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1992[X]
1Author    B. Posner, G. B. Feige, S. H. UneckRequires cookie*
 Title    Studies on the Chemistry of the Lichen Genus Umbilicaria Hoffm  
 Abstract    The aromatic com pounds o f more than 400 specimens o f 33 species o f the lichen genus Umbilicaria have been investigated by HPLC. Additionally to gyrophoric, hiascic, lecanoric, ovoic and umbilicaric acids, atranorin, norstictic and stictic acids, the new depside crustinic acid has been found. Structure elucidation o f crustinic acid was made by means o f HPLC cochromatography, N M R , UV and mass spectrometry. N ow the secondary product patterns o f Umbilicaria species are discussed and their significance for systematic purposes is shown. 
  Reference    Z. Naturforsch. 47c, 1 (1992); received July 22/October 24 1991 
  Published    1992 
  Keywords    Lichens, Umbilicaria, Aromatic Lichen Substances, Crustinic Acid, HPLC 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0001.pdf 
 Identifier    ZNC-1992-47c-0001 
 Volume    47 
2Author    Z. NaturforschRequires cookie*
 Title    Lipophilic Phenolic Constituents from Helichrysum Species Endemic to Madagascar  
 Abstract    M ichel R an d riam in ah y a, Peter Proksch3, L udger W itteb, and V ictor W rayc Eight species o f the genus H elichrysum , all o f them endemic to Madagascar, were analyzed for lipophilic phenolic constituents deposited on the surfaces o f leaves and stems. A total o f 35 com pounds was isolated and identified by spectroscopic means. C halcones (10) comprised the largest group o f com pounds encountered, followed by flavonols (8), flavanones (7), flavones (4), benzophenones (3) and phloroglucinol derivatives (3). M any o f the flavonoids were char­ acterized by unsubstituted B-rings and/or C-or O-bound prenyl or neryl substituents. The H elichrysum species analyzed in this study are very similar to African species o f this genus with regard to their lipophilic phenolic constituents. The phenolic com pounds studied thus appear to be conservative chemical characters o f H elichrysum that were retained more or less un­ changed during the origin o f endemic taxa in Madagascar. 
  Reference    Z. Naturforsch. 47c, 10—16 (1992); received July 29 1991 
  Published    1992 
  Keywords    H elichrysum, Asteraceae, Flavonoids, Benzophenones, Phloroglucinols 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0010.pdf 
 Identifier    ZNC-1992-47c-0010 
 Volume    47 
3Author    M. Ari, C. Arm En, T. Erencio, Marí, JesúS. Sanz, Marí, Luisa Fonseca, SalvadorM. Áñ Ez, JoséR. Luis, ÍosRequires cookie*
 Title    Phenolic Compounds from Lactuca viminea L  
 Abstract    The aerial part o f Lactuca viminea L. was examined for the presence o f phenolic com ­ pounds. Six different flavonoids were isolated and identified by U V spectra, TLC, HPLC-D A D , 'H NM R and l3C N M R . They were identified as apigenin, luteolin, quercetin, luteolin-7-O-glucoside, quercetin-3-O-glucoside and luteolin-7-0-glucuronide-6"-m ethyl ester. Three phenolic acids were also detected: caffeic, ferulic and chlorogenic acid. 
  Reference    Z. Naturforsch. 47c, 17 (1992); received June 26/July 31 1991 
  Published    1992 
  Keywords    Lactuca viminea, Flavonoids, Phenolic Acids, Asteraceae 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0017.pdf 
 Identifier    ZNC-1992-47c-0017 
 Volume    47 
4Author    F. Ran, Z-Jo Sef, M. Arner, BiancaK. ErpRequires cookie*
 Title    Composition of Iridals, Unusual Triterpenoids from Sword-Lilies, and the Seasonal Dependence of Their Content in Various Parts of Different Iris Species  
 Abstract    The com position o f iridals, new triterpenoids from sword-lilies, and their fatty acid esters in roots, rhizomes and leaves o f I. germ anica Linn., I. pseudacorus Linn, and two different varie­ ties o f I. pallida Lam. was determined. Quantitative analysis o f their total content in the var­ ious parts o f the plants in the course o f the year showed specific seasonal changes in rhizomes and leaves. Based on these results the possible significance o f these com pounds for the plants is discussed. 
  Reference    Z. Naturforsch. 47c, 21 (1992); received M ay 21/August 29 1991 
  Published    1992 
  Keywords    Iridals, Triterpenoids, Iris pallida Lam, Iris germ anica Linn, Iris pseudacorus Linn 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0021.pdf 
 Identifier    ZNC-1992-47c-0021 
 Volume    47 
5Author    H. Budzikiewicz, H. Schröder, UndK T ArazRequires cookie*
 Title    Zur Biogenese der Pseudomonas-Siderophore: Der Nachweis analoger Strukturen eines Pyoverdin-Desferriferribactin-Paares [ 1 ]  
 Abstract    The Biogenesis o f Pseudomonas Siderophores: The P ro o f o f A nalogous Structures o f a P yoverdin/D esferriferribactin Pair [1] When grown in an iron-deficient medium Pseudomonas aptata produces both a desferri-fer-ribactin and a pyoverdin. The identical sequence o f the peptide chain confirms the hypothesis that desferri-ferribactins are the biogenetic precursors o f pyoverdins. 
  Reference    Z. Naturforsch. 47c, 26 (1992); received August 5/September 30 1991 
  Published    1992 
  Keywords    Pseudom onas aptata, Siderophores, Pyoverdin, Ferribactin Biogenesis 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0026.pdf 
 Identifier    ZNC-1992-47c-0026 
 Volume    47 
6Author    BeateD. Rechsler-T, Ann Hielm, D. Ieter, D. Örnem, Ann, H. Orst SengerRequires cookie*
 Title    Labeling and Isolation of Hemes from Scenedesmus  
 Abstract    Protoheme and small quantities o f heme a were isolated and purified from the wild type and the developm ental mutant, C-2 A', o f Scenedesmus obliquus. In fast growing synchronized WT cells and greening cells o f the mutant protoheme could be labeled with [ l -l4C]glutamate and [2-14C]glycine. The labeling o f heme a was ambiguous and o f minor quantity. During rapid chlorophyll biosynthesis the turnover o f protoheme was determined by a pulse-chase experi­ ment to have a half-life o f 2 h. At the current stage o f investigations the question, whether [2-l4C]glycine is incorporated into protoheme via the Shemin pathway or via photorespiration or refixation o f l4COz during general metabolism remains open. 
  Reference    Z. Naturforsch. 47c, 33—4 (1992); received July 16/September 16 1991 
  Published    1992 
  Keywords    Scenedesm us obliquus, Protoheme, Heme a, ALA Biosynthesis, Protoheme Turnover 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0033.pdf 
 Identifier    ZNC-1992-47c-0033 
 Volume    47 
7Author    A. Rkadiusz, K. Ozubek, M. Alg, O. Rzata, N. Ietubyc, A. Leksander, F. SikorskiRequires cookie*
 Title    Modulation of the Activities of Membrane Enzymes by Cereal Grain Resorcinolic Lipids  
 Abstract    Cereal Grains, Resorcinolic Lipids, Alk(en)ylresorcinols M embrane Enzymes, Acetylcholinesterase, Ca-ATPase Resorcinolic lipids, amphiphilic com pounds from cereal grains show strong effects upon the activity o f membrane enzymes. The concentrations for 50% inhibition o f erythrocyte mem­ brane acetylcholinesterase were in the range o f 1 8 -9 0 (xm and were dependent on the length o f the aliphatic side chain o f the hom ologue and on the m odification o f hydroxyl groups in the benzene ring. Sulfonation o f OH groups resulted in a drastic decrease o f the inhibitory poten­ cy. The effect o f resorcinolic lipids on the activity o f Ca2+(calm odulin)-ATPase was the op p o­ site. U p to concentrations o f 50 alk(en)ylresorcinols stimulated the activity o f this enzyme and only slight inhibition (approx. 30%) was observed above 100 |i m . The results suggest that the effect o f resorcinolic lipids might depend on their ability to alter the bilayer properties. M ost probably these com pounds decrease the mobility o f membrane phospholipid molecules. 
  Reference    Z. Naturforsch. 47c, 41 (1992); received October 18 1990/April 16 1991 
  Published    1992 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0041.pdf 
 Identifier    ZNC-1992-47c-0041 
 Volume    47 
8Author    D. Ariusz, G. J. Struski, A. Rkadiusz, K. OzubekRequires cookie*
 Title    Cereal Grain Alk(en)ylresorcinols Protect Lipids against Ferrous Ions-Induced Peroxidation  
 Abstract    Cereals, Rye, Resorcinolic Lipids, 5-«-alk(en)ylresorcinols, Lipid Peroxidation Resorcinolic lipids, significant constituents o f cereal grains are long chain (C 1 3 -C 2 7) de­ rivatives o f l,3-dihydroxy-5-alk(en)ylbenzene. It was shown that due to their phenolic nature resorcinolic lipids are effective in protection against fatty acids peroxidation. The phospho­ lipid bilayers appeared to be also protected in the presence o f these com pounds. The maximal inhibition o f peroxidation was 5 0 -9 0 % with IE50 values in the range o f 0 .8 5 -3 .6 mol% o f resorcinolic lipids. 
  Reference    Z. Naturforsch. 47c, 47 (1992); received October 18 1990 
  Published    1992 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0047.pdf 
 Identifier    ZNC-1992-47c-0047 
 Volume    47 
9Author    B. Urkhard Vechtel, ElfriedeK. Pistorius, H. Ans, G. Eo, RgR. UppelRequires cookie*
 Title    Occurrence of Secondary Carotenoids in PS I Complexes Isolated from Eremosphaera viridis De Bary (Chlorophyceae)  
 Abstract    Photosystem I complexes o f Eremosphaera viridis D e Bary (Chlorophyceae, Chlorococcales) were isolated and partially characterized. In the isolated PS I complexes, peptides o f 6 4 -6 0 , 26, 23, 20, 15, 11 and 8.5 kD a could be detected. When Erem osphaera was grown under regular conditions the pigment com position o f the isolated PS I com plexes was similar to that found in PS I complexes from other green algae. However, when Eremosphaera was grown under nitro­ gen deficient conditions, PS I complexes contained the secondary carotenoids canthaxanthin and traces o f astaxanthin and echinenone in addition to ß-carotene, violaxanthin and lutein. The results presented indicate that the secondary carotenoids are associated with the LHC I o f PS I. To our knowledge this represents the first report about the association o f secondary caro­ tenoids with light harvesting pigment protein complexes o f green algae. 
  Reference    Z. Naturforsch. 47c, 51—56 (1992); received July 25/September 9 1991 
  Published    1992 
  Keywords    Eremosphaera viridis, Photosystem I, Secondary Carotenoids, N-Deficiency, LHC I 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0051.pdf 
 Identifier    ZNC-1992-47c-0051 
 Volume    47 
10Author    SuleymanI. Allakhverdiev, VyacheslavV. KlimovRequires cookie*
 Title    Photoreduction of NA DP+ in Photosystem II of Higher Plants: Requirement for Manganese  
 Abstract    Photoreduction o f N A D P +, Photosystem II, Pheophytin, M anganese, Reaction Center The effects o f reversible manganese extraction on N A D P + photoreduction were studied with higher plant subchloroplast preparations o f photosystem II (PS II). Under anaerobic conditions, when the reaction centers (RCs) o f PS II are "closed" (i.e. in the state [P680 Pheo] QA), and in the presence o f ferred o x in -ferred o x in -N A D P + reductase, N A D P + reduction is observed at a rate o f 0 .8 -1 .1 nm ol/m g x chlorophyll x h. After com plete removal o f man­ ganese from PS II, the rate o f N A D P + reduction is reduced 4 0 -50-fold. U pon the addition o f M n at a concentration o f approx. 4 Mn atom s per reaction center, the N A D P + reduction is restored up to 8 5 -9 0 % o f the initial value. When half o f this am ount o f Mn is com bined with about 40 times o f the equivalent concentration o f other divalent ions (C a2+, Sr2+, M g2+ etc.) the reaction is also reactivated. D inoseb (10-6 m) an inhibitor o f electron transfer in PS II pre­ vents N A D P + photoreduction. It is concluded that under conditions when the first quinone acceptor, QA, is in its reduced state (QäX electrons are transferred from reduced pheophytin (P heoT) to N A D P +, indicating that PS II can reduce N A D P + without the participation o f PS I. On the basis o f these and literature data, an alternate pathway for electron phototransfer in PS II reaction centers o f higher plants is suggested. Some problems concerning the Z-scheme are discussed. 
  Reference    Z. Naturforsch. 47c, 57 (1992); received August 6 1990/July 9 1991 
  Published    1992 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0057.pdf 
 Identifier    ZNC-1992-47c-0057 
 Volume    47 
11Author    Rekha Chaturvedi, M. Singh, P. V. SaneRequires cookie*
 Title    Photoinactivation of Photosynthetic Electron Transport under Anaerobic and Aerobic Conditions in Isolated Thylakoids of Spinach  
 Abstract    The effect o f exposure to strong white light on photosynthetic electron transport reactions o f PS I and PS II were investigated in spinach thylakoids in the absence or presence o f oxygen. Irrespective o f the conditions used for photoinactivation, the damage to PS II was always much more than to PS I. Photoinactivation was severe under anaerobic conditions compared to that in air for the same duration. This shows that the presence o f oxygen is required for prevention o f photoinactivation o f thylakoids. The susceptibility o f water-splitting com plex in photoinactivation is indicated by our data from experiments with chloride-deficient chloro-plast membranes wherein it was observed that the whole chain electron transport from DPC to MV was much less photoinhibited than that from water. The data from the photoinactivation experiments with the Tris-treated thylakoids indicate another photodam age site at or near reaction centre o f PS II. D CM U -protected PS II and oxygen-evolving com plex from p h oto­ inactivation. D C M U protection can also be interpreted in terms o f the stability o f the PS II complex when it is in S2 state. 
  Reference    Z. Naturforsch. 47c, 63—6 (1992); received August 16 1991 
  Published    1992 
  Keywords    Photoinactivation, Anaerobiosis, Inhibitors, Photosynthetic Electron Transport, Trypsinization 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0063.pdf 
 Identifier    ZNC-1992-47c-0063 
 Volume    47 
12Author    P. He, R. Schulder, K. P. Bader, G. H. SchmidRequires cookie*
 Title    Effect of Cyanide on the S2-and S3-State in the Filamentous Cyanobacterium Oscillatoria chalybea  
 Abstract    Filam Low concentrations o f cyanide affect the flash-induced oxygen evolution pattern in thyla-koid preparations o f the filamentous cyanobacterium Oscillatoria chalybea. At a cyanide con­ centration o f 2 x 10~6 m the effect lies exclusively on the S2-and S3-state whereas the sub­ sequent flash yields and the steady state are barely affected, showing that the reaction center is not touched by the reagent. The influence o f the chemical is characterized by the fact that at basic pH (7 .5 -8 .5) the deactivation mode o f S2 and S3 is changed, showing that the cyanide-ion is the reactant. Whereas in the control the deactivation o f S, yields as usual S, and S_,, the deactivation pattern in the presence o f cyanide shows that S2 deactivates -without giving S, -, to a more reduced state, probably S0. In the flash pattern the two signal amplitudes o f the first two flashes are lowered to zero in the presence o f 2 x 10~6 m cyanide and becom e uptake signals at higher cyanide concentrations. It is seen that in the presence o f cyanide S2 and to a lesser extent S3 in the Oscillatoria system apparently react with oxygen. In tobacco thylakoids no effect o f cyanide on the flash pattern itself is observed, even at higher concentrations (e.g. 1 0 " 4 m), although the signal amplitudes o f the entire pattern are affected at such concentra­ tions. Photosystem II o f cyanobacteria is characterized by the absence o f the two extrinsic 16 kD a and 23 kD a peptides. As shown by mass spectrometry inside-out vesicles from tobacco thylakoids, in which these two extrinsic peptides have been removed by NaCl-washing, exhibit sim ultaneously flash-induced 0 2-evolution and an 0 2-uptake which both require the presence o f CL and C a2+ ions. Both the evolution signal and the uptake signal are D C M U sensitive and are inhibited by KCN. An amperometrically measured flash pattern o f inside-out tobacco ves­ icles shows, if the assay is supplemented with CL ions, the usual flash pattern known from the literature. The experiments seem to indicate that even in the washed inside-out condition the S-state system o f higher plants is much less sensitive to ambient oxygen than in the phylo-genetically older system o f the filamentous cyanobacterium Oscillatoria chalybea. 
  Reference    Z. Naturforsch. 47c, 69—7 (1992); received September 30 1991 
  Published    1992 
  Keywords    entous Cyanobacterium, Water-Splitting, S-States 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0069.pdf 
 Identifier    ZNC-1992-47c-0069 
 Volume    47 
13Author    Anke Schaumburg, H. Ansjörg, A. W. Schneider-Poetsch, C. EckerskornRequires cookie*
 Title    Characterization of Plastid 5-Aminolevulinate Dehydratase (ALAD; EC 4.2.1.24) from Spinach (Spinacia olevacea L.) by Sequencing and Comparison with Non-Plant ALAD Enzymes* in cooperation with  
 Abstract    Plastid 5-Am inolevulinate Dehydratase (EC 4.2.1.24), Primary Structure Peculiarities, Transit Peptide, M g2+-Binding, Active Centre We have sequenced 5-am inolevulinate dehydratase (ALAD; EC 2.4.1.24) o f a plant. A full-length cD N A clone (1727 bp) encoding this enzyme has been identified by immunoscreening a lambda gt 11 cD N A library o f spinach. A L A D is not a plant-specific enzyme; however, the plant enzyme differs from the well known A L A D enzymes o f bacteria, yeast and animals in structural and biochem ical properties and in that it is located in the plastid. Differences and hom ologies can be traced back to the molecular level. The mature A L A D subunit, whose N-terminus was determined by autom atic Edman degradation, is a protein o f 367 amino acid residues and has a M T o f 40,132. This figure is in the range o f molecular weights o f non-plant A L A D s. The active centre is highly conserved and the same is true for the ion-binding domain, except that 4 cysteines o f the non-plant enzymes (binding Zn2+) have disappeared and a total o f 6 aspartic acids meets the demands o f M g2+-binding. However, there are more distinct dif­ ferences. Apart from a transit sequence o f 56 amino acids targeting the plastid, the N-terminal part o f the mature plant enzyme differs considerably from non-plant A L A D enzymes. It is rich in prolines and hydroxylated amino acids. The apparent M r on SD S-PAG E is 45,000 or high­ er, but up to now posttranslational modifications have not been found. 
  Reference    Z. Naturforsch. 47c, 77—8 (1992); received September 16/November 4 1991 
  Published    1992 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0077.pdf 
 Identifier    ZNC-1992-47c-0077 
 Volume    47 
14Author    KenjiM. Atsui, Hiroyuki Shinta, H. Irom, Itsu Toyota, Tadahiko Kajiwara, AkikazuH. AtanakaRequires cookie*
 Title    Comparison of the Substrate Specificities of Lipoxygenases Purified from Soybean Seed, Wheat Seed, and Cucumber Cotyledons  
 Abstract    Lipoxygenases were highly purified from soybean seed, wheat seed and cucumber cotyle­ dons. Substrate specificities o f these lipoxygenases were studied by using an entire series o f (co6Z ,co9Z)-C 13~C24-dienoic acids as synthetic substrate analogues. Soybean lipoxygenase-1 and cucumber lipoxygenase showed broad specificities for these substrates while wheat lipoxygenase showed narrow specificities. Position o f dioxygenation to each substrate was an­ alyzed by high performance liquid chromatography. W ith soybean lipoxygenase-1 elongation o f the distance between the terminal carboxyl group and the site o f hydrogen removal in a substrate decreased the positional specificity o f dioxygenation, while, with cucumber lipoxy­ genase, shortening the distance decreased the specificity. It was suggested that cucumber lipoxygenase and soybean lipoxygenase-1 recognized the terminal carboxyl group o f a sub­ strate to arrange it only in one orientation at the reaction center. In case o f wheat lipoxygen­ ase, recognition o f the carboxyl group was thought to have crucial and essential role to secure the activity. 
  Reference    Z. Naturforsch. 47c, 85—8 (1992); received M ay 8/A ugust 27 1991 
  Published    1992 
  Keywords    Lipoxygenase, Cucumber Cotyledons, Soybean Seed, W heat Seed, Substrate Specificity 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0085.pdf 
 Identifier    ZNC-1992-47c-0085 
 Volume    47 
15Author    Rodrigo Lois, Klaus HahlbrockRequires cookie*
 Title    Differential Wound Activation of Members of the Phenylalanine Ammonia-Lyase and 4-Coumarate: Co A Ligase Gene Families in Various Organs of Parsley Plants  
 Abstract    Phenylpropanoid M etabolism , Gene A ctivation, W ounding, Fungal Elicitor, U V Light We analyzed the developm ental regulation and the activation by wounding o f several stress-related genes in various parsley organs. The genes encode phenylalanine ammonia-lyase (PAL) and 4-coum arate: C oA ligase (4 CL), two enzymes o f general phenylpropanoid m etabo­ lism; a flavonoid specific enzyme, chalcone synthase (CHS); a furanocoumarin specific en­ zyme, bergaptol O-methyltransferase (BM T); and a pathogenesis-related protein (PR 1). All genes or gene families exhibited high levels o f expression in roots and during certain stages o f leaf development. PAL, 4 CL and CHS were preferentially expressed in young leaves, BMT and PR 1 in old leaves. An appreciable increase in CHS m R N A levels was observed in w ound­ ed leaves. By contrast, root w ounding led to a decrease in the existing CHS m R N A levels. A biphasic response (a decrease followed by an increase) to wounding was seen for BM T and PR 1 m R N A s in roots and for BM T m R N A in attached leaves. U sing gene-specific oligonu­ cleotide probes to measure the expression rates o f three o f the four PAL genes and o f the two 4 CL genes separately we observed a differential behavior o f the individual family members under many o f the conditions tested. W hile PAL-3 was preferentially activated in wounded leaves and 4CL-1 in wounded roots, PAL-2 and 4C L -2 were primarily responsible for the high constitutive expression levels in roots and flowering stems respectively. Despite the differential expression o f their individual members, the PAL and 4 CL gene families displayed very similar changes in the overall patterns o f expression, reflecting their closely related functions in phen­ ylpropanoid metabolism. 
  Reference    Z. Naturforsch. 47c, 90—9 (1992); received September 4 1991 
  Published    1992 
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 Identifier    ZNC-1992-47c-0090 
 Volume    47 
16Author    Divya Mishra, Ahlert SchmidtRequires cookie*
 Title    Regulation and Partly Purification of the ATP-Sulfurylase from the Cyanobacterium Synechococcus 6301  
 Abstract    ATP-sulfurylase from the cyanobacterium Synechococcus 6301 was regulated in vivo during growth in batch culture. The activity was highest at the third day after inoculation, declining afterwards to a level found in resting cells. During growth with air supplemented with 2% CO, this activity increased 3-fold compared to controls grown with normal air as C 0 2 source. Addition o f either nitrite or urea enhanced ATP-sulfurylase activity about 2-fold, whereas cys­ teine and especially methionine decreased ATP-sulfurylase activity to 5% o f controls without treatment. The ATP-sulfurylase was purified by conventional techniques using D EAE-cellulose chro­ matography and further separation on blue sepharose achieving a 250-fold increase in the spe­ cific activity. An apparent o f 5 for APS and o f 40 |iM for pyrophosphate was deter­ mined with the purified enzyme fraction. 
  Reference    Z. Naturforsch. 47c, 95 (1992); received September 26 1991 
  Published    1992 
  Keywords    ATP-Sulfurylase, Cyanobacterium, Synechococcus, Sulfate A ctivation, Regulation 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0095.pdf 
 Identifier    ZNC-1992-47c-0095 
 Volume    47 
17Author    J. Polster, M. Schwenk, E. BengschRequires cookie*
 Title    The Role of Boron, Silicon and Nucleic Bases on Pollen Tube Growth of Lilium longiflorum (L.)  
 Abstract    It is possible to obtain pollen germination and pollen tube growth in vitro if boric acid is present. In this work the effect was studied using as a semiquantitative parameter the mean length (J) o f Lilium longißorum pollen tubes. Pollen tube growth was examinated in depend­ ence on boric acid, ortho-silicic acid, nucleic bases, Ca2+ and Zn2+ in 10% sucrose solution. The maximum o f 7is obtained for concentrations between 2 -2 0 ppm boron. The simultaneous supply o f silicon added as water glass leads to a synergistic stimulation effect on pollen tube growth and facilitates branching. The silicon action is preceded o f a pollen tube growth inhibi­ tion period during 3 h. Adenine and guanosine are able to substitute partially boron as pollen germination and pollen tube growth stimulator. Concentrations o f 100 ppm adenine leads to half the boron effect. The same stimulation effect is obtained by guanosine. Ca2+ can partially substitute boron as well. The stimulation action o f boron is significantly attenuated by Zn2+ and by the herbicide Dicuran. These and preceding results from physiological studies indicate that boron and silicon should be essential trace elements for the regulation o f molecular bio­ logical processes. 
  Reference    Z. Naturforsch. 47c, 102—2 (1992); received June 13/September 16 1991 
  Published    1992 
  Keywords    Pollen Tube Growth, Boron, Silicon, Lilium longiflorum, Germination 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0102.pdf 
 Identifier    ZNC-1992-47c-0102 
 Volume    47 
18Author    Hans-Joachim Ballach, Simone Oppenheimer, Jan MooiRequires cookie*
 Title    Reactions of Cloned Poplars to Air Pollution: Premature Leaf Loss and Investigations of the Nitrogen Metabolism  
 Abstract    Populus nigra L. cv. Loenen, P. m axim owiczii Henry x P. nigra L. cv. Rochester, Air Pollu­ tants, Nitrogen M etabolism , Premature Leaf Drop Y oung poplar cuttings (Populus nigra L. cv. Loenen and P. m axim owiczii Henry x P. nigra L. cv. Rochester) were exposed for six weeks in open-top chambers to realistic concentrations o f pollutant mixtures: 1) control; 2) S O ,/N O x; 3) 0 3/ N 0 x and 4) S 0 2/ 0 3/ N 0 x. In this sequence o f fumigation variants, the degree o f influence o f the various parameters o f the nitrogen m e­ tabolism and o f premature leaf drop increased very frequently compared to the control plants, P. nigra L. proving to be the more sensitive species. The elevated Kjeldahl nitrogen content o f the fumigated leaves was accompanied by either an increase in free am ino acids or in total protein or, in the case o f particularly large rises (SO ,/ 0 3/ N 0 x variants), by increases in both substance groups. Proteolytic processes as a cause o f the elevated content o f free amino acids could be excluded to a large extent. A diminished de novo synthesis o f proteins obviously led to a shift in the amino acid/protein relationship. In the younger fumigated leaves, the total concentration o f free amino acids exceeded the values o f the older leaves. The elevated amino acid content o f the fumigated leaves was produced to a high degree by the glycolate pathway and the Krebs cycle. The increased turnover o f the car­ bon skeletons was connected with a drastic starch degradation, especially in the older leaves. The interaction o f the amino acid and carbohydrate m etabolisms is probably an important regulator in the prom otion o f rapid growth o f young leaves in order to com pensate premature leaf loss. 
  Reference    Z. Naturforsch. 47c, 109 (1992); received July 9/September 4 1991 
  Published    1992 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0109.pdf 
 Identifier    ZNC-1992-47c-0109 
 Volume    47 
19Author    Bernd Schneider, Manfred Stock, Gernot Schneider, HorstRobert Schütte, Klaus Schreiber, Angela Brauner, ErnstUlrich KaußmannRequires cookie*
 Title    Metabolism of Amitrole in Apple: I. Soluble Metabolites from Mature Fruits  
 Abstract    Mature fruits from apple trees contain residual amounts of radiolabel derived from soil-ap-plied [3,5-14C]amitrole. This report deals with characterization of the soluble part of this radio­ activity. By GC/MS of suitable derivatives 3-(l,2,4-triazol-l-yl)-2-aminopropionic acid was identi­ fied as a new metabolite of amitrole. Significant parts of radiolabel were incorporated into genuine plant products, indicating liberation of 14C 0 2 from the applied substance followed by reassimilation. Possible pathways of metabolism of amitrole within the system soil/apple tree are discussed. 
  Reference    Z. Naturforsch. 47c, 120—125 (1992); received June 18/October 24 1991 
  Published    1992 
  Keywords    Herbicide, Amitrole, Metabolism, Reassimilation, Structural Elucidation 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0120.pdf 
 Identifier    ZNC-1992-47c-0120 
 Volume    47 
20Author    Barbara Schaller, Bernd Schneider, HorstRobert SchütteRequires cookie*
 Title    Metabolism of the Herbicide Bromoxynil in Hordeum vulgare and Stellaria media  
 Abstract    The metabolism of [3,5-14C]3,5-dibromo-4-hydroxybenzonitrile (bromoxynil) was studied in Hordeum vulgare and Stellaria media. In excised barley seedlings the time course of metabolism was followed over 48 h and the distribution of radioactivity to various metabolic fractions measured. The metabolites, sepa­ rated by TLC and HPLC, were identified by chemical and spectrometric methods. Bromo-hydroquinone and 2,6-dibromohydroquinone were found, indicating partly debromination and replacement of the nitrile group by hydroxyl. The major parts of bromoxynil and of the metabolites were recovered in glucosidic conjugates. In Stellaria media the same metabolites as in Hordeum vulgare were determined. Additional­ ly, metabolites of unknown structures without bromine were detected. 
  Reference    Z. Naturforsch. 47c, 126—131 (1992); received June 18/August 21 1991 
  Published    1992 
  Keywords    Herbicide, Bromoxynil, Metabolites, Structural Elucidation, Hordeum vulgare, Stellaria media 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0126.pdf 
 Identifier    ZNC-1992-47c-0126 
 Volume    47 
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