9 research outputs found

    Anglo-Saxon diet in the Conversion period: A comparative isotopic study using carbon and nitrogen

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    © 2018 Elsevier Ltd Seventh-century Anglo-Saxon England is characterised by great social and religious change. The arrival of missionaries from Rome in 597 CE initiated the gradual process of conversion to Christianity. There is growing evidence for increasing hierarchy and social stratification in the archaeological record at this time, including prominent kingly burials. This paper investigates whether diet was influenced by social stratification and to a lesser extent religion in two seventh-century cemetery populations: Melbourn, Cambridgeshire, and Polhill, Kent. Analysis of carbon and nitrogen stable isotopes from 116 human individuals was undertaken. Factors considered included age, sex, wealth and other notable grave features. Results showed that the diets of both populations were largely unaffected by these wider social processes, with negligible differences between social groups. The results were placed in the context of wider Anglo-Saxon dietary studies and highlight that Anglo-Saxon populations consistently display overwhelmingly similar ranges of carbon and nitrogen isotopes

    A Peptidoglycan Fragment Triggers β-lactam Resistance in Bacillus licheniformis

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    To resist to β-lactam antibiotics Eubacteria either constitutively synthesize a β-lactamase or a low affinity penicillin-binding protein target, or induce its synthesis in response to the presence of antibiotic outside the cell. In Bacillus licheniformis and Staphylococcus aureus, a membrane-bound penicillin receptor (BlaR/MecR) detects the presence of β-lactam and launches a cytoplasmic signal leading to the inactivation of BlaI/MecI repressor, and the synthesis of a β-lactamase or a low affinity target. We identified a dipeptide, resulting from the peptidoglycan turnover and present in bacterial cytoplasm, which is able to directly bind to the BlaI/MecI repressor and to destabilize the BlaI/MecI-DNA complex. We propose a general model, in which the acylation of BlaR/MecR receptor and the cellular stress induced by the antibiotic, are both necessary to generate a cell wall-derived coactivator responsible for the expression of an inducible β-lactam-resistance factor. The new model proposed confirms and emphasizes the role of peptidoglycan degradation fragments in bacterial cell regulation
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