever Jan
Bremen Institute for Materials Testing, Microbiology Department, Paul-Feller-Straße 1, 28199 Bremen, Germany.
J Microbiol Methods. 2015 Aug;115:83-8. doi: 10.1016/j.mimet.2015.05.025. Epub 2015 May 31.
Stachybotrys chartarum and Stachybotrys chlorohalonata are two closely related species. Unambiguous identification of these two species is a challenging task if relying solely on morphological criteria and therefore smarter and less labor-intensive approaches are needed. Here we show that even such closely related species of fungi as S. chartarum and S. chlorohalonata are unequivocally discriminated by their highly reproducible MALDI-TOF-MS fingerprints (matrix assisted laser desorption/ionization time-of-flight mass spectrometry fingerprints). We examined 19 Stachybotrys and one Aspergillus isolate by MALDI-TOF-MS. All but one isolate produced melanin containing conidia on malt extract agar. Mass spectra were obtained in good quality from the analysis of hyaline and darkly pigmented conidia by circumventing the property of melanin which causes signal suppression. MALDI-TOF fingerprint analysis clearly discriminated not only the two morphologically similar species S. chartarum and S. chlorohalonata from each other but separated them precisely from Stachybotrys bisbyi and Aspergillus versicolor isolates. Furthermore, even S. chartarum chemotypes A and S could be differentiated into two distinct groups by their MALDI-TOF fingerprints. The chemotypes of S. chartarum isolates were identified by trichodiene synthase 5 (tri5) sequences prior to mass spectra analysis. Additionally, species identities of all isolates were verified by their 18S rRNA and tri5 gene sequences.
暗黑曲霉和嗜盐暗黑曲霉是两个密切相关的物种。如果仅依靠形态学标准，明确鉴定这两个物种是一项具有挑战性的任务，因此需要更智能且劳动强度较小的方法。在这里，我们表明，即使是像暗黑曲霉和嗜盐暗黑曲霉这样密切相关的真菌物种，也可以通过其高度可重复的基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF-MS）指纹图谱明确区分。我们通过MALDI-TOF-MS检测了19株暗黑曲霉和1株曲霉分离株。除了一株分离株外，所有分离株在麦芽提取物琼脂上都产生了含黑色素的分生孢子。通过规避导致信号抑制的黑色素特性，从透明和深色分生孢子的分析中获得了高质量的质谱图。MALDI-TOF指纹分析不仅清楚地将形态相似的暗黑曲霉和嗜盐暗黑曲霉这两个物种区分开来，而且将它们与比斯比暗黑曲霉和杂色曲霉分离株精确区分。此外，即使是暗黑曲霉的化学型A和S也可以通过其MALDI-TOF指纹图谱分为两个不同的组。在进行质谱分析之前，通过trichodiene合酶5（tri5）序列鉴定了暗黑曲霉分离株的化学型。此外，所有分离株的物种身份通过其18S rRNA和tri5基因序列进行了验证。
