bluuebunny/crossref_metadata_2025 huggingface dataset:
Phytochemische Untersuchungen an westeuropäischen Lasallia-Arten Phytochemical / Investigations on Western European Lasallia Species
Authors: Posner Birgit , Feige Guido Benno , Huneck Siegfried
Published: August 2018

The secondary product pattern of 38 specimens of Lasallia brigantium (Zsch.) Llano, L. hispanica (Frey) Sancho & Crespo and L. pustulata (L.) Merat were investigated by HPLC. A c­ cording to previous publications gyrophoric acid, lecanoric acid and umbilicaric acid were detected. Additionally two further unknown depsides were found. The presence of the anthraquinone skyrin, new to Lasallia, was shown for L. hispanica and L. pustulata. Skyrin is not equally distributed within the thalli but mainly concentrated in the umbilicus. In L. hispanica skyrin is located in the epihymenium, too. A correlation between secondary product pattern and thallus size or light supply does not exist.
Antifungal Antibiotics from Calcarisporium thermophilum: A New Source of 15-Azahomosterol Derivatives
Authors: Chrisp Paul , Dewick Paul M. , Boyle F. Tom
Published: August 2018

Two antifungal metabolites isolated from Calcarisporium thermophilum were identified as 15-azahom osterols related to the compounds previously isolated from Geotrichum Jlavo-brun-neum. By full spectral comparison with authentic 15-aza-24-methylene-D-homocholesta-8,14-dien-3 β-ol (A 25822 B) from G. flavo-brunneum, the Calcarisporium metabolites were characterized as the 4a-m ethyl-and 4,4-dimethyl-analogues of A 25822 B. Several minor members of the series were also detected, and tentatively identified by MS analysis. The 15-azahom osterols exhibited good antifungal activity towards Candida parapsiliosis, though the activities were somewhat lower than that of the 4-demethyl derivative A 25822 B. Calcarisporium thermophi­lum is the second microorganism known to synthesize these unusual 15-azahomosterol deriva­tives.
A Photosynthetic Antenna System which Contains a Protein-Free Chromophore Aggregate
Authors: Holzwarth Alfred R. , Gnebenow Kai , Gnebenow Kai , Schaffner Kurt
Published: August 2018

The interior of chlorosomes, the main antenna system of the photosynthesizing bacterium Chloroßexus aurantiacus, is shown to contain no proteins in a fixed ratio to BChl c and in amounts that could be significant of direct chromophore-protein complexes. This excludes non-covalent chromophore-protein complexing -that has so far been found in all other antennae -as the main organizational principle of the interior architecture for chlorosom es of chlorophyll C. aurantiacus. Rather, these antennae constitute the first case of a chromophore-chromophore aggregate functioning as a photosynthetic light harvesting system.
Phosphohydrolase Activities in Developing and Mature Dental Tissues
Authors: Warth Edda , Jeck Reinhard
Published: August 2018

In the course of the odontogenesis of bovine incisors several clearly distinguishable phosphohydrolase activities are observed in the pulp and in dental hard tissues. Using various substrates and inhibitors, unspecific alkaline phosphatase, two isoenzymes of acid phosphatase, Ca2+-activated ATPase and inorganic pyrophosphatase are characterized. The enzymatic activity of alkaline phosphatase in pulp and hard tissues is significantly high at the beginning of dentine and enamel mineralization. The specific activity of this enzyme decreases quite fast with the beginning of root formation, then more slowly, until it reaches a constant final value. Histochemical studies show that during mineralization the maximum of alkaline phosphatase activity is in the subodontoblasts. Lower enzyme concentrations are found in the stratum intermedium and in the outer enamel epithelium during that process.

The specific activities of ATPase, acid phosphatases and pyrophosphatase show little temporal variation during tooth development, but they also appear in a characteristic spatial pattern in the dental tissues.
Monophosphates and Cyclic Phosphates of Some Antiviral Acyclonucleosides: Synthesis, Conformation and Substrate/Inhibitor Properties in Some Enzyme Systems
Authors: Stolarski Ryszard , Ciesla Jaroslaw M. , Shugar David
Published: August 2018

Chemical and enzymatic procedures are described for the synthesis of the monophosphates and cyclic phosphates of the antiviral acyclonucleoside 9-(1,3-dihydroxy-2-propoxym ethyl)-guanine (DHPG), its 3-hydroxymethyl-4-hydroxybutyl analogue, the (/?)-and (S)-epimers of 9-(3,4-dihydroxybutyl)guanine, and 9-(2,3-dihydroxypropyl)guanine.

The structures, and some conformational features, of all the foregoing, were determined by 1H and 31PNMR spectroscopy. Their substrate/inhibitor properties have been examined in several enzyme systems, including ribonucleases, snake venom phosphodiesterase, beef heart and higher plant cyclic nucleotide phosphodiesterases, nuclease P1, and 3′-and 5′-nucleo-tidases. The enzymatic results are considered in relation to the mechanism of the antiviral ac­tivity of the cyclic phosphate of DHPG .
Developmental and Seasonal Variations in the Epicuticular W axes of Beech Leaves (Fagus sylvatica L.)
Authors: Prasad R. B. N. , Giilz Paul-Gerhard
Published: August 2018

The leaf cpicuticular waxes of beech trees (Fagus sylvatica L.) were analyzed continuously all over one vegetation period with preparations every week from April 24 to November 15. The folded leaves in buds contained hydrocarbons, wax esters, benzyl acyl esters, alcohols and fatty acids from the beginning, but not aldehydes. Aldehydes were identified only after 10 days of leaf unfolding. The biosynthesis of wax lipids was rapid in the first three to five weeks till May 30. During this time the wax lipids were doubled quantitatively and the chain length spccifity has also changed in all wax lipid classes. From June to October the composition of the wax lipid classes and also the chain length specifity remained constant with the exception of fatty acids. The biosynthesis of wax lipids was found to be very dynamic in the first five weeks and correlated with the leaf development and growth.
A Further Investigation of Phytoalexin Formation in the Genus Trifolium
Authors: Ingham John L.
Published: August 2018

An earlier study of phytoalexin formation in the genus Trifolium has now been extended to include a further 61 species and subspecies. Using the drop-diffusate method, isoflavonoid phytoalexins were isolated from the fungus-inoculated leaflets of 55 accessions, whilst four others produced the stilbene derivative resveratrol. Phytoalexins could not be obtained from the leaflets of two species, T. billardieri and T. grandiflorum. The pterocarpan medicarpin was the most commonly encountered phytoalexin, occurring alone or in various combinations with the known Trifolium isofjavonoids maackiain (pterocarpan), vestitol, isovestitol, sativan, isosativan and arvensan (all isoflavans). Two additional pterocarpans, 4-methoxymedicarpin from T. cherleri and T. pallescens, and 4-hydroxyhomopterocarpin also from T. pallescens, were recognized for the first time as Trifolium phytoalexins. Re-examination of T. aureum re- vealed that this species produced resveratrol as a phytoalexin and not the isoflavan vestitol as previously described.
The Herbicide Command Does Not Inhibit the Prenyl Diphosphate-Forming Enzymes in Plastids
Authors: Lützow Manfred , Beyer Peter , Kleinig Hans
Published: August 2018

The herbicide Comm and (2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone) does not affect the in vitro activities of the plastid enzymes catalyzing the steps leading from isopen­ tenyl diphosphate to geranylgeranyl diphosphate and phytoene, i.e. the isopentenyl diphos­ phate isomerase, prenyl transferase and phytoene synthase. The extractable activities of these enzymes in herbicide-treated seedlings are also not affected. Nevertheless, the synthesis of chlorophylls and carotenoids in treated seedlings is severely inhibited in vivo. The mode of action of Comm and remains still unknown.
3-Hydroxy-3-methylglutaryl Coenzyme A Reductase from Spruce ( Picea abies). Properties and Regulation
Authors: Boll Meinrad , Kardinal Angelika
Published: August 2018

HM GCoA reductase was identified in seedlings, callus cultures, cell suspension cultures and in needles of spruce ( Picea abies) (L.) (Karst). Activity was found in both the 18 K pellet and in the 105 K pellet with different ratios between the two fractions from the various sources. The enzyme has a pH-optimum of 7.9 and an absolute requirement for NADPH . The presence of a thiol reagent such as dithiothreitol is required for activity. Km for HM G CoA is 20 -25 μM. Detergents have differential effects on the activity.

In seedlings, enzyme activity was considerably higher in the hypocotyls than in the cotyledons. Enzyme activity was high in dark-grown and low in light-grown seedlings. When the light conditions were reversed, levels of activity adapted to the respective new conditions (increase or decline of specific activity).

Aerobic incubations of seedlings, callus cultures or needles in medium containing a carbon source, resulted in a large (up to 20-fold) transient increase of HMGCoA reductase activity. Transfer of stationary phase cell suspension cultures into new medium caused a similarly large increase of activity. A number of carbohydrates induced the enzyme, glucose, fructose and sucrose being most effective. The increase of activity was prevented by cycloheximide. All changes of activity were much more pronounced in the 18 K pellet HMG CoA reductase
Hypothesis for Structure and Oxidation State of Manganese Cluster in Oxygen-Evolving Center Deduced from Their Magnetic Properties
Authors: Nishida Yuzo , Nasu Miyuki
Published: August 2018

Magnetic Interaction, Manganese C om pounds, Photosystem II, Manganese Clusters Based on the investigations for the magnetic interaction in the synthetic binuclear man­ganese com pounds of (μ-oxo bridge and for results by magnetic measurements and EXA FS studies on the native enzyme, it was concluded that there are two dimeric manganese units in the oxygen-evolving center of the photosystem II. One of them is a di-(μ-oxo-bridged dimer with M n -M n distance of 2.7 Å, and it has a Mn2(III/III) oxidation state in both the S1,-and S2-states. A second binuclear unit, which we will call as X-pair, is assumed to have a Mn2(II/III) oxidation state in the S1-state, and is oxidized in the S,-to S2-state transition. The multiline ESR signal observed for the S2-state has been attributed to be due to a partially oxidized (Mn2-(III/IV) oxidation state) of the 2.7 A-pair, which should be formed through the interac­ tion between the 2.7 A-pair with Mn-,(III/III) state and the X-pair of Mn2(III/III) which is gen­ erated in the S1-to S2-state transition.
Direct Measurement of the Flight Behavior of Male Moths to Calling Females and Synthetic Sex Pheromones
Authors: Witzgall Peter , Arn Heinrich
Published: August 2018

The approach of male Lobesia botrana (Lepidoptera: Tortricidae) in the wind tunnel to a source of sex pheromone was studied using two video cameras connected to image processing equipment. Three-dimensional records demonstrate that the flight to calling females is quite direct compared to the zigzag flight reported for other species. Convoluted paths displaying bimodal distribution of track and course angles were only obtained with a synthetic pheromone blend consisting of E-7,Z-9-dodecadienyl acetate, E-7,Z-9-dodecadien-l-ol and Z-9- dodecenyl acetate at the proportions of 1 /0.2/0.05. This suggests that this blend is still suboptimal and that zigzag flight may be due to a lack of precision in upwind motion caused by inadequate composition of the stimulus
Enantioselective Multidimensional Gas Chromatography of Some Secondary Alcohols and Their Acetates from Banana
Authors: Schubert Vera , Diener Renate , Mosandl Armin
Published: August 2018

Using enantioselective MDGC the enantiomeric distribution of alkan-(alken-)2-yl-acetates from bananas is achieved. After simple acetylation their corresponding alcohols 2-pentanol, 2-hexanol, 2-heptanol an d (Z)-4-hepten-2-ol respectively are also exactly stereodifferentiated by the same method.

All compounds investigated -esters as well as alcohols -exhibit a remarkable excess of the (S)-enantiomers.
Local Anesthetic Binding to Thylakoid Membranes. Relation to Inhibition of Light-Induced Membrane Energization and Photophosphorylation
Authors: Günther Gabriele , Laasch Henrik
Published: August 2018

The association of the lipophilic tertiary amine and local anesthetic dibucaine with osmotically shocked chloroplasts of Spinacia oleracea L. cv. Monatol was investigated. Dibucaine, known as an effective inhibitor of thylakoid membrane energization and ATP synthesis, ex­hibited three distinct binding classes with chloroplasts: partitioning in the lipid phase of the membranes, electrostatic screening of negative electrical charges on the thylakoid surface and light-induced association of an as yet unknown nature. Evidence is presented that the mecha­nism of inhibition of the transthylakoid pH gradient, ∆pH, by dibucaine is distinct from ‘classical’ amine-type uncoupling: The inhibitory effect of dibucaine on ∆pH was independent of the initial strength of ∆pH. Light-induced dibucaine binding was independent of the volume of the intrathylakoid space and of the strength of ∆pH as varied by medium pH. Judged from a comparison of the data on dibucaine binding and on inhibition of ∆pH and photophosphorylation, dibucaine bound via partitioning in the membrane lipid phase is responsible for the uncoupler-like effects of the local anesthetic. A mechanism for the inhibition of thylakoid energization by local anesthetic amines is discussed.
Inhibitory Effect of Crown Compound on Photoelectron Transport Activity of Beet Spinach Thylakoid Membranes
Authors: Sabat S. C. , Vijayavergiya V. , Tripathy B. C. , Mohanty Prasanna
Published: August 2018

The effect of K-picrate-18-crown-6 (crown) on the photoelectron transport activity of beet spinach thylakoid membranes was investigated. Addition of micromolar concentration of crown to thylakoid preparation inhibited p-benzoquinone, chloride-indophenol, methyl viologen supported Hill activities maximally by 75 per cent in a concentration dependent manner. However, the photosystem I catalyzed reaction remained insensitive to crown suggesting that crown specifically inhibits photosystem II electron transport. Addition of exogenous electron donors like hydroxylamine or diphenylcarbazide failed to restore the crown induced inhibition of photosystem II electron transport and lowering of steady state chlorophyll a fluorescence yield. These observations suggest that crown also inhibits photosystem II catalyzed electron transport after the donation sites of these exogenous donors. Washing of the crown pre-treated thylakoids with isolation buffer, relieved the crown inhibited electron transport activity, indicating that this inhibition is reversible. Furthermore, in hydroxylamine washed thylakoids which are devoid of O2 evolution capacity, the hydroxylamine induced increase in chlorophyll a fluorescence of variable yield was quenched by the addition of crown. These observations suggest that crown affects the oxygen evolution and inhibits at a site close to photosystem II reaction centres.
Dimethyldithiolanes in the Anal Sac Secretion of the Weasel, Mustela nivalis
Authors: Buglass Alan J. , Darling Frances M. C. , Waterhouse John S.
Published: August 2018

Several dimethyl-1,2-dithiolanes are identified in the anal sac secretion of the weasel. We compare and contrast the results with previously published work.
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.
Iridoids from Plantago carinata Schrad
Authors: Saadi Houcine , Handjieva Nedjalka , Ivanova Antoaneta , Popov Simeon
Published: August 2018

The new iridoid 10-acetylaucubin and the well known iridoids aucubin. melittoside and monomelittoside as well as the rare 6-epiaucubin and 3,4-dihydroaucubin were isolated from aerial parts of Plantago carinata Schrad. This is the first isolation of 6-epiaucubin from Planta-ginaceae plants and of 3,4-dihydroaucubin and monomelittoside from P. carinata Schrad.
Thiazolylidene-Ketonitriles are Efficient Inhibitors of Electron Transport in Reaction Centers from Photosynthetic Bacteria
Authors: Oettmeier Walter , Preuße Silvana , Haefs Michael
Published: August 2018

Thiazolylidene-ketonitriles are efficient inhibitors of photosynthetic electron flow in reaction centers from either Rhodobacter sphaeroides or Rhodobacter capsulatus. Some compounds of this class exhibit a higher inhibitory potency in the bacterial system as compared to photosystem II. Up to now, photosystem II inhibitors were generally less active in photosynthetic bacteria. An azido-thiazolylidene-ketonitrile upon illumination almost exclusively tags the L-subunit in the bacterial reaction center.
Stochastic Treatment of Bump Latency and Temporal Overlapping in Limulus Ventral Photoreceptors
Authors: Lederhofer R. , Schnakenberg J. , Stieve H.
Published: August 2018

We present quantum bumps obtained from flash experiments at the Limulus ventral nerve photoreceptor under voltage clamp conditions. The results are shown and discussed in form of histograms for the latency, amplitude and net charge transfer (current time integral) of the bump current responses. We argue that the experimental latency histogram s cannot be described satisfactorily by chemical models if one assumes that not more than one photon is captured per flash. Instead of, one has to take into account the Poisson statistics of the captures of 0,1,2 ,... photons released by a single flash. We show that the inclusion of Poisson statistics makes the effective latency histograms of flash responses typically asymmetric and skewed to wards short latencies as compared to that of model histograms for one-photon responses. Our conjecture also implies that under our experimental conditions a fraction of up to 20% of the bump responses evoked by a flash should be suspected to be superpositions of two ore more one-photon responses which cannot be separated by any kind of evaluation analysis. Consequently, the average values of amplitudes and net charge transfers of the light-evoked bump responses are expected to be overestimated as compared to that of true one-photon responses. This hypothesis is confirm ed by a numerical simulation of light-evoked bump responses using experimentally recorded spontaneous bumps (at times larger than 1 s after the flash) as the simulation material. We show that the superposition of one-photon events in the light-evoked bump responses due to Poisson statistics settles the question why their amplitudes and net charge transfers are found to be larger than that of the spontaneous bumps. We suggest that true one-photon responses evoked by a light flash and spontaneous bumps start from the same activated rhodopsin state and take the same biochemical pathway.
Naturally Occurring Coumaranochroman-4-Ones: A New Class Of Isoflavonoids From Lupins And Jamaican Dogwood
Authors: Tahara Satoshi , Moriyam Masaaki , Orihara Sunao , Ingham John L. , Kawabata Jun , Mizutani Junya
Published: August 2018

A further investigation of the isoflavonoid components of Piscidia erythrina, Lupinus alhus and L. luteus has revealed the presence of 3-hydroxy- and 3-methoxy-coumaranochroman- 4-ones. These compounds are the first known representatives of a new type of naturally occurring isoflavonoid. Using a combination of chemical and spectroscopic methods, the com pounds were identified as 3,5,7,4′-tetrahydroxy-5′-methoxy-3′-(3,3-dimethylallyl)coumaranochroman- 4-one (piscerythrol, 1), 3,5,7,4′-tetrahydroxy-6,3′-di(3,3-dimethylallyl)coumaranochroman- 4-one (lupinol A, 3), 5,7,4′-trihydroxy-3-methoxy-6,3′-di(3,3-dimethylallyl)- coumaranochroman-4-one (lupinol B, 6) and 3,5,7,4′-tetrahydroxy-6-(3,3-dimethylallyl)- coumaranochroman-4-one (lupinol C, 7). All four isoflavonoids were found to have the cis relative configuration at C-2/C-3. Possible biogenetic relationships between the coumaranochroman- 4-ones and other isoflavonoids (isoflavones and coumaronochrom ones) found in Piscidia and Lupinus are briefly discussed
Further Studies Of Sequestration Of Alkaloids In Papaver Somniferum L. Latex Vacuoles
Authors: Roberts Margaret F. , Homeyer B. C. , Pham Thi D. T.
Published: August 2018

The uptake and sequestration of alkaloids by latex vacuoles of P. somniferum sedimenting at 900 x g and 1100 x g were studied; both populations take up morphine effectively. Morphine uptake by the 1100 x g vacuoles was stimulated by exogenous ATP and, after uptake of large amounts of alkaloid, both populations were stimulated by exogenous ATP to take up further morphine; this effect was no longer present in 900 x g vacuoles isolated from the latex of more mature capsules. Uptake by 1100 x g vacuoles was more sensitive to temperature than that of 900 x g vacuoles. Determination of the proton gradient across the vacuolar membrane (△pH), controlled dissipation of △pH through the use of NH4Cl, and correlation with morphine uptake demonstrated that morphine uptake was strongly dependant on the maintenance of △pH. Inhibitors designed to produce loss of protons from the vacuole had, however, little effect on the system. Nitrate, as an inhibitor of tonoplast ATPase, had an inhibitory effect on morphine uptake by the 1100 x g vacuoles. Uptake of meconate, [35S]sulphate and L-[U14C]malate, important acid constituents of the 900 x g vacuoles was investigated. Uptake of sulphate and malate was continuous and saturation was not reached; the rate of uptake of sulphate and malate was much lower than that of morphine and other alkaloids, and uptake of meconate by these vacuoles was not detected. Studies on specificity of alkaloid uptake with the 900 x g vacuoles indicated no absolute preference for either the ( + )- or the (-)-isomer of codeine. Noscapine uptake was stimulated by ATP under conditions where ATP had no effect on morphine uptake. Nicotine was not taken up, but low levels of caffeine and l-m ethoxycanthin-6-one were taken up, but less effectively than morphine or noscapine. Uptake of alkaloids by P. somniferum latex vacuoles is dependant on the maintenance of tonoplast △pH and an ATPase generates this △pH. Sequestration appears to involve protonation and anion-cation stabilization involving meconate and sulphate. The specificity of alkaloid uptake suggested no clear correlation with pK or lipophilicity, and some sort of channel mechanism, more related to alkaloid shape is suggested
Calorimetric Study On The Interactions Of 5-n-Heptadec(en)Yiresolcinols From Cereal Grains With Zwitterionic Phospholipid (DPPC)
Authors: Hendrich Andrzej B. , Kozubek Arkadiusz
Published: August 2018

The effect of two 5-n-alk(en)ylresorcinol* (17:1 and 17:0) homologs at the concentrations of 5 - 20% on the thermotropic properties of dipalmitoylphosphatidylcholine in hydrated bilayers has been studied. The effect is different, depending on unsaturation of the aliphatic chain of resorcinol derivative. Saturated homologue ( 5 - 2 0 m ol% ) induces disappearance of the pretransition , increase of the main transition temperature and a half-width of the sition peak. Unsaturated homologue shifts pretransition towards higher temperatures, and similarly to the saturated one increases transition half-width but decreases the transition temperature, decreases the transition heat content and induces some phase separation
Slit Scan Flow Cytometry Of Isolated Chromosomes Following Fluorescence Hybridization: An Approach Of Online Screening For Specific Chromosomes And Chromosome Translocations
Authors: Hausmann Michael , Dudin Gertrud , Aten Jacob A. , Heilig Rainer , Diaz  , Cremer
Published: August 2018

The recently developed methods of non radioactive in situ hybridization of chromosomes offer new aspects for chromosome analysis. Fluorescent labelling of hybridized chromosomes or chromosomal subregions allows to facilitate considerably the detection of specific chromosomal abnormalities. Formany biomedical applications (e.g. biological dosimetry in the low dose range), a fast scoring for aberrations (e.g. dicentrics or translocations) in required. Here, we present an approach depending on fluorescence in situ hybridization of isolated suspension chromosomes that indicates the feasibility of a rapid screening for specific chromosomes or translocations by slit scan flow cytometry. Chromosomes of a Chinese hamster x human hybrid cell line were hybridized in suspension with biotinylated human genomic DNA . This DNA was decorated with FITC by a double antibody system against biotin. For flow cytometry the chromosomes were stabilized with ethanol and counterstained with DAPI or propidium iodide (PI). An experimental data set of several hundred double profiles was obtained by two parameter slit scan flow cytometry and evaluated automatically. The evaluation algorithm developed allowed a classification of chromosomes according to the number of centromeres and their chromosomal positions in less than 1 msec per individual profile. Approximately 20% of the measured DAPI profiles showed a bimodal distribution with a significant centromeric dip indicating a “ normal” chromosomal morphology and a correct alignment in the flow system. In many cases, profiles of a “normal” bimodal fluorescence distribution of the DNA stain (DAPI, PI) were correlated with a “ normal” FITC profile. Due to their centromeric indices these profiles agreed well to the expected human chromosomes of the cell line. In some cases of “ normal” DAPI (PI) profiles, “aberrant” FITC profiles were observed. These were interpreted as interspecies translocation chromosomes. For all results, there was a good agreement between flow cytometry and microscopic observations (digital image analysis)
Electrogenic Na+- Ca2+ Exchange Contributes To The Light Response Of Fly Photoreceptors
Authors: Hochstrate Peter
Published: August 2018

The response of fly photoreceptors to light stimuli of high intensity consists of a fast transient depolarization caused by the activation of light-dependent channels and a delayed after depolarization. The after depolarization was reversibly reduced or abolished when the extracellular Na+ had been replaced by Li+, tris or choline. Na+ specificity, the dependence on the concentrations of Na+ and Ca2+ as well as the polarity of the effect suggest that electrogenic Na+- Ca2+ exchange contributes to the after depolarization. Prolonged incubation in Na+-free media also led to the reversible suppression of the fast response component, which is most probably due to an increase in the intracellular Ca2+ concentration caused by the inhibition of Na+ -Ca2+ exchange. Evidence is presented that the Na+- Ca2+ exchange system in fly photo receptors also transports Sr2+
New Triterpenes from the Frond Exudate of the Fern Notholaena rigida
Authors: Arriaga-Giner F. J. , Rullkötter J. , Peakman T. M. , Wollenweber E.
Published: August 2018

Two new triterpenoids, isolated from the frond exudate of the fern Notholaena rigida, have been identified as 3 β, 12 β,25-trihydroxy-(20 R-24 R)-epoxy-dammarane- 12-acetate (1), and 24 R,25-diO-isopropyliden-9(19)-cyclolanostan-3 β-ol (5), based on NMR spectroscopic studies.
New Isoflavone Glucosides from White Lupin (Lupinus albus L.)
Authors: Shibuya Yusuke , Tahara Satoshi , Kimura Yutaka , Mizutani Junya
Published: August 2018

Further investigation of polar constituents in white lupin roots revealed the presence of genistein 7-O-β-glucoside (1 a), genistein 4′-O-β-glucoside (1 b), 2′-hydroxygenistein 7-O-β-glucoside (2 a) and 2′-hydroxygenistein 4′-O-β-glucoside (2 b) as simple isoflavone gluco­ sides; luteone 7-O-β-glucoside (3 a), licoisoflavone A 7-O-β-glucoside (4 a) and licoisoflavone A 4′-O-β-glucoside (4 b) as prenylated (= 3,3-dimethylallyl-substituted) isoflavone glucosides; and genistein 7-O-β-(6′-O-malonyl)glucoside (1 am) and 2′-hydroxygenistein 7-O-β-(6″-O-malonyl)glueoside (2 am) as malonylated isoflavone glucosides. Six compounds (2 a, 2 b, 3 a, 4 a, 4 b, and 2 am) are new naturally occurring isoflavone glucosides.
Identification of Tropane Alkaloids in Hairy Root Cultures of Hyoscyamus albus
Authors: Doerk Katja , Witte Ludger , Alfermann A. Wilhelm
Published: August 2018

Tropane alkaloids are typical natural products of solanaceous plants. The patterns of these alkaloids from hairy roots of Hyoscyamus albus were determined by GC-MS analysis. 18 alka-loidal compounds were detected, six of them only in trace amounts. Some of these alkaloids, namely hygrine, 3a-acetoxytropane, 3 β-acetoxytropane and 6-hydroxylittorine as well as the trace compounds N-methylpyrrolidinylhygrine, phenylacetoxytropane and two isomers of feruloyloxytropane were not previously reported to be components of this species. The major compounds formed were found to be hyoscyamine and littorine.
Control by Light Quality of Chlorophyll Synthesis in the Brown Alga Desmarestia aculeata
Authors: López-Figueroa F.
Published: August 2018

The chlorophyll synthesis in the brown algae Desmarestia aculeata is affected by light quality and by the nutrient state in the medium before the illumination. Pulses of 5 min of red, green and blue light together with 200 μM nitrate in plants growing under natural conditions deter­ mined similar induction of chlorophyll synthesis. However, when the plants were incubated previously under starvation conditions the light effect was different. The induction of chlorophyll synthesis was greater after blue and green light than after red light pulses. Red-light photoreceptor was only involved in the chlorophyll synthesis under no nutrient limitations and under starvation conditions after previous illumination with blue light followed by far-red light. The induction of chlorophyll synthesis by green and blue light pulses applied together with nitrate was greater when the algae were incubated in starvation conditions than in natural conditions (normal nutrient state).

Because all light effects were partially reversed by far-red light the involvement of a phyto-chrome-like photoreceptor is proposed. In addition, a coaction between blue-and a green-light photoreceptors and phytochrome is suggested.
Photoautotrophic Cultured Plant Cells: A Novel System to Survey New Photosynthetic Electron Transport Inhibitors
Authors: Sato Fumihiko , Yamada Yasuyuki , Kwak Sang Soo , Ichinose Katsunori , Kishida Mitsuhiro , Takahashi Nobutaka , Yoshida Shigeo
Published: August 2018

The responses of photoautotrophic (PA) cultured cells of tobacco (Nicotiana tabacum cv. Samsun NN) and liverwort (Marchantia polymorpha L.) to thirty-eight cyclohexanedione derivatives were surveyed. Each derivative was also tested for inhibitory activity on photosynthetic electron transport (PET), using isolated thylakoids, and herbicidal activity, using seed­ lings and mature plants. Comparison of the results from the different assays showed that the responses of PA cells to each com pound correlated more closely with the responses of seed­ lings and mature plants than did the results of the Hill reaction assays. Our findings suggest that PA cultured cells would be a suitable screening material for identifying potential herbicides with PET-inhibiting activity.
Long-Term Effect of Diuron on Chlorophyllous Callus of Bromus erectus: Lipid Composition
Authors: El Kaoua Mimoun , Duval Evelyne , Laval-Martin Danielle
Published: August 2018

The selection of plants resistant to photosynthetic herbicides is limited by the low rate of success in obtaining a photosynthetic callus. An attempt was made to induce diuron tolerance with chlorophyllous tissue strains of Bromus erectus: growth, chlorophyll contents and total fatty acids were studied during four months of photoheterotrophic growth in the presence or absence of 6 μM diuron. The presence of the herbicide, which reduced the fresh weight by 40%, provoked increases in chlorophyll levels by 2-or 3-fold, and in galactolipids (especially DGDG) which were enriched in linolenic acid content. These results, closely related to already described characteristics of herbicide-resistant material, suggest that callus of Bromus erectus could constitute an interesting photosynthetic in vitro material.
Effect of Azide on the ATPase Activity of Isolated CF1
Authors: Minkov Ignat B. , Strotmann Heinrich
Published: August 2018

The effect of azide on M g2+-and Ca2+-dependent ATPase of differently activated CF1 isolated from spinach chloroplasts was studied. It is shown that Mg2+-ATPase activity is sensitive towards azide irrespective of the applied method of enzyme activation. Heat-or trypsin-acti-vated Ca2+-ATPase is also inhibited, whereas methanol-and octylglucoside-stimulated or DTT-activated Ca2+-ATPase is not affected by azide. Preincubation of the DTT-activated enzyme with low concentrations of Mg2+ induces azide susceptibility of the Ca2+-dependent ATPase.
Phenotypic Traits and Regulatory Role of RNA Folding in Molecular Selection
Authors: Fernández Ariel
Published: August 2018

We concentrate on instances in which the phenotypic expression of information encoded in an RNA primary sequence might be revealed by the folding of the RNA itself. We have discov­ered that this situation finds concrete realization in the design of RNA molecules capable of maximizing the rate of autocatalytic synthesis when incubated with viral Qβ-replicase. This requires that we introduce the notion of phenotypic traits at the molecular level. Thus, the problem of finding RNA sequences whose phenotype favorably influences propagation amounts to finding RNA sequences which fold so as to optimize enzymatic performance and are in addition endowed with the proper recognition sites. The proof that these two problems are indeed equivalent has two steps: First we predict the metastable folded structures formed as a template RNA chain grows by sequential incorporation of nucleotides. The transient folded states appear to be involved in the regulation of the enzyme activity and they occur in a manner which is “oblivious” of thermodynamic time scales. Secondly, we compute the time-dependent activation energy for relaxation of each intermediate structure. This is done to establish constraints necessary for optimization of the regulatory role of RNA folding. The search for prospective template sequences is subject to such constraints. Our results aim at elucidating an optimization process realized by molecular selection in de novo (template-free) RNA synthesis by Qβ-replicase. We argue that the phenotype which mediates selection is given by metastable folding which emerges together with the printing of the genotype, that is, within the time span of a replication turnover.
Specific Crystal Chemical Interactions between Carcinogenic Aromatic Compounds and Cholesterol
Authors: Contag Bodo
Published: August 2018

Polycyclic aromatic hydrocarbons and aromatic amines exercise a highly specific influence on the crystallization of cholesterol. The strength of these non-covalent, presumably epitaxial interactions correlates with the carcinogenic activity of these substances. The presented results are in support of the assumption that a specific process of adsorption and crystallization with cholesterol of the plasma membrane takes place during the initial phase of the carcinogenesis by aromatic compounds.
Studies in Enteric Anthelmintics: Activity Profile of Prodrug of a Bisbenzimidazole
Authors: Khan A. M. , Gupta Suman , Katiyar J. C. , Singh Sudhir K. , Sharma V. L. , Sharma Satyavan , Bhaduri A. P.
Published: August 2018

The comparative anthelmintic activity of a possible prodrug, 2,2′-dicarbomethoxyamino-5,5′-dibenzimidazolyl methanol (2) with its parent compound 2,2′-dicarbomethoxyamino-5,5′-dibenzimidazolyl ketone (1) and the reference drug mebendazole (3 a) is reported. At a dose of 25 mg/kg, compound 2 was 100% effective against Ancylostoma ceylanicum in hamsters. Compound 2 also exhibited a similar order of activity against Syphacia obvelata, Hymenolepis nana and H. diminuta at a dose of 100 mg/kg. The drug exhibited lethal effects against metamorphic forms of A. ceylanicum at a dose of 100 mg/kg. However the trichostrongylids, Nippostrongylus brasiliensis remained unaffected up to a dose of 250 mg/kg of 2. Both 1 and 3 a exhibited inferior activity than 2 except against adult A. ceylanicum. The activity of 1 and 2 has been explained on the basis of their ability to resist systemic hydrolysis resulting in higher concentration of the active drug in biophase.
Directed Cell Movement with Steric Exclusion
Authors: Gruler H.
Published: August 2018

The space-dependent density of cells is evaluated for the following situation: (i) The cells are forced to make a directed movement (ii) the space for the cellular migration is restricted. The steady state distribution density is obtained when the drift current density equals the diffusion current density. The analogy to the Boltzmann statistics is shown. In a further step the cellular volume is introduced. For this case the density distribution is described in analogy to the Fermi statistics. The necrotactic response of granulocytes is used to verify the model.
No Correlation between Plasmid Content and Ability to Reduce Nitrate in Wild-Type Strains of Rhodobacter capsulatus
Authors: Witt Astrid , Klemme Jobst-Heinrich
Published: August 2018

Patterns of endogenous plasmids and nitrate reductase activities were analyzed in the phototrophic bacterium Rhodobacter (Rb.) capsulatus. From 10 strains investigated (including a UV-induced plasmidless nit- mutant), 4 were unable to grow photosynthetically with nitrate as N-source and lacked nitrate reductase activity (nit strains). Irrespective of the nit phenotype, all wildtype strains contained at least one large plasmid with a size ranging from 93 to 134 kb. Thus, other than in plasmid- cured mutants (J. C. Willison, FEMS Microbiol. Lett. 66, 23-28[1990]), in wild-type strains of Rb. capsulatus the nit- character was not related to lack of endogenous plasmids.
Growth Inhibitions on Human Cancer Cell Cultures with the Indole Sulphur-Containing Phytoalexins and Their Analogues
Authors: Tempête Christiane , Devys Michel , Barbier Michel
Published: August 2018

Cell growth inhibitions on human cancer cell cultures were determined for the indole sulphur-containing phytoalexins cyclobrassinin, brassilexin (previously isolated from vegetables of the Cruciferae family) and their synthetic analogues 5-methoxybrassilexin and homocyclobrassinin. The most biologically active of these products is brassilexin (LD50= 8 μg/ml).
Isoflavone Glycoside Formation in Transformed and Non-Transformed Suspension and Hairy Root Cultures of Lupinus polyphyllus and Lupinus hartwegii
Authors: Berlin J. , Fecker L. , Rügenhagen C. , Sator C. , Strack D. , Witte L. , Wray V.
Published: August 2018

Transformed cell suspension and hairy root cultures were established by infecting seedlings of Lupinus polyphyllus and L. hartwegii with various wild type strains of Agrobacterium tume-faciens and A. rhizogenes. Transformation of the cultures was confirmed either by their phyto­hormone autotrophy, detection of opines or southern analysis. Glueosides of genistein and 2′-hydroxygenistein, were found to be the main secondary metabolites in normal and trans­formed suspension cultures as well as in hairy root cultures. Although some of the isoflavone glycosides of the cultures were apparently new constituents of Lupinus, they were afterwards also found in young seedlings.
Schweres Wasser (D2O) als Protektivum proteinhaltiger Arzneimittel. Beispiel: humane Cholinesterase/Protein Drugs Stabilized by Heavy Water (D2O). For Example: Human Cholinesterase
Authors: Heyde Ch. , Wenzel M.
Published: August 2018

Looking for a possible protective effect of heavy water on proteins, cholinesterase and lac­tate dehydrogenase in combination with D2O and further protective substances were exposed to a temperature of 60 °C (for 10 min) and about 45 °C (for several days). In combination with glycerine there resulted an additive protective effect; with NaCl and/or albumin being added the individual effects raised to a higher level. In the cold D2O protects cholinesterase only against acid denaturation, but in combination with warmth also against basic denaturation.
Bioactive Chemical Bond Systems in Safeners and Prosafeners
Authors: Dutka Ferenc
Published: August 2018

Acetals and ketals involving a dichloromethyl group on their central carbon atom were found to be active or highly active as safeners of corn against thiocarbamate and chloroacet-anilide herbicide injury. A mechanism for the biotransformation of these compounds as pro­safeners to the actual dichloroacetic ester safeners is proposed.

Similarly, S-and N-analogues of the cyclic acetals (ketals) which show safener activity can also be considered as prosafeners because they can be converted in the biophase by the same mechanism into actual safeners such as dichloroacetic thiolesters or dichloroacetamides sup­porting the bioactivation hypothesis.

Characteristic bioactive chemical bond systems in safeners and prosafeners are suggested.
Chemical Reactivity and Safener Activity of Acetal Compounds
Authors: Ekler Zsigmond , Dutka Ferenc
Published: August 2018

Although detailed examinations have been published on structure-activity relationships of herbicide safeners, only a few data are available on chemical reactivity-safener activity relationships. Chemical reactivity of acetamide type compounds as well as their safener activity against thiocarbamate herbicides change with the number of chlorine substituents in the order: non-chlorinated < monochloro < dichloro. Several compounds of another chemical group, acetals (e.g. MG-191, 2-dichloromethyl-2-methyl-1,3-dioxolane), are also effective safeners for thiocarbamate herbicides. According to our growth room studies, the safener activity of acetals also increases with increasing chlorine content up to two chlorine atoms on the same carbon. A number of differently chlorinated acetals have been synthesized and their acid-catalyzed hydrolysis rate determined in order to establish a relationship between their bioactivity and chemical reactivity. The hydrolysis rate order of acetals containing no, one or two chlorine atoms: non-chlorinated > monochloro > dichloro, is just the opposite than what has been found for acetamides. Thus, safener activity of acetals increases with decreasing chemical reactivity. The opposite reactivity order of acetamides and acetals can be explained by the different mechanisms of their hydrolysis. Dichloroacetals may not be effective safeners in their original structure. In plants, however, they can be biologically activated to active safeners by a transformation other than hydrolysis.
An Overview of the Mechanisms of Action of Herbicide Safeners
Authors: Hatzios Kriton K.
Published: August 2018

Herbicide safeners are chemicals used for manipulating the tolerance of large-seeded grass crops to selected soil-applied herbicides. The physiological interactions of herbicides and their respective safeners are characterized by the following facts: a) safeners are most effective when applied prior to or simultaneously with the herbicides whose injury they prevent; b) safeners exhibit a high degree of botanical and chemical specificity protecting only certain grasses against injury caused from specific classes of herbicides; and c) protected grass crops are moderately tolerant to the antagonized herbicides. At the biochemical level, safeners may act either as “bioregulators” regulating the amount of a given herbicide that reaches its target site in an active form or as “antagonists” of herbicidal effects at a similar site of action. A safener-induced enhancement of herbicide detoxication in protected plants is currently viewed as the most apparent mechanism for the action of the currently available safeners. Safeners enhance the conjugation of carbamothioate and chloroacetanilide herbicides with glutathione either by elevating the levels of reduced glutathione (GSH) or by inducing the activity of specific glutathione S̱-transferases (GSTs). A safener-induced enhancement of the activity of other degradative enzymes such as the cytochrome P450-dependent mixed function oxidases or UDP-glucosyl transferases seems to be important for the protective action of safeners against injury from aryloxyphenoxypropionate, imidazolinone, and sulfonylurea herbicides. Metabolic processes related to acetyl-CoA metabolism have been implicated as likely target sites for a competitive antagonism between safeners and chloroacetanilide or carbamothioate herbicides. At the molecular level, the “gene activation” and “gene amplification” theories offer a likely explanation for the action of safeners.
Comparative Effectiveness and Mode of Action of Safeners for Chloroacetamide Herbicides in Maize Seedlings
Authors: Ekler Zsigmond , Stephenson Gerald R.
Published: August 2018

In growth room bioassays, four herbicide safeners {BAS-145138: 1-dichloroacetyl-hexa-hydro-3,3,8a-trimethyl-pyrrolo(1,2a)pyrimidin-6(2H)-one, dichlormid: N,N-diallyl-2,2-dichloroacetamide, flurazole: phenylmethyl 2-chloro-4-(trifluoromethyl)-5-thiazole-carboxylate and MG-191: 2-dichloromethyl-2-methyl-1,3-dioxolane} were compared for their effective­ ness in reducing metazachlor {N-(2,6-dimethylphenyl)-N-(1-pyrazolylmethyl)-chloroacet-amide} injury to maize seedlings. Three of these compounds (BAS-145138, dichlormid and MG-191) and two different compounds (AD-67: N-dichloroacetyl-1-oxa-4-azaspiro-4,5-de-cane and DKA-24: N ,N2-diallyl-N2-dichloroacetylglycineamide) were also evaluated as safe­ners for acetochlor {N-(2-ethyl-6-methylphenyl)-N-(ethoxymethyl)chloroacetamide} in maize seedlings. Both BAS-145138 and dichlormid were highly effective as safeners for metazachlor and BAS-145138 and DKA-24 were equally good safeners for acetochlor.

Metazachlor and acetochlor uptake and metabolism by maize seedlings were enhanced sig­nificantly in response to treatment with every safener examined. Rates of metazachlor and acetochlor uptake and metabolism were greatest in seedlings treated with BAS-145138 -the most effective safener.

In the absence of any safener treatment, the non-enzymatic conjugation of the herbicides with glutathione either exceeded (metazachlor) or was similar (acetochlor) to enzymatic conjugation. However, the rate of enzymatic conjugation was generally increased by safener treat­ ment. This was particularly true when the herbicide (14C-labeled) was employed as a conjuga­tion substrate instead of the less specific substrate, CDNB (1-chloro-2,4-dinitrobenzene).

A significant linear correlation was observed between safener effectiveness and rates of metazachlor metabolism or glutathione S-transferase activity in maize seedlings. However, a similar correlation could not be established for the five compounds evaluated as safeners for acetochlor.