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1991 (171)
101Author    Z. NaturforschRequires cookie*
 Title    Propagation of Voltage Transients in Arborized Neurites of Retzius Cells of the Leech in Culture  
 Abstract    Propagation o f electrical signals is studied in Retzius cells o f the leech in culture using volt­ age-sensitive fluorescent dyes at a spatial resolution o f 8 x 8 (am2 and 1 4 x 1 4 |im 2 and at a sam ­ pling interval o f 0.12 ms. The neurons are stimulated by a microelectrode impaled in the soma. Action potentials o f a halfwidth o f 2 -3 ms are triggered close to the end o f the primary neurite dissociated from the leech. They propagate back to the soma at invariant halfwidth at a veloci­ ty o f 5 0 -2 3 0 jam/ms. They pervade extended arborized secondary neurites which are grown on extracellular matrix protein. Their width is enhanced up to a factor two. The velocity is around 1 0 0 -150 (im/ms such that delays up to 3.5 ms are observed. Accordingly the neuritic trees are not isopotential. The features o f propagation are found to be incompatible with passive spread. 
  Reference    Z. Naturforsch. 46c, 687—6 (1991); received March 5 1991 
  Published    1991 
  Keywords    Leech, Neuron, Arborization, A ction Potential, Fluorescence 
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 Identifier    ZNC-1991-46c-0687 
 Volume    46 
102Author    H. G. Ru LerRequires cookie*
 Title    Directed Cell Movement with Steric Exclusion  
 Abstract    The space-dependent density o f cells is evaluated for the follow ing situation: (i) The cells are forced to make a directed movem ent (ii) the space for the cellular migration is restricted. The steady state distribution density is obtained when the drift current density equals the diffusion current density. The analogy to the Boltzmann statistics is shown. In a further step the cellular volume is introduced. For this case the density distribution is described in analogy to the Fermi statistics. The necrotactic response o f granulocytes is used to verify the model. 
  Reference    Z. Naturforsch. 46c, 697—7 (1991); received March 19 1991 
  Published    1991 
  Keywords    Chemotaxis, G alvanotaxis, Necrotaxis, Steric Interaction 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0697.pdf 
 Identifier    ZNC-1991-46c-0697 
 Volume    46 
103Author    Z. NaturforschRequires cookie*
 Title    N o Correlation between Plasmid Content and Ability to Reduce N itrate in W ild-Type Strains o f Rhodobacter capsulatus  
 Abstract    Patterns o f endogenous plasmids and nitrate reduc­ tase activities were analyzed in the phototrophic bacte­ rium Rhodobacter (Rb.) capsulatus. From 10 strains in­ vestigated (including a UV-induced plasmidless nit~ mu­ tant), 4 were unable to grow photosynthetically with nitrate as N-source and lacked nitrate reductase activity (nit strains). Irrespective o f the nit phenotype, all 
  Reference    Z. Naturforsch. 46c, 703 (1991); received May 10 1991 
  Published    1991 
  Keywords    Nitrate, Plasmid, Photosynthetic Bacteria, Rhodobacter capsulatus 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0703_n.pdf 
 Identifier    ZNC-1991-46c-0703_n 
 Volume    46 
104Author    C. Hristiane, T. Em Pête, M. Ichel Devys, M. Ichel BarbierRequires cookie*
 Title    Growth Inhibitions on Human Cancer Cell Cultures with the Indole Sulphur-Containing Phytoalexins and Their Analogues  
 Abstract    Cell growth inhibitions on human cancer cell cultures were determined for the indole sulphur-containing phy­ toalexins cyclobrassinin, brassilexin (previously isolated from vegetables o f the Cruciferae family) and their syn­ thetic analogues 5-methoxybrassilexin and hom ocyclo-brassinin. The most biologically active o f these products is brassilexin (L D 50 = 8 (ig/ml). 
  Reference    Z. Naturforsch. 46c, 706 (1991); received January 21 1991 
  Published    1991 
  Keywords    Growth Inhibition, Cancer Cells, Phytoalexins, Cruci­ fer ae 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0706_n.pdf 
 Identifier    ZNC-1991-46c-0706_n 
 Volume    46 
105Author    BerndW. Issinger, O. Lf, Hiesel, W. Erner Schobel, M. Ichael, U. Nseld, Axel Brennicke, W. Olfgang SchusterRequires cookie*
 Title    Duplicated Sequence Elements and Their Function in Plant Mitochondria  
 Abstract    A considerable portion o f the plant mitochondrial D N A is derived from genom e internal duplications. Many o f these amplified sequences determine functions o f transcription and processing. A m ong these are promoter regions, sequences defining the 3' ends o f stable m R N A s, potential R NA processing sites and intron domains. Sim ultaneously, som e o f these repeated sequences can be active sites o f recombination in plant mitochondria. Such duplicat­ ed control regions may simplify coordinate expression o f different genes. In v ite d T re n d s A rticle 
  Reference    Z. Naturforsch. 46c, 709 (1991); received July 22 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0709 
 Volume    46 
106Author    S. Schneider, H. Tiltscher, R. Fischer, D. H. ScheerRequires cookie*
 Title    UV-VIS Absorption Spectra at High Pressure of C-Phycocyanin and Allophycocyanin from Mastigocladus laminosus  
 Abstract    The behaviour o f monom ers and trimers o f C-phycocyanin and allophycocyanin under high pressure is studied by U V-V IS absorption spectroscopy. It is found that fast variations o f pres­ sure (Ap > 500 bar) and/or temperature are accompanied by significant changes in the absorp­ tion spectra (intensity and/or spectral shift). The induced differences disappear, however, in part, when the samples are left for several minutes at the final pressure (relaxation effect). The observed spectral variations are different from those connected with a change in state o f aggre­ gation and could therefore be due to small m odifications o f the chromophore-protein arrange­ ment. 
  Reference    Z. Naturforsch. 46c, 717 (1991); received April 29 1991 
  Published    1991 
  Keywords    gewidmet Photosynthesis, Phycobiliproteins, Light-Harvesting Pigments, Aggregation Effects, High-Pressure Spectroscopy 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0717.pdf 
 Identifier    ZNC-1991-46c-0717 
 Volume    46 
107Author    J. Berlinab, L. Fecker, C. R. Ügenhagenab, C. S. Atorc, D. S. Trackd, L. W. Itted, V. W. RaybRequires cookie*
 Title    Isoflavone Glycoside Formation in Transformed and Non-Transformed Suspension and Hairy Root Cultures of Lupinus polyphyllus and Lupinus hartwegii  
 Abstract    sides Transformed cell suspension and hairy root cultures were established by infecting seedlings o f Lupinus polyphyllus and L. hartwegii with various wild type strains o f Agrobacterium tume-faciens and A. rhizogenes. Transformation o f the cultures was confirmed either by their phyto­ hormone autotrophy, detection o f opines or southern analysis. Glueosides o f genistein and 2'-hydroxygenistein, were found to be the main secondary metabolites in normal and trans­ formed suspension cultures as well as in hairy root cultures. Although some o f the isoflavone glycosides o f the cultures were apparently new constituents o f Lupinus, they were afterwards also found in young seedlings. 
  Reference    Z. Naturforsch. 46c, 725 (1991); received April 23 1991 
  Published    1991 
  Keywords    Lupinus polyphyllus, Lupinus hartwegii, Cell Cultures, Hairy R oot Cultures, Isoflavone Gluco- 
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 Identifier    ZNC-1991-46c-0725 
 Volume    46 
108Author    J. Berlinab, C. Rügenhagena, M. Rippert, S. ErdoganRequires cookie*
 Title    Effects of Culture Conditions on Isoflavonoid Levels of Transformed and Non-Transformed Cultures of Lupinus -a Comparison of Suspension and Hairy Root Cultures  
 Abstract    Some highly productive suspension and hairy root cultures were found among several trans­ formed cultures o f Lupinus polyphyllus and L. hartwegii. A transformed suspension culture Lupo 30150 and a root culture Luha 15834 containing the highest specific isoflavone glucoside content were characterized and compared with normal phytohormone-dependent lines with respect to product stability as well as to their responsiveness to external triggers, e.g. response to changes in the medium. While phytohorm one-dependent suspension cultures lost their ini­ tial ability to form increased levels o f isoflavonoids on phytohormone-free medium, the trans­ formed phytohorm one-independent suspension Lupo 30150 remained a highly productive line, despite the fact that its specific levels decreased to 60% o f the initial values during several years in liquid medium. Highest stability o f product patterns and levels were noted for the transformed root culture. Phytohorm ones had little effect on growth and isoflavonoid levels in suspension cultures, while they reduced both strongly in root cultures. In the presence o f 2,4-D the root culture changed into an aggregated low producing suspension culture from which the root state was recovered on phytohorm one-free medium. As long as the root state was main­ tained, isoflavonoid levels could not be distinctly improved by media variation while specific isoflavonoid levels o f suspensions were increased by stress factors such as phosphate depletion. When suspensions were transferred to fresh medium phenylalanine ammonia-lyase was greatly induced within 24 h, while the activity remained nearly unchanged in root cultures. 
  Reference    Z. Naturforsch. 46c, 735—7 (1991); received April 23 1991 
  Published    1991 
  Keywords    Lupinuspolyphyllus, Lupinus hartwegii, Transformation, Hairy R oot Cultures, Isoflavonoids 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0735.pdf 
 Identifier    ZNC-1991-46c-0735 
 Volume    46 
109Author    Paul-G Erhard Gülza, R.B N Prasadb, Edith MülleraRequires cookie*
 Title    Surface Structure and Chemical Composition of Epicuticular W axes during Leaf Development of Tilia tomentosa Moench  
 Abstract    Tilia tomentosa M oench., Tiliaceae, Wax Surface Structure, Epicuticular Wax C om position, SEM The very young leaflets o f silver lime trees (T ilia tom tentosa), just unfolding from buds, con ­ tained a continuous wax layer without any wax sculptures. The wax on young leaves is quite different in yield and com position than that o f mature leaves. After unfolding o f leaves a very dynamic biosynthesis o f most wax lipids was started. Fifteen days after leaf unfolding the de novo biosynthesis o f ß-amyrenyl acetate and later on o f aldehydes could be detected for the first time. The biosynthesis o f wax com ponents in silver lime leaves was finished at the end o f June and the wax remained nearly constant in amount and com position during the remaining season. At the same time, when ß-amyrenyl acetate was found for the first time, wax sculptures were observed in silver lime leaf waxes coming out o f the continuous wax layer, exclusively on the upper leaf side. These wax sculptures increased in quantity in the next weeks and resulted in a crystalloid shape o f m ost solitaire quadrangular rodlets. These crystals were remained all over the season and were formed from ß-amyrenyl acetate, the dominating main wax com p o­ nent {ca. 49% wax). 
  Reference    Z. Naturforsch. 46c, 743—7 (1991); received May 8/June 18 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0743 
 Volume    46 
110Author    HansjörgA W Schneider-Poetsch, Christoph Sensen, Sabine HaneltRequires cookie*
 Title    Are Bacterial Sensory Systems Models for Phytochrome Action? Hydrophobic Cluster Analysis of the Phytochrome Module Related to Bacterial Transmitter Modules  
 Abstract    C-terminal amino acid sequences o f two phytochrom es sharing less than 40 per cent hom ol­ ogy and two transmitter modules o f bacterial sensor proteins that share hom ologies with phy­ tochromes were examined by hydrophobic cluster analysis. Striking coincidences in distribu­ tion, size, shape and orientation o f hydrophobic and hydrophilic domains o f the bacterial transmitter modules and phytochrome sequences were revealed. The results corroborate the view that the folding o f the hom ologous regions o f the two groups o f proteins is similar. Since the mode o f action o f phytochrome is not known, the structural coincidences may be indica­ tive o f how phytochrome transmits signals, although distinct differences should not be over­ looked. Some coinciding structural features in phytochrom es and bacterial sensors may tenta­ tively be extracted from secondary structure predictions. 
  Reference    Z. Naturforsch. 46c, 750—7 (1991); received M ay 21 1991 
  Published    1991 
  Keywords    Phytochrome Action, Bacterial Sensors, Transmitter M odules, Hydrophobie Cluster Analysis, Structure Predictions 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0750.pdf 
 Identifier    ZNC-1991-46c-0750 
 Volume    46 
111Author    Siegfried Engelbrechta, Jennifer Reedb, Francois Peninc, DanieleC G Autheronc, W. Olfgang Jungea, C. F.Requires cookie*
 Title    Subunit 8 o f Chloroplast F0Fr ATPase and O SC P of Mitochondrial F0Fr ATPase: a Comparison by CD-Spectroscopy  
 Abstract    C D spectra have been recorded with subunit 5 from chloroplast C F0CF, and with OSCP from mitochondrial M F0M F ,. These subunits are supposed to act similarly at the interface between proton transport through the F0-portion and ATP-synthesis in the F,-portion o f their respective F0F,-A TPase. Evaluation o f the data for both proteins revealed a very high a-helix content o f —85% and practically no ß-sheets. Despite their low hom ology on the primary structure level (23% identity) and their different electrostatic properties (pl-values differ by 3 units), spinach 8 and porcine OSCP are indistinguishable with respect to their secondary structure as measured by CD. Prediction and analysis o f consensual a-helices even in poorly conserved regions indicate a high degree o f structural similarity between chloroplast 8 and OSCP. In view o f the topology and function o f 8 and OSCP in intact F0F, these findings are interpreted to indicate the dominance o f secondary and tertiary structure over the primary structure in their supposed function between proton flow and ATP-synthesis. 
  Reference    Z. Naturforsch. 46c, 759 (1991); received May 31 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0759 
 Volume    46 
112Author    Bengt Svensson, Imre Vass, Stenbjörn StyringRequires cookie*
 Title    Sequence Analysis of the D 1 and D 2 Reaction Center Proteins of Photosystem II  
 Abstract    A com pilation o f 38 sequences for the D1 and 15 sequences for the D 2 reaction center pro­ teins o f photosystem II is presented. The sequences have been compared and a similarity index that takes into account the degree o f conservation and the quality o f the changes in each posi­ tion has been calculated. The similarity index is used to identify and describe functionally im­ portant domains in the D 1 /D 2 heterodimer. Comparative hydropathy plot are presented for the aminoacid sidechains that constitute the binding domain o f the tyrosine radicals, Tyrz and TyrD, in photosystem II. The structure around Tyrz is more hydrophilic than the structure around TyrD. The hydrophilic residues are clustered in the part o f the binding pocket for Tyrz that is turned towards the lumenal side o f the thylakoid membrane. M ost prominent is the presence o f two conserved carboxylic am inoacids, D l-A sp 170 and D l-G lu 189. Their respec­ tive carboxyl-groups com e close in space and are proposed to constitute a metal binding site together with D l-G ln 165. The distance between the proposed metal binding site and the cen­ ter o f the ring o f Tyrz is approximately 7Ä . The cavity that constitutes the binding site for TyrD is com posed o f residues from the D 2 protein. Its character is more hydrophobic than the Tyrz site and the environment around TyrD lacks the cluster o f putative metal binding side­ chains. 
  Reference    Z. Naturforsch. 46c, 765 (1991); received March 13 1991 
  Published    1991 
  Keywords    Photosystem II, D1 Protein, D 2 Protein, Tyrosine, M anganese, Reaction Center 
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 Identifier    ZNC-1991-46c-0765 
 Volume    46 
113Author    B. Lotina-Hennsena, J. L. Roque-Reséndiza, M. Jiménezb, M. Aguilar0Requires cookie*
 Title    Inhibition of Oxygen Evolution by Cacalol and Its Derivatives  
 Abstract    Inhibition o f Oxygen Evolution, Cacalol and Its Derivatives, Hill Reaction The inhibition o f ATP synthesis, proton uptake and electron transport (basal, phosphory-lating and uncoupled) from water to methylviologen indicates that cacalol and its derivatives act as electron transport inhibitors. Since on one hand photosystem I is not affected and elec­ tron transport from DPC to QA is midly affected and on the other hand the electron transport from water to DCIP, and water to silicomolibdate are inhibited, we conclude that the site o f inhibition o f cacalol is located at the oxygen evolution level. Cacalol derivatives inhibit elec­ tron flow between P680 to QA and probably also the Q B site. 
  Reference    Z. Naturforsch. 46c, 777—7 (1991); received December 11 1990/March 27 1991 
  Published    1991 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0777.pdf 
 Identifier    ZNC-1991-46c-0777 
 Volume    46 
114Author    Klaus-Dieter Spindler, Brigitte Funke-HöpfnerRequires cookie*
 Title    N-Acetyl-ß-D-hexosaminidases of the Brine Shrimp Artemia: Partial Purification and Characterization  
 Abstract    Artem ia, N-Acetyl-ß-D-hexosaminidases, Isoenzymes, Kinetics N-Acetyl-ß-D-hexosaminidases (EC 3.2.1.52) from Artem ia nauplii were isolated and char­ acterized. Three different enzymes I, II, and II2 were separated according to their behaviour on anion exchange chromatography and gel filtration colum ns. Their apparent molecular masses were 83,000 ± 7000, 110,000 ± 10,000 and 56,000 ± 5000 Da with corresponding S-values o f 8.6, 11.9 and 7.9. All three enzymes also differ in their apparent pH-optima (5.1, 4.5 and 6.1) and they all bind to concanavalin A. The three enzymes have about the same affinities (app. Km between 0.16 and 0.72 mmol/1) for the three substrates (p-nitrophenyl-N-acetyl-ß-D-glucosamine or /?-nitrophenyl-N-acetyl-ß-D-galactosamine and N ,N'-diacetyl-chitobiose) and are therefore N-acetyl-ß-D-hexosamini-dases. In contrast, the three enzymes behave quite differently, both in terms o f their inhibitor constants and the type o f inhibition. The substrates inhibit both enzymes II, and II2 but not enzyme I. On the other hand, N-acetyl-ß-D-galactosamine inhibits enzyme I in a non-com peti­ tive way but not enzymes II, and II2. All three enzymes are inhibited by the end product N-acetyl-ß-D-glucosamine, enzyme I in a competitive manner, both enzymes II, and II2 in a non-com petitive way. 2-Acetam ido-2-deoxy-D-galactonolactone is a strong inhibitor for en­ zyme I (K l = 13 j.tmol/1) with much lower affinities towards enzymes II, and II, (K t = 0.63 and 1.03 mmol/1). All three enzymes are inhibited in a dose-dependent way and completely reversi­ ble by a-m ethyl-mannoside. 
  Reference    Z. Naturforsch. 46c, 781—7 (1991); received March 18/July 8 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0781 
 Volume    46 
115Author    Ch Heyde, M. WenzelRequires cookie*
 Title    Schweres Wasser (D 20 ) als Protektivum proteinhaltiger Arzneimittel. Beispiel: humane Cholinesterase Protein Drugs Stabilized by Heavy W ater (D 20 ). For Example: Hum an Cholinesterase  
 Abstract    Looking for a possible protective effect o f heavy water on proteins, Cholinesterase and lac­ tate dehydrogenase in com bination with D 20 and further protective substances were exposed to a temperature o f 60 °C (for 10 min) and about 45 °C (for several days). In combination with glycerine there resulted an additive protective effect; with NaCl and/or albumin being added the individual effects raised to a higher level. In the cold D 20 protects Cholinesterase only against acid denaturation, but in com bination with warmth also against basic dena-turation. 
  Reference    Z. Naturforsch. 46c, 789—7 (1991); eingegangen am 19. Februar 1991 
  Published    1991 
  Keywords    Heavy Water, Protein Drugs, Stabilization, Com binations, Cholinesterase 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0789.pdf 
 Identifier    ZNC-1991-46c-0789 
 Volume    46 
116Author    GeraldR. Stephenson, Tuvia Yaacoby, Dichlormid Thiocarbamates, ChloroacetamidesRequires cookie*
 Title    Milestones in the Development of Herbicide Safeners  
 Abstract    The concept o f using chemical safeners to improve herbicide selectivity became widely known in 1969 with the introduction o f naphthalic anhydride (N A) to improve the tolerance o f maize to thiocarbamate herbicides. Soon thereafter dichlormid was also developed as a safener for thiocarbamates in maize. At present there are at least eight different chemical safeners that have been developed commercially. Many o f these safeners have been m ost effec­ tive for chloroacetamide or thiocarbamate herbicides in m onocotyledonous crops such as maize or sorghum. Some are like dichlormid and have been developed as physiologically selec­ tive safeners that can be combined in the formulation with the herbicides. Others, like N A , are either less selective or less active in the soil and must be used as dressings on the crop seed. M ost o f the presently used safeners are for soil active herbicides. The challenge for the future will be to develop safeners that are effective for the newer postemergence herbicides in dicoty­ ledonous as well as m onocotyledonous crops. 
  Reference    Z. Naturforsch. 46c, 794—7 (1991); received March 26 1991 
  Published    1991 
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 Identifier    ZNC-1991-46c-0794 
 Volume    46 
117Author    K. Öm Ívesa, K. Riton, K. HatziosbRequires cookie*
 Title    Chemistry and Structure-Activity Relationships of Herbicide Safeners  
 Abstract    The discovery and commercial success of safeners against thiolcarbamate herbicide injury to corn has stimulated a rapid progress and opened new possibilities for further research and development in the last decade. Compounds with new chemistry, increased efficacy, and a broader selectivity spectrum were synthesized and developed for agricultural use. Structure-activity relationship studies helped to optimize their chemical properties and to understand their biological modes of action. Several examples indicate close similarity between chemical structures possessing herbicidal and safener properties. In some cases this differentiation may be marginal, as shown in crops pretreated with low herbicide doses leading to safening effects. In other examples, however, structural optima for safening and herbicidal efficacy can be clearly differentiated. 
  Reference    Z. Naturforsch. 46c, 798—804 (1991); received March 26 1991 
  Published    1991 
  Keywords    Safeners, Chemical Properties, Structure-Activity Relationships 
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 Identifier    ZNC-1991-46c-0798 
 Volume    46 
118Author    FerencD. UtkaRequires cookie*
 Title    Bioactive Chemical Bond Systems in Safeners and Prosafeners  
 Abstract    Acetals and ketals involving a dichloromethyl group on their central carbon atom were found to be active or highly active as safeners of corn against thiocarbamate and chloroacet-anilide herbicide injury. A mechanism for the biotransformation of these compounds as pro­ safeners to the actual dichloroacetic ester safeners is proposed. Similarly, S-and N-analogues of the cyclic acetals (ketals) which show safener activity can also be considered as prosafeners because they can be converted in the biophase by the same mechanism into actual safeners such as dichloroacetic thiolesters or dichloroacetamides sup­ porting the bioactivation hypothesis. Characteristic bioactive chemical bond systems in safeners and prosafeners are suggested. 
  Reference    Z. Naturforsch. 46c, 805 (1991); received March 26 1991 
  Published    1991 
  Keywords    Safeners, Prosafeners, Acetals, Ketals, MG-191 
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 Identifier    ZNC-1991-46c-0805 
 Volume    46 
119Author    Zsigmond Ekler, FerencD. UtkaRequires cookie*
 Title    Chemical Reactivity and Safener Activity of Acetal Compounds  
 Abstract    Although detailed examinations have been published on structure-activity relationships of herbicide safeners, only a few data are available on chemical reactivity-safener activity rela­ tionships. Chemical reactivity o f acetamide type compounds as well as their safener activity against thiocarbamate herbicides change with the number o f chlorine substituents in the order: non-chlorinated < monochloro < dichloro. Several compounds of another chemical group, acetals (e.g. MG-191, 2-dichloromethyl-2-methyl-l,3-dioxolane), are also effective safeners for thiocarbamate herbicides. According to our growth room studies, the safener activity o f ace­ tals also increases with increasing chlorine content up to two chlorine atoms on the same car­ bon. A number of differently chlorinated acetals have been synthesized and their acid-cata­ lyzed hydrolysis rate determined in order to establish a relationship between their bioactivity and chemical reactivity. The hydrolysis rate order of acetals containing no, one or two chlorine atoms: non-chlorinated > monochloro > dichloro, is just the opposite than what has been found for acetamides. Thus, safener activity of acetals increases with decreasing chemical reac­ tivity. The opposite reactivity order of acetamides and acetals can be explained by the different mechanisms of their hydrolysis. Dichloroacetals may not be effective safeners in their original structure. In plants, however, they can be biologically activated to active safeners by a trans­ formation other than hydrolysis. 
  Reference    Z. Naturforsch. 46c, 810—814 (1991); received March 26 1991 
  Published    1991 
  Keywords    Acetals, Hydrolysis, Herbicides, Herbicide Safeners, Zea mays (L) 
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 Identifier    ZNC-1991-46c-0810 
 Volume    46 
120Author    György Matolcsy, Ágota Tom, Antal GimesiRequires cookie*
 Title    Dithiocarbamate Derivatives as Herbicide Safeners  
 Abstract    Herbicide Safeners, Dithiocarbamates, Oxazaspiro[4.5]decane, Corn (Zea mays L.) The growing environmental and toxicological concern about the dichloroacetamide type herbicide safeners prompted us to search for alternative safener types. Based on analogy con­ siderations, a random screening of structurally unrelated bivalent sulphur compounds was performed, followed by successive structure optimization phases representing both speculative and empirical elements. Dithiocarbamate ester type compounds derived from 1,4-exaza-spiro[4.5]decane revealed highest protecting potency both agains thiolcarbamate and chlor-acetanilide herbicides in corn (Zea mays L.), with the benzylic and allylic esters being the most active. 
  Reference    Z. Naturforsch. 46c, 815—818 (1991); received April 4 1991 
  Published    1991 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0815.pdf 
 Identifier    ZNC-1991-46c-0815 
 Volume    46 
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