bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrophoretic and Chemical Studies on the X-Ray Damage of Malate Synthase
Authors: Durchschlag Helmut , Zipper Peter
Published: August 2018

The sulfhydryl enzyme malate synthase was shown to undergo an X-ray induced aggregation and inactivation in solution (Zipper and Durchschlag, Radiat. Environ. Biophys. 18, 99-121 (1980)). Further evidence for the occurrence of aggregation and inactivation and also of fragmen­ tation and partial unfolding of the enzyme upon X-irradiation was obtained by chemical and electrophoretic studies. Irradiation was carried out in a specially designed microcell, experiments were performed on the microlevel. Under conditions of the experiments the formation of H2O2 upon X-irradiation could be proven; therefore the influence of H2O2 on the enzyme was investigated too. Though the quantitative results of the damaged enzyme particles are influenced by many disturbing factors, the findings allow clear statements on the nature of the effects under investigation.

1) Both X-irradiation and treatment with H2O2 caused a decrease of total and an increase of available sulfhydryl groups of the enzyme and led to a loss of enzymic activity. The presence of dithiothreitol turned out to be able to protect the enzyme against X-ray or H2O2 induced inactivation. Moreover, addition of dithiothreitol after X-irradiation or H2O2 treatment allowed a considerable repair of enzymic activity.

2) Polyacrylamide gel disc electrophoreses of X-irradiated enzyme solutions, performed in the presence of sodium dodecyl sulfate, showed the occurrence of covalently cross-linked subunits (preferably dimers and trimers) and of various definite fragments. Electrophoreses in the absence of the denaturant indicated the occurrence of enzyme aggregation. The effects were more pronounced with increasing X-ray doses. The electrophoreses also clearly reflected a radioprotec­ tion by dithiothreitol against cross-linking, but not against fragmentation. Addition of excess of 2-mercaptoethanol or of dithiothreitol to the X-irradiated enzyme clearly demonstrated that part of the covalent cross-links were disulfide bridges; the aggregates themselves, however, were held together primarily by non-covalent bonds. Blocking of exposed enzyme sulfhydryls by means of Ellman's reagent prevented both covalent cross-linking and enzyme aggregation.

3) Similar electrophoretic patterns as found for the X-irradiated enzyme were obtained for the unirradiated enzyme after treatment with H2Oi. The similarity of the electropherograms, as well as the reversible diminution of enzymic activity and the loss of sulfhydryls in the presence of H2O2, suggest an involvement of H2O2 in the radiation damage of the enzyme. It seems plausible that oxidation reactions are responsible for the effects caused by X-irradiation or H2O2 treatment.
18O-Exchange by Hydrolyzing Enzymes: Extension of the Model to Pi Molecules with Inequivalent Oxygen Atoms in the Bound State
Authors: Rösch Paul
Published: August 2018

Enzymes causing an exchange of oxygens from P\ with the surrounding water oxygens are very common. A statistical model for the data evaluation for an observation of this oxygen exchange by isotope methods is presented. It is shown how different cases of inequivalence of the four Pi oxygens may be uncovered. The number of reversals of the oxygen exchange step on the enzyme and the apparent second order rate constant for the binding of Pi to the enzyme are obtained as a result of the data fitting procedure. Cobalt phosphatase, zinc phosphatase, and myosin subfragment 1 are treated as examples.
Protein Kinases in HeLa Cells and in Human Cervix Carcinoma
Authors: Pyerin W. , Baibach N. , Kübler D. , Kinzel V.
Published: August 2018

Extracts of HeLa cell fractions were analyzed by DEAE-and phospho-cellulose chromatog­ raphy for their range of cyclic AMP-dependent and -independent protein kinase activities phosphorylating histone and/or phosvitin; extractions were by phosphate buffered saline (soluble protein kinases) and the non-ionic detergent NP-40 (membrane-bound protein kinases). The soluble fraction contained (i) cyclic AMP-dependent histone kinases type I and II as evidenced by their behaviour on DEAE-cellulose and inhibition by the specific heat-and acid-stable protein kinase inhibitor (PKI) in a dose-related manner; both types I and II as well as their purified catalytic subunit also phosphorylated protamine and — with very low efficiency -casein but not phosvitin; (ii) a histone kinase (H), insensitive to cyclic AMP and PKI, also accepting protamine as substrate but not either casein or phosvitin; (iii) a phosvitin kinase (P), insensitive to cyclic AMP and PKI, which also phosphorylates casein but not histone or protamine. These four enzyme species were also found in NP-40 extracts of 27000x g residues which, however, contained further histone and phosvitin kinase activities as yet unspecified. NP-40 extracts of the microsomal fraction possessed, besides unspecified histone and phosvitin kinase activity, only the phosvitin kinase P and appeared to be devoid of histone kinases I, II, and H. The occurrence and ratios of the protein kinases classified suggest an ordered distribution over the diverse subcellular fractions of HeLa cells. The overall pattern of soluble and membrane-bound histone and phosvitin kinases in extracts of cervix carcinoma tissue, the in vivo correlate of HeLa cells, closely resembled that of similar extracts of HeLa cells. HeLa cells hence appear, despite their long in vitro history, to express protein kinase activities similar to those of their in vivo ancestors, recommending them as a subject for the study of (certain) human protein kinase systems.
On the Specificity of Juvenile Hormone Biosynthesis in the Male Cecropia Moth
Authors: Peter Martin G. , Shirk Paul D. , Dahm Karl H. , Roller Herbert
Published: August 2018

The accessory sex glands (ASG) of adult male Cecropia contain an enzyme that methylates juvenile hormone acids (JH-acids) in the presence of S-adenosyl-L-methionine (SAM). The methyltransferase is highly specific. The reaction rates decrease in the order JH-I-acid, JH-II-acid and JH-III-acid; in each case the natural enantiomer is esterified predominantly. Methyltrans­ ferase activity with the same substrate specificity was also demonstrated in adult female corpora allata (CA). Male CA have only marginal methyltransferase activity. The CA of male H. cecropia contain substantial amounts of JH-I-acid and JH-II-acid (minimum: 5 pmol/pair). When kept in organ culture, they release JH-acids into the medium. Radiolabeled propionate and mevalonate are incorporated efficiently into the carbon skeletons of the JH-acids. The enzyme system performing these transformations cannot be forced to produce JH-III-acid even in the presence of high mevalonate concentrations, though homomevalonate may enhance biosynthesis of JH-I-acid and JH-II-acid more than tenfold. It becomes evident that the regulation of JH titer balances with regard to the homologous structures during insect development is not merely a question of the availability of low molecular weight precursors, but in addition that of highly specific enzymes acting as regulatory entities in the later steps of the biosynthetic sequence.
Iridoide aus einigen Teucrium-und Ajuga-Arten / Iridoids in Some Teucrium and Ajuga Species
Authors: Ruhdorfer Johann , Rimpler Horst
Published: August 2018

of the genus Teucrium and 3 species of the genus Ajuga have been examined for iridoids. Besides the known compounds Harpagid, 8-O-Acetylharpagid, Ajugol, Ajugosid and Reptosid, which we have isolated from species of both genera, two new iridoids Teucardosid (1) [2] and Teuhircosid (5) have been isolated from Teucrium species only. The structure and relative configuration of the new compounds have been determined by spectroscopic methods fH-NMR, 13C-NMR, MS) and some chemical reactions. The taxonomic significance of our results is discussed.
Ferulic Acid-Sucrose Esters from Immature Anthers of Tulipa cv. "Apeldoorn"
Authors: Strack Dieter , Sachs Gesine , Römer Axel , Wiermann Rolf
Published: August 2018

Two ferulic acid conjugates have been isolated from the extract of immature anthers of Tulipa cv. "Apeldoorn" and their structures elucidated using chromatography, electron impact mass spectrometry, and NMR spectroscopy. These two conjugates are 6,3'-diferuloylsucrose and 6,3',4'-triferuloylsucrose. High performance liquid chromatographic analysis of the extract showed that these esters are transient major constituents of the phenylpropanoid pattern of the immature anthers and are present in the ratio of 1:2. Previous investigations showed that these components are accumulated in the loculus.
Über die Zusammensetzung des ätherischen Öls aus Artemisia dracunculus L. während der Vegetationsperiode / On the Composition of the Essential Oil from Artemisia dracunculus L. during the Vegetation Period
Authors: Vostrowsky Otto , Michaelis Karl , Ihm Helmut , Zintl Robert , Knobloch Karl
Published: August 2018

The main components of the essential oil from Artemisia dracunculus L., as there are sabinene, methyl eugenol, estragol and elemicine, are present in variable quantities depending on the season. The biosynthesis of the phenolic compounds in tarragon is in accordance with the shikimate pathway. Elemicine is likely to be a metabolic product of shikimic acid with no further mono-or bisphenolic intermediates involved.
Conversion of Flavanone to Flavone, Dihydroflavonol and Flavonol with an Enzyme System from Cell Cultures of Parsley
Authors: Britsch L. , Heller W. , Grisebach H.
Published: August 2018

Soluble enzyme preparations from irradiated cell suspension cultures of parsley (Petroselinum hortense Hoffm.) catalyse the conversion of flavanone to flavone, dihydroflavonol and flavonol. These reactions require 2-oxoglutarate, Fe2+ and ascorbate as cofactors. In the presence of these cofactors conversion of dihydroflavonol to flavonol was also observed. With this system in vitro biosynthesis of radioactive flavone, dihydroflavonol and flavonol from [2-14C]malonyl-CoA and 4-coumaroyl-CoA in good yield and with high specific activity is possible.

We postulate that synthesis of flavone and flavonol from flavanone proceeds via 2-hydroxy-and 2,3-dihydroxyflavanone, respectively, with subsequent dehydration.

The microsomal fraction of the parsley cells contains an NADPH-dependent flavanone 3'-hydroxylase.
Co+2-Substituted Acylamino Acid Amido Hydrolase from Aspergillus oryzae
Authors: Gilles Ingrid , Löffler Hans-Gerhard , Schneider Friedh.
Published: August 2018

Dedicated to Prof. H. Zahn on the Ocassion of His 65th Birthday Zn+2/Co+2 Exchange, Microbial Acylamino Acid Amido Hydrolase, Aspergillus oryzae, Kinetic Properties The inactivation of the Zn+2 metallo enzyme acylamino acid amido hydrolase from Aspergillus oryzae by ethylendiamine-tetraacetate (EDTA) and nitrilotriacetate (NTA) and the effects of Phe and His on this process were studied. Reactivation of the enzyme by Zn+2-or Co+2-NTA buffer revealed a dissociation constant for the Zn+2-enzyme of 10~10 M and for the Co+2-enzyme of 10-7-5 m. The kinetic properties of the Zn+2 and Co+2 enzyme were compared for a series of substrates. Substitution of Co+2 for Zn+2 reduces substrate specificity of the enzyme.
Cadmium — ein Wachstumsfaktor für den Schiefknolligen Anischampignon Agaricus abruptibulbus (Peck) Kauffmann / Cadmium as a Growth Factor for the Mushroom Agaricus abruptibulbus (Peck) Kauffmann
Authors: Meisch Hans-Ulrich , Scholl Anne-Ruth , Schmitt Johannes A.
Published: August 2018

of Agaricus abruptibulbus, a mushroom which is known to accumulate cadmium, has been isolated and cultivated under definite conditions on agar plates or in a liquid medium in the absence and in presence of cadmium acetate. In.presence of 0.5-1.0 mg/1 Cd, mycelial growth of A. abruptibulbus is enhanced to 80% compared to the Cd-free controls, while above 4 mg Cd/1, the metal began to be inhibitory. The growth promoting effect of Cd was found to be independent from the supply of the organism with zinc.

During growth in presence of Cd, an efficient uptake of the metal into the mycelium took place, a maximal 300 fold enrichment being observed with 10 mg Cd/1. Similar tests were performed with zinc, thereby showing a correlation between the uptake of both elements by the mushroom.
Two Sites of Inhibition of the Photosynthetic Electron Transport Chain by the Herbicide Trifluralin
Authors: Droppa Magdolna , Demeter Sándor , Horváth Gábor
Published: August 2018

The effect of trifluralin on the photosynthetic electron transport has been investigated by oxygen evolution and thermoluminescence m easurem ents. The results confirm the earlier observations that trifluralin at low concentrations blocks electron transport between the two photosystems probably at the same site as DBMIB does. At higher concentrations however, trifluralin inhibits the reaction from H2O →pBQ also and affects the thermoluminescence of chloroplasts in a manner sim ilar to DCMU. These results suggest that trifluralin has a second inhibitory site therefore the use of trifluralin as a specific inhibitor of electron transport has to be questioned.
Light-Dependent Changes in the Lipid and Fatty Acid Composition of Phycocyanin-Free Photosynthetic Lamellae of Synechococcus
Authors: Datz Günter , Döhler Günter
Published: August 2018

The growth of Synechococcus at different intensities of white and red light caused changes in the pigment composition. The ratio of chlorophyll a to phycocyanin varied from 1:8,2 in LWLI-grown cells to 1:1,4 in cells grown at HWLI and to 1:15,7 in cultures exposed to HRLI. Acyl lipids were quantitatively determ ined and fatty acids of the individual lipid classes analysed by GLC. Phycocyanin-free photosynthetic lam ellae were obtained by fractional centrifugation. No variation was found in the acyl lipid composition of the m em brane preparations. These all contained MGDG, DGDG, SQDG and PG as components. In all the lipids investigated, palmitic, hexadecenoic and octadecenoic acids m ade up to more than 90% of total fatty acids. The pattern of these major components w ithin the lipids from the different cultures depended on the light used. No large differences were detected between zones obtained from LWLI and HRLI isolated membranes, whereas density gradient centrifugation of those from HWLI-grown cells resulted in a completely different pattern of bands. The variations in lipid and fatty acid composition are discussed with respect to changes observed in lipid composition of whole cells and the results reported on tem perature dependent shifts in lipid fluidity in cyanobacteria.
X-Ray Studies on Phospholipid Bilayers I. Polymorphic Forms of Dimyristoyl Lecithin
Authors: Suwalsky M. , Tapia J.
Published: August 2018

A structural study of the synthetic phospholipid, L-a-dimyristoyl lecithin (DM L), has been m ade by X-ray fiber diffraction methods. Three different types of oriented specimens were prepared. They were X-ray photographed under the same conditions, including tem perature and relative humidity. T hree different types of diffraction patterns, corresponding to different confor­ mations and/or packing arrangements, were found. They are characterized by their unit cell dimensions, space groups, molecular conformations, and packing arrangements.
Titration of Rat Liver with Digitonin: a Well Defined Short Term Damage of Cellular Metabolism
Authors: Postius Stefan , Platt Dieter
Published: August 2018

Carefully performed pulse titration of the isolated rat liver in the course of continuous erythro­ cyte free perfusion with small amounts of digitonin causes a short term perm eability of liver cell plasma membranes with concomitant short lived release of intracellular low or high molecular compounds such as ATP or lactate dehydrogenase. Gluconeogenesis from lactate being completely inhibited during this period restores w ithin about one m inute up to a level that depends on the am ount of perfused digitonin. The described experimental m odel is suggested to be useful for the measurement of cytoplasmic m etabolites under physiological conditions. It moreover offers the possibility to im port foreign substances into liver cells th at normally do not penetrate liver cell plasma membranes.
Natürliche Hemmstoffe von Keimung und Wachstum, I Ausarbeitung eines quantitativen Biotests und Anwendung auf Extrakte aus Spelzen von Avena sativa L. / Natural Inhibitors of Germination and Growth, I. Development of a Quantitative Biotest and Application upon Extracts from Husks of Avena sativa L.
Authors: Karl Rudolf , Rüdiger Wolfhart
Published: August 2018

Extracts from oat husks inhibit germination of a variety of seeds including Avena sativa L., Sorghum spec., Phalleris spec., Raphanus spec., Amaranthus caudatus, Lepidium sativum L. A quantitative assay for this inhibition was developed on the basis of percentage of root growth of Avena in the presence of extracted material compared with root growth of water controls. Fractionation of the extracts revealed that about half of the total inhibitory activity was found in the fraction of free organic acids. The inhibition was not due to known inhibitors. Abscisic acid. was not found in this extract. Phenole carbonic acids were determined in the extract. Their con­centration was too low to significantly contribute to the observed inhibitory activity.
Natürliche Hemmstoffe von Keimung und Wachstum II Isolierung und Struktur von Hemmstoffen aus , Avena sativa L.+ / Natural Inhibitors of Germination and Growth II Isolation and Structure of Inhibitors from Avena sativa L
Authors: Lohaus Edith , Bios Inge , Schäfer Wolfram , Rüdiger Wolfhart
Published: August 2018

Extracts from oat husks which inhibit germination of a variety of seeds were fractionated. After mild alkaline hydrolysis, two active fractions A1 and A2 were obtained. From A1 which contains mainly aliphatic di- and tricarboxylic acids, the inhibitor was isolated by chromatographic procedures and identified as 1,3,4-pentanetricarboxylic acid (11 b) by mass spectrometry. The structure was confirmed by total synthesis of the compound in the form of a mixture of diastereomers 11 a/11 b. From A2, two aromatic compounds were isolated by chromatography and identified by gas chromatography and mass spectrometry as 3,4-dimethoxyacetophenone (12) and dimethoxybutylbenzene. Compounds with similar structures were compared with the natural germination inhibitors with regard to their bioactivity.
Hydroxylation of the B-Ring of Flavonoids in the 3′-and 5′-Position with Enzyme Extracts from Flowers of Verbena hybrida
Authors: Stotz G. , Forkmann G.
Published: August 2018

Enzyme preparations from flowers of Verbena hybrida do not only catalyse hydroxylation of the B-ring of flavanones and dihydroflavonols in the 3'-position but also in the 5'-position. Enzyme activity for 3',5'-hydroxylation was found to be localized in the microsomal fraction and required NADPH as cofactor. Evidence is provided that the formation of the 3',4',5'- hydroxylated flavanone (5,7,3',4',5'-pentahydroxyflavanone) and dihydroflavonol (dihydromy- ricetin), respectively, proceeds via the corresponding 3',4'-hydroxylated compounds eriodictyol and dihydroquercetin, respectively, which are most probably formed by action of the same enzyme. Enzyme activity for 3',5'-hydroxylation was found to be strictly correlated with the prescence of 3',4',5'-hydroxylated flavonoid compounds in the flowers.
On the Role of Hydrogen Peroxide in Peroxidase Catalyzed Metabolism of Indole-3-acetic Acid
Authors: Grambow Hans J.
Published: August 2018

Formation of H2O2 in the course of peroxidase catalyzed IAA metabolism was measured using the peroxide-dependent decarboxylation of [14C]glyoxylate and the oxidation of phenolic substrates giving rise to fluorescent products in IAA/HRP systems. The results agree with the recent concept of IAA metabolism which includes the formation of H2O2 in the course of oxidase action on IAA and the consumption of this H2O2 by subsequent peroxidase action in the presence of phenolic cosubstrates.
Polycation-Bacterium Interactions and Wall Subunits as Endocytosis Factors. Topoisomeraselike Action of Basic Polypeptides Suggesting a 7th Class of Enzymes: The Stereases
Authors: Antohi Stefan
Published: August 2018

Lysine rich histone and polylysine are bacteriolytic for Bacillus subtilis and Escherichia coli cells, whereas histones H2A, H2B and H3, assayed separately are not. Polyarginine bacteriolysis of E. coli with polycation 10 μg/ml decreased with higher concentrations, the killed nonlysed cells exhibiting wall alterations. All bacteriolytic polycations were lytically effective under reciprocal shaking, but not under magnetic stirring conditions, demonstrating the requirement for cell lysis of mechanical fields developed in oscillatory movements. Scanning electron microscopy of histone H1 treated B. subtilis cells showed the formation of globular bodies (polionosomes) in the cell surface. The interference of Ca2+ and 0 °C exposure with the polycation action observed especially in E. coli, the polionosomes, and the dynamics in polycationic cell lysis, considered together, suggest the existence o f wall supramolecular subunits (murameres), defined by their ability to form polionosomes. The murameres undergoing reversible conformational transitions induced by ectobiological signals, e.g., Ca2+, would make up an uptake system. The involvement of this system in environmental interactions and DNA uptaking, as well as the general stereo-enzyme like nature o f the conformational changes caused by polycations are discussed.
Thermodynamic Approach to a Possible Theory of the Evolution of a Genetic Code
Authors: Macchiato M. F. , Tramontano A.
Published: August 2018

One of the distinctive features of a biological system is its remoteness from equilibrium: for the treatment of the information exchanged by these systems with the external world the concept of information amount is not sufficient because for nonequilibrium systems we need further specifications about information, i. e. its value.

We defined the information value for a genetic code. The comparison of the results we had applying such a definition to the three genetic codes found in nature shows that our definition described the system of transmission and reception of information in a biological organism very well and that the information value of a genetic code can be considered as an index of its efficiency, i.e. of its ability to minimize the effects of a mutation of the genotype on the phenotype.

Otherwise, our results show that the information value, and hence the efficiency of the three known codes is the same and suggest that the prerequisite of the evolution of the codes is the preservation of this value.
Naramycin B, an Antibiotic from Streptomyces griseus Strain 587 with Herbicidal Properties-Fermentation, Isolation, and Identification
Authors: Berg Dieter , Schedel Michael , Schmidt Robert R. , Ditgens Klaus , Weyland Horst
Published: August 2018

From the culture filtrate of Streptomyces griseus strain 587 a herbicidal active fraction was isolated by adsorption on Lewapol® , methanolic desorption, and chromatography on Sephadex® LH-20. Further purification was achieved by HPLC. The pure product was characterized by TLC and different colour reactions. By MS, 1H-NM R, IR and ORD spectroscopy the herbicidal compound could be identified as naramycin B. Naramycin B is an optical isomer of cycloheximide (naramycin A, Actidione®, Acti-Aid®). This communication reports on the fermentative production of naramycin B with strain 587, its isolation, identification, and herbicidal activity.
Localization of Ca2+ at the Plasma Membrane of Bullfrog Myocardial Cells
Authors: Meyer R. , Schmitz M. , Stockem W. , Haas H. G.
Published: August 2018

Cellular distribution and localization of Ca2+ in bullfrog myocardial cells was investigated on the light and electron microscopical level using different preparation procedures. Fixation and dehydration in glutaraldehyde and ethanol solutions containing increased amounts of Ca2+ (5-25 mᴍ) cause the formation of numerous electron-dense deposits at the external face of the sarcolemma. X-ray microanalysis demonstrates that the deposits are mainly composed of calcium. Similar results were obtained in cryopreparations by quick-freezing of fresh myocardial tissue. Granules with a diameter of 16.6 nm, which clearly exceed all other cell constituents in contrast, are found at the entire myocardial cell surface. Besides an increased amount of calcium the granules contain potassium and phosphorus. Fluorescence microscopy on single cells obtained from bullfrog atrium by treatment with digestive enzymes and stained with chlorotetra-cycline (CTC) as a fluorescent probe for membrane-bound Ca2+ clearly support the observations made on the fine structural level. A strong fluorescence signal depending on the CTC-and Ca2+-concentration of the incubation medium is observed at the sarcolemma and can be inhibited by addition of La3+.

The results of the present investigation suggest that the surface coat of the sarcolemma of myocardial cells represents an important compartment for accumulation and release of external Ca2+. The external lamina which partly covers the surface of myocardial cells seems not to be involved in the Ca2+ exchange.
Induktion von Einzel-und Doppelstrangbrüchen in linearer und superzirkularer DNA durch Phleomycin / Induction of Single-and Double-Strand Breaks in Linear and Superhelical DNA by Phleomycin
Authors: Schmülling Franz , Köhnlein Wolfgang
Published: August 2018

Phleomycin induced DNA breakage was investigated with superhelical Col. E1 DNA and linear T2 DNA as well. In both DNA-forms besides single-strand breaks direct double-strand breaks were produced by the drug. The double-strand breakage rate obtained after treatment with phleomycin, however, was considerably smaller than that found after bleomycin treatment. Whereas the single-and double-strand breakage rate in Col. E1 DNA showed a linear and nearly quadratic dependence on the phleomycin concentration, respectively, in T2 DNA the breakage rates increased faster than the first or second power of the concentration. This indicates various modes of drug-DNA interaction. Under nondegrading conditions a strong retardation of electrophoretic mobility was observed for all three topological isomers of Col. E1 DNA whereas the sedimentation behaviour remained unchanged.

The in vitro effects (strand breakage) of phleomycin and bleomycin are compared with in­ duction of chromosomal aberrations in human lymphocytes and oocytes of Drosophila melanogaster.
Effect of Water Soluble Polymer, Polyethyleneglycol, and Glass-Forming Compounds on Cell Fusion
Authors: Yoshii Fumio , Kaetsu Isao
Published: August 2018

The cell fusion of Molt T-cells was investigated in the presence of water soluble polymer, polyethyleneglycol (PEG) and glass-forming monomers. In cell fusion with PEG only, inactivation of the cell occurred within 2 min. However, in the presence of PEG and water soluble polymer, most of the fused and unfused cells lived even after fusion times of more than 10 min. It was observed that water soluble polymer prevented the inactivation of cells during fusion as a protectant. As the result, ratio of fused cells increased in the presence of water soluble polymers.

Some glass-forming monomers used as new fusogens such as M-23G (n = 23) and M-50G (n = 50) monomers having long oxyethylene chains in the methoxypolyethyleneglycol methacrylate, CH3O-(-CH2CH2-O)n-CO-C(CH3)=CH2 as well as PEG #2000 indicated large promoting and protecting effects on cell fusion.
Inactivation of the Sarcoplasmic Reticulum Calcium -Transport-ATPase by Lasolocid in Combination with Triton X-100
Authors: Hasselbach Wilhelm , Lüdi Hans , Migala Andrea
Published: August 2018

The calcium-transport-ATPase of the sarcoplasmic reti­culum membranes is irreversibly inactivated by the combined action of Lasolocid and Triton X-100 at concentrations which separately do not interfere with the enzyme's activity. In the presence of Lasolocid the enzyme is most susceptable to inactivation when the Triton X-100 concentration just exceeds its critical micellar concentration, ~ 0.2 mg · ml-1. Lasolocid becomes effective at a concentration of 10 μᴍ and produces rapid inactivation at 100 μᴍ . The enzyme is more rapidly inactivated in the active than in the inactive state.
Structure Elucidation of Pterosupin from Pterocarpus marsupium, the First Naturally Occurring C-Glycosyl-β-hydroxy-dihydrochalcone
Authors: Adinarayana Dama , Syamasundar Kodakandla Venkata , Seligmann Otto , Wagner Hildebert
Published: August 2018

The chemical examination of Pterocarpusm arsupium root afforded pterosupin, a new C-glu-cosyl-β-hydroxydihydrochalcone along with pseudobaptigenin, liquiritigenin, isoliquiritigenin, garbanzol, 5-deoxy-kaempferol and p-hydroxybenzaldehyde.
Rubins and Rubinoid Addition Products from Phycocyanin
Authors: Küfer W. , Scheer H.
Published: August 2018

The verdin-type Chromophore of denatured C-phycocyanin (1) from Spirulina platensis is reduced to the corresponding rubin (2a) by sodium borohydride. The structure assigned is in agreement with the uv-vis spectroscopic properties of the product and was deduced from model studies with free bile pigments.

Analogous model studies using sodium dithionite demonstrated a two-fold reactivity for this reagent, leading to products which are both o f the rubin spectral type under the conditions tested. True rubins (10,22-dihydrobilindions) are formed in low yield only if an excess of reagent is used in methanol/water mixtures. It is accompanied by polar addition product(s) of the same spectral type, which are generally formed exclusively. In particular, no bilirubin was formed under the reaction conditions previously applied for the chemical modification of phycobiliproteins and phytochrome. From this finding and from the strikingly different properties of the borohydride and dithionite products, of phycocyanin upon renaturation, the dithionite product is suggested to be a rubinoid addition product (2b) rather than a hydrogenation product.

In contrast to the dithionite addition product 2b of phycocyanin, the chromophore of the true phycorubin (2a) remains stable upon renaturation. The uv-vis spectral properties of the chromophore are not markedly different whether the apoprotein is in its native or denatured state. The different electrophoretic mobilities of native (renatured) phycocyanin compared to the renatured borohydride product suggest that these two have different protein conformations.

The preparation of these phycorubins renders the extensive techniques of bilirubin chemistry applicable in the study of biliproteins.
The Influence of Detergents on the Ca2+-and Mg2+-Dependent Adenosine Triphosphatase of the Sarcoplasmic Reticulum
Authors: Lüdi Hans , Rauch Bernhard , Hasselbach Wilhelm
Published: August 2018

During the stepwise solubilization of sarcoplasmic reticulum vesicles with detergents, the following changes in the structural and enzymatic properties of the preparation are observed:

1. The viscosity of the vesicular suspension initially rises. This change is accompanied by the formation of elongated tubules. Subsequently the membranes are completely desintegrated, resulting in a considerable reduction of the viscosity.

2. A decrease in the activity of the Ca2+-dependent ATPase, which is restored after complete solubilization.

3. A decrease in the change of intrinsic tryptophan-fluorescence on removal of calcium ions, which is also restored after complete solubilization.

4. A decrease of the calcium affinity of the ATPase.

5. A decrease in the amount of phosphorylated protein formed by the incorporation of inorganic phosphate. On the other hand, the amount of phosphoprotein formed from ATP is not affected during solubilization.

6. The dependence of the initial rates of phosphoprotein formation from inorganic phosphate on either magnesium or inorganic phosphate at low concentrations of the respective ligand changes from an S-shape profile to a normal hyperbolic profile after solubilization.
Periodicities of Dinucleotide Self-Information Values in Φ X174 DNA
Authors: Furlong N. Burr , Beckner C. F.
Published: August 2018

The natural DNA sequence of bacteriophage, ΦX174, when analyzed as a "text" of dinucleo­ tides, is shown to display an easily detectable degree of non-randomness by the distribution of values of dinucleotide self-information along the sequence. Self-information corresponding to occurrences of dinucleotides separated by a single nucleotide is found to be somewhat higher than the values which preceed or follow it for every third nucleotide position along the sequence. Consequently autocorrelation coefficients of these values display a strong periodicity and harmonic analysis of the values shows a spike at a value of 3. Self-information autocorrelation periodicity is used as a test of the effect of randomizing portions of the sequence. Any one or two of the three nucleotides in each triplet of the sequence can be chosen at random without losing dinucleotide self-information periodicity except when both the 1st and 3rd nucleotide of all of the triplets in the major ΦX174 protein reading frame are randomized. Periodicity is also lost when sequences are generated by randomizing triplets.

Autocorrelation and harmonic analysis also indicate other less marked periodic features of dinucleotide self-information values of the native sequence; non-random features are suggested at periods of 12,20 and 24 nucleotides.
3-O-methyl, 8-C-methyl-quercetin, ein neues Flavonoid-Aglykon aus Dasylirion acrotrichum und Xanthorrhoea hastilis (Liliales) / 3-O-Methyl, 8-C-Methyl Quercetin, a New Flavonoid from Dasylirion acrotrichum and Xanthorrhoea hastilis (Liliales)
Authors: Laracine Claire , Favre-Bonvin Jean , Lebreton Philippe
Published: August 2018

A novel C-methylated flavonoid has been isolated from the leaves of Dasylirion acrotrichum and Xanthorrhoea hastilis. It was identified by spectroscopic methods as 3-Omethyl, 8-C-methyl quercetin. The taxonomic and ecophysiological implications are discussed.
Die Bedeutung der Verknüpfungsposition des Adenosins im NAD+ für die Coenzymaktivität gegenüber Lactatdehydrogenase / The Importance of the Position of the Adenosine Linkage in NAD+ for Its Coenzyme Activity via Lactate Dehydrogenase
Authors: Schlimme Eckhard , Mattem Roland , Schott Eberhard
Published: August 2018

We report on the chemical preparation of the NAD+ analog P1, P2-(5′-β-nicotinamideribofuranosyl-3″-adeno-syl)-diphosphate (N3″AD+) by applying the 1,1′-carbonyl-diimidazole activation method. The importance of how adenosine is linked to the nicotinamide mononucleotide phosphoriboride (NMNPR+) moiety is discussed with re­ spect to the coenzyme activity in the lactate dehydrogenase catalyzed reaction.
Proton NMR-Relaxation Dispersion in Meconium Solutions and Healthy Amniotic Fluid: Possible Applications to Medical Diagnosis
Authors: Béné Georges J. , Borcard Bernard , Graf Volker , Hiltbrand Emile , Magnin Patric , Noack Friedrich
Published: August 2018

In order to show that for a possible application in medical diagnosis NMR-relaxation experiments at low Larmor frequencies (v0 ≤ 20 kHz) are more sensitive than the up to now done high field measurements in the MHz-range, we present dispersion curves (v0 = 50 Hz to 50 MHz) of the proton longitudinal relaxation time T1 and values of the transversal relaxation time T2 for the example of amniotic fluids. Only for Larmor frequencies below ≃ 100 kHz the relaxation times for healthy amniotic fluid and pathological meconium solutions are significantly different, whereas at high Larmor frequencies, i. e. in the conventional MHz-range, the observed changes are rather small.
Adaptation of Chloroplast-Ultrastructure and of Chlorophyll- Protein Levels to High-Light and Low-Light Growth Conditions
Authors: Lichtenthaler H. K. , Kuhn G. , Prenzel U. , Buschmann C. , Meier D.
Published: August 2018

Adaptation In saturating light radish seedlings grown in high-light growth conditions (90 W · m-2) possess a much higher photosynthetic capacity on a chlorophyll and leaf area basis than the low-light grown plants (10 W · m-2). The higher CO2-fixation rate of HL-plants is due to the presence of HL-chloroplasts which possess a different ultrastructure and also different levels of the individual chlorophyll-carotenoid-proteins than the LL-chloroplasts of LL-seedlings.

1. Ultrastructure: The high-light adapted chloroplasts are characterized by fewer photo­ synthetic membranes per chloroplast section, by low grana stacks (only few thylakoids per granum), a lower stacking degree of thylakoids, a higher proportion of non-appressed membranes (stroma thylakoids + end grana membranes) and a high starch content. The LL-chloroplasts possess no starch, their grana stacks are higher (up to 17 thylakoids per granum) and also significantly broader than that of HL-chloroplasts.

2. Chlorophyll-proteins: The photosynthetic apparatus of HL-chloroplasts contains a larger proportion of chlorophyll a-proteins of photosystem I (CPIa + CPI) and of photosystem II (CPa, the presumable reaction center of PS II) than the LL-chloroplasts which possess a higher proportion of light-harvesting chlorophyll a/b-proteins (LHCP1, LHCP2, LHCP3, LHCPy). The higher levels of LHCPs in LL-plants are associated with a higher ground fluorescence fo and maximum fluorescence fp of the in vivo chlorophyll.

3. Chlorophyll and carotenoid ratios: The chloroplasts of HL-plants possess a higher proportion of chlorophyll a and β-carotene (higher values for the ratios chlorophyll a /b and lower values for a/c and x/c) which reflect the increased level of the chlorophyll a/β-carotene-proteins CPIa, CPI and CPa. The higher level of light-harvesting chlorophyll a/b-xanthophyll-proteins (LHCPs) in LL-plants is also indicated by an increased content of xanthophylls and chlorophyll b as seen from lower a/b and higher x/c and a/c ratios.

4. The results indicate that plants possess the capacity for an ontogenetic adaptation of their photosynthetic apparatus to the incident light intensity. The HL-chloroplasts of HL-plants which contain less antenna chlorophyll, are adapted for a more efficient photosynthetic quantum conversion at light saturation than the LL-chloroplasts with high grana stacks. The correlation between higher levels of light-harvesting chlorophyll a/b-proteins (LHCPs) and a higher stacking degree of thylakoids, and the involvement of LHCPs in stacking is discussed.
Phosphorylation of Ca2+-ATPase by Inorganic Phosphate in Water-Organic Solvent Media: Dielectric Constant and Solvent Hydrophobicity Contribution
Authors: Otero Angela de Souza , Meis Leopoldo de
Published: August 2018

The effect of organic solvents on the phosphorylation of the Ca2+-dependent ATPase of sarcoplasmic reticulum by inorganic phosphate in the absence of a calcium gradient was investigated. Kinetic analysis of the reaction in water and water-organic solvent media according to a bireactant scheme shows no correlation between changes in kinetic parameters and the dieletric constant of the mixed solvents. The pronounced increase in equilibrium levels of phosphoenzyme in water-solvent mixtures is attributed to changes in the water activity of the medium.
Notizen: Hyperglycemia in the Fresh Water Field Crab (Oziotelphusa senex senex) Produced by a Pesticide (BHC)
Authors: Reddy P. Sreenivasula , Babu S. B. Ramesh , Ramamurthi R.
Published: August 2018

Hyperglycemia, Oziotelphusa senex senex, Hyperglycemic Hormone, Hexachlorocyclohexane (BHC) Benzene hexachloride (1,2,3,4,5,6-hexachlorocyclohe-xane) (BHC) produced a significant increase in the hemolymph sugar level of intact crabs. Oziotelphusa senex senex, apparantly by triggering release of the hypergly­ cemic hormone (HGH).
Notizen: A New Method to Prepare Membrane Fractions Containing Ionophore-Stimulated ATPase from Pumpkin Hypocotyls (Cucurbita maxima, L .)
Authors: Scherer Günther F. E.
Published: August 2018

In membrane fractions from pumpkin hypocotyls AT­Pase activity was stimulated by a combination of CCCP (carbonyl cyanide m-chlorophenylhydrazone), a protonophore, and valinomycin, a K+-ionophore. Singly, these ionophores stimulated ATPase activity much less. Nigericin, an H+/K+-antiporter, and nystatin, a cation pore, had similar effects as the combination of CCCP and valinomycin. The results suggest the presence of a cation-translocating ATPase which is stimulated by ionophores by dissipating cation gradients formed in the vesicles. A major part of the ionophore-stimulated ATPase activity correlated with marker enzymes for plasma membranes but part of it could be located in other compartments.
DEAE-Dextran Induced Increase of Membrane Permeability and Inhibition of Photosynthesis in Dunaliella parva
Authors: Gimmler H. , Lotter G.
Published: August 2018

As a prerequisite for studies of the intracellular distribution of enzym es of the glycerol cycle in Dunaliella parva, the effect of the polycation DEAE-dextran on the permeability of membranes for various endogenous compounds and on photosynthesis was investigated.

DEAE-dextran induces an increase of the permeability of membranes for low and high molecu­lar weight compounds: Under the influence of DEAE-dextran low molecular com pounds of the cells diffuse more rapidly along the chemical concentration gradient into the medium than macro-molecules. Furthermore enzymes of the cytoplasm do occur more rapidly in the outer medium than enzymes of the chloroplasts.

Photosynthetic CO2 fixation is inhibited already at low DEAE-dextran concentrations. This in­ direct inhibition is due to an unspecific efflux of compounds of low molecular weight, such as inorganic cations, metabolites or nucleotides. At high DEAE-dextran concentrations photo­ synthetic electron transport is directly affected at the level of the thylakoids: Electron transport is inhibited between plastoquinone and photosystem I.

The efflux characteristics of marker enzymes of DEAE-dextran treated D. parva cells show that under optimal experimental conditions this technique may be a suitable tool to get information about the intracellular distribution of enzym es of unknown localization in the alga.
New Flavonol Acetates from the Frond Exudate of the Fern Notholaena aschenborniana
Authors: Jay Maurice , Viricel Marie-Rose , Favre-Bonvin Jean , Voirin Bernard , Wollenweber Eckhard
Published: August 2018

The farinose frond exudate of the fern Notholaena aschenborniana was previously shown to contain a mono­ acetate and a mono-butyrate of a 8-hydroxyflavonol as major constituents and the same pair of esters of a second 8-hydroxyflavonol as minor components. Now we have been able to identify the 8-acetates of two further flavonols. The structures of 5-hydroxy-3,7,2′,3′,4′-pentamethoxy-8-acetoxyflavone and 5,4′-dihydroxy-3,7,3′-trimethoxy-8-acetoxyflavone have been elucidated by spectroscopic methods. Both are novel natural products.
Synthesis of 2′-/3′-O-Acylated Adenine Nucleotide Analogs and Their Interactions in Photophosphorylation
Authors: Onur G. , Schäfer G. , Strotmann H.
Published: August 2018

By mono esterification of 3′(2′)-hydroxyl residues of adenine nucleotides with various carboxylic acids a series of nucleotide analogs is available including fluorescent and photoaffinity labels. Their chemical synthesis is described. The equilibrium between 2′ and 3′ esters is determined by NMR spectroscopy, stability of the esters and their tendency of acyl migration is discussed.

The interaction of the ADP derivatives with the chloroplast ATP synthesizing system is investigated. Actually, the analogs are typical energy transfer inhibitors, strongly inhibiting photophosphorylation and concomitant coupled electron transport (ci50 values ranging from 0.3 to 85 hm). On the basis of inhibitory activities of analogs bearing varying 3′-(2′)-substituents, structure-activity relationships are discussed.

The inhibitory properties of the employed ADP analogs are based on their specific interaction with the catalytic ADP binding site of CF, and their extremely slow phosphorylation on the enzyme (rate 0.25% or less compared to ADP phosphorylation). Inhibition is competitive to ADP but non-competitive with regard to Pi. It is specific for the ADP derivatives, whereas the corresponding ATP analogs are only weak inhibitors in phosphorylation and the AMP derivatives are completely inactive. In light-triggered ATP hydrolysis, however, the ATP analogs exhibit an even stronger competitive inhibition than the ADP derivatives. The results suggest that a conformational change of ATPase takes place when the chloroplasts are transferred from energized to de-energized conditions which greatly affects the properties of the active site with respect to nucleotide binding.
Sensitive Fluorimetric Assay for Adenosine Deaminase with Formycin as Substrate; and Substrate and Inhibitor Properties of some Pyrazolopyrimidine and Related Analogues
Authors: Wierzchowski Jacek , Shugar David
Published: August 2018

The nucleoside antibiotic formycin, 7-amino-3-(β-ᴅ-ribofuranosyl)pyrazolo(4,3-d)pyrimidine, a structural analogue of adenosine, is deaminated about 10-fold faster by adenosine deaminase than adenosine itself, and is therefore a superior substrate for both routine assays and kinetic studies with the purified enzyme. The luminescence properties of formycin have been profited from to develop a fluorimetric assay for adenosine deaminase which is considerably more sensitive than the spectrophotometric procedure widely employed with adenosine as substrate. Examples are presented of its application to routine assays of adenosine deaminase levels in cellular extracts, as well as to kinetic studies with the purified enzyme, including the properties of some pyrazolopyrimidine and purine substrates and inhibitors.
Time-Resolved Fluorescence Studies of Hematoporphyrin in Different Solvent Systems
Authors: Andreoni A. , Cubeddu R. , De Silvestri S. , Jori G. , Laporta P. , Reddi E.
Published: August 2018

Time-resolved fluorescence studies of hematoporphyrin in aqueous solution and in different organic solvents are presented. The| observation of two exponential components in the fluorescence decay in aqueous solution reveals the presence of a monomeric and aggregated (probably dimeric) form of the molecule, as confirmed by absorption and fluorescence measurements. The slow component (~ 15 ns in aqueous solution) and the fast one (~ 3.8 ns in aqueous solution) are attributed to monomers and dimers, respectively. Higher aggregated species of hematoporphyrin are also present, which are essentially devoid of fluorescence properties.
Isolation and Identification of Isoflavanone Phytoalexins from Leaflets of Diphysa robinioides
Authors: Ingham John L. , Tahara Satoshi , Tahara Satoshi
Published: August 2018

A major phytoalexin produced by the fungus-inoculated leaflets of Diphysa robinioides has been identified as the new isoflavonoid 5,7,2′,4′-tetrahydroxy-6-(3,3-dimethylallyl)isoflavanone (diphysolone). It is accompanied by smaller quantities of diphysolone-4′ (or 2′)-O-methyl ether (diphysolidone), and the known isoflavonoids 5,7,2′4′-tetrahydroxy-8-(3,3-dimethylallyljiso- flavanone (kievitone) and 5,7,2′-trihydroxy-4′-methoxyisoflavanone (ferreirin)