bluuebunny/crossref_metadata_2025 huggingface dataset:
Natural Inhibitors of Germination and Growth, V Possible Allelopathic Effects of Compounds from Thuja occidentalis
Authors: Oster Ulrike , Spraul Martin , Rüdiger Wolfhart
Published: August 2018

Volatile compounds which are released from fresh leaves of Thuja occidentalis inhibited germination of seeds of Amaranthus caudatus and Lepidium sativum. The volatile compounds were obtained by a vacuum method applied to the leaves, by direct analysis of the content of secretory organs and by solvent extraction of leaves. The bioactive compounds proved to be monoterpenes. The highest bioactivity were found for alcoholic compounds followed by ketones, esters and finally hydrocarbons. Non-volatile germination inhibitors which were ex- tracted with hot water were abscisic acid (3-4 µg/g fresh weight of leaves), and two oxidation products of thujone, 2-[2′-acetyl-l′-isopropyl]cyclopropylacetic acid (“Thujaketosaure”) and 3-isopropyl-5-oxohex-2-enoic acid. These compounds could also be prepared from thujone. The relationship of these compounds with possible allelopathic effects of Thuja occidentalis is discussed.
Fulvoferruginin, a Carotane Antibiotic from Marasmius fulvoferrugineus Gilliam [1]
Authors: Klein Joachim , Anke Timm , Sheldrick William S. , Bross Monika , Steffan Bert , Steglich Wolfgang
Published: August 2018

The structure of fulvoferruginin (1), a carotane derivative from cultures of Marasmius fulvoferrugineus, has been established by spectroscopic investigations and an X -ray structure analysis. 1 exhibits antibacterial, antifungal. and cytotoxic activities.
Hyaluronic Acid-Like Substance from Mouse Ovaries with Angiogenic Activity
Authors: Sato Eimei , Miyamoto Hajime , Koide Samuel S.
Published: August 2018

Glycosaminoglycans prepared from extracts of non-luleal mouse ovaries (JCL-ICR strain) were assayed for neovascularization by implanting Elvax films, impregnated with test samples, on the lateral wall of the sheath of m. rectus abdominis in adult mice of the same strain. Neovascularization occurred in a dose-dependent manner. When purified by chromatography on Dowcx 1-x 2 and DEAE Sephadex columns, fractions eluted with 0.5 M NaCl showed strong ncovascularizing activity. On further purification by high performance liquid chromatography using TSK gel DEAE 2SW column, the fraction with a retention time nearly coincident with that of hyaluronic acid possessed high ncovascularizing activity. The activity of this fraction was markedly reduced when treated with streptococcal hyaluronidase. The present results suggest that glycosaminoglycans, especially a hyaluronic acid-like substance, are involved in ovarian neovascularization.
A Method for Estimating Glycine in the Presence of Excess Glutamate with o-Phthaldialdehyde
Authors: Lombardo Maria Elisa , Araujo Lidia Susana , Branca Andrea , Batlle Alcira M. del C.
Published: August 2018

We present a method to determine concentrations of glycine between 1 and 3 mM in the simultaneous presence of 25-100 mM glutamate, which is a modification of the procedure originally described by Klein and Linscr. Z. Physiol. Chem. 205,251 (1932). Glycine and glutamate react with 150 mM w-phthaldialdehyde, glycine is quantitatively con- verted into a colored o-phthaldialdehyde-glycine-glutamate complex. By recording the ab- sorbance of the complex at its maximum peak (around 540 nm). at 600 nm and 480 nm and applying a correction formula is possible to obtain a very good linear correlation when plot- ting the values of corrected absorbance versus the concentration of glycine. From these plots an extinction coefficient of 7.0 x 102 cm-1 m-1 was calculated for the complex. The method is highly reproducible and sensitive and solved the problem of glutamate interference when esti- mating low concentrations of glycine in mixture containing 10 to 50 times concentrations of the former aminoacid.
Solid State and Solution Structures of an Adenine Analogue of the Antiviral Acyclonucleoside 9-(1,3-Dihydroxy-2-propoxymethyl)guanine
Authors: Granzin Joachim , Saenger Wolfram
Published: August 2018

The title compound. 9-(1,3-dihydroxy-2-propoxymethyl)adenine (DHP-Ade). an analogue of the antiviral acyclonucleoside 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG), crystallizes in the monoclinic space group P21. with unit cell dimensions of a = 10.848(4), b = 8.765(3), c = 11.432(4) Å. β = 102.14(3)° . with two independent molecules in the asymmetric unit. The crystal structure of DHP-Ade was determined and compared with that for DHPG. The solution conformations of both acyclonucleosides were also determined with the aid of 1H and ,13C NMR spectroscopy. In the solid state the acyclic chain may adopt a “folded” form, i.e. gauche about the C(1′)-O(1′) bond (as in DHP-Ade), or an “extended” form (as in DHPG), results which corre- spond to the rotations about this bond in solution. A general discussion is presented of the conformations of the acyclic chains of various acyclonucleosides, from the antiviral 9-(2-hydroxyethoxymethyl)guanine (Acyclovir, ACV) through to 2′,3′-seco-nucleosides, both in the solid state and in solution, and the relevance of these to biological activities.
Photophysical and Photochemical Properties of 2,3-Dihydro-4(l H)-quinolinones. Part I. Fluorescence Properties
Authors: Bakalova Sn. , Biczók L. , Kavrakova I. , Bérces T.
Published: August 2018

Absorption spectra and fluorescence properties of 2,3-dihydro-4(1 H)-quinolinone derivatives were studied at room temperature in different solvents. It has been found that the fluorescence quantum yields and fluorescence decay times strongly depend on the molecular structure and solvent polarity. The character and the energy of excited states were determined by PPP and CNDO/S quantum-chemical calculations.
Asymmetrie Reconstitution of the Erythrocyte Anion Transport System in Vesicles of Different Curvature: Implications for the Shape of the Band 3 Protein
Authors: Lindenthal Sabine , Scheuring Uwe , Ruf Horst , Kojro Zbigniew , Petrasch Peter , Schubert Dieter
Published: August 2018

The anion transport protein of the human erythrocyte membrane, band 3, was solubilized and purified in solutions of the non-ionic detergent nonaethylene glycol lauryl ether and then reconstituted in spherical egg phosphatidylcholine bilayers as described earlier (U. Scheuring, K. Kollewe, W. Haase, and D. Schubert, J. Membrane Biol. 90, 123-135 (1986)). The resulting paucilamellar proteoliposom es of average diameter 70 nm were transformed into smaller vesicles by French press treatment and fractionated according to size by gel filtration. The smallest protein-containing liposomes obtained had diameters around 32 nm; still smaller vesicles were free of protein. All proteoliposome samples studied showed a rapid sulfate efflux which was sensitive to specific inhibitors of band 3-mediated anion exchange. In addition, the orientation of the transport protein in the vesicle membranes was found to be “right-side-out” in all samples. This suggests that the orientation of the protein in the vesicle membranes is dictated by the shape of the protein’s intramembrane domain and that this domain has the form of a truncated cone or pyramid
Elicitor Induction of Cytochrome P-450 Monooxygenases in Cell Suspension Cultures of Chickpea (Cicer arietinum L.) and Their Involvement in Pterocarpan Phytoalexin Biosynthesis
Authors: Gunia Werner , Hinderer Walter , Wittkampf Uta , Barz Wolfgang
Published: August 2018

A yeast glucan elicitor causes the accumulation of the pterocarpan phytoalexins medicarpin and maackiain in chickpea (Cicer arietinum) cell suspension cultures established from seeds. A cell culture line from a chickpea cultivar resistant against its main fungal pathogen Ascochyta rabiei accumulates large amounts (944 nm ol/g fr. wt.) whereas a cell culture line from a susceptible cultivar accumulates only low amounts (38 nm ol/g fr. wt.) of the phytoalexins. This is consistent with differential accumulation of pterocarpan phytoalexins in intact plants [1], The first reactions in the pterocarpan-specific branch of biosynthesis are hydroxylation of the isoflavone intermediate form ononetin in position 2′ or 3′, catalyzed by microsomal cytochrome P-450 monooxygenases. Upon elicitation form ononetin 2′-hydroxylase undergoes a strong transient induction in the cell suspension culture of the resistant cultivar, whereas in the cell culture from the susceptible cultivar it is only slightly induced. In both cell suspension cul­tures the induction of cinnamic acid 4-hydroxylase and of form ononetin 3′-hydroxylase does not show a clear correlation with phytoalexin accumulation. Experiments with different elici­tor concentrations confirm that formononetin 2′-hydroxylase is much more induced in cell cul­tures from the resistant cultivar than from the susceptible one. It is concluded that the massive difference in phytoalexin accumulation between cell suspension cultures from the resistant and susceptible cultivar is determined mainly by the differential induction of form ononetin 2′-hydroxylase activity.
On the Accessibility of Essential Tyrosines in Isolated and Activated Chloroplast H+
-ATPase
Authors: Bickel-Sandkötter Susanne , Esser Kordula , Horbach Martina
Published: August 2018

The addition of 7-chloro-4-nitrobenzofurazan to isolated and activated CF1, creates a completely changed binding stoichiometry and subunit-distribution of bound modifier in contrast to the binding pattern in not-activated CF1. The activation of CF1, by dithiothreitol and heat results in the accessibility of three additional tyrosines in β-subunits and one additional tyro­ sine in α-subunits. Binding of pyridoxalphosphate to lysine in the active state suppresses the accessibility of the additional tyrosines, suggesting that PLP inactivates the ATPase by induc­ing a conformational change. Furthermore, two NBD -molecules are bound to γ-subunits when CF1, is activated. These two molecules may be bound to sulfhydryl groups of cysteines which become accessible to NBD after activation.
Characterization of Reaction Center-B875 Complex of Rhodocyclus gelatinosus: QB Site Properties Derived from Reconstitution Experiments
Authors: Agalidis I. , Rivas E. , Reiss-Husson F.
Published: August 2018

Purified reaction center-B875 pigment-protein complex isolated from Rc. gelatinosus (I. Agalidis, E. Rivas, and F. Reiss-Husson, Photosynth. Res. 23, 249 - 255 (1990)) was further characterized. In the chromatophores, the quinone content was shown to be 6 menaquinones 8 and 16 ubiquinones 8 per reaction center, indicating that the pool contained both quinone types. Besides the primary (MK8) and secondary (UQ8 ) electron acceptors of the reaction cen­ter, the complex contains residual quinones from the membrane pool (about 3 MK8 and 5 UQ8) probably associated with the phospholipids. Apparent particle weight of the complex including bound detergent was 520 ± 46 kDa.

The secondary quinone QB was partially removed from the RC by treatment with 2 -3 % octaethyleneglycol dodecyl ether and 3 -4 mᴍ orthophenanthroline. Reconstitution experi­ments showed that UQ6, UQ9 and UQ10 could replace QB but that MK8 and MK9 could not. It was concluded that QB site has a clear specificity towards ubiquinone binding.
Product Release is Not the Rate-Limiting Step during Cytochalasin B-Induced ATPase Activity of Monomeric Actin
Authors: Dancker Peter , Hess Lore , Ritter Karl
Published: August 2018

Under conditions where cytochalasin B induces ATPase activity of monomeric actin (0.3 mᴍ MgCl2, 1 mᴍ EGTA , 30 (μᴍ cytochalasin B, 1 mᴍ ATP) the rate constant of the ex­change of actin-bound ε-ATP for free ATP is about 4 -6 times faster than steady state ATPase activity. When a stoichiometric ATP -actin complex is extracted with PCA (single turnover ex­periment) the apparent rate constant of Pi generation is not faster than steady state ATPase activity. -The experiments suggest that the hydrolysis of actin-bound ATP and not the subse­quent release of hydrolysis products is rate-limiting during cytochalasin-induced ATPase activi­ty of actin.
The Inhibition of Glutathione Reductase by Quinones
Authors: Bironaitė Daiva A. , Čėnas Narimantas K. , Kulys Juozas J. , Medentsev Alexander G. , Akimenko Vasiliy K.
Published: August 2018

Fully substituted quinones including some naturally occurring oxyquinones acted as inhibitors of yeast glutathione reductase (EC 1.6.4.2). They were competitive, mixed or uncompetitive inhibitors for NADPH , possessing Ki in the range of 1-200 μM and uncompetitive inhibitors for glutathione. Rhein (4,5-dioxy-9,10-anthraquinone- 2-carbonic acid) and 9,10-phenanthrenequinone were the most effective inhibitors. It is concluded that certain quinones can bind to the NADP(H )-binding site and to the heteroaromatics binding site at the interface domain (P. A. Karplus, E. F. Pai, and G. E. Schulz, Eur. J. Biochem. 178, 693-703 (1989)) of the enzyme.
Isolierung und spektroskopische Charakterisierung des Pyoverdin-Chromophors sowie seines 5-Hydroxy-Analogen [1] / Isolation and Spectroscopic Characterization of the Pyoverdin Chromophore and of Its 5-Hydroxy Analogue [1]
Authors: Michels J. , Benoni H. , Briskot G. , Lex J. , Schmickler H. , Taraz K. , Budzikiewicz H. , Korth H. , Pulverer G.
Published: August 2018

The isolation of the common chromophore of the pyoverdins isolated from iron-deficient cultures of fluorescent Pseudomonas strains and of its 5-hydroxy analogue as well as the spectroscopic characterization of the two compounds is described.
Inactivation of Photosynthetic O2 Evolution in the Cyanobacterium Anacystis nidulans PCC 6301: Influence of Nitrogen Metabolites and Divalent Cation Concentration
Authors: Wälzlein Gudrun , Pistorius Elfriede K.
Published: August 2018

An investigation about the in vivo inactivation of photosynthetic water oxidation has been carried out in the cyanobacterium Anacystis nidulans (Synechococcus PCC 6301). Photosystem II and photosystem I activity as well as the relative amount of the D1 and manganese stabilizing peptide of photosystem II were determined after growing the cells in nutrient media with variations in the nitrogen source and the concentration of the major divalent cations (Mg2+ and Ca2+). The results show a rapid inactivation of water oxidation in A. nidulans in response to nitrogen deficiency and in response to reduced Mg2+ and Ca2+ concentrations. The inactivation of water oxidation observed under divalent cation deficiency could be greatly accelerated when L-amino acids instead of ammonia or nitrate were used as nitrogen source. Under these conditions inactivation of water oxidation correlated with a rapid loss of D1 and with a slower loss of the manganese stabilizing peptide from photosystem II. A possible regulation of the photosystem II activity in A. nidulans by nitrogen metabolites is suggested.
Semiochemicals of the Scarabaeinae, III: Identification of the Attractant for the Dung Beetle Pachylomerus femoralis in the Fruit of the Spineless Monkey Orange Tree, Strychnos madagascariensis
Authors: Burger B. V. , Petersen W. G. B.
Published: August 2018

Following the observation that the non-ball-rolling dung beetle Pachylomerus femoralis (Kirby) rolled the flesh-covered seeds from the fruit of the spineless monkey orange tree, Strychnos madagascariensis Poiret, an investigation into the chemical attractants of this fruit was made. Using headspace gas chromatography with electroantennographic and flame ionization detection in parallel, followed by GC-MS analysis, 1-butanol, methyl butanoate, ethyl 2-methylpropanoate, ethyl butanoate, butyl ethanoate, ethyl 2-methylbutanoate, propyl butanoate, butyl propanoate, methyl hexanoate, butyl 2-methylpropanoate, and butyl butanoate were identified as the constituents of the attractant. It was found that P. femoralis beetles were attracted to a mixture of the synthetic compounds about as strongly as to the fresh fruit. The beetles were also equally attracted to the fruit and to horse dung in areas where ripe fruit was not available. In areas permeated with the smell of the ripe fruit the horse dung retained its attractiveness, whereas no beetles were caught in traps baited with fruit.
Occurrence of Jasmonic Acid in the Red Alga Gelidium latifolium
Authors: Krupina Marina V. , Dathe Wilfried
Published: August 2018

The growth regulators (-)-jasmonic acid (JA) and its 7-isom er were identified by GC-MS in the red alga Gelidium latifolium. The ratio of JA:7-iso-JA was approximately 93:7. The endogenous level amounted to 0.7 μg JA/g fresh weight.
Synchronized Activity in the Insect Brain
Authors: Kirschfeld K.
Published: August 2018

Among the electrical signals that can be recorded from the vertebrate cortex are voltage oscillations in the frequency range 40-70 Hz (γ-waves). For some years the possible role of these waves as information carriers has been under discussion. Relatively high-level functions such as “feature linking” have been proposed for them, and they have even been considered in the context of phenomena such as “awareness” and “consciousness” [1]. The insect brain exhibits high-frequency (hf) oscillations in the range of 100-200 Hz that have much in common with the γ-waves, but their function is interpreted differently.
Prenylated Flavanone Production in Callus Cultures of Sophoraßavescens var. angustifolia
Authors: Yamamoto Hirobumi , Kawai Sumiko , Mayumi Junko , Tanaka Toshiyuki , Iinuma Munekazu , Mizuno Mizuo
Published: August 2018

Callus cultures of Sophora favescens var. angustifolia established on Murashige-Skoog medium containing 1 μм 2,4-dichlorophenoxyacetic acid and 1 μм kinetin produced the prenylated flavanones (2S)-5,7,2′,4′-tetrahydroxy-8-lavandulylflavanone (sophoraflavanone G) and (25)-7,2′,4′-trihydroxy-8-lavandulylflavanone (lehmannin). In addition, maackiain and its 3-O-β-glucoside (trifolirhizin) were also produced in the callus. Up on transfer to White’s medium or M9 medium, the content of prenylated flavanones, in particular lehmannin, was increased, whereas that of pterocarpans was decreased. Time-course experiments indicated that the production of pterocarpans was closely related with cell growth. On the other hand, an inverse relationship existed between cell growth and the production of prenylated flavanones.
Occurrence of (-)-Geosm in and Other Terpenoids in an Axenic Culture of the Liverwort Symphyogyna brongniartii
Authors: Spörle Jörg , Becker Hans , Allen Noris Salazar , Gupta Mahabir P.
Published: August 2018

An axenic culture of Symphyogyna brongniartii has been initiated from spores on modified Benecke medium. Growth was best on Gam borg B5 medium with 0.3% sucrose, with a doubling time of 36 days. The culture produced the same terpenoids as plants growing in their natural habitat, perrottetianal A being the major constituent. Also found were bicyclogermacrene, β-barbatene, δ-selinene, β-cubebene, spathulenol, and (-)-geosm in . The latter compound was hitherto only known from microorganisms. Synthesis rate of terpenoids during the passage period and quantitative differences in terpenoid production on different mineral media were investigated.
Cataract Induction by 1,2-Naphthoquinone I. Studies on the Redox Properties of Bovine Lens Proteins
Authors: Kleber E. , Kroner R. , Elstner E. F.
Published: August 2018

Conditions of oxidative stress may lead to cataract formation. Reaction of certain flavoproteins, the NADH :oxidoreductases, with different quinones is well known to form hydrogenperoxide. This reaction was investigated to get more information on cataract induction by naphthalene and its quinone metabolites. Protein extracts from bovine lens cortex exhibit “diaphorase” activity, indicated as dye reduction in the presence of NADH and dichlorophenol-indophenol (DCPIP) or ferricyanide. Different redox cycling com pounds are shown to be active in this “diaphorase” reaction by lens protein extract (LCE): Oxygen consumption can be detected in the presence of pyrroloquinoline quinone and juglone whereas 1,4-naphthoquinone, menadione and paraquat are no redox cyclists in this flavoprotein catalyzed reaction.
Notes: Partial Characterization of anti-H L A Class II Antibodies Isolated by Aid of Sepharose-Peptide Immunoadsorbents
Authors: Chersi Alberto , Morganti-Kossmann Maria Cristina
Published: August 2018

Synthetic peptides selected from HLA-DQ and HLADP glycoproteins were coupled to Sepharose, and used for the isolation of anti-HLA Class II antibodies from the immune sera of rabbits immunized with human lymphoblastoid cells expressing Class II antigens.

Antibodies from early and late bleedings displayed remarkable differences in affinity for peptides and for soluble membrane proteins: these differences might be due to an early immune response directed preferentially against surface linear determinants, and to a late response to assembled (discontinuous) sites.

The possibility that such antibodies might be used for the identification of amino acid stretches involved in the formation of the same assembled determinant is considered.
Ions Modify The Strength Of Interaction Of Diquat And Paraquat With Some Proteins And Cellulose
Authors: Cserháti Tibor , Szigeti Zoltán
Published: August 2018

The interaction of the bipyridylium herbicides diquat and paraquat with the proteins gliadin and human serum album in (HSA) as well as with cellulose and the effect of various ions on the strength of interaction were studied by charge-transfer chromatography. Both compound showed very similar behaviour. The ions decreased in each case the strength of interaction, the effect depended nonlinearly on the ion concentration and was of saturation character. Gliadin showed the weakest interaction. HSA binds the bipyridylium com pounds in an ion-dependent manner, the strength of interaction is higher than that of cellulose at higher ion concentration. This finding indicates an ion-mediated interaction of unknown character between the bipyridylium herbicides and HSA
Shear Deformation Of The Spherical Shell Acted On By An External Alternating Electric Field: Possible Applications To Cell Deformation Experiments
Authors: Pawlowski Piotr , Fikus Magdalena
Published: August 2018

Shape deformation of the thin, area non-compressible spherical shell separating two different media, subjected to an external, alternating, homogeneous electric field is considered. The function relating shape deformation of the shell to the shear stress in its plane is presented. Shear stress develops as a result of Maxwell stress acting on both shell surfaces. All media are considered as lossy. The theoretical model predicts that the shear stress reaches its maximal value at the shell “equator” in relation to the field direction. The magnitude of the shear stress depends on the strength and frequency of the electric field, on the geometric parameters of the shell, and on the electric parameters of the system studied. The foregoing was applied to an analysis of cell deformation, e.g., an erythrocyte in an electric field. The analysis predicts that the maximal shear stress in the membrane develops at field frequencies close tof = 107 Hz. This is comparable to the electrocompression stress of the same membrane, maximal at the cell “pole”. At lower frequencies, compression predominates over shear stress
Zwei Pyoverdine aus Pseudomonas aeruginosa R. / Two Pyoverdins from Pseudomonas aeruginosa R
Authors: Gipp S. , Hahn J. , Taraz K. , Budzikiewicz H.
Published: August 2018

The structure elucidation of two pyoverdins from the strain R. of Pseudomonas aeruginosa is described.
Activity of Photosystem II Herbicides Is Related with Their Residence Times at the D 1 Protein
Authors: Naber J. Dirk , van Rensen Jack J. S.
Published: August 2018

The reversible binding kinetics of atrazine, diuron and ioxynil were measured via their binding and release parameters during steady state inhibition of electron transport. The parameters were determined in isolated chloroplasts of peas and of triazine-resistant and -susceptible bio­ types of Chenopodium album using a kinetic model. This model is based on the flash-induced oxygen evolution patterns of isolated broken chloroplasts.

It was found that the binding parameters were always significantly higher in the case of an oxidized acceptor quinone complex as compared with a semi-reduced complex. Triazine resistance seems to originate from a significant increase of the release kinetics. The release parameters could be used to calculate the residence times of the herbicides at the D 1 protein. The values of these residence times were always much higher for the herbicides than for Q B; this explains the inhibition of electron transport. The only exception was the residence time of atrazine in the resistant biotype, where the value was close to that of Q B.

It is concluded that the “on” kinetics of a compound to its binding environment at the D 1 protein are determined principally by the accessibility of the niche to the compound. The differences in activity between herbicides are mainly due to variations in the release kinetics.
Activities and Regulation of Enzymes of Carbohydrate Metabolism in Spruce ( Picea abies)
Authors: Boll Meinrad
Published: August 2018

Activities of the glycolytic enzymes were determined in seedlings, callus cultures and cell sus­ pension cultures of spruce (Picea abies) (L.) (Karst). The rate-limiting enzymes of the pathway were the hexokinases, ATP: phosphofructo-kinase, fructose-1,6-bisphosphatase and pyruvate kinase. Two phosphofructokinases were found: ATP : fructose-6-phosphate 1-phosphotransferase (PFK) and pyrophosphate :fructose-6-phosphate 1-phosphotransferase (PFP). In the presence of its activator fructose-2,6-bisphos-phate, PFP had a 4 -5-fold higher specific activity than PFK. PFP could be activated about 20-fold by fructose-2,6-bisphosphate at saturating concentrations of the substrates (fructose-6-phosphate and pyrophosphate). The increase of Vmax was accompanied by a strong increase in the apparent affinity of the enzyme for the substrates. Km for fructose-6-phosphate and pyrophosphate was 0.44 mM and 24 μM, respectively. Ka for fructose-2,6-bisphosphate was 24 nM.

In seedlings, specific activity of the glycolytic enzymes was 30-300 percent higher in the hypocotyls, except for fructose-1,6-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase, their activity being 100-150percent higher in the cotyledons, This distribution remained unchanged during periods of 2 -16 weeks of cultivation of the seedlings.

In callus cultures and in cell suspension cultures, grown mixotrophically with different car­ bohydrates, all enzymes were between 1-and 7-fold higher than in autotrophically grown seed­ lings. Incubation of seedlings in mineral salt mixture containing a carbohydrate resulted in a rapid coordinate increase of the activities to the levels of callus-or cell suspension cultures. This induction required a carbohydrate and oxygen. During prolonged cultivation of cell suspension cultures, when carbohydrate became limiting, activity of the enzymes slowly declined.
Contrasting pH-Optima of Light-Driven O2-and H2O2-Reduction in Spinach Chloroplasts as Measured via Chlorophyll Fluorescence Quenching
Authors: Schreiber Ulrich , Reising Heinz , Neubauer Christian
Published: August 2018

Quenching analysis of chlorophyll fluorescence by the saturation pulse method is used to investigate the pH-dependency of O2-dependent electron flow in intact spinach chloroplasts with high ascorbate peroxidase activity. When carboxylase/oxygenase activity is blocked, pho­tochemical and non-photochemical quenching are initially low and increase with illumination time. Quenching shows a pH-optimum around pH 6.5, but only when ΔpH-formation is al­ lowed. It is suggested that overall O2-dependent electron flow involves two major components, namely O2-reduction (Mehlerreaction) and reduction of the H2O2 formed in the Mehlerreaction, involving enzymic activity of ascorbate peroxidase and monodehydroascorbate reductase. The separated pH-dependencies of light driven O2-reduction (presence of KCN) and of H2O2-reduction (anaerobic conditions) reveal contrasting pH-optima around pH 5 and 8.5, respectively. Energy-dependent, dark relaxable non-photochemical quenching is not observed with O2-reduction but with H2O2-reduction, and only at pH-values above 6.5. The relevance of these findings with respect to regulation of photosynthetic electron flow is discussed. It is suggested that upon limitation of assimilatory electron flow O2-dependent non-assimilatory flow is responsible for ΔpH-formation, by which it is autocatalytically stimulated. It is proposed that this autocatalytical reaction sequence is the basis of the so-called “Kautsky effect” of chlorophyll fluorescence induction.
Propagation of Voltage Transients in Arborized Neurites of Retzius Cells of the Leech in Culture
Authors: Fromherz Peter , Vetter Thomas
Published: August 2018

Propagation of electrical signals is studied in Retzius cells of the leech in culture using voltage-sensitive fluorescent dyes at a spatial resolution of 8 × 8 μm2 and 14×14 μm2 and at a sam pling interval of 0.12 ms. The neurons are stimulated by a microelectrode impaled in the soma. Action potentials of a halfwidth of 2 -3 ms are triggered close to the end of the primary neurite dissociated from the leech. They propagate back to the soma at invariant halfwidth at a veloci­ ty of 50-230 μm/ms. They pervade extended arborized secondary neurites which are grown on extracellular matrix protein. Their width is enhanced up to a factor two. The velocity is around 100-150 μm/ms such that delays up to 3.5 ms are observed. Accordingly the neuritic trees are not isopotential. The features of propagation are found to be incompatible with passive spread.
Surface Structure and Chemical Composition of Epicuticular Waxes during Leaf Development of Tilia tomentosa Moench
Authors: Gülz Paul-Gerhard , Prasad R. B. N. , Müller Edith
Published: August 2018

The very young leaflets of silver lime trees (Tilia tomtentosa), just unfolding from buds, con ­ tained a continuous wax layer without any wax sculptures. The wax on young leaves is quite different in yield and composition than that of mature leaves. After unfolding of leaves a very dynamic biosynthesis of most wax lipids was started. Fifteen days after leaf unfolding the de novo biosynthesis of β-amyrenyl acetate and later on of aldehydes could be detected for the first time. The biosynthesis of wax components in silver lime leaves was finished at the end of June and the wax remained nearly constant in amount and composition during the remaining season. At the same time, when β-amyrenyl acetate was found for the first time, wax sculptures were observed in silver lime leaf waxes coming out of the continuous wax layer, exclusively on the upper leaf side. These wax sculptures increased in quantity in the next weeks and resulted in a crystalloid shape of most solitaire quadrangular rodlets. These crystals were remained all over the season and were formed from β-amyrenyl acetate, the dominating main wax compo­nent {ca. 49% wax).
Sequence Analysis of the D1 and D2 Reaction Center Proteins of Photosystem II
Authors: Svensson Bengt , Vass Imre , Styring Stenbjörn
Published: August 2018

A compilation of 38 sequences for the D1 and 15 sequences for the D 2 reaction center pro­teins of photosystem II is presented. The sequences have been compared and a similarity index that takes into account the degree of conservation and the quality of the changes in each posi­tion has been calculated. The similarity index is used to identify and describe functionally im­portant domains in the D1 / D2 heterodimer. Comparative hydropathy plot are presented for the aminoacid sidechains that constitute the binding domain of the tyrosine radicals, TyrZ and TyrD, in photosystem II. The structure around TyrZ is more hydrophilic than the structure around TyrD. The hydrophilic residues are clustered in the part of the binding pocket for TyrZ that is turned towards the lumenal side of the thylakoid membrane. Most prominent is the presence of two conserved carboxylic am inoacids, D1-Asp 170 and D1-Glu 189. Their respec­tive carboxyl-groups come close in space and are proposed to constitute a metal binding site together with D1-Gln 165. The distance between the proposed metal binding site and the cen­ter of the ring of TyrZ is approximately 7Å . The cavity that constitutes the binding site for TyrD is composed of residues from the D 2 protein. Its character is more hydrophobic than the TyrZ site and the environment around TyrD lacks the cluster of putative metal binding side­-chains.
Glutathione S-Transferase Activity in Nontreated and CGA-154281- Treated Maize Shoots
Authors: Dean John V. , Gronwald John W. , Anderson Michael P.
Published: August 2018

Fast protein liquid chromatography (anion exchange) was used to separate glutathione S-transferase isozymes in nontreated etiolated maize shoots and those treated with the herbi­cide safener CGA -1542814-(dichloroacetyl)-3,4-dihydro-3-methyl-2 H-1 ,4-benzoxazine. Non­treated shoots contained isozymes active with the following substrates: trans-cinnamic acid (1 isozyme), atrazine (3 isozymes), 1-chloro-2,4-dinitrobenzene (1 isozyme), metolachlor (2 isozymes) and the sulfoxide derivative of S-ethyl dipropylcarbamothioate (2 isozymes). Pre­treatment of shoots with the safener CGA -154281 (1 μM) had no effect on the activity of the isozymes selective for trans-cinnamic acid and atrazine but increased the activity of the constitutively-expressed isozymes that exhibit activity with 1-chloro-2,4-dinitrobenzene, metola­chlor and the sulfoxide derivative of S-ethyl dipropylcarbamothioate. The safener pretreat­ment also caused the appearance of one new isozyme active with 1-chloro-2,4-dinitrobenzene and one new isozyme active with metolachlor. The results illustrate the complexity of gluta­thione S-transferase activity in etiolated maize shoots, and the selective enhancement of gluta­thione S-transferase isozymes by the safener CGA -154281.
Enhanced Inducibility of Antioxidant Systems in a Nicotiana tabacum L. Biotype Results in Acifluorfen Resistance
Authors: Gullner Gábor , Kőmíves Tamás , Király Lóránt
Published: August 2018

Levels of non-protein thiols (mostly glutathione, GSH), ascorbic acid (AA), and activities of the enzymes ascorbate peroxidase (AP), glutathione reductase (GR) and GSH S-transferase (GST) were determined in cell-free leaf extracts of acifluorfen-resistant and -sensitive tobacco plants. These parameters were examined also in detached leaves of the above plants exposed to acifluorfen stress. In leaves of untreated plants the AA content was by 40% higher in the resist­ ant biotype as compared to the sensitive ones, but the levels of GSH, AP, GR, and GST did not differ significantly in the two biotypes. However, in the resistant leaves stressed by aci­fluorfen the activity of AP readily increased while in the sensitive leaves it did not change. The levels of GSH and the activities of GR and GST markedly increased in both biotypes after acifluorfen stress, but the induction in the resistant leaves was consistently stronger in each case. The AA contents were increased equally in both biotypes. These parameters were much less affected by paraquat stress. The only significant changes were observed at low concentra­tions of this herbicide (8 x 10-9 м): when the thiol content and the activity of GST increased in the resistant leaves.

Enhanced inducibility of antioxidant systems seems to be involved in resistance of tobacco to acifluorfen stress.
Naphthalic Anhydride Induces Imazethapyr Metabolism and Cytochrome P-450 Activity in Maize
Authors: Barrett Michael , Maxson Julie M.
Published: August 2018

Naphthalic anhydride is a seed-applied herbicide safener which reduces the toxicity of ima­zethapyr, an imidazolinone herbicide, to maize (Zea mays L.). Protection of maize from ima­zethapyr was dependent on the amount of naphthalic anhydride applied to the seed. Metabo­lism of imazethapyr by maize roots and shoots was increased by exposure of the roots to a solution containing naphthalic anhydride. Increased imazethapyr metabolism due to naph­thalic anhydride treatment of roots was observed within 4 h following safener exposure. Nitro­gen, carbon monoxide and tetcyclacis inhibited imazethapyr metabolism in maize coleoptiles grown from naphthalic anhydride treated seed. This suggests that imazethapyr is metabolized by a cytochrome P-450 monooxygenase.

Naphthalic anhydride application to maize seed increased the level of cytochrome P-450 in the seedling shoots. Microsomes isolated from coleoptiles grown from naphthalic anhydride treated seed, but not untreated seed, converted bentazon to hydroxy-bentazon but did not me­ tabolize imazethapyr. Protection of maize from imazethapyr damage by naphthalic anhydride is due to a safener-induced higher rate of imazethapyr metabolism associated with elevated cytochrome P-450 levels. However, this was not demonstrated in vitro for imazethapyr.
Influence of Safeners on the in vivo and in vitro Metabolism of Bentazon and Metolachlor by Grain Sorghum Shoots: a Preliminary Report
Authors: Moreland Donald E. , Corbin Frederick T.
Published: August 2018

Metabolism of bentazon and metolachlor by excised shoots and a microsomal fraction iso­lated from the shoots, of 3-day-old, dark-grown, grain sorghum (Sorghum bicolor cv. Funk G 522 DR) seedlings was studied. The effects of seed treatments, on the subsequent metabo­lism of the herbicides, with the safeners naphthalic anhydride, oxabetrinil, and CGA 133205 were compared against surface-sterilization and Captan-treatments. Bentazon was aryl hydroxylated in both in vivo and in vitro studies with the hydroxylated derivative undergoing glycosylation only under in vivo conditions. Both shoots and microsomes isolated from shoots of safener-treated seed showed enhanced metabolism of bentazon relative to the controls. In­ hibition by tetcyclacis, a potent inhibitor of plant cytochrome P-450 monooxygenases, in both the in vivo and in vitro studies, and a requirement for NADPH in the in vitro studies suggested that the formation of hydroxybentazon was mediated by a cytochrome P-450 monooxygenase. Metolachlor was metabolized to polar material and O-desmethylmetolachlor under in vivo conditions. Only the demethylated product was formed in vitro. Shoots isolated from safener-treated seed showed enhanced formation of polar com pounds which were assumed to have arisen from conjugation with glutathione. Tetcyclacis did not affect the formation of the polar components. However, the formation of O-desmethylmetolachlor was depressed in the shoots excised from safener-treated seed under both in vivo and in vitro conditions. Tetcyclacis completely prevented formation of the demethylated metabolite. Hence, formation of this meta­bolite is considered to be P-450 mediated. The differential response obtained with the safeners, i.e., stimulation of aryl hydroxylation of bentazon and depression of metolachlor demethylation, suggests that the reactions are probably catalyzed by different cytochrome P-450 mono­oxygenases.
Antagonistic Interactions of Mefenacet with Inhibitors of Monooxygenases
Authors: Fedtke Carl
Published: August 2018

The monooxygenase suicide inhibitor piperonyl butoxide (PBO) antagonizes the inhibitory activity of the herbicide mefenacet in a root regeneration test system with etiolated cut oat stems. When studying the behaviour of [14C]mefenacet [2-(2-benzothiazolyloxy)-N-methyl-N-phenylacetamide] in cut oat stems that had been pretreated with PBO for 24 h after cutting, an increased rate of uptake and increased concentrations of mefenacet in the tissue were found after PBO as compared to water pretreatment. Increased uptake rates and increased rates of metabolism after PBO pretreatment, supposedly by increased monooxygenation, were also observed with the substrates diuron, 2,4-D and cinnamic acid. Mefenacet induced the same responses as PBO in all systems.

The similar actions of mefenacet and PBO are interpreted to suggest that mefenacet might interfere with monooxygenase enzymes. Similar responses, i.e. stimulation of monooxygena­tion of suitable substrates, have been reported for herbicide safeners. An environmentally con­trolled regulatory response system is suggested to be triggered by the different classes of compounds, mefenacet and similar herbicides, monooxygenase inhibitors, and safeners, and to re­spond with increased enzyme activities in the monooxygenase and glutathione detoxification pathways.
Iridoid Glueosides from Plantago altissima L., Plantago lanceolata L., Plantago atrata Hoppe and Plantago argentea Chaix.
Authors: Handjieva Nedjalka , Saadi Houcine , Evstatieva Ljubka
Published: August 2018

Plantago altissima L., Plantago lanceolata L., Plantago atrata Hoppe and Plantago argentea Chaix. were examined for iridoids. In all four species aucubin and catalpol were found. Globularin and methyl ester of the desacetylasperulosidic acid were isolated for the first time from Plantaginaceae plants (P. altissima and P. lan­ceolata). Asperuloside was found for the first time in P. altissima as well as dihydroaucubin in P. atrata.
Compositions of Bud and Leaf Exudates of Some Populus Species Compared
Authors: Greenaway W.
Published: August 2018

Bud and leaf exudates from Populus alba, P. balsamifera, P. nigra and P. tremuloides were analyzed by gas chromatography/mass spectrometry and their components were identified. For three of the four species, P. alba, P. balsamifera and P. nigra, the bud and leaf exudates were similar within each species, though there were marked differences between species. Bud and leaf exudates of P. alba contained only hydrocarbons, those of P. balsamifera contained primarily dihydrochalcones and those of P. nigra contained primarily caffeic acid esters. Bud and leaf exudates of P. tremuloides were different both from each other and from those of the other three species. Bud exudate of P. tremuloides contained a range of phenolic compounds which were largely lacking from the leaf exudate.
Superoxide Dismutase and Sulfite Oxidation
Authors: Miszalski Z. , Ziegler H.
Published: August 2018

50 U SOD in 1 ml or 10 mᴍ DDTC do not much change sulfite oxidation due to the free radicals procuding system xanthin-xanthin oxidase. Sulfite oxidation due to the activity of this free radicals producing system proceeds probably as the univalent oxidation of sulfite. The role of SOD in SO, resistance mechanism in plants and the role of DDTCas SO2 oxidation effect stimulator is discussed.
Modulation by Ryanodine of Active Calcium Loading and Caffeine Induced Calcium Release of Heavy Sarcoplasmic Reticulum Vesicles
Authors: Hasselbach Wilhelm , Migala Andrea
Published: August 2018

The effect of ATP on the calcium release channel in heavy sarcoplasmic reticulum vesicles modulated by ryanodine has been analyzed by monitoring active calcium uptake and caffeine induced calcium release under near physiological conditions. Native as well as ryanodine reacted vesicles display a complex time course of calcium uptake resulting in nearly complete exhaustion of medium calcium when ATP in combination with an ATP-regenerating system, in contrast to ATP alone, or dinitrophenyl phosphate, were used to support calcium uptake. Applying of dinitrophenyl phosphate as energy yielding substrate, not affecting channel activity, allowed to estimate the fraction of light vesicles devoided of calcium channels contam inating the heavy preparation as the fraction that stores calcium after the preparation has been treated with channel opening, low concentrations of ryanodine (1 μᴍ). Calcium uptake by contaminant light vesicles (25%) cannot account for calcium storage, as well as, abolition of caffeine induced calcium release of ryanodine treated heavy vesicles. Calcium uptake of native and ryanodine treated vesicles is accompanied by the uptake of equivalent amounts of inorganic phosphate arising from ATP hydrolysis indicating that calcium is mainly stored as calcium phosphate. The momentary capability of the preparation to accumulate calcium was measured by activating calcium uptake during the calcium storage period with 0.2 mᴍ 45CaCl2 and 4 mᴍ phosphate at short time intervals. A significant increase of the momentary uptake activity with time was observed being more pronounced for ryanodine treated than for native vesicles indicating that under regenerating conditions, ATP can induce closing of the native and even more effectively of the ryanodine modified calcium release channels.
Phenolic Compounds from Lactuca viminea L.
Authors: Terencio Mari Carmen , Sanz María Jesús , Fonseca María Luisa , Máñez Salvador , Ríos José Luis
Published: August 2018

The aerial part of Lactuca viminea L. was examined for the presence of phenolic compounds. Six different flavonoids were isolated and identified by UV spectra, TLC, HPLCDAD , 1H NMR and 13C NMR. They were identified as apigenin, luteolin, quercetin, luteolin-7-O-glucoside, quercetin-3-O-glucoside and luteolin-7-O-glucuronide-6″methyl ester. Three phenolic acids were also detected: caffeic, ferulic and chlorogenic acid.
Composition of Iridals, Unusual Triterpenoids from Sword-Lilies, and the Seasonal Dependence of Their Content in Various Parts of Different Iris Species
Authors: Marner Franz-Josef , Kerp Bianca
Published: August 2018

The composition of iridals, new triterpenoids from sword-lilies, and their fatty acid esters in roots, rhizomes and leaves of I. germanica Linn., I. pseudacorus Linn, and two different varieties of I. pallida Lam. was determined. Quantitative analysis of their total content in the various parts of the plants in the course of the year showed specific seasonal changes in rhizomes and leaves. Based on these results the possible significance of these compounds for the plants is discussed.
Seasonal Variation In The Composition Of Epicuticular Waxes Of Quevcus Robur Leaves
Authors: Gülz P.-G. , Müller E.
Published: August 2018

The epicuticular leaf waxes of Quercus robur were analyzed continuously over a two years vegetation period with preparation every week from April to November. The folded leaflets in buds have waxes quite different in yield and composition from those of mature leaves. They contain homologous series of hydrocarbons, wax esters, primary alcohols, fatty acids and triterpenoids from the beginning, but not aldehydes. After leaf unfolding a dynamic biosynthesis of alcohols, aldehydes and fatty acids is observed in May and June. Wax content is doubled per dry weight or in cm2 leaf surface area and 80-fold per one leaf in that time. During leaf development tetracosanol becomes the dominant epicuticular wax component comprising ca. 40% of the wax. In both years of the study a reactivation of wax ester biosynthesis is observed in October and November. Esters with chain length C36 and C38 increased particularly. From July to November the wax composition remained nearly constant within mean values and their standard deviations. Within the two years studied most values concerning wax composition are reproducible and are therefore genetically determined. In spring the growing processes are influenced by climatic factors