COMMUNITY

Literature from the Tikuna/Magüta culture, from the Amazon Forest, suggests the use of chemical reactions between the juice of the naīcü fruit and iron to produce a blue colorant still unknown among technical art historians and conservation scientists.

Until recently, the identification of the species of origin for skin and fur materials used in theproduction of archaeological clothing has been based on the analysis of macro‑ and microscopicmorphological features and on the traditional knowledge of Indigenous groups. This approach,however, is not always applicable due to the deterioration of the archaeological objects.Paleoproteomics was used as an alternative approach to identify the species of origin of fifteensamples of various tissues from approximately 600‑year‑old garments found in Nuulliit, northernGreenland. Proteomics revealed that a limited group of marine and terrestrial mammals were usedfor clothing production. The results obtained from the analysis of multiple types of clothing andelements, such as sinew thread and gut skin, suggest that their applications were based on theirproperties. When conclusive assignment of a sample to a species via proteomics was not possible, theobservation by transmitted light microscopy of feather and hair micromorphology, if not affected bydiagenesis, was used to improve the identification. The proteomic characterization of animal materialsused for clothing production in the Nuulliit archaeological context provides an insight into thepractical knowledge and the strategies adopted by the local Indigenous community to exploit naturalresources

As part of a long-term campaign to document, study, and conserve the Heroes tapestries from The Cloisters collection at The Metropolitan Museum of Art, organic colorant analysis of Julius Caesar (accession number 47.101.3) was performed. Analysis with liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-qToF-MS) revealed the presence of several multiply chlorinated xanthones produced only by certain species of lichen. Various lichen dye sources have been documented in the literature for centuries and are classified as either ammonia fermentation method (AFM) or boiling water method (BWM) dyes based on their method of production. However, none of these known sources produce the distinctive metabolites present in the tapestry. LC-qToF-MS was also used to compare the chemical composition of the dyes in the tapestry with that of several species of crustose lichen. Lichen metabolites, including thiophanic acid and arthothelin, were definitively identified in the tapestry based on comparison with lichen xanthone standards and a reference of Lecanora sulphurata, confirming the presence of a lichen source. This finding marks the first time that lichen xanthones have been identified in a historic object and the first evidence that BWM lichen dyes may have been used prior to the eighteenth century.

Ivory is a highly prized material in many cultures since it can be carved into intricate designs and have a highly polished surface. Due to its popularity, the animals from which ivory can be sourced are under threat of extinction. Identification of ivory species is not only important for CITES compliance, it can also provide information about the context in which a work was created. Here, we have developed a minimally invasive workflow to remove minimal amounts of material from precious objects and, using high-resolution mass spectrometry–based proteomics, identified the taxonomy of ivory and bone objects from The Metropolitan Museum of Art collection dating from as early as 4000 B.C. We built a proteomic database of underrepresented species based on exemplars from the American Museum of Natural History, and proposed alternative data analysis workflows for samples containing inconsistently preserved organic material. This application demonstrates extensive ivory species identification using proteomics to unlock sequence uncertainties, e.g., Leu/Ile discrimination.

Microbial communities reside at the interface between humans and their environment. Whether the microbiome can be leveraged to gain information on human interaction with museum objects is unclear. To investigate this, we selected objects from the Museum für Naturkunde and the Pergamonmuseum in Berlin, Germany, varying in material and size. Using swabs, we collected 126 samples from natural and cultural heritage objects, which were analyzed through 16S rRNA sequencing. By comparing the microbial composition of touched and untouched objects, we identified a microbial signature associated with human skin microbes. Applying this signature to cultural heritage objects, we identified areas with varying degrees of exposure to human contact on the Ishtar gate and Sam'al gate lions. Furthermore, we differentiated objects touched by two different individuals. Our findings demonstrate that the microbiome of museum objects provides insights into the level of human contact, crucial for conservation, heritage science, and potentially provenance research.

The exceptional and exciting occurrence of organic food residues inside large nineteenth century alkaline-glazed stoneware vessels from the Old Edgefield district, some also signed by enslaved potter and poet David Drake, has offered a unique opportunity to study those residues as anthropological evidence of the jars’ contents (e.g., preserved meat, fat, eggs, etc.), potentially offering information on the use of the jars and the lifestyle of the people that used them. Residues scraped from the jars’ surfaces were analyzed in the Department of Scientific Research of The Met to evaluate their composition, assess contaminations and clues to their condition (e.g., presence and extent of degradation products), all informing of the next process to further characterize the residue.

As part of the exhibition, Hear Me Now: The Black Potters of Old Edgefield, South Carolina, The Met’s Department of Scientific Research (DSR) investigated organic food residues found inside large nineteenth-century alkaline-glazed stoneware vessels from the Old Edgefield District, South Carolina. “Examining Storage Jars from the American South” describes the driving questions about the jars’ use and the users’ lifestyle. Investigations reported in “The Inside (and Outside) Scoop: Scientific Analysis of Food Residues Inside the Jars from Old Edgefield, South Carolina” established that the heterogeneous residues are mostly oily materials with solid materials of various unknown origins. We hoped to gain more information about the jars’ contents from these residues, but to do so we need the sophisticated tools and expertise of our collaborators through ARCHE.

Little is known about structural alterations of proteins within the polymeric films of paints. For the first time, hydrogen‑deuterium exchange mass spectrometry (HDX-MS) was implemented to explore the conformational alterations of proteins resulting from their interaction with inorganic pigments within the early stages of the paint film formation. Intact protein analysis and bottom-up electrospray-ionisation mass spectrometry strategies combined with progressively increasing deuterium incubation times were used to compare the protein structures of the model protein hen egg-white lysozyme (HEWL) extracted from newly dried non-pigmented films and newly dried films made from a freshly made mixture of HEWL with lead white pigment (2PbCO3 Pb(OH)2). The action of other pigments was also investigated, expanding the HDX study with a global approach to paint models of HEWL mixed with zinc white (ZnO), cinnabar (HgS) and red lead (Pb3O4) pigments. The results show structural modifications of HEWL induced by the interaction with the pigment metal ions during the paint formulation after drying and prior to ageing. Both the charge distribution of HEWL proteoforms, its oxidation rate and its deuterium absorption rate, were influenced by the pigment type, providing the first insights into the correlation of pigment type/metal cation to specific chemistries related to protein stability.

Biocodicology, the study of the biological information stored in manuscripts, ofers the possibility of interrogating manuscripts in novel ways. Exploring the biological data associated to parchment documents will add a deeper level of understanding and interpretation to these invaluable objects, revealing information about book production, livestock economies, handling, conservation and the historic use of the object. As biotechnological methods continue to improve we hope that biocodicology will become a highly relevant discipline in manuscript studies, contributing an additional perspective to the current scholarship. We hope that this review will act as a catalyst enabling further interactions between the heritage science community, manuscript scholars, curators and conservators.