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Abstract: The impact of long-lived radionuclides on human health depends on their behaviour in near-surface soils and sediments and the LORISE project aims to define the key controlling physical, chemical and biological processes at a number of ‘natural laboratories’ around the UK. Within this PhD project, the role of natural organic matter (NOM) is of especial importance because NOM can potentially facilitate the transport or attenuation of radiologically significant elements such as U and radiocarbon (14C). Peaty soils in the vicinity of natural uranium mineralisations are often highly enriched in U with concentrations of up to 3000 mg kg-1, 4000 mg kg-1 and 2500 mg kg-1 having been found in the US (Owen and Otten, 1995), Switzerland (Regenspurg et al., 2010), and the UK (Xu, 2013), respectively. The NOM within these soils has been implicated in U retention but the controlling processes and the nature of interactions are poorly characterised. The Needle’s Eye natural mineralisation, SW Scotland, provides a rare opportunity within the UK to investigate long-term U-NOM interactions. Similarly, the well characterised inputs of radiocarbon into the Irish Sea from the Sellafield nuclear reprocessing facility since the mid-1960s present an opportunity to investigate the transfer of anthropogenic 14C between environmental pools and trace its incorporation into coastal sediments. While the enrichment of sediment organic matter with anthropogenic 14C has been identified, (MacKenzie et al., 2004), the chemical and physical characteristics of NOM enriched with 14C have not been investigated. Currently, there is not a good understanding of which NOM components govern U binding or incorporate 14C, and therefore the implications of the influence of NOM on radionuclide mobilisation or immobilisation are hard to assess. In this study, the characteristics of organic matter from the Needle’s Eye natural analogue site have been examined and the relationship with the geochemical properties of the site and U binding have been investigated. Further to this, NOM extracted from the Needle’s Eye peat bog and from sediments of the Solway coast at the Southwick Merse has been fractionated and characterised using a range of spectroscopic techniques to identify the components of NOM which are responsible for binding U and those which incorporate anthropogenic 14C.

Open Access

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Abstract: Natural variation separates Epstein-Barr virus (EBV) into type 1 and type 2 strains. Type 2 EBV is less transforming in vitro due to sequence differences in the EBV transcription factor EBNA2. This correlates with reduced activation of the EBV oncogene LMP1 and some cell genes. Transcriptional activation by type 1 EBNA2 can be suppressed through the binding of two PXLXP motifs in its transactivation domain (TAD) to the dimeric coiled-coil MYND domain (CC-MYND) of the BS69 repressor protein (ZMYND11). We identified a third conserved PXLXP motif in type 2 EBNA2. We found that type 2 EBNA2 peptides containing this motif bound BS69CC-MYND efficiently and that the type 2 EBNA2TAD bound an additional BS69CC-MYND molecule. Full-length type 2 EBNA2 also bound BS69 more efficiently in pull-down assays. Molecular weight analysis and low-resolution structures obtained using small-angle X-ray scattering showed that three BS69CC-MYND dimers bound two molecules of type 2 EBNA2TAD, in line with the dimeric state of full-length EBNA2 in vivo. Importantly, mutation of the third BS69 binding motif in type 2 EBNA2 improved B-cell growth maintenance and the transcriptional activation of the LMP1 and CXCR7 genes. Our data indicate that increased association with BS69 restricts the function of type 2 EBNA2 as a transcriptional activator and driver of B cell growth and may contribute to reduced B-cell transformation by type 2 EBV.

Open Access

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Abstract: We present a new cell membrane modification methodology where the inherent heart tissue homing properties of the infectious bacteria Streptococcus gordonii are transferred to human stem cells. This is achieved via the rational design of a chimeric protein–polymer surfactant cell membrane binding construct, comprising the cardiac fibronectin (Fn) binding domain of the bacterial adhesin protein CshA fused to a supercharged protein. Significantly, the protein–polymer surfactant hybrid spontaneously inserts into the plasma membrane of stem cells without cytotoxicity, instilling the cells with a high affinity for immobilized fibronectin. Moreover, we show that this cell membrane reengineering approach significantly improves retention and homing of stem cells delivered either intracardially or intravenously to the myocardium in a mouse model.

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Abstract: By screening an epigenetic compound library, we identified that UNC0638, a highly potent inhibitor of the histone methyltransferases G9a and GLP, was a weak inhibitor of SPIN1 (Spindlin 1), a methyllysine reader protein. Our optimization of this weak hit resulted in the discovery of a potent, selective and cell-active SPIN1 inhibitor, compound 3 (MS31). Compound 3 potently inhibited binding of trimethyllysine-containing peptides to SPIN1, displayed high binding affinity, was highly selective for SPIN1 over other epigenetic readers and writers, directly engaged SPIN1 in cells, and was not toxic to non-tumorigenic cells. The crystal structure of the SPIN1–compound 3 complex indicated that it selectively binds Tudor domain II of SPIN1. We also designed a structurally similar but inactive compound 4 (MS31N) as a negative control. Our results have demonstrated for the first time that potent, selective and cell-active fragment-like inhibitors can be generated by targeting a single Tudor domain.

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Abstract: Pancreatic cancer is a leading cause of cancer-related death. A series of 2-amino-2, 3-dihydro-1H-indene-5-carboxamide derivatives were designed and synthesized as novel selective DDR1 inhibitors to exhibit promising in vitro and in vivo anti-pancreatic cancer activity. One of the representative compounds, 7f, binds with DDR1 with a Kd value of 5.9 nM and suppresses the kinase activity with an IC50 value of 14.9 nM, but is significantly less potent for majority of a panel of 403 wild-type kinases. The compound potently inhibited collagen-induced epithelial-mesenchymal transition (EMT) and dose-dependently suppressed colony formation of pancreatic cancer cells. Furthermore, 7f also demonstrated reasonable pharmacokinetic profiles and displayed promising in vivo therapeutic efficacy in an orthotopic mouse model of pancreatic cancer. Compound 7f may serve as a new lead compound for future drug discovery.