Ion-solvent interaction: Viscosity,apparent molar volume and conductivity of univalent electrolytes in dioxanewater mixtures at different temperatures

Summary The viscosity, apparent molar volume and conductivity of NaCl, KCl, NaBr, KBr, NaNO₃ and KNO₃ solutions at mass fraction of dioxane (10, 20 and 30%)-water mixtures at 30–45°C±0.01°C have been measured. The ions appear to interact appreciably, and the ion-solvent interaction is of the order NO₃ ^–>Br^–>Cl^–.     

Studies on hydrogen,halides and thiocyanate ions in dioxane-water mixtures at various temperatures

Summary The free enrgies of transfer (G _t ⁰ ) of H⁺, Cl^–, Br^–, I^– and SCN^– ions from water to 10, 20, 30 and 40% dioxanewater mixtures have been studied from potentiometric measurements. For anions the G _t ⁰ values are in the order Cl^–>Br^–>SCN^–>I^–.     

Dissociation-constants of metal-ion-complexes with alkaline phosphatase from pig kidney

Summary Using metal-ion buffers it was possible to remove Zn²⁺, Mg²⁺ and Mn²⁺ ions of pig kidney alkaline phosphatase reversibly. The dissociation constants obtained are K_EMg:4·10^–7 M, K_EMn:4·10^–8 M and K_EZn:8·10^–13 M (22°C, pH:9.6, :0.07).Acknowledgement: The authors thank Dr.H. U. Wolf for helpful suggestions and valuable discussion and MissH. Köth for technical assistance.     

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.     

The number of neurons,glial and perineurium cells in an insect ganglion

Zusammenfassung Im zweiten Abdominalganglion der Indischen Stabheuschrecke (Carausius morosus Br.) wurden 600 ± 50 Neurone, 1000 ± 100 Gliazellen und 500 ± 30 Perineuriumzellen, zusammen etwa 2100 Zellen gezählt. Die Volumina des Ganglions, des Neuropilems und des Zellcortex betrugen etwa: 140 · 10^–4 mm³, 75 · 10^–4 mm³ und 65 · 10^–4 mm³.     

Negative adsorption of anions by suspensions of bentonites

Résumé Nous avons étudié l'adsorption négative des anions I*O ₃ ^– et Cr*O ₄ ^–– à différents bentonites en fonction d'électrolytes additionnés. Pour les électrolytes NaCl et Na₂SO₄ les résultats sont en bon accord avec ceux deSchofield etMattson; nous avons étudié aussi l'effet de l'addition de solutions de CaCl₂; celles-ci produisent le même effet à des dilutions 20 fois plus grandes que les solutions de NaCl. Comme ceci ne peut pas être expliqué sur la base de la théorie deDebye-Hückel, nous avons appliqué la théorie exacte de la couche double; le facteur 20 mentionné plus haut mène à une valeur de=–75 mV. En introduisant cette valeur de, une représentation graphiques–1/c pour les résultats des expériences au Na-bentonite + solutions de NaCl, donne une surface spécifique de 1110 m²/g.     

RNA polymerisation capacity and permeability to ribonucleoside triphosphates of nuclei from livers of wholebody X-irradiated rats

Summary For 4–18 h following whole-body X-irradiation of rats, liver nuclei showed a progressive increase in the permeability to ribonucleoside triphosphates (as assessed in vitro using tritiated uridine triphosphate (UTP)) and in the capacity to polymerise RNA in vitro (Mg⁺⁺-containing and Mn⁺⁺/(NH₄)₂SO₄-containing assay systems).     

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.     

The effect of ammonium ion upon ribonucleic acid polymerase and guanidine triphosphatase activity in isolated bovine endometrial nuclei

Zusammenfassung Die Wirkung von 0,3M (NH₄)₂SO₄ auf die RNS Polymerasen und GTPasen Aktivität wurde in einem System isolierter endometrialer Zellkerne bovinen Ursprungs untersucht. Bei Zugabe von NH ₄ ⁺ verlief die RNS-Polymerasen Reaktion für 2 h linear, anstatt nach 20–30 min in ein Plateau einzumünden. Dies beruht nicht auf einer zweiten RNS-Polymerase, sondern auf der Hemmung der GTPase, welche das Substrat mit wesentlich höherer Reaktionsgeschwindigkeit umsetzt.     

Aufhebung der Thermothyrin-A-Sekretion der Schilddrüse durch Fütterung mit Methylthiouracil

Summary G. Mansfeld demonstrated that in the serum of overheated animals a substance (thermothyrine A) is present which, injected into normal animals, decreases O₂-consumption. Serum of thyroidectomized animals has no effect.Dogs and rabbits were treated daily with 0.10 g per kg methylthiouracil during 4 weeks, and were than subjected for 5 hours to a temperature of 34–35° C which raised their body temperature by 0.5–1.5° C. 2.5 cm³ of serum obtained at the end of the 5 hours period failed to reduce O₂-consumption of normal rats, while sera of untreated dogs and rabbits produced after similar exposure to high temperature a fall of O₂-consumption by 14–48%. It is therefore evident that methylthiouracil not only inhibits the formation of thyroxine but of thermothyrine A as well.The fact that thermothyrine A contains no iodine proves conclusively that the action of thiouracil compounds cannot be exclusively an inhibition of iodinization.     

Pendulin,a new biscoclaurine alkaloid fromCocculus pendulus diels

Zusammenfassung Ein Biscoclaurin Alkaloid, Pendulin (C₃₇H₄₀N₂O₆), mp 192–194°, []_D + 265°, wurde aus Blättern und Stamm vonCocculus pendulus Diels isoliert und seine Struktur (I) inklusive der sterischen Anordnung an beiden Asymetriezentren aufgeklärt.

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Communication No. 1414 from the Central Drug Research Institute.     

A pyruvate kinase variant in different mouse transplanted tumors

Summary Mouse transplanted tumors, in contrast to normal tissues, contain a pyruvate kinase (PK) variant sensitive to the inhibitory action of L-cysteine and less sensitive to saturated fatty acids than the normal enzyme. In selected normal and tumor materials two fractions of PK were separated. Fraction A (20–30% (NH₄)₂SO₄ saturation) dominated in normal liver, and fraction B (50–60% (NH₄)₂SO₄ saturation) in skeletal muscles and Ehrlich ascites tumor. Only this fraction B from tumor material was sensitive to L-cysteine, and seems to contain a tumor-specific PK variant which might be considered as a marker of neoplastic transformation in a broad spectrum of mouse experimental tumors.     

Influence of environmental conditions on the amount of N2O released from activated sludge in a domestic waste water treatment plant

Waste water purification is characterized by intensive mineralization and nitrification processes. Because of the high O₂ demand, temporarily anaerobic conditions may be produced, and denitrification by nitrifying organisms as well as heterotropic denitrification may contribute to N₂O release. In situ measurements (1993–1994) suggest that N₂O is released from activated sludge in a domestic waste water treatment plant at an average rate of 1040 g m^–2h^–1 with a range between zero and 6198 g m^–2h^–1. The production of N₂O seems to be related to the concentration of NO ₂ ^– and NO ₃ ^– as well as to the pH. In the waste water about 75–200 g N₂O l^–1 is dissolved. This N₂O is released after discharge into the receiving waters. The N₂O is produced essentially by nitrification rather than by heterotropic denitrification. On a long-term scale the increasing use of mechanical-biological waste water purification plants world-wide may add increasingly to the anthropogenic production of N₂O, although the present amount of N₂O produced is negligible compared to its global terrestrial production.     

Endogenous gibberellins and amylase activity in tall and dwarf strains of rice (Oryza sativa)

Summary 2 tall and 7 dwarf strains of rice were sprayed with 0 or 40 g ml^–1 GA₃, 4 dwarf strains responded to exogenous GA₃, and showed a markedly lower endogenous gibberellin content than the tall strains, while 2 dwarf strains did not respond to GA₃ application and had considerably higher endogenous gibberellin levels than the tall ones. Amylase activity in germinating seeds showed a significant negative correlation with the endogenous gibberellin content.     

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.     

Respiratory burst in peritoneal exudate cells in response to a modified tuftsin

Intraperitoneal administration of tuftsin-M [Thr–Lys–Pro–Arg–NH–(CH₂)₂–NH–CO–C₁₅H₃₁] to Balb/C mice has been shown to induce a respiratory burst in the peritoneal exudate cells. The macrophages exhibited enhanced levels of O₂ ^–, H₂O₂, NADPH oxidase and myeloperoxidase, but the activities of superoxide dismutase, catalase and glutathione peroxidase remained virtually unchanged. The magnitude of the oxidative burst depended directly on the dose of tuftsin-M; higher activity was observed at higher doses of the peptide. Tuftsin-M enhanced the generation of both O ₂ ^– and H₂O₂ under in vitro conditions, as did phorbol myristate acetate. These results suggest that tuftsin-M could enhance non-specific defence against infections by activating the macrophages.     

Soybean photosynthesis: simultaneous14CO2 and O2 estimates

Summary A method of estimating the photosynthetic rate of soybean leaves using an oxygen electrode is presented. The procedure is rapid, requires small samples and compares favourably with estimates by other techniques. Light saturation occurs at 1200 E·m^–2·sec^–1. The apparent K_m for HCO ₃ ^– is 3.2 mM at pH 7.6.     

Limited proteolysis of lactate dehydrogenase from procine heart with trypsin: Characterization and reactivation of the fragments

Summary The ternary complex formed by native lactate dehydrogenase (LDH) from porcine heart, NAD⁺ and sulfite, was digested with trypsin over a period of 12–16 h³. After removal of the ligands and residual native lactate dehydrogenase by ion exchange chromatography dimers were obtained which were almost inactive. The dimers were lacking a hexapeptide at the N-terminus; however, the secondary structure was the same as that of native lactate dehydrogenase. The circular dichroism spectra showed a dependence on temperature which suggested an equilibrium of two different structural states.The reaction of antibodies against native porcine heart LDH with the dimers restored the catalytic activity, and subsequently the dimers behaved similarly to the native enzyme. Addition of 1 M phosphate or NAD-sulfite to the dimers restored 80–90% of the catalytic activity. It could be demonstrated that the behaviour of the reactivated dimers, in contrast to that of the inactive dimers, was similar to the behaviour of native lactate dehydrogenase. For instance, ultracentrifugal analysis showed that dimers reactivated with NAD–SO₃ ^– were associated to give tetramers.The reaction of antibodies against native LDH with the dimers reactivated with NAD–SO ₃ ^– demonstrated that the native LDH and the dimers have the same surface determinants.     

Die katalytische Mutation der Ionen Al3+ und MoO

Summary The catalytic mutation of the ions Al³⁺ and MoO ₄ ^2– on the mixed carrier Cd(OH)₂/Co(OH)₂(Tr) is recognizable by the fact that the combination Tr+Al³⁺+MoO ₄ ^2– is more active in the decomposition of H₂O₂ than the combination Tr+MoO ₄ ^2– +Al³⁺.     

Thermodynamics of bromate and iodate of potassium in dioxane-water mixtures from conductance measurements

Summary The free energy of transfer ( G _t ⁰ ) of KBrO₃ and KIO₃ from water to 10, 20 and 30% dioxane-water mixtures have been studied from conductometric measurements. The G _t ⁰ values are in the order of BrO ₃ ^– >IO ₃ ^– .