16 research outputs found

    Roles of Semaphorins in Neurodegenerative Diseases

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    Semaphorins are secreted and transmembrane proteins that bind plexin/neuropilin or integrin receptors, providing paracrine axonal guidance signals and ultimately leading to a functional and developed neuronal network. Following semaphorin’s initial discovery, their relevance in the central nervous system (CNS) soon intrigued researchers about the possible links between semaphorins, their receptors and signaling mechanisms and different neurodegenerative diseases. Here, we explore the current knowledge of semaphorin’s function and signaling in Alzheimer’s disease (AD), Parkinson’s disease (PD), Charcot-Marie-Tooth disease (CMT), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and Human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP). We focus on the effects of the most known semaphorin subclasses 3A and 4D, yet extending our discussion to other semaphorins that have been found involved in specific neuropathologies and the potential effect of semaphorins modulating the immune system in disorders with inflammatory components. Molecular, cellular, and genetic evidences are reviewed, highlighting the relevance of semaphorins on each disease etiology, pathophysiology, and progression. The newly discovered semaphorin functions in neurological disorders even suggest alternative therapies that may be highly valuable in diseases that have no current cure

    Identification and subcellular localization of two isoenzymes of apyrase from Solanum tuberosum

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    Two forms of ATP-diphosphohydrolase were identified in Solanum tuberosum tuber var. Ultimus. Their hydrolytic activity ratios (ATPase/ADPase) were over 10 for form A and 1 for form B. In the potato tuber homogenate the hydrolytic activity ratio is 3.0, as a result of contributions of the two forms of apyrase. These two apyrases (A and B) were partially separated and the possibility that they are produced as an artifact by partial proteolysis or subunit aggregation was excluded. The subcellular localization of the Ultimus isoapyrases was studied by differential centrifugation. These enzymes are localized in distinct compartments. The high ratio enzyme (A) lies mainly in the soluble fraction, while the low ratio apyrase (B) is principally bound to membranes. The two isoapyrases differ greatly in their kinetic properties and pI, but only slightly in Mr. Both enzymes immunocross-react with antiapyrase Desirée, which is important for isoenzyme detection by the immunowestern blot. This is t

    ATP fosfonato y azul de cibacron unidos a poliextrano para purificar pirofosfohidrolasas

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    Apyrase activity and changes in metabolites during germination and tuberization of Solanum tuberosum

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    Levels of adenine nucleotides, inorganic phosphate, starch and apyrase were measured during the growth of Solanum tuberosum tuber. The data obtained from potatoes sown in summer were compared with the data already reported for tubers sown in winter. Two major differences were found between the sowings. The first leads us to conclude that tubers from the summer sowing mature 21 days before the winter one, because starch and inorganic phosphate reach constant values earlier. The second difference was found in apyrase activity, which in tubers from the summer sowing reached a maximum after 106 days, while in winter tubers its specific activity and amount increased continously until maturity. The same types of metabolites and apyrase activity were investigated in shoot and mother tuber during germination of potatoes. In the mother tuber the amounts of metabolites and enzyme activity remain almost constant except for starch which showed a tendency to decrease at the end of the period analy

    The effect of bivalent metal ions on ATPase-ADPase activities of apyrase from Solanum tuberosum

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    The purpose of this study was the elucidation of the possible importance of bivalent metal ions in controlling the activity of apyrase (ATP: diphosphohydrolase EC 3.6.1.5) purified from tubers of Solanum tuberosum cv Desirée. Similarities between the Km and Vmm values for ADP and Ca2+ suggest that the true substrate of this enzyme is the metal ion-nueleotide complex. The association constant of the Ca-ADP complex was measured under the same conditions of pH and ionic strength as in the enzymatic assay system in order to calculate the true concentration of this complex. In contrast, [Mn(H2O)6]2+ spin resonance spectroscopy (ESR) showed that apyrase binds this paramagnetic metal ion in the absence of ATP or ADP. The spectrum of [Mn(H2O)6]2+ showed a transition at low field after the addition of apyrase. This result indicates that the binding of the enzyme produces a distortion in the electronic symmetry of [Mn(H2O)6]2+. Apyrase binds other bivalent cations because hysteretic behaviour i

    A comparative study of fish species identification by gel isoelectrofocusing, two-dimensional gel electrophoresis, and capillary zone electrophoresis

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    A comparative study of fish species identification was accomplished using three different electrophoretic techniques. Sarcoplasmic proteins were extracted from three related fish species and subjected to gel isoelectrofocusing (IEF), two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), and capillary zone electrophoresis (CZE). The fish species-Genypterus chilensis, Genypterus blacodes, and Genypterus maculatus-were from the Ophidiidae family. The three electrophoretic techniques provided suitable fish species identification. Nevertheless, CZE demonstrated several advantages over the other two conventional techniques. Some of the benefits include the use of small amounts of reagents; short separation times, permitting fast comparative analysis; data reproducibility; and ease with which the technique is performed

    Human T-Lymphotropic Virus Type 1 and 2 Seroprevalence among first-time blood donors in Chile, 2011-2013

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    Infection with human T-lymphotropic virus type 1/2 (HTLV-1/2) is a major health problem. HTLV-1/2 infection is endemic in Chile but representative donor prevalence data are lacking. Data on all blood donors in a large network of Chilean blood centers were examined during 2011-2013. Screening of HTLV-1/2 antibodies were measured by enzyme immunoassay (EIA) at all blood banks. Blood samples with anticoagulants from initially reactive blood donors were analyzed by serological confirmation tests (immunofluorescence or recombinant immunoblot) at the HTLV National Reference Laboratory of the Public Health Institute of Chile. Additionally, detection of HTLV-1 and HTLV-2 provirus in peripheral blood mononuclear cells (PBMCs) was performed in all blood donors as confirmatory test. Prevalence rates were calculated. Among 694,016 donors, 706 were seropositive for HTLV-1 (prevalence, 1.02 cases per 1,000; 95% confidence interval [CI], 0.94-1.09), and 97 were seropositive for HTLV-2 (prevalence, 0.14 cases per 1,000; 95%CI, 0.11-0.17). Prevalence of HTLV-1 differed considerably by region, from 0.51 to 1.69 per 1,000. Prevalence of HTLV-2 was similar across the country (0.12-0.16). HTLV-1 prevalence was associated with female sex, older age, and residence in the north of Chile. HTVL-2 prevalence was associated with older age. The HTLV-1 prevalence among Chilean blood donors was relatively high and could be reduced by improving donor recruitment and selection in high prevalence areas. Blood center data may contribute to surveillance for HTLV-1 and HTLV-2 infections
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