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Sample records for acid cytoplasmic tail

  1. Cytoplasmic tail length influences fatty acid selection for acylation of viral glycoproteins.

    PubMed Central

    Veit, M; Reverey, H; Schmidt, M F

    1996-01-01

    We report remarkable differences in the fatty acid content of thioester-type acylated glycoproteins of enveloped viruses from mammalian cells. The E2 glycoprotein of Semliki Forest virus contains mainly palmitic acid like most other palmitoylated proteins analysed so far. However, the other glycoprotein (E1) of the same virus, as well as the HEF (haemagglutinin esterase fusion) glycoprotein of influenza C virus, are unique in this respect because they are acylated primarily with stearic acid. Comparative radiolabelling of uninfected cells with different fatty acids suggests that stearate may also be the prevailing fatty acid in some cellular acylproteins. To look for further differences between palmitoylated and stearoylated glycoproteins we characterized stearoylation in more detail. We identified the acylation site of HEF as a cysteine residue located at the boundary between the transmembrane region and the cytoplasmic tail. The attachment of stearate to HEF and E1 occurs post-translationally in a pre-Golgi compartment. Thus, stearoylated and palmitoylated proteins cannot be discriminated on the basis of the fatty acid linkage site or the intracellular compartment, where acylation occurs. However, stearoylated acylproteins contain a very short, positively charged cytoplasmic tail, whereas in palmitoylated proteins this molecular region is longer. Replacing the short cytoplasmic tail of stearoylated HEF with the long influenza A virus haemagglutinin (HA) tail in an HEF-HA chimera, and subsequent vaccinia T7 expression in CV-1 cells, yielded proteins with largely palmitic acid bound. The reverse chimera, HA-HEF with a short cytoplasmic tail was not fatty acylated at all during expression, indicating that conformational or topological constraints control fatty acid transfer. PMID:8761467

  2. Virion incorporation of envelope glycoproteins with long but not short cytoplasmic tails is blocked by specific, single amino acid substitutions in the human immunodeficiency virus type 1 matrix.

    PubMed Central

    Freed, E O; Martin, M A

    1995-01-01

    Incorporation of envelope glycoproteins into a budding retrovirus is an essential step in the formation of an infectious virus particle. By using site-directed mutagenesis, we identified specific amino acid residues in the matrix domain of the human immunodeficiency virus type 1 (HIV-1) Gag protein that are critical to the incorporation of HIV-1 envelope glycoproteins into virus particles. Pseudotyping analyses were used to demonstrate that two heterologous envelope glycoproteins with short cytoplasmic tails (the envelope of the amphotropic murine leukemia virus and a naturally truncated HIV-2 envelope) are efficiently incorporated into HIV-1 particles bearing the matrix mutations. Furthermore, deletion of the cytoplasmic tail of HIV-1 transmembrane envelope glycoprotein gp41 from 150 to 7 or 47 residues reversed the incorporation block imposed by the matrix mutations. These results suggest the existence of a specific functional interaction between the HIV-1 matrix and the gp41 cytoplasmic tail. PMID:7853546

  3. Two Cytoplasmic Acylation Sites and an Adjacent Hydrophobic Residue, but No Other Conserved Amino Acids in the Cytoplasmic Tail of HA from Influenza A Virus Are Crucial for Virus Replication.

    PubMed

    Siche, Stefanie; Brett, Katharina; Möller, Lars; Kordyukova, Larisa V; Mintaev, Ramil R; Alexeevski, Andrei V; Veit, Michael

    2015-12-01

    Recruitment of the matrix protein M1 to the assembly site of the influenza virus is thought to be mediated by interactions with the cytoplasmic tail of hemagglutinin (HA). Based on a comprehensive sequence comparison of all sequences present in the database, we analyzed the effect of mutating conserved residues in the cytosol-facing part of the transmembrane region and cytoplasmic tail of HA (A/WSN/33 (H1N1) strain) on virus replication and morphology of virions. Removal of the two cytoplasmic acylation sites and substitution of a neighboring isoleucine by glutamine prevented rescue of infectious virions. In contrast, a conservative exchange of the same isoleucine, non-conservative exchanges of glycine and glutamine, deletion of the acylation site at the end of the transmembrane region and shifting it into the tail did not affect virus morphology and had only subtle effects on virus growth and on the incorporation of M1 and Ribo-Nucleoprotein Particles (RNPs). Thus, assuming that essential amino acids are conserved between HA subtypes we suggest that, besides the two cytoplasmic acylation sites (including adjacent hydrophobic residues), no other amino acids in the cytoplasmic tail of HA are indispensable for virus assembly and budding. PMID:26670246

  4. Two Cytoplasmic Acylation Sites and an Adjacent Hydrophobic Residue, but No Other Conserved Amino Acids in the Cytoplasmic Tail of HA from Influenza A Virus Are Crucial for Virus Replication

    PubMed Central

    Siche, Stefanie; Brett, Katharina; Möller, Lars; Kordyukova, Larisa V.; Mintaev, Ramil R.; Alexeevski, Andrei V.; Veit, Michael

    2015-01-01

    Recruitment of the matrix protein M1 to the assembly site of the influenza virus is thought to be mediated by interactions with the cytoplasmic tail of hemagglutinin (HA). Based on a comprehensive sequence comparison of all sequences present in the database, we analyzed the effect of mutating conserved residues in the cytosol-facing part of the transmembrane region and cytoplasmic tail of HA (A/WSN/33 (H1N1) strain) on virus replication and morphology of virions. Removal of the two cytoplasmic acylation sites and substitution of a neighboring isoleucine by glutamine prevented rescue of infectious virions. In contrast, a conservative exchange of the same isoleucine, non-conservative exchanges of glycine and glutamine, deletion of the acylation site at the end of the transmembrane region and shifting it into the tail did not affect virus morphology and had only subtle effects on virus growth and on the incorporation of M1 and Ribo-Nucleoprotein Particles (RNPs). Thus, assuming that essential amino acids are conserved between HA subtypes we suggest that, besides the two cytoplasmic acylation sites (including adjacent hydrophobic residues), no other amino acids in the cytoplasmic tail of HA are indispensable for virus assembly and budding. PMID:26670246

  5. A structural basis for integrin activation by the cytoplasmic tail of the αIIb-subunit

    PubMed Central

    Vinogradova, Olga; Haas, Tom; Plow, Edward F.; Qin, Jun

    2000-01-01

    A key step in the activation of heterodimeric integrin adhesion receptors is the transmission of an agonist-induced cellular signal from the short α- and/or β-cytoplasmic tails to the extracellular domains of the receptor. The structural details of how the cytoplasmic tails mediate such an inside-out signaling process remain unclear. We report herein the NMR structures of a membrane-anchored cytoplasmic tail of the αIIb-subunit and of a mutant αIIb-cytoplasmic tail that renders platelet integrin αIIbβ3 constitutively active. The structure of the wild-type αIIb-cytoplasmic tail reveals a “closed” conformation where the highly conserved N-terminal membrane-proximal region forms an α-helix followed by a turn, and the acidic C-terminal loop interacts with the N-terminal helix. The structure of the active mutant is significantly different, having an “open” conformation where the interactions between the N-terminal helix and C-terminal region are abolished. Consistent with these structural differences, the two peptides differ in function: the wild-type peptide suppressed αIIbβ3 activation, whereas the mutant peptide did not. These results provide an atomic explanation for extensive biochemical/mutational data and support a conformation-based “on/off switch” model for integrin activation. PMID:10677482

  6. Modulation of cell surface transport and lipid raft localization by the cytoplasmic tail of the influenza virus hemagglutinin.

    PubMed

    Scolari, Silvia; Imkeller, Katharina; Jolmes, Fabian; Veit, Michael; Herrmann, Andreas; Schwarzer, Roland

    2016-01-01

    Viral glycoproteins are highly variable in their primary structure, but on the other hand feature a high functional conservation to fulfil their versatile tasks during the pathogenic life cycle. Typically, all protein domains are optimized in that indispensable functions can be assigned to small conserved motifs or even individual amino acids. The cytoplasmic tail of many viral spike proteins, although of particular relevance for the virus biology, is often only insufficiently characterized. Hemagglutinin (HA), the receptor-binding protein of the influenza virus comprises a short cytoplasmic tail of 13 amino acids that exhibits three highly conserved palmitoylation sites. However, the particular importance of these modifications and the tail in general for intracellular trafficking and lateral membrane organization remains elusive. In this study, we generated HA core proteins consisting of transmembrane domain, cytoplasmic tail and a minor part of the ectodomain, tagged with a yellow fluorescent protein. Different mutation and truncation variants of these chimeric proteins were investigated using confocal microscopy, to characterize the role of cytoplasmic tail and palmitoylation for the intracellular trafficking to plasma membrane and Golgi apparatus. In addition, we assessed raft partitioning of the variants by Foerster resonance energy transfer with an established raft marker. We revealed a substantial influence of the cytoplasmic tail length on the intracellular distribution and surface exposure of the proteins. A complete removal of the tail hampers a physiological trafficking of the protein, whereas a partial truncation can be compensated by cytoplasmic palmitoylations. Plasma membrane raft partitioning on the other hand was found to imperatively require palmitoylations, and the cysteine at position 551 turned out to be of most relevance. Our data shed further light on the tight interconnection between cytoplasmic elements and intracellular trafficking and

  7. Cytoplasmic Tail Regulates the Intercellular Adhesion Function of the Epithelial Cell Adhesion Molecule

    PubMed Central

    Balzar, Maarten; Bakker, Hellen A. M.; Briaire-de-Bruijn, Inge H.; Fleuren, Gert Jan; Warnaar, Sven O.; Litvinov, Sergey V.

    1998-01-01

    Ep-CAM, an epithelium-specific cell-cell adhesion molecule (CAM) not structurally related to the major families of CAMs, contains a cytoplasmic domain of 26 amino acids. The chemical disruption of the actin microfilaments, but not of the microtubuli or intermediate filaments, affected the localization of Ep-CAM at the cell-cell boundaries, suggesting that the molecule interacts with the actin-based cytoskeleton. Mutated forms of Ep-CAM were generated with the cytoplasmic domain truncated at various lengths. All of the mutants were transported to the cell surface in the transfectants; however, the mutant lacking the complete cytoplasmic domain was not able to localize to the cell-cell boundaries, in contrast to mutants with partial deletions. Both the disruption of the actin microfilaments and a complete truncation of the cytoplasmic tail strongly affected the ability of Ep-CAM to mediate aggregation of L cells. The capability of direct aggregation was reduced for the partially truncated mutants but remained cytochalasin D sensitive. The tail truncation did not affect the ability of the transfectants to adhere to solid-phase-adsorbed Ep-CAM, suggesting that the ability to form stable adhesions and not the ligand specificity of the molecule was affected by the truncation. The formation of intercellular adhesions mediated by Ep-CAM induced a redistribution to the cell-cell boundaries of α-actinin, but not of vinculin, talin, filamin, spectrin, or catenins. Coprecipitation demonstrated direct association of Ep-CAM with α-actinin. Binding of α-actinin to purified mutated and wild-type Ep-CAMs and to peptides representing different domains of the cytoplasmic tail of Ep-CAM demonstrates two binding sites for α-actinin at positions 289 to 296 and 304 to 314 of the amino acid sequence. The results demonstrate that the cytoplasmic domain of Ep-CAM regulates the adhesion function of the molecule through interaction with the actin cytoskeleton via α-actinin. PMID:9671492

  8. Cytoplasmic tail regulates the intercellular adhesion function of the epithelial cell adhesion molecule.

    PubMed

    Balzar, M; Bakker, H A; Briaire-de-Bruijn, I H; Fleuren, G J; Warnaar, S O; Litvinov, S V

    1998-08-01

    Ep-CAM, an epithelium-specific cell-cell adhesion molecule (CAM) not structurally related to the major families of CAMs, contains a cytoplasmic domain of 26 amino acids. The chemical disruption of the actin microfilaments, but not of the microtubuli or intermediate filaments, affected the localization of Ep-CAM at the cell-cell boundaries, suggesting that the molecule interacts with the actin-based cytoskeleton. Mutated forms of Ep-CAM were generated with the cytoplasmic domain truncated at various lengths. All of the mutants were transported to the cell surface in the transfectants; however, the mutant lacking the complete cytoplasmic domain was not able to localize to the cell-cell boundaries, in contrast to mutants with partial deletions. Both the disruption of the actin microfilaments and a complete truncation of the cytoplasmic tail strongly affected the ability of Ep-CAM to mediate aggregation of L cells. The capability of direct aggregation was reduced for the partially truncated mutants but remained cytochalasin D sensitive. The tail truncation did not affect the ability of the transfectants to adhere to solid-phase-adsorbed Ep-CAM, suggesting that the ability to form stable adhesions and not the ligand specificity of the molecule was affected by the truncation. The formation of intercellular adhesions mediated by Ep-CAM induced a redistribution to the cell-cell boundaries of alpha-actinin, but not of vinculin, talin, filamin, spectrin, or catenins. Coprecipitation demonstrated direct association of Ep-CAM with alpha-actinin. Binding of alpha-actinin to purified mutated and wild-type Ep-CAMs and to peptides representing different domains of the cytoplasmic tail of Ep-CAM demonstrates two binding sites for alpha-actinin at positions 289 to 296 and 304 to 314 of the amino acid sequence. The results demonstrate that the cytoplasmic domain of Ep-CAM regulates the adhesion function of the molecule through interaction with the actin cytoskeleton via alpha

  9. α integrin cytoplasmic tails have tissue-specific roles during C. elegans development

    PubMed Central

    MEIGHAN, CHRISTOPHER M.; SCHWARZBAUER, JEAN E.

    2015-01-01

    Integrin signaling impacts many developmental processes. The complexity of these signals increases when multiple, unique integrin heterodimers are expressed during a single developmental event. Since integrin heterodimers have different signaling capabilities, the signals originating at each integrin type must be separated in the cell. C. elegans have two integrin heterodimers, α INA-1/β PAT-3 and α PAT-2/β PAT-3, which are expressed individually or simultaneously, based on tissue type. We used chimeric α integrins to assess the role of α integrin cytoplasmic tails during development. Chimeric integrin ina-1 with the pat-2 cytoplasmic tail rescued lethality and maintained neuron fasciculation in an ina-1 mutant. Interestingly, the pat-2 tail was unable to completely restore distal tip cell migration and vulva morphogenesis. Chimeric integrin pat-2 with the ina-1 cytoplasmic tail had a limited ability to rescue a lethal mutation in pat-2, with survivors showing aberrant muscle organization, yet normal distal tip cell migration. In a wild type background, α integrin pat-2 with the ina-1 cytoplasmic tail had a dominant negative effect which induced muscle disorganization, cell migration defects and lethality. These results show the α integrin cytoplasmic tails impact unique cellular behaviors that vary by tissue type during development. PMID:25354452

  10. Suppression of integrin activation by the membrane-distal sequence of the integrin alphaIIb cytoplasmic tail.

    PubMed Central

    Yamanouchi, Jun; Hato, Takaaki; Tamura, Tatsushiro; Fujita, Shigeru

    2004-01-01

    Integrin cytoplasmic tails regulate integrin activation including an increase in integrin affinity for ligands. Although there is ample evidence that the membrane-proximal regions of the alpha and beta tails interact with each other to maintain integrins in a low-affinity state, little is known about the role of the membrane-distal region of the alpha tail in regulation of integrin activation. We report a critical sequence for regulation of integrin activation in the membrane-distal region of the alphaIIb tail. Alanine substitution of the RPP residues in the alphaIIb tail rendered alphaIIbbeta3 constitutively active in a metabolic energy-dependent manner. Although an alphaIIb/alpha6Abeta3 chimaeric integrin, in which the alphaIIb tail was replaced by the alpha6A tail, was in an energy-dependent active state to bind soluble ligands, introduction of the RPP sequence into the alpha6A tail inhibited binding of an activation-dependent antibody PAC1. In alphaIIb/alpha6Abeta3, deleting the TSDA sequence from the alpha6A tail or single amino acid substitutions of the TSDA residues inhibited alphaIIb/alpha6Abeta3 activation and replacing the membrane-distal region of the alphaIIb tail with TSDA rendered alphaIIbbeta3 active, suggesting a stimulatory role of TSDA in energy-dependent integrin activation. However, adding TSDA to the alphaIIb tail containing the RPP sequence of the membrane-distal region failed to activate alphaIIbbeta3. These results suggest that the RPP sequence after the GFFKR motif of the alphaIIb tail suppresses energy-dependent alphaIIbbeta3 activation. These findings provide a molecular basis for the regulation of energy-dependent integrin activation by alpha subunit tails. PMID:14723599

  11. Cytoplasmic tail domain of glycoprotein B is essential for HHV-6 infection.

    PubMed

    Mahmoud, Nora F; Jasirwan, Chyntia; Kanemoto, Satoshi; Wakata, Aika; Wang, Bochao; Hata, Yuuki; Nagamata, Satoshi; Kawabata, Akiko; Tang, Huamin; Mori, Yasuko

    2016-03-01

    Human herpesvirus 6 (HHV-6) glycoprotein B (gB) is an abundantly expressed viral glycoprotein required for viral entry and cell fusion, and is highly conserved among herpesviruses. The present study examined the function of HHV-6 gB cytoplasmic tail domain (CTD). A gB CTD deletion mutant was constructed which, in contrast to its revertant, could not be reconstituted. Moreover, deletion of gB cytoplasmic tail impaired the intracellular transport of gB protein to the trans-Golgi network (TGN). Taken together, these results suggest that gB CTD is critical for HHV-6 propagation and important for intracellular transportation. PMID:26802210

  12. The B7-1 Cytoplasmic Tail Enhances Intracellular Transport and Mammalian Cell Surface Display of Chimeric Proteins in the Absence of a Linear ER Export Motif

    PubMed Central

    Lin, Yi-Chieh; Chen, Bing-Mae; Lu, Wei-Cheng; Su, Chien-I; Prijovich, Zeljko M.; Chung, Wen-Chuan; Wu, Pei-Yu; Chen, Kai-Chuan; Lee, I-Chiao; Juan, Ting-Yi; Roffler, Steve R.

    2013-01-01

    Membrane-tethered proteins (mammalian surface display) are increasingly being used for novel therapeutic and biotechnology applications. Maximizing surface expression of chimeric proteins on mammalian cells is important for these applications. We show that the cytoplasmic domain from the B7-1 antigen, a commonly used element for mammalian surface display, can enhance the intracellular transport and surface display of chimeric proteins in a Sar1 and Rab1 dependent fashion. However, mutational, alanine scanning and deletion analysis demonstrate the absence of linear ER export motifs in the B7 cytoplasmic domain. Rather, efficient intracellular transport correlated with the presence of predicted secondary structure in the cytoplasmic tail. Examination of the cytoplasmic domains of 984 human and 782 mouse type I transmembrane proteins revealed that many previously identified ER export motifs are rarely found in the cytoplasmic tail of type I transmembrane proteins. Our results suggest that efficient intracellular transport of B7 chimeric proteins is associated with the structure rather than to the presence of a linear ER export motif in the cytoplasmic tail, and indicate that short (less than ~ 10-20 amino acids) and unstructured cytoplasmic tails should be avoided to express high levels of chimeric proteins on mammalian cells. PMID:24073236

  13. Distinct roles of NR2A and NR2B cytoplasmic tails in long term potentiation

    PubMed Central

    Foster, Kelly A.; McLaughlin, Nathan; Edbauer, Dieter; Phillips, Marnie; Bolton, Andrew; Constantine-Paton, Martha; Sheng, Morgan

    2010-01-01

    NMDA receptors (NMDARs) are critical mediators of activity-dependent synaptic plasticity, but the differential roles of NR2A- versus NR2B-containing NMDARs have been controversial. Here, we investigate the roles of NR2A and NR2B in LTP in organotypic hippocampal slice cultures using RNAi and overexpression, to complement pharmacological approaches. In young slices, when NR2B is the predominant subunit expressed, LTP is blocked by the NR2B-selective antagonist Ro25-6981. As slices mature, and NR2A expression rises, activation of NR2B receptors became no longer necessary for LTP induction. LTP was blocked, however, by RNAi knockdown of NR2B, and this was rescued by coexpression of an RNAi-resistant NR2B (NR2B*) cDNA. Interestingly, a chimeric NR2B subunit in which the C-terminal cytoplasmic tail was replaced by that of NR2A failed to rescue LTP while the reverse chimera, NR2A channel with NR2B tail, was able to restore LTP. Thus expression of NR2B with its intact cytoplasmic tail is required for LTP induction, at an age when channel activity of NR2B-NMDARs is not required for LTP. Overexpression of wildtype NR2A failed to rescue LTP in neurons transfected with NR2B-RNAi construct, despite restoring NMDA-EPSC amplitude to a similar level as NR2B*. Surprisingly, an NR2A construct lacking its entire C-terminal cytoplasmic tail regained its ability to restore LTP. Together these data suggest that the NR2B subunit plays a critical role for LTP, presumably by recruiting relevant molecules important for LTP via its cytoplasmic tail. By contrast, NR2A is not essential for LTP and its cytoplasmic tail seems to carry inhibitory factors for LTP. PMID:20164351

  14. Case 35: an unusual haematological neoplasm characterized by cells with cytoplasmic tails.

    PubMed

    Kassam, Shireen; Rice, Alexandra; Morilla, Ricardo; Bain, Barbara J

    2007-06-01

    A middle aged Northern European man presented with a submental lymph node and was found on imaging to have generalized lymphadenopathy. There was bone marrow infiltration by small apparently lymphoid cells, many with cytoplasmic tails; these cells were CD56(+) and weakly CD4(+). A provisional diagnosis was confirmed by further immunophenotyping. PMID:17577785

  15. Critical Role of the Fusion Protein Cytoplasmic Tail Sequence in Parainfluenza Virus Assembly

    PubMed Central

    Stone, Raychel; Takimoto, Toru

    2013-01-01

    Interactions between viral glycoproteins, matrix protein and nucleocapsid sustain assembly of parainfluenza viruses at the plasma membrane. Although the protein interactions required for virion formation are considered to be highly specific, virions lacking envelope glycoprotein(s) can be produced, thus the molecular interactions driving viral assembly and production are still unclear. Sendai virus (SeV) and human parainfluenza virus type 1 (hPIV1) are highly similar in structure, however, the cytoplasmic tail sequences of the envelope glycoproteins (HN and F) are relatively less conserved. To unveil the specific role of the envelope glycoproteins in viral assembly, we created chimeric SeVs whose HN (rSeVhHN) or HN and F (rSeVh(HN+F)) were replaced with those of hPIV1. rSeVhHN grew as efficiently as wt SeV or hPIV1, suggesting that the sequence difference in HN does not have a significant impact on SeV replication and virion production. In sharp contrast, the growth of rSeVh(HN+F) was significantly impaired compared to rSeVhHN. rSeVh(HN+Fstail) which expresses a chimeric hPIV1 F with the SeV cytoplasmic tail sequence grew similar to wt SeV or rSeVhHN. Further analysis indicated that the F cytoplasmic tail plays a critical role in cell surface expression/accumulation of HN and F, as well as NP and M association at the plasma membrane. Trafficking of nucelocapsids in infected cells was not significantly affected by the origin of F, suggesting that F cytoplasmic tail is not involved in intracellular movement. These results demonstrate the role of the F cytoplasmic tail in accumulation of structural components at the plasma membrane assembly sites. PMID:23593451

  16. Crystallographic characterization of the radixin FERM domain bound to the cytoplasmic tail of adhesion molecule CD44

    SciTech Connect

    Mori, Tomoyuki; Kitano, Ken; Terawaki, Shin-ichi; Maesaki, Ryoko; Hakoshima, Toshio

    2007-10-01

    The radixin FERM domain complexed with the CD44 cytoplasmic tail peptide has been crystallized. A diffraction data set from the complex was collected to 2.1 Å. CD44 is an important adhesion molecule that specifically binds hyaluronic acid and regulates cell–cell and cell–matrix interactions. Increasing evidence has indicated that CD44 is assembled in a regulated manner into the membrane–cytoskeletal junction, a process that is mediated by ERM (ezrin/radixin/moesin) proteins. Crystals of a complex between the radixin FERM domain and the C-terminal cytoplasmic region of CD44 have been obtained. The crystal of the radixin FERM domain bound to the CD44 cytoplasmic tail peptide belongs to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 62.70, b = 66.18, c = 86.22 Å, and contain one complex in the crystallographic asymmetric unit. An intensity data set was collected to a resolution of 2.1 Å.

  17. Alanine substitution of conserved residues in the cytoplasmic tail of herpes simplex virus gB can enhance or abolish cell fusion activity and viral entry

    SciTech Connect

    Ruel, Nancy . E-mail: n-ruel@northwestern.edu; Zago, Anna . E-mail: anna_zago@acgtinc.com; Spear, Patricia G. . E-mail: p-spear@northwestern.edu

    2006-03-01

    Herpes simplex virus (HSV) glycoprotein B (gB) is one of the four viral glycoproteins required for viral entry and cell fusion and is highly conserved among herpesviruses. Mutants of HSV type 2 gB were generated by substituting conserved residues in the cytoplasmic tail with alanine or by deleting 41 amino acids from the C-terminus. Some of the mutations abolished cell fusion activity and also prevented transport of gB to the cell surface, identifying residues in the gB cytoplasmic tail that are critical for intracellular transport of this glycoprotein. These mutations also prevented production of infectious virus, possibly because the mutant forms of gB were not transported to the site of envelopment. Other mutations, particularly the deletion, significantly enhanced cell fusion activity. These mutations, as well as others described previously, identify regions of the gB cytoplasmic domain that modulate cell fusion activity.

  18. A Novel Trafficking Signal within the HLA-C Cytoplasmic Tail Allows Regulated Expression Upon Differentiation of Macrophages

    PubMed Central

    Schaefer, Malinda R.; Williams, Maya; Kulpa, Deanna A.; Blakely, Pennelope K.; Yaffee, Anna Q.; Collins, Kathleen L.

    2008-01-01

    Major histocompatibility complex class I molecules (MHC-I) present peptides to cytotoxic T lymphocytes (CTLs). In addition, HLA-C allotypes are recognized by killer cell Ig-like receptors (KIR) found on natural killer (NK) cells and effector CTLs. Compared to other classical MHC-I allotypes, HLA-C has low cell surface expression and an altered intracellular trafficking pattern. We present evidence that this results from effects of both the extracellular domain and the cytoplasmic tail. Notably, we demonstrate that the cytoplasmic tail contains a dihydrophobic (LI) internalization and lysosomal targeting signal that is partially attenuated by an aspartic acid residue (DXSLI). In addition, we provide evidence that this signal is specifically inhibited by hypophosphorylation of the adjacent serine residue upon macrophage differentiation and that this allows high HLA-C expression in this cell type. We propose that tightly regulated HLA-C surface expression facilitates immune surveillance and allows HLA-C to serve a specialized role in macrophages. PMID:18523244

  19. The Cytoplasmic Tail Domain of Influenza B Virus Hemagglutinin Is Important for Its Incorporation into Virions but Is Not Essential for Virus Replication in Cell Culture in the Presence of Compensatory Mutations

    PubMed Central

    Watanabe, Shinji

    2012-01-01

    Influenza B virus hemagglutinin (BHA) contains a predicted cytoplasmic tail of 10 amino acids that are highly conserved among influenza B viruses. To understand the role of this cytoplasmic tail in infectious virus production, we used reverse genetics to generate a recombinant influenza B virus lacking the BHA cytoplasmic tail domain. The resulting virus, designated BHATail−, had a titer approximately 5 log units lower than that of wild-type virus but grew normally when BHA was supplemented in trans by BHA-expressing cells. Although the levels of BHA cell surface expression were indistinguishable between truncated and wild-type BHA, the BHATail− virus produced particles containing dramatically less BHA. Moreover, removal of the cytoplasmic tail abrogated the association of BHA with Triton X-100-insoluble lipid rafts. Interestingly, long-term culture of a virus lacking the BHA cytoplasmic tail in Madin-Darby canine kidney (MDCK) cells yielded a mutant with infectivities somewhat similar to that of wild-type virus. Sequencing revealed that the mutant virus retained the original cytoplasmic tail deletion but acquired additional mutations in its BHA, neuraminidase (NA), and M1 proteins. Viral growth kinetic analysis showed that replication of BHA cytoplasmic tailless viruses could be improved by compensatory mutations in the NA and M1 proteins. These findings indicate that the cytoplasmic tail domain of BHA is important for efficient incorporation of BHA into virions and tight lipid raft association. They also demonstrate that the domain is not absolutely required for virus viability in cell culture in the presence of compensatory mutations. PMID:22896616

  20. The cleaved cytoplasmic tail of polycystin-1 regulates Src-dependent STAT3 activation.

    PubMed

    Talbot, Jeffrey J; Song, Xuewen; Wang, Xiaofang; Rinschen, Markus M; Doerr, Nicholas; LaRiviere, Wells B; Schermer, Bernhard; Pei, York P; Torres, Vicente E; Weimbs, Thomas

    2014-08-01

    Polycystin-1 (PC1) mutations result in proliferative renal cyst growth and progression to renal failure in autosomal dominant polycystic kidney disease (ADPKD). The transcription factor STAT3 (signal transducer and activator of transcription 3) was shown to be activated in cyst-lining cells in ADPKD and PKD mouse models and may drive renal cyst growth, but the mechanisms leading to persistent STAT3 activation are unknown. A proteolytic fragment of PC1 corresponding to the cytoplasmic tail, PC1-p30, is overexpressed in ADPKD. Here, we show that PC1-p30 interacts with the nonreceptor tyrosine kinase Src, resulting in Src-dependent activation of STAT3 by tyrosine phosphorylation. The PC1-p30-mediated activation of Src/STAT3 was independent of JAK family kinases and insensitive to the STAT3 inhibitor suppressor of cytokine signaling 3. Signaling by the EGF receptor (EGFR) or cAMP amplified the activation of Src/STAT3 by PC1-p30. Expression of PC1-p30 changed the cellular response to cAMP signaling. In the absence of PC1-p30, cAMP dampened EGFR- or IL-6-dependent activation of STAT3; in the presence of PC1-p30, cAMP amplified Src-dependent activation of STAT3. In the polycystic kidney (PCK) rat model, activation of STAT3 in renal cystic cells depended on vasopressin receptor 2 (V2R) signaling, which increased cAMP levels. Genetic inhibition of vasopressin expression or treatment with a pharmacologic V2R inhibitor strongly suppressed STAT3 activation and reduced renal cyst growth. These results suggest that PC1, via its cleaved cytoplasmic tail, integrates signaling inputs from EGFR and cAMP, resulting in Src-dependent activation of STAT3 and a proliferative response. PMID:24578126

  1. Cytoplasmic tail of IL-13Ralpha2 regulates IL-4 signal transduction.

    PubMed

    Andrews, Allison-Lynn; Nordgren, Ida Karin; Kirby, Isabelle; Holloway, John W; Holgate, Stephen T; Davies, Donna E; Tavassoli, Ali

    2009-08-01

    IL (interleukin)-4 and IL-13 are key cytokines in the pathogenesis of allergic inflammatory disease. IL-4 and IL-13 share many functional properties as a result of their utilization of a common receptor complex comprising IL-13Ralpha1 (IL-13 receptor alpha-chain 1) and IL-4Ralpha. The second IL-13R (IL-13 receptor) has been identified, namely IL-13Ralpha2. This has been thought to be a decoy receptor due to its short cytoplasmic tail and its high binding affinity for IL-13 but not IL-4. IL-13Ralpha2 exists on the cell membrane, intracellularly and in a soluble form. Recent reports revealed that membrane IL-13Ralpha2 may have some signalling capabilities, and a soluble form of IL-13Ralpha2 can be generated in the presence of environmental allergens such as DerP. Interestingly, IL-13Ralpha2 has also been shown to regulate both IL-13 and IL-4 response in primary airway cells, despite the fact that IL-13Ralpha2 does not bind IL-4. The regulator mechanism is still unclear but the physical association of IL-13Ralpha2 with IL-4Ralpha appears to be a key regulatory step. These results suggest that the cytoplasmic tail of IL-13Ralpha2 may interfere with the association or activation of signalling molecules, such as JAK1 (Janus kinase 1), on IL-4Ralpha and thus prevents downstream signal cascade. The receptor has more complicated functions than a simple decoy receptor. In this review, we discuss newly revealed functions of IL-13Ralpha2. PMID:19614610

  2. Skeletal Phenotype of Transgenic Mice Expressing the Beta1 Integrin Cytoplasmic Tail In Osteoblasts

    NASA Technical Reports Server (NTRS)

    Globus, R. K.; vanderMeulen, M. C. H.; Damsky, D.; Kim, J.-B.; Amblard, D.; Amblard, D.; Nishimura, Y.; Almeida, E.; Iwaniec, U. T.; Wronski, T. J.; Dalton, Bonnie (Technical Monitor)

    2002-01-01

    To define the physiologic role of beta1 integrin in bone formation and mechanical loading, transgenic mice were generated by expressing the cytoplasmic tall and transmembrane domain of Beta1 integrin under the control of the osteocalcin promoter. In cultured cells, this truncated fragment of Beta1 can act as a dominant negative. Previously, the matrix of calvariae was shown to be abnormal in transgenic (TG) compared to wildtype (WT) mice. In this study, we analyzed appendicular bone in TG and WT, male and female mice at 14, 35, 63, 90 and 365 days old (n=8-12/gp). To assess beta1 integrin function in mechanical loading, a pilot study using hindlimb unloading by tail suspension was performed. 35d old TG and WT females were hindlimb unloaded for 4 wks (n=3-5). Body mass, bone mineral content, histomorphometric (distal femur) and biomechanical parameters were analyzed. Statistical significance (P less than.05) was defined by ANOVA using the Tukey-Kramer post-hoc test. We confirmed transgene expression by immunoprecipitating then immunoblotting bone lysates using an antibody against the beta1 tail. Body masses of TG mice at 63, 90 and 365d old were greater (16-25%) than WT. Some TG female mice at 365d appeared obese; mean abdominal fat mass was 415% greater in TG than WT mice. Tibiae were longer (5-7%) in TG than WT mice at 63 and 90d. Tibial mineral mass of 35d males was 7% lower in TG than WT mice, but at 63d was 21% higher. The % osteoblast surface in 35d TG mice was 20% higher than WT, and at 63d was 17% lower, while % osteoclast surface did not differ. In 365d mice, cancellous bone volume (125%) and endocortical mineral apposition rate (40%) were greater in TG than WT males but not females. In WT mice, hindlimb unloading caused a reduction in mineral mass of tibiae (-20%) and lumbar vertebrae (-22%) relative to normally loaded controls. Surprisingly, hindlimb unloading also caused a relative reduction (-13%) in humerus mass. The effects of hindlimb unloading on

  3. Endocytosis via coated pits mediated by glycoprotein receptor in which the cytoplasmic tail is replaced by unrelated sequences.

    PubMed Central

    Verrey, F; Gilbert, T; Mellow, T; Proulx, G; Drickamer, K

    1990-01-01

    Rat 6 fibroblast cell lines expressing wild-type chicken liver glycoprotein receptor (CHL) or chimeric receptors with alternate cytoplasmic tails were produced to study the role of the cytoplasmic tail in mediating receptor localization in coated pits and endocytosis of ligand. Cells expressing CHL or cells expressing a hybrid receptor that contains the cytoplasmic tail of the asialoglycoprotein receptor display high-efficiency endocytosis of N-acetylglucosamine-conjugated bovine serum albumin in experiments designed to measure an initial internalization step, as well as in studies of continuous uptake and degradation. Substitution of the cytoplasmic tail by the equivalent domain of rat Na,K-ATPase beta subunit or by a stretch of Xenopus laevis globin beta chain does not abolish endocytosis but decreases the endocytosis rate constant from 15%-16%/min to 2.4% and 6.5%/min, respectively. Electron microscopy was used to visualize the glycoprotein binding sites at the surface of Rat 6 cells transfected with the various receptors. The percentage of receptors found in coated areas ranged from 32% for CHL to 9% for the Na,K-ATPase hybrid, indicating that clustering in coated pits correlates with efficiency of endocytosis. We concluded that replacement of the CHL cytoplasmic tail with unrelated sequences does not prevent, but decreases to varying extents, coated-pit localization and endocytosis efficiency. The construct with NH2-terminal globin tail lacks a signal for high-efficiency localization in coated pits but nevertheless is directed to the pits by an alternative mechanism. Images PMID:1963794

  4. Integrin α1 Has a Long Helix, Extending from the Transmembrane Region to the Cytoplasmic Tail in Detergent Micelles

    PubMed Central

    Lai, Chaohua; Liu, Xiaoxi; Tian, Changlin; Wu, Fangming

    2013-01-01

    Integrin proteins are very important adhesion receptors that mediate cell-cell and cell-extracellular matrix interactions. They play essential roles in cell signaling and the regulation of cellular shape, motility, and the cell cycle. Here, the transmembrane and cytoplasmic (TMC) domains of integrin α1 and β1 were over-expressed and purified in detergent micelles. The structure and backbone relaxations of α1-TMC in LDAO micelles were determined and analyzed using solution NMR. A long helix, extending from the transmembrane region to the cytoplasmic tail, was observed in α1-TMC. Structural comparisons of α1-TMC with reported αIIb-TMC domains indicated different conformations in the transmembrane regions and cytoplasmic tails. An NMR titration experiment indicated weak interactions between α1-TMC and β1-TMC through several α1-TMC residues located at its N-terminal juxta-transmembrane region and C-terminal extended helix region. PMID:23646163

  5. Polybasic KKR Motif in the Cytoplasmic Tail of Nipah Virus Fusion Protein Modulates Membrane Fusion by Inside-Out Signaling▿

    PubMed Central

    Aguilar, Hector C.; Matreyek, Kenneth A.; Choi, Daniel Y.; Filone, Claire Marie; Young, Sophia; Lee, Benhur

    2007-01-01

    The cytoplasmic tails of the envelope proteins from multiple viruses are known to contain determinants that affect their fusogenic capacities. Here we report that specific residues in the cytoplasmic tail of the Nipah virus fusion protein (NiV-F) modulate its fusogenic activity. Truncation of the cytoplasmic tail of NiV-F greatly inhibited cell-cell fusion. Deletion and alanine scan analysis identified a tribasic KKR motif in the membrane-adjacent region as important for modulating cell-cell fusion. The K1A mutation increased fusion 5.5-fold, while the K2A and R3A mutations decreased fusion 3- to 5-fold. These results were corroborated in a reverse-pseudotyped viral entry assay, where receptor-pseudotyped reporter virus was used to infect cells expressing wild-type or mutant NiV envelope glycoproteins. Differential monoclonal antibody binding data indicated that hyper- or hypofusogenic mutations in the KKR motif affected the ectodomain conformation of NiV-F, which in turn resulted in faster or slower six-helix bundle formation, respectively. However, we also present evidence that the hypofusogenic phenotypes of the K2A and R3A mutants were effected via distinct mechanisms. Interestingly, the K2A mutant was also markedly excluded from lipid rafts, where ∼20% of wild-type F and the other mutants can be found. Finally, we found a strong negative correlation between the relative fusogenic capacities of these cytoplasmic-tail mutants and the avidities of NiV-F and NiV-G interactions (P = 0.007, r2 = 0.82). In toto, our data suggest that inside-out signaling by specific residues in the cytoplasmic tail of NiV-F can modulate its fusogenicity by multiple distinct mechanisms. PMID:17301148

  6. The Nectin-1α Transmembrane Domain, But Not The Cytoplasmic Tail, Influences Cell Fusion Induced by HSV-1 Glycoproteins

    PubMed Central

    Subramanian, Ravi P.; Dunn, Jennifer E.; Geraghty, Robert J.

    2006-01-01

    Nectin-1 is a receptor for herpes simplex virus (HSV), a member of the immunoglobulin superfamily, and a cellular adhesion molecule. To study domains of nectin-1α involved in cell fusion, we measured the ability of nectin-1α/nectin-2α chimeras, nectin-1α/CD4 chimeras, and transmembrane domain and cytoplasmic tail mutants of nectin-1α to promote cell fusion induced by HSV-1 glycoproteins. Our results demonstrate that only chimeras and mutants containing the entire V-like domain and a link to the plasma membrane conferred cell-fusion activity. The transmembrane domain and cytoplasmic tail of nectin-1 were not required for any viral receptor or cell adhesion function tested. Cellular cytoplasmic factors that bind to the nectin-1α cytoplasmic tail, therefore, did not influence virus entry or cell fusion. Interestingly, the efficiency of cell fusion was reduced when membrane spanning domains of nectin-1α and gD were replaced by glycosylphosphatidylinositol tethers, indicating that transmembrane domains may play a modulatory role in the gD/nectin-1α interaction in fusion. PMID:16005040

  7. The nectin-1{alpha} transmembrane domain, but not the cytoplasmic tail, influences cell fusion induced by HSV-1 glycoproteins

    SciTech Connect

    Subramanian, Ravi P.; Dunn, Jennifer E.; Geraghty, Robert J. . E-mail: rgeragh@uky.edu

    2005-09-01

    Nectin-1 is a receptor for herpes simplex virus (HSV), a member of the immunoglobulin superfamily, and a cellular adhesion molecule. To study domains of nectin-1{alpha} involved in cell fusion, we measured the ability of nectin-1{alpha}/nectin-2{alpha} chimeras, nectin-1{alpha}/CD4 chimeras, and transmembrane domain and cytoplasmic tail mutants of nectin-1{alpha} to promote cell fusion induced by HSV-1 glycoproteins. Our results demonstrate that only chimeras and mutants containing the entire V-like domain and a link to the plasma membrane conferred cell-fusion activity. The transmembrane domain and cytoplasmic tail of nectin-1 were not required for any viral receptor or cell adhesion function tested. Cellular cytoplasmic factors that bind to the nectin-1{alpha} cytoplasmic tail, therefore, did not influence virus entry or cell fusion. Interestingly, the efficiency of cell fusion was reduced when membrane-spanning domains of nectin-1{alpha} and gD were replaced by glycosylphosphatidylinositol tethers, indicating that transmembrane domains may play a modulatory role in the gD/nectin-1{alpha} interaction in fusion.

  8. Membrane-Mediated Regulation of the Intrinsically Disordered CD3ϵ Cytoplasmic Tail of the TCR

    PubMed Central

    López, Cesar A.; Sethi, Anurag; Goldstein, Byron; Wilson, Bridget S.; Gnanakaran, S.

    2015-01-01

    The regulation of T-cell-mediated immune responses depends on the phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) on T-cell receptors. Although many details of the signaling cascades are well understood, the initial mechanism and regulation of ITAM phosphorylation remains unknown. We used molecular dynamics simulations to study the influence of different compositions of lipid bilayers on the membrane association of the CD3ϵ cytoplasmic tails of the T-cell receptors. Our results show that binding of CD3ϵ to membranes is modulated by both the presence of negatively charged lipids and the lipid order of the membrane. Free-energy calculations reveal that the protein-membrane interaction is favored by the presence of nearby basic residues and the ITAM tyrosines. Phosphorylation minimizes membrane association, rendering the ITAM motif more accessible to binding partners. In systems mimicking biological membranes, the CD3ϵ chain localization is modulated by different facilitator lipids (e.g., gangliosides or phosphoinositols), revealing a plausible regulatory effect on activation through the regulation of lipid composition in cell membranes. PMID:25992726

  9. The p55 tumour necrosis factor receptor TNFR1 contains a trans-Golgi network localization signal in the C-terminal region of its cytoplasmic tail.

    PubMed Central

    Storey, Helen; Stewart, Abigail; Vandenabeele, Peter; Luzio, J Paul

    2002-01-01

    It has been reported in some human cells that, in addition to a plasma membrane localization, members of the tumour necrosis factor receptor superfamily may be localized to the Golgi complex. We have shown by immunofluorescence and immunoelectron microscopy that the p55 tumour necrosis factor receptor, TNFR1, is principally localized to the trans-Golgi network in the human breast carcinoma cell line, MCF7. Chimaeras consisting of the extracellular and transmembrane domains of CD8 together with the cytoplasmic tail of TNFR1 were targeted to the trans-Golgi network in stably transfected rat fibroblastic cells. Deletions in the cytoplasmic tails of these chimaeras demonstrated the requirement for the C-terminal sequence of 23 amino acids for this targeting. The 23 amino acid sequence is mostly outside the death domain and contains both an acid patch and a dileucine motif. Interaction of this sequence with membrane traffic adaptor proteins may play an important role in controlling the responses of cells to tumour necrosis factor, since binding of signalling adaptor proteins has only been demonstrated for plasma membrane, and not Golgi-localized, TNFR1. PMID:11985495

  10. Structures and Interaction Analyses of Integrin αMβ2 Cytoplasmic Tails*

    PubMed Central

    Chua, Geok-Lin; Tang, Xiao-Yan; Amalraj, Monalisa; Tan, Suet-Mien; Bhattacharjya, Surajit

    2011-01-01

    Integrins are heterodimeric (α and β subunits) signal transducer proteins involved in cell adhesions and migrations. The cytosolic tails of integrins are essential for transmitting bidirectional signaling and also implicated in maintaining the resting states of the receptors. In addition, cytosolic tails of integrins often undergo post-translation modifications like phosphorylation. However, the consequences of phosphorylation on the structures and interactions are not clear. The leukocyte-specific integrin αMβ2 is essential for myeloid cell adhesion, phagocytosis, and degranulation. In this work, we determined solution structures of the myristoylated cytosolic tail of αM and a Ser phosphorylated variant in dodecylphosphocholine micelles by NMR spectroscopy. Furthermore, the interactions between non-phosphorylated and phosphorylated αM tails with β2 tail were investigated by NMR and fluorescence resonance energy transfer (FRET). The three-dimensional structures of the 24-residue cytosolic tail of αM or phosphorylated αM are characterized by an N-terminal amphipathic helix and a loop at the C terminus. The residues at the loop are involved in packing interactions with the hydrophobic face of the helix. 15N-1H heteronuclear single quantum coherence experiments identified residues of αM and β2 tails that may be involved in the formation of a tail-tail heterocomplex. We further examined interactions between myristoylated β2 tail in dodecylphosphocholine micelles with dansylated αM tail peptides by FRET. These studies revealed enhanced interactions between αM or phosphorylated αM tails with β2 tail with Kd values ∼5.2 ± 0.6 and ∼4.4 ± 0.7 μm, respectively. Docked structures of tail-tail complexes delineated that the αM/β2 interface at the cytosolic region could be sustained by a network of polar interactions, ionic interactions, and/or hydrogen bonds. PMID:22052909

  11. Membrane fusion by the GTPase atlastin requires a conserved C-terminal cytoplasmic tail and dimerization through the middle domain

    PubMed Central

    Moss, Tyler J.; Andreazza, Camilla; Verma, Avani; Daga, Andrea; McNew, James A.

    2011-01-01

    The biogenesis and maintenance of the endoplasmic reticulum (ER) requires membrane fusion. ER homotypic fusion is driven by the large GTPase atlastin. Domain analysis of atlastin shows that a conserved region of the C-terminal cytoplasmic tail is absolutely required for fusion activity. Atlastin in adjacent membranes must associate to bring the ER membranes into molecular contact. Drosophila atlastin dimerizes in the presence of GTPγS but is monomeric with GDP or without nucleotide. Oligomerization requires the juxtamembrane middle domain three-helix bundle, as does efficient GTPase activity. A soluble version of the N-terminal cytoplasmic domain that contains the GTPase domain and the middle domain three-helix bundle serves as a potent, concentration-dependent inhibitor of membrane fusion both in vitro and in vivo. However, atlastin domains lacking the middle domain are without effect. GTP-dependent dimerization of atlastin generates an enzymatically active protein that drives membrane fusion after nucleotide hydrolysis and conformational reorganization. PMID:21690399

  12. Coupling of Human Immunodeficiency Virus Type 1 Fusion to Virion Maturation: a Novel Role of the gp41 Cytoplasmic Tail

    PubMed Central

    Wyma, Donald J.; Jiang, Jiyang; Shi, Jiong; Zhou, Jing; Lineberger, Janet E.; Miller, Michael D.; Aiken, Christopher

    2004-01-01

    Retrovirus particles are not infectious until they undergo proteolytic maturation to form a functional core. Here we report a link between human immunodeficiency virus type 1 (HIV-1) core maturation and the ability of the virus to fuse with target cells. Using a recently developed reporter assay of HIV-1 virus-cell fusion, we show that immature HIV-1 particles are 5- to 10-fold less active for fusion with target cells than are mature virions. The fusion of mature and immature virions was rendered equivalent by truncating the gp41 cytoplasmic domain or by pseudotyping viruses with the glycoprotein of vesicular stomatitis virus. An analysis of a panel of mutants containing mutated cleavage sites indicated that HIV-1 fusion competence is activated by the cleavage of Gag at any site between the MA and NC segments and not as an indirect consequence of an altered core structure. These results suggest a mechanism by which binding of the gp41 cytoplasmic tail to Gag within immature HIV-1 particles inhibits Env conformational changes on the surface of the virion that are required for membrane fusion. This “inside-out” regulation of HIV-1 fusion could play an important role in the virus life cycle by preventing the entry of immature, noninfectious particles. PMID:15016865

  13. The Fn14 cytoplasmic tail binds tumour-necrosis-factor-receptor-associated factors 1, 2, 3 and 5 and mediates nuclear factor-kappaB activation.

    PubMed Central

    Brown, Sharron A N; Richards, Christine M; Hanscom, Heather N; Feng, Sheau-Line Y; Winkles, Jeffrey A

    2003-01-01

    Fn14 is a growth-factor-inducible immediate-early-response gene encoding a 102-amino-acid type I transmembrane protein. The human Fn14 protein was recently identified as a cell-surface receptor for the tumour necrosis factor (TNF) superfamily member named TWEAK (TNF-like weak inducer of apoptosis). In the present paper, we report that the human TWEAK extracellular domain can also bind the murine Fn14 protein. Furthermore, site-specific mutagenesis and directed yeast two-hybrid interaction assays revealed that the TNFR-associated factor (TRAF) 1, 2, 3 and 5 adaptor molecules bind the murine Fn14 cytoplasmic tail at an overlapping, but non-identical, amino acid sequence motif. We also found that TWEAK treatment of quiescent NIH 3T3 cells stimulates inhibitory kappaBalpha phosphorylation and transcriptional activation of a nuclear factor-kappaB (NF-kappaB) enhancer/luciferase reporter construct. Fn14 overexpression in transiently transfected NIH 3T3 cells also promotes NF-kappaB activation, and this cellular response requires an intact TRAF binding site. These results indicate that Fn14 is a functional TWEAK receptor that can associate with four distinct TRAF family members and stimulate the NF-kappaB transcription factor signalling pathway. PMID:12529173

  14. Surface Exposure of the HIV-1 Env Cytoplasmic Tail LLP2 Domain during the Membrane Fusion Process

    PubMed Central

    Lu, Lu; Zhu, Yun; Huang, Jinghe; Chen, Xi; Yang, Hengwen; Jiang, Shibo; Chen, Ying-Hua

    2008-01-01

    HIV-1 gp41 cytoplasmic tail (CT) is highly conserved among HIV-1 isolates, particularly the region designated lentivirus lytic peptide (LLP1–2), which includes two α-helical domains LLP1 and LLP2. Although the gp41 CT is recognized as a modulator of viral fusogenicity, little is known about the regulatory mechanism of this region in the viral fusion process. Here we report that anti-LLP1–2 and anti-LLP2 antibodies (IgG) inhibited HIV-1 Env-mediated cell fusion and bound to the interface between effector and target cells at a suboptimal temperature (31.5 °C), which slows down the fusion process and prolongs the fusion intermediate state. This suggests that LLP1–2, especially the LLP2 region located inside the viral membrane, is transiently exposed on the membrane surface during the fusion process. Synthetic LLP2 peptide could bind to the gp41 six-helix bundle core with high binding affinity. These results suggest that the gp41 CT may interact with the gp41 core, via the surface-exposed LLP2 domain, to regulate Env-mediated membrane fusion. PMID:18408000

  15. The Genes for Cytoplasmic Ribosomal Ribonucleic Acid in Higher Plants

    PubMed Central

    Scott, N. Steele; Ingle, J.

    1973-01-01

    The genes for cytoplasmic ribosomal RNA are partially resolved from the bulk of the DNA by CsCl equilibrium centrifugation. Although in some plants the buoyant density of the ribosomal RNA genes is as expected from the base composition of ribosomal RNA, others show a large discrepancy which cannot be due to the presence of low G-C spacer-DNA. The cross-hybridization observed with 1.3 and 0.7 × 106 molecular weight ribosomal RNAs and DNA, which varies greatly with different plant species, is not due to contamination of the ribosomal RNAs, and is specific for the ribosomal DNA of each species, probably largely restricted to those sequences coding for the two stable ribosomal RNAs. The double reciprocal plot may be used for the extrapolation of saturation values only with caution, because in these cases such plots are not linear over the whole of the hybridization reaction. PMID:16658392

  16. The putative invertebrate adaptive immune protein Litopenaeus vannamei Dscam (LvDscam) is the first reported Dscam to lack a transmembrane domain and cytoplasmic tail.

    PubMed

    Chou, Pin-Hsiang; Chang, Hao-Shuo; Chen, I-Tung; Lin, Han-You; Chen, Yi-Min; Yang, Huey-Lang; Wang, K C Han-Ching

    2009-12-01

    It has recently been suggested that Dscam (Down syndrome cell adhesion molecule), a member of the immunoglobulin superfamily (IgSF), plays an essential role in the alternative adaptive immune system of invertebrates. Here, we isolated and characterized the first shrimp Dscam from Litopenaeus vannamei. The LvDscam protein had an extracellular domain but lacked the expected transmembrane domain and cytoplasmic tail, both of which are found in all other members of the Dscam family (and may also be found in other L. vannamei Dscams that have not yet been isolated). In nervous tissue, expression levels of LvDscam were unexpectedly low. Phylogenetic analysis suggests that LvDscam is far from the Dscams found in other invertebrates. Nevertheless, the domain architecture of the extracellular region of LvDscam is similar to other invertebrate Dscams, and it exhibits the typical configuration of 10 immunoglobulin (Ig) domains, 6 fibronectin type 3 domains (FNIII) and one cell attachment sequence (RGD). Cloning and characterization of a total of 62 cDNAs from hemocytes collected from WSSV-free, WSSV-persistent and WSSV-acute-infected shrimp revealed 23 alternative amino acid sequences in the N-terminal of Ig2, 30 in the N-terminal of Ig3 and 13 in the Ig7 domain. This implies that LvDscam can potentially encode at least 8970 unique isoforms. Further analysis suggested that the LvDscam Ig2 and Ig3 regions are more functionally important than Ig7 in the shrimp's specific immune response against WSSV. We discuss how this tail-less, soluble Dscam can still play an active role in alternative adaptive immune response even while its axonal guidance functionality may be impaired. PMID:19635499

  17. Revegetation potential of acidic mill tailings in southwestern New Mexico

    SciTech Connect

    Cornelius, J.M.; Beeson, D.L.; Gomez, M.; Lindemann, W.C.; Whitford, W.G.; Zehner, W.B.

    1995-12-31

    A greenhouse project was conducted to examine the revegetation potential of acid mill tailings from an abandoned mill site near Silver City, Grant County, New Mexico. The tailings piles covered about 35 acres, had percent level concentrations of Zn, Cu, Pb, an average pH of 2.2, and an average net neutralization potential of 120 tons calcium carbonate per kiloton tailings. To successfully revegetate the tailings, five problems must be overcome: (1) neutralization of current and future acidity, (2) immobilization of metals, (3) restoration of biological activity, (4) improvement of water holding capacity, and (5) increasing the supply of plant nutrients. Tailings material was mixed with crushed limestone and divided into greenhouse pots in a randomized complete block design with factorial arrangement of treatments, including nine plant species and four organic amendments. Fertilizer was added based on soil fertility analysis. Germination and growth characteristics of plant species, and physical and chemical characteristics of soil were examined. Liming effectively removed or moderated most chemical plant growth problems. Water soluble and plant available metals in neutralized tailings were slightly higher than in native soils.

  18. Day-to-night variations of cytoplasmic pH in a crassulacean acid metabolism plant.

    PubMed

    Hafke, J B; Neff, R; Hütt, M T; Lüttge, U; Thiel, G

    2001-01-01

    In crassulacean acid metabolism (CAM) large amounts of malic acid are redistributed between vacuole and cytoplasm in the course of night-to-day transitions. The corresponding changes of the cytoplasmic pH (pHcyt) were monitored in mesophyll protoplasts from the CAM plant Kalanchoe daigremontiana Hamet et Perrier by ratiometric fluorimetry with the fluorescent dye 2',7'-bis-(2-carboxyethyl)-5-(and-6-)carboxyfluorescein as a pHcyt indicator. At the beginning of the light phase, pHcyt was slightly alkaline (about 7.5). It dropped during midday by about 0.3 pH units before recovering again in the late-day-to-early-dark phase. In the physiological context the variation in pHcyt may be a component of CAM regulation. Due to its pH sensitivity, phosphoenolpyruvate carboxylase appears as a likely target enzyme. From monitoring delta pHcyt in response to loading the cytoplasm with the weak acid salt K-acetate a cytoplasmic H(+)-buffer capacity in the order of 65 mM H+ per pH unit was estimated at a pHcyt of about 7.5. With this value, an acid load of the cytoplasm by about 10 mM malic acid can be estimated as the cause of the observed drop in pHcyt. A diurnal oscillation in pHcyt and a quantitatively similar cytoplasmic malic acid is predicted from an established mathematical model which allows simulation of the CAM dynamics. The similarity of model predictions and experimental data supports the view put forward in this model that a phase transition of the tonoplast is an essential functional element in CAM dynamics. PMID:11732184

  19. Membrane structure correlates to function of LLP2 on the cytoplasmic tail of HIV-1 gp41 protein.

    PubMed

    Boscia, Alexander L; Akabori, Kiyotaka; Benamram, Zachary; Michel, Jonathan A; Jablin, Michael S; Steckbeck, Jonathan D; Montelaro, Ronald C; Nagle, John F; Tristram-Nagle, Stephanie

    2013-08-01

    Mutation studies previously showed that the lentivirus lytic peptide (LLP2) sequence of the cytoplasmic C-terminal tail of the HIV-1 gp41 envelope protein inhibited viral-initiated T-cell death and T-cell syncytium formation, at which time in the HIV life cycle the gp41 protein is embedded in the T-cell membrane. In striking contrast, the mutants did not affect virion infectivity, during which time the gp41 protein is embedded in the HIV envelope membrane. To examine the role of LLP2/membrane interactions, we applied synchrotron x-radiation to determine structure of hydrated membranes. We focused on WT LLP2 peptide (+3 charge) and MX2 mutant (-1 charge) with membrane mimics for the T-cell and the HIV-1 membranes. To investigate the influence of electrostatics, cholesterol content, and peptide palmitoylation, we also studied three other LLP2 variants and HIV-1 mimics without negatively charged lipids or cholesterol as well as extracted HIV-1 lipids. All LLP2 peptides bound strongly to T-cell membrane mimics, as indicated by changes in membrane structure and bending. In contrast, none of the weakly bound LLP2 variants changed the HIV-1 membrane mimic structure or properties. This correlates well with, and provides a biophysical basis for, previously published results that reported lack of a mutant effect in HIV virion infectivity in contrast to an inhibitory effect in T-cell syncytium formation. It shows that interaction of LLP2 with the T-cell membrane modulates biological function. PMID:23931314

  20. Neutralization resistance of virological synapse-mediated HIV-1 Infection is regulated by the gp41 cytoplasmic tail.

    PubMed

    Durham, Natasha D; Yewdall, Alice W; Chen, Ping; Lee, Rebecca; Zony, Chati; Robinson, James E; Chen, Benjamin K

    2012-07-01

    Human immunodeficiency virus type 1 (HIV-1) infection can spread efficiently from infected to uninfected T cells through adhesive contacts called virological synapses (VSs). In this process, cell-surface envelope glycoprotein (Env) initiates adhesion and viral transfer into an uninfected recipient cell. Previous studies have found some HIV-1-neutralizing patient sera to be less effective at blocking VS-mediated infection than infection with cell-free virus. Here we employ sensitive flow cytometry-based infection assays to measure the inhibitory potency of HIV-1-neutralizing monoclonal antibodies (MAb) and HIV-1-neutralizing patient sera against cell-free and VS-mediated infection. To various degrees, anti-Env MAbs exhibited significantly higher 50% inhibitory concentration (IC(50)s) against VS-mediated infection than cell-free infection. Notably, the MAb 17b, which binds a CD4-induced (CD4i) epitope on gp120, displayed a 72-fold reduced efficacy against VS-mediated inocula compared to cell-free inocula. A mutant with truncation mutation in the gp41 cytoplasmic tail (CT) which is unable to modulate Env fusogenicity in response to virus particle maturation but which can still engage in cell-to-cell infection was tested for the ability to resist neutralizing antibodies. The ΔCT mutation increased cell surface staining by neutralizing antibodies, significantly enhanced neutralization of VS-mediated infection, and had reduced or no effect on cell-free infection, depending upon the antibody. Our results suggest that the gp41 CT regulates the exposure of key neutralizing epitopes during cell-to-cell infection and plays an important role in immune evasion. Vaccine strategies should consider immunogens that reflect Env conformations exposed on the infected cell surface to enhance protection against VS-mediated HIV-1 spread. PMID:22553332

  1. Infection of human and non-human cells by a highly fusogenic primary CD4-independent HIV-1 isolate with a truncated envelope cytoplasmic tail

    SciTech Connect

    Saha, Kunal . E-mail: sahak@pediatrics.ohio-state.edu; Yan Hui; Nelson, Julie A.E.; Zerhouni-Layachi, Bouchra

    2005-06-20

    Truncation of the envelope cytoplasmic tail has enabled FIV, SIV, and some laboratory HIV-1 strains to acquire broader cellular tropism and enhanced fusogenicity. Here we have characterized a primary CD4-independent HIV-1 isolate (92UG046-T8) with a truncated cytoplasmic tail that was able to infect and induce syncytia in primary lymphocytes from human, chimpanzee, and monkey, as well as CD4-negative cell lines from human and monkey. Increased syncytia were also noticeable with 293 cells expressing the cloned envelope from the 92UG046-T8 isolate suggesting envelope-mediated cellular fusion. Except pooled serum from HIV-1-infected individuals, monoclonal anti-envelope antibodies or antibodies/antagonists against CD4, CXCR4, and CCR5 were not able to prevent infection by the 92UG046-T8 isolate. This is the first report showing a primary HIV-1 variant with truncated cytoplasmic tail which is highly fusogenic and can infect a broad range of cells from human and non-human origins. In vivo evolution of similar HIV-1 mutants may have important implications in AIDS pathogenesis.

  2. Assessment of Phytostabilization Success in Metalliferous Acid Mine Tailings

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Root, R. A.; Hammond, C.; Amistadi, M. K.; Maier, R. M.; Chorover, J.

    2014-12-01

    Legacy mine tailings are a significant source of metal(loid)s due to wind and water erosion, especially in the arid southwest, and exposure to fugative dusts presents a health risk to surrounding populations. Compost assisted phytostabilization has been implemented to reduce off site emissions at the Iron King Mine U.S. Superfund Site in central Arizona, concurrent with a greenhouse mesocosm study for detailed study of subsurface mechanisms. Quantification of plant available toxic metal(loid)s in the amended tailings was accessed with a targeted single extraction of diethylenetriaminepentaactic acid (DTPA). Greenhouse mesocosms (1m dia, 0.4 m deep), run in triplicate, mimicked field treatments with: i) tailings only control (TO), ii) tailings plus 15 wt% compost (TC), iii) TC + quailbush seeds (TCA), and iv) TC + buffalo grass seeds (TCB). Core samples collected at 3-month intervals for 1 year were dissected by depth (10 cm each) for analysis. DTPA results indicated that compost treated samples decreased plant availability of Al, As, Cd, Cu, Fe, and Pb but increased Mn and Zn compared with TO. TCB decreased plant available metal(loid)s at all depths, whereas TCA plant available Al, As, Cd, Cu, Fe, Mn and Zn increased in the deeper 20-30cm and 30-40 cm relative to TCB. Samples from the greenhouse were compared to tailings from both the field site and tailings impacted soils used to grow vegetables. Mineral transformations and metal complexation, in the pre- and post-extracted tailings were analyzed by synchrotron transmission XRD and FTIR spectroscopy. The temporal change in plant available metal(loid)s in response to phytostabilization indicates mineralogical alteration that improves soil quality by reducing plant available metal(loid)s. These results will aid in the understanding and efficacy of phytostabilization as a means of remediating and reducing toxicity on mine tailings as well as providing information on health risk management in the region.

  3. [Leaching kinetics of josephinite tailings with sulfuric acid].

    PubMed

    Chen, An-An; Zhou, Shao-Qi; Huang, Peng-Fei

    2013-07-01

    Leaching is the most important step of josephinite tailing recycle technology. This step can separate the valuable metal Mg from Si and other impure metal. Effects of sulfuric acid on leaching Mg efficiency from josephinite tailings were investigated. To obtain the leaching behavior, a modified unreacted shrinking core model that based on the experimental data was used to determine the dissolution kinetic parameters. The model was significant and showed that the dissolution of Mg2+ in josephinite tailing was controlled by the produce layer diffusion, apparent activation reaction energy E = 34.04 kJ x mol(-1). The produce layers obstruct the forward reaction of the dissolution of Mg2+. PMID:24028005

  4. Naturally occurring hybrids derived from γ-amino acids and sugars with potential tail to tail ether-bonds

    PubMed Central

    Feng, Zi-ming; Zhan, Zhi-lai; Yang, Ya-nan; Jiang, Jian-shuang; Zhang, Pei-cheng

    2016-01-01

    The basic substances of life include various amino acids and sugars. To search such molecules is the precondition to understand the essential nature. Here we reported four unprecedented hybrids of γ-amino acids and sugars from the roots of Ranunculus ternatus, which possess potential tail to tail ether-connected (6,6-ether-connected) modes in the sugar moiety. The structures of these hybrids were elucidated by extensive analyses of spectra and calculated electronic circular dichroism (ECD) method. PMID:27166276

  5. Naturally occurring hybrids derived from γ-amino acids and sugars with potential tail to tail ether-bonds.

    PubMed

    Feng, Zi-Ming; Zhan, Zhi-Lai; Yang, Ya-Nan; Jiang, Jian-Shuang; Zhang, Pei-Cheng

    2016-01-01

    The basic substances of life include various amino acids and sugars. To search such molecules is the precondition to understand the essential nature. Here we reported four unprecedented hybrids of γ-amino acids and sugars from the roots of Ranunculus ternatus, which possess potential tail to tail ether-connected (6,6-ether-connected) modes in the sugar moiety. The structures of these hybrids were elucidated by extensive analyses of spectra and calculated electronic circular dichroism (ECD) method. PMID:27166276

  6. Naturally occurring hybrids derived from γ-amino acids and sugars with potential tail to tail ether-bonds

    NASA Astrophysics Data System (ADS)

    Feng, Zi-Ming; Zhan, Zhi-Lai; Yang, Ya-Nan; Jiang, Jian-Shuang; Zhang, Pei-Cheng

    2016-05-01

    The basic substances of life include various amino acids and sugars. To search such molecules is the precondition to understand the essential nature. Here we reported four unprecedented hybrids of γ-amino acids and sugars from the roots of Ranunculus ternatus, which possess potential tail to tail ether-connected (6,6-ether-connected) modes in the sugar moiety. The structures of these hybrids were elucidated by extensive analyses of spectra and calculated electronic circular dichroism (ECD) method.

  7. Association between cytoplasmic CRABP2, altered retinoic acid signaling, and poor prognosis in glioblastoma.

    PubMed

    Liu, Rong-Zong; Li, Shuai; Garcia, Elizabeth; Glubrecht, Darryl D; Yin Poon, Ho; Easaw, Jacob C; Godbout, Roseline

    2016-06-01

    Retinoic acid (RA), a metabolite of vitamin A, is required for the regulation of growth and development. Aberrant expression of molecules involved in RA signaling has been reported in various cancer types including glioblastoma multiforme (GBM). Cellular retinoic acid-binding protein 2 (CRABP2) has previously been shown to play a key role in the transport of RA to retinoic acid receptors (RARs) to activate their transcription regulatory activity. Here, we demonstrate that CRABP2 is predominantly located in the cytoplasm of GBM tumors. Cytoplasmic, but not nuclear, CRABP2 levels in GBM tumors are associated with poor patient survival. Treatment of malignant glioma cell lines with RA results in a dose-dependent increase in accumulation of CRABP2 in the cytoplasm. CRABP2 knockdown reduces proliferation rates of malignant glioma cells, and enhances RA-induced RAR activation. Levels of CRYAB, a small heat shock protein with anti-apoptotic activity, and GFAP, an astrocyte-specific intermediate filament protein, are greatly reduced in CRABP2-depleted cells. Restoration of CRYAB expression partially but significantly reversed the effect of CRABP2 depletion on RAR activation. Our combined in vivo and in vitro data indicate that: (i) CRABP2 is an important determinant of clinical outcome in GBM patients, and (ii) the mechanism of action of CRABP2 in GBM involves sequestration of RA in the cytoplasm and activation of an anti-apoptotic pathway, thereby enhancing proliferation and preventing RA-mediated cell death and differentiation. We propose that reducing CRABP2 levels may enhance the therapeutic index of RA in GBM patients. GLIA 2016;64:963-976. PMID:26893190

  8. Control of lipid organization and actin assembly during clathrin-mediated endocytosis by the cytoplasmic tail of the rhomboid protein Rbd2

    PubMed Central

    Cortesio, Christa L.; Lewellyn, Eric B.; Drubin, David G.

    2015-01-01

    Clathrin-mediated endocytosis (CME) is facilitated by a precisely regulated burst of actin assembly. PtdIns(4,5)P2 is an important signaling lipid with conserved roles in CME and actin assembly regulation. Rhomboid family multipass transmembrane proteins regulate diverse cellular processes; however, rhomboid-mediated CME regulation has not been described. We report that yeast lacking the rhomboid protein Rbd2 exhibit accelerated endocytic-site dynamics and premature actin assembly during CME through a PtdIns(4,5)P2-dependent mechanism. Combined genetic and biochemical studies showed that the cytoplasmic tail of Rbd2 binds directly to PtdIns(4,5)P2 and is sufficient for Rbd2's role in actin regulation. Analysis of an Rbd2 mutant with diminished PtdIns(4,5)P2-binding capacity indicates that this interaction is necessary for the temporal regulation of actin assembly during CME. The cytoplasmic tail of Rbd2 appears to modulate PtdIns(4,5)P2 distribution on the cell cortex. The syndapin-like F-BAR protein Bzz1 functions in a pathway with Rbd2 to control the timing of type 1 myosin recruitment and actin polymerization onset during CME. This work reveals that the previously unstudied rhomboid protein Rbd2 functions in vivo at the nexus of three highly conserved processes: lipid regulation, endocytic regulation, and cytoskeletal function. PMID:25694450

  9. Control of lipid organization and actin assembly during clathrin-mediated endocytosis by the cytoplasmic tail of the rhomboid protein Rbd2.

    PubMed

    Cortesio, Christa L; Lewellyn, Eric B; Drubin, David G

    2015-04-15

    Clathrin-mediated endocytosis (CME) is facilitated by a precisely regulated burst of actin assembly. PtdIns(4,5)P2 is an important signaling lipid with conserved roles in CME and actin assembly regulation. Rhomboid family multipass transmembrane proteins regulate diverse cellular processes; however, rhomboid-mediated CME regulation has not been described. We report that yeast lacking the rhomboid protein Rbd2 exhibit accelerated endocytic-site dynamics and premature actin assembly during CME through a PtdIns(4,5)P2-dependent mechanism. Combined genetic and biochemical studies showed that the cytoplasmic tail of Rbd2 binds directly to PtdIns(4,5)P2 and is sufficient for Rbd2's role in actin regulation. Analysis of an Rbd2 mutant with diminished PtdIns(4,5)P2-binding capacity indicates that this interaction is necessary for the temporal regulation of actin assembly during CME. The cytoplasmic tail of Rbd2 appears to modulate PtdIns(4,5)P2 distribution on the cell cortex. The syndapin-like F-BAR protein Bzz1 functions in a pathway with Rbd2 to control the timing of type 1 myosin recruitment and actin polymerization onset during CME. This work reveals that the previously unstudied rhomboid protein Rbd2 functions in vivo at the nexus of three highly conserved processes: lipid regulation, endocytic regulation, and cytoskeletal function. PMID:25694450

  10. Low molecular weight carboxylic acids in oxidizing porphyry copper tailings.

    PubMed

    Dold, Bernhard; Blowes, David W; Dickhout, Ralph; Spangenberg, Jorge E; Pfeifer, Hans-Rudolf

    2005-04-15

    The distribution of low molecular weight carboxylic acids (LMWCA) was investigated in pore water profiles from two porphyry copper tailings impoundments in Chile (Piuquenes at La Andina and Cauquenes at El Teniente mine). The objectives of this study were (1) to determine the distribution of LMWCA, which are interpreted to be the metabolic byproducts of the autotroph microbial community in this low organic carbon system, and (2) to infer the potential role of these acids in cycling of Fe and other elements in the tailings impoundments. The speciation and mobility of iron, and potential for the release of H+ via hydrolysis of the ferric iron, are key factors in the formation of acid mine drainage in sulfidic mine wastes. In the low-pH oxidation zone of the Piuquenes tailings, Fe(III) is the dominant iron species and shows high mobility. LMWCA, which occur mainly between the oxidation front down to 300 cm below the tailings surface at both locations (e.g., max concentrations of 0.12 mmol/L formate, 0.17 mmol/L acetate, and 0.01 mmol/L pyruvate at Piuquenes and 0.14 mmol/L formate, 0.14 mmol/L acetate, and 0.006 mmol/L pyruvate at Cauquenes), are observed at the same location as high Fe concentrations (up to 71.2 mmol/L Fe(II) and 16.1 mmol/L Fe(III), respectively). In this zone, secondary Fe(III) hydroxides are depleted. Our data suggest that LMWCA may influence the mobility of iron in two ways. First, complexation of Fe(III), through formation of bidentate Fe(III)-LMWCA complexes (e.g., pyruvate, oxalate), may enhance the dissolution of Fe(III) (oxy)hydroxides or may prevent precipitation of Fe(III) (oxy)hydroxides. Soluble Fe(III) chelate complexes which may be mobilized downward and convert to Fe(II) by Fe(III) reducing bacteria. Second, monodentate LMWCA (e.g., acetate and formate) can be used by iron-reducing bacteria as electron donors (e.g., Acidophilum spp.), with ferric iron as the electron acceptor. These processes may, in part, explain the low abundances

  11. The Influenza M2 Cytoplasmic Tail Changes the Proton-Exchange Equilibria and the Backbone Conformation of the Transmembrane Histidine Residue to Facilitate Proton Conduction

    PubMed Central

    Liao, Shu Y.; Yang, Yu; Tietze, Daniel; Hong, Mei

    2015-01-01

    The influenza M2 protein forms an acid-activated tetrameric proton channel important for the virus lifecycle. Residue His37 in the transmembrane domain is responsible for channel activation and proton selectivity. While the structure and dynamics of His37 have been well studied in TM peptide constructs, it has not been investigated in the presence of the full cytoplasmic domain, which increases the proton conductivity by 2-fold compared to the TM peptide. We report here 13C and 15N chemical shifts of His37 in the cytoplasmic-containing M2(21-97), and show that cationic histidines are already present at neutral pH, in contrast to the TM peptide, indicating that the cytoplasmic domain shifts the protonation equilibria. Quantification of the imidazole 15N intensities yielded two resolved proton dissociation constants (pKa’s) of 7.1 and 5.4, which differ from the TM result but resemble the M2(18–60) result, suggesting cooperative proton binding. The average His37 pKa is higher for M2(21–97) than for the shorter constructs. We attribute this higher pKa to direct and indirect effects of the cytoplasmic domain, which is rich in acidic residues. 2D 13C-13C correlation spectra reveal seven His37 Cα-Cβ cross peaks at different pH, some of which are unique to the cytoplasmic-containing M2 and correspond to more ideal α-helical conformations. Based on the pH at which these chemical shifts appear and their sidechain structures, we assign these conformations to His37 in differently charged tetramers. Thus, the cytoplasmic domain facilitates proton conduction through the transmembrane pore by modifying the His37-water proton-exchange equilibria and the His37 backbone conformational distribution. PMID:25892574

  12. Prolonged activation of phospholipase D in Chinese hamster ovary cells expressing platelet-activating-factor receptor lacking cytoplasmic C-terminal tail.

    PubMed

    Liu, B; Nakashima, S; Adachi, T; Ito, Y; Takano, T; Shimizu, T; Nozawa, Y

    1997-10-01

    The mechanism and role of phospholipase D (PLD) activation by platelet-activating factor (PAF) were examined with Chinese hamster ovary cells stably expressing wild-type PAF receptor (WT-H cells) and truncated PAF receptor lacking the C-terminal cytoplasmic tail (D-H cells). Treatment of D-H cells with PAF resulted in the rapid formation of Ins(1,4,5)P3, which was followed by a sustained phase for more than 10 min. In these cells, PAF-induced PLD activation lasted for more than 20 min. In contrast, PLD activation in WT-H cells was transient. PAF stimulation caused the biphasic formation of 1,2-diacylglycerol (DG) in both types of cell. The first phase was rapid and transient, coinciding with the Ins(1,4,5)P3 peak. The second sustained phase of DG formation was attenuated by butanol, which produces phosphatidylbutanol at the expense of phosphatidic acid (PA) by transphosphatidylation activity of PLD, and by propranolol, a selective inhibitor for PA phosphohydrolase catalysing the conversion of PA into DG. The DG level returned nearly to basal at 20 min after PAF stimulation in WT-H cells, whereas in D-H cells the elevated DG level was sustained for more than 20 min. The profile of translocation of protein kinase Calpha (PKCalpha) to membrane was similar to that of DG formation. In WT-H cells, PKCalpha was transiently associated with membranes and then returned to the cytosol. However, in D-H cells PKCalpha was rapidly translocated to and remained in membranes for more than 20 min. Butanol suppressed this sustained translocation of PKCalpha. Furthermore the mRNA levels of c-fos and c-jun by PAF in WT-H cells were much lower than those in D-H cells. Propranolol and butanol at concentrations that inhibited the formation of DG suppressed the PAF-induced mRNA expression of c-fos and c-jun. Taken together, the prolonged PLD activation in D-H cells confirmed a primary role for phospholipase C/PKC in PLD activation by PAF. Furthermore the results obtained here suggest that

  13. A retention signal necessary and sufficient for Golgi localization maps to the cytoplasmic tail of a Bunyaviridae (Uukuniemi virus) membrane glycoprotein.

    PubMed

    Andersson, A M; Melin, L; Bean, A; Pettersson, R F

    1997-06-01

    Members of the Bunyaviridae family mature by a budding process in the Golgi complex. The site of maturation is thought to be largely determined by the accumulation of the two spike glycoproteins, G1 and G2, in this organelle. Here we show that the signal for localizing the Uukuniemi virus (a phlebovirus) spike protein complex to the Golgi complex resides in the cytoplasmic tail of G1. We constructed chimeric proteins in which the ectodomain, transmembrane domain (TMD), and cytoplasmic tail (CT) of Uukuniemi virus G1 were exchanged with the corresponding domains of either vesicular stomatitis virus G protein (VSV G), chicken lysozyme, or CD4, all proteins readily transported to the plasma membrane. The chimeras were expressed in HeLa or BHK-21 cells by using either the T7 RNA polymerase-driven vaccinia virus system or the Semliki Forest virus system. The fate of the chimeric proteins was monitored by indirect immunofluorescence, and their localizations were compared by double labeling with markers specific for the Golgi complex. The results showed that the ectodomain and TMD (including the 10 flanking residues on either side of the membrane) of G1 played no apparent role in targeting chimeric proteins to the Golgi complex. Instead, all chimeras containing the CT of G1 were efficiently targeted to the Golgi complex and colocalized with mannosidase II, a Golgi-specific enzyme. Conversely, replacing the CT of G1 with that from VSV G resulted in the efficient transport of the chimeric protein to the cell surface. Progressive deletions of the G1 tail suggested that the Golgi retention signal maps to a region encompassing approximately residues 10 to 50, counting from the proposed border between the TMD and the tail. Both G1 and G2 were found to be acylated, as shown by incorporation of [3H]palmitate into the viral proteins. By mutational analyses of CD4-G1 chimeras, the sites for palmitylation were mapped to two closely spaced cysteine residues in the G1 tail. Changing

  14. Characterization of a Ribonucleic Acid Polymerase Activity Associated with Purified Cytoplasmic Polyhedrosis Virus of the Silkworm Bombyx mori1

    PubMed Central

    Lewandowski, L. J.; Kalmakoff, J.; Tanada, Y.

    1969-01-01

    Purified cytoplasmic-polyhedrosis virus has been found to have associated with it a polymerase activity capable of catalyzing the synthesis of virus-specific, single-stranded ribonucleic acid (RNA) from the double-stranded RNA genome. PMID:16789118

  15. Hepcidin induction by transgenic overexpression of Hfe does not require the Hfe cytoplasmic tail, but does require hemojuvelin

    PubMed Central

    Andrews, Nancy C.; Fleming, Mark D.

    2010-01-01

    Mutations in HFE cause the most common form of hereditary hemochromatosis (HH). We previously showed that liver-specific, transgenic overexpression of murine Hfe stimulates production of the iron regulatory hormone hepcidin. Here, we developed several additional transgenic mouse strains to further interrogate the structural basis of HFE function in the pathophysiology of HH. We hypothesized that the small, cytoplasmic domain of HFE might be necessary for HFE-mediated induction of hepcidin. We demonstrate that, like the full-length protein, overexpression of Hfe proteins lacking the cytoplasmic domain leads to hepcidin induction, iron deficiency and a hypochromic, microcytic anemia. However, high-level expression of a liver-specific Hfe transgene carrying the mouse equivalent of the common HFE C282Y human disease-causing mutation (murine C294Y) did not cause iron deficiency. Furthermore, hepcidin induction by transgenes encoding both WT Hfe and Hfe lacking its cytoplasmic domain is greatly attenuated in the absence of hemojuvelin (Hjv). Our observations indicate that the extracellular and transmembrane domains of Hfe are sufficient, and Hjv is essential, for Hfe-mediated induction of hepcidin expression. PMID:20837779

  16. Function of the cytoplasmic tail of human calcitonin receptor-like receptor in complex with receptor activity-modifying protein 2

    SciTech Connect

    Kuwasako, Kenji; Kitamura, Kazuo; Nagata, Sayaka; Hikosaka, Tomomi; Kato, Johji

    2010-02-12

    Receptor activity-modifying protein 2 (RAMP2) enables calcitonin receptor-like receptor (CRLR) to form an adrenomedullin (AM)-specific receptor. Here we investigated the function of the cytoplasmic C-terminal tail (C-tail) of human (h)CRLR by co-transfecting its C-terminal mutants into HEK-293 cells stably expressing hRAMP2. Deleting the C-tail from CRLR disrupted AM-evoked cAMP production or receptor internalization, but did not affect [{sup 125}I]AM binding. We found that CRLR residues 428-439 are required for AM-evoked cAMP production, though deleting this region had little effect on receptor internalization. Moreover, pretreatment with pertussis toxin (100 ng/mL) led to significant increases in AM-induced cAMP production via wild-type CRLR/RAMP2 complexes. This effect was canceled by deleting CRLR residues 454-457, suggesting Gi couples to this region. Flow cytometric analysis revealed that CRLR truncation mutants lacking residues in the Ser/Thr-rich region extending from Ser{sup 449} to Ser{sup 467} were unable to undergo AM-induced receptor internalization and, in contrast to the effect on wild-type CRLR, overexpression of GPCR kinases-2, -3 and -4 failed to promote internalization of CRLR mutants lacking residues 449-467. Thus, the hCRLR C-tail is crucial for AM-evoked cAMP production and internalization of the CRLR/RAMP2, while the receptor internalization is dependent on the aforementioned GPCR kinases, but not Gs coupling.

  17. Reclamation of acidic copper mine tailings using municipal biosolids

    SciTech Connect

    Rogers, M.T.; Thompson, T.L.; Bengson, S.A.

    1998-12-31

    Reclamation of copper mine tailings in a cost effective, successful, and sustainable manner is an ongoing area of evaluation in the arid southwest. A study was initiated in September, 1996 near Hayden, Arizona to evaluate the use of municipal biosolids for reclaiming acidic copper mine tailings (pH of 2.5 to 4.0). The main objectives of the study were to (1) define an appropriate level of biosolids application for optimum plant growth, and (2) evaluate the effects of green waste and lime amendments. The experiment was a randomized complete block design with four biosolid rates of 20, 70, 100 and 135 dry tons/acre, three amendment treatments (none, green waste, and green waste plus lime); with three replications. Non-replicated controls (no treatment, green waste only and lime only) were included for comparison. Shortly after biosolids incorporation to a depth of 10--12 inches, composite soil samples (0--12 inches) of each plot were taken. Biosolids incorporation increased the pH of the tailings (>5.75) and additional increases in pH were noted with lime application. In January 1997, the plots were seeded and sprinkler irrigation was commenced. A total of 4.47 inches of rainfall and 3.8 inches of irrigation were applied until harvest in May 1997. Data from the first growing season indicates optimum growth (>66 lbs/acre) at biosolids rates of 70--100 dry tons/acre. There was a significant positive effect on growth of green waste and lime amendments. Surface NO{sub 3}-N concentrations in biosolids amended plots were greatly reduced (from 23 to 6 mg/kg) by addition of green waste. There was no evidence for NO{sub 3}N leaching below 12 inches.

  18. Increased infectivity in human cells and resistance to antibody-mediated neutralization by truncation of the SIV gp41 cytoplasmic tail.

    PubMed

    Kuwata, Takeo; Kaori, Takaki; Enomoto, Ikumi; Yoshimura, Kazuhisa; Matsushita, Shuzo

    2013-01-01

    The role of antibodies in protecting the host from human immunodeficiency virus type 1 (HIV-1) infection is of considerable interest, particularly because the RV144 trial results suggest that antibodies contribute to protection. Although infection of non-human primates with simian immunodeficiency virus (SIV) is commonly used as an animal model of HIV-1 infection, the viral epitopes that elicit potent and broad neutralizing antibodies to SIV have not been identified. We isolated a monoclonal antibody (MAb) B404 that potently and broadly neutralizes various SIV strains. B404 targets a conformational epitope comprising the V3 and V4 loops of Env that intensely exposed when Env binds CD4. B404-resistant variants were obtained by passaging viruses in the presence of increasing concentration of B404 in PM1/CCR5 cells. Genetic analysis revealed that the Q733stop mutation, which truncates the cytoplasmic tail of gp41, was the first major substitution in Env during passage. The maximal inhibition by B404 and other MAbs were significantly decreased against a recombinant virus with a gp41 truncation compared with the parental SIVmac316. This indicates that the gp41 truncation was associated with resistance to antibody-mediated neutralization. The infectivities of the recombinant virus with the gp41 truncation were 7,900-, 1,000-, and 140-fold higher than those of SIVmac316 in PM1, PM1/CCR5, and TZM-bl cells, respectively. Immunoblotting analysis revealed that the gp41 truncation enhanced the incorporation of Env into virions. The effect of the gp41 truncation on infectivity was not obvious in the HSC-F macaque cell line, although the resistance of viruses harboring the gp41 truncation to neutralization was maintained. These results suggest that viruses with a truncated gp41 cytoplasmic tail were selected by increased infectivity in human cells and by acquiring resistance to neutralizing antibody. PMID:23717307

  19. G-protein-coupled receptors for neurotransmitter amino acids: C-terminal tails, crowded signalosomes.

    PubMed Central

    El Far, Oussama; Betz, Heinrich

    2002-01-01

    G-protein-coupled receptors (GPCRs) represent a superfamily of highly diverse integral membrane proteins that transduce external signals to different subcellular compartments, including nuclei, via trimeric G-proteins. By differential activation of diffusible G(alpha) and membrane-bound G(beta)gamma subunits, GPCRs might act on both cytoplasmic/intracellular and plasma-membrane-bound effector systems. The coupling efficiency and the plasma membrane localization of GPCRs are regulated by a variety of interacting proteins. In this review, we discuss recently disclosed protein interactions found with the cytoplasmic C-terminal tail regions of two types of presynaptic neurotransmitter receptors, the group III metabotropic glutamate receptors and the gamma-aminobutyric acid type-B receptors (GABA(B)Rs). Calmodulin binding to mGluR7 and other group III mGluRs may provide a Ca(2+)-dependent switch for unidirectional (G(alpha)) versus bidirectional (G(alpha) and G(beta)gamma) signalling to downstream effector proteins. In addition, clustering of mGluR7 by PICK1 (protein interacting with C-kinase 1), a polyspecific PDZ (PSD-95/Dlg1/ZO-1) domain containing synaptic organizer protein, sheds light on how higher-order receptor complexes with regulatory enzymes (or 'signalosomes') could be formed. The interaction of GABA(B)Rs with the adaptor protein 14-3-3 and the transcription factor ATF4 (activating transcription factor 4) suggests novel regulatory pathways for G-protein signalling, cytoskeletal reorganization and nuclear gene expression: processes that may all contribute to synaptic plasticity. PMID:12006104

  20. Involvement of a universal amino acid synthesis impediment in cytoplasmic male sterility in pepper.

    PubMed

    Fang, Xianping; Fu, Hong-Fei; Gong, Zhen-Hui; Chai, Wei-Guo

    2016-01-01

    To explore the mechanisms of pepper (Capsicum annuum L.) cytoplasmic male sterility (CMS), we studied the different maturation processes of sterile and fertile pepper anthers. A paraffin section analysis of the sterile anthers indicated an abnormality of the tapetal layer and an over-vacuolization of the cells. The quantitative proteomics results showed that the expression of histidinol dehydrogenase (HDH), dihydroxy-acid dehydratase (DAD), aspartate aminotransferase (ATAAT), cysteine synthase (CS), delta-1-pyrroline-5-carboxylate synthase (P5CS), and glutamate synthetase (GS) in the amino acid synthesis pathway decreased by more than 1.5-fold. Furthermore, the mRNA and protein expression levels of DAD, ATAAT, CS and P5CS showed a 2- to 16-fold increase in the maintainer line anthers. We also found that most of the amino acid content levels decreased to varying degrees during the anther tapetum period of the sterile line, whereas these levels increased in the maintainer line. The results of our study indicate that during pepper anther development, changes in amino acid synthesis are significant and accompany abnormal tapetum maturity, which is most likely an important cause of male sterility in pepper. PMID:26987793

  1. Involvement of a universal amino acid synthesis impediment in cytoplasmic male sterility in pepper

    PubMed Central

    Fang, Xianping; Fu, Hong-Fei; Gong, Zhen-Hui; Chai, Wei-Guo

    2016-01-01

    To explore the mechanisms of pepper (Capsicum annuum L.) cytoplasmic male sterility (CMS), we studied the different maturation processes of sterile and fertile pepper anthers. A paraffin section analysis of the sterile anthers indicated an abnormality of the tapetal layer and an over-vacuolization of the cells. The quantitative proteomics results showed that the expression of histidinol dehydrogenase (HDH), dihydroxy-acid dehydratase (DAD), aspartate aminotransferase (ATAAT), cysteine synthase (CS), delta-1-pyrroline-5-carboxylate synthase (P5CS), and glutamate synthetase (GS) in the amino acid synthesis pathway decreased by more than 1.5-fold. Furthermore, the mRNA and protein expression levels of DAD, ATAAT, CS and P5CS showed a 2- to 16-fold increase in the maintainer line anthers. We also found that most of the amino acid content levels decreased to varying degrees during the anther tapetum period of the sterile line, whereas these levels increased in the maintainer line. The results of our study indicate that during pepper anther development, changes in amino acid synthesis are significant and accompany abnormal tapetum maturity, which is most likely an important cause of male sterility in pepper. PMID:26987793

  2. A Cytoplasmic Tail Determinant in HIV-1 Vpu Mediates Targeting of Tetherin for Endosomal Degradation and Counteracts Interferon-Induced Restriction

    PubMed Central

    Kueck, Tonya; Neil, Stuart J. D.

    2012-01-01

    The HIV-1 accessory protein Vpu counteracts tetherin (BST-2/CD317) by preventing its incorporation into virions, reducing its surface expression, and ultimately promoting its degradation. Here we characterize a putative trafficking motif, EXXXLV, in the second alpha helix of the subtype-B Vpu cytoplasmic tail as being required for efficient tetherin antagonism. Mutation of this motif prevents ESCRT-dependent degradation of tetherin/Vpu complexes, tetherin cell surface downregulation, but not its physical interaction with Vpu. Importantly, this motif is required for efficient cell-free virion release from CD4+ T cells, particularly after their exposure to type-1 interferon, indicating that the ability to reduce surface tetherin levels and promote its degradation is important to counteract restriction under conditions that the virus likely encounters in vivo. Vpu EXXXLV mutants accumulate with tetherin at the cell surface and in endosomal compartments, but retain the ability to bind both β-TrCP2 and HRS, indicating that this motif is required for a post-binding trafficking event that commits tetherin for ESCRT-dependent degradation and prevents its transit to the plasma membrane and viral budding zones. We further found that while Vpu function is dependent on clathrin, and the entire second alpha helix of the Vpu tail can be functionally complemented by a clathrin adaptor binding peptide derived from HIV-1 Nef, none of the canonical clathrin adaptors nor retromer are required for this process. Finally we show that residual activity of Vpu EXXXLV mutants requires an intact endocytic motif in tetherin, suggesting that physical association of Vpu with tetherin during its recycling may be sufficient to compromise tetherin activity to some degree. PMID:22479182

  3. Mutation of critical serine residues in HIV-1 matrix result in an envelope incorporation defect which can be rescued by truncation of the gp41 cytoplasmic tail

    SciTech Connect

    Bhatia, Ajay K.; Kaushik, Rajnish; Campbell, Nancy A.; Pontow, Suzanne E.; Ratner, Lee

    2009-02-05

    The human immunodeficiency virus type 1 (HIV-1) matrix (MA) domain is involved in both early and late events of the viral life cycle. Simultaneous mutation of critical serine residues in MA has been shown previously to dramatically reduce phosphorylation of MA. However, the role of phosphorylation in viral replication remains unclear. Viruses harboring serine to alanine substitutions at positions 9, 67, 72, and 77 are severely impaired in their ability to infect target cells. In addition, the serine mutant viruses are defective in their ability to fuse with target cell membranes. Interestingly, both the fusion defect and the infectivity defect can be rescued by truncation of the long cytoplasmic tail of gp41 envelope protein (gp41CT). Sucrose density gradient analysis also reveals that these mutant viruses have reduced levels of gp120 envelope protein incorporated into the virions as compared to wild type virus. Truncation of the gp41CT rescues the envelope incorporation defect. Here we propose a model in which mutation of specific serine residues prevents MA interaction with lipid rafts during HIV-1 assembly and thereby impairs recruitment of envelope to the sites of viral budding.

  4. Identification of the phosphorylation sequence in the cytoplasmic tail of the varicella-zoster virus Fc receptor glycoprotein gpI.

    PubMed Central

    Yao, Z; Jackson, W; Grose, C

    1993-01-01

    Varicella-zoster virus (VZV) glycoprotein gpI, the homolog of herpes simplex virus gE, functions as a receptor for the Fc portion of immunoglobulin G. Like other cell surface receptors, this viral receptor is highly phosphorylated in cell culture. To identify the precise location of the cellular kinase-mediated phosphorylation, we generated a tailless deletion mutant and several point mutants which had altered serine and threonine residues within the cytoplasmic domain of gpI. The mutated and wild-type genes of gpI were transfected and expressed within a vaccinia virus-T7 polymerase transfection system in order to determine what effect these mutations had on the phosphorylation state of the protein in vivo and in vitro. Truncation of the cytoplasmic domain of gpI diminished the phosphorylation of gpI in vivo. Examination of the point mutants established that the major phosphorylation sequence of gpI was located between amino acids 593 and 598, a site which included four phosphorylatable serine and threonine residues. Phosphorylation analyses of the mutant and wild-type glycoproteins confirmed that gpI was a substrate for casein kinase II, with threonines 596 and 598 being critical residues. Although the mutant glycoproteins were phosphorylated by casein kinase I, protease V8 partial digestion profiles suggested that casein kinase II exerted the major effect. Thus, these mutagenesis studies demonstrated that the gpI cytoplasmic sequence Ser-Glu-Ser-Thr-Asp-Thr was phosphorylated in mammalian cells in the absence of any other herpesvirus products. Since the region defined by transfection was consistent with results obtained with in vitro phosphorylation by casein kinase II, we propose that VZV gpI is a physiologic substrate for casein kinase II. Immunofluorescence and pulse-chase experiments demonstrated that the mutant glycoproteins were processed and transported to the outer cell membrane. Images PMID:8392591

  5. Phosphorylation of Serine Residues in the C-terminal Cytoplasmic Tail of Connexin43 Regulates Proliferation of Ovarian Granulosa Cells

    PubMed Central

    Dyce, Paul W.; Norris, Rachael P.; Lampe, Paul D.; Kidder, Gerald M.

    2013-01-01

    Connexin43 (Cx43) forms 22 s gap junctions that couple the granulosa cells of ovarian follicles. In Cx43 knockout mice, follicle growth is restricted due to impaired granulosa cell proliferation. We have used these mice to examine the importance of specific Cx43 phosphorylation sites in follicle growth. Serines at residues 255, 262, 279 and 282 are MAP kinase substrates that, when phosphorylated, reduce junctional conductance. Mutant forms of Cx43 were constructed with these serines replaced with amino acids that cannot be phosphorylated. These mutants were transduced into Cx43 knockout ovarian somatic cells which were combined with wildtype oocytes and grafted into immunocompromised female mice permitting follicle growth in vivo. Despite residues 255 or 262 being mutated to prevent their being phosphorylated, recombinant ovaries constructed with these mutants were able to rescue the null phenotype, restoring complete folliculogenesis. In contrast, Cx43 with serine to alanine mutations at both residues 279 and 282 or at all four residues failed to rescue folliculogenesis; the mutant molecules were largely confined to intracellular sites, with few gap junctions. Using an in vitro proliferation assay, we confirmed a decrease in proliferation of granulosa cells expressing the double mutant construct. These results indicate that Cx43 phosphorylation by MAP kinase at serines 279 and 282 occurs in granulosa cells of early follicles and that this is involved in regulating follicle development. PMID:22729691

  6. Site-specific study on stabilization of acid-generating mine tailings using coal fly ash

    SciTech Connect

    Shang, J.Q.; Wang, H.L.; Kovac, V.; Fyfe, J.

    2006-03-15

    A site-specific study on stabilizing acid-generating mine tailings from Sudbury Mine using a coal fly ash from Nanticoke Generating Station is presented in this paper. The objective of the study is to evaluate the feasibility of codisposal of the fly ash and mine tailings to reduce environmental impacts of Sudbury tailings disposal sites. The study includes three phases, i.e., characterization of the mine tailings, and coal fly ash, oxidation tests on the mine tailings and kinetic column permeation tests. The results of the experiments indicate that when permeated with acid mine drainage, the hydraulic conductivity of Nanticoke coal fly ash decreased more than three orders of magnitude (from 1 x 10{sup -6} to 1 x 10{sup -9} cm/s), mainly due to chemical reactions between the ash solids and acid mine drainage. Furthermore, the hydraulic gradient required for acid mine drainage to break through the coal fly ash is increased up to ten times (from 17 to 150) as compared with that for water. The results also show that the leachate from coal fly ash neutralizes the acidic pore fluid of mine tailings. The concentrations of trace elements in effluents from all kinetic column permeation tests indicated that coplacement of coal fly ash with mine tailings has the benefit of immobilizing trace elements, especially heavy metals. All regulated element concentrations from effluent during testing are well below the leachate quality criteria set by the local regulatory authority.

  7. The Envelope Cytoplasmic Tail of HIV-1 Subtype C Contributes to Poor Replication Capacity through Low Viral Infectivity and Cell-to-Cell Transmission.

    PubMed

    Santos da Silva, Eveline; Mulinge, Martin; Lemaire, Morgane; Masquelier, Cécile; Beraud, Cyprien; Rybicki, Arkadiusz; Servais, Jean-Yves; Iserentant, Gilles; Schmit, Jean-Claude; Seguin-Devaux, Carole; Perez Bercoff, Danielle

    2016-01-01

    The cytoplasmic tail (gp41CT) of the HIV-1 envelope (Env) mediates Env incorporation into virions and regulates Env intracellular trafficking. Little is known about the functional impact of variability in this domain. To address this issue, we compared the replication of recombinant virus pairs carrying the full Env (Env viruses) or the Env ectodomain fused to the gp41CT of NL4.3 (EnvEC viruses) (12 subtype C and 10 subtype B pairs) in primary CD4+ T-cells and monocyte-derived-macrophages (MDMs). In CD4+ T-cells, replication was as follows: B-EnvEC = B-Env>C-EnvEC>C-Env, indicating that the gp41CT of subtype C contributes to the low replicative capacity of this subtype. In MDMs, in contrast, replication capacity was comparable for all viruses regardless of subtype and of gp41CT. In CD4+ T-cells, viral entry, viral release and viral gene expression were similar. However, infectivity of free virions and cell-to-cell transmission of C-Env viruses released by CD4+ T-cells was lower, suggestive of lower Env incorporation into virions. Subtype C matrix only minimally rescued viral replication and failed to restore infectivity of free viruses and cell-to-cell transmission. Taken together, these results show that polymorphisms in the gp41CT contribute to viral replication capacity and suggest that the number of Env spikes per virion may vary across subtypes. These findings should be taken into consideration in the design of vaccines. PMID:27598717

  8. Geophysical delineation of acidity and salinity in the Central Manitoba gold mine tailings pile, Manitoba, Canada

    NASA Astrophysics Data System (ADS)

    Tycholiz, C.; Ferguson, I. J.; Sherriff, B. L.; Cordeiro, M.; Sri Ranjan, R.; Pérez-Flores, M. A.

    2016-08-01

    Surface electrical and electromagnetic geophysical methods can map enhanced electrical conductivity caused by acid mine drainage in mine tailings piles. In this case study, we investigate quantitative relationships between geophysical responses and the electrical conductivity, acidity and salinity of tailing samples at the Central Manitoba Mine tailings in Manitoba, Canada. Previous electromagnetic surveys at the site identified zones of enhanced conductivity that were hypothesized to be caused by acid mine drainage. In the present study, high-resolution EM31 and DC-resistivity measurements were made on a profile through a zone of enhanced conductivity and laboratory measurements of salinity and pH were made on saturation paste extracts from an array of tailing samples collected from the upper 2 m of tailings along the profile. Observed spatial correlation of pH and pore-fluid salinity in the tailings samples confirms that the enhanced conductivity in the Central Manitoba Mine tailings is due to acid mine drainage. Contoured cross-sections of the data indicate that the acid mine drainage is concentrated near the base of the oxidized zone in the thicker parts of the tailings pile. The zone of increased acidity extends to the surface on sloping margins causing an increase in apparent conductivity in shallow penetrating geophysical responses. The quantitative relationship between measured pH and salinity shows that the conductivity increase associated with the acid mine drainage is due only in part to conduction by ions produced from dissociation of sulfuric acid. Comparison of the observations with fluid conductivity estimates based on statistical relationships of pH and ion concentrations in water samples from across the tailings pile shows that Ca2 + and Mg2 + ions also make significant contributions to the conductivity at all values of pH and Cu2 +, Al3 + and Fe3 + ions make additional contributions at low pH. Variability in the measured conductivity at constant

  9. The Antifungal Eugenol Perturbs Dual Aromatic and Branched-Chain Amino Acid Permeases in the Cytoplasmic Membrane of Yeast

    PubMed Central

    Darvishi, Emad; Omidi, Mansoor; Bushehri, Ali Akbar Shahnejat; Golshani, Ashkan; Smith, Myron L.

    2013-01-01

    Eugenol is an aromatic component of clove oil that has therapeutic potential as an antifungal drug, although its mode of action and precise cellular target(s) remain ambiguous. To address this knowledge gap, a chemical-genetic profile analysis of eugenol was done using ∼4700 haploid Saccharomyces cerevisiae gene deletion mutants to reveal 21 deletion mutants with the greatest degree of susceptibility. Cellular roles of deleted genes in the most susceptible mutants indicate that the main targets for eugenol include pathways involved in biosynthesis and transport of aromatic and branched-chain amino acids. Follow-up analyses showed inhibitory effects of eugenol on amino acid permeases in the yeast cytoplasmic membrane. Furthermore, phenotypic suppression analysis revealed that eugenol interferes with two permeases, Tat1p and Gap1p, which are both involved in dual transport of aromatic and branched-chain amino acids through the yeast cytoplasmic membrane. Perturbation of cytoplasmic permeases represents a novel antifungal target and may explain previous observations that exposure to eugenol results in leakage of cell contents. Eugenol exposure may also contribute to amino acid starvation and thus holds promise as an anticancer therapeutic drug. Finally, this study provides further evidence of the usefulness of the yeast Gene Deletion Array approach in uncovering the mode of action of natural health products. PMID:24204588

  10. A single amino acid change in the cytoplasmic domain of the simian immunodeficiency virus transmembrane molecule increases envelope glycoprotein expression on infected cells.

    PubMed Central

    LaBranche, C C; Sauter, M M; Haggarty, B S; Vance, P J; Romano, J; Hart, T K; Bugelski, P J; Marsh, M; Hoxie, J A

    1995-01-01

    We have described a virus termed CP-MAC, derived from the BK28 molecular clone of simian immunodeficiency virus, that was remarkable for its ability to infect Sup-T1 cells with rapid kinetics, cell fusion, and CD4 down-modulation (C. C. LaBranche, M. M. Sauter, B. S. Haggarty, P. J. Vance, J. Romano, T. K. Hart, P. J. Bugelski, and J. A. Hoxie, J. Virol. 68:5509-5522, 1994 [Erratum 68:7665-7667]). Compared with BK28, CP-MAC exhibited a number of changes in its envelope glycoproteins, including a highly stable association between the external (SU) and transmembrane (TM) molecules, a more rapid electrophoretic mobility of TM, and, of particular interest, a marked increase in the level of envelope protein expression on the surface of infected cells. These changes were shown to be associated with 11 coding mutations in the env gene (5 in SU and 6 in TM). In this report, we demonstrate that a single amino acid mutation of a Tyr to a Cys at position 723 (Y723C) in the TM cytoplasmic domain of CP-MAC is the principal determinant for the increased expression of envelope glycoproteins on the cell surface. When introduced into the env gene of BK28, the Y723C mutation produced up to a 25-fold increase in the levels of SU and TM on chronically infected cells, as determined by fluorescence-activated cell sorter analysis with monoclonal and polyclonal antibodies. A similar effect was observed when a Tyr-to-Cys change was introduced at the analogous position (amino acid 721) in the SIVmac239 molecular clone, which, unlike BK28 does not contain a premature stop codon in its TM cytoplasmic tail. Substituting other amino acids, including Ala, Ile, and Ser, at this position produced increases in surface envelope glycoproteins that were similar to that observed for the Cys substitution, while a Tyr-to-Phe mutation produced a smaller increase. These results could not be accounted for by differences in the kinetics or efficiency of envelope glycoprotein processing or by shedding of SU

  11. Keratin 1 Plays a Critical Role in Golgi Localization of Core 2 N-Acetylglucosaminyltransferase M via Interaction with Its Cytoplasmic Tail*

    PubMed Central

    Petrosyan, Armen; Ali, Mohamed F.; Cheng, Pi-Wan

    2015-01-01

    Core 2 N-acetylglucosaminyltransferase 2/M (C2GnT-M) synthesizes all three β6GlcNAc branch structures found in secreted mucins. Loss of C2GnT-M leads to development of colitis and colon cancer. Recently we have shown that C2GnT-M targets the Golgi at the Giantin site and is recycled by binding to non-muscle myosin IIA, a motor protein, via the cytoplasmic tail (CT). But how this enzyme is retained in the Golgi is not known. Proteomics analysis identifies keratin type II cytoskeletal 1 (KRT1) as a protein pulled down with anti-c-Myc antibody or C2GnT-M CT from the lysate of Panc1 cells expressing bC2GnT-M tagged with c-Myc. Yeast two-hybrid analysis shows that the rod domain of KRT1 interacts directly with the WKR6 motif in the C2GnT-M CT. Knockdown of KRT1 does not affect Golgi morphology but increases the interaction of C2GnT-M with non-muscle myosin IIA and its transportation to the endoplasmic reticulum, ubiquitination, and degradation. During Golgi recovery after brefeldin A treatment, C2GnT-M forms a complex with Giantin before KRT1, demonstrating CT-mediated sequential events of Golgi targeting and retention of C2GnT-M. In HeLa cells transiently expressing C2GnT-M-GFP, knockdown of KRT1 does not affect Golgi morphology but leaves C2GnT-M outside of the Golgi, resulting in the formation of sialyl-T antigen. Interaction of C2GnT-M and KRT1 was also detected in the goblet cells of human colon epithelial tissue and primary culture of colonic epithelial cells. The results indicate that glycosylation and thus the function of glycoconjugates can be regulated by a protein that helps retain a glycosyltransferase in the Golgi. PMID:25605727

  12. Column leaching test to evaluate the use of alkaline industrial wastes to neutralize acid mine tailings

    SciTech Connect

    Doye, I.; Duchesne, J.

    2005-08-01

    Acid mine drainage is a serious environmental problem caused by the oxidation of sulfide minerals that releases highly acidic, sulfate, and metals-rich drainage. In this study, alkaline industrial wastes were mixed with acid mine tailings in order to obtain neutral conditions. A series of column leaching tests were performed to evaluate the behavior of reactive mine tailings amended with alkaline-additions under dynamic conditions. Column tests were conducted of oxidized mine tailings combined with cement kiln dust, red mud bauxite, and mixtures of cement kiln dust with red mud bauxite. The pH results show the addition of 10% of alkaline materials permits the maintenance of near neutral conditions. In the presence of 10% alkaline material, the concentration of toxic metals such as Al, Cu, Fe, Zn are significantly reduced as well as the number of viable cells (Thiobacillus ferrooxidans) compared to control samples.

  13. Long-term stability of earthen materials in contact with acidic tailings solutions

    SciTech Connect

    Peterson, S.R.; Erikson, R.L.; Gee, G.W.

    1982-11-01

    The objectives of the studies documented in this report were to use experimental and geochemical computer modeling tools to assess the long-term environmental impact of leachate movement from acidic uranium mill tailings. Liner failure (i.e., an increase in the permeability of the liner material) was not found to be a problem when various acidic tailings solutions leached through liner materials for periods up to 3 years. On the contrary, materials that contained over 30% clay showed a decrease in permeability with time in the laboratory columns. The high clay materials tested appear suitable for lining tailings impoundment ponds. The decreases in permeability are attributed to pore plugging resulting from the precipitation of minerals and solids. This precipitation takes place due to the increase in pH of the tailings solution brought about by the buffering capacity of the soil. Geochemical modeling predicts, and x-ray characterization confirms, that precipitation of solids from solution is occurring in the acidic tailings solution/liner interactions studied. In conclusion the same mineralogical changes and contaminant reactions predicted by geochemical modeling and observed in laboratory studies were found at a drained evaporation pond (Lucky Mc in Wyoming) with a 4 year history of acid attack.

  14. The intermediate filament protein vimentin binds specifically to a recombinant integrin {alpha}2/{beta}1 cytoplasmic tail complex and co-localizes with native {alpha}2/{beta}1 in endothelial cell focal adhesions

    SciTech Connect

    Kreis, Stephanie; Schoenfeld, Hans-Joachim; Melchior, Chantal; Steiner, Beat; Kieffer, Nelly . E-mail: kieffer@cu.lu

    2005-04-15

    Integrin receptors are crucial players in cell adhesion and migration. Identification and characterization of cellular proteins that interact with their short {alpha} and {beta} cytoplasmic tails will help to elucidate the molecular mechanisms by which integrins mediate bi-directional signaling across the plasma membrane. Integrin {alpha}2{beta}1 is a major collagen receptor but to date, only few proteins have been shown to interact with the {alpha}2 cytoplasmic tail or with the {alpha}2{beta}1 complex. In order to identify novel binding partners of a {alpha}2{beta}1cytoplasmic domain complex, we have generated recombinant GST-fusion proteins, incorporating the leucine zipper heterodimerization cassettes of Jun and Fos. To ascertain proper functionality of the recombinant proteins, interaction with natural binding partners was tested. GST-{alpha}2 and GST-Jun {alpha}2 bound His-tagged calreticulin while GST-{beta}1 and GST-Fos {beta}1 proteins bound talin. In screening assays for novel binding partners, the immobilized GST-Jun {alpha}2/GST-Fos {beta}1 heterodimeric complex, but not the single subunits, interacted specifically with endothelial cell-derived vimentin. Vimentin, an abundant intermediate filament protein, has previously been shown to co-localize with {alpha}v{beta}3-positive focal contacts. Here, we provide evidence that this interaction also occurs with {alpha}2{beta}1-enriched focal adhesions and we further show that this association is lost after prolonged adhesion of endothelial cells to collagen.

  15. Modified Cytoplasmic Ca2+ Sequestration Contributes to Spinal Cord Injury-Induced Augmentation of Nerve-Evoked Contractions in the Rat Tail Artery

    PubMed Central

    Al Dera, Hussain; Callaghan, Brid P.; Brock, James A.

    2014-01-01

    In rat tail artery (RTA), spinal cord injury (SCI) increases nerve-evoked contractions and the contribution of L-type Ca2+ channels to these responses. In RTAs from unoperated rats, these channels play a minor role in contractions and Bay K8644 (L-type channel agonist) mimics the effects of SCI. Here we investigated the mechanisms underlying the facilitatory actions of SCI and Bay K8644 on nerve-evoked contractions of RTAs and the hypothesis that Ca2+ entering via L-type Ca2+ channels is rapidly sequestered by the sarcoplasmic reticulum (SR) limiting its role in contraction. In situ electrochemical detection of noradrenaline was used to assess if Bay K8644 increased noradrenaline release. Perforated patch recordings were used to assess if SCI changed the Ca2+ current recorded in RTA myocytes. Wire myography was used to assess if SCI modified the effects of Bay K8644 and of interrupting SR Ca2+ uptake on nerve-evoked contractions. Bay K8644 did not change noradrenaline-induced oxidation currents. Neither the size nor gating of Ca2+ currents differed between myocytes from sham-operated (control) and SCI rats. Bay K8644 increased nerve-evoked contractions in RTAs from both control and SCI rats, but the magnitude of this effect was reduced by SCI. By contrast, depleting SR Ca2+ stores with ryanodine or cyclopiazonic acid selectively increased nerve-evoked contractions in control RTAs. Cyclopiazonic acid also selectively increased the blockade of these responses by nifedipine (L-type channel blocker) in control RTAs, whereas ryanodine increased the blockade produced by nifedipine in both groups of RTAs. These findings suggest that Ca2+ entering via L-type channels is normally rapidly sequestered limiting its access to the contractile mechanism. Furthermore, the findings suggest SCI reduces the role of this mechanism. PMID:25350563

  16. Susceptibility to virus-cell fusion at the plasma membrane is reduced through expression of HIV gp41 cytoplasmic domains

    SciTech Connect

    Malinowsky, Katharina; Luksza, Julia; Dittmar, Matthias T.

    2008-06-20

    The cytoplasmic tail of the HIV transmembrane protein plays an important role in viral infection. In this study we analyzed the role of retroviral cytoplasmic tails in modulating the cytoskeleton and interfering with virus-cell fusion. HeLaP4 cells expressing different HIV cytoplasmic tail constructs showed reduced acetylated tubulin levels whereas the cytoplasmic tail of MLV did not alter microtubule stability indicating a unique function for the lentiviral cytoplasmic tail. The effect on tubulin is mediated through the membrane proximal region of the HIV cytoplasmic tail and was independent of membrane localization. Site-directed mutagenesis identified three motifs in the HIV-2 cytoplasmic tail required to effect the reduction in acetylated tubulin. Both the Yxx{phi} domain and amino acids 21 to 45 of the HIV-2 cytoplasmic tail need to be present to change the level of acetylated tubulin in transfected cells. T-cells stably expressing one HIV-2 cytoplasmic tail derived construct showed also a reduction in acetylated tubulin thus confirming the importance of this effect not only for HeLaP4 and 293T cells. Challenge experiments using transiently transfected HeLaP4 cells and T cells stably expressing an HIV cytoplasmic tail construct revealed both reduced virus-cell fusion and replication of HIV-1{sub NL4.3} compared to control cells. In the virus-cell fusion assay only virions pseudotyped with either HIV or MLV envelopes showed reduced fusion efficiency, whereas VSV-G pseudotyped virions where not affected by the expression of HIV derived cytoplasmic tail constructs, indicating that fusion at the plasma but not endosomal membrane is affected. Overexpression of human histone-deacetylase 6 (HDAC6) and constitutively active RhoA resulted in a reduction of acetylated tubulin and reduced virus-cell fusion as significant as that observed following expression of HIV cytoplasmic tail constructs. Inhibition of HDAC6 showed a strong increase in acetylated tubulin and

  17. Role of organic acids in promoting colloidal transport of mercury from mine tailings

    USGS Publications Warehouse

    Slowey, A.J.; Johnson, S.B.; Rytuba, J.J.; Brown, Gordon E., Jr.

    2005-01-01

    A number of factors affect the transport of dissolved and paniculate mercury (Hg) from inoperative Hg mines, including the presence of organic acids in the rooting zone of vegetated mine waste. We examined the role of the two most common organic acids in soils (oxalic and citric acid) on Hg transport from such waste by pumping a mixed organic acid solution (pH 5.7) at 1 mL/min through Hg mine tailings columns. For the two total organic acid concentrations investigated (20 ??M and 1 mM), particle-associated Hg was mobilized, with the onset of paniculate Hg transport occurring later for the lower organic acid concentration. Chemical analyses of column effluent indicate that 98 wt % of Hg mobilized from the column was paniculate. Hg speciation was determined using extended X-ray absorption fine structure spectroscopy and transmission electron microscopy, showing that HgS minerals are dominant in the mobilized particles. Hg adsorbed to colloids is another likely mode of transport due to the abundance of Fe-(oxyhydr)oxides, Fe-sulfides, alunite, and jarosite in the tailings to which Hg(II) adsorbs. Organic acids produced by plants are likely to enhance the transport of colloid-associated Hg from vegetated Hg mine tailings by dissolving cements to enable colloid release. ?? 2005 American Chemical Society.

  18. Revegetation of non-Acid-generating, thickened tailings with boreal trees: a greenhouse study.

    PubMed

    Larchevêque, Marie; Desrochers, Annie; Bussière, Bruno; Cartier, Hélène; David, Jean-Sébastien

    2013-01-01

    Tree planting presents clear advantages for mine reclamation that is aimed at achieving rapid reclamation of forested landscapes. A greenhouse study was conducted to evaluate the capacity of non-acid-generating, thickened tailings to support six boreal tree species during two growing seasons. One treatment was thickened tailings alone fertilized with inorganic N, P, and K fertilizer or chicken () manure. A thin layer of overburden topsoil was used to cover the tailings and was compared with topsoil alone, where normal tree growth was expected. Two amendments were also tested: overburden topsoil and vermicompost from food wastes. The presence of alkaline thickened tailings under the thin layer of acidic topsoil had a positive effect on tree height and root biomass (broadleaved and jack pine [ Lamb.]) by increasing topsoil pH and available Ca concentrations, which decreased Al, Zn, and Mn phytoavailability to trees; however, root contact with the tailings also increased their Cu concentrations. In thickened tailings that were mixed with topsoil, C/N ratios increased along the experiment from 21 to 40, a value where N immobilization by microorganisms occurred, as suggested by low N concentrations in tree tissues. In consequence, tree height growth (broadleaved) and biomass (conifers) were reduced. Amendment with compost raised the electrical conductivity (3.4 dS cm) to thresholds limiting broadleaved survival, while conifers showed a generalized decrease in biomass production. No trace metal contamination of the trees occurred in the mixtures, probably due to the near-neutral pH conferred by the tailings. PMID:23673827

  19. Acid neutralization mechanisms and metal release in mine tailings: a laboratory column experiment

    NASA Astrophysics Data System (ADS)

    Jurjovec, Jasna; Ptacek, Carol J.; Blowes, David W.

    2002-05-01

    Mining and milling of base metal ore deposits can result in the release of metals to the environment. When sulfide minerals contained in mine tailings are exposed to oxygen and water, they oxidize and dissolve. Two principal antagonistic geochemical processes affect the migration of dissolved metals in tailings impoundments: sulfide oxidation and acid neutralization. This study focuses on acid neutralization reactions occurring in the saturated zone of tailings impoundments. To simulate conditions prevailing in many tailings impoundments, 0.1 mol/L sulfuric acid was passed continuously through columns containing fresh, unoxidized tailings, collected at Kidd Creek metallurgical site. The results of this column experiment represent a detailed temporal observation of pH, Eh, and metal concentrations. The results are consistent with previous field observations, which suggest that a series of mineral dissolution-precipitation reactions control pH and metal mobility. Typically, the series consists of carbonate minerals, Al and Fe(III) hydroxides, and aluminosilicates. In the case of Kidd Creek tailings, the dissolution series consists of ankerite-dolomite, siderite, gibbsite, and aluminosilicates. In the column experiment, three distinct pH plateaus were observed: 5.7, 4.0, and 1.3. The releases of trace elements such as Cd, Co, Cr, Cu, Li, Ni, Pb, V, and Zn were observed to be related to the pH buffering zones. High concentrations of Zn, Ni, and Co were observed at the first pH plateau (pH 5.7), whereas Cd, Cr, Pb, As, V, and Al were released as the pH of the pore water decreased to 4.0 or less.

  20. Single Conformation Spectroscopy of Suberoylanilide Hydroxamic Acid: a Molecule Bites its Tail

    NASA Astrophysics Data System (ADS)

    Zhang, Di; Dean, Jacob; Zwier, Timothy S.

    2012-06-01

    Suberoylanilide hydroxamic acid (C_6H_5NHCO(CH_2)_6CONHOH, SAHA) is a histone deacetylase inhibitor approved by the FDA for the treatment of cutaneous T-cell lymphoma. With one hydrogen bonding group adjacent to ring and the other at the end of a long C_6 hydrocarbon tail, SAHA possesses an interesting potential energy landscape to be probed by single-conformation methods. A large number of extended structures favored by entropy are offset by a few structures in which head-to-tail or tail-to-head H-bonds close a large loop between the two groups separated by the C_6 chain. We use laser desorption to bring SAHA into the gas phase and cool it in a supersonic expansion before interrogation with resonant two-photon ionization. Single-conformation UV spectra in the S_0-S_1 region and infrared spectra in the hydride stretch region were recorded using IR-UV hole-burning and resonant ion-dip infrared (RIDIR) spectroscopies, respectively. Four different conformers were observed and spectroscopically characterized. Comparison of the experimental IR spectra with density functional theory (DFT) calculations leads to assignments for two of the major conformers, which adopt head-to-tail and tail-to-head binding patterns. The implication of the observed structures for the folding landscape and configuration preference of SAHA will be discussed.

  1. Newly formed mRNA lacking polyadenylic acid enters the cytoplasm and the polyribosomes but has a shorter half-life in the absence of polyadenylic acid

    SciTech Connect

    Zeevi, M.; Nevins, J.R.; Darnell, J.E. Jr.

    1982-05-01

    Labeled adenovirus type 2 nuclear RNA molecules from cells treated with 3'-deoxyadenosine (3'dA) were earlier reported to lack polyadenylic acid (poly(A)), but to be correctly spliced in the nucleus. The authors found that the shortened mRNA molecules, lacking poly(A), can also be found in the cytoplasm of 3'dA-treated cells in association with the polyribosomes. In addition, the accumulation of labeled, nuclear adenovirus-specific RNA complementary to early regions 1a, 1b, and 2 of the adenovirus genome was approximately equal in 3'dA-treated and control cells. At the initial appearance of newly labeled adenovirus type 2 RNA (10 min) in the cytoplasm, there was one-half as much labeled RNA in 3'dA-treated as in the control. However, control cells accumulated additional mRNA in the cytoplasm very rapidly in the first 40 min of labeling, whereas the 3'dA-treated cells did not. Therefore, it appears that the correctly spliced, poly(A)/sup -/ mRNa molecules that are labeled in the presence of 3'dA can be transported from the nucleus with nearly the same frequency and the same exit time as in control cells and can be translated in the cytoplasm but have a much shorter half-life than the poly(A)/sup +/ mRNa molecules from control infected cells. From these results it is suggested that the role of poly(A) may be entirely to increase the longevity of cytoplasmic mRNA.

  2. Microbial diversity at the moderate acidic stage in three different sulfidic mine tailings dumps generating acid mine drainage.

    PubMed

    Korehi, Hananeh; Blöthe, Marco; Schippers, Axel

    2014-11-01

    In freshly deposited sulfidic mine tailings the pH is alkaline or circumneutral. Due to pyrite or pyrrhotite oxidation the pH is dropping over time to pH values <3 at which acidophilic iron- and sulfur-oxidizing prokaryotes prevail and accelerate the oxidation processes, well described for several mine waste sites. The microbial communities at the moderate acidic stage in mine tailings are only scarcely studied. Here we investigated the microbial diversity via 16S rRNA gene sequence analysis in eight samples (pH range 3.2-6.5) from three different sulfidic mine tailings dumps in Botswana, Germany and Sweden. In total 701 partial 16S rRNA gene sequences revealed a divergent microbial community between the three sites and at different tailings depths. Proteobacteria and Firmicutes were overall the most abundant phyla in the clone libraries. Acidobacteria, Actinobacteria, Bacteroidetes, and Nitrospira occurred less frequently. The found microbial communities were completely different to microbial communities in tailings at

  3. A Paradigm Shift for the Amino Acid Editing Mechanism of Human Cytoplasmic Leucyl-tRNA Synthetase†

    PubMed Central

    Joy Pang, Yan Ling; Martinis, Susan A.

    2010-01-01

    Leucyl-tRNA synthetase (LeuRS) has been identified as a target for a novel class of boron-containing small molecules that bind to its editing active site. When the 3′ end of tRNALeu binds to the editing active site, the boron crosslinks to the cis diols of its terminal ribose. The crosslinked RNA-protein complex blocks the overall aminoacylation activity of the enzyme. Similar to other LeuRSs, the human cytoplasmic enzyme (hscLeuRS) editing active site resides in a discrete domain called the connective polypeptide 1 domain (CP1), where mischarged tRNA binds for hydrolysis of the noncognate amino acid. The editing site of hscLeuRS includes a highly conserved threonine discriminator and universally conserved aspartic acid that were mutationally characterized. Substitution of the threonine residue to alanine uncoupled specificity similar to other LeuRSs. However, the introduction of bulky residues in the amino acid binding pocket failed to block deacylation of tRNA, indicating that the architecture of the amino acid binding pocket is different compared to other characterized LeuRSs. In addition, mutation of the universally conserved aspartic acid abolished tRNALeu deacylation. Surprisingly though, this editing-defective hscLeuRS maintained fidelity. It is possible that an alternate editing mechanism may have been activated upon failure of the post-transfer editing active site. PMID:19702327

  4. Quantitative Microbial Community Analysis of Three Different Sulfidic Mine Tailing Dumps Generating Acid Mine Drainage▿

    PubMed Central

    Kock, Dagmar; Schippers, Axel

    2008-01-01

    The microbial communities of three different sulfidic and acidic mine waste tailing dumps located in Botswana, Germany, and Sweden were quantitatively analyzed using quantitative real-time PCR (Q-PCR), fluorescence in situ hybridization (FISH), catalyzed reporter deposition-FISH (CARD-FISH), Sybr green II direct counting, and the most probable number (MPN) cultivation technique. Depth profiles of cell numbers showed that the compositions of the microbial communities are greatly different at the three sites and also strongly varied between zones of oxidized and unoxidized tailings. Maximum cell numbers of up to 109 cells g−1 dry weight were determined in the pyrite or pyrrhotite oxidation zones, whereas cell numbers in unoxidized tailings were significantly lower. Bacteria dominated over Archaea and Eukarya at all tailing sites. The acidophilic Fe(II)- and/or sulfur-oxidizing Acidithiobacillus spp. dominated over the acidophilic Fe(II)-oxidizing Leptospirillum spp. among the Bacteria at two sites. The two genera were equally abundant at the third site. The acidophilic Fe(II)- and sulfur-oxidizing Sulfobacillus spp. were generally less abundant. The acidophilic Fe(III)-reducing Acidiphilium spp. could be found at only one site. The neutrophilic Fe(III)-reducing Geobacteraceae as well as the dsrA gene of sulfate reducers were quantifiable at all three sites. FISH analysis provided reliable data only for tailing zones with high microbial activity, whereas CARD-FISH, Q-PCR, Sybr green II staining, and MPN were suitable methods for a quantitative microbial community analysis of tailings in general. PMID:18586975

  5. Quantitative microbial community analysis of three different sulfidic mine tailing dumps generating acid mine drainage.

    PubMed

    Kock, Dagmar; Schippers, Axel

    2008-08-01

    The microbial communities of three different sulfidic and acidic mine waste tailing dumps located in Botswana, Germany, and Sweden were quantitatively analyzed using quantitative real-time PCR (Q-PCR), fluorescence in situ hybridization (FISH), catalyzed reporter deposition-FISH (CARD-FISH), Sybr green II direct counting, and the most probable number (MPN) cultivation technique. Depth profiles of cell numbers showed that the compositions of the microbial communities are greatly different at the three sites and also strongly varied between zones of oxidized and unoxidized tailings. Maximum cell numbers of up to 10(9) cells g(-1) dry weight were determined in the pyrite or pyrrhotite oxidation zones, whereas cell numbers in unoxidized tailings were significantly lower. Bacteria dominated over Archaea and Eukarya at all tailing sites. The acidophilic Fe(II)- and/or sulfur-oxidizing Acidithiobacillus spp. dominated over the acidophilic Fe(II)-oxidizing Leptospirillum spp. among the Bacteria at two sites. The two genera were equally abundant at the third site. The acidophilic Fe(II)- and sulfur-oxidizing Sulfobacillus spp. were generally less abundant. The acidophilic Fe(III)-reducing Acidiphilium spp. could be found at only one site. The neutrophilic Fe(III)-reducing Geobacteraceae as well as the dsrA gene of sulfate reducers were quantifiable at all three sites. FISH analysis provided reliable data only for tailing zones with high microbial activity, whereas CARD-FISH, Q-PCR, Sybr green II staining, and MPN were suitable methods for a quantitative microbial community analysis of tailings in general. PMID:18586975

  6. Effect of fumaric acid, its dimethylester, and topical antipsoriatic drugs on epidermal differentiation in the mouse tail model.

    PubMed

    Sebök, B; Szabados, T; Kerényi, M; Schneider, I; Mahrle, G

    1996-01-01

    Fumaric acid, fumaric acid dimethylester, and the dithranol derivative C4-lactone were studied in the mouse tail test to evaluate their effects on epidermal cell differentiation compared with other topical antipsoriatic drugs, such as betamethasone, calcipotriol, and dithranol. Mouse tails were treated for 2 weeks and longitudinal histological sections prepared of the tail skin. The length of the orthokeratotic regions (stratum granulosum) was measured on 10 sequential scales per tail and expressed as percentage of the full length of the scale. In addition, epidermal thickness was measured and the efficacy of the various compounds evaluated. In comparison to 2% salicylic acid ointment, all tested compounds except fumaric acid significantly (p < or = 0.05) increased the proportion of the orthokeratotic region. C4-lactone and calcipotriol were less effective than dithranol, fumaric acid dimethylester only moderately influenced cell differentiation, and betamethasone showed the least potent effect. Dithranol was the most potent substance inducing orthokeratosis without increasing epidermal thickness. PMID:8722603

  7. Small Drops Get Fat: Unexpected Fatty Acid in Cytoplasmic Lipid Droplets.

    PubMed

    Thurnher, Martin

    2016-06-23

    In a model of transcellular lipid biosynthesis, Guijas et al. (2016), in this issue of Cell Chemical Biology, demonstrate that lipid droplet-containing "foamy" monocytes unexpectedly accumulate 16:1n9-palmitoleic acid, which has anti-inflammatory function in vitro and in vivo. This uncommon positional isomer of 16:1n7-palmitoleic acid represents a candidate biomarker for early cardiovascular disease detection. PMID:27341429

  8. Oil sands thickened froth treatment tailings exhibit acid rock drainage potential during evaporative drying.

    PubMed

    Kuznetsov, Petr; Kuznetsova, Alsu; Foght, Julia M; Siddique, Tariq

    2015-02-01

    Bitumen extraction from oil sands ores after surface mining produces different tailings waste streams: 'froth treatment tailings' are enriched in pyrite relative to other streams. Tailings treatment can include addition of organic polymers to produce thickened tailings (TT). TT may be further de-watered by deposition into geotechnical cells for evaporative drying to increase shear strength prior to reclamation. To examine the acid rock drainage (ARD) potential of TT, we performed predictive analyses and laboratory experiments on material from field trials of two types of thickened froth treatment tailings (TT1 and TT2). Acid-base accounting (ABA) of initial samples showed that both TT1 and TT2 initially had net acid-producing potential, with ABA values of -141 and -230 t CaCO₃ equiv. 1000 t(-1) of TT, respectively. In long-term kinetic experiments, duplicate ~2-kg samples of TT were incubated in shallow trays and intermittently irrigated under air flow for 459 days to simulate evaporative field drying. Leachates collected from both TT samples initially had pH~6.8 that began decreasing after ~50 days (TT2) or ~250 days (TT1), stabilizing at pH~2. Correspondingly, the redox potential of leachates increased from 100-200 mV to 500-580 mV and electrical conductivity increased from 2-5 dS m(-1) to 26 dS m(-1), indicating dissolution of minerals during ARD. The rapid onset and prolonged ARD observed with TT2 is attributed to its greater pyrite (13.4%) and lower carbonate (1.4%) contents versus the slower onset of ARD in TT1 (initially 6.0% pyrite and 2.5% carbonates). 16S rRNA gene pyrosequencing analysis revealed rapid shift in microbial community when conditions became strongly acidic (pH~2) favoring the enrichment of Acidithiobacillus and Sulfobacillus bacteria in TT. This is the first report showing ARD potential of TT and the results have significant implications for effective management of pyrite-enriched oil sands tailings streams/deposits. PMID:25306090

  9. Cytoplasmic Delivery of Liposomal Contents Mediated by an Acid-Labile Cholesterol-Vinyl Ether-PEG Conjugate

    PubMed Central

    Boomer, Jeremy A.; Qualls, Marquita M.; Inerowicz, H. Dorota; Haynes, Robert H.; Patri, G.V. Srilaksmi; Kim, Jong-Mok; Thompson, David H.

    2009-01-01

    An acid-cleavable PEG lipid, 1′-(4′-cholesteryloxy-3′-butenyl)-ω-methoxy-polyethylene[112] glycolate (CVEP), has been developed that produces stable liposomes when dispersed as a minor component (0.5–5 mol%) in 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). Cleavage of CVEP at mildly acidic pH’s results in dePEGylation of the latently fusogenic DOPE liposomes, thereby triggering the onset of contents release. This paper describes the synthesis of CVEP via a six step sequence starting from the readily available precursors 1,4-butanediol, cholesterol, and mPEG acid. The hydrolysis rates and release kinetics from CVEP:DOPE liposome dispersions as a function of CVEP loading, as well as the cryogenic transmission electron microscopy and pH-dependent monolayer properties of 9:91 CVEP:DOPE mixtures, also are reported. When folate-receptor positive KB cells were exposed to calcein-loaded 5:95 CVEP:DOPE liposomes containing 0.1 mol% folate-modified 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-polyethylene[76] glycolamide (folate-PEG-DSPE), efficient delivery of the calcein cargo to the cytoplasm of the cells was observed as determined by fluorescence microscopy and flow cytometry. Fluorescence resonance energy transfer analysis of lipid mixing in these cells was consistent with membrane-membrane fusion between the liposome and endosomal membranes. PMID:19072698

  10. Hypobaric bacteriology: growth, cytoplasmic membrane polarization and total cellular fatty acids in Escherichia coli and Bacillus subtilis

    NASA Astrophysics Data System (ADS)

    Pokorny, N. J.; Boulter-Bitzer, J. I.; Hart, M. M.; Storey, L.; Lee, H.; Trevors, J. T.

    2005-10-01

    Escherichia coli JM109 (Gram-negative) and Bacillus subtilis (Gram-positive) were grown under hypobaric conditions for 19 days at 25 °C to study the effects of 33 and 67 kPa low pressures on selected physiological responses; growth, cytoplasmic membrane polarization (measure of cytoplasmic membrane fluidity) and total cellular fatty acids. In the first experiment, cytoplasmic membrane polarization in B. subtilis increased under both hypobaric conditions, indicating the membrane became more rigid or less fluid. This experiment was repeated and the effect of the hypobaric conditions was not evident as in the first experiment with B. subtilis. In addition, total cellular fatty acids analysis for B. subtilis showed that hypobaric conditions did not alter the ratio of saturated to unsaturated fatty acids. The cytoplasmic membrane remained in the same fluid state in hypobaric grown E. coli cell cultures as in the 101 kPa ambient control cells in both experiments. However, the saturated to unsaturated ratios were altered in E. coli under hypobaric conditions. It is important to note the ratios for E. coli were less than 1, while the ratios for Bacillus were in the 28 50 range. Growth of both species was also measured by colony forming units at the termination of the 19 day experiment. Both bacterial species were capable of growth under hypobaric conditions and no distinct trend emerged as to the effect of hypobaric pressure on bacterial growth and cytoplasmic membrane fluidity.

  11. Amino acid residues 201-205 in C-terminal acidic tail region plays a crucial role in antibacterial activity of HMGB1

    PubMed Central

    2009-01-01

    Background Antibacterial activity is a novel function of high-mobility group box 1 (HMGB1). However, the functional site for this new effect is presently unknown. Methods and Results In this study, recombinant human HMGB1 A box and B box (rHMGB1 A box, rHMGB1 B box), recombinant human HMGB1 (rHMGB1) and the truncated C-terminal acidic tail mutant (tHMGB1) were prepared by the prokaryotic expression system. The C-terminal acidic tail (C peptide) was synthesized, which was composed of 30 amino acid residues. Antibacterial assays showed that both the full length rHMGB1 and the synthetic C peptide alone could efficiently inhibit bacteria proliferation, but rHMGB1 A box and B box, and tHMGB1 lacking the C-terminal acidic tail had no antibacterial function. These results suggest that C-terminal acidic tail is the key region for the antibacterial activity of HMGB1. Furthermore, we prepared eleven different deleted mutants lacking several amino acid residues in C-terminal acidic tail of HMGB1. Antibacterial assays of these mutants demonstrate that the amino acid residues 201-205 in C-terminal acidic tail region is the core functional site for the antibacterial activity of the molecule. Conclusion In sum, these results define the key region and the crucial site in HMGB1 for its antibacterial function, which is helpful to illustrating the antibacterial mechanisms of HMGB1. PMID:19751520

  12. Laboratory evaluation of limestone and lime neutralization of acidic uranium mill tailings solution. Progress report

    SciTech Connect

    Opitz, B.E.; Dodson, M.E.; Serne, R.J.

    1984-02-01

    Experiments were conducted to evaluate a two-step neutralization scheme for treatment of acidic uranium mill tailings solutions. Tailings solutions from the Lucky Mc Mill and Exxon Highland Mill, both in Wyoming, were neutralized with limestone, CaCO/sub 3/, to an intermediate pH of 4.0 or 5.0, followed by lime, Ca(OH)/sub 2/, neutralization to pH 7.3. The combination limestone/lime treatment methods, CaCO/sub 3/ neutralization to pH 4 followed by neutralization with Ca(OH)/sub 2/ to pH 7.3 resulted in the highest quality effluent solution with respect to EPA's water quality guidelines. The combination method is the most cost-effective treatment procedure tested in our studies. Neutralization experiments to evaluate the optimum solution pH for contaminant removal were performed on the same two tailings solutions using only lime Ca(OH)/sub 2/ as the neutralizing agent. The data indicate solution neutralization above pH 7.3 does not significantly increase removal of pH dependent contaminants from solution. Column leaching experiments were performed on the neutralized sludge material (the precipitated solid material which forms as the acidic tailings solutions are neutralized to pH 4 or above). The sludges were contacted with laboratory prepared synthetic ground water until several effluent pore volumes were collected. Effluent solutions were analyzed for macro ions, trace metals and radionuclides in an effort to evaluate the long term effectiveness of attenuating contaminants in sludges formed during solution neutralization. Neutralized sludge leaching experiments indicate that Ca, Na, Mg, Se, Cl, and SO/sub 4/ are the only constituents which show solution concentrations significantly higher than the synthetic ground water in the early pore volumes of long-term leaching studies.

  13. Evolution of plant colonization in acid and alkaline mine tailing ponds after amendments and microorganisms application

    NASA Astrophysics Data System (ADS)

    Acosta, Jose Alberto; Faz, Ángel; Kabas, Sebla; Zornoza, Raúl; Martínez-Martínez, Silvia

    2014-05-01

    Intense mining activities in the past were carried out in Cartagena-La Unión mining district, SE Spain, and caused excessive accumulation of toxic metals in tailing ponds which poses a high environmental and ecological risk. One of the remediation options gaining considerable interest in recent years is the in situ immobilization of metals. A corresponding reduction in the plant-available metal fraction allows re-vegetation and ecosystem restoration of the heavily contaminated sites. In addition, the use of microorganisms to improve the soil condition is a new tool used to increase spontaneous plant colonization. The aim of this research was to assess the effect of amendments (pig manure, sewage sludge, and lime) and microorganisms on plant cover establishment, as a consequence of metal immobilization and the improvement of soil properties. The study was carried out in two mine ponds (acid and alkaline). Twenty seven square field plots, each one consisting of 4 m2, were located in each pond. Four different doses of microorganism (0 ml, 20 ml, 100 ml and 200 ml of microorganism solution in each plot) and one dose of pig manure (5 kg per plot), sewage sludge (4 kg per plot) and lime (22 kg per plot) were used. Organic amendment doses were calculated according to European nitrogen legislations, and lime dose was calculated according with the potential acid production through total sulphur oxidation. Three replicates of each treatment (organic amendment + lime + microorganism dose 0, 1, 2, or 3) and control soil (with no amendments) were carried out. Plots were left to the semi-arid climate conditions after the addition of amendments to simulate real potential applications of the results. Identification of plant species and biodiversity was determined on each plot, after 2, 4, 6 and 8 months of amendment addition. The results showed that, in those plots without application of microorganism, 8 months after applications the number of species and individuals of each

  14. Co-ordination between membrane phospholipid synthesis and accelerated biosynthesis of cytoplasmic ribonucleic acid and protein

    PubMed Central

    Tata, J. R.

    1970-01-01

    1. The rate of synthesis of membrane phospholipid was studied in rat liver and seminal vesicles by following the incorporation of [32P]orthophosphate, [14C]choline and [14C]glycerol. Particular emphasis was laid on the endoplasmic reticulum, which was fractionated into smooth microsomal membranes, heavy rough membranes, light rough membranes and free polyribosomes. 2. Phospholipid labelling patterns suggested a heterogeneity in the synthesis and turnover of the different lipid moieties of smooth and rough endoplasmic membranes. The major phospholipids, phosphatidylcholine and phosphatidylethanolamine, were labelled relatively rapidly with 32P over a short period of time whereas incorporation of radioisotope into the minor phospholipids, sphingomyelin, lysolecithin and phosphatidylinositol proceeded slowly but over a longer period of time. 3. The incorporation of orotic acid into RNA and labelled amino acids into protein of the four submicrosomal fractions was also studied. 4. Rapid growth of the liver was induced by the administration of growth hormone and tri-iodothyronine to hypophysectomized and thyroidectomized rats and by partial hepatectomy. Growth of seminal vesicles of castrated rats was stimulated with testosterone propionate. 5. The rate of labelling of membrane phospholipids was enhanced in all major subcellular particulate fractions (nuclear, mitochondrial and microsomal) during induced growth. However, it was in the rough endoplasmic reticulum that the accumulation of phospholipids, RNA and protein was most marked. The effect of hormone administration was also to accelerate preferentially the labelling with 32P of sphingomyelin relative to that of phosphatidylcholine or phosphatidylethanolamine. 6. Time-course analyses showed that, in all four growth systems studied, the enhancement of the rate of membrane phospholipid synthesis coincided with the rather abrupt increase in the synthesis of RNA and protein of the rough endoplasmic reticulum. Growth

  15. Efficient degradation of Acid Orange 7 in aqueous solution by iron ore tailing Fenton-like process.

    PubMed

    Zheng, Jianming; Gao, Zhanqi; He, Huan; Yang, Shaogui; Sun, Cheng

    2016-05-01

    An effective method based on iron ore tailing Fenton-like process was studied for removing an azo dye, Acid Orange 7 (AO7) in aqueous solution. Five tailings were characterized by X-ray fluorescence spectroscope (XFS), Brunner-Emmet-Teller (BET) measurement, and Scanning Electron Microscope (SEM). The result of XFS showed that Fe, Si and Ca were the most abundant elements and some toxic heavy metals were also present in the studied tailings. The result of BET analysis indicated that the studied tailings had very low surface areas (0.64-5.68 m(2) g(-1)). The degradation efficiencies of AO7 were positively correlated with the content of iron oxide and cupric oxide, and not related with the BET surface area of the tailings. The co-existing metal elements, particularly Cu, might accelerate the heterogeneous Fenton-like reaction. The effects of other parameters on heterogeneous Fenton-like degradation of AO7 by a converter slag iron tailing (tailing E) which contains highest iron oxide were also investigated. The tailing could be reused 10 times without significant decrease of the catalytic capacity. Very low amount of iron species and almost undetectable toxic elements were leached in the catalytic degradation of AO7 by the tailing E. The reaction products were identified by gas chromatography-mass spectrometry and a possible pathway of AO7 degradation was proposed. This study not only provides an effective method for removing azo dyes in polluted water by employing waste tailings as Fenton-like catalysts, but also uses waste tailings as the secondary resource. PMID:26891355

  16. Metabolism of branched-chain amino acids in leg muscles from tail-cast suspended intact and adrenalectomized rats

    NASA Technical Reports Server (NTRS)

    Jaspers, Stephen R.; Henriksen, Erik; Jacob, Stephan; Tischler, Marc E.

    1989-01-01

    The effects of muscle unloading, adrenalectomy, and cortisol treatment on the metabolism of branched-chain amino acids in the soleus and extensor digitorum longus of tail-cast suspended rats were investigated using C-14-labeled lucine, isoleucine, and valine in incubation studies. It was found that, compared to not suspended controls, the degradation of branched-chain amino acids in hind limb muscles was accelerated in tail-cast suspended rats. Adrenalectomy was found to abolish the aminotransferase flux and to diminish the dehydrogenase flux in the soleus. The data also suggest that cortisol treatment increases the rate of metabolism of branched-chain amino acids at the dehydrogenase step.

  17. Nutritional restriction and acid-base balance in white-tailed deer

    USGS Publications Warehouse

    DelGiudice, G.D.; Mech, L.D.; Seal, U.S.

    1994-01-01

    We examined the effect of progressive nutritional restriction on acid-base balance in seven captive, adult white-tailed deer (Odocoileus virginianus) from 4 February to 5 May 1988 in north central Minnesota (USA). Metabolic acidosis was indicated by low mean blood pH (7.25 to 7.33) in deer throughout the study. Mean urinary pH values declined (P = 0.020) from a mean (+SE) baseline of 8.3 +0.1 to 6.7 + 0.3 as restriction progressed. Acidemia and aciduria were associated with significant variations in mean blood CO2 (P = 0.006) and pO2 (P = 0.032), serum potassium (P = 0.004) concentrations, and with a significant (P = 0.104) handling date times group interaction in urinary potassium:creatinine values. Mean bicarbonate:carbonic acid ratios were consistently below 20:1 during nutritional restriction. Mean packed cell volume increased (P = 0.019) and serum total protein decreased (P = 0.001); thus there was evidence for progressive dehydration and net protein catabolism, respectively. Blood pCO2, serum sodium, and urinary sodium:creatinine were stable throughout the study. We propose that acidosis and aciduria are metabolic complications associated with nutritional restriction of white-tailed deer.

  18. Changes in the Cytoplasmic Composition of Amino Acids and Proteins Observed in Staphylococcus aureus during Growth under Variable Growth Conditions Representative of the Human Wound Site

    PubMed Central

    Alreshidi, Mousa M.; Dunstan, R. Hugh; Gottfries, Johan; Macdonald, Margaret M.; Crompton, Marcus J.; Ang, Ching-Seng; Williamson, Nicholas A.; Roberts, Tim K.

    2016-01-01

    Staphylococcus aureus is an opportunistic pathogen responsible for a high proportion of nosocomial infections. This study was conducted to assess the bacterial responses in the cytoplasmic composition of amino acids and ribosomal proteins under various environmental conditions designed to mimic those on the human skin or within a wound site: pH6-8, temperature 35–37°C, and additional 0–5% NaCl. It was found that each set of environmental conditions elicited substantial adjustments in cytoplasmic levels of glutamic acid, aspartic acid, proline, alanine and glycine (P< 0.05). These alterations generated characteristic amino acid profiles assessed by principle component analysis (PCA). Substantial alterations in cytoplasmic amino acid and protein composition occurred during growth under conditions of higher salinity stress implemented via additional levels of NaCl in the growth medium. The cells responded to additional NaCl at pH 6 by reducing levels of ribosomal proteins, whereas at pH 8 there was an upregulation of ribosomal proteins compared with the reference control. The levels of two ribosomal proteins, L32 and S19, remained constant across all experimental conditions. The data supported the hypothesis that the bacterium was continually responding to the dynamic environment by modifying the proteome and optimising metabolic homeostasis. PMID:27442022

  19. Response of key soil parameters during compost-assisted phytostabilization in extremely acidic tailings: effect of plant species.

    PubMed

    Solís-Dominguez, Fernando A; White, Scott A; Hutter, Travis Borrillo; Amistadi, Mary Kay; Root, Robert A; Chorover, Jon; Maier, Raina M

    2012-01-17

    Phytostabilization of mine tailings acts to mitigate both eolian dispersion and water erosion events which can disseminate barren tailings over large distances. This technology uses plants to establish a vegetative cover to permanently immobilize contaminants in the rooting zone, often requiring addition of an amendment to assist plant growth. Here we report the results of a greenhouse study that evaluated the ability of six native plant species to grow in extremely acidic (pH ∼ 2.5) metalliferous (As, Pb, Zn: 2000-3000 mg kg(-1)) mine tailings from Iron King Mine Humboldt Smelter Superfund site when amended with a range of compost concentrations. Results revealed that three of the six plant species tested (buffalo grass, mesquite, and catclaw acacia) are good candidates for phytostabilization at an optimum level of 15% compost (w/w) amendment showing good growth and minimal shoot accumulation of metal(loid)s. A fourth candidate, quailbush, also met all criteria except for exceeding the domestic animal toxicity limit for shoot accumulation of zinc. A key finding of this study was that the plant species that grew most successfully on these tailings significantly influenced key tailings parameters; direct correlations between plant biomass and both increased tailings pH and neutrophilic heterotrophic bacterial counts were observed. We also observed decreased iron oxidizer counts and decreased bioavailability of metal(loid)s mainly as a result of compost amendment. Taken together, these results suggest that the phytostabilization process reduced tailings toxicity as well as the potential for metal(loid) mobilization. This study provides practical information on plant and tailings characteristics that is critically needed for successful implementation of assisted phytostabilization on acidic, metalliferous mine tailings sites. PMID:22191663

  20. Response of Key Soil Parameters During Compost-Assisted Phytostabilization in Extremely Acidic Tailings: Effect of Plant Species

    PubMed Central

    Solís-Dominguez, Fernando A.; White, Scott A.; Hutter, Travis Borrillo; Amistadi, Mary Kay; Root, Robert A.; Chorover, Jon; Maier, Raina M.

    2012-01-01

    Phytostabilization of mine tailings acts to mitigate both eolian dispersion and water erosion events which can disseminate barren tailings over large distances. This technology uses plants to establish a vegetative cover to permanently immobilize contaminants in the rooting zone, often requiring addition of an amendment to assist plant growth. Here we report the results of a greenhouse study that evaluated the ability of six native plant species to grow in extremely acidic (pH ~ 2.5) metalliferous (As, Pb, Zn: 2000–3000 mg kg−1) mine tailings from Iron King Mine Humboldt Smelter Superfund site when amended with a range of compost concentrations. Results revealed that three of the six plant species tested (buffalo grass, mesquite, and catclaw acacia) are good candidates for phytostabilization at an optimum level of 15% compost (w/w) amendment showing good growth and minimal shoot accumulation of metal(loid)s. A fourth candidate, quailbush, also met all criteria except for exceeding the domestic animal toxicity limit for shoot accumulation of zinc. A key finding of this study was that the plant species that grew most successfully on these tailings significantly influenced key tailings parameters; direct correlations between plant biomass and both increased tailings pH and neutrophilic heterotrophic bacterial counts were observed. We also observed decreased iron oxidizer counts and decreased bioavailability of metal(loid)s mainly as a result of compost amendment. Taken together, these results suggest that the phytostabilization process reduced tailings toxicity as well as the potential for metal(loid) mobilization. This study provides practical information on plant and tailings characteristics that is critically needed for successful implementation of assisted phytostabilization on acidic, metalliferous mine tailings sites. PMID:22191663

  1. Functions of the Membrane-Associated and Cytoplasmic Malate Dehydrogenases in the Citric Acid Cycle of Corynebacterium glutamicum

    PubMed Central

    Molenaar, Douwe; van der Rest, Michel E.; Drysch, André; Yücel, Raif

    2000-01-01

    Like many other bacteria, Corynebacterium glutamicum possesses two types of l-malate dehydrogenase, a membrane-associated malate:quinone oxidoreductase (MQO; EC 1.1.99.16) and a cytoplasmic malate dehydrogenase (MDH; EC 1.1.1.37) The regulation of MDH and of the three membrane-associated dehydrogenases MQO, succinate dehydrogenase (SDH), and NADH dehydrogenase was investigated. MQO, MDH, and SDH activities are regulated coordinately in response to the carbon and energy source for growth. Compared to growth on glucose, these activities are increased during growth on lactate, pyruvate, or acetate, substrates which require high citric acid cycle activity to sustain growth. The simultaneous presence of high activities of both malate dehydrogenases is puzzling. MQO is the most important malate dehydrogenase in the physiology of C. glutamicum. A mutant with a site-directed deletion in the mqo gene does not grow on minimal medium. Growth can be partially restored in this mutant by addition of the vitamin nicotinamide. In contrast, a double mutant lacking MQO and MDH does not grow even in the presence of nicotinamide. Apparently, MDH is able to take over the function of MQO in an mqo mutant, but this requires the presence of nicotinamide in the growth medium. It is shown that addition of nicotinamide leads to a higher intracellular pyridine nucleotide concentration, which probably enables MDH to catalyze malate oxidation. Purified MDH from C. glutamicum catalyzes oxaloacetate reduction much more readily than malate oxidation at physiological pH. In a reconstituted system with isolated membranes and purified MDH, MQO and MDH catalyze the cyclic conversion of malate and oxaloacetate, leading to a net oxidation of NADH. Evidence is presented that this cyclic reaction also takes place in vivo. As yet, no phenotype of an mdh deletion alone was observed, which leaves a physiological function for MDH in C. glutamicum obscure. PMID:11092846

  2. Faceted fatty acid vesicles formed from single-tailed perfluorinated surfactants.

    PubMed

    Zhang, Juan; Xu, Guiying; Song, Aixin; Wang, Lin; Lin, Meiqin; Dong, Zhaoxia; Yang, Zihao

    2015-09-28

    The aggregation behavior and rheological properties of two mixtures of perfluorononanoic acid (PFNA)/NaOH and perfluorodecanoic acid (PFDA)/NaOH were investigated in aqueous solutions. Interestingly, pH-sensitive polyhedral fatty acid vesicles were spontaneously formed in both systems, which were determined by freeze-fracture transmission electron microscopy (FF-TEM) measurements. Especially, a phase transition from faceted vesicles to the L3 phase with the increase of pH was observed in the PFNA/NaOH system while it was not observed in the PFDA/NaOH system. Differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS) measurements confirmed that the bilayers of the faceted vesicles were in the crystalline station indicating that the crystallization of fluorocarbon chains was the main driving force for their formation. Besides, the two systems of faceted perfluorofatty acid vesicles exhibit interesting rheological properties, for instance, they showed high viscoelasticity and shear-thinning behaviour, and the elastic modulus (G') and viscous modulus (G'') of PFDA/NaOH vesicles were much higher than those of PFNA/NaOH vesicles. Conversely, the solution of the L3 phase with fluid bilayers did not present viscoelastic properties. Therefore, the viscoelastic properties of vesicles resulted from the crystalline fluorinated alkyl chains with high rigidity at room temperature and the dense packing of vesicles. As far as we know, such faceted fatty acid vesicles formed from single-tailed perfluorinated surfactants have been rarely reported. Our work successfully constructs polyhedral fatty acid vesicles and proposes their formation mechanism, which should be a great advance in the fundamental research of fatty acid vesicles. PMID:26252803

  3. Efficient inhibition of heavy metal release from mine tailings against acid rain exposure by triethylenetetramine intercalated montmorillonite (TETA-Mt).

    PubMed

    Gong, Beini; Wu, Pingxiao; Huang, Zhujian; Li, Yuanyuan; Yang, Shanshan; Dang, Zhi; Ruan, Bo; Kang, Chunxi

    2016-11-15

    The potential application of triethylenetetramine intercalated montmorillonite (TETA-Mt) in mine tailings treatment and AMD (acid mine drainage) remediation was investigated with batch experiments. The structural and morphological characteristics of TETA-Mt were analyzed with XRD, FTIR, DTG-TG and SEM. The inhibition efficiencies of TETA-Mt against heavy metal release from mine tailings when exposed to acid rain leaching was examined and compared with that of triethylenetetramine (TETA) and Mt. Results showed that the overall inhibition by TETA-Mt surpassed that by TETA or Mt for various heavy metal ions over an acid rain pH range of 3-5.6 and a temperature range of 25-40°C. When mine tailings were exposed to acid rain of pH 4.8 (the average rain pH of the mining site where the mine tailings were from), TETA-Mt achieved an inhibition efficiency of over 90% for Cu(2+), Zn(2+), Cd(2+) and Mn(2+) release, and 70% for Pb(2+) at 25°C. It was shown that TETA-Mt has a strong buffering capacity. Moreover, TETA-Mt was able to adsorb heavy metal ions and the adsorption process was fast, suggesting that coordination was mainly responsible. These results showed the potential of TETA-Mt in AMD mitigation, especially in acid rain affected mining area. PMID:27450331

  4. Glucocorticoid control of rat growth hormone gene expression: Effect on cytoplasmic messenger ribonucleic acid production and degradation

    SciTech Connect

    Gertz, B.J.; Gardner, D.G.; Baxter, J.D. )

    1987-12-01

    The effect of the glucocorticoid dexamethasone on the production and degradation of rat GH (rGH) cytoplasmic mRNA was studied in cultured rat pituitary tumor (GC) cells. The incorporation of (3H)uridine into both rGH cytoplasmic mRNA and the pyrimidine nucleotide precursor pool was determined in hormone-treated and control cells. From these measurements glucocorticoid effects on absolute production rates of rGH cytoplasmic mRNA were determined and compared to effects on rGH mRNA accumulation. Rat GH mRNA half-life was then calculated based on a first-order decay model. Rat GH mRNA half-life was also directly assayed by: (1) pulse-chase studies and (2) measuring the kinetics of decay of rGH mRNA in cells after transfer from serum-containing to hormone-deficient media. From these independent analyses rGH mRNA half-life estimates ranged from 28-55 h in different experiments. Within individual experiments there was little variability of rGH mRNA decay rates; glucocorticoids were found not to alter the stability of rGH cytoplasmic mRNA. Glucocorticoid induction of rGH cytoplasmic mRNA accumulation was accounted for solely on the basis of increased mRNA production.

  5. Trace metal mobilization from oil sands froth treatment thickened tailings exhibiting acid rock drainage.

    PubMed

    Kuznetsova, Alsu; Kuznetsov, Petr; Foght, Julia M; Siddique, Tariq

    2016-11-15

    Froth treatment thickened tailings (TT) are a waste product of bitumen extraction from surface-mined oil sands ores. When incubated in a laboratory under simulated moist oxic environmental conditions for ~450d, two different types of TT (TT1 and TT2) exhibited the potential to generate acid rock drainage (ARD) by producing acid leachate after 250 and 50d, respectively. We report here the release of toxic metals from TT via ARD, which could pose an environmental threat if oil sands TT deposits are not properly managed. Trace metal concentrations in leachate samples collected periodically revealed that Mn and Sr were released immediately even before the onset of ARD. Spikes in Co and Ni concentrations were observed both pre-ARD and during active ARD, particularly in TT1. For most elements measured (Fe, Cr, V, As, Cu, Pb, Zn, Cd, and Se), leaching was associated with ARD production. Though equivalent acidification (pH2) was achieved in leachate from both TT types, greater metal release was observed from TT2 where concentrations reached 10,000ppb for Ni, 5000ppb for Co, 3000ppb for As, 2000ppb for V, and 1000ppb for Cr. Generally, metal concentrations decreased in leachate with time during ARD and became negligible by the end of incubation (~450d) despite appreciable metals remaining in the leached TT. These results suggest that using TT for land reclamation purposes or surface deposition for volume reduction may unfavorably impact the environment, and warrants application of appropriate strategies for management of pyrite-enriched oil sands tailings streams. PMID:27443453

  6. Manganese ore tailing: optimization of acid leaching conditions and recovery of soluble manganese.

    PubMed

    Santos, Olívia de Souza Heleno; Carvalho, Cornélio de Freitas; Silva, Gilmare Antônia da; Santos, Cláudio Gouvêa Dos

    2015-01-01

    Manganese recovery from industrial ore processing waste by means of leaching with sulfuric acid was the objective of this study. Experimental conditions were optimized by multivariate experimental design approaches. In order to study the factors affecting leaching, a screening step was used involving a full factorial design with central point for three variables in two levels (2(3)). The three variables studied were leaching time, concentration of sulfuric acid and sample amount. The three factors screened were shown to be relevant and therefore a Doehlert design was applied to determine the best working conditions for leaching and to build the response surface. By applying the best leaching conditions, the concentrations of 12.80 and 13.64 %w/w of manganese for the global sample and for the fraction -44 + 37 μm, respectively, were found. Microbeads of chitosan were tested for removal of leachate acidity and recovering of soluble manganese. Manganese recovery from the leachate was 95.4%. Upon drying the leachate, a solid containing mostly manganese sulfate was obtained, showing that the proposed optimized method is efficient for manganese recovery from ore tailings. PMID:25284800

  7. Spatial and Temporal Analysis of the Microbial Community in the Tailings of a Pb-Zn Mine Generating Acidic Drainage ▿ †

    PubMed Central

    Huang, Li-Nan; Zhou, Wen-Hua; Hallberg, Kevin B.; Wan, Cai-Yun; Li, Jie; Shu, Wen-Sheng

    2011-01-01

    Analysis of spatial and temporal variations in the microbial community in the abandoned tailings impoundment of a Pb-Zn mine revealed distinct microbial populations associated with the different oxidation stages of the tailings. Although Acidithiobacillus ferrooxidans and Leptospirillum spp. were consistently present in the acidic tailings, acidophilic archaea, mostly Ferroplasma acidiphilum, were predominant in the oxidized zones and the oxidation front, indicating their importance to generation of acid mine drainage. PMID:21705549

  8. Comparison of the meat quality and fatty acid composition of traditional fat-tailed (Chall) and tailed (Zel) Iranian sheep breeds.

    PubMed

    Yousefi, Ali Reza; Kohram, Hamid; Zare Shahneh, Ahmad; Nik-khah, Ali; Campbell, Anna W

    2012-12-01

    The aim of this study was to compare the meat quality of a traditional fat-tailed breed, Chall, to a tailed Iranian sheep breed, Zel. Lambs were grazed on pasture until weaning, and then were finished until slaughter at 10-12 months. Meat quality traits were measured on the longissimus dorsi (LD) muscle. Zel lambs accumulated more intramuscular fat (IMF) (p<0.01) and had lower shear force and drip loss than Chall lambs (p<0.05). The meat color of Zel lambs was higher for both a* (p<0.001) and b* (p<0.01) compared to Chall lambs. Meat from Zel lambs was more tender (p<0.01) and more juicy (p<0.05) than Chall lambs. The PUFA:SFA fatty acid ratio (P:S) was higher (p<0.05) and the n-6:n-3 PUFA ratio was lower in Chall compared to Zel lambs (p<0.05). Overall, these results show that the eating quality of Zel lambs was better, but that this was at the cost of less favorable fatty acid profiles and poorer meat color. PMID:22652069

  9. Single amino acid substitutions influencing the folding pathway of the phage P22 tail spike endorhamnosidase.

    PubMed

    Yu, M H; King, J

    1984-11-01

    Temperature-sensitive mutations in the gene for the thermostable tail spike of phage P22 interyFere with the folding and subunit association pathway at the restrictive temperature but not with the activity or stability of the protein once matured. The local sites of these mutations and the mutant amino acid substitutions have been determined by DNA sequencing. Of 11 temperature-sensitive folding mutations, 3 were replacements of glycine residues by polar residues, and three were replacements of threonine residues by residues unable to form a side-chain H-bond. There were no proline replacements. Two of the temperature-sensitive sites in which threonine residues were replaced by isoleucine residues were homologous. These sequences probably maintain the correct local folding pathway at higher temperatures. The temperature-sensitive amino acid substitutions appear to destabilize a thermolabile intermediate in the wild-type folding pathway or to increase the rate of a competing off-pathway reaction. PMID:6387707

  10. Identification of an epitope within the Bovine herpesvirus 1 glycoprotein E cytoplasmic tail and use of a monoclonal antibody directed against the epitope for the differentiation between vaccinated and infected animals.

    PubMed

    Chowdhury, Shafiqul I

    2016-07-01

    We constructed a recombinant bovine herpesvirus type 1 triple mutant virus (BoHV-1 tmv) that lacks UL49.5 residues 30-32 and 80-96, gE cytoplasmic tail (gE CT) residues 452-575 and the entire 435bp long Us9 ORF. To develop a gE CT-specific blocking ELISA test that is necessary to distinguish the BoHV-1 tmv vaccinated calves from the wild-type (wt) virus-infected calves, a mouse monoclonal antibody (mAb) 2H8F3 was generated by using the Escherichia coli expressed gE CT residues 452-575. Further, by performing a PEPSCAN analysis of 12 mer overlapping peptides spanning the entire gE CT, the epitope sequence recognized by the mAb2H8F3 was mapped within the gE CT residues 499SDDDGPASN507. A blocking ELISA test was then developed for detecting antibodies in wild-type BoHV-1 infected calves against the gE CT epitope specified by 499SDDDGPASN507. The assay is based on the use of HRP conjugated mAb2H8F3 and the E. coli expressed gE CT protein as an indicator antibody and a coating antigen, respectively. In this assay, serum from entire gE-deleted and BoHV-1 tmv-infected calves scored negative, whereas serum from calves infected with BoHV-1 wt scored positive. Therefore, the gE CT-ELISA, based on the mAb2H8F3 and E. coli expressed gE CT protein, is suitable for differentiating the wt virus-infected and BoHV-1 tmv-vaccinated cattle. PMID:26976821

  11. Use of poly(lactic acid) amendments to promote the bacterial fixation of metals in zinc smelter tailings.

    PubMed

    Edenborn, H M

    2004-04-01

    The ability of poly(lactic acid) (PLA) to serve as a long-term source of lactic acid for bacterial sulfate reduction activity in zinc smelter tailings was investigated. Solid PLA polymers mixed in water hydrolyzed abiotically to release lactic acid into solution over an extended period of time. The addition of both PLA and gypsum was required for indigenous bacteria to lower redox potential, raise pH, and stimulate sulfate reduction activity in highly oxidized smelter tailings after one year of treatment. Bioavailable cadmium, copper, lead and zinc were all lowered significantly in PLA/gypsum treated soil, but PLA amendments alone increased the bioavailability of lead, nickel and zinc. Similar PLA amendments may be useful in constructed wetlands and reactive barrier walls for the passive treatment of mine drainage, where enhanced rates of bacterial sulfate reduction are desirable. PMID:14693443

  12. Multicomponent reactive transport modeling of acid neutralization reactions in mine tailings

    NASA Astrophysics Data System (ADS)

    Jurjovec, Jasna; Blowes, David W.; Ptacek, Carol J.; Mayer, K. Ulrich

    2004-11-01

    Multicomponent reactive transport modeling was conducted to analyze and quantify the acid neutralization reactions observed in a column experiment. Experimental results and the experimental procedures have been previously published. The pore water geochemistry was described by dissolution and precipitation reactions involving primary and secondary mineral phases. The initial amounts of the primary phases ankerite-dolomite, siderite, chlorite, and gypsum were constrained by mineralogical analyses of the tailings sample used in the experiment. Secondary gibbsite was incorporated into the model to adequately explain the changes in pH and concentration changes of Al in the column effluent water. The results of the reactive transport modeling show that the pH of the column effluent water can be explained by dissolution reactions of ankerite-dolomite, siderite, chlorite, and secondary gibbsite. The modeling results also show that changes in Eh can be explained by dissolution of ferrihydrite during the experiment. In addition, the modeling results show that the kinetically limited dissolution of chlorite contributes the largest mass of dissolved Mg and Fe (II) in the effluent water, followed by ankerite-dolomite, which contributes substantially less. In summary, reactive transport modeling based on detailed geochemical and mineralogical data was successful to quantitatively describe the changes in pH and major ions in the column effluent.

  13. Differential expression of peroxisome proliferator-activated receptor γ, fatty acid synthase, and hormone-sensitive lipase in fat-tailed and thin-tailed sheep breeds.

    PubMed

    Xu, X C; Li, B B; Wei, X; Yang, Y X; Wang, X L; Chen, Y L

    2015-01-01

    Tail fat content affects meat quality, and it varies in different sheep breeds. Theoretically, lipid metabolism contributes to variation in tail fat content. Tail length, tail width, and tail girth were measured in live Tong sheep (with both short fat tail and long fat tail), Shaanbei fine wool sheep (long thin tail), Tan sheep (short fat tail), Kazakh sheep (hip fat tail), and Tibetan sheep (short thin tail). The expression levels of genes related to tail adipose tissue lipid metabolism were investigated, which included lipogenetic genes (PPARγ and FAS) and lipolytic gene (HSL). Differences were observed (P < 0.05) in PPARγ mRNA expression levels in the different breeds; FAS mRNA expression levels did not differ (P > 0.05) in Tong sheep with short fat tail, Tong sheep with long fat tail, Shaanbei fine wool sheep, and Tibetan sheep; HSL mRNA expression levels were not different (P > 0.05) in Tong sheep. PPARγ and HSL protein expression levels differed (P < 0.05) between the different breeds; FAS protein expression levels were different (P < 0.05) in Tong sheep with long fat tails, Tan sheep, Kazakh sheep, and Tibetan sheep, but did not differ (P > 0.05) in Tong sheep with short fat tails and Shaanbei fine wool sheep. These results provide useful information to further understand the function of PPARγ, FAS, and HSL in sheep tail lipid metabolism, which should be applicable to studies on the regulation of fat deposition and improvement of meat quality. PMID:26634530

  14. Migration of acidic groundwater seepage from uranium-tailings impoundments, 1. Field study and conceptual hydrogeochemical model

    NASA Astrophysics Data System (ADS)

    Morin, Kevin A.; Cherry, John A.; Dave, Nand K.; Lim, Tjoe P.; Vivyurka, Al J.

    1988-08-01

    In this first paper of a series, the results of a study at a non-operational tailings site are presented and are used to construct a general conceptual model for seepage migration from uranium-tailings impoundments. Many parts of the model are applicable to other types of tailings and to acid drainage in general. At the field site, the impoundment lies over a portion of a glaciofluvial sand aquifer. Tailings seepage drains downward into the aquifer and then migrates laterally away. Results of the field study indicate the seepage can be divided into three geochemical zones: (1) the inner core, which is essentially unaltered, acidic seepage from the tailings; (2) the neutralization zone, in which inner-core water is neutralized and aqueous concentrations decrease significantly; and (3) the outer zone, which contains both neutralized water from the neutralization zone and pH-neutral process water from the uranium milling operation. Yearly comparisons from 1979 to 1984 indicate the neutralization zone and inner core are migrating downgradient at a rate of about 1 meter/year, which is about 1/440 of the groundwater velocity. The mechanisms that produce the retardation and the decreases in aqueous concentrations are part of the conceptual model. The main features of the conceptual model are solid-liquid interactions, particularly mineral precipitation-dissolution, and buffering effects of dominant aqueous species. The important minerals undergoing precipitation-dissolution are the calcite-siderite solid solution, gypsum, Al-OH minerals, and Fe-OH minerals. "Cell and streamtube" calculations are used to evaluate the general trends in aqueous concentrations and to assist in explaining observed migration rates. Co-precipitation with the above minerals apparently accounts for decreases in other major, minor, and metal solutes. Because of the large amount of mineral precipitation and co-precipitation, variations in 2H and 18O were observed over a flow distance of several

  15. Functional analysis of the cytoplasmic domain of the integrin {alpha}1 subunit in endothelial cells.

    PubMed

    Abair, Tristin D; Bulus, Nada; Borza, Corina; Sundaramoorthy, Munirathinam; Zent, Roy; Pozzi, Ambra

    2008-10-15

    Integrin alpha1beta1, the major collagen type IV receptor, is expressed by endothelial cells and plays a role in both physiologic and pathologic angiogenesis. Because the molecular mechanisms whereby this collagen IV receptor mediates endothelial cell functions are poorly understood, truncation and point mutants of the integrin alpha1 subunit cytoplasmic tail (amino acids 1137-1151) were generated and expressed into alpha1-null endothelial cells. We show that alpha1-null endothelial cells expressing the alpha1 subunit, which lacks the entire cytoplasmic tail (mutant alpha1-1136) or expresses all the amino acids up to the highly conserved GFFKR motif (mutant alpha1-1143), have a similar phenotype to parental alpha1-null cells. Pro(1144) and Leu(1145) were shown to be necessary for alpha1beta1-mediated endothelial cell proliferation; Lys(1146) for adhesion, migration, and tubulogenesis and Lys(1147) for tubulogenesis. Integrin alpha1beta1-dependent endothelial cell proliferation is primarily mediated by ERK activation, whereas migration and tubulogenesis require both p38 MAPK and PI3K/Akt activation. Thus, distinct amino acids distal to the GFFKR motif of the alpha1 integrin cytoplasmic tail mediate activation of selective downstream signaling pathways and specific endothelial cell functions. PMID:18647959

  16. In vitro acetylation of HMGB-1 and -2 proteins by CBP: the role of the acidic tail.

    PubMed

    Pasheva, Evdokia; Sarov, Mihail; Bidjekov, Kiril; Ugrinova, Iva; Sarg, Bettina; Lindner, Herbert; Pashev, Iliya G

    2004-03-16

    Histone acetyltransferases CBP, PCAF, and Tip60 have been tested for their ability to in vitro acetylate HMGB-1 and -2 proteins and their truncated forms lacking the C-terminal tail. It was found that these proteins were substrates for CBP only. Analyses of modified proteins by electrophoresis, amino acid sequencing, and mass spectrometry showed that full-length HMGB-1 and -2 were monoacetylated at Lys2. Removal of the C terminus resulted in (i) an increased incorporation of radiolabeled acetate within the proteins to a level close to that observed with histones H3/H4 and (ii) creation of a novel target site at Lys81. Acetylated and nonmodified HMGB-1 and -2 protein lacking the acidic tail were compared relative to their binding affinity to distorted DNA and the ability to bend linear DNA. Both proteins showed similar affinities to cisplatin-damaged DNA; the acetylated protein, however, was 3-fold more effective in inducing ligase-mediated circularization of a 111-bp DNA fragment. The alterations in the acetylation pattern of HMGB-1 and -2 upon removal of the C-terminal tail are regarded as a means by which the acidic domain modulates some properties of these proteins. PMID:15005629

  17. Bio-physicochemical effects of gamma irradiation treatment for naphthenic acids in oil sands fluid fine tailings.

    PubMed

    Boudens, Ryan; Reid, Thomas; VanMensel, Danielle; Prakasan M R, Sabari; Ciborowski, Jan J H; Weisener, Christopher G

    2016-01-01

    Naphthenic acids (NAs) are persistent compounds that are components of most petroleum, including those found in the Athabasca oil sands. Their presence in freshly processed tailings is of significant environmental concern due to their toxicity to aquatic organisms. Gamma irradiation (GI) was used to reduce the toxicity and concentration of NAs in oil sands process water (OSPW) and fluid fine tailings (FFT). This investigation systematically studied the impact of GI on the biogeochemical development and progressive reduction of toxicity using laboratory incubations of fresh and aged tailings under anoxic and oxic conditions. GI reduced NA concentrations in OSPW by up to 97% in OSPW and in FFT by 85%. The GI-treated FFT exhibited increased rates of biogeochemical change, dependent on the age of the tailings source. Dissolved oxygen (DO) flux was enhanced in GI-treated FFT from fresh and aged source materials, whereas hydrogen sulfide (HS(-)) flux was stimulated only in the fresh FFT. Acute toxicity to Vibrio fischeri was immediately reduced following GI treatment of fresh OSPW. GI treatment followed by 4-week incubation reduced toxicity of aged OSPW to V. fischeri. PMID:26356184

  18. Estimation of free energy barriers in the cytoplasmic and mitochondrial aspartate aminotransferase reactions probed by hydrogen-exchange kinetics of C alpha-labeled amino acids with solvent

    SciTech Connect

    Julin, D.A.; Wiesinger, H.; Toney, M.D.; Kirsch, J.F. )

    1989-05-02

    The existence of the postulated quinonoid intermediate in the cytoplasmic aspartate amino-transferase catalyzed transamination of aspartate to oxaloacetate was probed by determining the extent of transfer of tritium from the C alpha position of tritiated L-aspartate to pyridoxamine 5'-phosphate in single turnover experiments in which washout from the back-reaction was obviated by product trapping. The maximum amount of transferred tritium observed was 0.7%, consistent either with a mechanism in which a fraction of the net transamination reaction proceeds through a quinonoid intermediate or with a mechanism in which this intermediate is formed off the main reaction pathway. It is shown that transfer of labeled hydrogen from the amino acid to cofactor cannot be used to differentiate a stepwise from a concerted transamination mechanism. The amount of tritium transferred is a function of the rate constant for torsional equilibration about the epsilon-amino group of Lys-258, the presumptive abstractor of the C alpha proton; the relative rate constants for hydrogen exchange with solvent versus cofactor protonation; and the tritium isotope effect on this ratio. The free energy barriers facing the covalent intermediate between aldimine and keto acid product (i.e., ketimine and possibly quinonoid) were evaluated relatively by comparing the rates of C alpha-hydrogen exchange in starting amino acid with the rates of keto acid formation. The value of theta (= kexge/kprod) was found to be 2.6 for the reaction of cytoplasmic isozyme with aspartate and ca. 0.5 for that of the mitochondrial form with glutamate.

  19. Determination of thermodynamic and transport parameters of naphthenic acids and organic process chemicals in oil sand tailings pond water.

    PubMed

    Wang, Xiaomeng; Robinson, Lisa; Wen, Qing; Kasperski, Kim L

    2013-07-01

    Oil sand tailings pond water contains naphthenic acids and process chemicals (e.g., alkyl sulphates, quaternary ammonium compounds, and alkylphenol ethoxylates). These chemicals are toxic and can seep through the foundation of the tailings pond to the subsurface, potentially affecting the quality of groundwater. As a result, it is important to measure the thermodynamic and transport parameters of these chemicals in order to study the transport behavior of contaminants through the foundation as well as underground. In this study, batch adsorption studies and column experiments were performed. It was found that the transport parameters of these chemicals are related to their molecular structures and other properties. The computer program (CXTFIT) was used to further evaluate the transport process in the column experiments. The results from this study show that the transport of naphthenic acids in a glass column is an equilibrium process while the transport of process chemicals seems to be a non-equilibrium process. At the end of this paper we present a real-world case study in which the transport of the contaminants through the foundation of an external tailings pond is calculated using the lab-measured data. The results show that long-term groundwater monitoring of contaminant transport at the oil sand mining site may be necessary to avoid chemicals from reaching any nearby receptors. PMID:23736740

  20. The Effect of Lactic Acid Bacteria-fermented Soybean Milk Products on Carrageenan-induced Tail Thrombosis in Rats

    PubMed Central

    KAMIYA, Seitaro; OGASAWARA, Masayoshi; ARAKAWA, Masayuki; HAGIMORI, Masayori

    2013-01-01

    Thrombosis is characterized by congenital and acquired procatarxis. Lactic acid bacteria-fermented soybean milk products (FS-LAB) inhibit hepatic lipid accumulation and prevent atherosclerotic plaque formation. However, the therapeutic efficacy of FS-LAB against thrombosis has yet to be investigated. In this study, FS-LAB were administered subcutaneously into the tails of rats, with the subsequent intravenous administration of κ-carrageenan 12 hr after the initial injection. In general, administration of κ-carrageenan induces thrombosis. The length of the infarcted tail regions was significantly shorter in the rats administered a single-fold or double-fold concentration of the FS-LAB solution compared with the region in control rats. Therefore, FS-LAB exhibited significant antithrombotic effects. Our study is the first to characterize the properties of FS-LAB and, by testing their efficacy on an in vivo rat model of thrombosis, demonstrate the potency of their antithrombotic effect. PMID:24936368

  1. Geochemical characterisation of seepage and drainage water quality from two sulphide mine tailings impoundments: Acid mine drainage versus neutral mine drainage

    USGS Publications Warehouse

    Heikkinen, P.M.; Raisanen, M.L.; Johnson, R.H.

    2009-01-01

    Seepage water and drainage water geochemistry (pH, EC, O2, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.

  2. Dopamine D2 receptor activates extracellular signal-regulated kinase through the specific region in the third cytoplasmic loop.

    PubMed

    Takeuchi, Yusuke; Fukunaga, Kohji

    2004-06-01

    To investigate whether the third cytoplasmic loop and the C-terminal cytoplasmic tail of dopamine D(2) receptor (D2R) are involved in extracellular signal-regulated kinase (ERK) activation and subsequent regulation of transcription factors, we established NG108-15 cells stably expressing D2LR and D2SR deleted 40 amino acid residues in the third cytoplasmic loop (NGD2LR-3rd-dele and NGD2SR-3rd-dele) or the C-terminal cytoplasmic tail (NGD2LR-C-dele and NGD2SR-C-dele) and evaluated these receptors' functions using luciferase reporter gene assay. Immunocytochemical studies showed similar intracellular distributions of D2LR-3rd-dele and D2SR-3rd-dele to D2LR and D2SR, respectively. Quinpirole-induced inhibition of forskolin-induced cyclic AMP responsive element (CRE) activation was not affected by the deletion of 40 amino acid residues. However, nuclear factor-kappa B (NF-kappaB) activation by D2R-3rd-dele was largely attenuated compared to that by D2R. Similarly, ERK or serum-responsive element (SRE) activation by quinpirole treatment was totally abolished in NGD2R-3rd-dele cells. Moreover, D2R-C-dele was diffusely distributed or clustered in the cell bodies and lost the receptor functions. Taken together, the 40 amino acid residues in the third cytoplasmic loop are essential for the ERK activation but not for inhibition of adenylyl cyclase through Gi/o proteins. In addition, the C-terminal cytoplasmic tail is essential for membrane association of D2Rs to elicit the receptor functions. PMID:15189353

  3. Inhibition of acid mine drainage and immobilization of heavy metals from copper flotation tailings using a marble cutting waste

    NASA Astrophysics Data System (ADS)

    Tozsin, Gulsen

    2016-01-01

    Acid mine drainage (AMD) with high concentrations of sulfates and metals is generated by the oxidation of sulfide bearing wastes. CaCO3-rich marble cutting waste is a residual material produced by the cutting and polishing of marble stone. In this study, the feasibility of using the marble cutting waste as an acid-neutralizing agent to inhibit AMD and immobilize heavy metals from copper flotation tailings (sulfide- bearing wastes) was investigated. Continuous-stirring shake-flask tests were conducted for 40 d, and the pH value, sulfate content, and dissolved metal content of the leachate were analyzed every 10 d to determine the effectiveness of the marble cutting waste as an acid neutralizer. For comparison, CaCO3 was also used as a neutralizing agent. The average pH value of the leachate was 2.1 at the beginning of the experiment ( t = 0). In the experiment employing the marble cutting waste, the pH value of the leachate changed from 6.5 to 7.8, and the sulfate and iron concentrations decreased from 4558 to 838 mg/L and from 536 to 0.01 mg/L, respectively, after 40 d. The marble cutting waste also removed more than 80wt% of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) from AMD generated by copper flotation tailings.

  4. Effect of endurance training and/or fish oil supplemented diet on cytoplasmic fatty acid binding protein in rat skeletal muscles and heart.

    PubMed

    Clavel, Stéphan; Farout, L; Briand, M; Briand, Y; Jouanel, P

    2002-07-01

    Endurance training and/or a fish oil supplemented diet affect cytoplasmic fatty acid binding protein (FABP(c)) content in rat skeletal muscles and heart. After 8 weeks of swimming, trained rats exhibited higher FABP(c) content in the extensor digitorum longus (EDL) and in the gastrocnemius than did control rats (30%). The FABP(c) increase was associated with an increase of citrate synthase activity (85% and 93%, respectively, in the two muscles), whereas lactate dehydrogenase activity decreased significantly. In contrast, in the soleus and in the heart we did not observe any effect of exercise either on FABP(c) or on the metabolic profile. Therefore, increasing oxidative capacities of muscle by exercise resulted in a concomitant increase of the FABP(c) content. Giving a polyunsaturated fatty acid (omega-3) supplemented diet for eight weeks induced a large rise of the FABP(c) in EDL (300%), gastrocnemius (250%), soleus (50%) and heart (15%) without a concurrent accumulation of intramuscular triglycerides or modification of the citrate synthase activity, suggesting that polyunsaturated fatty acids may increase FABP(c) content by up-regulating fatty acid metabolism genes via peroxisome proliferator-activated receptor alpha activation. Endurance trained rats fed with an omega-3 diet had similar FABP(c) content in the gastrocnemius muscle when compared to sedentary omega-3 fed rats, whereas an additive effect of exercise and diet was observed in the EDL. The FABP(c) in the soleus and in the heart of rats fed with omega-3 supplements remained constant whether rats performed exercise or not. As a result, both exercise and omega-3-enriched diet influenced FABP(c) content in muscle. These two physiological treatments presumably acted on FABP(c) content by increasing fatty acid flux within the cell. PMID:12111278

  5. Contact of clay-liner materials with acidic tailings. II. Chemical modeling

    SciTech Connect

    Peterson, S.R.; Krupka, K.M.

    1981-09-01

    The ion speciation-solubility model WATEQ3 was used to model original aqueous solutions and solutions resulting from liner materials contacted with uranium mill tailings, synthetic mill tailings or H/sub 2/SO/sub 4/. The modeling results indicate solution species which are in apparent equilibrium with respect to particular solids. These solids provide potential solubility controls for their corresponding dissolved constituents. The disequilibrium indices computed by WATEQ3 indicate amorphic Fe(OH)/sub 3/(A), Al0HO/sub 4/, alunite (KA1/sub 3/(SO/sub 4/)/sub 2/(OH)/sub 6/), gypsum (CaSO/sub 4/ . 2H/sub 2/O), celestite (SrSO/sub 4/), anglesite (PbSO/sub 4/) and MnHPO/sub 4/ may have precipitated in the contacted liner materials and may also provide solubility controls for their dissolved constituents. The disequilibrium indices also show that the solutions resulting from the interaction of Highland Mill tailings are oversaturated with K-, H-, and Na-jarosites ((K,H,Na)Fe/sub 3/(SO/sub 4/)/sub 2/(OH)/sub 6/). Because jarosite has been identified by x-ray diffraction as a precipitate in these reacted liner materials, it would appear that there is a kinetic barrier which prohibits jarosite from being an effective solubility control. Results of this study also show that the solubilities of many solid phases were pH dependent. This exploratory use of geochemical modeling has demonstrated its capability to test solubility hypotheses for clay liners reacted with tailings solutions and to guide the analyses of important constituents and parameters for these solutions. Geochemical modeling can be used, in parallel with characterization techniques for the solid phases, to support the presence of the solid phase and to guide the search for further solid phases. Geochemical modeling is also an effective tool in delineating the chemical causes for changes in permeability of liner materials.

  6. Crystallogenesis of bacteriophage P22 tail accessory factor gp26 at acidic and neutral pH

    SciTech Connect

    Cingolani, Gino Andrews, Dewan; Casjens, Sherwood

    2006-05-01

    The crystallogenesis of bacteriophage P22 tail-fiber gp26 is described. To study possible pH-induced conformational changes in gp26 structure, native trimeric gp26 has been crystallized at acidic pH (4.6) and a chimera of gp26 fused to maltose-binding protein (MBP-gp26) has been crystallized at neutral and alkaline pH (7-10). Gp26 is one of three phage P22-encoded tail accessory factors essential for stabilization of viral DNA within the mature capsid. In solution, gp26 exists as an extended triple-stranded coiled-coil protein which shares profound structural similarities with class I viral membrane-fusion protein. In the cryo-EM reconstruction of P22 tail extracted from mature virions, gp26 forms an ∼220 Å extended needle structure emanating from the neck of the tail, which is likely to be brought into contact with the cell’s outer membrane when the viral DNA-injection process is initiated. To shed light on the potential role of gp26 in cell-wall penetration and DNA injection, gp26 has been crystallized at acidic, neutral and alkaline pH. Crystals of native gp26 grown at pH 4.6 diffract X-rays to 2.0 Å resolution and belong to space group P2{sub 1}, with a dimer of trimeric gp26 molecules in the asymmetric unit. To study potential pH-induced conformational changes in the gp26 structure, a chimera of gp26 fused to maltose-binding protein (MBP-gp26) was generated. Hexagonal crystals of MBP-gp26 were obtained at neutral and alkaline pH using the high-throughput crystallization robot at the Hauptman–Woodward Medical Research Institute, Buffalo, NY, USA. These crystals diffract X-rays to beyond 2.0 Å resolution. Structural analysis of gp26 crystallized at acidic, neutral and alkaline pH is in progress.

  7. Arabidopsis abi1-1 and abi2-1 phosphatase mutations reduce abscisic acid-induced cytoplasmic calcium rises in guard cells.

    PubMed

    Allen, G J; Kuchitsu, K; Chu, S P; Murata, Y; Schroeder, J I

    1999-09-01

    Elevations in cytoplasmic calcium ([Ca(2)+](cyt)) are an important component of early abscisic acid (ABA) signal transduction. To determine whether defined mutations in ABA signal transduction affect [Ca(2)+](cyt) signaling, the Ca(2)+-sensitive fluorescent dye fura 2 was loaded into the cytoplasm of Arabidopsis guard cells. Oscillations in [Ca(2)+](cyt) could be induced when the external calcium concentration was increased, showing viable Ca(2)+ homeostasis in these dye-loaded cells. ABA-induced [Ca(2)+](cyt) elevations in wild-type stomata were either transient or sustained, with a mean increase of approximately 300 nM. Interestingly, ABA-induced [Ca(2)+](cyt) increases were significantly reduced but not abolished in guard cells of the ABA-insensitive protein phosphatase mutants abi1 and abi2. Plasma membrane slow anion currents were activated in wild-type, abi1, and abi2 guard cell protoplasts by increasing [Ca(2)+](cyt), demonstrating that the impairment in ABA activation of anion currents in the abi1 and abi2 mutants was bypassed by increasing [Ca(2)+](cyt). Furthermore, increases in external calcium alone (which elevate [Ca(2)+](cyt)) resulted in stomatal closing to the same extent in the abi1 and abi2 mutants as in the wild type. Conversely, stomatal opening assays indicated different interactions of abi1 and abi2, with Ca(2)+-dependent signal transduction pathways controlling stomatal closing versus stomatal opening. Together, [Ca(2)+](cyt) recordings, anion current activation, and stomatal closing assays demonstrate that the abi1 and abi2 mutations impair early ABA signaling events in guard cells upstream or close to ABA-induced [Ca(2)+](cyt) elevations. These results further demonstrate that the mutations can be bypassed during anion channel activation and stomatal closing by experimental elevation of [Ca(2)+](cyt). PMID:10488243

  8. Phytotoxicity and naphthenic acid dissipation from oil sands fine tailings treatments planted with the emergent macrophyte Phragmites australis.

    PubMed

    Armstrong, Sarah A; Headley, John V; Peru, Kerry M; Mikula, Randy J; Germida, James J

    2010-01-01

    During reclamation the water associated with the runoff or groundwater flushing from dry stackable tailings technologies may become available to the reclaimed environment within an oil sands lease. Here we evaluate the performance of the emergent macrophyte, common reed (Phragmites australis), grown in chemically amended mature fine tailings (MFT) and simulated runoff/seepage water from different MFT drying treatments. The present study also investigated the phytotoxicity of the concentration of oil sands naphthenic acids (NAs) in different MFT drying chemical treatments, in both planted and unplanted systems. We demonstrate that although growth was reduced, the emergent macrophyte common reed was capable of growing in diluted unamended MFT runoff, as well as in diluted runoff from MFT amended with either 0.25% lime and gypsum or 0.5% gypsum. Common reed can thus assist in the dewatering process of oil sands MFT. However, simulated runoff or seepage waters from chemically amended and dried MFT were phytotoxic, due to combined levels of salts, naphthenic acids and pH. Phytoremediation of runoff water/ground water seepage from dry-land applied MFT will thus require pre-treatment in order to make conditions more favorable for plant growth. PMID:20486009

  9. In situ biodegradation of naphthenic acids in oil sands tailings pond water using indigenous algae-bacteria consortium.

    PubMed

    Mahdavi, Hamed; Prasad, Vinay; Liu, Yang; Ulrich, Ania C

    2015-01-01

    In this study, the biodegradation of total acid-extractable organics (TAOs), commonly called naphthenic acids (NAs), was investigated. An indigenous microbial culture containing algae and bacteria was taken from the surface of a tailings pond and incubated over the course of 120days. The influence of light, oxygen and the presence of indigenous algae and bacteria, and a diatom (Navicula pelliculosa) on the TAO removal rate were elucidated. The highest biodegradation rate was observed with bacteria growth only (without light exposure) with a half-life (t(1/2)) of 203days. The algae-bacteria consortium enhanced the detoxification process, however, bacterial biomass played the main role in toxicity reduction. Principal component analysis (PCA) conducted on FT-IR spectra, identified functional groups and bonds (representing potential markers for biotransformation of TAOs) as follows: hydroxyl, carboxyl and amide groups along with CH, arylH, arylOH and NH bonds. PMID:25841188

  10. Improvement on the thermal stability and activity of plant cytosolic ascorbate peroxidase 1 by tailing hyper-acidic fusion partners.

    PubMed

    Zhang, Mengru; Gong, Ming; Yang, Yumei; Li, Xujuan; Wang, Haibo; Zou, Zhurong

    2015-04-01

    Cytosolic ascorbate peroxidase 1 (APX1) plays a crucial role in regulating the level of plant cellular reactive oxygen species and its thermolability is proposed to cause plant heat-susceptibility. Herein, several hyper-acidic fusion partners, such as the C-terminal peptide tails, were evaluated for their effects on the thermal stability and activity of APX1 from Jatropha curcas and Arabidopsis. The hyper-acidic fusion partners efficiently improved the thermostability and prevented thermal inactivation of APX1 in both plant species with an elevated heat tolerance of at least 2 °C. These hyper-acidified thermostable APX1 fusion variants are of considerable biotechnological potential and can provide a new route to enhance the heat tolerance of plant species especially of inherent thermo-sensitivity. PMID:25515798

  11. [THE PHYSICAL CHEMICAL, BIOLOGICAL BASICS OF CELLS ABSORPTION OF UNESTERIFIED FATTY ACIDS; ALBUMIN, CAVEOLIN, CLATHRIN AND LIPID-BINDING PROTEINS OF CYTOPLASM (THE LECTURE)].

    PubMed

    Titov, V N; Shoibonov, B B

    2016-03-01

    From aposition of phylogenetic theory of general pathology, obesity and metabolic syndrome are pathology of fatty cells. However, the first is a pathology of phylogenetically early visceral fatty cells of omentum. They supply with substratum of energy realization of biologic function of trophology, homeostasis, endoecology and adaptation. The visceral fatty cells of omentum have no receptors to insulin and synthesize adaptively insulin and they are not characterized by biologic reaction of proliferation. The obesity is a pathology of late in phylogenesis subcutaneous adpocytes. They are insulin-dependent and supply with substratum of energy realization of one biologic function of locomotion--movement at the expense of constriction of cross-striated miocytes. The adipocytes in terms of adaptation synthesize humoral mediator adponectin and actively implement biologic function of proliferation. Under both aphysiologic conditions increases passive by gradient of concentration, absorption by cells albumin-unbound free fatty acids in unionized form in micellae's composition. The passive aphysiologic absorption of free fatty acids by cells which under intracellular compartmentalization don't oxidize mitochondria results in synthesis, accumulation of triglycerides in cytoplasm of cells which don't implement it physiologically. The aphysiologic absorption of free fatty acids by cells, their etherification in triglyceride, in particular, in phylogenetically late β-cells of islets and either late cardiomyocytes which fatty acids don't synthesize de novo results in development of aphysiologic processes and disorder of function. From position of biology, these cells in vivo are subjected to loss similar to apoptosis. The formation of corpuscles of apoptosis compromise biologic function of endoecology activating biologic reaction of inflammation. PMID:27506107

  12. Phospholipase C-η2 interacts with nuclear and cytoplasmic LIMK-1 during retinoic acid-stimulated neurite growth.

    PubMed

    Arastoo, Mohammed; Hacker, Christian; Popovics, Petra; Lucocq, John M; Stewart, Alan J

    2016-02-01

    Neurite growth is central to the formation and differentiation of functional neurons, and recently, an essential role for phospholipase C-η2 (PLCη2) in neuritogenesis was revealed. Here we investigate the function of PLCη2 in neuritogenesis using Neuro2A cells, which upon stimulation with retinoic acid differentiate and form neurites. We first investigated the role of the PLCη2 calcium-binding EF-hand domain, a domain that is known to be required for PLCη2 activation. To do this, we quantified neurite outgrowth in Neuro2A cells, stably overexpressing wild-type PLCη2 and D256A (EF-hand) and H460Q (active site) PLCη2 mutants. Retinoic acid-induced neuritogenesis was highly dependent on PLCη2 activity, with the H460Q mutant exhibiting a strong dominant-negative effect. Expression of the D256A mutant had little effect on neurite growth relative to the control, suggesting that calcium-directed activation of PLCη2 is not essential to this process. We next investigated which cellular compartments contain endogenous PLCη2 by comparing immunoelectron microscopy signals over control and knockdown cell lines. When signals were analyzed to reveal specific labeling for PLCη2, it was found to be localized predominantly over the nucleus and cytosol. Furthermore in these compartments (and also in growing neurites), a proximity ligand assay revealed that PLCη2 specifically interacts with LIMK-1 in Neuro2A cells. Taken together, these data emphasize the importance of the PLCη2 EF-hand domain and articulation of PLCη2 with LIMK-1 in regulating neuritogenesis. PMID:26671787

  13. Cytoplasmic bacteriophage display system

    DOEpatents

    Studier, F.W.; Rosenberg, A.H.

    1998-06-16

    Disclosed are display vectors comprising DNA encoding a portion of a structural protein from a cytoplasmic bacteriophage, joined covalently to a protein or peptide of interest. Exemplified are display vectors wherein the structural protein is the T7 bacteriophage capsid protein. More specifically, in the exemplified display vectors the C-terminal amino acid residue of the portion of the capsid protein is joined to the N-terminal residue of the protein or peptide of interest. The portion of the T7 capsid protein exemplified comprises an N-terminal portion corresponding to form 10B of the T7 capsid protein. The display vectors are useful for high copy number display or lower copy number display (with larger fusion). Compositions of the type described herein are useful in connection with methods for producing a virus displaying a protein or peptide of interest. 1 fig.

  14. Cytoplasmic bacteriophage display system

    DOEpatents

    Studier, F. William; Rosenberg, Alan H.

    1998-06-16

    Disclosed are display vectors comprising DNA encoding a portion of a structural protein from a cytoplasmic bacteriophage, joined covalently to a protein or peptide of interest. Exemplified are display vectors wherein the structural protein is the T7 bacteriophage capsid protein. More specifically, in the exemplified display vectors the C-terminal amino acid residue of the portion of the capsid protein is joined to the N-terminal residue of the protein or peptide of interest. The portion of the T7 capsid protein exemplified comprises an N-terminal portion corresponding to form 10B of the T7 capsid protein. The display vectors are useful for high copy number display or lower copy number display (with larger fusion). Compositions of the type described herein are useful in connection with methods for producing a virus displaying a protein or peptide of interest.

  15. Enumeration of Thiobacilli within pH-Neutral and Acidic Mine Tailings and Their Role in the Development of Secondary Mineral Soil

    PubMed Central

    Southam, G.; Beveridge, T. J.

    1992-01-01

    The Lemoine tailings of Chibougamau, Quebec, Canada, were deposited as a pH-neutral mineral conglomerate consisting of aluminum-silicates, iron-aluminum-silicates, pyrite, chalcopyrite, and sphalerite. These tailings are colonized by an active population of Thiobacillus ferrooxidans which is localized to an acid zone occupying 40% of the tailings' surface. This population peaked at 7 × 108 most probable number per gram of tailings during July and August 1990 and extended to a depth of 40 cm from the surface. Examination of samples over this depth profile by transmission electron microscopy and electron dispersive spectroscopy revealed a microbially mediated mineral transition from sulfides (below 40 cm) to chlorides and phosphates (at the surface). Silicate minerals were unaltered by microbial action. Transmission electron microscopy showed a tight association between Thiobacillus species and the sulfide minerals, which helps account for their prominence in tailings environments. Accurate enumeration of T. ferrooxidans from tailings required the disruption of their bonding to the mineral interface. Vortexing of a 10% aqueous suspension of the tailings material prior to most-probable-number analysis best facilitated this release. Even though heavy metals were highly mobile under acidic conditions at the Lemoine tailings, it was evident by transmission electron microscopy and electron dispersive spectroscopy that they were being immobilized as bona fide fine-grain minerals containing iron, copper, chlorine, phosphorus, and oxygen on bacterial surfaces and exopolymers. This biomineralization increased with increasing bacterial numbers and was most evident in the upper 3 cm of the acidic zone. Images PMID:16348721

  16. Pancreatic cancer-specific cell death induced in vivo by cytoplasmic-delivered polyinosine-polycytidylic acid

    PubMed Central

    Bhoopathi, Praveen; Quinn, Bridget A.; Gui, Qin; Shen, Xue-Ning; Grossman, Steven R.; Das, Swadesh K.; Sarkar, Devanand; Fisher, Paul B.; Emdad, Luni

    2014-01-01

    Polyinosine-polycytidylic acid (pIC) is a synthetic dsRNA that acts as an immune agonist of TLR3 and RLR to activate dendritic and NK cells that can kill tumor cells. pIC can also trigger apoptosis in pancreatic ductal adenocarcinoma cells but its mechanism of action is obscure. In this study, we investigated the potential therapeutic activity of a formulation of pIC with polyethylenimine ([pIC]PEI) in PDAC and investigated its mechanism of action. [pIC]PEI stimulated apoptosis in PDAC cells without affecting normal pancreatic epithelial cells. Mechanistically, [pIC]PEI repressed XIAP and survivin expression and activated an immune response by inducing MDA-5, RIG-I and NOXA. Phosphorylation of AKT was inhibited by [pIC]PEI in PDAC and this event was critical for stimulating apoptosis through XIAP and survivin degradation. In vivo administration of [pIC]PEI inhibited tumor growth via AKT-mediated XIAP degradation in both subcutaneous and quasi-orthotopic-models of PDAC. Taken together, these results offer a preclinical proof-of-concept for the evaluation of [pIC]PEI as an immunochemotherapy to treat pancreatic cancer. PMID:25205107

  17. A model for the coordinated stepping of cytoplasmic dynein.

    PubMed

    Zhao, X Y; Sun, W; Zhang, J P; Tala; Guo, W S

    2014-10-31

    Cytoplasmic dynein play an important role in transporting various intracellular cargos by coupling their ATP hydrolysis cycle with their conformational changes. Recent experimental results showed that the cytoplasmic dynein had a highly variable stepping pattern including "hand-over-hand", "inchworm" and "nonalternating-inchworm". Here, we developed a model to describe the coordinated stepping patterns of cytoplasmic dynein, based on its working cycle, construction and the interaction between its leading head and tailing head. The kinetic model showed how change in the distance between the two heads influences the rate of cytoplasmic dynein under different stepping patterns. Numerical simulations of the distribution of step size and striding rate are in good quantitative agreement with experimental observations. Hence, our coordinated stepping model for cytoplasmic dynein successfully explained its diverse stepping patterns as a molecular motor. The cooperative mechanism carried out by the two heads of cytoplasmic dynein shed light on the strategies adopted by the cytoplasmic dynein in executing various functions. PMID:25301561

  18. Structural Insights into the Mechanism of Negative Regulation of Single-box High Mobility Group Proteins by the Acidic Tail Domain*

    PubMed Central

    Stott, Katherine; Watson, Matthew; Bostock, Mark J.; Mortensen, Simon A.; Travers, Andrew; Grasser, Klaus D.; Thomas, Jean O.

    2014-01-01

    The Drosophila and plant (maize) functional counterparts of the abundant vertebrate chromosomal protein HMGB1 (HMG-D and ZmHMGB1, respectively) differ from HMGB1 in having a single HMG box, as well as basic and acidic flanking regions that vary greatly in length and charge. We show that despite these variations, HMG-D and ZmHMGB1 exist in dynamic assemblies in which the basic HMG boxes and linkers associate with their intrinsically disordered, predominantly acidic, tails in a manner analogous to that observed previously for HMGB1. The DNA-binding surfaces of the boxes and linkers are occluded in “auto-inhibited” forms of the protein, which are in equilibrium with transient, more open structures that are “binding-competent.” This strongly suggests that the mechanism of auto-inhibition may be a general one. HMG-D and ZmHMGB1 differ from HMGB1 in having phosphorylation sites in their tail and linker regions. In both cases, in vitro phosphorylation of serine residues within the acidic tail stabilizes the assembled form, suggesting another level of regulation for interaction with DNA, chromatin, and other proteins that is not possible for the uniformly acidic (hence unphosphorylatable) tail of HMGB1. PMID:25190813

  19. Trace element uptake by Eleocharis equisetina (spike rush) in an abandoned acid mine tailings pond, northeastern Australia: implications for land and water reclamation in tropical regions.

    PubMed

    Lottermoser, Bernd G; Ashley, Paul M

    2011-10-01

    This study was conducted to determine the uptake of trace elements by the emergent wetland plant species Eleocharis equisetina at the historic Jumna tin processing plant, tropical Australia. The perennial emergent sedge was found growing in acid waters (pH 2.45) and metal-rich tailings (SnAsCuPbZn). E. equisetina displayed a pronounced acid tolerance and tendency to exclude environmentally significant elements (Al, As, Cd, Ce, Co, Cu, Fe, La, Ni, Pb, Se, Th, U, Y, Zn) from its above-substrate biomass. This study demonstrates that geobotanical and biogeochemical examinations of wetland plants at abandoned mined lands of tropical areas can reveal pioneering, metal-excluding macrophytes. Such aquatic macrophytes are of potential use in the remediation of acid mine waters and sulfidic tailings and the reclamation of disturbed acid sulfate soils in subtropical and tropical regions. PMID:21550704

  20. Importance of the short cytoplasmic domain of the feline immunodeficiency virus transmembrane glycoprotein for fusion activity and envelope glycoprotein incorporation into virions

    SciTech Connect

    Celma, Cristina C.P.; Paladino, Monica G.; Gonzalez, Silvia A.; Affranchino, Jose L.

    2007-09-30

    The mature form of the envelope (Env) glycoprotein of lentiviruses is a heterodimer composed of the surface (SU) and transmembrane (TM) subunits. Feline immunodeficiency virus (FIV) possesses a TM glycoprotein with a cytoplasmic tail of approximately 53 amino acids which is unusually short compared with that of the other lentiviral glycoproteins (more than 100 residues). To investigate the relevance of the FIV TM cytoplasmic domain to Env-mediated viral functions, we characterized the biological properties of a series of Env glycoproteins progressively shortened from the carboxyl terminus. All the mutant Env proteins were efficiently expressed in feline cells and processed into the SU and TM subunits. Deletion of 5 or 11 amino acids from the TM C-terminus did not significantly affect Env surface expression, fusogenic activity or Env incorporation into virions, whereas removal of 17 or 23 residues impaired Env-mediated cell-to-cell fusion. Further truncation of the FIV TM by 29 residues resulted in an Env glycoprotein that was poorly expressed at the cell surface, exhibited only 20% of the wild-type Env fusogenic capacity and was inefficiently incorporated into virions. Remarkably, deletion of the TM C-terminal 35 or 41 amino acids restored or even enhanced Env biological functions. Indeed, these mutant Env glycoproteins bearing cytoplasmic domains of 18 or 12 amino acids were found to be significantly more fusogenic than the wild-type Env and were efficiently incorporated into virions. Interestingly, truncation of the TM cytoplasmic domain to only 6 amino acids did not affect Env incorporation into virions but abrogated Env fusogenicity. Finally, removal of the entire TM cytoplasmic tail or deletion of as many as 6 amino acids into the membrane-spanning domain led to a complete loss of Env functions. Our results demonstrate that despite its relatively short length, the FIV TM cytoplasmic domain plays an important role in modulating Env-mediated viral functions.

  1. Two independent targeting signals in the cytoplasmic domain determine trans-Golgi network localization and endosomal trafficking of the proprotein convertase furin.

    PubMed Central

    Schäfer, W; Stroh, A; Berghöfer, S; Seiler, J; Vey, M; Kruse, M L; Kern, H F; Klenk, H D; Garten, W

    1995-01-01

    Furin, a subtilisin-like eukaryotic endoprotease, is responsible for proteolytic cleavage of cellular and viral proteins transported via the constitutive secretory pathway. Cleavage occurs at the C-terminus of basic amino acid sequences, such as R-X-K/R-R and R-X-X-R. Furin was found predominantly in the trans-Golgi network (TGN), but also in clathrin-coated vesicles dispatched from the TGN, on the plasma membrane as an integral membrane protein and in the medium as an anchorless enzyme. When furin was vectorially expressed in normal rat kidney (NRK) cells it accumulated in the TGN similarly to the endogenous glycoprotein TGN38, often used as a TGN marker protein. The signals determining TGN targeting of furin were investigated by mutational analysis of the cytoplasmic tail of furin and by using the hemagglutinin (HA) of fowl plague virus, a protein with cell surface destination, as a reporter molecule, in which membrane anchor and cytoplasmic tail were replaced by the respective domains of furin. The membrane-spanning domain of furin grafted to HA does not localize the chimeric molecule to the TGN, whereas the cytoplasmic domain does. Results obtained on furin mutants with substitutions and deletions of amino acids in the cytoplasmic tail indicate that wild-type furin is concentrated in the TGN by a mechanism involving two independent targeting signals, which consist of the acidic peptide CPSDSEEDEG783 and the tetrapeptide YKGL765. The acidic signal in the cytoplasmic domain of a HA-furin chimera is necessary and sufficient to localize the reporter molecule to the TGN, whereas YKGL is a determinant for targeting to the endosomes. The data support the concept that the acidic signal, which is the dominant one, retains furin in the TGN, whereas the YKGL motif acts as a retrieval signal for furin that has escaped to the cell surface. Images PMID:7781597

  2. Polymerizable vesicles based on a single-tailed fatty acid surfactant: a simple route to robust nanocontainers.

    PubMed

    Lee, Jae-Ho; Danino, Dganit; Raghavan, Srinivasa R

    2009-02-01

    Vesicles with polymerizable bilayers have attracted interest because of their increased robustness, which is advantageous for applications. However, to prepare such vesicles, lipids with polymerizable moieties usually need to be synthesized, and this often involves cumbersome, multistep reactions. Here, we present an alternative, simpler approach based on a commercially available, single-tailed surfactant, viz. 10-undecenoic acid (UDA), a fatty acid with a terminal double bond. Previously, the polymerization of UDA micelles in water has been studied. We show that UDA can also be induced to form vesicles by adjusting the pH: vesicles form at intermediate pH (6-8), whereas at higher pH (>11), the vesicles are transformed into micelles. The presence of UDA vesicles in the pH 6-8 range is confirmed using small-angle neutron scattering (SANS) and cryotransmission electron microscopy (cryo-TEM). Subsequent thermal polymerization of UDA bilayers is done using 2,2-dimethoxy-2-phenylacetophenone (DMPA) as initiator. A partial polymerization of the bilayers is achieved, and polymerized UDA vesicles resist disruption into micelles when the solution pH is increased. To make the bilayers more robust, the vesicles are copolymerized with divinylbenzene (DVB), a hydrophobic cross-linker that partitions into the bilayer. DVB-cross-linked UDA vesicles are very stable and cannot be disrupted by detergents like Triton X-100. PMID:19138066

  3. Toxicity of gentamicin in red-tailed hawks.

    PubMed

    Bird, J E; Walser, M M; Duke, G E

    1983-07-01

    Gentamicin sulfate at dosage levels of 10 and 20 mg/kg of body weight was administered twice daily IV to red-tailed hawks. Clinical signs, water consumption, and changes in blood chemical values were monitored. Tissues were examined grossly and ultrastructurally, using light and electron microscopy. Clinical signs of weakness and apnea were attributed to gentamicin-induced neuromuscular blockade in the 20-mg/kg group. Serum values of aspartate transaminase, alanine transaminase, cholesterol, inorganic phosphorus, total protein, albumin, and uric acid increased in some birds. There was a decrease in periodic acid-Schiff staining of proximal tubular brush borders. Increased numbers of cytoplasmic lysosomes, many of which contained myelin figures, in renal epithelial cells were seen at the ultrastructural level. All birds given 20 mg/kg died. Both dosage levels were considered toxic in red-tailed hawks. PMID:6881667

  4. Cytoplasmic histidine kinase (HP0244)-regulated assembly of urease with UreI, a channel for urea and its metabolites, CO2, NH3, and NH4(+), is necessary for acid survival of Helicobacter pylori.

    PubMed

    Scott, David R; Marcus, Elizabeth A; Wen, Yi; Singh, Siddarth; Feng, Jing; Sachs, George

    2010-01-01

    Helicobacter pylori colonizes the normal human stomach by maintaining both periplasmic and cytoplasmic pH close to neutral in the presence of gastric acidity. Urease activity, urea flux through the pH-gated urea channel, UreI, and periplasmic alpha-carbonic anhydrase are essential for colonization. Exposure to pH 4.5 for up to 180 min activates total bacterial urease threefold. Within 30 min at pH 4.5, the urease structural subunits, UreA and UreB, and the Ni(2+) insertion protein, UreE, are recruited to UreI at the inner membrane. Formation of this complex and urease activation depend on expression of the cytoplasmic sensor histidine kinase, HP0244. Its deletion abolishes urease activation and assembly, impairs cytoplasmic and periplasmic pH homeostasis, and depolarizes the cells, with an approximately 7-log loss of survival at pH 2.5, even in 10 mM urea. Associated with this assembly, UreI is able to transport NH(3), NH(4)(+), and CO(2), as shown by changes in cytoplasmic pH following exposure to NH(4)Cl or CO(2). To be able to colonize cells in the presence of the highly variable pH of the stomach, the organism expresses two pH-sensor histidine kinases, one, HP0165, responding to a moderate fall in periplasmic pH and the other, HP0244, responding to cytoplasmic acidification at a more acidic medium pH. Assembly of a pH-regulatory complex of active urease with UreI provides an advantage for periplasmic buffering. PMID:19854893

  5. Cytoplasmic Tyrosine Phosphatase Shp2 Coordinates Hepatic Regulation of Bile Acid and FGF15/19 Signaling to Repress Bile Acid Synthesis

    PubMed Central

    Li, Shuangwei; Hsu, Diane D.F.; Li, Bing; Luo, Xiaolin; Alderson, Nazilla; Qiao, Liping; Ma, Lina; Zhu, Helen H.; He, Zhao; Suino-Powell, Kelly; Ji, Kaihong; Li, Jiefu; Shao, Jianhua; Xu, H. Eric; Li, Tiangang; Feng, Gen-Sheng

    2015-01-01

    Summary Bile acid (BA) biosynthesis is tightly controlled by intrahepatic negative feedback signaling elicited by BA binding to farnesoid X receptor (FXR), and also by enterohepatic communication involving ileal BA reabsorption and FGF15/19 secretion. However, how these pathways are coordinated is poorly understood. We show here that non-receptor tyrosine phosphatase Shp2 is a critical player that couples and regulates the intrahepatic and enterohepatic signals for repression of BA synthesis. Ablating Shp2 in hepatocytes suppressed signal relay from FGFR4, receptor for FGF15/19, and attenuated BA activation of FXR signaling, resulting in elevation of systemic BA levels and chronic hepatobiliary disorders in mice. Acting immediately downstream of FGFR4, Shp2 associates with FRS2α and promotes the receptor activation and signal relay to several pathways. These results elucidate a molecular mechanism for the control of BA homeostasis by Shp2 through orchestration of multiple signals in hepatocytes. PMID:24981838

  6. Amino acid-based cationic lipids with α-tocopherol hydrophobic tail for efficient gene delivery.

    PubMed

    Yi, Wen-Jing; Zheng, Li-Ting; Su, Rong-Chuan; Liu, Qiang; Zhao, Zhi-Gang

    2015-11-01

    In this work, three amino acid-based cationic lipids L1-L3 bearing the same α-tocopherol moiety and biodegradable ester bond linkage, but differing in the polar head-group, were prepared and applied as non-viral gene delivery vectors. The physicochemical properties such as size, zeta-potential, stability, and cellular uptake of the lipoplexes formed from lipids L1-L3 as well as the transfection efficacy (TE) were investigated. The results showed that the chemical composition of the cationic head-group clearly affects the physicochemical parameters of the amino acid-based lipids, especially the TE. Besides their low cytotoxicity, these lipoplexes also showed comparable TE to commercially available lipofectamine 2000. In particular, dipeptide lipid L3 gave excellent TE, which was 1.8 times higher than bPEI 25k in the presence of 10% serum in Hela cells. These results demonstrate the promising use of novel dipeptide lipids for safe and efficient gene delivery. PMID:25973654

  7. RhoA activation and actin reorganization involved in endothelial CAM-mediated endocytosis of anti-PECAM carriers: critical role for tyrosine 686 in the cytoplasmic tail of PECAM-1.

    PubMed

    Garnacho, Carmen; Shuvaev, Vladimir; Thomas, Anu; McKenna, Lindsay; Sun, Jing; Koval, Michael; Albelda, Steven; Muzykantov, Vladimir; Muro, Silvia

    2008-03-15

    Platelet-endothelial cell adhesion molecule-1 (PECAM-1), a transmembrane glycoprotein involved in leukocyte transmigration, represents a good target for endothelial drug delivery (eg, using antibody-directed nanocarriers, anti-PECAM/NCs). Although endothelial cells do not internalize PECAM antibodies, PECAM-1 engagement by multivalent anti-PECAM conjugates and nanocarriers causes endocytosis via a nonclassic CAM-mediated pathway. We found that endothelial uptake of multivalent anti-PECAM complexes is associated with PECAM-1 phosphorylation. Using model REN cells expressing a series of PECAM-1 deletion and point mutants, we found that the PECAM-1 cytoplasmic domain and, more precisely, PECAM-1 tyrosine 686, is critical in mediating RhoA activation and recruitment of EGFP-RhoA to anti-PECAM/NC binding sites at the plasmalemma, actin polymerization into phalloidin-positive stress fibers, and finally CAM endocytosis of anti-PECAM/NCs. Endothelial targeting and endocytosis of anti-PECAM/NCs were markedly efficient and did not compromise endothelial barrier function in vitro (determined by immunostaining of VE-cadherin and (125)I-albumin transport across endothelial monolayers) or in vivo (determined by electron microscopy imaging of pulmonary capillaries and (125)I-albumin transport from the blood into the lung tissue after intravenous injection of anti-PECAM/NCs in mice). These results reveal PECAM-1 signaling and interactions with the cytoskeleton, which are required for CAM-endocytosis, and may provide safe intra-endothelial drug delivery by anti-PECAM/NCs. PMID:18182571

  8. Chloroplast and Cytoplasmic Enzymes

    PubMed Central

    Anderson, Louise E.; Pacold, Ivan

    1972-01-01

    Several peaks of aldolase activity are found in the isoelectric focusing pattern of pea (Pisum sativum) leaf chloroplast extracts. One peak, separated by 0.5 pH unit from the major chloroplast aldolase peak, is found when cytoplasmic extracts are focused. The chloroplast and cytoplasmic enzymes have a pH 7.4 optimum with fructose 1,6-diphosphate. The Michaelis constant for fructose-1,6-diphosphate is 19 μM for the chloroplast, 21 μM for the cytoplasmic enzyme, and for sedoheptulose 1,7-diphosphate, 8 μM for the chloroplast enzyme, 18 μM for the cytoplasmic enzyme. Both enzymes are inhibited by d-glyceraldehyde 3-phosphate and by ribulose 1,5-diphosphate. The similarity in the catalytic properties of the isoenzymes suggests that both enzymes have an amphibolic role in carbon metabolism in the green leaf. PMID:16657968

  9. Naphthenic acids degradation and toxicity mitigation in tailings wastewater systems and aquatic environments: a review.

    PubMed

    Kannel, Prakash R; Gan, Thian Y

    2012-01-01

    Naphthenic acids, NAs (classical formula C(n)H(2n+z)O(2), where n is the carbon numbers, z represents zero or negative even integers), found in oil sands process waters (OSPWs), are toxic to aquatic environments depending upon several factors such as pH, salinity, molecular size and chemical structure of NAs. Among various available methods, biodegradation seems to be generally the most cost-effective method for decreasing concentrations of NAs (n ≤ 21) and reducing their associated toxicity in OSPW, however the mechanism by which the biodegradation of NAs occurs are poorly understood. Ozonation is superior over biodegradation in decreasing higher molecular weight alkyl branched NAs (preferentially, n ≥ 22, -6 ≥ z ≥ -12) as well as enabling accelerated biodegradation and reducing toxicity. Photolysis (UV at 254 nm) is effective in cleaving higher molecular weight NAs into smaller fragments that will be easier for microorganisms to degrade, whereas photocatalysis can metabolize selective NAs (0 ≥ z ≥ -6) efficiently and minimize their associated toxicity. Phytoremediation is applicable for metabolizing specific NAs (O(2), O(3), O(4), and O(5) species) and minimizing their associated toxicities. Petroleum coke (PC) adsorption is effective in reducing the more structurally complex NAs (preferentially 12 ≥ n ≥ 18 and z = -10, -12) and their toxicity in OSPWs, depending upon the PC content, pH and temperature. Several factors have influence on the degradation of NAs in OSPWs and aquatic environments, which include molecular mass and chemical structure of NAs, sediment structure, temperature, pH, dissolved oxygen, nutrients, and bacteria types. PMID:22217078

  10. Effect of Arbuscular Mycorrhizal Fungi on Plant Biomass and the Rhizosphere Microbial Community Structure of Mesquite Grown in Acidic Lead/Zinc Mine Tailings

    PubMed Central

    Solís-Domínguez, Fernando A.; Valentín-Vargas, Alexis; Chorover, Jon; Maier, Raina M.

    2011-01-01

    Mine tailings in arid and semi-arid environments are barren of vegetation and subject to eolian dispersion and water erosion. Revegetation is a cost-effective strategy to reduce erosion processes and has wide public acceptance. A major cost of revegetation is the addition of amendments, such as compost, to allow plant establishment. In this paper we explore whether arbuscular mycorrhizal fungi (AMF) can help support plant growth in tailings at a reduced compost concentration. A greenhouse experiment was performed to determine the effects of three AMF inocula on biomass, shoot accumulation of heavy metals, and changes in the rhizosphere microbial community structure of the native plant Prosopis juliflora (mesquite). Plants were grown in an acidic lead/zinc mine tailings amended with 10% (w/w) compost amendment, which is slightly sub-optimal for plant growth in these tailings. After two months, AMF-inoculated plants showed increased dry biomass and root length (p < 0.05) and effective AMF colonization compared to controls grown in uninoculated compost-amended tailings. Mesquite shoot tissue lead and zinc concentrations did not exceed domestic animal toxicity limits regardless of whether AMF inoculation was used. The rhizosphere microbial community structure was assessed using denaturing gradient gel electrophoresis (DGGE) profiles of the small subunit RNA gene for bacteria and fungi. Canonical correspondence analysis (CCA) of DGGE profiles showed that the rhizosphere fungal community structure at the end of the experiment was significantly different from the community structure in the tailings, compost, and AMF inocula prior to planting. Further, CCA showed that AMF inoculation significantly influenced the development of both the fungal and bacterial rhizosphere community structures after two months. The changes observed in the rhizosphere microbial community structure may be either a direct effect of the AMF inocula, caused by changes in plant physiology induced by

  11. Structural basis for tubulin recognition by cytoplasmic linker protein 170 and its autoinhibition.

    PubMed

    Mishima, Masaki; Maesaki, Ryoko; Kasa, Miyuki; Watanabe, Takashi; Fukata, Masaki; Kaibuchi, Kozo; Hakoshima, Toshio

    2007-06-19

    Cytoplasmic linker protein 170 (CLIP-170) is a prototype of the plus end-tracking proteins that regulate microtubule dynamics, but it is obscure how CLIP-170 recognizes the microtubule plus end and contributes to polymerization rescue. Crystallographic, NMR, and mutation studies of two tandem cytoskeleton-associated protein glycine-rich (CAP-Gly) domains of CLIP-170, CAP-Gly-1 and CAP-Gly-2, revealed positively charged basic grooves of both CAP-Gly domains for tubulin binding, whereas the CAP-Gly-2 domain possesses a more basic groove and directly binds the EExEEY/F motif of the C-terminal acidic-tail ends of alpha-tubulin. Notably, the p150(Glued) CAP-Gly domain that is furnished with a less positively charged surface only weakly interacts with the alpha-tubulin acidic tail. Mutation studies showed that this acidic sextette motif is the minimum region for CAP-Gly binding. The C-terminal zinc knuckle domains of CLIP-170 bind the basic groove to inhibit the binding to the acidic tails. These results provide a structural basis for the proposed CLIP-170 copolymerization with tubulin on the microtubule plus end. CLIP-170 strongly binds the acidic tails of EB1 as well as those of alpha-tubulins, indicating that EB1 localized at the plus end contributes to CLIP-170 recruitment to the plus end. We suggest that CLIP-170 stimulates microtubule polymerization and/or nucleation by neutralizing the negative charges of tubulins with the highly positive charges of the CLIP-170 CAP-Gly domains. Once CLIP-170 binds microtubule, the released zinc knuckle domain may serve to recruit dynein to the plus end by interacting with p150(Glued) and LIS1. Thus, our structures provide the structural basis for the specific dynein loading on the microtubule plus end. PMID:17563362

  12. Evolution of soil properties and metals in acid and alkaline mine tailing ponds after amendments and microorganisms application

    NASA Astrophysics Data System (ADS)

    Acosta, Jose A.; Faz, Ángel; Zornoza, Raúl; Martínez-Martínez, Silvia; Bech, Jaume

    2015-04-01

    Intense mining activities in the past were carried out in Cartagena-La Unión mining district, SE Spain, and caused excessive accumulation of toxic metals in tailing ponds which poses a high environmental and ecological risk. One of the remediation options gaining considerable interest in recent years is the in situ immobilization of metals. A corresponding reduction in the plant-available metal fraction allows re-vegetation and ecosystem restoration of the heavily contaminated sites. In addition, the use of microorganisms to improve the soil condition is a new tool used to increase spontaneous plant colonization. The aim of this research was to assess the effect of amendments (pig manure, sewage sludge, and lime) and microorganisms on the evolution of soil properties and metals in acid and alkaline tailing ponds and to evaluate the content of metals in Zygophylum fabago one year after amendments application. The study was carried out in two mine ponds (acid and alkaline). Twenty seven square field plots, each one consisting of 4 m2, were located in each pond. Four different doses of microorganism (EM) (0 ml, 20 ml, 100 ml and 200 ml of microorganism solution in each plot) and one dose of pig manure (5 kg per plot), sewage sludge (4 kg per plot) and lime (22 kg per plot) were used. Organic amendment doses were calculated according to European nitrogen legislations, and lime dose was calculated according with the potential acid production through total sulphur oxidation. Three replicates of each treatment (organic amendment + lime + microorganism dose 0, 1, 2, or 3) and control soil (with no amendments) were carried out. Plots were left to the semi-arid climate conditions after the addition of amendments to simulate real potential applications of the results. Soil samples was collected every 4 month from each plot during one year, after this time Zygophylum fabago plants were sampled from each plots. Soil properties including: pH, salinity, total, inorganic and

  13. Cloning and sequence analysis of beta-4 cDNA: an integrin subunit that contains a unique 118 kd cytoplasmic domain.

    PubMed Central

    Hogervorst, F; Kuikman, I; von dem Borne, A E; Sonnenberg, A

    1990-01-01

    The alpha 6 beta 4 complex is a member of the integrin superfamily of adhesion receptors. A human keratinocyte lambda gt11 cDNA library was screened using a monoclonal antibody directed against the beta 4 subunit. Two cDNAs were selected and subsequently used to isolate a complete set of overlapping cDNA clones. The beta 4 subunit consists of 1778 amino acids with a 683 amino acid extracellular domain, a 23 amino acid transmembrane domain and an exceptionally long cytoplasmic domain of 1072 residues. The deduced amino-terminal sequence is in good agreement with the published amino-terminal sequence of purified beta 4. The extracellular domain contains five potential N-linked glycosylation sites and four cysteine-rich homologous repeat sequences. The extracellular part of the beta 4 subunit sequence shows 35% identify with other integrin beta subunits, but is the most different among this class of molecules. The transmembrane region is poorly conserved, whereas the cytoplasmic domain shows no substantial identity in any region to the cytoplasmic tails of the known beta sequences or to other protein sequences. The exceptionally long cytoplasmic domain suggests distinct interactions of the beta 4 subunit with cytoplasmic proteins. Images Fig. 2. Fig. 3. PMID:2311578

  14. Listeria Phage and Phage Tail Induction Triggered by Components of Bacterial Growth Media (Phosphate, LiCl, Nalidixic Acid, and Acriflavine)

    PubMed Central

    Duroux, Amandine; Pimpie, Romain; Duez, Jean-Marie; Milat, Marie-Louise

    2015-01-01

    The detection of Listeria monocytogenes from food is currently carried out using a double enrichment. For the ISO methodology, this double enrichment is performed using half-Fraser and Fraser broths, in which the overgrowth of L. innocua can occur in samples where both species are present. In this study, we analyzed the induction of phages and phage tails of Listeria spp. in these media and in two brain heart infusion (BHI) broths (BHIM [bioMérieux] and BHIK [Biokar]) to identify putative effectors. It appears that Na2HPO4 at concentrations ranging from 1 to 40 g/liter with an initial pH of 7.5 can induce phage or phage tail production of Listeria spp., especially with 10 g/liter of Na2HPO4 and a pH of 7.5, conditions present in half-Fraser and Fraser broths. Exposure to LiCl in BHIM (18 to 21 g/liter) can also induce phage and phage tail release, but in half-Fraser and Fraser broths, the concentration of LiCl is much lower (3 g/liter). Low phage titers were induced by acriflavine and/or nalidixic acid. We also show that the production of phages and phage tails can occur in half-Fraser and Fraser broths. This study points out that induction of phages and phage tails could be triggered by compounds present in enrichment media. This could lead to a false-negative result for the detection of L. monocytogenes in food products. PMID:25595760

  15. In situ bioremediation of naphthenic acids contaminated tailing pond waters in the athabasca oil sands region--demonstrated field studies and plausible options: a review.

    PubMed

    Quagraine, E K; Peterson, H G; Headley, J V

    2005-01-01

    Currently, there are three industrial plants that recover oil from the lower Athabasca oil sands area, and there are plans in the future for several additional mines. The extraction procedures produce large volumes of slurry wastes contaminated with naphthenic acids (NAs). Because of a "zero discharge" policy the oil sands companies do not release any extraction wastes from their leases. The process-affected waters and fluid tailings contaminated with NAs are contained on-site primarily in large settling ponds. These fluid wastes from the tailing ponds can be acutely and chronically toxic to aquatic organisms, and NAs have been associated with this toxicity. The huge tailings containment area must ultimately be reclaimed, and this is of major concern to the oil sands industry. Some reclamation options have been investigated by both pioneering industries (Syncrude Energy Inc. and Suncor Inc.) with mixed results. The bioremediation techniques have limited success to date in biodegrading NAs to levels below 19 mg/L. Some tailing pond waters have been stored for more than 10 years, and it appears that the remaining high molecular weight NAs are refractory to the natural biodegradation process in the ponds. Some plausible options to further degrade the NAs in the tailings pond water include: bioaugmentation with bacteria selected to degrade the more refractory classes of NAs; the use of attachment materials such as clays to concentrate both the NA and the NA-degrading bacteria in their surfaces and/or pores; synergistic association between algae and bacteria consortia to promote efficient aerobic degradation; and biostimulation with nutrients to promote the growth and activity of the microorganisms. PMID:15756978

  16. Micro-PIXE analysis of trace element variation in otoliths from fish collected near acid mine tailings: Potential for monitoring contaminant dispersal

    NASA Astrophysics Data System (ADS)

    Saquet, M.; Halden, N. M.; Babaluk, J.; Campbell, J. L.; Nejedly, Z.

    2002-04-01

    Otoliths from fish sampled proximal to acid mine tailings located near Sherridon, Manitoba contain elevated abundances of Zn, Mn, Fe and Cu. Sr is also present in amounts ranging from 250 to 1200 ppm with the actual levels dependent on the lake from which fish were taken. Previous work on analyzing Zn and Mn suggests Zn will typically vary between 50 and ˜100 ppm (in marine and non-marine species) and Mn between 10 and ˜100 ppm. Otoliths analyzed in this study contain up to ˜1000 ppm Zn and up to ˜400 ppm Mn; Fe is present, ranging between 50 and 100 ppm and Cu is typically 40-50 ppm. Water samples showed variation in these elements depending on proximity to the tailings.

  17. Cytoplasmic Z-RNA

    SciTech Connect

    Zarling, D.A.; Calhoun, C.J.; Hardin, C.C.; Zarling, A.H.

    1987-09-01

    Specific immunochemical probes for Z-RNA were generated and characterized to search for possible Z-RNA-like double helices in cells. Z-RNA was detected in the cytoplasm of fixed protozoan cells by immunofluorescence microscopy using these anti-Z-RNA IgCs. In contrast, autoimmune or experimentally elicited anti-DNA antibodies, specifically reactive with B-DNA or Z-DNA, stained the nuclei. Pre-or nonimmune IgGs did not bind to the cells. RNase A or T1 digestion eliminated anti-Z-RNA IgG binding to cytoplasmic determinants; however, DNase I or mung bean nuclease had no effect. Doxorubicin and ethidium bromide prevented anti-Z-RNA antibody binding; however, actinomycin D, which does not bind double-stranded RNA, did not. Anti-Z-RNA immunofluorescence was specifically blocked in competition assays by synthetic Z-RNA but not Z-DNA, A-RNA, or single-stranded RNAs. Thus, some cytoplasmic sequences in fixed cells exist in the left-handed Z-RNA conformation.

  18. Further studies on the use of allopurinol to reduce plasma uric acid concentrations in the Red-tailed Hawk (Buteo jamaicensis) hyperuricaemic model.

    PubMed

    Poffers, J; Lumeij, J T; Timmermans-Sprang, E P M; Redig, P T

    2002-12-01

    The present paper reports the effects of allopurinol in a raptor hyperuricaemic model. The study was performed as a follow-up to previous experiments wherein allopurinol was used in doses of 100 and 50 mg/kg, and was proved to be toxic at these higher dose rates. To investigate whether 25 mg/kg (semel in die) s.i.d. allopurinol is a safe and effective dose in Red-tailed Hawks (Buteo jamaicensis) to reduce plasma uric acid concentrations, experimental studies were performed using the physiologically occurring postprandial hyperuricaemia. Preprandial and postprandial plasma concentrations of xanthine, hypoxanthine, allopurinol, oxypurinol and uric acid were established by high-performance liquid chromatography at various time intervals after receiving allopurinol (25 mg/kg SID) or placebo. No significant differences were observed between the experimental and the control group. These results indicate that this dose is safe to administer; however, this dose failed to cause a significant effect on plasma uric acid concentrations. Because of the low therapeutic ratio of allopurinol in Red-tailed Hawks, follow-up studies have concentrated on an alternative for the treatment of hyperuricaemia, namely urate oxidase. PMID:12593739

  19. Tail Buffeting

    NASA Technical Reports Server (NTRS)

    Abdrashitov, G.

    1943-01-01

    An approximate theory of buffeting is here presented, based on the assumption of harmonic disturbing forces. Two cases of buffeting are considered: namely, for a tail angle of attack greater and less than the stalling angle, respectively. On the basis of the tests conducted and the results of foreign investigators, a general analysis is given of the nature of the forced vibrations the possible load limits on the tail, and the methods of elimination of buffeting.

  20. The cytoplasmic extension of the integrin β6 subunit regulates epithelial-to-mesenchymal transition.

    PubMed

    Lee, Carlin; Lee, Casey; Lee, Stacey; Siu, Amanda; Ramos, Daniel M

    2014-02-01

    Prognosis for oral cancer patients has not improved in over 60 years due to invasion and recurrence. To understand the invasive behavior of this tumor, we evaluated the role of the αvβ6 integrin. Invasive oral SCC cells express the αvβ6 integrin, which contains an 11-amino-acid extension on its β-subunit unique to the integrin family. We determined that this β6 cytoplasmic extension regulates the composition of the intermediate filament network and the organization of signaling structures called focal contacts. The auto-phosphorylation of FAK, which is localized to focal contacts, was also regulated by the β6-cytoplasmic tail, as were the transcription factors Notch and STAT3. Lastly, we also determined that activation of MAPK required the full-length β6 integrin. Together these results indicate that the signaling critical to epithelial-to-mesenchymal transition (EMT) is regulated by the β6 integrin cytoplasmic domain. PMID:24510996

  1. Growth of Quailbush in Acidic, Metalliferous Desert Mine Tailings: Effect of Azospirillum brasilense Sp6 on Biomass Production and Rhizosphere Community Structure

    PubMed Central

    de-Bashan, Luz E.; Hernandez, Juan-Pablo; Nelson, Karis N.; Bashan, Yoav

    2010-01-01

    Mine tailing deposits in semiarid and arid environments frequently remain devoid of vegetation due to the toxicity of the substrate and the absence of a diverse soil microbial community capable of supporting seed germination and plant growth. The contribution of the plant growth promoting bacterium (PGPB) Azospirillum brasilense Sp6 to the growth of quailbush in compost-amended, moderately acidic, high-metal content mine tailings using an irrigation-based reclamation strategy was examined along with its influence on the rhizosphere bacterial community. Sp6 inoculation resulted in a significant (2.2-fold) increase in plant biomass production. The data suggest that the inoculum successfully colonized the root surface and persisted throughout the 60-day experiment in both the rhizosphere, as demonstrated by excision and sequencing of the appropriate denaturing gradient gel electrophoresis (DGGE) band, and the rhizoplane, as indicated by fluorescent in situ hybridization of root surfaces. Changes in rhizosphere community structure in response to Sp6 inoculation were evaluated after 15, 30, and 60 days using DGGE analysis of 16S rRNA polymerase chain reaction amplicons. A comparison of DGGE profiles using canonical correspondence analysis revealed a significant treatment effect (Sp6-inoculated vs. uninoculated plants vs. unplanted) on bacterial community structure at 15, 30, and 60 days (p<0.05). These data indicate that in an extremely stressed environment such as acid mine tailings, an inoculated plant growth promoting bacterium not only can persist and stimulate plant growth but also can directly or indirectly influence rhizobacterial community development. PMID:20632001

  2. Mutations of charged amino acids at the cytoplasmic end of transmembrane helix 2 affect transport activity of the budding yeast multidrug resistance protein Pdr5p.

    PubMed

    Dou, Weiwang; Zhu, Jianhua; Wang, Tanjun; Wang, Wei; Li, Han; Chen, Xin; Guan, Wenjun

    2016-06-01

    Pdr5p is a major ATP-binding cassette (ABC) transporter in Saccharomyces cerevisiae. It displays a sequence and functional homology to the pathogenic Candida albicans multidrug resistance protein Cdr1p. The transmembrane helices of Pdr5p act in substrate recognition, binding, translocation and eventual removal of toxic substances out of the plasma membrane via the formation of a binding pocket. In this study, we identify two novel Pdr5 mutants (E574K and E580K), which exhibit impaired substrate efflux functions. Both mutants remained hypersensitive to all tested Pdr5p substrates without affecting their protein expression levels, localization or ATPase activities. As E574 and E580 are both located adjacent to the predicted cytoplasmic end of transmembrane helix 2, this implies that such charged residues are functionally essential for Pdr5p. Molecular docking studies suggest the possibility that oppositely charged substitution at residue E574 may disturb the interaction between the substrates and Pdr5p, resulting in impaired transport activity. Our results present new evidence, suggesting that transmembrane helix 2 plays an important role for the efflux function of Pdr5p. PMID:27189366

  3. Evaluation of sulfidic mine tailings solidified/stabilized with cement kiln dust and fly ash to control acid mine drainage

    SciTech Connect

    Nehdi, M.; Tariq, A.

    2008-11-15

    In the present research, industrial byproducts, namely, cement kiln dust (CKD) and Class C fly ash (FAC) have been used as candidate materials along with the partial addition of sulfate-resistant cement (SRC) in the Stabilization/solidification of polymetallic sulfidic mine tailings (MT). The effectiveness of S/S was assessed by comparing laboratory experimental values obtained from unconfined compressive strength, hydraulic conductivity and leaching propensity tests of S/S samples with regulatory standards for safe surface disposal of such wastes. Despite general regulatory compliance of compressive strength and hydraulic conductivity, some solidified/stabilized-cured matrices were found unable to provide the required immobilization of pollutants. Solidified/stabilized and 90-day cured mine tailings specimens made with composite binders containing (10% CKD + 10% FAC), (5% SRC + 15% FAC) and (5% SRC + 5% CKD + 10% FAC) significantly impaired the solubility of all contaminants investigated and proved successful in fixing metals within the matrix, in addition to achieving adequate unconfined compressive strength and hydraulic conductivity values, thus satisfying USEPA regulations. Laboratory investigations revealed that, for polymetallic mining waste, leachate concentrations are the most critical factor in assessing the effectiveness of S/S technology.

  4. Boric acid induces cytoplasmic stress granule formation, eIF2α phosphorylation, and ATF4 in prostate DU-145 cells.

    PubMed

    Henderson, Kimberly A; Kobylewski, Sarah E; Yamada, Kristin E; Eckhert, Curtis D

    2015-02-01

    Dietary boron intake is associated with reduced prostate and lung cancer risk and increased bone mass. Boron is absorbed and circulated as boric acid (BA) and at physiological concentrations is a reversible competitive inhibitor of cyclic ADP ribose, the endogenous agonist of the ryanodine receptor calcium (Ca(+2)) channel, and lowers endoplasmic reticulum (ER) [Ca(2+)]. Low ER [Ca(2+)] has been reported to induce ER stress and activate the eIF2α/ATF4 pathway. Here we report that treatment of DU-145 prostate cells with physiological levels of BA induces ER stress with the formation of stress granules and mild activation of eIF2α, GRP78/BiP, and ATF4. Mild activation of eIF2α and its downstream transcription factor, ATF4, enables cells to reconfigure gene expression to manage stress conditions and mild activation of ATF4 is also required for the differentiation of osteoblast cells. Our results using physiological levels of boric acid identify the eIF2α/ATF pathway as a plausible mode of action that underpins the reported health effects of dietary boron. PMID:25425213

  5. Analgesic and Anti-Inflammatory Properties of Gelsolin in Acetic Acid Induced Writhing, Tail Immersion and Carrageenan Induced Paw Edema in Mice

    PubMed Central

    Gupta, Ashok Kumar; Parasar, Devraj; Sagar, Amin; Choudhary, Vikas; Chopra, Bhupinder Singh; Garg, Renu; Ashish; Khatri, Neeraj

    2015-01-01

    Plasma gelsolin levels significantly decline in several disease conditions, since gelsolin gets scavenged when it depolymerizes and caps filamentous actin released in the circulation following tissue injury. It is well established that our body require/implement inflammatory and analgesic responses to protect against cell damage and injury to the tissue. This study was envisaged to examine analgesic and anti-inflammatory activity of exogenous gelsolin (8 mg/mouse) in mice models of pain and acute inflammation. Administration of gelsolin in acetic acid-induced writhing and tail immersion tests not only demonstrated a significant reduction in the number of acetic acid-induced writhing effects, but also exhibited an analgesic activity in tail immersion test in mice as compared to placebo treated mice. Additionally, anti-inflammatory function of gelsolin (8 mg/mouse) compared with anti-inflammatory drug diclofenac sodium (10 mg/kg)] was confirmed in the carrageenan injection induced paw edema where latter was measured by vernier caliper and fluorescent tomography imaging. Interestingly, results showed that plasma gelsolin was capable of reducing severity of inflammation in mice comparable to diclofenac sodium. Analysis of cytokines and histo-pathological examinations of tissue revealed administration of gelsolin and diclofenac sodium significantly reduced production of pro-inflammatory cytokines, TNF-α and IL-6. Additionally, carrageenan groups pretreated with diclofenac sodium or gelsolin showed a marked decrease in edema and infiltration of inflammatory cells in paw tissue. Our study provides evidence that administration of gelsolin can effectively reduce the pain and inflammation in mice model. PMID:26426535

  6. The epididymis, cytoplasmic droplets and male fertility

    PubMed Central

    Cooper, Trevor G

    2011-01-01

    The potential of spermatozoa to become motile during post-testicular maturation, and the relationship between the cytoplasmic droplet and fertilizing capacity are reviewed. Post-testicular maturation of spermatozoa involves the autonomous induction of motility, which can occur in vivo in testes with occluded excurrent ducts and in vitro in testicular explants, and artefactual changes in morphology that appear to occur in the testis in vitro. Both modifications may reflect time-dependent oxidation of disulphide bonds of head and tail proteins. Regulatory volume decrease (RVD), which counters sperm swelling at ejaculation, is discussed in relation to loss of cytoplasmic droplets and consequences for fertility. It is postulated that: (i) fertile males possess spermatozoa with sufficient osmolytes to drive RVD at ejaculation, permitting the droplet to round up and pinch off without membrane rupture; and (ii) infertile males possess spermatozoa with insufficient osmolytes so that RVD is inadequate, the droplet swells and the resulting flagellar angulation prevents droplet loss. Droplet retention at ejaculation is a harbinger of infertility caused by failure of the spermatozoon to negotiate the uterotubal junction or mucous and reach the egg. In this hypothesis, the epididymis regulates fertility indirectly by the extent of osmolyte provision to spermatozoa, which influences RVD and therefore droplet loss. Man is an exception, because ejaculated human spermatozoa retain their droplets. This may reflect their short midpiece, approximating head length, permitting a swollen droplet to extend along the entire midpiece; this not only obviates droplet migration and flagellar angulation but also hampers droplet loss. PMID:21076437

  7. Truncation mutagenesis of the non-alpha-helical carboxyterminal tail domain of vimentin reveals contributions to cellular localization but not to filament assembly.

    PubMed

    Rogers, K R; Eckelt, A; Nimmrich, V; Janssen, K P; Schliwa, M; Herrmann, H; Franke, W W

    1995-02-01

    We have investigated the effect of stepwise truncating the carboxyterminal domain ("tail") of the intermediate filament (IF) protein vimentin of the clawed toad, Xenopus laevis, on filament assembly in vitro and, using cell transfection, in vivo and also on the cellular topology of the structures formed. All truncations examined, except the minimal one missing the last 11 amino acids which made the protein more sensitive to changes of ionic strength, did not significantly alter IF assembly in vitro, as judged by electron microscopy, viscometry and determination of viscoelastic properties with a laser-operated torsion pendulum. Stable transfections of vimentin-free mammalian cells with cDNAs encoding these mutations resulted at 28 degrees C, i.e. the permissive temperature for assembly of Xenopus vimentin, in the formation of extended IF bundle arrays. At 37 degrees C, however, the mutants lacking more than the last 35 amino acids could leave the cytoplasm and accumulated in the nucleus, indicating a certain topogenic element is located in the tail and directs cytoplasmic restriction in the wild-type protein although this does not form IFs under these conditions. Transfer to the nucleus is, however, abolished if the IF-consensus motif at the end of the rod domain is removed, suggesting that this part of the molecule also contributes to nuclear location. Similar results were obtained with human vimentin: While the rod entered the nucleus, headless vimentin, unable to form IFs, remained restricted to the cytoplasm owing to its tail domain. In contrast, tailless human vimentin and tailless mouse desmin, which are fully assembly-competent in vitro, both formed extensive IF arrays in the cytoplasm but did not accumulate in the nucleus. We conclude that in class III IF proteins stepwise deletions in the tail, while not considerably altering IF assembly in vitro, can change the topogenesis of IF proteins and structures in the living cell. PMID:7774600

  8. Cystoviral polymerase complex protein P7 uses its acidic C-terminal tail to regulate the RNA-directed RNA polymerase P2.

    PubMed

    Alphonse, Sébastien; Arnold, Jamie J; Bhattacharya, Shibani; Wang, Hsin; Kloss, Brian; Cameron, Craig E; Ghose, Ranajeet

    2014-07-15

    In bacteriophages of the cystovirus family, the polymerase complex (PX) encodes a 75-kDa RNA-directed RNA polymerase (P2) that transcribes the double-stranded RNA genome. Also a constituent of the PX is the essential protein P7 that, in addition to accelerating PX assembly and facilitating genome packaging, plays a regulatory role in transcription. Deletion of P7 from the PX leads to aberrant plus-strand synthesis suggesting its influence on the transcriptase activity of P2. Here, using solution NMR techniques and the P2 and P7 proteins from cystovirus ϕ12, we demonstrate their largely electrostatic interaction in vitro. Chemical shift perturbations on P7 in the presence of P2 suggest that this interaction involves the dynamic C-terminal tail of P7, more specifically an acidic cluster therein. Patterns of chemical shift changes induced on P2 by the P7 C-terminus resemble those seen in the presence of single-stranded RNA suggesting similarities in binding. This association between P2 and P7 reduces the affinity of the former toward template RNA and results in its decreased activity both in de novo RNA synthesis and in extending a short primer. Given the presence of C-terminal acidic tracts on all cystoviral P7 proteins, the electrostatic nature of the P2/P7 interaction is likely conserved within the family and could constitute a mechanism through which P7 regulates transcription in cystoviruses. PMID:24813120

  9. Innovative Approach to Prevent Acid Drainage from Uranium Mill Tailings Based on the Application of Na-Ferrate (VI)

    SciTech Connect

    Fernandes, H.M.; Reinhart, D.; Lettie, L.; Franklin, M.R.; Fernandes, H.M.; Franklin, M.R.; Daly, L.J.

    2006-07-01

    The operation of uranium mining and milling plants gives rise to huge amounts of wastes from both mining and milling operations. When pyrite is present in these materials, the generation of acid drainage can take place and result in the contamination of underground and surface waters through the leaching of heavy metals and radionuclides. To solve this problem, many studies have been conducted to find cost-effective solutions to manage acid mine drainage; however, no adequate strategy to deal with sulfide-ric h wastes is currently available. Ferrate (VI) is a powerful oxidizing agent in aqueous media. Under acidic conditions, the redox potential of the Ferrate (VI) ion is the highest of any other oxidant used in wastewater treatment processes. The standard half cell reduction potential of ferrate (VI) has been determined as +2.20 V to + 0.72 V in acidic and basic solutions, respectively. Ferrate (VI) exhibits a multitude of advantageous properties, including higher reactivity and selectivity than traditional oxidant alternatives, as well as disinfectant, flocculating, and coagulant properties. Despite numerous beneficial properties in environmental applications, ferrate (VI) has remained commercially unavailable. Starting in 1953, different methods for producing a high purity, powdered ferrate (VI) product were developed. However, producing this dry, stabilized ferrate (VI) product required numerous process steps which led to excessive synthesis costs (over $20/lb) thereby preventing bulk industrial use. Recently a novel synthesis method for the production of a liquid ferrate (VI) based on hypochlorite oxidation of ferric ion in strongly alkaline solutions has been discovered (USPTO 6,790,428; September 14, 2004). This on-site synthesis process dramatically reduces manufacturing cost for the production of ferrate (VI) by utilizing common commodity feedstocks. This breakthrough means that for the first time ferrate (VI) can be an economical alternative to treating

  10. Response of amino acids in hindlimb muscles to recovery from hypogravity and unloading by tail-cast suspension

    NASA Technical Reports Server (NTRS)

    Tischler, M. E.; Henriksen, E. J.; Jacob, S.; Cook, P. H.

    1985-01-01

    Concentrations of glutamine, glutamate, aspartate (+ asparagine) and alanine were compared in hindlimb muscles of SL-3 and ground control rats. Alanine was lower in the soleus of flown rats but not of suspended animals, with no response in other muscles except a slight increase in the unloaded plantaris. With recovery, alanine in the soleus was elevated. Since no differences in alanine metabolism were found by isolated muscle, changes in muscle alanine are probably due to altered body use of this amino acid leading to varied plasma levels.

  11. Responses of amino acids in hindlimb muscles to recovery from hypogravity and unloading by tail-cast suspension

    NASA Technical Reports Server (NTRS)

    Tischler, M. E.; Henriksen, E. J.; Jacob, S.; Cook, P. H.

    1985-01-01

    Amino acids were assayed in muscles from rats exposed to 7 days of hypogravity and 12 h of gravity (F) or 6 days of suspension with (R) or without (H) 12 h of loading. In these groups, lower aspartate was common only to the soleus (SOL) relative to control muscles, the smallest difference being in group R. This difference in aspartate for F and H, but not for R, correlated with lower malate suggesting diminution of citric acid cycle intermediates. The R SOL value was increased over the H SOL. Therefore desite 12 h of loading, the F SOL was more comparable to the H SOL. The role of stress in preventing recovery of the F SOL was apparent from the ratios of glutamine/glutamate. Synthesis of glutamine is enhanced by glucocorticoids and is reflected by an increased ratio. In 5 of the 6 F muscles studied, this ratio was greater than in controls. In contrast, the ratio in all R muscles was similar to controls and showed recovery from the values in H muscles. Hence the post-flight treatment of F rats may have produced additional stress. Despite this stress, in some respects the SOL responses to hypogravity were similar to its responses to unloding by suspension.

  12. Degradation of carboxy-terminal-tagged cytoplasmic proteins by the Escherichia coli protease HflB (FtsH)

    PubMed Central

    Herman, Christophe; Thévenet, Danielle; Bouloc, Philippe; Walker, Graham C.; D’Ari, Richard

    1998-01-01

    Proteins with short nonpolar carboxyl termini are unstable in Escherichia coli. This proteolytic pathway is used to dispose of polypeptides synthesized from truncated mRNA molecules. Such proteins are tagged with an 11-amino-acid nonpolar destabilizing tail via a mechanism involving the 10Sa (SsrA) stable RNA and then degraded. We show here that the ATP-dependent zinc protease HflB (FtsH) is involved in the degradation of four unstable derivatives of the amino-terminal domain of the λcI repressor: three with nonpolar pentapeptide tails (cI104, cI105, cI108) and one with the SsrA tag (cI–SsrA). cI105 and cI-SsrA are also degraded by the ClpP-dependent proteases. Loss of ClpP can be compensated for by overproducing HflB. In an in vitro system, cI108 and cI–SsrA are degraded by HflB in an energy-dependent reaction, indicating that HflB itself recognizes the carboxyl terminus. These results establish a tail-specific pathway for removing abnormal cytoplasmic proteins via the HflB and Clp proteases. PMID:9573051

  13. Bio-mimetic surface engineering of plasmid-loaded nanoparticles for active intracellular trafficking by actin comet-tail motility.

    PubMed

    Ng, Chee Ping; Goodman, Thomas T; Park, In-Kyu; Pun, Suzie H

    2009-02-01

    Intracellular transport after endosomal escape presents one of the major barriers for efficient non-viral gene delivery because plasmid DNA and synthetic nanoparticulate carriers suffer from significantly restricted diffusion in the cytoplasm. We postulate that forces generated by actin polymerization, a mechanism used by several bacterial pathogens such as Listeria monocytogenes, can be harnessed to propel nanoparticles within the cytoplasm and thereby overcome diffusional limitations associated with gene transport in the cell cytoplasm. In this work, we synthesized and characterized plasmid DNA-containing nanoparticles modified with ActA protein, the single protein in L. monocytogenes responsible for activating actin polymerization and initiating actin comet-tail propulsion. The motility of the ActA-modified nanoparticles was assessed in Xenopus laevis cytoplasmic extract supplemented with fluorescently labeled actin. Nanoparticle motility was monitored using multi-color, time-lapse fluorescence microscopy for the formation of actin comet tails attached to the fluorescently labeled vehicle. We observed particle motility with velocities approximately 0.06 microm/s with anionic-charged plasmid carriers formed from either poly(lactic-co-glycolic acid) (PLGA) or 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) liposomes, but interestingly not with cationic particles assembled by encapsulation of plasmid with either polyethylenimine (PEI) or 1,2-dioleoyl-3-trimethylammonium-propane/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOTAP/DOPE) lipids. Control particles coated with albumin instead of ActA also showed no motility. Taken together, we have demonstrated the feasibility of translating the comet-tail propulsion mechanism to synthetic drug carriers as a potential approach to overcome intracellular transport barriers, and also have identified appropriate gene delivery systems that can be employed for this mechanism. PMID:19046764

  14. Computational insight into the catalytic implication of head/tail-first orientation of arachidonic acid in human 5-lipoxygenase: consequences for the positional specificity of oxygenation.

    PubMed

    Saura, Patricia; Maréchal, Jean-Didier; Masgrau, Laura; Lluch, José M; González-Lafont, Àngels

    2016-08-17

    In the present work we have combined homology modeling, protein-ligand dockings, quantum mechanics/molecular mechanics calculations and molecular dynamics simulations to generate human 5-lipoxygenase (5-LOX):arachidonic acid (AA) complexes consistent with the 5-lipoxygenating activity (which implies hydrogen abstraction at the C7 position). Our results suggest that both the holo and the apo forms of human Stable 5-LOX could accommodate AA in a productive form for 5-lipoxygenation. The former, in a tail-first orientation, with the AA carboxylate end interacting with Lys409, gives the desired structures with C7 close to the Fe-OH(-) cofactor and suitable barrier heights for H7 abstraction. Only when using the apo form structure, a head-first orientation with the AA carboxylate close to His600 (a residue recently proposed as essential for AA positioning) is obtained in the docking calculations. However, the calculated barrier heights for this head-first orientation are in principle consistent with 5-LOX specificity, but also with 12/8 regioselectivity. Finally, long MD simulations give support to the recent hypothesis that the Phe177 + Tyr181 pair needs to close the active site access during the chemical reaction, and suggest that in the case of a head-first orientation Phe177 may be the residue interacting with the AA carboxylate. PMID:27489112

  15. Side-chain-to-tail cyclization of ribosomally derived peptides promoted by aryl and alkyl amino-functionalized unnatural amino acids.

    PubMed

    Frost, John R; Wu, Zhijie; Lam, Yick Chong; Owens, Andrew E; Fasan, Rudi

    2016-06-28

    A strategy for the production of side-chain-to-tail cyclic peptides from ribosomally derived polypeptide precursors is reported. Two genetically encodable unnatural amino acids, bearing either an aryl or alkyl amino group, were investigated for their efficiency toward promoting the formation of medium to large-sized peptide macrocycles via intein-mediated side-chain-to-C-terminus cyclization. While only partial cyclization was observed with precursor proteins containing para-amino-phenylalanine, efficient peptide macrocyclization could be achieved using O-2-aminoethyl-tyrosine as the reactive moiety. Conveniently, the latter was generated upon quantitative, post-translational reduction of the azido-containing counterpart, O-2-azidoethyl-tyrosine, directly in E. coli cells. This methodology could be successfully applied for the production of a 12 mer cyclic peptide with enhanced binding affinity for the model target protein streptavidin as compared to the acyclic counterpart (KD: 5.1 μM vs. 22.4 μM), thus demonstrating its utility toward the creation and investigation of novel, functional macrocyclic peptides. PMID:27064594

  16. A perspective of stepwise utilisation of Bayer red mud: Step two--Extracting and recovering Ti from Ti-enriched tailing with acid leaching and precipitate flotation.

    PubMed

    Huang, Yanfang; Chai, Wencui; Han, Guihong; Wang, Wenjuan; Yang, Shuzhen; Liu, Jiongtian

    2016-04-15

    The extraction and recovery of Ti from Ti-enriched tailing with acid leaching and precipitate flotation, as one of the critical steps, was proposed for the stepwise utilization of red mud. The factors influencing acid leaching and precipitate flotation were examined by factorial design. The leaching thermodynamics, kinetics of Ti(4+), Al(3+) and Fe(3+), and the mechanism of selectively Fe(3+) removal using [Hbet][Tf2N] as precipitating reagent were discussed. The extracting of Ti(4+), Al(3+) and Fe(3+) in concentrated H2SO4 is controlled by diffusion reactions, depending mainly upon leaching time and temperature. The maximum extracting efficiency of Ti(4+) is approximately 92.3%, whereas Al(3+) and Fe(3+) leaching are respectively 75.8% and 84.2%. [Hbet][Tf2N], as a precipitating reagent, operates through a coordination mechanism in flotation. The pH value is the key factor influencing the flotation recovery of Ti(4+), whereas the dosage of precipitating reagent is that for Al(3+) recovery. The maximum flotation recovery of Ti(4+) is 92.7%, whereas the maximum Al(3+) recovery is 93.5%. The total recovery rate for extracting and recovering titanium is 85.5%. The liquor with Ti(4+) of 15.5g/L, Al(3+) of 30.4g/L and Fe(3+) of 0.48g/L was obtained for the following hydrolysis step in the integrated process for red mud utilisation. PMID:26799223

  17. Effects of three low-molecular-weight organic acids (LMWOAs) and pH on the mobilization of arsenic and heavy metals (Cu, Pb, and Zn) from mine tailings.

    PubMed

    Wang, Suiling; Mulligan, Catherine N

    2013-02-01

    Natural organic acids may play an important role in influencing the mobility of toxic contaminants in the environment. The mobilization of arsenic (As) and heavy metals from an oxidized Pb-Zn mine tailings sample in the presence of three low-molecular-weight organic acids, aspartic acid, cysteine, and succinic acid, was investigated at a mass ratio of 10 mg organic additive/g mine tailings in this study. The effect of pH was also evaluated. The mine tailings sample, containing elevated levels of As (2,180 mg/kg), copper (Cu, 1,100 mg/kg), lead (Pb, 12,860 mg/kg), and zinc (Zn, 5,075 mg/kg), was collected from Bathurst, New Brunswick, Canada. It was found that the organic additives inhibited As and heavy metal mobilization under acidic conditions (at pH 3 or 5), but enhanced it under neutral to alkaline conditions (at pH above 7) through forming aqueous organic complexes. At pH 11, As, Cu, Pb, and Zn were mobilized mostly by the organic additives, 45, 46, 1,660, and 128 mg/kg by aspartic acid, 31, 28, 1,040, and 112 mg/kg by succinic acid, and 53, 38, 2,020, and 150 mg/kg by cysteine, respectively, whereas those by distilled water were 6, 16, 260, and 52 mg/kg, respectively. It was also found that the mobilization of As and the heavy metals was closely correlated, and both were closely correlated to Fe mobilization. Arsenic mobilization by the three LMWOAs was found to be consistent with the order of the stability of Fe-, Cu-, Pb-, and Zn-organic ligand complexes. The organic acids might be used potentially in the natural attenuation and remediation of As and heavy metal-contaminated sites. PMID:22648854

  18. Sialic acids and autoimmune disease.

    PubMed

    Mahajan, Vinay S; Pillai, Shiv

    2016-01-01

    An important underlying mechanism that contributes to autoimmunity is the loss of inhibitory signaling in the immune system. Sialic acid-recognizing Ig superfamily lectins or Siglecs are a family of cell surface proteins largely expressed in hematopoietic cells. The majority of Siglecs are inhibitory receptors expressed in immune cells that bind to sialic acid-containing ligands and recruit SH2-domain-containing tyrosine phosphatases to their cytoplasmic tails. They deliver inhibitory signals that can contribute to the constraining of immune cells, and thus protect the host from autoimmunity. The inhibitory functions of CD22/Siglec-2 and Siglec-G and their contributions to tolerance and autoimmunity, primarily in the B lymphocyte context, are considered in some detail in this review. The relevance to autoimmunity and unregulated inflammation of modified sialic acids, enzymes that modify sialic acid, and other sialic acid-binding proteins are also reviewed. PMID:26683151

  19. Cytoplasmic Domains and Voltage-Dependent Potassium Channel Gating

    PubMed Central

    Barros, Francisco; Domínguez, Pedro; de la Peña, Pilar

    2012-01-01

    The basic architecture of the voltage-dependent K+ channels (Kv channels) corresponds to a transmembrane protein core in which the permeation pore, the voltage-sensing components and the gating machinery (cytoplasmic facing gate and sensor–gate coupler) reside. Usually, large protein tails are attached to this core, hanging toward the inside of the cell. These cytoplasmic regions are essential for normal channel function and, due to their accessibility to the cytoplasmic environment, constitute obvious targets for cell-physiological control of channel behavior. Here we review the present knowledge about the molecular organization of these intracellular channel regions and their role in both setting and controlling Kv voltage-dependent gating properties. This includes the influence that they exert on Kv rapid/N-type inactivation and on activation/deactivation gating of Shaker-like and eag-type Kv channels. Some illustrative examples about the relevance of these cytoplasmic domains determining the possibilities for modulation of Kv channel gating by cellular components are also considered. PMID:22470342

  20. Chemical and mineralogical changes of waste and tailings from the Murgul Cu deposit (Artvin, NE Turkey): implications for occurrence of acid mine drainage.

    PubMed

    Sağlam, Emine Selva; Akçay, Miğraç

    2016-04-01

    Being one of the largest copper-producing resources in Turkey, the Murgul deposit has been a source of environmental pollution for very long time. Operated through four open pits with an annual production of about 3 million tons of ore at an average grade of about 0.5% Cu, the deposit to date has produced an enormous pile of waste (exceeding 100 million tons) with tailings composed of 36 % SiO2, 39% Fe2O3 and 32% S, mainly in the form of pyrite and quartz. Waters in the vicinity of the deposit vary from high acid-acid (2.71-3.85) and high-extremely metal rich (34.48-348.12 mg/l in total) in the open pits to near neutral (6.51-7.83) and low metal (14.39-973.52 μg/l in total) in downstream environments. Despite low metal contents and near neutral pH levels of the latter, their suspended particle loads are extremely high and composed mainly of quartz and clay minerals with highly elevated levels of Fe (3.5 to 24.5% Fe2O3; 11% on average) and S (0.5 to 20.6% S; 7% on average), showing that Fe is mainly in the form of pyrite and lesser hematite. They also contain high concentrations of As, Au, Ba, Cu, Pb, and Zn. Waters collected along the course of polluted drainages are supersaturated with respect to Fe phases such as goethite, hematite, maghemite, magnetite, schwertmannite and ferrihydrite. Secondary phases such as Fe-sulphates are only found near the pits, but not along the streams due to neutral pH conditions, where pebbles are covered and cemented by Fe-oxides and hydroxides indicating that oxidation of pyrite has taken place especially at times of low water load. It follows, then, that the pyrite-rich sediment load of streams fed by the waste of the Murgul deposit is currently a big threat to the aquatic life and environment and will continue to be so even after the closure of the deposit. In fact, the oxidation will be enhanced and acidity increased due to natural conditions, which necessitates strong remedial actions to be taken. PMID:26637995

  1. Tail biting in pigs.

    PubMed

    Schrøder-Petersen, D L; Simonsen, H B

    2001-11-01

    One of the costly and welfare-reducing problems in modern pig production is tail biting. Tail biting is an abnormal behaviour, characterized by one pig's dental manipulation of another pig's tail. Tail biting can be classified into two groups: the pre-injury stage, before any wound on the tail is present, and the injury stage, where the tail is wounded and bleeding. Tail biting in the injury stage will reduce welfare of the bitten pig and the possible spread of infection is a health as well as welfare problem. The pigs that become tail biters may also suffer, because they are frustrated due to living in a stressful environment. This frustration may result in an excessive motivation for biting the tails of pen mates. This review aims to summarize recent research and theories in relation to tail biting. PMID:11681870

  2. Environmental Factors Influencing the Structural Dynamics of Soil Microbial Communities During Assisted Phytostabilization of Acid-Generating Mine Tailings: a Mesocosm Experiment

    PubMed Central

    Valentín-Vargas, Alexis; Root, Robert A.; Neilson, Julia W; Chorover, Jon; Maier, Raina M.

    2014-01-01

    Compost-assisted phytostabilization has recently emerged as a robust alternative for reclamation of metalliferous mine tailings. Previous studies suggest that root-associated microbes may be important for facilitating plant establishment on the tailings, yet little is known about the long-term dynamics of microbial communities during reclamation. A mechanistic understanding of microbial community dynamics in tailings ecosystems undergoing remediation is critical because these dynamics profoundly influence both the biogeochemical weathering of tailings and the sustainability of a plant cover. Here we monitor the dynamics of soil microbial communities (i.e. bacteria, fungi, archaea) during a 12-month mesocosm study that included 4 treatments: 2 unplanted controls (unamended and compost-amended tailings) and 2 compost-amended seeded tailings treatments. Bacterial, fungal and archaeal communities responded distinctively to the revegetation process and concurrent changes in environmental conditions and pore water chemistry. Compost addition significantly increased microbial diversity and had an immediate and relatively long-lasting buffering-effect on pH, allowing plants to germinate and thrive during the early stages of the experiment. However, the compost buffering capacity diminished after six months and acidification took over as the major factor affecting plant survival and microbial community structure. Immediate changes in bacterial communities were observed following plant establishment, whereas fungal communities showed a delayed response that apparently correlated with the pH decline. Fluctuations in cobalt pore water concentrations, in particular, had a significant effect on the structure of all three microbial groups, which may be linked to the role of cobalt in metal detoxification pathways. The present study represents, to our knowledge, the first documentation of the dynamics of the three major microbial groups during revegetation of compost

  3. The Carboxyl Tail of Connexin32 Regulates Gap Junction Assembly in Human Prostate and Pancreatic Cancer Cells*

    PubMed Central

    Katoch, Parul; Mitra, Shalini; Ray, Anuttoma; Kelsey, Linda; Roberts, Brett J.; Wahl, James K.; Johnson, Keith R.; Mehta, Parmender P.

    2015-01-01

    Connexins, the constituent proteins of gap junctions, are transmembrane proteins. A connexin (Cx) traverses the membrane four times and has one intracellular and two extracellular loops with the amino and carboxyl termini facing the cytoplasm. The transmembrane and the extracellular loop domains are highly conserved among different Cxs, whereas the carboxyl termini, often called the cytoplasmic tails, are highly divergent. We have explored the role of the cytoplasmic tail of Cx32, a Cx expressed in polarized and differentiated cells, in regulating gap junction assembly. Our results demonstrate that compared with the full-length Cx32, the cytoplasmic tail-deleted Cx32 is assembled into small gap junctions in human pancreatic and prostatic cancer cells. Our results further document that the expression of the full-length Cx32 in cells, which express the tail-deleted Cx32, increases the size of gap junctions, whereas the expression of the tail-deleted Cx32 in cells, which express the full-length Cx32, has the opposite effect. Moreover, we show that the tail is required for the clustering of cell-cell channels and that in cells expressing the tail-deleted Cx32, the expression of cell surface-targeted cytoplasmic tail alone is sufficient to enhance the size of gap junctions. Our live-cell imaging data further demonstrate that gap junctions formed of the tail-deleted Cx32 are highly mobile compared with those formed of full-length Cx32. Our results suggest that the cytoplasmic tail of Cx32 is not required to initiate the assembly of gap junctions but for their subsequent growth and stability. Our findings suggest that the cytoplasmic tail of Cx32 may be involved in regulating the permeability of gap junctions by regulating their size. PMID:25548281

  4. Origin, development and ultrastructure of boar spermatozoa with folded tails and with two tails.

    PubMed

    Bonet, S; Briz, M; Fradera, A; Egozcue, J

    1992-04-01

    Spermatozoa from the three epididymal regions (head, body and tail) of healthy and sexually mature boars have been examined by light microscopy, and scanning and transmission electron microscopy. The origin, development and external and internal morphologies of aberrant spermatozoa with folded tails and spermatozoa with one or two heads and two fused tails have been established. A count carried out in each region of the epididymis indicated that significant differences (P less than 0.01) exist in the frequencies of each type of malformation and the epididymal region from which the spermatozoa come. Spermatozoa with folded tails at Jensen's ring originate in the cauda of the epididymis from immature spermatozoa that have not ejected the distal cytoplasmic droplet. The plasma membrane which covers the main piece is fused with the membranes of the midpiece, the connecting piece and the head. The fibrous sheath deforms the mitochondrial sheath and is placed between the plasma membrane and the postacrosomal dense lamina. Spermatozoa with one head and two fused tails originate in the epididymal body from spermatozoa with one head and two unfused tails coming from the cephalic region of the epididymis. Spermatozoa with two heads and two fused tails originate in the cephalic region of the epididymis by head-to-head agglutination of two spermatozoa and later fusion of their tails. The frequency of spermatozoa with two fused tails increases as they progress through the epididymal duct. Their tails, parallel in monocephalic spermatozoa and helicoid in bicephalic spermatozoa, have two complete axonemal axes. In their midpiece, the mitochondrial sheaths of the two axes are fused, producing an 8-shaped sheath. PMID:1522197

  5. Cytoplasmic determinants involved in direct lysosomal sorting, endocytosis, and basolateral targeting of rat lgp120 (lamp-I) in MDCK cells

    PubMed Central

    1995-01-01

    Rat lysosomal glycoprotein 120 (lgp120; lamp-I) is a transmembrane protein that is directly delivered from the trans-Golgi network (TGN) to the endosomal/lysosomal system without prior appearance on the cell surface. Its short cytosolic domain of 11 residues encodes determinants for direct lysosomal sorting, endocytosis and, in polarized cells, basolateral targeting. We now characterize the structural requirements in the cytosolic domain required for sorting of lgp120 into the different pathways. Our results show that the cytoplasmic tail is sufficient to mediate direct transport from the trans-Golgi network (TGN) to lysosomes and that a G7-Y8-X-X-I11 motif is crucial for this sorting event. While G7 is only critical for direct lysosomal sorting in the TGN, Y8 and I11 are equally important for lysosomal sorting, endocytosis, and basolateral targeting. Thus, a small motif of five amino acids in the cytoplasmic tail of lgp120 can be recognized by the sorting machinery at several cellular locations and direct the protein into a variety of intracellular pathways. PMID:7844146

  6. Cap homeostasis is independent of poly(A) tail length

    PubMed Central

    Kiss, Daniel L.; Oman, Kenji M.; Dougherty, Julie A.; Mukherjee, Chandrama; Bundschuh, Ralf; Schoenberg, Daniel R.

    2016-01-01

    Cap homeostasis is a cyclical process of decapping and recapping that maintains the cap on a subset of the cytoplasmic transcriptome. Interfering with cytoplasmic capping results in the redistribution of target transcripts from polysomes to non-translating mRNPs, where they accumulate in an uncapped but nonetheless stable form. It is generally thought that decapping is preceded by shortening of the poly(A) tail to a length that can no longer support translation. Therefore recapped target transcripts would either have to undergo cytoplasmic polyadenylation or retain a reasonably long poly(A) tail if they are to return to the translating pool. In cells that are inhibited for cytoplasmic capping there is no change in the overall distribution of poly(A) lengths or in the elution profile of oligo(dT)-bound targets. Poly(A) tail lengths were similar for target mRNAs on polysomes or in non-translating mRNPs, and the presence of polyadenylated uncapped mRNA in mRNPs was confirmed by separation into capped and uncapped pools prior to assay. Finally, in silico analysis of cytoplasmic capping targets revealed significant correlations with genes encoding transcripts with uridylated or multiply modified 3′ ends, and genes possessing multiple 3′-untranslated regions (UTRs) generated by alternative cleavage and polyadenylation. PMID:26673707

  7. Cytoplasmic Control of Sense-Antisense mRNA Pairs.

    PubMed

    Sinturel, Flore; Navickas, Albertas; Wery, Maxime; Descrimes, Marc; Morillon, Antonin; Torchet, Claire; Benard, Lionel

    2015-09-22

    Transcriptome analyses have revealed that convergent gene transcription can produce many 3'-overlapping mRNAs in diverse organisms. Few studies have examined the fate of 3'-complementary mRNAs in double-stranded RNA-dependent nuclear phenomena, and nothing is known about the cytoplasmic destiny of 3'-overlapping messengers or their impact on gene expression. Here, we demonstrate that the complementary tails of 3'-overlapping mRNAs can interact in the cytoplasm and promote post-transcriptional regulatory events including no-go decay (NGD) in Saccharomyces cerevisiae. Genome-wide experiments confirm that these messenger-interacting mRNAs (mimRNAs) form RNA duplexes in wild-type cells and thus have potential roles in modulating the mRNA levels of their convergent gene pattern under different growth conditions. We show that the post-transcriptional fate of hundreds of mimRNAs is controlled by Xrn1, revealing the extent to which this conserved 5'-3' cytoplasmic exoribonuclease plays an unexpected but key role in the post-transcriptional control of convergent gene expression. PMID:26344770

  8. Electrodialytic remediation of copper mine tailings.

    PubMed

    Hansen, Henrik K; Rojo, Adrián; Ottosen, Lisbeth M

    2005-01-31

    Mining activities in Chile have generated large amounts of solid waste, which have been deposited in mine tailing impoundments. These impoundments cause concern to the communities due to dam failures or natural leaching to groundwater and rivers. This work shows the laboratory results of nine electrodialytic remediation experiments on copper mine tailings. The results show that electric current could remove copper from watery tailing if the potential gradient was higher than 2 V/cm during 21 days. With addition of sulphuric acid, the process was enhanced because the pH decreased to around 4, and the copper by this reason was released in the solution. Furthermore, with acidic tailing the potential gradient was less than 2 V/cm. The maximum copper removal reached in the anode side was 53% with addition of sulphuric acid in 21 days experiment at 20 V using approximately 1.8 kg mine tailing on dry basis. In addition, experiments with acidic tailing show that the copper removal is proportional with time. PMID:15629576

  9. Sorting by the cytoplasmic domain of the amyloid precursor protein binding receptor SorLA.

    PubMed

    Nielsen, Morten S; Gustafsen, Camilla; Madsen, Peder; Nyengaard, Jens R; Hermey, Guido; Bakke, Oddmund; Mari, Muriel; Schu, Peter; Pohlmann, Regina; Dennes, André; Petersen, Claus M

    2007-10-01

    SorLA/LR11 (250 kDa) is the largest and most composite member of the Vps10p-domain receptors, a family of type 1 proteins preferentially expressed in neuronal tissue. SorLA binds several ligands, including neurotensin, platelet-derived growth factor-bb, and lipoprotein lipase, and via complex-formation with the amyloid precursor protein it downregulates generation of Alzheimer's disease-associated Abeta-peptide. The receptor is mainly located in vesicles, suggesting a function in protein sorting and transport. Here we examined SorLA's trafficking using full-length and chimeric receptors and find that its cytoplasmic tail mediates efficient Golgi body-endosome transport, as well as AP-2 complex-dependent endocytosis. Functional sorting sites were mapped to an acidic cluster-dileucine-like motif and to a GGA binding site in the C terminus. Experiments in permanently or transiently AP-1 mu1-chain-deficient cells established that the AP-1 adaptor complex is essential to SorLA's transport between Golgi membranes and endosomes. Our results further implicate the GGA proteins in SorLA trafficking and provide evidence that SNX1 and Vps35, as parts of the retromer complex or possibly in a separate context, are engaged in retraction of the receptor from endosomes. PMID:17646382

  10. Clean tailing reclamation: Tailing reprocessing for sulfide removal and vegetation establishment

    SciTech Connect

    Jennings, S.R.; Kruegar, J.

    1997-12-31

    Mine wastes exhibiting elevated heavy metal concentrations are widespread causes of resource degradation in the western US and elsewhere. This problem is further exacerbated by the presence of pyrite that oxidizes upon exposure to the atmosphere resulting in acid generation. Since pyrite was not recovered as a mineral of economic value during mining, it was disposed of in waste piles and tailing ponds that are now a source of acid generation and release of metals to the environment. Tailing cleaning, or sulfide mineral recovery through reprocessing, was evaluated as an innovative reclamation technology. Tailing materials, from both operational and abandoned mines, were collected to evaluate the feasibility of sulfide mineral recovery. Successful mineral separation was performed resulting in a low volume metal sulfide concentrate and a high volume cleaned silicate media. Total metal concentrations were decreased in the cleaned tailing material and elevated in the sulfide concentrate compared with the original tailing chemistry. In greenhouse trials, vegetation establishment in cleaned tailing material was compared with plant growth in topsoil and lime-amended tailings. While vegetation performance was best in the topsoil control, both lime-amended and cleaned tailings displayed adequate plant growth.

  11. Isolation of Cytoplasmic Enzymes from Pollen 1

    PubMed Central

    Weeden, Norman F.; Gottlieb, Leslie D.

    1980-01-01

    The cytoplasmic isozyme of many cytoplasmic-organelle isozyme pairs, as well as other cytoplasmic enzymes in plants, can be readily obtained from pollen by soaking it in an appropriate buffer for 4 hours. Enzymes localized in subcellular organelles appear not to be released during the soaking period, although they are released if the pollen is crushed. The technique is a useful initial step in studies of subcellular localization of enzymes or for obtaining small quantities of cytoplasmic enzymes free of organellar contaminants. Images PMID:16661444

  12. Extracting aluminum from dross tailings

    NASA Astrophysics Data System (ADS)

    Amer, A. M.

    2002-11-01

    Aluminum dross tailings, an industrial waste, from the Egyptian Aluminium Company (Egyptalum) was used to produce two types of alums: aluminum-sulfate alum [itAl2(SO4)3.12H2O] and ammonium-aluminum alum [ (NH 4)2SO4AL2(SO4)3.24H2O]. This was carried out in two processes. The first process is leaching the impurities using diluted H2SO4 with different solid/liquid ratios at different temperatures to dissolve the impurities present in the starting material in the form of solute sulfates. The second process is the extraction of aluminum (as aluminum sulfate) from the purifi ed aluminum dross tailings thus produced. The effects of temperature, time of reaction, and acid concentration on leaching and extraction processes were studied. The product alums were analyzed using x-ray diffraction and thermal analysis techniques.

  13. The kinase domain of mitochondrial PINK1 faces the cytoplasm

    PubMed Central

    Zhou, Chun; Huang, Yong; Shao, Yufang; May, Jessica; Prou, Delphine; Perier, Celine; Dauer, William; Schon, Eric A.; Przedborski, Serge

    2008-01-01

    Mutations in PTEN-induced putative kinase 1 (PINK1) are a cause of autosomal recessive familial Parkinson's disease (PD). Efforts in deducing the PINK1 signaling pathway have been hindered by controversy around its subcellular and submitochondrial localization and the authenticity of its reported substrates. We show here that this mitochondrial protein exhibits a topology in which the kinase domain faces the cytoplasm and the N-terminal tail is inside the mitochondria. Although deletion of the transmembrane domain disrupts this topology, common PD-linked PINK1 mutations do not. These results are critical in rectifying the location and orientation of PINK1 in mitochondria, and they should help decipher its normal physiological function and potential pathogenic role in PD. PMID:18687899

  14. Evidence for bacteriophage T7 tail extension during DNA injection

    PubMed Central

    Serwer, Philip; Wright, Elena T; Hakala, Kevin W; Weintraub, Susan T

    2008-01-01

    Background Electron micrographs of bacteriophage T7 reveal a tail shorter than needed to reach host cytoplasm during infection-initiating injection of a T7 DNA molecule through the tail and cell envelope. However, recent data indicate that internal T7 proteins are injected before the DNA molecule is injected. Thus, bacteriophage/host adsorption potentially causes internal proteins to become external and lengthen the tail for DNA injection. But, the proposed adsorption-induced tail lengthening has never been visualized. Findings In the present study, electron microscopy of particles in T7 lysates reveals a needle-like capsid extension that attaches partially emptied bacteriophage T7 capsids to non-capsid vesicles and sometimes enters an attached vesicle. This extension is 40–55 nm long, 1.7–2.4× longer than the T7 tail and likely to be the proposed lengthened tail. The extension is 8–11 nm in diameter, thinner than most of the tail, with an axial hole 3–4 nm in diameter. Though the bound vesicles are not identified by microscopy, these vesicles resemble the major vesicles in T7 lysates, found to be E. coli outer membrane vesicles by non-denaturing agarose gel electrophoresis, followed by mass spectrometry. Conclusion The observed lengthened tail is long enough to reach host cytoplasm during DNA injection. Its channel is wide enough to be a conduit for DNA injection and narrow enough to clamp DNA during a previously observed stalling/re-starting of injection. However, its outer diameter is too large to explain formation by passing of an intact assembly through any known capsid hole unless the hole is widened. PMID:18710489

  15. Measurement of Cytoplasmic Streaming in Drosophila Melanogaster

    NASA Astrophysics Data System (ADS)

    Ganguly, Sujoy; Williams, Lucy; Palacios, Isabel; Goldstein, Raymond

    2010-11-01

    During stage 9 of Drosophila melanogastor oogenesis flow of the oocyte cytoplasm, driven by kinesin 1 motor protein is observed. This cytoplasmic streaming is analyzed by PIV in both wild type and kinesin light chain mutants, revealing striking statistical differences. Further measurements of the rheology of the oocyte allow for estimations of the mechanical energy needed to generate the observed flows.

  16. Cytoplasmic alkalization reduces calcium buffering in molluscan central neurons.

    PubMed

    Zucker, R S

    1981-11-23

    The effect of raised cytoplasmic pH (pHi) on intracellular concentration ([Ca2+]i) transients following calcium influx during membrane depolarization was studied in identified neurons in the abdominal ganglion of Aplysia californica. The pHi was monitored with pH-sensitive microelectrodes. Sea water containing 15 mM NH4Cl at pH 7.7 elevated pHi about 0.35 pH units from the normal level of 7.17. These cells have an estimated buffering power of about 60 mM/pH unit. Calcium influx was elicited by depolarizing pulses under voltage clamp and [Ca2+]i transients were monitored with the photoprotein aequorin or the metallochromic dye arsenazo III. Aequorin photo-emissions increased by 21--131% (mean, 48%) and arsenazo III absorbance changes accompanying depolarization increased by 9--33% (mean, 20%) after 30 min in NH4+, corresponding roughly to a 14% increase in [Ca2+]i transients. Calcium-dependent potassium tail currents following a depolarizing pulse were somewhat slower and 4--91% (mean, 38%) large in NH4+. The magnitude and time- and voltage-dependence of the membrane calcium conductance was studied using calcium tail currents following depolarizing pulses. The calcium current was unaffected by NH4+, so the enhanced [Ca2+]i transients must reflect reduced calcium buffering at high pHi. Either reduced cytoplasmic calcium binding or slowed active extrusion of calcium may be responsible for this effect. PMID:6271335

  17. Efficient expression of full-length antibodies in the cytoplasm of engineered bacteria

    PubMed Central

    Robinson, Michael-Paul; Ke, Na; Lobstein, Julie; Peterson, Cristen; Szkodny, Alana; Mansell, Thomas J.; Tuckey, Corinna; Riggs, Paul D.; Colussi, Paul A.; Noren, Christopher J.; Taron, Christopher H.; DeLisa, Matthew P.; Berkmen, Mehmet

    2015-01-01

    Current methods for producing immunoglobulin G (IgG) antibodies in engineered cells often require refolding steps or secretion across one or more biological membranes. Here, we describe a robust expression platform for biosynthesis of full-length IgG antibodies in the Escherichia coli cytoplasm. Synthetic heavy and light chains, both lacking canonical export signals, are expressed in specially engineered E. coli strains that permit formation of stable disulfide bonds within the cytoplasm. IgGs with clinically relevant antigen- and effector-binding activities are readily produced in the E. coli cytoplasm by grafting antigen-specific variable heavy and light domains into a cytoplasmically stable framework and remodelling the fragment crystallizable domain with amino-acid substitutions that promote binding to Fcγ receptors. The resulting cytoplasmic IgGs—named ‘cyclonals'—effectively bypass the potentially rate-limiting steps of membrane translocation and glycosylation. PMID:26311203

  18. Cytoplasmic Streaming - Skylab Student Experiment ED-63

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This chart describes the Skylab student experiment (ED-63), Cytoplasmic Streaming, proposed by Cheryl A. Peitz of Arapahoe High School, Littleton, Colorado. Experiment ED-63 was to observe the effect of zero-gravity on cytoplasmic streaming in the aquatic plant named Elodea, commonly called water weed or water thyme. The phenomenon of cytoplasmic streaming is not well understood, but it is recognized as the circulation mechanism of the internal materials or cytoplasm of a cell. Cytoplasm is a gelatinous substance that has the ability to change its viscosity and flow, carrying various cell materials with it. The activity can be stimulated by sunlight or heat. In March 1972, NASA and the National Science Teachers Association selected 25 experiment proposals for flight on Skylab. Science advisors from the Marshall Space Flight Center aided and assisted the students in developing the proposals for flight on Skylab.

  19. Indanylacetic acid derivatives carrying 4-thiazolyl-phenoxy tail groups, a new class of potent PPAR alpha/gamma/delta pan agonists: synthesis, structure-activity relationship, and in vivo efficacy.

    PubMed

    Rudolph, Joachim; Chen, Libing; Majumdar, Dyuti; Bullock, William H; Burns, Michael; Claus, Thomas; Dela Cruz, Fernando E; Daly, Michelle; Ehrgott, Frederick J; Johnson, Jeffrey S; Livingston, James N; Schoenleber, Robert W; Shapiro, Jeffrey; Yang, Ling; Tsutsumi, Manami; Ma, Xin

    2007-03-01

    Compounds that simultaneously activate the three peroxisome proliferator-activated receptor (PPAR) subtypes alpha, gamma, and delta hold potential to address the adverse metabolic and cardiovascular conditions associated with diabetes and the metabolic syndrome. We recently identified the indanylacetic acid moiety as a well-tunable PPAR agonist head group. Here we report the synthesis and structure-activity relationship (SAR) studies of novel aryl tail group derivatives that led to a new class of potent PPAR pan agonists. While most of the tail group modifications imparted potent PPAR delta agonist activity, improvement of PPAR alpha and gamma activity required the introduction of new heterocyclic substituents that were not known in the PPAR literature. Systematic optimization led to the discovery of 4-thiazolyl-phenyl derivatives with potent PPAR alpha/gamma/delta pan agonistic activity. The lead candidate from this series was found to exhibit excellent ADME properties and superior therapeutic potential compared to known PPAR gamma activating agents by favorably modulating lipid levels in hApoA1 mice and hyperlipidemic hamsters, while normalizing glucose levels in diabetic rodent models. PMID:17274610

  20. Cytoplasmic pathway followed by chloride ions to enter the CFTR channel pore.

    PubMed

    El Hiani, Yassine; Negoda, Alexander; Linsdell, Paul

    2016-05-01

    Most ATP-binding cassette (ABC) proteins function as ATP-dependent membrane pumps. One exception is the cystic fibrosis transmembrane conductance regulator (CFTR), an ABC protein that functions as a Cl(-) ion channel. As such, the CFTR protein must form a continuous pathway for the movement of Cl(-) ions from the cytoplasm to the extracellular solution when in its open channel state. Extensive functional investigations have characterized most parts of this Cl(-) permeation pathway. However, one region remains unexplored-the pathway connecting the cytoplasm to the membrane-spanning pore. We used patch clamp recording and extensive substituted cysteine accessibility mutagenesis to identify amino acid side-chains in cytoplasmic regions of CFTR that lie close to the pathway taken by Cl(-) ions as they pass from the cytoplasm through this pathway. Our results suggest that Cl(-) ions enter the permeation pathway via a single lateral tunnel formed by the cytoplasmic parts of the protein, and then follow a fairly direct central pathway towards the membrane-spanning parts of the protein. However, this pathway is not lined continuously by any particular part of the protein; instead, the contributions of different cytoplasmic regions of the protein appear to change as the permeation pathway approaches the membrane, which appears to reflect the ways in which different cytoplasmic regions of the protein are oriented towards its central axis. Our results allow us to define for the first time the complete Cl(-) permeation pathway in CFTR, from the cytoplasm to the extracellular solution. PMID:26659082

  1. Deep cytoplasmic rearrangements in ventralized Xenopus embryos

    NASA Technical Reports Server (NTRS)

    Brown, E. E.; Denegre, J. M.; Danilchik, M. V.

    1993-01-01

    Following fertilization in Xenopus, dramatic rearrangements of the egg cytoplasm relocalize maternally synthesized egg components. During the first cell cycle the vegetal yolk mass rotates relative to the egg surface, toward the sperm entry point (SEP) (J. P. Vincent, G. F. Oster, and J. C. Gerhart, 1986, Dev. Biol. 113, 484-500), while concomitant deep cytoplasmic rearrangements occur in the animal hemisphere (M. V. Danilchik and J. M. Denegre, 1991, Development 111, 845-856). In this paper we examine the role of vegetal yolk mass rotation in producing the animal cytoplasmic rearrangements. We inhibited rotation by uv-irradiating embryos during the first cell cycle, a treatment that yields an extremely ventralized phenotype. Both uv-irradiated embryos and unirradiated control embryos show cytoplasmic rearrangements in the animal hemisphere during the first cell cycle. Cytoplasmic rearrangements on the SEP side of the embryo associated with the path of the sperm pronucleus, plus a swirl on the anti-SEP (dorsal) side, are seen, whether or not yolk mass rotation has occurred. This result suggests a role for the expanding sperm aster in directing animal hemisphere cytoplasmic movements. In unirradiated control embryos the anti-SEP (dorsal) swirl is larger than that in uv-irradiated embryos and often extends into the vegetal hemisphere, consistent with the animal cytoplasm having been pulled dorsally and vegetally by the sliding vegetal yolk mass. Thus the yolk mass rotation may normally enhance the dorsalward cytoplasmic movement, begun by the sperm aster, enough to induce normal axis formation. We extended our observations of unirradiated control and uv-irradiated embryos through early cleavages. The vegetal extent of the anti-SEP (dorsal) swirl pattern seen in control embryos persists through the early cleavage period, such that labeled animal cytoplasm extends deep into dorsal third-tier blastomeres at the 32-cell stage. Significantly, in uv-irradiated embryos

  2. The Tail of BPM

    NASA Astrophysics Data System (ADS)

    Kruba, Steve; Meyer, Jim

    Business process management suites (BPMS's) represent one of the fastest growing segments in the software industry as organizations automate their key business processes. As this market matures, it is interesting to compare it to Chris Anderson's 'Long Tail.' Although the 2004 "Long Tail" article in Wired magazine was primarily about the media and entertainment industries, it has since been applied (and perhaps misapplied) to other markets. Analysts describe a "Tail of BPM" market that is, perhaps, several times larger than the traditional BPMS product market. This paper will draw comparisons between the concepts in Anderson's article (and subsequent book) and the BPM solutions market.

  3. Uranium mill tailings neutralization: contaminant complexation and tailings leaching studies

    SciTech Connect

    Opitz, B.E.; Dodson, M.E.; Serne, R.J.

    1985-05-01

    Laboratory experiments were performed to compare the effectiveness of limestone (CaCO/sub 3/) and hydrated lime (Ca(OH)/sub 2/) for improving waste water quality through the neutralization of acidic uranium mill tailings liquor. The experiments were designed to also assess the effects of three proposed mechanisms - carbonate complexation, elevated pH, and colloidal particle adsorption - on the solubility of toxic contaminants found in a typical uranium mill waste solution. Of special interest were the effects each of these possible mechanisms had on the solution concentrations of trace metals such as Cd, Co, Mo, Zn, and U after neutralization. Results indicated that the neutralization of acidic tailings to a pH of 7.3 using hydrated lime provided the highest overall waste water quality. Both the presence of a carbonate source or elevating solution pH beyond pH = 7.3 resulted in a lowering of previously achieved water quality, while adsorption of contaminants onto colloidal particles was not found to affect the solution concentration of any constituent investigated. 24 refs., 8 figs., 19 tabs.

  4. Cytoplasmic rearrangements associated with amphibian egg symmetrization

    NASA Technical Reports Server (NTRS)

    Malacinski, G. M.

    1984-01-01

    Cytoplasmic rearrangements which follow fertilization were mentioned in normal and inverted eggs. A set of yolk compartments was resolved by cytological analyses of both normally oriented and inverted eggs. Those compartments were characterized by their yolk platelet compositions and movement during egg inversion. It is found that during egg inversion the yolk compartments shift minor cytoplasmic compartments which line the egg cortex. Those yolk mass shifts occurred only after the inverted egg was activated. The direction of shift of the major yolk components, rather than the sperm entrance site, determines the dorsal/ventral polarity of the inverted egg. Among different spawnings the rate of shift varied. Eggs that displayed the fastest rate of shift exhibited the highest frequency of developmental abnormalities during organogenesis. Interpretation of novel observations on cytoplasmic organization provide criticism of some earlier models. A new density compartment model is presented as a coherent way to view the organization of the egg cytoplasm and the development of bilateral symmetry.

  5. Wagging tail vibration absorber

    NASA Technical Reports Server (NTRS)

    Barclay, R. G.; Humphrey, P. W.

    1969-01-01

    A 750-foot cantilever length of extendible-tape boom (very low stiffness) was considered as the main system to be damped. A number of tail lengths were tried from 20 feet to 80 feet after which 40 feet was investigated further as a desirable compromise between performance and practical lengths. A 40-foot damping tail produced a damping effect on the main boom for the first mode equivalent in decay rate to 3.1 percent of critical damping. In this case the spring-hinge and tail were tuned to the main boom first mode frequency and the hinge damping was set at 30 percent of critical based on the tail properties. With this same setting, damping of the second mode was .4 percent and the third mode .1 percent.

  6. An osmotic system within the cytoplasm of cells.

    PubMed

    OPIE, E L

    1948-05-01

    The cytoplasm of cells of the liver and of the kidney is in large part occupied by bodies which respond to the water content of these cells and are modified by dissolved substances in the surrounding fluid or by physical change such as freezing. These bodies, in part mitochondria but designated more broadly cytochondria, constitute an osmotic system within the cytoplasm of cells. When the specific gravity of liver or kidney tissue is used as an index of changes in the water content of tissue, swelling of cytochondria in general follows the intake of water but this relation may be modified by a variety of conditions. When liver that has been frozen and thawed is immersed in water, cytochondria become swollen though the containing cells diminish in size. Solutions of sodium and of potassium chloride isotonic with blood plasma cause delayed swelling of cells and cytochondria, greater with the potassium salt; solutions of calcium chloride of equal molar concentration cause immediate swelling of cells and cytochondria. The basophile material of the cytoplasm (ribonucleic acid and related substances) and the material that gives to mitochondria their characteristic stain are removed by immersion in water but their disappearance is retarded by isotonic solutions of sodium or of potassium chloride and further delayed by hypertonic solutions. When the intensity of staining reactions is diminished by the partial loss of basophile substance or of the distinctive mitochondrial material, these are found at the surfaces of the cytoplasmic bodies, held perhaps by adsorption. When water, isotonic solutions of sodium chloride, or Ringer's solution comes into contact with immersed liver, they remove basophile and mitochondrial material from a superficial zone and substances with similar staining reactions appear in the cytoplasm of cells at a deeper level. Osmotic changes in the cytoplasmic bodies may be reversible. When liver tissue which has been for a short time immersed in water

  7. Cytoplasmic Acidification Induced by Inorganic Phosphate Uptake in Suspension Cultured Catharanthus roseus Cells

    PubMed Central

    Sakano, Katsuhiro; Yazaki, Yoshiaki; Mimura, Tetsuro

    1992-01-01

    Cytoplasmic acidification during inorganic phosphate (Pi) absorption by Catharanthus roseus cells were studied by means of a fluorescent pH indicator, 2′,7′-bis-(2-carboxyethyl)-5 carboxyfluorescein (acetomethylester) (BCECF), and 31P-nuclear magnetic resonance spectroscopy. Cytoplasmic acidification measured by decrease in the fluorescence intensity started immediately after Pi application. Within a minute or so, a stable state was attained and no further acidification occurred, whereas Pi absorption was still proceeding. As soon as Pi in the medium was exhausted, cytoplasmic pH started to recover. Coincidentally, the medium pH started to recover toward the original acidic pH. The Pi-induced changes in the cytoplasmic pH were confirmed by 31P-nuclear magnetic resonance study. Maximum acidification of the cytoplasm induced by 1.7 millimolar Pi was 0.2 pH units. Vacuolar pH was also affected by Pi. In some experiments, but not all, pH decreased reversibly by 0.2 to 0.3 pH units during Pi absorption. Results suggest that the cytoplasmic pH is regulated by proton pumps in the plasma membrane and in the tonoplast. In addition, other mechanisms that could consume extra protons in the cytoplasm are suggested. ImagesFigure 1 PMID:16668939

  8. Apoptosis-induced mitochondrial dysfunction causes cytoplasmic lipid droplet formation.

    PubMed

    Boren, J; Brindle, K M

    2012-09-01

    A characteristic of apoptosis is the rapid accumulation of cytoplasmic lipid droplets, which are composed largely of neutral lipids. The proton signals from these lipids have been used for the non-invasive detection of cell death using magnetic resonance spectroscopy. We show here that despite an apoptosis-induced decrease in the levels and activities of enzymes involved in lipogenesis, which occurs downstream of p53 activation and inhibition of the mTOR signaling pathway, the increase in lipid accumulation is due to increased de novo lipid synthesis. This results from inhibition of mitochondrial fatty acid β-oxidation, which coupled with an increase in acyl-CoA synthetase activity, diverts fatty acids away from oxidation and into lipid synthesis. The inhibition of fatty acid oxidation can be explained by a rapid rise in mitochondrial membrane potential and an attendant increase in the levels of reactive oxygen species. PMID:22460322

  9. The mechanics of motility in dissociated cytoplasm.

    PubMed Central

    Dembo, M

    1986-01-01

    We stimulate the dynamical behavior of dissociated cytoplasm using the Reactive Flow Model (Dembo, M., and F. Harlow, 1986, Biophys. J., 50:109-121). We find that for the most part the predicted dynamical behavior of the cytoplasm is governed by three nondimensional numbers. Several other nondimensional parameters, the initial conditions, and boundary conditions are found to have lesser effects. Of the three major nondimensional parameters, one (D#) controls the percentage of ectoplasm, the second (C#) controls the sharpness of the endoplasm-ectoplasm boundary, and the third (R#) controls the topological complexity of the endoplasm-ectoplasm distribution. If R# is very small, then the cytoplasm contracts into a single uniform mass, and there is no bulk streaming. If R# is very large, then the cytoplasmic mass breaks up into a number of clumps scattered throughout the available volume. Between these clumps the solution undergoes turbulent or chaotic patterns of streaming. Intermediate values of R# can be found such that the mass of cytoplasm remains connected and yet undergoes coherent modes of motility similar to flares (Taylor, D.L., J.S. Condeelis, P.L. Moore, and R.D. Allen, 1973, J. Cell Biol., 59:378-394) and rosettes (Kuroda, K., 1979, Cell Motility: Molecules and Organization, 347-362). Images FIGURE 1 FIGURE 1B FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 PMID:3801576

  10. Cytoplasmic Acidification and Secondary Metabolite Production in Different Plant Cell Suspensions (A Comparative Study).

    PubMed Central

    Hagendoorn, MJM.; Wagner, A. M.; Segers, G.; Van Der Plas, LHW.; Oostdam, A.; Van Walraven, H. S.

    1994-01-01

    In this study, a correlation is described between low cytoplasmic pH, measured with the fluorescent probes 2[prime],7[prime]-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (acetoxymethyl ester) and bis- [3-propyl-5-oxoisoxazol-4-yl]pentamethine oxonol, and the production of secondary metabolites for several plant cell-suspension systems. Anthraquinone production in Morinda citrifolia suspensions is negligible in the presence of 2,4-dichlorophenoxyacetic acid (2,4-D), whereas with naphthalene acetic acid (NAA) a significant accumulation is realized. NAA-grown cells showed a lower cytoplasmic pH than did 2,4-D-grown cells. Addition of 2,4-D or parachlorophenoxy acetic acid to NAA-grown cells resulted in an inhibition of anthraquinone production and an increase of the cytoplasmic pH, whereas addition of parachlorophenyl acetic acid had no effect on either parameter. Lignin production in Petunia hybrida cells could be induced by subculturing them in a medium without iron. These cells showed a lower cytoplasmic pH than control cells. Addition of Fe3+ led to a decreased lignin content and an increased cytoplasmic pH. Two cell lines of Linum flavum showed a different level of coniferin and lignin concentration in their cells. Cells that accumulated coniferin and lignin had a lower cytoplasmic pH than cells that did not accumulate these secondary metabolites. Apparently, in different species and after different kinds of treatment there is a correlation between acidification of the cytoplasm and the production of different secondary metabolites. The possible role of this acidification in secondary metabolite production is discussed. PMID:12232364

  11. Acidic phospholipids govern the enhanced activation of IgG-B cell receptor

    PubMed Central

    Chen, Xiangjun; Pan, Weiling; Sui, Yinqiang; Li, Hua; Shi, Xiaoshan; Guo, Xingdong; Qi, Hai; Xu, Chenqi; Liu, Wanli

    2015-01-01

    B cells that express the isotype-switched IgG-B cell receptor (IgG-BCR) are one of the driving forces for antibody memory. To allow for a rapid memory IgG antibody response, IgG-BCR evolved into a highly effective signalling machine. Here, we report that the positively charged cytoplasmic domain of mIgG (mIgG-tail) specifically interacts with negatively charged acidic phospholipids. The key immunoglobulin tail tyrosine (ITT) in mIgG-tail is thus sequestered in the membrane hydrophobic core in quiescent B cells. Pre-disruption of such interaction leads to excessive recruitment of BCRs and inflated BCR signalling upon antigen stimulation, resulting in hyperproliferation of primary B cells. Physiologically, membrane-sequestered mIgG-tail can be released by antigen engagement or Ca2+ mobilization in the initiation of B cell activation. Our studies suggest a novel regulatory mechanism for how dynamic association of mIgG-tail with acidic phospholipids governs the enhanced activation of IgG-BCR. PMID:26440273

  12. Xenopus egg cytoplasm with intact actin.

    PubMed

    Field, Christine M; Nguyen, Phuong A; Ishihara, Keisuke; Groen, Aaron C; Mitchison, Timothy J

    2014-01-01

    We report optimized methods for preparing Xenopus egg extracts without cytochalasin D, that we term "actin-intact egg extract." These are undiluted egg cytoplasm that contains abundant organelles, and glycogen which supplies energy, and represents the least perturbed cell-free cytoplasm preparation we know of. We used this system to probe cell cycle regulation of actin and myosin-II dynamics (Field et al., 2011), and to reconstitute the large, interphase asters that organize early Xenopus embryos (Mitchison et al., 2012; Wühr, Tan, Parker, Detrich, & Mitchison, 2010). Actin-intact Xenopus egg extracts are useful for analysis of actin dynamics, and interaction of actin with other cytoplasmic systems, in a cell-free system that closely mimics egg physiology, and more generally for probing the biochemistry and biophysics of the egg, zygote, and early embryo. Detailed protocols are provided along with assays used to check cell cycle state and tips for handling and storing undiluted egg extracts. PMID:24630119

  13. Cytoplasmic pH influences cytoplasmic calcium in MC3T3-E1 osteoblast cells

    NASA Technical Reports Server (NTRS)

    Lin, H. S.; Hughes-Fulford, M.; Kumegawa, M.; Pitts, A. C.; Snowdowne, K. W.

    1993-01-01

    We found that the cytoplasmic concentration of calcium (Cai) of MC3T3-E1 osteoblasts was influenced by the type of pH buffer we used in the perfusing medium, suggesting that intracellular pH (pHi) might influence Cai. To study this effect, the Cai and pHi were monitored as we applied various experimental conditions known to change pHi. Exposure to NH4Cl caused a transient increase in both pHi and Cai without a change in extracellular pH (pHo). Decreasing pHo and pHi by lowering the bicarbonate concentration of the medium decreased Cai, and increasing pHi by the removal of 5% CO2 increased Cai. Clamping pHi to known values with 10 microM nigericin, a potassium proton ionophore, also influenced Cai: acid pHi lowered Cai, whereas alkaline pHi increased it. The rise in Cai appears to be very sensitive to the extracellular concentration of calcium, suggesting the existence of a pH-sensitive calcium influx mechanism. We conclude that physiologic changes in pH could modulate Cai by controlling the influx of calcium ions and could change the time course of the Cai transient associated with hormonal activation.

  14. How crowded is the prokaryotic cytoplasm?

    PubMed

    Spitzer, Jan; Poolman, Bert

    2013-07-11

    We consider biomacromolecular crowding within the cytoplasm of prokaryotic cells as a two-phase system of 'supercrowded' cytogel and 'dilute' cytosol; we simplify and quantify this model for a coccoid cell over a wide range of biomacromolecular crowding. The key result shows that the supercrowded cytogel extends the vectorial character of the plasma membrane deeper into the cytoplasm by about 20-70 nm. We discuss useful physiological insights that this model gives into the functioning of a prokaryotic cell on the micrometer scale. PMID:23735698

  15. Consequences of Cytoplasmic Irradiation: Studies from Microbeam

    PubMed Central

    Zhou, Hongning; Hong, Mei; Chai, Yunfei; Hei, Tom K.

    2013-01-01

    The prevailing dogma for radiation biology is that genotoxic effects of ionizing radiation such as mutations and carcinogenesis are attributed mainly to direct damage to the nucleus. However, with the development of microbeam that can target precise positions inside the cells, accumulating evidences have shown that energy deposit by radiation in nuclear DNA is not required to trigger the damage, extra-nuclear or extra-cellular radiation could induce the similar biological effects as well. This review will summarize the biological responses after cytoplasm irradiated by microbeam, and the possible mechanisms involved in cytoplasmic irradiation. PMID:19346686

  16. Pro-autophagic polyphenols reduce the acetylation of cytoplasmic proteins

    PubMed Central

    Pietrocola, Federico; Mariño, Guillermo; Lissa, Delphine; Vacchelli, Erika; Malik, Shoaib Ahmad; Niso-Santano, Mireia; Zamzami, Naoufal; Galluzzi, Lorenzo; Maiuri, Maria Chiara; Kroemer, Guido

    2012-01-01

    Resveratrol is a polyphenol contained in red wine that has been amply investigated for its beneficial effects on organismal metabolism, in particular in the context of the so-called “French paradox,” i.e., the relatively low incidence of coronary heart disease exhibited by a population with a high dietary intake of cholesterol and saturated fats. At least part of the beneficial effect of resveratrol on human health stems from its capacity to promote autophagy by activating the NAD-dependent deacetylase sirtuin 1. However, the concentration of resveratrol found in red wine is excessively low to account alone for the French paradox. Here, we investigated the possibility that other mono- and polyphenols contained in red wine might induce autophagy while affecting the acetylation levels of cellular proteins. Phenolic compounds found in red wine, including anthocyanins (oenin), stilbenoids (piceatannol), monophenols (caffeic acid, gallic acid) glucosides (delphinidin, kuronamin, peonidin) and flavonoids (catechin, epicatechin, quercetin, myricetin), were all capable of stimulating autophagy, although with dissimilar potencies. Importantly, a robust negative correlation could be established between autophagy induction and the acetylation levels of cytoplasmic proteins, as determined by a novel immunofluorescence staining protocol that allows for the exclusion of nuclear components from the analysis. Inhibition of sirtuin 1 by both pharmacological and genetic means abolished protein deacetylation and autophagy as stimulated by resveratrol, but not by piceatannol, indicating that these compounds act through distinct molecular pathways. In support of this notion, resveratrol and piceatannol synergized in inducing autophagy as well as in promoting cytoplasmic protein deacetylation. Our results highlight a cause-effect relationship between the deacetylation of cytoplasmic proteins and autophagy induction by red wine components. PMID:23070521

  17. Mutations in the Cytoplasmic Domain of the Newcastle Disease Virus Fusion Protein Confer Hyperfusogenic Phenotypes Modulating Viral Replication and Pathogenicity

    PubMed Central

    Samal, Sweety; Khattar, Sunil K.; Paldurai, Anandan; Palaniyandi, Senthilkumar; Zhu, Xiaoping; Collins, Peter L.

    2013-01-01

    The Newcastle disease virus (NDV) fusion protein (F) mediates fusion of viral and host cell membranes and is a major determinant of NDV pathogenicity. In the present study, we demonstrate the effects of functional properties of F cytoplasmic tail (CT) amino acids on virus replication and pathogenesis. Out of a series of C-terminal deletions in the CT, we were able to rescue mutant viruses lacking two or four residues (rΔ2 and rΔ4). We further rescued viral mutants with individual amino acid substitutions at each of these four terminal residues (rM553A, rK552A, rT551A, and rT550A). In addition, the NDV F CT has two conserved tyrosine residues (Y524 and Y527) and a dileucine motif (LL536-537). In other paramyxoviruses, these residues were shown to affect fusion activity and are central elements in basolateral targeting. The deletion of 2 and 4 CT amino acids and single tyrosine substitution resulted in hyperfusogenic phenotypes and increased viral replication and pathogenesis. We further found that in rY524A and rY527A viruses, disruption of the targeting signals did not reduce the expression on the apical or basolateral surface in polarized Madin-Darby canine kidney cells, whereas in double tyrosine mutant, it was reduced on both the apical and basolateral surfaces. Interestingly, in rL536A and rL537A mutants, the F protein expression was more on the apical than on the basolateral surface, and this effect was more pronounced in the rL537A mutant. We conclude that these wild-type residues in the NDV F CT have an effect on regulating F protein biological functions and thus modulating viral replication and pathogenesis. PMID:23843643

  18. Managing 'tail liability'.

    PubMed

    Frese, Richard C; Weber, Ryan J

    2013-11-01

    To reduce and control their level of tail liability, hospitals should: Utilize a self-insurance vehicle; Consider combined limits between the hospital and physicians; Communicate any program changes to the actuary, underwriter, and auditor; Continue risk management and safety practices; Ensure credit is given to the organization's own medical malpractice program. PMID:24340649

  19. REAR PROFILE OF TAIL FROM SECOND LEVEL OF TAIL DOCK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    REAR PROFILE OF TAIL FROM SECOND LEVEL OF TAIL DOCK STAND, SHOWING AIRCRAFT NUMBER (319), HORIZONTAL STABILIZER, TAIL CONE AND COOLING CTS FOR THE AUXILIARY POWER UNIT (APU), MECHANIC PAUL RIDEOUT IS LOWERING THE BALANCE PANELS ON THE STABILIZERS FOR LUBRICATION AND INSPECTION. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

  20. Detection of cytoplasmic glycosylation associated with hydroxyproline.

    PubMed

    West, Christopher M; van der Wel, Hanke; Blader, Ira J

    2006-01-01

    A special class of glycosylation occurs on a proline residue of the cytoplasmic/nuclear protein Skp1 in the social amoeba Dictyostelium. For this glycosylation to occur, the proline must first be hydroxylated by the action of a soluble prolyl 4-hydroxylase acting on the protein. Cytoplasmic prolyl 4-hydroxylases are dioxygen-dependent enzymes that have low affinity for their O2 substrate and, therefore, have been implicated in O2-sensing in Dictyostelium, as well as in vertebrates and invertebrates. The sugar-hydroxyproline linkage has low abundance, is resistant to alkali cleavage and known glycosidases, and does not bind known lectins. However, initial screens for this modification can be made by assessing changes in electrophoretic mobility of candidate proteins after treatment of cells with prolyl hydroxylase inhibitors, and/or by metabolic labeling with [3H]sugar precursors. In addition, cytoplasmic hydroxylation/glycosylation can be assessed by assaying for cytoplasmic glycosyltransferases. Here we describe these methods and examples of their use in analyzing Skp1 glycosylation in Dictyostelium and the apicomplexan Toxoplasma gondii, the causative agent of toxoplasmosis in humans. PMID:17132515

  1. CNS Myelination Requires Cytoplasmic Dynein Function

    PubMed Central

    Yang, Michele L.; Shin, Jimann; Kearns, Christina A.; Langworthy, Melissa M.; Snell, Heather; Walker, Macie B.; Appel, Bruce

    2014-01-01

    Background Cytoplasmic dynein provides the main motor force for minus-end-directed transport of cargo on microtubules. Within the vertebrate central nervous system (CNS), proliferation, neuronal migration and retrograde axon transport are among the cellular functions known to require dynein. Accordingly, mutations of DYNC1H1, which encodes the heavy chain subunit of cytoplasmic dynein, have been linked to developmental brain malformations and axonal pathologies. Oligodendrocytes, the myelinating glial cell type of the CNS, migrate from their origins to their target axons and subsequently extend multiple long processes that ensheath axons with specialized insulating membrane. These processes are filled with microtubules, which facilitate molecular transport of myelin components. However, whether oligodendrocytes require cytoplasmic dynein to ensheath axons with myelin is not known. Results We identified a mutation of zebrafish dync1h1 in a forward genetic screen that caused a deficit of oligodendrocytes. Using in vivo imaging and gene expression analyses, we additionally found evidence that dync1h1 promotes axon ensheathment and myelin gene expression. Conclusions In addition to its well known roles in axon transport and neuronal migration, cytoplasmic dynein contributes to neural development by promoting myelination. PMID:25488883

  2. An integrated model for the nucleo-cytoplasmic transport of cytoplasmic poly(A)-binding proteins.

    PubMed

    Burgess, Hannah M; Gray, Nicola K

    2012-05-01

    Cytoplasmic poly(A)-binding proteins (PABPs) regulate mRNA stability and translation. Although predominantly localized in the cytoplasm, PABP proteins also cycle through the nucleus. Recent work has established that their steady-state localization can be altered by cellular stresses such as ultraviolet (UV) radiation, and infection by several viruses, resulting in nuclear accumulation of PABPs. Here, we present further evidence that their interaction with and release from mRNA and translation complexes are important in determining their sub-cellular distribution and propose an integrated model for regulated nucleo-cytoplasmic transport of PABPs. PMID:22896784

  3. Regulation of the cytoplasmic accumulation of 5-methyltetrahydrofolate in MA104 cells is independent of folate receptor regulation.

    PubMed Central

    Kamen, B A; Johnson, C A; Wang, M T; Anderson, R G

    1989-01-01

    To better understand how the folate receptor (also known as the membrane folate binder) is able to deliver 5-methyltetrahydrofolic acid to the cytoplasm of folate-depleted MA104 cells, we have examined the kinetics of movement from the cell surface into the cytoplasm. Bound 5-methyltetrahydrofolic acid was transferred into an acid-resistant membrane compartment at the rate of 0.9-1.0 pmol/10(6) cells per h. This folate appeared in the cytoplasm at the same rate. Furthermore, cytoplasmic 5-methyltetrahydrofolic acid became polyglutamated at the rate of 0.6-0.7 pmol/10(6) cells per h. As soon as intracellular 5-methyltetrahydrofolate reached 5-7 pmol/10(6) cells, however, cytoplasmic accumulation was markedly inhibited even though the folate receptor remained functional. Therefore, the acute regulation of 5-methyltetrahydrofolic acid accumulation appears to be achieved by controlling the movement of the vitamin from the receptor into the cytoplasm of the cell. PMID:2478584

  4. Effects of dietary n-3 fatty acids and vitamin C on semen characteristics, lipid composition of sperm and blood metabolites in fat-tailed Moghani rams.

    PubMed

    Jafaroghli, M; Abdi-Benemar, H; Zamiri, M J; Khalili, B; Farshad, A; Shadparvar, A A

    2014-06-10

    Sixteen fertile rams were randomly allotted to four groups and fed either of the four diets for 14 weeks: (1) control diet (COD) without fish oil (FO) and vitamin C (VC), (2) diet containing 2.5% FO (FOD), (3) diet containing 300 mg/kg DM VC (VCD), and (4) diet containing 2.5% FO and 300 mg/kg DM VC (FCD). Semen was collected at 14-d intervals from 1 April to 10 July (out of the physiologic breeding season in Iran). Semen volume and percentages of motile and progressively motile sperm were increased by FO and VC feeding. A significant interaction was also found between FOD and VCD on motility and progressive motility percentage (P<0.05). HOS-test and percentage of sperm with normal acrosome improved significantly by FO and VC. Rams fed FCD had better HOS-test and higher proportion of sperm with normal acrosome than rams in other groups (82.4 and 93.6%, respectively). Diets containing FO and FO and VC increased the proportion of docosahexaenoic acid in sperm (P<0.05). The activity of lactate dehydrogenase in the seminal fluid was significantly affected by VC and the interaction between FO and VC (P<0.05). Blood metabolites, except glucose, were affected positively by FO. The results showed that dietary supplementation with FO and VC improved seminal quality and may have beneficial effects on fertility in Moghani rams. PMID:24745668

  5. Subcellular Partitioning of Protein Tyrosine Phosphatase 1B to the Endoplasmic Reticulum and Mitochondria Depends Sensitively on the Composition of Its Tail Anchor

    PubMed Central

    Fueller, Julia; Egorov, Mikhail V.; Walther, Kirstin A.; Sabet, Ola; Mallah, Jana; Grabenbauer, Markus; Kinkhabwala, Ali

    2015-01-01

    The canonical protein tyrosine phosphatase PTP1B is an important regulator of diverse cellular signaling networks. PTP1B has long been thought to exert its influence solely from its perch on the endoplasmic reticulum (ER); however, an additional subpopulation of PTP1B has recently been detected in mitochondria extracted from rat brain tissue. Here, we show that PTP1B’s mitochondrial localization is general (observed across diverse mammalian cell lines) and sensitively dependent on the transmembrane domain length, C-terminal charge and hydropathy of its short (≤35 amino acid) tail anchor. Our electron microscopy of specific DAB precipitation revealed that PTP1B localizes via its tail anchor to the outer mitochondrial membrane (OMM), with fluorescence lifetime imaging microscopy establishing that this OMM pool contributes to the previously reported cytoplasmic interaction of PTP1B with endocytosed epidermal growth factor receptor. We additionally examined the mechanism of PTP1B’s insertion into the ER membrane through heterologous expression of PTP1B’s tail anchor in wild-type yeast and yeast mutants of major conserved ER insertion pathways: In none of these yeast strains was ER targeting significantly impeded, providing in vivo support for the hypothesis of spontaneous membrane insertion (as previously demonstrated in vitro). Further functional elucidation of the newly recognized mitochondrial pool of PTP1B will likely be important for understanding its complex roles in cellular responses to external stimuli, cell proliferation and diseased states. PMID:26431424

  6. Interaction of T4 UvsW helicase and single-stranded DNA binding protein gp32 through its carboxy terminal acidic tail

    PubMed Central

    Perumal, Senthil K.; Nelson, Scott W.; Benkovic, Stephen J.

    2013-01-01

    Bacteriophage T4 UvsW helicase contains both unwinding and annealing activities and displays some functional similarities to bacterial RecG and RecQ helicases. UvsW is involved in several DNA repair pathways, playing important roles in recombination-dependent DNA repair and the reorganization of stalled replication forks. The T4 single-stranded DNA binding protein, gp32, is a central player in nearly all DNA replication and repair processes and is thought to facilitate their coordination by recruiting and regulating the various proteins involved. Here, we show that the activities of the UvsW protein are modulated by gp32. UvsW catalyzed unwinding of recombination intermediates such as D-loops and static X-DNA (Holliday junction mimic) to ssDNA products is enhanced by the gp32 protein. The enhancement requires the presence of the protein interaction domain of gp32 (the acidic carboxy terminus), suggesting that a specific interaction between UvsW and gp32 is required. In the absence of this interaction, the ssDNA annealing and ATP-dependent translocation activities of UvsW are severely inhibited when gp32 coats the ssDNA lattice. However, when UvsW and gp32 do interact, UvsW is able to efficiently displace the gp32 protein from the ssDNA. This ability of UvsW to remove gp32 from ssDNA may explain its ability to enhance the strand invasion activity of the T4 recombinase (UvsX) and suggests a possible new role for UvsW in gp32-mediated DNA transactions. PMID:23732982

  7. Arrest of cytoplasmic streaming induces algal proliferation in green paramecia.

    PubMed

    Takahashi, Toshiyuki; Shirai, Yohji; Kosaka, Toshikazu; Hosoya, Hiroshi

    2007-01-01

    A green ciliate Paramecium bursaria, bearing several hundreds of endosymbiotic algae, demonstrates rotational microtubule-based cytoplasmic streaming, in which cytoplasmic granules and endosymbiotic algae flow in a constant direction. However, its physiological significance is still unknown. We investigated physiological roles of cytoplasmic streaming in P. bursaria through host cell cycle using video-microscopy. Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming. Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle. Thus, cytoplasmic streaming may control the algal proliferation in P. bursaria. Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming. This is a first report to suggest that cytoplasmic streaming controls proliferation of eukaryotic cells. PMID:18159235

  8. Hybridization using cytoplasmic male sterility, cytoplasmic herbicide tolerance, and herbicide tolerance from nuclear genes

    SciTech Connect

    Beversdorf, W.D.; Erickson, L.R.; Grant, I.

    1987-04-14

    An improved process is described for producing a substantially homogeneous population of plants of a predetermined hybrid variety of crop which is capable of undergoing self-pollination and cross-pollination. The process comprises: growing in a first planting area a substantially random population of cytoplasmic male sterile plants which exhibit cytoplasmic herbicide tolerance to at least one Type A herbicide and exhibit tolerance to at least one Type B herbicide which is attributable solely to homozygous dominant nuclear genes and male fertile plants which are homozygous recessive maintainer plants for the cytoplasmic male sterile plants and which lack the cytoplasmic herbicide tolerance to at least one Type A herbicide and exhibit tolerance to at least one Type B herbicide attributable solely to the homozygous dominant nuclear genes.

  9. Processing of heparanase is mediated by syndecan-1 cytoplasmic domain and involves syntenin and α-actinin

    PubMed Central

    Shteingauz, Anna; Ilan, Neta; Vlodavsky, Israel

    2014-01-01

    Heparanase activity plays a decisive role in cell dissemination associated with cancer metastasis. Cellular uptake of heparanase is considered a pre-requisite for the delivery of latent 65 kDa heparanase to lysosomes and its subsequent proteolytic processing and activation into 8 and 50 kDa protein subunits by cathepsin L. Heparan sulfate proteoglycans, and particularly syndecan, are instrumental for heparanase uptake and activation, through a process that has been shown to occur independent of rafts. Nevertheless, the molecular mechanism underlying syndecan mediated internalization outside of rafts is unclear. Here, we examined the role of syndecan-1 cytoplasmic domain in heparanase processing, utilizing deletion constructs lacking the entire cytoplasmic domain (delta), the conserved (C1 or C2) or variable (V) regions. Heparanase processing was markedly increased following syndecan-1 over expression; In contrast, heparanase was retained at the cell membrane and its processing was impaired in cells over expressing syndecan-1 deleted for the entire cytoplasmic tail. We have next revealed that conserved domain 2 (C2) and variable (V) regions of syndecan-1 cytoplasmic tail mediate heparanase processing. Furthermore, we found that syntenin, known to interact with syndecan C2 domain, and α actinin are essential for heparanase processing. PMID:24788042

  10. Nuclear and cytoplasmic actin in dinoflagellates.

    PubMed

    Soyer-Gobillard, M O; Ausseil, J; Géraud, M L

    1996-01-01

    Experiments using monoclonal and polyclonal anti-actin antibodies allowed us to demonstrate the presence of F- or G-actin in original protists, dinoflagellates, either by biochemistry, immunofluorescence and in TEM. SDS-PAGE electrophoresis and immunoblottings made either from total or nuclear protein extracts revealed the presence of a 44-kDa band reacting with monoclonal anti-actin antibody in two species, Prorocentrum micans and Crypthecodinium cohnii, and thus demonstrated the presence of actin in nuclear and cytoplasmic fractions. After squash preparation of P micans cells, actin was identified within the nucleus and in some regions of the cytoplasm by immunofluorescence microscopy. Labelling of both the nucleolus and the centrosome region was evident together with amorphous nucleoplasmic material surrounding the chromosomes. The use of cryosections of intact P micans and C cohnii cells for immunofluorescence along with staining with DAPI to delineate the chromosomes themselves, yielded finer resolution of the intranuclear network labelling pattern and allowed us to complete our observations, in particular on the cytoplasmic labelling. In P micans, in addition to the centrosome region, the cytoplasmic channels passing through the nucleus in dividing cells are labelled. In C cohnii, the cortex, the centrosome region, the cytoplasmic channels, the region surrounding the nucleus, the filaments linking it to the cortex and the cleavage furrow are also labelled. In the nucleus of the two species, there is a prominent "weft' of fine actin filaments in the nucleoplasm forming a matrix of varying density around the persistent chromosomes. This actin matrix, of unknown function, is most conspicuous at the end of the S-phase of the cell cycle. Fluorescent derivatives of phalloidin, used as diagnostic cytochemical probes for polymeric actin (F-actin), gave similar results. Positive TEM immunolabelling of intranuclear actin confirms its presence in the nucleoplasm, in the

  11. The primary structure of rat brain (cytoplasmic) dynein heavy chain, a cytoplasmic motor enzyme.

    PubMed Central

    Zhang, Z; Tanaka, Y; Nonaka, S; Aizawa, H; Kawasaki, H; Nakata, T; Hirokawa, N

    1993-01-01

    Overlapping cDNA clones encoding the heavy chain of rat brain cytoplasmic dynein have been isolated. The isolated cDNA clones contain an open reading frame of 13,932 bp encoding 4644 aa (M(r), 532,213). The deduced protein sequence of the heavy chain of rat brain dynein shows significant similarity to sea urchin flagellar beta-dynein (27.0% identical) and to Dictyostelium cytoplasmic dynein (53.5% identical) throughout the entire sequence. The heavy chain of rat brain (cytoplasmic) dynein contains four putative nucleotide-binding consensus sequences [GX4GK(T/S)] in the central one-third region that are highly similar to those of sea urchin and Dictyostelium dyneins. The N-terminal one-third of the heavy chain of rat brain (cytoplasmic) dynein shows high similarity (43.8% identical) to that of Dictyostelium cytoplasmic dynein but poor similarity (19.4% identical) to that of sea urchin flagellar dynein. These results suggested that the C-terminal two-thirds of the dynein molecule is conserved and plays an essential role in microtubule-dependent motility activity, whereas the N-terminal regions are different between cytoplasmic and flagellar dyneins. Images Fig. 1 PMID:7690137

  12. The tail plane

    NASA Technical Reports Server (NTRS)

    Munk, Max M

    1923-01-01

    This report deals with the calculation of the equilibrium, statistical stability, and damping of the tail plane. The author has simplified the present theory of longitudinal stability for the particular purpose of obtaining one definite coefficient characteristics of the effect of the tail plane. This coefficient is obtained by substituting certain aerodynamic characteristics and some dimensions of the airplane in a comparatively simple mathematical expression. Care has been taken to confine all aerodynamical information necessary for the calculation of the coefficient to the well-known curves representing the qualities of the wing section. This is done by making use of the present results of modern aerodynamics. All formulas and relations necessary for the calculation are contained in the paper. They give in some cases only an approximation of the real values. An example of calculation is added in order to illustrate the application of the method. The coefficient indicates not only whether the effect of the tail plane is great enough, but also whether it is not too great. It appears that the designer has to avoid a certain critical length of the fuselage, which inevitably gives rise to periodical oscillations of the airplane. The discussion also shows the way and in what direction to carry out experimental work.

  13. Modelling Cometary Sodium Tails

    NASA Astrophysics Data System (ADS)

    Birkett, K. S.; Jones, G. H.; Coates, A. J.

    2013-12-01

    Neutral sodium is readily observed in cometary spectra and can be seen to form its own distinct tail at high activity comets. Solar radiation pressure accelerates the sodium atoms antisunward and, as strong sodium absorption lines are present in the solar spectrum, the magnitude of this force is dependent upon the Doppler shift of the incident solar radiation. Therefore the heliocentric velocity of the sodium atom directly determines its acceleration. This can produce unique effects, such as a stagnation region. Sodium is relatively easy to detect and so can potentially be used to trace mechanisms in the coma that are otherwise difficult to observe. The source of neutral sodium in the tail currently remains unknown. We have therefore developed a new, three dimensional Monte-Carlo model of neutral cometary sodium in order to facilitate testing of different source production functions. It includes weightings due to neutral sodium lifetime, variation of cometary sodium emission due to Fraunhofer absorption lines and solar flux variation with heliocentric distance. The Swings and Greenstein effects, which can have particularly dramatic effects in near-Sun comets, are also considered comprehensively. Preliminary results from this model are presented, focusing on a comparison of predictions of the neutral sodium tail of Comet C/2012 S1 (ISON) with initial observations.

  14. Forming a tough shell via an intracellular matrix and cellular junctions in the tail epidermis of Oikopleura dioica (Chordata: Tunicata: Appendicularia)

    NASA Astrophysics Data System (ADS)

    Nakashima, Keisuke; Nishino, Atsuo; Hirose, Euichi

    2011-08-01

    A postanal tail is a major synapomorphy of the phylum Chordata, which is composed of three subphyla: Vertebrata, Cephalochordata, and Tunicata (Urochordata). Among tunicates, appendicularians are the only group that retains the tail in the adult, and the adult tail functions in locomotion and feeding in combination with a cellulose-based house structure. Given the phylogenetic position of tunicates, the appendicularian adult tail may possess ancestral features of the chordate tail. We assess the ultrastructural development of the tail epidermis of the appendicularian Oikopleura dioica. The epidermis of the larval tail is enclosed by the larval envelope, which is a thin sheet similar to the outer tunic layer of ascidian larvae. The epidermis of the adult tail seems to bear no tunic-like cellulosic integuments, and the tail fin is a simple folding of the epidermis. Every epidermal cell, except for the triangular cells at the edge of the tail fin, has a conspicuous matrix layer of fibrous content in the apical cytoplasm without enclosing membranes. The epidermis of the larval tail does not have a fibrous matrix layer, suggesting the production of the layer during larval development and metamorphosis. Zonulae adhaerentes firmly bind the epidermal cells of the adult tail to one another, and the dense microfilaments lining the cell borders constitute a mechanical support for the cell membranes. The intracellular matrix, cell junctions, and cytoskeletons probably make the tail epidermis a tough, flexible shell supporting the active beating of the oikopleuran adult tail.

  15. Mechanism of Cytoplasmic mRNA Translation

    PubMed Central

    2015-01-01

    Protein synthesis is a fundamental process in gene expression that depends upon the abundance and accessibility of the mRNA transcript as well as the activity of many protein and RNA-protein complexes. Here we focus on the intricate mechanics of mRNA translation in the cytoplasm of higher plants. This chapter includes an inventory of the plant translational apparatus and a detailed review of the translational processes of initiation, elongation, and termination. The majority of mechanistic studies of cytoplasmic translation have been carried out in yeast and mammalian systems. The factors and mechanisms of translation are for the most part conserved across eukaryotes; however, some distinctions are known to exist in plants. A comprehensive understanding of the complex translational apparatus and its regulation in plants is warranted, as the modulation of protein production is critical to development, environmental plasticity and biomass yield in diverse ecosystems and agricultural settings. PMID:26019692

  16. Protein diffusion in mammalian cell cytoplasm.

    PubMed

    Kühn, Thomas; Ihalainen, Teemu O; Hyväluoma, Jari; Dross, Nicolas; Willman, Sami F; Langowski, Jörg; Vihinen-Ranta, Maija; Timonen, Jussi

    2011-01-01

    We introduce a new method for mesoscopic modeling of protein diffusion in an entire cell. This method is based on the construction of a three-dimensional digital model cell from confocal microscopy data. The model cell is segmented into the cytoplasm, nucleus, plasma membrane, and nuclear envelope, in which environment protein motion is modeled by fully numerical mesoscopic methods. Finer cellular structures that cannot be resolved with the imaging technique, which significantly affect protein motion, are accounted for in this method by assigning an effective, position-dependent porosity to the cell. This porosity can also be determined by confocal microscopy using the equilibrium distribution of a non-binding fluorescent protein. Distinction can now be made within this method between diffusion in the liquid phase of the cell (cytosol/nucleosol) and the cytoplasm/nucleoplasm. Here we applied the method to analyze fluorescence recovery after photobleach (FRAP) experiments in which the diffusion coefficient of a freely-diffusing model protein was determined for two different cell lines, and to explain the clear difference typically observed between conventional FRAP results and those of fluorescence correlation spectroscopy (FCS). A large difference was found in the FRAP experiments between diffusion in the cytoplasm/nucleoplasm and in the cytosol/nucleosol, for all of which the diffusion coefficients were determined. The cytosol results were found to be in very good agreement with those by FCS. PMID:21886771

  17. Speciation And Colloid Transport of Arsenic From Mine Tailings

    SciTech Connect

    Slowey, A.J.; Johnson, S.B.; Newville, M.; Brown, G.E., Jr.

    2007-07-13

    In addition to affecting biogeochemical transformations, the speciation of As also influences its transport from tailings at inoperative mines. The speciation of As in tailings from the Sulfur Bank Mercury Mine site in Clear Lake, California (USA) (a hot-spring Hg deposit) and particles mobilized from these tailings have been examined during laboratory-column experiments. Solutions containing two common, plant-derived organic acids (oxalic and citric acid) were pumped at 13 pore volumes d{sup -1} through 25 by 500 mm columns of calcined Hg ore, analogous to the pedogenesis of tailings. Chemical analysis of column effluent indicated that all of the As mobilized was particulate (1.5 mg, or 6% of the total As in the column through 255 pore volumes of leaching). Arsenic speciation was evaluated using X-ray absorption spectroscopy (XAS), indicating the dominance of arsenate [As(V)] sorbed to poorly crystalline Fe(III)-(hydr)oxides and coprecipitated with jarosite [KFe{sub 3}(SO{sub 4}, AsO{sub 4}){sub 2}(OH){sub 6}] with no detectable primary or secondary minerals in the tailings and mobilized particles. Sequential chemical extractions (SCE) of <45 {micro}m mine tailings fractions also suggest that As occurs adsorbed to Fe (hydr)oxides (35%) and coprecipitated within poorly crystalline phases (45%). In addition, SCEs suggest that As is associated with 1 N acid-soluble phases such as carbonate minerals (20%) and within crystalline Fe-(hydr)oxides (10%). The finding that As is transported from these mine tailings dominantly as As(V) adsorbed to Fe (hydr)oxides or coprecipitated within hydroxysulfates such as jarosite suggests that As release from soils and sediments contaminated with tailings will be controlled by either organic acid-promoted dissolution or reductive dissolution of host phases.

  18. Maturation-Dependent Human Immunodeficiency Virus Type 1 Particle Fusion Requires a Carboxyl-Terminal Region of the gp41 Cytoplasmic Tail▿

    PubMed Central

    Jiang, Jiyang; Aiken, Christopher

    2007-01-01

    Lentiviruses, including human immunodeficiency virus type 1 (HIV-1), typically encode fusion glycoproteins with long cytoplasmic tails (CTs). We previously reported that immature HIV-1 particles are inhibited for fusion with target cells by a mechanism requiring the 152-amino-acid CT of gp41. The gp41 CT was also shown to mediate the detergent-resistant association of the HIV-1 envelope glycoprotein complex with immature HIV-1 particles, indicating that the gp41 CT forms a stable complex with Gag in immature virions. In the present study, we analyzed the effects of progressive truncations and point mutations in the gp41 CT on the fusion of mature and immature HIV-1 particles with target cells. We also determined the effects of these mutations on the detergent-resistant association of gp41 with immature HIV-1 particles. Removal of the C-terminal 28 amino acids relieved the dependence of HIV-1 fusion on maturation. However, a mutant Env protein lacking this region remained associated with immature HIV-1 particles treated with nonionic detergent. Further mutational analysis of the C-terminal region of gp41 revealed two specific sequences required for maturation-dependent HIV-1 fusion. Collectively, our results demonstrate that the extreme C terminus of gp41 plays a key role in coupling HIV-1 fusion competence to virion maturation. They further indicate that the stable association of gp41 with Gag in immature virions is not sufficient for inhibition of immature HIV-1 particle fusion. PMID:17609279

  19. Evidence that the production of acetate in rat hepatocytes is a predominantly cytoplasmic process.

    PubMed Central

    Crabtree, B; Souter, M J; Anderson, S E

    1989-01-01

    By using [1-14C]butyrate, the fluxes of butyrate to acetate and fatty acids were measured in rat hepatocytes. Both fluxes were inhibited to a similar extent by (-)-hydroxycitrate, with no significant effect on butyrate uptake. These results indicate that acetate formation takes place in the cytoplasm, presumably via ATP-stimulated acetyl-CoA hydrolase. Since acetate formation occurred despite a net uptake of acetate, the results are also consistent with the operation of a substrate cycle between acetate and acetyl-CoA, recently proposed by other workers, and suggest that this cycle is cytoplasmic. PMID:2564776

  20. Floods from tailings dam failures.

    PubMed

    Rico, M; Benito, G; Díez-Herrero, A

    2008-06-15

    This paper compiles the available information on historic tailings dam failures with the purpose to establish simple correlations between tailings ponds geometric parameters (e.g., dam height, tailings volume) and the hydraulic characteristics of floods resulting from released tailings. Following the collapse of a mining waste dam, only a part of tailings and polluted water stored at the dam is released, and this outflow volume is difficult to estimate prior the incident. In this study, tailings' volume stored at the time of failure was shown to have a good correlation (r2=0.86) with the tailings outflow volume, and the volume of spilled tailings was correlated with its run-out distance (r2=0.57). An envelope curve was drawn encompassing the majority of data points indicating the potential maximum downstream distance affected by a tailings' spill. The application of the described regression equations for prediction purposes needs to be treated with caution and with support of on-site measurement and observations. However, they may provide a universal baseline approximation on tailing outflow characteristics (even if detailed dam information is unavailable), which is of a great importance for risk analysis purposes. PMID:18096316

  1. The geomagnetic tail

    SciTech Connect

    Birn, J. )

    1991-01-01

    A review is presented of the plasma sheet and lobe regions of the magnetotail, focusing principally on large-scale processes or microprocesses with some large-scale effects. Consideration is given to quiet and average structures, not necessarily related to activity phases, with quasi-steady convection aspects, and with the characteristics of dynamic phases including acceleration mechanisms and single particle aspects. Attention is given to various activity models, average and quiet time properties, properties and effects of magnetospheric convection, dynamics of the magnetotail, and the near tail, substorm current wedge.

  2. Functional Architecture of the Cytoplasmic Entrance to the Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel Pore.

    PubMed

    El Hiani, Yassine; Linsdell, Paul

    2015-06-19

    As an ion channel, the cystic fibrosis transmembrane conductance regulator must form a continuous pathway for the movement of Cl(-) and other anions between the cytoplasm and the extracellular solution. Both the structure and the function of the membrane-spanning part of this pathway are well defined. In contrast, the structure of the pathway that connects the cytoplasm to the membrane-spanning regions is unknown, and functional roles for different parts of the protein forming this pathway have not been described. We used patch clamp recording and substituted cysteine accessibility mutagenesis to identify positively charged amino acid side chains that attract cytoplasmic Cl(-) ions to the inner mouth of the pore. Our results indicate that the side chains of Lys-190, Arg-248, Arg-303, Lys-370, Lys-1041, and Arg-1048, located in different intracellular loops of the protein, play important roles in the electrostatic attraction of Cl(-) ions. Mutation and covalent modification of these residues have charge-dependent effects on the rate of Cl(-) permeation, demonstrating their functional role in maximization of Cl(-) flux. Other nearby positively charged side chains were not involved in electrostatic interactions with Cl(-). The location of these Cl(-)-attractive residues suggests that cytoplasmic Cl(-) ions enter the pore via a lateral portal located between the cytoplasmic extensions to the fourth and sixth transmembrane helices; a secondary, functionally less relevant portal might exist between the extensions to the 10th and 12th transmembrane helices. These results define the cytoplasmic mouth of the pore and show how it attracts Cl(-) ions from the cytoplasm. PMID:25944907

  3. Functional Architecture of the Cytoplasmic Entrance to the Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel Pore*

    PubMed Central

    El Hiani, Yassine; Linsdell, Paul

    2015-01-01

    As an ion channel, the cystic fibrosis transmembrane conductance regulator must form a continuous pathway for the movement of Cl− and other anions between the cytoplasm and the extracellular solution. Both the structure and the function of the membrane-spanning part of this pathway are well defined. In contrast, the structure of the pathway that connects the cytoplasm to the membrane-spanning regions is unknown, and functional roles for different parts of the protein forming this pathway have not been described. We used patch clamp recording and substituted cysteine accessibility mutagenesis to identify positively charged amino acid side chains that attract cytoplasmic Cl− ions to the inner mouth of the pore. Our results indicate that the side chains of Lys-190, Arg-248, Arg-303, Lys-370, Lys-1041, and Arg-1048, located in different intracellular loops of the protein, play important roles in the electrostatic attraction of Cl− ions. Mutation and covalent modification of these residues have charge-dependent effects on the rate of Cl− permeation, demonstrating their functional role in maximization of Cl− flux. Other nearby positively charged side chains were not involved in electrostatic interactions with Cl−. The location of these Cl−-attractive residues suggests that cytoplasmic Cl− ions enter the pore via a lateral portal located between the cytoplasmic extensions to the fourth and sixth transmembrane helices; a secondary, functionally less relevant portal might exist between the extensions to the 10th and 12th transmembrane helices. These results define the cytoplasmic mouth of the pore and show how it attracts Cl− ions from the cytoplasm. PMID:25944907

  4. Connexin channel permeability to cytoplasmic molecules.

    PubMed

    Harris, Andrew L

    2007-01-01

    Connexin channels are known to be permeable to a variety of cytoplasmic molecules. The first observation of second messenger junctional permeability, made approximately 30 years ago, sparked broad interest in gap junction channels as mediators of intercellular molecular signaling. Since then, much has been learned about the diversity of connexin channels with regard to isoform diversity, tissue and developmental distribution, modes of channel regulation, assembly, expression, biochemical modification and permeability, all of which appear to be dynamically regulated. This information has expanded the potential roles of connexin channels in development, physiology and disease, and made their elucidation much more complex--30 years ago such an orchestra of junctional dynamics was unanticipated. Only recently, however, have investigators been able to directly address, in this more complex framework, the key issue: what specific biological molecules, second messengers and others, are able to permeate the various types of connexin channels, and how well? An important related issue, given the ever-growing list of connexin-related pathologies, is how these permeabilities are altered by disease-causing connexin mutations. Together, many studies show that a variety of cytoplasmic molecules can permeate the different types of connexin channels. A few studies reveal differences in permeation by different molecules through a particular type of connexin channel, and differences in permeation by a particular molecule through different types of connexin channels. This article describes and evaluates the various methods used to obtain these data, presents an annotated compilation of the results, and discusses the findings in the context of what can be inferred about mechanism of selectivity and potential relevance to signaling. The data strongly suggest that highly specific interactions take place between connexin pores and specific biological molecular permeants, and that those

  5. Uranium mill tailings and radon

    SciTech Connect

    Hanchey, L A

    1981-04-01

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the United States may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

  6. Uranium mill tailings and radon

    SciTech Connect

    Hanchey, L A

    1981-01-01

    The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

  7. Cytoplasmic calcium levels in protoplasts from the cap and elongation zone of maize roots

    NASA Technical Reports Server (NTRS)

    Kiss, H. G.; Evans, M. L.; Johnson, J. D.

    1991-01-01

    Calcium has been implicated as a key component in the signal transduction process of root gravitropism. We measured cytoplasmic free calcium in protoplasts isolated from the elongation zone and cap of primary roots of light-grown, vertically oriented seedlings of Zea mays L. Protoplasts were loaded with the penta-potassium salts of fura-2 and indo-1 by incubation in acidic solutions of these calcium indicators. Loading increased with decreasing pH but the pH dependence was stronger for indo-1 than for fura-2. In the case of fura-2, loading was enhanced only at the lowest pH (4.5) tested. Dyes loaded in this manner were distributed predominantly in the cytoplasm as indicated by fluorescence patterns. As an alternative method of loading, protoplasts were incubated with the acetoxymethylesters of fura-2 and indo-1. Protoplasts loaded by this method exhibited fluorescence both in the cytoplasm and in association with various organelles. Cytoplasmic calcium levels measured using spectrofluorometry, were found to be 160 +/- 40 nM and 257 +/- 27 nM, respectively, in populations of protoplasts from the root cap and elongation zone. Cytoplasmic free calcium did not increase upon addition of calcium to the incubation medium, indicating that the passive permeability to calcium was low.

  8. Chemical ligation of the influenza M2 protein for solid-state NMR characterization of the cytoplasmic domain.

    PubMed

    Kwon, Byungsu; Tietze, Daniel; White, Paul B; Liao, Shu Y; Hong, Mei

    2015-07-01

    Solid-state NMR-based structure determination of membrane proteins and large protein complexes faces the challenge of limited spectral resolution when the proteins are uniformly (13)C-labeled. A strategy to meet this challenge is chemical ligation combined with site-specific or segmental labeling. While chemical ligation has been adopted in NMR studies of water-soluble proteins, it has not been demonstrated for membrane proteins. Here we show chemical ligation of the influenza M2 protein, which contains a transmembrane (TM) domain and two extra-membrane domains. The cytoplasmic domain, which contains an amphipathic helix (AH) and a cytoplasmic tail, is important for regulating virus assembly, virus budding, and the proton channel activity. A recent study of uniformly (13)C-labeled full-length M2 by spectral simulation suggested that the cytoplasmic tail is unstructured. To further test this hypothesis, we conducted native chemical ligation of the TM segment and part of the cytoplasmic domain. Solid-phase peptide synthesis of the two segments allowed several residues to be labeled in each segment. The post-AH cytoplasmic residues exhibit random-coil chemical shifts, low bond order parameters, and a surface-bound location, thus indicating that this domain is a dynamic random coil on the membrane surface. Interestingly, the protein spectra are similar between a model membrane and a virus-mimetic membrane, indicating that the structure and dynamics of the post-AH segment is insensitive to the lipid composition. This chemical ligation approach is generally applicable to medium-sized membrane proteins to provide site-specific structural constraints, which complement the information obtained from uniformly (13)C, (15)N-labeled proteins. PMID:25966817

  9. Chemical ligation of the influenza M2 protein for solid-state NMR characterization of the cytoplasmic domain

    PubMed Central

    Kwon, Byungsu; Tietze, Daniel; White, Paul B; Liao, Shu Y; Hong, Mei

    2015-01-01

    Solid-state NMR-based structure determination of membrane proteins and large protein complexes faces the challenge of limited spectral resolution when the proteins are uniformly 13C-labeled. A strategy to meet this challenge is chemical ligation combined with site-specific or segmental labeling. While chemical ligation has been adopted in NMR studies of water-soluble proteins, it has not been demonstrated for membrane proteins. Here we show chemical ligation of the influenza M2 protein, which contains a transmembrane (TM) domain and two extra-membrane domains. The cytoplasmic domain, which contains an amphipathic helix (AH) and a cytoplasmic tail, is important for regulating virus assembly, virus budding, and the proton channel activity. A recent study of uniformly 13C-labeled full-length M2 by spectral simulation suggested that the cytoplasmic tail is unstructured. To further test this hypothesis, we conducted native chemical ligation of the TM segment and part of the cytoplasmic domain. Solid-phase peptide synthesis of the two segments allowed several residues to be labeled in each segment. The post-AH cytoplasmic residues exhibit random-coil chemical shifts, low bond order parameters, and a surface-bound location, thus indicating that this domain is a dynamic random coil on the membrane surface. Interestingly, the protein spectra are similar between a model membrane and a virus-mimetic membrane, indicating that the structure and dynamics of the post-AH segment is insensitive to the lipid composition. This chemical ligation approach is generally applicable to medium-sized membrane proteins to provide site-specific structural constraints, which complement the information obtained from uniformly 13C, 15N-labeled proteins. PMID:25966817

  10. 3. VIEW OF WEST TAILING DAM, LARGE TANK, AND TAILING, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW OF WEST TAILING DAM, LARGE TANK, AND TAILING, LOOKING NORTHEAST. A SIX-FOOT SCALE IS LOCATED AGAINST WALL ON LEFT. PURPOSE OF TANK IS UNKNOWN, BUT APPEARS TO HAVE FALLEN FROM ITS ORIGINAL LOCATION AT THE MILL SITE, UP AND TO THE RIGHT OF THIS VIEW. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

  11. PTEN functions by recruitment to cytoplasmic vesicles.

    PubMed

    Naguib, Adam; Bencze, Gyula; Cho, Hyejin; Zheng, Wu; Tocilj, Ante; Elkayam, Elad; Faehnle, Christopher R; Jaber, Nadia; Pratt, Christopher P; Chen, Muhan; Zong, Wei-Xing; Marks, Michael S; Joshua-Tor, Leemor; Pappin, Darryl J; Trotman, Lloyd C

    2015-04-16

    PTEN is proposed to function at the plasma membrane, where receptor tyrosine kinases are activated. However, the majority of PTEN is located throughout the cytoplasm. Here, we show that cytoplasmic PTEN is distributed along microtubules, tethered to vesicles via phosphatidylinositol 3-phosphate (PI(3)P), the signature lipid of endosomes. We demonstrate that the non-catalytic C2 domain of PTEN specifically binds PI(3)P through the CBR3 loop. Mutations render this loop incapable of PI(3)P binding and abrogate PTEN-mediated inhibition of PI 3-kinase/AKT signaling. This loss of function is rescued by fusion of the loop mutant PTEN to FYVE, the canonical PI(3)P binding domain, demonstrating the functional importance of targeting PTEN to endosomal membranes. Beyond revealing an upstream activation mechanism of PTEN, our data introduce the concept of PI 3-kinase signal activation on the vast plasma membrane that is contrasted by PTEN-mediated signal termination on the small, discrete surfaces of internalized vesicles. PMID:25866245

  12. Characterization of the MUC1-C Cytoplasmic Domain as a Cancer Target

    PubMed Central

    Raina, Deepak; Agarwal, Praveen; Lee, James; Bharti, Ajit; McKnight, C. James; Sharma, Pankaj; Kharbanda, Surender; Kufe, Donald

    2015-01-01

    Mucin 1 (MUC1) is a heterodimeric protein that is aberrantly expressed in diverse human carcinomas and certain hematologic malignancies. The oncogenic MUC1 transmembrane C-terminal subunit (MUC1-C) functions in part by transducing growth and survival signals from cell surface receptors. However, little is known about the structure of the MUC1-C cytoplasmic domain as a potential drug target. Using methods for structural predictions, our results indicate that a highly conserved CQCRRK sequence, which is adjacent to the cell membrane, forms a small pocket that exposes the two cysteine residues for forming disulfide bonds. By contrast, the remainder of the MUC1-C cytoplasmic domain has no apparent structure, consistent with an intrinsically disordered protein. Our studies thus focused on targeting the MUC1 CQCRRK region. The results show that L- and D-amino acid CQCRRK-containing peptides bind directly to the CQC motif. We further show that the D-amino acid peptide, designated GO-203, blocks homodimerization of the MUC1-C cytoplasmic domain in vitro and in transfected cells. Moreover, GO-203 binds directly to endogenous MUC1-C in breast and lung cancer cells. Colocalization studies further demonstrate that GO-203 predominantly binds to MUC1-C at the cell membrane. These findings support the further development of agents that target the MUC1-C cytoplasmic domain CQC motif and thereby MUC1-C function in cancer cells. PMID:26267657

  13. Mechanisms of cytoplasmic pH regulation in alkaliphilic strains of Bacillus.

    PubMed

    Krulwich, T A; Ito, M; Gilmour, R; Guffanti, A A

    1997-11-01

    The central challenge for extremely alkaliphilic Bacillus species is the need to establish and sustain a cytoplasmic pH that is over two units lower than the highly alkaline medium. Its centrality is suggested by the strong correlation between the growth rate in the upper range of pH for growth, i.e., at values above pH 10.5, and the cytoplasmic pH. The diminishing growth rate at extremely high pH values correlates better with the rise in cytoplasmic pH than with other energetic parameters. There are also general adaptations of alkaliphiles that are crucial prerequisites for pH homeostasis as well as other cell functions, i.e., the reduced basic amino acid content of proteins or segments thereof that are exposed to the medium, and there are other challenges of alkaliphily that emerge from solution of the cytoplasmic pH problem, i.e., reduction of the chemiosmotic driving force. For cells growing on glucose, strong evidence exists for the importance of acidic cell wall components, teichuronic acid and teichuronopeptides, in alkaliphily. These wall macromolecules may provide a passive barrier to ion flux. For cells growing on fermentable carbon sources, this and other passive mechanisms may have a particularly substantial role, but for cells growing on both fermentable and nonfermentable substrates, an active Na+-dependent cycle is apparently required for alkaliphily and the alkaliphile's remarkable capacity for pH homeostasis. The active cycle involves primary establishment of an electrochemical gradient via proton extrusion, a secondary electrogenic Na+/H+ antiport to achieve net acidification of the cytoplasm relative to the outside pH, and mechanisms for Na+ re-entry. Recent work in several laboratories on the critical antiporters involved in this cycle has begun to clarify the number and characteristics of the porters that support active mechanisms of pH homeostasis. PMID:9680297

  14. Telling tails: selective pressures acting on investment in lizard tails.

    PubMed

    Fleming, Patricia A; Valentine, Leonie E; Bateman, Philip W

    2013-01-01

    Caudal autotomy is a common defense mechanism in lizards, where the animal may lose part or all of its tail to escape entrapment. Lizards show an immense variety in the degree of investment in a tail (i.e., length) across species, with tails of some species up to three or four times body length (snout-vent length [SVL]). Additionally, body size and form also vary dramatically, including variation in leg development and robustness and length of the body and tail. Autotomy is therefore likely to have fundamentally different effects on the overall body form and function in different species, which may be reflected directly in the incidence of lost/regenerating tails within populations or, over a longer period, in terms of relative tail length for different species. We recorded data (literature, museum specimens, field data) for relative tail length (n=350 species) and the incidence of lost/regenerating tails (n=246 species). We compared these (taking phylogeny into account) with intrinsic factors that have been proposed to influence selective pressures acting on caudal autotomy, including body form (robustness, body length, leg development, and tail specialization) and ecology (foraging behavior, physical and temporal niches), in an attempt to identify patterns that might reflect adaptive responses to these different factors. More gracile species have relatively longer tails (all 350 spp., P < 0.001; also significant for five of the six families tested separately), as do longer (all species, P < 0.001; Iguanidae, P < 0.05; Lacertidae, P < 0.001; Scindidae, P < 0.001), climbing (all species, P < 0.05), and diurnal (all species, P < 0.01; Pygopodidae, P < 0.01) species; geckos without specialized tails (P < 0.05); or active-foraging skinks (P < 0.05). We also found some relationships with the data for caudal autotomy, with more lost/regenerating tails for nocturnal lizards (all 246 spp., P < 0.01; Scindidae, P < 0.05), larger skinks (P < 0.05), climbing geckos (P < 0

  15. Runaway tails in magnetized plasmas

    NASA Technical Reports Server (NTRS)

    Moghaddam-Taaheri, E.; Vlahos, L.; Rowland, H. L.; Papadopoulos, K.

    1985-01-01

    The evolution of a runaway tail driven by a dc electric field in a magnetized plasma is analyzed. Depending on the strength of the electric field and the ratio of plasma to gyrofrequency, there are three different regimes in the evolution of the tail. The tail can be (1) stable with electrons accelerated to large parallel velocities, (2) unstable to Cerenkov resonance because of the depletion of the bulk and the formation of a positive slope, (3) unstable to the anomalous Doppler resonance instability driven by the large velocity anisotropy in the tail. Once an instability is triggered (Cerenkov or anomalous Doppler resonance) the tail relaxes into an isotropic distribution. The role of a convection type loss term is also discussed.

  16. A 127-kDa protein (UV-DDB) binds to the cytoplasmic domain of the Alzheimer's amyloid precursor protein.

    PubMed

    Watanabe, T; Sukegawa, J; Sukegawa, I; Tomita, S; Iijima, K; Oguchi, S; Suzuki, T; Nairn, A C; Greengard, P

    1999-02-01

    Alzheimer amyloid precursor protein (APP) is an integral membrane protein with a short cytoplasmic domain of 47 amino acids. It is hoped that identification of proteins that interact with the cytoplasmic domain will provide new insights into the physiological function of APP and, in turn, into the pathogenesis of Alzheimer's disease. To identify proteins that interact with the cytoplasmic domain of APP, we employed affinity chromatography using an immobilized synthetic peptide corresponding to residues 645-694 of APP695 and identified a protein of approximately 130 kDa in rat brain cytosol. Amino acid sequencing of the protein revealed the protein to be a rat homologue of monkey UV-DDB (UV-damaged DNA-binding protein, calculated molecular mass of 127 kDa). UV-DDB/p127 co-immunoprecipitated with APP using an anti-APP antibody from PC12 cell lysates. APP also co-immunoprecipitated with UV-DDB/p127 using an anti-UV-DDB/p127 antibody. These results indicate that UV-DDB/p127, which is present in the cytosolic fraction, forms a complex with APP through its cytoplasmic domain. In vitro binding experiments using a glutathione S-transferase-APP cytoplasmic domain fusion protein and several mutants indicated that the YENPTY motif within the APP cytoplasmic domain, which is important in the internalization of APP and amyloid beta protein secretion, may be involved in the interaction between UV-DDB/p127 and APP. PMID:9930726

  17. Loss of desmoplakin tail causes lethal acantholytic epidermolysis bullosa.

    PubMed

    Jonkman, Marcel F; Pasmooij, Anna M G; Pasmans, Suzanne G M A; van den Berg, Maarten P; Ter Horst, Henk J; Timmer, Albertus; Pas, Hendri H

    2005-10-01

    The cytoplasmic plaque protein desmoplakin (DP), which is located in desmosomes, plays a major role in epithelial and muscle cell adhesion by linking the transmembrane cadherins to the cytoplasmic intermediate filament network. Mutations of DP may cause striate palmoplantar keratoderma, arrhythmogenic right ventricular dysplasia, skin fragility/woolly hair syndrome, Naxos-like disease, and Carvajal syndrome. DP must be indispensable, because DP-/- mice are early abortive. Here, we report a patient with severe fragility of skin and mucous membranes caused by genetic truncation of the DP tail. The new phenotype is lethal in the neonatal period because of immense transcutaneous fluid loss. The phenotype also comprised universal alopecia, neonatal teeth, and nail loss. Histology showed suprabasal clefting and acantholysis throughout the spinous layer, mimicking pemphigus. Electron microscopy revealed disconnection of keratin intermediate filaments from desmosomes. Immunofluorescence staining of DP showed a distinct punctate intercellular pattern in the patient's skin. Protein analysis revealed expression of truncated DP polypeptides. Mutational analysis of the patient demonstrated compound heterozygosity for two DP mutations, 6079C-->T (R1934X) and 6370delTT, respectively. Aberrant mRNA transcripts that predict premature termination of translation with loss of the three intermediate filament-binding subdomains in the DP tail were detected by RT-PCR. The new dramatic phenotype, which we named "lethal acantholytic epidermolysis bullosa," underscores the paramount role of DP in epidermal integrity. PMID:16175511

  18. RINGO/cdk1 and CPEB mediate poly(A) tail stabilization and translational regulation by ePAB

    PubMed Central

    Kim, Jong Heon; Richter, Joel D.

    2007-01-01

    One activity that controls mRNA translation in vertebrate oocytes, embryos, and neurons is cytoplasmic polyadenylation. In Xenopus oocytes, where much of the biochemistry of this process has been elucidated, nuclear pre-mRNAs containing a cytoplasmic polyadenylation element (CPE) in their 3′ untranslated regions (UTRs) have long poly(A) tails; once the RNAs are spliced and transported to the cytoplasm, the tails are shortened. Following the resumption of meiosis, the poly(A) tails are lengthened and translation ensues. CPEB is a sequence-specific RNA-binding protein that coordinates these events and does so by binding to the CPE as well as several factors including Gld2, a poly(A) polymerase, and PARN [poly(A)-specific ribonuclease], a deadenylase. Here, we show that ePAB, embryonic poly(A)-binding protein, transiently associates with the polyadenylation complex; it initially interacts with CPEB, but after polyadenylation, it binds the poly(A) tail. ePAB dissociation from CPEB is regulated by RINGO (Rapid Inducer of G2/M progression in Oocytes), a cyclin B1-like cofactor that activates cdk1, a protein kinase that phosphorylates CPEB. Subsequent ePAB binding to the poly(A) tail is necessary to protect the homopolymer from degradation by deadenylating enzymes. Poly(A)-bound ePAB also interacts with eIF4G, which instigates translation initiation of CPEB-bound mRNAs. PMID:17938241

  19. Non-ideal solution thermodynamics of cytoplasm.

    PubMed

    Ross-Rodriguez, Lisa U; Elliott, Janet A W; McGann, Locksley E

    2012-10-01

    Quantitative description of the non-ideal solution thermodynamics of the cytoplasm of a living mammalian cell is critically necessary in mathematical modeling of cryobiology and desiccation and other fields where the passive osmotic response of a cell plays a role. In the solution thermodynamics osmotic virial equation, the quadratic correction to the linear ideal, dilute solution theory is described by the second osmotic virial coefficient. Herein we report, for the first time, intracellular solution second osmotic virial coefficients for four cell types [TF-1 hematopoietic stem cells, human umbilical vein endothelial cells (HUVEC), porcine hepatocytes, and porcine chondrocytes] and further report second osmotic virial coefficients indistinguishable from zero (for the concentration range studied) for human hepatocytes and mouse oocytes. PMID:23840923

  20. Physical properties of cytoplasmic intermediate filaments.

    PubMed

    Block, Johanna; Schroeder, Viktor; Pawelzyk, Paul; Willenbacher, Norbert; Köster, Sarah

    2015-11-01

    Intermediate filaments (IFs) constitute a sophisticated filament system in the cytoplasm of eukaryotes. They form bundles and networks with adapted viscoelastic properties and are strongly interconnected with the other filament types, microfilaments and microtubules. IFs are cell type specific and apart from biochemical functions, they act as mechanical entities to provide stability and resilience to cells and tissues. We review the physical properties of these abundant structural proteins including both in vitro studies and cell experiments. IFs are hierarchical structures and their physical properties seem to a large part be encoded in the very specific architecture of the biopolymers. Thus, we begin our review by presenting the assembly mechanism, followed by the mechanical properties of individual filaments, network and structure formation due to electrostatic interactions, and eventually the mechanics of in vitro and cellular networks. This article is part of a Special Issue entitled: Mechanobiology. PMID:25975455

  1. Quantifying intermittent transport in cell cytoplasm

    NASA Astrophysics Data System (ADS)

    Lagache, Thibault; Holcman, David

    2008-03-01

    Active cellular transport is a fundamental mechanism for protein and vesicle delivery, cell cycle, and molecular degradation. Viruses can hijack the transport system and use it to reach the nucleus. Most transport processes consist of intermittent dynamics, where the motion of a particle, such as a virus, alternates between pure Brownian and directed movement along microtubules. In this Rapid Communication, we estimate the mean time for a particle to attach to a microtubule network. This computation leads to a coarse grained equation of the intermittent motion in radial and cylindrical geometries. Finally, by using the degradation activity inside the cytoplasm, we obtain refined asymptotic estimations for the probability and the mean time a virus reaches a small nuclear pore.

  2. Quantifying intermittent transport in cell cytoplasm.

    PubMed

    Lagache, Thibault; Holcman, David

    2008-03-01

    Active cellular transport is a fundamental mechanism for protein and vesicle delivery, cell cycle, and molecular degradation. Viruses can hijack the transport system and use it to reach the nucleus. Most transport processes consist of intermittent dynamics, where the motion of a particle, such as a virus, alternates between pure Brownian and directed movement along microtubules. In this Rapid Communication, we estimate the mean time for a particle to attach to a microtubule network. This computation leads to a coarse grained equation of the intermittent motion in radial and cylindrical geometries. Finally, by using the degradation activity inside the cytoplasm, we obtain refined asymptotic estimations for the probability and the mean time a virus reaches a small nuclear pore. PMID:18517320

  3. Inborn errors of cytoplasmic triglyceride metabolism.

    PubMed

    Wu, Jiang Wei; Yang, Hao; Wang, Shu Pei; Soni, Krishnakant G; Brunel-Guitton, Catherine; Mitchell, Grant A

    2015-01-01

    Triglyceride (TG) synthesis, storage, and degradation together constitute cytoplasmic TG metabolism (CTGM). CTGM is mostly studied in adipocytes, where starting from glycerol-3-phosphate and fatty acyl (FA)-coenzyme A (CoA), TGs are synthesized then stored in cytoplasmic lipid droplets. TG hydrolysis proceeds sequentially, producing FAs and glycerol. Several reactions of CTGM can be catalyzed by more than one enzyme, creating great potential for complex tissue-specific physiology. In adipose tissue, CTGM provides FA as a systemic energy source during fasting and is related to obesity. Inborn errors and mouse models have demonstrated the importance of CTGM for non-adipose tissues, including skeletal muscle, myocardium and liver, because steatosis and dysfunction can occur. We discuss known inborn errors of CTGM, including deficiencies of: AGPAT2 (a form of generalized lipodystrophy), LPIN1 (childhood rhabdomyolysis), LPIN2 (an inflammatory condition, Majeed syndrome, described elsewhere in this issue), DGAT1 (protein loosing enteropathy), perilipin 1 (partial lipodystrophy), CGI-58 (gene ABHD5, neutral lipid storage disease (NLSD) with ichthyosis and "Jordan's anomaly" of vacuolated polymorphonuclear leukocytes), adipose triglyceride lipase (ATGL, gene PNPLA2, NLSD with myopathy, cardiomyopathy and Jordan's anomaly), hormone-sensitive lipase (HSL, gene LIPE, hypertriglyceridemia, and insulin resistance). Two inborn errors of glycerol metabolism are known: glycerol kinase (GK, causing pseudohypertriglyceridemia) and glycerol-3-phosphate dehydrogenase (GPD1, childhood hepatic steatosis). Mouse models often resemble human phenotypes but may diverge markedly. Inborn errors have been described for less than one-third of CTGM enzymes, and new phenotypes may yet be identified. PMID:25300978

  4. Cytoplasmic membrane response to copper and nickel in Acidithiobacillus ferrooxidans.

    PubMed

    Mykytczuk, N C S; Trevors, J T; Ferroni, G D; Leduc, L G

    2011-03-20

    Metal tolerance has been found to vary among Acidithiobacillus ferrooxidans strains and this can impact the efficiency of biomining practices. To explain observed strain variability for differences in metal tolerance we examined the effects of Cu(2+) and Ni(2+) concentrations (1-200 mM) on cytoplasmic membrane properties of two A. ferrooxidans type strains (ATCC 23270 and 19859) and four strains isolated from AMD water around Sudbury, Ontario, Canada. Growth rate, membrane fluidity and phase, determined from the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), and fatty acid profiles indicated that three different modes of adaptation were present and could separate between strains showing moderate, or high metal tolerance from more sensitive strains. To compensate for the membrane ordering effects of the metals, significant remodelling of the membrane was used to either maintain homeoviscous adaptation in the moderately tolerant strains or to increase membrane fluidity in the sensitive strains. Shifts in the gel-to-liquid crystalline transition temperature in the moderately tolerant strains led to multiple phase transitions, increasing the potential for phase separation and compromised membrane integrity. The metal-tolerant strain however, was able to tolerate increases in membrane order without significant compensation via fatty acid composition. Our multivariate analyses show a common adaptive response which involves changes in the abundant 16:0 and 18:1 fatty acids. However, fatty acid composition and membrane properties showed no difference in response to either copper or nickel suggesting that adaptive response was non-specific and tolerance dependent. We demonstrate that strain variation can be evaluated using differences in membrane properties as intrinsic determinants of metal susceptibility. PMID:20630730

  5. DGKζ under stress conditions: “to be nuclear or cytoplasmic, that is the question”.

    PubMed

    Goto, Kaoru; Tanaka, Toshiaki; Nakano, Tomoyuki; Okada, Masashi; Hozumi, Yasukazu; Topham, Matthew K; Martelli, Alberto M

    2014-01-01

    Eukaryotic cells have evolved to possess a distinct subcellular compartment, the nucleus, separated from the cytoplasm in a manner that allows the precise operation of the chromatin, thereby permitting controlled access to the regulatory elements in the DNA for transcription and replication. In the cytoplasm, genetic information contained in the DNA sequence is translated into proteins, including enzymes that catalyze various reactions, such as metabolic processes, energy control, and responses to changing environments. One mechanism that regulates these events involves phosphoinositide turnover signaling, which generates a lipid second messenger, diacylglycerol (DG). Since DG acts as a potent activator of several signaling molecules, it should be tightly regulated to keep cellular responsiveness within a physiological range. DG kinase (DGK) metabolizes DG by phosphorylating it to generate phosphatidic acid, thus serving as a critical regulator of DG signaling. Phosphoinositide turnover is employed differentially in the nucleus and the cytoplasm. A member of the DGK family, DGKζ, localizes to the nucleus in various cell types and is considered to regulate nuclear DG signaling. Recent studies have provided evidence that DGKζ shuttles between the nucleus and the cytoplasm in neurons under pathophysiological conditions. Transport of a signal regulator between the nucleus and the cytoplasm should be a critical function for maintaining basic processes in the nucleus, such as cell cycle regulation and gene expression, and to ensure communication between nuclear processes and cytoplasmic functions. In this review, a series of studies on nucleocytoplasmic translocation of DGKζ have been summarized, and the functional implications of this phenomenon in postmitotic neurons and cancer cells under stress conditions are discussed. PMID:24119575

  6. Cytoplasmic location of α1A voltage-gated calcium channel C-terminal fragment (Cav2.1-CTF) aggregate is sufficient to cause cell death.

    PubMed

    Takahashi, Makoto; Obayashi, Masato; Ishiguro, Taro; Sato, Nozomu; Niimi, Yusuke; Ozaki, Kokoro; Mogushi, Kaoru; Mahmut, Yasen; Tanaka, Hiroshi; Tsuruta, Fuminori; Dolmetsch, Ricardo; Yamada, Mitsunori; Takahashi, Hitoshi; Kato, Takeo; Mori, Osamu; Eishi, Yoshinobu; Mizusawa, Hidehiro; Ishikawa, Kinya

    2013-01-01

    The human α1A voltage-dependent calcium channel (Cav2.1) is a pore-forming essential subunit embedded in the plasma membrane. Its cytoplasmic carboxyl(C)-tail contains a small poly-glutamine (Q) tract, whose length is normally 4∼19 Q, but when expanded up to 20∼33Q, the tract causes an autosomal-dominant neurodegenerative disorder, spinocerebellar ataxia type 6 (SCA6). A recent study has shown that a 75-kDa C-terminal fragment (CTF) containing the polyQ tract remains soluble in normal brains, but becomes insoluble mainly in the cytoplasm with additional localization to the nuclei of human SCA6 Purkinje cells. However, the mechanism by which the CTF aggregation leads to neurodegeneration is completely elusive, particularly whether the CTF exerts more toxicity in the nucleus or in the cytoplasm. We tagged recombinant (r)CTF with either nuclear-localization or nuclear-export signal, created doxycyclin-inducible rat pheochromocytoma (PC12) cell lines, and found that the CTF is more toxic in the cytoplasm than in the nucleus, the observations being more obvious with Q28 (disease range) than with Q13 (normal-length). Surprisingly, the CTF aggregates co-localized both with cAMP response element-binding protein (CREB) and phosphorylated-CREB (p-CREB) in the cytoplasm, and Western blot analysis showed that the quantity of CREB and p-CREB were both decreased in the nucleus when the rCTF formed aggregates in the cytoplasm. In human brains, polyQ aggregates also co-localized with CREB in the cytoplasm of SCA6 Purkinje cells, but not in other conditions. Collectively, the cytoplasmic Cav2.1-CTF aggregates are sufficient to cause cell death, and one of the pathogenic mechanisms may be abnormal CREB trafficking in the cytoplasm and reduced CREB and p-CREB levels in the nuclei. PMID:23505410

  7. [Tail Plane Icing

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Aviation Safety Program initiated by NASA in 1997 has put greater emphasis in safety related research activities. Ice-contaminated-tailplane stall (ICTS) has been identified by the NASA Lewis Icing Technology Branch as an important activity for aircraft safety related research. The ICTS phenomenon is characterized as a sudden, often uncontrollable aircraft nose- down pitching moment, which occurs due to increased angle-of-attack of the horizontal tailplane resulting in tailplane stall. Typically, this phenomenon occurs when lowering the flaps during final approach while operating in or recently departing from icing conditions. Ice formation on the tailplane leading edge can reduce tailplane angle-of-attack range and cause flow separation resulting in a significant reduction or complete loss of aircraft pitch control. In 1993, the Federal Aviation Authority (FAA) and NASA embarked upon a four-year research program to address the problem of tailplane stall and to quantify the effect of tailplane ice accretion on aircraft performance and handling characteristics. The goals of this program, which was completed in March 1998, were to collect aerodynamic data for an aircraft tail with and without ice contamination and to develop analytical methods for predicting the effects of tailplane ice contamination. Extensive dry air and icing tunnel tests which resulted in a database of the aerodynamic effects associated with tailplane ice contamination. Although the FAA/NASA tailplane icing program generated some answers regarding ice-contaminated-tailplane stall (ICTS) phenomena, NASA researchers have found many open questions that warrant further investigation into ICTS. In addition, several aircraft manufacturers have expressed interest in a second research program to expand the database to other tail configurations and to develop experimental and computational methodologies for evaluating the ICTS phenomenon. In 1998, the icing branch at NASA Lewis initiated a second

  8. Helicopter tail rotor noise analyses

    NASA Technical Reports Server (NTRS)

    George, A. R.; Chou, S. T.

    1986-01-01

    A study was made of helicopter tail rotor noise, particularly that due to interactions with the main rotor tip vortices, and with the fuselage separation mean wake. The tail rotor blade-main rotor tip vortex interaction is modelled as an airfoil of infinite span cutting through a moving vortex. The vortex and the geometry information required by the analyses are obtained through a free wake geometry analysis of the main rotor. The acoustic pressure-time histories for the tail rotor blade-vortex interactions are then calculated. These acoustic results are compared to tail rotor loading and thickness noise, and are found to be significant to the overall tail rotor noise generation. Under most helicopter operating conditions, large acoustic pressure fluctuations can be generated due to a series of skewed main rotor tip vortices passing through the tail rotor disk. The noise generation depends strongly upon the helicopter operating conditions and the location of the tail rotor relative to the main rotor.

  9. Internal Sense of Direction: Sensing and Signaling from Cytoplasmic Chemoreceptors

    PubMed Central

    Collins, Kieran D.; Lacal, Jesus

    2014-01-01

    SUMMARY Chemoreceptors sense environmental signals and drive chemotactic responses in Bacteria and Archaea. There are two main classes of chemoreceptors: integral inner membrane and soluble cytoplasmic proteins. The latter were identified more recently than integral membrane chemoreceptors and have been studied much less thoroughly. These cytoplasmic chemoreceptors are the subject of this review. Our analysis determined that 14% of bacterial and 43% of archaeal chemoreceptors are cytoplasmic, based on currently sequenced genomes. Cytoplasmic chemoreceptors appear to share the same key structural features as integral membrane chemoreceptors, including the formations of homodimers, trimers of dimers, and 12-nm hexagonal arrays within the cell. Cytoplasmic chemoreceptors exhibit varied subcellular locations, with some localizing to the poles and others appearing both cytoplasmic and polar. Some cytoplasmic chemoreceptors adopt more exotic locations, including the formations of exclusively internal clusters or moving dynamic clusters that coalesce at points of contact with other cells. Cytoplasmic chemoreceptors presumably sense signals within the cytoplasm and bear diverse signal input domains that are mostly N terminal to the domain that defines chemoreceptors, the so-called MA domain. Similar to the case for transmembrane receptors, our analysis suggests that the most common signal input domain is the PAS (Per-Arnt-Sim) domain, but a variety of other N-terminal domains exist. It is also common, however, for cytoplasmic chemoreceptors to have C-terminal domains that may function for signal input. The most common of these is the recently identified chemoreceptor zinc binding (CZB) domain, found in 8% of all cytoplasmic chemoreceptors. The widespread nature and diverse signal input domains suggest that these chemoreceptors can monitor a variety of cytoplasmically based signals, most of which remain to be determined. PMID:25428939

  10. Evidence for a cytoplasmic pathway of oxalate biosynthesis in Aspergillus niger

    SciTech Connect

    Kubicek, C.P.; Schreferl-Kunar, G.; Woehrer, W.; Roehr, M.

    1988-03-01

    Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of P/sub i/ and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added /sup 14/CO/sub 2/ was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle.

  11. Mercury's Dynamic Magnetic Tail

    NASA Technical Reports Server (NTRS)

    Slavin, James A.

    2010-01-01

    The Mariner 10 and MESSENGER flybys of Mercury have revealed a magnetosphere that is likely the most responsive to upstream interplanetary conditions of any in the solar system. The source of the great dynamic variability observed during these brief passages is due to Mercury's proximity to the Sun and the inverse proportionality between reconnection rate and solar wind Alfven Mach number. However, this planet's lack of an ionosphere and its small physical dimensions also contribute to Mercury's very brief Dungey cycle, approx. 2 min, which governs the time scale for internal plasma circulation. Current observations and understanding of the structure and dynamics of Mercury's magnetotail are summarized and discussed. Special emphasis will be placed upon such questions as: 1) How much access does the solar wind have to this small magnetosphere as a function of upstream conditions? 2) What roles do heavy planetary ions play? 3) Do Earth-like substorms take place at Mercury? 4) How does Mercury's tail respond to extreme solar wind events such coronal mass ejections? Prospects for progress due to advances in the global magnetohydrodynamic and hybrid simulation modeling and the measurements to be taken by MESSENGER after it enters Mercury orbit on March 18, 2011 will be discussed.

  12. Characterization of the cytoplasmic filament protein gene (cfpA) of Treponema pallidum subsp. pallidum.

    PubMed Central

    You, Y; Elmore, S; Colton, L L; Mackenzie, C; Stoops, J K; Weinstock, G M; Norris, S J

    1996-01-01

    Treponema pallidum and other members of the genera Treponema, Spirochaeta, and Leptonema contain multiple cytoplasmic filaments that run the length of the organism just underneath the cytoplasmic membrane. These cytoplasmic filaments have a ribbon-like profile and consist of a major cytoplasmic filament protein subunit (CfpA, formerly called TpN83) with a relative molecular weight of approximately 80,000. Degenerate DNA primers based on N-terminal and CNBr cleavage fragment amino acid sequences of T. pallidum subsp. pallidum (Nichols) CfpA were utilized to amplify a fragment of the encoding gene (cfpA). A 6.8-kb EcoRI fragment containing all but the 5' end of cfpA was identified by hybridization with the resulting PCR product and cloned into Lambda ZAP II. The 5' region was obtained by inverse PCR, and the complete gene sequence was determined. The cfpA sequence contained a 2,034-nucleotide coding region, a putative promoter with consensus sequences (5'-TTTACA-3' for -35 and 5'-TACAAT-3' for -10) similar to the sigma70 recognition sequence of Escherichia coli and other organisms, and a putative ribosome-binding site (5'-AGGAG-3'). The deduced amino acid sequence of CfpA indicated a protein of 678 residues with a calculated molecular mass of 78.5 kDa and an estimated pI of 6.15. No significant homology to known proteins or structural motifs was found among known prokaryotic or eukaryotic sequences. Expression of a LacZ-CfpA fusion protein in E. coli was detrimental to survival and growth of the host strain and resulted in the formation of short, irregular filaments suggestive of partial self-assembly of CfpA. The cytoplasmic filaments of T. pallidum and other spirochetes appear to represent a unique form of prokaryotic intracytoplasmic inclusions. PMID:8655496

  13. Caffeic acid 3,4-dihydroxy-phenethyl ester suppresses receptor activator of NF-κB ligand–induced osteoclastogenesis and prevents ovariectomy-induced bone loss through inhibition of mitogen-activated protein kinase/activator protein 1 and Ca2+–nuclear factor of activated T-cells cytoplasmic 1 signaling pathways.

    PubMed

    Wu, Xian; Li, Zhenxi; Yang, Zhengfang; Zheng, Chunbing; Jing, Ji; Chen, Yihua; Ye, Xiyun; Lian, Xiaoyuan; Qiu, Wenwei; Yang, Fan; Tang, Jie; Xiao, Jianru; Liu, Mingyao; Luo, Jian

    2012-06-01

    Receptor activator of NF-κB ligand (RANKL) stimulation leads to the activation of mitogen-activated protein kinase (MAPK)/AP-1 and Ca2+–nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) signaling pathways in osteoclastogenesis. Targeting these pathways has been an encouraging strategy for bone-related diseases, such as postmenopausal osteoporosis. In this study, we examined the effects of caffeic acid 3,4-dihydroxy-phenethyl ester (CADPE) on osteoclastogenesis. In mouse bone marrow monocytes (BMMs) and RAW264.7 cells, CADPE suppressed RANKL-induced osteoclast differentiation and actin-ring formation in a dose-dependent manner within non–growth inhibitory concentrations at the early stage, while CADPE had no effect on macrophage colony-stimulating factor (M-CSF)-induced proliferation and differentiation. At the molecular level, CADPE inhibited RANKL-induced phosphorylation of MAPKs, including extracellular signal-regulated kinases 1/2 (ERK1/2), p38, and c-Jun N-terminal kinase (JNK), without significantly affecting the NF-κB signaling pathway. CADPE abrogated RANKL-induced activator protein 1 (AP-1)/FBJ murine osteosarcoma viral oncogene homolog (c-Fos) nuclear translocation and activation. Overexpression of c-Fos prevented the inhibition by CADPE of osteoclast differentiation. Furthermore, CADPE suppressed RANKL-induced the tumor necrosis factor receptor associated factor 6 (TRAF6) interaction with c-src tyrosine kinase (c-Src), blocked RANKL-induced the phosphorylation of protein kinase B (AKT), and inhibited RANKL-induced Ca2+ oscillation. As a result, CADPE decreased osteoclastogenesis-related marker gene expression, including NFATc1, TRAP, cathepsin K, and c-Src. To test the effects of CADPE on osteoclast activity in vivo, we showed that CADPE prevented ovariectomy-induced bone loss by inhibiting osteoclast activity. Together, our data demonstrate that CADPE suppresses osteoclastogenesis and bone loss through inhibiting RANKL-induced MAPKs and Ca

  14. Native plant restoration of biosolids-amended copper mine tailings

    SciTech Connect

    Kramer, P.A.; Zabowski, D.; Everett, R.L.; Scherer, G.

    1998-12-31

    Copper mine tailings are difficult to revegetate due to nutrient deficiencies, high levels of acidity, and potential metal toxicities. An amendment of biosolids could ameliorate these harsh growing conditions through the addition of available nutrients, improvement of physical soil properties (e.g., increased water holding capacity), and possible lowering of toxic metal availability through complexation with organic matter. A study was conducted on mine tailings at Holden, WA to evaluate the effect of an amendment of biosolids on the survival and growth of five native plant species (Sitka alder, big leaf maple, fireweed, w. yarrow, and pearly everlasting). Plots were established in tailings, gravel over tailings (G/T), and biosolids plus gravel over tailings. Each of the native plant species, except maple, had their highest survival in the biosolids-amended plot with 3 species at 100% survival. The biosolids amendment was shown to improve the growth of all species except maple. Fireweed produced 62 times more biomass in the biosolids-amended plot compared to the unamended plot (G/T). Plant analysis revealed a dramatic increase in nutrient content with the amendment of biosolids. Biosolids improved the survival, growth, and nutritional status of native plant species on the copper mine tailings.

  15. Vegetation successfully prevents oxidization of sulfide minerals in mine tailings.

    PubMed

    Li, Yang; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

    2016-07-15

    The oxidization of metal sulfide in tailings causes acid mine drainage. However, it remains unclear whether vegetation prevents the oxidization of metal sulfides. The oxidization characteristics and microbial indices of the tailings in the presence of various plant species were investigated to explore the effects of vegetation on the oxidization of sulfide minerals in tailings. The pH, reducing sulfur, free iron oxides (Fed), chemical oxygen consumption (COC) and biological oxygen consumption (BOC) were measured. Key iron- and sulfur-oxidizing bacteria (Acidithiobacillus spp., Leptospirillum spp. and Thiobacillus spp.) were quantified using real-time PCR. The results indicate that vegetation growing on tailings can effectively prevent the oxidization of sulfide minerals in tailings. A higher pH and reducing-sulfur content and lower Fed were observed in the 0-30 cm depth interval in the presence of vegetation compared to bare tailings (BT). The COC gradually decreased with depth in all of the soil profiles; specifically, the COC rapidly decreased in the 10-20 cm interval in the presence of vegetation but gradually decreased in the BT profiles. Imperata cylindrica (IC) and Chrysopogon zizanoides (CZ) profiles contained the highest BOC in the 10-20 cm interval. The abundance of key iron- and sulfur-oxidizing bacteria in the vegetated tailings were significantly lower than in the BT; in particular, IC was associated with the lowest iron- and sulfur-oxidizing bacterial abundance. In conclusion, vegetation successfully prevented the oxidization of sulfide minerals in the tailings, and Imperata cylindrica is the most effective in reducing the number of iron- and sulfur-oxidizing bacteria and helped to prevent the oxidization of sulfide minerals in the long term. PMID:27093236

  16. Plant Growth-Promoting Bacteria for Phytostabilization of Mine Tailings

    SciTech Connect

    Grandlic, C.J.; Mendez, M.O.; Chorover, J.; Machado, B.; Maier, R.M.

    2009-05-19

    Eolian dispersion of mine tailings in arid and semiarid environments is an emerging global issue for which economical remediation alternatives are needed. Phytostabilization, the revegetation of these sites with native plants, is one such alternative. Revegetation often requires the addition of bulky amendments such as compost which greatly increases cost. We report the use of plant growth-promoting bacteria (PGPB) to enhance the revegetation of mine tailings and minimize the need for compost amendment. Twenty promising PGPB isolates were used as seed inoculants in a series of greenhouse studies to examine revegetation of an extremely acidic, high metal content tailings sample previously shown to require 15% compost amendment for normal plant growth. Several isolates significantly enhanced growth of two native species, quailbush and buffalo grass, in tailings. In this study, PGPB/compost outcomes were plant specific; for quailbush, PGPB were most effective in combination with 10% compost addition while for buffalo grass, PGPB enhanced growth in the complete absence of compost. Results indicate that selected PGPB can improve plant establishment and reduce the need for compost amendment. Further, PGPB activities necessary for aiding plant growth in mine tailings likely include tolerance to acidic pH and metals.

  17. Fat mass and obesity-related (FTO) shuttles between the nucleus and cytoplasm

    PubMed Central

    Gulati, Pawan; Avezov, Edward; Ma, Marcella; Antrobus, Robin; Lehner, Paul; O’Rahilly, Stephen; Yeo, Giles S. H.

    2014-01-01

    SNPs (single nucleotide polymorphisms) on a chromosome 16 locus encompassing FTO, as well as IRX3, 5, 6, FTM and FTL are robustly associated with human obesity. FTO catalyses the Fe(II)- and 2OG-dependent demethylation of RNA and is an AA (amino acid) sensor that couples AA levels to mTORC1 (mammalian target of rapamycin complex 1) signalling, thereby playing a key role in regulating growth and translation. However, the cellular compartment in which FTO primarily resides to perform its biochemical role is unclear. Here, we undertake live cell imaging of GFP (green fluorescent protein)-FTO, and demonstrate that FTO resides in both the nucleus and cytoplasm. We show using ‘FLIP’ (fluorescence loss in photobleaching) that a mobile FTO fraction shuttles between both compartments. We performed a proteomic study and identified XPO2 (Exportin 2), one of a family of proteins that mediates the shuttling of proteins between the nucleus and the cytoplasm, as a binding partner of FTO. Finally, using deletion studies, we show that the N-terminus of FTO is required for its ability to shuttle between the nucleus and cytoplasm. In conclusion, FTO is present in both the nucleus and cytoplasm, with a mobile fraction that shuttles between both cellular compartments, possibly by interaction with XPO2. PMID:25242086

  18. Molecular analysis of cytoplasmic male sterility

    SciTech Connect

    Hanson, M.R.

    1990-01-01

    The ultimate aims of the project are to understand the molecular mechanism of the disruption in pollen development which occurs in cytoplasmic male sterile plants and to understand the control of respiratory energy flow in the higher plant cell. A mitochondrial locus termed S-pcf segregates with sterility and with an alteration in respiration in Petunia. This cloned locus contains three genes, an abnormal fused gene termed pcf, a gene for a subunit of an NADH dehydrogenase complex, and a small ribosomal subunit protein. The pcf gene is comprised of partial sequences of ATPase subunit 9, cytochrome oxidase subunit II, and an unidentified reading frame. Components of the S-Pcf locus will be introduced into the nuclear of a fertile genotype under the control of appropriate regulatory signals, and polypeptide products of introduced genes will be directed to the mitochondrion with a transit peptide. By examining transgenic plants, we can determine what elements of the locus are critical for altered respiration or sterility. Such knowledge could explain how mitochondrial DNA affects pollen development in the large number of plant species which exhibit the agronomically important trait of male sterility. 10 refs., 3 figs.

  19. The synthesis of polyribonucleotides by cytoplasmic enzymes

    PubMed Central

    Wykes, J. R.; Smellie, R. M. S.

    1966-01-01

    1. The possibility that the cell cytoplasm contains enzymes catalysing the biosynthesis of RNA was investigated in fractions obtained by differential centrifugation of homogenates of Landschutz ascites-tumour cells. 2. The microsomal fraction was shown to be most active in incorporating UMP residues from [α-32P]UTP into polyribonucleotide material. 3. The same fraction also incorporated [3H]CTP, [3H]ATP and [3H]GTP separately and independently of the presence of complementary ribonucleoside 5′-triphosphates. 4. The reaction was promoted by the addition of RNA and showed an absolute requirement for Mg2+ ions. 5. Analysis of alkaline hydrolysates of the reaction products after the incorporation of [α-32P]UTP showed that most of the radioactivity was recovered in (2′,3′)-UMP residues irrespective of whether CTP, ATP and GTP were present in the reaction mixture. 6. Extraction of RNA from the reaction mixtures after the incorporation of [3H]ATP, [3H]GTP or [3H]CTP and analysis by sucrosedensity-gradient centrifugation showed no labelling of the ribosomal RNA. Radioactive material appeared between the 4s region and the meniscus of the sucrose gradient. In agreement with this observation, determinations of the chain length of the product showed that only short sequences of polynucleotides were synthesized. It is concluded that only homopolyribonucleotide synthesis is catalysed by the microsomal fractions and that there is little or no synthesis of RNA-like heteropolymers. PMID:5947148

  20. Tropomyosin-Mediated Regulation of Cytoplasmic Myosins.

    PubMed

    Manstein, Dietmar J; Mulvihill, Daniel P

    2016-08-01

    The ability of the actin-based cytoskeleton to rapidly reorganize is critical for maintaining cell organization and viability. The plethora of activities in which actin polymers participate require different biophysical properties, which can vary significantly between the different events that often occur simultaneously at separate cellular locations. In order to modify the biophysical properties of an actin polymer for a particular function, the cell contains diverse actin-binding proteins that modulate the growth, regulation and molecular interactions of actin-based structures according to functional requirements. In metazoan and yeast cells, tropomyosin is a key regulator of actin-based structures. Cells have the capacity to produce multiple tropomyosin isoforms, each capable of specifically associating as copolymers with actin at distinct cellular locations to fine-tune the functional properties of discrete actin structures. Here, we present a unifying theory in which tropomyosin isoforms critically define the surface landscape of copolymers with cytoplasmic β- or γ-actin. Decoration of filamentous actin with different tropomyosin isoforms determines the identity and modulates the activity of the interacting myosin motor proteins. Conversely, changes in the nucleotide state of actin and posttranslational modifications affect the composition, morphology, subcellular localization and allosteric coupling of the associated actin-based superstructures. PMID:27060364

  1. Cytoplasmic mRNA turnover and ageing

    PubMed Central

    Borbolis, Fivos; Syntichaki, Popi

    2015-01-01

    Messenger RNA (mRNA) turnover that determines the lifetime of cytoplasmic mRNAs is a means to control gene expression under both normal and stress conditions, whereas its impact on ageing and age-related disorders has just become evident. Gene expression control is achieved at the level of the mRNA clearance as well as mRNA stability and accessibility to other molecules. All these processes are regulated by cis-acting motifs and trans-acting factors that determine the rates of translation and degradation of transcripts. Specific messenger RNA granules that harbor the mRNA decay machinery or various factors, involved in translational repression and transient storage of mRNAs, are also part of the mRNA fate regulation. Their assembly and function can be modulated to promote stress resistance to adverse conditions and over time affect the ageing process and the lifespan of the organism. Here, we provide insights into the complex relationships of ageing modulators and mRNA turnover mechanisms. PMID:26432921

  2. A physical perspective on cytoplasmic streaming

    PubMed Central

    Goldstein, Raymond E.; van de Meent, Jan-Willem

    2015-01-01

    Organisms show a remarkable range of sizes, yet the dimensions of a single cell rarely exceed 100 µm. While the physical and biological origins of this constraint remain poorly understood, exceptions to this rule give valuable insights. A well-known counterexample is the aquatic plant Chara, whose cells can exceed 10 cm in length and 1 mm in diameter. Two spiralling bands of molecular motors at the cell periphery drive the cellular fluid up and down at speeds up to 100 µm s−1, motion that has been hypothesized to mitigate the slowness of metabolite transport on these scales and to aid in homeostasis. This is the most organized instance of a broad class of continuous motions known as ‘cytoplasmic streaming’, found in a wide range of eukaryotic organisms—algae, plants, amoebae, nematodes and flies—often in unusually large cells. In this overview of the physics of this phenomenon, we examine the interplay between streaming, transport and cell size and discuss the possible role of self-organization phenomena in establishing the observed patterns of streaming. PMID:26464789

  3. Evolution of Wolbachia cytoplasmic incompatibility types.

    PubMed

    Dobson, Stephen L

    2004-10-01

    The success of obligate endosymbiotic Wolbachia infections in insects is due in part to cytoplasmic incompatibility (CI), whereby Wolbachia bacteria manipulate host reproduction to promote their invasion and persistence within insect populations. The observed diversity of CI types raises the question of what the evolutionary pathways are by which a new CI type can evolve from an ancestral type. Prior evolutionary models assume that Wolbachia exists within a host individual as a clonal infection. While endosymbiotic theory predicts a general trend toward clonality, Wolbachia provides an exception in which there is selection to maintain diversity. Here, evolutionary trajectories are discussed that assume that a novel Wolbachia variant will co-exist with the original infection type within a host individual as a superinfection. Relative to prior models, this assumption relaxes requirements and allows additional pathways for the evolution of novel CI types. In addition to describing changes in the Wolbachia infection frequency associated with the hypothesized evolutionary events, the predicted impact of novel CI variants on the host population is also described. This impact, resulting from discordant evolutionary interests of symbiont and host, is discussed as a possible cause of Wolbachia loss from the host population or host population extinction. The latter is also discussed as the basis for an applied strategy for the suppression of insect pest populations. Model predictions are discussed relative to a recently published Wolbachia genome sequence and prior characterization of CI in naturally and artificially infected insects. PMID:15562682

  4. Cytoplasmic Adenylation and Processing of Maternal RNA

    PubMed Central

    Slater, Isabel; Gillespie, David; Slater, D. W.

    1973-01-01

    Molecular hybridization between [3H]-poly(U) and unlabeled RNA prepared from sea urchin eggs and embryos has been used to contrast the subcellular localization as well as the size distribution of adenylylated maternal RNA preexisting in the unfertilized egg with that adenylylated as a function of fertilization. Evidence reported establishes that such preadenylylated genetic messages are predominantly located in the ovum's subribosomal fraction and that fertilization elicits a rapid reallocation of these latent transcripts into the zygote's ribosomal fraction. Examination of the size distribution of the adenylylated RNA further demonstrates that the unfertilized egg contains a substantial population of RNA transcripts of exceptionally high molecular weight that are used as primers for the 2-fold net synthesis of poly(A) that follows fertilization. The poly(A)-rich tracts are shown to be covalently bonded to RNA. Assessment of the poly(A) content of nuclear and cytoplasmic fractions suggests that the function of poly(A) is not confined to the transport of genetic messages from the nucleus. PMID:4510284

  5. Substrate Specificity of Cytoplasmic N-Glycosyltransferase*

    PubMed Central

    Naegeli, Andreas; Michaud, Gaëlle; Schubert, Mario; Lin, Chia-Wei; Lizak, Christian; Darbre, Tamis; Reymond, Jean-Louis; Aebi, Markus

    2014-01-01

    N-Linked protein glycosylation is a very common post-translational modification that can be found in all kingdoms of life. The classical, highly conserved pathway entails the assembly of a lipid-linked oligosaccharide and its transfer to an asparagine residue in the sequon NX(S/T) of a secreted protein by the integral membrane protein oligosaccharyltransferase. A few species in the class of γ-proteobacteria encode a cytoplasmic N-glycosylation system mediated by a soluble N-glycosyltransferase (NGT). This enzyme uses nucleotide-activated sugars to modify asparagine residues with single monosaccharides. As these enzymes are not related to oligosaccharyltransferase, NGTs constitute a novel class of N-glycosylation catalyzing enzymes. To characterize the NGT-catalyzed reaction, we developed a sensitive and quantitative in vitro assay based on HPLC separation and quantification of fluorescently labeled substrate peptides. With this assay we were able to directly quantify glycopeptide formation by Actinobacillus pleuropneumoniae NGT and determine its substrate specificities: NGT turns over a number of different sugar donor substrates and allows for activation by both UDP and GDP. Quantitative analysis of peptide substrate turnover demonstrated a strikingly similar specificity as the classical, oligosaccharyltransferase-catalyzed N-glycosylation, with NX(S/T) sequons being the optimal NGT substrates. PMID:24962585

  6. Cytoplasmic dynein promotes HIV-1 uncoating.

    PubMed

    Pawlica, Paulina; Berthoux, Lionel

    2014-11-01

    Retroviral capsid (CA) cores undergo uncoating during their retrograde transport (toward the nucleus), and/or after reaching the nuclear membrane. However, whether HIV-1 CA core uncoating is dependent upon its transport is not understood. There is some evidence that HIV-1 cores retrograde transport involves cytoplasmic dynein complexes translocating on microtubules. Here we investigate the role of dynein-dependent transport in HIV-1 uncoating. To interfere with dynein function, we depleted dynein heavy chain (DHC) using RNA interference, and we over-expressed p50/dynamitin. In immunofluorescence microscopy experiments, DHC depletion caused an accumulation of CA foci in HIV-1 infected cells. Using a biochemical assay to monitor HIV-1 CA core disassembly in infected cells, we observed an increase in amounts of intact (pelletable) CA cores upon DHC depletion or p50 over-expression. Results from these two complementary assays suggest that inhibiting dynein-mediated transport interferes with HIV-1 uncoating in infected cells, indicating the existence of a functional link between HIV-1 transport and uncoating. PMID:25375884

  7. Morphogenesis of the T4 tail and tail fibers

    PubMed Central

    2010-01-01

    Remarkable progress has been made during the past ten years in elucidating the structure of the bacteriophage T4 tail by a combination of three-dimensional image reconstruction from electron micrographs and X-ray crystallography of the components. Partial and complete structures of nine out of twenty tail structural proteins have been determined by X-ray crystallography and have been fitted into the 3D-reconstituted structure of the "extended" tail. The 3D structure of the "contracted" tail was also determined and interpreted in terms of component proteins. Given the pseudo-atomic tail structures both before and after contraction, it is now possible to understand the gross conformational change of the baseplate in terms of the change in the relative positions of the subunit proteins. These studies have explained how the conformational change of the baseplate and contraction of the tail are related to the tail's host cell recognition and membrane penetration function. On the other hand, the baseplate assembly process has been recently reexamined in detail in a precise system involving recombinant proteins (unlike the earlier studies with phage mutants). These experiments showed that the sequential association of the subunits of the baseplate wedge is based on the induced-fit upon association of each subunit. It was also found that, upon association of gp53 (gene product 53), the penultimate subunit of the wedge, six of the wedge intermediates spontaneously associate to form a baseplate-like structure in the absence of the central hub. Structure determination of the rest of the subunits and intermediate complexes and the assembly of the hub still require further study. PMID:21129200

  8. Use of cemented paste backfill in arsenic-rich tailings

    NASA Astrophysics Data System (ADS)

    Hamberg, Roger; Maurice, Christian; Alakangas, Lena

    2015-04-01

    Gold is extracted by cyanide leaching from inclusions in arsenopyrite from a mine in the north of Sweden. The major ore mineral assemblage consists of pyrrhotite and arsenopyrite-loellingite. Effluents from the gold extraction were treated with Fe2(SO4)3, with the aim to form stable As-bearing Fe-precipitates (FEP). The use of the method called cemented paste backfill (CPB) is sometimes suggested for the management of tailings. In CPB, tailings are commonly mixed with low proportions (3 - 7 %) of cement and backfilled into underground excavated area. To reduce costs, amendments such as granulated blast furnace slag (GBFS), biofuel fly ash (BFA) and cement kiln dust (CKD) are used for partial replacement of cement in CPB due to their pozzolanic and alkaline properties. The objective for this study was to evaluate the leaching behaviour of As in CPB-mixtures with low proportions (1 - 3 %) of BFA and ordinary cement and unmodified tailings. The selection of CPB-recipies was made based on technical and economical criterias to adress the demands deriving from the mining operations. Speciation of the As in ore and tailings samples revealed that mining processes have dissolved the majority of the arsenopyrite in the ore, causing secondary As phases to co-precipitate with newly formed FEP:s. Tank leaching tests (TLT) and weathering cells (WCT) were used to compare leaching behaviour in a monolithic mass contra a crushed material. Quantification of the presumed benefit of CPB was made by calculation of the cumulative leaching of As. Results from the leaching tests (TLT and WCT) showed that the inclusion of As-rich tailings into a cementitious matrix increased leaching of As. This behaviour could partially be explained by an increase of pH. The addition of alkaline binder materials to tailings increased As leaching due to the relocation of desorbed As from FEPs into less acid-tolerant species such as Ca-arsenates and cementitious As-phases. Unmodified tailings generated an

  9. Can paternal leakage maintain sexually antagonistic polymorphism in the cytoplasm?

    PubMed Central

    Kuijper, B; Lane, N; Pomiankowski, A

    2015-01-01

    A growing number of studies in multicellular organisms highlight low or moderate frequencies of paternal transmission of cytoplasmic organelles, including both mitochondria and chloroplasts. It is well established that strict maternal inheritance is selectively blind to cytoplasmic elements that are deleterious to males – ’mother's curse’. But it is not known how sensitive this conclusion is to slight levels of paternal cytoplasmic leakage. We assess the scope for polymorphism when individuals bear multiple cytoplasmic alleles in the presence of paternal leakage, bottlenecks and recurrent mutation. When fitness interactions among cytoplasmic elements within an individual are additive, we find that sexually antagonistic polymorphism is restricted to cases of strong selection on males. However, when fitness interactions among cytoplasmic elements are nonlinear, much more extensive polymorphism can be supported in the cytoplasm. In particular, mitochondrial mutants that have strong beneficial fitness effects in males and weak deleterious fitness effects in females when rare (i.e. ’reverse dominance’) are strongly favoured under paternal leakage. We discuss how such epistasis could arise through preferential segregation of mitochondria in sex-specific somatic tissues. Our analysis shows how paternal leakage can dampen the evolution of deleterious male effects associated with predominant maternal inheritance of cytoplasm, potentially explaining why ’mother's curse’ is less pervasive than predicted by earlier work. PMID:25653025

  10. Developing improved durum wheat germplasm by altering the cytoplasmic genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In eukaryotic organisms, nuclear and cytoplasmic genomes interact to drive cellular functions. These genomes have co-evolved to form specific nuclear-cytoplasmic interactions that are essential to the origin, success, and evolution of diploid and polyploid species. Hundreds of genetic diseases in h...

  11. Dual roles of p82, the clam CPEB homolog, in cytoplasmic polyadenylation and translational masking.

    PubMed

    Minshall, N; Walker, J; Dale, M; Standart, N

    1999-01-01

    In the transcriptionally inert maturing oocyte and early embryo, control of gene expression is largely mediated by regulated changes in translational activity of maternal mRNAs. Some mRNAs are activated in response to poly(A) tail lengthening; in other cases activation results from de-repression of the inactive or masked mRNA. The 3' UTR cis-acting elements that direct these changes are defined, principally in Xenopus and mouse, and the study of their trans-acting binding factors is just beginning to shed light on the mechanism and regulation of cytoplasmic polyadenylation and translational masking. In the marine invertebrate, Spisula solidissima, the timing of activation of three abundant mRNAs (encoding cyclin A and B and the small subunit of ribonucleotide reductase, RR) in fertilized oocytes correlates with their cytoplasmic polyadenylation. However, in vitro, mRNA-specific unmasking occurs in the absence of polyadenylation. In Walker et al. (in this issue) we showed that p82, a protein defined as selectively binding the 3' UTR masking elements, is a homolog of Xenopus CPEB (cytoplasmic polyadenylation element binding protein). In functional studies reported here, the elements that support polyadenylation in clam egg lysates include multiple U-rich CPE-like motifs as well as the nuclear polyadenylation signal AAUAAA. This represents the first detailed analysis of invertebrate cis-acting cytoplasmic polyadenylation signals. Polyadenylation activity correlates with p82 binding in wild-type and CPE-mutant RR 3' UTR RNAs. Moreover, since anti-p82 antibodies specifically neutralize polyadenylation in egg lysates, we conclude that clam p82 is a functional homolog of Xenopus CPEB, and plays a positive role in polyadenylation. Anti-p82 antibodies also result in specific translational activation of masked mRNAs in oocyte lysates, lending support to our original model of clam p82 as a translational repressor. We propose therefore that clam p82/CPEB has dual functions in

  12. Effective cytoplasmic release of siRNA from liposomal carriers by controlling the electrostatic interaction of siRNA with a charge-invertible peptide, in response to cytoplasmic pH.

    PubMed

    Itakura, Shoko; Hama, Susumu; Matsui, Ryo; Kogure, Kentaro

    2016-05-19

    Condensing siRNA with cationic polymers is a major strategy used in the development of siRNA carriers that can avoid degradation by nucleases and achieve effective delivery of siRNA into the cytoplasm. However, ineffective release of siRNA from such condensed forms into the cytoplasm is a limiting step for induction of RNAi effects, and can be attributed to tight condensation of siRNA with the cationic polymers, due to potent electrostatic interactions. Here, we report that siRNA condensed with a slightly acidic pH-sensitive peptide (SAPSP), whose total charge is inverted from positive to negative in response to cytoplasmic pH, is effectively released via electrostatic repulsion of siRNA with negatively charged SAPSP at cytoplasmic pH (7.4). The condensed complex of siRNA and positively-charged SAPSP at acidic pH (siRNA/SAPSP) was found to result in almost complete release of siRNA upon charge inversion of SAPSP at pH 7.4, with the resultant negatively-charged SAPSP having no undesirable interactions with endogenous mRNA. Moreover, liposomes encapsulating siRNA/SAPSP demonstrated knockdown efficiencies comparable to those of commercially available siRNA carriers. Taken together, SAPSP may be very useful as a siRNA condenser, as it facilitates effective cytoplasmic release of siRNA, and subsequent induction of specific RNAi effects. PMID:27145993

  13. SUBAQUEOUS DISPOSAL OF MILL TAILINGS

    SciTech Connect

    Neeraj K. Mendiratta; Roe-Hoan Yoon; Paul Richardson

    1999-09-03

    A study of mill tailings and sulfide minerals was carried out in order to understand their behavior under subaqueous conditions. A series of electrochemical experiments, namely, cyclic voltammetry, electrochemical impedance spectroscopy and galvanic coupling tests were carried out in artificial seawater and in pH 6.8 buffer solutions with chloride and ferric salts. Two mill tailings samples, one from the Kensington Mine, Alaska, and the other from the Holden Mine, Washington, were studied along with pyrite, galena, chalcopyrite and copper-activated sphalerite. SEM analysis of mill tailings revealed absence of sulfide minerals from the Kensington Mine mill tailings, whereas the Holden Mine mill tailings contained approximately 8% pyrite and 1% sphalerite. In order to conduct electrochemical tests, carbon matrix composite (CMC) electrodes of mill tailings, pyrite and galena were prepared and their feasibility was established by conducting a series of cyclic voltammetry tests. The cyclic voltammetry experiments carried out in artificial seawater and pH 6.8 buffer with chloride salts showed that chloride ions play an important role in the redox processes of sulfide minerals. For pyrite and galena, peaks were observed for the formation of chloride complexes, whereas pitting behavior was observed for the CMC electrodes of the Kensington Mine mill tailings. The electrochemical impedance spectroscopy conducted in artificial seawater provided with the Nyquist plots of pyrite and galena. The Nyquist plots of pyrite and galena exhibited an inert range of potential indicating a slower rate of leaching of sulfide minerals in marine environments. The galvanic coupling experiments were carried out to study the oxidation of sulfide minerals in the absence of oxygen. It was shown that in the absence of oxygen, ferric (Fe3+) ions might oxidize the sulfide minerals, thereby releasing undesirable oxidation products in the marine environment. The source of Fe{sup 3{minus}} ions may be

  14. Nucleotide sequence of Neurospora crassa cytoplasmic initiator tRNA.

    PubMed Central

    Gillum, A M; Hecker, L I; Silberklang, M; Schwartzbach, S D; RajBhandary, U L; Barnett, W E

    1977-01-01

    Initiator methionine tRNA from the cytoplasm of Neurospora crassa has been purified and sequenced. The sequence is: pAGCUGCAUm1GGCGCAGCGGAAGCGCM22GCY*GGGCUCAUt6AACCCGGAGm7GU (or D) - CACUCGAUCGm1AAACGAG*UUGCAGCUACCAOH. Similar to initiator tRNAs from the cytoplasm of other eukaryotes, this tRNA also contains the sequence -AUCG- instead of the usual -TphiCG (or A)- found in loop IV of other tRNAs. The sequence of the N. crassa cytoplasmic initiator tRNA is quite different from that of the corresponding mitochondrial initiator tRNA. Comparison of the sequence of N. crassa cytoplasmic initiator tRNA to those of yeast, wheat germ and vertebrate cytoplasmic initiator tRNA indicates that the sequences of the two fungal tRNAs are no more similar to each other than they are to those of other initiator tRNAs. Images PMID:146192

  15. Lipogenic Enzymes Complexes and Cytoplasmic Lipid Droplet Formation During Adipogenesis.

    PubMed

    Padilla-Benavides, Teresita; Velez-delValle, Cristina; Marsch-Moreno, Meytha; Castro-Muñozledo, Federico; Kuri-Harcuch, Walid

    2016-10-01

    Lipid droplets are dynamic organelles that store triglycerides and participate in their mobilization in adipose cells. These organelles require the reorganization of some structural components, the cytoskeleton, and the activation of lipogenic enzymes. Using confocal microscopy, we analyzed the participation of cytoskeletal components and two lipogenic enzymes, fatty acid synthase and glycerophosphate dehydrogenase, during lipid droplet biogenesis in differentiating 3T3-F442A cells into adipocytes. We show that subcortical actin microfilaments are extended at the basal side of the cells in parallel arrangement to the culture dish substrate, and that the microtubule network traverses the cytoplasm as a scaffold that supports the round shape of the mature adipocyte. By immunoprecipitation, we show that vimentin and perilipin1a associate during the early stages of the differentiation process for lipid droplet formation. We also report that the antibody against perilipin1 detected a band that might correspond to a modified form of the molecule. Finally, the cytosolic distribution and punctate organization of lipogenic enzymes and their co-localization in the proximity of lipid droplets suggest the existence of dynamic protein complexes involved in synthesis and storage of triglycerides. J. Cell. Biochem. 117: 2315-2326, 2016. © 2016 Wiley Periodicals, Inc. PMID:26928794

  16. An Alternative Phosphorylation Switch in Integrin β2 (CD18) Tail for Dok1 Binding

    NASA Astrophysics Data System (ADS)

    Gupta, Sebanti; Chit, Joel Chia-Yeong; Feng, Chen; Bhunia, Anirban; Tan, Suet-Mien; Bhattacharjya, Surajit

    2015-06-01

    Integrins are involved in cell migration and adhesion. A large number of proteins interact with the cytoplasmic tails of integrins. Dok1 is a negative regulator of integrin activation and it binds to the phosphorylated membrane proximal NxxY motif in a number of integrin β tails. The β tail of the β2 integrins contains a non-phosphorylatable NxxF motif. Hence it is unclear how Dok1 associates with the β2 integrins. We showed in this study using NMR and cell based analyses that residues Ser745 and Ser756 in the integrin β2 tail, which are adjacent to the NxxF motif, are required for Dok1 interaction. NMR analyses detected significant chemical shift changes and higher affinity interactions between Dok1 phospho-tyrosine binding (PTB) domain and integrin β2 tail peptide containing pSer756 compared to pSer745. The phosphorylated β2 peptide occupies the canonical ligand binding pocket of Dok1 based on the docked structure of the β2 tail-Dok1 PTB complex. Taken together, our data suggest an alternate phosphorylation switch in β2 integrins that regulates Dok1 binding. This could be important for cells of the immune system and their functions.

  17. Biogeochemistry of metalliferous mine tailings during phytostabilizatio

    NASA Astrophysics Data System (ADS)

    Chorover, J.; Root, R. A.; Hammond, C.; Wang, Y.; Maier, R. M.

    2015-12-01

    In the semi-arid southwest US, legacy mine tailings and the associated metal(loid) contaminants, are prone to wind dispersion and water erosion. Without remediation, tailings can remain barren for decades to centuries, providing a point source of toxic contamination. Successful mitigation of toxins (As, Pb) from fugitive dust is often limited to confinement and stabilization. Capping mine tailings with soil or gravel is an accepted, although expensive, strategy to reduce erosion. Revegetation via assisted direct planting (also known as phytostabilization) has the potential to be a cost-effective and self-sustaining alternative "green-technology" to expensive capping. The impact of phytostabilization, and requisite added organic carbon and irrigation on mechanisms of contaminant mobility is being investigated with concurrent highly-instrumented greenhouse mesocosms and in situ field studies using advanced microbiological tools and synchrotron x-ray based molecular probes. Composted treatments initially neutralized the near surface acid tailings (~2 to ~6.5). However, after 9 mo the mesocosms showed a gradual and eventual decrease back to pH 2. The exception was the root zone of Atriplex lentiformis, which buffered the acidic conditions for 12 months. Rhizosphere microbiota experienced a 5-log increase in the compost-amended compared to control greenhouse mesocosms. Weathering of the primary sulfidic mineral assemblage, indicated by the iron and sulfur speciation, was shown to control the mobility, speciation and bioavailability of both As and Pb via sequestration in (meta)stable neoformed jarosite phases as plumbojarosite and As(V) substituted for sulfate in hydronium jarosite, with important implications for human and environmental health risk management. We conclude that the disequilibrium imposed by phytostabilization results in an increase of heterotrophic biomass that is concurrent with a time series of geochemical transformations, which controls the species

  18. Antineutrophil Cytoplasmic Antibodies Associated With Infective Endocarditis

    PubMed Central

    Langlois, Vincent; Lesourd, Anais; Girszyn, Nicolas; Ménard, Jean-Francois; Levesque, Hervé; Caron, Francois; Marie, Isabelle

    2016-01-01

    Abstract To determine the prevalence of antineutrophil cytoplasmic antibodies (ANCA) in patients with infective endocarditis (IE) in internal medicine; and to compare clinical and biochemical features and outcome between patients exhibiting IE with and without ANCA. Fifty consecutive patients with IE underwent ANCA testing. The medical records of these patients were reviewed. Of the 50 patients with IE, 12 exhibited ANCA (24%). ANCA-positive patients with IE exhibited: longer duration between the onset of first symptoms and IE diagnosis (P = 0.02); and more frequently: weight loss (P = 0.017) and renal impairment (P = 0.08), lower levels of C-reactive protein (P = 0.0009) and serum albumin (P = 0.0032), involvement of both aortic and mitral valves (P = 0.009), and longer hospital stay (P = 0.016). Under multivariate analysis, significant factors for ANCA-associated IE were: longer hospital stay (P = 0.004), lower level of serum albumin (P = 0.02), and multiple valve involvement (P = 0.04). Mortality rate was 25% in ANCA patients; death was because of IE complications in all these patients. Our study identifies a high prevalence of ANCA in unselected patients with IE in internal medicine (24%). Our findings further underscore that ANCA may be associated with a subacute form of IE leading to multiple valve involvement and more frequent renal impairment. Because death was due to IE complications in all patients, our data suggest that aggressive therapy may be required to improve such patients’ outcome. PMID:26817911

  19. Analysis of the Role of the C-Terminal Tail in the Regulation of the Epidermal Growth Factor Receptor.

    PubMed

    Kovacs, Erika; Das, Rahul; Wang, Qi; Collier, Timothy S; Cantor, Aaron; Huang, Yongjian; Wong, Kathryn; Mirza, Amar; Barros, Tiago; Grob, Patricia; Jura, Natalia; Bose, Ron; Kuriyan, John

    2015-09-01

    The ∼230-residue C-terminal tail of the epidermal growth factor receptor (EGFR) is phosphorylated upon activation. We examined whether this phosphorylation is affected by deletions within the tail and whether the two tails in the asymmetric active EGFR dimer are phosphorylated differently. We monitored autophosphorylation in cells using flow cytometry and found that the first ∼80 residues of the tail are inhibitory, as demonstrated previously. The entire ∼80-residue span is important for autoinhibition and needs to be released from both kinases that form the dimer. These results are interpreted in terms of crystal structures of the inactive kinase domain, including two new ones presented here. Deletions in the remaining portion of the tail do not affect autophosphorylation, except for a six-residue segment spanning Tyr 1086 that is critical for activation loop phosphorylation. Phosphorylation of the two tails in the dimer is asymmetric, with the activator tail being phosphorylated somewhat more strongly. Unexpectedly, we found that reconstitution of the transmembrane and cytoplasmic domains of EGFR in vesicles leads to a peculiar phenomenon in which kinase domains appear to be trapped between stacks of lipid bilayers. This artifactual trapping of kinases between membranes enhances an intrinsic functional asymmetry in the two tails in a dimer. PMID:26124280

  20. mRNA poly(A)-tail changes specified by deadenylation broadly reshape translation in Drosophila oocytes and early embryos

    PubMed Central

    Eichhorn, Stephen W; Subtelny, Alexander O; Kronja, Iva; Kwasnieski, Jamie C; Orr-Weaver, Terry L; Bartel, David P

    2016-01-01

    Because maturing oocytes and early embryos lack appreciable transcription, posttranscriptional regulatory processes control their development. To better understand this control, we profiled translational efficiencies and poly(A)-tail lengths throughout Drosophila oocyte maturation and early embryonic development. The correspondence between translational-efficiency changes and tail-length changes indicated that tail-length changes broadly regulate translation until gastrulation, when this coupling disappears. During egg activation, relative changes in poly(A)-tail length, and thus translational efficiency, were largely retained in the absence of cytoplasmic polyadenylation, which indicated that selective poly(A)-tail shortening primarily specifies these changes. Many translational changes depended on PAN GU and Smaug, and these changes were largely attributable to tail-length changes. Our results also revealed the presence of tail-length–independent mechanisms that maintained translation despite tail-length shortening during oocyte maturation, and prevented essentially all translation of bicoid and several other mRNAs before egg activation. In addition to these fundamental insights, our results provide valuable resources for future studies. DOI: http://dx.doi.org/10.7554/eLife.16955.001 PMID:27474798

  1. Analysis of the Role of the C-Terminal Tail in the Regulation of the Epidermal Growth Factor Receptor

    PubMed Central

    Kovacs, Erika; Das, Rahul; Wang, Qi; Collier, Timothy S.; Cantor, Aaron; Huang, Yongjian; Wong, Kathryn; Mirza, Amar; Barros, Tiago; Grob, Patricia; Jura, Natalia; Bose, Ron

    2015-01-01

    The ∼230-residue C-terminal tail of the epidermal growth factor receptor (EGFR) is phosphorylated upon activation. We examined whether this phosphorylation is affected by deletions within the tail and whether the two tails in the asymmetric active EGFR dimer are phosphorylated differently. We monitored autophosphorylation in cells using flow cytometry and found that the first ∼80 residues of the tail are inhibitory, as demonstrated previously. The entire ∼80-residue span is important for autoinhibition and needs to be released from both kinases that form the dimer. These results are interpreted in terms of crystal structures of the inactive kinase domain, including two new ones presented here. Deletions in the remaining portion of the tail do not affect autophosphorylation, except for a six-residue segment spanning Tyr 1086 that is critical for activation loop phosphorylation. Phosphorylation of the two tails in the dimer is asymmetric, with the activator tail being phosphorylated somewhat more strongly. Unexpectedly, we found that reconstitution of the transmembrane and cytoplasmic domains of EGFR in vesicles leads to a peculiar phenomenon in which kinase domains appear to be trapped between stacks of lipid bilayers. This artifactual trapping of kinases between membranes enhances an intrinsic functional asymmetry in the two tails in a dimer. PMID:26124280

  2. Examination of Lipopolysaccharide (O-Antigen) Populations of Thiobacillus ferrooxidans from Two Mine Tailings

    PubMed Central

    Southam, G.; Beveridge, T. J.

    1993-01-01

    Net acid-generating capacities of 39.74 kg of H2SO4 per ton (ca. 0.05 kg/kg) (pH 2.68) for the Lemoine copper mine tailings (closed ca. 8 years ago; located 40 km west of Chibougamau, Quebec, Canada) and 16.07 kg of H2SO4 per ton (ca. 0.02 kg/kg) (pH 3.01) for the Copper Rand tailings (in current use and 50 km distant [east] from those of Lemoine) demonstrate that these sulfide tailings can support populations of acidophilic thiobacilli. Oxidized regions in both tailings environments were readily visible, were extremely acidic (Lemoine, pH 2.36; Copper Rand, pH 3.07), and provided natural isolates for our study. A 10% (wt/vol) oxalic acid treatment, which solubilizes both ferric sulfate and ferric hydroxide precipitates (B. Ramsay, J. Ramsay, M. deTremblay, and C. Chavarie, Geomicrobiol. J. 6:171-177, 1988), enabled the recovery of intact bacterial cells from the tailings material and from liquid synthetic medium for lipopolysaccharide analysis. No viable cells could be cultured after this oxalic acid treatment. Sodium dodecyl sulfate-polyacrylamide gel electro-phoretic profiles of lipopolysaccharides extracted from the Lemoine tailings were complex, indicating a heterogeneous population of Thiobacillus ferrooxidans. Six T. ferrooxidans subspecies as identified by lipopolysaccharide analysis (i.e., lipopolysaccharide chemotypes) were eventually isolated from a total of 112 cultures from the Lemoine tailings. Using the same isolate and lipopolysaccharide typing techniques, we identified only a single lipopolysaccharide chemotype from 20 cultures of T. ferrooxidans isolated from the Copper Rand tailings. This homogeneity of lipopolysaccharide chemotype was much different from what was found for the older Lemoine tailings and may reflect a progressive lipopolysaccharide heterogeneity of Thiobacillus isolates as tailings leach and age. Images PMID:16348925

  3. Geochemical modeling of uranium mill tailings: a case study

    SciTech Connect

    Peterson, S.R.; Felmy, A.R.; Serne, R.J.; Gee, G.W.

    1983-08-01

    Liner failure was not found to be a problem when various acidic tailings solutions leached through liner materials for periods up to 3 y. On the contrary, materials that contained over 30% clay showed a decrease in permeability with time in the laboratory columns. The decreases in permeability noted above are attributed to pore plugging resulting from the precipitation of minerals and solids. This precipitation takes place due to the increase in pH of the tailings solution brought about by the buffering capacity of the soil. Geochemical modeling predicts, and x-ray characterization confirms, that precipitation of solids from solution is occurring in the acidic tailings solution/liner interactions studied. X-ray diffraction identified gypsum and alunite group minerals, such as jarosite, as having precipitated after acidic tailings solutions reacted with clay liners. The geochemical modeling and experimental work described above were used to construct an equilibrium conceptual model consisting of minerals and solid phases. This model was developed to represent a soil column. A computer program was used as a tool to solve the system of mathematical equations imposed by the conceptual chemical model. The combined conceptual model and computer program were used to predict aqueous phase compositions of effluent solutions from permeability cells packed with geologic materials and percolated with uranium mill tailings solutions. An initial conclusion drawn from these studies is that the laboratory experiments and geochemical modeling predictions were capable of simulating field observations. The same mineralogical changes and contaminant reductions observed in the laboratory studies were found at a drained evaporation pond (Lucky Mc in Wyoming) with a 10-year history of acid attack. 24 references, 5 figures 5 tables.

  4. CTP synthase forms cytoophidia in the cytoplasm and nucleus

    SciTech Connect

    Gou, Ke-Mian; Chang, Chia-Chun; Shen, Qing-Ji; Sung, Li-Ying; Liu, Ji-Long

    2014-04-15

    CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. - Highlights: • CTP synthase forms cytoophidia not only in the cytoplasm but also in the nucleus. • Glutamine deprivation and Glutamine analogs promotes cytoophidium formation. • N-cytoophidia exhibit distinct morphology when compared to C-cytoophidia. • Both CTP synthase 1 and CTP synthase 2 form cytoophidia in mammalian cells. • Fusions of cytoophidia occur in the cytoplasm and nucleus.

  5. Single cytoplasmic dynein molecule movements: characterization and comparison with kinesin.

    PubMed Central

    Wang, Z; Khan, S; Sheetz, M P

    1995-01-01

    Cytoplasmic dynein is a major microtubule motor for minus-end directed movements including retrograde axonal transport. To better understand the mechanism by which cytoplasmic dynein converts ATP energy into motility, we have analyzed the nanometer-level displacements of latex beads coated with low numbers of cytoplasmic dynein molecules. Cytoplasmic dynein-coated beads exhibited greater lateral movements among microtubule protofilaments (ave. 5.1 times/microns of displacement) compared with kinesin (ave. 0.9 times/micron). In addition, dynein moved rearward up to 100 nm over several hundred milliseconds, often in correlation with off-axis movements from one protofilament to another. We suggest that single molecules of cytoplasmic dynein move the beads because 1) there is a linear dependence of bead motility on dynein/bead ratio, 2) the binding of beads to microtubules studied by laser tweezers is best fit by a first-order Poisson, and 3) the run length histogram of dynein beads follows a first-order decay. At the cellular level, the greater disorder of cytoplasmic dynein movements may facilitate transport by decreasing the duration of collisions between kinesin and cytoplasmic dynein-powered vesicles. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 6 FIGURE 9 PMID:8580344

  6. Cytoplasmic streaming direction reverses in dividing Paramecium bursaria.

    PubMed

    Sikora, J; Wasik, A; Zajaczkowska, M

    1991-11-29

    Using the interference-contrast videomicroscopy the speed of cytoplasmic streaming was measured during the sequence of division stages in thigmotactically settled specimens of Paramecium bursaria. The speed of cytoplasmic flow gradually decreased during the first stages of binary fission and movement became indistinguishable at stage D(3). Almost at the same time cytoplasm started to move in the opposite direction, pushing or pulling the dividing micronucleus into the prospective posterior daughter cell and eventually stopped at stage D(5)-D(6). Further cell division events proceeded without detectable movement of cytoplasmic components. Cytoplasmic streaming in the normal interphase route was gradually restored in daughter cells about 30-40 min after cell separation. During the whole period of binary fission phagocytosis was arrested. Transportation and participation in the positioning of prospective micronuclei in daughter cells seems to be the main function of cytoplasmic streaming activity in cell division of Paramecium bursaria. The possible relationship between the stages of cytoskeleton transitions and the kinetics of cytoplasmic streaming associated with cell divison is discussed. PMID:23194845

  7. CYTOPLASMIC VACUOLIZATION RESPONSES TO CYTOPATHIC BOVINE VIRAL DIARRHOEA VIRUS

    PubMed Central

    Birk, Alexander V.; Dubovi, Edward J.; Cohen-Gould, Leona; Donis, Ruben; Szeto, Hazel. H.

    2008-01-01

    Bovine Viral Diarrhea Virus (BVDV) is a positive sense, single-stranded RNA virus which exhibits two biotypes in standard cell culture systems. The cytopathic strains of this virus (cpBVDV) induce dramatic cytoplasmic vacuolization in cell cultures, while infection with the non-cytopathic (NCP-BVDV) strains produces no overt changes in the host cells. Our results show that extensive cytoplasmic vacuolization is the earliest morphological change in response to cpBVDV infection in MDBK cells. Cells with extensive vacuolization showed no co-existing chromatin condensation, caspase activation, or loss of membrane integrity. In addition, the caspase inhibitor (zVAD-fmk), although improving cell viability of infected cells from 6.7±2.2% to 18.8±2.2%, did not prevent vacuolization. On the ultrastructural level, the virus-induced cytoplasmic vacuoles are single membrane structures containing organelles and cellular debris, which appear capable of fusing with other vacuoles and engulfing surrounding cytoplasmic materials. LysoTracker Red which marks lysosomes did not stain the virus-induced cytoplasmic vacuoles. In addition, this lysosomal dye could be observed in the cytoplasm of vacuolized cells, suggesting a lysosomal abnormality. Our data demonstrate that cpBVDV induced a novel cell death pathway in MDBK cells that is primarily associated with lysosomal dysfunction and the formation of phagocytic cytoplasmic vacuoles, and this mode of cell death is different from apoptosis and necrosis. PMID:18054406

  8. Mechanism of genotoxicity induced by targeted cytoplasmic irradiation

    PubMed Central

    Hong, M; Xu, A; Zhou, H; Wu, L; Randers-Pehrson, G; Santella, R M; Yu, Z; Hei, T K

    2010-01-01

    Background: Direct damage to DNA is generally accepted as the main initiator of mutation and cancer induced by environmental carcinogens or ionising radiation. However, there is accumulating evidence suggesting that extracellular/extranuclear targets may also have a key role in mediating the genotoxic effects of ionising radiation. As the possibility of a particle traversal through the cytoplasm is much higher than through the nuclei in environmental radiation exposure, the contribution to genotoxic damage from cytoplasmic irradiation should not be ignored in radiation risk estimation. Although targeted cytoplasmic irradiation has been shown to induce mutations in mammalian cells, the precise mechanism(s) underlying the mutagenic process is largely unknown. Methods: A microbeam that can target the cytoplasm of cells with high precision was used to study mechanisms involved in mediating the genotoxic effects in irradiated human–hamster hybrid (AL) cells. Results: Targeted cytoplasmic irradiation induces oxidative DNA damages and reactive nitrogen species (RNS) in AL cells. Lipid peroxidation, as determined by the induction of 4-hydroxynonenal was enhanced in irradiated cells, which could be suppressed by butylated hydroxyl toluene treatment. Moreover, cytoplasmic irradiation of AL cells increased expression of cyclooxygenase-2 (COX-2) and activation of extracellular signal-related kinase (ERK) pathway. Conclusion: We herein proposed a possible signalling pathway involving reactive oxygen/nitrogen species and COX-2 in the cytoplasmic irradiation-induced genotoxicity effect. PMID:20842121

  9. Non-human primate model of amyotrophic lateral sclerosis with cytoplasmic mislocalization of TDP-43

    PubMed Central

    Uchida, Azusa; Sasaguri, Hiroki; Kimura, Nobuyuki; Tajiri, Mio; Ohkubo, Takuya; Ono, Fumiko; Sakaue, Fumika; Kanai, Kazuaki; Hirai, Takashi; Sano, Tatsuhiko; Shibuya, Kazumoto; Kobayashi, Masaki; Yamamoto, Mariko; Yokota, Shigefumi; Kubodera, Takayuki; Tomori, Masaki; Sakaki, Kyohei; Enomoto, Mitsuhiro; Hirai, Yukihiko; Kumagai, Jiro; Yasutomi, Yasuhiro; Mochizuki, Hideki; Kuwabara, Satoshi; Uchihara, Toshiki; Mizusawa, Hidehiro

    2012-01-01

    Amyotrophic lateral sclerosis is a fatal neurodegenerative disease characterized by progressive motoneuron loss. Redistribution of transactive response deoxyribonucleic acid-binding protein 43 from the nucleus to the cytoplasm and the presence of cystatin C-positive Bunina bodies are considered pathological hallmarks of amyotrophic lateral sclerosis, but their significance has not been fully elucidated. Since all reported rodent transgenic models using wild-type transactive response deoxyribonucleic acid-binding protein 43 failed to recapitulate these features, we expected a species difference and aimed to make a non-human primate model of amyotrophic lateral sclerosis. We overexpressed wild-type human transactive response deoxyribonucleic acid-binding protein 43 in spinal cords of cynomolgus monkeys and rats by injecting adeno-associated virus vector into the cervical cord, and examined the phenotype using behavioural, electrophysiological, neuropathological and biochemical analyses. These monkeys developed progressive motor weakness and muscle atrophy with fasciculation in distal hand muscles first. They also showed regional cytoplasmic transactive response deoxyribonucleic acid-binding protein 43 mislocalization with loss of nuclear transactive response deoxyribonucleic acid-binding protein 43 staining in the lateral nuclear group of spinal cord innervating distal hand muscles and cystatin C-positive cytoplasmic aggregates, reminiscent of the spinal cord pathology of patients with amyotrophic lateral sclerosis. Transactive response deoxyribonucleic acid-binding protein 43 mislocalization was an early or presymptomatic event and was later associated with neuron loss. These findings suggest that the transactive response deoxyribonucleic acid-binding protein 43 mislocalization leads to α-motoneuron degeneration. Furthermore, truncation of transactive response deoxyribonucleic acid-binding protein 43 was not a prerequisite for motoneuronal degeneration, and

  10. The C-terminal tail of protein kinase D2 and protein kinase D3 regulates their intracellular distribution

    SciTech Connect

    Papazyan, Romeo; Rozengurt, Enrique; Rey, Osvaldo . E-mail: orey@mednet.ucla.edu

    2006-04-14

    We generated a set of GFP-tagged chimeras between protein kinase D2 (PKD2) and protein kinase D3 (PKD3) to examine in live cells the contribution of their C-terminal region to their intracellular localization. We found that the catalytic domain of PKD2 and PKD3 can localize to the nucleus when expressed without other kinase domains. However, when the C-terminal tail of PKD2 was added to its catalytic domain, the nuclear localization of the resulting protein was inhibited. In contrast, the nuclear localization of the CD of PKD3 was not inhibited by its C-terminal tail. Furthermore, the exchange of the C-terminal tail of PKD2 and PKD3 in the full-length proteins was sufficient to exchange their intracellular localization. Collectively, these data demonstrate that the short C-terminal tail of these kinases plays a critical role in determining their cytoplasmic/nuclear localization.

  11. Spectral induced polarization (SIP) response of mine tailings.

    PubMed

    Placencia-Gómez, Edmundo; Parviainen, Annika; Slater, Lee; Leveinen, Jussi

    2015-02-01

    Mine tailings impoundments are a source of leachates known as acid mine drainage (AMD) which can pose a contamination risk for surrounding surface and groundwater. Methodologies which can help management of this environmental issue are needed. We carried out a laboratory study of the spectral induced polarization (SIP) response of tailings from the Haveri Au-Cu mine, SW Finland. The primary objectives were, (1) to determine possible correlations between SIP parameters and textural properties associated with oxidative-weathering mechanisms, mineralogical composition and metallic content, and (2) to evaluate the effects of the pore water chemistry on SIP parameters associated with redox-inactive and redox-active electrolytes varying in molar concentration, conductivity and pH. The Haveri tailings exhibit well defined relaxation spectra between 100 and 10,000Hz. The relaxation magnitudes are governed by the in-situ oxidative-weathering conditions on sulphide mineral surfaces contained in the tailings, and decrease with the oxidation degree. The oxidation-driven textural variation in the tailings results in changes to the frequency peak of the phase angle, the imaginary conductivity and chargeability, when plotted versus the pore water conductivity. In contrast, the real and the formation electrical conductivity components show a single linear dependence on the pore water conductivity. The increase of the pore water conductivity (dominated by the increase of ions concentration in solution) along with a transition to acidic conditions shifts the polarization peak towards higher frequencies. These findings show the unique sensitivity of the SIP method to potentially discriminate AMD discharges from reactive oxidation zones in tailings, suggesting a significant advantage for monitoring threatened aquifers. PMID:25528133

  12. Spectral induced polarization (SIP) response of mine tailings

    NASA Astrophysics Data System (ADS)

    Placencia-Gómez, Edmundo; Parviainen, Annika; Slater, Lee; Leveinen, Jussi

    2015-02-01

    Mine tailings impoundments are a source of leachates known as acid mine drainage (AMD) which can pose a contamination risk for surrounding surface and groundwater. Methodologies which can help management of this environmental issue are needed. We carried out a laboratory study of the spectral induced polarization (SIP) response of tailings from the Haveri Au-Cu mine, SW Finland. The primary objectives were, (1) to determine possible correlations between SIP parameters and textural properties associated with oxidative-weathering mechanisms, mineralogical composition and metallic content, and (2) to evaluate the effects of the pore water chemistry on SIP parameters associated with redox-inactive and redox-active electrolytes varying in molar concentration, conductivity and pH. The Haveri tailings exhibit well defined relaxation spectra between 100 and 10,000 Hz. The relaxation magnitudes are governed by the in-situ oxidative-weathering conditions on sulphide mineral surfaces contained in the tailings, and decrease with the oxidation degree. The oxidation-driven textural variation in the tailings results in changes to the frequency peak of the phase angle, the imaginary conductivity and chargeability, when plotted versus the pore water conductivity. In contrast, the real and the formation electrical conductivity components show a single linear dependence on the pore water conductivity. The increase of the pore water conductivity (dominated by the increase of ions concentration in solution) along with a transition to acidic conditions shifts the polarization peak towards higher frequencies. These findings show the unique sensitivity of the SIP method to potentially discriminate AMD discharges from reactive oxidation zones in tailings, suggesting a significant advantage for monitoring threatened aquifers.

  13. Magnetospheric Substorms and Tail Dynamics

    NASA Technical Reports Server (NTRS)

    Hughes, W. Jeffrey

    1998-01-01

    This grant funded several studies of magnetospheric substorms and their effect on the dynamics of the earth's geomagnetic tail. We completed an extensive study of plasmoids, plasma/magnetic field structures that travel rapidly down the tail, using data from the ISEE 3 and IMP 8 spacecraft. This study formed the PhD thesis of Mark Moldwin. We found that magnetically plasmoids are better described as flux-ropes (twisted magnetic flux tubes) rather than plasma bubbles, as had been generally regarded up to that point (Moldwin and Hughes, 1990; 1991). We published several examples of plasmoids observed first in the near tail by IMP 8 and later in the distant tail by ISEE 3, confirming their velocities down tail. We showed how the passage of plasmoids distorts the plasma sheet. We completed the first extensive statistical survey of plasmoids that showed how plasmoids evolve as they move down tail from their formation around 30 RE to ISEE 3 apogee at 240 RE. We established a one-to-one correspondence between the observation of plasmoids in the distant tail and substorm onsets at earth or in the near tail. And we showed that there is a class of plasmoid-like structures that move slowly earthward, especially following weak substorms during northward IMF. Collectively this work constituted the most extensive study of plasmoids prior to the work that has now been done with the GEOTAIL spacecraft. Following our work on plasmoids, we turned our attention to signatures of substorm onset observed in the inner magnetosphere near geosynchronous orbit, especially signatures observed by the CRRES satellite. Using data from the magnetometer, electric field probe, plasma wave instrument, and low energy plasma instrument on CRRES we were able to better document substorm onsets in the inner magnetosphere than had been possible previously. Detailed calculation of the Poynting flux showed energy exchange between the magnetosphere and ionosphere, and a short burst of tailward convective

  14. Quality Control of a Cytoplasmic Protein Complex

    PubMed Central

    Scazzari, Mario; Amm, Ingo; Wolf, Dieter H.

    2015-01-01

    For the assembly of protein complexes in the cell, the presence of stoichiometric amounts of the respective protein subunits is of utmost importance. A surplus of any of the subunits may trigger unspecific and harmful protein interactions and has to be avoided. A stoichiometric amount of subunits must finally be reached via transcriptional, translational, and/or post-translational regulation. Synthesis of saturated 16 and 18 carbon fatty acids is carried out by fatty acid synthase: in yeast Saccharomyces cerevisiae, a 2.6-MDa molecular mass assembly containing six protomers each of two different subunits, Fas1 (β) and Fas2 (α). The (α)6(β)6 complex carries six copies of all eight enzymatic activities required for fatty acid synthesis. The FAS1 and FAS2 genes in yeast are unlinked and map on two different chromosomes. Here we study the fate of the α-subunit of the complex, Fas2, when its partner, the β-subunit Fas1, is absent. Individual subunits of fatty acid synthase are proteolytically degraded when the respective partner is missing. Elimination of Fas2 is achieved by the proteasome. Here we show that a ubiquitin transfer machinery is required for Fas2 elimination. The major ubiquitin ligase targeting the superfluous Fas2 subunit to the proteasome is Ubr1. The ubiquitin-conjugating enzymes Ubc2 and Ubc4 assist the degradation process. The AAA-ATPase Cdc48 and the Hsp70 chaperone Ssa1 are crucially involved in the elimination of Fas2. PMID:25564609

  15. Determination of the reaction rate coefficient of sulphide mine tailings deposited under water.

    PubMed

    Awoh, Akué Sylvette; Mbonimpa, Mamert; Bussière, Bruno

    2013-10-15

    The efficiency of a water cover to limit dissolved oxygen (DO) availability to underlying acid-generating mine tailings can be assessed by calculating the DO flux at the tailings-water interface. Fick's equations, which are generally used to calculate this flux, require knowing the effective DO diffusion coefficient (Dw) and the reaction (consumption) rate coefficient (Kr) of the tailings, or the DO concentration profile. Whereas Dw can be accurately estimated, few studies have measured the parameter Kr for submerged sulphide tailings. The objective of this study was to determine Kr for underwater sulphide tailings in a laboratory experiment. Samples of sulphide mine tailings (an approximately 6 cm layer) were placed in a cell under a water cover (approximately 2 cm) maintained at constant DO concentration. Two tailings were studied: TA1 with high sulphide content (83% pyrite) and TA2 with low sulphide content (2.8% pyrite). DO concentration was measured with a microelectrode at various depths above and below the tailings-water interface at 1 mm intervals. Results indicate that steady-state condition was rapidly attained. As expected, a diffusive boundary layer (DBL) was observed in all cases. An iterative back-calculation process using the numerical code POLLUTEv6 and taking the DBL into account provided the Kr values used to match calculated and experimental concentration profiles. Kr obtained for tailings TA1 and TA2 was about 80 d(-1) and 6.5 d(-1), respectively. For comparison purposes, Kr obtained from cell tests on tailings TA1 was lower than Kr calculated from the sulphate production rate obtained from shake-flask tests. Steady-state DO flux at the water-tailings interface was then calculated with POLLUTEv6 using tailings characteristics Dw and Kr. For the tested conditions, DO flux ranged from 608 to 758 mg O2/m(2)/d for tailings TA1 and from 177 to 221 mg O2/m(2)/d for tailings TA2. The impact of placing a protective layer of inert material over

  16. Nuclear Proteins Hijacked by Mammalian Cytoplasmic Plus Strand RNA Viruses

    PubMed Central

    Lloyd, Richard E.

    2015-01-01

    Plus strand RNA viruses that replicate in the cytoplasm face challenges in supporting the numerous biosynthetic functions required for replication and propagation. Most of these viruses are genetically simple and rely heavily on co-opting cellular proteins, particularly cellular RNA-binding proteins, into new roles for support of virus infection at the level of virus-specific translation, and building RNA replication complexes. In the course of infectious cycles many nuclear-cytoplasmic shuttling proteins of mostly nuclear distribution are detained in the cytoplasm by viruses and re-purposed for their own gain. Many mammalian viruses hijack a common group of the same factors. This review summarizes recent gains in our knowledge of how cytoplasmic RNA viruses use these co-opted host nuclear factors in new functional roles supporting virus translation and virus RNA replication and common themes employed between different virus groups. PMID:25818028

  17. CYTOPLASMIC MICROTUBULAR DYNAMIC AND CHROMATIN ORGANIZATION DURING MAMMALIAN OOCYTE MATURATION

    EPA Science Inventory

    Coordinated alterations in oocyte chromosome and microtubule disposition occur during oogenesis and oocyte maturation in the mammal. imely transitions in meiotic spindle and cytoplasmic microtubules, due to modifications in both the assembly competence of the tubulin pool and nuc...

  18. Stabilization and Degradation Mechanisms of Cytoplasmic Ataxin-1

    PubMed Central

    Kohiyama, Mayumi F.; Lagalwar, Sarita

    2015-01-01

    Aggregation-prone proteins in neurodegenerative disease disrupt cellular protein stabilization and degradation pathways. The neurodegenerative disease spinocerebellar ataxia type 1 (SCA1) is caused by a coding polyglutamine expansion in the Ataxin-1 gene (ATXN1), which gives rise to the aggregation-prone mutant form of ATXN1 protein. Cerebellar Purkinje neurons, preferentially vulnerable in SCA1, produce ATXN1 protein in both cytoplasmic and nuclear compartments. Cytoplasmic stabilization of ATXN1 by phosphorylation and 14-3-3-mediated mechanisms ultimately drive translocation of the protein to the nucleus where aggregation may occur. However, experimental inhibition of phosphorylation and 14-3-3 binding results in rapid degradation of ATXN1, thus preventing nuclear translocation and cellular toxicity. The exact mechanism of cytoplasmic ATXN1 degradation is currently unknown; further investigation of degradation may provide future therapeutic targets. This review examines the present understanding of cytoplasmic ATXN1 stabilization and potential degradation mechanisms during normal and pathogenic states. PMID:27168726

  19. Proton flows across the plasma membrane in microperforated characean internodes: tonoplast injury and involvement of cytoplasmic streaming.

    PubMed

    Bulychev, Alexander A; Komarova, Anna V

    2014-11-01

    Microperforation of characean cell wall with a glass micropipette in the absence of the tonoplast impalement was found to cause rapid alkalinization of the apoplast by 2-3 pH units, which may rigidify the cell wall structure, thus protecting the cell from further injury. A similar but a deeper insertion of a microneedle, associated with piercing the tonoplast and with an action potential generation, led to a considerable delay in the apoplast alkalinization without affecting the amplitude of the eventual increase in pH. The retardation by the mechanically elicited action potential of the incision-mediated pH transients in the apoplast contrasted sharply to the enhancement of these pH transients by the action potential triggered electrically before the microperforation. Hence, the delay of the apoplast alkalinization was not related to basic ionic mechanisms of plant action potentials. Measurements of the vacuolar pH after mechanical elicitation of an action potential indicate that the tonoplast piercing was accompanied by leakage of protons from the vacuole into the cytoplasm, which may strongly acidify the cytoplasm around the wounded area, thus collapsing the driving force for H(+) influx from the medium into the cytoplasm. The lag period preceding the onset of external alkalinization was found linearly related to the duration of temporal cessation of cytoplasmic streaming. The results suggest that the delayed alkalinization of the apoplast in the region of tonoplast wounding reflects the localized recovery of the proton motive force across the plasmalemma during replacement of the acidic cytoplasm with fresh portions of unimpaired cytoplasm upon restoration of cytoplasmic streaming. PMID:24788928

  20. Plant growth-promoting bacteria for phytostabilization of mine tailings.

    PubMed

    Grandlic, Christopher J; Mendez, Monica O; Chorover, Jon; Machado, Blenda; Maier, Raina M

    2008-03-15

    Eolian dispersion of mine tailings in arid and semiarid environments is an emerging global issue for which economical remediation alternatives are needed. Phytostabilization, the revegetation of these sites with native plants, is one such alternative. Revegetation often requires the addition of bulky amendments such as compost which greatly increases cost. We report the use of plant growth-promoting bacteria (PGPB) to enhance the revegetation of mine tailings and minimize the need for compost amendment. Twenty promising PGPB isolates were used as seed inoculants in a series of greenhouse studies to examine revegetation of an extremely acidic, high metal contenttailings sample previously shown to require 15% compost amendment for normal plant growth. Several isolates significantly enhanced growth of two native species, quailbush and buffalo grass, in tailings. In this study, PGPB/compost outcomes were plant specific; for quailbush, PGPB were most effective in combination with 10% compost addition while for buffalo grass, PGPB enhanced growth in the complete absence of compost. Results indicate that selected PGPB can improve plant establishment and reduce the need for compost amendment. Further, PGPB activities necessary for aiding plant growth in mine tailings likely include tolerance to acidic pH and metals. PMID:18409640

  1. Population replacement in Culex fatigans by means of cytoplasmic incompatibility

    PubMed Central

    Curtis, C. F.

    1976-01-01

    Three experiments were carried out in field cages to test the principle of “transport” of a desirable gene or chromosome into a wild Culex fatigans population as a result of the sterility in cross-matings associated with cytoplasmic incompatibility. Cycling populations of Delhi origin were established in the cages and daily releases were made of the IS31B strain, which has Paris cytoplasm and carries a male-linked translocation. It was shown that, if sufficient releases were made to establish a majority of the Paris cytoplasmic type, complete replacement by this cytoplasmic type subsequently occurred. However, as a result of partial compatibility of males of the Delhi population with Paris females, “recombinant” males with Paris cytoplasm and no translocation were produced. In an experiment in which a continuous low rate of “immigration” of a strain of Delhi origin was simulated, a gradual increase of the Paris cytoplasm nontranslocated type occurred, and renewed IS31B releases were necessary after 5 months to restore the predominance of this type. The results are compared with computer predictions and discussed in relation to the transport of genes for filaria refractoriness or chromosome translocations into wild populations. PMID:1085660

  2. Local changes in lipid environment of TCR microclusters regulate membrane binding by the CD3ε cytoplasmic domain

    PubMed Central

    Schubert, David A.; Gordo, Susana; Chu, H. Hamlet

    2012-01-01

    The CD3ε and ζ cytoplasmic domains of the T cell receptor bind to the inner leaflet of the plasma membrane (PM), and a previous nuclear magnetic resonance structure showed that both tyrosines of the CD3ε immunoreceptor tyrosine-based activation motif partition into the bilayer. Electrostatic interactions between acidic phospholipids and clusters of basic CD3ε residues were previously shown to be essential for CD3ε and ζ membrane binding. Phosphatidylserine (PS) is the most abundant negatively charged lipid on the inner leaflet of the PM and makes a major contribution to membrane binding by the CD3ε cytoplasmic domain. Here, we show that TCR triggering by peptide–MHC complexes induces dissociation of the CD3ε cytoplasmic domain from the plasma membrane. Release of the CD3ε cytoplasmic domain from the membrane is accompanied by a substantial focal reduction in negative charge and available PS in TCR microclusters. These changes in the lipid composition of TCR microclusters even occur when TCR signaling is blocked with a Src kinase inhibitor. Local changes in the lipid composition of TCR microclusters thus render the CD3ε cytoplasmic domain accessible during early stages of T cell activation. PMID:23166358

  3. Lobster Tail Ice Formation on Aerosurface

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Glace Ice formation commonly refered to as 'Lobster Tail' by scientists and engineers, is caused to form on the leading edge of a aircraft tail section in the icing research tunnel at the NASA Glenn Research Center, Cleveland, Ohio.

  4. Shifts in microbial community composition and function in the acidification of a lead/zinc mine tailings.

    PubMed

    Chen, Lin-Xing; Li, Jin-Tian; Chen, Ya-Ting; Huang, Li-Nan; Hua, Zheng-Shuang; Hu, Min; Shu, Wen-Sheng

    2013-09-01

    In an attempt to link the microbial community composition and function in mine tailings to the generation of acid mine drainage, we simultaneously explored the geochemistry and microbiology of six tailings collected from a lead/zinc mine, i.e. primary tailings (T1), slightly acidic tailings (T2), extremely acidic tailings (T3, T4 and T5) and orange-coloured oxidized tailings (T6). Geochemical results showed that the six tailings (from T1 to T6) likely represented sequential stages of the acidification process of the mine tailings. 16S rRNA pyrosequencing revealed a contrasting microbial composition between the six tailings: Proteobacteria-related sequences dominated T1-T3 with relative abundance ranging from 56 to 93%, whereas Ferroplasma-related sequences dominated T4-T6 with relative abundance ranging from 28 to 58%. Furthermore, metagenomic analysis of the microbial communities of T2 and T6 indicated that the genes encoding key enzymes for microbial carbon fixation, nitrogen fixation and sulfur oxidation in T2 were largely from Thiobacillus and Acidithiobacillus, Methylococcus capsulatus, and Thiobacillus denitrificans respectively; while those in T6 were mostly identified in Acidithiobacillus and Leptospirillum, Acidithiobacillus and Leptospirillum, and Acidithiobacillus respectively. The microbial communities in T2 and T6 harboured more genes suggesting diverse metabolic capacities for sulfur oxidation/heavy metal detoxification and tolerating low pH respectively. PMID:23574280

  5. In vitro synthesis of cellulose II from a cytoplasmic membrane fraction of Acetobacter xylinum

    SciTech Connect

    Bureau, T.E.; Brown, R.M. Jr.

    1987-10-01

    The cytoplasmic and outer membranes of Acetobacter xylinum were isolated by discontinuous sucrose density ultracentrifugation. Both lysozyme and trypsin were required for efficient crude membrane separation. Primary dehydrogenases and NADH oxidase were used as cytoplasmic membrane markers, and 2-keto-3-deoxyoctulosonic acid was used to identify the outer membranes. Cellulose synthetase activity was assayed as the conversion of radioactivity from UDP-(/sup 14/C)glucose into an alkali-insoluble ..beta..-1,4-D-(/sup 14/C)glucan. This activity was predominantly found in the cytoplasmic membrane. The cellulose nature of the product was demonstrated by (i) enzymatic hydrolysis followed by TLC, (ii) methylation analysis followed by TLC, and (iii) GC/MS. Further, the weight-average and number-average degree of polymerization of the in vitro product, determined by high-performance gel permeation chromatography, were 4820 and 5270, respectively. In addition, x-ray diffraction analysis indicated that the in vitro product is cellulose II, which is in contrast to the in vivo product--namely, cellulose I.

  6. In vitro synthesis of cellulose II from a cytoplasmic membrane fraction of Acetobacter xylinum

    PubMed Central

    Bureau, Thomas E.; Brown, R. Malcolm

    1987-01-01

    The cytoplasmic and outer membranes of Acetobacter xylinum (ATCC 53582) were isolated by discontinuous sucrose density ultracentrifugation. Both lysozyme (EC 3.2.1.17) and trypsin (EC 3.4.21.4) were required for efficient crude membrane separation. Primary dehydrogenases and NADH oxidase were used as cytoplasmic membrane markers, and 2-keto-3-deoxyoctulosonic acid was used to identify the outer membranes. Cellulose synthetase (UDP-glucose:1,4-β-D-glucan 4-β-D-glucosyltransferase; EC 2.4.1.12) activity was assayed as the conversion of radioactivity from UDP-[14C]glucose into an alkali-insoluble β-1,4-D-[14C]glucan. This activity was predominantly found in the cytoplasmic membrane. The cellulose nature of the product was demonstrated by (i) enzymatic hydrolysis followed by TLC, (ii) methylation analysis followed by TLC, and (iii) GC/MS. Further, the weight-average and number-average degree of polymerization of the in vitro product, determined by high-performance gel permeation chromatography, were 4820 and 5270, respectively. In addition, x-ray diffraction analysis indicated that the in vitro product is cellulose II, which is in contrast to the in vivo product—namely, cellulose I. Images PMID:16593877

  7. A cytoplasmic polyhedrosis virus isolated from the pine processionary caterpillar, Thaumetopoea pityocampa.

    PubMed

    Ince, Ikbal Agah; Demir, Ismail; Demirbag, Zihni; Nalcacioglu, Remziye

    2007-04-01

    A cytoplasmic polyhedrosis virus (CPV) was isolated from the larvae of Thaumetopoea pityocampa and shown to cause an infection of midgut cells. This viral infection revealed several important diagnostic symptoms, including discoloration of the posterior midgut, reduced feeding, and extended development time of the larvae. The virus infection is lethal to Thaumetopoea pityocampa, and with the increasing doses kills the larvae within 4-5 days post infection. Electron microscopy studies showed typical cytoplasmic polyhedral inclusion bodies that are icosahedral, and ranged from 2.4 to 5.3 microm in diameter. Electrophoretic analysis of the RNA genome showed that the virus has a genome composed of 10 equimolar RNA segments with the sizes of 3,907, 3,716, 3,628, 3,249, 2,726, 1,914, 1,815, 1,256, 1,058, and 899 bp, respectively. Based on morphology and nucleic acid analysis, this virus was named Thaumetopoea pityocampa cytoplasmic polyhedrosis virus (TpCPV), and belongs to the genus Cypovirus, family Reoviridae. PMID:18051275

  8. Storm-water hydrograph separation of run off from a mine-tailings impoundment formed by thickened tailings discharge at Kidd Creek, Timmins, Ontario

    NASA Astrophysics Data System (ADS)

    Al, Tom A.; Blowes, David W.

    1996-05-01

    The Kidd Creek CuZn sulphide mine is located near Timmins, Ontario. Mill tailings are thickened and deposited as a thickened slurry in a circular, conical-shaped pile with an area of approximately 1200 ha. Deposition of tailings as a thickened slurry results in a relatively uniform grain-size distribution and hydraulic conductivity, and a thick tension-saturated zone above the water table. The tailings are drained by numerous small, ephemeral stream channels, which have developed in a radial pattern. During storms, water from these streams collects in catchment ponds where it is held before treatment. The contribution of tailings pore water to the run off is of interest because of the potential for discharge of pore water containing high concentrations of Fe(II)-acidity, metals and SO 4 to the stream. Hydraulic head measurements, measurements of water-table elevation and groundwater flow modelling were conducted to determine the mechanisms responsible for tailings pore water entering the surface streams. Chemical hydrograph separation of storm run off in one of these streams, during three rainfall events, using Na and Cl as conservative tracers, indicates that the integrated tailings pore water fraction makes up between less than 1 % and 20% of the total hydrograph. This range is less than the maximum fraction of tailings pore water of 22-65% reported for run off from a conventional tailings deposit. At this site, preferential flow through permeable fractures may be the dominant mechanism causing discharge of tailings pore water to storm run off. Estimates of the mass of Fe(II) that discharges to the surface run off from the pore water range up to 2800 mg s -1 during a moderate intensity, long duration rainfall event. The greatest potential for discharge of significant masses of solutes derived from the pore water exists during long duration rainfall events, when the water table rises to the surface over large areas of the tailings impoundment.

  9. Monitoring pool-tail fines

    NASA Astrophysics Data System (ADS)

    Bunte, K.; Potyondy, J. P.; Abt, S. R.; Swingle, K. W.

    2010-12-01

    Fine sediment < 2 and < 6 mm deposited in pool-tail areas of mountain streams is often measured to monitor changes in the supply of fines (e.g., by dam removal, bank erosion, or watershed effects including fires and road building) or to assess the status and trend of aquatic ecosystems. Grid counts, pebble counts, and volumetric bedmaterial samples are typically used to quantify pool-tail fines. Grid-count results exhibit a high degree of variability not only among streams and among operators, but also among crews performing a nearly identical procedure (Roper et al. 2010). Variability is even larger when diverse methods are employed, each of which quantifies fines in a different way: grid counts visually count surface fines on small patches within the pool-tail area, pebble counts pick up and tally surface particles along (riffle) transects, and volumetric samples sieve out fines from small-scale bulk samples; and even when delimited to pool-tail areas, individual methods focus on different sampling locales. Two main questions were analyzed: 1) Do pool-tail fines exhibit patterns of spatial variability and are some grid count schemes more likely to provide accurate results than others. 2) How and why does the percentage of fines vary among grid counts, pebble counts, and volumetric samples. In a field study, grids were placed at 7 locales in two rows across the wetted width of 10 pool tails in a 14-m wide 3rd order coarse gravel-bed mountain stream with <4% sand and <8% < 6 mm. Several pebble count transects were placed across each pool-tail area, and three volumetric samples were collected in each of three pool tails. Pebble and grid counts both indicated a fining trend towards one or both banks, sometimes interrupted by a secondary peak of fines within the central half of the wetted width. Among the five sampling schemes tested, grid counts covering the wetted width with 7 locales produced the highest accuracy and the least variability among the pools of the

  10. 14 CFR 29.1565 - Tail rotor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tail rotor. 29.1565 Section 29.1565 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS....1565 Tail rotor. Each tail rotor must be marked so that its disc is conspicuous under normal...

  11. 14 CFR 27.1565 - Tail rotor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tail rotor. 27.1565 Section 27.1565 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... Tail rotor. Each tail rotor must be marked so that its disc is conspicuous under normal daylight...

  12. Geochemical modeling of cyanide in tailing dam gold processing plant

    NASA Astrophysics Data System (ADS)

    Khodadadi, Ahmad; Monjezi, M.; Mehrpouya, H.; Dehghani, H.

    2009-09-01

    This research is aimed at investigating possible neutralization of cyanide in tailing dam of Muteh gold processing plant in Isfahan, Iran at various conditions such as pH and temperature using USEPA Visual MINTEQ geochemical model simulation. The model is based on geochemical equilibrium which uses the simultaneous solution of the non-linear mass action expressions and linear mass balance relationships to formulate and solve the multiple-component chemical equilibrium problems. In this study the concentration of aqueous species in tailing dam as an aqueous, solid and gaseous were used as input in the model. Temperature and pH variation were simulated. The results of the model indicated that cyanide may be complexes in 10 < pH < 5. In other pH values complexation is not important. The results also indicated that cyanide reduction mechanism in acidic pH and temperature above 30°C is due to cyanide acid formation which is vaporized.

  13. Fluoride enhances transfection activity of carbonate apatite by increasing cytoplasmic stability of plasmid DNA

    SciTech Connect

    Chowdhury, E.H.

    2011-06-17

    Highlights: {yields} Cytoplasmic stability of plasmid DNA is enhanced by fluoride incorporation into carbonate apatite carrier. {yields} Fluoridated carbonate apatite promotes a robust increase in transgene expression. {yields} Controlled dissolution of fluoridated carbonate apatite in endosomal acidic environment might buffer the endosomes and prevent degradation of the released DNA. -- Abstract: Intracellular delivery of a functional gene or a nucleic acid sequence to specifically knockdown a harmful gene is a potential approach to precisely treat a critical human disease. The intensive efforts in the last few decades led to the development of a number of viral and non-viral synthetic vectors. However, an ideal delivery tool in terms of the safety and efficacy has yet to be established. Recently, we have developed pH-sensing inorganic nanocrystals of carbonate apatite for efficient and cell-targeted delivery of gene and gene-silencing RNA. Here we show that addition of very low level of fluoride to the particle-forming medium facilitates a robust increase in transgene expression following post-incubation of the particles with HeLa cells. Confocal microscopic observation and Southern blotting prove the cytoplasmic existence of plasmid DNA delivered by likely formed fluoridated carbonate apatite particles while degradation of plasmid DNA presumably by cytoplasmic nucleases was noticed following delivery with apatite particles alone. The beneficial role of fluoride in enhancing carbonate apatite-mediated gene expression might be due to the buffering potential of generated fluoridated apatite in endosomal acidic environment, thereby increasing the half-life of delivered plasmid DNA.

  14. Formation of a cytoplasmic salt bridge network in the matrix state is a fundamental step in the transport mechanism of the mitochondrial ADP/ATP carrier

    PubMed Central

    King, Martin S.; Kerr, Matthew; Crichton, Paul G.; Springett, Roger; Kunji, Edmund R.S.

    2016-01-01

    Mitochondrial ADP/ATP carriers catalyze the equimolar exchange of ADP and ATP across the mitochondrial inner membrane. Structurally, they consist of three homologous domains with a single substrate binding site. They alternate between a cytoplasmic and matrix state in which the binding site is accessible to these compartments for binding of ADP or ATP. It has been proposed that cycling between states occurs by disruption and formation of a matrix and cytoplasmic salt bridge network in an alternating way, but formation of the latter has not been shown experimentally. Here, we show that state-dependent formation of the cytoplasmic salt bridge network can be demonstrated by measuring the effect of mutations on the thermal stability of detergent-solubilized carriers locked in a specific state. For this purpose, mutations were made to increase or decrease the overall interaction energy of the cytoplasmic network. When locked in the cytoplasmic state by the inhibitor carboxyatractyloside, the thermostabilities of the mutant and wild-type carriers were similar, but when locked in the matrix state by the inhibitor bongkrekic acid, they correlated with the predicted interaction energy of the cytoplasmic network, demonstrating its formation. Changing the interaction energy of the cytoplasmic network also had a profound effect on the kinetics of transport, indicating that formation of the network is a key step in the transport cycle. These results are consistent with a unique alternating access mechanism that involves the simultaneous rotation of the three domains around a central translocation pathway. PMID:26453935

  15. Formation of a cytoplasmic salt bridge network in the matrix state is a fundamental step in the transport mechanism of the mitochondrial ADP/ATP carrier.

    PubMed

    King, Martin S; Kerr, Matthew; Crichton, Paul G; Springett, Roger; Kunji, Edmund R S

    2016-01-01

    Mitochondrial ADP/ATP carriers catalyze the equimolar exchange of ADP and ATP across the mitochondrial inner membrane. Structurally, they consist of three homologous domains with a single substrate binding site. They alternate between a cytoplasmic and matrix state in which the binding site is accessible to these compartments for binding of ADP or ATP. It has been proposed that cycling between states occurs by disruption and formation of a matrix and cytoplasmic salt bridge network in an alternating way, but formation of the latter has not been shown experimentally. Here, we show that state-dependent formation of the cytoplasmic salt bridge network can be demonstrated by measuring the effect of mutations on the thermal stability of detergent-solubilized carriers locked in a specific state. For this purpose, mutations were made to increase or decrease the overall interaction energy of the cytoplasmic network. When locked in the cytoplasmic state by the inhibitor carboxyatractyloside, the thermostabilities of the mutant and wild-type carriers were similar, but when locked in the matrix state by the inhibitor bongkrekic acid, they correlated with the predicted interaction energy of the cytoplasmic network, demonstrating its formation. Changing the interaction energy of the cytoplasmic network also had a profound effect on the kinetics of transport, indicating that formation of the network is a key step in the transport cycle. These results are consistent with a unique alternating access mechanism that involves the simultaneous rotation of the three domains around a central translocation pathway. PMID:26453935

  16. Cytoplasmic translocation, aggregation, and cleavage of TDP-43 by enteroviral proteases modulate viral pathogenesis.

    PubMed

    Fung, G; Shi, J; Deng, H; Hou, J; Wang, C; Hong, A; Zhang, J; Jia, W; Luo, H

    2015-12-01

    We have previously demonstrated that infection by coxsackievirus B3 (CVB3), a positive-stranded RNA enterovirus, results in the accumulation of insoluble ubiquitin-protein aggregates, which resembles the common feature of neurodegenerative diseases. The importance of protein aggregation in viral pathogenesis has been recognized; however, the underlying regulatory mechanisms remain ill-defined. Transactive response DNA-binding protein-43 (TDP-43) is an RNA-binding protein that has an essential role in regulating RNA metabolism at multiple levels. Cleavage and cytoplasmic aggregation of TDP-43 serves as a major molecular marker for amyotrophic lateral sclerosis and frontotemporal lobar degeneration and contributes significantly to disease progression. In this study, we reported that TDP-43 is translocated from the nucleus to the cytoplasm during CVB3 infection through the activity of viral protease 2A, followed by the cleavage mediated by viral protease 3C. Cytoplasmic translocation of TDP-43 is accompanied by reduced solubility and increased formation of protein aggregates. The cleavage takes place at amino-acid 327 between glutamine and alanine, resulting in the generation of an N- and C-terminal cleavage fragment of ~35 and ~8 kDa, respectively. The C-terminal product of TDP-43 is unstable and quickly degraded through the proteasome degradation pathway, whereas the N-terminal truncation of TDP-43 acts as a dominant-negative mutant that inhibits the function of native TDP-43 in alternative RNA splicing. Lastly, we demonstrated that knockdown of TDP-43 results in an increase in viral titers, suggesting a protective role for TDP-43 in CVB3 infection. Taken together, our findings suggest a novel model by which cytoplasmic redistribution and cleavage of TDP-43 as a consequence of CVB3 infection disrupts the solubility and transcriptional activity of TDP-43. Our results also reveal a mechanism evolved by enteroviruses to support efficient viral infection. PMID

  17. Human autoantibodies to diacyl-phosphatidylethanolamine recognize a specific set of discrete cytoplasmic domains

    PubMed Central

    Laurino, C C F C; Fritzler, M J; Mortara, R A; Silva, N P; Almeida, I C; Andrade, L E C

    2006-01-01

    The aim of this study was to characterize a novel human autoantibody–autoantigen system represented as cytoplasmic discrete speckles (CDS) in indirect immunofluorescence (IIF). A distinct CDS IIF pattern represented by 3–20 discrete speckles dispersed throughout the cytoplasm was identified among other cytoplasmic speckled IIF patterns. The cytoplasmic domains labelled by human anti-CDS-1 antibodies did not co-localize with endosome/lysosome markers EEA1 and LAMP-2, but showed partial co-localization with glycine–tryptophan bodies (GWB). CDS-1 sera did not react with several cellular extracts in immunoblotting and did not immunoprecipitate recombinant GW182 or EEA1 proteins. The typical CDS-1 IIF labelling pattern was abolished after delipidation of HEp-2 cells. Moreover, CDS-1 sera reacted strongly with a lipid component co-migrating with phosphatidylethanolamine (PE) in high performance thin-layer chromatography (HPTLC)-immunostaining of HEp-2 cell total lipid extracts. The CDS-1 major molecular targets were established by electrospray ionization–mass spectrometry (ESI-MS), HPTLC-immunostaining and chemiluminescent enzyme-linked immunosorbent assay as diacyl-PE species, containing preferentially a cis-C18 : 1 fatty acid chain at C-2 of the glycerol moiety, namely 1,2-cis-C18 : 1-PE and 1-C16 : 0-2-cis-C18 : 1-PE. The clinical association of CDS-1 sera included a variety of systemic and organ-specific autoimmune diseases but they were also observed in patients with no evidence of autoimmune disease. PMID:16487257

  18. Environmentally safe design of tailing dams for the management of iron ore tailings in Indian context.

    PubMed

    Ghose, Mrinal K; Sen, P K

    2005-10-01

    The need for the disposal of iron ore tailings in an enviornmentally firiendly manner is of great concern. This paper investigates the soil engineering properties for the construction of iron ore tailing dam, its foundation, construction materials and design data used for the construction analysis of the tailing dam. Geophysical investigations were carried out to establish the bedrock below the spillway. A computer programme taking into account the Swedish Slip Circle Method of analysis was used in the stability analysis of dam. It also focuses on the charactierstics of the tailings reponsible for the determination of optimum size of tailing pond for the containment of the tailings. The studies on the settling characteristics of tailings indicate much less area in comparison to the area provided in the existing tailing ponds in India. In the proposed scheme, it is suggested to provide an additional unit of sedimentation tank before the disposal of tailings to the tailing pond. PMID:17051916

  19. Uranium mill tailings quarterly report, January-March 1982

    SciTech Connect

    Latkovich, J.M.

    1982-05-01

    Progress is reported on: radon barrier systems for uranium mill tailings; liner evaluation for uranium mill tailings; revegetation/rock cover for stabilization of inactive U-tailings sites; and application of long-term chemical biobarriers for uranium tailings.

  20. Uptake and degradation of cytoplasmic RNA by lysosomes in the perfused rat liver

    SciTech Connect

    Heydrick, S.J.; Lardeux, B.; Mortimore, G.E.

    1987-05-01

    The release of (/sup 14/C)cytidine has been shown previously to be a valid marker for RNA degradation in rat hepatocytes. The breakdown of RNA measured with this marker in perfused livers prelabeled in vivo with (6-/sup 14/C)orotic acid was found to be regulated acutely by perfusate amino acids over a wide range, from 0.29 to 3.48%/h. This regulation paralleled that of lysosomal proteolysis. Chloroquine inhibited RNA degradation 60-70%. In subsequent cell fractionation studies labelled cytidine was released; the distribution of this release paralleled that of a lysosomal marker enzyme. The release plateaued after two hours, defining a distinct lysosomal pool of RNA. The lysosomal location of the RNA pool was confirmed in experiments where a 22% increase in the apparent pool size was obtained by lowering the homogenate pH from 7.0 to 5.5. The pool size correlated linearly with the rate of RNA degradation measured during perfusion, giving a turnover constant in reasonable agreement with values reported for autophagy. These results indicate that cytoplasmic RNA degradation occurs primarily in the lysosome and is regulated under these conditions by the amino acid control of lysosomal sequestration of cytoplasm.

  1. Growth signalobody selects functional intrabodies in the mammalian cytoplasm.

    PubMed

    Lee, Songhee; Kaku, Yoshihiro; Inoue, Satoshi; Nagamune, Teruyuki; Kawahara, Masahiro

    2016-03-01

    A versatile strategy to inhibit protein functions in the cytoplasmic environment is eagerly anticipated for drug discovery. In this study, we demonstrate a novel system to directly select functional intrabodies from a library in the mammalian cytoplasm. In this system, a target homo-oligomeric antigen is expressed together with a single-chain Fv (scFv) library that is linked to the cytoplasmic domain of a receptor tyrosine kinase (RTK) in the cytoplasm of murine interleukin-3 (IL-3)-dependent cells. As the tyrosine kinase is activated by dimerization, only scFv-RTK clones that can bind to the target antigen would be oligomerized and transduce a growth signal under the IL-3-deprived condition, which leads to selection of functional intrabodies. To demonstrate this system, we used rabies virus phosphoprotein (RV-P) that forms dimers in the cytoplasm as a target antigen. As a result, functional intrabodies were selected using our system from a naïve scFv library as well as from a pre-selected anti-RV-P library generated by phage display. This system may be applied for screening intrabodies that can prevent progression of various severe diseases. PMID:26647155

  2. Instanton calculus of Lifshitz tails

    NASA Astrophysics Data System (ADS)

    Yaida, Sho

    2016-02-01

    Some degree of quenched disorder is present in nearly all solids, and can have a marked impact on their macroscopic properties. A manifestation of this effect is the Lifshitz tail of localized states that then gets attached to the energy spectrum, resulting in the nonzero density of states in the band gap. We present here a systematic approach for deriving the asymptotic behavior of the density of states and of the typical shape of the disorder potentials in the Lifshitz tail. The analysis is carried out first for the well-controlled case of noninteracting particles moving in a Gaussian random potential and then for a broad class of disordered scale-invariant models—pertinent to a variety of systems ranging from semiconductors to semimetals to quantum critical systems. For relevant Gaussian disorder, we obtain the general expression for the density of states deep in the tail, with the rate of exponential suppression governed by the dynamical exponent and spatial dimensions. For marginally relevant disorder, however, we would expect a power-law scaling. We discuss the implications of these results for understanding conduction in disordered materials.

  3. Impact of acid mine drainage on haematological, histopathological and genotoxic effects in golden mahaseer, Tor putitora.

    PubMed

    Shahi, Neetu; Sarma, Debaji; Pandey, Jyoti; Das, Partha; Sarma, Dandadhar; Mallik, Sumanta Kumar

    2016-07-01

    The present study was carried out to evaluate sub-lethal mechanism of acid mine drainage toxicity in fingerlings (9.5 ± 2.4 cm) of golden mahseer, Tor putitora. Exposed fingerlings showed significant reduction (P < 0.01) in blood erythrocytes, neutrophils, thrombocytes, lymphocytes and leukocytes in contrast to increase in number of immature circulating cells. Hyperplasia, degeneration of glomeruli, presence of inflammatory cells and increased number of melanomacrophage aggregates, vacuolization of cell cytoplasm, hepatocyte swelling were marked in kidney and liver of fish. Ladder in, an increment of 180-200 bp of hepatic and kidney DNA, by electrophoresis were consistent with DNA damage. 10 day exposure to acid mine drainage resulted in reduction of double stranded DNA to 46.0 and 48.0 in hepatocytes and kidney cells respectively. Significant increase (P < 0.01) in tail length and percent tail DNA was evident by comet assay. The results suggest that exposure to acid mine drainage might cause irreversible damage to immune cells, tissue and DNA of fish, and this model of DNA damage may contribute in identifying novel molecular mechanism of interest for bioremediation application. PMID:27498494

  4. The Extracellular and Transmembrane Domains of the γC and Interleukin (IL)-13 Receptor α1 Chains, Not Their Cytoplasmic Domains, Dictate the Nature of Signaling Responses to IL-4 and IL-13

    PubMed Central

    Heller, Nicola M.; Qi, Xiulan; Gesbert, Franck; Keegan, Achsah D.

    2012-01-01

    Previously, we demonstrated that the γC subunit of type I IL-4 receptor was required for robust tyrosine phosphorylation of the downstream adapter protein, IRS-2, correlating with the expression of genes (ArgI, Retnla, and Chi3l3) characteristic of alternatively activated macrophages. We located an I4R-like motif (IRS-2 docking sequence) in the γC cytoplasmic domain but not in the IL-13Rα1. Thus, we predicted that the γC tail directed enhanced IRS-2 phosphorylation. To test this, IL-4 signaling responses were examined in a mutant of the key I4R motif tyrosine residue (Y325F) and different γC truncation mutants (γ285, γ308, γ318, γ323, and γFULL LENGTH (FL)) co-expressed in L-cells or CHO cells with wild-type (WT) IL-4Rα. Surprisingly, IRS-1 phosphorylation was not diminished in Y325F L-cell mutants suggesting Tyr-325 was not required for the robust insulin receptor substrate response. IRS-2, STAT6, and JAK3 phosphorylation was observed in CHO cells expressing γ323 and γFL but not in γ318 and γ285 mutants. In addition, when CHO cells expressed γ318, γ323, or γFL with IL-2Rβ, IL-2 induced phospho-STAT5 only in the γ323 and γFL clones. Our data suggest that a smaller (5 amino acid) interval than previously determined is necessary for JAK3 activation/γC-mediated signaling in response to IL-4 and IL-2. Chimeric receptor chains of the γC tail fused to the IL-13Rα1 extracellular and transmembrane domain did not elicit robust IRS-2 phosphorylation in response to IL-13 suggesting that the extracellular/transmembrane domains of the IL-4/IL-13 receptor, not the cytoplasmic domains, control signaling efficiency. Understanding this pathway fully will lead to rational drug design for allergic disease. PMID:22829596

  5. Testing the functional significance of tail streamers

    PubMed Central

    Evans, M. R.; Thomas, A. L. R.

    1997-01-01

    Studies of the evolution of elaborate ornaments have concentrated on their role in increasing attractiveness to mates. The classic examples of such sexually selected structures are the elongated tails of some bird species. Elongated tails can be divided into three categories: graduated tails, pin tails and streamers. There seems to be little debate about whether graduated and pin tails are ornaments; i.e. costly signals used in mate choice. However, in the case of streamers there is considerable discussion about their function. It has been suggested that tail streamers could be (i) entirely naturally selected, (ii) entirely sexually selected, (iii) partly naturally and partly sexually selected. The prime example of a species with tail streamers is the swallow (Hirundo rustica) in which both sexes have tail streamers. In this paper we discuss the aerodynamic consequences of different types of manipulation of the streamer and/or outer tail feather. We make qualitative predictions about the aerodynamic performance of swallows with manipulated tail streamers; these predictions differ depending on whether streamers have a naturally or sexually selected function. We demonstrate that these hypotheses can only be separated if tail streamers are shortened and changes in aerodynamic performance measured during turning flight.

  6. Curly tail: a 50-year history of the mouse spina bifida model.

    PubMed

    van Straaten, H W; Copp, A J

    2001-04-01

    This paper reviews 50 years of progress towards understanding the aetiology and pathogenesis of neural tube defects (NTD) in the curly tail (ct) mutant mouse. More than 45 papers have been published on various aspects of curly tail with the result that it is now the best understood mouse model of NTD pathogenesis. The failure of closure of the spinal neural tube, which leads to spina bifida in this mouse, has been traced back to a tissue-specific defect of cell proliferation in the tail bud of the E9.5 embryo. This cell proliferation defect results in a growth imbalance in the caudal region that generates ventral curvature of the body axis. Neurulation movements are opposed, leading to delayed neuropore closure and spina bifida, or tail defects. It is interesting to reflect that these advances have been achieved in the absence of information on the nature of the ct gene product, which remains unidentified. In addition to the principal ct gene, which maps to distal Chromosome 4, the curly tail phenotype is influenced by several modifier genes and by environmental factors. NTD in curly tail are resistant to folic acid, as is thought to be the case in 30% of human NTD, whereas they can be prevented by myo-inositol. These and other features of NTD in this system bear striking similarities to the situation in humans, making curly tail a model for understanding a sub-type folic acid-resistant human NTD. PMID:11396850

  7. Microtubule-associated protein-like binding of the kinesin-1 tail to microtubules.

    PubMed

    Seeger, Mark A; Rice, Sarah E

    2010-03-12

    The kinesin-1 molecular motor contains an ATP-dependent microtubule-binding site in its N-terminal head domain and an ATP-independent microtubule-binding site in its C-terminal tail domain. Here we demonstrate that a kinesin-1 tail fragment associates with microtubules with submicromolar affinity. Binding is largely electrostatic in nature, and is facilitated by a region of basic amino acids in the tail and the acidic E-hook at the C terminus of tubulin. The tail binds to a site on tubulin that is independent of the head domain-binding site but overlaps with the binding site of the microtubule-associated protein Tau. Surprisingly, the kinesin tail domain stimulates microtubule assembly and stability in a manner similar to Tau. The biological function of this strong kinesin tail-microtubule interaction remains to be seen, but it is likely to play an important role in kinesin regulation due to the close proximity of the microtubule-binding region to the conserved regulatory and cargo-binding domains of the tail. PMID:20071331

  8. Microtubule-associated Protein-like Binding of the Kinesin-1 Tail to Microtubules*

    PubMed Central

    Seeger, Mark A.; Rice, Sarah E.

    2010-01-01

    The kinesin-1 molecular motor contains an ATP-dependent microtubule-binding site in its N-terminal head domain and an ATP-independent microtubule-binding site in its C-terminal tail domain. Here we demonstrate that a kinesin-1 tail fragment associates with microtubules with submicromolar affinity. Binding is largely electrostatic in nature, and is facilitated by a region of basic amino acids in the tail and the acidic E-hook at the C terminus of tubulin. The tail binds to a site on tubulin that is independent of the head domain-binding site but overlaps with the binding site of the microtubule-associated protein Tau. Surprisingly, the kinesin tail domain stimulates microtubule assembly and stability in a manner similar to Tau. The biological function of this strong kinesin tail-microtubule interaction remains to be seen, but it is likely to play an important role in kinesin regulation due to the close proximity of the microtubule-binding region to the conserved regulatory and cargo-binding domains of the tail. PMID:20071331

  9. Extended string-like binding of the phosphorylated HP1α N-terminal tail to the lysine 9-methylated histone H3 tail

    PubMed Central

    Shimojo, Hideaki; Kawaguchi, Ayumi; Oda, Takashi; Hashiguchi, Nobuto; Omori, Satoshi; Moritsugu, Kei; Kidera, Akinori; Hiragami-Hamada, Kyoko; Nakayama, Jun-ichi; Sato, Mamoru; Nishimura, Yoshifumi

    2016-01-01

    The chromodomain of HP1α binds directly to lysine 9-methylated histone H3 (H3K9me). This interaction is enhanced by phosphorylation of serine residues in the N-terminal tail of HP1α by unknown mechanism. Here we show that phosphorylation modulates flexibility of HP1α’s N-terminal tail, which strengthens the interaction with H3. NMR analysis of HP1α’s chromodomain with N-terminal tail reveals that phosphorylation does not change the overall tertiary structure, but apparently reduces the tail dynamics. Small angle X-ray scattering confirms that phosphorylation contributes to extending HP1α’s N-terminal tail. Systematic analysis using deletion mutants and replica exchange molecular dynamics simulations indicate that the phosphorylated serines and following acidic segment behave like an extended string and dynamically bind to H3 basic residues; without phosphorylation, the most N-terminal basic segment of HP1α inhibits interaction of the acidic segment with H3. Thus, the dynamic string-like behavior of HP1α’s N-terminal tail underlies the enhancement in H3 binding due to phosphorylation. PMID:26934956

  10. Mobilization of radionuclides from uranium mill tailings and related waste materials in anaerobic environments

    USGS Publications Warehouse

    Landa, E.R.

    2003-01-01

    Specific extraction studies in our laboratory have shown that iron and manganese oxide- and alkaline earth sulfate minerals are important hosts of radium in uranium mill tailings. Iron- and sulfate-reducing bacteria may enhance the release of radium (and its analog barium) from uranium mill tailings, oil field pipe scale [a major technologically enhanced naturally occurring radioactive material (TENORM) waste], and jarosite (a common mineral in sulfuric acid processed-tailings). These research findings are reviewed and discussed in the context of nuclear waste forms (such as barium sulfate matrices), radioactive waste management practices, and geochemical environments in the Earth's surficial and shallow subsurface regions.

  11. Characterization of sorCS1, an alternatively spliced receptor with completely different cytoplasmic domains that mediate different trafficking in cells.

    PubMed

    Hermey, Guido; Keat, Sady J; Madsen, Peder; Jacobsen, Christian; Petersen, Claus M; Gliemann, Jorgen

    2003-02-28

    We previously isolated and sequenced murine sorCS1, a type 1 receptor containing a Vps10p-domain and a leucine-rich domain. We now show that human sorCS1 has three isoforms, sorCS1a-c, with completely different cytoplasmic tails and differential expression in tissues. The b tail shows high identity with that of murine sorCS1b, whereas the a and c tails have no reported counterparts. Like the Vps10p-domain receptor family members sortilin and sorLA, sorCS1 is synthesized as a proreceptor that is converted in late Golgi compartments by furin-mediated cleavage. Mature sorCS1 bound its own propeptide with low affinity but none of the ligands previously shown to interact with sortilin and sorLA. In transfected cells, about 10% of sorCS1a was expressed on the cell surface and proved capable of rapid endocytosis in complex with specific antibody, whereas sorCS1b presented a high cell surface expression but essentially no endocytosis, and sorCS1c was intermediate. This is an unusual example of an alternatively spliced single transmembrane receptor with completely different cytoplasmic domains that mediate different trafficking in cells. PMID:12482870

  12. Effective cytoplasmic release of siRNA from liposomal carriers by controlling the electrostatic interaction of siRNA with a charge-invertible peptide, in response to cytoplasmic pH

    NASA Astrophysics Data System (ADS)

    Itakura, Shoko; Hama, Susumu; Matsui, Ryo; Kogure, Kentaro

    2016-05-01

    Condensing siRNA with cationic polymers is a major strategy used in the development of siRNA carriers that can avoid degradation by nucleases and achieve effective delivery of siRNA into the cytoplasm. However, ineffective release of siRNA from such condensed forms into the cytoplasm is a limiting step for induction of RNAi effects, and can be attributed to tight condensation of siRNA with the cationic polymers, due to potent electrostatic interactions. Here, we report that siRNA condensed with a slightly acidic pH-sensitive peptide (SAPSP), whose total charge is inverted from positive to negative in response to cytoplasmic pH, is effectively released via electrostatic repulsion of siRNA with negatively charged SAPSP at cytoplasmic pH (7.4). The condensed complex of siRNA and positively-charged SAPSP at acidic pH (siRNA/SAPSP) was found to result in almost complete release of siRNA upon charge inversion of SAPSP at pH 7.4, with the resultant negatively-charged SAPSP having no undesirable interactions with endogenous mRNA. Moreover, liposomes encapsulating siRNA/SAPSP demonstrated knockdown efficiencies comparable to those of commercially available siRNA carriers. Taken together, SAPSP may be very useful as a siRNA condenser, as it facilitates effective cytoplasmic release of siRNA, and subsequent induction of specific RNAi effects.Condensing siRNA with cationic polymers is a major strategy used in the development of siRNA carriers that can avoid degradation by nucleases and achieve effective delivery of siRNA into the cytoplasm. However, ineffective release of siRNA from such condensed forms into the cytoplasm is a limiting step for induction of RNAi effects, and can be attributed to tight condensation of siRNA with the cationic polymers, due to potent electrostatic interactions. Here, we report that siRNA condensed with a slightly acidic pH-sensitive peptide (SAPSP), whose total charge is inverted from positive to negative in response to cytoplasmic pH, is

  13. BACE1 retrograde trafficking is uniquely regulated by the cytoplasmic domain of sortilin.

    PubMed

    Finan, Gina M; Okada, Hirokazu; Kim, Tae-Wan

    2011-04-01

    BACE1 (β-site β-amyloid precursor protein (APP)-cleaving enzyme 1) mediates the first proteolytic cleavage of APP, leading to amyloid β-peptide (Aβ) production. It has been reported that BACE1 intracellular trafficking, in particular endosome-to-TGN sorting, is mediated by adaptor complexes, such as retromer and Golgi-localized γ-ear-containing ARF-binding proteins (GGAs). Here we investigated whether sortilin, a Vps10p domain-sorting receptor believed to participate in retromer-mediated transport of select membrane cargoes, contributes to the subcellular trafficking and activity of BACE1. Our initial studies revealed increased levels of sortilin in post-mortem brain tissue of AD patients and that overexpression of sortilin leads to increased BACE1-mediated cleavage of APP in cultured cells. In contrast, RNAi suppression of sortilin results in decreased BACE1-mediated cleavage of APP. We also found that sortilin interacts with BACE1 and that a sortilin construct lacking its cytoplasmic domain, which contains putative retromer sorting motifs, remains bound to BACE1. However, expression of this truncated sortilin redistributes BACE1 from the trans-Golgi network to the endosomes and substantially reduces the retrograde trafficking of BACE1. Site-directed mutagenesis and chimera experiments reveal that the cytoplasmic tail of sortilin, but not those from other VPS10p domain receptors (e.g. SorCs1b and SorLA), plays a unique role in BACE1 trafficking. Our studies suggest a new function for sortilin as a modulator of BACE1 retrograde trafficking and subsequent generation of Aβ. PMID:21245145

  14. The hydrogeology of a tailings impoundment formed by central discharge of thickened tailings: implications for tailings management

    NASA Astrophysics Data System (ADS)

    Al, Tom A.; Blowes, David W.

    1999-06-01

    The Kidd Creek Cu-Zn sulfide mine is located near Timmins, Ontario. Mill tailings are thickened and deposited as a slurry in a circular impoundment with an area of approximately 1200 ha. Deposition of tailings as a thickened slurry from a central discharge ramp results in a conical-shaped tailings deposit with low perimeter dykes, a uniform grain-size distribution, uniform and low hydraulic conductivity, and a tension-saturated zone above the water table up to 5 to 6 m thick. These characteristics provide benefits over conventionally disposed tailings with respect to tailings management. The thick tension-saturated zone within the tailings limits the thickness of unsaturated tailings that are susceptible to rapid sulfide oxidation. The conical shape of the deposit results in the formation of a recharge area near the centre of the impoundment and discharge in the peripheral areas. In contrast, the elevated nature of many conventional, unthickened tailings impoundments results in recharge over most of the surface of the impoundment, with discharge occurring outside the impoundment through large containment dykes. Three-dimensional pore water flow modelling suggests that approximately 90% of the total discharge from the thickened tailings occurs within the tailings impoundment. When discharge is confined within the impoundment, there is improved control over low-quality effluent, and an opportunity to design passive control measures to reduce treatment costs and minimize environmental impacts.

  15. Cleavage of cytoplasm within the oligonucleate zoosporangia of allomyces macrogynus.

    PubMed

    Ji, Yunjeong; Song, Youngsun; Kim, Namhun; Youn, Hyunjoo; Kang, Minkook; Song, Yurim; Cho, Chungwon

    2014-01-01

    Allomyces macrogynus produces zoosporangia that discharge uninucleate zoospores after cleavage of multinucleate cytoplasm. Cleavage of cytoplasm within the oligonucleate zoosporangia of A. macrogynus was visualized by constructing three-dimensional models based on electron micrographs and confocal images. In oligonucleate zoosporangia, three adjacent nuclei can form three cleavage planes with a line of intersection of the planes. The position and boundary of the cleavage planes are thought to be determined by the relative positions of the nuclei. The establishment of three cleavage planes by cleavage membranes occurred sequentially, and the nuclear axis connecting the centers of two nuclei affected the development of cleavage membranes on each cleavage plane. In multinucleate zoosporangia, groups of three neighboring nuclei near the cell cortex may initiate the sequential establishment of cleavage planes and then may interact with the nuclei further from the cortex until the interactions of nuclei are propagated to the central region of the cytoplasm. PMID:24871589

  16. Nuclear export modulates the cytoplasmic Sir2 homologue Hst2

    PubMed Central

    Wilson, Jeanne M; Le, Viet Q; Zimmerman, Collin; Marmorstein, Ronen; Pillus, Lorraine

    2006-01-01

    Modulating transcription factors is crucial to executing sophisticated gene expression programs. The silent information regulator 2 (Sir2) family of NAD-dependent protein deacetylases influences transcription by targeting proteins such as histones, p53 and forkhead-box family transcription factors. Although apparently cytoplasmic, both mammalian SIRT2 and its yeast orthologue Hst2 have been implicated in transcriptional regulation. Here, we show that Hst2 moves between the nucleus and cytoplasm, but is largely cytoplasmic owing to efficient nuclear export. This nuclear exclusion is mediated by the exportin chromosomal region maintenance 1 (Crm1) and a putative leucine-rich nuclear export sequence in Hst2, which overlaps a unique autoregulatory helix. Disruption of Hst2 export shows that nuclear exclusion inhibits the activity of Hst2 as a transcriptional repressor. Our identification of putative nuclear export sequences in numerous vertebrate SIRT2 proteins shows that active nuclear export can be a conserved mechanism for regulating Sir2 homologues. PMID:17110954

  17. Cytoplasmic dynein heavy chain: the servant of many masters

    PubMed Central

    Schiavo, Giampietro; Greensmith, Linda; Hafezparast, Majid; Fisher, Elizabeth M.C.

    2013-01-01

    Cytoplasmic dynein is the main retrograde motor in all eukaryotic cells. This complex comprises different subunits assembled on a cytoplasmic dynein heavy chain 1 (DYNC1H1) dimer. Cytoplasmic dynein is particularly important for neurons because it carries essential signals and organelles from distal sites to the cell body. In the past decade, several mouse models have helped to dissect the numerous functions of DYNC1H1. Additionally, several DYNC1H1 mutations have recently been found in human patients that give rise to a broad spectrum of developmental and midlife-onset disorders. Here, we discuss the effects of mutations of mouse and human DYNC1H1 and how these studies are giving us new insight into the many critical roles DYNC1H1 plays in the nervous system. PMID:24035135

  18. Biotoxicity assays for fruiting body lectins and other cytoplasmic proteins.

    PubMed

    Künzler, Markus; Bleuler-Martinez, Silvia; Butschi, Alex; Garbani, Mattia; Lüthy, Peter; Hengartner, Michael O; Aebi, Markus

    2010-01-01

    Recent studies suggest that a specific class of fungal lectins, commonly referred to as fruiting body lectins, play a role as effector molecules in the defense of fungi against predators and parasites. Hallmarks of these fungal lectins are their specific expression in reproductive structures, fruiting bodies, and/or sclerotia and their synthesis on free ribosomes in the cytoplasm. Fruiting body lectins are released upon damage of the fungal cell and bind to specific carbohydrate structures of predators and parasites, which leads to deterrence, inhibition of growth, and development or even killing of these organisms. Here, we describe assays to assess the toxicity of such lectins and other cytoplasmic proteins toward three different model organisms: the insect Aedes aegypti, the nematode Caenorhabditis elegans, and the amoeba Acanthamoeba castellanii. All three assays are based on heterologous expression of the examined proteins in the cytoplasm of Escherichia coli and feeding of these recombinant bacteria to omnivorous and bacterivorous organisms. PMID:20816208

  19. Organelle Simple Sequence Repeat Markers Help to Distinguish Carpelloid Stamen and Normal Cytoplasmic Male Sterile Sources in Broccoli

    PubMed Central

    Shu, Jinshuai; Liu, Yumei; Li, Zhansheng; Zhang, Lili; Fang, Zhiyuan; Yang, Limei; Zhuang, Mu; Zhang, Yangyong; Lv, Honghao

    2015-01-01

    We previously discovered carpelloid stamens when breeding cytoplasmic male sterile lines in broccoli (Brassica oleracea var. italica). In this study, hybrids and multiple backcrosses were produced from different cytoplasmic male sterile carpelloid stamen sources and maintainer lines. Carpelloid stamens caused dysplasia of the flower structure and led to hooked or coiled siliques with poor seed setting, which were inherited in a maternal fashion. Using four distinct carpelloid stamens and twelve distinct normal stamens from cytoplasmic male sterile sources and one maintainer, we used 21 mitochondrial simple sequence repeat (mtSSR) primers and 32 chloroplast SSR primers to identify a mitochondrial marker, mtSSR2, that can differentiate between the cytoplasm of carpelloid and normal stamens. Thereafter, mtSSR2 was used to identify another 34 broccoli accessions, with an accuracy rate of 100%. Analysis of the polymorphic sequences revealed that the mtSSR2 open reading frame of carpelloid stamen sterile sources had a deletion of 51 bases (encoding 18 amino acids) compared with normal stamen materials. The open reading frame is located in the coding region of orf125 and orf108 of the mitochondrial genomes in Brassica crops and had the highest similarity with Raphanus sativus and Brassica carinata. The current study has not only identified a useful molecular marker to detect the cytoplasm of carpelloid stamens during broccoli breeding, but it also provides evidence that the mitochondrial genome is maternally inherited and provides a basis for studying the effect of the cytoplasm on flower organ development in plants. PMID:26407159

  20. Organelle Simple Sequence Repeat Markers Help to Distinguish Carpelloid Stamen and Normal Cytoplasmic Male Sterile Sources in Broccoli.

    PubMed

    Shu, Jinshuai; Liu, Yumei; Li, Zhansheng; Zhang, Lili; Fang, Zhiyuan; Yang, Limei; Zhuang, Mu; Zhang, Yangyong; Lv, Honghao

    2015-01-01

    We previously discovered carpelloid stamens when breeding cytoplasmic male sterile lines in broccoli (Brassica oleracea var. italica). In this study, hybrids and multiple backcrosses were produced from different cytoplasmic male sterile carpelloid stamen sources and maintainer lines. Carpelloid stamens caused dysplasia of the flower structure and led to hooked or coiled siliques with poor seed setting, which were inherited in a maternal fashion. Using four distinct carpelloid stamens and twelve distinct normal stamens from cytoplasmic male sterile sources and one maintainer, we used 21 mitochondrial simple sequence repeat (mtSSR) primers and 32 chloroplast SSR primers to identify a mitochondrial marker, mtSSR2, that can differentiate between the cytoplasm of carpelloid and normal stamens. Thereafter, mtSSR2 was used to identify another 34 broccoli accessions, with an accuracy rate of 100%. Analysis of the polymorphic sequences revealed that the mtSSR2 open reading frame of carpelloid stamen sterile sources had a deletion of 51 bases (encoding 18 amino acids) compared with normal stamen materials. The open reading frame is located in the coding region of orf125 and orf108 of the mitochondrial genomes in Brassica crops and had the highest similarity with Raphanus sativus and Brassica carinata. The current study has not only identified a useful molecular marker to detect the cytoplasm of carpelloid stamens during broccoli breeding, but it also provides evidence that the mitochondrial genome is maternally inherited and provides a basis for studying the effect of the cytoplasm on flower organ development in plants. PMID:26407159

  1. AMPK Signaling Results in Cytoplasmic Sequestration of p27

    PubMed Central

    Short, John D.; Houston, Kevin D.; Dere, Ruhee; Cai, Sheng-Li; Kim, Jinhee; Johnson, Charles L.; Broaddus, Russell R.; Shen, Jianjun; Miyamoto, Susie; Tamanoi, Fuyuhiko; Kwiatkowski, David; Mills, Gordon B.; Walker, Cheryl Lyn

    2009-01-01

    Tuberin, the Tsc2 gene product, integrates PI3K/MAPK (mitogenic) and LKB1/AMPK (energy) signaling pathways, and previous independent studies have shown that loss of tuberin is associated with elevated AMPK signaling and altered p27 function. In Tsc2-null tumors and tumor-derived cells from Eker rats, we observed elevated AMPK signaling and concordant cytoplasmic mislocalization of p27. Cytoplasmic localization of p27 in Tsc2-null cells was reversible pharmacologically using inhibitors of the LKB1/AMPK pathway, and localization of p27 to the cytoplasm could be induced directly by activating AMPK physiologically (glucose deprivation) or genetically (constitutively-active AMPK) in Tsc2-proficient cells. Furthermore, AMPK phosphorylated p27 in vitro on at least three sites including T170 near the NLS, and T170 was demonstrated to determine p27 localization in response to AMPK signaling. p27 functions in the nucleus to suppress Cdk2 activity, and has been reported to mediate an anti-apoptotic function when localized to the cytoplasm. We found that cells with elevated AMPK signaling and cytoplasmic p27 localization exhibited elevated Cdk2 activity, which could be suppressed by inhibiting AMPK signaling. In addition, cells with elevated AMPK signaling and cytoplasmic p27 localization were resistant to apoptosis, which could be overcome by inhibition of AMPK signaling and relocalization of p27 to the nucleus. These data demonstrate that AMPK signaling determines the subcellular localization of p27, and identifies loss of integration of pathways controlling energy balance, the cell cycle and apoptosis due to aberrant AMPK and p27 function as a feature of cells that have lost the Tsc2 tumor suppressor gene. PMID:18701472

  2. Transcription factor TFII-I conducts a cytoplasmic orchestra.

    PubMed

    Roy, Ananda L

    2006-11-21

    In response to extracellular ligands, surface receptor tyrosine kinases and G-protein-coupled receptors activate isoforms of phospholipase C (PLC) and initiate calcium signaling. PLC can activate expression of surface transient receptor potential channels (TRPC) such as TRPC3, which modulate calcium entry through the plasma membrane. A recent paper shows that competitive binding of cytoplasmic TFII-I, a transcription factor, to PLC-gamma results in inhibition of TRPC3-mediated agonist-induced Ca(2+) entry. These results establish a novel cytoplasmic function for TFII-I. PMID:17168565

  3. Role of the long cytoplasmic domain of the SIV Env glycoprotein in early and late stages of infection

    PubMed Central

    Vzorov, Andrei N; Weidmann, Armin; Kozyr, Natalia L; Khaoustov, Vladimir; Yoffe, Boris; Compans, Richard W

    2007-01-01

    Background The Env glycoproteins of retroviruses play an important role in the initial steps of infection involving the binding to cell surface receptors and entry by membrane fusion. The Env glycoprotein also plays an important role in viral assembly at a late step of infection. Although the Env glycoprotein interacts with viral matrix proteins and cellular proteins associated with lipid rafts, its possible role during the early replication events remains unclear. Truncation of the cytoplasmic tail (CT) of the Env glycoprotein is acquired by SIV in the course of adaptation to human cells, and is known to be a determinant of SIV pathogenicity. Results We compared SIV viruses with full length or truncated (T) Env glycoproteins to analyze possible differences in entry and post-entry events, and assembly of virions. We observed that early steps in replication of SIV with full length or T Env were similar in dividing and non-dividing cells. However, the proviral DNA of the pathogenic virus clone SIVmac239 with full length Env was imported to the nucleus about 20-fold more efficiently than proviral DNA of SIVmac239T with T Env, and 100-fold more efficiently than an SIVmac18T variant with a single mutation A239T in the SU subunit and with a truncated cytoplasmic tail (CT). In contrast, proviral DNA of SIVmac18 with a full length CT and with a single mutation A239T in the SU subunit was imported to the nucleus about 50-fold more efficiently than SIVmac18T. SIV particles with full length Env were released from rhesus monkey PBMC, whereas a restriction of release of virus particles was observed from human 293T, CEMx174, HUT78 or macrophages. In contrast, SIV with T Envs were able to overcome the inhibition of release in human HUT78, CEMx174, 293T or growth-arrested CEMx174 cells and macrophages resulting in production of infectious particles. We found that the long CT of the Env glycoprotein was required for association of Env with lipid rafts. An Env mutant C787S which

  4. Coupled Ca2+/H+ transport by cytoplasmic buffers regulates local Ca2+ and H+ ion signaling.

    PubMed

    Swietach, Pawel; Youm, Jae-Boum; Saegusa, Noriko; Leem, Chae-Hun; Spitzer, Kenneth W; Vaughan-Jones, Richard D

    2013-05-28

    Ca(2+) signaling regulates cell function. This is subject to modulation by H(+) ions that are universal end-products of metabolism. Due to slow diffusion and common buffers, changes in cytoplasmic [Ca(2+)] ([Ca(2+)]i) or [H(+)] ([H(+)]i) can become compartmentalized, leading potentially to complex spatial Ca(2+)/H(+) coupling. This was studied by fluorescence imaging of cardiac myocytes. An increase in [H(+)]i, produced by superfusion of acetate (salt of membrane-permeant weak acid), evoked a [Ca(2+)]i rise, independent of sarcolemmal Ca(2+) influx or release from mitochondria, sarcoplasmic reticulum, or acidic stores. Photolytic H(+) uncaging from 2-nitrobenzaldehyde also raised [Ca(2+)]i, and the yield was reduced following inhibition of glycolysis or mitochondrial respiration. H(+) uncaging into buffer mixtures in vitro demonstrated that Ca(2+) unloading from proteins, histidyl dipeptides (HDPs; e.g., carnosine), and ATP can underlie the H(+)-evoked [Ca(2+)]i rise. Raising [H(+)]i tonically at one end of a myocyte evoked a local [Ca(2+)]i rise in the acidic microdomain, which did not dissipate. The result is consistent with uphill Ca(2+) transport into the acidic zone via Ca(2+)/H(+) exchange on diffusible HDPs and ATP molecules, energized by the [H(+)]i gradient. Ca(2+) recruitment to a localized acid microdomain was greatly reduced during intracellular Mg(2+) overload or by ATP depletion, maneuvers that reduce the Ca(2+)-carrying capacity of HDPs. Cytoplasmic HDPs and ATP underlie spatial Ca(2+)/H(+) coupling in the cardiac myocyte by providing ion exchange and transport on common buffer sites. Given the abundance of cellular HDPs and ATP, spatial Ca(2+)/H(+) coupling is likely to be of general importance in cell signaling. PMID:23676270

  5. Thermo-mechanical properties and microfabric of fly ash-stabilized gold tailings.

    PubMed

    Lee, Joon Kyu; Shang, Julie Q; Jeong, Sangseom

    2014-07-15

    This paper studies the changes in thermal conductivity, temperature, and unconfined compressive strength of gold tailings and fly ash mixtures during the curing period of 5 days. The microfabric of the cured mixtures was investigated with mercury intrusion porosimetry (MIP). The mixture samples were prepared at their maximum dry unit weight and optimum moisture content. Effect of adding fly ash to gold tailings (i.e., 0, 20, and 40% of the dry weight of tailings) was examined, and a comparison was made on samples prepared at the same fly ash content by replacing gold tailings with humic acid (i.e., gold tailings and humic acid ratios of 100:0, 90:10, and 80:20 by weight) or by varying pore fluid chemistry (i.e., water and salt solutions of 1M NaCl and CaCl2). The results show that the initial thermal conductivity of the samples is sensitive to the mixture proportion and a declination in the thermal conductivity is observed due to hydration of fly ash and evaporation. Inclusion of fly ash and salts into gold tailings improves the unconfined compressive strength but the presence of humic acid in samples leads to the decrease of the strength. MIP results reveal the pore structure changes associated with the packing states of the samples that reflect the influential factors considered. PMID:24910909

  6. Human FcγRII cytoplasmic domains differentially influence antibody-mediated dengue virus infection.

    PubMed

    Boonnak, Kobporn; Slike, Bonnie M; Donofrio, Gina C; Marovich, Mary A

    2013-06-01

    Ab-dependent enhancement (ADE) of dengue virus (DENV) infection is mediated through the interaction of viral immune complexes with FcγRs, with notable efficiency of FcγRII. Most human dengue target cells coexpress activating (FcγRIIa) and inhibitory (FcγRIIb) isoforms, but their relative roles in ADE are not well understood. We studied the effects of FcγRIIa and FcγRIIb by transfecting cells to express each individual receptor isoform or through coexpression of both isoforms. We showed that although both isoforms similarly bind dengue-immune complexes, FcγRIIa efficiently internalized virus leading to productive cellular infection, unlike FcγRIIb. We next focused on the main discriminating feature of these isoforms: their distinct intracytoplasmic tails (FcγRIIa with an immunoreceptor tyrosine-based activation motif [ITAM] and FcγRIIb with an immunoreceptor tyrosine-based inhibitory motif [ITIM]). We engineered cells to express "swapped" versions of their FcγRII by switching the cytoplasmic tails containing the ITAM/ITIM motifs, leaving the remainder of the receptor intact. Our data show that both FcγRIIa and FcγRIIb comparably bind dengue immune complexes. However, wild type FcγRIIa facilitates DENV entry by virtue of the ITAM motif, whereas the swapped version FcγRIIa-ITIM significantly inhibited ADE. Similarly, replacing the inhibitory motif in FcγRIIb with an ITAM (FcγRIIb-ITAM) reconstituted ADE capacity to levels of the wild type activating counterpart, FcγRIIa. Our data suggest that FcγRIIa and FcγRIIb isoforms, as the most abundantly distributed class II Fcγ receptors, differentially influence Ab-mediated DENV infection under ADE conditions both at the level of cellular infection and viral production. PMID:23616574

  7. Human FcγRII Cytoplasmic Domains Differentially Influence Antibody-Mediated Dengue Virus Infection

    PubMed Central

    Boonnak, Kobporn; Slike, Bonnie M.; Donofrio, Gina C.

    2013-01-01

    Ab-dependent enhancement (ADE) of dengue virus (DENV) infection is mediated through the interaction of viral immune complexes with FcγRs, with notable efficiency of FcγRII. Most human dengue target cells coexpress activating (FcγRIIa) and inhibitory (FcγRIIb) isoforms, but their relative roles in ADE are not well understood. We studied the effects of FcγRIIa and FcγRIIb by transfecting cells to express each individual receptor isoform or through coexpression of both isoforms. We showed that although both isoforms similarly bind dengue-immune complexes, FcγRIIa efficiently internalized virus leading to productive cellular infection, unlike FcγRIIb. We next focused on the main discriminating feature of these isoforms: their distinct intracytoplasmic tails (FcγRIIa with an immunoreceptor tyrosine-based activation motif [ITAM] and FcγRIIb with an immunoreceptor tyrosine-based inhibitory motif [ITIM]). We engineered cells to express “swapped” versions of their FcγRII by switching the cytoplasmic tails containing the ITAM/ITIM motifs, leaving the remainder of the receptor intact. Our data show that both FcγRIIa and FcγRIIb comparably bind dengue immune complexes. However, wild type FcγRIIa facilitates DENV entry by virtue of the ITAM motif, whereas the swapped version FcγRIIa-ITIM significantly inhibited ADE. Similarly, replacing the inhibitory motif in FcγRIIb with an ITAM (FcγRIIb-ITAM) reconstituted ADE capacity to levels of the wild type activating counterpart, FcγRIIa. Our data suggest that FcγRIIa and FcγRIIb isoforms, as the most abundantly distributed class II Fcγ receptors, differentially influence Ab-mediated DENV infection under ADE conditions both at the level of cellular infection and viral production. PMID:23616574

  8. Enhancing the safety of tailings management facilities

    SciTech Connect

    Meggyes, T.; Niederleithinger, E.; Witt, K.J.; Csovari, M.; Kreft-Burman, K.; Engels, J.; McDonald, C.; Roehl, K.E.

    2008-07-01

    Unsafe tailings management facilities (TMFs) have caused serious accidents in Europe threatening human health/life and the environment. While advanced design, construction and management procedures are available, their implementation requires greater emphasis. An integrated research project funded by the European Union was carried out between 2002 and 2005 with the overall goal of improving the safety of TMFs (Sustainable Improvement in Safety of Tailings Facilities - TAILSAFE, http://www.tailsafe.com/). The objective of TAILSAFE was to develop and apply methods of parameter evaluation and measurement for the assessment and improvement of the safety state of tailings facilities, with particular attention to the stability of tailings dams and slurries, the special risks inherent when such materials include toxic or hazardous wastes, and authorization and management procedures for tailings facilities. Aspects of tailings facilities design, water management and slurry transport, non-destructive and minimally intrusive testing methods, monitoring and the application of sensors, intervention and remediation options were considered in TAILSAFE. A risk reduction framework (the TAILSAFE Parameter Framework) was established to contribute to the avoidance of catastrophic accidents and hazards from tailings facilities. Tailings from the mining and primary processing of metals, minerals and coal were included within the scope of TAILSAFE. The project focused on the avoidance of hazards by developing procedures and methods for investigating and improving the stability of tailings dams and tailings bodies.

  9. Crystal and cryoEM structural studies of a cell wall degrading enzyme in the bacteriophage [psi]29 tail

    SciTech Connect

    Xiang, Ye; Morais, Marc C.; Cohen, Daniel N.; Bowman, Valorie D.; Anderson, Dwight L.; Rossmann, Michael G.

    2009-08-28

    The small bacteriophage {phi}29 must penetrate the {approx}250-{angstrom} thick external peptidoglycan cell wall and cell membrane of the Gram-positive Bacillus subtilis, before ejecting its dsDNA genome through its tail into the bacterial cytoplasm. The tail of bacteriophage {phi}29 is noncontractile and {approx}380 {angstrom} long. A 1.8-{angstrom} resolution crystal structure of gene product 13 (gp13) shows that this tail protein has spatially well separated N- and C-terminal domains, whose structures resemble lysozyme-like enzymes and metallo-endopeptidases, respectively. CryoEM reconstructions of the WT bacteriophage and mutant bacteriophages missing some or most of gp13 shows that this enzyme is located at the distal end of the {phi}29 tail knob. This finding suggests that gp13 functions as a tail-associated, peptidoglycan-degrading enzyme able to cleave both the polysaccharide backbone and peptide cross-links of the peptidoglycan cell wall. Comparisons of the gp13{sup -} mutants with the {phi}29 mature and emptied phage structures suggest the sequence of events that occur during the penetration of the tail through the peptidoglycan layer.

  10. Near-tail reconnection as the cause of cometary tail disconnections

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Saunders, M. A.; Phillips, J. L.; Fedder, J. A.

    1986-01-01

    In a cometary tail disconnection event the plasma tail appears to separate from the coma and to accelerate away from it. As this occurs a new tail begins to form. It is proposed that these disconnections arise in a manner analogous to geomagnetic substorms, i.e., by the formation of a strongly reconnecting region in the near tail that forms a magnetic island in the coma and ejects the plasma tail by strengthening the magnetic 'slingshot' within the tail. This reconnection process may be triggered by several different processes, such as interplanetary shocks or variations in the Alfven Mach number.

  11. Mature mRNAs accumulated in the nucleus are neither the molecules in transit to the cytoplasm nor constitute a stockpile for gene expression.

    PubMed Central

    Weil, D; Boutain, S; Audibert, A; Dautry, F

    2000-01-01

    In higher eukaryotes, the regulation of pre-mRNA processing is still poorly known. The accumulation of various mature mRNAs, which can be observed in the nuclei of mammalian cells, is suggestive of a regulatory role of transport. However, the significance of these nuclear mRNA is presently unknown. We have used a tetracycline-regulated promoter to investigate the dynamics of these pools of mRNAs upon arrest of transcription. We observed, for beta-globin and LT-alpha genes, a slow disappearance of these mRNA from the nucleus, with an apparent half-life that is similar to their cytoplasmic half-life. In view of these dynamics, these mRNA cannot simply be mature mRNAs in transit to the cytoplasm. They could be mRNAs retained in the nucleus, provided that the regulation of mRNA stability is comparable in the nucleus and the cytoplasm. But, because of their limited stability, these nuclear mRNAs cannot constitute a significant stock for gene expression. Alternatively, they could reflect a bidirectional transport of mRNA, that is, to and from the cytoplasm, which would provide a direct explanation for the similarity in both compartments of their half-life and poly(A) tail shortening over time. PMID:10917593

  12. Metal leaching in mine tailings: short-term impact of biochar and wood ash amendments.

    PubMed

    Beauchemin, Suzanne; Clemente, Joyce S; MacKinnon, Ted; Tisch, Bryan; Lastra, Rolando; Smith, Derek; Kwong, John

    2015-01-01

    Biochar is perceived as a promising amendment to reclaim degraded, metal-contaminated lands. The objective of this study was to compare the potential of biochar and wood ash amendments to reduce metal(loid) leaching in mine tailings. A 2-mo leaching experiment was conducted in duplicate on acidic and alkaline tailings, each mixed with 5 wt.% of one of the following amendments: three wood-derived, fast-pyrolysis biochars (OC > 57 wt.%) and two wood ash materials (organic carbon [OC] ≤ 16 wt.%); a control test with no carbon input was also added. The columns were leached with water after 1, 2, 4, 8, 16, 32, and 64 d, and the leachates were monitored for dissolved metals, OC, and pH. For the acidic and alkaline tailings, the most significant impact on metal mobility was observed with wood ash materials due to their greater neutralization potential (>15% CaCO eq.) compared with biochar (≤3.3% CaCO eq.). An increase of 1 pH unit in the wood ash-treated alkaline tailings led to an undesirable mobilization of As and Se. The addition of biochar did not significantly reduce the leaching of the main contaminants (Cu and Ni in the acidic tailings and As in the alkaline tailings) over 2 mo. The Se attenuation noted in some biochar-treated acid tailings may be mainly due to a slight alkaline effect rather than Se removal by biochar, given the low capacity for the fresh biochars to retain Se under acidic conditions (pH 4.5). The increased loss of dissolved OC in the biochar-amended systems was of short duration and was not associated with metal(loid) mobilization. PMID:25602343

  13. Optomechatronic System For Automated Intra Cytoplasmic Sperm Injection

    NASA Astrophysics Data System (ADS)

    Shulev, Assen; Tiankov, Tihomir; Ignatova, Detelina; Kostadinov, Kostadin; Roussev, Ilia; Trifonov, Dimitar; Penchev, Valentin

    2015-12-01

    This paper presents a complex optomechatronic system for In-Vitro Fertilization (IVF), offering almost complete automation of the Intra Cytoplasmic Sperm Injection (ICSI) procedure. The compound parts and sub-systems, as well as some of the computer vision algorithms, are described below. System capabilities for ICSI have been demonstrated on infertile oocyte cells.

  14. Structure of a Cytoplasmic 11-Subunit RNA Exosome Complex.

    PubMed

    Kowalinski, Eva; Kögel, Alexander; Ebert, Judith; Reichelt, Peter; Stegmann, Elisabeth; Habermann, Bianca; Conti, Elena

    2016-07-01

    The RNA exosome complex associates with nuclear and cytoplasmic cofactors to mediate the decay, surveillance, or processing of a wide variety of transcripts. In the cytoplasm, the conserved core of the exosome (Exo10) functions together with the conserved Ski complex. The interaction of S. cerevisiae Exo10 and Ski is not direct but requires a bridging cofactor, Ski7. Here, we report the 2.65 Å resolution structure of S. cerevisiae Exo10 bound to the interacting domain of Ski7. Extensive hydrophobic interactions rationalize the high affinity and stability of this complex, pointing to Ski7 as a constitutive component of the cytosolic exosome. Despite the absence of sequence homology, cytoplasmic Ski7 and nuclear Rrp6 bind Exo10 using similar surfaces and recognition motifs. Knowledge of the interacting residues in the yeast complexes allowed us to identify a splice variant of human HBS1-Like as a Ski7-like exosome-binding protein, revealing the evolutionary conservation of this cytoplasmic cofactor. PMID:27345150

  15. Nuclear proteins hijacked by mammalian cytoplasmic plus strand RNA viruses

    SciTech Connect

    Lloyd, Richard E.

    2015-05-15

    Plus strand RNA viruses that replicate in the cytoplasm face challenges in supporting the numerous biosynthetic functions required for replication and propagation. Most of these viruses are genetically simple and rely heavily on co-opting cellular proteins, particularly cellular RNA-binding proteins, into new roles for support of virus infection at the level of virus-specific translation, and building RNA replication complexes. In the course of infectious cycles many nuclear-cytoplasmic shuttling proteins of mostly nuclear distribution are detained in the cytoplasm by viruses and re-purposed for their own gain. Many mammalian viruses hijack a common group of the same factors. This review summarizes recent gains in our knowledge of how cytoplasmic RNA viruses use these co-opted host nuclear factors in new functional roles supporting virus translation and virus RNA replication and common themes employed between different virus groups. - Highlights: • Nuclear shuttling host proteins are commonly hijacked by RNA viruses to support replication. • A limited group of ubiquitous RNA binding proteins are commonly hijacked by a broad range of viruses. • Key virus proteins alter roles of RNA binding proteins in different stages of virus replication.

  16. Nuclear repulsion enables division autonomy in a single cytoplasm

    PubMed Central

    Anderson, Cori A.; Eser, Umut; Korndorf, Therese; Borsuk, Mark E.; Skotheim, Jan M.; Gladfelter, Amy S.

    2014-01-01

    Summary Background Current models of cell cycle control, based on classic studies of fused cells, predict that nuclei in a shared cytoplasm respond to the same CDK activities to undergo synchronous cycling. However, synchrony is rarely observed in naturally occurring syncytia, such as the multinucleate fungus Ashbya gossypii. In this system, nuclei divide asynchronously raising the question of how nuclear timing differences are maintained despite sharing a common milieu. Results We observe that neighboring nuclei are highly variable in division cycle duration and neighbors repel one another to space apart and demarcate their own cytoplasmic territories. The size of these territories increases as a nucleus approaches mitosis and can influence cycling rates. This non-random nuclear spacing is regulated by microtubules and is required for nuclear asynchrony, as nuclei that transiently come in very close proximity will partially synchronize. Sister nuclei born of the same mitosis are generally not persistent neighbors over their lifetimes yet remarkably retain similar division cycle times. This indicates that nuclei carry a memory of their birth state that influences their division timing and supports that nuclei subdivide a common cytosol into functionally distinct yet mobile compartments. Conclusions These findings support that nuclei use cytoplasmic microtubules to establish “cells within cells.” Individual compartments appear to push against one another to compete for cytoplasmic territory and insulate the division cycle. This provides a mechanism by which syncytial nuclei can spatially organize cell cycle signaling and suggests size control can act in a system without physical boundaries. PMID:24094857

  17. Method for Confirming Cytoplasmic Delivery of RNA Aptamers

    PubMed Central

    Dickey, David D; Dassie, Justin P; Giangrande, Paloma H

    2016-01-01

    RNA aptamers are single-stranded RNA oligos that represent a powerful emerging technology with potential for treating numerous diseases. More recently, cell-targeted RNA aptamers have been developed for delivering RNA interference (RNAi) modulators (siRNAs and miRNAs) to specific diseased cells (e.g., cancer cells or HIV infected cells) in vitro and in vivo. However, despite initial promising reports, the broad application of this aptamer delivery technology awaits the development of methods that can verify and confirm delivery of aptamers to the cytoplasm of target cells where the RNAi machinery resides. We recently developed a functional assay (RIP assay) to confirm cellular uptake and subsequent cytoplasmic release of an RNA aptamer which binds to a cell surface receptor expressed on prostate cancer cells (PSMA). To assess cytoplasmic delivery, the aptamer was chemically conjugated to saporin, a ribosome inactivating protein toxin that is toxic to cells only when delivered to the cytoplasm (where it inhibits the ribosome) by a cell-targeting ligand (e.g., aptamer). Here, we describe the chemistry used to conjugate the aptamer to saporin and discuss a gel-based method to verify conjugation efficiency. We also detail an in vitro functional assay to confirm that the aptamer retains function following conjugation to saporin and describe a cellular assay to measure aptamer-mediated saporin-induced cytotoxicity. PMID:26472453

  18. Experimental Analysis of Cell Function Using Cytoplasmic Streaming

    ERIC Educational Resources Information Center

    Janssens, Peter; Waldhuber, Megan

    2012-01-01

    This laboratory exercise investigates the phenomenon of cytoplasmic streaming in the fresh water alga "Nitella". Students use the fungal toxin cytochalasin D, an inhibitor of actin polymerization, to investigate the mechanism of streaming. Students use simple statistical methods to analyze their data. Typical student data are provided. (Contains 3…

  19. Tubulin tail sequences and post-translational modifications regulate closure of mitochondrial voltage-dependent anion channel (VDAC).

    PubMed

    Sheldon, Kely L; Gurnev, Philip A; Bezrukov, Sergey M; Sackett, Dan L

    2015-10-30

    It was previously shown that tubulin dimer interaction with the mitochondrial outer membrane protein voltage-dependent anion channel (VDAC) blocks traffic through the channel and reduces oxidative metabolism and that this requires the unstructured anionic C-terminal tail peptides found on both α- and β-tubulin subunits. It was unclear whether the α- and β-tubulin tails contribute equally to VDAC blockade and what effects might be due to sequence variations in these tail peptides or to tubulin post-translational modifications, which mostly occur on the tails. The nature of the contribution of the tubulin body beyond acting as an anchor for the tails had not been clarified either. Here we present peptide-protein chimeras to address these questions. These constructs allow us to easily combine a tail peptide with different proteins or combine different tail peptides with a particular protein. The results show that a single tail grafted to an inert protein is sufficient to produce channel closure similar to that observed with tubulin. We show that the β-tail is more than an order of magnitude more potent than the α-tail and that the lower α-tail activity is largely due to the presence of a terminal tyrosine. Detyrosination activates the α-tail, and activation is reversed by the removal of the glutamic acid penultimate to the tyrosine. Nitration of tyrosine reverses the tyrosine inhibition of binding and even induces prolonged VDAC closures. Our results demonstrate that small changes in sequence or post-translational modification of the unstructured tails of tubulin result in substantial changes in VDAC closure. PMID:26306046

  20. Ion populations in the tail of Venus

    NASA Technical Reports Server (NTRS)

    Vaisberg, O.; Fedorov, A.; Dunjushkin, F.; Kozhukhovsky, A.; Smirnov, V.; Avanov, L.; Russell, C. T.; Luhmann, J. G.

    1995-01-01

    Plasma measurements in the tails of Venus showed the existence of several ion populations. Measurements performed on Venera and Pioneer Venus spacecraft at different planetocentric distances showed the evolution of the plasma parameters along the tail. Low-energy ion fluxes measured in the tail at close downstream distances, are also observed farther downstream, and show low acceleration from 0.5 R(sub V) to 12 R(sub V). High energy ions (energetic O(+) ions) reported from Pioneer Venus Orbiter (PVO) observations in the tail at 10-12 R(sub V) seem to be the same ion component that was observed as energetic ions at the tail boundary close to the planet on Venera spacecraft. We give evidence that these ions are accelerated in the narrow shear layer near the tail boundary.

  1. Mapping mine tailings using airborne geophysical and hyperspectral remote sensing data

    NASA Astrophysics Data System (ADS)

    Shang, Jiali

    Mine tailings are the waste products from mining operations. Most mine tailings contain a considerable amount of reactive sulphides which can cause acid mine drainage (AMD) when exposed to air and water. AMD constitutes a threat both to the environment and to public health. Increased awareness of AMD has led to growing activities in mine-tailing monitoring and reclamation worldwide. Mining companies in Canada are required to provide information to provincial governments about their waste disposal and control activities. There is an urgent need to develop new automated ways to provide information on short- to long-term evolution of tailings, thus enabling the mining companies to monitor their tailings more effectively. The overall goal of the thesis is to explore the potential of hyperspectral remote sensing and geophysical techniques for mapping variations within and immediately outside of the tailings. Data used for this study are from three sources: airborne geophysical data, hyperspectral casi and Probe-1 data, and field data. This study has contributed to both the remote sensing data analysis techniques and the understanding of mine-tailing surface and subsurface processes. Specifically, this study has the following important findings: (1) Airborne magnetic and electromagnetic data can provide information regarding the subsurface distribution of mine tailings on the basis of sulphide mineral content. A procedure has been developed in this study to use these data sources for rapidly surveying large tailings areas. This procedure can minimize expenditures for mining companies when designing remedial plans for the closure of the mines. This study has also identified regions of enhanced conductivity that extend beyond the tailing containment area. This information indicates seepage pathways, and is important for monitoring the effectiveness of tailing containment structures. (2) High-spatial-resolution hyperspectral casi (Compact Airborne Spectrographic Imagery

  2. Effects of altered cytoplasmic domains on transport of the vesicular stomatitis virus glycoprotein are transferable to other proteins.

    PubMed Central

    Guan, J L; Ruusala, A; Cao, H; Rose, J K

    1988-01-01

    Alterations of the cytoplasmic domain of the vesicular stomatitis virus glycoprotein (G protein) were shown previously to affect transport of the protein from the endoplasmic reticulum, and recent studies have shown that this occurs without detectable effects on G protein folding and trimerization (R. W. Doms et al., J. Cell Biol., in press). Deletions within this domain slowed exit of the mutant proteins from the endoplasmic reticulum, and replacement of this domain with a foreign 12-amino-acid sequence blocked all transport out of the endoplasmic reticulum. To extend these studies, we determined whether such effects of cytoplasmic domain changes were transferable to other proteins. Three different assays showed that the effects of the mutations on transport of two membrane-anchored secretory proteins were the same as those observed with vesicular stomatitis virus G protein. In addition, possible effects on oligomerization were examined for both transported and nontransported forms of membrane-anchored human chorionic gonadotropin-alpha. These membrane-anchored forms, like the nonanchored human chorionic gonadotropin-alpha, had sedimentation coefficients consistent with a monomeric structure. Taken together, our results provide strong evidence that these cytoplasmic mutations affect transport by affecting interactions at or near the cytoplasmic side of the membrane. Images PMID:2841589

  3. Gravity-dependent polarity of cytoplasmic streaming in Nitellopsis

    NASA Technical Reports Server (NTRS)

    Wayne, R.; Staves, M. P.; Leopold, A. C.

    1990-01-01

    The internodal cells of the characean alga Nitellopsis obtusa were chosen to investigate the effect of gravity on cytoplasmic streaming. Horizontal cells exhibit streaming with equal velocities in both directions, whereas in vertically oriented cells, the downward-streaming cytoplasm flows ca. 10% faster than the upward-streaming cytoplasm. These results are independent of the orientation of the morphological top and bottom of the cell. We define the ratio of the velocity of the downward- to the upward-streaming cytoplasm as the polar ratio (PR). The normal polarity of a cell can be reversed (PR < 1) by treatment with neutral red (NR). The NR effect may be the result of membrane hyperpolarization, caused by the opening of K+ channels. The K+ channel blocker TEA Cl- inhibits the NR effect. External Ca2+ is required for normal graviresponsiveness. The [Ca2+] of the medium determines the polarity of cytoplasmic streaming. Less than 1 micromole Ca2+ resulted in a PR < 1 while greater than 1 micromole Ca2+ resulted in the normal gravity response. The voltage-dependent Ca(2+)-channel blocker, nifedipine, inhibited the gravity response in a reversible manner, while treatment with LaCl3 resulted in a PR < 1, indicating the presence of two types of Ca2+ channels. A new model for graviperception is presented in which the whole cell acts as the gravity sensor, and the plasma membrane acts as the gravireceptor. This is supported by ligation and UV irradiation experiments which indicate that the membranes at both ends of the cell are required for graviperception. The density of the external medium also affects the PR of Nitellopsis. Calculations are presented that indicate that the weight of the protoplasm may provide enough potential energy to open ion channels.

  4. Plant and soil reactions to nickel ore processed tailings

    SciTech Connect

    Sheets, P.J.; Volk, V.V.; Gardner, E.H.

    1982-07-01

    Greenhouse and laboratory experiments were conducted to determine the effect that tailings, produced during the processing of nickeliferous laterite ores by a proposed U.S. Bureau of Mines Process, would have on plant growth and soil properties. The tailings contained soluble salts (7.6 mmhos/cm), NH/sub 4/-N (877 ..mu..g/g), Ni (0.28%), Mn (82 ..mu..g/g DTPA-extractable), Cr (0.44%), P (2 and 6 ..mu..g/g acid F- and NaHCO/sub 3/-extractable, respectively), and Ca and Mg (1.0 and 20.7 meq/100 g NH/sub 4/Ac-extractable, respectively). Water leaching decreased the NH/sub 4/-N concentration to 53 ..mu..g/g and the EC to 0.4 mmhos/cm by removal of (NH/sub 4/)/sub 2/SO/sub 4/ and MgSO/sub 4/ salts. Tall fescue (Festuca arundinacea Schreb.) was grown on Eightlar clay soil (skeletal, serpentinitic, mesic Typic Xerochrept) amended with 0, 223, 446, and 669 g tailings/kg soil and pure, unleached tailings for 32 weeks in the greenhouse. Seedling establishment of plants grown on soil amended at the highest tailings rate and the pure tailings was initially slow, but plants grown on soil amended at lower rates established readily and grew well. Plant P was <0.24%, while plant Ca concentrations were <0.45% throughout the growth period even though Ca(H/sub 2/PO/sub 2/)/sub 2/ and gypsum had been added. Ammonium acetate-extractable Ca at the end of the growth period was <5.0 meq/100 g on all amended soils.The Mn, Ni, and Cr concentrations of plants grown on treated soils were within normal ranges, although soil-analysis values were higher than commonly found. It is recommended that the tailings be washed to reduce NH/sub 4/-N and soluble salts prior to revegetation, and that native soil be added to the surface to reduce crusting.

  5. Active tails enhance arboreal acrobatics in geckos

    PubMed Central

    Jusufi, Ardian; Goldman, Daniel I.; Revzen, Shai; Full, Robert J.

    2008-01-01

    Geckos are nature's elite climbers. Their remarkable climbing feats have been attributed to specialized feet with hairy toes that uncurl and peel in milliseconds. Here, we report that the secret to the gecko's arboreal acrobatics includes an active tail. We examine the tail's role during rapid climbing, aerial descent, and gliding. We show that a gecko's tail functions as an emergency fifth leg to prevent falling during rapid climbing. A response initiated by slipping causes the tail tip to push against the vertical surface, thereby preventing pitch-back of the head and upper body. When pitch-back cannot be prevented, geckos avoid falling by placing their tail in a posture similar to a bicycle's kickstand. Should a gecko fall with its back to the ground, a swing of its tail induces the most rapid, zero-angular momentum air-righting response yet measured. Once righted to a sprawled gliding posture, circular tail movements control yaw and pitch as the gecko descends. Our results suggest that large, active tails can function as effective control appendages. These results have provided biological inspiration for the design of an active tail on a climbing robot, and we anticipate their use in small, unmanned gliding vehicles and multisegment spacecraft. PMID:18347344

  6. Cytoplasmic dynein crosslinks and slides anti-parallel microtubules using its two motor domains

    PubMed Central

    Tanenbaum, Marvin E; Vale, Ronald D; McKenney, Richard J

    2013-01-01

    Cytoplasmic dynein is the predominant minus-end-directed microtubule (MT) motor in most eukaryotic cells. In addition to transporting vesicular cargos, dynein helps to organize MTs within MT networks such as mitotic spindles. How dynein performs such non-canonical functions is unknown. Here we demonstrate that dynein crosslinks and slides anti-parallel MTs in vitro. Surprisingly, a minimal dimeric motor lacking a tail domain and associated subunits can cause MT sliding. Single molecule imaging reveals that motors pause and frequently reverse direction when encountering an anti-parallel MT overlap, suggesting that the two motor domains can bind both MTs simultaneously. In the mitotic spindle, inward microtubule sliding by dynein counteracts outward sliding generated by kinesin-5, and we show that a tailless, dimeric motor is sufficient to drive this activity in mammalian cells. Our results identify an unexpected mechanism for dynein-driven microtubule sliding, which differs from filament sliding mechanisms described for other motor proteins. DOI: http://dx.doi.org/10.7554/eLife.00943.001 PMID:24015359

  7. Proteins involved in the degradation of cytoplasmic mRNA in the major eukaryotic model systems

    PubMed Central

    Siwaszek, Aleksandra; Ukleja, Marta; Dziembowski, Andrzej

    2014-01-01

    The process of mRNA decay and surveillance is considered to be one of the main posttranscriptional gene expression regulation platforms in eukaryotes. The degradation of stable, protein-coding transcripts is normally initiated by removal of the poly(A) tail followed by 5’-cap hydrolysis and degradation of the remaining mRNA body by Xrn1. Alternatively, the exosome complex degrades mRNA in the 3’>5’direction. The newly discovered uridinylation-dependent pathway, which is present in many different organisms, also seems to play a role in bulk mRNA degradation. Simultaneously, to avoid the synthesis of incorrect proteins, special cellular machinery is responsible for the removal of faulty transcripts via nonsense-mediated, no-go, non-stop or non-functional 18S rRNA decay. This review is focused on the major eukaryotic cytoplasmic mRNA degradation pathways showing many similarities and pointing out main differences between the main model-species: yeast, Drosophila, plants and mammals. PMID:25483043

  8. How Cholesterol Could Be Drawn to the Cytoplasmic Leaf of the Plasma Membrane by Phosphatidylethanolamine

    PubMed Central

    Giang, Ha; Schick, M.

    2014-01-01

    In the mammalian plasma membrane, cholesterol can translocate rapidly between the exoplasmic and cytoplasmic leaves, so that its distribution between them should be given by the equality of its chemical potential in the leaves. Due to its favorable interaction with sphingomyelin, which is almost entirely in the outer leaf, one expects the great majority of cholesterol to be there also. Experimental results do not support this, implying that there is some mechanism attracting cholesterol to the inner leaf. We hypothesize that it is drawn there to reduce the bending free energy of the membrane caused by the presence of PE (phosphatidylethanolamine). It does this in two ways: first by simply diluting the amount of PE in the inner leaf, and second by ordering the tails of the PE to reduce its spontaneous curvature. Incorporating this mechanism into a model free energy for the bilayer, we find that between 50 and 60% of the total cholesterol should be in the inner leaf of human erythrocytes. PMID:25418302

  9. Molecular cloning, gene organization and expression of the human UDP-GalNAc:Neu5Acalpha2-3Galbeta-R beta1,4-N-acetylgalactosaminyltransferase responsible for the biosynthesis of the blood group Sda/Cad antigen: evidence for an unusual extended cytoplasmic domain.

    PubMed Central

    Montiel, Maria-Dolores; Krzewinski-Recchi, Marie-Ange; Delannoy, Philippe; Harduin-Lepers, Anne

    2003-01-01

    The nucleotide sequence of the short and long transcripts of beta1,4- N -acetylgalactosaminyltransferase have been submitted to the DDBJ, EMBL, GenBank(R) and GSDB Nucleotide Sequence Databases under accession nos AJ517770 and AJ517771 respectively. The human Sd(a) antigen is formed through the addition of an N -acetylgalactosamine residue via a beta1,4-linkage to a sub-terminal galactose residue substituted with an alpha2,3-linked sialic acid residue. We have taken advantage of the previously cloned mouse cDNA sequence of the UDP-GalNAc:Neu5Acalpha2-3Galbeta-R beta1,4- N -acetylgalactosaminyltransferase (Sd(a) beta1,4GalNAc transferase) to screen the human EST and genomic databases and to identify the corresponding human gene. The sequence spans over 35 kb of genomic DNA on chromosome 17 and comprises at least 12 exons. As judged by reverse transcription PCR, the human gene is expressed widely since it is detected in various amounts in almost all cell types studied. Northern blot analysis indicated that five Sd(a) beta1,4GalNAc transferase transcripts of 8.8, 6.1, 4.7, 3.8 and 1.65 kb were highly expressed in colon and to a lesser extent in kidney, stomach, ileum and rectum. The complete coding nucleotide sequence was amplified from Caco-2 cells. Interestingly, the alternative use of two first exons, named E1(S) and E1(L), leads to the production of two transcripts. These nucleotide sequences give rise potentially to two proteins of 506 and 566 amino acid residues, identical in their sequence with the exception of their cytoplasmic tail. The short form is highly similar (74% identity) to the mouse enzyme whereas the long form shows an unusual long cytoplasmic tail of 66 amino acid residues that is as yet not described for any other mammalian glycosyltransferase. Upon transient transfection in Cos-7 cells of the common catalytic domain, a soluble form of the protein was obtained, which catalysed the transfer of GalNAc residues to alpha2,3-sialylated acceptor

  10. A Tale of Two Tails: Exploring Stellar Populations in the Tidal Tails of NGC 3256

    NASA Astrophysics Data System (ADS)

    Rodruck, Michael; Charlton, Jane C.; Konstantopoulos, Iraklis

    2016-01-01

    Galaxy interactions can inject material into the intergalactic medium via violent gravitational dynamics, often visualized in tidal tails. The composition of these tails has remained a mystery, as previous studies have focused on detecting tidal features, rather than the composite material itself. We have developed an observing program using deep, multiband imaging to probe the chaotic regions of tidal tails in search for an underlying stellar population. NGC 3256's twin tidal tails serve as a case study for this new technique. Our results show color values of u - g = 1.15 and r - i = 0.08 for the Western tail, and u - g = 1.33 and r - i = 0.22 for the Eastern tail, corresponding to discrepant ages between the tails of approximately 320 Myr and 785 Myr, respectively. With the interaction age of the system measured at 400 Myr, we find the stellar light in Western tail to be dominated by disrupted star clusters formed during and after the interaction, whereas the light from the Eastern tail is dominated by a 10 Gyr population originating from the host galaxies. We fit the Eastern tail color to a Mixed Stellar Population (MSP) model comprised 94% by mass of a 10 Gyr stellar population, and 6% of a 309 Myr population. We find 52% of the bolometric flux originating from this 10 Gyr population. We also detect a blue to red color gradient in each tail, running from galactic center to tail tip. In addition to tidal tail light, we detect 29 star cluster candidates (SCCs) in the Western tail and 19 in the Eastern, with mean ages of 282 Myr and 98 Myr respectively. Interestingly, we find an excess of very blue SCCs in the Eastern tail as compared to the Western tail, marking a recent, small episode of star formation.

  11. Calreticulin-independent regulation of the platelet integrin alphaIIbbeta3 by the KVGFFKR alphaIIb-cytoplasmic motif.

    PubMed

    Reilly, Dermot; Larkin, Deirdre; Devocelle, Marc; Fitzgerald, Desmond J; Moran, Niamh

    2004-02-01

    The platelet integrin alphaIIbbeta3 alters conformation in response to platelet activation and ligand binding, although the molecular mechanisms involved are not known. We previously showed that a lipid modified peptide, corresponding to the membrane proximal 989KVGFFKR995 portion of the alphaIIb cytoplasmic tail, independently activates platelet alphaIIbbeta3. Calreticulin (CRT) is a potential integrin regulatory protein based on its interaction with the highly conserved alpha-integrin sequence KxGFFKR. We therefore examined the possible interaction of calreticulin and alphaIIbbeta3 in human platelets. We demonstrate that calreticulin in platelets is localised to the granulomere. In contrast, the known integrin-binding protein talin accumulates at the periphery of spreading platelets and colocalises with alphaIIbbeta3 during the process of adhesion. An interaction between calreticulin and alphaIIbbeta3 could not be demonstrated using co-immunoprecipitation techniques under various platelet activation states, even in the presence of covalent chemical crosslinkers. Thus, calreticulin does not functionally interact with the major integrin in human platelets. In order to identify proteins that interact with the integrin KVGFFKR motif we then used a peptide 'pull-down' assay from platelet lysates with biotinylated peptides and demonstrate that only the alphaIIb and beta3 subunits selectively and individually interact with this sequence. This interaction is divalent cation-dependent, has high-affinity, and occurs both with purified alphaIIbbeta3 complex and with electroeluted alpha and beta subunits. Thus, our data show that the conserved integrin KVGFFKR domain interacts primarily with the alpha and beta cytoplasmic tails and not with CRT in human platelets. PMID:14985176

  12. Mutants of the Rous sarcoma virus envelope glycoprotein that lack the transmembrane anchor and cytoplasmic domains: analysis of intracellular transport and assembly into virions.

    PubMed Central

    Perez, L G; Davis, G L; Hunter, E

    1987-01-01

    -infected cells contained normal levels of glycoprotein. The cytoplasmic tail of gp37 is thus not required for the assembly of envelope glycoproteins into virions. It is unlikely, therefore, that this region of gp37 interacts with viral core proteins during the selective incorporation of viral glycoproteins into the viral envelope. Images PMID:3041017

  13. Mechanodelivery of nanoparticles to the cytoplasm of living cells

    NASA Astrophysics Data System (ADS)

    Emerson, Nyssa T.; Hsia, Chih-Hao; Rafalska-Metcalf, Ilona U.; Yang, Haw

    2014-04-01

    Nanotechnology has opened up the opportunity to probe, sense, and manipulate the chemical environment of biological systems with an unprecedented level of spatiotemporal control. A major obstacle to the full realization of these novel technologies is the lack of a general, robust, and simple method for the delivery of arbitrary nanostructures to the cytoplasm of intact live cells. Here, we identify a new delivery modality, based on mechanical disruption of the plasma membrane, which efficiently mediates the delivery of nanoparticles to the cytoplasm of mammalian cells. We use two distinct execution modes, two adherent cell lines, and three sizes of semiconducting nanocrystals, or quantum dots, to demonstrate its applicability and effectiveness. As the underlying mechanism is purely physical, we anticipate that such ``mechanodelivery'' can be generalized to other modes of execution as well as to the cytoplasmic introduction of a structurally diverse array of functional nanomaterials.Nanotechnology has opened up the opportunity to probe, sense, and manipulate the chemical environment of biological systems with an unprecedented level of spatiotemporal control. A major obstacle to the full realization of these novel technologies is the lack of a general, robust, and simple method for the delivery of arbitrary nanostructures to the cytoplasm of intact live cells. Here, we identify a new delivery modality, based on mechanical disruption of the plasma membrane, which efficiently mediates the delivery of nanoparticles to the cytoplasm of mammalian cells. We use two distinct execution modes, two adherent cell lines, and three sizes of semiconducting nanocrystals, or quantum dots, to demonstrate its applicability and effectiveness. As the underlying mechanism is purely physical, we anticipate that such ``mechanodelivery'' can be generalized to other modes of execution as well as to the cytoplasmic introduction of a structurally diverse array of functional nanomaterials

  14. Cytoplasmic pH dynamics in maize pulvinal cells induced by gravity vector changes

    NASA Technical Reports Server (NTRS)

    Johannes, E.; Collings, D. A.; Rink, J. C.; Allen, N. S.; Brown, C. S. (Principal Investigator)

    2001-01-01

    In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pH(c)) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291-1298). The question arises whether pH(c) has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pH(c) in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pH(c) changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pH(c) changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pH(c) has an important role in the early signaling pathways of maize stem gravitropism.

  15. Cytoplasmic pH Dynamics in Maize Pulvinal Cells Induced by Gravity Vector Changes1[w

    PubMed Central

    Johannes, Eva; Collings, David A.; Rink, Jochen C.; Allen, Nina Strömgren

    2001-01-01

    In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pHc) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291–1298). The question arises whether pHc has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pHc in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pHc changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pHc changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pHc has an important role in the early signaling pathways of maize stem gravitropism. PMID:11553740

  16. Cytoplasmic PELP1 and ERRgamma Protect Human Mammary Epithelial Cells from Tam-Induced Cell Death

    PubMed Central

    Girard, Brian J.; Regan Anderson, Tarah M.; Welch, Siya Lem; Nicely, Julie; Seewaldt, Victoria L.; Ostrander, Julie H.

    2015-01-01

    Tamoxifen (Tam) is the only FDA-approved chemoprevention agent for pre-menopausal women at high risk for developing breast cancer. While Tam reduces a woman's risk of developing estrogen receptor positive (ER+) breast cancer, the molecular mechanisms associated with risk reduction are poorly understood. Prior studies have shown that cytoplasmic proline, glutamic acid and leucine rich protein 1 (PELP1) promotes Tam resistance in breast cancer cell lines. Herein, we tested for PELP1 localization in breast epithelial cells from women at high risk for developing breast cancer and found that PELP1 was localized to the cytoplasm in 36% of samples. In vitro, immortalized HMECs expressing a nuclear localization signal (NLS) mutant of PELP1 (PELP1-cyto) were resistant to Tam-induced death. Furthermore, PELP1-cyto signaling through estrogen-related receptor gamma (ERRγ) promoted cell survival in the presence of Tam. Overexpression of ERRγ in immortalized HMECs protected cells from Tam-induced death, while knockdown of ERRγ sensitized PELP1-cyto expressing HMECs to Tam. Moreover, Tam-induced HMEC cell death was independent of apoptosis and involved accumulation of the autophagy marker LC3-II. Expression of PELP1-cyto and ERRγ reduced Tam-induced LC3-II accumulation, and knockdown of ERRγ increased LC3-II levels in response to Tam. Additionally, PELP1-cyto expression led to the upregulation of MMP-3 and MAOB, known PELP1 and ERRγ target genes, respectively. Our data indicate that cytoplasmic PELP1 induces signaling pathways that converge on ERRγ to promote cell survival in the presence of Tam. These data suggest that PELP1 localization and/or ERRγ activation could be developed as tissue biomarkers for Tam responsiveness. PMID:25789479

  17. Cytoplasmic PELP1 and ERRgamma protect human mammary epithelial cells from Tam-induced cell death.

    PubMed

    Girard, Brian J; Regan Anderson, Tarah M; Welch, Siya Lem; Nicely, Julie; Seewaldt, Victoria L; Ostrander, Julie H

    2015-01-01

    Tamoxifen (Tam) is the only FDA-approved chemoprevention agent for pre-menopausal women at high risk for developing breast cancer. While Tam reduces a woman's risk of developing estrogen receptor positive (ER+) breast cancer, the molecular mechanisms associated with risk reduction are poorly understood. Prior studies have shown that cytoplasmic proline, glutamic acid and leucine rich protein 1 (PELP1) promotes Tam resistance in breast cancer cell lines. Herein, we tested for PELP1 localization in breast epithelial cells from women at high risk for developing breast cancer and found that PELP1 was localized to the cytoplasm in 36% of samples. In vitro, immortalized HMECs expressing a nuclear localization signal (NLS) mutant of PELP1 (PELP1-cyto) were resistant to Tam-induced death. Furthermore, PELP1-cyto signaling through estrogen-related receptor gamma (ERRγ) promoted cell survival in the presence of Tam. Overexpression of ERRγ in immortalized HMECs protected cells from Tam-induced death, while knockdown of ERRγ sensitized PELP1-cyto expressing HMECs to Tam. Moreover, Tam-induced HMEC cell death was independent of apoptosis and involved accumulation of the autophagy marker LC3-II. Expression of PELP1-cyto and ERRγ reduced Tam-induced LC3-II accumulation, and knockdown of ERRγ increased LC3-II levels in response to Tam. Additionally, PELP1-cyto expression led to the upregulation of MMP-3 and MAOB, known PELP1 and ERRγ target genes, respectively. Our data indicate that cytoplasmic PELP1 induces signaling pathways that converge on ERRγ to promote cell survival in the presence of Tam. These data suggest that PELP1 localization and/or ERRγ activation could be developed as tissue biomarkers for Tam responsiveness. PMID:25789479

  18. Leaching of molybdenum and arsenic from uranium ore and mill tailings

    USGS Publications Warehouse

    Landa, E.R.

    1984-01-01

    A sequential, selective extraction procedure was used to assess the effects of sulfuric acid milling on the geochemical associations of molybdenum and arsenic in a uranium ore blend, and the tailings derived therefrom. The milling process removed about 21% of the molybdenum and 53% of the arsenic initially present in the ore. While about one-half of the molybdenum in the ore was water soluble, only about 14% existed in this form in the tailings. The major portion of the extractable molybdenum in the tailings appears to be associated with hydrous oxides of iron, and with alkaline earth sulfate precipitates. In contrast with the pattern seen for molybdenum, the partitioning of arsenic into the various extractable fractions differs little between the ore and the tailings. ?? 1984.

  19. Interaction of Uranium Mill Tailings Leachate with Soils and Clay Liners

    SciTech Connect

    Gee, G. W.; Campbell, A. C.; Sherwood, D. R.; Strickert, R. G.; Phillips, S. J.

    1980-06-01

    This study evaluates leachate-soil interactions that will take place at the Morton Ranch for certain disposal alternatives. Laboratory tests were conducted to evaluate the following: 1) physical and chemical characteristics of geologic materials from the Morton Ranch. 2) physical and chemical characteristics of acid leach tailings and tallings solution, 3) leaching tests with selected tailings materials and leach solutions to evaluate the leachability of contaminants with time under specific disposal alternatives, 4) adsorption studies measuring the sorption characteristics of heavy metals and radionuclides on the geologic materials at Morton Ranch, 5) clay liner stability tests to evaluate effects of acid leachate on clay mineralogy and clay permeability.

  20. Molecular Basis for the Anchoring of Proto-Oncoprotein Nup98 to the Cytoplasmic Face of the Nuclear Pore Complex

    PubMed Central

    Stuwe, Tobias T.; von Borzyskowski, Lennart Schada; Davenport, Andrew M.; Hoelz, André

    2014-01-01

    The cytoplasmic filament nucleoporins of the nuclear pore complex (NPC) are critically involved in nuclear export and remodeling of mRNA ribonucleoprotein particles and are associated with various human malignancies. Here, we report the crystal structure of the Nup98 C-terminal autoproteolytic domain, frequently missing from leukemogenic forms of the protein, in complex with the N-terminal domain of Nup82 and the C-terminal tail fragment of Nup159. The Nup82 β propeller serves as a non-cooperative binding platform for both binding partners. Interaction of Nup98 with Nup82 occurs through a reciprocal exchange of loop structures. Strikingly, the same Nup98 groove promiscuously interacts with Nup82 and Nup96 in a mutually excusive fashion. Simultaneous disruption of both Nup82 interactions in yeast causes severe defects in mRNA export, while the severing of a single interaction is tolerated. Thus, the cytoplasmic filament network of the NPC is robust, consistent with its essential function in nucleocytoplasmic transport. PMID:22480613

  1. Alternative waste residue materials for passive in situ prevention of sulfide-mine tailings oxidation: A field evaluation

    USGS Publications Warehouse

    Nason, Peter; Johnson, Raymond H.; Neuschutz, Clara; Alakangas, Lena; Ohlander, Bjorn

    2014-01-01

    Novel solutions for sulfide-mine tailings remediation were evaluated in field-scale experiments on a former tailings repository in northern Sweden. Uncovered sulfide-tailings were compared to sewage-sludge biosolid amended tailings over 2 years. An application of a 0.2 m single-layer sewage-sludge amendment was unsuccessful at preventing oxygen ingress to underlying tailings. It merely slowed the sulfide-oxidation rate by 20%. In addition, sludge-derived metals (Cu, Ni, Fe, and Zn) migrated and precipitated at the tailings-to-sludge interface. By using an additional 0.6 m thick fly-ash sealing layer underlying the sewage sludge layer, a solution to mitigate oxygen transport to the underlying tailings and minimize sulfide-oxidation was found. The fly-ash acted as a hardened physical barrier that prevented oxygen diffusion and provided a trap for sludge-borne metals. Nevertheless, the biosolid application hampered the application, despite the advances in the effectiveness of the fly-ash layer, as sludge-borne nitrate leached through the cover system into the underlying tailings, oxidizing pyrite. This created a 0.3 m deep oxidized zone in 6-years. This study highlights that using sewage sludge in unconventional cover systems is not always a practical solution for the remediation of sulfide-bearing mine tailings to mitigate against sulfide weathering and acid rock drainage formation.

  2. Alternative waste residue materials for passive in situ prevention of sulfide-mine tailings oxidation: a field evaluation.

    PubMed

    Nason, Peter; Johnson, Raymond H; Neuschütz, Clara; Alakangas, Lena; Öhlander, Björn

    2014-02-28

    Novel solutions for sulfide-mine tailings remediation were evaluated in field-scale experiments on a former tailings repository in northern Sweden. Uncovered sulfide-tailings were compared to sewage-sludge biosolid amended tailings over 2 years. An application of a 0.2m single-layer sewage-sludge amendment was unsuccessful at preventing oxygen ingress to underlying tailings. It merely slowed the sulfide-oxidation rate by 20%. In addition, sludge-derived metals (Cu, Ni, Fe, and Zn) migrated and precipitated at the tailings-to-sludge interface. By using an additional 0.6m thick fly-ash sealing layer underlying the sewage sludge layer, a solution to mitigate oxygen transport to the underlying tailings and minimize sulfide-oxidation was found. The fly-ash acted as a hardened physical barrier that prevented oxygen diffusion and provided a trap for sludge-borne metals. Nevertheless, the biosolid application hampered the application, despite the advances in the effectiveness of the fly-ash layer, as sludge-borne nitrate leached through the cover system into the underlying tailings, oxidizing pyrite. This created a 0.3m deep oxidized zone in 6-years. This study highlights that using sewage sludge in unconventional cover systems is not always a practical solution for the remediation of sulfide-bearing mine tailings to mitigate against sulfide weathering and acid rock drainage formation. PMID:24462894

  3. Tail reconnection triggering substorm onset.

    PubMed

    Angelopoulos, Vassilis; McFadden, James P; Larson, Davin; Carlson, Charles W; Mende, Stephen B; Frey, Harald; Phan, Tai; Sibeck, David G; Glassmeier, Karl-Heinz; Auster, Uli; Donovan, Eric; Mann, Ian R; Rae, I Jonathan; Russell, Christopher T; Runov, Andrei; Zhou, Xu-Zhi; Kepko, Larry

    2008-08-15

    Magnetospheric substorms explosively release solar wind energy previously stored in Earth's magnetotail, encompassing the entire magnetosphere and producing spectacular auroral displays. It has been unclear whether a substorm is triggered by a disruption of the electrical current flowing across the near-Earth magnetotail, at approximately 10 R(E) (R(E): Earth radius, or 6374 kilometers), or by the process of magnetic reconnection typically seen farther out in the magnetotail, at approximately 20 to 30 R(E). We report on simultaneous measurements in the magnetotail at multiple distances, at the time of substorm onset. Reconnection was observed at 20 R(E), at least 1.5 minutes before auroral intensification, at least 2 minutes before substorm expansion, and about 3 minutes before near-Earth current disruption. These results demonstrate that substorms are likely initiated by tail reconnection. PMID:18653845

  4. Tail prepivoting for the Hill estimator

    NASA Astrophysics Data System (ADS)

    Brito, Margarida; Moreira Freitas, Ana Cristina; Milhazes Freitas, Jorge

    2016-05-01

    It is well known that prepivoting reduces level error of confidence sets. We adapt this method to the context of the tail index estimation, introducing a procedure that we call tail prepivoting. We apply this procedure to the Hill estimator and establish its consistency.

  5. Fast-forward genetics by radiation hybrids to saturate the locus regulating nuclear-cytoplasmic compatibility in Triticum.

    PubMed

    Bassi, Filippo M; Ghavami, Farhad; Hayden, Matthew J; Wang, Yi; Forrest, Kerrie L; Kong, Stephan; Dizon, Rhoderissa; Michalak de Jimenez, Monika K; Meinhardt, Steven W; Mergoum, Mohamed; Gu, Yong Q; Kianian, Shahryar F

    2016-08-01

    The nuclear-encoded species cytoplasm specific (scs) genes control nuclear-cytoplasmic compatibility in wheat (genus Triticum). Alloplasmic cells, which have nucleus and cytoplasm derived from different species, produce vigorous and vital organisms only when the correct version of scs is present in their nucleus. In this study, bulks of in vivo radiation hybrids segregating for the scs phenotype have been genotyped by sequencing with over 1.9 million markers. The high marker saturation obtained for a critical region of chromosome 1D allowed identification of 3318 reads that mapped in close proximity of the scs. A novel in silico approach was deployed to extend these short reads to sequences of up to 70 Kb in length and identify candidate open reading frames (ORFs). Markers were developed to anchor the short contigs containing ORFs to a radiation hybrid map of 650 individuals with resolution of 288 Kb. The region containing the scs locus was narrowed to a single Bacterial Artificial Chromosome (BAC) contig of Aegilops tauschii. Its sequencing and assembly by nano-mapping allowed rapid identification of a rhomboid gene as the only ORF existing within the refined scs locus. Resequencing of this gene from multiple germplasm sources identified a single nucleotide mutation, which gives rise to a functional amino acid change. Gene expression characterization revealed that an active copy of this rhomboid exists on all homoeologous chromosomes of wheat, and depending on the specific cytoplasm each copy is preferentially expressed. Therefore, a new methodology was applied to unique genetic stocks to rapidly identify a strong candidate gene for the control of nuclear-cytoplasmic compatibility in wheat. PMID:26915753

  6. Historic mills and mill tailings as potential sources of contamination in and near the Humboldt River basin, northern Nevada. Chapter D.

    USGS Publications Warehouse

    Nash, J. Thomas; Stillings, Lisa L.

    2003-01-01

    Reconnaissance field studies of 40 mining districts in and near the Humboldt River basin have identified 83 mills and associated tailings impoundments and several other kinds of mineral-processing facilities (smelters, mercury retorts, heap-leach pads) related to historic mining. The majority of the mills and tailings sites are not recorded in the literature. All tailings impoundments show evidence of substantial amounts of erosion. At least 11 tailings dams were breached by flood waters, carrying fluvial tailings 1 to 15 km down canyons and across alluvial fans. Most of the tailings sites are dry most of the year, but some are near streams. Tailings that are wet for part of the year do not appear to be reacting significantly with those waters because physical factors such as clay layers and hard-pan cement appear to limit permeability and release of metals to surface waters. The major impact of mill tailings on surface- water quality may be brief flushes of runoff during storm events that carry acid and metals released from soluble mineral crusts. Small ephemeral ponds and puddles that tend to collect in trenches and low areas on tailings impoundments tend to be acidic and extremely enriched in metals, in part through cycles of evaporation. Ponded water that is rich in salts and metals could be acutely toxic to unsuspecting animals. Rare extreme storms have the potential to cause catastrophic failure of tailings impoundments, carry away metals in stormwaters, and transport tailings as debris flows for 1 to 15 km. In most situations these stormwaters and transported tailings could impact wildlife but probably would impact few or no people or domes-tic water wells. Because all identified historic tailings sites are several kilometers or more from the Humboldt River and major tributaries, tailings probably have no measurable impact on water quality in the main stem of the Humboldt River.

  7. Injurious tail biting in pigs: how can it be controlled in existing systems without tail docking?

    PubMed

    D'Eath, R B; Arnott, G; Turner, S P; Jensen, T; Lahrmann, H P; Busch, M E; Niemi, J K; Lawrence, A B; Sandøe, P

    2014-09-01

    Tail biting is a serious animal welfare and economic problem in pig production. Tail docking, which reduces but does not eliminate tail biting, remains widespread. However, in the EU tail docking may not be used routinely, and some 'alternative' forms of pig production and certain countries do not allow tail docking at all. Against this background, using a novel approach focusing on research where tail injuries were quantified, we review the measures that can be used to control tail biting in pigs without tail docking. Using this strict criterion, there was good evidence that manipulable substrates and feeder space affect damaging tail biting. Only epidemiological evidence was available for effects of temperature and season, and the effect of stocking density was unclear. Studies suggest that group size has little effect, and the effects of nutrition, disease and breed require further investigation. The review identifies a number of knowledge gaps and promising avenues for future research into prevention and mitigation. We illustrate the diversity of hypotheses concerning how different proposed risk factors might increase tail biting through their effect on each other or on the proposed underlying processes of tail biting. A quantitative comparison of the efficacy of different methods of provision of manipulable materials, and a review of current practices in countries and assurance schemes where tail docking is banned, both suggest that daily provision of small quantities of destructible, manipulable natural materials can be of considerable benefit. Further comparative research is needed into materials, such as ropes, which are compatible with slatted floors. Also, materials which double as fuel for anaerobic digesters could be utilised. As well as optimising housing and management to reduce risk, it is important to detect and treat tail biting as soon as it occurs. Early warning signs before the first bloody tails appear, such as pigs holding their tails tucked

  8. Mineralogical and geochemical characterization of arsenic in an abandoned mine tailings of Korea.

    PubMed

    Ahn, Joo Sung; Park, Young Seog; Kim, Ju-Yong; Kim, Kyoung-Woong

    2005-04-01

    The mineralogical and chemical characteristics of As solid phases in arsenic-rich mine tailings from the Nakdong As-Bi mine in Korea was investigated. The tailings generated from the ore roasting process contained 4.36% of As whereas the concentration was up to 20.2% in some tailings from the cyanidation process for the Au extraction. Thin indurated layers and other secondary precipitates had formed at the surfaces of the tailings piles and the As contents of the hardened layers varied from 2.87 to 16.0%. Scorodite and iron arsenate (Fe3AsO7) were the primary As-bearing crystalline minerals. Others such as arsenolamprite, bernardite and titanium oxide arsenate were also found. The amorphous As-Fe phases often showed framboidal aggregates and gel type textures with desiccation cracks. Sequential extraction results also showed that 55.7-91.1% of the As in tailings were NH(4)-oxalate extractable As, further confirmed the predominance of amorphous As-Fe solid phases. When the tailings were equilibrated with de-ionized water, the solution exhibited extremely acidic conditions (pH 2.01-3.10) and high concentrations of dissolved As (up to 29.5 mg L(-1)), indicating high potentials for As to be released during rainfall events. The downstream water was affected by drainage from tailings and contained 12.7-522 microg L(-1) of As. The amorphous As-Fe phases in tailings have not entirely been stabilized through the long term natural weathering processes. To remediate the environmental harms they had caused, anthropogenic interventions to stabilize or immobilize As in the tailings pile should be explored. PMID:16003582

  9. Nucleoporin Nup98 mediates galectin-3 nuclear-cytoplasmic trafficking

    SciTech Connect

    Funasaka, Tatsuyoshi; Balan, Vitaly; Raz, Avraham; Wong, Richard W.

    2013-04-26

    Highlights: •Nuclear pore protein Nup98 is a novel binding partner of galectin-3. •Nup98 transports galectin-3 into cytoplasm. •Nup98 depletion leads to galectin-3 nuclear transport and induces growth retardation. •Nup98 may involve in ß-catenin pathway through interaction with galectin-3. -- Abstract: Nucleoporin Nup98 is a component of the nuclear pore complex, and is important in transport across the nuclear pore. Many studies implicate nucleoporin in cancer progression, but no direct mechanistic studies of its effect in cancer have been reported. We show here that Nup98 specifically regulates nucleus–cytoplasm transport of galectin-3, which is a ß-galactoside-binding protein that affects adhesion, migration, and cancer progression, and controls cell growth through the ß-catenin signaling pathway in cancer cells. Nup98 interacted with galectin-3 on the nuclear membrane, and promoted galectin-3 cytoplasmic translocation whereas other nucleoporins did not show these functions. Inversely, silencing of Nup98 expression by siRNA technique localized galectin-3 to the nucleus and retarded cell growth, which was rescued by Nup98 transfection. In addition, Nup98 RNA interference significantly suppressed downstream mRNA expression in the ß-catenin pathway, such as cyclin D1 and FRA-1, while nuclear galectin-3 binds to ß-catenin to inhibit transcriptional activity. Reduced expression of ß-catenin target genes is consistent with the Nup98 reduction and the galectin-3–nucleus translocation rate. Overall, the results show Nup98’s involvement in nuclear–cytoplasm translocation of galectin-3 and ß-catenin signaling pathway in regulating cell proliferation, and the results depicted here suggest a novel therapeutic target/modality for cancers.

  10. Cytoplasmic Functions of the Tumor Suppressor p53

    PubMed Central

    Green, Douglas R.; Kroemer, Guido

    2010-01-01

    The principal tumor suppressor protein, p53, accumulates in cells in response to DNA damage, oncogene activation, and other stresses. It acts as a nuclear transcription factor that transactivates genes involved in apoptosis, cell cycle regulation, and numerous other processes. An emerging area of research unravels additional activities of p53 in the cytoplasm, where it triggers apoptosis and inhibits autophagy. These novel functions contribute to p53’s mission as a tumor suppressor. PMID:19407794

  11. Vortex Breakdown-Aircraft Tail Interaction

    NASA Astrophysics Data System (ADS)

    Kim, Younjong; Rockwell, Donald

    2003-11-01

    The interaction of vortex breakdown with the tail of an aircraft can lead to severe unsteady loading and vibration. A technique of high-image-density particle image velocimetry is employed to characterize the instantaneous and averaged structure of a broken-down vortex with a generic tail configuration. Interaction of the primary (incident) vortex with the tail results in formation of a relatively large-scale cluster of secondary vorticity. The coexistence of these primary and secondary vortical structures is intimately associated with the unsteadiness of the vortex system, and thereby the near-surface fluctuations associated with buffet loading. Instantaneous and averaged representations of the vortex-tail interaction provide insight into the complex physics. Furthermore, a low order POD model is employed to characterize the most energetic modes of the vortex-tail interaction.

  12. Detection of intra-brain cytoplasmic 1 (BC1) long noncoding RNA using graphene oxide-fluorescence beacon detector

    PubMed Central

    Kim, Mee Young; Hwang, Do Won; Li, Fangyuan; Choi, Yoori; Byun, Jung Woo; Kim, Dongho; Kim, Jee-Eun; Char, Kookheon; Lee, Dong Soo

    2016-01-01

    Detection of cellular expression of long noncoding RNAs (lncRNAs) was elusive due to the ambiguity of exposure of their reactive sequences associated with their secondary/tertiary structures and dynamic binding of proteins around lncRNAs. Herein, we developed graphene-based detection techniques exploiting the quenching capability of graphene oxide (GO) flakes for fluorescent dye (FAM)-labeled single-stranded siRNAs and consequent un-quenching by their detachment from GO by matching lncRNAs. A brain cytoplasmic 1 (BC1) lncRNA expression was significantly decreased by a siRNA, siBC1–1. GO quenched the FAM-labeled siBC1–1 peptide nucleic acid (PNA) probe, and this quenching was recovered by BC1. While FAM-siBC1–1-PNA-GO complex transfected spontaneously mouse or human neural stem cells, fluorescence was recovered only in mouse cells having high BC1 expression. Fluorescent dye-labeled single-stranded RNA-GO probe could detect the reactive exposed nucleic acid sequence of a cytoplasmic lncRNA expressing in the cytoplasm, which strategy can be used as a detection method of lncRNA expression. PMID:26997297

  13. Detection of intra-brain cytoplasmic 1 (BC1) long noncoding RNA using graphene oxide-fluorescence beacon detector.

    PubMed

    Kim, Mee Young; Hwang, Do Won; Li, Fangyuan; Choi, Yoori; Byun, Jung Woo; Kim, Dongho; Kim, Jee-Eun; Char, Kookheon; Lee, Dong Soo

    2016-01-01

    Detection of cellular expression of long noncoding RNAs (lncRNAs) was elusive due to the ambiguity of exposure of their reactive sequences associated with their secondary/tertiary structures and dynamic binding of proteins around lncRNAs. Herein, we developed graphene-based detection techniques exploiting the quenching capability of graphene oxide (GO) flakes for fluorescent dye (FAM)-labeled single-stranded siRNAs and consequent un-quenching by their detachment from GO by matching lncRNAs. A brain cytoplasmic 1 (BC1) lncRNA expression was significantly decreased by a siRNA, siBC1-1. GO quenched the FAM-labeled siBC1-1 peptide nucleic acid (PNA) probe, and this quenching was recovered by BC1. While FAM-siBC1-1-PNA-GO complex transfected spontaneously mouse or human neural stem cells, fluorescence was recovered only in mouse cells having high BC1 expression. Fluorescent dye-labeled single-stranded RNA-GO probe could detect the reactive exposed nucleic acid sequence of a cytoplasmic lncRNA expressing in the cytoplasm, which strategy can be used as a detection method of lncRNA expression. PMID:26997297

  14. Intestinal and liver morphometry of the Yellow Tail Tetra (Astyanax altiparanae) fed with oregano oil.

    PubMed

    Ferreira, Pollyanna M F; Caldas, Débora W; Salaro, Ana Lúcia; Sartori, Sirlene S R; Oliveira, Jerusa M; Cardoso, Alex J S; Zuanon, Jener A S

    2016-01-01

    This study aimed to evaluate the effect of oregano oil on the intestinal and liver morphometry of yellow tail tetra, Astyanax altiparanae. Fish (1.46 ± 0.09 g) were kept in a 60-L aquaria, at a stocking density of 0.5 fi sh L-1. Six diets containing varying amounts of oregano oil were evaluated (0.0; 0.5; 1.0; 1.5; 2.0 and 2.5 g of oregano oil kg-1). At the end of 90 days, the fi sh were euthanised. Four intestines and four livers were collected per treatment, which were fi xed in Bouin and embedded in resin. For height and width folds, the absorption surface area and thickness of the muscular layer a positive linear effect of oregano oil was observed. A decrescent linear effect on the total number of goblet cells was also observed. For the cytoplasmic percentage of hepatocytes and liver glycogen, a positive linear effect of oregano oil was observed. There was a decreasing linear effect on the percentage of nuclei in the hepatocytes and capillaries. Thus, the oregano essential oil promotes increased absorption areas, modulates the amount of goblet cells involved in protecting the intestinal mucosa and promotes cytoplasmic increase with greater deposition of liver glycogen in yellow tail tetra. PMID:27331801

  15. Olfactory mucosa ultrastructure in the short-tailed shrews, Blarina brevicauda and Blarina carolinensis.

    PubMed

    Byrum, L J; Carson, K A; Rose, R K

    2001-12-01

    The olfactory mucosae of the northern short-tailed shrew, Blarina brevicauda, and the southern short-tailed shrew, Blarina carolinensis, were examined by light and electron microscopy. A well-developed olfactory epithelium was observed that included all of the cells necessary to provide for a sensitive olfactory system, suggesting that olfaction plays a major role in the behavior of these animals. There were no significant differences between the olfactory mucosae of these two species. The general features of the olfactory epithelium in these shrews were similar to those reported for several other macrosmatic mammals. A new type of supporting cell, called the light supporting cell, was observed in these shrews. The light supporting cell cytoplasm exhibited very little staining by light microscopy and had low electron density by transmission electron microscopy compared to that of the more common dark supporting cell. The light supporting cell had a convex apical surface with microvilli and lacked the large amounts of smooth endoplasmic reticulum (SER) typical of the apical cytoplasm of the dark supporting cell. In the lamina propria of the mucosa, the Bowman's glands consisted of two cell types, one with electron-lucent, alcian blue-positive granules, and the other with electron-dense PAS-positive granules. The cell with electron-lucent granules contained large amounts of SER and small clumps of rough ER. The cells with electron-dense granules had large amounts of RER and little SER. PMID:12221510

  16. Cytoplasmic Dynamics Reveals Two Modes of Nucleoid-Dependent Mobility

    PubMed Central

    Stylianidou, Stella; Kuwada, Nathan J.; Wiggins, Paul A.

    2014-01-01

    It has been proposed that forces resulting from the physical exclusion of macromolecules from the bacterial nucleoid play a central role in organizing the bacterial cell, yet this proposal has not been quantitatively tested. To investigate this hypothesis, we mapped the generic motion of large protein complexes in the bacterial cytoplasm through quantitative analysis of thousands of complete cell-cycle trajectories of fluorescently tagged ectopic MS2-mRNA complexes. We find the motion of these complexes in the cytoplasm is strongly dependent on their spatial position along the long axis of the cell, and that their dynamics are consistent with a quantitative model that requires only nucleoid exclusion and membrane confinement. This analysis also reveals that the nucleoid increases the mobility of MS2-mRNA complexes, resulting in a fourfold increase in diffusion coefficients between regions of the lowest and highest nucleoid density. These data provide strong quantitative support for two modes of nucleoid action: the widely accepted mechanism of nucleoid exclusion in organizing the cell and a newly proposed mode, in which the nucleoid facilitates rapid motion throughout the cytoplasm. PMID:25468347

  17. Coilin Shuttles between the Nucleus and Cytoplasm In Xenopus Oocytes

    PubMed Central

    Bellini, Michel; Gall, Joseph G.

    1999-01-01

    Coiled bodies are discrete nuclear organelles often identified by the marker protein p80-coilin. Because coilin is not detected in the cytoplasm by immunofluorescence and Western blotting, it has been considered an exclusively nuclear protein. In the Xenopus germinal vesicle (GV), most coilin actually resides in the nucleoplasm, although it is highly concentrated in 50–100 coiled bodies. When affinity-purified anti-coilin antibodies were injected into the cytoplasm of oocytes, they could be detected in coiled bodies within 2–3 h. Coiled bodies were intensely labeled after 18 h, whereas other nuclear organelles remained negative. Because the nuclear envelope does not allow passive diffusion of immunoglobulins, this observation suggests that anti-coilin antibodies are imported into the nucleus as an antigen–antibody complex with coilin. Newly synthesized coilin is not required, because cycloheximide had no effect on nuclear import and subsequent targeting of the antibodies. Additional experiments with myc-tagged coilin and myc-tagged pyruvate kinase confirmed that coilin is a shuttling protein. The shuttling of Nopp140, NO38/B23, and nucleolin was easily demonstrated by the targeting of their respective antibodies to the nucleoli, whereas anti-SC35 did not enter the germinal vesicle. We suggest that coilin, perhaps in association with Nopp140, may function as part of a transport system between the cytoplasm and the coiled bodies. PMID:10512877

  18. The Interaction of Neurofilaments with the Microtubule Motor Cytoplasmic Dynein

    PubMed Central

    Wagner, Oliver I.; Ascaño, Jennifer; Tokito, Mariko; Leterrier, Jean-Francois; Janmey, Paul A.; Holzbaur, Erika L. F.

    2004-01-01

    Neurofilaments are synthesized in the cell body of neurons and transported outward along the axon via slow axonal transport. Direct observation of neurofilaments trafficking in live cells suggests that the slow outward rate of transport is due to the net effects of anterograde and retrograde microtubule motors pulling in opposition. Previous studies have suggested that cytoplasmic dynein is required for efficient neurofilament transport. In this study, we examine the interaction of neurofilaments with cytoplasmic dynein. We used fluid tapping mode atomic force microscopy to visualize single neurofilaments, microtubules, dynein/dynactin, and physical interactions between these neuronal components. AFM images suggest that neurofilaments act as cargo for dynein, associating with the base of the motor complex. Yeast two-hybrid and affinity chromatography assays confirm this hypothesis, indicating that neurofilament subunit M binds directly to dynein IC. This interaction is blocked by monoclonal antibodies directed either to NF-M or to dynein. Together these data suggest that a specific interaction between neurofilament subunit M and cytoplasmic dynein is involved in the saltatory bidirectional motility of neurofilaments undergoing axonal transport in the neuron. PMID:15342782

  19. Increased cytoplasm viscosity hampers aggregate polar segregation in Escherichia coli.

    PubMed

    Oliveira, Samuel M D; Neeli-Venkata, Ramakanth; Goncalves, Nadia S M; Santinha, João A; Martins, Leonardo; Tran, Huy; Mäkelä, Jarno; Gupta, Abhishekh; Barandas, Marilia; Häkkinen, Antti; Lloyd-Price, Jason; Fonseca, José M; Ribeiro, Andre S

    2016-02-01

    In Escherichia coli, under optimal conditions, protein aggregates associated with cellular aging are excluded from midcell by the nucleoid. We study the functionality of this process under sub-optimal temperatures from population and time lapse images of individual cells and aggregates and nucleoids within. We show that, as temperature decreases, aggregates become homogeneously distributed and uncorrelated with nucleoid size and location. We present evidence that this is due to increased cytoplasm viscosity, which weakens the anisotropy in aggregate displacements at the nucleoid borders that is responsible for their preference for polar localisation. Next, we show that in plasmolysed cells, which have increased cytoplasm viscosity, aggregates are also not preferentially located at the poles. Finally, we show that the inability of cells with increased viscosity to exclude aggregates from midcell results in enhanced aggregate concentration in between the nucleoids in cells close to dividing. This weakens the asymmetries in aggregate numbers between sister cells of subsequent generations required for rejuvenating cell lineages. We conclude that the process of exclusion of protein aggregates from midcell is not immune to stress conditions affecting the cytoplasm viscosity. The findings contribute to our understanding of E. coli's internal organisation and functioning, and its fragility to stressful conditions. PMID:26507787

  20. Genetic studies on cytoplasmic male sterility in maize

    SciTech Connect

    Laughnan, J.R.

    1992-01-01

    Our research concerns the basic mechanisms of cytoplasmic male sterility (CMS) and fertility restoration in maize. The molecular determination of CMS is in the DNA of the mitochondria (mtDNA) but specific nuclear restorer-of-fertility (Rf) genes can overrule the male-sterile effect of the cytoplasm. Our approach to the study of the Rf genes is threefold. We are attempting to tag the cms-S Rf genes and the cms-T Rf2 gene with controlling elements (CEs). Since we have identified a number of spontaneous Rf genes for cms-S and have demonstrated that they are themselves transposable, we are also searching for cases in which an Rf gene is inserted into a wild-type gene. The other aspect of our research involves the nuclear control over the organization of the mitochondrial genome. We found that the changes in mtDNA organization upon cytoplasmic reversion to fertility were characteristic of the nuclear background in which the reversion event occurred. We have investigated whether these differences are a reflection of differences in the organization of the mtDNA genome before reversion.

  1. Female breast carcinomas: nuclear and cytoplasmic proteins versus steroid receptors.

    PubMed

    Bryś, M; Romanowicz-Makowska, H; Nawrocka, A; Krajewska, W M

    2000-01-01

    Nuclear and cytoplasmic proteins of human female breast cancer were analysed by one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Oestrogen receptor and progesterone receptor expression was determined by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. The electropherograms were developed by silver nitrate staining and quantitative analysis was carried out by video densitometer using the software Gel-Pro Analyzer. Nuclear and cytoplasmic proteins of breast carcinomas and normal tissue differed both qualitatively and quantitatively. Nuclear polypeptides of 108, 53 and 48 kD as well as the 36 kD cytoplasmic polypeptide were specific for tumour samples, while the 51 kD nuclear polypeptide was detected only in normal tissue. Quantitative differences in band density were noted in the 32 kD nuclear polypeptide. This polypeptide was expressed in greatest concentration in infiltrating ductal carcinomas which also indicated the greatest oestrogen receptor gene expression. This relationship appeared to be statistically significant (p < 0.005). No correlations were evident between the 32 kD protein expression and the progesterone receptor gene expression in any of the tissue types examined, nor between the 32 kD protein and the patient's age or tumour grade. PMID:10756981

  2. Predominantly Cytoplasmic Localization in Yeast of ASR1, a Non-Receptor Transcription Factor from Plants

    PubMed Central

    Urtasun, Nicolás; Correa García, Susana; Iusem, Norberto D; Bermúdez Moretti, Mariana

    2010-01-01

    The Asr gene family (named after abscisic acid, stress and ripening), currently classified as a novel group of the LEA superfamily, is exclusively present in the genomes of seed plants, except for the Brassicaceae family. It is associated with water-deficit stress and is involved in adaptation to dry climates. Motivated by separate reports depicting ASR proteins as either transcription factors or chaperones, we decided to determine the intracellular localization of ASR proteins. For that purpose, we employed an in vivo eukaryotic expression system, the heterologous model Saccharomyces cerevisiae, including wild type strains as well as mutants in which the variant ASR1 previously proved to be functionally protective against osmotic stress. Our methodology involved immunofluorescence-based confocal microscopy, without artificially altering the native structure of the protein under study. Results show that, in both normal and osmotic stress conditions, recombinant ASR1 turned out to localize mainly to the cytoplasm, irrespective of the genotype used, revealing a scattered distribution in the form of dots or granules. The results are discussed in terms of a plausible dual (cytoplasmic and nuclear) role of ASR proteins. PMID:20657719

  3. Most Human Proteins Made in Both Nucleus and Cytoplasm Turn Over within Minutes

    PubMed Central

    Baboo, Sabyasachi; Bhushan, Bhaskar; Jiang, Haibo; Grovenor, Chris R. M.; Pierre, Philippe; Davis, Benjamin G.; Cook, Peter R.

    2014-01-01

    In bacteria, protein synthesis can be coupled to transcription, but in eukaryotes it is believed to occur solely in the cytoplasm. Using pulses as short as 5 s, we find that three analogues – L-azidohomoalanine, puromycin (detected after attaching fluors using ‘click’ chemistry or immuno-labeling), and amino acids tagged with ‘heavy’ 15N and 13C (detected using secondary ion mass spectrometry) – are incorporated into the nucleus and cytoplasm in a process sensitive to translational inhibitors. The nuclear incorporation represents a significant fraction of the total, and labels in both compartments have half-lives of less than a minute; results are consistent with most newly-made peptides being destroyed soon after they are made. As nascent RNA bearing a premature termination codon (detected by fluorescence in situ hybridization) is also eliminated by a mechanism sensitive to a translational inhibitor, the nuclear turnover of peptides is probably a by-product of proof-reading the RNA for stop codons (a process known as nonsense-mediated decay). We speculate that the apparently-wasteful turnover of this previously-hidden (‘dark-matter’) world of peptide is involved in regulating protein production. PMID:24911415

  4. Vortex control for tail buffet alleviation on a twin-tail fighter configuration

    NASA Technical Reports Server (NTRS)

    Rao, Dhanvada M.; Puram, C. K.; Shah, Gautam H.

    1989-01-01

    Two aerodynamic concepts proposed for alleviating high-alpha tail buffet characteristics of a LEX (Leading Edge Extension) vortex dominated twin-tail fighter configuration were explored in low-speed tunnel tests on generic models via flow visualizations, 6-component balance measurements and monitoring of tail dynamics. Passive dorsal-fin extensions of the vertical tails, and an active LEX arrangement with up-deflected edge sections were evaluated as independent means of re-structuring the adverse vortical flow environment in the tail region. Each of these techniques successfully reduced the buffet as measured by the root-mean-square of tail accelerometer output, particularly at post-stall angles of attack when the baseline configuration was characterized by high buffet intensity. Used in combination, the two concepts indicated significant tail buffet relief with relatively minor impact on the high-alpha configuration aerodynamics.

  5. Partial structural characterization of the cytoplasmic domain of the erythrocyte membrane protein, band 3.

    PubMed

    Appell, K C; Low, P S

    1981-11-10

    The cytoplasmic domain of band 3 was released from spectrin-depleted, acetic acid-stripped erythrocyte membrane vesicles by mild chymotryptic digestion. After purification by ion exchange and gel filtration chromatography, the fragment preparation was found to be greater than 90% pure on polyacrylamide disc gels in the presence of 0.2% sodium dodecyl sulfate. The subunit Mr from the electrophoretic procedure was estimated at approximately 40,000. The isolated cytoplasmic fragment ws judged to be a dimer, since (i) the unmodified fragment and its disulfide-cross-linked (dimeric) counterpart eluted in the same peak fraction from a Sephacryl S-200 gel filtration column, and (ii) the sedimentation velocity molecular weight of the native fragment was calculated to be approximately 95,000. No evidence of either larger or smaller aggregates was obtained. The frictional ratio of the fragment was measured at 1.6, suggesting a highly elongated morphology. The circular dichroism spectrum of the fragment corresponded to approximately 37% alpha helix. Titration of the cytoplasmic fragment over the physiological pH range gave rise to a reversible 2-fold increase in the intrinsic fluorescence quantum yield (lambda ex, 290 nm; lambda em, 335 nm) between pH 6 and 9. Computer analysis of the data yielded a temperature-dependent apparent pKa of 7.8 at 37 degrees C and 8.1 at 20 degrees C, both with Hill coefficients less than or equal to 1. Calorimetric experiments revealed a similar sensitivity to pH, where the denaturation temperature of the fragment titrated from 74 degrees C at pH 6 to 59 degrees C at pH 8.5, with an apparent pKa of 7.3 and a Hill coefficient less than 1. The enthalpies and widths at half-height of the transitions were also exquisitely sensitive to pH. The fluorescence and calorimetric data could all be described by the titration of a single ionizable group of apparent pKa of 7.8 at 37 degrees C and delta pKa/degrees C of -0.018. The ionization of this critical

  6. Significance of Microbial Communities and Interactions in Safeguarding Reactive Mine Tailings by Ecological Engineering▿†

    PubMed Central

    N̆ancucheo, Ivan; Johnson, D. Barrie

    2011-01-01

    Pyritic mine tailings (mineral waste generated by metal mining) pose significant risk to the environment as point sources of acidic, metal-rich effluents (acid mine drainage [AMD]). While the accelerated oxidative dissolution of pyrite and other sulfide minerals in tailings by acidophilic chemolithotrophic prokaryotes has been widely reported, other acidophiles (heterotrophic bacteria that catalyze the dissimilatory reduction of iron and sulfur) can reverse the reactions involved in AMD genesis, and these have been implicated in the “natural attenuation” of mine waters. We have investigated whether by manipulating microbial communities in tailings (inoculating with iron- and sulfur-reducing acidophilic bacteria and phototrophic acidophilic microalgae) it is possible to mitigate the impact of the acid-generating and metal-mobilizing chemolithotrophic prokaryotes that are indigenous to tailing deposits. Sixty tailings mesocosms were set up, using five different microbial inoculation variants, and analyzed at regular intervals for changes in physicochemical and microbiological parameters for up to 1 year. Differences between treatment protocols were most apparent between tailings that had been inoculated with acidophilic algae in addition to aerobic and anaerobic heterotrophic bacteria and those that had been inoculated with only pyrite-oxidizing chemolithotrophs; these differences included higher pH values, lower redox potentials, and smaller concentrations of soluble copper and zinc. The results suggest that empirical ecological engineering of tailing lagoons to promote the growth and activities of iron- and sulfate-reducing bacteria could minimize their risk of AMD production and that the heterotrophic populations could be sustained by facilitating the growth of microalgae to provide continuous inputs of organic carbon. PMID:21965397

  7. Shake a tail feather: the evolution of the theropod tail into a stiff aerodynamic surface.

    PubMed

    Pittman, Michael; Gatesy, Stephen M; Upchurch, Paul; Goswami, Anjali; Hutchinson, John R

    2013-01-01

    Theropod dinosaurs show striking morphological and functional tail variation; e.g., a long, robust, basal theropod tail used for counterbalance, or a short, modern avian tail used as an aerodynamic surface. We used a quantitative morphological and functional analysis to reconstruct intervertebral joint stiffness in the tail along the theropod lineage to extant birds. This provides new details of the tail's morphological transformation, and for the first time quantitatively evaluates its biomechanical consequences. We observe that both dorsoventral and lateral joint stiffness decreased along the non-avian theropod lineage (between nodes Theropoda and Paraves). Our results show how the tail structure of non-avian theropods was mechanically appropriate for holding itself up against gravity and maintaining passive balance. However, as dorsoventral and lateral joint stiffness decreased, the tail may have become more effective for dynamically maintaining balance. This supports our hypothesis of a reduction of dorsoventral and lateral joint stiffness in shorter tails. Along the avian theropod lineage (Avialae to crown group birds), dorsoventral and lateral joint stiffness increased overall, which appears to contradict our null expectation. We infer that this departure in joint stiffness is specific to the tail's aerodynamic role and the functional constraints imposed by it. Increased dorsoventral and lateral joint stiffness may have facilitated a gradually improved capacity to lift, depress, and swing the tail. The associated morphological changes should have resulted in a tail capable of producing larger muscular forces to utilise larger lift forces in flight. Improved joint mobility in neornithine birds potentially permitted an increase in the range of lift force vector orientations, which might have improved flight proficiency and manoeuvrability. The tail morphology of modern birds with tail fanning capabilities originated in early ornithuromorph birds. Hence, these

  8. Cytoplasmic calcium buffers in intact human red cells.

    PubMed Central

    Tiffert, T; Lew, V L

    1997-01-01

    1. Precise knowledge of the cytoplasmic Ca2+ buffering behaviour in intact human red cells is essential for the characterization of their [Ca2+]i-dependent functions. This was investigated by using a refined method and experimental protocols which allowed continuity in the estimates of [Ca2+]i, from nanomolar to millimolar concentrations, in the presence and absence of external Ca2+ chelators. 2. The study was carried out in human red cells whose plasma membrane Ca2+ pump was inhibited either by depleting the cells of ATP or by adding vanadate to the cell suspension. Cytoplasmic Ca2+ buffering was analysed from plots of total cell calcium content vs. ionized cytoplasmic Ca2+ concentration ([CaT]i vs. [Ca2+]i) obtained from measurements of the equilibrium distribution of 45Ca2+ at different external Ca2+ concentrations ([Ca2+]o), in conditions known to clamp cell volume and pH. The equilibrium distribution of 45Ca2+ was induced by the divalent cation ionophore A23187. 3. The results showed the following. (i) The known red cell Ca2+ buffer represented by alpha, with a large capacity and low Ca2+ affinity, was the main cytoplasmic Ca2+ binding agent. (ii) The value of alpha was remarkably constant; the means for each of four donors ranged from 0.33 to 0.35, with a combined value of all independent measurements of 0.34 +/- 0.01 (mean +/- S.E.M., n = 16). This contrasts with the variability previously reported. (iii) There was an additional Ca2+ buffering complex with a low capacity (approximately 80 micromol (340 g Hb)(-1)) and intermediate Ca2+ affinity (apparent dissociation constant, K(D,app) approximately 4-50 microM) whose possible identity is discussed. (iv) The cell content of putative Ca2+ buffers with submicromolar Ca2+ dissociation constants was below the detection limit of the methods used here (less than 2 micromol (340 g Hb)(-1)). 4. Vanadate (1 mM) inhibited the Vmax of the Ca2+ pump in inosine-fed cells by 99.7%. The cytoplasmic Ca2+ buffering behaviour

  9. Aquatic impact investigation from the Lynn Lake tailings: Status report, 1998. Report number 98-09

    SciTech Connect

    Green, D.J.

    1998-12-31

    Mining activity in the vicinity of Lynn Lake in north-west Manitoba resulted in development of a number of tailings ponds that are potential sources of acid drainage. Observations such as the presence of dead trees in the vicinity of tailings pond dikes and a distinctive green coloration in one effluent pond raised concerns that confinement of acid drainage in the tailings area may be compromised and causing renewed detrimental impacts to the Lynn River and surrounding area. This report presents results of water quality and sediment surveys conducted in the Lynn Lake area. Parameters studied include pH, conductivity, calcium, sulfate, iron, nickel, zinc, copper, cyanide, and presence of benthos. Comparisons of the results are made with results from earlier surveys in order to determine temporal trends.

  10. Wind-tunnel Investigation of End-plate Effects of Horizontal Tails on a Vertical Tail Compared with Available Theory

    NASA Technical Reports Server (NTRS)

    Murray, Harry E

    1946-01-01

    A vertical-tail model with stub fuselage was tested in combination with various simulated horizontal tails to determine the effect of horizontal-tail span and location on the aerodynamic characteristics of the vertical tail. Available theoretical data on end-plate effects were collected and presented in the form most suitable for design purposes. Reasonable agreement was obtained between the measured and theoretical end-plate effects of horizontal tails on vertical tails, and the data indicated that the end-plate effect was determined more by the location of the horizontal tail than by the span of the horizontal tail. The horizontal tail gave most end-plate effect when located near either tip of the vertical tail and, when located near the base of the vertical tail, the end-plate effect was increased by moving the horizontal tail rearward.

  11. Thermal stabilization of uranium mill tailings

    SciTech Connect

    Dreesen, D.R.; Williams, J.M.; Cokal, E.J.

    1981-01-01

    The sintering of tailings at high temperatures (1200/sup 0/C) has shown promise as a conditioning approach that greatly reduces the /sup 222/Rn emanation of uranium mill tailings. The structure of thermally stabilized tailings has been appreciably altered producing a material that will have minimal management requirements and will be applicable to on-site processing and disposal. The mineralogy of untreated tailings is presented to define the structure of the original materials. Quartz predominates in most tailings samples; however, appreciable quantities of gypsum, clay, illite, or albites are found in some tailings. Samples from the Durango and Shiprock sites have plagioclase-type aluminosilicates and non-aluminum silicates as major components. The iron-rich vanadium tailings from the Salt Lake City site contain appreciable quantities of ..cap alpha..-hematite and chloroapatite. The reduction in radon emanation power and changes in mineralogy as a function of sintering temperature (500 to 1200(NiAsS) are considered possible species for consideraed. The calculated activity data of the various carbonate, sulfate and hydroxide species in the Li/sup +/Na/sup +/K/sup +//CO/sub 3/ = SO/sub 4/ = OH/sup -/ system have been combined f liquidus surfaces, and estimated error limits are given for each system. A comng payback period, but as the initial cost of the SAHPS is reduced and fuel prices increase, the payback period of a SAHPS will be shorter and could be competitive with other conventional heating/cooling systems.

  12. Tail-biting: a new perspective.

    PubMed

    Taylor, Nina R; Main, David C J; Mendl, Mike; Edwards, Sandra A

    2010-11-01

    Tail-biting data from different studies are difficult to compare because a range of definitions of tail-biting behaviour and tail-biting lesions are used. Although records from abattoirs provide a large database, their usefulness is restricted as tail-biting is under-recorded and environmental and husbandry factors associated with the behaviour are unlikely to be known. Both farm and abattoir data provide no information on the number of pigs biting, only those bitten. Studying individual animals that tail-bite should give a better understanding of the pig's motivation to tail-bite and which of the components of its environment should be adjusted to improve welfare. This review examines the existing literature on tail-biting in pigs but considered from a new perspective using three different descriptive behavioural types, namely, 'two-stage', 'sudden-forceful' and 'obsessive', each of which may have different motivational bases. The article also considers the different environmental and husbandry factors which may affect each type of behaviour and discusses why this is such a complicated field and why it is often difficult to draw conclusions from available research. PMID:19804997

  13. Evaluation of major constraints to revegetation of lead/zinc mine tailings using bioassay techniques.

    PubMed

    Ye, Z H; Shu, W S; Zhang, Z Q; Lan, C Y; Wong, M H

    2002-06-01

    The residues from the extraction of lead/zinc (Pb/Zn) ores of most Pb/Zn mines are permanently stored in tailings ponds, which require revegetation to reduce their environmental impact. This can only be done if the main constraints on plant establishment are evaluated. This can readily be done by field and greenhouse studies. To test this, the properties of different tailings from Lechang Pb/Zn mine located at the north of Guangdong Province in southern China have been studied. Physical and chemical properties including concentrations of metals (Pb, Zn, Cd and Cu) in the tailings and soils collected from different sites have been measured. The results showed that tailings contain low nitrogen (0.016-0.075%), low-organic matter (0.58-1.78%), high salt (3.55-13.85 dS/m), and high total and diethylene-tetramine-pentaacetic acid (DTPA)-extractable metal concentrations (total: 1,019-1,642 microg g(-1) Pb, 3,078-6,773 microg g(-1) Zn, 8-23 microg g(-1) Cd, and 85-192 microg g(-1) Cu; DTPA-extractable: 59-178 microig g(-1) Pb, 21-200 microg g(-1) Zn, 0.30-1.5 mcirog g(-1) Cd, and 4.3-12 microg g(-1) Cu). Aqueous extracts of tailings/soils (10%, 20% and 30%, w/v) from different sites were prepared for testing their effects on seed germination and root elongation of a vegetable crop Brassica chinensis and a grass species Cynodon dactylon. It was found that root elongation provided a better evaluation of toxicity than seed germination. The ranking of toxicity using root elongation was: high-sulfur tailings > tailing dam > sparsely vegetated tailings > densely vegetated tailings > mountain soil for both plants. This order was consistent with DTPA-extractable Pb contents in the tailings and soils. B. chinensis seedlings were then grown in the mixtures of different proportions of tailings and farm soil for 4 weeks, and the results (dry weights of seedlings) were in line with the root elongation test. All these demonstrated that heavy metal toxicity, especially available Pb, low

  14. Engineering assessment of inactive uranium mill tailings

    SciTech Connect

    Not Available

    1981-07-01

    The Grand Junction site has been reevaluated in order to revise the October 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented herein range from millsite and off-site decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through VIII). Cost estimates for the eight options range from about $10,200,000 for stabilization in-place to about $39,500,000 for disposal in the DeBeque area, at a distance of about 35 mi, using transportation by rail. If transportation to DeBeque were by truck, the cost estimated to be about $41,900,000. Three principal alternatives for the reprocessing of the Grand Junction tailings were examined: (a) heap leaching; (b) treatment at an existing mill; and (c) reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be about $200/lb by heap leach and $150/lb by conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery appears not to be economically attractive.

  15. DNA methylation affected by male sterile cytoplasm in rice (Oryza sativa L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Male sterile cytoplasm plays an important role in hybrid rice and cytoplasmic effects are sufficiently documented. However, no reports are available on DNA methylation affected by male sterile cytoplasm in hybrid rice. We used a methylation sensitive amplified polymorphism (MSAP) technique to charac...

  16. Structural Characterization of the Crimean-Congo Hemorrhagic Fever Virus Gn Tail Provides Insight into Virus Assembly*

    PubMed Central

    Estrada, D. Fernando; De Guzman, Roberto N.

    2011-01-01

    The RNA virus that causes the Crimean Congo Hemorrhagic Fever (CCHF) is a tick-borne pathogen of the Nairovirus genus, family Bunyaviridae. Unlike many zoonotic viruses that are only passed between animals and humans, the CCHF virus can also be transmitted from human to human with an overall mortality rate approaching 30%. Currently, there are no atomic structures for any CCHF virus proteins or for any Nairovirus proteins. A critical component of the virus is the envelope Gn glycoprotein, which contains a C-terminal cytoplasmic tail. In other Bunyaviridae viruses, the Gn tail has been implicated in host-pathogen interaction and viral assembly. Here we report the NMR structure of the CCHF virus Gn cytoplasmic tail, residues 729–805. The structure contains a pair of tightly arranged dual ββα zinc fingers similar to those found in the Hantavirus genus, with which it shares about 12% sequence identity. Unlike Hantavirus zinc fingers, however, the CCHF virus zinc fingers bind viral RNA and contain contiguous clusters of conserved surface electrostatics. Our results provide insight into a likely role of the CCHF virus Gn zinc fingers in Nairovirus assembly. PMID:21507948

  17. Histopathological Characterization of Tail Injury and Traumatic Neuroma Development after Tail Docking in Piglets.

    PubMed

    Sandercock, D A; Smith, S H; Di Giminiani, P; Edwards, S A

    2016-07-01

    Tail docking of neonatal pigs is widely used as a measure to reduce the incidence of tail biting, a complex management problem in the pig industry. Concerns exist over the long-term consequences of tail docking for possible tail stump pain sensitivity due to the development of traumatic neuromas in injured peripheral nerves. Tail stumps were obtained post mortem from four female pigs at each of 1, 4, 8 and 16 weeks following tail amputation (approximately two-thirds removed) by a gas-heated docking iron on post natal day 3. Tissues were processed routinely for histopathological examination. Non-neural inflammatory and reparative epidermal and dermal changes associated with tissue thickening and healing were observed 1 to 4 months after docking. Mild neutrophilic inflammation was present in some cases, although this and other degenerative and non-neural reparative changes are not likely to have caused pain. Traumatic neuroma and neuromatous tissue development was not observed 1 week after tail docking, but was evident 1 month after tail docking. Over time there was marked nerve sheath and axonal proliferation leading to the formation of neuromata, which were either localized and circumscribed or comprised of multiple axons dispersed within granulation tissue. Four months after tail resection, neuroma formation was still incomplete, with possible implications for sensitivity of the tail stump. PMID:27302763

  18. Variation in Salamander Tail Regeneration Is Associated with Genetic Factors That Determine Tail Morphology

    PubMed Central

    Voss, Gareth J.; Kump, D. Kevin; Walker, John A.; Voss, S. Randal

    2013-01-01

    Very little is known about the factors that cause variation in regenerative potential within and between species. Here, we used a genetic approach to identify heritable genetic factors that explain variation in tail regenerative outgrowth. A hybrid ambystomatid salamander (Ambystoma mexicanum x A. andersoni) was crossed to an A. mexicanum and 217 offspring were induced to undergo metamorphosis and attain terrestrial adult morphology using thyroid hormone. Following metamorphosis, each salamander’s tail tip was amputated and allowed to regenerate, and then amputated a second time and allowed to regenerate. Also, DNA was isolated from all individuals and genotypes were determined for 187 molecular markers distributed throughout the genome. The area of tissue that regenerated after the first and second amputations was highly positively correlated across males and females. Males presented wider tails and regenerated more tail tissue during both episodes of regeneration. Approximately 66–68% of the variation in regenerative outgrowth was explained by tail width, while tail length and genetic sex did not explain a significant amount of variation. A small effect QTL was identified as having a sex-independent effect on tail regeneration, but this QTL was only identified for the first episode of regeneration. Several molecular markers significantly affected regenerative outgrowth during both episodes of regeneration, but the effect sizes were small (<4%) and correlated with tail width. The results show that ambysex and minor effect QTL explain variation in adult tail morphology and importantly, tail width. In turn, tail width at the amputation plane largely determines the rate of regenerative outgrowth. Because amputations in this study were made at approximately the same position of the tail, our results resolve an outstanding question in regenerative biology: regenerative outgrowth positively co-varies as a function of tail width at the amputation site. PMID:23843997

  19. Phosphagen kinase of the giant tubeworm Riftia pachyptila. Cloning and expression of cytoplasmic and mitochondrial isoforms of taurocyamine kinase.

    PubMed

    Uda, Kouji; Tanaka, Kumiko; Bailly, Xavier; Zal, Franck; Suzuki, Tomohiko

    2005-10-30

    The giant tubeworm Riftia pachyptila lives at deep-sea hydrothermal vents along the East Pacific Rise and the Galapagos Rift. The large size and high growth rate of R. pachyptila is supported by an endosymbiotic relationship with a chemosynthetic bacterium. Elucidation of the regulation of energy metabolism of the giant tubeworm remains an interesting problem. The purpose of this study is to determine the cDNA sequence of phosphagen kinase, one of the most important enzymes in energy metabolism, and to characterize its function. Two phosphagen kinase cDNA sequences amplified from the cDNA library of R. pachyptila showed high derived amino acid sequence identity (74%) with those of cytoplasmic taurocyamine kinase (TK) and mitochondrial TK from an annelid Arenicola brasiliensis. The cytoplasmic form of the Riftia recombinant enzyme showed stronger activity for the substrates taurocyamine and also considerable activity for lombricine (21% that of taurocyamine). The mitochondrial form, which was structurally similar to mitochondrial creatine kinase, showed stronger activity for taurocyamine, and a broader activity for various guanidine compounds: glycocyamine (35% that of taurocyamine), lombricine (31%) and arginine (3%). Both forms showed no activity for creatine. The difference in substrate specificities between the cytoplasmic and mitochondrial forms might be attributable to the large difference in the amino acid sequence of the GS region and/or several key amino acid residues for establishing guanidine substrate specificity. Based on these results, we conclude that Riftia contains at least two forms of TK as phosphagen kinase. We also report the kinetic parameters, Km and kcat, of Arenicola and Riftia TKs for the first time. The Km values for taurocyamine of Arenicola and Riftia TKs ranged from 0.9 to 4.0 mM and appear to be comparable to those of other annelid-specific enzymes, lombricine kinase and glycocyamine kinase, but are significantly lower than those of

  20. Double chromodomains cooperate to recognize the methylated histone H3 tail

    SciTech Connect

    Flanagan, John F.; Mi, Li-Zhi; Chruszcz, Maksymilian; Cymborowski, Marcin; Clines, Katrina L.; Kim, Youngchang; Minor, Wladek; Rastinejad, Fraydoon; Khorasanizadeh, Sepideh

    2010-07-19

    Chromodomains are modules implicated in the recognition of lysine-methylated histone tails and nucleic acids. CHD (for chromo-ATPase/helicase-DNA-binding) proteins regulate ATP-dependent nucleosome assembly and mobilization through their conserved double chromodomains and SWI2/SNF2 helicase/ATPase domain. The Drosophila CHD1 localizes to the interbands and puffs of the polytene chromosomes, which are classic sites of transcriptional activity. Other CHD isoforms (CHD3/4 or Mi-2) are important for nucleosome remodelling in histone deacetylase complexes. Deletion of chromodomains impairs nucleosome binding and remodelling by CHD proteins. Here we describe the structure of the tandem arrangement of the human CHD1 chromodomains, and its interactions with histone tails. Unlike HP1 and Polycomb proteins that use single chromodomains to bind to their respective methylated histone H3 tails, the two chromodomains of CHD1 cooperate to interact with one methylated H3 tail. We show that the human CHD1 double chromodomains target the lysine 4-methylated histone H3 tail (H3K4me), a hallmark of active chromatin. Methylammonium recognition involves two aromatic residues, not the three-residue aromatic cage used by chromodomains of HP1 and Polycomb proteins. Furthermore, unique inserts within chromodomain 1 of CHD1 block the expected site of H3 tail binding seen in HP1 and Polycomb, instead directing H3 binding to a groove at the inter-chromodomain junction.

  1. A Field and Modeling Study of Windblown Particles from a Uranium Mill Tailings Pile

    SciTech Connect

    Schwendiman, L. C.; Sehmel, G. A.; Horst, T. W.; Thomas, C. W.; Perkins, R. W.

    1980-06-01

    An extensive field study whose primary objective was to obtain knowledge and understanding of the nature and quantity of windblown particles from uranium mill tailings piles was conducted in the Ambrosia Lake District of New Mexico. The following major field tasks were undertaken: determination of physical, chemical, and radioactivity characteristics of mill tailings particles; an investigation of the nature and quantity of tailings particles in soil in the vicinity of tailings piles; and the determination of the nature and flux of particles being transported by wind as a function of wind speed and height. Results of the field study are presented. Particle size distributions and associated radioactivity were measured. Radioactivity relationships showed uranium daughters in mill tailings to be in essential radioactive equilibrium for the carbonate leach process but thorium-230 tends to be leached into the slurry water for the acid process mill tailings. One objective of the study was to relate windblown particle concentrations, fluxes, and particle sizes to wind speed. Hundreds of samples were taken and analyses were performed, but relationships between wind speed, airborne particle sizes and concentrations were found to be vague and inconclusive. A resuspension, deposition, and transport model was developed and applied using site meteorology. Ground deposition patterns predicted were similar to those found.

  2. Co-treatment of converter slag and pyrrhotite tailings via high pressure oxidative leaching.

    PubMed

    Perederiy, Ilya; Papangelakis, Vladimiros G; Buarzaiga, Mohamed; Mihaylov, Indje

    2011-10-30

    High pressure oxidative acid leaching (HPOXAL) was successfully applied to slow-cooled converter slags from Vale's operations in Sudbury (Ontario, Canada). Extractions of Ni, Co and Cu exceeded 90% within 15-20 min and levelled at 95-97% after 45 min at 250°C, 90 psi O(2) overpressure and 70 g/L initial H(2)SO(4). Pyrrhotite tailings with ∼ 0.6% Ni content were also tested as a source of sulphuric acid in high pressure oxidation. Co-leaching of pyrrhotite tailings with converter slags at the same temperature, oxygen partial pressure and equivalent stoichiometric H(2)SO(4) was found to have kinetics similar to that of leaching with sulphuric acid. Lowering the addition of pyrrhotite tailings (and hence, the acidity) was found to have a detrimental effect on the kinetics of leaching and final extractions (especially at 250°C), and cause precipitation of metal sulphates. Continuous on-line acidity measurements were facilitated in experiments with an electrodeless conductivity sensor. It was shown that acid plays a major role in the conversion of fayalite to hematite and silica, and the dissolution of the base metals, while oxygen overpressure (or dispersion efficiency) determines the rate of acid generation and re-generation. PMID:21893384

  3. Cytoplasmic and nuclear polyglutamine aggregates in SCA6 Purkinje cells.

    PubMed

    Ishikawa, K; Owada, K; Ishida, K; Fujigasaki, H; Shun Li, M; Tsunemi, T; Ohkoshi, N; Toru, S; Mizutani, T; Hayashi, M; Arai, N; Hasegawa, K; Kawanami, T; Kato, T; Makifuchi, T; Shoji, S; Tanabe, T; Mizusawa, H

    2001-06-26

    Aggregations of the alpha1A-calcium channel protein have been previously demonstrated in spinocerebellar ataxia type 6 (SCA6). Here the authors show that small aggregates, labeled by a monoclonal antibody 1C2 that preferentially detects expanded polyglutamine larger than that in SCA6 mutation, are present mainly in the cytoplasm but also in the nucleus of Purkinje cells. Although the length of expansion is small in SCA6, the current finding might indicate that SCA6 conforms to the pathogenic mechanism(s) in other polyglutamine diseases. PMID:11425948

  4. NUCLEAR DNA AND CYTOPLASMIC DNA FROM TISSUES OF HIGHER PLANTS

    PubMed Central

    Hotta, Yasuo; Bassel, Alix; Stern, Herbert

    1965-01-01

    Young wheat roots were labeled with 32P-inorganic phosphate. Following the labeling period, roots were homogenized in a sucrose medium and fractionated into nuclei, cytoplasmic particles (including proplastids and mitochondria), and a soluble fraction containing most of the microsomes. DNA prepared from the particles had a higher buoyant density than that from the nuclei and showed a marked loss in total label if the roots were exposed to non-radioactive medium for 48 hours prior to fractionation of the cells. PMID:5885425

  5. How do birds' tails work? Delta-wing theory fails to predict tail shape during flight.

    PubMed Central

    Evans, Matthew R; Rosén, Mikael; Park, Kirsty J; Hedenström, Anders

    2002-01-01

    Birds appear to use their tails during flight, but until recently the aerodynamic role that tails fulfil was largely unknown. In recent years delta-wing theory, devised to predict the aerodynamics of high-performance aircraft, has been applied to the tails of birds and has been successful in providing a model for the aerodynamics of a bird's tail. This theory now provides the conventional explanation for how birds' tails work. A delta-wing theory (slender-wing theory) has been used, as part of a variable-geometry model to predict how tail and wing shape should vary during flight at different airspeeds. We tested these predictions using barn swallows flying in a wind tunnel. We show that the predictions are not quantitatively well supported. This suggests that a new theory or a modified version of delta-wing theory is needed to adequately explain the way in which morphology varies during flight. PMID:12028763

  6. BIOMECHANICS. Why the seahorse tail is square.

    PubMed

    Porter, Michael M; Adriaens, Dominique; Hatton, Ross L; Meyers, Marc A; McKittrick, Joanna

    2015-07-01

    Whereas the predominant shapes of most animal tails are cylindrical, seahorse tails are square prisms. Seahorses use their tails as flexible grasping appendages, in spite of a rigid bony armor that fully encases their bodies. We explore the mechanics of two three-dimensional-printed models that mimic either the natural (square prism) or hypothetical (cylindrical) architecture of a seahorse tail to uncover whether or not the square geometry provides any functional advantages. Our results show that the square prism is more resilient when crushed and provides a mechanism for preserving articulatory organization upon extensive bending and twisting, as compared with its cylindrical counterpart. Thus, the square architecture is better than the circular one in the context of two integrated functions: grasping ability and crushing resistance. PMID:26138983

  7. Type 1 Tails: Solar Wind Interactions

    NASA Technical Reports Server (NTRS)

    Biermann, L.

    1972-01-01

    The ionization of the gas emitted by a comet is discussed along with the formation of a visible tail, and the bow shock front upstream toward the sun. Questions that a cometary probe can answer are listed.

  8. Tail mean and related robust solution concepts

    NASA Astrophysics Data System (ADS)

    Ogryczak, Włodzimierz

    2014-01-01

    Robust optimisation might be viewed as a multicriteria optimisation problem where objectives correspond to the scenarios although their probabilities are unknown or imprecise. The simplest robust solution concept represents a conservative approach focused on the worst-case scenario results optimisation. A softer concept allows one to optimise the tail mean thus combining performances under multiple worst scenarios. We show that while considering robust models allowing the probabilities to vary only within given intervals, the tail mean represents the robust solution for only upper bounded probabilities. For any arbitrary intervals of probabilities the corresponding robust solution may be expressed by the optimisation of appropriately combined mean and tail mean criteria thus remaining easily implementable with auxiliary linear inequalities. Moreover, we use the tail mean concept to develope linear programming implementable robust solution concepts related to risk averse optimisation criteria.

  9. The Distant Sodium Tail of Mercury

    NASA Technical Reports Server (NTRS)

    Potter, A. E.; Killen, R. M.; Morgan, T. H.

    2001-01-01

    Models of the sodium atmosphere of Mercury predict the possible existence of a cornet-like sodium tail. Detection and mapping of the predicted sodium tail would provide quantitative data on the energy of the process that produces sodium atoms from the planetary surface. Previous efforts to detect the sodium tail by means of observations done during daylight hours have been only partially successful because scattered sunlight obscured the weak sodium emissions in the tail. However, at greatest eastern elongation around the March equinox in the northern hemisphere, Mercury can be seen as an evening star in astronomical twilight. At this time, the intensity of scattered sunlight is low enough that sodium emissions as low as 500 Rayleighs can be detected. Additional information is contained in the original extended abstract.

  10. Horizontal tail loads in maneuvering flight

    NASA Technical Reports Server (NTRS)

    Pearson, Henry A; Mcgowan, William A; Donegan, James J

    1951-01-01

    A method is given for determining the horizontal tail loads in maneuvering flight. The method is based upon the assignment of a load-factor variation with time and the determination of a minimum time to reach peak load factor. The tail load is separated into various components. Examination of these components indicated that one of the components was so small that it could be neglected for most conventional airplanes; therefore, the number of aerodynamic parameters needed in this computation of tail loads was reduced to a minimum. In order to illustrate the method, as well as to show the effect of the main variables, a number of examples are given. Some discussion is given regarding the determination of maximum tail loads, maximum pitching accelerations, and maximum pitching velocities obtainable.

  11. Cytoplasm affects grain weight and filled-grain ratio in indica rice

    PubMed Central

    2011-01-01

    Background Cytoplasmic effects on agronomic traits -involving cytoplasmic and nuclear genomes of either different species or different cultivars - are well documented in wheat but have seldom been demonstrated in rice (Oryza sativa L.). To detect cytoplasmic effects, we introgressed the nuclear genomes of three indica cultivars - Guichao 2, Jiangchengkugu, and Dianrui 449 - into the cytoplasms of six indica cultivars - Dijiaowujian, Shenglixian, Zhuzhan, Nantehao, Aizizhan, and Peta. These 18 nuclear substitution lines were evaluated during the winter season of 2005 in Sanya, Hainan, China, and during the summer season of 2006 in Kunming, Yunnan, China. The effects of 6 cytoplasm sources, 3 nucleus sources, 2 locations and their interactions were estimated for plant height, panicle length, panicle number per plant, spikelet number per panicle, grain weight, filled-grain ratio, and yield per plot. Results For five of the seven traits, analysis of variance showed that there were no significant cytoplasmic effects or interactions involving cytoplasmic effects. The effect of cytoplasm on 1000-grain weight was highly significant. Mean 1000-grain weight over the two locations in four of the six cytoplasms clustered close to the overall mean, whereas plants with Nantehao cytoplasm had a high, and those with Peta cytoplasm a low mean grain weight. There was a highly significant three-way interaction affecting filled-grain ratio. At Sanya, cytoplasms varied in very narrow ranges within nuclear backgrounds. Strong cytoplasmic effects were observed only at Kunming and in only two of the three nuclear backgrounds; in the Jianchenkugu nuclear background, there was no evidence of strong cytoplasmic effects at either location. In the Dianrui 449 and Guichao 2 nuclear background evaluated at Kunming, filled-grain ratios of the six cytoplasms showed striking rank shifts Conclusions We detected cytoplasmic variation for two agronomically important traits in indica rice. The

  12. The cytosolic tail of the tumor marker protein Trop2 - a structural switch triggered by phosphorylation

    NASA Astrophysics Data System (ADS)

    Pavšič, Miha; Ilc, Gregor; Vidmar, Tilen; Plavec, Janez; Lenarčič, Brigita

    2015-05-01

    Trop2 is a transmembrane signaling glycoprotein upregulated in stem and carcinoma cells. Proliferation-enhancing signaling involves regulated intramembrane proteolytic release of a short cytoplasmic fragment, which is later engaged in a cytosolic signaling complex. We propose that Trop2 function is modulated by phosphorylation of a specific serine residue within this cytosolic region (Ser303), and by proximity effects exerted on the cytosolic tail by Trop2 dimerization. Structural characterization of both the transmembrane (Trop2TM) and cytosolic regions (Trop2IC) support this hypothesis, and shows that the central region of Trop2IC forms an α-helix. Comparison of NMR structures of non-phosphorylated and phosphorylated forms suggest that phosphorylation of Trop2IC triggers salt bridge reshuffling, resulting in significant conformational changes including ordering of the C-terminal tail. In addition, we demonstrate that the cytosolic regions of two Trop2 subunits can be brought into close proximity via transmembrane part dimerization. Finally, we show that Ser303-phosphorylation significantly affects the structure and accessibility of functionally important regions of the cytosolic tail. These observed structural features of Trop2 at the membrane-cytosol interface could be important for regulation of Trop2 signaling activity.

  13. In-situ study of beneficial utilization of coal fly ash in reactive mine tailings.

    PubMed

    Lee, Joon Kyu; Shang, Julie Q; Wang, Hongliu; Zhao, Cheng

    2014-03-15

    Oxidation of reactive mine tailings and subsequent generation of acid mine drainage (AMD) have been long recognized as the largest environmental concern for the mining industry. Laboratory studies on utilization of coal fly ash in management of reactive mine tailings have shown reducing water and oxygen infiltration into tailings matrix, thus preventing oxidation of sulphide minerals and acid generation. However, few data from field studies to evaluate the performance of co-placement of mine tailings and fly ash (CMF hereafter) are reported in the open literature. This paper documents the construction and instrumentation of three CMF systems on the Musselwhite mine located in Ontario, Canada and presents results of 3-year real time monitoring. The field data indicates that the CMFs reduced the ingress of water due to cementation generated by hydration of fly ash. It was also found that the electrical conductivity of leachate from CMFs decreased in the early stage of co-placement, compared to the control. With further study, the principle and approach demonstrated in this paper can be adopted as a sustainable technology in the mine tailings management. PMID:24525077

  14. Effects of tail docking and docking length on neuroanatomical changes in healed tail tips of pigs.

    PubMed

    Herskin, M S; Thodberg, K; Jensen, H E

    2015-04-01

    In pig production, piglets are tail docked at birth in order to prevent tail biting later in life. In order to examine the effects of tail docking and docking length on the formation of neuromas, we used 65 pigs and the following four treatments: intact tails (n=18); leaving 75% (n=17); leaving 50% (n=19); or leaving 25% (n=11) of the tail length on the pigs. The piglets were docked between day 2 and 4 after birth using a gas-heated apparatus, and were kept under conventional conditions until slaughter at 22 weeks of age, where tails were removed and examined macroscopically and histologically. The tail lengths and diameters differed at slaughter (lengths: 30.6±0.6; 24.9±0.4; 19.8±0.6; 8.7±0.6 cm; P<0.001; tail diameter: 0.5±0.03; 0.8±0.02; 1.0±0.03; 1.4±0.04 cm; P<0.001, respectively). Docking resulted in a higher proportion of tails with neuromas (64 v. 0%; P<0.001), number of neuromas per tail (1.0±0.2 v. 0; P<0.001) and size of neuromas (1023±592 v. 0 μm; P<0.001). The results show that tail docking piglets using hot-iron cautery causes formation of neuromas in the outermost part of the tail tip. The presence of neuromas might lead to altered nociceptive thresholds, which need to be confirmed in future studies. PMID:25482535

  15. TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782

    SciTech Connect

    Knierman, Karen A.; Scowen, Paul; Veach, Todd; Groppi, Christopher; Mullan, Brendan; Charlton, Jane; Konstantopoulos, Iraklis; Knezek, Patricia M. E-mail: paul.scowen@asu.edu E-mail: cgroppi@asu.edu E-mail: iraklis@aao.gov.au

    2013-09-10

    The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio {approx}4: 1 occurring {approx}200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun. However, deep UBVR and H{alpha} narrowband images show evidence of recent star formation in the western tail, though it lacks massive star clusters and cluster complexes. Using Herschel PACS spectroscopy, we discover 158 {mu}m [C II] emission at the location of the three most luminous H{alpha} sources in the eastern tail, but not at the location of the even brighter H{alpha} source in the western tail. The western tail is found to have a normal star formation efficiency (SFE), but the eastern tail has a low SFE. The lack of CO and [C II] emission suggests that the western tail H II region may have a low carbon abundance and be undergoing its first star formation. The western tail is more efficient at forming stars, but lacks massive clusters. We propose that the low SFE in the eastern tail may be due to its formation as a splash region where gas heating is important even though it has sufficient molecular and neutral gas to make massive star clusters. The western tail, which has lower gas surface density and does not form high-mass star clusters, is a tidally formed region where gravitational compression likely enhances star formation.

  16. Shake a Tail Feather: The Evolution of the Theropod Tail into a Stiff Aerodynamic Surface

    PubMed Central

    Pittman, Michael; Gatesy, Stephen M.; Upchurch, Paul; Goswami, Anjali; Hutchinson, John R.

    2013-01-01

    Theropod dinosaurs show striking morphological and functional tail variation; e.g., a long, robust, basal theropod tail used for counterbalance, or a short, modern avian tail used as an aerodynamic surface. We used a quantitative morphological and functional analysis to reconstruct intervertebral joint stiffness in the tail along the theropod lineage to extant birds. This provides new details of the tail’s morphological transformation, and for the first time quantitatively evaluates its biomechanical consequences. We observe that both dorsoventral and lateral joint stiffness decreased along the non-avian theropod lineage (between nodes Theropoda and Paraves). Our results show how the tail structure of non-avian theropods was mechanically appropriate for holding itself up against gravity and maintaining passive balance. However, as dorsoventral and lateral joint stiffness decreased, the tail may have become more effective for dynamically maintaining balance. This supports our hypothesis of a reduction of dorsoventral and lateral joint stiffness in shorter tails. Along the avian theropod lineage (Avialae to crown group birds), dorsoventral and lateral joint stiffness increased overall, which appears to contradict our null expectation. We infer that this departure in joint stiffness is specific to the tail’s aerodynamic role and the functional constraints imposed by it. Increased dorsoventral and lateral joint stiffness may have facilitated a gradually improved capacity to lift, depress, and swing the tail. The associated morphological changes should have resulted in a tail capable of producing larger muscular forces to utilise larger lift forces in flight. Improved joint mobility in neornithine birds potentially permitted an increase in the range of lift force vector orientations, which might have improved flight proficiency and manoeuvrability. The tail morphology of modern birds with tail fanning capabilities originated in early ornithuromorph birds. Hence

  17. Targeting of Transmembrane Protein Shrew-1 to Adherens Junctions Is Controlled by Cytoplasmic Sorting Motifs

    PubMed Central

    Jakob, Viktor; Schreiner, Alexander; Tikkanen, Ritva

    2006-01-01

    We recently identified transmembrane protein shrew-1 and showed that it is able to target to adherens junctions in polarized epithelial cells. This suggested shrew-1 possesses specific basolateral sorting motifs, which we analyzed by mutational analysis. Systematic mutation of amino acids in putative sorting signals in the cytoplasmic domain of shrew-1 revealed three tyrosines and a dileucine motif necessary for basolateral sorting. Substitution of these amino acids leads to apical localization of shrew-1. By applying tannic acid to either the apical or basolateral part of polarized epithelial cells, thereby blocking vesicle fusion with the plasma membrane, we obtained evidence that the apically localized mutants were primarily targeted to the basolateral membrane and were then redistributed to the apical domain. Further support for a postendocytic sorting mechanism of shrew-1 was obtained by demonstrating that μ1B, a subunit of the epithelial cell-specific adaptor complex AP-1B, interacts with shrew-1. In conclusion, our data provide evidence for a scenario where shrew-1 is primarily delivered to the basolateral membrane by a so far unknown mechanism. Once there, adaptor protein complex AP-1B is involved in retaining shrew-1 at the basolateral membrane by postendocytic sorting mechanisms. PMID:16707570

  18. The sodium tail of the Moon

    NASA Astrophysics Data System (ADS)

    Matta, M.; Smith, S.; Baumgardner, J.; Wilson, J.; Martinis, C.; Mendillo, M.

    2009-12-01

    During the few days centered about new Moon, the lunar surface is optically hidden from Earth-based observers. However, the Moon still offers an observable: an extended sodium tail. The lunar sodium tail is the escaping "hot" component of a coma-like exosphere of sodium generated by photon-stimulated desorption, solar wind sputtering and meteoroid impact. Neutral sodium atoms escaping lunar gravity experience solar radiation pressure that drives them into the anti-solar direction forming a comet-like tail. During new Moon time, the geometry of the Sun, Moon and Earth is such that the anti-sunward sodium flux is perturbed by the terrestrial gravitational field resulting in its focusing into a dense core that extends beyond the Earth. An all-sky camera situated at the El Leoncito Observatory (CASLEO) in Argentina has been successfully imaging this tail through a sodium filter at each lunation since April 2006. This paper reports on the results of the brightness of the lunar sodium tail spanning 31 lunations between April 2006 and September 2008. Brightness variability trends are compared with both sporadic and shower meteor activity, solar wind proton energy flux and solar near ultra violet (NUV) patterns for possible correlations. Results suggest minimal variability in the brightness of the observed lunar sodium tail, generally uncorrelated with any single source, yet consistent with a multi-year period of minimal solar activity and non-intense meteoric fluxes.

  19. The Sodium Tail of the Moon

    NASA Technical Reports Server (NTRS)

    Matta, M.; Smith, S.; Baumgardner, J.; Wilson, J.; Martinis, C.; Mendillo, M.

    2009-01-01

    During the few days centered about new Moon, the lunar surface is optically hidden from Earth-based observers. However, the Moon still offers an observable: an extended sodium tail. The lunar sodium tail is the escaping "hot" component of a coma-like exosphere of sodium generated by photon-stimulated desorption, solar wind sputtering and meteoroid impact. Neutral sodium atoms escaping lunar gravity experience solar radiation pressure that drives them into the anti-solar direction forming a comet-like tail. During new Moon time, the geometry of the Sun, Moon and Earth is such that the anti-sunward sodium flux is perturbed by the terrestrial gravitational field resulting in its focusing into a dense core that extends beyond the Earth. An all-sky camera situated at the El Leoncito Observatory (CASLEO) in Argentina has been successfully imaging this tail through a sodium filter at each lunation since April 2006. This paper reports on the results of the brightness of the lunar sodium tail spanning 31 lunations between April 2006 and September 2008. Brightness variability trends are compared with both sporadic and shower meteor activity, solar wind proton energy flux and solar near ultra violet (NUV) patterns for possible correlations. Results suggest minimal variability in the brightness of the observed lunar sodium tail, generally uncorrelated with any single source, yet consistent with a multi-year period of minimal solar activity and non-intense meteoric fluxes.

  20. Four tails problems for dynamical collapse theories

    NASA Astrophysics Data System (ADS)

    McQueen, Kelvin J.

    2015-02-01

    The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem dilemma) shows that solving the third by replacing the Gaussian with a non-Gaussian collapse function introduces new conflict with relativity theory.

  1. Binding of the cytoplasmic domain of CD28 to the plasma membrane inhibits Lck recruitment and signaling.

    PubMed

    Dobbins, Jessica; Gagnon, Etienne; Godec, Jernej; Pyrdol, Jason; Vignali, Dario A A; Sharpe, Arlene H; Wucherpfennig, Kai W

    2016-01-01

    The T cell costimulatory receptor CD28 is required for the full activation of naïve T cells and for the development and maintenance of Foxp3(+) regulatory T (Treg) cells. We showed that the cytoplasmic domain of CD28 was bound to the plasma membrane in resting cells and that ligand binding to CD28 resulted in its release. Membrane binding by the CD28 cytoplasmic domain required two clusters of basic amino acid residues, which interacted with the negatively charged inner leaflet of the plasma membrane. These same clusters of basic residues also served as interaction sites for Lck, a Src family kinase critical for CD28 function. This signaling complex was further stabilized by the Lck-mediated phosphorylation of CD28 Tyr(207) and the subsequent binding of the Src homology 2 (SH2) domain of Lck to this phosphorylated tyrosine. Mutation of the basic clusters in the CD28 cytoplasmic domain reduced the recruitment to the CD28-Lck complex of protein kinase Cθ (PKCθ), which serves as a key effector kinase in the CD28 signaling pathway. Consequently, mutation of either a basic cluster or Tyr(207) impaired CD28 function in mice as shown by the reduced thymic differentiation of FoxP3(+) Treg cells. On the basis of these results, we propose a previously undescribed model for the initiation of CD28 signaling. PMID:27460989

  2. Cytoplasmic STAT4 Promotes Antiviral Type I IFN Production by Blocking CHIP-Mediated Degradation of RIG-I.

    PubMed

    Zhao, Kai; Zhang, Qian; Li, Xia; Zhao, Dezhi; Liu, Yiqi; Shen, Qicong; Yang, Mingjin; Wang, Chunmei; Li, Nan; Cao, Xuetao

    2016-02-01

    Retinoic acid-inducible gene I (RIG-I) signaling is critical to host innate immune response against RNA virus infection. Numerous factors use different mechanisms to regulate RIG-I signaling. In this study, we report that STAT family member STAT4 promotes RIG-I-triggered type I IFN production in antiviral innate immunity. Silencing of STAT4 impaired IFN-β production in macrophages upon RNA virus infection, whereas overexpression of STAT4 enhanced RIG-I-induced IFN-β promoter activation and IFN-stimulated response element activity. Silencing of STAT4 increased degradation of RIG-I. Interestingly, during RNA virus infection STAT4 was found to be constantly present in cytoplasm of macrophages without Tyr(693) phosphorylation, which is required for its classical activation and nuclear translocation. Mechanistically, cytoplasmic STAT4 could interact with E3 ligase CHIP and block RIG-I and CHIP association, preventing CHIP-mediated proteasomal degradation of RIG-I via K48-linked ubiquitination. Our study provides a new manner for posttranslational regulation of RIG-I signaling and identifies a previously unknown function of cytoplasm-localized STAT4 in antiviral innate immunity. PMID:26695369

  3. Activities of the Cytoplasmic Domains of Patched-1 Modulate but Are Not Essential for the Regulation of Canonical Hedgehog Signaling.

    PubMed

    Fleet, Andrew; Lee, Jennifer P Y; Tamachi, Aaliya; Javeed, Imaan; Hamel, Paul A

    2016-08-19

    The Hedgehog (Hh) pathway is a highly conserved signaling cascade crucial for cell fate determination during embryogenesis. Response to the Hh ligands is mediated by the receptor Patched-1 (Ptch1), a 12-pass transmembrane glycoprotein. Despite its essential role in Hh signaling and its activity as a tumor suppressor, Ptch1 remains largely uncharacterized. We demonstrate here that Ptch1 binds to itself to form oligomeric structures. Oligomerization is mediated by two distinct, structurally disordered, intracellular domains spanning amino acids 584-734 ("middle loop") and 1162-1432 (C terminus). However, oligomerization is not required for Ptch1-dependent regulation of the canonical Hh pathway operating through Smo. Expression of a mutant protein that deletes both regions represses the Hh pathway and responds to the addition of Hh ligand independent of its inability to bind other factors such as Smurf2. Additionally, deletion of the cytoplasmic middle loop domain generates a Ptch1 mutant that, despite binding to Hh ligand, constitutively suppresses Hh signaling and increases the length of primary cilia. Constitutive activity because of deletion of this region is reversed by further deletion of specific sequences in the cytoplasmic C-terminal domain. These data reveal an interaction between the cytoplasmic domains of Ptch1 and that these domains modulate Ptch1 activity but are not essential for regulation of the Hh pathway. PMID:27325696

  4. Cytoplasmic translocation of the retinoblastoma protein disrupts sarcomeric organization.

    PubMed

    Araki, Keigo; Kawauchi, Keiko; Hirata, Hiroaki; Yamamoto, Mie; Taya, Yoichi

    2013-01-01

    Skeletal muscle degeneration is a complication arising from a variety of chronic diseases including advanced cancer. Pro-inflammatory cytokine TNF-α plays a pivotal role in mediating cancer-related skeletal muscle degeneration. Here, we show a novel function for retinoblastoma protein (Rb), where Rb causes sarcomeric disorganization. In human skeletal muscle myotubes (HSMMs), up-regulation of cyclin-dependent kinase 4 (CDK4) and concomitant phosphorylation of Rb was induced by TNF-α treatment, resulting in the translocation of phosphorylated Rb to the cytoplasm. Moreover, induced expression of the nuclear exporting signal (NES)-fused form of Rb caused disruption of sarcomeric organization. We identified mammalian diaphanous-related formin 1 (mDia1), a potent actin nucleation factor, as a binding partner of cytoplasmic Rb and found that mDia1 helps maintain the structural integrity of the sarcomere. These results reveal a novel non-nuclear function for Rb and suggest a potential mechanism of TNF-α-induced disruption of sarcomeric organization. DOI: http://dx.doi.org/10.7554/eLife.01228.001. PMID:24302570

  5. Cytoplasmic protein methylation is essential for neural crest migration

    PubMed Central

    Vermillion, Katie L.; Lidberg, Kevin A.

    2014-01-01

    As they initiate migration in vertebrate embryos, neural crest cells are enriched for methylation cycle enzymes, including S-adenosylhomocysteine hydrolase (SAHH), the only known enzyme to hydrolyze the feedback inhibitor of trans-methylation reactions. The importance of methylation in neural crest migration is unknown. Here, we show that SAHH is required for emigration of polarized neural crest cells, indicating that methylation is essential for neural crest migration. Although nuclear histone methylation regulates neural crest gene expression, SAHH and lysine-methylated proteins are abundant in the cytoplasm of migratory neural crest cells. Proteomic profiling of cytoplasmic, lysine-methylated proteins from migratory neural crest cells identified 182 proteins, several of which are cytoskeleton related. A methylation-resistant form of one of these proteins, the actin-binding protein elongation factor 1 alpha 1 (EF1α1), blocks neural crest migration. Altogether, these data reveal a novel and essential role for post-translational nonhistone protein methylation during neural crest migration and define a previously unknown requirement for EF1α1 methylation in migration. PMID:24379414

  6. Ulcerative colitis and antineutrophil cytoplasmic antibodies in Hong Kong Chinese.

    PubMed

    Sung, J Y; Chan, K L; Hsu, R; Liew, C T; Lawton, J W

    1993-06-01

    Inflammatory bowel diseases are known to be rare among the Chinese. The diagnosis of ulcerative colitis has been difficult in some of the Asian countries where infective colitis is more prevalent. Twenty-three Hong Kong Chinese patients diagnosed to have ulcerative colitis were reviewed. The symptoms were relatively mild and extraintestinal manifestation had been rare. Patients responded well to steroid therapy and sulfasalazine. Three patients in this series were found to have cyst and/or trophozoites of Entamoeba histolytica in stool. In this series, 19 patients were tested for antineutrophil cytoplasmic antibody (ANCA). Fourteen patients (73.5%) were positive, of which six (31.5%) showed a perinuclear staining pattern and eight (42%) demonstrated a cytoplasmic pattern. Five patients (26.5%) were negative for any ANCA, and none was positive for both. Sera of these patients were also tested for anti-alpha granules, anti-myeloperoxidase, and anti-lactoferrin activities. None was positive. Control sera collected from 16 patients with irritable bowel syndrome were all negative for the tests. In conclusion, testing of ANCAs may help in making the diagnosis of idiopathic inflammatory bowel disease in difficult situations. PMID:8503382

  7. Cytoplasmic Dynein Antagonists with Improved Potency and Isoform Selectivity

    PubMed Central

    2015-01-01

    Cytoplasmic dyneins 1 and 2 are related members of the AAA+ superfamily (ATPases associated with diverse cellular activities) that function as the predominant minus-end-directed microtubule motors in eukaryotic cells. Dynein 1 controls mitotic spindle assembly, organelle movement, axonal transport, and other cytosolic, microtubule-guided processes, whereas dynein 2 mediates retrograde trafficking within motile and primary cilia. Small-molecule inhibitors are important tools for investigating motor protein-dependent mechanisms, and ciliobrevins were recently discovered as the first dynein-specific chemical antagonists. Here, we demonstrate that ciliobrevins directly target the heavy chains of both dynein isoforms and explore the structure–activity landscape of these inhibitors in vitro and in cells. In addition to identifying chemical motifs that are essential for dynein blockade, we have discovered analogs with increased potency and dynein 2 selectivity. These antagonists effectively disrupt Hedgehog signaling, intraflagellar transport, and ciliogenesis, making them useful probes of these and other cytoplasmic dynein 2-dependent cellular processes. PMID:26555042

  8. A cytoplasmic peptidoglycan amidase homologue controls mycobacterial cell wall synthesis

    PubMed Central

    Boutte, Cara C; Baer, Christina E; Papavinasasundaram, Kadamba; Liu, Weiru; Chase, Michael R; Meniche, Xavier; Fortune, Sarah M; Sassetti, Christopher M; Ioerger, Thomas R; Rubin, Eric J

    2016-01-01

    Regulation of cell wall assembly is essential for bacterial survival and contributes to pathogenesis and antibiotic tolerance in Mycobacterium tuberculosis (Mtb). However, little is known about how the cell wall is regulated in stress. We found that CwlM, a protein homologous to peptidoglycan amidases, coordinates peptidoglycan synthesis with nutrient availability. Surprisingly, CwlM is sequestered from peptidoglycan (PG) by localization in the cytoplasm, and its enzymatic function is not essential. Rather, CwlM is phosphorylated and associates with MurA, the first enzyme in PG precursor synthesis. Phosphorylated CwlM activates MurA ~30 fold. CwlM is dephosphorylated in starvation, resulting in lower MurA activity, decreased cell wall metabolism, and increased tolerance to multiple antibiotics. A phylogenetic analysis of cwlM implies that localization in the cytoplasm drove the evolution of this factor. We describe a system that controls cell wall metabolism in response to starvation, and show that this regulation contributes to antibiotic tolerance. DOI: http://dx.doi.org/10.7554/eLife.14590.001 PMID:27304077

  9. Human cytoplasmic actin proteins are encoded by a multigene family

    SciTech Connect

    Engel, J.; Gunning, P.; Kedes, L.

    1982-06-01

    The authors characterized nine human actin genes that they isolated from a library of cloned human DNA. Measurements of the thermal stability of hybrids formed between each cloned actin gene and ..cap alpha..-, ..beta..-, and ..gamma..-actin mRNA demonstrated that only one of the clones is most homologous to sarcomeric actin mRNA, whereas the remaining eight clones are most homologous to cytoplasmic actin mRNA. By the following criteria they show that these nine clones represent nine different actin gene loci rather than different alleles or different parts of a single gene: (i) the restriction enzyme maps of the coding regions are dissimilar; (ii) each clone contains sufficient coding region to encode all or most of an entire actin gene; and (iii) each clone contains sequences homologous to both the 5' and 3' ends of the coding region of a cloned chicken ..beta..-actin cDNA. They conclude, therefore, that the human cytoplasmic actin proteins are encoded by a multigene family.