Fig 1.
Carlo Bononi, Incoronazione della Vergine.
1616–1620, oil on canvas, 280 cm in diameter, Ferrara, Basilica of Santa Maria in Vado: a) painting (sampling points are indicated by asterisks, *); b) damage due to biodegradation (verso); c) craquelures network; d) lacerations, deformations, and gaps corresponding to the cloth stitching (recto). Details of the damage are reported on the side. Reprinted from http://www.museoinvita.it/lincoronazione-della-vergine-di-carlo-bononi/ under a CC BY license, with permission from “MuseoinVita” biannual journal, original copyright 2018.
Table 1.
Temperature (T, C°) and carbon dioxide (CO2, ppm) values detected at different areas of the painting.
Fig 2.
Cross-section of the sample collected from the red clothing of the Virgin, showing several overlapped pictorial layers.
a) image obtained by optical microscopy (original magnification 80X), layers are indicated by the numbers 1–6, indicating the preparatory layer (1), white layer (2, 4), blue layer (3), red layer (5), and covering varnish (6); b) elemental chemical map obtained by SEM-EDS analysis. Individual chemical elements are indicated by specific colors (Al, red; Cu, blue; Pb, green, S, grey, Ca, yellow). Numbers 1–5 indicate the preparatory layer (1), white layer (2, 4), blue layer (3), and red layer (5).
Fig 3.
OM analysis of molds isolated from the recto of the painting.
Photomicrographs show: a) conidial heads of Aspergillus spp. (original magnification 100X); b) conidial heads of Penicillium spp. (original magnification 100X); c) elliptical conidia ascribable to Cladosporium spp. (original magnification 100X); d) club-shaped and septate spores of Alternaria spp. (original magnification 100X).
Fig 4.
SEM analysis of molds isolated from the recto of the painting.
Microphotographs show: a) conidial heads of Aspergillus spp. (magnification 6.46 KX); b) conidial heads of Penicillium spp. (magnification 3.11 KX); c) elliptical conidia ascribable to Cladosporium spp. (magnification 6.41 KX); d) club-shaped and septate spores of Alternaria spp. (magnification 9.14 KX).
Fig 5.
SEM photomicrographs of conidia of Aspergillus species with different wall ornamentations.
a) conidia with a smooth surface detected on samples taken from a light-colored area (magnitude 10.21 KX), b) conidia with a slightly rough surface (typical of A. ochraceus) identified on samples collected from a dark-brown area (magnitude 15.36 KX).
Fig 6.
SEM photomicrographs of mycogenic minerals tangled in fungal hyphae.
Original magnification a) 8.07 kx and b) 18.28 kx. The crystals were detected in samples taken from the side of the painting touching the basilica floor.
Fig 7.
Bacteria detected on the painting.
Samples were collected from the recto (a, b, c) and the verso (d, e, f) of the painting. a) colonies of Staphylococcus spp. on a Mego agar plate; b) the same Staphylococcus spp. viewed by OM after Gram staining (original magnification 100X) and c) by SEM. d) colonies of Bacillus spp. on a TSA agar plate; e) the same Bacillus spp. viewed by OM after Gram staining (original magnification 100X) and f) SEM.
Fig 8.
Effectiveness of a probiotic compound at inhibiting the growth of microorganisms contaminating the painting.
Molds and bacteria were isolated from the painting as described in the methods. Each individual species was incubated in TSB at room temperature for 24 hours under mild agitation and then spread on TSA plates in the presence or absence of an equal amount of the probiotic product. The growth of contaminating microorganisms was evaluated after 2–5 days of incubation at room temperature. The results shown are those obtained after 5 days of incubation and are representative of three independent experiments.