bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorylation of Coformycin and 2′ -Deoxycoformycin, and Substrate and Inhibitor Properties of the Nucleosides and Nucleotides in Several Enzyme Systems
Authors: Bzowska Agnieszka , Lassota Piotr , Shugara David 
Published: August 2018

Abstract
Under conditions where 2′-deoxycoformycin is enzymatically phosphorylated by wheat shoot phosphotransferase to the 5′-phosphate in 15 - 20% yield, coformycin is a relatively poor substrate, and is phosphorylated only to the extent of ≤ 5%. However, chemical phosphorylation of coformycin by modifications of the Yoshikawa procedure led to isolation of coformycin-5′-phosphate in 20% overall yield.
Coformycin-5′-phosphate was characterized by various criteria, including 1H NMR spectroscopy. Comparison of the spectrum with that of the parent nucleoside indicated that the nucleotide is predominantly, although not exclusively, in the conformation anti about the glycosidic bond.
Like 2′-deoxycoformycin-5′-phosphate, coformycin-5′-phosphate was a feeble substrate of snake venom 5′-nucleotidase, and is hydrolyzed, quantitatively, at only 2% the rate for 5′-AMP. With 5′-AMP analogues as substrate, the 5′-phosphates of both coformycin and deoxycoformycin were poor inhibitors of the enzyme, with Ki values > 0.3 mᴍ.
The 5′-phosphates of both coformycin and deoxycoformycin do not significantly inhibit adenosine deaminase (Ki > 0.2 mᴍ), but are potent inhibitors of adenylate deaminase {Ki ≤ 10−9 ᴍ). Neither coformycin nor deoxycoformycin are inhibitors of mammalian purine nucleoside phosphorylase.
The stabilities of coformycin, deoxycoformycin, and their 5′-phosphates, have been examined as a function of pH, and nature of the buffer medium. In particular, all exhibit instability in acid and neutral media, but are relatively stable in the vicinity of pH 9. Some biological aspects of the overall results are presented.
Stereospecific Synthesis by the Sodium Salt Glycosylation Method of Halogeno Benzimidazole 2′ -Deoxyribose Analogues of the Inhibitor of hnRNA Synthesis, 5,6-Dichloro-1-(β-ᴅ-ribofuranosyl)benzimidazole (DRB)
Authors: Kazimierczuk Z. , Stolarski R. , Shugar D . 
Published: August 2018

Abstract
The recently developed stereospecific sodium salt glycosylation procedure has been successfully applied to the synthesis of the β-ᴅ-2′-deoxyribofuranosides of benzimidazole, 5,6-dihalogeno benzimidazoles, and some 2-substituted analogues in high yield. The 5,6-dibromo analogue was obtained by bromination of the parent nucleoside. These have all been characterized by spectro­scopic methods, including 1H NMR, which permitted analyses of their solution conformations and comparison with those of the corresponding ribofuranosides. Some biological aspects, including preliminary results on cytotoxicity and antiviral activity, are briefly considered.
Biotransformation of Tryptophan to Indole-3-acetic Acid by Xanthomonas campestris pv. campestris
Authors: Robeson David J. , Cook Douglas R. 
Published: August 2018

Abstract
Xanthomonas campestris pv. campestris produced in-dole-3-acetic acid when grown in liquid culture in the presence of certain minimum levels of tryptophan.
Associations of Mitochondria with Desmosome-Like Structures in the Oocytes of Raillietiella aegypti (Pentastomida, Cephalobaenida)
Authors: Riehl Rüdiger , Walldorf Volker 
Published: August 2018

Abstract
The oocytes of the cephalobaenid Pentastomid Rail­lietiella aegypti were studied by electron microscopy. A prominent feature of vitellogenic oocytes are numerous spherical, oval and elongated mitochondria. Some of these are shown with desmosome-like structures. The associations between mitochondria and the desmosome-like structures have always been observed to lie freely in the oocyto-plasm; there are no apparent connections with the oocytous plasma membrane. Possible functional roles of these complexes are evaluated.
Alterations in the Activities of Rabbit Erythrocyte Membrane-Bound Enzymes Induced by Cholesterol Enrichment and Depletion Procedures
Authors: Kamber Elli , Kopeikina-Tsiboukidou Liudmila 
Published: August 2018

The effect of cholesterol enrichment and depletion of rabbit erythrocytes on the activities of membrane-bound enzymes, namely (Na+ ,K+)-stimulated ATPase. NAD+ ase and acetylcholinesterase was examined.
The cholesterol content of erythrocyte membranes has been modified by incubation of intact cells with sonicated egg lecithin/cholesterol vesicles (cholesterol/phospholipid molar ratio approx. 2) and with egg lecithin vesicles for time intervals up to 10 hours. The cholesterol/phospholipid molar ratio (CH /PL) of untreated rabbit red blood cell membranes was 0 .92-0.94. Linear increase (up to CH/PL molar ratio 1.72-1.9) or decrease (up to CH/PL molar ratio 0.27 - 0.43) in cholesterol content of erythrocyte membranes was observed over the 10 hours of incubation with egg lecithin/cholesterol and egg lecithin liposomes respectively. Fusion of liposom es to the m em brane or their attachment to the membrane surface was not a significant factor in the alteration of CH/PL ratio. (N+,K+ )-stimulated ATPase, NAD+ ase and acetylcholinesterase activities were measured as a function of membrane cholesterol. The specific activities of all three enzymes were progressively decreased with increase in cholesterol content. Partial reversibility of the inhibitory effect of cholesterol was demonstrated by measurements on cells depleted again after cholesterol enrichment. This was confirmed by the fact that a lowering in cholesterol content evoked an analogous activation of enzymes. The possible implications of physicochemical modifications of bulk and annular lipids of membrane-bound enzymes in the inhibition mechanism are discussed.
Use of Immunotitration to Demonstrate Phytochrome-Mediated Synthesis de novo of Chalcone Synthase and Phenylalanine Ammonia Lyase in Mustard Seedling Cotyledons
Authors: Brödenfeldt Reiner , Mohr Hans 
Published: August 2018

Abstract
The suggestion [H. J. Newbury and H. Smith, Eur. J. Biochem. 117, 575-580 (1981)] of a posttranslational activation of accumulated enzyme precursor by phytochrome was tested in the case of phytochrome-mediated induction of chalcone synthase (EC 2.3.1.74) in mustard seedlings. The approach of immunotitration of enzyme activity was adopted since it allows to relate the amount of antigenic material present in a particular extract to the extract’s enzymatic activity. The data obtained show that under all experimental conditions enzyme activity of an extract is proportional to the amount of im munoresponsive material. No indication was found either of lightdependent modification of the enzyme or of enzymatically inactive immunoresponsive material in extracts prepared from dark-grown mustard seedlings or from light-treated seedlings placed again in darkness. In model experiments with purified ribulose-bisphosphate carboxylase (EC 4.1.1.39) heat-inactivated enzyme was detected by the antibodies. Experiments on induction of phenylalanine ammonia lyase (EC 4.3.1.5) by phytochrome in mustard cotyledons support the result - synthesis de novo of enzyme protein - obtained previously [W. Tong and P. Schöpfer, Proc. Nat. Acad. Sci. U.S.A. 43, 4017-4021 (1976)] with the technique of density labelling. It is concluded that the phytochrome-mediated induction of enzymes involved in anthocyanin formation in mustard cotyledons is due to synthesis de novo of enzyme protein.
Basalflecke und Fleckenlosigkeit in Mohnblüten: Eine chemogenetische Charakterisierung / Basal Blotches and Blotchlessness of Poppy Flowers: A Chemogenetic Characterization
Authors: Böhm H. 
Published: August 2018

Abstract
While Papaver bracteatum and P. pseudo-orientale exhibit large basal blotches in red flowers, these marks are absent in the flowers of their close relative P. orientale. Crossing of the latter species with the former ones surprisingly resulted in hybrids showing blotchlessness. In contrast, the hybrid derived from the interspecific cross P. sommniferum x P. orientale forms relatively small but distinct basal blotches. The first parent has marked, white flowers and another basic number of the genome (x = 11) than P. orientale and its relatives have (x = 7).
Chromatographic analysis confirm ed that pelargonidin and cyanidin are the anthocyanidins of poppy flowers. Basal blotches differ from the other parts of petals since they exclusively contain cyanidin glycosides. If they are absent, pelargonidin glycosides homogeneously colour the petals.
It is concluded that in blotchless flowers of P. orientale and its hybrids the gene responsible for the 3′-hydroxylation of C15 molecules is repressed. This situation is obviously restricted to the basal areas of petals.
Phytoalexin Production by Isolated Soybean Protoplasts
Authors: Mieth Hannelore , Speth Volker , Ebel Jürgen 
Published: August 2018

Abstract
Protoplasts isolated enzymatically from suspension-cultured cells of soybean (Glycine max L. Merr., cv. Harosoy 63) were used to study the production of the isoflavonoid-derived phytoale­xin, glyceollin. A large enhancement in the in vivo rates of synthesis and catalytic activities of two of the enzymes associated with glyceollin biosynthesis, phenylalanine ammonia-lyase and chalcone synthase, preceded phytoalexin accumulation during early stages of culture of isolated protoplasts while cell wall regeneration occurred. A glucan elicitor from cell walls of the fungus Phytophthora megasperm a f. sp. glycinea, an effective inducer of the phytoalexin response in cultured cells, was not capable of enhancing phytoalexin formation in protoplasts. Lack of respon­siveness of the protoplasts to the glucan elicitor could either be associated with their stressed metabolic state in which the response system is already saturated or with the removal from cultured cells of an essential factor of the glucan elicitor-mediated phytoalexin induction during protoplast isolation. At least two components of the protoplast isolation medium, the osmoticum and the fungal endopolygalacturonase, have the potential to initiate the observed phytoalexin synthesis during protoplast isolation. Our results indicate that under the methods employed isolated soybean protoplasts display a stress response which other types of soybean cells show following microbial attack or treatment with elicitor.
Minimal Time Requirement for Lasting Elicitor Effects in Cultured Parsley Cells
Authors: Strasser Heiner , Matern Ulrich 
Published: August 2018

Abstract
Elicitor preparations derived from cell walls of phytopathogenic Alternaria spp. rapidly inhibited uptake of both inorganic phosphate and amino acids by cultured parsley cells. The inhibition of phosphate uptake was completely reversed if the elicitor was removed within a time period of approximately 20 min following its addition to the cell cultures. Cells which had been exposed to the elicitor for more than 20 min prior to washing, however, exhibited an increasingly reduced rate of phosphate uptake as compared to non-induced controls. Maximal inhibition of phosphate uptake (about 30 to 40% of the controls) required 40 min or more of elicitor treatment. These results confirm that a minimal time of exposure to elicitor of about 20 min is necessary to induce lasting effects in parsley cells. Moreover, the initial inhibition of amino acid uptake into the parsley cells suggests that the elicitor rapidly decharged the plasmalemma potential of the cells.
Flow Cytometric DNA-Analysis of Plant Protoplasts Stained with DAPI
Authors: Ulrich Ingunn , Ulrich Wolfgang 
Published: August 2018

Abstract
prepared from leaves of various higher plants were stained with the specific DNA fluorochrome DAPI and measured with a pulse cytophotometer. DNA distribution curves of protoplasts showed DNA histograms like assays of animal cells stained with the same dye solu­tion. The percentage of fractions of cell populations in G0/G1-, S- and G2 + M-phase of the cell cycle could be calculated. A simple method of protoplasts preparation and of flow cytometric estimation of DAPI stained plant protoplasts is described. This method allows cytogenetic and cytokinetic studies of cells from plant material and may be used for fluorescence activated cell sorting.
The Expression of the Isovitexin 7-O-Xylosylating Gene gX in Silene pratensis and S. dioica is Restricted to the Petals
Authors: Steyns Jan , Brederode Jan v. 
Published: August 2018

The isovitexin-O-glycosylation patterns of rosette leaves, stem leaves and petals of Silene dioica plants were investigated. The 7-O -xylosylation of isovitexin, controlled by gene gX, only occurs in the petals. In the leaves isovitexin is 7-O -galactosylated, which is controlled by gene Xgal. Acyl groups may be linked to either the 7-O- or the 2″-O-substituted sugar; the former only occurs in the leaves, whereas the latter takes place both in leaves and petals. The restriction of the gX controlled enzyme activity and its product to the petals of Silene dioica plants is in complete agreement with previously obtained results (reference [2]) on the expression of g X in the genetic background of the closely related Silene pratensis, into which gX can be introduced by introgressive hybridization.
On the basis of serological enzym e inhibition studies, it is argued that the absence of 7-O-xylosylation in the leaves is not due to post-translational inactivation of the gX controlled enzyme. The regulation of the expression of gene gX throughout ontogeny therefore differs markedly from that of two allelic g locus variants, controlling the 7-O-glucosylation of isovitexin.
Colletruncoic Acid Methyl Ester, a Unique Meroterpenoid from Colletotrichum truncatum
Authors: Stoessl Albert , Stothers J. B. 
Published: August 2018

Abstract
Metabolites isolated from the soybean pathogen Colletotrichum truncatum were identified as meso- and ᴅ-( -)-butane-2,3-diol and the previously unreported compound , colletruncoic acid methyl ester, to which structure 1 is assigned mainly on 1H - and 13CMR evidence. The compound has a skeleton unprecedented for a fungal polyketide. The previously unknown 2-hydroxymethylhexa-2,4-dienol was also isolated.
6-(Hydroxythio) carbonyIpyridin-2-carbonsäure und Pyridin-2-carbon- säure-6-monothiocarbonsäure als biosynthetische Zwischenstufen bei der Bildung von Pyridin-2,6-di(monothiocarbonsäure) aus Pyridin-2,6- dicarbonsäure [1] / 6-(Hydroxythio)carbonylpyridine-2-carboxylic Acid and Pyridine-2-carboxylic Acid-6- monothiocarboxylic Acid as Interm ediates in the Biosynthesis of Pyridine-2,6-di(monothiocarboxylic Acid) from Pyridine-2,6-dicarboxylic Acid [1]
Authors: Hildebrand U. , Taraz K. , Budzikiewicz H. 
Published: August 2018

Abstract
It is shown by feeding experiments with [3-2H]pyridine-2,6 -dicarboxylic acid that 6 -(hydroxythio)carbonylpyridine-2-carboxylic acid and pyridine-2 -carboxylic acid-6-m onothiocarboxylic acid are intermediates in the biosynthesis of pyridine-2,6 -di(monothiocarboxylic acid) from pyridine-2,6 -dicarboxylic acid produced by Pseudomonas putida. Thus the series of biosynthetic steps - COOH → - CO - SOH → COSH has been demonstrated for the first time.
Species-Specific Differences in Acetyl Coenzyme A Synthesis of Chloroplasts
Authors: Treede Hans-Jürgen , Riens Burgi , Heise Klaus-Peter 
Published: August 2018

Abstract
Acetyl-CoA and Fatty Acid Synthesis, Chloroplasts The present investigation indicates that photosynthetically active chloroplasts can synthesize acetyl-CoA either from acetate via acetyl-CoA synthetase (ACS) or from pyruvate via the pyru­ vate dehydrogenase complex (PDC). Both enzyme systems have been assayed in rapidly prepared extracts of chloroplasts isolated from spinach, peas and maize mesophyll. Their kinetic properties showed few species-specific differences. The differing pyruvate and acetate concentrations within the corresponding leaf tissues have been interpreted, therefore, as constituting a major factor determining the relative involvement of both acetyl-CoA synthesizing systems within the different types of chloroplasts. The idea that acetate originates from mitochondria and pyruvate from the cytosol has been supported by nonaqueous fractionation studies. Diffusion-mediated faster up­ take of acetate may indicate a predominant role of the ACS in spinach chloroplasts. Higher cellular pyruvate/acetate-ratios (2-5) in pea and maize leaves may enhance pyruvate uptake into chloroplasts and thus PDC-driven acetyl-CoA synthesis in pea and maize mesophyll chloroplasts. Maize mesophyll chloroplasts even show a light-driven pyruvate uptake accompanied by a stimulated acetyl-CoA and fatty acid formation. Assuming light-dependent increasing parameters in the stroma space, like Mg2+-concentrations, pH and ATP, as further control criteria in chloroplast acetyl-CoA formation, the ACS appears better adapted to the circumstances in illuminated chloroplasts because of the fact that 1. the ACS requires these cofactors altogether; 2. the PDC is stimulated by increasing pH (up to 8) and Mg-levels (up to 5 mᴍ) alone.
Acyclo Nucleosides and Nucleotides: Synthesis, Conformation and Other Properties, and Behaviour in Some Enzyme Systems, of 2′,3′-Seco Purine Nucleosides, Nucleotides and 3′:5′-Cyclic Phosphates, Analogues of cAMP and cGMP
Authors: Stolarski Ryszard , Kazimierczuk Zygmunt , Lassota Piotr , Shugar David 
Published: August 2018

Abstract
The 3′:5′-cyclic phosphates of 2′,3′-secoadenosine and guanosine, structural analogues of cAMP and cGMP, were synthesized by cyclization of the 5′-phosphates of 2′,3′-secoadenosine and guanosine, respectively. The 2′,3′-seco-3′:5′-cAMP was converted to the IM P analogue by nitrous acid deamination, and to the 8-bromo analogue by bromination.
Chemical phosphorylation of 2′,3′-secoadenosine gave four products, the major one of which, in 50% yield, was 2′,3′-seco-3′:5′-cAMP, identical to that obtained by the cyclization reaction above. The three other products have been tentatively identified.
The conformations in solution of the seco nucleosides, their 5′-monophosphates, and their 3′:5′-cyclic phosphates, were determined with the aid of 1H , 13C and 31P NMR spectroscopy, particular attention being devoted to orientations about the C-O bonds and the glycosidic bond, and the results compared with crystallographic data available for the 2′,3′-seco congener of ribofuranosyl benzimidazole. The findings are briefly discussed in relation to substrate and inhibitor properties in some enzyme systems.
Some of the foregoing compounds have been examined as potential enzyme substrates and inhibitors. In particular, the seco 3′:5′-cyclic phosphates are resistant to cAMP cyclic phos­ phodiesterase of mammalian origin, but are slowly hydrolyzed by purified higher plant cyclic nucleotide phosphodiesterase to the corresponding monophosphates.
Effect of Tuftsin on the Phagocytotic Activity of the Unicellular Tetrahymena. Does Primary Interaction Develop Imprinting ?
Authors: Csaba G. , László Valéria , Kovács P. 
Published: August 2018

Abstract
The natural mammalian phagocytosis stimulator tetrapeptide tuftsin stimulated also the phagocytosis of the unicellular Tetrahymena. The selectivity of the Tetrahymena was not complete, as threonin-free tuftsin provoked a greater response. Treatment with tuftsin did not develop functional imprinting, however the binding capacity of cell membrane significantly increased after the first treatment.
The Photosynthetic Apparatus of Ectothiorhodospira halochloris 3. Effect of Proteolytic Digestion on the Photoactivity
Authors: Steiner R. , Kalumenos B. , Scheer H. 
Published: August 2018

Abstract
Photsynthetic membranes of Rhodopseudomonas virids and Ectothiorhodospira halochloris were treated with proteinase K. The photochemical activity (light minus dark difference spectra) were compared to the polypeptide composition (SDS-polyacrylamide gel analysis). In E. halo­chloris, difference bands appear at 806 (+), 838 (+) and 854 nm (-) . All three decrease in intensity upon incubation with proteinase K., but this decrease is much slower than the proteolysis of both the reaction center and antenna related polypeptides. Photochemical activity remains high as long as a small part of the RC and two lower molecular weight polypeptides M* (22.0 kDa) and B* (15.3 kDa) are present. The M subunit is the most stable polypeptide in the RC of Rp. viridis too, and the photochemical activity is related to the remainder of this and to the one newly formed polypeptide (15.3 kDa), but doesn’t show the typical absorption shift of the antenna (B 800/1020 → B 800/960). The results are discussed quantitatively and compared to those obtained from Bchl α containing organisms.
Interaction of Sodium, Lithium, Caesium, and Potassium Ions with Ascorbyl Radicals
Authors: Wieczorek Piotr , Ogoński Tadeusz , Machoy Zygmunt 
Published: August 2018

Abstract
The influence of the concentration of sodium, lithium , caesium, and potassium ions as well as of the ionic strength of the solutions used on the dismutation rate of ascorbyl radicals has been investigated. While the dismutation rate was not influenced by Li+, it decreased, however, with increasing concentrations of the other ions investigated. The largest effect was obtained with Na+. This change in dismutation rate indicates a stabilizing effect on ascorbyl radical by these ions.
The Effect of Phosphinothricin (Glufosinate) on Photosynthesis II. The Causes of Inhibition of Photosynthesis
Authors: Sauer Heidrun , Wild Aloysius , Rühle Wolfgang 
Published: August 2018

It was shown in the previous study that phosphinothricin (glufosinate) causes an accumulation of ammonia and inhibition of photosynthesis. The extent to which there is a connection between these two processes is now investigated in the present study. First of all. the role of NH3 per se in the impairment of photosynthesis was to be clarified. For this purpose, the inhibition of photosyn­thesis was investigated in relation to exogenously applied ammonia in chloroplasts, protoplasts and entire leaves. The comparison with the experimental results in leaves in which the ammonia was formed endogenously (by action of phosphinothricin) shows that the ammonia toxicity at least cannot be solely responsible for the inhibition of photosynthesis. This is confirmed by the finding that photosynthesis is maintained under non-photorespiratory conditions, although considerable amounts of NH3 are concentrated at the same time in the plants. A process connected with photorespiration appears to play the essential role.
Simultaneous administration of phosphinothricin and glutamine largely prevented the impair­ment of photosynthesis. This indicates that the main cause for the inhibition of photosynthesis by phosphinothricin is based on a depletion of glutamine. Three subsequent reactions which may cause the inhibition of photosynthesis are discussed: 1) an inhibition of protein biosynthesis, 2) a toxic accumulation of glyoxylate in the photorespiratory cycle and 3) a deficiency of intermediates of the Calvin cycle in consequence of the interrupted photorespiration.
Steric Course of the Rhodium-Catalyzed Decarbonylation of Chiral 4-M ethyl-[1-3H,2-2H1]pentanal
Authors: Otsuka Hideaki , Floss Heinz G. 
Published: August 2018

Abstract
(R)-and S)-4-methyl-[1-3H,2-2H1]pentanal were prepared from l -and D-leucine via leucic acid and (S)-and (R)-4-methyl-[2-2H1]pentanoic acid. Decarbonylation of these samples with tris-(triphenylphosphine)rhodium chloride followed by Kuhn-Roth oxidation of the resulting 2-methylbutane gave chiral acetic acid of 35% e.e. S and 31% e.e. R configuration, respectively. The decarbonylation reaction thus proceeds with net retention of configuration, possibly accom­panied by some racemization.
Epicuticular Wax Hydrocarbons of Ericaceae in Germany
Authors: Salasoo Inno 
Published: August 2018

Abstract
Alkane distribution patterns were determined in the epicuticular wax of 7 species of Ericaceae, including 5 species from more than one location. Results showed good agreement between sam­ples of any given species from different locations; thus any differences in environmental condi­tions including altitude were insufficient to affect the alkane patterns. Average chain length was highest in Calluna vulgaris and lowest in Vaccinium uliginosum.