Lichtinitiierte polymer- und polymerisationsreaktionen, 26. Elektrophile ringöffnungsreaktionen zwischen glycidylethern und ketonen oder aldehyden initiiert durch photoinitiatorsysteme

By the irradiation of benzoin derivatives in the presence of arene diazonium salts or aryl iodonium salts cationic species are formed, which initiate ring-opening reactions of 2,3-epoxy-propyl (glycidyl) ethers in the presence of ketones or aldehydes. 1,3-Dioxolane formation dominates over homopolyaddition reactions of glycidyl ethers. This method forms dioxolane in satisfactory preparative yields. The quantum yields of disappearance of phenyl glycidyl ether in acetone (Φ_PGE) were measured in dependence of some system parameters. By the photolysis of benzil dimethyl ketal more catalytic species are produced as in the case of benzoin isopropyl ether or α-phenylbenzoin. The Φ_PGE values for diazonium salts are higher than for iodonium salts, with triphenylsulfonium salts the reaction failed. With the anions of iodonium salts the following sequence for Φ_PGE is observed: SbF₆^? > PF₆^? ? SbCl₆^? = BF₄^? = 0. Because the key step of the catalyst formation is an electron transfer reaction between radicals produced by the photolysis and the onium ions, the concentration of the salts influences Φ_PGE. Phenyl glycidyl ether reacts more rapidly than 2,2-bis(4-hydroxyphenyl)trimethylene diglycidyl ether and isobutyl glycidyl ether.     

Lichtinduzierte polymer- und polymerisationsreaktionen, 44. Zur kinetik der radikalischen photopolymerisation mehrfunktioneller acrylate in polymeren bindemitteln

With calorimetric measurements the kinetics of the free-radical polymerization of various diacrylates in several polymeric binders have been investigated. The reaction was initiated by radicals formed through photolysis of α-isopropoxydeoxybenzoin. In each case, the polymerization rate depends on the conversion degree. Mainly, this fact results from changes in the termination mechanism of the polymerization chain reaction. By means of the light intensity exponent such mechanistical changes can be quantitatively followed. Both, the results obtained by stationary and non-stationary irradiation experiments lead to the same conclusions. The properties of the polymeric binders possess a stronger influence on the kinetics compared with the structural changes of the diacrylates used.     

Radikalische abbruchsprozesse III. Die Wahrscheinlichkeit der Reaktion zwischen polymer- und primärradikalen und ihre beeinflussung durch die kettenendverteilung im knäuel und durch die Lebensdauer der Reaktanten

The procedure based on the solution of the equation of threedimensional diffusion, which has been used to calculate the probability of the reaction between free radical chain ends of two coiled polymer radicals after the first contact between the coils has been formed, has been modified for the reaction between a coiled macroradical and a (dimensionless) primary (micro)radical (primary radical termination). The reaction probability is independent from the distribution of the radical chain end in the macroradical. If there is infinite time for the reaction between the two reactants (if the life-time of the two specific reactants considered is not limited by reaction with other species) the microscopic and the macroscopic rate constants of primary radical termination are identical. In case of finite life-times the effects on reaction probability and on the frequency of forming the first contacts cancel as a first approximation so that the equivalence between microscopic and macroscopic rate constant is mainly retained.     

Verwertung von L-Aspartat,L-Malat und Fumarat durch Pasteurella multocida

Strains of Pasteurella multocida use L-aspartate, L-malate and furmarate, respectively, as substrates for production of succinic acid which accumulates in the medium. As was established by studies with ¹⁴C and ³H labelled substrates, the degradation of these substances proceeds analogous via the citric acid cycle.     

Transport von K,Cl und Wasser durch die Muskelfasermembran

Zusammenfassung Es werden Froschmuskeln mit Ringer-Lösungen variierter K- und Na-Konzentrationen unter Konstanthaltung des osmotischen Drucks durchströmt. K wird proportional dem K-Angebot vom Muskel aufgenommen, die Na-Konzentration der Außenlösung nimmt zu. Die Konzentrierung des Na ist durch Wasseraufnahme des Muskels bedingt, da K als isotonische KCl-Lösung aufgenommen wird. Diese Ergebnisse entsprechen quantitativ der Conwayschen Theorie, wonach bei Erhaltung des osmotischen Gleichgewichts die Verteilung von K und Cl zwischen Muskelfaser und extracellulärem Raum durch das Donnan-Gleichgewicht bestimmt wird.Mit 1 Textabbildung.     

Reduktion von Nitrat und Nitrit durch Neisseria

Zusammenfassung 52 Stämme aller bekannten Arten vonNeisseria wurden auf ihre Fähigkeit zur Nitrat- und Nitritreduktion sowie zur Ammoniakbildung untersucht.Es ergab sich, daß — mit Ausnahme der mikroaerophilenN. gonorrhoeae — alle zuckerverwertenden Arten Nitrit denitrifizieren, ohne Nitrat in nennenswertem Maße anzugreifen. Ebenso verhalten sich die meisten Stämme vonN. catarrhalis. N. caviae reduziert Nitrit ohne Gasbildung. Die kräftig nitratreduzierendeN. ovis ist dagegen indifferent gegen Nitrit. N. gonorrhoeae reduziert weder Nitrat noch Nitrit.Ammoniak wird von allen Stämmen in Spuren gebildet, von den menschenpathogenen Arten am wenigsten, vonN. ovis relativ am stärksten.Herrn Prof. Dr. Dr. K.Schuchardt zum 60. Geburtstag gewidmet.Die vorliegenden Untersuchungen wurden mit Unterstützung der Deutschen Forschungsgemeinschaft durchgeführt.     

Beeinflussung von Druck und Stromvolumen in der Pfortader durch die Atmung und durch experimentelle Eingriffe

Ohne Zusammenfassung     

Induktion von Fieber und Fiebertoleranz durch inkomplette Influenzaviren

Zusammenfassung In den vorliegenden Kaninchen-Pyrogenversuchen wurde die fieberauslösende und toleranzinduzierende Aktivität von kompletten und inkompletten Influenzaviruspartikeln vergleichend untersucht. Die Präparationen mit den vorwiegend inkompletten Viruspartikeln waren hinsichtlich dieser Eigenschaften den Ansätzen mit vorwiegend kompletten Viruspartikeln gleichwertig.Auf die Natur des exogenen Viruspyrogens und auf einen möglichen Mechanismus der Fiebertoleranz wird kurz eingegangen.

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Summary In rabbit pyrogen tests the pyrogenic activity and tolerance inducing property of both, complete and von Magnus incomplete influenza viruses are compared.The induction of fever and of homologous tolerance by incomplete viruses were equally to those by complete forms. The chemical structure of the exogenous virus pyrogen and a possible tolerance mechanism were discussed.

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Diese Untersuchungen wurden mit finanzieller Hilfe der Deutschen Forschungsgemeinschaft durchgeführt.     

Physiologie und Biochemie der Streptomyceten IX. Hydrolyse von Cyclohexyl-, Kohlenhydrat- und Arylester durch eine Carboxylesterase aus Kulturen von Streptomyces hygroscopicus JA 6599

Carboxylesterase in cell-free extracts of Streptomyces hygroscopicus was characterized with cyclohexylacetate and β-penta-acetyl-D-glucose as substrates. After concentrating the enzyme, activity with α/β-methyl-4-O-propionyl-L-mycarosid as substrate was also observed. The influence of enzyme effectors was studied. Esterase activity was also found in the culture filtrate of. S. hygroscopicus.     

Aufnahme von Cobalt,Blei und Cadmium durch Bäckerhefe

The toxicity for and the uptake by Saccharomyces cerevisiae of the essential trace element Co²⁺ and the non essential elements Cd²⁺ and Pb²⁺ were compared. Inhibition of yeast growth is observed 4 hrs after addition of Co at concentrations higher than 10^?4 M. Cd is about 100 times more toxic than Co and inhibits growth immediately after addition. No toxicity of Pb is observed with concentrations up to 5 · 10^?4 M. For uptake experiments the radioactive isotopes ⁶⁰Co, ^115mCd and ²¹⁰Pb were used. The yeast samples were washed with carrier solution in order to remove the isotopes adsorbed only by the cell wall and measured by γ-scintillation counting. Co uptake by yeast is strongly dependent on glucose both under aerobic and anaerobic conditions. There is no efflux of Co once taken up. Dead yeast does not accumulate Co at all. Co already taken up is released from cells when killed, indicating that no irreversible binding in the cell interior takes place. Co transport follows biphasic saturation kinetics with the MICHAELIS constants K₁ = 10^?4 and K₂ = 8 · 10^?4 M and the maximal velocities ν¹ = 9.5 and ν₂ = 63 μ moles/g dry weight · hr. The Q₁₀ for Co uptake from 10^?4 M solution is 2.3. Uptake of Cd resembles that of Co. The absorption of Cd is also glucose-dependent, but independent of the presence of air, no Cd is taken up by dead cells, and Cd previously taken up is released during killing the cells. There is a considerable Pb uptake irrespective of the presence of glucose, and even by dead yeast. Killing of the yeast during uptake does not lead to loss of Pb. It is concluded that the essential trace element Co is accumulated by an energy-dependent, probably active, transport system in the membrane. Cd is similarly transported, probably because of its chemical similarity to Zn. In contrast, Pb appears to be taken up only by diffusion, but subsequently to be trapped by binding in the cell interior. In this way, the accumulation of Pb is similar in amount to those of Co or Cd although the mechanisms differ widely.     

Modifizierung von homo- und copolymeren des epichlorhydrins durch polymeranaloge umsetzungen

Poly(epichlorohydrin) and poly(epichlorohydrin-co-ethylene oxide) were modified by reaction with potassium thiocyanate (KSCN), tetrabutylammonium p-toluenesulfinate (NBu₄SO₂C₇H₇) and tetrabutylammonium benzenesulfinate (NBu₄SO₂C₆H₅). Though the substitution of chlorine in the polymers with these nucleophilic reagents in most cases is accompanied by side reactions, appropriate reaction conditions allow degrees of substitution higher than 90% to be obtained. The glass transition temperature (T_g) of the thiocyanate-modified homo- and copolymer exhibits only a small increase with increasing degree of substitution. While the T_g of the original homo- and copolymer is observed at ?20°C and ?38°C, respectively, the glass transition of the highly substituted homopolymer occurs at ?12°C and for the copolymer at ?31°C. On the other hand, the thiocyanate-modified polymers show a remarkably higher decomposition temperature of about 250°C as compared with that of the unmodified polymers (160–180°C). In addition, the solubility is markedly influenced by the substitution. While the original homo- and copolymers are soluble in, e.g., benzene and toluene, the highly modified products are only soluble in polar solvents such as THF, acetone, DMSO and diglyme. Introducing sulfonyl groups, the resulting polymers exhibit a glass transition temperature increased to a greater extent. For the homopolymer with the highest degree of substitution (98,3%), a T_g of 73°C is observed. Concerning the decomposition temperature, a drastical increase up to 370°C occurs. Finally the influence of phase transfer catalysts on the described reactions was investigated.     

Die Beeinflussung von Enzymen in Uterus und Placenta durch Oestrogene

Ohne ZusammenfassungDie experimentellen Arbeiten des Autors wurden unterstützt durch Stipendien des Charles and Marjorie King Fund, von der Association for the Aid of Crippled Children, und von den National Institutes of Health, Bethesda, Md. (Kontrakt Nr. C-2400). — Deutsche Übersetzung:H. Jahrmärker, München.     

Bildung von Phaseolotoxin und Phosphosulfamylornithin durch Pseudomonas syringae pv. phaseolicola in Submerskultur

Phaseolotoxin (N^δ-phosphosulfamyl-ornithyl-alanyl-homoarginine) from culture-supernatants of Pseudomonas syringae pv. phaseolicola and N^δ-phosphosulfamylornithine (PSOrn) obtained from phaseolotoxin by treatment with leucine aminopeptidase were compared in regard to their inhibition effects by means of the enzymatic toxin test as well as by bioassay. In the enzymatic toxin test PSOrn exhibits an inhibiting effect five times stronger than that of phaseolotoxin. The maximal inhibition due to PSOrn is also higher. On the other hand, only phaseolotoxin caused growth inhibition in the bioassays used (indicator organisms: Escherichia coli, Euglena gracilis). Tests are presented which allow to detect these compound selectively. Their application showed that the strain studied produced phaseolotoxin as well as PSOrn in submerged cultures.     

Bestimmung der Copolymerisationsparameter und Depolymerisationskonstanten von Methylmethacrylat-Acrylnitril-Copolymeren durch Protonenspinresonanz

It is shown how copolymerization parameters and constants of depolymerization can be obtained from NMR- or IR-spectra of copolymers if depolymerization reactions occur during the copolymerization. Relations are derived between these quantities and the concentrations of diads or longer sequences in the molecular chains which can be determined by spectroscopical measurements. The equations are valid for the general case that all growthreactions are reversible during the copolymerization. The applicability of the method was tested by NMR-measurements of methylmethacrylate-acrylonitrile-copolymers which were obtained via radical polymerization at temperatures between 50 and 180°C.     

Physiologie und Biochemie der Streptomyceten XIII. Biosynthese von Paromomycin unter Einsatz von 14C-Glucose, -Glucosamin, -2-Desoxystreptamin und -Ribose durch Streptomyces albus var. metamycinus nov. var.

Distribution of radioactivity in paromomycin ascertained after application of ¹⁴C-D-glucose, ¹⁴C-D-glucosamine, ¹⁴C-2-deoxystreptamine, respectively, ¹⁴C-D-ribose is taken as basis for a biosynthesis scheme: While ribose bound in the antibiotic originates from glucose by oxidation and following decarboxylation, glucosamine is formed via fructose-6-phosphate. Paromose I arises from glucosamine, but not the cyclohexan derivative 2-deoxystreptamine, whose biosynthesis pathway is directly branching off glucose.