ORCID Profile
0000-0001-6406-0393
Current Organisations
Yarmouk University
,
University of Oxford
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Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 10-2015
Publisher: eLife Sciences Publications, Ltd
Date: 14-06-2022
DOI: 10.7554/ELIFE.77195
Abstract: During severe infections, Staphylococcus aureus moves from its colonising sites to blood and tissues and is exposed to new selective pressures, thus, potentially driving adaptive evolution. Previous studies have shown the key role of the agr locus in S. aureus pathoadaptation however, a more comprehensive characterisation of genetic signatures of bacterial adaptation may enable prediction of clinical outcomes and reveal new targets for treatment and prevention of these infections. Here, we measured adaptation using within-host evolution analysis of 2590 S . aureus genomes from 396 independent episodes of infection. By capturing a comprehensive repertoire of single nucleotide and structural genome variations, we found evidence of a distinctive evolutionary pattern within the infecting populations compared to colonising bacteria. These invasive strains had up to 20-fold enrichments for genome degradation signatures and displayed significantly convergent mutations in a distinctive set of genes, linked to antibiotic response and pathogenesis. In addition to agr -mediated adaptation, we identified non-canonical, genome-wide significant loci including sucA-sucB and stp1 . The prevalence of adaptive changes increased with infection extent, emphasising the clinical significance of these signatures. These findings provide a high-resolution picture of the molecular changes when S. aureus transitions from colonisation to severe infection and may inform correlation of infection outcomes with adaptation signatures.
Publisher: Springer Science and Business Media LLC
Date: 26-02-2022
Publisher: Zenodo
Date: 2016
Publisher: Cold Spring Harbor Laboratory
Date: 12-02-2022
DOI: 10.1101/2022.02.11.480068
Abstract: During severe infections, Staphylococcus aureus moves from its colonising sites to blood and tissues, and is exposed to new selective pressures, thus potentially driving adaptive evolution. Previous studies have shown the key role of the agr locus in S. aureus pathoadaptation, however a more comprehensive characterisation of genetic signatures of bacterial adaptation may enable prediction of clinical outcomes and reveal new targets for treatment and prevention of these infections. Here, we measured adaptation using within-host evolution analysis of 2,590 S. aureus genomes from 396 independent episodes of infection. By capturing a comprehensive repertoire of single-nucleotide and structural genome variations, we found evidence of a distinctive evolutionary pattern within the infecting populations compared to colonising bacteria. These invasive strains had up to 20-fold enrichments for genome degradation signatures and displayed significantly convergent mutations in a distinctive set of genes, linked to antibiotic response and pathogenesis. In addition to agr -mediated adaptation we identified non-canonical, genome-wide significant loci including sucA - sucB and stp1 . The prevalence of adaptive changes increased with infection extent, emphasising the clinical significance of these signatures. These findings provide a high-resolution picture of the molecular changes when S. aureus transitions from colonisation to severe infection and may inform correlation of infection outcomes with adaptation signatures.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Springer Science and Business Media LLC
Date: 08-03-2019
Publisher: eLife Sciences Publications, Ltd
Date: 17-05-2022
Publisher: Cambridge University Press (CUP)
Date: 06-08-2020
DOI: 10.1017/RDC.2019.90
Abstract: In this study, we investigate quartz-based luminescence optical dating of Iron Age deposits at the archaeological site of Tell Damiyah in the Jordan valley. Ten s les, taken from different occupation layers from two different excavation areas, proved to have good luminescence characteristics (fast-component dominated, dose recovery ratio 1.032 ± 0.010, n=24). The optical ages are completely consistent with both available 14 C ages and ages based on stylistic elements it appears that this material was fully reset at deposition, although it is recognised that the agreement with age control is somewhat dependent on the assumed field water content of the s les. Further comparison with different OSL signals from feldspar, or investigations based on dose distributions from in idual grains would be desirable to independently confirm the resetting of this material. It is concluded that the sediments of Tell Damiyah are very suitable for luminescence dating. Despite the relatively large associated age uncertainties of between 5 and 10%, OSL at tell sites has the potential to provide ages for material very difficult to date by conventional methods, and to identify reworked mixtures of older artifacts in a younger depositional setting.
Publisher: Walter de Gruyter GmbH
Date: 2017
Abstract: Recent developments in the use of more stable feldspar signals in the luminescence dating of sediments offer the possibility of obtaining accurate feldspar luminescence ages for ceramic artefacts this is especially interesting in locations which do not provide suitable quartz extracts. Here we examine the application of the stable infrared stimulated luminescence signal measured at elevated temperature (in this case 290°C pIRIR 290 ) after stimulation at about room temperature to Levantine pottery s les. A total of 52 potsherds were collected from three superimposed iron-age units at Pella (Jordan) based on 14 C dating, typology and seriation these units were deposited between 700 and 900 BCE. Sand-sized quartz extracts were unsuitable, and there was insufficient sand-sized feldspar, and so polymineral fine grains were chosen for dating. Various tests for reliability were undertaken (dose recovery, dependence of D e on first stimulation temperature etc .). The pIRIR signals are weak, and 14 potsherds were rejected on this basis. Of the remainder, 3 were confidently identified as outliers. Based on those sherds for which IR signals were sufficiently intense, we use the ratio of the IR 50 to pIRIR 290 signals to argue that these outliers do not arise from incomplete resetting during manufacture. The ages from each layer are considerably over dispersed (typically by ∼25%) but average ages for each unit are consistent with each other and with the expected age range. The average OSL age for the site is 2840 ± 220 years (n = 35), with the overall uncertainty dominated by systematic uncertainties this average is consistent with the range of 14 C ages from 970–1270 BCE reported from across the destruction horizon. We conclude that the pIRIR 290 signal is delivering accurate ages, but that the variability in age from shard to shard is much greater than would be expected from known sources of uncertainty. This demonstrates the need for site ages to be based on multiple s les in idual shard ages are unlikely to be sufficiently accurate.
Publisher: Springer Science and Business Media LLC
Date: 11-06-2018
Publisher: Wiley
Date: 19-04-2023
DOI: 10.1111/ARCM.12871
Abstract: This study uses quartz‐based optically stimulated luminescence dating to determine when a massive fortification wall (W11186) was constructed in the archaeological site of Tall Zarʿa in the Jordan Valley. A total of 11 s les of sediments were taken from a trench on the north side of the wall ( extramuros ). The extracted quartz grains had good luminescence characteristics and were identified as well bleached by comparison with feldspar infrared‐stimulated luminescence (IRSL) ages. The optical ages showed that the deposition against the wall occurred in two different periods. The first was around 3.20 ± 0.07 ka ago (Iron Age), and the second was around 2.28 ± 0.08 ka (Hellenistic period). Human activity was evident because of the intermixing of cultural material with the presumed naturally deposited units.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Sahar al Khasawneh.