bluuebunny/crossref_metadata_2025 huggingface dataset:
Rare Earth-rich Magnesium Compounds RE4PdMg (RE=Y,Sm,Gd) and RE4PtMg (RE = Y, Nd, Sm, Gd)
Authors: Tuncel Selcan , Chevalier Bernard , Pöttgena Rainer
Published: August 2018

The rare earth-rich intermetallic magnesium compounds RE4PdMg (RE =Y, Sm,Gd) and RE4PtMg (RE =Y,Nd, Sm, Gd) were prepared by melting of the elements in sealed tantalum tubes in an induction furnace. These new Gd4RhIn-type compounds were characterized by X-ray powder diffraction. The structures of the gadolinium compounds were refined from single crystal X-ray diffractometer data: space group F4̅3m, Z = 16, a = 1388.1(2) pm, wR2 = 0.0392, 381 F2 values and 20 variables for Gd4Pd1.14Mg0.86 and a = 1387.6(2) pm, wR2 = 0.0519, 409 F2 values, BASF = 0.47(4) and 21 variables for Gd4Pt1.07Mg0.93. The gadolinium atoms build up palladium (platinum) centered trigonal prisms which are condensed via common corners and edges, leading to three-dimensional networks. The magnesium atoms form Mg4 tetrahedra which show slight mixing with the platinum metal.
Crystal Structure Refinements of Ge(tP12), Physical Properties and Pressure-induced Phase Transformation Ge(tP12) ↔ Ge(tI4)
Authors: Wosylus Aron , Prots Yurii , Schnelle Walter , Hanfland Michael , Schwarz Ulrich
Published: August 2018

Single crystals of the modification Ge(tP12) are prepared by compressing semiconductor-grade germanium to pressures above 11(1) GPa and heating to temperatures between 1200(100) and 1500(150) K before a stepwise cooling precedes a complete pressure release. The tetragonal crystal structure of Ge(tP12) is refined by means of single crystal X-ray diffraction data collected at ambient conditions (a = 592.81(2), c = 698.03(3) pm, space group P43212). The atomic arrangement comprising interconnected spiral chains of fourfold symmetry bears a structural similarity to the high-pressure modification S(t I16). High-pressure ambient-temperature powder X-ray diffraction measurements reveal a significant anisotropy of the compressibility compatible with the selected crystal structure description. The determined bulk modulus of Ge(tP12) amounts to 70(1) GPa which is in good agreement with theoretical calculations and similar to experimental values of other four-coordinated germanium allotropes. Ge(tP12) is a diamagnetic semiconductor with χ0 = −3.1(3) ·10−7 emu g−1 and ρ300 K ≈ 6 Ωm at 300 K. At 10.1(3) GPa, the beginning of the formation of Ge(t I 4) indicates the onset of a structural transition. The two-phase region extends up to a maximum pressure of 13.0(5) GPa in the direction of increasing pressures. Upon stepwise decompression, the phase Ge(t P12) is reformed from Ge(t I4) at 9(1) GPa.
A Comparative Study of GaAsO4 Polymorphs: ab initio Calculations on High-pressure Forms
Authors: Arroyo y de Dompablo Elena , Morán Emilio
Published: August 2018

First-principles calculations were performed to compare the relative stability and high-pressure behavior of four different GaAsO4 polymorphs: the ordinary-pressure phase (berlinite, α-quartzlike) and three high-pressure phases: the β -VCrO4-like, the rutile-like and a new hexagonal form, recently discovered and related to rutile.
High-pressure Synthesis, Crystal Structure, and Properties of the First Ternary Zirconium Borate β-ZrB2O5
Authors: Knyrim Johanna S. , Huppertz Hubert
Published: August 2018

The high-pressure phase β -ZrB2O5 represents the first ternary borate in the system Zr-B-O. The compound was synthesized under high-pressure / high-temperature conditions of 7.5 GPa and 1100 °C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single crystal X-ray diffraction data, collected at room temperature. The monoclinic zirconium borate crystallizes in the space group P21/c with the lattice parameters a = 439.04(9), b = 691.2(2), c = 896.8(2) pm, and β = 90.96(3)°. The structure is isotypic to the high-pressure phase β -HfB2O5, which is built up from layers of exclusively corner-sharing BO4 tetrahedra. Between these layers, the cations are coordinated square-antiprismatically by eight oxygen atoms.
One-pot Synthesis of Fused 2-Thiouracils: Pyrimidopyrimidines, Pyridopyrimidines and Imidazolopyrimidines
Authors: Youssif Shaker , Agili Fatmah
Published: August 2018

Several 6-substitued-1-methyl-2,5,7,8-tetrahydro-2-thiopyrimido[4,5-d]pyrimidine-4-ones and ethyl 7-amino-5-aryl-1-methyl-4-oxo-1,2,3,4-tetrahydro-2-thiopyrido[2,3-d]pyrimidines-6-carboxylates were synthesized by treatment of 6-amino-1-methyl-2-thiouracil with primary amines and formalin (40%), and with ethyl 3-aryl-2-cyanoacrylate respectively. 8-Substituted-7-hydroxy-3- methyl-2-thioxanthines were synthesized by the treatment of 6-amino-1-methyl-5-nitroso-2-thiouracil with benzylidene-anilines. Elemental and spectral analyses were performed for the new compounds.
Synthesis of New Methano[1,5]dioxocines via a Domino Reaction of 4-Hydroxy-2H-pyran-2-ones / 4-Hydroxy-2H-chromen-2-ones with Acyclic 1,3-Diketones
Authors: Leutbecher Heiko , Conrad Jürgen , Beifus Uwe
Published: August 2018

New methano[1,5]dioxocines, O-heterocycles with a framework similar to Tröger’s base, were prepared by means of a three-component reaction. The scope of this domino reaction was studied.
Antarones A and B, Two Polyketides from an Endophytic Penicillium antarcticum
Authors: Shiono Yoshihito , Seino Yumi , Koseki Takuya , Murayama Tetsuya , Kimura Ken-ichi
Published: August 2018

Two new polyketides, antarones A and B, were isolated from the endophytic fungus Penicillium antarcticum. Their structures were determined by spectroscopic methods. Their general toxicity and cytotoxicity were evaluated, respectively, by brine shrimp lethality and cytotoxicity assay with human cancer cell lines. Neither antarones A nor B exhibited activity at the concentration of 100 μM.
Synthesis and Crystal Structure of 1,3-Diphenyl-2-ferrocenyl-1,3,2-diazabora-[ 3]ferrocenophane
Authors: Auch Tanja-Corinna , Braunschweig Holger , Radacki Krzysztof , Sigritz Rainer , Siemeling Ulrich , Stellwag Sascha
Published: August 2018

1,1′-Bis(phenylamino)ferrocene reacts with dibromo(ferrocenyl) borane to yield a [3]ferrocenophane. The experimental details as well as the crystal structure of the product are presented.
Purpuracolide: a New Alliacane Sesquiterpene from the Basidiomycete Gomphus purpuraceus
Authors: Jiang Meng-Yuan , Yang Xiao-Long , Fang Li-Zhen , Zhang Ling , Dong Ze-Jun , Liu Ji-Kai
Published: August 2018

A new alliacane sesquiterpene named purpuracolide (1) was isolated from the fruiting bodies of basidiomycete Gomphus purpuraceus. The structure and stereochemistry have been established on the basis of spectroscopic data.
Coordination Behavior of tBu2PH towards [{Rh(μ-Cl)(coe)2}2] (coe = cis-cyclooctene): Crystal and Molecular Structure of [{Rh(μ-Cl)(tBu2PH)2}2]
Authors: Böttcher Hans-Christian , Mayer Peter
Published: August 2018

The reaction of [{Rh(μ-Cl)(coe)2}2] (coe = cis-cyclooctene) with tBu2PH in different solvents in various molar ratios was investigated. Working with a molar ratio of Rh to P = 1 : 2 in heptane overnight afforded [{Rh(μ-Cl)(tBu2PH)2}2] (1) in nearly quantitative yield. Upon tuning the molar ratio (Rh/P) in the range from 1 : 2 to 1 : 0.5, 31P{1H} NMR spectroscopy indicated the formation of [(tBu2PH)2Rh(μ-Cl)2Rh(coe)2] (3) besides the complexes [{Rh(μ-Cl)(coe)(tBu2PH)}2] (cis, 2a; trans, 2b). The constitution of 3 was established by an independent synthesis mixing 1 with [{Rh(μ- Cl)(coe)2}2] or [{Rh(μ-Cl)(cod)}2] (cod = 1.4-cyclooctadiene), respectively, which also yielded [(tBu2PH)2Rh(μ-Cl)2Rh(cod)] (4). Single crystals of 1 have been analyzed by X-ray crystallography (monoclinic, Cc, Z = 8, a = 32.7375(3), b = 11.1294(1), c = 24.5134(3)Å ; β = 106.7228(4)◦; V = 8553.70(15) Å3; T = 200 (2) K).
Syntheses of Substituted Furo- and Pyrano-[2,3-a]carbazoles from 2-Cinnamoyl-1-hydroxycarbazoles
Authors: Sridharan Makuteswaran , Prasad Karnam J.R.
Published: August 2018

Reaction of 2-cinnamoyl-1-hydroxycarbazoles 2a - d, with phenacyl bromide, mercuric acetate and H2O2/NaOH under different reaction conditions yielded 2-benzoyl-3-styryl-furo[2,3-a]carbazoles 3a-d, 2-benzylidene-furo[2,3-a]carbazol-3(10H)-ones 4a - d and 3-hydroxy-2-phenylpyrano- [2,3-a]carbazol-4(11H)-ones 5a - d, respectively.
Rare Earth-rich Cadmium Compounds RE4TCd (T = Ni, Pd, Ir, Pt)
Authors: Schappacher Falko M. , Rodewald Ute Ch. , Pöttgen Rainer
Published: August 2018

New intermetallic compounds RE4TCd (RE = Y, La-Nd, Sm, Gd-Tm, Lu; T = Ni, Pd, Ir, Pt) were synthesized by melting of the elements in sealed tantalum tubes in a highfrequency furnace. They crystallize with the Gd4RhIn-type structure, space group F 4̄3m, Z = 16. The four gadolinium compounds were characterized by single crystal X-ray diffractometer data: a = 1361.7(1) pm, wR2 = 0.062, 456 F2 values, 19 variables for Gd4NiCd; a = 1382.1(2) pm, wR2 = 0.077, 451 F2 values, 19 variables for Gd4PdCd; a = 1363.6(2) pm, wR2 = 0.045, 494 F2 values, 19 variables for Gd4IrCd; a = 1379.0(1) pm, wR2 = 0.045, 448 F2 values, 19 variables for Gd4PtCd. The rare earth atoms build up transition metal-centered trigonal prisms which are condensed via common corners and edges, leading to three-dimensional adamantane-related networks. The cadmium atoms form Cd4 tetrahedra which fill voids left in the prisms’ network.
Cotonoates A and B, New Aromatic Esters from Cotoneaster racemiflora
Authors: Khan Shafiullah , Yasmeen Shazia , Afza Nighat , Malik Abdul , Iqbal Lubna , Lateef Mehreen
Published: August 2018

Phytochemical investigation of the chloroform soluble fraction of the methanolic extract of Cotoneaster racemiflora resulted in the isolation of two new aromatic esters named cotonoates A (1) and B (2) along with the known compound methyl 3,4-dihydroxy-5-methoxybenzoate (3). The structures of the new compounds have been assigned on the basis of spectral analysis including 1D and 2D NMR techniques. Compound 3 shows significant antioxidant and lipoxygenase inhibitory activities.
Ab initio Calculations of Electronic Band Structure and Charge Densities of Zinc Blende-type GaN, BN and Their Solid Solution B0.5Ga0.5N
Authors: Riane Rabah , Matar Samir F. , Hammerelaine Lahcene
Published: August 2018

First principles calculations of the electronic band structures of zinc blende-type GaN and BN and their 1 : 1 mixture B0.5Ga0.5N were carried out within DFT using the augmented plane wave method with both GGA and LDA approximations for the effects of exchange and correlation. Equilibrium lattice constants were determined from the total-energy minimization method. The results are compared with those of previous calculations and with experimental measurements. In agreement with these data, ZB-BN is an indirect (Γ → X) wide-gap semiconductor (4.35 eV) while ZB-GaN has a direct gap of 1.9 eV at Γ . For ZB B0.5Ga0.5N we predict a direct band gap of 3.35 eV. Electron charge densities are computed for the unit cell, and ionicity factors are derived for all systems.
Metal Complexes of Biologically Important Ligands, CLXX [1]. Attachment of Unprotected Aminomonosaccharides and of 1,2-Diaminocyclohexane to Palladium(II) and Platinum(II) through Amino Acid and Peptide Residues
Authors: Ehrenstorfer-Schäfers Eva-Maria , Altman Janina , Beck Wolfgang
Published: August 2018

The reactions of unprotected D-glucosamine with N-coordinated, activated amino acid ester ligands (glycine, diglycine, histidine) of platinum(II) and palladium(II) complexes afford cis- and trans- Cl2Pt(NH2CH2CONHR), trans-Cl2Pt(NH2CH2CONHCH2CONHR)2 and Cl2Pd(histNHR)2 (R = sugar residue) as products. 1,2-Diaminocyclohexane reacts with the activated esters of cis-Cl2Pt- (NH2CH2COOH)2, cis-Cl2Pt(triglyOH)2, cis-Cl2Pt(metOH) and cis-Cl2Pd(histOH) to give dinuclear complexes Cl2Pt[(gly)nNHC6H10NH(gly)n]2PtCl2 (n = 1, 3), Cl2Pt(methNHC6H10NHmeth)- PtCl2 and Cl2Pd(histNHC6H10NHhist)PdCl2.
Electroreduction of Organic Compounds, 36 [1]. Electroreduction of Chlorinated Methyl Benzoates
Authors: Gassmann Jörg , Voss Jürgen
Published: August 2018

The preparative electroreduction of the three methyl monochlorobenzoates, the six methyl dichlorobenzoates, and methyl 2,3,4-trichlorobenzoate in different solvent-supporting electrolytes (SSE) was studied. The rate of the dechlorination, which is the main reaction, is dependent on the substitution pattern. Pronounced regioselectivity is therefore observed in case of the oligochloro derivatives. Hydrogenation of the benzene ring and reduction of the methoxycarbonyl group with formation of a hydroxymethyl group are observed as side-reactions. Quantum chemical calculations on the reaction mechanism were performed. The theoretical results are in accordance with the experimental observations.
Structure, Spectroscopic Study and ab initio Calculations on Third-order Nonlinear Optical Behavior of N-(2-Hydroxy-4-methoxybenzylidene)-3- nitroaniline
Authors: Üver Hüseyin , Karaka§ Aslı , Elmalı Ayhan , Durlu T. Nuri
Published: August 2018

N-(2-hydroxy-4-methoxybenzylidene)-3-nitroaniline (1) has been synthesized and characterized by X-ray diffraction analysis, FTIR and 1H NMR spectroscopy. The maximum one-photon absorption (OPA) wavelengths recorded by quantum mechanical computations using a configuration interaction (CI) method are estimated in the UV region to be shorter than 450 nm, showing good optical transparency to the visible light. We have computed both dispersion-free (static) and also frequency-dependent (dynamic) linear polarizabilities (α) and second hyperpolarizabilities (γ) by using the time-dependent Hartree-Fock (TDHF) method to provide an insight into the microscopic third-order nonlinear optical (NLO) behavior of the title compound. The ab initio calculation results with non-zero values on (hyper)polarizabilities indicate that the synthesized molecule might possess microscopic third-order NLO phenomena.
A Photoluminescent zig-zag 1D Coordination Polymer with Mixed Ligands [Zn(absa)(pcih)](CH3OH)
Authors: Li Dong-Qing , Liu Xing , Zhou Jian
Published: August 2018

A novel 1D zinc(II) coordination polymer [Zn(absa)- (pcih)](CH3OH) (1) (Habsa = 4-aminobenzenesulfonic acid, Hpcih = 2-pyridinecarbaldehyde isonicotinoylhydrazone) has been synthesized by solvothermal reaction at 72 °C and structurally characterized. Each Zn2+ ion is five-coordinated by three N atoms and one O atom from two pcih ligands, and one O atom of an absa ligand, forming a distorted squarepyramidal geometry. Zn2+ ions are bridged by pcih ligands in a zig-zag arrangement generating infinite chains with appended absa ligands. Photoluminescent studies have shown that 1 exhibits an emission at 535 nm (λex = 492 nm).
Synthesis and Crystal Structure of the Bimetallic Complex [Fe(phen)3]2[phen][V4O12]·19H2O
Authors: Xua Xiuhong , Caob Qilin , Luo Fang , Wang Guang
Published: August 2018

A new bimetallic complex, [Fe(phen)3]2[phen][V4O12]·19H2O (1) has been obtained under nonhydrothermal conditions and characterized by single-crystal X-ray diffraction, IR and TG analysis. Crystal data: Fe2V4O31N14C84H94, triclinic, P1̄̄, a = 12.920(5), b = 17.833(5), c = 23.420(5) Å , α = 107.119(5)°, β = 90.643(5)°, γ = 107.643(5)°, Z = 2. In compound 1, water molecules build up 1D chains and decameric rings by hydrogen bonds. The hydrogen bond interactions between decameric rings and 1D chains form a 2D supramolecular sheet with large holes. The [V4O12]4− anions fill these holes. The [Fe(phen)3]2+ cations play a role as charge-compensating and space-filling units. Hydrogen bonding and electrostatic interactions lead to a new 3D supramolecular framework.
Acidic Salts of the Decaoxodiperiodic Acid: NiH4I2O10· 6H2O, ZnH4I2O10· 6H2O andMgH4I2O10· 6H2O; Crystal Structures, Vibrational Spectra and Thermal Decomposition
Authors: Aleksandrova Margarita , Haeuseler Hartmut , Jaquet Ralph , Wagener Michael
Published: August 2018

By crystallization from strongly acidic aqueous solutions, nickel and zinc tetrahydrogen-decaoxodiperiodate hexahydrate, NiH4I2O10·6H2O and ZnH4I2O10·6H2O, have been obtained and found to be isotypic to CuH4I2O10·6H2O (P21/c, no. 14) with the lattice parameters a = 1070.3, b = 544.0, c = 1187.2 pm, β = 112.6° for the Ni compound and a = 1073.3, b = 545.3, c = 1189.5 pm and β = 112.5° for the Zn compound. The crystal structure of MgH4I2O10·6H2O has been reinvestigated and contrary to former results found to be isotypic to the Cu compound as well. IR and Raman spectra are given and analyzed with respect to the internal vibrations of the H4I2O10
2− ion and the hydrogen bonding system. According to high-temperature Raman spectra and DTA and TG measurements, the compounds decompose in the temperature range up to 300 °C via unknown salts with the anions H4IO6
2− and IO4
− to the corresponding iodates. In the case of the Ni compound the exothermic decomposition to the iodate occurs in two steps.
Socotroside, a New Pentacyclic Cucurbitane Glycoside from Dendrosicyos socotrana
Authors: Abdel Halim Osama B. , Marawan El-Sayed M. , El-Gamal Ali A. , Zaghloul Mona G.
Published: August 2018

Phytochemical investigation of the ethyl acetate extract of the stem of Dendrosicyos socotrana Balf. f. resulted in the isolation of a new pentacyclic cucurbitane glycoside Socotroside, in addition to the three known cucurbitacins, dihydrocucurbitacin D, dihydrocucurbitacin F and cucurbitacin G. The structures of the isolated compounds were established on the basis of their spectral data. The isolated cucurbitacin aglycones showed marked cytotoxic activity.
2,5,8-Tri-tert-butyl-1,3,4,6,7,9-hexaazaphenalene: Synthesis, Crystal Structure and Calculation of Homolytic N–H Bond Dissociation Enthalpies
Authors: Jiang Yuqin , Zhanga Huaqiang , Wan Xiangjian , Xue Xiaosong , Liu Yuanhai , Song Haibin , Yu Ao , Chena Yongsheng
Published: August 2018

2,5,8-Tri-tert-butyl-1,3,4,6,7,9-hexaazaphenalene (6) was prepared from diethyl 2-[bis(methylsulfanyl) methylene]malonate (1) in four steps. The structure of compound 6 was confirmed by single crystal X-ray diffraction. The phenalene skeleton is nearly planar, and there is no π-π overlap between the hexaazaphenalene rings. A calculation of the homolytic bond dissociation enthalpy (BDE) was performed for compound 6 and its analogs 7 and 8, and the results were used to explain the different reactivity for these three compounds to form the corresponding radicals.
The influence of alkali-metal ions on the molecular and supramolecular structure of manganese(II) complexes with tetrachlorophthalate ligands
Authors: Wang Hong-Dan , He Ming-Yang , Chen Qun , Chen Sheng-Chun
Published: August 2018

In our efforts to investigate the influence of alkali-metal ions on the formation of metal complexes with polyhalogen-substituted benzenedicarboxylates, two manganese(II) complexes of tetrachlorophthalic acid (1,2-H2BDC-Cl4), [Mn2(1,2-BDC-Cl4)2(H2O)9]·H2O (1) and [MnK2(1,2-BDC-Cl4)2(H2O)4]
n
(2), were synthesized and structurally characterized. Single-crystal X-ray diffraction studies have revealed that complexes 1 and 2 crystallize in space groups P1̅ and Pbcn, respectively. Complex 1 shows a discrete dinuclear structure, while complex 2 features a two-dimensional heterometallic framework containing rare Mn–O–K linkages. The results clearly suggest that the introduction of alkali metal ions does play a critical role in the construction of complexes 1 and 2 with distinct dimensionality and connectivity. Their spectroscopic, thermal, and fluorescence properties have also been studied briefly.
2-Ethyl-1-phenylindazolium hexafluorophosphate. N-heterocyclic carbene formation, rearrangement, ring-cleavage reactions, and rhodium complex formation
Authors: Guan Zong , Gjikaj Mimoza , Schmidt Andreas
Published: August 2018

2-Ethyl-1-phenylindazolium hexafluorophosphate was deprotonated by potassium 2-methyl-butan-2-olate to give the N-heterocyclic carbene of indazole, i.e., indazol-3-ylidene. This N-heterocyclic carbene undergoes a ring transformation to 9-ethylaminoacridine. Trapping of the carbene with sulfur, silver(I) oxide, and carbonylbis(triphenylphosphane)rhodium(I) chloride resulted in the formation of indazolethione, indazolone (X-ray structure analysis), and carbonylbis(triphenylphosphane)(2-ethyl-1-phenyl-1H-indazol-3-ylidene)rhodium(I) hexafluorophosphate (X-ray structure analysis), respectively. Reaction of the indazolium salt with phenolate and thiophenolate gave an N-ethyl-2-(phenylamino)benzimidate and benzimidothioate, respectively.
Hydrometallation of amino-dialkynylgermanes – a gallium hydride oligomer and intramolecular Lewis acid-base interactions
Authors: Uhl Werner , Tannert Jens
Published: August 2018

The compound H5C6(H)Ge[C(GaCMe3)=C(H)CMe3]2(μ-H)3[Ga(CMe3)2], 2, was isolated in trace quantities from the reaction of Et2N–Ge(C≡C–CMe3)3 with excess H–Ga(CMe3)2. Compound 2 has a unique molecular structure with a Ga3H3 heterocycle of which one Ga–H–Ga group is bridged by a dialkenylgermanium unit. The molecular structure of a second compound (3) is reported, which may be described as a spiro-germane and has AlNGeC and AlC2Ge heterocycles. The rings are formed by intramolecular Al–N and Al–C interactions.
Crystal structure of the europium(II) aluminate Eu3Al2O6
Authors: Niehaus Oliver , Pöttgen Rainer
Published: August 2018

Well-shaped single crystals of the europium(II) aluminate Eu3Al2O6 were obtained as a side product during a synthesis attempt for EuCdAl. The structure was refined from single crystal X-ray diffractometer data of a twinned specimen: Ca3Al2O6 type,

P
a

3
¯

,

$Pa\bar 3,$

a
=1584.82(2) pm, wR
=0.0570, 2034 F
2 values, and 103 variables. All aluminium atoms in the Eu3Al2O6 structure show tetrahedral oxygen coordination, and the AlO4 tetrahedra (173–178 pm Al–O) are condensed via common corners to two-dimensional networks. The six crystallographically independent europium sites have coordination numbers 6, 7, 8, and 9, and their europium–oxygen polyhedra are linked with the AlO4 tetrahedra to a dense packing. Bond-valence calculations reveal two sets of differently bonded europium atoms.
Regulation der Chlorophyllbiosynthese. Lidit- und entwicklungsbedingte Aktivitätsänderungen von vier aufeinander folgenden Enzymen der Porphyrin- und Chlorophyllbiosynthesekette / Regulation of Chlorophyll Biosynthesis. Changes in Activity of Four Consecutive Enzymes in the Porphyrin and Chlorophyll Biosynthesis Chain during Development and Illumination
Authors: W. Schneider Hansjörg A.
Published: August 2018

The activities of enzymes related with chlorophyll and porphyrin synthesis have been examined during development and greening of young corn leaves. The enzymes succinyl-CoA-synthetase (SCoAS), δ-amino-levulinate synthetase (ALAS), δ-amino-levulinate dehydratase (ALAD) and the enzymes involved in porphobilinogenase (PBGA) were under investigaton.

When leaves are illuminated and chlorophyll synthesis begins the activity of ALAD is not influenced. The activity of PBGA and SCoAS are slightly higher than in darkness, but the changes are below the range affecting chlorophyll biosynthesis. ALA, however, is only synthetized in the light. Synthesis ceases immediately when illuminiation ist stopped, indicating'that in darkness ALAS is not active. On the other hand ALAS is active in dark grown roots, tubers and other non-leaf tissues.

Feeding the plant with succinate, glycine or α-keto-glutarate has no effect on chlorophyll synthesis, but the amount of ALA is reduced, whereas sucrose promotes its accumulation. The results are discussed with completely antitethaal results obtained with tissue cultures of tobacco and are integrated into a scheme which excludes the contrariety of hypotheses deduced from experi- ments with inhibitors of protein and nucleic acid synthesis. It is suggested that the varying results are caused by the action of light on different stages in differentiation of plastids and cells.

In contrast to the enzymes SCoAS, ALAD and PBGA whose activities were determined in vitro, ALAS was assayed in vivo by means of the accumulation of (5-amino-levulinate (ALA) after blocking the enzyme ALAD by levulinate (LA). Optimum accumulation is observed when the concentration is about 2 · 10-2 м. LA is not converted to ALA in appreciable amounts. This could be proved by feeding the plants with 14C-LA which was prepared from uniformly labeled 14C-fructose.
Zur Chemotaxonomie der Alkenvögel. Die Zusammensetzung der Bürzellipide des Tordalks (Alca torda), der Trottel- und Ringellume (Uria aalge) und der Gryllteiste (Cepphus grylle) / Chemotaxonomy of Alcidae. The Composition of the Uropygial Gland Fat from the Razorbill (Alca torda), Guillemot (Uria aalge) and the Blade Guillemot (Cepphus grylle)
Authors: Jacob Jürgen , Zeman Alfred
Published: August 2018

The uropygial gland fats from the razorbill, guillemot (two varieties) and the black guillemot arc very complex mixtures of ester waxes. Among the wax acids n- octanoic acid dominates followed by homologous series of 2-, 4- and 6-monomethyl-, 2,6-, 2,8-, 2,10-, 4,6-, 4,8-, 4,10-, 4,12-dimethyl- and 2,4,8-, 2,6,10-, 2,6,12-, 4,6,10- and 4,8,12-trimethyl-substituted fatty acids. The alcoholic components consist of n-, 2-, 4-, 6-, 8- and 12-monomethyl- as well as 2,6-, 2,8-, 2,10-, 4,6-, 4,8-, 4,10- and 4,12-dimethyl-branched alkanols.

The black guillemot differs from the other species investigated by the occurence of fatty acids which have the first branch in 2- while the others start with the 4-position. The chemotaxonomy of the 20th order of the natural system is discussed.
Ein Cartesianischer Submikrolitertaucher, in dem gemischt werden kann / Mixing of Solutions in a Cartesian Submicroliter-Diver
Authors: Becker W.
Published: August 2018

A method is described of mixing solutions in a cartesian submicroliter-diver with a gas volume of about 0.2 μl. The solutions are mixed within about 10 sec. Approximately 1-2 min after interruption of the experiments the readings are resumed.
Nachweis verschiedener antigener Determinanten vom interspecies Typ in RNS-Tumorviren (C-Typ) der Säuger / Evidence for the Existence of Different Antigenic Determinants of the Interspecies Type in Mammalian RNA-C -Type Tumor Viruses
Authors: Schäfer Werner , Hunsmann Gerhard , Moennig Volker , Wollmann Robert , Pister Liselotte , Deinhardt Friedrich , Hoekstra John
Published: August 2018

In C-type particles of mammalian origin, two different antigenic determinants of the interspecies type have been revealed by a comparative study of murine-, feline-, suidian-, simian (woolly monkey) (SSV-1)-and RD114-viruses. With respect to the distribution of interspecies determinants, these viruses can be arranged into two distinct groups; one comprises the rodent- and cat-, the other the pig- and monkey-viruses. RD114-virus appears to share a certain non-interspecies antigenic component with cat viruses (strains Rickard and Gardner) but behaves, as far as its interspecies antigenic determinant is concerned, more similar to pig- and woolly monkey-viruses. In showing the serological differences mentioned, IgG antibody could replace whole serum.
Komplexbildung von Dehydrogenasen mit Coenzymanalogen und Coenzymbruchstücken / Complexformation of Dehydrogenases with Coenzyme Analogues and Coenzyme Fragments
Authors: Scherr Dietmar , Jeck Reinhard , Berghäuser Jürgen , Woenckhaus Christoph
Published: August 2018

The spectral properties of binary complexes of NAD-analogues and fragments therefrom with I.DH from pig heart or ADH from liver and yeast have been investigated. The NADH-analogues were modified by replacing adenine through benzimidazole, benzene or dihydronicotinamide. Additionally adenosine diphosphate ribose, dihydronicotinamide and dihydronicotinamide- ribose pyrophosphate-5"-ribose have been studied.

It has been shown by means of difference spectra that complexes between ADH from horse liver and analogues cause spectral changes in the region of aromatic absorption at 280 nm even when adenine is absent in the analogues. Spectral changes in the other enzymes mentioned are probably due to changes of the n-π* absorption of the adenine ring. The spectral changes upon complexing indicate hydrophobic interaction of the adenine with the enzyme protein. Fluorescence spectra vary in the intensity of the energy transfer band as well as in coenzyme emission depending on variation of the coenzym analogue. Changing of complex formation between protein and analogues at different pH-values are investigated. ADH from yeast, especially, shows a pK around 6 which suggests interaction with histidine imidazole.
Some Evidence for Light-induced Transfers of Fatty Acids in Euglena gracilis
Authors: Pohl P.
Published: August 2018

Euglena gracilis was grown in the dark for 12 days. Subsequent incubation with sodium octanoate- l-14C in the dark for 6 hours resulted in a rather specific incorporation of radioactivity into the neutral lipids (primarily wax esters). Upon illumination of these cells in an identical medium without radiocarbon, the radioactivities in the neutral lipids decreased strongly, due to a decrease of the labeled wax acids (mainly 1 4:0) and wax alcohols (mainly C14). The radioactivities in phosphatidyl choline and phosphatidyl ethanolamine increased during the first 24 hours of illumination and thereafter decreased. This was caused by the initial increase and subsequent decrease of the labeled 14:0 and 16:0 acids in phosphatidyl choline and of the 14:0, 16:0 , and 18:1 acids in phosphatidyl ethanolamine. The chloroplast lipids (sulfolipid, phosphatidyl glycerol, monogalactosyl diglyceride, and digalactosyl diglyceride) exhibited a steady increase in radiocarbon content. This was due to an increase of label in the 16:0 fatty acid of the sulfolipid, in the 16:0 and trans3-16:1 fatty acids of the phosphatidyl glycerol, and in the saturated and unsaturated C16 and C18 fatty acids of the monogalactosyl and digalactosyl diglycerides. The labeled fatty acids of the above phospho- and glycolipids had comparably high specific radioactivities. Incorporation of radiocarbon into the last two carbon atoms of their methyl ends, however, was low. The glycerol and sugar moieties of the individual lipids incorporated relatively little radiocarbon. It is concluded that in Euglena gracilis the biosynthesis of long chain fatty acids is associated with specific lipids. Upon illumination, oxidative breakdown of the neutral lipids as well as transfers of fatty acids from the neutral lipids via phosphatidyl choline and phosphatidyl ethanolamine to the chloroplast lipids seem to be induced. The lipids involved appear to function as parts of a “lipid-bridge” for the acyl transfers.
Stickstoff-Ausscheidung durch N2-fixierende Blaualgen, I
Authors: Pohl P. , Drath G.
Published: August 2018

The nitrogen fixing blue-green algae, Anabaena cylindrica and Nostoc muscorum , were grown as 71 cultures in various media, at different temperatures (15 °C and 23 °C ), and under light of different wavelengths. In all cases, the amount of combined nitrogen excreted into the medium readied a value of 700 - 800 μMol N/1 of nutrient medium after 4 -6 weeks of growth. Thereafter, this value did not increase significantly. When several cultures of algae were successively grown in the same medium, or when culturing was carried out for a long time with frequent harvesting, the nitrogen content of the nutrient medium remained at approximately the same level as mentioned. The possible reasons for these observations are discussed.
VI. Calcium- und Kaliumionen als Cofaktoren
Authors: Frank Werner
Published: August 2018

Embryonic rat cells are stopped in G1-phase when they are incubated in serum-free medium. They can be triggered to proceed through their cell cycle by the addition of two proteins which have been isolated from fetal calf serum. The influence of calcium and potassium ions on the stimulation process has been exam ined:

1. Ca2+ and K+ ions simultaneously must be present in the culture medium in concentrations of at least 5x10-4 ᴍ and 1x10-3 ᴍ, resp.

2. The intracellular concentrations of both ions are increased by the serum factors.

3. The intracellular concentrations of K+ strongly are dependent on the extracellular Ca2+-concentrations; they increase threefold between 5x10-5 and 1x10-3 ᴍ of Ca2+. On the other hand, the intracellular calcium concentrations are not significantly influenced by the potassium content of the culture medium.
Deuteriumoxid-induzierte Filamentaggregation im Mikronukleus eines Ciliaten / D2O-Induced Filament Aggregation in the Mioronucleus of a Ciliate
Authors: Hauser Manfred , Beinbrech Gemot
Published: August 2018

Keywords

The large spindle-shaped micronucleus of Paramecium bursaria contains filaments of about 60 Å diameter between numerous highly condensed chromosomes. Following treatment for several hours with 10% heavy water the nucleus becomes streched to several times its original length. The filaments, whose number increases noticibly, then appear as an aggregate, which exhibits a somewhat paracrystalline arrangement. An examination of the filament aggregate by means of a laser diffractometer yielded two diffraction lines corresponding to longitudinal periodicities of 91 - 99 and 160 -195 Å. Since both periodicities are comparable to those reported for microtubular proteins, it is assumed the filaments reported here could be related to microtubular material.
Bifunctional Photobinding of Psoralen to Single Stranded Nucleic Acids
Authors: Marciani S , Terbojevich M. , Dall 'Acqua F , Rodighiero G.
Published: August 2018

As psoralen and other furocoumarin derivatives, intercalated between two base pairs of native DNA, under irradiation at 365 nm form inter-strand cross-linkings as a consequence of bifunctional addition, the writers have investigated the ability of psoralen to give such bifunctional photo­ additions, too, with nucleic acids with disordered or partilly disordered structure (denatured DNA and r-RNA).

On the basis of fluorimetric, light-scattering, viscosimetric measurements and of the renaturation ability of denatured bacterial DNA, certain results have been obtained. In addition to monofunctional photoadditions, psoralen can give bifunctional binding by irradiation at 365 nm both with denatured DNA and with r-RNA. However, when irradiation of denatured DNA in the presence of psoralen was performed in a concentrated solution (0.4%), the formation of bifunctional additions between two different strands was demonstrated by the increase (50%) of molecular weight of denatured DNA. However, when irradiation of denatured DNA was performed in more dilute solutions (0.1%), the bifunctional photoaddition of psoralen took place producing only bi­ functional additions in the same strand, very probably with the formation of loops, as has been shown by the absence of increase of molecular weight of DNA and by the more restricted structure assumed by the macromolecule, revealed by the light-scattering and viscosimetric measurements. The formation of these bifunctional additions was confirmed by the reduced rate of renaturation shown by denatured bacterial DNA after irradiation in the presence of psoralen.

In the case of r-RNA, psoralen, when irradiated can form bifunctional additions only in the same strand.
Biochemische Aspekte des Aminosäuren-Stoffwechsels bei Psoriasis vulgaris / Biochemical Aspects of Amino Acid Metabolism in Psoriasis vulgaris
Authors: Peter G. , Angst H. , Koch U.
Published: August 2018

Free and protein-bound amino acids in serum and scales were investigated. In serum the bound amino acids of psoriatics are significantly higher with exception of Pro, Met, Tyr and Phe in contrast to normal subjects. For free amino acids the differences between normal subjects and psoriatics found in serum and scales are not significant. Results are discussed in relation to the single amino acids and the biochemical correlations are outlined which takes the pathological process as a basis.
Effect of the Protons Arising in Aqueous Hydrolysing ATP Solutions, IR Investigations
Authors: Hofmann Klaus P. , Zundel Georg
Published: August 2018

IR spectra of 0.3 ᴍ aqueous solutions of Mg0.5K3-nHMn ATP were plotted. The dependence of the spectra on the hydrolysis was investigated for three different K/H ratios of the nonhydrolysed system. Changes to bands provide information as to the protons added to the phosphate groups and base residues as a function of the initial protonation and degree of hydrolysis. More and more proton addition to the -PO3
-- groups is observed as the initial protonation increases and as the degree of hydrolysis rises. The same applies as far as the addition of protons to the base residues is concerned to the systems with a higher initial protonation. At low degrees of hydrolysis the PO4
3- ions which occur do not bind the two hydrolysis protons completely. 150% protonated PO4
3- ions first form which cross-like via OH+···O hydrogen bonds, which only become more strongly protonated in the systems with a higher initial protonation at large degrees of hydrolysis. The OH+···O bonds between the 150% protonated hydrogen phosphate ions as well as the NH+···N hydrogen bonds between the base residues cause an IR continuum and are thus easily polarizable. An extremely large change to the hydrate structure within narrow hydrolysis ranges is indicated by changes to the bands of the water molecules. The biological relevance of these findings is briefly discussed in the conclusions.
Specificity of Phospholipid Binding to Indole Acetic Acid and Other Auxins
Authors: Veen H.
Published: August 2018

Studies in vitro on the binding of phospholipids with IAA, α-NAA and some of their biologically inactive analogues demonstrate that the observed interaction between IA A and lecithin is not related to the primary action of the hormone in plant growth.
Iridoide und Ecdysone aus Verbenaceae, VI1 . Stilbericosid, ein neues C8-Iridoid aus Stilbe ericoides L. / Iridoids and Ecdysones from Verbenaceae, VI1 . Stilbericoside, a New C8-Iridoid from Stilbe ericoides L.
Authors: Rimpler Horst , Pistor Helga
Published: August 2018

Stilbericoside, a new iridoid isolated from Stilbe ericoides, is shown to have structure 1. The relative configuration is deduced mainly from NMR spectra and double resonance experiments. Because of the great similarity of their NMR spectra 1 and unedoside, a known iridoid, which also occurs in Stilbe ericoides, very probably have the same relative configuration. Unedoside therefore should be represented by formula 2 rather than by the hitherto accepted formula 3 .
1.2.4-Trihydroxybenzol, ein charakteristischer Inhaltsstoff von Gomphidius (Boletales) / 1,2,4-Trihydroxybenzene, a Characteristic Constituent of Gomphidius (Boletales)
Authors: Ardenne Renata von , Steglich Wolfgang
Published: August 2018

1.2.4-Trihydroxybenzene is a characteristic chromogen of Gomphidius (Boletales), responsible for the colour changes to red and dark brown when the sporophores are hurt.
Über Primärreaktionen beim Sehvorgang. Thermodynamischer und kinetischer Einfluß des pH-Wertes auf die Metarhodopsin-I-II-Umwandlung Protonenverbrauch als Auswirkung einer Konform ationsänderung / Primary Reactions in the Visual Process Thermodynamic and Kinetic Influence of pH on the Metarhodopsin I-II Transition Proton Consumption as an Effect of a Conformation Change
Authors: Emrich Hinderk M. , Reich Roland
Published: August 2018

In isolated bovine rod outer segments metarhodopsin I -II absorption-changes are measured using rapid flash-photometry. The rapid H+-uptake accompanying this transition is measured using phthaleine pH-indicators.

1. The meta I -II equilibrium is pH-dependent in the same manner as the proton uptake (Figs 1 ,1 4). This can be explained by the assumption that the meta II conformation is stabilized by the protonization of an amino-group, which in its protonized state cannot be re-enfolded into the hydrophobic core of the molecule, since it is too polar (Fig. 15). In the proposed model the con­ formation-regulating proton binding group is not in the chromophoric region of rhodopsin. This resolves the well known contradiction between the expected bathochromic and observed hypso-chromic shift of meta II H+.

The model furthermore involves that the dissociation-constant of the protonized group differs from the measured apparent pK = 6.3.

2. The meta I -II transition is H+ (and OH-)-catalysed (Figs 4, 5). The kinetics show usually a characteristic deviation from a first-order process (Fig. 2). This can be explained by some in­ homogeneity of the rhodopsin-molecules e. g. some differences in the shieldings of the catalytic centers from H+ (and OH-).

3. The activation energy decreases with increasing proton-concentration (Fig. 6). The protons seem to open a new reaction pathway with a smaller activation energy.

4. Triton X 100 and ethanol increase, sodium-desoxycholate slows down the velocity of the M-I-II-transition, whereas digitonin has only a small effect (Fig. 7).

5. The relaxation-velocity of the optical pH-signal depends on the structural state of the rhodopsin-containing substrate (Figs 10. 11). The outer membrane of the outer segment and the disc-membrane are regarded as possible H+-diffusion-barriers (Fig. 12), because the time lag between MII-signal and pH-signal is nearly eliminated, when the membranes are destroyed by digitonin.

6. In some experiments, using successive non-saturating flashes, an initial H+-uptake of 2 - 3 H+/MII was observed (Fig. 17). After full-bleaching, however, the ΣH+/ΣMII-ratio is one. The hypothesis of a conformative coupling of 2 - 3 rhodopsin-molecules is presented (Fig. 18). The possible existence of an "unfolded" state of rhodopsin is discussed on the basis of a photo-regeneration-experiment, in which no H+-release was observed (Figs 19, 20)
Interferon Effect on Cellular Functions: Enhancement of Virus Induced Inhibition of Host Cell Protein Synthesis in Interferon-Treated Cells
Authors: Suh M , Bodo G , Wolf W , Viehhauser G , Jungwirth C
Published: August 2018

Total protein synthesis in mouse cells but not in confluent chick embryo fibroblasts (CEF) is inhibited shortly after infection with vaccinia virus. This inhibition by the infecting virus is enhanced drastically if the mouse cells have been pretreated with homologous interferon pre­parations. The enhanced reduction of protein synthesis also occurs if the cells are treated with actinomycin D and is therefore to a large extent caused by an enhanced inhibition of amino acid incorporation into host cell proteins. Enhanced inhibition of total protein synthesis during the early stages of infection may be a prerequisite for the complete degeneration of the cells (lysis) which occurs later. Various alterations of mouse cells and chick embryo fibroblasts due to exposure to homologous interferon preparations are discussed with respect to the antiviral state induced in these cells
Methylation of purines and nicotinamide in the rat by dichlorvos
Authors: Löfroth Göran , Wennerberg Rune
Published: August 2018

Rats exposed to [14C-methyl]-dichlorvos excrete labelled 7-methylguanine, 3-methyladenine, and 1-methylnicotinamide in the urine
Direct Demonstration of Dielectric Breakdown in the Membranes of Valonia utricularis
Authors: Coster Hans G. L. , Zimmermann Ulrich
Published: August 2018

It is shown that if the membrane potential of cells of Valonia utricularis was increased rapidly by applying ~500 μs current pulses, dielectric breakdown of the membrane occured when the potential reached a value of ~0.85 V.

The breakdown phenomenon observed was not associated with global damage to the cell or its membrane. The process could be repeated after a short resealing time (~ 10s), many times on a single cell.

The rapidity of the breakdown process (~1 μs) rules out the possibility that dielectric breakdown occurs by a mechanism similar to that of punch-through, which involves changes in ionic profiles.
Interaction between Dehydrogenases and a New NAD⊕-Isomer
Authors: Jeck Reinhard , Woenckhaus Christoph , Holý Antonin
Published: August 2018

A new NAD⊕-isomer was prepared, in which the ᴅ-ribose of the adenosine moiety was sub­ stituted by the enantiomeric ʟ-ribose. As compared to nicotinamide-adenine-dinucleotide (NAD⊕) and NADH the coenzyme isomer (ᴅ,ʟ)-NAD⊕ and its dihydroform (ᴅ,ʟ)-NADH are far less tightly bound to lactate dehydrogenase and alcohol dehydrogenase from horse liver. In the presence of the second substrate (ᴅ,ʟ)-NAD⊕ and (ᴅ,ʟ)-NADH act as hydrogen acceptor and hydrogen donator, respectively, with lactate dehydrogenase and alcohol dehydrogenases from horse liver and yeast. Compared to NAD⊕ and NADH the Michaelis constants are always increased, the catalytic constants (V/Et) were found to be decreased except for the dihydroform reacting with alcohol dehydrogenase from liver.
Synthese einer Partialsequenz aus dem aktiven Zentrum der Streptokokken-Proteinase (EC.3.4.22.10), VI / Synthesis of a Fragment of the Active Center of the Streptococcal Proteinase (EC 3.4.22.10), VI
Authors: Raschig Andreas , Schneider Friedhelm
Published: August 2018

Streptococcal Proteinase, Active Center Peptide, Peptide Synthesis The synthesis and properties of the protected peptide Boc-His(Boc)-Cys(X)-Val-OH(ONP) [X = ferf-butylmercapto, p-methoxybenzyl, tetrahydropyranyl-(2) ] are described. This peptide is a fragment of an active center sequence of the streptococcal proteinase (EC 3.4.22.-10) containing the essential SH group of the enzyme.
Lysolecithin Induced Membrane Alterations in Thymocytes
Authors: Weltzien Hans Ulrich
Published: August 2018

The effects of lysolecithin and of 2 synthetic ether-desoxy lysolecithin analogs, containing alkyl residues of 16 or 12 carbon atoms, on the agglutination kinetics of calf and rabbit thymocytes by concanavalin A (Con A) were investigated. Unlike the natural lysolecithin, these synthetic analogs are resistant to metabolism by membrane associated enzymes. It was found that pretreatment of thymocytes with lysolecithin or with the C16-analog leads to slightly increased agglutination rates. The C12-analog, in contrast, significantly inhibits thymocyte agglutination by Con A. More­ over, a comparison of these results with lysophosphatide effects on the agglutinability of erythrocytes of various species revealed that the inhibitory effect of the short-chain phosphatide is rather specific for thymocytes. The finding that long-and short-chain lysophosphatides, which have previously been shown to react as adjuvants or immunosuppressants, respectively, induce adserve alterations in thymocyte membranes indicates that these substances may affect the immune response by changing the membrane properties of immune competent cells. Concerning the nature of these membrane alterations it was shown that lysolecithin did not affect the number of Con A receptors per cell nor the affinity of lectin binding. It is therefore concluded that the lysophosphatide in­ duced alterations of Con A agglutinability can not be caused by an uncovering or covering of lectin-receptors.
Der elektronenmikroskopische Nachweis der fibrillären Natur des Silberliniensystems bei peritrichen Ciliaten / Electronmicroscopical Demonstration of the Fibrillar Nature of the Silverline System in Peritrich Ciliates
Authors: Foissner Wilhelm
Published: August 2018

A comparative light and electronmicroscopical study about the structure of the cortex, and the location and nature of the silverlines of Telotrochidium elongatum was performed. There is a fibril in the epiplasm below each pellicular ridge. Ultrathin sections of silver stained specimens demonstrate that silver is deposited at and in these fibrills, not only in animals stained with the wet silver method but also in animals stained with the dry one. These findings confirm Klein’s and our own view about the fibrillar nature of the silverline system. The significance of our findings for the elucidation of the structure and function of the cortex is discussed.