bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis of Stizolobinic Acid and Stizolobic Acid in the Etiolated Seedlings of Stizolobium hassjoo
Authors: Saito Koshi , Komamine Atsushi , Senoh Siro 
Published: August 2018

Incorporation of ʟ-[U-14C] phenylalanine, ʟ-[U-14C] tyrosine and ᴅʟ-[β-14C] 3,4-dihydroxyphenyl-alanine (DOPA) into stizolobinic acid, ʟ-β-(6-carboxy-α′-pyron-3-yl) -alanine, and stizolobic acid. ʟ-β-(6-carboxy-α′-pyron-4-yl)-alanine, was investigated as test precursors for these new types of amino acids in the epicotyls of etiolated seedlings of Stizolobium hassjoo. Radioactive stizolobinic acid and stizolobic acid resulted from administering labelled precursors were identified by colour reactions, radioautography and/or recrystallization to constant specific radioactivity. Radiolabelled stizolobic acid was subjected to alkaline hydrolysis and distribution pattern of the radioactivity was further examined in a degradation fragment of the amino acid.
Proposed biosynthetic routes to stizolobinic or stizolobic acid from DOPA were empirically con­ firmed and the results are further discussed in relation to the possibility that phenylalanine may also be introduced into reaction sequences leading to the synthesis of both heterocyclic amino acids.
Further Studies on the Biosynthesis of Stizolobinic Acid and Stizolobic Acid in the Etiolated Seedlings of Stizolobium hassjoo
Authors: Saito Koshi , Komamine Atsushi , Senoh Siro 
Published: August 2018

Abstract
Incorporation of doubly labelled tyrosine into stizolobinic acid and stizolobic acid by the etiolated seedlings of Stizolobium hassjoo was studied. The retention of tritium activity in stizolobinic acid was 55%, while that in stizolobic acid was only 4.4% in average. The results strongly suggest that the heterocyclic rings of these two amino acids may be derived from 3,4-dihydroxyphenyl-alanine (DOPA) by extradiol cleavage of the aromatic ring.
Heterogeneity in Chloroplasts of Siphonacious Algae as Compared with Higher Plant Chloroplasts
Authors: Lüttke Angela , Rahmsdorf Ursula , Schmid Rainer 
Published: August 2018

Abstract
The chloroplast population of Acetabularia contains four subpopulations of intact plastids with the buoyant densities at 1.21 g/cm3 - 1.18 g/cm3 - 1.14 g/cm3 - 1.10 g/cm3 on the discontinuous sucrose gradient. The starch content varies with the buoyant densities. The subpopulations probably represent entities of different biochemical function.
Ribose Conformations of 8-Azapurine Nucleosides in Solution
Authors: Lüdemann H.-D. , Westhof E. , Cuno I. 
Published: August 2018

Abstract
The ribose conformations of 8-azaadenosine, 8-azaguanosine, and 8-azainosine have been studied using proton magnetic resonance in ND3 solutions, in D2O solutions, and in pyridine solutions. The temperature was varied between - 60 and + 40 ° C in ND3 and between + 10 and + 60 °C in D2O solutions. The analysis is based on the two state S ⇌ N model of the ribose moiety proposed by Altona and Sundaralingam. In D2O, the 8-aza substitution destabilizes the gg rotamer and simultaneously diminishes the population of the S state of the ribose. It is deduced that the anti population of the base is greater in the 8-azapurine (β) ribosides than in the common purine (β) -ribosides.
Photo-Induced Electron Transfer in Chlorophyll Containing Liposomes
Authors: Oettmeier Walter , Norris James R. , Katz Joseph J. 
Published: August 2018

Abstract
Liposomes (lipid, ᴅʟ-α-dipalmitoyl-phosphatidylcholine) containing chlorophyll a (ratio lipid to chlorophyll 30:1) exhibit an absorption maximum at 670 nm. Upon oxidation with iodine these liposomes yield a chlorophyll radical that shows a ESR signal with a line width (peak to peak) ⊿Y = ~0.1 G and a g-value of 2.0022, consistent with the presence of monomeric chlorophyll. Under anaerobic conditions, in the absence of acceptors, no light induced ESR signal is observed, whereas under aerobic conditions the chlorophyll free radical is generated in the light. Acceptors having access to the lipid membrane, like Fe3+ -pyrophosphate and methylviologen, give rise to chlorophyll radical formation, or, like quinones, form a semiquinone radical in the light. Non-permeable acceptors, such as ferricyanide, NADP, FMN and cytochrome c do not act as acceptors and no chlorophyll radicals can be produced by light. Furthermore, light dependent and completely reversible electron transfer from N,N,N′,N′-tetramethyl-p-phenylenediamine to ubiquinone can be demonstrated. Liposomes containing chlorophyll, therefore, can serve as a model system for photosynthetic electron transport.
Coa/Coß-Isom erie der Corrinoide. Partialsynthese und Escherichia coli -Aktivität weiterer Isomerenpaare der (Co-M ethyl)-corrinoide Coa/Co/Msomerism of Corrinoids. Partial Synthesis and Escherichia coli Activity of Further Isomer Pairs o f the (Co-methyl)-Corrinoids
Authors: Moskophidis M , Maria Klotz Christa , Friedrich W , Errn H. , Moskophidis M. , Kühnau  , Klotz Christa Maria , Friedrich W. 
Published: August 2018

Abstract
Vitamin B 12 , Methylcorrinoids, Coα/Coβ-isomerism, E. coli Activity In 2-methyladenyl-(Coβ-methyI) -cobamide and in adenyl-(Coβ-methyl)-cobamide the nucleotide base is coordinated to the cobalt atom in neutral and weak acidic aqueous solutions (in the cor­ responding adenosylcorrinoids the nucleotide base is not coordinated). 2-Methylthioadenyl-(Coβ-methyl)-cobamide resembles, with regard to the coordination of the nucleotide base, the benz-imidazole-corrinoids.
The partial synthesis via cobalt (I) corrinoids results in a variable proportion: (Coα-methyl) iso­ mer/(Coβ-methyl) isomer, e .g . 7/93 (cobalamin) and 50/50 (p-cresylcobamide). This proportion is generally low, if in the corresponding cyanocorrinoid the nucleotide base is firmly coordinated; it is high, if the coordination in the corresponding cyanocorrinoid is weak or absent. These results are compatible with the assumption that in the cobalt (I) corrinoids the nucleotide base is to a certain extent coordinated.
In Escherichia coli 113-3 the examined (Coα-methyl)-corrinoids show a weaker bioactivity than the corresponding (Coβ-methyl) -corrinoids.
Photosynthetic Electron Carriers at a Heptane-Water Interface
Authors: Brody S. S. , Owens N. F. 
Published: August 2018

Abstract
Surface properties of monomolecular films of chlorophyll (Chi), plastocyanin (Pc), cytochrome c (Cyt) and ferridoxin (Fd) were measured at a heptane-water interface. Mixed films of Chl and the other components were examined in darkness and in light. The area/molecule, A, for Fd (from Cl. pasteurianum) is much larger at a heptane-water than Fd (from spinach) at an air-water interface. This difference in A may be the source of the Fd or the extent of denaturation at the different interfaces. There appears to be a photoreaction between Chil and Fd in the presence of ascorbate. The A for Cyt is much larger at a heptane-water than at an air-water interface. In mixed films there is a strong interaction between Chl and reduced Cyt in the dark. No such interaction is ob­served between Chi and oxidized Cyt. With mixed films of Chi and reduced Pc there is a significant, reversible, light induced change in ΔV.
Chromosomale Strukturen von Pseudomonas testosteroni. II. Aktivität der endogenen RNA-Polymerase /Chromosomal Structure of Pseudomonas testosteroni. II. Activity of the Endogenous RNA-Polymerase
Authors: Reimer Günter , Drahovsky Dusan 
Published: August 2018

Abstract
After careful lysis the nucleoid of Pseudomonas testosteroni can be isolated in three different forms with compact and unfolded DNA structures 1. The released nucleoids contain endogenous DNA-dependent RNA-polymerase activity using the chromosomal DNA as a template. RNA syn­ thesis is proportional to duration of RNA-polymerase reaction and amount of DNA-protein-complexes. The sensitivity towards ionic strength and rifampicin indicates that a part of RNA-polymerase activity is tightly bound to the chromosomal DNA.
β -Diketoester und deren Enoläther als Aminosäure-Antagonisten. On Amino Acid Antagonists: β-Diketoesters and Their Corresponding γ-Enolethers
Authors: Trowitzsch Wolfram , Sahm Hermann 
Published: August 2018

Abstract
Starting with well known β-diketoesters the corresponding y-enolethers are synthesized and described. Both classes of compounds inhibited the growth of some microorganisms. The inhibition is abolishable by addition of certain amino acids to the definite medium. A possible mechanism of inhibition is discussed and compared with the mechanism of some β,γ-unsaturated α-amino acids. The known unsaturated a-amino acids, their origin and their biological activity are summarized in two tables.
Studies on Prototropic Tautomerism in Neutral and Monoanionic Forms of Pyrimidines by Nuclear Magnetic Resonance Spectroscopy
Authors: Stolarski Ryszard , Remin Mieczyslaw , Shugar David 
Published: August 2018

Abstract
NMR methods have been applied to evaluation of prototropic tautomerism, N(1)H ⇌ N (3) H, in several selected pyrimidines, viz. the neutral forms of Isocytosine and 2-alkylthiopyrimidone-4, and the monoanionic forms of uracil, 5-fluorouracil and 4-thiouracil.
The predominant tautomeric species of the neutral forms could be estimated only qualitatively from 1H chemical shifts. For the monoanionic forms this procedure was not applicable, for reasons which are discussed in detail.
For the monoanionic form of uracil, 13C chemical shifts of C(5) provided a suitable criterion for quantitative estimation of the populations of the two known tautomeric species. However, the potential scope of this procedure appears somewhat limited.
By contrast, the values of the vicinal proton-proton coupling constants, J (5,6), provided both necessary and adequate criteria for quantitative evaluation of the tautomer populations for all the neutral and monoanionic forms. The results were in satisfactory agreement with those obtained by optical spectroscopic methods. In some instances the results obtained in this way may be more reliable than those derived from optical methods.
The range of applicability, and utility, of NMR methods to studies on protropic tautomerism in pyrimidines are critically assessed.
Chromophore Content of C-Phycoerythrin from Various Cyanobacteria
Authors: Muckle Günther , Rüdiger Wolf 
Published: August 2018

Abstract
The molar extinction coefficient for phycoerythrobilin (1a) was calculated by two independent methods. It is different from that of the cleaved chromophore, phycobiliviolin (2). By unfolding with urea or tryptic digestion, the chromophore absorption of C-phycoerythrin (PE) was determined free of any protein influence. The chromophore content of PE from various Cyanobacteria was determined with these data to be either 5 or 6, depending on the organism. This corresponds to a chromophore distribution over phycoerythrin subunits α:β of either 2:3 or 2:4. The phylogenetic significance of varying chromophore content is discussed.
A Kinetic Model for Translocators in the Chloroplast Envelope as an Element of Computersimulation of the Dark Reaction of Photosynthesis
Authors: Giersch Christoph 
Published: August 2018

Abstract
A kinetic model for the chloroplast translocators (mediating equal and opposite exchange fluxes between the external medium and the stroma) is derived. This model is a modification of the classical Widdas model corresponding to the exchange of an arbitrary number of compounds with no contribution to net transport. It describes the rate of transport of each compound in simple terms and with a minimum number of kinetic constants. Predictions from the model agree with experimental data as recorded in the literature.
From the experimental apparent kinetic constants VMAX and Km those in terms of the model are calculated. These constants complete the model and make it applicable to the study of metabo­lism of photosynthesis by means of computer simulation. The set of differential equations describing the operation of the phosphate translocator is solved numerically for some illustrative examples.
NOTIZEN / Langkettige Alkane und Alkohole aus den Blattwachsen verschiedener Coffea-Arten / Long Chain Alkanes and Alcohols from the Leaf Waxes of Different Coffea Species
Authors: Stocker Hans , Wanner Hans 
Published: August 2018

Abstract
A gaschromatographic study has been made of the alkane-and alcoholic fractions from the leaf waxes of some Coffea species. The n-alkanes have the odd-carbon-numbered, the primary alcohols the even-carbon-numbered members pre­ dominating. The major homologues of the alkane fractions are C29 and C31 and of the alcoholic fractions C30 and C32 . The sub-divisions Erythrocoffea and Pachycoffea could be distinguished by the alkane patterns. Im Rahmen einer chemotaxonomischen Studie der Gattung Coffea wurden die Alkan-und Alkohol­ fraktionen der Blattwachse untersucht.
Pisatin as a Major Phytoalexin in Laihyrus
Authors: Robeson David J. , Harborne Jeffrey B. 
Published: August 2018

Abstract
The pterocarpan pisatin has been identified as a major phytoalexin in fifteen species of Lathyrus. Thus, the genus is closer in its phytoalexin response to Pisum than to Vicia, which is known to produce furanoacetylenes on fungal in­ vasion.
Properties of an Adenosine Cyclic Phosphates Degrading Enzyme in Nicotiana tabacum L. var. Xanthi
Authors: Brennicke Axel , Frey Hans Dieter 
Published: August 2018

Abstract
This work describes an enzyme which degrades adenosine 3′:5′-cyclic phosphate (3′ :5′-cyclic-AMP) and adenosine 2′:3′-cyclic phosphate (2′:3′-cyclic-AMP). The reaction pro­ ducts are 3′-AMP and 5′-AMP in case of 3′:5′-cyclic-AMP, 2′-AMP and 3′-AMP when 2′:3′-cyclic-AMP is given as substrate. Inorganic phosphate acts as a strong inhibitor, whereas theophyllin does not act up to a concentration of 10-3 m . Probably the adenosine cyclic phosphates degrading enzyme has no function in a ‘second messenger’ system with 3′:5′-cyclic-AMP.
Notizen: Weak and Strong Phase Shifting in the Activity Rhythm of Leucophaea maderae (Blaberidae)after Light Pulses of High Intensity
Authors: Wiedenmann Gottfried 
Published: August 2018

Abstract
In the running activity of the cockroach Leucophaea maderae a strong phase response curve is found when using high intensity light pulses (80 000 lx and about 12 hours duration). The phase response curve has an unsymmetric shape: delays are larger than advances. The phase jump lies about 2 hours after subjective midnight.
Biochemie der Metallocene, II Organ-Verteilung und Thymus-Anreicherung von [103Ru]Cinnamoyl-ruthenocen / Biochemistry of Metallocenes, II. Organ-Distribution and Thymus Affinity of Cinnamoyl-[103Ru] Ruthenocene
Authors: Wenzel M. , Herken R. , Klose W. 
Published: August 2018

Abstract
Metallocenes, labelled with 103Ru, are potential radiopharmaceuticals for use in nuclear medicine diagnosis. Ruthenocene derivatives with oxopropene side-chains were administered to mice and rats to study their biochemical properties. Excretion rates and organ distributions of 103RuCl3 and Cinnamoyl-[103Ru] ruthenocene were very different. While 103RuCl3 was relatively evenly distributed in the body, the metallocene derivative was concentrated in liver, lungs and spleen after intravenous (i.v.) injection. After i.p. injection however a high thymus affinity was observed and autoradiography proved that the site of 103Ru accumulation was in thymocytes. The thymus affinity can be diminished by corticoid pretreatment and raised by inhibition of phagocytosis (BeSO4). The mechanism of accumulation in the thymus and a possible clinical application are discussed.
Nonenzymatic Transformation of Riboflavin into 5,6-Dimethylbenzimidazole
Authors: Renz Paul , Wurm Rainer , Hörig Joachim 
Published: August 2018

Riboflavin, the biosynthetic precursor of the 5,6-dimethylbenzimidazole moiety of vitamin B12, is transformed non-enzymatically into 5,6-dimethylbenzimidazole in small yield on treatment with 1 ɴ or 5 ɴ NaOH at 100 °C. Besides 5,6-dimethylbenzimidazole 1,2-diamino-4,5-dimethylbenzene, 1.2- dihydro-6,7-dimethyl-2-keto-1-ᴅ-ribityl-3-quinoxaline carboxylic acid and N-1-ᴅ-ribitylamino-2- amino-4,5-dimethylbenzene can be detected. When [1′-14C] riboflavin is used the 5,6-dimethyl­benzimidazole contains about 75 per cent of the specific radioactivity of riboflavin. N-1-ᴅ-ribityl- amino-2-amino-4,5-dimethylbenzene is transformed into 5,6-dimethylbenzimidazole more efficiently than riboflavin. Oxygen enhances the yield of 5,6-dimethylbenzimidazole and 1,2-diamino-4,5-di- methylbenzene from riboflavin as well as from N-1-ᴅ-ribitylamino-2-amino-4,5-dimethylbenzene. 1.2- diamino-4,5-dimethylbenzene reacts together with formaldehyde but not with formate to form 5,6-dimethylbenzimidazole under alkaline conditions at 100 °C.
It is therefore suggested that the nonenzymatic reaction of riboflavin proceeds via N-1-ᴅ-ribityl- amino-2-amino-4,5-dimethylbenzene and 1,2-diamino-4,5-dimethylbenzene, and that the latter reacts with formaldehyde preferably formed by oxidative degradation of C-1′ of the ribityl side chain to form 5,6-dimethylbenzimidazole via its unstable imidazoline derivative. The possible relevance of these results for the enzymatic process is discussed.
Sucrose Gradient Analysis: Computer Simulation and Measurement of the Parameters Involved in the Sedimentation of DNA Molecules
Authors: Macchiato M. F. , Grossi G. F. , Gialanella G. C. , Cascino A. 
Published: August 2018

The Montecarlo method is used to computer simulate a random distribution of molecular lengths generated by inducing T4 DNA fragmentation through the decay of 32P atoms introduced in the molecule.
Taking into account the experimental conditions we find that the value of α for alkali sucrose gradients is 0.46 + 0.02 and does not depend on the running time. Our findings also prove that the computer simulation can be utilized to analyze sedimentation profiles of DNA molecules fragmented in vivo.
On Domain Structure and Local Curvature in Lipid Bilayers and Biological Membranes
Authors: Gebhardt C. , Gruler H. , Sackmann E. 
Published: August 2018

Abstract
The lateral lipid organization and the local surface curvature in small and giant bilayer vesicles of binary lipid mixtures were investigated. Mixtures of the following lipids are studied: Cholesterin, di-alcyl-lecithins, dioleyl-lecithin and di-alcyl-phosphatidic acid. The latter is considered as being representative of charged natural lipids (e.g. phosphatidyl serine or cardiolipin).
Three different experimental methods are compared: 1) The excimerfluorescence method, 2) the spin label technique and 3) the freeze fracture electron microscopy. The latter two methods yield information on the size of lipid precipitations. The surface curvature may be studied by electron microscopy. The essential experimental results are: (1) Mixtures of smectic phases of different symmetry undergo lateral phase separation. (2) The phase separation leads to a domain-like lateral lipid organization. (3) The domain structure is often accompanied by a variation in local curvature. (4) In membranes containing a charged lipid component, the domain structure may also be triggered by external charges (such as surface proteins). (5) two types of domains are observed: Circular domains (diameters of the order of several 100 Å) occur in mixtures of non-tilted fluid and rigid phases. Elongated domains (width ∼ 100 Å) are observed in mixtures of tilted and nontilted phases. This domain pattern is characteristic for mixtures of lecithins and cholesterols.
The domain structure is explained by combining the theory of spinodal decomposition of alloys with the essential result of the orientational elastic model of membranes. The domain size calculated from this model agrees well with the experimental result. The periodic ripple structure observed between the pre-and the main transition is explained by generalizing the concept of spinodal decomposition to include the separation of phases which are only distinguishable (e. g. by the tilt angle). The width of the domains in equilibrium is explained in terms of the spontaneous curvature of the decoupled monolayer of a bilayer. Good agreement with the experimental result is obtained. The ripple phase is only a special case of the surface induced domain structures in ordinary liquid crystals. The defect structure of the ripple phase has been analysed in terms of its symmetry. A symmetry rule is established which leads to a model of lipid orientation.
Below the pretransition no periodic domain pattern is observed under normal conditions. But upon cooling a bilayer very rapidly a defect structure reminiscent of a screw dislocation is ob­ served. This is expected for coupled biaxial monolayers.
Studies on the Helical Structure of β-ᴅ-1,3 Xylan
Authors: Haleem M. Abdul , Parker K. D. 
Published: August 2018

Abstract
The structure of β-ᴅ-1,3 xylan has been studied in detail. Atomic coordinates in the unit cell are determined. A method for calculating structure factors for the triple helical structure of β-ᴅ-1,3 xylan which is suitable for com puter and which avoids Bessel function is described. The structure is further refined by least square method. The R-value and Φ-value are minimized at 0.41 and 4.417.
Composition of the Ventral Gland-Pad Sebum from the Mongolian Gerbil, Meriones unguiculatus
Authors: Jacob Jürgen , Green Uwe 
Published: August 2018

Abstract
The chemical composition of the gland-pad sebum of gerbils of both sexes is analysed using gas-liquid chromatographical and mass spectroscopical techniques and compared with the lipids from distal skin areas. Cholesterol esters, with (ω-1)-methyl-substituted fatty acids as acidic constituents, were shown to occur in the gland-pad sebum of both sexes in high concentrations, whereas cholesta-3,5-diene could be detected in the males only.
Acid/Base-Induced Exchange of Adenine Nucleotides on Chloroplast Coupling Factor (CF1)
Authors: Huchzermeyer Bernhard , Strotmann Heinrich 
Published: August 2018

Abstract
Exchange of CF1-bound adenine nucleotides was shown to take place when isolated broken chloroplasts were subjected to an acid/base treatment. This process was measured in forward (in­ corporation of 14C-labeled nucleotides) as well as back exchange reactions (release of bound labeled nucleotides). In the presence of unlabeled ADP and Pi a high precentage of labeled ATP was found to be released into the medium.
Exchange is highly specific for exogenous ADP and ATP. Acid/base-induced adenylate exchange and acid/base-induced phosphorylation were measured in dependence of several external factors. The substrate constant for ADP in exchange was 1.6 μм, whereas an apparent Km of 5 μм was determined for ADP in the phosphorylation process.
Acid/base-induced exchange of adenine nucleotides and acid/base-induced phosphorylation depend in a similar way on the pH values of the acid and base stages.
Acid/base-induced ATP formation was sensitive to prolonged treatment in the acid stage whereas exchange was not. Mg2+ was strictly required in phosphorylation but less important in exchange. The phosphorylation ability decreased within seconds after acid/base transition; however, the ability of [14C]ADP incorporation persisted for minutes. The formation of ATP depended on an acid/base transition, whereas some adenylate exchange was also induced by an acid treatment alone.
The results suggest that appropriate pH values at the inner and outer side of the thylakoid membrane rather than energy from a pH gradient is sufficient for adenylate exchange to take place on membrane-bound CF1.
Isolation of the Major Glycoprotein (gp70) of Simian Sarcoma Virus (SSV-1/SSAV-1) in Preparative Quantities
Authors: Thiel H.-J. , Bergholz C. , Beug H. , Deinhardt F. , Schwarz H. , Schäfer W. 
Published: August 2018

Abstract
The major glycoprotein (gp70) of simian sarcoma virus is present in “soluble” form in the medium of virus-producing suspension cultures. It could be isolated from the supernatant of such cultures in substantial amounts by an immuno-adsorbent technique. Some of its gel-electrophoretic and serological properties are described.