Muñoz Alma Hortensia Serafin, Kubachka Kevin, Wrobel Kazimierz, Corona Felix Gutierrez, Yathavakilla Santha K V, Caruso Joseph A, Wrobel Katarzyna
Instituto de Investigaciones Científicas, Universidad de Guanajuato, Mexico.
J Agric Food Chem. 2005 Jun 29;53(13):5138-43. doi: 10.1021/jf0505933.
Huitlacoche is the ethnic name of the young fruiting bodies of Ustilago maydis, a common parasite of maize. In Mexico and other Latin American countries, this fungus has been traditionally appreciated as a local delicacy. In this work a metallomics approach was used with the determination of eight elements in huitlacoche by electrothermal atomic absorption spectrometry as one facet of this approach. The results obtained indicated relatively lower concentrations of commonly analyzed metals, as referred to the data reported for other mushroom types. This effect was ascribed to different accessibilities of elements, depending on fungus substrate (lower from plant than from soil). Subcellular fractionation was accomplished by centrifugation of cell homogenates suspended in Tris-HCl buffer. Recoveries of the fractionation procedure were in the range of 71-103%. For six elements (Cr, Cu, Fe, Mn, Ni, and Pb), the mean relative contributions in cytosol, cell walls, and mixed membrane fraction were 50.7, 48.2, and 1.1% respectively. To attain the molecular weight distribution of compounds containing target elements as an additional aspect of the metallomics approach, the fungus extract (1% sodium dodecyl sulfate in Tris-HCl, 30 mmol L(-)(1), pH 7.0) was analyzed by size exclusion chromatography with UV and ICP-MS detection. With spectrophotometric detection (280 nm), the elution of high molecular weight compounds was observed in the form of one peak (MW > 10 kDa), and several lower peaks appeared at higher retention times (MW < 10 kDa). On ICP-MS chromatograms, a coelution of (59)Co, (63)Cu, (57)Fe, (202)Hg, (60)Ni, and (80)Se with the first peak on the UV chromatogram was clearly observed, indicating that a fraction of each element incorporated with high molecular weight compounds (12.7, 19.8, 33.7, 100, 19.4, and 45.8%, respectively, based on the peak area measurements). From a comparison of (80)Se and (33)S chromatograms (for sulfur analysis, the extract was obtained in the absence of SDS), both elements coeluted with the first UV peak, but their lower molecular weight compounds were apparently different. These findings may contribute to a better understanding of the accumulation of elements in mushrooms.
玉米黑粉菌是玉米黑粉菌（Ustilago maydis）幼嫩子实体的民族名称，玉米黑粉菌是玉米常见的寄生菌。在墨西哥和其他拉丁美洲国家，这种真菌传统上被视为当地的美味佳肴。在这项工作中，采用了金属组学方法，用电热原子吸收光谱法测定玉米黑粉菌中的8种元素，作为该方法的一个方面。所得结果表明，与其他蘑菇类型报道的数据相比，常见分析金属的浓度相对较低。这种效应归因于元素的不同可及性，这取决于真菌的底物（从植物中获取的元素比从土壤中获取的元素少）。通过将细胞匀浆悬浮在Tris-HCl缓冲液中进行离心来完成亚细胞分级分离。分级分离过程的回收率在71-103%范围内。对于六种元素（铬、铜、铁、锰、镍和铅），在细胞质、细胞壁和混合膜部分的平均相对贡献率分别为50.7%、48.2%和1.1%。作为金属组学方法的另一个方面，为了获得含目标元素化合物的分子量分布，用紫外和电感耦合等离子体质谱检测的尺寸排阻色谱法分析真菌提取物（在Tris-HCl中1%十二烷基硫酸钠，30 mmol L⁻¹，pH 7.0）。通过分光光度检测（280 nm），观察到高分子量化合物以一个峰的形式洗脱（MW > 10 kDa），在较高保留时间出现几个较低的峰（MW < 10 kDa）。在电感耦合等离子体质谱色谱图上，清楚地观察到（⁵⁹）Co、（⁶³）Cu、（⁵⁷）Fe、（²⁰²）Hg、（⁶⁰）Ni和（⁸⁰）Se与紫外色谱图上的第一个峰共洗脱，表明每种元素的一部分与高分子量化合物结合（分别基于峰面积测量为12.7%、19.8%、33.7%、100%、19.4%和45.8%）。通过比较（⁸⁰）Se和（³³）S色谱图（用于硫分析，提取物在没有十二烷基硫酸钠的情况下获得），两种元素都与第一个紫外峰共洗脱，但它们较低分子量的化合物明显不同。这些发现可能有助于更好地理解蘑菇中元素的积累。
