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result(s) for
"Rayner, T S M"
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Far-infrared observations of a massive cluster forming in the Monoceros R2 filament hub
by
Anderson, L D
,
André, P
,
Peretto, N
in
Astronomical instruments
,
Deposition
,
Energy measurement
2017
We present far-infrared observations of Monoceros R2 (a giant molecular cloud at approximately 830 pc distance, containing several sites of active star formation), as observed at 70 {\\mu}m, 160 {\\mu}m, 250 {\\mu}m, 350 {\\mu}m, and 500 {\\mu}m by the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) instruments on the Herschel Space Observatory as part of the Herschel imaging survey of OB young stellar objects (HOBYS) Key programme. The Herschel data are complemented by SCUBA-2 data in the submillimetre range, and WISE and Spitzer data in the mid-infrared. In addition, C18O data from the IRAM 30-m Telescope are presented, and used for kinematic information. Sources were extracted from the maps with getsources, and from the fluxes measured, spectral energy distributions were constructed, allowing measurements of source mass and dust temperature. Of 177 Herschel sources robustly detected in the region (a detection with high signal-to-noise and low axis ratio at multiple wavelengths), including protostars and starless cores, 29 are found in a filamentary hub at the centre of the region (a little over 1% of the observed area). These objects are on average smaller, more massive, and more luminous than those in the surrounding regions (which together suggest that they are at a later stage of evolution), a result that cannot be explained entirely by selection effects. These results suggest a picture in which the hub may have begun star formation at a point significantly earlier than the outer regions, possibly forming as a result of feedback from earlier star formation. Furthermore, the hub may be sustaining its star formation by accreting material from the surrounding filaments.
Antagonism of miR-33 in mice promotes reverse cholesterol transport and regression of atherosclerosis
by
Esau, Christine C.
,
Temel, Ryan E.
,
van Gils, Janine M.
in
Animals
,
Atherosclerosis
,
Atherosclerosis - genetics
2011
Plasma HDL levels have a protective role in atherosclerosis, yet clinical therapies to raise HDL levels have remained elusive. Recent advances in the understanding of lipid metabolism have revealed that miR-33, an intronic microRNA located within the SREBF2 gene, suppresses expression of the cholesterol transporter ABC transporter A1 (ABCA1) and lowers HDL levels. Conversely, mechanisms that inhibit miR-33 increase ABCA1 and circulating HDL levels, suggesting that antagonism of miR-33 may be atheroprotective. As the regression of atherosclerosis is clinically desirable, we assessed the impact of miR-33 inhibition in mice deficient for the LDL receptor (Ldlr-/- mice), with established atherosclerotic plaques. Mice treated with anti-miR33 for 4 weeks showed an increase in circulating HDL levels and enhanced reverse cholesterol transport to the plasma, liver, and feces. Consistent with this, anti-miR33-treated mice showed reductions in plaque size and lipid content, increased markers of plaque stability, and decreased inflammatory gene expression. Notably, in addition to raising ABCA1 levels in the liver, anti-miR33 oligonucleotides directly targeted the plaque macrophages, in which they enhanced ABCA1 expression and cholesterol removal. These studies establish that raising HDL levels by anti-miR33 oligonucleotide treatment promotes reverse cholesterol transport and atherosclerosis regression and suggest that it may be a promising strategy to treat atherosclerotic vascular disease.
Journal Article
System-wide analysis of RNA and protein subcellular localization dynamics
2024
Although the subcellular dynamics of RNA and proteins are key determinants of cell homeostasis, their characterization is still challenging. Here we present an integrative framework to simultaneously interrogate the dynamics of the transcriptome and proteome at subcellular resolution by combining two methods: localization of RNA (LoRNA) and a streamlined density-based localization of proteins by isotope tagging (dLOPIT) to map RNA and protein to organelles (nucleus, endoplasmic reticulum and mitochondria) and membraneless compartments (cytosol, nucleolus and cytosolic granules). Interrogating all RNA subcellular locations at once enables system-wide quantification of the proportional distribution of RNA. We obtain a cell-wide overview of localization dynamics for 31,839 transcripts and 5,314 proteins during the unfolded protein response, revealing that endoplasmic reticulum-localized transcripts are more efficiently recruited to cytosolic granules than cytosolic RNAs, and that the translation initiation factor eIF3d is key to sustaining cytoskeletal function. Overall, we provide the most comprehensive overview so far of RNA and protein subcellular localization dynamics.
An integrative framework to simultaneously interrogate the dynamics of the transcriptome and proteome at subcellular resolution that combines two methods, localization of RNA (LoRNA) and a streamlined density-based localization of proteins by isotope tagging (dLOPIT).
Journal Article
Warming and redistribution of nitrogen inputs drive an increase in terrestrial nitrous oxide emission factor
2022
Anthropogenic nitrogen inputs cause major negative environmental impacts, including emissions of the important greenhouse gas N₂O. Despite their importance, shifts in terrestrial N loss pathways driven by global change are highly uncertain. Here we present a coupled soil-atmosphere isotope model (IsoTONE) to quantify terrestrial N losses and N₂O emission factors from 1850-2020. We find that N inputs from atmospheric deposition caused 51% of anthropogenic N₂O emissions from soils in 2020. The mean effective global emission factor for N₂O was 4.3 ± 0.3% in 2020 (weighted by N inputs), much higher than the surface area-weighted mean (1.1 ± 0.1%). Climate change and spatial redistribution of fertilisation N inputs have driven an increase in global emission factor over the past century, which accounts for 18% of the anthropogenic soil flux in 2020. Predicted increases in fertilisation in emerging economies will accelerate N₂O-driven climate warming in coming decades, unless targeted mitigation measures are introduced.
Journal Article
Comprehensive identification of RNA–protein interactions in any organism using orthogonal organic phase separation (OOPS)
by
Pizzinga, Mariavittoria
,
Harvey, Robert F.
,
Marti-Solano, Maria
in
631/337/475
,
631/45/500
,
631/45/612
2019
Existing high-throughput methods to identify RNA-binding proteins (RBPs) are based on capture of polyadenylated RNAs and cannot recover proteins that interact with nonadenylated RNAs, including long noncoding RNA, pre-mRNAs and bacterial RNAs. We present orthogonal organic phase separation (OOPS), which does not require molecular tagging or capture of polyadenylated RNA, and apply it to recover cross-linked protein–RNA and free protein, or protein-bound RNA and free RNA, in an unbiased way. We validated OOPS in HEK293, U2OS and MCF10A human cell lines, and show that 96% of proteins recovered were bound to RNA. We show that all long RNAs can be cross-linked to proteins, and recovered 1,838 RBPs, including 926 putative novel RBPs. OOPS is approximately 100-fold more efficient than existing methods and can enable analyses of dynamic RNA–protein interactions. We also characterize dynamic changes in RNA–protein interactions in mammalian cells following nocodazole arrest, and present a bacterial RNA-interactome for
Escherichia coli
. OOPS is compatible with downstream proteomics and RNA sequencing, and can be applied in any organism.
RNA-binding proteins can be identified and quantified in any organism using a simple method that combines UV cross-linking and phase separation.
Journal Article
HIV epidemiology, prevention, treatment, and implementation strategies for public health
by
Mody, Aaloke
,
Sohn, Annette H
,
Tan, Rayner K J
in
Acquired immune deficiency syndrome
,
AIDS
,
COVID-19
2024
The global HIV response has made tremendous progress but is entering a new phase with additional challenges. Scientific innovations have led to multiple safe, effective, and durable options for treatment and prevention, and long-acting formulations for 2-monthly and 6-monthly dosing are becoming available with even longer dosing intervals possible on the horizon. The scientific agenda for HIV cure and remission strategies is moving forward but faces uncertain thresholds for success and acceptability. Nonetheless, innovations in prevention and treatment have often failed to reach large segments of the global population (eg, key and marginalised populations), and these major disparities in access and uptake at multiple levels have caused progress to fall short of their potential to affect public health. Moving forward, sharper epidemiologic tools based on longitudinal, person-centred data are needed to more accurately characterise remaining gaps and guide continued progress against the HIV epidemic. We should also increase prioritisation of strategies that address socio-behavioural challenges and can lead to effective and equitable implementation of existing interventions with high levels of quality that better match individual needs. We review HIV epidemiologic trends; advances in HIV prevention, treatment, and care delivery; and discuss emerging challenges for ending the HIV epidemic over the next decade that are relevant for general practitioners and others involved in HIV care.
Journal Article
Global variability in withholding and withdrawal of life-sustaining treatment in the intensive care unit: a systematic review
2015
Purpose
Prior studies identified high variability in prevalence of withdrawal of life-sustaining treatment in the ICU. Variability in end-of-life decision-making has been reported at many levels: between countries, ICUs, and individual intensivists. We performed a systematic review examining regional, national, inter-hospital, and inter-physician variability in withdrawal of life-sustaining treatment in the ICU.
Methods
Using a predefined search strategy, we queried three electronic databases for peer-reviewed articles addressing withdrawal of life-sustaining treatment in adult patients in the ICU. Data were analyzed for variability in prevalence of withdrawal of life-sustaining treatment. Withholding of life-sustaining treatment was also examined where information was provided. An assessment tool was developed to quantify the risk of bias in the included articles.
Results
We identified 1284 studies, with 56 included after review. Most studies had unclear or high risk of bias, primarily due to unclear case definitions or potential confounding. The mean prevalence of withdrawal of life-sustaining treatment for patients who died varied from 0 to 84.1 % between studies, with standard deviation of 23.7 %. Sensitivity analysis of general ICU patients yielded similar results. Withholding also varied between 5.3 and 67.3 % (mean 27.3, SD 18.5 %). Substantial variability was found between world regions, countries, individual ICUs within a country, and individual intensivists within one ICU.
Conclusions
We identified substantial variability in the withdrawal of life-sustaining treatment across world regions and countries. Similar variability existed between ICUs within countries and even between providers within the same ICU. Further study is necessary, and could lead to interventions to improve end-of-life care in the ICU.
Journal Article
Fundamentals of data assimilation applied to biogeochemistry
by
Rayner, Peter J.
,
Michalak, Anna M.
,
Chevallier, Frédéric
in
Bayesian analysis
,
Biogeochemistry
,
Continental interfaces, environment
2019
This article lays out the fundamentals of data assimilation as used in biogeochemistry. It demonstrates that all of the methods in widespread use within the field are special cases of the underlying Bayesian formalism. Methods differ in the assumptions they make and information they provide on the probability distributions used in Bayesian calculations. It thus provides a basis for comparison and choice among these methods. It also provides a standardised notation for the various quantities used in the field.
Journal Article
Revealing the Sequence and Resulting Cellular Morphology of Receptor-Ligand Interactions during Plasmodium falciparum Invasion of Erythrocytes
by
de Jong, Nienke W. M.
,
Rayner, Julian C.
,
Barlow, Paul N.
in
Animals
,
Antigens, Protozoan - metabolism
,
Basigin - metabolism
2015
During blood stage Plasmodium falciparum infection, merozoites invade uninfected erythrocytes via a complex, multistep process involving a series of distinct receptor-ligand binding events. Understanding each element in this process increases the potential to block the parasite's life cycle via drugs or vaccines. To investigate specific receptor-ligand interactions, they were systematically blocked using a combination of genetic deletion, enzymatic receptor cleavage and inhibition of binding via antibodies, peptides and small molecules, and the resulting temporal changes in invasion and morphological effects on erythrocytes were filmed using live cell imaging. Analysis of the videos have shown receptor-ligand interactions occur in the following sequence with the following cellular morphologies; 1) an early heparin-blockable interaction which weakly deforms the erythrocyte, 2) EBA and PfRh ligands which strongly deform the erythrocyte, a process dependant on the merozoite's actin-myosin motor, 3) a PfRh5-basigin binding step which results in a pore or opening between parasite and host through which it appears small molecules and possibly invasion components can flow and 4) an AMA1-RON2 interaction that mediates tight junction formation, which acts as an anchor point for internalization. In addition to enhancing general knowledge of apicomplexan biology, this work provides a rational basis to combine sequentially acting merozoite vaccine candidates in a single multi-receptor-blocking vaccine.
Journal Article
Exoproteome profiling of Trypanosoma cruzi during amastigogenesis early stages
by
Mandacaru, Samuel C.
,
de Lima, Consuelo M. R.
,
Santana, Jaime M.
in
Biochemistry
,
Biology and Life Sciences
,
Cell division
2019
Chagas disease is caused by the protozoan Trypanosoma cruzi, affecting around 8 million people worldwide. After host cell invasion, the infective trypomastigote form remains 2-4 hours inside acidic phagolysosomes to differentiate into replicative amastigote form. In vitro acidic-pH-induced axenic amastigogenesis was used here to study this step of the parasite life cycle. After three hours of trypomastigote incubation in amastigogenesis promoting acidic medium (pH 5.0) or control physiological pH (7.4) medium samples were subjected to three rounds of centrifugation followed by ultrafiltration of the supernatants. The resulting exoproteome samples were trypsin digested and analysed by nano flow liquid chromatography coupled to tandem mass spectrometry. Computational protein identification searches yielded 271 and 483 protein groups in the exoproteome at pH 7.4 and pH 5.0, respectively, with 180 common proteins between both conditions. The total amount and diversity of proteins released by parasites almost doubled upon acidic incubation compared to control. Overall, 76.5% of proteins were predicted to be secreted by classical or non-classical pathways and 35.1% of these proteins have predicted transmembrane domains. Classical secretory pathway analysis showed an increased number of mucins and mucin-associated surface proteins after acidic incubation. However, the number of released trans-sialidases and surface GP63 peptidases was higher at pH 7.4. Trans-sialidases and mucins are anchored to the membrane and exhibit an enzyme-substrate relationship. In general, mucins are glycoproteins with immunomodulatory functions in Chagas disease, present mainly in the epimastigote and trypomastigote surfaces and could be enzymatically cleaved and released in the phagolysosome during amastigogenesis. Moreover, evidence for flagella discard during amastigogenesis are addressed. This study provides the first comparative analysis of the exoproteome during amastigogenesis, and the presented data evidence the dynamism of its profile in response to acidic pH-induced differentiation.
Journal Article