Abbau von Quarz mit Brenzkatechin

Summary Fine divided HF-etched quartz was dissolved in a 0.2M solution of pyrocatechol at pH 9.6. Between 17 and 40 °C the dissolution rate (v _s ) follows the equation: logv _s =0.0295 T-20.87 At 25 °Cv _s amounts to 0.8 · 10^–12 g cm^–2 sec^–1. With several phenols the dissolution rate of quartz decreases in the order: pyrocatechol > pyrogallol > 2, 3-dihydroxynaphthalene.     

Beeinflussung der ATPase aminspeichernder Granula von Nebennierenmark und Milznerven durch Thallium

Summary ATPases of the amine storing granules from bovine adrenal medulla and splenic nerves are inhibited by Tl⁺⁺⁺ 3×10^–5 and 5×10^–6 M, respectively. Tl⁺ up to 10^–3 M is ineffective. By T1⁺⁺⁺ in concentrations of 10^–4 M or more, proteins are precipitated, so that the enzyme inhibiton by these concentrations is unspecific. If T1⁺ is oxidized to Tl⁺⁺⁺ in the organism, the inhibition of granular ATPase may be responsible for the alterations of the catecholamine metabolism observed in thallium intoxication.     

Zum Nachweis von Aminen im 10−10-Mol-Maßstab. Trennung von 1-Dimethylamino-naphthalin-5-sulfonsäure-amiden auf Dünnschichtchromatogrammen

Summary For the sensitive determination of amines their 1-dimethyl-amino-naphthalene-5-sulphonyl derivatives were separated in two-dimensional thin-layer chromatograms. 10^–10–10^–11 mole per amine can be detected, when the fluorescence of the DANSyl-compounds is excited by the 365 mµ Hg line.     

Zum Reaktionsmechanismus von Oxydasen

Summary The reactivity of copper(I)-complexes towards molecular oxygen in relation to some copper containing enzymes has been studied. The oxydation of simple amine-complexes proceeds at a rate of about 10³–10⁴ Mol^–1 Lt Min^–1. Replacing the amine by amides and peptides has a strong retarding effect. A copper(I)-cysteine complex exhibits the interesting property of adding O₂ reversibly.     

Zur Frage der Wirkung von DTPA auf Säugerchromosomen in vitro

Summary The influence of DTPA on the chromosome aberration rate of Chinese hamster cells in culture was studied. No increase of the aberration rate was observed after treatment with 10^–2 and 10^–3 M concentrations.     

Zur Wirkung von Zn++ auf die Nukleinsäurebiosynthese von Aszites-Tumorzellen

Summary Ascites tumour cells have been employed to study the reactivity of Zn⁺⁺ on nucleic acid biosynthesis. 10^–4 M Zn⁺⁺ caused a selective inhibition of DNA synthesis of intact cells. The rate of RNA- and protein-biosynthesis, however, remained unchanged. The activity of DNA polymerase as well as DNA dependent RNA polymerase was strongly affected by Zn⁺⁺ in vitro.     

Interaction du 2,4-dichlorophénol et de l'eau oxygénée dans la destruction enzymatique de l'acideβ-indolylacétique

Summary DCP increases IAA destruction by bothLens andPhaseolus root breis. H₂O₂ inhibits catabolism byLens extracts but activates it whenPhaseolus is used, mainly when roots are cultivated in the dark and contain inhibitors of IAA destruction. DCP 1·10^–3 M and H₂O₂ 1·10^–4 or 1·10^–3 volume forLens and DCP 1·10^–4 M and H₂O₂ 1·10^–3 volume forPhaseolus nullify auxin catabolism.     

Intraaxonaler Transport von 3H-Uridin-Verbindungen im Tractus opticus von Teleosteern

Summary After application of 3-H uridine to one eye-ball, an intraaxonal flow of RNA (1–3 mm/d) and low-molecular uridine-compounds (30–50 mm/d) has been demonstrated in the optic tract ofScardinius erythrophtalmus andCarassius carassius (Teleostei).     

Effect of sulpiride on oxygen uptake by rat's brain tissue in vitro

Resumen El Sulpiride in vitro a la concentración de 1×10^–2 M disminuye el consumo de Oxígeno en cortes de cerebro de rata. El exceso de potasio o ausencia de calcio en el medio de incubación, no modifican este efecto. En homogeneizado de cerebro total, unicamente a la concentración de 1×10^–2 M deprime el consumo de oxígeno. A las concentraciones 1×10^–3 y 1×10^–4 M no modifica el consumo de oxígeno en cortes ni homogeneizados de cerebro.     

The effect of perchlorate ion and some pharmacological agents on the sensitivity of the frog (Rana pipiens) rectus abdominis to acetylcholine

Zusammenfassung Die Reaktion des mit Eserin vorbehandelten musculus rectus abdominis des Frosches auf Acetylcholin liess sich durch Oxotremorin (2.0·10^–5 M), Arecolin (2.0·10^–5M), Aceclidin (1.0·10^–4 M) und Carbachol (2.0·10^–7 M) verstärken, während Atropin (1.0·10^–5 M) hemmend wirkte. Perchlorationen in Konzentrationen über 2 · 10^–4 M sensibilisierten den Froschmuskel erheblich und reduzierten die Grenzdosis, bei der eine Potenzierung durch Substanzen mit muskarinähnlicher Wirkung beobachtet wird. Alle beschriebenen Reaktionen liessen sich durch Gehirnextrakte verstärken, in denen zuvor Acetylcholin durch Kochen in alkalischer Lösung zerstört worden war.

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This work was supported by NIH Grants No. NB 03007 and No. 5-F1-GM-22,905.     

Kinetik der hepatischen Farbstoffaufnahme von Indocyaningrün. Einfluss von Bilirubin und Natriumglykocholat

Summary Kinetics of hepatic uptake of indocyanine green, a dye which is used for evaluation of liver function, were studied in the rat. The results indicate that the relationship between ICG-dose and initial hepatic dye uptake obeys Michaelis-Menten kinetics suggesting an interaction of the dye with a carrier or fixed site in the liver cell. Thus it was possible to calculate maximum ICG-uptake (v _max ) and the Michaelis constant (K _m ) of this transport system from several submaximal values.v _max was 7.65 (6-06-9.65)²² mg per 100 g liver/min and K _m 0.56 (0.31–0.81)²². Under the influence of substances which inhibit the elimination of dyes by the liver the parametersv _max and K _m showed changes which allowed characterization of the type of inhibition. While sodium glycocholate had no influence on maximum hepatic ICG-uptake and the Michaelis constant bilirubin caused a significant increase of K _m to 1.29 (0.68–1.90)²² without significantly changingv _max . These data suggest that bilirubin interferes with hepatic uptake of indocyanine green by competitive inhibition and that uptake of bile acids is dependent on a different mechanism.     

Variations de l'activité des auxines-oxydases dans les racines duLens

Summary 2, 4-dichlorophenol (DCP), 2, 4-dinitrophenol (DNP) and 2, 4-dinitro-o-cresol (DNC) applied at a concentration of 1.10^–7 to 1.10^–3 M, produce a dramatic increase in IAA-oxidase activity in young cells ofLens root. IAA destruction by breis from root tissues was inhibited by Mn⁺⁺ ion at low concentrations of DCP (1·10^– to 1.10^–7 M), but was enhanced by Mn⁺⁺ ion at higher (1.10^–5 to 1.10^–3 M) DCP levels.

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Ce travail a pu être entreprise grâce à l'appui duFonds national suisse pour la Recherche scientifique.     

Triazine nucleic acid interrelationship inEscherichia coli 15 arg− t − u −

Zusammenfassung Mit Hilfe von 5-Bromuracil wurde die prinzipielle Fähigkeit vonEscherichia coli 15 arg^– t ^– u ^–, Basenanaloge des Pyrimidins für die Synthese ihrer Nukleinsäuren zu verwenden, gezeigt. Ein Einbau der Triazinverbindungen Atrazin und Prometryn in die Nukleinsäuren vonE. coli 15 arg^– t ^– u ^– findet nicht statt, unabhängig, ob die Mikroorganismen in komplettem oder Basen-defizitärem Nährmedium wuchsen.     

Inhibition of mammalian acetylcholinesterase by phenylmethanesulfonyl fluoride

Resumen El fenilmentano sulfonil fluoro (FMSF) 4×10^–5 M inhibe a la acetilcolinesterasa (E. C. 3.1.1.7) de cerebro de rata en más de 50%, y 9×10^–4 M más de 90%. La constante de reacción inhibidor enzima es de 4.7×10² (1 mol^–1 min^–1). La colinesterasa (E. C. 3.1.1.8) de cerebro de rata es insensible a FMSF.

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Supported by NIMH Grant No. 1 RO3 MH 19125, by Comisión Nacional de Investigación Cientiffica Proyecto No. 80, and by Comisión de Investigación Cientiffica Universidad de Chile, Proyecto No. 95.     

Kälte als Auslöser einer Glykogen-Speicherung während der Oogenese vonMusca domestica

Summary InMusca domestica reared under standard conditions (21 °C), glycogen is stored in the oocyte towards the end of egg development. By 1–3 days exposure to lower temperatures (4 °C), a glycogen deposition can be released already in young follicles. This premature glycogen synthesis is not restricted to the ooplasm. Carbohydrates are also found in the nurse cells and the follicle epithelium. Similar results were formerly obtained by inhibition of oogenetic protein synthesis.

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Herrn Prof. Dr. Dr. h.c.Bernhard Rensch zum 70. Geburtstag gewidmet.     

Das Auftreten von Koproporphyrin in Kulturen vonPoteriochromonas stipitata nach Inkubation mit 3-Amino-l,2,4-triazol (Amitrol)

Summary In the presence of more than 2×10^–3 M amitrole, a red pigment was synthesized in the unicellular algaPoteriochromonas stipitata. By means of TLC it was confirmed that it consists mainly of coproporphyrine.     

Experimental data on the energetic flux during glycolytic oscillations in yeast extracts

Calorimetric experiments were performed on yeast extracts in which glycolytic oscillations were occurring. High metabolic fluxes coincided with low amplitudes and with high frequencies in a temperature range from 283 to 303 K, yielding an activation energy ofE _a=76.8 kJ mol^–1 and a mean Q₁₀ value of 2.5±0.4. The calorimetrically determined reaction enthalpy _fH^0, of the glycolytic catabolism of glucose revealed two distinct groups of extract preparations, with no intermediate values. The values were –107.5±28.7 kJ mol^–1 and –30.8±5.7 kJmol^–1, respectively, while –100.0 kJ mol^–1 was predicted from theoretical calculations. Kreuzberg and Betz⁶ predicted rate limiting effects of GAPDH in oscillating extracts. However, when possible effects of GAPDH on frequency, number of oscillations or total heat production were examined, no influence of increasing or reducing the initial GAPDH concentration could be found. The results are discussed with reference to existing models of glycolytic oscillations.     

Influence of atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) on auxin metabolism of plants

Zusammenfassung Die Enzymaktivität der IES-peroxidase in Hafer-Koleoptilen wurde durch Atrazin in Konzentrationen von 10^–10–10^–21 M gehemmt, im Konzentrationsbereich von 10^–6–10^–8 M gesteigert. Atrazin förderte ferner das Wachstum von Sojabohnen-Kallusgewebe in Gegenwart von 5 mg/l Kinetin und 10^–10 bis 10^–18 M Atrazin im Nähragar. Diese Einwirkung von Atrazin auf den Wuchsstoffmetabolismus der Pflanzen gibt erste Anhaltspunkte, die zahlreich beobachteten Förderungen bzw. Hemmungen des Pflanzenwachstums unter dem Einfluss von Atrazin zu erklären. Die Resultate bilden weiterhin eine neue Grundlage für eine mögliche Interpretation des «Proteineffekts» der Triazine.     

Bicarbonate and chloride transport across rat ileal basolateral membrane

The mechanisms of HCO ₃ ^– and Cl^– transport across basolateral membranes from rat ileum were investigated in isolated vesicles by means of uptake experiments. Neither Cl^–/HCO ₃ ^– exchanger nor Na⁺–(HCO ₃ ^– )_n cotransport seem to be present in ileal basolateral membranes. Moreover Cl^– uptake is unaffected bycis Na⁺ and/or K⁺ gradients, indicating the absence of Na⁺–Cl^–, K⁺–Cl^– and Na⁺–K⁺–2Cl^– symport activity. An electrically conductive pathway seems to be responsible for both HCO ₃ ^– and Cl^– fluxes. Evidence is also given for the presence of a Na⁺/H⁺ exchanger at the basolateral pole of ileal enterocytes.     

Naringenin inhibition on expiants in vitro ofCichorium intybus (Chicory)

Riassunto La naringenina alla concentrazione di 10^–4 M inibisce in modo totale l'emissione di gemme in radici diCichorium intybus in vitro senza tuttavia bloccare completamente la callogenesi. A concentrazioni scalari minori (10^–5, 10^–6, 10^–7 M) questa sostanza causa una inibizione solo nella fase iniziale dell'esperienza.