bluuebunny/crossref_metadata_2025 huggingface dataset:
The Interaction of Calf Thymus DNA with Mercuric Acetate and 3,6-Bis-(acetatomercurimethyl)-dioxane. Small-Angle X-Ray Scattering and Viscosity Studies
Authors: Zipper Peter , Ribitsch Gertraud , Schurz Josef , Bünemann Hans
Published: August 2018

The binding of Hg2+ and 3,6-bis-(acetatomercurimethyl)-dioxane (BAMD) to sonicated calf thymus DNA was studied by small-angle X-ray scattering and viscosity measurements. The scat­tering experiments with DNA complexed by different amounts of mercurials (for Hg2+ rb = 0-0.79, for BAMD rb = 0-0.86 mol of mercurial bound per mol of base pairs) established that the rod-like character of the DNA molecules is maintained up to high binding ratios. They revealed further a steady decrease of the cross-section radius of gyration Rc for the DNA · Hg2+ complex and a similar decrease of Rc for the DNA · BAMD complex up to rb = 0.35. This behav­iour is certainly caused by the incorporation of both mercurials near the axis of the DNA helix. Binding of BAMD at rb > 0.35 led to an increase of Rc which behaviour obviously reflects the lo­cation of mercury atoms at large distances from the axis, possibly on the surface of the helix. The increase of the mass per unit length Mc upon binding of the mercurials was found to be much higher than expected. This finding established that the length of the DNA helix decreases by 0.10±0.01 nm per bound mercurial at low binding ratios (i.e. up to rb = 1/3 for BAMD, up to possibly rb = 0.5 for Hg2+). A similar conclusion was also drawn from the observed decrease of intrinsic viscosity [rj] with increasing rb. The analysis of Mc at high binding ratios suggests that every BAMD molecule bound beyond rb=1/3 decreases the length of the DNA by 0.21 ±0.05 nm whereas Hg2+ when bound beyond rb = 0.5 causes no change of the length.
Carotenoid Composition of Chlorophyll-Carotenoid-Proteins from Radish Chloroplasts
Authors: Lichtenthaler Hartmut K. , Prenzel Ursula , Kuhn Gertrud
Published: August 2018

The uneven distribution of carotenoids and chlorophylls between several chlorophyll- carotenoid-proteins isolated from radish chloroplasts by SDS-polyacrylamide-gel electrophoresis is described.

Lutein and neoxanthin are enriched in the light-harvesting chlorophyll a/b-protein LHCP3, which exhibits low chlorophyll a/b ratios (1.1-1.3) and high values for the ratio chloro­phyll a/β-carotene (a/c = 60-180).

β-carotene is bound not only to the chlorophyll a-protein CPI + CPIa of photosystem I, but also to the chlorophyll a-protein CPa. Both chlorophyll a-proteins are characterized by high values for the ratio a/b and low values for the ratio a/c.
Carotenoid Biogenesis in the Stick Insect, Carausius morosus, during a Larval Instar
Authors: Kayser Hartmut
Published: August 2018

[14C]β-Carotene was fed to juvenile stick insects, Carausius morosus, of the fifth instar. Radioactivity was incorporated into 2-hydroxy-, 2-oxo-, and 3,4-didehydro-2-oxo-carotenoids of the β,β-type. These transformations are due to the insect’s own capacity; any contribution by microbial symbionts can be ruled out. A study on the labelling kinetics clearly shows that the biogenesis of hydroxy- and oxo-carotenoids is correlated to a decrease in the carotene precursor, but only up to mid instar. Thereafter, oxidation of the carotene is very low but the transformations of its metabolites continue as before. Predominantly β,β-carotene-2,2'-diol is dehydrogenated to 3,4,3',4'-tetradehydro-β,β-carotene-2,2'-dione via two hydroxyketones. This discontinuous utilization of β-carotene could be due to a stop at mid instar either in the oxidation or in the absorption in the gut of this precursor.
Hydroxyrutacridon-Epoxid, ein neues Acridon-Alkaloid aus Ruta graveolens / Hydroxyrutacridone Epoxide, a New Acridone Alkaloid from Ruta graveolens
Authors: Eilert U. , Wolters B. , Nahrstedt A. , Wray V.
Published: August 2018

Hydroxyrutacridone epoxide was isolated from roots and callus tissue cultures of Ruta graveolens L. and identified by spectroscopic methods by comparison to rutacridone epoxide.
Über die Biogenese von Aromastoffen bei Pflanzen und Früchten, XVII* Anabole Leistung von Erdbeerfruchtgewebe bei der Biosynthese von Aromastoffen / On the Biogenesis of Aroma Compounds in Plants and Fruits, XVII * Anabolic Properties of Strawberry Fruit Tissue for the Biosynthesis of Aroma Compounds
Authors: Drawert Friedrich , Berger Ralf G.
Published: August 2018

Slices from ripe strawberry fruit (in shape of segments) metabolize exogenous ʟ-alanine, acetate, pyruvate, n-butyrate, 2-ketovalerianate, n-butanal, n-hexanoate or d,l-mevalonic acid-δ-lactone to yield fruit-typical aroma compounds and some of them to considerable extent. Employing standard-controlled aroma separation by liquid-liquid-extraction, as well as prefrac­tionation on silica gel, the aroma components were determined by GC and GC-MS. Alkyldonors were converted more quickly and selectively than acyldonors, the former resulting in twenty-to thirtyfold increase in some of the concentrations of fruit-esters under specific conditions. The increase in ester biosynthesis ʟ-alanine is directly proportional to the concen­ tration of substrate up to 3 mmol/1. After addition of the above mentioned precursors the con­ centration of (+)-nerolidol, a terpenoid compound o f strawberry aroma, is increased.
The Triton X-100 and High Salt Resistant Residue of Saccharomyces cerevisiae Nuclear Membranes
Authors: Mann Karlheinz , Mecke Dieter
Published: August 2018

Saccharomyces cerevisiae nuclear membranes were prepared from isolated nuclei by digesting chromatin with deoxyribonuclease after an initial treatment of nuclei with very diluted buffers. When the nuclear membranes were treated with 5% Triton X-100 and 1 ᴍ NaCl an insoluble fibrous net was obtained which consisted mainly of protein with Mr values of 85000, 48000, 45000, 39000 and 31000. Lamins, a set of proteins with Mr = 65000-75000, which were shown to be the major proteins of the insoluble nuclear membrane residue of higher eukaryotes, were not found.
Alanine Dehydrogenase from Bacteroids and Free Living Cells of Rhizobium japonicum
Authors: Müller Peter , Werner Dietrich
Published: August 2018

Alanine dehydrogenase (E.C. 1.4.1.1.) from nitrogenase repressed free living cells of Rhizobium japonicum 61-A-101 was purified 370 fold to a specific activity o f 30.4 (μmol pyruvate · min-1 · mg protein-1. The same enzyme from effective bacteroids from nodules of Glycine max var. Mandarin, infected with the same strain was purified 150 fold to a specific activity of 35 units. The enzyme from both preparations was identical in the molecular weight of about 168 kD with four identical subunits of 42 kD. The alanine dehydrogenase is, therefore, different from the same enzyme from Bacillus subtilis (molecular weight 228 kD) and from Anabaena cylindrica (molec­ ular weight 270 kD). The Kᴍ data for the enzyme from Rhizobium japonicum are: 4.7 mmol/l for NH+
4 0.68 mmol/l for pyruvate and 44 μmol/l for NADH. Specific activity of the enzyme in total cell extracts from eight other strains of Rhizobium japonicum (3 effective strains, 5 ineffective strains) was only 20 to 30% o f the activity with strain 61-A-101. No correlation between alanine dehydrogenase activity and nitrogenase activity in these other eight strains was observed. The function of alanine dehydrogenase in Rhizobium japonicum in ammonium assimilation and cell wall differentiation is discussed.
Über die taxonomische Stellung der Hypocomidae (Ciliata) / On the Taxonomie Position of Hypocomidae (Ciliata)
Authors: Grell Karl G. , Meister Anne
Published: August 2018

Ultrastructural features of the ciliate Hypocoma acinetarum, an ectoparasite of the suctorian Ephelota, led to the conclusion that the Hypocomidae do not belong to the Cyrtophorida, as some authors suggested, but should be reunified with the Ancistrocomidae in the taxon Rhynchodida (Chatton et Lwoff).
Further Observations on the Source of Nitrogen in Phenazine Biosynthesis
Authors: Römer A. , Herbert R. B.
Published: August 2018

It is concluded from experiments with (S)-[CO15NH2]glutamine and [15N]ammonium sulphate that the biosynthesis of iodinin (1), in Brevibacterium iodinum, and of phenazine-1-carboxylic acid (7), in Pseudomonas aureofaciens, is primarily from a single nitrogen source (glutamine) and that the phenazines are constitued by combination of two units of the same precursor, as. 5. Some observations are made on the inhibition and triggering of iodinin biosynthesis.
Photosynthetic Adaptation in Synechococcus Cells
Authors: Döhler Günter , Leclerc Jean-Claude
Published: August 2018

The cyanobacterium Synechococcus (Anacystis nidulans, strain L 1401-1) grown under different light conditions showed variations in pigmentation. Ratios of photosynthetic pigments and the effect on quantum requirement and oxygen evolution were studied. An increase in the ratio of chlorophyll a forms with absorption maxima in the far red regime to total chlorophyll a forms was observed in cells grown in strong white light. The quantum efficiency of orange light (637 nm) - absorbed by phycocyanin - was higher after growth of Synechococcus in white than
Interrelationship between Quinolizidine Alkaloid Producing Legumes and Infesting Insects: Exploitation of the Alkaloid- Containing Phloem Sap of Cytisus scoparius by the Broom Aphid Aphis cytisorum
Authors: Wink Michael , Hartmann Thomas , Witte Ludger , Rheinheimer Joachim
Published: August 2018

Aphids (Aphis cytisorum) which infest broom plants (Cytisus scoparius) accumulate up to 500 μg alkaloid/g fr. wt. The alkaloids, which are similar to those of the plants, consist of 17-oxo-sparteine, sparteine, 12,13-dehydrosparteine, and lupanine. Infested plants contain > 50% less alkaloids than aphid-free plants. In Lupinus aphid resistance which is due to their high alkaloid content is more expressed: Whereas bitter varieties are free from aphids, only the sweet alkaloid-free plants are susceptible to aphid infestation. The accumulation of alkaloids in aphids indicates that the quinolizidine alkaloids are translocated via the phloem in legume plants. This assumption is supported by direct evidence: analysis of phloem sap from Lupinus contains up to 5 mg alkaloid whereas xylem sap is virtually free of alkaloids. The interrelationship between quinolizidine alkaloids and hervivores is discussed.
Multicomponent Mandibular Gland Secretions in Three Species of Andrena Bees (Hym., Apoidea)
Authors: Bergström Gunnar , Tengö Jan , Reith Wolfgang , Francke Wittko
Published: August 2018

50 volatile constituents of the mandibular gland secretions in males and females of three species of Andrena bees, A. wilkella (Chr.), A. ovatula (K .) and A. ocreata (K .), have been identified. The secretions are made up of a series of spiroacetals of four different systems together with mono-terpenes and unbranched acyclic compounds. Many of the components, particularly several of the dominant ones, occur in both sexes of all three species, so that the volatile secretions are qualita­tively very similar. Females contain about 100 μg per individuum , which is 3-5 times the amount of the males’ secretions. Major spiroacetals are E,E- and Z ,E-2,8-dimethyl-1,7-dioxa-spiro[5.5]undecane and E,E-and Z,E-2-ethyl-7-methyl-1,6-dioxaspiro[4.5]undecane, while prominent monoterpenes are geraniol and citronellol. Straight chain hydrocarbons C17, C19, C21 and C23 occur in fairly large amounts, mostly with increasing concentrations. With respect to the quantitative distribution of components of minor concentration, the bouquet of A. wilkella is clearly distinguishable from A. ovatula and A. ocreata which from the morphological and ethological point of view are more closely related. Behaviour tests with A. wilkella indicate high biological activity of the main spiroacetal.
Conformational Analysis of Benzyloxycarbonyl-Protected Peptides
Authors: Knack Ingo
Published: August 2018

The benzyloxycarbonyl (Z-) residue, an important protecting group in peptide synthesis, was introduced into the input data set of the “Empirical Conformational Energy Program for Peptides” (ECEPP) developed by Scheraga and coworkers. With additional modifications ECEPP is now prepared for conformational analysis of peptides containing this amino end group. Preferred conformations of the Z-residue were studied by performing calculations on Z-Gly methylamide. The results obtained may be applied to the conformational analysis of Z-protected peptides.
Immunochemical Characterization of Porphyridium cruentum B-Phycoerythrin: Proof of Cross-Reaction between Chromophore-Free Apoprotein and Holoprotein-Specific Antibodies
Authors: Sepp Eva , Wanner Gerhard , Eder Jörg , Köst Hans-Peter
Published: August 2018

Antibodies against phycobilisom es of Porphyridium cruentum immunoreact with B-phycoerythrin from the same organism. A strong antigen-antibody complex is not only formed with the native B-phycoerythrin but also when the chromophore is chemically reduced, split or even degraded with chromic acid. Characteristics of precipitations and dissolutions in the presence of the chaotropic reagents urea and potassium rhodanide are discussed for the immunocomplex with native B-phycoerythrin. A sandwich-type immunoadsorbent column appropriate for antigen-isolation is described; its binding properties are investigated biochem ically and by electron microscopy.
Release of K+ and H+ from Poly U in Aqueous Solution upon γ and Electron Irradiation.Rate of Strand Break Formation in Poly U
Authors: Bothe Eberhard , Schulte-Frohlinde Dietrich
Published: August 2018

Conductivity changes were found which followed the reaction of radiolytically generated OH radicals with the potassium salt of polyuridylic acid (poly U) in aqueous solution. After 60Co-γ-irradiation the observed increase of conductivity at pH = 6.8 was shown to consist of the liberation of K+ ions from the stock of K+ ions electrostatically bound to the polyanion. The initial G(K+) is 36 and hence 6 times higher than the G value of OH radicals in N2O saturated solutions. At a poly U concentration of 60 mgl-1 half of the ion release occurred at 12 J kg-1 and nearly all ions are released at 40 J kg-1. The liberation of K+ is explained to be a consequence of the formation of chain breaks leading to an increase of the degree of dissociation.

The rate of the ion release was studied under pulse radiolysis conditions. Because of the high G-vlaue of counterion liberation and the use of conductivity as analytical quantity the method is very sensitive. With 6 mgl-1 poly U the rate could be measured even at a dose per pulse of 0.25 J kg-1. The kinetics of the ion release can be described in terms of two parallel first order reactions of comparable contribution with an average rate constant of 0.8 s-1 at 20 °C, 60 mgl-1 poly U and pH = 6.8 with a small contribution of slower components. In more acidic solutions, besides K+ ions H+ are also liberated since at low pH values bound K+ is replaced by H+. The rate of the ion release was found to increase with increasing replacement of K+ by H+ (kobs = 100 s-1 at pH = 3.4, 60 mgl-1 poly U and T = 18 °C). With potassium ion free poly­ uridylic acid the corresponding rate constant amounted to 220 s-1, nearly independent of pH. From the temperature dependence activation parameters for the ion release were derived (Ea = 57 kJ mol-1, A = 1.0 x 1010 s-1 at pH = 6.8). Addition of p-benzoquinone at pH = 3.7 and dithiothreitol (DTT) at pH 6.8 were found to decrease the size of the conductivity changes and to increase the rate. The results show that p-benzoquinone and DTT react with poly U radicals and that these reactions prevent chain breaks and ion liberation.

It is concluded that the rate determining step of the conductivity increase is the formation of strand breaks by a cleavage of poly U radicals and that this reaction is pH dependent. The pH dependence and the observed value for the activation energy was found to be in agreement with the behaviour of a model system for the earlier postulated C-4′ mechanism for strand break formation of polynucleotides and DNA.
System Analysis of the Circadian Rhythm of Euglena gracilis, I. Linearities and Non-Linearities in the Response to Temperature Signals
Authors: Lork Wolfram , Kreuels Til , Martin Wolfgang , Brinkmann Klaus
Published: August 2018

The approach of control theory is used to describe the structure of the circadian system of Euglena gracilis. As a first step we discriminate linear and non linear properties of the dynamics.

The cellular motility as measured via long time records of sedimentation parameters in cultures is defined as the system output; sinusoidal temperature signals are used as input. By means of non stationary signal processing procedures we estimate gain and phase of the output signal. The problem of defining an appropiate gain of a cell suspension with an undefinite number of cells is solved by using the superimposition of two different input signals and by keeping one of them fixed as a reference signal.

Linear properties are shown with a linear frequency transfer and with the validity of the superposition principle at least within distinct regions of amplitude and frequency. Non linear properties are the signal distortion, the restriction of linear amplification to a distinct range of input temperature and the ambiguity of phase coupling near the circadian eigenfrequency.

The apparent lack of a limit of entrainment -an unexpected linear property - is explained by the masking effect of thermokinesis. A model is proposed describing the simultaneous control of motility by thermokinesis and the circadian system. On the base of that model further experiments are outlined.
Isolation of a b-Type Cytochrome Oxidase from Membranes of the Phototrophic Bacterium Rhodopseudomonas capsulata
Authors: Hüdig Hendrik , Drews Gerhart
Published: August 2018

A cytochrome oxidase (EC 1.9.3.1) was solubilized from the membrane fraction of aerobically grown cells of Rhodopseudomonas capsulata by treatment with Triton X-100. The enzyme was purified 160 fold by chromatography on DEAE-Sepharose CL-6B and affinity chromatography on cytochrome c-thiol activated Sepharose 4B.

The purified enzyme has a pH-optimum at 8.5 and a temperature optimum at 35 °C. The ap­ parent Km for reduced horse cytochrome c is 24 μм (at pH 8 and 30 °C). The purified cytochrome oxidase was 50% inhibited by 1.5 μм KCN and 10 μм NaN3. The purified enzyme contained one polypeptide of mr 65,000 and 6-type cytochrome.
Formation of Hydrocarbons by Photobleaching Cyanobacterium, A nacystis nidulans
Authors: Schmetterer Georg
Published: August 2018

The cyanobacterium Anacystis nidulans is bleached when subjected to both light and O2 to­ gether with suitable (pre)treatment o f the cells such as incubation at high (≧ 48 °C) or low (≦ 17 °C) temperatures, or in presence of metabolic inhibitors, or of substances forming com­ plexes with divalent cations. Concomitantly degradation o f the intracellular membranes is ob­ served (G. Schmetterer, G. A. Peschek, Biochem. Physiol. Pflanzen 176, 90-100 (1981)). The same three conditions cause formation of hydrocarbons, mostly ethane, a characteristic product of lipid peroxidation. Ethane production is unchanged and still light-sensitive even when no more pigments can be detected in the cells. In "white" cells light-dependent O2-uptake is also observed. The action spectrum of this process suggests that "completely" bleached cells retain very small amounts of residual chlorophyll, which must be unusually resistant to photooxidation.
Binding of Antibodies onto the Thylakoid Membrane VII. Localization of Coupling Factor of Photophosphorylation in the Lamellar System of Chloroplasts from Antirrhinum majus
Authors: Radunz Alfons , Meier Renate
Published: August 2018

The maximal binding of antibodies against the subunits of the coupling factor o f photo­ phosphorylation onto the ultrasonic sediment and to stroma-freed chloroplasts of Antirrhinum majus was determined. Different surfaces o f the thylakoid membrane are accessible to antibodies in both chloroplast preparations. Stroma-freed chloroplasts bind antibodies only at the outer surface, which is directed towards the stroma in intact chloroplasts. In the ultrasonic sediment, which is the product of ultrasonication and centrifugation, as was demonstrated by electronmicroscopy, the major part of the surface directed towards the inside of the thylakoids is accessible.

Both chloroplasts preparations are able to bind different amounts of antibodies to the five sub­ units of the coupling factor. While antigenic determinants of all five subunits are present on the surface directed to the outside, the δ-components seems to be lacking on the surface directed towards the inside. The α- and ε-component bind on both surfaces nearly the same amount of antibodies. Antigenic determinants of the β-subunit seem to exist in higher concentrations on the surface towards the outside and those of the γ-subunit on the surface towards the inside.

From the serological investigations it follows that coupling factor molecules span the thylakoid membrane from the outside to the inside. They are not only present in those parts of the thylakoid membrane, exposed in intact chloroplasts to the stroma, but also in stacked thylakoids. The differences between the results of other authors and the present results are discussed.
Use of Isolated Leaf Cells of A butilon theophrasti to Localize the Action of Two Aminotriazinone Herbicidal Derivatives
Authors: Hatzios Knton K.
Published: August 2018

The effects of the aminotriazinone herbicides metribuzin [4-amino-6-tert-butyl-3-(methylthio)-1,2,4,-triazin-5(4H)one] and metamitron [4-amino-3-methyl-6-phenyl-1,2,4-triazin-5(4H)-one] on the metabolism of enzymatically isolated leaf cells of Abutilon theophrasti Medic, were examined. Photosynthesis, protein, ribonucleic acid (RNA), and lipid synthesis were assayed by the in­ corporation of radioactive substrates such as NaH14CO3, [14C]leucine, [14C]uracil, and [14C]acetate, respectively, into the isolated cells. Photosynthesis was the most sensitive process inhibited by both herbicides, but metribuzin was a more potent inhibitor than metamitron. Protein synthesis was not affected by any herbicide. RNA synthesis was inhibited significantly by both herbicides and may be involved in their ultimate herbicidal action. Lipid synthesis was inhibited significantly only by the high concentrations of metribuzin, and it was not affected by any concentration of metamitron at any incubation time. Inhibition of lipid synthesis may be involved in the action of metribuzin as a herbicide.
Inhibition of Acetyl CoA Carboxylase by a High Molecular Weight Protein in Rat Liver
Authors: Abdel-Halim Mostafa N. , Yousufzai S. Y. K.
Published: August 2018

Acetyl CoA Carboxylase, Protein Inhibitor, Rat Liver A high molecular weight protein (approximately 1.5-2 × 106 daltons) has been found in rat liv­ er cytosol to inhibit acetyl CoA carboxylase activity. The protein inhibitor was purified by am­ monium sulfate precipitation, DEAE-cellulose chromatography and gel filtration. The inacti­ vation of the carboxylase is not attributable to either phosphorylation of the enzyme or to action on substrates or cofactors of the reaction. The activity of the inhibitor is destroyed by heating to 55 °C for 5 min, by treatment with trypsin, or by increasing bovine serum albumin in the reaction mixture. Hence it appears that the inhibitor is a regulatory protein that acts directly on acetyl CoA carboxylase.
Characterization of the Nuclear Lamina in an Insect by Differential Staining
Authors: Marx Ruth
Published: August 2018

The nuclear envelope of the larval fat body in the blow­ fly Calliphora vicina reveals a conspicuous nuclear lamina. It appears homogeneous, Fibrous or granular depending upon the fixing and staining methods. The best relative contrast for the nuclear lamina and the nuclear pore complex is obtained with a phosphotungstic acid staining procedure designed for proteins.
Versuche zur Synthese natürlich vorkommender prenylierter Naphthalinderivate. Nachweis eines neuen Prenylnaphthochinon- derivates in Galium mollugo / Synthesis of Naturally Occurring Prenylated Naphthalene Derivates. Isolation of a New Prenylnaphthoquinone from Galium mollugo
Authors: Heide Lutz , Leistner Eckhard
Published: August 2018

Several prenylated naphthalene derivatives were synthesized and characterized by spectroscopic methods. One of these compounds, 2-methoxycarbonyl-3-prenyl-1,4-naphthoquinone, was detected as a new natural product in the root system of Galium mollugo L. This new natural product is likely to be related to the biosynthesis of mollugin and anthraquinones.
Changes in the Fluorescence Emission Spectrum of Chlorella emersonii Induced by Cold Treatment; a Possible Regulative Feature of Energy Uptake
Authors: Harnischfeger G. , Jarry H.
Published: August 2018

Algae, when slowly cooled down to around -5 °C, undergo a change in the fluorescence emission spectrum subsequently taken at liqu. nitrogen temperature. This change resembles the magnesium effect described by Murata [BBA 189,171 - 181, (1969)] for isolated chloroplasts.

Evidence is shown, that both effects are indeed analogous. Cooling the organisms seems to in­ crease the permeability of the thylakoids for cations and, thus, a depletion with concomitant changes in membrane structure. The system serves as a model for the probable in vivo control of pigment interaction through alteration of membrane properties.
A Study of State Changes in Chlorella: The Effect of Uncoupler and Energy Transfer Inhibitors
Authors: Sane P. V. , Furtado D. , Desai T. S. , Tatake V. G.
Published: August 2018

Pre-illumination of Chlorella cells at room temperature with light primarily absorbed by PSII (650 nm) produces a state called state II. This is characterized by high fluorescence at 715 nm (high F715/F685) at liquid nitrogen temperature. Alternately if the cells are pre-illuminated by light primarily absorbed by PSI (710 nm) then state I with high fluorescence at 685 nm (low F715/ F685) at 77K is produced. We have investigated the role of photophosphorylation in the development of state I/II in chlorella cells using uncoupler and energy transfer inhibitors. The results suggested that the development of state I depends upon the energization of the membrane. Both DCCD and TPTC which permit build up of proton gradient block the adaptation to state I in­ dicating that proton gradient formation alone is not sufficient to develop state I. The data obtain­ ed by us as also published in the literature indicate that redox states o f the electron transport carriers are responsible for the development of state II.
Ca Entry and Contraction as Studied in Isolated Bovine Ventricular Myocytes
Authors: Isenberg Gerrit
Published: August 2018

Single bovine ventricular myocytes were superfused with Tyrode solution containing 1.8 mᴍ CaCl2. The cells did not bear external load and contracted isotonically. Contraction and relaxation were characterized by the shortening and relengthening of the sarcomeres which resembled in their time course the isometric twitches of bovine papillary muscles. Resemblance was also found in regard to positive inotropic interventions as increase in the stimulation frequency, exposure to elevated [Ca]0 or to adrenaline.

A two-microelectrode voltage-clamp technique was applied to the single myocyte. The trans­membrane Ca inward current ICa was defined as difference current sensitive to 5 mᴍ Ni or to 2 μᴍ D600. During a voltage step from -45 to + 5 mV, ICa peaked within 3 ms to -6 nA, afterwards it decayed to 15% of peak amplitude (incomplete inactivation with a 2 exponential time course). Experiments in Na-free media suggested that Na entry does not significantly contaminate ICa. Therefore, Ca entry could be calculated from ICa. The increment in total intra­ cellular Ca concentration (Δ[Ca]i
T) was estimated by referring Ca entry to the cell volume (50 pl).

Within 100 ms Δ[Ca]i
T came to 25 μᴍ at control conditions, to 55 μᴍ at [Ca]0 = 3.6 mᴍ and to 88 μᴍ when 0.1 μᴍ adrenaline were present. The Δ[Ca]i
T values were sufficient to activate contraction without the necessity of Ca-release from SR.

Despite the new data, the relationship between Ca entry and activation of contraction was complex: during the “positive Herztreppe” ICa slightly attenuated but contractility doubled. Therefore, the old EC-model (M. Morad and Y. Goldman, Progr. Biophys. Mol. Biol. 27, 257 (1973)) was adapted. The Ca-entry’s capability to load and to overload the intracellular Ca store (SR) is discussed.
Notizen: Synthesis of 6-Chlorogenistein
Authors: Lévai Albert , Tökés Adrienne L.
Published: August 2018

Chlorochalcone, Chloroisoflavone, Oxidation with Thallium(III) Nitrate An unambiguous synthesis of 6-chlorogenistein (5,7,4′-trihydroxy-6-chloroisoflavone) has been worked out via the oxidation of 2′-hydroxy-4,4′,6′-trimethoxy-5′-chlorochal-cone with thallium(III) nitrate followed by the demethylation of the 5,7,4′-trimethoxy-6-chloroisoflavone.
High-and Low-Affinity Binding of Photosystem II Herbicides to Isolated Thylakoid Membranes and Intact Algal Cells
Authors: Laasch Henrik , Pfister Klaus , Urbach Wolfgang
Published: August 2018

High- and low-affinity binding of photosystem II herbicides to isolated thylakoids of Spinacia oleracea and to intact cells of the unicellular green alga Ankistrodesmus braunii were investigated.

Complete mutual displacement of bound diuron-type herbicides (e.g. diuron, atrazine, terbutryn) by either diuron- or phenol-type herbicides (e.g. ioxynil, dinoseb) in thylakoids as well as in intact algal cells was found for herbicide concentrations (< 4 nmol bound herbicide/mg Chl) which gave almost saturated high-affinity binding. This demonstrates a high degree of specific binding of these herbicides towards their receptor sites even in intact algal cells. In contrast, phenol-type herbicides are largely unspecifically bound in algal cells.

The mechanism of binding of all photosystem II herbicides at the high-affinity (specific) binding site was found to be competitive. Within the group of diuron-type and of phenol-type herbicides as well as between these two groups, graphical and quantitative analysis of the Lineweaver- Burk plot and of the Dixon plot indicated competitive binding. From this a common binding site for both types of herbicides was concluded. The involvement of two different herbicide binding- proteins is discussed. Low-affinity (unspecific) binding was found to be irreversible in contrast to the easily reversible high-affinity binding. Irreversibility was indicated by a lack of displacement. It is proposed that low-affinity binding represents either a partitioning of the herbicides into the lipophilic parts of the membranes or an attachment to distinct receptor sites. Unspecifically bound herbicides might be responsible for several high concentration effects of the photosystem II herbicides, which are described in the literature. Evidences for the possible existence of a second binding site of these herbicides are presented.
A Cyanobacterial ATPase Distinct from the Coupling Factor of Photophosphorylation
Authors: Lockau Wolfgang , Pfeffer Susanne
Published: August 2018

A particle-bound, Mg2+ -dependent ATPase activity is investigated in cell-free extracts of the tyanobacterium Anabaena variabilis. The enzyme can be clearly distinguished from the cyanobacterial coupling factor of photophosphorylation and from the alkaline phosphatase. It requires low concentrations of Ca2+ for maximal activity and is inhibited by ortho-vanadate, indicating that the enzyme may form a phosphorylated intermediate in its catalytic cycle. The distribution of the ATPase in sucrose density gradients does not follow that of thylakoids. It is concluded from these characteristics that the enzyme is bound to the plasma membrane. The cytochrome oxidase activity of the extracts appears to be restricted to the thylakoids.
Sodium-Potassium Movement and the Regulation of Cardiac Muscle Activity
Authors: Daut Jürgen , Rüdel Reinhardt
Published: August 2018

The changes in intracellular sodium activity and contractility produced by short-lasting application of a fast-acting cardiac glycoside were measured in guinea-pig ventricular muscle. It was found that under certain conditions the change in twitch tension paralleled the change in sodium activity. It is suggested that the electrogenic sodium pump may be involved in the regulation of both the mechanical and the electrical activity of cardiac muscle.
5,7,3′,4′5′-pentahydroxyflavanone in the bracts of helichrysum bracteatum
Authors: Forkmann Gert
Published: August 2018

Chromatographic investigations on Helichrysum bracteatum revealed the presence of three flavanones in the bracts. Two of them were the well known flavanones naringenin and erio- dictyol. The third flavanone was identified as the hitherto in nature unknown 5,7,3′,4′,5′- pentahydroxyflavanone. This was accomplished by chromatographic and spectrophotometric comparison with an authentic sample prepared from 3,4,5,2′,4′,6′-hexahydroxychalcone-2′- glucoside. Moreover, precursor experiments with suitable white flowering mutants of Matthiola incana and Antirrhinum majus also confirmed that the third compound was identical with 5,7,3′,4′,5′-pentahydroxyflavanone.
The Intensity Dependence of the Receptor Potential of the Limulus Ventral Nerve Photoreceptor in Two Defined States of Light-and Dark Adaptation
Authors: Stieve H. , Bruns M. , Gaube H.
Published: August 2018

Receptor potentials of Limulus ventral nerve photoreceptors were evoked in reproducible states of moderate light- and considerable dark adaptation (LA, DA) with light stimulus intensities from threshold to saturation values using a repeated flash sequence.

With increasing light intensities latent period and time-to-peak shortened in the state of both LA and DA The decrease-time is prolonged by increasing stimulus intensities (LA and DA) and continues to rise even when the amplitude of the receptor potential is already saturated.

The sigmoid response height vs. log stimulus intensity curve is shifted upon LA towards higher stimulus intensities, and its steepness is increased. LA prolongs latent period and time-to-peak at low light intensities; at high light intensities, however, the DA-values are longer. The decreasetime of the receptor potential is always shorter in the light-adapted state.

The results are discussed according to the assumption that size and duration of the receptor potential are primarily determined by the distribution of bum p latencies. Changes of the receptor potential parameters are explained by changes of bum p size and of bum p latency distribution due to light adaptation.
Antibodies against the a-factor pheromone of saccharomyces cere visiae
Authors: Tillmann Ulrich , Hahn Heinz
Published: August 2018

The mating pheromone of baker’s yeast, the a-factor, is a dodeca-/tridecapeptide, which is not antigenic by itself. It was coupled to succinylated thyroglobulin by the carbodiimide procedure to facilitate selective coupling of the a-factor mainly by its N-terminal region. Antibodies against this conjugate were raised in rabbits. After selective precipitation of the rabbit antiserum with succinylated carrier prior to the radial double diffusion test (Ouchterlony) specific antibodies against the coupled a-factor could be detected
Enhancement of in-vitro Translation of Eukaryotic RNAs by Cyclic AMP
Authors: John M. E. , Knöchel W.
Published: August 2018

Addition of cyclic AMP to normal rabbit reticulocyte lysate brings about substantial increase in protein synthesis programmed by both nuclear and polysomal eukaryotic RNAs. The increase in synthesis is largely nonspecific and the in-vitro translation system is rendered viable for longer periods of time than in the absence of cyclic AMP. This stimulation of translation could be due to the inhibition of protein kinases that are initially activated by secondary structure of RNAs. However, the ability of cyclic AMP to further stimulate methyl mercury or heat denatured RNA indicates that additional mechanisms may be involved in the enhancement of translation
On a Quantitative Determination of Antibodies to Lipids and Proteins
Authors: Radunz A.
Published: August 2018

The amount of precipitating antibodies in monospecific lipid- and protein antisera was determined by quantitative precipitation reactions according to the methods of Heidelberger and Kendall. Antisera were obtained by immunization of rabbits. Fragments of the thylakoid membrane from Antirrhinum chloroplasts were used as antigens for the binding of antibodies. These fragments had a diameter of 100 Å. They were composed of 51% proteins and 39% lipids.

It was found that antisera to the lipids mono-, tri- and digalactosyl diglyceride, sulfoquinovosyl diglyceride and phosphatidyl glycerol contained 20 to 92 μg precipitating antibodies per ml serum. In antisera to the coupling factor of photophosphorylation, cytochrome f, a polypeptide with the apparent MW 24000 and a serum to the total protein of the lam ellar system 23 to 99 (ig were found. In chloroplast antisera the amount of all precipitating lipid- and protein antibodies amounted to 765 μg per ml. The described antisera originated from blood that had been withdrawn from the test animals 4 to 10 week after antigen injection
Vergleichende untersuchungen zur wehrchemie und drüsenmorphologie abdominaler abwehrdrüsen von kurzflüglern aus dem subtribus philonthina (coleoptera, staphylinidae) / Comparative investigations on defensive chemistry and gland morphology of abdominal defensive glands from rove beetles of the subtribe philonthina (coleoptera, staphylinidae)
Authors: Dettner Konrad
Published: August 2018

Within the rove beetle subtribe Philonthina (Staphylinidae) there are found paired abdominal defensive glands which show a bipartition and are characterized by an unique, evaginable evaporation tissue which is described for the first time. The gland chemistry is found to be characterized by at least 27 compounds. The main component is represented by the alkaloid actinidine, minor components are iridodial, three possible monoterpenoid iridodial precursors, an octadecenole and two series o f hydrocarbons and acetates which are partly branched and unsaturated. It could be shown, that the separated gland of the evaporation tissue, whose evagination was studied, has no different synthetic abilities as compared with the main gland system. Chemotaxonomic results according to Hennig’s principle reveal an isolated position of the rove beetle tribe Quediini within the subfamilies X antholininae and Staphylininae. The morphologically unique defensive gland of the Xantholininae may be homologized with other abdominal glands of the Staphylinina and Philonthina, based on the common presence of iridoid defensive components
Formation of Benzophenanthridine Alkaloids by Suspension Cultures of Eschscholtzia californica
Authors: Berlin Jochen , Forche Edgar , Wray Victor , Hammer Joachim , Hösel Wolfgang
Published: August 2018

Suspension cultures of Eschscholtzia californica accumulate the dihydro forms of the benzo- phenanthridine alkaloids sanguinarine, chelirubine, macarpine and chelerythrine, all of which are known to be constituents of the Eschscholtzia plant. Under most experimental conditions dihydrochelirubine was found to be the main constituent of the cultured cells. The specific yields of alkaloids varied from zero to 1.7% on a dry weight basis depending on the media conditions. The highest specific yield was 1.5 mg/g dry weight or 13 mg/1 with the growth medium B5. After transfer of the cells into the induction medium IM2 the alkaloid accumulation increased to 17 mg/g dry weight and 146 mg/1. The induction medium contained increased levels of sucrose, decreased levels of phosphate and was devoid of phytohormones. The effect of the various media conditions on the biosynthesis of phenolics was quite different to those found for the alkaloids.
Prunasin Biosynthesis by Cell-Free Extracts from Black Cherry (Prunus serotina Ehrh.) Fruits and Leaves
Authors: Poulton Jonathan E. , Shin Sun-In
Published: August 2018

Immature fruits and leaves of black cherry (Prunus serotina Ehrh.) accumulate the cyanogenic glucoside prunasin (the β-glucoside of (R)-mandelonitrile). Cell-free extracts from these tissues catalysed the stereospecific glucosylation of (R,S)-mandelonitrile to (β)-prunasin at rates of 0.2-2.0 μmol/h/mg protein. Uridine diphosphate glucose (Km = 0.32 mᴍ) acted as glucose donor. The optimum concentration of (R,S)-mandelonitrile was 20 mᴍ. Highest activity was exhibited at pH 7.0-8.0 in Tris-phosphate buffer, and no additional cofactors were required. β- Mercaptoethanol (14.5 mᴍ), provided in the homogenization medium to prevent browning of homogenates, did not stimulate the rate of prunasin production. In addition to (R)-mandelonitrile (100%), significant activity was shown towards mandelamide (21%), benzyl alcohol (15%), mandelic acid (8%) and benzoic acid (153%), but not towards prunasin. Mandelonitrile glucosyltransferase activity was most stable at - 20 °C in the presence of 10% glycerol.
Inability of Petite Mutants of Industrial Yeasts to Utilize Various Sugars, and a Comparison with the Ability of the Parent Strains to Ferment the Same Sugars Microaerophilically
Authors: Spencer J. F. T. , Spencer D. M. , Miller R.
Published: August 2018

A number of industrial strains of Saccharomyces cerevisiae were converted to the petite form and tested for the ability to utilize galactose, maltose, sucrose, α-methyl glucoside and raffinose. The parent strains all metabolized these sugars aerobically. Twelve of the petite forms did not utilize galactose, six failed to utilize maltose, 17 did not utilize x-methyl glucoside, and 18 did not utilize raffinose. The petites of two distiller’s yeast strains did not utilize sucrose. The respiratory-competent parent strains nearly all fermented galactose, maltose, sucrose and raffinose, though 19 strains did not ferment α-methyl glucoside microaerophilically. Three strains did not ferment galactose, two fermented it only after several days adaptation, one did not ferment raffinose, and two did not ferment sucrose under microaerophilic conditions. Six respiratory-competent strains which did not utilize galactose when in the petite form fermented higher (10%) concentrations of glucose and maltose under microaerophilic conditions, but only three of these fermented galactose. The implications of these findings for the use of such strains in industry are discussed briefly.
Bioalkylation of Nucleic Acids in Mice by Insecticides. I. Alkylation of Liver RNA and DNA by Chlorpyrifos
Authors: Mostafa I. Y. , Adam Yousr M. , Zayed S. M. A. D.
Published: August 2018

Male mice were i.p. injected with two doses (5&15 mg/kg body weight) of [1-14C]ethyl-labelled chlorpyrifos. The radioactivity in liver, fat, kidney and urine was measured 6, 24, 48, and 192 h after treatment. Liver RNA and DNA were isolated and hydrolyzed and the bases separated by ion-exchange chromatography. Radioactivity resulting from incorporation and alkylation of RNA and DNA was measured. Labelled 7-ethylguanine was found in RNA hydrolysate which amounted 5.5 × 10-3 calculated as fraction of the applied dose. In DNA hydrolysate [14C]7-ethylguanine was missing and the major radioactivity was found in two unknown peaks, one of which corresponds to 3 × 10-2 of the applied dose. The results indicate that the extent of alkylation obtained with clorpyrifos is high as compared with other organophosphates with methyl esters.
Verpacrocin, ein Polyenpigment aus Mycelkulturen von Verpa digitaliformis (Pers.) Fr. (Ascomycetes) [1] / Verpacrocin, a Polyene Pigment from Mycelial Cultures of Verpa digitaliformis (Pers.) Fr. (Ascomycetes) [1]
Authors: Besl Helmut , Bresinsky Andreas , Meixner Birgit , Mocek Ursula , Steglich Wolfgang
Published: August 2018

Mycelial cultures of the ascomycete Verpa digitaliformis produce a yellow pigment, verpacrocin. Its structure was determined by spectroscopic methods to be 2,4,6,8,10,12,14- hexadecaheptaenedial (3).
Separation, Purification, and Characterization of Two Isoforms of Glutamine Synthetase from Chlamydomonas reinhardii
Authors: Florencio Francisco J. , Vega José M.
Published: August 2018

Two isoforms of glutamine synthetase. GS1 and GS2, have been separated from Chlamydomonas reinhardii cells grown autotrophically with nitrate. The intracellular level of GS2 was higher than that of GS1. In cells under darkness, the GS1 peak increased markedly, whereas that of GS2 became negligible.

The two isoenzymes were purified to electrophoretic homogeneity by a method which included: a) DE-52 cellulose chromatography; b) ammonium sulphate fractionation: and c) affinity chromatography on ADP-sepharose. The specific activity was 114 and 63 U/mg for GS1 and GS2 respectively, and both enzymes (Mr = 380 000 and 373 000) are oligomeric proteins composed by 8 subunits of similar size (Mr = 48 000 in GS1, and 46 000 in GS2). The basic differences between GS1 and GS2 are: a) the effect of light on their intracellular level: b) their Km for ammonium (83 and 244 μᴍ, respectively). Both isoenzymes were inhibited in a similar extent by ʟ-alanine, ʟ-glycine and ʟ-arginine.
Ontogeny and Biosynthesis of Isovitexin 7-O-Galactoside in a Mutant of Silene pratensis Unable to Glycosylate this Compound in the Petals
Authors: Brederode J. van , Steyns J. M.
Published: August 2018

Enzyme activity responsible for the biosynthesis of isovitexin-7-O-galactoside from isovitexin and UDP-galactose can be demonstrated in protein extracts of cotyledons and rosette leaves from Silene pratensis plants. This galactosyltransferase activity is absent in stem leaves and petals. “True Km” values of 0.0025 mᴍ for isovitexin and of 8.2 mᴍ for UDP-galactose were found. At infinite concentration of both substrates the “true Vmax” value was 0.11 mᴍ/min/mg protein. The galactosyltransferase activity was optimal at pH 7.0; the divalent ions Zn and Hg were inhibitory, whereas Ca, Co, Mg, Mn and EDTA were not inhibitory.
Variable Fluorescence and Fluorescence Spectra of Algae after Herbicide-Induced Pigment Bleaching
Authors: Karapetyan Navassard V. , Strasser Reto , Boger Peter
Published: August 2018

Herbicides like norflurazon, oxadiazon, or oxyfluorfen affect the pigment apparatus of green algae. Their influence on variable (FmaK - F0) and initial fluorescence (F0) as well as on the state of chlorophylls were investigated. Two main modes of action of these herbicides on the photo­synthetic apparatus during growth have been found:

First: Scenedesmus cells grown with norflurazon. a carotene-biosynthesis inhibitor, show chlorophyll bleaching concurrently with decrease or inactivation of photosystem-II reaction centers, with small changes in fluorescence spectra. Further, electron transport is blocked at the acceptor side of photosystem II. Disappearance or inactivation of photosystem-II reaction centers after a 50% loss of chlorophyll is accompanied by a sharp increase of the F0 yield, with small changes in the chlorophyll state. The slow-decay phase in fluorescence induction of these cells, enhanced by dithionite, is ascribed to a reversible photobleaching of chlorophyll during the measurement.

Second: Oxadiazon and oxyfluorfen alter substantially the state of chlorophylls and cause strong bleaching, but reaction centers of photosystem II, although less than in control cells, are active even after an 80% disappearance of chlorophyll. The yields of F0 and (Fmax - F0) in treated cells are independent of the extent of chlorophyll bleaching. In contrast to norflurazon, the latter two herbicides do not inhibit carotenogenesis. Decrease of photosystem-II reaction centers may be due to non-specific pigment destruction (oxyfluorfen) or interference w'ith chlorophyll biosynthesis.