bluuebunny/crossref_metadata_2025_split huggingface dataset:
Binary Oscillation of Delayed Luminescence: Evidence of the Participation of QB
- in the Charge Recombination
Authors: Hideg Éva , Demeter Sándor 
Published: August 2018

Abstract
The flash-induced oscillation of a slowly decaying component of delayed luminescence (half time ~ 42 s) was investigated in spinach chloroplasts for various redox states of the secondary acceptor pool (QB). In preilluminated chloroplasts (30 s light followed by 5 min dark) the slow component exhibited a period-4 oscillation as a function of flash number. Upon oxidation of a major part of the QB pool by dark-adaptation or by ferricyanide treatment of chloroplasts, the period-4 oscillation was converted into a period-2 oscillation, providing direct experimental evi­ dence of the participation of QB
- in the charge recombination reaction. The measured oscillatory patterns could be simulated in model calculations by assuming that the slow component originates from charge recombination of the redox couples S2QB
- and S3QB
-.
Chemical Composition of the Wing Gland and Abdominal Hair Pencil Secretions of the Male African Sugarcane Borer, Eldana saccharina (Lepidoptera: Pyralidae)
Authors: Burger B. V. , Mackenroth W. M. , Smith Denice , Spies H. S. C. , Atkinson P. R. 
Published: August 2018

Abstract
In addition to the previously identified wing gland lactone, eldanolide, and the tail brush components, vanillin and p-hydroxybenzaldehyde, several further terpenoid compounds, saturated and unsaturated alcohols and acids, a thioalcohol, as well as two saturated macrocyclic lactones, were identified in the wing gland and tail brush secretions of the male African sugarcane borer Eldana saccharina (Walker).
MTD Approach to Quantitative Structure-Activity Relationships for Cardiotonic Steroids
Authors: Bohl Martin , Simon Zeno 
Published: August 2018

Abstract
A minimal topological difference (MTD) approach is made to describe quantitative structure-activity relationships (OSAR) for the Na+, K+-ATPase inhibitory activity of cardiotonic steroids. The calculations take into account 20 derivatives of digitoxigenin, digoxigenin, and gitoxigenin with small substituents at different sites of the steroid backbone. A multiple correlation coefficient of r = 0.916 is obtained using the MTD and an indicator variable for the presence of a 15β substituent. The corresponding receptor map reveals receptor wall vertices in the C11 , C12, C15, and C22 regions. Both 3β and 16β substituents are found to contain receptor cavity vertices. The MTD results are discussed with respect to lactone-ring conformational investigations presented and they are compared with findings of previous structure-activity studies.
Reaction of Fluorescein Isothiocyanate with Thiol and Amino Groups of Sarcoplasmic ATPase
Authors: Swoboda Gertrude , Hasselbach Wilhelm 
Published: August 2018

Abstract
Several model compounds containing thiol and/or amino groups (mercaptoethanol, glutathione, cysteine, ethanolamine, glycine) were studied with respect to their reactivity towards fluorescein isothiocyanate (followed spectrophotometrically at 504 and 412 nm), stability of product and long­ wave absorption maximum of the fluorescein residue attached. Thiol groups reacted by far more readily than amino groups. A specific effect was observed with cysteine, indicating an intramolecular transfer of the fluorescein residue from SH to NH2.
With sarcoplasmic vesicles both types of reactions were observed. The ratio of products, which can be distinguished by their different stabilities and absorption spectra, depended on the absence or presence of detergents. While with native vesicles the NH2 reaction predominated, with vesicles solubilized with sodium dodecylsulfate, octaethyleneglycol mono-n-dodecyl ether or 1-0-tetradecyl-propanediol-(1,3)-3-phosphorylcholine the SH reaction became prevailing. Already 0.35 mg sodium dodecylsulfate per mg protein were sufficient to give rise to dithiourethane formation exclusively. Excess fluorescein isothiocyanate reacted with several thiol groups of dodecylsulfate-solubilized vesicles. In the presence of ATP binding of fluorescein isothiocyanate to native vesicles was significantly reduced.
Total blockage of the vesicular SH groups with N-ethyl-maleimide led to preparations that reacted with fluorescein isothiocyanate much more slowly, compared to native vesicles. Octaethy­ leneglycol mono-n-dodecyl ether or 1-0-tetradecyl-propanediol-(1,3)-3-phosphorylcholine in the assay accelerated the thioureide formation from N-ethylmaleimide modified vesicles, whereas sodium dodecylsulfate prevented it almost completely.
Our results support the suggestion that one or several thiol groups in vicinity of the highly reactive lysyl residue might play a role in the fast specific reaction, which is only observed with intact native vesicles.
Linear Dichroism Spectroscopy of Retinal with Picosecond Time Resolution
Authors: Lippitsch M. E. , Riegler M. , Aussenegg F. R. , Friedman N. , Sheves M. , Mazur Y. , Margulies L. 
Published: August 2018

Abstract
For the first time linear dichroism spectroscopy has been extended to the picosecond time regime. 11-cis retinal, all-trans retinal and 1,8-diphenyl-1,3,5,7-octatetraene (DPOT) are incorporated into polyethylene films and oriented by stretching the films. By measuring picosecond transient absorption spectra polarized parallel and perpendicular to the stretching direction and calculating the dichroic ratio we get informations about the molecular geometry in excited singlet and triplet states. The results may have relevance to vision.
On the Specificity of the Herbicide Chlorsulfuron in Intact Spinach Chloroplasts
Authors: Homeyer Uwe , Schulze-Siebert D. , Schultz G. 
Published: August 2018

Abstract
In vitro incubation of intact spinach chloroplasts with 1 mᴍ Pyruvate was used to study the specificity of action of the herbicide Chlorsulfuron on the synthesis of valine, alanine and fatty acids. As a result, increasing concentrations of the herbicide strongly inhibited valine synthesis while fatty acid synthesis via pyruvate dehydrogenase complex (PDC) and alanine formation by transamination reaction was promoted.
High Yields of DNA-Transfer into Mouse L-Cells by Electropermeabilization
Authors: Stopper H. , Zimmermann U. , Wecker E. 
Published: August 2018

Abstract
DNA transfection in mouse L-cells was performed by means of the electropermeabilization technique (U. Zimmermann, G. Pilwat, and F. Riemann, Z. Naturforsch. 29, 304 (1974)). The plasmid pSV 2-neo used leads to neomycin-resistance in stably transfected L-cells. Optimized conditions resulted in high yields of clones at relatively low DNA concentration. The influence of temperature during pulse application and during the subsequent resealing process as well as the field parameters and medium com­position are discussed.
Female Urinary Chemosignals Influence Scent-Marking Behavior in Male Mongolian Gerbils (Meriones unguiculatus)
Authors: Probst Bodo 
Published: August 2018

Abstract
The influence of females on the amount of scent-marking behavior displayed by male Mongolian gerbils was investigated. Males isolated from females scent mark at a low level which increases more than two-fold if females are present in the room for three weeks without direct contact with the males. A similar increase is obtained by application of pooled female urine directly onto the males’ noses.
Sex Pheromone Components in the New Zealand Greenheaded Leafroller. Planotortrix excessana (Lepidoptera: Tortricidae)
Authors: Galbreath R. A. , Benn M. H. , Young H. , Holt V. A. 
Published: August 2018

Abstract
Planotortrix excessana was found to include moths of two distinct pheromone-types which were not mutually attractive. Tetradecyl acetate and (Z)-8-tetradecenyl acetate were identified as pheromone components in one, and two other tetradecenyl acetates, probably (Z)-5-and (Z)-7-tetradecenyl acetate, in the other. By contrast with other pheromones reported from the tribe Archipini,⊿11-tetradecenyl compounds were not found in either pheromone-type.
Calcium/Sodium Binding Competition in the Gating of Light-Activated Membrane Conductance Studied by Voltage Clamp Technique in Limulus Ventral Nerve Photoreceptor
Authors: Stieve H. , Pflaum M. , Klomfaß J. , Gaube H. 
Published: August 2018

The membrane current vs. voltage dependence was measured in Limulus ventral nerve photo­receptors at various external Ca2+ and Na+ concentrations, using the voltage clamp technique. Lowering the external concentration of the divalent cations Ca2+ and Mg+ to < 1 μmol/l by adding EDTA causes
1)the light-induced transient conductance increase to disappear and
2)the reversal potential of the membrane current in the dark to shift to a positive value between + 10 and + 20 mV. This value is about the same as the (VrevJD), reversal potential of the total light current under normal ionic conditions. If the external Na+ is lowered to 50 mmol/1 (i.e. 10% of the normal concentration) simultaneously with the lowering of the divalent cation concentration described above, the light response is not abolished and VrevJD is shifted less. The extent of this antagonism depends on the sodium sub­stitute; it is stronger if choline is used instead of lithium.
Lowering of sodium alone to 50 mmol/1, in a saline containing normal Ca2+ and Mg2+ concen­trations, does not change the membrane dark current vs. voltage curve and so VrevJD is not altered; Vrev⊿JL, the reversal potential of the light-induced current, however, is reduced by 10 mV (from +20 to +10 mV). This reduction in Vrev⊿JL can be accounted for by the reduction of the sodium gradient across the cell membrane.
Raising the external Ca2+ concentration to 40 or 100 mmol/l has no conspicuous effect on the membrane current vs. voltage dependence and the gating of the light-induced conductance in­crease.
The results are consistent with our working hypothesis that the gating of the light-activated ion channels in Limulus photoreceptor is controlled by negative binding sites for which calcium- and sodium ions compete with antagonistic actions.
Isolation of the Phytoalexin Medicarpin from Leaflets of Arachis hypogaea and Related Species of the Tribe Aeschynomeneae
Authors: Strange R. N. , Ingham J. L. , Cole D. L. , Cavill M. E. , Edwards C. , Cooksey C. J. , Garrattd P. J. 
Published: August 2018

Abstract
A phytoalexin produced by the leaflets of seven cultivars of Arachis hypogaea (groundnut) after natural infection by Cercospora arachidicola or Phoma arachidicola has been characterised as the isoflavonoid (+)-medicarpin (3-hydroxy-9-methoxypterocarpan). Treatment of excised ground­nut leaflets with an aqueous solution of CuSO4 or with a spore suspension of the fungus Helmin-thosporium carbonum has also been found to stimulate medicarpin biosynthesis.
Proton Uptake by Light Induced Interaction between Rhodopsin and G-Protein
Authors: Schleicher Andreas , Hofmann Klaus Peter 
Published: August 2018

Abstract
The light-induced proton uptake of rod outer segment disc membranes has been investigated in the absence and presence of G-protein. Proton uptake was measured as the alkalisation of the suspending medium using a pH electrode and/or the indicator dye bromocresol purple. It was found that besides the known proton uptake of photolysed rhodopsin additional uptake of one proton accompanies formation of the complex between rhodopsin and G-protein. No measurable proton uptake was found under conditions of rapid redissociation of the complex indicating an only transient protonation during its lifetime. Proton uptake was the same in washed membra­nes recombined with G-protein and in ordinarily stacked rod outer segments. The additional proton uptake reported here is not due to enhanced metarhodopsin II.
Natural Inhibitors of Germination and Growth, III New α-Pyrones from Seeds of Rosa canina
Authors: Lohaus Edith , Zenger Claudia , Rüdiger Wolfhart , Cmiel Edmund 
Published: August 2018

Abstract
The new α-pyrone derivative II was isolated in crystalline form from extracts of dormant seeds of Rosa canina. It inhibits germination of seeds of Amaranthus caudatus completely, but reversibly, at conc. > 2.5 × 10-5 м . Its chemical structure was elucidated by mass spectrometry, 1H-and 13C-NMR spectroscopy to be 3-methyl-1-oxa-bicyclo (4,1,0) hept-5-en-2-one-4,6-dicarboxylic acid di­methylester (II). It is derived from 3-methyl-2H-pyran-2-one-4,6-dicarboxylic acid by cyclo-propanation with diazomethane. The parent compound which is a natural product of the seeds of Rosa canina was isolated as its dimethyl ester I the structure of which was elucidated by mass and NMR spectroscopy. I shows less inhibition of seed germination than II. The reference a-pyrones dimethyl-6-methyl-2H-pyran-2-one-3,5-dicarboxylate (III) , 3-methoxycarbonyl-5-methoxycar-bonylmethyl-6-methyl-2H-pyran-2-one (IV), and isodehydracetic acid methylester (V) did not show any inhibitory activity. The relationship of II with threo-dihydrohematinic acid (VII) is discussed.
Detection of Semiquinone Radicals of N-Acylcatecholamines in Aqueous Solution
Authors: Peter Martin G. , Stegmann Hartmut B. , Dao-Ba Hoang , Scheffler Klaus 
Published: August 2018

Abstract
ESR-spectra were recorded during the oxidation of N-acetyldopamine and N-β-alanyldopamine in aqueous solutions. Semiquinone radicals were detected under conditions of spin stabilization by Zn2+ ions. The appearance of the spectra was the same in the presence or in the absence of proteins. No evidence was obtained for the formation of products that could have arisen eventually from intermolecular Michael-type addition of nitrogen nucleophiles.
Three-Dimensional Models of the Carbohydrate Moieties of Murein and Pseudomurein
Authors: Formanek Helmut 
Published: August 2018

Abstract
Similar density values of q = 1.39- 1.46 g/cm3 and similar repeating periodicities were deter­ mined for murein and pseudomurein. Periodicities of 4.5 and 9.5 Å were measured in the planes of the sacculi of both cell wall polymers. Vertical to these planes periodicities of 42 to 45 A were obtained.
These data may be interpreted as functions of an oblique-angled elementary cell with an area of about 4.5 Å × 10 Å and a height of 21 to 22.5 Å. This elementary cell includes one disac-charidepeptide subunit. As a consequence of this lattice periodicities the glycan strands of murein and pseudomurein perform twofold screw axes. Therefore the peptide chains, linked at distances of about 10 Å to every second sugar residue, point in identical directions. The parallel array of the polysaccharide chains associated with periodicities of 4.5 Å causes, therefore, a separation of the carbohydrate and peptide moieties of murein and pseudomurein. The head-to-head or tail-to-tail packing of such layers provides periodicities of 42-45 Å.
Because of the twofold screw axis of the glycan strands, the secondary structure of the polysac­ charide strands of murein resembles the secondary structure of chitin.
Since all glucosidic oxygen atoms occupy equatorial positions, if the β-1,3 linked N-acetyl-D-glucosamine residues are in the 4C1, conformation and the β-1,3 linked N-acetyl-L-talosaminuronic acid residues in the 1C4 conformation, the polysaccharide chains of pseudomurein may also perform a twofold screw axis.
Fast Atom Bombardment Mass Spectrometry of Coumaric Acids
Authors: Koster Chris G. de , Niemann Gerard J. , Heerma Wigger 
Published: August 2018

Abstract
The technique of positive fast atom bombardment mass spectrometry combined with collisional activation and metastable ion data has been shown to provide molecular mass and useful fragmentation information for discrimination between the coumaric acid isomers. In addition to the occurrence of an ortho-effect, also para and meta positions could be distinguished.
Isoflavonoids from Bolusanthus speciosus (Bolus) Harms Leguminosae
Authors: Asres Kaleab , Mascagni Paolo , O’Neill Melanie J. , Phillipson David 
Published: August 2018

Abstract
Seven isoflavonoids have been isolated from the seeds of Bolusanthus speciosus (Bolus) Harms. Five of these com pounds were identified as the isoflavones genistein (1), biochanin A (2), orobol (3), pratensein (4) and 3′-O-methylorobol (5). The remaining two compounds were characterised as the novel isoflavone 3′-O-methylpratensein (6) and the new 3-hydroxyisoflavanone bolusanthin (7). Identification and characterisation was by means of spectroscopic techniques (UV, IR, MS and 1H NMR). NOe irradiation of the C-2 proton of 3′-O-methylpratensein (6) was used to establish unequivocally the oxygenation pattern of the B-ring.
Volatile Secretions in Three Species of Dufourea (Hymenoptera: Halictidae) Bees: Chemical Composition and Phylogeny
Authors: Tengö J. , Groth I. , Bergström G. , Schröder W. , Krohn S. , Francke W. 
Published: August 2018

Abstract
Volatile secretions from Dufour’s glands in three species of Dufourea bees, Dufourea (Halictoides) dentriventris (Nylander). D.(H.) inermis (Nylander) and D. (Dufourea) minuta Lepelletier have been studied by gas chromatography and mass spectrometry. It was found that the secretions are composed of complex blends of straight chain saturated and unsaturated 2- and 3-ketones and scries of hexanoic and octanoic esters. Cephalic secretions from males and females of D.(H.) inermis and D.(D.) minuta contain sex- and species-specific blends of methylcarbinols and corresponding long chain carboxylic esters. Mass spectrometric fragmentation patterns of esters are described.
Mode of Action of the Hypertrehalosaemic Peptides from the American Cockroach
Authors: Gäde Gerd 
Published: August 2018

Abstract
Although crude extracts of cockroach (Periplaneta amencana) corpora cardiaca have been shown previously to affect the activity of adenylate cyclase and phosphorylase, we demonstrate in the present study for the first time that low concentrations (0.5 to 5 pmol) of the synthetic myoactive peptides. M I and M II, also affect these systems; these myoactive peptides are identical to the hypertrehalosaemic hormones I and II, and cause an increase in the concentration of the second messenger cyclic AMP in the fat body.In addition, both octapeptides activate fat body glycogen phosphorylase and promote breakdown of fat body glycogen. Both peptides increase the levels to haemolymph carbohydrate in a dose-dependent manner.
On the Correlation between Oxygen Uptake in Plastids of Greening Etiolated Oat Leaves and Pigment Photooxidation
Authors: Franck Fabrice , Schmid Georg H . 
Published: August 2018

Abstract
Changes in oxygen evolution or uptake in illuminated plastids were studied during the early stages of greening in etiolated leaves. An oxygen uptake was observed in etioplasts, which persisted even after the appearance of oxygen evolution. This oxygen uptake was most pronounced in etioplasts or in plastids prepared after redarkening the plants. Incubation of pre-illuminated etioplasts in the presence of NADPH resulted in an inhibition of the uptake in a subsequent illumination. Addition of NADPH had three further consequences: a shift of the chlorophyllide absorbance band to 682 nm, an inhibition of pigment photodestruction and the appearance of a light-induced fluorescence transient at room temperature. Inhibition of pigment photodestruction by NADPH was maximal when the experimental conditions favoured the formation of the P682 chlorophyllide-protein.
It is inferred that the oxygen uptake seen under these conditions is due to pigment photooxidation. Inhibition of both phenomena by NADPH is ascribed to the specific interaction of the nucleotide with the pigment-protein complexes and to the ability of these complexes to undergo the light-induced chlorophyllide microcycle, described by Franck and Inoue (Photobiochem. Photobiophys. 8, 85-96, 1984). In the leaf, NADPH is thought to play the same role.
A Fungal Elicitor of the Resistance Response in Wheat
Authors: Kogel Karl-Heinz , Heck Birgit , Kogel Gerd , Moerschbacher Bruno , Reisener Hans-Joachim 
Published: August 2018

Abstract
An elicitor of the lignification response in wheat leaves was isolated from the germ-tube walls of wheat stem rust. The active compound causes metabolic changes typically correlated with the resistance response, i.e. the formation of lignin or lignin-like polymers in affected epidermal and mesophyll cells and the increased activities of enzymes involved in the phenylpropanoid-pathway.
Optimization of Conditions for Accurate Phosphonate and Total Phosphorus Assay on Lipid Samples, in Conjunction with Thin-Layer Chromatography
Authors: Kapoulas Vassilios M. , Tsangaris George Th. 
Published: August 2018

The range of inorganic acid normalities for maximum color formation of the phosphomolybdenum- blue complex (under heating) increases by elevating the ammonium molybdate concentration, and at a ratio of molybdate molarity/acid normality equal to 10, there is maximum color development at any acid normality in the range 1-4 ɴ with either HClO4 or H2SO4 (or their mixtures).
On the basis of these features a revised method is described for the accurate determination of phosphonate-P percent of total-P. on lipid extracts and on TLC bands. The color at the final step, in both cases, is developed under the same conditions of molybdate, HClO4 and H2SO4 concentrations, thus avoiding possible errors produced by the use of two separate calibration curves.
Major Indole Alkaloids Produced in Cell Suspension Cultures of Rhazya strict a Decaisne
Authors: Pawelka Karl-Heinz , Stöckigt Joachim 
Published: August 2018

Eleven main alkaloids were identified from cell suspension cultures of Rhazya stricta grown in 4X-medium for 15 days. The alkaloids comprised the five groups Corynanthe, Strychnos, Eburnan, Secodine, and Aspidosperma and can be regarded as being typical Rhazya alkaloids, although the Strychnos alkaloid akuammicine has been isolated for the first time from the genus Rhazya. The most abundant compound was ( + )-1,2-dehydroaspidospermidine (15 mg/l medium) whereas all other constituents were synthesized in about 5 - 10 times lower amounts. More than 15 further alkaloids were formed as minor components which have not yet been identified. Cultivated Rhazya cells have been shown to be one of the richest alkaloid sources from apocynaceous cell suspensions.
The isolated compounds, because of their structural heterogeneity, cannot be presently arranged into a scheme with coherent biosynthetic sequences.
Identification of (R)-Vicianin in Davallia trichomanoides Blume
Authors: Lizotte Pauline A. , Poulton Jonathan E. 
Published: August 2018

Abstract
The cyanogenic glycoside of young fronds and fiddleheads of the fern Davallia trichomanoides Blume was identified as (R)-vicianin (the β-vicianoside of (R)-mandelonitrile) by acid and enzymic hydrolysis, 1H-NMR and 13C-NMR spectroscopy, and by comparison with an authentic sample isolated from Vicia angustifolia seeds.
Biosynthesis of the Furanoacetylene Phytoalexin Wyerone in Vicia faba
Authors: Al-Douri Nidhal A. , Dewick Paul M. 
Published: August 2018

Abstract
Feeding experiments using 13C-labelled sodium acetate precursors in CuCl2-treated broad bean (Vicia faba) cotyledons have demonstrated that the furanoacetylene phytoalexin wyerone is biosynthetically derived from seven intact acetate units. A further experiment using sodium [2H3]acetate indicated the head of the chain, and showed the chain is analogous to that of a fatty acid precursor, any chain shortening process from postulated C18 precursors occurring from the carboxyl end. Incorporations of oleate and linoleate were, however, regarded as insufficient to prove the involvement of these compounds in the biosynthetic pathway.