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1993 (1)
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1Author    K. K. Arl-Josef, UnertRequires cookie*
 Title    The Diphenyl-Ether Herbicide Oxyfluorfen: A Potent Inducer of Lipid Peroxidation in Higher Plants  
 Abstract    Measurements o f ethane and ethylene as indices o f in vivo lipid peroxidation and o f chemically-induced stress, respectively, were done on mustard seedlings (Sinapis alba), treated with oxy-fluorfen[2-chloro-l-(3-ethoxy-4-nitrophenoxy)-4-(trifluorom ethyl)benzene]. W hen seedlings were exposed to low light intensity o f 14 W /m 2, only stress-ethylene production but not per­ oxidative ethane evolution was significantly higher over 1 0 days in herbicide-treated seedlings than in the untreated control. Exposure to high light intensity o f 390 W /m 2 did not increase stress-ethylene production in oxyfluorfen-treated plants after 24 h. Lipid peroxidation, however, measured as ethane evolution, was substantially higher after 24 h in herbicide-treated plants, exposed to high light intensity, than in the control, and peroxidation was directly related to strong oxidation o f antioxidants and to severe membrane dam age. 
  Reference    Z. Naturforsch. 39c, 476—481 (1984); received September 15 1983 
  Published    1984 
  Keywords    Herbicide, Diphenyl Ether, Peroxidation, Antioxidants 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0476.pdf 
 Identifier    ZNC-1984-39c-0476 
 Volume    39 
2Author    Bernhard Huchzermeyer, Andreas LöhrRequires cookie*
 Title    Diphenyl Ether Herbicides, a Tool to Elucidate the Mechanism of Photophosphorylation  
 Abstract    At least two different classes of A DP binding sites on chloroplast coupling factor are de­ scribed in the literature. High-affinity sites are assumed to entail regulatory functions while low-affinity sites are involved in catalysis. Diphenyl ether herbicides, acting as energy transfer inhibitors, interfere with nucleotide ex­ change on both categories of A D P binding sites. Their inhibitory potency varies depending on their substitution. We found that each diphenyl ether assayed revealed identical / 50 values for inhibition of nucleotide interaction with both classes of binding sites. We show here that diphenyl ether inhibition of energytransfer is primary based upon the interference with A DP binding to high-affinity binding sites. Thereby the control of proton permeability through the coupling factor complex is affected. Moreover, we found that the three ß-subunits are not absolutely fixed in one conformational state: After covalently block­ ing the high-affinity site by an azido-label, a new ß-subunit. 
  Reference    Z. Naturforsch. 45c, 552—557 (1990); received October 10 1989 
  Published    1990 
  Keywords    Diphenyl Ethers, Energy-Transfer Inhibition, Nitrofen, Photophosphorylation, Coupling Factor 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0552.pdf 
 Identifier    ZNC-1990-45c-0552 
 Volume    45 
3Author    DonaldE. MorelandRequires cookie*
 Title    Research on Biochemistry of Herbicides: An Historical Overview  
 Abstract    Otto Warburg, the father o f cellular bioenergetics, seems to have been the first investigator to report on inhibition o f a plant biochemical reaction by a progenitor o f a selective herbicide. The year was 1920 and the com pound was phenylurethane (ethyl N-phenylcarbam ate or EPC). Warburg found that it strongly inhibited photosynthesis in Chlorella. EPC did not de­ velop into a commercial herbicide, but the isopropyl derivatives (propham and chlorpropham) which were introduced in the late 1940s became selective herbicides. The phenylureas (m onu-ron and diuron) were introduced in the early 1950s and shortly thereafter, interference with the Hill reaction by both phenylureas and phenylcarbamates was reported. During the latter part o f the 1950s, into the 1960s, and even now, additional herbicidal chemistry was and is being announced that interferes with the Hill reaction. Duysens, in 1963, identified the site o f action o f diuron, i.e., on the acceptor side o f PS II. Corwin Hansch, in 1966 introduced the SA R or Q SAR concept in which inhibitory action o f Hill inhibitors was related to various chemical and physical parameters. Because o f differential responses to partial, thylakoid-associated reactions, the Hill inhibi­ tors were subsequently divided into two groups: pure electron transport inhibitors (phenyl­ ureas, s-triazines, triazinones, and uracils) and inhibitory uncouplers (acylanilides, dinitro-phenols, benzim idazoles, dinitroanilines, and benzonitriles). The inhibitory uncouplers (dino-seb-types), unlike the diuron-types, uncoupled photophosphorylation by interacting with the coupling factor com plexes in both chloroplasts and intact mitochondria. Additionally, the bi-pyridyliums were shown to be reduced by PS I, hence, diverted electrons from the native ac­ ceptor. Field observations o f triazine resistance were reported in 1970 and resistance was subse­ quently demonstrated at the thylakoid level. Application o f the techniques o f genetic engineer­ ing and biotechnology resulted in identification o f the 32 kD a herbicide-binding protein and determination o f its amino acid sequence. Crystallization and X-ray examination o f the p h oto­ synthetic reaction center from Rhodopseudomonas by Michel et al. in the mid-1980s provided new models to account for interactions o f herbicides with the D -l protein. During the 1980s, herbicides were identified that interfered with biochemical machinery in chloroplasts that is not involved in electron transport and light harvesting: inhibition o f lipid biosynthesis by aryloxyphenoxypropionates and cyclohexanediones, aromatic amino acid bio­ synthesis by glyphosate, branched chain amino acid biosynthesis by sulfonylureas and imida-zolinones, carotenoid biosynthesis by pyridazinones, and porphyrin biosynthesis by diphenyl-ethers and oxadiazoles. The current status o f research in most, if not all, o f the above areas was reported through oral and poster presentations at this Omiya Symposium. 
  Reference    Z. Naturforsch. 48c, 121—131 (1993); received October 10 1992 
  Published    1993 
  Keywords    Herbicide Targets, Photosynthesis, Am ino Acid Biosynthesis, Lipid Biosynthesis, Diphenyl Ethers 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0121.pdf 
 Identifier    ZNC-1993-48c-0121 
 Volume    48