Project description:Tree ring features are affected by environmental factors and therefore are the basis for dendrochronological studies to reconstruct past environmental conditions. Oak wood often provides the data for these studies because of the durability particularly of oak heartwood and, hence the availability of samples spanning long time periods of the distant past. Wood formation is regulated in part by epigenetic mechanisms such as DNA methylation. Studies in the methylation state of DNA preserved in oak heartwood thus could identify epigenetic tree ring features informing on past environmental conditions. We investigated the feasibility of such studies using heartwood samples core-drilled from the trunks of standing oak trees spanning the AD 1776-2014. Heartwood contains little DNA, and large amounts of phenolic compounds known to hinder the preparation of high-throughput sequencing libraries. We sequenced whole-genome and DNA methylome libraries for oak heartwood up to 100 and 50 years of age, respectively. However, only 56 genomic regions with sufficient coverage for quantitative methylation analysis were identified, suggesting that the high-throughput sequencing of DNA will be in principal feasible for wood formed <100 years ago is impeded by the reduction in library complexity caused by the bisulfite treatment used to generate the oak methylome.
Project description:Archaeological dental calculus has emerged as a rich source of ancient biomolecules, including proteins. Previous analyses of proteins extracted from ancient dental calculus revealed the presence of the dietary milk protein β-lactoglobulin, providing direct evidence of dairy consumption in the archaeological record. However, the potential for calculus to preserve other food-related proteins has not yet been systematically explored. Here we analyse shotgun metaproteomic data from 100 archaeological dental calculus samples ranging from the Iron Age to the post-medieval period (8thC BC - 19thC AD) in Britain, as well as dental calculus from contemporary dental patients and recently deceased individuals, to characterise the range and extent of dietary proteins preserved in dental calculus. In addition to milk proteins, we detected proteomic evidence of foodstuffs such as cereals and plant products, as well as the digestive enzyme salivary amylase. We discuss the importance of optimized protein extraction methods, data analysis approaches, and authentication strategies in the identification of dietary proteins from archaeological dental calculus. Our ability to detect dietary proteins, although limited, demonstrates the potential of these methods to robustly identify foodstuffs in the archaeological record that are under-represented due to their poor preservation.
Project description:The origins, prevalence and nature of dairying have been long debated by archaeologists. Within the last decade, new advances in high-resolution mass spectrometry have allowed for the direct detection of milk proteins from archaeological remains, including ceramics, dental calculus, and preserved dairy products. Proteins recovered from archaeological remains are susceptible to post-excavation and laboratory contamination, a particular concern for ancient dairying studies as milk proteins are potential laboratory contaminants. Here, we examine how site-specific rates of deamidation can be used to elucidate patterns of peptide degradation, and authenticate ancient milk proteins. First, we characterize site-specific deamidation patterns in modern milk products and experimental samples, confirming that deamidation occurs primarily at low half-time sites. We then compare this to previously published ancient proteomic data from six studies reporting ancient milk peptides. We confirm that site-specific deamidation rates, on average, are more advanced in beta-lactoglobulin recovered from ancient dental calculus and pottery residues. Nevertheless, deamidation rates displayed a high degree of variability, making it challenging to authenticate samples with relatively few milk peptides. We demonstrate that site-specific deamidation is a useful tool for identifying modern contamination but highlight the need for multiple lines of evidence to authenticate ancient protein data.
Project description:Paget disease of bone (PDB) is a chronic skeletal disorder with contemporary cases characterised by one or a few affected bones in individuals over 55 years of age. PDB-like changes have been noted in archaeological remains as old as Roman although accurate diagnoses and knowledge of the natural history of ancient forms of the disease are lacking. Previous macroscopic and radiographic analyses of six skeletons from a collection of 130 excavated at Norton Priory in Cheshire, UK, and dating to late Medieval times, noted unusually extensive pathological changes resembling PDB affecting up to 75% of individual skeletons. Here we report the prevalence of the disease in the collection is also remarkably high (at least 15.8% of the adult sample) with age-at-death estimations as low as 35 years. Despite these profound phenotypic differences paleoproteomic analyses identified SQSTM1/p62 (p62), a protein central to the pathological milieu of classical PDB, as one of the few non-collagenous human sequences preserved in skeletal samples, indicating that the disorder was likely an ancient precursor of contemporary PDB. Western blotting indicated abnormal migration of ancient p62 protein, with subsequent targeted proteomic analyses detecting more than 60% of the p62 primary sequence and directing sequencing analyses of ancient DNA that excluded contemporary PDB-associated SQSTM1 mutations. Together our observations indicate the ancient p62 protein is likely modified within its C-terminal ubiquitin-associated (UBA) domain. Ancient miRNAs were also remarkably well preserved in an osteosarcoma from a skeleton with extensive disease, with miR-16 expression changes consistent with that reported in contemporary PDB-associated bone tumours. Our work demonstrates the potential of proteomics to inform diagnoses of ancient disease and supports the proposal that Medieval Norton Priory was a ‘hotspot’ for an ancient form of PDB, with unusual features presumably potentiated by as yet unidentified environmental or genetic factors.
Project description:Acute Oak Decline (AOD) is a decline-disease currently spreading in Britain, threatening oak trees. Here, we analyze and compare the proteomes of inner bark tissue sampled from oak stems of trees symptomatic with AOD and non-symptomatic trees.
Project description:Wood maturation produces two distinct wood tissues: juvenile wood (JW) and mature wood (LW), which are the major cause of wood qaulity variation within a tree. We investigate transcriptome reorganization during wood maturation process in radiata pine using a newly developed 18k cDNA microarrays.
Project description:The transcriptome of Phanerochaete chrysosporium control mycelium was compared to the transcriptome of mycelium grown on oak acetonic extractives containing medium. The array probes were designed from gene models taken from the Joint Genome Institute (JGI, Department of Energy) Phanerochaete chrysosporium genome sequence version 1. The aim of this study was to determine gene expression changes in Phanerochaete chrysosporium grown on oak extract with a special focus on detoxification systems.