bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal structure and thermal decomposition of the Silanimine tBu2Si=N-SitBu3·thf
Authors: Schödel Frauke , Bolte Michael , Lerner Hans-Wolfram 
Published: August 2018

Abstract
The thf-complexed silanimine tBu2Si=N–Sit- Bu3·thf (1(thf); monoclinic, space group C2/c) was prepared by the reaction of 1 equivalent of tBu2SiClN3 with 1 equivalent of Na[SitBu3] in Bu2O and subsequent addition of thf. By heating a benzene solution over a period of 11 d –140 °C, 1(thf) slowly released the thf donor to form the uncomplexed silanimine 1. However, under these conditions the silanimine 1 is unstable and is thermolized to give the ene reaction product of 1 with isobutene, H2C=C(CH2SitBu2–NH–SitBu3)2. By contrast, the thermolysis reaction of Me2Si=N–SitBu3·thf yielded the silanimine dimer (Me2SiNSitBu3)2 in 51 % and the vinyl ether Me2Si(OCH=CH2)NHSitBu3 in 49 % yield.
ᴅ-Aspartyl-ʟ-alanin als Interpeptidbrücke im Murein von Bacillus pasteurii Migula / ᴅ-Aspartyl-ʟ-alanine an Interpeptide Bridge of the Murein of Bacillus pasteurii Migula
Authors: Ranftl H. , Kandler O. 
Published: August 2018

Abstract
-A spartyl-L -alanine an In te rp e p tid e Bridge of the M urein of Bacillus pasteurii M igula H . R a n f t l u n d O . K a n d l e r Murein structure, Bacillus pasteurii The murein (peptidoglycan) of the cell walls of 4 strains of B. pasteurii was analysed. In vegetative cells the peptide subunits consist of L-Ala-N^-D-Glu-L-Lys-D-Ala while the in te r­ peptide bridge bond to the e-am inogroup of L-Lys consists of N-/ff-D-Asp-L-Ala. The spores contain a m urein of the meso-DAP-type. In the strain ATCC 6453 about 30 °/o of L-Ala of the interpeptide bridge is replaced by L-Ser.
Membrane and Vesicle Formation from Fragments and Proteins of Thylakoids
Authors: Menke Wilhelm , Radunz Alfons , Koenig Friederike 
Published: August 2018

Fragments of the thylakoid membrane, obtained by ultrasonication of stroma-freed chloroplasts and subsequent fractioning centrifugation, aggregate in buffer solutions of suitable ionic strength in the pH-range of 6.0-8.5. This aggregation leads to the formation of vesicles and membranes, which may reach a size of up to 0.5 mm. A suspension of the fragments, having an average diameter of 100 Å, is stable in water.
A protein preparation, obtained by treatment of stroma-freed diloroplasts with sodium deoxycholate and subsequent gel filtration, contains 4 % chlorophyll but no detectable amounts of colourless chloroplast lipids, nor deoxycholate. This preparation aggregates in the pH-range of 6.0-7.0 equally to membranes and vesicle-like structures. The solution of this protein, exhibiting a molecular weight of 600 000, is stable in water.
The proteins of both preparations are not denatured and both preparations exhibit photochemical reactions.
Bacteriophage Conjugates: The Effect of Coupling Reaction and Specific Antibodies on the Kinetics of Inactivation and Reactivation
Authors: Mossmann Horst , Hammer Dietrich K. 
Published: August 2018

The reaction of bacteriophage T4 with 1-fluoro-2,4-dinitrobenzene resulted in a covalent binding of 2,4-dinitrophenyl (DNP) determinants to the phage. From the kinetics of inactivation reflecting the coupling process it is concluded that attachment of more than one DNP group to the critical site(s) of the phage is required for inactivation (multi-hit reaction). Contrary to this the neutralization of DNP-T4 by anti-DNP antibody turned out to be a first order reaction, until 80 %> neutralization fitting one-hit kinetics.
If compared with native T4, the susceptibility of DNP-T4 to neutralization by anti-T4 antibody is considerably higher, indicating that attachment of DNP groups to T4 amplifies the sensitivity to neutralization by anti-T4. Comparing neutralization kinetics of DNP-T4 and native T4 by anti-DNP-T4 antibody it is suggested that native determinants and DNP groups, as well as determinants resulting from alteration due to the coupling process, all together may contribute as targets for neutralization. Three characteristics strengthen the view that the velocity of T4 conjugates in infecting the host strain is markedly decreased if compared with that of native T4: (a) considerable discrepancy between direct plating and decision technique (b) increasing variety of plaque size and (c) decreased velocity of the first step of reproduction. The kinetics of neutralization observed can be reconciled with a model proposed by Krummel and Uhr. The kinetics of reactivation of neutralized DNP-T4 by the presence cf DNP-BSA has been investigated and the problems involved in the reaction are discussed.
Zur Deutung der Karzinogenität aus dem UV-Spektrum von 3.4 - Benzpyren und 1.2-Benzpyren / Interpretation of Carcinogenesis from UV-Spectra of 3,4 - Benzpyrene and 1,2-Benzpyrene
Authors: Popp Fritz A. 
Published: August 2018

The comparsion of the experimental UV-spectra of 3,4-BP and 1,2-BP requires a possible coupling of pure a~ and p-states for 3,4-BP through an asymmetric potential in the order of thermal energy.
The former postulated resonance hypothesis of carcinogenesis is supported with the obvious assumption that the energy change of a- and of the carcinogen with the bioreceptor.
Influence of Environment on the Photooxidation of Tryptophan with the Carcinogenic Hydrocarbon 3,4-Benzopyrene in Aqueous Solutions of Soap, Caffeine, and Urea
Authors: Reske Günter , Bauer Horst 
Published: August 2018

Abstract
The solvent dependence of the photooxidation of tryptophan and 3,4-benzopyrene in aqueous solutions was studied by quantum yield measurements. When the hydrocarbon is dissolved in aqueous solution of caffeine, the quantum yields indicate a 3,4-benzopyrene photosensitized trypto­ phan oxidation instead of a photocooxidation, which is indicated in aqueous solution of sodium dodecylsulfate. The same photosensitized oxidation as in caffeine solution is observed, when urea (6 ᴍ) is added to the soap solution, while the fluorescence and absorption spectra indicate no change in the solvation state of the hydrocarbon, comparable to the change from hydrophobic solubilization by the detergent to dipole - induced dipole complex solubilization by caffeine. It is concluded that the difference in the reaction pathways is caused by different solvation states of the excited or reacting oxygen. In the discussion of the results it is referred to reactions of inhibitors.
Hydrogen Bonds between Sexual Hormones and Nucleobases: NMR Investigations *§
Authors: Schimmack Wolfgang , Lohmann Wolfgang 
Published: August 2018

Abstract
The hydrogen-bonded complexes of 17 α-ethinyl-estradiol, progesterone, and testosterone with adenine- and uracil-derivatives have been investigated by means of nuclear magnetic resonance (NMR) spectroscopy using deutero-chloroform as a solvent. The thermodynamic and NMR-parameters (equilibrium constant K, enthalpy ΔH, entropy ΔS, and relative chemical shift of the complexes ΔδC) for selfassociation and mixed association have been determined. The strongest complex was formed by the phenolic hydroxyl group of estradiol with dimethyl-adenine (K = 14 mole- 1 , - ΔH = i kcal/mole, - ΔS = 8 cal/m ole-grad). The values were considerably less for the OH-17 group of estradiol and testosterone. The interaction of the keto groups of progesterone and testo sterone with nucleobases was very weak: K < 1 .0 mole- 1 . The biological importance of these results is discussed.
Electron Spin Resonance of Free Radicals and Radical Pairs in Irradiated Single Crystal of 1-Methyluracil
Authors: Flossmann Wolfgang , Hüttermann Jürgen , Müller Adolf , Westhof Eric 
Published: August 2018

Abstract
Radical formation by irradiation with X-rays in single crystals of 1-methyluracil has been measured using ESR-spectroscopy at 9.5 GHz and 35 GHz. When irradiating and measuring at 77 °K radicals characterized by hydrogen abstraction from the methyl group were found to be predominating. For the hyperfine splittings principal values of 8.5 G, 18.2 G, 30.5 G were found for both α-protons and 3.3 G, 2.4 G, 1.7 G for the N (1)-splitting. Pairs of abstraction radicals were also found under these conditions showing quintet splittings of about 10 G and anisotropic dipolar coupling. Average distances parallel to c of 6.3 Å and 6.5 Å were found for two types of pairs while those perpendicular to c were not analyzed in detail. Irradiating and measuring at room temperature an additional sextet pattern was found in the spectrum and attributed to a radical formed by addition of hydrogen at C (5). For the hyperfine splittings principal values of 8.1 G, 17.5 G, 30.0 G were found for the α-proton and 31.2 G, 34.4 G, 34.1 G for the two equivalent β-protons. Radical concentrations were determined at 77 °K yielding about 90% abstraction radical, 15% of these in pairs and 10% of addition radical. About half of the abstraction radicals are converted to addition radicals between 200 °K and 280 °K. The latter disappear at about 460 °K leaving a fraction of abstraction radicals which is annealed at even higher temperatures.
Control by Phytochrome of Glutathione Reductase Levels in the Mustard Seedling
Authors: Drum H. , Mohr H. 
Published: August 2018

Abstract
The time-courses of the level of glutathione reductase (GR; EC 1.6.4.2) were followed in cotyledons and hypocotyl of the developing mustard seedling in the dark and under the influence of light (phytochrome). Localization of GR on polyacrylamide disc electrophoresis columns indicate that 2 isoenzym es of GR are present in both organs under all experimental conditions. GR can be induced by light (phytochrome) in the cotyledons; however, there is no influence of light (phytochrome) on the time-course of the level of GR in the hypocotyl. While the actual lag-phase of the response in the cotyledons is less than 6 hours (onset of light at 48 hours) there is no detectable effect of light on apparent GR synthesis before approx. 42 hours after sowing. Irrespective of the onset of light (at 24 or 36 hours after sowing) the time-course of the enzyme level remains precisely the same. A red pulse given at 24 hours after sowing leads to an increase of the enzyme level as determined 60 hours later. T he effect of the red pulse is fully reversed by a far-red light pulse given at 24 hours but not 12 hours later. Facts of this kind have led to the concept of a stable inter­ mediate in the chain of regulatory events between phytochrome (P fr) and GR increase. No in d i­ cations of a coordinated, simultaneous induction by phytochrom e of GR and ascorbate oxidase (AO) could be found. This result does not support the concept that a respiratory chain exists in which AO functions as a terminal oxidase.
Gap and Low-Resistance Junctions between Cells in Culture
Authors: Hülser Dieter F. , Demsey Anthony 
Published: August 2018

Abstract
Established lines of both fibroblastoid and epithelioid cells have been investigated by electro-physiological and freeze-fracture methods. Between the ionically coupled (by "low-resistance junctions") fibroblastoid cells numerous gap junctions were found. Between the non-coupled epithelioid cells gap junctions could not be detected.
A Simplified Procedure for Large Scale Preparation of Purified Animal DNA-Dependent RNA Polymerase
Authors: Schmincke C. D. , Hausen P. 
Published: August 2018

Abstract
A procedure is described for obtaining DNA-dependent RNA polymerase form B from calf thymus in high purity. The procedure includes homogenization in low salt, sedimentation of chromatin at 50 000 x g, adsorption to DEAE-cellulose in a batch procedure, DNA-agarose chromato­graphy, and chromatography on DEAE-Sephadex. Analyses of the preparation by band sedimentation and gel-electrophoresis indicate a high purity of the enzyme.
The Membrane ATPase of the (Mg, Ca)-ATPase-Mutant 12, strain AN 120
Authors: Günther Theodor , Mariß Gert 
Published: August 2018

Abstract
The activity of the membrane ATPase of the (Mg, C a)-ATPase-mutant E. coli K 12 strain AN 120 is reduced to about 5 - 50% of the wildtype ATPase. The reduction is greatest at pH 9.1 and a ratio of Mg, or Ca to ATP of 1 :5 , and smallest at pH 7.5 and 9.1 and a ratio of Mg or Ca to ATP of 1 or more.
Anreicherung der Leber-N-Acetyltransferase durch präparative Polyacrylamidgel-Elektrophorese und Bestimmung des Molekulargewichts /Purification of Human Liver Serotonin-/Isoniazid-N-Acetyltransferase by Preparative Polyacrylamidgel-Electrophoresis and Determination of Molecular Weight
Authors: Schulte Ernst , Schloot Werner , Goedde H. Werner 
Published: August 2018

Abstract
Human liver N-acetyltransferase was purified by means of column chromatography on Sephadex G-100 (18 fold; yield: 60-70%) and preparative disc electrophoresis (40 fold; yield: 95 - 100%). A separation of the hypothetical “serotonin-N-acetyltransferase” and “INH-N-acetyltransferase” on the basis of a possible difference of the charge of the proteins could not be achieved (disc electrophoresis). Thus the assumption is confirmed that INH and Serotonin are substrates of one enzyme.
The activity of N-acetyltransferase can be stabilized by adding thioglycolate, 2-mercaptoethanol, and cysteine. In some cases an activation of 100 to 200% could be observed.
A molecular weight of about 26 500 was determined by the method of column chromatography on Sephadex as well as by calculating the sedimentation coefficient.
Enzymes prepared by different procedures showed similar Kм-values.
De novo Synthesis of Glucose-6-Phosphate- (E.C. 1.1.1.49) and 6-Phosphogluconate Dehydrogenase (E.C. 1.1.1.44) in Plant Storage Tissue Slices
Authors: Kahl Günter 
Published: August 2018

Resting potato tuber tissue possesses only faint activity of the two dehydrogenases of the oxidative pentose phosphate cycle, glucose-6-phosphate- and 6-phosphogluconate dehydrogenase. Slicing of the tissue, however, greatly enhances the action of both enzymes. The slicing-induced increase in activity is a consequence of intensified action of at least 5 glucose-6-phosphate dehydrogenase isozymes and a more differentiated activation/inactivation of seven 6-phosphogluconate dehydrogenase isozymes.
Using density labelling and isopycnic equilibrium centrifugation it could be demonstrated, that the bulk of both enzymes appearing after slicing the tissue is the result of de novo synthesis rather than activation of pre-existing proenzymes.
Plasma Prostaglandins of the E and F Series in Rabbits during Fever Induced by Newcastle Disease Virus, E. coli-Endotoxin, or Endogenous Pyrogen
Authors: Philipp-Dormston W , Siegert R 
Published: August 2018

Abstract
Prostaglandins of the E and F series in rabbit plasma were estimated by radioimmunoassay after chromatographic separation during fever following the intravenous injection of Newcastle disease virus, E. coli-endotoxin, or endogenous pyrogen. Although concentrations of prostaglandins from both series are increased considerably by the three pyrogens, there seemed to be no correlation between prostaglandin concentrations in plasma and body temperature. These findings were supported by the fact, that after the injection of tritiated prostaglandin E1 into the carotid arteries of normal or feverish animals no radioactivity was detectable in cerebrospinal fluid. The enhanced prostaglandin concentrations in plasma night be responsible for various pathological effects observed during fever such as diarrhoea and abortion.
Iridoids and Ecdysones from Verbenaceae, V1
Authors: Rimpler Horst , Timm Helmut 
Published: August 2018

Abstract
Lamiid and three new iridoids have been isolated from Duranta repens. The new compounds - durantosid I (2), I I (3) and I I I (4) - are shown to be esters of lamiid with cinnamic acid, 4-methoxy-cinnamic acid and 3,4-dimethoxy-cinnamic acid respectively. The position of the cinnamoyl-groups has been determined by NMR-and mass spectrometry.
Molecular Complexes between Methoxyamphetamines and Riboflavin Derivatives
Authors: Sung Ming-ta , Parker John A. 
Published: August 2018

Abstract
Molecular complexes in the ratio 1:1 were formed in aqueous solution between various methoxysubstituted phenylisopropylamine (amphetamine) hydrochloride or oxalate salts and riboflavin deri­vatives (flavin mononucleotide and flavin adenine dinucleotide). The association constants for these complexes were determined by the fluorescence quenching method as well as by the absorption method. The nature of the complex formation may be due to charge-transfer, electron-transfer, electrostatic and hydrophobic forces. The steric effect also plays an important role in the complex formation. The absorption wavelength and association constant of the complexes are correlated with the published biological activities of the methoxyamphetamines.
Studies on the Chemical Modification of Trypsin
Authors: Ahmad S. I. 
Published: August 2018

Abstract
Dibenamine, Trypsin Dibenamine (N ,N-dibenzyl-β-chloroethylamine) a potent adrenergic blocking agent inhibits trypsin in an irreversible manner. Electrophoresis and peptide mapping (finger printing) have shown significant changes in the number of peptides and their mobility.
Eine Methode zur qualitativen und quantitativen Bestimmung von drei Juvenilhormonen von Insekten
Authors: Trautmann K. H. , Schuler A. , Suchý M. , Wipf H.-K. 
Published: August 2018

Abstract
A method is presented permitting the qualitative and quantitative determination of all three presently known hormones (JH1-3). The determination is based on the method of radioactive isotope dilution, whereby a very small known amount of tritium-labelled JH-1 is added to the ether extract of the particular species. The addition of radioactive JH-1 permits the isolation of all three hormones, because of their similar behaviour during the chosen work up.
The quantitative determination was carried out by gas chromatography and the identification was confirmed with the help of retention-times and GC-MS combination. The method was checked by using an extract of Hyalophora cecropia. For the first time methyl 10,11-epoxy-3,7,11-trimethyl-2-trans-6-trans-dodecadienoate (JH-3) could also be identified as the juvenile hormone of Melo­lontha melolontha. In Vanessa io larvae, Tenebrio molitor larvae and adults and in Musca domestica larvae none of the three known hormones could be detected.
The preparation of JH-1 labelled with tritium in the methyl group of the ester was accomplished with very high specific activity (4.34 Ci/mmol) of the tritiated acid with diazomethane.
Die biologische Bedeutung eines basischen Proteins (BBSP) aus dem Seminalplasma des Rindes / The Biological Significance of a Basic Protein (BBSP) from the Seminalplasma of the Bull
Authors: Gladigau V. , Ruhenstroth-Bauer G. 
Published: August 2018

1. The mean concentration of BBSP in the seminal bull plasma is 1.53 ± 0.30 mg/ml. This concentration decreases about 40% after 14 days storage at 4 °C.
2. There is only a small correlation between the concentration of BBSP in the seminalplasma and its fertilization capacity.
3. An artificial doubling of the normal BBSP concentration does not change the results of an artificial insemination.
4. The genital tract of bull has been investigated with immunofluorescent antibodies on the presence of BBSP. The results were negative.
5. Exprimed sperm from tail of epididymis didn't show fluorescence after treatment with cor­ respondent antibodies. However washed ejaculated sperms had a distinct fluorescence in the middle piece. After incubation of washed sperms with BBSP containing seminal plasma the entire surface of the sperms showed an additional immunofluorescence.
6. From this it is concluded that BBSP develops or is concentrated in the middle piece of sperms during its stay in the head of the epididymis. During the ejaculation a portion of the sperms is destroyed and therefore BBSP enters the seminalplasma. The sperms contain on the whole surface strongly negatively charged groups especially neuraminic acids. The BBSP binds to these groups. So the electrophoretic mobility of ejaculated sperms is reduced.
7. The BBSP has a strong leukotactic activity. This is the probable reason for the phagocytotie activity of seminal plasma.
Stabilities of Vanadyl Complexes with Methionine, Phenylalanine, and Threonine
Authors: Sekhon B.S. , Chopra S.L. 
Published: August 2018

Abstract
Stepwise formation constants corresponding to 1:1 vanadyl complexes with methionine, phenylalanine and threonine have been determined at 25 °C, and at various ionic concentrations, viz. 0.01, 0.1 and 0.3 ᴍ , maintained by the addition of potassium chloride solution. Thermodynamic stability constants have been obtained by extrapolation of log K values to zero ionic strength. Logarithms of the overall stability constants (log K (u = 0)) are 7.72 for methionine, 7.70 for phenyl­alanine and 7.44 for threonine complexes. The corresponding free energy changes (⊿G0) are - 10.53, - 10.51, - 10.15 kcal-mol-1 respectively.
Über den Abbau von Chalkonen und Isoflavonen in pflanzlichen Zellsuspensionskulturen / Degradation of Chalcones and Isoflavones in Plant Cell Suspension Cultures
Authors: Berlin Jochen , Kiss Peter , Müller-Enoch Dieter , Gierse Dieter , Barz Wolfgang , Janistyn Boris 
Published: August 2018

Abstract
Cell suspension culture of Phaseolus aureus, Glycine max and Pisum sativum have been used to determine the extent of chalcone and isoflavone catabolism.
The A-rings of calcones and isoflavones with both resorcinol and phloroglucinol pattern of sub­stitution have unequivocally been shown to be degraded as measured by carbon dioxide production The earlier described catabolic pathway of chalcones with the B-ring liberated as a substituted benzoic acid has been verified using another chalcone.
With the use of various 14C-labelled isoflavones it could be demonstrated that essentially all carbon atoms are introduced into catabolic reactions.
Incorporation of 4',7-dihydroxyisoflavone (daidzein) into insoluble polymeric material has been shown to proceed via the 3',4',7-trihydroxyisoflavone. 3'-Hydroxylation and subsequent polymeri­sation of the orto-dihydroxy compound can completely be inhibited by using anaerobic conditions which favour glucoside formation instead. 4'-O-Methylgroups in isoflavones prevent the phenolase catalzyed 3'-hydroxylation and thus the incorporation of isoflavones into polymeric structures. 6,7-Dihydroxy substituted insoflavones when fed to cell cultures are not polymerized by phenolase but are rather converted to glycosides.
Secondary Ion Microanalysis of Fluorine in Apatites of Biological Interest
Authors: Petersson L.G. , Frostell G. , Lodding A. 
Published: August 2018

Abstract
A Cameca IMS 300 ion analyzer has been used to measure fluorine concentrations in tooth material. Samples of human and shark teeth were studied. Negative oxygen primary ions produce secondary mass spectra in which positive as well as negative fluorine ion peaks are well re­ presented. With constant measuring conditions, the reproducibility of the F/Ca ion ratios is satisfactory. Fluorine concentrations in the 10 ppm region are easily recorded. By means of samples previously measured by macroscopic F-determining methods, a calibration can be effected to obtain, from the ion current ratios, at least semiquantitative values of F-concentrations.
In a sample of human enamel, the F-concentration was found to vary from about 3000 ppm at the surface to about 100 ppm in the interior. In shark enamel the composition at the surface cor­ responded to nearly saturated fluorapatite, 3.6% F, but the fluorine concentration decreased distinctly at increasing depth.