Sociedad civil y cultura democrática : mensajes y paradojas

Reunión: Seminario Regional sobre las Organizaciones de la Sociedad Civil y la Construcción de una Cultura Democrática, 8-12 Agosto 1988, Villa de Leyva, CODue to copyright restrictions, this item cannot be share

Mixed-Disulfide Folding Intermediates between Thyroglobulin and Endoplasmic Reticulum Resident Oxidoreductases ERp57 and Protein Disulfide Isomerase

We present the first identification of transient folding intermediates of endogenous thyroglobulin (Tg; a large homodimeric secretory glycoprotein of thyrocytes), which include mixed disulfides with endogenous oxidoreductases servicing Tg folding needs. Formation of disulfide-linked Tg adducts with endoplasmic reticulum (ER) oxidoreductases begins cotranslationally. Inhibition of ER glucosidase activity blocked formation of a subgroup of Tg adducts containing ERp57 while causing increased Tg adduct formation with protein disulfide isomerase (PDI), delayed adduct resolution, perturbed oxidative folding of Tg monomers, impaired Tg dimerization, increased Tg association with BiP/GRP78 and GRP94, activation of the unfolded protein response, increased ER-associated degradation of a subpopulation of Tg, partial Tg escape from ER quality control with increased secretion of free monomers, and decreased overall Tg secretion. These data point towards mixed disulfides with the ERp57 oxidoreductase in conjunction with calreticulin/calnexin chaperones acting as normal early Tg folding intermediates that can be “substituted” by PDI adducts only at the expense of lower folding efficiency with resultant ER stress

On the Pedagogical Turn in Latin American Social Movements

The role of the pedagogical is increasingly important in the construction of new forms of anticapitalist politics in Latin America. This is evidenced by the centrality of popular education and other forms of struggle influenced by radical education philosophy and pedagogy, and by social movements in their construction of new forms of participatory politics and mass intellectuality. It is also evidenced in the creation of formal and informal educational programs, practices and projects that develop varieties of critical pedagogy and popular education with both organized and nonorganized marginalized and excluded communities. Such a multiplicity and plurality of practices challenge many of the taken for granted assumptions about the nature of revolutionary struggle and revolutionary subjects, and the meaning and objectives of such struggle. They suggest the need for self-reflection and renovation within Marxist political categories so that they can maintain their relevance and relationship with the popular struggles and subjects at the heart of the creation of multiple pathways to twenty-first-century socialism (21 cs) in the region

‘Semi-dwarf’ woolly mammoths from the East Siberian Sea coast, continental Russia

A pioneer comprehensive study of several diminutive last-generation woolly mammoth teeth (M3) found on the coast of the East Siberian Sea between the mouths of the Alazeya and Malaya Kuropatoch'ya rivers was conducted. Two teeth belonged to one individual. These teeth have a similar lamellar frequency and enamel thickness as teeth of Mammuthus primigenius Blumenbach. The molar crowns from the lower Alazeya region are similar in size to those of the small Late Pleistocene–Holocene mammoths from Wrangel Island. However, the number of plates (17–19, excluding talons) is much lower than that in the teeth of typical Late Pleistocene M. primigenius (23–25). The age data of the examined teeth are beyond the limits of the 14C dating method (>45 000 years BP). Nevertheless, palaeobotanical data allow correlation of the enclosing sediments with the warm Kazantsevo Interglacial (Eemian, MIS 5e) and reconstruction of the average annual temperature, which was warmer than present-day temperatures. These conditions are confirmed by the δ18O isotopes from the structurally bound carbonate in tooth enamel. The ancient landscape was wetter and more forested than modern landscapes. The diminution of M3 size and loss of posterior plates were a result of the overall decrease in body size, likely in response to landscape change and narrowing of resource space. Mammoths from the lower Alazeya region demonstrate a stage of significant size reduction, although the dwarfing was not finalized. Their teeth are the oldest amongst the small teeth found in west Beringia