Beyond a Dichotomy of Perspectives: Understanding Religion on the Basis of Paul Natorp’s Logic of Boundary

Based on Paul Natorp’s (1854–1924) late post-Neo-Kantian “Logic of Boundary” (German: “Grenzlogik”) I will offer a methodically controlled, non-reductionist and equally anti-essentialist reconstruction of the notion of religion. The pre-eminent objective of this reconstructive work is to overcome the well-known epistemological as well as methodological problem of a dichotomy between inside and outside perspectives on the subject of religion. Differently put, the objective consists in an attempt to demonstrate that there actually is “reason in religion” that is intellectually accessible for academic knowledge production. Following Natorp’s splendid formulation I will argue that religion operates neither ‘within’ nor ‘beyond’ the ‘boundary of humanity’ but exactly on [or ‘in’] this boundary. More precisely, I will explicate that religious praxis (including its specific production of knowledge) from Natorp’s standpoint can be understood as the performative realization, and habitual embodiment of the (contextually concrete) boundary of humanity or human reason itself. Due to its principial self-referentiality this boundary carries the crucial sense of a first and last positive and, therefore, both in theoretical terms definitive and in practical terms eminently instructive notion of boundary with no outside. This paradoxically all-enclosing, positive boundary, while explicitly including life’s inevitable negativity but, nonetheless, able to ideally sublate it, is the reason why the practice of religion, as empirical evidence unmistakably documents, can provide an incommensurably fulfilling, significant and meaningful closure with regards to the innermost self-perception of its practitioners (concerning their self-determination or agency)

Characterization and histochemical localization of the rat intestinal Na⁺-D-glucose cotransporter by monoclonal antibodies

The localization of the Na+-D-glucose cotransporter in rat small intestine was investigated with four monoclonal antibodies which were raised against porcine renal brush-border membrane proteins. The antibodies alter high affinity phlorizin binding or Na+ gradient-dependent D-glucose uptake in kidney and intestine. In both organs, the antibodies react with polypeptides with apparent molecular weights of 75,000 and 47,000. In pig kidney, these polypeptides were identified as components of the Na+-D-glucose cotransporter (Koepsell, H., K. Korn, A. Raszeja-Specht, S. Bernotat-Danielowski, D. Ollig, J. Biol. Chem. 263, 18419-18429 (1988)). The electron microscopic localization of antibody binding was investigated by immunogold labeling of ultrathin plastic sections. In villi and crypts of duodenum, jejunum and ileum the antibodies bound specifically to brush-border membranes of enterocytes and did not react with the basolateral membranes. The density of antigenic sites in brush-border membranes was highest in jejunum, intermediate in ileum and lowest in duodenum. On the tip, the middle and the basis of the villi the density of antigenic sites was similar. The data demonstrate homologous Na+-D-glucose cotransporters in kidney and intestine. They suggest that during maturation of the enterocytes when the total area of brush-border membrane increases, the concentration of the Na+-D-glucose cotransporter in the brush-border membrane remains constant. However, we found that different segments of small intestine not only contain different surface areas of the transporter-containing brush-border membrane per intestinal length but also different densities of the transporter within the brush-border membrane

Reconstitution and partial purification of several Na⁺ cotransport systems from renal brush-border membranes. Properties of the L-glutamate transporter in proteoliposomes

Brush-border membranes of renal proximal tubules were solubilized with deoxycholate and some proteins were separated and incorporated into proteoliposomes by a reconstitution procedure which was analyzed in detail. The proteoliposomes contained mainly polypeptides with molecular weights of 152,000, 94,000, and 52,000, each of which could be separated further into homologous polypeptides with different isoelectric points. In the proteoliposomes, Na+ cotransport systems for D-glucose, acidic and neutral amino acids, and mono- and dicarboxylic acids were demonstrated by showing that due to an inwardly directed Na+ gradient the substrate concentrations in the proteoliposomes increased significantly over their respective equilibrium values. Using inhibition experiments, selectivity of the different transporters could be demonstrated. Studying the reconstituted L-glutamate transporter in detail, countertransport of L-glutamate and K+ was shown (i) at Na+ equilibrium the intraliposomal L-glutamate concentration increased significantly over the equilibrium value if an outside-directed K+ gradient was applied; (ii) Rb+ influx was significantly stimulated by the outflux of L-glutamate. By applying a K+ diffusion potential across the liposomal membrane by addition of valinomycin it could be shown that during L-glutamate transport in the presence of Na+ and K+ positive charge is transferred together with L-glutamate and Na+. The apparent Km value of L-glutamate uptake driven by concentration differences of 89 mM Na+ (out greater than in) and 89 mM K+ (in greater than out) was 26.3 +/- 1.3 microM. The Vmax value of 70.2 +/- 2.3 pmol X mg of protein-1 X S-1 was half the value measured in intact membranes

Post-translational mechanisms of zinc signalling in cancer

Three groups of proteins are actively involved in the control of intracellular zinc, consisting of ZIP channels (SLC39A), ZnT transporters (SLC30A), and metallothioneins. Malfunctions of many zinc transport proteins, especially those belonging to the ZIP family which increase cytosolic zinc availability, have been associated with cancer. Importantly, post-translational modifications have been reported to play an increasing role in the functional control of ZIP channels. In this chapter, we therefore detail the established role of zinc signalling in cancer, with an emphasis on breast cancer, as well as demonstrate effects of post-translational modifications by phosphorylation and proteolytic cleavage