bluuebunny/crossref_metadata_2025_split huggingface dataset:
Röntgenkleinwinkelstudien über die Substruktur von Helix pomatia Hämocyanin / Small-Angle X-Ray-Scattering Studies on the Substructure of Helix pomatia Hemocyanin
Authors: Pilz Ingrid , Glatter Otto , Kratky Otto 
Published: February 2015

Hemocyanin of the snail helix pomatia was studied by small-angle X-ray scattering in 0.15 M phosphate buffer pH 6.
The outer portion of the scattering curve showed minima, which indicated that the hemocyanin molecule is composed of a large number of identical (or very similar) nearly spherical subunits. From the position of the minima the radius of gyration Ru of the subunit was calculated to be 1.55 nm; this corresponds a diameter of 4 nm assuming a spherical shape. The number of the subunits is discussed, too; a number of 330 can be given as lower limit, a number of 528 as upper limit (most propable value 350 — 400).
Various models were put up by arranging the subunits (diameter 4 nm) in different ways to hollow cylinders. The theoretical scattering curves of these models were compared with the experimental one and a model equivalent in scattering is suggested for the hemocyanin Helix pomatia.
In this model, which fits very well to the experimental curve, 360 subunits form a hollow cylinder. The model shows also the essential features found by electron microscopy by VAN BRUGGEN. The essential features are an arrangement of the subunits in 6 layers vertical to the cylinder axis and a 5-fold screw axis parallel to it.
Das Bürzeldrüsensekret der Dreizehenmöwe (Rissa tridactyla) / The Uropygial Gland Wax from the Kittiwake (Rissa tridactyla)
Authors: Jacob J. , Zeman A. 
Published: February 2015

The uropygial gland fat from the kittiwake is a complex mixture of ester waxes. As acidic components mainly n-octanoic acid and 2-methyl-substituted fatty acids are found. Besides 2,6-, 2,3 and 2,10-dimethyl-substituted fatty acids could be detected.
Among the alcoholic components n-, 2-methyl-, 2,6-, 2,8-, 2,10- and 2,12-dimethyl-substituted primary alkanols were observed.
Chemotaxonomically the kittiwake should be placed between the puffin and the limicoles.
Synthese und Umsatz von Ribonukleinsäuren in suspendierten Säugetierzellen / Synthesis and Turnover of Ribonucleic Acids in Suspended Mammalian Cells
Authors: Trams Günther , Vollertsen Ingeborg , Koch Gebhard 
Published: February 2015

The influence of ionizing radiation on the turnover of high molecular weight RNA in mammalian cells was studied. Growing cultures of suspended human amnion cells were labeled with 32P and irradiated with different doses of X-rays. RNA was isolated by hot phenol and the high molecular weight RNA fractionated by chromatography on methylated serum albumin celite columns. The salt gradient eluted RNA with sedimentation coefficients of 16 S or greater, which were characterized by analysis of nucleotide composition.
Irradiation with doses from 900—6000 R results in degradation of pre-labeled RNA. A quantitative determination reveals that more 32P-radioactivity leaves the high molecular weight RNA compared to labeled total material that is degraded to acid soluble products. This indicates that RNA is partly broken down to low molecular weight fragments.
Nucleotide analysis of the high molecular weight RNA fractions indicate a preferred degradation of ribosomal precursor RNA.
The experimental results give evidence that the analysis of RNA synthesis for a certain period after irradiation is complicated by interfering processes like the simultaneous degradation of RNA.
The Coordination Chemistry of Phosphoryl Compounds Containing the — N(CH3)2 Group, Part VIII
Authors: De Bolster M. W. G. , Groeneveld W. L. 
Published: February 2015

A number of new solvates and adducts containing bisphenyldimethylaminophosphine oxide is reported. The solvates have the general formula M[(C6H5)2P(O)N(CH3)2]4
2+(anion-)2, in which M = Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn and Cd, and the anions are ClO4
- and BF4
-. The adducts have the general formula M[(C6H5)2P(O)N(CH3)2]2Cl2, where M stands for the same series of metals.
The compounds are characterized and identified by chemical analyses and physical measurements.
Ligand-field and vibrational spectra have been investigated; values for the ligand-field parameters are reported. It is concluded that coordination takes place via the oxygen atom of the ligand.
X-ray powder patterns were used in combination with ligand-field spectra to deduce the coordination around the metal ions.
The interesting behaviour of the nickel (II) chloride adduct upon heating is discussed and it is shown that both a square pyramidal and a tetrahedral modification exists.
Thionicotinamide-NADP, a Nucleotide Analog Interfering with Ferredoxin-NADP Reductase/Ferredoxin Interaction
Authors: Böger Peter 
Published: February 2015

Diaphorase and transhydrogenase activities (system NADPH; dichlorophenolindophenol and NADPH;NAD, respectively) of ferredoxin-NADP reductase are increased by ferredoxin. Reduced thionicotinamide-NADP (TN-NADPH) only slightly inhibits these activities with no ferredoxin present in the assay, but the activity increments in the presence of ferredoxin are strongly decreased. Photosynthetic pyridine nucleotide reduction is also inhibited by the reduced analog, the extent of inhibition being approx. in the same order with all three activities. The ferredoxin stimulated activities therefore appear to be due to the same interaction between reductase and ferredoxin in all three cases.
The inhibition by TN-NADPH resembles that with Na-pyrophosphate (or NaCl), although in contrast to salt inhibition it is a.) not alleviated by higher ferredoxin concentrations, and b.) it still allows reductase/ferredoxin binding.
The binding of the reduced pyridine nucleotide analog to the reductase seems to interfere rather specifically with the stimulation which ferredoxin can exert on the enzymic activities of the reductase.
Die Flavon-C-glykoside von Viola tricolor L. / The Flavone-C-glycosides of Viola tricolor L.
Authors: Wagner H. , Rosprim L. , Düll P. 
Published: February 2015

For a flavone-di-glycoside from a garden variety of Viola tricolor L. the structure 5,7,4′-Trihydroxyflavone-6-C-β-ᴅ-glucopyranosyl-8-C-α-ʟ-rhamnopyranoside was elucidated using mainly perjodate oxidation, NMR- and mass-spectroscopy.
From the same plant besides the mono-C-glucosides Vitexin, Saponaretin, Orientin and Isoorientin four Apigenin-di-C-glycosides were isolated, one of them proved to be identical with Vicenine-2.
Studies on Esterases Levels in Various Tissues of Uromastix Hardwickii during Activity and Hibernation
Authors: Farzana Farida , Hasnain S. N. 
Published: February 2015

Esterases, acetylcholinesterase and cholinesterase activities were determined in various tissues of Uromastix hardwickkii during hibernation and activity.
1. The protein concentration was significantly reduced during hibernation.
2. The esterase activity in all the tissues was found to be significantly reduced during hibernation.
3. Acetylcholinesterase activity was significantly increased in all the tissues.
4. There was no significant difference in the cholinesterase activity duriing the two periods.
5. The specific activities of all the enzymes were found to be significantly increased during hibernation.
Nitroalkanes as Reductive Substrates for Flavoprotein Oxidases
Authors: Porter David J. T. , Voet Judith G. , Bright Harold J. 
Published: February 2015

Nitroalkanes have been found to be general reductive substrates for D-amino acid oxidase, glucose oxidase and L-amino acid oxidase. These enzymes show different specificities for the structure of the nitroalkane substrate.
The stoichiometry of the D-amino acid oxidase reaction is straightforward, consisting of the production of one mole each of aldehyde, nitrite and hydrogen peroxide for each mole of nitroalkane and oxygen consumed. The stoichiometry of the glucose oxidase reaction is more complex in that less than one mole of hydrogen peroxide and nitrite is produced and nitrate and traces of 1-dinitroalkane are formed.
The kinetics of nitroalkane oxidation show that the nitroalkane anion is much more reactive in reducing the flavin than is the neutral substrate. The pH dependence of flavin reduction strongly suggests that proton abstraction is a necessary event in catalysis. A detailed kinetic mechanism is presented for the oxidation of nitroethane by glucose.
It has been possible to trap a form of modified flavin in the reaction of D-amino acid oxidase with nitromethane from which oxidized FAD can be regenerated in aqueous solution in the presence of oxygen.
Eine neue strukturelle Variante des BaAl4-Typs: Der CaBe2Ge2-Typ / A New Structural Variant of the BaAl4-Type: The CaBe2Ge2-Type
Authors: Eisenmann B. , May N. , Müller Wiking , Schäfer Herbert 
Published: February 2015

The ternary intermetallic compounds CaBe2Ge2, BaMg2Pb2 and BaZn2Sn2 have been prepared. Their crystal-structures have been determined. They are isotypic and crystallize in a new variant of the BaAl4-type (Space group: P4/nmm — D4h
7, lattice parameters:
CaBe2Ge2: a = 4,02 ± 0,02 Å
c = 9,92 ± 0,02 Å
BaMg2Pb2: a = 5,00 ± 0,02 Å
c = 12,11 ± 0,02 Å
BaZn2Sn2: a = 4,69 ± 0,02 Å
c = 11,33 ± 0,02 Å).
Osmium(VIII) Catalyzed Oxidation of Acetone and Ethylmethyl Ketone by Chloramine-T
Authors: Mushran S. P. , Sanehi R. , Agraval M. C. 
Published: February 2015

The Osmium (VIII) catalyzed oxidation of acetone and ethylmethyl ketone by chloramine-T, in highly alkaline solutions showed first order dependence to chloramine-T and osmium (VIII). The order of the reactions with respect to alkali and ketone were found to be fractional, being ~-0.82 and 0.3 respectively. No effects of ionic strength were evident. The mechanism has been proposed on the basis of the formation of a complex between N-chlorotoluene-p-sulfonamide and osmium (VIII) in the slow step, which in turn oxidizes the enol anion of the reducing substrate in the fast step.
During the study of the mechanism of oxidations by chloramine-T, the kinetics of the oxidation of α-hydroxy acids 1 in presence of osmium (VIII) as catalyst, glycerol2 in neutral and alkaline media, p-cresol3 in an acidic medium, hexacyanoferrate (II)4 in a feebly acidic medium (pH 6-7) and aliphatic aldehydes 5 in alkaline media have been investigated.
Despite the high redox potential6 of the chloramine-T/toluene sulfonamide system (1.138 V at pH 12), the oxidation of acetone does not take place in absence of catalyst and that of ethylmethyl ketone proceeds only in highly alkaline solutions7 (NaOH>0.01 M). In the present note the kinetics of the osmium (VIII) catalyzed oxidation of acetone and ethylmethyl ketone have been recorded.
Die Wasser- und Ionen-Permeabilität der Zellmembran von Protozoen unter Einwirkung von ultraviolettem Licht / The Permeability of the Protozoan Cell Membrane to Water and Ions under the Action of Ultraviolet Light
Authors: Hildebrand Eilo , Stieve Hennig 
Published: February 2015

The action of ultraviolet light on certain membrane properties of protozoa was investigated in Paramecium, Euplotes, and Opalina using the following methods: observation of morphological changes of the animals, recording of the osmoregulatory organelle (Paramecium), and measurement of membrane potential and resistance by means of intracellularly inserted microelectrodes.
This paper presents only slow effects which occur within some minutes after uv irradiation and does not directly concern excitability of protozoa.
Due to large uv doses swelling was observed both in Paramecium and Opalina; in Euplotes a liquid-filled vacuole was formed.
Small uv doses cause an increase in the frequency of the contractile vacuole of Paramecium; larger doses diminish the frequency reversibly (Fig. 4), and even larger doses lead to an irreversible inactivation of this organelle.
Membrane potential and membrane resistance in Opalina are shown to change in different ways under continuous irradiation (Fig. 13): After a transient decrease the membrane potential increases to about the initial value and after this it decreases to zero, whereas the membrane resistance decreases from the beginning of irradiation.
The spectral sensitivity curve (Fig. 9) obtained from a standard decrease of the membrane potential shows a maximum at about 280 nm and a rise from 250 nm towards shorter wavelengths.
The results indicate an influx of water following the osmotic gradient and an increase of the membrane permeability to cations. With respect to the different behavior of membrane potential and conductivity the mechanism of uv action is discussed. The most probable assumption is that the permeability increases unspecifically but gradually in succession for water, chloride, potassium, and sodium. The possibility of disruption of disulfide links is discussed with respect to the spectral sensitivity curve. It is suggested that the altered permeability is based on photochemically induced changes of the structure of proteins which are either part of the membrane or have an important function in the regulation of the membrane permeability.
Dipole Moments and Molecular Conformation of Allylcarbonylnitrosyl Iron Complexes
Authors: Sorriso S. , Cardaci G. , Murgia S. M. 
Published: February 2015

The dipole moments of the complexes π (CH2CXCH2) Fe (CO) (NO) L, with X and L equal, respectively, to H, CO; H, P (C6H5)3; CH3, CO; Cl, CO; Br, CO, have been measured. From the results it is concluded that:
1. The value of the group moment

is ca. 1.6 D, if

= 1.3 D and Co-Fe-CO(NO) =98°.
2. A trans structure appears most likely in the π (CH2CYCH2) Fe (CO) 2NO (Y = Cl, Br, CH3).
3. Qualitative comparison between

and

group moments confirms that the C5H5 group bonds to manganese as (C5H5)δ-.
Die UV-Dimerisation von 1.3-Dimethyluracil in der Eismatrix / UV-Dimerization of 1,3-Dimethyluracil in Ice-Matrix
Authors: Fahr Egon , Fürst Gerhard , Maul Peter , Wieser Heinz 
Published: February 2015

UV irradiation of 1,3-dimethyluracil in ice-matrix yields four dimeric dimethyluracils (2 c) - (5 c), which could be isolated by preparative thin-layer chromatography. Attemps for structure elucidation of these four dimers by UV, IR, NMR and mass-spectrometric methodes pointed out, that only NMR-spectra give structural evidences; by IR - not by mass-spectra - certain identification of dimers is possible.
In accordance with dimeric thymines and dimeric uracils the syn-dimeric dimethyluracils (3 c) and (5 c) are stable in 6 N HCl, the anti-dimers are monomerisized. Investigations of stability in HCl gives informations about structures of cyclobutane pyrimidine dimers
Ultraviolet Absorption and Optical Rotatory Dispersion Studies of Deoxyribonucleic Acid and Nucleohistone
Authors: Basu S. 
Published: February 2015

This report concerns the ultraviolet absorption and optical rotatory dispersion (ORD) of DNA and of nucleotides down to 185 mμ. An absorption band (y) at about 195 mμ occurs for all these compounds. Similar studies have been made on histones and nucleohistone. These indicate a strong absorption below 200 mμ due to protein. Consequently, if any native DNA is associated with some amount (2 - 12%) of protein (e.g., histones), the molecular absorption of DNA in the said region becomes masked, and no clear y-maximum due to DNA occurs in the absorption spectrum. The absorption of DNA in the y-band region (ca. 190 mμ) seems to be decreased as a result of DNA-protein interaction. No significant change is observed in the absorption region of DNA at longer wavelengths (250-290 mμ). The y-peak of DNA appears at about 190 mμ on complete removal of proteins. This peak is sharper than the conventional one (x) at 260 mμ and is hyperchromic on denaturation, and involves multiple Cotton effects to any degrees similar to that observed at the second peak (260 mμ).
The absorption (also ORD) features of nucleohistone at the x and y wavelengths do not provide similar information (e.g., denaturation artefacts) regarding the structure of the nucleohistone contained DNA which is apparently distinct from the structures of native and partially denatured (denaturation 10%) DNA. The weaker π-π* transition (190 mμ) in the DNA bases is very susceptible to nucleoprotein interaction. This result has been used to explain the influence of nucleoprotein interaction on the configuration of DNA in nucleohistone
Studies on Carbohydrate Metabolism in Lizards
Authors: Ali Athar H. S. , Hasnain S. Nazrul , Zain-Ul-Abedin M. 
Published: February 2015

1. Initial glycogen levels in the liver were found to be significantly higher than in the kidneys of the two species studied. The glycogen levels in kidney were however considerably higher than in some mammalian species.
2. Total reducing capacity, true glucose, saccharoid fraction and titratable acidity increase gradually with concomitant decrease in the glycogen levels when liver and kidney homogenates of uromastix and liver homogenate of varanus were incubated for a period of 4 hours.
3. Total reducing capacity, true glucose and the titratable acidity increase gradually, while the glycogen and the saccharoid fraction remain unchanged when the kidney homogenates of varanus are incubated for 4 hours.
4. Total reducing capacity, true glucose and saccharoid fraction in the blood of uromastix are higher than in varanus. The blood glucose levels in both the species are higher than found in the mammals
Reaktionen fluorierter Alkyldithiophosphonsäuren mit metallorganischen Verbindungen / Reactions of Fluorinated Alkyldithiophosphonic Acids with Metal Organic Compounds
Authors: Roesky Herbert W. , Dietl Michael , Norbury A. H. 
Published: February 2015

The preparation of (CH3)3SnSPSFC2H5, Pb(SPSFCH3)2, Pb(SPSFC2H5)2 and CH3HgSPSFCH3 is described. On the basis of NMR the structure was formulated as

. All the complexes are colourless and monomeric in solution.
The magnetic and reflectance spectra of Cr(S2PFCH3)3, Mn(S2PFC2H5)2, Co(S2PFCH3)2, Ni(S2PFCH3)2 and Ni(S2PFC2H5)2 are reported and interpreted.
Schichteinlagerungsverbindungen des Niob- und Tantaldisulfids mit n-Alkylaminen / Layer Intercalation Compounds of Niobium and Tantalum Disulfide with n-Alkylamines
Authors: Schöllhorn Robert , Sick Erwin , Weiss Armin 
Published: February 2015

NbS2 and TaS2 react with n-alkylamines to form intercalation complexes similar to those observed with TiS2. The arrangement of the guest molecules in the interlayer space is dominated by the interaction host lattice-amine nitrogen, if the alkyl chain of the amine contains 4 to 9 C-atoms. In complexes containing 12 to 18 C-atoms per alkyl chain, the van der Waals interaction between the alkyl chains is essentially responsible for the sterical arrangement of the intercalated molecules.
Investigations with n-octadecylamine-NbS2 and oleylamine-NbS2 in the temperature range of 20-120°C lead to the observation of severval reversible phase transitions. These transitions are caused by conformational changes of the guest molecules as well as by changes in the ratio RNH2: NbS2.
Zur Kenntnis der Chemie der Metallcarbonyle und der Cyanokomplexe <br />in flüssigem Ammoniak. XXX.
Authors: Lindner Ekkehard , Behrens Helmut , Uhlig Dieter 
Published: February 2015

The IR spectrum of Na2[Cr(CO)5], which has been obtained by reaction between Cr(CO)6 and sodium in liquid NH3, is discussed. The oxidation to Na2[Cr2(CO)10] in THF has been followed IR spectroscopically.
The reactions between Na2[Cr(CO)5] and Mo(CO)6, W(CO)6 and Fe2(CO)9 lead to the mixed binuclear carbonylmetallates Na2[(OC)5Cr - Mo(CO)5], Na2[(OC)5Cr -W(CO)5] and Na2[(OC)5Cr - Fe(CO)4].
Synthesis of Pure and Mixed Double Oxides with the Ilmenite Structure
Authors: Gellings P.J. , Van De Velde G. M. H. 
Published: February 2015

A new method for synthesizing double oxides of the ilmenite and perovskite type via aquafluoro-complexes MII(H2O)xAIVF6 has now successfully been applied to dilute solid solutions of iron (II) magnesiumtitanates FexMg1-xTiO3.
Chemical analysis and X-ray powder diffraction analysis of lattice spacing shifts of different compositions warrant the conclusion that random solid solutions of mixed double oxides can be obtained by the chosen method, with the special advantages of stoichiometry and lower reaction temperatures than in previously described methods.
Massenspektrometrische Untersuchungen an Borchelaten der Pyridin- und Chinolin-Reihe und deren N-Oxiden / Mass Spectrometric Investigations on Boron Chelates of the Pyridine and Quinoline Type and their N-Oxides
Authors: Hohaus Eberhard , Riepe Wolfgang 
Published: February 2015

Mass spectra of chelate-6-rings (N-oxide-chelates) are similar to those of comparable chelate-5-rings after elimination of oxygen from the fragment ion (M-C6H5). It is assumed that the fragment ion [(M-C6H5)-O] exists as a five-membered ring.
However, there are two exceptions which are: The diphenyl boron chelate of pyridine-2-carboxylic acid anilide N-oxide with O-B-O-coordination and the difluorine boron chelate of 8-hydroxyquinoline N-oxide. The stable fragment OBX (X = C6H5F) is eliminated directly from the fragment ion (M-X). It is assumed the ring closure in [(M-X)-O] obviously is less favoured. The preparation of both 5-ring-chelates using the components is impossible, too.
Presynaptic NR2A-Containing NMDARs Are Required for LTD between the Amygdala and the Perirhinal Cortex: A Potential Mechanism for the Emotional Modulation of Memory?
Authors: Laing Michael D. , Bashir Zafar I. 
Published: February 2015

AbstractVisual recognition memory relies on long-term depression-like mechanisms within the perirhinal cortex and the activation of the lateral amygdala can enhance visual recognition memory. How the lateral amygdala regulates recognition memory is not known, but synaptic plasticity at amygdala−perirhinal synapses may provide a mechanism for the emotional enhancement of recognition memory. In this study, we investigate the mechanisms of long-term depression (LTD) at the amygdala−perirhinal synapse in male Lister Hooded rats. We demonstrate that LTD at this input relies on NR2A-containing NMDARs, located presynaptically. Therefore, the underlying mechanisms of LTD, at the amygdala−perirhinal input, which may regulate the emotional context for recognition memory, are different to previously described postsynaptic NR2B−NMDAR mechanisms of intraperirhinal LTD that subserve recognition memory.
ThePolgMutator Phenotype Does Not Cause Dopaminergic Neurodegeneration inDJ-1-Deficient Mice
Authors: Hauser David N. , Primiani Christopher T. , Langston Rebekah G. , Kumaran Ravindran , Cookson Mark R. 
Published: February 2015

AbstractMutations in theDJ-1gene cause autosomal recessive parkinsonism in humans. Several mouse models ofDJ-1deficiency have been developed, but they do not have dopaminergic neuron cell death in the substantia nigra pars compacta (SNpc). Mitochondrial DNA (mtDNA) damage occurs frequently in the aged human SNpc but not in the mouse SNpc. We hypothesized that the reasonDJ-1-deficient mice do not have dopaminergic cell death is due to an absence of mtDNA damage. We tested this hypothesis by crossingDJ-1-deficient mice with mice that have similar amounts of mtDNA damage in their SNpc as aged humans (Polgmutator mice). At 1 year of age, we counted the amount of SNpc dopaminergic neurons in the mouse brains using both colorimetric and fluorescent staining followed by unbiased stereology. No evidence of dopaminergic cell death was observed inDJ-1-deficient mice with thePolgmutator mutation. Furthermore, we did not observe any difference in dopaminergic terminal immunostaining in the striatum of these mice. Finally, we did not observe any changes in the amount of GFAP-positive astrocytes in the SNpc of these mice, indicative of a lack of astrogliosis. Altogether, our findings demonstrate theDJ-1-deficient mice,Polgmutator mice, andDJ-1-deficientPolgmutator mice have intact nigrastriatal pathways. Thus, the lack of mtDNA damage in the mouse SNpc does not underlie the absence of dopaminergic cell death inDJ-1-deficient mice.