bluuebunny/crossref_metadata_2025 huggingface dataset:
Is Oxygen Consumption of Surviving Tissues Determined by the Oxygen Tension of the Suspension Medium?
Authors: Pichotka Josef Peter , Schmidt Hans Josef
Published: August 2018

Oxygen tension in the suspension medium and oxygen uptake of the isolated diaphragm of the mouse have been determined simultaneously with systematic variation of shaking frequency and oxygen concentration of the gas phase. Oxygen tension in the suspension medium readies its final value during the usual equilibration period of 10 minutes and remains constant for the whole measuring period. Each combination of shaking frequency and oxygen concentration of the gas phase results in a reproducible value of oxygen tension in the medium. Equal oxygen tension in the fluid phase can be attained by different combinations of shaking frequency and oxygen concentration of the gas phase. Oxygen uptake at the same oxygen tension of the suspension medium can be very different; it is the higher the higher the shaking rate in the combination. On the other hand the same oxygen consumption of the tissue samples can be observed with highly different oxygen tensions in the medium. It must be concluded from the data in this paper, that the influence of shaking rate per se on the oxygen uptake of isolated tissue can be of the same order as the influence of oxygen tension.
Spatial Structures in a Model Substrate-Inhibition Reaction Diffusion System
Authors: Mimura Masayasu , Murray J. D.
Published: August 2018

An important new model universal oscillator proposed by Seelig which depends on substrate inhibition is considered. In a finite spatial domain with zero flux boundary conditions and in which the substrates can diffuse it is shown that diffusion-driven instability is possible and can result in finite amplitude spatial structures. Illustrative numerical results are presented which exhibit this behaviour.
Zur Frage biogener Anreicherungen von Vanadium und Nickel in Pflanzen des Karbonzeitalters / The Question of Biogenous Enrichments of Vanadium and Nickel in Plants of the Carbon Age
Authors: Meisch Hans-Ulrich , Reinle Wolfgang , Richter Bernd-Arwed
Published: August 2018

Original carbonaceous material of fossile carbon plants from the divisions of the Equisetophyta (Calamariaceae), Lycophyta (Lepidodendraceae, Sigillariaceae), Filicophyta (Filicatae), and Spermatophyta (Pteridospermatae, Cordaitidae) was analyzed by atomic absorption spectroscopy on its content of the trace metals vanadium and nickel. The average V-content was found to be 10 to 100 fold higher than that of the neighbouring coal beds or that of the embedding materials, while the Ni-concentrations were found to be almost in the same range. The highest contents of V and Ni were found in the Calamariaceae and in the Pteridospermatae. The V-and Ni-contents of the fossile carbon plants are compared to those of related recent plant genera (clubmosses, horse­ tails, ferns), which were analyzed by 46 representative samples. A possible biogenous enrichment of V and Ni in plants of the carbon age is discussed.
The Role of Ubiquinone-10 in Cyclic Electron Transport in Rhodopsendomonas capsulata Ala pho+: Effects of Lyophilization and Extraction
Authors: Bowyer John R. , Baccarini-Melandri Assunta , Melandri B. Andrea , Crofts Antony R.
Published: August 2018

1. The effects of lyophilization and the extraction of ubiquinone-10 on the kinetics of electron transport in Rhodopseudomonas capsulata Ala pho+ have been investigated.

2. Lyophilization reduced the amount of ferrocytochrome c2 photo-oxidized on a microsecond time scale following a single excitation.

3. Lyophilization increased the reactivity of the electron transfer components with redox mediators, particularly N-methyl phenazonium methosulphate (PMS). At a concentration of 1 µᴍ , PMS accelerated reaction center re-reduction, ferricytochrome c2 re-reduction and ferrocytochrome b50 oxidation. The cytochrome c2 re-reduction stimulated by PMS was antimycin A insensitive but the cytochrome b50 oxidation was partially antim ycin sensitive.

4. Removal of 25- 30 molecules of ubiquinone 10 per reaction center removed a secondary acceptor pool, had very little effect on the kinetics of ferricytochrome b50 reduction and ferricyto­ chrome c2 re-reduction, but markedly inhibited ferrocytochrome b50 oxidation. Ubiquinone extraction also caused an increased stimulation of ferrocytochrome b50 oxidation by PMS.

5. The involvement of tightly bound ubiquinone in cytochrome b reduction and in the cytochrome b-c2 oxido-reductase, and the role of semiquinone species is discussed.
Notizen: Isolierung und Strukturaufklärung von 2′-Hydroxy-4′, 6′dimethoxychalkon-4-glukosid aus Viscum album L. / Isolation and identification of 2′-hydroxy-4′, 6′ -dimethoxy-chalkon-4-glucoside of Viscum album L.
Authors: Becker Hans , Exner Joachim , Schilling Gerhard
Published: August 2018

A hitherto unknown chalkon (2′-hydroxy-4′,6′-dimethoxy-chalkon-4-glucoside) of European mistletoe (Viscum album L.) has been isolated and identified.
Notizen: Terpenic Constituents of Asarum
Authors: Hayashi N . , Sdiolichin M. , Komae H. , Sakao T.
Published: August 2018

Terpenic constituents of 23 species of subgenus Heterotropa growing in Japan were analyzed by means of gaschromatograph-mass spectrometer. Thirteen sesquiterpenes were identified from the essential oils together with fourteen monoterpenes. It is found that all species of Heterotropa contain considerable amount of mono- and sesqui-terpenes in the oils.
Notizen: Physical Parameters and Possible Regulation of ζ-Aminolevulinic Acid Synthetase
Authors: Nandi Dhirendra L.
Published: August 2018

Physical measurements were made on the ζ-aminolevulinic acid synthetase from Rhodopseudomonassph eroides. These include a Stokes radius of 3.8 nm, determined by gel filtration, and sedimentation coefficient of 5.46 S by sucrose density gradient centrifugation. From these measurements and the value of partial specific volume of 0.732 ml/g deter­mined from the amino acid composition, the following physical constants were calculated: molecular weight, 88000; diffusion coefficient, 5.65 × 10-7 cm2 s-1 ; frictional ratio, 1.30; axial ratio, 5.0. The enzyme is inhibited by more than 50% by glyceraldehyde 3-phosphate (1 mᴍ) , pyruvate (0 .02 ᴍ) , α-ketoglutarate (0.02 ᴍ) , urea (0 .8 ᴍ) , CoCl2 (0.2 mᴍ) and hemin (5 µᴍ). The effect of these inhibitors on the possible regulation of this enzymic activity is discussed.
Stained Native Collagen: Interpretation of the Small Angle X-ray Scattering and Electron Microscopic Pictures in Terms of the Primary Structure
Authors: Meyer Helmut , Kilian Hanns-Georg
Published: August 2018

The average axial electron-density distribution of stained collagen fibers derived from X-ray small angle pattern, is shown to be substantially related to the projection of the polar amino acid residues onto the axis of the microfibril taking into consideration the staggering of neighbouring molecules. In order to arrive ultimately at a quantitative representation of the experimental data, an additional periodic fluctuation of the density in necessity of this regular microphase structure for an of collagen fibers will be indicated .
Acetylcholinesterase aus dem Gift von Bungarus multicinctus. Reinigung und Eigenschaften/The Acetylcholinesterase of Bungarus multicinctus Venom. Purification and Properties
Authors: Großmann H. , Weinert M. , Liefländer M.
Published: August 2018

Acetylcholinesterase from Banded krait (Bungarus multicinctus) venom has been purified by CM-Sephadex chromatography and affinity chromatography to a specific activity of 4290 U/mg. The purified enzyme is a glycoprotein. It is free of electrophoretically detectable contaminating proteins. A molecular weight of 140 000 ± 5 000 has been determined by gradient gel electrophoresis for the native enzyme. It is split into two equal-sized subunits (Mr 70 000 ± 2 000) by SDS treatment. The N-terminal amino acid analysis gave glycine and serine. The purified acetyl­ cholinesterase can be resolved by disc gel electrophoresis into four and by isoelectric focusing into six isozymes. The pI value of the main isozyme has been found to be 5.98 ± 0.05.
Assimilatory Nitrate Reductase of Rhodopseudomonas capsulata AD2: A Molybdo-Hemeprotein
Authors: Alef Kasem , Klemme Jobst-Heinrich
Published: August 2018

The assimilatory nitrate reductase of the phototrophic bacterium Rhodopseudomonas capsulata strain AD2 was purified to homogeneity by a combination of ammonium sulfate fractionation, chromatography on DEAE-cellulose and isoelectric focusing (isoelectric point of 4.8). The purified enzyme was active only with reduced viologen dyes or reduced flavin as electron donors. Contrary to other bacterial assimilatory nitrate reductases, the enzyme was not inhibited by chlorate, but rather accepted this substance as an alternate substrate. The molecular weight of the enzyme was 185 000 dalton as determined by gelfiltration. Subunit analysis by sodium dodecyl sulfate (SDS) gel electrophoresis yielded a single protein band with a molecular weight of 85 000 dalton, sug­gesting that the enzyme was composed of two identical subunits. The nitrate reductase contained 0.8 g-atoms molybdenum per 1.85 X 105 g protein and exhibited absorption maxima at 418, 523 and 552 nm in the reduced state (dithionite as reductant). The nitrate reductase of Rps. capsulata AD2 is the first prokaryotic enzyme of the assimilatory type that has been shown to contain heme.
Evidence for the Existence of meta and para Directing O-Methyltransferases in Tobacco Cell Cultures
Authors: Tsang Yun-Fuk , Ibrahim Ragai K.
Published: August 2018

The O-methyltransferase of tobacco cell culture was resolved to its meta and para directing forms by chromatography on DEAE-cellulose. Despite similarities in molecular weights and pi values of the two forms, however, evidence from pH optima, SH-group inhibitors, methylation ratios, SDS-acrylamide gels and mixed substrate experiments indicates the existence of two discrete enzymes acting at the meta and para positions of caffeic acid and quercetin, respectively; though the latter enzyme was less substrate specific than its meta counterpart.
Search for Millimeter Microwave Effects on Enzyme or Protein Functions
Authors: Tuengler P. , Keilmann F. , Genzel L.
Published: August 2018

Recent observations of nonthermal, resonant biological responses to weak millimeter microwave irradiation have led us to investigate whether similar influences exist on enzymatic functions in vitro. We chose (i) the reduction of ethanol in the presence of alcohol dehydrogenase and (ii) the cooperative binding of oxygen on hemoglobin. Using an irradiation intensity near 10 mW/cm2 the frequency was continuously varied from 40 to 115 GHz with a resolution of a few MHz. No micro­ wave influences were detectable within our experimental sensitivity of about 0.1% of the reaction rate in (i), or of the amount of bound oxygen at half saturation in (ii).
Characterization of an Endogenous Transcription Inhibitor from Physarum polycephalum
Authors: Hildebrandt Armin , Mengel Rudolf
Published: August 2018

A substance has been purified from isolated nuclei of Physarum polycephalum by equilibrium and velocity gradient centrifugations, ion exchange chromatography and gel filtration which has a high molecular weight, can be labeled in vivo with 32P, is heat stable and resistant to amylases, proteases, nucleases and phosphodiesterase but is sensitive to phosphatases or hydrolysis. This material consists of phospate and glycerol. It selectively inhibits in vitro transcription of RNA polymerases, predominantly the homologous enzyme A by binding to the enzyme. In the presence of this inhibitor of transcription a stable RNA polymerase-template complex cannot be formed. Binding to and inactivation of RNA polymerase is reversible at high ionic strength.
Die in vitro und in vivo Stabilität des Einschlusses von Methotrexat in negativ geladenen Liposomen nach Sterilfiltration/The in vitro and in vivo Stability of the Entrapment of Methotrexate in Negatively Charged Liposomes after Sterile Filtration
Authors: Freise J. , Magerstedt P. , Schmidt F. W.
Published: August 2018

The preparation of sterile artificial liposomes (phosphatidylcholine: cholesterol: dicethylphos-phate = 5:5:1) by Millipore® filtration is described. Conditions for storing liposome entrapped Methotrexate have been found which allow storage of the drug in the entrapped form over a period of at least 4 months. It is shown that intravenously injected liposome entrapped Metho­trexate is retained for at least 15 hours in the particulate form. During this time no free Methotrexate is detectable in the blood.
Accessibility of Extracellular Space in the Rhabdome of the Living Isolated Retina of the Crayfish
Authors: Schröder W. , Stieve H. , Classen-Linke I.
Published: August 2018

Diffusion of the tracer enzyme horseradish peroxidase (HRP) into the extracellular spaces of living isolated crayfish retinas was monitored by light-and electronmicroscopic identification of the reaction product obtained after immobilisation of the enzyme by fixation. During the incubation in enzyme containing saline (up to 3 hours) the extracellularly recorded electroretinogram (ERG) stayed normal and showed no substantial change. The reaction product of the enzyme HRP was found only extracellularly in the space between the microvilli in the rhabdome.

The results indicate an exchange of substances via extracellular pathways between the extra­ cellular side of the photosensory membrane and the bathing fluid in the living isolated crayfish retina.
Some Properties of the DCMU-Binding Site in Chloroplasts
Authors: Tischer Wolfgang , Strotmann Heinrich
Published: August 2018

Binding of the triazinone derivative metribuzin to thylakoid membranes was studied in depend­ence of temperature and trypsin pre-treatment of the chloroplasts. The temperature curve of the binding constant suggests that the lipid phase of the membrane contributes to inhibitor binding. Trypsin pre-treatment of the membranes removes the receptor sites for the inhibitor, while the trypsin effect on the affinity of the receptor to the inhibitor is marginal. Concomitantly trypsin treatment releases the inhibitory effect of metribuzin on the electron transport from DPC to DCPIP.
The Mode of Action of Photosystem II-Specific Inhibitors in Herbicide-Resistant Weed Biotypes
Authors: Pfister Klaus , Arntzen Charles J.
Published: August 2018

This report reviews studies which provide evidence defining the mode of action and site of action of photosystem II (PS II) herbicides; the involvement of the secondary electron carrier on the reducing side of PS II (called B) is indicated as the target site for these compounds. These studies of the action of PS II-inhibitors were performed in chloroplasts of various weed species in order to define the mechanism which is responsible for herbicide tolerance at the level of chloroplast membranes in newly discovered triazine-resistant weed biotypes. Many species of triazine-resistant weed biotypes have been collected in North America and Europe. Where data is available, these plants have been found to share the following common features:

a) they were discovered in areas where triazine herbicides had been used repeatedly,

b) resistance to the triazines is extreme; it is not due to a minor shift in herbicidal response,

c) no changes in herbicide uptake, translocation or metabolism - as compared to susceptible biotypes - can be detected,

d) resistance is selective for only certain classes of photosynthetic herbicides, and,

e) chloroplasts isolated from triazine-resistant weeds display high preferential resistance to the triazines in assays of photosystem II partial reactions.

To focus on the mechanism which regulates preferential herbicide activity, we have characterized susceptible and resistant chloroplasts in the presence and absence of herbicides. Properties of the PS II complex of chloroplasts from several different triazine-resistant weed biotypes share the following traits:

a) the herbicide binding site (as measured by direct binding of radiolabeled herbicides or by inhibition experiments) is modified such that the affinity for triazines is dramatically reduced.

b) alterations in response to many PS II-herbicides occur such that the triazine-resistant chloroplasts are very strongly resistant to all symmetrical triazines, strongly resistant to assymmetrical triazinones, partially resistant to pyridazones and uracils, only slightly resistant to ureas or amides, and increasingly susceptible to nitrophenols, phenols and the herbicide bentazon (all as compared to susceptible chloroplasts),

c) there is a change in the reaction kinetics of the electron transport step between the primary and secondary electron acceptors (referred to as Q and B ), and

d) in two examples, specific small changes in a membranepolypeptide can be detected in the resistant thylakoids.

We suggest that certain amino acids or segments of the apoprotein of B (the bound quinone which acts as the secondary electron carrier) are modified or deleted in these chloroplasts. Such a polypeptide change could affect both the redox poising of the Q-/B reaction pair, and the specific binding of herbicides.
Ethane Formation and Chlorophyll Bleaching in DCMU-Treated Euglena gracilis Cells and Isolated Spinach Chloroplast Lamellae
Authors: Elstner E. F. , Pils Irene
Published: August 2018

Light dependent chlorophyll bleaching and ethane formation in Euglena gracilis cells at slightly acidic pH values above 5.2 are enhanced by DCMU and other photosystem II blockers. Excited chlorophyll under conditions of limited energy dissipation seems to be the oxidant for ω-3 unsaturated fatty acids, yielding ethane and other (ethylene, “malondialdehyde”) oxidation products, cooxidizing chlorophyll.
Degradation and Metabolization of Lindane and Other Hexachloro- cyclohexane Isomers by Anaerobic and Aerobic Soil Microorganisms
Authors: Haider K.
Published: August 2018

Microbial Metabolization of Hexachlorocyclohexane, Anaerobic and Aerobic Microorganisms, Dechlorination of Hexachlorocyclohexane Microbial degradation of lindane or other hexachlorocyclohexane isomers has been observed to occur more rapidly in flooded than in upland soils. Experiments with a mixed bacterial flora enrich­ ed anaerobically from soils showed a rapid dechlorination and degradation of lindane. Screening studies with pure bacteria indicated that Clostridium spp. and several representatives of Bacillus spp. and Enterobacteriaceac effectively degraded lindane, while representatives of Lactobacillaceae and Propionibacterium were inactive. During degradation organic bound chlorine was released as chloride and nearly chlorine-free, partly volatile metabolites were formed. The chloride formation was promoted by the addition of glucose, pyruvate or formate.

Lindane was the most easily degraded isomer, while α-and especially β-and δ-hexachlorocyclo-hexane was also, but more slowly, dechlorinated. These isomers are relatively frequently observed as environmental contaminants, their occurrence might be caused by their greater persistence or / and by an isomerization of the γ-into α-and other isomers during microbial incubation as it was discussed by several authors. Experiments, however, whether or not this isomerization can be carried out by microbes, were negative or showed that it only can occur to a very minor extent.

Aerobic degradation of lindane proceeded only slowly and chiefly by formation of chlorinated aromatic compounds. One of the main intermediate metabolites seemed to be γ-pentachlorocyclo-hexene which was further transformed by the release of HCl or hydrogen and by addition of water. During anaerobic incubation, γ-tetrachlorocyclohexene intermediately occurred which was further dechlorinated to nearly chlorine-free compounds.
Inhibitory Effects of the Insecticides Allethrin, Lindane, and Jacutin-Fogetten Sublimate on Photosynthetic Electron Transport
Authors: Wild Aloysius
Published: August 2018

The inhibitory effects of the insecticides Allethrin, Lindane, and Jacutin-Fogetten sublimate on photosynthetic electron transport of broken chloroplasts were tested. 50 μmol l-1 Allethrin caused an inhibition of 80% of the benzoquinone and ferricyanide Hill-reactions. 39 μmol l-1 Lindane inhibited the basal, coupled and uncoupled electron transport to ferricyanide up to 35%. The precipitate formed by the sublimation of Jauctin-Fogetten containing Lindane depressed electron transport much more than pure Lindane. 50 μg ml-1 of the sublimate led to an 80% inhibition of ferricyanide Hill-reaction.
The Conformation of Bilin Chromophores in Biliproteins: Ramachandran-Type Calculations
Authors: Scheer Hugo , Formanek Helmut , Rüdiger Wolfhart
Published: August 2018

Ramachandran-type calculations are performed for conformations of bilin chromophores pres­ent in the biliproteins phycocyanin, phycoerythrin and phytochrome. The atomic coordinates are taken from x-ray data of crystalline model compounds, namely biliverdin for pyrrole rings B, C, D and substituted succinimides for the hydrogenated ring A including a thioether containing β-sub­stituent. Maxima and minima for steric hindrance are calculated for rotation of the thioether side chain, the rotation of pyrrole rings at single bonds (syn-anti-forms) and at double bonds (Z-E-isomers) of the methine bridges. Whereas quasi-planar structures are possible for all syn, Z-forms, only twisted structures are possible if anti, E-forms are considered. The relevance for the bilin con­formations of native biliproteins and of the Pr ⇌ Pfr phototransformation is discussed.
The Influence of Different Solvents on the Interaction between Metal Ions and Tetracycline
Authors: Schnarr Manfred , Matthies Michael , Lohmann Wolfgang
Published: August 2018

The interaction of the antibiotic tetracycline with a few metal ions, esp. Cu(II), in different so l­ vents has been investigated by means of IR, ESR, and UV /VIS spectroscopy. It could be shown that the site of complexation depends on the solvent used. In DMSO the interaction occurs mainly via the A ring. In water (pH = 5.7) and octanol, the A chromophore as well as the BCD entity of the molecule are involved in complexation. If the tetracycline concentration exceeds the Cu(II) concentration, a 2 : 1 (antibiotic : Cu(II)) complex seems to be formed, at least in DMSO.
Catalytic Subunit of Adenosine Cyclic 3',5' Monophosphate- Dependent Protein Kinase from Rat Muscle: Basic Properties and Factors Influencing the Activity
Authors: Pyerin Walter , Gagelmann Michael , Kübler Dieter , Kinzel Volker
Published: August 2018

The catalytic (C) subunit of isoenzyme II of cyclic AMP-dependent protein kinase from rat muscle, purified to apparent homogeneity, was investigated for some of its basic properties and factors that influence its activity. The properties were found to resemble those of C subunits of both isoenzymes I and II from various other tissues of different species. This concerns the molecular weight estimate (about 37 k), ultraviolet light absorption spectrum, isoelectric point (pH 9.0 ± 0.2), the apparent KM values for histone and protamine (for both substrates ≤ 10 μᴍ) and the apparent KM for cosubstrate ATP (3-4 μᴍ). The enzyme is sensitive to the heat- stable inhibitory protein.

The enzyme activity is stable up to 40 °C but becomes destroyed at higher temperatures; the half life at 50 °C is slightly less than 1 min, and at ≥ 60 °C activity is nullified within 1 min. Activity is lost on freezing and thawing. Substrate histone does not improve temperature stability; cosubstrate ATP in absence of Mg2+ decreases, but in presence of Mg2+ increases stability. The optimum pH of enzyme activity is at pH 6.8 for histone and pH 7.8 for protamine phosphoryla­tion. The enzyme becomes irreversibly inactivated at pH values below 5. For activity, the enzyme has absolute requirement for a divalent metal ion, highest activity is found in presence of Mg2+ or Co2+; the optima are at 5-10 mᴍ (half maximum at 0.9 mᴍ) and 0.5-0.8 mᴍ (half maximum at 0.25 mᴍ) for Mg2+ and Co2+, respectively. None of the various other metal ions tested were nearly as effective as these two. Ca2+ antagonized Mg2+. A considerable effect on activity by ionic strength was observed. In dependence on the substrate used, activity is influenced strongly by some anions and zwitterions. E. g. in presence of acetate, histone phosphorylation is by a factor of 3-4 higher than in presence of sulfate, whereas protamine phosphorylation is only half that in presence of sulfate. Roughly the following order of enzyme activity in presence of the respective buffer system was found: MOPS (100%) ≥ TES (95%) ≅ HEPES > MES (65%) ≅ acetate ⪢ ADA (20%) > phosphate (15%) > TRIS • maleate (7%).
Evidence for the Existence of Two β-Carotene Pools and Two Biosynthetic β-Carotene Pathways in the Chloroplast
Authors: Grumbach K. H.
Published: August 2018

Two β-Carotene pools were obtained in the chloroplast. It is concluded that one pool is very small like α-carotene and responsible exclusively for the biosynthesis of β-ionone-xanthophylls. The other β-carotene pool is proposed to be the one, that is located close to photosystem I and is involved in photosynthesis as a light protecting agent for chlorophylls against photo-oxidation. Furthermore evidence is given that both β-carotene pools are synthesized by independent biosyn thetic pathways.
Photosensibilisierung isolierter Mesophyllzellen von Calystegia sepium L. / Photosensibilization of Isolated Mesophyll Cells of Calystegia sepium L.
Authors: Ries P. , Beiderbeck R.
Published: August 2018

Cell division of isolated mesophyll cells of Calystegia sepium can be made sensitive to long-wave UV (LUV) by treatment with 8-methoxypsoralen (8-MP). The inhibition of cell division de­ pends on 8-MP concentration and the length of light exposure. Only the simultaneous presence of 8-MP and LUV gives effective photosensibilization. Cells treated with 8-MP in the dark can be made non-sensitive to LUV by washing out the furocoumarin prior to irradiation. The furocoumarins may offer a means of cell selection.
Inhibition of Photosynthetic Electron Transport in Tobacco Chloroplasts and Thylakoids of the Blue Green Alga Oscillatoria chalybea by an Antiserum to Synthetic Zeaxanthin
Authors: Lehmann-Kirk Ursula , Bader Klaus P. , Schmid Georg H. , Radunz Alfons
Published: August 2018

An antiserum to synthetic Zeaxanthin inhibits photosynthetic electron transport on the oxygen-evolving side of photosystem II in tobacco chloroplasts and thylakoids of the filamentous blue-green alga Oscillatoria chalybea. The inhibition site lies for both species between the site of electron donation of water or tetramethyl benzidine and that of diphenyl carbazide or manganese II ions. Typical photosystem I reactions are not impaired by the antiserum. The effect of the antiserum concerning the inhibition site is practically identical to that of the earlier described antiserum to violaxanthin. However, the degree of inhibition seems to be generally somewhat lower with the antiserum to Zeaxanthin, than with that to violaxanthin which hints at a lesser accessibility of zeaxanthin, in the tylakoid membrane in comparison to violaxanthin.

In the course of these investigations new evidence was obtained that the oxygen-evolving side of the electron transport scheme is differently organized in Oscillatoria chalybea when compared to tobacco chloroplasts. Thus, the silicomolybdate reduction with water as the electron donor is sen­sitive to DCMU in these algae.
An in vitro Culture System for Crayfish Organs
Authors: Daig Konrad , Spindler Klaus-Dieter
Published: August 2018

Organs of crayfishes - mainly integument of Astacus leptodactylus - have been kept in an in vitro culture for several days. The medium consists of 2 parts of van Harreveld saline and one part of horse serum, supplemented with antibiotics for long term cultures. This medium is very similar to the Astacus hemolymph in its ionic content, the pH, the osmolarity, the protein concentration and the cholesterol content. The glucose concentration is somewhat higher and there are differences in the nitrogen excretory end products. Integument of Astacus is able to synthesize protein, RNA and DNA in vitro for several days. Ecdysone is converted to 20-OH-ecdysone by the integument under in vitro conditions.
On the Role of Light in the Mating Behavior of Drosophila subobscura
Authors: Pinsker Wilhelm , Doschek Elfriede
Published: August 2018

Unlike other related species wild flies of Drosophila subobscura require light for successful ma­ting. Two explanations for the influence of light on the reproductive behavior could be suggested:

1)Light increases sexual activity.

2)Light mediates the transmission of visual courtship elements.

In order to decide this question the mating success of wild-type and mutant flies was tested at light of different wave-lengths. It turned out that mutant flies with reduced ommochrome compo­nent of the eye pigment were not able to copulate at wave-lengths above 570 nm whereas the other strains still copulated at wave lengths close to the limit of their spectral sensitivity. Since spectral sensitivity of the photoreceptors is assumed to be the same in all strains tested the difference in mating success must be ascribed to effects caused by the lack of pigment. Thus an investigation of the optomotor response was carried out. It revealed that mating success is clearly correlated with the ability to discriminate contrast. From this result it can be concluded that the exchange of visual signals and not merely the perception of light is essential for the courtship of Drosophila subobscura. Optical stimuli may be important at two different stages of mating behavior: at the begin­ning, when the male is activated by the sight of a female, and during the wing dance, where the movements of the partners are coordinated optically.
The Role of 5-Hydroxymarmesin in the Bioge­nesis of Bergapten
Authors: Dall’Acqua F. , Innocenti G. , Caporale G. , Rodighiero P. , Guiotto A.
Published: August 2018

5-hydroxymarmesin administered to leaves of Ficus carica and to cut ends of Ruta graveolens has been efficaciously and selectively converted into bergapten while no radioactivity was observed in the other isolated furocoumarins.
On the Pigmentation of the Pollen of Nothofagus antarctica (Forst.) Oerst. (Fagaceae)
Authors: Wollenweber Eckhard , Wiermann Rolf
Published: August 2018

Abstract Extraction of pollen of Nothofagus antarctica with acid hydrolysis yields kaempferol, quercetin, the rare flavonol sexangularetin, and naringenin. The tetrahydroxy-chalcone isosalipurpol is shown for the first time to occur in such high amount as free aglycone in mature pollen; it yields naringenin in usual extraction procedures. The bright yellow coloration of the pollen is due to the presence of isosalipurpol and sexangularetin.
Strukturuntersuchung mit Röntgenbeugungsmethoden an Lipopolysacchariden von Salmonella minnesota Mutanten S SF 1111 und R 595 SF 1167
Authors: Wawra H. , Buschmann H. , Formanek H. , Formanek S.
Published: August 2018

The lipolysaccharides of two mutants of Salmonella minnesota with known chemical structure were investigated by X-ray methods. Both thickness of the lipopolysaccharide layer and arrangement of the molecular components could be estimated. Using these informations a space-filling model of the structure was built.
On the Dynamic Model of tR N A : Recent Experimental Findings
Authors: Gurel Okan
Published: August 2018

Recent experimental findings are shown to support various aspects of the dynamic model of tRNA proposed earlier and the interaction between tRNA, mRNA and the ribosomal RNA’s. Extra loop of tRNA molecule is suggested to play a role in recognizing the corresponding amino acids and a correlation is presented between the tRNA molecules and the corresponding amino acids as tabulated by the genetic tableau.
Sequences Homologous to BAV Component of HL23V in Baboon Tissues
Authors: Mishra L. , Baluda M. A.
Published: August 2018

The BAV component of HL23V virus (HL23V-BAB) hybridized to DNA from different Baboon tissues and appears to be an endogenous Baboon virus. Competition hybridization studies show that HL23V-BAB is closely related to viruses isolated from various Baboon species: P. hamadrys, P. papio, and P. cynocephalus. Competition hybridization studies also show that normal Baboon tissues contain more copies of proviral DNA than cells infected in vitro.
Notizen: Absence of Microsomal Lipid Peroxidation in Acatalasemic Mice
Authors: Steffen Christian
Published: August 2018

Catalase (E. C. 1.11.1.6) activity and NADPH-depen-dent lipid peroxidation have been measured in liver micro­ somes from normal and acatalasemic mice. The absence of lipid peroxidation in acatalatic microsomes is not restituted by exogenous catalase as is microsomal methanol oxidation nor is it inhibited by sodium azide, thus suggesting an additional abnormality in these mice.
Notizen: A New Mutant Affecting Aldehyde Oxidase in Drosophila melanogaster
Authors: Bentley Michael M. , Williamson John H.
Published: August 2018

A new locus, Aldox-2, which affects the activity and heat stability of aldehyde oxidase in D. melanogaster is described. The Aldox-2 locus is localized to map position 86 on chromosome 2, between c and px. Aldehyde oxidase activity in Aldox-2 homozygotes is approximately 25 - 30% that of the Oregon-R wild-type control strain. The enzyme from the mutant stock is much more heat labile than is the enzyme from the wild-type strain. Both the activity and heat phenotypes are completely recessive.
Notizen: Der Mäuse-Inzuchtstamm STU. Entwicklung und Eigenschaften
Authors: Schäfer W.
Published: August 2018

The highly inbred STU mouse strain (up to 100 inbred generations) was developed from a German white mouse colony. Its properties are described with special emphasis on the occurrence of tumors, occurrence of C-type oncornaviruses and on its immunological reactivity. The predominant tumor is a fibrosarcoma (~23% incidence).
Untersuchungen zum Biosyntheseort und Transport von Cardenoliden in Convallaria majalis L. / Cardenolide Biogenesis and Translocation in Convallaria majalis L.
Authors: Kopp Brigitte , Löffelhardt Wolfgang , Kubelka Wolfgang
Published: August 2018

[4-14C] Progesterone, fed to leaves and whole plants of Convallaria majalis L., was incorporated into the main cardenolide glycosides. After application of [4-14C] progesterone to the leaves of intact plants via the epidermis labelled desglucocheirotoxin, convallatoxin and convallatoxol were isolated from rhizomes and roots. When the precursor was administered to rhizome cuttings no radioactivity could be detected in the cardiac glycoside fraction. The experiments pointed out that during the stage of flowering biosynthesis of cardenolide glycosides takes place in the leaves of Convallaria majalis rather than in the subterranean parts of the plant. A translocation of these substances from the leaves to rhizomes and roots seems possible.
Effect of Mechanical Traumatization on Rate and Constancy of Oxygen Uptake of Isolated Diaphragms
Authors: Schmidt H. J. , Sommer M. , Pichotka J.
Published: August 2018

Diaphragms of mice were traumatized by division parallel or transversally to the muscle fibres. The extent of traumatization was varied by the degree of subdivision. Oxygen uptake was measured by the Warburg technique. Undivided diaphragms as control displayed constant oxygen uptake for the four hours of observation. With divided diaphragms oxygen uptake was unstable. Division parallel to the muscle fibres resulted in continuous decrease of oxygen uptake after a normal initial phase; the decline was significantly steeper with increasing extent of traumatization. Division transversally to the muscle fibres resulted in an initial increase of oxygen uptake followed in a second phase by a continuous decrease. The initial increase as well as the final decrease of oxygen uptake was more pronounced with higher extent of subdivision.
Evidence for a Rapid Oxygen-Uptake in Tobacco Chloroplasts
Authors: Schmid Georg H. , Thibault Pierre
Published: August 2018

A fast oxygen uptake, induced by a sequence of short (5 µsec) saturating flashes was observed in chloroplasts of wild type tobacco and two chlorophyll-deficient tobacco mutants. One of the chlorophyll mutants is the earlier described variegated tobacco NC 95. Chloroplasts of this mutant exhibit only photosystem I mediated photoreactions, hence the observed oxygen uptake is to be associated with photosystem I. This is further substantiated by the fact that the oxygen uptake is insensitive to DCMU in the two chloroplast types used, which have both photosystems fully functioning. The uptake depends on the addition of electron acceptors like p-benzoquinone in intact chloroplasts or on p-benzoquinone or ferricyanide in chloroplasts that have lost the envelope. In dark adapted chloroplasts, therefore, under these conditions the overall apparent gas exchange in the first two flashes is consumption. Although the uptake is slower than photosynthetic oxygen evolution it clearly affects the oxygen yield in the flash sequences. This is demonstrated by several experiments in which the apparent oxygen consumption in the absence of DCMU oscillates with a periodicity of four. We have indications that in chloroplasts of the tobacco aurea mutant Su/su the oxygen uptake is faster than in wild type chloroplasts.
Die Sequenzkomplexität transkribierter unique DNA Sequenzen im Genom von Maus P815 Mastocytoma Zellen / Sequence Complexity of Transcribed Unique DNA Sequences in Genome of Mouse P815 Mastocytoma Cells
Authors: Boehm Thomas L. J. , Drahovsky Dusan
Published: August 2018

The sequence complexity of nuclear RNA from mouse liver, mouse spleen and highly malignant P815 mastocytoma was measured by nRNA driven hybridization to unique DNA sequences of P815 cells. The unique DNA sequences represent 63% of the total nuclear DNA of P815 cells and their availibility in hybridization experiments was found to be 76%. Of these sequences 7.8% formed hybrids with nuclear RNA of this cell, about 11.5% with mouse spleen and about 14.5% with mouse liver nuclear RNA. Assuming an asymmetrical transcription, the complexities of these transcripts are 2.8 × 108 nucleotides for mouse P815 mastocytoma, 4.3 × 108 for mouse spleen and about 5.3 × 108 nucleotides for mouse liver.

Cellular specifity of the transcribed information was analyzed in additivity experiments, in which unique DNA sequences, not complementary to the nuclear RNA of one cell were annealed to the nuclear RNAs of the two other tissues/cells. In these experiments most of the nuclear RNA se­ quences of P815 cells were found to be also present in the nucleus of mouse liver and spleen. Only a small portion of the unique DNA sequences of P815 mastocytoma (about 1.2% corresponding to 4.4 ×107 nucleotides) was found to be complementary only to P815 mastocytoma nuclear RNA.
The Physiological Optics of a Nocturnal Semi-Aquatic Spider, Dolomedes aquaticus (Pisauridae)
Authors: Williams David S.
Published: August 2018

The optics of the posterior eyes of the amphibious spider, Dolomedes aquaticus, are described. The lenses have strongly-curved spherical front and rear surfaces, and therefore, a fairly high light capturing ability - they have F-numbers of 0.9 - yet, the large amount of spherical aberration predicted by their shape is mostly corrected. The receptive segments of the receptors are arranged in rows, each row separated by pigmented glial cells, but within a row, rhabdomeres from neigh­ bouring cells are contiguous so that coupling between cells from the same row seems a possible way of increasing absolute sensitivity for night vision. When the spider submerges, an air-layer is held over the comeal surfaces - as with a diver’s face mask - so that light is focused on to the receptive layer of the retina under water as well as above. These features are considered as adaptations for the nocturnal and semi-aquatic habits of the spider.
Eine fluorometrische Bestimmungsmethode für mikrosomale Monooxygenase-Aktivität der Rattenleber mit Scoparon als Substrat / A Fluorometric Test for Microsomal Monooxygenase Activity in the Rat Liver with Scoparone as Substrate
Authors: Müller-Enoch Dieter , Thomas Helmut , Ockenfels Heinrich
Published: August 2018

A sensitive fluorometric test for the determination of monooxygenase activity in liver microsomes from rats is described. The assay is based on the O -demethylation of 6,7-dimethoxycoumarin (scoparone) to 7-hydroxy-6-methoxy-coumarin and 6-hydroxy-7-methoxycoumarin. Pretreatment of rats with phenobarbital or polycyclic hydrocarbons (benzo[a]pyrene, 3-methylcholanthrene) causes a significant increase in the amount of microsomal dealkylation activity.
Characterization of a Light-Induced Oxygen-Uptake in Tobacco Protoplasts
Authors: Schmid Georg H. , Thibault Pierre
Published: August 2018

Protoplasts prepared from the wild type tobacco N. tabacum var. John William’s Broadleaf exhibit photosynthetic oxygen-evolution if the suspension medium is supplemented with bicarbonate. In the absence of bicarbonate no steady state oxygen-evolution is observed with such preparations. Instead, an appreciable uptake which is mainly insensitive to DCMU and which persists over hours, and therefore is no induction phenomenon, is seen. Protoplasts of the tobacco aurea mutant Su/su, which is a plant with an exceptionally high photorespiration, show an oxygen consumption in the light which is 4 to 5 times higher per protoplast than in the wild type. Again, the uptake is practically insensitive to DCMU which means that the effect is to be associated with photosystem I. This is further substantiated by the fact that protoplasts prepared from yellow leaf1 sec­tions of the variegated tobacco mutant NC 95 also show the light induced uptake. As reported earlier, the yellow leaf sections of this mutant exhibit only photosystem I reactions.

The action spectrum for this oxygen-uptake yields the spectrum of chlorophyll. Consequently, this uptake is an inherent property of the chloroplast and has nothing to do with earlier described, light-dependent oxygen consumptions, which were mainly driven by blue light and hence used some yellow pigment as the photoreceptor. No effect or contribution of yellow pigments such as carotenoids is seen since the action spectrum with the yellow tobacco mutants which have an up to 4 fold higher carotenoid/chlorophyll ratio than the wild type is identical to that of the wild type.
Biologische Wirkungen elektromagnetischer Felder / Biological Effects of Electromagnetic Fields
Authors: Bernhardt J.
Published: August 2018

This résumé deals with thermal and nonthermal effects of electromagnetic fields on man. In consideration of two aspects a limitation is necessary. Firstly, there will be discussed only direct and immediate influences on biological cells and tissues, secondly, the treatment is limited to such phenomena, for which biophysical aproximations, based on experimental data, could be developed.

Hazards for the human being may occur only by thermal effects within the microwave range. Regarding frequencies below approximately 30 kHz, excitation processes cannot be excluded in exceptional cases. Thermal effects are predominant, between 30 kHz and 100 kHz, before excitations can appear.

Furthermore, by comparing the electrically and magnetically induced currents with the naturally flowing currents in man caused by the brain’s and heart’s electrical activity, a “lower boundary-line” was estimated. Regarding electric or magnetic field strengths undercutting this boundary-line, direct effects on the central nervous system may be excluded; other mechanisms should be responsible for demonstrated biological effects. The paper closes referring to some reports - presently discussed - on experimental findings of biological effects, which were observed as a result of the influence of electromagnetic fields of small field strengths.
Enrichment of Solanum khasianum Callus Generating Rootlets with Steroidal Glycoalkaloids
Authors: Kokate Chandra K. , Radwan Samir S.
Published: August 2018

Undifferentiated callus cultures of Solanum khasianum contain only traces of steroidal glycoalkaloids, whereas cultures which have just started to generate rootlets contain these com pounds at a level of up to 5.2% of the dry weight. Only 0.34% steroidal glycoalkaloids occur in the seeds; they consist predominantly of solasonine and solanidine as well as traces of an unidentified com pound. Conversely, steroidal glycoalkaloids from tissue cultures starting organogenesis contain the unidentified com pound as a major fraction, in addition to small amounts of solasonine and solanidine.
Algal Ferredoxin-NADP+ Reductase with Different Molecular-Weight Forms
Authors: Bookjans Gerhard , Böger Peter
Published: August 2018

Ferredoxin-NADP+ reductase from the microalga Bumilleriopsis was isolated by a combination of affinity chromatography on a flavodoxin-Sepharose 4 B column and usual purification procedures. Both the elution pattern of the final gel filtration step and of the sodium dodecylsulfate (SDS) disc gel electrophoresis indicate that there are at least two different molecular-weight forms of the reductase, a monomeric form and a dimeric one.
Suppression of Experimental Allergic Neuritis with P2 Protein of PNS Myelin
Authors: McDermott J. R. , Keith A. B.
Published: August 2018

Experimental allergic neuritis was induced in the guinea pig with bovine PNS myelin. Treatment with P2 protein at the onset of the disease markedly reduced the severity of the clinical signs compared with untreated controls and an­imals treated with CNS myelin basic protein. The mortality was reduced from 94% in the combined control group to 50% in the treated group. Saline was a better vehicle for ad­ministration of the suppressive inoculation than incomplete Freund’s adjuvant.
Nondestructive Determination of Protein Content of Viable Seeds by Proton Enhanced 13C NMR
Authors: Rutar V. , Blinc R. , Stefan J.
Published: August 2018

13C, NMR, Protein Content, Seeds Proton enhanced 13C NMR spectroscopy was used for a non-destructive determination of the protein content in single viable soybean, horse-bean, bean and com seeds. The intense 13C oil lines were suppressed by a series of saturating pulses and spin temperature reversal so that only the 13C protein and carbohydrate signals of the solid part of the seed were detected. Significant seed to seed variations in the protein content were found which can be used as a basis for rapid seed selection in plant breeding programs.
Determination of Progesterone in Vegetative Organs and Cell Organelles of ConvaUaria majalis L. by Radioimmunoassay
Authors: Kopp B. , Löffelhardt W.
Published: August 2018

Progesterone was extracted from leaves and subterranean parts of Convallaria majalis L. and quantified by radioimmunoassay. During the stage of flowering the content of progesterone in rhizomes was by a factor of four higher than in leaves and by a factor of ten higher than in roots, whereas five weeks later the level of progesterone was unchanged in rhizomes and roots but was elevated in the leaves. The change in progesterone distribution is discussed in relation to the development of the plants. At the subcellular level the mitochondrial and microsomal fractions contained the largest quantity of progesterone in leaf cells. However, significant amounts were also found in the 2000 × g fraction com prising nuclei and chloroplasts.
P1, P3-(5′-Guanosyl-5″-[14C]adenosyl) triphosphat: Darstellung der Kappenmutterverbindung sowie deren Abbauverhalten gegenüber subzellulären Fraktionen der Rattenleberzelle / P1, P3-(5′-Guanosyl-5″-[14C] adenosyl) triphosphate: Preparation of the Cap Parent Compound and Its Catabolic Properties towards Rat Liver Subcellular Fractions
Authors: Bomemann Siegmar , Schlimme Eckhard
Published: August 2018

We report on the chemical preparation of 14C-labeled P1, P3-(5′-guanosyl-5″-adenosyl) triphosphate (1) which is the parent compound of 5′-terminal cap structures of most eukaryotic mRNAs.

Incubation experiments of cap (1)- and non cap-structured nucleotides as Ap2A (2) as well as their ribose ring opened derivatives (3, 4) with rat liver subcellular fractions show that capdegrading nucleases being able to unblock 5′ termini are present in nuclei but not in mitochondria.