Vascular reactivity in hypertension: Altered effect of ouabain

Summary Ouabain inhibits the relaxing effect of Ca²⁺ (but not of Mn²⁺) on contractile responses in tail artery strips isolated from spontaneously hypertensive and normotensive rats. The magnitude of ouabain inhibition was greater in vascular strips from hypertensive rats suggesting a significant difference in basic membrane function in hypertensive vascular smooth muscle.These studies were supported by National Heart, Lung, and Blood Institute grants HL-03765 and HL-18575-02-03. R.C. Webb is a Postdoctoral Research Fellow of the Michigan Heart Association.     

The effect of Emetine on macromolecular synthesis in synchronizedTetrahymena pyriformis

Zusammenfassung Emetin hemmt die synchronisierte Teilung vonTetrahymena pyriformis, verhindert die rasche Aufnahme von Aminosäuren und verursacht offenbar eine Zellteilungshemmung.

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This work was supported in part by grants from the Hawaii Heart Association and the Julius and Dorothy Fried Foundation.     

Insulin stimulation of glucose and amino acid transport in mouse fibroblasts with elevated membrane microviscosity

Summary Basal and insulin-stimulated transport of 2-deoxy glucose and of -aminoisobutyric acid in mouse 3T3 fibroblasts were modulated by increasing the lipid microviscosity of the cell plasma membrane. The kinetics indicate that the insulin effect is induced either by recruitment of new transport carriers or by reduction of the translocation activation energy.This investigation was supported by grant No.5-R01-CA-27471-02, awarded by the National Cancer Institute, Department of Health, Education and Welfare.     

Altered morphology and behaviour of kidney fibroblasts in vitro,following in vivo treatment of rats with a carcinogenic dose of dimethylnitrosamine

Zusammenfassung Eine Woche nach Behandlung mit Dimethylnitrosamin wurden an Nierenrindenzellen von Ratten Fibroblasten mit veränderter Morphologie und Verhalten festgestellt, welche sich zu mesenchymalen Nierentumoren entwickelten.     

A dynamic view of peptides and proteins in membranes

Biological membranes are highly dynamic supramolecular arrangements of lipids and proteins, which fulfill key cellular functions. Relatively few high-resolution membrane protein structures are known to date, although during recent years the structural databases have expanded at an accelerated pace. In some instances the structures of reaction intermediates provide a stroboscopic view on the conformational changes involved in protein function. Other biophysical approaches add dynamic aspects and allow one to investigate the interactions with the lipid bilayers. Membrane-active peptides fulfill many important functions in nature as they act as antimicrobials, channels, transporters or hormones, and their studies have much increased our understanding of polypeptide-membrane interactions. Interestingly several proteins have been identified that interact with the membrane as loose arrays of domains. Such conformations easily escape classical high-resolution structural analysis and the lessons learned from peptides may therefore be instructive for our understanding of the functioning of such membrane proteins. Received 11 March 2008; received after revision 2 May 2008; accepted 5 May 2008     

A simple method for reduction of non-specific fluorescence

Résumé Cette technique pour la réduction de la fluorescence non-spécifique utilise diverses méthodes communes en une série spéciale. Premièrement, les anticorps fluorescents sont adsorbés avec la poudre du foie. Suivant la centrifugation, une colonne de Séphadex-25 est utilisée pour séparer la fluorescéine libre. La méthode contraire donne une fluorescence non-spécifique qui ressemble à celle obtenue avec une seule adsorption ou Séphadex filtration.     

Fluorometric study of interaction between ACTH fragments and bovine adrenocortical membranes

Summary Corticotropin_1–24 and [Gly¹]corticotropin_1–18 amide increased the fluorescence of 1-anilinonaphthalene-8-sulfonate which bound to the bovine adrenocortical membranes. The two ACTH fragments interacted with the protein of the membranes and increased the net positive charge of the membranes.We thank Prof. Dr.M. Kikuno for his stimulating criticism. This work was partly supported by a grant from Keio University School of Medicine.