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'Inhibitors' in keywords Facet   Publication Year 1981  [X]
Facet   section ZfN Section C  [X]
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1981[X]
1Author    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 
2Author    Toshihisa Ohshima, Gerhart DrewsRequires cookie*
 Title    Isolation and Partial Characterization of the Membrane-Bound NADH Dehydrogenase from the Phototrophic Bacterium Rhodopseudomonas capsulata  
 Abstract    Chem otrophically grown cells of Rhodopseudomonas capsulata contain at least three different pyridine nucleotide dehydrogenases, i) a soluble, found in the supernatant (144000 x g) o f cell free extracts, N AD H-dependent, ii) a mem brane-bound, N AD H -dependent, and iii) a soluble, found in the supernatant N AD PH dependent. i The m em brane-bound N A D H dehydrogenase (E.C. 1.6.99.3) has been solubilized by sodium deoxycholate treatm ent of m em branes and purified 75 fold by column chrom atography on Sephadex G-150 and DEAE cellulose in the presence of sodium cholate. The native enzyme has an apparent molecular mass (M r) o f 97 000, containing polypeptides of Mr of about 15 000. The pH optim um was at 7.5. The enzyme was specific for NADH. The Michaelis constant for NADH and DCIP were 4.0 and 63 hm, respectively. The enzyme was inactivated by FM N, riboflavin and NADH. In contrast, the soluble N ADH-dehydrogenase (i) was activated by FMN. 
  Reference    Z. Naturforsch. 36c, 400 (1981); received February 23/M arch 16 1981 
  Published    1981 
  Keywords    NADH Dehydrogenase, Purification, Localization, Inhibitors, Rhodopseudomonas capsulata 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0400.pdf 
 Identifier    ZNC-1981-36c-0400 
 Volume    36 
3Author    Klaus Pfister, H. Artm, K. Lichtenthaler, G. Ünther Burger, Hans Musso, M.Anuel ZahnRequires cookie*
 Title    The Inhibition of Photosynthetic Light Reactions by Halogenated Naphthoquinones  
 Abstract    Halogenated naphthoquinones act as inhibitors o f photosynthetic electron flow. I50 concentra­ tion for inhibition of methylviologen reduction were found to range between 2 x 10-5 m to 2 x 10-6 M. Comparing their effects on several partial reactions o f electron flow, the inhibition site o f the naphthoquinones was found to be at the reducing site o f PS II. Studies o f fluorescence transients in presence o f halogenated naphthoquinones give further evidence for a site action similar to that o f diuron and different to that of DBMIB. All naphthoquinones act as quenchers o f chlorophyll fluorescence with pure chlorophyll a, and with much higher efficiency in green algae and chloroplasts. It is concluded, that the halogenated naphthoquinones act similar to PS II-inhibitors like diuron, but do not share a common binding site at the PS II-complex. Implications of a possible involvement of phylloquinone K 1 in photosynthetic electron transport are discussed. The synthesis o f 2-chloro-as well as 2-bromo-3-isopropyl-1,4-naphthoquinone is described. 
  Reference    Z. Naturforsch. 36c, 645—655 (1981); received April 271981 
  Published    1981 
  Keywords    Chlorophyll Fluorescence, Electron Transport, Inhibitors, Naphthoquinones, Photosynthesis, Quenchers 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0645.pdf 
 Identifier    ZNC-1981-36c-0645 
 Volume    36 
4Author    Laurie Tompkins, JeffreyC. HallRequires cookie*
 Title    Drosophila M ales Produce a Pheromone which Inhibits Courtship  
 Abstract    Normal Drosophila males produce a volatile pheromone which inhibits courtship. This chemical cue is not identical to the pheromone made by mated female flies, which also inhibits male sexual behavior. Mutant olfC males, which fail to respond to several organic compounds, are not inhibited by the pheromone made by males; hence, unlike normal sexually mature males, olfC males court each other vigorously. 
  Reference    Z. Naturforsch. 36c, 694—696 (1981); received March 121981 
  Published    1981 
  Keywords    Drosophila melanogaster, Sex Pheromone, Sexual Behavior, Inhibitor, Behavioral Mutant 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0694_n.pdf 
 Identifier    ZNC-1981-36c-0694_n 
 Volume    36