Innovativeness as a condition for business excellence

Erfolgreich zu sein ist das Ziel jedes Unternehmens. Aber den richtigen Weg zum Erfolg zu wählen ist bereits ein Problem. So sind bei der Wahl eines Führungsmodells in öffentlichen Versorgungsunternehmen spezifische Faktoren zu berücksichtigen. Ein neues Managementmodell, entwickelt vor dem Hintergrund eines Transformationslandes, trägt diesen Anforderungen Rechnung

Estudio de la reacción de la hemoperoxidasa híbrida tipo A de Trypanosoma cruzi (APx-CcP) con peroxinitrito in vitro e in vivo

Trypanosoma cruzi, agente causal de la enfermedad de Chagas, es un parásito intracelular obligado capaz de invadir y proliferar en células de mamíferos. Para establecer la infección, el parásito debe sobrevivir al ataque nitro-oxidativo del macrófago en respuesta a la invasión (generación de superóxido (O2 •- ), peróxido de hidrógeno (H2O2) y peroxinitrito (ONOOH/ONOO- )). Dentro de las enzimas antioxidantes de T. cruzi, se encuentra una hemoperoxidasa (APx-CcP) que incrementa la infectividad parasitaria tanto in vitro como in vivo. Se trata de una peroxidasa híbrida, que reduce H2O2 utilizando ascorbato o citocromo c como sustrato reductor. Motivados por la reactividad de otras hemoperoxidasas con peroxinitrito y dado que la enzima se localiza en la membrana plasmática en las formas infectivas, nos propusimos estudiar la reacción de la APx-CcP con peroxinitrito y su rol en la detoxificación de este oxidante en la infección a macrófagos. Mediante métodos de cinética rápida y de competencia, determinamos que la enzima reacciona rápidamente con el peroxinitrito (k = 3-4 x 106 M-1s -1 , pH 7.4 y 25°C) mediante la formación de un compuesto tipo I (FeIV=O,Trp•+) que detectamos por análisis espectroscópico y experimentos de inmunospin trapping con DMPO. Finalmente evidenciamos que parásitos sobreexpresantes de APx-CcP son más infectivos que los WT en macrófagos inmunoestimulados (IFN-γ/LPS) y que la sobreexpresión de la enzima resulta en una menor detección del oxidante en el macrófago durante la invasión (citometría de flujo, sonda fluoresceína boronato). Los resultados obtenidos en este trabajo indican que la APx-CcP reacciona con el peroxinitrito protegiendo al parásito de sus efectos citotóxicos

Data Watch: Research Data from Transition Economies

http://deepblue.lib.umich.edu/bitstream/2027.42/39800/3/wp416.pd

Hinge and Amino-Terminal Sequences Contribute to Solution Dimerization of Human Progesterone Receptor

We and others have shown previously that progesterone receptors (PR) form homodimers in solution in the absence of DNA and that dimers are the preferential form of receptor that binds with high affinity to target DNA. To determine the sequence regions involved in solution homodimerization, wild type PR and truncated PR proteins were expressed in an insect baculovirus system. The expression constructs included the ligand-binding domain [LBD, amino acids (aa) 688–933], the LBD plus hinge (hLBD, aa 634–933), the hLBD plus the DNA-binding domain (DhLBD, aa 538–933), and the full- length A and B isoforms of PR. PR-PR interactions were detected by three methods, coimmunoprecipitation of the PR fragments with full-length PR-A, pull-down of PR-polypeptides with polyhistidine-tagged versions of the same polypeptides immobilized to metal affinity columns and cooperative ligand-binding assays (Hill coefficient, nH \u3e 1 indicating PR-PR interaction). By all three assays, the LBD alone was not sufficient to mediate protein-protein interaction. However, the LBD did exhibit other properties ascribed to this domain, including binding to steroids with a relatively good affinity and specificity, ligand-induced conformational changes at the carboxyl terminus tail and binding of heat shock protein 90 and its dissociation in response to hormone. Thus, failure of the expressed LBD to mediate dimerization does not appear to be due to an extensively misfolded or unstable polypeptide. The minimal carboxyl-terminal fragment capable of mediating PR-PR interaction was the hLBD construct. However, by immobilized metal affinity chromatography assay, self-association of PR-A was 3.5-fold more efficient than that of either the DhLBD or hLBD constructs. An expressed amino-terminal domain (aa 165–535) lacking the DNA-binding domain, hinge, and LBD was found to physically associate with PR-A or with another amino-terminal fragment lacking the LBD, but retaining the DNA-binding domain. These results provide evidence for direct amino-terminal interactions in the more efficient PR-PR interaction exhibited by wild-type PR-A, as compared with DhLBD and hLBD constructs. The overall results of this paper are consistent with the conclusion that the carboxyl-terminal LBD is not sufficient for mediating PR dimerization and that multiple regions, including the hinge and amino-terminal sequences, contribute either directly or indirectly to homodimerization of PR

Crystal structure of Trypanosoma cruzi heme peroxidase and characterization of its substrate specificity and compound I intermediate

The protozoan parasite Trypanosoma cruzi is the causative agent of American trypanosomiasis, otherwise known as Chagas disease. To survive in the host, the T. cruzi parasite needs antioxidant defense systems. One of these is a hybrid heme peroxidase, the T. cruzi ascorbate peroxidase-cytochrome c peroxidase enzyme (TcAPx-CcP). TcAPx-CcP has high sequence identity to members of the class I peroxidase family, notably ascorbate peroxidase (APX) and cytochrome c peroxidase (CcP), as well as a mitochondrial peroxidase from Leishmania major (LmP). The aim of this work was to solve the structure and examine the reactivity of the TcAPx-CcP enzyme. Low temperature electron paramagnetic resonance spectra support the formation of an exchange-coupled [Fe(IV)=O Trp233•+] compound I radical species, analogous to that used in CcP and LmP. We demonstrate that TcAPx-CcP is similar in overall structure to APX and CcP, but there are differences in the substrate-binding regions. Furthermore, the electron transfer pathway from cytochrome c to the heme in CcP and LmP is preserved in the TcAPx-CcP structure. Integration of steady state kinetic experiments, molecular dynamic simulations, and bioinformatic analyses indicates that TcAPx-CcP preferentially oxidizes cytochrome c but is still competent for oxidization of ascorbate. The results reveal that TcAPx-CcP is a credible cytochrome c peroxidase, which can also bind and use ascorbate in host cells, where concentrations are in the millimolar range. Thus, kinetically and functionally TcAPx-CcP can be considered a hybrid peroxidase.Fil: Freeman, Samuel L.. University of Bristol; Reino UnidoFil: Skafar, Vera. Universidad de la República; UruguayFil: Kwon, Hanna. University of Leicester; Reino UnidoFil: Fielding, Alistair J.. Liverpool John Moores University; Reino UnidoFil: Moody, Peter C.E.. University of Leicester; Reino UnidoFil: Martínez, Alejandra. Universidad de la República; UruguayFil: Issoglio, Federico Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidade Nova de Lisboa; PortugalFil: Inchausti, Lucas. Universidad de la Republica; Uruguay. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Smircich, Pablo. Instituto de Investigaciones Biológicas "Clemente Estable"; Uruguay. Universidad de la Republica; UruguayFil: Zeida, Ari. Universidad de la Republica; UruguayFil: Piacenza, Lucía. Universidad de la Republica; UruguayFil: Radi, Rafael. Universidad de la Republica; UruguayFil: Raven, Emma L.. University of Bristol; Reino Unid

Changes in cholesterol homeostasis and acute phase response link pulmonary exposure to multi-walled carbon nanotubes to risk of cardiovascular disease

AbstractAdverse lung effects following pulmonary exposure to multi-walled carbon nanotubes (MWCNTs) are well documented in rodents. However, systemic effects are less understood. Epidemiological studies have shown increased cardiovascular disease risk after pulmonary exposure to airborne particles, which has led to concerns that inhalation exposure to MWCNTs might pose similar risks.We analyzed parameters related to cardiovascular disease, including plasma acute phase response (APR) proteins and plasma lipids, in female C57BL/6 mice exposed to a single intratracheal instillation of 0, 18, 54 or 162μg/mouse of small, entangled (CNTSmall, 0.8±0.1μm long) or large, thick MWCNTs (CNTLarge, 4±0.4μm long). Liver tissues and plasma were harvested 1, 3 and 28days post-exposure. In addition, global hepatic gene expression, hepatic cholesterol content and liver histology were used to assess hepatic effects.The two MWCNTs induced similar systemic responses despite their different physicochemical properties. APR proteins SAA3 and haptoglobin, plasma total cholesterol and low-density/very low-density lipoprotein were significantly increased following exposure to either MWCNTs. Plasma SAA3 levels correlated strongly with pulmonary Saa3 levels. Analysis of global gene expression revealed perturbation of the same biological processes and pathways in liver, including the HMG-CoA reductase pathway. Both MWCNTs induced similar histological hepatic changes, with a tendency towards greater response following CNTLarge exposure.Overall, we show that pulmonary exposure to two different MWCNTs induces similar systemic and hepatic responses, including changes in plasma APR, lipid composition, hepatic gene expression and liver morphology. The results link pulmonary exposure to MWCNTs with risk of cardiovascular disease

Migraine in women: the role of hormones and their impact on vascular diseases

Migraine is a predominantly female disorder. Menarche, menstruation, pregnancy, and menopause, and also the use of hormonal contraceptives and hormone replacement treatment may influence migraine occurrence. Migraine usually starts after menarche, occurs more frequently in the days just before or during menstruation, and ameliorates during pregnancy and menopause. Those variations are mediated by fluctuation of estrogen levels through their influence on cellular excitability or cerebral vasculature. Moreover, administration of exogenous hormones may cause worsening of migraine as may expose migrainous women to an increased risk of vascular disease. In fact, migraine with aura represents a risk factor for stroke, cardiac disease, and vascular mortality. Studies have shown that administration of combined oral contraceptives to migraineurs may further increase the risk for ischemic stroke. Consequently, in women suffering from migraine with aura caution should be deserved when prescribing combined oral contraceptives

Modulation of Glucocorticoid Hormone Receptor Levels in Chicken Lymphoid Tissue Following Treatment With Androgens in Vivo

Lymphatic tissues are highly sensitive to androgens and androgens are thought to contribute to sex differences in the immune response. In this study we have examined the effects of androgens on cytosolic glucocorticoid receptor levels in lymphoid tissues. The immature chick was chosen for our experimental model because it allows the separate evaluation of the bursa of Fabricius (primarily B-cells) compared to the thymus (primary T-cells). Treatment with dihydrotestosterone (a potent androgen in chicks) for 3-12 days in vivo reduced the cytosolic glucocorticoid (triamcinolone acetonide-[3H]) receptors in the bursa tissue to ∼ 42% of control levels after 5 days and ≤ 5% of control levels after 7 days of treatment. The chick thymus tissues were still ~ 92% of control triamcinolone acetonide receptor levels after 5 days of androgen treatments. However, the thymus levels had dropped to ≤ 5% of control values after 12 treatment days. Thus a difference in the rate of decrease in the bursa of Fabricius compared to the thymus was indicated. The blastogenesis index (BI), a measurement of the percentage of cells progressing through the cell cycle, was figured using fluorescent DNA staining with diamidino phenylindole followed by flow cytomctry analysis. After 3, 5, or 7 days of androgen treatment, the bursa of Fabricius from dihydrotestosterone treated chicks (2 mg/day/chick) had a mean BI = 11.17 (±3.07 SD) which was significantly lower than the bursa of Fabricius from control chicks which showed a mean BI = 27.33 (±3.42 SD). The thymus from dihydrotestosterone treated chicks had a mean BI = 19.57 (±2.19 SD) which was slightly but not significantly higher than the control thymus BI = 17.38 (±0.89 SD). In summary, androgen treatment in vivo induced a decrease in the cytosolic glucocorticoid hormone receptor levels in both the chick thymus and bursa of Fabricius tissues while decreasing the blastogenesis index in the bursa cells but not in the thymus cells