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Amid the possible causes of a very famous foxing: molecular and microscopic insight into Leonardo da Vinci's self-portrait.

Authors :
Piñar G
Tafer H
Sterflinger K
Pinzari F
Source :
Environmental microbiology reports [Environ Microbiol Rep] 2015 Dec; Vol. 7 (6), pp. 849-59. Date of Electronic Publication: 2015 Aug 19.
Publication Year :
2015

Abstract

Leonardo da Vinci's self-portrait is affected by foxing spots. The portrait has no fungal or bacterial infections in place, but is contaminated with airborne spores and fungal material that could play a role in its disfigurement. The knowledge of the nature of the stains is of great concern because future conservation treatments should be derived from scientific investigations. The lack of reliable scientific data, due to the non-culturability of the microorganisms inhabiting the portrait, prompted the investigation of the drawing using non-invasive and micro-invasive sampling, in combination with scanning electron microscope (SEM) imaging and molecular techniques. The fungus Eurotium halophilicum was found in foxing spots using SEM analyses. Oxalates of fungal origin were also documented. Both findings are consistent with the hypothesis that tonophilic fungi germinate on paper metabolizing organic acids, oligosaccharides and proteic compounds, which react chemically with the material at a low water activity, forming brown products and oxidative reactions resulting in foxing spots. Additionally, molecular techniques enabled a screening of the fungi inhabiting the portrait and showed differences when different sampling techniques were employed. Swabs samples showed a high abundance of lichenized Ascomycota, while the membrane filters showed a dominance of Acremonium sp. colonizing the drawing.<br /> (© 2015 The Authors. Environmental Microbiology Reports published by Society for Applied Microbiology and John Wiley & Sons Ltd.)

Details

Language :
English
ISSN :
1758-2229
Volume :
7
Issue :
6
Database :
MEDLINE
Journal :
Environmental microbiology reports
Publication Type :
Academic Journal
Accession number :
26111623
Full Text :
https://doi.org/10.1111/1758-2229.12313