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'Fluorescence Lifetimes' in keywords Facet   section ZfN Section C  [X]
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1996 (1)
1982 (2)
1981 (1)
1Author    S. S. Brody, J. Barber, C. Tredwell, G. BeddardRequires cookie*
 Title    Effects of Linolenic Acid on the Spectral Properties and Picosecond Fluorescence of Pea Chloroplasts  
 Abstract    Linolenic acid induces changes in the absorption spectrum and in the picosecond fluorescence of pea chloroplasts. The effects o f linolenic acid are dependent on concentration and time. Linolenic acid increases the fluorescence life time o f chloroplasts at room temperature. The contribution of the slow fluorescence component relative to the fast component is increased almost 10 fold in the presence o f 0.5 m M linolenic acid. The synergistic action o f digitonin and linolenic acid increases the ratio o f "closed" to "open" traps in the photosynthetic units. Upon addition o f 0.5 m M linolenic acid there are increases in absorbance at 676 and 436 nm, and decreases in absorbance at 705 and 496 nm. Some o f the spectral changes have a biphasic character, they reach a maxi um um after about 30 min then start to reverse. Based on the spectral changes at 496 and 705 nm it appears that linolenic acid has at least two effects, e. it modifies the thylakoid membrane and secondarily decreases the concentration of P 700, respectively. 
  Reference    Z. Naturforsch. 36c, 1021—1024 (1981); received May 201981 
  Published    1981 
  Keywords    Photosynthesis, Chloroplasts, Fluorescence Lifetimes, Linolenic Acid, Spectral Changes 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-1021.pdf 
 Identifier    ZNC-1981-36c-1021 
 Volume    36 
2Author    SeymourSteven BrodyRequires cookie*
 Title    Absorption and Picosecond Fluorescence Characteristics o f Chlorophyll Vesicles as a Function o f Temperature  
 Abstract    With chlorophyll a-dipalmitoylphosphatidylcholine-liposomes, the absorption increases at 706 and 450 nm, and decreases at 660 and 420 nm, as the temperature is lowered. As the temperature is increased opposite changes are observed. A lipid phase change occurs at 34°. The pigment to lipid ratio is 1 to 5 in the liposome. With chlorophyll a-soy bean lecithin-liposomes the absorption increases at 706, 680 and 440 nm, and decreases at 650 and 430 nm, as the temperature is lowered. As the temperature is increased, opposite changes are observed. A lipid phase change occurs at 26-27 °C. The pigment to lipid ratio is 1 to 13. The spectral change at 706 nm is identified with aggregated chlorophyll. The concentration o f chlorophyll aggregate increases as the temperature is lowered, and decreases as the temperature is raised. Fluorescence decay from chlorophyll a-soy bean lecithin-liposomes is biphasic. The lifetimes o f freshly prepared liposomes are 121 ± 4 ps and 1400 + 200 ps. The relative contribution o f the fast and slow fluorescence components are modified by temperature. Heating results in an increase in both lifetimes, and an increase in fluorescence from the long lived component. These changes are interpreted as resulting from a decrease in energy transfer and concentration quenching. The origin o f the biphasic fluorescence and spectral transformations in liposomes, and the possible re­ lation between in vitro and in vivo picosecond fluorescence is discussed. 
  Reference    Z. Naturforsch. 37c, 260—267 (1982); received October 161981 
  Published    1982 
  Keywords    Liposome, Chlorophyll, Photosynthesis, Fluorescence Lifetime, Lipid Phase Change 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0260.pdf 
 Identifier    ZNC-1982-37c-0260 
 Volume    37 
3Author    S. S. BrodyRequires cookie*
 Title    Effect of Aging on the Fluorescence Lifetime of Chloroplasts  
 Abstract    The lifetime of fluorescence from pea chloroplasts at room temperature increases with age. The ratio of the fluorescence intensities of the slow to fast decay components, decreases with age o f the chloroplasts. This observation can account for the wide range o f lifetimes reported in the literature. The variability of biological material (cultured and prepared with similar procedures) introduces considerable variation in the fluorescence lifetimes measured with pea chloroplasts. Sonication of chloroplasts results in an increase in both the fast and slow fluorescence lifetimes. 
  Reference    Z. Naturforsch. 37c, 881—883 (1982); received January 4/May 24 1982 
  Published    1982 
  Keywords    Photosynthesis, Fluorescence Lifetimes, Aging, Sonicated Chloroplasts 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0881.pdf 
 Identifier    ZNC-1982-37c-0881 
 Volume    37 
4Author    G. H. Schmida, A. R. Adunz3, K.P B Ader3, B. Myśliwa-Kurdzielb, K. Strzał, J. KrukbRequires cookie*
 Title    Action of an Antiserum to a-Tocoquinone on Photosystem II-Particle Preparations of N icotiana tabacum  
 Abstract    An antiserum to a-tocoquinone was prepared by immunization of rabbits. Immunization was obtained by injection of a conjugate consisting of the hapten a-tocoquinone attached to methylated ovalbumin into the rabbit. The antiserum recognizes the 3,4-dimethyl-p-benzo-quinone group of the m olecule as well as part of the immediate vicinity to the side chain. This is concluded from the fact that the antibody has som e affinity also to plastoquinone. No reaction of the antibody is observed with a-tocopherol hydroquinone or a-tocopherol. Reac­ tion of the antiserum to a-tocoquinone with photosystem Il-particle preparations from to­ bacco affects the functionality of the preparation. Chlorophylla-fluorescence emission is quenched without an alteration of the em ission spectrum. Concomitant with this fluorescence quenching, the lifetime of two fluorescence com ponents namely that of a fast and a slower component are shortened. By analogy with the literature the fast component is associated with chlorophylla of the reaction center core and that of the slow com ponent with the antenna system in which the lifetime parameter is shortened by the antibody from 3.42 ns to 1.795 ns. The action on the fast component is less and leads to a shortening of the lifetime parame­ ter from 0.373 ns to only 0.249 ns. The effect is interpreted in terms of an enhancement of linear photosynthetic electron transport possibly due to an inhibition of the cyclic electron transport around PS II, discovered by Gruszecki et al. 
  Reference    Z. Naturforsch. 51c, 691—6 (1996); received May 14/July 17 1996 
  Published    1996 
  Keywords    Antiserum, a-Tocoquinone, Photosystem II, Fluorescence Lifetime, Nicotiana tabacum 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0691.pdf 
 Identifier    ZNC-1996-51c-0691 
 Volume    51