377 research outputs found

    Public questions spur the discovery of new bacterial species associated with lignin bioconversion of industrial waste

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    A citizen science project found that the greenhouse camel cricket (Diestrammena asynamora) is common in North American homes. Public response was to wonder “what good are they anyway?” and ecology and evolution guided the search for potential benefit. We predicted that camel crickets and similar household species would likely host bacteria with the ability to degrade recalcitrant carbon compounds. Lignocellulose is particularly relevant as it is difficult to degrade yet is an important feedstock for pulp and paper, chemical, and biofuel industries. We screened gut bacteria of greenhouse camel crickets and another household insect, a hide beetle (Dermestes maculatus) for the ability to grow on and degrade lignocellulose components as well as the lignocellulose-derived industrial waste product black liquor. From three greenhouse camel crickets and three hide beetles, 14 bacterial strains were identified capable of growth on lignocellulosic components, including lignin. Cedecea lapagei was selected for further study due to growth on most lignocellulose components. The C. lapagei secretome was identified using LC/MS/MS analysis. This work demonstrates a novel source of lignocellulose-degrading bacteria and introduces an effective workflow to identify bacterial enzymes for transforming industrial waste into value-added products. More generally, our research suggests the value of ecologically-guided discovery of novel organisms

    Resonant X-ray emission spectroscopy reveals d–d ligand-field states involved in the self-assembly of a square-planar platinum complex

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    Resonant X-ray Emission Spectroscopy (RXES) is used to characterize the ligand field states of the prototypic self-assembled square-planar complex, [Pt(tpy)Cl]Cl (tpy=2,2′:6′,2′′-terpyridine), and determine the effect of weak metal-metal and π-π interactions on their energy. © 2012 the Owner Societies

    Marx - From Hegel and Feuerbach to Adam Smith : a New Sysnthesis

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    In The Economic and Philosophical Manuscripts of 1844 (completed in August 1844) Marx takes two crucial steps in the formation of his worldview. The first relates to his rejection of all 'old' materialism, including Feuerbach's, and the adoption of his own version, which he called 'communist', 'practical'. This view was later presented definitively in the first Thesis on Feuerbach (spring of 1845), and elaborated in The German Ideology (1845-46). The second step relates to Marx's synthesising of the philosophical standpoint that he had developed up to this point (around the spring of 1844) with political economy. Up to this point he had spoken of alienation in largely philosophical terms; now it is rooted in the process of production. On both counts Adam Smith was an important influence. This claim provides the focus of this paper. To make this point successfully I have found it necessary to briefly trace the development of Marx's philosophical standpoint up to the writing of the Manuscripts, and to distinguish between the two methodologically distinct aspects of Adam Smith's thought, the one that Marx accepted and the other that he rejected

    The Arabidopsis leucine-rich repeat receptor kinase BIR3 negatively regulates BAK1 receptor complex formation and stabilizes BAK1

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    BAK1 is a co-receptor and positive regulator of multiple ligand-binding leucine-rich-repeat receptor kinases (LRR-RKs) and is involved in brassinosteroid (BR)-dependent growth and development, innate immunity and cell death control. The BAK1-interacting LRR-RKs BIR2 and BIR3 were previously identified by proteomics analyses of in vivo BAK1 complexes. Here we show that BAK1-related pathways such as innate immunity and cell death control are affected by BIR3 in Arabidopsis thaliana. BIR3 also has a strong negative impact on BR signaling. BIR3 directly interacts with the BR receptor BRI1 and other ligand-binding receptors and negatively regulates BR signaling by competitive inhibition of BRI1. BIR3 is released from BAK1 and BRI1 after ligand exposure and directly affects the formation of BAK1 complexes with BRI1 or FLAGELLIN SENSING2. Double mutants of bak1 and bir3 show spontaneous cell death and constitutive activation of defense responses. BAK1 and its closest homolog BKK1 interact with and are stabilized by BIR3, suggesting that bak1 bir3 double mutants mimic the spontaneous cell death phenotype observed in bak1 bkk1 mutants via destabilization of BIR3 target proteins. Our results provide evidence for a negative regulatory mechanism for BAK1 receptor complexes in which BIR3 interacts with BAK1 and inhibits ligand-binding receptors to prevent BAK1 receptor complex formation

    Autophosphorylation-based calcium (Ca2+) sensitivity priming and Ca2+/Calmodulin inhibition of Arabidopsis thaliana Ca2+-dependent protein kinase 28 (CPK28)

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    Plant calcium (Ca2+) dependent protein kinases (CPKs) are composed of a dual specificity (Ser/Thr and Tyr) kinase domain tethered to a Calmodulin-like domain (CLD) via an autoinhibitory junction (J) and represent the primary Ca2+-dependent protein kinase activities in plant systems. While regulation of CPKs by Ca2+ has been extensively studied, the contribution of autophosphorylation in the control of CPK activity is less well understood. Furthermore, whether Calmodulin (CaM) contributes to CPK regulation, as is the case for Ca2+/CaM-dependent protein kinases (CaMKs) outside the plant lineage, remains an open question. We screened a subset of plant CPKs for CaM-binding and found that CPK28 is a high-affinity Ca2+/CaM-binding protein. Using synthetic peptides and native gel electrophoresis, we coarsely mapped the CaM-binding domain to a site within the CPK28 J domain that overlaps with the known site of intramolecular interaction between the J domain and CLD. Peptide kinase activity of fully dephosphorylated CPK28 was Ca2+-responsive and inhibited by Ca2+/CaM. Using in situ autophosphorylated protein, we expand on the known set of CPK28 autophosphorylation sites, and demonstrate that, unexpectedly, autophosphorylated CPK28 had enhanced activity at physiological concentrations of Ca2+ compared to dephosphorylated protein, suggesting that autophosphorylation functions to prime CPK28 for Ca2+-activation. Furthermore, CPK28 autophosphorylation substantially reduced sensitivity of the kinase to Ca2+/CaM inhibition. Overall, our analyses uncover new complexities in the control of CPK28 and provide mechanistic support for Ca2+ signaling specificity through Ca2+ sensor priming

    Computing H/D-Exchange rates of single residues from data of proteolytic fragments

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    <p>Abstract</p> <p>Background</p> <p>Protein conformation and protein/protein interaction can be elucidated by solution-phase Hydrogen/Deuterium exchange (sHDX) coupled to high-resolution mass analysis of the digested protein or protein complex. In sHDX experiments mutant proteins are compared to wild-type proteins or a ligand is added to the protein and compared to the wild-type protein (or mutant). The number of deuteriums incorporated into the polypeptides generated from the protease digest of the protein is related to the solvent accessibility of amide protons within the original protein construct.</p> <p>Results</p> <p>In this work, sHDX data was collected on a 14.5 T FT-ICR MS. An algorithm was developed based on combinatorial optimization that predicts deuterium exchange with high spatial resolution based on the sHDX data of overlapping proteolytic fragments. Often the algorithm assigns deuterium exchange with single residue resolution.</p> <p>Conclusions</p> <p>With our new method it is possible to automatically determine deuterium exchange with higher spatial resolution than the level of digested fragments.</p
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