bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure-Dependent Biological Activity of Racemic 1-Substituted 2-0-Hexadecylglycero-3-phosphocholines and Analogues
Authors: Kluge Siegfried , Kertscher Heinz-Peter , Ostermann Gunter
Published: August 2018

1-substituted 2-O-hexadecylglycero-3-phosphocholines and some structural analogues were tested for their biological activity on two entirely different test systems: human thrombocytes and potato virus X in tobacco plants. Structural prerequisites for a high activity in both systems are the alkyl glyceryl ether structural element, a short-chain substituent in the C-1 position, and the phosphocholine grouping. Accordingly, 1-O-methyl derivative (2) and 1-O-acetyl derivative (5) have the strongest effect on the biological activity of both test systems. The intensity of the effect of the tested compounds does not correlate with membranolytic properties measured by the lytic action on red cells
Hormone Induced Changes in Carotenoid Composition in Ricinus Cell Cultures. II. Accumulation of Rhodoxanthin during Auxin-Controlled Chromoplast Differentiation
Authors: Gemmrich Armin R. , Kayser Hartmut
Published: August 2018

The effects of auxin and cytokinin on light dependent carotenoid synthesis were studied in callus cultures derived from Ricinus endosperm tissue. Chloroplasts differentiate when calli are grown in the light in the presence of cytokinin and auxin. When cultures are transferred to an auxin-free medium, chromoplast differentiation is initiated, i.e. rhodoxanthin accumulates whereas lutein and chlorophyll content decrease and the plastid morphology changes from that of a typical chloroplast to that of a globular-type chromoplast. These changes are fully reverted by readdition of auxin. Plastid differentiation into either chloroplasts or chromoplasts in Ricinus endosperm cultures therefore appears to be controlled by auxin and cytokinin.
Notizen: Specificity of Synthetic Sex-Attractants in Zygaena Moths
Authors: Priesner Ernst , Naumann Clas M. , Stertenbrink Johannes
Published: August 2018

Species-specific sex-attractants are reported for western Palearctic Zygaena moths of the carniolica, viciae, filipendulae, and purpuralis species groups. The attractants were established by combined electrophysiological and field behavioural studies and consist of ternary combinations of (Z)-7-dodecenyl/(Z)-9-tetradecenyl acetates with a particular further (Z)-alkenyl acetate. Data on other Zygaenini taxa are included.
Characterization of Microcystis Strains by Alkyl Sulfides and β-Cyclocitral
Authors: Jiittner Friedrich
Published: August 2018

Cyanobacteria of the genus Microcystis have been found to liberate large amounts of β-cyclo- citral. While all seven strains of Microcystis studied possessed this property, it has not been found in any other cyanobacterial species. This chemical characteristic of the genus Microcystis enables the unequivocal systematic arrangement of controversial species. Another chemical property allows two chemotypes to be distinguished within the genus Microcystis: one exhibits an intensive release of isopropylmethyl disulfide, diisopropyl disulfide and diisopropyl trisulfide, substances which have not been previously found in any microorganism. The second chemotype excretes dimethyl disulfide and in some cases also dimethyl trisulfide and dimethyl tetrasulfide. Species producing isopropyl sulfides emanate an intensive sulphurous malodour.
Development-Specific Incorporation of [14C]5-Aminolevulinate and [3H]Leucine into Cytochrome c and Biliprotein in the Butterfly, Pieris brassicae. Correlation with the Ecdysteroid Titer in the Pupa
Authors: Kayser Hartmut , Krull-Savage Ute
Published: August 2018

Incorporation of [14C]5-aminolevulinate and [3H]leucine into cytochrome c, biliprotein and total soluble protein was followed from the last larval instar to the adult stage in Pieris brassicae. The titer of ecdysteroids during the pupal stage was determined with a radioimmunoassay to correlate synthesis of heme products and of protein(s) with adult differentiation. Incorporation of both precursors showed a developmental profile with high synthetic activities in feeding larvae and in pupae after the release of ecdysteroids. Variation of the hormone titer during pupal life differed significantly in males and females. Labeling of cytochrome c by both 14C and 3H was as expected from the variation of its concentration reported in a preceding paper; highest in corporation was around adult emergence. The results demonstrate that i) the accumulation of cytochrome c in the developing adult insect is primarily due to de novo synthesis of both heme and apocytochrome c, performed under coordinate control, and ii) the concentration of 5-aminolevulinate is not rate-limiting in the formation of cytochrome c. Biliverdin IXγ, the major tetrapyrrolic product in this insect, seems to be directly derived from (free) heme and relatively short-lived as deduced from a time-course study. Formation of the bilin, i.e. destruction of heme, increased concomitantly to the initiation of adult differentiation by ecdysteroids in the pupa but later decreased at adult emergence. Synthesis of cytochrome c takes place as a late event during terminal development. Thus, the pathways leading to the two major heme products seem to be differently regulated during development.
Chemical and Physical Characterization of Four Interfacial-Active Rhamnolipids from Pseudomonas spec. DSM 2874 Grown on n-Alkanes
Authors: Syldatk Christoph , Lang Siegmund , Wagner Fritz , Wray Victor , Witte Ludger
Published: August 2018

Four extracellular glycolipids produced under growth-limiting conditions were isolated from the culture broth of Pseudomonas spec. DSM 2874. After purification by column and thick-layer chromatography they were identified as anionic rhamnolipids. 1H and 13C-NMR studies showed that two of these, β(β(2-O-α-ʟ-rhamnopyranosyloxy)decanoyl)decanoic acid and β(β(2-O-α-ʟ- rhamnopyranosyl-α-ʟ-rhamnopyranosyloxy)decanoyloxy)decanoic acid, were identical with com­pounds described previously, while the other more hydrophilic compounds, β(2-O-α-ʟ-rhamno- pyranosyloxy)decanoic acid and β(2-O-β-ʟ-rhamnopyranosyl-a-ʟ-rhamnopyranosyloxy)decanoic acid, were new compounds.

Surface and interfacial activity of the organic crude extract and of the purified components were determined in different aqueous solutions. The pH-dependence of surface and interfacial properties of the two previously described rhamnolipids (4. 20. 23) were examined in Teorell- Stenhagen-buffer (supplemented with 10% NaCl) at pH 3.0 and pH 9.0. All rhamnolipids reduced the surface-tension from 72 to about 30 mɴ/m and the interfacial-tension from 42 to about 1 mɴ/m. The critical micelle concentrations were of the order of 5 to 200 mg/l depending on the structure of the molecule.
Enzymatic Nitrate Assay by a Kinetic Method Employing Escherichia coli Nitrate Reductase
Authors: Schild Johannes , Klemme Jobst-Heinrich
Published: August 2018

An enzymatic assay system for nitrate employing the membrane-bound nitrate reductase (EC 1.7.99.4) of E. coli is described. Contrary to previous enzymatic assay systems, the present method is a kinetic one, i.e. the substrate, nitrate, is assayed by measuring the reaction rate of the nitrate reductase-catalyzed reaction. Based on the observation that the nitrate reductase-catalyzed reaction obeys pseudo-first order kinetics, a test system is described allowing the assay of nitrate at a concentration as low as 1 ppm. The relatively high M ichaelis-M enten constant for nitrate (0.3 mᴍ) of the E. coli nitrate reductase favours nitrate assay by the kinetic method.
Antiserum Against the 33-kDa Herbicide-Binding Protein
Authors: Herrmann Gerhard , Thiel Andreas , Böger Peter
Published: August 2018

A rabbit antiserum was prepared against the purified 33-kDa herbicide-binding protein (HBP) from the alga Bumilleriopsis filiformis. Specificity at 1:10,000 dilution (v/v) of the unpurified serum is detectable in the immunoblotting assay with both the 33-kDa protein from the alga Bumilleriopsis as well as that from Spinacia. Agglutination can be observed with photosystem-II particles only, not with intact thylakoids, indicative of a hidden location of the protein determinants in the membrane. Neither herbicide binding nor electron transport is influenced by the antibody. Apparently, the antigenic site of the HBP for the antibody used here is different from the herbicide-binding region.
A Patch Clamp Study of Tonoplast Electrical Properties in Vacuoles Isolated from Chenopodium rubrum Suspension Cells
Authors: Bentrup Friedrich-Wilhelm , Hoffmann Bernd , Gogarten-Boekels Maria , Gogarten Johann Peter , Baumann Christian
Published: August 2018

The patch clamp technique has been applied to isolated vacuoles from green suspension cells of Chenopodium rubrum to record electrical parameters of the tonoplast. In a symmetrical K+ solution of 46 mᴍ, the membrane displays a near zero voltage, whereas 2 mᴍ ATP will hyper-polarize it to 15 or 20 mV (vacuole positive). The conductance amounts to about one S · m-2. Fluctuations of the clamp current are explained by an unknown channel species having opening times of 5 - 10 ms. Together with previous work on a tonoplast vesicle preparation and unpublished data on vacuoles from our laboratory, the present results indicate an electrogenic membrane ATPase pumping protons from the cytoplasm to the vacuole.
Calcium, Iron and Cobalt Accumulation in Root Hairs of Soybean (Glycine max)
Authors: Werner Dietrich , Kuhlmann Klaus-Peter , Gloystein Frank , Richter Friedrich-W.
Published: August 2018

Root hairs of soybeans (Glycine max), target cells for infection by Rhizobium japonicum accumulate iron more than 10-fold, cobalt more than 8-fold and calcium more than 7-fold compared to the other parts of the root system. In root hairs of wheat (Triticum aestivum) a much smaller accumulation of these elements was found. The symbiont of Glycine max, Rhizobium japonicum, is known to have a high requirement for iron, cobalt and calcium.
Growth Response of Mouse Lymphoma Cells to Low Concentrations of Mercuric Chloride
Authors: Jost Stephan Paul , Cole Jane , Goodwin Brian C.
Published: August 2018

Three growth rate experiments involving several sampling points were performed to investigate the previous finding that very low concentrations of HgCl2 inhibit the growth of murine lymphoblasts in vitro. However, results presented here do not confirm this, there being no significant differences between the three independent growth rate experiments.
Acetate Concentration and Chloroplast Pyruvate Dehydrogenase Complex in Spinacia oleracea Leaf Cells
Authors: Liedvogel Bodo
Published: August 2018

Acetate concentration in spinach (Spinacia oleracea L.) leaf tissue has been determined by direct measurement in a leaf extract to be 70 μᴍ or less. Additional evidence for such low acetate levels came from isotope dilution experiments where the [l-14C]acetate incorporation into fatty acids was assayed using purified chloroplasts in the presence of tissue extracts. Pyruvate dehydrogenase complex activity was shown to be present in spinach chloroplasts and was determined by a newly developed acetyl coenzyme A trapping system (100 nmol acetyl CoA formed per mg chloroplast protein per h). The problems of acetyl CoA synthesis in both compart­ments, chloroplasts and cytoplasm, are discussed in this context.
Small-Angle X-Ray and Light Scattering Studies on the Influence of Mg2+ Ions on the Structure of the RNA from Bacteriophage MS 2
Authors: Ribitsch Gertraud , Clercq Rita De , Folkhard Waltraud , Zipper Peter , Schurz Josef , Clauwaert Julius
Published: August 2018

The influence of Mg2+ ions on the secondary and tertiary structure of the RNA from bacteriophage MS2 was investigated by small-angle X-ray scattering and light scattering and by sedimentation experiments.

The analysis of the outer part of the X-ray scattering curve obtained at low temperature in the absence of Mg2+ yielded a cross-section radius of gyration of 0.88 nm and a mass per unit length of 1720 g mol-1 nm-1. Very similar values for these parameters, which refer to the secondary structure of the RNA molecule, were also derived from the X-ray scattering curves obtained in the presence of different amounts of Mg2+ (0.07 to 1 ions per nucleotide). On the contrary, the inner part of the X-ray scattering curves turned out to be highly dependent on the Mg2+ concen­tration: the cross-section radius of gyration and the mass per unit length, which were determined from the scattering curves at small angles as parameters related to the tertiary structure of the RNA, amounted to 3.11 nm and 4000 g mol-1 nm-1, respectively, in the absence of Mg2+ and in­creased significantly upon raising the concentration of Mg2+. The increase of these structural parameters was found to be accompanied by a decrease of the overall radius of gyration (as revealed indirectly by X-ray scattering and directly by light scattering measurements) and by an increase of the sedimentation coefficient.

The results from the investigations of the RNA at low temperature clearly establish the existence of double-stranded structures down to very low Mg2+ concentrations as well as the occurrence of Mg2+ induced changes of the tertiary structure. In the absence of Mg2+ the RNA molecule appears to be a rodlike particle of about 300 nm length with a lateral diameter of about 9 to 11 nm. Upon addition of increasing amounts of Mg2+ this extended structure tightens, eventually forming a coil-like particle. Previous X-ray scattering experiments with MS2 RNA at ionic strength 0.1 (Zipper, Folkhard and Clauwaert, FEBS Lett. 56, 283-287 (1975)) have already established the axial dimensions of such coil-like particles to be about 63, 31 and 14 nm.

The results from supplementary X-ray scattering experiments performed at higher temperatures in the absence or presence of Mg2+ clearly reflect the loss of secondary structure due to melting of the RNA. This loss is, however, less pronounced at higher concentrations of Mg2+ .
Properties of Lectins from Snails of the Genus Helix Probed by Monoclonal Antibodies
Authors: Schneider Hansjörg A. W.
Published: August 2018

Helix-Lectins, Monoclonal Antibodies against Lectins, C om petition between Antibodies and Carbohydrates Monoclonal antibodies were raised against the lectin of H elix pom atia (HPL). Besides anti­ bodies bearing the more common y and x chains, antibodies with a, /j. and X2 chains were elicited. The anti-HPL antibodies are expected to be useful in studies on HPL biogenesis and HPL sub­ structure and in studies concerned with the binding of HPL to cell surfaces. Binding of carbohydrates to HPL im paired the binding of anti-H PL antibodies. One to 3 m M GalNAc inhibited HPL-binding in two out of nine antibodies. None of the antibodies bound in the presence of micrograms per ml of the polyvalent blood group A-substance from hog stomach. Similarly, all anti-HPL antibodies were prevented from binding if non-inhibitory concentrations of A-substance were supplem ented with GalNAc. Lectins from H elix aspersa (HAL) and H elix lucorum (H LL) differed from HPL in antigenic properties. Only one anti-HPL antibody each bound these lectins as well as HPL. Binding of lectins of Cepaea and Rapana was scarcely detectable. Most of the anti-HPL antibodies and the m ultivalent H PL-antigens formed precipitation lines in double diffusion tests. At least two antibodies (IgMs) did so with HLL but none with HAL. The possibility that antibodies were selected because of unknown interactions between HPL and the carbohydrate moieties of certain fractions of antibodies was excluded by raising the antibodies in the presence of tunicamycin to inhibit N-glycosylation.
Untersuchungen zur Sterinsynthese des Ascomyceten Aureobasidium (Dematium) pullulans / Studies of the Sterolsynthesis in the Fungus Aureobasidium (Dematium) pullulans
Authors: Flesch Peter , Schaefer Michael
Published: August 2018

Isolation and identification of sterols from culture extracts of the fungus Aureobasidium (Dematium) pullulans yielded metabolites with key function in sterol synthesis. By proof of squalene, lanosterol/dihydrolanosterol, desmosterol, ergosterol, cholesterol, stigmasterol and β-sitosterol it was possible to work out a general synthesis-scheme for the building-up of sundry sterols in Ascomycetes.
Fluorescence-ODMR of Light Harvesting Pigments of Photosynthetic Bacteria
Authors: Angerhofer A. , Schütz J. U. von , Wolf H. C.
Published: August 2018

Fluorescence detected ODMR measurements in zero field on the triplet states of light harvest­ing (LH) pigments in chromatophores from Rhodopseudomonas sphaeroides R 26.1 and Rhodo­pseudom onas capsulata A1a+ are reported. In both cases at least two distinct triplet states in the antenna system with zfs values of D between 209 and 217 and E between 56 and 67 x 10-4 cm-1 are observed.
Isomerase and Decarboxylase Activities in the 4-Hydroxyphenylacetate Catabolic Pathway of Pseudomonas putida
Authors: Martín M. L. , Garrido-Pertierra A.
Published: August 2018

5-Carboxymethyl-2-hydroxymuconate isomerase and 5-carboxymethyl-2-oxo-hex-3-ene-1,6-dioate decarboxylase in the 4-hydroxyphenylacetate meta-cleavage pathway have been purified to over 98% homogeneity. The native enzymes, which appear to be monomers, have apparent molecular weights of 37,000. The isomerase shows a pH optimum 8.0 and does not require ions for its catalytic activity; Mg2+ is required for the decarboxylase reaction. Apparent Km values for their respective substrates are 2.8 × 10-4м for the isomerase and 1.4 × 10-4м for the decarboxy­ lase. The highly purified enzymes were used to study the spectral characteristics of the decarboxy­ lase substrate.
Invariance of Stoichiometry of the Sarcoplasmic Reticulum Calcium Pump at Physiological Calcium Concentrations – a Reevaluation
Authors: Hasselbach Wilhelm , Migala Andrea
Published: August 2018

The decline of the transport ratio of the sarcoplasmic calcium pump observed in a recent study (A. results from the retardation of calcium oxalate precipitation at low calcium/protein ratios. The prevailing high internal calcium level supports a rapid calcium backflux and a compensatory ATP hydrolysis during net calcium uptake which reduces the transport ratio. Yet, the determined calcium back­ flux does not fully account for the decline of the transport ratio. A supposed modulation of the stoichiometry of the pump by external calcium (0.1 μм) is at variance with results of previous studies showing a constant transport ratio of two in the same calcium concentration range.
On the Active Principles of the Spurge Family (Euphorbiaceae) XI. [1] The Skin Irritant and Tumor Promoting Diterpene Esters of Euphorbia tirucalli L. Originating from South Africa
Authors: Fürstenberger G. , Hecker E.
Published: August 2018

The irritant and tumor-promoting constituents of latex of Euphorbia urucalli L. originating from South Africa were isolated. They were identified as irritant ingenane and tiglianc type diterpene esters derived from unsaturated aliphatic acids and acetic acid and the polyfunctional diterpene parent alcohols 4-deoxyphorbol, phorbol and ingenol, respectively.

The irritant and tumor-promoting esters of 4-deoxyphorbol are predominant and were fully characterized chemically and biologically. They are positionally isomeric 12,13-acylates, acetates e.g. Euphorbiafactors Ti1 -Ti4. As acyl groups they carry homologous, highly unsaturated aliphatic acids of the general structure CH3-(CH2)m-(CH = CH)n-COOH (m = 2,4; n =1,2,3,4,5; N = 2n + m + 2). Corresponding diesters of 4-deoxy-4α-phorbol are also present which are biologically inactive. Comparison of structures and biological activities of 12,13-diesters of 4-deoxyphorbol indicates that - for a distinct total number of C-atoms (N) in the acyl moiety - an increasing number of conjugated double bonds In} may increase the irritant but decrease the tumor-promoting activity. Replacement of the hydroxyl function at C-4 (phorbol-12,13-diesters) by hydrogen (corresponding 4-deoxyphorbol-12,13-diesters) does not essentially alter biological activities. Epimerization of 4-deoxyphorbol-12,13-diesters at C-4 abolishes biological activities.

The specific chemical properties demonstrated for the diterpene ester irritants contained in the latex of E. tirucalli and hence in all plant parts may be useful in trials to abolish the potential risk of cancer involved especially in occupational mass production and handling of the plant. Some of the structure activity relations of the Euphorbia factors isolated made them excellent tools in experimental cancer research for the analysis of mechanisms of tumorigenesis.
(Z)-9-Dodecenyl Acetate, a Component of the Sex Pheromone of Cnephasia longana Haworth (Lepidoptera: Tortricidae)
Authors: Bestmann Hans-Jürgen , Attygalle Athula , Platz Hans , Vostrowsky Otto , Glas Michael
Published: August 2018

By means of electrophysiological investigations, GC- and GCMS-analysis of gland extracts and GC-analysis with EAG-detection (Z)-9-dodecenyl acetate was proven to be a component of the sex pheromone of female Cnephasia longana moths. (E)-9-dodecenyl acetate acts as a pheromone inhibitor, as shown by field trials.
Separation of Chloroplast Thylakoid Membrane Polypeptides by Electrophoresis on Polyacrylamide Gradient Gels with a Length of 60 cm
Authors: Schmidt H. Oskar , Süss Karl-Heinz
Published: August 2018

14C labeled thylakoid membranes of Vicia faba chloroplasts were separated by one-dimensional electrophoresis in gel cuvettes of different length using a 12 - 18% polyacrylamide gradient gel system containing 0.1% sodiumodecylsulfate and 6 ᴍ urea. The use of gels with a length of 22 cm and 60 cm led to the detection of about 40 and 80 polypeptide bands, respectively, after dye staining and 50 and more than 100 polypeptide bands, respectively, after autoradiography. The conditions used strongly denaturate chlorophyll proteins and avoid the formation of different polypeptide conformations. Polypeptides differing in molecular mass from about 3000 to 70000 were separated in sharp bands.
Phosphorylation of Coformycin and 2′ -Deoxycoformycin, and Substrate and Inhibitor Properties of the Nucleosides and Nucleotides in Several Enzyme Systems
Authors: Bzowska Agnieszka , Lassota Piotr , Shugara David
Published: August 2018

Under conditions where 2′-deoxycoformycin is enzymatically phosphorylated by wheat shoot phosphotransferase to the 5′-phosphate in 15 - 20% yield, coformycin is a relatively poor substrate, and is phosphorylated only to the extent of ≤ 5%. However, chemical phosphorylation of coformycin by modifications of the Yoshikawa procedure led to isolation of coformycin-5′-phosphate in 20% overall yield.

Coformycin-5′-phosphate was characterized by various criteria, including 1H NMR spectroscopy. Comparison of the spectrum with that of the parent nucleoside indicated that the nucleotide is predominantly, although not exclusively, in the conformation anti about the glycosidic bond.

Like 2′-deoxycoformycin-5′-phosphate, coformycin-5′-phosphate was a feeble substrate of snake venom 5′-nucleotidase, and is hydrolyzed, quantitatively, at only 2% the rate for 5′-AMP. With 5′-AMP analogues as substrate, the 5′-phosphates of both coformycin and deoxycoformycin were poor inhibitors of the enzyme, with Ki values > 0.3 mᴍ.

The 5′-phosphates of both coformycin and deoxycoformycin do not significantly inhibit adenosine deaminase (Ki > 0.2 mᴍ), but are potent inhibitors of adenylate deaminase {Ki ≤ 10−9 ᴍ). Neither coformycin nor deoxycoformycin are inhibitors of mammalian purine nucleoside phosphorylase.

The stabilities of coformycin, deoxycoformycin, and their 5′-phosphates, have been examined as a function of pH, and nature of the buffer medium. In particular, all exhibit instability in acid and neutral media, but are relatively stable in the vicinity of pH 9. Some biological aspects of the overall results are presented.
Stereospecific Synthesis by the Sodium Salt Glycosylation Method of Halogeno Benzimidazole 2′ -Deoxyribose Analogues of the Inhibitor of hnRNA Synthesis, 5,6-Dichloro-1-(β-ᴅ-ribofuranosyl)benzimidazole (DRB)
Authors: Kazimierczuk Z. , Stolarski R. , Shugar D .
Published: August 2018

The recently developed stereospecific sodium salt glycosylation procedure has been successfully applied to the synthesis of the β-ᴅ-2′-deoxyribofuranosides of benzimidazole, 5,6-dihalogeno benzimidazoles, and some 2-substituted analogues in high yield. The 5,6-dibromo analogue was obtained by bromination of the parent nucleoside. These have all been characterized by spectro­scopic methods, including 1H NMR, which permitted analyses of their solution conformations and comparison with those of the corresponding ribofuranosides. Some biological aspects, including preliminary results on cytotoxicity and antiviral activity, are briefly considered.
Biotransformation of Tryptophan to Indole-3-acetic Acid by Xanthomonas campestris pv. campestris
Authors: Robeson David J. , Cook Douglas R.
Published: August 2018

Xanthomonas campestris pv. campestris produced in-dole-3-acetic acid when grown in liquid culture in the presence of certain minimum levels of tryptophan.
Associations of Mitochondria with Desmosome-Like Structures in the Oocytes of Raillietiella aegypti (Pentastomida, Cephalobaenida)
Authors: Riehl Rüdiger , Walldorf Volker
Published: August 2018

The oocytes of the cephalobaenid Pentastomid Rail­lietiella aegypti were studied by electron microscopy. A prominent feature of vitellogenic oocytes are numerous spherical, oval and elongated mitochondria. Some of these are shown with desmosome-like structures. The associations between mitochondria and the desmosome-like structures have always been observed to lie freely in the oocyto-plasm; there are no apparent connections with the oocytous plasma membrane. Possible functional roles of these complexes are evaluated.
Biosynthesis of Daphnetin in Daphne mezereum L.
Authors: Brown Stewart A.
Published: August 2018

Shoots of Daphne mezereum synthesized daphnetin (7,8-dihydroxycoumarin) more efficiently from [2-14C]umbelliferone (7-hydroxycoumarin) than from [2-14C]p-coumaric acid, and [2-14C]caffeic acid was more poorly utilized still. These findings do not support the idea of derivation of daphnetin via hydroxylation of the caffeic acid ring at the 2 position, followed by lactone ring formation; instead they are consistent with the concept of daphnetin formation by an additional hydroxylation of umbelliferone at C-8. Umbelliferone was recovered with little l4C dilution from emulsin-hydrolysed extracts of shoots fed labelled umbelliferone, and TLC of extracts from untreated shoots revealed two substances yielding umbelliferone on hydrolysis. Evidence is presented from TLC and HP LC analysis that one of these is skimmin (7-O-β-ᴅ -glucosylumbelliferone), not previously reported from Daphne. The tracer experiments further support the theory that umbelliferone is the general precursor of coumarins bearing two or more hydroxyl functions on the aromatic ring.
A Large Chloroplast Thioredoxin ƒ Found in Green Algae
Authors: Langlotz Petra , Wagner Wolfgang , Follmann Hartmut
Published: August 2018

Unicellular green algae differ from plant leaves in their thioredoxin profile. Besides several thioredoxins of regular size (Mr = 12,000), the heat-stable protein fraction of extracts from Scenedesmus obliquus cells contains a large protein of molecular weight Mr - 28,000 which is designated thioredoxin ƒ on the basis of typical properties, in particular by its capacity to stimulate spinach chloroplast fructose-bis-phosphatase and, to lower degree, E. coli ribonucleotide reductase. The new thioredoxin was purified to apparent homogeneity by chromatography on DEAE cellulose, Sephadex G-50. CM cellulose, and Blue Sepharose. When tested in homologous enzyme systems, reduced thioredoxin ƒ strongly activated algal fructose-bis-phosphatase, but was inactive towards the cytoplasmic algal ribonucleotide reductase; NADP malate dehydrogenase was also stimulated. The protein is missing in extracts from a chloroplast-free mutant strain, C-2A′, but appears together with other chloroplast components upon illumination. Protein ƒ is therefore the main chloroplast thioredoxin of the green algae, probably corresponding to the smaller leaf chloroplast thioredoxins ƒ and m combined. Algal thioredoxin ƒ appears closely related, however, to the large thioredoxin found in a cyanobacterium, Anabaena sp.
Alterations in the Activities of Rabbit Erythrocyte Membrane-Bound Enzymes Induced by Cholesterol Enrichment and Depletion Procedures
Authors: Kamber Elli , Kopeikina-Tsiboukidou Liudmila
Published: August 2018

The effect of cholesterol enrichment and depletion of rabbit erythrocytes on the activities of membrane-bound enzymes, namely (Na+ ,K+)-stimulated ATPase. NAD+ ase and acetylcholinesterase was examined.

The cholesterol content of erythrocyte membranes has been modified by incubation of intact cells with sonicated egg lecithin/cholesterol vesicles (cholesterol/phospholipid molar ratio approx. 2) and with egg lecithin vesicles for time intervals up to 10 hours. The cholesterol/phospholipid molar ratio (CH /PL) of untreated rabbit red blood cell membranes was 0 .92-0.94. Linear increase (up to CH/PL molar ratio 1.72-1.9) or decrease (up to CH/PL molar ratio 0.27 - 0.43) in cholesterol content of erythrocyte membranes was observed over the 10 hours of incubation with egg lecithin/cholesterol and egg lecithin liposomes respectively. Fusion of liposom es to the m em brane or their attachment to the membrane surface was not a significant factor in the alteration of CH/PL ratio. (N+,K+ )-stimulated ATPase, NAD+ ase and acetylcholinesterase activities were measured as a function of membrane cholesterol. The specific activities of all three enzymes were progressively decreased with increase in cholesterol content. Partial reversibility of the inhibitory effect of cholesterol was demonstrated by measurements on cells depleted again after cholesterol enrichment. This was confirmed by the fact that a lowering in cholesterol content evoked an analogous activation of enzymes. The possible implications of physicochemical modifications of bulk and annular lipids of membrane-bound enzymes in the inhibition mechanism are discussed.
Stimulation of Phosphatidylinositol Phosphorylation in the Sarcoplasmic Reticular Ca2+-Transport ATPase by Vanadate
Authors: Varsányi Magdolna , Behle Gabriele , Schäfer Michaela
Published: August 2018

Vanadate increases the initial phosphatidylinositolphosphate formation rate as well as the steady state level of the above lipid phosphate when phosphatidylinositol associated with the isolated Ca2+ transport ATPase is phosphorylated either by the membrane bound endogeneously present phosphatidylinositol-kinase or by exogeneously added lipid kinase. Employing an ultrasonicated mixture of pure phosphatidylinositol and Triton X 100 (without membrane proteins) no vanadate effect can be seen. This vanadate effect is probably not mediated through the lipid kinase activity, but more likely, through conformational changes of the Ca2+ transport ATPase protein. Such conformational changes would lead to a higher degree of phosphatidylinositol exposed on the Ca2+ transport ATPase and thus a higher substrate concentration. Consequently, the initial phosphatidylinositolphosphate formation rate and steady state level increase.
Notizen: Influence of Temperature on the Transport of Ascorbate across Artificial Membranes as Studied by the Spin Label Technique
Authors: Lohmann W. , Tian P. z. , Holz D.
Published: August 2018

The effect of temperature on the permeation of vitamin C across membranes of DPPC vesicles labelled with the spin label 1,14 has been investigated. It could be shown that at temperatures above 40 °C the permeation rate is diminished considerably despite the fact that, at these temperatures, the spin label can rotate freely (above phase transition temperature) indicating that the membrane is more fluid. The results obtained agree well with previous findings (W. Lohmann and D. Holz. Biophys. Struct. Mech. 10, 197 (1984)) according to which the furanoid ring formed by the side chain of this vitamin opens at these temperatures. The existence of a bicyclic side-chain structure seems to be a prerequisite for the permeation of vitamin C.
Pentachlorophenol Inhibits Photosynthetic Electron Flow and Quenches Chlorophyll Fluorescence after Preillumination
Authors: Niehrs Christof , Ahlers Jan
Published: August 2018

The pesticide PCP was shown to inhibit the Hill reaction in broken chloroplasts (I50 = 15 μᴍ) and to quench chlorophyll fluorescence. Both effects require preillumination. In contrast to the common “phenol-type” inhibitors, neither inhibition of Hill reaction nor chlorophyll fluorescence quench were affected by pretreatment of chloroplast with trypsin instead of preillumination. An inhibition site differing from the “phenol type” inhibitors is therefore assumed. The results presented indicate that the observed light requirement is due to electron transport through PS II. Measurements of intrinsic tryptophane fluorescence relate the PCP site of binding to a hydro- phobic environment.
Orientation Measurements on Ordered Multibilayers of Phospholipids and Sphingolipids from Synthetic and Natural Origin by ATR Fourier Transform Infrared Spectroscopy
Authors: Brandenburg Klaus , Seydel Ulrich
Published: August 2018

Fourier-transform infrared spectroscopy was applied to natural and synthetic planar membrane multibilayer systems made from phospholipids and sphingolipids to perform orientational measurements utilizing the attenuated total reflectance technique. Applying polarized infrared light, the dichroic ratios and the positions of the peak maxima of various infrared-active bands in dependence on temperature and degree of hydration as well as the phase behaviour were studied. Under certain assumptions - which are discussed - made for the order parameter S, the orientation of various functional groups with respect to the molecular axis or to the membrane normal can be determined. For the gel phase values for S between 0.80 ± 0.05 for the complete molecule and 0.40 ± 0.05 for the end methyl group and for the liquid crystalline phase a value of 0.50 ± 0.05 were approximated. Applying these data, a relatively precise determination of the angles of the oscillating dipole moments of various functional groups could be performed, which - for some vibrations - deviate considerably from those angles assumed earlier. Regarding the phase behaviour, it was found that not only the degree of hydration but the amount of bulk water of the sample has a strong influence on the phase transition temperature Tc (lyotrophism), but only a weak influence on the orientational data.
A Serum-Free in vitro Culture System for Crayfish Organs
Authors: Gellissen Gerd , Traub Marco , Spindler Klaus-Dieter
Published: August 2018

Midgut gland and hypodermis of the crayfish Astacus leptodactylus have been cultured in a serum-free medium for several days. The medium consists of 1 part of van Harreveld solution and 1 part of an amino acid mixture supplemented with 1.2 mᴍ Na2HP04, 12 mᴍ Hepes and 80 mᴍ glucose. The antibiotics penicillin (15 mg/l) and streptomycin (25 mg/1) were added for long term culturing. This medium, called TG medium, allows the maintainance of the tissues for more than 100 h without any loss of their viability with respect to protein synthesis and secretion.
Use of Immunotitration to Demonstrate Phytochrome-Mediated Synthesis de novo of Chalcone Synthase and Phenylalanine Ammonia Lyase in Mustard Seedling Cotyledons
Authors: Brödenfeldt Reiner , Mohr Hans
Published: August 2018

The suggestion [H. J. Newbury and H. Smith, Eur. J. Biochem. 117, 575-580 (1981)] of a posttranslational activation of accumulated enzyme precursor by phytochrome was tested in the case of phytochrome-mediated induction of chalcone synthase (EC 2.3.1.74) in mustard seedlings. The approach of immunotitration of enzyme activity was adopted since it allows to relate the amount of antigenic material present in a particular extract to the extract’s enzymatic activity. The data obtained show that under all experimental conditions enzyme activity of an extract is proportional to the amount of im munoresponsive material. No indication was found either of lightdependent modification of the enzyme or of enzymatically inactive immunoresponsive material in extracts prepared from dark-grown mustard seedlings or from light-treated seedlings placed again in darkness. In model experiments with purified ribulose-bisphosphate carboxylase (EC 4.1.1.39) heat-inactivated enzyme was detected by the antibodies. Experiments on induction of phenylalanine ammonia lyase (EC 4.3.1.5) by phytochrome in mustard cotyledons support the result - synthesis de novo of enzyme protein - obtained previously [W. Tong and P. Schöpfer, Proc. Nat. Acad. Sci. U.S.A. 43, 4017-4021 (1976)] with the technique of density labelling. It is concluded that the phytochrome-mediated induction of enzymes involved in anthocyanin formation in mustard cotyledons is due to synthesis de novo of enzyme protein.
Basalflecke und Fleckenlosigkeit in Mohnblüten: Eine chemogenetische Charakterisierung / Basal Blotches and Blotchlessness of Poppy Flowers: A Chemogenetic Characterization
Authors: Böhm H.
Published: August 2018

While Papaver bracteatum and P. pseudo-orientale exhibit large basal blotches in red flowers, these marks are absent in the flowers of their close relative P. orientale. Crossing of the latter species with the former ones surprisingly resulted in hybrids showing blotchlessness. In contrast, the hybrid derived from the interspecific cross P. sommniferum x P. orientale forms relatively small but distinct basal blotches. The first parent has marked, white flowers and another basic number of the genome (x = 11) than P. orientale and its relatives have (x = 7).

Chromatographic analysis confirm ed that pelargonidin and cyanidin are the anthocyanidins of poppy flowers. Basal blotches differ from the other parts of petals since they exclusively contain cyanidin glycosides. If they are absent, pelargonidin glycosides homogeneously colour the petals.

It is concluded that in blotchless flowers of P. orientale and its hybrids the gene responsible for the 3′-hydroxylation of C15 molecules is repressed. This situation is obviously restricted to the basal areas of petals.
Phytoalexin Production by Isolated Soybean Protoplasts
Authors: Mieth Hannelore , Speth Volker , Ebel Jürgen
Published: August 2018

Protoplasts isolated enzymatically from suspension-cultured cells of soybean (Glycine max L. Merr., cv. Harosoy 63) were used to study the production of the isoflavonoid-derived phytoale­xin, glyceollin. A large enhancement in the in vivo rates of synthesis and catalytic activities of two of the enzymes associated with glyceollin biosynthesis, phenylalanine ammonia-lyase and chalcone synthase, preceded phytoalexin accumulation during early stages of culture of isolated protoplasts while cell wall regeneration occurred. A glucan elicitor from cell walls of the fungus Phytophthora megasperm a f. sp. glycinea, an effective inducer of the phytoalexin response in cultured cells, was not capable of enhancing phytoalexin formation in protoplasts. Lack of respon­siveness of the protoplasts to the glucan elicitor could either be associated with their stressed metabolic state in which the response system is already saturated or with the removal from cultured cells of an essential factor of the glucan elicitor-mediated phytoalexin induction during protoplast isolation. At least two components of the protoplast isolation medium, the osmoticum and the fungal endopolygalacturonase, have the potential to initiate the observed phytoalexin synthesis during protoplast isolation. Our results indicate that under the methods employed isolated soybean protoplasts display a stress response which other types of soybean cells show following microbial attack or treatment with elicitor.
Minimal Time Requirement for Lasting Elicitor Effects in Cultured Parsley Cells
Authors: Strasser Heiner , Matern Ulrich
Published: August 2018

Elicitor preparations derived from cell walls of phytopathogenic Alternaria spp. rapidly inhibited uptake of both inorganic phosphate and amino acids by cultured parsley cells. The inhibition of phosphate uptake was completely reversed if the elicitor was removed within a time period of approximately 20 min following its addition to the cell cultures. Cells which had been exposed to the elicitor for more than 20 min prior to washing, however, exhibited an increasingly reduced rate of phosphate uptake as compared to non-induced controls. Maximal inhibition of phosphate uptake (about 30 to 40% of the controls) required 40 min or more of elicitor treatment. These results confirm that a minimal time of exposure to elicitor of about 20 min is necessary to induce lasting effects in parsley cells. Moreover, the initial inhibition of amino acid uptake into the parsley cells suggests that the elicitor rapidly decharged the plasmalemma potential of the cells.
Flow Cytometric DNA-Analysis of Plant Protoplasts Stained with DAPI
Authors: Ulrich Ingunn , Ulrich Wolfgang
Published: August 2018

prepared from leaves of various higher plants were stained with the specific DNA fluorochrome DAPI and measured with a pulse cytophotometer. DNA distribution curves of protoplasts showed DNA histograms like assays of animal cells stained with the same dye solu­tion. The percentage of fractions of cell populations in G0/G1-, S- and G2 + M-phase of the cell cycle could be calculated. A simple method of protoplasts preparation and of flow cytometric estimation of DAPI stained plant protoplasts is described. This method allows cytogenetic and cytokinetic studies of cells from plant material and may be used for fluorescence activated cell sorting.
The Expression of the Isovitexin 7-O-Xylosylating Gene gX in Silene pratensis and S. dioica is Restricted to the Petals
Authors: Steyns Jan , Brederode Jan v.
Published: August 2018

The isovitexin-O-glycosylation patterns of rosette leaves, stem leaves and petals of Silene dioica plants were investigated. The 7-O -xylosylation of isovitexin, controlled by gene gX, only occurs in the petals. In the leaves isovitexin is 7-O -galactosylated, which is controlled by gene Xgal. Acyl groups may be linked to either the 7-O- or the 2″-O-substituted sugar; the former only occurs in the leaves, whereas the latter takes place both in leaves and petals. The restriction of the gX controlled enzyme activity and its product to the petals of Silene dioica plants is in complete agreement with previously obtained results (reference [2]) on the expression of g X in the genetic background of the closely related Silene pratensis, into which gX can be introduced by introgressive hybridization.

On the basis of serological enzym e inhibition studies, it is argued that the absence of 7-O-xylosylation in the leaves is not due to post-translational inactivation of the gX controlled enzyme. The regulation of the expression of gene gX throughout ontogeny therefore differs markedly from that of two allelic g locus variants, controlling the 7-O-glucosylation of isovitexin.
Preparation of Pheromones by Simple Procedures
Authors: Mangold H. K. , Becker H.
Published: August 2018

(Z)-9-Tetradecenyl methanesulfonate derived from (Z)-9-tetradecenoic acid (myristoleic acid) of beef tallow served as starting material for the preparation of sets of alcohols, alkyl acetates, and aldehydes having 16 and 18 carbon atoms. These com pounds are known to function as pheromones in various insect species. Chain elongation of (Z)-9-tetradecenyl methanesulfonate by malonic ester synthesis follow ed by esterification afforded the methyl ester of (Z )-11-hexadecenoic acid. This ester was converted to a set of pherom ones having a C16-chain with a (Z)-double bond in position 11. Chain elongation of (Z )-11-hexadecenyl methanesulfonate yielded the m ethyl ester of (Z)-13-octadecenoic acid which was used for the preparation of a set of pheromones having a C18-chain with a (Z)-double bond in position 13. All the reaction steps involved provided excellent yields.
Photocontrol of Chloroplast Lipids in Fern Gametophytes
Authors: Kraiss Stefan , Gemmrich Armin R.
Published: August 2018

In the gametophyte of the fern Anemia phyllitidis synthesis of linolenic acid esterified in monogalactosyldiglyceride requires light. By induction-reversion experim ents it could be demonstrated that this light-dependent step is mediated by phytochrome. There is also evidence for phytochrome control of galactolipid and hexadecatrienoic acid synthesis. In continuous blue light the synthesis of linolenic acid is inhibited and linoleic acid accumulates. It is concluded that the blue light photoreceptor affects an inhibition of linoleic acid desaturase. In continuous blue light chloroplasts contain abundant multilayered thylakoids, the grana regions are not as distinct as in white light, and membranes appear less appressed. In continuous red light the membranes are reduced in number and contain less grana-like appressions. It is concluded that both photoreceptors are necessary for a coordinate synthesis and assembly of the individual components of the chloroplast membrane.
Colletruncoic Acid Methyl Ester, a Unique Meroterpenoid from Colletotrichum truncatum
Authors: Stoessl Albert , Stothers J. B.
Published: August 2018

Metabolites isolated from the soybean pathogen Colletotrichum truncatum were identified as meso- and ᴅ-( -)-butane-2,3-diol and the previously unreported compound , colletruncoic acid methyl ester, to which structure 1 is assigned mainly on 1H - and 13CMR evidence. The compound has a skeleton unprecedented for a fungal polyketide. The previously unknown 2-hydroxymethylhexa-2,4-dienol was also isolated.
6-(Hydroxythio) carbonyIpyridin-2-carbonsäure und Pyridin-2-carbon- säure-6-monothiocarbonsäure als biosynthetische Zwischenstufen bei der Bildung von Pyridin-2,6-di(monothiocarbonsäure) aus Pyridin-2,6- dicarbonsäure [1] / 6-(Hydroxythio)carbonylpyridine-2-carboxylic Acid and Pyridine-2-carboxylic Acid-6- monothiocarboxylic Acid as Interm ediates in the Biosynthesis of Pyridine-2,6-di(monothiocarboxylic Acid) from Pyridine-2,6-dicarboxylic Acid [1]
Authors: Hildebrand U. , Taraz K. , Budzikiewicz H.
Published: August 2018

It is shown by feeding experiments with [3-2H]pyridine-2,6 -dicarboxylic acid that 6 -(hydroxythio)carbonylpyridine-2-carboxylic acid and pyridine-2 -carboxylic acid-6-m onothiocarboxylic acid are intermediates in the biosynthesis of pyridine-2,6 -di(monothiocarboxylic acid) from pyridine-2,6 -dicarboxylic acid produced by Pseudomonas putida. Thus the series of biosynthetic steps - COOH → - CO - SOH → COSH has been demonstrated for the first time.