Acute effect of hypophysectomy on the natriuresis following saline infusion in dogs.

The natriuresis following an i.v. isotonic saline loading corresponding to 10% of body wt. was markedly decreased after acute hypophysectomy, due to lowered urinary sodium concentration, in anaesthetized dogs. A role of the pituitary in such a homeostatic natriuresis is suggested.     

Partial mitotic index and phase indices

Résumé Cet article propose l'emploi de l'index mitotique partiel et des index mitotiques des phases pour l'analyse cytologique quantitative des modifications apparaissant au cours du cycle de division cellulaire, et suggère une méthode rapide pour calculer tous les indices mentionnés.     

Lipolytic effect of insulin and other hormones in vitro in aortic tissue of experimental animals

Zusammenfassung In der Aortenwand von Ratten, Meerschweinchen, Kaninchen und Schweinen wird eine hormonempfindliche Lipase beschrieben, die in vitro durch Katecholamine, ACTH und Glucagon beeinflusst wird. Glucagonfreies Insulin wies eine deutliche lipolytische Wirkung auf und unterschied sich dadurch von der Wirkung im Fettgewebe.     

Scanning-autoradiography—a new method for the demonstration of membrane-surface-associated structures

Summary A method for the demonstration of membrane-localized markers and receptors is described which results from the combination of autoradiography and scanning electronmicroscopy.     

Influence of age on the renal renin response to a high salt intake in the rat

Summary Saline drinking combined with DOCA-treatment was found to decrease renal renin in weanlings at a higher rate than in adult rats, with a comparable saline consumption level. The decrease was not potentiated by uninephrectomy.     

AS-48 bacteriocin: close to perfection

Bacteriocin AS-48 is an intriguing molecule because of its unique structural characteristics, genetic regulation, broad activity spectrum, and potential biotechnological applications. It was the first reported circular bacteriocin and has been undoubtedly the best characterized for the last 25 years. Thus, AS-48 is the prototype of circular bacteriocins (class IV), for which the structure and genetic regulation have been elucidated. This review discusses the state-of-the-art in genetic engineering with regard to this circular protein, with the use of site-directed mutagenesis and circular permutation. Mutagenesis studies have been used to unravel the role of (a) different residues in the biological activity, underlining the relevance of several residues involved in membrane interaction and the low correlation between stability and activity and (b) three amino acids involved in maturation, providing information on the specificity of the leader peptidase and the circularization process itself. To investigate the role of circularity in the stability and biological properties of the enterocin AS-48, two different ways of linearization have been attempted: in vitro by limited proteolysis experiments and in vivo by circular permutation in the structural gene as-48A. The results summarized here show the significance of circularization on the secondary structure, potency and, especially, the stability of AS-48 and point as well to a putative role of the leader peptide as a protecting moiety in the pre-proprotein. Taken all together, the data available on circular bacteriocins support the idea that AS-48 has been engineered by nature to make a remarkably active and stable protein with a broad spectrum of activity.     

Detection and substitution-pattern determination of guanidines

Summary The guanidine function can be detected and its substitution pattern determined taking into account the¹H-NMR signals of the N–H and N–C–H groups. Satisfactory results were obtained with mono-to penta-substituted guanidines (as picrate salts).Part XX ofStudies on Plants; preceding part,R. A. Corral, O. O. Orazi andI. A. Benages, Tetrahedron29, 205 (1973).