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1981 (198)
1Author    Wolfgang Lohmann, KlausG. Bensch, Elisabeth Müller, Sa-Ouk KangRequires cookie*
 Title    ESR Investigations on Blood Treated Intravenously with Ascorbic Acid"  
  Reference    Z. Naturforsch. 36c, 1 (1981) 
  Published    1981 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0001.pdf 
 Identifier    ZNC-1981-36c-0001 
 Volume    36 
2Author    Wolfgang Lohmann, KlausG. Bensch, Jörg Schreiber, Elisabeth Müller, Konrad Schwemmle, Herbert Feustel, Rolf-Dieter FillerRequires cookie*
 Title    Paramagnetic Changes in Pulmonary Tumors  
 Abstract    Electron spin resonance studies on healthy and tum erous hum an lung samples have been con­ ducted in order to determ ine possible differences in free radical concentration and shape o f the spectra between the different sections o f the lung. It could be shown that in healthy lung tissue the signal caused by the sem idehydroascorbate (SDA) radical is not prom inent because o f the prevailing high partial oxygen pressure. On form ation o f a tumor, the spin concentration increases, possibly due to the higher metabolic rate; here, the SDA peak is also more pronounced which indicates alterations in the interaction between cell constituents and ascorbic acid. W ithin the tum or, the spin concentration is considerably reduced which is probably caused by a still higher concentration o f ascorbic acid. A ddition o f ascorbic acid to the different lung specimens enhanced the just described effect while oxidizing substances, such as H 2Oa, reversed it. 
  Reference    Z. Naturforsch. 36c, 5—8 (1981); received Septem ber 9/O ctober 20 1980 
  Published    1981 
  Keywords    ESR, Pulmonary Tumors, Ascorbic Acid, Spin Concentration 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0005.pdf 
 Identifier    ZNC-1981-36c-0005 
 Volume    36 
3Author    Rainer Bieganowski, Wilhelm FriedrichRequires cookie*
 Title    Über die Eisenanaloga von Cobalamin und Cobyrsäure* About the Iron Analogues of Cobalamin and Cobyric Acid  
  Reference    Z. Naturforsch. 36c, 9 (1981); eingegangen am 15. Septem ber 1980 
  Published    1981 
  Keywords    Vitamin B12, Cobyric Acid, Fe(III)Cobalam in, Fe(III)Cobyric Acid, Iron-B12-Analogues, UV/VIS-, NMR-, ESR-Spectra 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0009.pdf 
 Identifier    ZNC-1981-36c-0009 
 Volume    36 
4Author    Dagmar Rakow, Rolf Gmelin, Werner ThiesRequires cookie*
 Title    Enzymatische Darstellung und Eigenschaften einiger Desulfoglucosinolate Enzymatic Preparation and Properties of Some Desulfoglucosinolates  
 Abstract    10 different desulfo-glucosinolates belonging to 9 different homologous series have been isolated from the parent glucosinolates by means of a glucosinolate sulfohydrolase from the edible snail H elix pomatia. They were characterized by the following physical-chemical data: molecular weight, melting point, wavelength o f the absorption maximum in the UV-region, m olar absorption coefficient at this maximum, angle o f optical rotation and /?rvalues (thin layer and paper chrom atography). 
  Reference    Z. Naturforsch. 36c, 16 (1981); eingegangen am 20. Oktober 1980 
  Published    1981 
  Keywords    Cruciferae, Glucosinolates, Desulfo-Glucosinolates, Glucosinolate Sulfohydrolase, Physical-Chemical D ata 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0016.pdf 
 Identifier    ZNC-1981-36c-0016 
 Volume    36 
5Author    Thorolf Brosche, Otto Vostrowsky, Fredi Gemeinhardt, Ullrich Asmus, Karl KnoblochRequires cookie*
 Title    Über die Komponenten des ätherischen Öls aus Majorana hortensis Moench On the Essential Oil Components from Majorana hortensis Moench  
 Abstract    Essential Oil, Majorana hortensis M., Terpenes, CN M R D ata, GC-MS D ata By use of 13CNM R, G LC and GC-M S analysis, 75 compounds, mainly mono-and sesquiter­ penes, were identified structurally out o f the essential oil of Majorana hortensis Moench. A distinct seasonal dependence in the biosynthesis o f terpenoids was observed. The specific application o f 13CN M R spectroscopy enabled the structure elucidation o f components o f an essential oil even of that complexity. 
  Reference    Z. Naturforsch. 36c, 23 (1981); eingegangen am 25. A ugust/12. N ovember 1980 
  Published    1981 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0023.pdf 
 Identifier    ZNC-1981-36c-0023 
 Volume    36 
6Author    Rainer Sütfeld, Rolf WiermannRequires cookie*
 Title    Purification of Chalcone Synthase from Tulip Anthers and Comparison with the Synthase from Cosmos Petals  
 Abstract    Chalcone synthase was isolated from both anthers of Tulipa cv. "A peldoorn" and petals of Cosmos sulphureus Cav. After certain prepurification steps, the enzymes were further purified using gel chrom atography on Sephadex G-200 followed by repeated hydroxylapatite absorption chromatography. Both the enzymes showed the same chrom atographic properties. After gel chrom atography as well as after the first hydroxylapatite fractionation, the reaction products appeared as flavanones. However, after the second hydroxylapatite step, production of chalcones was observed. Like the enzyme from tulip anthers, the synthase from Cosmos petals produced the correspondingly substituted chalcones when p-coumaroyl-CoA, caffeoyl-CoA and feruloyl-CoA, respectively, were used as substractes. In both the cases, the ratios o f the different chalcones produced were found to be about the same. The appearance o f chalcone synthesis in this in vitro assay is caused by the complete elim ination of chalcone isomerase in the purification procedure. The importance of the isomerase for flavonoid biosynthesis, particularly in plant systems which are accumulating chalcones, is discussed. 
  Reference    Z. Naturforsch. 36c, 30—3 (1981); received N ovem ber 12 1980 
  Published    1981 
  Keywords    Tulipa, Cosmos, Biosynthesis, Flavonoids, Chalcone Synthase 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0030.pdf 
 Identifier    ZNC-1981-36c-0030 
 Volume    36 
7Author    M. P. Estévez, E. Legaz, L. Olmeda, F. J. Pérez, C. VicenteRequires cookie*
 Title    Purification and Properties of a New Enzyme from Evernia prunastri, which Reduces L-Usnic Acid  
  Reference    Z. Naturforsch. 36c, 35 (1981) 
  Published    1981 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0035.pdf 
 Identifier    ZNC-1981-36c-0035 
 Volume    36 
8Author    K.-H Knobloch, B. Hansen, J. Berlin, ForschungM B H, A. Bteilung, Pflanzliche Zellkulturen, M. Ascheroder WegRequires cookie*
 Title    Medium-Induced Formation of Indole Alkaloids and Concomitant Changes of Interrelated Enzyme Activities in Cell Suspension Cultures of Catharanthus roseus  
 Abstract    Recently m edium conditions have been developed which stim ulate the form ation of the indole alkaloid ajm alicine in cell suspension cultures o f Catharanthus roseus [6]. W hen cells were subjected to these conditions the alkaloid accum ulation was preceded by a 12-fold increase o f the specific activity o f tryptophan decarboxylase. The enzyme activity showed a maxim um two days after the cell transfer into the induction medium and subsequently declined. In contrast the activity of strictosidine synthase, the enzyme condensing tryptam ine and secologanin, was present over the entire measuring period at a constant level. The intracellular content of tryp­ tamine and ajmalicine increased during a period of 6 days after cell transfer and reached a plateau after that time. A possible regulatory function o f tryptophan decarboxylase in indole alkaloid biosynthesis is discussed. 
  Reference    Z. Naturforsch. 36c, 40—4 (1981); received N ovem ber 3 1980 
  Published    1981 
  Keywords    Catharanthus roseus, Indole Alkaloids, Tryptophan Decarboxylase, Strictosidine Synthase, Media Effects 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0040.pdf 
 Identifier    ZNC-1981-36c-0040 
 Volume    36 
9Author    HjA W Schneider, W. LiedgensRequires cookie*
 Title    An Evolutionary Tree Based on Monoclonal Antibody-Recognized Surface Features of a Plastid Enzyme (5-Aminolevulinate Dehydratase)  
 Abstract    5-Aminolevulinate D ehydratase, Evolutionary Tree, Monoclonal Antibodies We describe and discuss an evolutionary tree derived from data which were obtained using monoclonal antibodies. Monoclonal antibodies (see e.g. K öhler and Milstein, N ature 256, 495 (1975)) were prepared against 5-aminolevulinate dehydratase (ALAD) from spinach (Spinacia oleracea) and enabled us to study 13 different A LA D antigenic determ inant characters from origins as diverse as algae, mosses, ferns, gymnosperms and angiosperms. The results show that a dendrogram based on these characters is largely in accord with evolutionary trees based on classical characters. Species, such as Chara or Gnetum, whose system­ atic positions are doubtful, are separated from their alleged relatives. ALAD from the photosynthetic bacterium Rhodopseudomonas spheroides showed antigenic similarities with the plastid ALAD enzyme from spinach, while none of the antibodies against the spinach enzyme reacted with A LAD from the blue-green alga Nostoc muscorum. This finding is relevant to the problem o f the origin o f plastids and shows that monoclonal antibodies may also provide a new approach to the solution o f this problem. The results imply that monoclonal antibodies will prove themselves efficient tools for taxonomic or evolutionary studies. 
  Reference    Z. Naturforsch. 36c, 44 (1981); received Septem ber 3/Septem ber 30 1980 
  Published    1981 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0044.pdf 
 Identifier    ZNC-1981-36c-0044 
 Volume    36 
10Author    Jürgen Benz, Wolfhart RüdigerRequires cookie*
 Title    Chlorophyll Biosynthesis: Various Chlorophyllides as Exogenous Substrates for Chlorophyll Synthetase  
 Abstract    Chlorophyllides a and b, Protochlorophyllide, Bacteriochlorophyllide a, 3-Acetyl-3-devinylchlo-rophyllide a, Pyrochlorophyllide a, Pheophorbide a The esterification o f various chlorophyllides with geranylgeranyl diphosphate was investigated as catalyzed by the enzyme chlorophyll synthetase. The enzyme source was an etioplast membrane fraction from etiolated oat seedlings (Avena sativa L.). The following chlorophyllides were prepared from the corresponding chlorophylls by the chlorophyllase reaction: chlorophyllide a (2) and b (4), bacteriochlorophyllide a (5), 3-acetyl-3-devinylchlorophyllide a (6), and pyro­ chlorophyllide a (7). The substrates were solubilized with cholate which reproducibly reduced the activity of chlorophyll synthetase by 40-50% . It was found that the following compounds were good substrates for chlorophyll synthetase: chlorophyllide a and b, 3-acetyl-3-devinylchloro-phyllide a, and pyrochlorophyllide a. Only a poor or no reaction was found with protochloro­ phyllide, pheophorbide a, and bacteriochlorophyllide. This difference o f reactivity was not due to distribution differences o f the substrates between solution and pelletable membrane fraction. Furthermore, no interference between good and poor substrate was detected. Structural features necessary for chlorophyll synthetase substrates were discussed. 
  Reference    Z. Naturforsch. 36c, 51—5 (1981); received October 10 1980 
  Published    1981 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0051.pdf 
 Identifier    ZNC-1981-36c-0051 
 Volume    36 
11Author    Cornelius Lütz, Jürgen Benz, Wolfhart RüdigerRequires cookie*
 Title    Esterification of Chlorophyllide in Prolamellar Body (PLB) and Prothylakoid (PT) Fractions from ^4 vena sativa Etioplasts  
 Abstract    Etioplast membranes were fractionated into enriched prothylakoid (PT) and prolamellar body fraction (PLB) by known procedures [2]. The photoconversion o f Protochlide to Chlide was 77% in the PT fraction but only 65% in the PLB fraction with optimum NADPH concentrations. The subsequent esterification reaction proceeds in both fractions indicating that the enzyme chlorophyll synthetase is present in both fractions. In the PLB fraction, 10-15% more Chip is formed than in the PT fraction. It is concluded that the concentration of the endogenous phytol precursor is higher in the membranes still present in the PLB fraction than in the PT fraction. 
  Reference    Z. Naturforsch. 36c, 58—6 (1981); received October 24 1980 
  Published    1981 
  Keywords    Prolamellar Bodies, Thylakoids, Chlorophylls 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0058.pdf 
 Identifier    ZNC-1981-36c-0058 
 Volume    36 
12Author    Margrit Bertrams, Käthe Wrage, Ernst HeinzRequires cookie*
 Title    Lipid Labelling in Intact Chloroplasts from Exogenous Nucleotide Precursors  
 Abstract    De «ovo-synthesis o f glycerolipids in chloroplasts is initiated by a stroma enzyme which catalyzes the formation o f lyso-phosphatidic acid from glycerophosphate and acyl-CoA. When these substrates are added to isolated, intact chloroplasts, only glycerophosphate can readily pass through the chloroplast envelope which represents a permeation barrier for acyl-CoA, although higher thioester concentrations destroy this membrane system. At low concentrations of acyl-CoA, which do not impair the envelope, intact chloroplasts metabolize exogenous acyl-CoA in two ways to give free fatty acids and labelled phosphatidyl choline. This indicates that the envelope thioesterase can use exogenous substrates. Isolated, intact chloroplasts fixing radioactive C 0 2 label free fatty acids and acylglycerols but not galactolipids, since they cannot convert 3-phosphoglycerate into UDP-galactose which in vivo is supplied by the cytoplasm. This cooperation was simulated in vitro by adding all enzymes and cofactors necessary for conversion of 3-phosphoglycerate into UDP-galactose to intact chloro­ plasts which then formed labelled monogalactosyl diacylglycerol from labelled C 0 2 . The time required to transfer envelope-made galactolipids from the envelope into thylakoids was studied by incubating intact chloroplasts with radioactive UDP-galactose, subsequent osmotic disruption of organelles with concomitant enzymatic degradation o f UDP-galactose followed by separation o f envelopes and thylakoids. Only after short times (< 1 min) appreciable pro­ portions (20 -30%) o f radioactive galactolipids were recovered in the envelope fraction. This in combination with previous results indicates a rapid galactolipid export from envelopes into thylakoids. 
  Reference    Z. Naturforsch. 36c, 62 (1981); received September 16 1980 
  Published    1981 
  Keywords    Acyl-CoA, UDP-Galactose, Envelope, Impermeability, Lipid Transport 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0062.pdf 
 Identifier    ZNC-1981-36c-0062 
 Volume    36 
13Author    Helmut Formanek, Hermann WeidnerRequires cookie*
 Title    Three Dimensional Structure of the Carbohydrate Moiety of a Lipopolysaccharide. Computer Calculations  
 Abstract    The cell wall of the mutant R 595 of Salmonella minnesola contains a lipopolysaccharide in which only a trisaccharide consisting of three KDO * residues is linked to a lipid termed lipid A. Considering the sterical requirements o f fourteen rotation angles, we have calculated allowed conformation of this trisyccharide unit and its linkage to lipid A. The calculations have been based on averaged crystallographic data of pyranose rings, ester-, N-acetyl-, phosphate-and carboxylgroups. Because of considerable sterical hindrance, there are unique positions for the rotation around the axes 0 3-C 3 of the glucosamine residue and O j -Q o f KDO residue 1 as well as for the rota­ tion of the N-acetylgroup at the C2-atom of glucosamine. Similarly, the rotation angle o f the carboxylgroup on KDO residue 1 and the rotation angles o f the phosphategroup linked to glucos­ amine are highly restricted, while a large range o f angles is allowed for the bond of the ester group to glucosamine. Chemical sequence analysis yields two possibilities for the linkage between the KDO residues 1 and 2. Linkage of 0 4 o f KDO 1 in equatorial position is restricted to a narrow range of angles, whereas the linkage to 0 4 in axial -and to Oa in axial and equatorial position is unfavourable. Furtheron chemical sequence analysis suggests two ways how to link KDO residue 1 and 3. The linkage to the oxygen atom on C7 o f KDO residue 1 can be described by four, the linkage to the oxygen on C6 with three rotation angles. In either case two of the rotations are highly restricted. In the first case the two remaining angles have large rotational freedom, while the second case is sterically unfavorable. The feasibility of the computer calculations has been demonstrated by the construction of a three-dimensional atomic model. 
  Reference    Z. Naturforsch. 36c, 71—8 (1981); received July 10/November 12 1980 
  Published    1981 
  Keywords    Lipopolysaccharide, Carbohydrate Moiety, Structure 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0071.pdf 
 Identifier    ZNC-1981-36c-0071 
 Volume    36 
14Author    N. Weber, K. Wayss, M. Volm, IrmgardK. Iew Itt, K. D. MukherjeeRequires cookie*
 Title    Specific Positional Distribution of Acyl Moieties in Phospholipids is not Generally Deleted in Neoplastic Cells  
 Abstract    The distribution o f acyl moieties at sn-1 and sn-2 positions of cholinephosphoglycerides (CPG) and ethanolaminephosphoglycerides (EPG) has been determined for neurosarcoma, sarcoma 180 and leukemia L 1210. In all the three samples, the positional distribution o f acyl moieties in the two major classes o f phospholipids is found to be similar to that in cellular phospholipids o f most mammalian tissues. The saturated acyl moieties are located predominantly at sn-1 and polyunsaturated acyl moieties at sn-2, whereas the monounsaturated acyl moieties are randomly distributed between these two positions. Apparently, a disruption of specific positioning o f acyl moieties in phospholipids, which hitherto has been in neoplasia, does not exist in all neoplastic cells. 
  Reference    Z. Naturforsch. 36c, 81—8 (1981); received September 26 1980 
  Published    1981 
  Keywords    Positional Distribution o f Acyl Moieties, Phospholipids, Neurosarcoma, Sarcoma 180, Leukemia L 1210 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0081.pdf 
 Identifier    ZNC-1981-36c-0081 
 Volume    36 
15Author    Rainer Jaenicke, Hans-Dietrich Liidemann, Gerhard SchmidRequires cookie*
 Title    Pressure, Temperature and pH Dependence of the Absorption Spectrum of Reduced Nicotinamide Adenine Dinucleotide  
 Abstract    Enzymological studies at high hydrostatic pressure generally involve temperature, pH and pressure as variables, owing to the effect of adiabatic compression and the ionization volume o f the buffer system. In the case of N AD dependent oxidoreductases this implies that the extinction coefficient o f the coenzyme may be affected by p, T and pH, apart from the spectral change accompanying the redox reaction. Measurements o f the pressure dependence of the absorbance of N AD H show a slight red shift and a 1% decrease (3% increase) o f the absorbance at 339 nm (360 nm) at 2 kbar. The pH depen­ dence at the given wavelengths amounts to —(2.4 ± 0.1)% per pH unit (25 °C), while the intrinsic temperature effect (after correction for thermal expansion) is o f the order o f -0.2% per degree (2 0 -3 0 °C). Applying buffers with negligible ionization volume, 366 nm is the optimum wavelength for high pressure studies up to 2 kbar because here the pressure dependent spectral changes o f the N ADH absorption vanish. 
  Reference    Z. Naturforsch. 36c, 84—8 (1981); received October 9 1980 
  Published    1981 
  Keywords    Absorption, Dehydrogenases, High Pressure, NADH, Oxidoreductases, pH Dependence, Tem­ perature Dependence 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0084.pdf 
 Identifier    ZNC-1981-36c-0084 
 Volume    36 
16Author    PatrickC. Hallenbeck, LeonV. Kochian, JohnR. BenemannRequires cookie*
 Title    Hydrogen Evolution Catalyzed by Hydrogenase in Cultures of Cyanobacteria  
 Abstract    Cultures of Anabaena cylindrica, grown on media containing 5 m M N H 4C1 (which represses heterocyst formation), evolved hydrogen after a period o f dark incubation under an argon atmosphere. This hydrogen production was not due to nitrogenase activity, which was nearly undetectable, but was due to a hydrogenase. Cultures grown on media with tungsten substituted for molybdenum had a high frequency of heterocysts (15%) and inactive nitrogenase after nitrogen starvation. The hydrogenase activity of these cultures was three-fold greater than the activity of non-heterocystous cultures. The effects o f oxygen inhibition on hydrogen evolution by hetero-cystous cultures suggest that two pools o f hydrogenase activity exist — an oxygen sensitive hydrogen evolution in vegetative cells and a relatively oxygen-resistent hydrogen evolution in heterocysts. In either case, inhibition by oxygen was reversible. Light had an inhibitory effect on net hydrogen evolution. Hydrogen production in vitro was much higher than in vivo, indicating that in vivo hydrogenase activity is limited by endogenous reductant supply. 
  Reference    Z. Naturforsch. 36c, 87 (1981); received June 13/August 25 1980 
  Published    1981 
  Keywords    Hydrogenase, Cyanobacteria, Heterocysts, Hydrogen Evolution, Hydrogen Metabolism 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0087.pdf 
 Identifier    ZNC-1981-36c-0087 
 Volume    36 
17Author    Günter DöhlerRequires cookie*
 Title    Einfluß von Sauerstoff auf die photosynthetische C 0 2-Fixierung von Synechococcus Effect of Oxygen on Photosynthetic C 0 2 Fixation of Synechococcus  
 Abstract    The cyanobacterium Synechococcus (Anacystis nidulans strain L 1402-1) was grown at +35 °C in air and in air enriched with 2.2 vol.% C 0 2. The effect o f different oxygen concentrations (0, 2, 20, 50, 75 and 99.97 or 97.8 vol.%) was studied in low (0.03 vol.%) and high (2.2 vol.%) C 0 2 concentrations at + 35 °C. After exposure to a nitrogen atmosphere and low C 0 2 content I4C-bicarbonate was mainly incorporated into aspartate and glycine/serine. During oxygenic photosynthetic C 0 2 fixation label in aspartate decreased and a high degree o f radioactivity could be found in 3-phosphoglyceric acid and sugar monophosphates. The Calvin cycle was the main fixing pathway in 2.2 vol.% C 0 2 during anoxygenic and oxygenic conditions independent on the 0 2 concentrations during the experiments. N o oxygen enhancement o f photosynthetic C 0 2 fixation could be found. Possible mechanism involved in C 0 2 fixation pathways and glycolate metabolism underlying the effect o f oxygen was discussed. 
  Reference    Z. Naturforsch. 36c, 93—9 (1981); eingegangen am 9. Oktober 1980 
  Published    1981 
  Keywords    14C 0 2 Fixation, Effect of Oxygen and C 0 2 Concentrations, Synechococcus 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0093.pdf 
 Identifier    ZNC-1981-36c-0093 
 Volume    36 
18Author    KatherineE. Steinback, Klaus Pfister, CharlesJ. AmtzenRequires cookie*
 Title    Trypsin-Mediated Removal of Herbicide Binding Sites within the Photosystem II Complex  
 Abstract    Trypsin treatment of isolated chloroplast thylakoids resulted in a step-wise modification o f surface exposed membrane polypeptides. Early effects o f the protease action resulted in a decrease in inhibitory activity of atrazine, diuron, pyrazon, and bromacil, but an initial increase in the activity of bromnitrothymol and dinoseb. Direct measurements o f atrazine binding demonstrated that decreased inhibitory activity corresponded to a decreased binding affinity in the treated membranes. Longer term effects o f trypsin caused removal of atrazine binding sites and a concomitant block o f electron transport chains. The data are consistent with a concept that the traizine receptor protein is a component o f the electron transport chain which is successively degraded in two or more steps by protease attack. Polyacrylamide gel electrophoresis of trypsin-treated membranes and sub-membrane fragments derived from these membranes revealed that several polypeptides are membrane surface exposed. The involvement o f a 32000 dalton polypeptide in creating the atrazine binding site is discussed. 
  Reference    Z. Naturforsch. 36c, 98 (1981); received September 221980 
  Published    1981 
  Keywords    Photosynthesis, Atrazine, Diuron, Chloroplast Membranes, Receptor Protein 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0098.pdf 
 Identifier    ZNC-1981-36c-0098 
 Volume    36 
19Author    Magdolna Droppa, Sándor Demeter, Zsuzsa Rózsa, G. Ábor HorváthRequires cookie*
 Title    Reinvestigation of the Effects of Disalicylidenepropanediamine (DSPD) and 2-HeptyM-hydroxyquinoline-N-oxide (HQNO) on Photosynthetic Electron Transport  
 Abstract    The effects of disalicylidenepropanediamine (DSPD) and 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) on photosynthetic electron transport have been reexamined. The results confirm earlier observations that lower concentrations of DSPD (< 100 hm) block electron transport at the levels of ferredoxin and plastocyanin. High concentrations o f DSPD even inhibit electron transport from HaO -> pBQ, suggesting that DSPD has an inhibitory site in PS II as well. Thermoluminescence curves o f DSPD and DCMU treated chloroplasts were very similar, showing that the third inhibitory site o f DSPD is similar to that o f DCMU. Both oxidized and reduced HQNO, (0 .6 -6 hm) blocked electron transport from H20 -* pBQ, H20 -*■ MV/FeCy to a similar extent. The effect of HQNO on thermoluminescence showed that its inhibitory site is probably located before that o f DCMU. At higher concentration (> 6 h m) , the H20 -*■ MV/FeCy reactions were more strongly inhibited by oxidized HQNO than those occuring from H20 -> pBQ, suggesting that a new site o f inhibition must also be considered. The dark decay of the P 700 signal was not influenced by the addition o f oxidized HQNO which shows that the new inhibitory site of HQNO is located between plastoquinone and P 700. The reduced form of HQNO did not inhibit non-cyclic electron transport around PS I. Indeed, at higher concentrations, reduced HQNO even accelerates electron flow from DCIP -» MV and the dark reduction of P 700, thus suggesting that this compound has a "donor-mediator" function in PS I. 
  Reference    Z. Naturforsch. 36c, 109 (1981); received September 8/October 28 1980 
  Published    1981 
  Keywords    Inhibitors, Electron Transport, Chloroplasts, Thermoluminescence 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0109.pdf 
 Identifier    ZNC-1981-36c-0109 
 Volume    36 
20Author    Requires cookie*
 Title    Px 10  
 Abstract    x V/Mx a c o 2 ppm PM = mg C 0 2 tumover/g FW, MCo2 = 4.4 x 104 mg, p = 1 atm, R = gas constant (0.082), T = 293 K, K = 9 0 1 x h -\ M = FW of potato tubers in g, A C 0 2 = spectrometer readings (cf. [18]). 
  Reference    Z. Naturforsch. 36c, 115 (1981) 
  Published    1981 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0115.pdf 
 Identifier    ZNC-1981-36c-0115 
 Volume    36 
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