bluuebunny/crossref_metadata_2025 huggingface dataset:
Cooperative Effects in Aminothiols: Acid-Base Equilibria and the Molecular Structure of 2-(N, N-Dimethylaminomethyl)thiophenol
Authors: Fleischer Holger , Schollmeyer Dieter
Published: August 2018

2-(N,N-Dimethylaminomethyl)thiophenol, (1, HL), is present as a non-zwitterionic aminothiol in the solid state, exhibiting an intramolecular S-H···N hydrogen bond. The S···N distances of the two independent molecules in the asymmetric unit are 2.929(10) and 3.050(10) Å. This structural feature is also present in an ab initio (MP2/6-31G*) optimized molecular structure. The investigation of the hydrogen bond by ab initio methods supports an n(N)-σ *(S-H) interaction as the reason for this bond type. On the basis of data from potentiometric acid-base titrations of a 0.01 M aqueous solution of [H2L]Cl with a 0.1 M aqueous solution of sodium hydroxide, values of 4.09±0.01 and 11.50±0.01 were obtained for pKa1 and pKa2 of [H2L]+. pKa1 is much smaller than pKa of thiophenol while pKa2 is bigger than pKa of benzyldimethylamine. The increased difference between pKa1 and pKa2 is attributed to the stabilization of HL by the intramolecular S-H···N hydrogen bond.
Influence of Hydrogen Bonding Interactions on the Conformation of Ribbon-like Zn(II) Complexes Bridged by Molybdates
Authors: Hua Tianhui , You Wansheng , Daia Limei , Zhao Yi , Fang Yong , Zheng Xuefang
Published: August 2018

The complexes [Zn(dpa)MoO4] (1) and [Zn(dpa)MoO4]·0.5H2O (20.5H2O) (dpa = 2,2'-dipyrid- ylamine) were synthesized hydrothermally. Single crystal structure analyses indicate that 1 and 2 are conformational isomers. They both consist of binuclear units of edge-sharing {ZnN2O3} trigonal bipyramids bridged by pairs of bidentate briding {MoO4}2- anions into a one-dimensional ribbon, but their orientations of the terminal O atoms of the {MoO4}2- anions are different. In 1 and 2, the ribbon-like chains are connected into a 2D network via hydrogen bonding interactions between the central N-H portions of the dpa molecules and the terminal O atoms of {MoO4} tetrahedra. For 2, in addition, the hydrogen bonding interactions between the crystal water molecules and the terminal O atoms of {MoO4} tetrahedra join the 2D layers into a 3D architecture. They play an important role not only in constructing the 3D architecture, but also in the conformational stability.
Convenient Synthesis and Evaluation of Biological Activity of Benzyl (2S)-2-[(R)-1-hydroxy-2-oxo-(1-phenethyl)prop-3-ylcarbamoyl]- 4-oxopiperidine- (or -4-oxopyrrolidine)-1-carboxylate as Novel Histone Deacetylase Inhibitors
Authors: Oh Seikwan , Moon Hyung-In , Jung Jae-Chul , Avery Mitchell A.
Published: August 2018

A simple synthesis, involving a key coupling reaction, and the biological activity of the title compounds 16 and 17 are described. The key fragments are the amine·HCl salt 6 and the acids 9 and 13, which were smoothly coupled by using ethyl(dimethylaminopropyl)carbodiimide (EDCI) and 1- hydroxybenzotriazole (HOBt) in high yield.We have found that the in vitro growth inhibitory potency of the new compounds 16 and 17 exhibits good histone deacetylase (HDAC) activity.
Pentacyclic Triterpenes and Other Constituents from Ficus cordata (Moraceae)
Authors: Poumale Herve M. P. , Kengap Rodrigue T. , Tchouankeu Jean Claude , Keumedjio Felix , Laatsch Hartmut , Ngadjui Bonaventure T.
Published: August 2018

Two new pentacyclic triterpenes 8,26-cyclo-urs-21-en-3β, 20β-diol (1) and 3β-acetoxy-8.26- cyclo-ursan-20β-ol (2) together with 3-friedelanone, oleanolic acid, betulinic acid, lupeol acetate, α- and β-amyrine, S.SJ^'-tetrahydroxyflavane, and 3,5,7,3',4'-pentahydroxyflavane were isolated from the stem bark of Ficus cordata (Moraceae). The structures of these secondary metabolites were established using ID and 2D NMR spectra and by comparison with published data or with authentic samples. Compounds 1 and 2 exhibited weak antibacterial and no antifungal activity.
Structural Studies of Some o- and p-Nitrophenylcarbamates by IR Spectroscopy and X-Ray Diffraction
Authors: Simon Monika , Csunderlik Carol , Jones G.
Published: August 2018

N-Alkyl-o-nitrophenylcarbamates as solids present two carbonyl stretching bands in the region 1700 - 1800 cm−1 but similar N-alkyl-p-nitrophenylcarbamates have only one such band in the IR spectrum. In solution both kinds of carbamate present one carbonyl stretching band, but for the former, the splittings occur when the carbamates crystallize. Four crystal structures were analyzed by X-ray diffraction. The two ortho derivatives have more than one molecule in the asymmetric unit, which is consistent with the IR observations.
Study on Chemical Constituents of Salacia chinensis L. Collected in Vietnam
Authors: Minha Tran Thi , Anh Nguyen Thi Hoang , Thanga Vu Dao , Sung Tran Van
Published: August 2018

A new triterpene, 28-hydroxy-3-oxo-30-lupanoic acid (1), and a triterpene found for the first time as a natural product, 3-oxo-lupane-30-al (2), besides three known triterpenes, 29-nor-21α-H-hopane- 3,22-dione (3), 21α-H-hop-22(29)-ene-3β , 30-diol (4), and betulin (5) have been isolated from the n-hexane extract of Salacia chinensis stems. Their structures were elucidated on the basis of spectral studies.
5-Aminouracil as a Building Block in Heterocyclic Synthesis: Part I. One-pot Synthesis of Pyrimido[5,4-b]quinolin-2,4,9-triones under Microwave Irradiation without Catalyst
Authors: Shaker Raafat M. , Elrady Mohamed Abd
Published: August 2018

A series of 6,7,8,10-tetrahydropyrimido[5,4-b]quinolin-2,4,9-(1H,3H,5H)-triones 6 were synthesized through one-pot condensation of 5-aminouracil, aldehydes and dimedone in DMF under microwave irradiation without catalyst. The products 6a, d were oxidized to the 7,8-dihydro-pyrimido- [5,4-b]quinolin-2,4,9-(1H,3H,6H)-triones 11a, b. Treatment of 6a, d and/or 11a, b with ethyl iodide in the presence of anhydrous potassium carbonate gave the ethylated derivatives 12a, b and 13a, b, respectively. The structures of the products were confirmed by elemental analyses, IR, MS, 1H, and 13C NMR spectra.
Enzymatic Resolution of (±)-2-Exo-7- syn-7-(1-propynyl)norbornan-2-ol, a Key Synthetic Intermediate for Jasmonoids
Authors: Kiyota Hiromasa , Nakashima Daisuke , Kuwahara Shigefumi , Oritani Takayuki
Published: August 2018

Lipase-catalyzed resolution of 2-exo-7-syn-7-(1′-propynyl) norbornan-2-ol, a key synthetic intermediate for jasmonoids, was achieved using vinyl chloroacetate as an acyl donor.
Rare Earth-Transition Metal Indides with Lu5Ni2In4-type Structure
Authors: Zaremba Roman , Hermes Wilfried , Eul Matthias , Pöttgen Rainer
Published: August 2018

New intermetallic compounds RE5T2In4 (RE = Sc, Y, La-Nd, Sm, Gd-Tm, Lu; T = Rh, Ir) were synthesized by arc-melting of the elements or by induction melting of the elements in tantalum crucibles under flowing argon. The samples were characterized by X-ray powder diffraction. They crystallize with the orthorhombic Lu5Ni2In4-type structure, space group Pbam, Z = 2, a 2 : 1 intergrowth variant of CsCl and AlB2 related slabs of compositions InRE8 (distorted cubes) and RhRE6 (distorted trigonal prisms). Susceptibility measurements of Ce5Ir2In4 have revealed modified Curie- Weiss behavior above 70 K with an experimental magnetic moment of 2.45(1) μB / Ce atom. The cerium magnetic moments order ferri- or ferromagnetically at TC = 7.1(2) K.
The acidic ionic liquid [BSO3HMIm]HSO4: a novel and efficient catalyst for one-pot, three-component syntheses of substituted pyrroles
Authors: Luo Yuan , Zhang Bao-Qiang , He Yan-Hong , Guan Zhi
Published: August 2018

An acidic ionic liquid 3-methyl-2-(1-sulfobutyl)-1H-imidazolium hydrogensulfate, [BSO3HMIm]HSO4, was used as an efficient catalyst for the synthesis of a variety of pyrrole derivatives via a one-pot, three-component condensation of amines, nitroolefins, and 1,3-dicarbonyl compounds. Good to excellent yields of 72–96% were obtained under reflux in ethanol. The catalyst could easily be recovered and recycled up to six times, resulting in good yields without prolonging the reaction time. This method was also efficient in large-scale preparation. The procedure could be easily expanded to a one-pot, four-component reaction. This ionic liquid-catalyzed reaction provided an environmentally friendly alternative to the synthesis of pyrrole derivatives.
Synthesis and structural characterization of substituted phenols with a m-terphenyl backbone 2,4,6-R3C6H2OH (R=2,4,6-Me3C6H2, Me5C6)
Authors: Şolea Atena B. , Olaru Marian , Silvestru Cristian , Raţ Ciprian I.
Published: August 2018

Substituted phenols with a m-terphenyl backbone 2,4,6-R3C6H2OH [R=2,4,6-Me3C6H2 (1), Me5C6 (2)] were synthesized using Kumada cross-coupling reactions between 2,4,6-I3C6H2OH and the corresponding Grignard reagent. Both compounds were structurally characterized in solution by 1H and 13C NMR spectroscopy and HRMS. The molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction.
“Naked” S2O7
2– ions – the serendipitous formation of the disulfates [HPy]2[S2O7] and [bmim][HPy][S2O7] (HPy = pyridinium; bmim = 1-Butyl-3-methylimidazolium)
Authors: Bruns Jörn , Logemann Christian , Weiz Alexander , Kolb Claudia , Wickleder Mathias S.
Published: August 2018

[bmim][HPy][S2O7] [monoclinic, P21/n, Z = 4, a = 825.78(2), b = 1545.30(3), c = 1410.80(3) pm, β = 104.726(1)°, V = 1741.16(7) Å3] was obtained as a side product in the reaction of GeCl4, oleum (65% SO3), and the pyridine (Py) complex Py·SO3 in the ionic liquid 1-butyl-3-methylimidazolium hydrogensulfate, [bmim][HSO4], at 50 °C. Charge compensation of the disulfate ion is achieved by the counterions pyridinium, [HPy]+, and 1-butyl-3-methylimidazolium, [bmim]+. The crystal structure shows alternating layers of [bmim]+ cations on one hand and [HPy]+ cations and disulfate anions on the other hand. Pyridinium disulfate, [HPy]2[S2O7] [orthorhombic, P212121, Z = 4, a = 801.35(1), b = 1257.62(2), c = 1357.22(3) pm, V = 1367.80(4) Å3] was formed unexpectedly in the reaction of Eu2O3 and Py·SO3 in pyridine. The crystal structure exhibits a layer-like arrangement of disulfate and pyridinium moieties in the ab plane. In both compounds, the disulfate groups are essentially uncoordinated allowing for a detailed inspection of “naked” S2O7
2– ions.
New transition metal-rich rare-earth palladium/platinum aluminides with RET
5Al2 composition: structure, magnetism and 27Al NMR spectroscopy
Authors: Benndorf Christopher , Stegemann Frank , Eckert Hellmut , Janka Oliver
Published: August 2018

REPd5Al2 compounds with RE = Ce–Gd as well as Y and Lu have been previously synthesized. Although some compounds with the small lanthanides also exist, the compounds with intermediate-sized rare-earth elements (RE = Tb–Yb) had not been prepared. We report on the missing members of the REPd5Al2 (RE = Tb–Yb) series as well as on the new REPt5Al2 (RE = Y, Gd–Tm, Lu) series, which we have synthesized and structurally as well as magnetically characterized. All members crystallize isostructurally in the ZrNi2Al5 type with an anti-arrangement of the T = Pd/Pt and Al atoms. YPd5Al2 and LuPd5Al2, as well as the respective platinum homologs, YPt5Al2 and LuPt5Al2, have been characterized also by 27Al magic-angle spinning nuclear magnetic resonance spectroscopy. Consistent with the XRD analysis, the spectra indicate the existence of only one distinct Al site in the structure.
Reactions of Antisera to Lutein and Plastoquinone with Chloroplast Preparations and their Effects on Photosynthetic Electron Transport
Authors: Radunz Alfons , Schmid Georg H.
Published: August 2018

An antiserum to lutein inhibits photosynthetic electron transport between water and potassium ferricyanide in diloroplasts from green Nicotiana tabacum var. John William’s Breadleaf. However, electron transport between diphenylcarbazide and potassium ferricyanide is not impaired. From this it is concluded that the photochemically active carotenoid should feed its electrons into the photosynthetic electron transport chain before the site from which diphenyl-carbazide donates electrons. The inhibition of the ferricyanide Hill reaction in diloroplasts by antibodies to lutein depends on the accessibility of the carotenoid antigen in the thylakoid membrane. In fresh preparations the accessibility is greater in diloroplasts in which photo- synthetic electron transport is coupled to photophosphorylation. Concomitantly the antiserum to lutein agglutinates only such chloroplast preparations in which the Hill reaction is impaired by the antiserum.

An antiserum to plastoquinone inhibits ferricyanide photoreduction of diloroplasts regardless whether driven by water or diphenylcarbazide as the electron donors. Typical photosystem-I-reactions are not influenced by the antiserum. In a certain type of chloroplast preparations the antiserum does not inhibit PMS-mediated photophosphorylation inferring that plastoquinone, eventually involved in this reaction, is either not accessible to antibodies, or that this cyclic electron flow does not necessarily pass through plastoquinone.
Dihydrokaempferol as Precursor for Catechins in the Tea Plant
Authors: Zaprometov Michail N. , Grisebach Hans
Published: August 2018

The incorporation of [G-3H]-dihydrokaempferol into catechins o young tea shoots Camellia sinensis L.) was compared with that of ʟ-[U-14C]-phenylalanine and [U-14C]-shikimic acid. The percent incorporation of all three precursors into (-)epicatechin was about equal, whereas the incorporation of shikimic acid into the galloylated catechins was somewhat higher than that of phenylalanine and dihydrokaempferol. From the results it can be concluded that dihydro­ kaempferol is a precursor for catechins in the tea plant.
Untersuchung der longitudinalen Kernspinrelaxation in konzentrierten Lösungen von Heringsspermien - DNA zur Frage des an DNA gebundenen Wassers / Spin-Lattice Relaxation in Concentrated Solutions of Hering-Sperm DNA and the Problem of Water Bound to DNA
Authors: Daniels A.
Published: August 2018

Proton and Deuteron spin - lattice relaxation have been measured in aqueous solutions of herring sperm DNA as a function of concentration, temperature, and NMR frequency. We find a minimum if the increment of the relaxation rates, 1/T1-1/T1 (free solvent) is plotted as a function of the inverse temperature. The result can be understood by assuming a superposition of two exchange processes: a very rapid exchange of water molecules causes the rate increment at lower temperatures whereas the frequency dependent rate increment in the high temperature region is caused by slow exchange of bound water molecules or DNA protons. The correlation time or the exchange time of the fast exchanging water molecules is smaller than 10-9 s at 4 0C with an activation energy of 7.2 kcal/mole, whereas the slowly exchanging water molecules or DNA protons have at the same temperature a correlation time of more than 10-7 s with an activation energy of 9,8 kcal/mole and an exchange time of 1 s with an activation energy of 11.5 kcal/mole.
Reactions of Retinals in a Model Membrane System
Authors: Brody Seymour S.
Published: August 2018

Monomolecular films of 9-cis, 11-cis, 13-cis and all-trans retinal were formed at an air-water interface. Area/molecule and surface potential were measured before, during and after illumination. The initial quantum yield of the photoisomerization of 9-cis retinal was 0.25. Irradiation of a retinal monolayer resulted in 30 to 60 mVolt changes in surface potential. Complexation of retinals with lysine and cysteine were studied.
Heterogeneity of the Native Ribosomal Subunit Fraction in HeLa Cells
Authors: Lecou Christian , Arends Sigrid , Liautard Jean-Pierre , Köhler Kurt
Published: August 2018

The cytoplasm of growing HeLa cells contains a certain quantity of native ribosomal subunits. They constitute a heterogeneous fraction consisting of at least two categories of particles.

The first category comprises the newly emerging native 40S subunits which do not form 80S couples under any in vitro condition tried. It is postulated that these native subunits carry an anti-association factor which cannot be stripped off by 0.5 м KCl treatment.

Transiently native subunits of the second category reassociate to 80S ribsomes only in the presence of an association factor.
Purification and Properties of the RNA Polymerase-Template Complex of an Influenza Virus
Authors: Schwarz Ralph Τ. , Scholtissek Christoph
Published: August 2018

The enzyme-template complex of influenza RNA polymerase (fowl plague virus) was purified 200-fold. The sole virus component found in this preparation was RNP-antigen. All attempts to remove the internal template led to an irreversible loss of enzyme activity. The complex was essentially free of nucleases. It synthesized exclusively viral minus strand RNA and was unable to initiate more than one cycle of RNA synthesis. The lag phase at the beginning of RNA synthesis in vitro, present in crude enzyme preparations, was abolished with the purified complex. The enzyme was sensitive to sulfhydryl reagents and it was able to accept α-S-ATP in place of ATP.
Mode of Replication and Temperature Characteristics of the RNA Polymerase of an Influenza Virus in vitro
Authors: Paffenholz Volker , Scholtissek Christoph
Published: August 2018

While the enzyme template complex of fowl plague virus (FPV) polymerase is rather stable during incubation in vitro, some of the newly synthesized RNA is degraded rapidly. At low temperatures a pronounced lag phase of RNA synthesis occurs, which can be prevented by incubation with substrate. The in vitro products are initially single-stranded RNA, which are converted to partially double-stranded molecules by phenol and SDS. The results are compatible with an open replicative intermediate structure, in which the newly synthesized RNA is bound to the complementary template only over a rather short region at the growing point.

A comparison of the temperature characteristics of the RNA polymerases of the highly virulent FPV with that of the low pathogenic virus N revealed that the lag phase is a virusspecific property. There appears to exist a correlation between virulence and heat stability of this enzyme, the activity of which is rate limiting at the normal temperature of the host (41 °C).
A Multivariate Analysis of Ca-DTPA-Effectiveness in Removing 241Am from the Rat
Authors: Seidel A.
Published: August 2018

The dependence on time of the dose-effect relationship was studied for the removal of 241Am from the skeleton and liver of the rat by Ca-DTPA . Due to the linearity of the dose-effectcurves (in a log-log scale) as well as to the linear dependence of the slope on the logarithm of time, simple equations were derived which describe the mobilization of 241Am as influenced by DTPA-dosage and time of treatment.
Radioprotection (UV-and Gamma-rays) of DNA Molecule by Indole and Indole-derivatives
Authors: Tomicic I. , Pieber M. , Romero C. , Soto A. , Tohá J. C.
Published: August 2018

The radioprotective ability of ʟ-tryptophan, tryptamine, 3-indoleacetic and indole (10-4 ᴍ), on UV and gamma irradiated DNA (10-4 ᴍ) is studied.

UV radioprotection is accomplished in the following order of efficiency: ʟ-Tryptophan and 3-indoleacetic acid > indole and tryptamine. The corresponding DRF measured as absorbancy loss at 260 nm, were: ʟ-Tryptophan and 3-indoleacetic acid around 3 and tryptamine and indole around l. When absorbancy loss plus changes in the patterns of the absorbancy curve were con­ sidered the DRF was: L-Tryptophan 2.53, 3-indoleacetic acid 1.54, indole 1.22 and tryptamine 0.75, respectively.

For gamma radiation damage the order of radioprotection found was: Indole, ʟ-tryptophan and tryptamine > 3-indoleacetic acid. The DRF when compairing the absorbancy loss at 260 nm, were: ʟ-Tryptophan, Indole and tryptamine around 11 and 3-indoleacetic Acid around 4. When evaluating total changes in absorbancy the DRF were: Indole and ʟ-tryptophan around 6.5, tryptamine 3.7 and 3-indoleacetic 2.1.

These data were correlated with measurement of the degree of molecular interactions of DNA and protectors, studied by: Spectrophotometry, m.p. determinations, circular dichroism and oriented circular dichroism, viscosity, and rate of dialysis. Also data of fluorescence and phosphorescense were considered.

For gamma radioprotection a mechanism based in radical trapping, local radical trapping and partial recovery of radioprotectors is proposed.

UV radioprotection is discussed considering: The close interaction of L-tryptophan with DNA which might impede dimer formation, its proton and electron donor ability. A possible (triplet-triplet) energy transfer from excited DNA to indole derivative is discussed on the basis of acetone competition and a dimer excision process considered.
Der Verlauf der Lipochinon- und Pigmentsynthese bei einer experimentell induzierten Chloroplastendegeneration in grünen Keimlingen von Hordeum vulgare L. / Kinetic of Lipoquinone and Pigment Synthesis during an Experimentally Induced Chloroplast Degeneration in Green Seedlings of Hordeum vulgare L.
Authors: Grumbach K. H. , Lichtenthaler H. K.
Published: August 2018

Within a dark period of 24 hours green Hordeum plants change their lipoquinone and carotenoid metabolism to that of etiolated plants. A longer darkness induces degeneration of chloroplasts with a concomitant destruction of pigments and lipoquinones which is similar to that of the natural chloroplast degeneration in leaves.

1. The chlorophyll and vitamin Kt content is not augmented in the dark, but decreases. The concentration of the oxidized benzoquinones plastoquinone-9 and α-tocoquinone decreases rapidly whereas the level of plastohydroquinone-9 is augmented until 24 hours darkness. α-Tocopherol in turn is accumulated throughout the dark period.

2. Among the carotenoids β-carotene is considerably enriched only in the first 24 hours of the dark period. Xanthophylls are accumulated up the 3 days. The successive increased appearance of single carotenoids during the dark period corresponds to their biogenetic sequence. During carotenoid breakdown (after the 3rd day) neoxanthin, as common oxidation product of all carotenoids appears as the main carotenoid component.

3. It is postulated that the accumulation of the reduced quinone forms (α-tocopherol, plastohydroquinone- 9) in the dark, which has been shown here, also occurs in the dark phase during natural day-night growth of plants and thus gives rise to the continuous accumulation of a-tocopherol and plastohydroquinone-9 in chloroplasts, as described before 4.
Methylation of Deoxyribonucleic Acid in Regenerating Rat Liver
Authors: Lutz Dieter , Grahn Helga , Kröger Hans
Published: August 2018

In double label pulse experiments DNA methylation was compared to DNA synthesis after partial hepatectomy. 24 hours after the operation the highest 14C-thymidine incorporation rates were found as well as the highest 5-methylcytosine labelling derived from (3H-methyl) -methionine. However, synthesis was much more elevated than DNA methylation. Applying Endoxan DNA methylation is reduced to a significantly higher extent than DNA synthesis. Our results indicate that DNA methylation occurs not only combined with DNA synthesis.
Gaschromatographisch-massenspektrometrische Differenzierung von Erdbeerarten / Gaschromatographical-masspectrometrical Differentiation of Aroma Substances from Strawberries
Authors: Drawert Friedrich , Tressl Roland , Staudt Günter , Köppler Hans
Published: August 2018

Ripe fruits of wild growing varieties of strawberries had been homogenized under inhibition of the enzymes and extracted with the adding of an internal standard. About 40 main components could be identified and quantitatively determined by gaschromatographical-mass-spectrometrical investigations. Methyl ketones and secondary alcohols dominate in Fragaria moschata and Fragaria vesca, whereas especially ethylesters of the carboxylic acids C6 to C12 are formed by Fragaria chiloensis. Fragaria virginiana contains numerous components amongst which are especially the methyl-and ethylesters of the carboxylic acids C6 to C12; besides it contains, as distinctive marks, n-butyl-, n-hexyl, ra-octyl, and n-decylesters of the carboxylic acids C4 to C10 . All varieties exhibit a sorttypical distribution pattern of the aroma components.
Zur Thermodynamik der hydrophoben Wechselwirkung; die Systeme Wasser + Glycin+ Harnstoff und Wasser + Alanin+ Harnstoff bei 25 °C / Thermodynamics of Hydrophobie Interaction in the Systems Water + Glycin + Urea and Water + Alanin + Urea at 25 °C
Authors: Rafflenbeul Lothar , Pang Wa-Ming , Schönert Hansjürgen , Haberle Klaus
Published: August 2018

Isopiestic vapor pressure measurements and calorimetric determination of the heat of dilution have been performed and evaluated with respect to enthalpy, entropy and free enthalpy in the ternary solutions water+ glycin+ urea and water+ alanin + urea. The free enthalpy of transfer for the process: Amino acid from water to water+ urea, which can be derived from these measurements, does not agree with the value calculated from solubility measurements. The reason for this discrepancy and the values of entropy and enthalpy in terms of hydrophobic interaction are discussed. Supplementary measurements of the proton magnetic resonance in these solutions are included.
Nicht methylenunterbrochene cis,cis-Octadecadiensäuren Minor Constituents of Human Milk, VI Non Methylene Interrupted cis,cis-Octadecadienoic Acids
Authors: Murawski Uwe , Egge Heinz , György Paul , Zilliken Fritz
Published: August 2018

The non methylene interrupted cis,cis-octadecadienoic acids from human milk fat were pre­pared by thin layer chromatography on AgNO3 impregnated silicagel plates. The position of double bonds was determined by hydroxylation of the double bonds with OsO4 followed by silylation. The corresponding O-trimethylsilylether derivatives of the fatty acid methyl esters were analyzed by gaschromatography mass spectrometry. 14 isomers of the following series could be identified: C18:2 ⊿9. (12.13.14.15.16.17) ; C18:2 ⊿ (6.7.8.9.).12; C18:2 ⊿ (10.11.12.).15 (⊿18.15) ; C18:2 ⊿5.9-, ⊿6.10; ⊿10.14; (⊿12.16). Possible biosynthetic pathways are discussed.
Evidence for the Validity of Three-Component Fitting of Protein Circular Dichroism Spectra
Authors: Bannister W. H. , Bannister J. V.
Published: August 2018

The validity of three-component fitting of protein circular dichroism (CD) spectra in the peptide absorption region with basis spectra for helical, β-sheet and unordered structure is examined by matrix rank analysis of protein CD spectra. It is shown that a three-component basis can be justified for several proteins within the limits of experimental error of the spectra. It is suggested that the fitting of protein CD spectra with basis spectra derived from reference proteins should be preceded by matrix rank analysis to show that the CD spectra of the reference and unknown proteins have the same basis.
Identification of Radiolysis Products of Cytosine Resulting from the Deamination Pathway
Authors: Polverelli M. , Teoule R.
Published: August 2018

Radiolysis products resulting from the deamination pathway were isolated and identified after irradiation of cytosine by gamma rays in neutral aqueous solutions. They were identical to those identified in uracil radiolysis i. e. 5,6-dihydroxy-5,6-dihydro-uracil (cis and trans forms), iso-dialuric acid, alloxan, 5-hydroxy-hydantoin, parabanic acid and oxaluric acid.

The absence of 4,4′-di-iso-barbituric acid, alloxantin or iso-barbituric acid could be explained by the good stability of uracil glycols. The identification of buiret proof of potential degradation mechanisms different from these involving of the free radical attack on the 5,6 double bond. Gamma Irradiation of Cytosine in an Aerated Aqueous Solution, I
Die radioaktive Markierung des Melaninpigments der Fischhaut mit [35S]Natriumsulfat Radioactive Labelling of the Melanin Pigment in Fish Skin with [35S] Sodium Sulphate
Authors: Plesse Dieter , Lüdicke Manfred
Published: August 2018

[35S]Sodium sulphate was intraperitoneally injected into adult fishes and its incorporation into melanins examined. Relevant incorporation of the tracer into normal skin and peritoneal melano­ cytes of Poecilia reticulata (Peters) and Puntius tetrazona tetrazona (Hamilton) could be detected only in rare cases. Melanocytes of malignant melanomas in the hybrids of Xiphophorus helleri (Heckel) and Platypoecilus maculatus (Guenther) exhibited a different degree of radioactivity ac­ cording to their degree of differentiation. The isolation of the melano-protein complex from melanocytes of these melanomas and its subsequent hydrolysis resulted in the following: During melanin synthesis, [35S] sulphate had been incorporated into the chromophore group as an ester-sulphate, whereas no significant incorporation of the tracer was found in the protein matrix.
Suggestive Evidence for an Oncorna-Virus-Specific DNA Polymerase from C-Type Particles of Bovine Leukosis
Authors: Dietzschold B. , Kaaden O.R. , Ueberschaer S. , Weiland F. , Straub O. C.
Published: August 2018

Typical C-type oncorna virus particles as shown by electron microscopy have been purified from the supernatant of cultured lymphocytes from bovine leukosis. In the purified C-particle fraction a DNA-polymerase activity was detected. Using several synthetic RNA-or DNA-homopolymers and 70S Friend virus RNA the template response of this bovine leukosis cell particle DNA polymerase was compared with those of feline leukaemia virus DNA polymerase and DNA polymerase from normal bovine lymphocytes. The DNA polymerase detected in the viral preparation of bovine leukosis is suggested to be an oncorna-virus-specific enzyme.
Der Einfluß von 4-Hydroxy-2.3-pentenal (HPE) auf die Vermehrung von Vaccinia-Virus in Hühnerfibroblastenkulturen / Influence of 4-Hydroxy-2,3-pentenale (HPE) on the Multiplication of Vaccinia-virus in Chick-embryo Fibroblast Cultures
Authors: Dostal V. , Schauenstein E. , Kulnigg P. , Schmeller E.
Published: August 2018

The influence of 4-hydroxy-2,3-/rans-pentenale (HPE) on multiplication of Vaccinia virus in chick fibroblast cultures has been investigated. The cytotoxicity of HPE has been estimated by in ­ corporation of [3H] thymidine, [3H] uridine, [3H] leucine and by morphological tests. The greatest influence of H PE was seen after incorporation of [3H] thymidine.

Chick-embryo cultures infected with Vaccinia virus showed a marked increase of DNA synthesis in contrast to the controls. This increase averaged 180% after 16 to 14 hours. HPE 0.05-10_ 3 M caused a reduction of 72% in [3H] thymidine incorporation in virus infected cultures. At the same time virus concentration decreased by 76%. HPE 0.1-10~3 M, a concentration which inhibits the normal cell DNA synthesis by 50%, caused about 90% inhibition in infected cultures; virus m ulti­ plication was 99% inhibited. These findings have been attributed to a selective inhibition of virus DNA synthesis by HPE. and possible mechanisms are discussed.
Charge-Transfer Interactions between Nucleobases and Metal Ions: ESR and Optical Absorption Studies
Authors: Lohmann Wolfgang , Hillerbrand Max , Klenert Max
Published: August 2018

The charge-transfer interaction of different nucleobases with Cu2+ has been investigated by means of ESR and optical absorption studies. It could be shown that cytosine forms the strongest complex. The greatest reduction of Cu2+ (that is, spin concentration) was obtained, however, with adenine. Based on these results the following order for the electron donor strength of the nucleo­bases has been obtained: Ade>Cyt>Thy>Ura.
Studies on Purine-Pyrimidine Hydrogen Bonded Base Pairing by Means of Absorption and Emission Spectroscopy
Authors: Wagner Wanda , Zaborowska Maria , Puzyna Wlodzimierz , Shugar David
Published: August 2018

Procedures are described for measurement of association constants between potentially com­plementary purine and pyrimidine bases by hydrogen bonding in non-aqueous medium by means of absorption and emission spectroscopy. The methods require that one of the two constituents be fluorescent and exhibit a long wavelength absorption band not, or only partially, overlapped by the second constituent. The foregoing has been applied to measurements of the association constants, and other parameters, of hydrogen-bonded complexes of 2-aminopurine with 1-substituted uracil, thymine and barbital in chloroform solution, both in the ground and excited states. It was estab­lished that the 1:1 hydrogen-bonded base pairs 2-aminopurine : 1-cyclohexyluracil and 2-amino­ purine: 1-octylthymine maintain the ground-state equilibrium during the life time of the excited state, whereas for the corresponding pair 2-aminopurine: 1-methylbarbital this equilibrium is per­ turbed on excitation. The influence of N-alkylation of the 2-aminopurine residue on base-pairing with the pyrimidines has also been examined. The results are compared with those obtained by other methods. The specific advantages of the procedures employed, and their possible applications to studies on the behaviour of fluorescent residues in polynucleotides, are discussed.
The Dephosphorylation of Adenosine 5′ -Triphosphate in a Binary and Ternary Zn2+ Complex
Authors: Amsler Peter , Buisson David , Sigel Helmut
Published: August 2018

The dephosphorylation of ATP was characterized by determining the dependence of the first-order rate constant on pH in the absence and presence of Zn2+ and together with Zn2+ and 2,2′-bipyridyl. The Zn2+-accelerated reaction passes through a pH optimum at about 8. The decrease in the rate at higher pH is due to the formation of Zn(ATP) (OH)3-; this species is relatively insensitive towards dephosphorylation. It is concluded that Zn(ATP)2- is the reactive species and that the interaction between N (7) and Zn2+ in this complex is crucial for its reactivity. In the presence of 2,2′-bipyridyl (Bipy) the ternary complex, Zn (Bipy) (ATP)2-, is formed which is rather stable towards dephosphorylation. It is suggested that the described effects of acceleration and inhibition are helpful for understanding the recycled processes in nature.
Mobility of Chloroplast Coupling Factor 1 (CF1) at the Thylakoid Surface as Revealed by Freeze-Etching after Antibody Labelling
Authors: Berzborn Richard , Kopp Friedrich , Mühlethaler Kurt
Published: August 2018

Freeze-Etching Freeze-fracturing and 60 sec deep-etching of isolated chloroplast thylakoid systems exposed large areas of the outer surface (matrix side) of the thylakoids. If the thylakoid systems were first treated with antisera against chloroplast coupling factor 1 (CF1), the 14 nm particles at the outer surface appeared aggregated. Between clusters these particles were absent. Since there is no change in the number of particles/area after treatment with antibodies, it is concluded that the 14 nm particles are mobile within the surface of the thylakoid. The antisera contained only anti­bodies against CF1 ; therefore the 14 nm particles at the outer surface are identified to be CF1 . The implication of a mobile ATP-synthetase (CF1) for the mechanisms of photophosphorylation is discussed.
Studies on the Effect of Diphenylcarbazide in Isolated Chloroplasts from Spinach
Authors: Harnischfeger Götz
Published: August 2018

The influence of diphenylcarbohydrazide (DPC) on electron transport parameters of chloroplasts was studied through the use of hypotonically disintegrated plastids in various states of membrane disarray.

The observation that DPC acts as donator for PS II when the natural source becomes inefficient was confirmed.

Contrary to prior contentions oxygen evolution is not diminished upon addition of DPC.

A definite though transient influence of DPC on the pigment system was detected. At a certain state of structural disarray DPC increases the quantum yield and electron transport efficiency through PS II, while simultaneously decreasing the activity of PS I. The effect is not based on addition or removal of individual pigments to the pigment complexes. The analysis of light inten­sity curves and fluorescence kinetics suggest a better migration of trapped light to open reaction centers.

The results are discussed for possible implications on the analysis of the oxygen evolving system as well as on spillover mechanisms.
Ethylene Production by Isolated Chloroplasts
Authors: Elstner E , Konze J
Published: August 2018

Isolated chloroplast lamellae from spinach or sugar-beet leaves produce ethylene from methylmercaptopropanal (MMP) or 2-keto-4-methylmercaptobutyrate (KMB) in the light. The pH-optimum for ethylene production from M M P is 6.3; ethylene production from KMB has an apparent pH-optimum at about pH 5.

Ethylene formation in red light (90 kerg ·cm -2 -sec-1) from the above substrates is stimulated by ferredoxin and inhibited by either DCMU (10-5 м), ferredoxin together with NADP, catalase, superoxide dismutase or under anaerobic conditions. From the inhibition by either DCMU, NADP or anaerobic conditions it is concluded, that an intact electron transport system from water as electron donor to oxygen as electron acceptor is necessary for ethylene form ation. H2O2 alone does not stimulate ethylene formation from M M P or KMB. Inhibition by both catalase and superoxide dismutase support the view, that ethylene formation from M M P or KMB is driven by the OH-radical, which is formed from H2O2 and the superoxide free radical ion.

The presented data suggest that in addition to ferredoxin another membrane-bound factor is involved in photosynthetic oxygen reduction and ethylene formation. This factor (ORF = oxygen reducing factor) stimulates photosynthetic oxygen reduction in the presence of ferredoxin yielding H2O2, in addition to O2
.- , which is the product of the autooxidation of reduced ferredoxin.

During photosynthetic ethylene formation from MMP or KMB, the production of the OH-radical from H2O2 and O2.- according to

H2O2+ O2
·- → OH·+OH-+O2

(Haber and Weiss, Proc. Roy. Soc. Ser. A 147, 332 [1934], Beauchamp and Fridovich, J. Biol. Chem. 245, 4641 [1970]) seems to be the rate-limiting step.
Isolation and Characterization of Mutants of Saccharomyces cerevisiae Auxotrophic and Conditionally Auxotrophic for 5′ -dTMP
Authors: Brendel Martin , Fäth Wolfgang W.
Published: August 2018

An improved method for isolation of yeast m utants auxotrophic for 5′-dTM P is presented. The procedure employs the two folic acid antagonists am inopterin and sulfanilam ide (SAA). Selectiveness of the procedure depends on concentration of SAA and time of incubation.

44 mutants auxotrophic and 3 conditionally auxotrophic for 5′-dTMP were isolated. All belong to one complementation group. The corresponding gene was designated TMP1. Tetrad dissection revealed its chromosomal nature. TMP1 is not closely linked to the genes ADE2,, LEU1, ARG 4, ILV2, HIS5, LYS1 and the mating type locus. With the centromere-linked genes ARG4 and LEU1 I gene TMP1 exhibited second division segregation frequencies of 0.42 and 0.53 respectively, indicative of centromere-linkage.

Strains auxotrophic and conditionally auxotrophic for 5′-dTM P were all respiratory deficient (petite). Genetical analysis indicates that the petite phenotype is due to loss of the rho factor in cells harbouring either tmp1 or tmp1ts alleles.
Dependence of Potassium Ion and Sodium Ion Exchange on Light in the Crayfish Retina
Authors: Stieve H , Malinowska T , Sonnemann D
Published: August 2018

The exchange (release resp. uptake) of K+, Rb+, and Na+ ions in the isolated retina of the crayfish Astacus leptodactylus with the surrounding medium was measured using flame photometry and radioisotopic techniques.

1. The net release of K+ into a Na+ and K+ free, choline containing medium, as measured by means of flame photometry, is increased by illumination.

2. The release of 86Rb+, used as an indicator for K+, in retinas preloaded with the radioisotope is also increased during the period of illumination.

3. The net release of Na+ into a Na+ and K+ free medium containing choline, as measured by means of flame photometry, is decreased by illumination.

4. The 22Na+ uptake of the retina is increased by illumination. The increase is greater after an illumination period of 20 min than after one of 2 min.

5. The uptake of 22Na+ of the retina in the dark is increased when the retina has been previously poisoned by ouabain.

6. The results of these experiments are in agreement with the assumption that: a. Na+- ions are the main carrier of the inward current causing the depolarizing receptor potential of Astacus photoreceptor cell membranes and b. the repolarization is caused by a corresponding outflow of K+ -ions.
The Effect of the Chronic Administration of D-Amphetamine upon Circadian Changes in Amino Acids in the Pineal and Pituitary Glands of the Rat
Authors: Leonard B. E. , Neuhoff V , Tonge Sally
Published: August 2018

The formation of dansyl derivatives of amino acids, 5-hydroxyindoleacetic acid and histamine and their separation on polyamide plates provided a reliable and sensitive method for studying circadian changes in single pineal and pituitary glands of the rat. There appears to be no cor­relation between the circadian changes in concentrations of these substances in the pineal and pituitary glands.

Chronically administered D-amphetamine altered the circadian rhythms of 5-amino acids in the pituitary, including the putative transmitters taurine, glycine and glutamate; in the pineal gland only the rhythmical changes of lysine and 5-hydroxyindoleacetic acid were affected.
Notizen: Improved 2,4-Dinitrophenylhydrazine, Thin Layer Chromatography Methods for the Determination of Micro- and Macroamounts of Ascorbic Acid
Authors: Navon A. , Levinson H. Z.
Published: August 2018

Microamounts of vitamin C could be readily determined in 20 μl-samples using the 2,4-dinitrophenylhydrazine method together with separation by thin layer chromato­graphy. The condensation reaction was carried out for 5 min at 100 °C on a glass fibre disc. Purification of vitamin C hydrazones was accomplished by repeated separation on TLC plates. An aqueous solution of 65% acetic acid was em­ployed to dissolve the vitamin C hydrazones, providing maxi­mal absorbance at 500 nm. The minimum amount detectable by this method is 0.4 μg of dehydroascorbic acid. The macrodetermination of vitamin C was improved by simpli­fying a previous method and employing 65% aqueous acetic acid as a solvent for the hydrazones.
Notizen: Aktive, rhythmische Ventilation des Geruchs­ organs bei Stachelaalen (Mastacem belidae) /Active, Rhythmical Ventilation of the Olfactory Chamber in Mastacembelid Fishes
Authors: Holl Arthur
Published: August 2018

The mode of the olfactory ventilation in fishes of the family Mastacembelidae - tested experimentally - was found to be of an active type, depending on gill-and mandibular movements as well as on the unique structure of the nasal organ itself. This mechanism (sniffling) con­ditions high performance of olfactory information.
The pH Dependence of the Receptor Potential of the Hermit Crab Photoreceptor
Authors: Stieve H. , Malinowska T.
Published: August 2018

The pH dependence of the receptor potential (ReP) of isolated layers of photoreceptor cells from the hermit crab compound eye (Eupagurus bernhardus L.) was determined. Measurements were performed, using extracellular electrodes, in the range pH 3.5 - 9.5 in three different buffer systems: Tris, glycine, and phosphate.

The amplitude of the ReP was highest at pH 7.5 and decreased in more acidic and more alka­line salines (Fig. 4). Relative to the changes in ReP amplitude, the changes in time course and shape of ReP were small.

Salines of pH other than 7.5 caused an increase of the latent period but decreased the peak amplitude time and the repolarizing phase (t2).

Alkaline salines caused about the same changes in the ReP as acidic salines. The only observed difference was that repolarisation was more strongly influenced by alkaline solutions and that the plateau magnitude was depressed relatively more than the peak magnitude in acidic environments.

Of the three buffers used, Tris had the weakest influence on the ReP and phosphate buffer the strongest. In contrast to the good reproducibility of the experimental results, the reversibility of the pH effects was generally poor; the effects with glycine-buffer were more reversible than those with Tris.
Phytoglykolipide aus den Samen von Pistacia vera L. / Phytoglycolipids in the Seeds of Pistacia vera L
Authors: Imre Zeliha
Published: August 2018

Pistacia vera, Anacardiaceae, Phytoglycolipids. Seeds Two phytoglycolipids (PGL1 , PGL2), which in qualitative composition of their long-chain bases, sugar components and fatty acids show a close similarity with the phytoglycolipids of other plant seeds, were isolated from the pistacchio seeds (Pistacia vera L .) . The saccharid chain contain inositol, glucuronic acid, glucosamin, mannose, galactose and arabinose. The major fatty acids were the saturated 2-hydroxy C22 , C23 and C24 acids; the major long-chain bases were dehydrophyto-sphingosine and phytosphingosine. PGL1 should posses the typical groundstructure of the seed phyto­ glycolipids. PGL2 seems to contain a saccharid chain formed slight differently.
Coumarins from the Seeds of Poncirus trifoliata L
Authors: Guiotto A. , Rodighiero P. , Fornasiero U.
Published: August 2018

The coumarinic components of Poncirus trifoliata seeds were investigated. Two coumarins aurapten and 6-methoxy-7-geranyloxycoumarin were isolated and identified.
Untersuchungen über anthrachinon-glykoside aus Rhamnus frangula L., III. 6-O-(ᴅ-apiofuranosyl)-1.6.8-trihydroxy-3-methyl-anthrachinon, ein neues glykosid (Frangulin B) aus der rinde von Rhamnus frangula L. / Investigations of the anthrachinone-glycosides from Rhamnus frangula L., III. 6-O-(ᴅ-Apiofuranosyl)-1,6,8-trihydroxy-3-methyl-anthrachinone, a New Glycoside (Frangulin B) from the Bark of Rhamnus frangula L.
Authors: Wagner Hildebert , Demuth Günter
Published: August 2018

From the bark of Rhamnus frangula L. by polyamide chromatography a new anthrachinone-glycoside was isolated and structurally elucidated as 6-O-(ᴅ-Apiofuranosyl)-1,6,8-trihydroxy-3-methyl-anthrachinone.
Flüchtige Inhaltsstoffe von Ambrosiakäfern (Coleoptera: Scolytidae), I / Volatile Substances from Ambrosia Beetles, I
Authors: Francke W. , Heemann V. , Heyns K.
Published: August 2018

Ambrosia Beetles, Attractant, Xyloterus 3-Hydroxy-3-methylbutan-2-one was found in equal amounts in the extracts of males and females of three species of ambrosia beetles: Xyloterus domesticus L., Xyloterus signatus F. and Xyloterus lineatus Oliv. The substance may play an important role as an attractant because the concentration is highest in the highly attractive extracts of boring beetles. Two additional compounds, 2,3-dihydroxy-2-methyl-butane and 2-hexanole were identified from X. domesticus extracts.
Trägergebundene Serotoninderivate und Affinitätschromatographie synaptischer Membranproteine / Resin Linked Derivatives of Serotonin and Affinity Chromatography of Proteins Isolated from Synaptic Membranes
Authors: Seela Frank , Wesemann Wolfgang
Published: August 2018

An affinity resin for the isolation of the serotonin receptor from nerve ending membranes was prepared by coupling tryptamine, 5-methoxy-tryptamine or serotonin to CNBr-activated Sepharose 4 B. The tryptamine derivatives, N-6-(aminohexyl)-tryptamines, were obtained by subsequent con­ densation of the corresponding indole derivatives with oxalyl chloride and t-aminocaproamide and reduction with LiAlH4. The 6-aminohexyl-group was used as spacer to link covalently the primary amino-group of tryptamine to agarose. - An extract of membrane proteins isolated from rat brain was resolved on this affinity resin into two fractions as compared with only one fraction using unsubstituted Sepharose 4 B.