Zebrafish acid-sensing ion channel (ASIC) 4, characterization of homo- and heteromeric channels, and identification of regions important for activation by H+

There are four genes for acid-sensing ion channels (ASICs) in the genome of mammalian species. Whereas ASIC1 to ASIC3 form functional H+-gated Na+ channels, ASIC4 is not gated by H+, and its function is unknown. Zebrafish has two ASIC4 paralogs: zASIC4.1 and zASIC4.2. Whereas zASIC4.1 is gated by extracellular H+, zASIC4.2 is not. This differential response to H+ makes zASIC4 paralogs a good model to study the properties of this ion channel. In this study, we found that surface expression of homomeric zASIC4.2 is higher than that of zASIC4.1. Surface expression of zASIC4.1 was much increased by formation of heteromeric channels, suggesting that zASIC4.1 contributes to heteromeric ASICs in zebrafish neurons. Robust surface expression of H+-insensitive zASIC4.2 suggests that zASIC4.2 functions as a homomer and is gated by an as yet unknown stimulus, different from H+. Moreover, we identified a small region just distal to the first transmembrane domain that is crucial for the differential H+ response of the two paralogs. This post-TM1 domain may have a general role in gating of members of this gene family

Candidate amino acids involved in H+ gating of acid-sensing ion channel 1a

Acid-sensing ion channels are ligand-gated cation channels, gated by extracellular H+. H+ is the simplest ligand possible, and whereas for larger ligands that gate ion channels complex binding sites in the three-dimensional structure of the proteins have to be assumed, H+ could in principle gate a channel by titration of a single amino acid. Experimental evidence suggests a more complex situation, however. For example, it has been shown that extracellular Ca2+ ions compete with H+; probably Ca2+ ions bound to the extracellular loop of ASICs stabilize the closed state of the channel and have to be displaced before the channel can open. In such a scheme, amino acids contributing to Ca2+ binding would also be candidates contributing to H+ gating. In this study we systematically screened more than 40 conserved, charged amino acids in the extracellular region of ASIC1a for a possible contribution to H+ gating. We identified four amino acids where substitution strongly affects H+ gating: Glu63, His72/His73, and Asp78. These amino acids are highly conserved among H+-sensitive ASICs and are candidates for the “H+ sensor” of ASICs

Die gute Lehrerin, der gute Lehrer. Zur historischen Bedingtheit einer tragenden Idee in der Schweizer Lehrerinnen- und Lehrerbildung

Die Lehrerbildungsstätten in der Schweiz sind seit ihrer Gründung bemüht, \u27gute Lehrkräfte\u27 auszubilden. Die lehrerausbildenden Institutionen sahen sich allerdings erheblichen öffentlichen Pressionen ausgesetzt, wenn es um die Frage ging, was denn eine \u27gute Lehrkraft\u27 an Kenntnissen, Fertigkeiten und Fähigkeiten mitzubringen habe. Einer der Höhepunkte des langandauernden, mehr oder weniger intensiven Streits ist die Epoche der Reformpädagogik zu Beginn des 20. Jahrhunderts

Die Schule - Ein Blick zurück in die Zukunft

Der Blick in die Zukunft der Schule war immer und ist auch gegenwärtig schwierig. Die Perspektiven oszillieren zwischen einer weitgehend als defizitär beurteilten Gegenwart und einer als kaum befriedigend zu beschreibenden Zukunft der Schule als Bildungs- und Lerninstitution. Wie sieht die künftige Schule aus? Und: Inwieweit taugen Prognosen für den pädagogischen Bereich? (DIPF/Orig.

Das Bild der Lehrkraft und dessen Impulse für die Professionalisierung von Lehrerinnen und Lehrern

Zusammenfassung: In diesem Beitrag werden Bilder von Lehrkräften als Konstrukteeiner an Bildung und Schule interessierten Öffentlichkeit geschildert.Lehrerinnen- und Lehrerbilder werden interpretiert als produktive Anstöße zurReflexion darüber, was die Professionalisierung pädagogischen Handelns inSchule und Unterricht implizieren könnte, insbesondere, wenn es um die Eigenschaftenvon ‚guten Lehrkräften‘ und ‚schlechten Lehrkräften‘ geht

The spectacle of citizenship: Halftones, print media, and constructing Americanness, 1880--1940

Advances in photography and conceptions of national identity proceeded side by side during the nineteenth century. The introduction of halftone reproductions marks the beginning of an information revolution and is an important moment not only in media history, but in studies of nineteenth and twentieth century cultural history and studies of national identity. Visual representation of differences between people and places was one means by which people identified and validated Americans\u27 belonging because photographs were infused with authority: they seemed to be truthful, to provide infallible evidence of events and of people. as the nineteenth century gave way to the twentieth, and technological advances made the halftone process quick and inexpensive, men and women of the Gilded Age, Progressive Era, Jazz Age, and the Great Depression used photographs for visual storytelling in the pages of newspapers, books, journals, and magazines. Editors embraced the seeming realism of photography in their publications; halftones in print helped Americans see each other in new ways and themselves for the first time on a regular, mass-circulating basis.; The Spectacle of Citizenship examines how three publications and their strong-willed editors used halftones to display and distribute their views of nationhood and belonging in a period when the United States was undergoing significant changes as a consequence of industrialization, immigration, urbanization, and international military and economic crisis. Paul Kellogg, editor of Charities and the Commons, and his brood of social justice progressives used halftones to display and include/exclude immigrants, racial minorities, and workers belying reform-minded middle class Americans claims of sympathy, understanding, and acceptance and instead riddling the journal with images that construct a sense of belonging for white, middle class Americans by explicitly identifying who did and did not belong. Joseph Medill Patterson, blue-blooded founder the Daily News, took a British idea for photograph-based newspapers aimed at the working class and reinvented it as the nation\u27s first tabloid. The newspaper captured Jazz Age New York City with splashy photographs emphasizing crime, scandal, celebrity, politics, and world events and invented a vision of America rooted in popular culture, patriotism, and American values . Patterson\u27s newspaper reinforced the hegemony of white, upper and middle class Americans, but it did so with an acceptance of rapidly changing social and cultural values in the country and the recognition of the importance of the urban working class population. C.K. McClatchy, long-time editor and publisher of the Sacramento Bee, used photographs to reinforce the suffering and make morally-loaded pleas for federal help during the Great Depression, to demonstrate the success of New Deal Programs, and to recast almost all Californians, regardless of their origin, as representative of America and Americans. Yet McClatchy s inclusive vision was problematic: he remained fervently anticommunist; he continued to believe Asian Americans, particularly Japanese Americas, could not be assimilated; and he virtually ignored the plight of Mexican Americans in the pages of the Sacramento Bee during the Great Depression, despite the fact that they were a significant part of the state\u27s population.; The Spectacle of Citizenship is a study of the interplay of technology, society, and culture that offers a new understanding of how notions of national identity were understood, produced, and disseminated and consumed in the late nineteenth and early twentieth centuries. This study analyzes the importance innovative editors placed on visual representations while at the same time demonstrating the necessity of contemporary scholars\u27 understanding those images

Tobias Rülcker/Peter Kassner (Hrsg.): Peter Petersen: Antimoderne als Fortschritt. Erziehungswissenschaftliche Theorie und pädagogische Praxis vor den Herausforderungen der Zeit. Frankfurt a. M./Bern: Lang 1992 [...] [Sammelrezension]

Sammelrezension von: 1. Tobias Rülcker/Peter Kassner (Hrsg.): Peter Petersen: Antimoderne als Fortschritt. Erziehungswissenschaftliche Theorie und pädagogische Praxis vor den Herausforderungen der Zeit. Frankfurt a. M./Bern: Lang 1992. 345 S. 2. Hein Retter (Hrsg.): Jenaplan-Pädagogik als Chance. Kindgerechte Schulpraxis im Zeichen europäischer Verständigung. Bad Heilbrunn: Klinkhardt 1993. 258 S

Overdue: A policy analysis of college library operation programs

The problem was to identify and assess the policy basis for the universal policy of colleges to have library operation programs. Colleges are higher education institutions whose main business is the delivery of college education, undergraduate instruction, leading to baccalaureate degrees. The conventional wisdom--the explanation of policy basis given in the literature--is a construct here called the College Library Doctrine. According to it, there is a fundamental relationship between the library operation program and the delivery of college education, undergraduate instruction. This relationship is said to be the result of historical process.;The College Library Doctrine was analyzed using a forensic or investigative approach. This approach looked for consistency and/or contradiction, treating the literature as data or evidence.;As a result of the analysis it was found that the same data or evidence supports a quite different explanation of why colleges have library operation programs. This alternative explanation of policy basis has little to do with the delivery of college education, undergraduate instruction. The existence of this quite different alternative explanation raises a serious reasonable doubt over the existence of the fundamental relationship posited by the College Library Doctrine.;The unresolved doubt, along with the recurrence of the college library operation program in the arena of institutional reputation, in topics such as quality, image, and prestige--through such phenomena as accreditation, ratings, rankings, and media coverage--suggest a policy relocation of the college library operation program from its usual but problematic placement in the broad area of academic support, to a different venue, institutional support. Enhancement of institutional reputation is an important part of institutional support. In this relocation there would be a better fit between policy basis and policy; and there, accordingly, the institutional support benefit and potential of the library operation program might be maximized.;The Appendix recalls an early question of the analysis conceptualization and demonstrates that, whether or not the results and conclusions of the analysis itself are accepted, there are decisive flaws in attempts to prescribe college library program resource allocation on the basis of historical data

A Study of the Lichens at Rocky Branch Nature Preserve, Clark County, Illinois

In 1971, a graduate student at Eastern Illinois University, James E. Wiedman, studied the lichen flora of Rocky Branch Nature Preserve, Clark County, Illinois. During his study he collected, identified, and recorded a total of 64 lichen species. Since 1971, Rocky Branch Nature Preserve has experienced a dramatic increase in use by people and a concomittant decline in the quality of lichen habitats. In order to assess the decline of suitable lichen habitats and the reduction of lichen species a second study of the lichens at Rocky Branch Nature Preserve was undertaken. As part of this study, ten habitat sites were selected from which lichens were collected, identified, and recorded. Ten collecting trips were made and a total of 46 lichen species were collected. A comparison of lichens collected in 1971 and 1993 is included as are all possible explanations for the decline in lichen diversity over this twenty-two year period