bluuebunny/crossref_metadata_2025 huggingface dataset:
Uptake and Exudation of Phenolic Compounds by Wheat and Antimicrobial Components of the Root Exudate
Authors: Kobayashi Akio , Kim Myong Jo , Kawazu Kazuyoshi
Published: August 2018

In the course of our study, it was found that phenyl propenoic acid derivatives were readily taken up by wheat. Leaf leachate components were chosen for the feeding experiments and p-coumaric acid, ferulic acid and caffeic acid were found to be quickly taken up into the plants via the roots. The analytical study revealed that the exudate contained potent antimicrobial compounds together with amino acids and sugars.

Besides the primary metabolites, 4-hydroxystyrene, 3-methoxy-4-hydroxystyrene and 3-methoxy-4-acetoxystyrene were identified as exudate components from wheat roots in sterile hydroponic culture. This indicates that these antimicrobial components may play a significant role in the defense system as allelochemicals for the rhizosphere.
Effects of Potassium-(picrate)-(18-crown-6) on the Photosynthetic Electron Transport
Authors: Kovács L. , Hegde U. , Padhye S. , Bernát G. , Demeter S.
Published: August 2018

The effects of potassium-(picrate)-(18-crown-6) on the electron transport of photosystem II was investigated in isolated pea thylakoids. Low concentrations of the compound inhibited the fast decay of fluorescence yield associated with electron transfer between the primary (QA) and secondary (QB) quinone electron acceptor and increased the intermediary level of fluorescence to the Fmax level. The decay half-time of fluorescence yield measured in the presence of DCMU(S2QA
- charge recombination) decreased from about 1.8 s to about 0.3 s in thylakoids treated with potassium-(picrate)-(18-crown-6). While the inhibition of electron transport by DCMU gave rise to the appearance of a thermoluminescence band at about + 10°C (S2QA
- charge recombination) addition of potassium-(picrate)-(18-crown-6) resulted in a thermoluminescence band at about -10°C. Increasing concentrations of potassium-(picrate)-(18-crown-6) diminished the fluorescence yield and the -10°C TL band and abolished the Signal IIS and Signal IIf EPR signals of the tyrosine-D and tyrosine-Z electron donors, respectively. The phenolic-type inhibitor, potassium picrate had the same effect on thermoluminescence and on the tyrosine EPR signals. It is concluded that potassium-(picrate)-(18-crown-6) is a phenolic type inhibitor owing to its picrate constituent. At low concentrations picrate and potassium-(picrate)-18-crown) not only block the electron transport between QA and QB but they probably decrease the midpoint redox potential of QA, as well. At high concentrations they also inhibit the light-induced oxidation of the tyrosine-D and tyrosine-Z donors.
Inhibitors of Chlorophyll Biosynthesis from Bulbs of Gladiolus spp.
Authors: Wübert Joachim , Oster Ulrike , Rüdiger Wolfhart
Published: August 2018

Compounds extracted with methanol from the bulbs of Gladiolus spp. were tested for inhibition of Chl accumulation in greening cress (Lepidium sativum L.) seedlings. For the biotest, cress seeds were imbibed with water for 8 h and then incubated in the dark with the test solution for 40 h. Chlorophyll accumulation was determined at the end of the subsequent irradiation period of 8 h. Compounds active in this biotest were purified by several chromato­ graphic steps and identified by thin-layer chromatography with staining reactions and by gas chromatography/mass spectrometry. The following compounds were identified and their concentration for 50% inhibition of Chl accumulation determined: sucrose (75 mм) plus glucose (30 mм) , 3-hydroxybenzoic acid methylester (0.49 mм) and 5-hydroxymethylfurfural (6.7 mм) . The inhibitory action was compared with several substituted derivatives of the natural compounds.
Coumarins and Iridoids from Crucianella graeca, Cruciata glabra, Cruciata laevipes and Cruciata pedemontana (Rubiaceae)
Authors: Mitova Maya Iv. , Anchev  , Panev Stefan G. , Handjieva Nedjalka V. , Popov Simeon S.
Published: August 2018

The coumarin and iridoid composition of Crucianella graeca, Cruciata glabra, Cruciata laevipes and Cruciata pedemontana has been studied. Daphnin and daphnetin glucoside dominated in C. glabra along with low concentrations of daphnetin, deacetylasperulosidic acid and scandoside. In C. laevipes and C. pedemontana were found the same coumarin glucosides along with six iridoid glucosides. In Crucianella graeca were found ten iridoid glucosides
Accumulation of Chlorophyll and Essential Oils in Photomixotrophic Cell Cultures of Citrus sp
Authors: Reil Gerold , Bergerh Ralf Günter
Published: August 2018

Heterotrophically or photomixotrophically initiated callus cultures of Citrus paradisi, C. limon and C.aurantifolia were grown on different nutrient media and under different light regimes. Calli of C.paradisi that contained > 140 mg chlorophyll per kg wet weight accumulated about 40 volatile mono- and sesquiterpene hydrocarbons, oxigenated terpenes and aliphatic aldehydes. Upon five subcultivations the best yielding callus contained about 5% (186 mg × kg-1 wet wt) of the volatiles found in peel tissue (exo/mesocarp section), and about the twentyfold amount of that found in the fleshy endocarp. The composition of the essential oils from most of the cell cultures equalled grapefruit peel oil, but was shifted to a more fruit flesh-like composition, after the concentration of gellan gum in the medium was increased from 3 to 9 g per L. C.limon produced 11 monoterpenes and n-nonanal (40 mg × kg-1 wet wt max.), and C.aurantifolia yielded limonene only (4.4 mg × kg-1 wet wt max.). For all of the indicated species chlorophyll content and accumulation of volatiles were positively correlated. Addition of exogenous valencene to suspended cells of C.paradisi led to a stable concentration of the conversion product nootkatone. This stably maintained level suggested that a decreased catabolism of available carbon sources might have accounted for the significant accumulation of essential oil constituents
Action of an Antiserum to a-Tocoquinone on Photosystem II-Particle Preparations of N icotiana tabacum
Authors: Schmid G. H. , Radunz A. , Bader K. P. , Myśliwa-Kurdziel B. , Strzałka K. , Kruk J.
Published: August 2018

An antiserum to α-tocoquinone was prepared by immunization of rabbits. Immunization was obtained by injection of a conjugate consisting of the hapten α-tocoquinone attached to methylated ovalbumin into the rabbit. The antiserum recognizes the 3,4-dimethyl-p-benzoquinone group of the molecule as well as part of the immediate vicinity to the side chain. This is concluded from the fact that the antibody has some affinity also to plastoquinone. No reaction of the antibody is observed with α-tocopherol hydroquinone or α-tocopherol. Reaction of the antiserum to α-tocoquinone with photosystem Il-particle preparations from tobacco affects the functionality of the preparation. Chlorophylla-fluorescence emission is quenched without an alteration of the emission spectrum. Concomitant with this fluorescence quenching, the lifetime of two fluorescence components namely that of a fast and a slower component are shortened. By analogy with the literature the fast component is associated with chlorophylla of the reaction center core and that of the slow component with the antenna system in which the lifetime parameter is shortened by the antibody from 3.42 ns to 1.795 ns. The action on the fast component is less and leads to a shortening of the lifetime parameter from 0.373 ns to only 0.249 ns. The effect is interpreted in terms of an enhancement of linear photosynthetic electron transport possibly due to an inhibition of the cyclic electron transport around PS II, discovered by Gruszecki et al. (1995), Z. Naturforsch. 50c, 61 -68
Anticomplement Activity of Lysine Complexes of Propolis Phenolic Constituents and Their Synthetic Analogs
Authors: Georgieva P. , Ivanovska N. , Bankova V. , Popov S.
Published: August 2018

Several phenolic constituents of propolis and their synthetic analogs were derivatized with ʟ-lysine. The ability of these complexes to alter complement activity was estimated in vitro in human serum. The influence of selected complexes on C3 hemolytic activity via classical pathway (CP) and alternative pathway (AP) and on zymosan-induced AP activation was determined. The results suppose that the anticomplement effect of the complexes might be related to the interaction with C3 complement component.
Binding and Uptake of 125Iodine-Labelled, Oxidized Low Density Lipoprotein by Macrophages: Comparism of the Effects of a-Tocopherol, Probucol, Pyridoxal-5'-phosphate and Magnesium-pyridoxal-5'-phosphate-glutamate
Authors: Selmer Daniela , Senekowitsch-Schmidtke Reingard , Schneider W. , Elstner E. F.
Published: August 2018

Specific and unspecific binding and uptake (internalization) by macrophages of 125iodine -labelled, copper-oxidized human low density lipoprotein is differently influenced by the anti­ oxidants α-tocopherol (α-Toc), probucol (Prob), pyridoxal-5'-phosphate (PP) and the magnesium-pyridoxal-5'-phosphate glutamate complex (MPPG). Binding as well as internalization, mediated by the so-called "scavenger receptor" is lower in the presence of MPPG whereas both specific binding and internalization are enhanced. The comparison of the effects in vitro allows a rating of the potentially anti-atherogenic and thus protective effects of the tested substances as follows: MPPG > PP > α-Toc > Prob.
Trichloroacetate Affects the Redox Active Tyrosine 160 of the D2 Polypeptide of the Photosystem II Core
Authors: Li R. , Lin N. , Xu C. , Shen Y. , Govindjee
Published: August 2018

Trichloroacetate (TCA) affects the redox property of YD (tyrosine-160 on D2 polypeptide) after the removal of 33 kDa extrinsic polypeptide from the photosystem II (PSII) core. However, TCA has no obvious effect on the redox property of YZ , confirming that the environments around YZ and YD are quite different. The conclusion on the effects on YD is based primarily on the observation that Y D
+ is not detected as the EPR signal IIslow when 33 kDa polypeptide is released by TCA -treatment. Dialysis of the TCA -treated sample that allows the rebinding of mostly 33 kDa polypeptide restores Y D+, showing that the loss of the EPR signal IIslow| takes place after the removal of 33 kD a polypeptide but not the release of manganese (Mn). Additionally, treatment of several halogenated acetates on Tris-washed PSII particles shows that the degree of their effects on suppressing EPR signal IIslow is correlated with their hydrophobicity. It is postulated that Y D becomes more accessible to some small hydrophobic molecules depending upon their hydrophobicity when 33 kDa poly­peptide is removed.
Magnesium Chelatase of Hordeum vulgare L. Is Not Activated by Light but Inhibited by Pheophorbide
Authors: Pöpperl Gerhard , Oster Ulrike , Bios Inge , Rüdiger Wolfhart
Published: August 2018

The enzyme activity of magnesium chelatase was determined in intact etioplasts of barley (Hordeum vulgare L.) seedlings. Irradiation of isolated plastids with white light for 15 min does not lead to any activation of the enzyme but to a decrease in activity, especially in etioplasts. The enzyme was inhibited by chlorophyllide and zinc pheophorbide only to a certain extent. Strong inhibition was observed with the metal-free pheophorbide (Ki = 0.92 μM) but not with pheophytin or chlorophyll. Penetration of chlorophyllide through the envelope membrane was confirmed by the chlorophyll synthase reaction that occurs in the inner membranes of etioplasts and chloroplasts. The possible role of inhibition of magnesium chelatase by pheophorbide in senescent leaves and tetrapyrrole transport across the plastid envelope are discussed.
Photodynamic Action of Hypericin on Cyanobacteria, Synechocystis and Synechoccus (Anacystis nidulans)
Authors: Brody Seymour Steven , Papageorgiou George , Alygizaki-Zorba Katerina
Published: August 2018

The photodynamic action of hypericin on photosynthesis and respiration were monitored in Synechocystis sp PCC 6803 and Synechoccus ATCC 6311 (Anacystis nidulans). An oxygen electrode was used to measure net oxygen evolution or consumption. The amount of hypericin required to inhibit photosynthesis was quantitively determined. Photosynthesis was completely inhibited in Synechocystis when the molar ratio of chlorophyll/hypericin was about 70:1. Higher concentrations of hypericin did not stop the uptake of oxygen, but rather stimulated the process in the light. Hypericin was readily washed out of the cells forming no permanent associations in the bacterial cell. Hypericin inhibited electron transfer and consequently oxygen production by PSII particles. For half maximum inhibition of oxygen evolution, with PSII membrane particles, the molar ratio of chlorophyll/hypericin was about 10:1.
Hydrophobicity Scale of Amino Acids as Determined by Absorption Millimeter Spectroscopy: Correlation with Heat Capacities of Aqueous Solutions
Authors: Vorob’ev Mikhail M.
Published: August 2018

Hydration indexes of protein α-amino acids were measured by the new method of absorption millimeter spectroscopy (AMS) at 10 mm wavelength (1.05 cm-1; 31.42 GHz). This region of electromagnetic waves, located between the region of high-frequency dielectric spectroscopy and that of far-infrared spectroscopy, allows to measure hydration on the basis of different rotational and reorientational mobilities of water in hydration shell. Contribution to hydration of the methylene group is shown to be significantly greater than that of polar -OH , -CONH2 and -COOH groups, while the contribution of the charged -CH(N+H3)COO- group is even negative. The high sensitivity of AMS method to hydrophobic hydration allows to build up the hydrophobicity scale which gives an acceptable correlation (r=0.95) with the heat capacities of the aqueous solutions of amino acids. Thus, millimeter absorption spectroscopy, the method of hydration determination at a molecular level (determination of V-structure of water with lifetime ~50 ps), allows to quantitatively distinguish hydration of polar and non-polar groups as well as calorimetry does at a macroscopic level.
Differential Responses of Potato Cell Suspensions to a Culture Filtrate of Phytophthora infestans
Authors: Awan M. F. M. , Maciejewska U. , Kleczkowski K. , Wielgat B.
Published: August 2018

General (polygenic) resistance of plant hosts to an attack by a range of pathogens is an important feature of plant defense responses against the infection. In search of biochemical markers defining this resistance, cell suspensions derived from leaves of potato (Solanum tuberosum L .) cvs. Tarpan and Bzura that are polygenically susceptible and resistant to Phytophthora infestans, respectively, were inoculated with culture filtrate (CF) of the fungus. Cell suspension of Tarpan responded to CF treatment by a higher extracellular alkalinization and more significant reduction in their viability and growth than those of the Bzura cultivar. The stimulation of phenylalanine ammonia-lyase (PAL ) activity but not of β-1,3-glucanase, was significantly higher in CF treated Bzura cells than in Tarpan ones. The obtained results suggest that sensitivity to the fungal toxins and variation of PAL activity may represent useful markers for the evaluation of polygenic resistance in potato.
Induction of Single-and Double-Strand Breaks in Plasmid DNA by Monoenergetic Alpha-Particles with Energies below the Bragg-Maximum
Authors: Scholz Volker , Weidner Jürgen , Köhnlein Wolfgang , Frekers Dieter , Wörtche Heinrich Johannes
Published: August 2018

The yield of single-strand breaks (ssb) and double-strand breaks (dsb) produced by alpha-particles at the end of their track in DNA-films was determined experimentally. Helium nuclei were accelerated to 600 keV in the 400 kV ion accelerator and scattered at a carbon target. The elastically scattered alpha-particles with energies of 344 keV and 485 keV were used to irradiate supercircular plasmid DNA in vacuo.

For the dosimetry of the alpha-particles a surface barrier detector was used and the energy distribution of the alpha-particles determined. The energy loss of the particles in the DNA-layer was calculated. DNA samples were separated into the three conformational isomers using agarose gel electrophoresis. After fluorochromation the number of ssb and dsb per plasmid DNA molecule was established from the band intensities assuming the validity of Poisson statistics.

Linear dose effect correlations were found for ssb and dsb per plasmid molecule. In the case of 344 keV-alpha-particles the yield of dsb was (8.6 ± 0 .9)× 10−11 breaks/Gy × dalton. The ratio of ssb/dsb was 0.5 ± 0.2. This is at least a factor of six larger than the ratio found in experiments with higher energy alpha-particles and from model calculations. Similar experiments with protons yielded a relative biological effectiveness (rbe) value of 2.8 for the induction of double-strand breaks by track end alpha-particles.
Effect of Cisplatin Alone and in Combination with γ-Radiation on the Initiation of DNA Synthesis in Friend Leukemia Cells
Authors: Ganeva Roumiana L. , Tzvetkov Lyuben M.
Published: August 2018

The effect of the anticancer drug cisplatin (alone and in combination with γ-radiation) on the initiation of DNA synthesis in Friend leukemia cells was studied. A method for isolation of DNA fractions containing the origins of replication was used. It was found that cisplatin decreased the rate of the initiation of DNA synthesis. The mild γ-radiation has previously been observed to inhibit the initiation of DNA synthesis. In the present investigation the combination of cisplatin and γ-radiation showed additive effects without synergism on the initiation of DNA biosynthesis.
Absolute Configuration of the Isopyoverdin Chromophore
Authors: Michalke R. , Taraz K. , Budzikiewicz H. , Thonart Ph. , Jacques Ph.
Published: August 2018

By ozonolytic degradation of the chromophore of isopyoverdin from Pseudomonas putida BTP 1 ʟ-2,4-diaminobutyric acid was obtained. This proves that the C-3 of the chromophore is S-configurated.
Herbicide Resistance and Growth of D1 Ala251 Mutants in Chlamydomonas
Authors: Förster Britta , Heifetz Peter B. , Lardans Anita , Boynton John E. , Gillham Nicholas W.
Published: August 2018

We elucidated the effects of substituting seven amino acids for Ala at residue 251 of the Chlamydomonas reinhardtii D1 protein on herbicide resistance and photoautotrophic growth. Ala251 has been suggested to play a key role in the structural integrity and function of the stromal loop between transmembrane helices IV and V of D1 and has previously been shown to affect resistance to “classical” PSII specific herbicides. Sensitive and rapid microtiter assays were employed to compare herbicide resistance and photoautotrophic growth in the various mutants. Substitution of Ala251 by Ile, Leu or Val conferred resistance to the PSII herbicides atrazine, bromacil and metribuzin but not to DCMU, and impaired photoautotrophic growth in high and low light. Compared to an otherwise isogenic wildtype strain, the lie and Val mutants exhibited nearly identical levels of herbicide resistance and reduced growth while the Leu mutant had even slower growth and higher levels of herbicide resistance. In contrast Cys, Pro, Ser and Gly mutants were phenotypically indistinguishable from wildtype in terms of herbicide sensitivity and photoautotrophic doubling times. Collectively the seven Ala251 mutations differed markedly from an Ala mutant (dr-1) at the well characterized Ser264 D1 residue in terms of herbicide resistance and photoautotrophic growth
The Activity of Thymidine Phosphorylase Obtained from Human Uterine Leiomyomas and Studied in the Presence of Pyrimidine Derivatives
Authors: Miszczak-Zaborska Elżbieta , Woźniak Krystyna
Published: August 2018

Partially purified samples of thymidine phosphorylase were obtained from four preparations of human uterine leiomyomas and uteri using the method of Yoshimura et al. (1990), Biochim. Biophys. Acta 1034, 107-113. Among the studied twelve pyrimidine derivatives, 5- bromouracil. 5-nitrouracil, 5-fluorouracil, 6-aminouracil, 4,6-dihydroxy-5-nitropyrimidine are competitive inhibitors, while allyloxymethylthymine is an uncompetitive inhibitor of thymidine phosphorylase activity. 6-benzyl-2-thiouracil inhibits the activity of the enzyme in a mixed way. The most potent inhibitor of the thymidine phosphorylase activity is 5-bromouracil and uracil the weakest one. Stronger inhibition of these compounds on the activity of thymidine phosphorylase was found in uterine leiomyomas than in uteri
Comparative Effects of Scopoletin and Aflatoxin Bj on Bovine Hepatic Mitochondrial Respiration in vitro
Authors: Obasi S. C. , Obidoa O.
Published: August 2018

A comparative study of the in vitro effects of the coumarin compounds, scopoletin and aflatoxin B1 (AFB1), on bovine (Bos indicus) hepatic mitochondrial respiration was carried out polarographically, using isocitrate -NAD+ (3 - site), succinate (2- site), and reduced cytochrome c (1 - site), as respiratory substrates. Both scopoletin and AFB1 elicited a substrate - dependent stimulation or inhibition of the mitochondrial states 4 and 3 respiration. The results suggest that AFB1 has a higher tendency to inhibit the mitochondrial respiration than scopoletin. while scopoletin showed higher uncoupling effects than AFB1. The effects of scopoletin and AFB1 on mitochondria were more pronounced on the electron transport than on phosphorylation reaction. The extent (3-35% ) of AFB1 induced inhibition of bovine mitochondrial respiration observed in this study, was appreciably lower than the values indicated in other animal species (rats and guinea fowls) reported in previous studies using equivalent concentrations of the toxin. These results were discussed in terms of the susceptibility of the animal species to the toxic effects of scopoletin and AFB1
The Rieske Protein from Purple Sulfur Bacteria Is an Extrinsic Protein
Authors: Szczepaniak Andrzej , Uhrig Joachim , Gubernator Beata
Published: August 2018

The mode of membrane attachment of the Rieske iron-sulfur protein from cytochrome be, complex of Rhodospirillum rubrum has been studied using biochemical approaches.

In contrast to cytochrome c1 the bacterial Rieske protein was extracted from chromatophores using chaotropic agents (NaSCN, urea, guanidine), an alkaline pH and relatively low concentration of Triton X-100.

The results presented here lead to the conclusion, that the Rieske protein from chromatophores is extrinsic and that their association with the rest of the complex involves hydropho­bic interactions.
Inhibitory Effects of Synthetic Lanthanum-Crown Ether at the Reducing Side of Photosystem II
Authors: Sabat Surendra Chandra , Padhye Subash , Mohanty Prasanna
Published: August 2018

Inhibitory effects of lanthanum-crown [La-(Pic)3 (15-crown-6) 3H2O].was investigated on the O2 evolution activity of photsystem II particles. Lanthanum (La)-crown inhibited the electron flow at the reducing side of PS II complex. Short duration (1-2 min) treatment of PS II membranes with trypsin partly developed resistance to La-crown inhibition. However, longer proteolytic treatment (>2 min) appeared to expose newer site(s) for La-crown inhibi­tion. The inhibitory constant (Ki) for La-crown was nearly 0.17 | μᴍ . This inhibitory capacity is about 4 to 5 times less than the potent PS II inhibitor diuron which also binds at the acceptor side of PS II. The number of binding sites for La-crown was found to be 1 per 20 chlorophyll molecules. The Hill plot analysis showed the presence of three distinct straight lines suggesting that the compound acts at least at three sites. Furthermore, from the slope value (Hill coefficient) it is suggested that two of these sites provide minimum of two binding domains for the inhibitor.
A New Inhibitor of Synovial Phospholipase A2 from Fermentations of Penicillium Sp. 62-92
Authors: Witter Ludwig , Anke Timm , Sterner Olov
Published: August 2018

Penidiamide, a new tripetide containing dehydrotryptamine, glycine and anthranilic acid linked together by two amide bonds, and oxindole were isolated from submerged cultures of Penicillium sp. 62-92 . Both compounds preferentially inhibited human synovial phospholipase A2, penidiamide with an IC50 of 30 μᴍ and oxindole of 380 μᴍ. With the exception of U 937 cells (leukemia, human), no cytotoxic activities were detected against HL-60- (leukemia, human), HeLa S3- (epitheloid carcinoma, human), BHK 21- (kidney fibroblasts, hamster), and L1210-cells (leukemia, mouse). No antimicrobial activity was detected for oxindole, and only weak antibacterial activity for penidiamide. The structure of penidiamide was elucidated by spectroscopic methods.
Structure/Odor-Relationships of Longifolene Derived Esters December 30, 1997
Authors: Spreitzer Helmut , Pichler Andrea , Piringer Iris , Wolf Rainer
Published: August 2018

A series of epimeric esters of longicamphenilol and longifolol are prepared and their odorous properties described. It is shown that there are significant differences between the exo- and endo-series. All esters are well accessable starting from longifolene.
Five New Bioactive Sesquiterpenes from the Fungus Radulomyces confluens (Fr.) Christ
Authors: Fabian Kerstin , Lorenzen Kirsten , Anke Timm , Johansson Martin , Sterner Olov
Published: August 2018

The three protoilludanes radulone A (1), radulone B (2) and radudiol (3), the illudalane radulactone (4) and the illudane radulol (5) were isolated from the extracts of the culture fluids of the basidiomycete Radulomyces confluens. The structures of the five new compounds were determined by spectroscopic techniques. Radulone A (1) is a potent inhibitor of human and bovine platelet aggregation stimulated by different agonists, inhibiting preferentially the aggregation of human platelets induced by ADP with an IC50 value of 2 μᴍ . In addition 1 exhibits cytotoxic and antimicrobial activities. The other four compounds exhibited weak antimicrobial and cytotoxic activity.
Influence of Chemical Treatments on Glutathione S-Transferases of Maize with Activity Towards Metolachlor and Cinnamic Acid
Authors: Cottingham Charles K. , Hatzios Kriton K. , Meredith Sue
Published: August 2018

The subcellular distribution of glutathione S-transferase (GST) activity extracted from

shoots of 3-day-old etiolated seedlings of maize (Zea mays L., Northrup-K ing 9283 hybrid)

and the induction of soluble and m em brane-bound G ST activity by the safener benoxacor,

the herbicide metolachlor and their com bination (CGA -180937) were investigated. GST activity

extracted from maize shoots was detected in both cytosolic and microsomal fractions

and utilized l-chloro-2,4-dinitrobenzene (CDNB ), metolachlor, and trans-cinnamic acid (CA)

as substrates. Soluble GST activity extracted from maize shoots was greater than m icrosom al

with CDNB or metolachlor as substrate. Membrane-bound GT activity was greater than

soluble with cinnamic acid as substrate. W ashing the microsomal preparations from maize

shoots with Triton X-100 increased GST (C A ) activity. Pretreatment with the safener benoxacor

or a form ulated combination of the herbicide metolachlor with benoxacor induced soluble

GST(CDNB ), GST(metolachlor) and GST (C A ) activities in m aize shoots. Benoxacor

and CGA-180937 induced also membrane-bound GST (CDNB ) and GST(CA ) activities in

maize shoots, but did not affect membrane-bound GST (metolachlor) activity. These results

confirm that maize contains multiple GST isozymes that differ in their subsrate specificity

and inducibility by safeners or other chemicals.
Inhibition of the Non-Mevalonate 1-Deoxy-ᴅ-xylulose-5-phosphate Pathway of Plant Isoprenoid Biosynthesis by Fosmidomycin
Authors: Zeidler Johannes , Schwender Jörg , Müller Christian , Wiesner Jochen , Weidemeyer Claus , Beck Ewald , Jomaa Hassan , Lichtenthaler Hartmut K.
Published: August 2018

Various bacterial and plastidic plant terpenoids are synthesized via the non-mevalonate1-deoxy-ᴅ-xylulose-5-phosphate (DOXP) pathway. The antibiotic and herbicidal compound fosmidomycin is known to inhibit growth of several bacteria and plants, but so far its mode of action was unknown. Here we present data which demonstrate that the DOXP pathway of isoprenoid biosynthesis is efficiently blocked by fosmidomycin. The results point to the DOXP reductoisom erase as the probable target enzyme of fosmidomycin.
A New Benzo-γ-pyran Derivative Isolated from Propolis
Authors: Matsuno Tetsuya , Saito Masahiro , Matsumoto Yasuyuki , Morikawa Junji
Published: August 2018

The methanol extract of Brazilian propolis was fractionated by HPLC, based on human hepatocellular carcinoma (HuH 13) cell cytotoxicity assay. A new benzo-y-pyran derivative (PM-3) with a molecular formula of C19H22O3 (MW: 298.38) was isolated. The structure of this colorless compound was determined as 3-[2-dimethyl-8-(3-methyl-2-butenyl) benzopy-ran]-6 -propenoic acid. This compound was chemically synthesized by cyclisation of artepillin C (3-[4-hydroxy-3,5-bis (3-methyl-2-butenyl) phenyl]-2-propenoic acid).
Two Simple Methods for Measuring Isoprene Emission of Leaves by UV-Spectroscopy and GC-MS
Authors: Zeidler Johannes G. , Lichtenthaler Hartmut K.
Published: August 2018

Two new headspace methods for the analysis of iso­prene emission from detached plant leaves are described. The first method is based on the UV-absorption of isoprene emitted by leaves inside quartz cuvettes and can be used for the quantitative spectrophotometric determination of isoprene production. The second tech­nique is a micro-extraction method of isoprene from the cuvette air for GC analysis, and is very suitable for the determination of isotope-labeled isoprene by GC-MS.
ʟ-Phenylalanine Effect on Rat Brain Acetylcholinesterase and Na+,K+-ATPase
Authors: Tsakiris Stylianos , Kouniniotou-Krontiri Panagiota , Schulpis Kleopatra H. , Stavridis John C.
Published: August 2018

The effect of different L-phenylalanine (Phe) concentrations (0 .1-12.1 mᴍ) , on acetylcholinesterase (AChE ) and Na+,K+-ATPase activities of brain homogenate and pure enzymes, was investigated at 37 °C. AChE and Na+,K+-ATPase activities were determined according to Ellman G. L., Courtney D., Andres V. and Featherstone R. M. (1961), Biochem. Pharmacol. 7, 88 - 95 and Bowler K. and Tirri R. (1974), J. Neurochem. 23, 611-613 ) respectively, after preincubation with Phe. AChE activity in brain homogenate or in pure eel E.electricus enzyme showed a decrease, which reached up to 18% with concentrations of 0.9-12.1 mᴍ. Brain homogenate Na+,K+-ATPase activity showed an increase 16-65% with 0.24-0.9 mᴍ of Phe, while an activity increase of 60 -65% appeared with 0.9-12.1 mᴍ of Phe. Pure enzyme activity (from porcine cerebral cortex) was not affected by high Phe concentrations, while it was increased by low concentrations. The above results suggest: a) A direct effect of Phe on AChE, b) A direct effect of low Phe concentrations and an indirect effect of high ones on Na+,K+-ATPase.
Age-Class Differences in Lipids from the Paracloacal Glands of the American Alligator (Alligator mississippiensis)
Authors: Ibrahim Sayed A. , Avery James W. , Weldon Paul J. , Wheeler James W.
Published: August 2018

The paracloacal gland secretions of immature and adult American alligators (Alligator mississippiensis) from Louisiana were analyzed by gas chromatography/mass spectrometry and nuclear magnetic resonance spectroscopy to investigate age-class differences in lipid composition. The secretions of both immature and adult alligators contain saturated C14 and C16 free fatty acids and decyl, undecyl, dodecyl, tetradecyl, and hexadecyl acetates. Com­pounds observed only in immature alligators include dodecanoic acid, C12 and C14 alcohols, C10-C14 butanoates, an array of C8-C18 3-methylbutanoates, C12- C15 hexanoates, C12 and C14 octanoates, a C12 decanoate, C10-C14 dodecanoates, C10- C16 tetradecanoates, C12 and C14 hexadecanoates, a C12 octadecanoate, and a diterpene hydrocarbon identified as (E ,E )- 7,11,15-trimethyl-3-methylenehexadeca-1,6,10,14-tetraene (β-springene). Compounds observed only in adults include several C7-C16 free fatty acids and certain C10- C18 acetates. The age-class differences we observe in the paracloacal gland lipids of alligators from Louisiana are similar to those previously reported for alligators from Texas.
Radical Functions in vivo: A Critical Review of Current Concepts and Hypotheses
Authors: Saran Manfred , Michel Christa , Bors Wolf
Published: August 2018

Most of the basic knowledge about radical reactions comes from radiation chemical studies in vitro. In view of the rapidly increasing knowledge on radical reaction in vivo, it is important to reconcile the fundamental physico-chemical reaction characteristics of radicals with the need to explain their alleged biological effects. Severe problems in the understanding of their in vivo action remain unsolved. An example is phagocytosis, which seems to be a paradigm of a ‘deleterious’ radical process. The exact mechanism is not clear; so it is an open question whether the intruder is eventually killed by radicals (like OH) or by endproducts of radical reactions (like H2O2 and/or HOCl). It is even more difficult to understand signalling by radicals: owing to their chemical nature they are ‘unspecifically’ reacting species -they with­ draw or add electrons-and thus their reactions are governed by redox-properties. Since all radicals have different redox characteristics and different molecular shapes, the usual key-and-keyhole picture for molecular interaction does not apply, as there, is no reactive site conceivable which has the property of reacting with radicals ‘specifically. Our intent in this article is: (i) to briefly review some fundamental characteristics of in vitro radical reactions, (ii) to extrapolate from this to the conditions in vivo, and (iii) to discuss current hypotheses concerning the redox-regulation of cellular signalling. This leads us to the tentative conclusion that radicals per se must be tolerated by the cell and do not threaten its life, if they stay below a certain concentration limit. The main biologi­ cal implication of radical-reactions seems to be that the cell derives signals from the balance of oxidative versus reductive processes and that radicals may interact with pathways of intra-and intercellular communication.
Protection against Peroxynitrite by Selenoproteins
Authors: Sies Helmut , Klotz Lars-Oliver , Sharov Victor S. , Assmann Annika , Briviba Karlis
Published: August 2018

Cellular defense against excessive peroxynitrite generation is required to protect against DNA strand-breaks and mutations and against interference with protein tyrosine-based sig­ naling and other protein functions due to formation of 3-nitrotyrosine. We recently demon­ strated a role of selenium-containing enzymes catalyzing peroxynitrite reduction. Glutathione peroxidase (GPx) protected against the oxidation of dihydrorhodamine 123 (D H R) by perox­ ynitrite more effectively than ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one), a selenoor-ganic compound exhibiting a high second-order rate constant for the reaction with peroxynit­ rite, 2 × 106 M-1 S-1. The maintenance of protection by GPx against peroxynitrite requires GSH as reductant. Similarly, selenomethionine but not selenomethionine oxide exhibited inhibition of rhodamine 123 formation from DHR caused by peroxynitrite. In steady-state experiments, in which peroxynitrite was infused to maintain a 0.2 μᴍ con­ centration, GPx in the presence of GSH, but neither GPx nor GSH alone, effectively inhib­ ited the hydroxylation of benzoate by peroxynitrite. Under these steady-state conditions peroxynitrite did not cause loss of ‘classical’ GPx activity. GPx, like selenomethionine, pro­ tected against protein 3-nitrotyrosine formation in human fibroblast lysates, shown in West­ern blots. The formation of nitrite rather than nitrate from peroxynitrite was enhanced by GPx , ebselen or selenomethionine. The selenoxides can be effectively reduced by glutathione, establishing a biological line of defense against peroxynitrite. The novel function of GPx as a peroxynitrite reductase may extend to other selenoproteins containing selenocysteine or selenomethionine. Recent work on organotellurium compounds revealed peroxynitrite reductase activity as well. Inhibition of dihydrorhodamine 123 oxidation correlated well with the GPx-like activity of a variety of diaryl tellurides.
Evaluation of the Antioxidant Capacity of Ubiquinol and Dihydrolipoic Acid
Authors: Nohl H. , Gille L.
Published: August 2018

Ubiquinone and α-lipoic acid are natural constitutents which are involved in mitochondrial energy metabolism. Their bioenergetic activities require redox-cycling. In the case of a-lipoic acid redox-cycling leads to dihydrolipoic acid which occurs in multienzyme com plexes in­ volved in the citric acid cycle while UQ recycles through semi-and divalently reduced ubiqui­ nones in the respiratory chain. We have proved the validity of the concept about the antioxi­ dant function of these natural compounds in their reduced form. Ubiquinol was found to interfere with lipid peroxidation of liposomal membranes being itself degradated by two consecutive oxidation steps. Dihydrolipoic acid was found to totally recycle ubiquinone to the antioxidant active divalently reduced form. In contrast to the antioxidative derived reaction products of ubiquinols which in turn promoted lipid peroxidation, the antioxidant derived reaction product of dihydrolipoic acid was the unreactive two electron oxidation product a-lipoic acid. Our experim ents demonstrate the existence of an dihydrolipoic acid driven recycl­ ing of UQ to the antioxidative-active UQH2. The efficiency of the antioxidative capacity of the latter was found to be diminished through prooxidant activities of the antioxidant-derived metabolites.
Sulfite Induces Release of Lipid Mediators by Alveolar Macrophages
Authors: Beck-Speier Ingrid , Dayal Niru , Denzlingerb Claudio , Haberl Christopher , Maier Konrad L.
Published: August 2018

Air pollutants are supposed to modulate physiological responses of alveolar macrophages (AM ). This study was addressed to the question whether at neutral pH sulfur(IV) species in comparison to sulfur(VI) species cause AM to release proinflammatory mediators and which pathways are involved in their generation. Supernatants obtained from canine AM treated with sulfite (0.1 mᴍ to 2 mᴍ) enhanced the respiratory burst of canine neutrophils, measured by lucigenin-dependent chemiluminescence, whereas supernatants derived from AM treated with sulfate (1 mᴍ) did not. The neutrophil-stimulating activity released by sulfite-treated AM consisted of platelet-activating factor (PAF) and leukotriene B4 (LTB4) as shown by desensitization of the corresponding receptors. Inhibitors of phospholipase A2 substantially suppressed release of neutrophil-stimulating activity by sulfite-treated AM. Inhibition of 5- lipoxygenase in sulfite-treated AM also reduced neutrophil-stimulating activity, while inhibition of cyclooxygenase had no effect. In conclusion, sulfite induces AM to release lipid mediators via phospholipase A2- and 5-lipoxygenase-dependent pathways. These mediators activate neutrophils via the receptors for PAF and LTB4.
Terpenoids and Phenylethyl Esters from the Exudate of the Australian Plant Ozothamnus ledifolius (Asteraceae)
Authors: Arriaga-Giner Fco. Javier , Rumbero Angel , Wollenweber Eckhard
Published: August 2018

The leaf exudate of Ozothamnus ledifolius, previously reported to contain a series of flavonoid aglycones, mostly consists of a mixture of terpenoids. From this resinous material we now identified four sesquiterpenes, a diterpenediol and two pentacyclic triterpene acids. In the phenolic portion we found three phenylethyl esters.
Isolation and Kinetic Analyses of the Soluble F1 ATPases from Mitochondria of Wheat and Pearlmillet
Authors: Sane Aniruddha P. , Sane Vidhu A.
Published: August 2018

The mitochondrial F1 ATPases from two cereal crops, wheat and pearlmillet, were purified and studied. The wheat F1 ATPase could be purified to homogeneity and is apparently com­posed of six subunits with apparent molecular weights of 55 kDa (α and β), 35 kDa (γ), 26 kDa (δ’) and 22 kDa (δ). The e subunit was barely detectable. Both enzymes reveal typical non-linear kinetics but show variability in their response to bicarbonate and chloride. While the wheat F1 ATPase is stimulated by bicarbonate and chloride, the pearlmillet F1 ATPase is inhibited by both anions. The two enzymes are Mg2+ dependent ATPases and are competitively inhibited by Ca2+, unlike maize, pea and turnip ATPases. Both the enzymes also possess a GTPase activity which is two fold higher than the ATPase, unlike rice, sorghum and oat root F1 ATPases.
Influence of Some Lysosomotropic Compounds on Calcium Ion Desorption Process from Liposome Membrane
Authors: Kuczera J. , Witek S. , Kral T. E. , Hładyszowski J. , Łuczyński J. , Przestalski S.
Published: August 2018

The effect of a group of model lysosomotropic compounds on the process of Ca2+ ion desorption from lecithin liposome membranes was studied. The compounds studied were: hydrochlorides of fatty acids 2-dimethylaminoethyl esters (DM-n) for n = 9, 11, 13 and 15 carbon atoms in the fatty acid alkyl chain and methochloride of 2-dimethylaminoethyl laurate (DMS-11).

It was found that all the compounds studied caused increased desorption with increasing concentration of the compound. Most effective was the quaternary ammonium salt, DMS-11. Moreover, it was found that the process of Ca2+ desorption from the membrane depended on pH of the medium. Compound DM-11 was more active at pH 8 than at pH 5. The action of DM-n compounds depended on the alkyl chain length, DM-11 and DM-13 being the most active.

Apparently free amines penetrate the phospholipid membranes and incorporate into its hydrophobic core causing structural deformations. Hydrochlorides of fatty acids and the quaternary ammonium salt induce desorption of calcium ions mostly as a result of competitive electrostatic interactions. By quantum chemistry, PM3 method, and methods of molecular modelling we established the higher hydrophilicity of the polar head of DM-n series with respect to the polar head of the DMS-n compounds. DM-n compounds possess both acceptor and donor properties for hydrogen bonding while DMS-n are instrumental as acceptors only.

It should be noted, that the results obtained in this paper for model membranes are in accordance with those for biological ones.
Purification and Partial Characterization of Glyceraldehyde-Phosphate Dehydrogenase from Electric Organ of Electrophorus electricus (L.)
Authors: Giovanni-De-Simone S. , Hassón-Voloch A. , Batista-e-Silva C. , Nery-da-Matta A.
Published: August 2018

The glyceraldehyde-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) was purified to homogeneity from electric organ of Electrophorus electricus (L.) by a hydrophobic chroma­ tography method on deacetylcolchicine-Sepharose. The purification resulted in a 162 fold increase in specific activity of the GAPDH and final yield was approximately 37%. The purified enzyme showed a single band in SDS-PAGE, with an apparent molecular mass of 36 kDa. The purity of the colchicine-Sepharose isolated material was analysed by isoelectro-phocusing and immunoblotting using a heterologous rabbit serum anti-GAPDH. Sequence analysis of the 40-N-terminal amino acids, determined by Edman degradation, revealed its identity to other GAPDHs proteins being the largest number of identical amino acids to lobster (92.5%), rabbit muscle (85%) and human liver (80%) GAPDH.
Inhibition of Lipid Peroxidation in the Erythrocyte Membrane by Quaternary Morpholinium Salts with Antioxidant Function
Authors: Kleszczyńska H. , Oświęcimska M. , Witek S. , Przestalski S.
Published: August 2018

The antioxidant activity of five new compounds from a group of quaternary ammonium salts with antioxidant function has been investigated. The effect of the compounds on the degree of lipid oxidation in the erythrocyte membrane subjected to UV radiation was studied. It was found that all the salts used decreased oxidation of the lipids in the erythrocyte membrane. The antioxidant activity of the ammonium salts studied increased with their alkyl chain length. Three compounds with the longest alkyl chains were the most active antioxidants, and their antioxidant properties were comparable to those of a flavonoid extracted from haw­ thorn. The antioxidant effectiveness of the ten-carbon alkyl chain compound was comparable with that of the known antioxidant 3,5-di-t-butyl-4-hydroxytoluene (BHT). The least effective antioxidant studied proved to be the eight-carbon alkyl chain compound. The effect of these compounds on fluidity of the erythrocyte membrane has been studied, and for all an increase of fluidity of the membrane was observed. The changes in erythrocyte ghosts fluidity depended both on concentration and type of compound. A fluorimetric study also indicated that rigidity of the erythrocyte membrane increased with degree of its oxidation, but with antioxidants present membrane rigidity increased less.
The Course of Enzymatically Induced Lipid Peroxidation in Homogenized Porcine Kidney Tissue
Authors: Kießling Uwe , Spiteller Gerhard
Published: August 2018

Homogenization of mammalian tissue - exemplified by porcine kidney - causes enzymatically induced lipid peroxidation (LPO) processes proven by measuring the amounts of the typical lipid peroxidation products 9- and 13-hydroxy-octadecadienoic acid (HODE) either after homogenization in aqueous (activation of enzymes) or an organic (inactivated enzymes) solvent. A kinetic study revealed that the level of the 9- and 13-isomer reached maximum values 6 hours after tissue injury. Within one day the amount of these primary oxidation products was reduced fast, indicating that they undergo degradation in their biological environment. In contrast, the level of 10-hydroxy-octadecanoic acid - obviously derived from LPO of oleic acid - increased continuously even after one day. These observations reflect that the generation and degradation of hydroperoxides occurs at different rates which might be of interest in pathological processes connected with tissue injury, e.g. myocardial infarction.
The Mental Life of Artifacts. Explications, Questions, Arguments
Authors: Buschlinger Wolfgang , Vollmer Gerhard , Walter Henrik
Published: August 2018

Our working assumption reads: Every mental property exhibited by a natural system can be exhibited by an artificial system, at least in principle. Is this true? The paper is in two parts. The first part is explicative: What do we mean by ‘natural’ or by ‘artificial’? When are we ready to ascribe thinking to a system? We show that sometimes behavior is enough, sometimes underlying mechanisms are decisive. We study the difference between simulation and realization of a property and the kinds of explanation used in the philosophy of mind. The second part is argumentative. We collect and discuss positive arguments for and critical arguments against the working hypothesis. No decisive counterargument is found
Effect of Ecological Pressures on Brains: Examples from Avian Neuroethology and General Meanings
Authors: Wagner Hermann , Luksch Harald
Published: August 2018

Comparative neuroethological research emphasizes that brains of animals have been shaped by the specific demands and constraints imposed by the ecological niche that a species occupies. Since avian species have developed very diverse life styles and occupy extreme ecological niches, bird brains should show many specializations, which may be revealed in species that have survived under high ecological pressures. In this paper, we will give several examples of adaptations, in which we are able to correlate structural and physiological spe­cializations to the specific ecological demands: adaptations found to nocturnal hunting in barn owls, the characteristics of bird song and its underlying neurobiological correlates, retinopetal projections and their relation to peripheral attentional switching, looming detection, and adaptations related to memory capacities of food-storing birds. We stress especially that the analysis of the animal’s ecological situation is important in understanding the factors that shaped both behavior and the neuronal substrate.