ca American Diplomacy: Past, Present and Future By feedproxy.google.com Published On :: Mon, 01 Apr 2019 00:00:00 +0100 Full Article
ca Protection of the Wounded and Medical Care-Givers in Armed Conflict: Is the Law Up to the Job? By feedproxy.google.com Published On :: Thu, 16 May 2019 00:00:00 +0100 Full Article
ca Tectonic Politics: Navigating New Geopolitical Risks By feedproxy.google.com Published On :: Wed, 05 Jun 2019 00:00:00 +0100 Full Article
ca Africa’s Economic Outlook in a Challenging External Environment By feedproxy.google.com Published On :: Mon, 10 Jun 2019 00:00:00 +0100 Full Article
ca Conflict Economies in the Middle East and North Africa By feedproxy.google.com Published On :: Tue, 25 Jun 2019 00:00:00 +0100 Full Article
ca Artificial Intelligence and the Public: Prospects, Perceptions and Implications By feedproxy.google.com Published On :: Fri, 28 Jun 2019 00:00:00 +0100 Full Article
ca Undercurrents: Summer Special - Andrés Rozental on Mexican Politics By feedproxy.google.com Published On :: Thu, 01 Aug 2019 00:00:00 +0100 Full Article
ca Podcast: The Power of Viral Stories, with Professor Robert Shiller By feedproxy.google.com Published On :: Fri, 20 Sep 2019 00:00:00 +0100 Full Article
ca Jihad and Terrorism in Pakistan: The Case of Lashkar-e-Taiba By feedproxy.google.com Published On :: Fri, 27 Sep 2019 00:00:00 +0100 Full Article
ca Iraq’s Political Landscape (English version) By feedproxy.google.com Published On :: Wed, 02 Oct 2019 00:00:00 +0100 Full Article
ca Reflections on the State of Political Discourse By feedproxy.google.com Published On :: Wed, 16 Oct 2019 00:00:00 +0100 Full Article
ca A New Vision for American Foreign Policy By feedproxy.google.com Published On :: Mon, 21 Oct 2019 00:00:00 +0100 Full Article
ca Plaintiff in Chief: President Trump and the American Legal System By feedproxy.google.com Published On :: Wed, 30 Oct 2019 00:00:00 +0000 Full Article
ca Podcast: International Law, Security and Prosperity in the Asia-Pacific By feedproxy.google.com Published On :: Fri, 01 Nov 2019 00:00:00 +0000 Full Article
ca Brexit in a Historical Context: Pursuing a Global Vision at the Expense of Domestic Harmony? By feedproxy.google.com Published On :: Tue, 12 Nov 2019 00:00:00 +0000 Full Article
ca Understanding South Africa's Political Landscape By feedproxy.google.com Published On :: Thu, 14 Nov 2019 00:00:00 +0000 Full Article
ca Simulation: The Implications of Drone Warfare By feedproxy.google.com Published On :: Thu, 28 Nov 2019 00:00:00 +0000 Full Article
ca Undercurrents: Episode 41 - Personalized Political Advertising, and Climate Justice in Chile By feedproxy.google.com Published On :: Fri, 29 Nov 2019 00:00:00 +0000 Full Article
ca UK General Election 2019: Foreign Policy Implications By feedproxy.google.com Published On :: Wed, 11 Dec 2019 00:00:00 +0000 Full Article
ca Undercurrents: Episode 50 - The Coronavirus Communications Crisis, and Justice in Myanmar By feedproxy.google.com Published On :: Thu, 23 Apr 2020 00:00:00 +0100 Full Article
ca Correction: Diversity in the Protein N-Glycosylation Pathways Within the Campylobacter Genus. [Additions and Corrections] By feedproxy.google.com Published On :: 2020-05-01T00:05:26-07:00 Full Article
ca Phosphotyrosine-based Phosphoproteomics for Target Identification and Drug Response Prediction in AML Cell Lines [Research] By feedproxy.google.com Published On :: 2020-05-01T00:05:26-07:00 Acute myeloid leukemia (AML) is a clonal disorder arising from hematopoietic myeloid progenitors. Aberrantly activated tyrosine kinases (TK) are involved in leukemogenesis and are associated with poor treatment outcome. Kinase inhibitor (KI) treatment has shown promise in improving patient outcome in AML. However, inhibitor selection for patients is suboptimal. In a preclinical effort to address KI selection, we analyzed a panel of 16 AML cell lines using phosphotyrosine (pY) enrichment-based, label-free phosphoproteomics. The Integrative Inferred Kinase Activity (INKA) algorithm was used to identify hyperphosphorylated, active kinases as candidates for KI treatment, and efficacy of selected KIs was tested. Heterogeneous signaling was observed with between 241 and 2764 phosphopeptides detected per cell line. Of 4853 identified phosphopeptides with 4229 phosphosites, 4459 phosphopeptides (4430 pY) were linked to 3605 class I sites (3525 pY). INKA analysis in single cell lines successfully pinpointed driver kinases (PDGFRA, JAK2, KIT and FLT3) corresponding with activating mutations present in these cell lines. Furthermore, potential receptor tyrosine kinase (RTK) drivers, undetected by standard molecular analyses, were identified in four cell lines (FGFR1 in KG-1 and KG-1a, PDGFRA in Kasumi-3, and FLT3 in MM6). These cell lines proved highly sensitive to specific KIs. Six AML cell lines without a clear RTK driver showed evidence of MAPK1/3 activation, indicative of the presence of activating upstream RAS mutations. Importantly, FLT3 phosphorylation was demonstrated in two clinical AML samples with a FLT3 internal tandem duplication (ITD) mutation. Our data show the potential of pY-phosphoproteomics and INKA analysis to provide insight in AML TK signaling and identify hyperactive kinases as potential targets for treatment in AML cell lines. These results warrant future investigation of clinical samples to further our understanding of TK phosphorylation in relation to clinical response in the individual patient. Full Article
ca Identification of an Unconventional Subpeptidome Bound to the Behcet's Disease-associated HLA-B*51:01 that is Regulated by Endoplasmic Reticulum Aminopeptidase 1 (ERAP1) [Research] By feedproxy.google.com Published On :: 2020-05-01T00:05:26-07:00 Human leukocyte antigen (HLA) B*51:01 and endoplasmic reticulum aminopeptidase 1 (ERAP1) are strongly genetically associated with Behcet's disease (BD). Previous studies have defined two subgroups of HLA-B*51 peptidome containing proline (Pro) or alanine (Ala) at position 2 (P2). Little is known about the unconventional non-Pro/Ala2 HLA-B*51-bound peptides. We aimed to study the features of this novel subpeptidome, and investigate its regulation by ERAP1. CRISPR-Cas9 was used to generate an HLA-ABC-triple knockout HeLa cell line (HeLa.ABC-KO), which was subsequently transduced to express HLA-B*51:01 (HeLa.ABC-KO.B51). ERAP1 was silenced using lentiviral shRNA. Peptides bound to HLA-B*51:01 were eluted and analyzed by mass spectrometry. The characteristics of non-Pro/Ala2, Pro2, and Ala2 peptides and their alteration by ERAP1 silencing were investigated. Effects of ERAP1 silencing on cell surface expression of HLA-B*51:01 were studied using flow cytometry. More than 20% of peptides eluted from HLA-B*51:01 lacked Pro or Ala at P2. This unconventional group of HLA-B*51:01-bound peptides was relatively enriched for 8-mers (with relatively fewer 9-mers) compared with the Pro2 and Ala2 subpeptidomes and had similar N-terminal and C-terminal residue usages to Ala2 peptides (with the exception of the less abundant leucine at position ). Knockdown of ERAP1 increased the percentage of non-Pro/Ala2 from 20% to ~40%, increased the percentage of longer (10-mer and 11-mer) peptides eluted from HLA-B*51:01 complexes, and abrogated the predominance of leucine at P1. Interestingly knockdown of ERAP1 altered the length and N-terminal residue usage of non-Ala2&Pro2 and Ala2 but not the Pro2 peptides. Finally, ERAP1 silencing regulated the expression levels of cell surface HLA-B*51 in a cell-type-dependent manner. In conclusion, we have used a novel methodology to identify an unconventional but surprisingly abundant non-Pro/Ala2 HLA-B*51:01 subpeptidome. It is increased by knockdown of ERAP1, a gene affecting the risk of developing BD. This has implications for theories of disease pathogenesis. Full Article
ca Discovery of a Redox Thiol Switch: Implications for Cellular Energy Metabolism [Research] By feedproxy.google.com Published On :: 2020-05-01T00:05:26-07:00 The redox-based modifications of cysteine residues in proteins regulate their function in many biological processes. The gas molecule H2S has been shown to persulfidate redox sensitive cysteine residues resulting in an H2S-modified proteome known as the sulfhydrome. Tandem Mass Tags (TMT) multiplexing strategies for large-scale proteomic analyses have become increasingly prevalent in detecting cysteine modifications. Here we developed a TMT-based proteomics approach for selectively trapping and tagging cysteine persulfides in the cellular proteomes. We revealed the natural protein sulfhydrome of two human cell lines, and identified insulin as a novel substrate in pancreatic beta cells. Moreover, we showed that under oxidative stress conditions, increased H2S can target enzymes involved in energy metabolism by switching specific cysteine modifications to persulfides. Specifically, we discovered a Redox Thiol Switch, from protein S-glutathioinylation to S-persulfidation (RTSGS). We propose that the RTSGS from S-glutathioinylation to S-persulfidation is a potential mechanism to fine tune cellular energy metabolism in response to different levels of oxidative stress. Full Article
ca Quantitative Profiling of the Human Substantia Nigra Proteome from Laser-capture Microdissected FFPE Tissue [Research] By feedproxy.google.com Published On :: 2020-05-01T00:05:26-07:00 Laser-capture microdissection (LCM) allows the visualization and isolation of morphologically distinct subpopulations of cells from heterogeneous tissue specimens. In combination with formalin-fixed and paraffin-embedded (FFPE) tissue it provides a powerful tool for retrospective and clinically relevant studies of tissue proteins in a healthy and diseased context. We first optimized the protocol for efficient LCM analysis of FFPE tissue specimens. The use of SDS containing extraction buffer in combination with the single-pot solid-phase-enhanced sample preparation (SP3) digest method gave the best results regarding protein yield and protein/peptide identifications. Microdissected FFPE human substantia nigra tissue samples (~3,000 cells) were then analyzed, using tandem mass tag (TMT) labeling and LC-MS/MS, resulting in the quantification of >5,600 protein groups. Nigral proteins were classified and analyzed by abundance, showing an enrichment of extracellular exosome and neuron-specific gene ontology (GO) terms among the higher abundance proteins. Comparison of microdissected samples with intact tissue sections, using a label-free shotgun approach, revealed an enrichment of neuronal cell type markers, such as tyrosine hydroxylase and alpha-synuclein, as well as proteins annotated with neuron-specific GO terms. Overall, this study provides a detailed protocol for laser-capture proteomics using FFPE tissue and demonstrates the efficiency of LCM analysis of distinct cell subpopulations for proteomic analysis using low sample amounts. Full Article
ca The Secretome Profiling of a Pediatric Airway Epithelium Infected with hRSV Identified Aberrant Apical/Basolateral Trafficking and Novel Immune Modulating (CXCL6, CXCL16, CSF3) and Antiviral (CEACAM1) Proteins [Research] By feedproxy.google.com Published On :: 2020-05-01T00:05:26-07:00 The respiratory epithelium comprises polarized cells at the interface between the environment and airway tissues. Polarized apical and basolateral protein secretions are a feature of airway epithelium homeostasis. Human respiratory syncytial virus (hRSV) is a major human pathogen that primarily targets the respiratory epithelium. However, the consequences of hRSV infection on epithelium secretome polarity and content remain poorly understood. To investigate the hRSV-associated apical and basolateral secretomes, a proteomics approach was combined with an ex vivo pediatric human airway epithelial (HAE) model of hRSV infection (data are available via ProteomeXchange and can be accessed at https://www.ebi.ac.uk/pride/ with identifier PXD013661). Following infection, a skewing of apical/basolateral abundance ratios was identified for several individual proteins. Novel modulators of neutrophil and lymphocyte activation (CXCL6, CSF3, SECTM1 or CXCL16), and antiviral proteins (BST2 or CEACAM1) were detected in infected, but not in uninfected cultures. Importantly, CXCL6, CXCL16, CSF3 were also detected in nasopharyngeal aspirates (NPA) from hRSV-infected infants but not healthy controls. Furthermore, the antiviral activity of CEACAM1 against RSV was confirmed in vitro using BEAS-2B cells. hRSV infection disrupted the polarity of the pediatric respiratory epithelial secretome and was associated with immune modulating proteins (CXCL6, CXCL16, CSF3) never linked with this virus before. In addition, the antiviral activity of CEACAM1 against hRSV had also never been previously characterized. This study, therefore, provides novel insights into RSV pathogenesis and endogenous antiviral responses in pediatric airway epithelium. Full Article
ca A comprehensive evaluation of a typical plant telomeric G-quadruplex (G4) DNA reveals the dynamics of G4 formation, rearrangement, and unfolding [Plant Biology] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 Telomeres are specific nucleoprotein structures that are located at the ends of linear eukaryotic chromosomes and play crucial roles in genomic stability. Telomere DNA consists of simple repeats of a short G-rich sequence: TTAGGG in mammals and TTTAGGG in most plants. In recent years, the mammalian telomeric G-rich repeats have been shown to form G-quadruplex (G4) structures, which are crucial for modulating telomere functions. Surprisingly, even though plant telomeres are essential for plant growth, development, and environmental adaptions, only few reports exist on plant telomeric G4 DNA (pTG4). Here, using bulk and single-molecule assays, including CD spectroscopy, and single-molecule FRET approaches, we comprehensively characterized the structure and dynamics of a typical plant telomeric sequence, d[GGG(TTTAGGG)3]. We found that this sequence can fold into mixed G4s in potassium, including parallel and antiparallel structures. We also directly detected intermediate dynamic transitions, including G-hairpin, parallel G-triplex, and antiparallel G-triplex structures. Moreover, we observed that pTG4 is unfolded by the AtRecQ2 helicase but not by AtRecQ3. The results of our work shed light on our understanding about the existence, topological structures, stability, intermediates, unwinding, and functions of pTG4. Full Article
ca Biochemical and structural insights into how amino acids regulate pyruvate kinase muscle isoform 2 [Enzymology] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 Pyruvate kinase muscle isoform 2 (PKM2) is a key glycolytic enzyme involved in ATP generation and critical for cancer metabolism. PKM2 is expressed in many human cancers and is regulated by complex mechanisms that promote tumor growth and proliferation. Therefore, it is considered an attractive therapeutic target for modulating tumor metabolism. Various stimuli allosterically regulate PKM2 by cycling it between highly active and less active states. Several small molecules activate PKM2 by binding to its intersubunit interface. Serine and cysteine serve as an activator and inhibitor of PKM2, respectively, by binding to its amino acid (AA)-binding pocket, which therefore represents a potential druggable site. Despite binding similarly to PKM2, how cysteine and serine differentially regulate this enzyme remains elusive. Using kinetic analyses, fluorescence binding, X-ray crystallography, and gel filtration experiments with asparagine, aspartate, and valine as PKM2 ligands, we examined whether the differences in the side-chain polarity of these AAs trigger distinct allosteric responses in PKM2. We found that Asn (polar) and Asp (charged) activate PKM2 and that Val (hydrophobic) inhibits it. The results also indicate that both Asn and Asp can restore the activity of Val-inhibited PKM2. AA-bound crystal structures of PKM2 displayed distinctive interactions within the binding pocket, causing unique allosteric effects in the enzyme. These structure-function analyses of AA-mediated PKM2 regulation shed light on the chemical requirements in the development of mechanism-based small-molecule modulators targeting the AA-binding pocket of PKM2 and provide broader insights into the regulatory mechanisms of complex allosteric enzymes. Full Article
ca X-ray structures of catalytic intermediates of cytochrome c oxidase provide insights into its O2 activation and unidirectional proton-pump mechanisms [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-04-24T06:08:45-07:00 Cytochrome c oxidase (CcO) reduces O2 to water, coupled with a proton-pumping process. The structure of the O2-reduction site of CcO contains two reducing equivalents, Fea32+ and CuB1+, and suggests that a peroxide-bound state (Fea33+–O−–O−–CuB2+) rather than an O2-bound state (Fea32+–O2) is the initial catalytic intermediate. Unexpectedly, however, resonance Raman spectroscopy results have shown that the initial intermediate is Fea32+–O2, whereas Fea33+–O−–O−–CuB2+ is undetectable. Based on X-ray structures of static noncatalytic CcO forms and mutation analyses for bovine CcO, a proton-pumping mechanism has been proposed. It involves a proton-conducting pathway (the H-pathway) comprising a tandem hydrogen-bond network and a water channel located between the N- and P-side surfaces. However, a system for unidirectional proton-transport has not been experimentally identified. Here, an essentially identical X-ray structure for the two catalytic intermediates (P and F) of bovine CcO was determined at 1.8 Å resolution. A 1.70 Å Fe–O distance of the ferryl center could best be described as Fea34+ = O2−, not as Fea34+–OH−. The distance suggests an ∼800-cm−1 Raman stretching band. We found an interstitial water molecule that could trigger a rapid proton-coupled electron transfer from tyrosine-OH to the slowly forming Fea33+–O−–O−–CuB2+ state, preventing its detection, consistent with the unexpected Raman results. The H-pathway structures of both intermediates indicated that during proton-pumping from the hydrogen-bond network to the P-side, a transmembrane helix closes the water channel connecting the N-side with the hydrogen-bond network, facilitating unidirectional proton-pumping during the P-to-F transition. Full Article
ca Single-molecule level structural dynamics of DNA unwinding by human mitochondrial Twinkle helicase [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-04-24T06:08:45-07:00 Knowledge of the molecular events in mitochondrial DNA (mtDNA) replication is crucial to understanding the origins of human disorders arising from mitochondrial dysfunction. Twinkle helicase is an essential component of mtDNA replication. Here, we employed atomic force microscopy imaging in air and liquids to visualize ring assembly, DNA binding, and unwinding activity of individual Twinkle hexamers at the single-molecule level. We observed that the Twinkle subunits self-assemble into hexamers and higher-order complexes that can switch between open and closed-ring configurations in the absence of DNA. Our analyses helped visualize Twinkle loading onto and unloading from DNA in an open-ringed configuration. They also revealed that closed-ring conformers bind and unwind several hundred base pairs of duplex DNA at an average rate of ∼240 bp/min. We found that the addition of mitochondrial single-stranded (ss) DNA–binding protein both influences the ways Twinkle loads onto defined DNA substrates and stabilizes the unwound ssDNA product, resulting in a ∼5-fold stimulation of the apparent DNA-unwinding rate. Mitochondrial ssDNA-binding protein also increased the estimated translocation processivity from 1750 to >9000 bp before helicase disassociation, suggesting that more than half of the mitochondrial genome could be unwound by Twinkle during a single DNA-binding event. The strategies used in this work provide a new platform to examine Twinkle disease variants and the core mtDNA replication machinery. They also offer an enhanced framework to investigate molecular mechanisms underlying deletion and depletion of the mitochondrial genome as observed in mitochondrial diseases. Full Article
ca Biophysical characterization of SARAH domain-mediated multimerization of Hippo pathway complexes in Drosophila [Signal Transduction] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 Hippo pathway signaling limits cell growth and proliferation and maintains the stem-cell niche. These cellular events result from the coordinated activity of a core kinase cassette that is regulated, in part, by interactions involving Hippo, Salvador, and dRassF. These interactions are mediated by a conserved coiled-coil domain, termed SARAH, in each of these proteins. SARAH domain–mediated homodimerization of Hippo kinase leads to autophosphorylation and activation. Paradoxically, SARAH domain–mediated heterodimerization between Hippo and Salvador enhances Hippo kinase activity in cells, whereas complex formation with dRassF inhibits it. To better understand the mechanism by which each complex distinctly modulates Hippo kinase and pathway activity, here we biophysically characterized the entire suite of SARAH domain–mediated complexes. We purified the three SARAH domains from Drosophila melanogaster and performed an unbiased pulldown assay to identify all possible interactions, revealing that isolated SARAH domains are sufficient to recapitulate the cellular assemblies and that Hippo is a universal binding partner. Additionally, we found that the Salvador SARAH domain homodimerizes and demonstrate that this interaction is conserved in Salvador's mammalian homolog. Using native MS, we show that each of these complexes is dimeric in solution. We also measured the stability of each SARAH domain complex, finding that despite similarities at both the sequence and structural levels, SARAH domain complexes differ in stability. The identity, stoichiometry, and stability of these interactions characterized here comprehensively reveal the nature of SARAH domain–mediated complex formation and provide mechanistic insights into how SARAH domain–mediated interactions influence Hippo pathway activity. Full Article
ca Delineating an extracellular redox-sensitive module in T-type Ca2+ channels [Membrane Biology] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 T-type (Cav3) Ca2+ channels are important regulators of excitability and rhythmic activity of excitable cells. Among other voltage-gated Ca2+ channels, Cav3 channels are uniquely sensitive to oxidation and zinc. Using recombinant protein expression in HEK293 cells, patch clamp electrophysiology, site-directed mutagenesis, and homology modeling, we report here that modulation of Cav3.2 by redox agents and zinc is mediated by a unique extracellular module containing a high-affinity metal-binding site formed by the extracellular IS1–IS2 and IS3–IS4 loops of domain I and a cluster of extracellular cysteines in the IS1–IS2 loop. Patch clamp recording of recombinant Cav3.2 currents revealed that two cysteine-modifying agents, sodium (2-sulfonatoethyl) methanethiosulfonate (MTSES) and N-ethylmaleimide, as well as a reactive oxygen species–producing neuropeptide, substance P (SP), inhibit Cav3.2 current to similar degrees and that this inhibition is reversed by a reducing agent and a zinc chelator. Pre-application of MTSES prevented further SP-mediated current inhibition. Substitution of the zinc-binding residue His191 in Cav3.2 reduced the channel's sensitivity to MTSES, and introduction of the corresponding histidine into Cav3.1 sensitized it to MTSES. Removal of extracellular cysteines from the IS1–IS2 loop of Cav3.2 reduced its sensitivity to MTSES and SP. We hypothesize that oxidative modification of IS1–IS2 loop cysteines induces allosteric changes in the zinc-binding site of Cav3.2 so that it becomes sensitive to ambient zinc. Full Article
ca Atomic force microscopy-based characterization of the interaction of PriA helicase with stalled DNA replication forks [DNA and Chromosomes] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 In bacteria, the restart of stalled DNA replication forks requires the DNA helicase PriA. PriA can recognize and remodel abandoned DNA replication forks, unwind DNA in the 3'-to-5' direction, and facilitate the loading of the helicase DnaB onto the DNA to restart replication. Single-stranded DNA–binding protein (SSB) is typically present at the abandoned forks, but it is unclear how SSB and PriA interact, although it has been shown that the two proteins interact both physically and functionally. Here, we used atomic force microscopy to visualize the interaction of PriA with DNA substrates with or without SSB. These experiments were done in the absence of ATP to delineate the substrate recognition pattern of PriA before its ATP-catalyzed DNA-unwinding reaction. These analyses revealed that in the absence of SSB, PriA binds preferentially to a fork substrate with a gap in the leading strand. Such a preference has not been observed for 5'- and 3'-tailed duplexes, suggesting that it is the fork structure that plays an essential role in PriA's selection of DNA substrates. Furthermore, we found that in the absence of SSB, PriA binds exclusively to the fork regions of the DNA substrates. In contrast, fork-bound SSB loads PriA onto the duplex DNA arms of forks, suggesting a remodeling of PriA by SSB. We also demonstrate that the remodeling of PriA requires a functional C-terminal domain of SSB. In summary, our atomic force microscopy analyses reveal key details in the interactions between PriA and stalled DNA replication forks with or without SSB. Full Article
ca Tracking isotopically labeled oxidants using boronate-based redox probes [Methods and Resources] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Reactive oxygen and nitrogen species have been implicated in many biological processes and diseases, including immune responses, cardiovascular dysfunction, neurodegeneration, and cancer. These chemical species are short-lived in biological settings, and detecting them in these conditions and diseases requires the use of molecular probes that form stable, easily detectable, products. The chemical mechanisms and limitations of many of the currently used probes are not well-understood, hampering their effective applications. Boronates have emerged as a class of probes for the detection of nucleophilic two-electron oxidants. Here, we report the results of an oxygen-18–labeling MS study to identify the origin of oxygen atoms in the oxidation products of phenylboronate targeted to mitochondria. We demonstrate that boronate oxidation by hydrogen peroxide, peroxymonocarbonate, hypochlorite, or peroxynitrite involves the incorporation of oxygen atoms from these oxidants. We therefore conclude that boronates can be used as probes to track isotopically labeled oxidants. This suggests that the detection of specific products formed from these redox probes could enable precise identification of oxidants formed in biological systems. We discuss the implications of these results for understanding the mechanism of conversion of the boronate-based redox probes to oxidant-specific products. Full Article
ca Templated folding of intrinsically disordered proteins [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Much of our current knowledge of biological chemistry is founded in the structure-function relationship, whereby sequence determines structure that determines function. Thus, the discovery that a large fraction of the proteome is intrinsically disordered, while being functional, has revolutionized our understanding of proteins and raised new and interesting questions. Many intrinsically disordered proteins (IDPs) have been determined to undergo a disorder-to-order transition when recognizing their physiological partners, suggesting that their mechanisms of folding are intrinsically different from those observed in globular proteins. However, IDPs also follow some of the classic paradigms established for globular proteins, pointing to important similarities in their behavior. In this review, we compare and contrast the folding mechanisms of globular proteins with the emerging features of binding-induced folding of intrinsically disordered proteins. Specifically, whereas disorder-to-order transitions of intrinsically disordered proteins appear to follow rules of globular protein folding, such as the cooperative nature of the reaction, their folding pathways are remarkably more malleable, due to the heterogeneous nature of their folding nuclei, as probed by analysis of linear free-energy relationship plots. These insights have led to a new model for the disorder-to-order transition in IDPs termed “templated folding,” whereby the binding partner dictates distinct structural transitions en route to product, while ensuring a cooperative folding. Full Article
ca Crystallographic and kinetic analyses of the FdsBG subcomplex of the cytosolic formate dehydrogenase FdsABG from Cupriavidus necator [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Formate oxidation to carbon dioxide is a key reaction in one-carbon compound metabolism, and its reverse reaction represents the first step in carbon assimilation in the acetogenic and methanogenic branches of many anaerobic organisms. The molybdenum-containing dehydrogenase FdsABG is a soluble NAD+-dependent formate dehydrogenase and a member of the NADH dehydrogenase superfamily. Here, we present the first structure of the FdsBG subcomplex of the cytosolic FdsABG formate dehydrogenase from the hydrogen-oxidizing bacterium Cupriavidus necator H16 both with and without bound NADH. The structures revealed that the two iron-sulfur clusters, Fe4S4 in FdsB and Fe2S2 in FdsG, are closer to the FMN than they are in other NADH dehydrogenases. Rapid kinetic studies and EPR measurements of rapid freeze-quenched samples of the NADH reduction of FdsBG identified a neutral flavin semiquinone, FMNH•, not previously observed to participate in NADH-mediated reduction of the FdsABG holoenzyme. We found that this semiquinone forms through the transfer of one electron from the fully reduced FMNH−, initially formed via NADH-mediated reduction, to the Fe2S2 cluster. This Fe2S2 cluster is not part of the on-path chain of iron-sulfur clusters connecting the FMN of FdsB with the active-site molybdenum center of FdsA. According to the NADH-bound structure, the nicotinamide ring stacks onto the re-face of the FMN. However, NADH binding significantly reduced the electron density for the isoalloxazine ring of FMN and induced a conformational change in residues of the FMN-binding pocket that display peptide-bond flipping upon NAD+ binding in proper NADH dehydrogenases. Full Article
ca Quantification of the affinities of CRISPR-Cas9 nucleases for cognate protospacer adȷacent motif (PAM) sequences [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 The CRISPR/Cas9 nucleases have been widely applied for genome editing in various organisms. Cas9 nucleases complexed with a guide RNA (Cas9–gRNA) find their targets by scanning and interrogating the genomic DNA for sequences complementary to the gRNA. Recognition of the DNA target sequence requires a short protospacer adjacent motif (PAM) located outside this sequence. Given that the efficiency of target location may depend on the strength of interactions that promote target recognition, here we sought to compare affinities of different Cas9 nucleases for their cognate PAM sequences. To this end, we measured affinities of Cas9 nucleases from Streptococcus pyogenes, Staphylococcus aureus, and Francisella novicida complexed with guide RNAs (gRNAs) (SpCas9–gRNA, SaCas9–gRNA, and FnCas9–gRNA, respectively) and of three engineered SpCas9–gRNA variants with altered PAM specificities for short, PAM-containing DNA probes. We used a “beacon” assay that measures the relative affinities of DNA probes by determining their ability to competitively affect the rate of Cas9–gRNA binding to fluorescently labeled target DNA derivatives called “Cas9 beacons.” We observed significant differences in the affinities for cognate PAM sequences among the studied Cas9 enzymes. The relative affinities of SpCas9–gRNA and its engineered variants for canonical and suboptimal PAMs correlated with previous findings on the efficiency of these PAM sequences in genome editing. These findings suggest that high affinity of a Cas9 nuclease for its cognate PAM promotes higher genome-editing efficiency. Full Article
ca A neuroglobin-based high-affinity ligand trap reverses carbon monoxide-induced mitochondrial poisoning [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Carbon monoxide (CO) remains the most common cause of human poisoning. The consequences of CO poisoning include cardiac dysfunction, brain injury, and death. CO causes toxicity by binding to hemoglobin and by inhibiting mitochondrial cytochrome c oxidase (CcO), thereby decreasing oxygen delivery and inhibiting oxidative phosphorylation. We have recently developed a CO antidote based on human neuroglobin (Ngb-H64Q-CCC). This molecule enhances clearance of CO from red blood cells in vitro and in vivo. Herein, we tested whether Ngb-H64Q-CCC can also scavenge CO from CcO and attenuate CO-induced inhibition of mitochondrial respiration. Heart tissue from mice exposed to 3% CO exhibited a 42 ± 19% reduction in tissue respiration rate and a 33 ± 38% reduction in CcO activity compared with unexposed mice. Intravenous infusion of Ngb-H64Q-CCC restored respiration rates to that of control mice correlating with higher electron transport chain CcO activity in Ngb-H64Q-CCC–treated compared with PBS-treated, CO-poisoned mice. Further, using a Clark-type oxygen electrode, we measured isolated rat liver mitochondrial respiration in the presence and absence of saturating solutions of CO (160 μm) and nitric oxide (100 μm). Both CO and NO inhibited respiration, and treatment with Ngb-H64Q-CCC (100 and 50 μm, respectively) significantly reversed this inhibition. These results suggest that Ngb-H64Q-CCC mitigates CO toxicity by scavenging CO from carboxyhemoglobin, improving systemic oxygen delivery and reversing the inhibitory effects of CO on mitochondria. We conclude that Ngb-H64Q-CCC or other CO scavengers demonstrate potential as antidotes that reverse the clinical and molecular effects of CO poisoning. Full Article
ca Making the Business Case for Nutrition Workshop By feedproxy.google.com Published On :: Thu, 05 Dec 2019 12:15:01 +0000 Invitation Only Research Event 28 January 2020 - 9:30am to 5:00pm Chatham House | 10 St James's Square | London | SW1Y 4LE A ground-breaking research project from Chatham House, supported by The Power of Nutrition, is exploring the business case for tackling undernutrition, micronutrient deficiencies and overnutrition. Companies across all sectors hold huge, transformative power to save countless lives and transform their own financial prospects. To act, they need more compelling evidence of the potential for targeted investments and strategies to promote better nutrition and create healthier, more productive workforces and consumers.At this workshop, Chatham House will engage business decision-makers in a scenario exercise that explores different nutrition futures and their commercial prospects in each before examining what different strategies business can pursue to maximize future profitability through investments in nutrition.Attendance at this event is by invitation only. Department/project Energy, Environment and Resources Programme Full Article
ca Just Circular Economy Transitions in Latin America By feedproxy.google.com Published On :: Tue, 10 Dec 2019 14:40:01 +0000 Invitation Only Research Event 11 December 2019 - 9:00am to 12 December 2019 - 5:00pm Montevideo, Uruguay To identify and promote collaborative opportunities for an inclusive and sustainable circular economy transition at the international level, a clearer understanding and discussions of the potential winners and losers of such a transition is needed. In short, a ‘win-win-win’ vision for the environment, people and the economy, needs to be built and credible pathways to achieving this vision.This research workshop, organized by Chatham House and UNIDO, will build on previous and ongoing research by Chatham House, and others, to drive forward an inclusive circular economy agenda and promote a just transition from linear to circular economic models. Chatham House, in collaboration with partners, aims to provide a strong evidence base of the opportunities and trade-offs in this transition from linear to circular models by robustly analysing the political economies in key regions in the developing world and engaging with leading stakeholders from governments, international organizations, civil society and the business community.Latin America is an important geographical region for the circular economy especially in view of the circular bioeconomy and the agenda around inclusiveness. Several countries are beginning to embrace the circular economy concept and related policies. This workshop will bring together circular economy leaders from policy, business and civil society across Latin American countries to identify and discuss challenges, large-scale positive sum opportunities, investment needs, existing alliances and the potential to scale up circular economy practices. The second day of the workshop includes site visits to various circular economy projects in Uruguay.Attendance at this event is by invitation only. Department/project Energy, Environment and Resources Programme, Building Transformative Alliances for an Inclusive Global Circular Economy Melissa MacEwen Project Manager, Energy, Environment and Resources Programme Email Full Article
ca Subsidies and Sustainable Agriculture: Mapping the Policy Landscape By feedproxy.google.com Published On :: Tue, 10 Dec 2019 18:36:21 +0000 11 December 2019 Agricultural subsidies shape production and consumption patterns, with potentially significant effects on poverty, nutrition and other sustainability concerns. This paper maps the different types of support provided by governments to the agricultural sector, and highlights some of the complex political economy dynamics that underpin the relevant policies. Download PDF Christophe Bellmann Associate Fellow, Hoffmann Centre for Sustainable Resource Economy, Chatham House 2019-12-06-Wheat-Field-China.jpg Aerial view of a wheat field on 24 May 2019 in Linyi, Shandong Province of China. Photo: Getty Images. SummaryAgricultural subsidies, a mainstay of government policy, have a large part in shaping production and consumption patterns, with potentially significant effects as regards poverty, food security, nutrition, and other sustainability concerns such as climate change, land use practices and biodiversity.There are multiple types of direct and indirect support provided by governments to various actors in the agricultural sector; and in terms of political economy, there are complex dynamics underpinning the policies that sustain these subsidies.Overall, subsidies targeting producers have the most significant effect on production, and the greater trade-distorting effect. These subsidies promote domestic production and discourage imports, leading to overproduction that is largely disposed of on the international market, with the help of export subsidies. This can tend to intensify negative environmental agricultural practices, such as cultivating marginal land, unsustainable types of intensification, or incentivizing excessive pesticide and fertilizer use.On the other hand, producer subsidies that are not tied to output of a specific commodity (i.e. delinked) have far fewer distorting impacts and could help to deliver sustainable outcomes. For example, this type of subsidies can require crop diversification or be linked to conservation of permanent grassland.Subsidies that enable transfers to consumers, for example through food stamp programmes, also serve to delink production from consumption, can foster healthier diets, can play an important role in delivering food accessibility and security among low-income groups, and can represent one of the less trade-distorting subsidies.If subsidies are to be reformed to help promote healthier diets and encourage more sustainable production, it is essential to understand not only the type and amount of support that key countries provide, but also the domestic dynamics that can shape such policies.While price support, input subsidies or investment aids remain the central pillars of programmes in large developing countries such as Brazil, China or India, other economies – notably including the EU and Japan – focus on direct payments, support for general services and set-aside schemes, as well as significant border protection. The US, for its part, has tended to focus on subsidized insurance schemes and food programmes for poorer consumers.If subsidies are to deliver policy objectives, their design and implementation should delink production from consumption. For example, consumer subsidies designed to deliver nutrition and food security, or payments for environmental services to enable more environmentally friendly production systems, could prove to be the most effective, least trade-distorting means of achieving more sustainable and equitable agricultural production.The political economy of food means that the removal of subsidies is often highly sensitive, and tends to be met with significant resistance. However, reform that delinks support from production through a gradual transition process could ultimately prove successful in delivering effective subsidy schemes.Effective subsidy schemes must by design be truly result- and performance-based, supported by robust and objective indicators. At the same time, engaging multiple actors along key commodity value chains – including leading importing and exporting countries, traders and transporters – could lead to the development of international, commodity-specific arrangements that are able to deliver effective nutrition and sustainability goals. Full Article
ca Net Zero and Beyond: What Role for Bioenergy with Carbon Capture and Storage? By feedproxy.google.com Published On :: Mon, 06 Jan 2020 13:55:01 +0000 Invitation Only Research Event 23 January 2020 - 8:30am to 10:00am Chatham House | 10 St James's Square | London | SW1Y 4LE Event participants Richard King, Senior Research Fellow, Energy, Environment and Resources Department, Chatham HouseChair: Duncan Brack, Associate Fellow, Energy, Environment and Resources Department, Chatham House In the context of the feasibility of reducing greenhouse gas emissions to net zero, policymakers are beginning to pay more attention to options for removing carbon dioxide from the atmosphere. A wide range of potential carbon dioxide removal (CDR) options are currently being discussed and modelled though the most prominent among them are bioenergy with carbon capture and storage (BECCS) and afforestation and reforestation.There are many reasons to question the reliance on BECCS assumed in the models including the carbon balances achievable, its substantial needs for land, water and other inputs and technically and economically viable carbon capture and storage technologies.This meeting will examine the potentials and challenges of BECCS in the context of other CDR and emissions abatement options. It will discuss the requisite policy and regulatory frameworks to minimize sustainability and socio-political risks of CDR approaches while also avoiding overshooting climate goals.Attendance at this event is by invitation only. Event attributes Chatham House Rule Department/project Energy, Environment and Resources Programme, Sustainable Transitions Series Chloé Prendleloup Email Full Article
ca Review essay: Where is the Anthropocene? IR in a new geological epoch By feedproxy.google.com Published On :: Wed, 08 Jan 2020 13:46:10 +0000 8 January 2020 , Volume 96, Number 1 Read online Dahlia Simangan Several disciplines outside the natural sciences, including International Relations (IR), have engaged with the Anthropocene discourse in order to theorize their relevance and translate their practical value in this new phase of the Earth's history. Some IR scholars have called for a post-humanist IR, planet politics, a cosmopolitan view, and ecological security, among other approaches, to recalibrate the theoretical foundations of the discipline, making it more attuned to the realities of the Anthropocene. Existing discussions, however, tend to universalize human experience and gravitate towards western ontologies and epistemologies of living in the Anthropocene. Within this burgeoning scholarship, how is the IR discipline engaging with the Anthropocene discourse? Although the Anthropocene has become a new theoretical landscape for the conceptual broadening of conventional IR subjects, this review reveals the need for sustained discussion that highlights the differentiated human experiences in the Anthropocene. The existing IR publications on the Anthropocene locates the non-spatial narratives of vulnerability and historical injustice, the non-modernist understanding of nature, the agency of the vulnerable, and the amplification of security issues in the Anthropocene. It is in amplifying these narratives that the IR discipline can broaden and diversify the discourse on the Anthropocene and, therefore, affirm its relevance in this new geological age. Full Article
ca Forecasting Forum 2020 By feedproxy.google.com Published On :: Wed, 15 Jan 2020 15:35:01 +0000 Invitation Only Research Event 17 February 2020 - 2:00pm to 5:00pm Chatham House | 10 St James's Square | London | SW1Y 4LE Event participants Professor Tim Benton, Research Director, Emerging Risks; Director, Energy, Environment and Resources Programme, Chatham HouseProfessor Paul Stevens, Distinguished Fellow, Energy, Environment and Resources Programme, Chatham HouseAntony Froggatt, Senior Research Fellow, Energy, Environment and Resources Programme, Chatham HouseChair: Glada Lahn, Senior Research Fellow, Energy, Environment and Resources Programme The Forecasting Forum 2020 will present the latest thinking from the Chatham House Energy, Environment and Resources Department's senior research team on the dynamics that will affect fossil fuel and energy investments and markets in the year ahead.14:00 - 14:30 | Introduction and Climate Risks Outlook In the last decade, following the financial crisis, the literature on systemic risks has grown. Systemic risks occur when complex, non-linear, interconnected systems fail, often through relatively small perturbations, as their impacts cascade and amplify across the system. Within this context, climate change is a 'threat multiplier' with the risks increasing in scale, frequency and magnitude. Just as complex systems can pass thresholds and tip from a functional state to a non-functional state, so can societies and people’s attitudes. Together risk cascades or systemic risks and attitudinal tipping points have the potential to rapidly change the way the world works. Professor Tim Benton will open the Forecasting Forum 2020 with reflections on what this might mean for the pace and linearity of the fossil fuel transition.14:30 - 15:30 | Session 1: An Outlook on Oil Prices in 2020In this session, Professor Paul Stevens will argue that the recent events associated with the assassination of Iranian General Qasem Soleimani have exacerbated the sensitivity of oil markets to political events and brought 'geopolitics' back into global oil prices. Up to 2014, geopolitics played a key role in determining oil prices in the paper markets where perceptions and expectations ruled. By 2014, the world was so oversupplied with real oil barrels that the oil price collapsed and little attention was given to geopolitical events as geopolitics became marginalized in the determination of crude oil prices. However, recent events in the Middle East suggest that prices will become increasingly volatile but, at the same time, benefit from a rising geopolitical premium.15:45 - 16:45 | Session 2: An Outlook for Energy in 2020Recent years have brought significant disruption to the European power sector. Not only are many of Europe’s major utilities restructuring their businesses in light of decarbonization and technological developments but Brexit has distracted - and detracted from - efforts to create more systemic energy linkages between the UK and the rest of Europe. During his presentation, Antony Froggatt will draw on his ongoing research to outline what he believes are the prevailing challenges and opportunities for the European power sector over the coming year while highlighting some of the most significant global trends.Please note, attendance at this event is by invitation only. Event attributes Chatham House Rule Department/project Energy, Environment and Resources Programme, Sustainable Transitions Series Chloé Prendleloup Email Full Article
ca Net Zero and Beyond: What Role for Bioenergy with Carbon Capture and Storage? By feedproxy.google.com Published On :: Wed, 29 Jan 2020 11:51:45 +0000 29 January 2020 Policymakers are in danger of sleepwalking into ineffective carbon dioxide removal solutions in the quest to tackle climate change. This paper warns against overreliance on bioenergy with carbon capture and storage (BECCS). Read online Download PDF Duncan Brack Associate Fellow, Energy, Environment and Resources Programme @DuncanBrack Google Scholar Richard King Senior Research Fellow, Energy, Environment and Resources Programme LinkedIn Reaching Net Zero: Does BECCS Work? Policymakers can be influenced by ineffective carbon dioxide removal solutions in the quest to tackle climate change. This animation explores the risks of using bioenergy with carbon capture and storage (BECCS). SummaryCurrent climate efforts are not progressing quickly enough to prevent the world from overshooting the global emissions targets set in the Paris Agreement; accordingly, attention is turning increasingly to options for removing carbon dioxide from the atmosphere – ‘carbon dioxide removal’ (CDR). Alongside afforestation and reforestation, the main option under discussion is bioenergy with carbon capture and storage (BECCS): processes through which the carbon emissions from burning biomass for energy are captured before release into the atmosphere and stored in underground reservoirs.This pre-eminent status is not, however, based on a comprehensive analysis of the feasibility and impacts of BECCS. In reality, BECCS has many drawbacks.Models generally assume that biomass for energy is inherently carbon-neutral (and thus that BECCS, by capturing and storing the emissions from combustion, is carbon-negative), but in reality this is not a valid assumption.On top of this, the deployment of BECCS at the scales assumed in most models would consume land on a scale comparable to half that currently taken up by global cropland, entailing massive land-use change, potentially endangering food security and biodiversity. There is also significant doubt about the likely energy output of BECCS solutions.BECCS may still have some role to play in strategies for CDR, depending mainly on the feedstock used; but it should be evaluated on the same basis as other CDR options, such as nature-based solutions or direct air carbon capture and storage (DACCS). Analysis should take full account of carbon balances over time, the requirements of each CDR option in terms of demand for land, water and other inputs, and the consequences of that demand.There is an urgent need for policymakers to engage with these debates. The danger at the moment is that policymakers are ‘sleepwalking towards BECCS’ simply because most models incorporate it – or, almost as bad, it may be that they are simply ignoring the need for any meaningful action on CDR as a whole. Department/project Energy, Environment and Resources Programme, Bioenergy, Carbon Capture and Storage (BECCS) Full Article
ca The prospects of carbon dioxide removal in climate policymaking within the United States By feedproxy.google.com Published On :: Fri, 14 Feb 2020 10:40:01 +0000 Research Event 19 November 2019 - 9:00am to 5:00pm School of Law, University of California, Davis Agendapdf | 158.8 KB Meeting Summarypdf | 207.92 KB This meeting formed part of a programme of work which investigates the role of negative emissions technologies (NETs) in achieving the Paris Agreement climate targets. Previous meetings held in London and Brussels have looked at integrating negative emissions into EU policy-making, the implications and degree to which NETs, and in particular bioenergy with carbon capture storage (BECCS), can be an effective climate mitigation tool. This meeting focused on the possible deployment pathways of NETs and alternatives to BECCS for the US in particular, in the context of geographical constraints and socioenvironmental implications, the role of the private sector, and appropriate governance and finance mechanisms. Department/project Energy, Environment and Resources Programme, Bioenergy, Carbon Capture and Storage (BECCS) Melissa MacEwen Project Manager, Energy, Environment and Resources Programme Email Full Article
ca Global aid and faith actors: the case for an actor-orientated approach to the ‘turn to religion’ By feedproxy.google.com Published On :: Wed, 04 Mar 2020 13:00:22 +0000 4 March 2020 , Volume 96, Number 2 Emma Tomalin Read Online In this article, drawing on the work of the development sociologist Norman Long, I make the case for an actor-oriented approach to understanding the ‘turn to religion’ by global aid actors over the past couple of decades. I ask, is the ‘turn to religion’ evidence of the emergence of post-secular partnerships or are faith actors being instrumentalized to serve neo-liberal development goals? I argue that neither option captures the whole story and advocate that the study of religion and development needs to move beyond a binary between the ‘turn to religion’ as either evidence of post-secular partnerships or of the ‘instrumentalization’ of religion by the secular global aid business, and instead to think about how faith actors themselves encounter and shape development discourses and frameworks, translate them into relevant formats and strategically employ them. Alongside the adoption of an actor-orientated approach, I build on the work of Lewis and Mosse, Olivier de Sardan and Bierschenk to view international faith-based organizations (IFBOs) as development brokers and translators. This approach allows me to articulate the distinctive role that many members of IFBOs report they play as intermediaries who shift register between the secular development language and the faith-inspired language of their local faith partners. I take the engagement of faith actors with the new Sustainable Development Goals framework as a case-study to explore this. Full Article
ca Privileging Local Food is Flawed Solution to Reduce Emissions By feedproxy.google.com Published On :: Thu, 23 Apr 2020 13:59:11 +0000 23 April 2020 Christophe Bellmann Associate Fellow, Hoffmann Centre for Sustainable Resource Economy LinkedIn The COVID-19 pandemic has brought food security and food imports to the forefront again. Some fear that the crisis could quickly strain global food supply chains as countries adopt new trade restrictions to avoid domestic food shortages. 2020-04-23-Trade-Food-Apples Apples being picked before going into cold storage so they can be bought up until Christmas. Photo by Suzanne Kreiter/The Boston Globe via Getty Images. The pressure of the coronavirus pandemic is adding to a widely held misconception that trade in food products is bad for the environment due to the associated ‘food miles’ – the carbon footprint of agricultural products transported over long distances.This concept, developed by large retailers a decade ago, is often invoked as a rationale for restricting trade and choosing locally-produced food over imports. Consuming local food may seem sensible at first glance as it reduces the carbon footprint of goods and generates local employment. However, this assumption ignores the emissions produced during the production, processing or storage stages which often dwarf transport emissions. Other avenues to address the climate change impact of trade are more promising.Demystifying food emissionsIn the US, for example, food items travel more than 8,000 km on average before reaching the consumer. Yet transport only accounts for 11 per cent of total emissions with 83 per cent – mostly nitrous oxide (N2O) and methane (CH4) emissions – occurring at the production stage.US Department of Agriculture data on energy use in the American food system echoes this finding, showing that processing, packaging, and selling of food represent ten times the energy used to transport food.In practice, it may be preferable from an environmental perspective to consume lamb, onion or dairy products transported by sea because the lower emissions generated at the production stage offset those resulting from transport. Similarly, growing tomatoes under heated greenhouses in Sweden is often more emissions-intensive than importing open-grown ones from Southern Europe.Seasonality also matters. British apples placed in storage for ten months leads to twice the level of emissions as that of South American apples sea-freighted to the UK. And the type of transport is also important as, overall, maritime transport generates 25 to 250 times less emissions than trucks, and air freight generates on average five times more emissions than road transport.Therefore, air-freighted Kenyan beans have a much larger carbon footprint than those produced in the UK, but crossing Europe by truck to import Italian wine might generate more emissions than transatlantic shipments.Finally, one should take into account the last leg of transport. A consumer driving more than 10 km to purchase 1 kg of fresh produce will generate proportionately more greenhouse gas (GHG) emissions than air-freighting 1 kg of produce from Kenya.Shifting consumption towards local foods may reduce GHG emissions in sectors with relatively low emissions intensities but, when non-carbon dioxide emissions are taken into account, this is more often the exception than the rule.Under these circumstances, preventing trade is an inefficient and expensive way of reducing GHG emissions. Bureau et al. for example, calculate that a global tariff maintaining the volume of trade at current levels until 2030 may reduce global carbon dioxide emissions by 3.5 per cent. However, this would be roughly seven times less than the full implementation of the Paris Agreement and cost equivalent to the current GDP of Brazil or 1.8 per cent of world GDP.By preventing an efficient use of resources, such restrictions would also undermine the role of trade in offsetting possible climate-induced production shortfalls in some parts of the world and allowing people to access food when they can’t produce it themselves.Reducing the climate footprint of tradeThis is not to say that nothing should be done to tackle transport emissions. The OECD estimates that international trade-related freight accounted for over 5 per cent of total global fuel emissions with shipping representing roughly half of it, trucks 40 per cent, air 6 per cent and rail 2 per cent. With the projected tripling of freight transport by 2050, emissions from shipping are expected to rise between 50 and 250 per cent.Furthermore, because of their international nature, these emissions are not covered by the Paris Agreement. Instead the two UN agencies regulating these sectors – the International Civil Aviation Organization and the International Maritime Organization – are responsible for reducing these emissions and, so far, significant progress has proven elusive.Regional or bilateral free trade agreements to further stimulate trade could address this problem by exploiting comparative advantages. Impact assessments of those agreements often point towards increases in GHG emissions due to a boost in trade flows. In the future, such agreements could incorporate – or develop in parallel – initiatives to ensure carbon neutrality by connecting carbon markets among contracting parties or by taxing international maritime and air transport emissions.Such initiatives could be combined with providing additional preferences in the form of enhanced market access to low-carbon food and healthier food. The EU, as one of the chief proponents of bilateral and regional trade agreements and a leader in promoting a transition to a low-carbon economy could champion such an approach.This article is part of a series from the Chatham House Global Trade Policy Forum, designed to promote research and policy recommendations on the future of global trade. It is adapted from the research paper, Delivering Sustainable Food and Land Use Systems: The Role of International Trade, authored by Christophe Bellmann, Bernice Lee and Jonathan Hepburn. Full Article
ca Episode 16: The Caveman Episode By feedproxy.google.com Published On :: Fri, 14 Dec 2012 06:17:00 +0000 Quest For Fire10,000 B.C.What We WatchedMiscellaneous BanterDownload the episode here. (right click to save) Full Article
ca Episode 37: The Hunger Games: Catching Fire & The Wolverine By feedproxy.google.com Published On :: Wed, 27 Nov 2013 06:36:00 +0000 The Hunger Games: Catching Fire reviewThe Wolverine ReviewsWhat We Watched: jOBS, Steve Jobs: The Lost Interview, WWE For All Mankind: Life and Career of Mick Foley and The Lakota 38You can download the episode here. (right click to save) You can subscribe to us on iTunes here. Full Article