bluuebunny/crossref_metadata_2025 huggingface dataset:
Natural Inhibitors of Germination and Growth, III New α-Pyrones from Seeds of Rosa canina
Authors: Lohaus Edith , Zenger Claudia , Rüdiger Wolfhart , Cmiel Edmund
Published: August 2018

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

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

Similar density values of q = 1.39- 1.46 g/cm3 and similar repeating periodicities were deter­ mined for murein and pseudomurein. Periodicities of 4.5 and 9.5 Å were measured in the planes of the sacculi of both cell wall polymers. Vertical to these planes periodicities of 42 to 45 A were obtained.

These data may be interpreted as functions of an oblique-angled elementary cell with an area of about 4.5 Å × 10 Å and a height of 21 to 22.5 Å. This elementary cell includes one disac-charidepeptide subunit. As a consequence of this lattice periodicities the glycan strands of murein and pseudomurein perform twofold screw axes. Therefore the peptide chains, linked at distances of about 10 Å to every second sugar residue, point in identical directions. The parallel array of the polysaccharide chains associated with periodicities of 4.5 Å causes, therefore, a separation of the carbohydrate and peptide moieties of murein and pseudomurein. The head-to-head or tail-to-tail packing of such layers provides periodicities of 42-45 Å.

Because of the twofold screw axis of the glycan strands, the secondary structure of the polysac­ charide strands of murein resembles the secondary structure of chitin.

Since all glucosidic oxygen atoms occupy equatorial positions, if the β-1,3 linked N-acetyl-D-glucosamine residues are in the 4C1, conformation and the β-1,3 linked N-acetyl-L-talosaminuronic acid residues in the 1C4 conformation, the polysaccharide chains of pseudomurein may also perform a twofold screw axis.
Fast Atom Bombardment Mass Spectrometry of Coumaric Acids
Authors: Koster Chris G. de , Niemann Gerard J. , Heerma Wigger
Published: August 2018

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

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

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

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

Changes in oxygen evolution or uptake in illuminated plastids were studied during the early stages of greening in etiolated leaves. An oxygen uptake was observed in etioplasts, which persisted even after the appearance of oxygen evolution. This oxygen uptake was most pronounced in etioplasts or in plastids prepared after redarkening the plants. Incubation of pre-illuminated etioplasts in the presence of NADPH resulted in an inhibition of the uptake in a subsequent illumination. Addition of NADPH had three further consequences: a shift of the chlorophyllide absorbance band to 682 nm, an inhibition of pigment photodestruction and the appearance of a light-induced fluorescence transient at room temperature. Inhibition of pigment photodestruction by NADPH was maximal when the experimental conditions favoured the formation of the P682 chlorophyllide-protein.

It is inferred that the oxygen uptake seen under these conditions is due to pigment photooxidation. Inhibition of both phenomena by NADPH is ascribed to the specific interaction of the nucleotide with the pigment-protein complexes and to the ability of these complexes to undergo the light-induced chlorophyllide microcycle, described by Franck and Inoue (Photobiochem. Photobiophys. 8, 85-96, 1984). In the leaf, NADPH is thought to play the same role.
A Fungal Elicitor of the Resistance Response in Wheat
Authors: Kogel Karl-Heinz , Heck Birgit , Kogel Gerd , Moerschbacher Bruno , Reisener Hans-Joachim
Published: August 2018

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

The range of inorganic acid normalities for maximum color formation of the phosphomolybdenum- blue complex (under heating) increases by elevating the ammonium molybdate concentration, and at a ratio of molybdate molarity/acid normality equal to 10, there is maximum color development at any acid normality in the range 1-4 ɴ with either HClO4 or H2SO4 (or their mixtures).

On the basis of these features a revised method is described for the accurate determination of phosphonate-P percent of total-P. on lipid extracts and on TLC bands. The color at the final step, in both cases, is developed under the same conditions of molybdate, HClO4 and H2SO4 concentrations, thus avoiding possible errors produced by the use of two separate calibration curves.
Some Remarks About Laser-Induced Mass Spectrometry of Bacteria
Authors: Albrecht J. , Schmid E. W. , Süssmuth R.
Published: August 2018

In order to investigate the availability of laser-induced mass spectrometry for the determination of bacteria, ten strains of the genera Escherichia and Streptococcus were chosen. Gram-negative as well as Gram -positive lysogenic and non-lysogenic. pathogenic and non-pathogenic strains were examined. Giant pulses of a Nd: YAG laser (frequency quadrupled, wave-length 265 nm) were used to vaporize and partly ionize the bacterial material. The time-of-flight mass spectra obtained could be discriminated by using the stepwise discriminant analysis provided by BM DP software package. Two different methods relating centrifugation and washing procedures were used. With the first method a correct classification between 50.0 and 90.9 per cent (S. sanguis) by means of mass spectra of positive ions and a correct classification between 27.1 and 80.4 per cent (S. lactis-25) by means of mass spectra of negative ions was observed. Using the second method a correct classification between 40.7 and 93.3 per cent (5. lactis-25) by means of mass spectra of positive ions and a correct classification between 56.7 and 95.0 per cent by means of mass spectra of negative ions was obtained. Here 5. sanguis with 93.3 and S. lactis-25 with 81.7 per cent were significantly differentiated. In this context it must be em phasized that a correct classification of 27 per cent must be considered statistically significant, if 10 different strains are used.
Notizen: Neue Pulvinsäurederivate aus Pulveroboletus- Arten (Boletales)/ New Pulvinic Acid Derivatives from Pulveroboletus Species (Boletales)
Authors: Marumoto Ryuji , Kilpert Claus , Steglich Wolfgang
Published: August 2018

Vulpinic acid has been isolated from sporophores of Pulveroboletus ravenelii, its first reported occurrence in a Basidiomycete. Permethyl ethers of methyl xerocomate and methyl atromentate and its corresponding monochloro derivatives are produced by P. auriflammeus of Japanese origin.
Major Indole Alkaloids Produced in Cell Suspension Cultures of Rhazya strict a Decaisne
Authors: Pawelka Karl-Heinz , Stöckigt Joachim
Published: August 2018

Eleven main alkaloids were identified from cell suspension cultures of Rhazya stricta grown in 4X-medium for 15 days. The alkaloids comprised the five groups Corynanthe, Strychnos, Eburnan, Secodine, and Aspidosperma and can be regarded as being typical Rhazya alkaloids, although the Strychnos alkaloid akuammicine has been isolated for the first time from the genus Rhazya. The most abundant compound was ( + )-1,2-dehydroaspidospermidine (15 mg/l medium) whereas all other constituents were synthesized in about 5 - 10 times lower amounts. More than 15 further alkaloids were formed as minor components which have not yet been identified. Cultivated Rhazya cells have been shown to be one of the richest alkaloid sources from apocynaceous cell suspensions.

The isolated compounds, because of their structural heterogeneity, cannot be presently arranged into a scheme with coherent biosynthetic sequences.
Determination of Hyoscyamine and Scopolamine in Datura innoxia Plants by High Performance Liquid Chromatography
Authors: Plank Karin-Heide , Wagner Karl G.
Published: August 2018

For the determination of the hyoscyamine-scopolamine content in small quantities of fresh plant tissue an HP LC assay was developed; with a sensitivity of about 20 ng alkaloid per run. Analysis of the different organs of Datura innoxia plants are in accord with the concept that hyoscyamine is synthesized in the roots, whereas transformation to scopolamine starts in these organs and proceeds in the aerial parts of the plant.
Impact of UV-B Radiation on Photosynthetic Assimilation of 14C-Bicarbonate and Inorganic 15N-Compounds by Cyanobacteria
Authors: Döhler Günter , Biermann Irene , Zink Joachim
Published: August 2018

The cyanobacteria Anabaena cylindrica and Synechococcus leopoliensis (= Anacystis nidulans) were grown at different levels of UV-B radiation (439. 717, 1230 and 1405 J m -2d-1 weighted according Caldwell, 1971) for 2 days. Dry weight was hardly affected but phycocyanin content of both species decreased linearly to the level of UV-B radiation. Contents of protein, carotenoids and chlorophyll a were reduced only after exposure to high doses (1230 J m-2d-1) of UV-B radiation. Photosynthetic 14CO2 fixation of Anabaena cells was reduced linearly with increasing UV-B dose whereas no effect could be observed in Synechococcus. A depression of photosyn­thetic 15N-nitrate uptake was found after UV-B stress in both species. UV-B irradiance caused an increase of 15N-incorporation into glutamine, but no effect was noted for incorporation into alanine or aspartic acid. An increase of 15N-excess in glutamic acid linear with the UV-B dose was observed in Synechococcus, only. Patterns of 14C-labelled photosynthetic products were either less affected by UV-B radiation (Anabaena) or an enhancement of 14C-label in total amino acids was detected (Synechococcus). The amount of total free amino acids increased parallel to the level of UV-B radiation. Only, the high dose of UV-B (1405 J m-2d-1, weighted) results in a decrease of the glutamine pool. Our results indicate an inhibition of glutamate synthase by UV-B irradia­tion in Anabaena, only. Results were discussed with reference to the damage of the photosyn­thetic apparatus.
The Dynamics of Bone Mineral in Some Vertebrates
Authors: Driessens F. C. M. , Verbeeck R. M. H.
Published: August 2018

In the literature octocalcium phosphate as well as brushite have been proposed as the precursor phase for bone mineral in the higher vertebrates. In this study it is shown that the situation is more complex. A sodium and carbonate containing apatite (NCCA) and a magnesium whitlockite (MWH) are present from the beginning of mineralization together with octocalcium phosphate. Upon further bone development the NCCA and the MWH phase are deposited in amounts proportional to the amount of mineral deposited. However, the octocalcium phosphate is transformed slowly in a heavily carbonated defective hydroxyapatite. From the available experimental data it can be derived that the time of this transformation is smaller than four weeks under in vivo conditions.
The Macromolecular Structure of Collagen in Tendon Fibres of Dermatosparactic Animals
Authors: Mosler E. , Folkhard W. , Geercken W. , Helle O. , Knorzer E. , Koch M. H. J. , Nemetschek-Gansler H. , Nusgens B. , Nusgens B. , Lapière Ch. M.
Published: August 2018

Small-angle x-ray diffraction spectra of dermatosparactic tendon collagen show a decreased intensity of the first order reflection. We interprete this finding to be due to the N-terminal propeptide which fills the intermolecular gap region partially.
Identification of (R)-Vicianin in Davallia trichomanoides Blume
Authors: Lizotte Pauline A. , Poulton Jonathan E.
Published: August 2018

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

Feeding experiments using 13C-labelled sodium acetate precursors in CuCl2-treated broad bean (Vicia faba) cotyledons have demonstrated that the furanoacetylene phytoalexin wyerone is biosynthetically derived from seven intact acetate units. A further experiment using sodium [2H3]acetate indicated the head of the chain, and showed the chain is analogous to that of a fatty acid precursor, any chain shortening process from postulated C18 precursors occurring from the carboxyl end. Incorporations of oleate and linoleate were, however, regarded as insufficient to prove the involvement of these compounds in the biosynthetic pathway.
Host-Pathogen Interactions XXX. Characterization of Elicitors of Phytoalexin Accumulation in Soybean Released from Soybean Cell Walls by Endopolygalacturonic Acid Lyase
Authors: Davis Keith R. , Darvill Alan G. , Albersheim Peter , Dell Anne
Published: August 2018

Endopolygalacturonic acid lyase, purified from the phytopathogenic bacterium, Erwinia carotovora, induces phytoalexin accumulation in soybean (Glycine max L.) cotyledons. This pectin-degrading enzyme releases heat-stable elicitors of phytoalexin accumulation from soybean cell walls, citrus pectin, and citrus sodium polypectate. The most elicitor-active molecules ob­tained by treating soybean cell walls with endopolygalacturonic acid lyase have been purified and characterized. The cell-wall-derived elicitors are α-1,4-linked oligogalacturonides with degrees of polymerization of eight to twelve residues. The molecules with the highest specific elicitor activity were identified as α-1,4 -linked deca- and undecagalacturonides that contained 4,5-unsaturated galactosyluronic acid at the nonreducing termini.
Degradation of NAD(H) by Endogenous Enzymes of Yeasts and Clostridia
Authors: Schuetz Hans-Jürgen , Simon Helmut
Published: August 2018

The time courses of degradation of exogenous NAD and NADH (2.5 mᴍ) catalyzed by endogenous enzymes present in Saccharomyces cerevisiae, Candida utilis, Clostridium spec. La 1, Clostridium kluyveri, and Clostridium sporogenes have been determined. The half lives of the pyridine nucleotides depend extremely on the organism and, for the same organism, on the growth conditions. C. spec. La 1 as well as C. kluyveri possess only negligible enzyme activities for NAD degradation. However, C. sporogenes shows activities leading to half lives of less than 2 h for NAD and 5 h for NADH. At 25 °C half lives in the order of 5-17 h have been observed for Candida utilis under different conditions. The half lives of NAD are roughly 5 times higher in the presence of Saccharom yces cerevisiae.
Composition of Lipopolysaccharides from Various Strains of Rhodomicrobium vannielii
Authors: Holst Otto , Weckesser Jürgen , Rieth Baldur , Dow Crawford S.
Published: August 2018

The compositions of lipopolysaccharides from the photoheterotrophic budding Rhodomi­crobium vannielii strains DSM 162, Rm5, E3 and 2/1 are reported. Common constituents of these lipopolysaccharides are glucose, mannose, glucosamine, glucuronic and galacturonic acids, 2-keto-3-deoxyoctonate (KDO) and the fatty acids 3-OH-C16:0, 3-OH-C14:0, C14:0, Δ14-C22:1, aside from strain specific differences.

Two different, medium-dependent growth forms of strain DSM 162 are described. The vitamin/ yeast extract-concentration in the medium and/or the growth temperature were found as factors triggering the different growth forms. Lipopolysaccharides of the two growth forms had only quantitative differences in composition. Lipopolysaccharide from swarmer cells of strain Rm5 showed a chemical composition comparable to that of chain cells and from simple cycle cells of the same strain.
Further Studies on the Biosynthesis of Granaticin
Authors: He Xian-guo , Chang Chiu-Chin , Chang Ching-jer , Vederas John C. , M clnnes A. Gavin , Walter John A. , Floss Heinz G.
Published: August 2018

Experiments with cerulenin-inhibited cultures of 5. violaceoruber showed conversion of dihydrogranaticin (II) into granaticin (I), but not vice versa, confirming an earlier conclusion that II is the biosynthetic precursor of I. Feeding of CH3
13C18O2Na followed by 13C-NMR analysis of the product by the 18O shift method indicated the expected incorporation of 18O at carbons 1,11 and 13 of I and showed that the oxygen of the pyran ring originates from C-3 and not from C-15. Analysis of I biosynthesized from 13C2H3COONa by 13C{1H, 2H} triple resonance NMR spectro­scopy showed the incorporation of one atom of deuterium each at C-2 and C-4. C-16 carried a maximum of 2, not 3, atoms of deuterium. These results are discussed in terms of biosynthetic mechanisms.
The Topology of the Plastoquinone and Herbicide Binding Peptides of Photosystem II in the Thylakoid Membrane
Authors: Trebst Achim
Published: August 2018

The 32 kDa herbicide and QB binding peptide (D-1 protein) and its homologous 34 kDa peptide (D-2 protein) are integral membrane subunits of photosystem II. A model for their folding through the thylakoid membrane in five transmembrane a-helices is proposed from the compari­son of amino acid sequence and hydropathy index plot homologies with subunits of the bacterial system. Following recent data on the X-ray structure of a bacterial photosystem the binding niche for QB is interpreted on the basis of the amino acid changes found in the 32 kDa peptide in herbicide tolerant higher plants and algae.
Rhizomnium magnifolium and R. pseudopunctatum, the First Mosses to Yield Flavone Glucuronides
Authors: Mues Rüdiger , Leidinger Gesine , Lauck Vera , Zinsmeister H. Dietmar , Koponen Timo , Markham Kenneth R.
Published: August 2018

Rhizomnium magnifolium and R. pseudopunctatum show an identical flavonoid pattern with six flavone glucuronides.

Three of them; namely apometzgerin 7-O-glucuronide, selgin 7,5′-di-O-glucuronide and tricetin 7,3′-di-O-glucuronide are new natural compounds. This is the first report of flavonoid glucuronides in mosses.
Isolation and Characterization of 3 Protochlorophyllides from Pigment Mutant C-2 A′ of Scenedesmus obliquus
Authors: Kotzabasis Kiriakos , Senger Horst
Published: August 2018

Three Protrochlorophyllides (protochlorophyllide) were separated from mutant C-2 A′ of the green alga Scenedesmus obliquus. They show distinct differences in polarity, absorption and fluorescence characteristics. Until further characteristics are established we have to assume that we found monovinyl protochlorophyllide (MV-protochlorophyllide), divinyl protochlorophyllide (DV-protochlorophyllide) and a third protochlorophyllide with different side groups. - The question whether these protochlorophyllides are intermediates in the same pathway or precursors of chlorophylls a, b and RC I in separate pathways remains open at this stage of investigation.
Thin Layer Chromatographic and IR Spectral Evidence for the Presence of Phosphonolipids in Human Sperm
Authors: Moschidis Michael C.
Published: August 2018

The total phosphonolipids from human sperm have been isolated by means of preparative TLC and among these the phosphono analogue of phosphatidyl choline has been identified by chromatographic and spectral techniques.
The Glio-Axonal Interaction and the Problem of Regeneration of Axons in the Central Nervous System — Concept and Perspectives
Authors: Wolburg Hartwig , Neuhaus Jochen
Published: August 2018

Lesion of the central nervous system in man is generally believed to be incurable. However, in the last time evidence accumulated that axonal growth occurs after a lesion if the growing neurites encounter a permissive environment. Since astrocytes play a considerable role as environmental factor in the CNS, the astrocytes from regenerative as well as from non-regenerative species were compared. The concept proposed here postulates that interactions between astrocytes and axons are of basic significance for fiber regeneration and have changed qualitatively during phylogeny: in lower vertebrates astrocytes guide growing and regenerating axons; in higher vertebrates including man the glioaxonal interactions were possibly deteriorated by the appearance of new compounds in the astrocytic membrane.
A New Biflavone and Further Flavonoids from the Moss Hylocomium splendens
Authors: Becker Rudolf , Mues Rüdiger , Zinsmeister H. Dietmar , Herzog Friedlinde , Geiger Hans
Published: August 2018

Seven flavonoids were isolated from Hylocomium splendens (Hedw.). B. S. et G. The structures of two of them , the new biflavone 5′,3‴-dihydroxyrobustaflavone, a 5′,6″-C-linked biluteolin. and apigenin 7-O-(2,4-di-O-α-ʟ-rhamnopyranosyl)-β-ᴅ-glucopyranoside were completely elucidated.
Characterization of Glutamine Synthetase of Roots, Etiolated Cotyledons and Green Leaves from Sinapis alba (L.)
Authors: Manderscheid Remigius , Wild Aloysius
Published: August 2018

Glutamine synthetase of roots, etiolated cotyledons and green leaves from mustard plants cannot all clearly be separated by DEAE-Sephacel chromatography. However, the enzyme of the roots, etiolated cotyledons and green leaves, respectively, differed in the kinetic properties deter­mined in the crude extract. The root enzyme showed a pH-optimum of about 6.9, a Km value of 3 mᴍ for glutamate and a temperature optimum at 48 °C. Glutamine synthetase of etiolated cotyledons possessed a Km for glutamate of 6 or 12 mᴍ, depending on the dithioerythritol con­centration in the homogenisation buffer and a temperature optimum at 46 °C. The enzyme of green leaves was characterized by a temperature optimum at 40 °C, a pH-optimum at about 7.4 and a low glutamate affinity with positive cooperative substrate binding. Based on isolation of chloroplasts and identification of glutamine synthetase the enzyme of green leaves seems to be the chloroplastic form. This enzyme was purified by DEAE-Sephacel, hydroxylapatite and Sephacryl S-300 chromatography. Affinity for glutamate and MgSO4 of the purified enzyme differed from that found in the crude extract. The function of the different isoenzymes is discussed.
Are Polyphosphoinositides Involved in Signal Transduction of Elicitor-Induced Phytoalexin Synthesis in Cultured Plant Cells ?
Authors: Strasser Heiner , Hoffmann Christina , Grisebach Hans , Matern Ulrich
Published: August 2018

The phospholipids of cultured parsley and soybean cells were labelled with myo-[2-3H]inositol, [2-3H]glycerol or [32P]orthophosphate. By one-and two-dimensional chromatographic comparison of the labelled phospholipids with reference substances, the presence of 1-(3-sn-phosphatidyl)-ᴅ-myo-inositol 4-phosphate and 1-(3-sn-phosphatidyl)-ᴅ-myo-inositol 4,5-bisphosphate was demonstrated in these cultures. These results were corroborated by analysis of the deacylation products. Cells were labelled with either myo-[2-3H]inositol, [2-3H]glycerol or [32P]orthophosphate and subsequently challenged with elicitor for various lengths of time. Radioactivity in individual phosphoinositides from these cells was determined. No significant influence of elicitor-challenge of either soybean or parsley cells on incorporation of 3H or 32P into polyphospho­inositides was found between 0.5 and 20 min after elicitor addition.
Effect of Tumour Regression on Serum and Tissue Copper Concentration in Mice Bearing Induced Fibrosarcoma
Authors: Chakravarty Prabir Kishore , Ghosh Aparesh , Chowdhury Jaysree Roy
Published: August 2018

Serum and tissue copper concentration was determined in mice bearing induced fibrosarcoma after successful chemotherapeutic treatment. The results showed a significant depression in copper concentration in the serum and tumour tissue after treatment with anti-cancer drugs. However, the liver copper concentration showed no significant change in treated groups of mice compared to before treatment.
Analysis of Single Channel Currents with a Microprocessor Based Device
Authors: Schreibmayer W. , Hofer E. , Wolf P. , Lueger A. , Tritthart H. A.
Published: August 2018

Data evaluation of single channel currents obtained from artificial black lipid membranes and with the patch clamp method is an important part of every single channel study, but it is a time consuming part often exceeding the time for experimentation and recording by far.

We describe here a microprocessor based device, which allows the experimentator to analyse in a simple way the distribution of current levels in a single channel trace (amplitude-histogram analysis of single channel currents) either online, or offline.

Current levels are sampled at a constant frequency of 6 kHz and the relative frequencies of occurrence of these current levels are displayed as a histogram on the screen of an analog or digital storage oscilloscope.

The data reducing algorithm of this analyser eliminates the requirement of large amounts of mass storage that normally is needed for digital amplitude-histogram analysis of single channel recordings.

Examples of evaluation for both a voltage operated cation-channel and a blockage of a potas­sium channel by tetraethylammoniumchloride (TEA) are given.
A Correlation between Detergent Tolerance and Cell Wall Structure in Green Algae
Authors: Biedlingmaier Susanne , Wanner Gerhard , Schmidt Ahlert
Published: August 2018

12 strains of the geni Chlorella, Scenedesmus, Chlamydomonas, and Dunaliella were tested for their tolerance against the anionic detergent “LAS” (linear alkylbenzene sulfonate). Cellular parameters (cell titer and chlorophyll content) were monitored for 28 days after addition of LAS (0.01-2 mᴍ). A 100-fold difference in sensitivity toward LAS was detected for the algal strains analyzed. Electron microscopic investigations revealed that LAS-resistance is correlated with both, the presence of thick cell walls and sporopollenin layers. It is speculated that this structure acts as a protecting coat preventing the chemical attack of detergents on algal cells. An application for selecting algae by detergents is proposed.
Acyclonucleoside Analogues Consisting of 5-and 5,6-Substituted Uracils and Different Acylic Chains: Inhibitory Properties vs Purified E. coli Uridine Phosphorylase
Authors: Drabikowska Alicja K. , Lissowska Lidia , Draminski Marcin , Zgit-Wroblewska Anna , Shugar David
Published: August 2018

Synthetic procedures are described for the preparation of a variety of pyrimidine acyclo- nucleoside analogues, in which the aglycones are 5- and 5,6-substituted uracils, and the ribose moiety is replaced by different acyclic chains. These were examined as potential inhibitors of purified E. coli uridine phosphorylase. None of the compounds was a substrate for uridine phosphorylase, or either a substrate or inhibitor of E. coli thymidine phosphorylase. Kinetic measurements were employed to determine inhibition constants, K1, for inhibition of uridine phosphorylase. One of the more effective of these was 1-(1′3′-dihydroxy-2′-propoxy)methyl-5,6- tetramethyleneuracil, with K1 = 2.7 μᴍ. The same compound was a reasonably good inhibitor of the reverse, synthetic, reaction, with K1 values of 19 μᴍ vs uracil as the variable substrate, and 15 μᴍ νs α-ᴅ-ribose-1-phosphate as the variable substrate. For one of the analogues, which was a racemate, 1-(2′,3′-dihydroxypropyl)-5,6-tetramethyleneuracil, it was shown that only one of the enantiomers (R) was an inhibitor, the (S) enantiomer being totally inactive. For several of the analogues, the corresponding isomeric N(3)-acyclonucleosides were inactive as inhibitors. The results for several of the good inhibitors were compared with those of other observers for inhibi­tion of uridine phosphorylase from mammalian sources. Preliminary measurements with several of our analogues demonstrated that some of them were indeed one to two orders of magnitude more effective against the enzyme from mammalian sources.
Stereochemistry and Mechanism of Reactions Catalyzed by Tyrosine Phenol-Lyase from Escherichia intermedia
Authors: Palcic M. M. , Shen S.-J. , Schleicher E. , Kumagai H. , Sawada S. , Yamada H. , Floss H. G.
Published: August 2018

Stereochemical studies on tyrosine phenol-lyase from Escherichia intermedia have shown that the α,β-elimination reactions of ʟ-serine and ᴅ- and ʟ-tyrosine proceed with retention of config­uration at C-β. Stereospecifically (β-tritiated ʟ-serine is slowly racemized at C-β Deuterium from the α-position of ʟ-tyrosine is partially transferred to C-4 of the phenol formed when the α,β- elimination reaction is carried out in H2O, although no transfer of α-1H in 2H2O was seen. The result favors tautomerization of the p-hydroxyphenyl to a cyclohexadienonyl moiety prior to carbon-carbon bond cleavage. In the conversion of ʟ- to ᴅ-alanine catalyzed by tyrosine phenol- lyase, some a-hydrogen recycling is observed, pointing to a single-base racemization mechanism. Attempts to demonstrate cofactor motion during racemization by NaBH4 reduction of [3H]PLP- enzyme: ᴅ- and ʟ-alanine complexes failed, but showed that, as in other PLP enzymes, the holoenzyme is reduced preferentially from the Re face with respect to C-4′ of PLP and enzyme- substrate complexes preferentially from the Si face.
Divergent Evolution of 5 S rRNA Genes in Methanococcus
Authors: Wich Günter , Sibold Lionel , Böck August
Published: August 2018

The organization of genes for 5S rRNA in the methanogenic archaebacterium Methanococcus (M .) voltae and their nucleotide sequences have been determined. M. voltae possesses three 5S rRNA genes, one of them is organized in an rRNA transcriptional unit coding for 16S-23S-5S rRNA. The other two are associated with seven tRNA genes in a putative transcriptional unit composed of 5′-tRNAThr-tRNAPro-tRNATyr-tRNALys - 5S rRNA-tRNAAsp-tRNALys - 5S rRNA-tRNAAsp-3′. Coding regions plus spacers of the tRNALys-5S rRNA-tRNAAsp block of this gene cluster occur twice with identical sequence. The 5S rRNA from this cluster displays considerable sequence divergence to the rRNA operon-linked 5S rRNA gene. Comparison of the M. voltae 5S rRNA sequences with those from M. vannielii revealed that the operon-linked genes on one hand and the tRNA-linked 5S genes on the other share a greater sequence homology than the two types of genes within each of the two organisms. This indicates an independent evolution of the two sets of 5S rRNA genes without selective pressure from other ribosomal components or, alternatively, lateral gene transfer.
E. coli Maltodextrin Phosphorylase: Primary Structure and Deletion Mapping of the C-Terminal Site
Authors: Palm D. , Goerl R. , Weidinger G. , Zeier R. , Fischer B.
Published: August 2018

The complete 796 residue amino acid sequence of maltodextrin phosphorylase was deduced from the E. coli malP nucleotide sequence. The calculated molecular weight of 90 500, including pyridoxal phosphate, is significantly larger than experimentally determined values. Enzymatically active and inactive mutants following deletion or exchange of up to 8 codons (7 amino acids) at the 3′ end (C-terminus) confirm the size of the mature native enzyme and disclose the essential functional or structural role of the highly conserved C-terminal region of phosphorylases.
Versuche zur Racematspaltung von Konduramin-Analogen durch enzymatische Umesterung in organischen Lösungsmitteln /Experiments on the Optical Resolution of Conduramine Analogs by Enzymatic Transesterification in Organic Solvents
Authors: Kresze Günter , Sabuni Mahmud
Published: August 2018

A series of 1-amino-2-cyclohexene-3-ols is subjected to an enzymatic transesterification by the system lipase on silica/tributyrin (Klibanov-method). Thereby, an optical resolution of 1r-benzoyl-amido-5t,6c-dimethoxy-1-cyclohexene-4c-ol is achieved. Advantages and disadvantages of this method are discussed.
Synthese von immobilisierten Peptidfragmenten an Polystyrol-Polyoxyethylen zur Affinitätschromatographie /Synthesis of Immobilized Peptide Fragments on Polystyrene-Polyoxyethylene for Affinity Chromatography
Authors: Bayer Ernst , Hellstern Heribert , Eckstein Heiner
Published: August 2018

Polystyrene-polyoxyethylene craft copolymers have been used for step-wise peptide synthesis. After completion of synthesis the protecting groups are cleaved under acidic conditions, where the polymer-peptide bond is stable. These gels in comparison to polystyrene peptide gels, show better properties for applications in affinity chromatography as well as synthesis on solid supports, because the advantageous properties of polystyrene beads are combined with the excellent spacer behavior of polyoxyethylene chains (mobility, solvation by water and organic solvents). Peptide gels with polylysine sequences have been synthesized as highly selective stationary phases for the separation of the homologous oligo desoxyribonucleotides (dT)n with n = 1-3. The principal possibilities of these gels for affinity chromatography is demonstrated.
Synthese und Bindungsverhalten eines künstlichen Rezeptors für biogene Amine /Synthesis and Complexing Features of an Artificial Receptor for Biogenic Amines
Authors: Schmidtchen Franz P.
Published: August 2018

The synthesis of a ditopic linear receptor 3 consisting of an azacrown ether moiety for binding prim, ammonium functions and a macrotricyclic tetrahedral moiety for binding hydrophobic guest species is described. The covalent interconnection of these subunits was supposed to constitute a receptor with enhanced specificity towards dopamine-type biogenic amines. Host-guest complexa­tion was studied in a competition method with potassium ion using ion selective electrodes. The binding features of 3 with a series of biogenic amines reveal that neither the absolute binding strength nor the selectivity is enhanced in relation to the monotopic receptor 4. It is concluded that 3 does not simultaneously utilize both receptor subunits in binding the biogenic amine substrates.
Biosynthesis of Vitexin and Isovitexin: Enzymatic Synthesis of the C-Glucosylflavones Vitexin and Isovitexin with an Enzyme Preparation from Fagopyrum esculentum M. Seedlings
Authors: Kerscher F. , Franz G.
Published: August 2018

A C-glucosyltransferase from Fagopyrum esculentum seedlings catalyzes the transfer of glucose from UDP-glucose or ADP-glucose to 2-hydroxyflavanones. In cell-free enzyme preparations it was shown that only 2-hydroxyflavanones, e.g. 2,4′,5,7-tetrahydroxyflavanone and 2,5,7-trihydroxyflavanone were appropriate substrates. Naringenin, naringenin-chalcone and the flavones apigenin and chrysin cannot act as glucosyl acceptors in C-glucosyl-flavonoid biosynthesis. This demonstrates that C-glucosylation occurs after oxidation of flavanones.
Chloride Availability Affects the Malate Content and its Control by the Circadian Clock in Pulvini of Phaseolus coccineus L
Authors: Mayer W.-E. , Rüge W.A. , Starrach N. , Hampp R.
Published: August 2018

In soil-grown 3-to 4-weeks-old Phaseolus coccineus L. plants the chloride content changed antagonistically in the extensor and flexor of the laminar pulvinus during the circadian leaf movement in continuous light. This is as expected for an osmoticum involved in the volume changes of pulvinar cells. H ow ever, the malate content of extensor and flexor cells was not altered in a circadian manner. Furthermore, during light/dark cycles the malate content in both, extensor and flexor, was higher in the light than in the dark. This indicates that malate was not used in the osmotic motor of leaf movement and that its level was not controlled by the circadian clock in 3-to 4-weeks-old soil-grown plants.

When leaves were cut from 14-days-old soil-grown plants and cultured in distilled water the pulvini were depleted of chloride and the malate content was increased. In these chloride de­ prived leaves malate, and to a lesser extent citrate (about 1/10 of malate), changed antagonistically in a circadian manner in the extensor and flexor, indicating that these organic anions were now involved in the osmotic motor and under the control of the circadian clock. The similar properties of pulvinar and stomatal movements of starch-containing guard-cells are evident: in both cases, depending on the availability of chloride, CL- and/or organic anions are used for the compensation of the electrical charge of K+.
Ringöffnungsreaktionen an bioreaktiven Lactamsystemen / Ring Opening Reactions of Bioreactive Lactam Systems
Authors: Frister Hermann , Schlimme Eckhard
Published: August 2018

1-β-ᴅ-Ribofuranosylpyrrolidin-2,5-dione (9) was synthesized by ribosylation of N-silylated succinimide (7) with 1,2,3,5-tetra-O-acetyl-β-ᴅ-ribofuranose in acetonitril in the presence of tin tetrachloride. The compounds 9, 1-β-ᴅ-ribofuranosyl-l-H-pyrrol-2,5-dione (5) and N-methyl- maleinimide (2) were converted with ammonia to the ring-opened components 16. 14 and 15. The bioreactivity of the N-maleinimide derivatives 2 and 5 with respect to addition and ring-opening reactions with amino acid side chains containing either thiol or amino groups was shown in model reactions with glutathion (compds. 17,18) and lysine (compds. 19, 20). The ring opening reaction of 3-methyl-3-phenyl-1-β-ᴅ-ribofuranosylpyrrolidin-2,5-dione (11) with lysine yields 21, thus demonstrating the possibility of glycosuccinylation of amino groups in proteins.
Inhibition and Photoaffinity Labeling of Photosystem II by Thiazolyliden-ketonitriles
Authors: Bühmann U. , Herrmann E. C. , Kötter C.
Published: August 2018

A new group of photosynthetic inhibitors is described. Thiazolyliden-ketonitriles are blocking electron flow at the acceptor side of photosystem II. They displace radioactive metribuzin from the membrane. Functional properties indicate that the new inhibitors share the binding site on the herbicide binding protein D-1 identical to that of the classical triazinone/urea-type inhibitors. However, fine details in the functional inhibition pattern, like lag in the inhibition and no loss of activity in tris-treated membranes, group them more specifically among the phenol-type family of photosystem II inhibitors. By photoaffinity labeling and immunoblotting it is shown that an azido- derivative of the thiazolyliden-ketonitriles tags the 32 kDa polypeptide subunit of photosystem II. This shows that also the phenol group inhibitors interact with the D-1 protein.

MO calculations show that the predominant tautomeric form of the new ketonitrile inhibitors when bound to the membrane is the hydroxy-form, whereas cyanoacrylates with a comparable essential element are bound in the keto-form. As the first is a phenol-type, the second an urea- type inhibitor, this allows to define more clearly the essential chemical element in the phenol-type inhibitors responsible for effective binding to the D-1 protein, probably oriented in the binding niche towards histidine 215, rather than towards serine 264, as triazine/urea and the cyanoacrylate derivatives do.
The Three-Dimensional Structure of the Herbicide Binding Niche on the Reaction Center Polypeptides of Photosystem II
Authors: Trebst Achim
Published: August 2018

The folding through the membrane of the plastoquinone and herbicide binding protein subunits of photosystem II and the topology of the binding niche for plastoquinone and herbicides is described. The model is based on the homology in amino acid sequence and folding prediction from the hydropathy analysis of the D-1 and D-2 subunits of photosystem II to the reaction center polypeptides L and M of the bacterial reaction center. It incorporates the amino acid changes in the D-1 polypeptide in herbicide tolerant plants and those indicated by chemical tagging to be involved in Qв binding. It proposes homologous amino acids in the D-1/D-2 polypeptides to those indicated by the X-ray structure of the bacterial reaction center to be involved in Fe-, quinone- and reaction center chlorophyll-binding. The different chemical compounds known to interfere with Qв function are grouped into two families depending on their orientation in the Qв binding niche.
Cytogenetic Effects of the Insecticide Methamidophos in Mouse Bone Marrow and Cultured Mouse Spleen Cells*
Authors: Amer Soheir M. , Sayed Magdy A.
Published: August 2018

The cytogenetic effect of the insecticide methamidophos (0,S-dimethylphosphoroamidothiolate) was studied in mouse bone marrow and mouse spleen cells in culture. In vivo the ability of methamidophos to induce micronuclei and sisterchromatid exchange in mouse bone marrow was investigated. In vitro mouse spleen cells in culture were used to assess the ability of the insecticide to induce chromosomal aberrations and sister chromatid exchange.

Three different routes of application for the pure insecticide were tested so as to cover the different possibilities for human exposure to the insecticide. Intraperitoneal, oral and dermal treatment with metham idophos caused toxicity to marrow as indicated bv a significant increase in the percentage of polychromatic erythrocytes (PEs) over that of the control.

Methamidophos showed mutagenic potential as evidenced by a positive response in the micronucleus and chromosomal aberrations assays. Thus, single and multiple i.p. injections at 6 and 4.5 mg methamidophos/kg body w t., oral administration of the insecticide for 14 consecutive days at a dietary level of 100 ppm and multiple dermal treatments (total 4) with 24 mg/kg body wt. induced a statistically significant increase in the frequency of PEs with micronuclei in mouse bone marrow. Moreover, the tested concentrations of m etham idophos as low as 0.25 ng/ml induced a high percentage of metaphases with chromosomal aberrations in cultured mouse spleen cells.

Methamidophos is a weak inducer of SCEs in mouse bone marrow and cultured mouse spleen cells.
Alkaloids in Stem Roots of Nicotiana tabacum and Spartium junceum Transformed by Agrobacterium rhizogenes
Authors: Wink Michael , Witte Ludger
Published: August 2018

The growth of root hairs from stems of Nicotiana tabacum and Spartium junceum was induced by Agrobacterium rhizogenes. Stem roots of Nicotiana contained nicotine and a second alkaloid, probably anabasein. Root hairs from stems of Spartium contained cytisine, N methylcytisine and anagyrine as major alkaloids. The alkaloid content of the tumors was 3-12 times higher than that of the respective healthy host tissue.
Flavonoids from the Leaf Resin of Snakeweed, Gutierrezia sarothrae
Authors: Hradetzky Dagmar , Wollenweber Eckhard , Roitman James N.
Published: August 2018

The resinous material excreted by aerial parts of snakeweed, Gutierrezia sarothrae, was analyzed for flavonoid aglycones. Six major flavonoids were characterized by their spectral data; nine minor flavonoids were identified by direct comparisons with markers. The major flavones form three pairs of isomeric products, five of which are 6,8-methoxylated.
Isopulegol from Liquid Cultures of the Fungus Ceratocystis coerulescens (Ascomycotina)
Authors: Koch Wolf-Gerald , Sinnwell Volker
Published: August 2018

Ceratocystis coerulescens RWD 451 (Ascomycetes) was cultivated on defined synthetic culture medium containing glucose (3.0% ), asparagine (0.1% ), mineral salts and thiamine. 6 weeks oid cultures produced methyl heptenyl compounds, citronellol. citronellyl acetate, dihydro-farnesol and a hitherto unknown monoterpene alcohol. By GC/MS, 1H and 13C NMR spectroscopy, this alcohol could be identified as ( -)isopulegol. So far, this monocyclic monoterpene alcohol has not been described as a fungal metabolite.