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1991 (171)
81Author    Sn Bakalova, L. Biczók, T. BércesRequires cookie*
 Title    Photophysical and Photochemical Properties of 2,3-Dihydro-4(l H)- quinolinones. Part II. Rates and Mechanism of Primary Processes  
 Abstract    Fluorescence quantum yields, singlet lifetimes and triplet yields for 2-methyl-2,3-dihydro-4(1 H)-quinolinone and N -m ethyl-2,3-dihydro-4(l H)-quinolinone were determined as a func­ tion o f temperature. In non-polar solvents, an efficient non-radiative process identified as an indirect singlet —* • triplet transition occurring through S2(n,jr*) was found to depopulate the lowest S 1(7t,7E*) state. In polar solvents, direct singlet —> triplet intersystem crossing appears to dominate. Photochemical dehydrogenation produced the corresponding 4(1 H)-quinolinone with a yield o f few times 10"2. This was shown to be the only traceable reaction route. 
  Reference    Z. Naturforsch. 46c, 549 (1991); received March 16/A pril4 1991 
  Published    1991 
  Keywords    Dihydroquinolinones, Triplet Yields, Fluorescence Quantum Yields, Photochemical D ehy­ drogenation, Singlet Lifetimes 
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 Identifier    ZNC-1991-46c-0549 
 Volume    46 
82Author    A. TrebstRequires cookie*
 Title    A Contact Site between the Two Reaction Center Polypeptides of Photosystem II Is Involved in Photoinhibition  
 Abstract    D edicated to Professor W olfgang H aupt on the occasion o f his 70th birthday D 1 polypeptide, Herbicide Binding Site, Photoinhibition, Photosystem II, Plastoquinone A new contact site between the two reaction center polypeptides D 1 and D 2 o f photosystem II close to arg 238 and arg234 respectively is proposed. The amino acid sequences involved are between the 4 th transmembrane and a connecting parallel helix. The sequence includes a tryp­ sin sensitive site in both polypeptides, the likely cleavage site in the rapid turnover o f the D 1 polypeptide and part o f the herbicide binding site. The contact site is oriented towards both quinone binding sites Q A and Q B. A folding o f the backbone o f the amino acid sequences involved is proposed. 
  Reference    Z. Naturforsch. 46c, 557 (1991); received March 6 1991 
  Published    1991 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0557.pdf 
 Identifier    ZNC-1991-46c-0557 
 Volume    46 
83Author    Fumihiko Satoa, YasuyukiY. Am Adaa, Sang Soo, W. Akb, Katsunori Ichinoseb, M. Itsuhiro Kishidab, N. Obutaka Takahashic, Shigeo YoshidabRequires cookie*
 Title    Photoautotrophic Cultured Plant Cells: A Novel System to Survey New Photosynthetic Electron Transport Inhibitors  
 Abstract    The responses o f photoautotrophic (PA) cultured cells o f tobacco (N icotiana tabacum cv. Samsun N N) and liverwort (M archantia polym orpha L.) to thirty-eight cyclohexanedione de­ rivatives were surveyed. Each derivative was also tested for inhibitory activity on photosyn­ thetic electron transport (PET), using isolated thylakoids, and herbicidal activity, using seed­ lings and mature plants. Comparison o f the results from the different assays showed that the responses o f PA cells to each com pound correlated more closely with the responses o f seed­ lings and mature plants than did the results o f the Hill reaction assays. Our findings suggest that PA cultured cells would be a suitable screening material for identifying potential herbi­ cides with PET-inhibiting activity. 
  Reference    Z. Naturforsch. 46c, 563 (1991); received December 12 1990/April 12 1991 
  Published    1991 
  Keywords    Photosynthetic Electron Transport (PET) Herbicides, N ew Screening System, Cultured Cells, Photoautotrophic Cells, Pot Assay 
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 Identifier    ZNC-1991-46c-0563 
 Volume    46 
84Author    M. Imoun, ElK. Aoua, Evelyne Duval, DanielleM. Laval-, ArtinRequires cookie*
 Title    Long-Term Effect of Diuron on Chlorophyllous Callus of Bromus erectus: Lipid Composition  
 Abstract    The selection o f plants resistant to photosynthetic herbicides is limited by the low rate o f success in obtaining a photosynthetic callus. An attempt was made to induce diuron tolerance with chlorophyllous tissue strains o f Bromus erectus: growth, chlorophyll contents and total fatty acids were studied during four months o f photoheterotrophic growth in the presence or absence o f 6 diuron. The presence o f the herbicide, which reduced the fresh weight by 40%, provoked increases in chlorophyll levels by 2-or 3-fold, and in galactolipids (especially D G D G) which were enriched in linolenic acid content. These results, closely related to already described characteristics o f herbicide-resistant material, suggest that callus o f Brom us erectus could constitute an interesting photosynthetic in vitro material. 
  Reference    Z. Naturforsch. 46c, 569—5 (1991); received January 11/M arch 25 1991 
  Published    1991 
  Keywords    Bromus erectus Chlorophyll Diuron A daptation, Glycerolipids, Herbicide Resistance, in vitro Cultures 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0569.pdf 
 Identifier    ZNC-1991-46c-0569 
 Volume    46 
85Author    J.Dirk Naber, JackJ S Van RensenRequires cookie*
 Title    Activity of Photosystem II Herbicides Is Related with Their Residence Times at the D 1 Protein  
 Abstract    The reversible binding kinetics o f atrazine, diuron and ioxynil were measured via their bind­ ing and release parameters during steady state inhibition o f electron transport. The parameters were determined in isolated chloroplasts o f peas and o f triazine-resistant and -susceptible bio­ types o f Chenopodium album using a kinetic model. This model is based on the flash-induced oxygen evolution patterns o f isolated broken chloroplasts. It was found that the binding parameters were always significantly higher in the case o f an oxidized acceptor quinone complex as compared with a semi-reduced complex. Triazine resist­ ance seems to originate from a significant increase o f the release kinetics. The release parame­ ters could be used to calculate the residence times o f the herbicides at the D 1 protein. The values o f these residence times were always much higher for the herbicides than for Q B; this explains the inhibition o f electron transport. The only exception was the residence time o f atra­ zine in the resistant biotype, where the value was close to that o f Q B. It is concluded that the "on" kinetics o f a com pound to its binding environment at the D 1 protein are determined principally by the accessibility o f the niche to the com pound. The dif­ ferences in activity between herbicides are mainly due to variations in the release kinetics. 
  Reference    Z. Naturforsch. 46c, 575—5 (1991); received March 18 1991 
  Published    1991 
  Keywords    Chloroplasts, Photosystem II, D 1 Protein, Herbicides, Triazine Resistance 
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 Identifier    ZNC-1991-46c-0575 
 Volume    46 
86Author    H. J. Bestmann, M. Pietschmann, K. Steinmeier, O. VostrowskyRequires cookie*
 Title    Flüchtige Inhaltsstoffe von Cvotalaria ochvoleuca und deren Wirkung auf Schadinsekten* Volatile Constituents from Crotalaria ochroleuca and Their Effect on Pest Insects  
  Reference    Z. Naturforsch. 46c, 579 (1991); received March 20/April 19 1991 
  Published    1991 
  Keywords    Crotalaria ochroleuca, Seed Oil, 2-Isopropyl-3-methoxypyrazine, 2-Pentylfuran, Sitophilus zeam ays, Repellency 
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 Identifier    ZNC-1991-46c-0579 
 Volume    46 
87Author    Hans-Jürgen Sieweke, Eckhard LeistnerRequires cookie*
 Title    tf-Succinylbenzoate: Coenzyme A Ligase, an Enzyme Involved in Menaquinone (Vitamin K2) Biosynthesis, Displays Broad Specificity  
  Reference    Z. Naturforsch. 46c, 585 (1991); received January 18/April 12 1991 
  Published    1991 
  Keywords    M ycobacterium phlei, Biosynthesis, M enaquinones, o-Succinylbenzoate: Coenzyme A Ligase, Substrate Specificity o f o-Succinylbenzoate: Coenzyme A Ligase 
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 Identifier    ZNC-1991-46c-0585 
 Volume    46 
88Author    J. Bednarz, G. H. SchmidRequires cookie*
 Title    Induction of Nitrate Reductase Activity by Arginine in the Filamentous Cyanobacterium Oscillatoria chalybea  
 Abstract    Filamentous Cyanobacterium, Induction o f Nitrate Reductase, Arginine Metabolism In Oscillatoria chalybea, as in other cyanobacteria, nitrate reduction depends directly on photosynthetic activity. Hence, nitrate reduction occurs only in the light and appears inhibited when photosynthesis is inhibited by the herbicide D C M U . Growth o f Oscillatoria cells is pos­ sible on a variety o f exogenous nitrogen sources in the medium and appears largely independ­ ent on the type o f nitrogen source. However, if citrulline is the exogenous nitrogen source or if no exogenous nitrogen source is given in the medium, growth appears alm ost fully inhibited. Nitrate reductase activity measured in French-press particles o f nitrate-grown cells is depend­ ent on the age o f the culture with maximum nitrate reductase activity being reached on the 5th day. Thereafter activity decreases steeply to less than 20% o f the maximal activity within 10 days. Besides the growth stage it is the type o f exogenous nitrogen source used in the medi­ um which is important for the development o f nitrate reductase activity. It appears that in the presence o f nitrate, nitrite and arginine, nitrate reductase activity is induced whereas in the presence o f ammonia or amino acids like alanine nitrate reductase activity is not induced, as already reported in the literature. Nitrate reductase is also induced if arginine and ammonia are simultaneously offered as exogenous nitrogen source. Arginine metabolism in Oscillatoria cells is characterized by the fact that thylakoid preparations o f Oscillatoria catalyze the trans­ formation o f arginine to give ornithine and ammonium. The arginine-metabolizing enzyme differs from the usual arginine-induced arginase. The enzyme seems to be constitutive, not manganese-dependent, exhibiting an approximately 5 times higher substrate affinity to argi­ nine than the known arginase. In the present paper we propose that in Oscillatoria it is arginine which induces the synthesis o f nitrate reductase. 
  Reference    Z. Naturforsch. 46c, 591—5 (1991); received March 20 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0591 
 Volume    46 
89Author    Abteilung Zellchemie, G.S FRequires cookie*
 Title    Activities and Regulation of Enzymes of Carbohydrate Metabolism in Spruce ( Picea abies) M einrad Boll  
 Abstract    Activities o f the glycolytic enzymes were determined in seedlings, callus cultures and cell sus­ pension cultures o f spruce (Picea abies) (L.) (Karst). The rate-limiting enzymes o f the pathway were the hexokinases, ATP: phosphofructo-kinase, fructose-1,6-bisphosphatase and pyruvate kinase. Two phosphofructokinases were found: A T P : fructose-6-phosphate 1-phosphotransferase (PFK) and pyrophosphate :fructose-6-phosphate 1-phosphotransferase (PFP). In the presence o f its activator fructose-2,6-bisphos-phate, PFP had a 4 -5-fold higher specific activity than PFK. PFP could be activated about 20-fold by fructose-2,6-bisphosphate at saturating concentrations o f the substrates (fructose-6-phosphate and pyrophosphate). The increase o f Fmax was accompanied by a strong increase in the apparent affinity o f the enzyme for the substrates. Km for fructose-6-phosphate and pyrophosphate was 0.44 mM and 24 fiM, respectively. Ka for fructose-2,6-bisphosphate was 24 nM. In seedlings, specific activity o f the glycolytic enzymes was 3 0 -3 0 0 percent higher in the hypocotyls, except for fructose-1,6-bisphosphate aldolase, glyceraldehyde-3-phosphate de­ hydrogenase and phosphoglycerate kinase, their activity being 1 0 0 -150 percent higher in the cotyledons, This distribution remained unchanged during periods o f 2 -16 weeks o f cultiva­ tion o f the seedlings. In callus cultures and in cell suspension cultures, grown mixotrophically with different car­ bohydrates, all enzymes were between 1-and 7-fold higher than in autotrophically grown seed­ lings. Incubation o f seedlings in mineral salt mixture containing a carbohydrate resulted in a rapid coordinate increase o f the activities to the levels o f callus-or cell suspension cultures. This induction required a carbohydrate and oxygen. During prolonged cultivation o f cell sus­ pension cultures, when carbohydrate became limiting, activity o f the enzymes slowly declined. 
  Reference    Z. Naturforsch. 46c, 597 (1991); received Dezember 7 1990/April 4 1991 
  Published    1991 
  Keywords    Picea abies, Cell Culture, Carbohydrate M etabolism, PP, -phosphofructokinase, Enzyme Regulation 
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 Identifier    ZNC-1991-46c-0597 
 Volume    46 
90Author    LeszekA. Kleczkowski, Per Villand, Anders Lönneborg, Odd-Arne Olsen, Ernst Lüthi, PlantM. Olecular, BiologyL. AbRequires cookie*
 Title    Plant ADP-Glucose Pyrophosphorylase -Recent Advances and Biotechnological Perspectives (A Review)  
 Abstract    as-N L H , N o rw ay Z. N aturforsch. 46c, 6 0 5 -6 1 2 (1991); received F eb ru a ry 11, 1991 A D P-G lucose P yrophosphorylase, G ene E xpression, M etabolic R egulation, Starch Biosyn­ thesis R ecent advances in studies on p lan t A D P -glucose p y ro p h o sp h o ry lase (A G P), the key en­ zyme o f starch biosynthesis, are presented. A G P c o n stitu tes the First com m itted and highly regulated step o f starch synthesis in all p lan t tissues. T h e im p o rtan ce o f A G P in carb o h y d rate m etabolism and several o f its features, such as p o te n t regulation by cellular effectors (3-phosphoglycerate and P;), an u nu su al tw o su b u n it-ty p es structure, tissue-specific an d devel-opm entally-regulated expression, an d presence o f the A G P -deficient m u tan ts, m ake it an a t­ tractive, but com plex, targ et for b iotechnological m an ip u latio n s. Som e strategies fo r future research on A G P are discussed. 
  Reference    Z. Naturforsch. 46c, 605 (1991) 
  Published    1991 
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 Identifier    ZNC-1991-46c-0605 
 Volume    46 
91Author    Z. NaturforschRequires cookie*
 Title    Two Separate Genes Encode the Catalytic 70 kDa V-ATPase Subunit in Psilotum and Equisetum  
 Abstract    T hom as Starke, T im othy P. L inkkila, an d Jo h a n n Peter G o g arten Department o f Molecular and Cell Biology, U niversity o f Connecticut, Vacuolar type ATPases have been found on various endomem branes o f eukaryotic cells, e.g. lysosomes, chromaffin granules, vesicles derived from the G olgi apparatus, endosom es and vacuoles. Although this ATPase type is targeted to different compartments in one cell, only one gene for each subunit had been found per genome. Using PCR across intron-exon boundaries we show that two different genes encode the cat­ alytic subunit o f the V-ATPase in Psilotum nudum and Equisetum arvense. The substitution rates for the three codon positions and the intervening sequences show that in Psilotum both genes are transcribed and are under selection pressure, however, this seems not to be the case for Equisetum. The relatively high similarity between the two genes found in each species as compared to the interspecies similarities suggest that for som e time after the gene duplication had occurred the two copies were subject to gene conversion mechanisms. An unexpected de­ gree o f conservation o f the intervening sequences themselves is noted and statistically verified, however, no structural constraints that could explain these findings were detected. 
  Reference    Z. Naturforsch. 46c, 613 (1991); received April 5 1991 
  Published    1991 
  Keywords    V-ATPase, Intron-Exon Boundaries, Gene Duplication, Evolution, Polymerase Chain Reaction 
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 Identifier    ZNC-1991-46c-0613 
 Volume    46 
92Author    IgnatB M Inkov, H. Einrich, S. Tro, Tm AnRequires cookie*
 Title    Effect of Azide on the ATPase Activity of Isolated CFj  
 Abstract    The effect o f azide on M g2+-and Ca2+-dependent ATPase o f differently activated CF, iso­ lated from spinach chloroplasts was studied. It is shown that M g2+-ATPase activity is sensitive towards azide irrespective o f the applied method o f enzyme activation. Heat-or trypsin-acti-vated Ca2+-ATPase is also inhibited, whereas methanol-and octylglucoside-stimulated or DTT-activated Ca2+-ATPase is not affected by azide. Preincubation o f the DTT-activated en­ zyme with low concentrations o f M g2+ induces azide susceptibility o f the Ca2+-dependent ATPase. 
  Reference    Z. Naturforsch. 46c, 621—6 (1991); received February 15/April 23 1991 
  Published    1991 
  Keywords    Chloroplast-ATPase (C F, ), Divalent Cation Specificity, Azide Inhibition 
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 Identifier    ZNC-1991-46c-0621 
 Volume    46 
93Author    P. He, K. P. Bader, G. H. Schm, G. Renger, K. P. Bader, G. H. SchmidRequires cookie*
 Title    Mass Spectrometric Analysis of N 2-Formation Induced by the Oxidation of Hydrazine and Hydroxylamine in Flash Illuminated Thylakoid Preparations of the Filamentous Cyanobacterium Oscillatoria chalybea  
 Abstract    Analogue In tobacco chloroplasts hydrazine-dependent dinitrogen form ation measured by mass spec­ trometry as the consequence o f short saturating light flashes is always linked to a substantial oxygen uptake (1990). However, in thylakoids o f the filamentous cyanobacterium Oscillatoria chalybea this dinitrogen formation is not linked to an apparent 0 2-uptake, even at the high concentration o f 1 mM hydrazine. Whereas in tobacco chloroplasts Tris-treatment does not affect hydrazine de­ pendent dinitrogen formation up to a concentration o f 3 mM hydrazine, Tris-treatment o f thy­ lakoids o f O. chalybea affects strongly both oxygen evolution and dinitrogen evolution under a single turnover flash as well as under ten flashes. In contrast to tobacco chloroplasts, the pres­ ence o f hydrazine up to concentrations o f 3 mM does not substantially affect photosynthetic 0-,-evolution. The observed dinitrogen evolution is affected by D C M U regardless whether in­ duced by a single turnover flash or by ten flashes, whereas in tobacco dinitrogen evolution and the 0-,-uptake linked to it (which is not observed in the cyanobacterium) were clearly not af­ fected by D C M U in the single turnover flash. In Oscillatoria the earlier described Photosystem II-mediated H-,0-, formation and decom position is influenced by hydrazine. In the presence o f 300 hm hydrazine the usually present 0 2-uptake leading to H:0 : formation appears dimin­ ished. 
  Reference    Z. Naturforsch. 46c, 629 (1991); received March 21 1991 
  Published    1991 
  Keywords    Filamentous Cyanobacterium, Photosystem II, Water Splitting, S-States, Hydrogen-Peroxide 
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 Identifier    ZNC-1991-46c-0629 
 Volume    46 
94Author    U. Lrich Schreiber, H. Einz, Reising, C. Hristian, N. EubauerRequires cookie*
 Title    Contrasting pH-Optima of Light-Driven 0 2-and H 20 2-Reduction in Spinach Chloroplasts as Measured via Chlorophyll Fluorescence Quenching  
 Abstract    Quenching analysis o f chlorophyll fluorescence by the saturation pulse method is used to investigate the pH-dependency o f 0 2-dependent electron flow in intact spinach chloroplasts with high ascorbate peroxidase activity. When carboxylase/oxygenase activity is blocked, p h o­ tochem ical and non-photochemical quenching are initially low and increase with illumination time. Quenching shows a pH-optimum around pH 6.5, but only when ApH-formation is al­ lowed. It is suggested that overall 0 2-dependent electron flow involves two major com ponents, namely 0 2-reduction (M ehler reaction) and reduction o f the H 20 2 formed in the Mehler reac­ tion, involving enzymic activity o f ascorbate peroxidase and m onodehydroascorbate reduc­ tase. The separated pH-dependencies o f light driven 0 2-reduction (presence o f K C N) and o f H 20 2-reduction (anaerobic conditions) reveal contrasting pH-optim a around pH 5 and 8.5, re­ spectively. Energy-dependent, dark relaxable non-photochem ical quenching is not observed with 0 2-reduction but with H20 2-reduction, and only at pH-values above 6.5. The relevance o f these findings with respect to regulation o f photosynthetic electron flow is discussed. It is sug­ gested that upon limitation o f assimilatory electron flow 0 2-dependent non-assim ilatory flow is responsible for ApH-formation, by which it is autocatalytically stimulated. It is proposed that this autocatalytical reaction sequence is the basis o f the so-called "Kautsky effect" o f chlorophyll fluorescence induction. 
  Reference    Z. Naturforsch. 46c, 635 (1991); received March 6 1991 
  Published    1991 
  Keywords    Chlorophyll Fluorescence, Mehler Reaction, Ascorbate Peroxidase, Energy Dependent Quenching, Photosynthesis Regulation 
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 Identifier    ZNC-1991-46c-0635 
 Volume    46 
95Author    U. Ard, N. C. Hini3, B. Erto, M. Ey Er-F, M. Ernandesab, S. Ro, Ola-PennaaRequires cookie*
 Title    Monosaccharides and Disaccharides Decrease the K m for Phosphorylation of a Membrane-Bound Enzyme ATPase  
 Abstract    Saccharides, Phosphorylation, Sarcoplasmic Reticulum, Enzyme (C a2+, M g2+) ATPase (EC 3.6.1.38) The disaccharides trehalose and sucrose, and to a lesser extent the m onosaccharides glucose and fructose, decrease the apparent K m o f the Ca2+,M g2+-ATPase o f sarcoplasmic reticulum for Pi. This effect is more pronounced at pH 7.4 than at pH 6.2. The enzyme is not phosphory-lated by Pi when the temperature o f the medium is decreased to 0 °C, but when 1.5 m trehalose or sucrose is present phosphoenzyme formation increases to 0.5 nmol E-P/g protein. 
  Reference    Z. Naturforsch. 46c, 644 (1991); received February 1/March 8 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0644 
 Volume    46 
96Author    M. Suw, M.A E Spinoza, I. Sá, F. VillenaRequires cookie*
 Title    X-Ray Studies on Phospholipid Bilayers. XI. Interactions with Chloramphenicol  
 Abstract    X-Ray Diffraction, Phospholipid Bilayer, Erythrocyte M embrane, Chloramphenicol Chloramphenicol is a widely used antibiotic with low levels o f toxicity. However, scanning electron microscopy revealed morphological changes in human erythrocytes when they inter­ acted in vitro with therapeutical concentrations o f chloram phenicol. To explain this shape change, a study concerned with the possible interactions o f this antibiotic with bilayers built-up o f phospholipids located in either side o f the red cell membrane was performed by X-ray diffraction. Results indicated that chloramphenicol was unable to perturb in any significant extent the structure o f the phospholipids under study. The only noticeable effects were phase transitions produced to dim yristoylphosphatidylethanolam ine bilayers. 
  Reference    Z. Naturforsch. 46c, 647 (1991); received January 24 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0647 
 Volume    46 
97Author    E. Rn, Á. Ndez, S. A. AndRequires cookie*
 Title    Phenotypic Traits and Regulatory Role of RNA Folding in Molecular Selection  
 Abstract    We concentrate on instances in which the phenotypic expression o f information encoded in an R N A primary sequence might be revealed by the folding o f the R N A itself. We have discov­ ered that this situation finds concrete realization in the design o f R N A molecules capable o f maximizing the rate o f autocatalytic synthesis when incubated with viral Qß-replicase. This requires that we introduce the notion o f phenotypic traits at the molecular level. Thus, the problem o f finding R N A sequences whose phenotype favorably influences propagation amounts to finding R N A sequences which fold so as to optimize enzymatic performance and are in addition endowed with the proper recognition sites. The p roof that these two problems are indeed equivalent has two steps: First we predict the metastable folded structures formed as a template R N A chain grows by sequential incorporation o f nucleotides. The transient fold­ ed states appear to be involved in the regulation o f the enzyme activity and they occur in a manner which is "oblivious" o f thermodynamic time scales. Secondly, we compute the time-dependent activation energy for relaxation o f each intermediate structure. This is done to es­ tablish constraints necessary for optimization o f the regulatory role o f R N A folding. The search for prospective template sequences is subject to such constraints. Our results aim at elu­ cidating an optimization process realized by molecular selection in de novo (template-free) R N A synthesis by Qß-replicase. We argue that the phenotype which mediates selection is given by metastable folding which emerges together with the printing o f the genotype, that is, within the time span o f a replication turnover. 
  Reference    Z. Naturforsch. 46c, 656 (1991); received March 5/April 3 1991 
  Published    1991 
  Keywords    Biochemical Kinetics, R N A Replication, Statistical Mechanics 
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 Identifier    ZNC-1991-46c-0656 
 Volume    46 
98Author    BodoC., TagRequires cookie*
 Title    Specific Crystal Chemical Interactions between Carcinogenic Aromatic Compounds and Cholesterol  
 Abstract    Polycyclic aromatic hydrocarbons and aromatic amines exercise a highly specific influence on the crystallization o f cholesterol. The strength o f these non-covalent, presumably epitaxial interactions correlates with the carcinogenic activity o f these substances. The presented results are in support o f the assumption that a specific process o f adsorption and crystallization with cholesterol o f the plasma membrane takes place during the initial phase o f the carcinogenesis by aromatic compounds. 
  Reference    Z. Naturforsch. 46c, 663—6 (1991); received September 6 1988/March 21 1991 
  Published    1991 
  Keywords    Carcinogenic Aromatic Compounds, Epitaxial Adsorption, Cholesterol, Plasma Membrane 
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 Identifier    ZNC-1991-46c-0663 
 Volume    46 
99Author    A.M K Han, Sum An, P. Ta, J.C K Atiy Ar, SudhirK. Singh, V.L S Harm, SatyavanS. Harm, A.P B HaduriRequires cookie*
 Title    Studies in Enteric Anthelmintics: Activity Profile of Prodrug of a Bisbenzimidazole [1]  
 Abstract    The comparative anthelmintic activity o f a possible prodrug, 2,2'-dicarbomethoxyamino-5,5'-dibenzimidazolyl methanol (2) with its parent com pound 2,2'-dicarbomethoxyamino-5,5'-dibenzimidazolyl ketone (1) and the reference drug mebendazole (3a) is reported. At a dose o f 25 mg/kg, compound 2 was 100% effective against Ancylostoma ceylanicum in hamsters. Com ­ pound 2 also exhibited a similar order o f activity against Syphacia obvelata, Hymenolepis nana and H. diminuta at a dose o f 100 mg/kg. The drug exhibited lethal effects against metamorphic forms o f A. ceylanicum at a dose o f 100 m g/kg. However the trichostrongylids, Nippostrongy-lus brasiliensis remained unaffected up to a dose o f 250 m g/kg o f 2. Both 1 and 3 a exhibited inferior activity than 2 except against adult A. ceylanicum. The activity o f 1 and 2 has been explained on the basis o f their ability to resist systemic hydrolysis resulting in higher concen­ tration o f the active drug in biophase. 
  Reference    Z. Naturforsch. 46c, 673—6 (1991); received February 13/M ay 8 1991 
  Published    1991 
  Keywords    Prodrug, Anthelmintic Activity, Bisbenzimidazole, Comparative Efficacy 
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 Identifier    ZNC-1991-46c-0673 
 Volume    46 
100Author    B. V. Burger, A. E. Nell, D. Sm, H.S C SpiesRequires cookie*
 Title    Cyclic Glycerol Acetals from the Abdominal Hair Pencil Secretion of the Male African Sugarcane Borer Eldana saccharina (Lepidoptera: Pyralidae)  
 Abstract    Cyclic Acetals, D arm stoff, Eldana saccharina, M ass Spectrometry, N M R Four constituents o f the hair pencil secretion o f the male African sugarcane stalk borer, Eldana saccharina, having a molecular mass o f 312 and peculiar El mass spectra with an excep­ tionally abundant base peak at m /z 103, were isolated preparatively from an extract o f the se­ 
  Reference    Z. Naturforsch. 46c, 678 (1991); received January 8 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0678 
 Volume    46 
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