bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light-Dependent Changes in the Lipid and Fatty Acid Composition of Phycocyanin-Free Photosynthetic Lamellae of Synechococcus
Authors: Datz Günter , Döhler Günter 
Published: August 2018

Abstract
The growth of Synechococcus at different intensities of white and red light caused changes in the pigment composition. The ratio of chlorophyll a to phycocyanin varied from 1:8,2 in LWLI-grown cells to 1:1,4 in cells grown at HWLI and to 1:15,7 in cultures exposed to HRLI. Acyl lipids were quantitatively determ ined and fatty acids of the individual lipid classes analysed by GLC. Phycocyanin-free photosynthetic lam ellae were obtained by fractional centrifugation. No variation was found in the acyl lipid composition of the m em brane preparations. These all contained MGDG, DGDG, SQDG and PG as components. In all the lipids investigated, palmitic, hexadecenoic and octadecenoic acids m ade up to more than 90% of total fatty acids. The pattern of these major components w ithin the lipids from the different cultures depended on the light used. No large differences were detected between zones obtained from LWLI and HRLI isolated membranes, whereas density gradient centrifugation of those from HWLI-grown cells resulted in a completely different pattern of bands. The variations in lipid and fatty acid composition are discussed with respect to changes observed in lipid composition of whole cells and the results reported on tem perature dependent shifts in lipid fluidity in cyanobacteria.
X-Ray Studies on Phospholipid Bilayers I. Polymorphic Forms of Dimyristoyl Lecithin
Authors: Suwalsky M. , Tapia J. 
Published: August 2018

Abstract
A structural study of the synthetic phospholipid, L-a-dimyristoyl lecithin (DM L), has been m ade by X-ray fiber diffraction methods. Three different types of oriented specimens were prepared. They were X-ray photographed under the same conditions, including tem perature and relative humidity. T hree different types of diffraction patterns, corresponding to different confor­ mations and/or packing arrangements, were found. They are characterized by their unit cell dimensions, space groups, molecular conformations, and packing arrangements.
Titration of Rat Liver with Digitonin: a Well Defined Short Term Damage of Cellular Metabolism
Authors: Postius Stefan , Platt Dieter 
Published: August 2018

Abstract
Carefully performed pulse titration of the isolated rat liver in the course of continuous erythro­ cyte free perfusion with small amounts of digitonin causes a short term perm eability of liver cell plasma membranes with concomitant short lived release of intracellular low or high molecular compounds such as ATP or lactate dehydrogenase. Gluconeogenesis from lactate being completely inhibited during this period restores w ithin about one m inute up to a level that depends on the am ount of perfused digitonin. The described experimental m odel is suggested to be useful for the measurement of cytoplasmic m etabolites under physiological conditions. It moreover offers the possibility to im port foreign substances into liver cells th at normally do not penetrate liver cell plasma membranes.
On the Role of Hydrogen Peroxide in Peroxidase Catalyzed Metabolism of Indole-3-acetic Acid
Authors: Grambow Hans J. 
Published: August 2018

Abstract
Formation of H2O2 in the course of peroxidase catalyzed IAA metabolism was measured using the peroxide-dependent decarboxylation of [14C]glyoxylate and the oxidation of phenolic substrates giving rise to fluorescent products in IAA/HRP systems. The results agree with the recent concept of IAA metabolism which includes the formation of H2O2 in the course of oxidase action on IAA and the consumption of this H2O2 by subsequent peroxidase action in the presence of phenolic cosubstrates.
Polycation-Bacterium Interactions and Wall Subunits as Endocytosis Factors. Topoisomeraselike Action of Basic Polypeptides Suggesting a 7th Class of Enzymes: The Stereases
Authors: Antohi Stefan 
Published: August 2018

Abstract
Lysine rich histone and polylysine are bacteriolytic for Bacillus subtilis and Escherichia coli cells, whereas histones H2A, H2B and H3, assayed separately are not. Polyarginine bacteriolysis of E. coli with polycation 10 μg/ml decreased with higher concentrations, the killed nonlysed cells exhibiting wall alterations. All bacteriolytic polycations were lytically effective under reciprocal shaking, but not under magnetic stirring conditions, demonstrating the requirement for cell lysis of mechanical fields developed in oscillatory movements. Scanning electron microscopy of histone H1 treated B. subtilis cells showed the formation of globular bodies (polionosomes) in the cell surface. The interference of Ca2+ and 0 °C exposure with the polycation action observed especially in E. coli, the polionosomes, and the dynamics in polycationic cell lysis, considered together, suggest the existence o f wall supramolecular subunits (murameres), defined by their ability to form polionosomes. The murameres undergoing reversible conformational transitions induced by ectobiological signals, e.g., Ca2+, would make up an uptake system. The involvement of this system in environmental interactions and DNA uptaking, as well as the general stereo-enzyme like nature o f the conformational changes caused by polycations are discussed.
Thermodynamic Approach to a Possible Theory of the Evolution of a Genetic Code
Authors: Macchiato M. F. , Tramontano A. 
Published: August 2018

Abstract
One of the distinctive features of a biological system is its remoteness from equilibrium: for the treatment of the information exchanged by these systems with the external world the concept of information amount is not sufficient because for nonequilibrium systems we need further specifications about information, i. e. its value.
We defined the information value for a genetic code. The comparison of the results we had applying such a definition to the three genetic codes found in nature shows that our definition described the system of transmission and reception of information in a biological organism very well and that the information value of a genetic code can be considered as an index of its efficiency, i.e. of its ability to minimize the effects of a mutation of the genotype on the phenotype.
Otherwise, our results show that the information value, and hence the efficiency of the three known codes is the same and suggest that the prerequisite of the evolution of the codes is the preservation of this value.
Naramycin B, an Antibiotic from Streptomyces griseus Strain 587 with Herbicidal Properties-Fermentation, Isolation, and Identification
Authors: Berg Dieter , Schedel Michael , Schmidt Robert R. , Ditgens Klaus , Weyland Horst 
Published: August 2018

Abstract
From the culture filtrate of Streptomyces griseus strain 587 a herbicidal active fraction was isolated by adsorption on Lewapol® , methanolic desorption, and chromatography on Sephadex® LH-20. Further purification was achieved by HPLC. The pure product was characterized by TLC and different colour reactions. By MS, 1H-NM R, IR and ORD spectroscopy the herbicidal compound could be identified as naramycin B. Naramycin B is an optical isomer of cycloheximide (naramycin A, Actidione®, Acti-Aid®). This communication reports on the fermentative production of naramycin B with strain 587, its isolation, identification, and herbicidal activity.
Localization of Ca2+ at the Plasma Membrane of Bullfrog Myocardial Cells
Authors: Meyer R. , Schmitz M. , Stockem W. , Haas H. G. 
Published: August 2018

Abstract
Cellular distribution and localization of Ca2+ in bullfrog myocardial cells was investigated on the light and electron microscopical level using different preparation procedures. Fixation and dehydration in glutaraldehyde and ethanol solutions containing increased amounts of Ca2+ (5-25 mᴍ) cause the formation of numerous electron-dense deposits at the external face of the sarcolemma. X-ray microanalysis demonstrates that the deposits are mainly composed of calcium. Similar results were obtained in cryopreparations by quick-freezing of fresh myocardial tissue. Granules with a diameter of 16.6 nm, which clearly exceed all other cell constituents in contrast, are found at the entire myocardial cell surface. Besides an increased amount of calcium the granules contain potassium and phosphorus. Fluorescence microscopy on single cells obtained from bullfrog atrium by treatment with digestive enzymes and stained with chlorotetra-cycline (CTC) as a fluorescent probe for membrane-bound Ca2+ clearly support the observations made on the fine structural level. A strong fluorescence signal depending on the CTC-and Ca2+-concentration of the incubation medium is observed at the sarcolemma and can be inhibited by addition of La3+.
The results of the present investigation suggest that the surface coat of the sarcolemma of myocardial cells represents an important compartment for accumulation and release of external Ca2+. The external lamina which partly covers the surface of myocardial cells seems not to be involved in the Ca2+ exchange.
Induktion von Einzel-und Doppelstrangbrüchen in linearer und superzirkularer DNA durch Phleomycin / Induction of Single-and Double-Strand Breaks in Linear and Superhelical DNA by Phleomycin
Authors: Schmülling Franz , Köhnlein Wolfgang 
Published: August 2018

Abstract
Phleomycin induced DNA breakage was investigated with superhelical Col. E1 DNA and linear T2 DNA as well. In both DNA-forms besides single-strand breaks direct double-strand breaks were produced by the drug. The double-strand breakage rate obtained after treatment with phleomycin, however, was considerably smaller than that found after bleomycin treatment. Whereas the single-and double-strand breakage rate in Col. E1 DNA showed a linear and nearly quadratic dependence on the phleomycin concentration, respectively, in T2 DNA the breakage rates increased faster than the first or second power of the concentration. This indicates various modes of drug-DNA interaction. Under nondegrading conditions a strong retardation of electrophoretic mobility was observed for all three topological isomers of Col. E1 DNA whereas the sedimentation behaviour remained unchanged.
The in vitro effects (strand breakage) of phleomycin and bleomycin are compared with in­ duction of chromosomal aberrations in human lymphocytes and oocytes of Drosophila melanogaster.
Effect of Water Soluble Polymer, Polyethyleneglycol, and Glass-Forming Compounds on Cell Fusion
Authors: Yoshii Fumio , Kaetsu Isao 
Published: August 2018

Abstract
The cell fusion of Molt T-cells was investigated in the presence of water soluble polymer, polyethyleneglycol (PEG) and glass-forming monomers. In cell fusion with PEG only, inactivation of the cell occurred within 2 min. However, in the presence of PEG and water soluble polymer, most of the fused and unfused cells lived even after fusion times of more than 10 min. It was observed that water soluble polymer prevented the inactivation of cells during fusion as a protectant. As the result, ratio of fused cells increased in the presence of water soluble polymers.
Some glass-forming monomers used as new fusogens such as M-23G (n = 23) and M-50G (n = 50) monomers having long oxyethylene chains in the methoxypolyethyleneglycol methacrylate, CH3O-(-CH2CH2-O)n-CO-C(CH3)=CH2 as well as PEG #2000 indicated large promoting and protecting effects on cell fusion.
Inactivation of the Sarcoplasmic Reticulum Calcium -Transport-ATPase by Lasolocid in Combination with Triton X-100
Authors: Hasselbach Wilhelm , Lüdi Hans , Migala Andrea 
Published: August 2018

Abstract
The calcium-transport-ATPase of the sarcoplasmic reti­culum membranes is irreversibly inactivated by the combined action of Lasolocid and Triton X-100 at concentrations which separately do not interfere with the enzyme's activity. In the presence of Lasolocid the enzyme is most susceptable to inactivation when the Triton X-100 concentration just exceeds its critical micellar concentration, ~ 0.2 mg · ml-1. Lasolocid becomes effective at a concentration of 10 μᴍ and produces rapid inactivation at 100 μᴍ . The enzyme is more rapidly inactivated in the active than in the inactive state.
Structure Elucidation of Pterosupin from Pterocarpus marsupium, the First Naturally Occurring C-Glycosyl-β-hydroxy-dihydrochalcone
Authors: Adinarayana Dama , Syamasundar Kodakandla Venkata , Seligmann Otto , Wagner Hildebert 
Published: August 2018

Abstract
The chemical examination of Pterocarpusm arsupium root afforded pterosupin, a new C-glu-cosyl-β-hydroxydihydrochalcone along with pseudobaptigenin, liquiritigenin, isoliquiritigenin, garbanzol, 5-deoxy-kaempferol and p-hydroxybenzaldehyde.
Rubins and Rubinoid Addition Products from Phycocyanin
Authors: Küfer W. , Scheer H. 
Published: August 2018

Abstract
The verdin-type Chromophore of denatured C-phycocyanin (1) from Spirulina platensis is reduced to the corresponding rubin (2a) by sodium borohydride. The structure assigned is in agreement with the uv-vis spectroscopic properties of the product and was deduced from model studies with free bile pigments.
Analogous model studies using sodium dithionite demonstrated a two-fold reactivity for this reagent, leading to products which are both o f the rubin spectral type under the conditions tested. True rubins (10,22-dihydrobilindions) are formed in low yield only if an excess of reagent is used in methanol/water mixtures. It is accompanied by polar addition product(s) of the same spectral type, which are generally formed exclusively. In particular, no bilirubin was formed under the reaction conditions previously applied for the chemical modification of phycobiliproteins and phytochrome. From this finding and from the strikingly different properties of the borohydride and dithionite products, of phycocyanin upon renaturation, the dithionite product is suggested to be a rubinoid addition product (2b) rather than a hydrogenation product.
In contrast to the dithionite addition product 2b of phycocyanin, the chromophore of the true phycorubin (2a) remains stable upon renaturation. The uv-vis spectral properties of the chromophore are not markedly different whether the apoprotein is in its native or denatured state. The different electrophoretic mobilities of native (renatured) phycocyanin compared to the renatured borohydride product suggest that these two have different protein conformations.
The preparation of these phycorubins renders the extensive techniques of bilirubin chemistry applicable in the study of biliproteins.
The Influence of Detergents on the Ca2+-and Mg2+-Dependent Adenosine Triphosphatase of the Sarcoplasmic Reticulum
Authors: Lüdi Hans , Rauch Bernhard , Hasselbach Wilhelm 
Published: August 2018

Abstract
During the stepwise solubilization of sarcoplasmic reticulum vesicles with detergents, the following changes in the structural and enzymatic properties of the preparation are observed:
1. The viscosity of the vesicular suspension initially rises. This change is accompanied by the formation of elongated tubules. Subsequently the membranes are completely desintegrated, resulting in a considerable reduction of the viscosity.
2. A decrease in the activity of the Ca2+-dependent ATPase, which is restored after complete solubilization.
3. A decrease in the change of intrinsic tryptophan-fluorescence on removal of calcium ions, which is also restored after complete solubilization.
4. A decrease of the calcium affinity of the ATPase.
5. A decrease in the amount of phosphorylated protein formed by the incorporation of inorganic phosphate. On the other hand, the amount of phosphoprotein formed from ATP is not affected during solubilization.
6. The dependence of the initial rates of phosphoprotein formation from inorganic phosphate on either magnesium or inorganic phosphate at low concentrations of the respective ligand changes from an S-shape profile to a normal hyperbolic profile after solubilization.
Periodicities of Dinucleotide Self-Information Values in Φ X174 DNA
Authors: Furlong N. Burr , Beckner C. F. 
Published: August 2018

Abstract
The natural DNA sequence of bacteriophage, ΦX174, when analyzed as a "text" of dinucleo­ tides, is shown to display an easily detectable degree of non-randomness by the distribution of values of dinucleotide self-information along the sequence. Self-information corresponding to occurrences of dinucleotides separated by a single nucleotide is found to be somewhat higher than the values which preceed or follow it for every third nucleotide position along the sequence. Consequently autocorrelation coefficients of these values display a strong periodicity and harmonic analysis of the values shows a spike at a value of 3. Self-information autocorrelation periodicity is used as a test of the effect of randomizing portions of the sequence. Any one or two of the three nucleotides in each triplet of the sequence can be chosen at random without losing dinucleotide self-information periodicity except when both the 1st and 3rd nucleotide of all of the triplets in the major ΦX174 protein reading frame are randomized. Periodicity is also lost when sequences are generated by randomizing triplets.
Autocorrelation and harmonic analysis also indicate other less marked periodic features of dinucleotide self-information values of the native sequence; non-random features are suggested at periods of 12,20 and 24 nucleotides.
Die Bedeutung der Verknüpfungsposition des Adenosins im NAD+ für die Coenzymaktivität gegenüber Lactatdehydrogenase / The Importance of the Position of the Adenosine Linkage in NAD+ for Its Coenzyme Activity via Lactate Dehydrogenase
Authors: Schlimme Eckhard , Mattem Roland , Schott Eberhard 
Published: August 2018

Abstract
We report on the chemical preparation of the NAD+ analog P1, P2-(5′-β-nicotinamideribofuranosyl-3″-adeno-syl)-diphosphate (N3″AD+) by applying the 1,1′-carbonyl-diimidazole activation method. The importance of how adenosine is linked to the nicotinamide mononucleotide phosphoriboride (NMNPR+) moiety is discussed with re­ spect to the coenzyme activity in the lactate dehydrogenase catalyzed reaction.
Proton NMR-Relaxation Dispersion in Meconium Solutions and Healthy Amniotic Fluid: Possible Applications to Medical Diagnosis
Authors: Béné Georges J. , Borcard Bernard , Graf Volker , Hiltbrand Emile , Magnin Patric , Noack Friedrich 
Published: August 2018

Abstract
In order to show that for a possible application in medical diagnosis NMR-relaxation experiments at low Larmor frequencies (v0 ≤ 20 kHz) are more sensitive than the up to now done high field measurements in the MHz-range, we present dispersion curves (v0 = 50 Hz to 50 MHz) of the proton longitudinal relaxation time T1 and values of the transversal relaxation time T2 for the example of amniotic fluids. Only for Larmor frequencies below ≃ 100 kHz the relaxation times for healthy amniotic fluid and pathological meconium solutions are significantly different, whereas at high Larmor frequencies, i. e. in the conventional MHz-range, the observed changes are rather small.
Adaptation of Chloroplast-Ultrastructure and of Chlorophyll- Protein Levels to High-Light and Low-Light Growth Conditions
Authors: Lichtenthaler H. K. , Kuhn G. , Prenzel U. , Buschmann C. , Meier D. 
Published: August 2018

Abstract
Adaptation In saturating light radish seedlings grown in high-light growth conditions (90 W · m-2) possess a much higher photosynthetic capacity on a chlorophyll and leaf area basis than the low-light grown plants (10 W · m-2). The higher CO2-fixation rate of HL-plants is due to the presence of HL-chloroplasts which possess a different ultrastructure and also different levels of the individual chlorophyll-carotenoid-proteins than the LL-chloroplasts of LL-seedlings.
1. Ultrastructure: The high-light adapted chloroplasts are characterized by fewer photo­ synthetic membranes per chloroplast section, by low grana stacks (only few thylakoids per granum), a lower stacking degree of thylakoids, a higher proportion of non-appressed membranes (stroma thylakoids + end grana membranes) and a high starch content. The LL-chloroplasts possess no starch, their grana stacks are higher (up to 17 thylakoids per granum) and also significantly broader than that of HL-chloroplasts.
2. Chlorophyll-proteins: The photosynthetic apparatus of HL-chloroplasts contains a larger proportion of chlorophyll a-proteins of photosystem I (CPIa + CPI) and of photosystem II (CPa, the presumable reaction center of PS II) than the LL-chloroplasts which possess a higher proportion of light-harvesting chlorophyll a/b-proteins (LHCP1, LHCP2, LHCP3, LHCPy). The higher levels of LHCPs in LL-plants are associated with a higher ground fluorescence fo and maximum fluorescence fp of the in vivo chlorophyll.
3. Chlorophyll and carotenoid ratios: The chloroplasts of HL-plants possess a higher proportion of chlorophyll a and β-carotene (higher values for the ratios chlorophyll a /b and lower values for a/c and x/c) which reflect the increased level of the chlorophyll a/β-carotene-proteins CPIa, CPI and CPa. The higher level of light-harvesting chlorophyll a/b-xanthophyll-proteins (LHCPs) in LL-plants is also indicated by an increased content of xanthophylls and chlorophyll b as seen from lower a/b and higher x/c and a/c ratios.
4. The results indicate that plants possess the capacity for an ontogenetic adaptation of their photosynthetic apparatus to the incident light intensity. The HL-chloroplasts of HL-plants which contain less antenna chlorophyll, are adapted for a more efficient photosynthetic quantum conversion at light saturation than the LL-chloroplasts with high grana stacks. The correlation between higher levels of light-harvesting chlorophyll a/b-proteins (LHCPs) and a higher stacking degree of thylakoids, and the involvement of LHCPs in stacking is discussed.
Phosphorylation of Ca2+-ATPase by Inorganic Phosphate in Water-Organic Solvent Media: Dielectric Constant and Solvent Hydrophobicity Contribution
Authors: Otero Angela de Souza , Meis Leopoldo de 
Published: August 2018

Abstract
The effect of organic solvents on the phosphorylation of the Ca2+-dependent ATPase of sarcoplasmic reticulum by inorganic phosphate in the absence of a calcium gradient was investigated. Kinetic analysis of the reaction in water and water-organic solvent media according to a bireactant scheme shows no correlation between changes in kinetic parameters and the dieletric constant of the mixed solvents. The pronounced increase in equilibrium levels of phosphoenzyme in water-solvent mixtures is attributed to changes in the water activity of the medium.
Notizen: Hyperglycemia in the Fresh Water Field Crab (Oziotelphusa senex senex) Produced by a Pesticide (BHC)
Authors: Reddy P. Sreenivasula , Babu S. B. Ramesh , Ramamurthi R. 
Published: August 2018

Abstract
Hyperglycemia, Oziotelphusa senex senex, Hyperglycemic Hormone, Hexachlorocyclohexane (BHC) Benzene hexachloride (1,2,3,4,5,6-hexachlorocyclohe-xane) (BHC) produced a significant increase in the hemolymph sugar level of intact crabs. Oziotelphusa senex senex, apparantly by triggering release of the hypergly­ cemic hormone (HGH).
Notizen: A New Method to Prepare Membrane Fractions Containing Ionophore-Stimulated ATPase from Pumpkin Hypocotyls (Cucurbita maxima, L .)
Authors: Scherer Günther F. E. 
Published: August 2018

Abstract
In membrane fractions from pumpkin hypocotyls AT­Pase activity was stimulated by a combination of CCCP (carbonyl cyanide m-chlorophenylhydrazone), a protonophore, and valinomycin, a K+-ionophore. Singly, these ionophores stimulated ATPase activity much less. Nigericin, an H+/K+-antiporter, and nystatin, a cation pore, had similar effects as the combination of CCCP and valinomycin. The results suggest the presence of a cation-translocating ATPase which is stimulated by ionophores by dissipating cation gradients formed in the vesicles. A major part of the ionophore-stimulated ATPase activity correlated with marker enzymes for plasma membranes but part of it could be located in other compartments.