Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark.
Appl Microbiol Biotechnol. 2018 Oct;102(19):8477-8491. doi: 10.1007/s00253-018-9213-0. Epub 2018 Jul 11.
Cereals are vulnerable substrates for fungal growth and subsequent mycotoxin contamination. One of the major fungal genera to colonize the ecosystem of stored grain is Penicillium, especially species in the series of Viridicata and Verrucosa. Culturing these species on grains, we hoped to induce the production of relevant secondary metabolites produced by these fungi in the early stage of cereal breakdown. In a multivariate setup six different cereal grains (wheat, rye, barley, oat, rice, and maize), one kind of white beans, and two standard fungal media, Yeast Extract Sucrose agar (YES agar) and Czapek Yeast Autolysate agar (CYA agar), were inoculated with the ten most important cereal-associated species from Penicillium (P. aurantiogriseum, P. cyclopium, P. freii, P. melanoconidium, P. neoechinulatum, P. polonicum, P. tricolor, P. viridicatum, P. hordei, and P. verrucosum). P. nordicum is a meat-associated species, which was included due to its chemical association with P. verrucosum, in addition to see if a substrate change would alter the profile of known chemistry. We found that cereals function very well as substrates for secondary metabolite production, but did not present significantly different secondary metabolite profiles, concerning known chemistry, as compared to standard laboratory agar media. However, white beans altered the semi-quantitative secondary metabolite profiles for several species. Correlations between substrates and certain metabolites were observed, as illuminated by principal component analysis. Many bioactive secondary metabolites were observed for the first time in the analyzed fungal species, including ergot type alkaloids in P. hordei.
谷物是真菌生长和随后产生真菌毒素污染的脆弱基质。在定殖储存谷物生态系统的主要真菌属中，有一种是青霉属，尤其是青霉属的 Viridicata 和 Verrucosa 系列。我们在谷物上培养这些物种，希望在谷物分解的早期阶段诱导这些真菌产生相关的次生代谢产物。在一个多元设置中，六种不同的谷物（小麦、黑麦、大麦、燕麦、大米和玉米）、一种白豆和两种标准真菌培养基（酵母提取物蔗糖琼脂（YES 琼脂）和察氏酵母自溶琼脂（CYA 琼脂））被接种了青霉属中十种最重要的与谷物相关的物种（P. aurantiogriseum、P. cyclopium、P. freii、P. melanoconidium、P. neoechinulatum、P. polonicum、P. tricolor、P. viridicatum、P. hordei 和 P. verrucosum）。P. nordicum 是一种与肉类相关的物种，由于它与 P. verrucosum 的化学关联，除了观察底物变化是否会改变已知化学物质的特征外，我们也将其包括在内。我们发现，谷物作为次生代谢产物产生的基质非常有效，但与标准实验室琼脂培养基相比，就已知化学物质而言，它们并没有呈现出明显不同的次生代谢产物特征。然而，白豆改变了几种物种的半定量次生代谢产物特征。通过主成分分析观察到了底物和某些代谢物之间的相关性。在分析的真菌物种中观察到了许多生物活性次生代谢产物，包括 P. hordei 中的麦角生物碱。
