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Sample records for oligomeric death domain

  1. Assembly of Oligomeric Death Domain Complexes during Toll Receptor Signaling*

    OpenAIRE

    Moncrieffe, Martin C.; Grossmann, J. Günter; Gay, Nicholas J.

    2008-01-01

    The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show ...

  2. Assembly of Oligomeric Death Domain Complexes during Toll Receptor Signaling*

    Science.gov (United States)

    Moncrieffe, Martin C.; Grossmann, J. Günter; Gay, Nicholas J.

    2008-01-01

    The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show that both the heterodimeric and heterotrimeric complexes form kidney-shaped structures and that Tube is bivalent and has separate high affinity binding sites for dMyD88 and Pelle. Additionally we found no interaction between the isolated death domains of Pelle and dMyD88. These results indicate that the mode of assembly of the heterotrimeric dMyD88-Tube-Pelle complex downstream of the activated Toll receptor is unique. The measured dissociation constants for the interaction between the death domains of dMyD88 and Tube and of Pelle and a preformed dMyD88-Tube complex are used to propose a model of the early postreceptor events in Drosophila Toll receptor signaling. PMID:18829464

  3. Assembly of oligomeric death domain complexes during Toll receptor signaling.

    Science.gov (United States)

    Moncrieffe, Martin C; Grossmann, J Günter; Gay, Nicholas J

    2008-11-28

    The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show that both the heterodimeric and heterotrimeric complexes form kidney-shaped structures and that Tube is bivalent and has separate high affinity binding sites for dMyD88 and Pelle. Additionally we found no interaction between the isolated death domains of Pelle and dMyD88. These results indicate that the mode of assembly of the heterotrimeric dMyD88-Tube-Pelle complex downstream of the activated Toll receptor is unique. The measured dissociation constants for the interaction between the death domains of dMyD88 and Tube and of Pelle and a preformed dMyD88-Tube complex are used to propose a model of the early postreceptor events in Drosophila Toll receptor signaling.

  4. Lack of Both Nucleotide-Binding Oligomerization Domain-Containing Proteins 1 and 2 Primes T Cells for Activation-Induced Cell Death.

    Science.gov (United States)

    Kasimsetty, Sashi G; Shigeoka, Alana A; Scheinok, Andrew A; Gavin, Amanda L; Ulevitch, Richard J; McKay, Dianne B

    2017-08-01

    Nucleotide-binding oligomerization domain (Nod)-containing proteins Nod1 and Nod2 play important roles in the innate immune response to pathogenic microbes, but mounting data suggest these pattern recognition receptors might also play key roles in adaptive immune responses. Targeting Nod1 and Nod2 signaling pathways in T cells is likely to provide a new strategy to modify inflammation in a variety of disease states, particularly those that depend on Ag-induced T cell activation. To better understand how Nod1 and Nod2 proteins contribute to adaptive immunity, this study investigated their role in alloantigen-induced T cell activation and asked whether their absence might impact in vivo alloresponses using a severe acute graft versus host disease model. The study provided several important observations. We found that the simultaneous absence of Nod1 and Nod2 primed T cells for activation-induced cell death. T cells from Nod1 × 2 -/- mice rapidly underwent cell death upon exposure to alloantigen. The Nod1 × 2 -/- T cells had sustained p53 expression that was associated with downregulation of its negative regulator MDM2. In vivo, mice transplanted with an inoculum containing Nod1 × 2 -/- T cells were protected from severe graft versus host disease. The results show that the simultaneous absence of Nod1 and Nod2 is associated with accelerated T cell death upon alloantigen encounter, suggesting these proteins might provide new targets to ameliorate T cell responses in a variety of inflammatory states, including those associated with bone marrow or solid organ transplantation. Copyright © 2017 by The American Association of Immunologists, Inc.

  5. Different domains are critical for oligomerization compatibility of different connexins

    Science.gov (United States)

    MARTÍNEZ, Agustín D.; MARIPILLÁN, Jaime; ACUÑA, Rodrigo; MINOGUE, Peter J.; BERTHOUD, Viviana M.; BEYER, Eric C.

    2011-01-01

    Oligomerization of connexins is a critical step in gap junction channel formation. Some members of the connexin family can oligomerize with other members and form functional heteromeric hemichannels [e.g. Cx43 (connexin 43) and Cx45], but others are incompatible (e.g. Cx43 and Cx26). To find connexin domains important for oligomerization, we constructed chimaeras between Cx43 and Cx26 and studied their ability to oligomerize with wild-type Cx43, Cx45 or Cx26. HeLa cells co-expressing Cx43, Cx45 or Cx26 and individual chimaeric constructs were analysed for interactions between the chimaeras and the wild-type connexins using cell biological (subcellular localization by immunofluorescence), functional (intercellular diffusion of microinjected Lucifer yellow) and biochemical (sedimentation velocity through sucrose gradients) assays. All of the chimaeras containing the third transmembrane domain of Cx43 interacted with wild-type Cx43 on the basis of co-localization, dominant-negative inhibition of intercellular communication, and altered sedimentation velocity. The same chimaeras also interacted with co-expressed Cx45. In contrast, immunofluorescence and intracellular diffusion of tracer suggested that other domains influenced oligomerization compatibility when chimaeras were co-expressed with Cx26. Taken together, these results suggest that amino acids in the third transmembrane domain are critical for oligomerization with Cx43 and Cx45. However, motifs in different domains may determine oligomerization compatibility in members of different connexin subfamilies. PMID:21348854

  6. Crystal Structure of the Marburg Virus VP35 Oligomerization Domain

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, Jessica F.; Kirchdoerfer, Robert N.; Urata, Sarah M.; Li, Sheng; Tickle, Ian J.; Bricogne, Gérard; Saphire, Erica Ollmann (Scripps); (Globel Phasing); (UCSD)

    2016-11-09

    ABSTRACT

    Marburg virus (MARV) is a highly pathogenic filovirus that is classified in a genus distinct from that of Ebola virus (EBOV) (generaMarburgvirusandEbolavirus, respectively). Both viruses produce a multifunctional protein termed VP35, which acts as a polymerase cofactor, a viral protein chaperone, and an antagonist of the innate immune response. VP35 contains a central oligomerization domain with a predicted coiled-coil motif. This domain has been shown to be essential for RNA polymerase function. Here we present crystal structures of the MARV VP35 oligomerization domain. These structures and accompanying biophysical characterization suggest that MARV VP35 is a trimer. In contrast, EBOV VP35 is likely a tetramer in solution. Differences in the oligomeric state of this protein may explain mechanistic differences in replication and immune evasion observed for MARV and EBOV.

    IMPORTANCEMarburg virus can cause severe disease, with up to 90% human lethality. Its genome is concise, only producing seven proteins. One of the proteins, VP35, is essential for replication of the viral genome and for evasion of host immune responses. VP35 oligomerizes (self-assembles) in order to function, yet the structure by which it assembles has not been visualized. Here we present two crystal structures of this oligomerization domain. In both structures, three copies of VP35 twist about each other to form a coiled coil. This trimeric assembly is in contrast to tetrameric predictions for VP35 of Ebola virus and to known structures of homologous proteins in the measles, mumps, and Nipah viruses. Distinct oligomeric states of the Marburg and Ebola virus VP35 proteins may explain differences between them in polymerase function and immune evasion. These findings may provide a more accurate understanding of the

  7. Diverse oligomeric states of CEACAM IgV domains.

    Science.gov (United States)

    Bonsor, Daniel A; Günther, Sebastian; Beadenkopf, Robert; Beckett, Dorothy; Sundberg, Eric J

    2015-11-03

    Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) comprise a large family of cell surface adhesion molecules that bind to themselves and other family members to carry out numerous cellular functions, including proliferation, signaling, differentiation, tumor suppression, and survival. They also play diverse and significant roles in immunity and infection. The formation of CEACAM oligomers is caused predominantly by interactions between their N-terminal IgV domains. Although X-ray crystal structures of CEACAM IgV domain homodimers have been described, how CEACAMs form heterodimers or remain monomers is poorly understood. To address this key aspect of CEACAM function, we determined the crystal structures of IgV domains that form a homodimeric CEACAM6 complex, monomeric CEACAM8, and a heterodimeric CEACAM6-CEACAM8 complex. To confirm and quantify these interactions in solution, we used analytical ultracentrifugation to measure the dimerization constants of CEACAM homodimers and isothermal titration calorimetry to determine the thermodynamic parameters and binding affinities of CEACAM heterodimers. We found the CEACAM6-CEACAM8 heterodimeric state to be substantially favored energetically relative to the CEACAM6 homodimer. Our data provide a molecular basis for the adoption of the diverse oligomeric states known to exist for CEACAMs and suggest ways in which CEACAM6 and CEACAM8 regulate the biological functions of one another, as well as of additional CEACAMs with which they interact, both in cis and in trans.

  8. Domain architecture and oligomerization properties of the paramyxovirus PIV 5 hemagglutinin-neuraminidase (HN) protein.

    Science.gov (United States)

    Yuan, Ping; Leser, George P; Demeler, Borries; Lamb, Robert A; Jardetzky, Theodore S

    2008-09-01

    The mechanism by which the paramyxovirus hemagglutinin-neuraminidase (HN) protein couples receptor binding to activation of virus entry remains to be fully understood, but the HN stalk is thought to play an important role in the process. We have characterized ectodomain constructs of the parainfluenza virus 5 HN to understand better the underlying architecture and oligomerization properties that may influence HN functions. The PIV 5 neuraminidase (NA) domain is monomeric whereas the ectodomain forms a well-defined tetramer. The HN stalk also forms tetramers and higher order oligomers with high alpha-helical content. Together, the data indicate that the globular NA domains form weak intersubunit interactions at the end of the HN stalk tetramer, while stabilizing the stalk and overall oligomeric state of the ectodomain. Electron microscopy of the HN ectodomain reveals flexible arrangements of the NA and stalk domains, which may be important for understanding how these two HN domains impact virus entry.

  9. Multi-PAS domain-mediated protein oligomerization of PpsR from Rhodobacter sphaeroides

    International Nuclear Information System (INIS)

    Heintz, Udo; Meinhart, Anton; Winkler, Andreas

    2014-01-01

    Crystal structures of two truncated variants of the transcription factor PpsR from R. sphaeroides are presented that enabled the phasing of a triple PAS domain construct. Together, these structures reveal the importance of α-helical PAS extensions for multi-PAS domain-mediated protein oligomerization and function. Per–ARNT–Sim (PAS) domains are essential modules of many multi-domain signalling proteins that mediate protein interaction and/or sense environmental stimuli. Frequently, multiple PAS domains are present within single polypeptide chains, where their interplay is required for protein function. Although many isolated PAS domain structures have been reported over the last decades, only a few structures of multi-PAS proteins are known. Therefore, the molecular mechanism of multi-PAS domain-mediated protein oligomerization and function is poorly understood. The transcription factor PpsR from Rhodobacter sphaeroides is such a multi-PAS domain protein that, in addition to its three PAS domains, contains a glutamine-rich linker and a C-terminal helix–turn–helix DNA-binding motif. Here, crystal structures of two N-terminally and C-terminally truncated PpsR variants that comprise a single (PpsR Q-PAS1 ) and two (PpsR N-Q-PAS1 ) PAS domains, respectively, are presented and the multi-step strategy required for the phasing of a triple PAS domain construct (PpsR ΔHTH ) is illustrated. While parts of the biologically relevant dimerization interface can already be observed in the two shorter constructs, the PpsR ΔHTH structure reveals how three PAS domains enable the formation of multiple oligomeric states (dimer, tetramer and octamer), highlighting that not only the PAS cores but also their α-helical extensions are essential for protein oligomerization. The results demonstrate that the long helical glutamine-rich linker of PpsR results from a direct fusion of the N-cap of the PAS1 domain with the C-terminal extension of the N-domain that plays an important

  10. DC-SIGN neck domain is a pH-sensor controlling oligomerization: SAXS and hydrodynamic studies of extracellular domain.

    Science.gov (United States)

    Tabarani, Georges; Thépaut, Michel; Stroebel, David; Ebel, Christine; Vivès, Corinne; Vachette, Patrice; Durand, Dominique; Fieschi, Franck

    2009-08-07

    DC-SIGN is a C-type lectin receptor of dendritic cells and is involved in the early stages of numerous infectious diseases. DC-SIGN is organized into a tetramer enabling multivalent interaction with pathogens. Once formed, the DC-SIGN-pathogen complex can be internalized into compartments of increasing acidity. We have studied the pH dependence of the oligomerization state and conformation of the entire extracellular domain and neck region. We present evidence for equilibrium between the monomeric and tetrameric states of the extracellular domain, which exhibits a marked dependence with respect to both pH and ionic strength. Using solution x-ray scattering we have obtained a molecular envelope of the extracellular domain in which a model has been built. Our results highlight the central role of the neck domain in the pH-sensitive control of the oligomerization state, in the extended conformation of the protein, and in carbohydrate recognition domain organization and presentation. This work opens new insight into the molecular mechanism of ligand release and points to new avenues to block the first step of this important infection pathway.

  11. Assembly of the intrinsic factor domains and oligomerization of the protein in the presence of cobalamin

    DEFF Research Database (Denmark)

    Fedosov, Sergey N; Fedosova, Natalya U; Berglund, Lars

    2004-01-01

    oligomerized. A mixture of two fragments IF(30) + IF(20) and Cbl produced a firm complex, IF(30+20).Cbl, which could not associate to dimers. In contrast to IF(30+20).Cbl, the saturated full-length monomers IF(50).Cbl dimerized with K(d) approximately 1 microM. We suggest a two-domain organization of the full......-length protein, where two distant units, IF(30) and IF(20), can be assembled only by Cbl. They are connected by a protease-sensitive link, whose native structure is likely to be important for dimerization. However, linkage between two domains is not compulsory for Cbl binding. Advantages of the two...

  12. Nucleotide-binding oligomerization domain 2 (NOD2) activation induces apoptosis of human oral squamous cell carcinoma cells.

    Science.gov (United States)

    Yoon, Hyo-Eun; Ahn, Mee-Young; Kwon, Seong-Min; Kim, Dong-Jae; Lee, Jun; Yoon, Jung-Hoon

    2016-04-01

    Microbial Pattern-recognition receptors (PRRs), such as nucleotide-binding oligomerization domains (NODs), are essential for mammalian innate immune response. This study was designed to determine the effect of NOD1 and NOD2 agonist on innate immune responses and antitumor activity in oral squamous cell carcinoma (OSCC) cells. NODs expression was examined by RT-PCR, and IL-8 production by NODs agonist was examined by ELISA. Western blot analysis was performed to determine the MAPK activation in response to their agonist. Cell proliferation was determined by MTT assay. Flow cytometry and Western blot analysis were performed to determine the MDP-induced cell death. The levels of NODs were apparently expressed in OSCC cells. NODs agonist, Tri-DAP and MDP, led to the production of IL-8 and MAPK activation. NOD2 agonist, MDP, inhibited the proliferation of YD-10B cells in a dose-dependent manner. Also, the ratio of Annexin V-positive cells and cleaved PARP was increased by MDP treatment in YD-10B cells, suggesting that MDP-induced cell death in YD-10B cells may be owing to apoptosis. Our results indicate that NODs are functionally expressed in OSCC cells and can trigger innate immune responses. In addition, NOD2 agonist inhibited cell proliferation and induced apoptosis. These findings provide the potential value of MDP as novel candidates for antitumor agents of OSCC. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Complex structure of the fission yeast SREBP-SCAP binding domains reveals an oligomeric organization.

    Science.gov (United States)

    Gong, Xin; Qian, Hongwu; Shao, Wei; Li, Jingxian; Wu, Jianping; Liu, Jun-Jie; Li, Wenqi; Wang, Hong-Wei; Espenshade, Peter; Yan, Nieng

    2016-11-01

    Sterol regulatory element-binding protein (SREBP) transcription factors are master regulators of cellular lipid homeostasis in mammals and oxygen-responsive regulators of hypoxic adaptation in fungi. SREBP C-terminus binds to the WD40 domain of SREBP cleavage-activating protein (SCAP), which confers sterol regulation by controlling the ER-to-Golgi transport of the SREBP-SCAP complex and access to the activating proteases in the Golgi. Here, we biochemically and structurally show that the carboxyl terminal domains (CTD) of Sre1 and Scp1, the fission yeast SREBP and SCAP, form a functional 4:4 oligomer and Sre1-CTD forms a dimer of dimers. The crystal structure of Sre1-CTD at 3.5 Å and cryo-EM structure of the complex at 5.4 Å together with in vitro biochemical evidence elucidate three distinct regions in Sre1-CTD required for Scp1 binding, Sre1-CTD dimerization and tetrameric formation. Finally, these structurally identified domains are validated in a cellular context, demonstrating that the proper 4:4 oligomeric complex formation is required for Sre1 activation.

  14. A Small-Molecule Inhibitor of Bax and Bak Oligomerization Prevents Genotoxic Cell Death and Promotes Neuroprotection.

    Science.gov (United States)

    Niu, Xin; Brahmbhatt, Hetal; Mergenthaler, Philipp; Zhang, Zhi; Sang, Jing; Daude, Michael; Ehlert, Fabian G R; Diederich, Wibke E; Wong, Eve; Zhu, Weijia; Pogmore, Justin; Nandy, Jyoti P; Satyanarayana, Maragani; Jimmidi, Ravi K; Arya, Prabhat; Leber, Brian; Lin, Jialing; Culmsee, Carsten; Yi, Jing; Andrews, David W

    2017-04-20

    Aberrant apoptosis can lead to acute or chronic degenerative diseases. Mitochondrial outer membrane permeabilization (MOMP) triggered by the oligomerization of the Bcl-2 family proteins Bax/Bak is an irreversible step leading to execution of apoptosis. Here, we describe the discovery of small-molecule inhibitors of Bax/Bak oligomerization that prevent MOMP. We demonstrate that these molecules disrupt multiple, but not all, interactions between Bax dimer interfaces thereby interfering with the formation of higher-order oligomers in the MOM, but not recruitment of Bax to the MOM. Small-molecule inhibition of Bax/Bak oligomerization allowed cells to evade apoptotic stimuli and rescued neurons from death after excitotoxicity, demonstrating that oligomerization of Bax is essential for MOMP. Our discovery of small-molecule Bax/Bak inhibitors provides novel tools for the investigation of the mechanisms leading to MOMP and will ultimately facilitate development of compounds inhibiting Bax/Bak in acute and chronic degenerative diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Molecular cloning and functional characterization of duck nucleotide-binding oligomerization domain 1 (NOD1).

    Science.gov (United States)

    Li, Huilin; Jin, Hui; Li, Yaqian; Liu, Dejian; Foda, Mohamed Frahat; Jiang, Yunbo; Luo, Rui

    2017-09-01

    Nucleotide-binding oligomerization domain 1 (NOD1) is an imperative cytoplasmic pattern recognition receptor (PRR) and considered as a key member of the NOD-like receptor (NLR) family which plays a critical role in innate immunity through sensing microbial components derived from bacterial peptidoglycan. In the current study, the full-length of duck NOD1 (duNOD1) cDNA from duck embryo fibroblasts (DEFs) was cloned. Multiple sequence alignment and phylogenetic analysis demonstrated that duNOD1 exhibited a strong evolutionary relationship with chicken and rock pigeon NOD1. Tissue-specific expression analysis showed that duNOD1 was widely distributed in various organs, with the highest expression observed in the liver. Furthermore, duNOD1 overexpression induced NF-κB activation in DEFs and the CARD domain is crucial for duNOD1-mediated NF-κB activation. In addition, silencing the duNOD1 decreased the activity of NF-κB in DEFs stimulated by iE-DAP. Overexpression of duNOD1 significantly increased the expression of TNF-α, IL-6, and RANTES in DEFs. These findings highlight the crucial role of duNOD1 as an intracellular sensor in duck innate immune system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Interference with RUNX1/ETO Leukemogenic Function by Cell-Penetrating Peptides Targeting the NHR2 Oligomerization Domain

    Directory of Open Access Journals (Sweden)

    Yvonne Bartel

    2013-01-01

    Full Text Available The leukemia-associated fusion protein RUNX1/ETO is generated by the chromosomal translocation t(8;21 which appears in about 12% of all de novo acute myeloid leukemias (AMLs. Essential for the oncogenic potential of RUNX1/ETO is the oligomerization of the chimeric fusion protein through the nervy homology region 2 (NHR2 within ETO. In previous studies, we have shown that the intracellular expression of peptides containing the NHR2 domain inhibits RUNX1/ETO oligomerization, thereby preventing cell proliferation and inducing differentiation of RUNX1/ETO transformed cells. Here, we show that introduction of a recombinant TAT-NHR2 fusion polypeptide into the RUNX1/ETO growth-dependent myeloid cell line Kasumi-1 results in decreased cell proliferation and increased numbers of apoptotic cells. This effect was highly specific and mediated by binding the TAT-NHR2 peptide to ETO sequences, as TAT-polypeptides containing the oligomerization domain of BCR did not affect cell proliferation or apoptosis in Kasumi-1 cells. Thus, the selective interference with NHR2-mediated oligomerization by peptides represents a challenging but promising strategy for the inhibition of the leukemogenic potential of RUNX1/ETO in t(8;21-positive leukemia.

  17. Association of Nucleotide-binding Oligomerization Domain Receptors with Peptic Ulcer and Gastric Cancer.

    Science.gov (United States)

    Mohammadian Amiri, Rajeeh; Tehrani, Mohsen; Taghizadeh, Shirin; Shokri-Shirvani, Javad; Fakheri, Hafez; Ajami, Abolghasem

    2016-10-01

    Host innate immunity can affect the clinical outcomes of Helicobacter pylori infection, including gastritis, gastric ulcer, gastric adenocarcinoma, and MALT lymphoma. Nucleotide binding oligomerization domain (NOD)-1 and -2 are two molecules of innate immunity which are involved in the host defense against H. pylori. This study aimed to evaluate the effect of the expression level of NOD1 and NOD2 on the susceptibility to gastric cancer as well as peptic ulcer in individuals with H. pylori infection. The gene expression levels of these molecules were compared in three groups of non-ulcer dyspepsia (NUD) as a control group (n=52); peptic ulcer disease (PUD), (n=53); and gastric cancer (GC), (n=39). Relative expression levels of NOD1 in patients with GC were higher than those of NUD and PUD (p<0.001 and P<0.001, respectively). Similarly in case of NOD1, PUD group showed higher level of expression than NUD group (p<0.01). However, there was no significant difference between H. pylori -positive and -negative patients in NUD, PUD, or GC groups. Moreover, the expression levels of NOD2 showed no significant difference among NUD, PUD, or GC groups, while among H. pylori-positive patients, it was higher in GC group than NUD  and PUD groups (p<0.05 and p<0.01, respectively). In addition, positive correlation coefficients were attained between NOD1 and NOD2 expressions in patients with NUD (R2 Linear=0.349, p<0.001), PUD (R2 Linear=0.695, p<0.001), and GC (R2 Linear=0.385, p<0.001). Collectively, the results suggest that the chronic activation of NOD1 and NOD2 receptors might play a role in the development of gastric cancer.

  18. Supplementary Material for: A new mode of SAM domain mediated oligomerization observed in the CASKIN2 neuronal scaffolding protein

    KAUST Repository

    Smirnova, Ekaterina; Kwan, Jamie; Siu, Ryan; Gao, Xin; Zoidl, Georg; Demeler, Borries; Saridakis, Vivian; Donaldson, Logan

    2016-01-01

    Abstract Background CASKIN2 is a homolog of CASKIN1, a scaffolding protein that participates in a signaling network with CASK (calcium/calmodulin-dependent serine kinase). Despite a high level of homology between CASKIN2 and CASKIN1, CASKIN2 cannot bind CASK due to the absence of a CASK Interaction Domain and consequently, may have evolved undiscovered structural and functional distinctions. Results We demonstrate that the crystal structure of the Sterile Alpha Motif (SAM) domain tandem (SAM1-SAM2) oligomer from CASKIN2 is different than CASKIN1, with the minimal repeating unit being a dimer, rather than a monomer. Analytical ultracentrifugation sedimentation velocity methods revealed differences in monomer/dimer equilibria across a range of concentrations and ionic strengths for the wild type CASKIN2 SAM tandem and a structure-directed double mutant that could not oligomerize. Further distinguishing CASKIN2 from CASKIN1, EGFP-tagged SAM tandem proteins expressed in Neuro2a cells produced punctae that were distinct both in shape and size. Conclusions This study illustrates a new way in which neuronal SAM domains can assemble into large macromolecular assemblies that might concentrate and amplify synaptic responses.

  19. Design of a minimal protein oligomerization domain by a structural approach.

    Science.gov (United States)

    Burkhard, P; Meier, M; Lustig, A

    2000-12-01

    Because of the simplicity and regularity of the alpha-helical coiled coil relative to other structural motifs, it can be conveniently used to clarify the molecular interactions responsible for protein folding and stability. Here we describe the de novo design and characterization of a two heptad-repeat peptide stabilized by a complex network of inter- and intrahelical salt bridges. Circular dichroism spectroscopy and analytical ultracentrifugation show that this peptide is highly alpha-helical and 100% dimeric tinder physiological buffer conditions. Interestingly, the peptide was shown to switch its oligomerization state from a dimer to a trimer upon increasing ionic strength. The correctness of the rational design principles used here is supported by details of the atomic structure of the peptide deduced from X-ray crystallography. The structure of the peptide shows that it is not a molten globule but assumes a unique, native-like conformation. This de novo peptide thus represents an attractive model system for the design of a molecular recognition system.

  20. A new mode of SAM domain mediated oligomerization observed in the CASKIN2 neuronal scaffolding protein

    KAUST Repository

    Smirnova, Ekaterina; Kwan, Jamie J.; Siu, Ryan; Gao, Xin; Zoidl, Georg; Demeler, Borries; Saridakis, Vivian; Donaldson, Logan W.

    2016-01-01

    Background: CASKIN2 is a homolog of CASKIN1, a scaffolding protein that participates in a signaling network with CASK (calcium/calmodulin-dependent serine kinase). Despite a high level of homology between CASKIN2 and CASKIN1, CASKIN2 cannot bind CASK due to the absence of a CASK Interaction Domain and consequently, may have evolved undiscovered structural and functional distinctions.

  1. A new mode of SAM domain mediated oligomerization observed in the CASKIN2 neuronal scaffolding protein

    KAUST Repository

    Smirnova, Ekaterina

    2016-08-22

    Background: CASKIN2 is a homolog of CASKIN1, a scaffolding protein that participates in a signaling network with CASK (calcium/calmodulin-dependent serine kinase). Despite a high level of homology between CASKIN2 and CASKIN1, CASKIN2 cannot bind CASK due to the absence of a CASK Interaction Domain and consequently, may have evolved undiscovered structural and functional distinctions.

  2. Nucleotide-Binding Oligomerization Domain-1 and -2 Play No Role in Controlling Brucella abortus Infection in Mice

    Directory of Open Access Journals (Sweden)

    Fernanda S. Oliveira

    2012-01-01

    Full Text Available Nucleotide-binding oligomerization domain proteins (NODs are modular cytoplasmic proteins implicated in the recognition of peptidoglycan-derived molecules. Further, several in vivo studies have demonstrated a role for Nod1 and Nod2 in host defense against bacterial pathogens. Here, we demonstrated that macrophages from NOD1-, NOD2-, and Rip2-deficient mice produced lower levels of TNF-α following infection with live Brucella abortus compared to wild-type mice. Similar reduction on cytokine synthesis was not observed for IL-12 and IL-6. However, NOD1, NOD2, and Rip2 knockout mice were no more susceptible to infection with virulent B. abortus than wild-type mice. Additionally, spleen cells from NOD1-, NOD2-, and Rip2-deficient mice showed unaltered production of IFN-γ compared to C57BL/6 mice. Taken together, this study demonstrates that NOD1, NOD2 and Rip2 are dispensable for the control of B. abortus during in vivo infection.

  3. Role of Nucleotide-Binding Oligomerization Domain-Containing (NOD 2 in Host Defense during Pneumococcal Pneumonia.

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    Tijmen J Hommes

    Full Text Available Streptococcus (S. pneumoniae is the most common causative pathogen in community-acquired pneumonia. Nucleotide-binding oligomerization domain-containing (NOD 2 is a pattern recognition receptor located in the cytosol of myeloid cells that is able to detect peptidoglycan fragments of S. pneumoniae. We here aimed to investigate the role of NOD2 in the host response during pneumococcal pneumonia. Phagocytosis of S. pneumoniae was studied in NOD2 deficient (Nod2-/- and wild-type (Wt alveolar macrophages and neutrophils in vitro. In subsequent in vivo experiments Nod2-/- and Wt mice were inoculated with serotype 2 S. pneumoniae (D39, an isogenic capsule locus deletion mutant (D39Δcps or serotype 3 S. pneumoniae (6303 via the airways, and bacterial growth and dissemination and the lung inflammatory response were evaluated. Nod2-/- alveolar macrophages and blood neutrophils displayed a reduced capacity to internalize pneumococci in vitro. During pneumonia caused by S. pneumoniae D39 Nod2-/- mice were indistinguishable from Wt mice with regard to bacterial loads in lungs and distant organs, lung pathology and neutrophil recruitment. While Nod2-/- and Wt mice also had similar bacterial loads after infection with the more virulent S. pneumoniae 6303 strain, Nod2-/- mice displayed a reduced bacterial clearance of the normally avirulent unencapsulated D39Δcps strain. These results suggest that NOD2 does not contribute to host defense during pneumococcal pneumonia and that the pneumococcal capsule impairs recognition of S. pneumoniae by NOD2.

  4. Critical role of nucleotide-binding oligomerization domain-like receptor 3 in vascular repair

    Energy Technology Data Exchange (ETDEWEB)

    Schlaweck, Sebastian; Zimmer, Sebastian; Struck, Rafael [Department of Medicine/Cardiology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn (Germany); Bartok, Eva [Institute for Clinical Chemistry and Clinical Pharmacology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn (Germany); Werner, Nikos [Department of Medicine/Cardiology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn (Germany); Bauernfeind, Franz [Institute for Clinical Chemistry and Clinical Pharmacology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn (Germany); Latz, Eicke [Institute of Innate Immunity, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn (Germany); Nickenig, Georg [Department of Medicine/Cardiology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn (Germany); Hornung, Veit [Institute for Clinical Chemistry and Clinical Pharmacology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn (Germany); Ghanem, Alexander, E-mail: ghanem@uni-bonn.de [Department of Medicine/Cardiology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn (Germany)

    2011-08-05

    Highlights: {yields} NLRP3 is not required for systemic cardiovascular function in healthy mice. {yields} NLRP3 deficiency itself does not affect the functional cardiovascular phenotype and that it does not alter peripheral differential blood counts. {yields} NLRP3 is critical in neointima formation following vascular injury. -- Abstract: Vascular remodeling characterized by hyperproliferative neointima formation is an unfavorable repair process that is triggered by vascular damage. This process is characterized by an increased local inflammatory and proliferative response that critically involves the pro-inflammatory cytokine interleukin-1{beta} (IL-1{beta}). IL-1{beta} is expressed and cytosolically retained as a procytokine that requires additional processing prior to exerting its pro-inflammatory function. Maturation and release of pro IL-1{beta} is governed by a cytosolic protein scaffold that is known as the inflammasome. Here we show that NLRP3 (NOD-like receptor family, pryin domain containing 3), an important activating component of the inflammasome, is involved in neointima formation after vascular injury. NLRP3 deficiency itself does not affect the functional cardiovascular phenotype and does not alter peripheral differential blood counts. However, neointima development following wire injury of the carotid artery was significantly decreased in NLRP3-deficient mice as compared to wild-type controls. In all, NLRP3 plays a non-redundant role in vascular damage mediated neointima formation. Our data establish NLRP3 as a key player in the response to vascular damage, which could open new avenues to therapeutic intervention.

  5. Critical role of nucleotide-binding oligomerization domain-like receptor 3 in vascular repair

    International Nuclear Information System (INIS)

    Schlaweck, Sebastian; Zimmer, Sebastian; Struck, Rafael; Bartok, Eva; Werner, Nikos; Bauernfeind, Franz; Latz, Eicke; Nickenig, Georg; Hornung, Veit; Ghanem, Alexander

    2011-01-01

    Highlights: → NLRP3 is not required for systemic cardiovascular function in healthy mice. → NLRP3 deficiency itself does not affect the functional cardiovascular phenotype and that it does not alter peripheral differential blood counts. → NLRP3 is critical in neointima formation following vascular injury. -- Abstract: Vascular remodeling characterized by hyperproliferative neointima formation is an unfavorable repair process that is triggered by vascular damage. This process is characterized by an increased local inflammatory and proliferative response that critically involves the pro-inflammatory cytokine interleukin-1β (IL-1β). IL-1β is expressed and cytosolically retained as a procytokine that requires additional processing prior to exerting its pro-inflammatory function. Maturation and release of pro IL-1β is governed by a cytosolic protein scaffold that is known as the inflammasome. Here we show that NLRP3 (NOD-like receptor family, pryin domain containing 3), an important activating component of the inflammasome, is involved in neointima formation after vascular injury. NLRP3 deficiency itself does not affect the functional cardiovascular phenotype and does not alter peripheral differential blood counts. However, neointima development following wire injury of the carotid artery was significantly decreased in NLRP3-deficient mice as compared to wild-type controls. In all, NLRP3 plays a non-redundant role in vascular damage mediated neointima formation. Our data establish NLRP3 as a key player in the response to vascular damage, which could open new avenues to therapeutic intervention.

  6. Solution structure of the isolated Pelle death domain.

    Science.gov (United States)

    Moncrieffe, Martin C; Stott, Katherine M; Gay, Nicholas J

    2005-07-18

    The interaction between the death domains (DDs) of Tube and the protein kinase Pelle is an important component of the Toll pathway. Published crystallographic data suggests that the Pelle-Tube DD interface is plastic and implies that in addition to the two predominant Pelle-Tube interfaces, a third interaction is possible. We present the NMR solution structure of the isolated death domain of Pelle and a study of the interaction between the DDs of Pelle and Tube. Our data suggests the solution structure of the isolated Pelle DD is similar to that of Pelle DD in complex with Tube. Additionally, they suggest that the plasticity observed in the crystal structure may not be relevant in the functioning death domain complex.

  7. Nucleotide-oligomerizing domain-1 (NOD1) receptor activation induces pro-inflammatory responses and autophagy in human alveolar macrophages.

    Science.gov (United States)

    Juárez, Esmeralda; Carranza, Claudia; Hernández-Sánchez, Fernando; Loyola, Elva; Escobedo, Dante; León-Contreras, Juan Carlos; Hernández-Pando, Rogelio; Torres, Martha; Sada, Eduardo

    2014-09-25

    Nucleotide-binding oligomerizing domain-1 (NOD1) is a cytoplasmic receptor involved in recognizing bacterial peptidoglycan fragments that localize to the cytosol. NOD1 activation triggers inflammation, antimicrobial mechanisms and autophagy in both epithelial cells and murine macrophages. NOD1 mediates intracellular pathogen clearance in the lungs of mice; however, little is known about NOD1's role in human alveolar macrophages (AMs) or its involvement in Mycobacterium tuberculosis (Mtb) infection. AMs, monocytes (MNs), and monocyte-derived macrophages (MDMs) from healthy subjects were assayed for NOD1 expression. Cells were stimulated with the NOD1 ligand Tri-DAP and cytokine production and autophagy were assessed. Cells were infected with Mtb and treated with Tri-DAP post-infection. CFUs counting determined growth control, and autophagy protein recruitment to pathogen localization sites was analyzed by immunoelectron microscopy. NOD1 was expressed in AMs, MDMs and to a lesser extent MNs. Tri-DAP stimulation induced NOD1 up-regulation and a significant production of IL1β, IL6, IL8, and TNFα in AMs and MDMs; however, the level of NOD1-dependent response in MNs was limited. Autophagy activity determined by expression of proteins Atg9, LC3, IRGM and p62 degradation was induced in a NOD1-dependent manner in AMs and MDMs but not in MNs. Infected AMs could be activated by stimulation with Tri-DAP to control the intracellular growth of Mtb. In addition, recruitment of NOD1 and the autophagy proteins IRGM and LC3 to the Mtb localization site was observed in infected AMs after treatment with Tri-DAP. NOD1 is involved in AM and MDM innate responses, which include proinflammatory cytokines and autophagy, with potential implications in the killing of Mtb in humans.

  8. Activation of nucleotide oligomerization domain 2 (NOD2 by human cytomegalovirus initiates innate immune responses and restricts virus replication.

    Directory of Open Access Journals (Sweden)

    Arun Kapoor

    Full Text Available Nucleotide-binding oligomerization domain 2 (NOD2 is an important innate immune sensor of bacterial pathogens. Its induction results in activation of the classic NF-κB pathway and alternative pathways including type I IFN and autophagy. Although the importance of NOD2 in recognizing RNA viruses has recently been identified, its role in sensing DNA viruses has not been studied. We report that infection with human cytomegalovirus (HCMV results in significant induction of NOD2 expression, beginning as early as 2 hours post infection and increasing steadily 24 hours post infection and afterwards. Infection with human herpesvirus 1 and 2 does not induce NOD2 expression. While the HCMV-encoded glycoprotein B is not required for NOD2 induction, a replication competent virion is necessary. Lentivirus-based NOD2 knockdown in human foreskin fibroblasts (HFFs and U373 glioma cells leads to enhanced HCMV replication along with decreased levels of interferon beta (IFN-β and the pro-inflammatory cytokine, IL8. NOD2 induction in HCMV-infected cells activates downstream NF-κB and interferon pathways supported by reduced nuclear localization of NF-κB and pIRF3 in NOD2 knockdown HFFs. Stable overexpression of NOD2 in HFFs restricts HCMV replication in association with increased levels of IFN-β and IL8. Similarly, transient overexpression of NOD2 in U373 cells or its downstream kinase, RIPK2, results in decreased HCMV replication and enhanced cytokine responses. However, overexpression of a mutant NOD2, 3020insC, associated with severe Crohn's disease, results in enhanced HCMV replication and decreased levels of IFN-β in U373 cells. These results show for the first time that NOD2 plays a significant role in HCMV replication and may provide a model for studies of HCMV recognition by the host cell and HCMV colitis in Crohn's disease.

  9. Structure-based design of a disulfide-linked oligomeric form of the simian virus 40 (SV40) large T antigen DNA-binding domain

    International Nuclear Information System (INIS)

    Meinke, Gretchen; Phelan, Paul; Fradet-Turcotte, Amélie; Archambault, Jacques; Bullock, Peter A.

    2011-01-01

    With the aim of forming the ‘lock-washer’ conformation of the origin-binding domain of SV40 large T antigen in solution, using structure-based analysis an intermolecular disulfide bridge was engineered into the origin-binding domain to generate higher order oligomers in solution. The 1.7 Å resolution structure shows that the mutant forms a spiral in the crystal and has the de novo disulfide bond at the protein interface, although structural rearrangements at the interface are observed relative to the wild type. The modular multifunctional protein large T antigen (T-ag) from simian virus 40 orchestrates many of the events needed for replication of the viral double-stranded DNA genome. This protein assembles into single and double hexamers on specific DNA sequences located at the origin of replication. This complicated process begins when the origin-binding domain of large T antigen (T-ag ODB) binds the GAGGC sequences in the central region (site II) of the viral origin of replication. While many of the functions of purified T-ag OBD can be studied in isolation, it is primarily monomeric in solution and cannot assemble into hexamers. To overcome this limitation, the possibility of engineering intermolecular disulfide bonds in the origin-binding domain which could oligomerize in solution was investigated. A recent crystal structure of the wild-type T-ag OBD showed that this domain forms a left-handed spiral in the crystal with six subunits per turn. Therefore, we analyzed the protein interface of this structure and identified two residues that could potentially support an intermolecular disulfide bond if changed to cysteines. SDS–PAGE analysis established that the mutant T-ag OBD formed higher oligomeric products in a redox-dependent manner. In addition, the 1.7 Å resolution crystal structure of the engineered disulfide-linked T-ag OBD is reported, which establishes that oligomerization took place in the expected manner

  10. The death effector domains of caspase-8 induce terminal differentiation.

    Directory of Open Access Journals (Sweden)

    Ainhoa Mielgo

    2009-11-01

    Full Text Available The differentiation and senescence programs of metazoans play key roles in regulating normal development and preventing aberrant cell proliferation, such as cancer. These programs are intimately associated with both the mitotic and apoptotic pathways. Caspase-8 is an apical apoptotic initiator that has recently been appreciated to coordinate non-apoptotic roles in the cell. Most of these functions are attributed to the catalytic domain, however, the amino-terminal death effector domains (DEDs, which belong to the death domain superfamily of proteins, can also play key roles during development. Here we describe a novel role for caspase-8 DEDs in regulating cell differentiation and senescence. Caspase-8 DEDs accumulate during terminal differentiation and senescence of epithelial, endothelial and myeloid cells; genetic deletion or shRNA suppression of caspase-8 disrupts cell differentiation, while re-expression of DEDs rescues this phenotype. Among caspase-8 deficient neuroblastoma cells, DED expression attenuated tumor growth in vivo and proliferation in vitro via disruption of mitosis and cytokinesis, resulting in upregulation of p53 and induction of differentiation markers. These events occur independent of caspase-8 catalytic activity, but require a critical lysine (K156 in a microtubule-binding motif in the second DED domain. The results demonstrate a new function for the DEDs of caspase-8, and describe an unexpected mechanism that contributes to cell differentiation and senescence.

  11. Carbon Domains on MoS2/TiO2 System via Catalytic Acetylene Oligomerization: Synthesis, Structure, and Surface Properties

    Directory of Open Access Journals (Sweden)

    Sara Cravanzola

    2017-11-01

    Full Text Available Carbon domains have been obtained at the surface of a MoS2/TiO2 (Evonik, P25 system via oligomerization and cyclotrimerization reactions involved in the interaction of the photoactive material with acetylene. Firstly, MoS2 nanosheets have been synthesized at the surface of TiO2, via sulfidation of a molybdenum oxide precursor with H2S (bottom-up method. Secondly, the morphology and the structure, the optical and the vibrational properties of the obtained materials, for each step of the synthesis procedure, have been investigated by microscopy and spectroscopy methods. In particular, transmission electron microscopy images provide a simple tool to highlight the effectiveness of the sulfidation process, thus showing 1L, 2L, and stacked MoS2 nanosheets anchored to the surface of TiO2 nanoparticles. Lastly, in-situ FTIR spectroscopy investigation gives insights into the nature of the oligomerized species, showing that the formation of both polyenic and aromatic systems can be taken into account, being their formation promoted by both Ti and Mo catalytic sites. This finding gives an opportunity for the assembly of extended polyenic, polyaromatic, or mixed domains firmly attached at the surface of photoactive materials. The presented approach, somehow different from the carbon adding or doping processes of TiO2, is of potential interest for the advanced green chemistry and energy conversion/transport applications.

  12. Implication of the oligomeric state of the N-terminal PTX3 domain in cumulus matrix assembly.

    Science.gov (United States)

    Ievoli, Elena; Lindstedt, Ragnar; Inforzato, Antonio; Camaioni, Antonella; Palone, Francesca; Day, Anthony J; Mantovani, Alberto; Salvatori, Giovanni; Salustri, Antonietta

    2011-06-01

    Pentraxin 3 (PTX3) plays a key role in the formation of the hyaluronan-rich matrix of the cumulus oophorus surrounding ovulated eggs that is required for successful fertilization and female fertility. PTX3 is a multimeric protein consisting of eight identical protomers held together by a combination of non-covalent interactions and disulfide bonds. Recent findings suggest that the oligomeric status of PTX3 is important for stabilizing the cumulus matrix. Because the role of PTX3 in the cumulus resides in the unique N-terminal sequence of the protomer, we investigated further this issue by testing the ability of distinct Cys/Ser mutants of recombinant N-terminal region of PTX3 (N(_)PTX3) with different oligomeric arrangement to promote in vitro normal expansion in cumuli from Ptx3-null mice. Here we report that the dimer of the N(_)PTX3 is unable to rescue cumulus matrix organization, and that the tetrameric assembly of the protein is the minimal oligomeric state required for accomplishing this function. We have previously demonstrated that PTX3 binds to HCs of IαI and TSG-6, which are essential for cumulus matrix formation and able to interact with hyaluronan. Interestingly, here we show by solid-phase binding experiments that the dimer of the N(_)PTX3 retains the ability to bind to both IαI and TSG-6, suggesting that the octameric structure of PTX3 provides multiple binding sites for each of these ligands. These findings support the hypothesis that PTX3 contributes to cumulus matrix organization by cross-linking HA polymers through interactions with multiple HCs of IαI and/or TSG-6. The N-terminal PTX3 tetrameric oligomerization was recently reported to be also required for recognition and inhibition of FGF2. Given that this growth factor has been detected in the mammalian preovulatory follicle, we wondered whether FGF2 negatively influences cumulus expansion and PTX3 may also serve in vivo to antagonize its activity. We found that a molar excess of FGF2, above

  13. One motif to bind them: A small-XXX-small motif affects transmembrane domain 1 oligomerization, function, localization, and cross-talk between two yeast GPCRs.

    Science.gov (United States)

    Lock, Antonia; Forfar, Rachel; Weston, Cathryn; Bowsher, Leo; Upton, Graham J G; Reynolds, Christopher A; Ladds, Graham; Dixon, Ann M

    2014-12-01

    G protein-coupled receptors (GPCRs) are the largest family of cell-surface receptors in mammals and facilitate a range of physiological responses triggered by a variety of ligands. GPCRs were thought to function as monomers, however it is now accepted that GPCR homo- and hetero-oligomers also exist and influence receptor properties. The Schizosaccharomyces pombe GPCR Mam2 is a pheromone-sensing receptor involved in mating and has previously been shown to form oligomers in vivo. The first transmembrane domain (TMD) of Mam2 contains a small-XXX-small motif, overrepresented in membrane proteins and well-known for promoting helix-helix interactions. An ortholog of Mam2 in Saccharomyces cerevisiae, Ste2, contains an analogous small-XXX-small motif which has been shown to contribute to receptor homo-oligomerization, localization and function. Here we have used experimental and computational techniques to characterize the role of the small-XXX-small motif in function and assembly of Mam2 for the first time. We find that disruption of the motif via mutagenesis leads to reduction of Mam2 TMD1 homo-oligomerization and pheromone-responsive cellular signaling of the full-length protein. It also impairs correct targeting to the plasma membrane. Mutation of the analogous motif in Ste2 yielded similar results, suggesting a conserved mechanism for assembly. Using co-expression of the two fungal receptors in conjunction with computational models, we demonstrate a functional change in G protein specificity and propose that this is brought about through hetero-dimeric interactions of Mam2 with Ste2 via the complementary small-XXX-small motifs. This highlights the potential of these motifs to affect a range of properties that can be investigated in other GPCRs. Copyright © 2014. Published by Elsevier B.V.

  14. Oligomeric structure and chaperone-like activity of Drosophila melanogaster mitochondrial small heat shock protein Hsp22 and arginine mutants in the alpha-crystallin domain.

    Science.gov (United States)

    Dabbaghizadeh, Afrooz; Finet, Stéphanie; Morrow, Genevieve; Moutaoufik, Mohamed Taha; Tanguay, Robert M

    2017-07-01

    The structure and chaperone function of DmHsp22WT, a small Hsp of Drosophila melanogaster localized within mitochondria were examined. Mutations of conserved arginine mutants within the alpha-crystallin domain (ACD) domain (R105G, R109G, and R110G) were introduced, and their effects on oligomerization and chaperone function were assessed. Arginine to glycine mutations do not induce significant changes in tryptophan fluorescence, and the mutated proteins form oligomers that are of equal or smaller size than the wild-type protein. They all form oligomer with one single peak as determined by size exclusion chromatography. While all mutants demonstrate the same efficiency as the DmHsp22WT in a DTT-induced insulin aggregation assay, all are more efficient chaperones to prevent aggregation of malate dehydrogenase. Arginine mutants of DmHsp22 are efficient chaperones to retard aggregation of CS and Luc. In summary, this study shows that mutations of arginine to glycine in DmHsp22 ACD induce a number of structural changes, some of which differ from those described in mammalian sHsps. Interestingly, only the R110G-DmHsp22 mutant, and not the expected R109G equivalent to human R140-HspB1, R116-HspB4, and R120-HspB5, showed different structural properties compared with the DmHsp22WT.

  15. Structural and functional characterization of the recombinant death domain from death-associated protein kinase.

    Science.gov (United States)

    Dioletis, Evangelos; Dingley, Andrew J; Driscoll, Paul C

    2013-01-01

    Death-associated protein kinase (DAPk) is a calcium/calmodulin-regulated Ser/Thr-protein kinase that functions at an important point of integration for cell death signaling pathways. DAPk has a structurally unique multi-domain architecture, including a C-terminally positioned death domain (DD) that is a positive regulator of DAPk activity. In this study, recombinant DAPk-DD was observed to aggregate readily and could not be prepared in sufficient yield for structural analysis. However, DAPk-DD could be obtained as a soluble protein in the form of a translational fusion protein with the B1 domain of streptococcal protein G. In contrast to other DDs that adopt the canonical six amphipathic α-helices arranged in a compact fold, the DAPk-DD was found to possess surprisingly low regular secondary structure content and an absence of a stable globular fold, as determined by circular dichroism (CD), NMR spectroscopy and a temperature-dependent fluorescence assay. Furthermore, we measured the in vitro interaction between extracellular-regulated kinase-2 (ERK2) and various recombinant DAPk-DD constructs. Despite the low level of structural order, the recombinant DAPk-DD retained the ability to interact with ERK2 in a 1∶1 ratio with a K d in the low micromolar range. Only the full-length DAPk-DD could bind ERK2, indicating that the apparent 'D-motif' located in the putative sixth helix of DAPk-DD is not sufficient for ERK2 recognition. CD analysis revealed that binding of DAPk-DD to ERK2 is not accompanied by a significant change in secondary structure. Taken together our data argue that the DAPk-DD, when expressed in isolation, does not adopt a classical DD fold, yet in this state retains the capacity to interact with at least one of its binding partners. The lack of a stable globular structure for the DAPk-DD may reflect either that its folding would be supported by interactions absent in our experimental set-up, or a limitation in the structural bioinformatics

  16. Oligomerization process

    Science.gov (United States)

    Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

    1991-03-26

    A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled. 2 figures.

  17. Discovery of Nanomolar Desmuramylpeptide Agonists of the Innate Immune Receptor Nucleotide-Binding Oligomerization Domain-Containing Protein 2 (NOD2) Possessing Immunostimulatory Properties.

    Science.gov (United States)

    Gobec, Martina; Tomašič, Tihomir; Štimac, Adela; Frkanec, Ruža; Trontelj, Jurij; Anderluh, Marko; Mlinarič-Raščan, Irena; Jakopin, Žiga

    2018-04-12

    Muramyl dipeptide (MDP), a fragment of bacterial peptidoglycan, has long been known as the smallest fragment possessing adjuvant activity, on the basis of its agonistic action on the nucleotide-binding oligomerization domain-containing protein 2 (NOD2). There is a pressing need for novel adjuvants, and NOD2 agonists provide an untapped source of potential candidates. Here, we report the design, synthesis, and characterization of a series of novel acyl tripeptides. A pivotal structural element for molecular recognition by NOD2 has been identified, culminating in the discovery of compound 9, the most potent desmuramylpeptide NOD2 agonist to date. Compound 9 augmented pro-inflammatory cytokine release from human peripheral blood mononuclear cells in synergy with lipopolysaccharide. Furthermore, it was able to induce ovalbumin-specific IgG titers in a mouse model of adjuvancy. These findings provide deeper insights into the structural requirements of desmuramylpeptides for NOD2-activation and highlight the potential use of NOD2 agonists as adjuvants for vaccines.

  18. Fusion of the Mycobacterium tuberculosis antigen 85A to an oligomerization domain enhances its immunogenicity in both mice and non-human primates.

    Directory of Open Access Journals (Sweden)

    Alexandra J Spencer

    Full Text Available To prevent important infectious diseases such as tuberculosis, malaria and HIV, vaccines inducing greater T cell responses are required. In this study, we investigated whether fusion of the M. tuberculosis antigen 85A to recently described adjuvant IMX313, a hybrid avian C4bp oligomerization domain, could increase T cell responses in pre-clinical vaccine model species. In mice, the fused antigen 85A showed consistent increases in CD4(+ and CD8(+ T cell responses after DNA and MVA vaccination. In rhesus macaques, higher IFN-γ responses were observed in animals vaccinated with MVA-Ag85A IMX313 after both primary and secondary immunizations. In both animal models, fusion to IMX313 induced a quantitative enhancement in the response without altering its quality: multifunctional cytokines were uniformly increased and differentiation into effector and memory T cell subsets was augmented rather than skewed. An extensive in vivo characterization suggests that IMX313 improves the initiation of immune responses as an increase in antigen 85A specific cells was observed as early as day 3 after vaccination. This report demonstrates that antigen multimerization using IMX313 is a simple and effective cross-species method to improve vaccine immunogenicity with potentially broad applicability.

  19. The TIR domain of TIR-NB-LRR resistance proteins is a signaling domain involved in cell death induction.

    Science.gov (United States)

    Swiderski, Michal R; Birker, Doris; Jones, Jonathan D G

    2009-02-01

    In plants, the TIR (toll interleukin 1 receptor) domain is found almost exclusively in nucleotide-binding (NB) leucine-rich repeat resistance proteins and their truncated homologs, and has been proposed to play a signaling role during resistance responses mediated by TIR containing R proteins. Transient expression in Nicotiana benthamiana leaves of "TIR + 80", the RPS4 truncation without the NB-ARC domain, leads to EDS1-, SGT1-, and HSP90-dependent cell death. Transgenic Arabidopsis plants expressing the RPS4 TIR+80 from either dexamethasone or estradiol-inducible promoters display inducer-dependent cell death. Cell death is also elicited by transient expression of similarly truncated constructs from two other R proteins, RPP1A and At4g19530, but is not elicited by similar constructs representing RPP2A and RPP2B proteins. Site-directed mutagenesis of the RPS4 TIR domain identified many loss-of-function mutations but also revealed several gain-of function substitutions. Lack of cell death induction by the E160A substitution suggests that amino acids outside of the TIR domain contribute to cell death signaling in addition to the TIR domain itself. This is consistent with previous observations that the TIR domain itself is insufficient to induce cell death upon transient expression.

  20. Molecular cloning and functional analysis of nucleotide-binding oligomerization domain-containing protein 1 in rainbow trout, Oncorhynchus mykiss.

    Science.gov (United States)

    Jang, Ju Hye; Kim, Hyun; Kim, Yu Jin; Cho, Ju Hyun

    2016-04-01

    NOD1 has important roles in innate immunity as sensor of microbial components derived from bacterial peptidoglycan. In this study, we identified genes encoding components of the NOD1 signaling pathway, including NOD1 (OmNOD1) and RIP2 (OmRIP2) from rainbow trout, Oncorhynchus mykiss, and investigated whether OmNOD1 has immunomodulating activity in a rainbow trout hepatoma cell line RTH-149 treated with NOD1-specific ligand (iE-DAP). The deduced amino acid sequence of OmNOD1 contained conserved CARD, NOD and LRR domains. Loss-of-function and gain-of-function experiments indicated that OmNOD1 is involved in the expression of pro-inflammatory cytokines. Silencing of OmNOD1 in RTH-149 cells treated with iE-DAP decreased the expression of IL-1β, IL-6, IL-8 and TNF-α. Conversely, overexpression of OmNOD1 resulted in up-regulation of IL-1β, IL-6, IL-8 and TNF-α expression. In addition, RIP2 inhibitor (gefitinib) significantly decreased the expression of these pro-inflammatory cytokines induced by iE-DAP in RTH-149 cells. These findings highlight the important role of NOD1 signaling pathway in fish in eliciting innate immune response. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Invasive Streptococcus mutans induces inflammatory cytokine production in human aortic endothelial cells via regulation of intracellular toll-like receptor 2 and nucleotide-binding oligomerization domain 2.

    Science.gov (United States)

    Nagata, E; Oho, T

    2017-04-01

    Streptococcus mutans, the primary etiologic agent of dental caries, can gain access to the bloodstream and has been associated with cardiovascular disease. However, the roles of S. mutans in inflammation in cardiovascular disease remain unclear. The aim of this study was to examine cytokine production induced by S. mutans in human aortic endothelial cells (HAECs) and to evaluate the participation of toll-like receptors (TLRs) and cytoplasmic nucleotide-binding oligomerization domain (NOD) -like receptors in HAECs. Cytokine production by HAECs was determined using enzyme-linked immunosorbent assays, and the expression of TLRs and NOD-like receptors was evaluated by real-time polymerase chain reaction, flow cytometry and immunocytochemistry. The involvement of TLR2 and NOD2 in cytokine production by invaded HAECs was examined using RNA interference. The invasion efficiencies of S. mutans strains were evaluated by means of antibiotic protection assays. Five of six strains of S. mutans of various serotypes induced interleukin-6, interleukin-8 and monocyte chemoattractant protein-1 production by HAECs. All S. mutans strains upregulated TLR2 and NOD2 mRNA levels in HAECs. Streptococcus mutans Xc upregulated the intracellular TLR2 and NOD2 protein levels in HAECs. Silencing of the TLR2 and NOD2 genes in HAECs invaded by S. mutans Xc led to a reduction in interleukin-6, interleukin-8 and monocyte chemoattractant protein-1 production. Cytokine production induced by invasive S. mutans via intracellular TLR2 and NOD2 in HAECs may be associated with inflammation in cardiovascular disease. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Recognition of ERK MAP kinase by PEA-15 reveals a common docking site within the death domain and death effector domain

    OpenAIRE

    Hill, Justine M.; Vaidyanathan, Hema; Ramos, Joe W.; Ginsberg, Mark H.; Werner, Milton H.

    2002-01-01

    PEA-15 is a multifunctional protein that modulates signaling pathways which control cell proliferation and cell death. In particular, PEA-15 regulates the actions of the ERK MAP kinase cascade by binding to ERK and altering its subcellular localization. The three-dimensional structure of PEA-15 has been determined using NMR spectroscopy and its interaction with ERK defined by characterization of mutants that modulate ERK function. PEA-15 is composed of an N-terminal death effector domain (DED...

  3. Protein phosphatase 2a (PP2A binds within the oligomerization domain of striatin and regulates the phosphorylation and activation of the mammalian Ste20-Like kinase Mst3

    Directory of Open Access Journals (Sweden)

    Jones Candace A

    2011-10-01

    Full Text Available Abstract Background Striatin, a putative protein phosphatase 2A (PP2A B-type regulatory subunit, is a multi-domain scaffolding protein that has recently been linked to several diseases including cerebral cavernous malformation (CCM, which causes symptoms ranging from headaches to stroke. Striatin association with the PP2A A/C (structural subunit/catalytic subunit heterodimer alters PP2A substrate specificity, but targets and roles of striatin-associated PP2A are not known. In addition to binding the PP2A A/C heterodimer to form a PP2A holoenzyme, striatin associates with cerebral cavernous malformation 3 (CCM3 protein, the mammalian Mps one binder (MOB homolog, Mob3/phocein, the mammalian sterile 20-like (Mst kinases, Mst3, Mst4 and STK25, and several other proteins to form a large signaling complex. Little is known about the molecular architecture of the striatin complex and the regulation of these sterile 20-like kinases. Results To help define the molecular organization of striatin complexes and to determine whether Mst3 might be negatively regulated by striatin-associated PP2A, a structure-function analysis of striatin was performed. Two distinct regions of striatin are capable of stably binding directly or indirectly to Mob3--one N-terminal, including the coiled-coil domain, and another more C-terminal, including the WD-repeat domain. In addition, striatin residues 191-344 contain determinants necessary for efficient association of Mst3, Mst4, and CCM3. PP2A associates with the coiled-coil domain of striatin, but unlike Mob3 and Mst3, its binding appears to require striatin oligomerization. Deletion of the caveolin-binding domain on striatin abolishes striatin family oligomerization and PP2A binding. Point mutations in striatin that disrupt PP2A association cause hyperphosphorylation and activation of striatin-associated Mst3. Conclusions Striatin orchestrates the regulation of Mst3 by PP2A. It binds Mst3 likely as a dimer with CCM3 via

  4. A S52P mutation in the 'α-crystallin domain' of Mycobacterium leprae HSP18 reduces its oligomeric size and chaperone function.

    Science.gov (United States)

    Nandi, Sandip K; Rehna, Elengikal A A; Panda, Alok K; Shiburaj, Sugathan; Dharmalingam, Kuppamuthu; Biswas, Ashis

    2013-12-01

    Mycobacterium leprae HSP18 is a small heat shock protein (sHSP). It is a major immunodominant antigen of M. leprae pathogen. Previously, we have reported the existence of two M. leprae HSP18 variants in various leprotic patients. One of the variants has serine at position 52, whereas the other one has proline at the same position. We have also reported that HSP18 having proline at position 52 (HSP18P(52)) is a nonameric protein and exhibits chaperone function. However, the structural and functional characterization of wild-type HSP18 having serine at position 52 (HSP18S(52)) is yet to be explored. Furthermore, the implications of the S52P mutation on the structure and chaperone function of HSP18 are not well understood. Therefore, we cloned and purified these two HSP18 variants. We found that HSP18S(52) is also a molecular chaperone and an oligomeric protein. Intrinsic tryptophan fluorescence and far-UV CD measurements revealed that the S52P mutation altered the tertiary and secondary structure of HSP18. This point mutation also reduced the oligomeric assembly and decreased the surface hydrophobicity of HSP18, as revealed by HPLC and 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid binding studies, respectively. Mutant protein was less stable against thermal and chemical denaturation and was more susceptible towards tryptic cleavage than wild-type HSP18. HSP18P(52) had lower chaperone function and was less effective in protecting thermal killing of Escherichia coli than HSP18S(52). Taken together, our data suggest that serine 52 is important for the larger oligomerization and chaperone function of HSP18. Because both variants differ in stability and function, they may have different roles in the survival of M. leprae in infected hosts. © 2013 FEBS.

  5. DCD – a novel plant specific domain in proteins involved in development and programmed cell death

    Directory of Open Access Journals (Sweden)

    Doerks Tobias

    2005-07-01

    Full Text Available Abstract Background Recognition of microbial pathogens by plants triggers the hypersensitive reaction, a common form of programmed cell death in plants. These dying cells generate signals that activate the plant immune system and alarm the neighboring cells as well as the whole plant to activate defense responses to limit the spread of the pathogen. The molecular mechanisms behind the hypersensitive reaction are largely unknown except for the recognition process of pathogens. We delineate the NRP-gene in soybean, which is specifically induced during this programmed cell death and contains a novel protein domain, which is commonly found in different plant proteins. Results The sequence analysis of the protein, encoded by the NRP-gene from soybean, led to the identification of a novel domain, which we named DCD, because it is found in plant proteins involved in development and cell death. The domain is shared by several proteins in the Arabidopsis and the rice genomes, which otherwise show a different protein architecture. Biological studies indicate a role of these proteins in phytohormone response, embryo development and programmed cell by pathogens or ozone. Conclusion It is tempting to speculate, that the DCD domain mediates signaling in plant development and programmed cell death and could thus be used to identify interacting proteins to gain further molecular insights into these processes.

  6. Birth and death of protein domains: A simple model of evolution explains power law behavior

    Directory of Open Access Journals (Sweden)

    Berezovskaya Faina S

    2002-10-01

    Full Text Available Abstract Background Power distributions appear in numerous biological, physical and other contexts, which appear to be fundamentally different. In biology, power laws have been claimed to describe the distributions of the connections of enzymes and metabolites in metabolic networks, the number of interactions partners of a given protein, the number of members in paralogous families, and other quantities. In network analysis, power laws imply evolution of the network with preferential attachment, i.e. a greater likelihood of nodes being added to pre-existing hubs. Exploration of different types of evolutionary models in an attempt to determine which of them lead to power law distributions has the potential of revealing non-trivial aspects of genome evolution. Results A simple model of evolution of the domain composition of proteomes was developed, with the following elementary processes: i domain birth (duplication with divergence, ii death (inactivation and/or deletion, and iii innovation (emergence from non-coding or non-globular sequences or acquisition via horizontal gene transfer. This formalism can be described as a birth, death and innovation model (BDIM. The formulas for equilibrium frequencies of domain families of different size and the total number of families at equilibrium are derived for a general BDIM. All asymptotics of equilibrium frequencies of domain families possible for the given type of models are found and their appearance depending on model parameters is investigated. It is proved that the power law asymptotics appears if, and only if, the model is balanced, i.e. domain duplication and deletion rates are asymptotically equal up to the second order. It is further proved that any power asymptotic with the degree not equal to -1 can appear only if the hypothesis of independence of the duplication/deletion rates on the size of a domain family is rejected. Specific cases of BDIMs, namely simple, linear, polynomial and rational

  7. The L-L oligomerization domain resides at the very N-terminus of the sendai virus L RNA polymerase protein

    International Nuclear Information System (INIS)

    Cevik, Bayram; Smallwood, Sherin; Moyer, Sue A.

    2003-01-01

    The Sendai virus RNA-dependent RNA polymerase is composed of the L and P proteins. We previously showed that the L protein gives intragenic complementation and forms an oligomer where the L-L interaction site mapped to the N-terminal half of the protein (S. Smallwood et al., 2002, Virology, 00, 000-000). We now show that L oligomerization does not depend on P protein and progressively smaller N-terminal fragments of L from amino acids (aa) 1-1146 through aa 1-174 all bind wild-type L. C-terminal truncations up to aa 424, which bind L, can complement the transcription defect in an L mutant altered at aa 379, although these L truncation mutants do not bind P. The fragment of L comprising aa 1-895, furthermore, acts as a dominant-negative mutant to inhibit transcription of wild-type L. N-terminal deletions of aa 1-189 and aa 1-734 have lost the ability to form the L-L complex as well as the L-P complex, although they still bind C protein. These data are consistent with the L-L interaction site residing in aa 1-174. Site-directed mutations in the N-terminal 347 aa, of L which abolish P binding, do not affect L-L complex formation, so while the L and P binding sites on L are overlapping they are mediated by different amino acids. The N-terminal portions of L with aa 1-424, aa 1-381, and to a lesser extent aa 1-174, can complement the transcription defect in an L mutant altered at aa 77-81, showing their L-L interaction is functional

  8. Molecular basis of coiled-coil oligomerization-state specificity.

    Science.gov (United States)

    Ciani, Barbara; Bjelic, Saša; Honnappa, Srinivas; Jawhari, Hatim; Jaussi, Rolf; Payapilly, Aishwarya; Jowitt, Thomas; Steinmetz, Michel O; Kammerer, Richard A

    2010-11-16

    Coiled coils are extensively and successfully used nowadays to rationally design multistranded structures for applications, including basic research, biotechnology, nanotechnology, materials science, and medicine. The wide range of applications as well as the important functions these structures play in almost all biological processes highlight the need for a detailed understanding of the factors that control coiled-coil folding and oligomerization. Here, we address the important and unresolved question why the presence of particular oligomerization-state determinants within a coiled coil does frequently not correlate with its topology. We found an unexpected, general link between coiled-coil oligomerization-state specificity and trigger sequences, elements that are indispensable for coiled-coil formation. By using the archetype coiled-coil domain of the yeast transcriptional activator GCN4 as a model system, we show that well-established trimer-specific oligomerization-state determinants switch the peptide's topology from a dimer to a trimer only when inserted into the trigger sequence. We successfully confirmed our results in two other, unrelated coiled-coil dimers, ATF1 and cortexillin-1. We furthermore show that multiple topology determinants can coexist in the same trigger sequence, revealing a delicate balance of the resulting oligomerization state by position-dependent forces. Our experimental results should significantly improve the prediction of the oligomerization state of coiled coils. They therefore should have major implications for the rational design of coiled coils and consequently many applications using these popular oligomerization domains.

  9. Identification of the Calmodulin-Binding Domains of Fas Death Receptor.

    Directory of Open Access Journals (Sweden)

    Bliss J Chang

    Full Text Available The extrinsic apoptotic pathway is initiated by binding of a Fas ligand to the ectodomain of the surface death receptor Fas protein. Subsequently, the intracellular death domain of Fas (FasDD and that of the Fas-associated protein (FADD interact to form the core of the death-inducing signaling complex (DISC, a crucial step for activation of caspases that induce cell death. Previous studies have shown that calmodulin (CaM is recruited into the DISC in cholangiocarcinoma cells and specifically interacts with FasDD to regulate the apoptotic/survival signaling pathway. Inhibition of CaM activity in DISC stimulates apoptosis significantly. We have recently shown that CaM forms a ternary complex with FasDD (2:1 CaM:FasDD. However, the molecular mechanism by which CaM binds to two distinct FasDD motifs is not fully understood. Here, we employed mass spectrometry, nuclear magnetic resonance (NMR, biophysical, and biochemical methods to identify the binding regions of FasDD and provide a molecular basis for the role of CaM in Fas-mediated apoptosis. Proteolytic digestion and mass spectrometry data revealed that peptides spanning residues 209-239 (Fas-Pep1 and 251-288 (Fas-Pep2 constitute the two CaM-binding regions of FasDD. To determine the molecular mechanism of interaction, we have characterized the binding of recombinant/synthetic Fas-Pep1 and Fas-Pep2 peptides with CaM. Our data show that both peptides engage the N- and C-terminal lobes of CaM simultaneously. Binding of Fas-Pep1 to CaM is entropically driven while that of Fas-Pep2 to CaM is enthalpically driven, indicating that a combination of electrostatic and hydrophobic forces contribute to the stabilization of the FasDD-CaM complex. Our data suggest that because Fas-Pep1 and Fas-Pep2 are involved in extensive intermolecular contacts with the death domain of FADD, binding of CaM to these regions may hinder its ability to bind to FADD, thus greatly inhibiting the initiation of apoptotic signaling

  10. Oligomerization and chaperone-like activity of Drosophila melanogaster small heat shock protein DmHsp27 and three arginine mutants in the alpha-crystallin domain.

    Science.gov (United States)

    Moutaoufik, Mohamed Taha; Morrow, Geneviève; Maaroufi, Halim; Férard, Céline; Finet, Stéphanie; Tanguay, Robert M

    2017-07-01

    The small Hsp DmHsp27 from Drosophila melanogaster is one of the few small heat shock proteins (sHsps) found within the nucleus. We report that its dimerization is independent of disulfide bond formation and seems to rely on salt bridges. Unlike metazoan sHsps, DmHsp27 forms two populations of oligomers not in equilibrium. Mutations at highly conserved arginine residues in mammalian sHsps have been reported to be associated with protein conformational defects and intracellular aggregation. Independent mutation of three highly conserved arginines (R122, R131, and R135) to glycine in DmHsp27 results in only one population of higher molecular weight form. In vitro, the chaperone-like activity of wild-type DmHsp27 was comparable with that of its two isolated populations and to the single population of the R122G, R131G, and R135G using luciferase as substrate. However, using insulin, the chaperone-like activity of wild-type DmHsp27 was lower than that of R122G and R131G mutants. Altogether, the results characterize wild-type DmHsp27 and its alpha-crystallin domain (ACD) arginine mutants and may give insight into protection mechanism of sHsps.

  11. Purification, crystallization and preliminary x-ray crystallographic studies of RAIDD Death-Domain (DD).

    Science.gov (United States)

    Jang, Tae-ho; Park, Hyun Ho

    2009-06-03

    Caspase-2 activation by formation of PIDDosome is critical for genotoxic stress induced apoptosis. PIDDosome is composed of three proteins, RAIDD, PIDD, and Caspase-2. RAIDD is an adaptor protein containing an N-terminal Caspase-Recruiting-Domain (CARD) and a C-terminal Death-Domain (DD). Its interactions with Caspase-2 and PIDD through CARD and DD respectively and formation of PIDDosome are important for the activation of Caspase-2. RAIDD DD cloned into pET26b vector was expressed in E. coli cells and purified by nickel affinity chromatography and gel filtration. Although it has been known that the most DDs are not soluble in physiological condition, RAIDD DD was soluble and interacts tightly with PIDD DD in physiological condition. The purified RAIDD DD alone has been crystallized. Crystals are trigonal and belong to space group P3(1)21 (or its enantiomorph P3(2)21) with unit-cell parameters a = 56.3, b = 56.3, c = 64.9 A and gamma = 120 degrees . The crystals were obtained at room temperature and diffracted to 2.0 A resolution.

  12. Purification, Crystallization and Preliminary X-ray Crystallographic Studies of RAIDD Death-Domain (DD

    Directory of Open Access Journals (Sweden)

    Hyun Ho Park

    2009-06-01

    Full Text Available Caspase-2 activation by formation of PIDDosome is critical for genotoxic stress induced apoptosis. PIDDosome is composed of three proteins, RAIDD, PIDD, and Caspase-2. RAIDD is an adaptor protein containing an N-terminal Caspase-Recruiting-Domain (CARD and a C-terminal Death-Domain (DD. Its interactions with Caspase-2 and PIDD through CARD and DD respectively and formation of PIDDosome are important for the activation of Caspase-2. RAIDD DD cloned into pET26b vector was expressed in E. coli cells and purified by nickel affinity chromatography and gel filtration. Although it has been known that the most DDs are not soluble in physiological condition, RAIDD DD was soluble and interacts tightly with PIDD DD in physiological condition. The purified RAIDD DD alone has been crystallized. Crystals are trigonal and belong to space group P3121 (or its enantiomorph P3221 with unit-cell parameters a = 56.3, b = 56.3, c = 64.9 Å and γ = 120°. The crystals were obtained at room temperature and diffracted to 2.0 Å resolution.

  13. The structure function of the death domain of human IRAK-M.

    Science.gov (United States)

    Du, Jiangfeng; Nicolaes, Gerry Af; Kruijswijk, Danielle; Versloot, Miranda; van der Poll, Tom; van 't Veer, Cornelis

    2014-12-07

    IRAK-M is an inhibitor of Toll-like receptor signaling that acts by re-directing IRAK-4 activity to TAK1 independent NF-κB activation and by inhibition of IRAK-1/IRAK-2 activity. IRAK-M is expressed in monocytes/macrophages and lung epithelial cells. Lack of IRAK-M in mice greatly improves the resistance to nosocomial pneumonia and lung tumors, which entices IRAK-M as a potential therapeutic target. IRAK-M consists of an N-terminal death domain (DD), a dysfunctional kinase domain and unstructured C-terminal domain. Little is known however on IRAK-M's structure-function relationships. Since death domains provide the important interactions of IRAK-1, IRAK-2 and IRAK-4 molecules, we generated a 3D structure model of the human IRAK-M-DD (residues C5-G119) to guide mutagenesis studies and predict protein-protein interaction points. First we identified the DD residues involved in the endogenous capacity of IRAK-M to activate NF-κB that is displayed upon overexpression in 293T cells. W74 and R97, at distinct interfaces of the IRAK-M-DD, were crucial for this endogenous NF-κB activating capacity, as well as the C-terminal domain (S445-E596) of IRAK-M. Resulting anti-inflammatory A20 and pro-inflammatory IL-8 transcription in 293T cells was W74 dependent, while IL-8 protein expression was dependent on R97 and the TRAF6 binding motif at P478. The IRAK-M-DD W74 and R97 binding interfaces are predicted to interact with opposite sides of IRAK-4-DD's. Secondly we identified DD residues important for the inhibitory action of IRAK-M by stable overexpression of mutants in THP-1 macrophages and H292 lung epithelial cells. IRAK-M inhibited TLR2/4-mediated cytokine production in macrophages in a manner that is largely dependent on W74. R97 was not involved in inhibition of TNF production but was engaged in IL-6 down-regulation by IRAK-M. Protein-interactive residues D19-A23, located in between W74 and R97, were also observed to be crucial for inhibition of TLR2/4 mediated cytokine

  14. OLIGOMERIZATION AND LIQUEFACTION OF ETHYLENE

    African Journals Online (AJOL)

    oligomerize ethylene gas in a packed bed reactor operated at 100-300°C under apressure of 500psi and ... The gas flow was then switched back to N, gas and temperature controller was simultaneously set to the desired reaction temperature. Once the desired .... be considered non-ideal for ethylene oligomerization.

  15. Oligomerization interface of RAGE receptor revealed by MS-monitored hydrogen deuterium exchange.

    Directory of Open Access Journals (Sweden)

    Ewa Sitkiewicz

    Full Text Available Activation of the receptor for advanced glycation end products (RAGE leads to a chronic proinflammatory signal, affecting patients with a variety of diseases. Potentially beneficial modification of RAGE activity requires understanding the signal transduction mechanism at the molecular level. The ligand binding domain is structurally uncoupled from the cytoplasmic domain, suggesting receptor oligomerization is a requirement for receptor activation. In this study, we used hydrogen-deuterium exchange and mass spectrometry to map structural differences between the monomeric and oligomeric forms of RAGE. Our results indicated the presence of a region shielded from exchange in the oligomeric form of RAGE and led to the identification of a new oligomerization interface localized at the linker region between domains C1 and C2. Based on this finding, a model of a RAGE dimer and higher oligomeric state was constructed.

  16. Contribution of trimeric autotransporter C-terminal domains of oligomeric coiled-coil adhesin (Oca) family members YadA, UspA1, EibA, and Hia to translocation of the YadA passenger domain and virulence of Yersinia enterocolitica.

    Science.gov (United States)

    Ackermann, Nikolaus; Tiller, Maximilian; Anding, Gisela; Roggenkamp, Andreas; Heesemann, Jürgen

    2008-07-01

    The Oca family is a novel class of autotransporter-adhesins with highest structural similarity in their C-terminal transmembrane region, which supposedly builds a beta-barrel pore in the outer membrane (OM). The prototype of the Oca family is YadA, an adhesin of Yersinia enterocolitica and Yersinia pseudotuberculosis. YadA forms a homotrimeric lollipop-like structure on the bacterial surface. The C-terminal regions of three YadA monomers form a barrel in the OM and translocate the trimeric N-terminal passenger domain, consisting of stalk, neck, and head region to the exterior. To elucidate the structural and functional role of the C-terminal translocator domain (TLD) and to assess its promiscuous capability with respect to transport of related passenger domains, we constructed chimeric YadA proteins, which consist of the N-terminal YadA passenger domain and C-terminal TLDs of Oca family members UspA1 (Moraxella catarrhalis), EibA (Escherichia coli), and Hia (Haemophilus influenzae). These constructs were expressed in Y. enterocolitica and compared for OM localization, surface exposure, oligomerization, adhesion properties, serum resistance, and mouse virulence. We demonstrate that all chimeric YadA proteins translocated the YadA passenger domain across the OM. Y. enterocolitica strains producing YadA chimeras or wild-type YadA showed comparable binding to collagen and epithelial cells. However, strains producing YadA chimeras were attenuated in serum resistance and mouse virulence. These results demonstrate for the first time that TLDs of Oca proteins of different origin are efficient translocators of the YadA passenger domain and that the cognate TLD of YadA is essential for bacterial survival in human serum and mouse virulence.

  17. The ubiquitin-homology protein, DAP-1, associates with tumor necrosis factor receptor (p60) death domain and induces apoptosis.

    Science.gov (United States)

    Liou, M L; Liou, H C

    1999-04-09

    The tumor necrosis factor receptor, p60 (TNF-R1), transduces death signals via the association of its cytoplasmic domain with several intracellular proteins. By screening a mammalian cDNA library using the yeast two-hybrid cloning technique, we isolated a ubiquitin-homology protein, DAP-1, which specifically interacts with the cytoplasmic death domain of TNF-R1. Sequence analysis reveals that DAP-1 shares striking sequence homology with the yeast SMT3 protein that is essential for the maintenance of chromosome integrity during mitosis (Meluh, P. B., and Koshland, D. (1995) Mol. Biol. Cell 6, 793-807). DAP-1 is nearly identical to PIC1, a protein that interacts with the PML tumor suppressor implicated in acute promyelocytic leukemia (Boddy, M. N., Howe, K., Etkin, L. D., Solomon, E., and Freemont, P. S. (1996) Oncogene 13, 971-982), and the sentrin protein, which associates with the Fas death receptor (Okura, T., Gong, L., Kamitani, T., Wada, T., Okura, I., Wei, C. F., Chang, H. M., and Yeh, E. T. (1996) J. Immunol. 157, 4277-4281). The in vivo interaction between DAP-1 and TNF-R1 was further confirmed in mammalian cells. In transient transfection assays, overexpression of DAP-1 suppresses NF-kappaB/Rel activity in 293T cells, a human kidney embryonic carcinoma cell line. Overexpression of either DAP-1 or sentrin causes apoptosis of TNF-sensitive L929 fibroblast cell line, as well as TNF-resistant osteosarcoma cell line, U2OS. Furthermore, the dominant negative Fas-associated death domain protein (FADD) protein blocks the cell death induced by either DAP-1 or FADD. Collectively, these observations highly suggest a role for DAP-1 in mediating TNF-induced cell death signaling pathways, presumably through the recruitment of FADD death effector.

  18. Nucleotide-binding oligomerization domain 1 regulates Porphyromonas gingivalis-induced vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 expression in endothelial cells through NF-κB pathway.

    Science.gov (United States)

    Wan, M; Liu, J; Ouyang, X

    2015-04-01

    Porphyromonas gingivalis has been shown to actively invade endothelial cells and induce vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) overexpression. Nucleotide-binding oligomerization domain 1 (NOD1) is an intracellular pattern recognition reporter, and its involvement in this process was unknown. This study focused on endothelial cells infected with P. gingivalis, the detection of NOD1 expression and the role that NOD1 plays in the upregulation of VCAM-1 and ICAM-1. The human umbilical vein endothelial cell line (ECV-304) was intruded by P. gingivalis W83, and cells without any treatment were the control group. Expression levels of NOD1, VCAM-1, ICAM-1, phosphorylated P65 between cells with and without treatment on both mRNA and protein levels were compared. Then we examined whether mesodiaminopimelic acid (NOD1 agonist) could increase VCAM-1 and ICAM-1 expression, meanwhile, NOD1 gene silence by RNA interference could reduce VCAM-1, ICAM-1 and phosphorylated P65 release. At last, we examined whether inhibition of NF-κB by Bay117082 could reduce VCAM-1 and ICAM- 1 expression. The mRNA levels were measured by real-time polymerase chain reaction, and protein levels by western blot or electrophoretic mobility shift assays (for phosphorylated P65). P. gingivalis invasion showed significant upregulation of NOD1, VCAM-1 and ICAM-1. NOD1 activation by meso-diaminopimelic acid increased VCAM-1 and ICAM-1 expression, and NOD1 gene silence reduced VCAM-1 and ICAM-1 release markedly. The NF-κB signaling pathway was activated by P. gingivalis, while NOD1 gene silence decreased the activation of NF-κB. Moreover, inhibition of NF-κB reduced VCAM-1 and ICAM-1 expression induced by P. gingivalis in endothelial cells. The results revealed that P. gingivalis induced NOD1 overexpression in endothelial cells and that NOD1 played an important role in the process of VCAM-1 and ICAM-1 expression in endothelial cells infected with P

  19. Oligomerization in health and disease

    CERN Document Server

    Giraldo, Jesus

    2013-01-01

    This special volume of Progress in Molecular Biology and Translational Science focuses on oligomerization in health and disease. Contributions from leading authorities Informs and updates on all the latest developments in the field.

  20. Biophysical characterization of GPCR oligomerization

    DEFF Research Database (Denmark)

    Mathiasen, Signe

    level, and revealed the existence of several dimerization interfaces, each with specific kinetics. Finally we investigated how a property of the membrane solubilizing GPCRs affected oligomerization. We observed a dramatic decrease in oligomer stability with increasing geometrical membrane curvature. We...

  1. Domain-Specific Activation of Death-Associated Intracellular Signalling Cascades by the Cellular Prion Protein in Neuroblastoma Cells.

    Science.gov (United States)

    Vilches, Silvia; Vergara, Cristina; Nicolás, Oriol; Mata, Ágata; Del Río, José A; Gavín, Rosalina

    2016-09-01

    The biological functions of the cellular prion protein remain poorly understood. In fact, numerous studies have aimed to determine specific functions for the different protein domains. Studies of cellular prion protein (PrP(C)) domains through in vivo expression of molecules carrying internal deletions in a mouse Prnp null background have provided helpful data on the implication of the protein in signalling cascades in affected neurons. Nevertheless, understanding of the mechanisms underlying the neurotoxicity induced by these PrP(C) deleted forms is far from complete. To better define the neurotoxic or neuroprotective potential of PrP(C) N-terminal domains, and to overcome the heterogeneity of results due to the lack of a standardized model, we used neuroblastoma cells to analyse the effects of overexpressing PrP(C) deleted forms. Results indicate that PrP(C) N-terminal deleted forms were properly processed through the secretory pathway. However, PrPΔF35 and PrPΔCD mutants led to death by different mechanisms sharing loss of alpha-cleavage and activation of caspase-3. Our data suggest that both gain-of-function and loss-of-function pathogenic mechanisms may be associated with N-terminal domains and may therefore contribute to neurotoxicity in prion disease. Dissecting the molecular response induced by PrPΔF35 may be the key to unravelling the physiological and pathological functions of the prion protein.

  2. Two Overlapping Domains of a Lyssavirus Matrix Protein That Acts on Different Cell Death Pathways ▿

    Science.gov (United States)

    Larrous, Florence; Gholami, Alireza; Mouhamad, Shahul; Estaquier, Jérôme; Bourhy, Hervé

    2010-01-01

    The lyssavirus matrix (M) protein induces apoptosis. The regions of the M protein that are essential for triggering cell death pathways are not yet clearly defined. We therefore compared the M proteins from two viruses that have contrasting characteristics in terms of cellular apoptosis: a genotype 3 lyssavirus, Mokola virus (MOK), and a genotype 1 rabies virus isolated from a dog from Thailand (THA). We identified a 20-amino-acid fragment (corresponding to positions 67 to 86) that retained the cell death activities of the full-length M protein from MOK via both the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and inhibition of cytochrome c oxidase (CcO) activity. We found that the amino acids at positions 77 and 81 have an essential role in triggering these two cell death pathways. Directed mutagenesis demonstrated that the amino acid at position 77 affects CcO activity, whereas the amino acid at position 81 affects TRAIL-dependent apoptosis. Mutations in the full-length M protein that compromised induction of either of these two pathways resulted in delayed apoptosis compared with the time to apoptosis for the nonmutated control. PMID:20631119

  3. Two overlapping domains of a lyssavirus matrix protein that acts on different cell death pathways.

    Science.gov (United States)

    Larrous, Florence; Gholami, Alireza; Mouhamad, Shahul; Estaquier, Jérôme; Bourhy, Hervé

    2010-10-01

    The lyssavirus matrix (M) protein induces apoptosis. The regions of the M protein that are essential for triggering cell death pathways are not yet clearly defined. We therefore compared the M proteins from two viruses that have contrasting characteristics in terms of cellular apoptosis: a genotype 3 lyssavirus, Mokola virus (MOK), and a genotype 1 rabies virus isolated from a dog from Thailand (THA). We identified a 20-amino-acid fragment (corresponding to positions 67 to 86) that retained the cell death activities of the full-length M protein from MOK via both the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and inhibition of cytochrome c oxidase (CcO) activity. We found that the amino acids at positions 77 and 81 have an essential role in triggering these two cell death pathways. Directed mutagenesis demonstrated that the amino acid at position 77 affects CcO activity, whereas the amino acid at position 81 affects TRAIL-dependent apoptosis. Mutations in the full-length M protein that compromised induction of either of these two pathways resulted in delayed apoptosis compared with the time to apoptosis for the nonmutated control.

  4. Formation and biochemical characterization of tube/pelle death domain complexes: critical regulators of postreceptor signaling by the Drosophila toll receptor.

    Science.gov (United States)

    Schiffmann, D A; White, J H; Cooper, A; Nutley, M A; Harding, S E; Jumel, K; Solari, R; Ray, K P; Gay, N J

    1999-09-07

    In Drosophila, the Toll receptor signaling pathway is required for embryonic dorso-ventral patterning and at later developmental stages for innate immune responses. It is thought that dimerization of the receptor by binding of the ligand spätzle causes the formation of a postreceptor activation complex at the cytoplasmic surface of the membrane. Two components of this complex are the adaptor tube and protein kinase pelle. These proteins both have "death domains", protein interaction motifs found in a number of signaling pathways, particularly those involved in apoptotic cell death. It is thought that pelle is bound by tube during formation of the activation complexes, and that this interaction is mediated by the death domains. In this paper, we show using the yeast two-hybrid system that the wild-type tube and pelle death domains bind together. Mutant tube proteins which do not support signaling in the embryo are also unable to bind pelle in the 2-hybrid assay. We have purified proteins corresponding to the death domains of tube and pelle and show that these form corresponding heterodimeric complexes in vitro. Partial proteolysis reveals a smaller core consisting of the minimal death domain sequences. We have studied the tube/pelle interaction with the techniques of surface plasmon resonance, analytical ultracentrifugation and isothermal titration calorimetry. These measurements produce a value of K(d) for the complex of about 0.5 microM.

  5. Jasmonate ZIM-domain (JAZ protein regulates host and nonhost pathogen-induced cell death in tomato and Nicotiana benthamiana.

    Directory of Open Access Journals (Sweden)

    Yasuhiro Ishiga

    Full Text Available The nonhost-specific phytotoxin coronatine (COR produced by several pathovars of Pseudomonas syringae functions as a jasmonic acid-isoleucine (JA-Ile mimic and contributes to disease development by suppressing plant defense responses and inducing reactive oxygen species in chloroplast. It has been shown that the F-box protein CORONATINE INSENSITIVE 1 (COI1 is the receptor for COR and JA-Ile. JASMONATE ZIM DOMAIN (JAZ proteins act as negative regulators for JA signaling in Arabidopsis. However, the physiological significance of JAZ proteins in P. syringae disease development and nonhost pathogen-induced hypersensitive response (HR cell death is not completely understood. In this study, we identified JAZ genes from tomato, a host plant for P. syringae pv. tomato DC3000 (Pst DC3000, and examined their expression profiles in response to COR and pathogens. Most JAZ genes were induced by COR treatment or inoculation with COR-producing Pst DC3000, but not by the COR-defective mutant DB29. Tomato SlJAZ2, SlJAZ6 and SlJAZ7 interacted with SlCOI1 in a COR-dependent manner. Using virus-induced gene silencing (VIGS, we demonstrated that SlJAZ2, SlJAZ6 and SlJAZ7 have no effect on COR-induced chlorosis in tomato and Nicotiana benthamiana. However, SlJAZ2-, SlJAZ6- and SlJAZ7-silenced tomato plants showed enhanced disease-associated cell death to Pst DC3000. Furthermore, we found delayed HR cell death in response to the nonhost pathogen Pst T1 or a pathogen-associated molecular pattern (PAMP, INF1, in SlJAZ2- and SlJAZ6-silenced N. benthamiana. These results suggest that tomato JAZ proteins regulate the progression of cell death during host and nonhost interactions.

  6. Induced oligomerization targets Golgi proteins for degradation in lysosomes.

    Science.gov (United States)

    Tewari, Ritika; Bachert, Collin; Linstedt, Adam D

    2015-12-01

    Manganese protects cells against forms of Shiga toxin by down-regulating the cycling Golgi protein GPP130. Down-regulation occurs when Mn binding causes GPP130 to oligomerize and traffic to lysosomes. To determine how GPP130 is redirected to lysosomes, we tested the role of GGA1 and clathrin, which mediate sorting in the canonical Golgi-to-lysosome pathway. GPP130 oligomerization was induced using either Mn or a self-interacting version of the FKBP domain. Inhibition of GGA1 or clathrin specifically blocked GPP130 redistribution, suggesting recognition of the aggregated GPP130 by the GGA1/clathrin-sorting complex. Unexpectedly, however, GPP130's cytoplasmic domain was not required, and redistribution also occurred after removal of GPP130 sequences needed for its normal cycling. Therefore, to test whether aggregate recognition might be a general phenomenon rather than one involving a specific GPP130 determinant, we induced homo-oligomerization of two unrelated Golgi-targeted constructs using the FKBP strategy. These were targeted to the cis- and trans-Golgi, respectively, using domains from mannosidase-1 and galactosyltransferase. Significantly, upon oligomerization, each redistributed to peripheral punctae and was degraded. This occurred in the absence of detectable UPR activation. These findings suggest the unexpected presence of quality control in the Golgi that recognizes aggregated Golgi proteins and targets them for degradation in lysosomes. © 2015 Tewari et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  7. Birth, growth and death of an antivortex during the propagation of a transverse domain wall in magnetic nanostrips

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, H.Y. [Physics Department, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); HKUST Shenzhen Research Institute, Shenzhen 518057 (China); Wang, X.R., E-mail: phxwan@ust.hk [Physics Department, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); HKUST Shenzhen Research Institute, Shenzhen 518057 (China)

    2014-11-15

    Antivortex birth, growth and death accompanying the propagation of a transverse domain wall (DW) in magnetic nanostrips are observed and analyzed. Antivortex formation is an intrinsic process of a strawberry-like transverse DW originated from magnetostatic interaction. Under an external magnetic field, the wider width region of a DW tends to move faster than the narrower one. This speed mismatch tilts and elongates DW center line. As a result, an antivortex with a well-defined polarity is periodically born near the tail of the DW center line. The antivortex either moves along the center line and dies on the other side of the nanostrip, or grows to its maximum size, detaches itself from the DW, and vanishes eventually. The former route reverses the polarity of DW while the later keeps the DW polarity unchanged. The evolution of the DW structures is analyzed using winding numbers assigned to each topological defects. The phase diagram in the field-width plane is obtained and the damping constant's influence on the phase diagram is discussed. - Highlights: • The magnetostatic interaction leads to a strawberry-like domain wall. • Two types of antivortices evolutions are identified. • Antivortex generation can cause decrease of Walker breakdown field. • The phase diagrams on the field-width plane are obtained.

  8. RIPK3/Fas-Associated Death Domain Axis Regulates Pulmonary Immunopathology to Cryptococcal Infection Independent of Necroptosis

    Directory of Open Access Journals (Sweden)

    Zhenzong Fa

    2017-09-01

    Full Text Available Fas-associated death domain (FADD and receptor interacting protein kinase 3 (RIPK3 are multifunctional regulators of cell death and immune response. Using a mouse model of cryptococcal infection, the roles of FADD and RIPK3 in anti-cryptococcal defense were investigated. Deletion of RIPK3 alone led to increased inflammatory cytokine production in the Cryptococcus neoformans-infected lungs, but in combination with FADD deletion, it led to a robust Th1-biased response with M1-biased macrophage activation. Rather than being protective, these responses led to paradoxical C. neoformans expansion and rapid clinical deterioration in Ripk3−/− and Ripk3−/−Fadd−/− mice. The increased mortality of Ripk3−/− and even more accelerated mortality in Ripk3−/−Fadd−/− mice was attributed to profound pulmonary damage due to neutrophil-dominant infiltration with prominent upregulation of pro-inflammatory cytokines. This phenomenon was partially associated with selective alterations in the apoptotic frequency of some leukocyte subsets, such as eosinophils and neutrophils, in infected Ripk3−/−Fadd−/− mice. In conclusion, our study shows that RIPK3 in concert with FADD serve as physiological “brakes,” preventing the development of excessive inflammation and Th1 bias, which in turn contributes to pulmonary damage and defective fungal clearance. This novel link between the protective effect of FADD and RIPK3 in antifungal defense and sustenance of immune homeostasis may be important for the development of novel immunomodulatory therapies against invasive fungal infections.

  9. Transient oligomerization of the SARS-CoV N protein--implication for virus ribonucleoprotein packaging.

    Science.gov (United States)

    Chang, Chung-ke; Chen, Chia-Min Michael; Chiang, Ming-hui; Hsu, Yen-lan; Huang, Tai-huang

    2013-01-01

    The nucleocapsid (N) phosphoprotein of the severe acute respiratory syndrome coronavirus (SARS-CoV) packages the viral genome into a helical ribonucleocapsid and plays a fundamental role during viral self-assembly. The N protein consists of two structural domains interspersed between intrinsically disordered regions and dimerizes through the C-terminal structural domain (CTD). A key activity of the protein is the ability to oligomerize during capsid formation by utilizing the dimer as a building block, but the structural and mechanistic bases of this activity are not well understood. By disulfide trapping technique we measured the amount of transient oligomers of N protein mutants with strategically located cysteine residues and showed that CTD acts as a primary transient oligomerization domain in solution. The data is consistent with the helical oligomer packing model of N protein observed in crystal. A systematic study of the oligomerization behavior revealed that altering the intermolecular electrostatic repulsion through changes in solution salt concentration or phosphorylation-mimicking mutations affects oligomerization propensity. We propose a biophysical mechanism where electrostatic repulsion acts as a switch to regulate N protein oligomerization.

  10. Transient oligomerization of the SARS-CoV N protein--implication for virus ribonucleoprotein packaging.

    Directory of Open Access Journals (Sweden)

    Chung-ke Chang

    Full Text Available The nucleocapsid (N phosphoprotein of the severe acute respiratory syndrome coronavirus (SARS-CoV packages the viral genome into a helical ribonucleocapsid and plays a fundamental role during viral self-assembly. The N protein consists of two structural domains interspersed between intrinsically disordered regions and dimerizes through the C-terminal structural domain (CTD. A key activity of the protein is the ability to oligomerize during capsid formation by utilizing the dimer as a building block, but the structural and mechanistic bases of this activity are not well understood. By disulfide trapping technique we measured the amount of transient oligomers of N protein mutants with strategically located cysteine residues and showed that CTD acts as a primary transient oligomerization domain in solution. The data is consistent with the helical oligomer packing model of N protein observed in crystal. A systematic study of the oligomerization behavior revealed that altering the intermolecular electrostatic repulsion through changes in solution salt concentration or phosphorylation-mimicking mutations affects oligomerization propensity. We propose a biophysical mechanism where electrostatic repulsion acts as a switch to regulate N protein oligomerization.

  11. Substantial conformational change mediated by charge-triad residues of the death effector domain in protein-protein interactions.

    Directory of Open Access Journals (Sweden)

    Edward C Twomey

    Full Text Available Protein conformational changes are commonly associated with the formation of protein complexes. The non-catalytic death effector domains (DEDs mediate protein-protein interactions in a variety of cellular processes, including apoptosis, proliferation and migration, and glucose metabolism. Here, using NMR residual dipolar coupling (RDC data, we report a conformational change in the DED of the phosphoprotein enriched in astrocytes, 15 kDa (PEA-15 protein in the complex with a mitogen-activated protein (MAP kinase, extracellular regulated kinase 2 (ERK2, which is essential in regulating ERK2 cellular distribution and function in cell proliferation and migration. The most significant conformational change in PEA-15 happens at helices α2, α3, and α4, which also possess the highest flexibility among the six-helix bundle of the DED. This crucial conformational change is modulated by the D/E-RxDL charge-triad motif, one of the prominent structural features of DEDs, together with a number of other electrostatic and hydrogen bonding interactions on the protein surface. Charge-triad motif promotes the optimal orientation of key residues and expands the binding interface to accommodate protein-protein interactions. However, the charge-triad residues are not directly involved in the binding interface between PEA-15 and ERK2.

  12. Cytoskeleton-interacting LIM-domain protein CRP1 suppresses cell proliferation and protects from stress-induced cell death

    International Nuclear Information System (INIS)

    Latonen, Leena; Jaervinen, Paeivi M.; Laiho, Marikki

    2008-01-01

    Members of the cysteine-rich protein (CRP) family are actin cytoskeleton-interacting LIM-domain proteins known to act in muscle cell differentiation. We have earlier found that CRP1, a founding member of this family, is transcriptionally induced by UV radiation in human diploid fibroblasts [M. Gentile, L. Latonen, M. Laiho, Cell cycle arrest and apoptosis provoked by UV radiation-induced DNA damage are transcriptionally highly divergent responses, Nucleic Acids Res. 31 (2003) 4779-4790]. Here we show that CRP1 is induced by growth-inhibitory signals, such as increased cellular density, and cytotoxic stress induced by UV radiation or staurosporine. We found that high levels of CRP1 correlate with differentiation-associated morphology towards the myofibroblast lineage and that expression of ectopic CRP1 suppresses cell proliferation. Following UV- and staurosporine-induced stresses, expression of CRP1 provides a survival advantage evidenced by decreased cellular death and increased cellular metabolic activity and attachment. Our studies identify that CRP1 is a novel stress response factor, and provide evidence for its growth-inhibitory and cytoprotective functions

  13. Dimerization and oligomerization of the chaperone calreticulin

    DEFF Research Database (Denmark)

    Jørgensen, Charlotte S; Ryder, L Rebekka; Steinø, Anne

    2003-01-01

    protein. Using PAGE, urea gradient gel electrophoresis, capillary electrophoresis and MS, we show that dimerization through the SH group can be induced by lowering the pH to 5-6, heating, or under conditions that favour partial unfolding such as urea concentrations above 2.6 m or SDS concentrations above...... that favour partial unfolding or an intramolecular local conformational change that allows oligomerization, resulting in a heterogeneous mixture of oligomers consisting of up to 10 calreticulin monomers. The oligomeric calreticulin was very stable, but oligomerization was partially reversed by addition of 8 m...

  14. Oligomerization and polymerization of the filovirus matrix protein VP40

    International Nuclear Information System (INIS)

    Timmins, Joanna; Schoehn, Guy; Kohlhaas, Christine; Klenk, Hans-Dieter; Ruigrok, Rob W.H.; Weissenhorn, Winfried

    2003-01-01

    The matrix protein VP40 from Ebola virus plays an important role in the assembly process of virus particles by interacting with cellular factors, cellular membranes, and the ribonuclearprotein particle complex. Here we show that the N-terminal domain of VP40 folds into a mixture of two different oligomeric states in vitro, namely hexameric and octameric ringlike structures, as detected by gel filtration chromatography, chemical cross-linking, and electron microscopy. Octamer formation depends largely on the interaction with nucleic acids, which in turn confers in vitro SDS resistance. Refolding experiments with a nucleic acid free N-terminal domain preparation reveal a mostly dimeric form of VP40, which is transformed into an SDS resistant octamer upon incubation with E. coli nucleic acids. In addition, we demonstrate that the N-terminal domain of Marburg virus VP40 also folds into ringlike structures, similar to Ebola virus VP40. Interestingly, Marburg virus VP40 rings reveal a high tendency to polymerize into rods composed of stacked rings. These results may suggest distinct roles for different oligomeric forms of VP40 in the filovirus life cycle

  15. Protein dimerization and oligomerization in biology

    National Research Council Canada - National Science Library

    Matthews, Jacqueline M

    2012-01-01

    .... However, protein function is so often linked to both homo- and hetero-oligomerization and many heterologous interactions likely evolved from homologous interaction, so this volume also covers many...

  16. Reversible peptide oligomerization over nanoscale gold surfaces

    Directory of Open Access Journals (Sweden)

    Kazushige Yokoyama

    2015-11-01

    Full Text Available A selective oligomeric formation of amyloid beta 1-40 (Ab1-40 monomers over a nanogold colloidal surface was investigated. An unfolded Ab1-40 monomer is considered to construct a dimer or trimer based oligomeric form with its hydrophobic segment placing outward under an acidic condition. Under a basic condition, a conformation of Ab is expected to take a folded monomeric form with its hydrophilic segment folded inward, avoiding the networking with residual colloidal particles. The most probable oligomeric form constructed over a 20 nm gold colloidal surface within a 25 ℃ to 65 ℃ temperature range is a dimer based unit and that over 30 or 40 nm gold colloidal surface below 15 ℃ is concluded to be a trimer based unit. However, selective oligomerization was not successfully reproduced under the rest of the conditions. A dipole-induced dipole interaction must cause a flexible structural change between folded and unfolded forms.

  17. The Chloroplastic Protein THF1 Interacts with the Coiled-Coil Domain of the Disease Resistance Protein N′ and Regulates Light-Dependent Cell Death1[OPEN

    Science.gov (United States)

    Sekine, Ken-Taro; Wallon, Thérèse; Sugiwaka, Yuji; Kobayashi, Kappei

    2016-01-01

    One branch of plant immunity is mediated through nucleotide-binding/Leu-rich repeat (NB-LRR) family proteins that recognize specific effectors encoded by pathogens. Members of the I2-like family constitute a well-conserved subgroup of NB-LRRs from Solanaceae possessing a coiled-coil (CC) domain at their N termini. We show here that the CC domains of several I2-like proteins are able to induce a hypersensitive response (HR), a form of programmed cell death associated with disease resistance. Using yeast two-hybrid screens, we identified the chloroplastic protein Thylakoid Formation1 (THF1) as an interacting partner for several I2-like CC domains. Co-immunoprecipitations and bimolecular fluorescence complementation assays confirmed that THF1 and I2-like CC domains interact in planta and that these interactions take place in the cytosol. Several HR-inducing I2-like CC domains have a negative effect on the accumulation of THF1, suggesting that the latter is destabilized by active CC domains. To confirm this model, we investigated N′, which recognizes the coat protein of most Tobamoviruses, as a prototypical member of the I2-like family. Transient expression and gene silencing data indicated that THF1 functions as a negative regulator of cell death and that activation of full-length N′ results in the destabilization of THF1. Consistent with the known function of THF1 in maintaining chloroplast homeostasis, we show that the HR induced by N′ is light-dependent. Together, our results define, to our knowledge, novel molecular mechanisms linking light and chloroplasts to the induction of cell death by a subgroup of NB-LRR proteins. PMID:26951433

  18. The Chloroplastic Protein THF1 Interacts with the Coiled-Coil Domain of the Disease Resistance Protein N' and Regulates Light-Dependent Cell Death.

    Science.gov (United States)

    Hamel, Louis-Philippe; Sekine, Ken-Taro; Wallon, Thérèse; Sugiwaka, Yuji; Kobayashi, Kappei; Moffett, Peter

    2016-05-01

    One branch of plant immunity is mediated through nucleotide-binding/Leu-rich repeat (NB-LRR) family proteins that recognize specific effectors encoded by pathogens. Members of the I2-like family constitute a well-conserved subgroup of NB-LRRs from Solanaceae possessing a coiled-coil (CC) domain at their N termini. We show here that the CC domains of several I2-like proteins are able to induce a hypersensitive response (HR), a form of programmed cell death associated with disease resistance. Using yeast two-hybrid screens, we identified the chloroplastic protein Thylakoid Formation1 (THF1) as an interacting partner for several I2-like CC domains. Co-immunoprecipitations and bimolecular fluorescence complementation assays confirmed that THF1 and I2-like CC domains interact in planta and that these interactions take place in the cytosol. Several HR-inducing I2-like CC domains have a negative effect on the accumulation of THF1, suggesting that the latter is destabilized by active CC domains. To confirm this model, we investigated N', which recognizes the coat protein of most Tobamoviruses, as a prototypical member of the I2-like family. Transient expression and gene silencing data indicated that THF1 functions as a negative regulator of cell death and that activation of full-length N' results in the destabilization of THF1. Consistent with the known function of THF1 in maintaining chloroplast homeostasis, we show that the HR induced by N' is light-dependent. Together, our results define, to our knowledge, novel molecular mechanisms linking light and chloroplasts to the induction of cell death by a subgroup of NB-LRR proteins. © 2016 American Society of Plant Biologists. All Rights Reserved.

  19. An Intramolecular Salt Bridge in Bacillus thuringiensis Cry4Ba Toxin Is Involved in the Stability of Helix α-3, Which Is Needed for Oligomerization and Insecticidal Activity.

    Science.gov (United States)

    Pacheco, Sabino; Gómez, Isabel; Sánchez, Jorge; García-Gómez, Blanca-Ines; Soberón, Mario; Bravo, Alejandra

    2017-10-15

    Bacillus thuringiensis three-domain Cry toxins kill insects by forming pores in the apical membrane of larval midgut cells. Oligomerization of the toxin is an important step for pore formation. Domain I helix α-3 participates in toxin oligomerization. Here we identify an intramolecular salt bridge within helix α-3 of Cry4Ba (D111-K115) that is conserved in many members of the family of three-domain Cry toxins. Single point mutations such as D111K or K115D resulted in proteins severely affected in toxicity. These mutants were also altered in oligomerization, and the mutant K115D was more sensitive to protease digestion. The double point mutant with reversed charges, D111K-K115D, recovered both oligomerization and toxicity, suggesting that this salt bridge is highly important for conservation of the structure of helix α-3 and necessary to promote the correct oligomerization of the toxin. IMPORTANCE Domain I has been shown to be involved in oligomerization through helix α-3 in different Cry toxins, and mutations affecting oligomerization also elicit changes in toxicity. The three-dimensional structure of the Cry4Ba toxin reveals an intramolecular salt bridge in helix α-3 of domain I. Mutations that disrupt this salt bridge resulted in changes in Cry4Ba oligomerization and toxicity, while a double point reciprocal mutation that restored the salt bridge resulted in recovery of toxin oligomerization and toxicity. These data highlight the role of oligomer formation as a key step in Cry4Ba toxicity. Copyright © 2017 American Society for Microbiology.

  20. Higher risk of death among MEN1 patients with mutations in the JunD interacting domain: a Groupe d'etude des Tumeurs Endocrines (GTE) cohort study.

    Science.gov (United States)

    Thevenon, Julien; Bourredjem, Abderrahmane; Faivre, Laurence; Cardot-Bauters, Catherine; Calender, Alain; Murat, Arnaud; Giraud, Sophie; Niccoli, Patricia; Odou, Marie-Françoise; Borson-Chazot, Françoise; Barlier, Anne; Lombard-Bohas, Catherine; Clauser, Eric; Tabarin, Antoine; Parfait, Béatrice; Chabre, Olivier; Castermans, Emilie; Beckers, Albert; Ruszniewski, Philippe; Le Bras, Morgane; Delemer, Brigitte; Bouchard, Philippe; Guilhem, Isabelle; Rohmer, Vincent; Goichot, Bernard; Caron, Philippe; Baudin, Eric; Chanson, Philippe; Groussin, Lionel; Du Boullay, Hélène; Weryha, Georges; Lecomte, Pierre; Penfornis, Alfred; Bihan, Hélène; Archambeaud, Françoise; Kerlan, Véronique; Duron, Françoise; Kuhn, Jean-Marc; Vergès, Bruno; Rodier, Michel; Renard, Michel; Sadoul, Jean-Louis; Binquet, Christine; Goudet, Pierre

    2013-05-15

    Multiple endocrine neoplasia syndrome type 1 (MEN1), which is secondary to mutation of the MEN1 gene, is a rare autosomal-dominant disease that predisposes mutation carriers to endocrine tumors. Although genotype-phenotype studies have so far failed to identify any statistical correlations, some families harbor recurrent tumor patterns. The function of MENIN is unclear, but has been described through the discovery of its interacting partners. Mutations in the interacting domains of MENIN functional partners have been shown to directly alter its regulation abilities. We report on a cohort of MEN1 patients from the Groupe d'étude des Tumeurs Endocrines. Patients with a molecular diagnosis and a clinical follow-up, totaling 262 families and 806 patients, were included. Associations between mutation type, location or interacting factors of the MENIN protein and death as well as the occurrence of MEN1-related tumors were tested using a frailty Cox model to adjust for potential heterogeneity across families. Accounting for the heterogeneity across families, the overall risk of death was significantly higher when mutations affected the JunD interacting domain (adjusted HR = 1.88: 95%-CI = 1.15-3.07). Patients had a higher risk of death from cancers of the MEN1 spectrum (HR = 2.34; 95%-CI = 1.23-4.43). This genotype-phenotype correlation study confirmed the lack of direct genotype-phenotype correlations. However, patients with mutations affecting the JunD interacting domain had a higher risk of death secondary to a MEN1 tumor and should thus be considered for surgical indications, genetic counseling and follow-up.

  1. Bacterial flagellar capping proteins adopt diverse oligomeric states

    Energy Technology Data Exchange (ETDEWEB)

    Postel, Sandra; Deredge, Daniel; Bonsor, Daniel A.; Yu, Xiong; Diederichs, Kay; Helmsing, Saskia; Vromen, Aviv; Friedler, Assaf; Hust, Michael; Egelman, Edward H.; Beckett, Dorothy; Wintrode, Patrick L.; Sundberg, Eric J. (UV); (Braunschweig); (Maryland-MED); (Konstanz); (Maryland); (Hebrew)

    2016-09-24

    Flagella are crucial for bacterial motility and pathogenesis. The flagellar capping protein (FliD) regulates filament assembly by chaperoning and sorting flagellin (FliC) proteins after they traverse the hollow filament and exit the growing flagellum tip. In the absence of FliD, flagella are not formed, resulting in impaired motility and infectivity. Here, we report the 2.2 Å resolution X-ray crystal structure of FliD fromPseudomonas aeruginosa, the first high-resolution structure of any FliD protein from any bacterium. Using this evidence in combination with a multitude of biophysical and functional analyses, we find thatPseudomonasFliD exhibits unexpected structural similarity to other flagellar proteins at the domain level, adopts a unique hexameric oligomeric state, and depends on flexible determinants for oligomerization. Considering that the flagellin filaments on which FliD oligomers are affixed vary in protofilament number between bacteria, our results suggest that FliD oligomer stoichiometries vary across bacteria to complement their filament assemblies.

  2. DNA structure modulates the oligomerization properties of the AAV initiator protein Rep68.

    Directory of Open Access Journals (Sweden)

    Jorge Mansilla-Soto

    2009-07-01

    Full Text Available Rep68 is a multifunctional protein of the adeno-associated virus (AAV, a parvovirus that is mostly known for its promise as a gene therapy vector. In addition to its role as initiator in viral DNA replication, Rep68 is essential for site-specific integration of the AAV genome into human chromosome 19. Rep68 is a member of the superfamily 3 (SF3 helicases, along with the well-studied initiator proteins simian virus 40 large T antigen (SV40-LTag and bovine papillomavirus (BPV E1. Structurally, SF3 helicases share two domains, a DNA origin interaction domain (OID and an AAA(+ motor domain. The AAA(+ motor domain is also a structural feature of cellular initiators and it functions as a platform for initiator oligomerization. Here, we studied Rep68 oligomerization in vitro in the presence of different DNA substrates using a variety of biophysical techniques and cryo-EM. We found that a dsDNA region of the AAV origin promotes the formation of a complex containing five Rep68 subunits. Interestingly, non-specific ssDNA promotes the formation of a double-ring Rep68, a known structure formed by the LTag and E1 initiator proteins. The Rep68 ring symmetry is 8-fold, thus differing from the hexameric rings formed by the other SF3 helicases. However, similiar to LTag and E1, Rep68 rings are oriented head-to-head, suggesting that DNA unwinding by the complex proceeds bidirectionally. This novel Rep68 quaternary structure requires both the DNA binding and AAA(+ domains, indicating cooperativity between these regions during oligomerization in vitro. Our study clearly demonstrates that Rep68 can oligomerize through two distinct oligomerization pathways, which depend on both the DNA structure and cooperativity of Rep68 domains. These findings provide insight into the dynamics and oligomeric adaptability of Rep68 and serve as a step towards understanding the role of this multifunctional protein during AAV DNA replication and site-specific integration.

  3. octamethyl-polyhedral oligomeric silsesquioxanes nanocomposites ...

    Indian Academy of Sciences (India)

    In this study, biodegradable poly(p-dioxanone) (PPDO)/octamethyl-polyhedral oligomeric silsesquioxanes (ome-POSS) nanocomposites were fabricated by the simple solution casting method with various ome-POSS loadings. Scanning electron microscopic observations indicate that ome-POSS is well dispersed in the ...

  4. Electron Microscopy Structural Insights into CPAP Oligomeric Behavior

    DEFF Research Database (Denmark)

    Alvarez-Cabrera, Ana L; Delgado, Sandra; Gil-Carton, David

    2017-01-01

    Centrosomal P4.1-associated protein (CPAP) is a cell cycle regulated protein fundamental for centrosome assembly and centriole elongation. In humans, the region between residues 897-1338 of CPAP mediates interactions with other proteins and includes a homodimerization domain. CPAP mutations cause...... into clearly different regular 3D maps (putatively corresponding to dimers and tetramers) and direct observation of individual images representing other complexes of HsCPAP(897-1338) (i.e., putative flexible monomers and higher-order multimers), we report a dynamic oligomeric behavior of this protein, where...... of different oligomers of CPAP, suggesting further insights to understand how this protein works, contributing to the elucidation of control mechanisms for centriole biogenesis....

  5. The Fas-associated death domain protein/caspase-8/c-FLIP signaling pathway is involved in TNF-induced activation of ERK

    International Nuclear Information System (INIS)

    Lueschen, Silke; Falk, Markus; Scherer, Gudrun; Ussat, Sandra; Paulsen, Maren; Adam-Klages, Sabine

    2005-01-01

    The cytokine TNF activates multiple signaling pathways leading to cellular responses ranging from proliferation and survival to apoptosis. While most of these pathways have been elucidated in detail over the past few years, the molecular mechanism leading to the activation of the MAP kinases ERK remains ill defined and is controversially discussed. Therefore, we have analyzed TNF-induced ERK activation in various human and murine cell lines and show that it occurs in a cell-type-specific manner. In addition, we provide evidence for the involvement of the signaling components Fas-associated death domain protein (FADD), caspase-8, and c-FLIP in the pathway activating ERK in response to TNF. This conclusion is based on the following observations: (I) Overexpression of FADD, caspase-8, or a c-FLIP protein containing the death effector domains only leads to enhanced and prolonged ERK activation after TNF treatment. (II) TNF-induced ERK activation is strongly diminished in the absence of FADD. Interestingly, the enzymatic function of caspase-8 is not required for TNF-induced ERK activation. Additional evidence suggests a role for this pathway in the proliferative response of murine fibroblasts to TNF

  6. Concentration-dependent oligomerization of cross-linked complexes between ferredoxin and ferredoxin–NADP+ reductase

    International Nuclear Information System (INIS)

    Kimata-Ariga, Yoko; Kubota-Kawai, Hisako; Lee, Young-Ho; Muraki, Norifumi; Ikegami, Takahisa; Kurisu, Genji; Hase, Toshiharu

    2013-01-01

    Highlights: •Cross-linked complexes of ferredoxin (Fd) and Fd–NADP + reductase form oligomers. •In the crystal structures, Fd- and FNR moieties swap across the molecules. •The complexes exhibit concentration-dependent oligomerization at sub-milimolar order. -- Abstract: Ferredoxin–NADP + reductase (FNR) forms a 1:1 complex with ferredoxin (Fd), and catalyzes the electron transfer between Fd and NADP + . In our previous study, we prepared a series of site-specifically cross-linked complexes of Fd and FNR, which showed diverse electron transfer properties. Here, we show that X-ray crystal structures of the two different Fd–FNR cross-linked complexes form oligomers by swapping Fd and FNR moieties across the molecules; one complex is a dimer from, and the other is a successive multimeric form. In order to verify whether these oligomeric structures are formed only in crystal, we investigated the possibility of the oligomerization of these complexes in solution. The mean values of the particle size of these cross-linked complexes were shown to increase with the rise of protein concentration at sub-milimolar order, whereas the size of dissociable wild-type Fd:FNR complex was unchanged as analyzed by dynamic light scattering measurement. The oligomerization products were detected by SDS–PAGE after chemical cross-linking of these complexes at the sub-milimolar concentrations. The extent and concentration-dependent profile of the oligomerizaion were differentiated between the two cross-linked complexes. These results show that these Fd–FNR cross-linked complexes exhibit concentration-dependent oligomerization, possibly through swapping of Fd and FNR moieties also in solution. These findings lead to the possibility that some native multi-domain proteins may present similar phenomenon in vivo

  7. Solution NMR investigation of the CD95/FADD homotypic death domain complex suggests lack of engagement of the CD95 C terminus.

    Science.gov (United States)

    Esposito, Diego; Sankar, Andrew; Morgner, Nina; Robinson, Carol V; Rittinger, Katrin; Driscoll, Paul C

    2010-10-13

    We have addressed complex formation between the death domain (DD) of the death receptor CD95 (Fas/APO-1) with the DD of immediate adaptor protein FADD using nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and size-exclusion chromatography with in-line light scattering. We find complexation to be independent of the C-terminal 12 residues of CD95 and insensitive to mutation of residues that engage in the high-order clustering of CD95-DD molecules in a recently reported crystal structure obtained at pH 4. Differential NMR linewidths indicate that the C-terminal region of the CD95 chains remains in a disordered state and (13)C-methyl TROSY data are consistent with a lack of high degree of symmetry for the complex. The overall molecular mass of the complex is inconsistent with that in the crystal structure, and the complex dissociates at pH 4. We discuss these findings using sequence analysis of CD95 orthologs and the effect of FADD mutations on the interaction with CD95. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. Complementary roles of Fas-associated death domain (FADD) and receptor interacting protein kinase-3 (RIPK3) in T-cell homeostasis and antiviral immunity.

    Science.gov (United States)

    Lu, Jennifer V; Weist, Brian M; van Raam, Bram J; Marro, Brett S; Nguyen, Long V; Srinivas, Prathna; Bell, Bryan D; Luhrs, Keith A; Lane, Thomas E; Salvesen, Guy S; Walsh, Craig M

    2011-09-13

    Caspase-8 (casp8) is required for extrinsic apoptosis, and mice deficient in casp8 fail to develop and die in utero while ultimately failing to maintain the proliferation of T cells, B cells, and a host of other cell types. Paradoxically, these failures are not caused by a defect in apoptosis, but by a presumed proliferative function of this protease. Indeed, following mitogenic stimulation, T cells lacking casp8 or its adaptor protein FADD (Fas-associated death domain protein) develop a hyperautophagic morphology, and die a programmed necrosis-like death process termed necroptosis. Recent studies have demonstrated that receptor-interacting protein kinases (RIPKs) RIPK1 and RIPK3 together facilitate TNF-induced necroptosis, but the precise role of RIPKs in the demise of T cells lacking FADD or casp8 activity is unknown. Here we demonstrate that RIPK3 and FADD have opposing and complementary roles in promoting T-cell clonal expansion and homeostasis. We show that the defective proliferation of T cells bearing an interfering form of FADD (FADDdd) is rescued by crossing with RIPK3(-/-) mice, although such rescue ultimately leads to lymphadenopathy. Enhanced recovery of these double-mutant T cells following stimulation demonstrates that FADD, casp8, and RIPK3 are all essential for clonal expansion, contraction, and antiviral responses. Finally, we demonstrate that caspase-mediated cleavage of RIPK1-containing necrosis inducing complexes (necrosomes) is sufficient to prevent necroptosis in the face of death receptor signaling. These studies highlight the "two-faced" nature of casp8 activity, promoting clonal expansion in some situations and apoptotic demise in others.

  9. Polybenzoxazine/Polyhedral Oligomeric Silsesquioxane (POSS Nanocomposites

    Directory of Open Access Journals (Sweden)

    Mohamed Gamal Mohamed

    2016-06-01

    Full Text Available The organic/inorganic hybrid materials from polyhedral oligomeric silsesquioxane (POSS, inorganic nanoparticles and polybenzoxazine (PBZ have received much interesting recently due to their excellent thermal and mechanical properties, flame retardance, low dielectric constant, well-defined inorganic framework at nanosized scale level, and higher performance relative to those of non-hybrid PBZs. This review describes the synthesis, dielectric constants, and thermal, rheological, and mechanical properties of covalently bonded mono- and multifunctionalized benzoxazine POSS hybrids, other functionalized benzoxazine POSS derivatives, and non-covalently (hydrogen bonded benzoxazine POSS composites.

  10. Endocytic pathways mediating oligomeric Aβ42 neurotoxicity

    Directory of Open Access Journals (Sweden)

    Laxton Kevin

    2010-05-01

    Full Text Available Abstract Background One pathological hallmark of Alzheimer's disease (AD is amyloid plaques, composed primarily of amyloid-β peptide (Aβ. Over-production or diminished clearance of the 42 amino acid form of Aβ (Aβ42 in the brain leads to accumulation of soluble Aβ and plaque formation. Soluble oligomeric Aβ (oAβ has recently emerged to be as a likely proximal cause of AD. Results Here we demonstrate that endocytosis is critical in mediating oAβ42-induced neurotoxicity and intraneuronal accumulation of Aβ. Inhibition of clathrin function either with a pharmacological inhibitor, knock-down of clathrin heavy chain expression, or expression of the dominant-negative mutant of clathrin-assembly protein AP180 did not block oAβ42-induced neurotoxicity or intraneuronal accumulation of Aβ. However, inhibition of dynamin and RhoA by expression of dominant negative mutants reduced neurotoxicity and intraneuronal Aβ accumulation. Pharmacologic inhibition of the dynamin-mediated endocytic pathway by genistein also reduced neurotoxicity. Conclusions These data suggest that dynamin-mediated and RhoA-regulated endocytosis are integral steps for oligomeric Aβ42-induced neurotoxicity and intraneuronal Aβ accumulation.

  11. BTB-BACK Domain Protein POB1 Suppresses Immune Cell Death by Targeting Ubiquitin E3 ligase PUB17 for Degradation.

    Directory of Open Access Journals (Sweden)

    Beatriz Orosa

    2017-01-01

    Full Text Available Hypersensitive response programmed cell death (HR-PCD is a critical feature in plant immunity required for pathogen restriction and prevention of disease development. The precise control of this process is paramount to cell survival and an effective immune response. The discovery of new components that function to suppress HR-PCD will be instrumental in understanding the regulation of this fundamental mechanism. Here we report the identification and characterisation of a BTB domain E3 ligase protein, POB1, that functions to suppress HR-PCD triggered by evolutionarily diverse pathogens. Nicotiana benthamiana and tobacco plants with reduced POB1 activity show accelerated HR-PCD whilst those with increased POB1 levels show attenuated HR-PCD. We demonstrate that POB1 dimerization and nuclear localization are vital for its function in HR-PCD suppression. Using protein-protein interaction assays, we identify the Plant U-Box E3 ligase PUB17, a well established positive regulator of plant innate immunity, as a target for POB1-mediated proteasomal degradation. Using confocal imaging and in planta immunoprecipitation assays we show that POB1 interacts with PUB17 in the nucleus and stimulates its degradation. Mutated versions of POB1 that show reduced interaction with PUB17 fail to suppress HR-PCD, indicating that POB1-mediated degradation of PUB17 U-box E3 ligase is an important step for negative regulation of specific immune pathways in plants. Our data reveals a new mechanism for BTB domain proteins in suppressing HR-PCD in plant innate immune responses.

  12. Death and Death Anxiety

    OpenAIRE

    Gonca Karakus; Zehra Ozturk; Lut Tamam

    2012-01-01

    Although death and life concepts seem so different from each other, some believe that death and life as a whole that death is accepted as the goal of life and death completes life. In different cultures, societies and disciplines, there have been very different definitions of death which changes according to personality, age, religion and cultural status of the individual. Attitudes towards death vary dramatically according to individuals. As for the death anxiety, it is a feeling which start...

  13. Arc is a flexible modular protein capable of reversible self-oligomerization

    Science.gov (United States)

    Myrum, Craig; Baumann, Anne; Bustad, Helene J.; Flydal, Marte Innselset; Mariaule, Vincent; Alvira, Sara; Cuéllar, Jorge; Haavik, Jan; Soulé, Jonathan; Valpuesta, José Maria; Márquez, José Antonio; Martinez, Aurora; Bramham, Clive R.

    2015-01-01

    The immediate early gene product Arc (activity-regulated cytoskeleton-associated protein) is posited as a master regulator of long-term synaptic plasticity and memory. However, the physicochemical and structural properties of Arc have not been elucidated. In the present study, we expressed and purified recombinant human Arc (hArc) and performed the first biochemical and biophysical analysis of hArc's structure and stability. Limited proteolysis assays and MS analysis indicate that hArc has two major domains on either side of a central more disordered linker region, consistent with in silico structure predictions. hArc's secondary structure was estimated using CD, and stability was analysed by CD-monitored thermal denaturation and differential scanning fluorimetry (DSF). Oligomerization states under different conditions were studied by dynamic light scattering (DLS) and visualized by AFM and EM. Biophysical analyses show that hArc is a modular protein with defined secondary structure and loose tertiary structure. hArc appears to be pyramid-shaped as a monomer and is capable of reversible self-association, forming large soluble oligomers. The N-terminal domain of hArc is highly basic, which may promote interaction with cytoskeletal structures or other polyanionic surfaces, whereas the C-terminal domain is acidic and stabilized by ionic conditions that promote oligomerization. Upon binding of presenilin-1 (PS1) peptide, hArc undergoes a large structural change. A non-synonymous genetic variant of hArc (V231G) showed properties similar to the wild-type (WT) protein. We conclude that hArc is a flexible multi-domain protein that exists in monomeric and oligomeric forms, compatible with a diverse, hub-like role in plasticity-related processes. PMID:25748042

  14. The N-terminus of TDP-43 promotes its oligomerization and enhances DNA binding affinity

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chung-ke [Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan (China); Wu, Tzong-Huah [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China); Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Biochemistry, Academia Sinica, Taipei 115, Taiwan (China); Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan (China); Wu, Chu-Ya [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China); Graduate Institute of Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Chiang, Ming-hui; Toh, Elsie Khai-Woon [Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan (China); Hsu, Yin-Chih; Lin, Ku-Feng [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China); Liao, Yu-heng [Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan (China); Huang, Tai-huang, E-mail: bmthh@gate.sinica.edu.tw [Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan (China); Department of Physics, National Taiwan Normal University, Taipei 106, Taiwan (China); Huang, Joseph Jen-Tse, E-mail: jthuang@chem.sinica.edu.tw [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer The N-terminus of TDP-43 contains an independently folded structural domain (NTD). Black-Right-Pointing-Pointer The structural domains of TDP-43 are arranged in a beads-on-a-string fashion. Black-Right-Pointing-Pointer The NTD promotes TDP-43 oligomerization in a concentration-dependent manner. Black-Right-Pointing-Pointer The NTD may assist nucleic acid-binding activity of TDP-43. -- Abstract: TDP-43 is a DNA/RNA-binding protein associated with different neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD-U). Here, the structural and physical properties of the N-terminus on TDP-43 have been carefully characterized through a combination of nuclear magnetic resonance (NMR), circular dichroism (CD) and fluorescence anisotropy studies. We demonstrate for the first time the importance of the N-terminus in promoting TDP-43 oligomerization and enhancing its DNA-binding affinity. An unidentified structural domain in the N-terminus is also disclosed. Our findings provide insights into the N-terminal domain function of TDP-43.

  15. Senescence-associated barley NAC (NAM, ATAF1,2, CUC) transcription factor interacts with radical-induced cell death 1 through a disordered regulatory domain

    DEFF Research Database (Denmark)

    Kjaersgaard, Trine; Jensen, Michael K; Christiansen, Michael W

    2011-01-01

    as a transcriptional activator suggesting that an involvement of HvNAC013 and HvNAC005 in senescence will be different. HvNAC013 interacted with barley radical-induced cell death 1 (RCD1) via the very C-terminal part of its TRD, outside of the region containing the LP motif. No significant secondary structure...... (NAM, ATAF1,2, CUC) TF family are up-regulated during senescence in barley (Hordeum vulgare). Both HvNAC005 and HvNAC013 bound the conserved NAC DNA target sequence. Computational and biophysical analyses showed that both proteins are intrinsically disordered in their large C-terminal domains, which...... was induced in the HvNAC013 TRD upon interaction with RCD1. RCD1 also interacted with regions dominated by intrinsic disorder in TFs of the MYB and basic helix-loop-helix families. We propose that RCD1 is a regulatory protein capable of interacting with many different TFs by exploiting their intrinsic...

  16. Free-energy landscape of protein oligomerization from atomistic simulations

    Science.gov (United States)

    Barducci, Alessandro; Bonomi, Massimiliano; Prakash, Meher K.; Parrinello, Michele

    2013-01-01

    In the realm of protein–protein interactions, the assembly process of homooligomers plays a fundamental role because the majority of proteins fall into this category. A comprehensive understanding of this multistep process requires the characterization of the driving molecular interactions and the transient intermediate species. The latter are often short-lived and thus remain elusive to most experimental investigations. Molecular simulations provide a unique tool to shed light onto these complex processes complementing experimental data. Here we combine advanced sampling techniques, such as metadynamics and parallel tempering, to characterize the oligomerization landscape of fibritin foldon domain. This system is an evolutionarily optimized trimerization motif that represents an ideal model for experimental and computational mechanistic studies. Our results are fully consistent with previous experimental nuclear magnetic resonance and kinetic data, but they provide a unique insight into fibritin foldon assembly. In particular, our simulations unveil the role of nonspecific interactions and suggest that an interplay between thermodynamic bias toward native structure and residual conformational disorder may provide a kinetic advantage. PMID:24248370

  17. Topology and Oligomerization of Mono- and Oligomeric Proteins Regulate Their Half-Lives in the Cell.

    Science.gov (United States)

    Mallik, Saurav; Kundu, Sudip

    2018-06-05

    To find additional structural constraints (besides disordered segments) that regulate protein half-life in the cell, we herein assess the influence of native topology of monomeric and sequestration of oligomeric proteins into multimeric complexes in yeast, human, and mouse. Native topology acts as a molecular marker of globular protein's mechanical resistance and consequently captures their half-life variations on genome scale. Sequestration into multimeric complexes elongates oligomeric protein half-life in the cell, presumably by burying ubiquitinoylation sites and disordered segments required for proteasomal recognition. The latter effect is stronger for proteins associated with multiple complexes and for those binding early during complex self-assembly, including proteins that oligomerize with large proportions of surface buried. After gene duplication, diversification of topology and sequestration into non-identical sets of complexes alter half-lives of paralogous proteins during the course of evolution. Thus, native topology and sequestration into multimeric complexes reflect designing principles of proteins to regulate their half-lives. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Polymorphism and mesomorphism of oligomeric surfactants: effect of the degree of oligomerization.

    Science.gov (United States)

    Jurašin, D; Pustak, A; Habuš, I; Šmit, I; Filipović-Vinceković, N

    2011-12-06

    A series of cationic oligomeric surfactants (quaternary dodecyldimethylammonium ions with two, three, or four chains connected by an ethylene spacer at the headgroup level, abbreviated as dimer, trimer, and tetramer) were synthesized and characterized. The influence of the degree of oligomerization on their polymorphic and mesomorphic properties was investigated by means of X-ray diffraction, polarizing optical microscopy, thermogravimetry, and differential scanning calorimetry. All compounds display layered arrangements with interdigitated dodecyl chains. The increase in the degree of oligomerization increases the interlayer distance and decreases the ordering in the solid phase; whereas the dimer sample is fully crystalline with well-developed 3D ordering and the trimer and tetramer crystallize as highly ordered crystal smectic phases. The number of thermal phase transitions and sequence of phases are markedly affected by the number of dodecyl chains. Anhydrous samples exhibit polymorphism and thermotropic mesomorphism of the smectic type, with the exception of the tetramer that displays only transitions at higher temperature associated with decomposition and melting. All hydrated compounds form lyotropic mesophases showing reversible phase transitions upon heating and cooling. The sequence of liquid-crystalline phases for the dimer, typical of concentrated ionic surfactant systems, comprises a hexagonal phase at lower temperatures and a smectic phase at higher temperatures. In contrast, the trimer and tetramer reveal textures of the hexagonal phase. © 2011 American Chemical Society

  19. Genetic noise control via protein oligomerization

    Energy Technology Data Exchange (ETDEWEB)

    Ghim, C; Almaas, E

    2008-06-12

    Gene expression in a cell entails random reaction events occurring over disparate time scales. Thus, molecular noise that often results in phenotypic and population-dynamic consequences sets a fundamental limit to biochemical signaling. While there have been numerous studies correlating the architecture of cellular reaction networks with noise tolerance, only a limited effort has been made to understand the dynamical role of protein-protein associations. We have developed a fully stochastic model for the positive feedback control of a single gene, as well as a pair of genes (toggle switch), integrating quantitative results from previous in vivo and in vitro studies. In particular, we explicitly account for the fast protein binding-unbinding kinetics, RNA polymerases, and the promoter/operator sequences of DNA. We find that the overall noise-level is reduced and the frequency content of the noise is dramatically shifted to the physiologically irrelevant high-frequency regime in the presence of protein dimerization. This is independent of the choice of monomer or dimer as transcription factor and persists throughout the multiple model topologies considered. For the toggle switch, we additionally find that the presence of a protein dimer, either homodimer or heterodimer, may significantly reduce its intrinsic switching rate. Hence, the dimer promotes the robust function of bistable switches by preventing the uninduced (induced) state from randomly being induced (uninduced). The specific binding between regulatory proteins provides a buffer that may prevent the propagation of fluctuations in genetic activity. The capacity of the buffer is a non-monotonic function of association-dissociation rates. Since the protein oligomerization per se does not require extra protein components to be expressed, it provides a basis for the rapid control of intrinsic or extrinsic noise. The stabilization of phenotypically important toggle switches, and nested positive feedback loops in

  20. Cartilage oligomeric matrix protein in patients with juvenile idiopathic arthritis

    DEFF Research Database (Denmark)

    Bjørnhart, Birgitte; Juul, Anders; Nielsen, Susan

    2009-01-01

    Cartilage oligomeric matrix protein (COMP) has been identified as a prognostic marker of progressive joint destruction in rheumatoid arthritis. In this population based study we evaluated associations between plasma concentrations of COMP, disease activity, and growth velocity in patients...

  1. Protic Cationic Oligomeric Ionic Liquids of the Urethane Type

    DEFF Research Database (Denmark)

    Shevchenko, V. V.; Stryutsky, A. V.; Klymenko, N. S.

    2014-01-01

    Protic oligomeric cationic ionic liquids of the oligo(ether urethane) type are synthesized via the reaction of an isocyanate prepolymer based on oligo(oxy ethylene)glycol with M = 1000 with hexamethylene-diisocyanate followed by blocking of the terminal isocyanate groups with the use of amine...... derivatives of imidazole, pyridine, and 3-methylpyridine and neutralization of heterocycles with ethanesulfonic acid and p-toluenesulfonic acid. The structures and properties of the synthesized oligomeric ionic liquids substantially depend on the structures of the ionic groups. They are amorphous at room...... temperature, but ethanesulfonate imidazolium and pyridinium oligomeric ionic liquids form a low melting crystalline phase. The proton conductivities of the oligomeric ionic liquids are determined by the type of cation in the temperature range 80-120 degrees C under anhydrous conditions and vary within five...

  2. The Pseudo signal peptide of the corticotropin-releasing factor receptor type 2A prevents receptor oligomerization.

    Science.gov (United States)

    Teichmann, Anke; Rutz, Claudia; Kreuchwig, Annika; Krause, Gerd; Wiesner, Burkhard; Schülein, Ralf

    2012-08-03

    N-terminal signal peptides mediate the interaction of native proteins with the translocon complex of the endoplasmic reticulum membrane and are cleaved off during early protein biogenesis. The corticotropin-releasing factor receptor type 2a (CRF(2(a))R) possesses an N-terminal pseudo signal peptide, which represents a so far unique domain within the large protein family of G protein-coupled receptors (GPCRs). In contrast to a conventional signal peptide, the pseudo signal peptide remains uncleaved and consequently forms a hydrophobic extension at the N terminus of the receptor. The functional consequence of the presence of the pseudo signal peptide is not understood. Here, we have analyzed the significance of this domain for receptor dimerization/oligomerization in detail. To this end, we took the CRF(2(a))R and the homologous corticotropin-releasing factor receptor type 1 (CRF(1)R) possessing a conventional cleaved signal peptide and conducted signal peptide exchange experiments. Using single cell and single molecule imaging methods (fluorescence resonance energy transfer and fluorescence cross-correlation spectroscopy, respectively) as well as biochemical experiments, we obtained two novel findings; we could show that (i) the CRF(2(a))R is expressed exclusively as a monomer, and (ii) the presence of the pseudo signal peptide prevents its oligomerization. Thus, we have identified a novel functional domain within the GPCR protein family, which plays a role in receptor oligomerization and which may be useful to study the functional significance of this process in general.

  3. The Agrobacterium tumefaciens Transcription Factor BlcR Is Regulated via Oligomerization

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yi; Fiscus, Valena; Meng, Wuyi; Zheng, Zhida; Zhang, Lian-Hui; Fuqua, Clay; Chen, Lingling (IMCB-Singapore); (Indiana)

    2012-02-08

    The Agrobacterium tumefaciens BlcR is a member of the emerging isocitrate lyase transcription regulators that negatively regulates metabolism of {gamma}-butyrolactone, and its repressing function is relieved by succinate semialdehyde (SSA). Our crystal structure showed that BlcR folded into the DNA- and SSA-binding domains and dimerized via the DNA-binding domains. Mutational analysis identified residues, including Phe{sup 147}, that are important for SSA association; BlcR{sup F147A} existed as tetramer. Two BlcR dimers bound to target DNA and in a cooperative manner, and the distance between the two BlcR-binding sequences in DNA was critical for BlcR-DNA association. Tetrameric BlcR{sup F147A} retained DNA binding activity, and importantly, this activity was not affected by the distance separating the BlcR-binding sequences in DNA. SSA did not dissociate tetrameric BlcR{sup F147A} or BlcR{sup F147A}-DNA. As well as in the SSA-binding site, Phe{sup 147} is located in a structurally flexible loop that may be involved in BlcR oligomerization. We propose that SSA regulates BlcR DNA-binding function via oligomerization.

  4. Coiled-coil domain-dependent homodimerization of intracellular barley immune receptors defines a minimal functional module for triggering cell death

    NARCIS (Netherlands)

    Maekawa, T.; Cheng, W.; Spiridon, L.N.; Töller, A.; Lukasik, E.; Saijo, Y.; Liu, P.; Shen, Q.H.; Micluta, M.A.; Somssich, I.E.; Takken, F.L.W.; Petrescu, A.J.; Chai, J.; Schulze-Lefert, P.

    2011-01-01

    Plants and animals have evolved structurally related innate immune sensors, designated NLRs, to detect intracellular nonself molecules. NLRs are modular, consisting of N-terminal coiled-coil (CC) or TOLL/interleukin-1 receptor (TIR) domains, a central nucleotide-binding (NB) domain, and C-terminal

  5. Crystal structures from the Plasmodium peroxiredoxins: new insights into oligomerization and product binding.

    Science.gov (United States)

    Qiu, Wei; Dong, Aiping; Pizarro, Juan C; Botchkarsev, Alexei; Min, Jinrong; Wernimont, Amy K; Hills, Tanya; Hui, Raymond; Artz, Jennifer D

    2012-03-19

    Plasmodium falciparum is the protozoan parasite primarily responsible for more than one million malarial deaths, annually, and is developing resistance to current therapies. Throughout its lifespan, the parasite is subjected to oxidative attack, so Plasmodium antioxidant defences are essential for its survival and are targets for disease control. To further understand the molecular aspects of the Plasmodium redox system, we solved 4 structures of Plasmodium peroxiredoxins (Prx). Our study has confirmed PvTrx-Px1 to be a hydrogen peroxide (H2O2)-sensitive peroxiredoxin. We have identified and characterized the novel toroid octameric oligomer of PyTrx-Px1, which may be attributed to the interplay of several factors including: (1) the orientation of the conserved surface/buried arginine of the NNLA(I/L)GRS-loop; and (2) the C-terminal tail positioning (also associated with the aforementioned conserved loop) which facilitates the intermolecular hydrogen bond between dimers (in an A-C fashion). In addition, a notable feature of the disulfide bonds in some of the Prx crystal structures is discussed. Finally, insight into the latter stages of the peroxiredoxin reaction coordinate is gained. Our structure of PyPrx6 is not only in the sulfinic acid (RSO2H) form, but it is also with glycerol bound in a way (not previously observed) indicative of product binding. The structural characterization of Plasmodium peroxiredoxins provided herein provides insight into their oligomerization and product binding which may facilitate the targeting of these antioxidant defences. Although the structural basis for the octameric oligomerization is further understood, the results yield more questions about the biological implications of the peroxiredoxin oligomerization, as multiple toroid configurations are now known. The crystal structure depicting the product bound active site gives insight into the overoxidation of the active site and allows further characterization of the leaving group

  6. Moyamoya disease-associated protein mysterin/RNF213 is a novel AAA+ ATPase, which dynamically changes its oligomeric state

    Science.gov (United States)

    Morito, Daisuke; Nishikawa, Kouki; Hoseki, Jun; Kitamura, Akira; Kotani, Yuri; Kiso, Kazumi; Kinjo, Masataka; Fujiyoshi, Yoshinori; Nagata, Kazuhiro

    2014-03-01

    Moyamoya disease is an idiopathic human cerebrovascular disorder that is characterized by progressive stenosis and abnormal collateral vessels. We recently identified mysterin/RNF213 as its first susceptibility gene, which encodes a 591-kDa protein containing enzymatically active P-loop ATPase and ubiquitin ligase domains and is involved in proper vascular development in zebrafish. Here we demonstrate that mysterin further contains two tandem AAA+ ATPase modules and forms huge ring-shaped oligomeric complex. AAA+ ATPases are known to generally mediate various biophysical and mechanical processes with the characteristic ring-shaped structure. Fluorescence correlation spectroscopy and biochemical evaluation suggested that mysterin dynamically changes its oligomeric forms through ATP/ADP binding and hydrolysis cycles. Thus, the moyamoya disease-associated gene product is a unique protein that functions as ubiquitin ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell.

  7. Moyamoya disease-associated protein mysterin/RNF213 is a novel AAA+ ATPase, which dynamically changes its oligomeric state

    Science.gov (United States)

    Morito, Daisuke; Nishikawa, Kouki; Hoseki, Jun; Kitamura, Akira; Kotani, Yuri; Kiso, Kazumi; Kinjo, Masataka; Fujiyoshi, Yoshinori; Nagata, Kazuhiro

    2014-01-01

    Moyamoya disease is an idiopathic human cerebrovascular disorder that is characterized by progressive stenosis and abnormal collateral vessels. We recently identified mysterin/RNF213 as its first susceptibility gene, which encodes a 591-kDa protein containing enzymatically active P-loop ATPase and ubiquitin ligase domains and is involved in proper vascular development in zebrafish. Here we demonstrate that mysterin further contains two tandem AAA+ ATPase modules and forms huge ring-shaped oligomeric complex. AAA+ ATPases are known to generally mediate various biophysical and mechanical processes with the characteristic ring-shaped structure. Fluorescence correlation spectroscopy and biochemical evaluation suggested that mysterin dynamically changes its oligomeric forms through ATP/ADP binding and hydrolysis cycles. Thus, the moyamoya disease-associated gene product is a unique protein that functions as ubiquitin ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell. PMID:24658080

  8. Neonatal Death

    Science.gov (United States)

    ... Home > Complications & Loss > Loss & grief > Neonatal death Neonatal death E-mail to a friend Please fill in ... cope with your baby’s death. What is neonatal death? Neonatal death is when a baby dies in ...

  9. Involvement of C-Terminal Histidines in Soybean PM1 Protein Oligomerization and Cu2+ Binding.

    Science.gov (United States)

    Liu, Guobao; Liu, Ke; Gao, Yang; Zheng, Yizhi

    2017-06-01

    Late embryogenesis abundant (LEA) proteins are widely distributed among plant species, where they contribute to abiotic stress tolerance. LEA proteins can be classified into seven groups according to conserved sequence motifs. The PM1 protein from soybean, which belongs to the Pfam LEA_1 group, has been shown previously to be at least partially natively unfolded, to bind metal ions and potentially to stabilize proteins and membranes. Here, we investigated the role of the PM1 C-terminal domain and in particular the multiple histidine residues in this half of the protein. We constructed recombinant plasmids expressing full-length PM1 and two truncated forms, PM1-N and PM1-C, which represent the N- and C-terminal halves of the protein, respectively. Immunoblotting and cross-linking experiments showed that full-length PM1 forms oligomers and high molecular weight (HMW) complexes in vitro and in vivo, while PM1-C, but not PM1-N, also formed oligomers and HMW complexes in vitro. When the histidine residues in PM1 and PM1-C were chemically modified, oligomerization was abolished, suggesting that histidines play a key role in this process. Furthermore, we demonstrated that high Cu2+ concentrations promote oligomerization and induce PM1 and PM1-C to form HMW complexes. Therefore, we speculate that PM1 proteins not only maintain ion homeostasis in the cytoplasm, but also potentially stabilize and protect other proteins during abiotic stress by forming a large, oligomeric molecular shield around biological targets. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  10. Cartilage oligomeric matrix protein enhances the vascularization of acellular nerves

    Directory of Open Access Journals (Sweden)

    Wei-ling Cui

    2016-01-01

    Full Text Available Vascularization of acellular nerves has been shown to contribute to nerve bridging. In this study, we used a 10-mm sciatic nerve defect model in rats to determine whether cartilage oligomeric matrix protein enhances the vascularization of injured acellular nerves. The rat nerve defects were treated with acellular nerve grafting (control group alone or acellular nerve grafting combined with intraperitoneal injection of cartilage oligomeric matrix protein (experimental group. As shown through two-dimensional imaging, the vessels began to invade into the acellular nerve graft from both anastomotic ends at day 7 post-operation, and gradually covered the entire graft at day 21. The vascular density, vascular area, and the velocity of revascularization in the experimental group were all higher than those in the control group. These results indicate that cartilage oligomeric matrix protein enhances the vascularization of acellular nerves.

  11. An engineered allosteric switch in leucine-zipper oligomerization.

    Science.gov (United States)

    Gonzalez, L; Plecs, J J; Alber, T

    1996-06-01

    Controversy remains about the role of core side-chain packing in specifying protein structure. To investigate the influence of core packing on the oligomeric structure of a coiled coil, we engineered a GCN4 leucine zipper mutant that switches from two to three strands upon binding the hydrophobic ligands cyclohexane and benzene. In solution these ligands increased the apparent thermal stability and the oligomerization order of the mutant leucine zipper. The crystal structure of the peptide-benzene complex shows a single benzene molecule bound at the engineered site in the core of the trimer. These results indicate that coiled coils are well-suited to function as molecular switches and emphasize that core packing is an important determinant of oligomerization specificity.

  12. Genetic noise control via protein oligomerization

    Directory of Open Access Journals (Sweden)

    Almaas Eivind

    2008-11-01

    Full Text Available Abstract Background Gene expression in a cell entails random reaction events occurring over disparate time scales. Thus, molecular noise that often results in phenotypic and population-dynamic consequences sets a fundamental limit to biochemical signaling. While there have been numerous studies correlating the architecture of cellular reaction networks with noise tolerance, only a limited effort has been made to understand the dynamic role of protein-protein interactions. Results We have developed a fully stochastic model for the positive feedback control of a single gene, as well as a pair of genes (toggle switch, integrating quantitative results from previous in vivo and in vitro studies. In particular, we explicitly account for the fast binding-unbinding kinetics among proteins, RNA polymerases, and the promoter/operator sequences of DNA. We find that the overall noise-level is reduced and the frequency content of the noise is dramatically shifted to the physiologically irrelevant high-frequency regime in the presence of protein dimerization. This is independent of the choice of monomer or dimer as transcription factor and persists throughout the multiple model topologies considered. For the toggle switch, we additionally find that the presence of a protein dimer, either homodimer or heterodimer, may significantly reduce its random switching rate. Hence, the dimer promotes the robust function of bistable switches by preventing the uninduced (induced state from randomly being induced (uninduced. Conclusion The specific binding between regulatory proteins provides a buffer that may prevent the propagation of fluctuations in genetic activity. The capacity of the buffer is a non-monotonic function of association-dissociation rates. Since the protein oligomerization per se does not require extra protein components to be expressed, it provides a basis for the rapid control of intrinsic or extrinsic noise. The stabilization of regulatory circuits

  13. An Asymmetric Deuterium Labeling Strategy to Identify Interprotomer and Intraprotomer NOEs in Oligomeric Proteins

    International Nuclear Information System (INIS)

    Jasanoff, Alan

    1998-01-01

    A major difficulty in determining the structure of an oligomeric protein by NMR is the problem of distinguishing inter- from intraprotomer NOEs. In order to address this issue in studies of the 27 kD compact trimeric domain of the MHC class II-associated invariant chain, we compared the 13C NOESY-HSQC spectrum of a uniformly 13C-labeled trimer with the spectrum of the same trimer labeled with 13C in only one protomer, and with deuterium in the other two protomers. The spectrum of the unmixed trimer included both inter- and intraprotomer NOEs while the spectrum of the mixed trimer included only intraprotomer peaks. NOEs clearly absent from the spectrum of the mixed trimer could be confidently assigned to interprotomer interactions. Asymmetrically labeled trimers were isolated by refolding a 13C-labeled shorter form of the protein with a 2H-labeled longer form, chromatographically purifying trimers with only one short chain, and then processing with trypsin to yield only protomers with the desired N- and C-termini. In contrast to earlier studies, in which statistical mixtures of differently labeled protomers were analyzed, our procedure generated only a well-defined 1:2 oligomer, and no other mixed oligomers were present. This increased the maximum possible concentration of NMR-active protomers and thus the sensitivity of the experiments. Related methods should be applicable to many oligomeric proteins, particularly those with slow protomer exchange rates

  14. Conformational detection of p53's oligomeric state by FlAsH Fluorescence.

    Science.gov (United States)

    Webber, Tawnya M; Allen, Andrew C; Ma, Wai Kit; Molloy, Rhett G; Kettelkamp, Charisse N; Dow, Caitlin A; Gage, Matthew J

    2009-06-19

    The p53 tumor suppressor protein is a critical checkpoint in prevention of tumor formation, and the function of p53 is dependent on proper formation of the active tetramer. In vitro studies have shown that p53 binds DNA most efficiently as a tetramer, though inactive p53 is predicted to be monomeric in vivo. We demonstrate that FlAsH binding can be used to distinguish between oligomeric states of p53, providing a potential tool to explore p53 oligomerization in vivo. The FlAsH tetra-cysteine binding motif has been incorporated along the dimer and tetramer interfaces in the p53 tetramerization domain to create reporters for the dimeric and tetrameric states of p53, though the geometry of the four cysteines is critical for efficient FlAsH binding. Furthermore, we demonstrate that FlAsH binding can be used to monitor tetramer formation in real-time. These results demonstrate the potential for using FlAsH fluorescence to monitor protein-protein interactions in vivo.

  15. High Content Analysis of Compositional Heterogeneities to Study GPCR Oligomerization

    DEFF Research Database (Denmark)

    Walsh, Samuel McEwen

    In this thesis I demonstrate how the natural compositional heterogeneities of synthetic and living cell model systems can be used to quantitate the mechanics of G-protein coupled receptor (GPCR) oligomerization with Förster resonance energy transfer (FRET). The thesis is structured around three a...

  16. BIM-Mediated Membrane Insertion of the BAK Pore Domain Is an Essential Requirement for Apoptosis

    Directory of Open Access Journals (Sweden)

    Kathrin Weber

    2013-10-01

    Full Text Available BAK activation represents a key step during apoptosis, but how it converts into a mitochondria-permeabilizing pore remains unclear. By further delineating the structural rearrangements involved, we reveal that BAK activation progresses through a series of independent steps: BH3-domain exposure, N-terminal change, oligomerization, and membrane insertion. Employing a “BCL-XL-addiction” model, we show that neutralization of BCL-XL by the BH3 mimetic ABT-737 resulted in death only when cells were reconstituted with BCL-XL:BAK, but not BCL-2/ BCL-XL:BIM complexes. Although this resembles the indirect model, release of BAK from BCL-XL did not result in spontaneous adoption of the pore conformation. Commitment to apoptosis required association of the direct activator BIM with oligomeric BAK promoting its conversion to a membrane-inserted pore. The sequential nature of this cascade provides multiple opportunities for other BCL-2 proteins to interfere with or promote BAK activation and unites aspects of the indirect and direct activation models.

  17. Precise mapping of the CD95 pre-ligand assembly domain.

    Directory of Open Access Journals (Sweden)

    Valérie Edmond

    Full Text Available Pre-association of CD95 at the plasma membrane is mandatory for efficient death receptor signaling. This homotrimerization occurs through self-association of an extracellular domain called the pre-ligand assembly domain (PLAD. Using novel molecular and cellular tools, we confirmed that CD95-PLAD is necessary to promote CD95 multimerization and plays a pivotal role in the transmission of apoptotic signals. However, while a human CD95 mutant deleted of the previously described PLAD domain (amino acids 1 to 66 fails to interact with its wild-type counterpart and trigger autonomous cell death, deletion of amino acids 1 to 42 does not prevent homo- or hetero (human/mouse-oligomerization of CD95, and thus does not alter transmission of the apoptotic signal. Overall, these findings indicate that the region between amino acids 43 to 66 corresponds to the minimal motif involved in CD95 homotypic interaction and is necessary to convey an efficient apoptotic signal. Interfering with this PLAD may represent a new therapeutic strategy for altering CD95-induced apoptotic and non-apoptotic signals.

  18. Up-regulated Ectonucleotidases in Fas-Associated Death Domain Protein- and Receptor-Interacting Protein Kinase 1-Deficient Jurkat Leukemia Cells Counteract Extracellular ATP/AMP Accumulation via Pannexin-1 Channels during Chemotherapeutic Drug-Induced Apoptosis.

    Science.gov (United States)

    Boyd-Tressler, Andrea M; Lane, Graham S; Dubyak, George R

    2017-07-01

    Pannexin-1 (Panx1) channels mediate the efflux of ATP and AMP from cancer cells in response to induction of extrinsic apoptosis by death receptors or intrinsic apoptosis by chemotherapeutic agents. We previously described the accumulation of extracellular ATP /AMP during chemotherapy-induced apoptosis in Jurkat human leukemia cells. In this study, we compared how different signaling pathways determine extracellular nucleotide pools in control Jurkat cells versus Jurkat lines that lack the Fas-associated death domain (FADD) or receptor-interacting protein kinase 1 (RIP1) cell death regulatory proteins. Tumor necrosis factor- α induced extrinsic apoptosis in control Jurkat cells and necroptosis in FADD-deficient cells; treatment of both lines with chemotherapeutic drugs elicited similar intrinsic apoptosis. Robust extracellular ATP/AMP accumulation was observed in the FADD-deficient cells during necroptosis, but not during apoptotic activation of Panx1 channels. Accumulation of extracellular ATP/AMP was similarly absent in RIP1-deficient Jurkat cells during apoptotic responses to chemotherapeutic agents. Apoptotic activation triggered equivalent proteolytic gating of Panx1 channels in all three Jurkat cell lines. The differences in extracellular ATP/AMP accumulation correlated with cell-line-specific expression of ectonucleotidases that metabolized the released ATP/AMP. CD73 mRNA, and α β -methylene-ADP-inhibitable ecto-AMPase activity were elevated in the FADD-deficient cells. In contrast, the RIP1-deficient cells were defined by increased expression of tartrate-sensitive prostatic acid phosphatase as a broadly acting ectonucleotidase. Thus, extracellular nucleotide accumulation during regulated tumor cell death involves interplay between ATP/AMP efflux pathways and different cell-autonomous ectonucleotidases. Differential expression of particular ectonucleotidases in tumor cell variants will determine whether chemotherapy-induced activation of Panx1 channels

  19. Crystal structure of the Haemophilus influenzae Hap adhesin reveals an intercellular oligomerization mechanism for bacterial aggregation

    Science.gov (United States)

    Meng, Guoyu; Spahich, Nicole; Kenjale, Roma; Waksman, Gabriel; St Geme, Joseph W

    2011-01-01

    Bacterial biofilms are complex microbial communities that are common in nature and are being recognized increasingly as an important determinant of bacterial virulence. However, the structural determinants of bacterial aggregation and eventual biofilm formation have been poorly defined. In Gram-negative bacteria, a major subgroup of extracellular proteins called self-associating autotransporters (SAATs) can mediate cell–cell adhesion and facilitate biofilm formation. In this study, we used the Haemophilus influenzae Hap autotransporter as a prototype SAAT to understand how bacteria associate with each other. The crystal structure of the H. influenzae HapS passenger domain (harbouring the SAAT domain) was determined to 2.2 Å by X-ray crystallography, revealing an unprecedented intercellular oligomerization mechanism for cell–cell interaction. The C-terminal SAAT domain folds into a triangular-prism-like structure that can mediate Hap–Hap dimerization and higher degrees of multimerization through its F1–F2 edge and F2 face. The intercellular multimerization can give rise to massive buried surfaces that are required for overcoming the repulsive force between cells, leading to bacterial cell–cell interaction and formation of complex microcolonies. PMID:21841773

  20. Death Cafe.

    Science.gov (United States)

    Miles, Lizzy; Corr, Charles A

    2017-06-01

    This article explains the meaning of the phrase Death Cafe and describes what typically occurs at a Death Cafe gathering. The article traces the history of the Death Cafe movement, explores some reasons why people take part in a Death Cafe gathering, and gives examples of what individuals think they might derive from their participation. In addition, this article notes similarities between the Death Cafe movement and three other developments in the field of death, dying, and bereavement. Finally, this article identifies two provisional lessons that can be drawn from Death Cafe gatherings and the Death Cafe movement itself.

  1. Core-6 fucose and the oligomerization of the 1918 pandemic influenza viral neuraminidase

    International Nuclear Information System (INIS)

    Wu, Zhengliang L.; Zhou, Hui; Ethen, Cheryl M.; Reinhold, Vernon N.

    2016-01-01

    The 1918 H1N1 influenza virus was responsible for one of the most deadly pandemics in human history. Yet to date, the structure component responsible for its virulence is still a mystery. In order to search for such a component, the neuraminidase (NA) antigen of the virus was expressed, which led to the discovery of an active form (tetramer) and an inactive form (dimer and monomer) of the protein due to different glycosylation. In this report, the N-glycans from both forms were released and characterized by mass spectrometry. It was found that the glycans from the active form had 26% core-6 fucosylated, while the glycans from the inactive form had 82% core-6 fucosylated. Even more surprisingly, the stalk region of the active form was almost completely devoid of core-6-linked fucose. These findings were further supported by the results obtained from in vitro incorporation of azido fucose and "3H-labeled fucose using core-6 fucosyltransferase, FUT8. In addition, the incorporation of fucose did not change the enzymatic activity of the active form, implying that core-6 fucose is not directly involved in the enzymatic activity. It is postulated that core-6 fucose prohibits the oligomerization and subsequent activation of the enzyme. - Graphical abstract: Proposed mechanism for how core-fucose prohibits the tetramerization of the 1918 pandemic viral neuraminidase. Only the cross section of the stalk region with two N-linked glycans are depicted for clarity. (A) Carbohydrate–carbohydrate interaction on non-fucosylated monomer allows tetramerization. (B) Core-fucosylation disrupts the interaction and prevents the tetramerization. - Highlights: • Expressed 1918 pandemic influenza viral neuraminidase has inactive and active forms. • The inactive form contains high level of core-6 fucose, while the active form lacks such modification. • Core fucose could interfere the oligomerization of the neuraminidase and thus its activation. • This discovery may explain why

  2. Core-6 fucose and the oligomerization of the 1918 pandemic influenza viral neuraminidase

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhengliang L., E-mail: Leon.wu@bio-techne.com [Bio-Techne Inc., 614 McKinley Place NE, Minneapolis, MN 55413 (United States); Zhou, Hui [Gregg Hall, UNH Glycomics Center, University of New Hampshire (United States); Ethen, Cheryl M. [Bio-Techne Inc., 614 McKinley Place NE, Minneapolis, MN 55413 (United States); Reinhold, Vernon N., E-mail: Vernon.Reinhold@unh.edu [Gregg Hall, UNH Glycomics Center, University of New Hampshire (United States)

    2016-04-29

    The 1918 H1N1 influenza virus was responsible for one of the most deadly pandemics in human history. Yet to date, the structure component responsible for its virulence is still a mystery. In order to search for such a component, the neuraminidase (NA) antigen of the virus was expressed, which led to the discovery of an active form (tetramer) and an inactive form (dimer and monomer) of the protein due to different glycosylation. In this report, the N-glycans from both forms were released and characterized by mass spectrometry. It was found that the glycans from the active form had 26% core-6 fucosylated, while the glycans from the inactive form had 82% core-6 fucosylated. Even more surprisingly, the stalk region of the active form was almost completely devoid of core-6-linked fucose. These findings were further supported by the results obtained from in vitro incorporation of azido fucose and {sup 3}H-labeled fucose using core-6 fucosyltransferase, FUT8. In addition, the incorporation of fucose did not change the enzymatic activity of the active form, implying that core-6 fucose is not directly involved in the enzymatic activity. It is postulated that core-6 fucose prohibits the oligomerization and subsequent activation of the enzyme. - Graphical abstract: Proposed mechanism for how core-fucose prohibits the tetramerization of the 1918 pandemic viral neuraminidase. Only the cross section of the stalk region with two N-linked glycans are depicted for clarity. (A) Carbohydrate–carbohydrate interaction on non-fucosylated monomer allows tetramerization. (B) Core-fucosylation disrupts the interaction and prevents the tetramerization. - Highlights: • Expressed 1918 pandemic influenza viral neuraminidase has inactive and active forms. • The inactive form contains high level of core-6 fucose, while the active form lacks such modification. • Core fucose could interfere the oligomerization of the neuraminidase and thus its activation. • This discovery may explain

  3. Inhibition of Fas-associated death domain-containing protein (FADD protects against myocardial ischemia/reperfusion injury in a heart failure mouse model.

    Directory of Open Access Journals (Sweden)

    Qian Fan

    Full Text Available As technological interventions treating acute myocardial infarction (MI improve, post-ischemic heart failure increasingly threatens patient health. The aim of the current study was to test whether FADD could be a potential target of gene therapy in the treatment of heart failure.Cardiomyocyte-specific FADD knockout mice along with non-transgenic littermates (NLC were subjected to 30 minutes myocardial ischemia followed by 7 days of reperfusion or 6 weeks of permanent myocardial ischemia via the ligation of left main descending coronary artery. Cardiac function were evaluated by echocardiography and left ventricular (LV catheterization and cardiomyocyte death was measured by Evans blue-TTC staining, TUNEL staining, and caspase-3, -8, and -9 activities. In vitro, H9C2 cells transfected with ether scramble siRNA or FADD siRNA were stressed with chelerythrin for 30 min and cleaved caspase-3 was assessed.FADD expression was significantly decreased in FADD knockout mice compared to NLC. Ischemia/reperfusion (I/R upregulated FADD expression in NLC mice, but not in FADD knockout mice at the early time. FADD deletion significantly attenuated I/R-induced cardiac dysfunction, decreased myocardial necrosis, and inhibited cardiomyocyte apoptosis. Furthermore, in 6 weeks long term permanent ischemia model, FADD deletion significantly reduced the infarct size (from 41.20 ± 3.90% in NLC to 26.83 ± 4.17% in FADD deletion, attenuated myocardial remodeling, improved cardiac function and improved survival. In vitro, FADD knockdown significantly reduced chelerythrin-induced the level of cleaved caspase-3.Taken together, our results suggest FADD plays a critical role in post-ischemic heart failure. Inhibition of FADD retards heart failure progression. Our data supports the further investigation of FADD as a potential target for genetic manipulation in the treatment of heart failure.

  4. Selective binding and oligomerization of the murine granulocyte colony-stimulating factor receptor by a low molecular weight, nonpeptidyl ligand.

    Science.gov (United States)

    Doyle, Michael L; Tian, Shin-Shay; Miller, Stephen G; Kessler, Linda; Baker, Audrey E; Brigham-Burke, Michael R; Dillon, Susan B; Duffy, Kevin J; Keenan, Richard M; Lehr, Ruth; Rosen, Jon; Schneeweis, Lumelle A; Trill, John; Young, Peter R; Luengo, Juan I; Lamb, Peter

    2003-03-14

    Granulocyte colony-stimulating factor regulates neutrophil production by binding to a specific receptor, the granulocyte colony-stimulating factor receptor, expressed on cells of the granulocytic lineage. Recombinant forms of granulocyte colony-stimulating factor are used clinically to treat neutropenias. As part of an effort to develop granulocyte colony-stimulating factor mimics with the potential for oral bioavailability, we previously identified a nonpeptidyl small molecule (SB-247464) that selectively activates murine granulocyte colony-stimulating factor signal transduction pathways and promotes neutrophil formation in vivo. To elucidate the mechanism of action of SB-247464, a series of cell-based and biochemical assays were performed. The activity of SB-247464 is strictly dependent on the presence of zinc ions. Titration microcalorimetry experiments using a soluble murine granulocyte colony-stimulating factor receptor construct show that SB-247464 binds to the extracellular domain of the receptor in a zinc ion-dependent manner. Analytical ultracentrifugation studies demonstrate that SB-247464 induces self-association of the N-terminal three-domain fragment in a manner that is consistent with dimerization. SB-247464 induces internalization of granulocyte colony-stimulating factor receptor on intact cells, consistent with a mechanism involving receptor oligomerization. These data show that small nonpeptidyl compounds are capable of selectively binding and inducing productive oligomerization of cytokine receptors.

  5. Crystalline structure of pulverized dental calculus induces cell death in oral epithelial cells.

    Science.gov (United States)

    Ziauddin, S M; Yoshimura, A; Montenegro Raudales, J L; Ozaki, Y; Higuchi, K; Ukai, T; Kaneko, T; Miyazaki, T; Latz, E; Hara, Y

    2018-06-01

    Dental calculus is a mineralized deposit attached to the tooth surface. We have shown that cellular uptake of dental calculus triggers nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation, leading to the processing of the interleukin-1β precursor into its mature form in mouse and human phagocytes. The activation of the NLRP3 inflammasome also induced a lytic form of programmed cell death, pyroptosis, in these cells. However, the effects of dental calculus on other cell types in periodontal tissue have not been investigated. The aim of this study was to determine whether dental calculus can induce cell death in oral epithelial cells. HSC-2 human oral squamous carcinoma cells, HOMK107 human primary oral epithelial cells and immortalized mouse macrophages were exposed to dental calculus or 1 of its components, hydroxyapatite crystals. For inhibition assays, the cells were exposed to dental calculus in the presence or absence of cytochalasin D (endocytosis inhibitor), z-YVAD-fmk (caspase-1 inhibitor) or glyburide (NLRP3 inflammasome inhibitor). Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) release and staining with propidium iodide. Tumor necrosis factor-α production was quantified by enzyme-linked immunosorbent assay. Oral epithelial barrier function was examined by permeability assay. Dental calculus induced cell death in HSC-2 cells, as judged by LDH release and propidium iodide staining. Dental calculus also induced LDH release from HOMK107 cells. Following heat treatment, dental calculus lost its capacity to induce tumor necrosis factor-α in mouse macrophages, but could induce LDH release in HSC-2 cells, indicating a major role of inorganic components in cell death. Hydroxyapatite crystals also induced cell death in both HSC-2 and HOMK107 cells, as judged by LDH release, indicating the capacity of crystal particles to induce cell death. Cell death induced by dental

  6. Domains and domain loss

    DEFF Research Database (Denmark)

    Haberland, Hartmut

    2005-01-01

    politicians and in the media, especially in the discussion whether some languages undergo ‘domain loss’ vis-à-vis powerful international languages like English. An objection that has been raised here is that domains, as originally conceived, are parameters of language choice and not properties of languages...

  7. Structure of the caspase-recruitment domain from a zebrafish guanylate-binding protein

    International Nuclear Information System (INIS)

    Jin, Tengchuan; Huang, Mo; Smith, Patrick; Jiang, Jiansheng; Xiao, T. Sam

    2013-01-01

    The crystal structure of the first zebrafish caspase-recruitment domain at 1.47 Å resolution illustrates a six-helix bundle fold similar to that of the human NLRP1 CARD. The caspase-recruitment domain (CARD) mediates homotypic protein–protein interactions that assemble large oligomeric signaling complexes such as the inflammasomes during innate immune responses. Structural studies of the mammalian CARDs demonstrate that their six-helix bundle folds belong to the death-domain superfamily, whereas such studies have not been reported for other organisms. Here, the zebrafish interferon-induced guanylate-binding protein 1 (zIGBP1) was identified that contains an N-terminal GTPase domain and a helical domain typical of the mammalian guanylate-binding proteins, followed by a FIIND domain and a C-terminal CARD similar to the mammalian inflammasome proteins NLRP1 and CARD8. The structure of the zIGBP1 CARD as a fusion with maltose-binding protein was determined at 1.47 Å resolution. This revealed a six-helix bundle fold similar to the NLRP1 CARD structure with the bent α1 helix typical of all known CARD structures. The zIGBP1 CARD surface contains a positively charged patch near its α1 and α4 helices and a negatively charged patch near its α2, α3 and α5 helices, which may mediate its interaction with partner domains. Further studies using binding assays and other analyses will be required in order to address the physiological function(s) of this zebrafish protein

  8. MAK33 antibody light chain amyloid fibrils are similar to oligomeric precursors.

    Directory of Open Access Journals (Sweden)

    Manuel Hora

    Full Text Available Little structural information is available so far on amyloid fibrils consisting of immunoglobulin light chains. It is not understood which features of the primary sequence of the protein result in fibril formation. We report here MAS solid-state NMR studies to identify the structured core of κ-type variable domain light chain fibrils. The core contains residues of the CDR2 and the β-strands D, E, F and G of the native immunoglobulin fold. The assigned core region of the fibril is distinct in comparison to the core identified in a previous solid-state NMR study on AL-09 by Piehl at. al, suggesting that VL fibrils can adopt different topologies. In addition, we investigated a soluble oligomeric intermediate state, previously termed the alternatively folded state (AFS, using NMR and FTIR spectroscopy. The NMR oligomer spectra display a high degree of similarity when compared to the fibril spectra, indicating a high structural similarity of the two aggregation states. Based on comparison to the native state NMR chemical shifts, we suggest that fibril formation via domain-swapping seems unlikely. Moreover, we used our results to test the quality of different amyloid prediction algorithms.

  9. The role of Vif oligomerization and RNA chaperone activity in HIV-1 replication.

    Science.gov (United States)

    Batisse, Julien; Guerrero, Santiago; Bernacchi, Serena; Sleiman, Dona; Gabus, Caroline; Darlix, Jean-Luc; Marquet, Roland; Tisné, Carine; Paillart, Jean-Christophe

    2012-11-01

    The viral infectivity factor (Vif) is essential for the productive infection and dissemination of HIV-1 in non-permissive cells that involve most natural HIV-1 target cells. Vif counteracts the packaging of two cellular cytidine deaminases named APOBEC3G (A3G) and A3F by diverse mechanisms including the recruitment of an E3 ubiquitin ligase complex and the proteasomal degradation of A3G/A3F, the inhibition of A3G mRNA translation or by a direct competition mechanism. In addition, Vif appears to be an active partner of the late steps of viral replication by participating in virus assembly and Gag processing, thus regulating the final stage of virion formation notably genomic RNA dimerization and by inhibiting the initiation of reverse transcription. Vif is a small pleiotropic protein with multiple domains, and recent studies highlighted the importance of Vif conformation and flexibility in counteracting A3G and in binding RNA. In this review, we will focus on the oligomerization and RNA chaperone properties of Vif and show that the intrinsic disordered nature of some Vif domains could play an important role in virus assembly and replication. Experimental evidence demonstrating the RNA chaperone activity of Vif will be presented. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Oligomerization of G protein-coupled receptors: computational methods.

    Science.gov (United States)

    Selent, J; Kaczor, A A

    2011-01-01

    Recent research has unveiled the complexity of mechanisms involved in G protein-coupled receptor (GPCR) functioning in which receptor dimerization/oligomerization may play an important role. Although the first high-resolution X-ray structure for a likely functional chemokine receptor dimer has been deposited in the Protein Data Bank, the interactions and mechanisms of dimer formation are not yet fully understood. In this respect, computational methods play a key role for predicting accurate GPCR complexes. This review outlines computational approaches focusing on sequence- and structure-based methodologies as well as discusses their advantages and limitations. Sequence-based approaches that search for possible protein-protein interfaces in GPCR complexes have been applied with success in several studies, but did not yield always consistent results. Structure-based methodologies are a potent complement to sequence-based approaches. For instance, protein-protein docking is a valuable method especially when guided by experimental constraints. Some disadvantages like limited receptor flexibility and non-consideration of the membrane environment have to be taken into account. Molecular dynamics simulation can overcome these drawbacks giving a detailed description of conformational changes in a native-like membrane. Successful prediction of GPCR complexes using computational approaches combined with experimental efforts may help to understand the role of dimeric/oligomeric GPCR complexes for fine-tuning receptor signaling. Moreover, since such GPCR complexes have attracted interest as potential drug target for diverse diseases, unveiling molecular determinants of dimerization/oligomerization can provide important implications for drug discovery.

  11. Deliberating death.

    Science.gov (United States)

    Landes, Scott D

    2010-01-01

    Utilizing a particular case study of a woman attempting to come to terms with her death, this article explores the difficult metaphors of death present within the Christian tradition. Tracing a Christian understanding of death back to the work of Augustine, the case study is utilized to highlight the difficulties presented by past and present theology embracing ideas of punishment within death. Following the trajectory of the case study, alternative understandings of death present in recent Christian theology and within Native American spirituality are presented in an attempt to find room for a fuller meaning of death post-reconciliation, but premortem.

  12. Oligomerization of Bacillus subtilis DesR is required for fine tuning regulation of membrane fluidity.

    Science.gov (United States)

    Najle, Sebastián R; Inda, María E; de Mendoza, Diego; Cybulski, Larisa E

    2009-10-01

    The DesK-DesR two-component system regulates the order of membrane lipids in the bacterium Bacillus subtilis by controlling the expression of the des gene coding for the delta 5-acyl-lipid desaturase. To activate des transcription, the membrane-bound histidine kinase DesK phosphorylates the response regulator DesR. This covalent modification of the regulatory domain of dimeric DesR promotes, in a cooperative fashion, the hierarchical occupation of two adjacent, non-identical, DesR-P binding sites, so that there is a shift in the equilibrium toward the tetrameric active form of the response regulator. However, the mechanism of regulation of DesR activity by phosphorylation and oligomerization is not well understood. We employed deletion analysis and reporter fusions to study the role of the N-terminal domain on DesR activity. In addition, electromobility shift assays were used to analyze the binding capacity of the transcription factor to deletion mutants of the des promoter. We show that DesR lacking the N-terminal domain is still able to bind to the des promoter. We also demonstrate that if the RA site is moved closer to the -35 region of Pdes, the adjacent site RB is dispensable for activation. Our results indicate that the unphosphorylated regulatory domain of DesR obstructs the access of the recognition helix of DesR to its DNA target. In addition, we present evidence showing that RB is physiologically relevant to control the activation of the des gene when the levels of DesR-P reach a critical threshold.

  13. Polyhedral Oligomeric Silsesquioxane (POSS)-Containing Polymer Nanocomposites

    Science.gov (United States)

    Ayandele, Ebunoluwa; Sarkar, Biswajit; Alexandridis, Paschalis

    2012-01-01

    Hybrid materials with superior structural and functional properties can be obtained by incorporating nanofillers into polymer matrices. Polyhedral oligomeric silsesquioxane (POSS) nanoparticles have attracted much attention recently due to their nanometer size, the ease of which these particles can be incorporated into polymeric materials and the unique capability to reinforce polymers. We review here the state of POSS-containing polymer nanocomposites. We discuss the influence of the incorporation of POSS into polymer matrices via chemical cross-linking or physical blending on the structure of nanocomposites, as affected by surface functional groups, and the POSS concentration. PMID:28348318

  14. Mechanism of the electrochemical oligomerization of thionaphteneindole: a spectroscopic study

    Science.gov (United States)

    Poggi, Gabriella; Casalbore Miceli, Giuseppe; Beggiato, Giancarlo; Emmi, Salvatore S.

    1997-10-01

    The UV, visible and NIR spectra recorded during electrolysis of TNI in CH 2Cl 2 have been studied as a function of electrolysis time and of the quantity of charge exchanged. Among the oligomeric species that might be responsible for the behaviour observed, particular attention has been devoted to dimers of TNI characterized by different charges, presence of unpaired electrons, and deprotonation of the amino hydrogens. A sample of these species has been described theoretically by means of the PM3 semiempirical hamiltonian and their spectra have been computed giving results in reasonable agreement with the observed transitions.

  15. Cartilage oligomeric matrix protein specific antibodies are pathogenic

    DEFF Research Database (Denmark)

    Geng, Hui; Nandakumar, Kutty Selva; Pramhed, Anna

    2012-01-01

    -specific monoclonal antibodies (mAbs). METHODS: B cell immunodominant regions on the COMP molecule were measured with a novel enzyme-linked immunosorbent assay using mammalian expressed full-length mouse COMP as well as a panel of recombinant mouse COMP fragments. 18 mAbs specific to COMP were generated......ABSTRACT: INTRODUCTION: Cartilage oligomeric matrix protein (COMP) is a major non-collagenous component of cartilage. Earlier, we developed a new mouse model for rheumatoid arthritis using COMP. This study was undertaken to investigate the epitope specificity and immunopathogenicity of COMP...

  16. Receptor Oligomerization as a Process Modulating Cellular Semiotics

    DEFF Research Database (Denmark)

    Giorgi, Franco; Bruni, Luis Emilio; Maggio, Roberto

    2010-01-01

    be another level of quality control that may help maintaining GPCRs rather stable throughout evolution. We propose here receptor oligomerization to be a basic molecular mechanism controlling GPCRs redundancy in many different cell types, and the plasma membrane as the first hierarchical cell structure...... at which selective categorical sensing may occur. Categorical sensing can be seen as the cellular capacity for identifying and ordering complex patterns of mixed signals out of a contextual matrix, i.e., the recognition of meaningful patterns out of ubiquitous signals. In this context, redundancy...

  17. Redefining Death

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The results of 20 years of research on brain death will be released to the public, the Chinese Ministry of Health reported in early April. A special ministry team has drafted the criteria for brain death in Criteria for the Diagnosis of Brain Death in Adults (Revised Edition) and Technical Specifications for the Diagnosis

  18. Zn(2+) site engineering at the oligomeric interface of the dopamine transporter

    DEFF Research Database (Denmark)

    Norgaard-Nielsen, Kristine; Norregaard, Lene; Hastrup, Hanne

    2002-01-01

    Increasing evidence suggests that Na(+)/Cl(-)-dependent neurotransmitter transporters exist as homo-oligomeric proteins. However, the functional implication of this oligomerization remains unclear. Here we demonstrate the engineering of a Zn(2+) binding site at the predicted dimeric interface...

  19. Biophysical investigation of type A PutAs reveals a conserved core oligomeric structure

    Energy Technology Data Exchange (ETDEWEB)

    Korasick, David A. [Department of Biochemistry, University of Missouri, Columbia MO USA; Singh, Harkewal [Department of Chemistry, University of Missouri, Columbia MO USA; Pemberton, Travis A. [Department of Chemistry, University of Missouri, Columbia MO USA; Luo, Min [Department of Chemistry, University of Missouri, Columbia MO USA; Dhatwalia, Richa [Department of Chemistry, University of Missouri, Columbia MO USA; Tanner, John J. [Department of Biochemistry, University of Missouri, Columbia MO USA; Department of Chemistry, University of Missouri, Columbia MO USA

    2017-08-01

    Many enzymes form homooligomers, yet the functional significance of self-association is seldom obvious. Herein, we examine the connection between oligomerization and catalytic function for proline utilization A (PutA) enzymes. PutAs are bifunctional enzymes that catalyze both reactions of proline catabolism. Type A PutAs are the smallest members of the family, possessing a minimal domain architecture consisting of N-terminal proline dehydrogenase and C-terminal l-glutamate-γ-semialdehyde dehydrogenase modules. Type A PutAs form domain-swapped dimers, and in one case (Bradyrhizobium japonicum PutA), two of the dimers assemble into a ring-shaped tetramer. Whereas the dimer has a clear role in substrate channeling, the functional significance of the tetramer is unknown. To address this question, we performed structural studies of four-type A PutAs from two clades of the PutA tree. The crystal structure of Bdellovibrio bacteriovorus PutA covalently inactivated by N-propargylglycine revealed a fold and substrate-channeling tunnel similar to other PutAs. Small-angle X-ray scattering (SAXS) and analytical ultracentrifugation indicated that Bdellovibrio PutA is dimeric in solution, in contrast to the prediction from crystal packing of a stable tetrameric assembly. SAXS studies of two other type A PutAs from separate clades also suggested that the dimer predominates in solution. To assess whether the tetramer of B. japonicum PutA is necessary for catalytic function, a hot spot disruption mutant that cleanly produces dimeric protein was generated. The dimeric variant exhibited kinetic parameters similar to the wild-type enzyme. These results implicate the domain-swapped dimer as the core structural and functional unit of type A PutAs.

  20. RNAi reduces expression and intracellular retention of mutant cartilage oligomeric matrix protein.

    Directory of Open Access Journals (Sweden)

    Karen L Posey

    2010-04-01

    Full Text Available Mutations in cartilage oligomeric matrix protein (COMP, a large extracellular glycoprotein expressed in musculoskeletal tissues, cause two skeletal dysplasias, pseudoachondroplasia and multiple epiphyseal dysplasia. These mutations lead to massive intracellular retention of COMP, chondrocyte death and loss of growth plate chondrocytes that are necessary for linear growth. In contrast, COMP null mice have only minor growth plate abnormalities, normal growth and longevity. This suggests that reducing mutant and wild-type COMP expression in chondrocytes may prevent the toxic cellular phenotype causing the skeletal dysplasias. We tested this hypothesis using RNA interference to reduce steady state levels of COMP mRNA. A panel of shRNAs directed against COMP was tested. One shRNA (3B reduced endogenous and recombinant COMP mRNA dramatically, regardless of expression levels. The activity of the shRNA against COMP mRNA was maintained for up to 10 weeks. We also demonstrate that this treatment reduced ER stress. Moreover, we show that reducing steady state levels of COMP mRNA alleviates intracellular retention of other extracellular matrix proteins associated with the pseudoachondroplasia cellular pathology. These findings are a proof of principle and the foundation for the development of a therapeutic intervention based on reduction of COMP expression.

  1. Role for nucleotide-binding oligomerization domain 1 (NOD1) in pericyte-mediated vascular inflammation

    DEFF Research Database (Denmark)

    Navarro, Rocio; Delgado-Wicke, Pablo; Nuñez-Prado, Natalia

    2016-01-01

    We have recently described the response of human brain pericytes to lipopolysaccharide (LPS) through TLR4. However, gram-negative pathogen-associated molecular patterns include not only LPS but also peptidoglycan (PGN). Given that the presence of co-purified PGN in the LPS preparation previously ...

  2. N-terminal aliphatic residues dictate the structure, stability, assembly, and small molecule binding of the coiled-coil region of cartilage oligomeric matrix protein.

    Science.gov (United States)

    Gunasekar, Susheel K; Asnani, Mukta; Limbad, Chandani; Haghpanah, Jennifer S; Hom, Wendy; Barra, Hanna; Nanda, Soumya; Lu, Min; Montclare, Jin Kim

    2009-09-15

    The coiled-coil domain of cartilage oligomeric matrix protein (COMPcc) assembles into a homopentamer that naturally recognizes the small molecule 1,25-dihydroxyvitamin D(3) (vit D). To identify the residues critical for the structure, stability, oligomerization, and binding to vit D as well as two other small molecules, all-trans-retinol (ATR) and curcumin (CCM), here we perform an alanine scanning mutagenesis study. Ten residues lining the hydrophobic pocket of COMPcc were mutated into alanine; of the mutated residues, the N-terminal aliphatic residues L37, L44, V47, and L51 are responsible for maintaining the structure and function. Furthermore, two polar residues, T40 and Q54, within the N-terminal region when converted into alanine improve the alpha-helical structure, stability, and self-assembly behavior. Helical stability, oligomerization, and binding appear to be linked in a manner in which mutations that abolish helical structure and assembly bind poorly to vit D, ATR, and CCM. These results provide not only insight into COMPcc and its functional role but also useful guidelines for the design of stable, pentameric coiled-coils capable of selectively storing and delivering various small molecules.

  3. Synaptic transmission block by presynaptic injection of oligomeric amyloid beta

    Science.gov (United States)

    Moreno, Herman; Yu, Eunah; Pigino, Gustavo; Hernandez, Alejandro I.; Kim, Natalia; Moreira, Jorge E.; Sugimori, Mutsuyuki; Llinás, Rodolfo R.

    2009-01-01

    Early Alzheimer's disease (AD) pathophysiology is characterized by synaptic changes induced by degradation products of amyloid precursor protein (APP). The exact mechanisms of such modulation are unknown. Here, we report that nanomolar concentrations of intraaxonal oligomeric (o)Aβ42, but not oAβ40 or extracellular oAβ42, acutely inhibited synaptic transmission at the squid giant synapse. Further characterization of this phenotype demonstrated that presynaptic calcium currents were unaffected. However, electron microscopy experiments revealed diminished docked synaptic vesicles in oAβ42-microinjected terminals, without affecting clathrin-coated vesicles. The molecular events of this modulation involved casein kinase 2 and the synaptic vesicle rapid endocytosis pathway. These findings open the possibility of a new therapeutic target aimed at ameliorating synaptic dysfunction in AD. PMID:19304802

  4. Fluorescence reporters for Hfq oligomerization and RNA annealing

    Science.gov (United States)

    Panja, Subrata; Woodson, Sarah A.

    2015-01-01

    Fluorescence spectroscopy is a sensitive technique for detecting protein-protein, protein-RNA and RNA-RNA interactions, requiring only nanomolar concentrations of labeled components. Fluorescence anisotropy provides information about the assembly of multi-subunit proteins, while molecular beacons provide a sensitive and quantitative reporter for base pairing between complementary RNAs. Here we present a detailed protocol for labeling Hfq protein with cyanine 3-maleimide and dansyl chloride to study the protein oligomerization and RNA binding by semi-native polyacrylamide gel electrophoresis (PAGE) and fluorescence anisotropy. We also present a detailed protocol for measuring the rate of annealing between a molecular beacon and a target RNA in the presence of Hfq using a stopped-flow spectrometer. PMID:25579597

  5. Effects of Glycine, Water, Ammonia, and Ammonium Bicarbonate on the Oligomerization of Methionine

    Science.gov (United States)

    Huang, Rui; Furukawa, Yoshihiro; Otake, Tsubasa; Kakegawa, Takeshi

    2017-06-01

    The abiotic oligomerization of amino acids may have created primordial, protein-like biological catalysts on the early Earth. Previous studies have proposed and evaluated the potential of diagenesis for the amino acid oligomerization, simulating the formation of peptides that include glycine, alanine, and valine, separately. However, whether such conditions can promote the formation of peptides composed of multiple amino acids remains unclear. Furthermore, the chemistry of pore water in sediments should affect the oligomerization and degradation of amino acids and oligomers, but these effects have not been studied extensively. In this study, we investigated the effects of water, ammonia, ammonium bicarbonate, pH, and glycine on the oligomerization and degradation of methionine under high pressure (150 MPa) and high temperature conditions (175 °C) for 96 h. Methionine is more difficult to oligomerize than glycine and methionine dimer was formed in the incubation of dry powder of methionine. Methionine oligomers as long as trimers, as well as methionylglycine and glycylmethionine, were formed under every condition with these additional compounds. Among the compounds tested, the oligomerization reaction rate was accelerated by the presence of water and by an increase in pH. Ammonia also increased the oligomerization rate but consumed methionine by side reactions and resulted in the rapid degradation of methionine and its peptides. Similarly, glycine accelerated the oligomerization rate of methionine and the degradation of methionine, producing water, ammonia, and bicarbonate through its decomposition. With Gly, heterogeneous dimers (methionylglycine and glycylmethionine) were formed in greater amounts than with other additional compounds although smaller amount of these heterogeneous dimers were formed with other additional compounds. These results suggest that accelerated reaction rates induced by water and co-existing reactive compounds promote the oligomerization

  6. Structure of the large terminase from a hyperthermophilic virus reveals a unique mechanism for oligomerization and ATP hydrolysis.

    Science.gov (United States)

    Xu, Rui-Gang; Jenkins, Huw T; Antson, Alfred A; Greive, Sandra J

    2017-12-15

    The crystal structure of the large terminase from the Geobacillus stearothermophilus bacteriophage D6E shows a unique relative orientation of the N-terminal adenosine triphosphatase (ATPase) and C-terminal nuclease domains. This monomeric 'initiation' state with the two domains 'locked' together is stabilized via a conserved C-terminal arm, which may interact with the portal protein during motor assembly, as predicted for several bacteriophages. Further work supports the formation of an active oligomeric state: (i) AUC data demonstrate the presence of oligomers; (ii) mutational analysis reveals a trans-arginine finger, R158, indispensable for ATP hydrolysis; (iii) the location of this arginine is conserved with the HerA/FtsK ATPase superfamily; (iv) a molecular docking model of the pentamer is compatible with the location of the identified arginine finger. However, this pentameric model is structurally incompatible with the monomeric 'initiation' state and is supported by the observed increase in kcat of ATP hydrolysis, from 7.8 ± 0.1 min-1 to 457.7 ± 9.2 min-1 upon removal of the C-terminal nuclease domain. Taken together, these structural, biophysical and biochemical data suggest a model where transition from the 'initiation' state into a catalytically competent pentameric state, is accompanied by substantial domain rearrangements, triggered by the removal of the C-terminal arm from the ATPase active site. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  7. Thermal Degradation Mechanism of a Thermostable Polyester Stabilized with an Open-Cage Oligomeric Silsesquioxane

    Directory of Open Access Journals (Sweden)

    Yolanda Bautista

    2017-12-01

    Full Text Available A polyester composite was prepared through the polymerization of an unsaturated ester resin with styrene and an open-cage oligomeric silsesquioxane with methacrylate groups. The effect of the open-cage oligomeric silsesquioxane on the thermal stability of the thermostable polyester was studied using both thermogravimetric analysis and differential thermal analysis. The results showed that the methacryl oligomeric silsesquioxane improved the thermal stability of the polyester. The decomposition mechanism of the polyester/oligomer silsesquioxane composite was proposed by Fourier transform infrared spectroscopy (FTIR analysis of the volatiles.

  8. Oligomeric protein structure networks: insights into protein-protein interactions

    Directory of Open Access Journals (Sweden)

    Brinda KV

    2005-12-01

    Full Text Available Abstract Background Protein-protein association is essential for a variety of cellular processes and hence a large number of investigations are being carried out to understand the principles of protein-protein interactions. In this study, oligomeric protein structures are viewed from a network perspective to obtain new insights into protein association. Structure graphs of proteins have been constructed from a non-redundant set of protein oligomer crystal structures by considering amino acid residues as nodes and the edges are based on the strength of the non-covalent interactions between the residues. The analysis of such networks has been carried out in terms of amino acid clusters and hubs (highly connected residues with special emphasis to protein interfaces. Results A variety of interactions such as hydrogen bond, salt bridges, aromatic and hydrophobic interactions, which occur at the interfaces are identified in a consolidated manner as amino acid clusters at the interface, from this study. Moreover, the characterization of the highly connected hub-forming residues at the interfaces and their comparison with the hubs from the non-interface regions and the non-hubs in the interface regions show that there is a predominance of charged interactions at the interfaces. Further, strong and weak interfaces are identified on the basis of the interaction strength between amino acid residues and the sizes of the interface clusters, which also show that many protein interfaces are stronger than their monomeric protein cores. The interface strengths evaluated based on the interface clusters and hubs also correlate well with experimentally determined dissociation constants for known complexes. Finally, the interface hubs identified using the present method correlate very well with experimentally determined hotspots in the interfaces of protein complexes obtained from the Alanine Scanning Energetics database (ASEdb. A few predictions of interface hot

  9. Domain analysis

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2017-01-01

    The domain-analytic approach to knowledge organization (KO) (and to the broader field of library and information science, LIS) is outlined. The article reviews the discussions and proposals on the definition of domains, and provides an example of a domain-analytic study in the field of art studies....... Varieties of domain analysis as well as criticism and controversies are presented and discussed....

  10. Oligomerization of optineurin and its oxidative stress- or E50K mutation-driven covalent cross-linking: possible relationship with glaucoma pathology.

    Directory of Open Access Journals (Sweden)

    Jie Gao

    Full Text Available The optineurin gene, OPTN, is one of the causative genes of primary open-angle glaucoma. Although oligomerization of optineurin in cultured cells was previously observed by gel filtration analysis and blue native gel electrophoresis (BNE, little is known about the characteristics of optineurin oligomers. Here, we aimed to analyze the oligomeric state of optineurin and factors affecting oligomerization, such as environmental stimuli or mutations in OPTN. Using BNE or immunoprecipitation followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE, we demonstrated that both endogenous and transfected optineurin exist as oligomers, rather than monomers, in NIH3T3 cells. We also applied an in situ proximity ligation assay to visualize the self-interaction of optineurin in fixed HeLaS3 cells and found that the optineurin oligomers were localized diffusely in the cytoplasm. Optineurin oligomers were usually detected as a single band of a size equal to that of the optineurin monomer upon SDS-PAGE, while an additional protein band of a larger size was observed when cells were treated with H2O2. We showed that larger protein complex is optineurin oligomers by immunoprecipitation and termed it covalent optineurin oligomers. In cells expressing OPTN bearing the most common glaucoma-associated mutation, E50K, covalent oligomers were formed even without H2O2 stimulation. Antioxidants inhibited the formation of E50K-induced covalent oligomers to various degrees. A series of truncated constructs of OPTN was used to reveal that covalent oligomers may be optineurin trimers and that the ubiquitin-binding domain is essential for formation of these trimers. Our results indicated that optineurin trimers may be the basic unit of these oligomers. The oligomeric state can be affected by many factors that induce covalent bonds, such as H2O2 or E50K, as demonstrated here; this provides novel insights into the pathogenicity of E50K. Furthermore

  11. Exceptionally High Electric Double Layer Capacitances of Oligomeric Ionic Liquids.

    Science.gov (United States)

    Matsumoto, Michio; Shimizu, Sunao; Sotoike, Rina; Watanabe, Masayoshi; Iwasa, Yoshihiro; Itoh, Yoshimitsu; Aida, Takuzo

    2017-11-15

    Electric double layer (EDL) capacitors are promising as next-generation energy accumulators if their capacitances and operation voltages are both high. However, only few electrolytes can simultaneously fulfill these two requisites. Here we report that an oligomeric ionic liquid such as IL4 TFSI with four imidazolium ion units in its structure provides a wide electrochemical window of ∼5.0 V, similar to monomeric ionic liquids. Furthermore, electrochemical impedance measurements using Au working electrodes demonstrated that IL4 TFSI exhibits an exceptionally high EDL capacitance of ∼66 μF/cm 2 , which is ∼6 times as high as those of monomeric ionic liquids so far reported. We also found that an EDL-based field effect transistor (FET) using IL4 TFSI as a gate dielectric material and SrTiO 3 as a channel material displays a very sharp transfer curve with an enhanced carrier accumulation capability of ∼64 μF/cm 2 , as determined by Hall-effect measurements.

  12. Preparation of polyhedral oligomeric silsesquioxane based imprinted monolith.

    Science.gov (United States)

    Li, Fang; Chen, Xiu-Xiu; Huang, Yan-Ping; Liu, Zhao-Sheng

    2015-12-18

    Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic column with high porosity and good permeability. The imprinted monolithic column was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), naproxon (template), 4-vinylpyridine, and ethylene glycol dimethacrylate, in ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4). The influence of synthesis parameters on the retention factor and imprinting effect, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest imprinting factor on the imprinted monolithic column prepared with MA 0702 was 22, about 10 times higher than that prepared in absence of POSS. The comparisons between MIP monoliths synthesized with POSS and without POSS were made in terms of permeability, column efficiency, surface morphology and pore size distribution. In addition, thermodynamic and Van Deemter analysis were used to evaluate the POSS-based MIP monolith. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Assessing heterogeneity in oligomeric AAA+ machines.

    Science.gov (United States)

    Sysoeva, Tatyana A

    2017-03-01

    ATPases Associated with various cellular Activities (AAA+ ATPases) are molecular motors that use the energy of ATP binding and hydrolysis to remodel their target macromolecules. The majority of these ATPases form ring-shaped hexamers in which the active sites are located at the interfaces between neighboring subunits. Structural changes initiate in an active site and propagate to distant motor parts that interface and reshape the target macromolecules, thereby performing mechanical work. During the functioning cycle, the AAA+ motor transits through multiple distinct states. Ring architecture and placement of the catalytic sites at the intersubunit interfaces allow for a unique level of coordination among subunits of the motor. This in turn results in conformational differences among subunits and overall asymmetry of the motor ring as it functions. To date, a large amount of structural information has been gathered for different AAA+ motors, but even for the most characterized of them only a few structural states are known and the full mechanistic cycle cannot be yet reconstructed. Therefore, the first part of this work will provide a broad overview of what arrangements of AAA+ subunits have been structurally observed focusing on diversity of ATPase oligomeric ensembles and heterogeneity within the ensembles. The second part of this review will concentrate on methods that assess structural and functional heterogeneity among subunits of AAA+ motors, thus bringing us closer to understanding the mechanism of these fascinating molecular motors.

  14. Antibodies against alpha-synuclein reduce oligomerization in living cells.

    Directory of Open Access Journals (Sweden)

    Thomas Näsström

    Full Text Available Recent research implicates soluble aggregated forms of α-synuclein as neurotoxic species with a central role in the pathogenesis of Parkinson's disease and related disorders. The pathway by which α-synuclein aggregates is believed to follow a step-wise pattern, in which dimers and smaller oligomers are initially formed. Here, we used H4 neuroglioma cells expressing α-synuclein fused to hemi:GFP constructs to study the effects of α-synuclein monoclonal antibodies on the early stages of aggregation, as quantified by Bimolecular Fluorescence Complementation assay. Widefield and confocal microscopy revealed that cells treated for 48 h with monoclonal antibodies internalized antibodies to various degrees. C-terminal and oligomer-selective α-synuclein antibodies reduced the extent of α-synuclein dimerization/oligomerization, as indicated by decreased GFP fluorescence signal. Furthermore, ELISA measurements on lysates and conditioned media from antibody treated cells displayed lower α-synuclein levels compared to untreated cells, suggesting increased protein turnover. Taken together, our results propose that extracellular administration of monoclonal antibodies can modify or inhibit early steps in the aggregation process of α-synuclein, thus providing further support for passive immunization against diseases with α-synuclein pathology.

  15. Inside-out signaling promotes dynamic changes in the carcinoembryonic antigen-related cellular adhesion molecule 1 (CEACAM1) oligomeric state to control its cell adhesion properties.

    Science.gov (United States)

    Patel, Prerna C; Lee, Hannah S W; Ming, Aaron Y K; Rath, Arianna; Deber, Charles M; Yip, Christopher M; Rocheleau, Jonathan V; Gray-Owen, Scott D

    2013-10-11

    Cell-cell contacts are fundamental to multicellular organisms and are subject to exquisite levels of control. The carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) can engage in both cis-homophilic (parallel) oligomerization and trans-homophilic (anti-parallel) binding. In this study, we establish that the CEACAM1 transmembrane domain has a propensity to form cis-dimers via the transmembrane-embedded (432)GXXXG(436) motif and that this basal state is overcome when activated calmodulin binds to the CEACAM1 cytoplasmic domain. Although mutation of the (432)GXXXG(436) motif reduced CEACAM1 oligomerization, it did not affect surface localization of the receptor or influence CEACAM1-dependent cellular invasion by the pathogenic Neisseria. The mutation did, however, have a striking effect on CEACAM1-dependent cellular aggregation, increasing both the kinetics of cell-cell association and the size of cellular aggregates formed. CEACAM1 association with tyrosine kinase c-Src and tyrosine phosphatases SHP-1 and SHP-2 was not affected by the (432)GXXXG(436) mutation, consistent with their association with the monomeric form of wild type CEACAM1. Collectively, our results establish that a dynamic oligomer-to-monomer shift in surface-expressed CEACAM1 facilitates trans-homophilic binding and downstream effector signaling.

  16. Surviving death

    DEFF Research Database (Denmark)

    Gerstroem, Anna

    2013-01-01

    such phases. The aim of this paper is to explore how an organization’s identity is re-constructed after organizational death. Based on interviews with members of a bankrupted bank who narrate their bankruptcy experiences, the paper explores how legacy organizational identity is constructed after...... organizational death. The paper shows how members draw on their legacy organizational identity to justify their past interpretations and responses to the intensifying bankruptcy threats. Members refer to their firm belief in the bank’s solid and robust identity claim when they explain how they disregarded...

  17. Composite polymer electrolyte containing ionic liquid and functionalized polyhedral oligomeric silsesquioxanes for anhydrous PEM applications.

    Science.gov (United States)

    Subianto, Surya; Mistry, Mayur K; Choudhury, Namita Roy; Dutta, Naba K; Knott, Robert

    2009-06-01

    A new type of supported liquid membrane was made by combining an ionic liquid (IL) with a Nafion membrane reinforced with multifunctional polyhedral oligomeric silsesquioxanes (POSSs) using a layer-by-layer strategy for anhydrous proton-exchange membrane (PEM) application. The POSS was functionalized by direct sulfonation, and the sulfonated POSS (S-POSS) was incorporated into Nafion 117 membranes by the infiltration method. The resultant hybrid membrane shows strong ionic interaction between the Nafion matrix and the multifunctional POSS, resulting in increased glass transition temperature and thermal stability at very low loadings of S-POSS (1%). The presence of S-POSS has also improved the proton conductivity especially at low humidities, where it shows a marked increase due to its confinement in the ionic domains and promotes water uptake by capillary condensation. In order to achieve anhydrous conductivity, the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI) was incorporated into these membranes to provide proton conduction in the absence of water. Although the incorporation of an IL shows a plasticizing effect on the Nafion membrane, the S-POSS composite membrane with an IL shows a higher modulus at high temperatures compared to Nafion 117 and a Nafion-IL membrane, with significantly higher proton conductivity (5 mS/cm at 150 degrees C with 20% IL). This shows the ability of the multifunctional POSS and IL to work symbiotically to achieve the desirable proton conductivity and mechanical properties of such membranes by enhancing the ionic interaction within the material.

  18. Oligomerization of optically active N-(4-hydroxyphenylmandelamide in the presence of β-cyclodextrin and the minor role of chirality

    Directory of Open Access Journals (Sweden)

    Helmut Ritter

    2014-10-01

    Full Text Available The oxidative oligomerization of a chiral mandelamide derivative (N-(4-hydroxyphenylmandelamide, 1 was performed in the presence of horseradish peroxidase, laccase and N,N'-bis(salicylideneethylenediamine-iron(II to obtain chiral oligophenols 2. The low enantioselectivity of the enzymatic catalyzed asymmetric enantiomer-differentiating oligomerizations was investigated. In addition, the poor influence of cyclodextrin on the enantioselectivity of enzymatic catalyzed asymmetric enantiomer-differentiating oligomerizations was studied.

  19. Concrete domains

    OpenAIRE

    Kahn, G.; Plotkin, G.D.

    1993-01-01

    This paper introduces the theory of a particular kind of computation domains called concrete domains. The purpose of this theory is to find a satisfactory framework for the notions of coroutine computation and sequentiality of evaluation.

  20. Death cap

    DEFF Research Database (Denmark)

    Rudbæk, Torsten R; Kofoed, Pernille Bouteloup; Bove, Jeppe

    2014-01-01

    Death cap (Amanita phalloides) is commonly found and is one of the five most toxic fungi in Denmark. Toxicity is due to amatoxin, and poisoning is a serious medical condition, causing organ failure with potential fatal outcome. Acknowledgement and clarification of exposure, symptomatic and focused...

  1. "Spectacular Death"

    DEFF Research Database (Denmark)

    Jacobsen, Michael Hviid

    2016-01-01

    be labelled ‘spectacular death’ in which death, dying and mourning have increasingly become spectacles. Moreover, the author proposes that what is currently happening in contemporary Western society can be interpreted as an expression of a ‘partial re-reversal’ of ‘forbidden death’ to some...

  2. Deaths: Leading Causes for 2011.

    Science.gov (United States)

    Heron, Melonie

    2015-07-27

    This report presents final 2011 data on the 10 leading causes of death in the United States by age, sex, race, and Hispanic origin. Leading causes of infant, neonatal, and postneonatal death are also presented. This report supplements ‘‘Deaths: Final Data for 2011,’’ the National Center for Health Statistics’ annual report of final mortality statistics. Data in this report are based on information from all death certificates filed in the 50 states and the District of Columbia in 2011. Causes of death classified by the International Classification of Diseases, 10th Revision (ICD–10) are ranked according to the number of deaths assigned to rankable causes. Cause-of-death statistics are based on the underlying cause of death. In 2011, the 10 leading causes of death were, in rank order: Diseases of heart; Malignant neoplasms; Chronic lower respiratory diseases; Cerebrovascular diseases; Accidents (unintentional injuries); Alzheimer’s disease; Diabetes mellitus; Influenza and pneumonia; Nephritis, nephrotic syndrome and nephrosis; and Intentional self-harm (suicide). They accounted for 74% of all deaths occurring in the United States. Differences in the rankings are evident by age, sex, race, and Hispanic origin. Leading causes of infant death for 2011 were, in rank order: Congenital malformations, deformations and chromosomal abnormalities; Disorders related to short gestation and low birth weight, not elsewhere classified; Sudden infant death syndrome; Newborn affected by maternal complications of pregnancy; Accidents (unintentional injuries); Newborn affected by complications of placenta, cord and membranes; Bacterial sepsis of newborn; Respiratory distress of newborn; Diseases of the circulatory system; and Neonatal hemorrhage. Important variations in the leading causes of infant death are noted for the neonatal and postneonatal periods. All material appearing in this report is in the public domain and may be reproduced or copied without permission

  3. Deaths: Leading Causes for 2015.

    Science.gov (United States)

    Heron, Melonie

    2017-11-01

    Objectives-This report presents final 2015 data on the 10 leading causes of death in the United States by age, sex, race, and Hispanic origin. Leading causes of infant, neonatal, and postneonatal death are also presented. This report supplements "Deaths: Final Data for 2015," the National Center for Health Statistics' annual report of final mortality statistics. Methods-Data in this report are based on information from all death certificates filed in the 50 states and the District of Columbia in 2015. Causes of death classified by the International Classification of Diseases, Tenth Revision (ICD-10) are ranked according to the number of deaths assigned to rankable causes. Cause-of-death statistics are based on the underlying cause of death. Results-In 2015, the 10 leading causes of death were, in rank order: Diseases of heart; Malignant neoplasms; Chronic lower respiratory diseases; Accidents (unintentional injuries); Cerebrovascular diseases; Alzheimer's disease; Diabetes mellitus; Influenza and pneumonia; Nephritis, nephrotic syndrome and nephrosis; and Intentional self-harm (suicide). They accounted for 74% of all deaths occurring in the United States. Differences in the rankings are evident by age, sex, race, and Hispanic origin. Leading causes of infant death for 2015 were, in rank order: Congenital malformations, deformations and chromosomal abnormalities; Disorders related to short gestation and low birth weight, not elsewhere classified; Sudden infant death syndrome; Newborn affected by maternal complications of pregnancy; Accidents (unintentional injuries); Newborn affected by complications of placenta, cord and membranes; Bacterial sepsis of newborn; Respiratory distress of newborn; Diseases of the circulatory system; and Neonatal hemorrhage. Important variations in the leading causes of infant death are noted for the neonatal and postneonatal periods. All material appearing in this report is in the public domain and may be reproduced or copied without

  4. Deaths: Leading Causes for 2013.

    Science.gov (United States)

    Heron, Melonie

    2016-02-16

    This report presents final 2013 data on the 10 leading causes of death in the United States by age, sex, race, and Hispanic origin. Leading causes of infant, neonatal, and postneonatal death are also presented. This report supplements "Deaths: Final Data for 2013," the National Center for Health Statistics’ annual report of final mortality statistics. Data in this report are based on information from all death certificates filed in the 50 states and the District of Columbia in 2013. Causes of death classified by the International Classification of Diseases, Tenth Revision (ICD–10) are ranked according to the number of deaths assigned to rankable causes. Cause-of-death statistics are based on the underlying cause of death. In 2013, the 10 leading causes of death were, in rank order: Diseases of heart; Malignant neoplasms; Chronic lower respiratory diseases; Accidents (unintentional injuries); Cerebrovascular diseases; Alzheimer’s disease; Diabetes mellitus; Influenza and pneumonia; Nephritis, nephrotic syndrome and nephrosis; and Intentional self-harm (suicide). They accounted for 74% of all deaths occurring in the United States. Differences in the rankings are evident by age, sex, race, and Hispanic origin. Leading causes of infant death for 2013 were, in rank order: Congenital malformations, deformations and chromosomal abnormalities; Disorders related to short gestation and low birth weight, not elsewhere classified; Newborn affected by maternal complications of pregnancy; Sudden infant death syndrome; Accidents (unintentional injuries); Newborn affected by complications of placenta, cord and membranes; Bacterial sepsis of newborn; Respiratory distress of newborn; Diseases of the circulatory system; and Neonatal hemorrhage. Important variations in the leading causes of infant death are noted for the neonatal and postneonatal periods. All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as

  5. Morphology and Phase Transitions in Styrene-Butadiene-Styrene Triblock Copolymer Grafted with Isobutyl Substituted Polyhedral Oligomeric Silsesquioxanes (Postprint)

    National Research Council Canada - National Science Library

    Drazowski, Daniel B; Lee, Andre; Haddad, Timothy S

    2007-01-01

    Two symmetric triblock polystyrene-butadiene-polystyrene (SBS) copolymers with different styrene content were grafted with varying amounts of isobutyl-substituted polyhedral oligomeric silsesquioxane (POSS) molecules...

  6. Morphology and Phase Transitions in Styrene-Butadiene-Styrene Triblock Copolymer Grafted with Isobutyl Substituted Polyhedral Oligomeric Silsesquioxanes (preprint)

    National Research Council Canada - National Science Library

    Drazkowski, Daniel B; Lee, Andre; Haddad, Timothy S

    2006-01-01

    Two symmetric triblock polystyrene-butadiene-polystyrene (SBS) copolymers with different styrene content were grafted with varying amounts of isobutyl-substituted polyhedral oligomeric silsesquioxane (POSS) molecules...

  7. Domain Engineering

    Science.gov (United States)

    Bjørner, Dines

    Before software can be designed we must know its requirements. Before requirements can be expressed we must understand the domain. So it follows, from our dogma, that we must first establish precise descriptions of domains; then, from such descriptions, “derive” at least domain and interface requirements; and from those and machine requirements design the software, or, more generally, the computing systems.

  8. The neuroprotective effects of milk fat globule-EGF factor 8 against oligomeric amyloid β toxicity

    Directory of Open Access Journals (Sweden)

    Li Endong

    2012-06-01

    Full Text Available Abstract Background Phosphatidylserine receptor is a key molecule that mediates the phagocytosis of apoptotic cells. Milk fat globule-EGF factor 8 (MFG-E8 is a phosphatidylserine receptor that is expressed on various macrophage lineage cells, including microglia in the central nervous system (CNS. Targeted clearance of degenerated neurons by microglia is essential to maintain healthy neural networks. We previously showed that the CX3C chemokine fractalkine is secreted from degenerated neurons and accelerates microglial clearance of neuronal debris via inducing the release of MFG-E8. However, the mechanisms by which microglia produce MFG-E8 and the precise functions of MFG-E8 are unknown. Methods The release of MFG-E8 from microglia treated with conditioned medium from neurons exposed to neurotoxic substances, glutamate or oligomeric amyloid β (oAβ was measured by ELISA. The neuroprotective effects of MFG-E8 and MFG-E8 − induced microglial phagocytosis of oAβ were assessed by immunocytochemistry. The effects of MFG-E8 on the production of the anti-oxidative enzyme hemeoxygenase-1 (HO-1 were determined by ELISA and immunocytochemisty. Results MFG-E8 was induced in microglia treated with conditioned medium from neurons that had been exposed to neurotoxicants, glutamate or oAβ. MFG-E8 significantly attenuated oAβ-induced neuronal cell death in a primary neuron − microglia coculture system. Microglial phagocytosis of oAβ was accelerated by MFG-E8 treatment due to increased CD47 expression in the absence of neurotoxic molecule production, such as tumor necrosis factor-α, nitric oxide, and glutamate. MFG-E8 − treated microglia induced nuclear factor E(2 − related factor 2 (Nrf2 − mediated HO-1 production, which also contributed to neuroprotection. Conclusions These results suggest that microglia release MFG-E8 in response to signals from degenerated neurons and that MFG-E8 protects oAβ-induced neuronal cell death

  9. A fluorimetric readout reporting the kinetics of nucleotide-induced human ribonucleotide reductase oligomerization.

    Science.gov (United States)

    Fu, Yuan; Lin, Hongyu; Wisitpitthaya, Somsinee; Blessing, William A; Aye, Yimon

    2014-11-24

    Human ribonucleotide reductase (hRNR) is a target of nucleotide chemotherapeutics in clinical use. The nucleotide-induced oligomeric regulation of hRNR subunit α is increasingly being recognized as an innate and drug-relevant mechanism for enzyme activity modulation. In the presence of negative feedback inhibitor dATP and leukemia drug clofarabine nucleotides, hRNR-α assembles into catalytically inert hexameric complexes, whereas nucleotide effectors that govern substrate specificity typically trigger α-dimerization. Currently, both knowledge of and tools to interrogate the oligomeric assembly pathway of RNR in any species in real time are lacking. We therefore developed a fluorimetric assay that reliably reports on oligomeric state changes of α with high sensitivity. The oligomerization-directed fluorescence quenching of hRNR-α, covalently labeled with two fluorophores, allows for direct readout of hRNR dimeric and hexameric states. We applied the newly developed platform to reveal the timescales of α self-assembly, driven by the feedback regulator dATP. This information is currently unavailable, despite the pharmaceutical relevance of hRNR oligomeric regulation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Membrane-mediated oligomerization of G protein coupled receptors and its implications for GPCR function

    Directory of Open Access Journals (Sweden)

    Stefan Gahbauer

    2016-10-01

    Full Text Available The dimerization or even oligomerization of G protein coupled receptors (GPCRs causes ongoing, controversial debates about its functional role and the coupled biophysical, biochemical or biomedical implications. A continously growing number of studies hints to a relation between oligomerization and function of GPCRs and strengthens the assumption that receptor assembly plays a key role in the regulation of protein function. Additionally, progress in the structural analysis of GPCR-G protein and GPCR-ligand interactions allows to distinguish between actively functional and non-signalling complexes. Recent findings further suggest that the surrounding membrane, i.e. its lipid composition may modulate the preferred dimerization interface and as a result the abundance of distinct dimeric conformations. In this review, the association of GPCRs and the role of the membrane in oligomerization will be discussed. An overview of the different reported oligomeric interfaces is provided and their capability for signaling discussed. The currently available data is summarized with regard to the formation of GPCR oligomers, their structures and dependency on the membrane microenvironment as well as the coupling of oligomerization to receptor function.

  11. Biocatalytically Oligomerized Epicatechin with Potent and Specific Anti-proliferative Activity for Human Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Ramaswamy Nagarajan

    2008-11-01

    Full Text Available Catechins, naturally occurring flavonoids derived from wine and green tea, are known to exhibit multiple health benefits. Epigallocatechin gallate (EGCG is one of the most widely investigated catechins, but its efficacy in cancer therapy is still inconsistent and limited. The poor stability of EGCG has contributed to the disparity in the reported anti-cancer activity and other beneficial properties. Here we report an innovative enzymatic strategy for the oligomerization of catechins (specifically epicatechin that yields stable, water-soluble oligomerized epicatechins with enhanced and highly specific anti-proliferative activity for human breast cancer cells. This one-pot oxidative oligomerization is carried out in ambient conditions using Horseradish Peroxidase (HRP as a catalyst yielding water-soluble oligo(epicatechins. The oligomerized epicatechins obtained exhibit excellent growth inhibitory effects against human breast cancer cells with greater specificity towards growth-inhibiting cancer cells as opposed to normal cells, achieving a high therapeutic differential. Our studies indicate that water-soluble oligomeric epicatechins surpass EGCG in stability, selectivity and efficacy at lower doses.

  12. Interplay of histidine residues of the Alzheimer’s disease Aβ peptide governs its Zn-induced oligomerization

    Science.gov (United States)

    Istrate, Andrey N.; Kozin, Sergey A.; Zhokhov, Sergey S.; Mantsyzov, Alexey B.; Kechko, Olga I.; Pastore, Annalisa; Makarov, Alexander A.; Polshakov, Vladimir I.

    2016-02-01

    Conformational changes of Aβ peptide result in its transformation from native monomeric state to the toxic soluble dimers, oligomers and insoluble aggregates that are hallmarks of Alzheimer’s disease (AD). Interactions of zinc ions with Aβ are mediated by the N-terminal Aβ1-16 domain and appear to play a key role in AD progression. There is a range of results indicating that these interactions trigger the Aβ plaque formation. We have determined structure and functional characteristics of the metal binding domains derived from several Aβ variants and found that their zinc-induced oligomerization is governed by conformational changes in the minimal zinc binding site 6HDSGYEVHH14. The residue H6 and segment 11EVHH14, which are part of this site are crucial for formation of the two zinc-mediated interaction interfaces in Aβ. These structural determinants can be considered as promising targets for rational design of the AD-modifying drugs aimed at blocking pathological Aβ aggregation.

  13. Deaths: leading causes for 2010.

    Science.gov (United States)

    Heron, Melonie

    2013-12-20

    This report presents final 2010 data on the 10 leading causes of death in the United States by age, sex, race, and Hispanic origin. Leading causes of infant, neonatal, and postneonatal death are also presented. This report supplements the Division of Vital Statistics' annual report of final mortality statistics. Data in this report are based on information from all death certificates filed in the 50 states and the District of Columbia in 2010. Causes of death classified by the International Classification of Diseases, Tenth Revision (ICD-10) are ranked according to the number of deaths assigned to rankable causes. Cause-of-death statistics are based on the underlying cause of death. In 2010, the 10 leading causes of death were, in rank order: Diseases of heart; Malignant neoplasms; Chronic lower respiratory diseases; Cerebrovascular diseases; Accidents (unintentional injuries); Alzheimer's disease; Diabetes mellitus; Nephritis, nephrotic syndrome and nephrosis; Influenza and pneumonia; and Intentional self-harm (suicide). These 10 causes accounted for 75% of all deaths occurring in the United States. Differences in the rankings are evident by age, sex, race, and Hispanic origin. Leading causes of infant death for 2010 were, in rank order: Congenital malformations, deformations and chromosomal abnormalities; Disorders related to short gestation and low birth weight, not elsewhere classified; Sudden infant death syndrome; Newborn affected by maternal complications of pregnancy; Accidents (unintentional injuries); Newborn affected by complications of placenta, cord and membranes; Bacterial sepsis of newborn; Respiratory distress of newborn; Diseases of the circulatory system; and Necrotizing enterocolitis of newborn. Important variations in the leading causes of infant death are noted for the neonatal and post-neonatal periods. All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source

  14. Reactive bay functionalized perylene monoimide-polyhedral oligomeric silsesquioxane organic electronic dye

    Directory of Open Access Journals (Sweden)

    Wangatia Lodrick Makokha

    2015-03-01

    Full Text Available Aggregation-induced quenching is particularly detrimental in perylene diimides, which are characterized by a near-unity fluorescence quantum yield in solution but are far less emissive in the solid state. Previously, perylene diimide has been improved by linking it to the inorganic cage of polyhedral oligomeric silsesquioxanes. As a further study on perylene diimidepolyhedral oligomeric silsesquioxanes, we report on a double functionalized molecular structure, which can be used for substitution at the bay area and as a side group in other materials. Typical solution absorption and emission features of the perylene diimide fragment have been observed in this new reactive perylene diimide-polyhedral oligomeric silsesquioxane. Moreover, reduced stacking during aggregation and spherical particles exhibiting solid fluorescence have been obtained. Organic semiconducting material with enhanced solid state photophysical properties, like solid fluorescence is a subject of great interest owing to its possible high-tech applications in optoelectronic devices.

  15. Transient structural distortion of metal-free Cu/Zn superoxide dismutase triggers aberrant oligomerization

    DEFF Research Database (Denmark)

    Teilum, Kaare; Smith, Melanie H; Schulz, Eike

    2009-01-01

    remained enigmatic, however, as is the case in other protein-misfolding diseases. Here, we target the critical conformational change that defines the earliest step toward aggregation. Using nuclear spin relaxation dispersion experiments, we identified a short-lived (0.4 ms) and weakly populated (0.......7%) conformation of metal-depleted SOD1 that triggers aberrant oligomerization. This excited state emanates from the folded ground state and is suppressed by metal binding, but is present in both the disulfide-oxidized and disulfide-reduced forms of the protein. Our results pinpoint a perturbed region......Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease linked to the misfolding of Cu/Zn superoxide dismutase (SOD1). ALS-related defects in SOD1 result in a gain of toxic function that coincides with aberrant oligomerization. The structural events triggering oligomerization have...

  16. Controlling amyloid-beta peptide(1-42) oligomerization and toxicity by fluorinated nanoparticles.

    Science.gov (United States)

    Saraiva, Ana M; Cardoso, Isabel; Pereira, M Carmo; Coelho, Manuel A N; Saraiva, Maria João; Möhwald, Helmuth; Brezesinski, Gerald

    2010-09-03

    The amyloid-beta peptide (Abeta) is a major fibrillar component of neuritic plaques in Alzheimer's disease brains and is related to the pathogenesis of the disease. Soluble oligomers that precede fibril formation have been proposed as the main neurotoxic species that contributes to neurodegeneration and dementia. We hypothesize that oligomerization and cytotoxicity can be repressed by nanoparticles (NPs) that induce conformational changes in Abeta42. We show here that fluorinated and hydrogenated NPs with different abilities to change Abeta42 conformation influence oligomerization as assessed by atomic force microscopy, immunoblot and SDS-PAGE. Fluorinated NPs, which promote an increase in alpha-helical content, exert an antioligomeric effect, whereas hydrogenated analogues do not and lead to aggregation. Cytotoxicity assays confirmed our hypothesis by indicating that the conformational conversion of Abeta42 into an alpha-helical-enriched secondary structure also has antiapoptotic activity, thereby increasing the viability of cells treated with oligomeric species.

  17. Catalyst-controlled oligomerization for the collective synthesis of polypyrroloindoline natural products.

    Science.gov (United States)

    Jamison, Christopher R; Badillo, Joseph J; Lipshultz, Jeffrey M; Comito, Robert J; MacMillan, David W C

    2017-12-01

    In nature, many organisms generate large families of natural product metabolites that have related molecular structures as a means to increase functional diversity and gain an evolutionary advantage against competing systems within the same environment. One pathway commonly employed by living systems to generate these large classes of structurally related families is oligomerization, wherein a series of enzymatically catalysed reactions is employed to generate secondary metabolites by iteratively appending monomers to a growing serial oligomer chain. The polypyrroloindolines are an interesting class of oligomeric natural products that consist of multiple cyclotryptamine subunits. Herein we describe an iterative application of asymmetric copper catalysis towards the synthesis of six distinct oligomeric polypyrroloindoline natural products: hodgkinsine, hodgkinsine B, idiospermuline, quadrigemine H and isopsychotridine B and C. Given the customizable nature of the small-molecule catalysts employed, we demonstrate that this strategy is further amenable to the construction of quadrigemine H-type alkaloids not isolated previously from natural sources.

  18. N-(1-Pyrenyl Maleimide Induces Bak Oligomerization and Mitochondrial Dysfunction in Jurkat Cells

    Directory of Open Access Journals (Sweden)

    Pei-Rong Huang

    2015-01-01

    Full Text Available N-(1-pyrenyl maleimide (NPM is a fluorescent reagent that is frequently used as a derivatization agent for the detection of thio-containing compounds. NPM has been shown to display a great differential cytotoxicity against hematopoietic cancer cells. In this study, the molecular mechanism by which NPM induces apoptosis was examined. Here, we show that treatment of Jurkat cells with NPM leads to Bak oligomerization, loss of mitochondrial membrane potential (Δψm, and release of cytochrome C from mitochondria to cytosol. Induction of Bak oligomerization appears to play a critical role in NPM-induced apoptosis, as downregulation of Bak by shRNA significantly prevented NPM-induced apoptosis. Inhibition of caspase 8 by Z-IETD-FMK and/or depletion of Bid did not affect NPM-induced oligomerization of Bak. Taken together, these results suggest that NPM-induced apoptosis is mediated through a pathway that is independent of caspase-8 activation.

  19. Zn(2+) site engineering at the oligomeric interface of the dopamine transporter.

    Science.gov (United States)

    Norgaard-Nielsen, Kristine; Norregaard, Lene; Hastrup, Hanne; Javitch, Jonathan A; Gether, Ulrik

    2002-07-31

    Increasing evidence suggests that Na(+)/Cl(-)-dependent neurotransmitter transporters exist as homo-oligomeric proteins. However, the functional implication of this oligomerization remains unclear. Here we demonstrate the engineering of a Zn(2+) binding site at the predicted dimeric interface of the dopamine transporter (DAT) corresponding to the external end of transmembrane segment 6. Upon binding to this site, which involves a histidine inserted in position 310 (V310H) and the endogenous Cys306 within the same DAT molecule, Zn(2+) potently inhibits [(3)H]dopamine uptake. These data provide indirect evidence that conformational changes critical for the translocation process may occur at the interface between two transporter molecules in the oligomeric structure.

  20. Structure of the first PDZ domain of human PSD-93

    DEFF Research Database (Denmark)

    Fiorentini, Monica; Nielsen, Ann Kallehauge; Kristensen, Ole

    2009-01-01

    The crystal structure of the PDZ1 domain of human PSD-93 has been determined to 2.0 A resolution. The PDZ1 domain forms a crystallographic trimer that is also predicted to be stable in solution. The main contributions to the stabilization of the trimer seem to arise from interactions involving...... the PDZ1-PDZ2 linker region at the extreme C-terminus of PDZ1, implying that the oligomerization that is observed is not of biological significance in full-length PSD-93. Comparison of the structures of the binding cleft of PSD-93 PDZ1 with the previously reported structures of PSD-93 PDZ2 and PDZ3...

  1. osFP: a web server for predicting the oligomeric states of fluorescent proteins.

    Science.gov (United States)

    Simeon, Saw; Shoombuatong, Watshara; Anuwongcharoen, Nuttapat; Preeyanon, Likit; Prachayasittikul, Virapong; Wikberg, Jarl E S; Nantasenamat, Chanin

    2016-01-01

    Currently, monomeric fluorescent proteins (FP) are ideal markers for protein tagging. The prediction of oligomeric states is helpful for enhancing live biomedical imaging. Computational prediction of FP oligomeric states can accelerate the effort of protein engineering efforts of creating monomeric FPs. To the best of our knowledge, this study represents the first computational model for predicting and analyzing FP oligomerization directly from the amino acid sequence. After data curation, an exhaustive data set consisting of 397 non-redundant FP oligomeric states was compiled from the literature. Results from benchmarking of the protein descriptors revealed that the model built with amino acid composition descriptors was the top performing model with accuracy, sensitivity and specificity in excess of 80% and MCC greater than 0.6 for all three data subsets (e.g. training, tenfold cross-validation and external sets). The model provided insights on the important residues governing the oligomerization of FP. To maximize the benefit of the generated predictive model, it was implemented as a web server under the R programming environment. osFP affords a user-friendly interface that can be used to predict the oligomeric state of FP using the protein sequence. The advantage of osFP is that it is platform-independent meaning that it can be accessed via a web browser on any operating system and device. osFP is freely accessible at http://codes.bio/osfp/ while the source code and data set is provided on GitHub at https://github.com/chaninn/osFP/.Graphical Abstract.

  2. Methyl methacrylate oligomerically-modified clay and its poly(methyl methacrylate) nanocomposites

    International Nuclear Information System (INIS)

    Zheng Xiaoxia; Jiang, David D.; Wilkie, Charles A.

    2005-01-01

    A methyl methacrylate oligomerically-modified clay was used to prepare poly(methyl methacrylate) clay nanocomposites by melt blending and the effect of the clay loading level on the modified clay and corresponding nanocomposite was studied. These nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and cone calorimetry. The results show a mixed intercalated/delaminated morphology with good nanodispersion. The compatibility between the methylacrylate-subsituted clay and poly(methyl methacrylate) (PMMA) are greatly improved compared to other oligomerically-modified clays

  3. Conformational detection of p53's oligomeric state by FlAsH Fluorescence

    OpenAIRE

    Webber, Tawnya M.; Allen, Andrew C.; Ma, Wai Kit; Molloy, Rhett G.; Kettelkamp, Charisse N.; Dow, Caitlin A.; Gage, Matthew J.

    2009-01-01

    The p53 tumor suppressor protein is a critical checkpoint in prevention of tumor formation, and the function of p53 is dependent on proper formation of the active tetramer. In vitro studies have shown that p53 binds DNA most efficiently as a tetramer, though inactive p53 is predicted to be monomeric in vivo. We demonstrate that FlAsH binding can be used to distinguish between oligomeric states of p53, providing a potential tool to explore p53 oligomerization in vivo. The FlAsH tetra-cysteine ...

  4. 40 CFR 721.3100 - Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine. 721.3100 Section 721.3100 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.3100 Oligomeric silicic acid ester compound with a...

  5. Births and deaths including fetal deaths

    Data.gov (United States)

    U.S. Department of Health & Human Services — Access to a variety of United States birth and death files including fetal deaths: Birth Files, 1968-2009; 1995-2005; Fetal death file, 1982-2005; Mortality files,...

  6. Death and digital photography

    Directory of Open Access Journals (Sweden)

    Ennis, Helen

    2011-01-01

    Full Text Available This essay considers new possibilities for photographing the dying and dead in Australia that have been enabled by digital technologies. It argues that vernacular digital photographs demonstrate unprecedented degrees of control and privacy and further that they are purposefully withheld from public view, thus raising issues about visibility and secrecy.Some historical context is provided. Post mortem photographs were not uncommon in the nineteenth century but were in the domain of professional studio photographers. Commissioning post mortem portraits was rare for most of the twentieth century, due to changing attitudes to death and the transformation of the photographic industry. Photographing the deceased re-emerged in the 1980s, notably in the area of neonatal death.In the last five years death-related vernacular photographs have begun to proliferate. Unlike analogue processes, digital photography bypasses the involvement of others in processing and printing private images. Distribution to intimates can be achieved instantaneously via the internet, reinforcing social and familial connections.Vernacular digital photographs of the deceased do not address historical tradition but share their domestic and intimate contexts. Nor do they belong to a unified group, yet they have a common vocabulary which emphasises specificity and detail.

  7. Death and Digital Photography

    Directory of Open Access Journals (Sweden)

    Helen Ennis

    2011-03-01

    Full Text Available This essay considers new possibilities for photographing the dying and dead in Australia that have been enabled by digital technologies. It argues that vernacular digital photographs demonstrate unprecedented degrees of control and privacy and further that they are purposefully withheld from public view, thus raising issues about visibility and secrecy. Some historical context is provided. Post mortem photographs were not uncommon in the nineteenth century but were in the domain of professional studio photographers. Commissioning post mortem portraits was rare for most of the twentieth century, due to changing attitudes to death and the transformation of the photographic industry. Photographing the deceased re-emerged in the 1980s, notably in the area of neonatal death. In the last five years death-related vernacular photographs have begun to proliferate. Unlike analogue processes, digital photography bypasses the involvement of others in processing and printing private images. Distribution to intimates can be achieved instantaneously via the internet, reinforcing social and familial connections. Vernacular digital photographs of the deceased do not address historical tradition but share their domestic and intimate contexts. Nor do they belong to a unified group, yet they have a common vocabulary which emphasises specificity and detail.

  8. Influence of oligomeric resins on traction and rolling resistance of silica tire treads

    NARCIS (Netherlands)

    Vleugels, N.; Pille-Wolf, W.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2016-01-01

    This study concerns the silica-reinforcement of synthetic rubber compounds for passenger tire treads with the objective to gain insight into the beneficial effects of oligomeric resins, derived from natural and synthetic monomers, on the major tire performance factors: rolling resistance and (wet)

  9. Understanding the Influence of oligomeric resins on traction and rolling resistance of silica tire treads

    NARCIS (Netherlands)

    Vleugels, N.; Pille-Wolf, W.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2015-01-01

    This study concerns the silica reinforcement of styrene–butadiene rubber compounds for passenger car tire treads, with the objective of gaining greater insight into the beneficial effects of oligomeric resins. The major tire performance factors predicted are rolling resistance and (wet) skid

  10. Influence of oligomeric resins on traction and rolling resistance of silica tire treads

    NARCIS (Netherlands)

    Vleugels, N.; Pille-Wolf, W.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2013-01-01

    This study concerns the silica-reinforcement of synthetic rubber compounds for passenger tire treads with the objective to gain insight into the beneficial effects of oligomeric resins, derived from natural and synthetic monomers, on the major tire performance factors: Rolling Resistance and (Wet)

  11. Oligomerization of a Glucagon-like Peptide 1 Analog: Bridging Experiment and Simulations

    DEFF Research Database (Denmark)

    Frederiksen, Tine Maja; Sønderby, Pernille; Ryberg, Line A.

    2015-01-01

    The glucagon-like peptide 1 (GLP-1) analog, liraglutide, is a GLP-1 agonist and is used in the treatment of type-2 diabetes mellitus and obesity. From a pharmaceutical perspective, it is important to know the oligomerization state of liraglutide with respect to stability. Compared to GLP-1...

  12. Cobalt Oxide on N-Doped Carbon for 1-Butene Oligomerization to Produce Linear Octenes

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dongting [Department; Xu, Zhuoran [Department; Chada, Joseph P. [Department; Carrero, Carlos A. [Department; Rosenfeld, Devon C. [The Dow Chemical Company, 2301 N. Brazosport Boulevard, Freeport, Texas 77541-3257, United States; Rogers, Jessica L. [The Dow Chemical Company, 2301 N. Brazosport Boulevard, Freeport, Texas 77541-3257, United States; Hermans, Ive [Department; Huber, George W. [Department

    2017-10-02

    Cobalt oxide supported on N-doped carbon catalysts were investigated for 1-butene oligomerization. The materials were synthesized by treating activated carbon with nitric acid and subsequently with NH3 at 200, 400, 600, and 800 °C, followed by impregnation with cobalt. The 1-butene oligomerization selectivity increased with ammonia treatment temperature of the carbon support. The oligomerization selectivity of cobalt oxide on N-doped carbon synthesized at 800 °C (800A-CoOx/N-C) is 2.6 times higher than previously reported cobalt oxide on N-doped carbon synthesized with NH4OH (2A-CoOx/N-C). Over 70% of the butene dimers were linear C8 olefins for all catalysts. The oligomerization selectivity increased with 1-butene conversion. The catalysts were characterized by elemental analysis, N2 adsorption, X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and X-ray photoelectron spectroscopy (XPS). The nitrogen content of the catalysts increases with ammonia treatment temperature as confirmed by elemental analysis. The surface content of pyridinic nitrogen with a binding energy of 398.4 ± 0.1 eV increased with ammonia treatment temperature as evidenced by deconvolution of N 1s XPS spectra.

  13. Pro-inflammatory delipidizing cytokines reduce adiponectin secretion from human adipocytes without affecting adiponectin oligomerization

    NARCIS (Netherlands)

    Simons, Peter J.; van den Pangaart, Petra S.; Aerts, Johannes M. F. G.; Boon, Louis

    2007-01-01

    Adiponectin and, especially, its oligomeric complex composition have been suggested to be critical in determining insulin sensitivity. Pro-inflammatory cytokines play an important role in the development of insulin resistance in obesity and associated diseases. Therefore, we investigated the effect

  14. Mechanics of the mannitol transporter from Escherichia coli : substrate-probing and oligomeric structure

    NARCIS (Netherlands)

    Veldhuis, Gertjan

    2006-01-01

    Gertjan Veldhuis bestudeerde de mannitoltransporter van Escherichia coli, EnzymeIImtl (EIImtl), om meer inzicht te krijgen in het bindingsmechanisme en de oligomere toestand van dit membraaneiwit. Hij concludeerde onder andere dat dimeer EIImtl één mannitol bindt, de dimeer zeer stabiel is en dat

  15. RIG-I self-oligomerization is either dispensable or very transient for signal transduction.

    Directory of Open Access Journals (Sweden)

    Jade Louber

    Full Text Available Effective host defence against viruses depends on the rapid triggering of innate immunity through the induction of a type I interferon (IFN response. To this end, microbe-associated molecular patterns are detected by dedicated receptors. Among them, the RIG-I-like receptors RIG-I and MDA5 activate IFN gene expression upon sensing viral RNA in the cytoplasm. While MDA5 forms long filaments in vitro upon activation, RIG-I is believed to oligomerize after RNA binding in order to transduce a signal. Here, we show that in vitro binding of synthetic RNA mimicking that of Mononegavirales (Ebola, rabies and measles viruses leader sequences to purified RIG-I does not induce RIG-I oligomerization. Furthermore, in cells devoid of endogenous functional RIG-I-like receptors, after activation of exogenous Flag-RIG-I by a 62-mer-5'ppp-dsRNA or by polyinosinic:polycytidylic acid, a dsRNA analogue, or by measles virus infection, anti-Flag immunoprecipitation and specific elution with Flag peptide indicated a monomeric form of RIG-I. Accordingly, when using the Gaussia Luciferase-Based Protein Complementation Assay (PCA, a more sensitive in cellula assay, no RIG-I oligomerization could be detected upon RNA stimulation. Altogether our data indicate that the need for self-oligomerization of RIG-I for signal transduction is either dispensable or very transient.

  16. Collagen XII and XIV, New Partners of Cartilage Oligomeric Matrix Protein in the Skin Extracellular Matrix Suprastructure*

    Science.gov (United States)

    Agarwal, Pallavi; Zwolanek, Daniela; Keene, Douglas R.; Schulz, Jan-Niklas; Blumbach, Katrin; Heinegård, Dick; Zaucke, Frank; Paulsson, Mats; Krieg, Thomas; Koch, Manuel; Eckes, Beate

    2012-01-01

    The tensile and scaffolding properties of skin rely on the complex extracellular matrix (ECM) that surrounds cells, vasculature, nerves, and adnexus structures and supports the epidermis. In the skin, collagen I fibrils are the major structural component of the dermal ECM, decorated by proteoglycans and by fibril-associated collagens with interrupted triple helices such as collagens XII and XIV. Here we show that the cartilage oligomeric matrix protein (COMP), an abundant component of cartilage ECM, is expressed in healthy human skin. COMP expression is detected in the dermal compartment of skin and in cultured fibroblasts, whereas epidermis and HaCaT cells are negative. In addition to binding collagen I, COMP binds to collagens XII and XIV via their C-terminal collagenous domains. All three proteins codistribute in a characteristic narrow zone in the superficial papillary dermis of healthy human skin. Ultrastructural analysis by immunogold labeling confirmed colocalization and further revealed the presence of COMP along with collagens XII and XIV in anchoring plaques. On the basis of these observations, we postulate that COMP functions as an adapter protein in human skin, similar to its function in cartilage ECM, by organizing collagen I fibrils into a suprastructure, mainly in the vicinity of anchoring plaques that stabilize the cohesion between the upper dermis and the basement membrane zone. PMID:22573329

  17. Collagen XII and XIV, new partners of cartilage oligomeric matrix protein in the skin extracellular matrix suprastructure.

    Science.gov (United States)

    Agarwal, Pallavi; Zwolanek, Daniela; Keene, Douglas R; Schulz, Jan-Niklas; Blumbach, Katrin; Heinegård, Dick; Zaucke, Frank; Paulsson, Mats; Krieg, Thomas; Koch, Manuel; Eckes, Beate

    2012-06-29

    The tensile and scaffolding properties of skin rely on the complex extracellular matrix (ECM) that surrounds cells, vasculature, nerves, and adnexus structures and supports the epidermis. In the skin, collagen I fibrils are the major structural component of the dermal ECM, decorated by proteoglycans and by fibril-associated collagens with interrupted triple helices such as collagens XII and XIV. Here we show that the cartilage oligomeric matrix protein (COMP), an abundant component of cartilage ECM, is expressed in healthy human skin. COMP expression is detected in the dermal compartment of skin and in cultured fibroblasts, whereas epidermis and HaCaT cells are negative. In addition to binding collagen I, COMP binds to collagens XII and XIV via their C-terminal collagenous domains. All three proteins codistribute in a characteristic narrow zone in the superficial papillary dermis of healthy human skin. Ultrastructural analysis by immunogold labeling confirmed colocalization and further revealed the presence of COMP along with collagens XII and XIV in anchoring plaques. On the basis of these observations, we postulate that COMP functions as an adapter protein in human skin, similar to its function in cartilage ECM, by organizing collagen I fibrils into a suprastructure, mainly in the vicinity of anchoring plaques that stabilize the cohesion between the upper dermis and the basement membrane zone.

  18. Solution structure of the receptor tyrosine kinase EphB2 SAM domain and identification of two distinct homotypic interaction sites.

    OpenAIRE

    Smalla, M.; Schmieder, P.; Kelly, M.; Ter Laak, A.; Krause, G.; Ball, L.; Wahl, M.; Bork, P.; Oschkinat, H.

    1999-01-01

    The sterile alpha motif (SAM) is a protein interaction domain of around 70 amino acids present predominantly in the N- and C-termini of more than 60 diverse proteins that participate in signal transduction and transcriptional repression. SAM domains have been shown to homo- and hetero-oligomerize and to mediate specific protein-protein interactions. A highly conserved subclass of SAM domains is present at the intracellular C-terminus of more than 40 Eph receptor tyrosine kinases that are invo...

  19. Crystal structure studies of NADP{sup +} dependent isocitrate dehydrogenase from Thermus thermophilus exhibiting a novel terminal domain

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S.M. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India); Pampa, K.J. [Department of Studies in Microbiology, University of Mysore, Mysore 570 006 (India); Manjula, M. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India); Abdoh, M.M.M. [Department of Physics, Faculty of Science, An-Najah National University, Nablus, West Bank, Palestine (Country Unknown); Kunishima, Naoki [Advanced Protein Crystallography Research Group, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148 (Japan); Lokanath, N.K., E-mail: lokanath@physics.uni-mysore.ac.in [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India)

    2014-06-20

    Highlights: • We determined the structure of isocitrate dehydrogenase with citrate and cofactor. • The structure reveals a unique novel terminal domain involved in dimerization. • Clasp domain shows significant difference, and catalytic residues are conserved. • Oligomerization of the enzyme is quantized with subunit-subunit interactions. • Novel domain of this enzyme is classified as subfamily of the type IV. - Abstract: NADP{sup +} dependent isocitrate dehydrogenase (IDH) is an enzyme catalyzing oxidative decarboxylation of isocitrate into oxalosuccinate (intermediate) and finally the product α-ketoglutarate. The crystal structure of Thermus thermophilus isocitrate dehydrogenase (TtIDH) ternary complex with citrate and cofactor NADP{sup +} was determined using X-ray diffraction method to a resolution of 1.80 Å. The overall fold of this protein was resolved into large domain, small domain and a clasp domain. The monomeric structure reveals a novel terminal domain involved in dimerization, very unique and novel domain when compared to other IDH’s. And, small domain and clasp domain showing significant differences when compared to other IDH’s of the same sub-family. The structure of TtIDH reveals the absence of helix at the clasp domain, which is mainly involved in oligomerization in other IDH’s. Also, helices/beta sheets are absent in the small domain, when compared to other IDH’s of the same sub family. The overall TtIDH structure exhibits closed conformation with catalytic triad residues, Tyr144-Asp248-Lys191 are conserved. Oligomerization of the protein is quantized using interface area and subunit–subunit interactions between protomers. Overall, the TtIDH structure with novel terminal domain may be categorized as a first structure of subfamily of type IV.

  20. Domain crossing

    DEFF Research Database (Denmark)

    Schraefel, M. C.; Rouncefield, Mark; Kellogg, Wendy

    2012-01-01

    In CSCW, how much do we need to know about another domain/culture before we observe, intersect and intervene with designs. What optimally would that other culture need to know about us? Is this a “how long is a piece of string” question, or an inquiry where we can consider a variety of contexts a...

  1. The C-terminal domain of TRPV4 is essential for plasma membrane localization.

    Science.gov (United States)

    Becker, Daniel; Müller, Margarethe; Leuner, Kristina; Jendrach, Marina

    2008-02-01

    Many members of the TRP superfamily oligomerize in the ER before trafficking to the plasma membrane. For membrane localization of the non-selective cation channel TRPV4 specific domains in the N-terminus are required, but the role of the C-terminus in the oligomerization and trafficking process has been not determined until now. Therefore, the localization of recombinant TRPV4 in two cell models was analyzed: HaCaT keratinocytes that express TRPV4 endogenously were compared to CHO cells that are devoid of endogenous TRPV4. When deletions were introduced in the C-terminal domain three states of TRPV4 localization were defined: a truncated TRPV4 protein of 855 amino acids was exported to the plasma membrane like the full-length channel (871 aa) and was also functional. Mutants with a length of 828 to 844 amino acids remained in the ER of CHO cells, but in HaCaT cells plasma membrane localization was partially rescued by oligomerization with endogenous TRPV4. This was confirmed by coexpression of recombinant full-length TRPV4 together with these deletion mutants, which resulted in an almost complete plasma membrane localization of both proteins and significant FRET in the plasma membrane and the ER. All deletions upstream of amino acid 828 resulted in total ER retention that could not rescued by coexpression with the full-length protein. However, these deletion mutants did not impair export of full-length TRPV4, implying that no oligomerization took place. These data indicate that the C-terminus of TRPV4 is required for oligomerization, which takes place in the ER and precedes plasma membrane trafficking.

  2. Screening of drugs inhibiting in vitro oligomerization of Cu/Zn-superoxide dismutase with a mutation causing amyotrophic lateral sclerosis

    Directory of Open Access Journals (Sweden)

    Itsuki Anzai

    2016-08-01

    Full Text Available Dominant mutations in Cu/Zn-superoxide dismutase (SOD1 gene have been shown to cause a familial form of amyotrophic lateral sclerosis (SOD1-ALS. A major pathological hallmark of this disease is abnormal accumulation of mutant SOD1 oligomers in the affected spinal motor neurons. While no effective therapeutics for SOD1-ALS is currently available, SOD1 oligomerization will be a good target for developing cures of this disease. Recently, we have reproduced the formation of SOD1 oligomers abnormally cross-linked via disulfide bonds in a test tube. Using our in vitro model of SOD1 oligomerization, therefore, we screened 640 FDA-approved drugs for inhibiting the oligomerization of SOD1 proteins, and three effective classes of chemical compounds were identified. Those hit compounds will provide valuable information on the chemical structures for developing a novel drug candidate suppressing the abnormal oligomerization of mutant SOD1 and possibly curing the disease.

  3. Hydration effect on the electronic transport properties of oligomeric phenylene ethynylene molecular junctions

    International Nuclear Information System (INIS)

    Zong-Liang, Li; Huai-Zhi, Li; Yong, Ma; Guang-Ping, Zhang; Chuan-Kui, Wang

    2010-01-01

    A first-principles computational method based on the hybrid density functional theory is developed to simulate the electronic transport properties of oligomeric phenylene ethynylene molecular junctions with H 2 O molecules accumulated in the vicinity as recently reported by Na et al. [Nanotechnology 18 424001 (2007)]. The numerical results show that the hydrogen bonds between the oxygen atoms of the oligomeric phenylene ethynylene molecule and H 2 O molecules result in the localisation of the molecular orbitals and lead to the lower transition peaks. The H 2 O molecular chains accumulated in the vicinity of the molecular junction can not only change the electronic structure of the molecular junctions, but also open additional electronic transport pathways. The obvious influence of H 2 O molecules on the electronic structure of the molecular junction and its electronic transport properties is thus demonstrated. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  4. Receptor oligomerization in family B1 of G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Roed, Sarah Norklit; Ørgaard, Anne; Jørgensen, Rasmus

    2012-01-01

    , the glucagon receptor, and the receptors for parathyroid hormone (PTHR1 and PTHR2). The dysregulation of several family B1 receptors is involved in diseases, such as diabetes, chronic inflammation, and osteoporosis which underlines the pathophysiological importance of this GPCR subfamily. In spite of this......, investigation of family B1 receptor oligomerization and especially its pharmacological importance is still at an early stage. Even though GPCR oligomerization is a well-established phenomenon, there is a need for more investigations providing a direct link between these interactions and receptor functionality......The superfamily of the seven transmembrane G-protein-coupled receptors (7TM/GPCRs) is the largest family of membrane-associated receptors. GPCRs are involved in the pathophysiology of numerous human diseases, and they constitute an estimated 30-40% of all drug targets. During the last two decades...

  5. Anesthetic propofol attenuates the isoflurane-induced caspase-3 activation and Aβ oligomerization.

    Directory of Open Access Journals (Sweden)

    Yiying Zhang

    Full Text Available Accumulation and deposition of β-amyloid protein (Aβ are the hallmark features of Alzheimer's disease. The inhalation anesthetic isoflurane has been shown to induce caspase activation and increase Aβ accumulation. In addition, recent studies suggest that isoflurane may directly promote the formation of cytotoxic soluble Aβ oligomers, which are thought to be the key pathological species in AD. In contrast, propofol, the most commonly used intravenous anesthetic, has been reported to have neuroprotective effects. We therefore set out to compare the effects of isoflurane and propofol alone and in combination on caspase-3 activation and Aβ oligomerization in vitro and in vivo. Naïve and stably-transfected H4 human neuroglioma cells that express human amyloid precursor protein, the precursor for Aβ; neonatal mice; and conditioned cell culture media containing secreted human Aβ40 or Aβ42 were treated with isoflurane and/or propofol. Here we show for the first time that propofol can attenuate isoflurane-induced caspase-3 activation in cultured cells and in the brain tissues of neonatal mice. Furthermore, propofol-mediated caspase inhibition occurred when there were elevated levels of Aβ. Finally, isoflurane alone induces Aβ42, but not Aβ40, oligomerization, and propofol can inhibit the isoflurane-mediated oligomerization of Aβ42. These data suggest that propofol may mitigate the caspase-3 activation by attenuating the isoflurane-induced Aβ42 oligomerization. Our findings provide novel insights into the possible mechanisms of isoflurane-induced neurotoxicity that may aid in the development of strategies to minimize potential adverse effects associated with the administration of anesthetics to patients.

  6. Characterization and ageing study of poly(lactic acid) films plasticized with oligomeric lactic acid

    OpenAIRE

    Burgos, Nuria; Martino, Verónica P.; Jiménez, Alfonso

    2013-01-01

    Poly(lactic acid) (PLA) was melt-blended with a bio-based oligomeric lactic acid (OLA) plasticizer at different concentrations between 15 wt% and 25 wt% in order to enhance PLA ductility and to get a fully biodegradable material with potential application in films manufacturing. OLA was an efficient plasticizer for PLA, as it caused a significant decrease on glass transition temperature (Tg) while improving considerably ductile properties. Only one Tg value was observed in all cases and no ap...

  7. Construction of porous cationic frameworks by crosslinking polyhedral oligomeric silsesquioxane units with N-heterocyclic linkers

    OpenAIRE

    Chen, Guojian; Zhou, Yu; Wang, Xiaochen; Li, Jing; Xue, Shuang; Liu, Yangqing; Wang, Qian; Wang, Jun

    2015-01-01

    In fields of materials science and chemistry, ionic-type porous materials attract increasing attention due to significant ion-exchanging capacity for accessing diversified applications. Facing the fact that porous cationic materials with robust and stable frameworks are very rare, novel tactics that can create new type members are highly desired. Here we report the first family of polyhedral oligomeric silsesquioxane (POSS) based porous cationic frameworks (PCIF-n) with enriched poly(ionic li...

  8. An Investigation of Chemical Landscapes in Aqueous Electrosprays by Tracking Oligomerization of Isoprene

    KAUST Repository

    Junior, Adair Gallo

    2017-12-01

    Electrospray ionization mass spectrometry (ESIMS) is widely used to characterize neutral and ionic species in solvents. Typically, electrical, thermal, and pneumatic potentials are applied to create electrosprays from which charged ionic species are ejected for downstream analysis by mass spectrometry. Most recently, ESIMS has been exploited to investigate ambient proton transfer reactions at air-water interfaces in real time. We assessed the validity of these experiments via complementary laboratory experiments. Specifically, we characterized the products of two reaction scenarios via ESIMS and proton nuclear magnetic resonance (1H-NMR): (i) emulsions of pH-adjusted water and isoprene (C5H8) that were mechanically agitated, and (ii) electrosprays of pH-adjusted water that were collided with gas-phase isoprene. Our experiments unambiguously demonstrate that, while isoprene does not oligomerize in emulsions, it does undergo protonation and oligomerization in electrosprays, both with and without pH-adjusted water, confirming that C-C bonds form along myriad high-energy pathways during electrospray ionization. We also compared our experimental results with some quantum mechanics simulations of isoprene molecules interacting with hydronium at different hydration levels (gas versus liquid phase). In agreement with our experiments, the kinetic barriers to protonation and oligomerization of isoprene were inaccessible under ambient conditions. Rather, the gas-phase chemistries during electrospray ionization drove the oligomerization of isoprene. Therefore, we consider that ESIMS could induce artifacts in interfacial reactions. These findings warrant a reassessment of previous reports on tracking chemistries under ambient conditions at liquid-vapor interfaces via ESIMS. Further, we took some high-speed images of electrosprays where it was possible to observe the main characteristics of the phenomena, i.e. Taylor cone, charge separation, and Coulomb fission. Finally, we took

  9. Stability of human interferon-beta 1: oligomeric human interferon-beta 1 is inactive but is reactivated by monomerization.

    Science.gov (United States)

    Utsumi, J; Yamazaki, S; Kawaguchi, K; Kimura, S; Shimizu, H

    1989-10-05

    Human interferon-beta 1 is extremely stable is a low ionic strength solution of pH 2 such as 10 mM HCl at 37 degrees C. However, the presence of 0.15 M NaCl led to a remarkable loss of antiviral activity. The molecular-sieve high-performance liquid chromatography revealed that, whereas completely active human interferon-beta 1 eluted as a 25 kDa species (monomeric form), the inactivated preparation eluted primarily as a 90 kDa species (oligomeric form). The specific activity (units per mg protein) of the oligomeric form was approx. 10% of that of the monomeric form. This observation shows that oligomeric human interferon-beta 1 is apparently in an inactive form. When the oligomeric eluate was resolved by polyacrylamide gel containing sodium dodecyl sulphate (SDS), it appeared to be monomeric under non-reducing conditions. Monomerization of the oligomeric human interferon-beta 1 by treatment with 1% SDS, fully regenerated its antiviral activity. These results suggest that the inactivation of the human interferon-beta 1 preparation was caused by its oligomerization via hydrophobic interactions without the formation of intermolecular disulphide bonds. These oligomers can be dissociated by SDS to restore biological activity.

  10. Effect Of Oligomeric Enteral Nutrition On Symptoms Of Acute Radiation Enteritis

    International Nuclear Information System (INIS)

    Dubinsky, P.

    2008-01-01

    Radiotherapy of abdominal and pelvic tumours is frequently associated with acute radiation enteritis. Predominant symptoms include diarrhea, watery stools, abdominal pain, nausea and vomiting. There are very few effective interventions available for this condition. Enteral oligomeric nutrition has been used in bowel diseases with functional failure similar to radiation enteritis. The aim of presented work was to observe occurrence of symptoms of radiation enteritis in patients undergoing abdominal or pelvic radiotherapy. Apart from diet and pharmacological therapy, oral oligomeric enteral nutrition (Peptisorb Powder Nutricia) at the dose of 1000 - 2000 ml per day was administered for minimum of 4 days. Planned period of administration was 14 days and longer. Symptoms of radiation enteritis were evaluated at the beginning and in the end of administration. Prevalence of all evaluated symptoms of radiation enteritis was decreased and difference was statistically significant for diarrhea, watery stools, abdominal pain, nausea and vomiting. The use of evaluated oligomeric nutritional support might, in conjunction with pharmacotherapy and diet, alleviate symptoms of acute radiation enteritis and maintain nutritional status of patients. (author)

  11. Chemical activation of bituminous coal for hampering oligomerization of organic contaminants.

    Science.gov (United States)

    Yan, Liang; Sorial, George A

    2011-12-15

    Activated carbons prepared by KOH activation of bituminous coal were studied for hampering oligomerization of phenolic compounds on its surface. A total of 24 activated carbons with different microporosity and BET surface area were created. The effect of the different variables of the activation process (KOH/bituminous coal ratio, heating temperature, activation time, and flow rate of nitrogen gas) on critical carbon parameters was analyzed. The impact of activated carbon on oligomerization was examined by conducting isotherm experiments at a neutral pH on Carbon(exp) produced with optimal characteristics and granular activated carbon (GAC) F400 for phenol, 2-methylphenol and 2-ethylphenol. These isotherms were collected under anoxic (absence of molecular oxygen) and oxic (presence of molecular oxygen) conditions. The single solute adsorption of phenol, 2-methylphenol and 2-ethylphenol on Carbon(exp) showed no obvious differences between oxic and anoxic environment, which indicated that the Carbon(exp) sample is very effective in hampering the oligomerization of phenolic compounds under oxic conditions. On the other hand, F400, which have lower micropore percentage and BET surface area, significant increases in the adsorptive capacity had been observed when molecular oxygen was present. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Homologous ELISA for detection of oligomeric human TNF: properties of the assay.

    Science.gov (United States)

    Petyovka, N; Lyach, L; Voitenok, N N

    1995-10-26

    In order to quantify oligomeric human tumor necrosis factor-alpha (TNF), we have developed a sensitive homologous enzyme-linked immunosorbent assay (Hm-ELISA) using the same monoclonal antibody (MoAb) for both solid and liquid phase. Different anti-TNF MoAb have been compared in terms of their efficacy in the Hm-ELISA, affinity, neutralization capacity and epitope specificity. The data suggest, that effectiveness in the Hm-ELISA may represent a novel characteristic of MoAb. Of the MoAbs tested, 5 N was capable of recognizing oligomeric TNF in the Hm-ELISA with a detection limit of 15 pg/ml. Furthermore, using Hm-ELISA against human TNF, interleukin-8 (IL-8) and lymphotoxin, we have demonstrated that these cytokines are oligomeric in physiological solutions, but are converted into monomeric forms in the presence of the non-ionic detergent Tween 20. High salt buffer was employed to abrogate a nonspecific false positive reaction in the Hm-ELISA found in nearly half of the plasma samples obtained from healthy subjects. Finally, a good correlation between the Hm-ELISA and the L929 bioassay was observed for natural and recombinant TNF measured in human plasma.

  13. Catalytic oligomerization of terminal alkynes promoted by organo-f-complexes

    International Nuclear Information System (INIS)

    Straub, T.; Haskel, A.; Eisen, M.S.

    1995-01-01

    Organoactinides of the type Cp* 2 AcMe 2 (Cp*=C 5 Me 5 ; Ac=Th, U) are active catalyst precursors for the oligomerization of terminal alkynes HC triple-bond CR (R=alkyl, aryl, SiMe 3 ). The regioselectivity and the extent of oligomerization strongly depend on the alkyne substituent R, whereas the catalytic reactivity is similar for 1 and 2. In the presence of one of these organoactinides, for example, HCCSiMe 3 regioselectively oligomerizes to the head-to-tail dimer 3 (5%) and the trimer 4 (95%). 1 and 2 react with the terminal alkynes, releasing methane, to the corresponding bisacetylide complexes which are active species and in the catalytic reactions. The bisacetylide complex (η 5 -C 5 Me 5 ) 2 U(CCPh) 2 was identified by proton NMR spectroscopy. Subsequent insertion of alkyne molecules in the actinide-carbon σ-bonds leads to the formation of actinide-alkenyl complexes. The turnover limiting step is the release of the organic oligomer from the actinide-organyl complex. A species of the latter has been spectroscopically characterized in the trimerization reaction of HCCSiMe 3 . In this poster, the catalytic reactivity of the actinide alkyls 1 and 2 with various mono-substituted alkynes as well as the spectroscopic characterization of the key organometallic intermediate complexes in the catalytic cycle and a detailed mechanistic discussion are given

  14. Crystal Structure of the Oligomeric Form of Lassa Virus Matrix Protein Z.

    Science.gov (United States)

    Hastie, Kathryn M; Zandonatti, Michelle; Liu, Tong; Li, Sheng; Woods, Virgil L; Saphire, Erica Ollmann

    2016-05-01

    The arenavirus matrix protein Z is highly multifunctional and occurs in both monomeric and oligomeric forms. The crystal structure of a dodecamer of Z from Lassa virus, presented here, illustrates a ring-like structure with a highly basic center. Mutagenesis demonstrates that the dimeric interface within the dodecamer and a Lys-Trp-Lys triad at the center of the ring are important for oligomerization. This structure provides an additional template to explore the many functions of Z. The arenavirus Lassa virus causes hundreds of thousands of infections each year, many of which develop into fatal hemorrhagic fever. The arenavirus matrix protein Z is multifunctional, with at least four distinct roles. Z exists in both monomeric and oligomeric forms, each of which likely serves a specific function in the viral life cycle. Here we present the dodecameric form of Lassa virus Z and demonstrate that Z forms a "wreath" with a highly basic center. This structure and that of monomeric Z now provide a pair of critical templates by which the multiple roles of Z in the viral life cycle may be interpreted. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  15. The role of oligomerization and cooperative regulation in protein function: the case of tryptophan synthase.

    Directory of Open Access Journals (Sweden)

    M Qaiser Fatmi

    Full Text Available The oligomerization/co-localization of protein complexes and their cooperative regulation in protein function is a key feature in many biological systems. The synergistic regulation in different subunits often enhances the functional properties of the multi-enzyme complex. The present study used molecular dynamics and Brownian dynamics simulations to study the effects of allostery, oligomerization and intermediate channeling on enhancing the protein function of tryptophan synthase (TRPS. TRPS uses a set of α/β-dimeric units to catalyze the last two steps of L-tryptophan biosynthesis, and the rate is remarkably slower in the isolated monomers. Our work shows that without their binding partner, the isolated monomers are stable and more rigid. The substrates can form fairly stable interactions with the protein in both forms when the protein reaches the final ligand-bound conformations. Our simulations also revealed that the α/β-dimeric unit stabilizes the substrate-protein conformation in the ligand binding process, which lowers the conformation transition barrier and helps the protein conformations shift from an open/inactive form to a closed/active form. Brownian dynamics simulations with a coarse-grained model illustrate how protein conformations affect substrate channeling. The results highlight the complex roles of protein oligomerization and the fine balance between rigidity and dynamics in protein function.

  16. Physiological relevance of plant 2-Cys peroxiredoxin overoxidation level and oligomerization status.

    Science.gov (United States)

    Cerveau, Delphine; Ouahrani, Djelloul; Marok, Mohamed Amine; Blanchard, Laurence; Rey, Pascal

    2016-01-01

    Peroxiredoxins are ubiquitous thioredoxin-dependent peroxidases presumed to display, upon environmental constraints, a chaperone function resulting from a redox-dependent conformational switch. In this work, using biochemical and genetic approaches, we aimed to unravel the factors regulating the redox status and the conformation of the plastidial 2-Cys peroxiredoxin (2-Cys PRX) in plants. In Arabidopsis, we show that in optimal growth conditions, the overoxidation level mainly depends on the availability of thioredoxin-related electron donors, but not on sulfiredoxin, the enzyme reducing the 2-Cys PRX overoxidized form. We also observed that upon various physiological temperature, osmotic and light stress conditions, the overoxidation level and oligomerization status of 2-Cys PRX can moderately vary depending on the constraint type. Further, no major change was noticed regarding protein conformation in water-stressed Arabidopsis, barley and potato plants, whereas species-dependent up- and down-variations in overoxidation were observed. In contrast, both 2-Cys PRX overoxidation and oligomerization were strongly induced during a severe oxidative stress generated by methyl viologen. From these data, revealing that the oligomerization status of plant 2-Cys PRX does not exhibit important variation and is not tightly linked to the protein redox status upon physiologically relevant environmental constraints, the possible in planta functions of 2-Cys PRX are discussed. © 2015 John Wiley & Sons Ltd.

  17. Casp8p41: The Protean Mediator of Death in CD4 T-cells that Replicate HIV

    Directory of Open Access Journals (Sweden)

    Rahul Sampath

    2016-01-01

    Full Text Available HIV cure is now the focus of intense research after Timothy Ray Brown (the Berlin patient set the precedent of being the first and only person cured. A major barrier to achieving this goal on a meaningful scale is an elimination of the latent reservoir, which is thought to comprise CD4-positive cells that harbor integrated, replication-competent HIV provirus. These cells do not express viral proteins, are indistinguishable from uninfected CD4 cells, and are thought to be responsible for HIV viral rebound–-that occurs within weeks of combination anti retroviral therapy (cART interruption. Modalities to engineer transcriptional stimulation (reactivation of this dormant integrated HIV provirus, leading to expression of cytotoxic viral proteins, are thought to be a specific way to eradicate the latently infected CD4 pool and are becoming increasingly relevant in the era of HIV cure. HIV protease is one such protein produced after HIV reactivation that cleaves procaspase-8 to generate a novel protein Casp8p41. Casp8p41 then binds to the BH3 domain of BAK, leading to BAK oligomerization, mitochondrial depolarization, and apoptosis. In central memory T cells (TCMs from HIV-infected patients, an elevated Bcl-2/procaspase-8 ratio was observed, and Casp8p41 binding to Bcl-2 was associated with a lack of reactivation-induced cell death. This was reversed by priming cells with a specific Bcl-2 antagonist prior to reactivation, resulting in increased cell death and decreased HIV DNA in a Casp8p41-dependent pathway. This review describes the biology, clinical relevance, and implications of Casp8p41 for a potential cure.

  18. 3D Structure and Interaction of p24β and p24δ Golgi Dynamics Domains: Implication for p24 Complex Formation and Cargo Transport.

    Science.gov (United States)

    Nagae, Masamichi; Hirata, Tetsuya; Morita-Matsumoto, Kana; Theiler, Romina; Fujita, Morihisa; Kinoshita, Taroh; Yamaguchi, Yoshiki

    2016-10-09

    The p24 family consists of four subfamilies (p24α, p24β, p24γ, and p24δ), and the proteins are thought to form hetero-oligomeric complexes for efficient transport of cargo proteins from the endoplasmic reticulum to the Golgi apparatus. The proteins possess a conserved luminal Golgi dynamics (GOLD) domain, whose functions are largely unknown. Here, we present structural and biochemical studies of p24β1 and p24δ1 GOLD domains. Use of GOLD domain-deleted mutants revealed that the GOLD domain of p24δ1 is required for proper p24 hetero-oligomeric complex formation and efficient transport of GPI-anchored proteins. The p24β1 and p24δ1 GOLD domains share a common β-sandwich fold with a characteristic intrasheet disulfide bond. The GOLD domain of p24δ1 crystallized as dimers, allowing the analysis of a homophilic interaction site. Surface plasmon resonance and solution NMR analyses revealed that p24β1 and p24δ1 GOLD domains interact weakly (K d = ~10 -4 M). Bi-protein titration provided interaction site maps. We propose that the heterophilic interaction of p24 GOLD domains contributes to the formation of the p24 hetero-oligomeric complex and to efficient cargo transport. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Trusted Domain

    DEFF Research Database (Denmark)

    Hjorth, Theis Solberg; Torbensen, Rune

    2012-01-01

    remote access via IP-based devices such as smartphones. The Trusted Domain platform fits existing legacy technologies by managing their interoperability and access controls, and it seeks to avoid the security issues of relying on third-party servers outside the home. It is a distributed system...... of wireless standards, limited resources of embedded systems, etc. Taking these challenges into account, we present a Trusted Domain home automation platform, which dynamically and securely connects heterogeneous networks of Short-Range Wireless devices via simple non-expert user. interactions, and allows......In the digital age of home automation and with the proliferation of mobile Internet access, the intelligent home and its devices should be accessible at any time from anywhere. There are many challenges such as security, privacy, ease of configuration, incompatible legacy devices, a wealth...

  20. Mutations increasing exposure of a receptor binding site epitope in the soluble and oligomeric forms of the caprine arthritis-encephalitis lentivirus envelope glycoprotein

    International Nuclear Information System (INIS)

    Hoetzel, Isidro; Cheevers, William P.

    2005-01-01

    The caprine arthritis-encephalitis (CAEV) and ovine maedi-visna (MVV) viruses are resistant to antibody neutralization, a feature shared with all other lentiviruses. Whether the CAEV gp135 receptor binding site(s) (RBS) in the functional surface envelope glycoprotein (Env) is protected from antibody binding, allowing the virus to resist neutralization, is not known. Two CAEV gp135 regions were identified by extrapolating a gp135 structural model that could affect binding of antibodies to the RBS: the V1 region and a short sequence analogous in position to the human immunodeficiency virus type 1 gp120 loop B postulated to be located between two major domains of CAEV gp135. Mutation of isoleucine-166 to alanine in the putative loop B of gp135 increased the affinity of soluble gp135 for the CAEV receptor(s) and goat monoclonal antibody (Mab) F7-299 which recognizes an epitope overlapping the gp135 RBS. The I166A mutation also stabilized or exposed the F7-299 epitope in anionic detergent buffers, indicating that the I166A mutation induces conformational changes and stabilizes the RBS of soluble gp135 and enhances Mab F7-299 binding. In contrast, the affinity of a V1 deletion mutant of gp135 for the receptor and Mab F7-299 and its structural stability did not differ from that of the wild-type gp135. However, both the I166A mutation and the V1 deletion of gp135 increased cell-to-cell fusion activity and binding of Mab F7-299 to the oligomeric Env. Therefore, the CAEV gp135 RBS is protected from antibody binding by mechanisms both dependent and independent of Env oligomerization which are disrupted by the V1 deletion and the I166A mutation, respectively. In addition, we found a correlation between side-chain β-branching at amino acid position 166 and binding of Mab F7-299 to oligomeric Env and cell-to-cell fusion, suggesting local secondary structure constraints in the region around isoleucine-166 as one determinant of gp135 RBS exposure and antibody binding

  1. Insights into Basal Signaling Regulation, Oligomerization, and Structural Organization of the Human G-Protein Coupled Receptor 83.

    Directory of Open Access Journals (Sweden)

    Anne Müller

    Full Text Available The murine G-protein coupled receptor 83 (mGPR83 is expressed in the hypothalamus and was previously suggested to be involved in the regulation of metabolism. The neuropeptide PEN has been recently identified as a potent GPR83 ligand. Moreover, GPR83 constitutes functionally relevant hetero-oligomers with other G-protein coupled receptors (GPCR such as the ghrelin receptor (GHSR or GPR171. Previous deletion studies also revealed that the long N-terminal extracellular receptor domain (eNDo of mGPR83 may act as an intra-molecular ligand, which participates in the regulation of basal signaling activity, which is a key feature of GPCR function. Here, we investigated particular amino acids at the eNDo of human GPR83 (hGPR83 by side-directed mutagenesis to identify determinants of the internal ligand. These studies were accompanied by structure homology modeling to combine functional insights with structural information. The capacity for hetero-oligomer formation of hGPR83 with diverse family A GPCRs such as the melanocortin-4 receptor (MC4R was also investigated, with a specific emphasis on the impact of the eNDo on oligomerization and basal signaling properties. Finally, we demonstrate that hGPR83 exhibits an unusual basal signaling for different effectors, which also supports signaling promiscuity. hGPR83 interacts with a variety of hypothalamic GPCRs such as the MC4R or GHSR. These interactions are not dependent on the ectodomain and most likely occur at interfaces constituted in the transmembrane regions. Moreover, several amino acids at the transition between the eNDo and transmembrane helix 1 were identified, where mutations lead also to biased basal signaling modulation.

  2. The Apoptosome: Heart and Soul of the Cell Death Machine

    Directory of Open Access Journals (Sweden)

    Arul M. Chinnaiyan

    1999-04-01

    Full Text Available Apoptosis is a fundamental biologic process by which metazoan cells orchestrate their own self-demise. Genetic analyses of the nematode C elegans identified three core components of the suicide apparatus which include CED-3, CED-4, and CED-9. An analogous set of core constituents exists in mammalian cells and includes caspase-9, Apaf-1, and bcl-2/xL, respectively. CED-3 and CED-4, along with their mammalian counterparts, function to kill cells, whereas CED-9 and its mammalian equivalents protect cells from death. These central components biochemically intermingle in a ternary complex recently dubbed the “apoptosome.” The C elegans protein EGL-1 and its mammalian counterparts, pro-apoptotic members of the bcl-2 family, induce cell death by disrupting apoptosome interactions. Thus, EGL-1 may represent a primordial signal integrator for the apoptosome. Various biochemical processes including oligomerization, adenosine triphosphate ATP/dATP binding, and cytochrome c interaction play a role in regulating the ternary death complex. Recent studies suggest that cell death receptors, such as CD95, may amplify their suicide signal by activating the apoptosome. These mutual associations by core components of the suicide apparatus provide a molecular framework in which diverse death signals likely interface. Understanding the apoptosome and its cellular connections will facilitate the design of novel therapeutic strategies for cancer and other disease states in which apoptosis plays a pivotal role.

  3. Modelling the interdependence between the stoichiometry of receptor oligomerization and ligand binding for a coexisting dimer/tetramer receptor system.

    Science.gov (United States)

    Rovira, X; Vivó, M; Serra, J; Roche, D; Strange, P G; Giraldo, J

    2009-01-01

    Many G protein-coupled receptors have been shown to exist as oligomers, but the oligomerization state and the effects of this on receptor function are unclear. For some G protein-coupled receptors, in ligand binding assays, different radioligands provide different maximal binding capacities. Here we have developed mathematical models for co-expressed dimeric and tetrameric species of receptors. We have considered models where the dimers and tetramers are in equilibrium and where they do not interconvert and we have also considered the potential influence of the ligands on the degree of oligomerization. By analogy with agonist efficacy, we have considered ligands that promote, inhibit or have no effect on oligomerization. Cell surface receptor expression and the intrinsic capacity of receptors to oligomerize are quantitative parameters of the equations. The models can account for differences in the maximal binding capacities of radioligands in different preparations of receptors and provide a conceptual framework for simulation and data fitting in complex oligomeric receptor situations.

  4. N-Glycosylation instead of cholesterol mediates oligomerization and apical sorting of GPI-APs in FRT cells.

    Science.gov (United States)

    Imjeti, Naga Salaija; Lebreton, Stéphanie; Paladino, Simona; de la Fuente, Erwin; Gonzalez, Alfonso; Zurzolo, Chiara

    2011-12-01

    Sorting of glycosylphosphatidyl-inositol--anchored proteins (GPI-APs) in polarized epithelial cells is not fully understood. Oligomerization in the Golgi complex has emerged as the crucial event driving apical segregation of GPI-APs in two different kind of epithelial cells, Madin-Darby canine kidney (MDCK) and Fisher rat thyroid (FRT) cells, but whether the mechanism is conserved is unknown. In MDCK cells cholesterol promotes GPI-AP oligomerization, as well as apical sorting of GPI-APs. Here we show that FRT cells lack this cholesterol-driven oligomerization as apical sorting mechanism. In these cells both apical and basolateral GPI-APs display restricted diffusion in the Golgi likely due to a cholesterol-enriched membrane environment. It is striking that N-glycosylation is the critical event for oligomerization and apical sorting of GPI-APs in FRT cells but not in MDCK cells. Our data indicate that at least two mechanisms exist to determine oligomerization in the Golgi leading to apical sorting of GPI-APs. One depends on cholesterol, and the other depends on N-glycosylation and is insensitive to cholesterol addition or depletion.

  5. The Leishmania donovani UMP Synthase Is Essential for Promastigote Viability and Has an Unusual Tetrameric Structure That Exhibits Substrate-controlled Oligomerization

    Energy Technology Data Exchange (ETDEWEB)

    French, Jarrod B.; Yates, Phillip A.; Soysa, D.Radika; Boitz, Jan M.; Carter, Nicola S.; Chang, Bailey; Ullman, Buddy; Ealick, Steven E. (Oregon HSU); (Cornell)

    2011-08-09

    The final two steps of de novo uridine 5'-monophosphate (UMP) biosynthesis are catalyzed by orotate phosphoribosyltransferase (OPRT) and orotidine 5'-monophosphate decarboxylase (OMPDC). In most prokaryotes and simple eukaryotes these two enzymes are encoded by separate genes, whereas in mammals they are expressed as a bifunctional gene product called UMP synthase (UMPS), with OPRT at the N terminus and OMPDC at the C terminus. Leishmania and some closely related organisms also express a bifunctional enzyme for these two steps, but the domain order is reversed relative to mammalian UMPS. In this work we demonstrate that L. donovani UMPS (LdUMPS) is an essential enzyme in promastigotes and that it is sequestered in the parasite glycosome. We also present the crystal structure of the LdUMPS in complex with its product, UMP. This structure reveals an unusual tetramer with two head to head and two tail to tail interactions, resulting in two dimeric OMPDC and two dimeric OPRT functional domains. In addition, we provide structural and biochemical evidence that oligomerization of LdUMPS is controlled by product binding at the OPRT active site. We propose a model for the assembly of the catalytically relevant LdUMPS tetramer and discuss the implications for the structure of mammalian UMPS.

  6. The role of surface electrostatics on the stability, function and regulation of human cystathionine β-synthase, a complex multidomain and oligomeric protein.

    Science.gov (United States)

    Pey, Angel L; Majtan, Tomas; Kraus, Jan P

    2014-09-01

    Human cystathionine β-synthase (hCBS) is a key enzyme of sulfur amino acid metabolism, controlling the commitment of homocysteine to the transsulfuration pathway and antioxidant defense. Mutations in hCBS cause inherited homocystinuria (HCU), a rare inborn error of metabolism characterized by accumulation of toxic homocysteine in blood and urine. hCBS is a complex multidomain and oligomeric protein whose activity and stability are independently regulated by the binding of S-adenosyl-methionine (SAM) to two different types of sites at its C-terminal regulatory domain. Here we study the role of surface electrostatics on the complex regulation and stability of hCBS using biophysical and biochemical procedures. We show that the kinetic stability of the catalytic and regulatory domains is significantly affected by the modulation of surface electrostatics through noticeable structural and energetic changes along their denaturation pathways. We also show that surface electrostatics strongly affect SAM binding properties to those sites responsible for either enzyme activation or kinetic stabilization. Our results provide new insight into the regulation of hCBS activity and stability in vivo with implications for understanding HCU as a conformational disease. We also lend experimental support to the role of electrostatic interactions in the recently proposed binding modes of SAM leading to hCBS activation and kinetic stabilization. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Elucidation of amyloid beta-protein oligomerization mechanisms: discrete molecular dynamics study.

    Science.gov (United States)

    Urbanc, B; Betnel, M; Cruz, L; Bitan, G; Teplow, D B

    2010-03-31

    Oligomers of amyloid beta-protein (Abeta) play a central role in the pathology of Alzheimer's disease. Of the two predominant Abeta alloforms, Abeta(1-40) and Abeta(1-42), Abeta(1-42) is more strongly implicated in the disease. We elucidated the structural characteristics of oligomers of Abeta(1-40) and Abeta(1-42) and their Arctic mutants, [E22G]Abeta(1-40) and [E22G]Abeta(1-42). We simulated oligomer formation using discrete molecular dynamics (DMD) with a four-bead protein model, backbone hydrogen bonding, and residue-specific interactions due to effective hydropathy and charge. For all four peptides under study, we derived the characteristic oligomer size distributions that were in agreement with prior experimental findings. Unlike Abeta(1-40), Abeta(1-42) had a high propensity to form paranuclei (pentameric or hexameric) structures that could self-associate into higher-order oligomers. Neither of the Arctic mutants formed higher-order oligomers, but [E22G]Abeta(1-40) formed paranuclei with a similar propensity to that of Abeta(1-42). Whereas the best agreement with the experimental data was obtained when the charged residues were modeled as solely hydrophilic, further assembly from spherical oligomers into elongated protofibrils was induced by nonzero electrostatic interactions among the charged residues. Structural analysis revealed that the C-terminal region played a dominant role in Abeta(1-42) oligomer formation whereas Abeta(1-40) oligomerization was primarily driven by intermolecular interactions among the central hydrophobic regions. The N-terminal region A2-F4 played a prominent role in Abeta(1-40) oligomerization but did not contribute to the oligomerization of Abeta(1-42) or the Arctic mutants. The oligomer structure of both Arctic peptides resembled Abeta(1-42) more than Abeta(1-40), consistent with their potentially more toxic nature.

  8. The effects of oligomerization on Saccharomyces cerevisiae Mcm4/6/7 function

    Directory of Open Access Journals (Sweden)

    Davey Megan J

    2010-09-01

    Full Text Available Abstract Background Minichromosome maintenance proteins (Mcm 2, 3, 4, 5, 6 and 7 are related by sequence and form a variety of complexes that unwind DNA, including Mcm4/6/7. A Mcm4/6/7 trimer forms one half of the Mcm2-7 hexameric ring and can be thought of as the catalytic core of Mcm2-7, the replicative helicase in eukaryotic cells. Oligomeric analysis of Mcm4/6/7 suggests that it forms a hexamer containing two Mcm4/6/7 trimers, however, under certain conditions trimeric Mcm4/6/7 has also been observed. The functional significance of the different Mcm4/6/7 oligomeric states has not been assessed. The results of such an assessment would have implications for studies of both Mcm4/6/7 and Mcm2-7. Results Here, we show that Saccharomyces cerevisiae Mcm4/6/7 reconstituted from individual subunits exists in an equilibrium of oligomeric forms in which smaller oligomers predominate in the absence of ATP. In addition, we found that ATP, which is required for Mcm4/6/7 activity, shifts the equilibrium towards larger oligomers, likely hexamers of Mcm4/6/7. ATPγS and to a lesser extent ADP also shift the equilibrium towards hexamers. Study of Mcm4/6/7 complexes containing mutations that interfere with the formation of inter-subunit ATP sites (arginine finger mutants indicates that full activity of Mcm4/6/7 requires all of its ATP sites, which are formed in a hexamer and not a trimer. In keeping with this observation, Mcm4/6/7 binds DNA as a hexamer. Conclusions The minimal functional unit of Mcm4/6/7 is a hexamer. One of the roles of ATP binding by Mcm4/6/7 may be to stabilize formation of hexamers.

  9. Single-molecule diffusometry reveals the nucleotide-dependent oligomerization pathways of Nicotiana tabacum Rubisco activase

    Science.gov (United States)

    Wang, Quan; Serban, Andrew J.; Wachter, Rebekka M.; Moerner, W. E.

    2018-03-01

    Oligomerization plays an important role in the function of many proteins, but a quantitative picture of the oligomer distribution has been difficult to obtain using existing techniques. Here we describe a method that combines sub-stoichiometric labeling and recently developed single-molecule diffusometry to measure the size distribution of oligomers under equilibrium conditions in solution, one molecule at a time. We use this technique to characterize the oligomerization behavior of Nicotiana tabacum (Nt) Rubisco activase (Nt-Rca), a chaperone-like AAA-plus ATPase essential in regulating carbon fixation during photosynthesis. We directly observed monomers, dimers, and a tetramer/hexamer mixture and extracted their fractional abundance as a function of protein concentration. We show that the oligomerization pathway of Nt-Rca is nucleotide dependent: ATPγS binding strongly promotes tetramer/hexamer formation from dimers and results in a preferred tetramer/hexamer population for concentrations in the 1-10 μM range. Furthermore, we directly observed dynamic assembly and disassembly processes of single complexes in real time and from there estimated the rate of subunit exchange to be ˜0.1 s-1 with ATPγS. On the other hand, ADP binding destabilizes Rca complexes by enhancing the rate of subunit exchange by >2 fold. These observations provide a quantitative starting point to elucidate the structure-function relations of Nt-Rca complexes. We envision the method to fill a critical gap in defining and quantifying protein assembly pathways in the small-oligomer regime.

  10. Polyhedral oligomeric silsequioxane monolayer as a nanoporous interlayer for preparation of low-k dielectric films

    International Nuclear Information System (INIS)

    Liu, Y-L; Liu, C-S; Cho, C-I; Hwu, M-J

    2007-01-01

    Polyhedral oligomeric silsequioxane (POSS) monomer was fixed to a silicon surface by reacting octakis(glycidyldimethylsiloxy)octasilsesquioxane (OG-POSS) with the OH-terminated silicon surface in the presence of tin (II) chloride. The POSS cage layer then served as a nanoporous interlayer to reduce the dielectric constants of polyimide films on silicon surfaces. The chemical structure and surface morphology of OG-POSS modified silicon surfaces were characterized with XPS. With the introduction of a POSS nanopored interlayer, the dielectric constants of polyimide films were reduced

  11. Thermo-mechanical characterization of a monochlorophenyl, hepta isobutyl polyhedral oligomeric silsesquioxane/polystyrene composite

    International Nuclear Information System (INIS)

    Blanco, Ignazio; Bottino, Francesco A.; Cicala, Gianluca; Cozzo, Giulia; Latteri, Alberta; Recca, Antonino

    2014-01-01

    The thermal and mechanical properties of a monochlorophenyl, hepta isobutyl Polyhedral Oligomeric Silsesquioxane/Polystyrene (ph,hib-POSS/PS) composite were studied and compared with those of pristine polymer. ph,hib-POSS/PS system was prepared by solubilization and precipitation of Polystyrene (PS) in the presence of POSS. Scanning Electron Microscopy (SEM) was performed to check the distribution of the filler in the polymer matrix. Dynamic Mechanical Analysis (DMA) was carried out to measure viscoelastic properties of solid samples. Degradations were carried out into a thermobalance and the obtained thermogravimetric (TG) and differential thermogravimetric (DTG) curves were discussed and interpreted

  12. Protic ionic liquids based on the dimeric and oligomeric anions: [(AcO)xH(x-1)]-.

    Science.gov (United States)

    Johansson, K M; Izgorodina, E I; Forsyth, M; MacFarlane, D R; Seddon, K R

    2008-05-28

    We describe a fluidity and conductivity study as a function of composition in N-methylpyrrolidine-acetic acid mixtures. The simple 1 : 1 acid-base mixture appears to form an ionic liquid, but its degree of ionicity is quite low and such liquids are better thought of as poorly dissociated mixtures of acid and base. The composition consisting of 3 moles acetic acid and 1 mole N-methylpyrrolidine is shown to form the highest ionicity mixture in this binary due to the presence of oligomeric anionic species [(AcO)(x)H(x-1)](-) stabilised by hydrogen bonds. These oligomeric species, being weaker bases than the acetate anion, shift the proton transfer equilibrium towards formation of ionic species, thus generating a higher degree of ionicity than is present at the 1 : 1 composition. A Walden plot analysis, thermogravimetric behaviour and proton NMR data, as well as ab initio calculations of the oligomeric species, all support this conclusion.

  13. .Gov Domains API

    Data.gov (United States)

    General Services Administration — This dataset offers the list of all .gov domains, including state, local, and tribal .gov domains. It does not include .mil domains, or other federal domains outside...

  14. National Death Index

    Data.gov (United States)

    U.S. Department of Health & Human Services — The National Death Index (NDI) is a centralized database of death record information on file in state vital statistics offices. Working with these state offices, the...

  15. God's dominion over death.

    Science.gov (United States)

    Schulling, Sharon

    2012-01-01

    This article briefly overviews the criteria for and physiological process of death, contrasting physical death with biblical passages revealing how God interceded in this universal process when Jesus was on earth.

  16. Direct Evidence of Intrinsic Blue Fluorescence from Oligomeric Interfaces of Human Serum Albumin.

    Science.gov (United States)

    Bhattacharya, Arpan; Bhowmik, Soumitra; Singh, Amit K; Kodgire, Prashant; Das, Apurba K; Mukherjee, Tushar Kanti

    2017-10-10

    The molecular origin behind the concentration-dependent intrinsic blue fluorescence of human serum albumin (HSA) is not known yet. This unusual blue fluorescence is believed to be a characteristic feature of amyloid-like fibrils of protein/peptide and originates due to the delocalization of peptide bond electrons through the extended hydrogen bond networks of cross-β-sheet structure. Herein, by combining the results of spectroscopy, size exclusion chromatography, native gel electrophoresis, and confocal microscopy, we have shown that the intrinsic blue fluorescence of HSA exclusively originates from oligomeric interfaces devoid of any amyloid-like fibrillar structure. Our study suggests that this low energy fluorescence band is not due to any particular residue/sequence, but rather it is a common feature of self-assembled peptide bonds. The present findings of intrinsic blue fluorescence from oligomeric interfaces pave the way for future applications of this unique visual phenomenon for early stage detection of various protein aggregation related human diseases.

  17. Oligomerization of glycine and alanine catalyzed by iron oxides: implications for prebiotic chemistry.

    Science.gov (United States)

    Shanker, Uma; Bhushan, Brij; Bhattacharjee, G; Kamaluddin

    2012-02-01

    Iron oxide minerals are probable constituents of the sediments present in geothermal regions of the primitive earth. They might have adsorbed different organic monomers (amino acids, nucleotides etc.) and catalyzed polymerization processes leading to the formation of the first living cell. In the present work we tested the catalytic activity of three forms of iron oxides (Goethite, Akaganeite and Hematite) in the intermolecular condensation of each of the amino acids glycine and L-alanine. The effect of zinc oxide and titanium dioxide on the oligomerization has also been studied. Oligomerization studies were performed for 35 days at three different temperatures 50, 90 and 120°C without applying drying/wetting cycling. The products formed were characterized by HPLC and ESI-MS techniques. All three forms of iron oxides catalyzed peptide bond formation (23.2% of gly2 and 10.65% of ala2). The reaction was monitored every 7 days. Formation of peptides was observed to start after 7 days at 50°C. Maximum yield of peptides was found after 35 days at 90°C. Reaction at 120°C favors formation of diketopiperazine derivatives. It is also important to note that after 35 days of reaction, goethite produced dimer and trimer with the highest yield among the oxides tested. We suggest that the activity of goethite could probably be due to its high surface area and surface acidity.

  18. Phosphate and HEPES buffers potently affect the fibrillation and oligomerization mechanism of Alzheimer's Aβ peptide

    International Nuclear Information System (INIS)

    Garvey, Megan; Tepper, Katharina; Haupt, Caroline; Knuepfer, Uwe; Klement, Karolin; Meinhardt, Jessica; Horn, Uwe; Balbach, Jochen; Faendrich, Marcus

    2011-01-01

    Highlights: → Sodium phosphate buffer accelerated Aβ(1-40) nucleation relative to HEPES. → Aβ(1-40) fibrils formed in the two buffers show only minor structural differences. → NMR revealed that Aβ(1-40) histidine residues mediate buffer dependent changes. -- Abstract: The oligomerization of Aβ peptide into amyloid fibrils is a hallmark of Alzheimer's disease. Due to its biological relevance, phosphate is the most commonly used buffer system for studying the formation of Aβ and other amyloid fibrils. Investigation into the characteristics and formation of amyloid fibrils frequently relies upon material formed in vitro, predominantly in phosphate buffers. Herein, we examine the effects on the fibrillation and oligomerization mechanism of Aβ peptide that occur due solely to the influence of phosphate buffer. We reveal that significant differences in amyloid fibrillation are observed due to fibrillation being initiated in phosphate or HEPES buffer (at physiological pH and temperature). Except for the differing buffer ions, all experimental parameters were kept constant. Fibril formation was assessed using fluorescently monitored kinetic studies, microscopy, X-ray fiber diffraction and infrared and nuclear magnetic resonance spectroscopies. Based on this set up, we herein reveal profound effects on the mechanism and speed of Aβ fibrillation. The three histidine residues at positions 6, 13 and 14 of Aβ(1-40) are instrumental in these mechanistic changes. We conclude that buffer plays a more significant role in fibril formation than has been generally acknowledged.

  19. Multicoil2: predicting coiled coils and their oligomerization states from sequence in the twilight zone.

    Directory of Open Access Journals (Sweden)

    Jason Trigg

    Full Text Available The alpha-helical coiled coil can adopt a variety of topologies, among the most common of which are parallel and antiparallel dimers and trimers. We present Multicoil2, an algorithm that predicts both the location and oligomerization state (two versus three helices of coiled coils in protein sequences. Multicoil2 combines the pairwise correlations of the previous Multicoil method with the flexibility of Hidden Markov Models (HMMs in a Markov Random Field (MRF. The resulting algorithm integrates sequence features, including pairwise interactions, through multinomial logistic regression to devise an optimized scoring function for distinguishing dimer, trimer and non-coiled-coil oligomerization states; this scoring function is used to produce Markov Random Field potentials that incorporate pairwise correlations localized in sequence. Multicoil2 significantly improves both coiled-coil detection and dimer versus trimer state prediction over the original Multicoil algorithm retrained on a newly-constructed database of coiled-coil sequences. The new database, comprised of 2,105 sequences containing 124,088 residues, includes reliable structural annotations based on experimental data in the literature. Notably, the enhanced performance of Multicoil2 is evident when tested in stringent leave-family-out cross-validation on the new database, reflecting expected performance on challenging new prediction targets that have minimal sequence similarity to known coiled-coil families. The Multicoil2 program and training database are available for download from http://multicoil2.csail.mit.edu.

  20. Catalysis of the Oligomerization of O-Phospho-Serine, Aspartic Acid, or Glutamic Acid by Cationic Micelles

    Science.gov (United States)

    Bohler, Christof; Hill, Aubrey R., Jr.; Orgel, Leslie E.

    1996-01-01

    Treatment of relatively concentrated aqueous solutions of 0-phospho-serine (50 mM), aspartic acid (100 mM) or glutamic acid (100 mM) with carbonyldiimidazole leads to the formation of an activated intermediate that oligomerizes efficiently. When the concentration of amino acid is reduced tenfold, few long oligomers can be detected. Positively-charged cetyltrimethyl ammonium bromide micelles concentrate the negatively-charged activated intermediates of the amino acids at their surfaces and catalyze efficient oligomerization even from dilute solutions.

  1. Catalytic Oligomerization of Terminal Alkynes by Lanthanide Carbyls (η5-C5Me5)2LnCH(SiMe3)2 (Ln = Y, La, Ce)

    NARCIS (Netherlands)

    Heeres, H.J.; Teuben, J.H.

    1991-01-01

    Lanthanide and group 3 carbyls Cp*2LnCH(SiMe3)2 (1, Ln = Y; 2, Ln = La; 3, Ln = Ce) are active catalyst precursors for the oligomerization of terminal alkynes HC≡CR (R = alkyl, aryl, SiMe3). The regioselectivity and the extent of oligomerization depend strongly on the lanthanide applied as well as

  2. Identity after Death

    DEFF Research Database (Denmark)

    Gerstrøm, Anna

    2015-01-01

    Purpose: The purpose of this paper is to explore how legacy organizational identity and death relate to each other and, thereby, contribute to closing the gap in knowledge on organizational identity constructions in times of death. Design/methodology/approach: The paper opted for an exploratory....../value: This paper addresses an apparent gap in the literature on identity and death; exploring identity narratives in a bankrupted bank, the paper considers constructions of legacy organizational identities in times of disruptive death....

  3. Sudden death victims

    NARCIS (Netherlands)

    Ceelen, Manon; van der Werf, Christian; Hendrix, Anneke; Naujocks, Tatjana; Woonink, Frits; de Vries, Philip; van der Wal, Allard; Das, Kees

    2015-01-01

    The goal of this study was to ascertain accordance between cause of death established by the forensic physician and autopsy results in young sudden death victims in the Netherlands. Sudden death victims aged 1-45 years examined by forensic physicians operating in the participating regions which also

  4. Death and Grief

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Death and Grief KidsHealth / For Teens / Death and Grief What's in this article? What Is ... the reaction we have in response to a death or loss. Grief can affect our body, mind, ...

  5. Eyelid closure at death

    Directory of Open Access Journals (Sweden)

    A D Macleod

    2009-01-01

    Full Text Available Aim: To observe the incidence of full or partial eyelid closure at death. Materials and Methods: The presence of ptosis was recorded in 100 consecutive hospice patient deaths. Results: Majority (63% of the patients died with their eyes fully closed, however, 37% had bilateral ptosis at death, with incomplete eye closure. In this study, central nervous system tumor involvement and/or acute hepatic encephalopathy appeared to be pre-mortem risk factors of bilateral ptosis at death. Conclusion: Organicity and not psychogenicity is, therefore, the likely etiology of failure of full eyelid closure at death.

  6. Regulator of G Protein Signaling 7 (RGS7) Can Exist in a Homo-oligomeric Form That Is Regulated by Gαo and R7-binding Protein.

    Science.gov (United States)

    Tayou, Junior; Wang, Qiang; Jang, Geeng-Fu; Pronin, Alexey N; Orlandi, Cesare; Martemyanov, Kirill A; Crabb, John W; Slepak, Vladlen Z

    2016-04-22

    RGS (regulator of G protein signaling) proteins of the R7 subfamily (RGS6, -7, -9, and -11) are highly expressed in neurons where they regulate many physiological processes. R7 RGS proteins contain several distinct domains and form obligatory dimers with the atypical Gβ subunit, Gβ5 They also interact with other proteins such as R7-binding protein, R9-anchoring protein, and the orphan receptors GPR158 and GPR179. These interactions facilitate plasma membrane targeting and stability of R7 proteins and modulate their activity. Here, we investigated RGS7 complexes using in situ chemical cross-linking. We found that in mouse brain and transfected cells cross-linking causes formation of distinct RGS7 complexes. One of the products had the apparent molecular mass of ∼150 kDa on SDS-PAGE and did not contain Gβ5 Mass spectrometry analysis showed no other proteins to be present within the 150-kDa complex in the amount close to stoichiometric with RGS7. This finding suggested that RGS7 could form a homo-oligomer. Indeed, co-immunoprecipitation of differentially tagged RGS7 constructs, with or without chemical cross-linking, demonstrated RGS7 self-association. RGS7-RGS7 interaction required the DEP domain but not the RGS and DHEX domains or the Gβ5 subunit. Using transfected cells and knock-out mice, we demonstrated that R7-binding protein had a strong inhibitory effect on homo-oligomerization of RGS7. In contrast, our data indicated that GPR158 could bind to the RGS7 homo-oligomer without causing its dissociation. Co-expression of constitutively active Gαo prevented the RGS7-RGS7 interaction. These results reveal the existence of RGS protein homo-oligomers and show regulation of their assembly by R7 RGS-binding partners. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Oligomeric recombinant H5 HA1 vaccine produced in bacteria protects ferrets from homologous and heterologous wild-type H5N1 influenza challenge and controls viral loads better than subunit H5N1 vaccine by eliciting high-affinity antibodies.

    Science.gov (United States)

    Verma, Swati; Dimitrova, Milena; Munjal, Ashok; Fontana, Juan; Crevar, Corey J; Carter, Donald M; Ross, Ted M; Khurana, Surender; Golding, Hana

    2012-11-01

    Recombinant hemagglutinin from influenza viruses with pandemic potential can be produced rapidly in various cell substrates. In this study, we compared the functionality and immunogenicity of bacterially produced oligomeric or monomeric HA1 proteins from H5N1 (A/Vietnam/1203/04) with those of the egg-based licensed subunit H5N1 (SU-H5N1) vaccine in ferrets challenged with homologous or heterologous H5N1 highly pathogenic influenza strains. Ferrets were vaccinated twice with the oligomeric or monomeric rHA1 or with SU-H5N1 (Sanofi Pasteur) emulsified with Titermax adjuvant and were challenged with wild-type homologous (A/Vietnam/1203/04; clade 1) or heterologous (A/Whooperswan/Mongolia/244/2005; clade 2.2) virus. Only the oligomeric rHA1 (not the monomeric rHA1) immunogen and the SU-H5N1 vaccine provided protection against the lethality and morbidity of homologous and heterologous highly pathogenic H5N1. Oligomeric rHA1 generated more cross-neutralizing antibodies and higher levels of serum antibody binding to HA1, with stronger avidity and a better IgG/IgM ratio, than monomeric HA1 and SU-H5N1 vaccines, as determined by surface plasmon resonance (SPR). Importantly, viral loads after heterologous H5N1 challenge were more efficiently controlled in ferrets vaccinated with the oligomeric rHA1 immunogen than in SU-H5N1-vaccinated ferrets. The reduction of viral loads in the nasal washes correlated strongly with higher-avidity antibodies to oligomeric rHA1 derived from H5N1 clade 1 and clade 2.2 viruses, as measured by SPR. This is the first study to show the role of antibody avidity for the HA1 globular head domain in reduction of viral loads in the upper respiratory tract, which could significantly reduce viral transmission.

  8. Structure of an isolated unglycosylated antibody CH2 domain

    International Nuclear Information System (INIS)

    Prabakaran, Ponraj; Vu, Bang K.; Gan, Jianhua; Feng, Yang; Dimitrov, Dimiter S.; Ji, Xinhua

    2008-01-01

    The crystal structure of an isolated unglycosylated antibody C H 2 domain has been determined at 1.7 Å resolution. The C H 2 (C H 3 for IgM and IgE) domain of an antibody plays an important role in mediating effector functions and preserving antibody stability. It is the only domain in human immunoglobulins (Igs) which is involved in weak interchain protein–protein interactions with another C H 2 domain solely through sugar moieties. The N-linked glycosylation at Asn297 is conserved in mammalian IgGs as well as in homologous regions of other antibody isotypes. To examine the structural details of the C H 2 domain in the absence of glycosylation and other antibody domains, the crystal structure of an isolated unglycosylated antibody γ1 C H 2 domain was determined at 1.7 Å resolution and compared with corresponding C H 2 structures from intact Fc, IgG and Fc receptor complexes. Furthermore, the oligomeric state of the protein in solution was studied using size-exclusion chromatography. The results suggested that the unglycosylated human antibody C H 2 domain is a monomer and that its structure is similar to that found in the intact Fc, IgG and Fc receptor complex structures. However, certain structural variations were observed in the Fc receptor-binding sites. Owing to its small size, stability and non-immunogenic Ig template, the C H 2-domain structure could be useful for the development by protein design of antibody domains exerting effector functions and/or antigen specificity and as a robust scaffold in protein-engineering applications

  9. Chaperonin of Group I: Oligomeric Spectrum and Biochemical and Biological Implications

    Directory of Open Access Journals (Sweden)

    Silvia Vilasi

    2018-01-01

    Full Text Available Chaperonins play various physiological roles and can also be pathogenic. Elucidation of their structure, e.g., oligomeric status and post-translational modifications (PTM, is necessary to understand their functions and mechanisms of action in health and disease. Group I chaperonins form tetradecamers with two stacked heptameric rings. The tetradecamer is considered the typical functional complex for folding of client polypeptides. However, other forms such as the monomer and oligomers with smaller number of subunits than the classical tetradecamer, also occur in cells. The properties and functions of the monomer and oligomers, and their roles in chaperonin-associated diseases are still incompletely understood. Chaperonin I in eukaryotes occurs in various locations, not just the mitochondrion, which is its canonical place of residence and function. Eukaryotic Chaperonin I, namely Hsp60 (designated HSP60 or HSPD1 in humans has, indeed, been found in the cytosol; the plasma-cell membrane; on the outer surface of cells; in the intercellular space; in biological liquids such as lymph, blood, and cerebrospinal fluid; and in secretions, for instance saliva and urine. Hsp60 has also been found in cell-derived vesicles such as exosomes. The functions of Hsp60 in all these non-canonical locales are still poorly characterized and one of the questions not yet answered is in what form, i.e., monomer or oligomer, is the chaperonin present in these non-canonical locations. In view of the steady increase in interest on chaperonopathies over the last several years, we have studied human HSP60 to determine its role in various diseases, its locations in cells and tissues and migrations in the body, and its post-translational modifications that might have an impact on its location and function. We also carried out experiments to characterize the oligomeric status of extramitochondrial of HSP60 in solution. Here, we provide an overview of our results, focusing on

  10. 78 FR 65561 - D-Glucopyranose, oligomeric, decyl octyl glycosides; Exemption from the Requirement of a Tolerance

    Science.gov (United States)

    2013-11-01

    ... metabolize D-glucopyranose, oligomeric, C 10 -C 16 -alkyl glycosides to water-soluble substances... polyoxyethylene polymers and fatty acids; carriers such as clay and diatomaceous earth; thickeners such as... exposure through drinking water and in residential settings, but does not include occupational exposure...

  11. Regulation of complement by cartilage oligomeric matrix protein allows for a novel molecular diagnostic principle in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Happonen, Kaisa E; Saxne, Tore; Aspberg, Anders

    2010-01-01

    Cartilage oligomeric matrix protein (COMP) is a structural component of cartilage, where it catalyzes collagen fibrillogenesis. Elevated amounts of COMP are found in serum during increased turnover of cartilage associated with active joint disease, such as rheumatoid arthritis (RA) and osteoarthr...

  12. Kinetics in Signal Transduction Pathways Involving Promiscuous Oligomerizing Receptors Can Be Determined by Receptor Specificity : Apoptosis Induction by TRAIL

    NARCIS (Netherlands)

    Szegezdi, Eva; van der Sloot, Almer M.; Mahalingam, Devalingam; O'Leary, Lynda; Cool, Robbert H.; Munoz, Ines G.; Montoya, Guillermo; Quax, Wim J.; de Jong, Steven; Samali, Afshin; Serrano, Luis

    Here we show by computer modeling that kinetics and outcome of signal transduction in case of hetero-oligomerizing receptors of a promiscuous ligand largely depend on the relative amounts of its receptors. Promiscuous ligands can trigger the formation of nonproductive receptor complexes, which slows

  13. Orally administrated cinnamon extract reduces β-amyloid oligomerization and corrects cognitive impairment in Alzheimer's disease animal models.

    Directory of Open Access Journals (Sweden)

    Anat Frydman-Marom

    Full Text Available An increasing body of evidence indicates that accumulation of soluble oligomeric assemblies of β-amyloid polypeptide (Aβ play a key role in Alzheimer's disease (AD pathology. Specifically, 56 kDa oligomeric species were shown to be correlated with impaired cognitive function in AD model mice. Several reports have documented the inhibition of Aβ plaque formation by compounds from natural sources. Yet, evidence for the ability of common edible elements to modulate Aβ oligomerization remains an unmet challenge. Here we identify a natural substance, based on cinnamon extract (CEppt, which markedly inhibits the formation of toxic Aβ oligomers and prevents the toxicity of Aβ on neuronal PC12 cells. When administered to an AD fly model, CEppt rectified their reduced longevity, fully recovered their locomotion defects and totally abolished tetrameric species of Aβ in their brain. Furthermore, oral administration of CEppt to an aggressive AD transgenic mice model led to marked decrease in 56 kDa Aβ oligomers, reduction of plaques and improvement in cognitive behavior. Our results present a novel prophylactic approach for inhibition of toxic oligomeric Aβ species formation in AD through the utilization of a compound that is currently in use in human diet.

  14. Styrene oligomerization as a molecular probe reaction for zeolite acidity: a UV-Vis spectroscopy and DFT study

    NARCIS (Netherlands)

    Buurmans, I.L.C.; Pidko, E.A.; Groot, de J.M.; Stavitski, E.; Santen, van R.A.; Weckhuysen, B.M.

    2010-01-01

    A series of H-ZSM-5 crystallites with different framework Si/Al ratios was studied by analyzing the kinetics and reaction mechanism of the oligomerization of 4-fluorostyrene as molecular probe reaction for Brønsted acidity. The formation of carbocationic species was followed by UV-Vis spectroscopy.

  15. Immobilization of isolated FI catalyst on polyhedral oligomeric silsesquioxane-functionalized silica for the synthesis of weakly entangled polyethylene.

    Science.gov (United States)

    Li, Wei; Yang, Huaqin; Zhang, Jingjing; Mu, Jingshan; Gong, Dirong; Wang, Xiaodong

    2016-09-25

    Polyhedral oligomeric silsesquioxanes (POSSs) were adsorbed on methylaluminoxane-activated silica for the immobilization of fluorinated bis(phenoxyimine)Ti complexes (FI catalyst). These POSSs have been characterized as horizontal spacers isolating the active sites and hindering the chain overlap in polymerization. The heterogeneous catalyst exhibits considerable activity in the synthesis of weakly entangled polyethylene.

  16. Biodegradable and adjustable sol-gel glass based hybrid scaffolds from multi-armed oligomeric building blocks.

    Science.gov (United States)

    Kascholke, Christian; Hendrikx, Stephan; Flath, Tobias; Kuzmenka, Dzmitry; Dörfler, Hans-Martin; Schumann, Dirk; Gressenbuch, Mathias; Schulze, F Peter; Schulz-Siegmund, Michaela; Hacker, Michael C

    2017-11-01

    Biodegradability is a crucial characteristic to improve the clinical potential of sol-gel-derived glass materials. To this end, a set of degradable organic/inorganic class II hybrids from a tetraethoxysilane(TEOS)-derived silica sol and oligovalent cross-linker oligomers containing oligo(d,l-lactide) domains was developed and characterized. A series of 18 oligomers (Mn: 1100-3200Da) with different degrees of ethoxylation and varying length of oligoester units was established and chemical composition was determined. Applicability of an established indirect rapid prototyping method enabled fabrication of a total of 85 different hybrid scaffold formulations from 3-isocyanatopropyltriethoxysilane-functionalized macromers. In vitro degradation was analyzed over 12months and a continuous linear weight loss (0.2-0.5wt%/d) combined with only moderate material swelling was detected which was controlled by oligo(lactide) content and matrix hydrophilicity. Compressive strength (2-30MPa) and compressive modulus (44-716MPa) were determined and total content, oligo(ethylene oxide) content, oligo(lactide) content and molecular weight of the oligomeric cross-linkers as well as material porosity were identified as the main factors determining hybrid mechanics. Cytocompatibility was assessed by cell culture experiments with human adipose tissue-derived stem cells (hASC). Cell migration into the entire scaffold pore network was indicated and continuous proliferation over 14days was found. ALP activity linearly increased over 2weeks indicating osteogenic differentiation. The presented glass-based hybrid concept with precisely adjustable material properties holds promise for regenerative purposes. Adaption of degradation kinetics toward physiological relevance is still an unmet challenge of (bio-)glass engineering. We therefore present a glass-derived hybrid material with adjustable degradation. A flexible design concept based on degradable multi-armed oligomers was combined with an

  17. Human α4β2 nicotinic acetylcholine receptor as a novel target of oligomeric α-synuclein.

    Directory of Open Access Journals (Sweden)

    Qiang Liu

    Full Text Available Cigarette smoking is associated with a decreased incidence of Parkinson disease (PD through unknown mechanisms. Interestingly, a decrease in the numbers of α4β2 nicotinic acetylcholine receptors (α4β2-nAChRs in PD patients suggests an α4β2-nAChR-mediated cholinergic deficit in PD. Although oligomeric forms of α-synuclein have been recognized to be toxic and involved in the pathogenesis of PD, their direct effects on nAChR-mediated cholinergic signaling remains undefined. Here, we report for the first time that oligomeric α-synuclein selectively inhibits human α4β2-nAChR-mediated currents in a dose-dependent, non-competitive and use-independent manner. We show that pre-loading cells with guanyl-5'-yl thiophosphate fails to prevent this inhibition, suggesting that the α-synuclein-induced inhibition of α4β2-nAChR function is not mediated by nAChR internalization. By using a pharmacological approach and cultures expressing transfected human nAChRs, we have shown a clear effect of oligomeric α-synuclein on α4β2-nAChRs, but not on α4β4- or α7-nAChRs, suggesting nAChR subunit selectivity of oligomeric α-synuclein-induced inhibition. In addition, by combining the size exclusion chromatography and atomic force microscopy (AFM analyses, we find that only large (>4 nm oligomeric α-synuclein aggregates (but not monomeric, small oligomeric or fibrillar α-synuclein aggregates exhibit the inhibitory effect on human α4β2-nAChRs. Collectively, we have provided direct evidence that α4β2-nAChR is a sensitive target to mediate oligomeric α-synuclein-induced modulation of cholinergic signaling, and our data imply that therapeutic strategies targeted toward α4β2-nAChRs may have potential for developing new treatments for PD.

  18. Analysis of oligomeric transition of silkworm small heat shock protein sHSP20.8 using high hydrostatic pressure native PAGE

    Science.gov (United States)

    Fujisawa, Tetsuro; Ueda, Toshifumi; Kameyama, Keiichi; Aso, Yoichi; Ishiguro, Ryo

    2013-06-01

    The small heat shock proteins (sHSPs) solubilize thermo-denatured proteins without adenosine triphosphate energy consumption to facilitate protein refolding. sHSP20.8 is one of the silkworm (Bombyx mori) sHSPs having only one cystein in the N-terminal domain: Cys43. We report a simple measurement of oligomeric transition of sHSP20.8 using high hydrostatic pressure native polyacrylamide gel electrophoresis (high hydrostatic pressure (HP) native polyacrylamide gel electrophoresis (PAGE)). At ambient pressure under oxydative condition, the native PAGE of thermal transition of sHSP20.8 oligomer displayed a cooperative association. In contrast, HP native PAGE clearly demonstrated that sHSP20.8 dissociated at 80 MPa and 25°C, and the resultant molecular species gradually reassociated with time under that condition. In addition, the reassociation process was suppressed in the presence of the reductant. These results are consistent with the idea that sHSP20.8 oligomer temporally dissociates at the first thermo-sensing step and reassociates with the oxidation of Cys43.

  19. Inhibiting α-synuclein oligomerization by stable cell-penetrating β-synuclein fragments recovers phenotype of Parkinson's disease model flies.

    Directory of Open Access Journals (Sweden)

    Ronit Shaltiel-Karyo

    Full Text Available The intracellular oligomerization of α-synuclein is associated with Parkinson's disease and appears to be an important target for disease-modifying treatment. Yet, to date, there is no specific inhibitor for this aggregation process. Using unbiased systematic peptide array analysis, we identified molecular interaction domains within the β-synuclein polypeptide that specifically binds α-synuclein. Adding such peptide fragments to α-synuclein significantly reduced both amyloid fibrils and soluble oligomer formation in vitro. A retro-inverso analogue of the best peptide inhibitor was designed to develop the identified molecular recognition module into a drug candidate. While this peptide shows indistinguishable activity as compared to the native peptide, it is stable in mouse serum and penetrates α-synuclein over-expressing cells. The interaction interface between the D-amino acid peptide and α-synuclein was mapped by Nuclear Magnetic Resonance spectroscopy. Finally, administering the retro-inverso peptide to a Drosophila model expressing mutant A53T α-synuclein in the nervous system, resulted in a significant recovery of the behavioral abnormalities of the treated flies and in a significant reduction in α-synuclein accumulation in the brains of the flies. The engineered retro-inverso peptide can serve as a lead for developing a novel class of therapeutic agents to treat Parkinson's disease.

  20. Cartilage oligomeric matrix protein in patients with juvenile idiopathic arthritis: relation to growth and disease activity

    DEFF Research Database (Denmark)

    Bjørnhart, Birgitte; Juul, Anders; Nielsen, Susan

    2009-01-01

    OBJECTIVE: Cartilage oligomeric matrix protein (COMP) has been identified as a prognostic marker of progressive joint destruction in rheumatoid arthritis. In this population based study we evaluated associations between plasma concentrations of COMP, disease activity, and growth velocity...... in patients with recent-onset juvenile idiopathic arthritis (JIA). COMP levels in JIA and healthy children were compared with those in healthy adults. Plasma levels of insulin-like growth factor I (IGF-1), which has been associated with COMP expression and growth velocity, were studied in parallel. METHODS......: 87 patients with JIA entered the study, including oligoarticular JIA (n = 34), enthesitis-related arthritis (n = 8), polyarticular rheumatoid factor (RF)-positive JIA (n = 2), polyarticular RF-negative JIA (n = 27), systemic JIA (n = 6), and undifferentiated JIA (n = 10). Plasma levels of COMP were...

  1. Hedgehog Buckyball: A High-Symmetry Complete Polyhedral Oligomeric Silsesquioxane (POSS

    Directory of Open Access Journals (Sweden)

    Yu Hu

    2016-08-01

    Full Text Available In this study, we report UV-MALDI-TOF MS evidence of a fullerene-like silsesquioxane, a high-symmetry polyhedral oligomeric silsesquioxane (POSS or SSO formulated as R60-Si60O90 or T60 (T = RSiO1.5. The T60 preparation can be performed using a normal hydrolytic condensation of [(3-methacryloxypropyl]trimethoxysilane (MPMS as an example. Theoretically, four 3sp3 hybrid orbitals (each containing an unpaired electron of a Si atom are generated before the bond formation. Then it bonds to another four atom electrons using the four generated hybrid orbitals which produced a stable configuration. This fullerene-like silsesquioxane should exhibit much more functionality, activity and selectivity and is easier to assemble than the double bonds in a fullerene.

  2. Multifunctional Mesoporous Ionic Gels and Scaffolds Derived from Polyhedral Oligomeric Silsesquioxanes.

    Science.gov (United States)

    Lee, Jin Hong; Lee, Albert S; Lee, Jong-Chan; Hong, Soon Man; Hwang, Seung Sang; Koo, Chong Min

    2017-02-01

    A new methodology for fabrication of inorganic-organic hybrid ionogels and scaffolds is developed through facile cross-linking and solution extraction of a newly developed ionic polyhedral oligomeric silsesquioxane with inorganic core. Through design of various cationic tertiary amines, as well as cross-linkable functional groups on each arm of the inorganic core, high-performance ionogels are fabricated with excellent electrochemical stability and unique ion conduction behavior, giving superior lithium ion battery performance. Moreover, through solvent extraction of the liquid components, hybrid scaffolds with well-defined, interconnected mesopores are utilized as heterogeneous catalysts for the CO 2 -catalyzed cycloaddition of epoxides. Excellent catalytic performance, as well as highly efficient recyclability are observed when compared to other previous literature materials.

  3. Efficient light-emitting devices based on platinum-complexes-anchored polyhedral oligomeric silsesquioxane materials

    KAUST Repository

    Yang, Xiaohui

    2010-08-24

    The synthesis, photophysical, and electrochemical characterization of macromolecules, consisting of an emissive platinum complex and carbazole moieties covalently attached to a polyhedral oligomeric silsesquioxane (POSS) core, is reported. Organic light-emitting devices based on these POSS materials exhibit a peak external quantum efficiency of ca. 8%, which is significantly higher than that of the analogous devices with a physical blend of the platinum complexes and a polymer matrix, and they represent noticeable improvement in the device efficiency of solution-processable phosphorescent excimer devices. Furthermore, the ratio of monomer and excimer/aggregate electroluminescent emission intensity, as well as the device efficiency, increases as the platinum complex moiety presence on the POSS macromolecules decreases. © 2010 American Chemical Society.

  4. Flow cytometry evidence of human granulocytes interaction with polyhedral oligomeric silsesquioxanes: effect of nanoparticle charge

    International Nuclear Information System (INIS)

    Renò, Filippo; Rizzi, Manuela; Pittarella, Pamela; Carniato, Fabio; Olivero, Francesco; Marchese, Leonardo

    2013-01-01

    Nanoparticles (NPs) entering the human body are immediately confronted with the innate part of human immune system. In particular, monocyte and neutrophil granulocytes readily clear particles by phagocytosis, even if in the case of NPs the uptake mechanism may be classified as macropinocytosis. Among engineered nanoparticles, in the last years, siliceous materials have emerged as promising materials for several applications ranging from catalysis to biomedical. The polyhedral oligomeric silsesquioxanes (POSS) are nanodimensional, easily synthesizable molecular compounds and POSS-based systems are promising carriers for biological molecules. In this work, the ability of human granulocytes to uptake positively and negatively charged POSS was measured using a simple flow cytometry analysis based on cell size modifications. The data obtained showed that after a 30 min exposure only positive NPs were uptaken by human granulocyte using both macropinocytosis and clathrin-mediated mechanisms as demonstrated by uptake inhibition mediated by amiloride and chlorpromazine. (paper)

  5. Existential Concerns About Death

    DEFF Research Database (Denmark)

    Moestrup, Lene; Hansen, Helle Ploug

    2015-01-01

    psychology or Kübler-Ross’ theory about death stages. The complex concerns might be explained using Martin Heidegger’s phenomenological thinking. We aimed to illuminate dying patients´ existential concerns about the impending death through a descriptive analysis of semi-structured interviews with 17 cancer...... patients in Danish hospices. The main findings demonstrated how the patients faced the forthcoming death without being anxious of death but sorrowful about leaving life. Furthermore, patients expressed that they avoided thinking about death. However, some had reconstructed specific and positive ideas about...... afterlife and made accurate decisions for practical aspects of their death. The patients wished to focus on positive aspects in their daily life at hospice. It hereby seems important to have ongoing reflections and to include different theoretical perspectives when providing existential support to dying...

  6. Structural adaptation of the subunit interface of oligomeric thermophilic and hyperthermophilic enzymes.

    Science.gov (United States)

    Maugini, Elisa; Tronelli, Daniele; Bossa, Francesco; Pascarella, Stefano

    2009-04-01

    Enzymes from thermophilic and, particularly, from hyperthermophilic organisms are surprisingly stable. Understanding of the molecular origin of protein thermostability and thermoactivity attracted the interest of many scientist both for the perspective comprehension of the principles of protein structure and for the possible biotechnological applications through application of protein engineering. Comparative studies at sequence and structure levels were aimed at detecting significant differences of structural parameters related to protein stability between thermophilic and hyperhermophilic structures and their mesophilic homologs. Comparative studies were useful in the identification of a few recurrent themes which the evolution utilized in different combinations in different protein families. These studies were mostly carried out at the monomer level. However, maintenance of a proper quaternary structure is an essential prerequisite for a functional macromolecule. At the environmental temperatures experienced typically by hyper- and thermophiles, the subunit interactions mediated by the interface must be sufficiently stable. Our analysis was therefore aimed at the identification of the molecular strategies adopted by evolution to enhance interface thermostability of oligomeric enzymes. The variation of several structural properties related to protein stability were tested at the subunit interfaces of thermophilic and hyperthermophilic oligomers. The differences of the interface structural features observed between the hyperthermophilic and thermophilic enzymes were compared with the differences of the same properties calculated from pairwise comparisons of oligomeric mesophilic proteins contained in a reference dataset. The significance of the observed differences of structural properties was measured by a t-test. Ion pairs and hydrogen bonds do not vary significantly while hydrophobic contact area increases specially in hyperthermophilic interfaces. Interface

  7. Sudden Infant Death Syndrome (SIDS)

    Science.gov (United States)

    Sudden infant death syndrome (SIDS) Overview Sudden infant death syndrome (SIDS) is the unexplained death, usually during sleep, of a seemingly healthy baby ... year old. SIDS is sometimes known as crib death because the infants often die in their cribs. ...

  8. The Structures of Coiled-Coil Domains from Type III Secretion System Translocators Reveal Homology to Pore-Forming Toxins

    Energy Technology Data Exchange (ETDEWEB)

    Barta, Michael L.; Dickenson, Nicholas E.; Patil, Mrinalini; Keightley, Andrew; Wyckoff, Gerald J.; Picking, William D.; Picking, Wendy L.; Geisbrecht, Brian V. (UMKC); (OKLU)

    2012-03-26

    Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SSs) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is responsible for over one million deaths per year. The Shigella type III secretion apparatus is composed of a basal body spanning both bacterial membranes and an exposed oligomeric needle. Host altering effectors are secreted through this energized unidirectional conduit to promote bacterial invasion. The active needle tip complex of S. flexneri is composed of a tip protein, IpaD, and two pore-forming translocators, IpaB and IpaC. While the atomic structure of IpaD has been elucidated and studied, structural data on the hydrophobic translocators from the T3SS family remain elusive. We present here the crystal structures of a protease-stable fragment identified within the N-terminal regions of IpaB from S. flexneri and SipB from Salmonella enterica serovar Typhimurium determined at 2.1 {angstrom} and 2.8 {angstrom} limiting resolution, respectively. These newly identified domains are composed of extended-length (114 {angstrom} in IpaB and 71 {angstrom} in SipB) coiled-coil motifs that display a high degree of structural homology to one another despite the fact that they share only 21% sequence identity. Further structural comparisons also reveal substantial similarity to the coiled-coil regions of pore-forming proteins from other Gram-negative pathogens, notably, colicin Ia. This suggests that these mechanistically separate and functionally distinct membrane-targeting proteins may have diverged from a common ancestor during the course of pathogen-specific evolutionary events.

  9. Programmed cell death

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The purpose of this conference to provide a multidisciplinary forum for exchange of state-of-the-art information on the role programmed cell death plays in normal development and homeostasis of many organisms. This volume contains abstracts of papers in the following areas: invertebrate development; immunology/neurology; bcl-2 family; biochemistry; programmed cell death in viruses; oncogenesis; vertebrate development; and diseases.

  10. BRAIN DEATH DIAGNOSIS

    Directory of Open Access Journals (Sweden)

    Calixto Machado

    2009-10-01

    Full Text Available Brain death (BD diagnosis should be established based on the following set of principles, i.e. excluding major confusing factors, identifying the cause of coma, determining irreversibility, and precisely testing brainstem reflexes at all levels of the brainstem. Nonetheless, most criteria for BD diagnosis do not mention that this is not the only way of diagnosing death. The Cuban Commission for the Determination of Death has emphasized the aforesaid three possible situations for diagnosing death: a outside intensive care environment (without life support physicians apply the cardio-circulatory and respiratory criteria; b in forensic medicine circumstances, physicians utilize cadaveric signs (they do not even need a stethoscope; c in the intensive care environment (with life support when cardiorespiratory arrest occurs physicians utilize the cardio-circulatory and respiratory criteria. This methodology of diagnosing death, based on finding any of the death signs, is not related to the concept that there are different types of death. The irreversible loss of cardio-circulatory and respiratory functions can only cause death when ischemia and anoxia are prolonged enough to produce an irreversible destruction of the brain. The sign of irreversible loss of brain functions, that is to say BD diagnosis, is fully reviewed.

  11. Sudden cardiac death

    Directory of Open Access Journals (Sweden)

    Neeraj Parakh

    2015-01-01

    Full Text Available Sudden cardiac death is one of the most common cause of mortality worldwide. Despite significant advances in the medical science, there is little improvement in the sudden cardiac death related mortality. Coronary artery disease is the most common etiology behind sudden cardiac death, in the above 40 years population. Even in the apparently healthy population, there is a small percentage of patients dying from sudden cardiac death. Given the large denominator, this small percentage contributes to the largest burden of sudden cardiac death. Identification of this at risk group among the apparently healthy individual is a great challenge for the medical fraternity. This article looks into the causes and methods of preventing SCD and at some of the Indian data. Details of Brugada syndrome, Long QT syndrome, Genetics of SCD are discussed. Recent guidelines on many of these causes are summarised.

  12. Death with dignity

    Science.gov (United States)

    Allmark, P.

    2002-01-01

    The purpose of this article is to develop a conception of death with dignity and to examine whether it is vulnerable to the sort of criticisms that have been made of other conceptions. In this conception "death" is taken to apply to the process of dying; "dignity" is taken to be something that attaches to people because of their personal qualities. In particular, someone lives with dignity if they live well (in accordance with reason, as Aristotle would see it). It follows that health care professionals cannot confer on patients either dignity or death with dignity. They can, however, attempt to ensure that the patient dies without indignity. Indignities are affronts to human dignity, and include such things as serious pain and the exclusion of patients from involvement in decisions about their lives and deaths. This fairly modest conception of death with dignity avoids the traps of being overly subjective or of viewing the sick and helpless as "undignified". PMID:12161582

  13. Death Attitudes and Changes in Existential Outlook in Parents of Vulnerable Newborns.

    Science.gov (United States)

    Barr, Peter

    2015-01-01

    This study is an Actor-Partner Interdependence Model analysis of the relation of death attitudes with changes in outlook in 59 parent couples of neonatal intensive care newborns. Death attitudes effects with changes in outlook were mostly intrapersonal and they mainly occurred in fathers, though between gender differences were not usually significant. Death avoidance and neutral death acquiescence were positive predictors of positive changes in outlook, and fear of death and neutral death acquiescence were respective positive and inverse predictors of negative changes. Multidimensional measures of death attitudes and personal change should be used when studying these domains of psychological functioning.

  14. Computational Study of the Effect of Confinement within Microporous Structures on the Activity and Selectivity of Metallocene Catalysts for Ethylene Oligomerization

    KAUST Repository

    Toulhoat, Hervé; Lontsi Fomena, Mireille; de Bruin, Theodorus

    2011-01-01

    The effect of confinement within some zeolitic structures on the activity and selectivity of metallocene catalysts for the ethylene oligomerization has been investigated using grand canonical Monte Carlo simulations (GCMC). The following zeolite

  15. Suicide on Death Row.

    Science.gov (United States)

    Tartaro, Christine; Lester, David

    2016-11-01

    Despite the level of supervision of inmates on death row, their suicide rate is higher than both the male prison population in the United States and the population of males over the age of 14 in free society. This study presents suicide data for death row inmates from 1978 through 2010. For the years 1978 through 2010, suicide rates on death row were higher than that for the general population of males over the age of 15 and for state prisons for all but 2 years. © 2016 American Academy of Forensic Sciences.

  16. Multiple functions of the von Willebrand Factor A domain in matrilins: secretion, assembly, and proteolysis

    Directory of Open Access Journals (Sweden)

    Kanbe Katsuaki

    2008-06-01

    Full Text Available Abstract The von Willebrand Factor A (vWF A domain is one of the most widely distributed structural modules in cell-matrix adhesive molecules such as intergrins and extracellular matrix proteins. Mutations in the vWF A domain of matrilin-3 cause multiple epiphyseal dysplasia (MED, however the pathological mechanism remains to be determined. Previously we showed that the vWF A domain in matrilin-1 mediates formation of a filamentous matrix network through metal-ion dependent adhesion sites in the domain. Here we show two new functions of the vWF A domain in cartilage-specific matrilins (1 and 3. First, vWF A domain regulates oligomerization of matrilins. Insertion of a vWF A domain into matrilin-3 converts the formation of a mixture of matrilin-3 tetramer, trimer, and dimer into a tetramer only, while deletion of a vWF A domain from matrilin-1 converts the formation of the native matrilin-1 trimer into a mixture of trimer and dimer. Second, the vWF A domain protects matrilin-1 from proteolysis. We identified a latent proteolytic site next to the vWF A2 domain in matrilin-1, which is sensitive to the inhibitors of matrix proteases. Deletion of the abutting vWF A domain results in degradation of matrilin-1, presumably by exposing the adjacent proteolytic site. In addition, we also confirmed the vWF A domain is vital for the secretion of matrilin-3. Secretion of the mutant matrilin-3 harbouring a point mutation within the vWF A domain, as occurred in MED patients, is markedly reduced and delayed, resulting from intracellular retention of the mutant matrilin-3. Taken together, our data suggest that different mutations/deletions of the vWF A domain in matrilins may lead to distinct pathological mechanisms due to the multiple functions of the vWF A domain.

  17. Oligomeric rare-earth metal cluster complexes with endohedral transition metal atoms

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, Simon; Zimmermann, Sina; Brühmann, Matthias; Meyer, Eva; Rustige, Christian; Wolberg, Marike; Daub, Kathrin; Bell, Thomas; Meyer, Gerd, E-mail: gerd.meyer@uni-koeln.de

    2014-11-15

    Comproportionation reactions of rare-earth metal trihalides (RX{sub 3}) with the respective rare-earth metals (R) and transition metals (T) led to the formation of 22 oligomeric R cluster halides encapsulating T, in 19 cases for the first time. The structures of these compounds were determined by single-crystal X-ray diffraction and are composed of trimers ((T{sub 3}R{sub 11})X{sub 15}-type, P6{sub 3}/m), tetramers ((T{sub 4}R{sub 16})X{sub 28}(R{sub 4}) (P-43m), (T{sub 4}R{sub 16})X{sub 20} (P4{sub 2}/nnm), (T{sub 4}R{sub 16})X{sub 24}(RX{sub 3}){sub 4} (I4{sub 1}/a) and (T{sub 4}R{sub 16})X{sub 23} (C2/m) types of structure) and pentamers ((Ru{sub 5}La{sub 14}){sub 2}Br{sub 39}, Cc) of (TR{sub r}){sub n} (n=2–5) clusters. These oligomers are further enveloped by inner (X{sup i}) as well as outer (X{sup a}) halido ligands, which possess diverse functionalities and interconnect like oligomers through i–i, i–a and/or a–i bridges. The general features of the crystal structures for these new compounds are discussed and compared to literature entries as well as different structure types with oligomeric T centered R clusters. Dimers and tetramers originating from the aggregation of (TR{sub 6}) octahedra via common edges are more frequent than trimers and pentamers, in which the (TR{sub r}) clusters share common faces. - Graphical abstract: Rare earth-metal cluster complexes with endohedral transition metal atoms (TR{sub 6}) may connect via common edges or faces to form dimers, trimers, tetramers and pentamers of which the tetramers are the most prolific. Packing effects and electron counts play an important role. - Highlights: • Rare-earth metal cluster complexes encapsulate transition metal atoms. • Oligomers are built via connection of octahedral clusters via common edges or faces. • Dimers through pentamers with closed structures are known. • Tetramers including a tetrahedron of endohedral atoms are the most prolific.

  18. Characterization of oligomerization of a peptide from the ebola virus glycoprotein by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Egorov, V. V.; Gorshkov, A. N.; Murugova, T. N.; Vasin, A. V.; Lebedev, D. V.; Isaev-Ivanov, V. V.; Kiselev, O. I.

    2016-01-01

    Transmission electron microscopy (TEM) and small-angle neutron scattering (SANS) studies showed that model peptides QNALVCGLRQ (G33) and QNALVCGLRG (G31) corresponding to region 551–560 of the GP protein of the Sudan Ebola virus are prone to oligomerization in solution. Both peptides can form amyloid-like fibrills. The G33 peptide forms fibrils within one day of incubation, whereas the fibrillogenesis of the G31 peptide is observed only after incubation for several months. The possible role of the observed processes in the pathogenesis and the possibility of applying a combination of the TEM and SANS techniques to search for new compounds that are able to influence the protein oligomerization are discussed

  19. Characterization of oligomerization of a peptide from the ebola virus glycoprotein by small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Egorov, V. V., E-mail: vlaegur@omrb.pnpi.spb.ru [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation); Gorshkov, A. N. [Ministry of Health of the Russian Federation, Research Institute of Influenza (Russian Federation); Murugova, T. N. [Joint Institute for Nuclear Research (Russian Federation); Vasin, A. V. [Ministry of Health of the Russian Federation, Research Institute of Influenza (Russian Federation); Lebedev, D. V.; Isaev-Ivanov, V. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation); Kiselev, O. I. [Ministry of Health of the Russian Federation, Research Institute of Influenza (Russian Federation)

    2016-01-15

    Transmission electron microscopy (TEM) and small-angle neutron scattering (SANS) studies showed that model peptides QNALVCGLRQ (G33) and QNALVCGLRG (G31) corresponding to region 551–560 of the GP protein of the Sudan Ebola virus are prone to oligomerization in solution. Both peptides can form amyloid-like fibrills. The G33 peptide forms fibrils within one day of incubation, whereas the fibrillogenesis of the G31 peptide is observed only after incubation for several months. The possible role of the observed processes in the pathogenesis and the possibility of applying a combination of the TEM and SANS techniques to search for new compounds that are able to influence the protein oligomerization are discussed.

  20. Purification, crystallization and preliminary crystallographic analysis of Est-Y29: a novel oligomeric β-lactamase

    International Nuclear Information System (INIS)

    Kim, SeungBum; Joo, Sangbum; Yoon, Sangyoung; Kim, Sungsoo; Moon, Jongkook; Ryu, Yeonwoo; Kim, Kyeong Kyu; Kim, T. Doohun

    2009-01-01

    Est-Y29, a novel oligomeric class C β-lactamase from a metagenomic library, was crystallized in space group I4 1 and diffraction data were collected to 1.49 Å resolution. β-Lactam antibiotics such as penicillins and cephalosporins have a four-atom ring as a common element in their structure. The β-lactamases, which catalyze the inactivation of these antibiotics, are of great interest because of their high incidence in pathogenic bacteria. A novel oligomeric class C β-lactamase (Est-Y29) from a metagenomic library was expressed, purified and crystallized. The recombinant protein was expressed in Escherichia coli with an N-terminal 6×His tag and purified to homogeneity. EstY-29 was crystallized and X-ray intensity data were collected to 1.49 Å resolution using synchrotron radiation

  1. Characterization of oligomerization of a peptide from the ebola virus glycoprotein by small-angle neutron scattering

    Science.gov (United States)

    Egorov, V. V.; Gorshkov, A. N.; Murugova, T. N.; Vasin, A. V.; Lebedev, D. V.; Isaev-Ivanov, V. V.; Kiselev, O. I.

    2016-01-01

    Transmission electron microscopy (TEM) and small-angle neutron scattering (SANS) studies showed that model peptides QNALVCGLRQ (G33) and QNALVCGLRG (G31) corresponding to region 551-560 of the GP protein of the Sudan Ebola virus are prone to oligomerization in solution. Both peptides can form amyloid-like fibrills. The G33 peptide forms fibrils within one day of incubation, whereas the fibrillogenesis of the G31 peptide is observed only after incubation for several months. The possible role of the observed processes in the pathogenesis and the possibility of applying a combination of the TEM and SANS techniques to search for new compounds that are able to influence the protein oligomerization are discussed.

  2. Hitler's Death Camps.

    Science.gov (United States)

    Wieser, Paul

    1995-01-01

    Presents a high school lesson on Hitler's death camps and the widespread policy of brutality and oppression against European Jews. Includes student objectives, instructional procedures, and a chart listing the value of used clothing taken from the Jews. (CFR)

  3. Complications and Deaths - State

    Data.gov (United States)

    U.S. Department of Health & Human Services — Complications and deaths - state data. This data set includes state-level data for the hip/knee complication measure, the Agency for Healthcare Research and Quality...

  4. Eighth Amendment & Death Penalty.

    Science.gov (United States)

    Shortall, Joseph M.; Merrill, Denise W.

    1987-01-01

    Presents a lesson on capital punishment for juveniles based on three hypothetical cases. The goal of the lesson is to have students understand the complexities of decisions regarding the death penalty for juveniles. (JDH)

  5. Sudden Cardiac Death

    DEFF Research Database (Denmark)

    Risgaard, Bjarke; Winkel, Bo Gregers; Jabbari, Reza

    2017-01-01

    Objectives This study sought to describe the use of pharmacotherapy in a nationwide cohort of young patients with sudden cardiac death (SCD). Background Several drugs have been associated with an increased risk of SCD and sudden arrhythmic death syndrome (SADS). It remains unclear how...... pharmacotherapy may contribute to the overall burden of SCD in the general population. Methods This was a nationwide study that included all deaths that occurred between 2000 and 2009 and between 2007 and 2009 in people age 1 to 35 years and 36 to 49 years, respectively. Two physicians identified all SCDs through...... review of death certificates. Autopsy reports were collected. Pharmacotherapy prescribed within 90 days before SCD was identified in the Danish Registry of Medicinal Product Statistics. Results We identified 1,363 SCDs; median age was 38 years (interquartile range: 29 to 45 years), and 72% (n = 975) were men...

  6. Complications and Deaths - State

    Data.gov (United States)

    U.S. Department of Health & Human Services — Complications and deaths - state data. This data set includes state-level data for the hip/knee complication measure, the CMS Patient Safety Indicators, and 30-day...

  7. Orchestrating an Exceptional Death

    DEFF Research Database (Denmark)

    Jensen, Anja Marie Bornø

    processes of facing brain death and deciding about organ donation. This study suggests that organ donation should be understood as a ‘strange figure’ challenging traditions and attitudes regarding the boundaries between life and death and the practices surrounding dead human bodies. Simultaneously, organ...... donation can be comforting and furthermore enable some families to make sense of a sudden tragic death. Throughout the thesis, the concept of ‘orchestration’ serves as the overall theoretical framework to understand how families, hospital staff and, on a larger scale, Danish society attempt to perform......, reinterpret and translate death and organ donation into something culturally acceptable and sense making. With chapters focusing analytically on the performance of trust, the transformative practices of hope, the aesthetization of ambiguous bodies, the sociality of exchangeable organs and the organ donation...

  8. Existential concerns about death

    DEFF Research Database (Denmark)

    Moestrup, Lene

    2014-01-01

    Background Research suggests that addressing dying patients’ existential concerns can help improve their quality of life. Common existential conditions, such as a search for meaning and considerations about faith, are probably intensified in a palliative setting and existential concerns about death...... are likewise intensified when patients face their impending death. Knowledge of modern, secular existential concerns about death is under-researched, and therefore, it is difficult to develop and implement specifically targeted support to dying patients. Aim The aim of this paper is to present the results from...... a qualitative field study illuminating the variety of dying patients´ existential concerns about their impending death. Method Data was generated through ethnographic fieldwork comprising 17 semi-structured interviews with dying patients and 38 days of participant observation at three Danish hospices. Results...

  9. Life not death

    DEFF Research Database (Denmark)

    Milner, George R.; Boldsen, Jesper L.

    2017-01-01

    Analytically sophisticated paleoepidemiology is a relatively new development in the characterization of past life experiences. It is based on sound paleopathological observations, accurate age-at-death estimates, an explicit engagement with the nature of mortality samples, and analytical procedures...

  10. Complications and Deaths - Hospital

    Data.gov (United States)

    U.S. Department of Health & Human Services — Complications and deaths - provider data. This data set includes provider data for the hip/knee complication measure, CMS Patient Safety Indicators of serious...

  11. Complications and Deaths - National

    Data.gov (United States)

    U.S. Department of Health & Human Services — Complications and deaths - national data. This data set includes national-level data for the hip/knee complication measure, the CMS Patient Safety Indicators, and...

  12. Development, validation and evaluation of an analytical method for the determination of monomeric and oligomeric procyanidins in apple extracts.

    Science.gov (United States)

    Hollands, Wendy J; Voorspoels, Stefan; Jacobs, Griet; Aaby, Kjersti; Meisland, Ane; Garcia-Villalba, Rocio; Tomas-Barberan, Francisco; Piskula, Mariusz K; Mawson, Deborah; Vovk, Irena; Needs, Paul W; Kroon, Paul A

    2017-04-28

    There is a lack of data for individual oligomeric procyanidins in apples and apple extracts. Our aim was to develop, validate and evaluate an analytical method for the separation, identification and quantification of monomeric and oligomeric flavanols in apple extracts. To achieve this, we prepared two types of flavanol extracts from freeze-dried apples; one was an epicatechin-rich extract containing ∼30% (w/w) monomeric (-)-epicatechin which also contained oligomeric procyanidins (Extract A), the second was an oligomeric procyanidin-rich extract depleted of epicatechin (Extract B). The parameters considered for method optimisation were HPLC columns and conditions, sample heating, mass of extract and dilution volumes. The performance characteristics considered for method validation included standard linearity, method sensitivity, precision and trueness. Eight laboratories participated in the method evaluation. Chromatographic separation of the analytes was best achieved utilizing a Hilic column with a binary mobile phase consisting of acidic acetonitrile and acidic aqueous methanol. The final method showed linearity for epicatechin in the range 5-100μg/mL with a correlation co-efficient >0.999. Intra-day and inter-day precision of the analytes ranged from 2 to 6% and 2 to 13% respectively. Up to dp3, trueness of the method was >95% but decreased with increasing dp. Within laboratory precision showed RSD values <5 and 10% for monomers and oligomers, respectively. Between laboratory precision was 4 and 15% (Extract A) and 7 and 30% (Extract B) for monomers and oligomers, respectively. An analytical method for the separation, identification and quantification of procyanidins in an apple extract was developed, validated and assessed. The results of the inter-laboratory evaluation indicate that the method is reliable and reproducible. Copyright © 2017. Published by Elsevier B.V.

  13. Both Ca2+ and Zn2+ are essential for S100A12 protein oligomerization and function

    Directory of Open Access Journals (Sweden)

    Shekhtman Alexander

    2009-04-01

    Full Text Available Abstract Background Human S100A12 is a member of the S100 family of EF-hand calcium-modulated proteins that are associated with many diseases including cancer, chronic inflammation and neurological disorders. S100A12 is an important factor in host/parasite defenses and in the inflammatory response. Like several other S100 proteins, it binds zinc and copper in addition to calcium. Mechanisms of zinc regulation have been proposed for a number of S100 proteins e.g. S100B, S100A2, S100A7, S100A8/9. The interaction of S100 proteins with their targets is strongly dependent on cellular microenvironment. Results The aim of the study was to explore the factors that influence S100A12 oligomerization and target interaction. A comprehensive series of biochemical and biophysical experiments indicated that changes in the concentration of calcium and zinc led to changes in the oligomeric state of S100A12. Surface plasmon resonance confirmed that the presence of both calcium and zinc is essential for the interaction of S100A12 with one of its extracellular targets, RAGE – the Receptor for Advanced Glycation End products. By using a single-molecule approach we have shown that the presence of zinc in tissue culture medium favors both the oligomerization of exogenous S100A12 protein and its interaction with targets on the cell surface. Conclusion We have shown that oligomerization and target recognition by S100A12 is regulated by both zinc and calcium. Our present work highlighted the potential role of calcium-binding S100 proteins in zinc metabolism and, in particular, the role of S100A12 in the cross talk between zinc and calcium in cell signaling.

  14. Synthesis and characterization of an octaimidazolium-based polyhedral oligomeric silsesquioxanes ionic liquid by an ion-exchange reaction.

    Science.gov (United States)

    Tan, Jinglin; Ma, Depeng; Sun, Xingrong; Feng, Shengyu; Zhang, Changqiao

    2013-04-07

    Preparation of POSS-min-DS, an octaimidazolium-based polyhedral oligomeric silsesquioxanes (POSS) room temperature ionic liquid, by an ion-exchange reaction between POSS and sodium dodecyl sulfate was reported. Octaimidazolium-based POSS was synthesized with more than 98% yield within 3 h. POSS-min-DS and octaimidazolium-based POSS were confirmed by (1)H, (13)C, and (29)Si NMR, FT-IR and elemental analysis.

  15. Live-cell visualization of gasdermin D-driven pyroptotic cell death.

    Science.gov (United States)

    Rathkey, Joseph K; Benson, Bryan L; Chirieleison, Steven M; Yang, Jie; Xiao, Tsan S; Dubyak, George R; Huang, Alex Y; Abbott, Derek W

    2017-09-01

    Pyroptosis is a form of cell death important in defenses against pathogens that can also result in a potent and sometimes pathological inflammatory response. During pyroptosis, GSDMD (gasdermin D), the pore-forming effector protein, is cleaved, forms oligomers, and inserts into the membranes of the cell, resulting in rapid cell death. However, the potent cell death induction caused by GSDMD has complicated our ability to understand the biology of this protein. Studies aimed at visualizing GSDMD have relied on expression of GSDMD fragments in epithelial cell lines that naturally lack GSDMD expression and also lack the proteases necessary to cleave GSDMD. In this work, we performed mutagenesis and molecular modeling to strategically place tags and fluorescent proteins within GSDMD that support native pyroptosis and facilitate live-cell imaging of pyroptotic cell death. Here, we demonstrate that these fusion proteins are cleaved by caspases-1 and -11 at Asp-276. Mutations that disrupted the predicted p30-p20 autoinhibitory interface resulted in GSDMD aggregation, supporting the oligomerizing activity of these mutations. Furthermore, we show that these novel GSDMD fusions execute inflammasome-dependent pyroptotic cell death in response to multiple stimuli and allow for visualization of the morphological changes associated with pyroptotic cell death in real time. This work therefore provides new tools that not only expand the molecular understanding of pyroptosis but also enable its direct visualization. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Oligomeric adiponectin forms and their complexes in the blood of healthy donors and patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Kogan, Alexander E; Filatov, Vladimir L; Kolosova, Olga V; Katrukha, Ivan A; Mironova, Ekaterina V; Zhuravleva, Natalya S; Nagibin, Oleg A; Kara, Andrei N; Bereznikova, Anastasiya V; Katrukha, Alexey G

    2013-01-01

    Adiponectin (Adn) is a protein that circulates in the blood in several oligomeric forms, namely low-, medium-, and high-molecular-weight forms. Adn may serve as a risk factor for type 2 diabetes mellitus (T2DM). The aims of this work were (1) to produce monoclonal antibodies (MAbs) specific to different Adn oligomeric forms, (2) to design immunoassays suitable for measuring the Adn forms present in human blood, and (3) to investigate the changes in Adn forms that occur in patients with T2DM. Gel filtration, fluoroimmunoassays, and Western blotting were utilized as major techniques in this study. MAbs recognizing various oligomeric forms of Adn were obtained. Complexes between Adn and complement component C1q and between the low molecular weight form of Adn and albumin were described in human blood. A decrease in the total Adn and Adn-albumin complex levels in the blood of patients with T2DM and no difference in the levels of the Adn-C1q complex in comparison with healthy volunteers were demonstrated. An Adn94-Adn63 fluoroimmunoassay was selected as the technique that most accurately measured the mass ratio of Adn oligomers in blood samples, and an Adn214-Adn27 assay that measured the low-molecular-weight form of Adn only.

  17. Detection of Amyloid Beta (Aβ) Oligomeric Composition Using Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI MS)

    Science.gov (United States)

    Wang, Jasmine S.-H.; Whitehead, Shawn N.; Yeung, Ken K.-C.

    2018-02-01

    The use of MALDI MS as a fast and direct method to detect the Aβ oligomers of different masses is examined in this paper. Experimental results suggest that Aβ oligomers are ionized and detected as singly charged ions, and thus, the resulting mass spectrum directly reports the oligomer size distribution. Validation experiments were performed to verify the MS data against artifacts. Mass spectra collected from modified Aβ peptides with different propensities for aggregation were compared. Generally, the relative intensities of multimers were higher from samples where oligomerization was expected to be more favorable, and vice versa. MALDI MS was also able to detect the differences in oligomeric composition before and after the incubation/oligomerization step. Such differences in sample composition were also independently confirmed with an in vitro Aβ toxicity study on primary rat cortical neurons. An additional validation was accomplished through removal of oligomers from the sample using molecular weight cutoff filters; the resulting MS data correctly reflected the removal at the expected cutoff points. The results collectively validated the ability of MALDI MS to assess the monomeric/multimeric composition of Aβ samples. [Figure not available: see fulltext.

  18. Spa47 is an oligomerization-activated type three secretion system (T3SS) ATPase from Shigella flexneri.

    Science.gov (United States)

    Burgess, Jamie L; Jones, Heather B; Kumar, Prashant; Toth, Ronald T; Middaugh, C Russell; Antony, Edwin; Dickenson, Nicholas E

    2016-05-01

    Gram-negative pathogens often use conserved type three secretion systems (T3SS) for virulence. The Shigella type three secretion apparatus (T3SA) penetrates the host cell membrane and provides a unidirectional conduit for injection of effectors into host cells. The protein Spa47 localizes to the base of the apparatus and is speculated to be an ATPase that provides the energy for T3SA formation and secretion. Here, we developed an expression and purification protocol, producing active Spa47 and providing the first direct evidence that Spa47 is a bona fide ATPase. Additionally, size exclusion chromatography and analytical ultracentrifugation identified multiple oligomeric species of Spa47 with the largest greater than 8 fold more active for ATP hydrolysis than the monomer. An ATPase inactive Spa47 point mutant was then engineered by targeting a conserved Lysine within the predicted Walker A motif of Spa47. Interestingly, the mutant maintained a similar oligomerization pattern as active Spa47, but was unable to restore invasion phenotype when used to complement a spa47 null S. flexneri strain. Together, these results identify Spa47 as a Shigella T3SS ATPase and suggest that its activity is linked to oligomerization, perhaps as a regulatory mechanism as seen in some related pathogens. Additionally, Spa47 catalyzed ATP hydrolysis appears to be essential for host cell invasion, providing a strong platform for additional studies dissecting its role in virulence and providing an attractive target for anti-infective agents. © 2016 The Protein Society.

  19. Coatings of molecularly imprinted polymers based on polyhedral oligomeric silsesquioxane for open tubular capillary electrochromatography.

    Science.gov (United States)

    Zhao, Qing-Li; Zhou, Jin; Zhang, Li-Shun; Huang, Yan-Ping; Liu, Zhao-Sheng

    2016-05-15

    Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic coating for capillary electrochromatography. The imprinted monolithic coating was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), S-amlodipine (template), methacrylic acid (functional monomer), and 2-methacrylamidopropyl methacrylate (crosslinker), in a porogenic mixture of toluene-isooctane. The influence of synthesis parameters on the imprinting effect and separation performance, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest resolution for enantiomers separation on the imprinted monolithic column prepared with MA 0702 was up to 22.3, about 2 times higher than that prepared in absence of the POSS. Column efficiency on the POSS-based MIP coatings was beyond 30,000 plate m(-1). The comparisons between MIP coating synthesized with the POSS and without the POSS were made in terms of selectivity, column efficiency, and resolution. POSS-based MIP capillaries with naproxen or zopiclone was also prepared and separation of enantiomers can be achieved. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Dielectric properties of polyhedral oligomeric silsesquioxane (POSS)-based nanocomposites at 77k

    International Nuclear Information System (INIS)

    Pan, Ming-Jen; Gorzkowski, Edward; McAllister, Kelly

    2011-01-01

    The goal of this study is to develop dielectric nanocomposites for high energy density applications at liquid nitrogen temperature by utilizing a unique nano-material polyhedral oligomeric silsesquioxanes (POSS). A POSS molecule is consisted of a silica cage core with 8 silicon and 12 oxygen atoms and organic functional groups attached to the corners of the cage. In this study, we utilize POSS for the fabrication of nanocomposites both as a silica nanoparticle filler to enhance the breakdown strength and as a surfactant for effective dispersion of high permittivity ceramic nanoparticles in a polymer matrix. The matrix materials selected for the study are polyvinylidene fluoride (PVDF) and poly(methyl methacrylate) (PMMA). The ceramic nanoparticles are barium strontium titanate (BST 50/50) and strontium titanate. The dielectric properties of the solution-cast nanocomposites films were correlated to the composition and processing conditions. We determined that the addition of POSS did not provide enhanced dielectric performance in PVDF- and PMMA-based materials at either room temperature or 77K. In addition, we found that the dielectric breakdown strength of PMMA is lower at 77K than at room temperature, contradicting literature data.

  1. Ion Channel Conformation and Oligomerization Assessment by Site-Directed Spin Labeling and Pulsed-EPR.

    Science.gov (United States)

    Pliotas, Christos

    2017-01-01

    Mechanosensitive (MS) ion channels are multimeric integral membrane proteins that respond to increased lipid bilayer tension by opening their nonselective pores to release solutes and relieve increased cytoplasmic pressure. These systems undergo major conformational changes during gating and the elucidation of their mechanism requires a deep understanding of the interplay between lipids and proteins. Lipids are responsible for transmitting lateral tension to MS channels and therefore play a key role in obtaining a molecular-detail model for mechanosensation. Site-directed spin labeling combined with electron paramagnetic resonance (EPR) spectroscopy is a powerful spectroscopic tool in the study of proteins. The main bottleneck for its use relates to challenges associated with successful isolation of the protein of interest, introduction of paramagnetic labels on desired sites, and access to specialized instrumentation and expertise. The design of sophisticated experiments, which combine a variety of existing EPR methodologies to address a diversity of specific questions, require knowledge of the limitations and strengths, characteristic of each particular EPR method. This chapter is using the MS ion channels as paradigms and focuses on the application of different EPR techniques to ion channels, in order to investigate oligomerization, conformation, and the effect of lipids on their regulation. The methodology we followed, from the initial strategic selection of mutants and sample preparation, including protein purification, spin labeling, reconstitution into lipid mimics to the complete set-up of the pulsed-EPR experiments, is described in detail. © 2017 Elsevier Inc. All rights reserved.

  2. Structure-properties relationships of polyhedral oligomeric silsesquioxane (POSS filled PS nanocomposites

    Directory of Open Access Journals (Sweden)

    J. J. Schwab

    2012-07-01

    Full Text Available The polyhedral oligomeric silsesquioxane (POSS additivated polystyrene (PS based nanocomposites were prepared by melt processing and the structure-properties relationships of the POSS-PS systems were compared to those of the neat PS. In order to investigate the effect of these structural parameters on the final properties of the polymer nanocomposites, five different kinds of POSS samples were used, in particular, POSS with different inorganic cage and with different organic pendent groups. The rheological investigation suggests clearly that the POSS acts as a plasticizer and that the processability of the PS was positively modified. The affinity between the POSS samples and the PS matrix was estimated by the calculated theoretical solubility parameters, considering the Hoy’s method and by morphology analysis. Minor difference between the solubility parameter of POSS and the matrix means better compatibility and no aggregation tendency. Furthermore, the POSS loading leads to a decrease of the rigidity, of the glass transition temperature and of the damping factor of the nanocomposite systems. The loading of different POSS molecules with open cage leads to a more pronounced effect on all the investigated properties that the loading of the POSS molecules with closed cage. Moreover, the melt properties are significantly influenced by the type of inorganic framework, by the type of the pendent organic groups and by the interaction between the POSS organic groups and the host matrix, while, the solid state properties appears to be influenced more by the kind of cage.

  3. Cyclic GMP-AMP synthase is activated by double-stranded DNA-induced oligomerization.

    Science.gov (United States)

    Li, Xin; Shu, Chang; Yi, Guanghui; Chaton, Catherine T; Shelton, Catherine L; Diao, Jiasheng; Zuo, Xiaobing; Kao, C Cheng; Herr, Andrew B; Li, Pingwei

    2013-12-12

    Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor mediating innate antimicrobial immunity. It catalyzes the synthesis of a noncanonical cyclic dinucleotide, 2',5' cGAMP, that binds to STING and mediates the activation of TBK1 and IRF-3. Activated IRF-3 translocates to the nucleus and initiates the transcription of the IFN-β gene. The structure of mouse cGAS bound to an 18 bp dsDNA revealed that cGAS interacts with dsDNA through two binding sites, forming a 2:2 complex. Enzyme assays and IFN-β reporter assays of cGAS mutants demonstrated that interactions at both DNA binding sites are essential for cGAS activation. Mutagenesis and DNA binding studies showed that the two sites bind dsDNA cooperatively and that site B plays a critical role in DNA binding. The structure of mouse cGAS bound to dsDNA and 2',5' cGAMP provided insight into the catalytic mechanism of cGAS. These results demonstrated that cGAS is activated by dsDNA-induced oligomerization. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Photo-polymerization of photocurable resins containing polyhedral oligomeric silsesquioxane methacrylate

    International Nuclear Information System (INIS)

    Lin, Ho-May; Wu, Shi-Yin; Chang, Feng-Chih; Yen, Ying-Chieh

    2011-01-01

    Photocurable resins, bisphenol A propoxylate glycerolate diacrylate (BPA-PGDA, containing two hydroxyl) and bisphenol A propoxylate diacrylate (BPA-PDA), with fixed photoinitiator (Irgacure 907) concentration and various contents of methacrylisobutyl polyhedral oligomeric silsesquioxane (MI-POSS) were prepared and characterized by FTIR spectroscopy, scanning electron microscope and differential photocalorimetry. The MI-POSS molecules form crystals or aggregated particles in the cured resin matrix. The BPA-PGDA series photocurable resins show higher viscosity and lower photo-polymerization reactivity than the BPA-PDA series resins. The photo-polymerization rate and conversion of BPA-PGDA series are improved with increasing MI-POSS content. On the contrary, the photo-polymerization behavior of BPA-PDA series photocurable resins remains nearly unchanged by the addition of MI-POSS. Hydrogen-bonding interaction between the hydroxyl of BPA-PGDA and the siloxane of MI-POSS tends to attract and concentrate these acrylate double bonds around MI-POSS particles and thus enhances the photo-polymerization rate and conversion.

  5. Hydroxychloroquine induces inhibition of collagen type II and oligomeric matrix protein COMP expression in chondrocytes

    Directory of Open Access Journals (Sweden)

    Tao Li

    2016-06-01

    Full Text Available The aim of this study was to investigate the effect of hydroxychloroquine on the level of collagen type II and oligomeric matrix protein COMP expression in chondrocytes of knee osteoarthritis. The rate of growth in cartilage cells was analyzed using MTT assay whereas the Col-2 and COMP expression levels were detected by RT-PCR and Western blotting analyses. For the determination of MMP-13 expression, ELISA test was used. The results revealed no significant change in the rate of cartilage cell proliferation in hydroxychloroquine-treated compared to untreated cells. Hydroxychloro-quine treatment exhibited concentration- and time-dependent effect on the inhibition of collagen type II and COMP expression in chondrocytes. However, its treatment caused a significant enhancement in the expression levels of MMP-13 compared to the untreated cells. Therefore, hydroxychloro-quine promotes expression of MMP-13 and reduces collagen type II and COMP expression levels in chondrocytes without any significant change in the growth of cells.

  6. Hexokinase 2 from Saccharomyces cerevisiae: regulation of oligomeric structure by in vivo phosphorylation at serine-14.

    Science.gov (United States)

    Behlke, J; Heidrich, K; Naumann, M; Müller, E C; Otto, A; Reuter, R; Kriegel, T

    1998-08-25

    Homodimeric hexokinase 2 from Saccharomyces cerevisiae is known to have two sites of phosphorylation: for serine-14 the modification in vivo increases with glucose exhaustion [Kriegel et al. (1994) Biochemistry 33, 148-152], while for serine-157 it occurs in vitro with ATP in the presence of nonphosphorylateable five-carbon analogues of glucose [Heidrich et al. (1997) Biochemistry 36, 1960-1964]. We show now by site-directed mutagenesis and sedimentation analysis that serine-14 phosphorylation affects the oligomeric state of hexokinase, its substitution by glutamate causing complete dissociation; glutamate exchange for serine-157 does not. Phosphorylation of wild-type hexokinase at serine-14 likewise causes dissociation in vitro. In view of the higher glucose affinity of monomeric hexokinase and the high hexokinase concentration in yeast [Womack, F., and Colowick, S. P. (1978) Arch. Biochem. Biophys. 191, 742-747; Mayes, E. L., Hoggett, J. G., and Kellett, G. L. (1983) Eur. J. Biochem. 133, 127-134], we speculate that the in vivo phosphorylation at serine-14 as transiently occurring in glucose derepression might provide a mechanism to improve glucose utilization from low level and/or that nuclear localization of the monomer might be involved in the signal transduction whereby glucose causes catabolite repression.

  7. Formation of semisolid, oligomerized aqueous SOA: lab simulations of cloud processing.

    Science.gov (United States)

    Hawkins, Lelia N; Baril, Molly J; Sedehi, Nahzaneen; Galloway, Melissa M; De Haan, David O; Schill, Gregory P; Tolbert, Margaret A

    2014-02-18

    Glyoxal, methylglyoxal, glycolaldehyde, and hydroxyacetone form N-containing and oligomeric compounds during simulated cloud processing with small amines. Using a novel hygroscopicity tandem differential mobility analysis (HTDMA) system that allows varied humidification times, the hygroscopic growth (HG) of each of the resulting products of simulated cloud processing was measured. Continuous water uptake (gradual deliquescence) was observed beginning at ∼ 40% RH for all aldehyde-methylamine products. Particles containing ionic reaction products of either glyoxal or glycine were most hygroscopic, with HG between 1.16 and 1.20 at 80% RH. Longer humidification times (up to 20 min) produced an increase in growth factors for glyoxal-methylamine (19% by vol) and methylglyoxal-methylamine (8% by vol) aerosol, indicating that unusually long equilibration times can be required for HTDMA measurements of such particles. Glyoxal- and methylglyoxal-methylamine aerosol particles shattered in Raman microscopy impact-flow experiments, revealing that the particles were semisolid. Similar experiments on glycolaldehyde- and hydroxyacetone-methylamine aerosol found that the aerosol particles were liquid when dried for glyoxal > glycolaldehyde = hydroxyacetone, likely caused by the speed of oligomer formation in each system.

  8. Transparent cellulose/polyhedral oligomeric silsesquioxane nanocomposites with enhanced UV-shielding properties.

    Science.gov (United States)

    Feng, Ye; Zhang, Jinming; He, Jiasong; Zhang, Jun

    2016-08-20

    The solubility of eight types of polyhedral oligomeric silsesquioxane (POSS) derivatives in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) and the dispersion of POSS in cellulose matrix were examined. Only a special POSS containing both aminophenyl and nitrophenyl groups (POSS-AN, NH2:NO2=2:6) was selected to prepare nanocomposites, because of its good solubility in AmimCl and high stability during the preparation process. POSS-AN nanoparticles were uniformly dispersed in a cellulose matrix with a size of 30-40nm, and so the resultant cellulose/POSS-AN nanocomposite films were transparent. The mechanical properties of the films achieved a maximum tensile strength of 190MPa after addition of 2wt% POSS-AN. Interestingly, all of the cellulose/POSS-AN films exhibited high UV-absorbing capability. For the 15wt% cellulose/POSS-AN film, the transmittance of UVA (315-400nm) and UVB (280-315nm) was only 9.1% and nearly 0, respectively. The UV aging and shielding experiments showed that the transparent cellulose/POSS-AN nanocomposite films possessed anti-UV aging and UV shielding properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Construction of porous cationic frameworks by crosslinking polyhedral oligomeric silsesquioxane units with N-heterocyclic linkers

    Science.gov (United States)

    Chen, Guojian; Zhou, Yu; Wang, Xiaochen; Li, Jing; Xue, Shuang; Liu, Yangqing; Wang, Qian; Wang, Jun

    2015-06-01

    In fields of materials science and chemistry, ionic-type porous materials attract increasing attention due to significant ion-exchanging capacity for accessing diversified applications. Facing the fact that porous cationic materials with robust and stable frameworks are very rare, novel tactics that can create new type members are highly desired. Here we report the first family of polyhedral oligomeric silsesquioxane (POSS) based porous cationic frameworks (PCIF-n) with enriched poly(ionic liquid)-like cationic structures, tunable mesoporosities, high surface areas (up to 1,025 m2 g-1) and large pore volumes (up to 0.90 cm3 g-1). Our strategy is designing the new rigid POSS unit of octakis(chloromethyl)silsesquioxane and reacting it with the rigid N-heterocyclic cross-linkers (typically 4,4‧-bipyridine) for preparing the desired porous cationic frameworks. The PCIF-n materials possess large surface area, hydrophobic and special anion-exchanging property, and thus are used as the supports for loading guest species PMo10V2O405- the resultant hybrid behaves as an efficient heterogeneous catalyst for aerobic oxidation of benzene and H2O2-mediated oxidation of cyclohexane.

  10. IntraGolgi distribution of the Conserved Oligomeric Golgi (COG) complex

    International Nuclear Information System (INIS)

    Vasile, Eliza; Oka, Toshihiko; Ericsson, Maria; Nakamura, Nobuhiro; Krieger, Monty

    2006-01-01

    The Conserved Oligomeric Golgi (COG) complex is an eight-subunit (Cog1-8) peripheral Golgi protein involved in membrane trafficking and glycoconjugate synthesis. COG appears to participate in retrograde vesicular transport and is required to maintain normal Golgi structure and function. COG mutations interfere with normal transport, distribution, and/or stability of Golgi proteins associated with glycoconjugate synthesis and trafficking, and lead to failure of spermatogenesis in Drosophila melanogaster, misdirected migration of gonadal distal tip cells in Caenorhabditis elegans, and type II congenital disorders of glycosylation in humans. The mechanism by which COG influences Golgi structure and function is unclear. Immunogold electron microscopy was used to visualize the intraGolgi distribution of a functional, hemagglutinin epitope-labeled COG subunit, Cog1-HA, that complements the Cog1-deficiency in Cog1-null Chinese hamster ovary cells. COG was found to be localized primarily on or in close proximity to the tips and rims of the Golgi's cisternae and their associated vesicles and on vesicles and vesiculo-tubular structures seen on both the cis and trans-Golgi Network faces of the cisternal stacks, in some cases on COPI containing vesicles. These findings support the proposal that COG is directly involved in controlling vesicular retrograde transport of Golgi resident proteins throughout the Golgi apparatus

  11. Polyhedral oligomeric silsesquioxane (POSS)–poly(ethylene glycol) (PEG) hybrids as injectable biomaterials

    International Nuclear Information System (INIS)

    Engstrand, Johanna; López, Alejandro; Engqvist, Håkan; Persson, Cecilia

    2012-01-01

    One of the major issues with the currently available injectable biomaterials for hard tissue replacement is the mismatch between their mechanical properties and those of the surrounding bone. Hybrid bone cements that combine the benefits of tough polymeric and bioactive ceramic materials could become a good alternative. In this work, polyhedral oligomeric silsesquioxane (POSS) was copolymerized with poly(ethylene glycol) (PEG) to form injectable in situ cross-linkable hybrid cements. The hybrids were characterized in terms of their mechanical, rheological, handling and in vitro bioactive properties. The results indicated that hybridization improves the mechanical and bioactive properties of POSS and PEG. The Young moduli of the hybrids were lower than those of commercial cements and more similar to those of cancellous bone. Furthermore, the strength of the hybrids was similar to that of commercial cements. Calcium deficient hydroxyapatite grew on the surface of the hybrids after 28 days in PBS, indicating bioactivity. The study showed that PEG–POSS-based hybrid materials are a promising alternative to commercial bone cements. (paper)

  12. Optimization of oligomeric enzyme activity in ionic liquids using Rhodotorula glutinis yeast phenylalanine ammonia lyase.

    Science.gov (United States)

    Barron, Christiaan C; Sponagle, Brandon J D; Arivalagan, Pugazhendhi; D'Cunha, Godwin B

    2017-01-01

    Phenylalanine ammonia lyase (E.C.4.3.1.24, PAL) activity of Rhodotorula glutinis yeast has been demonstrated in four commonly used ionic liquids. PAL forward reaction was carried out in 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][MeSO 4 ]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]) and 1-butyl-3-methylimidazolium lactate ([BMIM][lactate]). Our experiments have revealed that PAL is catalytically active in ionic liquids and the enzyme activity in ([BMIM][PF 6 ]) is comparable to that obtained in aqueous buffer medium. Different conditions were optimized for maximal PAL forward activity including time of incubation (30.0min) L -phenylalanine substrate concentration (30.0mM), nature of buffer (50.0mM Tris-HCl), pH (9.0), temperature (37°C), and speed of agitation (100 rev min -1 ). Under these optimized conditions, about 83% conversion of substrate to product was obtained for the PAL forward reaction that was determined using UV spectroscopy at 290nm. PAL reverse reaction in ([BMIM][PF 6 ]) was determined spectrophotometrically at 520nm; and about 59% substrate conversion was obtained. This data provides further knowledge in enzyme biocatalysis in non-aqueous media, and may be of importance when studying the function of other oligomeric/multimeric proteins and enzymes in ionic liquids. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Bimolecular Fluorescence Complementation of Alpha-synuclein Demonstrates its Oligomerization with Dopaminergic Phenotype in Mice

    Directory of Open Access Journals (Sweden)

    Waijiao Cai

    2018-03-01

    Full Text Available Alpha-synuclein (αSyn is encoded by the first causal gene identified in Parkinson's disease (PD and is the main component of Lewy bodies, a pathological hallmark of PD. aSyn-based animal models have contributed to our understanding of PD pathophysiology and to the development of therapeutics. Overexpression of human wildtype αSyn by viral vectors in rodents recapitulates the loss of dopaminergic neurons from the substantia nigra, another defining pathological feature of the disease. The development of a rat model exhibiting bimolecular fluorescence complementation (BiFC of αSyn by recombinant adeno-associated virus facilitates detection of the toxic αSyn oligomers species. We report here neurochemical, neuropathological and behavioral characterization of BiFC of αSyn in mice. Overexpression and oligomerization of αSyn through BiFC is detected by conjugated fluorescence. Reduced striatal dopamine and loss of nigral dopaminergic neurons are accompanied neuroinflammation and abnormal motor activities. Our mouse model may provide a valuable tool to study the role of αSyn in PD and to explore therapeutic approaches. Keywords: Parkinson's disease, Alpha-synuclein, Mouse model, Oligomers, Neuroinflammation

  14. In-situ photocrosslinkable nanohybrid elastomer based on polybutadiene/polyhedral oligomeric silsesquioxane

    Energy Technology Data Exchange (ETDEWEB)

    Mirmohammadi, Seyed Amin, E-mail: mirmohammadi.sa@gmail.com [Department of Polymerization Engineering, Iran Polymer and Petrochemical Institute (IPPI), P. O. Box: 14965/115, Tehran (Iran, Islamic Republic of); Nekoomanesh-Haghighi, Mehdi, E-mail: m.nekoomanesh@ippi.ac.ir [Department of Polymerization Engineering, Iran Polymer and Petrochemical Institute (IPPI), P. O. Box: 14965/115, Tehran (Iran, Islamic Republic of); Mohammadian Gezaz, Somayyeh [Department of Chemical Engineering, Payame Noor University (PNU), P. O. Box: 19395-3697, Tehran (Iran, Islamic Republic of); Bahri-Laleh, Naeimeh [Department of Polymerization Engineering, Iran Polymer and Petrochemical Institute (IPPI), P. O. Box: 14965/115, Tehran (Iran, Islamic Republic of); Atai, Mohammad [Department of Polymer Science, Iran Polymer and Petrochemical Institute (IPPI), P. O. Box: 14965/115, Tehran (Iran, Islamic Republic of)

    2016-11-01

    Hydroxyl functionalized nano-sized POSS or ethyleneglycol as diol monomers was incorporated to hydroxyl-terminated polybutadiene (HTPBD) chain in the presence of fumaryl chloride as extender. Blue light photocrosslinking system based on camphorquinone (photoinitiator) and dimethylaminoethyl methacrylate (accelerator) was applied to cure these two synthesized fumarate based macromers. Self-crosslinkability of unsaturated macromers and also crosslinking in presence of a reactive diluent were investigated in absence and presence of 1,4-butanediol dimethacrylate, respectively. Finally, photocured samples were characterized by XRD, SEM, equilibrium swelling study, TGA, DMTA, AFM and cell culture. The results showed that incorporation of POSS nanoparticle into the polymer matrix with a perfect distribution and dispersion can enhance thermal stability, mechanical and biocompatibility properties which can prove a good potential of this in-situ photocrosslinkable nanohybrid in medical applications. - Highlights: • Polyhedral oligomeric silsesquioxane was incorporated to HTPBD by fumaryl chloride as extender. • A reactive diluent was used to improve photocrosslinking process of the unsaturated nanohybrid elastomers. • Nanohybrids showed enhanced properties such as thermal stability, mechanical and biocompatibility. • Improved properties were obtained for photocured samples in presence of reactive diluent.

  15. Sedimentation Velocity Analysis of Large Oligomeric Chromatin Complexes Using Interference Detection.

    Science.gov (United States)

    Rogge, Ryan A; Hansen, Jeffrey C

    2015-01-01

    Sedimentation velocity experiments measure the transport of molecules in solution under centrifugal force. Here, we describe a method for monitoring the sedimentation of very large biological molecular assemblies using the interference optical systems of the analytical ultracentrifuge. The mass, partial-specific volume, and shape of macromolecules in solution affect their sedimentation rates as reflected in the sedimentation coefficient. The sedimentation coefficient is obtained by measuring the solute concentration as a function of radial distance during centrifugation. Monitoring the concentration can be accomplished using interference optics, absorbance optics, or the fluorescence detection system, each with inherent advantages. The interference optical system captures data much faster than these other optical systems, allowing for sedimentation velocity analysis of extremely large macromolecular complexes that sediment rapidly at very low rotor speeds. Supramolecular oligomeric complexes produced by self-association of 12-mer chromatin fibers are used to illustrate the advantages of the interference optics. Using interference optics, we show that chromatin fibers self-associate at physiological divalent salt concentrations to form structures that sediment between 10,000 and 350,000S. The method for characterizing chromatin oligomers described in this chapter will be generally useful for characterization of any biological structures that are too large to be studied by the absorbance optical system. © 2015 Elsevier Inc. All rights reserved.

  16. Role of redox environment on the oligomerization of higher molecular weight adiponectin

    Directory of Open Access Journals (Sweden)

    Nuñez Martha

    2011-05-01

    Full Text Available Abstract Background Adiponectin is an adipocyte-secreted hormone with insulin-sensitizing and anti-inflammatory actions. The assembly of trimeric, hexameric, and higher molecular weight (HMW species of adiponectin is a topic of significant interest because physiological actions of adiponectin are oligomer-specific. In addition, adiponectin assembly is an example of oxidative oligomerization of multi-subunit protein complexes in endoplasmic reticulum (ER. Results We previously reported that trimers assemble into HMW adiponectin via intermediates stabilized by disulfide bonds, and complete oxidation of available cysteines locks adiponectin in hexameric conformation. In this study, we examined the effects of redox environment on the rate of oligomer formation and the distribution of oligomers. Reassembly of adiponectin under oxidizing conditions accelerated disulfide bonding but favored formation of hexamers over the HMW species. Increased ratios of HMW to hexameric adiponectin could be achieved rapidly under oxidizing conditions by promoting disulfide rearrangement. Conclusions Based upon these observations, we propose oxidative assembly of multi-subunit adiponectin complexes in a defined and stable redox environment is favored under oxidizing conditions coupled with high rates of disulfide rearrangement.

  17. Reversible unfolding of infectious prion assemblies reveals the existence of an oligomeric elementary brick.

    Directory of Open Access Journals (Sweden)

    Angélique Igel-Egalon

    2017-09-01

    Full Text Available Mammalian prions, the pathogens that cause transmissible spongiform encephalopathies, propagate by self-perpetuating the structural information stored in the abnormally folded, aggregated conformer (PrPSc of the host-encoded prion protein (PrPC. To date, no structural model related to prion assembly organization satisfactorily describes how strain-specified structural information is encoded and by which mechanism this information is transferred to PrPC. To achieve progress on this issue, we correlated the PrPSc quaternary structural transition from three distinct prion strains during unfolding and refolding with their templating activity. We reveal the existence of a mesoscopic organization in PrPSc through the packing of a highly stable oligomeric elementary subunit (suPrP, in which the strain structural determinant (SSD is encoded. Once kinetically trapped, this elementary subunit reversibly loses all replicative information. We demonstrate that acquisition of the templating interface and infectivity requires structural rearrangement of suPrP, in concert with its condensation. The existence of such an elementary brick scales down the SSD support to a small oligomer and provide a basis of reflexion for prion templating process and propagation.

  18. CDC WONDER: Mortality - Infant Deaths

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Mortality - Infant Deaths (from Linked Birth / Infant Death Records) online databases on CDC WONDER provide counts and rates for deaths of children under 1 year...

  19. [Deaths in hotels].

    Science.gov (United States)

    Risse, Manfred; Weilbächer, Nadine; Birngruber, Christoph; Verhoff, Marcel A

    2010-01-01

    There are no verified statistics about deaths occurring in hotels, and only a few cases have been described in the literature. A recent case induced us to conduct a systematic search for deaths in hotels in the autopsy reports of the Institute of Legal Medicine in Giessen for the period from 1968 to 2009. This search yielded 22 evaluable cases in which persons had been found dead or had died in hotels. Data evaluated in the study were sex and age of the deceased, reason for the stay in the hotel and cause of death. Among the deaths, 18 were males and 4 females and the average age was 41 and 40 years respectively. 6 of the male guests had died from a natural and 10 from a non-natural cause. In the remaining two cases, the cause of death could not be determined, but as there was no evidence that another party had been involved, the cases were not further investigated. Of the 4 female guests, 3 had died of a natural cause; in one case, the cause of death remained unclear even after morphological and toxicological investigations. Surprisingly, a third of the men were found to be temporarily living in hotels due to social circumstances. This was not true for any of the women. Our retrospective analysis is based on a comparatively small number of deaths in what were mostly hotels in small to medium-sized towns. Interestingly, the gender ratio of 18:4 for deceased men and women was significantly higher than the usual gender ratio of 2:1 found for forensic autopsies. To be able to draw further conclusions, a greater number of cases would have to be analysed, for example by recruiting additional case files from other institutes of legal medicine. This would also open up the option of investigating possible regional variations.

  20. Life and death.

    Science.gov (United States)

    Lloyd, J W

    1983-03-01

    In contrast with the other lectures given in the course on humanics and bioethics at the UOEH, which address the questions of life and death from the standpoint of the physician or the philosopher, this lecture considers these issues as seen by the cancer patient who has had a close encounter with death. The attitudes of Americans concerning abortion, the use of life-support systems, "mercy killings", suicide and the use of cancer chemotherapy are discussed with particular emphasis on restraints imposed by the courts, the churches and the family systems. An attempt is made to contrast the American and Japanese attitudes on these questions but this is difficult because of different cultural and religious backgrounds. The author describes his own experiences as a cancer patient who has approached death very closely and the changes in his own attitude toward life which results from the encounter with death. He also talks about the joy of being alive and describes his own experience with receiving cancer chemotherapy, the resulting discomfort and inconveniences and his feelings about a "tolerable" existence. Finally, the author considers the question of the "quality of life" for the cancer patient who has a violent reaction to certain forms of chemotherapy. This is a dilemma for the patient and the doctor who must consider the choice between death and a miserable existence.

  1. Malnutrition related deaths.

    Science.gov (United States)

    Sparre-Sørensen, Maja; Kristensen, Gustav N

    2016-10-01

    Studies have shown that malnutrition increases the risk of morbidity, mortality, the length of hospital stay, and costs in the elderly population. Approximately one third of all patients admitted to geriatric wards in Denmark are malnourished according to the Danish Geriatric database. The aim of this study is to describe and examine the sudden increase in deaths due to malnutrition in the elderly population in Denmark from 1999 and, similarly, the sudden decline in malnutrition related deaths in 2007. A descriptive epidemiologic study was performed. All Danes listed in the national death registry who died from malnutrition in the period from 1994 to 2012 are included. The number of deaths from malnutrition increased significantly during the period from 1999 to 2007, especially in the age group 70 years and over. Additionally, we document a surprising similarity between the development in excess mortality from malnutrition in the five Danish regions during the same period. During the period 1999-2007 malnutrition was the direct cause of 340 extra deaths, and probably ten times more registered under other diseases. This development in excess mortality runs parallel in all five Danish regions over time. Copyright © 2016 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.

  2. Concept of 'bad death'

    Directory of Open Access Journals (Sweden)

    Marija Vučković

    2016-02-01

    Full Text Available Following previous research on the linguistic concept of а 'bad death' which lexical expression is the word family of the verb ginuti, I focus my attention in this paper on the relationship between language conceptualization of а 'bad death' and the representation of а 'bad death' in traditional and contemporary culture. Diachronically based language corpus makes possible to trace the changes of referential frame and use of verb ginuti and its derivatives. In the traditional culture а 'bad death' is marked in action code by irregular way of burial and beliefs in demons stemming from the 'impure dead'. In the paper I explore the degree of synonymy of the symbols of all three codes: verbal code, action code and code of beliefs. In the contemporary culture the lack of individual control and choice is considered to be the key element of the concept of a 'bad death'. This change of conceptual content manifests itself in the use of its lexical expressions.

  3. Precisely Tracking Childhood Death.

    Science.gov (United States)

    Farag, Tamer H; Koplan, Jeffrey P; Breiman, Robert F; Madhi, Shabir A; Heaton, Penny M; Mundel, Trevor; Ordi, Jaume; Bassat, Quique; Menendez, Clara; Dowell, Scott F

    2017-07-01

    Little is known about the specific causes of neonatal and under-five childhood death in high-mortality geographic regions due to a lack of primary data and dependence on inaccurate tools, such as verbal autopsy. To meet the ambitious new Sustainable Development Goal 3.2 to eliminate preventable child mortality in every country, better approaches are needed to precisely determine specific causes of death so that prevention and treatment interventions can be strengthened and focused. Minimally invasive tissue sampling (MITS) is a technique that uses needle-based postmortem sampling, followed by advanced histopathology and microbiology to definitely determine cause of death. The Bill & Melinda Gates Foundation is supporting a new surveillance system called the Child Health and Mortality Prevention Surveillance network, which will determine cause of death using MITS in combination with other information, and yield cause-specific population-based mortality rates, eventually in up to 12-15 sites in sub-Saharan Africa and south Asia. However, the Gates Foundation funding alone is not enough. We call on governments, other funders, and international stakeholders to expand the use of pathology-based cause of death determination to provide the information needed to end preventable childhood mortality.

  4. [Reflections on prehospitalisation deaths].

    Science.gov (United States)

    Hugenschmitt, Delphine; Allonneau, Alexandre; Cesareo, Éric; Gueugniaud, Pierre-Yves; Lefort, Hugues

    2017-12-01

    In the past, death was a family and community affair, but today it is institutional and entrusted to healthcare personnel. Thanks to a questionnaire on their feelings about prehospitalisation deaths, the experience and training needs for healthcare personnel at a mobile emergency and intensive care service were analysed. The majority of these professionals had been confronted with difficulties when faced with prehospitalisation deaths. There is little understanding of religious rites, even though this is an important point in dealing with the situation. There is a strong desire for training. The pedagogical support offered in response to the needs expressed was recognised as being useful and should be more widespread. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. Amphetamine derivative related deaths.

    Science.gov (United States)

    Lora-Tamayo, C; Tena, T; Rodríguez, A

    1997-02-28

    Amphetamine its methylendioxy (methylendioxyamphetamine methylenedioxymethylamphetamine, methylenedioxyethylamphetamine) and methoxy derivatives (p-methoxyamphetamine and p-methoxymethylamphetamine) are widely abused in Spanish society. We present here the results of a systematic study of all cases of deaths brought to the attention of the Madrid department of the Instituto Nacional de Toxicologia from 1993 to 1995 in which some of these drugs have been found in the cadaveric blood. The cases were divided into three categories: amphetamine and derivatives, amphetamines and alcohol, amphetamines and other drugs. Data on age, sex, clinical symptoms, morphological findings, circumstances of death, when known, and concentration of amphetamine derivatives, alcohol and other drugs in blood are given for each group. The information provided here may prove to be useful for the forensic interpretation of deaths which are directly or indirectly related to abuse of amphetamine derivatives.

  6. Competing causes of death: a death certificate study

    NARCIS (Netherlands)

    Mackenbach, J. P.; Kunst, A. E.; Lautenbach, H.; Oei, Y. B.; Bijlsma, F.

    1997-01-01

    BACKGROUND: Despite the widespread interest in competing causes of death, empirical information on interrelationships between causes of death is scarce. We have used death certificate information to estimate the prevalence of competing causes of death at the moment of dying from specific underlying

  7. Effect of the electrostatic surface potential on the oligomerization of full-length human recombinant prion protein at single-molecule level

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bin; Xu, Bingqian, E-mail: bxu@engr.uga.edu [Single Molecule Study Laboratory, College of Engineering and Nanoscale Science, and Engineering Center, University of Georgia, Athens, Georgia 30605 (United States); Lou, Zhichao [Single Molecule Study Laboratory, College of Engineering and Nanoscale Science, and Engineering Center, University of Georgia, Athens, Georgia 30605 (United States); College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Zhang, Haiqian [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2016-03-21

    The electrostatic surface potential (ESP) of prion oligomers has critical influences on the aggregating processes of the prion molecules. The atomic force microscopy (AFM) and structural simulation were combined to investigate the molecular basis of the full-length human recombinant prion oligomerization on mica surfaces. The high resolution non-intrusive AFM images showed that the prion oligomers formed different patterns on mica surfaces at different buffer pH values. The basic binding units for the large oligomers were determined to be prion momoners (Ms), dimers (Ds), and trimers (Ts). The forming of the D and T units happened through the binding of hydrophobic β-sheets of the M units. In contrast, the α-helices of these M, D, and T units were the binding areas for the formation of large oligomers. At pH 4.5, the binding units M, D, and T showed clear polarized ESP distributions on the surface domains, while at pH 7.0, they showed more evenly distributed ESPs. Based on the conformations of oligomers observed from AFM images, the D and T units were more abundantly on mica surface at pH 4.5 because the ESP re-distribution of M units helped to stabilize these larger oligomers. The amino acid side chains involved in the binding interfaces were stabilized by hydrogen bonds and electrostatic interactions. The detailed analysis of the charged side chains at pH 4.5 indicated that the polarized ESPs induced the aggregations among M, D, and T to form larger oligomers. Therefore, the hydrogen bonds and electrostatic interactions worked together to form the stabilized prion oligomers.

  8. Effect of the electrostatic surface potential on the oligomerization of full-length human recombinant prion protein at single-molecule level

    International Nuclear Information System (INIS)

    Wang, Bin; Xu, Bingqian; Lou, Zhichao; Zhang, Haiqian

    2016-01-01

    The electrostatic surface potential (ESP) of prion oligomers has critical influences on the aggregating processes of the prion molecules. The atomic force microscopy (AFM) and structural simulation were combined to investigate the molecular basis of the full-length human recombinant prion oligomerization on mica surfaces. The high resolution non-intrusive AFM images showed that the prion oligomers formed different patterns on mica surfaces at different buffer pH values. The basic binding units for the large oligomers were determined to be prion momoners (Ms), dimers (Ds), and trimers (Ts). The forming of the D and T units happened through the binding of hydrophobic β-sheets of the M units. In contrast, the α-helices of these M, D, and T units were the binding areas for the formation of large oligomers. At pH 4.5, the binding units M, D, and T showed clear polarized ESP distributions on the surface domains, while at pH 7.0, they showed more evenly distributed ESPs. Based on the conformations of oligomers observed from AFM images, the D and T units were more abundantly on mica surface at pH 4.5 because the ESP re-distribution of M units helped to stabilize these larger oligomers. The amino acid side chains involved in the binding interfaces were stabilized by hydrogen bonds and electrostatic interactions. The detailed analysis of the charged side chains at pH 4.5 indicated that the polarized ESPs induced the aggregations among M, D, and T to form larger oligomers. Therefore, the hydrogen bonds and electrostatic interactions worked together to form the stabilized prion oligomers.

  9. Effect of the electrostatic surface potential on the oligomerization of full-length human recombinant prion protein at single-molecule level

    Science.gov (United States)

    Wang, Bin; Lou, Zhichao; Zhang, Haiqian; Xu, Bingqian

    2016-03-01

    The electrostatic surface potential (ESP) of prion oligomers has critical influences on the aggregating processes of the prion molecules. The atomic force microscopy (AFM) and structural simulation were combined to investigate the molecular basis of the full-length human recombinant prion oligomerization on mica surfaces. The high resolution non-intrusive AFM images showed that the prion oligomers formed different patterns on mica surfaces at different buffer pH values. The basic binding units for the large oligomers were determined to be prion momoners (Ms), dimers (Ds), and trimers (Ts). The forming of the D and T units happened through the binding of hydrophobic β-sheets of the M units. In contrast, the α-helices of these M, D, and T units were the binding areas for the formation of large oligomers. At pH 4.5, the binding units M, D, and T showed clear polarized ESP distributions on the surface domains, while at pH 7.0, they showed more evenly distributed ESPs. Based on the conformations of oligomers observed from AFM images, the D and T units were more abundantly on mica surface at pH 4.5 because the ESP re-distribution of M units helped to stabilize these larger oligomers. The amino acid side chains involved in the binding interfaces were stabilized by hydrogen bonds and electrostatic interactions. The detailed analysis of the charged side chains at pH 4.5 indicated that the polarized ESPs induced the aggregations among M, D, and T to form larger oligomers. Therefore, the hydrogen bonds and electrostatic interactions worked together to form the stabilized prion oligomers.

  10. [Maternal death: unequal risks].

    Science.gov (United States)

    Defossez, A C; Fassin, D

    1989-01-01

    Nearly 99% of maternal deaths in the world each year occur in developing countries. New efforts have recently been undertaken to combat maternal mortality through research and action. The medical causes of such deaths are coming to be better understood, but the social mechanisms remain poorly grasped. Maternal mortality rates in developing countries are difficult to interpret because they tend to exclude all deaths not occurring in health care facilities. The countries of Europe and North America have an average maternal mortality rate of 30/100,000 live births, representing about 6000 deaths each year. The developing countries of Asia, Africa, and Latin America have rates of 270-640/100,000, representing some 492,000 deaths annually. For a true comparison of the risks of maternal mortality in different countries, the risk itself and the average number of children per woman must both be considered. A Nigerian woman has 375 times greater risk of maternal death than a Swedish woman, but since she has about 4 times more children, her lifetime risk of maternal death is over 1500 times greater than that of the Swedish woman. The principal medical causes of maternal death are known: hemorrhages due to placenta previa or retroplacental hematoma, mechanical dystocias responsible for uterine rupture, toxemia with eclampsia, septicemia, and malaria. The exact weight of abortion in maternal mortality is not known but is probably large. The possible measures for improving such rates are of 3 types: control of fertility to avoid early, late, or closely spaced pregnancies; effective medical surveillance of the pregnancy to reduce the risk of malaria, toxemia, and hemorrhage, and delivery in an obstetrical facility, especially for high-risk pregnancies. Differential access to high quality health care explains much of the difference between mortality rates in urban and rural, wealthy and impoverished areas of the same country. The social determinants of high maternal mortality

  11. Death with dignity

    OpenAIRE

    Allmark, P.

    2002-01-01

    The purpose of this article is to develop a conception of death with dignity and to examine whether it is vulnerable to the sort of criticisms that have been made of other conceptions. In this conception "death" is taken to apply to the process of dying; "dignity" is taken to be something that attaches to people because of their personal qualities. In particular, someone lives with dignity if they live well (in accordance with reason, as Aristotle would see it). It follows that health care pr...

  12. The PH Domain of PDK1 Exhibits a Novel, Phospho-Regulated Monomer-Dimer Equilibrium With Important Implications for Kinase Domain Activation: Single Molecule and Ensemble Studies†

    Science.gov (United States)

    Ziemba, Brian P.; Pilling, Carissa; Calleja, Véronique; Larijani, Banafshé; Falke, Joseph J.

    2013-01-01

    Phosphoinositide-Dependent Kinase-1 (PDK1) is an essential master kinase recruited to the plasma membrane by the binding of its C-terminal PH domain to the signaling lipid phosphatidylinositol-3,4-5-trisphosphate (PIP3). Membrane binding leads to PDK1 phospho-activation, but despite the central role of PDK1 in signaling and cancer biology this activation mechanism remains poorly understood. PDK1 has been shown to exist as a dimer in cells, and one crystal structure of its isolated PH domain exhibits a putative dimer interface. It has been proposed that phosphorylation of PH domain residue T513 (or the phospho-mimetic T513E mutation) may regulate a novel PH domain dimer-monomer equilibrium, thereby converting an inactive PDK1 dimer to an active monomer. However, the oligomeric state(s) of the PH domain on the membrane have not yet been determined, nor whether a negative charge at position 513 is sufficient to regulate its oligomeric state. The present study investigates the binding of purified WT and T513E PDK1 PH domains to lipid bilayers containing the PIP3 target lipid, using both single molecule and ensemble measurements. Single molecule analysis of the brightness of fluorescent PH domain shows that the PIP3-bound WT PH domain on membranes is predominantly dimeric, while the PIP3-bound T513E PH domain is monomeric, demonstrating that negative charge at the T513 position is sufficient to dissociate the PH domain dimer and is thus likely to play a central role in PDK1 monomerization and activation. Single molecule analysis of 2-D diffusion of PH domain-PIP3 complexes reveals that the dimeric WT PH domain diffuses at the same rate a single lipid molecule, indicating that only one of its two PIP3 binding sites is occupied and there is little protein penetration into the bilayer as observed for other PH domains. The 2-D diffusion of T513E PH domain is slower, suggesting the negative charge disrupts local structure in a way that enables greater protein insertion into

  13. Structure of the EMMPRIN N-terminal domain 1: Dimerization via [beta]-strand swapping

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Jinquan; Teplyakov, Alexey; Obmolova, Galina; Malia, Thomas; Wu, Sheng-Jiun; Beil, Eric; Baker, Audrey; Swencki-Underwood, Bethany; Zhao, Yonghong; Sprenkle, Justin; Dixon, Ken; Sweet, Raymond; Gilliland, Gary L.; (Centocor)

    2010-09-27

    ECD. Quite unexpectedly, ND1 forms a dimer mediated through the exchange of its last {beta}-strand (strand G). {beta}-strand swapping, which is a subset of 3D domain swapping, has been found to mediate cell-cell adhesion by cadherins. 3D domain swapping has been proposed to be a mechanism of protein oligomerization, aggregation, evolution of oligomeric proteins from single domains and amyloidogenesis. In domain swapped proteins, the same structural elements are involved in the final 3D structure, and so there is little overall energetic difference between the monomer and the swapped oligomers. However, there is often a high energy barrier for the conversion as it often goes through an unfolded state. It is also possible that strand-swapping occurs during folding of nascent polypeptide chains. Frequently, the exchange hinges contain proline-rich motifs which are often in high strain conformations. Domain swapping appears to be a strategy to resolve such local structural strain. The exchange hinge of ND1 contains a Pro-Glu-Pro tripeptide motif. Both of the proline residues adopt extended trans conformations, when compared with cis in the full-length ECD structure. Proline cis-trans isomerization may be the driving force for this exchange. Strand-exchanged dimerization may be a mechanism for the oligomerization of EMMPRIN ECD and its cis-dependent homophilic interactions in cell-cell adhesion.

  14. Structural fingerprints and their evolution during oligomeric vs. oligomer-free amyloid fibril growth.

    Science.gov (United States)

    Foley, Joseph; Hill, Shannon E; Miti, Tatiana; Mulaj, Mentor; Ciesla, Marissa; Robeel, Rhonda; Persichilli, Christopher; Raynes, Rachel; Westerheide, Sandy; Muschol, Martin

    2013-09-28

    Deposits of fibrils formed by disease-specific proteins are the molecular hallmark of such diverse human disorders as Alzheimer's disease, type II diabetes, or rheumatoid arthritis. Amyloid fibril formation by structurally and functionally unrelated proteins exhibits many generic characteristics, most prominently the cross β-sheet structure of their mature fibrils. At the same time, amyloid formation tends to proceed along one of two separate assembly pathways yielding either stiff monomeric filaments or globular oligomers and curvilinear protofibrils. Given the focus on oligomers as major toxic species, the very existence of an oligomer-free assembly pathway is significant. Little is known, though, about the structure of the various intermediates emerging along different pathways and whether the pathways converge towards a common or distinct fibril structures. Using infrared spectroscopy we probed the structural evolution of intermediates and late-stage fibrils formed during in vitro lysozyme amyloid assembly along an oligomeric and oligomer-free pathway. Infrared spectroscopy confirmed that both pathways produced amyloid-specific β-sheet peaks, but at pathway-specific wavenumbers. We further found that the amyloid-specific dye thioflavin T responded to all intermediates along either pathway. The relative amplitudes of thioflavin T fluorescence responses displayed pathway-specific differences and could be utilized for monitoring the structural evolution of intermediates. Pathway-specific structural features obtained from infrared spectroscopy and Thioflavin T responses were identical for fibrils grown at highly acidic or at physiological pH values and showed no discernible effects of protein hydrolysis. Our results suggest that late-stage fibrils formed along either pathway are amyloidogenic in nature, but have distinguishable structural fingerprints. These pathway-specific fingerprints emerge during the earliest aggregation events and persist throughout the

  15. Bioactivity and properties of a dental adhesive functionalized with polyhedral oligomeric silsesquioxanes (POSS) and bioactive glass.

    Science.gov (United States)

    Rizk, Marta; Hohlfeld, Lisa; Thanh, Loan Tao; Biehl, Ralf; Lühmann, Nicole; Mohn, Dirk; Wiegand, Annette

    2017-09-01

    This study aimed to analyze the effect of infiltrating a commercial adhesive with nanosized bioactive glass (BG-Bi) particles or methacryl-functionalized polyhedral oligomeric silsesquioxanes (POSS) on material properties and bioactivity. An acetone-based dental adhesive (Solobond Plus adhesive, VOCO GmbH, Cuxhaven, Germany) was infiltrated with nanosized bioactive glass particles (0.1 or 1wt%), or with monofunctional or multifunctional POSS particles (10 or 20wt%). Unfilled adhesive served as control. Dispersion and hydrodynamic radius of the nanoparticles were studied by dynamic light scattering. Set specimens were immersed for 28days in artificial saliva at 37°C, and surfaces were mapped for the formation of calcium phospate (Ca/P) precipitates (scanning electron microscopy/energy-dispersive X-ray spectroscopy). Viscosity (rheometry) and the structural characteristic of the networks were studied, such as degree of conversion (FTIR spectroscopy), sol fraction and water sorption. POSS particles showed a good dispersion of the particles for both types of particles being smaller than 3nm, while the bioactive glass particles had a strong tendency to agglomerate. All nanoparticles induced the formation of Ca/P precipitates. The viscosity of the adhesive was not or only slightly increased by POSS particle addition but strongly increased by the bioactive glass particles. The degree of conversion, water sorption and sol fraction showed a maintained or improved network structure and properties when filled with BG-Bi and multifunctional POSS, however, less polymerization was found when loading a monofunctional POSS. Multifunctional POSS may be incorporated into dental adhesives to provide a bioactive potential without changing material properties adversely. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  16. Cartilage oligomeric matrix protein enhances matrix assembly during chondrogenesis of human mesenchymal stem cells.

    Science.gov (United States)

    Haleem-Smith, Hana; Calderon, Raul; Song, Yingjie; Tuan, Rocky S; Chen, Faye H

    2012-04-01

    Cartilage oligomeric matrix protein/thrombospondin-5 (COMP/TSP5) is an abundant cartilage extracellular matrix (ECM) protein that interacts with major cartilage ECM components, including aggrecan and collagens. To test our hypothesis that COMP/TSP5 functions in the assembly of the ECM during cartilage morphogenesis, we have employed mesenchymal stem cell (MSC) chondrogenesis in vitro as a model to examine the effects of COMP over-expression on neo-cartilage formation. Human bone marrow-derived MSCs were transfected with either full-length COMP cDNA or control plasmid, followed by chondrogenic induction in three-dimensional pellet or alginate hydrogel culture. MSC chondrogenesis and ECM production was estimated based on quantitation of sulfated glycosaminoglycan (sGAG) accumulation, immunohistochemistry of the presence and distribution of cartilage ECM proteins, and real-time RT-PCR analyis of mRNA expression of cartilage markers. Our results showed that COMP over-expression resulted in increased total sGAG content during the early phase of MSC chondrogenesis, and increased immuno-detectable levels of aggrecan and collagen type II in the ECM of COMP-transfected pellet and alginate cultures, indicating more abundant cartilaginous matrix. COMP transfection did not significantly increase the transcript levels of the early chondrogenic marker, Sox9, or aggrecan, suggesting that enhancement of MSC cartilage ECM was effected at post-transcriptional levels. These findings strongly suggest that COMP functions in mesenchymal chondrogenesis by enhancing cartilage ECM organization and assembly. The action of COMP is most likely mediated not via direct changes in cartilage matrix gene expression but via interactions of COMP with other cartilage ECM proteins, such as aggrecan and collagens, that result in enhanced assembly and retention.

  17. Binding and Oligomerization of Modified and Native Bt Toxins in Resistant and Susceptible Pink Bollworm.

    Directory of Open Access Journals (Sweden)

    Josue Ocelotl

    Full Text Available Insecticidal proteins from Bacillus thuringiensis (Bt are used extensively in sprays and transgenic crops for pest control, but their efficacy is reduced when pests evolve resistance. Better understanding of the mode of action of Bt toxins and the mechanisms of insect resistance is needed to enhance the durability of these important alternatives to conventional insecticides. Mode of action models agree that binding of Bt toxins to midgut proteins such as cadherin is essential for toxicity, but some details remain unresolved, such as the role of toxin oligomers. In this study, we evaluated how Bt toxin Cry1Ac and its genetically engineered counterpart Cry1AcMod interact with brush border membrane vesicles (BBMV from resistant and susceptible larvae of Pectinophora gossypiella (pink bollworm, a global pest of cotton. Compared with Cry1Ac, Cry1AcMod lacks 56 amino acids at the amino-terminus including helix α-1; previous work showed that Cry1AcMod formed oligomers in vitro without cadherin and killed P. gossypiella larvae harboring cadherin mutations linked with >1000-fold resistance to Cry1Ac. Here we found that resistance to Cry1Ac was associated with reduced oligomer formation and insertion. In contrast, Cry1AcMod formed oligomers in BBMV from resistant larvae. These results confirm the role of cadherin in oligomerization of Cry1Ac in susceptible larvae and imply that forming oligomers without cadherin promotes toxicity of Cry1AcMod against resistant P. gossypiella larvae that have cadherin mutations.

  18. Structure–property relationships in hybrid dental nanocomposite resins containing monofunctional and multifunctional polyhedral oligomeric silsesquioxanes

    Directory of Open Access Journals (Sweden)

    Wang WG

    2014-02-01

    Full Text Available Weiguo Wang,1,* Xiang Sun,1,* Li Huang,2,* Yu Gao,1 Jinghao Ban,1 Lijuan Shen,1 Jihua Chen1 1Department of Prosthodontics, 2Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi'an, People's Republic of China*These authors contributed equally to this workAbstract: Organic-inorganic hybrid materials, such as polyhedral oligomeric silsesquioxanes (POSS, have the potential to improve the mechanical properties of the methacrylate-based composites and resins used in dentistry. In this article, nanocomposites of methacryl isobutyl POSS (MI-POSS [bears only one methacrylate functional group] and methacryl POSS (MA-POSS [bears eight methacrylate functional groups] were investigated to determine the effect of structures on the properties of dental resin. The structures of the POSS-containing networks were determined by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Monofunctional POSS showed a strong tendency toward aggregation and crystallization, while multifunctional POSS showed higher miscibility with the dimethacrylate monomer. The mechanical properties and wear resistance decreased with increasing amounts of MI-POSS, indicating that the MI-POSS agglomerates act as the mechanical weak point in the dental resins. The addition of small amounts of MA-POSS improved the mechanical and shrinkage properties. However, samples with a higher MA-POSS concentration showed lower flexural strength and flexural modulus, indicating that there is a limited range in which the reinforcement properties of MA-POSS can operate. This concentration dependence is attributed to phase separation at higher concentrations of POSS, which affects the structural integrity, and thus, the mechanical and shrinkage properties of the dental resin. Our results show that resin with 3% MA-POSS is a potential candidate for resin-based dental materials

  19. Morphological evolution in dewetting polystyrene/polyhedral oligomeric silsesquioxane thin film bilayers.

    Science.gov (United States)

    Paul, Rituparna; Karabiyik, Ufuk; Swift, Michael C; Hottle, John R; Esker, Alan R

    2008-05-06

    Morphological evolution in dewetting thin film bilayers of polystyrene (PS) and a polyhedral oligomeric silsesquioxane (POSS), trisilanolphenyl-POSS (TPP), was studied as a function of annealing temperature and annealing time. The results demonstrate unique dewetting morphologies in PS/TPP bilayers at elevated temperatures that are significantly different from those typically observed in dewetting polymer/polymer bilayers. During temperature ramp studies by optical microscopy (OM) in the reflection mode, PS/TPP bilayers form cracks with a weak optical contrast at approximately 130 degrees C. The crack formation is attributed to tensile stresses within the upper TPP layer. The weak optical contrast of the cracks observed in the bilayers for annealing temperatures below approximately 160 degrees C is consistent with the cracking and dewetting of only the upper TPP layer from the underlying PS layer. The optical contrast of the morphological features is significantly enhanced at annealing temperatures of >160 degrees C. This observation suggests dewetting of both the upper TPP and the lower PS layers that results in the exposure of the silicon substrate. Upon annealing the PS/TPP bilayers at 200 degrees C in a temperature jump experiment, the upper TPP layer undergoes instantaneous cracking as observed by OM. These cracks in the upper TPP layer serve as nucleation sites for rapid dewetting and aggregation of the TPP layer, as revealed by OM and atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) results indicated that dewetting of the lower PS layer ensued for annealing times >5 min and progressed up to 90 min. For annealing times >90 min, OM, AFM, and XPS results revealed complete dewetting of both the layers with the formation of TPP encapsulated PS droplets.

  20. Endohedral complexes of Polyhedral Oligomeric Silsesquioxane (POSS) cages with transition metal dihydrides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiqiao; Corn, John; Hagelberg, Frank, E-mail: hagelber@etsu.edu

    2013-11-29

    Highlights: • Comparative studies of POSS cages with endohedral metal dihydrides. • Exothermic inclusion was found for the T{sub 10} cage with MH{sub 2}, M = Ti, Ru, Os, Pt. • Within this group of metal atoms, the only exothermic MH{sub 4}@T{sub m} unit is that with M = Os. • Enhanced hydrogen atom density, as compared to free MH{sub 4}, was found in the cage. • No exothermic solutions were identified for MH{sub 6}@T{sub 10}. - Abstract: Polyhedral Oligomeric Silsesquioxane (POSS) cages are investigated in terms of their potential to enclose small metal hydrides, with the objective of defining conditions that maximize the number of encapsulated hydrogen atoms. Systems of the form MH{sub 2n}@T{sub m}, where n = 1–3, m = 8, 10, and M comprises metal atom species of the groups IV, VI, VIII, X, and XII, are studied by methods of ab initio and density functional theory (DFT). The resulting composites are categorized with respect to their structural and energetic features. For MH{sub 2}@T{sub 8}, it is found in all cases considered that including MH{sub 2} into the POSS cage is an endothermic process. For MH{sub 2}@T{sub 10} and M = Ti, Ru, Os, Pt, inclusion of the MH{sub 2} guest into the cage turns out to be exothermic, and also leaves the cage intact. For MH{sub 4}@T{sub m}, this behavior is only observed for one system, OsH{sub 4}@T{sub 10}.

  1. Structural fingerprints and their evolution during oligomeric vs. oligomer-free amyloid fibril growth

    Science.gov (United States)

    Foley, Joseph; Hill, Shannon E.; Miti, Tatiana; Mulaj, Mentor; Ciesla, Marissa; Robeel, Rhonda; Persichilli, Christopher; Raynes, Rachel; Westerheide, Sandy; Muschol, Martin

    2013-09-01

    Deposits of fibrils formed by disease-specific proteins are the molecular hallmark of such diverse human disorders as Alzheimer's disease, type II diabetes, or rheumatoid arthritis. Amyloid fibril formation by structurally and functionally unrelated proteins exhibits many generic characteristics, most prominently the cross β-sheet structure of their mature fibrils. At the same time, amyloid formation tends to proceed along one of two separate assembly pathways yielding either stiff monomeric filaments or globular oligomers and curvilinear protofibrils. Given the focus on oligomers as major toxic species, the very existence of an oligomer-free assembly pathway is significant. Little is known, though, about the structure of the various intermediates emerging along different pathways and whether the pathways converge towards a common or distinct fibril structures. Using infrared spectroscopy we probed the structural evolution of intermediates and late-stage fibrils formed during in vitro lysozyme amyloid assembly along an oligomeric and oligomer-free pathway. Infrared spectroscopy confirmed that both pathways produced amyloid-specific β-sheet peaks, but at pathway-specific wavenumbers. We further found that the amyloid-specific dye thioflavin T responded to all intermediates along either pathway. The relative amplitudes of thioflavin T fluorescence responses displayed pathway-specific differences and could be utilized for monitoring the structural evolution of intermediates. Pathway-specific structural features obtained from infrared spectroscopy and Thioflavin T responses were identical for fibrils grown at highly acidic or at physiological pH values and showed no discernible effects of protein hydrolysis. Our results suggest that late-stage fibrils formed along either pathway are amyloidogenic in nature, but have distinguishable structural fingerprints. These pathway-specific fingerprints emerge during the earliest aggregation events and persist throughout the

  2. CARTILAGE OLIGOMERIC MATRIX PROTEIN ENHANCES MATRIX ASSEMBLY DURING CHONDROGENESIS OF HUMAN MESENCHYMAL STEM CELLS

    Science.gov (United States)

    Haleem-Smith, Hana; Calderon, Raul; Song, Yingjie; Tuan, Rocky S.; Chen, Faye H.

    2011-01-01

    Cartilage oligomeric matrix protein/thrombospondin-5 (COMP/TSP5) is an abundant cartilage extracellular matrix (ECM) protein that interacts with major cartilage ECM components, including aggrecan and collagens. To test our hypothesis that COMP/TSP5 functions in the assembly of the ECM during cartilage morphogenesis, we have employed mesenchymal stem cell (MSC) chondrogenesis in vitro as a model to examine the effects of COMP over-expression on neo-cartilage formation. Human bone marrow-derived MSCs were transfected with either full-length COMP cDNA or control plasmid, followed by chondrogenic induction in three-dimensional pellet or alginate-hydrogel culture. MSC chondrogenesis and ECM production was estimated based on quantitation of sulfated glycosaminoglycan (sGAG) accumulation, immunohistochemistry of the presence and distribution of cartilage ECM proteins, and real-time RT-PCR analyis of mRNA expression of cartilage markers. Our results showed that COMP over-expression resulted in increased total sGAG content during the early phase of MSC chondrogenesis, and increased immuno-detectable levels of aggrecan and collagen type II in the ECM of COMP-transfected pellet and alginate cultures, indicating more abundant cartilaginous matrix. COMP transfection did not significantly increase the transcript levels of the early chondrogenic marker, Sox9, or aggrecan, suggesting that enhancement of MSC cartilage ECM was effected at post-transcriptional levels. These findings strongly suggest that COMP functions in mesenchymal chondrogenesis by enhancing cartilage ECM organization and assembly. The action of COMP is most likely mediated not via direct changes in cartilage matrix gene expression but via interactions of COMP with other cartilage ECM proteins, such as aggrecan and collagens, that result in enhanced assembly and retention. PMID:22095699

  3. Reversibility and two state behaviour in the thermal unfolding of oligomeric TIM barrel proteins.

    Science.gov (United States)

    Romero-Romero, Sergio; Costas, Miguel; Rodríguez-Romero, Adela; Alejandro Fernández-Velasco, D

    2015-08-28

    Temperature is one of the main variables that modulate protein function and stability. Thermodynamic studies of oligomeric proteins, the dominant protein natural form, have been often hampered because irreversible aggregation and/or slow reactions are common. There are no reports on the reversible equilibrium thermal unfolding of proteins composed of (β/α)8 barrel subunits, albeit this "TIM barrel" topology is one of the most abundant and versatile in nature. We studied the eponymous TIM barrel, triosephosphate isomerase (TIM), belonging to five species of different bacterial taxa. All of them were found to be catalytically efficient dimers. The three-dimensional structure of four enzymes was solved at high/medium resolution. Irreversibility and kinetic control were observed in the thermal unfolding of two TIMs, while for the other three the thermal unfolding was found to follow a two-state equilibrium reversible process. Shifts in the global stability curves of these three proteins are related to the organismal temperature range of optimal growth and modulated by variations in maximum stability temperature and in the enthalpy change at that temperature. Reversibility appears to correlate with the low isoelectric point, the absence of a residual structure in the unfolded state, small cavity volume in the native state, low conformational stability and a low melting temperature. Furthermore, the strong coupling between dimer dissociation and monomer unfolding may reduce aggregation and favour reversibility. It is therefore very thought-provoking to find that a common topological ensemble, such as the TIM barrel, can unfold/refold in the Anfinsen way, i.e. without the help of the cellular machinery.

  4. High-Performance Oligomeric Catholytes for Effective Macromolecular Separation in Nonaqueous Redox Flow Batteries.

    Science.gov (United States)

    Hendriks, Koen H; Robinson, Sophia G; Braten, Miles N; Sevov, Christo S; Helms, Brett A; Sigman, Matthew S; Minteer, Shelley D; Sanford, Melanie S

    2018-02-28

    Nonaqueous redox flow batteries (NRFBs) represent an attractive technology for energy storage from intermittent renewable sources. In these batteries, electrical energy is stored in and extracted from electrolyte solutions of redox-active molecules (termed catholytes and anolytes) that are passed through an electrochemical flow cell. To avoid battery self-discharge, the anolyte and catholyte solutions must be separated by a membrane in the flow cell. This membrane prevents crossover of the redox active molecules, while simultaneously allowing facile transport of charge-balancing ions. A key unmet challenge for the field is the design of redox-active molecule/membrane pairs that enable effective electrolyte separation while maintaining optimal battery properties. Herein, we demonstrate the development of oligomeric catholytes based on tris(dialkylamino)cyclopropenium (CP) salts that are specifically tailored for pairing with size-exclusion membranes composed of polymers of intrinsic microporosity (PIMs). Systematic studies were conducted to evaluate the impact of oligomer size/structure on properties that are crucial for flow battery performance, including cycling stability, charge capacity, solubility, electron transfer kinetics, and crossover rates. These studies have led to the identification of a CP-derived tetramer in which these properties are all comparable, or significantly improved, relative to the monomeric counterpart. Finally, a proof-of-concept flow battery is demonstrated by pairing this tetrameric catholyte with a PIM membrane. After 6 days of cycling, no crossover is detected, demonstrating the promise of this approach. These studies provide a template for the future design of other redox-active oligomers for this application.

  5. Teaching about the Death Penalty.

    Science.gov (United States)

    Ryan, John Paul; Eden, John Michael

    1998-01-01

    Examines the reasons for the death penalty, the reasons why the death penalty attracts so much attention, whether the death penalty is applied consistently, and the evidence that the application of the death penalty may be racially biased. Provides an accompanying article on "Teaching Ideas" by Ronald A. Banaszak. (CMK)

  6. Digital Language Death

    Science.gov (United States)

    Kornai, András

    2013-01-01

    Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide. PMID:24167559

  7. Digital language death.

    Directory of Open Access Journals (Sweden)

    András Kornai

    Full Text Available Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide.

  8. Death Penalty in America.

    Science.gov (United States)

    Clifford, Amie L.

    1997-01-01

    Examines the legal and moral issues, controversies, and unique trial procedures involved with the death penalty. Discusses the 1972 landmark Supreme Court decision that resulted in many states abolishing this punishment, only to reintroduce it later with different provisions. Reviews the controversial case of Sam Sheppard. (MJP)

  9. The Death Penalty.

    Science.gov (United States)

    Crockett, Mark

    1990-01-01

    Provides a lesson plan on the Eighth Amendment to the U.S. Constitution and the imposition of the death penalty. Focuses on the controversy concerning capital punishment and stimulates critical thinking in an analysis and discussion of eight hypothetical situations. Includes suggestions for readings, videotapes, and writing assignments. (NL)

  10. Optimal Aging and Death

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Strulik, Holger

    2010-01-01

    This study introduces physiological aging into a simple model of optimal intertemporal consumption. In this endeavor we draw on the natural science literature on aging. According to the purposed theory, the speed of the aging process and the time of death are endogenously determined by optimal...

  11. Optimal Aging and Death

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan; Strulik, Holger

    the representative consumer is subject to physiological aging. In modeling aging we draw on recent research in the fields of biology and medicine. The speed of the aging process, and thus the time of death, are endogenously determined by optimal health investments. We calibrate the model to US data and proceed...

  12. Preventing the White Death

    DEFF Research Database (Denmark)

    Hansen, Casper Worm; Jensen, Peter S.; Madsen, Peter

    2017-01-01

    Tuberculosis (TB) is a leading cause of death worldwide and, while treatable by antibiotics since the 1940s, drug resistant strains have emerged. This paper estimates the effects of the establishment of a pre-antibiotic era public health institution, known as a TB dispensary, designed to prevent...

  13. Disparities in death

    DEFF Research Database (Denmark)

    Molitoris, Joseph John

    2017-01-01

    and accidents, (5) perinatal causes, and (6) unspecified causes. RESULTS The results show that class differentials in nearly all causes of death converged during the demographic transition. The only exception to this was the airborne infectious disease category, for which the gap between white collar...

  14. The Death of Shankar

    DEFF Research Database (Denmark)

    Seeberg, Jens

    2013-01-01

    ) in Bhubaneswar, the capital city of Orissa. The chapter explores the heterogeneous and hierarchical composition of the basti and unfolds the case of the social exclusion and ultimate death of a patient with tuberculosis who belonged to the poorest section of the basti, called Pradhan sahi. The case of both...

  15. Death in Flames

    DEFF Research Database (Denmark)

    Harvig, Lise Lock; Kveiborg, Jacob; Lynnerup, Niels

    2015-01-01

    This paper presents osteoarchaeological analyses of the human skeletal material from a burnt down house in Jutland, Denmark, dated to the first century bc. We describe how the osteological analyses of this complex site were approached and illustrate how we reconstructed the death of the human...

  16. Sudden cardiac death

    DEFF Research Database (Denmark)

    Hougen, H P; Valenzuela, Antonio Jesus Sanchez; Lachica, E

    1992-01-01

    case was inconclusive. After studying the circumstances of death, the number of discrepancies were reduced to 20, so that concordance was reached in 86% of all the cases. The results show that the combination of different methods leads to a diagnosis of myocardial infarction in far more cases than...

  17. Bee deaths need analysing

    NARCIS (Netherlands)

    Boonekamp, P.M.

    2011-01-01

    Alarm bells are ringing all over the world about the death of bee populations. Although it is not known exactly how severe the decline is, it is important to take the problem seriously. The signals are alarming and the bee is important, not just for natural ecosystems but also for the pollination of

  18. [Death of Napoleon Bonaparte].

    Science.gov (United States)

    Camici, M

    2003-06-01

    The causa mortis of Napoleon Bonaparte has been vexata quaestio for a long time. The author tries to outline a picture of Napoleon from a sanitary point of view. From the report of doctor Francesco Antonmarchi who performed the autopsy, the author tries to understans the cause of death: gastric perforation due to malignant ulcer and subsequent peritonitis with pulmonary tubercolosis.

  19. KAROSHI (WORK TO DEATH

    Directory of Open Access Journals (Sweden)

    Moh. Toriqul Chaer

    2017-05-01

    Full Text Available When the tide of unemployment hit the USA and Europe, in Japan the opposite phenomenon occurs. In 2002, in Japan deaths were recorded because of excessive works. In this country, the phenomenon of death because of excessive works is called Karoshi. Karoshi is common in Japan.  It becomes deadly syndrome as a consequence of long hours works. The debate about deaths from excessive work already sticking out in Japan since the 70s. The first official case of Karoshi was reported in 1969 when a 29-year-old male worker died because of stroke. It is estimated over ten thousand workers died each year due to death by brain and stroke caused by an overload work. Karoshi often happen to male workers dominantly. The main cause of karoshi is stress due to high pressure in the work environment, and work habits of exceeding a  standard of normal working time (8 hours. In addition, their extra time to work is imbalance with and the salary they earn. In its development, the phenomenon of karoshi contributes to the term salaryman and workaholic.

  20. Live cell imaging unveils multiple domain requirements for in vivo dimerization of the glucocorticoid receptor.

    Directory of Open Access Journals (Sweden)

    Diego M Presman

    2014-03-01

    Full Text Available Glucocorticoids are essential for life, but are also implicated in disease pathogenesis and may produce unwanted effects when given in high doses. Glucocorticoid receptor (GR transcriptional activity and clinical outcome have been linked to its oligomerization state. Although a point mutation within the GR DNA-binding domain (GRdim mutant has been reported as crucial for receptor dimerization and DNA binding, this assumption has recently been challenged. Here we have analyzed the GR oligomerization state in vivo using the number and brightness assay. Our results suggest a complete, reversible, and DNA-independent ligand-induced model for GR dimerization. We demonstrate that the GRdim forms dimers in vivo whereas adding another mutation in the ligand-binding domain (I634A severely compromises homodimer formation. Contrary to dogma, no correlation between the GR monomeric/dimeric state and transcriptional activity was observed. Finally, the state of dimerization affected DNA binding only to a subset of GR binding sites. These results have major implications on future searches for therapeutic glucocorticoids with reduced side effects.

  1. Framing Effects: Dynamics and Task Domains

    Science.gov (United States)

    Wang

    1996-11-01

    The author examines the mechanisms and dynamics of framing effects in risky choices across three distinct task domains (i.e., life-death, public property, and personal money). The choice outcomes of the problems presented in each of the three task domains had a binary structure of a sure thing vs a gamble of equal expected value; the outcomes differed in their framing conditions and the expected values, raging from 6000, 600, 60, to 6, numerically. It was hypothesized that subjects would become more risk seeking, if the sure outcome was below their aspiration level (the minimum requirement). As predicted, more subjects preferred the gamble when facing the life-death choice problems than facing the counterpart problems presented in the other two task domains. Subjects' risk preference varied categorically along the group size dimension in the life-death domain but changed more linearly over the expected value dimension in the monetary domain. Framing effects were observed in 7 of 13 pairs of problems, showing a positive frame-risk aversion and negative frame-risk seeking relationship. In addition, two types of framing effects were theoretically defined and empirically identified. A bidirectional framing effect involves a reversal in risk preference, and occurs when a decision maker's risk preference is ambiguous or weak. Four bidirectional effects were observed; in each case a majority of subjects preferred the sure outcome under a positive frame but the gamble under a negative frame. In contrast, a unidirectional framing effect refers to a preference shift due to the framing of choice outcomes: A majority of subjects preferred one choice outcome (either the sure thing or the gamble) under both framing conditions, with positive frame augmented the preference for the sure thing and negative frame augmented the preference for the gamble. These findings revealed some dynamic regularities of framing effects and posed implications for developing predictive and testable

  2. The cysteines of the extracellular loop are crucial for trafficking of human organic cation transporter 2 to the plasma membrane and are involved in oligomerization.

    Science.gov (United States)

    Brast, Sabine; Grabner, Alexander; Sucic, Sonja; Sitte, Harald H; Hermann, Edwin; Pavenstädt, Hermann; Schlatter, Eberhard; Ciarimboli, Giuliano

    2012-03-01

    Human organic cation transporter 2 (hOCT2) is involved in transport of many endogenous and exogenous organic cations, mainly in kidney and brain cells. Because the quaternary structure of transmembrane proteins plays an essential role for their cellular trafficking and function, we investigated whether hOCT2 forms oligomeric complexes, and if so, which part of the transporter is involved in the oligomerization. A yeast 2-hybrid mating-based split-ubiquitin system (mbSUS), fluorescence resonance energy transfer, Western blot analysis, cross-linking experiments, immunofluorescence, and uptake measurements of the fluorescent organic cation 4-(4-(dimethylamino)styryl)-N-methylpyridinium were applied to human embryonic kidney 293 (HEK293) cells transfected with hOCT2 and partly also to freshly isolated human proximal tubules. The role of cysteines for oligomerization and trafficking of the transporter to the plasma membranes was investigated in cysteine mutants of hOCT2. hOCT2 formed oligomers both in the HEK293 expression system and in native human kidneys. The cysteines of the large extracellular loop are important to enable correct folding, oligomeric assembly, and plasma membrane insertion of hOCT2. Mutation of the first and the last cysteines of the loop at positions 51 and 143 abolished oligomer formation. Thus, the cysteines of the extracellular loop are important for correct trafficking of the transporter to the plasma membrane and for its oligomerization.

  3. Structure of Pseudoknot PK26 Shows 3D Domain Swapping in an RNA

    Science.gov (United States)

    Lietzke, Susan E; Barnes, Cindy L.

    1998-01-01

    3D domain swapping provides a facile pathway for the evolution of oligomeric proteins and allosteric mechanisms and a means for using monomer-oligomer equilibria to regulate biological activity. The term "3D domain swapping" describes the exchange of identical domains between two protein monomers to create an oligomer. 3D domain swapping has, so far, only been recognized in proteins. In this study, the structure of the pseudoknot PK26 is reported and it is a clear example of 3D domain swapping in RNA. PK26 was chosen for study because RNA pseudoknots are required structures in several biological processes and they arise frequently in in vitro selection experiments directed against protein targets. PK26 specifically inhibits HIV-1 reverse transcriptase with nanomolar affinity. We have now determined the 3.1 A resolution crystal structure of PK26 and find that it forms a 3D domain swapped dimer. PK26 shows extensive base pairing between and within strands. Formation of the dimer requires the linker region between the pseudoknot folds to adopt a unique conformation that allows a base within a helical stem to skip one base in the stacking register. Rearrangement of the linker would permit a monomeric pseudoknot to form. This structure shows how RNA can use 3D domain swapping to build large scale oligomers like the putative hexamer in the packaging RNA of bacteriophage Phi29.

  4. Synthesis and characterization of polyhedral oligomeric titanized silsesquioxane: A new biocompatible cage like molecule for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Yahyaei, Hossein [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Mohseni, Mohsen, E-mail: mmohseni@aut.ac.ir [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Ghanbari, Hossein [Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Messori, Massimo [Dipartimento di Ingegneria ‘Enzo Ferrari’, Università di Modena e Reggio Emilia, Modena (Italy)

    2016-04-01

    Organic–inorganic hybrid materials have shown improved properties to be used as biocompatible coating in biomedical applications. Polyhedral oligomeric silsesquioxane (POSS) containing coatings are among hybrid materials showing promising properties for these applications. In this work an open cage POSS has been reacted with a titanium alkoxide to end cap the POSS molecule with titanium atom to obtain a so called polyhedral oligomeric metalized silsesquioxane (POMS). The synthesized POMS was characterized by FTIR, RAMAN and UV–visible spectroscopy as well as {sup 29}Si NMR and matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) techniques. Appearance of peaks at 920 cm{sup −1} in FTIR and 491 cm{sup −1} and 1083 cm{sup −1} in Raman spectra confirmed Si–O–Ti linkage formation. It was also demonstrated that POMS was in a monomeric form. To evaluate the biocompatibility of hybrids films, pristine POSS and synthesized POMS were used in synthesis of a polycarbonate urethane polymer. Results revealed that POMS containing hybrid, not only had notable thermal and mechanical stability compared to POSS containing one, as demonstrated by DSC and DMTA analysis, they also showed controlled surface properties in such a manner that hydrophobicity and biocompatibility were both reachable to give rise to improved cell viability in presence of human umbilical vein endothelial cells (HUVEC) and MRC-5 cells. - Highlight: • Polyhedral Oligomeric Metalized Silsesquioxane (POMS) based on titanium was synthesized. • POMS can improve mechanical properties of polyurethane. • POMS increases hydrophobicity of polyurethane. • POMS is a unique nanocage to enhance biocompatibility of polyurethane.

  5. MxiN Differentially Regulates Monomeric and Oligomeric Species of the Shigella Type Three Secretion System ATPase Spa47.

    Science.gov (United States)

    Case, Heather B; Dickenson, Nicholas E

    2018-04-17

    Shigella rely entirely on the action of a single type three secretion system (T3SS) to support cellular invasion of colonic epithelial cells and to circumvent host immune responses. The ATPase Spa47 resides at the base of the Shigella needle-like type three secretion apparatus (T3SA), supporting protein secretion through the apparatus and providing a likely means for native virulence regulation by Shigella and a much needed target for non-antibiotic therapeutics to treat Shigella infections. Here, we show that MxiN is a differential regulator of Spa47 and that its regulatory impact is determined by the oligomeric state of the Spa47 ATPase, with which it interacts. In vitro and in vivo characterization shows that interaction of MxiN with Spa47 requires the six N-terminal residues of Spa47 that are also necessary for stable Spa47 oligomer formation and activation. This interaction with MxiN negatively influences the activity of Spa47 oligomers while upregulating the ATPase activity of monomeric Spa47. Detailed kinetic analyses of monomeric and oligomeric Spa47 in the presence and absence of MxiN uncover additional mechanistic insights into the regulation of Spa47 by MxiN, suggesting that the MxiN/Spa47 species resulting from interaction with monomeric and oligomeric Spa47 are functionally distinct and that both could be involved in Shigella T3SS regulation. Uncovering regulation of Spa47 by MxiN addresses an important gap in the current understanding of how Shigella controls T3SA activity and provides the first description of differential T3SS ATPase regulation by a native T3SS protein.

  6. METHAPHYSICS OF DEATH PENALTY

    Directory of Open Access Journals (Sweden)

    V. E. Gromov

    2017-06-01

    Full Text Available Purpose. The paper studies the problem of death penalty justifiableness in terms of democratic society from the metaphysical viewpoint. Philosophical argumentation to justify death penalty is proposed as opposed to the common idea of inhuman and uncivilized nature of court practice of sentencing to death. The essence of the study is not to rehabilitate law-based murder but to explain dialectic relation of the degrees of moral responsibility of criminals and society nourishing evildoers. The author believes that refusal from death penalty under the pretence of rule of humanism is just a liberal façade, plausible excuse for defective moral state of the society which, rejecting its own guiltiness share as for current disregards of the law, does not grow but downgrades proper human dignity. Methodology. The author applies an approach of dialectic reflection being guided by the perception of unity, relativeness and complementarity of evil and good striving to determine efficient way of resolving their contradictions in the context of moral progress of the society. Originality. Proposing philosophic approach to a death penalty problem instead of legal one, the author is not going to discuss the role of horrification, control or cruelty of the measure of restraint; moreover, he does not consider the issue of its efficiency or inefficiency. The author also does not concern vexation of mind of a criminal sentenced to life imprisonment for “humanitarian” reasons. The purpose of the author is to demonstrate that aim of the punishment is to achieve justice which becomes spiritual challenge and moral recompense not only for the criminal but for the whole society. Conclusions. Crime is first of all a problem of a society; thus, criminal behaviour of certain individuals should only be considered through a prism of moral state of the whole community. Attitude to a death penalty is the problem of spirituality and its dramatic sophistication. The author

  7. In situ oligomerization of 2-(thiophen-3-yl)acetate intercalated into Zn{sub 2}Al layered double hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Tronto, Jairo, E-mail: jairotronto@ufv.br [Universidade Federal de Viçosa, Instituto de Ciências Exatas e Tecnológicas, Campus de Rio Parsanaíba, Rodovia BR 354 km 310, Cx. Postal 22, CEP, 38.810-000 Rio Paranaíba, MG (Brazil); Pinto, Frederico G.; Costa, Liovando M. da [Universidade Federal de Viçosa, Instituto de Ciências Exatas e Tecnológicas, Campus de Rio Parsanaíba, Rodovia BR 354 km 310, Cx. Postal 22, CEP, 38.810-000 Rio Paranaíba, MG (Brazil); Leroux, Fabrice; Dubois, Marc [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, BP 80026, F-6317 Clermont-Ferrand (France); Valim, João B. [Universidade de São Paulo, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Departamento de Química, Av. dos Bandeirantes 3900, CEP 14.040-901, Ribeirão Preto, SP (Brazil)

    2015-01-15

    A layered double hydroxide (LDH) with cation composition Zn{sub 2}Al was intercalated with 2-(thiophen-3-yl)acetate (3-TA) monomers. To achieve in situ polymerization and/or oligomerization of the intercalated monomers, soft thermal treatments were carried out, and subsequent hybrid LDH materials were analyzed by means of several characterization techniques using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), {sup 13}C CP–MAS nuclear magnetic resonance (NMR), electron spin resonance (EPR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP–OES), and elemental analysis. PXRD analysis suggested that the intercalated monomers formed a bilayer. Thermal treatment of the hybrid LDH assembly above 120 °C provokes partially the breakdown of the layered structure, generating the phase zincite. EPR results indicated that vicinal monomers (oligomerization) were bound to each other after hydrothermal or thermal treatment, leading to a polaron response characteristic of electron conductivity localized on a restricted number of thiophene-based monomer segments. Localized unpaired electrons exist in the material and interact with the {sup 27}Al nuclei of the LDH layers by superhyperfine coupling. These unpaired electrons also interact with the surface of ZnO (O{sup 2−} vacancies), formed during the thermal treatments. - Graphical abstract: We synthesized a layered double hydroxide (LDH) with cation composition Zn{sub 2}Al, intercalated with 2-(thiophen-3-yl)acetate (3-TA) monomers, by coprecipitation at constant pH. We thermally treated the material, to achieve in situ polymerization and/or oligomerization of the intercalated monomers. - Highlights: • A Zn{sub 2}Al–LDH was intercalated with 2-(thiophen-3-yl)acetate monomers. • To achieve in situ oligomerization of the monomers, thermal treatments were made.

  8. A New Star-shaped Carbazole Derivative with Polyhedral Oligomeric Silsesquioxane Core: Crystal Structure and Unique Photoluminescence Property.

    Science.gov (United States)

    Xu, Zixuan; Yu, Tianzhi; Zhao, Yuling; Zhang, Hui; Zhao, Guoyun; Li, Jianfeng; Chai, Lanqin

    2016-01-01

    A new inorganic–organic hybrid material based on polyhedral oligomeric silsesquioxane (POSS) capped with carbazolyl substituents, octakis[3-(carbazol-9-yl)propyldimethylsiloxy]-silsesquioxane (POSS-8Cz), was successfully synthesized and characterized. The X-ray crystal structure of POSS-8Cz were described. The photophysical properties of POSS-8Cz were investigated by using UV–vis,photoluminescence spectroscopic analysis. The hybrid material exhibits blue emission in the solution and the solid film.The morphology and thermal stablity properties were measured by X-ray diffraction (XRD) and TG-DTA analysis.

  9. Oligomerization of adenosin-5´-O-ylmethylphosphonate, an isopolar AMP analogue: Evaluation of the route to short oligoadenylates

    Czech Academy of Sciences Publication Activity Database

    Pressová, Martina; Buděšínský, Miloš; Kóšiová, Ivana; Kopecký, V. Jr.; Cvačka, Josef; Kašička, Václav; Šimák, Ondřej; Točík, Zdeněk; Rosenberg, Ivan

    2010-01-01

    Roč. 93, č. 3 (2010), s. 277-289 ISSN 0006-3525 R&D Projects: GA MŠk(CZ) LC06077; GA MŠk(CZ) LC06061; GA AV ČR KAN200520801; GA ČR GA203/09/0820; GA ČR GA202/09/0193 Grant - others:EMIL-FW6(XE) 503569 Institutional research plan: CEZ:AV0Z40550506 Keywords : spontaneous oligomerization * oligoadenylates * phosphonate linkage Subject RIV: CC - Organic Chemistry Impact factor: 2.572, year: 2010

  10. Rotavirus NSP4 is secreted from infected cells as an oligomeric lipoprotein and binds to glycosaminoglycans on the surface of non-infected cells

    Directory of Open Access Journals (Sweden)

    Didsbury Alicia

    2011-12-01

    Full Text Available Abstract Background Nonstructural glycoprotein 4 (NSP4 encoded by rotavirus is the only viral protein currently believed to function as an enterotoxin. NSP4 is synthesized as an intracellular transmembrane glycoprotein and as such is essential for virus assembly. Infection of polarized Caco-2 cells with rotavirus also results in the secretion of glycosylated NSP4 apparently in a soluble form despite retention of its transmembrane domain. We have examined the structure, solubility and cell-binding properties of this secreted form of NSP4 to further understand the biochemical basis for its enterotoxic function. We show here that NSP4 is secreted as discrete detergent-sensitive oligomers in a complex with phospholipids and demonstrate that this secreted form of NSP4 can bind to glycosaminoglycans present on the surface of a range of different cell types. Methods NSP4 was purified from the medium of infected cells after ultracentrifugation and ultrafiltration by successive lectin-affinity and ion exchange chromatography. Oligomerisation of NSP4 was examined by density gradient centrifugation and chemical crosslinking and the lipid content was assessed by analytical thin layer chromatography and flame ionization detection. Binding of NSP4 to various cell lines was measured using a flow cytometric-based assay. Results Secreted NSP4 formed oligomers that contained phospholipid but dissociated to a dimeric species in the presence of non-ionic detergent. The purified glycoprotein binds to the surface of various non-infected cells of distinct lineage. Binding of NSP4 to HT-29, a cell line of intestinal origin, is saturable and independent of divalent cations. Complementary biochemical approaches reveal that NSP4 binds to sulfated glycosaminoglycans on the plasma membrane. Conclusion Our study is the first to analyze an authentic (i.e. non-recombinant form of NSP4 that is secreted from virus-infected cells. Despite retention of the transmembrane domain

  11. Death from Nitrous Oxide.

    Science.gov (United States)

    Bäckström, Björn; Johansson, Bengt; Eriksson, Anders

    2015-11-01

    Nitrous oxide is an inflammable gas that gives no smell or taste. It has a history of abuse as long as its clinical use, and deaths, although rare, have been reported. We describe two cases of accidental deaths related to voluntary inhalation of nitrous oxide, both found dead with a gas mask covering the face. In an attempt to find an explanation to why the victims did not react properly to oncoming hypoxia, we performed experiments where a test person was allowed to breath in a closed system, with or without nitrous oxide added. Vital signs and gas concentrations as well as subjective symptoms were recorded. The experiments indicated that the explanation to the fact that neither of the descendents had reacted to oncoming hypoxia and hypercapnia was due to the inhalation of nitrous oxide. This study raises the question whether nitrous oxide really should be easily, commercially available. © 2015 American Academy of Forensic Sciences.

  12. [Karoshi, death by overwork].

    Science.gov (United States)

    Uehata, Tetsunojo

    2005-07-01

    Karoshi (death by overwork) is one of social medical terms, which used by survivors of victims who attacked with cardiovascular diseases such as stroke, myocardial infarction and sudden cardiac death. In Dec. 2000, Compensation Standard of cardiovascular diseases in Workers' Insurance was changed and admitted the relationship between chronic fatigue and cardiovascular attacks. As a result, compensation numbers of Karoshi attributed to three hundred and more from about 80 cases. The Ministry of Health, Labour and Welfare thinks that most of Karoshi caused by long working hours continuing for several months, especially without payment, so that the Labour Standard Inspector Office requests to decrease overtime work more than 45 hours per month to firm administrators.

  13. AN AUDIT OF MATERNAL DEATHS

    Directory of Open Access Journals (Sweden)

    Basavana Gowda

    2015-03-01

    Full Text Available OBJECTIVES: A study of maternal death conducted to evaluate various factors responsible for maternal deaths. To identify complications in pregnancy, a childbirth which result in maternal death, and to identify opportunities for preventive intervention and understand the events leading to death; so that improving maternal health and reducing maternal mortality rate significantly. To analyze the causes and epidemiological amounts maternal mortality e.g. age parity, socioeconomic status and literacy. In order to reduce maternal mortality and to implement safe motherhood program and complications of pregnancy and to find out safe motherhood program. METHODS: The data collected was a retrograde by a proforma containing particulars of the diseased, detailed history and relatives were interviewed for additional information. The data collected was analysed. RESULTS: Maternal mortality rate in our own institution is 200/ 100,000 live births. Among 30 maternal deaths, 56% deaths (17 were among low socio - economic status, groups 60% deaths among unbooked 53.5% deaths more along illiterates evidenced by direct and indirect deaths about 25% of deaths were preventable. CONCLUSION: Maternal death is a great tragedy in the family life. It is crusade to know not just the medical cause of the death but the circumstances what makes these continued tragic death even more unacceptable is that deaths are largely preventable

  14. MRI of 'brain death'

    International Nuclear Information System (INIS)

    Nishino, Shigeki; Itoh, Takahiko; Tuchida, Shohei; Kinugasa, Kazushi; Asari, Shoji; Nishimoto, Akira; Sanou, Kazuo.

    1990-01-01

    Magnetic resonance imaging (MRI) was undertaken for two patients who suffered from severe cerebrovascular diseases and were clinically brain dead. The MRI system we used was Resona (Yokogawa Medical Systems, superconductive system 0.5 T) and the CT apparatus was Toshiba TCT-300. Initial CT and MRI were undertaken as soon as possible after admission, and repeated sequentially. After diagnosis of brain death, we performed angiography to determine cerebral circulatory arrest, and MRI obtained at the same time was compared with the angiogram and CT. Case 1 was a 77-year-old man who was admitted in an unconscious state. CT and MRI on the second day after hospitalization revealed cerebellar infarction. He was diagnosed as brain dead on day 4. Case 2 was a 35-year-old man. When he was transferred to our hospital, he was in cardiorespiratory arrested. Cardiac resuscitation was successful but no spontaneous respiration appeared. CT and MRI on admission revealed right intracerebral hemorrhage. Angiography revealed cessation of contrast medium in intracranial vessels in both of the patients. We found no 'flow signal void sign' in the bilateral internal carotid and basilar arteries on MRI images in both cases after brain death. MRI, showing us the anatomical changes of the brain, clearly revealed brain herniations, even though only nuclear findings of 'brain tamponade' were seen on CT. But in Case 1, we could not see the infarct lesions in the cerebellum on MR images obtained after brain death. This phenomenon was caused by the whole brain ischemia masking the initial ischemic lesions. We concluded that MRI was useful not only the anatomical display of lesions and brain herniation with high contrast resolution but for obtaining information on cerebral circulation of brain death. (author)

  15. [Sudden death from hypoglycemia].

    Science.gov (United States)

    Asmundo, A; Aragona, M; Gualniera, P; Aragona, F

    1995-12-01

    The sudden death by hypoglycemia is an aspect of the forensic pathology frequently neglected. Authors initially described the pathogenesis of different hypoglycemia forms, distinguishing the primary ones due to hyperinsulinism and the secondary ones due to functional insufficiency of other organs (hypophysis, thyroid, adrenal gland, liver); after that Authors described three cases of sudden death induced hypoglycemia by hyperinsulinism: two were unweaned with nesidioblastosis and one adolescent. In any form of hypoglycemia the central nervous system damage is present with evident neuronal degenerative-necrotic phenomena, widespread edema with microhemorrhage, swollen and dissociation of myelin sheath, glial cells hyperplasia. Death caused by primary hypoglycemia is histopathologically different from the secondary one because of the maintenance of hepatic glycogen content in the former, that increase in striated muscles, including the heart, in spite of the constant secretion of catecholamine from the adrenal medulla. Glycogen is depleted in secondary hypoglycemia. In the primary form, behind the adrenal medulla hyperfunction, the increased functional activity of the adrenal cortex is moderate, contrasting with the seriousness of the syndrome, due prevalently to inhibit the gluconeogenesis response conditioned by the persistence of stored glycogen in the liver, heart and striated muscles. The rare anoxic processes coming with resynthesis of hepatic glycogen have to be considered in the differential diagnosis. The primary hypoglycemic death, especially in unweaned, is frequently promoted by other processes inducing hypoxia (fetal asphyxia outcome, pneumonia, etc.) or worsening the hypoglycemia (hypothyroidism, etc.). The secondary hypoglycemias are characterized by the normality of exocrine pancreas and by organic alterations that cause glycogen depletion from the liver.

  16. Fear of death.

    Science.gov (United States)

    Penson, Richard T; Partridge, Rosamund A; Shah, Muhammad A; Giansiracusa, David; Chabner, Bruce A; Lynch, Thomas J

    2005-02-01

    Shortly before his death in 1995, Kenneth B. Schwartz, a cancer patient at Massachusetts General Hospital (MGH) founded The Kenneth B. Schwartz Center at MGH. The Schwartz Center is a nonprofit organization dedicated to supporting and advancing compassionate health care delivery, which provides hope to the patient and support to caregivers and encourages the healing process. The center sponsors the Schwartz Center Rounds, a monthly multidisciplinary forum where caregivers reflect on important psychosocial issues faced by patients, their families, and their caregivers, and gain insight and support from fellow staff members. For many, cancer is synonymous with death. Fearing death is a rational response. For too long, medicine has ignored this primeval fear. Increasingly, clinicians recognize and address end-of-life issues, facing patients' and our own emotional vulnerabilities in order to connect and explore problems and fears. Listening and learning from the patient guides us as we acknowledge much of the mystery that still surrounds the dying process. Rarely is there a simple or right answer. An empathetic response to suffering patients is the best support. Support is vital in fostering the adjustment of patients. A silent presence may prove more helpful than well-meant counsel for many patients. Through an examination of eight caregiver narratives of their patients' experiences, the role of the health care provider in the dying process, particularly in regard to challenging fear, is reviewed.

  17. Predicting success of oligomerized pool engineering (OPEN for zinc finger target site sequences

    Directory of Open Access Journals (Sweden)

    Goodwin Mathew J

    2010-11-01

    Full Text Available Abstract Background Precise and efficient methods for gene targeting are critical for detailed functional analysis of genomes and regulatory networks and for potentially improving the efficacy and safety of gene therapies. Oligomerized Pool ENgineering (OPEN is a recently developed method for engineering C2H2 zinc finger proteins (ZFPs designed to bind specific DNA sequences with high affinity and specificity in vivo. Because generation of ZFPs using OPEN requires considerable effort, a computational method for identifying the sites in any given gene that are most likely to be successfully targeted by this method is desirable. Results Analysis of the base composition of experimentally validated ZFP target sites identified important constraints on the DNA sequence space that can be effectively targeted using OPEN. Using alternate encodings to represent ZFP target sites, we implemented Naïve Bayes and Support Vector Machine classifiers capable of distinguishing "active" targets, i.e., ZFP binding sites that can be targeted with a high rate of success, from those that are "inactive" or poor targets for ZFPs generated using current OPEN technologies. When evaluated using leave-one-out cross-validation on a dataset of 135 experimentally validated ZFP target sites, the best Naïve Bayes classifier, designated ZiFOpT, achieved overall accuracy of 87% and specificity+ of 90%, with an ROC AUC of 0.89. When challenged with a completely independent test set of 140 newly validated ZFP target sites, ZiFOpT performance was comparable in terms of overall accuracy (88% and specificity+ (92%, but with reduced ROC AUC (0.77. Users can rank potentially active ZFP target sites using a confidence score derived from the posterior probability returned by ZiFOpT. Conclusion ZiFOpT, a machine learning classifier trained to identify DNA sequences amenable for targeting by OPEN-generated zinc finger arrays, can guide users to target sites that are most likely to function

  18. A Death in the Family: Death as a Zen Concept

    Science.gov (United States)

    Black, Helen K.; Rubinstein, Robert L.

    2013-01-01

    This study is based on original research that explored family reaction to the death of an elderly husband and father. We interviewed 34 families (a family included a widow and two adult biological children) approximately 6 to 10 months after the death. In one-on-one interviews, we discussed family members' initial reaction to the death, how the…

  19. Supersymmetric domain walls

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Kleinschmidt, Axel; Riccioni, Fabio

    2012-01-01

    We classify the half-supersymmetric "domain walls," i.e., branes of codimension one, in toroidally compactified IIA/IIB string theory and show to which gauged supergravity theory each of these domain walls belong. We use as input the requirement of supersymmetric Wess-Zumino terms, the properties of

  20. Protective Effects of Testosterone on Presynaptic Terminals against Oligomeric β-Amyloid Peptide in Primary Culture of Hippocampal Neurons

    Directory of Open Access Journals (Sweden)

    Chi-Fai Lau

    2014-01-01

    Full Text Available Increasing lines of evidence support that testosterone may have neuroprotective effects. While observational studies reported an association between higher bioavailable testosterone or brain testosterone levels and reduced risk of Alzheimer’s disease (AD, there is limited understanding of the underlying neuroprotective mechanisms. Previous studies demonstrated that testosterone could alleviate neurotoxicity induced by β-amyloid (Aβ, but these findings mainly focused on neuronal apoptosis. Since synaptic dysfunction and degeneration are early events during the pathogenesis of AD, we aim to investigate the effects of testosterone on oligomeric Aβ-induced synaptic changes. Our data suggested that exposure of primary cultured hippocampal neurons to oligomeric Aβ could reduce the length of neurites and decrease the expression of presynaptic proteins including synaptophysin, synaptotagmin, and synapsin-1. Aβ also disrupted synaptic vesicle recycling and protein folding machinery. Testosterone preserved the integrity of neurites and the expression of presynaptic proteins. It also attenuated Aβ-induced impairment of synaptic exocytosis. By using letrozole as an aromatase antagonist, we further demonstrated that the effects of testosterone on exocytosis were unlikely to be mediated through the estrogen receptor pathway. Furthermore, we showed that testosterone could attenuate Aβ-induced reduction of HSP70, which suggests a novel mechanism that links testosterone and its protective function on Aβ-induced synaptic damage. Taken together, our data provide further evidence on the beneficial effects of testosterone, which may be useful for future drug development for AD.

  1. Nanomolar oligomerization and selective co-aggregation of α-synuclein pathogenic mutants revealed by single-molecule fluorescence

    Science.gov (United States)

    Sierecki, Emma; Giles, Nichole; Bowden, Quill; Polinkovsky, Mark E.; Steinbeck, Janina; Arrioti, Nicholas; Rahman, Diya; Bhumkar, Akshay; Nicovich, Philip R.; Ross, Ian; Parton, Robert G.; Böcking, Till; Gambin, Yann

    2016-01-01

    Protein aggregation is a hallmark of many neurodegenerative diseases, notably Alzheimer’s and Parkinson’s disease. Parkinson’s disease is characterized by the presence of Lewy bodies, abnormal aggregates mainly composed of α-synuclein. Moreover, cases of familial Parkinson’s disease have been linked to mutations in α-synuclein. In this study, we compared the behavior of wild-type (WT) α-synuclein and five of its pathological mutants (A30P, E46K, H50Q, G51D and A53T). To this end, single-molecule fluorescence detection was coupled to cell-free protein expression to measure precisely the oligomerization of proteins without purification, denaturation or labelling steps. In these conditions, we could detect the formation of oligomeric and pre-fibrillar species at very short time scale and low micromolar concentrations. The pathogenic mutants surprisingly segregated into two classes: one group forming large aggregates and fibrils while the other tending to form mostly oligomers. Strikingly, co-expression experiments reveal that members from the different groups do not generally interact with each other, both at the fibril and monomer levels. Together, this data paints a completely different picture of α-synuclein aggregation, with two possible pathways leading to the development of fibrils. PMID:27892477

  2. Fingolimod phosphate attenuates oligomeric amyloid β-induced neurotoxicity via increased brain-derived neurotrophic factor expression in neurons.

    Directory of Open Access Journals (Sweden)

    Yukiko Doi

    Full Text Available The neurodegenerative processes that underlie Alzheimer's disease are mediated, in part, by soluble oligomeric amyloid β, a neurotoxic protein that inhibits hippocampal long-term potentiation, disrupts synaptic plasticity, and induces the production of reactive oxygen species. Here we show that the sphingosine-1-phosphate (S1P receptor (S1PR agonist fingolimod phosphate (FTY720-P-a new oral drug for multiple sclerosis-protects neurons against oligomeric amyloid β-induced neurotoxicity. We confirmed that primary mouse cortical neurons express all of the S1P receptor subtypes and FTY720-P directly affects the neurons. Treatment with FTY720-P enhanced the expression of brain-derived neurotrophic factor (BDNF in neurons. Moreover, blocking BDNF-TrkB signaling with a BDNF scavenger, TrkB inhibitor, or ERK1/2 inhibitor almost completely ablated these neuroprotective effects. These results suggested that the neuroprotective effects of FTY720-P are mediated by upregulated neuronal BDNF levels. Therefore, FTY720-P may be a promising therapeutic agent for neurodegenerative diseases, such as Alzheimer's disease.

  3. On social death: ostracism and the accessibility of death thoughts.

    Science.gov (United States)

    Steele, Caroline; Kidd, David C; Castano, Emanuele

    2015-01-01

    Being rejected, excluded, or simply ignored is a painful experience. Ostracism researchers have shown its powerful negative consequences (Williams, 2007), and sociologists have referred to such experiences as social death (Bauman, 1992). Is this is just a metaphor or does being ostracized make death more salient in people's minds? An experiment was conducted in which participants experienced ostracism or inclusion using the Cyberball manipulation, and the accessibility of death-related thoughts was measured via a word-stem completion puzzle. Results showed enhanced death-thought accessibility in the ostracism condition, as well as a negative effect of dispositional self-esteem on the accessibility of death-related thoughts.

  4. Random mutagenesis of the nucleotide-binding domain of NRC1 (NB-LRR Required for Hypersensitive Response-Associated Cell Death-1), a downstream signalling nucleotide-binding, leucine-rich repeat (NB-LRR) protein, identifies gain-of-function mutations in the nucleotide-binding pocket

    NARCIS (Netherlands)

    Sueldo, D.J.; Shimels, M.Z.; Spiridon, L.N.; Caldararu, O.; Petrescu, A.J.; Joosten, M.H.A.J.; Tameling, W.I.L.

    2015-01-01

    •Plant nucleotide-binding, leucine-rich repeat (NB-LRR) proteins confer immunity to pathogens possessing the corresponding avirulence proteins. Activation of NB-LRR proteins is often associated with induction of the hypersensitive response (HR), a form of programmed cell death. •NRC1 (NB-LRR

  5. RIPPED TO DEATH

    OpenAIRE

    Weinlich, Ricardo; Dillon, Christopher P; Green, Douglas R

    2011-01-01

    An old puzzle in the field of cell death was recently solved: the mysterious embryonic lethality of animals deficient either in caspase-8 or FADD, proteins involved in a pathway of apoptosis. This lethality is caused by a failure to develop the yolk sac vasculature rather than a lack of apoptosis. Remarkably, development is rescued by ablation of either of two Receptor Interacting Protein Kinases (RIPKs). Despite being well-known cell killers, caspase-8 and FADD act together to block RIPK-med...

  6. Hypokalemia and sudden cardiac death

    DEFF Research Database (Denmark)

    Kjeldsen, Keld

    2010-01-01

    Worldwide, approximately three million people suffer sudden cardiac death annually. These deaths often emerge from a complex interplay of substrates and triggers. Disturbed potassium homeostasis among heart cells is an example of such a trigger. Thus, hypokalemia and, also, more transient...... of fatal arrhythmia and sudden cardiac death a patient is, the more attention should be given to the potassium homeostasis....

  7. Structure and function of the TIR domain from the grape NLR protein RPV1

    Directory of Open Access Journals (Sweden)

    Simon John Williams

    2016-12-01

    Full Text Available The N-terminal Toll/interleukin-1 receptor/resistance protein (TIR domain has been shown to be both necessary and sufficient for defence signalling in the model plants flax and Arabidopsis. In examples from these organisms, TIR domain self-association is required for signalling function, albeit through distinct interfaces. Here, we investigate these properties in the TIR domain containing resistance protein RPV1 from the wild grapevine Muscadinia rotundifolia. The RPV1 TIR domain, without additional flanking sequence present, is autoactive when transiently expressed in tobacco, demonstrating that the TIR domain alone is capable of cell-death signalling. We determined the crystal structure of the RPV1 TIR domain at 2.3 Å resolution. In the crystals, the RPV1 TIR domain forms a dimer, mediated predominantly through residues in the αA and αE helices (AE interface. This interface is shared with the interface discovered in the dimeric complex of the TIR domains from the Arabidopsis RPS4/RRS1 resistance protein pair. We show that surface-exposed residues in the AE interface that mediate the dimer interaction in the crystals are highly conserved among plant TIR domain-containing proteins. While we were unable to demonstrate self-association of the RPV1 TIR domain in solution or using yeast 2-hybrid, mutations of surface-exposed residues in the AE interface prevent the cell-death autoactive phenotype. In addition, mutation of residues known to be important in the cell-death signalling function of the flax L6 TIR domain were also shown to be required for RPV1 TIR domain mediated cell-death. Our data demonstrate that multiple TIR domain surfaces control the cell-death function of the RPV1 TIR domain and we suggest that the conserved AE interface may have a general function in TIR-NLR signalling.

  8. Evidence for allosteric effects on p53 oligomerization induced by phosphorylation

    Czech Academy of Sciences Publication Activity Database

    Muller, P.; Chan, J.M.; Šimončík, O.; Fojta, Miroslav; Lane, D.P.; Hupp, T.; Vojtěšek, B.

    2018-01-01

    Roč. 27, č. 2 (2018), s. 523-530 ISSN 0961-8368 R&D Projects: GA ČR GBP206/12/G151 Institutional support: RVO:68081707 Keywords : protein -kinase ck2 * tumor-suppressor protein * dna-binding domain Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 2.523, year: 2016

  9. Mind Bomb Regulates Cell Death during TNF Signaling by Suppressing RIPK1’s Cytotoxic Potential

    Directory of Open Access Journals (Sweden)

    Rebecca Feltham

    2018-04-01

    Full Text Available Summary: Tumor necrosis factor (TNF is an inflammatory cytokine that can signal cell survival or cell death. The mechanisms that switch between these distinct outcomes remain poorly defined. Here, we show that the E3 ubiquitin ligase Mind Bomb-2 (MIB2 regulates TNF-induced cell death by inactivating RIPK1 via inhibitory ubiquitylation. Although depletion of MIB2 has little effect on NF-κB activation, it sensitizes cells to RIPK1- and caspase-8-dependent cell death. We find that MIB2 represses the cytotoxic potential of RIPK1 by ubiquitylating lysine residues in the C-terminal portion of RIPK1. Our data suggest that ubiquitin conjugation of RIPK1 interferes with RIPK1 oligomerization and RIPK1-FADD association. Disruption of MIB2-mediated ubiquitylation, either by mutation of MIB2’s E3 activity or RIPK1’s ubiquitin-acceptor lysines, sensitizes cells to RIPK1-mediated cell death. Together, our findings demonstrate that Mind Bomb E3 ubiquitin ligases can function as additional checkpoint of cytokine-induced cell death, selectively protecting cells from the cytotoxic effects of TNF. : Feltham et al. show that MIB2 directly ubiquitylates RIPK1 upon TNF stimulation, suppressing the cytotoxic potential of RIPK1 and acting as a checkpoint within the TNF signaling pathway. Keywords: MIB2, RIPK1, TNF, cell death, caspase-8, IAPs, ubiquitin

  10. Expression, purification, crystallization and preliminary X-ray studies of the Ebola VP35 interferon inhibitory domain

    International Nuclear Information System (INIS)

    Leung, Daisy W.; Ginder, Nathaniel D.; Nix, Jay C.; Basler, Christopher F.; Honzatko, Richard B.; Amarasinghe, Gaya K.

    2009-01-01

    Native and selenomethionine-labeled crystals of Ebola VP35 interferon inhibitory domain were obtained by the hanging-drop vapor-diffusion method. Ebola VP35 is a multifunctional protein that is important for host immune suppression and pathogenesis. VP35 contains an N-terminal oligomerization domain and a C-terminal interferon inhibitory domain (IID). Mutations within the VP35 IID result in loss of host immune suppression. Here, efforts to crystallize recombinantly overexpressed VP35 IID that was purified from Escherichia coli are described. Native and selenomethionine-labeled crystals belonging to the orthorhombic space group P2 1 2 1 2 1 were obtained by the hanging-drop vapor-diffusion method and diffraction data were collected at the ALS synchrotron

  11. Solution structure of the N-terminal domain of a replication restart primosome factor, PriC, in Escherichia coli

    Science.gov (United States)

    Aramaki, Takahiko; Abe, Yoshito; Katayama, Tsutomu; Ueda, Tadashi

    2013-01-01

    In eubacterial organisms, the oriC-independent primosome plays an essential role in replication restart after the dissociation of the replication DNA-protein complex by DNA damage. PriC is a key protein component in the replication restart primosome. Our recent study suggested that PriC is divided into two domains: an N-terminal and a C-terminal domain. In the present study, we determined the solution structure of the N-terminal domain, whose structure and function have remained unknown until now. The revealed structure was composed of three helices and one extended loop. We also observed chemical shift changes in the heteronuclear NMR spectrum and oligomerization in the presence of ssDNA. These abilities may contribute to the PriC-ssDNA complex, which is important for the replication restart primosome. PMID:23868391

  12. Conformational analysis of isolated domains of Helicobacter pylori CagA.

    Directory of Open Access Journals (Sweden)

    Amanda P Woon

    Full Text Available The CagA protein of Helicobacter pylori is associated with increased virulence and gastric cancer risk. CagA is translocated into the host cell by a H. pylori type IV secretion system via mechanisms that are poorly understood. Translocated CagA interacts with numerous host factors, altering a variety of host signalling pathways. The recently determined crystal structure of C-terminally-truncated CagA indicated the presence of two domains: the smaller, flexible N-terminal domain and the larger, middle domain. In this study, we have investigated the conformation, oligomeric state and stability of the N-terminal, middle and glutamate-proline-isoleucine-tyrosine-alanine (EPIYA-repeats domains. All three domains are monomeric, suggesting that the multimerisation of CagA observed in infected cells is likely to be mediated not by CagA itself but by its interacting partners. The middle and the C-terminal domains, but not the N-terminal domain, are capable of refolding spontaneously upon heat denaturation, lending support to the hypothesis that unfolded CagA is threaded C-terminus first through the type IV secretion channel with its N-terminal domain, which likely requires interactions with other domains to refold, being threaded last. Our findings also revealed that the C-terminal EPIYA-repeats domain of CagA exists in an intrinsically disordered premolten globule state with regions in PPII conformation--a feature that is shared by many scaffold proteins that bind multiple protein components of signalling pathways. Taken together, these results provide a deeper understanding of the physicochemical properties of CagA that underpin its complex cellular and oncogenic functions.

  13. Toll-like receptor 2 and nucleotide-binding oligomerization domain-2 play divergent roles in the recognition of gut-derived lactobacilli and bifidobacteria in dendritic cells

    DEFF Research Database (Denmark)

    Zeuthen, Louise; Fink, Lisbeth Nielsen; Frøkiær, Hanne

    2008-01-01

    -marrow-derived DC lacking NOD2 produce higher levels of interleukin-10 (IL-10) and reduced levels of IL-12 and tumour necrosis factor-[alpha] (TNF-[alpha]) in response to LAB. This indicates that peptidoglycan is partly responsible for the T helper type 1 skewing effect of certain LAB. Dendritic cells that are TLR2......-[alpha]-inducing bifidobacteria inhibit the T helper type 1 skewing effect induced by strong immunostimulatory lactobacilli. Here we show that this immunoinhibitory effect of bifidobacteria is dependent on TLR2 and independent of NOD2. Moreover, independently of the cytokine pattern induced by intact LAB, cell wall fractions...

  14. Western Scientific Approaches to Near-Death Experiences

    Directory of Open Access Journals (Sweden)

    Bruce Greyson

    2015-11-01

    Full Text Available Near-death experiences (NDEs are vivid experiences that often occur in life-threatening conditions, usually characterized by a transcendent tone and clear perceptions of leaving the body and being in a different spatiotemporal dimension. Such experiences have been reported throughout history in diverse cultures, and are reported today by 10% to 20% of people who have come close to death. Although cultural expectations and parameters of the brush with death influence the content of some NDEs, near-death phenomenology is invariant across cultures. That invariance may reflect universal psychological defenses, neurophysiological processes, or actual experience of a transcendent or mystical domain. Research into these alternative explanations has been hampered by the unpredictable occurrence of NDEs. Regardless of the causes or interpretations of NDEs, however, they are consistently associated with profound and long-lasting aftereffects on experiencers, and may have important implications for non-experiencers as well.

  15. Brain Death in Islamic Jurisprudence

    Directory of Open Access Journals (Sweden)

    A Nikzad

    2016-07-01

    Full Text Available BACKGROUND AND OBJECTIVE: In today's world, Islamic jurisprudence encounters  new issues. One of the areas where jurisprudence gets involved is the issues concerned with brain death, whether brain death in jurisprudence and Islamic law is considered the end of life. In this study, brain death was discussed from the Shiite jurisprudence perspective and also the opinions of the specialists are taken into account. METHODS: This study is designed based on library collection and review of the literature in the field of brain death. Also, Quranic verses, hadiths and fatwas (religious opinions of the scholars are used. Some of the articles which were centered around Islamic jurisprudence, particularly Shiite jurisprudence that explain and deal with brain death were given special consideration. FINDINGS: Brain death from religious and jurisprudence perspective is considered the termination of life and removing the vital organs from the body is not viewed as committing manslaughter. A person with brain death is not a normally known injured man who is still alive. The brain death patinets have no life and getting rid of the body does not constitute a case of manslaughter. Amputation of the organs of brain death patients for donation and transplantation amounts to the amputation of a dead body. If the life of a Muslim is subject to transplant of organs from the body of a brain death patient, it will be permissible. CONCLUSION: In principle, if the life of a Muslim entails transplant of organs of brain death patients, it will be permissible 

  16. Conserved Domain Database (CDD)

    Data.gov (United States)

    U.S. Department of Health & Human Services — CDD is a protein annotation resource that consists of a collection of well-annotated multiple sequence alignment models for ancient domains and full-length proteins.

  17. Optimal Aging and Death

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Strulik, Holger

    2010-01-01

    health investments. At the same time, physiological aspects of the aging process influence optimal savings and health investment. We calibrate the model for the average US male in 2000 and proceed to show that the calibrated model accounts well for the cross-country link between labor productivity......This study introduces physiological aging into a simple model of optimal intertemporal consumption. In this endeavor we draw on the natural science literature on aging. According to the purposed theory, the speed of the aging process and the time of death are endogenously determined by optimal...... and life expectancy in the same year ("the Preston curve"); cross-country income differences can explain differences in life expectancy at age 20 of up to a decade. Moreover, technological change in health care of about 1.1% per year can account for the observed shift in the Preston curve between 1980...

  18. Organ donations after death

    Directory of Open Access Journals (Sweden)

    Bernarda Logar

    2003-09-01

    Full Text Available The paper discusses public opinion on post-mortem organ donation, especially the difference between high support of public opinion to transplant activity, its general readiness to donate organs and the low number of signed organ donor cards. Through different approaches the article tries to point out possible factors relevant to the decision to donate organs. Early studies showed demographic variables and information as significant factors when deciding to donate organs after death. As there was not enough evidence that long-term effect through these factors is significant, the need for new investigation has grown. Social cognition theories helped understanding the difference mentioned above. It seems that the use of this approach might contribute to the understanding the problem and to delimit most useful factors when working with public.

  19. Constitutive homo- and hetero-oligomerization of TbetaRII-B, an alternatively spliced variant of the mouse TGF-beta type II receptor

    DEFF Research Database (Denmark)

    Krishnaveni, Manda S; Hansen, Jakob Lerche; Seeger, Werner

    2006-01-01

    , but the oligomerization pattern and dynamics of TbetaRII splice variants in live cells has not been demonstrated thus far. Using co-immunoprecipitation and bioluminescence resonance energy transfer (BRET), we demonstrate that the mouse TbetaRII receptor splice variant TbetaRII-B is capable of forming ligand...

  20. Iron-induced oligomerization of human FXN81-210 and bacterial CyaY frataxin and the effect of iron chelators

    DEFF Research Database (Denmark)

    Ahlgren, Eva Christina; Fekry, Mostafa; Wiemann, Mathias

    2017-01-01

    long forms, FXN42-210 and FXN56-210, have been shown to spontaneously form oligomeric particles stabilized by the extended N-terminal sequence. The short variant FXN81-210, on other hand, has only been observed in the monomeric state. However, a highly homologous E. coli frataxin CyaY, which also lacks...

  1. Oligomeric forms of the metastasis-related Mts1 (S100A4) protein stimulate neuronal differentiation in cultures of rat hippocampal neurons

    DEFF Research Database (Denmark)

    Novitskaya, V; Grigorian, M; Kriajevska, M

    2000-01-01

    protein family. The oligomeric but not the dimeric form of Mts1 strongly induces differentiation of cultured hippocampal neurons. A mutant with a single Y75F amino acid substitution, which stabilizes the dimeric form of Mts1, is unable to promote neurite extension. Disulfide bonds do not play an essential...

  2. The CoxD protein, a novel AAA+ ATPase involved in metal cluster assembly: hydrolysis of nucleotide-triphosphates and oligomerization.

    Directory of Open Access Journals (Sweden)

    Tobias Maisel

    Full Text Available CoxD of the α-proteobacterium Oligotropha carboxidovorans is a membrane protein which is involved in the posttranslational biosynthesis of the [CuSMoO₂] cluster in the active site of the enzyme CO dehydrogenase. The bacteria synthesize CoxD only in the presence of CO. Recombinant CoxD produced in E. coli K38 pGP1-2/pETMW2 appeared in inclusion bodies from where it was solubilized by urea and refolded by stepwise dilution. Circular dichroism spectroscopy revealed the presence of secondary structural elements in refolded CoxD. CoxD is a P-loop ATPase of the AAA-protein family. Refolded CoxD catalyzed the hydrolysis of MgATP yielding MgADP and inorganic phosphate at a 1∶1∶1 molar ratio. The reaction was inhibited by the slow hydrolysable MgATP-γ-S. GTPase activity of CoxD did not exceed 2% of the ATPase activity. Employing different methods (non linear regression, Hanes and Woolf, Lineweaver-Burk, preparations of CoxD revealed a mean K(M value of 0.69±0.14 mM ATP and an apparent V(max value of 19.3±2.3 nmol ATP hydrolyzed min⁻¹ mg⁻¹. Sucrose density gradient centrifugation and gel filtration showed that refolded CoxD can exist in various multimeric states (2-mer, 4-mer or 6-mer, preferentially as hexamer or dimer. Within weeks the hexamer dissociates into the dimer, a process which can be reversed by MgATP or MgATP-γ-S within hours. Only the hexamers and the dimers exhibited MgATPase activity. Transmission electron microscopy of negatively stained CoxD preparations revealed distinct particles within a size range of 10-16 nm, which further corroborates the oligomeric organization. The 3D structure of CoxD was modeled with the 3D structure of BchI from Rhodobacter capsulatus as template. It has the key elements of an AAA+ domain in the same arrangement and at same positions as in BchI and displays the characteristic inserts of the PS-II-insert clade. Possible functions of CoxD in [CuSMoO₂] cluster assembly are discussed.

  3. A cytosolic juxtamembrane interface modulates plexin A3 oligomerization and signal transduction.

    Directory of Open Access Journals (Sweden)

    Rachael Barton

    Full Text Available Plexins (plxns are transmembrane (TM receptors involved in the guidance of vascular, lymphatic vessel, and neuron growth as well as cancer metastasis. Plxn signaling results in cytosolic GTPase-activating protein activity, and previous research implicates dimerization as important for activation of plxn signaling. Purified, soluble plxn extracellular and cytosolic domains exhibit only weak homomeric interactions, suggesting a role for the plxn TM and juxtamembrane regions in homooligomerization. In this study, we consider a heptad repeat in the Danio rerio PlxnA3 cytosolic juxtamembrane domain (JM for its ability to influence PlxnA3 homooligomerization in TM-domain containing constructs. Site-directed mutagenesis in conjunction with the AraTM assay and bioluminescent energy transfer (BRET² suggest an interface involving a JM heptad repeat, in particular residue M1281, regulates PlxnA3 homomeric interactions when examined in constructs containing an ectodomain, TM and JM domain. In the presence of a neuropilin-2a co-receptor and semaphorin 3F ligand, disruption to PlxnA3 homodimerization caused by an M1281F mutation is eliminated, suggesting destabilization of the PlxnA3 homodimer in the JM is not sufficient to disrupt co-receptor complex formation. In contrast, enhanced homodimerization of PlxnA3 caused by mutation M1281L remains even in the presence of ligand semaphorin 3F and co-receptor neuropilin-2a. Consistent with this pattern of PlxnA3 dimerization in the presence of ligand and co-receptor, destabilizing mutations to PlxnA3 homodimerization (M1281F are able to rescue motor patterning defects in sidetracked zebrafish embryos, whereas mutations that enhance PlxnA3 homodimerization (M1281L are not. Collectively, our results indicate the JM heptad repeat, in particular residue M1281, forms a switchable interface that modulates both PlxnA3 homomeric interactions and signal transduction.

  4. The MARVEL transmembrane motif of occludin mediates oligomerization and targeting to the basolateral surface in epithelia.

    Science.gov (United States)

    Yaffe, Yakey; Shepshelovitch, Jeanne; Nevo-Yassaf, Inbar; Yeheskel, Adva; Shmerling, Hedva; Kwiatek, Joanna M; Gaus, Katharina; Pasmanik-Chor, Metsada; Hirschberg, Koret

    2012-08-01

    Occludin (Ocln), a MARVEL-motif-containing protein, is found in all tight junctions. MARVEL motifs are comprised of four transmembrane helices associated with the localization to or formation of diverse membrane subdomains by interacting with the proximal lipid environment. The functions of the Ocln MARVEL motif are unknown. Bioinformatics sequence- and structure-based analyses demonstrated that the MARVEL domain of Ocln family proteins has distinct evolutionarily conserved sequence features that are consistent with its basolateral membrane localization. Live-cell microscopy, fluorescence resonance energy transfer (FRET) and bimolecular fluorescence complementation (BiFC) were used to analyze the intracellular distribution and self-association of fluorescent-protein-tagged full-length human Ocln or the Ocln MARVEL motif excluding the cytosolic C- and N-termini (amino acids 60-269, FP-MARVEL-Ocln). FP-MARVEL-Ocln efficiently arrived at the plasma membrane (PM) and was sorted to the basolateral PM in filter-grown polarized MDCK cells. A series of conserved aromatic amino acids within the MARVEL domain were found to be associated with Ocln dimerization using BiFC. FP-MARVEL-Ocln inhibited membrane pore growth during Triton-X-100-induced solubilization and was shown to increase the membrane-ordered state using Laurdan, a lipid dye. These data demonstrate that the Ocln MARVEL domain mediates self-association and correct sorting to the basolateral membrane.

  5. Deaths: Leading Causes for 2012.

    Science.gov (United States)

    Heron, Melonie

    2015-08-31

    This report presents final 2012 data on the 10 leading causes of death in the United States by age, sex, race, and Hispanic origin. Leading causes of infant, neonatal, and postneonatal death are also presented. This report supplements "Deaths: Final Data for 2012," the National Center for Health Statistics' annual report of final mortality statistics. Data in this report are based on information from all death certificates filed in the 50 states and the District of Columbia in 2012. Causes of death classified by the International Classification of Diseases, Tenth Revision (ICD-10) are ranked according to the number of deaths assigned to rankable causes. Cause-of-death statistics are based on the underlying cause of death. In 2012, the 10 leading causes of death were, in rank order: Diseases of heart; Malignant neoplasms; Chronic lower respiratory diseases; Cerebrovascular diseases; Accidents (unintentional injuries); Alzheimer's disease; Diabetes mellitus; Influenza and pneumonia; Nephritis, nephrotic syndrome and nephrosis; and Intentional self-harm (suicide). These causes accounted for 74% of all deaths occurring in the United States. Differences in the rankings are evident by age, sex, race, and Hispanic origin. Leading causes of infant death for 2012 were, in rank order: Congenital malformations, deformations and chromosomal abnormalities; Disorders related to short gestation and low birth weight, not elsewhere classified; Sudden infant death syndrome; Newborn affected by maternal complications of pregnancy; Accidents (unintentional injuries); Newborn affected by complications of placenta, cord and membranes; Bacterial sepsis of newborn; Respiratory distress of newborn; Diseases of the circulatory system; and Neonatal hemorrhage. Important variations in the leading causes of infant death are noted for the neonatal and postneonatal periods.

  6. 3DSwap: Curated knowledgebase of proteins involved in 3D domain swapping

    KAUST Repository

    Shameer, Khader

    2011-09-29

    Three-dimensional domain swapping is a unique protein structural phenomenon where two or more protein chains in a protein oligomer share a common structural segment between individual chains. This phenomenon is observed in an array of protein structures in oligomeric conformation. Protein structures in swapped conformations perform diverse functional roles and are also associated with deposition diseases in humans. We have performed in-depth literature curation and structural bioinformatics analyses to develop an integrated knowledgebase of proteins involved in 3D domain swapping. The hallmark of 3D domain swapping is the presence of distinct structural segments such as the hinge and swapped regions. We have curated the literature to delineate the boundaries of these regions. In addition, we have defined several new concepts like \\'secondary major interface\\' to represent the interface properties arising as a result of 3D domain swapping, and a new quantitative measure for the \\'extent of swapping\\' in structures. The catalog of proteins reported in 3DSwap knowledgebase has been generated using an integrated structural bioinformatics workflow of database searches, literature curation, by structure visualization and sequence-structure-function analyses. The current version of the 3DSwap knowledgebase reports 293 protein structures, the analysis of such a compendium of protein structures will further the understanding molecular factors driving 3D domain swapping. The Author(s) 2011.

  7. DFT study on the impact of the methylaluminoxane cocatalyst in ethylene oligomerization using a titanium-based catalyst

    KAUST Repository

    Pasha, Farhan Ahmad

    2015-01-26

    A computational study within the framework of density functional theory is presented on the oligomerization of ethylene to yield 1-hexene using [(η5-C5H4CMe2C6H5)]TiCl3/MAO] catalyst. This study explicitly takes into account a methylaluminoxane (MAO) cocatalyst model, where the MAO cluster has become an anionic species after having abstracted one chloride anion, yielding a cationic activated catalyst. Hence, the reaction profile was calculated using the zwitterionic system, and the potential energy surface has been compared to the cationic catalytic system. Modest differences were found between the two free energy profiles. However, we show for the first time that the use of a realistic zwitterionic model is required to obtain a Brønsted-Evans-Polanyi relationship between the energy barriers and reaction energies.

  8. DFT study on the impact of the methylaluminoxane cocatalyst in ethylene oligomerization using a titanium-based catalyst

    KAUST Repository

    Pasha, Farhan Ahmad; Basset, Jean-Marie; Toulhoat, Hervé ; De Bruin, Theodorus J M

    2015-01-01

    A computational study within the framework of density functional theory is presented on the oligomerization of ethylene to yield 1-hexene using [(η5-C5H4CMe2C6H5)]TiCl3/MAO] catalyst. This study explicitly takes into account a methylaluminoxane (MAO) cocatalyst model, where the MAO cluster has become an anionic species after having abstracted one chloride anion, yielding a cationic activated catalyst. Hence, the reaction profile was calculated using the zwitterionic system, and the potential energy surface has been compared to the cationic catalytic system. Modest differences were found between the two free energy profiles. However, we show for the first time that the use of a realistic zwitterionic model is required to obtain a Brønsted-Evans-Polanyi relationship between the energy barriers and reaction energies.

  9. Effects of Bentonite on p-Methoxybenzyl Acetate: A Theoretical Model for Oligomerization via an Electrophilic-Substitution Mechanism

    Directory of Open Access Journals (Sweden)

    Manuel Salmón

    2011-02-01

    Full Text Available Tonsil Actisil FF, a commercial bentonitic clay, promotes the formation of a series of electrophilic-aromatic-substitution products from para-methoxybenzyl acetate in carbon disulfide. The molecules obtained correspond to linear isomeric dimers, trimers, tetramers and a pentamer, according to their spectroscopic data. A clear indication of the title mechanistic pathway for the oligomerization growth was obtained from the analysis of a set of computational-chemistry calculations using the density-functional-theory level B3LYP/6-311++G(d,p. The corresponding conclusions were based on the computed dipole moments, the HOMO/LUMO distributions, and a natural-populations analysis of the studied molecules.

  10. Multiwalled carbon nanotubes@octavinyl polyhedral oligomeric silsesquioxanes nanocomposite preparation via cross-linking reaction in acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Somasekharan, Lakshmipriya; Thomas, Sabu [Mahatma Gandhi University, International and Interuniversity Centre for Nanoscience and Nanotechnology (India); Comoy, Corinne [Université de Lorraine, SRSMC, UMR 7565 (France); Sivasankarapillai, Anilkumar [NSS Hindu College (India); Kalarikkal, Nandakumar [Mahatma Gandhi University, International and Interuniversity Centre for Nanoscience and Nanotechnology (India); Lamouroux, Emmanuel, E-mail: Emmanuel.Lamouroux@univ-lorraine.fr [Université de Lorraine, SRSMC, UMR 7565 (France)

    2016-11-15

    Multiwalled carbon nanotubes have unique properties allowing their use in a wide range of applications—from microelectronics to biomedical and polymer fields. Nevertheless, a crucial aspect for their use resides in the ease of handling them during the process. Here, we report a facile route to prepare multiwalled carbon nanotubes@octavinyl polyhedral oligomeric silsesquioxanes (MWCNT@POSS) nanocomposite. The method involves the formation of a covalent bond between carboxylated MWCNTs and OV-POSS using acid-catalyzed electrophilic addition reaction. The resulting nanocomposite have been characterized by Fourier transform infrared spectroscopy (FTIR), powder X-Ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The results confirmed that the formation of MWCNT@POSS nanocomposite did not deteriorate MWCNT structure or morphology. Here, we used a 1:1 ratio of carboxylated MWCNTs and OV-POSS and the POSS content in the nanocomposite was 39.5 wt%.

  11. Cartilage oligomeric matrix protein deficiency promotes early onset and the chronic development of collagen-induced arthritis

    DEFF Research Database (Denmark)

    Geng, Hui; Carlsen, Stefan; Nandakumar, Kutty

    2008-01-01

    ABSTRACT: INTRODUCTION: Cartilage oligomeric matrix protein (COMP) is a homopentameric protein in cartilage. The development of arthritis, like collagen-induced arthritis (CIA), involves cartilage as a target tissue. We have investigated the development of CIA in COMP-deficient mice. METHODS: COMP......-deficient mice in the 129/Sv background were backcrossed for 10 generations against B10.Q mice, which are susceptible to chronic CIA. COMP-deficient and wild-type mice were tested for onset, incidence, and severity of arthritis in both the collagen and collagen antibody-induced arthritis models. Serum anti......-collagen II and anti-COMP antibodies as well as serum COMP levels in arthritic and wild-type mice were measured by enzyme-linked immunosorbent assay. RESULTS: COMP-deficient mice showed a significant early onset and increase in the severity of CIA in the chronic phase, whereas collagen II-antibody titers were...

  12. Structural Insights into the Unusually Strong ATPase Activity of the AAA Domain of the Caenorhabditis elegans Fidgetin-like 1 (FIGL-1) Protein*

    Science.gov (United States)

    Peng, Wentao; Lin, Zhijie; Li, Weirong; Lu, Jing; Shen, Yuequan; Wang, Chunguang

    2013-01-01

    The FIGL-1 (fidgetin like-1) protein is a homolog of fidgetin, a protein whose mutation leads to multiple developmental defects. The FIGL-1 protein contains an AAA (ATPase associated with various activities) domain and belongs to the AAA superfamily. However, the biological functions and developmental implications of this protein remain unknown. Here, we show that the AAA domain of the Caenorhabditis elegans FIGL-1 protein (CeFIGL-1-AAA), in clear contrast to homologous AAA domains, has an unusually high ATPase activity and forms a hexamer in solution. By determining the crystal structure of CeFIGL-1-AAA, we found that the loop linking helices α9 and α10 folds into the short helix α9a, which has an acidic surface and interacts with a positively charged surface of the neighboring subunit. Disruption of this charge interaction by mutagenesis diminishes both the ATPase activity and oligomerization capacity of the protein. Interestingly, the acidic residues in helix α9a of CeFIGL-1-AAA are not conserved in other homologous AAA domains that have relatively low ATPase activities. These results demonstrate that the sequence of CeFIGL-1-AAA has adapted to establish an intersubunit charge interaction, which contributes to its strong oligomerization and ATPase activity. These unique properties of CeFIGL-1-AAA distinguish it from other homologous proteins, suggesting that CeFIGL-1 may have a distinct biological function. PMID:23979136

  13. Structural insights into the unusually strong ATPase activity of the AAA domain of the Caenorhabditis elegans fidgetin-like 1 (FIGL-1) protein.

    Science.gov (United States)

    Peng, Wentao; Lin, Zhijie; Li, Weirong; Lu, Jing; Shen, Yuequan; Wang, Chunguang

    2013-10-11

    The FIGL-1 (fidgetin like-1) protein is a homolog of fidgetin, a protein whose mutation leads to multiple developmental defects. The FIGL-1 protein contains an AAA (ATPase associated with various activities) domain and belongs to the AAA superfamily. However, the biological functions and developmental implications of this protein remain unknown. Here, we show that the AAA domain of the Caenorhabditis elegans FIGL-1 protein (CeFIGL-1-AAA), in clear contrast to homologous AAA domains, has an unusually high ATPase activity and forms a hexamer in solution. By determining the crystal structure of CeFIGL-1-AAA, we found that the loop linking helices α9 and α10 folds into the short helix α9a, which has an acidic surface and interacts with a positively charged surface of the neighboring subunit. Disruption of this charge interaction by mutagenesis diminishes both the ATPase activity and oligomerization capacity of the protein. Interestingly, the acidic residues in helix α9a of CeFIGL-1-AAA are not conserved in other homologous AAA domains that have relatively low ATPase activities. These results demonstrate that the sequence of CeFIGL-1-AAA has adapted to establish an intersubunit charge interaction, which contributes to its strong oligomerization and ATPase activity. These unique properties of CeFIGL-1-AAA distinguish it from other homologous proteins, suggesting that CeFIGL-1 may have a distinct biological function.

  14. Substitution of proline32 by α-methylproline preorganizes β2-microglobulin for oligomerization but not for aggregation into amyloids.

    Science.gov (United States)

    Torbeev, Vladimir; Ebert, Marc-Olivier; Dolenc, Jozica; Hilvert, Donald

    2015-02-25

    Conversion of soluble folded proteins into insoluble amyloids generally proceeds in three distinct mechanistic stages: (1) initial protein misfolding into aggregation-competent conformers, (2) subsequent formation of oligomeric species and, finally, (3) self-assembly into extended amyloid fibrils. In the work reported herein, we interrogated the amyloidogenesis mechanism of human β2-microglobulin (β2m), which is thought to be triggered by a pivotal cis-trans isomerization of a proline residue at position 32 in the polypeptide, with nonstandard amino acids. Using chemical protein synthesis we prepared a β2m analogue in which Pro32 was replaced by the conformationally constrained amino acid α-methylproline (MePro). The strong propensity of MePro to adopt a trans prolyl bond led to enhanced population of a non-native [trans-MePro32]β2m protein conformer, which readily formed oligomers at neutral pH. In the presence of the antibiotic rifamycin SV, which inhibits amyloid growth of wild-type β2m, [MePro32]β2m was nearly quantitatively converted into different spherical oligomeric species. Self-assembly into amyloid fibrils was not observed in the absence of seeding, however, even at low pH (<3), where wild-type β2m spontaneously forms amyloids. Nevertheless, we found that aggregation-preorganized [MePro32]β2m can act in a prion-like fashion, templating misfolded conformations in a natively folded protein. Overall, these results provide detailed insight into the role of cis-trans isomerization of Pro32 and ensuing structural rearrangements that lead to initial β2m misfolding and aggregation. They corroborate the view that conformational protein dynamics enabled by reversible Pro32 cis-trans interconversion rather than simple population of the trans conformer is critical for both nucleation and subsequent growth of β2m amyloid structures.

  15. Assessment of Escherichia coli selenophosphate synthetase oligomeric states by analytical ultracentrifugation and small angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Silva, I.R.; Faim, F.M.; Oliveira Neto, M.; Thiemann, O.H. [Universidade de Sao Paulo (USP-SC), Sao Carlos, SP (Brazil); Borges, J.C. [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica

    2012-07-01

    Full text: Selenium is an essential micronutrient for many organisms and is present in selenium-containing proteins as selenocysteine (Sec) and RNAs as selenouridine. Specific selenium incorporation into selenoproteins and RNAs requires the generation of a biologically active selenium donor compound, selenophosphate, which is produced from the activation of selenide with adenosine 5-triphosphate (ATP) in a reaction catalyzed by Selenophosphate Synthetase (SELD). Therefore, SELD is a key enzyme of the selenium pathway in the cell. The Escherichia coli SELD open reading frame was cloned into pET28a (Novagen) expression vector and the recombinant protein was over expressed in Escherichia coli BL21(DE3) strain. In order to purify the protein, we used metal-chelate affinity chromatography followed by a gel filtration step. Analytical Ultracentrifugation (AUC) and Small Angle X-ray Scattering (SAXS) were employed to study the oligomeric states of the soluble protein. The results of AUC revealed dimer-tetramer and tetramer-octamer equilibrium at low concentrations of protein, with dissociation constants of 70 2 and 560 40 M, respectively. Moreover, the SAXS results pointed the oligomeric state of the protein at higher concentrations as predominantly dimeric and the p(r) and the SAXS envelope revealed the SELD as elongated. We also performed initial crystallization trials with protein samples at 7 mg/ml in 96-well sitting-drop crystallization plates at room temperature using a crystallization robot. Needle crystals appeared after some days. X-ray diffraction for these crystals were tested in the MX2 beamline at the Brazilian Synchrotron Laboratory (LNLS Campinas). We are now working to improve these crystals in order to obtain suitable crystals for structure determination. (author)

  16. Structural basis for TatA oligomerization: an NMR study of Escherichia coli TatA dimeric structure.

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    Full Text Available Many proteins are transported across lipid membranes by protein translocation systems in living cells. The twin-arginine transport (Tat system identified in bacteria and plant chloroplasts is a unique system that transports proteins across membranes in their fully-folded states. Up to date, the detailed molecular mechanism of this process remains largely unclear. The Escherichia coli Tat system consists of three essential transmembrane proteins: TatA, TatB and TatC. Among them, TatB and TatC form a tight complex and function in substrate recognition. The major component TatA contains a single transmembrane helix followed by an amphipathic helix, and is suggested to form the translocation pore via self-oligomerization. Since the TatA oligomer has to accommodate substrate proteins of various sizes and shapes, the process of its assembly stands essential for understanding the translocation mechanism. A structure model of TatA oligomer was recently proposed based on NMR and EPR observations, revealing contacts between the transmembrane helices from adjacent subunits. Herein we report the construction and stabilization of a dimeric TatA, as well as the structure determination by solution NMR spectroscopy. In addition to more extensive inter-subunit contacts between the transmembrane helices, we were also able to observe interactions between neighbouring amphipathic helices. The side-by-side packing of the amphipathic helices extends the solvent-exposed hydrophilic surface of the protein, which might be favourable for interactions with substrate proteins. The dimeric TatA structure offers more detailed information of TatA oligomeric interface and provides new insights on Tat translocation mechanism.

  17. Parental divorce and parental death

    DEFF Research Database (Denmark)

    Marcussen, Jette; Thuen, Frode; Poul, Bruun

    2015-01-01

    The aim of this review was to identify research on children and adolescents who experience double bereavement, i.e. the experience of loss through parental divorce followed by either parental death or critical illness with imminent death. This knowledge may identify evidence to underpin knowledge......; challenges in both custodial and non-custodial parental death; risk of mental health problems, and the need of support and interventions....

  18. On an aggregation in birth-and-death stochastic dynamics

    Science.gov (United States)

    Finkelshtein, Dmitri; Kondratiev, Yuri; Kutoviy, Oleksandr; Zhizhina, Elena

    2014-06-01

    We consider birth-and-death stochastic dynamics of particle systems with attractive interaction. The heuristic generator of the dynamics has a constant birth rate and density-dependent decreasing death rate. The corresponding statistical dynamics is constructed. Using the Vlasov-type scaling we derive the limiting mesoscopic evolution and prove that this evolution propagates chaos. We study a nonlinear non-local kinetic equation for the first correlation function (density of population). The existence of uniformly bounded solutions as well as solutions growing inside of a bounded domain and expanding in the space are shown. These solutions describe two regimes in the mesoscopic system: regulation and aggregation.

  19. On an aggregation in birth-and-death stochastic dynamics

    International Nuclear Information System (INIS)

    Finkelshtein, Dmitri; Kondratiev, Yuri; Kutoviy, Oleksandr; Zhizhina, Elena

    2014-01-01

    We consider birth-and-death stochastic dynamics of particle systems with attractive interaction. The heuristic generator of the dynamics has a constant birth rate and density-dependent decreasing death rate. The corresponding statistical dynamics is constructed. Using the Vlasov-type scaling we derive the limiting mesoscopic evolution and prove that this evolution propagates chaos. We study a nonlinear non-local kinetic equation for the first correlation function (density of population). The existence of uniformly bounded solutions as well as solutions growing inside of a bounded domain and expanding in the space are shown. These solutions describe two regimes in the mesoscopic system: regulation and aggregation. (paper)

  20. Parthanatos, a messenger of death

    OpenAIRE

    David, Karen Kate; Andrabi, Shaida Ahmad; Dawson, Ted Murray; Dawson, Valina Lynn

    2009-01-01

    Poly-ADP-ribose polymerase-1 (PARP-1)'s multiple roles in the cell span from maintaining life to inducing death. The processes PARP-1 is involved in include, but are not limited to DNA repair, DNA transcription, mitosis, and cell death. Of PARP-1's different cellular functions, its active role in cell death is of particular interest to designing therapies for diseases. Genetic deletion of PARP-1 revealed that PARP-1 over activation underlies cell death in experimental models of stroke, diabet...

  1. A "good death": perspectives of Muslim patients and health care providers.

    Science.gov (United States)

    Tayeb, Mohamad A; Al-Zamel, Ersan; Fareed, Muhammed M; Abouellail, Hesham A

    2010-01-01

    Twelve "good death" principles have been identified that apply to Westerners. This study aimed to review the TFHCOP good death perception to determine its validity for Muslim patients and health care providers, and to identify and describe other components of the Muslim good death perspective. Participants included 284 Muslims of both genders with different nationalities and careers. We used a 12-question questionnaire based on the 12 principles of the TFHCOP good death definition, followed by face-to-face interviews. We used descriptive statistics to analyze questionnaire responses. However, for new themes, we used a grounded theory approach with a "constant comparisons" method. On average, each participant agreed on eight principles of the questionnaire. Dignity, privacy, spiritual and emotional support, access to hospice care, ability to issue advance directives, and to have time to say goodbye were the top priorities. Participants identified three main domains. The first domain was related to faith and belief. The second domain included some principles related to self-esteem and person's image to friends and family. The third domain was related to satisfaction about family security after the death of the patient. Professional role distinctions were more pronounced than were gender or nationality differences. Several aspects of "good death," as perceived by Western communities, are not recognized as being important by many Muslim patients and health care providers. Furthermore, our study introduced three novel components of good death in Muslim society.

  2. Sudden death in athletes.

    Science.gov (United States)

    Corrado, Domenico; Zorzi, Alessandro

    2017-06-15

    Competitive sports activity is associated with an increased risk of sudden cardiovascular death (SCD) in adolescents and young adults with clinically silent cardiovascular disorders. While in middle-aged/senior athletes atherosclerotic coronary artery disease accounts for the vast majority of SCDs, in young athletes the spectrum of substrates is wider and includes inherited (cardiomyopathies) and congenital (anomalous origin of coronary arteries) structural heart diseases. Inherited ion channel diseases have been implicated in SCDs occurring with an apparently normal heart at autopsy. Screening including the ECG allows identification of athletes affected by heart muscle diseases at a pre-symptomatic stage and may lead to reduction of the risk of SCD during sports. The use of modern criteria for interpretation of the ECG in the athlete offers the potential to improve the screening accuracy by reducing the number of false positives. Screening with exercise testing middle aged/senior athletes engaged in leisure sports activity is likely to be effective in patients with significant coronary risk factors, while it is not useful in low-risk subgroups. The availability of automated external defibrillator on the athletic field provides a "back-up" preventive strategy for unpredictable arrhythmic cardiac arrest, mostly occurring in patients with coronary artery diseases. Copyright © 2017. Published by Elsevier B.V.

  3. Structure of the JmjC domain-containing protein NO66 complexed with ribosomal protein Rpl8

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chengliang [University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of (China); Chinese Academy of Sciences, Hefei, Anhui 230026, People’s Republic of (China); Zhang, Qiongdi [University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of (China); Hang, Tianrong [University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of (China); Chinese Academy of Sciences, Hefei, Anhui 230026, People’s Republic of (China); Tao, Yue [Shanghai Children’s Medical Center, 1678 Dongfang Road, Pudong, Shanghai 200120, People’s Republic of (China); Ma, Xukai [University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of (China); Wu, Minhao; Zhang, Xuan, E-mail: xuanzbin@ustc.edu.cn; Zang, Jianye, E-mail: xuanzbin@ustc.edu.cn [University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of (China); Chinese Academy of Sciences, Hefei, Anhui 230026, People’s Republic of (China)

    2015-08-28

    The structure of the complex of NO66 and Rpl8 was solved in the native state and NO66 recognizes the consensus motif NHXH . Tetramerization is required for efficient substrate binding and catalysis by NO66. The JmjC domain-containing proteins belong to a large family of oxygenases possessing distinct substrate specificities which are involved in the regulation of different biological processes, such as gene transcription, RNA processing and translation. Nucleolar protein 66 (NO66) is a JmjC domain-containing protein which has been reported to be a histone demethylase and a ribosome protein 8 (Rpl8) hydroxylase. The present biochemical study confirmed the hydroxylase activity of NO66 and showed that oligomerization is required for NO66 to efficiently catalyze the hydroxylation of Rpl8. The structures of NO66{sup 176–C} complexed with Rpl8{sup 204–224} in a tetrameric form and of the mutant protein M2 in a dimeric form were solved. Based on the results of structural and biochemical analyses, the consensus sequence motif NHXH recognized by NO66 was confirmed. Several potential substrates of NO66 were found by a BLAST search according to the consensus sequence motif. When binding to substrate, the relative positions of each subunit in the NO66 tetramer shift. Oligomerization may facilitate the motion of each subunit in the NO66 tetramer and affect the catalytic activity.

  4. Genome-Wide Prediction and Analysis of 3D-Domain Swapped Proteins in the Human Genome from Sequence Information.

    Science.gov (United States)

    Upadhyay, Atul Kumar; Sowdhamini, Ramanathan

    2016-01-01

    3D-domain swapping is one of the mechanisms of protein oligomerization and the proteins exhibiting this phenomenon have many biological functions. These proteins, which undergo domain swapping, have acquired much attention owing to their involvement in human diseases, such as conformational diseases, amyloidosis, serpinopathies, proteionopathies etc. Early realisation of proteins in the whole human genome that retain tendency to domain swap will enable many aspects of disease control management. Predictive models were developed by using machine learning approaches with an average accuracy of 78% (85.6% of sensitivity, 87.5% of specificity and an MCC value of 0.72) to predict putative domain swapping in protein sequences. These models were applied to many complete genomes with special emphasis on the human genome. Nearly 44% of the protein sequences in the human genome were predicted positive for domain swapping. Enrichment analysis was performed on the positively predicted sequences from human genome for their domain distribution, disease association and functional importance based on Gene Ontology (GO). Enrichment analysis was also performed to infer a better understanding of the functional importance of these sequences. Finally, we developed hinge region prediction, in the given putative domain swapped sequence, by using important physicochemical properties of amino acids.

  5. Calmodulin overexpression does not alter Cav1.2 function or oligomerization state.

    Science.gov (United States)

    Findeisen, Felix; Tolia, Alexandra; Arant, Ryan; Kim, Eun Young; Isacoff, Ehud; Minor, Daniel L

    2011-01-01

    Interactions between calmodulin (CaM) and voltage-gated calcium channels (Ca(v)s) are crucial for Ca(v) activity-dependent feedback modulation. We recently reported an X-ray structure that shows two Ca(2+)/CaM molecules bound to the Ca(v)1.2 C terminal tail, one at the PreIQ region and one at the IQ domain. Surprisingly, the asymmetric unit of the crystal showed a dimer in which Ca(2+)/CaM bridged two PreIQ helixes to form a 4:2 Ca(2+)/CaM:Ca(v) C-terminal tail assembly. Contrary to previous proposals based on a similar crystallographic dimer, extensive biochemical analysis together with subunit counting experiments of full-length channels in live cell membranes failed to find evidence for multimers that would be compatible with the 4:2 crossbridged complex. Here, we examine this possibility further. We find that CaM over-expression has no functional effect on Ca(v)1.2 inactivation or on the stoichiometry of full-length Ca(v)1.2. These data provide further support for the monomeric Ca(v)1.2 stoichiometry. Analysis of the electrostatic surfaces of the 2:1 Ca(2+)/CaM:Ca(V) C-terminal tail assembly reveals notable patches of electronegativity. These could influence various forms of channel modulation by interacting with positively charged elements from other intracellular channel domains.

  6. Causes of death in Vanuatu.

    Science.gov (United States)

    Carter, Karen; Tovu, Viran; Langati, Jeffrey Tila; Buttsworth, Michael; Dingley, Lester; Calo, Andy; Harrison, Griffith; Rao, Chalapati; Lopez, Alan D; Taylor, Richard

    2016-01-01

    The population of the Pacific Melanesian country of Vanuatu was 234,000 at the 2009 census. Apart from subsistence activities, economic activity includes tourism and agriculture. Current completeness of vital registration is considered too low to be usable for national statistics; mortality and life expectancy (LE) are derived from indirect demographic estimates from censuses/surveys. Some cause of death (CoD) data are available to provide information on major causes of premature death. Deaths 2001-2007 were coded for cause (ICDv10) for ages 0-59 years from: hospital separations (HS) (n = 636), hospital medical certificates (MC) of death (n = 1,169), and monthly reports from community health facilities (CHF) (n = 1,212). Ill-defined causes were 3 % for hospital deaths and 20 % from CHF. Proportional mortality was calculated by cause (excluding ill-defined) and age group (0-4, 5-14 years), and also by sex for 15-59 years. From total deaths by broad age group and sex from 1999 and 2009 census analyses, community deaths were estimated by deduction of hospital deaths MC. National proportional mortality by cause was estimated by a weighted average of MC and CHF deaths. National estimates indicate main causes of deaths <5 years were: perinatal disorders (45 %) and malaria, diarrhea, and pneumonia (27 %). For 15-59 years, main causes of male deaths were: circulatory disease 27 %, neoplasms 13 %, injury 13 %, liver disease 10 %, infection 10 %, diabetes 7 %, and chronic respiratory disease 7 %; and for females: neoplasms 29 %, circulatory disease 15 %, diabetes 10 %, infection 9 %, and maternal deaths 8 %. Infection included tuberculosis, malaria, and viral hepatitis. Liver disease (including hepatitis and cancer) accounted for 18 % of deaths in adult males and 9 % in females. Non-communicable disease (NCD), including circulatory disease, diabetes, neoplasm, and chronic respiratory disease, accounted for 52 % of premature deaths in adult

  7. Staging Death, Translating Death, Rehearsing Death: A Photographer’s Apprenticeship in Dying

    Directory of Open Access Journals (Sweden)

    Daniela Fargione

    2010-10-01

    Full Text Available The preponderance of death imagery in the mass media and a recent interest of photography in the practice of death suggest the need to reevaluate our approach to death and dying, especially when violence is involved. This essay is a case study of History of Violence, Claudio Cravero's last photographic project. His collection of "portraits" reproduce apparent dead bodies, mostly attacked in their own domestic spheres, but neither the perpetrator of death (a mysterious murderer?, nor the weapon used (an omnipresent knife, should be considered as main focal points of the artist's inquiry. The undoubtful protagonist of these photographs, instead, is the light, that illuminates fear: not of death itself, rather of the obnoxious indifference to it, as the result of generalized death imagery saturation.     The staged apparent death displayed in Cravero's photographs serve both as a memento mori and as a strategy to come to terms with the idea of death. In short, it is an apprentship in dying through a domesticating translation practice. Eventually, Cravero's History of Violence offers a complex reflection on the interplay between each individual story and macrolevel social History, thus providing some hypotheses of where violence and death fit in that odd geometry of time and space that we call life.

  8. [Death is also life].

    Science.gov (United States)

    Belliard, F

    1985-01-01

    A nurse at the Center for Voluntary Pregnancy Interruption and Contraception in Angers, which receives 30 abortion requests each week, describes psychological aspects of nursing care for abortion patients. Abortion patients statistically are most likely to be married women around 27 years old with husbands aged 31 on average and with 2 children. Abortions are done under local anesthesia, so that there is no hiatus between the time "before" and that "after" the procedure. Women speak about their moral and physical suffering; their choice is respected by the staff. Despite the regret or mild depression that may follow an abortion, most women experience the greatest difficulty before the procedure and feel primarily relieved afterwards. Nursing work with abortion patients consists in being open to them and accompanying them for a few hours. The patients' comfort and postabortion morbidity depend largely on the reception and understanding they are given by the staff. After the procedure, the topic of contraception is discussed with the patient. Abortion and contraception cannot be dissociated because fertility regulation involves greater well-being for all members of the family. The abortion center is a place of life in which women and couples take responsibility for their sexuality and begin again. It is important not to impose beliefs or feelings about sexuality on the patient. A training which encouraged reflection on the grand problems of life and death as well as understanding of emotions, sentiments, and reactions would be helpful in gaining self knowledge and in living through events such as abortion. A meeting with a psychiatrist every 3 weeks is arranged for all staff members who desire it in order to maintain their emotional balance and work out troubling situations encountered at work. The work at the abortion center is 1 of listening and gaining the patient's confidence in order to dedramatize the abortion and permit the woman and the couple to elect an

  9. Domain: Labour market

    NARCIS (Netherlands)

    Oude Mulders, J.; Wadensjö, E.; Hasselhorn, H.M.; Apt, W.

    This domain chapter is dedicated to summarize research on the effects of labour market contextual factors on labour market participation of older workers (aged 50+) and identify research gaps. While employment participation and the timing of (early) retirement is often modelled as an individual

  10. Cellulose binding domain proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc; Doi, Roy

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  11. Domain-Specific Multimodeling

    DEFF Research Database (Denmark)

    Hessellund, Anders

    the overall level of abstraction. It does, however, also introduce a new problem of coordinating multiple different languages in a single system. We call this problem the coordination problem. In this thesis, we present the coordination method for domain-specific multimodeling that explicitly targets...

  12. GlycoDomainViewer

    DEFF Research Database (Denmark)

    Joshi, Hiren J; Jørgensen, Anja; Schjoldager, Katrine T

    2018-01-01

    features, which enhances visibility and accessibility of the wealth of glycoproteomic data being generated. The GlycoDomainViewer enables visual exploration of glycoproteomic data, incorporating information from recent N- and O-glycoproteome studies on human and animal cell lines and some organs and body...

  13. Parents bereaved by infant death

    DEFF Research Database (Denmark)

    Christiansen, Dorte M.; Elklit, Ask; Olff, Miranda

    2013-01-01

    stress disorder (PTSD) symptoms and potential correlates in 634 mothers and fathers up to 18 years (M=3.4 years) after the death of their infant. Members of a private national support organization for parents bereaved by infant death were contacted and asked to participate in the study. Participants...

  14. Death Competence: An Ethical Imperative

    Science.gov (United States)

    Gamino, Louis A.; Ritter, R. Hal, Jr.

    2012-01-01

    The authors argued that death competence, defined as specialized skill in tolerating and managing clients' problems related to dying, death, and bereavement, is a necessary prerequisite for ethical practice in grief counseling. A selected review of the literature tracing the underpinnings of this concept reveals how a robust construct of death…

  15. Scintigraphic evaluation of brain death

    International Nuclear Information System (INIS)

    Park, C. H.; Bai, M. S.; Cho, K. K.; Kim, S. J.; Yoon, S. N.; Cho, C. W.

    1997-01-01

    A law recognizing brain death is a life saving legal measure in patients suffering from badly diseased organs such as kidney, liver, heart, and lung. Such law is being discussed for legalization at the Korean National Assembly. There are various criteria used for brain death in western world and brain scintiscan is one of them. However, the scintiscan is not considered in establishing brain death in the draft of the law. The purpose of this report is to spread this technique in nuclear medicine society as well as in other medical societies. We evaluated 7 patients with clinical suspicion of brain death by various causes. The patient's age ranged from 5 to 39 years. We used 5-20mCi 99m Tc-HMPAO (d.1-hexamethyl propylene amine oxime) or ECD (Ethyl Cysteinate Dimer), lipophilic agents that cross BBB (blood brain barrier). A dynamic study followed by static or SPECT (single photon emission tomography) was performed. Interpretive criteria used for brain death were 1) no intracranial circulation 2) no brain uptake. The second criteria is heavily used. Five of 7 patients were scintigraphically brain dead and the remaining 2 had some brain uptake excluding the diagnosis of scintigraphic brain death. In conclusion, cerebral perfusion study using a lipophilic brain tracer offers a noninvasive, rapid, easy, accurate and reliable mean in the diagnosis of brain death. We believe that this modality should be included in the criteria of brain death in the draft of the proposed Korean law

  16. The framing of scientific domains

    DEFF Research Database (Denmark)

    Dam Christensen, Hans

    2014-01-01

    domains, and UNISIST helps understanding this navigation. Design/methodology/approach The UNISIST models are tentatively applied to the domain of art history at three stages, respectively two modern, partially overlapping domains, as well as an outline of an art historical domain anno c1820...

  17. The PH domain of phosphoinositide-dependent kinase-1 exhibits a novel, phospho-regulated monomer-dimer equilibrium with important implications for kinase domain activation: single-molecule and ensemble studies.

    Science.gov (United States)

    Ziemba, Brian P; Pilling, Carissa; Calleja, Véronique; Larijani, Banafshé; Falke, Joseph J

    2013-07-16

    Phosphoinositide-dependent kinase-1 (PDK1) is an essential master kinase recruited to the plasma membrane by the binding of its C-terminal PH domain to the signaling lipid phosphatidylinositol-3,4,5-trisphosphate (PIP3). Membrane binding leads to PDK1 phospho-activation, but despite the central role of PDK1 in signaling and cancer biology, this activation mechanism remains poorly understood. PDK1 has been shown to exist as a dimer in cells, and one crystal structure of its isolated PH domain exhibits a putative dimer interface. It has been proposed that phosphorylation of PH domain residue T513 (or the phospho-mimetic T513E mutation) may regulate a novel PH domain dimer-monomer equilibrium, thereby converting an inactive PDK1 dimer to an active monomer. However, the oligomeric states of the PH domain on the membrane have not yet been determined, nor whether a negative charge at position 513 is sufficient to regulate its oligomeric state. This study investigates the binding of purified wild-type (WT) and T513E PDK1 PH domains to lipid bilayers containing the PIP3 target lipid, using both single-molecule and ensemble measurements. Single-molecule analysis of the brightness of the fluorescent PH domain shows that the PIP3-bound WT PH domain on membranes is predominantly dimeric while the PIP3-bound T513E PH domain is monomeric, demonstrating that negative charge at the T513 position is sufficient to dissociate the PH domain dimer and is thus likely to play a central role in PDK1 monomerization and activation. Single-molecule analysis of two-dimensional (2D) diffusion of PH domain-PIP3 complexes reveals that the dimeric WT PH domain diffuses at the same rate as a single lipid molecule, indicating that only one of its two PIP3 binding sites is occupied and there is little penetration of the protein into the bilayer as observed for other PH domains. The 2D diffusion of T513E PH domain is slower, suggesting the negative charge disrupts local structure in a way that allows

  18. Parthanatos, a messenger of death

    Science.gov (United States)

    David, Karen Kate; Andrabi, Shaida Ahmad; Dawson, Ted Murray; Dawson, Valina Lynn

    2015-01-01

    Poly-ADP-ribose polymerase-1 (PARP-1)'s multiple roles in the cell span from maintaining life to inducing death. The processes PARP-1 is involved in include, but are not limited to DNA repair, DNA transcription, mitosis, and cell death. Of PARP-1's different cellular functions, its active role in cell death is of particular interest to designing therapies for diseases. Genetic deletion of PARP-1 revealed that PARP-1 over activation underlies cell death in experimental models of stroke, diabetes, inflammation and neurodegeneration. Since interfering with PARP-1 mediated cell death will be clinically beneficial, great effort has been invested into designing PARP-1 inhibitors and understanding mechanisms downstream of PARP-1 over activation. PARP-1 overactivation may kill by depleting cellular energy through nicotinamide adenine dinucleotide (NAD+) consumption, and by releasing the cell death effector apoptosis-inducing factor (AIF). Unexpectedly, recent evidence shows that poly-ADP ribose (PAR) polymer itself, and not the consumption of NAD+ is the source of cytotoxicity. Thus, PAR polymer acts as a cell death effector downstream of PARP-1-mediated cell death signaling. We coined the term parthanatos after Thanatos, the personification of death in Greek mythology, to refer to PAR-mediated cell death. In this review, we will summarize the proposed mechanisms by which PARP-1 overactivation kills. We will present evidence for parthanatos, and the questions raised by these recent findings. It is evident that further understanding of parthanatos opens up new avenues for therapy in ameliorating diseases related to PARP-1 over activation. PMID:19273119

  19. Lipid raft involvement in yeast cell growth and death

    Energy Technology Data Exchange (ETDEWEB)

    Mollinedo, Faustino, E-mail: fmollin@usal.es [Instituto de Biología Molecular y Celular del Cáncer, Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas - Universidad de Salamanca, Salamanca (Spain)

    2012-10-10

    The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na{sup +}, K{sup +}, and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  20. Lipid raft involvement in yeast cell growth and death

    International Nuclear Information System (INIS)

    Mollinedo, Faustino

    2012-01-01

    The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na + , K + , and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  1. Identification of a tetramerization domain in the C terminus of the vanilloid receptor.

    Science.gov (United States)

    García-Sanz, Nuria; Fernández-Carvajal, Asia; Morenilla-Palao, Cruz; Planells-Cases, Rosa; Fajardo-Sánchez, Emmanuel; Fernández-Ballester, Gregorio; Ferrer-Montiel, Antonio

    2004-06-09

    TRPV1 (transient receptor potential vanilloid receptor subtype 1) is a member of the TRP channel family gated by vanilloids, protons, and heat. Structurally, TRPV1 appears to be a tetramer formed by the assembly of four identical subunits around a central aqueous pore. The molecular determinants that govern its subunit oligomerization remain elusive. Here, we report the identification of a segment comprising 684Glu-721Arg (referred to as the TRP-like domain) in the C terminus of TRPV1 as an association domain (AD) of the protein. Purified recombinant C terminus of TRPV1 (TRPV1-C) formed discrete and stable multimers in vitro. Yeast two-hybrid and pull-down assays showed that self-association of the TRPV1-C is blocked when segment 684Glu-721Arg is deleted. Biochemical and immunological analysis indicate that removal of the AD from full-length TRPV1 monomers blocks the formation of stable heteromeric assemblies with wild-type TRPV1 subunits. Deletion of the AD in a poreless TRPV1 subunit suppressed its robust dominant-negative phenotype. Together, these findings are consistent with the tenet that the TRP-like domain in TRPV1 is a molecular determinant of the tetramerization of receptor subunits into functional channels. Our observations suggest that the homologous TRP domain in the TRP protein family may function as a general, evolutionary conserved AD involved in subunit multimerization.

  2. MPP1 directly interacts with flotillins in erythrocyte membrane - Possible mechanism of raft domain formation.

    Science.gov (United States)

    Biernatowska, Agnieszka; Augoff, Katarzyna; Podkalicka, Joanna; Tabaczar, Sabina; Gajdzik-Nowak, Weronika; Czogalla, Aleksander; Sikorski, Aleksander F

    2017-11-01

    Flotillins are prominent, oligomeric protein components of erythrocyte (RBC) membrane raft domains and are considered to play an important structural role in lateral organization of the plasma membrane. In our previous work on erythroid membranes and giant plasma membrane vesicles (GPMVs) derived from them we have shown that formation of functional domains (resting state rafts) depends on the presence of membrane palmitoylated protein 1 (MPP1/p55), pointing to its new physiological role. Exploration of the molecular mechanism of MPP1 function in organizing membrane domains described here, through searching for its molecular partners in RBC membrane by using different methods, led to the identification of the raft-marker proteins, flotillin 1 and flotillin 2, as hitherto unreported direct MPP1 binding-partners in the RBC membrane. These proteins are found in high molecular-weight complexes in native RBC membrane and, significantly, their presence was shown to be separate from the well-known protein 4.1-dependent interactions of MPP1 with membrane proteins. Furthermore, FLIM analysis revealed that loss of the endogenous MPP1-flotillins interactions resulted in significant changes in RBC membrane-fluidity, emphasizing the physiological importance of such interactions in vivo. Therefore, our data establish a new perspective on the role of MPP1 in erythroid cells and suggests that direct MPP1-flotillins interactions could be the major driving-force behind the formation of raft domains in RBC. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  3. Death: clinical and forensic anthropological perspectives

    OpenAIRE

    Etty Indriati, Etty Indriati

    2015-01-01

    All biological living beings inevitably die, and the ways to die vary although in essence death is a manifestation of the absence of Oxygen in the brain. After death, biological remains undertake proteolysis and decomposition. The aim of this article is to discuss clinical death, cerebral or medicolegal death, social death, phases of cerebral death, and biological process after death—which is important for forensic medicine and forensic anthropology. How long a person die, if the time elaps...

  4. Brain death and related issues

    International Nuclear Information System (INIS)

    Akhtar, M.; Mushtaq, S.; Jamil, K.; Ahmed, S.

    2003-01-01

    Concerns about the erroneous diagnosis of death and premature burial have been expressed from times immemorial. Patients with brain stem death have absolutely no chance of recovery. Brain death is considered at par with death in most of the countries. General public in most parts of the world shows reluctance to accept this concept due to different social, cultural and religious backgrounds and state of literacy and awareness. The criteria for the diagnosis of brain death have been established which include certain pre-conditions, exclusions and tests of the brain stem function. These criteria are universally accepted. The criteria in children are somewhat different from the adults. The subject is intimately related with organ transplantation. If the patients is registered as organ donor or the family consents, organs can be harvested from brain dead patients for transplantation. Pakistan is amongst the few countries where no legislation exists to accept brain death as being at par with death of an individual, and to facilitate and regulate, cadaveric organ donation and transplantation. (author)

  5. Monomeric, Oligomeric and Polymeric Proteins in Huntington Disease and Other Diseases of Polyglutamine Expansion

    Directory of Open Access Journals (Sweden)

    Guylaine Hoffner

    2014-03-01

    Full Text Available Huntington disease and other diseases of polyglutamine expansion are each caused by a different protein bearing an excessively long polyglutamine sequence and are associated with neuronal death. Although these diseases affect largely different brain regions, they all share a number of characteristics, and, therefore, are likely to possess a common mechanism. In all of the diseases, the causative protein is proteolyzed, becomes abnormally folded and accumulates in oligomers and larger aggregates. The aggregated and possibly the monomeric expanded polyglutamine are likely to play a critical role in the pathogenesis and there is increasing evidence that the secondary structure of the protein influences its toxicity. We describe here, with special attention to huntingtin, the mechanisms of polyglutamine aggregation and the modulation of aggregation by the sequences flanking the polyglutamine. We give a comprehensive picture of the characteristics of monomeric and aggregated polyglutamine, including morphology, composition, seeding ability, secondary structure, and toxicity. The structural heterogeneity of aggregated polyglutamine may explain why polyglutamine-containing aggregates could paradoxically be either toxic or neuroprotective.

  6. Mitochondrial Dysfunction: The Road to Alpha-Synuclein Oligomerization in PD

    Directory of Open Access Journals (Sweden)

    A. R. Esteves

    2011-01-01

    Full Text Available While the etiology of Parkinson's disease remains largely elusive, there is accumulating evidence suggesting that mitochondrial dysfunction occurs prior to the onset of symptoms in Parkinson's disease. Mitochondria are remarkably primed to play a vital role in neuronal cell survival since they are key regulators of energy metabolism (as ATP producers, of intracellular calcium homeostasis, of NAD+/NADH ratio, and of endogenous reactive oxygen species production and programmed cell death. In this paper, we focus on mitochondrial dysfunction-mediated alpha-synuclein aggregation. We highlight some of the findings that provide proof of evidence for a mitochondrial metabolism control in Parkinson's disease, namely, mitochondrial regulation of microtubule-dependent cellular traffic and autophagic lysosomal pathway. The knowledge that microtubule alterations may lead to autophagic deficiency and may compromise the cellular degradation mechanisms that culminate in the progressive accumulation of aberrant protein aggregates shields new insights to the way we address Parkinson's disease. In line with this knowledge, an innovative window for new therapeutic strategies aimed to restore microtubule network may be unlocked.

  7. Identification of Bacillus thuringiensis Cry3Aa toxin domain II loop 1 as the binding site of Tenebrio molitor cadherin repeat CR12.

    Science.gov (United States)

    Zúñiga-Navarrete, Fernando; Gómez, Isabel; Peña, Guadalupe; Amaro, Itzel; Ortíz, Ernesto; Becerril, Baltazar; Ibarra, Jorge E; Bravo, Alejandra; Soberón, Mario

    2015-04-01

    Bacillus thuringiensis Cry toxins exert their toxic effect by specific recognition of larval midgut proteins leading to oligomerization of the toxin, membrane insertion and pore formation. The exposed domain II loop regions of Cry toxins have been shown to be involved in receptor binding. Insect cadherins have shown to be functionally involved in toxin binding facilitating toxin oligomerization. Here, we isolated a VHH (VHHA5) antibody by phage display that binds Cry3Aa loop 1 and competed with the binding of Cry3Aa to Tenebrio molitor brush border membranes. VHHA5 also competed with the binding of Cry3Aa to a cadherin fragment (CR12) that was previously shown to be involved in binding and toxicity of Cry3Aa, indicating that Cry3Aa binds CR12 through domain II loop 1. Moreover, we show that a loop 1 mutant, previously characterized to have increased toxicity to T. molitor, displayed a correlative enhanced binding affinity to T. molitor CR12 and to VHHA5. These results show that Cry3Aa domain II loop 1 is a binding site of CR12 T. molitor cadherin. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. TENCompetence Domain Model

    NARCIS (Netherlands)

    2006-01-01

    This is the version 1.1 of the TENCompetence Domain Model (version 1.0 released at 19-6-2006; version 1.1 at 9-11-2008). It contains several files: a) a pdf with the model description, b) three jpg files with class models (also in the pdf), c) a MagicDraw zip file with the model itself, d) a release

  9. SH2 Domain Histochemistry.

    Science.gov (United States)

    Buhs, Sophia; Nollau, Peter

    2017-01-01

    Among posttranslational modifications, the phosphorylation of tyrosine residues is a key modification in cell signaling. Because of its biological importance, characterization of the cellular state of tyrosine phosphorylation is of great interest. Based on the unique properties of endogenously expressed SH2 domains recognizing tyrosine phosphorylated signaling proteins with high specificity we have developed an alternative approach, coined SH2 profiling, enabling us to decipher complex patterns of tyrosine phosphorylation in various normal and cancerous tissues. So far, SH2 profiling has largely been applied for the analysis of protein extracts with the limitation that information on spatial distribution and intensity of tyrosine phosphorylation within a tissue is lost. Here, we describe a novel SH2 domain based strategy for differential characterization of the state of tyrosine phosphorylation in formaldehyde-fixed and paraffin-embedded tissues. This approach demonstrates that SH2 domains may serve as very valuable tools for the analysis of the differential state of tyrosine phosphorylation in primary tissues fixed and processed under conditions frequently applied by routine pathology laboratories.

  10. Human surfactant protein D: SP-D contains a C-type lectin carbohydrate recognition domain.

    Science.gov (United States)

    Rust, K; Grosso, L; Zhang, V; Chang, D; Persson, A; Longmore, W; Cai, G Z; Crouch, E

    1991-10-01

    Lung surfactant protein D (SP-D) shows calcium-dependent binding to specific saccharides, and is similar in domain structure to certain members of the calcium-dependent (C-type) lectin family. Using a degenerate oligomeric probe corresponding to a conserved peptide sequence derived from the amino-terminus of the putative carbohydrate binding domain of rat and bovine SP-D, we screened a human lung cDNA library and isolated a 1.4-kb cDNA for the human protein. The relationship of the cDNA to SP-D was established by several techniques including amino-terminal microsequencing of SP-D-derived peptides, and immunoprecipitation of translation products of transcribed mRNA with monospecific antibodies to SP-D. In addition, antibodies to a synthetic peptide derived from a predicted unique epitope within the carbohydrate recognition domain of SP-D specifically reacted with SP-D. DNA sequencing demonstrated a noncollagenous carboxy-terminal domain that is highly homologous with the carboxy-terminal globular domain of previously described C-type lectins. This domain contains all of the so-called "invariant residues," including four conserved cysteine residues, and shows high homology with the mannose-binding subfamily of C-type lectins. Sequencing also demonstrated an amino-terminal collagenous domain that contains an uninterrupted sequence of 59 Gly-X-Y triplets and that also contains the only identified consensus for asparagine-linked oligosaccharides. The studies demonstrate that SP-D is a member of the C-type lectin family, and confirm predicted structural similarities to conglutinin, SP-D, and the serum mannose binding proteins.

  11. Causes of deaths data, linkages and big data perspectives.

    Science.gov (United States)

    Rey, Grégoire; Bounebache, Karim; Rondet, Claire

    2018-07-01

    The study of cause-specific mortality data is one of the main sources of information for public health monitoring. In most industrialized countries, when a death occurs, it is a legal requirement that a medical certificate based on the international form recommended by World Health Organization's (WHO) is filled in by a physician. The physician reports the causes of death that directly led or contributed to the death on the death certificate. The death certificate is then forwarded to a coding office, where each cause is coded, and one underlying cause is defined, using the rules of the International Classification of Diseases and Related Health Problems, now in its 10th Revision (ICD-10). Recently, a growing number of countries have adopted, or have decided to adopt, the coding software Iris, developed and maintained by an international consortium 1 . This whole standardized production process results in a high and constantly increasing international comparability of cause-specific mortality data. While these data could be used for international comparisons and benchmarking of global burden of diseases, quality of care and prevention policies, there are also many other ways and methods to explore their richness, especially when they are linked with other data sources. Some of these methods are potentially referring to the so-called "big data" field. These methods could be applied both to the production of the data, to the statistical processing of the data, and even more to process these data linked to other databases. In the present note, we depict the main domains in which this new field of methods could be applied. We focus specifically on the context of France, a 65 million inhabitants country with a centralized health data system. Finally we will insist on the importance of data quality, and the specific problematics related to death certification in the forensic medicine domain. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All

  12. Zinc and the iron donor frataxin regulate oligomerization of the scaffold protein to form new Fe-S cluster assembly centers.

    Science.gov (United States)

    Galeano, B K; Ranatunga, W; Gakh, O; Smith, D Y; Thompson, J R; Isaya, G

    2017-06-21

    Early studies of the bacterial Fe-S cluster assembly system provided structural details for how the scaffold protein and the cysteine desulfurase interact. This work and additional work on the yeast and human systems elucidated a conserved mechanism for sulfur donation but did not provide any conclusive insights into the mechanism for iron delivery from the iron donor, frataxin, to the scaffold. We previously showed that oligomerization is a mechanism by which yeast frataxin (Yfh1) can promote assembly of the core machinery for Fe-S cluster synthesis both in vitro and in cells, in such a manner that the scaffold protein, Isu1, can bind to Yfh1 independent of the presence of the cysteine desulfurase, Nfs1. Here, in the absence of Yfh1, Isu1 was found to exist in two forms, one mostly monomeric with limited tendency to dimerize, and one with a strong propensity to oligomerize. Whereas the monomeric form is stabilized by zinc, the loss of zinc promotes formation of dimer and higher order oligomers. However, upon binding to oligomeric Yfh1, both forms take on a similar symmetrical trimeric configuration that places the Fe-S cluster coordinating residues of Isu1 in close proximity of iron-binding residues of Yfh1. This configuration is suitable for docking of Nfs1 in a manner that provides a structural context for coordinate iron and sulfur donation to the scaffold. Moreover, distinct structural features suggest that in physiological conditions the zinc-regulated abundance of monomeric vs. oligomeric Isu1 yields [Yfh1]·[Isu1] complexes with different Isu1 configurations that afford unique functional properties for Fe-S cluster assembly and delivery.

  13. Age- and brain region-dependent α-synuclein oligomerization is attributed to alterations in intrinsic enzymes regulating α-synuclein phosphorylation in aging monkey brains.

    Science.gov (United States)

    Chen, Min; Yang, Weiwei; Li, Xin; Li, Xuran; Wang, Peng; Yue, Feng; Yang, Hui; Chan, Piu; Yu, Shun

    2016-02-23

    We previously reported that the levels of α-syn oligomers, which play pivotal pathogenic roles in age-related Parkinson's disease (PD) and dementia with Lewy bodies, increase heterogeneously in the aging brain. Here, we show that exogenous α-syn incubated with brain extracts from older cynomolgus monkeys and in Lewy body pathology (LBP)-susceptible brain regions (striatum and hippocampus) forms higher amounts of phosphorylated and oligomeric α-syn than that in extracts from younger monkeys and LBP-insusceptible brain regions (cerebellum and occipital cortex). The increased α-syn phosphorylation and oligomerization in the brain extracts from older monkeys and in LBP-susceptible brain regions were associated with higher levels of polo-like kinase 2 (PLK2), an enzyme promoting α-syn phosphorylation, and lower activity of protein phosphatase 2A (PP2A), an enzyme inhibiting α-syn phosphorylation, in these brain extracts. Further, the extent of the age- and brain-dependent increase in α-syn phosphorylation and oligomerization was reduced by inhibition of PLK2 and activation of PP2A. Inversely, phosphorylated α-syn oligomers reduced the activity of PP2A and showed potent cytotoxicity. In addition, the activity of GCase and the levels of ceramide, a product of GCase shown to activate PP2A, were lower in brain extracts from older monkeys and in LBP-susceptible brain regions. Our results suggest a role for altered intrinsic metabolic enzymes in age- and brain region-dependent α-syn oligomerization in aging brains.

  14. Is death our business? Philosophical conflicts over the end-of-life in old age psychiatry.

    Science.gov (United States)

    McKellar, Duncan; Ng, Felicity; Chur-Hansen, Anna

    2016-01-01

    Old age psychiatrists work with end-of-life (EOL) issues and encounter patient deaths, but death and dying have received limited focus in old age psychiatry training and research. This qualitative study explores old age psychiatrists' experience of and approach to working with patients at the EOL. Australian old age psychiatrists were purposively sampled and interviewed in-depth. Data saturation was achieved after nine participant interviews. Verbatim transcripts were analysed for themes, which were independently verified. Two dichotomous overarching themes were identified. Death is not our business reflected participants' experience of working in a mental health framework and incorporated four themes: death should not occur in psychiatry; working in a psychiatric treatment model; keeping a distance from death and unexpected death is a negative experience. Death is our business reflected participants' experience of working in an aged care context and incorporated four themes: death is part of life; encountering the EOL through dementia care; doing EOL work and expected death is a positive experience. Participants reported conflict because of the contradictory domains in which they work. They were comfortable working with patients at the EOL when death was expected, particularly in dementia. By contrast, they struggled with death as an adverse outcome in circumstances influenced by mental health culture, which was characterised by risk management, suicide prevention and a focus on recovery. This study has implications for models of care underpinning old age psychiatry. An integrated person-centred model of care may provide a contextually appropriate approach for practice.

  15. Overdose Deaths Among Homeless Persons

    Science.gov (United States)

    ... Twitter Overdose Deaths Among Homeless Persons January 2013 Homelessness is a persistent problem—nearly 690,000 people ... will ultimately help address the tragic problem of homelessness too, as many homeless people cite drug or ...

  16. Radionuclide evaluation of brain death

    International Nuclear Information System (INIS)

    Pjura, G.A.; Kim, E.E.

    1987-01-01

    The criteria employed for clinical determination of death have evolved in response to advances in life support and other medical technology. The technical feasibility of organ transplantation has amplified the need for a definition of brain death that can be applied in the shortest possible time in the presence of artificial maintenance of vegetative functions, including circulation. Radionuclide cerebral angiography is one of a group of diagnostic procedures that can be employed to confirm the clinical diagnosis of brain death through demonstration of absence of cerebral blood flow. The focus of this work is to assess its use as a confirmatory test for determination of brain death in the context of currently available alternative technologies

  17. Hepatitis E and Maternal Deaths

    Centers for Disease Control (CDC) Podcasts

    Dr. Alain Labrique, assistant professor in the Department of International Health and Department of Epidemiology at the Bloomberg School of Public Health, gives us his perspective on hepatitis E and maternal deaths.

  18. Antiepileptic drugs and intrauterine death

    DEFF Research Database (Denmark)

    Tomson, Torbjörn; Battino, Dina; Bonizzoni, Erminio

    2015-01-01

    ) after prenatal AED exposure. Using EURAP data, we prospectively monitored pregnancies exposed to the 6 most common AED monotherapies and to polytherapy. Intrauterine death (spontaneous abortion and stillbirth combined) was the primary endpoint. RESULTS: Of 7,055 pregnancies exposed to monotherapy...... with lamotrigine (n = 1,910), carbamazepine (n = 1,713), valproic acid (n = 1,171), levetiracetam (n = 324), oxcarbazepine (n = 262), or phenobarbital (n = 260), and to polytherapy (n = 1,415), 632 ended in intrauterine deaths (592 spontaneous abortions and 40 stillbirths). Rates of intrauterine death were similar...... that the risk was greater with polytherapy vs monotherapy (risk ratio [RR] 1.38; 95% CI 1.14-1.66), parental history of MCMs (RR 1.92; 1.20-3.07), maternal age (RR 1.06; 1.04-1.07), and number of previous intrauterine deaths (RR 1.09; 1.00-1.19). The risk was greater with early enrollment and decreased...

  19. Life, Death, and Second Chances

    Science.gov (United States)

    ... Bar Home Current Issue Past Issues Special Section Life, Death, and Second Chances Past Issues / Fall 2007 ... that she was beginning to fear for her life. Was there any hope at all? Dr. Richard ...

  20. Death among children and adolescents

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001915.htm Death among children and adolescents To use the sharing features on this page, ... persons of trust is very important for preventing teen suicide. HOMICIDE Homicide is a complex issue that does ...

  1. Sudden cardiac death in athletes

    Directory of Open Access Journals (Sweden)

    Fábio Camilo Pellegrino dos Santos

    2012-11-01

    Full Text Available ABSTRACT The most accepted definition of sudden cardiac death nowadays is an unexplained death occurred suddenly within one hour of symptom onset. If it was not witnessed, individuals need to had been observed for at least 24 hours before the event and should be discarded the possibility of non cardiac causes of sudden death, pulmonary embolism or extensive malignancy. The term athlete refers to individuals of any age who participate in collective or individual regular physical activity, as well as physical training program for regular competitions. The sudden death of a young athlete, whether amateur or professional, especially during competitions, is always dramatic, with strong negative social impact and in the media. The fact that sports are recommended as a formula for longevity and quality of life makes these events a cause for concern in sports and society in general.

  2. Fournier gangrene and unexpected death.

    Science.gov (United States)

    Bury, Danielle; Byard, Roger W

    2012-11-01

    Fournier gangrene represents a rare but progressive perineal infection that may result in rapid death. A 70-year-old man with poorly controlled diabetes mellitus and alcohol abuse is reported who was found unexpectedly dead. He had last been contacted the night before his death. At autopsy, the most striking finding was deep necrotic ulceration of the scrotum with exposure of underlying deep muscles and testicles, with blood cultures positive for Escherichia coli. Death was, therefore, attributed to necrotic ulceration/gangrene of the perineum (Fournier gangrene) that was due to E. coli sepsis with underlying contributing factors of diabetes mellitus and alcoholism. In addition there was morbid obesity (body mass index 46.9), cirrhosis of the liver, and marked focal coronary artery atherosclerosis with significant cardiomegaly. Fournier gangrene may be an extremely aggressive condition that can result in rapid death, as was demonstrated by the rapid progression in the reported case. © 2012 American Academy of Forensic Sciences.

  3. 38 CFR 3.211 - Death.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Death. 3.211 Section 3..., Compensation, and Dependency and Indemnity Compensation Evidence Requirements § 3.211 Death. Death should be... community where death occurred. (2) A copy of a coroner's report of death or a verdict of a coroner's jury...

  4. Sudden death in eating disorders

    Directory of Open Access Journals (Sweden)

    Jáuregui-Garrido B

    2012-02-01

    Full Text Available Beatriz Jáuregui-Garrido1, Ignacio Jáuregui-Lobera2,31Department of Cardiology, University Hospital Virgen del Rocío, 2Behavioral Sciences Institute, 3Pablo de Olavide University, Seville, SpainAbstract: Eating disorders are usually associated with an increased risk of premature death with a wide range of rates and causes of mortality. “Sudden death” has been defined as the abrupt and unexpected occurrence of fatality for which no satisfactory explanation of the cause can be ascertained. In many cases of sudden death, autopsies do not clarify the main cause. Cardiovascular complications are usually involved in these deaths. The purpose of this review was to report an update of the existing literature data on the main findings with respect to sudden death in eating disorders by means of a search conducted in PubMed. The most relevant conclusion of this review seems to be that the main causes of sudden death in eating disorders are those related to cardiovascular complications. The predictive value of the increased QT interval dispersion as a marker of sudden acute ventricular arrhythmia and death has been demonstrated. Eating disorder patients with severe cardiovascular symptoms should be hospitalized. In general, with respect to sudden death in eating disorders, some findings (eg, long-term eating disorders, chronic hypokalemia, chronically low plasma albumin, and QT intervals >600 milliseconds must be taken into account, and it must be highlighted that during refeeding, the adverse effects of hypophosphatemia include cardiac failure. Monitoring vital signs and performing electrocardiograms and serial measurements of plasma potassium are relevant during the treatment of eating disorder patients.Keywords: sudden death, cardiovascular complications, refeeding syndrome, QT interval, hypokalemia

  5. Autoerotic death due to electrocution

    Directory of Open Access Journals (Sweden)

    Piotr Arkuszewski

    2014-08-01

    Full Text Available Autoerotic death is a very rare case in forensic medicine. It is usually caused by asphyxia, but other reasons are also possible. Herein we present a case of autoerotic death due to electrocution caused by a self-made electrical device. The device was constructed to increase sexual feelings through stimulation of the scrotal area.

  6. Faith healers, myths and deaths.

    Science.gov (United States)

    Wasti, Harihar; Kanchan, Tanuj; Acharya, Jenash

    2015-09-01

    Science and myth have been closely linked and argued upon by philosophers, educationalists, scientists, enthusiasts and the general public. Faith healing, when added as an adjuvant or alternative aid to medical science, will not necessarily be confined to mere arguments and debates but may also give rise to series of complications, medical emergencies and even result in death. We present an unusual case where reliance on faith healing led to the death of a young man. © The Author(s) 2015.

  7. Death signals by environmental pollutants

    International Nuclear Information System (INIS)

    Krug, H.F.

    2002-01-01

    Life and death are directly involved in the normal development of all multicellular organisms. Defects in the regulation of the mechanism of programmed cell death (apoptosis) contribute to many diseases as well as in the toxic effects of xenobiotics. Here it is described which elements of the apoptotic machinery are possible targets of hydrocarbons and metal compounds, prominent environmental pollutants. Moreover, it is shown that cytotoxic rather than cytostatic therapies might be most effective in treatment of cancer. (orig.)

  8. Domain decomposition method for solving elliptic problems in unbounded domains

    International Nuclear Information System (INIS)

    Khoromskij, B.N.; Mazurkevich, G.E.; Zhidkov, E.P.

    1991-01-01

    Computational aspects of the box domain decomposition (DD) method for solving boundary value problems in an unbounded domain are discussed. A new variant of the DD-method for elliptic problems in unbounded domains is suggested. It is based on the partitioning of an unbounded domain adapted to the given asymptotic decay of an unknown function at infinity. The comparison of computational expenditures is given for boundary integral method and the suggested DD-algorithm. 29 refs.; 2 figs.; 2 tabs

  9. Fouling behaviors of polybenzimidazole (PBI)-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) hollow fiber membranes for engineering osmosis processes

    KAUST Repository

    Chen, Sicong; Fu, Xiuzhu; Chung, Neal Tai-Shung

    2014-01-01

    This paper investigated the individual effects of reverse salt flux and permeate flux on fouling behaviors of as-spun and annealed polybenzimidazole (PBI)-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) hollow fiber membranes under forward osmosis (FO) and pressure retarded osmosis (PRO) processes. Two types of membrane fouling had been studied; namely, inorganic fouling (CaSO4·2H2O gypsum scaling) during FO operations and organic fouling (sodium alginate fouling) during PRO operations. It is found that gypsum scaling on the membrane surface may be inhibited and even eliminated with an increase in reverse MgCl2 flux due to competitive formations of MgSO4° and CaSO4·2H2O. In contrast, the increase of reverse NaCl flux exhibits a slight enhancement on alginate fouling in both FO and PRO processes. Comparing to the reverse salt flux, the permeate flux always plays a dominant role in fouling. Therefore, lesser fouling has been observed on the membrane surface under the pressurized PRO process than FO process because the reduced initial flux mitigates the fouling phenomena more significantly than the enhancement caused by an increase in reverse NaCl flux. © 2013 Elsevier B.V.

  10. Increased serum cartilage oligomeric matrix protein levels and decreased patellar bone mineral density in patients with chondromalacia patellae.

    Science.gov (United States)

    Murphy, E; FitzGerald, O; Saxne, T; Bresnihan, B

    2002-11-01

    Chondromalacia patellae is a potentially disabling disorder characterised by features of patellar cartilage degradation. To evaluate markers of cartilage and bone turnover in patients with chondromalacia patellae. 18 patients with chondromalacia patellae were studied. Serum cartilage oligomeric matrix protein (s-COMP) and bone sialoprotein (s-BSP) levels were measured by enzyme linked immunosorbent assay (ELISA) and compared with those of age and sex matched healthy control subjects. Periarticular bone mineral density (BMD) of both knee joints was assessed by dual energy x ray absorptiometry (DXA). s-COMP levels were significantly raised in all patients with chondromalacia patellae compared with healthy control subjects (p=0.0001). s-BSP levels did not differ significantly between the groups (p=0.41). BMD of the patella was significantly reduced in patients with chondromalacia patellae compared with the control subjects (p=0.016). In patients with bilateral chondromalacia patellae, BMD of the patella was lower in the more symptomatic knee joint (p=0.005). Changes in periarticular BMD were localised to the patella and were not present in femoral regions. Neither s-COMP (p=0.18) nor s-BSP (p=0.40) levels correlated with patellar BMD. Increased s-COMP levels, reflecting cartilage degradation, and reduced BMD localised to the patella may represent clinically useful markers in the diagnosis and monitoring of patients with chondromalacia patellae. Measures of cartilage degradation did not correlate with loss of patellar bone density, suggesting dissociated pathophysiological mechanisms.

  11. Development of Biodegradable Poly(citrate)-Polyhedral Oligomeric Silsesquioxanes Hybrid Elastomers with High Mechanical Properties and Osteogenic Differentiation Activity.

    Science.gov (United States)

    Du, Yuzhang; Yu, Meng; Chen, Xiaofeng; Ma, Peter X; Lei, Bo

    2016-02-10

    Biodegradable elastomeric biomaterials have attracted much attention in tissue engineering due to their biomimetic viscoelastic behavior and biocompatibility. However, the low mechanical stability at hydrated state, fast biodegradation in vivo, and poor osteogenic activity greatly limited bioelastomers applications in bone tissue regeneration. Herein, we develop a series of poly(octanediol citrate)-polyhedral oligomeric silsesquioxanes (POC-POSS) hybrids with highly tunable elastomeric behavior (hydrated state) and biodegradation and osteoblasts biocompatibility through a facile one-pot thermal polymerization strategy. POC-POSS hybrids show significantly improved stiffness and ductility in either dry or hydrated conditions, as well as good antibiodegradation ability (20-50% weight loss in 3 months). POC-POSS hybrids exhibit significantly enhanced osteogenic differentiation through upregulating alkaline phosphatase (ALP) activity, calcium deposition, and expression of osteogenic markers (ALPL, BGLAP, and Runx2). The high mechanical stability at hydrated state and enhanced osteogenic activity make POC-POSS hybrid elastomers promising as scaffolds and nanoscale vehicles for bone tissue regeneration and drug delivery. This study may also provide a new strategy (controlling the stiffness under hydrated condition) to design advanced hybrid biomaterials with high mechanical properties under physiological condition for tissue regeneration applications.

  12. Pleiotropic benefit of monomeric and oligomeric flavanols on vascular health--a randomized controlled clinical pilot study.

    Science.gov (United States)

    Weseler, Antje R; Ruijters, Erik J B; Drittij-Reijnders, Marie-José; Reesink, Koen D; Haenen, Guido R M M; Bast, Aalt

    2011-01-01

    Cardiovascular diseases are expanding to a major social-economic burden in the Western World and undermine man's deep desire for healthy ageing. Epidemiological studies suggest that flavanol-rich foods (e.g. grapes, wine, chocolate) sustain cardiovascular health. For an evidenced-based application, however, sound clinical data on their efficacy are strongly demanded. In a double-blind, randomized, placebo-controlled intervention study we supplemented 28 male smokers with 200 mg per day of monomeric and oligomeric flavanols (MOF) from grape seeds. At baseline, after 4 and 8 weeks we measured macro- and microvascular function and a cluster of systemic biomarkers for major pathological processes occurring in the vasculature: disturbances in lipid metabolism and cellular redox balance, and activation of inflammatory cells and platelets. In the MOF group serum total cholesterol and LDL decreased significantly (P ≤ 0.05) by 5% (n = 11) and 7% (n = 9), respectively in volunteers with elevated baseline levels. Additionally, after 8 weeks the ratio of glutathione to glutathione disulphide in erythrocytes rose from baseline by 22% (n = 15, Pbenefit of an 8 weeks supplementation with 200 mg/d MOF in humans. ClinicalTrials.gov NCT00742287.

  13. Preparation of polyhedral oligomeric silsesquioxane based hybrid monoliths by ring-opening polymerization for capillary LC and CEC.

    Science.gov (United States)

    Lin, Hui; Zhang, Zhenbin; Dong, Jing; Liu, Zhongshan; Ou, Junjie; Zou, Hanfa

    2013-09-01

    A new organic-inorganic hybrid monolith was prepared by the ring-opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxane (POSS) with 1,4-butanediamine (BDA) using 1-propanol, 1,4-butanediol, and PEG 10,000 as a porogenic system. Benefiting from the moderate phase separation process, the resulting poly(POSS-co-BDA) hybrid monolith possessed a uniform microstructure and exhibited excellent performance in chromatographic applications. Neutral, acidic, and basic compounds were successfully separated on the hybrid monolith in capillary LC (cLC), and high column efficiencies were achieved in all of the separations. In addition, as the amino groups could generate a strong EOF, the hybrid monolith was also applied in CEC for the separation of neutral and polar compounds, and a satisfactory performance was obtained. These results demonstrate that the poly(POSS-co-BDA) hybrid monolith is a good separation media in chromatographic separations of various types of compounds by both cLC and CEC. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Structural Analysis of Polyhedral Oligomeric Silsesquioxane Coated SiC Nanoparticles and Their Applications in Thermoset Polymers

    International Nuclear Information System (INIS)

    Reza-E-Rabby, M.; Jeelani, Sh.; Rangari, V. K.

    2015-01-01

    The SiC nanoparticles (NPs) were sonochemically coated with Octa Isobutyl (OI) polyhedral oligomeric silsesquioxane (POSS) to create a compatible interface between particle and thermoset polymer. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) techniques were used to analyze the structure of OI-POSS coated SiC nanoparticles. These results revealed the formation of a covalent bonding between SiC and OI-POSS. The transmission electron microscopy (TEM) analysis of OI-POSS coated SiC nanoparticles has also shown the indication of attachment between these two nanoparticles. The OI-POSS coated SiC nanoparticles were further reinforced into a thermoset resin system in order to evaluate mechanical and thermal properties of nano composites. The flexural strength, modulus, and glass transition temperature were found to be enhanced while SiC and OI-POSS coated SiC were infused into epoxy system compared to those properties of neat epoxy resin

  15. Glycerol-Induced Aggregation of the Oligomeric L-Asparaginase II from E. coli Monitored with ATR-FTIR

    Directory of Open Access Journals (Sweden)

    Koba Adeishvili

    2001-06-01

    Full Text Available Abstract: In this paper attenuated total reflectance Fourier transform infrared spectroscopy has been employed for the study of the structural composition of aggregates of the oligomeric L-asparaginase II from E.coli formed in the presence of glycerol after the induction of refolding of the protein. Apart from the perfect coincidence of the secondary structure composition of EcA2 as determined by FTIR and crystallography [1], it has also been shown that secondary structure of protein in asparaginase deposits is similar to that of the native conformation: 20.7% extended, 22.3% disordered, 31.4% helix and 25.6% turn/bend/β sheet. Certain structural similarities in the range of experimental error was observed for all three protein deposits presented in this paper, indicating a common structural basis for the composition of this types of aggregates. It is concluded that in the constitution of such precipitates, a partially folded (molten globule like state(s is involved, and its stabilisation is a key factor leading to the aggregation. The results presented in this paper might serve to be a good explanation and an excellent basis for the fundamental theory of protein (oligomers precipitation by osmotic substances.

  16. Functional significance of the oligomeric structure of the Na,K-pump from radiation inactivation and ligand binding

    International Nuclear Information System (INIS)

    Norby, J.G.; Jensen, J.

    1991-01-01

    The present article is concerned with the oligomeric structure and function of the Na,K-pump (Na,K-ATPase). The questions we have addressed, using radiation inactivation and target size analysis as well as ligand binding, are whether the minimal structural unit and the functional unit have more than one molecule of the catalytic subunit, alpha. The authors first discuss the fundamentals of the radiation inactivation method and emphasize the necessity for rigorous internal standardization with enzymes of known molecular mass. They then demonstrate that the radiation inactivation of Na,K-ATPase is a stepwise process which leads to intermediary fragments of the alpha-subunit with partial catalytic activity. From the target size analysis it is most likely that the membrane-bound Na,K-ATPase is structurally organized as a diprotomer containing two alpha-subunits. Determination of ADP- and ouabain-binding site stoichiometry favors a theory with one substrate site per (alpha beta) 2. 47 references

  17. Continued biological investigations of boron-rich oligomeric phosphate diesters (OPDs). Tumor-selective boron agents for BNCT

    International Nuclear Information System (INIS)

    Lee, Mark W.; Shelly, Kenneth; Kane, Robert R.; Hawthorne, M. Frederick

    2006-01-01

    Clinical success of Boron Neutron Capture Therapy will rely on the selective intracellular delivery of high concentrations of boron-10 to tumor tissue. In order for a boron agent to facilitate clinical success, the simultaneous needs of obtaining a high tumor dose, high tumor selectivity, and low systemic toxicity must be realized. Boron-rich oligomeric phosphate diesters (OPDs) are a class of highly water-soluble compounds containing up to 40% boron by weight. Previous work in our groups demonstrated that once placed in the cytoplasm of tumor cells, OPDs quickly accumulate within the cell nucleus. The objective of the current study was to determine the biodistribution of seven different free OPDs in BALB/c mice bearing EMT6 tumors. Fructose solutions containing between 1.4 and 6.4 micrograms of boron per gram of tissue were interveinously injected in mice seven to ten days after tumor implantation. At intervals during the study, animals were euthanized and samples of tumor, blood, liver, kidney, brain and skin were collected and analyzed for boron content using ICP-AES. Tumor boron concentrations of between 5 and 29 ppm were achieved and maintained over the 72-hour time course of each experiment. Several OPDs demonstrated high tumor selectivity with one oligomer exhibiting a tumor to blood ratio of 35:1. The apparent toxicity of each oligomer was assessed through animal behavior during the experiment and necropsy of each animal upon sacrifice. (author)

  18. Structural Analysis of Polyhedral Oligomeric Silsesquioxane Coated SiC Nanoparticles and Their Applications in Thermoset Polymers

    Directory of Open Access Journals (Sweden)

    Md. Reza-E-Rabby

    2015-01-01

    Full Text Available The SiC nanoparticles (NPs were sonochemically coated with OctaIsobutyl (OI polyhedral oligomeric silsesquioxane (POSS to create a compatible interface between particle and thermoset polymer. X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectroscopy (FTIR, and X-ray diffraction (XRD techniques were used to analyze the structure of OI-POSS coated SiC nanoparticles. These results revealed the formation of a covalent bonding between SiC and OI-POSS. The transmission electron microscopy (TEM analysis of OI-POSS coated SiC nanoparticles has also shown the indication of attachment between these two nanoparticles. The OI-POSS coated SiC nanoparticles were further reinforced into a thermoset resin system in order to evaluate mechanical and thermal properties of nanocomposites. The flexural strength, modulus, and glass transition temperature were found to be enhanced while SiC and OI-POSS coated SiC were infused into epoxy system compared to those properties of neat epoxy resin.

  19. Unusual Emission of Polystyrene-Based Alternating Copolymers Incorporating Aminobutyl Maleimide Fluorophore-Containing Polyhedral Oligomeric Silsesquioxane Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohamed Gamal Mohamed

    2017-03-01

    Full Text Available In this study, we synthesized an unusual 2-aminobutyl maleimide isobutyl polyhedral oligomeric silsesquioxane (MIPOSS-NHBu monomer lacking conventional fluorescent groups. We then prepared poly(styrene-alt-2-aminobutyl maleimide isobutyl POSS [poly(S-alt-MIPOSS-NHBu] and poly(4-acetoxystyrene-alt-2-aminobutyl maleimide isobutyl POSS [poly(AS-alt-MIPOSS-NHBu] copolymers through facile free radical copolymerizations using azobisisobutyronitrile as the initiator and tetrahydrofuran as the solvent. A poly(4-hydroxystyrene-alt-2-aminobutyl maleimide isobutyl POSS [poly(HS-alt-MIPOSS-NHBu] copolymer was prepared through acetoxyl hydrazinolysis of poly(AS-alt-MIPOSS-NHBu. We employed 1H, 13C, and 29Si nuclear magnetic resonance spectroscopy; Fourier transform infrared spectroscopy; differential scanning calorimetry; and photoluminescence spectroscopy to investigate the structures and the thermal and optical properties of the monomers and novel POSS-containing alternating copolymers. Intramolecular hydrogen bonding between the amino and dihydrofuran-2,5-dione group and clustering of the locked C=O groups from the POSS nanoparticles in the MIPOSS-NHBu units restricted the intramolecular motion of the polymer chain, causing it to exhibit strong light emission. As a result, the MIPOSS-NHBu monomer and the poly(AS-alt-MIPOSS-NHBu copolymer both have potential applicability in the detection of metal ions with good selectivity.

  20. Non-transferrin-bound iron (NTBI uptake by T lymphocytes: evidence for the selective acquisition of oligomeric ferric citrate species.

    Directory of Open Access Journals (Sweden)

    Joao Arezes

    Full Text Available Iron is an essential nutrient in several biological processes such as oxygen transport, DNA replication and erythropoiesis. Plasma iron normally circulates bound to transferrin. In iron overload disorders, however, iron concentrations exceed transferrin binding capacity and iron appears complexed with low molecular weight molecules, known as non-transferrin-bound iron (NTBI. NTBI is responsible for the toxicity associated with iron-overload pathologies but the mechanisms leading to NTBI uptake are not fully understood. Here we show for the first time that T lymphocytes are able to take up and accumulate NTBI in a manner that resembles that of hepatocytes. Moreover, we show that both hepatocytes and T lymphocytes take up the oligomeric Fe3Cit3 preferentially to other iron-citrate species, suggesting the existence of a selective NTBI carrier. These results provide a tool for the identification of the still elusive ferric-citrate cellular carrier and may also open a new pathway towards the design of more efficient iron chelators for the treatment of iron overload disorders.

  1. Fouling behaviors of polybenzimidazole (PBI)-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) hollow fiber membranes for engineering osmosis processes

    KAUST Repository

    Chen, Sicong

    2014-02-01

    This paper investigated the individual effects of reverse salt flux and permeate flux on fouling behaviors of as-spun and annealed polybenzimidazole (PBI)-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) hollow fiber membranes under forward osmosis (FO) and pressure retarded osmosis (PRO) processes. Two types of membrane fouling had been studied; namely, inorganic fouling (CaSO4·2H2O gypsum scaling) during FO operations and organic fouling (sodium alginate fouling) during PRO operations. It is found that gypsum scaling on the membrane surface may be inhibited and even eliminated with an increase in reverse MgCl2 flux due to competitive formations of MgSO4° and CaSO4·2H2O. In contrast, the increase of reverse NaCl flux exhibits a slight enhancement on alginate fouling in both FO and PRO processes. Comparing to the reverse salt flux, the permeate flux always plays a dominant role in fouling. Therefore, lesser fouling has been observed on the membrane surface under the pressurized PRO process than FO process because the reduced initial flux mitigates the fouling phenomena more significantly than the enhancement caused by an increase in reverse NaCl flux. © 2013 Elsevier B.V.

  2. Functional Domain Driven Design

    OpenAIRE

    Herrera Guzmán, Sergio

    2016-01-01

    Las tecnologías están en constante expansión y evolución, diseñando nuevas técnicas para cumplir con su fin. En el desarrollo de software, las herramientas y pautas para la elaboración de productos software constituyen una pieza en constante evolución, necesarias para la toma de decisiones sobre los proyectos a realizar. Uno de los arquetipos para el desarrollo de software es el denominado Domain Driven Design, donde es importante conocer ampliamente el negocio que se desea modelar en form...

  3. Feature-level domain adaptation

    DEFF Research Database (Denmark)

    Kouw, Wouter M.; Van Der Maaten, Laurens J P; Krijthe, Jesse H.

    2016-01-01

    -level domain adaptation (flda), that models the dependence between the two domains by means of a feature-level transfer model that is trained to describe the transfer from source to target domain. Subsequently, we train a domain-adapted classifier by minimizing the expected loss under the resulting transfer...... modeled via a dropout distribution, which allows the classiffier to adapt to differences in the marginal probability of features in the source and the target domain. Our experiments on several real-world problems show that flda performs on par with state-of-the-art domainadaptation techniques.......Domain adaptation is the supervised learning setting in which the training and test data are sampled from different distributions: training data is sampled from a source domain, whilst test data is sampled from a target domain. This paper proposes and studies an approach, called feature...

  4. Compensating for Incomplete Domain Knowledge

    National Research Council Canada - National Science Library

    Scott, Lynn M; Drezner, Steve; Rue, Rachel; Reyes, Jesse

    2007-01-01

    .... First, many senior leader positions require experience in more than one functional or operational domain, but it is difficult to develop a corps of senior leaders with all the required combinations of domain knowledge...

  5. Glycosylation as a Main Regulator of Growth and Death Factor Receptors Signaling

    Directory of Open Access Journals (Sweden)

    Inês Gomes Ferreira

    2018-02-01

    Full Text Available Glycosylation is a very frequent and functionally important post-translational protein modification that undergoes profound changes in cancer. Growth and death factor receptors and plasma membrane glycoproteins, which upon activation by extracellular ligands trigger a signal transduction cascade, are targets of several molecular anti-cancer drugs. In this review, we provide a thorough picture of the mechanisms bywhich glycosylation affects the activity of growth and death factor receptors in normal and pathological conditions. Glycosylation affects receptor activity through three non-mutually exclusive basic mechanisms: (1 by directly regulating intracellular transport, ligand binding, oligomerization and signaling of receptors; (2 through the binding of receptor carbohydrate structures to galectins, forming a lattice thatregulates receptor turnover on the plasma membrane; and (3 by receptor interaction with gangliosides inside membrane microdomains. Some carbohydrate chains, for example core fucose and β1,6-branching, exert a stimulatory effect on all receptors, while other structures exert opposite effects on different receptors or in different cellular contexts. In light of the crucial role played by glycosylation in the regulation of receptor activity, the development of next-generation drugs targeting glyco-epitopes of growth factor receptors should be considered a therapeutically interesting goal.

  6. Ten Leading Causes of Death and Injury

    Science.gov (United States)

    ... Overdose Traumatic Brain Injury Violence Prevention Ten Leading Causes of Death and Injury Recommend on Facebook Tweet Share Compartir ... in Hospital Emergency Departments, United States – 2014 Leading Causes of Death Charts Causes of Death by Age Group 2016 [ ...

  7. Ligand binding by PDZ domains

    DEFF Research Database (Denmark)

    Chi, Celestine N.; Bach, Anders; Strømgaard, Kristian

    2012-01-01

    , for example, are particularly rich in these domains. The general function of PDZ domains is to bring proteins together within the appropriate cellular compartment, thereby facilitating scaffolding, signaling, and trafficking events. The many functions of PDZ domains under normal physiological as well...... as pathological conditions have been reviewed recently. In this review, we focus on the molecular details of how PDZ domains bind their protein ligands and their potential as drug targets in this context....

  8. Summarization by domain ontology navigation

    DEFF Research Database (Denmark)

    Andreasen, Troels; Bulskov, Henrik

    2013-01-01

    of the subject. In between these two extremes, conceptual summaries encompass selected concepts derived using background knowledge. We address in this paper an approach where conceptual summaries are provided through a conceptualization as given by an ontology. The ontology guiding the summarization can...... be a simple taxonomy or a generative domain ontology. A domain ontology can be provided by a preanalysis of a domain corpus and can be used to condense improved summaries that better reflects the conceptualization of a given domain....

  9. Crystal optimization and preliminary diffraction data analysis of the SCAN domain of Zfp206

    International Nuclear Information System (INIS)

    Liang, Yu; Choo, Siew Hua; Rossbach, Michael; Baburajendran, Nithya; Palasingam, Paaventhan; Kolatkar, Prasanna R

    2012-01-01

    Crystals of the SCAN domain of Zfp206 are tetragonal, belonging to space group I422 with unit-cell parameters a = 67.57, c = 87.54 Å and one molecule in the asymmetric unit, and diffract to 1.85 Å resolution. Zfp206 (also named Zscan10) is a transcription factor that plays an important role in maintaining the pluripotent state of embryonic stem cells. Zfp206 is a member of the SCAN-domain family of C 2 H 2 zinc-finger transcription factors. The SCAN domain is a highly conserved motif of 84 residues which mediates the self-association of and heterodimerization between SCAN-domain family transcription factors. The SCAN domain may therefore be the key to the selective oligomerization of and may combinatorially enhance the regulatory versatility of C 2 H 2 zinc fingers. This paper describes crystallization attempts with the SCAN domain of Zfp206 (Zfp206SCAN) and optimization strategies to obtain diffraction-quality crystals. The best diffracting crystal was grown in a solution consisting of 0.3 M ammonium sulfate, 0.1 M Tris–HCl pH 8.6, 25% PEG 3350, 0.1 M ethylenediaminetetraacetic acid disodium salt dehydrate (EDTA) using the hanging-drop vapour-diffusion technique. Optimized crystals diffracted to 1.85 Å resolution and belonged to space group I422, with unit-cell parameters a = 67.57, c = 87.54 Å. A Matthews analysis indicated the presence of one Zfp206SCAN molecule per asymmetric unit

  10. Death in life or life in death? Dementia's ontological challenge.

    Science.gov (United States)

    Macdonald, Gaynor

    2018-01-01

    Is it possible to end one's life well with dementia? The perception of dementia as death brought into life flows from ideas about humanness embedded in medicine's Cartesian paradigm. Dementia as incurable brain disease exacerbates negativity. But the real impact of dementia is that it changes social relations: to live well with dementia requires a relational not Cartesian understanding of life. A relational ontology prioritizes social health: to live is to be held in connection. Negativity produces the disconnection that is death, with or without disease. When people with dementia are held in connection, they live a better life.

  11. Expansion of protein domain repeats.

    Directory of Open Access Journals (Sweden)

    Asa K Björklund

    2006-08-01

    Full Text Available Many proteins, especially in eukaryotes, contain tandem repeats of several domains from the same family. These repeats have a variety of binding properties and are involved in protein-protein interactions as well as binding to other ligands such as DNA and RNA. The rapid expansion of protein domain repeats is assumed to have evolved through internal tandem duplications. However, the exact mechanisms behind these tandem duplications are not well-understood. Here, we have studied the evolution, function, protein structure, gene structure, and phylogenetic distribution of domain repeats. For this purpose we have assigned Pfam-A domain families to 24 proteomes with more sensitive domain assignments in the repeat regions. These assignments confirmed previous findings that eukaryotes, and in particular vertebrates, contain a much higher fraction of proteins with repeats compared with prokaryotes. The internal sequence similarity in each protein revealed that the domain repeats are often expanded through duplications of several domains at a time, while the duplication of one domain is less common. Many of the repeats appear to have been duplicated in the middle of the repeat region. This is in strong contrast to the evolution of other proteins that mainly works through additions of single domains at either terminus. Further, we found that some domain families show distinct duplication patterns, e.g., nebulin domains have mainly been expanded with a unit of seven domains at a time, while duplications of other domain families involve varying numbers of domains. Finally, no common mechanism for the expansion of all repeats could be detected. We found that the duplication patterns show no dependence on the size of the domains. Further, repeat expansion in some families can possibly be explained by shuffling of exons. However, exon shuffling could not have created all repeats.

  12. Glutathione in Cancer Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Angel L. [Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 17 Av. Blasco Ibanez, 46010 Valencia (Spain); Mena, Salvador [Green Molecular SL, Pol. Ind. La Coma-Parc Cientific, 46190 Paterna, Valencia (Spain); Estrela, Jose M., E-mail: jose.m.estrela@uv.es [Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 17 Av. Blasco Ibanez, 46010 Valencia (Spain)

    2011-03-11

    Glutathione (L-γ-glutamyl-L-cysteinyl-glycine; GSH) in cancer cells is particularly relevant in the regulation of carcinogenic mechanisms; sensitivity against cytotoxic drugs, ionizing radiations, and some cytokines; DNA synthesis; and cell proliferation and death. The intracellular thiol redox state (controlled by GSH) is one of the endogenous effectors involved in regulating the mitochondrial permeability transition pore complex and, in consequence, thiol oxidation can be a causal factor in the mitochondrion-based mechanism that leads to cell death. Nevertheless GSH depletion is a common feature not only of apoptosis but also of other types of cell death. Indeed rates of GSH synthesis and fluxes regulate its levels in cellular compartments, and potentially influence switches among different mechanisms of death. How changes in gene expression, post-translational modifications of proteins, and signaling cascades are implicated will be discussed. Furthermore, this review will finally analyze whether GSH depletion may facilitate cancer cell death under in vivo conditions, and how this can be applied to cancer therapy.

  13. Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial Endosymbiont.

    Directory of Open Access Journals (Sweden)

    Weiwen Zheng

    Full Text Available Programmed cell death (PCD is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20% of the total cell population, depending on the cell type and host developmental stage. Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays, together with visualization of cytoskeleton alterations (FITC-phalloidin staining, showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20 further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom.

  14. Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial) Endosymbiont

    Science.gov (United States)

    Zheng, Weiwen; Rasmussen, Ulla; Zheng, Siping; Bao, Xiaodong; Chen, Bin; Gao, Yuan; Guan, Xiong; Larsson, John; Bergman, Birgitta

    2013-01-01

    Programmed cell death (PCD) is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20%) of the total cell population, depending on the cell type and host developmental stage. Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays), together with visualization of cytoskeleton alterations (FITC-phalloidin staining), showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20) further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom. PMID:23822984

  15. Structure of the effector-binding domain of the arabinose repressor AraR from Bacillus subtilis

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    Procházková, Kateřina; Čermáková, Kateřina [Academy of Sciences of the Czech Republic, Flemingovo nam. 2, Prague 6 (Czech Republic); Pachl, Petr; Sieglová, Irena [Academy of Sciences of the Czech Republic, Flemingovo nam. 2, Prague 6 (Czech Republic); Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 (Czech Republic); Fábry, Milan [Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 (Czech Republic); Otwinowski, Zbyszek [UT Southwestern Medical Center, Dallas, Texas (United States); Řezáčová, Pavlína, E-mail: rezacova@uochb.cas.cz [Academy of Sciences of the Czech Republic, Flemingovo nam. 2, Prague 6 (Czech Republic); Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 (Czech Republic)

    2012-02-01

    The crystal structure of the effector-binding domain of the transcriptional repressor AraR from B. subtilis in complex with the effector molecule (l-arabinose) was determined at 2.2 Å resolution. A detailed analysis of the crystal identified a dimer organization that is distinctive from that of other members of the GalR/LacI family. In Bacillus subtilis, the arabinose repressor AraR negatively controls the expression of genes in the metabolic pathway of arabinose-containing polysaccharides. The protein is composed of two domains of different phylogenetic origin and function: an N-terminal DNA-binding domain belonging to the GntR family and a C-terminal effector-binding domain that shows similarity to members of the GalR/LacI family. The crystal structure of the C-terminal effector-binding domain of AraR in complex with the effector l-arabinose has been determined at 2.2 Å resolution. The l-arabinose binding affinity was characterized by isothermal titration calorimetry and differential scanning fluorimetry; the K{sub d} value was 8.4 ± 0.4 µM. The effect of l-arabinose on the protein oligomeric state was investigated in solution and detailed analysis of the crystal identified a dimer organization which is distinctive from that of other members of the GalR/LacI family.

  16. Sudden unexpected death in infancy in Denmark

    DEFF Research Database (Denmark)

    Winkel, Bo Gregers; Holst, Anders Gaarsdal; Theilade, Juliane

    2011-01-01

    Abstract Background. Incidence of sudden unexpected death in infancy (SUDI) and sudden infant death syndrome (SIDS) differs among studies and non-autopsied cases are difficult to assess. Objectives. To investigate causes of sudden death in infancy in a nationwide setting. Validate the use...... of the ICD-10 code for SIDS (R95) in the Danish Cause of Death registry. Design. A retrospective analysis of all infant deaths (death certificates and autopsy reports were read. Results. We identified 192 SUDI cases (10% of total deaths, 0.42 per 1000 births......) with autopsy performed in 87% of cases. In total, 49% of autopsied SUDI cases were defined as SIDS (5% of all deaths, 0.22 per 1000 births); Cardiac cause of death was denoted in 24% of cases. The Danish Cause of Death Registry misclassified 30% of SIDS cases. Conclusions. A large proportion of infant deaths...

  17. Death from a driverless vehicle.

    Science.gov (United States)

    Das, Siddhartha; Menezes, Ritesh G

    2018-03-01

    Road traffic accidents are a major cause of fatalities around the world, and a number of deaths are caused by moving traffic on public roads. Deaths from vehicles that are off the highway may be called non-traffic fatalities which can be due to a vehicle reversing, carbon monoxide poisoning, weather-induced over-heating inside the vehicle and electric windows. Children (and animals) are the usual victims. We report a case from India where a man was found lying dead by the roadside with a lorry nearby. The autopsy findings indicated that he had been run over, but as there was no history of a vehicular collision and with no eyewitnesses, the investigators were unsure of the probable sequence of events that led to his death. The autopsy findings, history, circumstantial evidence and chemical analysis enabled us to work out what had happened.

  18. Introduction: Mediating and Remediating Death

    DEFF Research Database (Denmark)

    Christensen, Dorthe Refslund; Sandvik, Kjetil

    2014-01-01

    In this second volume we explore how people, groups and institutions deal with death through processes of mediation (the presentation of something through media), remediation (the representation of one medium in another, see below) and mediatization (the process through which core elements...... of a social or cultural activity assume media form, see below). The volume presents a wide variety of ethnographies of death from Norway, Finland, Sweden, the US, Papua New Guinea, Bosnia and Hercegovina, Libya, Tibet, Uganda and Denmark as well as a number of online sites and social media material....... These are analyzed through a vast number of theoretical and analytical perspectives in order to investigate how very diverse practices surrounding death and dying - mourning and commemoration, ritualization, politicization, re-enactment, traditionalization, activism or documentarism: private or public, offline...

  19. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca; Auken, Esben; Christiansen, Anders Vest

    2012-01-01

    Time-domain-induced polarization has significantly broadened its field of reference during the last decade, from mineral exploration to environmental geophysics, e.g., for clay and peat identification and landfill characterization. Though, insufficient modeling tools have hitherto limited the use...... of time-domaininduced polarization for wider purposes. For these reasons, a new forward code and inversion algorithm have been developed using the full-time decay of the induced polarization response, together with an accurate description of the transmitter waveform and of the receiver transfer function......, to reconstruct the distribution of the Cole-Cole parameters of the earth. The accurate modeling of the transmitter waveform had a strong influence on the forward response, and we showed that the difference between a solution using a step response and a solution using the accurate modeling often is above 100...

  20. Life Experience with Death: Relation to Death Attitudes and to the Use of Death-Related Memories

    Science.gov (United States)

    Bluck, Susan; Dirk, Judith; Mackay, Michael M.; Hux, Ashley

    2008-01-01

    The study examines the relation of death experience to death attitudes and to autobiographical memory use. Participants (N = 52) completed standard death attitude measures and wrote narratives about a death-related autobiographical memory and (for comparison) a memory of a low point. Self-ratings of the memory narratives were used to assess their…