4,291 research outputs found
The Development of Values Education Under the Integrated Learning Subject in the Philippines: Islamic Concepts and Peace Building
This research on the Philippine values education clarifies how much their understandings on values have been diversified, especially between Christians and Muslims
Self-affinities of Folds and Incomplete Similarity
A method to analyze self-affinities is introduced, andapplied to the large scale fold geometries of the Quaternary andTertiary in the inner belt of the Northeast Honshu Arc. Based onthis analysis, their geometries are found to be self-affine and canbe differently scaled in different directions. We recognize the selfaffinitiesfor the amplitude and the wavelength of folds, anddiscover a crossover from local to global altitude (vertical)variation of the geometries of folds in the Northeast Honshu Arc.Buckingham's Pi-theorem has been applied to similar systems ofinhomogeneous viscous Newtonian fluid under similar boundarycondition. However, Buckingham's Pi-theorem cannot give us theself-affinities of folds. A general renormalization-group argumentis proposed to the applicability of the similarity theory. By thisargument, we derive the self-affinities for the amplitude and thewavelength of folds as a parameter for the anisotropic stress field
Clostridium perfringensepsilon toxin H149A mutant as a platform for receptor binding studies
Clostridium perfringens epsilon toxin (Etx) is a pore-forming toxin responsible for a severe and rapidly fatal enterotoxemia of ruminants. The toxin is classified as a category B bioterrorism agent by the U.S. Government Centres for Disease Control and Prevention (CDC), making work with recombinant toxin difficult. To reduce the hazard posed by work with recombinant Etx, we have used a variant of Etx that contains a H149A mutation (Etx-H149A), previously reported to have reduced, but not abolished, toxicity. The three-dimensional structure of H149A prototoxin shows that the H149A mutation in domain III does not affect organisation of the putative receptor binding loops in domain I of the toxin. Surface exposed tyrosine residues in domain I of Etx-H149A (Y16, Y20, Y29, Y30, Y36 and Y196) were mutated to alanine and mutants Y30A and Y196A showed significantly reduced binding to MDCK.2 cells relative to Etx-H149A that correlated with their reduced cytotoxic activity. Thus, our study confirms the role of surface exposed tyrosine residues in domain I of Etx in binding to MDCK cells and the suitability of Etx-H149A for further receptor binding studies. In contrast, binding of all of the tyrosine mutants to ACHN cells was similar to that of Etx-H149A, suggesting that Etx can recognise different cell surface receptors. In support of this, the crystal structure of Etx-H149A identified a glycan (β-octyl-glucoside) binding site in domain III of Etx-H149A, which may be a second receptor binding site. These findings have important implications for developing strategies designed to neutralise toxin activity
Review of the Genus Andropogon (Poaceae: Andropogoneae) in America Based on Cytogenetic Studies
Andropogon is a pantropical grass genus comprising 100–120 species and found mainly in the grasslands of Africa and the Americas. In the new world the genus is represented by approximately sixty (diploids or hexaploids) species grouped in three sections. The hexaploid condition occurs only in the Americas and the full process of this origin is still uncertain, although cytogenetic analysis coupled with taxonomic evidence have provided strong support for new hypothesis. Stebbins proposed the first hypothesis suggesting that the origin of polyploidy in species of Andropogon in North America resulted from duplication of the genome of some diploid species, and then by intergeneric crosses with species of a related genus. Since then, numerous studies were performed to clarify the evolutionary history of the genus in America. In this paper, we present a review of cytogenetic studies in the American Andropogon species during the last four decades.Fil: Nagahama, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Norrmann, Guillermo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botanica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botanica del Nordeste; Argentin
Modeling the potential distribution of Valeriana carnosa Sm. in Argentinean Patagonia: A proposal for conservation and in situ cultivation considering climate change projections
Over recent years species distribution models have been used for the identification of suitable cultivation zones for native plant species. Valeriana carnosa is one of the most frequently used native plants in Patagonian popular medicine, its underground organs being obtained from natural populations. Considering the growing market demand, it is now necessary to design strategies for the cultivation and conservation of this valuable species. In this study, Ecological Niche Modeling (ENM) using the Maxent model was used to predict potential geographical distributions of V. carnosa under current and future climatic conditions and considering the projected climate changes for the next fifty years in Argentinean Patagonia. Results showed that by 2070 it is expected that 22 % of the area with climatic conditions suited to V. carnosa will be lost. Most of these areas lie in the steppe region, and the remaining geographic areas with suitable climatic conditions will be found mainly in the Cordillera and Pre-Cordillera regions. We identified five endangered V. carnosa populations in Patagonia. This study provides a novel tool for planning in situ cultivation of V. carnosa and preserving genetic material from endangered populations, considering the climate projections for the coming decades in Patagonia.Fil: Nagahama, Nicolas. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Sur. Estación Experimental Agropecuaria Esquel; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bonino, Marcelo Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin
Membrane-damaging action of Clostridium perfringens alpha-toxin on phospholipid liposomes
AbstractThe effect of Clostridium perfringens alpha-toxin on multilamellar liposomes prepared from various phospholipids and cholesterol was investigated. The toxin induced carboxyfluorescein leakage from liposomes composed of the choline-containing phospholipids such as egg-yolk phosphatidylcholine and bovine brain sphingomyelin in a dose-dependent manner, but did not induce leakage from those liposomes composed of bovine brain phosphatidylethanol amine, egg-yolk phosphatidylserine or phosphatidylglycerol. The toxin-induced carboxyfluorescein leakage from egg-yolk phosphatidylcholine liposomes was increased by addition of divalent cations. The toxin induced carboxyfluorescein release from liposomes composed of phosphatidylcholine containing unsaturated fatty acyl residues or shorter chain length saturated fatty acyl residues (12 or 14 carbon atoms), but did not induce such release from liposomes composed of phosphatidylcholine containing saturated fatty acyl residues of between 16 and 20 carbon atoms. Furthermore, the toxin-induced carboxyfluorescein release decreased with increasing chain length of the acyl residues of phosphatidylcholine used. The toxin bound to liposomes composed of phospholipids which are hydrolyzed by the toxin, but did not bind to those composed of phospholipids which are not attacked by the toxin. The toxin-induced carboxyfluorescein release from liposomes composed of dipalmitoleoyl-l-α-phosphatidyl-choline and cholesterol and the toxin binding to the liposomes decreased with decreasing cholesterol contents. These observations suggest that the specific binding site formed by the choline-containing phospholipids and cholesterol, and membrane fluidity in liposomes are essential for the membrane-damaging activity of alpha-toxin
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