bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discrimination of Two Fusogenic Properties of Aqueous Polyethylene Glycol Solutions
Authors: Krähling Hermann 
Published: August 2018

Abstract
Investigations on the dose response of cell fusion, induced by ionfree aqueous polyethylene glycol (PEG) solutions, reveal distinct lowest fusogenic PEG concentrations for different permanently growing mammalian cell lines. Part of the requisite PEG can be replaced by carbo­ hydrates, preserving the fusogenity of the solutions. This discriminates two effects of PEG solutions causing cell fusion: a) cell shrinkage, the required hyperosmolality of the solutions may be provided by PEG or by carbohydrates, is supposed to cause intracellular processes necessary for consolidating polycaryons; b) membrane alterations, which can not be induced by carbo­ hydrates, enable intimate cell-cell contact via particle-free membrane areas. Depending on cell line salts can not only raise the osmolality of PEG solutions but are able to co-operate with PEG in generating membrane alterations.
Effect of Isobutylmethylxanthine and Related Drugs on the Receptor Response (ERG; a-Wave) of the Frog Retina at Various Extracellular Calcium Concentrations
Authors: Leser Karl H. 
Published: August 2018

Abstract
Various drugs known or expected to increase the levels of cyclic nucleotides in cells were applied to isolated superfused frog retinae, and their influence on the aspartate-isolated a-wave was studied. Isobutylmethylxanthine (IBMX), triacetylguanosine (TAG), and dimethylaminopurine (DAMP) strongly influenced the responses elicited from dark-adapted retinae by flashes of light With all three drugs the response amplitude was increased, and latency and time to peak were prolonged. If, on the other hand, the retinae were light-adapted by background light of various intensities, the drugs showed different effects on the response amplitude: IBMX either did not influence the amplitude at all or even caused a decrease (4 of 6 experiments), DAMP decreased the amplitude and TAG caused an increase of the amplitude in 2 of 3 experiments. But latency and time to peak were still prolonged by all three drugs. When dark-adapted retinae were superfused with IBMX or TAG Ringer solution and simul­ taneously calcium concentration was raised, different effects of calcium on the three measured parameters of the a-wave were observed: By increasing the extracellular calcium concentration the increase of the amplitude caused by the drugs was reversed, down or even below the control level, whereas latency and time to peak remained prolonged. Thus, both an increased calcium level and light adaptation had the same effect, namely to reverse only that part of the drug effect concerning the amplitude but not latency or time to peak of the response. The data suggest that calcium and cyclic nucleotides act through different ways in the rod cells.
Unusual Flavanones from a Rare American Fern
Authors: Wollenweber Eckhard 
Published: August 2018

Abstract
Notholaena fendleri, Polypodiaceae, Farinose Exudate, Novel Flavanone Notholaena fendleri is a rare representative of the genus, growing mainly in Colorado/USA. The white farinose exudate on the lower surface of its pinnules is composed partly of waxy material and partly of flavonoid aglycones. The flavonoid moiety consists mainly of methyl derivatives of the flavanones naringenin and eriodictyol. The eriodictyol methyl ethers are rare compounds; eriodictyol-7 methyl ether is a novel natural flavanone. Three flavones and two flavonols are found as trace constituents only. — The farina flavonoids of N. fendleri form a very typical pattern that is characteristic for this species.
Subcellular Compartmentation of Indole-3-acetic Acid in Mesophyll Cells of Spinacia oleracea
Authors: Heilmann B. , Hartung W. , Gimmler H. 
Published: August 2018

Abstract
A compartmental analysis of the distribution of the plant hormone indole-3-acetic acid (IAA) was performed with mesophyll cells of spinach leaves. The results indicated that up to about 45% of the total amount of free IAA in the laminae of spinach is localized within the chloroplasts, although these organelles occupy only about 7% of the tissue volume. This distribution is due to the dissociation properties of IAA which has a pK a of 4,7. The chloroplast envelope is easily permeable for the undissociated acid (IAAH) and less permeable for the anion (IAA"). The rate of uptake of LAA by chloroplasts was linearly dependent on the IAAH concentration gradient between medium and stroma. Uptake was increased by lowering the extraplastidic pH or by alkalization of the stroma during illumination. In illuminated chloroplasts, IAA was accumulated up to 4 fold compared to the surrounding medium owing to the pH gradient between the medium (pH 7.6) and the stroma (pH 8.0). The unexpectedly high plastidic IAA concentration observed in the dark (concentration ratio stroma/medium was about 2) suggested binding of IAA to chloroplast components. Due to this binding, the IAA distribution between medium and chloroplasts must not be used for calculating the stroma pH, as is possible with ABA. However, from the different distribution of IAA in light and darkness the light-induced alkalization of the chloroplast stroma can be calculated.
Drosophila Males Produce a Pheromone which Inhibits Courtship
Authors: Tompkins Laurie , Hall Jeffrey C. 
Published: August 2018

Abstract
Normal Drosophila males produce a volatile pheromone which inhibits courtship. This chemical cue is not identical to the pheromone made by mated female flies, which also inhibits male sexual behavior. Mutant olfC males, which fail to respond to several organic compounds, are not inhibited by the pheromone made by males; hence, unlike normal sexually mature males, olfC males court each other vigorously.
Isolierung und Morphologische Charakterisierung des Kartoffelblattrollvirus (PLRV) / Isolation and Morphological Characterization o f the Potato Leafroll Virus (PLRV)
Authors: Blessing J. , Sarkar S. 
Published: August 2018

Abstract
In spite of its very low concentration, the potato leafroll virus (PLRV) can be enriched from leaf-homogenates of the infected host plant Physalis floridana by a series of separation steps and purified by ultracentrifugation through layers of cesium chloride of defined density. U nder the present experimental conditions the virus accumulates as an invisible band in a region where the density of CsCl is 1.39 ± 0.01 g/cm 3. In negatively stained preparations, the virions show a diam eter of 23 nm and some morphological criteria indicate an icosahedral symmetry.
9(11)-Fernene and Its 21-Epimer as an Epicuticular Layer on Ferns
Authors: Wollenweber Eckhard , Malterud Karl Egil , Gómez P. Luis D. 
Published: August 2018

Abstract
The glaucous epicuticular layer on the undersurface of the leaves of Polypodium glaucinum and the white exudate material on the lower surface of the sterile pinnae of Plagiogyra formosana is shown, mainly by spectroscopical methods, to consist of a mixture of 9(ll)-femene and 21-epi-9(l l)-femene, in both instances in a ratio of ca. 4:1. The 13C-NMR spectrum of 9(ll)-femene has been re­ corded and partially assigned.
Zur Phytochemie südamerikanischer Nephroma-Arten / The Phytochemistry of South American Nephroma-Species
Authors: Renner Bernd , Henssen Aino , Gerstner Ernst 
Published: August 2018

New results on the phytochemistry of Nephroma, a genus of the lichen family Peltigeraceae are presented. Further eight species occuring in South America have been studied. Including earlier results, nine groupings of secondary metabolites within the genus are defined: The phytochemistry of pattern I is represented by N. analogicum containing ergochromes (ergochrome AB and AA), hitherto found only in members of the Parmeliaceae; pattern II: tenuiorin, methylgyrophorate, gyrophoric acid, 4-O-methyl gyrophoric acid, methylevernate, lecanoric acid, zeorin and usnic acid (represented by N. gyelnikii and N. pseudoparile); pattern III: Zeorin, 15α-acetoxy-22- hydroxyhopane and 15α-22-dihydroxyhopane (represented by N. parile and N. expallidum); pat­tern IV: stictic, constictic, hypostictic, hyposalazinic and usnic acid, zeorin and one unknown depsidone [PQ 4] (represented by N. antarcticum and N. lobuligerum); pattern V: no lichen metabolites (represented by N. resupinatum and N. plumbeum); pattern VI: perlatolic, stenosporic and glomelliferic acid, zeorin and five further metabolites being most likely O-methyl-derivatives of stenosporic and perlatolic acid (represented by N. cellulosum and N. lepidophyllum); pattern VII: usnic acid and phenarctin, including three further unknown depsides (represented by N. microphyllum and N. kuehnemanii); pattern VIII: usnic acid, phenarctin, nephroarctin and zeorin (represented by N. arcticum); pattern IX: usnic acid and 6oc-7β-22-trihydroxyhopane (represented by N. chubutense). A considerable variation in accessory compounds exists in pattern II, IV and VI which does not correlate with the variation in morphological characters.
N. patagonicum Kremp. is placed to synonymy with N. analogicum Nyl.
Spectrophotometric Isolation of Kinetically Different Pools of P-700 and Their Correlation to the Reduction of NADP by Isolated Chloroplasts *. I. The Effect of Light Quality and Intensity
Authors: Rurainski Hans J. , Gerhardt Richard , Mader Gerhard 
Published: August 2018

Excitation of isolated chloroplasts in the presence of ferredoxin and NADP by repeated short flashes yields a polyphasic absorption change at 700 nm. Assuming first-order reactions, the signal may be resolved into three distinct components with average relaxation times of approxi­mately 20 μs, 150 μs and 20 ms. Their relative magnitude is dependent on experimental conditions; their spectral characteristics indicate that all three components may be ascribed to P-700.
Concurrent measurements of Y-NADPH, the flash yield of NADP reduction with an enzymatic recycling method, allowed Y-NADPH to be compared to the magnitude of each of the three P-700 components and to total P-700. In general, the data show a good correlation of NADP reduction with the sum of the μs-phases but not with the ms-phase or total P-700.
Analysis of light intensity curves (blue or far red flashes) with a mathematical model which yields maximum values for all parameters at infinite light intensity shows that in both cases approximately two moles of the microsecond component of P-700 turn over for each mole of NADPH formed. In contrast, the molar ratio of the ms-component to the yield of NADP reduction is approx. 0.2 in blue and approx. 6.3 in far red light. The data suggest that only that portion of the P-700 pool which relaxes in the microsecond range may be involved in the reduction of NADP while the ms-component is funtionally isolated from linear electron transport.
Indole Alkaloids from Cell Suspension Cultures of Stemmadenia tomentosa and Voacanga africana
Authors: Stöckigt Joachim , Pawelka Karl-Heinz , Rother Ana , Deus Brigitte 
Published: August 2018

Abstract
Cell suspension cultures of Stemmadenia tomentosa synthesized under normal growth condition the eight major indole alkaloids: (-)-tabersonine, (-)-minovincinine, (+)-conoflorine (voaphyl-line), condylocarpine, (+)-tubotaiwine (dihydrocondylocarpine), (-)-norfluorocurarine (vin-canine), (-)-vinervine, and (-)-coronaridine. These alkaloids consist of the three different types, Aspidosperma, Strychnos and Iboga. In contrast, cultures o f Voacanga africana produced mainly one alkaloid group (Aspidosperma-type) represented by (-)-tabersonine, lochnericine and (-)-minovincinine. Therefore this cell culture seems to be qualified for investigation concerning the biosynthesis of Aspidosperma alkaloids.
A Steroid-Binding Protein from Insect Haemolymph Isolated by PhotoafTinity Labelling and Immunoadsorption
Authors: Reum Lutz , Käuser Gerd , Enderle Ulrike , Koolman Jan 
Published: August 2018

Abstract
Endogenous ecdysteroids as well as radiolabelled exogenous ecdysone were crosslinked to a protein when haemolymph from blowfly larvae was irradiated with UV-light under optimized conditions. This indicates that larval haemolymph of blowflies contains an ecdysteroid-binding protein.
The crosslinked ecdysteroid-protein complex was shown to form a ternary complex when mixed with ecdysteroid-specific antibodies. Formation of the ternary complex was due to a specific interaction of the binding sites of the antibodies with the steroid. This specific interaction was used to isolate the ecdysteroid-protein complex from irradiated crude larval haemolymph by immunoadsorption. The method described here represents a rapid approach for the isolation of steroid-binding proteins by a combination of photoaffinity labelling and immunoadsorption.
Biliverdin IX α, Intermediate and End Product of Tetrapyrolle Biosynthesis
Authors: Köst Hans-Peter , Benedikt Eva 
Published: August 2018

Abstract
Dark-grown cells of the unicellular rhodophyte Cyanidium caldarium were incubated with 17 mmol/l 5-aminolevulinic acid in the dark. The excreted pigments were extracted with chloroform and butanol. The presence of biliverdin IX α in the chloroform-extract (besides phycocyanobilin and other pigments) was demonstrated using TLC, HPLC and chromic acid degradation. A pathway leading to phycocyanobilin is discussed. A green pigment from egg shells of Turdus merula (black bird) was also identified as biliverdin IX α with small amounts of protoporphyrin IX, using the same methods as above.
The Oxidative Degradation of ʟ-Ascorbic Acid via an α-Ketoaldehyde
Authors: Kang Sa-Ouk , Sapper Helmut , Lohmann Wolfgang 
Published: August 2018

Abstract
Dehydro-ʟ-ascorbic acid, the oxidation product of L-ascorbic acid, is unstable in aqueous solution and decomposed by a hydrolytic disruption of its ring structure to 2,3-diketo-ʟ-gulonic acid. It is shown by means of UV, 1H-, and 13C-NMR spectroscopy that after decarboxylation 3,4,5-trihydroxy-2-keto-ʟ-valeraldehyde, an α-ketoaldehyde, is formed. This substance is oxidized further to ʟ-erythroascorbic acid, coupled with a reduction of 2,3-diketo-ʟ-gulonic acid to L-ascorbic acid.
Separation, Partial Purification and Characterization of a Fatty Acid Hydroperoxide Cleaving Enzyme from Apple and Tomato Fruits
Authors: Schreier P. , Lorenz G. 
Published: August 2018

Abstract
A membrane-bound enzyme catalysing the cleavage of 13-hydroperoxy-(Z)-9,(E)-11-oc-tadecadienoic acid (13-LHPO) and 13-hydroperoxy-(Z)-9,(E)-11,(Z)-15-octadecadienoic acid (13-LnHPO) to C6-aldehydes was isolated and partially purified from apples and tomatoes. Attempts to employ Ultrogel AcA 34 and AcA 22 in a gel chromatographic purification step were partially frustrated by reaggregation phenomena. However, by using Sepharose CL-4 B an enzyme fraction (MW 200 000 Da) with lipoxygenase and fatty acid hydroperoxide cleaving activity could be separated from a high molecular-weight active eluate. By applying preparative isoelec­ tric focussing to the tomato protein we succeeded in separating the fatty acid cleaving activity from the lipoxygenase, because o f their different isoelectric points of pH 5.8 -6 .1 and pH 5.0, respectively, An 8.4-fold purification of the fatty acid cleaving activity was achieved. A pH-optimum of 5.5 and a Km-value of 2.6 × 10-5 м/1 for the 13-hydroperoxide of linoleic acid were measured. p-Chloromercuribenzoic acid (1 mм) showed significant inhibitory effect on the fatty acid hydroperoxide cleaving enzyme, but no evidence o f inhibition was found with 1 mм H2O2, KCN, DABCO and EDTA or superoxide dismutase (270 U). The maximum amount of fatty acid hydroperoxide decomposition (C6-aldehyde formation) was determined to be 59%.
Peptidoglycan and Protein, the Major Cell Wall Constituents of the Obligate Halophilic Bacterium Rhodospirillum salexigens
Authors: Tadros Monier Habib , Drews Gerhart , Evers Dierk 
Published: August 2018

Abstract
The obligate halophilic member of Rhodospirillaceae, Rhodospirillum salexigens, does not contain lipopolysaccharide in its thin and delicate gram-negative type cell wall. Major constituents are protein (approximately 70% of dry weight) and peptidoglycan (murein).
Growth Characteristics of in vitro Cultured Ehrlich Ascites Tumor Cells under Anaerobic Conditions and after Reaeration
Authors: Merz Reiner , Schneider Friedh 
Published: August 2018

Abstract
The effects of deprivation of oxygen on proliferation kinetics of in vitro grown Ehrlich ascites tumor cells were studied by means of flow cytometry. The flow cytometric results obtained by applying the BUdR-H 33 258 technique showed that 6 -8 hours after establishment of anaerobiosis cells lose their capacity for proliferation and accumulate in the late G1-phase; during this time late S cells enter the G2 compartment but do not divide while cells, which are in G2+M at the beginning of anaerobiosis divide and enter G1. Cell cycle distribution remained constant up to about 20 hours, thereafter G1-cells enter the S-phase. Up to 24 hours of anaerobiosis cell number does not change and viability of the cells was not severely affected. Recultivation under aerobic conditions of 12 hours anaerobically treated cells revealed, that the cytokinetic properties of G1 cells were not impaired, while S-phase cells after reaeration did not enter G2 but began again to synthesize DNA forming cells with a DNA content greater than 4c. S-phase cells are most sensitive to deprivation of oxygen.
Nachweis von Actinioerythrin in der Roten Seebarbe (Mullus bar bat us L.) (Pisces; Teleostei; Mullidae) / Actinioerythrin in Mullus barbatus L. (Pisces; Teleostei; Mullidae)
Authors: Czygan Franz-C. , Krüger Almuth 
Published: August 2018

Abstract
Actinioerythrin has been isolated together with asta-xanthin-esters and β-carotene from different samples of Mullus barbatus for the first time.
Possible Orientation of the Fatty Acid Chains in Lipopolysaccharide
Authors: Formanek Helmut 
Published: August 2018

Abstract
The fatty acid chains of the lipid A component of lipopolysaccharides are hexagonally packed with a lattice periodicity of 4.1 Å. The smallest subunit of this lattice consists of a disaccharide to which seven fatty acid chains are linked representing the hydrophobic part. Carbohydrates and substituted phosphate residues linked to them form the hydrophilic part of the molecule.
Because of sterical reasons and because of the necessity of a separation of hydrophobic and hydrophilic part, we could derive that the angles of the hydrocarbon chains with the planes of the two sugar residues should be as vertical as possible and the planes of both sugar residues should be approximately coplanar forming an angle of about 180° with one another.
Conformation angles for all the theoretically possible linkages of the disaccaride and of the linkages of the fatty acid residues have been calculated. Between the two-N-acylglucosamine residues theoretically β-1,4, α -1,6 or β-1,6 linkages are possible. The experimentally found β-1,6 linkage has the largest degrees of freedom for its conformation angles.
Anomalous Reduction of Cytochrome b in Highly Purified Complex III from Baker’s Yeast
Authors: Rosa Francisco F. de la , Palmer Graham 
Published: August 2018

Abstract
In highly purified bc1-complex from baker’s yeast, the reduction of cyt c1 and partial reduction of cyt b is obtained by catalytic amount of succinate dehydrogenase and succinate in the presence of 7 μᴍ antimycin. After the addition of ferricyanide the c1 is re-oxidized and a increase in the reduction of b is observed. Using stopped-flow we established that the oxidation of c1 by ferricyanide proceeds as a pseudo-first order reaction and the reduction of b is faster and with two phases. Our observation suggests that these two processes are not directly interconected and that other component than c1 must be the “control factor” in the anomalous reduction of cyt b. This component must be, by exclusion, the iron-sulfur protein.
Studies of Photosynthesis Inhibition by Phytoluminography
Authors: Blaich R. , Bachmann O. , Baumberger Iris 
Published: August 2018

Abstract
Inhibition of photosynthesis by simazine or diuron, as well as disturbance brought about by darkness, fungal infections, heat, high concentrations or lack of CO 2, lead to a luminescence of chloroplasts after irradiation with photosynthetically active light. This effect is the basis of phytoluminography, a new method which may replace in many cases the tedious procedures used at present to determine the photosynthetic capacity of living plant tissue. Both qualitative analyses of luminescence images produced by an image intensifier as well as quantitative measurements using a photomultiplier are possible.
Autoradiographic studies have shown that luminescence images of herbicide-damaged leaves are identical with autoradiographs of the same leaf obtained after labelling with radioactive CO 2. In contrast to autoradiography, phytoluminography does not damage the tested parts of plants nor is there danger of contamination. There is no need for expensive chemicals and skilled technicans, and immediate results are obtained.
Quantitative measurements of phytoluminescence after the application of simazine and diuron (DCMU) to Elodea canadensis in submersed culture showed that approximately 1 ᴍ of inhibitor per 20 ᴍ of chlorophyll (a + b) is needed to obtain maximal luminescence, which indicated total inhibition of photosynthesis.
Both luminescence and inhibition are reversible if the inhibitor is removed by dialysis.
Protochlorophyllide Photoconversion Initiates the Transformation of Reaggregated Prolamellar Body Tubules in vitro
Authors: Müller M. , Nisius A. 
Published: August 2018

Abstract
Completely dissolved components of native prolamellar body/primary thylakoids PLB/PT were induced to reaggregate into tubular structures in vitro. Incubation of these pchlide containing PLB-like tubules under red light with NADPH : pchlide oxidoreductase led to a specific association of the enzyme protein to the tubules. Photoconversion of the pigment initiates the dispersal of reaggregated PLB-tubules as indicated by changes in the content of their main constituent saponin.
The Sarcoplasmic Reticulum of Smooth Muscle Fibers
Authors: Raeymaekers L. 
Published: August 2018

Abstract
The ability of the sarcoplasmic (endoplasmic) reticulum (SR, ER) of smooth muscle cells to accumulate Ca was demonstrated by measuring the uptake of 45Ca in fibers which were chemically skinned with saponin, and by electron cytochemistry of the accumulated Ca. The Ca uptake was dependent on ATP and it was stimulated by oxalate, as it is the case in SR of striated muscle. Electron microscopy of the skinned smooth muscle preparations revealed the presence of calcium oxalate deposits in the reticulum.
The SR vesicles were isolated from several smooth muscles. The purification was carried out by taking advantage of the density increase of the SR vesicles after loading with calcium in the presence of oxalate. Among the muscles investigated the smooth muscle of the pig stomach was found to be the most suitable and it was selected for further biochemical and morphological characterization of the SR vesicles. These vesicles, which contain calcium oxalate crystals, were able to accumulate an additional amount of Ca. The Ca uptake was supported by several energy yielding substrates. Their order of potency was ATP > dATP ≃ UTP > ITP > GTP ≃ CTP. The rate of Ca uptake was two orders of magnitude slower than that in SR of skeletal muscle. The measurement of the level of phosphorylated Ca transport intermediate showed that this difference is due to smaller number of calcium transport sites per vesicle. The distribution of intramembrane particles in freeze-fractured specimens is in agreement with this conclusion.