73 research outputs found
Preparation, Characterization, Electrochemistry, and Infrared Spectroelectrochemistry of Ruthenium Nitrosyl Porphyrins Containing η1-O Bonded Axial Carboxylates
The synthesis, characterization and redox behavior of eight low-spin nitrosyl carboxylate compounds (por)Ru(NO)(η1-OC(=O)R) (por = T(p-OMe)PP: R = Me (1), i-Pr (2), t-Bu (3), p-C6H4NO2 (4), Fc (5), CF3 (8); por = TTP: R = Fc (6)) and (T(p-OMe)PP)Ru(NO)(OC6HF4) (7) are reported. The compounds are moderately stable in air as solids. Their IR (KBr) spectral data show ʋNO\u27s in the 1839-1861 range cm-1. The X-ray crystal structures of compounds 1, 2, 5-7, and 8 have been determined, and reveal linear RuNO linkages for these formally {RuNO}6 complexes. The redox behavior of the compounds at a Pt working electrode were studied in CH2Cl2 with NBu4PF6 as supporting electrolyte. The compounds display reversible first oxidations. IR spectroelectrochemistry of compounds 1-4, 7 and 8 revealed porphyrin centered oxidations, whereas the ferrocenylcarboxylate compounds revealed first oxidations at the ferrocenyl moiety followed by second oxidations at the porphyrin macrocycles. Reductions of these compounds are accompanied by loss of the axial ligands
Transcription control by the ENL YEATS domain in acute leukaemia
Recurrent chromosomal translocations producing a chimaeric MLL oncogene give rise to a highly aggressive acute leukaemia associated with poor clinical outcome. The preferential involvement of chromatin-associated factors as MLL fusion partners belies a dependency on transcription control. Despite recent progress made in targeting chromatin regulators in cancer, available therapies for this well-characterized disease remain inadequate, prompting the need to identify new targets for therapeutic intervention. Here, using unbiased CRISPR-Cas9 technology to perform a genome-scale loss-of-function screen in an MLL-AF4-positive acute leukaemia cell line, we identify ENL as an unrecognized gene that is specifically required for proliferation in vitro and in vivo. To explain the mechanistic role of ENL in leukaemia pathogenesis and dynamic transcription control, a chemical genetic strategy was developed to achieve targeted protein degradation. Acute loss of ENL suppressed the initiation and elongation of RNA polymerase II at active genes genome-wide, with pronounced effects at genes featuring a disproportionate ENL load. Notably, an intact YEATS chromatin-reader domain was essential for ENL-dependent leukaemic growth. Overall, these findings identify a dependency factor in acute leukaemia and suggest a mechanistic rationale for disrupting the YEATS domain in disease.K. LubinE. Wood
Structural and Atropisomeric Factors Governing the Selectivity of Pyrimido-benzodiazipinones as Inhibitors of Kinases and Bromodomains
This is the author accepted manuscript. The final version is available from American Chemical Society via the DOI in this recordBromodomains have been pursued intensively over the past several years as emerging targets for the devel-opment of anti-cancer and anti-inflammatory agents. It has recently been shown that some kinase inhibitors are able to potently inhibit the bromodomains of BRD4. The clinical activities of PLK inhibitor BI-2536 and JAK2-FLT3 inhibitor TG101348 have been attributed to this unexpected poly-pharmacology, indicating that dual-kinase/bromodomain activity may be advantageous in a therapeutic context. However, for target validation and biological investigation, a more selec-tive target profile is desired. Here we report that benzo[e]pyrimido-[5,4-b]diazepine-6(11H)-ones, versatile ATP-site di-rected kinase pharmacophores utilized in the development of inhibitors of multiple kinases including a number of previ-ously reported kinase chemical probes, are also capable of exhibiting potent BRD4-dependent pharmacology. Using a dual kinase-bromodomain inhibitor of the kinase domains of ERK5 and LRRK2, and the bromodomain of BRD4 as a case study, we define the structure-activity relationships required to achieve dual kinase/BRD4 activity as well as how to di-rect selectivity towards inhibition of either ERK5 or BRD4. This effort resulted in identification of one of the first report-ed kinase-selective chemical probes for ERK5 (JWG-071), a BET selective inhibitor with 1 μM BRD4 IC50 (JWG-115), and additional inhibitors with rationally designed polypharmacology (JWG-047, JWG-069). Co-crystallography of seven representative inhibitors with the first bromodomain of BRD4 demonstrate that distinct atropisomeric conformers rec-ognize the kinase ATP-site and the BRD4 acetyl lysine binding site, conformational preferences supported by rigid dock-ing studies.This work was supported by NIH (Grant No. U54HL127365, to N.S.G. and J.W.; No. NIH P50 GM107618, to X.X. and S.C.B.; Nos. NIH U54 HD093540 and P01 CA066996, to J.Q.), the Medical Research Council (No. MC_UU_12016/2, to D.R.A.), the Spanish Ministerio de Economia y Competitividad (MINECO) (Grant No. SAF2015-60268R, to J.M.L.), and Fondo Europeo de Desarrollo Regional (FEDER) funds (to J.M.L.). D.L.B. was supported as a Merck Fellow of Damon Runyon Cancer Research Foundation (No. DRG-2196-14)
RNA degradome—its biogenesis and functions
RNA degradation is among the most fundamental processes that occur in living cells. The continuous decay of RNA molecules is associated not only with nucleotide turnover, but also with transcript maturation and quality control. The efficiency of RNA decay is ensured by a broad spectrum of both specific and non-specific ribonucleases. Some of these ribonucleases participate mainly in processing primary transcripts and in RNA quality control. Others preferentially digest mature, functional RNAs to yield a variety of molecules that together constitute the RNA degradome. Recently, it has become increasingly clear that the composition of the cellular RNA degradome can be modulated by numerous endogenous and exogenous factors (e.g. by stress). In addition, instead of being hydrolyzed to single nucleotides, some intermediates of RNA degradation can accumulate and function as signalling molecules or participate in mechanisms that control gene expression. Thus, RNA degradation appears to be not only a process that contributes to the maintenance of cellular homeostasis but also an underestimated source of regulatory molecules
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Perspective: Food environment research priorities for Africa—Lessons from the Africa Food Environment Research Network
Over the last 2 decades, many African countries have undergone dietary and nutrition transitions fuelled by globalization, rapid urbanization, and development. These changes have altered African food environments and, subsequently, dietary behaviors, including food acquisition and consumption. Dietary patterns associated with the nutrition transition have contributed to Africa's complex burden of malnutrition—obesity and other diet-related noncommunicable diseases (DR-NCDs)—along with persistent food insecurity and undernutrition. Available evidence links unhealthy or obesogenic food environments (including those that market and offer energy-dense, nutrient-poor foods and beverages) with suboptimal diets and associated adverse health outcomes. Elsewhere, governments have responded with policies to improve food environments. However, in Africa, the necessary research and policy action have received insufficient attention. Contextual evidence to motivate, enable, and create supportive food environments in Africa for better population health is urgently needed. In November 2020, the Measurement, Evaluation, Accountability, and Leadership Support for Noncommunicable Diseases Prevention Project (MEALS4NCDs) convened the first Africa Food Environment Research Network Meeting (FERN2020). This 3-d virtual meeting brought researchers from around the world to deliberate on future directions and research priorities related to improving food environments and nutrition across the African continent. The stakeholders shared experiences, best practices, challenges, and opportunities for improving the healthfulness of food environments and related policies in low- and middle-income countries. In this article, we summarize the proceedings and research priorities identified in the meeting to advance the food environment research agenda in Africa, and thus contribute to the promotion of healthier food environments to prevent DR-NCDs, and other forms of malnutrition
'Vernacular Voices: Black British Poetry'
ABSTRACT
Black British poetry is the province of experimenting with voice and recording rhythms beyond the iambic pentameter. Not only in performance poetry and through the spoken word, but also on the page, black British poetry constitutes and preserves a sound archive of distinct linguistic varieties. In Slave Song (1984) and Coolie Odyssey (1988), David Dabydeen employs a form of Guyanese Creole in order to linguistically render and thus commemorate the experience of slaves and indentured labourers, respectively, with the earlier collection providing annotated translations into Standard English. James Berry, Louise Bennett, and Valerie Bloom adapt Jamaican Patois to celebrate Jamaican folk culture and at times to represent and record experiences and linguistic interactions in the postcolonial metropolis. Grace Nichols and John Agard use modified forms of Guyanese Creole, with Nichols frequently constructing gendered voices whilst Agard often celebrates linguistic playfulness. The borders between linguistic varieties are by no means absolute or static, as the emergence and marked growth of ‘London Jamaican’ (Mark Sebba) indicates. Asian British writer Daljit Nagra takes liberties with English for different reasons. Rather than having recourse to established Creole languages, and blending them with Standard English, his heteroglot poems frequently emulate ‘Punglish’, the English of migrants whose first language is Punjabi. Whilst it is the language prestige of London Jamaican that has been significantly enhanced since the 1990s, a fact not only confirmed by linguistic research but also by its transethnic uses both in the streets and on the page, Nagra’s substantial success and the mainstream attention he receives also indicate the clout of vernacular voices in poetry. They have the potential to connect with oral traditions and cultural memories, to record linguistic varieties, and to endow ‘street cred’ to authors and texts. In this chapter, these double-voiced poetic languages are also read as signs of resistance against residual monologic ideologies of Englishness.
© Book proposal (02/2016): The Cambridge History of Black and Asian British Writing p. 27 of 4
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Forging connections: anthologies, arts collectives, and the politics of inclusion
The changing social and political landscape of twentieth-century Britain catalysed a remarkable rise in collaborative activity by artists and activists of black and Asian heritage. Creative communities began to gather in both local and regional contexts, with the aim of sharing resources and securing an audience. This chapter records some of these many activities, tracing the groups’ genesis, manifest objectives, and key contributions. It argues that anthologising should be understood as a specifically motivated activity. Literary anthologies of poetry and fiction served to showcase the diversity of contemporary writing, while also suggesting its coherence. Drawing on the concept of “strategic essentialism” elucidated by Gayatri Chakravorty Spivak, I show that the anthology acts to ensure the visibility of a group, bannered as a unified and singly-titled selection of texts, while also insisting on the differences within: the heterogeneous multiplicity of black and Asian British experiences and creative practices
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century
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