bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zuckerbausteine, Chemotypen und Serotypen der Leptospiren
Authors: Parnas J. , Poplawski S. , Cybulska M. T. , Książek A. 
Published: February 2015

Wir berichten hier über die Chemotypen serologisch verschiedener pathogener und saprophytärer Leptospiren. Alle Leptospiren, pathogene und saprophytäre (L. biflexa Patoc), wie deren Polysaccharid-Fraktionen sind in der Zusammensetzung der Zuckerbausteine fast identisch. Das gleiche gilt für die Aminosäuren.
Das bedeutet, daß das Genus Leptospira, das 13 Haupt-Serotypen besitz, durch nur einen Chemotyp charakterisiert ist; ebenso ließ sich nur ein Infrarottyp nachweisen.
Nachweis der Ferredoxin-NADP-Reduktase in der Oberfläche des Chloroplasten-Lamellarsystems mit Hilfe spezifischer Antikörper
Authors: Berzborn R. 
Published: February 2015

Antisera against purified ferredoxin-NADP reductase (E.C.1.6.1.1) inhibited photosynthetic NADP-reduction and NADPH2 diaphorase activity of the enzyme. The antisera contained precipitating antibodies against the enzyme. One of the precipitin lines visible after immunoelectrophoretic analysis of the purified reductase was shown to contain diaphorase activity.
The antisera against reductase did not agglutinate isolated lamellar systems of chloroplasts directly. Combination of antibodies to reductase, however, with bound reductase in the surface of lamellar systems could be demonstrated and indirect agglutination was observed, when the lamellar systems were incubated with an antiserum against reductase and when subsequently reductase or an antiserum to rabbit-γ-globulin was added.
These findings indicate, that at least one antigenic determinant of ferredoxin-NADP reductase is accessible to antibodies at the surface of the lamellar system of chloroplasts. Probably this surface is not plane, but possesses protrusions or deepenings of at least half the length of an antibody molecule (ca. 100 A). In these cavities one or more determinants of bound reductase would be located.
Berechnung von Ionisierungsenergien aus Redoxpotentialen
Authors: Stanienda A. 
Published: February 2015

Ionization energies and electron affinities of organic and inorganic substances are obtainable from reversible anodic and cathodic half-wave potentials, solvation energies and the electron work function potential of the electrode metal. Solvation energies were calculated using a modified Born equation in which the molecular radius was corrected for the ionization energy. It is possible to compute the first ionization potential of organic compounds with a deviation from experimental data of less than 3 per cent. The calculated electron-affinities do not agree with values given in the literature but are equal to the difference in energy between the first excited state and ionization potential.
Electron work function potential of platinum measured by an indirect method was found to be 4,43 ev.
Zur Interaktion von Anthracyclinen und Anthracyclinonen mit DNS / Interaction of Anthracyclines and Anthracyclinones with DNA
Authors: Berg H. , Eckardt K. 
Published: February 2015

It was shown by the polarographic data of the complexes between antracycline antibiotics and DNA that in contrast to their biological inactive aglycones and other antracyclinones, a cooperative interaction of the intercalating chromophore as well as the sugar residue of the anthracycline molecules, is generally responsible for the complex formation with DNA.
The high complex binding constants of the antracyclines daunomycin, nogalamycin, galirubin A and galirubin B measured in dimethylsulfoxid-buffer solution are in the same order of magnitude as those of actinomycins. On the other hand, only a weak binding ability of the aglycones daunomycinon, ε-pyrromycinon and aklavinon, as well as of other investigated anthracyclinones and model hydroxyanthraquinones, could be observed.
No significant influence of the number and positions of the chromophore hydroxyls could be noticed.
The results suggest that the first outerphase addition of the sugar residues to the backbone of the helix gives the necessary space of time for the slower intercalation process of the planar chromophore.
In the case of denatured DNA, the antibiotic-DNA-complex has a lowered stability.
The important role of the sugar residue for the binding mechanism strongly suggests that modifications of the nature and position of the basic sugar residue should be most valuable for the synthesis of new effective anthracyclines.
Über das sterische Verhalten einer unterbrochenen Alpha-Helix / On the Steric Behaviour of an Interrupted Alpha-Helix
Authors: Jarosch R. 
Published: February 2015

The revolutions and motions of the side-chains occuring on an interrupted Alpha-Helix after a change in the length of its hydrogen-bonds have been described with the help of an elastic moleculemodel.
Fig. 1 shows the directions of the revolutions (rotating arrows) after shortening of the hydrogenbonds in the case of the same (a, b, c, d) and different coiling-sense (e, f, g) of the two helical segments fixed at definite points (indicated by tongs). After elongation of the hydrogen-bonds all arrows point to the opposite directions. In the case of fig. 1 g and longer helices a drift in the surroundings may appear which is always directed to the cleft between the helices (arrows). The straight arrows indicate the shifting-tendency in the surroundings caused by the wave-propagation of the rotating helix.
The side-chains between adjacent areas of the helices move towards each other in the cleft near the nonhelical region (compare e. g. the side-chains 5 and 16 in figs. 2 a and 2 b). Moreover extreme changes in the position of certain side-chains occur in the interhelical segment of the polypeptide-chain (13 in figs. 2 b and 4 b, 12 in fig. 3 b). The amide-groups of the interhelical segment become unstable if the interhelical segment contains more than 3-4 dissociated hydrogen-bonds. In this case the changes in the positions of its side-chains (e. g. 13, 14, 15 in figs. 5 b and 6 b) are determined and occur strongly only when the interhelical segment is fixed in its middle (e. g. by 15 in fig. 6 a).
The possible importance of the described movements for the conformational changes of globular proteins is discussed.
Die Beziehungen zwischen Lipochinonsynthese und Plastoglobulibildung in den Chloroplasten von Ficus elastica Roxb. / The Correlation between Lipoquinone Accumulation and Plastiglobuli Formation in the Chloroplasts of Ficus elastica Roxb.
Authors: Lichtenthaler H. K. , Weinert H. 
Published: February 2015

The structure of plastids, as well as size and frequency of the osmiophilic plastoglobuli were studied from the development of Ficus leaves until the degeneration of older leaves and compared with the accumulation of excess plastid-quinones.
1. The plastids on the young, light green Ficus leaves still rolled up in the buds already contain thylakoids. Prolamellar bodies and small plastoglobuli are, however, still present. Few days after leaf-unfolding the prolamellar bodies are used up in thylakoid formation; the number of plastoglobuli is reduced concurrently.
2. Thereafter size and frequency of the osmiophilic plastoglobuli increase with the age of Ficus chloroplasts. In several-year-old green Ficus leaves large plastoglobuli up to 3,5 μ diameter with the greatest frequency at 0,5 μ diameter can be found.
During chloroplast degeneration in senescent leaves both thylakoids and plastidstroma are dissolved progressively. The plastoglobuli remain. Their size still increases during chlorophyll breakdown. In the final yellow tob rown stage of Ficus leaves the plastids predominantly contain some larger plastoglobuli up to 7 μ arising by fusion of smaller ones.
3. The accumulation of excess plastidquinones - mainly α-tocopherol and plastohydroquinone 45 - proceeds concurrently to the formation and enlargement of the plastoglobuli. It is shown that the excess plastidquinones of Ficus chloroplasts are deposited in the osmiophilic plastoglobuli whose size thus increases. The isolated plastoglobuli predominantly contain α-tocopherol and plastohydroquinone 45, in lower concentrations also plastoquinone 45, α-tocoquinone, and vitamin K1, traces of carotenoids, but no chlorophylls.
4. During chlorophyll and thylakoid breakdown those lamellar lipids (carotenoids, plastidquinones) not decomposed are deposited together with the newly formed plastidquinones in the osmiophilic plastoglobuli. Plastoglobuli of degenerating chloroplasts thus contain more carotenoids than plastoglobuli from fully functional chloroplasts of green Ficus leaves.
Spaltungsreaktionen an perfluorierten Anhydriden
Authors: Roesky Herbert W. , Giere H. H. 
Published: February 2015

Die Darstellung von

aus CH3N(Si(CH3)3)2 und P2O3F4 wird be-schrieben. Durch Spaltung von F2S2O5 mit CH3N(Si(CH3)3)2 und (CH3)3SiN=C=NSi(CH3)3 entstehen FSO2- NCH3-Si(CH3)3 und FSO2N = C = NSi(CH3)3. CF3SO2OSO2CF3 reagiert mit
(CH3)3SiN = C = NSi(CH3)3, (CH3)3SiOSi(CH3)3 und

zum CF3SO2N= C = NSi(CH3)3,
CF3SO2OSi (CH3)3 und

. CF3SO2NH2 setzt sich mit (CH3)3SiCl in Gegenwart
von (C2H5)3N zum

um. Mit dem Salz NaOCNC (CF3) 2 reagiert CF3SO2OSO2CF3 zum CF3SO2OCNC (CF3) 2. Bei sämtlichen Reaktionen wird die S - O - S- oder P - O - P-Bindung sehr leicht gespalten. Die neuen Verbindungen sind farblose Flüssigkeiten oder Festkörper. Die IR-, 1H- und 19F-KMR-Spektren werden mitgeteilt.
Hemmstoffe der Photosynthese VII
Authors: Röchling H. , Frasca Edith , Büchel K. H. 
Published: February 2015

Die Umsetzung von Benzimidazolonen mit Isocyanaten und mit Carbamoylchloriden führt zu N-Carbamoyl-Derivaten. Die Darstellung und Isolierung von zwei isomeren Tetrachlor-benzimidazolonen wird beschrieben. Ausgehend von Tetrachlorbenzimidazolonen erhält man Pentachlor- und Hexachlor-benzimidazol.
Einige Substitutions- und Quaternisierungs-Reaktionen am Pentachlorbenzimidazol werden durchgeführt.
Über die Koordinations-Isomerie der Kobalt-methyl-Derivate der Cobyrsäure und der Cobinamid-monocarbonsäuren
Authors: Friedrich Wilhelm , Messerschmidt Reinhard 
Published: February 2015

Kobalt-methyl-cobyrsäure sowie Kobalt-methyl-cobinamidmonocarbonsäuren lassen sich partialsynthetisch in zwei diastereoisomeren Formen darstellen. Das Synthesegut enthält ca. 10% Isomer a (hier ist die CH3-Gruppe „unten“ gebunden) und ca. 90% Isomer b (CH3-Gruppe „oben“) im Falle der Cobyrsäure bzw. ca. 22% Isomer a und ca. 78% Isomer b im Falle der Cobinamid-monocarbonsäuren.
Durch Belichtung bei 20°C bzw. Erwärmung auf 80°C, vor allem in CO-Atmosphäre, werden die Kobalt-methyl-cobyrsäuren a und b isomerisiert unter Bildung von Gemischen aus Isomeren a und b. Isomerisierung von Kobalt-methyl-cobyrsäure a führt zu einem Gleichgewicht, welches etwa der Zusammensetzung des Synthesegutes entspricht. Die CH3-Gruppe kann auch auf Aquocobalamin übertragen werden unter Bildung von Kobalt-methyl-cobalamin; auch diese Reaktion wird durch CO beschleunigt.
Die Katalyse der Isomerisierung bzw. Methylübertagung durch CO dürfte darauf beruhen, daß dieses Gas die im Medium stets in kleinen Mengen vorhandenen Diaquo-corrinoide reduziert unter gleichzeitigem Verbrauch von restlichem Sauerstoff. Homolyse bzw. Heterolyse der Kobalt-Kohlenstoff-Bindung durch Licht bzw. Wärme führt ebenfalls zu reduzierten Corrinoiden - neben Methylradikalen bzw. Methylkationen. Reagieren die letzteren mit fremden reduzierten Corrinoidmolekülen bzw. mit der fremden Seite der eigenen Moleküle, dann ergibt sich eine Isomerisierung bzw. Methylübertragung.
Quantitative Messung der Singulett- und Triplett-Absorptions-Spektren von Phäophytin a und b / Pheophytin-a and Pheophytin-b; Quantitative Absorption Spectra of the Singuletand Triplet-State
Authors: Zanker Valentin , Rudolph Ernst , Prell Gerhart 
Published: February 2015

Quantitative singlet absorption spectra dependent on solvent, temperature, and concentration are shown. The bands observed in the visible and UV region are assigned to 3 π → π*-electron transfers.
Measurements at different acidities showed that the pheophytin molecule can be present in 3 prototropic forms; as a base, a mono- or a divalent cation.
In polar solvents of concentrations >10-4 M dimerization occurred. Larger clusters were formed in non-polar solvents at concentrations <10-4 Μ and at temperatures below ca. 200 °K.
The quantitative triplet (T) -absorption spectra for pheophytin a and b are also reported: the longest wavelength T-T-band is expected in the region 5000-8000 cm-1. The relaxation times and quantum yields of triplet formation are given; simple first order kinetics were found to fit the decay curves.
Der Einfluß von partiellen Hepatektomien auf die Hepatomrate nach Diäthylnitrosamin-Gaben
Authors: Grünthal D. , Hellenbroich D. O. , Sänger P. , Maass H. 
Published: February 2015

Rats were hepatectomised and subsequently diethylnitrosamine was applied orally (2 mg DENA/kg/d). Compared with a non-treated control group the mean survival time was lowered from 225 to 158 days. In a second experiment repeated hepatectomies were performed. All these rats were killed after 40 weeks and after a total DENA dose of 351 mg/kg. By histological examination of the livers a higher rate of hepatomas was found in the hepatectomised group.
Thus the proliferating processes during liver regeneration seem to favour the hepatocarcinogenesis under DENA treatment.
Das Bürzeldrüsensekret der Saatkrähe (Corvus frugilegus) / The uropygial gland fat of the rook (Corvus frugilegus)
Authors: Jacob Jürgen , Glaser Armin 
Published: February 2015

The uropygial (preen) gland fat of the rook (Corvus frugilegus) is a mixture of ester waxes of which 2-methyl-substituted fatty acids with a chain length of C16-C22 are shown to be the acidic components.
The alcoholic components are n-alkanols with a chain length of C6-C12.
As to the 32nd order of the natural system the uropygial gland fat seems to differ in the single families already if compared with that of the common sparrow
Interactions of Chlorophyll Monolayers with Electron Donors and Acceptors
Authors: Brody Seymour Steven 
Published: February 2015

Photoreactions and complexation reactions between monolayers of chloroplyll a, at a water-air interface, and various electron donors and acceptor in a Wilhelmy film balance.
When phenazine methosulfate (PMS), ascorbate, benzyl viologen (BV), or dehydroascorbic acid are present in the aqueous subphase, the area/molecule increases with substrate concentration in accordance with a Langmuir- type adsorption isotherm. The increase in area is attributed to a reorientation of chlorophyll upon complex formation. The surface potentials and areas/molecule (at zero pressure) are 350 mV and 179 Å2 for PMS + ascorbate in the subphase, 300 mV and 175 Å2 for PMS, 310 mV and 146 Å2 for BV, 310 mV and 156 Å2 for ascorbate, 230 mV and 146 Å2 for dehydroascorbic acid. The equilibrium constants are 170 × 103 ᴍ-1 for PMS + ascorbate, 64 × 103 ᴍ-1 for PMS, 41 × 103 ᴍ-1 for BV, and 3.9 × 103 ᴍ-1 for ascorbate. Formation of a complex decreases the slope of the isotherm, thereby giving the film a more liquid nature. Chlorophyll does not complex with oxidized PMS.
Illumination of the chlorophyll · BV complex in a nitrogen atmosphere results in an oxidation of chlorophyll; the photoproduct (probably Chl⊕ · BV⊖) has a larger area/molecule, of 165 Å2, and a lower surface potential, of 280 mV. Illumination of the chlorophyll · ascorbate complex or the chlorophyll · PMS · ascorbate complex results in a reduction of chlorophyll. The photoproduct of the former reaction (probably Chl⊖ · -oxidized ascorbate) has a larger area/molecule, of 169 Å2, and a lower surface potential, of 290 mV. The photoproduct of the latter reaction (probably Chl⊖ · PMS · oxidized ascorbate) has a larger area/molecule, of 211 Å2, and a larger surface potential, of 380 mV. No evidence is observed for a photoreaction with the Chl · PMS complex or the Chl · dehydroascorbic acid complex. A value of 0.03 is determined as a lower limit for the quantum yield of these reactions. In all cases the absorption spectrum of the chlorophyll recovered from surface after irradiation shows no significant differences from the control.
Polarographische Untersuchung des Systems Folsäure — Dihydrofolsäure — Tetrahydrofolsäure / Polarographic Examination of the System Folic Acid — Dihydrofolic Acid — Tetrahydrofolic Acid
Authors: Kretzschmar Klaus , Jaenicke Walther 
Published: February 2015

7,8-Dihydrofolic acid and tetrahydrofolic acid were prepared from folic acid. The three compounds were examined by different polarographic methods. The diffusion coefficient of folic acid was determined independently.
Folic acid is reduced via a reversible 2-electron step, an irreversible transformation of the primary product, giving 7,8-dihydrofolic acid. The reduction is continued by two further 2-electron steps with an intermediate chemical reaction (the cleavage of the side chain). The redox potentials are measured and the mechanism of the reaction is discussed.
On the Role of Plastoquinone in Photosynthesis
Authors: Böhme H. , Reimer S. , Trebst A. 
Published: February 2015

Dibromothymoquinone and its hydroquinone are inhibitors of non cyclic electron flow from water to NADP, anthraquinone or methylviologen. The inhibition is competetively reversed by plastoquinone. It appears that dibromothymoquinone is an antagonist of plastoquinone and that it prevents the enzymic (by the next endogenous carrier of the chloroplast electron transport chain) but not the chemical (by ferricyanide) reoxidation of reduced plastoquinone. This follows from the result that the photoreduction of ferricyanide and DCPIP * is not inhibited by dibromothymoquinone in sonicated chloroplasts and is inhibited in intact chloroplasts to only 60% or 80% respectively. It is concluded that dibromothymoquinone does not inhibit photoreductions by photosystem II.
According to their response to dibromothymoquinone, cyclic photophosphorylations can be subdivided in those requiring plastoquinone and those which do not. Menadione catalyzed cyclic photophosphorylation is inhibited by dibromothymoquinone, whereas the PMS catalyzed system is not. The DAD cyclic system is only partly inhibited by dibromothymoquinone. The PMS catalyzed cyclic photophosphorylation in the presence of dibromothymoquinone is antimycin sensitive, which suggests that the PMS system can switch from a plastoquinone dependent system to a plastoquinone independent, but cytochrome b dependent system, which is now antimycin sensitive. Ferredoxin catalyzed cyclic photophosphorylation is inhibited by dibromothymoquinone as well as by antimycin. The data indicate that non cyclic electron flow through both photosystems is obligatory dependent on plastoquinone, whereas cyclic systems do not necessarily include plastoquinone. The relevance of the results to the possibility of different coupling sites in cyclic and non cyclic electron flow systems is discussed.
IR-spektroskopische und kristallstrukturelle Untersuchungen an 2.4-Pentandionato-Lithium-(Li-acac)-Einkristallen / IR-Spectroscopic and X-Ray Structural Investigation of 2,4-Pentandionato-Lithium (Li-acac) Single Crystals
Authors: Funck E. , Jungermann A. , Kaiser J. , Schröder F. A. 
Published: February 2015

Single crystals of Li-acetylacetonate (Li-acac) were characterised by microscopical, IR-reflection and X-ray diffraction measurements.
The space group was found to be C cca (orthorhombic). From the IR-spectra (polarised radiation) and the properties of the space group the probable arrangements of the molecular species in the crystal are deduced.
Nitril als intraanulare Gruppe / Steric Interactions of Inner Atoms in Cyclic Compounds, 18 The Nitrile Group as an Intraanular Substituent
Authors: Vögtle Fritz , Zuber Michael , Neumann Peter 
Published: February 2015

Cyclophane, Konformationsanalyse, Nitril-Gruppe, Protonenresonanz, Sterische Wechselwirkungen
The bridged aromatic compounds 1-3 with internally projecting nitrile groups have been prepared. The cyclophanes 1 and 3 are conformationally rigid due to steric hindrance of the inner cyano groups; 2 shows partial conf ormational mobility.
1.2-Dimethyl-3.4-diisopropyl-cyclobutadien-eisentricarbonyl und Trimethyl-isopropyl-cyclobutadien-eisentricarbonyl / 1,2-Dimethyl-3,4-diisopropyl-cyclobutadiene-irontricarbonyl and Trimethylisopropyl-cyclobutadiene-irontricarbonyl
Authors: Brune Hans Albert , Wolff Hans Peter , Hüther Hans 
Published: February 2015

Thermal cyclization of 2,9-dimethyl-deca-3,7-diyne yields 3,4-bismethylene-1,2-diisopropyl-cyclobut-1-ene. This forms by addition of two molecules of hydrogen chloride at -78° several - with respect to the positions of the four alkyl substituents - isomeric trans-3,4-dichloro-dimethyl-diisopropyl-cyclobut-1-enes. From reaction of this mixture of isomers with diiron-enneacarbonyl 1,2-dimethyl-3,4-diisopropyl-cyclobutadiene-irontricarbonyl is obtained in a 21% yield. Trimethyl-isopropyl-cyclobutadiene-irontricarbonyl has been prepared by an analogous route from 8-methyl-nona- 2,6-diyne.
Chemical properties and spectroscopic data of these complexes are discussed with respect to structure and bonding.
Zellvermehrung und energieabhängige Stoffwechselleistungen von Ehrlich-Ascites-Zellen unter aeroben und anaeroben Bedingungen / Cell Division and Energy Dependent Metabolic Power of Ehrlich-Ascites-Tumor Cells Under Aerobic and Anaerobic Conditions
Authors: Krause H. P. , Probst H. , Schneider Fr. 
Published: February 2015

Interrelations between energy metabolism and cell division were studied with permanent in vitro cultured Ehrlich-ascites-tumor-cells during the second passage in vitro. The following parameters were estimated under aerobic and anaerobic conditions and in the presence of dinitrophenol:
DNA- and RNA-synthesis measured by the incorporation of 14C-thymidine and 14C-uridine; rate of glycolysis measured by lactate production; permeation of 14C-2-aminoisobutyric acid; ATP level of the cells; cell division and number of dead cells.
The following results were obtained: Cell division and thymidine incorporation are obligate oxygen dependent processes. It was not possible to decide, whether respiration alone can maintain cell propagation. Respiration alone and glycolysis alone cannot maintain a normal level of ATP. Only an intact respiration can maintain the penetration of 2-aminoiso-butyric acid. Glycolysis alone and respiration alone can supply the energy for the incorporation of uridine. The incorporation of uridine is also influenced by oxygen dependent reactions not related to energy production. The number of dead cells does not rise significantly under anaerobic conditions.
Molekulargewicht, Größe und Gestalt von Proteinen der Thylakoidmembran / Molecular Weight, Size and Shape of Thylakoid-Membrane Proteins
Authors: Menke Wilhelm , Ruppel Hans-Georg 
Published: February 2015

Chloroplasten, Membranproteine, Molekulargewicht, Konformation
The lamellar system of chloroplasts, dissolved in concentrated formic acid, may be freed from lipids by dialysis or gel filtration. The structural protein on both sides of the isoelectric region is water-soluble. The molecular weight was determined to be 470 000 at pH 3.0 - 3.4. Electron micrographs reveal disc-like particles of variable diameter but constant thickness. Particles of 100 Å diameter and 50 Å thickness are mainly observed. The limiting viscosity number [η] = 12 (ml/g) demonstrated that the particles are also anisodiametric in solution. It follows from changes in circular dichroism and infrared absorption that the conformation of the polypeptides is altered by the formic acid treatment. The structural protein can be separated into polypeptides in buffers containing dodecylsulphate, yielding a major component of molecular weight 25 000. From these experiments it may be concluded that one protein layer is contained in the thylakoid membrane which is composed of supra-molecular structural elements.