Export by red blood cells of nitric oxide bioactivity

Previous studies support a model in which the physiological O2 gradient is transduced by haemoglobin into the coordinate release from red blood cells of O2 and nitric oxide (NO)-derived vasoactivity to optimize oxygen delivery in the arterial periphery. But whereas both O2 and NO diffuse into red blood cells, only O2 can diffuse out. Thus, for the dilation of blood vessels by red blood cells, there must be a mechanism to export NO-related vasoactivity, and current models of NO-mediated intercellular communication should be revised. Here we show that in human erythrocytes haemoglobin-derived S-nitrosothiol (SNO), generated from imported NO, is associated predominantly with the red blood cell membrane, and principally with cysteine residues in the haemoglobin-binding cytoplasmic domain of the anion exchanger AE1. Interaction with AE1 promotes the deoxygenated structure in SNO-haemoglobin, which subserves NO group transfer to the membrane. Furthermore, we show that vasodilatory activity is released from this membrane precinct by deoxygenation. Thus, the oxygen-regulated cellular mechanism that couples the synthesis and export of haemoglobin-derived NO bioactivity operates, at least in part, through formation of AE1-SNO at the membrane-cytosol interface.     

Histidine phosphorylation and phosphoryl group transfer in bacterial chemotaxis

A cascade of protein phosphorylation, initiated by autophosphorylation of the CheA protein, may be important in the signal transduction pathway of bacterial chemotaxis. A proteolytic fragment of CheA cannot autophosphorylate, but can still transfer phosphate to proteins that generate excitation and adaptation signals. The site of CheA phosphorylation is His 48; mutants altered at this position are non-chemotactic. Similar mechanisms of transient protein phosphorylation and phosphoryl group transfer seem to be involved in processing sensory data and in activating specific gene expression.     

Proestrous gonadotropin levels in thyroparathyroidectomized female rats

Summary Intact and TPTx animals showed the expected afternoon increase in serum LH, FSH and prolactin levels. But the afternoon increase in serum LH levels in TPTx rats was less than that observed for intact animals (p<0.01). Neither serum prolactin nor FSH levels were altered by TPTx.The excellent technical and secretarial assistance ofS. Hemelt andD. Landman is gratefully acknowledged.     

Comparative dominant lethal studies with phenylbutazone,thio-TEPA and MMS in the mouse

Zusammenfassung Im Gegensatz zu Thio-TEPA (N, N, N-Triaethylen-thiophosphoramid) und MMS (Methansulfonsäuremethylester) führten i.p. Dosen von Phenylbutazon (50 und 100 mg/kg) bei der Maus, unter Berücksichtigung von post- und prae-implantativen Gestationsstadien, zu keinen genetischen Effekten im Sinne der Induktion von dominanten Letalfaktoren.     

Hypolipidaemic properties of a new tetralin derivative (CIBA 13,437-Su)

Zusammenfassung 2-Methyl-2-[p-(1,2,3,4-tetrahydro-1-naphthyl)-phenoxy]-propion-säure (CIBA 13,437-Su)stellt ein oral aktives Tetralin-Derivat dar, welches ausgeprägte Blutlipid-senkende Eigenschaften besitzt. Die hypolipidaemische Wirkung wurde bei mehreren Spezies untersucht und umfasste sowohl Cholesterin wie Glyzeride.     

Organtypische und phasenspezifische Verteilung ungesättigter Lipoide im Schwanz der Larve vonXenopus laevis

Summary Barrollier's method for unsaturated fatty acids (u. f. a.) in paper chromatograms has been adapted for cytochemical detection of u. f. a. in the tails ofXenopus-larvae. A specific pattern in the different organs was found. It was further shown that the content in u. f. a. changes quickly, apparently indicating rapid changes in physiological conditions during growth and regeneration.     

Modelle für Reaktionen zwischen organischen und mineralischen Substanzen im Boden

Summary Low molecular siloxanes, silicagel, aluminium oxide, permutite, and perlite were dissolved by ammoniacal catechol solution. Silicagel was also dissolved by othero-diphenols. Low molecular silicon organic ester or complex compounds were crystallised from the reaction products of silicagel with catechol and 2,3-naphthalenediol. On orthoclase an insoluble brown cover was formed. The reaction ofo-diphenols with silicates may be important in soil formation.