Rapid preparation of pure chlorophyll a

Summary Very pure chlorophyll a has been obtained from blue-green algae by a simple precipitation procedure. Its purity is at least equal to that of chlorophyll a obtained from spinach by conventional chromatography.Acknowledgments. This work was supported by the Fonds zur Förderung der wissenschaftlichen Forschung of the Republic of Austria. We thank Dr H. Springer-Lederer for helpful comments and Prof. E. Broda for his interest.     

On the preparation of specimens for autoradiography

Riassunto Viene proposto un nuovo metodo tecnico che consente di preparare autoradiografie di preparati istologici già colorati, con la sovrapposizione al preparato istologico di un sottile strato di materiale impermeabile, senza alterazione delle possibilità di localizzazione del materiale radioattivo nel preparato istologico stesso.     

On the electrophoretic properties of a purified enterogastrone preparation

Zusammenfassung 1. Es wird ein Extrakt von Schweinedarm (Enterogastron), der die durch Histamin erzeugte Magensekretion herabsetzt, elektrophoretisch untersucht.2. Die aktive Enterogastronfraktion scheint keine elektrophoretische Beweglichkeit zu besitzen.3. Enterogastron ist wahrscheinlich keine proteinähnliche Substanz.4. Die Resultate werden besprochen und zu früheren Untersuchungen über die Chemie des Enterogastrons in Beziehung gesetzt.     

Fixation of elementary nitrogen byNostoc punctiforme (Kütz.) Hariot andScytonema bohneri Schmidle in pure and unialgal cultures

Zusammenfassung Während Stickstoffixierung durch viele Blaualgen bekannt ist, wird diese Fähigkeit vonScytonema bohnert hier zum erstenmal gemeldet. BeiNostoc functiforme erreicht die N-Fixierung höhere Werte als bisher von irgendeiner Blaualge bekannt war und ausserdem zeigt sich das bereits bekannte Phänomen, dass kontaminierende Bakterien den Ertrag an gebundenem Stickstoff erhöhen können.     

Biological activities of pure prostaglandins

Prostaglandins, the hydroxy unsaturated C20 fatty acids, are found throughout the body and have an equally wide range of biological activities. Prostaglandins are known to: 1) stimulate uterine contraction; 2) inhibit spontaneous contraction of the rabbit uterus; 3) inhibit the respiratory smooth muscle of different animals; 4) lower systemic arterial blood pressure when injected intravenously; 5) stimulate contractions in isolateral segments of intestinal smooth muscle of most species investigated; 6) produce transient sedation when intravenously injected in cats, and 7) inhibit lipolysis induced by catechal amines, corticotrophin, glucagon and thyroid stimulating hormone. The inhibitory and excitatory effects of prostaglandins may each have a physiological importance at different sites. Current state of knowledge of the distribution, metabolism and actions of the prostaglandins is still fragmentary. The functional significance of the prostaglandins is yet to be determined.     

Acid-base equilibrium in the heart-lung preparation

Résumé Etude de l'équilibre acide-basique de la préparation cur-poumon de l'étourneau, réalisée avec la technique habituelle et les moyens de corriger les altérations constatées. La recherche des causes de ces altérations a permis de conclure que l'alcalose respiratoire est due à la ventilation dont on se sert habituellement, tandis que l'acidose métabolique est due à une production de métabolites acides déclanchés surtout par la saignée des animaux donneurs et par la glucolyse qui se produit à partir de l'extraction du sang et jusqu'au moment de son emploi dans la préparation.

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This work has been supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina.     

Vegetative propagation of the cactusMamillaria woodsii craig through tissue cultures

Summary A new method of clonal multiplication is described in a representative from the Cactaceae family, which offers wide experimental and horticultural applications.     

Cholinesterase in the atherosclerotic intima and in fibroblast cultures

Summary Cholinesterase activity was present in the atheromatous plaque of the rabbit's atherosclerotic aorta. Cholinesterase activity was significantly increased in rat fibroblast cultures grown in the presence of hypercholesterolemic serum. Cholesterol ester synthesis in these cultures was inhibited by neostigmine, a cholinesterase inhibitor.Acknowledgments. We thank Patricia Fontaine for technical assistance and Patricia Candow and Barbara English for secretarial help. This work was supported by a grant from the Canadian Heart Foundation. Part of this work was presented at 1977 annual meeting of the Biochemical Society in London.