bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytochromes and Anaerobic Sulfide Oxidation in the Purple Sulfur Bacterium Chromatium warmingii
Authors: Wermter Ursula , Fischer Ulrich
Published: August 2018

Two soluble acidic c-type cytochromes - c' and c-552 - were isolated by ion exchange :hromatography, gel filtration and ammonium sulfate fractionation. Cytochrome c' is a high-spir tochrome with maxima at 399 nm. 490 nm. and 634 nm in the oxidized form and at 550 nm. 15 nm and a characteristic shoulder at 434 nm in the reduced state. The best purity index obtained A280/A399) was 0.35. Cytochrome c' is autoxidizable, has a molecular weight of 12 000 (estimate by sodium dodecylsulfate electrophoresis), a midpoint redoxpotential of + 10 mV and an iso­electric point at pH 4.0. The reduced cytochrome c' reacts with carbon monoxide. The reaction reversible. Cytochrome c-552 shows maxima at 552 nm, 523 nm and 417 nm in the reduced for ind at 408 nm in the oxidized state. The best purity index obtained (A280/A408) was 0.94. "ytochrome c-552 has a molecular weight of 30 000 and an isoelectric point between pH 4.1 Zhromatium warmingii also contains a membrane-bound cytochrome c-552. During anaerobic sulfide oxidation, elemental sulfur and sulfate were formed at the same time. When all sulfide consumed by the cells, the remaining intracellular elemental sulfur was further oxidized to sulfate
Distribution of Chlorophylls, Carotenoids and Quinones in Chloroplasts of Higher Plants
Authors: Grumbach K. H.
Published: August 2018

Leaves, cotyledons, isolated chloroplasts and subplastid fractions (thylakoids and envelopes) of radish (Raphanus sativus L. cv. Saxa) and spinach (Spinacia oleracea L. cv. M atador) were assayed for their pigment and quinone content and com position. Virtually all the chlorophylls, carotenoids and quinones were contained in the thylakoids. Envelopes prepared by the method described contained very low amounts o f chlorophyll a and b, violaxanthin and neoxanthin, but no β-carotene, lutein, zeaxanthin and antheraxanthin. Among the quinones trace amounts of plastoquinone and a-tocopherol but no plastohydroquinone, a-tocoquinone and phylloquinone were detected. Presented data may be taken as evidence that in vivo the chloroplast envelope is not a location site of carotenoids and quinones as generally accepted. Possible im plications for the biosyntheses of quinones and pigments are discussed
Rate of OH Radical Induced Strand Break Formation in Single Stranded DNA under Anoxic Conditions. An Investigation in Aqueous Solutions Using Conductivity Methods
Authors: Bothe Eberhard , Qureshi G. Ali , Schulte-Frohlinde Dietrich
Published: August 2018

Single stranded DNA (ssDNA) in aqueous N2O-saturated solution was pulse-irradiated with electrons or irradiated under steady-state conditions with 60Co-y rays. The conductivity increase after irradiation was measured as a function of concentration. pH, temperature, metal cation content and additives. The conductivity increase could be shown to be due to the release of associated counterions (Na+ or H+) as a result of the formation of chain breaks. At 28 mg 1 1 DNA ~ 8 sodium ions are liberated per 100 eV absorbed energy (G(Na+)= 8.3). On the basis of G value for single-strand breaks (ssb) of G(ssb) = 0.55, it is calculated that 8.3/0.55 = 15 sodium ions per strand break are set free. The release of Na+ monitored by 23Na-NMR at pH 7 as a function of dose corresponds to that of the conductivity increase. The rate of the conductivity increase does not depend on dose/pulse (range 2-20 J kg-1) and shows at least two components. The rate constant of the fast and dominant component is constant above pH 8.5 (A: = 38 s_ 1, 20 °C) and increases linearly with proton concentration below pH 7. Values of 13kcal/mol for the activation energy and 5x 10" s_l for the frequency factor were obtained at pH 7.3. Addition of /7-benzoquinone (pBQ) increases the rate constant of the fast component proportionally to the concentration of pBQ. From these results the rate-determining step of the fast conductivity increase is concluded to be the splitting of DNA radicals. The pH dependence and the magnitude of the activation energy agree with results from low molecular weight model compounds for the C-4' mechanism; this mechanism involves a heterolytic splitting of the phosphoric acid ester bond starting from the 4' radical of DNA
Identification o f the Major Anthocyanin o f Carrot Cells in Tissue Culture as Cyanidin 3-(Sinapoylxylosylglucosylgalactoside)
Authors: Harborne Jeffrey B. , Mayer Alfred M. , Bar-Nun Nurit
Published: August 2018

In contrast to earlier reports, the major anthocyanin of carrot cells grown in tissue culture has been identified as cyanidin 3-(sinapoylxylosylglucosylgalactoside). It is thus the same as one of the major acylated pigments in the leaf and flower of the whole plant. Daucus carota is therefore not anomalous among higher plants in its anthocyaninsynthesising capacity in callus or shake culture
Sequence analysis of the cloned cucumis melo highly repetitive satellite dna
Authors: Brennicke A. , Hemleben V.
Published: August 2018

The primary sequence of the prom inent Cucumis melo satellite DNA is presented. The cloned Hind III-repeat unit has a length of 352 bp and a GC-content of 56%. Within this sequence an inverted repeat of 9 bp, including a 286 bp loop, and one direct repeat are shown. Several open reading frames are possible following the sequence in both directions whose significance is not yet clear. The sequence has been compared with other highly repetitive DNA sequences of Sinapis alba and Scilla sibirica. The genomic satellite DNA exhibits an unusual behaviour in actinomycin D-CsCl gradients in comparison to ribosomal D NA
Neue Untersuchung über Inhaltsstoffe der Kreuzdornrinde, IV [1] Die Hauptanthraglykoside der Rinde von Rhamnus catharticus L.: Emodin-8-O-β-gentiobiosid, -glukosid und -primverosid / A New Investigation on the Com position of Rhamni cathartici Cortex, IV [1] The Main Anthraglycosides of the Stem Bark of Rhamnus catharticus L.: Emodin-8-0-/β-gentiobioside, -glucoside and -primveroside
Authors: Rauwald Hans-W.
Published: August 2018

From the stem bark of Rhamnus catharticus L. (purging buckthorn) the three main anthraquinone glycosides have been isolated by the new method of droplet-countercurrent-chromatography. Their structures were spectroscopically identified as em odin-8-O-β-gentiobioside, -glucoside and -primveroside. From these the primveroside is a new substance, the gentiobioside has been found for the second time in plant material. The structures were confirmed by 13C NMR spectroscopy for the first time in O-glycosides of emodin type. Especially the differences in 13C chemical shifts of the free resp. acetylated aglycones and glycosides are useful parameters for determining the position of O-glycosylation in the 1,8-dihydroxy-anthraquinone derivatives
Fungitoxic Isoflavones from Lupinus albus and other Lupinus Species
Authors: Ingham John L. , Tahara Satoshi , Harborne Jeffrey B.
Published: August 2018

The constitutive isoflavones genistein, 2'-hydroxygenistein, wighteone and luteone have been isolated in varying amounts from methanolic leaf washings of eight species belonging to the legume genus Lupinus. These four compounds likewise occur in the flower buds, stems, roots and immature pods of L. albus, and in stems and roots of L. angustifolius and L. mutabilis. A minor isoflavone present in L. albus and L. luteus leaf washings has been identified by chemical and spectroscopic procedures as 5,7,4'-trihydroxy-3-methoxy-6-(3,3-dimethylallyl)isoflavone (lupisoflavone). Apart from genistein, 2'-hydroxygenistein, wighteone and luteone, the roots of L. albus also contain alpinumisoflavone, licoisoflavone B and 6,3'-di-(3,3-dimethylallyl)genistein (lupalbigenin)
Affinity of Phycocyanin Chromopeptides to Histidyl-Sepharose Gels: A Model for Histidine-Tetrapyrrol-Interactions in Biliproteins
Authors: Rabier Jaques , Vijayalakshmi Mookambeswaran , Rüdiger Wolfhart
Published: August 2018

C-Phycocyanin from the cyanobacterium Spirulina m axim a was digested with pepsin to yield chromopeptides and colorless peptides. This mixture was applied to columns of histidyl-Sepharoseunder a variety of conditions (pH-value, ionic strength of buffer). We found a good separation of several chromopeptides from each other and from colorless peptides due to differential interaction of phycocyanobilin chromophore with the histidyl residue of the gel. The separation is suppressed by the use of imidazole buffer. Control experiments were perform ed with purified chromopeptides and with octyl-Sepharose and DEAE-Sepharose. The nature of interaction which probably involves charge transfer interaction besides hydrophobic and ionic forces is discussed with regard to the significance for phytochrome
Ribulose-1,5-bisphosphate Carboxylase-Oxygenase: New Aspects Respective the pH-Dependance of the Carboxylation Reaction
Authors: Braun P. , Bode J. , Wild A.
Published: August 2018

The investigation was directed towards the effects of reaction conditions, substrates and pH on the carboxylation reaction of ribulose-1 ,5-bisphosphate carboxylase-oxygenase in the crude enzyme extracts from several plants. Optimal substrate concentrations (HCO3
- and RubP) were determined. The highest carboxylase activity was attained with Tris/HCl buffer. The pH activity profile was quite sharp with an optimum at pH 7.8. Purified and crystallized carboxylase yielded a broad optimum curve under the same reaction conditions
The 'Double' Michaelis-Menten Equation: Estimation of Parameters
Authors: Borstlap Adrianus C. , Doucet Paul G.
Published: August 2018

When the concentration dependence of an enzymic reaction or a transport process can be described by the sum of two Michaelis-Menten terms, reliable data that relate reaction rate and substrate concentration can be obtained even when as much as 70 per cent of substrate was consumed during the assay. Each data pair consists of the average reaction rate during an assay and the concentration where the instantaneous reaction rate was equal to the average rate. Although that concentration cannot be computed exactly (as it depends on the four kinetic parameters), it may be computed in a good approximation as if the reaction followed the simple Michaelis-Menten relationship. The relative error in the approximated concentration for 1 ≦ K2/K1 ≦ 105 and 10-2 ≦ V2/V1 ≦ 102 did not exceed 5 per cent up to 50 per cent of substrate consumption, and did not exceed 10 per cent up to 70 per cent of substrate consumption
Effect of Sodium Cholate on the Phase Transition Temperature of Dipalmitoyl Phosphatidylcholine
Authors: Banerjee Srabani , Chatterjee S. N.
Published: August 2018

On treatment with sodium cholate, the phase transition temperature (Tc) of multilamellar liposomes derived from dipalmitoyl phosphatidylcholine (DPPC) progressively decreased with increasing cholate: lipid-P molar ratio. A molar ratio of 4.5 caused a one degree depression in Tc. The unilamellar cholate vesicles of DPPC exhibited the same Tc as that of the multilamellar ones. The formation of unilamellar vesicles from the multilam ellar ones by cholate treatm ent was investigated by electron microscopy
Zur Stereochemie von Silybin / The Stereochemistry of Silybin
Authors: Lotter Hermann , Wagner Hildebert
Published: August 2018

The X-ray Structure of Silybin from Silybum marianum Gaertn. was determined. The com­pound was found to be a diastereomeric mixture (1:1) in the benzodioxane part of the molecule explaining several tentative aspects about the structure known from NMR-measurements and HPLC-separations.
Identification of Anthocyanins and Intermediates of Anthocyanin Biosynthesis from Petunia hybrida Using High Performance Liquid Chromatography
Authors: Schram A. W. , Jonsson L. M. V. , Vlaming P. de
Published: August 2018

A procedure to identify dihydroflavonol (glucosides), cinnamic acids and anthocyanins in flowers of Petunia hybrida is presented. Nearly all known intermediates and anthocyanins ocur- ring in Petunia are separated on one column using different elution systems. Hydrolysis of extracts before HPLC and thin layer chromatography is in some cases necessary to make positive identification of flavonoids.

Anthocyanins in flowers of Petunia hybrida can occur, depending on genotype, as acylated anthocyanins. Two types of acylated anthocyanins have been identified differing in polarity and thus in retention times on HPLC and TLC. The difference in acylation is genetically deter­mined and gives rise to minor colour differences.
Chromopeptides from Phytochrome and Phycocyanin. NM R Studies o f the Pfr and Pr Chromophore of Phytochrome and E,Z Isomeric Chromophores of Phycocyanin
Authors: Thümmler Fritz , Rüdiger Wolfhart , Cmiel Edmund , Schneider Siegfried
Published: August 2018

Chromopeptides were prepared by pepsin digestion of C-phycocyanin isolated from the cyano­bacterium Spirulina maxima and of phytochrome isolated from seedlings of Avena sativa L. The chromopeptides were characterized by amino acid analysis. The ZZZ configurated chromophore of the phycocyanin peptide was transformed into its ZZE configurated isomer by the method of Falk et al. (Mh. Chemie 111, 159- 175, 1980) which had previously been applied to biliverdins. The 500 MHz 1HNMR spectrum of the ZZE configurated chromopeptides confirmed that its chromophore has the 15 E configuration. Irradiation yielded the ZZZ configurated isomer for which the 1H NMR spectrum was also recorded. Native phytochrome was irradiated at 660 nm to yield the maximum amount of the Pfr from (about 75% of total phytochrome). By digestion in the dark the previously described Pfr chromopeptide was obtained. The 500 MHz 1H NMR spectrum was compared with that of the ZZE phycocyanin peptide. It confirmed the 15 E con­figuration of the Pfr chromopeptide. Irradiation yielded the 15 Z configurated Pr chromopeptide. Comparison of the high resolution 1HNMR spectra of Pfr and Pr chromopeptides revealed that not only the chromophore resonances but also those of some amino acids are changed by the Pfr → Pr chromopeptide phototransformation. The results are discussed in terms of chromophore amino acid interaction.
The Influence of the Glycerol-3-Phosphate Level in the Stroma Space on Lipid Synthesis of Intact Chloroplasts
Authors: Sauer Andreas , Heise Klaus-Peter
Published: August 2018

The G3P level in chloroplasts, rapidly isolated from spinach leaves during a light-dark cycle, oscillated between 2.5 and 4 nmol · mg-1 Chi, which corresponds to a concentration of nearly 0.1 -0.2 mᴍ. In order to study the role of the stromal G3P level on chloroplast lipid biosynthesis, G3P uptake, measured by silicone oil centrifugation, has been correlated with the lipid synthesizing capacity of intact spinach chloroplasts. The level of G3P in the chloroplast stroma was decreased by high orthophosphate (Pi) concentrations in the medium. This decrease was caused by a strong Pi transport into the stroma, which is counterbalanced by a release of phosphorylated metabolites including G3P, mediated by the translocator. But because the reduced stromal G3P concentration exceeded about 3 times that for half saturation of the primary G3P acylation with oleoyl-ACP as preferred fatty acid donor, glycerolipid synthesis was not eliminated. Instead, the lowered G3P level in the stroma space limited the secondary acyla­tion step, indicated by the reduced incorporation of palmitic acid into the diglyceride fraction, and led to an accumulation of free oleic acid. Thus, beside its function as primary acyl acceptor, the stromal G3P level apparently controls the pool size of ACP bound palmitic acid by limitation of the chain elongation step from palmitoyl- to stearoyl-ACP in order to induce the specific palmitic acid channeling into the C-2-position of chloroplast lipids by the secondary G3P acylation.

A similar function may be due to fatty acid consuming reactions from outside the chloroplast like acyl-CoA thioester formation in the outer envelope membrane, stimulated by exogenous CoA and ATP. In contradiction to earlier findings intact Percoll chloroplasts showed a measurable glycerolipid labelling (3-4%) from exogenous [14C]oleoyl-CoA in the presence of G3P (0.5 mᴍ), although most of the radioactivity was found in the free fatty acid fraction (7-10%). Incorporation into diglycerides was increased two-fold under fatty acid synthesizing conditions in the medium and the resulting diglycerides were further galactosylated by UDP- galactose addition. The latter observations suggest, that even in spite of the envelope imperme­ability for physiological concentrations of long-chain acyl-CoA thioesters, fatty acid transfer from these substrates to typical chloroplast lipids cannot be totally excluded.
Characteristic Features of the Regulatory Functions of the ᴅ-Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from Spinach
Authors: Vater Joachim , Gaudszun Thomas , Lange Benita , Erdin Nazmiye , Salnikow Johann
Published: August 2018

Catalysis and regulation of CO2 fixation differ in a characteristic manner in their response to anionic modifiers and the polarity of the reaction medium. Monovalent inorganic anions inhibit catalysis and CO2-activation of the ᴅ-ribulose 1,5-bisphosphate carboxylase/oxygenase from spinach, whereas the activity and binding of NADPH and effector sugar phosphates are affected only at appreciably higher concentrations. In contrast such modulators with a dianion structure stimulate CO2 fixation by an increase of the affinity of the enzyme for the activator CO2 and stabilization of the reactive carbamate. Structure-activity studies revealed a broad specificity of the enzyme for these regulatory effects. Essentially amino groups are involved in these processes. Certain organic solvents, as methanol or acetone, stimulate CO2 fixation by a similar modification of the CO2 activation centers, as induced by dianionic effectors. These results infer that such effects are due to a decrease of the polarity at the regulatory centers of the enzyme and a concomitant change of the pK of the active lysine responsible for the binding of the activator CO2. A correlation of effector binding and activity demonstrates that already low, non-saturating concentrations of such modifiers induce high activation levels of the carboxylase and prevent the dissociation of the activated ternary complex. It is discussed that the central problem concerning the catalytical competence of ᴅ-ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) in the presence of active site directed dianionic effectors can be solved kinetically.
The Structure of a Ring-A-seco-nor-Triterpenol from Hoya australis Leaf Wax
Authors: Baas Wim J.
Published: August 2018

The main triterpenol, isolated from the alcohol fraction of very old green leaves of Hoya australis R. Br. ex Traill, has been identified as 3,4-seco-3-nor-olean-12-en-1-ol by mass spectral and NMR data.
Quercetin-3-α-ʟ-(2-O-α-ʟ-rhamnopyranosido- arabopvranosid), ein neues Flavonolglykosid aus den Samen von Brassica nigra (L.) Koch. / Quercetin-3-α-ʟ-(2-O-α-ʟ-rhamnopyranosido-arabopyranoside), a New Flavonolglycoside from Seeds of Brassica nigra (L.) Koch.
Authors: Geiger Hans , Maier Harald , Markham Ken R.
Published: August 2018

A new flavonolglycoside, quercetin-3-α-ʟ-(2-O-α-ʟ- rhamnopyranosidoarabo-pyranoside, has been isolated from seeds of Brassica nigra. Its structure is prooven by 13C-NMR.
The Possible Common Origin of tRNA and 5S rRNA
Authors: Ujhelyi Mária
Published: August 2018

Seryl tRNA (anticodon GCU) from mammalian mito­chondria shows in comparison to other mitochondrial tRNAs additional special features differing from the generalized tRNA model. When arranged in the tradi­tional cloverleaf form, eight bases fall within the TΨC loop, and the entire dihydrouridine loop is lacking. This seryl tRNA molecule is therefore shorter than other tRNAs. It was originally thought to represent a mito­chondrial analogon of 5 S rRNA and its precise classifica­tion is still disputed. The present studies suggest that this mitochondrial tRNA represents a fossil molecule which is related to the common ancestor of the present tRNA and 5 S rRNA molecules.
Rotation of Cells and Ion Exchange Beads in the MHz-Frequency Range
Authors: Küppers G. , Wendt B. , Zimmermann U.
Published: August 2018

Whereas human red blood cells and protoplasts of leaves of Avena sativa show rotation only at discrete frequencies in the kHz-range of a linear alternating electric field, rota­tion of these cells is observed at practically every fre­quency in the MHz range (15 to 200 MHz).

The cell rotation in the MHz-range can be explained in terms of field induced polarisation and orientation of per­manent dipoles within the membrane and the cell.

This interpretation is supported by the finding that Chelex beads (polystyrene cross-linked with divinylben- zene and coupled to iminodiacetic acid) do exhibit rota­tion in the MHz-range, but not in the kHz-range. It is most interesting that the Cu2+- and Ca2+-forms of the Chelex beads show a shift in the rotation frequency spectrum in addition to an increase in the magnitude of the rotation speed with respect to the Na+-form. At frequencies in the MHz-range at which rotation of the Chelex beads is not observed, formation of chains of beads from the electrodes occurs instead. This is due to positive polarisation of the beads leading to positive dielectrophoresis. The results support the view that rotation needs negative polarisability which is determined by the functional groups.
Carboxylic Acids in Wheat, Rye and Barley
Authors: Lohaus Edith , Bios Inge , Rudiger Wolfhart
Published: August 2018

Organic acids from wheat (Triticum aestivum), rye (Secale cereale), and barley (Hordeum vulgare, var. “Gerbel” and “Igri”) were analysed by gas chromatography-mass spectrometry. Two carboxylic acid fractions were obtained by chromatography on Sephadex LH 20: frac­tion A contained mainly aliphatic acids, fraction B contained mainly aromatic acids. The identified compounds (50 aliphatic and 32 aromatic acids) are listed in Tables I and II. Quanti­tative analysis was achieved by calibration of the gas chromatogram with authentic compounds or - if not available - with closely related compounds. The possibility to identify the origin of cereal food-stuff by analysis of the organic acids is discussed.
Regulation of Light Energy Distribution between Photosynthetic Pigment Systems; a Possible Role of Leaf Anatomy
Authors: Hamischfeger G. , Zenk G.
Published: August 2018

The complex anatomical structure of an intact leaf results in a distribution of photosynthetically active energy between photosynthetic pigments which is different from that observed in isolated chloroplasts. The variance is due mainly to scattering at the gas-liquid interface between cells and intercellular space which tends to increase light absorption by the long wavelength absorbing pigments through secondary fluorescence. Evidence is given in support of an active use of this feature by the higher plant to regulate energy flow at the photophysical level of light absorption.
Embryonale Hämoglobine der Säuger: Die Sequenzen der ζ-, ε-und ϑ-Ketten vom Hausschwein (Sus scrofa domestica) Embryonic Hemoglobins in Mammals: The Primary Structures of e-and 5-Chains of the Pig (Sus scrofa dom estica) / Embryonic Hemoglobins in Mammals: The Primary Structures of ζ-, ε-and ϑ-Chains of the Pig (Sms scrofa domesrica)
Authors: Bieber F. A. , Aschauer H. , Bektas S. M. , Braunitzer G.
Published: August 2018

The amino-acid sequences of all expressed hemoglobins of the pig embryo are given: Hemo­globin Gower I (ζ2/ε2), Hemoblobin Gower II (α2/ε2), Hemoglobin Heide I (ζ2/ϑ2) and Hemo­globin Heide II (α0/ϑ2). The ζ-, ε- and ϑ-chains were obtained with chromatography on CM-cellulose from isolated hemoglobin components. The primary structure was established by sequencing the tryptic peptides in the sequenator: they where isolated using HPLC. The ζ-chains from pig and human differ in 23, the ε-chains in 20 positions. The embryonic globin-gene which express the ϑ-chains, is a new one in mammals, of ε-type and up to now it could only be found in pigs: the amino-acid sequence differ in only 4 positions from the ε-chains. Because no γ-chains (fetal Hb) are expressed the sequences of all hemoglobins (5 hemoglobin chains forming 5 different hemo­globins) of ontogeny in pig are now described.
Studies on the Transport of Anions and Zwitterions of Acidic Amino Acids in Streptomyces hydrogenans
Authors: Fritsch Jürgen , Gross Werner
Published: August 2018

In Streptomyces hydrogenans, acidic amino acfds are taken up either as anions by a specific transport system or as zwitterions via a nonspecific one. Variations in the zwitterion concentration caused by changes in pH influence the uptake and exchange diffusion by the nonspecific system. Differences in pH-optima for ʟ-glutamate and ʟ-aspartate transport are due to the different pK2-­values of these amino acids. The anion transport by the specific system is accompanied by a short hyperpolarization of the membrane potential followed by a secondary influx of potassium ions into the cells.
Activation and Inhibition of Na/K-ATPase by Filipin-Cholesterol Complexation. A Correlative Biochemical and Ultrastructural Study on the Microsomal and Purified Enzyme of the Avian Salt Gland
Authors: Gassner Dieter , Komnick Hans
Published: August 2018

The Na/K-ATPase-rich microsomal fraction and purified Na/K-ATPase membranes of the salt-stressed avian salt gland were studied at defined filipin/cholesterol molar ratios (F/C) using enzyme assay and electron microscopy including negative staining, thin sectioning and freeze frac­ turing. Comparative examinations of detergent-treated microsomal fractions and the use of elec­ tron microscopic tracers revealed that F/C up to 2 activated latent Na/K-ATPase in sealed right-side-out vesicles by increasing membrane permeability without disrupting the vesicular mem­ brane. Therefore, filipin offers an alternative to the detergents for the activation of latent vectorial membrane enzymes and a possible tool to examine their subcellular localization and sidedness in the membrane. The same F/C had no stimulatory effect on the microsomal anion-ATPase sug­gesting that the 2 ATPases are not located in the same membrane.

Increasing F/C applied to the unfixed Na/K-ATPase membranes caused an increase in the number of structural F-C-complexes and a progressive lateral displacement of the enzyme par­ ticles which finally led to a separation of the areal distribution of these structures at F/C = 10. Such displacements did not occur in unfixed microsomes and were prevented by glutaraldehyde fixation of the purified membranes.

F/C exceeding 2 progessively and temperature-dependently inhibited the Na/K-ATPase in its membrane-bound states, whereas the solubilized enzyme was rather insensitive. The structural and biochemical data suggest that inhibition results from the perturbation of the lipidic microen­ vironment of the enzyme caused by filipin-cholesterol complexation.
Incorporation of a Voltage Sensitive Pore from Guinea Pig Heart Mitochondria into Black Lipid Membranes and Characterization of Electrical Properties
Authors: Schreibmayer W. , Hagauer H. , Tritthart H. A.
Published: August 2018

A pore from guinea pig heart mitochondria has been incorporated into BLM's (Black lipid membranes) in a highly oriented manner and its electrical properties studied. The pore shows multistate behaviour, the distribution of the pore between different conducting states being very sensitive to voltage. This has been proven by computation of single-pore experiments. Highest single pore conductance was 4.5 nSi in 1 ᴍ KCl, independent of voltage and with no detectable preference for cations or anions. The pore from guinea pig heart mitochondria reacts more sensitivly to voltage than pores of mitochondria from other tissues so far incorporated into BLM's.
Conical Kinetochores with Single Microtubules in the Micronuclear Mitosis of the Ciliate Colpoda steinii
Authors: Kuck A. , Ruthmann A.
Published: August 2018

During micronuclear metaphase, the decondensed chromosomes bear conical kinetochores connected by a single microtubule to the tapered ends of the spindle-shaped nucleus. Using Bernhard's procedure for the pre­ ferential staining of ribonucleo-protein-containing struc­ tures, the whole kinetochore cone retains its electron density. Chromosome separation at anaphase involves shortening of the kinetochore microtubule and elongation of the interpolar region.
Antifungal Phytoalexins in Phaseolus aureus Roxb
Authors: O’Neill Melanie J. , Adesanya Saburi A. , Roberts Margaret F.
Published: August 2018

Eight phytoalexins have been isolated from Phaseolus aureus (mung bean) seedlings after treatment with aqueous CuCl2. These compounds include three isoflavones: genistein, 2′-hydroxygenistein and a compound tentatively identified as 2,3-dehydrokievitone, four isoflavanones: dalbergioidin, kievitone, cyclokievitone and 5-deoxykievitone, and the pterocarpan phaseollidin. The antifungal activities against Cladosporium cucumerinum were determined.
Aureol and Phaseol, Two New Coumestans from Phaseolus aureus Roxb
Authors: O'Neill Melanie J.
Published: August 2018

Two new coumestans, aureol and phaseol, isolated from Phaseolus aureus have been charac­terized as 1,3.9-trihydroxycoumestan and 3,9-dihydroxy-4-(γ,γ-dim ethylallyl)-coumestan, respectively.
Effects of Pyridazinone Herbicides during Chloroplast Development in Detached Barley Leaves II. Effects on Lipid Content, Fatty Acid Composition and Ultrastructure of Chloroplasts
Authors: Laskay G. , Lehoczki E. , Gulya K.
Published: August 2018

The effects of three differently substituted pyridazinone herbicides were studied on the lipid content, fatty acid composition of glycerolipids, fatty acid synthesizing capacity and ultrastruc­ture of chloroplasts after 72 h of greening of etiolated barley leaves. SAN 9789 caused a nearly threefold increase in the total fatty acid content of chloroplasts. and this increase was accom­panied by an increase in the DGDG- and phospholipid-content as well. SAN 6706 and 9785 caused reduction in the linolenic to linoleic acid ratio in nearly all lipid classes, only PC was unaffected. Both herbicides reduced the saturated to unsaturated ratio in the PG, SAN 9789 had no effect on the fatty acid composition of the PG. Fatty acid synthesis was inhibited in the SAN 6706- and 9789-treated leaves as monitored by incorporation of labelled acetate, but all of the three pyridazinones stimulated the incorporation of labelled galactose into chloroplast galactolipids. SAN 6706 and 9789 also caused abnormal organization of chloroplast lamellar system.
Composition of the Heterogeneous Sex Attracting Secretion of the Dung Beetle, Kheper lamarcki
Authors: Burger B. V. , Munro Zenda , Röth Marina , Spies H. S. C. , Truter Verona , Tribe G. D. , Crewe R. M.
Published: August 2018

The white flocculent sex attracting secretion produced by the male dung beetle, Kheper

lamarcki MacLeay, was found to consist of tubular polypeptide fibres containing hexadecanoic acid, 2,6-dimethyl-5-heptenoic acid and (E)-nerolidol as major components, while a trace of skatole is responsible for the unpleasant odour of the secretion.
Notizen: ESR Investigations on the M odification o f the Ascorbic Acid-Erythrocyte Interaction by Ferrous Ions
Authors: Lohmann W. , Kiefer B. , Holz D. , Schmidt D. , Schreiber J.
Published: August 2018

An ascorbic acid-erythrocyte interaction results in the formation of the semidehydroascorbate (SDA) radical and an increase in spin concentration. Addition of a more than ten-fold concentration of Fe2+ (as FeSO4) to such a system compensates the effect produced by ascorbic acid, that is the electron spin resonance spectrum obtained resembles very closely that of erythrocytes only. With the dis­appearance of the SDA radical a high spin ferric ion signal appears concomitantly at g = 4.3.
A Non-Thermal Effect of Millimeter Wave Radiation on the Puffing of Giant Chromosomes
Authors: Koschnitzke C. , Kremer F. , Santo L. , Quick P. , Poglitsch A.
Published: August 2018

A non-thermal influence of millimeter wave radiation (swept in frequency from 64.1 GHz to 69.1 GHz, sweep­time 6 s, and with stabilized frequencies of 67.200 ± 0.001 GHz and 68.200 ± 0.001 GHz, power density S≦ 6 mW/cm2) on the puffing of giant chromosomes of the midge Acricotopus lucidus (Diptera, Chironomidae) was found. The effect is manifested as a reduction in size of a specific puff that expresses genes for a secretory protein. The non-thermal nature of the effect was proved by experiments in which the sham-exposed sample was warmed up by 2.5 °C which is more than the eight-fold microwave induced temperature increase of ≦0.3°C. Concerning the very low photon energy of mm-waves compared to the thermal energy kT, it seems likely that the coherence of the radiation is essential for the observed effect.
Cyanoacrylate Inhibitors of Photosynthetic Electron Transport. Nature of the Interaction with the Receptor Site
Authors: Phillips John , Huppatz John
Published: August 2018

The inhibitory activities (pI50 values) of a series of 3-alkylamino-2-cyanoacrylic acid ester derivatives in relation to photosypthetic electron transport in isolated pea chloroplast suspensions are reported. Assuming such pI50 values reflect the relative binding affinities for the inhibitor receptor site, the results suggest that several groups in these molecules interact specifically with the binding domain so that a multi-point attachment is formed. Stereochemical factors appear to play a significant role in the interaction.
A Nitroxide Diuron Analog as a Probe for the Mode of Action of Herbicides
Authors: Siderer Yona , Lavintman Nelly , Gilon Chaim , Ohad Itzhak
Published: August 2018

A new spin label nitroxide which is also a herbicide of the urea family has been synthesized. The nitroxide spin label derivative of diuron (ditempuron, DTPU) inhibits electron flow at the site of diuron inhibition of photosystem II (PSII) activity, and it is also reduced by electron flow from one of the first acceptors of PSII. The reduction of the nitroxide group of DTPU is inhibited by diuron or by trypsin treatment of the thylakoids but not by DNP-INT or DBMIB. It is suggested that DTPU binds specifically to and accepts electrons at the Qв site.
Measurements of Penetration and Detoxification of PS II Herbicides in Whole Leaves by a Fluorometric Method
Authors: Voss M. , Renger G. , Gräber P. , Kötter C.
Published: August 2018

The effect of herbicides that inhibit the photosynthetic electron transport at the photosystem II acceptor side has been analyzed in whole plants by using a fluorometric method. The data reported indicate that the apparent variable fluorescence of the induction curve normalized to the control value provides reliable information about the penetration rate and metabolic detoxification of PS II herbicides in whole plants.
Studies on the Functional Mechanism of System II Herbicides in Isolated Chloroplasts
Authors: Renger G. , Hagemann R. , Vermaas W.F.J.
Published: August 2018

The effect of specific proteolytic enzymes on variable fluorescence, p-benzoquinone-mediated oxygen evolution, PS II herbicide (atrazine and bromoxynil) binding, and protein degradation has been analyzed in isolated class II pea chloroplasts.

It was found that:

1. Trypsin and a lysine-specific protease effectively reduce the maximum chlorophyll-a fluorescence yield, whereas the initial fluorescence remains almost constant. At the same number of enzymatic activity units both proteases have practically the same effect.

2. Trypsin and a lysine-specific protease inhibit the p-benzoquinone-mediated flash-induced oxygen evolution with trypsin being markedly more effective at the same number of activity units of both enzymes. Unstacked thylakoids exhibit a higher sensitivity to proteolytic degradation by both enzymes.

3. Trypsin and a lysine-specific protease reduce the binding capacity of [14C]atrazine, but enhance that of [14C]bromoxynil (at long incubation times trypsin treatment also impairs bromoxynil binding). At the same specific activity a markedly longer treatment is required for the lysine-specific protease in order to achieve the same degree of modification as with trypsin.

4. Trypsin was found to attack the rapidly-turned-over 32 kDa-protein severely, whereas the lysine-specific protease does not modify this polypeptide. On the other hand, the lysine-specific protease attacks the light harvesting complex II.

5. Under our experimental conditions an arginine-specific protease did not affect chlorophyll-a fluorescence yield, p-benzoquinone-mediated oxygen evolution, herbicide binding and the poly- peptide pattern.

Based on these results a mechanism is proposed in which an as yet unidentified polypeptide with exposable lysine residues, as well as the lysine-free “QB-protein” regulate the electron transfer from Q-
A to QB and are involved in herbicide binding.
Comparison of Bicarbonate Effects on the Variable Chlorophyll a Fluorescence of CO2-Depleted and Non-CO2-Depleted Thylakoids in the Presence of Diuron
Authors: Blubaugh Danny J. , Govindjee
Published: August 2018

Evidence is presented from chlorophyll a fluorescence transient data for two sites of bicarbonate (HCO-
3*) action in photosystem II. Both the absence of HCO-
3 (HCO-
3-depleted thylakoids) and a high concentration of HCO-
3 (60 mм HCOj added to non-depleted thylakoids) accelerate the variable chlorophyll a fluorescence rise in the presence of 10 μм diuron (DCMU). In non-HCO-
3-depleted thylakoids the effect is independent of the order in which HCO-
3 and DCMU are added, whereas in HCO-
3-depleted thylakoids, the effect is seen only when HCO-
3 is added before DCMU. We propose that the effect seen in HCO-
3-depleted thylakoids is indirectly due to the binding of HCO-
3 functionally near the site of DCMU binding, which is also where HCO-
3 exerts its major effect on electron transport between the primary quinone QA and the plastoquinone pool. We suggest that the smaller effect seen in non-HCO-
3-depleted thylakoids is due to the binding of HCO-
3 at a second, lower affinity site. Binding at this site appears to require light, in con- trast to the higher affinity site, which is inhibited by light. Bathocuproine, an inhibitor of the H2O- to-silicomolybdate partial reaction, is synergistic with HCO-
3 in its effect on the variable chlorophyll a fluorescence of non-HCO-
3-depleted thylakoids, and may bind heterotropically with HCO-
3. Thus, this second site of HCO-
3 binding appears to be functionally near the bathocuproine binding site.
Herbicide and Plastoquinone Binding to Photosystem II
Authors: Oettmeier Walter , Soil Hans-Joachim , Neumann Eva
Published: August 2018

In plastoquinone-depleted thylakoids “DCMU-type” herbicides generally have a lower binding affinity as compared to control thylakoids, with the exception of DCMU itself. Contrary, binding properties of phenolic herbicides are not affected by plastoquinone depletion. DCMU in plastoquinone-depleted thylakoids can be displaced from the membrane by various substituted 1,4-benzoquinones, including plastoquinone-1. Labeling patterns by azido-atrazine are compared for thylakoids, plastoquinone-depleted thylakoids, and different photosystem II preparations from spinach and Chlamydomonas. Azido-atrazine tags a 32-34 kDa protein, which seems to be different from another 32-34 kDa protein which is preferentially labeled by a plastoquinone-azide.
Metribuzin-Resistant Mutants of Chlamydomonas reinhardii
Authors: Pucheu N. , Oettmeier W. , Heisterkamp U. , Masson K. , Wildner G.F.
Published: August 2018

Herbicide resistance in Chlamydomonas reinhardii cells was induced by mutagenesis with 5-fluorodeoxyuridine and ethylmethanesulfonate. Four mutant strains were isolated and analyzed for resistance against DCMU-type or phenolic inhibitors of photosynthetic electron transport.

The mutants were different in both the extent and the pattern of their resistance: the R/S value, i.e. the ratio of I50 values of the inhibition of photosynthetic electron transport in isolated resistant and susceptible thylakoids, varied for metribuzin from 10 000 to 36. The mutant MZ-1 was resistant against metribuzin, atrazine and DCMU, whereas the mutant MZ-2 showed resistance mainly against metribuzin and atrazine. The mutant MZ-3 was similar to MZ-1, but showed a lesser extent of resistance against DCMU. The mutant MZ-4 showed resistance against metribuzin, but not against atrazine. These results demonstrate that the resistance against one herbicide of the DCMU-type (metribuzin) must not be accompanied by similar resistance against te other inhibitors. Binding studies with radioactively labeled herbicides, [14C]metribuzin, [14C]atrazine and [3H]DCMU, and isolated thylakoids supported these observations.

Phosphorylation of thylakoid membrane proteins was studied with wild-type cells and resistant mutants under in vivo conditions in the light. The 32P-labeled main proteins bands were in the molecular weight range of 10-14 kDa, 26-29 kDa, 32-35 kDa and 46-48 kDa. The pattern and the extent of incorporation of 32P were similar for the mutants and the wild-type cells.
Inhibition of Carotene Biosynthesis in Cell Extracts of Phycomyces blakesleeanus
Authors: Bramley Peter M. , Clarke Ian E. , Sandmann Gerhard , Böger Peter
Published: August 2018

Cell extracts of the C115 (β-carotene-accumulating) strain of Phycomyces blakesleeanus were incubated with either [2-14C]MVA or [1-14C]IPP and a range of possible inhibitors of carotenogenesis, including bleaching herbicides, biphenyl compounds and geranylacetone. Several of these compounds were potent inhibitors of β-carotene formation and caused the accumulation of phytoene. No other carotenes were found to accumulate, in vitro.The structures of these inhibitors, compared to that of phytoene, suggest that they affect the enzymic activity of “phytoene dehydrogenase”, possibly by competitive inhibition.
Chloroplast Biogenesis, Its Inhibition and Modification by New Herbicide Compounds
Authors: Lichtenthaler Hartmut K.
Published: August 2018

Biogenesis and development of chloroplasts are summarized in the light of new findings; the interactions of different groups of photosynthetic herbicides with chloroplast development are indicated. The effect of two new active ingredients, mevinolin* and sethoxydim **, on chloroplast modification and biogenesis are described. Mevinolin blocks the cytoplasmic HMG-CoA reductase and sterol accumulation and modifies chloroplast differentiation via the formation of a sun-type chloroplast. Sethoxydim inhibits leaf growth in grasses and gramineous crop plants and strongly affects chloroplast biogenesis and differentiation at all stages of development from proplastids via prochloroplasts to young and mature chloroplasts. This applies to thylakoid formation and multiplication, grana formation as well as chloroplast division and chlorophyll and carotenoid accumulation. The chlorophyll fluorescence induction kinetics (Kautsky effect) indicate that photosynthesis is not affected. At higher doses sethoxydim stops all growth responses of maize plants and induces the accumulation of anthocyanins.
Pflanzliche Insektizide II [1]. Das ätherische Öl aus Blättern des Balsamkrautes, Chrysanthemum balsamita L. .Insektizide Wirkung und Zusammensetzung / Herbal Insecticides II [1]. The Essential Oil from Leaves of Chrysanthemum balsamita L.. Insecticidal Activity and Composition
Authors: Bestmann Hans Jürgen , Claßen Beate , Kobold Uwe , Vostrowsky Otto , Klingauf Fred , Strobel Harald , Knobloch K.
Published: August 2018

The essential oil from leaves of Chrysanthemum balsamita L. was analyzed by GC and GCMS techniques. About 30 components have been identified. The oil revealed insecticidal properties against aphids. Very little phytotoxicity was observed. The insecticidal activity could not be attributed to one of the single main substituents of the oil.
Time-Resolved Polarized Fluorescence of C-Phycocyanin and Its Subunits from Mastigocladus laminosus
Authors: Hefferle P. , Geiselhart P. , Mindl T. , Schneider S. , John W. , Scheer H.
Published: August 2018

The influence of aggregation and temperature on the excited state kinetics of C-phycocyanin from Mastiqocladus laminosus has been studied. Polarized fluorescence decay curves have been recorded using a synchronously pumped dye laser in conjunction with a synchroscan streak camera. The experimental data for all samples can be fit satisfactorily assuming a biexponential decay law. Fluorescence depolarization times have been interpreted in terms of energy transfer among the different chromophores. The influence of temperature is only moderate on the intra­molecular relaxation, but pronounced on the rates of energy transfer. Both are dependent on the size of the aggregate. The biexponential decay of the α-subunit containing only one chromophore, indicates the presence of different subsets of chromophores in these samples. The results are discussed in terms of variations of the chromophore arrangements upon temperature induced changes in the protein conformation.
Purification of Soybean DNA-Dependent RNA Polymerase I on a Column of Plasmid pHFK 206 Covalently Attached to Agarose
Authors: Grossmann Klaus , Friedrich Harald , Seitz Hanns Ulrich
Published: August 2018

The plasmid pHFK 206 consisted of plasmid pBR 322 and an 1.3 × 10-6 D insert, a cloned seg­ment of a soybean rRNA repeating unit with a preferential binding region for soybean RNA polymerase I, was coupled to cyanogen bromide activated agarose (Sepharose 4B) and used for affinity chromatography of RNA polymerases.

It could be shown by elution profiles and sodium dodecylsulphate/polyacrylamide slab gels that highly purified RNA polymerase from Escherichia coli MRE 600 bound to pHFK 206- Sepharose as holoenzyme with an apparently full complement of σ-subunit. With initially purified soybean RNA polymerase I from chromatin of 2,4-D treated hypocotyls it was demonstrated that pHFK 206-Sepharose could be used as an affinity chromatography method for purification of soybean RNA polymerase I in high degrees and economy of time.
Thermal Diffusion as a Mechanism for Biological Transport
Authors: Bonner Francis J. , Sundelöf Lars-Olof
Published: August 2018

Accumulated experimental information is used to assess the possible significance of thermal diffusion to mass transport in living matter. Possible thermal gradients across membranes, a single living cell, and an ensemble of such cells (e.g. an organ, tumor, etc.) are estimated. The corresponding model calculations, although not describing the biological process in detail, lead to conclusions about the possibilities for thermal diffusion as follows. Adequate thermal gradients to support substantial thermal diffusion could exist across biological membranes. Thermal diffusive flow would become significant when ordinary Fickian diffusion is sufficiently sup­pressed, e.g. in more concentrated systems near critical points of solution (i.e. near incipient phase separations). Conditions favorable to thermal diffusion functioning as a mechanism for active transport appear possible. Thermal diffusion appears much more important for transport into and out of an ensemble of cells than into or out of a single cell. Such mass transport by thermal diffusion could assume a sizable magnitude for an ensemble of cells with the dimensions of an organ or a tumor.