Cloning and characterization of the ALG3 gene of Saccharomyces cerevisiae

The Saccharomyces cerevisiae alg3-1 mutant is descilbed as defective in the biosynthesis of dolichol-linked oligosaccharides (Huffaker and Robbins, Proc. Natl. Acad. Sci. USA, 80, 7466-7470, 1983). Man5GlcNAc2-PP-Dol accumulates in alg3 cells and Endo H resistant carbohydrates are transferred to protein by the oligosaccharyltransferase complex. In this study, we describe the cloning of the ALG3 locus by complementation of the temperature sensitive growth defect of the alg3 stt3 double mutant. The isolated ALG3 gene complements both the defect in the biosynthesis of lipidlinked oligosaccharides of the alg3-mutant and the underglycosylation of secretory proteins. The inactivation of the nonessential ALG3 gene results in the accumulation of lipid-linked Man5GlcNAc2 and protein-bound carbohydrates which are completely Endo H resistant. The ALG3 locus encodes a potential ER-transmembrane protein of 458 amino acids (53 kDa) with a C-terminal KKXX-retrieval sequenc

Isolation of the ALG6 locus of Saccharomyces cerevisiae required for glucosylation in the N-linked glycosylation pathway

N-Linked protein glycosylation in most eukaryotic cells initiates with the transfer of the oligosaccharide Glc3Man9GlcNAc2 from the lipid carrier dolichyl pyrophosphate to selected asparagine residues. In the yeast Saccharomyces cerevisiae, alg mutations which affect the assembly of the lipid-linked oligosaccharide at the membrane of the endoplasmic reticulum result in the accumulation of lipid-linked oligosaccharide intermediates and a hypoglycosylation of proteins. Exploiting the synthetic growth defect of alg mutations in combination with mutations affecting oligosaccharyl transferase activity (Stagljar et al., 1994), we have isolated the ALG6 locus. alg6 mutants accumulate lipid-linked Man9GlcNAc2, suggesting that this locus encodes an endoplasmic glucosyltransferase. Alg6p has sequence similarity to Alg8p, a protein required for glucosylation of Glc1Man9GlcNAc

Interview mit Dieter Hoffmann

Wie kann man einen historischen Blick auf das eigene Fach werfen? Diese Frage ist nicht einfach zu beantworten – will man einerseits nicht in einer Nabelschau und Hagiographie enden, andererseits aber auch keinen umfassenden Entwurf einer zukünftigen Historiographie vorlegen. Die hier in loser Folge publizierten Interviews mit bekannten Protagonist:innen der Berliner Wissenschaftsgeschichte von ca. 1970–1990 in West und Ost rücken die Geschichte des Faches deshalb in einem bestimmten Milieu in den Fokus und versuchen, die Historiographie jenseits einer Institutionen- oder Theoriegeschichte voranzutreiben. Welche Motivationen oder Probleme bewegten einzelne Wissenschaftler:innen, sich der Geschichte ihres Faches zu widmen oder sich etwa aus der Soziologie oder Philosophie in die Wissenschaftsgeschichte zu bewegen? Welche Ausbildungspraktiken existierten in diesem heterogenen, zwischen den Disziplinen angesiedelten Feld, welche Anregungen bezog man aus welchen Kontexten? Wie war Lehre strukturiert und welche Netzwerke bildeten sich mit der Zeit? Kurz: Mit welchem Interesse kam man zur Wissenschaftsgeschichte und was wurde daraus? Die Auswahl der Interviewees erfolgt ohne Anspruch auf Vollständigkeit oder Proporz; der Fragenkatalog der Interviews richtet sich individuell nach den Biographien und dem Werk und entfaltet sich oft spontan im Gespräch. Die Interviews wurden digital aufgezeichnet, transkribiert, der Schriftsprache angepasst, gegebenenfalls gekürzt, annotiert und von den Interviewees authentifiziert. Wir beabsichtigen mit dieser Serie von Interviews zunächst die Dokumentation rezenter Geschichte durch eine Oral History, die subjektive Wahrnehmungen und persönliche Erlebnisse einschließt. Auf diese Weise werden Segmente einer größtenteils ungeschriebenen Geschichte anhand von Biographien erfahrbar und damit auch einer weiteren kritischen Bearbeitung und Integration in ein Gesamtbild zugänglich. Da uns im Zuge der jeweiligen Vorbereitung und Durchführung, Transkription und Abstimmung der Interviews daran gelegen war, aus Sicht der Akteur:innen wichtige Sammelbände und Aufsätze, Monographien oder auch „graue Literatur“ zu erfassen, wird nebenbei eine kommentierte Bibliographie zur Geschichte der Wissenschaftsgeschichte entstehen. Unsere Hoffnung besteht darin, mittels dieser Sammlung mit Berlin einen fruchtbaren Raum und mit den siebziger und achtziger Jahren eine produktive Zeit des Faches jenseits von Reminiszenz oder Nostalgie zu erkunden – nicht zuletzt auch, um den Blick für gegenwärtige Herausforderungen des Faches zu schärfen.Peer Reviewe

The role of critical reflexivity in the professional development of professional developers: A co-autoethnographic exploration

This manuscript shares findings from a collaborative autoethnography project during which two classroom teachers worked together with university researchers to develop and facilitate science education professional development workshops for elementary teachers in Luxembourg. Grounded in critical theoretical perspectives, we undertook a process of collaborative autoethnography grounded in dialogue and reflection, to examine our own professional development in the process of facilitating the professional development of our colleagues. First, we elaborate the cultural and historical importance of this project in the context of teacher professional development in Luxembourg, an education system that operates from a national primary school curriculum, but in which instructional decisions are made by teachers. Next, we describe how critical methodologies allowed us to examine working within this system from each of our unique perspectives, while critically analyzing the process of engaging in professional development with teachers. We then elaborate the two main claims that emerged from our collective processes of reflection, dialogue, and action, namely that undergoing this critical process in parallel with supporting teacher professional development facilitated changes in our perspectives and our positions towards the national curricula, and that our multiple roles coupled with the process of reflection-dialogue-action mediated taking agency and the adaptation of primary science curricula

The Saccharomyces cerevisiae CWH8 gene is required for full levels of dolichol-linked oligosaccharides in the endoplasmic reticulum and for efficient N-glycosylation

The Saccharomyces cerevisiae mutant cwh8 was previously found to have an anomalous cell wall. Here we show that the cwh8 mutant has an N-glycosylation defect. We found that cwh8 cells were resistant to vanadate and sensitive to hygromycin B, and produced glycoforms of invertase and carboxypeptidase Y with a reduced number of N-chains. We have cloned the CWH8 gene. We found that it was nonessential and encoded a putative transmembrane protein of 239 amino acids. Comparison of the in vitro oligosaccharyl transferase activities of membrane preparations from wild type or cwh8Δ cells revealed no differences in enzyme kinetic properties indicating that the oligosaccharyl transferase complex of mutant cells was not affected. cwh8Δ cells also produced normal dolichols and dolichol-linked oligosaccharide intermediates including the full-length form Glc3Man9GlcNAc2. The level of dolichol-linked oligosaccharides in cwh8Δ cells was, however, reduced to about 20% of the wild type. We propose that inefficient N-glycosylation of secretory proteins in cwh8Δ cells is caused by an insufficient supply of dolichol-linked oligosaccharide substrat

The Nature of Notebooks: How Enlightenment Schoolchildren Transformed the Tabula Rasa

John Locke's comparison of the mind to a blank piece of paper, the tabula rasa, was one of the most recognizable metaphors of the British Enlightenment. Though scholars embrace its impact on the arts, humanities, natural sciences, and social sciences, they seldom consider why the metaphor was so successful. Concentrating on the notebooks made and used by the schoolchildren of Enlightenment Scotland, this essay contends that the answer lies in the material and visual conditions that gave rise to the metaphor's usage. By the time students had finished school, they had learned to conceptualize the pages, the script, and the figures of their notebooks as indispensable learning tools that could be manipulated by scores of adaptable folding, writing, and drawing techniques. In this article, I reveal that historicizing the epistemology and manipulability of student manuscript culture makes it possible to see that the success of Locke's metaphor was founded on its appeal to everyday note-keeping activities performed by British schoolchildren