bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tropomyosin-Troponin-Induced Changes in the Partitioning of Free Energy Release of Actomyosin-Catalyzed ATP Hydrolysis as Measured by ATP-Phosphate Exchange
Authors: Dancker Peter 
Published: August 2018

Abstract
ATPase activity and ATP-Pi exchange of unregulated (without tropomyosin-troponin) and regulated (with tropomyosin-troponin) acto-HMM were measured in media containing 0.2 mg/ml actin, HMM, and (when present) tropomyosin-troponin, 2 mM MgCl2, 10 m M KCl, 2 mM NaN3, 10 mM Pi(pH 7.0), 3 mM ATP. The following mean values for ATPase activity and for the rate of incorporation of P, into ATP (each per mg HMM and per min) were obtained: unregulated acto-HMM 0.33 nmol Pi and 0.33 nmol Pi, regulated acto-HMM 0.54 nmol Pi and 1.06 nmol P*. The ratio of P4 incorporation rate to ATPase activity was 1.01 × 10-3 for unregulated and 2.02 × 10-3 for regulated acto-HMM. From these ratios and from the overall free energy change of ATP hydrolysis it was calculated that under the prevailing experimental conditions in unregulated acto-HMM 62% and in regulated acto-HMM 66% of the free energy change of ATP hydrolysis occurs after the release of phosphate from actomyosin. It is probably this part of the free energy change that is used by the muscle for the performance of work.
The Effect on Ammonium Chloride on the Kinetics of the Back Reaction of Photosystem II in Chlorella fusca and in Chloroplasts in the Presence of 3-(3,4-Dichlorophenyl)-1 ,1 -dimethylurea
Authors: Vierke Gerhard 
Published: August 2018

Abstract
The effect of NH4Cl on the kinetics of the back reaction of photosystem II as derived from luminescence measurements was investigated in dark adapted Chlorella in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) at different temperatures. The kinetics of the back reaction which, under these conditions, leads to the reduction of the S2 state by the primary electron acceptor Q- of photosystem II was observed to be considerably slowed down in the presence of NH4Cl.
Analysis of the kinetic results in the light of the theory of the back reaction developed by Mar and Roy (J. Theor. Biol. 48, 257-281 (1974)) revealed two opposite effects of NH4Cl to be present simultaneously:
1) The enthalpy of activation of the back reaction was lowered (catalyzing effect of NH4Cl)
2) The frequenca factor which indicates the number of collisions of the reacting molecules in the membrane per second is largely decreased (inhibitory effect of NH4Cl).
This reduction of the mobility of the recombining species of the back reaction is the predominant effect of NH4Cl. It is suggested that this effect is due to a change of the conformational state of the membrane induced by dissolution of relative large amounts of NH? within the lipid phase of the thylakoid membrane. This hypothesis is supported by the observation that the value of the exciton yield of the back reaction changes upon addition of NH4Cl.
Light-Induced Valence Change of a Manganese-Containing Chlorophyll Derivative
Authors: Lazar Günter 
Published: August 2018

Abstract
K3(Mn-(III)-chlorin e6) acetate, a water-soluble chlorophyll derivative with manganese as central atom was prepared. The influence of reducing agents, light, and bicarbonate on the oxida­ tion states of manganese in the chlorin complex was investigated. In alkaline solutions the central Mn3+ was reducible to Mn2+. The illumination of the partially reduced complex first accelerated the reduction (light reduction: Mn3+ → Mn2+), which was then followed by a strong reoxidation (light oxidation: Mn2+ →* Mn3+) continuing after switching off the light. This redox effect of light was obtained only in presence of hydroxylamine as reducing agent. Illumination time, intensity, and frequency had an influence on this effect. In the light/dark change the process was reversible. In regard to the requirement of manganese for the photosynthetic oxygen evolution the observed valence change of manganese in the chlorin complex was compared to the supposed reaction mechanism on the donor side of photosystem II.
Effect of Irradiation and Immobilization on Spinach Chloroplast Activities
Authors: Fujimura T. , Yoshii F. , Kaetsu I. , Inoue Y. , Shibata K. 
Published: August 2018

Abstract
The effect of y-ray irradiation and immobilization by means of radiation polymerization on PS II activity (O2 evolution) of isolated chloroplasts from spinach was investigated. Reduction of O2 evolution activity by irradiation was small at lower temperatures below – 24 °C, but the activity decreased slightly by freezing at extremely low temperature below –78 °C. So the optimum low temperature range for the treatment was observed. The immobilized chloroplast in a hydrophilic polymer matrix showed the stable duration of O2 evolution activity more than 700 h at 4 °C . Thermo-stability of chloroplast was also improved greatly by immobilization. The active center of PS II in immobilized chloroplasts was retained even after 60 min standing at 50 °C.
Construction of Phylogenetic Trees By Pattern Recognition Procedures
Authors: Sharaf Muhammad Abdallah , Kowalski Bruce R. , Weinstein Boris 
Published: August 2018

Abstract
The sequence of a protein can be graphed as a discrete function and a cross-correlation between any two such number sets produces a similarity score. The scores are used to prepare a phylogenetic tree involving hierarchical cluster analysis, non-linear mapping, and minimal spanning routines. Changes are suggested in the sequences of cytochrome c’s from Mediterranean fruit fly, locust, and rattlesnake. The method is faster than existing procedures and does not require human intervention at any stage.
Phenolics from Larix Needles. XV. High-Performance Liquid Chromatography of L. gmelinii Flavonoids
Authors: Niemann Gerard J. 
Published: August 2018

Abstract
From needles of Larix gmelinii sixteen flavonoids were isolated and identified. The main flavonoids had been analyzed before, eight minor ones were identified as quercetin-3-glucoside, isorhamnetin-3-glucoside and -3-ara-binoside, a somewhat lipophilic kaempferol-3-glucoside derivative, apigenin-7-glucoside, laricitrin-3-rutinoside and laricitrin-and syringetin-3-(p-coumarylglucoside).
Kinetics of the Back Reaction of Photosystem II as Derived from Delayed Light Emission in the Presence of DCMU and the Conformational State of the Thylakoid Membrane
Authors: Vierke Gerhard 
Published: August 2018

Abstract
It is shown that the kinetics of the back reaction of photosystem II in the seconds time range as derived from the luminescence decay curve in the presence of DCMU is controlled by the internal pH of the thylakoids. Modifications of the conformational state of the photosynthetic membrane while leaving the internal pH unchanged, however, reaction.
Reversed Phase High Performance Liquid Chromatography of Essential Oils
Authors: Strack Dieter , Proksch Peter , Gülz Paul-Gerhard 
Published: August 2018

Abstract
A reversed phase high performance liquid chromatographic procedure for the separation of essential oils is described. Applying water-acetonitrile elution systems on octyl and octadecylsilane- bonded silica, complex mixtures of sequiterpenes and oxygenated volatile constituents can be resolved, comparably to the quality of gas chromatographic analysis. Photometrical detection at different wavelengths can be an important parameter in optimizing the separation of essential oil constituents. The application of the described method is demonstrated with naturally occurring mixtures of terpenes from leaves of Cistus ladanifer.
Isolation of the Phytochrome Chromophore. The Cleavage Reaction with Hydrogen Bromide
Authors: Rüdiger Wolfhart , Brandlmeier Thomas , Bios Inge , Gossauer Albert , Weller Jens-Peter 
Published: August 2018

Abstract
The cleavage of the bilin chromophore from C-phycocyanin with hydrogen bromide yields 3E-configurated phycocyanobilin (4) as the major and 3 Z-configurated phycocyanobilin (5) as the minor reaction product. The reaction of synthetic 3E-configurated phytochromobilin (2) with hydrogen bromide and methanol leads only to a methanol adduct at the C-18 side chain (7) whereas the same reaction with the 3Z-configurated phytochromobilin (3) leads to 7 and 2. The bilin chromophore was cleaved also from phytochrome after preparation of phytochromobilin peptides. The detection of 2 and 7 suggested that 3Z-and 3E-configurated phytochromobilin were the primary products of cleavage from phytochrome. A reaction scheme is given which can explain the results of the reaction with hydrogen bromide and methanol.
Superoxide-and Ethane-Formation in Subchloroplast Particles: Catalysis by Pyridinium Derivatives
Authors: Elstner E. F. , Fischer H. P. , Osswald W. , Kwiatkowski G. 
Published: August 2018

Abstract
Oxygen reduction by chloroplast lamellae is catalyzed by low potential redox dyes with E′0 values between -0 .3 8 V and -0 .6 V. Compounds of E′0 values of -0 .6 7 V and lower are inactive. In subchloroplast particles with an active photosystem I but devoid of photosynthetic electron transport between the two photosystems, the active redox compounds enhance chlorophyll bleaching, superoxide formation and ethane production independent on exogenous substrates or electron donors. The activities of these compounds decrease with decreasing redox potential, with one exception: 1-methyl-4,4′-bipyridini urn bromide with an E′0 value of lower -1 V (and thus no electron acceptor of photosystem I in chloroplast lamellae with intact electron transport) stimulates light dependent superoxide formation and unsaturated fatty acid peroxidation in sub­ chloroplast particles, maximal rates appearing after almost complete chlorophyll bleaching. Since this activity is not visible with compounds with redox potentials below -0 .6 V lacking the nitrogen atom at the 1-position of the pyridinium substituent, we assume that 1 -methyl-4,4′-bi-pyridinium bromide is “activated” by a yet unknown light reaction.
Changes Induced by Pre-Fixation in Polycation Bacteriolysis and Surface Alterations Matching the Model of Wall Picnosis in Cell Lysis
Authors: Popescu Alexandru , Antohi Stefan , Trasculescu Stefan , Aurescu Adriana , Manolescu Nicolae , Ciocnitu Victor 
Published: August 2018

Abstract
Pretreatments of B. subtilis and S. aureus cells with lower concentrations of fixative agents, led to modifications in bacteriolytic effect exerted by polyarginine and protamine: Glutaraldehyde blocked polycation bacteriolysis while formaldehyde and osmium tetroxide (OSO4) having no influence on polyarginine action, increased constantly the cell sensitivity to protamine in lower doses otherwise nonlytic; the sensitizing action also resulted in the extension of protamine bacteriolytic pattern including several staphylococcal strains; higher bacteriolytic doses of protamine were contrastively unable to lyse OSO4 prefixed cells and gave an inconstant lytic value with formaldehyde treated bacteria. With higher concentrations, OSO4 preserved intactly its sensitizing action while formaldehyde displayed a decrease in its ability to sensitize B. subtilis cells to the lytic effect of protamine. Scaning electron microscopy of polycation treated cells showed prelytic lesions as surface granulations, shape and size modifications and cell splits. The interpretation of the results in terms of intra-and intermolecular adducts accompanied by con­ formational changes in surface macromolecules is discussed. It is concluded that the results match the model of polycation bacteriolysis by wall multizonal picnosis leading to surface splits and thereby triggering cell-lysis.
Toxizität und cytostatische Wirkung von PtCl2(NH3)2 nach i. v. und intratumoraler Injektion / Toxicity and Cytostatic Effect of PtCl2(NH3)2 after i. v. and i. t. Injection
Authors: Wenzel M. , Schneider M. , Bier J. 
Published: August 2018

Abstract
oxizität und cytostatisch e W irkung von PtCl2(NH3)2 nach i. v. und intratumoraler Injektion Toxicity and Cytostatic Effect of PtCl2(NH3)2 after i. v. and i. t. Injection In tumor bearing mice intratumoral injection of PtCl2(NH3)2-solution increases the cytostatic effect while decreasing its toxicity in comparison to i. v. injection. In­ tratumoral injections of water-in-oil emulsions of the platin-compound are less cytostatic but have a consider­ ably lower toxicity.
Hydrogen Evolution Catalyzed by Hydrogenase in Cultures of Cyanobacteria
Authors: Hallenbeck Patrick C. , Kochian Leon V. , Benemann John R. 
Published: August 2018

Abstract
Cultures of Anabaena cylindrica, grown on media containing 5 mᴍ NH4Cl (which represses heterocyst formation), evolved hydrogen after a period of dark incubation under an argon atmosphere. This hydrogen production was not due to nitrogenase activity, which was nearly undetectable, but was due to a hydrogenase. Cultures grown on media with tungsten substituted for molybdenum had a high frequency of heterocysts (15%) and inactive nitrogenase after nitrogen starvation. The hydrogenase activity of these cultures was three-fold greater than the activity of non-heterocystous cultures. The effects of oxygen inhibition on hydrogen evolution by hetero-cystous cultures suggest that two pools of hydrogenase activity exist - an oxygen sensitive hydrogen evolution in vegetative cells and a relatively oxygen-resistent hydrogen evolution in heterocysts. In either case, inhibition by oxygen was reversible. Light had an inhibitory effect on net hydrogen evolution. Hydrogen production in vitro was much higher than in vivo, indicating that in vivo hydrogenase activity is limited by endogenous reductant supply.
Chemische Analyse und Struktur des Poliovirus. I. Cystein/Cystin Gehalt, vollständige Aminosäureanalyse und Hydrophobizität von Poliovirus und seinen natürlichen leeren Kapsiden / Chemical Analysis and Structure of Poliovirus. I. Cysteine/Cystine Content, Complete Amino Acid Analysis and Hydrophobicity of Poliovirus and Its Naturally Occurring Empty Capsids
Authors: Heukeshoven Jochen , Demick Rudolf 
Published: August 2018

Abstract
The cysteine content of poliovirus particles and naturally occuring empty capsids was determined by two methods: (1) reaction with vinylpyridine and subsequent amino acid analyses and (2) treatment with 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) and measurement in the change of absorption. Both methods were performed under dissociating conditions in order to expose all sulfhydryl groups. Poliovirus, type 1, strain Mahoney, contains 10-11 cysteine/cystine residues per protomer, irrespective of the use of virus particles or empty capsids. Poliovirus, type 3, strain Saukett, contains 12-13 cysteine/cystine residues per protomer. Poliovirus particles are completely free of disulfide bridges, whereas empty capsids contain 2-4 cystine residues/protomer. No sulfhydryl groups are present on the surface of the virus particle, because of lack of reaction with DTNB.
The tryptophan content was determined to be 13 ± 1 residues/protomer. By amino acid analysis under controlled hydrolyzing conditions 12 residues/protomer were found, whereas formylation in hydrochloric acid/formic acid revealed 14 residues/protomer; 13 tryptophan residues were calculated from the tyrosine-tryptophan relation and the optical density at 293.5 nm and 280 nm.
The following parameters of poliovirus particles were calculated from the improved and complete amino acid analysis and the cysteine and tryptophan content:
1. The molecular weight of a protomer to be 92 700 ± 900 Dalton and of the poliovirus particle, type 1, strain Mahoney, to be 7.97 × 106 Dalton.
2. The relative hydrophobicity of the poliovirus polypeptide to be 1.18.
3. The extinction coefficients of poliovirus E1%
260 = 7 4 and of empty capsids E1%
280 = 16.2 ± 0.2.
An Audiospectrographic Study of Male Stridulation in the Genus Corixa Geoffr. (Hemiptera, Corixidae)
Authors: Finke Christine , Prager Joachim 
Published: August 2018

Abstract
The stridulation signals of three species of the Genus Corixa were investigated especially with respect to their spectral composition. Thee dominant frequencies are: 2.7 kHz for C. panzeri, 2.2 kHz for C. dentipes and 2.0 kHz for C. punctata. For C. punctata the threshold frequency responses, especially for one (A1) of both receptor units of the mesothoracic tympanic organ, correspond well to the frequency spectrum of the emitted sounds.
The Para-O-Methylation of Apigenin to Acacetin by Cell-Free Extracts of Robinia pseudoacacia L.
Authors: Kuroki Gary , Poulton Jonathan E. 
Published: August 2018

Abstract
Crude extracts from young Robinia pseudoacacia seedlings, shoots, and callus tissue catalyze the para-O-methylation of apigenin to acacetin using S-adenosyl-ʟ-methionine as methyl donor. Optimum activity was exhibited at pH 9.0, and Mg2+ was not required for maximum activity. EDTA (10 mᴍ) did not affect the reaction rate, but 47% inhibition was observed with SAH (100 μᴍ). β-Mercaptoethanol (5 mᴍ) was required in the homogenization medium for optimum O-methyltransferase activity. Apigenin (Km, 50 μᴍ) was the best substrate, but significant activity was shown towards caffeic acid, 5-hydroxyferulic acid, naringenin, and quercetin. Paracoumaric, ferulic, and sinapic acids were not methylated. The Km for S-adenosyl-ʟ-methionine was 31 μᴍ. Our demonstration of a para-O-methyltransferase activity methylating apigenin, but not para-coumaric acid, strongly supports the conclusion that the B-ring methylation pattern of acacetin is determined at the C15-level in Robinia pseudoacacia.
Influence of Crystal Packing Forces on Molecular Structure in 4-Thiouridine. Comparison of anti and syn Forms
Authors: Lesyng Bogdan , Saenger Wolfram 
Published: August 2018

Abstract
4-thiouridine crystallizes from butyric acid in the form of yellow needles, monoclinic space group P21 with a = 10.136 (3), b = 4.843 (2), c = 11.257 (3) Å, β = 93.91 (5) °. The crystal structure was solved on the the basis of 895 X-ray counter data using direct methods and refined to a reliability index of R = 5.6%. 4-thiouridine is in the anti conformation, the torsion angle O(1′)-C(1′)-N(1)-C(6) being 26.5°. Pseudorotation parameters τmax = 41.1° and P = 15.7° refer to C(3′)-endo (3E) envelope form of the ribose. The conformation about the C(5′)-O(5′) bond is gauche, gauche.
The present structure is compared with the previous one, crystallized from water as sesquihydrate and existing as the syn conformer (W. Saenger and K. H. Scheit, J. Mol. Biol. 50, 153-169 (1970). The influence of crystal packing forces on flexible molecules such as nucleosides is discussed.
Effect of Vanadate and Iron Stress on the Pigment Composition of Chlorella fusca
Authors: Becker Ludwig J. M. , Meisch Hans-Ulrich 
Published: August 2018

The pigment composition of Chlorella fusca has been investigated in the absence and in presence of vanadate and during iron stress.
1. Fe-deficiency generally decreases algal pigment content without change of the ratio chlorophyll a/b.
2. A twofold vanadate induced increase of the chlorophylls is accompanied by a similar enhancement of several xanthophylls, while lutein remains unaffected.
3. Vanadate stimulates the formation of β-carotene up to 5 fold, the effect being less obvious during iron stress
Light-Induced Accumulation and Stability of Chlorophylls and Chlorophyll-Proteins during Chloroplast Development in Radish Seedlings
Authors: Lichtenthaler H. K. , Burkard G. , Kuhn G. , Prenzel U. 
Published: August 2018

Abstract
Illumination of 3 day old etiolated radish seedlings with continuous white light results in a progressive accumulation of chlorophyll a and b. Both pigments are bound in a different way to the thylakoid chlorophyll-proteins, which appear parallel to the formation of chlorophylls. By applying the SDS-PAGE method to SDS-digested chloroplasts, it was possible to show that the chloroplasts of radish cotyledons contain the typical chlorophyll proteins LHCP1-3, CPa, CPI and CPIa which have been found in other plants. Between LHCP1 and CPI an additional chlorophyll protein is detected with the spectral properties of a LHCP; it is termed here LHCPy.
When the green plants are transferred to continuous darkness, chlorophylls and the chlorophyll-proteins are progressively degraded. At an early stage of greening chlorophyll b is destroyed at a much higher rate in darkness than chlorophyll a, which yields high chlorophyll a/b ratios. This is paralleled by a faster decrease in the level of the corresponding chloro­phyll a/b-protein LHCP3 than of CPI. At a later stage of greening, after the end of the logarithmic chlorophyll accumulation, the chlorophylls a and b and also the LHCP3 and CPI are destroyed in continuous darkness at equal rates; the a/b ratios and the LHCP3/CPI ratios are then little different from the light control.
The data indicate that at an early stage of greening the light-harvesting chlorophyll a/b-protein LHCP3 is less stable than the other chlorophyll-proteins (CPI, CPIa, CPa), which contain pre­ dominantly chlorophyll a.
The ratio chlorophyll a to β-carotene (a/c ratio) of CPIa, CPI and CPa is about 10, while that of the LHCP1-3 is found to be between 150 to 300. We therefore propose using the a/c ratio to define the chlorophyll-proteins which, besides the absorption spectra, is the most suitable parameter.
The Kok Effect and Its Relationship to Photorespiration in Tobacco
Authors: Ishii Ryuichi , Schmid Georg H. 
Published: August 2018

Abstract
The Kok effect of photosynthesis was investigated in different tobacco mutants. It was found that the breaks in the light intensity curve were always at or around 1000 lux in all plants tested regardless of the unit sizes which differed by a factor of 10. It was concluded that the photo­ receptor responsible for the effect must be present in the wild type and the chlorophyll deficient mutants in the same amount and is probably not chlorophyll. Due to the fact that the light dependency of the Hill reaction in isolated tobacco chloroplasts also shows a break at or around the “Kok intensity” it was concluded that probably a structural change of the photochemical apparatus around 1000 lux contributes to the effect. Measurement of 180 2-uptake by mass spectrometry at low light intensity shows at low CO2-concentration an enhancement of 180 2-uptake again at/around 1000 lux indicating that photorespiration starts to function at the “Kok intensity”. Due to the fact that 180 2-uptake remains constant at high CO2-concentrations the break in the photosynthetic light intensity curve cannot be due to an inhibition of “dark respiration” at low light intensities.
Stoffwechselprodukte des 1.2.4-Trihydroxybenzols aus Fruchtkörpern von Gomphidius maculatus und G. glutinosus (Boletales) [1] / Metabolites of 1,2,4-Trihydroxybenzene from Fruiting Bodies of Gomphidius maculatus and G. glutinosus (Boletales) [1]
Authors: Jägers Erhard , Steffan Bert , Ardenne Renata von , Steglich Wolfgang 
Published: August 2018

Abstract
From fruiting bodies of Gomphidius 2,2′,4,4′,5,5′-hexahydroxybiphenyl (7) and a red pigment, gomphilactone (1), have been isolated. The latter may be derived biogenetically from 1,2,4-trihydroxybenzene (6) via oxidative dimerization to 3,5′-dihydroxydibenzoquinone (8) followed by Postemak rearrangement.
Electroreceptors and Direction Specific Arrangement in the Lateral Line System of Salamanders?
Authors: Fritzsch Bernd 
Published: August 2018

Abstract
The arrangement of the lateral line afferents of salamanders as revealed by transganglionic staining with horse­ radish peroxidase is described. Each lateral line organ is supplied by two fibers only. In the medulla these two afferent fibers run in separate fiber bundles. It is suggested, that only those fibers contacting lateral line sensory cells with the same polarity form together one bundle. Bundles formed by anterior or posterior lateral line afferents are also clearly separated. Beside the lateral line organs smaller pit organs are described. These organs are supplied by one afferent only which reveals an arrangement in the medulla different from that of the lateral line afferents. Based on anatomical facts, these small pit organs are considered to be electroreceptors. Centrifugally projecting neurons, most probably efferents, are described in the medulla.