bluuebunny/crossref_metadata_2025 huggingface dataset:
Zur Frage der Bildung von Dimethylnitrosamin aus Tetracyclin-Derivaten bei der Nitrosierung in saurer Lösung / On the Problem of Dim ethylnitrosamine Form ation from Tetracycline-Derivatives by Nitrosation Reaction in Acidic Medium
Authors: Röper Harald , Heyns Kurt
Published: August 2018

The hydrochlorides from tetracycline and six tetracycline derivatives *-7-dimethylamino-6-des-methyl-6-desoxytetracycline [minocycline], 7-chlorotetracycline [chlorotetracycline], 7-chloro-anhy-drotetracycline [anhydrochlorotetracycline, 7-chloro-6-desmethyltetracycline [demethylchlorotetra- cycline], 5-hydroxytetracycline [oxytetracycline] and 6-desoxy-5-hydroxytetracycline [doxycycline] - were reacted with different amounts of sodium nitrite at 37 °C for two hours in aqueous buffer solutions at pH 2 and 4.

Dimethylnitrosamine formation was confirmed by gas-liquid chromatography and by combined gas-liquid chromatography/mass-spectrometry from minocycline, doxycycline, oxytetracycline and an- hydrochlorotetracycline.

Dimethylnitrosamine formation from minocycline and doxycycline was blocked by ascorbic acid. The catalytic effect of sodium thiocyanate for the dimethylnitrosamine formation from minocycline and nitrite was investigated.

The different reactivity of the investigated tetracycline derivatives towards nitrite in acidic solutions is discussed by stereochemical considerations in connection with the formation of hydrogen bridge linkages. This hypothesis was confirmed by dimethylnitrosamine formation from anhydro-chlorotetracycline and sodium nitrite at pH 2.
Untersuchungen von Sedimentkernen des Bodensees I. Profile der polycyclischen aromatischen Kohlenwasserstoffe / Investigation on Drilling Cores of Sediments of Lake Constance I. Profiles of the Polycyclic Aromatic Hydrocarbons
Authors: Grimmer Gernot , Böhnke Heinz
Published: August 2018

The content of polycyclic aromatic hydrocarbons (PAH) from sediment layers of Bodensee areas differently exposed to environmental burden were determined. 32 PAH and 10 nitrogen containing PAH were identified by comparison with authentic samples.

A method of quantitativ enrichment and gasdiromatographic determination of PAH containing 4-7 rings is described. In a comparative profile analysis only 20 most abundant PAH have been regarded.

Low burdened areas (entre of the lake, 250m deep; Güttingen) show only 10 - 20% of the PAH content of high-burdened areas (mouth of Argen and Schüssen).

The qualitative and quantitative composition of the PAH fraction (PAH-profile) from different layers of a sediment drilling core are very similar whereas profiles from different regions can be distinguished.

The concentration of PAH increases from the surface to a layer with maximum burden (1965 - 1970) and then decreases to a remaining concentration (1900). From the typical PAH profile and some characteristic compounds as e.g. benzo (b) -naphtho (2,1-d) thiophan, benz (a/c) acridines, benzo (a/b/c)-carbazoles, dibenzacridines, and dibenzcarbazoles some potential sources as motor- car traffic, petroleum, fuel oil, and used lubricating oil can be excluded. Coal combustion smoke gas is supposed to be the main source of emission.
Electrophoretic Analyses of the Crop Contents of Helobdella stagnalis (L.) (Hirudinea)
Authors: Keim Albert
Published: August 2018

Electrophoretic Pattern, Crop Contents, Identification of Prey Species First, experiments were tested for a new method concerning analyses of crop contents in liquo-somatophagous animals. Disc-electrophoretic separations of the crop contents of Helobdella stagnalis yielded protein patterns typical for the number of bands and for the relative mobilities in these Chironomid larvae, on which H. stagnalis were fed. Additionally, slowly migrating bands occurred in the separations of the crop contents, varying in their number; likewise, an esterase showed a high activity at a crop contents of pH 6.2.
The H+/e Ratio in Chloroplasts is 2. Possible Errors in its Determination
Authors: Saphon Satham , Crofts Antony R.
Published: August 2018

Chloroplasts H+/e Ratio, Buffering Capacities The number of H+ released inside the chloroplast thylakoids per electron flowing to the terminal electron acceptor (the H+/e ratio) has been investigated using a pH indicator dye technique. The apparent H+/e ratio was measured by comparing the absorbance change due to H+-uptake outside the thylakoids in the absence of uncoupling agent, and the absorbance change due to the net H+-production associated with water-splitting after addition of uncoupling agent in the presence of ferricyanide.

(1) The apparent H+/e ratio was found to be higher than 2, using methylamine as uncoupling agent (> 1 mм). It varied with the concentrations of added buffer.

(2) The apparent H+/e ratio obtained with methylamine as uncoupling agent (with or without additional buffer) approached the value of 2 with decreasing concentrations of methylamine.

(3) A consistent H+/e ratio of 2 was also obtained with gramicidin or the nigericin-type ionophore dianemycin over a relatively large concentration range, and did not vary with addition of extra buffer.

(4) The buffering capacity of the chloroplast suspension was estimated and was found to be the same order of magnitude as that of methylamine at the concentrations used.

We suggest that the high H+/e ratios reported 423, 510-523 [1976]) reflect a failure to take account of the change in buffering capacity of the chloroplast suspension on adding uncoupling concentrations of methyl­ amine. Other possible sources of error in the estimation of H+/e ratio by different techniques are also discussed.
Thymineless Death in Escherichia coli
Authors: Samanta Himadri K. , Bhattacharjee Sukhendu B.
Published: August 2018

Bacteria, Thymine Starvation, Recovery, Filamentformers For filament forming strains of Escherichia coli, it is shown that susceptibility to thymine starvation was dependent upon the nature of the plating media. In such bacteria, p art of the induced damages was found to be repairable if the cells after starvation were held in a non-nutrient medium. For non-filament forming bacteria, no such phenomena were observed.
The Tautomeric Conformers for the Molecules of Guanine and Cytosine. Some Rem arks about Their Stability
Authors: Marañon Julio , Sorarrain Oscar M.
Published: August 2018

In this paper we seek to determine the shape of the barrier between the normal and tautomeric conformers for some excited singlet and triplet states in the molecules of guanine and cytosine. The molecules are considered isolated and a particular movement of the H atom is analysed.

The semi-empirical CNDO/2-CI has been used. The calculated results are compared with the available experimental data.
Schwermetalle in Höheren Pilzen, III * Vanadium und Molybdän / Heavy Metals in Higher Fungi, II I. Vanadium and Molybdenum
Authors: Meisch Hans-Ulrich , Schmitt Johannes A. , Reinle Wolfgang
Published: August 2018

In several series of 212 samples, higher fungi, especially from the genus Amanita and related genera, were analyzed by atomic absorption spectroscopy on their content of the trace metals vanadium and molybdenum. Only vanadium was found to be present in high concentration in the fly agaric mushroom (Amanita muscaria), while 22 of its related species showed the normal V-content of the higher fungi tested. A correlation with the presence of molybdenum could not be detected. A special enrichment of Mo was not found in higher fungi. The analysis of several fruit bodies from A. muscaria showed that the highest V-content was present in the bulb and in the lamellae, both contents increasing with age, while the spores contained only 1 - 2% of the lamellar vanadium.
Glycerol Conformation and the Crystal Structure of Lipids II. A Further Study of Tripalmitin and Conformationally Fixed Analogs by Small-Angle X-Ray Diffraction and Reflection Electron Diffraction
Authors: Dorset Douglas L. , Pangborn Walter A. , Hancock Anthony J. , van Soest Ton C. , Greenwald S. M.
Published: August 2018

The utility of analogs to glycerol-containing lipids based on the configurational isomers of cyclo-pentane-1,2,3-triol for ab initio crystal structure analysis via electron diffraction is assessed further. Such analogs of tripalmitin are examined with the natural triglyceride via low angle X-ray diffraction. The 1,3/2 (all-trans) and 1,2/3 (cis-trans) analogs give long spacing dimensions some 23 Å greater than found for the β-2 form of the natural compound, consistent with the long spacing observed for a β-3 form. The 1,2,3/0 (all-cis) analog gives a long spacing near that of the a-form of the triglyceride. Reflection electron diffraction measurements on the 1,3/2 and 1,2/3 analogs reveal a chain tilt near 60° for both and untilted chains for 1,2,3/0. A more accurate tilt determination from X-ray long spacings of the homologous series of 1,3/2 pseudotrilaurin to 1,3/2 pseudo-tripalmitin confirm the 67° tilt expected for the β-3 form. Therefore, given the same T,, methylene subcell, the molecular packing is very close to natural triglycerides. The subtle influences of the cyclopentane ring are overcome for 1,3/2 analogs based on stearic and arachidic acids. This emphasizes the utility of these structural analogs for ab initio crystal structure determinations of glycerol containing lipids.
Enzymatic Determination of the Anomeric Structures of Two Blood-Group B Active Glycosphingolipids Recombined with Apolipoproteins
Authors: Hanfland Peter , Assmann Gerd , Egge Heinz
Published: August 2018

Anomeric configuration of oligosaccharides usually is established by specific glycosidases. For this purpose detergents achieving water solubility of primarily insoluble glycosphingolipids as substrates have been replaced by delipidated hum an serum high density lipoproteins. The new method, tested by several well characterized glycosphingolipids and glycosidases, finally was applied to the evaluation of anomeric structures of two blood-group B active glycosphingolipids [ceramide hexa-saccharide (B-I) and ceramide octasaccharide (B -II)] from hum an erythrocyte membranes. In both B-I and B-II, α-glycosidic linkage was dem onstrated for the term inal galactose and fucose residues. β-glycosidic linkage has been evaluated for backbone saccharides. Together with the results pre­ viously obtained by composition analysis, linkage analysis and sequence analysis the following complete structure can be established:

B -I: Galα1 → 3Gal (2 ← 1αFuc)β1 → 4GlcNAcβ1 → 3Galβ1 → 4Glcβ1 → 1Cer;

B-II: Galα1 → 3Gal (2 ← 1αFuc)β1 → 4GlcNAcβ1 → 3Galβ1 → 4GlcNAcβ1 → 3Galβ1 → 4Glcβ1 → 1Cer.
Psoralen Photosensitization of L 1210 Leukaemia Cells: an Approach to a New Combined Therapy
Authors: Carlassare F. , Baccichetti F. , Bordin F. , Anselmo L.
Published: August 2018

Psoralen photosensitization of L 1210 cells has a strong effect on DNA and RNA syntheses and this result appears connected with the psoralen photobinding to DNA. Protein synthesis is less sensitive and its inhibition seems due to a different photochemical interaction, very likely to the psoralen photobinding to RNA. A combined therapy using cyclophosphamide and L 1210 cells psoralen-photoinactivated was perform ed after the leukaem ia transplant, showing a significant decrease in mortality, even in comparison with the simple treatment with the alkilating drug.
Mg2+-H+ Exchange in Chloroplast Membranes in Dark
Authors: Bose Salil , Hoch George E.
Published: August 2018

Protons are released from unilluminated chloroplasts after the addition of Mg2+. The greatest number of protons was measured at pH 6.5 and corresponded to 0.6 mol protons per mol chlorophyll.
9-Aminoacridine Binding to Chloroplast Membranes in Dark. Reversal by Mg2+
Authors: Bose Salil , Hodi George E.
Published: August 2018

9-Aminoacridine (9AA) binds to photosynthetic m em branes of unilluminated chloroplasts in low-salt media. The binding was insensitive to the uncouplers of photophosphorylation. The apparent binding constant was 140 μM . The binding isotherm as a function of 9AA concentration was sigmoid, and approximately 3 mol 9AA/mol chlorophyll was bound at saturating concentrations of 9AA.

Addition of Mg2+ partially reversed the binding of 9AA in chloroplasts in the dark as observed by a Mg2+-induced increase of 9AA fluorescence as well as by spectrophotom etric measurements of free 9AA. It appeared, however, that use of fluorescence techniques for m easuring free 9AA introduced an error in the estimation of the m agnitude of binding, particularly at low concentration of 9AA ( < 7 5 μM). This is probably due to change in fluorescence yield of membrane-bound 9AA on addition of cations. The nature of the binding of 9AA to the thylakoid membranes and the effects of Mg2+ thereupon suggest that both chemical binding of cations and screening of surface charge of the mem branes should be considered in discussing the mechanism of cation action on chloroplast structure and function. Interpretation of these data with respect to heterogeneity of sites of cation action upon or within chloroplast membranes is discussed.
Electromagnetically Induced Fluid Streaming as a Possible Mechanism of the Biomagnetic Orientation of Organisms
Authors: Bamberger Stephan , Valet Günter , Storch Friedrich , Ruhenstroth-Bauer Gerhard
Published: August 2018

The results show that both the direction and the intensity of the geomagnetic field can be sensed within the chamber of a Zeiss Cytopherometer. This suggests that electromagnetically induced fluid streaming might play a role in the perception of the geomagnetic field by organisms, although it is not clear at present in which organ the perception occurs. A basic requirement for such an organ would be an anisotropy of cells or cellular structures. The nervous system with its parallel axons, or specific cells associated with the nervous system, could thus be possible locations of the sensitivity towards magnetic fields.
A Novel Type of Flavonoids: Flavonol Esters from Fern Exudates
Authors: Wollenweber Eckhard , Favre-Bonvin Jean , Jay M.
Published: August 2018

Mannose exudates on fronds of Notholaena species are known to consist of navonoid aglycones. These are predominantly methylated flavones and flavonols, sometimes chalcones and dihydrochal-cones. Flavonols with unusual properties, excreted as major farina components by some species, have been found to be derivatives of methylated flavonols, esterified in position 8 with butyric or acetic acids, respectively. These are a novel type of flavonoids. They occur as twin-pairs, some with very great differences in proportions. Their presence in a group of species within the genus has chemotaxonomic implications. Two of the flavonols resulting from hydrolysis are new compounds.
Die quantitative Bestimmung von Chloroplastenpigmenten im picomol-Bereich mit Hilfe einer isochratischen HPLC-Methode/ A Method for the Quantitative Estimation of Chloroplast Pigments in the Picomole-Range by Use of a Isocratic HPLC-System
Authors: Stransky Harald
Published: August 2018

A method is described for the estimation of the pigment content in chloroplasts by means of HPLC. The method is highly sensitive. Less than one picomole of individual pigments - equivalent to 1 milligramme fresh weight of spinach leaves - is needed for quantitative analysis. Analysis time is only 15 min, whereas in routine determination by thin layer chromatography a single sample needs 4 hours to be completed.

Moreover the pigments are protected against desintegration by light and air. Using a isocratic HPLC -method no equilibration of coloumns is necessary, thus permitting four runs per hour.
Reaktionen von naszierenden Chinonen mit β-Alaninmethylester in Essigsäure und in wäßriger Lösung/ Reactions of Nascent Quinones with Methyl β-Alanate in Glacial Acetic Acid and in Aqueous Solution
Authors: Peter Martin G.
Published: August 2018

Nascent Quinones, Amine Addition In order to generate a model for the reaction of proteins with nascent quinones, catechol and 4-methylcatechol were oxidized with silver-I-oxide in glacial acetic acid or with mushroom tyrosinase (EC 1.10.3.1) in phosphate buffer, respectively. The structures identified indicate that not only the amine reacts with the quinone by the well known addition-oxidation-mechanism, but also that solvent molecules may participate in product formation. The m ain product of the oxidation of catechol in glacial acid is N-(2-carbomethoxyethyl) -phenoxaz-2,3-dione.
Über die Bestimmung von Langperioden-Änderungen am Kollagen/ On the Determination of Changes in the Large Periodic Structure of Collagen
Authors: Nemetschek Th. , Jonak R. , Nemetschek-Gansler H. , Riedl H. , Rosenbaum G.
Published: August 2018

Changes in the large periodic structure of collagen were investigated with the aid of synchrotron radiation. Following results were obtained:

1) Macroscopic extension results in elastic deformation of the elements which are determinant for the structure.

2) The increase of the large period is not proportional to the macroscopic stress.

3) The interpretation of these facts requires a mechanical coupling between the structural units. Up to extensions of 4% this coupling is produced by means of a viscoelastic matrix.

4) In all probability the polypeptide helices are deformed in an inhomogeneous mode.

The results were set against measurements on human tendon and on artificially crosslinked collagen. The relations between the mechanical behaviour and the change of the large period were compared with the properties of a mathematical model.
Dual-Wavelength Spectroscopy in Photosynthesis
Authors: Böhme Herbert , Böger Peter
Published: August 2018

Dual-wavelength spectroscopy allows the precise and fast measurement of small absorbance changes in highly absorbing and scattering samples (≦ 10-3 absorbance). The sensitivity of this method makes it possible to monitor directly redox changes of electron carriers in complex particulate biological systems. In this article, a description of the measuring principle of dual­wavelength spectroscopy is given with special reference to its application in photosynthesis.
Streulichtmessungen an ebenen Lipidmembranen. Modulation des Streulichts durch eine elektrische Wechselspannung an der Membran / Modulation of Light Scattering by an Electric Voltage at Planar Lipid Membranes
Authors: Carius W.
Published: August 2018

Light scattered at a planar lipid membrane is modulated by an electric a. c. voltage across the membrane. This effect is studied by a schlieren optic method. It shows a large contribution from the bilayer/torus border. From the inner part of the membrane no modulation of scattered light was detectable. Membranes were made from egg lecithin + cholesterol/decane in 0.1 n KCl aqueous solution.
Further Evidence for Period Lengthening Effect of Li+ on Circadian Rhythms
Authors: Hofmann Karlfriedrich , Günderoth-Palmowski Martina , Wiedenmann Gottfried , Engelmann Wolfgang
Published: August 2018

The period length of the activity rhythm of the cockroach Leucophaea maderae is increased by LiCl solution of 100 mol m-3 offered as drinking water by about 1%.
Effects of Ecdysterone and the Juvenile Hormone Analogue Methoprene on Protein, RNA and DNA Synthesis in Wing Discs of Calliphora vicina
Authors: Scheller Klaus , Karlson Peter , Bodenstein Dietrich
Published: August 2018

The protein. RNA and DNA content of wing discs increase exponentially during the last larval instar. Biosynthesis of protein, RNA and DNA was studied by injecting labelled precursors into larvae or white prepupae and measuring the incorporation in the wing discs dissected out after an appropriate time. Protein synthesis is stimulated by ecdysterone, methoprene has no effect. Bio­synthesis of rRNA is increased in wing discs of white prepupae after ecdysterone or methoprene injection. Methoprene inhibits the synthesis of mRNA, while ecdysterone has no clear-cut effect within the limits of our method (gel electrophoretic analysis). Ecdysterone and methoprene have no detectable influence on incorporation of thymidine into DNA, but the incorporation label from uridine into DNA is diminished; this effect may be due to changes in the precursor pool.
Indolalkaloide aus den Blättern vonPagiantha cerifera Markgraf [1]/ Indole Alkaloids from the Leaves of Pagiantha cerifera Markgraf [1]
Authors: Ros Hans-Peter , Schöpp Emanuel , Hesse Manfred
Published: August 2018

Olivacine, (-) -apparicine and (-)-vobasine have been isolated from leaves of Pagiantha cerifera Markgraf.
Incorporation of Positional Isomers of cis- and trans-Octadecenoic Acids into the Acyl Lipids of Cultured Soya Cells
Authors: Richter Ingolf , Weber Nikolaus , Mangold Helmut K. , Mukherjee Kumar D.
Published: August 2018

Cell suspension cultures of soya were incubated with cis-[1-14C]octadecenoic acids and trans- [1-14C]octadecenoic acids, each of known composition with regard to positional isomers. Each of the positional isomers ranging from ⊿8- to ⊿15-as-octadecenoic acids and ⊿7- to ⊿16-frans-octadecenoic acids was readily incorporated into the acyl lipids of the cells, yet, the ⊿9 cis- and the ⊿9-trans-isomers were the pre­ferred substrates, cis-trans Isomerization did not occur during the incorporation of the fatty acids into the acyl lipids.
Occurrence of N-methyl-N-formylhydrazones in Mycelia of Gyromitra esculenta
Authors: Raudaskoski Marjatta , Pyysalo Heikki
Published: August 2018

N-methyl-N-formylhydrazones, the toxic compounds identified in the fruitbodies of the false morel Gyromitra esculenta, were also found in the mycelia grown from isolated ascospores. The amounts of acetaldehyde N-m ethyl-N-formylhydrazone, the main hydrazone compound of the false morel, varied significantly among the strains studied. Especially low levels occurred in some of the strains isolated from one fruitbody.
Mössbauer Spectroscopy on Oxygenated Sperm Whale Myoglobin: Evidence for an Fe3+-O2
- Coupling at the Active Center
Authors: Bade D. , Parak F.
Published: August 2018

57Fe Mössbauer spectra of oxygenated sperm whale myoglobin (MbO2) show a well resolved quadrupole doublet with a temperature dependent splitting. The temperature dependence of the corresponding electric field gradient tensor (EFG) can be calculated from a Fe3+ term scheme for the iron at the active center. The Mössbauer spectra as well as the diamagnetic character of the MbO2-complex are then understood by an exchange coupling of the Fe3+-ion with the O2
- oxygen molecule ion. The resulting groundstate is a diamagnetic singlet. In order to keep the whole com­plex diamagnetic at room temperature, an exchange coupling with |J| ≧300cm is necessary. As the whole model is in fair agreement with many other spectroscopic data, it believed to be a good starting point for further detailed calculations.
Improved Methods for Infection of Plant Protoplasts with Viral Ribonucleic Acid
Authors: Dawson J. R. O. , Dickerson P. E. , King Janet M. , Sakai F. , Trim A. R. H. , Watts J. W.
Published: August 2018

Infection of tobacco protoplasts with RNA of tobacco mosaic virus and the bromoviruses has been studied. The quality of the RNA was very important. Ribonuclease activity was controlled by incorporating 5 mᴍ ZnCl2 in the inoculum. Up to 60% infection has been observed with bromovirus RNA but infection with TMV RNA was much less efficient. A procedure for inoculating in 40% polyethylene glycol was developed. High levels of infection were obtained with all the viruses and viral RNA examined.
Conformationally Restricted Adenine Nucleotide Analogs in Mitochondrial Adenine Nucleotide Transport
Authors: Siegfried Karl , Schlimme Eckhard , Ikehara Morio
Published: August 2018

The conformationally restricted adenine nucleotide analogs 8,3′anhydro-8-oxy-9-(β-ᴅ-xylofurano-syl) adenine-5′-O-tri (di) -phosphate (I) , and 8,2′-anhydro-8-oxy-9-(β-ᴅ-arabinofuranosyl) adenine-5′-O-tri (di)-phosphate (II), were prepared chemically as their α-32P-labelled compounds and compared with syn-structured 8-bromo AT(D) P in mitochondrial adenine nucleotide translocation.

The experimental findings demonstrate that the heterocycle-ribose orientation affects the carrier mediated adenine nucleotide transport very strongly, i. e. a non fixed adenine heterocycle in the anti region is prerequisite for the bound nucleotide to induce the transfer action of the adenine nucleotide carrier.
Über die Synthese einiger Digitalis Anthradiinone / About the Synthesis of some Digitalis Anthraquinones
Authors: Imre Sedat , Ersoy Laie
Published: August 2018

1,2,5-Trihydroxy-3-methylanthraquinone (4), 2-hydroxy-3-(hydroxymethyl)-anthraquinone (2) and three dihydroxymonomethyl-anthraquinones (5, 6, 7) have been synthesized. 2 and 4 are new synthetic compounds.
Notizen: Chemilumineszenz von Epoxiden / Chemiluminescence of Epoxides
Authors: Stauff J. , Simo I. , Tsai W . L.
Published: August 2018

Exposite produce chemiluminescence when heated to 50 - 70 °C or treated with nucleophilic substances at room temperature. Initiation by Piperidine in Dimethylsulfoxide allows to determine 5 nmol of Phenyloxirane in 5 ml samples.
Notizen: The Mutagenicity of Dichloroacetaldehyde
Authors: Löfroth Göran
Published: August 2018

Dichloroacetaldehyde, a presumed metabolite of the in­ secticides dichlorvos and tridilorphon, is mutagenic in the Salmonella/microsome test. Its mutagenic potency is higher than that of the established mutagen dichlorvos. It is pos sible that the bacterical mutagenicity test only or mainly detects the effect of methylation by dichlorvos.
Pesticides and Honey Bees: The Danger of Microencapsulated Formulations
Authors: Barker Roy J. , Lehner Yolanda , Kunzmann Michael R.
Published: August 2018

Microcapsules designed to improve the safety and persistence of pesticides are about the same size as pollen. Foraging bees collect pollen contaminated with such microcapsules and pack both together into hive combs. Sustained release formulations remain toxic in food stores of the colony. This combination of accumulation and persistence produces prolonged toxicity for bee colonies.
Notizen: The Wax of Calathea lutea (Marantaceae)
Authors: Malterud Karl Egil , Wollenweber Eckhard , P. Luis D. Gómez
Published: August 2018

Calathea lutea lives in rain forests of Central America. It produces a conspicuous wax coating on the under surface of the leaves. As contribution to the as yet rather poor chemical knowledge on the Marantaceae, the composition of this wax has been analyzed. By GLC and MS it could be shown to consist mainly of odd numbered re-alkanes and even numbered n-alkanols.
Characterization of the Metamitron Deaminating Enzyme Activity from Sugar Beet ( Beta vulgaris L.) Leaves
Authors: Fedtke Carl , Schmidt Robert R.
Published: August 2018

The enzymatic activity from sugar beet leaves which is responsible for the detoxification of the herbicide metamitron (4-amino-4,5-dihydro-3-methyl-6-phenyl-1, 2, 4-triazin-5-one, trade name Goltix®) has been characterized in vitro. The detoxification occurs by rapid deamination in vivo as well as in vitro. However, the deamination in vitro is only maximal under reducing conditions, i. e. with an electron donor and in a nitrogen atmosphere. The electron donor may be cystein, glutathione, dithionite or ascorbate. The enzymatic deamination further requires the addition of cytochrome c and a “supernatant factor”, which may be replaced by FMN, FAD or DCPIP. However, in the presence of FMN or DCPIP cytochrome c is not essential but only stimulatory. The partic­ulate as well as the soluble metamitron deaminating enzyme preparations obtained take up oxygen when supplied with cysteine and FMN. The particulate enzyme appears in the peroxysome-fraction.

It is therefore suggested, that the enzymatic deamination of metamitron in sugar beet leaves is mediated by a proxisomal membrane bound electron transport system which alternatively may reduce oxygen or metamitron (deaminating).
Die Wirkung 2.3-substituierter Naphthochinone auf einzellige Algen und isolierte Spinatchloroplasten/ The Effect of 2,3-Substituted Naphthoquinones on Unicellular Algae and Isolated Spinach Chloroplasts
Authors: Bauer Klaus , Kodier Helmu
Published: August 2018

Short term effects of 2-(C-dichloro-acetylamino)-3-chloro-1,4-naphthoquinone (Hoe 13465, quinonamid*) and 2-amino-3-chloro-1,4-naphthoquinone (Hoe 17399, 06K-quinone) on cell suspensions of Chlorella vulgaris, Anabaena flos aquae, Porphyridium cruentum, and on isolated spinach chloroplasts were studied.

The results clearly show that both substances inhibit the photosynthetic O2 production of algal suspensions as well as the electron transport of PS II in spinach chloroplasts. PS I is not inhibited by the action of the two algicides. At low concentrations quinonamid acts as a photosynthetic electron transport blocker, whereas Hoe 17399 is a weak inhibitor of photosynthetic electron flow. Mode of action of the two naphthoquinones is discussed.

Both naphthoquinone derivatives can operate as an electron acceptor for PS I at low concentra­tions (10-5-10-6м). In addition there is observed a strong stimulation of dark respiration in algal cells induced by both of the compounds, Hoe 17399 causes a much higher stimulation rate than quinonamid does.
Neuere Ergebnisse zur Struktur-Aktivitäts-Beziehung/ Some New Results Concerning Structure-Activity Relationships of Herbicides
Authors: Draber Wilfried
Published: August 2018

Relative activities and sensitivities towards twelve 1,2,4-triazinones were determined by conventional dilution techniques. The pI50-values of photosynthesis inhibition were found in a very narrow range (6.4 -6.6) whereas their physical properties differed widely (RM , log PO/W * log PSE , log (1/c) W). The question was whether the physical parameters showed any correlation with the relative activities and relative sensitivities which differed very widely (up to 50 fold). It was found that only the water solubility (log (1/c) W) showed some correlation with activity and no correlation could be detected between the chemical structures and the activities or sensitivities.
Carotenoid Biosynthesis — a Target for Herbicide Activity
Authors: Britton George
Published: August 2018

Carotenoids are chloroplast constituents. In vivo different carotenoids may be present at different sites within the chloroplast, and may have different functions. Especially important is a role in protecting the chloroplast and hence the plant from chlorophyll-sensitized photooxidation. If carotenoid biosynthesis can be blocked by herbicides, such protection will no longer be afforded, and rapid death of the plant is likely. In this article current knowledge of carotenoid biosynthesis is reviewed. The main characteristics of each stage in the biosynthesis are outlined and the suit­ability of these reactions as possible herbicide targets is assessed. Two experimental approaches to the study of the effects of herbicides on carotenoid biosynthesis are suggested.
Studies about the Mechanism of Herbicidal Interaction with Photosystem II in Isolated Chloroplasts
Authors: Renger Gernot
Published: August 2018

Based on the functional organization scheme of system-II-electron transport and its modification by different procedures a proteinaceous component enwrapping the redox components (plastoquinone molecules) of the acceptor side (thereby acting as regulatory element) is inferred to be the unique target for herbicidal interaction with system II. This proteinaceous component, which is attacked by trypsin, provides the receptor sites for the herbicides. Studies of the release kinetics in trypsinated chloroplasts of the inhibition of oxygen evolution with K3 [Fe (CN)6] as electron acceptor indicates, that there exists a binding area with different specific subreceptor sites rather than a unique binding site for the various types of inhibitors. Furthermore, trypsination of the proteinaceous component enhances the efficiency of the plastoquinone pool to act as a non-photochemical quencher for excitation energy.
Mechanism of Paraquat Action: Inhibition of the Herbicidal Effect by a Copper Chelate with Superoxide Dismutating Activity
Authors: Youngman Richard J. , Dodge Alan D.
Published: August 2018

The treatment of flax cotyledons (Linum usitatissimum) with paraquat was shown to decrease the levels of chlorophyll and carotenoid pigments. The fatty acid content of chloroplast fragments isolated from treated tissue was determined and shown to be greatly decreased by paraquat treat­ment. The superoxide radical was demonstrated to play an important role in the phytotoxic action of paraquat by the use of a copper chelate of D-penicillamine, which has a high superoxide dismutating activity. The action of paraquat was inhibited by this compound. The role of superoxide is discussed with reference to the generation of more toxic species, such as singlet oxygen.
Influence of Bleaching Herbicides on Chlorophyll and Carotenoids
Authors: Kunert Karl-Josef , Böger Peter
Published: August 2018

Over 24 and 48 hour cultivation periods the influence of SAN 9789 (norflurazon), EMD-IT 5914 (difunon) and fluridone on growth, photosynthetic oxygen evolution and pigment content of the green alga Scenedesmus acutus was determined. Four effects were observed:

a) Both carotenoid and chlorophyll formation were inhibited.

b) Carotenoids were destroyed in the presence of air, but not nitrogen. The level of chlorophyll, however, did not change.

c) β- (and α-) carotene was markedly decreased in the presence of oxygen.

d) Photosynthetic oxygen evolution was decreased with the disappearance of carotenoids.

These effects, which are accompanied by reduced growth, are believed to represent primary herbicidal modes of action. The decrease of oxygen evolution is not due to a direct inhibition of photosynthetic electron transport by the herbicides applied.
Ribose Conformations of Adenosine Analogs Modified at the 2', 3' or 5' Positions
Authors: Klimke G. , Cuno I. , Lüdemann H.-D. , Mengel R. , Robins M. J.
Published: August 2018

The solution conformation of adenosine(β)ribosides modified at the 2′, 3′ or 5′ position is derived from the analysis of the HRNMR spectra of the ribose protons. The conformational equilibria of the furanoside rings are described by the two state N ↔ S model introduced by Altona and Sundaralingam. The new compounds studied are: 2′-thiobenzoyl-2′-deoxyadenosine, 3′-thio-3′-deoxyadenosine, 2′-chloro-2′-deoxyadenosine, 3′-chloro-3′-deoxyadenosine, 2′-bromo- 2′-deoxyadenosine, 3′-bromo-3′-deoxyadenosine, 2′-O-methyladenosine, 3′-O-methyl-adenosine, 2,-deoxy-3,-O-methyladenosine, 5′-amino-5′-deoxyadenosine, 5′-acido-5′-deoxyadenosine, and 5′-chloro-5′-deoxyadenosine.

The emphasis in this work is to study systematically the influence of the different substituents upon the conformational equilibria of the sugar. It is found that any substitution at the 2′ position stabilizes the S-conformer. An even more pronounced stabilization of the A-conformer in the 3′ substituted analogs is observed. The equilibrium changes in these classes of compounds can neither be correlated quantitatively with electronegativity differences nor with sterical differences between the various substituents. Substitution at the 5′ position influences the N ↔ S equilibrium only slightly, but has significant effects upon the conformational preferences of the exocyclic 5′-CH2R3 group.
Investigations on Hoya Species. III. Leaf Phenolics and Latex Lipids of Hoya lacunosa Bl.
Authors: Niemann Gerard J. , Baas Wim J. , Besson Elisabeth , Chopin Jean
Published: August 2018

Hoya lacunosa leaves contain some main C-glycosylflavonoids, which were identified as: 6-C- arabinosyl 8-C-glucosylapigenin (isoschaftoside), 6-C-glucosyl 8-C-arabinosylapigenin (schaftosi- de) and 6,8-di-C-arabinosylapigenin. In the latex triterpenols were found, often both free and in ester form, of which β-amyrin, α-amyrin, lupeol, 24-methylenecycloartanol, obtusifoliol and cycloeucalenol were identified in the free alcohol fraction. The esters, forming the major part of the to­tal lipid fraction, were solely acetates of some of the above mentioned alcohols.
Radiation Aggregates of Insulin
Authors: Kopoldová Jiřina
Published: August 2018

During the irradiation of aqueous solution of insulin (pH 1.8) the decrease of original insulin molecules and the formation of radiation aggregates of insulin was studied in dependence on the concentration of irradiation solution, on the doses and conditions of irradiation (oxygenated and oxygen-free atmosphere, the presence of t-butanol, addition of [14C] amino acids). From the results obtained and results published earlier it may be assumed that in irradiated solution on insulin new covalent bonds between insulin molecules are formed at tyrosyl, phenylalanyl and cystyl radicals; these radicals are formed by the action of both direct and indirect effect (at present pH 1.8 mainly of H atoms).
Accumulation of Photoassimilatory Products by Phycobiliprotein- Containing Algae with Special Reference to Cyanidium caldarium
Authors: Kremer Bruno P. , Feige Guido B.
Published: August 2018

Representatives of phycobiliprotein-containing algae such as Anabaena cylindrica, Anacystis ni- dulans, Gloeotrichia echinulata (Cyanophyceae), Chroomonas spec., Hemiselmis rufescens, Rhodomonas spec. (Cryptophyceae), Porphyridium cruentum, Rhodella violacea (Rhodophyceae) along with the unicellular Cyanidium caldarium (unspecified systematic status) have been investigated for their typical photoassimilatory accumulation products. While the red algal species synthesize a rather specific heteroside, 2-O-ᴅ-glycerol-α-ᴅ-galactopyranoside (= floridoside), not encountered in the other species analyzed, blue-green algae accumulate fructose, glucose, and sucrose, while the cryptomonads accumulate only glucose and. to a lesser extent, fructose. Cyanidium synthesizes neither disaccharides, nor a heteroside, but shows rapid 14C-labelling of fructose and glucose. These results are compared with further biochemical and structural findings and are discussed with emphasis on chemotaxonomic implications. Cyanidium caldarium is proposed as an endocyanome consisting of a single endocyanella providing the functions of a chromatophore in a colourless (apoplastidal algal?) host cell.
Permeability of Plasma Membrane Vesicles to Ouabain and Mg2+ as a Factor Determining Rate of Binding of Ouabain to Na+ and K+ Dependent ATPase
Authors: Walter Horst
Published: August 2018

Na+, K+-ATPase of the plasma membrane isolated from sheep kidney medulla exhibits functio­nal asymmetry for the cardiac glycoside ouabain. In this vesicular membrane preparation the rate of binding of ouabain was slow (time constant > 60 min) when the vesicles were incubated in the presence of isotonic sucrose. Upon treatment of the preparation with hypoosmotic shock or phos­pholipase A the initial rate of ouabain binding was enhanced at least 3 fold. In equilibrium a concentration of the ouabain-enzyme-complex was obtained which was about twofold that of the untreated vesicles. This result suggests two types of ouabain binding sites with an approximate stoichiometry of 1 to 1. The stoichiometry seems to be maintained at high concentrations of ouabain where binding curves show a biphasic time course. Additional information about hetero­geneity of binding sites comes through experiments in which the vesicles were treated with Mg2+ prior to the addition of ouabain. A minor fraction of the binding sites were occupied by ouabain only after longtime incubation with Mg2+.
A Sex Attractant for the Green Budworm Moth, Hedya nubiferana
Authors: Frerot Brigitte , Priesner Ernst , Gallois Martine
Published: August 2018

The two major components of the female pheromone blend of Hedya nubiferana have been identified as (E, E)-8,10-dodecadienyl acetate and (Z)-8-dodecenyl acetate. Each compound acts on a specialist receptor type in olfactory hair sensilla of the male antenna. In field screening tests, combinations of the two compounds and dodecanyl acetate were highly attractive to H. nubiferana males. The (Z, E)-8,10 isomer attracted males of Hedya ochroleucana.
A Radioactive 1,4-Benzoquinone as Inhibitor of the DBMIB-Type in Photosynthetic Electron Transport
Authors: Oettmeier Walter
Published: August 2018

An 125iodine labelled 1,4-benzoquinone, an analogue of DBMIB, was studied for its interaction with the photosynthetic system of chloroplasts. It is not covalently bound to the thylakoid mem­brane. Instead, chloroplasts slowly decompose it under release of 125iodine and formation of a quinone of only small inhibitory potency, i. e. photosynthetic activity is restored after a few minutes. The inhibition in photosynthetic electron transport caused by the 125iodine labelled 1,4-benzoquinone can also be neutralized by bovine serum albumin to which it binds covalently.
Structural Differences in the Tracheal Tapetum of Diurnal Butterflies
Authors: Ribi Willi A.
Published: August 2018

The three-dimensional structure of the tracheal tapetum lucidum, its reflection properties and the resulting eye glow hue were studied in members of the diurnal butterfly families Pieridae, Nymphalidae, Satyridae and Lycaenidae. Two main groups of tapeta can be distinguished by structural and physiological differences. Whereas in pierids the main tracheal trunk at the bottom of the rhabdom bifurcates into two side branches before bifurcating again more distally, the tracheal trunk in the members of the family Nymphalidae, Satyridae and Lycaenidae investigated first divides into four side brandies. A second bifurcation shortly after the first results in eight subbranches which are regularly arranged between adjoining receptor cells. The broad banded reflection colour from incidently illuminated tapetal structures (at the level of the first bifurcation) varies between and within families but does not change significantly within the same eye. Whereas in nymphalids, satyrids and lycaenids the eye glow hue corresponds with the colour of the tapetal reflection, in pierids it is dominated by the coloured receptor screening pigment.
Transcription and Release of RNA in Isolated Nuclei from Parsley Cells
Authors: Großmann Klaus , Seitz Ursula , Seitz Hanns Ulrich
Published: August 2018

An in vitro transcription system using nuclei from freely suspended callus cells of Petroselinum crispum is described. The use of a filtration technique allowed the measurement of transcription and release of RNA simultaneously over very short time intervals. The transcription showed a biphasic time course, with an early maximum at 2 and a later one at 20 minutes. The early maximum was ascribed to the activity of polymerase II (α-amanitin sensitive), the later to that of polymerase I. While the transcriptional process was independent of the temperature used for incubation up to 26 °C and even increased with temperatures above that, the release of RNA transcribed was inhibited by temperatures above 36 °C.
The Influence of Spermine, Spermidine and Various Sera on T-Lymphocyte and Granulocyte Colony Growth in vitro
Authors: Rainer H. , Maschler Reinhard
Published: August 2018

Using T-lymphocyte (T-LC) and granulocyte colony (GC) assays with truly proliferating cells, the dose-response relationships of spermine and spermidine, of fetal calf (FCS), calf (CS), horse (HS) and human AB serum (A B S), and of the polyamines in the presence of selected does of the sera were analyzed. In contrast to earlier observations using [3H] thymidine uptake measure­ ments it was found that the polyamines as well as the sera themselves inhibit T-LC and GC growth in the presence of autologous HS and ABS, respectively. The polyamines also inhibit in the presence of additional HS and ABS, yet most effectively with added FCS and CS. Thus the previously reported species-specificity of the serum-dependent polyamine inhibition has here been shown to be more quantitative than qualitative. These studies stress the significance of assays utilizing truly dividing cells and broad dose-response relationships in order to assess specific biological effects in vitro.
Messungen der Spin-Gitter-Relaxationszeit T1 an Nucleosiden / Spin-Lattice-Relaxationtime T1 Measurements of Nucleosides
Authors: Sterk H. , Kopp H. , Esterbauer H.
Published: August 2018

Nucleosides and nucleotides have been investigated by means of the spin-lattice-relaxationtim T1 , the measurements carried out in CDCl3 on the nucleosides adenosine (A), uridine (U) and inosine (I) indicate that the strength of H-bonding is highest in the basepair (A)-(U). The systems (A)-(A), (U)-(U) , (I)-(A) ana (I)-(U) however, show only a low tendency to associate. Plotting the spin-lattice-relaxationtime, of the nucleotide protons in fragments (mol weight below 40,000) originated from DNA or RNA, against increasing temperature gives a curve with a sigmoide shape and a Tm value of 80 °C. The average of the activation energy for the H-bonding is 18.02 KJ/mol. The investigations clearly show that the spin-lattice-relaxationtime measurements open first of all a new method for research on H-bonding, secondly it is even in the case of nucleosides and oligonucleotides, where most of the common methods fail, a way to get information about H-bonding effects.
A Viscosity Model of Polyacrylamide Gel Electrophoresis
Authors: Bode Hans-Joachim
Published: August 2018

In current theories of polyacrylamide gel electrophoresis, the idea prevails that molecular siev­ing relies on different accessibility of volume fractions and of cross-sectional area fractions (denot­ed “pores”) to different-sized ions due to the effect of “geometric exclusion”. This correlates with the assumption that all elements of a polyacrylamide network occupy fixed and unchangeable po­sitions thus forcing colliding macro-ions to diffuse laterally in order to find an “accessible pore” and to resume motion in direction of the electrical field. However, the alternative conception would be equally well justified, i. e. the assumption that polyacrylamide chains represent smooth obstacles cleared aside under the electrokinetic pressure of a macro-ion. This explanation would even be preferable with respect to the molecular sieving effects occuring in solutions of “liquid polyacrylamide”. Yet no theory exists as to describe such effects in quantitative terms.

In the present article, a parameter is defined and discussed, which can be estimated by experi­ment, and which seems to be apt to characterize local resistivity of polymer structures against dis­location and deformation: the “fractional specific resistance”. Definition of this parameter is bas­ed on the model of a “viscosity-emulsion” composed of two interpenetrating liquid compartments which are characterized by different levels of hydrodynamic friction and the spatial dimensions of which are inferred from Ogston’s theory. This concept of “localized viscosity” may also serve as a link between theories of molecular sieving and of “macroscopic viscosity” of flexible polymers. The data of Morris, formerly taken as verifications of the “rigid-pore” concept, are now interpret­ed in terms of four factors responsible for sizediscrimination: collision frequency, duration of sin­gle contacts, size-dependent frictional force, and the extent of cooperation among fibres, due to crosslinking and to simultanous contacts of several fibres to a single macro-ion. Some functions rel­evant for problems of molecular weight determination by gel electrophoresis are discussed in rela­tion to the suggested model.