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  • 1
    ISSN: 1432-0789
    Keywords: Decomposition ; Immobilization ; Mineralization ; Bamboo savanna ; Litter types ; Lignin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Decomposition and changes in nutrient content of six litter types (leaves, sheaths, roots, twigs, and wood of bamboo, and grass shoots) were studied in nylon net bags for 2 years. The annual weight loss was (% of initial) bamboo leaves 56.5, bamboo sheaths 79.5, bamboo roots 65.8, bamboo twigs 49.6, bamboo wood 31.2, and grass shoots 74.9. Elemental mobility followed the order K〉Na〉C〉P〉Ca〉N in all components except wood. Generally, an initial increase was followed by a consistent decrease in the contents of N (leaves), P (leaves, roots, wood) and Ca (leaves, roots, grass), and Na (wood). Most of the nutrients were immobilized in the rainy season. C and K contents showed a constant decrease throughout the decomposition period. Materials with a greater C:N ratio (〉50) tended to accumulate more nutrients and retain them for longer, except for the bamboo twigs. The critical C:N ratio (at which a net release of N occured) for the leaf material was 25. Litter components with more initial N (sheaths) showed greater weight loss than those with less N (leaves, twigs, and wood). Overall, N and P were lost at the slowest rates while C and K were lost at faster rates. Initial lignin, lignin: N, C:N and C concentrations had a better predictive value for annual weight loss and nutrient release in bivariate relationships. A combination of the initial lignin value and the C: N ratio explained 93% of the variation in annual weight loss. A significant relationship was also observed between the annual weight loss rate and the nutrient mineralization/release rate.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0789
    Keywords: Perionyx excavatus ; Earthworms ; Feeding activity ; Plant residues ; Mineralization ; Maturity parameters ; Vermicomposting ; C/N ratio ; Straw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An outdoor study was undertaken using polyethylene containers to assess the suitability of different organic residues, soybean straw (Glycine max L. Merril.), wheat straw (Triticum aestivum L.), maize stover (Zea mays L.), chickpea straw (citer arietinum L.) and city garbage, as food for the tropical epigeic earthwormPerionyx excavatus, and to assess the influence of this earthworm on the decomposition of these materials. Maize stover was found to be the most suitable of the food materials used. Population growth ofP. excavatus was enhanced by addition of these organic materials in the temperature range 24°-30°C, while the population was adversely affected above 30°C in a vermiculture system. Addition of earthworms accelerated the breakdown of residues, which ultimately resulted in a lowering of the C:N ratio, water-soluble carbon and carbohydrates, and increased ash percentage and cation exchange capacity compared with their respective controls.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0789
    Keywords: Key wordsPerionyx excavatus ; Earthworms ; Feeding activity ; Plant residues ; Mineralization ; Maturity parameters ; Vermicomposting ; C/N ratio ; Straw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An outdoor study was undertaken using polyethylene containers to assess the suitability of different organic residues, soybean straw (Glycine max L. Merril.), wheat straw (Triticum aestivum L.), maize stover (Zea mays L.), chickpea straw (cicer arietinum L.) and city garbage, as food for the tropical epigeic earthworm Perionyx excavatus, and to assess the influence of this earthworm on the decomposition of these materials. Maize stover was found to be the most suitable of the food materials used. Population growth of P. excavatus was enhanced by addition of these organic materials in the temperature range 24°–30°C, while the population was adversely affected above 30°C in a vermiculture system. Addition of earthworms accelerated the breakdown of residues, which ultimately resulted in a lowering of the C:N ratio, water-soluble carbon and carbohydrates, and increased ash percentage and cation exchange capacity compared with their respective controls.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2013-07-23
    Description: Aberrant neovascularization contributes to diseases such as cancer, blindness and atherosclerosis, and is the consequence of inappropriate angiogenic signalling. Although many regulators of pathogenic angiogenesis have been identified, our understanding of this process is incomplete. Here we explore the transcriptome of retinal microvessels isolated from mouse models of retinal disease that exhibit vascular pathology, and uncover an upregulated gene, leucine-rich alpha-2-glycoprotein 1 (Lrg1), of previously unknown function. We show that in the presence of transforming growth factor-beta1 (TGF-beta1), LRG1 is mitogenic to endothelial cells and promotes angiogenesis. Mice lacking Lrg1 develop a mild retinal vascular phenotype but exhibit a significant reduction in pathological ocular angiogenesis. LRG1 binds directly to the TGF-beta accessory receptor endoglin, which, in the presence of TGF-beta1, results in promotion of the pro-angiogenic Smad1/5/8 signalling pathway. LRG1 antibody blockade inhibits this switch and attenuates angiogenesis. These studies reveal a new regulator of angiogenesis that mediates its effect by modulating TGF-beta signalling.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836402/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836402/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wang, Xiaomeng -- Abraham, Sabu -- McKenzie, Jenny A G -- Jeffs, Natasha -- Swire, Matthew -- Tripathi, Vineeta B -- Luhmann, Ulrich F O -- Lange, Clemens A K -- Zhai, Zhenhua -- Arthur, Helen M -- Bainbridge, James W B -- Moss, Stephen E -- Greenwood, John -- 091886/Wellcome Trust/United Kingdom -- G0902206/Medical Research Council/United Kingdom -- G1000466/Medical Research Council/United Kingdom -- NIHR-RP-011-003/Department of Health/United Kingdom -- RG/12/2/29416/British Heart Foundation/United Kingdom -- British Heart Foundation/United Kingdom -- Medical Research Council/United Kingdom -- Wellcome Trust/United Kingdom -- England -- Nature. 2013 Jul 18;499(7458):306-11. doi: 10.1038/nature12345.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, UCL Institute of Ophthalmology, London EC1V 9EL, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23868260" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cells, Cultured ; Endothelium, Vascular/cytology/*metabolism ; Glycoproteins/genetics/metabolism/*physiology ; In Vitro Techniques ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Receptors, Transforming Growth Factor beta/metabolism ; Retinal Neovascularization/genetics/*metabolism ; Retinal Vessels/metabolism ; *Signal Transduction ; Transforming Growth Factor beta1/*metabolism/pharmacology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2013-04-23
    Description: The functions of G-protein-coupled receptors (GPCRs) are primarily mediated and modulated by three families of proteins: the heterotrimeric G proteins, the G-protein-coupled receptor kinases (GRKs) and the arrestins. G proteins mediate activation of second-messenger-generating enzymes and other effectors, GRKs phosphorylate activated receptors, and arrestins subsequently bind phosphorylated receptors and cause receptor desensitization. Arrestins activated by interaction with phosphorylated receptors can also mediate G-protein-independent signalling by serving as adaptors to link receptors to numerous signalling pathways. Despite their central role in regulation and signalling of GPCRs, a structural understanding of beta-arrestin activation and interaction with GPCRs is still lacking. Here we report the crystal structure of beta-arrestin-1 (also called arrestin-2) in complex with a fully phosphorylated 29-amino-acid carboxy-terminal peptide derived from the human V2 vasopressin receptor (V2Rpp). This peptide has previously been shown to functionally and conformationally activate beta-arrestin-1 (ref. 5). To capture this active conformation, we used a conformationally selective synthetic antibody fragment (Fab30) that recognizes the phosphopeptide-activated state of beta-arrestin-1. The structure of the beta-arrestin-1-V2Rpp-Fab30 complex shows marked conformational differences in beta-arrestin-1 compared to its inactive conformation. These include rotation of the amino- and carboxy-terminal domains relative to each other, and a major reorientation of the 'lariat loop' implicated in maintaining the inactive state of beta-arrestin-1. These results reveal, at high resolution, a receptor-interacting interface on beta-arrestin, and they indicate a potentially general molecular mechanism for activation of these multifunctional signalling and regulatory proteins.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3654799/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3654799/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shukla, Arun K -- Manglik, Aashish -- Kruse, Andrew C -- Xiao, Kunhong -- Reis, Rosana I -- Tseng, Wei-Chou -- Staus, Dean P -- Hilger, Daniel -- Uysal, Serdar -- Huang, Li-Yin -- Paduch, Marcin -- Tripathi-Shukla, Prachi -- Koide, Akiko -- Koide, Shohei -- Weis, William I -- Kossiakoff, Anthony A -- Kobilka, Brian K -- Lefkowitz, Robert J -- GM072688/GM/NIGMS NIH HHS/ -- GM087519/GM/NIGMS NIH HHS/ -- HL 075443/HL/NHLBI NIH HHS/ -- HL16037/HL/NHLBI NIH HHS/ -- HL70631/HL/NHLBI NIH HHS/ -- NS028471/NS/NINDS NIH HHS/ -- P41 RR011823/RR/NCRR NIH HHS/ -- R01 HL016037/HL/NHLBI NIH HHS/ -- R01 HL070631/HL/NHLBI NIH HHS/ -- R01 NS028471/NS/NINDS NIH HHS/ -- U01 GM094588/GM/NIGMS NIH HHS/ -- U54 GM074946/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2013 May 2;497(7447):137-41. doi: 10.1038/nature12120. Epub 2013 Apr 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23604254" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arrestins/*chemistry/immunology/*metabolism ; Crystallography, X-Ray ; Humans ; Immunoglobulin Fab Fragments/chemistry/immunology/metabolism ; Models, Molecular ; Phosphopeptides/*chemistry/*metabolism ; Phosphorylation ; Protein Binding ; Protein Conformation ; Protein Stability ; Rats ; Receptors, Vasopressin/*chemistry ; Rotation
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2014-07-22
    Description: G-protein-coupled receptors (GPCRs) are critically regulated by beta-arrestins, which not only desensitize G-protein signalling but also initiate a G-protein-independent wave of signalling. A recent surge of structural data on a number of GPCRs, including the beta2 adrenergic receptor (beta2AR)-G-protein complex, has provided novel insights into the structural basis of receptor activation. However, complementary information has been lacking on the recruitment of beta-arrestins to activated GPCRs, primarily owing to challenges in obtaining stable receptor-beta-arrestin complexes for structural studies. Here we devised a strategy for forming and purifying a functional human beta2AR-beta-arrestin-1 complex that allowed us to visualize its architecture by single-particle negative-stain electron microscopy and to characterize the interactions between beta2AR and beta-arrestin 1 using hydrogen-deuterium exchange mass spectrometry (HDX-MS) and chemical crosslinking. Electron microscopy two-dimensional averages and three-dimensional reconstructions reveal bimodal binding of beta-arrestin 1 to the beta2AR, involving two separate sets of interactions, one with the phosphorylated carboxy terminus of the receptor and the other with its seven-transmembrane core. Areas of reduced HDX together with identification of crosslinked residues suggest engagement of the finger loop of beta-arrestin 1 with the seven-transmembrane core of the receptor. In contrast, focal areas of raised HDX levels indicate regions of increased dynamics in both the N and C domains of beta-arrestin 1 when coupled to the beta2AR. A molecular model of the beta2AR-beta-arrestin signalling complex was made by docking activated beta-arrestin 1 and beta2AR crystal structures into the electron microscopy map densities with constraints provided by HDX-MS and crosslinking, allowing us to obtain valuable insights into the overall architecture of a receptor-arrestin complex. The dynamic and structural information presented here provides a framework for better understanding the basis of GPCR regulation by arrestins.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134437/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134437/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shukla, Arun K -- Westfield, Gerwin H -- Xiao, Kunhong -- Reis, Rosana I -- Huang, Li-Yin -- Tripathi-Shukla, Prachi -- Qian, Jiang -- Li, Sheng -- Blanc, Adi -- Oleskie, Austin N -- Dosey, Anne M -- Su, Min -- Liang, Cui-Rong -- Gu, Ling-Ling -- Shan, Jin-Ming -- Chen, Xin -- Hanna, Rachel -- Choi, Minjung -- Yao, Xiao Jie -- Klink, Bjoern U -- Kahsai, Alem W -- Sidhu, Sachdev S -- Koide, Shohei -- Penczek, Pawel A -- Kossiakoff, Anthony A -- Woods, Virgil L Jr -- Kobilka, Brian K -- Skiniotis, Georgios -- Lefkowitz, Robert J -- DK090165/DK/NIDDK NIH HHS/ -- GM072688/GM/NIGMS NIH HHS/ -- GM087519/GM/NIGMS NIH HHS/ -- GM60635/GM/NIGMS NIH HHS/ -- HL075443/HL/NHLBI NIH HHS/ -- HL16037/HL/NHLBI NIH HHS/ -- HL70631/HL/NHLBI NIH HHS/ -- MOP-93725/Canadian Institutes of Health Research/Canada -- NS028471/NS/NINDS NIH HHS/ -- R01 DK090165/DK/NIDDK NIH HHS/ -- R01 GM060635/GM/NIGMS NIH HHS/ -- R01 GM072688/GM/NIGMS NIH HHS/ -- R01 HL016037/HL/NHLBI NIH HHS/ -- R01 HL070631/HL/NHLBI NIH HHS/ -- R01 NS028471/NS/NINDS NIH HHS/ -- UL1 TR000430/TR/NCATS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2014 Aug 14;512(7513):218-22. doi: 10.1038/nature13430. Epub 2014 Jun 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA [2] Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India. [3]. ; 1] Life Sciences Institute and Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA [2]. ; 1] Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA [2]. ; Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA. ; Department of Chemistry, University of California at San Diego, La Jolla, California 92093, USA. ; Life Sciences Institute and Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA. ; School of Pharmaceutical &Life Sciences, Changzhou University, Changzhou, Jiangsu 213164, China. ; Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. ; Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA. ; Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA. ; Department of Biochemistry and Molecular Biology, The University of Texas Medical School at Houston, Houston, Texas 77054, USA. ; 1] Department of Chemistry, University of California at San Diego, La Jolla, California 92093, USA [2]. ; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA. ; 1] Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA [2] Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA [3] Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25043026" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arrestins/*chemistry/*metabolism ; GTP-Binding Proteins/chemistry/metabolism ; *Models, Molecular ; Protein Structure, Quaternary ; Receptors, Adrenergic, beta-2/chemistry/metabolism ; Receptors, G-Protein-Coupled/*chemistry/*metabolism ; Sf9 Cells
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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