Istituto Centrale per il Restauro e la Conservazione del Patrimonio Archivistico e Librario, Via Milano 76, 00184, Rome, Italy.
Environ Microbiol. 2013 Apr;15(4):1050-62. doi: 10.1111/1462-2920.12027. Epub 2012 Nov 15.
Fungal biodeterioration of ivory was investigated with in vitro inoculation of samples obtained from boar and walrus tusks with the fungi Aspergillus niger and Serpula himantioides, species of known geoactive abilities. A combination of light and scanning electron microscopy together with associated analytical techniques was used to characterize fungal interactions with the ivory, including changes in ivory composition, dissolution and tunnelling, and the formation of new biominerals. The research was aimed at providing further understanding of the potential roles of fungi in the colonization and deterioration of ivory in terrestrial environments, but also contributes to our knowledge regarding the possible origins of the surface damage observed on early medieval sculptures made largely from walrus tusks, referred to as 'the Lewis hoard of gaming pieces', that were presumably produced for playing chess. The experiments have shown that the possibility of damage to ivory being caused by fungi is realistic. Scanning electron microscopy revealed penetration of fungal hyphae within cracks in the walrus tusk that showed also widespread tunnelling by fungal hyphae as well as 'fungal footprints' where the surface was etched as a consequence of mycelial colonization. Similar phenomena were observed with boar tusk ivory, while production of metabolites could lead to complete dissolution of the sample. Colonization of ivory and/or exposure to fungal activity lead to extensive secondary biomineral formation, and this was identified as calcium oxalate, mainly as the monohydrate, whewellite.
研究了从野猪和海象象牙中分离出的黑曲霉和鳞皮扇菌等具有已知地理活性能力的真菌对象牙的生物降解作用。采用光镜和扫描电子显微镜以及相关分析技术，研究了真菌与象牙的相互作用，包括象牙成分的变化、溶解和侵蚀以及新生物矿化的形成。这项研究旨在进一步了解真菌在陆地上象牙定殖和降解过程中的潜在作用，但也有助于我们了解在可能的起源上观察到的早期中世纪雕塑表面损伤的情况，这些雕塑主要由海象象牙制成，被称为“刘易斯游戏棋子宝藏”，据推测是为了玩国际象棋而制作的。实验表明，真菌可能会对象牙造成损害。扫描电子显微镜显示，真菌菌丝穿透了海象象牙的裂缝，并且广泛存在真菌菌丝的侵蚀以及“真菌足迹”，这是由于菌丝定殖导致表面被蚀刻。在野猪象牙中也观察到了类似的现象，而代谢产物的产生可能导致样品完全溶解。象牙的定殖和/或真菌活动的暴露导致广泛的次生生物矿化形成，这被鉴定为草酸钙，主要是一水合物，即尿酸钙。
