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21Author    M. Suwalsky, M. A. Espinoza, M. Bagnara, C. P. SotomayorRequires cookie*
 Title    X-Ray and Fluorescence Studies on Phospholipid Bilayers. IX. Interactions with Pentachlorophenol  
 Abstract    Pentachlorophenol (PCP) is a widely used and highly toxic fungicide. Its toxicity is mainly expressed at the cell membrane level. It is, therefore, o f interest to test its ability to alter the lipid bilayer organization. The present study was performed by X-ray diffraction techniques on dimyristoylphosphatidylethanolam ine (D M PE) and dim yristoylphosphatidylcholine (D M P C) bilayers and by fluorescence on DM PC liposomes. These two phospholipids are re­ spectively found at the inner and outer monolayers o f human erythrocyte membranes. Each type o f phospholipid was made to interact with different concentrations o f the sodium form o f PCP in absence and in presence o f water. It was found that PCP significatively affected the structure o f both phospholipids, being the damage much higher in DM PC bilayers. 
  Reference    Z. Naturforsch. 45c, 265 (1990); received September 18 1989 
  Published    1990 
  Keywords    X -R ay Diffraction, Fluorescence, Phospholipid Bilayers, Pentachlorophenol, Toxicity 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0265.pdf 
 Identifier    ZNC-1990-45c-0265 
 Volume    45 
22Author    MarcelA K Jansen3, Shmuel Malkinb, Marvin EdelmanaRequires cookie*
 Title    Differential Sensitivity of 32 kDa-D 1 Protein Degradation and Photosynthetic Electron Flow to Photosystem II Herbicides  
 Abstract    Degradation of the 32 kDa-D 1 protein, a photosystem II reaction centre component, was studied as a function of linear electron flow in visible light in the presence of various photosys­ tem II herbicides. Under these conditions, herbicide specific effects on protein degradation were clearly evident. 32 kDa-D 1 protein degradation and electron flow between Q a and Q b proved to be only partially correlated. We conclude that inhibition of protein degradation by PS II herbicides in visible light is not simply correlated to displacement of Q b. 
  Reference    Z. Naturforsch. 45c, 408—411 (1990); received December 12 1989 
  Published    1990 
  Keywords    Diuron, Bromoxynil, Dinoseb, Oxygen, Evolution, Chlorophyll, Fluorescence 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0408.pdf 
 Identifier    ZNC-1990-45c-0408 
 Volume    45 
23Author    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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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0687.pdf 
 Identifier    ZNC-1991-46c-0687 
 Volume    46 
24Author    V. Ictor, B. Curw, G. Ert, S. Chan Sk Er, O. Scar, J. De, V. Os, J. S. Van RensenRequires cookie*
 Title    Comparison of Photosynthetic Activities in Triazine-Resistant and Susceptible Biotypes of Chenopodium album  
 Abstract    Triazine-resistant and susceptible Chenopodium album plants were grown at low and at high light irradiances. A t the lower light irradiance the dry m atter production of the resistant and the susceptible plants were almost similar. At the higher irradiance the resistant biotype had a significantly lower production. Fluorescence studies showed that the photochemical yield and the photosystem II electron transport rate were lower in the resistant biotype. It could be demonstrated in intact leaves that the lower productivity of the resistant biotype is caused by a higher sensitivity to photoinhibition. However, when studying effects of photoinhibition on electron flow and photophosphorylation in isolated thylakoids o f the two biotypes, no signifi­ cant differences between resistant and susceptible plant materials were observed. It is suggest­ ed that the difference between resistant and susceptible biotypes connected with processes pro­ tective against photoinhibition in intact leaves, are lost during the isolation of thylakoids. 
  Reference    Z. Naturforsch. 48c, 278 (1993); received November 26 1992 
  Published    1993 
  Keywords    Chloroplasts, Triazine-Resistance, Photosystem II, Photoinhibition, Fluorescence 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0278.pdf 
 Identifier    ZNC-1993-48c-0278 
 Volume    48 
25Author    NavassardV. Karapetyanab, Ute Windhövel3 ', AlfredR. Holzwarthc, Peter BögeraRequires cookie*
 Title    Physiological Significance of Overproduced Carotenoids in Transformants of the Cyanobacterium Synechococcus PCC7942  
 Abstract    The functional location of carotenoids in the photosynthetic apparatus of -crtB and -pys transformants of the cyanobacterium Synechococcus PCC7942 was studied and compared with a control strain -pF P l-3. These transformants overproduce carotenoids due to the insertion of an additional foreign phytoene synthase gene. A higher carotenoid content was found for -crtB and -pys transformants both in whole cells and isolated membranes; the -crtB transformant was also enriched with chlorophyll. 77-K fluorescence emission and excita­ tion spectra of the phycobilin-free membranes were examined for a possible location of overproduced carotenoids in pigment-protein complexes in situ. A similar ratio of the ampli­ tudes of fluorescence bands at 716 and 695 nm emitted by photosystems I and II, found for the three strains, indicates that the stoichiometry between photosystems of the transformants was not changed. Overproduced carotenoids are not located in the core antenna of photosys­ tem I, since 77-K fluorescence excitation spectra for photosystem I of isolated membranes from the studied strains do not differ in the region of carotenoid absorption. When illumi­ nated with light of the same intensity but different quality, absorbed preferentially by either carotenoids, chlorophylls or phycobilins, respectively, oxygen evolution was found always higher in the transformants -crtB and -pys than in -p F P l-3 control cells. Identical kinetics of fluorescence induction of all strains under carotenoid excitation did not reveal a higher activity of photosystem II in cells enriched with carotenoids. It is suggested that overpro­ duced carotenoids of the transformants are not involved in photosynthetic light-harvesting; rather they may serve to protect the cells and its membranes against photodestruction. 
  Reference    Z. Naturforsch. 54c, 191—198 (1999); received December 18 1998 
  Published    1999 
  Keywords    Carotenoid, Chlorophyll, Cyanobacterium, Fluorescence, Oxygen Evolution 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0191.pdf 
 Identifier    ZNC-1999-54c-0191 
 Volume    54 
26Author    Zoltán Takács, Zsolt Csintalan, Zoltán TubaRequires cookie*
 Title    Responses of the Lichen Cladonia convoluta to High C 0 2 Level and Heavy Metal Treatment  
 Abstract    Despite of the downward acclimation of photosynthesis in C. convoluta, increased net photosynthesis and carbon balance can be anticipated in response to elevated atmospheric C 0 2 level. C 0 2 exchange measurement seems to be m ore indicative when detecting heavy metal stress than fluorescence parameters. Among these, the relative fluorescence decrease ratio (R F d 690) shows damage first, suggesting that the primary attack site for heavy metal ions is C 0 2 fixation and reaction centres are harmed last. Long-term elevated C 0 2 amelio­ rates partly this damage by improving C-balance to a greater extent in the heavy-metal stressed lichens. 
  Reference    Z. Naturforsch. 54c, 797—8 (1999); received November 15 1998/M arch 5 1999 
  Published    1999 
  Keywords    Cadmium, Lead, Fluorescence, Respiration, Photosystem II 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0797.pdf 
 Identifier    ZNC-1999-54c-0797 
 Volume    54 
27Author    I. Timtcheva, P. Nikolov, St Minchevand, N. SofronievRequires cookie*
 Title    Luminescence Properties of Some 4-or 5-Aminosubstituted Indan-13-Diones  
 Abstract    The photophysical characteristics of some 4(5)-amino-2-aryl-and 4(5)-amino-2-aryl-2-carboxy-methyl-l,3-indandiones have been studied in solvents of different polarity at room temperature and at 77 °K. In contrast to the 2-arylindan-l,3-diones unsubstituted in the phthaloyl fragment, the compounds investigated are photostable and fluoresce in the region 25 000-18 000 cm -1 with fluorescence quantum yields between 0.1 and 0.5. 
  Reference    Z. Naturforsch. 42a, 289—292 (1987); received October 22 1986 
  Published    1987 
  Keywords    4-and 5-amino indan-l, 3-diones, absorption, fluorescence, phosphorescence 
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 TEI-XML for    default:Reihe_A/42/ZNA-1987-42a-0289.pdf 
 Identifier    ZNA-1987-42a-0289 
 Volume    42 
28Author    J. Krzystek, H.J U C Von Schütz, Wolf, R.-D Stigler, J. J. StezowskiRequires cookie*
 Title    Characterization of the Phenanthrene-Tetrachlorophthalic Anhydride (P/TCPA) 1:1 Charge-Transfer Crystal: Spectroscopic and Structural Investigations  
 Abstract    The 1:1 phenanthrene-tetrachlorophthalic anhydride (P/TCPA) charge-transfer complex crystalizes with monoclinic symmetry, space group P2,, with two magnetically inequivalent stacks in the unit cell. The noncentrosymmetric space group is very unusual for CT-complexes. The optical emission spectra at low temperature are characterized by a strong CT phospho-rescence and a weak CT fluorescence and delayed fluorescence. The S, band lies at 22 800 ± 100 cm" 1 , the T, band at 21 200 ± 100 cm" 1 . Above 15 K triplet excitons, moving along the stacks are revealed by ESR. They have a CT character of about 30%, coinciding with that of the shallow X-traps found by ODMR at jow temperatures. A further trap, with zero-field-splitting (zfs) parameters of £> = ±0.0617, E = + 0.0116 cm" 1 has a much larger CT character of 50% as found in the isolated complex in low-temperature glass [1]. A structural model is proposed. 
  Reference    Z. Naturforsch. 42a, 622—630 (1987); received February 28 1987 
  Published    1987 
  Keywords    Charge-transfer crystal, crystal structure, fluorescence, phosphorescence, triplet excitons 
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 TEI-XML for    default:Reihe_A/42/ZNA-1987-42a-0622.pdf 
 Identifier    ZNA-1987-42a-0622 
 Volume    42 
29Author    Walter FabianRequires cookie*
 Title    W. Fabian * Eigenschaften von Molekülen in angeregten Zuständen 348 Properties of Molecules in Excited States  
 Abstract    Using bisisochinolin derivatives and related compounds it is shown that information about the fluorescent state can be obtained by comparison of experimental fluorescence data and calculated energies of the Si-state assuming various geometries. 
  Reference    Z. Naturforsch. 33b, 332—335 (1978); eingegangen am 7. September 1977 
  Published    1978 
  Keywords    Excited States, Fluorescence, PPP-Calculations, Phototautomerism, Bisisochinolin Deri-vatives 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0332.pdf 
 Identifier    ZNB-1978-33b-0332 
 Volume    33 
30Author    StuartM. Ridley, Peter HortonRequires cookie*
 Title    DCMU-Induced Fluorescence Changes and Photodestruction of Pigments Associated with an Inhibition of Photosystem I Cyclic Electron Flow  
 Abstract    Diuron (DCM U) induces the photodestruction o f pigm ents, w hich is the initial herbicidal symptom. As a working hypothesis, it is proposed that this sym ptom can only be produced when the herbicide dose is sufficiently high to inhibit not only photosystem II electron transport alm ost completely, but also inhibit (through over oxidation) the natural cyclic electron flow associated with photosystem I as well. Using freshly prepared chloroplasts, studies o f D C M U -induced fluorescence changes, and dose responses for inhibition o f electron transport, have been com ­ pared with a dose response for the photodestruction o f pigm ents in chloroplasts during 24 h illumination. Photodestruction o f pigm ents coincides with the inhibition o f cyclic flow. 
  Reference    Z. Naturforsch. 39c, 351 (1984); received October 10 1983 
  Published    1984 
  Keywords    Diuron (DCM U), Photodestruction, Fluorescence, Photosystem I, Cyclic Electron Flow 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0351.pdf 
 Identifier    ZNC-1984-39c-0351 
 Volume    39 
31Author    G. Renger, R. H. Agem Ann, W.F J V Erm AasRequires cookie*
 Title    Studies on the Functional Mechanism of System II Herbicides in Isolated Chloroplasts  
 Abstract    The effect o f specific proteolytic enzymes on variable fluorescence, p-benzoquinone-m ediated oxygen evolution, PS II herbicide (atrazine and brom oxynil) binding, and protein degradation has been analyzed in isolated class II pea chloroplasts. It was found that: 1. Trypsin and a lysine-specific protease effectively reduce the m axim um chlorophyll-a flu o­ rescence yield, whereas the initial fluorescence remains alm ost constant. At the sam e number o f enzymatic activity units both proteases have practically the sam e effect. 2 Trypsin and a lysine-specific protease inhibit the /»-benzoquinone-m ediated flash-induced oxygen evolution with trypsin being markedly more effective at the sam e num ber o f activity units o f both enzymes. Unstacked thylakoids exhibit a higher sensitivity to proteolytic degrada­ tion by both enzymes. 3. Trypsin and a lysine-specific protease reduce the binding capacity o f [14C]atrazine, but enhance that o f [l4C]bromoxynil (at long incubation tim es trypsin treatm ent also impairs bromoxynil binding). At the same specific activity a m arkedly longer treatm ent is required for the lysine-specific protease in order to achieve the same degree o f m odification as w ith trypsin. 4. Trypsin was found to attack the rapidly-turned-over 32 kD a-protein severely, whereas the lysine-specific protease does not m odify this polypeptide. On the other hand, the lysine-specific protease attacks the light harvesting com plex II. 5. Under our experimental conditions an arginine-specific protease did not affect chlorophyll-a fluorescence yield, /?-benzoquinone-mediated oxygen evolution, herbicide binding and the p oly­ peptide pattern. Based on these results a m echanism is proposed in w hich an as yet unidentified polypeptide with exposable lysine residues, as well as the lysine-free "Q B-protein" regulate the electron transfer from Q ^ to Q B and are involved in herbicide binding. 
  Reference    Z. Naturforsch. 39c, 362—367 (1984); received Decem ber 1 1983 
  Published    1984 
  Keywords    Chloroplasts, Proteolytic Enzymes, Fluorescence, Oxygen Evolution, H erbicide Binding 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0362.pdf 
 Identifier    ZNC-1984-39c-0362 
 Volume    39 
32Author    Shan-Yuan Yang, S. S. BrodyRequires cookie*
 Title    Effect of ß-Carotene on Delayed Light Emission from Aggregated Chlorophyll  
 Abstract    Delayed light emission (DLE) from aggregated chlorophyll is used to probe energy transfer between aggre­ gated chlorophyll and ß-carotene. Preilluminated ß-carotene when injected into a dark chamber containing aggregated chlorophyll, induces DLE from aggregated chlorophyll. If the dark chamber contains only monomeric chlorophyll, there is no DLE. The intensity of DLE is de­ pendent on the time of illumination of ß-carotene. The decay of energy stored by the carotene is not a first order process. The first half life is about 2 min, the next about 1 0 min. 
  Reference    Z. Naturforsch. 45c, 132—134 (1990); received February 6 /August 15 1989 
  Published    1990 
  Keywords    ß-Carotene, Delayed Light Emission, Chlorophyll Aggre­ gates, Fluorescence, Phosphorescence 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0132_n.pdf 
 Identifier    ZNC-1990-45c-0132_n 
 Volume    45 
33Author    Michael Bender, Ulrich Heber, K. Arl-, Josef DietzRequires cookie*
 Title    Saline Growth Conditions Favour Supercooling and Increase the Freezing Tolerance of Leaves of Barley and Wheat  
 Abstract    When young plants o f barley and wheat grown in hydroponic culture were subjected to salt stress, their freezing tolerance increased with increasing severity o f salt stress. Detached leaves from salt-stressed plants also exhibited an increased ability to supercool. A voidance o f ice for­ mation permitted leaf survival at subzero temperatures which were no longer tolerated when ice nucleation resulted in extracellular freezing. The increased freezing tolerance under salt stress is attributed to osm otic adjustment o f the plants. Increased cellular solute concentra­ tions decrease the extent o f cellular dehydration at freezing temperatures, thereby decreasing mechanical and chemical stresses on biomembranes during freezing and thawing. 
  Reference    Z. Naturforsch. 47c, 695—7 (1992); received M ay 14/July 9 1992 
  Published    1992 
  Keywords    Barley, Chlorophyll a, Fluorescence, Freezing Tolerance (Leaves), Salt Stress, Supercooling 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0695.pdf 
 Identifier    ZNC-1992-47c-0695 
 Volume    47 
34Author    G. Renger, H. M. Gleiter, E. Haag, F. ReifarthRequires cookie*
 Title    Photosystem II: Thermodynamics and Kinetics of Electron Transport from Qa" to Q b(Q b' ) and Deleterious Effects of Copper(II)  
 Abstract    Studies on thermodynamics and kinetics o f electron transfer from QA~ to QB(QB") were per­ formed by m onitoring laser flash induced changes o f the relative fluorescence emission as a function o f temperature (220 K < T < 310 K) in isolated thylakoids and PS II membrane frag­ ments. In addition, effects o f bivalent metal ions on PS II were investigated by measuring conven­ tional fluorescence induction curves, oxygen evolution, manganese content and atrazine bind­ ing mostly in PS II membrane fragments. It was found: a) the normalized level o f the fluores­ cence remaining 10 s after the actinic flash (FJF0) steeply increases at temperatures below -1 0 to -2 0 °C, b) the fast phase o f the transient fluorescence change becomes markedly retard­ ed with decreasing temperatures, c) am ong different cations (Cu2+, Zn2+, Cd2+, N i2+, Co2+) only Cu2+ exhibits marked effects in the concentration range below 100 jim and d) Cu2+ decreases the normalized variable fluorescence, inhibits oxygen evolution and diminishes the affinity to atrazine binding without affecting the number o f binding sites. The content o f about four manganeses per functionally competent oxygen evolving complex is not changed by [Cu2+] < 70 |iM. Based on these findings it is concluded: i) a temperature dependent equilibrium between an inactive (I) and active (A) state o f QA~ reoxidation by Q b(Qb) is characterized by standard 
  Reference    Z. Naturforsch. 48c, 234 (1993); received November 23 1992 
  Published    1993 
  Keywords    Photosystem II, Q B-Site, Copper(II) Effects, Fluorescence, Oxygen Evolution 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0234.pdf 
 Identifier    ZNC-1993-48c-0234 
 Volume    48 
35Author    ShigetohM. Iyachi11, JoachimB. Ürger, K. Iriakos, K. Otzabasisb, JensT. Hielm Annc, H. O. Rst SengerRequires cookie*
 Title    Photosynthetic Characteristics of Three Strains of Cyanobacteria Grown under Low-or High-C02 Conditions  
 Abstract    Quantum requirements of photosynthetic oxygen evolution at 679 nm, fluorescence em is­ sion spectra at liquid nitrogen temperature (77 K) and fluorescence induction kinetics in the presence of DCM U, were measured in the cyanobacteria Anabaena variabilis M3, Anabaena variabilis ATCC 29413 and A nacystis nidulans R2, each grown under low-or high-C02 condi­ tions. L o w -C 0 2 grown cells o f the cyanobacteria showed a higher quantum requirement of photosynthetic oxygen evolution and a higher ratio o f F7U)_740 to F680_700 fluorescence and a lower variable fluorescence in the presence of D CM U than high-C02 grown cells. These findings indicate a change in excitation energy distribution in favour of photosystem I. The result might be an enhancement in ATP formation caused by cyclic electron flow which in turn provokes dissolved inorganic carbon (D IC) accumulation in these low-C02 grown cells. 
  Reference    Z. Naturforsch. 51c, 40—4 (1996); received August 4/October 6 1995 
  Published    1996 
  Keywords    Quantum Requirement, Fluorescence, Dissolved Inorganic Carbon, Anabaena variabilis, Anacystis nidulans 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0040.pdf 
 Identifier    ZNC-1996-51c-0040 
 Volume    51 
36Author    SujataR M Ishra, SurendraChandra SabatRequires cookie*
 Title    Effect of Magnesium and Calcium Ions on the Photoelectron Transport Activity of Low-Salt Suspended Hydrilla verticillata Thylakoids: Possible Sites of Cation Interaction  
 Abstract    Stimulatory effect o f divalent cations like calcium (Ca2+) and magnesium (M g2+) was inves­ tigated on electron transport activity of divalent cation deficient low-salt suspended (LS) thylakoid preparation from a submerged aquatic angiosperm, Hydrilla verticillata. Both the cations stimulated electron transport activity of LS-suspended thylakoids having an intact water oxidation complex. But in hydroxylamine (N H 2OH) -or alkaline Tris -washed thyla­ koid preparations (with the water oxidation enzyme impaired), only Ca2+ dependent stimula­ tion of electron transport activity was found. The apparent K m of Ca2+ dependent stimulation of electron flow from H 20 (endogenous) or from artificial electron donor (exogenous) to dichlorophenol indophenol (acceptor) was found to be identical. Calcium supported stimula­ tion of electron transport activity in N H 2OH -or Tris -washed thylakoids was electron donor selective, i.e., Ca2+ ion was only effective in electron flow with diphenylcarbazide but not with N H 2OH as electron donor to photosystem II. A magnesium effect was observed in thylakoids having an intact water oxidation complex and the ion became unacceptable in N H 2OH -or Tris -washed thylakoids. Indirect experimental evidences have been presented to suggest that Mg2+ interacts with the water oxidation complex, while the Ca2+ interaction is localized betw een Y z and reaction center of photosystem II. 
  Reference    Z. Naturforsch. 53c, 849—8 (1998); received March 16/May 12 1998 
  Published    1998 
  Keywords    Aquatic Angiosperm, Divalent Cation, Electron Transport, Fluorescence, Hydrilla verticillata 
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 TEI-XML for    default:Reihe_C/53/ZNC-1998-53c-0849.pdf 
 Identifier    ZNC-1998-53c-0849 
 Volume    53 
37Author    U. Eberl, A. Ogrodnik, M. E. Michel-BeyerleRequires cookie*
 Title    Access to Primary Charge Separation Mechanism in Photosynthetic Reaction Centers: Anisotropic Excitation Spectra of Electric Field Modulated Fluorescence Yields  
 Abstract    Two-step sequential and unistep, superexchange primary electron transfer form primary radical pair states which differ in the direction and magnitude of their dipole moments as revealed in the X-ray structure analysis. The direction can be measured by the excitation anisotropy of electric field induced changes of the fluorescence yield. This method determines angles between the dipole of the primary radical pair and photoselected transition moments (in absorption and emission) of cofactors in the reaction centers. Transitions particularly favourable for discrimination between the two models of primary electron transfer are discussed. 
  Reference    Z. Naturforsch. 45a, 763—770 (1990); received March 17 1990 
  Published    1990 
  Keywords    Electric field effect, Anisotropy, Fluorescence, Photosynthesis, Reaction center, Pri-mary charge separation 
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 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-0763.pdf 
 Identifier    ZNA-1990-45a-0763 
 Volume    45 
38Author    I. Grabchev, I. Moneva, E. Wolarz3, D. Bauman3, S. StoyanovbRequires cookie*
 Title    Spectral Properties of 3-Benzanthrone Derivative Dyes in Isotropic Solvents, Polymer Film and Liquid Crystal  
 Abstract    Some recently synthesized benzanthrone derivatives bearing azomethine and oxy groups at C-3 po­ sition have been systematically studied. The influence of the substituents and of the environment (iso­ tropic and anisotropic media) on the absorption and fluorescence of the dyes and their vibronic transi­ tions is discussed in this paper. 
  Reference    Z. Naturforsch. 56a, 291—296 (2001); received January 24 2001 
  Published    2001 
  Keywords    3-Benzanthrone Derivatives, Azomethine and Oxy substitutes, Absorption, Fluorescence, Vibronic Structure 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0291.pdf 
 Identifier    ZNA-2001-56a-0291 
 Volume    56 
39Author    Wanda Wagner, Maria Zaborowska, Wlodzimierz Puzyna, David ShugarRequires cookie*
 Title    Studies on Purine-Pyrimidine Hydrogen Bonded Base Pairing by Means of Absorption and Emission Spectroscopy  
 Abstract    Procedures are described for measurement of association constants between potentially com­ plementary purine and pyrimidine bases by hydrogen bonding in non-aqueous medium by means of absorption and emission spectroscopy. The methods require that one of the two constituents be fluorescent and exhibit a long wavelength absorption band not, or only partially, overlapped by the second constituent. The foregoing has been applied to measurements of the association constants, and other parameters, of hydrogen-bonded complexes of 2-aminopurine with 1-substituted uracil, thymine and barbital in chloroform solution, both in the ground and excited states. It was estab­ lished that the 1:1 hydrogen-bonded base pairs 2-aminopurine : 1-cyclohexyluracil and 2-amino­ purine: 1-octylthymine maintain the ground-state equilibrium during the life time of the excited state, whereas for the corresponding pair 2-aminopurine: 1-methylbarbital this equilibrium is per­ turbed on excitation. The influence of N-alkylation of the 2-aminopurine residue on base-pairing with the pyrimidines has also been examined. The results are compared with those obtained by other methods. The specific advantages of the procedures employed, and their possible applications to studies on the behaviour of fluorescent residues in polynucleotides, are discussed. 
  Reference    (Z. Naturforsch. 29c, 672 [1974]; received August 1 1974) 
  Published    1974 
  Keywords    Purines and Pyrimidines, Hydrogen Bonding, Base-pairing, Excited States, Fluorescence 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0672.pdf 
 Identifier    ZNC-1974-29c-0672 
 Volume    29 
40Author    Helmut Wombacher, Monika Reuter-SmerdkaRequires cookie*
 Title    Spectrometric and Biological Data of l,N 6-Ethenoadenosine 3',5'-Cyclic Monophosphate  
  Reference    (Z. Naturforsch. 31c, 18 [1976]; received July 12/September 25 1975) 
  Published    1976 
  Keywords    ) l, N 6-Ethenoadenosine 3', 5'-Cyclic Monophosphate, Fluorescence, Spectra, Protein Kinase 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0018.pdf 
 Identifier    ZNC-1976-31c-0018 
 Volume    31 
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