36 research outputs found
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The earliest Europeans – a year in the life: seasonal survival strategies in the Lower Palaeolithic
The Earliest Europeans explores a fundamental question: how did Europe’s first hominin occupants cope with the year-round practical challenges of life. To do so, the book adopts a ‘year in the life’ perspective that draws on the increasingly rich and robust archaeological and Quaternary Science records for the European Lower Palaeolithic, combined with insights from modern ethnography and zoological studies. By exploring potential survival strategies and behaviours, Hosfield offers new insights into the character of Europe’s earliest occupations across more than 1 million years, and ultimately asks: what sorts of ‘humans’ were these hominins?
The innovative season-by-season structure of the book explores cyclical fluctuations in resources and weather conditions. From the depths of cold winters to the bountiful foods of late summer, it considers the implications of these variations for hominin behaviours. Hosfield draws on a range of supporting examples and evidence from Lower Palaeolithic sites across Europe, spanning technology, palaeoenvironmental reconstructions, hominin life history, and plant and animal food resources. In doing so, The Earliest Europeans highlights both the current and future potential of Europe’s earliest archaeological record
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Modes of transmission and material culture patterns in craft skills
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The unsung heroes
This paper explores the roles played by local collectors, often little-known or rarely
remembered, in the compilation of Britain’s Earlier (Lower and early Middle) Palaeolithic
record, with reference to the work of C.E. (Charles) Bean at the Lower Palaeolithic site of
Broom, and the activities of George Smith and Llewellyn and Mabel Treacher in the Middle
Thames Valley. Their collecting practices, publication records, and archaeological
knowledge and insights are reviewed, and their impacts assessed with reference to the
activities of other contemporary collectors, and the regional archaeological records of the
south-west and the Middle Thames. Their archives demonstrate that while the key sites and
artefact assemblages sampled by Bean, Smith and the Treachers would not otherwise have
been unknown, their work left important legacies in terms of rich artefact assemblages, site
archives (Bean), and the long-term monitoring of key sites and fluvial terraces
The Earliest Europeans
The Earliest Europeans explores the early origins of man in Europe through the perspective of ‘a year in the life’: how hominins in the Lower Palaeolithic coped with the year-round practical challenges of mid-latitude Europe with its distinctive temperatures, seasonality patterns, and available resources.
Current research has provided increasingly robust archaeological and Quaternary Science records, but there are ongoing uncertainties as to both the earliest Europeans’ specific survival strategies and behaviours, and the character of their dispersals into Europe. In short, how sustained and ‘successful’ were the individual phases of European occupation by Lower Palaeolithic hominins and what sorts of ‘human’ where they
Earliest Europeans:Integrating perspectives from archaeology, palaeoanthropology and palaeoclimatology
Dna2 is a structure-specific nuclease, with affinity for 5'-flap intermediates
Dna2 is a nuclease/helicase with proposed roles in DNA replication, double-strand break repair and telomere maintenance. For each role Dna2 is proposed to process DNA substrates with a 5'-flap. To date, however, Dna2 has not revealed a preference for binding or cleavage of flaps over single-stranded DNA. Using DNA binding competition assays we found that Dna2 has substrate structure specificity. The nuclease displayed a strong preference for binding substrates with a 5'-flap or some variations of flap structure. Further analysis revealed that Dna2 recognized and bound both the single-stranded flap and portions of the duplex region immediately downstream of the flap. A model is proposed in which Dna2 first binds to a flap base, and then the flap threads through the protein with periodic cleavage, to a terminal flap length of ~5 nt. This resembles the mechanism of flap endonuclease 1, consistent with cooperation of these two proteins in flap processing
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Terrestrial implications for the maritime geoarchaeological resource: A view from the Lower Palaeolithic
Stone tools and faunal remains have been recovered from the English Channel and the North Sea through trawling, dredging for aggregates, channel clearance, and coring. These finds highlight the potential for a maritime Lower Palaeolithic archaeological resource. It is proposed here that any Lower Palaeolithic artefacts, faunal remains, and sediments deposited in the maritime zone during dry, low-stand phases were once (and may still be) contextually similar to their counterparts in the terrestrial Lower Palaeolithic records of north-western Europe. Given these similarities, can interpretive models and analytical frameworks developed for terrestrial archaeology be profitably applied to an assessment of the potential value of any maritime resource? The terrestrial geoarchaeological resource for the Lower Palaeolithic is dominated by artefacts and ecofacts that have been fluvially reworked. The spatio-temporal resolution of these data varies from entire river valleys and marine isotope stages to river channel gravel bar surfaces and decadal timescales, thus supporting a variety of questions and approaches. However, the structure of the terrestrial resource also highlights two fundamental limitations in current maritime knowledge that can restrict the application of terrestrial approaches to any potential maritime resource: (i) how have the repetitive transgressions and regressions of the Middle and Late Pleistocene modified the terrace landforms and sediments associated with the river systems of the English Channel and southern North Sea basins?; and (ii) do the surviving submerged terrace landforms and fluvial sedimentary deposits support robust geochronological models, as is the case with the classical terrestrial terrace sequences? This paper highlights potential approaches to these questions, and concludes that the fluvial palaeogeography, Pleistocene fossils, and potential Lower Palaeolithic artefacts of the maritime geoarchaeological resource can be profitably investigated in future as derived, low-resolution data sets, facilitating questions of colonisation, occupation, demography, and material culture
Dimerisation induced formation of the active site and the identification of three metal sites in EAL-phosphodiesterases
The bacterial second messenger cyclic di-3′,5′-guanosine monophosphate (c-di-GMP) is a key regulator of bacterial motility and virulence. As high levels of c-di-GMP are associated with the biofilm lifestyle, c-di-GMP hydrolysing phosphodiesterases (PDEs) have been identified as key targets to aid development of novel strategies to treat chronic infection by exploiting biofilm dispersal. We have studied the EAL signature motif-containing phosphodiesterase domains from the Pseudomonas aeruginosa proteins PA3825 (PA3825EAL) and PA1727 (MucREAL). Different dimerisation interfaces allow us to identify interface independent principles of enzyme regulation. Unlike previously characterised two-metal binding EAL-phosphodiesterases, PA3825EAL in complex with pGpG provides a model for a third metal site. The third metal is positioned to stabilise the negative charge of the 5′-phosphate, and thus three metals could be required for catalysis in analogy to other nucleases. This newly uncovered variation in metal coordination may provide a further level of bacterial PDE regulation
Use of green fluorescent protein for the analysis of protein-protein and protein-DNA interactions
Restriction modification (RM) systems play a crucial role in preventing the
entry of foreign DNA into the bacterial cell. The best studied Type I RM system is
EcoKI from Escherichia coli K12. Both bacteriophage and conjugative plasmids
have developed a variety of strategies to circumvent the host RM system. One such
strategy involves the production of antirestriction proteins that mimic a short
segment of DNA and efficiently inhibit the RM system. The main aim of this project
was to analyse the interaction of EcoKI and its cognate methylase (MTase) with the
T7 antirestriction protein, known as overcome classical restriction (Ocr), and various
ArdA antirestriction proteins. Currently, there is a paucity of structural data on the
complex formed between the Type I system and the antirestriction proteins. The aim
of this work was twofold; (i) compare the interaction of MTase with DNA and Ocr
and (ii) quantify the strength of interaction between MTase and various ArdA
proteins.
The MTase was fused to the Green Fluorescent Protein (GFP) to facilitate
determination of the orientation of interaction with DNA and Ocr. Time resolved
fluorescence measurements were carried out using the GFP-MTase fusion to
determine the fluorescence lifetime and anisotropy decay. These experiments were
conducted using a time resolved fluorescence instrument fabricated in-house. The
values determined in these experiments were then used to perform fluorescence
resonance energy transfer (FRET) measurements with fluorescently labelled DNA or
Ocr. These measurements gave information concerning the relative orientation of the
MTase with either DNA or Ocr.
The GFP-MTase fusion was also used to quantify the strength of interaction
with various ArdA proteins. Previous attempts to determine the strength of
interaction between MTase and ArdA proteins by employing conventional
techniques have been unsuccessful. Therefore, a novel method was developed that
exploits the interaction of MTase with a cation exchange medium, which can
subsequently be displaced upon binding to ArdA. This method facilitated the
determination, for the first time, of a set of binding affinities for the MTase and
ArdA interaction
AI is a viable alternative to high throughput screening: a 318-target study
: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery