Oligopeptidase B-dependent signaling mediates host cell invasion by Trypanosoma cruzi

Mammalian cell invasion by the intracellular protozoan parasite Trypanosoma cruzi is mediated by recruitment and fusion of host cell lysosomes, an unusual process that has been proposed to be dependent on the ability of parasites to trigger intracellular free calcium concentration ([Ca2+]i) transients in host cells. Previous work implicated the T.cruzi serine hydrolase oligopeptidase B in the generation of Ca2+-signaling activity in parasite extracts. Here we show that deletion of the gene encoding oligopeptidase B results in a marked defect in host cell invasion and in the establishment of infections in mice. The invasion defect is associated with the inability of oligopeptidase B null mutant trypomastigotes to mobilize Ca2+ from thapsigargin-sensitive stores in mammalian cells. Exogenous recombinant oligopeptidase B reconstitutes the oligopeptidase B-dependent Ca2+ signaling activity in null mutant parasite extracts, demonstrating that this enzyme is responsible for the generation of a signaling agonist for mammalian cells.     

High-Resolution Raman Temperature Measurements in GaAs p-HEMT Multifinger Devices

Self-heating in multifinger GaAs pseudomorphic-HEMT devices was investigated by micro-Raman spectroscopy. The device temperature was probed on the die as a function of applied bias, external heating, and device geometry. The temperature of the top GaAs layer was recorded inside the source-drain gap, as well as on the device periphery using 488-nm laser excitation. Obtained Raman temperatures were found to be higher than infrared thermography results, which is due to the improved spatial resolution of micro-Raman spectroscopy. Thermal resistance and crosstalk in the multifinger devices was evaluated as a function of thermal stress and finger pitch.     

Cytokine dysregulation in the post-Q-fever fatigue syndrome

High levels of protease inhibitors are induced in potato leaves by wounding. These inhibitors, when ingested by Colorado potato beetle (Leptinotarsa decemlineata Say) larvae, induce expression of specific proteolytic activities in the gut. Induced protease activities cannot be inhibited by potato inhibitors and thus enable the insects to overcome this defence mechanism of potato plants. The induced aminopeptidase and endoproteolytic activities both have the characteristics of cysteine proteases. Twenty-one protein inhibitors of different structural types have been examined for their ability to inhibit these activities in vitro. Members of the cystatin superfamily were found to be poor inhibitors of the induced endoproteolytic activities, except for the third domain of human kininogen, which was a fairly strong inhibitor (75% inhibition). The strongest inhibition (85%) of induced endoproteolytic activity was obtained using structurally different thyroglobulin type-1 domain-like inhibitors--equistatin and MHC class II-associated p41 invariant fragment. Experiments performed using three synthetic substrates for endoproteases gave similar results and indicate the existence of at least different endoproteolytic enzymes resistant to potato inhibitors. The induced aminopeptidase activity can be inhibited only by stefin family of inhibitors in cystatin superfamily. In in vivo experiments, Colorado potato beetle larvae fed on equistatin-coated potato leaves were strongly retarded in their growth and almost 50% died after 4 days. This demonstrated the potential of equistatin to protect crops from insect attack.     

Experimental infection of pigs with the newly identified swine hepatitis E virus (swine HEV), but not with human strains of HEV

A novel virus of pigs, swine hepatitis E virus (swine HEV), was recently identified and shown to be antigenically and genetically related to human HEV. In the present study, we attempted to infect specific-pathogen-free (SPF) pigs experimentally with swine HEV or with human strains of HEV. Serum samples collected from naturally infected pigs were used as the source of swine HEV. Pigs inoculated intravenously with serum samples containing swine HEV seroconverted to anti-HEV 4 to 8 weeks postinoculation, and the virus spread to an uninoculated pig. Swine HEV was detected in nasal and rectal swab materials as early as 2 weeks postinoculation and for 4 to 8 weeks thereafter. Viremia appeared 4 to 6 weeks postinoculation and lasted 1 to 3 weeks. The inoculated pigs appeared clinically normal and serum liver enzymes were not significantly elevated. In contrast, pigs were not infected when inoculated intravenously with about 10(5) monkey infectious doses of one of two human strains of HEV (Sar-55 or Mex-14).     

Leadership Behavior and Subordinate Well-Being.

The authors used a longitudinal design to investigate the relation between leadership behavior and the well-being of subordinates. Well-being is conceptualized as people's feelings about themselves and the settings in which they live and work. Staff members (N = 562) of 2 Community Trusts participated 4 times in a 14-month period. Five models were formulated to answer 2 questions: What is the most likely direction of the relation between leadership and well-being, and what is the time frame of this relation? The model with the best fit suggested that leadership behavior and subordinate responses are linked in a feedback loop. Leadership behavior at Time 1 influenced leadership behavior at Time 4. Subordinate well-being at Time 2 synchronously influenced leadership behavior at Time 2. Leadership behavior at Time 4 synchronously influenced subordinate well-being at Time 4. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elevated temperature fracture toughness of Al-Cu-Mg-Ag sheet: Characterization and modeling

The plane-strain initiation fracture toughness (K _JICi ) and plane-stress crack growth resistance of two Al-Cu-Mg-Ag alloy sheets are characterized as a function of temperature by a J-integral method. For AA2519 +Mg+Ag, K _JICi decreases from 32.5 MPa√m at 25 °C to 28.5 MPa√m at 175 °C, while K _JICi for a lower Cu variant increases from 34.2 MPa√m at 25 °C to 36.0 MPa√m at 150 °C. Crack-tip damage in AA2519+Mg+Ag evolves by nucleation and growth of voids from large undissolved Al₂Cu particles, but fracture resistance is controlled by void sheeting coalescence associated with dispersoids. Quantitative fractography, three-dimensional (3-D) reconstruction of fracture surfaces, and metallographic crack profiles indicate that void sheeting is retarded as temperature increases from 25 °C to 150°C, consistent with a rising fracture resistance. Primary microvoids nucleate from smaller constituent particles in the low Cu alloy, and fracture strain increases. A strain-controlled micromechanical model accurately predicts K _JICi as a function of temperature, but includes a critical distance parameter (l*) that is not definable a priori. Nearly constant initiation toughness for AA2519+Mg+Ag is due to rising fracture strain with temperature, which balances the effects of decreasing flow strength, work hardening, and elastic modulus on the crack-tip strain distribution. Ambient temperature toughnesses of the low Cu variant are comparable to those of AA2519+Mg+Ag, despite increased fracture strain, because of reduced constituent spacing and l*.     

Monoclinic zirconia distributions in plasma-sprayed thermal barrier coatings

Phase composition in an air plasma-sprayed Y₂O₃-stabilized ZrO₂ (YSZ) top coating of a thermal barrier coating (TBC) system was characterized. Both the bulk phase content and localized pockets of monoclinic zirconia were measured with Raman spectroscopy. The starting powder consisted of ∼15 vol.% monoclinic zirconia, which decreased to ∼2 vol.% in the as-sprayed coating. Monoclinic zirconia was concentrated in porous pockets that were evenly distributed throughout the TBC. The pockets resulted from the presence of unmelted granules in the starting powder. The potential effect of the distributed monoclinic pockets on TBC performance is discussed.     

The structure and spacing of intra-urban retailing: Austin,Texas

Summary An incomplete hierarchy of shopping centers has been identified for Austin, With consideration of the CBD and planned ribbon developments, a complete hierarchy might well be postulated. The depleted population of lowest level centers has been noted and shown to be not incompatible with the other findings.However, some systematic elements have been deduced from the spacing of these centers. With a map transformation, a greater regularity may be found than had been detected here. But the actual distribution has been explained in terms of uneven densities of opportunities since the hierarchical requirement of central place theory had already been fulfilled. Topological variance in such a map transformation as has been suggested may considerably complicate a solution which could adequately account for the distribution of such transport oriented service centers as shopping centers. Further research on this data with such reordered space, using entropic analysis and evaluating the information contained in several distributions under different transformations might prove interesting. More complete data on shopping centers, particularly opening dates, and for defunct centers, store types and closing dates would aid the evaluation of the validity of the deductions made here.Donald Wade Jones is a Graduate Student, Department of Geography, University of Chicago and was previously a Graduate Student in the Department of Geography, University of Texas, at Austin. Kingsley E. Haynes, is an Assistant Professor, Department of Geography and the Lyndon B. Johnson School of Public Affairs, University of Texas, Austin.The authors would like to thank Dr. M. Woldenberg, Harvard University for his careful comments and suggestions on an earlier version of this paper. Any errors, however, are the sole responsibility of the authors.     

A comparison of internal eliminated sequences in the genes that encode two K(+)-channel isoforms in Paramecium tetraurelia

The Foundation for Growth Science has been controlling the use of GH by its registration system, which includes a scoring system for the eligibility for GH treatment according to the diagnostic criteria for GH deficiency (GHD) established by the Study Group for Hypothalamo-pituitary Disorder of the Ministry of Health and Welfare. Until 1995, 28,876 patients with GHD (19,432 boys and 9,444 girls) had been registered as eligible for GH treatment. The number of patients registered in a year increased gradually till 1990 due to the unlimited hGH supply by recombinant techniques and the change in the criteria for GH treatment and the number registered became stable after 1990. The frequency of GH-treated patients is calculated to be 55.2/100,000 persons (72.2/100,000 in boys and 37.1/100,000 in girls) in patients born between 1960 and 1990. The highest frequency was 148.4/100,000 persons (191.7/ 100,000 boys and 103.7/100,000 girls) in 1981, when 2,278 patients (1,508 boys and 770 girls) were born. Eligibility for GH treatment is assessed according to the scoring system which is basically dependent on peak GH values in provocation tests so that standardization of GH values measured with the various commercial GH kits is required to avoid inequality of patients' access to the treatment. In samples obtained by GRF test in 10 normal volunteers, hGH was measured with seven human GH (hGH) kits at a laboratory center. Since the RIA value has been used historically for the diagnosis of GHD, the mean of two RIA measurements was selected as the basis for the standardization procedure and the linear regression formula was used for each hGH kit. After the freely available supply of hGH obtained by recombinant DNA techniques, the role of the Foundation for Growth Science has changed to avoid hGH abuse. Even with this regulation, the frequency of registered patients may indicate a tendency to GH overuse.     

Topic 1 Structure of materials and control of porosity: influence of processes on the microstructure of materials

The review reports we are publishing result from a collaboration between the following contributors: Topic 1—J. M. Haynes, A. M. Paillère, L. J. Parrott Topic 2—U. Meier, A. M. Brandt, J. Mazars Topic 3—S. Saunders, C. Andrade, P. Eurin. Panel session 1—G. S. Holister, A. Colson Panel session 2 —B. Schrefler, M. Frémond Panel session 3—J. Hanus, P. Jaugey