| | 1 | Author
| Jack Farineau | Requires cookie* | | | Title
| In Pea Thylakoids, a Special Thermoluminescence Band Was Observed at Low Temperature after Photoinhibitory Treatments Performed under Aerobic Conditions, either in vivo (in Leaf) or in vitro  | | | | Abstract
| Characteristics o f thermoluminescence (TL) glow curves were studied in thylakoids isolated from pea leaves after an exposure to very high light in the TL device. The inhibition o f p h oto synthesis was detected both as decreases o f oxygen evolution rates and o f variable fluores cence. In another more classical experiment, leaves were exposed to high light at low tempera ture (5 °C) for 4 h and recovery o f normal PS II characteristics were followed during a 20 h time period under low light at 20 °C. TL study was performed on thylakoids isolated from these leaves. Charging o f bands was performed by an illumination at low temperature (-8 0 °C). Illumination at low temperature (-8 0 °C) induces 2 types o f TL bands called Z variable (Zv) band peaking at about —70 °C and a classical B band peaking at 35 °C. B band is ascribed to recombination in pairs S2/3QB", whereas the origin o f Zv bands remains unclear. M odified Zv bands, with flat shape and presenting a large part resistant to ethanol, were evidenced after som e minutes o f dark adaptation, both in light-exposed thylakoids and in thylakoids isolated from photoinhibited leaves. This ethanol resistant part in Zv band was only induced by p h oto inhibitory treatment performed under aerobic conditions (2 1 % 0 2 in media), both in vitro and in vivo; thus, the appearance o f the special Zv band would be related to an oxidative process accompanying photoinhibition. B bands presented reduced sizes and a shift o f peak maximum o f about 5 °C after some minutes o f dark adaptation. In vivo, the recovery o f a high PS II activ ity and o f B bands displaying normal characteristics occurs parallely to reappearance o f Zv bands with normal shape and with a vestigial ethanol resistant band. | | | |
Reference
| Z. Naturforsch. 47c, 875—8 (1992); received July 27/A ugust 27 1992 | | | |
Published
| 1992 | | | |
Keywords
| Pea, Photoinhibition, Photosystem II, Thermoluminescence, Thylakoid, Zv Band | | | |
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| default:Reihe_C/47/ZNC-1992-47c-0875.pdf | | | | Identifier
| ZNC-1992-47c-0875 | | | | Volume
| 47 | |
| 3 | Author
| ChunheX. Ua, Yong Zhub, Govindjeeac | Requires cookie* | | | Title
| Differential Inhibition and Rephasing of Photosystem II Electron Acceptor Side by Monohalogenated Acetates of Different Hydrophobicity | | | | Abstract
| We demonstrate here that monohalogenated acetates (M F A , m onofluoroacetate; M CA, m onochloroacetate; M BA, monobrom oacetate) are unique probes o f the electron acceptor side o f the photosystem II (PS II) reaction center: (1) they differentially inhibit the reoxidation o f the reduced primary plastoquinone electron acceptor, QA~, by the secondary plastoquinone electron acceptor QB, and increase the equilibrium [QA_] in the order: M BA > M C A > M FA; and (2) M CA and M BA rephase the PS II electron acceptor side, a rather unusual effect. This results in flash number dependence o f [QA_] with maxima at even flashes to change to odd flashes. Furthermore, we demonstrate a correlation between the inhibitory activity o f the halo-genated acetates with their hydrophobicity (i.e., partition coefficient). | | | |
Reference
| Z. Naturforsch. 47c, 711—7 (1992); received June 2 1992 | | | |
Published
| 1992 | | | |
Keywords
| M onohalogenated Acetates, Photosystem II, Two Electron Gate, Hydrophobicity, Bicarbonate Effect | | | |
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| default:Reihe_C/47/ZNC-1992-47c-0711.pdf | | | | Identifier
| ZNC-1992-47c-0711 | | | | Volume
| 47 | |
| 5 | Author
| Klaus-Peter Michel, ElfriedeK. Pistorius, E. Gau, G. Wälzlein, S. Gärtner, M. Kuhlmann, E. K. Pistorius | Requires cookie* | | | Title
| Isolation of a Photosystem II Associated 36 kDa Polypeptide and an Iron-Stress 34 kDa Polypeptide from Thylakoid Membranes of the Cyanobacterium Synechococcus PCC 6301 Grown under Mild Iron Deficiency | | | | Abstract
| A 36 kDa polypeptide which previously was shown to be present in purified photosystem II complexes from Synechococcus PCC 6301 and which crossreacts with the antiserum raised against the soluble L-amino acid oxidase o f 50 kD a from Synechococcus PCC 6301 (A. was isolated from thylakoid membranes o f the same cyanobacterium grown under mild iron deficiency. This peptide is present in about equal am ounts in thylakoid membranes o f Syne chococcus PCC 6301 grown under regular or iron deficient conditions. The antiserum raised against this thylakoid membrane bound 36 kD a peptide crossreacts with the soluble L-amino acid oxidase o f 50 kDa. These results further support our conclusion that the thylakoid mem brane bound 36 kD a polypeptide is a modified form o f the soluble 50 kD a L-amino acid oxi dase. In addition, a 34 kD a polypeptide was isolated from iron stressed thylakoid membranes, and an antiserum was also raised against this protein. Im m unoblot experiments with this an tiserum show that the 34 kD a peptide is present in elevated amounts in thylakoid membranes from Synechococcus cells grown under iron deficiency and that it is alm ost absent in thylakoid membranes from cells grown under regular conditions. | | | |
Reference
| Z. Naturforsch. 47c, 867—8 (1992); received August 4/O ctober 8 1992 | | | |
Published
| 1992 | | | |
Keywords
| Cyanobacteria, Synechococcus PCC 6301, Photosystem II, L-Amino Acid Oxidase, Iron Stress | | | |
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| default:Reihe_C/47/ZNC-1992-47c-0867.pdf | | | | Identifier
| ZNC-1992-47c-0867 | | | | Volume
| 47 | |
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