bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intermolecular Interactions of Polypeptides and Lipids in the Thylakoid Membrane
Authors: Menke Wilhelm , Radunz Alfons , Schmid Georg H. , Friederike Koenig , Hirtz Rolf-Dieter 
Published: August 2018

Abstract
Intermolecular interactions between chloroplast lipids and a polypeptide fraction from thylakoids were investigated by far ultraviolet circular dichroism. The polypeptide fraction was isolated from dodecyl sulfate-containing buffers. It exhibits an average molecular weight of 24 000. The circular dichroism of this polypeptide fraction measured as mean residue ellipticity is greater in the presence of sodium dodecyl sulfate than in the absence of this detergent. This effect is reversible. Addition of sulfoquinovosyl diglyceride to the dodecyl sulfate-free solution of the polypeptide also causes an increase of the circular dichroism. This increase was only observed in the pH-range between 6.9 and 7.4. The effect of dodecyl sulfate or sulfolipid on the circular dichroism is interpreted to indicate an increase of α-helix content. Monogalactosyl diglyceride, digalactosyl di­glyceride and phosphatidyl glycerol gave no reaction. The attempt to obtain a conformational analysis of the polypeptide in the different states did not yield an entirely satisfactory result. Antisera to sulfolipid inhibit photosynthetic electron transport of stroma-freed chloroplasts in the region of light reaction I. This inhibition is restricted to the same pH-range as the non-covalent binding of sulfolipid to the polypeptides. It appears that in the cell membrane-bound metabolic processes are regulated by this pH-dependence of the sulfolipid-polypetide interactions.
Struktur-Reaktivitäts-Beziehungen und verzögerte Neurotoxizität organischer Phosphor-Verbindungen / Structure-Reactivity Relationships and Delayed Neurotoxicity of Organophosphorus Compounds
Authors: Reinhardt Hans-Georg 
Published: August 2018

Abstract
A correlation has been found between the reactivity in the alkaline hydrolysis reaction of a new series of organophosphates and their ability or disability to produce the clinical manifestation of delayed neurotoxicity in hen. At a dose of 1000 mg/kg only compounds exceeding a lower limit of reactivity (about 6×10-2м-1s-1) are active.
Verteilung von [3H]Thiopyronin in Hefezellen (Saccharomyces cerevisiae) / Distribution of [3H]Thiopyronine in Yeast Cells (Saccharomyces cerevisiae)
Authors: Lochmann Ernst-Randolf , Herrmann Cornelia , Pietsch Ingrid , Micheler Astrid 
Published: August 2018

Abstract
After incubation of Saccharomyces cells in [3H] thiopyro­ nine solution the photodynamically high effective dye was detected only to about 1% in the nucleus of the cell. 99% of the dye is distributed in the cytoplasm.
Detachment of Segments from DNA Double Strands as Detected by Time Resolved Rayleigh Light Scattering
Authors: Lindenau D , Hagen U , Schnabel W 
Published: August 2018

Abstract
Calf thymus DNA was irradiated in oxygen saturated 0.01 N NaCl solution with 2 μs pulses of 15 MeV electrons. By monitoring the decrease of light scattering intensity after the pulse, two modes of decrease were detected: The fast decrease (τ½ ≈ 0.8 ms) is ascribed to the separation of DNA fragments produced by double strand breaks at positions directly opposite to each other. The slow decrease (τ½ ≈ 8s) is attributed to the detachment of segments generated by single strand breaks at sites on the alternate strands being separated by about 10 nucleotide units.
β-Cyclocitral and Alkanes in Microcystis (Cyanophyceae)
Authors: Jüttner Friedrich 
Published: August 2018

Abstract
A tobacco-like odorous compound isolated from a bloom of the blue-green alga Microcystis wesenbergii and a laboratory culture of M . aeruginosa was analysed by gas-liquid chromatography and mass spectrometry. Its structure was determined as β-cyclocitral. No other monoterpenes have been detected in these and in other blue-green algae. The hydrocarbon content was 0.10 - 0.18% of the dry weight. n-Hexadecane, n-heptadecane, 4-methylheptadecane and n-octadecane constituted the main components. The relation of the different alkanes to each other, especially 4-methylheptadecane and n-octadecane, revealed marked differences in the two organisms.
The Influence of Oxygen on Nitrite Reduction in a Reconstituted System
Authors: Spiller Hartmut , Bookjans Gerhard , Böger Peter 
Published: August 2018

Abstract
Data regarding the role of oxygen in nitrite reduction are presented. In an NADPH-generating system including homogeneously purified ferredoxin-NADP reductase, ferredoxin (or flavodoxin) and nitrite reductase from the alga Bumilleriopsis filiformis, oxygen and nitrite can be reduced simultaneously. In air, rates of 1.2 μmol nitrite reduced· min-1· mg -1 nitrite reductase are ob­tained, which are physiologically feasible. Ferredoxin is inhibited non-competitively by oxygen during nitrite reduction. Oxygen uptake due to the oxidase reaction of ferredoxin-NADP reductase mediated by flavodoxin from Chlorella fusca and ferredoxin from Bumilleriopsis involves superoxide and is inhibited by the nitrite reducing system.
Effect of an Antiserum to a Thylakoid Membrane Polypeptide on the Primary Photoreaction of Photosystem II
Authors: Schmid Georg H. , Renger Gernot , Gläser Michael , Koenig Friederike , Radunz Alfons , Menke Wilhelm 
Published: August 2018

Abstract
As was described previously, an antiserum to polypeptide 11000 inhibited photosynthetic elec­tron transport on the oxygen evolving side of photosystem II. The effect of the antiserum on chloro­plasts from two tobacco mutants also clearly showed that the inhibition site is on the photosystem II-side of the electron transport chain. One of the two tobacco mutants lades the oxygen evolving capacity but exhibits some electron transport with tetramethyl benzidine, an artificial donor to PS II. In this mutant electron transport was barely inhibited. The effect of the antiserum on the primary photoevents showed that the initial amplitude of the absorption change of chlorophyll an at 690 nm and that of the primary electron acceptor X320 at 334 nm both diminished in the presence of the antiserum. Both signals were restored upon addition of diphenylcarbazide another artificial donor to photosystem II. Comparison of the degree of inhibition on the amplitudes of the fast and slow components of the 690 nm absorption change with the manometrically measured inhibition of electron transport shows that besides a full inactivation of a part of the reaction centers of photosystem II another part apparently mediates a fast cyclic electron flow around photosystem II as reported by Renger and Wolff earlier for tris-treated chloroplasts. Moreover, the antiserum affects the low temperature fluorescence in a way which is opposite to Murata’s effect of the Mg2+ -ion induced inhibition of energy spill-over from photosystem II to photosystem I. The antiserum under the condition in which the Hill reaction is inhibited lowered the 686 nm emission and enhanced the 732 nm emission which indicates an enhanced energy spill-over to photosystem I.
Spurenanalytik von p-Benzochinon-und Hydrochinon-Derivaten mit Gaschromatographie und Gaschromatographie/Massenspektrometrie. Identifizierung von Wehrsekret-Komponenten europäischer Juliden / Trace Analysis of p-Benzoquinone-and Hydroquinone Derivatives by Gas-Liquid Chromatography and Gas-Liquid Chromatography/Mass-Spectrometry. Identification of Defensive Secretion Components from European Julids
Authors: Röper Harald , Heyns Kurt 
Published: August 2018

Substituted p-benzoquinones (= quinones) and substituted hydroquinones [bis-trimethylsilyl- ethers or bis-trifluoroacetates] can be separated by gas-liquid chromatography using 50 meter long thinfilm capillaries (inner diameter: 0.25 mm) coated with silicone OV 17 (50% phenyl, methyl) or silicone DC 550 (25% phenyl, methyl).
Total retention times of various derivatives of p-benzoquinone and hydroquinone were deter­mined.
Complex model mixtures of these derivatives can be separated by gas-liquid chromatography with temperature programs and the individual components can be clearly identified by their mass spectra in the sub microgram range by using combined gas-liquid chromatography/mass-spectrometry. This microanalytical technique was applied to identify the defensive secretion components from members of the diplopod order Julida (Arthropods). Julus nitidus produces a defensive secretion that consists exclusively of 2-methyl-3-methoxyquinone. The expelled defensive secretions of Unciger foetidus, Cylindroiulus coeruleocinctus (Iondinensis), Cylindroiulus punctatus, Cylindroiulus luridus and Ophyiulus psilosus consist of a 2-methylquinone and 2-methyl-3-methoxyquinone mixture. The presence of the corresponding hydroquinones-2-methyl-hydroquinone and 2-methyl-3-methoxyhydroquinone-was also determined in all cases.
Reconstitution of a System for H2 Evolution with Chloroplasts, Ferredoxin, and Hydrogenase
Authors: Fry Ian , Papageorgiou George , Tel-Or Elisha , Packer Lester 
Published: August 2018

Continuous light-dependent H2 production was studied in a reconstituted in vitro system using Spinacea oleracea chloroplasts, Clostridium pasteurianum hydrogenase and Spirulina maxima ferredoxin. PhotosystemII dependent production at 30 0C is 60 -70 μmol H2/mg chlorophyll. At 15 0C, this reaction proceeds for up to 20 h producing 1O μmol H2/mg chlorophyll. O2 (glucose, glucose oxidase) and peroxide (ethanol, catalase) traps do not extend the lifetime but enhance the rate of H2 production. Stoichiometry of the coupled system for H2 production in this system is 2 H2 formed : 1 glucose consumed. A conversion efficiency of water photolysis for H2 evolution of 70% was determined from the O2 produced, measured as the amount of glucose consumed, during the first 2 h of continuous illumination.
Cessation of H2 production by the reconstituted system involves inactivation of photosystem II and a limitation in the coupling of low potential electrons to hydrogenase. Increasing ferredoxin leads to more rapid H2 evolution but longevity of the system remains unchanged. When H2 evolution ceases due to inactivation of water-splitting activity of photosystem II, about 40% of the hydro­genase and 25% of photosystem I activity are still present; inactivation is unclear when photo­system I is used to drive H2 production since when H2 production ceases, hydrogenase and photo­system I still retain activity. This may suggest that coupling between low potential reducing equivalents from photosystem I to hydrogenase is impaired.
Notizen: Fluorescence and Membrane-Action of Tetracaine
Authors: Elferink J. G. R. 
Published: August 2018

Abstract
Tetracaine, Fluorescence, Erythrocyte Membrane The fluorescence of tetracaine depends on the micro-environment of the molecule and increases with increasing hydrophobicity. The presence of erythrocyte membranes strongly enhances tetracaine fluorescence. The results support the view that the alkyl chain and aromatic part of tetracaine is embedded in apolar regions of the lipid or protein phase of the membrane.
Schadstoff-Untersuchungen an datierten Sedimentkernen aus dem Bodensee / Pollution Research on Dated Sediment Cores from Lake Constance
Authors: Müller German 
Published: August 2018

Abstract
The vertical distribution of eight heavy metals (Hg, Cu, Zn, Cr, Co, Ni, Pb, Cd) in dated sediments of four sedimentary profiles from the central part of Lake Constance was examined. From 1900 to about 1960 - 1970, a general increase of all heavy metals was observed. After this time, the concentrations of most of the metals decreased.
As compared with pre-1900 “natural” metal concentrations, Cd and Pb have been enriched the strongest (enrichment factors 4.0 and 3.8 resp.), whereas Ni and Co exhibit least civilizational influences (enrichment factors 1.5 and 1.9 resp.). Cu, Cr, Zn and Hg were enriched by a factor between 2 - 3. Elements which were not influenced by anthropogenic processes - such as K and Li - remained unaffected over the whole vertical sequence. Polycyclic aromatic hydrocarbons (PAH) which were also studied in the same sediment material by Grimmer and Böhnke show a similar pattern. Within a sedimentary profile the concentration ratio benzo (a) pyrene: cadmium remained about constant.
Combustion of coal is believed to be the common source of both heavy metals and PAH and seems to be responsible for the general distribution pattern of both groups of pollutants. In addition, local sources - both domestic and industrial - are assumed to have delivered additional heavy metal pollution.
The Quaternary Structure of Yeast Aminopeptidase I
Authors: Marx Ruth , Metz G. , Röhm K.-H 
Published: August 2018

Abstract
Aminopeptidase, Yeast, Electron Microscopy, Quaternary Structure Electron micrographs of native aminopeptidase I and of isolated subfragments were taken after negative staining with uranyl formate. From these studies and from the chemical evidence sum­ marized in the preceding paper it is concluded that the active enzyme is a dodecamer possessing pseudo-D3 symmetry with the dimer as the smallest symmetric unit.
Characterization of a Soluble NADH-Independent Nitrate Reductase from the Photosynthetic Bacterium Rhodopseudomonas capsulata
Authors: Alef Kasem , Klemme Jobst-Heinrich 
Published: August 2018

Abstract
The assimilatory nitrate reductase was purified 60-fold from a newly isolated, nitrate assimilating strain of the photosynthetic bacterium Rhodopseudomonas capsulata. The enzyme had a molecular weight of about 180 000 dalton and was typically prokaryotic in that it was not active with reduced pyridine nucleotides but rather with reduced flavins.
On the Correlation between the Amplitude of the Electrochromic Absorption Changes and the Number of Bulk Pigments
Authors: Renger Gernot , Schmid Georg H. 
Published: August 2018

Abstract
Electrochromic Absorption Changes, Photosynthetic Unit A correlation between the amplitude of the electrochromic absorption changes measured at 480 nm and 520 nm and the size of the photosynthetic unit is found. Three tobacco mutants which differ with respect to their photosynthetic unit size exhibit decreased amplitudes of the electrochromic absorption changes which parallel the size of the photosynthetic units. Under these conditions the ATP-yield per flash is unaffected by the photosynthetic unit size. From this it is deduced that the correlation between the amplitude of the electrochromic absorption change and the photosynthetic unit size is due to the fact that the number of pigments undergoing an electro­ chromic bandshift is proportional to the total pigment content. As the influence on the electro­ chromic effect at 520 nm is too pronounced as to be simply explainable by the variation of the carotenoid content in the different mutants it is inferred that either structural effects leading to a modification of the carotenoid orientation in the mutants or an indirect influence of chlorophyll on the electrochromic bandshift which depend on the number of chlorophyll molecules are responsible.
Chemische und biochemische Charakterisierung von α-Benzyl-α-brommalonitril (BBMD) als Oxidationsmittel / Chemical and Biochemical Characterization of α-Benzyl-α-bromo-malononitrile (BBMD) as Oxidizing Agent
Authors: Rieser J. , Höckendorf A. , Abou-Elenien G. , Wallenfels K. 
Published: August 2018

Abstract
The behaviour of α-benzyl-α-bromo-malononitrile (BBMD) as oxidizing agent was characterized. The dependence of the electrochemical reduction potentials of BBMD on the pH-values of the solutions was examined. BBMD is reduced in a two-electron wave with half-wave potentials between + 230 and + 312 mV vs. Ag/AgCl/Cl-. BBMD is able to oxidize different organic compounds with OH-, SH-, NH- and CH- groups as well as a series of biological reducing agents as ubihydroquinone, plastohydroquinone, dihydro-lipoic acid, FADH2, NADPH and NADH. In all these cases BBMD is reduced to benzylmalononitrile. Kinetic investigations of this reduction process using NADH as reducing agent and also NMR-investigations using deuterated NADH-models showed that BBMD is directly reduced to benzylmalononitrile without producing benzylidenemalononitrile as intermediate. The reduction of BBMD with reduced pyridine nucleotides as well as that of benzylidene­ malononitrile were accelerated by an enzyme which was concentrated from human erythrocytes, using 2-chloro-benzylidenemalononitrile (CS) as substrate.
Chemical Investigation of the Lichen Species Alectoria ochroleuca, Stereocaulon vesuvianum var. pulvinatum and Icmadophila ericetorum
Authors: Solberg Yngve 
Published: August 2018

Abstract
Lichens, Lipids, Phenols The three lichen species Alectoria ochroleuca, Stereocaulon vesuvianum var. pulvinatum and Icmadophila ericetorum have been chemically investigated with regard to their content of aliphatic and aromatic compounds. Tetrahydroxy fatty acids were isolated in all three species. A mono-acetylated pentol, higher fatty acids and an unsaturated triglyceride were detected as new con­ stituents of A. ochroleuca and I. ericetorum. S. vesuvianum and I. ericetorum both contained phenolic components which not previously have been discussed in literature. Chemical and spectro­ scopic evidences are presented in these studies.
Labelling Experiments on the Origin of Hexa-and Octa- decatrienoic Acids in Galactolipids from Leaves
Authors: Siebertz H. P. , Heinz E. 
Published: August 2018

Abstract
Young leaves from three plants which accumulate hexadecatrienoic acid rather specifically in the sn-2-position of monogalactosyl diglyceride (MGD) were incubated with radioactive CO2 or acetate to investigate the origin of this specificity. Labelled glycerolipids were extracted and analyzed for time-dependent changes of radioactivity in their fatty acids. The investigation of labelled MGD and digalactosyl diglyceride (DGD) included determination of radioactivity in hydrolysis products, separation of molecular species by argentation chromatography and analysis of the positional distribution of fatty acids. The results agree with previous observations on the accumulation of radioactive oleic acid in phosphatidyl choline (PC) and formally with the possibility of a PC-coupled desaturation to linoleic acid. They do not support the proposed function of PC as donator of polyenoic acids. Instead the radioactivity patterns may be interpreted as pointing to a relation between fatty acid desaturation and many if not all glycerolipids, although a different interpretation is also possible.
Fatty acid patterns in lipids and their labelling indicate the existence of several pools for
1) MGD, from which only that without C16-unsaturated fatty acids is accessible for galactosylation to DGD ;
2) palmitic acid, from which one part is accessible to desaturation via C16:0 and C16:2 to C16:3 . Since these acids are found labelled in the sn-2-position of MGD, the specific positioning may be related to this separation of C16:0pools. Desaturation of C16:0 seems to be the major source of C16:3;
3) linolenic acid, from which those parts present in the sn-2-position of galactolipids or in PC are characterized by a strikingly slow labelling.
Biflavones from the Leaves of Araucaria rulei F. Muell. and a Survey on Biflavanoids of the Araucaria Genus
Authors: Ilyas M. , Seligmann O. , Wagner H. 
Published: August 2018

Abstract
Eleven biflavones have been isolated from the leaves of Araucaria rulei and identified by NMR spectroscopy and via the permethylated and peracetylated products. The biflavones found until now in the Araucaria genus are summarized in a table.
Inhibition of Human Prolyl Hydroxylase as Common Biochemical Denominator of the Non-Sedative Effects of Thalidomide in Man
Authors: Hanauske-Abel Hartmut , Günzler Volkmar 
Published: August 2018

Abstract
The two main non-sedative effects of thalidomide (2-phtalimido-glutarimide) in man are the embryopathy, which finally forced termination of its use as a sedative, and the excellent efficacy in leprosy reactions, alone for whose prevention and treatment the drug is still available. Both effects can be explained on a molecular level by assuming that a non-sedative metabolite of thalidomide mediates inhibition of human prolyl hydroxylase, as suggested by steric considerations and correlation to known data. This metabolite may well be a suitable model compound for drugs designed for selective fibrosuppression and selective immunosuppression.
Competition between Oxalate and Phosphate during Active Calcium Accumulation by Sarcoplasmic Vesicles
Authors: Beil Frank-Ulrich , von Chak Dorothee , Hasselbach Wilhelm , Weber Hans-Hermann 
Published: August 2018

Abstract
Sarcoplasmic Calcium Uptake, Oxalate and Phosphate Uptake, Oxalate-Phosphate Competition, Calcium Turnover
1. During ATP supported active calcium uptake oxalate as well as phosphate are accumulated with calcium. The uptake of calcium exceeds that of both anions by a small quantity - accounting for calcium binding to vesicular proteins and lipids.
2. From assay media containing phosphate and oxalate - nearly exclusively either oxalate or phosphate are taken up together with calcium by the sarcoplasmic reticulum vesicles. The mutual exclusion occurs in a very narrow concentration range of the anions.
3. In solutions containing phosphate and oxalate, calcium phosphate or calcium oxalate pre­ cipitates are formed according to their solubility properties.
4. When phosphate prevents oxalate from being taken up, calcium transport is inhibited. In­ hibition occurs, because the concentration of ionized calcium inside the vesicles rises approximately 100-fold when oxalate is replaced by phosphate. The activity of the calcium dependent ATPase parallels the calcium uptake activity.
5. It is excluded that the inhibition of calcium uptake produced by phosphate is caused by an enhanced permeability of the sarcoplasmic reticulum membranes for calcium in the presence of phosphate.
Identification of Essential Histidine Residues of Aminoacylase by Photooxidation and by Reaction with Diethylpyrocarbonate
Authors: Kordel Werner , Schneider Friedhelm 
Published: August 2018

Abstract
State and function of the histidine residues of aminoacylase were investigated by photooxidation in the presence of methylene blue and by chemical modification with diethylpyrocarbonate. Complete inactivation of the enzyme was observed after oxidation of 4 histidine residues. From the pH dependence of the photooxidation it becomes evident that the inactivation of the enzyme is not a consequence of the simultaneous oxidation of tryptophan residues. The enzyme is also inctivated by chemical modification of histidine residues with diethylpyrocarbonate. Activity is restored by treatment with hydroxylamine. Zn2+-ions which are essential for the activity of amino­ acylase protect the available histidine molecules against photooxidation and attack by diethyl­ pyrocarbonate. It is suggested that histidine is involved in the binding of the essential Zn2+-ions.
The Biosynthesis of Phenylacetic Acids in the Blue-Green Alga Anacystis nidulans: Evidence for the Involvement of a Thylakoid-Bound ʟ-Amino Acid Oxidase
Authors: Löffelhardt W. 
Published: August 2018

Abstract
Phenylacetic acid and p-hydroxyphenylacetic acid are formed upon incubation of photosynthetic membranes from the prokaryotic alga Anacystis nidulans with ʟ-phenylalanine and ʟ-tyrosine, respectively. The corresponding phenylpyruvic acids act as intermediates as shown by trapping them as the stable oximino acids. The first step in this reaction sequence appears to be catalyzed by a thylakoid-bound ʟ-amino acid oxidase. Already existing evidence concerning phenylacetic acid formation at thylakoid membranes of higher plants via an ʟ-amino acid oxidase and the results obtained with A. nidulans give another example of aromatic amino acids between chloroplasts and blue-green algae.