Fungal-Induced Deterioration of Mural Paintings: In Situ and Mock-Model Microscopy Analyses.

Fungal deterioration of frescoes was studied in situ on a selected Serbian church, and on a laboratory model, utilizing standard and newly implemented microscopy techniques. Scanning electron microscopy (SEM) with energy-dispersive X-ray confirmed the limestone components of the plaster. Pigments used were identified as carbon black, green earth, iron oxide, ocher, and an ocher/cinnabar mixture. In situ microscopy, applied via a portable microscope ShuttlePix P-400R, proved very useful for detection of invisible micro-impairments and hidden, symptomless, microbial growth. SEM and optical microscopy established that observed deterioration symptoms, predominantly discoloration and pulverization of painted layers, were due to bacterial filaments and fungal hyphal penetration, and formation of a wide range of fungal structures (i.e., melanized hyphae, chlamydospores, microcolonial clusters, Cladosporium-like conidia, and Chaetomium perithecia and ascospores). The all year-round monitoring of spontaneous and induced fungal colonization of a "mock painting" in controlled laboratory conditions confirmed the decisive role of humidity level (70.18±6.91% RH) in efficient colonization of painted surfaces, as well as demonstrated increased bioreceptivity of painted surfaces to fungal colonization when plant-based adhesives (ilinocopie, murdent), compared with organic adhesives of animal origin (bone glue, egg white), are used for pigment sizing.

Mycobiome Diversity of the Cave Church of Sts. Peter and Paul in Serbia-Risk Assessment Implication for the Conservation of Rare Cavern Habitat Housing a Peculiar Fresco Painting.

The mycobiome of the cave Church of Sts. Peter and Paul, housing the peculiar fresco painting of "The Bald-headed Jesus", was analyzed via culture-dependent and -independent methods. Salt efflorescence, colored patinas, and biofilm, as well as biopitting, discolorations, and fruiting bodies of wood-decay fungi were observed on surfaces within the church. Microscopic analyses showed an abundance of fungal structures, i.e., conidiophores, conidia, chlamydospores, and ascospores. The estimated values of the contamination classified all surfaces as the "Danger zone". A total of 24 fungi from 17 genera were determined as part of the culturable mycobiome, with a dominance of Ascomycota of genera Penicillium. Biodegradative profiles analyzed via plate assays demonstrated positive reactions for 16 isolates: most commonly acid production (8), followed by pigment production and ligninolytic activity (6), protein degradation (5), cellulolytic activity (3) and carbonate dissolution (2). Metabarcoding analysis showed a dominance of Ascomycota in all samples (79.9−99.7%), with high relative abundance documented for Hypoxylon fuscopurpureum on the iconostasis and unclassified Mycosphaerellaceae family within order Capnodiales on fresco and stone, as well as moderate relative abundance for unclassified Dothideomycetes, Botryolepraria lesdainii, Verrucaria sp. and Cladosporium sp. on stone walls. The used set of integrative methods pointed out species of genus Neodevriesia and H. fuscopurpureum as the main deteriogenic agents of fresco and iconostasis surfaces, respectively.

ATP bioluminescence method: tool for rapid screening of organic and microbial contaminants on deteriorated mural paintings.

The extent of the microbial contamination of the seventeenth-century wall paintings in the nave of the old Church of the Holy Ascension (Veliki Krcimir, Serbia) was evaluated via newly implemented ATP bioluminescence method, and traditional cultivation-based method, utilising commercially available dip slides. To assess the validity of ATP, as a biomarker for rapid detection of mural surface contamination, obtained zones of cleanliness values, in range from 1.0 to 5.3, were compared to documented total microbial counts, ranging between seven and 247 CFU/cm2. Small coefficients of determination, 0.0106-0.0385, suggest poor correlation between microbial counts and surface ATP levels; however, zones of cleanliness values are of great help in determining the high points of contamination, aka 'hotspots', which should be given special attention during sampling and investigation using other methods. In addition, various aspects of the possible implementation of the ATP bioluminescence method in an integrated system of wall painting conservation are discussed.

Seasonal diversity of biodeteriogenic, pathogenic, and toxigenic constituents of airborne mycobiota in a sacral environment.

The main purpose of this study was to isolate airborne fungi and assess seasonal variations in air contamination with their particulates by determining the levels of their propagules in the nave and exonarthex of a church. We also monitored indoor microclimate as a determining factor for fungal proliferation on wall paintings, spore release, and transmission through the air. The temperature and relative humidity of the nave favoured fungal growth. A total of 33 fungi were isolated, mainly of the phylum Ascomycota, and to the lesser extent of the phyla Zygomycota and Basidiomycota. The most common were the fungi of the genera Penicillium and Aspergillus (23.55 % and 20.58 %, respectively). Sørensen's quotient of similarity (0.37) suggests moderate species overlap and constant exchange of fungal propagules between the nave and exonarthex. The autumn had the highest diversity, with 17 documented taxa, followed by the summer and the winter. The spring had only eight taxa. Quantitative analysis of the airborne mycobiota in the nave (430±84.85 to 1880±106.07 CFU m-3) and exonarthex (715±59.62 to 2295±91.92 CFU m-3) showed very high contamination throughout the year, with values exceeding the maximum permissible concentrations by most standards. Many of the fungi determined in this study are known for their biodeteriogenic, toxigenic, and allergenic properties, and are a threat not only to occasional visitors and staff, but also to valuable works of art decorating nave walls.

Frankincense and myrrh essential oils and burn incense fume against micro-inhabitants of sacral ambients. Wisdom of the ancients?

ETHNOPHARMACOLOGICAL RELEVANCE: Essential oils obtained from resins of Boswellia carteri Birdw. and Commiphora myrrha (Nees) Engl., commonly known as frankincense and true myrrh respectively, have been used extensively since 2800 BCE for the treatment of skin sores, wounds, teeth, inflammation, and urinary tract diseases in traditional medicine; for preparation of mummification balms and unguents; and also as incense and perfumes. Since ancient times, burning of frankincense and myrrh in places of worship for spiritual purposes and contemplation (a ubiquitous practice across various religions) had hygienic functions, to refine the smell and reduce contagion by purifying the indoor air. AIM OF THE STUDY: The general purpose of the study was to assess the in vitro antimicrobial potential of the liquid and vapour phases of B. carteri and C. myrrha essential oils and burn incense, as well as to test the effectiveness of their in situ application to cleanse microbially-contaminated air within the ambient of an investigated 17th-century church. MATERIALS AND METHODS: The chemical composition of B. carteri and C. myrrha essential oils, obtained by hydrodistillation of frankincense and true myrrh oleo gum resins was determined using GC/MS, and antimicrobial properties of their liquid and vapour phases were assessed by the broth microdilution and microatmosphere diffusion methods. Chemical analysis of burn incense fume obtained using bottle gas washing with dichloromethane as a solvent was performed by GC/MS, while its antimicrobial activity was evaluated using a modified microatmosphere diffusion method to evaluate germination inhibition for fungi and CFU count reduction for bacteria. The in situ antimicrobial activity of B. carteri burn incense and essential oil vapour phase was assessed in the sealed nave and diaconicon of the church, respectively. RESULTS: The dominant compounds of B. carteri EO were α-pinene (38.41%) and myrcene (15.21%), while C. myrrha EO was characterized by high content of furanoeudesma-1,3-diene (17.65%), followed by curzerene (12.97%), ß-elemene (12.70%), and germacrene B (12.15%). Burn incense fume and soot had α-pinene (68.6%) and incensole (28.6%) as the most dominant compounds, respectively. In vitro antimicrobial assays demonstrated high bacterial and fungal sensitivity to the liquid and vapour phases of EOs, and burn incense fume. In situ application of B. carteri EO vapour and incense fume resulted in reduction of air-borne viable microbial counts by up to 45.39 ±â€¯2.83% for fungi and 67.56 ±â€¯3.12% for bacteria (EO); and by up to 80.43 ±â€¯2.07% for fungi and 91.43 ±â€¯1.26% for bacteria (incense fume). CONCLUSIONS: The antimicrobial properties of essential oil derived from frankincense, a compound with well-known traditional use, showed that it possesses a clear potential as a natural antimicrobial agent. Moreover, the results suggest possible application of B. carteri EO vapour and incense fume as occasional air purifiers in sacral ambients, apart from daily church rituals.