Quaternary Organic Amines Inhibit Na,K Pump Current in a Voltage-dependent Manner: Direct Evidence of an Extracellular Access Channel in the Na,K-ATPase

The effects of organic quaternary amines, tetraethylammonium (TEA) chloride and benzyltriethylammonium (BTEA) chloride, on Na,K pump current were examined in rat cardiac myocytes superfused in extracellular Na+-free solutions and whole-cell voltage-clamped with patch electrodes containing a high Na+-salt solution. Extracellular application of these quaternary amines competitively inhibited extracellular K+ (K+o) activation of Na,K pump current; however, the concentration for half maximal inhibition of Na,K pump current at 0 mV (K0Q) by BTEA, 4.0 ± 0.3 mM, was much lower than the K0Q for TEA, 26.6 ± 0.7 mM. Even so, the fraction of the membrane electric field dissipated during K+o activation of Na,K pump current (λK), 39 ± 1%, was similar to λK determined in the presence of TEA (37 ± 2%) and BTEA (35 ± 2%), an indication that the membrane potential (VM) dependence for K+o activation of the Na,K pump current was unaffected by TEA and BTEA. TEA was found to inhibit the Na,K pump current in a VM-independent manner, i.e., inhibition of current dissipated 4 ± 2% of the membrane electric field. In contrast, BTEA dissipated 40 ± 5% of the membrane electric field during inhibition of Na,K pump current. Thus, BTEA inhibition of the Na,K-ATPase is VM-dependent. The competitive nature of inhibition as well as the similar fractions of the membrane electric field dissipated during K+o-dependent activation and BTEA-dependent inhibition of Na,K pump current suggest that BTEA inhibits the Na,K-ATPase at or very near the enzyme's K+o binding site(s) located in the membrane electric field. Given previous findings that organic quaternary amines are not occluded by the Na,K-ATPase, these data clearly demonstrate that an ion channel–like structure provides access to K+o binding sites in the enzyme

The mechanism and control of Jagged1 expression in Sertoli cells

AbstractThe regulation of Sertoli cells by some hormones and signaling factors is important for normal spermatogenesis. Notch signaling is considered to be necessary for normal spermatogenesis in mouse. In this study, we revealed two new facts about Sertoli cells by western blotting experiments on different types of primary cells and microdissected tubules. The first is that Sertoli cells express the Jagged1 ligand in mice testes. The second is that the expression level of Jagged1 oscillates in the seminiferous epithelial cycle. Therefore, we inferred that Jagged1 in Sertoli cells contributes to the Notch signaling involved in spermatogenesis. Furthermore, we examined the regulation of Jagged1 expression and found that Jagged1 expression was suppressed by cAMP signaling and was promoted by TNF-α signaling in Sertoli cells. When cAMP and TNF-α were simultaneously added to Sertoli cells, Jagged1 expression was suppressed. Therefore, cAMP signaling dominates Jagged1 expression over TNF-α signaling. These results suggest that cAMP signaling may cause the periodicity of Jagged1 expression in the seminiferous epithelial cycle, and controlling Jagged1 expression by adding TNF-α or cAMP may contribute to normal spermatogenesis in vitro

Sinistral En Echelon Folding of the Sambagawa Schists and Its Tectonic Implication

The folds of the Sambagawa schists, which were produced during the last phase (Hijikawa—Oboke phase = Dh phase) of their folding history, are developed as a series of sinistral en echelon upright folds with half wavelength of less than 20 Km (Hara et al.,1977,1992). The Dh phase folds in Shikoku are accompanied with two culminations, Oboke culmination and Nakashichiban culmination, placed near the MTL. Their movement picture during the formation process of such the Dh phase folds has been analyzed on the basis of orientation pattern of parasitic folds and quartz microtextures. It has been clarified that the Dh phase folds were produced by left—lateral shear under N —S compression, being accompanied by the southward tectonic emplacement of two rigid bodies which gave rise to the Oboke and Nakshichiban culminations. These bodies can be assumed to be granitic and/or high—temperature metamorphic rocks tectonically derived from the Kurosegawa—Koryoke continent, as judged from the seismic refraction data in the Oboke district after Ichikawa (1968)

Comparison of Various Serum Protein Values in the Japanese and the Japanese-Americans Resident in the United States

Measurements were made of various types of proteins, that is α1-antitrypsin, α1-acid glycoprotein, α2-HS glycoprotein, haptoglobin, α2-macroglobulin, transferrin, C3, IgG, IgA and lgM, in the serum of the Japanese-Americans living in Hawaii and the Japanese-Americans living in Los Angeles who are assumed to be genetically almost identical to the Japanese in Hiroshima Prefecture but are known to have a higher intake of animal fats but a lower intake of complex carbohydrates. These were compared with those of the Japanese in Hiroshima Prefecture. α2-macroglobulin values in serum of the male Japanese-Americans living in Hawaii of ages 30-39 years, 40-49 years, and 50-59 years were significantly lower than those of the residents in Hiroshima Prefecture, but no significant difference in these values could be observed between the Japanese-Americans living in Los Angeles and the Japanese in Hiroshima Prefecture. No significant difference could be observed in the values of other serum proteins in all age groups. These findings indicate that the difference in intake volume of animal fats and complex carbohydrates did not affect these serum protein values

Dental Calculus Stimulates Interleukin-1beta Secretion by Activating NLRP3 Inflammasome in Human and Mouse Phagocytes

Dental calculus is a mineralized deposit associated with periodontitis. The bacterial components contained in dental calculus can be recognized by host immune sensors, such as Toll-like receptors (TLRs), and induce transcription of proinflammatory cytokines, such as IL-1beta. Studies have shown that cellular uptake of crystalline particles may trigger NLRP3 inflammasome activation, leading to the cleavage of the IL-1beta precursor to its mature form. Phagocytosis of dental calculus in the periodontal pocket may therefore lead to the secretion of IL-1beta, promoting inflammatory responses in periodontal tissues. However, the capacity of dental calculus to induce IL-1beta secretion in human phagocytes has not been explored. To study this, we stimulated human polymorphonuclear leukocytes (PMNs) and peripheral blood mononuclear cells (PBMCs) with dental calculus collected from periodontitis patients, and measured IL-1beta secretion by ELISA. We found that calculus induced IL-1beta secretion in both human PMNs and PBMCs. Calculus also induced IL-1beta in macrophages from wild-type mice, but not in macrophages from NLRP3- and ASC-deficient mice, indicating the involvement of NLRP3 and ASC. IL-1beta induction was inhibited by polymyxin B, suggesting that LPS is one of the components of calculus that induces pro-IL-1beta transcription. To analyze the effect of the inorganic structure, we baked calculus at 250 degrees C for 1 h. This baked calculus failed to induce pro-IL-1beta transcription. However, it did induce IL-1beta secretion in lipid A-primed cells, indicating that the crystalline structure of calculus induces inflammasome activation. Furthermore, hydroxyapatite crystals, a component of dental calculus, induced IL-1beta in mouse macrophages, and baked calculus induced IL-1beta in lipid A-primed human PMNs and PBMCs. These results indicate that dental calculus stimulates IL-1beta secretion via NLRP3 inflammasome in human and mouse phagocytes, and that the crystalline structure has a partial role in the activation of NLRP3 inflammasome

Quantum transport in a normal metal/odd-frequency superconductor junction

Recent experimental results indicate the possible realization of a bulk odd-frequency superconducting state in the compounds CeCu$_2$Si$_2$, and CeRhIn$_5$. Motivated by this, we present a study of the quantum transport properties of a normal metal/odd-frequency superconductor junctions in a search for probes to unveil the odd-frequency symmetry. From the Eliashberg equations, we perform a quasiclassical approximation to account for the transport formalism of an odd-frequency superconductor with the Keldysh formalism. Specifically, we consider the tunneling charge conductance and tunneling thermal conductance. We find qualitatively distinct behaviour in the odd-frequency case as compared to the conventional even-frequency case, in both the electrical and thermal current. This serves as a useful tool to identify the possible existence of a bulk odd-frequency superconducting state.Comment: 7 pages, 3 figures. Accepted for publication in Physical Review