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Sample records for anomalous type iv

  1. An Anomalous Type IV Secretion System in Rickettsia Is Evolutionarily Conserved

    PubMed Central

    Gillespie, Joseph J.; Ammerman, Nicole C.; Dreher-Lesnick, Sheila M.; Rahman, M. Sayeedur; Worley, Micah J.; Setubal, Joao C.; Sobral, Bruno S.; Azad, Abdu F.

    2009-01-01

    Background Bacterial type IV secretion systems (T4SSs) comprise a diverse transporter family functioning in conjugation, competence, and effector molecule (DNA and/or protein) translocation. Thirteen genome sequences from Rickettsia, obligate intracellular symbionts/pathogens of a wide range of eukaryotes, have revealed a reduced T4SS relative to the Agrobacterium tumefaciens archetype (vir). However, the Rickettsia T4SS has not been functionally characterized for its role in symbiosis/virulence, and none of its substrates are known. Results Superimposition of T4SS structural/functional information over previously identified Rickettsia components implicate a functional Rickettsia T4SS. virB4, virB8 and virB9 are duplicated, yet only one copy of each has the conserved features of similar genes in other T4SSs. An extraordinarily duplicated VirB6 gene encodes five hydrophobic proteins conserved only in a short region known to be involved in DNA transfer in A. tumefaciens. virB1, virB2 and virB7 are newly identified, revealing a Rickettsia T4SS lacking only virB5 relative to the vir archetype. Phylogeny estimation suggests vertical inheritance of all components, despite gene rearrangements into an archipelago of five islets. Similarities of Rickettsia VirB7/VirB9 to ComB7/ComB9 proteins of ε-proteobacteria, as well as phylogenetic affinities to the Legionella lvh T4SS, imply the Rickettsiales ancestor acquired a vir-like locus from distantly related bacteria, perhaps while residing in a protozoan host. Modern modifications of these systems likely reflect diversification with various eukaryotic host cells. Conclusion We present the rvh (Rickettsiales vir homolog) T4SS, an evolutionary conserved transporter with an unknown role in rickettsial biology. This work lays the foundation for future laboratory characterization of this system, and also identifies the Legionella lvh T4SS as a suitable genetic model. PMID:19279686

  2. Anomalous C IV and Si IV resonance lines in 36 Lyncis

    SciTech Connect

    Sadakane, K.

    1984-03-01

    Of the anomalously strong C IV and Si IV resonance lines found in the UV spectrum of the chemically peculiar star 36 Lyncis, the C IV lines near 1550 A are noted to be absent in about 40 other middle or late B-type main sequence stars. Also found is a peculiar intensity ratio between C IV and Si IV lines, where the former are stronger. The continuous energy distribution of 36 Lyn in the UV region fits with those of late B-type stars, and the presence of a hot, chromospheric or coronal gas is suggested. 14 references.

  3. Interplanetary Type IV Bursts

    NASA Astrophysics Data System (ADS)

    Hillaris, A.; Bouratzis, C.; Nindos, A.

    2016-08-01

    We study the characteristics of moving type IV radio bursts that extend to hectometric wavelengths (interplanetary type IV or type {IV}_{{IP}} bursts) and their relationship with energetic phenomena on the Sun. Our dataset comprises 48 interplanetary type IV bursts observed with the Radio and Plasma Wave Investigation (WAVES) instrument onboard Wind in the 13.825 MHz - 20 kHz frequency range. The dynamic spectra of the Radio Solar Telescope Network (RSTN), the Nançay Decametric Array (DAM), the Appareil de Routine pour le Traitement et l' Enregistrement Magnetique de l' Information Spectral (ARTEMIS-IV), the Culgoora, Hiraso, and the Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN) Radio Spectrographs were used to track the evolution of the events in the low corona. These were supplemented with soft X-ray (SXR) flux-measurements from the Geostationary Operational Environmental Satellite (GOES) and coronal mass ejections (CME) data from the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). Positional information of the coronal bursts was obtained by the Nançay Radioheliograph (NRH). We examined the relationship of the type IV events with coronal radio bursts, CMEs, and SXR flares. The majority of the events (45) were characterized as compact, their duration was on average 106 minutes. This type of events was, mostly, associated with M- and X-class flares (40 out of 45) and fast CMEs, 32 of these events had CMEs faster than 1000 km s^{-1}. Furthermore, in 43 compact events the CME was possibly subjected to reduced aerodynamic drag as it was propagating in the wake of a previous CME. A minority (three) of long-lived type {IV}_{{IP}} bursts was detected, with durations from 960 minutes to 115 hours. These events are referred to as extended or long duration and appear to replenish their energetic electron content, possibly from electrons escaping from the corresponding coronal

  4. Mucolipidosis Type IV: an Update

    PubMed Central

    Wakabayashi, Kazuyo; Gustafson, Ann Marie; Sidransky, Ellen; Goldin, Ehud

    2011-01-01

    Mucolipidosis type IV (MLIV) is a neurodevelopmental as well as neurodegenerative disorder with severe psychomotor developmental delay, progressive visual impairment, and achlorydria. It is characterized by the presence of lysosomal inclusions in many cell types in patients. MLIV is an autosomal recessive disease caused by mutations in MCOLN1, which encodes for mucolipin-1, a member of the transient receptor potential (TRP) cation channel family. Although approximately 70-80% of patients identified are Ashkenazi Jewish, MLIV is a pan-ethnic disorder. Importantly, while MLIV is thought to be a rare disease, its frequency may be greater than currently appreciated, for its common presentation as a cerebral palsy-like encephalopathy can lead to misdiagnosis. Moreover, patients with milder variants are often not recognized as having MLIV. This review provides an update on the ethnic distribution, clinical manifestations, laboratory findings, methods of diagnosis, molecular genetics, differential diagnosis, and treatment of patients with MLIV. An enhanced awareness of the manifestations of this disorder may help to elucidate the true frequency and range of symptoms associated with MLIV, providing insight into the pathogenesis of this multi-system disease. PMID:21763169

  5. Fe II fluorescence and anomalous C IV doublet intensities in symbiotic novae

    NASA Technical Reports Server (NTRS)

    Michalitsianos, A. G.; Kafatos, M.; Meier, S. R.

    1992-01-01

    The variation of absolute intensities of Bowen-excited Fe II emission in the symbiotic stars RR Tel, RX Pup, and AG Peg is examined. The C IV doublet intensity ratios in RR Tel were not anomalous between 1979 and 1989, and the ratio had typical values within the optically thin range. The intensity of individual Fe II Bowen-excited lines is correlated with the C IV 1548.2 A flux, suggesting the presence of a foreground Fe II region in which fluorescent-excited material responds to flux variations of C IV 1548.2 A. In RX Pup the combined fluxes of Fe II Bowen-pumped lines can account for an appreciable fraction of the flux deficit in the C IV 1548.2 A line when the C IV doublet ratio is less than the optically thick limit of unity. The Fe II Bowen lines in RX Pup exhibit a velocity range from 0 to 80 km/s, where several strong Fe II emission lines correspond to deep absorption structure in the C IV 1548.2 A line profile. In AG Peg and C IV 1548.2 A flux deficit cannot be explained by Fe II fluorescent absorption alone when the C IV doublet ratio anomaly is at an extreme.

  6. Compositions of Normal and Anomalous Eucrite-Type Mafic Achondrites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Peng, Z. X.; Mertzman, S. A.

    2016-01-01

    The most common asteroidal igneous meteorites are eucrite-type mafic achondrites - basalts and gabbros composed of ferroan pigeonite, ferroan augite, calcic plagioclase, silica, ilmenite, troilite, Ca-phosphate, chromite and Fe-metal. These rocks are thought to have formed on a single asteroid along with howardites and diogenites. However, high precision O-isotopic analyses have shown that some mafic achondrites have small, well-resolved, non-mass-dependent differences that have been interpreted as indicating derivation from different asteroids. Some of these O-anomalous mafic achondrites also have anomalous petrologic characteristics, strengthening the case that they hail from distinct parent asteroids. We present the results of bulk compositional studies of a suite of normal and anomalous eucrite-type basalts and cumulate gabbros.

  7. [Type IV of hypersensitivity and its subtypes].

    PubMed

    Czarnobilska, Ewa; Obtułowicz, Krystyna; Wsołek, Katarzyna

    2007-01-01

    Type IV of hypersensitivity reaction is usually manifested in the skin in different clinical pattern. According to traditional Gell and Coombs classification, the mechanism of IV type of allergic reaction has been associated with contact allergy with the activity of lymphocytes Th1 secreting interferon gamma. Now, this vision seems to be too simplified. In the last years there were publications, which can throw a new light on these complicated mechanisms leading to the development of the type IV of allergy, especially to drugs, nickel and other haptens and also can explain the differentiation of clinical pattern in respective patients. The skin symptoms in type IV of hypersensitivity are triggered by activation of specific T-cell CD4+ and CD8+. Immunohistochemical and functional analysis of reactive T-cell has shown that the delayed hypersensitivity reaction depends on the secreted cytokines. For example maculo-papular exanthema may be either triggered by Th1 or Th2 in nature and cytokines interferon gamma, tumor necrosis factor alfa or interleukin-4, 5 and 13. Bullous reactions (i.e. Stevens-Johnsons Syndrome or toxic epidermal necrolysis) are characterized by widespread keratinocyte apoptosis, a consequence of high CD8+ T-cell involvement and the molecular cytotoxicity of Fas, perforin and granzyme B. Pustular exanthema reactions are stimulated via the T-cell release of 11-8 and granulocyte-monocyte colony-stimulatig factor (GM-CSF). For the better understanding of these inflammatory cascades deleted type IV of hypersensitivity reactions have been re-classified into four main subtypes: 1. IVa with Th1 and monocyte directed and cytokines: IFNgamma, IL-1, IL-2, 2. IVb with Th2 and eosinophils directed and cytokines: L-5, IL-4, IL-13, 3. IVc with T CD8+ directed and cytokines: perforin, granzyme B, Fas Ligand, 4. IVd with T CD4+, CD8+ and neutrophil directed and cytokines: IL8, GM-CSF. Clinically delayed hypersensitivity eruptions are often an overlap of cytokine

  8. Type IV Pilin Proteins: Versatile Molecular Modules

    PubMed Central

    Giltner, Carmen L.; Nguyen, Ylan

    2012-01-01

    Summary: Type IV pili (T4P) are multifunctional protein fibers produced on the surfaces of a wide variety of bacteria and archaea. The major subunit of T4P is the type IV pilin, and structurally related proteins are found as components of the type II secretion (T2S) system, where they are called pseudopilins; of DNA uptake/competence systems in both Gram-negative and Gram-positive species; and of flagella, pili, and sugar-binding systems in the archaea. This broad distribution of a single protein family implies both a common evolutionary origin and a highly adaptable functional plan. The type IV pilin is a remarkably versatile architectural module that has been adopted widely for a variety of functions, including motility, attachment to chemically diverse surfaces, electrical conductance, acquisition of DNA, and secretion of a broad range of structurally distinct protein substrates. In this review, we consider recent advances in this research area, from structural revelations to insights into diversity, posttranslational modifications, regulation, and function. PMID:23204365

  9. Ratchet model for type IV pilus retraction

    NASA Astrophysics Data System (ADS)

    Lindén, Martin; Tuohimaa, Tomi; Jonsson, Ann-Beth; Wallin, Mats

    2004-03-01

    Type IV pilus rectraction is required for twitching motility in a wide range of bacteriae, including Neisseria gonorrhoeae, Myxococcus xanthus and Pseudomonas aeruginosa. The mechanism of retraction is believed to be filament disassembly mediated by PilT, a member of the AAA family of motor proteins. Recent laser tweezer measurements of the force-velocity relation of PilT in N. gonorrhoeae, reveal that single PilT complexes generate forces of over 100 pN. We assume that PilT forms a cyclic ATPase surrounding the base of the pilus and formulate a model of retraction in terms of coupled flashing ratchets. We obtain a force-velocity relation by numerical simulation of the model which is in qualitative agreement with the experimental results.

  10. Isolation of Bacterial Type IV Machine Subassemblies

    PubMed Central

    Sarkar, Mayukh K.; Husnain, Seyyed I.; Jakubowski, Simon J.; Christie, Peter J.

    2012-01-01

    The bacterial type IV secretion systems (T4SSs) deliver DNA and protein substrates to bacterial and eukaryotic target cells generally by a mechanism requiring direct contact between donor and target cells. Recent advances in defining the architectures of T4SSs have been made through isolation of machine sub-assemblies for further biochemical and ultrastructural analysis. Here, we describe a protocol for isolation and characterization of VirB protein complexes from the paradigmatic VirB/VirD4 T4SS of Agrobacterium tumefaciens. This protocol can be adapted for isolation of T4SS subassemblies from other gram-negative bacteria as well as gram-positive bacteria. The biological importance of isolated T4SS subcomplexes can be assessed by assaying for copurification of trapped or cross-linked substrates. This can be achieved with a modified form of the chromatin immunoprecipitation (ChIP) assay termed transfer DNA immunoprecipitation (TrIP). Here, a TrIP protocol is described for recovery of formaldehyde-cross-linked DNA substrate–channel subunit complexes from cells employing T4SSs for conjugative DNA transfer. PMID:23299736

  11. Structure of a Type IV Secretion System

    PubMed Central

    Rivera-Calzada, Angel; Braun, Nathalie; Connery, Sarah; Dujeancourt, Annick; Lu, Fang; Redzej, Adam; Fronzes, Rémi; Orlova, Elena V.; Waksman, Gabriel

    2014-01-01

    Bacterial type IV secretion (T4S) systems translocate virulence factors into eukaryotic cells1,2, distribute genetic material between bacteria, and have shown potential as a tool for the genetic modification of human cells3. Given the complex choreography of the substrate through the secretion apparatus4, the molecular mechanism of the T4S system has proven difficult to dissect in the absence of structural data for the entire machinery. Here we use electron microscopy (EM) to reconstruct the T4S system encoded by the Escherichia coli R388 conjugative plasmid. We show that eight proteins assemble in an intricate stoichiometric relationship to form a ~3 megadalton (MDa) nanomachine that spans the entire cell envelope. The structure comprises an outer membrane-associated core complex1 connected by a central stalk to a substantial inner membrane complex that is dominated by a battery of twelve VirB4 ATPase subunits organised as side by side hexameric barrels. Our results show a secretion system with markedly different architecture, and consequently mechanism, to other known bacterial secretion systems1,4-6. PMID:24670658

  12. Genetics Home Reference: mucopolysaccharidosis type IV

    MedlinePlus

    ... enzymes, GAGs accumulate within cells, specifically inside the lysosomes . Lysosomes are compartments in the cell that break down ... that cause molecules to build up inside the lysosomes are called lysosomal storage disorders. In MPS IV, ...

  13. Control of melanoma cell invasion by type IV collagen.

    PubMed

    Pasco, Sylvie; Brassart, Bertrand; Ramont, Laurent; Maquart, François-Xavier; Monboisse, Jean-Claude

    2005-01-01

    Malignant melanoma is the leading cause of death from diseases of the skin. This review summarizes the data from the literature and our laboratory addressing the effects of type IV collagen on melanoma progression. Many different sequences from type IV collagen promote melanoma cell adhesion, migration and invasion. The triple helical conformation of the collagenous domain plays a critical role in some of these interactions. However, recent studies from our group demonstrated that a sequence from the alpha3(IV) NC1 domain inhibits melanoma cell proliferation, migration and invasion by decreasing MMP production and activation. Peptide sequences from the alpha1(IV), alpha2(IV) and alpha3(IV) chains named arresten, canstatin and tumstatin, respectively were shown to inhibit angiogenesis. Further investigations regarding the inhibitory effects of the alpha(IV) NC1 domains will have a paramount relevance for the design of efficient strategies to limit melanoma development. PMID:15936594

  14. Non-helical type IV collagen polypeptides in human placenta.

    PubMed

    Kajimura, Daisuke; Takahashi, Seiichiro; Yoshikawa, Kiwamu; Hattori, Shunji; Sado, Yoshikazu; Imamura, Yasutada; Hayashi, Toshihiko

    2004-01-30

    Our previous reports showed that cultured human cells secrete non-disulfide-bonded non-helical alpha1(IV) and alpha2(IV) chains under physiological conditions. In the present report we show that the alpha(IV) chains in non-helical form were reactive to lectin ABA (Agaricus bisporus agglutinin), whereas the alpha(IV) chains secreted in triple-helical form were not. These results indicate that ABA could be used to distinguish the two conformational isomers of type IV collagen polypeptides. An alpha1(IV) chain isolated from human placenta with an antibody-coupled column showed a positive reaction to ABA, indicating that gelatin form of the type IV collagen alpha1(IV) chain is produced and retained in the tissue in vivo. A possible significance of the gelatin form is discussed from the finding that the non-helical alpha1(IV) chain purified with EDTA-free buffer contained degraded polypeptides including NC1-size domain and showed an apparent inhibition against activated pro-MMP-9. This is the first report to show that a gelatin form of protein exists in vivo. PMID:14715239

  15. Cellular Origins of Type IV Collagen Networks in Developing Glomeruli

    PubMed Central

    Abrahamson, Dale R.; Hudson, Billy G.; Stroganova, Larysa; Borza, Dorin-Bogdan; St. John, Patricia L.

    2009-01-01

    Laminin and type IV collagen composition of the glomerular basement membrane changes during glomerular development and maturation. Although it is known that both glomerular endothelial cells and podocytes produce different laminin isoforms at the appropriate stages of development, the cellular origins for the different type IV collagen heterotrimers that appear during development are unknown. Here, immunoelectron microscopy demonstrated that endothelial cells, mesangial cells, and podocytes of immature glomeruli synthesize collagen α1α2α1(IV). However, intracellular labeling revealed that podocytes, but not endothelial or mesangial cells, contain collagen α3α4α5(IV). To evaluate the origins of collagen IV further, we transplanted embryonic kidneys from Col4a3-null mutants (Alport mice) into kidneys of newborn, wildtype mice. Hybrid glomeruli within grafts containing numerous host-derived, wildtype endothelial cells never expressed collagen α3α4α5(IV). Finally, confocal microscopy of glomeruli from infant Alport mice that had been dually labeled with anti-collagen α5(IV) and the podocyte marker anti-GLEPP1 showed immunolabeling exclusively within podocytes. Together, these results indicate that collagen α3α4α5(IV) originates solely from podocytes; therefore, glomerular Alport disease is a genetic defect that manifests specifically within this cell type. PMID:19423686

  16. Cellular origins of type IV collagen networks in developing glomeruli.

    PubMed

    Abrahamson, Dale R; Hudson, Billy G; Stroganova, Larysa; Borza, Dorin-Bogdan; St John, Patricia L

    2009-07-01

    Laminin and type IV collagen composition of the glomerular basement membrane changes during glomerular development and maturation. Although it is known that both glomerular endothelial cells and podocytes produce different laminin isoforms at the appropriate stages of development, the cellular origins for the different type IV collagen heterotrimers that appear during development are unknown. Here, immunoelectron microscopy demonstrated that endothelial cells, mesangial cells, and podocytes of immature glomeruli synthesize collagen alpha 1 alpha 2 alpha1(IV). However, intracellular labeling revealed that podocytes, but not endothelial or mesangial cells, contain collagen alpha 3 alpha 4 alpha 5(IV). To evaluate the origins of collagen IV further, we transplanted embryonic kidneys from Col4a3-null mutants (Alport mice) into kidneys of newborn, wildtype mice. Hybrid glomeruli within grafts containing numerous host-derived, wildtype endothelial cells never expressed collagen alpha 3 alpha 4 alpha 5(IV). Finally, confocal microscopy of glomeruli from infant Alport mice that had been dually labeled with anti-collagen alpha 5(IV) and the podocyte marker anti-GLEPP1 showed immunolabeling exclusively within podocytes. Together, these results indicate that collagen alpha 3 alpha 4 alpha 5(IV) originates solely from podocytes; therefore, glomerular Alport disease is a genetic defect that manifests specifically within this cell type. PMID:19423686

  17. Type IV pili mechanochemically regulate virulence factors in Pseudomonas aeruginosa

    PubMed Central

    Persat, Alexandre; Inclan, Yuki F.; Engel, Joanne N.; Stone, Howard A.; Gitai, Zemer

    2015-01-01

    Bacteria have evolved a wide range of sensing systems to appropriately respond to environmental signals. Here we demonstrate that the opportunistic pathogen Pseudomonas aeruginosa detects contact with surfaces on short timescales using the mechanical activity of its type IV pili, a major surface adhesin. This signal transduction mechanism requires attachment of type IV pili to a solid surface, followed by pilus retraction and signal transduction through the Chp chemosensory system, a chemotaxis-like sensory system that regulates cAMP production and transcription of hundreds of genes, including key virulence factors. Like other chemotaxis pathways, pili-mediated surface sensing results in a transient response amplified by a positive feedback that increases type IV pili activity, thereby promoting long-term surface attachment that can stimulate additional virulence and biofilm-inducing pathways. The methyl-accepting chemotaxis protein-like chemosensor PilJ directly interacts with the major pilin subunit PilA. Our results thus support a mechanochemical model where a chemosensory system measures the mechanically induced conformational changes in stretched type IV pili. These findings demonstrate that P. aeruginosa not only uses type IV pili for surface-specific twitching motility, but also as a sensor regulating surface-induced gene expression and pathogenicity. PMID:26041805

  18. [Mucolipidoses type IV in a patient with mapuche ancestry].

    PubMed

    Hernández Ch, Marta; Méndez C, José Ignacio; Concha G, María José; Huete L, Isidro; González B, Sergio; Durán S, Gloria P

    2008-07-01

    We report a 7 year-old girl with mapuche ancestors, diagnosed as a cerebral palsy since infancy and on active rehabilitation. She acquired motor and cognitive skills at 3 years of age. At 5 years of age, a slow neurological deterioration started, associated to visual impairment. Optic atrophy was added to the typical neurological exam of ataxic cerebral palsy and the diagnosis was re-considered. Neuroimaging showed a slow and progressive atrophy of intracerebral structures and ultramicroscopy revealed intracytoplasmatic inclusions in conjunctiva and skin, compatible with mucolipidoses type IV (ML-IV). ML-IV must be included in the differential diagnosis of cerebral palsy associated with loss of acquired skills and progressive visual impairment. Electron microscopy of skin or conjunctiva is a useful diagnostic test. Suspicion of ML-IV must not be restricted to Ashkenazi Jewish population. PMID:18949166

  19. Ehlers-Danlos Syndrome Type IV with Bilateral Pneumothorax.

    PubMed

    Nakagawa, Hiroaki; Wada, Hiroshi; Hajiro, Takashi; Nagao, Taishi; Ogawa, Emiko; Hatamochi, Atsushi; Tanaka, Toshihiro; Nakano, Yasutaka

    2015-01-01

    A 17-year-old teen was hospitalized with bilateral pneumothorax. After the bilateral lungs were expanded using catheter tubes, he fully recovered and he was discharged from our hospital. He had a history of colon perforation. Ehlers-Danlos syndrome (EDS) was suspected due to the combination of colon perforation and pneumothorax, and EDS type IV was confirmed after a genetic study identified a c.1511g>a mutation in the COL3A1 gene. This is the first report of bilateral pneumothorax caused by EDS type IV. Clinicians should consider EDS type IV in the differential diagnosis for bilateral pneumothorax in conjunction with distinct previous histories and radiological findings. PMID:26666608

  20. The first genetically confirmed Japanese patient with mucolipidosis type IV.

    PubMed

    Saijo, Harumi; Hayashi, Masaharu; Ezoe, Takanori; Ohba, Chihiro; Saitsu, Hirotomo; Kurata, Kiyoko; Matsumoto, Naomichi

    2016-05-01

    Mucolipidosis type IV (MLIV) is a rare neurodegenerative disorder characterized by severe psychomotor delay and visual impairment. We report the brain pathology in the first Japanese patient of MLIV with a novel homozygous missense mutation in MCOLN1. We detected the localized increase in p62-reactive astrocytes in the basal ganglia. PMID:27190617

  1. Archaeal type IV pili and their involvement in biofilm formation

    PubMed Central

    Pohlschroder, Mechthild; Esquivel, Rianne N.

    2015-01-01

    Type IV pili are ancient proteinaceous structures present on the cell surface of species in nearly all bacterial and archaeal phyla. These filaments, which are required for a diverse array of important cellular processes, are assembled employing a conserved set of core components. While type IV pilins, the structural subunits of pili, share little sequence homology, their signal peptides are structurally conserved allowing for in silico prediction. Recently, in vivo studies in model archaea representing the euryarchaeal and crenarchaeal kingdoms confirmed that several of these pilins are incorporated into type IV adhesion pili. In addition to facilitating surface adhesion, these in vivo studies also showed that several predicted pilins are required for additional functions that are critical to biofilm formation. Examples include the subunits of Sulfolobus acidocaldarius Ups pili, which are induced by exposure to UV light and promote cell aggregation and conjugation, and a subset of the Haloferax volcanii adhesion pilins, which play a critical role in microcolony formation while other pilins inhibit this process. The recent discovery of novel pilin functions such as the ability of haloarchaeal adhesion pilins to regulate swimming motility may point to novel regulatory pathways conserved across prokaryotic domains. In this review, we will discuss recent advances in our understanding of the functional roles played by archaeal type IV adhesion pili and their subunits, with particular emphasis on their involvement in biofilm formation. PMID:25852657

  2. Space Telescope and Optical Reverberation Mapping Project. IV. Anomalous Behavior of the Broad Ultraviolet Emission Lines in NGC 5548

    NASA Astrophysics Data System (ADS)

    Goad, M. R.; Korista, K. T.; De Rosa, G.; Kriss, G. A.; Edelson, R.; Barth, A. J.; Ferland, G. J.; Kochanek, C. S.; Netzer, H.; Peterson, B. M.; Bentz, M. C.; Bisogni, S.; Crenshaw, D. M.; Denney, K. D.; Ely, J.; Fausnaugh, M. M.; Grier, C. J.; Gupta, A.; Horne, K. D.; Kaastra, J.; Pancoast, A.; Pei, L.; Pogge, R. W.; Skielboe, A.; Starkey, D.; Vestergaard, M.; Zu, Y.; Anderson, M. D.; Arévalo, P.; Bazhaw, C.; Borman, G. A.; Boroson, T. A.; Bottorff, M. C.; Brandt, W. N.; Breeveld, A. A.; Brewer, B. J.; Cackett, E. M.; Carini, M. T.; Croxall, K. V.; Dalla Bontà, E.; De Lorenzo-Cáceres, A.; Dietrich, M.; Efimova, N. V.; Evans, P. A.; Filippenko, A. V.; Flatland, K.; Gehrels, N.; Geier, S.; Gelbord, J. M.; Gonzalez, L.; Gorjian, V.; Grupe, D.; Hall, P. B.; Hicks, S.; Horenstein, D.; Hutchison, T.; Im, M.; Jensen, J. J.; Joner, M. D.; Jones, J.; Kaspi, S.; Kelly, B. C.; Kennea, J. A.; Kim, M.; Kim, S. C.; Klimanov, S. A.; Lee, J. C.; Leonard, D. C.; Lira, P.; MacInnis, F.; Manne-Nicholas, E. R.; Mathur, S.; McHardy, I. M.; Montouri, C.; Musso, R.; Nazarov, S. V.; Norris, R. P.; Nousek, J. A.; Okhmat, D. N.; Papadakis, I.; Parks, J. R.; Pott, J.-U.; Rafter, S. E.; Rix, H.-W.; Saylor, D. A.; Schimoia, J. S.; Schnülle, K.; Sergeev, S. G.; Siegel, M.; Spencer, M.; Sung, H.-I.; Teems, K. G.; Treu, T.; Turner, C. S.; Uttley, P.; Villforth, C.; Weiss, Y.; Woo, J.-H.; Yan, H.; Young, S.; Zheng, W.-K.

    2016-06-01

    During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert 1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far UV continuum and broad emission line variations decorrelated for ∼60–70 days, starting ∼75 days after the first HST/COS observation. Following this anomalous state, the flux and variability of the broad emission lines returned to a more normal state. This transient behavior, characterized by significant deficits in flux and equivalent width of the strong broad UV emission lines, is the first of its kind to be unambiguously identified in an active galactic nucleus reverberation mapping campaign. The largest corresponding emission line flux deficits occurred for the high ionization, collisionally excited lines C iv and Si iv(+O iv]), and also He ii(+O iii]), while the anomaly in Lyα was substantially smaller. This pattern of behavior indicates a depletion in the flux of photons with {E}{{ph}}\\gt 54 {{eV}} relative to those near 13.6 eV. We suggest two plausible mechanisms for the observed behavior: (i) temporary obscuration of the ionizing continuum incident upon broad line region (BLR) clouds by a moving veil of material lying between the inner accretion disk and inner (BLR), perhaps resulting from an episodic ejection of material from the disk, or (ii) a temporary change in the intrinsic ionizing continuum spectral energy distribution resulting in a deficit of ionizing photons with energies >54 eV, possibly due to a transient restructuring of the Comptonizing atmosphere above the disk. Current evidence appears to favor the latter explanation.

  3. Respiratory complications of Ehlers-Danlos syndrome type IV.

    PubMed

    Hatake, Katsuhiko; Morimura, Yoshifumi; Kudo, Risa; Kawashima, Wataru; Kasuda, Shogo; Kuniyasu, Hiroki

    2013-01-01

    We describe a case of Ehlers-Danlos syndrome (EDS) type IV in a male in early half in his twenties, who experienced recurrent and eventually fatal pulmonary hemorrhage. EDS type IV is a rare disorder of type III collagen synthesis that is characterized by unusual facies, thin translucent skin with a venous vascular pattern, easy bruising, and hypermobility of the small joints. Autopsy findings showed hypermobility of the joints and distensibility of the skin. Microscopically, the abdominal skin showed substantially decreased dermal thickness. Moreover, the reticular dermis showed fine collagen bundles and large interstitial spaces compared with the skin from a normal control that showed large collagen bundles. Individual elastic fibers were also thicker than those observed in the skin of a normal control. The thoracic aorta showed thin adventitia and a relative increase in elastic fibers. The parenchyma of both the lungs showed markedly diffuse hemorrhage with hemosiderin-laden alveolar macrophages or old thrombi and organized thrombi in the small bronchi. Furthermore, both sections of the lung showed multiple fibrous nodules containing benign metaplastic bone. Vascular wall disruption and tearing of the vessel walls in the lung parenchyma were also observed. We concluded that EDS type IV led to the patient's death because of pulmonary hemorrhage. Because this syndrome resulted in the patient's death from arterial and bowel rupture, it is important to consider EDS as a potential cause of sudden death. PMID:22940417

  4. Expression cloning of a candidate gene for Mucolipidosis type IV

    SciTech Connect

    Gama Sosa, M.A.; De Gasperi, R.; Battistini, S.

    1994-09-01

    Mucolipidosis IV is an autosomal recessive lysosomal storage disease characterized by progressive psychomotor retardation and opthalmological abnormalities, namely corneal opacity and retinal degeneration. Biochemically, it is characterized by the lysosomal accumulation of diverse compounds such as gangliosides, phospholipids and acidic mucopolysaccharides. To date, the basic biochemical defect causing this storage disease is still unknown and the relevant gene has also not been identified. An expression cloning strategy was used to identify human kidney cDNA clones capable of reverting in transient gene expression assays the PAS+ phenotype typical of Mucolipidosis IV cells to the normal PAS- phenotype. By this method, a candidate cDNA clone (Mu cDNA) capable of clearing Mucolipidosis IV fibroblasts of their PAS+ positive storage material was isolated. Nucleotide sequence analysis indicated the presence of 2 open reading frames. In vitro translation of T7 transcribed Mu RNA showed protein products of 7,000 and 6,000 mw. Altered expression of the Mu gene may result in the onset of Mucolipidosis type IV.

  5. Terminal ileum gangrene secondary to a type IV paraesophageal hernia

    PubMed Central

    Hsu, Ching Tsai; Hsiao, Po Jen; Chiu, Chih Chien; Chan, Jenq Shyong; Lin, Yee Fung; Lo, Yuan Hung; Hsiao, Chia Jen

    2016-01-01

    Type IV paraesophageal hernia (PEH) is very rare, and is characterized by the intrathoracic herniation of the abdominal viscera other than the stomach into the chest. We describe a 78-year-old woman who presented at our emergency department because of epigastric pain that she had experienced over the past 24 h. On the day after admission, her pain became severe and was accompanied by right chest pain and dyspnea. Chest radiography revealed an intrathoracic intestinal gas bubble occupying the right lower lung field. Emergency explorative laparotomy identified a type IV PEH with herniation of only the terminal ileum through a hiatal defect into the right thoracic cavity. In this report, we also present a review of similar cases in the literature published between 1980 and 2015 in PubMed. There were four published cases of small bowel herniation into the thoracic cavity during this period. Our patient represents a rare case of an individual diagnosed with type IV PEH with incarceration of only the terminal ileum. PMID:26937153

  6. Isoform switching of type IV collagen is developmentally arrested in X-linked Alport syndrome leading to increased susceptibility of renal basement membranes to endoproteolysis.

    PubMed Central

    Kalluri, R; Shield, C F; Todd, P; Hudson, B G; Neilson, E G

    1997-01-01

    Normal glomerular capillaries filter plasma through a basement membrane (GBM) rich in alpha3(IV), alpha4(IV), and alpha5(IV) chains of type IV collagen. We now show that these latter isoforms are absent biochemically from the glomeruli in patients with X-linked Alport syndrome (XAS). Their GBM instead retain a fetal distribution of alpha1(IV) and alpha2(IV) isoforms because they fail to developmentally switch their alpha-chain use. The anomalous persistence of these fetal isoforms of type IV collagen in the GBM in XAS also confers an unexpected increase in susceptibility to proteolytic attack by collagenases and cathepsins. The incorporation of cysteine-rich alpha3(IV), alpha4(IV), and alpha5(IV) chains into specialized basement membranes like the GBM may have normally evolved to protectively enhance their resistance to proteolytic degradation at the site of glomerular filtration. The relative absence of these potentially protective collagen IV isoforms in GBM from XAS may explain the progressive basement membrane splitting and increased damage as these kidneys deteriorate. PMID:9153291

  7. Bacteria turn on surfaces by oversteering with Type IV pili

    NASA Astrophysics Data System (ADS)

    Jin, Fan; Conrad, Jacinta C.; Gibiansky, Maxsim L.; Wong, Gerard C. L.

    2011-03-01

    Type-IV pili (TFP) are linear nano-actuators that enable bacteria to crawl on surfaces. Analysis of TFP-mediated crawling in P. aeruginosa reveals that it always alternates between two types of distinct movements: a linear translation of constant velocity is followed by a combined translation-rotation that is ~ 10 x faster in instantaneous velocity. The latter process can turn the cell body by over-steering so that the rear of the cell loses traction with the surface. Orientational distributions of these movements suggest that the former is due to pulling by multiple TFP, whereas the latter is mostly due to release by single TFP.

  8. Adult presentation of Bartter syndrome type IV with erythrocytosis

    PubMed Central

    Heilberg, Ita Pfeferman; Tótoli, Cláudia; Calado, Joaquim Tomaz

    2015-01-01

    Abstract Bartter syndrome comprises a group of rare autosomal-recessive salt-losing disorders with distinct phenotypes, but one unifying pathophysiology consisting of severe reductions of sodium reabsorption caused by mutations in five genes expressed in the thick ascending limb of Henle, coupled with increased urinary excretion of potassium and hydrogen, which leads to hypokalemic alkalosis. Bartter syndrome type IV, caused by loss-of-function mutations in barttin, a subunit of chloride channel CLC-Kb expressed in the kidney and inner ear, usually occurs in the antenatal-neonatal period. We report an unusual case of late onset presentation of Bartter syndrome IV and mild phenotype in a 20 years-old man who had hypokalemia, deafness, secondary hyperparathyroidism and erythrocytosis. PMID:26537508

  9. Anomalous Elastic Behavior in hcp- and Sm-Type Dysprosium

    SciTech Connect

    Tschauner, Oliver; Grubor-Urosevic, Ognjen; Dera, Przemyslaw; Mulcahy, Sean R.

    2012-04-11

    The compression behavior of elemental dysprosium in the hcp- and the Sm-type phases has been examined under hydrostatic pressure. Sm-type Dy has been found about 1% denser than the hcp phase. This increase in density is due to c-axis contraction in Sm-type Dy, whereas the a-axis even expands compared with the hcp-phase. Both the hcp- and the Sm-type phases show an inversion in the pressure derivative of the c/a ratio. For hcp-Dy this inversion is very sharp with minimal c/a at 2.5 GPa. At the same pressure, the compression behavior of hcp-Dy changes abruptly from dominantly c-axis compression to almost isotropic compression with slightly softer S{sub 11}. The bulk modulus increases at this point by a factor of {approx}2. Both hcp- and Sm-type Dy exhibit a crossover from highly anisotropic compression mostly along the c-axis to almost isotropic compression. We discuss these anomalies with respect to a possible Lifshitz transition and structural soft modes.

  10. Anomalous absorption in a-type asymmetric top molecules in cosmic objects

    NASA Astrophysics Data System (ADS)

    Chandra, Suresh

    Since the detection of the first molecule OH in cosmic objects in 1963, scientists got interested in identification of molecules in the cosmic objects. By now more than 170 molecules have been identified. In order to know about the physical conditions prevailing in the cool cosmic objects and about the chemical reactions going on there, scientists are interested in identification of as many molecules as possible. In some molecular clouds, the kinetic temperature is very low, 10 - 20 K. For such objects, anomalous absorption, i.e., the absorption against the cosmic microwave background, may play an important role for identification of molecules. The transition 111 - 110 at 4.829 GHz of H_2CO was the first one showing the anomalous absorption in the cosmic objects. The molecule H_2CS also has been identified in the cosmic objects. We have discussed about the anomalous absorption of 111 - 110 transition in a-type asymmetric top molecules. For the investigation, the required parameters are the radiative and collisional transition probabilities. We can calculate radiative transition probabilities between the rotational levels. Calculation of collisional rates is a tedious job. In absence of accurate collisional rates, we can investigated the anomalous absorption in a qualitative manner by using the scaled values for collisional rates. We find that anomalous absorption of 111 - 110 transition is possible, provided collisional rates satisfy the required condition.

  11. Mechanical stability study of type IV cryomodule (ILC prototype)

    SciTech Connect

    McGee, M.W.; Doremus, R.; Wands, C.R.; /Fermilab

    2007-06-01

    An ANSYS modal and harmonic finite element analysis (FEA) was performed in order to investigate cryomodule design mechanical stability for the proposed International Linear Collider (ILC). The current cryomodule, designated Type IV or (T4CM), closely follows the Type III TESLA Test Facility (TTF) version used at DESY, with the exception of a proposed location of the superconducting (SC) quadrupole at the center. This analysis considered the stringent stability criteria established for the ILC, where vertical motion for the SC quadrupole is limited to the micron range at a few Hz. Model validation was achieved through Type III cryomodule vibration measurement studies performed at DESY. The effect of support location, support stiffness and other important parameters were considered in a parametric sensitivity study. FEA results, fast motion investigations and stabilization techniques are discussed.

  12. A force-dependent switch reverses type IV pilus retraction.

    PubMed

    Maier, Berenike; Koomey, Michael; Sheetz, Michael P

    2004-07-27

    Type IV pilus dynamics is important for virulence, motility, and DNA transfer in a wide variety of prokaryotes. The type IV pilus system constitutes a very robust and powerful molecular machine that transports pilus polymers as well as DNA through the bacterial cell envelope. In Neisseria gonorrhoeae, pilus retraction is a highly irreversible process that depends on PilT, an AAA ATPase family member. However, when levels of PilT are reduced, the application of high external forces (F = 110 +/- 10 pN) induces processive pilus elongation. At forces of >50 pN, single pili elongate at a rate of v = 350 +/- 50 nm/s. For forces of <50 pN, elongation velocity depends strongly on force and relaxation causes immediate retraction. Both pilus retraction and force-induced elongation can be modeled by chemical kinetics with same step length for the rate-limiting translocation step. The model implies that a force-dependent molecular switch can induce pilus elongation by reversing the retraction mechanism. PMID:15256598

  13. F-Area Type IV Tank Liner Life Estimation

    SciTech Connect

    Wiersman, B. J.

    2005-10-01

    The Savannah River Site (SRS) is proceeding with closure of the Type IV waste tanks that are located in F-area. These tanks are underground concrete vaults and have been in service since the early 1960's. The interior of the concrete vault is lined with carbon steel plate. The time necessary for the carbon steel plate to disintegrate was estimated. These calculations assumed that the concrete structure was degraded and therefore the exterior of the liner is exposed to the soil conditions. Two corrosion mechanisms were examined: pitting and general corrosion. Data from soil corrosion studies performed by the National Bureau of Standards (NBS) was utilized to estimate the corrosion rate of the carbon steel liner. The following conclusions were made: (1) Cecil Clay Loam in Atlanta, Georgia, a soil tested by the NBS, is representative of the SRS soil conditions near the F-Area Type IV tanks. (2) The time to tank wall disintegration due to general corrosion only was estimated to be 770 years after concrete vault failure. (3) The time to tank wall disintegration due to pitting corrosion was estimated to be 675 years after concrete vault failure. (4) The lower bound estimate for the time to tank wall disintegration is 675 years.

  14. Named entity recognition for bacterial Type IV secretion systems.

    PubMed

    Ananiadou, Sophia; Sullivan, Dan; Black, William; Levow, Gina-Anne; Gillespie, Joseph J; Mao, Chunhong; Pyysalo, Sampo; Kolluru, Balakrishna; Tsujii, Junichi; Sobral, Bruno

    2011-01-01

    Research on specialized biological systems is often hampered by a lack of consistent terminology, especially across species. In bacterial Type IV secretion systems genes within one set of orthologs may have over a dozen different names. Classifying research publications based on biological processes, cellular components, molecular functions, and microorganism species should improve the precision and recall of literature searches allowing researchers to keep up with the exponentially growing literature, through resources such as the Pathosystems Resource Integration Center (PATRIC, patricbrc.org). We developed named entity recognition (NER) tools for four entities related to Type IV secretion systems: 1) bacteria names, 2) biological processes, 3) molecular functions, and 4) cellular components. These four entities are important to pathogenesis and virulence research but have received less attention than other entities, e.g., genes and proteins. Based on an annotated corpus, large domain terminological resources, and machine learning techniques, we developed recognizers for these entities. High accuracy rates (>80%) are achieved for bacteria, biological processes, and molecular function. Contrastive experiments highlighted the effectiveness of alternate recognition strategies; results of term extraction on contrasting document sets demonstrated the utility of these classes for identifying T4SS-related documents. PMID:21468321

  15. Ehlers-Danlos Syndrome Type IV: A Case Report.

    PubMed

    Soo-Hoo, Sarah; Porten, Brandon R; Engstrom, Bjorn I; Skeik, Nedaa

    2016-04-01

    Ehlers-Danlos syndrome (EDS) encompasses a group of rare genetic connective tissue disorders. The vascular type (type IV) poses the most serious risk to patients. Diagnosis is usually difficult, especially if patients lack a family history. Life-threatening vascular emergency such as dissection or rupture can be the first presenting symptom. Management of the disease can pose a clinical challenge due to the emergency of presentation, tissue friability, and lack of clear management recommendations. We report a unique case of a 40-year-old man who presented with a ruptured celiac artery and a strong family history of EDS. This case highlights the difficulties and complications associated with treating this uncommon and serious disease. PMID:26975607

  16. Identification of mutations in Type IV glycogen storage disease

    SciTech Connect

    Bao, Y.; Kishnani, P.; Chen, Y.T.

    1994-09-01

    Type IV glycogen storage disease (GSD IV, Andersen disease) is caused by a deficiency of glycogen branching enzyme (GBE) activity, which results in the accumulation of glycogen with unbranched, long, outer chains in the tissues. The molecular basis of the disease is not known. We studied four patients with the disease; three with typical presentation of progressive liver cirrhosis and failure, and one with severe and fatal neonatal hypotonia and cardiomyopathy. Southern blot analysis with EcoRI or MspI did not detect gross DNA rearrangement, deletion or duplication in patients` glycogen branching enzyme genes. Northern analysis with total cellular RNAs isolated from skin fibroblast MI strains of three patients with typical clinical presentation showed a normal level and size (2.95 kb) of GBE mRNA hybridization band in two and absent mRNA hybridization band in the remaining one. The patient with atypical severe neonatal hypotonia demonstrated a less intense and smaller size (2.75 kb) of mRNA hybridization band. A 210 hp deletion from nucleotide sequence 873 to 1082 which causes 70 amino acids missing from amino acid sequence 262 to 331 was detected in all 17 clones sequenced from the fatal hypotonia patient. This deletion is located in the region which is highly conserved between prokaryotic, yeast and human GBE polypeptide sequences, and also includes the first of the four regions which constitute the catalytic active sites of most of amylolytic enzymes. A point mutation C-T (1633) which changes the amino acid from Arginine to Cystine was found in 19 of 20 cDNA clones from a patient with classical clinical presentation. This point mutation was unique to this patient and was not observed in three other patients or normal controls. This is the first report on the molecular basis of GSD IV and our data indicated the presence of extensive genetic heterogeneity in the disease.

  17. Identification of Anaplasma marginale Type IV Secretion System Effector Proteins

    PubMed Central

    Brayton, Kelly A.; Beare, Paul A.; Brown, Wendy C.; Heinzen, Robert A.; Broschat, Shira L.

    2011-01-01

    Background Anaplasma marginale, an obligate intracellular alphaproteobacterium in the order Rickettsiales, is a tick-borne pathogen and the leading cause of anaplasmosis in cattle worldwide. Complete genome sequencing of A. marginale revealed that it has a type IV secretion system (T4SS). The T4SS is one of seven known types of secretion systems utilized by bacteria, with the type III and IV secretion systems particularly prevalent among pathogenic Gram-negative bacteria. The T4SS is predicted to play an important role in the invasion and pathogenesis of A. marginale by translocating effector proteins across its membrane into eukaryotic target cells. However, T4SS effector proteins have not been identified and tested in the laboratory until now. Results By combining computational methods with phylogenetic analysis and sequence identity searches, we identified a subset of potential T4SS effectors in A. marginale strain St. Maries and chose six for laboratory testing. Four (AM185, AM470, AM705 [AnkA], and AM1141) of these six proteins were translocated in a T4SS-dependent manner using Legionella pneumophila as a reporter system. Conclusions The algorithm employed to find T4SS effector proteins in A. marginale identified four such proteins that were verified by laboratory testing. L. pneumophila was shown to work as a model system for A. marginale and thus can be used as a screening tool for A. marginale effector proteins. The first T4SS effector proteins for A. marginale have been identified in this work. PMID:22140462

  18. Role of Type IV Pili in Predation by Bdellovibrio bacteriovorus

    PubMed Central

    Chanyi, Ryan M.; Koval, Susan F.

    2014-01-01

    Bdellovibrio bacteriovorus, as an obligate predator of Gram-negative bacteria, requires contact with the surface of a prey cell in order to initiate the life cycle. After attachment, the predator penetrates the prey cell outer membrane and enters the periplasmic space. Attack phase cells of B. bacteriovorus have polar Type IV pili that are required for predation. In other bacteria, these pili have the ability to extend and retract via the PilT protein. B. bacteriovorus has two pilT genes, pilT1 and pilT2, that have been implicated in the invasion process. Markerless in-frame deletion mutants were constructed in a prey-independent mutant to assess the role of PilT1 and PilT2 in the life cycle. When predation was assessed using liquid cocultures, all mutants produced bdelloplasts of Escherichia coli. These results demonstrated that PilT1 and PilT2 are not required for invasion of prey cells. Predation of the mutants on biofilms of E. coli was also assessed. Wild type B. bacteriovorus 109JA and the pilT1 mutant decreased the mass of the biofilm to 35.4% and 27.9% respectively. The pilT1pilT2 mutant was able to prey on the biofilm, albeit less efficiently with 50.2% of the biofilm remaining. The pilT2 mutant was unable to disrupt the biofilm, leaving 92.5% of the original biofilm after predation. The lack of PilT2 function may impede the ability of B. bacteriovorus to move in the extracellular polymeric matrix and find a prey cell. The role of Type IV pili in the life cycle of B. bacteriovorus is thus for initial recognition of and attachment to a prey cell in liquid cocultures, and possibly for movement within the matrix of a biofilm. PMID:25409535

  19. Bacterial Type IV Secretion Systems: Versatile Virulence Machines

    PubMed Central

    Voth, Daniel E.; Broederdorf, Laura J.; Graham, Joseph G.

    2013-01-01

    Many bacterial pathogens employ multicomponent protein complexes to deliver macromolecules directly into their eukaryotic host cell to promote infection. Some Gram-negative pathogens use a versatile type IV secretion system (T4SS) that can translocate DNA or proteins into host cells. T4SSs represent major bacterial virulence determinants and have recently been the focus of intense research efforts designed to better understand and combat infectious diseases. Interestingly, although the two major classes of T4SSs function in a similar manner to secrete proteins, the translocated “effectors” vary substantially from one organism to another. In fact, differing effector repertoires likely contribute to organism-specific host cell interactions and disease outcomes. In this review, we discuss the current state of T4SS research, with an emphasis on intracellular bacterial pathogens of humans and the diverse array of translocated effectors used to manipulate host cells. PMID:22324993

  20. Type IV pili promote early biofilm formation by Clostridium difficile.

    PubMed

    Maldarelli, Grace A; Piepenbrink, Kurt H; Scott, Alison J; Freiberg, Jeffrey A; Song, Yang; Achermann, Yvonne; Ernst, Robert K; Shirtliff, Mark E; Sundberg, Eric J; Donnenberg, Michael S; von Rosenvinge, Erik C

    2016-08-01

    Increasing morbidity and mortality from Clostridium difficile infection (CDI) present an enormous challenge to healthcare systems. Clostridium difficile express type IV pili (T4P), but their function remains unclear. Many chronic and recurrent bacterial infections result from biofilms, surface-associated bacterial communities embedded in an extracellular matrix. CDI may be biofilm mediated; T4P are important for biofilm formation in a number of organisms. We evaluate the role of T4P in C. difficile biofilm formation using RNA sequencing, mutagenesis and complementation of the gene encoding the major pilin pilA1, and microscopy. RNA sequencing demonstrates that, in comparison to other growth phenotypes, C. difficile growing in a biofilm has a distinct RNA expression profile, with significant differences in T4P gene expression. Microscopy of T4P-expressing and T4P-deficient strains suggests that T4P play an important role in early biofilm formation. A non-piliated pilA1 mutant forms an initial biofilm of significantly reduced mass and thickness in comparison to the wild type. Complementation of the pilA1 mutant strain leads to formation of a biofilm which resembles the wild-type biofilm. These findings suggest that T4P play an important role in early biofilm formation. Novel strategies for confronting biofilm infections are emerging; our data suggest that similar strategies should be investigated in CDI. PMID:27369898

  1. Minor Type IV Collagen α5 Chain Promotes Cancer Progression through Discoidin Domain Receptor-1

    PubMed Central

    Xiao, Qian; Jiang, Yan; Liu, Qingbo; Yue, Jiao; Liu, Chunying; Zhao, Xiaotong; Qiao, Yuemei; Ji, Hongbin; Chen, Jianfeng; Ge, Gaoxiang

    2015-01-01

    Type IV collagens (Col IV), components of basement membrane, are essential in the maintenance of tissue integrity and proper function. Alteration of Col IV is related to developmental defects and diseases, including cancer. Col IV α chains form α1α1α2, α3α4α5 and α5α5α6 protomers that further form collagen networks. Despite knowledge on the functions of major Col IV (α1α1α2), little is known whether minor Col IV (α3α4α5 and α5α5α6) plays a role in cancer. It also remains to be elucidated whether major and minor Col IV are functionally redundant. We show that minor Col IV α5 chain is indispensable in cancer development by using α5(IV)-deficient mouse model. Ablation of α5(IV) significantly impeded the development of KrasG12D-driven lung cancer without affecting major Col IV expression. Epithelial α5(IV) supports cancer cell proliferation, while endothelial α5(IV) is essential for efficient tumor angiogenesis. α5(IV), but not α1(IV), ablation impaired expression of non-integrin collagen receptor discoidin domain receptor-1 (DDR1) and downstream ERK activation in lung cancer cells and endothelial cells. Knockdown of DDR1 in lung cancer cells and endothelial cells phenocopied the cells deficient of α5(IV). Constitutively active DDR1 or MEK1 rescued the defects of α5(IV)-ablated cells. Thus, minor Col IV α5(IV) chain supports lung cancer progression via DDR1-mediated cancer cell autonomous and non-autonomous mechanisms. Minor Col IV can not be functionally compensated by abundant major Col IV. PMID:25992553

  2. Hereditary sensory and autonomic neuropathies: types II, III, and IV.

    PubMed

    Axelrod, Felicia B; Gold-von Simson, Gabrielle

    2007-01-01

    The hereditary sensory and autonomic neuropathies (HSAN) encompass a number of inherited disorders that are associated with sensory dysfunction (depressed reflexes, altered pain and temperature perception) and varying degrees of autonomic dysfunction (gastroesophageal reflux, postural hypotention, excessive sweating). Subsequent to the numerical classification of four distinct forms of HSAN that was proposed by Dyck and Ohta, additional entities continue to be described, so that identification and classification are ongoing. As a group, the HSAN are rare diseases that affect both sexes. HSAN III is almost exclusive to individuals of Eastern European Jewish extraction, with incidence of 1 per 3600 live births. Several hundred cases with HSAN IV have been reported. The worldwide prevalence of HSAN type II is very low. This review focuses on the description of three of the disorders, HSAN II through IV, that are characterized by autosomal recessive inheritance and onset at birth. These three forms of HSAN have been the most intensively studied, especially familial dysautonomia (Riley-Day syndrome or HSAN III), which is often used as a prototype for comparison to the other HSAN. Each HSAN disorder is likely caused by different genetic errors that affect specific aspects of small fiber neurodevelopment, which result in variable phenotypic expression. As genetic tests are routinely used for diagnostic confirmation of HSAN III only, other means of differentiating between the disorders is necessary. Diagnosis is based on the clinical features, the degree of both sensory and autonomic dysfunction, and biochemical evaluations, with pathologic examinations serving to further confirm differences. Treatments for all these disorders are supportive. PMID:17915006

  3. Hereditary sensory and autonomic neuropathies: types II, III, and IV

    PubMed Central

    Axelrod, Felicia B; Gold-von Simson, Gabrielle

    2007-01-01

    The hereditary sensory and autonomic neuropathies (HSAN) encompass a number of inherited disorders that are associated with sensory dysfunction (depressed reflexes, altered pain and temperature perception) and varying degrees of autonomic dysfunction (gastroesophageal reflux, postural hypotention, excessive sweating). Subsequent to the numerical classification of four distinct forms of HSAN that was proposed by Dyck and Ohta, additional entities continue to be described, so that identification and classification are ongoing. As a group, the HSAN are rare diseases that affect both sexes. HSAN III is almost exclusive to individuals of Eastern European Jewish extraction, with incidence of 1 per 3600 live births. Several hundred cases with HSAN IV have been reported. The worldwide prevalence of HSAN type II is very low. This review focuses on the description of three of the disorders, HSAN II through IV, that are characterized by autosomal recessive inheritance and onset at birth. These three forms of HSAN have been the most intensively studied, especially familial dysautonomia (Riley-Day syndrome or HSAN III), which is often used as a prototype for comparison to the other HSAN. Each HSAN disorder is likely caused by different genetic errors that affect specific aspects of small fiber neurodevelopment, which result in variable phenotypic expression. As genetic tests are routinely used for diagnostic confirmation of HSAN III only, other means of differentiating between the disorders is necessary. Diagnosis is based on the clinical features, the degree of both sensory and autonomic dysfunction, and biochemical evaluations, with pathologic examinations serving to further confirm differences. Treatments for all these disorders are supportive. PMID:17915006

  4. Type IV Pili in Gram-Positive Bacteria

    PubMed Central

    Craig, Lisa

    2013-01-01

    SUMMARY Type IV pili (T4P) are surface-exposed fibers that mediate many functions in bacteria, including locomotion, adherence to host cells, DNA uptake (competence), and protein secretion and that can act as nanowires carrying electric current. T4P are composed of a polymerized protein, pilin, and their assembly apparatuses share protein homologs with type II secretion systems in eubacteria and the flagella of archaea. T4P are found throughout Gram-negative bacterial families and have been studied most extensively in certain model Gram-negative species. Recently, it was discovered that T4P systems are also widespread among Gram-positive species, in particular the clostridia. Since Gram-positive and Gram-negative bacteria have many differences in cell wall architecture and other features, it is remarkable how similar the T4P core proteins are between these organisms, yet there are many key and interesting differences to be found as well. In this review, we compare the two T4P systems and identify and discuss the features they have in common and where they differ to provide a very broad-based view of T4P systems across all eubacterial species. PMID:24006467

  5. Heterogeneity among specific phobia types in DSM-IV.

    PubMed

    Antony, M M; Brown, T A; Barlow, D H

    1997-12-01

    Recently, it has been suggested that situational specific phobias (e.g., phobias of driving, flying, enclosed places) are more closely related to agoraphobia than are other specific phobia types. The present study investigated this hypothesis by examining heterogeneity among the four main DSM-IV specific phobia types, particularly with respect to variables believed to be associated with agoraphobia. Using interviews and behavioral testing, 60 patients with specific phobias of animals, heights, blood/injections, or driving were compared with respect to etiology, age of onset, physiological response, predictability of panic attacks, and focus of apprehension. Fifteen patients suffering from panic disorder with agoraphobia served as a comparison group for some measures. Relative to the other specific phobias, driving phobias were most strongly associated with a later age of onset, similar to that of individuals with agoraphobia. Height phobias were also associated with a late age of onset as well as a more internal focus of apprehension, relative to other groups. Finally, individuals in the blood/injection phobia group reported a more internal focus of apprehension than those in other groups and were the only group to report a history of fainting in the phobic situation. Overall, the results did not support the hypothesis that situational phobias are a variant of agoraphobia. In fact, on several of the variables for which groups did differ, individuals with height phobias (a phobia from the natural environment type) showed a pattern most similar to individuals with agoraphobia. The implications of these results for the classification of specific phobias are discussed. PMID:9465442

  6. Type IV Pilus Secretins Have Extracellular C Termini

    PubMed Central

    Lieberman, Joshua A.; Petro, Courtney D.; Thomas, Stefani; Yang, Austin

    2015-01-01

    ABSTRACT Type IV pili (T4Ps) are surface appendages used by Gram-negative and Gram-positive pathogens for motility and attachment to epithelial surfaces. In Gram-negative bacteria, such as the important pediatric pathogen enteropathogenic Escherichia coli (EPEC), during extension and retraction, the pilus passes through an outer membrane (OM) pore formed by the multimeric secretin complex. The secretin is common to Gram-negative assemblies, including the related type 2 secretion (T2S) system and the type 3 secretion (T3S) system. The N termini of the secretin monomers are periplasmic and in some systems have been shown to mediate substrate specificity. In this study, we mapped the topology of BfpB, the T4P secretin from EPEC, using a combination of biochemical and biophysical techniques that allowed selective identification of periplasmic and extracellular residues. We applied rules based on solved atomic structures of outer membrane proteins (OMPs) to generate our topology model, combining the experimental results with secondary structure prediction algorithms and direct inspection of the primary sequence. Surprisingly, the C terminus of BfpB is extracellular, a result confirmed by flow cytometry for BfpB and a distantly related T4P secretin, PilQ, from Pseudomonas aeruginosa. Keeping with prior evidence, the C termini of two T2S secretins and one T3S secretin were not detected on the extracellular surface. On the basis of our data and structural constraints, we propose that BfpB forms a beta barrel with 16 transmembrane beta strands. We propose that the T4P secretins have a C-terminal segment that passes through the center of each monomer. PMID:25805731

  7. Structure of Clostridium difficile PilJ Exhibits Unprecedented Divergence from Known Type IV Pilins*

    PubMed Central

    Piepenbrink, Kurt H.; Maldarelli, Grace A.; de la Peña, Claudia F. Martinez; Mulvey, George L.; Snyder, Greg A.; De Masi, Leon; von Rosenvinge, Erik C.; Günther, Sebastian; Armstrong, Glen D.; Donnenberg, Michael S.; Sundberg, Eric J.

    2014-01-01

    Type IV pili are produced by many pathogenic Gram-negative bacteria and are important for processes as diverse as twitching motility, cellular adhesion, and colonization. Recently, there has been an increased appreciation of the ability of Gram-positive species, including Clostridium difficile, to produce Type IV pili. Here we report the first three-dimensional structure of a Gram-positive Type IV pilin, PilJ, demonstrate its incorporation into Type IV pili, and offer insights into how the Type IV pili of C. difficile may assemble and function. PilJ has several unique structural features, including a dual-pilin fold and the incorporation of a structural zinc ion. We show that PilJ is incorporated into Type IV pili in C. difficile and present a model in which the incorporation of PilJ into pili exposes the C-terminal domain of PilJ to create a novel interaction surface. PMID:24362261

  8. Mechanical Properties of Type IV Pili in P. Aeruginosa

    NASA Astrophysics Data System (ADS)

    Lu, Shun; Touhami, Ahmed; Scheurwater, Edie; Harvey, Hanjeong; Burrows, Lori; Dutcher, John

    2009-03-01

    Type IV pili (Tfp) are thin flexible protein filaments that extend from the cell membrane of bacteria such as Pseudomonas aeruginosa and Neisseria gonorrhoeae. The mechanical properties of Tfp are of great importance since they allow bacteria to interact with and colonize various surfaces. In the present study, we have used atomic force microscopy (AFM) for both imaging and pulling on Tfp from P. aeruginosa (PAO1) and from its PilA, PilT, and FliC mutants. A single pilus filament was mechanically stretched and the resulting force-extension profiles were fitted using the worm-like-chain (WLC) model. The statistical distributions obtained for contour length, persistence length, and number of pili per bacteria pole, were used to evaluate the mechanical properties of a single pilus and the biogenesis functions of different proteins (PilA, PilT) involved in its assembly and disassembly. Importantly, the persistence length value of ˜ 1 μm measured in the present study, which is consistent with the curvature of the pili observed in our AFM images, is significantly lower than the value of 5 μm reported earlier by Skerker et al. (1). Our results shed new light on the role of mechanical forces that mediate bacteria-surface interactions and biofilm formation. 1- J.M. Skerker and H.C. Berg, Proc. Natl. Acad. Sci. USA, 98, 6901-6904 (2001).

  9. Characteristics of unsteady type IV shock/shock interaction

    NASA Astrophysics Data System (ADS)

    Chu, Y.-B.; Lu, X.-Y.

    2012-05-01

    Characteristics of the unsteady type IV shock/shock interaction of hypersonic blunt body flows are investigated by solving the Navier-Stokes equations with high-order numerical methods. The intrinsic relations of flow structures to shear, compression, and heating processes are studied and the physical mechanisms of the unsteady flow evolution are revealed. It is found that the instantaneous surface-heating peak is caused by the fluid in the "hot spot" generated by an oscillating and deforming jet bow shock (JBS) just ahead of the body surface. The features of local shock/boundary layer interaction and vortex/boundary layer interaction are clarified. Based on the analysis of flow evolution, it is identified that the upstream-propagating compression waves are associated with the interaction of the JBS and the shear layers formed by a supersonic impinging jet, and then the interaction of the freestream bow shocks and the compression waves results in entropy and vortical waves propagating to the body surface. Further, the feedback mechanism of the inherent unsteadiness of the flow field is revealed to be related to the impinging jet. A feedback model is proposed to reliably predict the dominant frequency of flow evolution. The results obtained in this study provide physical insight into the understanding of the mechanisms relevant to this complex flow.

  10. Narrowband frequency-drift structures in solar type IV bursts

    NASA Astrophysics Data System (ADS)

    Nishimura, Yukio; Ono, Takayuki; Tsuchiya, Fuminori; Misawa, Hiroaki; Kumamoto, Atsushi; Katoh, Yuto; Masuda, Satoshi; Miyoshi, Yoshizumi

    2013-12-01

    We have established the Zao Solar Radiospectrograph (ZSR), a new solar radio observation system, at the Zao observatory of Tohoku University, Japan. We observed narrowband fine structures with type IV bursts with ZSR on 2 and 3 November 2008. The observed fine structures are similar to fiber bursts in terms of the drift rates and the existence of emission and absorption stripes. Statistical analysis of the drift rates, however, shows that the observed fine structures are different from the ordinary fiber bursts as regards the sense and the magnitude of their drift rates. First, the observed drift rates include both positive and negative rates, whereas ordinary fiber bursts are usually characterized by negative drift rates. Second, the absolute values of the observed drift rates are tens of MHz s-1, whereas the typical drift rate of fiber bursts at 325 MHz is approximately -9 MHz s-1. In addition, all fine structures analyzed have narrow emission bands of less than 17 MHz. We also show that the observed narrowband emission features with drift rates of approximately 40 MHz s-1 can be interpreted as the propagation of whistler-mode waves, which is the same process as that underlying fiber bursts.

  11. Characterization of the Francisella tularensis subsp. novicida type IV pilus.

    PubMed

    Zogaj, Xhavit; Chakraborty, Subhra; Liu, Jirong; Thanassi, David G; Klose, Karl E

    2008-07-01

    Francisella tularensis causes the disease tularaemia. Type IV pili (Tfp) genes are present in the genomes of all F. tularensis subspecies. We show that the wild-type F. tularensis subsp. novicida expresses pilus fibres on its surface, and mutations in the Tfp genes pilF and pilT disrupt pilus biogenesis. Mutations in other Tfp genes (pilQ and pilG) do not eliminate pilus expression. A mutation in pilE4 eliminates pilus expression, whereas mutations in the other pilin subunits pilE1-3 and pilE5 do not, suggesting that pilE4 is the major pilus structural subunit. The virulence regulator MglA is required for pilus expression, and it regulates the transcription of a putative Tfp glycosylation gene (FTN0431). However, MglA does not regulate transcription of pilF, pilT or pilE4, and a strain lacking FTN0431 still expresses pili; thus, it is unclear how MglA regulates pilus expression. Only pilF was also required for protein secretion, while pilE4 and pilT were not, indicating that there is very little overlap of the protein secretion/Tfp functions of the pil genes. The protein secretion component pilE1 was more important for in vitro intramacrophage growth and mouse virulence than the Tfp component pilE4. Our results provide the first genetic characterization of the novel Tfp system of F. tularensis. PMID:18599841

  12. An Unusual Type of Totally Anomalous Pulmonary Venous Connection to the Superior Cavoatrial Junction.

    PubMed

    Shamsuddin, Ahmad Mahir; Wong, Abdul Rahim; Anderson, Robert H; Corno, Antonio F

    2016-07-01

    A neonate with cyanosis at birth was found to have a rare type of totally anomalous pulmonary venous connection. The pulmonary veins entered a confluence posterior to the left atrial wall, which drained into the right superior cavoatrial junction. There were no other major structural defects and no evidence of isomerism. Because of the severe cyanosis, and the restrictive nature of the interatrial communication, we performed balloon atrioseptostomy to improve oxygenation. We then achieved successful surgical repair when the baby was aged 7 months. PMID:26795906

  13. Structural Characterization of Novel Pseudomonas aeruginosa Type IV Pilins

    SciTech Connect

    Nguyen, Y.; Jackson, S; Aidoo, F; Junop, M; Burrows, L

    2010-01-01

    Pseudomonas aeruginosa type IV pili, composed of PilA subunits, are used for attachment and twitching motility on surfaces. P. aeruginosa strains express one of five phylogenetically distinct PilA proteins, four of which are associated with accessory proteins that are involved either in pilin posttranslational modification or in modulation of pilus retraction dynamics. Full understanding of pilin diversity is crucial for the development of a broadly protective pilus-based vaccine. Here, we report the 1.6-{angstrom} X-ray crystal structure of an N-terminally truncated form of the novel PilA from strain Pa110594 (group V), which represents the first non-group II pilin structure solved. Although it maintains the typical T4a pilin fold, with a long N-terminal {alpha}-helix and four-stranded antiparallel {beta}-sheet connected to the C-terminus by a disulfide-bonded loop, the presence of an extra helix in the {alpha}{beta}-loop and a disulfide-bonded loop with helical character gives the structure T4b pilin characteristics. Despite the presence of T4b features, the structure of PilA from strain Pa110594 is most similar to the Neisseria gonorrhoeae pilin and is also predicted to assemble into a fiber similar to the GC pilus, based on our comparative pilus modeling. Interactions between surface-exposed areas of the pilin are suggested to contribute to pilus fiber stability. The non-synonymous sequence changes between group III and V pilins are clustered in the same surface-exposed areas, possibly having an effect on accessory protein interactions. However, based on our high-confidence model of group III PilA{sub PA14}, compensatory changes allow for maintenance of a similar shape.

  14. Diversity and Evolution of Type IV pili Systems in Archaea.

    PubMed

    Makarova, Kira S; Koonin, Eugene V; Albers, Sonja-Verena

    2016-01-01

    Many surface structures in archaea including various types of pili and the archaellum (archaeal flagellum) are homologous to bacterial type IV pili systems (T4P). The T4P consist of multiple proteins, often with poorly conserved sequences, complicating their identification in sequenced genomes. Here we report a comprehensive census of T4P encoded in archaeal genomes using sensitive methods for protein sequence comparison. This analysis confidently identifies as T4P components about 5000 archaeal gene products, 56% of which are currently annotated as hypothetical in public databases. Combining results of this analysis with a comprehensive comparison of genomic neighborhoods of the T4P, we present models of organization of 10 most abundant variants of archaeal T4P. In addition to the differentiation between major and minor pilins, these models include extra components, such as S-layer proteins, adhesins and other membrane and intracellular proteins. For most of these systems, dedicated major pilin families are identified including numerous stand alone major pilin genes of the PilA family. Evidence is presented that secretion ATPases of the T4P and cognate TadC proteins can interact with different pilin sets. Modular evolution of T4P results in combinatorial variability of these systems. Potential regulatory or modulating proteins for the T4P are identified including KaiC family ATPases, vWA domain-containing proteins and the associated MoxR/GvpN ATPase, TFIIB homologs and multiple unrelated transcription regulators some of which are associated specific T4P. Phylogenomic analysis suggests that at least one T4P system was present in the last common ancestor of the extant archaea. Multiple cases of horizontal transfer and lineage-specific duplication of T4P loci were detected. Generally, the T4P of the archaeal TACK superphylum are more diverse and evolve notably faster than those of euryarchaea. The abundance and enormous diversity of T4P in hyperthermophilic archaea

  15. Diversity and Evolution of Type IV pili Systems in Archaea

    PubMed Central

    Makarova, Kira S.; Koonin, Eugene V.; Albers, Sonja-Verena

    2016-01-01

    Many surface structures in archaea including various types of pili and the archaellum (archaeal flagellum) are homologous to bacterial type IV pili systems (T4P). The T4P consist of multiple proteins, often with poorly conserved sequences, complicating their identification in sequenced genomes. Here we report a comprehensive census of T4P encoded in archaeal genomes using sensitive methods for protein sequence comparison. This analysis confidently identifies as T4P components about 5000 archaeal gene products, 56% of which are currently annotated as hypothetical in public databases. Combining results of this analysis with a comprehensive comparison of genomic neighborhoods of the T4P, we present models of organization of 10 most abundant variants of archaeal T4P. In addition to the differentiation between major and minor pilins, these models include extra components, such as S-layer proteins, adhesins and other membrane and intracellular proteins. For most of these systems, dedicated major pilin families are identified including numerous stand alone major pilin genes of the PilA family. Evidence is presented that secretion ATPases of the T4P and cognate TadC proteins can interact with different pilin sets. Modular evolution of T4P results in combinatorial variability of these systems. Potential regulatory or modulating proteins for the T4P are identified including KaiC family ATPases, vWA domain-containing proteins and the associated MoxR/GvpN ATPase, TFIIB homologs and multiple unrelated transcription regulators some of which are associated specific T4P. Phylogenomic analysis suggests that at least one T4P system was present in the last common ancestor of the extant archaea. Multiple cases of horizontal transfer and lineage-specific duplication of T4P loci were detected. Generally, the T4P of the archaeal TACK superphylum are more diverse and evolve notably faster than those of euryarchaea. The abundance and enormous diversity of T4P in hyperthermophilic archaea

  16. Clinical significance of serum laminin and type-IV collagen levels in cutaneous melanoma patients

    PubMed Central

    TAS, FARUK; BILGIN, ELIF; KARABULUT, SENEM; DURANYILDIZ, DERYA

    2016-01-01

    Laminin and type-IV collagen constitute a significant portion of the extracellular matrix. The objective of the present study was to evaluate whether the serum concentrations of laminin and type-IV collagen may serve as biomarkers for cutaneous melanoma. Sixty pathologically confirmed melanoma patients were enrolled in the study. Serum laminin and type-IV collagen levels were assessed using an ELISA. Thirty healthy controls were also examined. No significant differences in the baseline serum levels of laminin were identified between melanoma patients and healthy controls (P=0.45). However, the baseline serum levels of type-IV collagen were significantly elevated in melanoma patients compared with those in the control group (P<0.001). Clinical parameters, including patient age, gender, localization of lesion, histopathology, stage of disease, serum lactate dehydrogenase concentrations and responsiveness to chemotherapy were found not to be associated with the serum levels of laminin and type-IV collagen (P>0.05). Furthermore, the serum levels of laminin and type-IV collagen had no prognostic value regarding the outcome for melanoma patients (P=0.36 and P=0.26, respectively). While laminin levels showed no diagnostic value, the serum concentrations of type-IV collagen were indicated to serve as a diagnostic marker in patients with cutaneous melanoma. In conclusion, type-IV collagen levels may be used as a diagnostic marker for cutaneous melanoma, while being void of any prognostic value. PMID:27330797

  17. Type IV collagen is a tumour stroma-derived biomarker for pancreas cancer

    PubMed Central

    Öhlund, D; Lundin, C; Ardnor, B; Öman, M; Naredi, P; Sund, M

    2009-01-01

    Background: Pancreas cancer is a dreaded disease with high mortality, despite progress in surgical and oncological treatments in recent years. The field is hampered by a lack of good prognostic and predictive tumour biomarkers to be used during follow-up of patients. Methods: The circulating level of type IV collagen was measured by ELISA in pancreas cancer patients and controls. The expression pattern of type IV collagen in normal pancreas, pancreas cancer tissue and in pancreas cancer cell lines was studied by immunofluorescence and Western blot techniques. Results: Patients with pancreas cancer have significantly increased circulating levels of type IV collagen. In pancreas cancer tissue high levels of type IV collagen expression was found in close proximity to cancer cells in the tumour stroma. Furthermore, pancreas cancer cells were found to produce and secrete type IV collagen in vitro, which in part can explain the high type IV collagen expression observed in pancreas cancer tissue, and the increased circulating levels in pancreas cancer patients. Of clinical importance, our results show that the circulating level of type IV collagen after surgery is strongly related to prognosis in patients treated for pancreas cancer by pancreatico-duodenectomy with curative intent. Persisting high levels of circulating type IV collagen after surgery indicates a quick relapse in disease and poor survival. Conclusion: Our results most importantly show that stroma related substances can be evaluated as potential cancer biomarkers, and thereby underline the importance of the tumour microenvironment also in this context. PMID:19491897

  18. Non-existence of perfect dark energy fluid in Bianchi type-IV space time

    NASA Astrophysics Data System (ADS)

    Mishra, B.; Sahoo, P. K.; Suresh, Srikanth

    2015-07-01

    In this paper, non-diagonal Bianchi type-IV space-time is investigated in Einstein general theory of relativity. The matter field is considered in the form of perfect dark energy fluid. It is interesting to observe that in this case, Bianchi type IV perfect dark energy fluid cosmological model does not exist. The space-time reduces to Minkowskian geometry.

  19. Middle ear mechanics of type IV and type V tympanoplasty: II. Clinical analysis and surgical implications.

    PubMed

    Merchant, S N; Rosowski, J J; Ravicz, M E

    1995-09-01

    Type IV and type V tympanoplasty operations are simple, robust, and well-established techniques to reconstruct middle ears that have been severely altered by chronic otitis media. In a previous paper, the authors developed a simple four-block physiologic model to describe hearing results after these procedures. This paper presents a comparison of model predictions to hearing results obtained from a detailed retrospective clinical review of 30 type IV and type V procedures. Audiograms predicted by the model and those observed clinically show good agreement over a wide frequency range (500-4000 Hz) and for many different clinical conditions. Thus, this model reliably predicts postsurgical hearing results. The application of quantitative analyses provided by this model permits the formation of a few simple surgical rules that may improve postoperative hearing results. (1) The footplate should be left as mobile as possible (e.g., by covering it with a very thin split-thickness skin graft, as opposed to a fascia graft, which will tend to stiffen it). If the footplate is ankylosed, it should be removed and replaced with a compliant tissue graft, such as fat. (2) The round window acoustic graft shield should be made as stiff as possible. If the shield material used is temporalis fascia, then one should consider using more than one layer, or reinforcing it with cartilage. (3) An attempt should be made to create an aerated cavum minor containing at least 0.03 cc of air. PMID:8588661

  20. 10 CFR Appendix IV to Part 960 - Types of Information for the Nomination of Sites as Suitable for Characterization

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Types of Information for the Nomination of Sites as Suitable for Characterization IV Appendix IV to Part 960 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Pt. 960, App. IV Appendix IV to Part 960—Types of Information for...

  1. Type IV collagen is a novel DEJ biomarker that is reduced by radiotherapy.

    PubMed

    McGuire, J D; Gorski, J P; Dusevich, V; Wang, Y; Walker, M P

    2014-10-01

    The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy--teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ

  2. Metachronous Bilateral Posterior Tibial Artery Aneurysms in Ehlers-Danlos Syndrome Type IV

    SciTech Connect

    Hagspiel, Klaus D.; Bonatti, Hugo; Sabri, Saher; Arslan, Bulent; Harthun, Nancy L.

    2011-04-15

    Ehlers-Danlos syndrome type IV is a life-threatening genetic connective tissue disorder. We report a 24-year-old woman with EDS-IV who presented with metachronous bilateral aneurysms/pseudoaneurysms of the posterior tibial arteries 15 months apart. Both were treated successfully with transarterial coil embolization from a distal posterior tibial approach.

  3. UNIFICATION OF LUMINOUS TYPE 1 QUASARS THROUGH C IV EMISSION

    SciTech Connect

    Richards, Gordon T.; Kruczek, Nicholas E.; Deo, Rajesh P.; Kratzer, Rachael M.; Gallagher, S. C.; Hall, Patrick B.; Hewett, Paul C.; Leighly, Karen M.; Shen, Yue

    2011-05-15

    Using a sample of {approx}30,000 quasars from the 7th Data Release of the Sloan Digital Sky Survey, we explore the range of properties exhibited by high-ionization, broad emission lines, such as C IV {lambda}1549. Specifically, we investigate the anti-correlation between continuum luminosity and emission-line equivalent width (the Baldwin Effect (BEff)) and the 'blueshifting' of the high-ionization emission lines with respect to low-ionization emission lines. Employing improved redshift determinations from Hewett and Wild, the blueshift of the C IV emission line is found to be nearly ubiquitous, with a mean shift of {approx}810 km s{sup -1} for radio-quiet (RQ) quasars and {approx}360 km s{sup -1} for radio-loud (RL) quasars. The BEff is present in both RQ and RL samples. We consider these phenomena within the context of an accretion disk-wind model that is modulated by the nonlinear correlation between ultraviolet and X-ray continuum luminosity. Composite spectra are constructed as a function of C IV emission-line properties in an attempt to reveal empirical relationships between different line species and the continuum. Within a two-component disk+wind model of the broad emission-line region (BELR), where the wind filters the continuum seen by the disk component, we find that RL quasars are consistent with being dominated by the disk component, while broad absorption line quasars are consistent with being dominated by the wind component. Some RQ objects have emission-line features similar to RL quasars; they may simply have insufficient black hole (BH) spin to form radio jets. Our results suggest that there could be significant systematic errors in the determination of L{sub bol} and BH mass that make it difficult to place these findings in a more physical context. However, it is possible to classify quasars in a paradigm where the diversity of BELR parameters is due to differences in an accretion disk wind between quasars (and over time); these differences are

  4. Type IV congenital laryngeal web: Case report and 15 year follow up.

    PubMed

    Sorichetti, Brendan; Moxham, John P; Kozak, Frederick K

    2016-01-01

    A five day old patient with mild VACTERL syndrome had repair of a type IV congenital laryngeal web with successful decannulation 76 days later. Voice and respiratory outcome is good with follow up 15 years later. This case presents a rare clinical finding of a type IV laryngeal web successfully repaired with a keel and subsequent long term follow up during an era when it was suggested that repair be delayed until 18 months of age at the earliest. PMID:26954872

  5. Laparoscopic treatment of type III and IV hiatal hernia – authors’ experience

    PubMed Central

    Grzesiak-Kuik, Agata; Pędziwiatr, Michał; Budzyński, Andrzej

    2014-01-01

    Introduction There are four types of hiatal hernias, and diagnosis is established on the basis of gastroscopy in the majority of cases. Type III represents a mixed type in which the abdominal esophagus as well as the gastric cardia and fundus protrude into the thorax through the pathologically widened esophageal hiatus. Type IV, the so-called upside down stomach, can be considered an evolutionary form of type III, and refers to herniation of nearly the whole stomach (except for the cardia and pylorus) into the thorax. Types III and IV of hiatal hernias represent a group of rare diaphragmatic defects; thus, most centers do not possess considerable experience in their treatment. Frequently, laparoscopic treatment is implemented, although, according to some authors, conversion to laparotomy, thoracotomy, or thoracolaparotomy is necessary in selected cases. Aim To analyze the outcomes of laparoscopic treatment of the largest hiatal hernias, i.e. type III and IV hernias. Material and methods A total of 25 patients diagnosed with type III and IV hiatal hernia were included in further analysis. Results As many as 19 out of 25 patients (76%) assessed the outcome of the surgery as evidently positive and reported marked improvement in the quality of life. Conclusions The laparoscopic technique constitutes an excellent and safe method of repair of even the most complex defects in the esophageal hiatus. Therefore, the minimally invasive technique combined with an anti-reflux procedure should be the method of choice in patients with type III and IV hernia. PMID:25097681

  6. Complete primary structure of the triple-helical region and the carboxyl-terminal domain of a new type IV collagen chain, alpha 5(IV).

    PubMed

    Pihlajaniemi, T; Pohjolainen, E R; Myers, J C

    1990-08-15

    We have isolated and characterized overlapping cDNA clones which code for a previously unidentified human collagen chain. Although the cDNA-derived primary structure of this new polypeptide is very similar to the basement membrane collagen alpha 1(IV) and alpha 2(IV) chains, the carboxyl-terminal collagenous/non-collagenous junction sequence does not correspond to the junction sequence in either of the newly described alpha 3(IV) or alpha 4(IV) chains (Butkowski, R.J., Langeveld, J.P.M., Wieslander, J., Hamilton, J., and Hudson, B. G. (1987) J. Biol. Chem. 262, 7874-7877). Thus the protein presented here has been designated the alpha 5 chain of type IV collagen. Four clones encode an open reading frame of 1602 amino acids that cover about 95% of the entire chain including half of the amino-terminal 7S domain and all of the central triple-helical region and carboxyl-terminal NC1 domain. The collagenous region of the alpha 5(IV) chain contains 22 interruptions which are in most cases identical in distribution to those in both the alpha 1(IV) and alpha 2(IV) chains. Despite the relatively low degree of conservation among the amino acids in the triple-helical region of the three type IV collagen chains, analysis of the sequences clearly showed that alpha 5(IV) is more related to alpha 1(IV) than to alpha 2(IV). This similarity between the alpha 5(IV) and alpha 1(IV) chains is particularly evident in the NC1 domains where the two polypeptides are 83% identical in contrast to the alpha 5(IV) and alpha 2(IV) identity of 63%. In addition to greatly increasing the complexity of basement membranes, the alpha 5 chain of type IV collagen may be responsible for specialized functions of some of these extracellular matrices. In this regard, it is important to note that we have recently assigned the alpha 5(IV) gene to the region of the X chromosome containing the locus for a familial type of hereditary nephritis known as Alport syndrome (Myers, J.C., Jones, T.A., Pohjalainen, E

  7. Anomalous resistivity at the field null of the FRC: a quasi-linear expression based upon flute-type modes

    SciTech Connect

    Gerwin, R.

    1983-10-01

    In the Field-Reversed Theta Pinch (FRC) experiment, the poloidal flux is observed to be lost at a rate several times greater than classical resistivity would allow. Thus, there must be anomalous resistivity at the field null. Assuming that an electromagnetic microinstability of the flute mode type is responsible for this, we derived a general expression for the anomalous resistivity at the field null based upon a quasi-linear model of the microturbulence. This general expression does not depend upon the details of the ion-species model, for example, whether the ions are fluid or kinetic.

  8. Rat 17 beta-hydroxysteroid dehydrogenase type IV is a novel peroxisome proliferator-inducible gene.

    PubMed

    Corton, J C; Bocos, C; Moreno, E S; Merritt, A; Marsman, D S; Sausen, P J; Cattley, R C; Gustafsson, J A

    1996-11-01

    To better understand the molecular mechanisms of the pleiotropic responses induced by exposure to peroxisome proliferator chemicals (PPCs), we conducted a systematic search for genes whose mRNA levels are modulated by the PPC WY-14,643 (WY) in rat liver. The sequence of one up-regulated cDNA (2480 bp) was predicted to encode a protein of 735 aa with 82% identity to the porcine 17 beta-hydroxysteroid dehydrogenase type IV (HSD IV). Like the porcine enzyme, the rat HSD IV contains' a region homologous to yeast hydratase-dehydrogenase-epimerases and to sterol carrier proteins, indicating that the rat HSD IV has broad substrate specificity and contributes to cholesterol metabolism. The rat HSD IV was regulated by diverse PPCs via two distinct mechanisms. Induction of HSD IV and acyl-CoA oxidase (ACO) proteins in rat liver at different treatment times and concentrations of gemfibrozil and di-n-butyl phthalate were almost identical, indicating that HSD IV mRNA induction involves the peroxisome proliferator-activated receptor alpha, a regulator of ACO. In contrast, HSD IV protein levels were only weakly induced by WY, a strong inducer of ACO protein, even though the levels of HSD IV and ACO mRNA were strongly stimulated by WY and gemfibrozil. Thus, HSD IV protein levels were uniquely regulated pretranslationally by WY via a novel mechanism. Increased conversion of estradiol to the less-active estrone by HSD IV induction may explain how phthalate exposure leads to decreases in serum estradiol levels and suppression of ovulation. PMID:8913347

  9. Limited significance of curative surgery in Borrmann type IV gastric cancer.

    PubMed

    Kim, Eun Young; Yoo, Han Mo; Song, Kyo Young; Park, Cho Hyun

    2016-07-01

    Borrmann type IV advanced gastric cancer has a poor prognosis. Although surgical resection remains the only hope for a cure, the role of curative surgery is questionable in this type of cancer. This study defined the role of curative surgery in the prognosis of type IV gastric cancer. We analyzed 168 patients with Borrmann type IV undergoing surgery at Seoul St. Mary's Hospital from 1989 to 2010. We categorized the patients into curative (R0) and non-curative (R1, R2, and non-resection) groups. The curative and non-curative groups comprised 88 and 80 patients, respectively. The preoperative predictive value of Borrmann type IV was 50.5, and 8.9 % of the patients had microscopic resection margin involvement. The 3- to 5-year overall survival (OS) of patients in the curative group was significantly higher than that of in the non-curative group (p < 0.001). However, in a multivariate analysis, curability was not a significant predictor of survival (p = 0.187). In the curative group, the most frequent recurrence site was the peritoneum (85.7 %). Most recurrences occurred within 2 years. The role of surgery for Borrmann type IV is quite limited. Such cases have a poor prognosis even after curative surgery. In addition, microscopic resection margin involvement is frequent in type IV cancer because it is difficult to diagnose preoperatively. Therefore, multimodal diagnostic tools and treatment strategies should be developed for Borrmann type IV gastric cancer. PMID:27251378

  10. Avoiding type III, IV, and V errors through collaborative research.

    PubMed

    Yamatani, Hide; Mann, Aaron; Feit, Marvin

    2013-01-01

    Major types of empirical errors reviewed by a number of leading research textbooks include discussions of Type I and Type II errors. However, applied human service researchers can commit other types of errors that should be avoided. The potential benefits of the applied, collaborative research (in contrast to traditional participatory research) include an assurance that the study begins with the "right" questions that are important for community residents. Such research practice also helps generate useful research findings for decisions regarding redistribution of resources and resolving community issues. The aim of collaborative research is not merely to advance scientific understanding, but also to produce empirical findings that are usable for addressing priority needs and problems of distressed communities. A review of a case example (Garfield Community Assessment Study) illustrates the principles and practices of collaborative research. PMID:23879359

  11. Complete primary structure of the sixth chain of human basement membrane collagen, alpha 6(IV). Isolation of the cDNAs for alpha 6(IV) and comparison with five other type IV collagen chains.

    PubMed

    Zhou, J; Ding, M; Zhao, Z; Reeders, S T

    1994-05-01

    Basement membranes were previously believed to contain five distinct type IV collagen subunits. We have recently isolated part of the cDNA for a novel type IV collagen, alpha 6(IV), and shown that COL4A6, the gene encoding this new chain, is deleted in Alport syndrome-associated leiomyomatosis (Zhou, J., Mochizuki, T., Smeets, H., Antignac, C., Laurila, P., de Paepe, A., Tryggvason, K., and Reeders, S. T. (1993) Science 261, 1167-1169). Here, we describe the entire human alpha 6(IV) cDNA and show that the gene encodes a classical type IV collagen with homology throughout its length to all the other five chains. There is a 21-residue signal peptide, a 1417-residue collagenous domain interrupted at 25 points, and a 228-residue carboxyl-terminal non-collagenous domain. When the complete primary structure of this new chain was compared with all the other known chains, it became clear that alpha 6(IV) has the most resemblance to alpha 2(IV) and alpha 4(IV). The evolution of the six chains was deduced, allowing a new classification of the type IV collagen family. The alpha 6(IV) chain is a candidate gene for X-linked Alport syndrome; knowledge of the complete structure of the chain will permit us to screen systematically for mutations in patients and to generate recombinant proteins and synthetic peptides for further study of cell-matrix interactions involving the alpha 6(IV) chain. PMID:8175748

  12. Type IV Ehlers-Danlos Syndrome: A Surgical Emergency? A Case of Massive Retroperitoneal Hemorrhage.

    PubMed

    Chun, Stephen G; Pedro, Patrick; Yu, Mihae; Takanishi, Danny M

    2011-01-01

    Retroperitoneal hemorrhagic bleeding is a known manifestation of Type-IV Ehlers-Danlos Syndrome that is caused by loss-of-function mutations of the pro-alpha-1 chains of type III pro-collagen (COL3A1) resulting in vascular fragility. A number of previous reports describe futile surgical intervention for retroperitoneal bleeding in Type-IV Ehlers-Danlos Syndrome with high post-operative mortality, although the rarity of retroperitoneal bleeding associated with Type-IV Ehlers-Danlos Syndrome precludes an evidence-based approach to clinical management. We report a 23-year-old male with history of Type-IV Ehlers-Danlos Syndrome who presented with severe abdominal pain and tachycardia following an episode of vomiting. Further work-up of his abdominal pain revealed massive retroperitoneal bleeding by CT-scan of the abdomen. Given numerous cases of catastrophic injury caused by surgical intervention in Type-IV Ehlers-Danlos Syndrome, the patient was treated non-operatively, and the patient made a full recovery. This case suggests that even in cases of large retroperitoneal hemorrhages associated with Ehlers-Danlos Syndrome, it may not truly represent a surgical emergency. PMID:21966332

  13. Endovascular repair of direct carotid-cavernous fistula in Ehlers-Danlos type IV.

    PubMed

    Linfante, Italo; Lin, Eugene; Knott, Eric; Katzen, Barry; Dabus, Guilherme

    2014-01-01

    Ehlers-Danlos syndrome (EDS) type IV is a collagen vascular disease with an autosomal dominant inheritance caused by COL3A1 mutation. Patients with EDS type IV can present with organ rupture, spontaneous arterial dissections and ruptured aneurysms. Because of their propensity to form arterial dissections, aneurysms and rupture, they can develop carotid-cavernous fistula (CCF) after minor trauma or spontaneously. In EDS, it has been reported that even conventional catheter diagnostic angiography may result in large artery dissections and vessel rupture. In addition, the treatment of CCF in EDS type IV can result in up to 59% mortality after initial treatment, of which 23% is attributed to direct complications of treatment. We present the case of a patient with EDS type IV who previously had spontaneous dissection and multiple pseudoaneurysms of both the iliac and femoral arteries and the distal abdominal aorta. Several years later the patient developed a direct type A CCF which was successfully treated with endovascular embolization using a transvenous approach with detachable coils. The literature pertaining to CCF in EDS type IV and its treatment is reviewed. PMID:24385391

  14. Endovascular repair of direct carotid-cavernous fistula in Ehlers-Danlos type IV.

    PubMed

    Linfante, Italo; Lin, Eugene; Knott, Eric; Katzen, Barry; Dabus, Guilherme

    2015-01-01

    Ehlers-Danlos syndrome (EDS) type IV is a collagen vascular disease with an autosomal dominant inheritance caused by COL3A1 mutation. Patients with EDS type IV can present with organ rupture, spontaneous arterial dissections and ruptured aneurysms. Because of their propensity to form arterial dissections, aneurysms and rupture, they can develop carotid-cavernous fistula (CCF) after minor trauma or spontaneously. In EDS, it has been reported that even conventional catheter diagnostic angiography may result in large artery dissections and vessel rupture. In addition, the treatment of CCF in EDS type IV can result in up to 59% mortality after initial treatment, of which 23% is attributed to direct complications of treatment. We present the case of a patient with EDS type IV who previously had spontaneous dissection and multiple pseudoaneurysms of both the iliac and femoral arteries and the distal abdominal aorta. Several years later the patient developed a direct type A CCF which was successfully treated with endovascular embolization using a transvenous approach with detachable coils. The literature pertaining to CCF in EDS type IV and its treatment is reviewed. PMID:24401479

  15. On the Directivity of Low-Frequency Type IV Radio Bursts

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.; Akiyama, S.; Makela, P.; Yashiro, S.; Cairns, I. H.

    2016-01-01

    An intense type IV radio burst was observed by the STEREO Behind (STB) spacecraft located about 144 deg. behind Earth. The burst was associated with a large solar eruption that occurred on the backside of the Sun (N05E151) close to the disk center in the STB view. The eruption was also observed by the STEREO Ahead (STA) spacecraft (located at 149 deg. ahead of Earth) as an eruption close to the west limb (N05W60) in that view. The type IV burst was complete in STB observations in that the envelope reached the lowest frequency and then receded to higher frequencies. The burst was partial viewed from STA, revealing only the edge coming down to the lowest frequency. The type IV burst was not observed at all near Earth because the source was 61 deg. behind the east limb. The eruption was associated with a low-frequency type II burst observed in all three views, although it was not very intense. Solar energetic particles were also observed at both STEREOs and at SOHO, suggesting that the shock was much extended, consistent with the very high speed of the CME (2048 km/s). These observations suggest that the type IV emission is directed along a narrow cone above the flare site. We confirm this result statistically using the type IV bursts of solar cycle 23.

  16. Endovascular repair of direct carotid–cavernous fistula in Ehlers–Danlos type IV

    PubMed Central

    Linfante, Italo; Lin, Eugene; Knott, Eric; Katzen, Barry; Dabus, Guilherme

    2014-01-01

    Ehlers–Danlos syndrome (EDS) type IV is a collagen vascular disease with an autosomal dominant inheritance caused by COL3A1 mutation. Patients with EDS type IV can present with organ rupture, spontaneous arterial dissections and ruptured aneurysms. Because of their propensity to form arterial dissections, aneurysms and rupture, they can develop carotid–cavernous fistula (CCF) after minor trauma or spontaneously. In EDS, it has been reported that even conventional catheter diagnostic angiography may result in large artery dissections and vessel rupture. In addition, the treatment of CCF in EDS type IV can result in up to 59% mortality after initial treatment, of which 23% is attributed to direct complications of treatment. We present the case of a patient with EDS type IV who previously had spontaneous dissection and multiple pseudoaneurysms of both the iliac and femoral arteries and the distal abdominal aorta. Several years later the patient developed a direct type A CCF which was successfully treated with endovascular embolization using a transvenous approach with detachable coils. The literature pertaining to CCF in EDS type IV and its treatment is reviewed. PMID:24385391

  17. Type IV collagen-initiated signals provide survival and growth cues required for liver metastasis.

    PubMed

    Burnier, J V; Wang, N; Michel, R P; Hassanain, M; Li, S; Lu, Y; Metrakos, P; Antecka, E; Burnier, M N; Ponton, A; Gallinger, S; Brodt, P

    2011-09-01

    The liver is a major site of metastasis for human malignancies, yet the factors that regulate tumor cell survival and growth in this organ remain elusive. Previously, we reported that M-27(IGF-IR) murine lung carcinoma cells with ectopic insulin-like growth factor-1 (IGF-I) receptor overexpression acquired a site-specific, liver-metastasizing potential. Gene expression profiling and subsequent RNA and protein analyses revealed that this was associated with major changes to the expression of extracellular matrix (ECM) protein-encoding genes including type III, IV and XVIII collagen genes, and these changes were also observed in the respective tumors in vivo. Because type IV collagen was the most prominently altered ECM protein in this model, we further analyzed its functional relevance to liver metastasis. M-27 cells stably overexpressing type IV collagen α1 and α2 chains were generated and their growth and metastatic properties investigated. We found that these cells acquired a site-selective growth advantage in the liver and this was associated with cell rescue from anoikis in a collagen IV/α2 integrin/FAK-dependent manner and increased responsiveness to IGF-I. Conversely, collagen IV or focal adhesion kinase (FAK) silencing by small-interfering RNA in highly metastatic tumor cells enhanced anoikis and decreased liver metastases formation. Moreover, analysis of human surgical specimens revealed uniformly high collagen IV expression in 65/65 hepatic metastases analyzed, regardless of tissue of origin, whereas it was variable and generally low in 50/50 primary colorectal carcinoma specimens examined. The results suggest that collagen IV-conveyed signals are essential cues for liver metastasis in diverse tumor types and identify mediators of collagen IV signaling as potential therapeutic targets in the management of hepatic metastases. PMID:21478904

  18. Binding of human plasminogen to basement-membrane (type IV) collagen.

    PubMed

    Stack, M S; Moser, T L; Pizzo, S V

    1992-05-15

    Plasminogen, the zymogen form of the serine proteinase plasmin, has been implicated in numerous physiological and pathological processes involving extracellular-matrix remodelling. We have previously demonstrated that the activation of plasminogen catalysed by tissue plasminogen activator is dramatically stimulated in the presence of basement-membrane-specific type IV collagen [Stack, Gonzalez-Gronow & Pizzo (1990) Biochemistry 29, 4966-4970]. The present paper describes the binding of plasminogen to type IV collagen. Plasminogen binds to both the alpha 1(IV) and alpha 2(IV) chains of basement-membrane collagen, with binding to the alpha 2(IV) chain preferentially inhibited by 6-aminohexanoic acid. This binding is specific and saturable, with Kd,app. values of 11.5 and 12.7 nM for collagen and gelatin respectively. Although collagen also binds to immobilized plasminogen, this interaction is unaffected by 6-aminohexanoic acid. Limited elastase proteolysis of plasminogen generated distinct collagen-binding fragments, which were identified as the kringle 1-3 and kringle 4 domains. No binding of collagen to mini-plasminogen was observed. These studies demonstrate a specific interaction between plasminogen and type IV collagen and provide further evidence for regulation of plasminogen activation by protein components of the extracellular matrix. PMID:1599390

  19. Perisigmoid Abscess Leading to a Diagnosis of Ehlers-Danlos Syndrome Type IV

    PubMed Central

    Kesavan, Anil; Srikumar, Pillai B.; McConnie, Randolph M.

    2016-01-01

    The Ehlers-Danlos syndromes (EDS) are a group of connective tissue disorders characterized by triad of joint hypermobility, skin extensibility, and tissue fragility. Ehlers-Danlos syndrome type IV places patients at risk for life-threatening, spontaneous, vascular or visceral rupture due to reduced or abnormal secretion of type III collagen. We present an adolescent male who was found to have a perisigmoid abscess with a fistula connecting to adjacent sigmoid colon secondary to undiagnosed EDS type IV. Conservative management with antibiotics and bowel rest was pursued to allow for elective resection for his acute complicated diverticulitis at a safer time. PMID:26958560

  20. Perisigmoid Abscess Leading to a Diagnosis of Ehlers-Danlos Syndrome Type IV.

    PubMed

    Normatov, Inessa; Kesavan, Anil; Srikumar, Pillai B; McConnie, Randolph M

    2016-01-01

    The Ehlers-Danlos syndromes (EDS) are a group of connective tissue disorders characterized by triad of joint hypermobility, skin extensibility, and tissue fragility. Ehlers-Danlos syndrome type IV places patients at risk for life-threatening, spontaneous, vascular or visceral rupture due to reduced or abnormal secretion of type III collagen. We present an adolescent male who was found to have a perisigmoid abscess with a fistula connecting to adjacent sigmoid colon secondary to undiagnosed EDS type IV. Conservative management with antibiotics and bowel rest was pursued to allow for elective resection for his acute complicated diverticulitis at a safer time. PMID:26958560

  1. Type IV Cracking Susceptibility in Weld Joints of Different Grades of Cr-Mo Ferritic Steel

    NASA Astrophysics Data System (ADS)

    Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Bhanu Sankara Rao, K.

    2009-02-01

    Relative type-IV cracking susceptibility in 2.25Cr-1Mo, 9Cr-1Mo, and 9Cr-1MoVNb ferritic steel weld joint has been assessed. The type-IV cracking was manifested as preferential accumulation of creep deformation and cavitation in the relatively soft intercritical region of heat affected zone of the weld joint. The type-IV cracking susceptibility has been defined as the reduction in creep-rupture strength of weld joint compared to its base metal. The 2.25Cr-1Mo steel exhibited more susceptibility to type-IV cracking at relatively lower temperatures; whereas, at higher temperatures, 9Cr-1MoVNb steel was more susceptible. The relative susceptibility to type-IV cracking in the weld joint of the Cr-Mo steels has been rationalized on the basis of creep-strengthening mechanisms operating in the steels and their venerability to change on intercritical heating during weld thermal cycle, subsequent postweld heat treatment, and creep exposure.

  2. High resolution observations with Artemis-IV and the NRH. I. Type IV associated narrow-band bursts

    NASA Astrophysics Data System (ADS)

    Bouratzis, C.; Hillaris, A.; Alissandrakis, C. E.; Preka-Papadema, P.; Moussas, X.; Caroubalos, C.; Tsitsipis, P.; Kontogeorgos, A.

    2016-02-01

    Context. Narrow-band bursts appear on dynamic spectra from microwave to decametric frequencies as fine structures with very small duration and bandwidth. They are believed to be manifestations of small scale energy release through magnetic reconnection. Aims: We analyzed 27 metric type IV events with embedded narrow-band bursts, which were observed by the ARTEMIS-IV radio spectrograph from 30 June 1999 to 1 August 2010. We examined the morphological characteristics of isolated narrow-band structures (mostly spikes) and groups or chains of structures. Methods: The events were recorded with the SAO high resolution (10 ms cadence) receiver of ARTEMIS-IV in the 270-450 MHz range. We measured the duration, spectral width, and frequency drift of ~12 000 individual narrow-band bursts, groups, and chains. Spike sources were imaged with the Nançay radioheliograph (NRH) for the event of 21 April 2003. Results: The mean duration of individual bursts at fixed frequency was ~100 ms, while the instantaneous relative bandwidth was ~2%. Some bursts had measurable frequency drift, either positive or negative. Quite often spikes appeared in chains, which were closely spaced in time (column chains) or in frequency (row chains). Column chains had frequency drifts similar to type-IIId bursts, while most of the row chains exhibited negative frequently drifts with a rate close to that of fiber bursts. From the analysis of NRH data, we found that spikes were superimposed on a larger, slowly varying, background component. They were polarized in the same sense as the background source, with a slightly higher degree of polarization of ~65%, and their size was about 60% of their size in total intensity. Conclusions: The duration and bandwidth distributions did not show any clear separation in groups. Some chains tended to assume the form of zebra, lace stripes, fiber bursts, or bursts of the type-III family, suggesting that such bursts might be resolved in spikes when viewed with high

  3. Mutations in Type I and Type IV Pilus Biosynthetic Genes Affect Twitching Motility Rates in Xylella fastidiosa▿ †

    PubMed Central

    De La Fuente, Leonardo; Burr, Thomas J.; Hoch, Harvey C.

    2007-01-01

    Xylella fastidiosa possesses both type I and type IV pili at the same cell pole. By use of a microfluidic device, the speed of twitching movement by wild-type cells on a glass surface against the flow direction of media was measured as 0.86 (standard error [SE], 0.04) μm min−1. A type I pilus mutant (fimA) moved six times faster (4.85 [SE, 0.27] μm min−1) and a pilY1 mutant moved three times slower (0.28 [SE, 0.03] μm min−1) than wild-type cells. Type I pili slow the rate of movement, while the putative type IV pilus protein PilY1 is likely important for attachment to surfaces. PMID:17693510

  4. Success and failure rates of cylinder implants in type IV bone.

    PubMed

    Fugazzotto, P A; Wheeler, S L; Lindsay, J A

    1993-11-01

    It is well documented that implant success rates are much lower in Type IV bone than in Types I, II, and III. However, all of these studies have reported on the use of screw type implants. The present study demonstrates the efficacy of cylinder implant use in Type IV bone. A total of 513 cylinders were placed in Type IV bone and were followed for 0 to 60+ months in function. The absolute success rate was 95.7%. Of the 22 fixture failures encountered, 8 were discovered at the time of second stage surgery, 3 during the first year following uncovering, and 11 occurred after 24 to 36 months in function. A possible rationale for the higher success rate of cylinders as compared to that reported for screw type implants in Type IV bone is presented. Further well-controlled studies directly comparing various implant designs in a range of bony sites are needed to better understand and to fully document the differences suggested by the present study. PMID:8295096

  5. Clinical Application of Antenatal Genetic Diagnosis of Osteogenesis Imperfecta Type IV

    PubMed Central

    Yuan, Jing; Li, Song; Xu, YeYe; Cong, Lin

    2015-01-01

    Background Clinical analysis and genetic testing of a family with osteogenesis imperfecta type IV were conducted, aiming to discuss antenatal genetic diagnosis of osteogenesis imperfecta type IV. Material/Methods Preliminary genotyping was performed based on clinical characteristics of the family members and then high-throughput sequencing was applied to rapidly and accurately detect the changes in candidate genes. Results Genetic testing of the III5 fetus and other family members revealed missense mutation in c.2746G>A, pGly916Arg in COL1A2 gene coding region and missense and synonymous mutation in COL1A1 gene coding region. Conclusions Application of antenatal genetic diagnosis provides fast and accurate genetic counseling and eugenics suggestions for patients with osteogenesis imperfecta type IV and their families. PMID:25835785

  6. Exceptionally widespread nanomachines composed of type IV pilins: the prokaryotic Swiss Army knives

    PubMed Central

    Berry, Jamie-Lee; Pelicic, Vladimir

    2014-01-01

    Prokaryotes have engineered sophisticated surface nanomachines that have allowed them to colonize Earth and thrive even in extreme environments. Filamentous machineries composed of type IV pilins, which are associated with an amazing array of properties ranging from motility to electric conductance, are arguably the most widespread since distinctive proteins dedicated to their biogenesis are found in most known species of prokaryotes. Several decades of investigations, starting with type IV pili and then a variety of related systems both in bacteria and archaea, have outlined common molecular and structural bases for these nanomachines. Using type IV pili as a paradigm, we will highlight in this review common aspects and key biological differences of this group of filamentous structures. PMID:25793962

  7. Conservative management of small bowel perforation in Ehlers-Danlos syndrome type IV.

    PubMed

    Allaparthi, Satya; Verma, Himanshu; Burns, David L; Joyce, Ann M

    2013-08-16

    Ehlers-Danlos syndrome (EDS) is a group of inherited connective tissue disorders caused by collagen synthesis defects. EDS type IV, or vascular EDS, is caused by loss-of-function mutations in the type III pro-collagen gene (COL3A1). Common complications of EDS type IV include gastrointestinal bleeding and bowel perforations, posing diagnostic and therapeutic dilemmas for both surgeons and gastroenterologists. Here, we describe a complicated case of EDS type IV in a 35-year-old caucasian female who presented with overt gastrointestinal bleeding. The patient had a prior history of spontaneous colonic perforation, and an uncomplicated upper endoscopy was performed. A careful ileoscopy was terminated early due to tachycardia and severe abdominal pain, and a subsequent computed tomography scan confirmed the diagnosis of ileal perforation. The patient was managed conservatively, and demonstrated daily improvement. At the time of hospital discharge, no further episodes of gastrointestinal blood loss had occurred. This case highlights the benefit of conservative management for EDS patients with gastrointestinal hemorrhage. It is recommended that surgical treatment should be reserved for patients who fail conservative treatment or in cases of hemodynamic instability. Finally, this case demonstrates the necessity for a higher threshold of operative or endoscopic interventions in EDS type IV patients. PMID:23951395

  8. Management of spontaneous colonic perforation in Ehlers-Danlos syndrome type IV.

    PubMed

    Fuchs, Julie R; Fishman, Steven J

    2004-02-01

    A 14-year-old girl with a family history of fatal colonic rupture, presented with a 2-day history of abdominal pain and signs of peritonitis. At laparotomy, a full-thickness perforation of the sigmoid colon was found, which was exteriorized as a loop colostomy. Subsequently, molecular studies of the patient's cultured fibroblasts found a point mutation in the COL3A1 gene, confirming a diagnosis of Ehlers-Danlos syndrome type IV (EDS-IV). Four and a half years later, a total abdominal colectomy and ileoproctostomy were performed, restoring intestinal continuity. At 5 years follow-up, the patient has had no further complications. Although spontaneous colonic perforation is a well-reported manifestation of EDS-IV, a consensus on the surgical management of this complication in EDS-IV has yet to be determined. Given the high rate of reperforation in EDS-IV when the colon is left in place and the low incidence of reported small bowel and rectal perforations, subtotal colectomy is a reasonable treatment. Primary anastomosis and avoidance of an end-ileostomy was possible in this young patient, with no evidence of anastomotic leakage nor reperforation to date. Lifelong close follow-up should be continued in these patients, because the natural history of this anatomy in EDS-IV is not known. PMID:14966763

  9. Dynamic Reorganization and Enzymatic Remodeling of Type IV Collagen at Cell-Biomaterial Interface.

    PubMed

    Coelho, N M; Llopis-Hernández, V; Salmerón-Sánchez, M; Altankov, G

    2016-01-01

    Vascular basement membrane remodeling involves assembly and degradation of its main constituents, type IV collagen (Col IV) and laminin, which is critical during development, angiogenesis, and tissue repair. Remodeling can also occur at cell-biomaterials interface altering significantly the biocompatibility of implants. Here we describe the fate of adsorbed Col IV in contact with endothelial cells adhering on positively charged NH2 or hydrophobic CH3 substrata, both based on self-assembly monolayers (SAMs) and studied alone or mixed in different proportions. AFM studies revealed distinct pattern of adsorbed Col IV, varying from single molecular deposition on pure NH2 to network-like assembly on mixed SAMs, turning to big globular aggregates on bare CH3. Human umbilical endothelial cells (HUVECs) interact better with Col IV adsorbed as single molecules on NH2 surface and readily rearrange it in fibril-like pattern that coincide with secreted fibronectin fibrils. The cells show flattened morphology and well-developed focal adhesion complexes that are rich on phosphorylated FAK while expressing markedly low pericellular proteolytic activity. Conversely, on hydrophobic CH3 substrata HUVECs showed abrogated spreading and FAK phosphorylation, combined with less reorganization of the aggregated Col IV and significantly increased proteolytic activity. The later involves both MMP-2 and MMP-9, as measured by zymography and FITC-Col IV release. The mixed SAMs support intermediate remodeling activity. Taken together these results show that chemical functionalization combined with Col IV preadsorption provides a tool for guiding the endothelial cells behavior and pericellular proteolytic activity, events that strongly affect the fate of cardiovascular implants. PMID:27567485

  10. Campylobacter fetus subspecies contain conserved type IV secretion systems on multiple genomic islands and plasmids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The features contributing to the differences in pathogenicity of the C. fetus subspecies are unknown. Putative factors involved in pathogenesis are located in genomic islands that encode type IV secretion system (T4SS) and fic-domain (filamentation induced by cyclic AMP) proteins. In the genomes of ...

  11. Multiwavelength Analysis of a Moving Type-IV Radio Burst on 4th March 2012

    NASA Astrophysics Data System (ADS)

    Veluchamy, V.; Chen, Y.; Feng, S.; Du, G.; Song, H.; Kong, X.

    2015-12-01

    We performed a multiwavelength analysis of a moving Type-IV radio burst on 4th march 2012. The Type-IV radio burst is observed between 10:39 - 11:00 UT in the frequency range of 300 - 20 MHz. From the radio heliographic observation, the radio source of the type-IV burst is traced and their sky plane speed is estimated as ~ 370 km/s. A plasmoid structure is ejected during the impulsive phase of the flare, at the same time of the type-IV burst and the structure is clearly observed at SDO/AIA 131 Å channel. From this, we find that the radio source moves with the plasmoid. The high brightness temperature profile in the range of 108 - 109 K and the moderate polarization between -50 - 30 % supports the plasma emission mechanism. Further the differential emission measure (DEM) analysis will be carried out and their results will be presented to provide more evidence of the emission mechanism.

  12. The extracellular matrix of hydra is a porous sheet and contains type IV collagen.

    PubMed

    Shimizu, Hiroshi; Aufschnaiter, Roland; Li, Li; Sarras, Michael P; Borza, Dorin-Bogdan; Abrahamson, Dale R; Sado, Yoshikazu; Zhang, Xiaoming

    2008-01-01

    Hydra, as an early diploblastic metazoan, has a well-defined extracellular matrix (ECM) called mesoglea. It is organized in a tri-laminar pattern with one centrally located interstitial matrix that contains type I collagen and two sub-epithelial zones that resemble a basal lamina containing laminin and possibly type IV collagen. This study used monoclonal antibodies to the three hydra mesoglea components (type I, type IV collagens and laminin) and immunofluorescent staining to visualize hydra mesoglea structure and the relationship between these mesoglea components. In addition, hydra mesoglea was isolated free of cells and studied with immunofluorescence and scanning electron microscopy (SEM). Our results show that type IV collagen co-localizes with laminin in the basal lamina whereas type I collagen forms a grid pattern of fibers in the interstitial matrix. The isolated mesoglea can maintain its structural stability without epithelial cell attachment. Hydra mesoglea is porous with multiple trans-mesoglea pores ranging from 0.5 to 1 microm in diameter and about six pores per 100 microm(2) in density. We think these trans-mesoglea pores provide a structural base for epithelial cells on both sides to form multiple trans-mesoglea cell-cell contacts. Based on these findings, we propose a new model of hydra mesoglea structure. PMID:18602803

  13. The extracellular matrix of hydra is a porous sheet and contains type IV collagen

    PubMed Central

    Shimizu, Hiroshi; Aufschnaiter, Roland; Li, Li; Sarras, Michael P.; Borza, Dorin-Bogdan; Abrahamson, Dale R.; Sado, Yoshikazu; Zhang, Xiaoming

    2008-01-01

    Hydra, as an early diploblastic metazoan, has a well defined extracellular matrix (ECM) called-mesoglea. It is organized in a tri-laminar pattern with one centrally located interstitial matrix that contains type I collagen and two sub-epithelial zones that resemble a basal lamina containing laminin and possibly type IV collagen. This study used monoclonal antibodies to the three hydra mesoglea components (type I, type IV collagens and laminin) and immunofluorescent staining to visualize hydra mesoglea structure and the relationship between these mesoglea components. In addition, hydra mesoglea was isolated free of cells and studied with immunofluorescence and SEM. Our results show that type IV collagen co-localizes with laminin in the basal lamina whereas type I collagen forms a grid pattern of fibers in the interstitial matrix. The isolated-mesoglea can maintain its structural stability without epithelial cell attachment. Hydra mesogleais porous with multiple trans-mesoglea pores ranging from 0.5 to 1 µm in diameter and about 6 pores per 100 µm2 in density. We think these trans-mesoglea pores provide a structural base for epithelial cells on both sides to form multiple trans-mesoglea cell-cell contacts. Based on these findings, we propose a new model of hydra mesoglea structure. PMID:18602803

  14. Secretion and assembly of type IV and VI collagens depend on glycosylation of hydroxylysines.

    PubMed

    Sipilä, Laura; Ruotsalainen, Heli; Sormunen, Raija; Baker, Naomi L; Lamandé, Shireen R; Vapola, Miia; Wang, Chunguang; Sado, Yoshikazu; Aszodi, Attila; Myllylä, Raili

    2007-11-16

    Most lysines in type IV and VI collagens are hydroxylated and glycosylated, but the functions of these unique galactosylhydroxylysyl and glucosylgalactosylhydroxylysyl residues are poorly understood. The formation of glycosylated hydroxylysines is catalyzed by multifunctional lysyl hydroxylase 3 (LH3) in vivo, and we have used LH3-manipulated mice and cells as models to study the function of these carbohydrates. These hydroxylysine-linked carbohydrates were shown recently to be indispensable for the formation of basement membranes (Ruotsalainen, H., Sipilä, L., Vapola, M., Sormunen, R., Salo, A. M., Uitto, L., Mercer, D. K., Robins, S. P., Risteli, M., Aszodi, A., Fässler, R., and Myllylä, R. (2006) J. Cell Sci. 119, 625-635). Analysis of LH3 knock-out embryos and cells in this work indicated that loss of glycosylated hydroxylysines prevents the intracellular tetramerization of type VI collagen and leads to impaired secretion of type IV and VI collagens. Mice lacking the LH activity of LH3 produced slightly underglycosylated type IV and VI collagens with abnormal distribution. The altered distribution and aggregation of type VI collagen led to similar ultrastructural alterations in muscle to those detected in collagen VI knockout and some Ullrich congenital muscular dystrophy patients. Our results provide new information about the function of hydroxylysine-linked carbohydrates of collagens, indicating that they play an important role in the secretion, assembly, and distribution of highly glycosylated collagen types. PMID:17873278

  15. Monoclonal antibodies to human type IV collagen: useful reagents to demonstrate the heterotrimeric nature of the molecule.

    PubMed Central

    Odermatt, B F; Lang, A B; Rüttner, J R; Winterhalter, K H; Trüeb, B

    1984-01-01

    Monoclonal antibodies (mAbs) have been prepared against type IV collagen isolated from human kidney. Two mAbs, designated CIV 22 and CIV 16, were extensively characterized. CIV 22 reacted only with native type IV collagen, whereas CIV 16 also bound to fragments derived from the alpha 1(IV) chain after reduction and alkylation of the molecule. Therefore, CIV 22 recognizes a conformational epitope on the triple helical type IV collagen, whereas CIV 16 binds to a sequential determinant in the carboxyl-terminal half of the alpha 1(IV) chain. By immunofluorescence, typical basement membrane structures were stained with both mAbs on frozen sections of different human organs. The mAbs were used to investigate the chain composition of type IV collagen. Radiolabeled type IV collagen bound to CIV 22, proving its triple helical configuration. These native probes, containing both the alpha 1(IV) and the alpha 2(IV) chains, also bound to CIV 16. Since CIV 16 does not react with the isolated alpha 2(IV) chain, both chains must be arranged in a single triple helical molecule (heterotrimer). Images PMID:6209713

  16. Searching algorithm for type IV secretion system effectors 1.0: a tool for predicting type IV effectors and exploring their genomic context.

    PubMed

    Meyer, Damien F; Noroy, Christophe; Moumène, Amal; Raffaele, Sylvain; Albina, Emmanuel; Vachiéry, Nathalie

    2013-11-01

    Type IV effectors (T4Es) are proteins produced by pathogenic bacteria to manipulate host cell gene expression and processes, divert the cell machinery for their own profit and circumvent the immune responses. T4Es have been characterized for some bacteria but many remain to be discovered. To help biologists identify putative T4Es from the complete genome of α- and γ-proteobacteria, we developed a Perl-based command line bioinformatics tool called S4TE (searching algorithm for type-IV secretion system effectors). The tool predicts and ranks T4E candidates by using a combination of 13 sequence characteristics, including homology to known effectors, homology to eukaryotic domains, presence of subcellular localization signals or secretion signals, etc. S4TE software is modular, and specific motif searches are run independently before ultimate combination of the outputs to generate a score and sort the strongest T4Es candidates. The user keeps the possibility to adjust various searching parameters such as the weight of each module, the selection threshold or the input databases. The algorithm also provides a GC% and local gene density analysis, which strengthen the selection of T4E candidates. S4TE is a unique predicting tool for T4Es, finding its utility upstream from experimental biology. PMID:23945940

  17. Spontaneous rupture of the spleen in type IV Ehlers-Danlos syndrome: report of a case.

    PubMed

    Privitera, Antonio; Milkhu, Chaz; Datta, Vivek; Sayegh, Mazim; Cohen, Richard; Windsor, Alastair

    2009-01-01

    The vascular type of Ehlers-Danlos syndrome, type IV, is associated with severe complications, including arterial rupture and visceral perforation. However, to our knowledge, there has been only one previous report of splenic rupture caused by a spontaneous hemorrhage in type IV Ehlers-Danlos syndrome. We report another case of this uncommon complication, occurring in a 35-year-old woman who presented after the sudden onset of acute abdominal pain. Patients should be stabilized quickly in the intensive care unit and the most timesaving surgical techniques used. Moreover, tissues must be handled with great care intraoperatively in view of their extreme fragility. Despite prompt and appropriate treatment, the prognosis is often dismal. PMID:19132469

  18. Type-IV Superconductivity: Can Superconductivity be more Exotic than Unconventional?

    NASA Astrophysics Data System (ADS)

    Lebed, A. G.

    2006-02-01

    Abrikosov vortex phase in s-wave layered superconductor in a parallel magnetic field is shown to be absolutely unstable with respect to the appearance of a triplet component which breaks inversion (parity) and spin-rotational symmetries of Cooper pairs. Symmetry breaking paramagnetic effects are demonstrated to be of the order of unity if the orbital upper critical field, Hc2 (0), is of the order of Clogston paramagnetic limiting field, Hp. We suggest a generic phase diagram of such type-IV superconductor, which is singlet one at H=0 and in the Meissner phase and characterized by mixed singlet triplet order parameter with broken symmetries of Copper pairs in vortex phase. A possibility to observe type-IV superconductivity in clean organic, high-Tc, and MgB2 superconductors is discussed.

  19. Type IV Sacrococcygeal Teratoma Displacing the Urinary Bladder: Unique Magnetic Resonance Imaging

    PubMed Central

    Eftekharzadeh, Sahar; Keihani, Sorena; Fareghi, Mehdi; Alamsahebpour, Alireza; Kajbafzadeh, Abdol-Mohammad

    2016-01-01

    Type IV sacrococcygeal teratoma is a rare pediatric tumor that is confined to the presacral area with no external component. The signs and symptoms often arise due to mass effect and compression of adjacent organs. Urinary retention is an uncommon presenting symptom in these patients. A wide spectrum of imaging findings may be encountered in cases with sacrococcygeal teratoma because of variability of tumor size and components. We hereby present a unique magnetic resonance urography finding in a type IV sacrococcygeal teratoma which caused bladder displacement. A meticulous and complete resection of tumor with special attention to the pelvic plexus led to preservation of normal voiding function and normal bowel function in this patient. PMID:27413571

  20. Glycogen Storage Disease Type IV: A Case With Histopathologic Findings in First-Trimester Placental Tissue.

    PubMed

    Bendroth-Asmussen, Lisa; Aksglaede, Lise; Gernow, Anne B; Lund, Allan M

    2016-01-01

    A 30-yr-old woman presented with 2 consecutive miscarriages within 7 mo. Histopathologic examination of the placental tissue showed intracytoplasmic inclusion vacuoles with a strong reaction in Periodic acid-Schiff staining and a slightly pallor reaction in alcian blue staining. Additional molecular genetic analyses confirmed glycogen storage disease Type IV with the finding of compound heterozygosity for 2 mutations (c.691+2T>C and c.1570C>T, p.R524X) in the GBE1 gene. We conclude that glycogen storage disease Type IV can cause early miscarriage and that diagnosis can initially be made on histopathologic examination. Genetic analysis is required to confirm the diagnosis and to offer prenatal genetic testing in future pregnancies. PMID:26166723

  1. A numerical study of the unsteady processes associated with the type IV shock interaction

    NASA Technical Reports Server (NTRS)

    Lind, Charles A.; Lewis, Mark J.

    1993-01-01

    A time-dependent ADI formulation of the two dimensional Navier-Stokes equations coupled with the total variation diminishing (TVD) scheme is used to examine the type IV shock interaction time accurately. The experimentally measured and computationally calculated unsteadiness of the type IV interaction is shown to be related to the formation and shedding of shear layers in the shock layer, and the frequency of oscillation of the jet is a strong function of the shedding rate of these shear layers. For one particular geometry, an oscillation frequency of 1.4 kHz was calculated. The effects of shock impingement angle and shock strength on the location and magnitude of the peak pressure are also identified. In one case it is shown that a 1-deg change in the impinging shock angle can alter the location of the associated jet by almost 11 deg with a change in the peak surface pressure of 32 percent.

  2. Irradiation Alters MMP-2/TIMP-2 System and Collagen Type IV Degradation in Brain

    SciTech Connect

    Lee, Won Hee; Warrington, Junie P.; Sonntag, William E.; Lee, Yong Woo

    2012-04-01

    Purpose: Blood-brain barrier (BBB) disruption is one of the major consequences of radiation-induced normal tissue injury in the central nervous system. We examined the effects of whole-brain irradiation on matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs) and extracellular matrix (ECM) degradation in the brain. Methods and Materials: Animals received either whole-brain irradiation (a single dose of 10 Gy {gamma}-rays or a fractionated dose of 40 Gy {gamma}-rays, total) or sham-irradiation and were maintained for 4, 8, and 24 h following irradiation. mRNA expression levels of MMPs and TIMPs in the brain were analyzed by real-time reverse transcriptase-polymerase chain reaction (PCR). The functional activity of MMPs was measured by in situ zymography, and degradation of ECM was visualized by collagen type IV immunofluorescent staining. Results: A significant increase in mRNA expression levels of MMP-2, MMP-9, and TIMP-1 was observed in irradiated brains compared to that in sham-irradiated controls. In situ zymography revealed a strong gelatinolytic activity in the brain 24 h postirradiation, and the enhanced gelatinolytic activity mediated by irradiation was significantly attenuated in the presence of anti-MMP-2 antibody. A significant reduction in collagen type IV immunoreactivity was also detected in the brain at 24 h after irradiation. In contrast, the levels of collagen type IV were not significantly changed at 4 and 8 h after irradiation compared with the sham-irradiated controls. Conclusions: The present study demonstrates for the first time that radiation induces an imbalance between MMP-2 and TIMP-2 levels and suggests that degradation of collagen type IV, a major ECM component of BBB basement membrane, may have a role in the pathogenesis of brain injury.

  3. Effects of monocyte-endothelium interactions on the expression of type IV collagenases in monocytes

    PubMed Central

    LI, YONG-QIN; LIU, RUI; XUE, JIA-HONG; ZHANG, YAN; GAO, DENG-FENG; WU, XIAO-SAN; WANG, CONG-XIA; YANG, YU-BAI

    2015-01-01

    The adhesion of monocytes to endothelial cells is one of the early stages in the development of atherosclerosis. The expression of type IV collagenases, which include matrix metalloproteinase (MMP)-2 and MMP-9, in monocytes is hypothesized to play an important role in monocyte infiltration and transformation into foam cells. The aim of the present study was to examine the effects of monocyte-endothelium interactions on the expression levels of type IV collagenases and their specific inhibitors in monocytes, and to investigate the roles of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in this process. Monocytes were single-cultured or co-cultured with endothelial cells. The expression of the type IV collagenases, MMP-2 and MMP-9, and their specific inhibitors, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2, in monocytes was determined by immunohistochemistry followed by image analysis. The expression levels of MMP-2 and MMP-9 were found to be low in the single-culture monocytes, but increased significantly when the monocytes and endothelial cells were co-cultured. However, treatment with monoclonal TNF-α or IL-1β antibodies partially inhibited the upregulated expression of MMP-2 and MMP-9 in the co-cultured monocytes. Expression of TIMP-1 and TIMP-2 was observed in the single monocyte culture, and a small increase in the expression levels was observed when the monocytes were co-cultured with endothelial cells. Therefore, monocyte-endothlium interactions were shown to increase the expression of type IV collagenases in monocytes, resulting in the loss of balance between MMP-2 and -9 with TIMP-1 and -2. In addition, TNF-α and IL-1β were demonstrated to play important roles in this process. PMID:25574228

  4. Microstructures and Type-IV Creep Damage of High Cr Steel Welds

    NASA Astrophysics Data System (ADS)

    Hongo, Hiromichi; Tabuchi, Masaaki; Takahashi, Yukio

    Creep strength of welded joints in high Cr steels decreases due to the formation of Type-IV creep damage in the heat-affected zone (HAZ) during long-term use at high temperatures. This paper aims to elucidate the processes and mechanisms of Type-IV failure. Creep tests for the welded joints with different groove configurations of Mod.9Cr-1Mo steel were conducted. Distributions of Type-IV creep damages in HAZ of these welds were measured quantitatively, and were compared with FEM computations using damage mechanics analysis. For the welded joints with double U groove, creep voids were observed mostly at 20% below the surface of the plate, and scarcely near surfaces and center of thickness. For the welded joints with single U groove, creep voids were observed inside the plate thickness more than 3mm below the surfaces. From the comparison of experimental damage distributions with FEM analysis, it is considered to be important to take the stress triaxiality into account for the prediction of damage location and fracture life of high Cr ferritic steel welds.

  5. Functional Characterization of Type IV Pili Expressed on Diarrhea-Associated Isolates of Aeromonas species

    PubMed Central

    Kirov, Sylvia M.; O’Donovan, Lisa A.; Sanderson, Kevin

    1999-01-01

    Our past work has shown that long, flexible type IV pili (single or in bundles) are the predominant pili expressed on fecal isolates of diarrhea-associated species of Aeromonas (Aeromonas veronii biovar sobria and A. caviae). They represent a family of type IV pili which we have designated Bfp (for bundle-forming pili). Reports from Japan suggest that Bfp are intestinal colonization factors. This study presents compelling evidence to support this conclusion. Aeromonas bacteria and/or Bfp purified from a strain of A. veronii biovar sobria were shown to adhere to epithelial and intestinal cell lines, freshly isolated human enterocytes, and fresh and fixed human and rabbit intestinal tissues, as determined by light and electron microscopy and immunohistochemical detection. Removal of Bfp by mechanical means decreased adhesion to cell lines by up to 80%. Purified Bfp blocked adhesion of the test strain to intestinal cells in a dose-dependent manner. Adhesion was also blocked by the Fab fraction of anti-Bfp immunoglobulin G. Moreover, ultrastructural studies (ruthenium red staining and transmission and scanning electron microscopy) demonstrated for the first time that Aeromonas adhesion to human enterocytes is pilus mediated and suggested that Bfp may also promote colonization by forming bacterium-to-bacterium linkages. Bfp-positive isolates examined for type IV pilus-mediated twitching motility in agar and slide culture assays developed for Pseudomonas aeruginosa did not, however, exhibit this function. PMID:10496928

  6. Structure and function of the adhesive type IV pilus of Sulfolobus acidocaldarius

    PubMed Central

    Henche, Anna-Lena; Ghosh, Abhrajyoti; Yu, Xiong; Jeske, Torsten; Egelman, Edward; Albers, Sonja-Verena

    2014-01-01

    Archaea display a variety of type IV pili on their surface and employ them in different physiological functions. In the crenarchaeon Sulfolobus acidocaldarius the most abundant surface structure is the aap pilus (archaeal adhesive pilus). The construction of in frame deletions of the aap genes revealed that all the five genes (aapA, aapX, aapE, aapF, aapB) are indispensible for assembly of the pilus and an impact on surface motility and biofilm formation was observed. Our analyses revealed that there exists a regulatory cross-talk between the expression of aap genes and archaella (formerly archaeal flagella) genes during different growth phases. The structure of the aap pilus is entirely different from the known bacterial type IV pili as well as other archaeal type IV pili. An aap pilus displayed 3 stranded helices where there is a rotation per subunit of ~ 138° and a rise per subunit of ~ 5.7 Å. The filaments have a diameter of ~ 110 Å and the resolution was judged to be ~ 9 Å. We concluded that small changes in sequence might be amplified by large changes in higher-order packing. Our finding of an extraordinary stability of aap-pili possibly represents an adaptation to harsh environments that S. acidocaldarius encounters. PMID:23078543

  7. Laminin and Type IV Collagen Isoform Substitutions Occur in Temporally and Spatially Distinct Patterns in Developing Kidney Glomerular Basement Membranes

    PubMed Central

    St. John, Patricia L.; Stroganova, Larysa; Zelenchuk, Adrian; Steenhard, Brooke M.

    2013-01-01

    Kidney glomerular basement membranes (GBMs) undergo laminin and type IV collagen isoform substitutions during glomerular development, which are believed to be required for maturation of the filtration barrier. Specifically, GBMs of earliest glomeruli contain laminin α1β1γ1 and collagen α1α2α1(IV), whereas mature glomeruli contain laminin α5β2γ1 and collagen α3α4α5(IV). Here, we used confocal microscopy to simultaneously evaluate expression of different laminin and collagen IV isoforms in newborn mouse GBMs. Our results show loss of laminin α1 from GBMs in early capillary loop stages and continuous linear deposition of laminin bearing the α5 chain thereafter. In contrast, collagen α1α2α1(IV) persisted in linear patterns into late capillary loop stages, when collagen α3α4α5(IV) first appeared in discontinuous, non-linear patterns. This patchy pattern for collagen α3α4α5(IV) continued into maturing glomeruli where there were lengths of linear, laminin α5-positive GBM entirely lacking either isoform of collagen IV. Relative abundance of laminin and collagen IV mRNAs in newborn and 5-week-old mouse kidneys also differed, with those encoding laminin α1, α5, β1, β2, and γ1, and collagen α1(IV) and α2(IV) chains all significantly declining at 5 weeks, but α3(IV) and α4(IV) were significantly upregulated. We conclude that different biosynthetic mechanisms control laminin and type IV collagen expression in developing glomeruli. PMID:23896970

  8. Anomalous circulation patterns in association with two types of daily precipitation extremes over southeastern China during boreal summer

    NASA Astrophysics Data System (ADS)

    Li, Minggang; Guan, Zhaoyong; Jin, Dachao; Han, Jie; Zhang, Qian

    2016-04-01

    Based on the daily rainfall data from China Meteorological Administration, the tropical cyclone (TC) best track data from Japan Meteorological Agency, and the NCEP-NCAR reanalysis data from NOAA, regional mean daily precipitation extreme (RDPE) events over southeastern China (specifically, the Fujian-Jiangxi region (FJR)) and the associated circulation anomalies are investigated. For the summers of 1979-2011, a total of 105 RDPE events are identified, among which 35 are TC-influenced (TCIn-RDPE) and 70 are TC-free events (TCFr-RDPE). Distinct differences between these two types of RDPEs are found in both their statistical features and the related circulation patterns. TCFr-RDPEs usually occur in June, while TCIn-RDPEs mainly take place during July-August. When TCFr-RDPEs happen, a center of the anomalous cyclonic circulation is observed over the FJR, with an anomalous anticyclonic circulation to the south of this region. The warm/moist air flows from the South China Sea (SCS) and western Pacific meet with colder air from the north, forming a narrow convergent belt of water vapor over the FJR. Simultaneously, positive diabatic forcing anomalies are observed over the FJR, whereas negative anomalies appear over both its south and north sides, facilitating the formation and maintenance of the cyclonic circulation anomaly, as well as the upward motion of the atmosphere, over the FJR. When TCIn-RDPEs occur, southeastern China is dominated by a TC-related stronger anomalous cyclonic circulation. An anomalous anticyclonic circulation in the mid and high latitudes north of the FJR exists in the mid and upper troposphere, opposite to the situation during TCFr-RDPE events. Abundant warm/wet air is carried into the FJR from both the Indian Ocean and the SCS, leading to a large amount of latent heat release over the FJR and inducing strong ascending motion there. Furthermore, large differences are also found in the manifestation of Rossby wave energy propagation between these

  9. Generation of a novel mouse model that recapitulates early and adult onset glycogenosis type IV.

    PubMed

    Akman, H Orhan; Sheiko, Tatiana; Tay, Stacey K H; Finegold, Milton J; Dimauro, Salvatore; Craigen, William J

    2011-11-15

    Glycogen storage disease type IV (GSD IV) is a rare autosomal recessive disorder caused by deficiency of the glycogen branching enzyme (GBE). The diagnostic feature of the disease is the accumulation of a poorly branched form of glycogen known as polyglucosan (PG). The disease is clinically heterogeneous, with variable tissue involvement and age of disease onset. Absence of enzyme activity is lethal in utero or in infancy affecting primarily muscle and liver. However, residual enzyme activity (5-20%) leads to juvenile or adult onset of a disorder that primarily affects muscle as well as central and peripheral nervous system. Here, we describe two mouse models of GSD IV that reflect this spectrum of disease. Homologous recombination was used to insert flippase recognition target recombination sites around exon 7 of the Gbe1 gene and a phosphoglycerate kinase-Neomycin cassette within intron 7, leading to a reduced synthesis of GBE. Mice bearing this mutation (Gbe1(neo/neo)) exhibit a phenotype similar to juvenile onset GSD IV, with wide spread accumulation of PG. Meanwhile, FLPe-mediated homozygous deletion of exon 7 completely eliminated GBE activity (Gbe1(-/-)), leading to a phenotype of lethal early onset GSD IV, with significant in utero accumulation of PG. Adult mice with residual GBE exhibit progressive neuromuscular dysfunction and die prematurely. Differently from muscle, PG in liver is a degradable source of glucose and readily depleted by fasting, emphasizing that there are structural and regulatory differences in glycogen metabolism among tissues. Both mouse models recapitulate typical histological and physiological features of two human variants of branching enzyme deficiency. PMID:21856731

  10. Dissemination of methicillin-resistant Staphylococcus aureus SCCmec type IV and SCCmec type V epidemic clones in a tertiary hospital: challenge to infection control.

    PubMed

    Dhawan, B; Rao, C; Udo, E E; Gadepalli, R; Vishnubhatla, S; Kapil, A

    2015-01-01

    Two-hundred MRSA strains from inpatients with healthcare-associated (HA) and 100 MRSA strains from outpatients with community-associated (CA) skin and soft tissue infections (SSTIs) were tested for antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec) typing, Panton-Valentine leucocidin (PVL) toxin, seh and arcA genes. Based on SCCmec typing, HA-MRSA isolates were further divided into HA-SCCmec I/II/III MRSA and HA-SCCmec IV/V MRSA, and CA-MRSA isolates into CA-SCCmec I/II/III MRSA and CA-SCCmec IV/V MRSA. SCCmec types were further characterized by pulsed-field gel electrophoresis, spa typing and multi-locus sequence typing. Seventy-five (37·5%) HA-MRSA isolates and 83/100 CA-MRSA isolates were SCCmec IV/V genotype. HA-SCCmec IV/V MRSA was associated with malignancy (P = 0·03) and bone fractures (P = 0·02) compared to CA-SCCmec IV/V MRSA. HA-SCCmec IV/V MRSA was associated with PVL gene carriage compared to HA-SCCmec I/II/III MRSA (P < 0·001). ST22-MRSA-IV (EMRSA-15), ST772-MRSA-V, and ST36-MRSA-IV and ST239:EMRSA-I:III were the major clones identified. Our study documents the emergence of SCCmec IV and SCCmec V MRSA clones in an Indian hospital. PMID:24690229

  11. Endovascular Treatment of a Carotid Dissecting Pseudoaneurysm in a Patient with Ehlers-Danlos Syndrome Type IV with Fatal Outcome

    SciTech Connect

    Lim, Siok Ping Duddy, Martin J.

    2008-01-15

    We present a patient with Ehlers-Danlos syndrome type IV (EDS IV) with a carotid dissecting pseudoaneurysm causing severe carotid stenosis. This lesion was treated endovascularly. Unfortunately, the patient died of remote vascular catastrophes (intracranial hemorrhage and abdominal aortic rupture). This unique case illustrates the perils of endovascular treatment of EDS IV patients and the need for preoperative screening for concomitant lesions. It also shows that a dissecting pseudoaneurysm can feasibly be treated with a covered stent and that closure is effective using Angioseal in patients with EDS IV.

  12. Alternative Neisseria spp. type IV pilin glycosylation with a glyceramido acetamido trideoxyhexose residue.

    PubMed

    Chamot-Rooke, Julia; Rousseau, Benoit; Lanternier, Fanny; Mikaty, Guillain; Mairey, Emilie; Malosse, Christian; Bouchoux, Guy; Pelicic, Vladimir; Camoin, Luc; Nassif, Xavier; Duménil, Guillaume

    2007-09-11

    The importance of protein glycosylation in the interaction of pathogenic bacteria with their host is becoming increasingly clear. Neisseria meningitidis, the etiological agent of cerebrospinal meningitis, crosses cellular barriers after adhering to host cells through type IV pili. Pilin glycosylation genes (pgl) are responsible for the glycosylation of PilE, the major subunit of type IV pili, with the 2,4-diacetamido-2,4,6-trideoxyhexose residue. Nearly half of the clinical isolates, however, display an insertion in the pglBCD operon, which is anticipated to lead to a different, unidentified glycosylation. Here the structure of pilin glycosylation was determined in such a strain by "top-down" MS approaches. MALDI-TOF, nanoelectrospray ionization Fourier transform ion cyclotron resonance, and nanoelectrospray ionization quadrupole TOF MS analysis of purified pili preparations originating from N. meningitidis strains, either wild type or deficient for pilin glycosylation, revealed a glycan mass inconsistent with 2,4-diacetamido-2,4,6-trideoxyhexose or any sugar in the databases. This unusual modification was determined by in-source dissociation of the sugar from the protein followed by tandem MS analysis with collision-induced fragmentation to be a hexose modified with a glyceramido and an acetamido group. We further show genetically that the nature of the sugar present on the pilin is determined by the carboxyl-terminal region of the pglB gene modified by the insertion in the pglBCD locus. We thus report a previously undiscovered monosaccharide involved in posttranslational modification of type IV pilin subunits by a MS-based approach and determine the molecular basis of its biosynthesis. PMID:17804791

  13. Characterization of type IV pilus genes in plant growth-promoting Pseudomonas putida WCS358.

    PubMed Central

    de Groot, A; Heijnen, I; de Cock, H; Filloux, A; Tommassen, J

    1994-01-01

    In a search for factors that could contribute to the ability of the plant growth-stimulating Pseudomonas putida WCS358 to colonize plant roots, the organism was analyzed for the presence of genes required for pilus biosynthesis. The pilD gene of Pseudomonas aeruginosa, which has also been designated xcpA, is involved in protein secretion and in the biogenesis of type IV pili. It encodes a peptidase that processes the precursors of the pilin subunits and of several components of the secretion apparatus. Prepilin processing activity could be demonstrated in P. putida WCS358, suggesting that this nonpathogenic strain may contain type IV pili as well. A DNA fragment containing the pilD (xcpA) gene of P. putida was cloned and found to complement a pilD (xcpA) mutation in P. aeruginosa. Nucleotide sequencing revealed, next to the pilD (xcpA) gene, the presence of two additional genes, pilA and pilC, that are highly homologous to genes involved in the biogenesis of type IV pili. The pilA gene encodes the pilin subunit, and pilC is an accessory gene, required for the assembly of the subunits into pili. In comparison with the pil gene cluster in P. aeruginosa, a gene homologous to pilB is lacking in the P. putida gene cluster. Pili were not detected on the cell surface of P. putida itself, not even when pilA was expressed from the tac promoter on a plasmid, indicating that not all the genes required for pilus biogenesis were expressed under the conditions tested. Expression of pilA of P. putida in P. aeruginosa resulted in the production of pili containing P. putida PilA subunits. Images PMID:7905475

  14. Ten tips for treating acne vulgaris in Fitzpatrick skin types IV-VI.

    PubMed

    Spann, Candace Thornton

    2011-06-01

    During the 21st century, people with skin of color will account for a large portion of the US population. According to race projections from the US Census Bureau, persons of African American, Hispanic, Asian and Native American descent will make up nearly half of the total US population by the year 2050. Because of our changing demographics, it is important that all dermatologists become comfortable in treating skin of color. This article provides 10 practical pearls for management of acne vulgaris in patients with Fitzpatrick skin types IV-VI. PMID:21637906

  15. Unveiling Cell Surface and Type IV Secretion Proteins Responsible for Archaeal Rudivirus Entry

    PubMed Central

    Deng, Ling; He, Fei; Bhoobalan-Chitty, Yuvaraj; Martinez-Alvarez, Laura; Guo, Yang

    2014-01-01

    Sulfolobus mutants resistant to archaeal lytic virus Sulfolobus islandicus rod-shaped virus 2 (SIRV2) were isolated, and mutations were identified in two gene clusters, cluster sso3138 to sso3141 and cluster sso2386 and sso2387, encoding cell surface and type IV secretion proteins, respectively. The involvement of the mutations in the resistance was confirmed by genetic complementation. Blocking of virus entry into the mutants was demonstrated by the lack of early gene transcription, strongly supporting the idea of a role of the proteins in SIRV2 entry. PMID:24965447

  16. Translocation of Helicobacter pylori CagA into Gastric Epithelial Cells by Type IV Secretion

    NASA Astrophysics Data System (ADS)

    Odenbreit, Stefan; Püls, Jürgen; Sedlmaier, Bettina; Gerland, Elke; Fischer, Wolfgang; Haas, Rainer

    2000-02-01

    The Gram-negative bacterium Helicobacter pylori is a causative agent of gastritis and peptic ulcer disease in humans. Strains producing the CagA antigen (cagA+) induce strong gastric inflammation and are strongly associated with gastric adenocarcinoma and MALT lymphoma. We show here that such strains translocate the bacterial protein CagA into gastric epithelial cells by a type IV secretion system, encoded by the cag pathogenicity island. CagA is tyrosine-phosphorylated and induces changes in the tyrosine phosphorylation state of distinct cellular proteins. Modulation of host cells by bacterial protein translocation adds a new dimension to the chronic Helicobacter infection with yet unknown consequences.

  17. Type IV acromioclavicular joint dislocation associated with a mid-shaft clavicle malunion

    PubMed Central

    Mohammed, Khalid D.; Stachiw, Danielle; Malone, Alex A.

    2016-01-01

    This reports presents the case of a combined clavicle fracture malunion and chronic Type IV acromioclavicular (AC) joint dislocation. The patient was seen acutely in the emergency department following a mountain bike accident at which time the clavicle fracture was identified and managed conservatively however the AC dislocation was not diagnosed. The patient presented 25 months following the injury with persistent pain and disability and was treated with clavicle osteotomy and AC stabilization. We document the clinical details, surgical treatment and outcome. PMID:26980988

  18. Type IV acromioclavicular joint dislocation associated with a mid-shaft clavicle malunion.

    PubMed

    Mohammed, Khalid D; Stachiw, Danielle; Malone, Alex A

    2016-01-01

    This reports presents the case of a combined clavicle fracture malunion and chronic Type IV acromioclavicular (AC) joint dislocation. The patient was seen acutely in the emergency department following a mountain bike accident at which time the clavicle fracture was identified and managed conservatively however the AC dislocation was not diagnosed. The patient presented 25 months following the injury with persistent pain and disability and was treated with clavicle osteotomy and AC stabilization. We document the clinical details, surgical treatment and outcome. PMID:26980988

  19. DSMC Simulation of Shock/Shock Interactions: Emphasis on Type IV Interactions

    NASA Technical Reports Server (NTRS)

    Moss, J. N.; Pot, T.; Chanetz, B.; Lefebvre, M.

    1999-01-01

    This paper presents the results of a numerical study of shock/shock interactions that include both the Edney type IV and type III interactions, with emphasis on the type IV interactions. Computations are made using the direct simulation Monte Carlo (DSMC) method of Bird for Mach 10 air flow, as produced in the ONERA R5Ch low-density wind tunnel. The simulations include the flow about a shock generator which creates a relatively weak oblique shock that impinges on a much stronger cylinder bow shock. The sensitivity and characteristics of the interactions are examined by varying the horizontal distance separating the shock generator leading edge and cylinder. Results of the simulation for one separation distance are compared with wind tunnel measurements. Comparisons are made for surface heating and pressure and for flow-field values of density and rotational temperatures, as obtained with the Dual-line Coherent Anti-Stokes Scattering (DL-CARS) technique. The comparisons between experiment and calculation yield a consistent description of the shock interaction features and a consistent description of the surface heating and pressure distributions, with the exception of the peak values-the computed values being greater than the measured values.

  20. Collagen type IV of Drosophila is stockpiled in the growing oocyte and differentially located during early stages of embryogenesis.

    PubMed

    Knibiehler, B; Mirre, C; Le Parco, Y

    1990-05-01

    We have developed and characterized a battery of specific polyclonal antibodies directed against specific portions of the alpha-chain of collagen type IV synthesized in Drosophila by the gene DCg1. Here, we describe the use of these antibodies together with in situ hybridization experiments in an attempt to study the expression and localization of collagen type IV during Drosophila oogenesis and early embryogenesis. The results clearly demonstrate that DCg1 is maternally expressed by follicle cells and that the collagen type IV chain produced is stockpiled in the growing oocyte. During the gastrulation stages, this component of Drosophila basement membranes concentrated on cells involved in the gradual invaginations leading to morphogenetic furrows. The presence of collagen type IV, which is an RGD-bearing molecule, during early stages of Drosophila development is discussed in comparison with the crucial, active role its vertebrate counterpart is supposed to play in morphogenetic processes. PMID:2117479

  1. Sequence analyses of type IV pili from Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus.

    PubMed

    Aagesen, Alisha M; Häse, Claudia C

    2012-08-01

    Bacterial surface structures called pili have been studied extensively for their role as possible colonization factors. Most sequenced Vibrio genomes predict a variety of pili genes in these organisms, including several types of type IV pili. In particular, the mannose-sensitive hemagglutinin (MSHA) and the PilA pili, also known as the chitin-regulated pilus (ChiRP), are type IVa pili commonly found in Vibrio genomes and have been shown to play a role in the colonization of Vibrio species in the environment and/or host tissue. Here, we report sequence comparisons of two type IVa pilin subunit genes, mshA and pilA, and their corresponding amino acid sequences, for several strains from the three main human pathogenic Vibrio species, V. cholerae, V. parahaemolyticus, and V. vulnificus. We identified specific groupings of these two genes in V. cholerae, whereas V. parahaemolyticus and V. vulnificus strains had no apparent allelic clusters, and these genes were strikingly divergent. These results were compared with other genes from the MSHA and PilA operons as well as another Vibrio pili from the type IVb group, the toxin co-regulated pilus (TCP) from V. cholerae. Our data suggest that a selective pressure exists to cause these strains to vary their MSHA and PilA pilin subunits. Interestingly, V. cholerae strains possessing TCP have the same allele for both mshA and pilA. In contrast, V. cholerae isolates without TCP have polymorphisms in their mshA and pilA sequences similar to what was observed for both V. parahaemolyticus and V. vulnificus. This data suggests a possible linkage between host interactions and maintaining a highly conserved type IV pili sequence in V. cholerae. Although the mechanism underlying this intriguing diversity has yet to be elucidated, our analyses are an important first step towards gaining insights into the various aspects of Vibrio ecology. PMID:22383120

  2. Galactose recognition by a tetrameric C-type lectin, CEL-IV, containing the EPN carbohydrate recognition motif.

    PubMed

    Hatakeyama, Tomomitsu; Kamiya, Takuro; Kusunoki, Masami; Nakamura-Tsuruta, Sachiko; Hirabayashi, Jun; Goda, Shuichiro; Unno, Hideaki

    2011-03-25

    CEL-IV is a C-type lectin isolated from a sea cucumber, Cucumaria echinata. This lectin is composed of four identical C-type carbohydrate-recognition domains (CRDs). X-ray crystallographic analysis of CEL-IV revealed that its tetrameric structure was stabilized by multiple interchain disulfide bonds among the subunits. Although CEL-IV has the EPN motif in its carbohydrate-binding sites, which is known to be characteristic of mannose binding C-type CRDs, it showed preferential binding of galactose and N-acetylgalactosamine. Structural analyses of CEL-IV-melibiose and CEL-IV-raffinose complexes revealed that their galactose residues were recognized in an inverted orientation compared with mannose binding C-type CRDs containing the EPN motif, by the aid of a stacking interaction with the side chain of Trp-79. Changes in the environment of Trp-79 induced by binding to galactose were detected by changes in the intrinsic fluorescence and UV absorption spectra of WT CEL-IV and its site-directed mutants. The binding specificity of CEL-IV toward complex oligosaccharides was analyzed by frontal affinity chromatography using various pyridylamino sugars, and the results indicate preferential binding to oligosaccharides containing Galβ1-3/4(Fucα1-3/4)GlcNAc structures. These findings suggest that the specificity for oligosaccharides may be largely affected by interactions with amino acid residues in the binding site other than those determining the monosaccharide specificity. PMID:21247895

  3. Fine Structure in Type IV Solar Radio Bursts during three major Solar Events of October-November 2003 observed by Artemis IV.

    NASA Astrophysics Data System (ADS)

    Tsitsipis, P.; Kontogeorgos, A.; Caroubalos, C.; Moussas, X.; Hillaris, A.; Preka-Papadema, P.; Bougeret, J.-L.; Alissandrakis, C.; Dumas, G.; Polygiannakis, J.

    The fine structure in three solar type IV radio bursts was studied using the French-Greek ARTEMIS-IV multichannel radio spectrograph. The bursts were recorded during three major solar events, on the 26 and 28 October.and 3 Nov. 2003; these we associated with intense flares and CMEs. The observed fine structure includes intermediate drift bursts (fibers) and pulsations. The complexity and overlapping of the various spectral characteristics necessitated the utilization of certain, 2D-FFT based, filtering processes, aiming firstly at structure detection in the frequency-time plane (ie the dynamic spectrum) and secondly in the separation of fibers and pulsations and the suppression of the type IV continuum. This methodology results also to the fibers frequency drift rate distributions and their evolution in time. These fiber frequency drift distributions may be interpreted as the exciter velocity distributions, using a Newkirk coronal density model; the latter may be used as diagnostics of the magnetic field restructuring and energy release during a solar energetic event (flare and/or CME). Artemis IV will provide complementary data to the STEREO/WAVES experiment.

  4. Glycosylation Modulates Melanoma Cell α2β1 and α3β1 Integrin Interactions with Type IV Collagen*

    PubMed Central

    Stawikowski, Maciej J.; Aukszi, Beatrix; Stawikowska, Roma; Cudic, Mare; Fields, Gregg B.

    2014-01-01

    Although type IV collagen is heavily glycosylated, the influence of this post-translational modification on integrin binding has not been investigated. In the present study, galactosylated and nongalactosylated triple-helical peptides have been constructed containing the α1(IV)382–393 and α1(IV)531–543 sequences, which are binding sites for the α2β1 and α3β1 integrins, respectively. All peptides had triple-helical stabilities of 37 °C or greater. The galactosylation of Hyl393 in α1(IV)382–393 and Hyl540 and Hyl543 in α1(IV)531–543 had a dose-dependent influence on melanoma cell adhesion that was much more pronounced in the case of α3β1 integrin binding. Molecular modeling indicated that galactosylation occurred on the periphery of α2β1 integrin interaction with α1(IV)382–393 but right in the middle of α3β1 integrin interaction with α1(IV)531–543. The possibility of extracellular deglycosylation of type IV collagen was investigated, but no β-galactosidase-like activity capable of collagen modification was found. Thus, glycosylation of collagen can modulate integrin binding, and levels of glycosylation could be altered by reduction in expression of glycosylation enzymes but most likely not by extracellular deglycosylation activity. PMID:24958723

  5. Myocardial infarction resulting from coronary artery dissection in an adolescent with Ehlers-Danlos syndrome type IV due to a type III collagen mutation.

    PubMed Central

    Adès, L. C.; Waltham, R. D.; Chiodo, A. A.; Bateman, J. F.

    1995-01-01

    Ehlers-Danlos syndrome encompasses a group of inherited disorders of connective tissue, some of which are characterised by abnormalities of collagen metabolism. The chromosomal location, identified genes and biochemical defects, inheritance pattern, and clinical features for the various known subtypes are outlined. Prenatal diagnosis is possible for types IV, VI, VIIA1, and VIIA2. An unusual presentation of type IV Ehlers-Danlos syndrome in a 16 year old boy with an anterior myocardial infarction resulting from dissection of the left anterior descending coronary artery is reported here. A clinical diagnosis of type IV Ehlers-Danlos syndrome was made subsequently and confirmed by the reduced production, impaired secretion, and abnormally slow electrophoretic migration of type III collagen, indicating an underlying mutation in the COL3A1 gene. This patient represents the first case of type IV Ehlers-Danlos syndrome with symptomatic coronary artery dissection. Images PMID:7546986

  6. Open angle glaucoma in a case of Type IV Ehler Danlos syndrome: a rarely reported association.

    PubMed

    Mitra, Arijit; Ramakrishnan, R; Kader, Mohideen Abdul

    2014-08-01

    A 26-year-old male presented to us with defective vision in the left eye. He had best corrected visual acuity (BCVA) of hand movement (HM) in right eye and 6/9 in left eye. He had ptosis with ectropion in both eyes and relative afferent pupillary defect (RAPD) in right eye. Intraocular pressure (IOP) was 46 and 44 mmHg in right and left eye, respectively. Fundus showed glaucomatous optic atrophy (GOA) in right eye and cup disc ratio (CDR) of 0.75 with bipolar rim thinning in left eye. Systemic examination showed hyperextensible skin and joints, acrogeria, hypodontia, high arched palate, and varicose veins. He gave history of easy bruising and tendency to fall and history of intestinal rupture 5 years ago for which he had undergone surgery. He was diagnosed as a case of Type IV Ehler-Danlos syndrome (EDS) with open angle glaucoma. He underwent trabeculectomy in both eyes. This is a rare case that shows glaucoma in a patient of EDS Type IV. Very few such cases have been reported in literature. PMID:25230966

  7. A novel GBE1 gene variant in a child with glycogen storage disease type IV.

    PubMed

    Said, Samar M; Murphree, Marine I; Mounajjed, Taofic; El-Youssef, Mounif; Zhang, Lizhi

    2016-08-01

    Glycogen storage disease type IV is an autosomal recessive disorder of carbohydrates caused by deficiency of amylo-1-4-glycanoglycosyltransferase, which leads to accumulation of amylopectin-like polysaccharides in tissues including liver, heart and neuromuscular system. More than 40 different mutations in the glycogen branching enzyme gene (GBE1) have been described. In this study, we report a 2-year-old boy who presented with developmental delay and muscle weakness. He subsequently was diagnosed with glycogen storage disease type IV based on a liver biopsy histology and electron microscopy. Glycogen branching enzyme activity was in the low range. Genetic analysis demonstrated a novel heterozygous variant (c.760A>G; p.Thr254Ala) in exon 6 of the GBE1 gene, which is believed to be pathogenic. This variant was inherited from the patient's mother who was asymptomatic with normal glycogen branching enzyme activity. Whole-exome sequencing failed to reveal additional variations in the GBE1 gene. PMID:27107456

  8. SPARC Promotes Cell Invasion In Vivo by Decreasing Type IV Collagen Levels in the Basement Membrane

    PubMed Central

    Morrissey, Meghan A.; Jayadev, Ranjay; Miley, Ginger R.; Blebea, Catherine A.; Chi, Qiuyi; Ihara, Shinji; Sherwood, David R.

    2016-01-01

    Overexpression of SPARC, a collagen-binding glycoprotein, is strongly associated with tumor invasion through extracellular matrix in many aggressive cancers. SPARC regulates numerous cellular processes including integrin-mediated cell adhesion, cell signaling pathways, and extracellular matrix assembly; however, the mechanism by which SPARC promotes cell invasion in vivo remains unclear. A main obstacle in understanding SPARC function has been the difficulty of visualizing and experimentally examining the dynamic interactions between invasive cells, extracellular matrix and SPARC in native tissue environments. Using the model of anchor cell invasion through the basement membrane (BM) extracellular matrix in Caenorhabditis elegans, we find that SPARC overexpression is highly pro-invasive and rescues BM transmigration in mutants with defects in diverse aspects of invasion, including cell polarity, invadopodia formation, and matrix metalloproteinase expression. By examining BM assembly, we find that overexpression of SPARC specifically decreases levels of BM type IV collagen, a crucial structural BM component. Reduction of type IV collagen mimicked SPARC overexpression and was sufficient to promote invasion. Tissue-specific overexpression and photobleaching experiments revealed that SPARC acts extracellularly to inhibit collagen incorporation into BM. By reducing endogenous SPARC, we also found that SPARC functions normally to traffic collagen from its site of synthesis to tissues that do not express collagen. We propose that a surplus of SPARC disrupts extracellular collagen trafficking and reduces BM collagen incorporation, thus weakening the BM barrier and dramatically enhancing its ability to be breached by invasive cells. PMID:26926673

  9. Characterization of adhesion threads of Deinococcus geothermalis as type IV pili.

    PubMed

    Saarimaa, C; Peltola, M; Raulio, M; Neu, T R; Salkinoja-Salonen, M S; Neubauer, P

    2006-10-01

    Deinococcus geothermalis E50051 forms tenuous biofilms on paper machine surfaces. Field emission electron microscopy analysis revealed peritrichous appendages which mediated cell-to-surface and cell-to-cell interactions but were absent in planktonically grown cells. The major protein component of the extracellular extract of D. geothermalis had an N-terminal sequence similar to the fimbrial protein pilin annotated in the D. geothermalis DSM 11300 draft sequence. It also showed similarity to the type IV pilin sequence of D. radiodurans and several gram-negative pathogenic bacteria. Other proteins in the extract had N-terminal sequences identical to D. geothermalis proteins with conservative motifs for serine proteases, metallophosphoesterases, and proteins whose function is unknown. Periodic acid-Schiff staining for carbohydrates indicated that these extracellular proteins may be glycosylated. A further confirmation for the presence of glycoconjugates on the cell surface was obtained by confocal laser scanning imaging of living D. geothermalis cells stained with Amaranthus caudatus lectin, which specifically binds to galactose residues. The results indicate that the thread-like appendages of D. geothermalis E50051 are glycosylated type IV pili, bacterial attachment organelles which have thus far not been described for the genus Deinococcus. PMID:16980504

  10. SPARC Promotes Cell Invasion In Vivo by Decreasing Type IV Collagen Levels in the Basement Membrane.

    PubMed

    Morrissey, Meghan A; Jayadev, Ranjay; Miley, Ginger R; Blebea, Catherine A; Chi, Qiuyi; Ihara, Shinji; Sherwood, David R

    2016-02-01

    Overexpression of SPARC, a collagen-binding glycoprotein, is strongly associated with tumor invasion through extracellular matrix in many aggressive cancers. SPARC regulates numerous cellular processes including integrin-mediated cell adhesion, cell signaling pathways, and extracellular matrix assembly; however, the mechanism by which SPARC promotes cell invasion in vivo remains unclear. A main obstacle in understanding SPARC function has been the difficulty of visualizing and experimentally examining the dynamic interactions between invasive cells, extracellular matrix and SPARC in native tissue environments. Using the model of anchor cell invasion through the basement membrane (BM) extracellular matrix in Caenorhabditis elegans, we find that SPARC overexpression is highly pro-invasive and rescues BM transmigration in mutants with defects in diverse aspects of invasion, including cell polarity, invadopodia formation, and matrix metalloproteinase expression. By examining BM assembly, we find that overexpression of SPARC specifically decreases levels of BM type IV collagen, a crucial structural BM component. Reduction of type IV collagen mimicked SPARC overexpression and was sufficient to promote invasion. Tissue-specific overexpression and photobleaching experiments revealed that SPARC acts extracellularly to inhibit collagen incorporation into BM. By reducing endogenous SPARC, we also found that SPARC functions normally to traffic collagen from its site of synthesis to tissues that do not express collagen. We propose that a surplus of SPARC disrupts extracellular collagen trafficking and reduces BM collagen incorporation, thus weakening the BM barrier and dramatically enhancing its ability to be breached by invasive cells. PMID:26926673

  11. Open angle glaucoma in a case of Type IV Ehler Danlos syndrome: A rarely reported association

    PubMed Central

    Mitra, Arijit; Ramakrishnan, R.; Kader, Mohideen Abdul

    2014-01-01

    A 26-year-old male presented to us with defective vision in the left eye. He had best corrected visual acuity (BCVA) of hand movement (HM) in right eye and 6/9 in left eye. He had ptosis with ectropion in both eyes and relative afferent pupillary defect (RAPD) in right eye. Intraocular pressure (IOP) was 46 and 44 mmHg in right and left eye, respectively. Fundus showed glaucomatous optic atrophy (GOA) in right eye and cup disc ratio (CDR) of 0.75 with bipolar rim thinning in left eye. Systemic examination showed hyperextensible skin and joints, acrogeria, hypodontia, high arched palate, and varicose veins. He gave history of easy bruising and tendency to fall and history of intestinal rupture 5 years ago for which he had undergone surgery. He was diagnosed as a case of Type IV Ehler-Danlos syndrome (EDS) with open angle glaucoma. He underwent trabeculectomy in both eyes. This is a rare case that shows glaucoma in a patient of EDS Type IV. Very few such cases have been reported in literature. PMID:25230966

  12. Identification, Immunogenicity and Crossreactivity of Type IV Pilin and Pilin-like Proteins from Clostridium difficile

    PubMed Central

    Maldarelli, Grace A.; De Masi, Leon; von Rosenvinge, Erik C.; Carter, Mihaela; Donnenberg, Michael S.

    2014-01-01

    The Gram-positive anaerobe Clostridium difficile is the major cause of nosocomial diarrhea; manifestations of infection include diarrhea, pseudomembranous colitis, and death. Genes for type IV pili, a bacterial nanofiber often involved in colonization and until relatively recently described only in Gram-negatives, are present in all members of the Clostridiales. We hypothesized that any pilins encoded in the C. difficile genome would be immunogenic, as has been shown with pilins from Gram-negative organisms. We describe nine pilin or pilin-like protein genes, for which we introduce a coherent nomenclature, in the C. difficile R20291 genome. The nine predicted pilin or pilin-like proteins have relatively conserved N-terminal hydrophobic regions, but diverge at their C-termini. Analysis of synonymous and nonsynonymous substitutions revealed evidence of diversifying selective pressure in two pilin genes. Six of the nine identified proteins were purified and used to immunize mice. Immunization of mice with each individual protein generated antibody responses that varied in titer and crossreactivity, a notable result given the low amino acid sequence identity among the pilins. Further studies in other small mammals mirrored our results in mice. Our results illuminate components of the C. difficile type IV pilus, and help identify targets for an anti-C. difficile vaccine. PMID:24550179

  13. Motion of the sources for type II and type IV radio bursts and flare-associated interplanetary disturbances

    NASA Technical Reports Server (NTRS)

    Sakurai, K.; Chao, J. K.

    1974-01-01

    Shock waves are indirectly observed as the source of type II radio bursts, whereas magnetic bottles are identified as the source of moving metric type IV radio bursts. The difference between the expansion speeds of these waves and bottles is examined during their generation and propagation near the flare regions. It is shown that, although generated in the explosive phase of flares, the bottles behave quite differently from the waves and that the bottles are generally much slower than the waves. It has been suggested that the waves are related to flare-associated interplanetary disturbances which produce SSC geomagnetic storms. These disturbances may, therefore, be identified as interplanetary shock waves. The relationship among magnetic bottles, shock waves near the sun, and flare-associated disturbances in interplanetary space is briefly discussed.

  14. Bright but slow - Type II supernovae from OGLE-IV - implications for magnitude-limited surveys

    NASA Astrophysics Data System (ADS)

    Poznanski, D.; Kostrzewa-Rutkowska, Z.; Wyrzykowski, L.; Blagorodnova, N.

    2015-05-01

    We study a sample of 11 Type II supernovae (SNe) discovered by the OGLE-IV survey. All objects have well-sampled I-band light curves, and at least one spectrum. We find that two or three of the 11 SNe have a declining light curve, and spectra consistent with other SNe II-L, while the rest have plateaus that can be as short as 70 d, unlike the 100 d typically found in nearby galaxies. The OGLE SNe are also brighter, and show that magnitude-limited surveys find SNe that are different than usually found in nearby galaxies. We discuss this sample in the context of understanding Type II SNe as a class and their suggested use as standard candles.

  15. Structure of a type IV pilus machinery in the open and closed state

    PubMed Central

    Gold, Vicki AM; Salzer, Ralf; Averhoff, Beate; Kühlbrandt, Werner

    2015-01-01

    Proteins of the secretin family form large macromolecular complexes, which assemble in the outer membrane of Gram-negative bacteria. Secretins are major components of type II and III secretion systems and are linked to extrusion of type IV pili (T4P) and to DNA uptake. By electron cryo-tomography of whole Thermus thermophilus cells, we determined the in situ structure of a T4P molecular machine in the open and the closed state. Comparison reveals a major conformational change whereby the N-terminal domains of the central secretin PilQ shift by ∼30 Å, and two periplasmic gates open to make way for pilus extrusion. Furthermore, we determine the structure of the assembled pilus. DOI: http://dx.doi.org/10.7554/eLife.07380.001 PMID:25997099

  16. Fine Structure of Metric Type IV Radio Bursts Observed with the ARTEMIS-IV Radio-Spectrograph: Association with Flares and Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Bouratzis, C.; Hillaris, A.; Alissandrakis, C. E.; Preka-Papadema, P.; Moussas, X.; Caroubalos, C.; Tsitsipis, P.; Kontogeorgos, A.

    2015-01-01

    Fine structures embedded in type IV burst continua may be used as diagnostics of the magnetic-field restructuring and the corresponding energy release associated with the low-corona development of flare or coronal mass ejection (CME) events. A catalog of 36 type IV bursts observed with the SAO receiver of the ARTEMIS-IV solar radio-spectrograph in the 450 - 270 MHz range at high cadence (0.01 sec) was compiled; the fine structures were classified into five basic classes with two or more subclasses each. The time of fine-structure emission was compared with the injection of energetic electrons as recorded by hard X-ray and microwave emission, the soft X-ray (SXR) light curves and the CME onset time. Our results indicate a very tight temporal association between energy release episodes and pulsations, spikes, narrow-band bursts of the type III family, and zebra bursts. Of the remaining categories, the featureless broadband continuum starts near the time of the first energy release, between the CME onset and the SXR peak, but extends for several tens of minutes after that, covering almost the full extent of the flare-CME event. The intermediate drift bursts, fibers in their majority, mostly follow the first energy release, but have a wider distribution than other fine structures.

  17. On the source of the dust extinction in type Ia supernovae and the discovery of anomalously strong Na I absorption

    SciTech Connect

    Phillips, M. M.; Morrell, Nidia; Hsiao, E. Y.; Campillay, Abdo; Contreras, Carlos; Simon, Joshua D.; Burns, Christopher R.; Persson, Sven E.; Thompson, I. B.; Freedman, Wendy L.; Cox, Nick L. J.; Foley, Ryan J.; Karakas, Amanda I.; Patat, F.; Sternberg, A.; Williams, R. E.; Gal-Yam, A.; Leonard, D. C.; Stritzinger, Maximilian; Folatelli, Gastón; and others

    2013-12-10

    High-dispersion observations of the Na I D λλ5890, 5896 and K I λλ7665, 7699 interstellar lines, and the diffuse interstellar band at 5780 Å in the spectra of 32 Type Ia supernovae are used as an independent means of probing dust extinction. We show that the dust extinction of the objects where the diffuse interstellar band at 5780 Å is detected is consistent with the visual extinction derived from the supernova colors. This strongly suggests that the dust producing the extinction is predominantly located in the interstellar medium of the host galaxies and not in circumstellar material associated with the progenitor system. One quarter of the supernovae display anomalously large Na I column densities in comparison to the amount of dust extinction derived from their colors. Remarkably, all of the cases of unusually strong Na I D absorption correspond to 'Blueshifted' profiles in the classification scheme of Sternberg et al. This coincidence suggests that outflowing circumstellar gas is responsible for at least some of the cases of anomalously large Na I column densities. Two supernovae with unusually strong Na I D absorption showed essentially normal K I column densities for the dust extinction implied by their colors, but this does not appear to be a universal characteristic. Overall, we find the most accurate predictor of individual supernova extinction to be the equivalent width of the diffuse interstellar band at 5780 Å, and provide an empirical relation for its use. Finally, we identify ways of producing significant enhancements of the Na abundance of circumstellar material in both the single-degenerate and double-degenerate scenarios for the progenitor system.

  18. An extracellular protease of Streptococcus gordonii hydrolyzes type IV collagen and collagen analogues.

    PubMed

    Juarez, Z E; Stinson, M W

    1999-01-01

    Streptococcus gordonii is a frequent cause of infective bacterial endocarditis, but its mechanisms of virulence are not well defined. In this study, streptococcal proteases were recovered from spent chemically defined medium (CDM) and fractionated by ammonium sulfate precipitation and by ion-exchange and gel filtration column chromatography. Three proteases were distinguished by their different solubilities in ammonium sulfate and their specificities for synthetic peptides. One of the enzymes cleaved collagen analogs Gly-Pro 4-methoxy-beta-naphthylamide, 2-furanacryloyl-Leu-Gly-Pro-Ala (FALGPA), and p-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-Arg (pZ-peptide) and was released from the streptococci while complexed to peptidoglycan fragments. Treatment of this protease with mutanolysin reduced its 180- to 200-kDa mass to 98 kDa without loss of enzymatic activity. The purified protease cleaved bovine gelatin, human placental type IV collagen, and the Aalpha chain of fibrinogen but not albumin, fibronectin, laminin, or myosin. Enzyme activity was inhibited by phenylmethylsulfonyl fluoride, indicating that it is a serine-type protease. Maximum production of the 98-kDa protease occurred during growth of S. gordonii CH1 in CDM containing 0.075% total amino acids at pH 7.0 with minimal aeration. Higher initial concentrations of amino acids prevented the release of the protease without reducing cell-associated enzyme levels, and the addition of an amino acid mixture to an actively secreting culture stopped further enzyme release. The purified protease was stored frozen at -20 degreesC for several months or heated at 50 degreesC for 10 min without loss of activity. These data indicate that S. gordonii produces an extracellular gelatinase/type IV collagenase during growth in medium containing minimal concentrations of free amino acids. Thus, the extracellular enzyme is a potential virulence factor in the amino acid-stringent, thrombotic, valvular lesions of bacterial

  19. Structural characterization of ribosome recruitment and translocation by type IV IRES.

    PubMed

    Murray, Jason; Savva, Christos G; Shin, Byung-Sik; Dever, Thomas E; Ramakrishnan, V; Fernández, Israel S

    2016-01-01

    Viral mRNA sequences with a type IV IRES are able to initiate translation without any host initiation factors. Initial recruitment of the small ribosomal subunit as well as two translocation steps before the first peptidyl transfer are essential for the initiation of translation by these mRNAs. Using electron cryomicroscopy (cryo-EM) we have structurally characterized at high resolution how the Cricket Paralysis Virus Internal Ribosomal Entry Site (CrPV-IRES) binds the small ribosomal subunit (40S) and the translocation intermediate stabilized by elongation factor 2 (eEF2). The CrPV-IRES restricts tvhe otherwise flexible 40S head to a conformation compatible with binding the large ribosomal subunit (60S). Once the 60S is recruited, the binary CrPV-IRES/80S complex oscillates between canonical and rotated states (Fernández et al., 2014; Koh et al., 2014), as seen for pre-translocation complexes with tRNAs. Elongation factor eEF2 with a GTP analog stabilizes the ribosome-IRES complex in a rotated state with an extra ~3 degrees of rotation. Key residues in domain IV of eEF2 interact with pseudoknot I (PKI) of the CrPV-IRES stabilizing it in a conformation reminiscent of a hybrid tRNA state. The structure explains how diphthamide, a eukaryotic and archaeal specific post-translational modification of a histidine residue of eEF2, is involved in translocation. PMID:27159451

  20. Classification of bulimic-type eating disorders: from DSM-IV to DSM-5.

    PubMed

    Mond, Jonathan M

    2013-01-01

    Proposed changes to the classification of bulimic-type eating disorders in the lead up to the publication of DSM-5 are reviewed. Several of the proposed changes, including according formal diagnostic status to binge eating disorder (BED), removing the separation of bulimia nervosa (BN) into purging and non-purging subtypes, and reducing the binge frequency threshold from twice per week to once per week for both BN and (BED), have considerable empirical evidence to support them and will likely have the effect of facilitating clinical practice, improving access to care, improving public and professional awareness and understanding of these disorders and stimulating the additional research needed to address at least some problematic issues. However, the omission of any reference to variants of BN characterized by subjective, but not objective, binge eating episodes, and to the undue influence of weight or shape on self-evaluation or similar cognitive criterion in relation to the diagnosis of BED, is regrettable, given their potential to inform clinical and research practice and given that there is considerable evidence to support specific reference to these distinctions. Other aspects of the proposed criteria, such as retention of behavioral indicators of impaired control associated with binge eating and the presence of marked distress regarding binge eating among the diagnostic for BED, appear anomalous in that there is little or no evidence to support their validity or clinical utility. It is hoped that these issues will be addressed in final phase of the DSM-5 development process. PMID:24999412

  1. Classification of bulimic-type eating disorders: from DSM-IV to DSM-5

    PubMed Central

    2013-01-01

    Proposed changes to the classification of bulimic-type eating disorders in the lead up to the publication of DSM-5 are reviewed. Several of the proposed changes, including according formal diagnostic status to binge eating disorder (BED), removing the separation of bulimia nervosa (BN) into purging and non-purging subtypes, and reducing the binge frequency threshold from twice per week to once per week for both BN and (BED), have considerable empirical evidence to support them and will likely have the effect of facilitating clinical practice, improving access to care, improving public and professional awareness and understanding of these disorders and stimulating the additional research needed to address at least some problematic issues. However, the omission of any reference to variants of BN characterized by subjective, but not objective, binge eating episodes, and to the undue influence of weight or shape on self-evaluation or similar cognitive criterion in relation to the diagnosis of BED, is regrettable, given their potential to inform clinical and research practice and given that there is considerable evidence to support specific reference to these distinctions. Other aspects of the proposed criteria, such as retention of behavioral indicators of impaired control associated with binge eating and the presence of marked distress regarding binge eating among the diagnostic for BED, appear anomalous in that there is little or no evidence to support their validity or clinical utility. It is hoped that these issues will be addressed in final phase of the DSM-5 development process. PMID:24999412

  2. Crucial role for the VWF A1 domain in binding to type IV collagen.

    PubMed

    Flood, Veronica H; Schlauderaff, Abraham C; Haberichter, Sandra L; Slobodianuk, Tricia L; Jacobi, Paula M; Bellissimo, Daniel B; Christopherson, Pamela A; Friedman, Kenneth D; Gill, Joan Cox; Hoffmann, Raymond G; Montgomery, Robert R

    2015-04-01

    Von Willebrand factor (VWF) contains binding sites for platelets and for vascular collagens to facilitate clot formation at sites of injury. Although previous work has shown that VWF can bind type IV collagen (collagen 4), little characterization of this interaction has been performed. We examined the binding of VWF to collagen 4 in vitro and extended this characterization to a murine model of defective VWF-collagen 4 interactions. The interactions of VWF and collagen 4 were further studied using plasma samples from a large study of both healthy controls and subjects with different types of von Willebrand disease (VWD). Our results show that collagen 4 appears to bind VWF exclusively via the VWF A1 domain, and that specific sequence variations identified through VWF patient samples and through site-directed mutagenesis in the VWF A1 domain can decrease or abrogate this interaction. In addition, VWF-dependent platelet binding to collagen 4 under flow conditions requires an intact VWF A1 domain. We observed that decreased binding to collagen 4 was associated with select VWF A1 domain sequence variations in type 1 and type 2M VWD. This suggests an additional mechanism through which VWF variants may alter hemostasis. PMID:25662333

  3. Crucial role for the VWF A1 domain in binding to type IV collagen

    PubMed Central

    Schlauderaff, Abraham C.; Haberichter, Sandra L.; Slobodianuk, Tricia L.; Jacobi, Paula M.; Bellissimo, Daniel B.; Christopherson, Pamela A.; Friedman, Kenneth D.; Gill, Joan Cox; Hoffmann, Raymond G.; Montgomery, Robert R.; Abshire, T.; Dunn, A.; Bennett, C.; Lusher, J.; Rajpurkar, M.; Brown, D.; Shapiro, A.; Lentz, S.; Gill, J.; Leissinger, C.; Ragni, M.; Hord, J.; Manco-Johnson, M.; Strouse, J.; Ma, A.; Valentino, L.; Boggio, L.; Sharathkumar, A.; Gruppo, R.; Kerlin, B.; Journeycake, J.; Kulkarni, R.; Green, D.; Mahoney, D.; Mathias, L.; Bedros, A.; Diamond, C.; Neff, A.; DiMichele, D.; Giardina, P.; Cohen, A.; Paidas, M.; Werner, E.; Matsunaga, A.; Tarantino, M.; Shafer, F.; Konkle, B.; Cuker, A.; Kouides, P.; Stein, D.

    2015-01-01

    Von Willebrand factor (VWF) contains binding sites for platelets and for vascular collagens to facilitate clot formation at sites of injury. Although previous work has shown that VWF can bind type IV collagen (collagen 4), little characterization of this interaction has been performed. We examined the binding of VWF to collagen 4 in vitro and extended this characterization to a murine model of defective VWF–collagen 4 interactions. The interactions of VWF and collagen 4 were further studied using plasma samples from a large study of both healthy controls and subjects with different types of von Willebrand disease (VWD). Our results show that collagen 4 appears to bind VWF exclusively via the VWF A1 domain, and that specific sequence variations identified through VWF patient samples and through site-directed mutagenesis in the VWF A1 domain can decrease or abrogate this interaction. In addition, VWF-dependent platelet binding to collagen 4 under flow conditions requires an intact VWF A1 domain. We observed that decreased binding to collagen 4 was associated with select VWF A1 domain sequence variations in type 1 and type 2M VWD. This suggests an additional mechanism through which VWF variants may alter hemostasis. PMID:25662333

  4. Widespread distribution and structural diversity of Type IV IRESs in members of Picornaviridae

    PubMed Central

    Asnani, Mukta; Kumar, Parimal; Hellen, Christopher U. T.

    2015-01-01

    Picornavirus genomes contain internal ribosomal entry sites (IRESs) that promote end-independent translation initiation. Five structural classes of picornavirus IRES have been identified, but numerous IRESs remain unclassified. Here, previously unrecognized Type IV IRESs were identified in members of three proposed picornavirus genera (Limnipivirus, Pasivirus, Rafivirus) and four recognized genera (Kobuvirus, Megrivirus, Sapelovirus, Parechovirus). These IRESs are ∼230–420 nucleotides long, reflecting heterogeneity outside a common structural core. Closer analysis yielded insights into evolutionary processes that have shaped contemporary IRESs. The presence of related IRESs in diverse genera supports the hypothesis that they are heritable genetic elements that spread by horizontal gene transfer. Recombination likely also accounts for the exchange of some peripheral subdomains, suggesting that IRES evolution involves incremental addition of elements to a pre-existing core. Nucleotide conservation is concentrated in ribosome-binding sites, and at the junction of helical domains, likely to ensure orientation of subdomains in an active conformation. PMID:25726971

  5. Hip resurfacing after iliofemoral distraction for type IV developmental dysplasia of the hip a case report.

    PubMed

    Sambri, A; Cadossi, M; Mazzotti, A; Faldini, C; Giannini, S

    2015-01-01

    Osteoarthritis secondary to developmental dysplasia of the hip is a surgical challenge because of the modified anatomy of the acetabulum which is deficient in its shape with poor bone quality, torsional deformities of the femur and the altered morphology of femoral head. Particularly in Crowe type III and IV, additional surgical challenges are present, such as limb-length discrepancy and adductor muscle contractures. This is a bilateral hip dysplasia case where bilateral hip replacement was indicated, on the left side with a resurfacing one and on the other side a two stage procedure using a iliofemoral external fixator to restore equal leg length with a lower risk of complications. This case report shows both the negative clinical outcome of the left and the excellent one of the right hip where the dysplasia was much more severe. Patient selection and implant positioning are crucial in determining long-term results. PMID:27218252

  6. Thompson and Hamilton type IV Freiberg's disease with involvement of multiple epiphyses of both feet.

    PubMed

    Lui, Tun Hing

    2015-01-01

    A 17-year-old boy reported left second and third toe pain after axial loading injury to his left foot. Radiographs showed collapse of the second metatarsal heads and epiphysial irregularities of the fifth metatarsal heads and the condyle of the proximal phalanx of the hallux of both feet. The patient was diagnosed to have Thompson and Hamilton type IV Freiberg's disease. He was screened for epiphysial dysplasia of the other sites. He had on and off bilateral hip and knee pain. Radiographs showed bilateral symmetrical epiphysial abnormalities with morphological change as focal concavity in bilateral femoral heads and fragmentation of the patellar articular surface with preservation of the patellofemoral joint space. PMID:25721826

  7. Type IV traffic ATPase TrwD as molecular target to inhibit bacterial conjugation.

    PubMed

    Ripoll-Rozada, Jorge; García-Cazorla, Yolanda; Getino, María; Machón, Cristina; Sanabria-Ríos, David; de la Cruz, Fernando; Cabezón, Elena; Arechaga, Ignacio

    2016-06-01

    Bacterial conjugation is the main mechanism responsible for the dissemination of antibiotic resistance genes. Hence, the search for specific conjugation inhibitors is paramount in the fight against the spread of these genes. In this pursuit, unsaturated fatty acids have been found to specifically inhibit bacterial conjugation. Despite the growing interest on these compounds, their mode of action and their specific target remain unknown. Here, we identified TrwD, a Type IV secretion traffic ATPase, as the molecular target for fatty acid-mediated inhibition of conjugation. Moreover, 2-alkynoic fatty acids, which are also potent inhibitors of bacterial conjugation, are also powerful inhibitors of the ATPase activity of TrwD. Characterization of the kinetic parameters of ATPase inhibition has led us to identify the catalytic mechanism by which fatty acids exert their activity. These results open a new avenue for the rational design of inhibitors of bacterial conjugation in the fight against the dissemination of antibiotic resistance genes. PMID:26915347

  8. New type IV pili-related genes involved in early stages of Ralstonia solanacearum potato infection.

    PubMed

    Siri, María Inés; Sanabria, Analía; Boucher, Christian; Pianzzola, María Julia

    2014-07-01

    This study provides insights into the pathogenesis of Ralstonia solanacearum, in particular with regards to strains belonging to phylotype IIB, sequevar 1 (IIB-1) and their interaction with potato, its natural host. We performed a comparative genomic analysis among IIB-1 R. solanacearum strains with different levels of virulence in order to identify candidate virulence genes. With this approach, we identified a 33.7-kb deletion in a strain showing reduced virulence on potato. This region contains a cluster of six genes putatively involved in type IV pili (Tfp) biogenesis. Functional analysis suggests that these proteins contribute to several Tfp-related functions such as twitching motility and biofilm formation. In addition, this genetic cluster was found to contribute to early bacterial wilt pathogenesis and colonization fitness of potato roots. PMID:24625029

  9. Type IV FDP avulsion: lessons learned clinically and through review of the literature.

    PubMed

    Henry, Steven L; Katz, Mark A; Green, David P

    2009-12-01

    The type IV flexor digitorum profundus avulsion is a rare injury involving fracture of the volar base of the distal phalanx and separation of the tendon from the fracture fragment. Recommendations for management are sparse and are substantiated only by a few isolated case reports. We recently encountered two of these injuries, both of which proved challenging, particularly with regard to joint incongruity and tendon adhesions. In reviewing the literature, it is apparent that no consensus exists regarding surgical strategies. However, based on our experience and that of other authors, we can suggest the following: (1) high index of suspicion of this potentially deceptive injury, with use of magnetic resonance imaging or ultrasound if preoperative confirmation is needed; (2) rigid bony fixation that prevents dorsal subluxation of the distal phalanx; (3) tendon repair that is independent of the bony fixation; and (4) early range of motion therapy. PMID:19399559

  10. Type IV pilus retraction in pathogenic Neisseria is regulated by the PilC proteins

    PubMed Central

    Morand, Philippe C; Bille, Emmanuelle; Morelle, Sandrine; Eugène, Emmanuel; Beretti, Jean-Luc; Wolfgang, Matthew; Meyer, Thomas F; Koomey, Michael; Nassif, Xavier

    2004-01-01

    Pathogenic Neisseria express type IV pili (tfp), which have been shown to play a central role in the interactions of bacteria with their environment. The regulation of piliation thus constitutes a central element in bacterial life cycle. The PilC proteins are outer membrane-associated proteins that have a key role in tfp biogenesis since PilC-null mutants appear defective for fibre expression. Moreover, tfp are also subjected to retraction, which is under the control of the PilT nucleotide-binding protein. In this work, we bring evidence that fibre retraction involves the translocation of pilin subunits to the cytoplasmic membrane. Furthermore, by engineering meningococcal strains that harbour inducible pilC genes, and with the use of meningococcus–cell interaction as a model for the sequential observation of fibre expression and retraction, we show that the PilC proteins regulate PilT-mediated fibre retraction. PMID:15103324

  11. A phage protein that inhibits the bacterial ATPase required for type IV pilus assembly.

    PubMed

    Chung, In-Young; Jang, Hye-Jeong; Bae, Hee-Won; Cho, You-Hee

    2014-08-01

    Type IV pili (TFPs) are required for bacterial twitching motility and for phage infection in the opportunistic human pathogen Pseudomonas aeruginosa. Here we describe a phage-encoded protein, D3112 protein gp05 (hereafter referred to as Tip, representing twitching inhibitory protein), whose expression is necessary and sufficient to mediate the inhibition of twitching motility. Tip interacts with and blocks the activity of bacterial-encoded PilB, the TFP assembly/extension ATPase, at an internal 40-aa region unique to PilB. Tip expression results in the loss of surface piliation. Based on these observations and the fact that many P. aeruginosa phages require TFPs for infection, Tip-mediated twitching inhibition may represent a generalized strategy for superinfection exclusion. Moreover, because TFPs are required for full virulence, PilB may be an attractive target for the development of novel antiinfectives. PMID:25049409

  12. Shipment and Disposal of Solidified Organic Waste (Waste Type IV) to the Waste Isolation Pilot Plant (WIPP)

    SciTech Connect

    D'Amico, E. L; Edmiston, D. R.; O'Leary, G. A.; Rivera, M. A.; Steward, D. M.

    2006-07-01

    In April of 2005, the last shipment of transuranic (TRU) waste from the Rocky Flats Environmental Technology Site to the WIPP was completed. With the completion of this shipment, all transuranic waste generated and stored at Rocky Flats was successfully removed from the site and shipped to and disposed of at the WIPP. Some of the last waste to be shipped and disposed of at the WIPP was waste consisting of solidified organic liquids that is identified as Waste Type IV in the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC) document. Waste Type IV waste typically has a composition, and associated characteristics, that make it significantly more difficult to ship and dispose of than other Waste Types, especially with respect to gas generation. This paper provides an overview of the experience gained at Rocky Flats for management, transportation and disposal of Type IV waste at WIPP, particularly with respect to gas generation testing. (authors)

  13. Neisseria meningitidis Type IV Pili Composed of Sequence Invariable Pilins Are Masked by Multisite Glycosylation.

    PubMed

    Gault, Joseph; Ferber, Mathias; Machata, Silke; Imhaus, Anne-Flore; Malosse, Christian; Charles-Orszag, Arthur; Millien, Corinne; Bouvier, Guillaume; Bardiaux, Benjamin; Péhau-Arnaudet, Gérard; Klinge, Kelly; Podglajen, Isabelle; Ploy, Marie Cécile; Seifert, H Steven; Nilges, Michael; Chamot-Rooke, Julia; Duménil, Guillaume

    2015-09-01

    The ability of pathogens to cause disease depends on their aptitude to escape the immune system. Type IV pili are extracellular filamentous virulence factors composed of pilin monomers and frequently expressed by bacterial pathogens. As such they are major targets for the host immune system. In the human pathogen Neisseria meningitidis, strains expressing class I pilins contain a genetic recombination system that promotes variation of the pilin sequence and is thought to aid immune escape. However, numerous hypervirulent clinical isolates express class II pilins that lack this property. This raises the question of how they evade immunity targeting type IV pili. As glycosylation is a possible source of antigenic variation it was investigated using top-down mass spectrometry to provide the highest molecular precision on the modified proteins. Unlike class I pilins that carry a single glycan, we found that class II pilins display up to 5 glycosylation sites per monomer on the pilus surface. Swapping of pilin class and genetic background shows that the pilin primary structure determines multisite glycosylation while the genetic background determines the nature of the glycans. Absence of glycosylation in class II pilins affects pilus biogenesis or enhances pilus-dependent aggregation in a strain specific fashion highlighting the extensive functional impact of multisite glycosylation. Finally, molecular modeling shows that glycans cover the surface of class II pilins and strongly decrease antibody access to the polypeptide chain. This strongly supports a model where strains expressing class II pilins evade the immune system by changing their sugar structure rather than pilin primary structure. Overall these results show that sequence invariable class II pilins are cloaked in glycans with extensive functional and immunological consequences. PMID:26367394

  14. A Decameter Stationary Type IV Burst in Imaging Observations on 2014 September 6

    NASA Astrophysics Data System (ADS)

    Koval, Artem; Stanislavsky, Aleksander; Chen, Yao; Feng, Shiwei; Konovalenko, Aleksander; Volvach, Yaroslav

    2016-08-01

    First-of-its-kind radio imaging of a decameter solar stationary type IV radio burst has been presented in this paper. On 2014 September 6 the observations of type IV burst radio emission were carried out with the two-dimensional heliograph based on the Ukrainian T-shaped radio telescope (UTR-2), together with other telescope arrays. Starting at ˜09:55 UT and for ˜3 hr, the radio emission was kept within the observational session of UTR-2. The interesting observation covered the full evolution of this burst, “from birth to death.” During the event lifetime, two C-class solar X-ray flares with peak times 11:29 UT and 12:24 UT took place. The time profile of this burst in radio has a double-humped shape that can be explained by injection of energetic electrons, accelerated by the two flares, into the burst source. According to the heliographic observations, we suggest that the burst source was confined within a high coronal loop, which was part of a relatively slow coronal mass ejection. The latter has been developed for several hours before the onset of the event. Through analysis of about 1.5 × 106 heliograms (3700 temporal frames with 4096 images in each frame that correspond to the number of frequency channels), the radio burst source imaging shows a fascinating dynamical evolution. Both space-based (GOES, SDO, SOHO, STEREO) data and various ground-based instrumentation (ORFEES, NDA, RSTO, NRH) records have been used for this study.

  15. Type IV Creep Damage Behavior in Gr.91 Steel Welded Joints

    NASA Astrophysics Data System (ADS)

    Hongo, Hiromichi; Tabuchi, Masaaki; Watanabe, Takashi

    2012-04-01

    Modified 9Cr-1Mo steel (ASME Grade 91 steel) is used as a key structural material for boiler components in ultra-supercritical (USC) thermal power plants at approximately 873 K (600 °C). The creep strength of welded joints of this steel decreases as a result of Type IV creep cracking that forms in the heat-affected zone (HAZ) under long-term use at high temperatures. The current article aims to elucidate the damage processes and microstructural degradations that take place in the HAZ of these welded joints. Long-term creep tests for base metal, simulated HAZ, and welded joints were conducted at 823 K, 873 K, and 923 K (550 °C, 600 °C, and 650 °C). Furthermore, creep tests of thick welded joint specimens were interrupted at several time steps at 873 K (600 °C) and 90 MPa, after which the distribution and evolution of creep damage inside the plates were measured quantitatively. It was found that creep voids are initiated in the early stages (0.2 of life) of creep rupture life, which coalesce to form a crack at a later stage (0.8 of life). In a fine-grained HAZ, creep damage is concentrated chiefly in an area approximately 20 pct below the surface of the plate. The experimental creep damage distributions coincide closely with the computed results obtained by damage mechanics analysis using the creep properties of a simulated fine-grained HAZ. Both the concentration of creep strain and the high multiaxial stress conditions in the fine-grained HAZ influence the distribution of Type IV creep damage.

  16. A Decameter Stationary Type IV Burst in Imaging Observations on 2014 September 6

    NASA Astrophysics Data System (ADS)

    Koval, Artem; Stanislavsky, Aleksander; Chen, Yao; Feng, Shiwei; Konovalenko, Aleksander; Volvach, Yaroslav

    2016-08-01

    First-of-its-kind radio imaging of a decameter solar stationary type IV radio burst has been presented in this paper. On 2014 September 6 the observations of type IV burst radio emission were carried out with the two-dimensional heliograph based on the Ukrainian T-shaped radio telescope (UTR-2), together with other telescope arrays. Starting at ∼09:55 UT and for ∼3 hr, the radio emission was kept within the observational session of UTR-2. The interesting observation covered the full evolution of this burst, “from birth to death.” During the event lifetime, two C-class solar X-ray flares with peak times 11:29 UT and 12:24 UT took place. The time profile of this burst in radio has a double-humped shape that can be explained by injection of energetic electrons, accelerated by the two flares, into the burst source. According to the heliographic observations, we suggest that the burst source was confined within a high coronal loop, which was part of a relatively slow coronal mass ejection. The latter has been developed for several hours before the onset of the event. Through analysis of about 1.5 × 106 heliograms (3700 temporal frames with 4096 images in each frame that correspond to the number of frequency channels), the radio burst source imaging shows a fascinating dynamical evolution. Both space-based (GOES, SDO, SOHO, STEREO) data and various ground-based instrumentation (ORFEES, NDA, RSTO, NRH) records have been used for this study.

  17. Expression of Cellulosome Components and Type IV Pili within the Extracellular Proteome of Ruminococcus flavefaciens 007

    PubMed Central

    Vodovnik, Maša; Duncan, Sylvia H.; Reid, Martin D.; Cantlay, Louise; Turner, Keith; Parkhill, Julian; Lamed, Raphael; Yeoman, Carl J.; Miller, Margret E. Berg.; White, Bryan A.; Bayer, Edward A.; Marinšek-Logar, Romana; Flint, Harry J.

    2013-01-01

    Background Ruminococcus flavefaciens is an important fibre-degrading bacterium found in the mammalian gut. Cellulolytic strains from the bovine rumen have been shown to produce complex cellulosome structures that are associated with the cell surface. R. flavefaciens 007 is a highly cellulolytic strain whose ability to degrade dewaxed cotton, but not Avicel cellulose, was lost following initial isolation in the variant 007S. The ability was recovered after serial subculture to give the cotton-degrading strain 007C. This has allowed us to investigate the factors required for degradation of this particularly recalcitrant form of cellulose. Methodology/Principal Findings The major proteins associated with the bacterial cell surface and with the culture supernatant were analyzed for R. flavefaciens 007S and 007C grown with cellobiose, xylan or Avicel cellulose as energy sources. Identification of the proteins was enabled by a draft genome sequence obtained for 007C. Among supernatant proteins a cellulosomal GH48 hydrolase, a rubrerthyrin-like protein and a protein with type IV pili N-terminal domain were the most strongly up-regulated in 007C cultures grown on Avicel compared with cellobiose. Strain 007S also showed substrate-related changes, but supernatant expression of the Pil protein and rubrerythrin in particular were markedly lower in 007S than in 007C during growth on Avicel. Conclusions/Significance This study provides new information on the extracellular proteome of R. flavefaciens and its regulation in response to different growth substrates. Furthermore it suggests that the cotton cellulose non-degrading strain (007S) has altered regulation of multiple proteins that may be required for breakdown of cotton cellulose. One of these, the type IV pilus was previously shown to play a role in adhesion to cellulose in R. albus, and a related pilin protein was identified here for the first time as a major extracellular protein in R. flavefaciens. PMID:23750253

  18. Neisseria meningitidis Type IV Pili Composed of Sequence Invariable Pilins Are Masked by Multisite Glycosylation

    PubMed Central

    Gault, Joseph; Ferber, Mathias; Machata, Silke; Imhaus, Anne-Flore; Malosse, Christian; Charles-Orszag, Arthur; Millien, Corinne; Bouvier, Guillaume; Bardiaux, Benjamin; Péhau-Arnaudet, Gérard; Klinge, Kelly; Podglajen, Isabelle; Ploy, Marie Cécile; Seifert, H. Steven; Nilges, Michael; Chamot-Rooke, Julia; Duménil, Guillaume

    2015-01-01

    The ability of pathogens to cause disease depends on their aptitude to escape the immune system. Type IV pili are extracellular filamentous virulence factors composed of pilin monomers and frequently expressed by bacterial pathogens. As such they are major targets for the host immune system. In the human pathogen Neisseria meningitidis, strains expressing class I pilins contain a genetic recombination system that promotes variation of the pilin sequence and is thought to aid immune escape. However, numerous hypervirulent clinical isolates express class II pilins that lack this property. This raises the question of how they evade immunity targeting type IV pili. As glycosylation is a possible source of antigenic variation it was investigated using top-down mass spectrometry to provide the highest molecular precision on the modified proteins. Unlike class I pilins that carry a single glycan, we found that class II pilins display up to 5 glycosylation sites per monomer on the pilus surface. Swapping of pilin class and genetic background shows that the pilin primary structure determines multisite glycosylation while the genetic background determines the nature of the glycans. Absence of glycosylation in class II pilins affects pilus biogenesis or enhances pilus-dependent aggregation in a strain specific fashion highlighting the extensive functional impact of multisite glycosylation. Finally, molecular modeling shows that glycans cover the surface of class II pilins and strongly decrease antibody access to the polypeptide chain. This strongly supports a model where strains expressing class II pilins evade the immune system by changing their sugar structure rather than pilin primary structure. Overall these results show that sequence invariable class II pilins are cloaked in glycans with extensive functional and immunological consequences. PMID:26367394

  19. Type IV collagen is an activating ligand for the adhesion G protein-coupled receptor GPR126.

    PubMed

    Paavola, Kevin J; Sidik, Harwin; Zuchero, J Bradley; Eckart, Michael; Talbot, William S

    2014-08-12

    GPR126 is an orphan heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptor (GPCR) that is essential for the development of diverse organs. We found that type IV collagen, a major constituent of the basement membrane, binds to Gpr126 and activates its signaling function. Type IV collagen stimulated the production of cyclic adenosine monophosphate in rodent Schwann cells, which require Gpr126 activity to differentiate, and in human embryonic kidney (HEK) 293 cells expressing exogenous Gpr126. Type IV collagen specifically bound to the extracellular amino-terminal region of Gpr126 containing the CUB (complement, Uegf, Bmp1) and pentraxin domains. Gpr126 derivatives lacking the entire amino-terminal region were constitutively active, suggesting that this region inhibits signaling and that ligand binding relieves this inhibition to stimulate receptor activity. A new zebrafish mutation that truncates Gpr126 after the CUB and pentraxin domains disrupted development of peripheral nerves and the inner ear. Thus, our findings identify type IV collagen as an activating ligand for GPR126, define its mechanism of activation, and highlight a previously unrecognized signaling function of type IV collagen in basement membranes. PMID:25118328

  20. Transcriptional activation by p53 of the human type IV collagenase (gelatinase A or matrix metalloproteinase 2) promoter.

    PubMed Central

    Bian, J; Sun, Y

    1997-01-01

    p53, a tumor suppressor and a transcription factor, has been shown to transcriptionally activate the expression of a number of important genes involved in the regulation of cell growth, DNA damage, angiogenesis, and apoptosis. In a computer search for other potential p53 target genes, we identified a perfect p53 binding site in the promoter of the human type IV collagenase (also called 72-kDa gelatinase or matrix metalloproteinase 2 [MMP-2]) gene. This p53 binding site was found to specifically bind to p53 protein in a gel shift assay. Transcription assays with luciferase reporters driven by the promoter or enhancer of the type IV collagenase gene revealed that (i) activation of the promoter activity is p53 binding site dependent in p53-positive cells but not in p53-negative cells and (ii) wild-type p53, but not p53 mutants commonly found in human cancers, transactivates luciferase expression driven by the type IV collagenase promoter as well as by a p53 site-containing enhancer element in the promoter. Significantly, expression of the endogenous type IV collagenase is also under the control of p53. Treatment of U2-OS cells, a wild-type p53-containing osteogenic sarcoma line, with a common p53 inducer, etoposide, induced p53 DNA binding and transactivation activities in a time-dependent manner. Induction of type IV collagenase expression followed the p53 activation pattern. No induction of type IV collagenase expression can be detected under the same experimental conditions in p53-negative Saos-2 cells. All these in vitro and in vivo assays strongly suggest that the type IV collagenase gene is a p53 target gene and that its expression is subject to p53 regulation. Our finding links p53 to a member of the MMP genes, a family of genes implicated in trophoblast implantation, wound healing, angiogenesis, arthritis, and tumor cell invasion. p53 may regulate these processes by upregulating expression of type IV collagenase. PMID:9343394

  1. Structural characterization of ribosome recruitment and translocation by type IV IRES

    PubMed Central

    Murray, Jason; Savva, Christos G; Shin, Byung-Sik; Dever, Thomas E; Ramakrishnan, V; Fernández, Israel S

    2016-01-01

    Viral mRNA sequences with a type IV IRES are able to initiate translation without any host initiation factors. Initial recruitment of the small ribosomal subunit as well as two translocation steps before the first peptidyl transfer are essential for the initiation of translation by these mRNAs. Using electron cryomicroscopy (cryo-EM) we have structurally characterized at high resolution how the Cricket Paralysis Virus Internal Ribosomal Entry Site (CrPV-IRES) binds the small ribosomal subunit (40S) and the translocation intermediate stabilized by elongation factor 2 (eEF2). The CrPV-IRES restricts the otherwise flexible 40S head to a conformation compatible with binding the large ribosomal subunit (60S). Once the 60S is recruited, the binary CrPV-IRES/80S complex oscillates between canonical and rotated states (Fernández et al., 2014; Koh et al., 2014), as seen for pre-translocation complexes with tRNAs. Elongation factor eEF2 with a GTP analog stabilizes the ribosome-IRES complex in a rotated state with an extra ~3 degrees of rotation. Key residues in domain IV of eEF2 interact with pseudoknot I (PKI) of the CrPV-IRES stabilizing it in a conformation reminiscent of a hybrid tRNA state. The structure explains how diphthamide, a eukaryotic and archaeal specific post-translational modification of a histidine residue of eEF2, is involved in translocation. DOI: http://dx.doi.org/10.7554/eLife.13567.001 PMID:27159451

  2. Agrobacterium VirB10 domain requirements for type IV secretion and T pilus biogenesis

    PubMed Central

    Jakubowski, Simon J.; Kerr, Jennifer E.; Garza, Isaac; Krishnamoorthy, Vidhya; Bayliss, Richard; Waksman, Gabriel; Christie, Peter J.

    2013-01-01

    Summary Agrobacterium tumefaciens VirB10 couples inner membrane (IM) ATP energy consumption to substrate transfer through the VirB/D4 type IV secretion (T4S) channel and also mediates biogenesis of the virB-encoded T pilus. Here, we determined the functional importance of VirB10 domains denoted as the: (i) N-terminal cytoplasmic region, (ii) transmembrane (TM) α-helix, (iii) proline-rich region (PRR) and (iv) C-terminal β-barrel domain. Mutations conferring a transfer- and pilus-minus (Tra−, Pil−) phenotype included PRR deletion and β-barrel substitution mutations that prevented VirB10 interaction with the outer membrane (OM) VirB7–VirB9 channel complex. Mutations permissive for substrate transfer but blocking pilus production (Tra+, Pil−) included a cytoplasmic domain deletion and TM domain insertion mutations. Another class of Tra+ mutations also selectively disrupted pilus biogenesis but caused release of pilin monomers to the milieu; these mutations included deletions of α-helical projections extending from the β-barrel domain. Our findings, together with results of Cys accessibility studies, indicate that VirB10 stably integrates into the IM, extends via its PRR across the periplasm, and interacts via its β-barrel domain with the VirB7–VirB9 channel complex. The data further support a model that distinct domains of VirB10 regulate formation of the secretion channel or the T pilus. PMID:19054325

  3. Positive Regulatory Domain I-Binding Factor 1 mediates repression of the MHC Class II Transactivator (CIITA) type IV promoter

    PubMed Central

    Chen, Han; Gilbert, Carolyn A.; Hudson, John A.; Bolick, Sophia C.; Wright, Kenneth L.; Piskurich, Janet F.

    2006-01-01

    MHC class II transactivator (CIITA), a co-activator that controls MHC class II (MHC II) transcription, functions as the master regulator of MHC II expression. Persistent activity of the CIITA type III promoter (pIII), one of the four potential promoters of this gene, is responsible for constitutive expression of MHC II by B lymphocytes. In addition, IFN-γ induces expression of CIITA in these cells through the type IV promoter (pIV). Positive regulatory domain 1-binding factor 1 (PRDI-BF1), called B lymphocyte-induced maturation protein 1 (Blimp-1) in mice, represses the expression of CIITA pIII in plasma and multiple myeloma cells. To investigate regulation of CIITA pIV expression by PRDI-BF1 in the B lymphocyte lineage, protein/DNA binding studies, and functional promoter analyses were performed. PRDI-BF1 bound to the IRF-E site in CIITA pIV. Ectopic expression of either PRDI-BF1 or Blimp-1 repressed this promoter in B lymphocytes. In vitro binding and functional analyses of CIITA pIV demonstrated that the IFN regulatory factor-element (IRF-E) is the target of this repression. In vivo genomic footprint analysis demonstrated protein binding at the IRF-E site of CIITA pIV in U266 myeloma cells, which express PRDI-BF1. PRDI-BF1β, a truncated form of PRDI-BF1 that is co-expressed in myeloma cells, also bound to the IRF-E site and repressed CIITA pIV. These findings demonstrate for the first time that, in addition to silencing expression of CIITA pIII in B lymphocytes, PRDI-BF1 is capable of binding and suppressing CIITA pIV. PMID:16765445

  4. AN ASSESSMENT OF THE SERVICE HISTORY AND CORROSION SUSCEPTIBILITY OF TYPE IV WASTE TANKS

    SciTech Connect

    Wiersma, B

    2008-09-18

    Type IV waste tanks were designed and built to store waste that does not require auxiliary cooling. Each Type IV tank is a single-shell tank constructed of a steel-lined pre-stressed concrete tank in the form of a vertical cylinder with a concrete domed roof. There are four such tanks in F-area, Tanks 17-20F, and four in H-Area, Tanks 21-24H. Leak sites were discovered in the liners for Tanks 19 and 20F in the 1980's. Although these leaks were visually observed, the investigation to determine the mechanism by which the leaks had occurred was not completed at that time. Therefore, a concern was raised that the same mechanism which caused the leak sites in the Tanks in F-area may also be operable in the H-Area tanks. Data from the construction of the tanks (i.e., certified mill test reports for the steel, no stress-relief), the service history (i.e., waste sample data, temperature data), laboratory tests on actual wastes and simulants (i.e., electrochemical testing), and the results of the visual inspections were reviewed. The following observations and conclusions were made: (1) Comparison of the compositional and microstructural features indicate that the A212 material utilized for construction of the H-Area tanks are far more resistant to SCC than the A285 materials used for construction of the F-Area tanks. (2) A review of the materials of construction, temperature history, service histories concluded that F-Area tanks likely failed by caustic stress corrosion cracking. (3) The environment in the F-Area tanks was more aggressive than that experienced by the H-Area tanks. (4) Based on a review of the service history, the H-Area tanks have not been exposed to an environment that would render the tanks susceptible to either nitrate stress corrosion cracking (i.e., the cause of failures in the Type I and II tanks) or caustic stress corrosion cracking. (5) Due to the very dilute and uninhibited solutions that have been stored in Tank 23H, vapor space corrosion has

  5. Community-Associated Methicillin-Resistant Staphylococcus aureus Clonal Complex 80 Type IV (CC80-MRSA-IV) Isolated from the Middle East: A Heterogeneous Expanding Clonal Lineage

    PubMed Central

    Harastani, Houda H.; Tokajian, Sima T.

    2014-01-01

    Background The emergence of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) has caused a change in MRSA epidemiology worldwide. In the Middle East, the persistent spread of CA-MRSA isolates that were associated with multilocus sequence type (MLST) clonal complex 80 and with staphylococcal cassette chromosome mec (SCCmec) type IV (CC80-MRSA-IV), calls for novel approaches for infection control that would limit its spread. Methodology/Principal Findings In this study, the epidemiology of CC80-MRSA-IV was investigated in Jordan and Lebanon retrospectively covering the period from 2000 to 2011. Ninety-four S. aureus isolates, 63 (67%) collected from Lebanon and 31 (33%) collected from Jordan were included in this study. More than half of the isolates (56%) were associated with skin and soft tissue infections (SSTIs), and 73 (78%) were Panton-Valentine Leukocidin (PVL) positive. Majority of the isolates (84%) carried the gene for exofoliative toxin d (etd), 19% had the Toxic Shock Syndrome Toxin-1 gene (tst), and seven isolates from Jordan had a rare combination being positive for both tst and PVL genes. spa typing showed the prevalence of type t044 (85%) and pulsed-field gel electrophoresis (PFGE) recognized 21 different patterns. Antimicrobial susceptibility testing showed the prevalence (36%) of a unique resistant profile, which included resistance to streptomycin, kanamycin, and fusidic acid (SKF profile). Conclusions The genetic diversity among the CC80 isolates observed in this study poses an additional challenge to infection control of CA-MRSA epidemics. CA-MRSA related to ST80 in the Middle East was distinguished in this study from the ones described in other countries. Genetic diversity observed, which may be due to mutations and differences in the antibiotic regimens between countries may have led to the development of heterogeneous strains. Hence, it is difficult to maintain “the European CA-MRSA clone” as a uniform clone and it

  6. Transforming growth factor-beta 1 stimulates glomerular mesangial cell synthesis of the 72-kd type IV collagenase.

    PubMed Central

    Marti, H. P.; Lee, L.; Kashgarian, M.; Lovett, D. H.

    1994-01-01

    Transforming growth factor-beta 1 (TGF-beta 1) is generally considered to exert positive effects on the accumulation of extracellular matrices. These occur as the net result of enhanced matrix protein synthesis, diminished matrix metalloproteinase (MMP) synthesis, and augmented production of specific inhibitors, including the tissue inhibitor of metalloproteinases (TIMP-1). Given that glomerular TGF-beta 1 synthesis is induced by inflammation, the effects of this cytokine on synthesis of the 72-kd type IV collagenase and TIMP-1 by cultured human mesangial cells were evaluated. Concentrations of TGF-beta 1 of 5 ng/ml and above specifically stimulated the synthesis of the 72-kd type IV collagenase. This effect was independent of the stimulatory effect of TGF-beta 1 on TIMP-1 synthesis, which was maximal in a lower concentration range (0.1 to 1 ng/ml). Most significantly, the net effect at the higher concentrations of TGF-beta 1 was an excess of enzyme over the TIMP-1 inhibitor. Northern blot analysis of TGF-beta 1-stimulated human mesangial cells demonstrated a specific increase in the abundance of the 3.1 kb mRNA transcript encoding the 72-kd type IV collagenase, presumably mediated by a direct stimulation of 72-kd type IV collagenase mRNA transcription observed as early as 3 hours after exposure to TGF-beta 1. These studies were extended to an analysis of the expression of TGF-beta 1 and 72-kd type IV collagenase mRNAs in normal and nephritic rats. In normal animals, basal TGF-beta 1 and 72-kd type IV collagenase mRNA expression was observed in a strictly mesangial distribution. After induction of acute immune complex-mediated glomerulonephritis, there was a major increase in TGF-beta 1 and 72-kd type IV collagenase mRNA expression, which was strictly limited to the expanded, hypercellular mesangial compartment. Enhanced synthesis of the mesangial type IV collagenase in response to TGF-beta 1 released during glomerular inflammatory processes could have an important

  7. Delay between the Circularly Polarized Components in Fine Structures during Solar Type IV Events

    NASA Astrophysics Data System (ADS)

    Chernov, G. P.; Zlobec, P.

    1995-08-01

    We analyzed intermediately polarized (20 80%) fine structures (pulsations, sudden reductions, fiber bursts and zebras) that were recorded in type IV events. The mean polarization degree was practically the same for all the fine structures recorded in an interval lasting a few minutes and it was similar to the polarization of the continuum. A detailed analysis during the evolution of single structures reveals changes in polarization (in particular an ‘undulation’ at flux density minima) even stronger than 20%. They were caused by a delay, up to 0.1 s, between the two circularly polarized components. The weaker polarimetric component was delayed in 2 sets and the stronger one in 1 set. In the event of April 24, 1985 different types of fine structures were sporadically detected in more than one hour long time interval. Short delays of the stronger or of the weaker component were sometimes observed. The events characterized by fine structures are generally totally polarized in the ordinary mode. We assume that this holds also for the phenomena studied here. The observed intermediate polarization therefore requires a depolarization due to propagation effects. We discuss the mode coupling and the reflection of the original radio signal that could also generate the delay of the weaker and the stronger component respectively. The possibility of polarization variation due to the change of the angle between the direction of the propagation and the magnetic field in a quasi-transversal region and in a low intensity magnetic field in a current sheet is also given.

  8. Neurologic, gastric, and opthalmologic pathologies in a murine model of mucolipidosis type IV.

    PubMed

    Venugopal, Bhuvarahamurthy; Browning, Marsha F; Curcio-Morelli, Cyntia; Varro, Andrea; Michaud, Norman; Nanthakumar, Nanda; Walkley, Steven U; Pickel, James; Slaugenhaupt, Susan A

    2007-11-01

    Mucolipidosis type IV (MLIV) is an autosomal recessive lysosomal storage disorder caused by mutations in the MCOLN1 gene, which encodes the 65-kDa protein mucolipin-1. The most common clinical features of patients with MLIV include severe mental retardation, delayed motor milestones, ophthalmologic abnormalities, constitutive achlorhydria, and elevated plasma gastrin levels. Here, we describe the first murine model for MLIV, which accurately replicates the phenotype of patients with MLIV. The Mcoln1(-/-) mice present with numerous dense inclusion bodies in all cell types in brain and particularly in neurons, elevated plasma gastrin, vacuolization in parietal cells, and retinal degeneration. Neurobehavioral assessments, including analysis of gait and clasping, confirm the presence of a neurological defect. Gait deficits progress to complete hind-limb paralysis and death at age ~8 mo. The Mcoln1(-/-) mice are born in Mendelian ratios, and both male and female Mcoln1(-/-) mice are fertile and can breed to produce progeny. The creation of the first murine model for human MLIV provides an excellent system for elucidating disease pathogenesis. In addition, this model provides an invaluable resource for testing treatment strategies and potential therapies aimed at preventing or ameliorating the abnormal lysosomal storage in this devastating neurological disorder. PMID:17924347

  9. Hereditary Sensory and Autonomic Neuropathy Type IV in 9 Year Old Boy: A Case Report

    PubMed Central

    AZADVARI, Mohaddeseh; EMAMI RAZAVI, Seyedeh Zahra; KAZEMI, Shahrbanoo

    2016-01-01

    Objective The Hereditary Sensory and Autonomic neuropathy (HSAN) is a rare group of neuropathies that affects the Sensory and Autonomic nervous system. The patients do not have the ability of sensing different sensations such as pain and temperature, which tends to lead to different injuries. In addition, due to autonomic involvement, the patients suffer from fluctuation in body temperature periodically and lack of precipitation. HSAN is divided into 5 types according to the age of onset, clinical features, and inheritance. Our case was a 9-yr old boy from cousin parents. He had some developmental delay and history of recurrent fever and convulsion in the first year of his life. Gradually, other symptoms added to patient’ feature such as multiple painless skin ulcers, tooth loss, destruction of toes and fingers. In electrodiagnostic study, we found decreased amplitude of sensory nerves, while the other studies were normal. Laboratory test and imaging studies were also normal. All clinical and paraclinical findings were in favor of HSAN type IV. There is no cure for such patients; as a result, these patients and their families need receiving appropriate education and timely rehabilitation services. PMID:27247588

  10. Altered stress fibers and integrin expression in the Malpighian epithelium of Drosophila type IV collagen mutants

    PubMed Central

    Kiss, András A.; Popovics, Nikoletta; Szabó, Gábor; Csiszár, Katalin; Mink, Mátyás

    2016-01-01

    Basement membranes (BMs) are highly specialized extracellular matrices (ECMs) that provide support and polarization cues for epithelial cells. Proper adhesion to the BM is pivotal in epithelial cell function and survival. Type IV collagens are the predominant components of all types of BMs, that form an irregular, polygonal lattice and serve as a scaffold for numerous other BM components and BM-associated cells. Mutations in the ubiquitous human BM components COL4A1 and COL4A2 cause a multisystem disorder involving nephropathy. Affected patients develop renal dysfunction and chronic kidney failure with or without hematuria. Mouse Col4a1 and Col4a2 mutants recapitulate the human symptoms. In vertebrates, excretion is accomplished by the kidneys and by the Malpighian tubules in insects, including the fruit fly Drosophila. Our present results with dominant, temperature-sensitive mutation of the Drosophila col4a1 gene demonstrate altered integrin expression and amplified effects of mechanical stress on the Malpighian epithelial cytoskeleton. PMID:27077087

  11. Hereditary Sensory and Autonomic Neuropathy Type IV in 9 Year Old Boy: A Case Report.

    PubMed

    Azadvari, Mohaddeseh; Emami Razavi, Seyedeh Zahra; Kazemi, Shahrbanoo

    2016-01-01

    Objective The Hereditary Sensory and Autonomic neuropathy (HSAN) is a rare group of neuropathies that affects the Sensory and Autonomic nervous system. The patients do not have the ability of sensing different sensations such as pain and temperature, which tends to lead to different injuries. In addition, due to autonomic involvement, the patients suffer from fluctuation in body temperature periodically and lack of precipitation. HSAN is divided into 5 types according to the age of onset, clinical features, and inheritance. Our case was a 9-yr old boy from cousin parents. He had some developmental delay and history of recurrent fever and convulsion in the first year of his life. Gradually, other symptoms added to patient' feature such as multiple painless skin ulcers, tooth loss, destruction of toes and fingers. In electrodiagnostic study, we found decreased amplitude of sensory nerves, while the other studies were normal. Laboratory test and imaging studies were also normal. All clinical and paraclinical findings were in favor of HSAN type IV. There is no cure for such patients; as a result, these patients and their families need receiving appropriate education and timely rehabilitation services. PMID:27247588

  12. Computational prediction of type III and IV secreted effectors in Gram-negative bacteria

    SciTech Connect

    McDermott, Jason E.; Corrigan, Abigail L.; Peterson, Elena S.; Oehmen, Christopher S.; Niemann, George; Cambronne, Eric; Sharp, Danna; Adkins, Joshua N.; Samudrala, Ram; Heffron, Fred

    2011-01-01

    In this review, we provide an overview of the methods employed by four recent papers that described novel methods for computational prediction of secreted effectors from type III and IV secretion systems in Gram-negative bacteria. The results of the studies in terms of performance at accurately predicting secreted effectors and similarities found between secretion signals that may reflect biologically relevant features for recognition. We discuss the web-based tools for secreted effector prediction described in these studies and announce the availability of our tool, the SIEVEserver (http://www.biopilot.org). Finally, we assess the accuracy of the three type III effector prediction methods on a small set of proteins not known prior to the development of these tools that we have recently discovered and validated using both experimental and computational approaches. Our comparison shows that all methods use similar approaches and, in general arrive at similar conclusions. We discuss the possibility of an order-dependent motif in the secretion signal, which was a point of disagreement in the studies. Our results show that there may be classes of effectors in which the signal has a loosely defined motif, and others in which secretion is dependent only on compositional biases. Computational prediction of secreted effectors from protein sequences represents an important step toward better understanding the interaction between pathogens and hosts.

  13. Xanthomonas citri subsp. citri type IV Pilus is required for twitching motility, biofilm development, and adherence.

    PubMed

    Dunger, German; Guzzo, Cristiane R; Andrade, Maxuel O; Jones, Jeffrey B; Farah, Chuck S

    2014-10-01

    Bacterial type IV pili (T4P) are long, flexible surface filaments that consist of helical polymers of mostly pilin subunits. Cycles of polymerization, attachment, and depolymerization mediate several pilus-dependent bacterial behaviors, including twitching motility, surface adhesion, pathogenicity, natural transformation, escape from immune system defense mechanisms, and biofilm formation. The Xanthomonas citri subsp. citri strain 306 genome codes for a large set of genes involved in T4P biogenesis and regulation and includes several pilin homologs. We show that X. citri subsp. citri can exhibit twitching motility in a manner similar to that observed in other bacteria such as Pseudomonas aeruginosa and Xylella fastidiosa and that this motility is abolished in Xanthomonas citri subsp. citri knockout strains in the genes coding for the major pilin subunit PilAXAC3241, the ATPases PilBXAC3239 and PilTXAC2924, and the T4P biogenesis regulators PilZXAC1133 and FimXXAC2398. Microscopy analyses were performed to compare patterns of bacterial migration in the wild-type and knockout strains and we observed that the formation of mushroom-like structures in X. citri subsp. citri biofilm requires a functional T4P. Finally, infection of X. citri subsp. citri cells by the bacteriophage (ΦXacm4-11 is T4P dependent. The results of this study improve our understanding of how T4P influence Xanthomonas motility, biofilm formation, and susceptibility to phage infection. PMID:25180689

  14. High-Force Generation Is a Conserved Property of Type IV Pilus Systems▿

    PubMed Central

    Clausen, Martin; Jakovljevic, Vladimir; Søgaard-Andersen, Lotte; Maier, Berenike

    2009-01-01

    The type IV pilus (T4P) system of Neisseria gonorrhoeae is the strongest linear molecular motor reported to date, but it is unclear whether high-force generation is conserved between bacterial species. Using laser tweezers, we found that the average stalling force of single-pilus retraction in Myxococcus xanthus of 149 ± 14 pN exceeds the force generated by N. gonorrhoeae. Retraction velocities including a bimodal distribution were similar between M. xanthus and N. gonorrhoeae, but force-dependent directional switching was not. Force generation by pilus retraction is energized by the ATPase PilT. Surprisingly, an M. xanthus mutant lacking PilT apparently still retracted T4P, although at a reduced frequency. The retraction velocity was comparable to the high-velocity mode in the wild type at low forces but decreased drastically when the force increased, with an average stalling force of 70 ± 10 pN. Thus, M. xanthus harbors at least two different retraction motors. Our results demonstrate that the major physical properties are conserved between bacteria that are phylogenetically distant and pursue very different lifestyles. PMID:19429611

  15. Altered stress fibers and integrin expression in the Malpighian epithelium of Drosophila type IV collagen mutants.

    PubMed

    Kiss, András A; Popovics, Nikoletta; Szabó, Gábor; Csiszár, Katalin; Mink, Mátyás

    2016-06-01

    Basement membranes (BMs) are highly specialized extracellular matrices (ECMs) that provide support and polarization cues for epithelial cells. Proper adhesion to the BM is pivotal in epithelial cell function and survival. Type IV collagens are the predominant components of all types of BMs, that form an irregular, polygonal lattice and serve as a scaffold for numerous other BM components and BM-associated cells. Mutations in the ubiquitous human BM components COL4A1 and COL4A2 cause a multisystem disorder involving nephropathy. Affected patients develop renal dysfunction and chronic kidney failure with or without hematuria. Mouse Col4a1 and Col4a2 mutants recapitulate the human symptoms. In vertebrates, excretion is accomplished by the kidneys and by the Malpighian tubules in insects, including the fruit fly Drosophila. Our present results with dominant, temperature-sensitive mutation of the Drosophila col4a1 gene demonstrate altered integrin expression and amplified effects of mechanical stress on the Malpighian epithelial cytoskeleton. PMID:27077087

  16. c-Type Cytochrome-Dependent Formation of U(IV) Nanoparticles by Shewanella oneidensis

    SciTech Connect

    Marshall, Matthew J.; Beliaev, Alex S.; Dohnalkova, Alice; Kennedy, David W.; Shi, Liang; Wang, Zheming; Boyanov, Maxim I.; Lai, Barry; Kemner, Kenneth M.; Mclean, Jeffrey S.; Reed, Samantha B.; Culley, David E.; Bailey, Vanessa L.; Simonson, Cody J.; Saffarini, Daad; Romine, Margaret F.; Zachara, John M.; Fredrickson, Jim K.

    2006-08-08

    Modern approaches for bioremediation of radionuclide contaminated environments are based on the ability of microorganisms to effectively catalyze changes in the oxidation states of metals that in turn influence their solubility. Although microbial metal reduction has been identified as an effective means for immobilizing highly-soluble uranium(VI) complexes in situ, the biomolecular mechanisms of U(VI) reduction are not well understood. Here, we show that c-type cytochromes of a dissimilatory metal reducing bacterium, Shewanella oneidensis MR-1 are essential for the reduction of U(VI) and formation of extracelluar UO2 nanoparticles. In particular, the outer membrane (OM) decaheme cytochrome MtrC, previously implicated in Mn(IV) and Fe(III) reduction, directly transferred electrons to U(VI). Additionally, deletions of mtrC and/or omcA significantly affected the in vivo U(VI) reduction rate relative to wild type MR-1. Similar to the wild type, the mutants accumulated UO2 nanoparticles extracellularly to high densities in association with an exopolymeric substance (EPS). In wild type cells, this UO2-EPS matrix exhibited glycocalyx-like properties, contained multiple elements of the OM, polysaccharide, and heme containing proteins. Using a novel combination of methods including synchrotron-based X-ray fluorescence microscopy and high resolution immune-electron microscopy, we demonstrate a close association of the extracellular UO2 nanoparticles with MtrC and OmcA. This is the first study to directly localize the OM-associated cytochromes with EPS, which contains biogenic UO2 nanoparticles. In the environment, such association of UO2 nanoparticles with biopolymers may exert a strong influence on subsequent behavior including susceptibility to oxidation by O2 or transport in soils and sediments.

  17. c-Type Cytochrome-Dependent Formation of U(IV) Nanoparticles by Shewanella oneidensis

    PubMed Central

    Marshall, Matthew J; Dohnalkova, Alice C; Kennedy, David W; Shi, Liang; Wang, Zheming; Boyanov, Maxim I; Lai, Barry; Kemner, Kenneth M; McLean, Jeffrey S; Reed, Samantha B; Culley, David E; Bailey, Vanessa L; Simonson, Cody J; Saffarini, Daad A; Romine, Margaret F; Zachara, John M

    2006-01-01

    Modern approaches for bioremediation of radionuclide contaminated environments are based on the ability of microorganisms to effectively catalyze changes in the oxidation states of metals that in turn influence their solubility. Although microbial metal reduction has been identified as an effective means for immobilizing highly-soluble uranium(VI) complexes in situ, the biomolecular mechanisms of U(VI) reduction are not well understood. Here, we show that c-type cytochromes of a dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1, are essential for the reduction of U(VI) and formation of extracelluar UO 2 nanoparticles. In particular, the outer membrane (OM) decaheme cytochrome MtrC (metal reduction), previously implicated in Mn(IV) and Fe(III) reduction, directly transferred electrons to U(VI). Additionally, deletions of mtrC and/or omcA significantly affected the in vivo U(VI) reduction rate relative to wild-type MR-1. Similar to the wild-type, the mutants accumulated UO 2 nanoparticles extracellularly to high densities in association with an extracellular polymeric substance (EPS). In wild-type cells, this UO 2-EPS matrix exhibited glycocalyx-like properties and contained multiple elements of the OM, polysaccharide, and heme-containing proteins. Using a novel combination of methods including synchrotron-based X-ray fluorescence microscopy and high-resolution immune-electron microscopy, we demonstrate a close association of the extracellular UO 2 nanoparticles with MtrC and OmcA (outer membrane cytochrome). This is the first study to our knowledge to directly localize the OM-associated cytochromes with EPS, which contains biogenic UO 2 nanoparticles. In the environment, such association of UO 2 nanoparticles with biopolymers may exert a strong influence on subsequent behavior including susceptibility to oxidation by O 2 or transport in soils and sediments. PMID:16875436

  18. ANOMALOUS SILICATE DUST EMISSION IN THE TYPE 1 LINER NUCLEUS OF M81

    SciTech Connect

    Smith, Howard A.; Ashby, M. L. N.; Fazio, G. G.; Huang, J.-S.; Marengo, M.; Wang, Z.; Willner, S.; Zezas, A.; Li, Aigen; Li, M. P.; Koehler, M.; Spinoglio, L.; Wu, Y. L. E-mail: lia@missouri.ed

    2010-06-10

    We report the detection and successful modeling of the unusual 9.7 {mu}m Si-O stretching silicate emission feature in the type 1 (i.e., face-on) LINER nucleus of M81. Using the Infrared Spectrograph (IRS) instrument on Spitzer, we determine the feature in the central 230 pc of M81 to be in strong emission, with a peak at {approx}10.5 {mu}m. This feature is strikingly different in character from the absorption feature of the galactic interstellar medium, and from the silicate absorption or weak emission features typical of galaxies with active star formation. We successfully model the high signal-to-noise ratio IRS spectra with porous silicate dust using laboratory-acquired mineral spectra. We find that the most probable fit uses micron-sized, porous grains of amorphous silicate and amorphous carbon. In addition to silicate dust, there is weak polycyclic aromatic hydrocarbon (PAH) emission present (particularly at 11.3 {mu}m, arising from the C-H out-of-plane bending vibration of relatively large PAHs of {approx}500-1000 C atoms) whose character reflects the low-excitation active galactic nucleus environment, with some evidence that small PAHs of {approx}100-200 C atoms (responsible for the 7.7 {mu}m C-C stretching band) in the immediate vicinity of the nucleus have been preferentially destroyed. Analysis of the infrared fine structure lines confirms the LINER character of the M81 nucleus. Four of the infrared H{sub 2} rotational lines are detected and fit to an excitation temperature of T {approx} 800 K. Spectral maps of the central 230 pc in the [Ne II] 12.8 {mu}m line, the H{sub 2} 17 {mu}m line, and the 11.3 {mu}m PAH C-H bending feature reveal arc- or spiral-like structures extending from the core. We also report on epochal photometric and spectroscopic observations of M81, whose nuclear intensity varies in time across the spectrum due to what is thought to be inefficient, sub-Eddington accretion onto its central black hole. We find that, contrary to the

  19. Relationship between serum and hepatic 7S fragments of type IV collagen in chronic liver disease.

    PubMed

    Suou, T; Yamada, S; Hosho, K; Yoshikawa, N; Kawasaki, H

    1996-05-01

    We evaluated the mechanism of increased serum concentrations of the 7S fragment of the N-terminal domain of type IV collagen (7S collagen) in chronic liver disease. We measured the concentrations of hepatic-free and deposited 7S collagens after extraction with Tris-HCl buffer and bacterial collagenase, then compared them with the serum levels in 8 normal controls and 48 patients with chronic liver disease. The hepatic 7S collagen levels extracted with Tris-HCl buffer and collagenase accounted for 7% and 93%, respectively, of the total 7S collagen levels in normal controls. Both hepatic 7S collagen levels as well as serum levels increased in accordance with the progress of liver disease. Serum levels of 7S collagen showed a closer correlation with the hepatic 7S collagen levels extracted with Tris-HCl buffer (r = .822), compared with those extracted with collagenase (r = .382). On the other hand, the histological degrees of liver fibrosis were highly correlated with the hepatic collagenase-extracted 7S collagen levels (r = .822), compared with serum and the hepatic Tris-HCl buffer-extracted levels (r = .478 and r = .537, respectively). Although there was no difference in serum and hepatic 7S collagen levels between B and C viral patients, the serum and hepatic Tris-HCl buffer-extracted 7S collagen levels were higher in patients with alcoholic cirrhosis than patients with viral cirrhosis. However, the hepatic collagenase-extracted levels were similar in both groups. Gel filtration demonstrated that the serum and hepatic Tris-HCl buffer-extracted 7S collagens were mainly eluted in the macromolecular 7S collagen-reactive fraction in cirrhosis, whereas the hepatic collagenase-extracted 7S collagen was eluted in the authentic 7S collagen-reactive fraction. The results suggest that serum 7S collagen levels are not a particularly reliable measure of hepatic fibrosis but reflect the enhanced metabolism, especially synthesis of type IV collagen in the liver. PMID:8621148

  20. Expression of CD26 and its association with dipeptidyl peptidase IV activity in lymphocytes of type 2 diabetes patients.

    PubMed

    Bellé, Luziane Potrich; Bitencourt, Paula Eliete Rodrigues; de Bona, Karine Santos; Zanette, Régis Adriel; Moresco, Rafael Noal; Moretto, Maria Beatriz

    2011-11-01

    Immune response and inflammation were suggested to play certain roles in the development and complications of type 2 diabetes mellitus. The main objective of this study was to investigate the CD26 expression and its relationship with adenosine deaminase (ADA), dipeptidyl peptidase IV (DPP-IV), γ-glutamyltransferase (GGT), and N-acetyl-β-glucosaminidase (NAG) activities in lymphocytes of type 2 diabetics (T2DM) patients. These parameters were assessed in 25 T2DM patients and 20 control subjects. We observed a decrease in CD26 expression and a significant increase in the ADA activity in T2DM patients when compared with control subjects. There were no differences between activities of DPP-IV, NAG, and GGT in lymphocytes of T2DM patients and control subjects. Meanwhile, a significant negative correlation was observed between CD26 expression and DPP-IV activity in lymphocytes of T2DM patients. Moreover, a positive correlation was found between DPPIV and ADA activities. The results suggest that the reduction of CD26 expression may be associated in the regulation of DPP-IV in T2DM patients. PMID:21614532

  1. Flexibility of bacterial type IV pili determined using atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Mogyoros, Josh; Lu, Shun; Harvey, Hanjeong; Burrows, Lori; Wickham, Robert; Dutcher, John

    Type IV pili (T4P) are very thin protein filaments extended and retracted from the surface of certain Gram-negative bacteria. Pili play a major role in processes such as adhesion, twitching motility and biofilm formation. We used atomic force microscopy (AFM) to perform force spectroscopy measurements on T4P of P. aeruginosa. Bacteria were adhered to the end of an AFM cantilever that was brought into contact with a substrate, allowing the pili to adhere. Force-separation curves were collected by retracting the cantilever, corresponding to the stretching of the T4P that was well described by the worm-like chain (WLC) model. Distinct peaks were observed in the distributions of the best-fit values of the persistence length Lp on two different surfaces, providing strong evidence for close-packed bundling of very flexible T4P. Surprisingly, the most prominent value of Lp ~ 1 nm is significantly less than the ~ 8 nm length of the PilA subunit. We have investigated this intriguing result by refining our protocol to combine AFM with fluorescence microscopy to isolate a single bacterium on a colloidal probe, as well as critically examining the applicability of the WLC model.

  2. Type IV Pilus Proteins Form an Integrated Structure Extending from the Cytoplasm to the Outer Membrane

    PubMed Central

    Li, Chengyun; Wallace, Regina A.; Black, Wesley P.; Li, Yue-zhong; Yang, Zhaomin

    2013-01-01

    The bacterial type IV pilus (T4P) is the strongest biological motor known to date as its retraction can generate forces well over 100 pN. Myxococcus xanthus, a δ-proteobacterium, provides a good model for T4P investigations because its social (S) gliding motility is powered by T4P. In this study, the interactions among M. xanthus T4P proteins were investigated using genetics and the yeast two-hybrid (Y2H) system. Our genetic analysis suggests that there is an integrated T4P structure that crosses the inner membrane (IM), periplasm and the outer membrane (OM). Moreover, this structure exists in the absence of the pilus filament. A systematic Y2H survey provided evidence for direct interactions among IM and OM proteins exposed to the periplasm. For example, the IM lipoprotein PilP interacted with its cognate OM protein PilQ. In addition, interactions among T4P proteins from the thermophile Thermus thermophilus were investigated by Y2H. The results indicated similar protein-protein interactions in the T4P system of this non-proteobacterium despite significant sequence divergence between T4P proteins in T. thermophilus and M. xanthus. The observations here support the model of an integrated T4P structure in the absence of a pilus in diverse bacterial species. PMID:23922942

  3. Inhibition of inflammasome activation by Coxiella burnetii type IV secretion system effector IcaA

    PubMed Central

    Cunha, Larissa D.; Ribeiro, Juliana M.; Fernandes, Talita D.; Massis, Liliana M.; Khoo, Chen Ai; Moffatt, Jennifer H.; Newton, Hayley J.; Roy, Craig R.; Zamboni, Dario S.

    2015-01-01

    Coxiella burnetii is a highly infectious bacterium that promotes its own replication in macrophages by inhibiting several host cell responses. Here, we show that C. burnetii inhibits caspase-1 activation in primary mouse macrophages. By using co-infection experiments, we determine that the infection of macrophages with C. burnetii inhibits the caspase-11-mediated non-canonical activation of the NLRP3 inflammasome induced by subsequent infection with Escherichia coli or Legionella pneumophila. Genetic screening using flagellin mutants of L. pneumophila as a surrogate host, reveals a novel C. burnetii gene (IcaA) involved in the inhibition of caspase activation. Expression of IcaA in L. pneumophila inhibited the caspase-11 activation in macrophages. Moreover, icaA- mutants of C. burnetii failed to suppress the caspase-11-mediated inflammasome activation induced by L. pneumophila. Our data reveal IcaA as a novel C. burnetii effector protein that is secreted by the Dot/Icm type IV secretion system and interferes with the caspase-11-induced, non-canonical activation of the inflammasome. PMID:26687278

  4. Stage IV intramucosal gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type.

    PubMed

    Ohtaka, Masahiko; Sato, Tadashi; Kobayashi, Shouji; Sueki, Ryouta; Yamaguchi, Tatsuya; Uetake, Tomoyoshi; Ohtsuka, Hiroyuki; Iwao, Noriaki; Kirito, Keita; Enomoto, Nobuyuki

    2013-04-01

    A 45-year-old woman with no symptoms underwent upper gastrointestinal endoscopy. A discolored area was noted at the greater curvature of the gastric upper body. Endoscopic ultrasonography demonstrated thickening of the second sonographic layer indicating that the depth of invasion was confined to the mucosa. A urea breath test and anti-Helicobacter pylori antibody test were negative. A computed tomography scan showed a consolidation at the right lung. Gastric biopsy and transbronchial lung biopsy (TBLB) demonstrated a monotonous proliferation of atypical small lymphocytes. A diagnosis of gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma) was made. The clinical stage was stage IV. A genetic analysis showed rearrangement of the joining region of the immunoglobulin heavy chain gene and identical clones in both lesions. An API2-MALT1 fusion gene was detected in the gastric lesion. After H. pylori eradication treatment, combination treatment with rituximab plus CHOP (R-CHOP) was performed; 6 months later an endoscopy revealed complete disappearance of the lesion. Multiple gastric biopsies showed no infiltrating atypical lymphocytes. Similarly, the lesion in the lung showed complete remission (CR) on CT and TBLB. This report shows that a gastric MALT lymphoma located in the mucosa and disseminated to the lung maintained CR by R-CHOP. PMID:26181449

  5. N. elongata produces type IV pili that mediate interspecies gene transfer with N. gonorrhoeae.

    PubMed

    Higashi, Dustin L; Biais, Nicolas; Weyand, Nathan J; Agellon, Al; Sisko, Jennifer L; Brown, Lewis M; So, Magdalene

    2011-01-01

    The genus Neisseria contains at least eight commensal and two pathogenic species. According to the Neisseria phylogenetic tree, commensals are basal to the pathogens. N. elongata, which is at the opposite end of the tree from N. gonorrhoeae, has been observed to be fimbriated, and these fimbriae are correlated with genetic competence in this organism. We tested the hypothesis that the fimbriae of N. elongata are Type IV pili (Tfp), and that Tfp functions in genetic competence. We provide evidence that the N. elongata fimbriae are indeed Tfp. Tfp, as well as the DNA Uptake Sequence (DUS), greatly enhance N. elongata DNA transformation. Tfp allows N. elongata to make intimate contact with N. gonorrhoeae and to mediate the transfer of antibiotic resistance markers between these two species. We conclude that Tfp functional for genetic competence is a trait of a commensal member of the Neisseria genus. Our findings provide a mechanism for the horizontal gene transfer that has been observed among Neisseria species. PMID:21731720

  6. Force-dependent polymorphism in type IV pili reveals hidden epitopes.

    PubMed

    Biais, Nicolas; Higashi, Dustin L; Brujic, Jasna; So, Magdalene; Sheetz, Michael P

    2010-06-22

    Through evolution, nature has produced exquisite nanometric structures, with features unrealized in the most advanced man-made devices. Type IV pili (Tfp) represent such a structure: 6-nm-wide retractable filamentous appendages found in many bacteria, including human pathogens. Whereas the structure of Neisseria gonorrhoeae Tfp has been defined by conventional structural techniques, it remains difficult to explain the wide spectrum of functions associated with Tfp. Here we uncover a previously undescribed force-induced quaternary structure of the N. gonorrhoeae Tfp. By using a combination of optical and magnetic tweezers, atomic force microscopy, and molecular combing to apply forces on purified Tfp, we demonstrate that Tfp subjected to approximately 100 pN of force will transition into a new conformation. The new structure is roughly 3 times longer and 40% narrower than the original structure. Upon release of the force, the Tfp fiber regains its original form, indicating a reversible transition. Equally important, we show that the force-induced conformation exposes hidden epitopes previously buried in the Tfp fiber. We postulate that this transition provides a means for N. gonorrhoeae to maintain attachment to its host while withstanding intermittent forces encountered in the environment. Our findings demonstrate the need to reassess our understanding of Tfp dynamics and functions. They could also explain the structural diversity of other helical polymers while presenting a unique mechanism for polymer elongation and exemplifying the extreme structural plasticity of biological polymers. PMID:20534431

  7. Genes Required for Assembly of Pili Associated with the Helicobacter pylori cag Type IV Secretion System

    PubMed Central

    Johnson, Elizabeth M.; Gaddy, Jennifer A.; Voss, Bradley J.; Hennig, Ewa E.

    2014-01-01

    Helicobacter pylori causes numerous alterations in gastric epithelial cells through processes that are dependent on activity of the cag type IV secretion system (T4SS). Filamentous structures termed “pili” have been visualized at the interface between H. pylori and gastric epithelial cells, and previous studies suggested that pilus formation is dependent on the presence of the cag pathogenicity island (PAI). Thus far, there has been relatively little effort to identify specific genes that are required for pilus formation, and the role of pili in T4SS function is unclear. In this study, we selected 7 genes in the cag PAI that are known to be required for T4SS function and investigated whether these genes were required for pilus formation. cagT, cagX, cagV, cagM, and cag3 mutants were defective in both T4SS function and pilus formation; complemented mutants regained T4SS function and the capacity for pilus formation. cagY and cagC mutants were defective in T4SS function but retained the capacity for pilus formation. These results define a set of cag PAI genes that are required for both pilus biogenesis and T4SS function and reveal that these processes can be uncoupled in specific mutant strains. PMID:24891108

  8. Cag Type IV Secretion System: CagI Independent Bacterial Surface Localization of CagA

    PubMed Central

    Kumar, Navin; Shariq, Mohd; Kumari, Rajesh; Tyagi, Rakesh K.; Mukhopadhyay, Gauranga

    2013-01-01

    Helicobacter pylori Cag type IV secretion system (Cag-T4SS) is a multi-component transporter of oncoprotein CagA across the bacterial membranes into the host epithelial cells. To understand the role of unique Cag-T4SS component CagI in CagA translocation, we have characterized it by biochemical and microscopic approaches. We observed that CagI is a predominantly membrane attached periplasmic protein partially exposed to the bacterial surface especially on the pili. The association of the protein with membrane appeared to be loose as it could be easily recovered in soluble fraction. We documented that the stability of the protein is dependent on several key components of the secretion system and it has multiple interacting partners including a non-cag-PAI protein HP1489. Translocation of CagA across the bacterial membranes to cell surface is CagI-independent process. The observations made herein are expected to assist in providing an insight into the substrate translocation by the Cag-T4SS system and Helicobacter pylori pathogenesis. PMID:24040297

  9. Theoretical studies of organotin(IV) complexes derived from ONO-donor type schiff base ligands.

    PubMed

    Şirikci, Gökhan; Ancın, Nilgün Ataünal; Öztaş, Selma Gül

    2015-09-01

    In this work a molecular modeling study was carried out based on a series of organotin(IV) derivatives which were complexed with ONO-Donor type Schiff base ligands to build up a statistical data pool for researchers. For this purpose, various properties of the selected complexes such as energies, band gaps, chemical reactivity descriptors, polarizabilities, geometric parameters, (1)H-NMR, (13)C-NMR chemical shifting values were obtained through density functional theory using B3LYP, CAM-B3LYP, TPSSTPSS, TPSSh, HCTH, wB97XD, and MN12SX functionals. Empirical dispersion corrections were incorporated for some functionals and solvent effects were also taken into account through applying polarizable continuum model (PCM). (1)H-NMR, (13)C-NMR chemical shifts were calculated via linear regression analysis using either gauge invariant atomic orbital (GIAO) or continuous set of gauge transformations (CSGT) methods. While structural properties were being explored, quantitative effects of utilized functionals and empirical dispersion corrections over calculated properties were shown in detail. PMID:26245450

  10. Cyclic Di-GMP Riboswitch-Regulated Type IV Pili Contribute to Aggregation of Clostridium difficile

    PubMed Central

    Bordeleau, Eric; Purcell, Erin B.; Lafontaine, Daniel A.; Fortier, Louis-Charles; Tamayo, Rita

    2014-01-01

    Clostridium difficile is an anaerobic Gram-positive bacterium that causes intestinal infections with symptoms ranging from mild diarrhea to fulminant colitis. Cyclic diguanosine monophosphate (c-di-GMP) is a bacterial second messenger that typically regulates the switch from motile, free-living to sessile and multicellular behaviors in Gram-negative bacteria. Increased intracellular c-di-GMP concentration in C. difficile was recently shown to reduce flagellar motility and to increase cell aggregation. In this work, we investigated the role of the primary type IV pilus (T4P) locus in c-di-GMP-dependent cell aggregation. Inactivation of two T4P genes, pilA1 (CD3513) and pilB1 (CD3512), abolished pilus formation and significantly reduced cell aggregation under high c-di-GMP conditions. pilA1 is preceded by a putative c-di-GMP riboswitch, predicted to be transcriptionally active upon c-di-GMP binding. Consistent with our prediction, high intracellular c-di-GMP concentration increased transcript levels of T4P genes. In addition, single-round in vitro transcription assays confirmed that transcription downstream of the predicted transcription terminator was dose dependent and specific to c-di-GMP binding to the riboswitch aptamer. These results support a model in which T4P gene transcription is upregulated by c-di-GMP as a result of its binding to an upstream transcriptionally activating riboswitch, promoting cell aggregation in C. difficile. PMID:25512308

  11. Preparation and characterization of resistant starch type IV nanoparticles through ultrasonication and miniemulsion cross-linking.

    PubMed

    Ding, Yongbo; Zheng, Jiong; Xia, Xuejuan; Ren, Tingyuan; Kan, Jianquan

    2016-05-01

    This study aimed to assess the properties of resistant starch type IV (chemically modified starch, RS4) prepared from a new and convenient synthesis route by using ultrasonication combined with water-in-oil miniemulsion cross-linking technique. A three-factor Box-Behnken design and optimization was used to minimize particle size through the developed RS4 nanoparticles. The predicted minimized Z-Avel (576.1nm) under the optimum conditions of the process variables (ultrasonic power, 214.57W; sonication time, 114.73min; and oil/water ratio, 10.54:1) was very close to the experimental value (651.0nm) determined in a batch experiment. After preparing the RS4 nanoparticles, morphological, physical, chemical, and functional properties were assessed. Results revealed that RS4 nanoparticle size reached about 600nm. Scanning electron microscopy images showed that ultrasonication induced notches and grooves on the surface. Under polarized light, the polarized cross was impaired. X-ray diffraction results revealed that the crystalline structure was disrupted. Smaller or no endotherms were exhibited in DSC analysis. In the FTIR graph, new peaks at 1532.91 and 1451.50cm(-1) were observed, and pasting properties were reduced. Amylose content, solubility, and SP increased, but RS content decreased. Anti-digestibility remained after ultrasonication. The prepared RS4 nanoparticles could be extensively used in biomedical applications and in the development of new medical materials. PMID:26877007

  12. Mechanism and function of type IV secretion during infection of the human host

    PubMed Central

    Gonzalez-Rivera, Christian; Bhatty, Minny; Christie, Peter J.

    2015-01-01

    Bacterial pathogens employ type IV secretion systems (T4SSs) for various purposes to aid in survival and proliferation in eukaryotic host. One large T4SS subfamily, the conjugation systems, confers a selective advantage to the invading pathogen in clinical settings through dissemination of antibiotic resistance genes and virulence traits. Besides their intrinsic importance as principle contributors to the emergence of multiply drug-resistant ‘superbugs’, detailed studies of these highly tractable systems have generated important new insights into the mode of action and architectures of paradigmatic T4SSs as a foundation for future efforts aimed at suppressing T4SS machine function. Over the past decade, extensive work on the second large T4SS subfamily, the effector translocators, has identified a myriad of mechanisms employed by pathogens to subvert, subdue, or bypass cellular processes and signaling pathways of the host cell. An overarching theme in the evolution of many effectors is that of molecular mimicry. These effectors carry domains similar to those of eukaryotic proteins and exert their effects through stealthy interdigitation of cellular pathways, often with the outcome not of inducing irreversible cell damage but rather of reversibly modulating cellular functions. This chapter summarizes the major developments for the actively studied pathogens with an emphasis on the structural and functional diversity of the T4SSs and the emerging common themes surrounding effector function in the human host. PMID:27337453

  13. Late onset pityriasis rubra pilaris type IV treated with low-dose acitretin.

    PubMed

    Mota, Fernando; Carvalho, Sandrina; Sanches, Madalena; Selores, Manuela

    2016-01-01

    Pityriasis rubra pilaris is a chronic inflammatory dermatosis of unknown etiology and great clinical variability. It has been divided into six categories. Types III, IV, and V occur in childhood and are distinguished by their clinical presentation, age of onset, and course. We report a 19-year-old male patient with a 2-week history of pruritic, scaling dermatosis of the hands, feet, elbows, and knees. He had no family history of skin disease. On physical examination, we observed circumscribed, reddish-orange, scaling plaques affecting the elbows and knees and a waxy palmoplantar keratoderma. The skin biopsy showed acanthosis, alternating orthokeratosis, parakeratosis, and follicular plugging suggestive of pityriasis rubra pilaris. The patient started treatment with oral acitretin, 25 mg every other day. The treatment was tolerated well, and after 6 months the lesions had resolved completely. Pityriasis rubra pilaris is a chronic papulosquamous disorder of unknown pathogenesis, characterized by reddish-orange scaly plaques, palmoplantar keratoderma, and keratotic follicular papules. There is still no consensus regarding the treatment, but therapeutic options include systemic retinoids, particularly acitretin in the recommended dose of 0.5 to 0.75 mg/kg/day. In our case, the patient was treated with a low-dose regimen of acitretin, which was effective and well tolerated. PMID:27014774

  14. Transthoracic Collis-Nissen repair for massive type IV paraesophageal hernia.

    PubMed

    Itano, Hideki; Okamoto, Shiroh; Kodama, Kanji; Horita, Naokatsu

    2008-09-01

    An 80-year-old woman presented with type IV massive hiatal hernia with intrathoracic upside-down stomach and transverse colon. She was dyspneic and vomited upon consuming food or water. Consequently, she developed aspiration pneumonia. Both esophagoscopy and upper gastrointestinal series demonstrated significant cephalad displacement of the gastroesophageal junction. A Collis-Nissen hernial repair by muscle-sparing mini-thoracotomy was performed successfully. To date, 3 years after surgery, the patient is enjoying normal oral intake, has an excellent activities of daily living level, and there is no hernia recurrence. Cases of massive paraesophageal hernia are frequently associated with esophageal shortening that causes tension on the repairs and late failure. Advantages of the transthoracic approach in such cases include feasibility of direct esophageal mobilization, accurate assessment of esophageal tension, and facilitation of Collis gastroplasty. The true indication for transthoracic Collis-Nissen repair among cases of paraesophageal hiatal hernia with a short esophagus should be acknowledged more in the era of laparoscopy. PMID:18791669

  15. Outside-In Assembly Pathway of the Type IV Pilus System in Myxococcus xanthus

    PubMed Central

    Friedrich, Carmen; Bulyha, Iryna

    2014-01-01

    Type IV pili (T4P) are ubiquitous bacterial cell surface structures that undergo cycles of extension, adhesion, and retraction. T4P function depends on a highly conserved envelope-spanning macromolecular machinery consisting of 10 proteins that localizes polarly in Myxococcus xanthus. Using this localization, we investigated the entire T4P machinery assembly pathway by systematically profiling the stability of all and the localization of eight of these proteins in the absence of other T4P machinery proteins as well as by mapping direct protein-protein interactions. Our experiments uncovered a sequential, outside-in pathway starting with the outer membrane (OM) PilQ secretin ring. PilQ recruits a subcomplex consisting of the inner membrane (IM) lipoprotein PilP and the integral IM proteins PilN and PilO by direct interaction with the periplasmic domain of PilP. The PilP/PilN/PilO subcomplex recruits the cytoplasmic PilM protein, by direct interaction between PilN and PilM, and the integral IM protein PilC. The PilB/PilT ATPases that power extension/retraction localize independently of other T4P machinery proteins. Thus, assembly of the T4P machinery initiates with formation of the OM secretin ring and continues inwards over the periplasm and IM to the cytoplasm. PMID:24187092

  16. Frequency Dependence of Polarization of Zebra Pattern in Type-IV Solar Radio Bursts

    NASA Astrophysics Data System (ADS)

    Kaneda, Kazutaka; Misawa, H.; Iwai, K.; Tsuchiya, F.; Obara, T.

    2015-08-01

    We investigated the polarization characteristics of a zebra pattern (ZP) in a type-IV solar radio burst observed with AMATERAS on 2011 June 21 for the purpose of evaluating the generation processes of ZPs. Analyzing highly resolved spectral and polarization data revealed the frequency dependence of the degree of circular polarization and the delay between two polarized components for the first time. The degree of circular polarization was 50%-70% right-handed and it varied little as a function of frequency. Cross-correlation analysis determined that the left-handed circularly polarized component was delayed by 50-70 ms relative to the right-handed component over the entire frequency range of the ZP and this delay increased with the frequency. We examined the obtained polarization characteristics by using pre-existing ZP models and concluded that the ZP was generated by the double-plasma-resonance process. Our results suggest that the ZP emission was originally generated in a completely polarized state in the O-mode and was partly converted into the X-mode near the source. Subsequently, the difference between the group velocities of the O-mode and X-mode caused the temporal delay.

  17. Molecular organization of type IV collagen: polymer liquid crystal-like aspects.

    PubMed

    Gathercole, L J; Barnard, K; Atkins, E D

    1989-12-01

    A new X-ray diffraction pattern from type IV collagen is described, which can be interpreted on the basis of crystalline and liquid crystalline origins of the reflections. Bovine anterior lens capsules extracted with 1 M NaCl and oriented by extension of 60% under constant load gave medium angle X-ray diffraction patterns showing many of the characteristics typical of liquid crystals. Prominent features, apart from those wide angle features attributable to the collagen triple helix, are (1) a four-point pattern of broad reflections at d-spacing 3.9 nm, and layer line spacing near 5 nm. (2) A broad intense equatorial peak centred at 1.24 nm, indicative of liquid-like lateral molecular associations. (3) A set of five sharp, streaked meridional reflections (previously obscured by the broad peak near 5 nm in unextracted capsules). (4) A further six higher angle reflections of a diffuse, arced and broad appearance on the meridian. The sharp streaked meridional reflections emanate from a long-range periodicity of units 8-9 nm in diameter. These features form a self-consistent system if interpreted on the basis of a staggered liquid crystal-like array of collagen molecules, in which case the first five meridionals and remaining broad reflections, sampled on the meridian, can all be indexed as orders of 21 nm. PMID:2489101

  18. Ehlers-Danlos syndrome type IV is associated with a novel G984R COL3A1 mutation.

    PubMed

    Deng, Yao; Wei, Shijie; Hu, Shijun; Chen, Jinlan; Tan, Zhiping; Yang, Yifeng

    2015-07-01

    Ehlers-Danlos syndrome type IV is an autosomal dominant connective tissue disease. Mutations in COL3A1 have been identified to underlie this disease; however, to the best of our knowledge, no COL3A1 mutations have been reported in Ehlers-Danlos syndrome type IV patients with an ascending aortic aneurysm. In order to develop further understanding of COL3A1 mutations, an Ehlers-Danlos syndrome type IV patient diagnosed with an ascending aortic aneurysm and a familial history of sudden mortality was analyzed. Genomic DNA was isolated from the peripheral blood of the patient and his family members. All coding exons of eight aneurysm-related genes (FBN1, TGFBR1, TGFBR 2, MYH11, ACTA2, SLC2A10, NOTCH1 and COL3A1) were amplified using polymerase chain reaction (PCR). The PCR products were sequenced with the ABI 3100 Genetic Analyzer, and a mutation was predicted and identified using Polyphen-2, SIFT and Mutation Taster. The novel mutation was identified as c.2950G>A in COL3A1, which results in p.G984R. All three programs predicted this mutation to be deleterous to the protein function. The novel mutation identified in this study is potentially responsible for Ehlers-Danlos syndrome type IV in this patient, and expands the spectrum of COL3A1 mutations. PMID:25776230

  19. Aggressive change of a carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV.

    PubMed

    Kojima, Atsuhiro; Saga, Isako; Tomio, Ryosuke; Kosho, Tomoki; Hatamochi, Atsushi

    2015-06-01

    The authors report a rare case of a carotid-cavernous fistula (CCF) secondary to Ehlers-Danlos syndrome (EDS) type IV which showed an aggressive angiographical change.A 59-year-old woman presented with headache, right pulsatile tinnitus, and diplopia on the right side. The diagnostic angiography demonstrated a right CCF. Accordingly transarterial embolization of the fistula was attempted 5 days later. The initial right internal carotid angiography showed an aneurysm on the petrous portion of the internal carotid artery (ICA) which was not recognized in the diagnostic angiography. Spontaneous reduction of the shunt flow and long dissection of the ICA were also revealed. The aneurysm was successfully occluded with coils, and only minor shunt flow was shown on the final angiogram. EDS type IV was diagnosed with a skin biopsy for a collagen abnormality. After the operation, the stenosis of the right ICA gradually progressed, although there was no recurrence of the CCF.Interventional treatment for patients with EDS can cause devastating vascular complication. We should be aware of the possibility of EDS type IV when a spontaneous CCF shows unusual angiographical change because early diagnosis of EDS type IV is crucial for determination of the optimum treatment option. PMID:26015525

  20. [Mucopolysaccharidosis. A case report of Morquio's type-A disease (MPS IV-A)].

    PubMed

    Pagni, L; Bartolozzi, L; Giacchetti, D

    1992-11-01

    The mucopolysaccharidosis represent a broad spectrum of disorders due to the deficiency of one of a group of enzymes which degrade three classes of mucopolysaccharides: heparan sulfate, dermatan-sulfate and keratan sulfate. The general phenotype includes coarse facies, corneal clouding, hepatosplenomegaly, joint stiffness, hernias, dysostosis multiplex, mucopolysaccharides excretion in the urine and metachromatic staining in peripheral leukocytes and bone marrow. Various components of the MPS phenotype are also found in the mucolipidoses, glycoprotein storage diseases. Detailed clinical and radiologic evaluation and identification of the type of MPS excreted in the urine help to narrow the diagnosis possibilities. Definitive diagnosis requires assay of specific enzymes in various tissues such as cultured skin fibroblasts. For the moment there are 14 types of known mucopolysaccharidoses, including several subtypes. They are classified into Hurler's syndrome (MPS I-H); Scheie's syndrome (MPS I-S); Hurler-Scheie's syndrome (MPS I-H/S); Hunter's syndrome A, B (MPS II-A, B); Sanfilippo's syndrome A,B,C,D (MPS II-A,B,C,D); Morquio's syndrome A,B,C (MSP IV-A,B,C); Maroteaux-Lamy's syndrome (MPS VI) and Sly's syndrome MPS VII). The mucopolysaccharidosis incidence is around 0.04-0.3% of the newborn and they are 1.5% of all congenital disorders. All mucopolysaccharidosis are autosomal recessive disorders, except for Hunter's syndrome that is X-linked and recessive. Patient suffering of MPS, usually, don't show clinical sign from their birth in fact they develop later their characteristics. The average surviving of this patients is around 20-30 years old, and the exitus is due to cardiac failure or to infections to the gastrointestinal tract or to instability of atlantoaxial joint.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1294876

  1. Pseudomonas aeruginosa d-Arabinofuranose Biosynthetic Pathway and Its Role in Type IV Pilus Assembly*

    PubMed Central

    Harvey, Hanjeong; Kus, Julianne V.; Tessier, Luc; Kelly, John; Burrows, Lori L.

    2011-01-01

    Pseudomonas aeruginosa strains PA7 and Pa5196 glycosylate their type IVa pilins with α1,5-linked d-arabinofuranose (d-Araf), a rare sugar configuration identical to that found in cell wall polymers of the Corynebacterineae. Despite this chemical identity, the pathway for biosynthesis of α1,5-d-Araf in Gram-negative bacteria is unknown. Bioinformatics analyses pointed to a cluster of seven P. aeruginosa genes, including homologues of the Mycobacterium tuberculosis genes Rv3806c, Rv3790, and Rv3791, required for synthesis of a polyprenyl-linked d-ribose precursor and its epimerization to d-Araf. Pa5196 mutants lacking the orthologues of those genes had non-arabinosylated pilins, poor twitching motility, and significantly fewer surface pili than the wild type even in a retraction-deficient (pilT) background. The Pa5196 pilus system assembled heterologous non-glycosylated pilins efficiently, demonstrating that it does not require post-translationally modified subunits. Together the data suggest that pilins of group IV strains need to be glycosylated for productive subunit-subunit interactions. A recombinant P. aeruginosa PAO1 strain co-expressing the genes for d-Araf biosynthesis, the pilin modification enzyme TfpW, and the acceptor PilAIV produced arabinosylated pili, confirming that the Pa5196 genes identified are both necessary and sufficient. A P. aeruginosa epimerase knock-out could be complemented with the corresponding Mycobacterium smegmatis gene, demonstrating conservation between the systems of the Corynebacterineae and Pseudomonas. This work describes a novel Gram-negative pathway for biosynthesis of d-Araf, a key therapeutic target in Corynebacterineae. PMID:21676874

  2. The Host Protein Calprotectin Modulates the Helicobacter pylori cag Type IV Secretion System via Zinc Sequestration

    PubMed Central

    Gaddy, Jennifer A.; Radin, Jana N.; Loh, John T.; Piazuelo, M. Blanca; Kehl-Fie, Thomas E.; Delgado, Alberto G.; Ilca, Florin T.; Peek, Richard M.; Cover, Timothy L.; Chazin, Walter J.; Skaar, Eric P.; Scott Algood, Holly M.

    2014-01-01

    Transition metals are necessary for all forms of life including microorganisms, evidenced by the fact that 30% of all proteins are predicted to interact with a metal cofactor. Through a process termed nutritional immunity, the host actively sequesters essential nutrient metals away from invading pathogenic bacteria. Neutrophils participate in this process by producing several metal chelating proteins, including lactoferrin and calprotectin (CP). As neutrophils are an important component of the inflammatory response directed against the bacterium Helicobacter pylori, a major risk factor for gastric cancer, it was hypothesized that CP plays a role in the host response to H. pylori. Utilizing a murine model of H. pylori infection and gastric epithelial cell co-cultures, the role CP plays in modifying H. pylori -host interactions and the function of the cag Type IV Secretion System (cag T4SS) was investigated. This study indicates elevated gastric levels of CP are associated with the infiltration of neutrophils to the H. pylori-infected tissue. When infected with an H. pylori strain harboring a functional cag T4SS, calprotectin-deficient mice exhibited decreased bacterial burdens and a trend toward increased cag T4SS -dependent inflammation compared to wild-type mice. In vitro data demonstrate that culturing H. pylori with sub-inhibitory doses of CP reduces the activity of the cag T4SS and the biogenesis of cag T4SS-associated pili in a zinc-dependent fashion. Taken together, these data indicate that zinc homeostasis plays a role in regulating the proinflammatory activity of the cag T4SS. PMID:25330071

  3. [Reactivity of antibodies to collagen types I to IV and antibodies to chondroitin sulfate in the spleen].

    PubMed

    Galbavý, S; Ruzicková, M; Surmíková, E; Danihel, L; Porubský, J; Papincák, J; Holesa, S; Trnka, J

    1996-02-01

    Antibodies to collagen type I and III reacted negatively, antibodies to collagen type IV positively with reticulin, trabeculae and circumferent reticulum of lymphatic sheaths, poorly positively with capsula, strongly positively with subcapsular zone. Antibodies to collagen type II reacted positively with capsula, poorly with subcapsular zone, strongly with sinus wall and poorly with trabeculae. They did not react with circumferent reticulum of periarterial lymphoid sheaths. Antibodies to collagen type II and IV reacted positively with central arteries. Antibodies to chondroitinsulphate C reacted poorly and antibodies to chondroitinsulphate B strongly positively with sinus walls and oval cells spread in the white and red pulpa. Antibodies to chondroitin sulphate A reacted similarly as antibodies to chondroitinsulphate B. PMID:9560890

  4. Assessing Adhesion Forces of Type I and Type IV Pili of Xylella fastidiosa Bacteria by Use of a Microfluidic Flow Chamber▿ †

    PubMed Central

    De La Fuente, Leonardo; Montanes, Emilie; Meng, Yizhi; Li, Yaxin; Burr, Thomas J.; Hoch, H. C.; Wu, Mingming

    2007-01-01

    Xylella fastidiosa, a bacterium responsible for Pierce's disease in grapevines, possesses both type I and type IV pili at the same cell pole. Type IV pili facilitate twitching motility, and type I pili are involved in biofilm development. The adhesiveness of the bacteria and the roles of the two pili types in attachment to a glass substratum were evaluated using a microfluidic flow chamber in conjunction with pilus-defective mutants. The average adhesion force necessary to detach wild-type X. fastidiosa cells was 147 ± 11 pN. Mutant cells possessing only type I pili required a force of 204 ± 22 pN for removal, whereas cells possessing only type IV pili required 119 ± 8 pN to dislodge these cells. The experimental results demonstrate that microfluidic flow chambers are useful and convenient tools for assessing the drag forces necessary for detaching bacterial cells and that with specific pilus mutants, the role of the pilus type can be further assessed. PMID:17293518

  5. Expression of the MHC Class II Transactivator (CIITA) type IV promoter in B lymphocytes and regulation by IFN-γ

    PubMed Central

    Piskurich, Janet F.; Gilbert, Carolyn A.; Ashley, Brittany D.; Zhao, Mojun; Chen, Han; Wu, Jian; Wright, Kenneth L.

    2006-01-01

    The MHC class II transactivator (CIITA), the master regulator of MHC class II (MHC II) expression, is a co-activator that controls MHC II transcription. Human B lymphocytes express MHC II constitutively due to persistent activity of CIITA promoter III (pIII), one of the four potential promoters (pI-pIV) of this gene. Although increases in MHC II expression in B cells in response to cytokines have been observed and induction of MHC II and CIITA by IFN-γ has been studied in a number of different cell types, the specific effects of IFN-γ on CIITA expression in B cells have not been studied. To investigate the regulation of CIITA expression by IFN-γ in B cells, RT-PCR, in vivo and in vitro protein/DNA binding studies, and functional promoter analyses were performed. Both MHC II and CIITA type IV-specific RNAs increased in human B lymphocytes in response to IFN-γ treatment. CIITA promoter analysis confirmed that pIV is IFN-γ inducible in B cells and that the GAS and IRF-E sites are necessary for full induction. DNA binding of IRF-1 and IRF-2, members of the IFN regulatory factor family, was up-regulated in B cells in response to IFN-γ and increased the activity of CIITA pIV. In vivo genomic footprint analysis demonstrated proteins binding at the GAS, IRF-E and E box sites of CIITA pIV. Although CIITA pIII is considered to be the hematopoietic-specific promoter of CIITA, these findings demonstrate that pIV is active in B lymphocytes and potentially contributes to the expression of CIITA and MHC II in these cells. PMID:15950283

  6. A Type IV Translocated Legionella Cysteine Phytase Counteracts Intracellular Growth Restriction by Phytate

    PubMed Central

    Weber, Stephen; Stirnimann, Christian U.; Wieser, Mara; Frey, Daniel; Meier, Roger; Engelhardt, Sabrina; Li, Xiaodan; Capitani, Guido; Kammerer, Richard A.; Hilbi, Hubert

    2014-01-01

    The causative agent of Legionnaires' pneumonia, Legionella pneumophila, colonizes diverse environmental niches, including biofilms, plant material, and protozoa. In these habitats, myo-inositol hexakisphosphate (phytate) is prevalent and used as a phosphate storage compound or as a siderophore. L. pneumophila replicates in protozoa and mammalian phagocytes within a unique “Legionella-containing vacuole.” The bacteria govern host cell interactions through the Icm/Dot type IV secretion system (T4SS) and ∼300 different “effector” proteins. Here we characterize a hitherto unrecognized Icm/Dot substrate, LppA, as a phytate phosphatase (phytase). Phytase activity of recombinant LppA required catalytically essential cysteine (Cys231) and arginine (Arg237) residues. The structure of LppA at 1.4 Å resolution revealed a mainly α-helical globular protein stabilized by four antiparallel β-sheets that binds two phosphate moieties. The phosphates localize to a P-loop active site characteristic of dual specificity phosphatases or to a non-catalytic site, respectively. Phytate reversibly abolished growth of L. pneumophila in broth, and growth inhibition was relieved by overproduction of LppA or by metal ion titration. L. pneumophila lacking lppA replicated less efficiently in phytate-loaded Acanthamoeba castellanii or Dictyostelium discoideum, and the intracellular growth defect was complemented by the phytase gene. These findings identify the chelator phytate as an intracellular bacteriostatic component of cell-autonomous host immunity and reveal a T4SS-translocated L. pneumophila phytase that counteracts intracellular bacterial growth restriction by phytate. Thus, bacterial phytases might represent therapeutic targets to combat intracellular pathogens. PMID:25339170

  7. Campylobacter fetus Subspecies Contain Conserved Type IV Secretion Systems on Multiple Genomic Islands and Plasmids

    PubMed Central

    van der Graaf–van Bloois, Linda; Miller, William G.; Yee, Emma; Gorkiewicz, Gregor; Forbes, Ken J.; Zomer, Aldert L.; Wagenaar, Jaap A.; Duim, Birgitta

    2016-01-01

    The features contributing to differences in pathogenicity of the Campylobacter fetus subspecies are unknown. Putative factors involved in pathogenesis are located in genomic islands that encode a type IV secretion system (T4SS) and fic domain (filamentation induced by cyclic AMP) proteins, which may disrupt host cell processes. In the genomes of 27 C. fetus strains, three phylogenetically-different T4SS-encoding regions (T4SSs) were identified: one was located in both the chromosome and in extra-chromosomal plasmids; one was located exclusively in the chromosome; and one exclusively in extra-chromosomal plasmids. We observed that C. fetus strains can contain multiple T4SSs and that homologous T4SSs can be present both in chromosomal genomic islands (GI) and on plasmids in the C. fetus strains. The GIs of the chromosomally located T4SS differed mainly by the presence of fic genes, insertion sequence elements and phage-related or hypothetical proteins. Comparative analysis showed that T4SS sequences, inserted in the same locations, were conserved in the studied C. fetus genomes. Using phylogenetic analysis of the T4SSs, it was shown that C. fetus may have acquired the T4SS regions from other Campylobacter species by horizontal gene transfer. The identified T4SSs and fic genes were found in Cff and Cfv strains, although the presence of T4SSs and fic genes were significantly associated with Cfv strains. The T4SSs and fic genes could not be associated with S-layer serotypes or geographical origin of the strains. PMID:27049518

  8. Functional analysis of an unusual type IV pilus in the Gram‐positive Streptococcus sanguinis

    PubMed Central

    Gurung, Ishwori; Spielman, Ingrid; Davies, Mark R.; Lala, Rajan; Gaustad, Peter; Biais, Nicolas

    2015-01-01

    Summary Type IV pili (Tfp), which have been studied extensively in a few Gram‐negative species, are the paradigm of a group of widespread and functionally versatile nano‐machines. Here, we performed the most detailed molecular characterisation of Tfp in a Gram‐positive bacterium. We demonstrate that the naturally competent S treptococcus sanguinis produces retractable Tfp, which like their Gram‐negative counterparts can generate hundreds of piconewton of tensile force and promote intense surface‐associated motility. Tfp power ‘train‐like’ directional motion parallel to the long axis of chains of cells, leading to spreading zones around bacteria grown on plates. However, S . sanguinis  Tfp are not involved in DNA uptake, which is mediated by a related but distinct nano‐machine, and are unusual because they are composed of two pilins in comparable amounts, rather than one as normally seen. Whole genome sequencing identified a locus encoding all the genes involved in Tfp biology in S . sanguinis. A systematic mutational analysis revealed that Tfp biogenesis in S . sanguinis relies on a more basic machinery (only 10 components) than in Gram‐negative species and that a small subset of four proteins dispensable for pilus biogenesis are essential for motility. Intriguingly, one of the piliated mutants that does not exhibit spreading retains microscopic motility but moves sideways, which suggests that the corresponding protein controls motion directionality. Besides establishing S . sanguinis as a useful new model for studying Tfp biology, these findings have important implications for our understanding of these widespread filamentous nano‐machines. PMID:26435398

  9. Functional analysis of an unusual type IV pilus in the Gram-positive Streptococcus sanguinis.

    PubMed

    Gurung, Ishwori; Spielman, Ingrid; Davies, Mark R; Lala, Rajan; Gaustad, Peter; Biais, Nicolas; Pelicic, Vladimir

    2016-01-01

    Type IV pili (Tfp), which have been studied extensively in a few Gram-negative species, are the paradigm of a group of widespread and functionally versatile nano-machines. Here, we performed the most detailed molecular characterisation of Tfp in a Gram-positive bacterium. We demonstrate that the naturally competent Streptococcus sanguinis produces retractable Tfp, which like their Gram-negative counterparts can generate hundreds of piconewton of tensile force and promote intense surface-associated motility. Tfp power 'train-like' directional motion parallel to the long axis of chains of cells, leading to spreading zones around bacteria grown on plates. However, S. sanguinis Tfp are not involved in DNA uptake, which is mediated by a related but distinct nano-machine, and are unusual because they are composed of two pilins in comparable amounts, rather than one as normally seen. Whole genome sequencing identified a locus encoding all the genes involved in Tfp biology in S. sanguinis. A systematic mutational analysis revealed that Tfp biogenesis in S. sanguinis relies on a more basic machinery (only 10 components) than in Gram-negative species and that a small subset of four proteins dispensable for pilus biogenesis are essential for motility. Intriguingly, one of the piliated mutants that does not exhibit spreading retains microscopic motility but moves sideways, which suggests that the corresponding protein controls motion directionality. Besides establishing S. sanguinis as a useful new model for studying Tfp biology, these findings have important implications for our understanding of these widespread filamentous nano-machines. PMID:26435398

  10. The Rickettsia type IV secretion system: unrealized complexity mired by gene family expansion.

    PubMed

    Gillespie, Joseph J; Phan, Isabelle Q H; Driscoll, Timothy P; Guillotte, Mark L; Lehman, Stephanie S; Rennoll-Bankert, Kristen E; Subramanian, Sandhya; Beier-Sexton, Magda; Myler, Peter J; Rahman, M Sayeedur; Azad, Abdu F

    2016-08-01

    Many prokaryotes utilize type IV secretion systems (T4SSs) to translocate substrates (e.g. nucleoprotein, DNA, protein) across the cell envelope, and/or to elaborate surface structures (i.e. pili or adhesins). Among eight distinct T4SS classes, P-T4SSs are typified by the Agrobacterium tumefaciens vir T4SS, which is comprised of 12 scaffold components (VirB1-VirB11, VirD4). While most P-T4SSs include all 12 Vir proteins, some differ from the vir archetype by either containing additional scaffold components not analogous to Vir proteins or lacking one or more of the Vir proteins. In a special case, the Rickettsiales vir homolog (rvh) P-T4SS comprises unprecedented gene family expansion. rvh contains three families of gene duplications (rvhB9, rvhB8, rvhB4): RvhB9,8,4-I are conserved relative to equivalents in other P-T4SSs, while RvhB9,8,4-II have evolved atypical features that deviate substantially from other homologs. Furthermore, rvh contains five VirB6-like genes (rvhB6a-e), which are tandemly arrayed and contain large N- and C-terminal extensions. Our work herein focuses on the complexity underpinned by rvh gene family expansion. Furthermore, we describe an RvhB10 insertion, which occurs in a region that forms the T4SS pore. The significance of these curious properties to rvh structure and function is evaluated, shedding light on a highly complex T4SS. PMID:27307105

  11. Prediction of bacterial type IV secreted effectors by C-terminal features

    PubMed Central

    2014-01-01

    Background Many bacteria can deliver pathogenic proteins (effectors) through type IV secretion systems (T4SSs) to eukaryotic cytoplasm, causing host diseases. The inherent property, such as sequence diversity and global scattering throughout the whole genome, makes it a big challenge to effectively identify the full set of T4SS effectors. Therefore, an effective inter-species T4SS effector prediction tool is urgently needed to help discover new effectors in a variety of bacterial species, especially those with few known effectors, e.g., Helicobacter pylori. Results In this research, we first manually annotated a full list of validated T4SS effectors from different bacteria and then carefully compared their C-terminal sequential and position-specific amino acid compositions, possible motifs and structural features. Based on the observed features, we set up several models to automatically recognize T4SS effectors. Three of the models performed strikingly better than the others and T4SEpre_Joint had the best performance, which could distinguish the T4SS effectors from non-effectors with a 5-fold cross-validation sensitivity of 89% at a specificity of 97%, based on the training datasets. An inter-species cross prediction showed that T4SEpre_Joint could recall most known effectors from a variety of species. The inter-species prediction tool package, T4SEpre, was further used to predict new T4SS effectors from H. pylori, an important human pathogen associated with gastritis, ulcer and cancer. In total, 24 new highly possible H. pylori T4S effector genes were computationally identified. Conclusions We conclude that T4SEpre, as an effective inter-species T4SS effector prediction software package, will help find new pathogenic T4SS effectors efficiently in a variety of pathogenic bacteria. PMID:24447430

  12. Phylogenomics Reveals a Diverse Rickettsiales Type IV Secretion System▿ † ‡

    PubMed Central

    Gillespie, Joseph J.; Brayton, Kelly A.; Williams, Kelly P.; Quevedo Diaz, Marco A.; Brown, Wendy C.; Azad, Abdu F.; Sobral, Bruno W.

    2010-01-01

    With an obligate intracellular lifestyle, Alphaproteobacteria of the order Rickettsiales have inextricably coevolved with their various eukaryotic hosts, resulting in small, reductive genomes and strict dependency on host resources. Unsurprisingly, large portions of Rickettsiales genomes encode proteins involved in transport and secretion. One particular transporter that has garnered recent attention from researchers is the type IV secretion system (T4SS). Homologous to the well-studied archetypal vir T4SS of Agrobacterium tumefaciens, the Rickettsiales vir homolog (rvh) T4SS is characterized primarily by duplication of several of its genes and scattered genomic distribution of all components in several conserved islets. Phylogeny estimation suggests a single event of ancestral acquirement of the rvh T4SS, likely from a nonalphaproteobacterial origin. Bioinformatics analysis of over 30 Rickettsiales genome sequences illustrates a conserved core rvh scaffold (lacking only a virB5 homolog), with lineage-specific diversification of several components (rvhB1, rvhB2, and rvhB9b), likely a result of modifications to cell envelope structure. This coevolution of the rvh T4SS and cell envelope morphology is probably driven by adaptations to various host cells, identifying the transporter as an important target for vaccine development. Despite the genetic intractability of Rickettsiales, recent advancements have been made in the characterization of several components of the rvh T4SS, as well as its putative regulators and substrates. While current data favor a role in effector translocation, functions in DNA uptake and release and/or conjugation cannot at present be ruled out, especially considering that a mechanism for plasmid transfer in Rickettsia spp. has yet to be proposed. PMID:20176788

  13. An Agrobacterium VirB10 Mutation Conferring a Type IV Secretion System Gating Defect▿

    PubMed Central

    Banta, Lois M.; Kerr, Jennifer E.; Cascales, Eric; Giuliano, Meghan E.; Bailey, Megan E.; McKay, Cedar; Chandran, Vidya; Waksman, Gabriel; Christie, Peter J.

    2011-01-01

    Agrobacterium VirB7, VirB9, and VirB10 form a “core complex” during biogenesis of the VirB/VirD4 type IV secretion system (T4SS). VirB10 spans the cell envelope and, in response to sensing of ATP energy consumption by the VirB/D4 ATPases, undergoes a conformational change required for DNA transfer across the outer membrane (OM). Here, we tested a model in which VirB10 regulates substrate passage by screening for mutations that allow for unregulated release of the VirE2 secretion substrate to the cell surface independently of target cell contact. One mutation, G272R, conferred VirE2 release and also rendered VirB10 conformationally insensitive to cellular ATP depletion. Strikingly, G272R did not affect substrate transfer to target cells (Tra+) but did block pilus production (Pil−). The G272R mutant strain displayed enhanced sensitivity to vancomycin and SDS but did not nonspecifically release periplasmic proteins or VirE2 truncated of its secretion signal. G272 is highly conserved among VirB10 homologs, including pKM101 TraF, and in the TraF X-ray structure the corresponding Gly residue is positioned near an α-helical domain termed the antenna projection (AP), which is implicated in formation of the OM pore. A partial AP deletion mutation (ΔAP) also confers a Tra+ Pil− phenotype; however, this mutation did not allow VirE2 surface exposure but instead allowed the release of pilin monomers or short oligomers to the milieu. We propose that (i) G272R disrupts a gating mechanism in the core chamber that regulates substrate passage across the OM and (ii) the G272R and ΔAP mutations block pilus production at distinct steps of the pilus biogenesis pathway. PMID:21421757

  14. Molecular and Structural Analysis of the Helicobacter pylori cag Type IV Secretion System Core Complex

    PubMed Central

    Frick-Cheng, Arwen E.; Pyburn, Tasia M.; Voss, Bradley J.; McDonald, W. Hayes

    2016-01-01

    ABSTRACT Bacterial type IV secretion systems (T4SSs) can function to export or import DNA, and can deliver effector proteins into a wide range of target cells. Relatively little is known about the structural organization of T4SSs that secrete effector proteins. In this report, we describe the isolation and analysis of a membrane-spanning core complex from the Helicobacter pylori cag T4SS, which has an important role in the pathogenesis of gastric cancer. We show that this complex contains five H. pylori proteins, CagM, CagT, Cag3, CagX, and CagY, each of which is required for cag T4SS activity. CagX and CagY are orthologous to the VirB9 and VirB10 components of T4SSs in other bacterial species, and the other three Cag proteins are unique to H. pylori. Negative stain single-particle electron microscopy revealed complexes 41 nm in diameter, characterized by a 19-nm-diameter central ring linked to an outer ring by spoke-like linkers. Incomplete complexes formed by Δcag3 or ΔcagT mutants retain the 19-nm-diameter ring but lack an organized outer ring. Immunogold labeling studies confirm that Cag3 is a peripheral component of the complex. The cag T4SS core complex has an overall diameter and structural organization that differ considerably from the corresponding features of conjugative T4SSs. These results highlight specialized features of the H. pylori cag T4SS that are optimized for function in the human gastric mucosal environment. PMID:26758182

  15. Type IV pili interactions promote intercellular association and moderate swarming of Pseudomonas aeruginosa.

    PubMed

    Anyan, Morgen E; Amiri, Aboutaleb; Harvey, Cameron W; Tierra, Giordano; Morales-Soto, Nydia; Driscoll, Callan M; Alber, Mark S; Shrout, Joshua D

    2014-12-16

    Pseudomonas aeruginosa is a ubiquitous bacterium that survives in many environments, including as an acute and chronic pathogen in humans. Substantial evidence shows that P. aeruginosa behavior is affected by its motility, and appendages known as flagella and type IV pili (TFP) are known to confer such motility. The role these appendages play when not facilitating motility or attachment, however, is unclear. Here we discern a passive intercellular role of TFP during flagellar-mediated swarming of P. aeruginosa that does not require TFP extension or retraction. We studied swarming at the cellular level using a combination of laboratory experiments and computational simulations to explain the resultant patterns of cells imaged from in vitro swarms. Namely, we used a computational model to simulate swarming and to probe for individual cell behavior that cannot currently be otherwise measured. Our simulations showed that TFP of swarming P. aeruginosa should be distributed all over the cell and that TFP-TFP interactions between cells should be a dominant mechanism that promotes cell-cell interaction, limits lone cell movement, and slows swarm expansion. This predicted physical mechanism involving TFP was confirmed in vitro using pairwise mixtures of strains with and without TFP where cells without TFP separate from cells with TFP. While TFP slow swarm expansion, we show in vitro that TFP help alter collective motion to avoid toxic compounds such as the antibiotic carbenicillin. Thus, TFP physically affect P. aeruginosa swarming by actively promoting cell-cell association and directional collective motion within motile groups to aid their survival. PMID:25468980

  16. A type IV translocated Legionella cysteine phytase counteracts intracellular growth restriction by phytate.

    PubMed

    Weber, Stephen; Stirnimann, Christian U; Wieser, Mara; Frey, Daniel; Meier, Roger; Engelhardt, Sabrina; Li, Xiaodan; Capitani, Guido; Kammerer, Richard A; Hilbi, Hubert

    2014-12-01

    The causative agent of Legionnaires' pneumonia, Legionella pneumophila, colonizes diverse environmental niches, including biofilms, plant material, and protozoa. In these habitats, myo-inositol hexakisphosphate (phytate) is prevalent and used as a phosphate storage compound or as a siderophore. L. pneumophila replicates in protozoa and mammalian phagocytes within a unique "Legionella-containing vacuole." The bacteria govern host cell interactions through the Icm/Dot type IV secretion system (T4SS) and ∼300 different "effector" proteins. Here we characterize a hitherto unrecognized Icm/Dot substrate, LppA, as a phytate phosphatase (phytase). Phytase activity of recombinant LppA required catalytically essential cysteine (Cys(231)) and arginine (Arg(237)) residues. The structure of LppA at 1.4 Å resolution revealed a mainly α-helical globular protein stabilized by four antiparallel β-sheets that binds two phosphate moieties. The phosphates localize to a P-loop active site characteristic of dual specificity phosphatases or to a non-catalytic site, respectively. Phytate reversibly abolished growth of L. pneumophila in broth, and growth inhibition was relieved by overproduction of LppA or by metal ion titration. L. pneumophila lacking lppA replicated less efficiently in phytate-loaded Acanthamoeba castellanii or Dictyostelium discoideum, and the intracellular growth defect was complemented by the phytase gene. These findings identify the chelator phytate as an intracellular bacteriostatic component of cell-autonomous host immunity and reveal a T4SS-translocated L. pneumophila phytase that counteracts intracellular bacterial growth restriction by phytate. Thus, bacterial phytases might represent therapeutic targets to combat intracellular pathogens. PMID:25339170

  17. The Coxiella burnetii Cryptic Plasmid Is Enriched in Genes Encoding Type IV Secretion System Substrates▿ †

    PubMed Central

    Voth, Daniel E.; Beare, Paul A.; Howe, Dale; Sharma, Uma M.; Samoilis, Georgios; Cockrell, Diane C.; Omsland, Anders; Heinzen, Robert A.

    2011-01-01

    The intracellular bacterial pathogen Coxiella burnetii directs biogenesis of a phagolysosome-like parasitophorous vacuole (PV), in which it replicates. The organism encodes a Dot/Icm type IV secretion system (T4SS) predicted to deliver to the host cytosol effector proteins that mediate PV formation and other cellular events. All C. burnetii isolates carry a large, autonomously replicating plasmid or have chromosomally integrated plasmid-like sequences (IPS), suggesting that plasmid and IPS genes are critical for infection. Bioinformatic analyses revealed two candidate Dot/Icm substrates with eukaryotic-like motifs uniquely encoded by the QpH1 plasmid from the Nine Mile reference isolate. CpeC, containing an F-box domain, and CpeD, possessing kinesin-related and coiled-coil regions, were secreted by the closely related Legionella pneumophila Dot/Icm T4SS. An additional QpH1-specific gene, cpeE, situated in a predicted operon with cpeD, also encoded a secreted effector. Further screening revealed that three hypothetical proteins (CpeA, CpeB, and CpeF) encoded by all C. burnetii plasmids and IPS are Dot/Icm substrates. By use of new genetic tools, secretion of plasmid effectors by C. burnetii during host cell infection was confirmed using β-lactamase and adenylate cyclase translocation assays, and a C-terminal secretion signal was identified. When ectopically expressed in HeLa cells, plasmid effectors trafficked to different subcellular sites, including autophagosomes (CpeB), ubiquitin-rich compartments (CpeC), and the endoplasmic reticulum (CpeD). Collectively, these results suggest that C. burnetii plasmid-encoded T4SS substrates play important roles in subversion of host cell functions, providing a plausible explanation for the absolute maintenance of plasmid genes by this pathogen. PMID:21216993

  18. Type IV pili interactions promote intercellular association and moderate swarming of Pseudomonas aeruginosa

    PubMed Central

    Anyan, Morgen E.; Amiri, Aboutaleb; Harvey, Cameron W.; Tierra, Giordano; Morales-Soto, Nydia; Driscoll, Callan M.; Alber, Mark S.; Shrout, Joshua D.

    2014-01-01

    Pseudomonas aeruginosa is a ubiquitous bacterium that survives in many environments, including as an acute and chronic pathogen in humans. Substantial evidence shows that P. aeruginosa behavior is affected by its motility, and appendages known as flagella and type IV pili (TFP) are known to confer such motility. The role these appendages play when not facilitating motility or attachment, however, is unclear. Here we discern a passive intercellular role of TFP during flagellar-mediated swarming of P. aeruginosa that does not require TFP extension or retraction. We studied swarming at the cellular level using a combination of laboratory experiments and computational simulations to explain the resultant patterns of cells imaged from in vitro swarms. Namely, we used a computational model to simulate swarming and to probe for individual cell behavior that cannot currently be otherwise measured. Our simulations showed that TFP of swarming P. aeruginosa should be distributed all over the cell and that TFP−TFP interactions between cells should be a dominant mechanism that promotes cell−cell interaction, limits lone cell movement, and slows swarm expansion. This predicted physical mechanism involving TFP was confirmed in vitro using pairwise mixtures of strains with and without TFP where cells without TFP separate from cells with TFP. While TFP slow swarm expansion, we show in vitro that TFP help alter collective motion to avoid toxic compounds such as the antibiotic carbenicillin. Thus, TFP physically affect P. aeruginosa swarming by actively promoting cell−cell association and directional collective motion within motile groups to aid their survival. PMID:25468980

  19. Apolipoprotein(a) Kringle-IV Type 2 Copy Number Variation Is Associated with Venous Thromboembolism

    PubMed Central

    Sticchi, Elena; Magi, Alberto; Kamstrup, Pia R.; Marcucci, Rossella; Prisco, Domenico; Martinelli, Ida; Mannucci, Pier Mannuccio; Abbate, Rosanna; Giusti, Betti

    2016-01-01

    In addition to the established association between high lipoprotein(a) [Lp(a)] concentrations and coronary artery disease, an association between Lp(a) and venous thromboembolism (VTE) has also been described. Lp(a) is controlled by genetic variants in LPA gene, coding for apolipoprotein(a), including the kringle-IV type 2 (KIV-2) size polymorphism. Aim of the study was to investigate the role of LPA gene KIV-2 size polymorphism and single nucleotide polymorphisms (SNPs) (rs1853021, rs1800769, rs3798220, rs10455872) in modulating VTE susceptibility. Five hundred and sixteen patients with VTE without hereditary and acquired thrombophilia and 1117 healthy control subjects, comparable for age and sex, were investigated. LPA KIV-2 polymorphism, rs3798220 and rs10455872 SNPs were genotyped by TaqMan technology. Concerning rs1853021 and rs1800769 SNPs, PCR-RFLP assay was used. LPA KIV-2 repeat number was significantly lower in patients than in controls [median (interquartile range) 11(6–17) vs 15(9–25), p<0.0001]. A significantly higher prevalence of KIV-2 repeat number ≤7 was observed in patients than in controls (33.5% vs 15.5%, p<0.0001). KIV-2 repeat number was independently associated with VTE (p = 4.36 x10-9), as evidenced by the general linear model analysis adjusted for transient risk factors. No significant difference in allele frequency for all SNPs investigated was observed. Haplotype analysis showed that LPA haplotypes rather than individual SNPs influenced disease susceptibility. Receiver operating characteristic curves analysis showed that a combined risk prediction model, including KIV-2 size polymorphism and clinical variables, had a higher performance in identifying subjects at VTE risk than a clinical-only model, also separately in men and women. PMID:26900838

  20. Apolipoprotein(a) Kringle-IV Type 2 Copy Number Variation Is Associated with Venous Thromboembolism.

    PubMed

    Sticchi, Elena; Magi, Alberto; Kamstrup, Pia R; Marcucci, Rossella; Prisco, Domenico; Martinelli, Ida; Mannucci, Pier Mannuccio; Abbate, Rosanna; Giusti, Betti

    2016-01-01

    In addition to the established association between high lipoprotein(a) [Lp(a)] concentrations and coronary artery disease, an association between Lp(a) and venous thromboembolism (VTE) has also been described. Lp(a) is controlled by genetic variants in LPA gene, coding for apolipoprotein(a), including the kringle-IV type 2 (KIV-2) size polymorphism. Aim of the study was to investigate the role of LPA gene KIV-2 size polymorphism and single nucleotide polymorphisms (SNPs) (rs1853021, rs1800769, rs3798220, rs10455872) in modulating VTE susceptibility. Five hundred and sixteen patients with VTE without hereditary and acquired thrombophilia and 1117 healthy control subjects, comparable for age and sex, were investigated. LPA KIV-2 polymorphism, rs3798220 and rs10455872 SNPs were genotyped by TaqMan technology. Concerning rs1853021 and rs1800769 SNPs, PCR-RFLP assay was used. LPA KIV-2 repeat number was significantly lower in patients than in controls [median (interquartile range) 11(6-17) vs 15(9-25), p<0.0001]. A significantly higher prevalence of KIV-2 repeat number ≤7 was observed in patients than in controls (33.5% vs 15.5%, p<0.0001). KIV-2 repeat number was independently associated with VTE (p = 4.36 x10-9), as evidenced by the general linear model analysis adjusted for transient risk factors. No significant difference in allele frequency for all SNPs investigated was observed. Haplotype analysis showed that LPA haplotypes rather than individual SNPs influenced disease susceptibility. Receiver operating characteristic curves analysis showed that a combined risk prediction model, including KIV-2 size polymorphism and clinical variables, had a higher performance in identifying subjects at VTE risk than a clinical-only model, also separately in men and women. PMID:26900838

  1. Peptidomimetic Small Molecules Disrupt Type IV Secretion System Activity in Diverse Bacterial Pathogens

    PubMed Central

    Shaffer, Carrie L.; Good, James A. D.; Kumar, Santosh; Krishnan, K. Syam; Gaddy, Jennifer A.; Loh, John T.; Chappell, Joseph; Almqvist, Fredrik

    2016-01-01

    ABSTRACT Bacteria utilize complex type IV secretion systems (T4SSs) to translocate diverse effector proteins or DNA into target cells. Despite the importance of T4SSs in bacterial pathogenesis, the mechanism by which these translocation machineries deliver cargo across the bacterial envelope remains poorly understood, and very few studies have investigated the use of synthetic molecules to disrupt T4SS-mediated transport. Here, we describe two synthetic small molecules (C10 and KSK85) that disrupt T4SS-dependent processes in multiple bacterial pathogens. Helicobacter pylori exploits a pilus appendage associated with the cag T4SS to inject an oncogenic effector protein (CagA) and peptidoglycan into gastric epithelial cells. In H. pylori, KSK85 impedes biogenesis of the pilus appendage associated with the cag T4SS, while C10 disrupts cag T4SS activity without perturbing pilus assembly. In addition to the effects in H. pylori, we demonstrate that these compounds disrupt interbacterial DNA transfer by conjugative T4SSs in Escherichia coli and impede vir T4SS-mediated DNA delivery by Agrobacterium tumefaciens in a plant model of infection. Of note, C10 effectively disarmed dissemination of a derepressed IncF plasmid into a recipient bacterial population, thus demonstrating the potential of these compounds in mitigating the spread of antibiotic resistance determinants driven by conjugation. To our knowledge, this study is the first report of synthetic small molecules that impair delivery of both effector protein and DNA cargos by diverse T4SSs. PMID:27118587

  2. EFFICACY OF PULSED DYE LASER IN COSMETICALLY DISTRESSING FACIAL DERMATOSES IN SKIN TYPES IV AND V

    PubMed Central

    Khandpur, Sujay; Sharma, Vinod K

    2008-01-01

    Background: Pulsed dye laser (PDL) has revolutionized treatment of vascular dermatoses. It has been successfully employed to treat several non-vascular conditions in fair skinned individuals without producing significant pigmentary and textural complications. Aim: A preliminary study was undertaken to assess its efficacy in cosmetically distressing facial, vascular and non-vascular dermatoses in Indian patients with skin types IV and V. Materials and Methods: Nine patients of ages 7 to 55 years, with facial verruca plana (VP- 4 cases), angiofibromas (AF- 4 cases) and multiple pyogenic granulomas (PG- one case) were recruited. They had no systemic complaints. Laser parameters used were (spot size/fluence/wavelength/pulse duration):VP- 5mm/5.5-7.5J/585nm/0.45ms; AF-5mm/6-8.5J/585nm/0.45ms;PG- 5mm/7J/585 and 595nm alternately/1.5ms. Response was assessed clinically and photographically. Results and Conclusions: All VP lesions completely resolved after 2-4 sessions (mean 3.25 sessions), AF showed 50% regression in all cases after 2-3 sessions (mean 2.5 sessions) and ≥75% subsidence after 3-7 sessions (mean 5.5 sessions) and in PG, after 3 sessions, there was complete subsidence of small satellite lesions with moderate shrinkage of larger papules and complete resolution after 5 sessions. Complications included transient hyperpigmentation/hypopigmentation only. There was no recurrence during next 6 months. PDL offers significant cosmetic improvement in facial dermatoses in Indian patients. PMID:19882031

  3. Functional divergence of FimX in PilZ binding and type IV pilus regulation.

    PubMed

    Qi, Yaning; Xu, Linghui; Dong, Xueming; Yau, Yin Hoe; Ho, Chun Loong; Koh, Siew Lee; Shochat, Susana Geifman; Chou, Shan-Ho; Tang, Kai; Liang, Zhao-Xun

    2012-11-01

    Type IV pili (T4P) are polar surface structures that play important roles in bacterial motility, biofilm formation, and pathogenicity. The protein FimX and its orthologs are known to mediate T4P formation in the human pathogen Pseudomonas aeruginosa and some other bacterial species. It was reported recently that FimX(XAC2398) from Xanthomonas axonopodis pv. citri interacts with PilZ(XAC1133) directly through the nonenzymatic EAL domain of FimX(XAC2398). Here we present experimental data to reveal that the strong interaction between FimX(XAC2398) and PilZ(XAC1133) is not conserved in P. aeruginosa and likely other Pseudomonas species. In vitro and in vivo binding experiments showed that the interaction between FimX and PilZ in P. aeruginosa is below the measurable limit. Surface plasmon resonance assays further confirmed that the interaction between the P. aeruginosa proteins is at least more than 3 orders of magnitude weaker than that between the X. axonopodis pv. citri pair. The N-terminal lobe region of FimX(XAC2398) was identified as the binding surface for PilZ(XAC1133) by amide hydrogen-deuterium exchange and site-directed mutagenesis studies. Lack of several key residues in the N-terminal lobe region of the EAL domain of FimX is likely to account for the greatly reduced binding affinity between FimX and PilZ in P. aeruginosa. All together, the results suggest that the interaction between PilZ and FimX in Xanthomonas species is not conserved in P. aeruginosa due to the evolutionary divergence among the FimX orthologs. The precise roles of FimX and PilZ in bacterial motility and T4P biogenesis are likely to vary among bacterial species. PMID:22942245

  4. The initial stage of development of type IV radio bursts and the relation to expanding magnetic bottles

    NASA Technical Reports Server (NTRS)

    Sakurai, K.

    1973-01-01

    Using the observed data for wideband type IV solar radio bursts, the onset time differences between the microwave and metric frequencies and the peak flux intensities of the metric component are analyzed as a function of the longitudinal position of the associated flares on the solar disk. It is shown that this time difference is dependent on the position of the associated flare and that the peak flux intensity reaches maximum when a flare occurs in the region from 10 to 40 deg west of the central meridian of the solar disk. These results are explained by taking into account the eastward expansion of magnetic bottles which trap mildly relativistic electrons responsible for type IV bursts. The relation between these magnetic bottles and shock waves which excite type II radio bursts is discussed.

  5. The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. II.Type II Cepheids and Anomalous Cepheids in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Soszyński, I.; Udalski, A.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Wyrzykowski, Ł.; Szewczyk, O.; Ulaczyk, K.; Poleski, R.

    2008-12-01

    In the second part of the OGLE-III Catalog of Variable Stars (OIII-CVS) we present 197 type II Cepheids and 83 anomalous Cepheids in the Large Magellanic Cloud (LMC). The sample of type II Cepheids consists of 64 BL Her stars, 96 W Vir stars and 37 RV Tau stars. Anomalous Cepheids are divided into 62 fundamental-mode and 21 first-overtone pulsators. These are the largest samples of such types of variable stars detected anywhere outside the Galaxy. We present the period-luminosity and color-magnitude diagrams of stars in the sample. If the boundary period between BL Her and W Vir stars is adopted at 4 days, both groups differ significantly in (V-I) colors. We identify a group of 16 peculiar W Vir stars with different appearance of the light curves, brighter and bluer than ordinary stars of that type. Four of these peculiar W Vir stars show additional eclipsing modulation superimposed on the pulsation light curves. Four other stars of that type show long-period secondary variations which may be ellipsoidal modulations. It suggests that peculiar W Vir subgroup may be related to binarity. In total, we identified seven type II Cepheids simultaneously exhibiting eclipsing variations which is a very large fraction compared to classical Cepheids in the LMC. We discuss diagrams showing Fourier parameters of the light curve decomposition against periods. Three sharp features interpreted as an effect of resonances between radial modes are detectable in these diagrams for type II Cepheids.

  6. Enterococcus faecalis adhesin, ace, mediates attachment to extracellular matrix proteins collagen type IV and laminin as well as collagen type I.

    PubMed

    Nallapareddy, S R; Qin, X; Weinstock, G M; Höök, M; Murray, B E

    2000-09-01

    Adhesin-mediated binding to extracellular matrix (ECM) proteins is thought to be a crucial step in the pathogenic process of many bacterial infections. We have previously reported conditional adherence of most Enterococcus faecalis isolates, after growth at 46 degrees C, to ECM proteins collagen types I and IV and laminin; identified an E. faecalis-specific gene, ace, whose encoded protein has characteristics of a bacterial adhesin; and implicated Ace in binding to collagen type I. In this study, we constructed an ace disruption mutant from E. faecalis strain OG1RF that showed marked reduction in adherence to collagen types I and IV and laminin when compared to the parental OG1RF strain after growth at 46 degrees C. Polyclonal immune serum raised against the OG1RF-derived recombinant Ace A domain reacted with a single approximately 105-kDa band of mutanolysin extracts from OG1RF grown at 46 degrees C, while no band was detected in extracts from OG1RF grown at 37 degrees C, nor from the OG1RF ace mutant grown at 37 or 46 degrees C. IgGs purified from the anti-Ace A immune serum inhibited adherence of 46 degrees C-grown E. faecalis OG1RF to immobilized collagen type IV and laminin as well as collagen type I, at a concentration as low as 1 microg/ml, and also inhibited the 46 degrees C-evoked adherence of two clinical isolates tested. We also showed in vitro interaction of collagen type IV with Ace from OG1RF mutanolysin extracts on a far-Western blot. Binding of recombinant Ace A to immobilized collagen types I and IV and laminin was demonstrated in an enzyme-linked immunosorbent assay and was shown to be concentration dependent. These results indicate that Ace A mediates the conditional binding of E. faecalis OG1RF to collagen type IV and laminin in addition to collagen type I. PMID:10948147

  7. Undiagnosed Borrmann type IV gastric cancer despite repeated endoscopic biopsies and PET-CT examination: A case report

    PubMed Central

    Zhu, Fang-Qing; Chu, Hong-Jin; Gong, Zhao-Hua; Du, Feng-Cai; Chen, Jian; Jiang, Li-Xin

    2016-01-01

    Borrmann type IV gastric cancer is a particular histological type of carcinoma, which has the characteristic of diffused infiltration that invades the entire stomach, resulting in the thickening and stiffness of the stomach wall. Borrmann type IV gastric cancer is known for the difficulty of detecting tumor cells in endoscopic biopsy specimens. This is crucial in obtaining the pathological results to make a therapeutic decision. The case reported in the present study was highly suspected to be Borrmann type IV gastric cancer according to the clinical manifestations and gastrointestinal barium meal examinations, but demonstrated negative results in multiple endoscopic biopsies and positron emission tomography-computed tomography (PET-CT) examination. The patient was discharged as no affirmative diagnosis was specified. Two weeks after discharge, the patient was administered to another hospital under emergency treatment due to frequent urination. Cystoscopy examination revealed marked thickening of the right bladder wall over a large area. Biopsy specimens were sampled. Pathological consultation suggested a gastrointestinal original of the lesion, which was most likely poorly differentiated gastric adenocarcinoma with neuroendocrine metastasis to the bladder. PMID:27446457

  8. The determination of PCBs in Rocky Flats Type IV waste sludge by gas chromatography/electron capture detection. Part 2

    SciTech Connect

    Parish, K.J.; Applegate, D.V.; Postlethwait, P.D.; Boparai, A.S.; Reedy, G.T.

    1994-12-01

    Before disposal, radioactive sludge (Type IV) from Rocky Flats Plant (RFP) must be evaluated for polychlorinated biphenyl (PCB) content. The Type IV sludge consists of organic solvents, degreasers, cutting oils, and transuranic (TRU) waste mixed with calcium silicate (MicroCel E{reg_sign} and Oil Dri{reg_sign} to form a grease or paste-like material. For laboratory testing, a nonradioactive simulated Type 17V RFP sludge was prepared at Argonne National Laboratory-East (ANL-E). This sludge has a composition similar to that expected from field samples. In an earlier effort, a simplified method was developed for extraction, cleanup of extract, and determination of PCBs in samples of simulated sludge spiked with Aroclors 1254 and 1260. The simplified method has now been used to determine the presence and quantities of other Aroclors in the simulated sludge, namely, Aroclors 10 1 6, 1221, 1232, 1242, and 1248. The accuracy and precision of the data for these Aroclors were found to be similar to the data for sludges spiked with Aroclors 1254 and 1260. Since actual sludges may vary in composition, the method was also verified by analyzing another source of Type IV simulated sludge, prepared by Argonne National Laboratory-West (ANL-W).

  9. Familial Amyloid Polyneuropathy Type IV (FINNISH) with Rapid Clinical Progression in an Iranian Woman: A Case Report.

    PubMed

    Babaei-Ghazani, Arash; Eftekharsadat, Bina

    2016-05-01

    Familial amyloid polyneuropathy (FAP) type IV (FINNISH) is a rare clinical entity with challenging neuropathy and cosmetic deficits. Amyloidosis can affect peripheral sensory, motor, or autonomic nerves. Nerve lesions are induced by deposits of amyloid fibrils and treatment approaches for neuropathy are challenging. Involvement of cranial nerves and atrophy in facial muscles is a real concern in daily life of such patients. Currently, diagnosis of neuropathy can be made by electrodiagnostic studies and diagnosis of amyloidosis can be made by genetic testing or by detection of amyloid deposition in abdominal fat pad, rectal, or nerve biopsies. It is preferable to consider FAP as one of the differential diagnosis of a case presented with multiple cranial nerves symptoms. The authors present a case of familial amyloid polyneuropathy (FAP) type IV with severe involvement of multiple cranial nerves, peripheral limb neuropathy, and orthostatic hypotension. PMID:27217609

  10. A Comparative Structure/Function Analysis of Two Type IV Pilin DNA Receptors Defines a Novel Mode of DNA Binding.

    PubMed

    Berry, Jamie-Lee; Xu, Yingqi; Ward, Philip N; Lea, Susan M; Matthews, Stephen J; Pelicic, Vladimir

    2016-06-01

    DNA transformation is a widespread process allowing bacteria to capture free DNA by using filamentous nano-machines composed of type IV pilins. These proteins can act as DNA receptors as demonstrated by the finding that Neisseria meningitidis ComP minor pilin has intrinsic DNA-binding ability. ComP binds DNA better when it contains the DNA-uptake sequence (DUS) motif abundant in this species genome, playing a role in its trademark ability to selectively take up its own DNA. Here, we report high-resolution structures for meningococcal ComP and Neisseria subflava ComPsub, which recognize different DUS motifs. We show that they are structurally identical type IV pilins that pack readily into filament models and display a unique DD region delimited by two disulfide bonds. Functional analysis of ComPsub defines a new mode of DNA binding involving the DD region, adapted for exported DNA receptors. PMID:27161979

  11. Placement of ¹²⁵I seed strands and stents for a type IV Klatskin tumor.

    PubMed

    Zhang, Wen; Yang, Zheng-Qiang; Shi, Hai-Bin; Liu, Shen; Zhou, Wei-Zhong; Zhao, Lin-Bo

    2015-01-01

    Herein, we report a new technique that consists of placing two (125)I seed strands and two stents in the right and left intrahepatic bile ducts for the treatment of hilar cholangiocarcinoma. A 75-year-old man presented with jaundice and was diagnosed with Bismuth type IV Klatskin tumor. Abdominal computed tomography (CT) showed intrahepatic and extrahepatic bile duct dilatation and a soft tissue mass in the hepatic hilum. Because curative surgical resection was not possible, we placed (125)I seed strands and stents in the right and left intrahepatic bile ducts. Three months later, abdominal CT showed less intrahepatic and extrahepatic bile duct dilatation than before the procedure. This technique was feasible and could be considered for the treatment of patients with Bismuth type IV tumors. PMID:25574114

  12. New type of blue ternary complex of arsenazo I with plutonium (IV) in the presence of hydrogen peroxide: preliminary investigations.

    PubMed

    Pérez-Bustamante, J A

    1974-12-01

    The preparation and spectrophotometric properties of a new type of complex compound of arsenazo I with Pu(IV) in the presence of H(2)O(2) are described. The new compound has a blue colour, derived from a wide absorption band with a maximum at 610 nm. and a corresponding molar absorptivity of 4 x 10(4) l. mole(-1).cm(-1). From 2 hr after its preparation this curious new compound undergoes for several days a steady decomposition accompanied by decolorization. The formation of similar peroxy Pu(IV) complexes has not so far been shown to take place with arsenazo III or with any other "arsenazo-type" reagent. PMID:18961599

  13. Familial Amyloid Polyneuropathy Type IV (FINNISH) with Rapid Clinical Progression in an Iranian Woman: A Case Report

    PubMed Central

    Babaei-Ghazani, Arash; Eftekharsadat, Bina

    2016-01-01

    Familial amyloid polyneuropathy (FAP) type IV (FINNISH) is a rare clinical entity with challenging neuropathy and cosmetic deficits. Amyloidosis can affect peripheral sensory, motor, or autonomic nerves. Nerve lesions are induced by deposits of amyloid fibrils and treatment approaches for neuropathy are challenging. Involvement of cranial nerves and atrophy in facial muscles is a real concern in daily life of such patients. Currently, diagnosis of neuropathy can be made by electrodiagnostic studies and diagnosis of amyloidosis can be made by genetic testing or by detection of amyloid deposition in abdominal fat pad, rectal, or nerve biopsies. It is preferable to consider FAP as one of the differential diagnosis of a case presented with multiple cranial nerves symptoms. The authors present a case of familial amyloid polyneuropathy (FAP) type IV with severe involvement of multiple cranial nerves, peripheral limb neuropathy, and orthostatic hypotension. PMID:27217609

  14. Structure of the type IV secretion system in different strains of Anaplasma phagocytophilum

    PubMed Central

    2012-01-01

    Background Anaplasma phagocytophilum is an intracellular organism in the Order Rickettsiales that infects diverse animal species and is causing an emerging disease in humans, dogs and horses. Different strains have very different cell tropisms and virulence. For example, in the U.S., strains have been described that infect ruminants but not dogs or rodents. An intriguing question is how the strains of A. phagocytophilum differ and what different genome loci are involved in cell tropisms and/or virulence. Type IV secretion systems (T4SS) are responsible for translocation of substrates across the cell membrane by mechanisms that require contact with the recipient cell. They are especially important in organisms such as the Rickettsiales which require T4SS to aid colonization and survival within both mammalian and tick vector cells. We determined the structure of the T4SS in 7 strains from the U.S. and Europe and revised the sequence of the repetitive virB6 locus of the human HZ strain. Results Although in all strains the T4SS conforms to the previously described split loci for vir genes, there is great diversity within these loci among strains. This is particularly evident in the virB2 and virB6 which are postulated to encode the secretion channel and proteins exposed on the bacterial surface. VirB6-4 has an unusual highly repetitive structure and can have a molecular weight greater than 500,000. For many of the virs, phylogenetic trees position A. phagocytophilum strains infecting ruminants in the U.S. and Europe distant from strains infecting humans and dogs in the U.S. Conclusions Our study reveals evidence of gene duplication and considerable diversity of T4SS components in strains infecting different animals. The diversity in virB2 is in both the total number of copies, which varied from 8 to 15 in the herein characterized strains, and in the sequence of each copy. The diversity in virB6 is in the sequence of each of the 4 copies in the single locus and the

  15. Truncation of type IV pilin induces mucoidy in Pseudomonas aeruginosa strain PAO579

    PubMed Central

    Ryan Withers, T; Heath Damron, F; Yin, Yeshi; Yu, Hongwei D

    2013-01-01

    Pseudomonas aeruginosa is a Gram negative, opportunistic pathogen that uses the overproduction of alginate, a surface polysaccharide, to form biofilms in vivo. Overproduction of alginate, also known as mucoidy, affords the bacterium protection from the host's defenses and facilitates the establishment of chronic lung infections in individuals with cystic fibrosis. Expression of the alginate biosynthetic operon is primarily controlled by the alternative sigma factor AlgU (AlgT/σ22). In a nonmucoid strain, AlgU is sequestered by the transmembrane antisigma factor MucA to the cytoplasmic membrane. AlgU can be released from MucA via regulated intramembrane proteolysis by proteases AlgW and MucP causing the conversion to mucoidy. Pseudomonas aeruginosa strain PAO579, a derivative of the nonmucoid strain PAO1, is mucoid due to an unidentified mutation (muc-23). Using whole genome sequencing, we identified 16 nonsynonymous and 15 synonymous single nucleotide polymorphisms (SNP). We then identified three tandem single point mutations in the pilA gene (PA4525), as the cause of mucoidy in PAO579. These tandem mutations generate a premature stop codon resulting in a truncated version of PilA (PilA108), with a C-terminal motif of phenylalanine-threonine-phenylalanine (FTF). Inactivation of pilA108 confirmed it was required for mucoidy. Additionally, algW and algU were also required for mucoidy of PAO579. Western blot analysis indicated that MucA was less stable in PAO579 than nonmucoid PAO1 or PAO381. The mucoid phenotype and high PalgU and PalgD promoter activities of PAO579 require pilA108, algW, algU, and rpoN encoding the alternative sigma factor σ54. We also observed that RpoN regulates expression of algW and pilA in PAO579. Together, these results suggest that truncation in type IV pilin in P. aeruginosa strain PAO579 can induce mucoidy through an AlgW/AlgU-dependent pathway. PMID:23533140

  16. Structural Insight into How Bacteria Prevent Interference between Multiple Divergent Type IV Secretion Systems

    PubMed Central

    Phan, Isabelle Q. H.; Scheib, Holger; Subramanian, Sandhya; Edwards, Thomas E.; Lehman, Stephanie S.; Piitulainen, Hanna; Sayeedur Rahman, M.; Rennoll-Bankert, Kristen E.; Staker, Bart L.; Taira, Suvi; Stacy, Robin; Myler, Peter J.; Azad, Abdu F.

    2015-01-01

    ABSTRACT Prokaryotes use type IV secretion systems (T4SSs) to translocate substrates (e.g., nucleoprotein, DNA, and protein) and/or elaborate surface structures (i.e., pili or adhesins). Bacterial genomes may encode multiple T4SSs, e.g., there are three functionally divergent T4SSs in some Bartonella species (vir, vbh, and trw). In a unique case, most rickettsial species encode a T4SS (rvh) enriched with gene duplication. Within single genomes, the evolutionary and functional implications of cross-system interchangeability of analogous T4SS protein components remains poorly understood. To lend insight into cross-system interchangeability, we analyzed the VirB8 family of T4SS channel proteins. Crystal structures of three VirB8 and two TrwG Bartonella proteins revealed highly conserved C-terminal periplasmic domain folds and dimerization interfaces, despite tremendous sequence divergence. This implies remarkable structural constraints for VirB8 components in the assembly of a functional T4SS. VirB8/TrwG heterodimers, determined via bacterial two-hybrid assays and molecular modeling, indicate that differential expression of trw and vir systems is the likely barrier to VirB8-TrwG interchangeability. We also determined the crystal structure of Rickettsia typhi RvhB8-II and modeled its coexpressed divergent paralog RvhB8-I. Remarkably, while RvhB8-I dimerizes and is structurally similar to other VirB8 proteins, the RvhB8-II dimer interface deviates substantially from other VirB8 structures, potentially preventing RvhB8-I/RvhB8-II heterodimerization. For the rvh T4SS, the evolution of divergent VirB8 paralogs implies a functional diversification that is unknown in other T4SSs. Collectively, our data identify two different constraints (spatiotemporal for Bartonella trw and vir T4SSs and structural for rvh T4SSs) that mediate the functionality of multiple divergent T4SSs within a single bacterium. PMID:26646013

  17. Cyclic Di-GMP Regulates Type IV Pilus-Dependent Motility in Myxococcus xanthus

    PubMed Central

    Skotnicka, Dorota; Petters, Tobias; Heering, Jan; Hoppert, Michael; Kaever, Volkhard

    2015-01-01

    ABSTRACT The nucleotide-based second messenger bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) is involved in regulating a plethora of processes in bacteria that are typically associated with lifestyle changes. Myxococcus xanthus undergoes major lifestyle changes in response to nutrient availability, with the formation of spreading colonies in the presence of nutrients and spore-filled fruiting bodies in the absence of nutrients. Here, we investigated the function of c-di-GMP in M. xanthus and show that this bacterium synthesizes c-di-GMP during growth. Manipulation of the c-di-GMP level by expression of either an active, heterologous diguanylate cyclase or an active, heterologous phosphodiesterase correlated with defects in type IV pilus (T4P)-dependent motility, whereas gliding motility was unaffected. An increased level of c-di-GMP correlated with reduced transcription of the pilA gene (which encodes the major pilin of T4P), reduced the assembly of T4P, and altered cell agglutination, whereas a decreased c-di-GMP level correlated with altered cell agglutination. The systematic inactivation of the 24 genes in M. xanthus encoding proteins containing GGDEF, EAL, or HD-GYP domains, which are associated with c-di-GMP synthesis, degradation, or binding, identified three genes encoding proteins important for T4P-dependent motility, whereas all mutants had normal gliding motility. Purified DmxA had diguanylate cyclase activity, whereas the hybrid histidine protein kinases TmoK and SgmT, each of which contains a GGDEF domain, did not have diguanylate cyclase activity. These results demonstrate that c-di-GMP is important for T4P-dependent motility in M. xanthus. IMPORTANCE We provide the first direct evidence that M. xanthus synthesizes c-di-GMP and demonstrate that c-di-GMP is important for T4P-dependent motility, whereas we did not obtain evidence that c-di-GMP regulates gliding motility. The data presented uncovered a novel mechanism for regulation of T4P

  18. Anomalous resistivity effect on multiple ion beam emission and hard x-ray generation in a Mather type plasma focus device

    SciTech Connect

    Behbahani, R. A.; Aghamir, F. M.

    2011-10-15

    Multi ion beam and hard x-ray emissions were detected in a high inductance (more than 100 nH) Mather type plasma focus (PF) device at different filling gas pressures and charging voltages. The signal analysis was performed through the current trace, as it is the fundamental signal from which all of the phenomena in a PF device can be extracted. Two different fitting processes were carried out according to Lee's computational (snow-plow) model. In the first process, only plasma dynamics and classical (Spitzer) resistances were considered as energy consumer parameters for plasma. This led to an unsuccessful fitting and did not answer the energy transfer mechanism into plasma. A second fitting process was considered through the addition of anomalous resistance, which provided the best fit. Anomalous resistance was the source of long decrease in current trace, and multi dips and multi peaks of high voltage probe. Multi-peak features were interpreted considering the second fitting process along with the mechanisms for ion beam production and hard x-ray emission. To show the important role of the anomalous resistance, the duration of the current drop was discussed.

  19. Type IV Collagen Controls the Axogenesis of Cerebellar Granule Cells by Regulating Basement Membrane Integrity in Zebrafish.

    PubMed

    Takeuchi, Miki; Yamaguchi, Shingo; Yonemura, Shigenobu; Kakiguchi, Kisa; Sato, Yoshikatsu; Higashiyama, Tetsuya; Shimizu, Takashi; Hibi, Masahiko

    2015-10-01

    Granule cells (GCs) are the major glutamatergic neurons in the cerebellum, and GC axon formation is an initial step in establishing functional cerebellar circuits. In the zebrafish cerebellum, GCs can be classified into rostromedial and caudolateral groups, according to the locations of their somata in the corresponding cerebellar lobes. The axons of the GCs in the caudolateral lobes terminate on crest cells in the dorsal hindbrain, as well as forming en passant synapses with Purkinje cells in the cerebellum. In the zebrafish mutant shiomaneki, the caudolateral GCs extend aberrant axons. Positional cloning revealed that the shiomaneki (sio) gene locus encodes Col4a6, a subunit of type IV collagen, which, in a complex with Col4a5, is a basement membrane (BM) component. Both col4a5 and col4a6 mutants displayed similar abnormalities in the axogenesis of GCs and retinal ganglion cells (RGCs). Although type IV collagen is reported to control axon targeting by regulating the concentration gradient of an axonal guidance molecule Slit, Slit overexpression did not affect the GC axons. The structure of the BM surrounding the tectum and dorsal hindbrain was disorganized in the col4a5 and col4a6 mutants. Moreover, the abnormal axogenesis of the caudolateral GCs and the RGCs was coupled with aberrant BM structures in the type IV collagen mutants. The regrowth of GC axons after experimental ablation revealed that the original and newly formed axons displayed similar branching and extension abnormalities in the col4a6 mutants. These results collectively suggest that type IV collagen controls GC axon formation by regulating the integrity of the BM, which provides axons with the correct path to their targets. PMID:26451951

  20. Fatal Peritoneal Bleeding Following Embolization of a Carotid-Cavernous Fistula in Ehlers-Danlos Syndrome Type IV

    SciTech Connect

    Usinskiene, Jurgita; Mazighi, Mikael; Bisdorff, Annouk; Houdart, Emmanuel

    2006-12-15

    We report the case of a 25-year-old woman treated for a spontaneous carotid-cavernous fistula in a context of Ehlers-Danlos syndrome type IV. Embolization with a transvenous approach was achieved without complications; however, the patient died 72 hr later of massive intraperitoneal bleeding. At autopsy, no lesion of the digestive arteries was identified. Possible causes of this bleeding are discussed.

  1. Type IV Collagen Controls the Axogenesis of Cerebellar Granule Cells by Regulating Basement Membrane Integrity in Zebrafish

    PubMed Central

    Takeuchi, Miki; Yamaguchi, Shingo; Yonemura, Shigenobu; Kakiguchi, Kisa; Sato, Yoshikatsu; Higashiyama, Tetsuya; Shimizu, Takashi; Hibi, Masahiko

    2015-01-01

    Granule cells (GCs) are the major glutamatergic neurons in the cerebellum, and GC axon formation is an initial step in establishing functional cerebellar circuits. In the zebrafish cerebellum, GCs can be classified into rostromedial and caudolateral groups, according to the locations of their somata in the corresponding cerebellar lobes. The axons of the GCs in the caudolateral lobes terminate on crest cells in the dorsal hindbrain, as well as forming en passant synapses with Purkinje cells in the cerebellum. In the zebrafish mutant shiomaneki, the caudolateral GCs extend aberrant axons. Positional cloning revealed that the shiomaneki (sio) gene locus encodes Col4a6, a subunit of type IV collagen, which, in a complex with Col4a5, is a basement membrane (BM) component. Both col4a5 and col4a6 mutants displayed similar abnormalities in the axogenesis of GCs and retinal ganglion cells (RGCs). Although type IV collagen is reported to control axon targeting by regulating the concentration gradient of an axonal guidance molecule Slit, Slit overexpression did not affect the GC axons. The structure of the BM surrounding the tectum and dorsal hindbrain was disorganized in the col4a5 and col4a6 mutants. Moreover, the abnormal axogenesis of the caudolateral GCs and the RGCs was coupled with aberrant BM structures in the type IV collagen mutants. The regrowth of GC axons after experimental ablation revealed that the original and newly formed axons displayed similar branching and extension abnormalities in the col4a6 mutants. These results collectively suggest that type IV collagen controls GC axon formation by regulating the integrity of the BM, which provides axons with the correct path to their targets. PMID:26451951

  2. Antimicrobial peptide inhibition of fungalysin proteases that target plant type 19 Family IV defense chitinases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cereal crops and other plants produce secreted seed chitinases that reduce pathogenic infection, most likely by targeting the fungal chitinous cell wall. We have shown that corn (Zea mays) produces three GH family 19, plant class IV chitinases, that help in protecting the plant against Fusarium and ...

  3. Anomalous law of cooling

    SciTech Connect

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.

    2015-03-14

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  4. Anomalous law of cooling.

    PubMed

    Lapas, Luciano C; Ferreira, Rogelma M S; Rubí, J Miguel; Oliveira, Fernando A

    2015-03-14

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics. PMID:25770525

  5. Anomalous law of cooling

    NASA Astrophysics Data System (ADS)

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.

    2015-03-01

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  6. Determination of PCBs in Rocky Flats Type IV waste sludge by gas chromatography/electron capture detection

    SciTech Connect

    Parish, K.J.; Applegate, D.V.; Boparai, A.S.; Reedy, G.T.

    1993-12-01

    Type IV Rocky Flats Plant (RFP) radioactive sludge samples must be evaluated for polychlorinated biphenyl (PCB) content before disposal. The Type IV sludge consists of organic solvents, degreasers, cutting oils, and transuranic (TRU) waste mixed with calcium silicate (MicroCel E{reg_sign}) and Oil Dri{reg_sign} to form a grease or paste-like material. For laboratory studies a nonradioactive simulated Type IV RFP sludge was prepared having a composition similar to that expected from field samples. A simplified method was developed for extraction, purification and analysis of PCBs using samples of simulated sludge spiked with Aroclors 1254 and 1260 (reports provided to Argonne indicated Aroclors 1254 and 1260 as the most likely PCB contaminants in RFP sludge samples). The developed method was compared to the Environmental Protection Agency (EPA) accepted SW-846 method for analysis of PCBs (Method 8081). The accuracy and precision data were found to be similar for the two methods. The developed method was also tested with samples of simulated sludge spiked with Pu (in solid and solution forms). Reduction of radioactivity in final extract versus in the spike sample ranged from a factor of 10{sup 5} to 10{sup 7}.

  7. Glomerular basement membrane expansion in passive Heymann nephritis. Absence of increased synthesis of type IV collagen, laminin, or fibronectin.

    PubMed Central

    Fogel, M. A.; Boyd, C. D.; Leardkamolkarn, V.; Abrahamson, D. R.; Minto, A. W.; Salant, D. J.

    1991-01-01

    The distribution and synthetic rate of glomerular basement membrane components was examined in the Passive Heymann Nephritis model of experimental membranous nephropathy. The extensive tissue injury that developed included subepithelial electron-dense deposits, podocyte foot process effacement, and expansion of the glomerular basement membrane. Levels of mRNA for type IV collagen, laminin, and fibronectin from isolated glomeruli was quantitated by slot-blot analysis and showed no change in experimental animals as compared to controls at either 1 week, 3 weeks, or 3 months after disease induction. Immunoelectron microscopy with gold-labeled anti-laminin IgG revealed no difference in the number of particles bound to the glomerular basement membrane of experimental animals and controls. Immunofluorescence with both type IV collagen antisera and anti-laminin antibody showed no difference in the intensity or pattern of staining. Despite extensive glomerular damage and glomerular basement membrane thickening, no evidence was found for either an increase in the synthetic rate of type IV collagen, laminin, or fibronectin or for an accumulation of basement membrane laminin within the damaged glomeruli. Alternate processes, such as diminished density of matrix components or accumulation of other unmeasured matrix constituents, presumably account for the expansion of the glomerular basement membrane seen in experimental membranous nephropathy. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:1992771

  8. Multiple strokes and bilateral carotid dissections: a fulminant case of newly diagnosed Ehlers-Danlos syndrome type IV.

    PubMed

    Dohle, C; Baehring, J M

    2012-07-15

    Ehlers-Danlos Syndrome is a rare group of inheritable disorders resulting in abnormal collagen production, leading to skin fragility, joint hypermobility and easy bruising. Six major subtypes have been identified, of which Type IV most often leads to neurovascular complications, may lead to inner organ rupture and overall has the worst prognosis. Early recognition followed by genetic testing is key, since this diagnosis will guide decision making in the management of complications, influence the choice of antiplatelet medications versus anticoagulants and allow for potentially affected family members to be identified, undergo genetic testing and reproductive counseling. We here report the case of a 50 year old woman with a fulminant presentation of Ehlers Danlos Syndrome Type IV, including bilateral carotid and vertebral artery dissection, multiple strokes and liver rupture. Of note, this patient did not have a known history or obvious clinical features of connective tissue disease. Genetic testing confirmed the diagnosis. Review of her family history revealed multiple family members with a history of aortic dissection or aneurysm rupture. This case illustrates that Ehlers Danlos Syndrome Type IV is an important differential diagnosis even in adult patients without a known history of connective tissue disease and no prior complications. PMID:22559935

  9. Genomic and Gene-Expression Comparisons among Phage-Resistant Type-IV Pilus Mutants of Pseudomonas syringae pathovar phaseolicola

    PubMed Central

    Sistrom, Mark; Park, Derek; O’Brien, Heath E.; Wang, Zheng; Guttman, David S.; Townsend, Jeffrey P.; Turner, Paul E.

    2015-01-01

    Pseudomonas syringae pv. phaseolicola (Pph) is a significant bacterial pathogen of agricultural crops, and phage Φ6 and other members of the dsRNA virus family Cystoviridae undergo lytic (virulent) infection of Pph, using the type IV pilus as the initial site of cellular attachment. Despite the popularity of Pph/phage Φ6 as a model system in evolutionary biology, Pph resistance to phage Φ6 remains poorly characterized. To investigate differences between phage Φ6 resistant Pph strains, we examined genomic and gene expression variation among three bacterial genotypes that differ in the number of type IV pili expressed per cell: ordinary (wild-type), non-piliated, and super-piliated. Genome sequencing of non-piliated and super-piliated Pph identified few mutations that separate these genotypes from wild type Pph–and none present in genes known to be directly involved in type IV pilus expression. Expression analysis revealed that 81.1% of gene ontology (GO) terms up-regulated in the non-piliated strain were down-regulated in the super-piliated strain. This differential expression is particularly prevalent in genes associated with respiration—specifically genes in the tricarboxylic acid cycle (TCA) cycle, aerobic respiration, and acetyl-CoA metabolism. The expression patterns of the TCA pathway appear to be generally up and down-regulated, in non-piliated and super-piliated Pph respectively. As pilus retraction is mediated by an ATP motor, loss of retraction ability might lead to a lower energy draw on the bacterial cell, leading to a different energy balance than wild type. The lower metabolic rate of the super-piliated strain is potentially a result of its loss of ability to retract. PMID:26670219

  10. A novel arctigenin-containing latex glove prevents latex allergy by inhibiting type I/IV allergic reactions.

    PubMed

    Wang, Yong-Xin; Xue, Dan-Ting; Liu, Meng; Zhou, Zheng-Min; Shang, Jing

    2016-03-01

    The present study aimed at developing a natural compound with anti-allergic effect and stability under latex glove manufacturing conditions and investigating whether its anti-allergic effect is maintained after its addition into the latex. The effects of nine natural compounds on growth of the RBL-2H3 cells and mouse primary spleen lymphocytes were determined using MTT assay. The compounds included glycyrrhizin, osthole, tetrandrine, tea polyphenol, catechin, arctigenin, oleanolic acid, baicalin and oxymatrine. An ELISA assay was used for the in vitro anti-type I/IV allergy screening; in this process β-hexosaminidase, histamine, and IL-4 released from RBL-2H3 cell lines and IFN-γ and IL-2 released from mouse primary spleen lymphocytes were taken as screening indices. The physical stability of eight natural compounds and the dissolubility of arctigenin, selected based on the in vitro pharnacodynamaic screening and the stability evaluation, were detected by HPLC. The in vivo pharmacodynamic confirmation of arctigenin and final latex product was evaluated with a passive cutaneous anaphylaxis (PCA) model and an allergen-specific skin response model. Nine natural compounds showed minor growth inhibition on RBL-2H3 cells and mouse primary spleen lymphocytes. Baicalin and arctigenin had the best anti-type I and IV allergic effects among the natural compounds based on the in vitro pharmacodynamic screening. Arctigenin and catechin had the best physical stability under different manufacturing conditions. Arctigenin was the selected for further evaluation and proven to have anti-type I and IV allergic effects in vivo in a dose-dependent manner. The final product of the arctigenin-containing latex glove had anti-type I and IV allergic effects in vivo which were mainly attributed to arctigenin as proved from the dissolubility results. Arctigenin showed anti-type I and IV allergic effects in vitro and in vivo, with a good stability under latex glove manufacturing conditions

  11. Hemocyte-Secreted Type IV Collagen Enhances BMP Signaling to Guide Renal Tubule Morphogenesis in Drosophila

    PubMed Central

    Bunt, Stephanie; Hooley, Clare; Hu, Nan; Scahill, Catherine; Weavers, Helen; Skaer, Helen

    2010-01-01

    Summary Details of the mechanisms that determine the shape and positioning of organs in the body cavity remain largely obscure. We show that stereotypic positioning of outgrowing Drosophila renal tubules depends on signaling in a subset of tubule cells and results from enhanced sensitivity to guidance signals by targeted matrix deposition. VEGF/PDGF ligands from the tubules attract hemocytes, which secrete components of the basement membrane to ensheath them. Collagen IV sensitizes tubule cells to localized BMP guidance cues. Signaling results in pathway activation in a subset of tubule cells that lead outgrowth through the body cavity. Failure of hemocyte migration, loss of collagen IV, or abrogation of BMP signaling results in tubule misrouting and defective organ shape and positioning. Such regulated interplay between cell-cell and cell-matrix interactions is likely to have wide relevance in organogenesis and congenital disease. PMID:20708591

  12. Anomalous output characteristic shift for the n-type lateral diffused metal-oxide-semiconductor transistor with floating P-top layer

    SciTech Connect

    Liu, Siyang; Zhang, Chunwei; Sun, Weifeng; Su, Wei; Wang, Shaorong; Ma, Shulang; Huang, Yu

    2014-04-14

    Anomalous output characteristic shift of the n-type lateral diffused metal-oxide-semiconductor transistor with floating P-top layer is investigated. It shows that the linear drain current has obvious decrease when the output characteristic of fresh device is measured for two consecutive times. The charge pumping experiments demonstrate that the decrease is not from hot-carrier degradation. The reduction of cross section area for the current flowing, which results from the squeezing of the depletion region surrounding the P-top layer, is responsible for the shift. Consequently, the current capability of this special device should be evaluated by the second measured output characteristic.

  13. Cellular localization of type I III and IV procollagen gene transcripts in normal and fibrotic human liver.

    PubMed Central

    Milani, S.; Herbst, H.; Schuppan, D.; Surrenti, C.; Riecken, E. O.; Stein, H.

    1990-01-01

    The authors have determined the cell types producing alpha 1 (I), alpha 2 (I), alpha 1 (III), and alpha 1 (IV) procollagen gene transcripts in adult human liver by in situ hybridization with [35S]-labeled RNA probes. The liver specimens comprised a total of 20 biopsies with normal histology and biopsies with fibrosis or cirrhosis at different clinical stages and of heterogeneous origins. In normal liver, procollagen type I, III, and IV transcripts were detected in stromal and vascular mesenchymal cells of portal tracts and central veins, as well as in some perisinusoidal cells of the lobule. In fibrotic liver, increased levels of these procollagen mRNAs were observed in the same locations, and particularly enhanced in stromal cells of fibrotic septa and portal tracts, as well as in perisinusoidal cells. Expression of alpha 1 (IV) procollagen RNA was additionally found in some vascular endothelial and bile duct epithelial cells. Although previously suggested as the major source of liver collagens, hepatocytes showed no significant procollagen transcript levels in any of our samples. Thus, procollagen synthesis does not appear to be a function of hepatocytes, but rather of mesenchymal, endothelial, and bile duct epithelial cells in adult human liver. These findings may have implications for the development of specifically targeted antifibrotic therapies. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 PMID:2372043

  14. Anomalous Arms

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In this composite image of spiral galaxy M106 (NGC 4258), optical data from the Digitized Sky Survey is shown as yellow, radio data from the Very Large Array appears as purple, X-ray data from Chandra is coded blue, and infrared data from the Spitzer Space Telescope appears red. Two anomalous arms, which aren't visible at optical wavelengths, appear as purple and blue emission.

  15. Characterization of a recombinant C-type lectin, rCEL-IV, expressed in Escherichia coli cells using a synthetic gene.

    PubMed

    Hatakeyama, Tomomitsu; Hozawa, Takao; Hirotani, Iyo; Tsuda, Nobuaki; Kusunoki, Masami; Shiba, Kohei

    2006-03-01

    The body fluid of marine invertebrate Cucumaria echinata (Holothuroidea) contains four Ca2+-dependent galactose-specific lectins. One of these lectins, CEL-IV, is composed of a C-type carbohydrate-recognition domain homotetramer. CEL-IV exhibits higher specificity for alpha-galactosides than for beta-galactosides, while other C. echinata lectins show preferential binding of beta-galactosides. We constructed an artificial synthetic gene for recombinant CEL-IV (rCEL-IV) based on the amino acid sequence previously determined from the purified protein. rCEL-IV was expressed in Escherichia coli cells as inclusion bodies. After the refolding process, most of rCEL-IV spontaneously formed a homotetramer structure having interchain disulfide bonds. The secondary structure of rCEL-IV was similar to that of the native one, as judged by the comparison of the far UV-circular dichroism spectra of rCEL-IV and native CEL-IV (nCEL-IV). Carbohydrate-binding specificity of rCEL-IV was confirmed to be similar to that of nCEL-IV from the results of the binding-inhibition assay using liposomes composed of rabbit erythrocyte lipids. Crystals of rCEL-IV were obtained in a few days by the sitting drop vapor diffusion method. These results indicate that rCEL-IV achieved essentially correct three-dimensional structure, including the carbohydrate-binding sites, and it would be very useful for further study on the carbohydrate-recognition mechanism by mutational and X-ray crystallographic analyses. PMID:16503091

  16. Spontaneous common iliac arteries rupture in Ehlers-Danlos syndrome type IV: report of two cases and review of the literature.

    PubMed Central

    Habib, K.; Memon, M. A.; Reid, D. A.; Fairbrother, B. J.

    2001-01-01

    Two patients with previously undiagnosed Ehlers-Danlos syndrome type IV (EDS IV) presented acutely with clinical features suggestive of hypovolemic shock. Emergency laparotomies in both of them revealed spontaneous rupture of the common iliac arteries. The clinical features, operative findings, surgical approach, outcome and implications are discussed. Images Figure 1 Figure 2 Figure 3 PMID:11320937

  17. Bone mineral density in MPS IV A (Morquio syndrome type A).

    PubMed

    Kecskemethy, Heidi H; Kubaski, Francyne; Harcke, H T; Tomatsu, Shunji

    2016-02-01

    Mucopolysaccharidosis IV A (MPS IV A), Morquio A, is caused by deficiency in lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS), which is responsible for the catabolism of the glycosaminoglycans (GAGs) keratan sulfate (KS) and chondroitin 6-sulfate (C6S). Accumulation of GAGs results in disrupted cartilage formation and skeletal dysplasia. In this prospective cross-sectional study, bone mineral density (BMD) of the whole body (WB), lumbar spine (LS), and lateral distal femur (LDF) was acquired by dual-energy X-ray absorptiometry (DXA) on patients with MPS IV A. Functional abilities, medical history, Tanner score, and laboratory results were reviewed. Age and sex-matched norms were used to calculate Z-scores. Participants included 18 patients (13 females; 16 were unrelated) with a mean age of 21.4years (3.3 to 40.8years). While every patient was able to bear weight, 9 were full-time ambulators. Whole-body DXA could be obtained on only 6 patients (5 full-time ambulators) because of respiratory compromise caused by the position, presence of hardware, or positioning difficulties. Mean WB Z-score was -2.0 (range-0.3 to -4.1). Technical issues invalidating LS DXA in 8 patients included kyphosis at the thoracolumbar junction resulting in overlap of vertebrae in the posterior-anterior view. Mean LS BMD Z-score in full-time ambulators was -3.4 (range-1.6 to -5.0) and in the non-/partial ambulator was -4.0 (-3.7 to -4.2). Lateral distal femur BMD was acquired on every patient, and average Z-scores were -2 or less at all sites; full-time ambulators exhibited higher BMD. In conclusion, the LDF proved to be the most feasible site to measure in patients with MPS IV A. The higher LDF values in ambulators suggest this should be a consideration in promoting bone health for this group. PMID:26670863

  18. Role of α1 and α2 chains of type IV collagen in early fibrotic lesions of idiopathic interstitial pneumonias and migration of lung fibroblasts.

    PubMed

    Urushiyama, Hirokazu; Terasaki, Yasuhiro; Nagasaka, Shinya; Terasaki, Mika; Kunugi, Shinobu; Nagase, Takahide; Fukuda, Yuh; Shimizu, Akira

    2015-08-01

    Early fibrotic lesions are thought to be the initial findings of fibrogenesis in idiopathic interstitial pneumonias, but little is known about their properties. Type IV collagen comprises six gene products, α1-α6, and although it is known as a major basement membrane component, its abnormal deposition is seen in fibrotic lesions of certain organs. We studied the expression of type I and III collagen and all α chains of type IV collagen in lung specimens from patients with usual interstitial pneumonia (UIP) or organizing pneumonia (OP) via immunohistochemistry. With cultured lung fibroblasts, we analyzed the expression and function of all α chains of type IV collagen via immunohistochemistry, western blotting, real-time quantitative PCR, and a Boyden chamber migration assay after the knockdown of α1 and α2 chains. Although we observed type I and III collagens in early fibrotic lesions of both UIP and OP, we found type IV collagen, especially α1 and α2 chains, in early fibrotic lesions of UIP but not OP. Fibroblasts enhanced the expression of α1 and α2 chains of type IV collagen after transforming growth factor-β1 stimulation. Small interfering RNA against α1 and α2 chains increased fibroblast migration, with upregulated phosphorylation of focal adhesion kinase (FAK), and adding medium containing fibroblast-produced α1 and α2 chains reduced the increased levels of fibroblast migration and phosphorylation of FAK. Fibroblasts in OP were positive for phosphorylated FAK but fibroblasts in UIP were not. These results suggest that fibroblasts in UIP with type IV collagen deposition, especially α1 and α2 chains, have less ability to migrate from early fibrotic lesions than fibroblasts in OP without type IV collagen deposition. Thus, type IV collagen deposition in early fibrotic lesions of UIP may be implicated in refractory pathophysiology including migration of lesion fibroblasts via a FAK pathway. PMID:26006016

  19. T346Hunter: A Novel Web-Based Tool for the Prediction of Type III, Type IV and Type VI Secretion Systems in Bacterial Genomes

    PubMed Central

    Martínez-García, Pedro Manuel; Ramos, Cayo; Rodríguez-Palenzuela, Pablo

    2015-01-01

    T346Hunter (Type Three, Four and Six secretion system Hunter) is a web-based tool for the identification and localisation of type III, type IV and type VI secretion systems (T3SS, T4SS and T6SS, respectively) clusters in bacterial genomes. Non-flagellar T3SS (NF-T3SS) and T6SS are complex molecular machines that deliver effector proteins from bacterial cells into the environment or into other eukaryotic or prokaryotic cells, with significant implications for pathogenesis of the strains encoding them. Meanwhile, T4SS is a more functionally diverse system, which is involved in not only effector translocation but also conjugation and DNA uptake/release. Development of control strategies against bacterial-mediated diseases requires genomic identification of the virulence arsenal of pathogenic bacteria, with T3SS, T4SS and T6SS being major determinants in this regard. Therefore, computational methods for systematic identification of these specialised machines are of particular interest. With the aim of facilitating this task, T346Hunter provides a user-friendly web-based tool for the prediction of T3SS, T4SS and T6SS clusters in newly sequenced bacterial genomes. After inspection of the available scientific literature, we constructed a database of hidden Markov model (HMM) protein profiles and sequences representing the various components of T3SS, T4SS and T6SS. T346Hunter performs searches of such a database against user-supplied bacterial sequences and localises enriched regions in any of these three types of secretion systems. Moreover, through the T346Hunter server, users can visualise the predicted clusters obtained for approximately 1700 bacterial chromosomes and plasmids. T346Hunter offers great help to researchers in advancing their understanding of the biological mechanisms in which these sophisticated molecular machines are involved. T346Hunter is freely available at http://bacterial-virulence-factors.cbgp.upm.es/T346Hunter. PMID:25867189

  20. Formation Mechanism of Type IV Failure in High Cr Ferritic Heat-Resistant Steel-Welded Joint

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Tsukamoto, S.; Shirane, T.; Abe, F.

    2013-10-01

    The mechanism of type IV failure has been investigated by using a conventional 9Cr ferritic heat-resistant steel Gr.92. In order to clarify the main cause of type IV failure, different heat treatments were performed on the base metal in order to change the prior austenite grain (PAG) size and precipitate distribution after applying the heat-affected zone (HAZ) simulated thermal cycle at the peak temperature of around A c3 ( A c3 HAZ thermal cycle) and postweld heat treatment (PWHT). The microstructural evolution during the A c3 HAZ thermal cycle and PWHT was investigated by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), electron probe microanalysis (EPMA), and transmission electron microscope (TEM). It was found that M23C6 carbides were scarcely precipitated at the newly formed fine PAG, block, and lath boundaries in A c3 HAZ-simulated Gr.92, because the carbide forming elements such as Cr and C were segregated at the former PAG and block boundaries of the base metal. On the other hand, if all the boundaries were covered by sufficient M23C6 carbides by homogenization of the alloying elements prior to applying the HAZ thermal cycle, the creep strength was much improved even if the fine PAG was formed. From these results, it is concluded that fine-grained microstructure cannot account for the occurrence of type IV failure, and it only has a small effect during long-term creep. The most important factor is the precipitate formation behavior at various boundaries. Without sufficient boundary strengthening by precipitates, the microstructure of A c3 HAZ undergoes severe changes even during PWHT and causes premature failure during creep.

  1. Megakaryocytes contribute to the bone marrow-matrix environment by expressing fibronectin, type IV collagen and laminin

    PubMed Central

    Malara, Alessandro; Currao, Manuela; Gruppi, Cristian; Celesti, Giuseppe; Viarengo, Gianluca; Buracchi, Chiara; Laghi, Luigi; Kaplan, David L.; Balduini, Alessandra

    2014-01-01

    Megakaryocytes associate with the bone marrow vasculature where they convert their cytoplasm into proplatelets that protrude through the vascular endothelium into the lumen and release platelets. The extracellular matrix (ECM) microenvironment plays a critical role in regulating these processes. In this work we demonstrate that, among bone marrow ECM components, fibronectin, type IV collagen and laminin are the most abundant around bone marrow sinusoids and constitute a peri-cellular matrix surrounding megakaryocytes. Most importantly, we report, for the first time, that megakaryocytes express components of the basement membrane and that these molecules contribute to the regulation of megakaryocyte development and bone marrow ECM homeostasis both in vitro and in vivo. In vitro, fibronectin induced a three-fold increase in the proliferation rate of mouse hematopoietic stem cells leading to higher megakaryocyte output with respect to cells treated only with thrombopoietin or other matrices. However, megakaryocyte ploidy level in fibronectin-treated cultures was significantly reduced. Stimulation with type IV collagen resulted in a 1.4-fold increase in megakaryocyte output, while all tested matrices supported proplatelet formation to a similar extent in megakaryocytes derived from fetal liver progenitor cells. In vivo, megakaryocyte expression of fibronectin and basement membrane components was up-regulated during bone marrow reconstitution upon 5-fluorouracil induced myelosuppression, while only type IV collagen resulted up-regulated upon induced thrombocytopenia. In conclusion, this work demonstrates that ECM components impact megakaryocyte behavior differently during their differentiation and highlights a new role for megakaryocyte as ECM-producing cells for the establishment of cell niches during bone marrow regeneration. PMID:24357118

  2. Proteinuria in passive Heymann nephritis is associated with lipid peroxidation and formation of adducts on type IV collagen.

    PubMed Central

    Neale, T J; Ojha, P P; Exner, M; Poczewski, H; Rüger, B; Witztum, J L; Davis, P; Kerjaschki, D

    1994-01-01

    Passive Heymann nephritis (PHN) is a model of human membranous nephropathy that is characterized by formation of granular subepithelial immune deposits in the glomerular capillary wall which results in complement activation. This is causally related to damage of the filtration barrier and subsequent proteinuria. The local accumulation of injurious reactive oxygen species (ROS) is a major effector mechanism in PHN. ROS may induce tissue damage by initiating lipid peroxidation (LPO). In turn, this leads to adduct formation between breakdown products of LPO with structural proteins, such as formation of malondialdehyde (MDA) or 4-hydroxynonenal-lysine adducts. To examine the role of LPO in the development of proteinuria we have localized MDA and 4-hydroxynonenal-lysine adducts in glomeruli of PHN rats by immunofluorescence microscopy, using specific monoclonal antibodies. By immunogold electron microscopy, MDA adducts were localized to cytoplasmic vesicles and cell membranes of glomerular epithelial cells, to the glomerular basement membrane (GBM), and also to immune deposits. Type IV collagen was specifically identified as being modified by MDA adducts, using a variety of techniques. Collagenase pretreatment of GBM extracts indicated that the NC-1 domain of type IV collagen was a site of adduct formation. When LPO was inhibited by pretreatment of PHN rats with the antioxidant probucol, proteinuria was reduced by approximately 85%, and glomerular immunostaining for dialdehyde adducts was markedly reduced, even though the formation of immune deposits was not affected. By contrast, lowering of the serum cholesterol levels had no influence on the development of proteinuria. These findings are consistent with the premise that ROS-induced glomerular injury in PHN involves LPO and that this results not only in damage of cell membranes but in modification of type IV collagen in the GBM as well. The close temporal correlation of the occurrence of LPO with proteinuria and the

  3. Characterization and transcriptional analysis of two gene clusters for type IV secretion machinery in Wolbachia of Armadillidium vulgare.

    PubMed

    Félix, Christine; Pichon, Samuel; Braquart-Varnier, Christine; Braig, Henk; Chen, Lanming; Garrett, Roger A; Martin, Gilbert; Grève, Pierre

    2008-01-01

    Wolbachia are maternally inherited alpha-proteobacteria that induce feminization of genetic males in most terrestrial crustacean isopods. Two clusters of vir genes for a type IV secretion machinery have been identified at two separate loci and characterized for the first time in a feminizing Wolbachia. Furthermore, we demonstrated that these operons are transcriptionally active in ovaries and in all other tissues tested, suggesting that T4SS has a significant role in Wolbachia biology. These observations and the identification of homologous vir genes in Wolbachia strains infecting insects or nematodes show that vir genes are conserved among Wolbachia strains whatever the phenotype induced by the bacteria. PMID:18582562

  4. 2- and 3-substituted imidazo[1,2-a]pyrazines as inhibitors of bacterial type IV secretion

    PubMed Central

    Sayer, James R.; Walldén, Karin; Pesnot, Thomas; Campbell, Frederick; Gane, Paul J.; Simone, Michela; Koss, Hans; Buelens, Floris; Boyle, Timothy P.; Selwood, David L.; Waksman, Gabriel; Tabor, Alethea B.

    2014-01-01

    A novel series of 8-amino imidazo[1,2-a]pyrazine derivatives has been developed as inhibitors of the VirB11 ATPase HP0525, a key component of the bacterial type IV secretion system. A flexible synthetic route to both 2- and 3-aryl substituted regioisomers has been developed. The resulting series of imidazo[1,2-a]pyrazines has been used to probe the structure–activity relationships of these inhibitors, which show potential as antibacterial agents. PMID:25438770

  5. The N. gonorrhoeae type IV pilus stimulates mechanosensitive pathways and cytoprotection through a pilT-dependent mechanism.

    PubMed

    Howie, Heather L; Glogauer, Michael; So, Magdalene

    2005-04-01

    The Neisseria gonorrhoeae type IV pilus is a retractile appendage that can generate forces near 100 pN. We tested the hypothesis that type IV pilus retraction influences epithelial cell gene expression by exerting tension on the host membrane. Wild-type and retraction-defective bacteria altered the expression of an identical set of epithelial cell genes during attachment. Interestingly, pilus retraction, per se, did not regulate novel gene expression but, rather, enhanced the expression of a subset of the infection-regulated genes. This is accomplished through mitogen-activated protein kinase activation and at least one other undefined stress-activated pathway. These results can be reproduced by applying artificial force on the epithelial membrane, using a magnet and magnetic beads. Importantly, this retraction-mediated signaling increases the ability of the cell to withstand apoptotic signals triggered by infection. We conclude that pilus retraction stimulates mechanosensitive pathways that enhance the expression of stress-responsive genes and activate cytoprotective signaling. A model for the role of pilus retraction in influencing host cell survival is presented. PMID:15769184

  6. The N. gonorrhoeae Type IV Pilus Stimulates Mechanosensitive Pathways and Cytoprotection through a pilT-Dependent Mechanism

    PubMed Central

    2005-01-01

    The Neisseria gonorrhoeae type IV pilus is a retractile appendage that can generate forces near 100 pN. We tested the hypothesis that type IV pilus retraction influences epithelial cell gene expression by exerting tension on the host membrane. Wild-type and retraction-defective bacteria altered the expression of an identical set of epithelial cell genes during attachment. Interestingly, pilus retraction, per se, did not regulate novel gene expression but, rather, enhanced the expression of a subset of the infection-regulated genes. This is accomplished through mitogen-activated protein kinase activation and at least one other undefined stress-activated pathway. These results can be reproduced by applying artificial force on the epithelial membrane, using a magnet and magnetic beads. Importantly, this retraction-mediated signaling increases the ability of the cell to withstand apoptotic signals triggered by infection. We conclude that pilus retraction stimulates mechanosensitive pathways that enhance the expression of stress-responsive genes and activate cytoprotective signaling. A model for the role of pilus retraction in influencing host cell survival is presented. PMID:15769184

  7. Identification of a type IV secretion substrate of Brucella abortus that participates in the early stages of intracellular survival.

    PubMed

    Döhmer, Peter H; Valguarnera, Ezequiel; Czibener, Cecilia; Ugalde, Juan E

    2014-03-01

    Brucella abortus, the aetiological agent of bovine brucellosis, is an intracellular pathogen whose virulence is completely dependent on a type IV secretion system. This secretion system translocates effector proteins into the host cell to modulate the intracellular fate of the bacterium in order to establish a secure niche were it actively replicates. Although much has been done in understanding how this secretion system participates in the virulence process, few effector proteins have been identified to date. We describe here the identification of a type IV secretion substrate (SepA) that is only present in Brucella spp. and has no detectable homology to known proteins. This protein is secreted in a virB-dependent manner in a two-step process involving a periplasmic intermediate and secretion is necessary for its function. The deletion mutant showed a defect in the early stages of intracellular replication in professional and non-professional phagocytes although it invades the cells more efficiently than the wild-type parental strain. Our results indicate that, even though the mutant was more invasive, it had a defect in excluding the lysosomal marker Lamp-1 and was inactivated more efficiently during the early phases of the intracellular life cycle. PMID:24119283

  8. A rationalization of the Type IV loading dependence in the Kärger-Pfeifer classification of self-diffusivities

    SciTech Connect

    Krishna, Rajamani; van Baten, Jasper M.

    2011-01-08

    Kärger and Pfeifer (1987) have listed five different types of dependencies of the self-diffusivities, Di,self, on the loading, Θl, of guest molecules in zeolites. Of these five types, the Type IV dependence is particularly intriguing because it displays a maximum in the Di,self - Θl dependence for FAU zeolite. On the basis of published experimental data, and molecular simulations, for a variety of guest–host combinations we present arguments to suggest that the reasons for the curious maximum can be traced to molecular clustering. The clustering can be caused due to hydrogen bonding effects as is the case for methanol diffusion in NaY, or due to the temperatures being lower than the critical temperature, Tc.

  9. The 1.9-A crystal structure of the noncollagenous (NC1) domain of human placenta collagen IV shows stabilization via a novel type of covalent Met-Lys cross-link.

    PubMed

    Than, Manuel E; Henrich, Stefan; Huber, Robert; Ries, Albert; Mann, Karlheinz; Kühn, Klaus; Timpl, Rupert; Bourenkov, Gleb P; Bartunik, Hans D; Bode, Wolfram

    2002-05-14

    Triple-helical collagen IV protomers associate through their N- and C-termini forming a three-dimensional network, which provides basement membranes with an anchoring scaffold and mechanical strength. The noncollagenous (NC1) domain of the C-terminal junction between two adjacent collagen IV protomers from human placenta was crystallized and its 1.9-A structure was solved by multiple anomalous diffraction (MAD) phasing. This hexameric NC1 particle is composed of two trimeric caps, which interact through a large planar interface. Each cap is formed by two alpha 1 fragments and one alpha 2 fragment with a similar previously uncharacterized fold, segmentally arranged around an axial tunnel. Each monomer chain folds into two structurally very similar subdomains, which each contain a finger-like hairpin loop that inserts into a six-stranded beta-sheet of the neighboring subdomain of the same or the adjacent chain. Thus each trimer forms a quite regular, but nonclassical, sixfold propeller. The trimer-trimer interaction is further stabilized by a previously uncharacterized type of covalent cross-link between the side chains of a Met and a Lys residue of the alpha 1 and alpha 2 chains from opposite trimers, explaining previous findings of nonreducible cross-links in NC1. This structure provides insights into NC1-related diseases such as Goodpasture and Alport syndromes. PMID:12011424

  10. Inhibitors of cyclic nucleotide phosphodiesterase isozymes type-III and type-IV suppress mitogenesis of rat mesangial cells.

    PubMed Central

    Matousovic, K; Grande, J P; Chini, C C; Chini, E N; Dousa, T P

    1995-01-01

    We studied interactions between the mitogen-activated protein kinase (MAPK) signalling pathway and cAMP-protein kinase (PKA) signaling pathway in regulation of mitogenesis of mesangial cells (MC) determined by [3H]thymidine incorporation, with or without added EGF. Forskolin or dibutyryl cAMP strongly (by 60-70%) inhibited [3H]thymidine incorporation into MC. Cilostamide, lixazinone or cilostazol selective inhibitors of cAMP-phosphodiesterase (PDE) isozyme PDE-III, inhibited mitogenesis to similar extent as forskolin and DBcAMP and activated in situ PKA, but without detectable increase in cAMP levels. Cilostamide and cilostazol were more than three times more effective at inhibiting mesangial mitogenesis than rolipram and denbufylline, inhibitors of isozyme PDE-IV, even though PDE-IV was two times more abundant in MC than was PDE-III. On the other hand, when incubated with forskolin, rolipram-enhanced cAMP accumulation was far greater (10-100x) than with cilostamide. EGF increased MAPK activity (+300%); PDE isozyme inhibitors which suppressed mitogenesis also inhibited MAPK. PDE isozyme inhibitors also suppressed PDGF-stimulated MC proliferation. We conclude that cAMP inhibits the mitogen-dependent MAPK-signaling pathway probably by decreasing the activity of Raf-1 due to PKA-catalyzed phosphorylation. Further, we surmise that minor increase in the cAMP pool metabolized by PDE-III is intimately related to regulation of mesangial proliferation. Thus, PDE isozyme inhibitors have the potential to suppress MC proliferation by a focused effect upon signaling pathways. Images PMID:7615811

  11. Investigation of enhanced hemocompatibility and tissue compatibility associated with multi-functional coating based on hyaluronic acid and Type IV collagen.

    PubMed

    Li, Jingan; Zhang, Kun; Ma, Wenyong; Wu, Feng; Yang, Ping; He, Zikun; Huang, Nan

    2016-09-01

    The biocompatibility of cardiovascular devices has always been considered crucial for their clinical efficacy. Therefore, a biofunctional coating composed of Type IV collagen (CoIV) and hyaluronan (HA) was previously fabricated onto the titanium (Ti) substrate for the application of promoting vascular smooth muscle cell contractile phenotype and improving surface endothelialization. However, the anti-inflammation property, blood compatibility and in vivo tissue compatibility of the HA/CoIV coating, as paramount consideration of cardiovascular materials surface coating, have not been investigated. Thus, in this study, the three crucial properties of the HA/CoIV coating were tested. The platelet adhesion/activation test and the dynamic whole blood experiment implied that the HA/CoIV coating had better blood compatibility compared with Ti substrate and pure CoIV coating. The macrophage adhesion/activation and inflammatory cytokine release (tumor necrosis factor-alpha and interleukin-1) results indicated that the HA/CoIV coating could significantly improve the anti-inflammation property of the Ti substrate. The in vivo implantation of SD rats for 3 weeks' results demonstrated that the HA/CoIV coating caused milder tissue response. All these results suggested that the multi-functional HA/CoIV coating possessed good biocompatibility. This research is anticipated to be potentially applied for the surface modification of cardiovascular stents. PMID:27252884

  12. Investigation of enhanced hemocompatibility and tissue compatibility associated with multi-functional coating based on hyaluronic acid and Type IV collagen

    PubMed Central

    Li, Jingan; Zhang, Kun; Ma, Wenyong; Wu, Feng; Yang, Ping; He, Zikun; Huang, Nan

    2016-01-01

    The biocompatibility of cardiovascular devices has always been considered crucial for their clinical efficacy. Therefore, a biofunctional coating composed of Type IV collagen (CoIV) and hyaluronan (HA) was previously fabricated onto the titanium (Ti) substrate for the application of promoting vascular smooth muscle cell contractile phenotype and improving surface endothelialization. However, the anti-inflammation property, blood compatibility and in vivo tissue compatibility of the HA/CoIV coating, as paramount consideration of cardiovascular materials surface coating, have not been investigated. Thus, in this study, the three crucial properties of the HA/CoIV coating were tested. The platelet adhesion/activation test and the dynamic whole blood experiment implied that the HA/CoIV coating had better blood compatibility compared with Ti substrate and pure CoIV coating. The macrophage adhesion/activation and inflammatory cytokine release (tumor necrosis factor-alpha and interleukin-1) results indicated that the HA/CoIV coating could significantly improve the anti-inflammation property of the Ti substrate. The in vivo implantation of SD rats for 3 weeks’ results demonstrated that the HA/CoIV coating caused milder tissue response. All these results suggested that the multi-functional HA/CoIV coating possessed good biocompatibility. This research is anticipated to be potentially applied for the surface modification of cardiovascular stents. PMID:27252884

  13. First Report of cfr-Carrying Plasmids in the Pandemic Sequence Type 22 Methicillin-Resistant Staphylococcus aureus Staphylococcal Cassette Chromosome mec Type IV Clone

    PubMed Central

    Shore, Anna C.; Lazaris, Alexandros; Kinnevey, Peter M.; Brennan, Orla M.; Brennan, Gráinne I.; O'Connell, Brian; Feßler, Andrea T.; Schwarz, Stefan

    2016-01-01

    Linezolid is often the drug of last resort for serious methicillin-resistant Staphylococcus aureus (MRSA) infections. Linezolid resistance is mediated by mutations in 23S rRNA and genes for ribosomal proteins; cfr, encoding phenicol, lincosamide, oxazolidinone, pleuromutilin, and streptogramin A (PhLOPSA) resistance; its homologue cfr(B); or optrA, conferring oxazolidinone and phenicol resistance. Linezolid resistance is rare in S. aureus, and cfr is even rarer. This study investigated the clonality and linezolid resistance mechanisms of two MRSA isolates from patients in separate Irish hospitals. Isolates were subjected to cfr PCR, PhLOPSA susceptibility testing, 23S rRNA PCR and sequencing, DNA microarray profiling, spa typing, pulsed-field gel electrophoresis (PFGE), plasmid curing, and conjugative transfer. Whole-genome sequencing was used for single-nucleotide variant (SNV) analysis, multilocus sequence typing, L protein mutation identification, cfr plasmid sequence analysis, and optrA and cfr(B) detection. Isolates M12/0145 and M13/0401 exhibited linezolid MICs of 64 and 16 mg/liter, respectively, and harbored identical 23S rRNA and L22 mutations, but M12/0145 exhibited the mutation in 2/6 23S rRNA alleles, compared to 1/5 in M13/0401. Both isolates were sequence type 22 MRSA staphylococcal cassette chromosome mec type IV (ST22-MRSA-IV)/spa type t032 isolates, harbored cfr, exhibited the PhLOPSA phenotype, and lacked optrA and cfr(B). They differed by five PFGE bands and 603 SNVs. Isolate M12/0145 harbored cfr and fexA on a 41-kb conjugative pSCFS3-type plasmid, whereas M13/0401 harbored cfr and lsa(B) on a novel 27-kb plasmid. This is the first report of cfr in the pandemic ST22-MRSA-IV clone. Different cfr plasmids and mutations associated with linezolid resistance in genotypically distinct ST22-MRSA-IV isolates highlight that prudent management of linezolid use is essential. PMID:26953212

  14. First Report of cfr-Carrying Plasmids in the Pandemic Sequence Type 22 Methicillin-Resistant Staphylococcus aureus Staphylococcal Cassette Chromosome mec Type IV Clone.

    PubMed

    Shore, Anna C; Lazaris, Alexandros; Kinnevey, Peter M; Brennan, Orla M; Brennan, Gráinne I; O'Connell, Brian; Feßler, Andrea T; Schwarz, Stefan; Coleman, David C

    2016-05-01

    Linezolid is often the drug of last resort for serious methicillin-resistant Staphylococcus aureus (MRSA) infections. Linezolid resistance is mediated by mutations in 23S rRNA and genes for ribosomal proteins; cfr, encoding phenicol, lincosamide, oxazolidinone, pleuromutilin, and streptogramin A (PhLOPSA) resistance; its homologue cfr(B); or optrA, conferring oxazolidinone and phenicol resistance. Linezolid resistance is rare in S. aureus, and cfr is even rarer. This study investigated the clonality and linezolid resistance mechanisms of two MRSA isolates from patients in separate Irish hospitals. Isolates were subjected to cfr PCR, PhLOPSA susceptibility testing, 23S rRNA PCR and sequencing, DNA microarray profiling, spa typing, pulsed-field gel electrophoresis (PFGE), plasmid curing, and conjugative transfer. Whole-genome sequencing was used for single-nucleotide variant (SNV) analysis, multilocus sequence typing, L protein mutation identification, cfr plasmid sequence analysis, and optrA and cfr(B) detection. Isolates M12/0145 and M13/0401 exhibited linezolid MICs of 64 and 16 mg/liter, respectively, and harbored identical 23S rRNA and L22 mutations, but M12/0145 exhibited the mutation in 2/6 23S rRNA alleles, compared to 1/5 in M13/0401. Both isolates were sequence type 22 MRSA staphylococcal cassette chromosome mec type IV (ST22-MRSA-IV)/spa type t032 isolates, harbored cfr, exhibited the PhLOPSA phenotype, and lacked optrA and cfr(B). They differed by five PFGE bands and 603 SNVs. Isolate M12/0145 harbored cfr and fexA on a 41-kb conjugative pSCFS3-type plasmid, whereas M13/0401 harbored cfr and lsa(B) on a novel 27-kb plasmid. This is the first report of cfr in the pandemic ST22-MRSA-IV clone. Different cfr plasmids and mutations associated with linezolid resistance in genotypically distinct ST22-MRSA-IV isolates highlight that prudent management of linezolid use is essential. PMID:26953212

  15. Branching enzyme activity of cultured amniocytes and chorionic villi: prenatal testing for type IV glycogen storage disease.

    PubMed Central

    Brown, B I; Brown, D H

    1989-01-01

    Although type IV glycogen storage disease (Andersen disease; McKusick 23250) is considered to be a rare, autosomally recessive disorder, of the more than 600 patients with glycogenosis identified in our laboratory by enzymatic assays, 6% have been shown to be deficient in the glycogen branching enzyme. Most of the 38 patients with type IV glycogen storage disease who are known to us have succumbed at a very early age, with the exception of one male teenager, an apparently healthy 7-year-old male, and several 5-year-old patients. Fourteen pregnancies at risk for branching enzyme deficiency have been monitored using cultured amniotic fluid cells, and four additional pregnancies have been screened using cultured chorionic villi. Essentially no branching enzyme activity was detectable in eight samples (amniocytes); activities within the control range were found in five samples (three amniocyte and two chorionic villi samples); and five samples appeared to have been derived from carriers. In two of the cases lacking branching enzyme activity, in which the pregnancies were terminated and fibroblasts were successfully cultured from the aborted fetuses, no branching enzyme activity was found. Another fetus, which was predicted by antenatal assay to be affected, was carried to term. Skin fibroblasts from this baby were deficient in branching enzyme. Pregnancies at risk for glycogen storage disease due to the deficiency of branching enzyme can be successfully monitored using either cultured chorionic villi or amniocytes. PMID:2521770

  16. ESCRT-Dependent Cell Death in a Caenorhabditis elegans Model of the Lysosomal Storage Disorder Mucolipidosis Type IV.

    PubMed

    Huynh, Julie M; Dang, Hope; Munoz-Tucker, Isabel A; O'Ketch, Marvin; Liu, Ian T; Perno, Savannah; Bhuyan, Natasha; Crain, Allison; Borbon, Ivan; Fares, Hanna

    2016-02-01

    Mutations in MCOLN1, which encodes the cation channel protein TRPML1, result in the neurodegenerative lysosomal storage disorder Mucolipidosis type IV. Mucolipidosis type IV patients show lysosomal dysfunction in many tissues and neuronal cell death. The ortholog of TRPML1 in Caenorhabditis elegans is CUP-5; loss of CUP-5 results in lysosomal dysfunction in many tissues and death of developing intestinal cells that results in embryonic lethality. We previously showed that a null mutation in the ATP-Binding Cassette transporter MRP-4 rescues the lysosomal defect and embryonic lethality of cup-5(null) worms. Here we show that reducing levels of the Endosomal Sorting Complex Required for Transport (ESCRT)-associated proteins DID-2, USP-50, and ALX-1/EGO-2, which mediate the final de-ubiquitination step of integral membrane proteins being sequestered into late endosomes, also almost fully suppresses cup-5(null) mutant lysosomal defects and embryonic lethality. Indeed, we show that MRP-4 protein is hypo-ubiquitinated in the absence of CUP-5 and that reducing levels of ESCRT-associated proteins suppresses this hypo-ubiquitination. Thus, increased ESCRT-associated de-ubiquitinating activity mediates the lysosomal defects and corresponding cell death phenotypes in the absence of CUP-5. PMID:26596346

  17. Localization of type IV collagen a 1 to a 6 chains in basement membrane during mouse molar germ development.

    PubMed

    Nagai, N; Nakano, K; Sado, Y; Naito, I; Gunduz, M; Tsujigiwa, H; Nagatsuka, H; Ninomiya, Y; Siar, C H

    2001-10-01

    The dental basement membrane (BM) putatively mediates epithelial-mesenchymal interactions during tooth morphogenesis and cytodifferentiation. Type IV collagen alpha chains, a major network-forming protein of the dental BM, was studied and results disclosed distinct expression patterns at different stages of mouse molar germ development. At the dental placode and bud stage, the BM of the oral epithelium expressed alpha 1, alpha 2, alpha 5 and alpha 6 chains while the gubernaculum dentis, in addition to the above four chains, also expressed a 4 chain. An asymmetrical expression for alpha 4, alpha 5 and alpha 6 chains was observed at the bud stage. At the early bell stage, the BM associated with the inner enamel epithelium (IEE) of molar germ expressed alpha 1, alpha 2 and alpha 4 chains while the BM of the outer enamel epithelium (OEE) expressed only alpha 1 and a 2 chains. With the onset of dentinogenesis, the collagen a chain profile of the IEE BM gradually disappeared. Howeverfrom the early to late bell stage, the gubernaculum dentis consistently expressed alpha 1, alpha 2, alpha 5 and a 6 chains resembling fetal oral mucosa. These findings suggest that stage- and position-specific distribution of type IV collagen alpha subunits occur during molar germ development and that these changes are essential for molar morphogenesis and cytodifferentiation. PMID:11732842

  18. Hepatopancreatoduodenectomy for local recurrence of cholangiocarcinoma after excision of a type IV-A congenital choledochal cyst: a case report.

    PubMed

    Yamada, Mihoko; Ebata, Tomoki; Sugawara, Gen; Igami, Tsuyoshi; Mizuno, Takashi; Shingu, Yuji; Nagino, Masato

    2016-12-01

    Surgical resection is the only curative treatment for biliary tract cancer (BTC); however, the recurrence rate remains high even after curative resection. There are limited data regarding the effectiveness of surgical resection for recurrent BTC. We report the favorable survival outcome of a patient who underwent a hepatopancreatoduodenectomy for local recurrence of cholangiocarcinoma after excision of a type IV-A congenital choledochal cyst. The patient, a 25-year-old woman, had undergone excision of a type IV-A congenital choledochal cyst with hepaticojejunostomy. The resected specimen revealed an early cholangiocarcinoma. The local recurrence at the site of anastomosis was detected 4 years and 4 months after surgery. We performed a left trisectionectomy with caudate lobectomy combined with hepatic artery and portal vein resections and a pancreaticoduodenectomy. Histological examination revealed a moderately differentiated adenocarcinoma, and the final diagnosis was recurrence of cholangiocarcinoma. There are a few reports of extensive resection for recurrence of BTC; however, aggressive surgery is possible and may offer favorable survival in selected patients. PMID:26943695

  19. A spider toxin, ω-agatoxin IV A, binds to fixed as well as living tissues: cytochemical visualization of P/Q-type calcium channels.

    PubMed

    Nakanishi, Setsuko

    2016-08-01

    ω-Agatoxin IV A, a peptidyl toxin from Agelenopsis aperta venom, selectively binds to voltage-gated P/Q-type calcium channels. ω-Agatoxin IV A has been used as a selective tool in pharmacological and electrophysiological studies. Visualization of P/Q-type calcium channels has previously been accomplished using biotin-conjugated ω-Agatoxin IV A in freshly prepared mouse cerebellar and hippocampal slices (Nakanishi et al, J. Neurosci. Res., 41: , 532, 1995). Here biotinylated ω-agatoxin IV A was applied to transcardially fixed brain slices prepared with various fixatives. ω-Agatoxin IV A did not bind to fixed tissues from P/Q-type calcium channel knockout mice, confirming that binding to normal, fixed tissues was not an artifact. Using transmission electron microscopy, locations of biotinylated ω-agatoxin IV A binding sites visualized with gold-conjugated streptavidin showed a similar pattern to those visualized with antibody. The ability of biotinylated ω-agatoxin IV A to bind to fixed tissue provides a new cytochemical technique to study molecular architecture of synapses. PMID:27095701

  20. The involvement of the PilQ secretin of type IV pili in phage infection in Ralstonia solanacearum.

    PubMed

    Narulita, Erlia; Addy, Hardian Susilo; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2016-01-22

    PilQ is a member of the secretin family of outer membrane proteins and specifically involved in type IV secretion. Here we report the effects of pilQ mutation in Ralstonia solanacearum on the host physiology including susceptibility to several phage types (Inoviridae, Podoviridae and Myoviridae). With three lines of cells, namely wild type, ΔpilQ and pilQ-complemented cells, the cell surface proteins, twitching motility and sensitivity to phages were compared. SDS-PAGE analysis revealed that the major TFP pilin (PilA) was specifically lost in pilQ mutants and was recovered in the complemented cells. Drastically inactivated twitching motility in pilQ mutants was recovered to the wild type level in the complemented cells. Several phages of different types including those of Inoviridae, Podoviridae, and Myoviridae that infect wild type cells could not form plaques on pilQ mutants but showed infectivity to pilQ-complemented cells. These results indicate that PilQ function is generally required for phage infection in R. solanacearum. PMID:26718404

  1. Heterologous assembly of type IV pili by a type II secretion system reveals the role of minor pilins in assembly initiation.

    PubMed

    Cisneros, David A; Pehau-Arnaudet, Gerard; Francetic, Olivera

    2012-11-01

    In Gram-negative bacteria, type IV pilus assembly (T4PS) and type II secretion (T2SS) systems polymerize inner membrane proteins called major pilins or pseudopilins respectively, into thin filaments. Four minor pilins are required in both systems for efficient fibre assembly. Escherichia coli K-12 has a set of T4PS assembly genes that are silent under standard growth conditions. We studied the heterologous assembly of the E. coli type IV pilin PpdD by the Klebsiella oxytoca T2SS called the Pul system. PpdD pilus assembly in this context depended on the expression of the K. oxytoca minor pseudopilin genes pulHIJK or of the E. coli minor pilin genes ppdAB-ygdB-ppdC. The E. coli minor pilins restored assembly of the major pseudopilin PulG in a pulHIJK mutant, but not the secretion of the T2SS substrate pullulanase. Thus, minor pilins and minor pseudopilins are functionally interchangeable in initiating major pilin assembly, further extending the fundamental similarities between the two systems. The data suggest that, in both systems, minor pilins activate the assembly machinery through a common self-assembly mechanism. When produced together, PulG and PpdD assembled into distinct homopolymers, establishing major pilins as key determinants of pilus elongation and structure. PMID:23006128

  2. On the Anomalous Microwave Power Dependency of both Non-Resonant and Cu2+ Resonant Microwave Absorption in a YBa2Cu3O7-δ Type Superconductor

    NASA Astrophysics Data System (ADS)

    Velter-Stefanescu, M.; Duliu, O. G.

    2007-04-01

    A ceramic high temperature superconductor [HTS] of Y-Ba-Cu-O type has been investigated at 77 K by using a standard X-band Electron Paramagnetic Resonance (EPR) configuration. At very low microwave power (< 1 mW) the non-resonant or zero field signal (ZFS) was in phase with DPPH signal, pleading for an unambiguous absorption process, but it commutes to a typical superconductor signal (i.e. opposite to DPPH signal phase) with increasing the microwave power. At the same time, Cu2+ signal appreciably changes its shape with increasing microwave power. These anomalous behaviors could be in part explained by a conventional SQUID response at microwave frequency by taking into account that the sample itself could be described by a collection of both Josephson and proximity junctions.

  3. Collagen type IV-related nephropathies in Portugal: pathogenic COL4A5 mutations and clinical characterization of 22 families.

    PubMed

    Nabais Sá, M J; Sampaio, S; Oliveira, A; Alves, S; Moura, C P; Silva, S E; Castro, R; Araújo, J A; Rodrigues, M; Neves, F; Seabra, J; Soares, C; Gaspar, M A; Tavares, I; Freitas, L; Sousa, T C; Henriques, A C; Costa, F T; Morgado, E; Sousa, F T; Sousa, J P; da Costa, A G; Filipe, R; Garrido, J; Montalban, J; Ponce, P; Alves, R; Faria, B; Carvalho, M F; Pestana, M; Carvalho, F; Oliveira, J P

    2015-11-01

    Alport syndrome (AS) is caused by pathogenic mutations in the genes encoding α3, α4 or α5 chains of collagen IV (COL4A3/COL4A4/COL4A5), resulting in hematuria, chronic renal failure (CRF), sensorineural hearing loss (SNHL) and ocular abnormalities. Mutations in the X-linked COL4A5 gene have been identified in 85% of the families (XLAS). In this study, 22 of 60 probands (37%) of unrelated Portuguese families, with clinical diagnosis of AS and no evidence of autosomal inheritance, had pathogenic COL4A5 mutations detected by Sanger sequencing and/or multiplex-ligation probe amplification, of which 12 (57%) are novel. Males had more severe and earlier renal and extrarenal complications, but microscopic hematuria was a constant finding irrespective of gender. Nonsense and splice site mutations, as well as small and large deletions, were associated with younger age of onset of SNHL in males, and with higher risk of CRF and SNHL in females. Pathogenic COL4A3 or COL4A4 mutations were subsequently identified in more than half of the families without a pathogenic mutation in COL4A5. The lower than expected prevalence of XLAS in Portuguese families warrants the use of next-generation sequencing for simultaneous COL4A3/COL4A4/COL4A5 analysis, as first-tier approach to the genetic diagnosis of collagen type IV-related nephropathies. PMID:25307721

  4. Geochemistry of Muong-Nong type tektites. IV. Selected trace element correlations

    SciTech Connect

    Koeberl, C.; Kluger, F.; Kiesl, W.

    1984-11-15

    Muong-Nong type tektites are distinct from other tektites in their shape, size, petrographical characteristics, and chemistry. Volatile elements are enriched, but other trace elements do not show large differences when compared to normal splash-form tektites. An analysis is made of nineteen Muong-Nong type tektites for 40-50 elements. Fifteen nonvolatile elements are discussed in this paper. It is shown that the Muong-Nong type tektites are very restricted in chemical composition and are almost indistinguishable from the Australasian tektites. Elemental ratios calculated from the data reported here show the same genetic connection. All elementary abundances and ratios are fully consistent with terrestrial sediments. The nonvolatile elements may record more about the conditions of the origin.

  5. TYPE II CEPHEID CANDIDATES. IV. OBJECTS FROM THE NORTHERN SKY VARIABILITY SURVEY

    SciTech Connect

    Schmidt, Edward G.

    2013-09-15

    We have obtained VR photometry of 447 Cepheid variable star candidates with declinations north of -14 Degree-Sign 30', most of which were identified using the Northern Sky Variability Survey (NSVS) data archive. Periods and other photometric properties were derived from the combination of our data with the NSVS data. Atmospheric parameters were determined for 81 of these stars from low-resolution spectra. The identification of type II Cepheids based on the data presented in all four papers in this series is discussed. On the basis of spectra, 30 type II Cepheids were identified while 53 variables were identified as cool, main sequence stars and 283 as red giants following the definitions in Paper III. An additional 30 type II Cepheids were identified on the basis of light curves. The present classifications are compared with those from the Machine-learned All Sky Automated Survey Classification Catalog for 174 stars in common.

  6. Galactic cannibalism. IV. The evidence-correlations between dynamical time scales and Bautz-Morgan type

    SciTech Connect

    McGlynn, T.A.; Ostriker, J.P.

    1980-11-01

    If the luminosity of supergiant cD galaxies in particular, and the Bautz-Morgan sequence of galaxy types in general, is produced by dynamical evolutionary processes, then one expects to find a correlation between dynamical times and ..delta..M/sub 12/, the magnitude difference between first and second brightest cluster members.

  7. Transverse Subtrochanteric Shortening Osteotomy During Cementless Total Hip Arthroplasty in Crowe Type-III or IV Developmental Dysplasia.

    PubMed

    Sofu, Hakan; Kockara, Nizamettin; Gursu, Sarper; Issin, Ahmet; Oner, Ali; Sahin, Vedat

    2015-06-01

    The purpose of this study was to review the outcomes of transverse subtrochanteric shortening osteotomy during cementless total hip arthroplasty in Crowe Type-III or IV developmental dysplasia. Seventy-three osteotomies were included in our study. Mean follow-up was 61 months. Harris hip score, leg length discrepancy, neurological status, union status of the osteotomy, and femoral component stability were the criteria for evaluation. All complications were noted. The mean Harris hip score improved from 38.6 points to 83.7 points. The mean leg length discrepancy decreased from 56.5 mm to 10.7 at the latest follow-up. The mean union time was 5.2 months. We observed 4 non-unions. Transverse subtrochanteric shortening osteotomy is an effective and reliable method in restoration of a more normal limb. PMID:25707993

  8. Unexpected presentation of a type IV laryngo-tracheo-oesophageal cleft: Anaesthetic implications of a rare case.

    PubMed

    Dwarakanath, Sanjay; Reddy, Arundathi

    2014-01-01

    Laryngo-tracheo-oesophageal cleft (LTEC) is a congenital midline defect of the posterior larynx and trachea and the anterior wall of the oesophagus. Existence of these clefts may not be apparent during pre-operative evaluation. We present a rare case of a neonate initially scheduled for tracheo-oesophageal fistula repair. Unexplained air leak in spite of placement of size 4.0 mm endotracheal tube in a 2.5 kg neonate triggered extensive intra-operative evaluation of the airway anatomy via flexible and rigid bronchoscope. A type IV LTEC with an unusual anatomy was identified that was considered surgically irreparable. This case also highlights the need for a team approach and preparedness of anaesthesiologists for a difficult airway while managing such cases. Maintenance of high degree suspicion is warranted. PMID:25624542

  9. [Morquio disease (Mucopolysaccharidosis type IV-A): clinical aspects, diagnosis and new treatment with enzyme replacement therapy].

    PubMed

    Politei, Juan; Schenone, Andrea B; Guelbert, Norberto; Fainboim, Alejandro; Szlago, Marina

    2015-08-01

    Mucopolysaccharidosis type IV-A (Morquio A disease) is an autosomal recessive lysosomal storage disease caused by mutations in the gene encoding the N-acetylgalactosamine-6-sulfate sulfatase, that results in impaired catabolism of two glycosaminoglycans, chondroitin-6-sulfate and keratan sulfate. Clinical presentations reflect a spectrum of progression from a severe phenotype to an attenuated expression. Accumulation of substrate manifests predominantly as short stature and skeletal dysplasia, including atlantoaxial instability and cervical cord compression. Other abnormalities in the visual, auditory, cardiovascular and respiratory systems can also affect individuals with Morquio disease. Elosulfase alfa showed in clinical trials in children and adults a significant and sustained improvement in endurance and urinary levels of keratan sulfate. Data from the ongoing observational, multinational Morquio A Registry Study will provide valuable information on the long-term efficacy and safety of elosulfase alfa in patients, as well as on the natural history of this very rare disease. PMID:26172013

  10. Role of Boundary Strengthening on Prevention of Type IV Failure in High Cr Ferritic Heat-Resistant Steels

    NASA Astrophysics Data System (ADS)

    Liu, Yuan; Tsukamoto, Susumu; Sawada, Kota; Abe, Fujio

    2013-10-01

    Microstructure evolution of newly developed 9Cr-3W-3Co-V, Nb steel with boron addition (B steel) has been analyzed during HAZ thermal cycle at the peak temperature of around Ac3 (Ac3 HAZ) and post-weld heat treatment (PWHT) to elucidate the prevention mechanism of type IV failure by boron addition. It was found that enhancement of the boundary strengthening by precipitates is the main reason for prevention of type IV failure by boron addition. In B steel HAZ, original austenite is reconstituted through martensitic α to γ reverse transformation during the heating and original martensite is reconstituted through martensitic transformation during cooling of the Ac3 HAZ thermal cycle. This process allows M23C6 carbides to precipitate at the prior austenite grain (PAG) and block boundaries during PWHT even if the chemical segregation of carbide forming elements exists. The effect of boundary strengthening on the creep property has also been investigated. Microstructure evolution during creep was compared among Gr.92 with different Ac3 HAZ microstructures prepared by three kinds of heat treatments and B steel. The results revealed that both the boundary length and kernel average misorientation value decreased in all samples during creep. However, this process occurred very rapidly in Ac3 HAZ simulated Gr.92, whereas it was significantly retarded in the other samples with sufficient boundary strengthening by precipitates. This result confirms that the precipitates formed at PAG and block boundaries play the most important role to stabilize the microstructure of Ac3 HAZ simulated samples during creep and prolong the creep life.

  11. Type IV Pilus Assembly in Pseudomonas aeruginosa over a Broad Range of Cyclic di-GMP Concentrations

    PubMed Central

    Jain, Ruchi; Behrens, Anna-Janina; Kaever, Volkhard

    2012-01-01

    Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen that utilizes polar type IV pili (T4P) for twitching motility and adhesion in the environment and during infection. Pilus assembly requires FimX, a GGDEF/EAL domain protein that binds and hydrolyzes cyclic di-GMP (c-di-GMP). Bacteria lacking FimX are deficient in twitching motility and microcolony formation. We carried out an extragenic suppressor screen in PA103ΔfimX bacteria to identify additional regulators of pilus assembly. Multiple suppressor mutations were mapped to PA0171, PA1121 (yfiR), and PA3703 (wspF), three genes previously associated with small-colony-variant phenotypes. Multiple independent techniques confirmed that suppressors assembled functional surface pili, though at both polar and nonpolar sites. Whole-cell c-di-GMP levels were elevated in suppressor strains, in agreement with previous studies that had shown that the disrupted genes encoded negative regulators of diguanylate cyclases. Overexpression of the regulated diguanylate cyclases was sufficient to suppress the ΔfimX pilus assembly defect, as was overexpression of an unrelated diguanylate cyclase from Caulobacter crescentus. Furthermore, under natural conditions of high c-di-GMP, PA103ΔfimX formed robust biofilms that showed T4P staining and were structurally distinct from those formed by nonpiliated bacteria. These results are the first demonstration that P. aeruginosa assembles a surface organelle, type IV pili, over a broad range of c-di-GMP concentrations. Assembly of pili at low c-di-GMP concentrations requires a polarly localized c-di-GMP binding protein and phosphodiesterase, FimX; this requirement for FimX is bypassed at high c-di-GMP concentrations. Thus, P. aeruginosa can assemble the same surface organelle in distinct ways for motility or adhesion under very different environmental conditions. PMID:22685276

  12. Evaluation of three analytical techniques used to determine high levels of volatile organic compounds in type IV sludge from Rocky Flats Plant

    SciTech Connect

    Parish, K.J.; Applegate, D.V.; Tsai, Y.

    1996-01-01

    Before disposal, radioactive sludge (Type IV) from Rocky Flats Plant (RFP) must be evaluated for volatile organic compound (VOC) content. The Type IV sludge consists of organic solvents, degreasers, cutting oils, and transuranic (TRU) waste mixed with calcium silicate (MicroCel E{reg_sign}) and Oil Dri{reg_sign} to form a grease or paste-like material. For laboratory testing, a simulated Type IV RFP sludge (nonradioactive) was prepared at Argonne National Laboratory-East. This sludge has a composition similar to that expected from field samples. On the basis of historical information, a typical Type IV sludge is expected to contain approximately 1-10 percent of three target VOCs. The objective of this work is to evaluate three proposed methods for the determination of high levels of these three VOCs in Type IV sludge. The three methods are (1) static headspace gas analysis, (2) methanol extraction, and (3) ethylene glycol extraction. All three methods employ gas chromatography/mass spectrometry (GC/MS). They were evaluated regarding general method performance criteria, ease of operation, and amounts of secondary mixed waste generated.

  13. Novel Class of Mutations of pilS Mutants, Encoding Plasmid R64 Type IV Prepilin: Interface of PilS-PilV Interactions▿

    PubMed Central

    Shimoda, Eriko; Muto, Tatsuya; Horiuchi, Takayuki; Furuya, Nobuhisa; Komano, Teruya

    2008-01-01

    The type IV pili of plasmid R64 belonging to the type IVB group are required only for liquid mating. They consist of the major and minor components PilS pilin and PilV adhesin, respectively. PilS pilin is first synthesized as a 22-kDa prepilin from the pilS gene and is then processed to a 19-kDa mature pilin by PilU prepilin peptidase. In a previous genetic analysis, we identified four classes of the pilS mutants (T. Horiuchi and T. Komano, J. Bacteriol. 180:4613-4620, 1998). The products of the class I pilS mutants were not processed by prepilin peptidase; the products of the class II mutants were not secreted; in the class III mutants type IV pili with reduced activities in liquid mating were produced; and in the class IV mutants type IV pili with normal activities were produced. Here, we describe a novel class, class V, of pilS mutants. Mutations in the pilS gene at Gly-56 or Tyr-57 produced type IV pili lacking PilV adhesin, which were inactive in liquid mating. Residues 56 and 57 of PilS pilin are suggested to function as an interface of PilS-PilV interactions. PMID:18065540

  14. Rotational velocities of A-type stars. IV. Evolution of rotational velocities

    NASA Astrophysics Data System (ADS)

    Zorec, J.; Royer, F.

    2012-01-01

    Context. In previous works of this series, we have shown that late B- and early A-type stars have genuine bimodal distributions of rotational velocities and that late A-type stars lack slow rotators. The distributions of the surface angular velocity ratio Ω/Ωcrit (Ωcrit is the critical angular velocity) have peculiar shapes according to spectral type groups, which can be caused by evolutionary properties. Aims: We aim to review the properties of these rotational velocity distributions in some detail as a function of stellar mass and age. Methods: We have gathered vsini for a sample of 2014 B6- to F2-type stars. We have determined the masses and ages for these objects with stellar evolution models. The (Teff,log L/L⊙)-parameters were determined from the uvby-β photometry and the HIPPARCOS parallaxes. Results: The velocity distributions show two regimes that depend on the stellar mass. Stars less massive than 2.5 M⊙ have a unimodal equatorial velocity distribution and show a monotonical acceleration with age on the main sequence (MS). Stars more massive have a bimodal equatorial velocity distribution. Contrarily to theoretical predictions, the equatorial velocities of stars from about 1.7 M⊙ to 3.2 M⊙ undergo a strong acceleration in the first third of the MS evolutionary phase, while in the last third of the MS they evolve roughly as if there were no angular momentum redistribution in the external stellar layers. The studied stars might start in the ZAMS not necessarily as rigid rotators, but with a total angular momentum lower than the critical one of rigid rotators. The stars seem to evolve as differential rotators all the way of their MS life span and the variation of the observed rotational velocities proceeds with characteristic time scales δt ≈ 0.2 tMS, where tMS is the time spent by a star in the MS. Full Table 1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc

  15. Hecke-Clifford Algebras and Spin Hecke Algebras IV: Odd Double Affine Type

    NASA Astrophysics Data System (ADS)

    Khongsap, Ta; Wang, Weiqiang

    2009-01-01

    We introduce an odd double affine Hecke algebra (DaHa) generated by a classical Weyl group W and two skew-polynomial subalgebras of anticommuting generators. This algebra is shown to be Morita equivalent to another new DaHa which are generated by W and two polynomial-Clifford subalgebras. There is yet a third algebra containing a spin Weyl group algebra which is Morita (super)equivalent to the above two algebras. We establish the PBW properties and construct Verma-type representations via Dunkl operators for these algebras.

  16. Spectral types for objects in the Kiso survey. IV - Data for 81 stars

    NASA Technical Reports Server (NTRS)

    Wegner, Gary; Mcmahan, Robert K.

    1988-01-01

    Spectroscopy and spectral types for 81 ultraviolet-excess objects found in the Kiso Schmidt-camera survey are reported. The data were secured with the McGraw-Hill 1.3 m telescope at 8-A resolution covering the wavelength interval 4000 -7200 A using the Mark II spectrograph. Descriptions of the spectra of some of the more peculiar objects found in this sample are given and include 14 sub-dwarfs, 23 definite DA white dwarfs, including a magnetic one, and one DQ whie dwarf, eight quasars and emission-line objects, and a new composite DA + dM system. More spectroscopy of the new cataclysmic variable KUV 01584-0939 and a possibly related object is also described.

  17. Transition of Crack from Type IV to Type II Resulting from Improved Utilization of Boron in the Modified 9Cr-1Mo Steel Weldment

    NASA Astrophysics Data System (ADS)

    Das, C. R.; Albert, S. K.; Swaminathan, J.; Raju, S.; Bhaduri, A. K.; Murty, B. S.

    2012-10-01

    The roles of boron and heat-treatment temperature in improving the type IV cracking resistance of modified 9Cr-1Mo steel weldment were studied. Two different heats of P91 steel, one without boron, designated as P91 and the other with controlled addition of boron with very low nitrogen, designated as P91B, were melted for the current study. The addition of Boron to modified 9Cr-1Mo steel has increased the resistance against softening in fine-grained heat-affected zones (FGHAZ) and intercritical heat-affected zones (ICHAZ) of the weldment. Creep rupture life of boron containing modified 9Cr-1Mo steel weldment, prepared from 1423 K (1150 °C) normalized base metal, was found to be much higher than that prepared from 1323 K (1050 °C) normalized base metal because of the stabilization of lath martensite by fine M23C6 precipitates. This finding is in contrast to the reduction in creep rupture life of P91 weldment prepared from 1423 K (1150 °C) normalized base metal compared with that of the weldment prepared from 1323 K (1050 °C) normalized base metal. The trace of failure path from the weld metal to ICHAZ in P91B weldment was indicative of type II failure in contrast to type IV failure outside the HAZ and base metal junction in P91 weldment, which suggested that boron strengthened the microstructure of the HAZ, whereby the utilization of boron at a higher normalizing temperature seemed to be significantly greater than that at the lower normalizing temperature.

  18. CD44/chondroitin sulfate proteoglycan and alpha 2 beta 1 integrin mediate human melanoma cell migration on type IV collagen and invasion of basement membranes.

    PubMed Central

    Knutson, J R; Iida, J; Fields, G B; McCarthy, J B

    1996-01-01

    Tumor cell invasion of basement membranes (BM) represents one of the critical steps in the metastatic process. Tumor cell recognition of individual BM matrix components may involve individual cell adhesion receptors, such as integrins or cell surface proteoglycans, or may involve a coordinate action of both types of receptors. In this study, we have focused on the identification of a cell surface CD44/chondroitin sulfate proteoglycan (CSPG) and alpha 2 beta 1 integrin on human melanoma cells that are both directly involved in the in vitro invasion of reconstituted BM via a type IV collagen-dependent mechanism. Interfering with cell surface expression of human melanoma CSPG with either p-nitro-phenyl-beta-D-xylopyranoside treatment or anti-CD44 monoclonal antibody (mAb) preincubation (mAb) preincubation inhibits melanoma cell invasion through reconstituted BM. These treatments also strongly inhibit melanoma cell migration on type IV collagen, however, they are ineffective at inhibiting cell adhesion to type IV collagen. Purified melanoma cell surface CD44/CSPG, or purified chondroitin sulfate, bind to type IV collagen affinity columns, consistent with a role for CD44/CSPG-type IV collagen interactions in mediating tumor cell invasion. In contrast, melanoma cell migration on laminin (LM) does not involve CD44/CSPG, nor does CD44/CSPG bind to LM, suggesting that CD44/CSPG-type IV collagen interactions are specific in nature. Additionally, anti-alpha 2 and anti-beta 1 integrin mAbs are capable of blocking melanoma cell invasion of reconstituted BM. Both of these anti-integrin mAbs inhibit melanoma cell adhesion and migration on type IV collagen, whereas only anti-beta 1 mAb inhibits cell adhesion to LM. Collectively, these results indicate that melanoma cell adhesion to type IV collagen is an important consideration in invasion of reconstituted BM in vitro, and suggest that CD44/CSPG and alpha 2 beta 1 integrin may collaborate to promote human melanoma cell adhesion

  19. SVBR-100 module-type fast reactor of the IV generation for regional power industry

    NASA Astrophysics Data System (ADS)

    Zrodnikov, A. V.; Toshinsky, G. I.; Komlev, O. G.; Stepanov, V. S.; Klimov, N. N.

    2011-08-01

    In the report the following is presented: basic conceptual provisions of the innovative nuclear power technology (NPT) based on modular fast reactors (FR) SVBR-100, summarized results of calculations of the reactor, analysis of the opportunities of multi-purpose application of such reactor facilities (RF) including export potentials with due account of nonproliferation requirements. The most important features of the proposed NPT analyzed in the report are as follows: (1) integral (monoblock) arrangement of the primary circuit equipment with entire elimination of the primary circuit pipelines and valves that considerably reduces the construction and assembly works period and coupling with high boiling point of lead-bismuth coolant (LBC) deterministically eliminates accidents of the LOCA type, (2) option for 100 MWe power and dimensions of the reactor provide: on the one hand, an opportunity to transport the reactor monoblock in factory-readiness by railway as well as other kinds of transport, on the other hand, core breeding ratio (CBR) exceeds 1 while MOX-fuel is used. The preferable area of application of RF SVBR-100 is regional and small power requiring power-units of electric power in a range of (100-600) MW, which could be used for cogeneration-based district heating while locating them nearby cities as well as for generation of electric power in a mode of load tracking in the regions with low network systems.

  20. Experimental holographic movie IV: the projection-type display system using a retro-directive screen

    NASA Astrophysics Data System (ADS)

    Higuchi, Kazuhito; Ishii, Ken'ichiro; Ishikawa, Jun; Hiyama, Shigeo

    1995-04-01

    Holographic movies can be seen as a tool to estimate the picture quality of moving holographic images as a step towards holographic television. The authors have previously developed three versions of an experimental holographic movie system, and this paper is a report on an improved version 4 of the system. The new version features a newly-developed projection-type display with a retro-directive beaded-screen, and an automatic film driver unit which moves perforated 35 mm holographic film intermittently with a shutter. A twin diamond-shaped hologram format, which was developed in the earlier version 2, is adopted for the films. The films comprise a series of reconstructed moving holographic images with minimal blurring. The optical arrangement and structure of the version 4 system enable the viewers to watch the film images in an open space, which in turn relieves them of the psychological pressure they felt with the previous three versions, when they had to squint into a narrow window built into a wall on the side of the device.

  1. Amide bond hydrolysis in peptides and cyclic peptides catalyzed by a dimeric Zr(IV)-substituted Keggin type polyoxometalate.

    PubMed

    Ly, Hong Giang T; Absillis, Gregory; Parac-Vogt, Tatjana N

    2013-08-14

    Detailed kinetic studies on the hydrolysis of glycylserine (Gly-Ser) and glycylglycine (Gly-Gly) in the presence of the dimeric zirconium(IV)-substituted Keggin type polyoxometalate (Et2NH2)8[{α-PW11O39Zr(μ-OH)(H2O)}2]·7H2O (1) were performed by a combination of (1)H, (13)C and (31)P NMR spectroscopy. The observed rate constants for the hydrolysis of Gly-Ser and Gly-Gly at pD 5.4 and 60 °C were 63.3 × 10(-7) s(-1) and 4.44 × 10(-7) s(-1) respectively, representing a significant acceleration as compared to the uncatalyzed reactions. The pD dependence of the rate constant for both reactions exhibited a bell-shaped profile with the fastest hydrolysis observed in the pD range of 5.5-6.0. Interaction of 1 with Gly-Ser and Gly-Gly via their amine nitrogen and amide oxygen was proven by (13)C NMR spectroscopy. The effective hydrolysis of Gly-Ser in the presence of 1 is most likely a combination of the polarization of the amide oxygen due to its binding to the Zr(IV) ion in 1 and the intramolecular attack of the Ser hydroxyl group on the amide carbonyl carbon. The effect of temperature, inhibitors, and ionic strength on the hydrolysis rate constant was also examined. The solution structure of 1 was investigated by means of (31)P NMR spectroscopy, revealing that its stability is highly dependent on pH, concentration and temperature. A 2.0 mM solution of 1 was found to be fully stable under hydrolytic conditions (pD 5.4 and 60 °C) both in the presence and in the absence of the dipeptides. PMID:23787813

  2. Genome Sequencing of Xanthomonas vasicola Pathovar vasculorum Reveals Variation in Plasmids and Genes Encoding Lipopolysaccharide Synthesis, Type-IV Pilus and Type-III Secretion Effectors

    PubMed Central

    Wasukira, Arthur; Coulter, Max; Al-Sowayeh, Noorah; Thwaites, Richard; Paszkiewicz, Konrad; Kubiriba, Jerome; Smith, Julian; Grant, Murray; Studholme, David J.

    2014-01-01

    Xanthomonas vasicola pathovar vasculorum (Xvv) is the bacterial agent causing gumming disease in sugarcane. Here, we compare complete genome sequences for five isolates of Xvv originating from sugarcane and one from maize. This identified two distinct types of lipopolysaccharide synthesis gene clusters among Xvv isolates: one is similar to that of Xanthomonas axonopodis pathovar citri (Xac) and is probably the ancestral type, while the other is similar to those of the sugarcane-inhabiting species, Xanthomonas sacchari. Four of six Xvv isolates harboured sequences similar to the Xac plasmid, pXAC47, and showed a distinct Type-IV pilus (T4P) sequence type, whereas the T4P locus of the other two isolates resembled that of the closely related banana pathogen, Xanthomonas campestris pathovar musacearum (Xcm). The Xvv isolate from maize has lost a gene encoding a homologue of the virulence effector, xopAF, which was present in all five of the sugarcane isolates, while xopL contained a premature stop codon in four out of six isolates. These findings shed new light on evolutionary events since the divergence of Xvv and Xcm, as well as further elucidating the relationships between the two closely related pathogens. PMID:25437615

  3. Genome Sequencing of Xanthomonas vasicola Pathovar vasculorum Reveals Variation in Plasmids and Genes Encoding Lipopolysaccharide Synthesis, Type-IV Pilus and Type-III Secretion Effectors.

    PubMed

    Wasukira, Arthur; Coulter, Max; Al-Sowayeh, Noorah; Thwaites, Richard; Paszkiewicz, Konrad; Kubiriba, Jerome; Smith, Julian; Grant, Murray; Studholme, David J

    2014-01-01

    Xanthomonas vasicola pathovar vasculorum (Xvv) is the bacterial agent causing gumming disease in sugarcane. Here, we compare complete genome sequences for five isolates of Xvv originating from sugarcane and one from maize. This identified two distinct types of lipopolysaccharide synthesis gene clusters among Xvv isolates: one is similar to that of Xanthomonas axonopodis pathovar citri (Xac) and is probably the ancestral type, while the other is similar to those of the sugarcane-inhabiting species, Xanthomonas sacchari. Four of six Xvv isolates harboured sequences similar to the Xac plasmid, pXAC47, and showed a distinct Type-IV pilus (T4P) sequence type, whereas the T4P locus of the other two isolates resembled that of the closely related banana pathogen, Xanthomonas campestris pathovar musacearum (Xcm). The Xvv isolate from maize has lost a gene encoding a homologue of the virulence effector, xopAF, which was present in all five of the sugarcane isolates, while xopL contained a premature stop codon in four out of six isolates. These findings shed new light on evolutionary events since the divergence of Xvv and Xcm, as well as further elucidating the relationships between the two closely related pathogens. PMID:25437615

  4. EARLY-TYPE GALAXIES AT z {approx} 1.3. IV. SCALING RELATIONS IN DIFFERENT ENVIRONMENTS

    SciTech Connect

    Raichoor, A.; Mei, S.; Huertas-Company, M.; Stanford, S. A.; Rettura, A.; Jee, M. J.; Holden, B. P.; Illingworth, G.; Rosati, P.; Shankar, F.; Tanaka, M.; Ford, H.; Postman, M.; White, R. L.; Blakeslee, J. P.; Demarco, R.

    2012-02-01

    We present the Kormendy and mass-size relations (MSR) for early-type galaxies (ETGs) as a function of environment at z {approx} 1.3. Our sample includes 76 visually classified ETGs with masses 10{sup 10} < M/M{sub Sun} < 10{sup 11.5}, selected in the Lynx supercluster and in the Great Observatories Origins Deep Survey/Chandra Deep Field South field; 31 ETGs in clusters, 18 in groups, and 27 in the field, all with multi-wavelength photometry and Hubble Space Telescope/Advanced Camera for Surveys observations. The Kormendy relation, in place at z {approx} 1.3, does not depend on the environment. The MSR reveals that ETGs overall appear to be more compact in denser environments: cluster ETGs have sizes on average around 30%-50% smaller than those of the local universe and a distribution with a smaller scatter, whereas field ETGs show an MSR with a similar distribution to the local one. Our results imply that (1) the MSR in the field did not evolve overall from z {approx} 1.3 to present; this is interesting and in contrast to the trend found at higher masses from previous works; (2) in denser environments, either ETGs have increased in size by 30%-50% on average and spread their distributions, or more ETGs have been formed within the dense environment from non-ETG progenitors, or larger galaxies have been accreted to a pristine compact population to reproduce the MSR observed in the local universe. Our results are driven by galaxies with masses M {approx}< 2 Multiplication-Sign 10{sup 11} M{sub Sun} and those with masses M {approx} 10{sup 11} M{sub Sun} follow the same trends as that of the entire sample. Following the Valentinuzzi et al. definition of superdense ETGs, {approx}35%-45% of our cluster sample is made up of superdense ETGs.

  5. PHOTOMETRIC PROPERTIES FOR SELECTED ALGOL-TYPE BINARIES. IV. AV HYDRAE AND DZ CASSIOPEIAE

    SciTech Connect

    Yang, Y.-G.; Dai, H.-F.; Li, L.-H.

    2012-08-15

    We present BVR photometric observations and several eclipsing times for AV Hya and DZ Cas from 2004 to 2011. Using the Wilson-Devinney method, the photometric solutions with hot spots were deduced from their asymmetric light curves. The results indicate that both stars are Algol-type binaries, whose mass ratio, q{sub ph}, and fill-out factor of the primary, f{sub 1}, are q{sub ph} = 0.255({+-} 0.002) and f{sub 1} = 81.2({+-} 0.2)% for AV Hya, and q{sub ph} = 0.093({+-} 0.003) and f{sub 1} = 98.7({+-} 0.3)% for DZ Cas. Based on all available light minimum times, it is discovered that the O - C curve of each star could be described by a light-time orbit overlying on a downward parabola. Their periods and amplitudes are P{sub 3} = 37.2({+-} 0.7) yr and A = 0fd0095({+-}0fd0006) for AV Hya, and P{sub 3} = 62.5({+-} 1.0) yr and A = 0fd0183({+-}0fd0007) for DZ Cas. Cyclic variations may result from the light-time effect due to the third body. The secular period decrease rates are dP/dt = -1.47({+-} 0.04) Multiplication-Sign 10{sup -7} days yr{sup -1} for AV Hya and dP/dt = -0.92({+-} 0.04) Multiplication-Sign 10{sup -7} days yr{sup -1} for DZ Cas. This may be interpreted using mass and angular momentum loss from the system. With decreasing period, the fill-out factor of the primary increases and it may finally fill its inner Roche lobe. Therefore, AV Hya and DZ Cas with a secular period decrease will evolve from semi-detached configurations into contact ones.

  6. Serum anti-collagen type IV IgM antibodies and development of diabetic nephropathy in diabetics with essential hypertension

    PubMed Central

    Tsinlikov, Ivan; Tsinlikova, Ivanka; Nicoloff, George; Blazhev, Alexander; Garev, Antoan

    2016-01-01

    Introduction and aims Arterial hypertension and diabetic vascular complications are connected with an elevated degradation of elastic tissue. This process leads to an increased production of antibodies to collagen type IV (ACIV Abs). In the present investigation we studied whether the serum levels of antibodies (IgG, IgM and IgA) to collagen are related with microvascular complications. Material and methods Serum levels of antibodies to collagen type IV (ACIV) IgG, IgM and IgA were measured using an ELISA method in 93 patients with type 2 diabetes mellitus and arterial hypertension (AH) (mean age 61.4 ±11.3 years, diabetes duration 9.88 ±3.12 years; hypertension duration 9.28 ±4.98). These values were compared to serum antibodies to CIV in 42 age and sex matched controls. Results ACIV IgM antibodies levels in patients with AH and T2DM were statisticaly significantly higher than controls 0.178 (0.145÷0.220) vs. 0.142 (0.118÷0.173) (KW = 6.31; p = 0.01). Group 1 (patients with microvascular complications) showed significantly higher levels of ACIV IgM than controls 0.180 (0.136÷0.223) vs. 0.142 (0.118÷0.173) (KW = 5.03; p = 0.02). Patients from Group 2 showed statistically significantly higher levels of ACIV IgM than controls 0.176 (0.151÷0.202) vs. 0.142 (0.118÷0.173) (KW = 6.15; p = 0.01). ACIV IgM antibodies showed correlation with microalbuminuria (r = 0.21); (p = 0.04), BMI (r = 0.19); (p = 0.04), creatinine clearance (r = –0.36); (p = 0.01) and GFR (r = –0.34); (p = 0.02). Conclusions Our study showed an association between elevation of serum levels of ACIV IgM and development of diabetic nephropathy. We suggest that levels of ACIV IgM can be useful method for identfying a high risk for development of diabetic nephropathy. PMID:27095927

  7. Displacement of the Predominant Dengue Virus from Type 2 to Type 1 with a Subsequent Genotype Shift from IV to I in Surabaya, Indonesia 2008–2010

    PubMed Central

    Yamanaka, Atsushi; Mulyatno, Kris C.; Susilowati, Helen; Hendrianto, Eryk; Ginting, Amor P.; Sary, Dian D.; Rantam, Fedik A.; Soegijanto, Soegeng; Konishi, Eiji

    2011-01-01

    Indonesia has annually experienced approximately 100,000 reported cases of dengue fever (DF) and dengue hemorrhagic fever (DHF) in recent years. However, epidemiological surveys of dengue viruses (DENVs) have been limited in this country. In Surabaya, the second largest city, a single report indicated that dengue virus type 2 (DENV2) was the predominant circulating virus in 2003–2005. We conducted three surveys in Surabaya during: (i) April 2007, (ii) June 2008 to April 2009, and (iii) September 2009 to December 2010. A total of 231 isolates were obtained from dengue patients and examined by PCR typing. We found that the predominant DENV shifted from type 2 to type 1 between October and November 2008. Another survey using wild-caught mosquitoes in April 2009 confirmed that dengue type 1 virus (DENV1) was the predominant type in Surabaya. Phylogenetic analyses of the nucleotide sequences of the complete envelope gene of DENV1 indicated that all 22 selected isolates in the second survey belonged to genotype IV and all 17 selected isolates in the third survey belonged to genotype I, indicating a genotype shift between April and September 2009. Furthermore, in December 2010, isolates were grouped into a new clade of DENV1 genotype I, suggesting clade shift between September and December 2010. According to statistics reported by the Surabaya Health Office, the proportion of DHF cases among the total number of dengue cases increased about three times after the type shift in 2008. In addition, the subsequent genotype shift in 2009 was associated with the increased number of total dengue cases. This indicates the need for continuous surveillance of circulating viruses to predict the risk of DHF and DF. PMID:22087290

  8. The Effect of Dislocation Type (Crowe Types I-IV) on Pelvic Development in Developmental Dysplasia of the Hip: A Radiologic Study of Anatomy.

    PubMed

    Bilgen, Ömer Faruk; Salar, Necmettin; Bilgen, Muhammet Sadık; Mutlu, Müren; Kara, Gökhan Kürşat; Gürsel, Enis

    2015-05-01

    Classification of hip pathology in developmental dysplasia of the hip (DDH) helps in appropriate placement of implants during total hip arthroplasty. We examined preoperative unilateral and bilateral pelvic radiographs of 57 patients (114 hips) undergoing total hip arthroplasty because of DDH. Both sides of the pelvis were visually separated into 3 areas for comparison. When area ratios of hips with Crowe types II, III, and IV DDH were compared with ratios for healthy hips, values in hips with DDH were significantly low for the iliac wings, significantly high for the acetabular regions, and significantly low for the ischial area. Using a line crossing the healthy hip's teardrop and parallel to a line joining the distal sacroiliac joints is useful for calculating limb-length discrepancy. PMID:25499171

  9. Identification and functional analysis of a novel mutation in the SOX10 gene associated with Waardenburg syndrome type IV.

    PubMed

    Wang, Hong-Han; Chen, Hong-Sheng; Li, Hai-Bo; Zhang, Hua; Mei, Ling-Yun; He, Chu-Feng; Wang, Xing-Wei; Men, Mei-Chao; Jiang, Lu; Liao, Xin-Bin; Wu, Hong; Feng, Yong

    2014-03-15

    Waardenburg syndrome type IV (WS4) is a rare genetic disorder, characterized by auditory-pigmentary abnormalities and Hirschsprung disease. Mutations of the EDNRB gene, EDN3 gene, or SOX10 gene are responsible for WS4. In the present study, we reported a case of a Chinese patient with clinical features of WS4. In addition, the three genes mentioned above were sequenced in order to identify whether mutations are responsible for the case. We revealed a novel nonsense mutation, c.1063C>T (p.Q355*), in the last coding exon of SOX10. The same mutation was not found in three unaffected family members or 100 unrelated controls. Then, the function and mechanism of the mutation were investigated in vitro. We found both wild-type (WT) and mutant SOX10 p.Q355* were detected at the expected size and their expression levels are equivalent. The mutant protein also localized in the nucleus and retained the DNA-binding activity as WT counterpart; however, it lost its transactivation capability on the MITF promoter and acted as a dominant-negative repressor impairing function of the WT SOX10. PMID:24440785

  10. Fusion of lysosomes with secretory organelles leads to uncontrolled exocytosis in the lysosomal storage disease mucolipidosis type IV.

    PubMed

    Park, Soonhong; Ahuja, Malini; Kim, Min Seuk; Brailoiu, G Cristina; Jha, Archana; Zeng, Mei; Baydyuk, Maryna; Wu, Ling-Gang; Wassif, Christopher A; Porter, Forbes D; Zerfas, Patricia M; Eckhaus, Michael A; Brailoiu, Eugen; Shin, Dong Min; Muallem, Shmuel

    2016-02-01

    Mutations in TRPML1 cause the lysosomal storage disease mucolipidosis type IV (MLIV). The role of TRPML1 in cell function and how the mutations cause the disease are not well understood. Most studies focus on the role of TRPML1 in constitutive membrane trafficking to and from the lysosomes. However, this cannot explain impaired neuromuscular and secretory cells' functions that mediate regulated exocytosis. Here, we analyzed several forms of regulated exocytosis in a mouse model of MLIV and, opposite to expectations, we found enhanced exocytosis in secretory glands due to enlargement of secretory granules in part due to fusion with lysosomes. Preliminary exploration of synaptic vesicle size, spontaneous mEPSCs, and glutamate secretion in neurons provided further evidence for enhanced exocytosis that was rescued by re-expression of TRPML1 in neurons. These features were not observed in Niemann-Pick type C1. These findings suggest that TRPML1 may guard against pathological fusion of lysosomes with secretory organelles and suggest a new approach toward developing treatment for MLIV. PMID:26682800

  11. A novel relaxase homologue is involved in chromosomal DNA processing for type IV secretion in Neisseria gonorrhoeae.

    PubMed

    Salgado-Pabón, Wilmara; Jain, Samta; Turner, Nicholas; van der Does, Chris; Dillard, Joseph P

    2007-11-01

    The Neisseria gonorrhoeae type IV secretion system secretes chromosomal DNA that acts in natural transformation. To examine the mechanism of DNA processing for secretion, we made mutations in the putative relaxase gene traI and used nucleases to characterize the secreted DNA. The nuclease experiments demonstrated that the secreted DNA is single-stranded and blocked at the 5' end. Mutation of traI identified Tyr93 as required for DNA secretion, while substitution of Tyr201 resulted in intermediate levels of DNA secretion. TraI exhibits features of relaxases, but also has features that are absent in previously characterized relaxases, including an HD phosphohydrolase domain and an N-terminal hydrophobic region. The HD domain residue Asp120 was required for wild-type levels of DNA secretion. Subcellular localization studies demonstrated that the TraI N-terminal region promotes membrane interaction. We propose that Tyr93 initiates DNA processing and Tyr201 is required for termination or acts in DNA binding. Disruption of an inverted-repeat sequence eliminated DNA secretion, suggesting that this sequence may serve as the origin of transfer for chromosomal DNA secretion. The TraI domain architecture, although not previously described, is present in 53 uncharacterized proteins, suggesting that the mechanism of TraI function is a widespread process for DNA donation. PMID:17927698

  12. Processing and maturation of the pilin of the type IV secretion system encoded within the gonococcal genetic island.

    PubMed

    Jain, Samta; Kahnt, Jörg; van der Does, Chris

    2011-12-23

    The type IV secretion system (T4SS) encoded within the gonococcal genetic island (GGI) of Neisseria gonorrhoeae has homology to the T4SS encoded on the F plasmid. The GGI encodes the putative pilin protein TraA and a serine protease TrbI, which is homologous to the TraF protein of the RP4 plasmid involved in circularization of pilin subunits of P-type pili. TraA was processed to a 68-amino acid long circular peptide by leader peptidase and TrbI. Processing occurred after co-translational membrane insertion and was independent of other proteins. Circularization occurred after removal of three C-terminal amino acids. Mutational analysis of TraA revealed limited flexibility at the cleavage and joining sites. Mutagenesis of TrbI showed that the conserved Lys-93 and Asp-155 are essential, whereas mutagenesis of Ser-52, the putative catalytic serine did not influence circularization. Further mutagenesis of other serine residues did not identify a catalytic serine, indicating that TrbI either contains redundant catalytic serine residues or does not function via a serine-lysine dyad mechanism. In vitro studies revealed that circularization occurs via a covalent intermediate between the C terminus of TraA and TrbI. The intermediate is processed to the circular form after cleavage of the N-terminal signal sequence. This is the first demonstration of a covalent intermediate in the circularization mechanism of conjugative pili. PMID:22006923

  13. Interplay between type IV pili activity and exopolysaccharides secretion controls motility patterns in single cells of Myxococcus xanthus

    PubMed Central

    Hu, Wei; Gibiansky, Maxsim L.; Wang, Jing; Wang, Chuandong; Lux, Renate; Li, Yuezhong; Wong, Gerard C. L.; Shi, Wenyuan

    2016-01-01

    Myxococcus xanthus performs coordinated social motility of cell groups through the extension and retraction of type IV pili (TFP) on solid surfaces, which requires both TFP and exopolysaccharides (EPS). By submerging cells in a liquid medium containing 1% methylcellulose, M. xanthus TFP-driven motility was induced in isolated cells and independently of EPS. We measured and analyzed the movements of cells using community tracking algorithms, which combine single-cell resolution with statistics from large sample populations. Cells without significant multi-cellular social interactions have surprisingly complex behaviors: EPS− cells exhibited a pronounced increase in the tendency to stand vertically and moved with qualitatively different characteristics than other cells. A decrease in the EPS secretion of cells correlates with a higher instantaneous velocity, but with lower directional persistence in trajectories. Moreover, EPS− cells do not adhere to the surface as strongly as wild-type and EPS overproducing cells, and display a greater tendency to have large deviations between the direction of movement and the cell axis, with cell velocity showing only minimal dependence on the direction of movement. The emerging picture is that EPS does not simply provide rheological resistance to a single mechanism but rather that the availability of EPS impacts motility pattern. PMID:26821939

  14. Legionella Eukaryotic-Like Type IV Substrates Interfere with Organelle Trafficking

    PubMed Central

    de Felipe, Karim Suwwan; Glover, Robert T.; Charpentier, Xavier; Anderson, O. Roger; Reyes, Moraima; Pericone, Christopher D.; Shuman, Howard A.

    2008-01-01

    Legionella pneumophila, the causative agent of Legionnaires' disease, evades phago-lysosome fusion in mammalian and protozoan hosts to create a suitable niche for intracellular replication. To modulate vesicle trafficking pathways, L. pneumophila translocates effector proteins into eukaryotic cells through a Type IVB macro-molecular transport system called the Icm-Dot system. In this study, we employed a fluorescence-based translocation assay to show that 33 previously identified Legionella eukaryotic-like genes (leg) encode substrates of the Icm-Dot secretion system. To assess which of these proteins may contribute to the disruption of vesicle trafficking, we expressed each gene in yeast and looked for phenotypes related to vacuolar protein sorting. We found that LegC3-GFP and LegC7/YlfA-GFP caused the mis-secretion of CPY-Invertase, a fusion protein normally restricted to the yeast vacuole. We also found that LegC7/YlfA-GFP and its paralog LegC2/YlfB-GFP formed large structures around the yeast vacuole while LegC3-GFP localized to the plasma membrane and a fragmented vacuole. In mammalian cells, LegC2/YlfB-GFP and LegC7/YlfA-GFP were found within large structures that co-localized with anti-KDEL antibodies but excluded the lysosomal marker LAMP-1, similar to what is observed in Legionella-containing vacuoles. LegC3-GFP, in contrast, was observed as smaller structures which had no obvious co-localization with KDEL or LAMP-1. Finally, LegC3-GFP caused the accumulation of many endosome-like structures containing undigested material when expressed in the protozoan host Dictyostelium discoideum. Our results demonstrate that multiple Leg proteins are Icm/Dot-dependent substrates and that LegC3, LegC7/YlfA, and LegC2/YlfB may contribute to the intracellular trafficking of L. pneumophila by interfering with highly conserved pathways that modulate vesicle maturation. PMID:18670632

  15. Lie algebra automorphisms as Lie-point symmetries and the solution space for Bianchi type I, II, IV, V vacuum geometries

    NASA Astrophysics Data System (ADS)

    Terzis, Petros A.; Christodoulakis, T.

    2012-12-01

    Lie-group symmetry analysis for systems of coupled, nonlinear ordinary differential equations is performed in order to obtain the entire solution space to Einstein’s field equations for vacuum Bianchi spacetime geometries. The symmetries used are the automorphisms of the Lie algebra of the corresponding three-dimensional isometry group acting on the hyper-surfaces of simultaneity for each Bianchi type, as well as the scaling and the time reparametrization symmetry. A detailed application of the method is presented for Bianchi type IV. The result is the acquisition of the general solution of type IV in terms of sixth Painlevé transcendent PVI, along with the known pp-wave solution. For Bianchi types I, II, V the known entire solution space is attained and very briefly listed, along with two new type V solutions of Euclidean and neutral signature and a type I pp-wave metric.

  16. Regulation of Type IV Pili Contributes to Surface Behaviors of Historical and Epidemic Strains of Clostridium difficile

    PubMed Central

    Purcell, Erin B.; McKee, Robert W.; Bordeleau, Eric; Burrus, Vincent

    2015-01-01

    ABSTRACT The intestinal pathogen Clostridium difficile is an urgent public health threat that causes antibiotic-associated diarrhea and is a leading cause of fatal nosocomial infections in the United States. C. difficile rates of recurrence and mortality have increased in recent years due to the emergence of so-called “hypervirulent” epidemic strains. A great deal of the basic biology of C. difficile has not been characterized. Recent findings that flagellar motility, toxin synthesis, and type IV pilus (TFP) formation are regulated by cyclic diguanylate (c-di-GMP) reveal the importance of this second messenger for C. difficile gene regulation. However, the function(s) of TFP in C. difficile remains largely unknown. Here, we examine TFP-dependent phenotypes and the role of c-di-GMP in controlling TFP production in the historical 630 and epidemic R20291 strains of C. difficile. We demonstrate that TFP contribute to C. difficile biofilm formation in both strains, but with a more prominent role in R20291. Moreover, we report that R20291 is capable of TFP-dependent surface motility, which has not previously been described in C. difficile. The expression and regulation of the pilA1 pilin gene differs between R20291 and 630, which may underlie the observed differences in TFP-mediated phenotypes. The differences in pilA1 expression are attributable to greater promoter-driven transcription in R20291. In addition, R20291, but not 630, upregulates c-di-GMP levels during surface-associated growth, suggesting that the bacterium senses its substratum. The differential regulation of surface behaviors in historical and epidemic C. difficile strains may contribute to the different infection outcomes presented by these strains. IMPORTANCE How Clostridium difficile establishes and maintains colonization of the host bowel is poorly understood. Surface behaviors of C. difficile are likely relevant during infection, representing possible interactions between the bacterium and the

  17. Pea Broth Enhances the Biocontrol Efficacy of Lysobacter capsici AZ78 by Triggering Cell Motility Associated with Biogenesis of Type IV Pilus.

    PubMed

    Tomada, Selena; Puopolo, Gerardo; Perazzolli, Michele; Musetti, Rita; Loi, Nazia; Pertot, Ilaria

    2016-01-01

    Bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type IV pili. To date, little information on the mechanisms involved in the motility of the Lysobacter species has been available. Recently, L. capsici AZ78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. Pea broth medium improved also the biocontrol activity of L. capsici AZ78 against Plasmopara viticola under greenhouse conditions. Noteworthy, the quantity of pea residues remaining on grapevine leaves fostered cell motility in L. capsici AZ78. Based on these results, this unusual motility related to the composition of the growth medium was investigated in bacterial strains belonging to several Lysobacter species. The six L. capsici strains tested developed dendrite-like colonies when grown on jellified pea broth, while the development of dendrite-like colonies was not recorded in the media commonly used in motility assays. To determine the presence of genes responsible for biogenesis of the flagellum and type IV pili, the genome of L. capsici AZ78 was mined. Genes encoding structural components and regulatory factors of type IV pili were upregulated in L. capsici AZ78 cells grown on the above-mentioned medium, as compared with the other tested media. These results provide new insight into the motility mechanism of L. capsici members and the role of type IV pili and pea compounds on the epiphytic fitness and biocontrol features of L. capsici AZ78. PMID:27507963

  18. Pea Broth Enhances the Biocontrol Efficacy of Lysobacter capsici AZ78 by Triggering Cell Motility Associated with Biogenesis of Type IV Pilus

    PubMed Central

    Tomada, Selena; Puopolo, Gerardo; Perazzolli, Michele; Musetti, Rita; Loi, Nazia; Pertot, Ilaria

    2016-01-01

    Bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type IV pili. To date, little information on the mechanisms involved in the motility of the Lysobacter species has been available. Recently, L. capsici AZ78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. Pea broth medium improved also the biocontrol activity of L. capsici AZ78 against Plasmopara viticola under greenhouse conditions. Noteworthy, the quantity of pea residues remaining on grapevine leaves fostered cell motility in L. capsici AZ78. Based on these results, this unusual motility related to the composition of the growth medium was investigated in bacterial strains belonging to several Lysobacter species. The six L. capsici strains tested developed dendrite-like colonies when grown on jellified pea broth, while the development of dendrite-like colonies was not recorded in the media commonly used in motility assays. To determine the presence of genes responsible for biogenesis of the flagellum and type IV pili, the genome of L. capsici AZ78 was mined. Genes encoding structural components and regulatory factors of type IV pili were upregulated in L. capsici AZ78 cells grown on the above-mentioned medium, as compared with the other tested media. These results provide new insight into the motility mechanism of L. capsici members and the role of type IV pili and pea compounds on the epiphytic fitness and biocontrol features of L. capsici AZ78. PMID:27507963

  19. Homology cloning of rat 72 kDa type IV collagenase: cytokine and second-messenger inducibility in glomerular mesangial cells.

    PubMed Central

    Marti, H P; McNeil, L; Davies, M; Martin, J; Lovett, D H

    1993-01-01

    Glomerular mesangial cells (MC) play a central role in the synthesis and turnover of the glomerular extracellular matrix. Prior studies [Davies, Thomas, Martin and Lovett (1988) Biochem. J. 251, 419-425; Martin, Davies, Thomas and Lovett (1989) Kidney Int. 36, 790-801] have characterized at the protein level a 72 kDa type IV collagenase that is secreted by cultured human and rat MC. While exposure of most cell types to interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha) or phorbol ester has little or even an inhibitory effect on 72 kDa type IV collagenase secretion, these factors significantly increased the synthesis of this enzyme by rat MC. Given this divergent pattern of expression, a homology-based PCR cloning strategy using rat MC cDNA templates was employed to define at the molecular level the structure of the mesangial 72 kDa type IV collagenase. The nucleotide sequence within the open reading frame of the rat mesangial 72 kDa type IV collagenase cDNA diverges from the sequence of the human homologue by approx. 9%. The divergence in the 3' untranslated region was much more extensive. Steady-state levels of the 3.1 kb transcript of the 72 kDa type IV collagenase were low or undetectable in resting MC, but were greatly stimulated following incubation with IL-beta, TNF-alpha or phorbol ester. None of these factors induced synthesis by MC of the closely related 92 kDa type IV collagenase. Synthesis by MC of the 72 kDa type IV collagenase was also induced by second-messenger analogues, including 8-bromo-cyclic AMP and forskolin. It is concluded that MC regulate the expression of this enzyme in an unusual, tissue-specific fashion. Cytokine and second-messenger inducibility may contribute to the enhanced expression of the enzyme during glomerular inflammatory disorders. Images Figure 1 Figure 2 PMID:7916617

  20. P. aeruginosa PilT Structures with and without Nucleotide Reveal a Dynamic Type IV Pilus Retraction Motor

    SciTech Connect

    Misic, Ana M.; Satyshur, Kenneth A.; Forest, Katrina T.

    2010-10-18

    Type IV pili are bacterial extracellular filaments that can be retracted to create force and motility. Retraction is accomplished by the motor protein PilT. Crystal structures of Pseudomonas aeruginosa PilT with and without bound {beta},{gamma}-methyleneadenosine-5{prime}-triphosphate have been solved at 2.6 {angstrom} and 3.1 {angstrom} resolution, respectively, revealing an interlocking hexamer formed by the action of a crystallographic 2-fold symmetry operator on three subunits in the asymmetric unit and held together by extensive ionic interactions. The roles of two invariant carboxylates, Asp Box motif Glu163 and Walker B motif Glu204, have been assigned to Mg{sup 2+} binding and catalysis, respectively. The nucleotide ligands in each of the subunits in the asymmetric unit of the {beta},{gamma}-methyleneadenosine-5{prime}-triphosphate-bound PilT are not equally well ordered. Similarly, the three subunits in the asymmetric unit of both structures exhibit differing relative conformations of the two domains. The 12{sup o} and 20{sup o} domain rotations indicate motions that occur during the ATP-coupled mechanism of the disassembly of pili into membrane-localized pilin monomers. Integrating these observations, we propose a three-state 'Ready, Active, Release' model for the action of PilT.

  1. Bacillus Calmette-Guérin enhances production and secretion of type IV collagenases in peripheral blood mononuclear cells.

    PubMed

    Kageyama, Y; Kawakami, S; Fujii, Y; Kihara, K; Oshima, H

    1997-03-01

    Intravesical administration of bacillus Calmette-Guérin (BCG) is an effective and widely accepted treatment for superficial bladder cancer. Rapid progression of the disease after BCG therapy, however, has been reported in some cases refractory to the treatment. We examined whether BCG treatment and coexistence of peripheral blood mononuclear cells (PBMCs) alter the invasive potential of bladder cancer cells. Production and secretion of two type IV collagenases, matrix metalloproteinase (MMP) 2 and MMP 9, by PBMCs from five healthy donors or bladder cancer cells (T24, JTC 30, and JTC 32) were evaluated by gelatin zymography, western blot analysis, and northern blot analysis. Invasion of bladder cancer cells was also examined using reconstituted basement membrane (Matrigel). BCG (5, 50, and 500 micrograms/ml) had no effect on secretion of MMP 2 and MMP 9 by bladder cancer cells, but increased the production and secretion of MMP 9 by PBMCs in a dose-dependent manner. The coexistence of PBMCs increased invasion of T24 cells and BCG further enhanced the invasion. Thus, BCG promotes invasion of bladder cancer cells under certain conditions. An increase in the secretion of MMP 9 by PBMCs may account in part for the effect. PMID:9140113

  2. Nanoscale Pulling of Type IV Pili Reveals Their Flexibility and Adhesion to Surfaces over Extended Lengths of the Pili

    PubMed Central

    Lu, Shun; Giuliani, Maximiliano; Harvey, Hanjeong; Burrows, Lori L.; Wickham, Robert A.; Dutcher, John R.

    2015-01-01

    Type IV pili (T4P) are very thin protein filaments that extend from and retract into bacterial cells, allowing them to interact with and colonize a broad array of chemically diverse surfaces. The physical aspects that allow T4P to mediate adherence to many different surfaces remain unclear. Atomic force microscopy (AFM) nanoscale pulling experiments were used to measure the mechanical properties of T4P of a mutant strain of Pseudomonas aeruginosa PAO1 unable to retract its T4P. After adhering bacteria to the end of an AFM cantilever and approaching surfaces of mica, gold, or polystyrene, we observed adhesion of the T4P to all of the surfaces. Pulling of single and multiple T4P on retraction of the cantilever from the surfaces could be described using the worm-like chain (WLC) model. Distinct peaks in the measured distributions of the best-fit values of the persistence length Lp on two different surfaces provide strong evidence for close-packed bundling of very flexible T4P. In addition, we observed force plateaus indicating that adhesion of the T4P to both hydrophilic and hydrophobic surfaces occurs along extended lengths of the T4P. These data shed new light, to our knowledge, on T4P flexibility and support a low-affinity, high-avidity adhesion mechanism that mediates bacteria-surface interactions. PMID:26083926

  3. Targeted mutagenesis of intergenic regions in the Neisseria gonorrhoeae gonococcal genetic island reveals multiple regulatory mechanisms controlling type IV secretion.

    PubMed

    Ramsey, Meghan E; Bender, Tobias; Klimowicz, Amy K; Hackett, Kathleen T; Yamamoto, Ami; Jolicoeur, Adrienne; Callaghan, Melanie M; Wassarman, Karen M; van der Does, Chris; Dillard, Joseph P

    2015-09-01

    Gonococci secrete chromosomal DNA into the extracellular environment using a type IV secretion system (T4SS). The secreted DNA acts in natural transformation and initiates biofilm development. Although the DNA and its effects are detectable, structural components of the T4SS are present at very low levels, suggestive of uncharacterized regulatory control. We sought to better characterize the expression and regulation of T4SS genes and found that the four operons containing T4SS genes are transcribed at very different levels. Increasing transcription of two of the operons through targeted promoter mutagenesis did not increase DNA secretion. The stability and steady-state levels of two T4SS structural proteins were affected by a homolog of tail-specific protease. An RNA switch was also identified that regulates translation of a third T4SS operon. The switch mechanism relies on two putative stem-loop structures contained within the 5' untranslated region of the transcript, one of which occludes the ribosome binding site and start codon. Mutational analysis of these stem loops supports a model in which induction of an alternative structure relieves repression. Taken together, these results identify multiple layers of regulation, including transcriptional, translational and post-translational mechanisms controlling T4SS gene expression and DNA secretion. PMID:26076069

  4. Subtilisin-like protease-1 secreted through type IV secretion system contributes to high virulence of Streptococcus suis 2.

    PubMed

    Yin, Supeng; Li, Ming; Rao, Xiancai; Yao, Xinyue; Zhong, Qiu; Wang, Min; Wang, Jing; Peng, Yizhi; Tang, Jiaqi; Hu, Fuquan; Zhao, Yan

    2016-01-01

    Streptococcus suis serotype 2 is an emerging zoonotic pathogen that triggered two outbreaks of streptococcal toxic shock syndrome (STSS) in China. Our previous research demonstrated that a type IV secretion system (T4SS) harbored in the 89K pathogenicity island contributes to the pathogenicity of S. suis 2. In the present study, a shotgun proteomics approach was employed to identify the effectors secreted by T4SS in S. suis 2, and surface-associated subtilisin-like protease-1 (SspA-1) was identified as a potential virulence effector. Western blot analysis and pull-down assay revealed that SspA-1 secretion depends on T4SS. Knockout mutations affecting sspA-1 attenuated S. suis 2 and impaired the pathogen's ability to trigger inflammatory response in mice. And purified SspA-1 induced the secretion of IL-6, TNF-α, and IL-12p70 in THP-1 cells directly. SspA-1 is the first T4SS virulence effector reported in Gram-positive bacteria. Overall, these findings allow us to gain further insights into the pathogenesis of T4SS and STSS. PMID:27270879

  5. Generation mechanism of the slowly drifting narrowband structure in the type IV solar radio bursts observed by AMATERAS

    SciTech Connect

    Katoh, Y.; Nishimura, Y.; Kumamoto, A.; Ono, T.; Iwai, K.; Misawa, H.; Tsuchiya, F.

    2014-05-20

    We investigate the type IV burst event observed by AMATERAS on 2011 June 7, and reveal that the main component of the burst was emitted from the plasmoid eruption identified in the EUV images of the Solar Dynamics Observatory (SDO)/AIA. We show that a slowly drifting narrowband structure (SDNS) appeared in the burst's spectra. Using statistical analysis, we reveal that the SDNS appeared for a duration of tens to hundreds of milliseconds and had a typical bandwidth of 3 MHz. To explain the mechanism generating the SDNS, we propose wave-wave coupling between Langmuir waves and whistler-mode chorus emissions generated in a post-flare loop, which were inferred from the similarities in the plasma environments of a post-flare loop and the equatorial region of Earth's inner magnetosphere. We assume that a chorus element with a rising tone is generated at the top of a post-flare loop. Using the magnetic field and plasma density models, we quantitatively estimate the expected duration of radio emissions generated from coupling between Langmuir waves and chorus emissions during their propagation in the post-flare loop, and we find that the observed duration and bandwidth properties of the SDNS are consistently explained by the proposed generation mechanism. While observations in the terrestrial magnetosphere show that the chorus emissions are a group of large-amplitude wave elements generated naturally and intermittently, the mechanism proposed in the present study can explain both the intermittency and the frequency drift in the observed spectra.

  6. Intercellular adhesion molecule 1 serves as a primary cognate receptor for the Type IV pilus of nontypeable Haemophilus influenzae.

    PubMed

    Novotny, Laura A; Bakaletz, Lauren O

    2016-08-01

    Nontypeable Haemophilus influenzae (NTHI) utilizes the Type IV pilus (Tfp) to adhere to respiratory tract epithelial cells thus colonizing its human host; however, the host cell receptor to which this adhesive protein binds is unknown. From a panel of receptors engaged by Tfp expressed by other bacterial species, we showed that the majority subunit of NTHI Tfp, PilA, bound to intercellular adhesion molecule 1 (ICAM1) and that this interaction was both specific and of high affinity. Further, Tfp-expressing NTHI inoculated on to polarized respiratory tract epithelial cells that expressed ICAM1 were significantly more adherent compared to Tfp-deficient NTHI or NTHI inoculated on to epithelial cells to which ICAM1 gene expression was silenced. Moreover, pre-incubation of epithelial cells with recombinant soluble PilA (rsPilA) blocked adherence of NTHI, an outcome that was abrogated by admixing rsPilA with ICAM1 prior to application on to the target cells. Epithelial cells infected with adenovirus or respiratory syncytial virus showed increased expression of ICAM1; this outcome supported augmented adherence of Tfp-expressing NTHI. Collectively, these data revealed the cognate receptor for NTHI Tfp as ICAM1 and promote continued development of a Tfp-targeted vaccine for NTHI-induced diseases of the airway wherein upper respiratory tract viruses play a key predisposing role. PMID:26857242

  7. Subtilisin-like protease-1 secreted through type IV secretion system contributes to high virulence of Streptococcus suis 2

    PubMed Central

    Yin, Supeng; Li, Ming; Rao, Xiancai; Yao, Xinyue; Zhong, Qiu; Wang, Min; Wang, Jing; Peng, Yizhi; Tang, Jiaqi; Hu, Fuquan; Zhao, Yan

    2016-01-01

    Streptococcus suis serotype 2 is an emerging zoonotic pathogen that triggered two outbreaks of streptococcal toxic shock syndrome (STSS) in China. Our previous research demonstrated that a type IV secretion system (T4SS) harbored in the 89K pathogenicity island contributes to the pathogenicity of S. suis 2. In the present study, a shotgun proteomics approach was employed to identify the effectors secreted by T4SS in S. suis 2, and surface-associated subtilisin-like protease-1 (SspA-1) was identified as a potential virulence effector. Western blot analysis and pull-down assay revealed that SspA-1 secretion depends on T4SS. Knockout mutations affecting sspA-1 attenuated S. suis 2 and impaired the pathogen’s ability to trigger inflammatory response in mice. And purified SspA-1 induced the secretion of IL-6, TNF-α, and IL-12p70 in THP-1 cells directly. SspA-1 is the first T4SS virulence effector reported in Gram-positive bacteria. Overall, these findings allow us to gain further insights into the pathogenesis of T4SS and STSS. PMID:27270879

  8. Constructing bio-layer of heparin and type IV collagen on titanium surface for improving its endothelialization and blood compatibility.

    PubMed

    Zhang, Kun; Chen, Jun-ying; Qin, Wei; Li, Jing-an; Guan, Fang-xia; Huang, Nan

    2016-04-01

    The modification of cardiovascular stent surface for a better micro-environment has gradually changed to multi-molecule, multi-functional designation. In this study, heparin (Hep) and type IV collagen (IVCol) were used as the functional molecule to construct a bifunctional micro-environment of anticoagulation and promoting endothelialization on titanium (Ti). The surface characterization results (AFM, Alcian Blue 8GX Staining and fluorescence staining of IVCol) indicated that the bio-layer of Hep and IVCol were successfully fabricated on the Ti surface through electrostatic self-assembly. The APTT and platelet adhesion test demonstrated that the bionic layer possessed better blood compatibility compared with Ti surface. The adhesion, proliferation, migration and apoptosis tests of endothelial cells proved that the Hep/IVCol layer was able to enhance the endothelialization of the Ti surface. The in vivo animal implantation results manifested that the bionic surface could encourage new endothelialization. This work provides an important reference for the construction of multifunction micro-environment on the cardiovascular scaffold surface. PMID:26936367

  9. EXTRA-ARTICULAR FRACTURE OF THE MEDIAL END OF THE CLAVICLE ASSOCIATED WITH TYPE IV ACROMIOCLAVICULAR DISLOCATION: CAAE REPORT

    PubMed Central

    Correa, Mário Chaves; Gonçalves, Lucas Braga Jacques; Vilela, Jose Carlos Souza; Leonel, Igor Lima; Costa, Lincoln Paiva; de Andrade, Ronaldo Percopi

    2015-01-01

    Fractures of the clavicle and acromioclavicular dislocations are very common injuries when they occur separately. The combination of an acromioclavicular dislocation and a fracture of the lateral third of the clavicle is not rare. However, there are very few reported cases of acromioclavicular dislocations associated with fractures of the middle third of the clavicle; those associated with fractures of the medial third are even rarer. We report the case of an adult male who suffered an acromioclavicular dislocation (type IV) associated with a displaced extra-articular fracture of the medial end of the clavicle (Almann group 3) in a cycling accident. The patient was treated during the acute phase with open reduction and internal fixation of the two lesions. At the clinical evaluation 12 months after the surgery, the patient was asymptomatic, with full active and passive mobility, and normal strength and endurance of the shoulder girdle. Radiographs and a three-dimensional CT scan showed persistent posterosuperior subluxation of the acromioclavicular joint and anatomical consolidation of the clavicular fracture. PMID:27027060

  10. Finite element analysis of type IV cracking in 2.25Cr-1Mo steel weldment based on micro-mechanistic approach

    NASA Astrophysics Data System (ADS)

    Goyal, Sunil; Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Mathew, M. D.

    2011-08-01

    Creep studies were carried out on 2.25Cr-1Mo steel base metal and its fusion-welded weldments at 823 K over the stress range 100-240 MPa. The weldment possessed lower creep rupture strength than the base metal due to type IV failure at the outer edge of the heat-affected zone (HAZ). Premature failure of the weldment was associated with pronounced creep cavitation accompanied with localized creep deformation in the soft intercritical region of the HAZ that was sandwiched between relatively higher creep deformation-resistant microstructural regions. The cavitation was associated with coarse intergranular precipitates in the intercritical region of the HAZ. The type IV cracking in the intercritical region of the HAZ was found to initiate deep inside the weldment and propagate towards the specimen surface. Finite element analysis of stress and strain distributions across the weldment was carried out considering the micro-mechanical strength inhomogeneity across it to explain the observed features of type IV cracking. The estimated higher von-Mises and principal stresses deep inside the intercritical region of the HAZ of the weldment led to the localized creep deformation and preferential cavity nucleation and growth, resulting in type IV failure of the weldment. The role of intergranular precipitate particles in the intercritical region of the HAZ in facilitating creep cavity nucleation by the exhaustion of creep ductility of the material close to the precipitate was corroborated from finite element analysis of stress and strain distribution around the precipitates.

  11. Structural characterization of the mesangial cell type IV collagenase and enhanced expression in a model of immune complex-mediated glomerulonephritis.

    PubMed Central

    Lovett, D. H.; Johnson, R. J.; Marti, H. P.; Martin, J.; Davies, M.; Couser, W. G.

    1992-01-01

    Secretion of glomerular cell-derived matrix metalloproteinases (MMPs) and their specific inhibitors, TIMP-1,2, may play an important role in the turnover of the glomerular extracellular matrix under basal and pathologic conditions. A 66-68 kd MMP secreted by cultured mesangial cells (MC) with activity against Type IV collagen and gelatin was purified and shown by amino-acid sequence analysis to be identical with a Type IV collagenase/gelatinase secreted by certain transformed tumor cell lines. The expression of the mesangial MMP in vivo was limited within the kidney to a small subset of the intrinsic glomerular mesangial cell population. After induction of acute anti-Thy 1.1 glomerulonephritis, there was a large increment in the number of Type IV collagenase-secreting MC, temporally coincident with the development of mesangial hypercellularity. The expression of the MMP inhibitor protein, TIMP-1, was not changed over this period. Ultrastructural studies localized the mesangial MMP to areas of evolving mesangiolysis and at sites of glomerular basement membrane disruption. Enhanced expression of the mesangial cell-derived Type IV collagenase may contribute to the evolution of glomerular injury in this model of immune complex-mediated glomerulonephritis or may be involved in the extensive matrix remodeling process that accompanies this form of glomerular injury. Images Figure 2 Figure 3 Figure 5 Figure 4 Figure 6 Figure 7 Figure 8 and Figure 9 Figure 10 Figure 11 Figure 12 PMID:1321565

  12. Kinetics and sequence specificity of processing of prepilin by PilD, the type IV leader peptidase of Pseudomonas aeruginosa.

    PubMed Central

    Strom, M S; Lory, S

    1992-01-01

    PilD, originally isolated as an essential component for the biogenesis of the type IV pili of Pseudomonas aeruginosa, is a unique endopeptidase responsible for processing the precursors of the P. aeruginosa pilin subunits. It is also required for the cleavage of the leader peptides from the Pdd proteins, which are essential components of an extracellular secretion pathway specific for the export of a number of P. aeruginosa hydrolytic enzymes and toxins. Substrates for PilD are initially synthesized with short, i.e., 6- to 8-amino-acid-long, leader peptides with a net basic charge and share a high degree of amino acid homology through the first 16 to 30 residues at the amino terminus. In addition, they all have a phenylalanine residue at the +1 site relative to the cleavage site, which is N methylated prior to assembly into the oligomeric structures. In this study, the kinetics of leader peptide cleavage from the precursor of the P. aeruginosa pilin subunit by PilD was determined in vitro. The rates of cleavage were compared for purified enzyme and substrate as well as for enzyme and substrate contained within total membranes extracted from P. aeruginosa strains overexpressing the cloned pilD or pilA genes. Optimal conditions were obtained only when both PilD and substrate were contained within total membranes. PilD catalysis of P. aeruginosa prepilin followed normal Michaelis-Menten kinetics, with a measured apparent Km of approximately 650 microM, and a kcat of 180 min-1. The kinetics of PilD processing of another type IV pilin precursor, that from Neisseria gonorrhoeae with a 7-amino-acid-long leader peptide, were essentially the same as that measured for wild-type P. aeruginosa prepilin. Quite different results were obtained for a number of prepilin substrates containing substitutions at the conserved phenylalanine at the +1 position relative to the cleavage site, which were previously shown to be well tolerated in vivo. Substitutions of methionine, serine, and

  13. Milder clinical course of Type IV 3-methylglutaconic aciduria due to a novel mutation in TMEM70.

    PubMed

    Shchelochkov, Oleg A; Li, Fang-Yuan; Wang, Jing; Zhan, Hongli; Towbin, Jeffrey A; Jefferies, John Lynn; Wong, Lee-Jun; Scaglia, Fernando

    2010-01-01

    Mitochondrial disorders are a large and genetically heterogeneous group of disorders posing a significant diagnostic challenge. Only approximately 10-20% of patients have identifiable alterations in their mitochondrial DNA (mtDNA). The remaining ~80-90% of affected patients likely harbor mutations in nuclear genes, most of which are still poorly characterized, and therefore not amenable to efficient screening using currently available molecular methods. Here we present a patient, who has been followed since birth after presenting with neonatal hyperammonemia, lactic acidosis, Reye-like syndrome episodes, and ventricular tachyarrhythmia. Initial biochemical work-up revealed hyperalaninemia, normal plasma glutamine, mild orotic aciduria and significant amounts of urinary 3-methylglutaconic (3-MGC) and 3-methylglutaric (3-MGA) acids. Muscle biopsy demonstrated the presence of ragged-red fibers and non-specific structural abnormalities of mitochondria. The activities of respiratory chain enzymes (complexes I-IV) showed no deficiency. Mutational analysis of the entire mitochondrial genome did not reveal deleterious point mutations or large deletions. Long-term follow-up was significant for a later-onset hypertrophic cardiomyopathy, muscle weakness, and exercise intolerance. Although she had frequent episodes of Reye-like episodes in infancy and early childhood, mostly triggered by illnesses, these symptoms improved significantly with the onset of puberty. In the light of recent reports linking cases of type IV 3-methylglutaconic aciduria (3-MGCA) and hypertrophic cardiomyopathy to mutations in TMEM70, we proceeded with sequencing analysis of this gene. We identified one previously reported splice site mutation, c.317-2A>G and a novel mutation c.494G>A (p.G165D) in an evolutionarily conserved region predicted to be deleterious. This variant was not identified in 100 chromosomes of healthy control subjects and 200 chromosomes of patients with cardiomyopathies. Western

  14. An echistatin C-terminal peptide activates GPIIbIIIa binding to fibrinogen, fibronectin, vitronectin and collagen type I and type IV.

    PubMed Central

    Wright, P S; Saudek, V; Owen, T J; Harbeson, S L; Bitonti, A J

    1993-01-01

    Integrin binding to proteins often involves recognition of domains containing the arginine-glycine-aspartate (RGD) motif. Different binding affinities and specificities of the integrin-ligand protein interactions involve additional protein domains. The n.m.r. structure of the snake-venom protein echistatin suggested that the C-terminal portion of the molecule might be important, in addition to the RGD domain, in binding to the integrin glycoprotein IIbIIIa (GPIIbIIIa) [Saudek, Atkinson and Pelton (1991) Biochem. 30, 7369-7372]. The synthetic C-terminal peptide, echistatin-(40-49), PRNPHKGPAT, (1) inhibited binding of GPIIbIIIa to immobilized echistatin (IC50 3-6 mM), but did not inhibit binding of GPIIbIIIa to immobilized fibrinogen (up to 5 mM peptide), (2) activated GPIIbIIIa binding to fibronectin and vitronectin, usual ligands for the activated integrin, (3) activated binding of GPIIbIIIa to collagen type I and type IV, proteins not usually regarded as ligands for the integrin, and (4) stimulated 125I-fibrinogen binding by human platelets. These findings argue for an interaction of this non-RGD domain in echistatin with GPIIbIIIa, leading to activation of the integrin and extension of the ligand specificity to include immobilized collagen. PMID:7687129

  15. Traversal of a polarized epithelium by pathogenic Neisseriae: facilitation by type IV pili and maintenance of epithelial barrier function.

    PubMed Central

    Merz, A. J.; Rifenbery, D. B.; Arvidson, C. G.; So, M.

    1996-01-01

    BACKGROUND: Gonococci (GC) and meningococci (MC) are gram-negative bacterial pathogens that infect human mucosal epithelia. We would like to understand the functions of specific bacterial components at each stage of mucosal colonization: adhesion, cell invasion, and traversal into subepithelial tissues. As no animal model of mucosal colonization by GC or MC is available, increasingly sophisticated in vitro approaches have been used to address these issues. MATERIALS AND METHODS: We adapted the polarized T84 human epithelial cell system to study GC and MC colonization. Epithelial barrier function was monitored by permeability to soluble tracers and with electrical resistance measurements. Polarized cells were used to assay bacterial traversal of the monolayers, and cells grown on plastic were used to assay adhesion and cell invasion. RESULTS: All pathogenic Neisseriae examined traversed the monolayers. The traversal times were species specific and identical to times established previously in organ culture studies. In contrast to experiments with some enteric pathogens, transmigration by GC and MC was not accompanied by disruption of the epithelial barrier. GC mutants lacking type IV pili were compromised in adhesion, invasion, and traversal of T84 cells. CONCLUSIONS: Experiments with polarized T84 cells mimic key features of organ culture infections and reveal additional aspects of neisserial infection. Epithelial barrier function can be retained during bacterial traversal. Experiments with a nonpiliated GC mutant and its wild-type parent indicated an unexpected role for pili in cell invasion. Our results are consistent with the hypothesis that bacterial adhesion, invasion, or both are rate-limiting for traversal across the epithelium. Images FIG. 1 FIG. 3 PMID:8972489

  16. L-arginine mediated renaturation enhances yield of human, α6 type IV collagen non-collagenous domain from bacterial inclusion bodies

    PubMed Central

    Gunda, Venugopal; Boosani, Chandra Shekhar; Verma, Raj Kumar; Guda, Chittibabu; Akul Sudhakar, Yakkanti

    2012-01-01

    The anti-angiogenic, carboxy terminal non-collagenous domain (NC1) derived from human Collagen type IV alpha 6 chain, [α6(IV)NC1] or hexastatin, was earlier obtained using different recombinant methods of expression in bacterial systems. However, the effect of L-arginine mediated renaturation in enhancing the relative yields of this protein from bacterial inclusion bodies has not been evaluated. In the present study, direct stirring and on-column renaturation methods using L-arginine and different size exclusion chromatography matrices were applied for enhancing the solubility in purifying the recombinant α6(IV)NC1 from bacterial inclusion bodies. This methodology enabled purification of higher quantities of soluble protein from inclusion bodies, which inhibited endothelial cell proliferation, migration and tube formation. Thus, the scope for L-arginine mediated renaturation in obtaining higher yields of soluble, biologically active NC1 domain from bacterial inclusion bodies was evaluated. PMID:22512648

  17. [Targeting of type IV carbonic anhydrases in Capan-1 human pancreatic duct cells is concomitant of the polarization].

    PubMed

    Mairal, A; Fanjul, M; Hollande, E

    1996-01-01

    Carbonic anhydrases II and IV play an essential role in the synthesis and secretion of HCO3- ions in pancreatic duct cells. Secretion of these ions is regulated by the CFTR (cystic fibrosis transmembrane conductance regulator) chloride channel. In the present study, the expression of carbonic anhydrases IV and their targeting to plasma membranes were examined during the growth of human pancreatic duct cells in vitro. Human cancerous pancreatic duct cells of Capan-1 cell line which polarize during their growth were used. We show that: a) these cells express carbonic anhydrases IV continuously during growth in culture, and the expression depends on the stage of growth and the conformation of the cells; b) carbonic anhydrases IV are seen in the cytoplasm in non-polarized cells, but become progressively anchored to plasma membranes as the cells polarize, being targeted to the apical membranes of polarized cells; c) the subcellular distribution of carbonic anhydrases IV indicates that these enzymes are synthetized in rough endoplasmic reticulum and then transported towards the plasma membrane using the classical secretory pathway through the Golgi apparatus. The results indicated that targeting of carbonic anhydrases IV in Capan-1 cells is linked to cellular polarization. PMID:8881572

  18. Increase in SCCmec type IV strains affects trends in antibiograms of meticillin-resistant Staphylococcus aureus at a tertiary-care hospital.

    PubMed

    Ito, Ayumu; Nakaminami, Hidemasa; Fujii, Takeshi; Utsumi, Kenta; Noguchi, Norihisa

    2015-07-01

    The prevalence of community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) strains has become a serious problem worldwide. The aim of this study was to investigate the annual transitions of MRSA strains with the CA-MRSA feature, which were identified as SCCmec type IV or V, in a hospital setting in Japan. Between 2005 and 2012, MRSA strains were collected from a tertiary-care hospital in Tokyo, Japan, and SCCmec typing, detection of the virulence factors and antimicrobial susceptibility testing were conducted. The rate of detection of type II SCCmec, which is found mainly in healthcare-associated MRSA, significantly decreased from 90.0 (2005-2006) to 74.3 % (2011-2012) (P < 0.01). In contrast, the rate of detection of type IV SCCmec, which is mainly found in CA-MRSA, significantly increased from 5.8 (2005-2006) to 16.3 % (2011-2012) (P < 0.01). The rate of detection of the toxic shock syndrome toxin-1 gene significantly decreased from 66.7 (2005-2006) to 51.6 % (2011-2012) (P < 0.01), whilst that of the Panton-Valentine leukocidin gene significantly increased from 0.1 (2005-2006) to 2.1 % (2011-2012) (P < 0.01). The resistance rates of cefotaxime, levofloxacin, clarithromycin and minocycline decreased every year. The resistance rates of these antimicrobial agents for the SCCmec type IV or V strains were significantly lower than those for the SCCmec type I or II strains (P < 0.01, respectively). Therefore, these results suggest that the annual transitions of the virulence factors and antibiograms in MRSA are closely related to the increase of SCCmec type IV/V strains. PMID:25934550

  19. Functional mapping of PilF and PilQ in the Pseudomonas aeruginosa type IV pilus system.

    PubMed

    Koo, Jason; Tang, Tim; Harvey, Hanjeong; Tammam, Stephanie; Sampaleanu, Liliana; Burrows, Lori L; Howell, P Lynne

    2013-04-30

    Pseudomonas aeruginosa uses type IV pili (T4P) to interact with the environment and as key virulence factors when acting as an opportunistic pathogen. Assembly of the outer membrane PilQ secretin channel through which the pili are extruded is essential for pilus biogenesis. The P. aeruginosa T4P pilotin, PilF, is required for PilQ outer membrane localization and assembly into secretins and contains six tetratricopeptide (TPR) protein-protein interaction motifs, suggesting that the two proteins interact. In this study, we found that the first four TPR motifs of PilF are sufficient for PilQ outer membrane targeting, oligomerization, and function. Guided by our structure of PilF, site-directed mutagenesis of the protein surface revealed that a hydrophobic groove on the first TPR is required for PilF-mediated PilQ assembly. Deletion of individual domains within PilQ suggests that the N0, KH-like, or secretin domain, but not the C-terminus, interacts with PilF. Purified PilQ was found to pull down PilF from Pseudomonas cell lysates. Together, these data allow us to propose a model for PilF function in the T4P system. PilF interacts directly or indirectly with the PilQ monomer after translocation of both proteins through the inner membrane and acts as a co-chaperone with the Lol system to facilitate transit across the periplasm to the outer membrane. The mechanism of PilQ insertion and assembly, which appears to be independent of the Bam system, remains to be determined. PMID:23547883

  20. Camel milk attenuates the biochemical and morphological features of diabetic nephropathy: inhibition of Smad1 and collagen type IV synthesis.

    PubMed

    Korish, Aida A; Abdel Gader, Abdel Galil; Korashy, Hesham M; Al-Drees, Abdul Majeed; Alhaider, Abdulqader A; Arafah, Maha M

    2015-03-01

    Diabetic nephropathy (DN) is a common microvascular complication of diabetes mellitus (DM) that worsens its morbidity and mortality. There is evidence that camel milk (CM) improves the glycemic control in DM but its effect on the renal complications especially the DN remains unclear. Thus the current study aimed to characterize the effects of CM treatment on streptozotocin (STZ)-induced DN. Using STZ-induced diabetes, we investigated the effect of CM treatment on kidney function, proteinuria, renal Smad1, collagen type IV (Col4), blood glucose, insulin resistance (IR), lipid peroxidation, the antioxidant superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH). In addition renal morphology was also examined. The current results showed that rats with untreated diabetes exhibited marked hyperglycemia, IR, high serum urea and creatinine levels, excessive proteinuria, increased renal Smad1 and Col4, glomerular expansion, and extracellular matrix deposition. There was also increased lipid peroxidation products, decreased antioxidant enzyme activity and GSH levels. Camel milk treatment decreased blood glucose, IR, and lipid peroxidation. Superoxide dismutase and CAT expression, CAT activity, and GSH levels were increased. The renoprotective effects of CM were demonstrated by the decreased serum urea and creatinine, proteinuria, Smad1, Col4, and preserved normal tubulo-glomerular morphology. In conclusion, beside its hypoglycemic action, CM attenuates the early changes of DN, decreased renal Smad1 and Col4. This could be attributed to a primary action on the glomerular mesangial cells, or secondarily to the hypoglycemic and antioxidant effects of CM. The protective effects of CM against DN support its use as an adjuvant anti-diabetes therapy. PMID:25617480

  1. DNA Substrate-Induced Activation of the Agrobacterium VirB/VirD4 Type IV Secretion System

    PubMed Central

    Cascales, Eric; Atmakuri, Krishnamohan; Sarkar, Mayukh K.

    2013-01-01

    The bitopic membrane protein VirB10 of the Agrobacterium VirB/VirD4 type IV secretion system (T4SS) undergoes a structural transition in response to sensing of ATP binding or hydrolysis by the channel ATPases VirD4 and VirB11. This transition, detectable as a change in protease susceptibility, is required for DNA substrate passage through the translocation channel. Here, we present evidence that DNA substrate engagement with VirD4 and VirB11 also is required for activation of VirB10. Several DNA substrates (oncogenic T-DNA and plasmids RSF1010 and pCloDF13) induced the VirB10 conformational change, each by mechanisms requiring relaxase processing at cognate oriT sequences. VirD2 relaxase deleted of its translocation signal or any of the characterized relaxases produced in the absence of cognate DNA substrates did not induce the structural transition. Translocated effector proteins, e.g., VirE2, VirE3, and VirF, also did not induce the transition. By mutational analyses, we supplied evidence that the N-terminal periplasmic loop of VirD4, in addition to its catalytic site, is essential for early-stage DNA substrate transfer and the VirB10 conformational change. Further studies of VirB11 mutants established that three T4SS-mediated processes, DNA transfer, protein transfer, and pilus production, can be uncoupled and that the latter two processes proceed independently of the VirB10 conformational change. Our findings support a general model whereby DNA ligand binding with VirD4 and VirB11 stimulates ATP binding/hydrolysis, which in turn activates VirB10 through a structural transition. This transition confers an open-channel configuration enabling passage of the DNA substrate to the cell surface. PMID:23564169

  2. Type IV Pilus Assembly Proficiency and Dynamics Influence Pilin Subunit Phospho-Form Macro- and Microheterogeneity in Neisseria gonorrhoeae

    PubMed Central

    Vik, Åshild; Haug Anonsen, Jan; Aas, Finn Erik; Hegge, Finn Terje; Roos, Norbert; Koomey, Michael; Aspholm, Marina

    2014-01-01

    The PilE pilin subunit protein of the gonococcal Type IV pilus (Tfp) colonization factor undergoes multisite, covalent modification with the zwitterionic phospho-form modification phosphoethanolamine (PE). In a mutant lacking the pilin-like PilV protein however, PilE is modified with a mixture of PE and phosphocholine (PC). Moreover, intrastrain variation of PilE PC modification levels have been observed in backgrounds that constitutively express PptA (the protein phospho-form transferase A) required for both PE and PC modification. The molecular basis underlying phospho-form microheterogeneity in these instances remains poorly defined. Here, we examined the effects of mutations at numerous loci that disrupt or perturb Tfp assembly and observed that these mutants phenocopy the pilV mutant vis a vis phospho-form modification status. Thus, PC modification appears to be directly or indirectly responsive to the efficacy of pilin subunit interactions. Despite the complexity of contributing factors identified here, the data favor a model in which increased retention in the inner membrane may act as a key signal in altering phospho-form modification. These results also provide an alternative explanation for the variation in PilE PC levels observed previously and that has been assumed to be due to phase variation of pptA. Moreover, mass spectrometry revealed evidence for mono- and di-methylated forms of PE attached to PilE in mutants deficient in pilus assembly, directly implicating a methyltransferase-based pathway for PC synthesis in N. gonorrhoeae. PMID:24797914

  3. MasABK Proteins Interact with Proteins of the Type IV Pilin System to Affect Social Motility of Myxococcus xanthus

    PubMed Central

    Fremgen, Sarah; Williams, Amanda; Furusawa, Gou; Dziewanowska, Katarzyna; Settles, Matthew; Hartzell, Patricia

    2013-01-01

    Gliding motility is critical for normal development of spore-filled fruiting bodies in the soil bacterium Myxococcus xanthus. Mutations in mgl block motility and development but one mgl allele can be suppressed by a mutation in masK, the last gene in an operon adjacent to the mgl operon. Deletion of the entire 5.5 kb masABK operon crippled gliding and fruiting body development and decreased sporulation. Expression of pilAGHI, which encodes type IV pili (TFP) components essential for social (S) gliding, several cryptic pil genes, and a LuxR family protein were reduced significantly in the Δmas mutant while expression of the myxalamide operon was increased significantly. Localization and two-hybrid analysis suggest that the three Mas proteins form a membrane complex. MasA-PhoA fusions confirmed that MasA is an integral cytoplasmic membrane protein with a ≈100 amino acid periplasmic domain. Results from yeast two-hybrid assays showed that MasA interacts with the lipoprotein MasB and MasK, a protein kinase and that MasB and MasK interact with one another. Additionally, yeast two-hybrid analysis revealed a physical interaction between two gene products of the mas operon, MasA and MasB, and PilA. Deletion of mas may be accompanied by compensatory mutations since complementation of the Δmas social gliding and developmental defects required addition of both pilA and masABK. PMID:23342171

  4. Pseudomonas aeruginosa Type IV Pilus Expression in Neisseria gonorrhoeae: Effects of Pilin Subunit Composition on Function and Organelle Dynamics▿ †

    PubMed Central

    Winther-Larsen, Hanne C.; Wolfgang, Matthew C.; van Putten, Jos P. M.; Roos, Norbert; Aas, Finn Erik; Egge-Jacobsen, Wolfgang M.; Maier, Berenike; Koomey, Michael

    2007-01-01

    Type IV pili (TFP) play central roles in the expression of many phenotypes including motility, multicellular behavior, sensitivity to bacteriophages, natural genetic transformation, and adherence. In Neisseria gonorrhoeae, these properties require ancillary proteins that act in conjunction with TFP expression and influence organelle dynamics. Here, the intrinsic contributions of the pilin protein itself to TFP dynamics and associated phenotypes were examined by expressing the Pseudomonas aeruginosa PilAPAK pilin subunit in N. gonorrhoeae. We show here that, although PilAPAK pilin can be readily assembled into TFP in this background, steady-state levels of purifiable fibers are dramatically reduced relative those of endogenous pili. This defect is due to aberrant TFP dynamics as it is suppressed in the absence of the PilT pilus retraction ATPase. Functionally, PilAPAK pilin complements gonococcal adherence for human epithelial cells but only in a pilT background, and this property remains dependent on the coexpression of both the PilC adhesin and the PilV pilin-like protein. Since P. aeruginosa pilin only moderately supports neisserial sequence-specific transformation despite its assembly proficiency, these results together suggest that PilAPAK pilin functions suboptimally in this environment. This appears to be due to diminished compatibility with resident proteins essential for TFP function and dynamics. Despite this, PilAPAK pili support retractile force generation in this background equivalent to that reported for endogenous pili. Furthermore, PilAPAK pili are both necessary and sufficient for bacteriophage PO4 binding, although the strain remains phage resistant. Together, these findings have significant implications for TFP biology in both N. gonorrhoeae and P. aeruginosa. PMID:17573479

  5. A bipartite signal mediates the transfer of type IV secretion substrates of Bartonella henselae into human cells

    PubMed Central

    Schulein, Ralf; Guye, Patrick; Rhomberg, Thomas A.; Schmid, Michael C.; Schröder, Gunnar; Vergunst, Annette C.; Carena, Ilaria; Dehio, Christoph

    2005-01-01

    Bacterial type IV secretion (T4S) systems mediate the transfer of macromolecular substrates into various target cells, e.g., the conjugative transfer of DNA into bacteria or the transfer of virulence proteins into eukaryotic host cells. The T4S apparatus VirB of the vascular tumor-inducing pathogen Bartonella henselae causes subversion of human endothelial cell (HEC) function. Here we report the identification of multiple protein substrates of VirB, which, upon translocation into HEC, mediate all known VirB-dependent cellular changes. These Bartonella-translocated effector proteins (Beps) A-G are encoded together with the VirB system and the T4S coupling protein VirD4 on a Bartonella-specific pathogenicity island. The Beps display a modular architecture, suggesting an evolution by extensive domain duplication and reshuffling. The C terminus of each Bep harbors at least one copy of the Bep-intracellular delivery domain and a short positively charged tail sequence. This biparte C terminus constitutes a transfer signal that is sufficient to mediate VirB/VirD4-dependent intracellular delivery of reporter protein fusions. The Bep-intracellular delivery domain is also present in conjugative relaxases of bacterial conjugation systems. We exemplarily show that the C terminus of such a conjugative relaxase mediates protein transfer through the Bartonella henselae VirB/VirD4 system into HEC. Conjugative relaxases may thus represent the evolutionary origin of the here defined T4S signal for protein transfer into human cells. PMID:15642951

  6. Nicotinic acetylcholine receptors regulate type 1 inositol 1,4,5-trisphosphate receptor expression via calmodulin kinase IV activation.

    PubMed

    Mizuno, Koji; Kurokawa, Kazuhiro; Ohkuma, Seitaro

    2015-04-01

    Type 1 inositol 1,4,5-trisphosphate receptors (IP3 R-1) are among the important calcium channels regulating intracellular Ca(2+) concentration in the central nervous system. In a previous study, we showed that drugs of abuse, such as cocaine, methamphetamine, and ethanol, induced IP3 R-1 upregulation via the calcium signal transduction pathway in psychological dependence. Although nicotine, a major component in tobacco smoke, participates in psychological and/or physical dependence, it has not yet been clarified how nicotine alters IP3 R-1 expression. The present study, therefore, seeks to clarify the mechanism bgy which nicotine modifies IP3 R-1 expression by using mouse cerebral cortical neurons in primary culture. Nicotine induced dose- and time-dependent upregulation of IP3 R-1 protein following its mRNA increase, and the latter was significantly suppressed by a nonselective nicotinic acetylcholine receptors (nAChR) antagonist, mecamylamine. Both cFos and phosphorylated-cJun (p-cJun) were immediately increased in the nucleus, together with an increase of calmodulin kinase (CaMK) IV but not CaMKII expression after nicotine exposure. A nonselective inhibitor of CaMKs, KN-93, and a calcium chelating regent, BAPTA-AM, completely suppressed the expression of cFos and p-cJun in the nucleus as well as the nicotine-induced IP3 R-1 upregulation. These results indicate that nAChR activation by nicotine upregulates IP3 R-1 via increase of activator protein-1, which is a cFos and cJun dimmer, in the nucleus, with activation of Ca(2+) signaling transduction processes. PMID:25430056

  7. Spectroscopic Studies of Abiotic and Biological Nanomaterials: Silver Nanoparticles, Rhodamine 6G Adsorbed on Graphene, and c-Type Cytochromes and Type IV Pili in Geobacter sulfurreducens

    NASA Astrophysics Data System (ADS)

    Thrall, Elizabeth S.

    This thesis describes spectroscopic studies of three different systems: silver nanoparticles, the dye molecule rhodamine 6G adsorbed on graphene, and the type IV pili and c-type cytochromes produced by the dissimilatory metal-reducing bacterium Geobacter sulfurreducens. Although these systems are quite different in some ways, they can all be considered examples of nanomaterials. A nanomaterial is generally defined as having at least one dimension below 100 nm in size. Silver nanoparticles, with sub-100 nm size in all dimensions, are examples of zero-dimensional nanomaterials. Graphene, a single atomic layer of carbon atoms, is the paradigmatic two-dimensional nanomaterial. And although bacterial cells are on the order of 1 μm in size, the type IV pili and multiheme c-type cytochromes produced by G. sulfurreducens can be considered to be one- and zero-dimensional nanomaterials respectively. A further connection between these systems is their strong interaction with visible light, allowing us to study them using similar spectroscopic tools. The first chapter of this thesis describes research on the plasmon-mediated photochemistry of silver nanoparticles. Silver nanoparticles support coherent electron oscillations, known as localized surface plasmons, at resonance frequencies that depend on the particle size and shape and the local dielectric environment. Nanoparticle absorption and scattering cross-sections are maximized at surface plasmon resonance frequencies, and the electromagnetic field is amplified near the particle surface. Plasmonic effects can enhance the photochemistry of silver particles alone or in conjunction with semiconductors according to several mechanisms. We study the photooxidation of citrate by silver nanoparticles in a photoelectrochemical cell, focusing on the wavelength-dependence of the reaction rate and the role of the semiconductor substrate. We find that the citrate

  8. Bioactive compounds from culinary herbs inhibit a molecular target for type 2 diabetes management, dipeptidyl peptidase IV.

    PubMed

    Bower, Allyson M; Real Hernandez, Luis M; Berhow, Mark A; de Mejia, Elvira Gonzalez

    2014-07-01

    Greek oregano (Origanum vulgare), marjoram (Origanum majorana), rosemary (Rosmarinus officinalis), and Mexican oregano (Lippia graveolens) are concentrated sources of bioactive compounds. The aims were to characterize and examine extracts from greenhouse-grown or commercially purchased herbs for their ability to inhibit dipeptidyl peptidase IV (DPP-IV) and protein tyrosine phosphatase 1B (PTP1B), enzymes that play a role in insulin secretion and insulin signaling, respectively. Greenhouse herbs contained more polyphenols (302.7-430.1 μg of gallic acid equivalents/mg of dry weight of extract (DWE)) and flavonoids (370.1-661.4 μg of rutin equivalents/mg of DWE) compared to the equivalent commercial herbs. Greenhouse rosemary, Mexican oregano, and marjoram extracts were the best inhibitors of DPP-IV (IC₅₀=16, 29, and 59 μM, respectively). Commercial rosemary, Mexican oregano, and marjoram were the best inhibitors of PTP1B (32.4-40.9% at 500 μM). The phytochemicals eriodictyol, naringenin, hispidulin, cirsimaritin, and carnosol were identified by LC-ESI-MS as being present in greenhouse-grown Mexican oregano and rosemary. Computational modeling indicated that hispidulin, carnosol, and eriodictyol would have the best binding affinities for DPP-IV. Biochemically, the best inhibitors of DPP-IV were cirsimaritin (IC₅₀=0.43±0.07 μM), hispidulin (IC₅₀=0.49±0.06 μM), and naringenin (IC₅₀=2.5±0.29 μM). Overall, herbs contain several flavonoids that inhibit DPP-IV and should be investigated further regarding their potential in diabetes management. PMID:24881464

  9. Intervalence charge transfer luminescence: Interplay between anomalous and 5d − 4f emissions in Yb-doped fluorite-type crystals

    SciTech Connect

    Barandiarán, Zoila Seijo, Luis

    2014-12-21

    In this paper, we report the existence of intervalence charge transfer (IVCT) luminescence in Yb-doped fluorite-type crystals associated with Yb{sup 2+}–Yb{sup 3+} mixed valence pairs. By means of embedded cluster, wave function theory ab initio calculations, we show that the widely studied, very broad band, anomalous emission of Yb{sup 2+}-doped CaF{sub 2} and SrF{sub 2}, usually associated with impurity-trapped excitons, is, rather, an IVCT luminescence associated with Yb{sup 2+}–Yb{sup 3+} mixed valence pairs. The IVCT luminescence is very efficiently excited by a two-photon upconversion mechanism where each photon provokes the same strong 4f{sup 14}–1A{sub 1g}→ 4f{sup 13}({sup 2}F{sub 7/2})5de{sub g}–1T{sub 1u} absorption in the Yb{sup 2+} part of the pair: the first one, from the pair ground state; the second one, from an excited state of the pair whose Yb{sup 3+} moiety is in the higher 4f{sup 13}({sup 2}F{sub 5/2}) multiplet. The Yb{sup 2+}–Yb{sup 3+} → Yb{sup 3+}–Yb{sup 2+} IVCT emission consists of an Yb{sup 2+} 5de{sub g} → Yb{sup 3+} 4f{sub 7/2} charge transfer accompanied by a 4f{sub 7/2} → 4f{sub 5/2} deexcitation within the Yb{sup 2+} 4f{sup 13} subshell: [{sup 2}F{sub 5/2}5de{sub g},{sup 2}F{sub 7/2}] → [{sup 2}F{sub 7/2},4f{sup 14}]. The IVCT vertical transition leaves the oxidized and reduced moieties of the pair after electron transfer very far from their equilibrium structures; this explains the unexpectedly large band width of the emission band and its low peak energy, because the large reorganization energies are subtracted from the normal emission. The IVCT energy diagrams resulting from the quantum mechanical calculations explain the different luminescent properties of Yb-doped CaF{sub 2}, SrF{sub 2}, BaF{sub 2}, and SrCl{sub 2}: the presence of IVCT luminescence in Yb-doped CaF{sub 2} and SrF{sub 2}; its coexistence with regular 5d-4f emission in SrF{sub 2}; its absence in BaF{sub 2} and SrCl{sub 2}; the quenching of

  10. Wanted: A Positive Control for Anomalous Subdiffusion

    PubMed Central

    Saxton, Michael J.

    2012-01-01

    Anomalous subdiffusion in cells and model systems is an active area of research. The main questions are whether diffusion is anomalous or normal, and if it is anomalous, its mechanism. The subject is controversial, especially the hypothesis that crowding causes anomalous subdiffusion. Anomalous subdiffusion measurements would be strengthened by an experimental standard, particularly one able to cross-calibrate the different types of measurements. Criteria for a calibration standard are proposed. First, diffusion must be anomalous over the length and timescales of the different measurements. The length-scale is fundamental; the time scale can be adjusted through the viscosity of the medium. Second, the standard must be theoretically well understood, with a known anomalous subdiffusion exponent, ideally readily tunable. Third, the standard must be simple, reproducible, and independently characterizable (by, for example, electron microscopy for nanostructures). Candidate experimental standards are evaluated, including obstructed lipid bilayers; aqueous systems obstructed by nanopillars; a continuum percolation system in which a prescribed fraction of randomly chosen obstacles in a regular array is ablated; single-file diffusion in pores; transient anomalous subdiffusion due to binding of particles in arrays such as transcription factors in randomized DNA arrays; and computer-generated physical trajectories. PMID:23260043

  11. Resolution of Large Azygos Vein Aneurysm Following Stent-Graft Shunt Placement in a Patient with Ehlers-Danlos Syndrome Type IV

    SciTech Connect

    D'Souza, Estelle S.; Williams, David M.; Deeb, G.M.; Cwikiel, Wojciech

    2006-10-15

    Ehlers-Danlos syndrome (EDS) type IV is a rare connective tissue disorder associated with thin-walled, friable arteries and veins predisposing patients to aneurysm formation, dissection, fistula formation, and vessel rupture. Azygos vein aneurysm is an extremely rare condition which has not been reported in association with EDS in the literature. We present a patient with EDS type IV and interrupted inferior vena cava (IVC) with azygos continuation who developed an azygos vein aneurysm. In order to decrease flow through the azygos vein and reduce the risk of aneurysm rupture, a stent-graft shunt was created from the right hepatic vein to the azygos vein via a transhepatic, retroperitoneal route. At 6 month follow-up the shunt was open and the azygos vein aneurysm had resolved.

  12. Characterization of Transcription Factors That Regulate the Type IV Secretion System and Riboflavin Biosynthesis in Wolbachia of Brugia malayi

    PubMed Central

    Li, Zhiru; Carlow, Clotilde K. S.

    2012-01-01

    The human filarial parasite Brugia malayi harbors an endosymbiotic bacterium Wolbachia (wBm) that is required for parasite survival. Consequently, targeting wBm is a promising approach for anti-filarial drug development. The Type IV secretion system (T4SS) plays an important role in bacteria-host interactions and is under stringent regulation by transcription factors. In wBm, most T4SS genes are contained in two operons. We show the wBm is active since the essential assembly factor virB8-1, is transcribed in adult worms and larval stages, and VirB8-1 is present in parasite lysates. We also identify two transcription factors (wBmxR1 and wBmxR2) that bind to the promoter region of several genes of the T4SS. Gel shift assays show binding of wBmxR1 to regions upstream of the virB9-2 and wBmxR2 genes, whereas wBmxR2 binds to virB4-2 and wBmxR1 promoter regions. Interestingly, both transcription factors bind to the promoter of the ribA gene that precedes virB8-1, the first gene in operon 1 of the wBm T4SS. RT-PCR reveals ribA and virB8-1 genes are co-transcribed as one operon, indicating the ribA gene and T4SS operon 1 are co-regulated by both wBmxR1 and wBmxR2. RibA encodes a bi-functional enzyme that catalyzes two essential steps in riboflavin (Vitamin B2) biosynthesis. Importantly, the riboflavin pathway is absent in B. malayi. We demonstrate the pathway is functional in wBm, and observe vitamin B2 supplementation partially rescues filarial parasites treated with doxycycline, indicating Wolbachia may supply the essential vitamin to its worm host. This is the first characterization of a transcription factor(s) from wBm and first report of co-regulation of genes of the T4SS and riboflavin biosynthesis pathway. In addition, our results demonstrate a requirement of vitamin B2 for worm health and fertility, and imply a nutritional role of the symbiont for the filarial parasite host. PMID:23251587

  13. Phlorizin, an Active Ingredient of Eleutherococcus senticosus, Increases Proliferative Potential of Keratinocytes with Inhibition of MiR135b and Increased Expression of Type IV Collagen

    PubMed Central

    Choi, Hye-Ryung; Nam, Kyung-Mi; Lee, Hyun-Sun; Yang, Seung-Hye; Kim, Young-Soo; Lee, Jongsung; Date, Akira; Toyama, Kazumi; Park, Kyoung-Chan

    2016-01-01

    E. senticosus extract (ESE), known as antioxidant, has diverse pharmacologic effects. It is also used as an antiaging agent for the skin and phlorizin (PZ) is identified as a main ingredient. In this study, the effects of PZ on epidermal stem cells were investigated. Cultured normal human keratinocytes and skin equivalents are used to test whether PZ affects proliferative potential of keratinocytes and how it regulates these effects. Skin equivalents (SEs) were treated with ESE and the results showed that the epidermis became slightly thickened on addition of 0.002% ESE. The staining intensity of p63 as well as proliferating cell nuclear antigen (PCNA) is increased, and integrin α6 was upregulated. Analysis of ESE confirmed that PZ is the main ingredient. When SEs were treated with PZ, similar findings were observed. In particular, the expression of integrin α6, integrin β1, and type IV collagen was increased. Levels of mRNA for type IV collagen were increased and levels of miR135b were downregulated. All these findings suggested that PZ can affect the proliferative potential of epidermal cells in part by microenvironment changes via miR135b downregulation and following increased expression of type IV collagen. PMID:27042261

  14. Endovenous surgery for recurrent varicose veins with a one-year follow up in a patient with Ehlers Danlos syndrome type IV.

    PubMed

    Whiteley, Mark S; Holdstock, Judith M

    2015-08-01

    We present a woman with severe symptomatic recurrent varicose veins who was treated with endovenous laser ablation and transluminal occlusion of perforator with attempted phlebectomies for extensive varices. The phlebectomies turned out to be near impossible due to friability of the veins. Her treatment was completed with post-operative ultrasound guided foam sclerotherapy seven months later. She was subsequently diagnosed as Ehlers Danlos syndrome type IV. A duplex ultrasound scan 18 months post-endovenous laser ablation and transluminal occlusion of perforator and 11 months after ultrasound guided foam sclerotherapy confirmed successful closure with virtual atrophy of all treated veins. She was found to be reflux free and only showed a few scattered cosmetic reticular veins. Open varicose vein surgery has been reported as being hazardous in the past in a patient with Ehlers Danlos syndrome type IV. Our experience has shown that endovenous laser ablation, transluminal occlusion of perforator and ultrasound guided foam sclerotherapy appear to be effective in treating this patient with Ehlers Danlos syndrome type IV, although phlebectomies were technically impossible. PMID:24714385

  15. Phlorizin, an Active Ingredient of Eleutherococcus senticosus, Increases Proliferative Potential of Keratinocytes with Inhibition of MiR135b and Increased Expression of Type IV Collagen.

    PubMed

    Choi, Hye-Ryung; Nam, Kyung-Mi; Lee, Hyun-Sun; Yang, Seung-Hye; Kim, Young-Soo; Lee, Jongsung; Date, Akira; Toyama, Kazumi; Park, Kyoung-Chan

    2016-01-01

    E. senticosus extract (ESE), known as antioxidant, has diverse pharmacologic effects. It is also used as an antiaging agent for the skin and phlorizin (PZ) is identified as a main ingredient. In this study, the effects of PZ on epidermal stem cells were investigated. Cultured normal human keratinocytes and skin equivalents are used to test whether PZ affects proliferative potential of keratinocytes and how it regulates these effects. Skin equivalents (SEs) were treated with ESE and the results showed that the epidermis became slightly thickened on addition of 0.002% ESE. The staining intensity of p63 as well as proliferating cell nuclear antigen (PCNA) is increased, and integrin α6 was upregulated. Analysis of ESE confirmed that PZ is the main ingredient. When SEs were treated with PZ, similar findings were observed. In particular, the expression of integrin α6, integrin β1, and type IV collagen was increased. Levels of mRNA for type IV collagen were increased and levels of miR135b were downregulated. All these findings suggested that PZ can affect the proliferative potential of epidermal cells in part by microenvironment changes via miR135b downregulation and following increased expression of type IV collagen. PMID:27042261

  16. Structure-activity relationships of aminocoumarin-type gyrase and topoisomerase IV inhibitors obtained by combinatorial biosynthesis.

    PubMed

    Flatman, Ruth H; Eustaquio, Alessandra; Li, Shu-Ming; Heide, Lutz; Maxwell, Anthony

    2006-04-01

    Novobiocin and clorobiocin are gyrase inhibitors produced by Streptomyces strains. Structurally, the two compounds differ only by substitution at two positions: CH3 versus Cl at position 8' of the aminocoumarin ring and carbamoyl versus 5-methyl-pyrrol-2-carbonyl (MePC) at the 3"-OH of noviose. Using genetic engineering, we generated a series of analogs carrying H, CH3, or Cl at 8' and H, carbamoyl, or MePC at 3"-OH. Comparison of the gyrase inhibitory activities of all nine structural permutations confirmed that acylation of 3"-OH is essential for activity, with MePC being more effective than carbamoyl. Substitution at 8' further enhanced activity, but the effect of CH3 or Cl depended on the nature of the acyl group at 3": in the presence of carbamoyl at 3", CH3 resulted in higher activity; in the presence of MePC at 3", Cl resulted in higher activity. This suggests that the structures of both natural compounds are highly evolved for optimal interaction with gyrase. In a second series of experiments, clorobiocin derivatives with and without the methyl group at 4"-OH of noviose, and with different positions of the MePC group of noviose, were tested. Again clorobiocin was superior to all of its analogs. The activities of all compounds were also tested against topoisomerase IV (topo IV). Clorobiocin stood out as a remarkably effective topo IV inhibitor. The relative activities of the different compounds toward topo IV showed a pattern similar to that of the relative gyrase-inhibitory activities. This is the first report of a systematic evaluation of a series of aminocoumarins against both gyrase and topo IV. The results give further insight into the structure-activity relationships of aminocoumarin antibiotics. PMID:16569821

  17. Molecular and structural analysis of Legionella DotI gives insights into an inner membrane complex essential for type IV secretion

    PubMed Central

    Kuroda, Takuya; Kubori, Tomoko; Thanh Bui, Xuan; Hyakutake, Akihiro; Uchida, Yumiko; Imada, Katsumi; Nagai, Hiroki

    2015-01-01

    The human pathogen Legionella pneumophila delivers a large array of the effector proteins into host cells using the Dot/Icm type IVB secretion system. Among the proteins composing the Dot/Icm system, an inner membrane protein DotI is known to be crucial for the secretion function but its structure and role in type IV secretion had not been elucidated. We report here the crystal structures of the periplasmic domains of DotI and its ortholog in the conjugation system of plasmid R64, TraM. These structures reveal a striking similarity to VirB8, a component of type IVA secretion systems, suggesting that DotI/TraM is the type IVB counterpart of VirB8. We further show that DotI and its partial paralog DotJ form a stable heterocomplex. R64 TraM, encoded by the conjugative plasmid lacking DotJ ortholog, forms a homo-hexamer. The DotI-DotJ complex is distinct from the core complex, which spans both inner and outer membranes to form a substrate conduit, and seems not to stably associate with the core complex. These results give insight into VirB8-family inner membrane proteins essential for type IV secretion and aid towards understanding the molecular basis of secretion systems essential for bacterial pathogenesis. PMID:26039110

  18. Autoepitopes and alloepitopes of type IV collagen: role in the molecular pathogenesis of anti-GBM antibody glomerulonephritis.

    PubMed

    Borza, Dorin-Bogdan

    2007-01-01

    Anti-glomerular basement membrane (anti-GBM) antibodies elicited by autoimmune or alloimmune mechanisms are associated with aggressive forms of rapid progressive glomerulonephritis. Pathogenic anti-GBM autoantibodies and alloantibodies target the noncollagenous (NC1) domains of the alpha3alpha4alpha5(IV) collagen, a major GBM component. In autoimmune anti-GBM glomerulonephritis, a breakdown of immune self-tolerance leads to the activation of autoreactive B and T cells recognizing epitopes within the alpha3NC1 subunit. In the GBM, the conformational epitopes targeted by anti-GBM autoantibodies are structurally sequestered within the alpha3alpha4alpha5NC1 hexamer complex formed upon assembly of collagen IV chains into trimeric molecules and networks. Autoantibodies selectively bind to and dissociate a subset of alpha3alpha4alpha5NC1 hexamers composed of monomer subunits, whereas hexamers containing NC1 dimer subunits are resistant to dissociation by autoantibodies. The crypticity of alpha3NC1 autoepitopes suggests that self-tolerance to alpha3(IV) collagen is broken by structural alterations of the native alpha3alpha4alpha5NC1 hexamer that unmask normally sequestered epitopes, triggering an autoimmune reaction. Post-transplant anti-GBM nephritis in the renal allograft of transplanted Alport patients is mediated by an alloimmune reaction to the NC1 domains of alpha3alpha4alpha5(IV) collagen, present in the allograft GBM but absent from Alport basement membranes. Alloantibodies from patients with autosomal-recessive Alport syndrome predominantly bind to the alpha3NC1 domain, whereas alloantibodies from X-linked Alport patients target preferentially, though not exclusively, epitopes within the alpha5NC1 subunit. The accessibility of the alloantigenic sites within the alpha3alpha4alpha5NC1 hexamers, contrasting with the crypticity of autoantigenic sites, suggest that different molecular forms of alpha3alpha4alpha5(IV) collagen initiate the immunopathogenic responses in

  19. EffectiveDB—updates and novel features for a better annotation of bacterial secreted proteins and Type III, IV, VI secretion systems

    PubMed Central

    Eichinger, Valerie; Nussbaumer, Thomas; Platzer, Alexander; Jehl, Marc-André; Arnold, Roland; Rattei, Thomas

    2016-01-01

    Protein secretion systems play a key role in the interaction of bacteria and hosts. EffectiveDB (http://effectivedb.org) contains pre-calculated predictions of bacterial secreted proteins and of intact secretion systems. Here we describe a major update of the database, which was previously featured in the NAR Database Issue. EffectiveDB bundles various tools to recognize Type III secretion signals, conserved binding sites of Type III chaperones, Type IV secretion peptides, eukaryotic-like domains and subcellular targeting signals in the host. Beyond the analysis of arbitrary protein sequence collections, the new release of EffectiveDB also provides a ‘genome-mode’, in which protein sequences from nearly complete genomes or metagenomic bins can be screened for the presence of three important secretion systems (Type III, IV, VI). EffectiveDB contains pre-calculated predictions for currently 1677 bacterial genomes from the EggNOG 4.0 database and for additional bacterial genomes from NCBI RefSeq. The new, user-friendly and informative web portal offers a submission tool for running the EffectiveDB prediction tools on user-provided data. PMID:26590402

  20. Magnetic effects in anomalous dispersion

    SciTech Connect

    Blume, M.

    1992-12-31

    Spectacular enhancements of magnetic x-ray scattering have been predicted and observed experimentally. These effects are the result of resonant phenomena closely related to anomalous dispersion, and they are strongest at near-edge resonances. The theory of these resonances will be developed with particular attention to the symmetry properties of the scatterer. While the phenomena to be discussed concern magnetic properties the transitions are electric dipole or electric quadrupole in character and represent a subset of the usual anomalous dispersion phenomena. The polarization dependence of the scattering is also considered, and the polarization dependence for magnetic effects is related to that for charge scattering and to Templeton type anisotropic polarization phenomena. It has been found that the strongest effects occur in rare-earths and in actinides for M shell edges. In addition to the scattering properties the theory is applicable to ``forward scattering`` properties such as the Faraday effect and circular dichroism.

  1. Non-oxido divanadium(IV) and divanadium(V) thiolate complexes with a new type of chalcogenide bridging motif.

    PubMed

    Wu, Hong-Ming; Chang, Ya-Ho; Tsai, Yi-Fang; Hsu, Kuei-Fang; Lee, Gene-Hsiang; Hsu, Hua-Fen

    2015-03-14

    In our effort to study vanadium chalcogenide chemistry, we have synthesized and characterized a class of non-oxido divanadium(IV) and divanadium(V) complexes with chalcogenide and dichalcogenide as bridges. All structures consist of a similar divanadium motif, in which two metal centers are bridged by one μ-chalcogenide and one μ-η(2):η(2)-dichalcogenide, forming a V2(μ-E)(μ-η(2):η(2)-E2) (E = S or Se) core structure. These compounds are [V(IV)2(PS3)2(μ-Se2)(μ-Se)][PPh4]2 (1), [V(V)2(PS3'')2(μ-Se2)(μ-Se)] (2), [V(V)2(PS3'')2(μ-S2)(μ-S)] (3a) and [V(V)2(PS3)2(μ-S2)(μ-S)] (3b) ([PS3](3-) = P(C6H4-2-S)3 and [PS3''](3-) = P(C6H3-3-SiMe3-2-S)3). Compound 1 exhibits diamagnetic behavior, indicating strong antiferromagnetic coupling between two d(1) centers. Compounds 2 and 3a-b have the highest oxidation states for vanadium ions (+5/+5) among those reported divanadium chalcogenide clusters. The work demonstrates that high-valent divanadium chalcogenide clusters can be obtained with the activation of elemental chalcogens by low-valent vanadium ions. PMID:25645817

  2. The charmonium dissociation in an ''anomalous wind''

    DOE PAGESBeta

    Sadofyev, Andrey V.; Yin, Yi

    2016-01-11

    We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and it qualitative difference between anomalous effects on the charmoniummore » color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. As a result, we speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.« less

  3. The charmonium dissociation in an "anomalous wind"

    NASA Astrophysics Data System (ADS)

    Sadofyev, Andrey V.; Yin, Yi

    2016-01-01

    We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and qualitative difference between anomalous effects on the charmonium color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.

  4. Highly Isospecific Polymerization of Silyl-Protected ω-Alkenols Using an [OSSO]-Type Bis(phenolato) Dichloro Zirconium(IV) Precatalyst.

    PubMed

    Saito, Yusuke; Nakata, Norio; Ishii, Akihiko

    2016-06-01

    The coordination polymerization of silyl-protected ω-alkenols such as ω-alken-α-oxytriisopropylsilanes 1 provides poly(ω-alkenyl-α-oxytriisopropylsilalne)s with a highly isospecific microstructure ([mmmm] > 95%) when a combination of [OSSO]-type bis(phenolato) dichloro zirconium(IV) complex 2 and dried methylaluminoxane is used as the precatalyst and activator, respectively. The resulting siloxy-substituted polymers could be efficiently transformed into the corresponding functionalized polyolefins, which contained up to 90% acetyl groups and ≈7% hydroxy groups in the terminal side chains. PMID:27150730

  5. Incidence and specificity of antibodies to types I, II, III, IV, and V collagen in rheumatoid arthritis and other rheumatic diseases as measured by 125I-radioimmunoassay

    SciTech Connect

    Stuart, J.M.; Huffstutter, E.H.; Townes, A.S.; Kang, A.H.

    1983-07-01

    Antibodies to human native and denatured types I, II, III, IV, and V collagens were measured using 125I-radioimmunoassay. Mean levels of binding by sera from 30 rheumatoid arthritis patients were significantly higher than those from 20 normal subjects against all of the collagens tested. The relative antibody concentration was higher in synovial fluid than in simultaneously obtained serum. Many patients with gout or various other rheumatic diseases also had detectable anticollagen antibodies. With a few notable exceptions, the majority of the reactivity detected in all patient groups was directed against covalent structural determinants present on all of the denatured collagens, suggesting a secondary reaction to tissue injury.

  6. Anomalous discrete symmetry

    SciTech Connect

    Huang, Z. )

    1992-12-01

    We examine an interesting scenario to solve the domain-wall problem recently suggested by Preskill, Trivedi, Wilczek, and Wise. The effective potential is calculated in the presence of the QCD axial anomaly. It is shown that some discrete symmetries such as {ital CP} and {ital Z}{sub 2} can be anomalous due to a so-called {ital K} term induced by instantons. We point out that the {ital Z}{sub 2} domain-wall problem in the two-doublet standard model can be resolved by two types of solutions: the {ital CP}-conserving one and the {ital CP}-breaking one. In the first case, there exist two {ital Z}{sub 2}-related local minima whose energy splitting is provided by the instanton effect. In the second case, there is only one unique vacuum so that the domain walls do not form at all. The consequences of this new source of {ital CP} violation are discussed and shown to be well within the experimental limits in weak interactions.

  7. Bradykinin-induced modulation of the response behaviour of different types of feline group III and IV muscle receptors.

    PubMed Central

    Mense, S; Meyer, H

    1988-01-01

    1. In order to test the hypothesis that bradykinin has a sensitizing action on muscle receptors (e.g. during a myositis), the response properties of single group III and IV afferent units from the cat gastrocnemius-soleus muscle were compared before and after infiltration of their receptive fields with a bradykinin solution. According to their responses to graded natural stimuli (local pressure, stretch, contractions and temperature changes) the units were classified as (a) nociceptors, (b) low-threshold pressure-sensitive (LTP) receptors, (c) contraction-sensitive (CS) receptors and (d) thermosensitive receptors. 2. Bradykinin activated the majority of both the nociceptive and low-threshold (LTP, CS and thermosensitive) receptors but a sensitization was prominent only among the nociceptors. Most of the sensitized nociceptors showed increased responses to mechanical, but not to thermal, stimuli. The sensitization appeared to be quite specific in that the nociceptors were sensitized either towards local pressure stimulation or to active contractions, but never towards both forms of stimulation. 3. Both group III and group IV nociceptors were sensitized by bradykinin, the proportion of sensitized receptors being greater for group III units. 4. Some of the low-threshold receptors (particularly the CS units) showed a desensitization under the influence of bradykinin. 5. Although bradykinin (by lowering the mechanical thresholds of nociceptors into the innocuous range) could produce the symptom of allodynia, it was not capable of eliciting all the changes in receptor behaviour which are known to occur in inflamed tissues. For instance, no ongoing activity of longer duration and no substantial sensitization of low-threshold receptors have been observed in the present study. PMID:3392680

  8. On Anomalous Quark Triangles

    NASA Astrophysics Data System (ADS)

    Vainshtein, Arkady

    2011-04-01

    Anomalous quark triangles with one axial and two vector currents are studied in special kinematics when one of the vector currents carries a soft momentum. According to the Adler-Bardeen theorem the anomalous longitudinal part of the triangle is not renormalized in the chiral limit. We show that perturbative corrections the transversal part of the triangle is also absent. This nonrenormalization, in difference with the longitudinal part, holds on only perturbatively.

  9. Prevalence and clonality of methicillin-resistant Staphylococcus aureus (MRSA) in the Atlantic Azores islands: predominance of SCCmec types IV, V and VI.

    PubMed

    Conceição, T; Tavares, A; Miragaia, M; Hyde, K; Aires-de-Sousa, M; de Lencastre, H

    2010-05-01

    In order to obtain insights into the methicillin-resistant Staphylococcus aureus (MRSA) population structure in the Azores archipelago, 106 MRSA isolates were collected from patients attending an Azorean central hospital between January 2007 and February 2008. Antimicrobial resistance was determined for all isolates. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE), spa typing, multilocus sequence typing (MLST), staphylococcal chromosome cassette mec (SCCmec) typing and the presence of Panton-Valentine leukocidin (PVL). The majority of the isolates (87%, n = 92) belonged to the EMRSA-15 clone (ST22, SCCmec-IVh), followed by the Pediatric clone (ST5-VI/IVc) (11%, n = 12). The Berlin clone (ST45-IVa) and a new clone (spa type t1839, ST1339 and SCCmec V variant) were represented by single isolates. All of the isolates carried SCCmec types IV, V or VI and a non-multiresistant antibiotic profile, resembling the currently emerging community MRSA. Moreover, PVL was described for the first time to be associated with the Pediatric clone carrying SCCmec type VI. We provided the first description of the population structure of MRSA in the Azores islands, which seems to be shaped by genetic events occurring locally, as well as by the regular population exchange between the islands, continental Portugal, the United Kingdom and the United States. PMID:20229224

  10. Anomalous is ubiquitous

    SciTech Connect

    Eliazar, Iddo; Klafter, Joseph

    2011-09-15

    Brownian motion is widely considered the quintessential model of diffusion processes-the most elemental random transport processes in Science and Engineering. Yet so, examples of diffusion processes displaying highly non-Brownian statistics-commonly termed 'Anomalous Diffusion' processes-are omnipresent both in the natural sciences and in engineered systems. The scientific interest in Anomalous Diffusion and its applications is growing exponentially in the recent years. In this Paper we review the key statistics of Anomalous Diffusion processes: sub-diffusion and super-diffusion, long-range dependence and the Joseph effect, Levy statistics and the Noah effect, and 1/f noise. We further present a theoretical model-generalizing the Einstein-Smoluchowski diffusion model-which provides a unified explanation for the prevalence of Anomalous Diffusion statistics. Our model shows that what is commonly perceived as 'anomalous' is in effect ubiquitous. - Highlights: > The article provides an overview of Anomalous Diffusion (AD) statistics. > The Einstein-Smoluchowski diffusion model is extended and generalized. > The generalized model universally generates AD statistics. > A unified 'universal macroscopic explanation' for AD statistics is established. > AD statistics are shown to be fundamentally connected to robustness.

  11. Secondary flow structures in the presence of Type-IV stent fractures through a bent tube model for curved arteries: Effect of circulation thresholding

    NASA Astrophysics Data System (ADS)

    Hussain, Shadman; Bulusu, Kartik V.; Plesniak, Michael W.

    2013-11-01

    A common treatment for atherosclerosis is the opening of narrowed arteries resulting from obstructive lesions by angioplasty and stent implantation to restore unrestricted blood flow. ``Type-IV'' stent fractures involve complete transverse, linear fracture of stent struts, along with displacement of the stent fragments. Experimental data pertaining to secondary flows in the presence of stents that underwent ``Type-IV'' fractures in a bent artery model under physiological inflow conditions were obtained through a two-component, two-dimensional (2C-2D) PIV technique. Concomitant stent-induced flow perturbations result in secondary flow structures with complex, multi-scale morphologies and varying size-strength characteristics. Ultimately, these flow structures may have a role to play in restenosis and progression of atherosclerotic plaque. Vortex circulation thresholds were established with the goal of resolving and tracking iso-circulation secondary flow vortical structures and their morphological changes. This allowed for a parametric evaluation and quantitative representation of secondary flow structures undergoing deformation and spatial reorganization. Supported by NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

  12. Phosphoproteomic Analysis Reveals the Effects of PilF Phosphorylation on Type IV Pilus and Biofilm Formation in Thermus thermophilus HB27*

    PubMed Central

    Wu, Wan-Ling; Liao, Jiahn-Haur; Lin, Guang-Huey; Lin, Miao-Hsia; Chang, Ying-Che; Liang, Suh-Yuen; Yang, Feng-Ling; Khoo, Kay-Hooi; Wu, Shih-Hsiung

    2013-01-01

    Thermus thermophilus HB27 is an extremely thermophilic eubacteria with a high frequency of natural competence. This organism is therefore often used as a thermophilic model to investigate the molecular basis of type IV pili–mediated functions, such as the uptake of free DNA, adhesion, twitching motility, and biofilm formation, in hot environments. In this study, the phosphoproteome of T. thermophilus HB27 was analyzed via a shotgun approach and high-accuracy mass spectrometry. Ninety-three unique phosphopeptides, including 67 in vivo phosphorylated sites on 53 phosphoproteins, were identified. The distribution of Ser/Thr/Tyr phosphorylation sites was 57%/36%/7%. The phosphoproteins were mostly involved in central metabolic pathways and protein/cell envelope biosynthesis. According to this analysis, the ATPase motor PilF, a type IV pili–related component, was first found to be phosphorylated on Thr-368 and Ser-372. Through the point mutation of PilF, mimic phosphorylated mutants T368D and S372E resulted in nonpiliated and nontwitching phenotypes, whereas nonphosphorylated mutants T368V and S372A displayed piliation and twitching motility. In addition, mimic phosphorylated mutants showed elevated biofilm-forming abilities with a higher initial attachment rate, caused by increasing exopolysaccharide production. In summary, the phosphorylation of PilF might regulate the pili and biofilm formation associated with exopolysaccharide production. PMID:23828892

  13. Characterization of Microstructures across the Heat-Affected Zone of the Modified 9Cr-1Mo Weld Joint to Understand Its Role in Promoting Type IV Cracking

    NASA Astrophysics Data System (ADS)

    Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Rao, K. Bhanu Sankara; Mannan, S. L.

    2007-01-01

    In the postweld heat-treated (PWHT) fusion welded modified 9Cr-1Mo steel joint, a soft zone was identified at the outer edge of the heat-affected zone (HAZ) of the base metal adjacent to the deposited weld metal. Hardness and tensile tests were performed on the base metal subjected to soaking for 5 minutes at temperatures below Ac1 to above Ac3 and tempering at the PWHT condition. These tests indicated that the soft zone in the weld joint corresponds to the intercritical region of HAZ. Creep tests were conducted on the base metal and cross weld joint. At relatively lower stresses and higher test temperatures, the weld joint possessed lower creep rupture life than the base metal, and the difference in creep rupture life increased with the decrease in stress and increase in temperature. Preferential accumulation of creep deformation coupled with extensive creep cavitation in the intercritical region of HAZ led to the premature failure of the weld joint in the intercritical region of the HAZ, commonly known as type IV cracking. The microstructures across the HAZ of the weld joint have been characterized to understand the role of microstructure in promoting type IV cracking. Strength reduction in the intercritical HAZ of the joint resulted from the combined effects of coarsening of dislocation substructures and precipitates. Constrained deformation of the soft intercritical HAZ sandwich between relatively stronger constitutes of the joint induced creep cavitation in the soft zone resulting in premature failure.

  14. Vibrio parahaemolyticus type IV pili mediate interactions with diatom-derived chitin and point to an unexplored mechanism of environmental persistence.

    PubMed

    Frischkorn, Kyle R; Stojanovski, Asta; Paranjpye, Rohinee

    2013-05-01

    Vibrio parahaemolyticus is a naturally occurring bacterium common in coastal waters where it concentrates in shellfish through filter feeding. The bacterium is a human pathogen and the leading cause of seafood-borne gastroenteritis. Presently there is little information regarding mechanisms of environmental persistence of V.parahaemolyticus or an accurate early warning system for outbreak prediction. Vibrios have been shown to adhere to several substrates in the environment, including chitin, one of the most abundant polymers in the ocean. Diatoms are abundant in estuarine waters and some species produce chitin as a component of the silica cell wall or as extracellular fibrils. We examined the role of specific surface structures on the bacterium, the type IV pilins PilA and MshA, in adherence to diatom-derived chitin. Biofilm formation and adherence of V.parahaemolyticus to chitin is mediated by the ability of the bacterium to express functional type IV pili. The amount of adherence to diatom-derived chitin is controlled by increased chitin production that occurs in later stages of diatom growth. The data presented here suggest late-stage diatom blooms may harbour high concentrations of V.parahaemolyticus and could serve as the foundation for a more accurate early warning system for outbreaks of this human pathogen. PMID:23441888

  15. Identification of the NC1 Domain of α3 Chain as Critical for α3α4α5 Type IV Collagen Network Assembly

    PubMed Central

    LeBleu, Valerie; Sund, Malin; Sugimoto, Hikaru; Birrane, Gabriel; Kanasaki, Keizo; Finan, Elizabeth; Miller, Caroline A.; Gattone, Vincent H.; McLaughlin, Heather; Shield, Charles F.; Kalluri, Raghu

    2010-01-01

    The network organization of type IV collagen consisting of α3, α4, and α5 chains in the glomerular basement membrane (GBM) is speculated to involve interactions of the triple helical and NC1 domain of individual α-chains, but in vivo evidence is lacking. To specifically address the contribution of the NC1 domain in the GBM collagen network organization, we generated a mouse with specific loss of α3NC1 domain while keeping the triple helical α3 chain intact by connecting it to the human α5NC1 domain. The absence of α3NC1 domain leads to the complete loss of the α4 chain. The α3 collagenous domain is incapable of incorporating the α5 chain, resulting in the impaired organization of the α3α4α5 chain-containing network. Although the α5 chain can assemble with the α1, α2, and α6 chains, such assembly is incapable of functionally replacing the α3α4α5 protomer. This novel approach to explore the assembly type IV collagen in vivo offers novel insights in the specific role of the NC1 domain in the assembly and function of GBM during health and disease. PMID:20847057

  16. Type IV prepilin peptidase gene of Neisseria gonorrhoeae MS11: presence of a related gene in other piliated and nonpiliated Neisseria strains.

    PubMed Central

    Dupuy, B; Pugsley, A P

    1994-01-01

    The assembly of type IV pili in Neisseria gonorrhoeae is a complex process likely to require the products of many genes. One of these is the enzyme prepilin peptidase, which cleaves and then N methylates the precursor pilin subunits prior to their assembly into pili. We have used a PCR amplification strategy to clone the N. gonorrhoeae prepilin peptidase gene, pilDNg. A single copy of the gene is shown to be present in the chromosome. Its product promotes correct cleavage of the gonococcal prepillin in Escherichia coli cells carrying both the prepilin peptidase gene and the pilin structural gene. PilDNg also cleaves prePulG, a type IV pilin-like protein of Klebsiella oxytoca. Moreover, PilDNg complements a mutation in the gene coding for the prepilin peptidase-like protein of K. oxytoca, pulO, partially restoring PulG-PulO-dependent extracellular secretion of the enzyme pullulanase. Finally, we show that genes homologous to pilDNg are present and expressed in a variety of species in the genus Neisseria, including some commensal strains. Images PMID:7906688

  17. Hydrocortisone modulates the expression of c-ets-1 and 72 kDa type IV collagenase in chicken dermis during early feather morphogenesis.

    PubMed

    Turque, N; Buttice, G; Beuscart, A; Stehelin, D; Crepieux, P; Desbiens, X

    1997-02-01

    At the onset of chicken feather morphogenesis, dermal cells migrate along bundles of collagen fibers to colonize areas where bud outgrowth takes place. Chicken embryos treated with hydrocortisone during the critical phase of dermal rearrangement show featherless skin areas in which the dermis exhibits an increase of interstitial collagen. We had previously demonstrated that c-ets-1 is a nuclear transcription factor expressed in the dermis at the beginning of feather morphogenesis. Here we study, by in situ mRNA hybridization, the expression of c-ets-1 in the dermis of chicken embryos treated with hydrocortisone. We found that, among the two distinct products (p54 and p68) encoded by the chicken c-ets-1, the expression of the p68 product increased while expression of p54 decreased after hydrocortisone treatment. Since Ets-1 regulates matrix-metalloproteinases genes, we analyzed the expression of the 72 kDa type IV collagenase in both normal and hydrocortisone-treated embryos. We demonstrated that 72 kDa type IV collagenase mRNA expression decreased in the dermis after hydrocortisone treatment and that its expression correlated with that of p54c-ets-1. Taken together, these results indicate that hydrocortisone modulates c-ets-1 expression. In addition, they raise the interesting possibility that c-ets-1 might be involved in an altered pattern of feather development mediated by the accumulation of collagen due to a decrease in collagenase activities. PMID:9074942

  18. Serum Levels of Soluble CD26/Dipeptidyl Peptidase-IV in Type 2 Diabetes Mellitus and Its Association with Metabolic Syndrome and Therapy with Antidiabetic Agents in Malaysian Subjects

    PubMed Central

    Ahmed, Radwan H.; Huri, Hasniza Zaman; Al-Hamodi, Zaid; Salem, Sameer D.; Muniandy, Sekaran

    2015-01-01

    Background A soluble form of CD26/dipeptidyl peptidase-IV (sCD26/DPP-IV) induces DPP-IV enzymatic activity that degrades incretin. We investigated fasting serum levels of sCD26/DPP-IV and active glucagon-like peptide-1 (GLP-1) in Malaysian patients with type 2 diabetes mellitus (T2DM) with and without metabolic syndrome (MetS), as well as the associations between sCD26/DPP-IV levels, MetS, and antidiabetic therapy. Methods We assessed sCD26/DPP-IV levels, active GLP-1 levels, body mass index (BMI), glucose, insulin, A1c, glucose homeostasis indices, and lipid profiles in 549 Malaysian subjects (including 257 T2DM patients with MetS, 57 T2DM patients without MetS, 71 non-diabetics with MetS, and 164 control subjects without diabetes or metabolic syndrome). Results Fasting serum levels of sCD26/DPP-IV were significantly higher in T2DM patients with and without MetS than in normal subjects. Likewise, sCD26/DPP-IV levels were significantly higher in patients with T2DM and MetS than in non-diabetic patients with MetS. However, active GLP-1 levels were significantly lower in T2DM patients both with and without MetS than in normal subjects. In T2DM subjects, sCD26/DPP-IV levels were associated with significantly higher A1c levels, but were significantly lower in patients using monotherapy with metformin. In addition, no significant differences in sCD26/DPP-IV levels were found between diabetic subjects with and without MetS. Furthermore, sCD26/DPP-IV levels were negatively correlated with active GLP-1 levels in T2DM patients both with and without MetS. In normal subjects, sCD26/DPP-IV levels were associated with increased BMI, cholesterol, and LDL-cholesterol (LDL-c) levels. Conclusion Serum sCD26/DPP-IV levels increased in T2DM subjects with and without MetS. Active GLP-1 levels decreased in T2DM patients both with and without MetS. In addition, sCD26/DPP-IV levels were associated with Alc levels and negatively correlated with active GLP-1 levels. Moreover, metformin

  19. A Posteriorly Displaced Distal Metaphyseal Clavicular Fracture (Type IV AC Joint Dislocation-Like) in Children: A Case Report and Literature Review Study.

    PubMed

    Kotb, Ahmed; Yong, Taylor; Abdelgawad, Amr

    2016-01-01

    Fractures of the lateral end of the clavicle are common in pediatric patients; most of these fractures occur at the physeal level representing Salter Harris injuries. The vast majority of fractures of the lateral end of the clavicle are managed nonoperatively. In this report, we describe a unique type of fracture of the distal end of the clavicle in the pediatric patients in which the fracture occurs in the metaphyseal lateral clavicle with the proximal edge of the fracture displaced posteriorly through the trapezius muscle causing obvious deformity. It is similar in pathology to type IV AC joint dislocation. In this study we report this injury in eleven-year-old boy. Literature review showed that similar injuries were described before three times (two of them in pediatric patients). Due to the significant clinical deformity of this category with entrapment of the bone through the trapezius muscle, reduction (open or closed) of the fracture is the recommended treatment. PMID:26904336

  20. A Posteriorly Displaced Distal Metaphyseal Clavicular Fracture (Type IV AC Joint Dislocation-Like) in Children: A Case Report and Literature Review Study

    PubMed Central

    Kotb, Ahmed; Yong, Taylor; Abdelgawad, Amr

    2016-01-01

    Fractures of the lateral end of the clavicle are common in pediatric patients; most of these fractures occur at the physeal level representing Salter Harris injuries. The vast majority of fractures of the lateral end of the clavicle are managed nonoperatively. In this report, we describe a unique type of fracture of the distal end of the clavicle in the pediatric patients in which the fracture occurs in the metaphyseal lateral clavicle with the proximal edge of the fracture displaced posteriorly through the trapezius muscle causing obvious deformity. It is similar in pathology to type IV AC joint dislocation. In this study we report this injury in eleven-year-old boy. Literature review showed that similar injuries were described before three times (two of them in pediatric patients). Due to the significant clinical deformity of this category with entrapment of the bone through the trapezius muscle, reduction (open or closed) of the fracture is the recommended treatment. PMID:26904336

  1. Salter-Harris type III and IV displaced fracture of the hallux in young gymnasts: A series of four cases at 1-year follow-up.

    PubMed

    Perugia, Dario; Fabbri, Mattia; Guidi, Marco; Lepri, Marco; Masi, Vincenzo

    2014-12-01

    The purpose of this study was to describe four exceptional cases of Salter-Harris type III and IV fractures of the proximal phalanx of the hallux in young high-level gymnasts. All gymnasts underwent the same mechanism of injury of hyperadduction, which indicates a role of the abductor hallucis muscle in the genesis and displacement of these fractures. An open reduction and internal fixation was performed to achieve an anatomical reduction and avoid chronic disability. At 1-year follow-up, all patients had an excellent American Orthopaedic Foot and Ankle Society (AOFAS) score (100 points), and there was no shortening or angulation of the first ray and no evidence of degenerative joint disease on X-ray. Moreover, all the gymnasts had returned to pre-injury levels of sporting activity. To our knowledge, there are no previous studies that address these types of injuries and how they are handled in gymnasts. PMID:25457317

  2. Anomalous physical properties of Heusler-type Co2Cr (Ga,Si) alloys and thermodynamic study on reentrant martensitic transformation

    NASA Astrophysics Data System (ADS)

    Xu, Xiao; Nagasako, Makoto; Kataoka, Mitsuo; Umetsu, Rie Y.; Omori, Toshihiro; Kanomata, Takeshi; Kainuma, Ryosuke

    2015-03-01

    Electronic, magnetic, and thermodynamic properties of Co2Cr(Ga,Si) -based shape-memory alloys, which exhibit reentrant martensitic transformation (RMT) behavior, were studied experimentally. For electric resistivity (ER), an inverse (semiconductor-like) temperature dependence in the parent phase was found, along with anomalous behavior below its Curie temperature. A pseudobinary phase diagram was determined, which gives a "martensite loop" clearly showing the reentrant behavior. Differential scanning calorimetry and specific-heat measurements were used to derive the entropy change Δ S between martensite and parent phases. The temperature dependence of the derived Δ S was analyzed thermodynamically to confirm the appearances of both the RMT and normal martensitic transformation. Detailed studies on the specific heat in martensite and parent phases at low temperatures were also conducted.

  3. Improvement of diabetes, obesity and hypertension in type 2 diabetic KKA{sup y} mice by bis(allixinato)oxovanadium(IV) complex

    SciTech Connect

    Adachi, Yusuke; Yoshikawa, Yutaka; Yoshida, Jiro; Kodera, Yukihiro . E-mail: kodera_y@wakunaga.co.jp; Katoh, Akira . E-mail: katoh@st.seikei.ac.jp; Takada, Jitsuya . E-mail: takada@hl.rri.kyoto-u.ac.jp; Sakurai, Hiromu . E-mail: sakurai@mb.kyoto-phu.ac.jp

    2006-07-07

    Previously, we found that bis(allixinato)oxovanadium(IV) (VO(alx){sub 2}) exhibits a potent hypoglycemic activity in type 1-like diabetic mice. Since the enhancement of insulin sensitivity is involved in one of the mechanisms by which vanadium exerts its anti-diabetic effects, VO(alx){sub 2} was further tested in type 2 diabetes with low insulin sensitivity. The effect of oral administration of VO(alx){sub 2} was examined in obesity-linked type 2 diabetic KKA{sup y} mice. Treatment of VO(alx){sub 2} for 4 weeks normalized hyperglycemia, glucose intolerance, hyperinsulinemia, hypercholesterolemia and hypertension in KKA{sup y} mice; however, it had no effect on hypoadiponectinemia. VO(alx){sub 2} also improved hyperleptinemia, following attenuation of obesity in KKA{sup y} mice. This is the first example in which a vanadium compound improved leptin resistance in type 2 diabetes by oral administration. On the basis of these results, VO(alx){sub 2} is proposed to enhance not only insulin sensitivity but also leptin sensitivity, which in turn improves diabetes, obesity and hypertension in an obesity-linked type 2 diabetic animal.

  4. Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. IV. The Fourth Year (2011-2012)

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Hambsch, Franz-Josef; Maehara, Hiroyuki; Masi, Gianluca; Miller, Ian; Noguchi, Ryo; Akasaka, Chihiro; Aoki, Tomoya; Kobayashi, Hiroshi; Matsumoto, Katsura; Nakagawa, Shinichi; Nakazato, Takuma; Nomoto, Takashi; Ogura, Kazuyuki; Ono, Rikako; Taniuchi, Keisuke; Stein, William; Henden, Arne; de Miguel, Enrique Kiyota, Seiichiro; Dubovsky, Pavol A.; Kudzej, Igor; Imamura, Kazuyoshi; Akazawa, Hidehiko; Takagi, Ryosuke; Wakabayashi, Yuya; Ogi, Minako; Tanabe, Kenji; Ulowetz, Joseph; Morelle, Etienne; Pickard, Roger D.; Ohshima, Tomohito; Kasai, Kiyoshi; Pavlenko, Elena P.; Antonyuk, Oksana I.; Baklanov, Aleksei V.; Antonyuk, Kirill; Samsonov, Denis; Pit, Nikolaj; Sosnovskij, Aleksei; Littlefield, Colin; Sabo, Richard; Ruiz, Javier; Krajci, Thomas; Dvorak, Shawn; Oksanen, Arto; Hirosawa, Kenji; Goff, William N.; Monard, Berto; Shears, Jeremy; Boyd, David; Voloshina, Irina B.; Shugarov, Sergey Yu.; Chochol, Drahomir; Miyashita, Atsushi; Pietz, Jochen; Katysheva, Natalia; Itoh, Hiroshi; Bolt, Greg; Andreev, Maksim V.; Parakhin, Nikolai; Malanushenko, Viktor; Martinelli, Fabio; Denisenko, Denis; Stockdale, Chris; Starr, Peter; Simonsen, Mike; Tristram, Paul J.; Fukui, Akihiko; Tordai, Tamas; Fidrich, Robert; Paxson, Kevin B.; Itagaki, Koh-ichi; Nakashima, Youichirou; Yoshida, Seiichi; Nishimura, Hideo; Kryachko, Timur V.; Samokhvalov, Andrey V.; Korotkiy, Stanislav A.; Satovski, Boris L.; Stubbings, Rod; Poyner, Gary; Muyllaert, Eddy; Gerke, Vladimir; MacDonald, Walter, II; Linnolt, Michael; Maeda, Yutaka; Hautecler, Hubert

    2013-02-01

    Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 86 SU UMa-type dwarf novae, mainly observed during the 2011-2012 season. We confirmed general trends recorded in our previous studies, such as the relation between period derivatives and orbital periods. There are some systems showing positive period derivatives despite the long orbital period. We observed the 2011 outburst of the WZ Sge-type dwarf nova BW Scl, and recorded an O - C diagram similar to those of previously known WZ Sge-type dwarf novae. The WZ Sge-type dwarf nova OT J184228.1+483742 showed an unusual pattern of double outbursts composed of an outburst with early superhumps and one with ordinary superhumps. We propose an interpretation that a very small growth rate of the 3:1 resonance due to an extremely low mass-ratio led to quenching the superoutburst before the ordinary superhump appeared. We systematically studied ER UMa-type dwarf novae, and found that V1159 Ori showed positive superhumps similar to ER UMa in the 1990s. The recently recognized ER UMa-type object BK Lyn dominantly showed negative superhumps, and its behavior was very similar to the present-day state of ER UMa. The pattern of period variations in AM CVn-type objects was very similar to that of short-period hydrogen-rich SU UMa-type dwarf novae, making them a helium analogue of hydrogen-rich SU UMa-type dwarf novae. SBS 1108+574, a peculiar hydrogen-rich dwarf nova below the period minimum, showed a very similar pattern of period variations to those of short-period SU UMa-type dwarf novae. The mass-ratio derived from the detected orbital period suggests that this secondary is a somewhat evolved star whose hydrogen envelope was mostly stripped during the mass-exchange. CC Scl, MASTER OT J072948.66+593824.4, and OT J173516.9+154708 showed only low-amplitude superhumps with complex profiles. These superhumps are likely to be a combination of two closely separated periods.

  5. Genetic and Mechanistic Evaluation for the Mixed-Field Agglutination in B3 Blood Type with IVS3+5G>A ABO Gene Mutation

    PubMed Central

    Wang, Wei-Ting; Sun, Chien-Feng

    2012-01-01

    Background The ABO blood type B3 is the most common B subtype in the Chinese population with a frequency of 1/900. Although IVS3+5G>A (rs55852701) mutation of B gene has been shown to associate with the development of B3 blood type, genetic and mechanistic evaluation for the unique mixed-field agglutination phenotype has not yet been completely addressed. Methodology/Principal Findings In this study, we analyzed 16 cases of confirmed B3 individuals and found that IVS3+5G>A attributes to all cases of B3. RT-PCR analyses revealed the presence of at least 7 types of aberrant B3 splicing transcripts with most of the transcripts causing early termination and producing non-functional protein during translation. The splicing transcript without exon 3 that was predicted to generate functional B3 glycosyltransferase lacking 19 amino acids at the N-terminal segment constituted only 0.9% of the splicing transcripts. Expression of the B3 cDNA with exon 3 deletion in the K562 erythroleukemia cells revealed that the B3 glycosyltransferase had only 40% of B1 activity in converting H antigen to B antigen. Notably, the typical mixed-field agglutination of B3-RBCs can be mimicked by adding anti-B antibody to the K562-B3 cells. Conclusions/Significance This study thereby demonstrates that both aberrant splicing of B transcripts and the reduced B3 glycosyltransferase activity contribute to weak B expression and the mixed-field agglutination of B3, adding to the complexity for the regulatory mechanisms of ABO gene expression. PMID:22624005

  6. Novel form of X-linked nonsyndromic hearing loss with cochlear malformation caused by a mutation in the type IV collagen gene COL4A6

    PubMed Central

    Rost, Simone; Bach, Elisa; Neuner, Cordula; Nanda, Indrajit; Dysek, Sandra; Bittner, Reginald E; Keller, Alexander; Bartsch, Oliver; Mlynski, Robert; Haaf, Thomas; Müller, Clemens R; Kunstmann, Erdmute

    2014-01-01

    Hereditary hearing loss is the most common human sensorineural disorder. Genetic causes are highly heterogeneous, with mutations detected in >40 genes associated with nonsyndromic hearing loss, to date. Whereas autosomal recessive and autosomal dominant inheritance is prevalent, X-linked forms of nonsyndromic hearing impairment are extremely rare. Here, we present a Hungarian three-generation family with X-linked nonsyndromic congenital hearing loss and the underlying genetic defect. Next-generation sequencing and subsequent segregation analysis detected a missense mutation (c.1771G>A, p.Gly591Ser) in the type IV collagen gene COL4A6 in all affected family members. Bioinformatic analysis and expression studies support this substitution as being causative. COL4A6 encodes the alpha-6 chain of type IV collagen of basal membranes, which forms a heterotrimer with two alpha-5 chains encoded by COL4A5. Whereas mutations in COL4A5 and contiguous X-chromosomal deletions involving COL4A5 and COL4A6 are associated with X-linked Alport syndrome, a nephropathy associated with deafness and cataract, mutations in COL4A6 alone have not been related to any hereditary disease so far. Moreover, our index patient and other affected family members show normal renal and ocular function, which is not consistent with Alport syndrome, but with a nonsyndromic type of hearing loss. In situ hybridization and immunostaining demonstrated expression of the COL4A6 homologs in the otic vesicle of the zebrafish and in the murine inner ear, supporting its role in normal ear development and function. In conclusion, our results suggest COL4A6 as being the fourth gene associated with X-linked nonsyndromic hearing loss. PMID:23714752

  7. Novel form of X-linked nonsyndromic hearing loss with cochlear malformation caused by a mutation in the type IV collagen gene COL4A6.

    PubMed

    Rost, Simone; Bach, Elisa; Neuner, Cordula; Nanda, Indrajit; Dysek, Sandra; Bittner, Reginald E; Keller, Alexander; Bartsch, Oliver; Mlynski, Robert; Haaf, Thomas; Müller, Clemens R; Kunstmann, Erdmute

    2014-02-01

    Hereditary hearing loss is the most common human sensorineural disorder. Genetic causes are highly heterogeneous, with mutations detected in >40 genes associated with nonsyndromic hearing loss, to date. Whereas autosomal recessive and autosomal dominant inheritance is prevalent, X-linked forms of nonsyndromic hearing impairment are extremely rare. Here, we present a Hungarian three-generation family with X-linked nonsyndromic congenital hearing loss and the underlying genetic defect. Next-generation sequencing and subsequent segregation analysis detected a missense mutation (c.1771G>A, p.Gly591Ser) in the type IV collagen gene COL4A6 in all affected family members. Bioinformatic analysis and expression studies support this substitution as being causative. COL4A6 encodes the alpha-6 chain of type IV collagen of basal membranes, which forms a heterotrimer with two alpha-5 chains encoded by COL4A5. Whereas mutations in COL4A5 and contiguous X-chromosomal deletions involving COL4A5 and COL4A6 are associated with X-linked Alport syndrome, a nephropathy associated with deafness and cataract, mutations in COL4A6 alone have not been related to any hereditary disease so far. Moreover, our index patient and other affected family members show normal renal and ocular function, which is not consistent with Alport syndrome, but with a nonsyndromic type of hearing loss. In situ hybridization and immunostaining demonstrated expression of the COL4A6 homologs in the otic vesicle of the zebrafish and in the murine inner ear, supporting its role in normal ear development and function. In conclusion, our results suggest COL4A6 as being the fourth gene associated with X-linked nonsyndromic hearing loss. PMID:23714752

  8. The study of pinch regimes based on radiation-enhanced compression and anomalous resistivity phenomena and their effects on hard x-ray emission in a Mather type dense plasma focus device (SABALAN2)

    NASA Astrophysics Data System (ADS)

    Piriaei, D.; Mahabadi, T. D.; Javadi, S.; Ghoranneviss, M.; Saw, S. H.; Lee, S.

    2015-12-01

    In this study, by using argon and nitrogen as the filling gases in a Mather type dense plasma focus device at different values of pressure and charging voltage, two different kinds of pinch regimes were observed for each of the gases. The physics of the pinch regimes could be explained by using the two versions of the Lee's computational model which predicted each of the scenarios and clarified their differences between the two gases according to the radiation-enhanced compression and, additionally, predicted the pinch regimes through the anomalous resistivity effect during the pinch time. This was accomplished through the fitting process (simulation) on the current signal. Moreover, the characteristic amplitude and time scales of the anomalous resistances were obtained. The correlations between the features of the plasma current dip and the emitted hard x-ray pulses were observed. The starting time, intensity, duration, and the multiple or single feature of the emitted hard x-ray strongly correlated to the same respective features of the current dip.

  9. The study of pinch regimes based on radiation-enhanced compression and anomalous resistivity phenomena and their effects on hard x-ray emission in a Mather type dense plasma focus device (SABALAN2)

    SciTech Connect

    Piriaei, D.; Javadi, S.; Ghoranneviss, M.; Mahabadi, T. D.; Saw, S. H.; Lee, S.

    2015-12-15

    In this study, by using argon and nitrogen as the filling gases in a Mather type dense plasma focus device at different values of pressure and charging voltage, two different kinds of pinch regimes were observed for each of the gases. The physics of the pinch regimes could be explained by using the two versions of the Lee's computational model which predicted each of the scenarios and clarified their differences between the two gases according to the radiation-enhanced compression and, additionally, predicted the pinch regimes through the anomalous resistivity effect during the pinch time. This was accomplished through the fitting process (simulation) on the current signal. Moreover, the characteristic amplitude and time scales of the anomalous resistances were obtained. The correlations between the features of the plasma current dip and the emitted hard x-ray pulses were observed. The starting time, intensity, duration, and the multiple or single feature of the emitted hard x-ray strongly correlated to the same respective features of the current dip.

  10. Analysis of the Type IV Fimbrial-Subunit Gene fimA of Xanthomonas hyacinthi: Application in PCR-Mediated Detection of Yellow Disease in Hyacinths

    PubMed Central

    van Doorn, J.; Hollinger, T. C.; Oudega, B.

    2001-01-01

    A sensitive and specific detection method was developed for Xanthomonas hyacinthi; this method was based on amplification of a subsequence of the type IV fimbrial-subunit gene fimA from strain S148. The fimA gene was amplified by PCR with degenerate DNA primers designed by using the N-terminal and C-terminal amino acid sequences of trypsin fragments of FimA. The nucleotide sequence of fimA was determined and compared with the nucleotide sequences coding for the fimbrial subunits in other type IV fimbria-producing bacteria, such as Xanthomonas campestris pv. vesicatoria, Neisseria gonorrhoeae, and Moraxella bovis. In a PCR internal primers JAAN and JARA, designed by using the nucleotide sequences of the variable central and C-terminal region of fimA, amplified a 226-bp DNA fragment in all X. hyacinthi isolates. This PCR was shown to be pathovar specific, as assessed by testing 71 Xanthomonas pathovars and bacterial isolates belonging to other genera, such as Erwinia and Pseudomonas. Southern hybridization experiments performed with the labelled 226-bp DNA amplicon as a probe suggested that there is only one structural type IV fimbrial-gene cluster in X. hyacinthi. Only two Xanthomonas translucens pathovars cross-reacted weakly in PCR. Primers amplifying a subsequence of the fimA gene of X. campestris pv. vesicatoria (T. Ojanen-Reuhs, N. Kalkkinen, B. Westerlund-Wikström, J. van Doorn, K. Haahtela, E.-L. Nurmiaho-Lassila, K. Wengelink, U. Bonas, and T. K. Korhonen, J. Bacteriol. 179: 1280–1290, 1997) were shown to be pathovar specific, indicating that the fimbrial-subunit sequences are more generally applicable in xanthomonads for detection purposes. Under laboratory conditions, approximately 1,000 CFU of X. hyacinthi per ml could be detected. In inoculated leaves of hyacinths the threshold was 5,000 CFU/ml. The results indicated that infected hyacinths with early symptoms could be successfully screened for X. hyacinthi with PCR. PMID:11157222

  11. Search for contact systems among EB-type binaries. IV - V375 Cas, UW Ori, DO Cas, RU ERI

    NASA Astrophysics Data System (ADS)

    Barone, F.; di Fiore, L.; Milano, L.; Pirozzi, L.; Russo, G.

    1992-12-01

    We present the analysis of the data of four EB-type eclipsing binaries, continuing our search for contact or almost contact systems. The Price algorithm has been used in conjunction to the Wilson-Devinney model to try to obtain, where possible, unambiguous solutions for all the systems.

  12. Welding IV.

    ERIC Educational Resources Information Center

    Allegheny County Community Coll., Pittsburgh, PA.

    Instructional objectives and performance requirements are outlined in this course guide for Welding IV, a competency-based course in advanced arc welding offered at the Community College of Allegheny County to provide students with proficiency in: (1) single vee groove welding using code specifications established by the American Welding Society…

  13. Anomalous gauge boson interactions

    SciTech Connect

    Aihara, H.; Barklow, T.; Baur, U. |

    1995-03-01

    We discuss the direct measurement of the trilinear vector boson couplings in present and future collider experiments. The major goals of such experiments will be the confirmation of the Standard Model (SM) predictions and the search for signals of new physics. We review our current theoretical understanding of anomalous trilinear gauge-boson self interactions. If the energy scale of the new physics is {approximately} 1 TeV, these low energy anomalous couplings are expected to be no larger than {Omicron}(10{sup {minus}2}). Constraints from high precision measurements at LEP and low energy charged and neutral current processes are critically reviewed.

  14. Abnormal type III collagen produced by an exon-17-skipping mutation of the COL3A1 gene in Ehlers-Danlos syndrome type IV is not incorporated into the extracellular matrix.

    PubMed Central

    Chiodo, A A; Sillence, D O; Cole, W G; Bateman, J F

    1995-01-01

    A novel heterozygous mutation of the COL3A1 gene that encodes the alpha 1(III) chains of type III collagen was identified in a family with the acrogeric form of Ehlers-Danlos syndrome type IV (EDS-IV). Cultured dermal fibroblasts produced normal and shortened alpha 1(III) chains. The triple helix of the latter chain was shortened owing to a 33 amino acid deletion of Gly-184 to Pro-216. The corresponding region of cDNA lacked 99 base pairs from nucleotides 1051 to 1149. The deletions corresponded exactly to the normal sequence encoded by exon 17 of the COL3A1 gene. The proband was heterozygous for a T to G transversion at position +2 of intron 17, which resulted in skipping of exon 17. The splicing defect was not corrected by growing the fibroblasts at 33 degrees C and no other splicing variants were identified at 33 or 37 degrees C. The affected brother had the same mutation but his unaffected mother did not. Heterotrimeric type III collagen molecules containing normal and mutant chains were retained within the cell. The mutant homotrimeric molecules were modified and secreted normally and were thermally stable. These normal characteristics of the mutant homotrimers suggested that the loss of ten Gly-Xaa-Yaa triplets (where Gly-Xaa-Yaa is a repetitive amino acid triplet structure in which Xaa and Yaa are other amino acids, proline and hydroxyproline being more common in the Yaa position) did not adversely affect the formation and stability of the triple helix or the structural requirements for secretion. However, the mutant homotrimers were not incorporated into the extracellular matrix of an in vitro model of EDS-IV dermis. The EDS-IV phenotype in this family was probably due to a deficiency in the amount of normal type III collagen available for formation of the heterotypic collagen fibrils of the extracellular matrix. Intracellular and extracellular quality-control mechanisms prevented the incorporation of heterotrimeric and homotrimeric mutant type III collagen

  15. A novel approach to the treatment of a direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV.

    PubMed

    Nakagawa, Ichiro; Park, Hun Soo; Wada, Takeshi; Takayama, Katsutoshi; Nakagawa, Hiroyuki; Kichikawa, Kimihiko; Nakase, Hiroyuki

    2016-01-01

    We report a case of a direct carotid-cavernous fistula (CCF) in a patient with Ehlers-Danlos syndrome type IV who presented with progressive chemosis and diplopia. To prevent potential lethal arterial wall injury due to the fragility of the arterial vessel wall, the ipsilateral carotid artery and internal jugular vein were surgically exposed for direct insertion of endovascular sheaths, and transvenous embolization was performed using triple microcatheters with detachable coils. The clinical course was uneventful, and chemosis and diplopia subsequently resolved. By the 6 month follow-up, MRI revealed no recurrence of the CCF. These techniques offer a unique access alternative for endovascular treatment, thereby reducing the risks associated with arterial dissection that often accompanies transfemoral access in this particular condition. PMID:25432980

  16. Type-IV Superconductivity Phenomenon: Cooper Pairs with Broken Parity and Spin-Rotational Symmetries in D- and S-wave Singlet Superconductors

    NASA Astrophysics Data System (ADS)

    Lebed, Andrei

    2006-03-01

    Paramagnetic effects are shown to result in the appearance of a triplet component of order parameter in vortex phases of d- and s-wave singlet superconductors in the absence of impurities. This component, which breaks both parity and spin-rotational symmetries of Cooper pairs, is expected to be of the order of unity in a number of modern superconductors such as high-Tc, organic, MgB2, and some others. A generic phase diagram of such type-IV superconductors [1], which are singlet ones at H=0 and in the Meissner phase and characterized by singlet-triplet mixed Copper pairs, δs+iδt, in a vortex phase, is suggested. [1] A.G. Lebed, Physical Review Letters, accepted (2006).

  17. Identification of novel short peptides derived from the {alpha}4, {alpha}5, and {alpha}6 fibrils of type IV collagen with anti-angiogenic properties

    SciTech Connect

    Karagiannis, Emmanouil D. . E-mail: ekaragi1@jhmi.edu; Popel, Aleksander S.

    2007-03-09

    Angiogenesis, or neovascularization, is tightly controlled by positive and negative regulators, many of which reside in the extracellular matrix. We have now identified eight novel 19- to 20-residue peptides derived from the {alpha}4, {alpha}5, and {alpha}6 fibrils of type IV collagen, which we have designated tetrastatins, pentastatins, and hexastatins, respectively. We have shown that these endogenous peptides suppress the proliferation and migration of HUVECs in vitro. By performing clustering analyses of the sequences using sequence similarity criteria and of the experimental results using a hierarchical algorithm, we report that the clusters identified by the experimental results coincide with the sequence-based clusters, indicating a tight relationship between peptide sequence and anti-angiogenic potency. These peptides may have potential as anti-angiogenic therapeutic agents.

  18. Steered molecular dynamics simulations of a bacterial type IV pilus reveal characteristics of an experimentally-observed, force-induced conformational transition

    NASA Astrophysics Data System (ADS)

    Baker, Joseph; Biais, Nicolas; Tama, Florence

    2011-10-01

    Type IV pili (T4P) are long, filamentous structures that emanate from the cellular surface of many infectious bacteria. They are built from a 158 amino acid long subunit called pilin. T4P can grow to many micrometers in length, and can withstand large tension forces. During the infection process, pili attach themselves to host cells, and therefore naturally find themselves under tension. We investigated the response of a T4 pilus to a pulling force using the method of steered molecular dynamics (SMD) simulation. Our simulations expose to the external environment an amino acid sequence initially hidden in the native filament, in agreement with experimental data. Therefore, our simulations might be probing the initial stage of the transition to a force-induced conformation of the T4 pilus. Additional exposed amino acid sequences that might be useful targets for drugs designed to mitigate bacterial infection were also predicted.

  19. De novo expression of a type IV collagen gene in Drosophila embryos is restricted to mesodermal derivatives and occurs at germ band shortening.

    PubMed

    Mirre, C; Cecchini, J P; Le Parco, Y; Knibiehler, B

    1988-02-01

    We have examined directly the expression of one collagen gene (DCg1) during Drosophila melanogaster embryogenesis by means of in situ hybridization. Transcripts of this gene, which were demonstrated to encode a basement membrane type IV collagen chain, began to accumulate specifically in mesodermal derivatives at stages 12-13 of embryogenesis, and not before. Cells expressing this gene overlap, or are closely intermingled with, somatic and visceral mesoderm in stages 12-14. In stages 15-17, in addition to the strongly positive fat bodies, highly labelled cell spots are found scattered around all the parts of the gut and symmetrically on each side of the ventral nerve cord. They correspond to circulating mesodermal cells which we consider to be haemocytes or mesoblasts. PMID:3138101

  20. A Component of the Xanthomonadaceae Type IV Secretion System Combines a VirB7 Motif with a N0 Domain Found in Outer Membrane Transport Proteins

    PubMed Central

    Souza, Diorge P.; Andrade, Maxuel O.; Alvarez-Martinez, Cristina E.; Arantes, Guilherme M.; Farah, Chuck S.; Salinas, Roberto K.

    2011-01-01

    Type IV secretion systems (T4SS) are used by Gram-negative bacteria to translocate protein and DNA substrates across the cell envelope and into target cells. Translocation across the outer membrane is achieved via a ringed tetradecameric outer membrane complex made up of a small VirB7 lipoprotein (normally 30 to 45 residues in the mature form) and the C-terminal domains of the VirB9 and VirB10 subunits. Several species from the genera of Xanthomonas phytopathogens possess an uncharacterized type IV secretion system with some distinguishing features, one of which is an unusually large VirB7 subunit (118 residues in the mature form). Here, we report the NMR and 1.0 Å X-ray structures of the VirB7 subunit from Xanthomonas citri subsp. citri (VirB7XAC2622) and its interaction with VirB9. NMR solution studies show that residues 27–41 of the disordered flexible N-terminal region of VirB7XAC2622 interact specifically with the VirB9 C-terminal domain, resulting in a significant reduction in the conformational freedom of both regions. VirB7XAC2622 has a unique C-terminal domain whose topology is strikingly similar to that of N0 domains found in proteins from different systems involved in transport across the bacterial outer membrane. We show that VirB7XAC2622 oligomerizes through interactions involving conserved residues in the N0 domain and residues 42–49 within the flexible N-terminal region and that these homotropic interactions can persist in the presence of heterotropic interactions with VirB9. Finally, we propose that VirB7XAC2622 oligomerization is compatible with the core complex structure in a manner such that the N0 domains form an extra layer on the perimeter of the tetradecameric ring. PMID:21589901

  1. YqfS from Bacillus subtilis Is a Spore Protein and a New Functional Member of the Type IV Apurinic/Apyrimidinic-Endonuclease Family

    PubMed Central

    Salas-Pacheco, José M.; Urtiz-Estrada, Norma; Martínez-Cadena, Guadalupe; Yasbin, Ronald E.; Pedraza-Reyes, Mario

    2003-01-01

    The enzymatic properties and the physiological function of the type IV apurinic/apyrimidinic (AP)-endonuclease homolog of Bacillus subtilis, encoded by yqfS, a gene specifically expressed in spores, were studied here. To this end, a recombinant YqfS protein containing an N-terminal His6 tag was synthesized in Escherichia coli and purified to homogeneity. An anti-His6-YqfS polyclonal antibody exclusively localized YqfS in cell extracts prepared from B. subtilis spores. The His6-YqfS protein demonstrated enzymatic properties characteristic of the type IV family of DNA repair enzymes, such as AP-endonucleases and 3′-phosphatases. However, the purified protein lacked both 5′-phosphatase and exonuclease III activities. YqfS showed not only a high level of amino acid identity with E. coli Nfo but also a high resistance to inactivation by EDTA, in the presence of DNA containing AP sites (AP-DNA). These results suggest that YqfS possesses a trinuclear Zn center in which the three metal atoms are intimately coordinated by nine conserved basic residues and two water molecules. Electrophoretic mobility shift assays demonstrated that YqfS possesses structural properties that permit it to bind and scan undamaged DNA as well as to strongly interact with AP-DNA. The ability of yqfS to genetically complement the DNA repair deficiency of an E. coli mutant lacking the major AP-endonucleases Nfo and exonuclease III strongly suggests that its product confers protection to cells against the deleterious effects of oxidative promoters and alkylating agents. Thus, we conclude that YqfS of B. subtilis is a spore-specific protein that has structural and enzymatic properties required to participate in the repair of AP sites and 3′ blocking groups of DNA generated during both spore dormancy and germination. PMID:12949090

  2. Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section.

    PubMed

    Bulusu, Kartik V; Plesniak, Michael W

    2016-01-01

    The arterial network in the human vasculature comprises of ubiquitously present blood vessels with complex geometries (branches, curvatures and tortuosity). Secondary flow structures are vortical flow patterns that occur in curved arteries due to the combined action of centrifugal forces, adverse pressure gradients and inflow characteristics. Such flow morphologies are greatly affected by pulsatility and multiple harmonics of physiological inflow conditions and vary greatly in size-strength-shape characteristics compared to non-physiological (steady and oscillatory) flows (1 - 7). Secondary flow structures may ultimately influence the wall shear stress and exposure time of blood-borne particles toward progression of atherosclerosis, restenosis, sensitization of platelets and thrombosis (4 - 6, 8 - 13). Therefore, the ability to detect and characterize these structures under laboratory-controlled conditions is precursor to further clinical investigations. A common surgical treatment to atherosclerosis is stent implantation, to open up stenosed arteries for unobstructed blood flow. But the concomitant flow perturbations due to stent installations result in multi-scale secondary flow morphologies (4 - 6). Progressively higher order complexities such as asymmetry and loss in coherence can be induced by ensuing stent failures vis-à-vis those under unperturbed flows (5). These stent failures have been classified as "Types I-to-IV" based on failure considerations and clinical severity (14). This study presents a protocol for the experimental investigation of the complex secondary flow structures due to complete transverse stent fracture and linear displacement of fractured parts ("Type IV") in a curved artery model. The experimental method involves the implementation of particle image velocimetry (2C-2D PIV) techniques with an archetypal carotid artery inflow waveform, a refractive index matched blood-analog working fluid for phase-averaged measurements (15 - 18

  3. Parental somatic and germ-line mosaicism for a multiexon deletion with unusual endpoints in a type III collagen (COL3A1) allele produces Ehlers-Danlos syndrome type IV in the heterozygous offspring.

    PubMed Central

    Milewicz, D M; Witz, A M; Smith, A C; Manchester, D K; Waldstein, G; Byers, P H

    1993-01-01

    Ehlers-Danlos syndrome (EDS) type IV is a dominantly inherited disorder that results from mutations in the type III collagen gene (COL3A1). We studied the structure of the COL3A1 gene of an individual with EDS type IV and that of her phenotypically normal parents. The proband was heterozygous for a 2-kb deletion in COL3A1, while her father was mosaic for the same deletion in somatic and germ cells. In fibroblasts from the father, approximately two-fifths of the COL3A1 alleles carried the deletion, but only 10% of the COL3A1 alleles in white blood cells were of the mutant species. The deletion in the mutant allele extended from intron 7 into intron 11. There was a 12-bp direct repeat in intron 7 and intron 11, the latter about 60 bp 5' to the junction. At the breakpoint there was a duplication of 10 bp from intron 11 separated by an insertion of 4 bp contained within the duplicated sequence. The father was mosaic for the deletion so that the gene rearrangement occurred during his early embryonic development prior to lineage allocation. These findings suggest that at least some of the deletions seen in human genes may occur during replication, rather than as a consequence of meiotic crossing-over, and that they thus have a risk for recurrence when observed de novo. Images Figure 1 Figure 2 Figure 3 PMID:8317500

  4. Parental somatic and germ-line mosaicism for a multiexon deletion with unusual endpoints in a type III collagen (COL3Al) allele produces ehlers-danlos syndrome type IV in the heterozygous offspring

    SciTech Connect

    McGookey Milewicz, D.; Witz, A.M.; Byers, P.H. ); Smith, A.C.M.; Manchester, D.K.; Waldstein, G. )

    1993-07-01

    Ehlers-Danlos syndrome (EDS) type IV is a dominantly inherited disorder that results from mutation in the type III collagen gene (COL3A1). The authors studied the structure of the COL3A1 gene of an individual with EDS type IV and that of her phenotypically normal parents. The proband was heterozygous for a 2-kb deletion in COL3A1, while her father was mosaic for the same deletion in somatic and germ cells. In fibroblasts from the father, approximately two-fifths of the COL3A1 alleles carried the deletion, but only 10% of the COL3A1 alleles in white blood cells were of the mutant species. The deletion in the mutant allele extended from intron 7 into intron 11. There was a 12-bp direct repeat in intron 7 and intron 11, the latter about 60 bp 5' to the junction. At the breakpoint there was a duplication of 10 bp from intron 11 separated by an insertion of 4 bp contained within the duplicated sequence. The father was mosaic for the deletion so that the gene rearrangement occurred during his early embryonic development prior to lineage allocation. These findings suggest that at least some of the deletions seen in human genes may occur during replication, rather than as a consequence of meiotic crossing-over, and that they thus have a risk for recurrence when observed de novo. 71 refs., 4 figs., 2 tabs.

  5. Syntheses, crystal structures, and properties of six new lanthanide(III) transition metal tellurium(IV) oxyhalides with three types of structures.

    PubMed

    Shen, Yue-Ling; Mao, Jiang-Gao

    2005-07-25

    Solid-state reactions of lanthanide(III) oxide (and lanthanide(III) oxyhalide), transition metal halide (and transition metal oxide), and TeO(2) at high temperature lead to six new lanthanide transition metal tellurium(IV) oxyhalides with three different types of structures, namely, DyCuTe(2)O(6)Cl, ErCuTe(2)O(6)Cl, ErCuTe(2)O(6)Br, Sm(2)Mn(Te(5)O(13))Cl(2), Dy(2)Cu(Te(5)O(13))Br(2), and Nd(4)Cu(TeO(3))(5)Cl(3). Compounds DyCuTe(2)O(6)Cl, ErCuTe(2)O(6)Cl, and ErCuTe(2)O(6)Br are isostructural. The lanthanide(III) ion is eight-coordinated by eight oxygen atoms, and the copper(II) ion is five-coordinated by four oxygens and a halide anion in a distorted square pyramidal geometry. The interconnection of Ln(III) and Cu(II) ions by bridging tellurite anions results in a three-dimensional (3D) network with tunnels along the a-axis; the halide anion and the lone-pair electrons of the tellurium(IV) ions are oriented toward the cavities of the tunnels. Compounds Sm(2)Mn(Te(5)O(13))Cl(2) and Dy(2)Cu(Te(5)O(13))Br(2) are isostructural. The lanthanide(III) ions are eight-coordinated by eight oxygens, and the divalent transition metal ion is octahedrally coordinated by six oxygens. Two types of polymeric tellurium(IV) oxide anions are formed: Te(3)O(8)(4)(-) and Te(4)O(10)(4)(-). The interconnection of the lanthanide(III) and divalent transition metal ions by the above two types of polymeric tellurium(IV) oxide anions leads to a 3D network with long, narrow-shaped tunnels along the b-axis. The halide anions remain isolated and are located at the above tunnels. Nd(4)Cu(TeO(3))(5)Cl(3) features a different structure. All five of the Nd(III) ions are eight-coordinated (NdO(8) for Nd(1), Nd(2), Nd(4), and Nd(5) and NdO(7)Cl for Nd(3)), and the copper(I) ion is tetrahedrally coordinated by four chloride anions. The interconnection of Nd(III) ions by bridging tellurite anions resulted in a 3D network with large tunnels along the b-axis. The CuCl(4) tetrahedra are interconnected into

  6. Chemical and physical studies of type 3 chondrites. IV Annealing studies of a type 3.4 ordinary chondrite and the metamorphic history of meteorites

    NASA Astrophysics Data System (ADS)

    Guimon, R. K.; Keck, B. D.; Weeks, K. S.; Dehart, J.; Sears, D. W. G.

    1985-07-01

    Samples of a type 3.4 chondrite have been annealed at 400 - 1000°C for 1 - 200 hours, their thermoluminescence properties determined and analyzed for K, Na, Mn, Sc and Ca by instrumental neutron activation analysis.

  7. Continued ultraviolet studies of some Be stars of later type

    NASA Technical Reports Server (NTRS)

    Slettebak, A.

    1985-01-01

    Anomalous ionization (C IV and Si IV) is seen in IUE spectra of Be stars as late as B8, and occurs also in standard stars of similar spectral type. Asymmetrical lines suggesting mass loss are present in all the Be stars and several of the standard stars as well, with no obvious correlation with v sin i. Emission shoulders are present in the Mg II lines of two B5e stars but not in Be stars of later type. Again there is no correlation with v sin i. The A-F shell stars show rich Fe II absorption spectra in the ultraviolet, in one case with velocity structure.

  8. IVS Organization

    NASA Technical Reports Server (NTRS)

    2004-01-01

    International VLBI Service (IVS) is an international collaboration of organizations which operate or support Very Long Baseline Interferometry (VLBI) components. The goals are: To provide a service to support geodetic, geophysical and astrometric research and operational activities. To promote research and development activities in all aspects of the geodetic and astrometric VLBI technique. To interact with the community of users of VLBI products and to integrate VLBI into a global Earth observing system.

  9. TraK and TraB are conserved outer membrane proteins of the Neisseria gonorrhoeae Type IV secretion system and are expressed at low levels in wild-type cells.

    PubMed

    Ramsey, Meghan E; Hackett, Kathleen T; Bender, Tobias; Kotha, Chaitra; van der Does, Chris; Dillard, Joseph P

    2014-08-15

    Neisseria gonorrhoeae uses a type IV secretion system (T4SS) to secrete chromosomal DNA into the medium, and this DNA is effective in transforming other gonococci via natural transformation. In addition, the T4SS is important in the initial stages of biofilm development and mediates intracellular iron uptake in the absence of TonB. To better understand the mechanism of type IV secretion in N. gonorrhoeae, we examined the expression levels and localization of two predicted T4SS outer membrane proteins, TraK and TraB, in the wild-type strain as well as in overexpression strains and in a strain lacking all of the T4SS proteins. Despite very low sequence similarity to known homologues, TraB (VirB10 homolog) and TraK (VirB9 homolog) localized similarly to related proteins in other systems. Additionally, we found that TraV (a VirB7 homolog) interacts with TraK, as in other T4SSs. However, unlike in other systems, neither TraK nor TraB required the presence of other T4SS components for proper localization. Unlike other gonococcal T4SS proteins we have investigated, protein levels of the outer membrane proteins TraK and TraB were extremely low in wild-type cells and were undetectable by Western blotting unless overexpressed or tagged with a FLAG3 triple-epitope tag. Localization of TraK-FLAG3 in otherwise wild-type cells using immunogold electron microscopy of thin sections revealed a single gold particle on some cells. These results suggest that the gonococcal T4SS may be present in single copy per cell and that small amounts of T4SS proteins TraK and TraB are sufficient for DNA secretion. PMID:24914183

  10. TraK and TraB Are Conserved Outer Membrane Proteins of the Neisseria gonorrhoeae Type IV Secretion System and Are Expressed at Low Levels in Wild-Type Cells

    PubMed Central

    Ramsey, Meghan E.; Hackett, Kathleen T.; Bender, Tobias; Kotha, Chaitra; van der Does, Chris

    2014-01-01

    Neisseria gonorrhoeae uses a type IV secretion system (T4SS) to secrete chromosomal DNA into the medium, and this DNA is effective in transforming other gonococci via natural transformation. In addition, the T4SS is important in the initial stages of biofilm development and mediates intracellular iron uptake in the absence of TonB. To better understand the mechanism of type IV secretion in N. gonorrhoeae, we examined the expression levels and localization of two predicted T4SS outer membrane proteins, TraK and TraB, in the wild-type strain as well as in overexpression strains and in a strain lacking all of the T4SS proteins. Despite very low sequence similarity to known homologues, TraB (VirB10 homolog) and TraK (VirB9 homolog) localized similarly to related proteins in other systems. Additionally, we found that TraV (a VirB7 homolog) interacts with TraK, as in other T4SSs. However, unlike in other systems, neither TraK nor TraB required the presence of other T4SS components for proper localization. Unlike other gonococcal T4SS proteins we have investigated, protein levels of the outer membrane proteins TraK and TraB were extremely low in wild-type cells and were undetectable by Western blotting unless overexpressed or tagged with a FLAG3 triple-epitope tag. Localization of TraK-FLAG3 in otherwise wild-type cells using immunogold electron microscopy of thin sections revealed a single gold particle on some cells. These results suggest that the gonococcal T4SS may be present in single copy per cell and that small amounts of T4SS proteins TraK and TraB are sufficient for DNA secretion. PMID:24914183

  11. A comprehensive survey of the laminins and collagens type IV expressed in mouse Leydig cells and their regulation by LH/hCG.

    PubMed

    Mazaud Guittot, Séverine; Vérot, Adélie; Odet, Fanny; Chauvin, Marie-Agnès; le Magueresse-Battistoni, Brigitte

    2008-04-01

    Extracellular matrix (ECM) proteins have been shown to alter Leydig cell steroidogenesis in vitro, substantiating the hypothesis that Leydig cell steroidogenic activity and matrix environment are interdependent events. However, the nature of the ECM components synthesized by Leydig cells and their regulation by LH/human chorionic gonadotropin (hCG) remain unknown. Here, we examine the occurrence of the 11 laminin subunits and the 6 alpha chains of collagen IV (COL4A1-6) by RT-PCR in Leydig cells cultured with or without LH/hCG. Leydig cells were a tumor Leydig cell line (mLTC-1) or 8-week-old mice Leydig cells. Based on PCR data, it is suggested that normal Leydig cells may synthesize a maximum of 11 laminin heterotrimers and the 6 alpha chains of collagen IV. They also may synthesize various proteases and inhibitors of the metzincin family. The mLTC-1 cells have a limited repertoire as compared with normal Leydig cells. Interestingly, none of the ten proteases and inhibitors monitored is under LH-hCG regulation whereas every protease and inhibitor of the serine protease family yet identified in Leydig cells is under gonadotropin regulation. In addition, a few laminin and collagen subunit genes are regulated by LH/hCG. These are laminins alpha3 and gamma3 (Lama3 and Lamc3), Col4a3, and Col4a6, which are negatively regulated by LH/hCG in both Leydig cell types, and Col4a4, which was downregulated in primary cultures but not in mLTC-1 cells. Collectively, the present study suggests that Leydig cells modulate in a selective fashion their matrix environment in response to their trophic hormone. This may alter the steroidogenic outcome of Leydig cells. PMID:18367508

  12. Strong association between a splice mutation (IVS12+5G{r_arrow}A) and haplotype 6 in hereditary tyrosinemia type I

    SciTech Connect

    Tanguay, R.M.; St-Louis, M.; Gibson, K.

    1994-09-01

    Hereditary tyrosinemia type I (HT I; McKusick 276700) is a severe inborn error of tyrosine catabolism pathway caused by a deficiency of fumarylacetoacetate hydrolase (FAH). The highest frequency reported is the one in Saguenay-Lac St-Jean (Quebec, Canada) where 1:1,846 births are affected. The FAH gene has been cloned and several mutations have been described. Allele specific oligonucleotide (ASO) hybridization was used to examine the frequency of a splice (IVS12-5G{r_arrow}A) mutation recently reported and RFLP analysis was done to identify haplotypes related to HT I. The splice mutation was found on 45/50 alleles (90%) in patients from SLSJ and 12/66 (18%) alleles from patients world-wide. All 25 patients from the SLSJ region were positive with 20 being homozygous, indicating that this mutation is the major cause of HT I in French Canada. Of these 25 patients, 96% were positive for one haplotype called no 6 which is these 25 patients, 96% were positive for one haplotype called no 6 which is identified by TaqI, RsaI, BglII, MspI and KpnI digestions. These data show a really strong association between the mutation (IVS12+5G{r_arrow}A) and haplotype 6. Among our patients from around the world, {approximately}52% were positive for haplotype 6 indicating its strong relation with HT I. These results provide the rationale for DNA-based carrier testing for HT I in the F-C population at risk as well as in HT I patients in general.

  13. Chemical Genetics Reveals Bacterial and Host Cell Functions Critical for Type IV Effector Translocation by Legionella pneumophila

    PubMed Central

    Charpentier, Xavier; Gabay, Joëlle E.; Reyes, Moraima; Zhu, Jing W.; Weiss, Arthur; Shuman, Howard A.

    2009-01-01

    Delivery of effector proteins is a process widely used by bacterial pathogens to subvert host cell functions and cause disease. Effector delivery is achieved by elaborate injection devices and can often be triggered by environmental stimuli. However, effector export by the L. pneumophila Icm/Dot Type IVB secretion system cannot be detected until the bacterium encounters a target host cell. We used chemical genetics, a perturbation strategy that utilizes small molecule inhibitors, to determine the mechanisms critical for L. pneumophila Icm/Dot activity. From a collection of more than 2,500 annotated molecules we identified specific inhibitors of effector translocation. We found that L. pneumophila effector translocation in macrophages requires host cell factors known to be involved in phagocytosis such as phosphoinositide 3-kinases, actin and tubulin. Moreover, we found that L. pneumophila phagocytosis and effector translocation also specifically require the receptor protein tyrosine phosphate phosphatases CD45 and CD148. We further show that phagocytosis is required to trigger effector delivery unless intimate contact between the bacteria and the host is artificially generated. In addition, real-time analysis of effector translocation suggests that effector export is rate-limited by phagocytosis. We propose a model in which L. pneumophila utilizes phagocytosis to initiate an intimate contact event required for the translocation of pre-synthesized effector molecules. We discuss the need for host cell participation in the initial step of the infection and its implications in the L. pneumophila lifestyle. Chemical genetic screening provides a novel approach to probe the host cell functions and factors involved in host–pathogen interactions. PMID:19578436

  14. Identification of Coxiella burnetii Type IV Secretion Substrates Required for Intracellular Replication and Coxiella-Containing Vacuole Formation

    PubMed Central

    Weber, Mary M.; Chen, Chen; Rowin, Kristina; Mertens, Katja; Galvan, Gloria; Zhi, Hui; Dealing, Christopher M.; Roman, Victor A.; Banga, Simran; Tan, Yunhao; Luo, Zhao-Qing

    2013-01-01

    Coxiella burnetii, the etiological agent of acute and chronic Q fever in humans, is a naturally intracellular pathogen that directs the formation of an acidic Coxiella-containing vacuole (CCV) derived from the host lysosomal network. Central to its pathogenesis is a specialized type IVB secretion system (T4SS) that delivers effectors essential for intracellular replication and CCV formation. Using a bioinformatics-guided approach, 234 T4SS candidate substrates were identified. Expression of each candidate as a TEM-1 β-lactamase fusion protein led to the identification of 53 substrates that were translocated in a Dot/Icm-dependent manner. Ectopic expression in HeLa cells revealed that these substrates trafficked to distinct subcellular sites, including the endoplasmic reticulum, mitochondrion, and nucleus. Expression in Saccharomyces cerevisiae identified several substrates that were capable of interfering with yeast growth, suggesting that these substrates target crucial host processes. To determine if any of these T4SS substrates are necessary for intracellular replication, we isolated 20 clonal T4SS substrate mutants using the Himar1 transposon and transposase. Among these, 10 mutants exhibited defects in intracellular growth and CCV formation in HeLa and J774A.1 cells but displayed normal growth in bacteriological medium. Collectively, these results indicate that C. burnetii encodes a large repertoire of T4SS substrates that play integral roles in host cell subversion and CCV formation and suggest less redundancy in effector function than has been found in the comparative Legionella Dot/Icm model. PMID:23813730

  15. Colored models for anomalous nuclei

    SciTech Connect

    Watson, P.J.S.; Saly, R.; Romo, W.J.; Sundaresan, M.K.; Campbell, B.; Elias, V.

    1983-04-01

    There seems to be good experimental evidence that anomalous nuclei are produced in heavy-ion collisions; they are anomalous in that they have an abnormally short mean free path, for example, in nuclear emulsions. Here we consider the possibility that anomalous nuclei are combinations of a colored anomalous particle fragment (based on theories with spontaneous breakdown of color symmetry) with ordinary nucleons. Phenomenological implications of various possible models in which the anomalous particle fragment is considered to be a colored particle with the color symmetry SU(3)/sub c/ explicitly broken are given.

  16. Distinct docking and stabilization steps of the pseudopilus conformational transition path suggest rotational assembly of type IV pilus-like fibers

    PubMed Central

    Nivaskumar, Mangayarkarasi; Bouvier, Guillaume; Campos, Manuel; Nadeau, Nathalie; Yu, Xiong; Egelman, Edward H.; Nilges, Michael; Francetic, Olivera

    2014-01-01

    SUMMARY The closely related bacterial type II secretion (T2S) and type IV pilus (T4P) systems are sophisticated machines that assemble dynamic fibers promoting protein transport, motility or adhesion. Despite their essential role in virulence, the molecular mechanisms underlying helical fiber assembly remain unknown. Here we use electron microscopy and flexible modeling to study conformational changes of PulG pili assembled by the Klebsiella oxytoca T2SS. Neural network analysis of 3900 pilus models suggested a transition path towards low-energy conformations driven by progressive increase in fiber helical twist. Detailed predictions of inter-protomer contacts along this path were tested by site-directed mutagenesis, pilus assembly and protein secretion analyses. We demonstrate that electrostatic interactions between adjacent protomers (P-P+1) in the membrane drive pseudopilin docking, while P-P+3 and P-P+4 contacts determine downstream fiber stabilization steps. These results support a new model of a spool-like assembly mechanism for fibers of the T2SS-T4P superfamily. PMID:24685147

  17. Distinct docking and stabilization steps of the Pseudopilus conformational transition path suggest rotational assembly of type IV pilus-like fibers.

    PubMed

    Nivaskumar, Mangayarkarasi; Bouvier, Guillaume; Campos, Manuel; Nadeau, Nathalie; Yu, Xiong; Egelman, Edward H; Nilges, Michael; Francetic, Olivera

    2014-05-01

    The closely related bacterial type II secretion (T2S) and type IV pilus (T4P) systems are sophisticated machines that assemble dynamic fibers promoting protein transport, motility, or adhesion. Despite their essential role in virulence, the molecular mechanisms underlying helical fiber assembly remain unknown. Here, we use electron microscopy and flexible modeling to study conformational changes of PulG pili assembled by the Klebsiella oxytoca T2SS. Neural network analysis of 3,900 pilus models suggested a transition path toward low-energy conformations driven by progressive increase in fiber helical twist. Detailed predictions of interprotomer contacts along this path were tested by site-directed mutagenesis, pilus assembly, and protein secretion analyses. We demonstrate that electrostatic interactions between adjacent protomers (P-P+1) in the membrane drive pseudopilin docking, while P-P+3 and P-P+4 contacts determine downstream fiber stabilization steps. These results support a model of a spool-like assembly mechanism for fibers of the T2SS-T4P superfamily. PMID:24685147

  18. A case of subepidermal blistering disease with autoantibodies to multiple laminin subunits who developed later autoantibodies to alpha-5 chain of type IV collagen associated with membranous glomerulonephropathy.

    PubMed

    Sueki, Hirohiko; Sato, Yoshinori; Ohtoshi, Shinpei; Nakada, Tokio; Yoshimura, Ashio; Tateishi, Chiharu; Borza, Dorin-Bogdan; Fader, William; Ghohestani, Reza F; Hirako, Yoshiaki; Koga, Hiroshi; Ishii, Norito; Tsuchisaka, Atsunari; Qian, Hua; Li, Xiaoguang; Hashimoto, Takashi

    2015-09-01

    We report a 68-year-old Japanese female patient with subepidermal blistering disease with autoantibodies to multiple laminins, who subsequently developed membranous glomerulonephropathy. At skin disease stage, immunofluorescence demonstrated IgG anti-basement membrane zone antibodies reactive with dermal side of NaCl-split skin. Immunoblotting of human dermal extract, purified laminin-332, hemidesmosome-rich fraction and laminin-521 trimer recombinant protein (RP) detected laminin γ-1 and α-3 and γ-2 subunits of laminin-332. Three years after skin lesions disappeared, nephrotic symptoms developed. Antibodies to α-3 chain of type IV collagen (COL4A3) were negative, thus excluding the diagnosis of Goodpasture syndrome. All anti-laminin antibodies disappeared. Additional IB and ELISA studies of RPs of various COL4 chains revealed reactivity with COL4A5, but not with COL4A6 or COL4A3. Although diagnosis of anti-laminin γ-1 (p200) pemphigoid or anti-laminin-332-type mucous membrane pemphigoid could not be made, this case was similar to previous cases with autoantibodies to COL4A5 and/or COL4A6. PMID:25633161

  19. Simultaneous Near-Sun Observations of a Moving Type IV Radio Burst and the Associated White-Light Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Hariharan, K.; Ramesh, R.; Kathiravan, C.; Wang, T. J.

    2016-06-01

    We present rare contemporaneous low-frequency ( < 100 MHz) imaging, spectral, and polarimetric observations of a moving type IV radio burst that had close spatio-temporal association with a white-light coronal mass ejection (CME) near the Sun. We estimate the electron density near the burst region from white-light coronagraph polarized brightness (pB) images of the CME as well as the two-dimensional radio imaging observations of the thermal free-free emission at a typical radio frequency such as 80 MHz. We analyze the burst properties such as the degree of circular polarization, the spectral index, and fine structures using the radio polarimeter and the radio spectral observations. The obtained results suggest that second harmonic plasma emission from the enhanced electron density in the leading edge of the CME is the cause of the radio burst. We determine the strength of the coronal magnetic field ( B) for the first time based on this interpretation. The estimated value ( B ≈ 1 gauss) in the CME leading edge at a heliocentric distance of ≈ 2.2 R_{⊙ } agrees well with the similar B values reported earlier based on other types of observations.

  20. Studying Coxiella burnetii Type IV Substrates in the Yeast Saccharomyces cerevisiae: Focus on Subcellular Localization and Protein Aggregation

    PubMed Central

    Rodríguez-Escudero, María; Cid, Víctor J.; Molina, María; Schulze-Luehrmann, Jan; Lührmann, Anja; Rodríguez-Escudero, Isabel

    2016-01-01

    Coxiella burnetii is a Gram-negative obligate parasitic bacterium that causes the disease Q-fever in humans. To establish its intracellular niche, it utilizes the Icm/Dot type IVB secretion system (T4BSS) to inject protein effectors into the host cell cytoplasm. The host targets of most cognate and candidate T4BSS-translocated effectors remain obscure. We used the yeast Saccharomyces cerevisiae as a model to express and study six C. burnetii effectors, namely AnkA, AnkB, AnkF, CBU0077, CaeA and CaeB, in search for clues about their role in C. burnetii virulence. When ectopically expressed in HeLa cells, these effectors displayed distinct subcellular localizations. Accordingly, GFP fusions of these proteins produced in yeast also decorated distinct compartments, and most of them altered cell growth. CaeA was ubiquitinated both in yeast and mammalian cells and, in S. cerevisiae, accumulated at juxtanuclear quality-control compartments (JUNQs) and insoluble protein deposits (IPODs), characteristic of aggregative or misfolded proteins. AnkA, which was not ubiquitinated, accumulated exclusively at the IPOD. CaeA, but not AnkA or the other effectors, caused oxidative damage in yeast. We discuss that CaeA and AnkA behavior in yeast may rather reflect misfolding than recognition of conserved targets in the heterologous system. In contrast, CBU0077 accumulated at vacuolar membranes and abnormal ER extensions, suggesting that it interferes with vesicular traffic, whereas AnkB associated with the yeast nucleolus. Both effectors shared common localization features in HeLa and yeast cells. Our results support the idea that C. burnetii T4BSS effectors manipulate multiple host cell targets, which can be conserved in higher and lower eukaryotic cells. However, the behavior of CaeA and AnkA prompt us to conclude that heterologous protein aggregation and proteostatic stress can be a limitation to be considered when using the yeast model to assess the function of bacterial effectors

  1. Ehlers-Danlos Syndrome type IV: a multi-exon deletion in one of the two COL3A1 alleles affecting structure, stability, and processing of type III procollagen

    SciTech Connect

    Superti-Furga, A.; Gugler, E.; Gitzelmann, R.; Steinmann, B.

    1988-05-05

    The authors have studied a patient with severe, dominantly inherited Ehlers-Danlos syndrome type IV. The results indicate that this patient carries a deletion of 3.3 kilobase pairs in the triple helical coding domain of one of the two alleles for the pro-..cap alpha..-chains of type III collagen (COL3A1). His cultured skin fibroblasts contain equal amounts of normal length mRNA and of mRNA shortened by approximately 600 bases, and synthesize both normal and shortened pro-..cap alpha..1(III)-chains. In procollagen molecules containing one or more shortened chains, a triple helix is formed with a length of only about 780 amino acids. The mutant procollagen molecules have decreased thermal stability, are less efficiently secreted, and are not processed as their normal counterpart. The deletion in this family is the first mutation to be described in COL3A1.

  2. Anomalous Oxide Charge Variation Identified by Alternating Current Surface Photovoltage Method in Cr-Aqueous-Solution-Rinsed p-Type Si(001) Wafers Exposed to Air

    NASA Astrophysics Data System (ADS)

    Shimizu, Hirofumi; Sanada, Yuji

    2011-11-01

    Chromium (Cr)-aqueous-solution-rinsed and/or hydrofluoric acid (HF)-solution-dipped p-type silicon (Si) (001) wafer surfaces are investigated by the frequency-dependent alternating current (AC) surface photovoltage (SPV) method. At the Cr(OH)3/p-type Si interface, in principle, a Schottky barrier could not possibly be generated. The Cr ion (Cr3+) is considered to forcibly deprive a p-type Si substrate of electrons during metallization (Cr3++3e-→Cr). Thus, at an early stage of air exposure, a positive fixed oxide charge may be compensated for by electrons, indicating the disappearance of AC SPV. With air exposure time, AC SPV emerges again and increases gradually in a Cr-deposited p-type Si(001) surface. This is because the native oxide between the Cr atom layer and the p-type Si substrate grows with time. As a result, a positive fixed oxide charge exceeds the overall charge state of the Cr-deposited p-type Si surface. Thus, AC SPV appears again and gradually increases with the fixed oxide charge in p-type Si. The saturated value is in a good agreement with that of the HF aqueous-solution-dipped p-type Si surface.

  3. Nonlocal Anomalous Hall Effect

    NASA Astrophysics Data System (ADS)

    Zhang, Steven S.-L.; Vignale, Giovanni

    2016-04-01

    The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.

  4. The S(IV)-type Asteroids as Ordinary Chondrite Parent Body Candidates: Implications for the Completeness of the Meteorite Sample of Asteroids

    NASA Astrophysics Data System (ADS)

    Gaffey, M. J.

    1995-09-01

    The discrepancy between the abundance of ordinary chondrites (OCs) among the meteorites and the rarity of unambiguously similar assemblages in the asteroid belt has been a major point of discussion within and between the asteroid and meteorite communities. Various resolutions to this apparent paradox have been proposed [e.g., 1-5], including: 1) interpretations of S-type asteroid spectra are incorrect due to space weathering effects; 2) ordinary chondrites derive from a few rare but favorably situated parent bodies; 3) OCs come from a residual population of small unheated mainbelt asteroids; 4) shock effects darken OC parent body surfaces disguising them as C-type asteroids, and 5) OCs come from inner solar system planetesimals ejected to the Oort cloud which have been recently perturbed into Earth-crossing orbits. Although none of these possibilities has yet been rigorously excluded, recent investigations suggest that the resolution of the apparent paradox lies in some combination of the first three options. For option 3, the discovery of a small mainbelt asteroid with an OC-like spectrum indicates OC-assemblages among the smaller mainbelt asteroids [6], although their abundance is still low in the current sample [7]. For option 2, the mineralogical survey indicated that while most S-asteroids could be rigorously excluded on mineralogical criteria, the S(IV) subtype of this class has silicate compositions within the OC range [8]. The S(IV)-objects are concentrated near the 3:1 secular resonance at 2.5 AU providing an efficient escape into Earth-crossing orbits. Unfortunately for a simple resolution of the OC parent body question, S(IV) spectra still exhibit weaker silicate features and redder spectral slopes than OC assemblages. Although significant uncertainties remain, optical alteration of asteroid surfaces interpreted from the Galileo images of Ida and Gaspra may reconcile the mismatch between OC and S(IV) spectra [option 1]. Although only a subset of the S(IV

  5. TgaA, a VirB1-Like Component Belonging to a Putative Type IV Secretion System of Bifidobacterium bifidum MIMBb75

    PubMed Central

    Balzaretti, Silvia; Taverniti, Valentina; Miriani, Matteo; Milani, Christian; Scarafoni, Alessio; Corona, Silvia; Ciranna, Alessandro; Arioli, Stefania; Santala, Ville; Iametti, Stefania; Bonomi, Francesco; Ventura, Marco; Mora, Diego; Karp, Matti

    2014-01-01

    Bifidobacterium bifidum MIMBb75 is a human intestinal isolate demonstrated to be interactive with the host and efficacious as a probiotic. However, the molecular biology of this microorganism is yet largely unknown. For this reason, we undertook whole-genome sequencing of B. bifidum MIMBb75 to identify potential genetic factors that would explain the metabolic and probiotic attributes of this bacterium. Comparative genomic analysis revealed a 45-kb chromosomal region that comprises 19 putative genes coding for a potential type IV secretion system (T4SS). Thus, we undertook the initial characterization of this genetic region by studying the putative virB1-like gene, named tgaA. Gene tgaA encodes a peptidoglycan lytic enzyme containing two active domains: lytic murein transglycosylase (LT, cd00254.3) and cysteine- and histidine-dependent amidohydrolase/peptidase (CHAP, pfam05257.4). By means of several in vitro assays, we experimentally confirmed that protein TgaA, consistent with its computationally assigned role, has peptidoglycan lytic activity, which is principally associated to the LT domain. Furthermore, immunofluorescence and immunogold labeling showed that the protein TgaA is abundantly expressed on the cell surface of B. bifidum MIMBb75. According to the literature, the T4SSs, which have not been characterized before in bifidobacteria, can have important implications for bacterial cell-to-cell communication as well as cross talk with host cells, justifying the interest for further studies aimed at the investigation of this genetic region. PMID:24951779

  6. Evidence of the Presence of a Functional Dot/Icm Type IV-B Secretion System in the Fish Bacterial Pathogen Piscirickettsia salmonis

    PubMed Central

    Gómez, Fernando A.; Tobar, Jaime A.; Henríquez, Vitalia; Sola, Mariel; Altamirano, Claudia; Marshall, Sergio H.

    2013-01-01

    Piscirickettsia salmonis is a fish bacterial pathogen that has severely challenged the sustainability of the Chilean salmon industry since its appearance in 1989. As this Gram-negative bacterium has been poorly characterized, relevant aspects of its life cycle, virulence and pathogenesis must be identified in order to properly design prophylactic procedures. This report provides evidence of the functional presence in P. salmonis of four genes homologous to those described for Dot/Icm Type IV Secretion Systems. The Dot/Icm System, the major virulence mechanism of phylogenetically related pathogens Legionella pneumophila and Coxiella burnetii, is responsible for their intracellular survival and multiplication, conditions that may also apply to P. salmonis. Our results demonstrate that the four P. salmonis dot/icm homologues (dotB, dotA, icmK and icmE) are expressed both during in vitro tissue culture cells infection and growing in cell-free media, suggestive of their putative constitutive expression. Additionally, as it happens in other referential bacterial systems, temporal acidification of cell-free media results in over expression of all four P. salmonis genes, a well-known strategy by which SSTIV-containing bacteria inhibit phagosome-lysosome fusion to survive. These findings are very important to understand the virulence mechanisms of P. salmonis in order to design new prophylactic alternatives to control the disease. PMID:23383004

  7. Type IV Pili in Francisella tularensis: Roles of pilF and pilT in Fiber Assembly, Host Cell Adherence, and Virulence ▿

    PubMed Central

    Chakraborty, Subhra; Monfett, Michael; Maier, Tamara M.; Benach, Jorge L.; Frank, Dara W.; Thanassi, David G.

    2008-01-01

    Francisella tularensis, a highly virulent facultative intracellular bacterium, is the causative agent of tularemia. Genome sequencing of all F. tularensis subspecies revealed the presence of genes that could encode type IV pili (Tfp). The live vaccine strain (LVS) expresses surface fibers resembling Tfp, but it was not established whether these fibers were indeed Tfp encoded by the pil genes. We show here that deletion of the pilF putative Tfp assembly ATPase in the LVS resulted in a complete loss of surface fibers. Disruption of the pilT putative disassembly ATPase also caused a complete loss of pili, indicating that pilT functions differently in F. tularensis than in model Tfp systems such as those found in Pseudomonas aeruginosa and Neisseria spp. The LVS pilF and pilT mutants were attenuated for virulence in a mouse model of tularemia by the intradermal route. Furthermore, although absence of pili had no effect on the ability of the LVS to replicate intracellularly, the pilF and pilT mutants were defective for adherence to macrophages, pneumocytes, and hepatocytes. This work confirms that the surface fibers expressed by the LVS are encoded by the pil genes and provides evidence that the Francisella pili contribute to host cell adhesion and virulence. PMID:18426883

  8. Characterization of BseMII, a new type IV restriction–modification system, which recognizes the pentanucleotide sequence 5′-CTCAG(N)10/8↓

    PubMed Central

    Jurenaite-Urbanaviciene, Sonata; Kazlauskiene, Ruta; Urbelyte, Virginija; Maneliene, Zita; Petruyte, Maryte; Lubys, Arvydas; Janulaitis, Arvydas

    2001-01-01

    We report the properties of the new BseMII restriction and modification enzymes from Bacillus stearothermophilus Isl 15-111, which recognize the 5′-CTCAG sequence, and the nucleotide sequence of the genes encoding them. The restriction endonuclease R.BseMII makes a staggered cut at the tenth base pair downstream of the recognition sequence on the upper strand, producing a two base 3′-protruding end. Magnesium ions and S-adenosyl-l-methionine (AdoMet) are required for cleavage. S-adenosylhomocysteine and sinefungin can replace AdoMet in the cleavage reaction. The BseMII methyltransferase modifies unique adenine residues in both strands of the target sequence 5′-CTCAG-3′/5′-CTGAG-3′. Monomeric R.BseMII in addition to endonucleolytic activity also possesses methyltransferase activity that modifies the A base only within the 5′-CTCAG strand of the target duplex. The deduced amino acid sequence of the restriction endonuclease contains conserved motifs of DNA N6-adenine methylases involved in S-adenosyl-l-methionine binding and catalysis. According to its structure and enzymatic properties, R.BseMII may be regarded as a representative of the type IV restriction endonucleases. PMID:11160921

  9. PilF Is an Outer Membrane Lipoprotein Required for Multimerization and Localization of the Pseudomonas aeruginosa Type IV Pilus Secretin

    SciTech Connect

    Koo, J.; Tammam, S; Ku, S; Samplaeanu, L; Burrows, L; Howell, P

    2008-01-01

    Type IV pili (T4P) are retractile appendages that contribute to the virulence of bacterial pathogens. PilF is a Pseudomonas aeruginosa lipoprotein that is essential for T4P biogenesis. Phenotypic characterization of a pilF mutant confirmed that T4P-mediated functions are abrogated: T4P were no longer present on the cell surface, twitching motility was abolished, and the mutant was resistant to infection by T4P retraction-dependent bacteriophage. The results of cellular fractionation studies indicated that PilF is the outer membrane pilotin required for the localization and multimerization of the secretin, PilQ. Mutation of the putative PilF lipidation site untethered the protein from the outer membrane, causing secretin assembly in both inner and outer membranes. T4P-mediated twitching motility and bacteriophage susceptibility were moderately decreased in the lipidation site mutant, while cell surface piliation was substantially reduced. The tethering of PilF to the outer membrane promotes the correct localization of PilQ and appears to be required for the formation of stable T4P. Our 2.0-A structure of PilF revealed a superhelical arrangement of six tetratricopeptide protein-protein interaction motifs that may mediate the contacts with PilQ during secretin assembly. An alignment of pseudomonad PilF sequences revealed three highly conserved surfaces that may be involved in PilF function.

  10. Delineation of polar localization domains of Agrobacterium tumefaciens type IV secretion apparatus proteins VirB4 and VirB11

    PubMed Central

    Das, Aditi; Das, Anath

    2014-01-01

    Agrobacterium tumefaciens transfers DNA and proteins to a plant cell through a type IV secretion apparatus assembled by the VirB proteins. All VirB proteins localized to a cell pole, although these conclusions are in dispute. To study subcellular location of the VirB proteins and to identify determinants of their subcellular location, we tagged two proteins, VirB4 and VirB11, with the visual marker green fluorescent protein (GFP) and studied localization of the fusion proteins by epifluorescence microscopy. Both GFP-VirB4 and GFP-VirB11 fusions localized to a single cell pole. GFP-VirB11 was also functional in DNA transfer. To identify the polar localization domains (PLDs) of VirB4 and VirB11, we analyzed fusions of GFP with smaller segments of the two proteins. Two noncontiguous regions in VirB4, residues 236–470 and 592–789, contain PLDs. The VirB11 PLD mapped to a 69 amino acid segment, residues 149–217, in the central region of the protein. These domains are probably involved in interactions that target the two proteins to a cell pole. PMID:25220247

  11. 3D structure/function analysis of PilX reveals how minor pilins can modulate the virulence properties of type IV pili

    PubMed Central

    Helaine, Sophie; Dyer, David H.; Nassif, Xavier; Pelicic, Vladimir; Forest, Katrina T.

    2007-01-01

    Type IV pili (Tfp) are widespread filamentous bacterial organelles that mediate multiple virulence-related phenotypes. They are composed mainly of pilin subunits, which are processed before filament assembly by dedicated prepilin peptidases. Other proteins processed by these peptidases, whose molecular nature and mode of action remain enigmatic, play critical roles in Tfp biology. We have performed a detailed structure/function analysis of one such protein, PilX from Neisseria meningitidis, which is crucial for formation of bacterial aggregates and adhesion to human cells. The x-ray crystal structure of PilX reveals the α/β roll fold shared by all pilins, and we show that this protein colocalizes with Tfp. These observations suggest that PilX is a minor, or low abundance, pilin that assembles within the filaments in a similar way to pilin. Deletion of a PilX distinctive structural element, which is predicted to be exposed on the filament surface, abolishes aggregation and adhesion. Our results support a model in which surface-exposed motifs in PilX subunits stabilize bacterial aggregates against the disruptive force of pilus retraction and illustrate how a minor pilus component can enhance the functional properties of pili of rather simple composition and structure. PMID:17893339

  12. Fabrication of a Core-Shell-Type Photocatalyst via Photodeposition of Group IV and V Transition Metal Oxyhydroxides: An Effective Surface Modification Method for Overall Water Splitting.

    PubMed

    Takata, Tsuyoshi; Pan, Chengsi; Nakabayashi, Mamiko; Shibata, Naoya; Domen, Kazunari

    2015-08-01

    The design of optimal surface structures for photocatalysts is a key to efficient overall water splitting into H2 and O2. A unique surface modification method was devised for a photocatalyst to effectively promote overall water splitting. Photodeposition of amorphous oxyhydroxides of group IV and V transition metals (Ti, Nb, Ta) over a semiconductor photocatalyst from corresponding water-soluble metal peroxide complexes was examined. In this method, amorphous oxyhydroxide covered the whole surface of the photocatalyst particles, creating a core-shell structure. The water splitting behavior of the novel core-shell-type photocatalyst in relation to the permeation behavior of the coating layer was investigated in detail. Overall water splitting proceeded successfully after the photodeposition, owing to the prevention of the reverse reaction. The photodeposited oxyhydroxide layers were found to function as molecular sieves, selectively filtering reactant and product molecules. By exploiting the selective permeability of the coating layer, redox reactions on the photocatalyst surface could be suitably controlled, which resulted in successful overall water splitting. PMID:26161678

  13. Two novel splicing mutations in the SLC45A2 gene cause Oculocutaneous Albinism Type IV by unmasking cryptic splice sites.

    PubMed

    Straniero, Letizia; Rimoldi, Valeria; Soldà, Giulia; Mauri, Lucia; Manfredini, Emanuela; Andreucci, Elena; Bargiacchi, Sara; Penco, Silvana; Gesu, Giovanni P; Del Longo, Alessandra; Piozzi, Elena; Asselta, Rosanna; Primignani, Paola

    2015-09-01

    Oculocutaneous albinism (OCA) is characterized by hypopigmentation of the skin, hair and eye, and by ophthalmologic abnormalities caused by a deficiency in melanin biosynthesis. OCA type IV (OCA4) is one of the four commonly recognized forms of albinism, and is determined by mutation in the SLC45A2 gene. Here, we investigated the genetic basis of OCA4 in an Italian child. The mutational screening of the SLC45A2 gene identified two novel potentially pathogenic splicing mutations: a synonymous transition (c.888G>A) involving the last nucleotide of exon 3 and a single-nucleotide insertion (c.1156+2dupT) within the consensus sequence of the donor splice site of intron 5. As computer-assisted analysis for mutant splice-site prediction was not conclusive, we investigated the effects on pre-mRNA splicing of these two variants by using an in vitro minigene approach. Production of mutant transcripts in HeLa cells demonstrated that both mutations cause the almost complete abolishment of the physiologic donor splice site, with the concomitant unmasking of cryptic donor splice sites. To our knowledge, this work represents the first in-depth molecular characterization of splicing defects in a OCA4 patient. PMID:26016411

  14. A single bifunctional enzyme, PilD, catalyzes cleavage and N-methylation of proteins belonging to the type IV pilin family.

    PubMed Central

    Strom, M S; Nunn, D N; Lory, S

    1993-01-01

    Precursors of the type IV pilins of a number of bacterial pathogens, as well as related proteins involved in extracellular protein export and DNA uptake, are synthesized with short basic leader sequences. Maturation of these proteins involves two consecutive posttranslational modifications. The leader sequence is first proteolytically removed by specialized endopeptidases, of which the prototype is encoded by the pilD gene of Pseudomonas aeruginosa. Subsequently, the amino termini of these proteins are methylated. Here we demonstrate that PilD, in addition to cleaving the amino-terminal leader sequences of prepilin, also catalyzes N-methylation of the amino-terminal phenylalanine of the mature pilin, using S-adenosyl-L-methionine as a methyl donor. Thus, to our knowledge, PilD is the first characterized bacterial N-methyltransferase. Complete inhibition of N-methylation, but not peptide cleavage, by structural analogues of S-adenosyl-L-methionine suggests that PilD is a bifunctional enzyme with proteolytic and methylation activities carried out within two distinct active sites. Images Fig. 2 Fig. 3 Fig. 5 Fig. 6 PMID:8096341

  15. NMR structure of a complex between the VirB9/VirB7 interaction domains of the pKM101 type IV secretion system.

    PubMed

    Bayliss, Richard; Harris, Richard; Coutte, Loic; Monier, Amy; Fronzes, Remi; Christie, Peter J; Driscoll, Paul C; Waksman, Gabriel

    2007-01-30

    Type IV secretion (T4S) systems translocate DNA and protein effectors through the double membrane of Gram-negative bacteria. The paradigmatic T4S system in Agrobacterium tumefaciens is assembled from 11 VirB subunits and VirD4. Two subunits, VirB9 and VirB7, form an important stabilizing complex in the outer membrane. We describe here the NMR structure of a complex between the C-terminal domain of the VirB9 homolog TraO (TraO(CT)), bound to VirB7-like TraN from plasmid pKM101. TraO(CT) forms a beta-sandwich around which TraN winds. Structure-based mutations in VirB7 and VirB9 of A. tumefaciens show that the heterodimer interface is conserved. Opposite this interface, the TraO structure shows a protruding three-stranded beta-appendage, and here, we supply evidence that the corresponding region of VirB9 of A. tumefaciens inserts in the membrane and protrudes extracellularly. This complex structure elucidates the molecular basis for the interaction between two essential components of a T4S system. PMID:17244707

  16. NMR structure of a complex between the VirB9/VirB7 interaction domains of the pKM101 type IV secretion system

    PubMed Central

    Bayliss, Richard; Harris, Richard; Coutte, Loic; Monier, Amy; Fronzes, Remi; Christie, Peter J.; Driscoll, Paul C.; Waksman, Gabriel

    2007-01-01

    Type IV secretion (T4S) systems translocate DNA and protein effectors through the double membrane of Gram-negative bacteria. The paradigmatic T4S system in Agrobacterium tumefaciens is assembled from 11 VirB subunits and VirD4. Two subunits, VirB9 and VirB7, form an important stabilizing complex in the outer membrane. We describe here the NMR structure of a complex between the C-terminal domain of the VirB9 homolog TraO (TraOCT), bound to VirB7-like TraN from plasmid pKM101. TraOCT forms a β-sandwich around which TraN winds. Structure-based mutations in VirB7 and VirB9 of A. tumefaciens show that the heterodimer interface is conserved. Opposite this interface, the TraO structure shows a protruding three-stranded β-appendage, and here, we supply evidence that the corresponding region of VirB9 of A. tumefaciens inserts in the membrane and protrudes extracellularly. This complex structure elucidates the molecular basis for the interaction between two essential components of a T4S system. PMID:17244707

  17. The Predicted ABC Transporter AbcEDCBA Is Required for Type IV Secretion System Expression and Lysosomal Evasion by Brucella ovis

    PubMed Central

    Silva, Teane M. A.; Mol, Juliana P. S.; Winter, Maria G.; Atluri, Vidya; Xavier, Mariana N.; Pires, Simone F.; Paixão, Tatiane A.; Andrade, Hélida M.; Santos, Renato L.; Tsolis, Renee M.

    2014-01-01

    Brucella ovis is a major cause of reproductive failure in rams and it is one of the few well-described Brucella species that is not zoonotic. Previous work showed that a B. ovis mutant lacking a species-specific ABC transporter (ΔabcBA) was attenuated in mice and was unable to survive in macrophages. The aim of this study was to evaluate the role of this ABC transporter during intracellular survival of B. ovis. In HeLa cells, B. ovis WT was able to survive and replicate at later time point (48 hpi), whereas an ΔabcBA mutant was attenuated at 24 hpi. The reduced survival of the ΔabcBA mutant was associated with a decreased ability to exclude the lysosomal marker LAMP1 from its vacuolar membrane, suggesting a failure to establish a replicative niche. The ΔabcBA mutant showed a reduced abundance of the Type IV secretion system (T4SS) proteins VirB8 and VirB11 in both rich and acid media, when compared to WT B. ovis. However, mRNA levels of virB1, virB8, hutC, and vjbR were similar in both strains. These results support the notion that the ABC transporter encoded by abcEDCBA or its transported substrate acts at a post-transcriptional level to promote the optimal expression of the B. ovis T4SS within infected host cells. PMID:25474545

  18. C-terminal domain of CagX is responsible for its interaction with CagT protein of Helicobacter pylori type IV secretion system.

    PubMed

    Gopal, Gopal Jee; Pal, Jagannath; Kumar, Awanish; Mukhopadhyay, Gauranga

    2015-01-01

    Helicobacter pylori are the well known human pathogen associated with gastric cancer and peptic ulcer. Pathogenesis is mainly due to the presence of 40 kb cagPAI (cag Pathogenicity Island) region that encodes the type IV secretion system (TFSS) consisting of a cytoplasmic part, a middle part/core complex (spans from inner membrane to outer membrane), and an outer membrane associated part. CagX and CagT are two important proteins of TFSS that have homology with virB9 and virB7 of Agrobacterium tumefaciens TFSS. In this study, we have shown that the CagX and CagT interact directly by using co-immunoprecipitation of endogenous CagX and CagT and MBP pull down assay. We further authenticate this observation using yeast two-hybrid assay and co-expression of both the protein coding gene in Escherichia coli. We also observed that the C-terminal region of CagX is important for CagT interaction. We reconfirm that CagT depends on CagX for its stabilization. These observations could contribute in overall visualization of assembly and architecture of TFSS because protein-protein interactions among Cag proteins are likely to have an important role in assembly. Thorough understanding about architecture and mechanism of action of cag-TFSS may lead to design controlled drug delivery system. PMID:25446105

  19. Evidence of the presence of a functional Dot/Icm type IV-B secretion system in the fish bacterial pathogen Piscirickettsia salmonis.

    PubMed

    Gómez, Fernando A; Tobar, Jaime A; Henríquez, Vitalia; Sola, Mariel; Altamirano, Claudia; Marshall, Sergio H

    2013-01-01

    Piscirickettsia salmonis is a fish bacterial pathogen that has severely challenged the sustainability of the Chilean salmon industry since its appearance in 1989. As this Gram-negative bacterium has been poorly characterized, relevant aspects of its life cycle, virulence and pathogenesis must be identified in order to properly design prophylactic procedures. This report provides evidence of the functional presence in P. salmonis of four genes homologous to those described for Dot/Icm Type IV Secretion Systems. The Dot/Icm System, the major virulence mechanism of phylogenetically related pathogens Legionella pneumophila and Coxiella burnetii, is responsible for their intracellular survival and multiplication, conditions that may also apply to P. salmonis. Our results demonstrate that the four P. salmonis dot/icm homologues (dotB, dotA, icmK and icmE) are expressed both during in vitro tissue culture cells infection and growing in cell-free media, suggestive of their putative constitutive expression. Additionally, as it happens in other referential bacterial systems, temporal acidification of cell-free media results in over expression of all four P. salmonis genes, a well-known strategy by which SSTIV-containing bacteria inhibit phagosome-lysosome fusion to survive. These findings are very important to understand the virulence mechanisms of P. salmonis in order to design new prophylactic alternatives to control the disease. PMID:23383004

  20. A type IV P-type ATPase affects insulin-mediated glucose uptake in adipose tissue and skeletal muscle in mice.

    PubMed

    Dhar, Madhu S; Yuan, Joshua S; Elliott, Sarah B; Sommardahl, Carla

    2006-12-01

    Mice carrying two pink-eyed dilution (p) locus heterozygous deletions represent a novel polygenic mouse model of type 2 diabetes associated with obesity. Atp10c, a putative aminophospholipid transporter on mouse chromosome 7, is a candidate for the phenotype. The phenotype is diet-induced. As a next logical step in the validation and characterization of the model, experiments to analyze metabolic abnormalities associated with these mice were carried out. Results demonstrate that mutants (inheriting the p deletion maternally) heterozygous for Atp10c are hyperinsulinemic, insulin-resistant and have an altered insulin-stimulated response in peripheral tissues. Adipose tissue and the skeletal muscle are the targets, and GLUT4-mediated glucose uptake is the specific metabolic pathway associated with Atp10c deletion. Insulin resistance primarily affects the adipose tissue and the skeletal muscle, and the effect in the liver is secondary. Gene expression profiling using microarray and real-time PCR show significant changes in the expression of four genes--Vamp2, Dok1, Glut4 and Mapk14--involved in insulin signaling. The expression of Atp10c is also significantly altered in the adipose tissue and the soleus muscle. The most striking observation is the loss of Atp10c expression in the mutants, specifically in the soleus muscle, after eating the high-fat diet for 12 weeks. In conclusion, experiments suggest that the target genes and/or their cognate factors in conjunction with Atp10c presumably affect the normal translocation and sequestration of GLUT4 in both the target tissues. PMID:16517145

  1. Crystallization and X-ray diffraction analysis of a novel immune-type receptor from Ictalurus punctatus and phasing by selenium anomalous dispersion methods

    SciTech Connect

    Ostrov, David A. Hernández Prada, José A.; Haire, Robert N.; Magis, Andrew T.; Bailey, Kate; Litman, Gary W.

    2007-12-01

    A highly diversified novel immune-type receptor from catfish, NITR10, was crystallized to reveal novel mechanisms of immune recognition. X-ray diffraction data from crystals of a novel immune-type receptor (NITR10 from the catfish Ictalurus punctatus) were collected to 1.65 Å resolution and reduced to the primitive hexagonal lattice. Native and selenomethionine derivatives of NITR10 crystallized under different conditions yielded P3{sub 1}21 crystals. SeMet NITR10 was phased to a correlation coefficient of 0.77 by SAD methods and experimental electron-density maps were calculated to 1.65 Å. Five NITR10 molecules are predicted to be present in the asymmetric unit based on the Matthews coefficient.

  2. Beta function and anomalous dimensions

    SciTech Connect

    Pica, Claudio; Sannino, Francesco

    2011-06-01

    We demonstrate that it is possible to determine the coefficients of an all-orders beta-function linear in the anomalous dimensions using as data the 2-loop coefficients together with the first one of the anomalous dimensions which are universal. The beta function allows us to determine the anomalous dimension of the fermion masses at the infrared fixed point, and the resulting values compare well with the lattice determinations.

  3. Flashing anomalous color contrast.

    PubMed

    Pinna, Baingio; Spillmann, Lothar; Werner, John S

    2004-01-01

    A new visual phenomenon that we call flashing anomalous color contrast is described. This phenomenon arises from the interaction between a gray central disk and a chromatic annulus surrounded by black radial lines. In an array of such figures, the central gray disk no longer appears gray, but assumes a color complementary to that of the surrounding annulus. The induced color appears: (1) vivid and saturated; (2) self-luminous, not a surface property; (3) flashing with eye or stimulus movement; (4) floating out of its confines; and (5) stronger in extrafoveal than in foveal vision. The strength of the effect depends on the number, length, width, and luminance contrast of the radial lines. The results suggest that the chromatic ring bounding the inner tips of the black radial lines induces simultaneous color contrast, whereas the radial lines elicit, in conjunction with the gray disk and the ring, the flashing, vividness, and high saturation of the effect. The stimulus properties inducing the illusion suggest that flashing anomalous color contrast may be based on asynchronous interactions among multiple visual pathways. PMID:15518215

  4. Fickian dispersion is anomalous

    SciTech Connect

    Cushman, John H.; O’Malley, Dan

    2015-06-22

    The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Finally, power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.

  5. Fickian dispersion is anomalous

    DOE PAGESBeta

    Cushman, John H.; O’Malley, Dan

    2015-06-22

    The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion wemore » illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Finally, power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.« less

  6. Asteroids IV

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    . Asteroids, like planets, are driven by a great variety of both dynamical and physical mechanisms. In fact, images sent back by space missions show a collection of small worlds whose characteristics seem designed to overthrow our preconceived notions. Given their wide range of sizes and surface compositions, it is clear that many formed in very different places and at different times within the solar nebula. These characteristics make them an exciting challenge for researchers who crave complex problems. The return of samples from these bodies may ultimately be needed to provide us with solutions. In the book Asteroids IV, the editors and authors have taken major strides in the long journey toward a much deeper understanding of our fascinating planetary ancestors. This book reviews major advances in 43 chapters that have been written and reviewed by a team of more than 200 international authorities in asteroids. It is aimed to be as comprehensive as possible while also remaining accessible to students and researchers who are interested in learning about these small but nonetheless important worlds. We hope this volume will serve as a leading reference on the topic of asteroids for the decade to come. We are deeply indebted to the many authors and referees for their tremendous efforts in helping us create Asteroids IV. We also thank the members of the Asteroids IV scientific organizing committee for helping us shape the structure and content of the book. The conference associated with the book, "Asteroids Comets Meteors 2014" held June 30-July 4, 2014, in Helsinki, Finland, did an outstanding job of demonstrating how much progress we have made in the field over the last decade. We are extremely grateful to our host Karri Muinonnen and his team. The editors are also grateful to the Asteroids IV production staff, namely Renée Dotson and her colleagues at the Lunar and Planetary Institute, for their efforts, their invaluable assistance, and their enthusiasm; they made life as

  7. Asteroids IV

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    . Asteroids, like planets, are driven by a great variety of both dynamical and physical mechanisms. In fact, images sent back by space missions show a collection of small worlds whose characteristics seem designed to overthrow our preconceived notions. Given their wide range of sizes and surface compositions, it is clear that many formed in very different places and at different times within the solar nebula. These characteristics make them an exciting challenge for researchers who crave complex problems. The return of samples from these bodies may ultimately be needed to provide us with solutions. In the book Asteroids IV, the editors and authors have taken major strides in the long journey toward a much deeper understanding of our fascinating planetary ancestors. This book reviews major advances in 43 chapters that have been written and reviewed by a team of more than 200 international authorities in asteroids. It is aimed to be as comprehensive as possible while also remaining accessible to students and researchers who are interested in learning about these small but nonetheless important worlds. We hope this volume will serve as a leading reference on the topic of asteroids for the decade to come. We are deeply indebted to the many authors and referees for their tremendous efforts in helping us create Asteroids IV. We also thank the members of the Asteroids IV scientific organizing committee for helping us shape the structure and content of the book. The conference associated with the book, "Asteroids Comets Meteors 2014" held June 30-July 4, 2014, in Helsinki, Finland, did an outstanding job of demonstrating how much progress we have made in the field over the last decade. We are extremely grateful to our host Karri Muinonnen and his team. The editors are also grateful to the Asteroids IV production staff, namely Renée Dotson and her colleagues at the Lunar and Planetary Institute, for their efforts, their invaluable assistance, and their enthusiasm; they made life as

  8. Anomalous Charge Transport in Disordered Organic Semiconductors

    SciTech Connect

    Muniandy, S. V.; Woon, K. L.; Choo, K. Y.

    2011-03-30

    Anomalous charge carrier transport in disordered organic semiconductors is studied using fractional differential equations. The connection between index of fractional derivative and dispersion exponent is examined from the perspective of fractional Fokker-Planck equation and its link to the continuous time random walk formalism. The fractional model is used to describe the bi-scaling power-laws observed in the time-of flight photo-current transient data for two different types of organic semiconductors.

  9. Feasibility and effectiveness of the implementation of a primary prevention programme for type 2 diabetes in routine primary care practice: a phase IV cluster randomised clinical trial

    PubMed Central

    2012-01-01

    Background The objective of this study is to perform an independent evaluation of the feasibility and effectiveness of an educational programme for the primary prevention of type 2 diabetes (DM2) in high risk populations in primary care settings, implanted within the Basque Health Service - Osakidetza. Methods/design This is a prospective phase IV cluster clinical trial conducted under routine conditions in 14 primary health care centres of Osakidetza, randomly assigned to an intervention or control group. We will recruit a total sample of 1089 individuals, aged between 45 and 70 years old, without diabetes but at high risk of developing the condition (Finnish Diabetes Risk Score, FINDRISC ≥ 14) and follow them up for 2 years. Primary health care nursing teams of the intervention centres will implement DE-PLAN, a structured educational intervention program focused on changing healthy lifestyles (diet and physical activity); while the patients in the control centres will receive the usual care for the prevention and treatment of DM2 currently provided in Osakidetza. The effectiveness attributable to the programme will be assessed by comparing the changes observed in patients exposed to the intervention and those in the control group, with respect to the risk of developing DM2 and lifestyle habits. In terms of feasibility, we will assess indicators of population coverage and programme implementation. Discussion The aim of this study is to provide the scientific basis for disseminate the programme to the remaining primary health centres in Osakidetza, as a novel way of addressing prevention of DM2. The study design will enable us to gather information on the effectiveness of the intervention as well as the feasibility of implementing it in routine practice. Trial registration ClinicalTrials.gov NCT01365013 PMID:23158830

  10. Transfer of R388 Derivatives by a Pathogenesis-Associated Type IV Secretion System into both Bacteria and Human Cells ▿

    PubMed Central

    Fernández-González, Esther; de Paz, Héctor D.; Alperi, Anabel; Agúndez, Leticia; Faustmann, Marco; Sangari, Félix J.; Dehio, Christoph; Llosa, Matxalen

    2011-01-01

    Bacterial type IV secretion systems (T4SSs) are involved in processes such as bacterial conjugation and protein translocation to animal cells. In this work, we have switched the substrates of T4SSs involved in pathogenicity for DNA transfer. Plasmids containing part of the conjugative machinery of plasmid R388 were transferred by the T4SS of human facultative intracellular pathogen Bartonella henselae to both recipient bacteria and human vascular endothelial cells. About 2% of the human cells expressed a green fluorescent protein (GFP) gene from the plasmid. Plasmids of different sizes were transferred with similar efficiencies. B. henselae codes for two T4SSs: VirB/VirD4 and Trw. A ΔvirB mutant strain was transfer deficient, while a ΔtrwE mutant was only slightly impaired in DNA transfer. DNA transfer was in all cases dependent on protein TrwC of R388, the conjugative relaxase, implying that it occurs by a conjugation-like mechanism. A DNA helicase-deficient mutant of TrwC could not promote DNA transfer. In the absence of TrwB, the coupling protein of R388, DNA transfer efficiency dropped 1 log. The same low efficiency was obtained with a TrwB point mutation in the region involved in interaction with the T4SS. TrwB interacted with VirB10 in a bacterial two-hybrid assay, suggesting that it may act as the recruiter of the R388 substrate for the VirB/VirD4 T4SS. A TrwB ATPase mutant behaved as dominant negative, dropping DNA transfer efficiency to almost null levels. B. henselae bacteria recovered from infected human cells could transfer the mobilizable plasmid into recipient Escherichia coli under certain conditions, underscoring the versatility of T4SSs. PMID:21908662

  11. Animal Protection and Structural Studies of a Consensus Sequence VaccineTargeting the Receptor Binding Domain of the Type IV Pilus of Pseudomonas aeruginosa

    PubMed Central

    Kao, Daniel J.; Churchill, Mair E. A.; Irvin, Randall T.; Hodges, Robert S.

    2010-01-01

    One of the main obstacles in the development of a vaccine against Pseudomonas aeruginosa is the requirement that it is protective against a wide range of virulent strains. We have developed a synthetic-peptide consensus-sequence vaccine (Cs1) that targets the host receptor-binding domain (RBD) of the type IV pilus of P. aeruginosa. Here, we show that this vaccine provides increased protection against challenge by the four piliated strains that we have examined (PAK, PAO, KB7 and P1) in the A.BY/SnJ mouse model of acute P. aeruginosa infection. To further characterize the consensus sequence, we engineered Cs1 into the PAK monomeric pilin protein and determined the crystal structure of the chimeric Cs1 pilin to 1.35 Å resolution. The substitutions (T130K and E135P) used to create Cs1 do not disrupt the conserved backbone conformation of the pilin RBD. In fact, based on the Cs1 pilin structure, we hypothesize that the E135P substitution bolsters the conserved backbone conformation and may partially explain the immunological activity of Cs1. Structural analysis of Cs1, PAK and K122-4 pilins reveal substitutions of non-conserved residues in the RBD are compensated for by complementary changes in the rest of the pilin monomer. Thus, the interactions between the RBD and the rest of the pilin can either be mediated by polar interactions of a hydrogen bond network in some strains or by hydrophobic interactions in others. Both configurations maintain a conserved backbone conformation of the RBD. Thus, the backbone conformation is critical in our consensus-sequence vaccine design and that cross-reactivity of the antibody response may be modulated by the composition of exposed side-chains on the surface of the RBD. This structure will guide our future vaccine design by focusing our investigation on the four variable residue positions that are exposed on the RBD surface. PMID:17936788

  12. Mating pair formation homologue TraG is a variable membrane protein essential for contact-independent type IV secretion of chromosomal DNA by Neisseria gonorrhoeae.

    PubMed

    Kohler, Petra L; Chan, Yolande A; Hackett, Kathleen T; Turner, Nicholas; Hamilton, Holly L; Cloud-Hansen, Karen A; Dillard, Joseph P

    2013-04-01

    Neisseria gonorrhoeae uses a type IV secretion system (T4SS) to secrete chromosomal DNA into the surrounding milieu. The DNA is effective in transforming gonococci in the population, and this mechanism of DNA donation may contribute to the high degree of genetic diversity in this species. Similar to other F-like T4SSs, the gonococcal T4SS requires a putative membrane protein, TraG, for DNA transfer. In F-plasmid and related systems, the homologous protein acts in pilus production, mating pair stabilization, and entry exclusion. We characterized the localization, membrane topology, and variation of TraG in N. gonorrhoeae. TraG was found to be an inner-membrane protein with one large periplasmic region and one large cytoplasmic region. Each gonococcal strain carried one of three different alleles of traG. Strains that carried the smallest allele of traG were found to lack the peptidoglycanase gene atlA but carried a peptidoglycan endopeptidase gene in place of atlA. The purified endopeptidase degraded gonococcal peptidoglycan in vitro, cutting the peptide cross-links. Although the other two traG alleles functioned for DNA secretion in strain MS11, the smallest traG did not support DNA secretion. Despite the requirement for a mating pair stabilization homologue, static coculture transformation experiments demonstrated that DNA transfer was nuclease sensitive and required active uptake by the recipient, thus demonstrating that transfer occurred by transformation and not conjugation. Together, these results demonstrate the TraG acts in a process of DNA export not specific to conjugation and that different forms of TraG affect what substrates can be transported. PMID:23378511

  13. An inhibitor of DNA binding and uptake events dictates the proficiency of genetic transformation in Neisseria gonorrhoeae: mechanism of action and links to Type IV pilus expression.

    PubMed

    Aas, Finn Erik; Løvold, Cecilia; Koomey, Michael

    2002-12-01

    Although natural genetic transformation is a widely disseminated form of genetic exchange in prokaryotic species, the proficiencies with which DNA recognition, uptake and processing occur in nature vary greatly. However, the molecular factors and interactions underlying intra- and interspecies diversity in levels of competence for natural genetic transformation are poorly understood. In Neisseria gonorrhoeae, the Gram-negative aetiologic agent of gonorrhoea, DNA binding and uptake involve components required for Type IV pilus (Tfp) biogenesis as well as those which are structurally related to Tfp biogenesis components but dispensable for organelle expression. We demonstrate here that the gonococcal PilV protein, structurally related to Tfp pilin subunits, is an intrinsic inhibitor of natural genetic transformation which acts ultimately by reducing the levels of sequence-specific DNA uptake into the cell. Specifically, we show that DNA uptake is enhanced in strains bearing pilV mutations and reduced in strains overexpressing PilV. Furthermore, we show that PilV exerts its effect by acting as an antagonist of ComP, a positive effector of sequence-specific DNA binding. As it prevents the accumulation of ComP at a site where it can be purified by shear extraction of intact cells, the data are most consistent with PilV either obstructing ComP trafficking or altering ComP stability. In addition, we report that ComP and PilV play overlapping and partially redundant roles in Tfp biogenesis and document other genetic interactions between comP and pilV together with the pilE and pilT genes required for the expression of retractile Tfp. Together, the results reveal a novel mechanism by which the levels of competence are governed in prokaryotic species and suggest unique ways by which competence might be modulated. PMID:12453228

  14. Development and application of pathovar-specific monoclonal antibodies that recognize the lipopolysaccharide O antigen and the type IV fimbriae of Xanthomonas hyacinthi

    SciTech Connect

    Doorn, J. van; Ojanen-Reuhs, T.; Hollinger, T.C.; Reuhs, B.L.; Schots, A.; Boonekamp, P.M.; Oudega, B.

    1999-09-01

    The objective of this study was to develop a specific immunological diagnostic assay for yellow disease in hyacinths, using monoclonal antibodies (MAbs). Mice were immunized with a crude cell wall preparation (shear fraction) from Xanthomonas hyacinthi and with purified type IV fimbriae. Hybridomas were screened for a positive reaction with X. hyacinthi cells or fimbriae and for a negative reaction with X. translucens pv. graminis or Erwinia carotovora subsp. carotovora. Nine MAbs recognized fimbrial epitopes, as shown by immunoblotting, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), and immunoelectron microscopy; however, three of these MAbs had weak cross-reactions with two X. translucens pathovars in immunoblotting experiments. Seven MAbs reacted with lipopolysaccharides and yielded a low-mobility ladder pattern on immunoblots. Subsequent analysis of MAb 2E5 showed that it specifically recognized an epitope on the O antigen, which was found to consist of rhamnose and fucose in a 2:1 molar ratio. The cross-reaction of MAb 2E5 with all X. hyacinthi strains tested showed that this O antigen is highly conserved within this species. MAb 1B10 also reacted with lipopolysaccharides. MAbs 2E5 and 1B10 were further tested in ELISA and immunoblotting experiments with cells and extracts from other pathogens. No cross-reaction was found with 27 other Xanthomonas pathovars tested or with 14 other bacterial species from other genera, such as Erwinia and Pseudomonas, indicating the high specificity of these antibodies. MAbs 2E5 and 1B10 were shown to be useful in ELISA for the detection of X. hyacinthi in infected hyacinths.

  15. Animal Protection and Structural Studies of a Consensus Sequence Vaccine Targeting the Receptor Binding Domain of the Type IV Pilus of Pseudomonas aeruginosa

    SciTech Connect

    Kao, Daniel J.; Churchill, Mair E.A.; Irvin, Randall T.; Hodges, Robert S.

    2008-09-23

    One of the main obstacles in the development of a vaccine against Pseudomonas aeruginosa is the requirement that it is protective against a wide range of virulent strains. We have developed a synthetic-peptide consensus-sequence vaccine (Cs1) that targets the host receptor-binding domain (RBD) of the type IV pilus of P. aeruginosa. Here, we show that this vaccine provides increased protection against challenge by the four piliated strains that we have examined (PAK, PAO, KB7 and P1) in the A.BY/SnJ mouse model of acute P. aeruginosa infection. To further characterize the consensus sequence, we engineered Cs1 into the PAK monomeric pilin protein and determined the crystal structure of the chimeric Cs1 pilin to 1.35 {angstrom} resolution. The substitutions (T130K and E135P) used to create Cs1 do not disrupt the conserved backbone conformation of the pilin RBD. In fact, based on the Cs1 pilin structure, we hypothesize that the E135P substitution bolsters the conserved backbone conformation and may partially explain the immunological activity of Cs1. Structural analysis of Cs1, PAK and K122-4 pilins reveal substitutions of non-conserved residues in the RBD are compensated for by complementary changes in the rest of the pilin monomer. Thus, the interactions between the RBD and the rest of the pilin can either be mediated by polar interactions of a hydrogen bond network in some strains or by hydrophobic interactions in others. Both configurations maintain a conserved backbone conformation of the RBD. Thus, the backbone conformation is critical in our consensus-sequence vaccine design and that cross-reactivity of the antibody response may be modulated by the composition of exposed side-chains on the surface of the RBD. This structure will guide our future vaccine design by focusing our investigation on the four variable residue positions that are exposed on the RBD surface.

  16. Development and Application of Pathovar-Specific Monoclonal Antibodies That Recognize the Lipopolysaccharide O Antigen and the Type IV Fimbriae of Xanthomonas hyacinthi

    PubMed Central

    van Doorn, J.; Ojanen-Reuhs, T.; Hollinger, T. C.; Reuhs, B. L.; Schots, A.; Boonekamp, P. M.; Oudega, B.

    1999-01-01

    The objective of this study was to develop a specific immunological diagnostic assay for yellow disease in hyacinths, using monoclonal antibodies (MAbs). Mice were immunized with a crude cell wall preparation (shear fraction) from Xanthomonas hyacinthi and with purified type IV fimbriae. Hybridomas were screened for a positive reaction with X. hyacinthi cells or fimbriae and for a negative reaction with X. translucens pv. graminis or Erwinia carotovora subsp. carotovora. Nine MAbs recognized fimbrial epitopes, as shown by immunoblotting, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), and immunoelectron microscopy; however, three of these MAbs had weak cross-reactions with two X. translucens pathovars in immunoblotting experiments. Seven MAbs reacted with lipopolysaccharides and yielded a low-mobility ladder pattern on immunoblots. Subsequent analysis of MAb 2E5 showed that it specifically recognized an epitope on the O antigen, which was found to consist of rhamnose and fucose in a 2:1 molar ratio. The cross-reaction of MAb 2E5 with all X. hyacinthi strains tested showed that this O antigen is highly conserved within this species. MAb 1B10 also reacted with lipopolysaccharides. MAbs 2E5 and 1B10 were further tested in ELISA and immunoblotting experiments with cells and extracts from other pathogens. No cross-reaction was found with 27 other Xanthomonas pathovars tested or with 14 other bacterial species from other genera, such as Erwinia and Pseudomonas, indicating the high specificity of these antibodies. MAbs 2E5 and 1B10 were shown to be useful in ELISA for the detection of X. hyacinthi in infected hyacinths. PMID:10473431

  17. Large-scale study of the interactions between proteins involved in type IV pilus biology in Neisseria meningitidis: characterization of a subcomplex involved in pilus assembly.

    PubMed

    Georgiadou, Michaella; Castagnini, Marta; Karimova, Gouzel; Ladant, Daniel; Pelicic, Vladimir

    2012-06-01

    The functionally versatile type IV pili (Tfp) are one of the most widespread virulence factors in bacteria. However, despite generating much research interest for decades, the molecular mechanisms underpinning the various aspects of Tfp biology remain poorly understood, mainly because of the complexity of the system. In the human pathogen Neisseria meningitidis for example, 23 proteins are dedicated to Tfp biology, 15 of which are essential for pilus biogenesis. One of the important gaps in our knowledge concerns the topology of this multiprotein machinery. Here we have used a bacterial two-hybrid system to identify and quantify the interactions between 11 Pil proteins from N. meningitidis. We identified 20 different binary interactions, many of which are novel. This represents the most complex interaction network between Pil proteins reported to date and indicates, among other things, that PilE, PilM, PilN and PilO, which are involved in pilus assembly, indeed interact. We focused our efforts on this subset of proteins and used a battery of assays to determine the membrane topology of PilN and PilO, map the interaction domains between PilE, PilM, PilN and PilO, and show that a widely conserved N-terminal motif in PilN is essential for both PilM-PilN interactions and pilus assembly. Finally, we show that PilP (another protein involved in pilus assembly) forms a complex with PilM, PilN and PilO. Taken together, these findings have numerous implications for understanding Tfp biology and provide a useful blueprint for future studies. PMID:22486968

  18. Structure of the human type IV collagen COL4A6 gene, which is mutated in Alport syndrome-associated leiomyomatosis

    SciTech Connect

    Zhang, Xu |; Zhou, Jing; Reeders, S.T.

    1996-05-01

    Basement membrane (type IV) collagen, a subfamily of the collagen protein family, is encoded by six distinct genes in mammals. Three of those, COL4A3, COL4A4, and COL4A5, are linked with Alport syndrome (hereditary nephritis). Patients with leimoyomatosis associated with Alport syndrome have been shown to have deletions in the 5{prime} end of the COL4A6 gene, in addition to having deletions in COL4A6. The human COL4A6 gene is reported to be 425 kb as determined by mapping of overlapping YAC clones by probes for its 5{prime} and 3{prime} ends. In the present study we describe the complete exon/intron size pattern of the human COL4A6 gene. The 12 {lambda} phage clones characterized in the study spanned a total of 110 kb, including 85 kb of the actual gene and 25 kb of flanking sequences. The overlapping clones contained all 46 exons of the gene and all introns, except for intron 2. Since the total size of the exons and all introns except for intron 2 is about 85 kb, intron 2 must be about 340 kb. All exons of the gene were assigned to EcoRI restriction fragments to facilitate analysis of the gene in patients with leiomyomatosis associated with Alport syndrome. The exon size pattern of COL4A6 is highly homologous with that of the human and mouse COL4A2 genes, with 27 of the 46 exons of COL4A6 being identical in size between the genes. 42 refs., 2 figs., 3 tabs.

  19. Conjugative DNA transfer into human cells by the VirB/VirD4 type IV secretion system of the bacterial pathogen Bartonella henselae

    PubMed Central

    Schröder, Gunnar; Schuelein, Ralf; Quebatte, Maxime; Dehio, Christoph

    2011-01-01

    Bacterial type IV secretion systems (T4SS) mediate interbacterial conjugative DNA transfer and transkingdom protein transfer into eukaryotic host cells in bacterial pathogenesis. The sole bacterium known to naturally transfer DNA into eukaryotic host cells via a T4SS is the plant pathogen Agrobacterium tumefaciens. Here we demonstrate T4SS-mediated DNA transfer from a human bacterial pathogen into human cells. We show that the zoonotic pathogen Bartonella henselae can transfer a cryptic plasmid occurring in the bartonellae into the human endothelial cell line EA.hy926 via its T4SS VirB/VirD4. DNA transfer into EA.hy926 cells was demonstrated by using a reporter derivative of this Bartonella-specific mobilizable plasmid generated by insertion of a eukaryotic egfp-expression cassette. Fusion of the C-terminal secretion signal of the endogenous VirB/VirD4 protein substrate BepD with the plasmid-encoded DNA-transport protein Mob resulted in a 100-fold increased DNA transfer rate. Expression of the delivered egfp gene in EA.hy926 cells required cell division, suggesting that nuclear envelope breakdown may facilitate passive entry of the transferred ssDNA into the nucleus as prerequisite for complementary strand synthesis and transcription of the egfp gene. Addition of an eukaryotic neomycin phosphotransferase expression cassette to the reporter plasmid facilitated selection of stable transgenic EA.hy926 cell lines that display chromosomal integration of the transferred plasmid DNA. Our data suggest that T4SS-dependent DNA transfer into host cells may occur naturally during human infection with Bartonella and that these chronically infecting pathogens have potential for the engineering of in vivo gene-delivery vectors with applications in DNA vaccination and therapeutic gene therapy. PMID:21844337

  20. High resolution electron microscopy of the Helicobacter pylori Cag type IV secretion system pili produced in varying conditions of iron availability.

    PubMed

    Haley, Kathryn Patricia; Blanz, Eric Joshua; Gaddy, Jennifer Angeline

    2014-01-01

    Helicobacter pylori is a helical-shaped, gram negative bacterium that colonizes the human gastric niche of half of the human population. H. pylori is the primary cause of gastric cancer, the second leading cause of cancer-related deaths worldwide. One virulence factor that has been associated with increased risk of gastric disease is the Cag-pathogenicity island, a 40-kb region within the chromosome of H. pylori that encodes a type IV secretion system and the cognate effector molecule, CagA. The Cag-T4SS is responsible for translocating CagA and peptidoglycan into host epithelial cells. The activity of the Cag-T4SS results in numerous changes in host cell biology including upregulation of cytokine expression, activation of proinflammatory pathways, cytoskeletal remodeling, and induction of oncogenic cell-signaling networks. The Cag-T4SS is a macromolecular machine comprised of sub-assembly components spanning the inner and outer membrane and extending outward from the cell into the extracellular space. The extracellular portion of the Cag-T4SS is referred to as the "pilus". Numerous studies have demonstrated that the Cag-T4SS pili are formed at the host-pathogen interface(. However, the environmental features that regulate the biogenesis of this important organelle remain largely obscure. Recently, we reported that conditions of low iron availability increased the Cag-T4SS activity and pilus biogenesis. Here we present an optimized protocol to grow H. pylori in varying conditions of iron availability prior to co-culture with human gastric epithelial cells. Further, we present the comprehensive protocol for visualization of the hyper-piliated phenotype exhibited in iron restricted conditions by high resolution scanning electron microscopy analyses. PMID:25489938

  1. Anomalous reflections from the ionosphere

    NASA Astrophysics Data System (ADS)

    Givishvili, G. V.; Leshchenko, L. N.

    2013-09-01

    The existence of anomalous ionospheric reflections was shown on the basis of vertical soundings at the Moskow station. They are observed at heights of 100-200 km. These anomalous reflections are not related to the main Ne( h) ionospheric profile. Morphological characteristics of such reflections are presented: the daily, seasonal, and cyclic dependences of their appearance.

  2. Anomalous electrodynamic explosions in liquids

    SciTech Connect

    Aspden, H.

    1986-06-01

    The recently reported Graneau experiments on electrodynamic explosions in liquids, which reveal anomalous longitudinal electrodynamic forces of the order of 10/sup 4/ times greater than expected, verify the need for a term in the law of electrodynamics that corresponds to the ion/electron mass ratio. This confirms an earlier theoretical interpretation of the anomalous cathode reaction forces found in the vacuum arc.

  3. Analysis of conductivity and dielectric spectra of Mn0.5Zn0.5Fe2O4 with coupled Cole-Cole type anomalous relaxations

    NASA Astrophysics Data System (ADS)

    Kumar, N. S. K.; Shahid, T. S.; Govindaraj, G.

    2016-05-01

    Most of the crystalline materials seldom show a well-defined dielectric loss peak due to domination of dc conductivity contribution, but effects of loss peaks are seen at high frequencies. Ac electrical data of nano-crystalline Mn0.5Zn0.5Fe2O4 synthesised by chemical co-precipitation method show such behaviour. Properly combined and formulated conduction and dielectric relaxation functions are required for such materials. Cole-Cole type relaxation function in the combined conduction and dielectric process is formulated for complex resistivity ρ*(ω), complex permittivity ε*(ω), complex conductivity σ*(ω) and complex electric modulus M*(ω). Conduction and dielectric relaxation are linked to Jonscher's idea of 'pinned dipole' and 'free dipole' to understand the relaxation dynamics. The physical parameters of 'pinned dipole' and 'free dipole' formalism are unique for all representations like ρ*(ω), ε*(ω), σ*(ω) and M*(ω). 'Pinned dipole' relaxation time τc related to conduction process and 'free dipole' relaxation time τd related to dielectric process show Arrhenius behaviour with the same activation energy. Correlation of dc conductivity σc with τc and τd indicates the coupled dynamics of 'pinned dipole' and 'free dipole'. Time-temperature scaling of conduction and dielectric relaxation reveals that the mechanism of coupled dynamics of 'pinned dipole' and 'free dipole' is temperature independent. Hopping of charge carriers with dynamics of disordered cation distribution of host matrix generates a coupled conduction and dielectric relaxation in Mn0.5Zn0.5Fe2O4.

  4. Substitution of Aspartate for glycine 1018 in the Type III procollagen (COL3AI) gene causes type IV Ehlers-Danlos Syndrome: The mutated allele is present in most blood leukocytes of the asymptomatic and mosaic mother

    SciTech Connect

    Kontusaari, S.; Tromp, G.; Kuivaniemi, H.; Prockop, D.J. ); Stolle, C. ); Pope, F.M.

    1992-09-01

    A proband with arterial ruptures and skin changes characteristic of the type IV variant of Ehlers-Danlos syndrome was found to have a single-base mutation in the type III procollagen gene, which converted the codon for glycine at amino position 1018 to a codon for aspartate. (Amino acid positions are numbered by the standard convention in which the first glycine of the triple-helical domain of an [alpha] chain is number 1. The numbers of positions in the [alpha]1(III) chains can be converted to positions in the human pro[alpha](III) chain by adding 167.). Nucleotide sequencing of overlapping PCR products in which the two alleles were distinguished demonstrated that the mutation of glycine 1018 was the only mutation that changed the primary structure of type III procollagen. The glycine substitution markedly decreased the amount of type III procollagen secreted into the medium by cultured skin fibroblasts from the proband. It is surprising that the same mutation was found in about 94% of the peripheral blood leukocytes from the proband's asymptomatic 72-year-old mother. Other tissues from the mother contained the mutated allele; it was present in 0%-100% of different samples of hair cells and in about 40% of cells from the oral epithelium. Therefore, the mother was a mosaic for the mutation. Since the mutated allele was present in cells derived from all three germ layers, the results indicated that the mutation arose by the late blastocyst stage of development. The results also indicate that assays of blood leukocytes do not always reveal mosaicism or predict phenotypic involvement of tissues, such as blood vessels, that are derived from the same embryonic cells as are leukocytes. 66 refs., 6 figs., 1 tab.

  5. Spectrum of anomalous magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Giovannini, Massimo

    2016-05-01

    The equations of anomalous magnetohydrodynamics describe an Abelian plasma where conduction and chiral currents are simultaneously present and constrained by the second law of thermodynamics. At high frequencies the magnetic currents play the leading role, and the spectrum is dominated by two-fluid effects. The system behaves instead as a single fluid in the low-frequency regime where the vortical currents induce potentially large hypermagnetic fields. After deriving the physical solutions of the generalized Appleton-Hartree equation, the corresponding dispersion relations are scrutinized and compared with the results valid for cold plasmas. Hypermagnetic knots and fluid vortices can be concurrently present at very low frequencies and suggest a qualitatively different dynamics of the hydromagnetic nonlinearities.

  6. Detection of anomalous events

    DOEpatents

    Ferragut, Erik M.; Laska, Jason A.; Bridges, Robert A.

    2016-06-07

    A system is described for receiving a stream of events and scoring the events based on anomalousness and maliciousness (or other classification). The system can include a plurality of anomaly detectors that together implement an algorithm to identify low-probability events and detect atypical traffic patterns. The anomaly detector provides for comparability of disparate sources of data (e.g., network flow data and firewall logs.) Additionally, the anomaly detector allows for regulatability, meaning that the algorithm can be user configurable to adjust a number of false alerts. The anomaly detector can be used for a variety of probability density functions, including normal Gaussian distributions, irregular distributions, as well as functions associated with continuous or discrete variables.

  7. Anomalous gauge boson couplings

    SciTech Connect

    Barklow, T.; Rizzo, T.; Baur, U.

    1997-01-13

    The measurement of anomalous gauge boson self couplings is reviewed for a variety of present and planned accelerators. Sensitivities are compared for these accelerators using models based on the effective Lagrangian approach. The sensitivities described here are for measurement of {open_quotes}generic{close_quotes} parameters {kappa}{sub V}, {lambda}{sub V}, etc., defined in the text. Pre-LHC measurements will not probe these coupling parameters to precision better than O(10{sup -1}). The LHC should be sensitive to better than O(10{sup -2}), while a future NLC should achieve sensitivity of O(10{sup -3}) to O(10{sup -4}) for center of mass energies ranging from 0.5 to 1.5 TeV.

  8. Raman spectra of Cu{sub 2}B{sup II}C{sup IV}X{sub 4}{sup VI} magnetic quaternary semiconductor compounds with tetragonal stannite type structure

    SciTech Connect

    Rincón, C. Quintero, M.; Power, Ch.; Moreno, E.; Quintero, E.; Morocoima, M.; Henao, J. A.; Macías, M. A.

    2015-05-28

    A comparative study of the Raman spectra of Cu{sub 2}B{sup II}C{sup IV}S{sub 4}{sup VI} and Cu{sub 2}B{sup II}C{sup IV}Se{sub 4}{sup VI}(where B = Mn or Fe) magnetic quaternary semiconductor compounds with stannite-type structure (I4{sup ¯}2m) has been done. Most of the fourteen Raman lines expected for these materials were observed in the spectra. The two strongest lines observed have been assigned to the IR inactive A{sub 1}{sup 1} and A{sub 1}{sup 2} stannite modes that originated from the motion of the S or Se anion around the Cu and C{sup IV} cations remaining at rest. The shift in the frequency of these two lines of about 150 cm{sup −1} to lower energies observed in Cu{sub 2}B{sup II}C{sup IV}Se{sub 4}{sup VI} compounds as compared to those in Cu{sub 2}B{sup II}C{sup IV}S{sub 4}{sup VI} ones, can then be explained as due to the anion mass effect. Based on the fact that values of these frequencies depend mainly on anion mass and bond-stretching forces between nearest-neighbor atoms, the vibrational frequencies v{sup ¯}(A{sub 1}{sup 2}) and v{sup ¯}(A{sub 1}{sup 2}) of both modes for several Cu{sub 2}B{sup II}C{sup IV}X{sub 4}{sup VI} stannite compounds (where X = S, Se, or Te) very close to the experimental data reported for these materials were calculated from a simple model that relates these stretching forces to the anion-cation bond-distances.

  9. Splicing defects in the COL3A1 gene: marked preference for 5' (donor) spice-site mutations in patients with exon-skipping mutations and Ehlers-Danlos syndrome type IV.

    PubMed Central

    Schwarze, U; Goldstein, J A; Byers, P H

    1997-01-01

    Ehlers-Danlos syndrome (EDS) type IV results from mutations in the COL3A1 gene, which encodes the constituent chains of type III procollagen. We have identified, in 33 unrelated individuals or families with EDS type IV, mutations that affect splicing, of which 30 are point mutations at splice junctions and 3 are small deletions that remove splice-junction sequences and partial exon sequences. Except for one point mutation at a donor site, which leads to partial intron inclusion, and a single base-pair substitution at an acceptor site, which gives rise to inclusion of the complete upstream intron into the mature mRNA, all mutations result in deletion of a single exon as the only splice alteration. Of the exon-skipping mutations that are due to single base substitutions, which we have identified in 28 separate individuals, only two affect the splice-acceptor site. The underrepresentation of splice acceptor-site mutations suggests that the favored consequence of 3' mutations is the use of an alternative acceptor site that creates a null allele with a premature-termination codon. The phenotypes of those mutations may differ, with respect to either their severity or their symptomatic range, from the usual presentation of EDS type IV and thus have been excluded from analysis. Images Figure 1 Figure 3 Figure 6 PMID:9399899

  10. Hydrothermal synthesis and characterization of the tri-capped and mono-supported pseudo-Keggin-type tungstovanadophosphate: {l_brace}PW{sub 4}{sup VI}W{sub 5}{sup V}V{sub 3}{sup IV}O{sub 40}(V{sup IV}O){sub 3}[Cu(en){sub 2}]{r_brace}{sup 6-}

    SciTech Connect

    Liu Jian; Xu Jianing; Liu Yabing; Lu Yukun; Song Jiangfeng; Zhang Xiao; Cui Xiaobing; Xu Jiqing Wang Tiegang

    2007-12-15

    A novel polyoxometalate [Cu(phen){sub 2}]{sub 3}{l_brace}PW{sub 4}{sup VI}W{sub 5}{sup V}V{sub 3}{sup IV}O{sub 40}(V{sup IV}O){sub 3}[Cu(en){sub 2}]{r_brace}.4H{sub 2}O 1 (en=ethylenediamine, phen=1,10-phenanthroline) has been synthesized hydrothermally and characterized by elemental analysis, IR, XPS, TG, EPR and single-crystal X-ray diffraction analysis. The crystal structure analysis shows that compound 1 contains a novel highly reduced tri-capped and mono-supported pseudo-Keggin-type heteropolyanion, {l_brace}PW{sub 4}{sup VI}W{sub 5}{sup V}V{sub 3}{sup IV}O{sub 40}(V{sup IV}O){sub 3}[Cu(en){sub 2}]{r_brace}{sup 6-}, three [Cu(phen){sub 2}]{sup 2+} cations and four lattice water molecules. They are further linked to form three-dimensional supramolecular networks through extensive hydrogen bonding and {pi}-{pi} stacking interactions. Interestingly, the water dimer and terminal oxygen of the cluster polyanion constitute a beautiful supramolecular helix chain. The heteropolyanion is the first example of tri-capped and mono-supported pseudo-Keggin-type tungstovanadophosphate and the pH value is crucial for obtaining compound 1 in synthetic procedure. - Graphical abstract: A novel complex [Cu(phen){sub 2}]{sub 3}{l_brace}PW{sub 4}{sup VI}W{sub 5}{sup V}V{sub 3}{sup IV}O{sub 40}(V{sup IV}O){sub 3}[Cu(en){sub 2}]{r_brace}.4H{sub 2}O, the first example of tri-capped and mono-supported highly reduced pseudo-Keggin-type tungstovanadophosphate was synthesized under hydrothermal condition. And the heteropolyanions are linked by water dimer and cation [Cu(phen){sub 2}]{sup 2+} through the hydrogen bond forming a three-dimensional (3D) supramolecular network. Interestingly, the water dimer and terminal oxygen of the polyanion cluster constitute a beautiful supramolecular helix chain.

  11. Design, synthesis, biological screening, and molecular docking studies of piperazine-derived constrained inhibitors of DPP-IV for the treatment of type 2 diabetes.

    PubMed

    Kushwaha, Ram N; Srivastava, Rohit; Mishra, Akansha; Rawat, Arun K; Srivastava, Arvind K; Haq, Wahajul; Katti, Seturam B

    2015-04-01

    Novel piperazine-derived conformationally constrained compounds were designed, synthesized, and evaluated for in vitro Dipeptidyl peptidase-IV (DPP-IV) inhibitory activities. From a library of compounds synthesized, 1-(2-(4-(7-Chloro-4-quinolyl)piperazin-1-yl)acetyl)pyrrolidine (2g) was identified as a potential DPP-IV inhibitor exhibiting better inhibitory activity than P32/98, reference inhibitor. The in vivo studies carried out in STZ and db/db mice models indicated that the compound 2g showed moderate antihyperglycemic activity as compared to the marketed drug Sitagliptin. A two-week repeated dose study in db/db mice revealed that compound 2g significantly declined blood glucose levels with no evidence of hypoglycemia risk. Furthermore, it showed improvement in insulin resistance reversal and antidyslipidemic properties. Molecular docking studies established good binding affinity of compound 2g at the DPP-IV active site and are in favor of the observed biological data. These data collectively suggest that compound 2g is a good lead molecule for further optimization studies. PMID:25216392

  12. Application of anomalous diffusion in production of negative ions

    NASA Astrophysics Data System (ADS)

    Jimbo, Kouichi

    1984-11-01

    The production of negative hydrogen ions is investigated in the reflex-type negative ion sources. When anomalous diffusion in the positive column was found by Hoh and Lehnert [Phys. Fluids 3, 600 (1960)], it was pointed out that the large particle loss produced by anomalous diffusion is compensated for by the larger particle production inside the plasma. In the present experiments anomalous diffusion was artificially encouraged by changing the radial electric field inside the reflex discharge. Apparent encouragement of negative ion current by the increase of the density fluctuation amplitude is observed. Twice as much negative ion current was obtained with the artificial encouragement as without. On the other hand, the larger extracted negative ion current was observed with a lower electron temperature, which is calculated from the anomalous diffusion coefficient derived from a simple nonlinear theory. This result is consistent with Wadehra's calculated results [Appl. Phys. Lett. 35, 917 (1979)].

  13. Application of anomalous diffusion in production of negative ions

    SciTech Connect

    Jimbo, K.

    1984-11-01

    The production of negative hydrogen ions is investigated in the reflex-type negative ion sources. When anomalous diffusion in the positive column was found by Hoh and Lehnert (Phys. Fluids 3, 600 (1960)), it was pointed out that the large particle loss produced by anomalous diffusion is compensated for by the larger particle production inside the plasma. In the present experiments anomalous diffusion was artificially encouraged by changing the radial electric field inside the reflex discharge. Apparent encouragement of negative ion current by the increase of the density fluctuation amplitude is observed. Twice as much negative ion current was obtained with the artificial encouragement as without. On the other hand, the larger extracted negative ion current was observed with a lower electron temperature, which is calculated from the anomalous diffusion coefficient derived from a simple nonlinear theory. This result is consistent with Wadehra's calculated results (Appl. Phys. Lett. 35, 917 (1979)).

  14. Anomalous Hall effect

    NASA Astrophysics Data System (ADS)

    Nagaosa, Naoto; Sinova, Jairo; Onoda, Shigeki; MacDonald, A. H.; Ong, N. P.

    2010-04-01

    The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of the Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors have established systematic trends. These two developments, in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of the Berry-phase curvatures and it is therefore an intrinsic quantum-mechanical property of a perfect crystal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. The full modern semiclassical treatment of the AHE is reviewed which incorporates an anomalous contribution to wave-packet group velocity due to momentum-space Berry curvatures and correctly combines the roles of intrinsic and extrinsic (skew-scattering and side-jump) scattering-related mechanisms. In addition, more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms are reviewed, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Building on results from recent experiment and theory, a

  15. Anomalous - viscosity current drive

    DOEpatents

    Stix, Thomas H.;