bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of UV-B Radiation on the Lipid and Fatty Acid Composition of Synchronized Ditylum brightwellii (West) Grunow
Authors: Döhler Günter , Biermann Thomas
Published: August 2018

The marine diatom Ditylum brightwellii (West) Grunow isolated from the Baltic Sea could be synchronized by a light/dark rhythm of 6.5:17.5 h (white light intensity 8 W m-2) at 18 °C and 0.035 vol.% CO2. Content of protein, DNA and RNA increased linearly up to the end of the cell cycle. Pigments (chlorophyll a, chlorophyll c1 + c2, carotenoids) and galactolipids were synthesized in the light period only. A lag phase of 2 h was observed in the biosynthesis of sulphoquinovosyl diacylglycerol and phosphatidylglycerol. Formation of phosphatidylglycerol and phosphatidylcholin continued in the dark period (30% and 28%, respectively). The pattern of major fatty acids (C14:0, C16:1, C16:0, C18:1 and C20:5) varied during the cell cycle of Ditylum.

Biosynthesis of acyl lipids was reduced in dependence on the UV-B dose. The most sensitive lipid was digalactosyl diacylglycerol (total inhibition at 585 J m-2), whereas phosphatidylcholin was less affected (20% reduction). UV-B radiation during the dark period had no effect on the lipid and pigment content. Strongest inhibitory effect of UV-B on cell division, synthesis of protein, pigments, sulphoquinovosyl diacylglycerol and phosphatidylglycerol was found after UV-B radiation at the beginning of the cell cycle (0.-2. h). An exposure time at the end of the light period (4.-6. h) led to a marked damage on the synthesis of monogalactosyl diacylglycerol and phosphatidylglycerol. These findings indicate a stage-dependent response of Ditylum to UV-B irradiance. The impact of UV-B resulted in an increase of unsaturated long chained fatty acids (C18, C20) and in a diminution of short chained fatty acids (C14, C16). Content of ATP was not affected by UV-B radiation under the used conditions. The inhibitory effect of UV-B on synthesis of DNA, RNA, protein and acyl lipids was mainly reversible. Results were discussed with reference to UV-B damage on the enzymes involved in the biosynthesis of acyl lipids and by a reduction of available metabolites.
Lipoxygenase Forms Located at the Plant Plasma Membrane
Authors: Nellen Arndt , Rojahn Barbara , Kindl Helmut
Published: August 2018

In cucumber cotyledons (Cucumis sativus L.) containing several soluble and particulate forms of lipoxygenase (LOX), the location of LOX forms in microsomes has been studied. We concentrated on the question whether the plasma membrane contains one or more forms of LOX. As methodology, we applied both the two-phase partition with polyethylene glycol/dextran and density gradient flotation of plasma membrane-enriched membrane fractions. Both methods show that a high percentage of the microsomal LOX can be attributed to the plasma membrane. Emphasis was put on the findings that the LOX located at the plasma membrane consisted of a species behaving as an integral membrane protein and another form characterized as a peripheral membrane protein by solubilization with carbonate. With long distance SDS-PAGE and immunodecoration using anti-lipid body LOX antiserum, it is possible to distinguish between microsomal LOX forms by small but significant differences in size. Treatment of seedlings with methyl jasmonate led to an enhanced level of LOX at the plasma membrane.
Polyols that Accumulate in Renal Tissue Uncouple the Plasma Membrane Calcium Pump and Counteract the Inhibition by Urea and Guanidine Hydrochloride
Authors: Sola-Penna Mauro , Lemos Adriana dos Passos , Fávero-Retto Maely P. , Meyer-Fernandes José Roberto , Vieyra Adalberto
Published: August 2018

Sorbitol and mannitol, two stereoisomeric osmolytes, inhibit the ATP-dependent Ca2+ transport in inside-out vesicles derived from basolateral membranes from kidney proximal tubules. This inhibition (I0,5 = 400 and 390 mᴍ respectively) cannot be attributed to an in­ crease in Ca2+ permeability, since the rate of EGTA-stimulated Ca2+ efflux from preloaded vesicles is not modified by these osmolytes. In the presence of 1 ᴍ sorbitol or mannitol, Ca2+ uptake is inhibited by 70 and 75%, respectively. Since the Ca2+-stimulated ATPase activity is unaffected, sorbitol and mannitol uncouple the Ca2+ transport from the ATPase activity. The inhibition of Ca2+ transport by these osmolytes is reversible, since the inhibition dis­appears when the vesicles are preincubated with 1 ᴍ sorbitol or mannitol and then diluted 25-fold in reaction medium to measure Ca2+ accumulation. On the other hand, these osmo­lytes protect the (Ca2+ +Mg2+)ATPase from the inhibition of Ca2+ transport and ATPase activity by urea and guanidinium. These data suggest that the high concentrations of polyols that renal cells accumulate during antidiuresis, may regulate Ca2+ transport across the plasma membrane. In addition, polyols may protect the (Ca2+ + Mg2+) ATPase from the deleterious structural effects of urea, a compound that also accumulates during antidiuresis.
Sulphite as Intermediate Sulphur Compound in Anaerobic Sulphide Oxidation to Thiosulphate by Marine Cyanobacteria
Authors: Rabenstein Andreas , Rethmeier Jörg , Fischer Ulrich
Published: August 2018

Anaerobic sulphide oxidation in the light was studied with seven cyanobacterial strains isolated from the southern Baltic Sea. All strains oxidized sulphide (1.2-3.5 mM) stoichio-metrically to thiosulphate. No elemental sulphur could be detected as end product of anoxy-genic photosynthesis. Sulphite as intermediate sulphur compound was released into the growth medium during anaerobic sulphide oxidation by these cyanobacteria. The formation of sulphite from sulphide was inhibited by the photosynthesis inhibitor DCMU.

The cyanobacterium Oscillatoria sp. strain BO 32 produced another so far not identified intermediate sulphur compound which was probably stored within the cells.
Consequences of High CO2-Concentrations in Air on Growth and Gas-Exchange Rates in Tobacco Mutants
Authors: He P , Bader K. P , Radunz A , Schmid G.H
Published: August 2018

Wild type tobacco N. tabacum var. John William’s Broadleaf and the tobacco aurea mutant Su/su were permanently grown under 700 ppm CO2 in air. In comparison to plants grown under 350 ppm CO2 in air but under otherwise identical conditions growth was substantially enhanced. Gas exchange measurements carried out by mass spectrometry show that the rate of photosynthesis in the wild type and in the mutant is increased by more than 100%. The photorespiratory rate in the wild type measured as 18O2-uptake in the light in the “700 ppm CO2-plants” is not reduced to the extent expected or deduced from experiments in which the 350 ppm system responds under in vitro conditions to 700 ppm CO2. An analysis of the induction kinetics of room temperature fluorescence kinetics of the adapted (700 ppm CO2) system and the control system (350 ppm CO2) under various CO2-partial pressures shows that permanent growth under the elevated CO2-partial pressure leads to a structural modification of the photosynthetic apparatus.
Quantification of Ecdysteroids by Immunoassay: Comparison of Enzyme Immunoassay and Radioimmunoassay
Authors: Pascual Nuria , Bellés Xavier , Delbecque Jean-Paul , Hua Yue-Jin , Koolmanc Jan
Published: August 2018

The performance of enzyme immunoassay (EIA) and radioimmunoassay (RIA) in the quantitative analysis of ecdysteroids was compared. The EIA was found to be at least equivalent to the RIA with respect to analytical range and sensitivity and to be more comfortable with respect to safety and time saving. When biological samples were analyzed by both assays a good correlation (r = 0.83) was found. Since the EIA has certain advantages over the RIA, we now recommend the use of the former assay for the quantification of ecdysteroids.
Comparison on Reactivity of Fe(III) and AI(III) Compounds in the Presence of Hydrogen Peroxide: Its Relevance to Possible Origin for Central Nervous System Toxicity by Aluminum Ion
Authors: Nishida Yuzo , Ito Sayo
Published: August 2018

The iron(III) compounds with several aminocarboxylate chelates containing an aryl or furan substituent exhibit high activity in enhancement of the reactivity of hydrogen peroxide, leading to facile hydroxylation at benzene ring, and to degradation of furan ring, but no such activity was observed for the corresponding Al(III) compounds. These results were inter­preted in terms of the molecular orbital consideration, and lack of the activity of the Al(III) complexes was attributed to lack of electrophilic nature of the peroxide adduct due to the absence of a d-orbital: this may explain the fact that there were no tumors in Al-NTA (nitrilotriacetic acid)-treated rats. Based on the facts observed in this study, the decreased function of iron(III) ions for synthesizing neurotransmitters in the brain was assumed to be one of the possible origin for the neurotoxicity by injection of the Al(III) salts in vivo.
Caffeine Metabolism in High and Low Caffeine Containing Cultivars of Camellia sinensis
Authors: Ashihara Hiroshi , Shimizu Hisayo , Takeda Yoshiyuki , Suzuki Takeo , Gillies Fiona M. , Crozier Alan
Published: August 2018

The metabolism of [8-14C ]adenine and [2-14C]caffeine was examined in leaf segments from flush shoots of tea cultivars with high and low caffeine content. The caffeine biosynthesis pathway from AMP via theobromine was operative in both high and low caffeine containing cultivars. There was a m ore rapid rate of caffeine biosynthesis from [8-14C ]adenine in the high caffeine cultivars while the rate of degradation of both adenine nucleotides and caffeine into CO2 was greatest in cultivars with a low endogenous caffeine content. Cell-free p reparations from tea shoots contained an N-methyltransferase, that is a keyenzyme in the caffeine biosynthesis pathway; more in-vitro activity was detected in preparations from high caffeine containing cultivars. The data obtained suggest that the high caffeine containing cultivars have a more rapid rate of caffeine biosynthesis and a slower rate of caffeine catabolism than cultivars with a low endogenous caffeine content
Homocysteine-Induced Oxidative Damage: Mechanisms and Possible Roles in Neurodegenerative and Atherogenic Processes
Authors: Schlüssel Elke , Preibisch Gudrun , Piitter S. , Elstner E. F.
Published: August 2018

Increased blood plasma concentrations of the sulphur amino acid homocysteine (“homocysteinemia”) have been brought into context with neurodegenerative and arteriosclerotic symptoms and diseases.

We recently reported on biochemical model reactions on the prooxidative activity of hom ocysteine including the desactivation of Na+/K+-ATPases and hemolysis of erythrocytes (Preibisch et al., 1993). In this communication we extend our model reactions including the oxidation of methionine, metabolization of pyridoxalphosphate and dihydroxyphenylalanine, desactivations of transaminases and peroxidation of low density lipoprotein
Evidence of Surface Diffusion of Water Molecules on Proteins of Rabbit Lens by NMR Relaxation Measurements
Authors: Bodurka Jerzy , Buntkowsky Gerd , Gutsze Aleksander
Published: August 2018

In this work, we propose a relaxation model for the interpretation of NMR proton spinlattice and spin-spin relaxation times of mammalian lenses. The framework for this model is based on nuclear magnetic spin-lattice relaxation measurements as a function of tem perature at different Larmor frequencies for whole rabbit lenses and fragments of the lens. According to this model, two different dynamic processes of the water molecules determine the relaxation behaviour, namely rotational diffusion and translational surface diffusion. These dynamic processes in conjuction with a two site exchange model give a good explanation of all the measured relaxation data. From the experimental data, we were able to obtain the activation parameters for rotational and translational diffusion of bound lens water. Correlation times of 2.1×10-11 sec and 2.5×10-9 sec and activation energies of 20.5 kJ/mol and 22.5 kJ/mol respectively were found at 308K. At low Larmor frequencies (≤ MHz) the longitudinal relaxation is mainly determined by translational surface diffusion of bound water with a mean square displacement of 1.5 nm, whereas at higher frequencies (≥300 MHz), rotational diffusion is the main relaxation mechanism. The spin-spin relaxation is determined by translational diffusion over the whole frequency range and therefore shows only a very small dispersion. By our model it is possible to explain: 1) the strikingly large difference between the T1 value and the T2A and T2B values observed in the lens and 2 ) the different values of the activation energies measured at different fields for the lens.
Effect of 2'-Deoxyguanosine Oxidation at C 8 Position on N-Glycosidic Bond Stability
Authors: Bialkowski Karol , Cysewsk Piotr , Olinski Ryszard
Published: August 2018

8-Oxo-2′-deoxyguanosine, 8-Oxoguanine, 8 -Hydroxyguanine, Base Modification, DNA Oxidative Damage The influence of 2′-deoxyguanosine (dG) oxidation at the C-8 position on N-glycosidic bond stability was in­ vestigated. A kinetic analysis of dG and 8-oxo-2′-deoxy-guanosine (8-oxodG) depurination reactions was carried out in water solutions at pH ranging from 2 to 7.4 and temperature of 100 °C. The results indicate that N-glyco­ sidic bond of 8-oxodG is significantly more stable in comparison with dG at any pH applied. At pH 5.1 hy­drolysis rate of dG is 4.5-fold higher than that for 8-oxodG. The chemical stability of the modified nucleo­ side in oxidatively damaged DNA is one of important factors contributing to its mutagenic potential. Results of our experiments indicate that 8-oxodG, potentially mutagenic and carcinogenic nucleoside, is hardly suscep tible to spontaneous depurination and its removal from cellular DNA depends mostly on the activity of DNA repair enzymes.
Structural Role of Carotenoids in Photosynthetic Membranes
Authors: Moskalenko Andrey A , Karapetyan Navassard V
Published: August 2018

Besides the light-harvesting and protecting role, carotenoids are also instrumental as structural components for the assembly of light-harvesting complexes in purple bacteria and green plants, as well as for the formation of photosystem II complex. Carotenoids stabilize those pigm ent-protein complexes, but have no effect on the form ation of the reaction centers of purple bacteria and photosystem I of plants.
Structural Study of Flavonoids and Their Protonated Forms
Authors: Tóth Jaroslav , Remko Milan , Nagy Milan
Published: August 2018

The highly successful semiempirical quantum chemical methods AM1 (Austin Model 1) and PM3 (a reparametrization of AM1) were applied to an investigation of the conformational properties of flavone, 3-hydroxyflavone, isoflavone and 2-hydroxyisoflavone. The most stable structures correspond to the non-planar forms with an angle of phenyl ring rotation out of the chromone moiety from a relatively narrow interval (28° - 38°). The mono- and diprotonation of these compounds was also investigated. The prominent site of protonation is the oxygen of the carbonyl group with a protonation enthalpy from the interval of about 900 -920 kJ.mol-1. The protonation enthalpy for protonation of the ether oxygen was computed to be about 200 kJ.mol-1 lower. Adding a second proton to monoprotonated species studied resulted in much lower protonation enthalpies compared to monoprotonation. The geometry of the studied compounds upon protonation changed considerably.
Inhibition of Betacyanin Accumulation by Abscisic Acid in Suspension Cultures of Phytolacca americana
Authors: Hirano Hiroshi , Sakuta Masaaki , Komamine Atsushi
Published: August 2018

Growth of cells and the accumulation of betacyanin were suppressed by the addition of abscisic acid (ABA) to suspension cultures of Phytolacca americana. The decrease in the accumulation of betacyanin was overcome by exogenously supplied tyrosine which is a precursor of betacyanin. ABA decreased the level of free tyrosine in the cells. Feeding experiments using labeled tyrosine revealed that ABA reduced the incorporation of labeled tyrosine into betacyanins (to about 50% of the control rate). These results suggest that both the availability of tyrosine and the biosynthetic activity of the pathway from tyrosine to the betacyanins are involved in the inhibition of the accumulation of betacyanins by ABA in Phytolacca americana cells.
GC Profiles of Volatile Constituents from Human Urine Obtained by Closed Loop Stripping, Purge and Trap Technique and Simultaneous Steam Distillation-Extraction
Authors: Bestmann Hans Jürgen , Haberkorn Klaus , Vostrowsky Otto , Ferstl Roman , Eggert Frank
Published: August 2018

Different techniques like “closed loop stripping” [CLSA], “purge and trap” [PTI], and continous steam distillation extraction [SDE] were used to establish GC profiles of major histocompatibility complex-associated volatile constituents of human urine and statistically evaluated for reliability. Of the three methods investigated, PTI appeared to be superior for the detection of very volatile substances, whereas SDE was the most efficient one with respect to yield. A number of short to medium-chain ketones, 4-hydroxy-3-methoxy-styrene, menthol and nicotine were identified in preliminary analyses.
Lipids Associated with the (Na+-K+)ATPase Activity of Normal and Denervated Electric Organs of Electrophorus electricus (L.)
Authors: Barriviera M. L , Hasson-Voloch A
Published: August 2018

The effect of denervation on the lipid metabolism and on the activity of (Na+-K+)ATPase isoforms from the membrane fraction P3, which corresponds to the innervated electrocyte membrane, was evaluated. On a discontinuous sucrose gradient, normal P3 membranes exhibit a bimodal (“a” and “b ” bands) distribution of the (Na+-K+)ATPase activity, which upon denervation changes to an unimodal (“c” band) distribution. Using these fractions, which have a higher (Na+-K+)ATPase activity, we characterized the lipids at the hydrophobic protein surface boundary, (i.e., the bulk lipids that surround the protein). The results confirm that these lipids consist of phospholipids and cholesterol. The quantitative composition of the phospholipids is similar for both isoform fractions obtained from the discontinuous gradient of normal membranes, with phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine representing about 90% of the total phospholipids. Sphingomyelin, phosphatidylinositol, diphosphatidylglycerol and phosphatidic acid were in the minority. However, in the single band obtained after denervation, the three major phospholipid components decreased to 70% of the total, and a significant increase in the other phospholipids and in cholesterol was observed. The high cholesterol content of the denervated fraction may confer membrane stabilization, as it is likely to cause a decrease in the membrane fluidity and consequently in the enzyme activity.
24-Epibrassinolide from Gypsophila perfoliata
Authors: Schmidt Jürgen , Böhme Frank , Adam Günter
Published: August 2018

The scarce 24-epibrassinolide could be identified from seeds of Gypsophila perfoliata L. by GC/MS as the only brassinosteroid present. Furthermore, the Δ7-phyto-sterols ergost-7-en-3β-ol, spinasterol and 22-dihydro-spinasterol were found as main sterols in the same plant material.
A Cytotoxic Principle of Tamarindus indica, Di-w-butyl Malate and the Structure-Activity Relationship of Its Analogues
Authors: Kobayashi Akio , Adenarr Mohd Ilham , Kajiyama Shin-ichiro , Kanzaki Hiroshi , Kawazu Kazuyoshi
Published: August 2018

Bioassay-guided fractionation of the methanolic extract of Tamarindus indica fruits led to the isolation of L -(-)-di-nbutyl malate which exhibited a pronounced cytotoxic activity against sea urchin embryo cells. In order to study structure-activity relationships, close-structure relatives of di-n-butyl malate were synthesized using d -(+) -and L -(-)-malic acid as starting materials, and their cytotoxic activities were exam in ed for the sea urchin em bryo assay. L -(-)-D i-n-pentyl malate was the most effective inhibitor to the development of the fertilized eggs. Significant inhibitory activity was not seen in the esters of D -(-)-isomer .
Conformational Changes Involved in the Switch from Ovalbumin to S-Ovalbumin
Authors: Castellano Agostina Congiu , Barteri Mario , Bianconi Antonio , Bruni Fabio
Published: August 2018

For the first time a comparative study on conformational differences between native oval­ buminand its heat-stable form, called S-ovalbumin. using small angle x-ray scattering, is reported. To detect a different pathway in the folding mechanism of the two proteins, scatter­ing measurements have been performed on ovalbumin and S-ovalbumin denatured with dif­ferent concentrations of guanidine hydrochloride, and by heating the proteins at acid pH. The intensity scattering curves provide evidence that the intermediate states in the unfolding process are globular for both proteins while their compactness changes. The reported experi­mental results suggest that the ovalbumin to S-ovalbumin transformation can be considered a protein-switch triggered by changes in the chemical conditions of the protein environment. Because the conformational changes are likely to be of functional importance, we infer that the occurrence in vivo of S-ovalbumin is thus determined by the transformation of ovalbumin, with a functional role for embryonic development, into a new protein with a dif­ferent function.
Altered Fatty Acid, Cholesterol and Na+/K+ ATPase Activity in Erythrocyte Membrane of Rheumatoid Arthritis Patients
Authors: Masoom-Yasinzai M.
Published: August 2018

Rheumatoid Arthritis, Cholesterol, Eicosapentaenoic Acid. Na+/K+ ATPase, Erythrocyte Membrane Rheumatoid arthritis (RA) is a chronic inflamatory disease whose cause remains obscure. Blood from 15 R A patients and controls was taken and their ghosts separated. The ghosts were analysed for cholesterol content, Na+/K+ ATPase activity and eicosapentaenoic acid. The cholesterol content in the ghosts of RA patients was significantly lower as compared with the set of controls. There was a major difference in the activity of Na+/K+ ATPase between the two groups with RA patients showing significantly elevatad activity. The ghosts of the RA patients exhibited major abnormality in the polyunsaturated fatty acids of phos­pholipids with the level of eicosapentaenoic acid (ω-3, 20:5) being significantly reduced.
Aspects of the Cell Growth of Candida guilliermondii in Sugar Cane Bagasse Hydrolysate
Authors: Molwitz M. , Silva S.S. , Ribeiro J.D. , Roberto I.C. , Felipe M.G.A. , Prata A.M.R. , Mancilha I.M.
Published: August 2018

In this work the behavior of the growth of Candida guilliermondii FTI 20037 in sugar cane bagasse hemicellulosic hydrolysate on various oxygen transfer rates was investigated. The yeast was able to grow and produced xylitol at different performence levels. At 1.0 vvm (volume of air per volume of medium per minute) the highest growth with 24.4 g/g was observed, but no xylitol was produced. At aeration rate of 0.5 vvm the growth was lower, but therefore slight amounts of xylitol (xylitol yield factor - Yp/s = 0.15 g/g) were observed. The lowest cell concentration (10.7 g/l) and the highest xylitol yield (Yp/s = 0.46 g/g) was observed when aeration was changed from 0.5 vvm to 0.05 vvm after 14 h.
Diadenosine 5′,5‴- P1,P4-tetraphosphate (Ap4A) Hydrolase from Tomato (Lycopersicon esculentum cv. Lukullus) -Purification, Biochemical Properties and Behaviour during Stress
Authors: Feussner Kirstin , Guranowski Andrzej , Kostka Susanne , Wasternack Claus
Published: August 2018

Dinucleoside 5′,5‴-P1,P4-tetraphosphate hydrolase (EC 3.6.1.17) has been purified to homogeneity from tomato (Lycopersicon esculentum) cells grown in suspension. The purification procedure comprised ammonium sulphate fractionation following five standard chroma­ tography steps and a final chromatography on Ap4A-Sepharose.

The homogeneous hydrolase has a molecular mass of 20 kD a and an isoelectric point of 4.5. The enzyme hydrolyses diadenosine tetraphosphate (Ap4A) asymmetrically to AMP and ATP. Among other naturally occurring dinucleoside oligophosphates, Ap5A and Ap6A are substrates whereas Ap3A is not. Of various phosphonate analogues tested, the Ap5A analogue, AppCH2pCH2ppA, was not cleaved and the Ap3A analogue, ApCH2CH2ppA. was a very poor substrate. Enzyme activity is stimulated by 5mм Mg2+ and inhibited by fluoride anion; I50 = 6.25 μм . The Km value for Ap4A is 0.8 μм . The enzyme exhibits a broad pH optimum from pH 6.5 to 9.0. In order to analyze the protein at the molecular level an internal peptide sequence from the homogeneous enzyme was identified. Within the sequence of 17 amino acids a kinase II motif as a general part of a conserved sequence of nucleotide binding sites was found.

Against the internal peptide sequence a polyclonal antiserum was raised. By investigating the intracellular level of Ap4A hydrolase under different kinds of environmental stress, no changes occurred in response to heat shock. But, heavy metal stress and phosphate deprivation lead to a decrease in Ap4A hydrolase.
Ca2+ Uptake Coupled to Glycogen Phosphorolysis in the Glycogenolytic-Sarcoplasmic Reticulum Complex from Rat Skeletal Muscle
Authors: Nogues M. , Cuenda A. , Henao F. , Gutiérrez-Merino C.
Published: August 2018

The glycogenolytic-sarcoplasmic reticulum complex from rat skeletal muscle accumulates Ca2+ upon stimulation of glycogen phosphorolysis in the absence of added ATP. It is shown that an efficient Ca2+ uptake involves the sequential action of glycogen phosphorylase, phosphoglucomutase and hexokinase, which generate low concentrations of ATP (approximately 1 -2 μм) compartmentalized in the immediate vicinity of the sarcoplasmic reticulum Ca2+, Mg2+-ATPase (the Ca2+ pump). The Ca2+ uptake supported by glycogenolysis in this subcellular structure is strongly stimulated by micromolar concentrations of AMP, showing that the glycogen phosphorylase associated with this complex is in the dephosphorylated b form. The results point out that the flux through this compartmentalized metabolic pathway should be enhanced in physiological conditions leading to increased AMP concentrations in the sarcoplasm, such as long-lasting contractions and in ischemic muscle.
Topical Anti-Inflammatory Lignans from Haplophyllum hispanicum Haplophyllum hispanicum
Authors: Prieto J. M. , Recio M. C. , Giner R. M. , Máñez S. , Massmanian A. , Waterman P. G. , Ríos J. L.
Published: August 2018

The present paper reports the results of the methanol extract of Haplophyllum hispanicum Spach on single or repeated local 12-O-tetradecanoylphorbol acetate (TPA) administration and in the oxazolone-induced contact-delayed hypersensitivity mouse ear edemas. Two topical anti-inflammatory aryl naphthalide lignans were isolated from the active fractions of the methanol extract. They were identified by spectroscopic methods, including 13C NMR and heteronuclear multiple bond correlation (HMBC), as diphyllin acetyl apioside and tuberculatin. The former was the most active on acute TPA edema with a ID50 of 0.27 μmol/ear
Cepaciachelin, A New Catecholate Siderophore From Burkholderia (Pseudomonas) Cepacia ***
Authors: Barelmann I. , Meyer J.-M. , Taraz K. , Budzikiewicz H.
Published: August 2018

In addition to the known hydroxamate siderophores ornibactin C6 and C8 a catecholate siderophore named cepaciachelin, 1-N-[2-N′,6-N′-di(2,3-dihydroxybenzoyl)-ʟ-lysyl]-1,4-diaminobutane, was isolated from a Burkholderia (Pseudomonas) cepacia PHP7 culture and its structure elucidated by chemical degradation and spectroscopic methods. This is the first case of a member of the Pseudomonas group which produces both hydroxamate and catecholate siderophores
Convective Gas Flow in Plant Aeration and Graham's Law of Diffusion
Authors: Schiwinsky Klaus , Grosse Wolfgang , Woermann Dietrich
Published: August 2018

Experiments with porous ceramic membranes and leaves of Nymphaea alba L. are described which demonstrate that the counter diffusion of gaseous components of different molar mass governed by Graham’s law of diffusion (not to be confused with Graham’s law of effusion) has to be taken into account to understand the exchange processes of gases between leaves of aquatic and amphibic plants and the outer atmosphere. The experiments are carried out under conditions under which the ratio of the maximum pore size r of the ceramic material to the mean free path length λ. of the molecules in air has a value of the order of λ/r ≈ 1
Inhibition of the Photosynthetic Electron Transport by Pyrethroid Insecticides in Cell Cultures and Thylakoid Suspensions from Higher Plants
Authors: Bader Klaus P. , Schüler Judith
Published: August 2018

Synthetic pyrethroid insecticides with different molecular structures have been investigated with respect to their effect on photosynthetic electron transport reactions in chloroplast suspensions and cell cultures from higher plants. The fluorescence induction curves of tobacco (Nicotiana tabacum) leaves and tomato cells were substantially affected by permethrin and cypermethrin resulting in a strong increase of the maximum fluorescence. Application of different concentrations (0.3-1.2 mᴍ ) of the respective chemical abolishes virtually any kinetics of the normal Kautsky effect. Oxygen evolution from cell cultures from tomato (Lycopersicon peruvianum) was completely inhibited by cypermethrin. Analysis of partial reactions of the photosynthetic electron transport showed that both a methylviologen-mediated Mehler reaction and a ferricyanide-driven Hill reaction were quantitatively inhibited by e.g. fenvalerate. On the other hand, neither a silicomolybdate-driven Hill reaction nor a methylviologen- driven Mehler reaction using dichlorophenol indophenol/ascorbate as electron donors could be inhibited by the pyrethroid. The analyses suggest that pyrethroid insecticides interfere with the photosynthetic electron transport at the same site as urea-type herbicides do. Depending on the molecular structure and on the halogen compound in the molecule, however, different pyrethroids are more or less phytotoxic to the investigated photosynthetic membranes - cypermethrin with two Cl-substituents requires much higher concentrations to be applied for significant inhibition of the electron transport reactions than the Br-derivative deltamethrin does. Moreover, qualitative differences have to be taken into account. In the case of fenvalerate the effect seems to exist in a type of all-or-nothing reaction when the reaction centres are inhibited by the pyrethroid. None of the S-states nor the transition probabilities are specifically influenced by increasing concentrations of fenvalerate. In the case of deltamethrin, however, it was found that the overreduced state S-1 is significantly increased at the expense of both S1 and S0. Moreover, the miss parameter a is increased in the case of deltamethrin addition. The results and the significance of different substituents for the investigated pyrethroids are discussed
Aseptic Dual Culture of the Aphid Chaitophorus salijaponicus with Different Tissues of Salix Hosts
Authors: Krekeler Beatrice , Beiderbeck Rolf
Published: August 2018

The apterous generation of the viviparous aphid Chaitophorus salijaponicus was propagated aseptically on in vitro cultures of host shoots for more than 34 passages and 17 months. On the best suited host (Salix alba) a single nymph yielded a colony of 126.3 ± 24.4 individuals within 4 weeks. Other tissues than normal host shoots (callus, root cultures, fasciated shoots) did not support aphid propagation. Aphid colony development accelerated the senescence of host shoots and severely inhibited the development of adventitious root systems. The aspects of insect surface sterility, aphid colony development and its influence on the host are discussed
Three Further Dammarane Type Triterpenes from the Frond Exudate of the Fern Notholaena rigida
Authors: Arriaga Fco. Javier , Rumbero Angel , Wollenweber Eckhard
Published: August 2018

From the farinose frond exudate of the fern Notholaena rigida two new triterpenes have been identified. They were found to be the C-24 epimers of 3β-acetoxy- 24, 25-diO-isopropylidene-12β, 20(S),24,25-tetrahydroxy- dammarane. A third triterpene is identical with the known compound pyxinol, (20S,24R)-20.24-epoxydammarane- 3β,12β,25-triol
Erythrocyte Hemolysis by Organic Tin and Lead Compounds
Authors: Kleszczyńska H. , Hładyszowski J. , Przestalski S.
Published: August 2018

The effect of trialkyllead and trialkyltin on pig erythrocyte hemolysis has been studied and compared. The results of experiments showed that the hemolytic activity of organoleads increases with their hydrophobicity and follows the sequence: triethyllead chloride < tri-npropyllead chloride < tributyllead chloride. And similarly in the case of organotins: triethyltin chloride < tri-n-propyltin chloride < tributyltin chloride. Comparison of the hemolytic activity of organoleads and organotins indicates that the lead compounds exhibit higher hemolytic activity. The methods of quantum chemistry allowed to determine the maximum electric potential of the ions R3Pb+ and R3Sn+, and suggest a relationship between the potential and toxicity.
Non-Enzymatic, Low Temperature Fluorescence in situ Hybridization of Human Chromosomes with a Repetitive α-Satellite Probe
Authors: Durm Markus , Haar Frank-Martin , Hausmann Michael , Ludwig Horst , Cremer Christoph
Published: August 2018

In all DNA-DNA in situ hybridization (ISH) procedures described so far in the literature, the production of single-stranded target DNA sequences plays a decisive role. This can be achieved either by enzymatic treatment at physiological temperatures or by the separation of double-stranded DNA sequences. Denaturation by heat and chemical agents (e.g. formamide) is regarded as a prerequisite for the non-enzymatic ISH process. However, additional mechanisms of a non-enzymatic ISH procedure are conceivable which do not require high temperature treatment combined with formamide. Here, we report on a non-enzymatic, non-formamide, low temperature, fluorescence in situ hybridization (FISH) procedure which allowed a microscopic visualization and quantitative fluorescence analysis of the binding sites of a repetitive DNA probe. Following only probe denaturation at 94 °C, hybridization was performed at 52 °C for 30 min, i.e., at nearly physiological temperatures. Moreover, increasing the hybridization time to 3 hours indicated that hybridization sites became also visible at 37 °C. Since the protocols are based on recently described Fast FISH developments, the technique will be called Low Temperature Fast-FISH (LTFF).
A Visually Induced Switch in Mode of Locomotion of a Spider
Authors: Schmid Axel
Published: August 2018

The spider Cupiennius salei Keys. (Araneae, Ctenidae) is a nocturnal hunter living on monocotyledones. It does not build webs for prey capture. During the day it remains in its retreat and during dusk it begins to hunt for prey or to search for mates. C. salei is well equipped with mechanosensory systems to detect air- or substrate- borne vibrations elicited by prey or predators. If none of them produce either air movements or substrate vibrations, and the light intensity is below the threshold (0.1 lx), the animal is virtually " blind" . There­ fore a hypothetical, additional sensory input should exist, which is used only in complete darkness. The animal was tested on a locomotion compensator were it performs constant walks towards a visual target. Three different light intensities were used (bright 200 lx, dim 0.1 lx, and dark at 950 nm, which is outside the spectral sensitivity range of the animal). At bright and dim illumination the animal walked in the alternating tetrapod gait towards the target. In complete " darkness" the walk was no longer directed and the animal changed its gait and continued walking on only six legs using the first pair as guide-sticks. If the first pair is missing, the second cannot replace this function. This shows a twofold use of the first pair o f legs as ordinary walking legs and as guide-sticks or " antennae" . Therefore one can assume that visual input causes a behavioral change, which can not be explained by a fixed locomotion pattern but by adaptive changes caused by visual inputs.
Induction of Hydroxycinnamoyl-CoA: Hydroxyanthranilate N-Hydroxycinnamoyl- transferase (HHT) Activity in Oat Leaves by Victorin C
Authors: Ishihara Atsushi , Matsukawa Tetsuya , Miyagawa Hisashi , Ueno Tamio , Mayama Shigeyuki
Published: August 2018

Victorin C, a host-specific toxin produced by Helm inthosporium victoriae, induced hydro-xycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyltransferase (HHT, EC 2.3.1) ac­tivity in oat leaves (Avena sativa L., a cultivar carrying Pc-2 gene). This enzyme activity catalyzes the final step of biosynthesis of oat phytoalexins, avenanthramides. The HHT activ­ity was detected after 12 h of victorin C application and reached to a maximum by 18 h. The induction of HHT was dose-dependent. All of the putative precursors of avenanthramides acted as substrates for HHT. These findings indicate that the accumulation of avenanthram ­ ides by victorin C treatment is due to induction of HHT. The enzyme activity showed highest specificity to 5-hydroxyanthranilate for the anthranyl moiety, while feruloyl-CoA was most effective for cinnamoyl moiety. HHT induced by victorin C showed significantly lower affinity for anthranilic acid relative to the enzyme induced by oligo-N-acetylchitooligosaccharides, another elicitor, suggesting that isozymes of HHT occur in this plant.
4-Pentadecylpyridine: A Competitive Polyphenoloxidase Inhibitor
Authors: Fuchs Claus T. , Spiteller Gerhard
Published: August 2018

4-Pentadecylpyridine was isolated from plums infected by Taphrina pruni. This fungal metabolite has been tested for its effect on polyphenoloxidase, using the polyphenoloxidase-catalysed addition of L-proline to 4-methylcatechol in a chromogenic assay The resulting data prove that 4-pentadecylpyridine is a competitive inhibitor to polyphenoloxidase with an inhibitor constant of 3.70 ± 0.03×10-4 м . Further comparative measurements have demon­strated that the effect is due to the pyridine moiety. Probably reduced polyphenoloxidase-activity decreases the toxicity of o-diphenols to the fungus and thus increases susceptibility of plums to the fungus Taphrina pruni.
UDP-Glucose: Flavonol 7-O-glucosyltransferase Activity in Flower Extracts of Chrysanthemum segetum
Authors: Stich K. , Halbwirth H. , Wurst F. , Forkmann G.
Published: August 2018

The yellow colour of Chrysanthemum segetum petals is due to the presence of the 7-O-glucosides of quercetin and particularly gossypetin (8-hydroxyquercetin). In petal extracts of C. segetum an enzyme was demonstrated which catalyzes the transfer of the glucosyl moiety of uridine 5'-diphosphoglucose (UDPG) to the 7-hydroxyl group of flavonols with gossypetin and quercetin as the best substrates. Besides flavonols flavanones and flavones were found to be glucosylated in the 7-position. The pH-optimum of the reaction highly depended on the substrate used. With quercetin as substrate, maximal enzyme activity occurred at a pH of 8.25 and a temperature of 25 °C, but 7-O-glucosylation also proceeded at low temperatures. Studies on temperature stability revealed, that there was no influence on the glucosylation reaction up to 40 °C. Higher temperatures led to a loss of enzyme activity. Using gossypetin as a substrate a similar course of temperature stability was observed. Addition of Mg2+, Ca2+ and KCN slightly stimulated 7-O-glucosylation, whereas Co2+, Cu2+, Fe2+, Hg2+, p-hydroxymercuribenzoate and N-ethylmaleimide showed a strong inhibitory effect. Additional enzymatic studies were performed with the commercial strain " Stern des Orients" where gossypetin 7-O-glucoside is restricted to the inner parts of the petals. For enzyme extracts from both parts of the petals gossypetin was found to be the most attractive substrate. In comparison to quercetin (133.4 μkat / kg protein) an about three times higher specific activity of the 7-O-glucosyltransferase(s) was determined with gossypetin (382.1 μkat/ kg protein) as substrate, indicating that hydroxylation of quercetin in 8-position to gossypetin precedes 7-O-glucosylation.
Enzymatic and Electrochemical Reactions of Xanthine Oxidase Immobilized on Carbon Materials
Authors: Horozova E. , Dimcheva N. , Jordanova Z.
Published: August 2018

An optimum way of immobilizing xanthine oxidase on graphite was found where a redox transformation of the enzyme was observed. The nature of the redox maxima was hypothe­ sized on the basis of the dependence of the half-wave potential (Ep/2) on the pH of the solution. The enzymatic activity of xanthine oxidase adsorbed on two kinds of soot was studied by the oxidation of xanthine. The kinetic and activation parameters of the enzyme reaction were determined.
Characterization and Cloning of Cutinase from Ascochyta rabiei
Authors: Tenhaken Raimund , Arnemann Martin , Köhler Gabriele , Barz Wolfgang
Published: August 2018

Ascochyta rabiei, the causal agent of Ascochyta blight on chickpea plants, secretes a cutinase in the culture filtrate when it is induced by cutin or hydroxylated fatty acids. This cutinase is the main esterase in the culture fluids. The enzyme was purified to homogeneity by three successive chromatographic steps. It showed an apparent molecular weight of 22 kD in SDS-PAGE and cleaved ester bonds of 3H-labelled cutin or p-nitrophenylbutyrate with maximal activities around pH 8. As a serine esterase, cutinase is strongly inhibited by organophosphorous compounds and the most effective inhibitor 2,3,5-trichloropyridine-6-(0-methyl-O-n-butyl)-phosphateester (MAT 9564) shows a K1 value of 0.8 nᴍ. The cutinase gene was cloned from a genomic cosmid library by screening with two oligonucleotides directed against cutinase consensus peptides. The gene was subcloned to a 1.7 Kb Sa1l/Hindlll-insert and sequenced. The cutinase gene codes for a 223 amino acid protein with strong homology to other fungal cutinase sequences. The purified cutinase is encoded by a single copy gene.
Role of Hydrophobic and Hydrophilic Interactions of Organotin and Organolead Compounds with Model Lipid Membranes
Authors: Gabrielska Janina , Sarapuk Janusz , Przestalski Stanisław
Published: August 2018

The present study was conducted to clarify the mechanism of toxicity of organic compounds using lipid model membranes (liposomes and planar lipid membranes).

The compounds studied were trialkyltin and trialkyllead chlorides, dialkyltin dichlorides and some inorganic forms of those metals. Two different (anionic and cationic) detergents were also used in the experiments to change the surface properties of liposomes. As a measure of interaction between the compounds studied and model membranes were the release of liposome bound praseodymium and the change in stability of planar membranes under the influence of those compounds.

On the basis of the results obtained it was postulated that the mechanism of interaction between tin-and leadorganics and model lipid membranes is a combination of different factors featuring interacting sides. The most important properties determining the behaviour of organic compounds in the interaction were lipophilicity and polarity of different parts of the organics and the steric arrangement they can take in the medium. On the other hand, the surface potential of the lipid bilayer and the environment of the lipid molecules, that play a significant role in the availability of the lipid bilayer to the organics, were important factors in the interaction.
Serological Characterization of Hungarian Plum Pox Virus Isolates
Authors: López-Moya Juan José , López-Abella Dionisio , Díaz-Rúiz José-Ramón , Martinez-Garcia Belén , Gáborjányi Richard
Published: August 2018

Three Hungarian (No.2, 4 and 9), and a Moldavian (K) plum pox virus isolates were compared with a characterized Spanish isolate (5.15) by RT-PCR, ELISA, dot-blot and West­ern blot analysis. Monoclonal antibodies prepared against the external, intermediate and internal sequences of the coat protein of the Spanish isolate were able to differentiate the four isolates. Hungarian isolate No. 2 proved to be serologically identical to the Spanish isolate, while No. 4 showed appreciable differences and No. 9 could be recognized only by the monoclonal antibodies representing the intermedial and internal parts of the coat protein. K isolate showed a more distant relationship to other isolates. Our experiment provided the first demonstration of the presence of D type isolates in Hungary.
Phenolics from Cell Suspension Cultures of Penstemon serrulatus; Relation to Plant Organs
Authors: Skrzypek Zuzanna , Wysokińska Halina
Published: August 2018

By repeated selection of pigment portions of tissue the red callus induced from root seed­lings of Penstemon serrulatus Menz. was chosen for suspension culture, which was maintained in Schenk and Hildebrandt medium supplemented with naphthaleneacetic acid (0.2 mg/l), 6-benzylaminopurine (2 mg/l) and sucrose (50 g/l). From the cultured cells eight phenolic compounds were isolated. They were identified as cyanidin 3-O-glucoside, delphinidin 3-O-glucoside, luteolin, luteolin 7-O-glucoside, norartocarpetin 7-O-glucoside, verbascoside, martynoside and leucosceptoside A. The kind of cell line, its age and light irradiation were important factors in flavonoid production, but production of phenylpropanoid glycosides was found to be unaffected by these factors. The phenolic composition found in the cell culture was compared with those in the flowers and leaves of original plants of P. serrulatus.
Nonphotochemical Quenching of Chlorophyll Fluorescence in Higher Plant Leaves Studied by Delayed Fluorescence Decay Measurements
Authors: Terjung Frank , Maier Karlheinz
Published: August 2018

Delayed chlorophyll fluorescence decay measurements on the second time scale were applied to investigate the state of photosystem II under different photosynthetic conditions. Leaves adapted to high and low light intensities were used to study the effects of nonphotochemical quenching (energy quenching) on the photosynthetic state. 3-(3,4-dichlorophenyl)- 1,1-dimethylurea (DCM U)-treated leaves were used to characterize the photosynthetic state in the absence of a transthylakoid ApH, dithiothreitol (DTT)-treated leaves in the absence of the xanthophyll zeaxanthin. The fast decay components were the most affected by energy quenching as indicated by increased decay times. The slowest decay component was hardly affected, neither in amplitude nor in decay time. The measurements indicate a relaxation of energy quenching on the second time scale and the absence of damages in the electron transfer chain of PS II. The constant decay times of the DTT-treated leaf, comparable to those of the DCMU-treated leaf, indicate the obligatory role of zeaxanthin for most of the detected energy quenching.
Does Astaxanthin Protect Haematococcus against Light Damage?
Authors: Fan Lu , Vonshak Avigad , Zarka Aliza , Boussiba Sammy
Published: August 2018

The photoprotective function of the ketocarotenoid astaxanthin in Haematococcus was questioned. When exposed to high irradiance and/or nutritional stress, green Haematococcus cells turned red due to accumulation of an immense quantity of the red pigment astaxanthin. Our results demonstrate that: 1) The addition of diphenylamine, an inhibitor of astaxanthin biosynthesis, causes cell death under high light intensity; 2) Red cells are susceptible to high light stress to the same extent or even higher then green ones upon exposure to a very high light intensity (4000 μmol photon m-2 s-1); 3) Addition of 1O2 generators (methylene blue, rose bengal) under noninductive conditions (low light of 100 (μmol photon m-2 s-1) induced astaxanthin accumulation. This can be reversed by an exogenous 1O2 quencher (histidine); 4) Histidine can prevent the accumulation of astaxanthin induced by phosphate starvation. We suggest that: 1) Astaxanthin is the result of the photoprotection process rather than the protective agent; 2) 1O2 is involved indirectly in astaxanthin accumulation process.