Microstratigraphic, lipid biomarker and stable isotope study of a middle Palaeolithic combustion feature from Axlor, Spain.

Archaeological research has increasingly focused on studying combustion features as valuable sources of information regarding past technological and cultural aspects. The use of microstratigraphic and biomolecular techniques enables the identification of combustion residues and substrate components, and infer about past fire-related activities and the environments. Our study conducted on a combustion feature (Level N, ∼100 Ka) at the Axlor cave, a Middle Paleolithic site in northern Iberia, exemplifies the interdisciplinary approach to combustion features. Micromorphological features revealed depositional activities associated with occupations such as hearth rake-out and trampling. Through molecular (n-alkanes, n-alcohols, and n-fatty acids) and isotopic analysis (δ13C16:0 and δ13C18:0), we infer the good preservation of organic matter, the contributions of non-ruminant fats, and the dead-wood gathering strategies by Neanderthal groups. By combining microstratigraphic and biomolecular approaches, our study significantly contributes to the advancement of our current understanding of Neanderthal pyrotechnology.

Curated cauldrons: Preserved proteins from early copper-alloy vessels illuminate feasting practices in the Caucasian steppe.

Large metal and metal-alloy cauldrons first appear on the far western steppe and Caucasus region during the Maykop period (3700-2900 BCE); however, the types of foods or beverages cooked in and served from these vessels have remained mysterious. Here, we present proteomic analysis of nine residues from copper-alloy cauldrons from Maykop burial contexts where we identify muscle, blood, and milk proteins specific to domesticated, and possibly wild, ruminants. This study clearly demonstrates that the earliest, large-volume feasting vessels contained both primary and secondary animal products, likely prepared in the form of a stew.

Preservation of whole antibodies within ancient teeth.

Archaeological remains can preserve some proteins into deep time, offering remarkable opportunities for probing past events in human history. Recovering functional proteins from skeletal tissues could uncover a molecular memory related to the life-history of the associated remains. We demonstrate affinity purification of whole antibody molecules from medieval human teeth, dating to the 13th-15th centuries, from skeletons with different putative pathologies. Purified antibodies are intact retaining disulphide-linkages, are amenable to primary sequences analysis, and demonstrate apparent immunoreactivity against contemporary EBV antigen on western blot. Our observations highlight the potential of ancient antibodies to provide insights into the long-term association between host immune factors and ancient microbes, and more broadly retain a molecular memory related to the natural history of human health and immunity.

Four billion years of microbial terpenome evolution.

Terpenoids, also known as isoprenoids, are the largest and most diverse class of organic compounds in nature and are involved in many membrane-associated cellular processes, including membrane organization, electron transport chain, cell signaling, and phototrophy. Terpenoids are ancient compounds with their origin presumably before the last universal common ancestor. However, Bacteria and Archaea are known to possess two distinct terpenoid repertoires and utilize terpenoids differently. Most notably, archaea constitute their cellular membrane solely made of terpenoid-based phospholipids, contrary to the bacterial membrane that consists of fatty acid-based phospholipids. Thus, the composition of ancestral membranes at the beginning of cellular life and the diversification of terpenoids in early life remain enigmatic. This review addresses these key issues through comprehensive phylogenomic analyses of extant terpenoid biosynthesis enzymes in Bacteria and Archaea. We aim to infer the basal components of terpenoid biosynthesis machinery that have an ancient origin before the divergence of the two domains and shed light on the deep evolutionary connection between terpenoid biochemistry and early life.